miR-155 modulates the progression of neuropathic pain through targeting SGK3

PubMed Central

Liu, Shaoxing; Zhu, Bo; Sun, Yan; Xie, Xianfeng

2015-01-01

This study aimed to illustrate the potential effects of miR-155 in neuropathic pain and its potential mechanism. Spragure-Dawley (SD) rats were used for neuropathic pain model of bilateral chronic constriction injury (bCCI) construction. Effects of miR-155 expression on pain threshold of mechanical stimuli (MWT), paw withdrawal threshold latency (PMTL) and cold threshold were analyzed. Target for miR-155 was analyzed using bioinformatics methods. Moreover, effects of miR-155 target gene expression on pain thresholds were also assessed. Compared with the controls and sham group, miR-155 was overexpressed in neuropathic pain rats (P<0.05), but miR-155 slicing could significantly decreased the pain thresholds (P<0.05). Serum and glucocorticoid regulated protein kinase 3 (SGK3) was predicted as the target gene for miR-155, and miR-155 expression was negatively correlated to SGK3 expression. Furthermore, SGK3 overexpression could significantly decreased the pain thresholds which was the same as miR-155 (P<0.05). Moreover, miR-155 slicing and SGK3 overexpression could significantly decrease the painthreshold. The data presented in this study suggested that miR-155 slicing could excellently alleviate neuropathic pain in rats through targeting SGK3 expression. miR-155 may be a potential therapeutic target for neuropathic pain treatment. PMID:26823753

MiR-155 modulates the progression of neuropathic pain through targeting SGK3.

PubMed

Liu, Shaoxing; Zhu, Bo; Sun, Yan; Xie, Xianfeng

2015-01-01

This study aimed to illustrate the potential effects of miR-155 in neuropathic pain and its potential mechanism. Spragure-Dawley (SD) rats were used for neuropathic pain model of bilateral chronic constriction injury (bCCI) construction. Effects of miR-155 expression on pain threshold of mechanical stimuli (MWT), paw withdrawal threshold latency (PMTL) and cold threshold were analyzed. Target for miR-155 was analyzed using bioinformatics methods. Moreover, effects of miR-155 target gene expression on pain thresholds were also assessed. Compared with the controls and sham group, miR-155 was overexpressed in neuropathic pain rats (P<0.05), but miR-155 slicing could significantly decreased the pain thresholds (P<0.05). Serum and glucocorticoid regulated protein kinase 3 (SGK3) was predicted as the target gene for miR-155, and miR-155 expression was negatively correlated to SGK3 expression. Furthermore, SGK3 overexpression could significantly decreased the pain thresholds which was the same as miR-155 (P<0.05). Moreover, miR-155 slicing and SGK3 overexpression could significantly decrease the painthreshold. The data presented in this study suggested that miR-155 slicing could excellently alleviate neuropathic pain in rats through targeting SGK3 expression. miR-155 may be a potential therapeutic target for neuropathic pain treatment.

Active and passive distraction using a head-mounted display helmet: effects on cold pressor pain in children.

PubMed

Dahlquist, Lynnda M; McKenna, Kristine D; Jones, Katia K; Dillinger, Lindsay; Weiss, Karen E; Ackerman, Claire Sonntag

2007-11-01

The current study tested the effectiveness of interactive versus passive distraction that was delivered via a virtual reality type head-mounted display helmet for children experiencing cold pressor pain. Forty children, aged 5 to 13 years, underwent 1 or 2 baseline cold pressor trials followed by interactive distraction and passive distraction trials in counterbalanced order. Pain threshold and pain tolerance. Children who experienced either passive or interactive distraction demonstrated significant improvements in both pain tolerance and pain threshold relative to their baseline scores. In contrast, children who underwent a second cold pressor trial without distraction showed no significant improvements in pain tolerance or threshold. Although both distraction conditions were effective, the interactive distraction condition was significantly more effective. Implications for the treatment of children's distress during painful medical procedures are discussed. (PsycINFO Database Record (c) 2007 APA, all rights reserved).

Experimental Psychological Stress on Quantitative Sensory Testing Response in Patients with Temporomandibular Disorders.

PubMed

Araújo Oliveira Ferreira, Dyna Mara; Costa, Yuri Martins; de Quevedo, Henrique Müller; Bonjardim, Leonardo Rigoldi; Rodrigues Conti, Paulo César

2018-05-15

To assess the modulatory effects of experimental psychological stress on the somatosensory evaluation of myofascial temporomandibular disorder (TMD) patients. A total of 20 women with myofascial TMD and 20 age-matched healthy women were assessed by means of a standardized battery of quantitative sensory testing. Cold detection threshold (CDT), warm detection threshold (WDT), cold pain threshold (CPT), heat pain threshold (HPT), mechanical pain threshold (MPT), wind-up ratio (WUR), and pressure pain threshold (PPT) were performed on the facial skin overlying the masseter muscle. The variables were measured in three sessions: before (baseline) and immediately after the Paced Auditory Serial Addition Task (PASAT) (stress) and then after a washout period of 20 to 30 minutes (poststress). Mixed analysis of variance (ANOVA) was applied to the data, and the significance level was set at P = .050. A significant main effect of the experimental session on all thermal tests was found (ANOVA: F > 4.10, P < .017), where detection tests presented an increase in thresholds in the poststress session compared to baseline (CDT, P = .012; WDT, P = .040) and pain thresholds were reduced in the stress (CPT, P < .001; HPT, P = .001) and poststress sessions (CPT, P = .005; HPT, P = .006) compared to baseline. In addition, a significant main effect of the study group on all mechanical tests (MPT, WUR, and PPT) was found (ANOVA: F > 4.65, P < .037), where TMD patients were more sensitive than healthy volunteers. Acute mental stress conditioning can modulate thermal sensitivity of the skin overlying the masseter in myofascial TMD patients and healthy volunteers. Therefore, psychological stress should be considered in order to perform an unbiased somatosensory assessment of TMD patients.

Anaerobic Threshold and Salivary α-amylase during Incremental Exercise.

PubMed

Akizuki, Kazunori; Yazaki, Syouichirou; Echizenya, Yuki; Ohashi, Yukari

2014-07-01

[Purpose] The purpose of this study was to clarify the validity of salivary α-amylase as a method of quickly estimating anaerobic threshold and to establish the relationship between salivary α-amylase and double-product breakpoint in order to create a way to adjust exercise intensity to a safe and effective range. [Subjects and Methods] Eleven healthy young adults performed an incremental exercise test using a cycle ergometer. During the incremental exercise test, oxygen consumption, carbon dioxide production, and ventilatory equivalent were measured using a breath-by-breath gas analyzer. Systolic blood pressure and heart rate were measured to calculate the double product, from which double-product breakpoint was determined. Salivary α-amylase was measured to calculate the salivary threshold. [Results] One-way ANOVA revealed no significant differences among workloads at the anaerobic threshold, double-product breakpoint, and salivary threshold. Significant correlations were found between anaerobic threshold and salivary threshold and between anaerobic threshold and double-product breakpoint. [Conclusion] As a method for estimating anaerobic threshold, salivary threshold was as good as or better than determination of double-product breakpoint because the correlation between anaerobic threshold and salivary threshold was higher than the correlation between anaerobic threshold and double-product breakpoint. Therefore, salivary threshold is a useful index of anaerobic threshold during an incremental workload.

Effect of butorphanol on thermal nociceptive threshold in healthy pony foals.

PubMed

McGowan, K T; Elfenbein, J R; Robertson, S A; Sanchez, L C

2013-07-01

Pain management is an important component of foal nursing care, and no objective data currently exist regarding the analgesic efficacy of opioids in foals. To evaluate the somatic antinociceptive effects of 2 commonly used doses of intravenous (i.v.) butorphanol in healthy foals. Our hypothesis was that thermal nociceptive threshold would increase following i.v. butorphanol in a dose-dependent manner in both neonatal and older pony foals. Seven healthy neonatal pony foals (age 1-2 weeks), and 11 healthy older pony foals (age 4-8 weeks). Five foals were used during both age periods. Treatments, which included saline (0.5 ml), butorphanol (0.05 mg/kg bwt) and butorphanol (0.1 mg/kg bwt), were administered i.v. in a randomised crossover design with at least 2 days between treatments. Response variables included thermal nociceptive threshold, skin temperature and behaviour score. Data within each age period were analysed using a 2-way repeated measures ANOVA, followed by a Holm-Sidak multiple comparison procedure if warranted. There was a significant (P<0.05) increase in thermal threshold, relative to Time 0, following butorphanol (0.1 mg/kg bwt) administration in both age groups. No significant time or treatment effects were apparent for skin temperature. Significant time, but not treatment, effects were evident for behaviour score in both age groups. Butorphanol (0.1 mg/kg bwt, but not 0.05 mg/kg bwt) significantly increased thermal nociceptive threshold in neonatal and older foals without apparent adverse behavioural effects. Butorphanol shows analgesic potential in foals for management of somatic painful conditions. © 2012 EVJ Ltd.

Identifying community thresholds for lotic benthic diatoms in response to human disturbance.

PubMed

Tang, Tao; Tang, Ting; Tan, Lu; Gu, Yuan; Jiang, Wanxiang; Cai, Qinghua

2017-06-23

Although human disturbance indirectly influences lotic assemblages through modifying physical and chemical conditions, identifying thresholds of human disturbance would provide direct evidence for preventing anthropogenic degradation of biological conditions. In the present study, we used data obtained from tributaries of the Three Gorges Reservoir in China to detect effects of human disturbance on streams and to identify disturbance thresholds for benthic diatoms. Diatom species composition was significantly affected by three in-stream stressors including TP, TN and pH. Diatoms were also influenced by watershed % farmland and natural environmental variables. Considering three in-stream stressors, TP was positively influenced by % farmland and % impervious surface area (ISA). In contrast, TN and pH were principally affected by natural environmental variables. Among measured natural environmental variables, average annual air temperature, average annual precipitation, and topsoil % CaCO 3 , % gravel, and total exchangeable bases had significant effects on study streams. When effects of natural variables were accounted for, substantial compositional changes in diatoms occurred when farmland or ISA land use exceeded 25% or 0.3%, respectively. Our study demonstrated the rationale for identifying thresholds of human disturbance for lotic assemblages and addressed the importance of accounting for effects of natural factors for accurate disturbance thresholds.

Analgesic effect of butorphanol and levomethadone in detomidine sedated horses.

PubMed

Schatzman, U; Armbruster, S; Stucki, F; Busato, A; Kohler, I

2001-08-01

The analgesic potency of butorphanol 25 microg/kg bodyweight (BW) and levomethadone 100 microg/kg BW, administered together with detomidine 10 microg/kg BW, was measured in twelve Warmblood horses in a randomized, blinded cross-over study. Detomidine with saline 10 ml 0.9% was used as placebo. The nociceptive threshold was determined using a constant current and a pneumatic pressure model for somatic pair Detomidine alone and in combination with butorphanol or levomethadone caused a significant temporary increase (P < 0.05) of the nociceptive threshold with a maximum effect within 15 min and a return to baseline levels within 90 min. Butorphanol and levomethadone increased the nociceptive threshold and prolonged the duration of anti-nociception significantly from 15 to 75 min (P < 0.05) after drug administration compared with detomidine alone to both test methods. No significant difference between butorphanol and levomethadone was registered. It is concluded that the addition of butorphanol or levomethadone to detomidine increases the nociceptive threshold to somatic pain and prolongs the analgesic effect of detomidine in the horse.

Effect of postprandial thermogenesis on the cutaneous vasodilatory response during exercise.

PubMed

Hayashi, Keiji; Ito, Nozomi; Ichikawa, Yoko; Suzuki, Yuichi

2014-08-01

To examine the effect of postprandial thermogenesis on the cutaneous vasodilatory response, 10 healthy male subjects exercised for 30 min on a cycle ergometer at 50% of peak oxygen uptake, with and without food intake. Mean skin temperature, mean body temperature (Tb), heart rate, oxygen uptake, carbon dioxide elimination, and respiratory quotient were all significantly higher at baseline in the session with food intake than in the session without food intake. To evaluate the cutaneous vasodilatory response, relative laser Doppler flowmetry values were plotted against esophageal temperature (Tes) and Tb. Regression analysis revealed that the [Formula: see text] threshold for cutaneous vasodilation tended to be higher with food intake than without it, but there were no significant differences in the sensitivity. To clarify the effect of postprandial thermogenesis on the threshold for cutaneous vasodilation, the between-session difference in the Tes threshold and the Tb threshold were plotted against the between-session difference in baseline Tes and baseline Tb, respectively. Linear regression analysis of the resultant plot showed significant positive linear relationships (Tes: r = 0.85, P < 0.01; Tb: r = 0.67, P < 0.05). These results suggest that postprandial thermogenesis increases baseline body temperature, which raises the body temperature threshold for cutaneous vasodilation during exercise.

Lumbopelvic Core Stabilization Exercise and Pain Modulation Among Individuals with Chronic Nonspecific Low Back Pain.

PubMed

Paungmali, Aatit; Joseph, Leonard H; Sitilertpisan, Patraporn; Pirunsan, Ubon; Uthaikhup, Sureeporn

2017-11-01

Lumbopelvic stabilization training (LPST) may provide therapeutic benefits on pain modulation in chronic nonspecific low back pain conditions. This study aimed to examine the effects of LPST on pain threshold and pain intensity in comparison with the passive automated cycling intervention and control intervention among patients with chronic nonspecific low back pain. A within-subject, repeated-measures, crossover randomized controlled design was conducted among 25 participants (7 males and 18 females) with chronic nonspecific low back pain. All the participants received 3 different types of experimental interventions, which included LPST, the passive automated cycling intervention, and the control intervention randomly, with 48 hours between the sessions. The pressure pain threshold (PPT), hot-cold pain threshold, and pain intensity were estimated before and after the interventions. Repeated-measures analysis of variance showed that LPST provided therapeutic effects as it improved the PPT beyond the placebo and control interventions (P < 0.01). The pain intensity under the LPST condition was significantly better than that under the passive automated cycling intervention and controlled intervention (P < 0.001). Heat pain threshold under the LPST condition also showed a significant trend of improvement beyond the control (P < 0.05), but no significant effects on cold pain threshold were evident. Lumbopelvic stabilization training may provide therapeutic effects by inducing pain modulation through an improvement in the pain threshold and reduction in pain intensity. LPST may be considered as part of the management programs for treatment of chronic low back pain. © 2017 World Institute of Pain.

Increase of olfactory threshold in plating factory workers exposed to chromium in Korea.

PubMed

Kitamura, Fumihiko; Yokoyama, Kazuhito; Araki, Shunichi; Nishikitani, Mariko; Choi, Jae-Wook; Yum, Youg-Tae; Park, Hee-Chan; Park, Sang-Hwoi; Sato, Hajime

2003-07-01

To disclose the effects of chromium (Cr) on olfactory function, olfactory threshold tests were conducted on 27 male plating workers (Cr workers) with signs and symptoms of olfactory irritation but without nasal septum perforation or ulcer and on 34 male control subjects in Korean plating factories. The Cr workers had been exposed to Cr fume for 0.9 to 18.2 (mean 7.9) years; their blood Cr concentrations (0.16-3.69, mean 1.29 microg/dl) were significantly higher than those of the 34 control subjects (0.04-1.95, mean 0.55 microg/dl). Scores on recognition thresholds among the Cr workers were significantly higher than those of the control subjects (p < 0.05) and related positively and significantly to the exposure periods of the 27 Cr workers (p < 0.05). Olfactory thresholds were not significantly different between the Cr workers with and without nasal signs or symptoms, except that the scores on the recognition threshold were significantly higher in those experiencing difficulty with smell (p < 0.05). It is suggested that olfactory threshold is affected by Cr without development of nasal septum perforation or ulceration.

A factorization approach to next-to-leading-power threshold logarithms

NASA Astrophysics Data System (ADS)

Bonocore, D.; Laenen, E.; Magnea, L.; Melville, S.; Vernazza, L.; White, C. D.

2015-06-01

Threshold logarithms become dominant in partonic cross sections when the selected final state forces gluon radiation to be soft or collinear. Such radiation factorizes at the level of scattering amplitudes, and this leads to the resummation of threshold logarithms which appear at leading power in the threshold variable. In this paper, we consider the extension of this factorization to include effects suppressed by a single power of the threshold variable. Building upon the Low-Burnett-Kroll-Del Duca (LBKD) theorem, we propose a decomposition of radiative amplitudes into universal building blocks, which contain all effects ultimately responsible for next-to-leading-power (NLP) threshold logarithms in hadronic cross sections for electroweak annihilation processes. In particular, we provide a NLO evaluation of the radiative jet function, responsible for the interference of next-to-soft and collinear effects in these cross sections. As a test, using our expression for the amplitude, we reproduce all abelian-like NLP threshold logarithms in the NNLO Drell-Yan cross section, including the interplay of real and virtual emissions. Our results are a significant step towards developing a generally applicable resummation formalism for NLP threshold effects, and illustrate the breakdown of next-to-soft theorems for gauge theory amplitudes at loop level.

Effect of density of localized states on the ovonic threshold switching characteristics of the amorphous GeSe films

NASA Astrophysics Data System (ADS)

Ahn, Hyung-Woo; Seok Jeong, Doo; Cheong, Byung-ki; Lee, Hosuk; Lee, Hosun; Kim, Su-dong; Shin, Sang-Yeol; Kim, Donghwan; Lee, Suyoun

2013-07-01

We investigated the effect of nitrogen (N) doping on the threshold voltage of an ovonic threshold switching device using amorphous GeSe. Using the spectroscopic ellipsometry, we found that the addition of N brought about significant changes in electronic structure of GeSe, such as the density of localized states and the band gap energy. Besides, it was observed that the characteristics of OTS devices strongly depended on the doping of N, which could be attributed to those changes in electronic structure suggesting a method to modulate the threshold voltage of the device.

Scaling Laws for NanoFET Sensors

NASA Astrophysics Data System (ADS)

Wei, Qi-Huo; Zhou, Fu-Shan

2008-03-01

In this paper, we report our numerical studies of the scaling laws for nanoplate field-effect transistor (FET) sensors by simplifying the nanoplates as random resistor networks. Nanowire/tube FETs are included as the limiting cases where the device width goes small. Computer simulations show that the field effect strength exerted by the binding molecules has significant impact on the scaling behaviors. When the field effect strength is small, nanoFETs have little size and shape dependence. In contrast, when the field-effect strength becomes stronger, there exists a lower detection threshold for charge accumulation FETs and an upper detection threshold for charge depletion FET sensors. At these thresholds, the nanoFET devices undergo a transition between low and large sensitivities. These thresholds may set the detection limits of nanoFET sensors. We propose to eliminate these detection thresholds by employing devices with very short source-drain distance and large width.

Hydrogen peroxide preferentially activates capsaicin-sensitive high threshold afferents via TRPA1 channels in the guinea pig bladder.

PubMed

Nicholas, S; Yuan, S Y; Brookes, S J H; Spencer, N J; Zagorodnyuk, V P

2017-01-01

There is increasing evidence suggesting that ROS play a major pathological role in bladder dysfunction induced by bladder inflammation and/or obstruction. The aim of this study was to determine the effect of H 2 O 2 on different types of bladder afferents and its mechanism of action on sensory neurons in the guinea pig bladder. 'Close-to-target' single unit extracellular recordings were made from fine branches of pelvic nerves entering the guinea pig bladder, in flat sheet preparations, in vitro. H 2 O 2 (300-1000 μM) preferentially and potently activated capsaicin-sensitive high threshold afferents but not low threshold stretch-sensitive afferents, which were only activated by significantly higher concentrations of hydrogen peroxide. The TRPV1 channel agonist, capsaicin, excited 86% of high threshold afferents. The TRPA1 channel agonist, allyl isothiocyanate and the TRPM8 channel agonist, icilin activated 72% and 47% of capsaicin-sensitive high threshold afferents respectively. The TRPA1 channel antagonist, HC-030031, but not the TRPV1 channel antagonist, capsazepine or the TRPM8 channel antagonist, N-(2-aminoethyl)-N-[[3-methoxy-4-(phenylmethoxy)phenyl]methyl]thiophene-2-carboxamide, significantly inhibited the H 2 O 2 -induced activation of high threshold afferents. Dimethylthiourea and deferoxamine did not significantly change the effect of H 2 O 2 on high threshold afferents. The findings show that H 2 O 2 , in the concentration range detected in inflammation or reperfusion after ischaemia, evoked long-lasting activation of the majority of capsaicin-sensitive high threshold afferents, but not low threshold stretch-sensitive afferents. The data suggest that the TRPA1 channels located on these capsaicin-sensitive afferent fibres are probable targets of ROS released during oxidative stress. © 2016 The British Pharmacological Society.

Effects of alcohol and noise on temporary threshold shift in Guinea pigs.

PubMed

Liu, Tien-Chen; Hsu, Chuan-Jen; Hwang, Juen-Haur; Tseng, Fen-Yu; Chen, Yuh-Shyang

2004-01-01

The purpose of this study was to investigate the effects of concomitant exposure to noise and alcohol on the auditory thresholds. Twenty-four guinea pigs were equally divided into three groups: the acute intoxication group, the chronic intoxication group and the control group. Animals in the acute group received single intraperitoneal injections of ethanol (2 g/kg). In the chronic group, alcohol was administered via drinking water (10%, v/v) over a 60-day period. All animals were exposed to a white noise at the intensity of 105 dB A for 30 min. Auditory brainstem response (ABR) thresholds and distortion product otoacoustic emission (DPOAE) levels were measured before, immediately after noise exposure and also 1, 2, and 7 days following exposure. The results showed: first, acute alcohol injection caused a significant, temporary elevation of ABR threshold (4.8 dB in average), while chronic alcohol treatment did not change auditory threshold significantly. Second, noise exposure induced a mean threshold shift of 15.4- 19.7 dB. ABR threshold returned to normal 2 days after exposure. Both acute and chronic alcohol treatment did not alter the magnitude and time course of recovery of the temporary threshold shift (TTS). Third, the mean DPOAE amplitudes decreased at most frequencies following acute injection of alcohol. However, the differences did not reach statistical significance. Fourth, the mean DPOAE levels dropped 3.4-9.6 dB in all groups after noise exposure and returned to normal 1 day to 2 days after noise. There were no significant differences in the amount of DPOAE suppression after noise between the three groups. In summary, we have found that acute and chronic treatment of alcohol in combination with noise did not significantly exacerbate TTS or decrease DPOAE amplitudes relative to noise exposure alone. Copyright 2004 S. Karger AG, Basel

Effect of Age and Severity of Facial Palsy on Taste Thresholds in Bell's Palsy Patients

PubMed Central

Park, Jung Min; Kim, Myung Gu; Jung, Junyang; Kim, Sung Su; Jung, A Ra; Kim, Sang Hoon

2017-01-01

Background and Objectives To investigate whether taste thresholds, as determined by electrogustometry (EGM) and chemical taste tests, differ by age and the severity of facial palsy in patients with Bell's palsy. Subjects and Methods This study included 29 patients diagnosed with Bell's palsy between January 2014 and May 2015 in our hospital. Patients were assorted into age groups and by severity of facial palsy, as determined by House-Brackmann Scale, and their taste thresholds were assessed by EGM and chemical taste tests. Results EGM showed that taste thresholds at four locations on the tongue and one location on the central soft palate, 1 cm from the palatine uvula, were significantly higher in Bell's palsy patients than in controls (p<0.05). In contrast, chemical taste tests showed no significant differences in taste thresholds between the two groups (p>0.05). The severity of facial palsy did not affect taste thresholds, as determined by both EGM and chemical taste tests (p>0.05). The overall mean electrical taste thresholds on EGM were higher in younger Bell's palsy patients than in healthy subjects, with the difference at the back-right area of the tongue differing significantly (p<0.05). In older individuals, however, no significant differences in taste thresholds were observed between Bell's palsy patients and healthy subjects (p>0.05). Conclusions Electrical taste thresholds were higher in Bell's palsy patients than in controls. These differences were observed in younger, but not in older, individuals. PMID:28417103

Involvement of ATP-sensitive potassium channels and the opioid system in the anticonvulsive effect of zolpidem in mice.

PubMed

Sheikhi, Mehdi; Shirzadian, Armin; Dehdashtian, Amir; Amiri, Shayan; Ostadhadi, Sattar; Ghasemi, Mehdi; Dehpour, Ahmad Reza

2016-09-01

Zolpidem is a hypnotic medication that mainly exerts its function through activating γ-aminobutyric acid (GABA)A receptors. There is some evidence that zolpidem may have anticonvulsive effects. However, the mechanisms underlying this effect have not been elucidated yet. In the present study, we used the pentylentetrazole (PTZ)-induced generalized seizure model in mice to investigate whether zolpidem can affect seizure threshold. We also further evaluated the roles of ATP-sensitive potassium (KATP) channels as well as μ-opioid receptors in the effects of zolpidem on seizure threshold. Our data showed that zolpidem in a dose-dependent manner increased the PTZ-induced seizure threshold. The noneffective (i.e., did not significantly alter the PTZ-induced seizure threshold by itself) doses of KATP channel blocker (glibenclamide) and nonselective opioid receptor antagonist (naloxone) were able to inhibit the anticonvulsive effect of zolpidem. Additionally, noneffective doses of either KATP channel opener (cromakalim) or nonselective μ-opioid receptor agonist (morphine) in combination with a noneffective dose of zolpidem exerted a significant anticonvulsive effect on PTZ-induced seizures in mice. A combination of noneffective doses of naloxone and glibenclamide, which separately did not affect zolpidem effect on seizure threshold, inhibited the anticonvulsive effects of zolpidem. These results suggest a role for KATP channels and the opioid system, alone or in combination, in the anticonvulsive effects of zolpidem. Copyright © 2016 Elsevier Inc. All rights reserved.

Influence of surgical gloves on haptic perception thresholds.

PubMed

Hatzfeld, Christian; Dorsch, Sarah; Neupert, Carsten; Kupnik, Mario

2018-02-01

Impairment of haptic perception by surgical gloves could reduce requirements on haptic systems for surgery. While grip forces and manipulation capabilities were not impaired in previous studies, no data is available for perception thresholds. Absolute and differential thresholds (20 dB above threshold) of 24 subjects were measured for frequencies of 25 and 250 Hz with a Ψ-method. Effects of wearing a surgical glove, moisture on the contact surface and subject's experience with gloves were incorporated in a full-factorial experimental design. Absolute thresholds of 12.8 dB and -29.6 dB (means for 25 and 250 Hz, respectively) and differential thresholds of -12.6 dB and -9.5 dB agree with previous studies. A relevant effect of the frequency on absolute thresholds was found. Comparisons of glove- and no-glove-conditions did not reveal a significant mean difference. Wearing a single surgical glove does not affect absolute and differential haptic perception thresholds. Copyright © 2017 John Wiley & Sons, Ltd.

Differences in two-point discrimination and sensory threshold in the blind between braille and text reading: a pilot study.

PubMed

Noh, Ji-Woong; Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Shin, Yong-Sub; Kang, Ji-Hye; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

2015-06-01

[Purpose] This study investigated two-point discrimination (TPD) and the electrical sensory threshold of the blind to define the effect of using Braille on the tactile and electrical senses. [Subjects and Methods] Twenty-eight blind participants were divided equally into a text-reading and a Braille-reading group. We measured tactile sensory and electrical thresholds using the TPD method and a transcutaneous electrical nerve stimulator. [Results] The left palm TPD values were significantly different between the groups. The values of the electrical sensory threshold in the left hand, the electrical pain threshold in the left hand, and the electrical pain threshold in the right hand were significantly lower in the Braille group than in the text group. [Conclusion] These findings make it difficult to explain the difference in tactility between groups, excluding both palms. However, our data show that using Braille can enhance development of the sensory median nerve in the blind, particularly in terms of the electrical sensory and pain thresholds.

Differences in two-point discrimination and sensory threshold in the blind between braille and text reading: a pilot study

PubMed Central

Noh, Ji-Woong; Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Shin, Yong-Sub; Kang, Ji-Hye; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

2015-01-01

[Purpose] This study investigated two-point discrimination (TPD) and the electrical sensory threshold of the blind to define the effect of using Braille on the tactile and electrical senses. [Subjects and Methods] Twenty-eight blind participants were divided equally into a text-reading and a Braille-reading group. We measured tactile sensory and electrical thresholds using the TPD method and a transcutaneous electrical nerve stimulator. [Results] The left palm TPD values were significantly different between the groups. The values of the electrical sensory threshold in the left hand, the electrical pain threshold in the left hand, and the electrical pain threshold in the right hand were significantly lower in the Braille group than in the text group. [Conclusion] These findings make it difficult to explain the difference in tactility between groups, excluding both palms. However, our data show that using Braille can enhance development of the sensory median nerve in the blind, particularly in terms of the electrical sensory and pain thresholds. PMID:26180348

Effect of GaAs Laser at 904 nm in the Pain Threshold in Tibia and Tolerance in Deltoid Evaluated by Pressure Algometry

NASA Astrophysics Data System (ADS)

Soares, Luiz G. P.; Sato, Sidney K.; Silveira, Landulfo; Aimbire, Flávio; Moreira, Leonardo M.; Pinheiro, Antônio L. B.

2011-08-01

The use of LLLT in pain relief is a controversial issue in Physiotherapy, with the efficacy of LLLT associated to pain relief still requiring significant study. Objective. This work focuses on the evaluation of the effect of low power GaAs laser at 904 nm in pressure pain threshold and tolerance in tibia and deltoid muscle, respectively. A total of 17 subjects were divided in two groups: active and sham laser. Measurements were taken before and after laser irradiation in healthy individuals using a pressure algometry, first verifying the viability of algometry to evaluate the pain threshold and tolerance inter individuals and comparing the differences of right and left sides in the same patients, and finally evaluating the pain threshold and tolerance before and after a single laser application. Laser energy density was of 4.0 J/cm2 with power density of 137 mW/cm2. Comparing algometry values of active laser group and the sham group, the pain tolerance in the deltoid muscle did not change among groups after laser irradiation, while it was also encountered a statistically significant difference in the pain threshold in tibia when comparing the laser active and sham laser (p<0.05). It was found that the active laser was effective in maintaining the pain threshold in tibia. The effective laser action in raising the pain threshold in tibia upon healthy individuals can suggest that the laser could be applied not only as curative but also with preventive purpose.

A study on the effect of prolonged mobile phone use on pure tone audiometry thresholds of medical students of Sikkim

PubMed Central

Das, S; Chakraborty, S; Mahanta, B

2017-01-01

Introduction: Mobile phones have become indispensable for daily activities, and people are exposed to them from an early age. There is, however, concern about the harmful effect of the electromagnetic radiation emitted from the mobile phones. Objective: The objective of the study was to study the effect of mobile phone on average pure tone audiometry (PTA) threshold of the person and to study the changes in the pure tone threshold at high frequencies such as 2 kHz, 4 kHz, and 8 kHz among the students with prolonged exposure to mobile phones. Methodology: A cross-sectional study was conducted among the medical students who have been using mobile phones for the past 5 years. The effect of mobile phones on the PTA threshold in the exposed ear and the nonexposed ear was assessed. Results: The study shows that there is a significant difference in average air conduction (AC) and bone conduction (BC) hearing threshold among the exposed and the nonexposed ears (P < 0.05). A significant rise of both AC and BC threshold at individual frequencies between the exposed and the nonexposed ear is also noted in this study. Conclusion: The study conducted shows changes in the hearing threshold of the exposed ear when compared with the nonexposed ear. There are however lot of unanswered questions which provide an interesting avenue for further research. Till concrete evidence is available the only feasible way to control its exposure is to limit the duration of usage of mobile phones. PMID:28272071

The effect of systemic lipoic acid on hearing preservation after cochlear implantation via the round window approach: A guinea pig model.

PubMed

Chang, Mun Young; Gwon, Tae Mok; Lee, Ho Sun; Lee, Jun Ho; Oh, Seung Ha; Kim, Sung June; Park, Min-Hyun

2017-03-15

The present study aimed to evaluate the effects of systemic lipoic acid on hearing preservation after cochlear implantation. Twelve Dunkin-Hartley guinea pigs were randomly divided into two groups: the control group and the lipoic acid group. Animals in the lipoic acid group received lipoic acid intraperitoneally for 4 weeks. A sterilised silicone electrode-dummy was inserted through the round window to a depth of approximately 5 mm. The hearing level was measured using auditory brainstem responses (ABRs) prior to electrode-dummy insertion, and at 4 days and 1, 2, 3 and 4 weeks after electrode-dummy insertion. The threshold shift was defined as the difference between the pre-operative threshold and each of the post-operative thresholds. The cochleae were examined histologically 4 weeks after electrode-dummy insertion. Threshold shifts changed with frequency but not time. At 2kHz, ABR threshold shifts were statistically significantly lower in the lipoic acid group than the control group. At 8, 16 and 32kHz, there was no significant difference in the ABR threshold shift between the two groups. Histologic review revealed less intracochlear fibrosis along the electrode-dummy insertion site in the lipoic acid group than in the control group. The spiral ganglion cell densities of the basal, middle and apical turns were significantly higher in the lipoic acid group compared with the control group. Therefore, systemic lipoic acid administration appears to effectively preserve hearing at low frequencies in patients undergoing cochlear implantation. These effects may be attributed to the protection of spiral ganglion cells and prevention of intracochlear fibrosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Modulation by alpha-difluoromethyl-ornithine and aminoguanidine of pain threshold, morphine analgesia and tolerance.

PubMed

Lu, Gang; Su, Rui-Bin; Li, Jin; Qin, Bo-Yi

2003-10-08

The effects of alpha-difluoromethyl-ornithine (DFMO) and aminoguanidine, which might influence the metabolism of endogenous agmatine, on pain threshold, morphine analgesia and tolerance were investigated in mice. In the mouse acetic acid writhing test, intracerebroventricular (i.c.v.) injection of DFMO or aminoguanidine significantly elevated the pain threshold as indicated by a decrease in the number of writhings. DFMO or aminoguanidine obviously increased the analgesic effect of morphine in the mouse acetic acid writhing test and the mouse heat radiation tail-flick assay. These effects of DFMO and aminoguanidine were antagonized by idazoxan (3 mg/kg, i.p.), which is a selective antagonist of the imidazoline receptor. In the mouse heat radiation tail-flick assay, aminoguanidine significantly prolonged the tail-flick latency of animals, suggesting that the pain threshold was elevated. Furthermore, both DFMO and aminoguanidine enhanced morphine analgesia and inhibited acute morphine tolerance in the mouse heat radiation tail-flick assay. Neither DFMO nor aminoguanidine inhibited the activity of nitric oxide synthase in different brain areas in mice in vivo. These results indicate that the substances involved in the metabolism of endogenous agmatine could modulate the pain threshold, morphine analgesia and tolerance, indicating the possible role of endogenous agmatine in the pharmacological effects of morphine.

The relation between the effect of a subhypnotic dose of thiopental on claw pain threshold in rats and adrenalin, noradrenalin and dopamine levels.

PubMed

Aksoy, Mehmet; Ahiskalioglu, Ali; Ince, Ilker; Celik, Mine; Dostbil, Aysenur; Kuyrukluyildiz, Ufuk; Altuner, Durdu; Kurt, Nezahat; Suleyman, Halis

2015-01-01

Thiopental sodium (TPS) needs to be applied together with adrenalin in order to establish its analgesic effect in general anesthesia. We aimed to investigate the effect of TPS on the claw pain threshold in rats and evaluated its relationship with endogenous adrenalin (ADR), noradrenalin (NDR), and dopamine (DOP) levels. Intact and adrenalectomized rats were used in the experiment. Intact animals were divided into the following groups: 15 mg/kg TPS (TS), 0.3 mg/kg ADR+15 mg/kg TPS (ATS) and 0.3 mg/kg ADR alone (ADR). Adrenalectomized animals were divided into the following groups: 15 mg/kg TPS (A-TS), 0.3 mg/kg ADR+15 mg/kg TPS (A-ATS) and 0.3 mg/kg ADR alone (A-ADR). Claw pain threshold and blood ADR, NDR, and DOP levels were measured. The TS group's claw pain threshold was found low. However, the claw pain thresholds of the ATS and ADR groups increased significantly. In the A-TS group, the pain threshold decreased compared with normal, and in the A-ATS and A-ADR groups, the pain threshold increased. TPS reduced the blood ADR levels in intact rats; however, no significant changes were observed in the NDR and DOP levels. #TPS provides hyperalgesia by reducing the production of ADR in rats. The present study shows that to achieve analgesic activity, TPS needs to be applied together with ADR.

The relation between the effect of a subhypnotic dose of thiopental on claw pain threshold in rats and adrenalin, noradrenalin and dopamine levels

PubMed Central

Aksoy, Mehmet; Ahiskalioglu, Ali; Ince, Ilker; Celik, Mine; Dostbil, Aysenur; Kuyrukluyildiz, Ufuk; Altuner, Durdu; Kurt, Nezahat; Suleyman, Halis

2015-01-01

Thiopental sodium (TPS) needs to be applied together with adrenalin in order to establish its analgesic effect in general anesthesia. We aimed to investigate the effect of TPS on the claw pain threshold in rats and evaluated its relationship with endogenous adrenalin (ADR), noradrenalin (NDR), and dopamine (DOP) levels. Intact and adrenalectomized rats were used in the experiment. Intact animals were divided into the following groups: 15 mg/kg TPS (TS), 0.3 mg/kg ADR+15 mg/kg TPS (ATS) and 0.3 mg/kg ADR alone (ADR). Adrenalectomized animals were divided into the following groups: 15 mg/kg TPS (A-TS), 0.3 mg/kg ADR+15 mg/kg TPS (A-ATS) and 0.3 mg/kg ADR alone (A-ADR). Claw pain threshold and blood ADR, NDR, and DOP levels were measured. The TS group’s claw pain threshold was found low. However, the claw pain thresholds of the ATS and ADR groups increased significantly. In the A-TS group, the pain threshold decreased compared with normal, and in the A-ATS and A-ADR groups, the pain threshold increased. TPS reduced the blood ADR levels in intact rats; however, no significant changes were observed in the NDR and DOP levels. #TPS provides hyperalgesia by reducing the production of ADR in rats. The present study shows that to achieve analgesic activity, TPS needs to be applied together with ADR. PMID:26211784

Underwater temporary threshold shift in pinnipeds: effects of noise level and duration.

PubMed

Kastak, David; Southall, Brandon L; Schusterman, Ronald J; Kastak, Colleen Reichmuth

2005-11-01

Behavioral psychophysical techniques were used to evaluate the residual effects of underwater noise on the hearing sensitivity of three pinnipeds: a California sea lion (Zalophus californianus), a harbor seal (Phoca vitulina), and a northern elephant seal (Mirounga angustirostris). Temporary threshold shift (TTS), defined as the difference between auditory thresholds obtained before and after noise exposure, was assessed. The subjects were exposed to octave-band noise centered at 2500 Hz at two sound pressure levels: 80 and 95 dB SL (re: auditory threshold at 2500 Hz). Noise exposure durations were 22, 25, and 50 min. Threshold shifts were assessed at 2500 and 3530 Hz. Mean threshold shifts ranged from 2.9-12.2 dB. Full recovery of auditory sensitivity occurred within 24 h of noise exposure. Control sequences, comprising sham noise exposures, did not result in significant mean threshold shifts for any subject. Threshold shift magnitudes increased with increasing noise sound exposure level (SEL) for two of the three subjects. The results underscore the importance of including sound exposure metrics (incorporating sound pressure level and exposure duration) in order to fully assess the effects of noise on marine mammal hearing.

The effect of gabapentin on gap detection and forward masking in young and old gerbils.

PubMed

Gleich, Otto; Strutz, Jürgen

2011-01-01

Auditory temporal processing frequently appears more affected in old subjects than would be predicted by the degree of peripheral hearing loss, pointing to an age-dependent central processing deficit. In parallel, an age-dependent decline of inhibitory function has been demonstrated in the auditory pathway, suggesting a causal relationship between temporal processing and inhibition. Gabapentin has been specifically synthesized as a potential gamma-amino-butyric-acid (GABA) mimetic with the capability to cross the blood-brain barrier. Gabapentin treatment ameliorated tinnitus in a rat model and improved tinnitus annoyance in humans with acoustic trauma. Consequently, the present study evaluated the effect of gabapentin on auditory temporal processing in the gerbil model. Psychometric functions were collected for different test paradigms. (A) "Gap detection": The detection of a gap in the middle of a 800 msec broadband noise pulse was determined either at 15 or at 30 dB SL. (B) "Forward masking": The detection of a 20 msec probe stimulus following 2.5 msec after a 400 msec 40 dB SPL masker was determined with masker and probe frequency at 2.85 kHz. The effect of gabapentin was evaluated by collecting gap detection and forward masking functions before, during, and after treating gerbils with gabapentin doses of 115 or 350 mg/kg/day administered via drinking water. Data under different experimental conditions were collected for groups of 3 to 5 young (<2 years) and 6 to 10 old (>2 years) gerbils. Two-way analyses of variance for the factors age groups and treatment groups with subsequent pairwise comparisons for significant effects were used for the statistical evaluation of the data. For gap detection, mean thresholds were significantly increased in the group of old as compared with the young gerbils at 30 dB SL (young 2.0 msec; old 3.2 msec) and at 15 dB SL (young 2.9 msec; old 9.1 msec). Gabapentin had no significant effect on gap detection, and there was no significant interaction between age group and gabapentin treatment. Mean thresholds in the forward masking paradigm were significantly elevated in old (45.5 dB SPL) as compared with young (35.0 dB SPL) gerbils. Overall, gabapentin had no significant effect on masked thresholds; however, there was a significant interaction between treatment and age. Subsequent pairwise comparisons revealed no significant effect on masked thresholds in old gerbils but showed significantly elevated thresholds of young gerbils during 350 mg/kg gabapentin (38.3 dB SPL) compared with thresholds obtained in young gerbils before (32.3 dB SPL) and after (33.5 dB SPL) treatment. Gabapentin did not exert a therapeutic effect on impaired gap detection and forward masking in old gerbils. The lack of an effect of gabapentin on impaired auditory temporal processing in old gerbils and the finding of elevated masked thresholds in young gerbils can be reconciled with reports of only moderate GABAergic effects compared with other drugs (e.g., comparing elevation of GABA levels in the brain by gabapentin and vigabatrin) and effects due to binding of gabapentin to alpha-2-delta units of voltage-gated calcium channels.

Effects of Spatial Attention on Motion Discrimination are Greater in the Left than Right Visual Field

PubMed Central

Bosworth, Rain G.; Petrich, Jennifer A.; Dobkins, Karen R.

2012-01-01

In order to investigate differences in the effects of spatial attention between the left visual field (LVF) and the right visual field (RVF), we employed a full/poor attention paradigm using stimuli presented in the LVF vs. RVF. In addition, to investigate differences in the effects of spatial attention between the Dorsal and Ventral processing streams, we obtained motion thresholds (motion coherence thresholds and fine direction discrimination thresholds) and orientation thresholds, respectively. The results of this study showed negligible effects of attention on the orientation task, in either the LVF or RVF. In contrast, for both motion tasks, there was a significant effect of attention in the LVF, but not in the RVF. These data provide psychophysical evidence for greater effects of spatial attention in the LVF/right hemisphere, specifically, for motion processing in the Dorsal stream. PMID:22051893

Electroconvulsive therapy stimulus titration: Not all it seems.

PubMed

Rosenman, Stephen J

2018-05-01

To examine the provenance and implications of seizure threshold titration in electroconvulsive therapy. Titration of seizure threshold has become a virtual standard for electroconvulsive therapy. It is justified as individualisation and optimisation of the balance between efficacy and unwanted effects. Present day threshold estimation is significantly different from the 1960 studies of Cronholm and Ottosson that are its usual justification. The present form of threshold estimation is unstable and too uncertain for valid optimisation or individualisation of dose. Threshold stimulation (lowest dose that produces a seizure) has proven therapeutically ineffective, and the multiples applied to threshold to attain efficacy have never been properly investigated or standardised. The therapeutic outcomes of threshold estimation (or its multiples) have not been separated from simple dose effects. Threshold estimation does not optimise dose due to its own uncertainties and the different short-term and long-term cognitive and memory effects. Potential harms of titration have not been examined. Seizure threshold titration in electroconvulsive therapy is not a proven technique of dose optimisation. It is widely held and practiced; its benefit and harmlessness assumed but unproven. It is a prematurely settled answer to an unsettled question that discourages further enquiry. It is an example of how practices, assumed scientific, enter medicine by obscure paths.

Evaluation of Anticonvulsant, Antidepressant-, and Anxiolytic-like Effects of an Aqueous Extract from Cultured Mycelia of the Lingzhi or Reishi Medicinal Mushroom Ganoderma lucidum (Higher Basidiomycetes) in Mice.

PubMed

Socala, Katarzyna; Nieoczym, Dorota; Grzywnowicz, Krzysztof; Stefaniuk, Dawid; Wlaz, Piotr

2015-01-01

Ganoderma lucidum is a well-known medicinal mushroom with a long history of use. This study was designed to assess the anticonvulsant potential of an aqueous extract from cultured G. lucidum mycelium in 3 acute seizure models: timed intravenous pentylenetetrazole infusion, maximal electroshock seizure threshold, and 6-Hz-induced psychomotor seizure tests in mice. Moreover, antidepressant-like and anxiolytic-like effects of G. lucidum were evaluated using the forced swim test and the elevated plus maze test in mice, respectively. No changes in seizure thresholds in the intravenous pentylenetetrazole and maximal electroshock seizure threshold tests after acute treatment with G. lucidum extract (200-600 mg/kg) was observed. However, the studied extract (100-400 mg/kg) significantly increased the threshold for psychomotor seizures in the 6-Hz seizure test. In the forced swim test, G. lucidum (100-400 mg/kg) significantly reduced the duration of immobility. No anxiolytic-like or sedative effects were reported in mice pretreated with the extract (400-600 mg/kg). G. lucidum extract (50-2400 mg/kg) did not produce toxic effects in the chimney test (motor coordination) or grip-strength test (neuromuscular strength). Further studies are required to explain the neuropharmacological effects of G. lucidum and to identify its active ingredients that may affect seizure threshold, mood, or anxiety.

Audiometric analyses confirm a cochlear component, disproportional to age, in stapedial otosclerosis.

PubMed

Topsakal, Vedat; Fransen, Erik; Schmerber, Sébastien; Declau, Frank; Yung, Matthew; Gordts, Frans; Van Camp, Guy; Van de Heyning, Paul

2006-09-01

To report the preoperative audiometric profile of surgically confirmed otosclerosis. Retrospective, multicenter study. Four tertiary referral centers. One thousand sixty-four surgically confirmed patients with otosclerosis. Therapeutic ear surgery for hearing improvement. Preoperative audiometric air conduction (AC) and bone conduction (BC) hearing thresholds were obtained retrospectively for 1064 patients with otosclerosis. A cross-sectional multiple linear regression analysis was performed on audiometric data of affected ears. Influences of age and sex were analyzed and age-related typical audiograms were created. Bone conduction thresholds were corrected for Carhart effect and presbyacusis; in addition, we tested to see if separate cochlear otosclerosis component existed. Corrected thresholds were than analyzed separately for progression of cochlear otosclerosis. The study population consisted of 35% men and 65% women (mean age, 44 yr). The mean pure-tone average at 0.5, 1, and 2 kHz was 57 dB hearing level. Multiple linear regression analysis showed significant progression for all measured AC and BC thresholds. The average annual threshold deterioration for AC was 0.45 dB/yr and the annual threshold deterioration for BC was 0.37 dB/yr. The average annual gap expansion was 0.08 dB/year. The corrected BC thresholds for Carhart effect and presbyacusis remained significantly different from zero, but only showed progression at 2 kHz. The preoperative audiological profile of otosclerosis is described. There is a significant sensorineural component in patients with otosclerosis planned for stapedotomy, which is worse than age-related hearing loss by itself. Deterioration rates of AC and BC thresholds have been reported, which can be helpful in clinical practice and might also guide the characterization of allegedly different phenotypes for familial and sporadic otosclerosis.

Threshold and subthreshold Generalized Anxiety Disorder (GAD) and suicide ideation.

PubMed

Gilmour, Heather

2016-11-16

Subthreshold Generalized Anxiety Disorder (GAD) has been reported to be at least as prevalent as threshold GAD and of comparable clinical significance. It is not clear if GAD is uniquely associated with the risk of suicide, or if psychiatric comorbidity drives the association. Data from the 2012 Canadian Community Health Survey-Mental Health were used to estimate the prevalence of threshold and subthreshold GAD in the household population aged 15 or older. As well, the relationship between GAD and suicide ideation was studied. Multivariate logistic regression was used in a sample of 24,785 people to identify significant associations, while adjusting for the confounding effects of sociodemographic factors and other mental disorders. In 2012, an estimated 722,000 Canadians aged 15 or older (2.6%) met the criteria for threshold GAD; an additional 2.3% (655,000) had subthreshold GAD. For people with threshold GAD, past 12-month suicide ideation was more prevalent among men than women (32.0% versus 21.2% respectively). In multivariate models that controlled sociodemographic factors, the odds of past 12-month suicide ideation among people with either past 12-month threshold or subthreshold GAD were significantly higher than the odds for those without GAD. When psychiatric comorbidity was also controlled, associations between threshold and subthreshold GAD and suicidal ideation were attenuated, but remained significant. Threshold and subthreshold GAD affect similar percentages of the Canadian household population. This study adds to the literature that has identified an independent association between threshold GAD and suicide ideation, and demonstrates that an association is also apparent for subthreshold GAD.

Antinociceptive effects of long-acting nalbuphine decanoate after intramuscular administration to Hispaniolan Amazon parrots (Amazona ventralis).

PubMed

Sanchez-Migallon Guzman, David; Braun, Jana M; Steagall, Paulo V M; Keuler, Nicholas S; Heath, Timothy D; Krugner-Higby, Lisa A; Brown, Carolyn S; Paul-Murphy, Joanne R

2013-02-01

To evaluate the thermal antinociceptive effects and duration of action of nalbuphine decanoate after IM administration to Hispaniolan Amazon parrots (Amazona ventralis). 10 healthy adult Hispaniolan Amazon parrots of unknown sex. Nalbuphine decanoate (33.7 mg/kg) or saline (0.9% NaCl) solution was administered IM in a randomized complete crossover experimental design (periods 1 and 2). Foot withdrawal threshold to a noxious thermal stimulus was used to evaluate responses. Baseline thermal withdrawal threshold was recorded 1 hour before drug or saline solution administration, and thermal foot withdrawal threshold measurements were repeated 1, 2, 3, 6, 12, 24, 48, and 72 hours after drug administration. Nalbuphine decanoate administered IM at a dose of 33.7 mg/kg significantly increased thermal foot withdrawal threshold, compared with results after administration of saline solution during period 2, and also caused a significant change in withdrawal threshold for up to 12 hours, compared with baseline values. Nalbuphine decanoate increased the foot withdrawal threshold to a noxious thermal stimulus in Hispaniolan Amazon parrots for up to 12 hours and provided a longer duration of action than has been reported for other nalbuphine formulations. Further studies with other types of nociceptive stimulation, dosages, and dosing intervals as well as clinical trials are needed to fully evaluate the analgesic effects of nalbuphine decanoate in psittacine birds.

Octave-Band Thresholds for Modeled Reverberant Fields

NASA Technical Reports Server (NTRS)

Begault, Durand R.; Wenzel, Elizabeth M.; Tran, Laura L.; Anderson, Mark R.; Trejo, Leonard J. (Technical Monitor)

1998-01-01

Auditory thresholds for 10 subjects were obtained for speech stimuli reverberation. The reverberation was produced and manipulated by 3-D audio modeling based on an actual room. The independent variables were octave-band-filtering (bypassed, 0.25 - 2.0 kHz Fc) and reverberation time (0.2- 1.1 sec). An ANOVA revealed significant effects (threshold range: -19 to -35 dB re 60 dB SRL).

Effect of difference in occlusal contact area of mandibular free-end edentulous area implants on periodontal mechanosensitive threshold of adjacent premolars.

PubMed

Terauchi, Rie; Arai, Korenori; Tanaka, Masahiro; Kawazoe, Takayoshi; Baba, Shunsuke

2015-01-01

Implant treatment is believed to cause minimal invasion of remaining teeth. However, few studies have examined teeth adjacent to an implant region. Therefore, this study investigated the effect of occlusal contact size of implants on the periodontal mechanosensitive threshold of adjacent premolars. A cross-sectional study design was adopted. The Department of Oral Implantology, Osaka Dental University, was the setting where patients underwent implant treatment in the mandibular free-end edentulous area. The study population comprised of 87 patients (109 teeth) who underwent follow-up observation for at least 3 years following implant superstructure placement. As variables, age, sex, duration following superstructure placement, presence or absence of dental pulp, occlusal contact area, and periodontal mechanosensitive threshold were considered. The occlusal contact area was measured using Blue Silicone(®)and Bite Eye BE-I(®). Periodontal mechanosensitive threshold were measured using von Frey hair. As quantitative variables for periodontal mechanosensitive threshold, we divided subjects into two groups: normal (≤5 g) and high (≥5.1 g). For statistical analysis, we compared the two groups for the sensation thresholds using the Chi square test for categorical data and the Mann-Whitney U test for continuous volume data. For variables in which a significant difference was noted, we calculated the odds ratio (95 % confidence interval) and the effective dose. There were 93 teeth in the normal group and 16 teeth in the high group based on periodontal mechanosensitive threshold. Comparison of the two groups indicated no significant differences associated with age, sex, duration following superstructure placement, or presence or absence of dental pulp. A significant difference was noted with regard to occlusal contact area, with several high group subjects belonging to the small contact group (odds ratio: 4.75 [1.42-15.87]; effective dose: 0.29). The results of this study suggest an association between implant occlusal contact area and the periodontal mechanosensitive threshold of adjacent premolars. Smaller occlusal contact application resulted in an increased threshold. It appears that prosthodontic treatment should aim not only to improve occlusal function but also to maintain oromandibular function with regard to the preservation of remaining teeth.

Association of daily asthma emergency department visits and hospital admissions with ambient air pollutants among the pediatric Medicaid population in Detroit: time-series and time-stratified case-crossover analyses with threshold effects.

PubMed

Li, Shi; Batterman, Stuart; Wasilevich, Elizabeth; Wahl, Robert; Wirth, Julie; Su, Feng-Chiao; Mukherjee, Bhramar

2011-11-01

Asthma morbidity has been associated with ambient air pollutants in time-series and case-crossover studies. In such study designs, threshold effects of air pollutants on asthma outcomes have been relatively unexplored, which are of potential interest for exploring concentration-response relationships. This study analyzes daily data on the asthma morbidity experienced by the pediatric Medicaid population (ages 2-18 years) of Detroit, Michigan and concentrations of pollutants fine particles (PM2.5), CO, NO2 and SO2 for the 2004-2006 period, using both time-series and case-crossover designs. We use a simple, testable and readily implementable profile likelihood-based approach to estimate threshold parameters in both designs. Evidence of significant increases in daily acute asthma events was found for SO2 and PM2.5, and a significant threshold effect was estimated for PM2.5 at 13 and 11 μg m(-3) using generalized additive models and conditional logistic regression models, respectively. Stronger effect sizes above the threshold were typically noted compared to standard linear relationship, e.g., in the time series analysis, an interquartile range increase (9.2 μg m(-3)) in PM2.5 (5-day-moving average) had a risk ratio of 1.030 (95% CI: 1.001, 1.061) in the generalized additive models, and 1.066 (95% CI: 1.031, 1.102) in the threshold generalized additive models. The corresponding estimates for the case-crossover design were 1.039 (95% CI: 1.013, 1.066) in the conditional logistic regression, and 1.054 (95% CI: 1.023, 1.086) in the threshold conditional logistic regression. This study indicates that the associations of SO2 and PM2.5 concentrations with asthma emergency department visits and hospitalizations, as well as the estimated PM2.5 threshold were fairly consistent across time-series and case-crossover analyses, and suggests that effect estimates based on linear models (without thresholds) may underestimate the true risk. Copyright © 2011 Elsevier Inc. All rights reserved.

A Phase II, Randomized, Double-Blind, Placebo Controlled, Dose-Response Trial of the Melatonin Effect on the Pain Threshold of Healthy Subjects

PubMed Central

Stefani, Luciana Cadore; Muller, Suzana; Torres, Iraci L. S.; Razzolini, Bruna; Rozisky, Joanna R.; Fregni, Felipe; Markus, Regina; Caumo, Wolnei

2013-01-01

Background Previous studies have suggested that melatonin may produce antinociception through peripheral and central mechanisms. Based on the preliminary encouraging results of studies of the effects of melatonin on pain modulation, the important question has been raised of whether there is a dose relationship in humans of melatonin on pain modulation. Objective The objective was to evaluate the analgesic dose response of the effects of melatonin on pressure and heat pain threshold and tolerance and the sedative effects. Methods Sixty-one healthy subjects aged 19 to 47 y were randomized into one of four groups: placebo, 0.05 mg/kg sublingual melatonin, 0.15 mg/kg sublingual melatonin or 0.25 mg/kg sublingual melatonin. We determine the pressure pain threshold (PPT) and the pressure pain tolerance (PPTo). Quantitative sensory testing (QST) was used to measure the heat pain threshold (HPT) and the heat pain tolerance (HPTo). Sedation was assessed with a visual analogue scale and bispectral analysis. Results Serum plasma melatonin levels were directly proportional to the melatonin doses given to each subject. We observed a significant effect associated with dose group. Post hoc analysis indicated significant differences between the placebo vs. the intermediate (0.15 mg/kg) and the highest (0.25 mg/kg) melatonin doses for all pain threshold and sedation level tests. A linear regression model indicated a significant association between the serum melatonin concentrations and changes in pain threshold and pain tolerance (R2 = 0.492 for HPT, R2 = 0.538 for PPT, R2 = 0.558 for HPTo and R2 = 0.584 for PPTo). Conclusions The present data indicate that sublingual melatonin exerts well-defined dose-dependent antinociceptive activity. There is a correlation between the plasma melatonin drug concentration and acute changes in the pain threshold. These results provide additional support for the investigation of melatonin as an analgesic agent. Brazilian Clinical Trials Registry (ReBec): (U1111-1123-5109). IRB: Research Ethics Committee at the Hospital de Clínicas de Porto Alegre. PMID:25947930

Effects of programming threshold and maplaw settings on acoustic thresholds and speech discrimination with the MED-EL COMBI 40+ cochlear implant.

PubMed

Boyd, Paul J

2006-12-01

The principal task in the programming of a cochlear implant (CI) speech processor is the setting of the electrical dynamic range (output) for each electrode, to ensure that a comfortable loudness percept is obtained for a range of input levels. This typically involves separate psychophysical measurement of electrical threshold ([theta] e) and upper tolerance levels using short current bursts generated by the fitting software. Anecdotal clinical experience and some experimental studies suggest that the measurement of [theta]e is relatively unimportant and that the setting of upper tolerance limits is more critical for processor programming. The present study aims to test this hypothesis and examines in detail how acoustic thresholds and speech recognition are affected by setting of the lower limit of the output ("Programming threshold" or "PT") to understand better the influence of this parameter and how it interacts with certain other programming parameters. Test programs (maps) were generated with PT set to artificially high and low values and tested on users of the MED-EL COMBI 40+ CI system. Acoustic thresholds and speech recognition scores (sentence tests) were measured for each of the test maps. Acoustic thresholds were also measured using maps with a range of output compression functions ("maplaws"). In addition, subjective reports were recorded regarding the presence of "background threshold stimulation" which is occasionally reported by CI users if PT is set to relatively high values when using the CIS strategy. Manipulation of PT was found to have very little effect. Setting PT to minimum produced a mean 5 dB (S.D. = 6.25) increase in acoustic thresholds, relative to thresholds with PT set normally, and had no statistically significant effect on speech recognition scores on a sentence test. On the other hand, maplaw setting was found to have a significant effect on acoustic thresholds (raised as maplaw is made more linear), which provides some theoretical explanation as to why PT has little effect when using the default maplaw of c = 500. Subjective reports of background threshold stimulation showed that most users could perceive a relatively loud auditory percept, in the absence of microphone input, when PT was set to double the behaviorally measured electrical thresholds ([theta]e), but that this produced little intrusion when microphone input was present. The results of these investigations have direct clinical relevance, showing that setting of PT is indeed relatively unimportant in terms of speech discrimination, but that it is worth ensuring that PT is not set excessively high, as this can produce distracting background stimulation. Indeed, it may even be set to minimum values without deleterious effect.

Hydrogen peroxide preferentially activates capsaicin‐sensitive high threshold afferents via TRPA1 channels in the guinea pig bladder

PubMed Central

Nicholas, S; Yuan, S Y; Brookes, S J H; Spencer, N J

2016-01-01

Background and Purpose There is increasing evidence suggesting that ROS play a major pathological role in bladder dysfunction induced by bladder inflammation and/or obstruction. The aim of this study was to determine the effect of H2O2 on different types of bladder afferents and its mechanism of action on sensory neurons in the guinea pig bladder. Experimental Approach ‘Close‐to‐target’ single unit extracellular recordings were made from fine branches of pelvic nerves entering the guinea pig bladder, in flat sheet preparations, in vitro. Key Results H2O2 (300–1000 μM) preferentially and potently activated capsaicin‐sensitive high threshold afferents but not low threshold stretch‐sensitive afferents, which were only activated by significantly higher concentrations of hydrogen peroxide. The TRPV1 channel agonist, capsaicin, excited 86% of high threshold afferents. The TRPA1 channel agonist, allyl isothiocyanate and the TRPM8 channel agonist, icilin activated 72% and 47% of capsaicin‐sensitive high threshold afferents respectively. The TRPA1 channel antagonist, HC‐030031, but not the TRPV1 channel antagonist, capsazepine or the TRPM8 channel antagonist, N‐(2‐aminoethyl)‐N‐[[3‐methoxy‐4‐(phenylmethoxy)phenyl]methyl]thiophene‐2‐carboxamide, significantly inhibited the H2O2‐induced activation of high threshold afferents. Dimethylthiourea and deferoxamine did not significantly change the effect of H2O2 on high threshold afferents. Conclusions and Implications The findings show that H2O2, in the concentration range detected in inflammation or reperfusion after ischaemia, evoked long‐lasting activation of the majority of capsaicin‐sensitive high threshold afferents, but not low threshold stretch‐sensitive afferents. The data suggest that the TRPA1 channels located on these capsaicin‐sensitive afferent fibres are probable targets of ROS released during oxidative stress. PMID:27792844

Abnormal pain perception in patients with Multiple System Atrophy.

PubMed

Ory-Magne, F; Pellaprat, J; Harroch, E; Galitzsky, M; Rousseau, V; Pavy-Le Traon, A; Rascol, O; Gerdelat, A; Brefel-Courbon, C

2018-03-01

Patients with Parkinson's disease or Multiple System Atrophy frequently experience painful sensations. The few studies investigating pain mechanisms in Multiple System Atrophy patients have reported contradictory results. In our study, we compared pain thresholds in Multiple System Atrophy and Parkinson's disease patients and healthy controls and evaluated the effect of l-DOPA on pain thresholds. We assessed subjective and objective pain thresholds (using a thermotest and RIII reflex), and pain tolerance in OFF and ON conditions, clinical pain, motor and psychological evaluation. Pain was reported in 78.6% of Multiple System Atrophy patients and in 37.5% of Parkinson's disease patients. In the OFF condition, subjective and objective pain thresholds were significantly lower in Multiple System Atrophy patients than in healthy controls (43.8 °C ± 1.3 vs 45.7 °C ± 0.8; p = 0.0005 and 7.4 mA ± 3.8 vs 13.7 mA ± 2.8; p = 0.002, respectively). They were also significantly reduced in Multiple System Atrophy compared to Parkinson's disease patients. No significant difference was found in pain tolerance for the 3 groups and in the effect of l-DOPA on pain thresholds in Multiple System Atrophy and Parkinson's disease patients. In the ON condition, pain tolerance tended to be reduced in Multiple System Atrophy versus Parkinson's disease patients (p = 0.05). Multiple System Atrophy patients had an increase in pain perception compared to Parkinson's disease patients and healthy controls. The l-DOPA effect was similar for pain thresholds in Multiple System Atrophy and Parkinson's disease patients, but tended to worsen pain tolerance in Multiple System Atrophy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of stimulus intensity on the efficacy and safety of twice-weekly, bilateral electroconvulsive therapy (ECT) combined with antipsychotics in acute mania: a randomised controlled trial.

PubMed

Mohan, Titus S P; Tharyan, Prathap; Alexander, Jacob; Raveendran, Nirmal S

2009-03-01

To examine differences in speed of improvement and remission in people with mania undergoing bilateral, brief-pulse, twice-weekly electroconvulsive therapy (ECT) at stimulus intensities administered just above and 2.5 times their individually titrated seizure threshold. Consecutive, eligible subjects with mania, prescribed ECT, were randomised to receive treatments at stimulus doses either just above or 2.5 times their individually titrated seizure thresholds. Main outcomes were the speed of improvement and remission as measured by the Young Mania Rating Scale (YMRS) and the Clinical Global Impressions-Improvement scale (CGI-I) and cognitive side effects assessed by the Mini-Mental State Exam, the Wechsler Memory Scale, and a scale for autobiographical memory. A total of 24/26 subjects (92.3%) given threshold ECT and 22/24 subjects (91.7%) given suprathreshold ECT were significantly improved [CGI = 2; odds ratio (OR) = 1.1, 95% confidence interval (CI): 0.1-8.4; p = 1.0] at the end of ECT. A total of 88% of the sample had remitted [YMRS < 10; threshold 23/26 (88.5%) versus suprathreshold 21/24 (87.5%)], with no significant differences between interventions (OR = 1.1, 95% CI: 0.2- 6.0; p = 1.0). The interventions did not differ significantly in the time or number of ECT treatments required for improvement or remission. Both interventions were equally safe. Bilateral, twice-weekly ECT delivered at stimulus intensities just above individually titrated seizure threshold was as effective and safe as ECT administered at stimulus intensities 2.5 times seizure threshold in rapidly resolving the symptoms of acute mania.

Effects of visual erotic stimulation on vibrotactile detection thresholds in men.

PubMed

Jiao, Chuanshu; Knight, Peter K; Weerakoon, Patricia; Turman, A Bulent

2007-12-01

This study examined the effects of sexual arousal on vibration detection thresholds in the right index finger of 30 healthy, heterosexual males who reported no sexual dysfunction. Vibrotactile detection thresholds at frequencies of 30, 60, and 100 Hz were assessed before and after watching erotic and control videos using a forced-choice, staircase method. A mechanical stimulator was used to produce the vibratory stimulus. Results were analyzed using repeated measures analysis of variance. After watching the erotic video, the vibrotactile detection thresholds at 30, 60, and 100 Hz were significantly reduced (p < .01). No changes in thresholds were detected at any frequency following exposure to the non-erotic stimulus. The results show that sexual arousal resulted in an increase in vibrotactile sensitivity to low frequency stimuli in the index finger of sexually functional men.

Cervical joint position sense in neck pain. Immediate effects of muscle vibration versus mental training interventions: a RCT.

PubMed

Beinert, K; Preiss, S; Huber, M; Taube, W

2015-12-01

Impaired cervical joint position sense is a feature of chronic neck pain and is commonly argued to rely on abnormal cervical input. If true, muscle vibration, altering afferent input, but not mental interventions, should have an effect on head repositioning acuity and neck pain perception. The aim of the present study was to determine the short-term effects of neck muscle vibration, motor imagery, and action observation on cervical joint position sense and pressure pain threshold in people with chronic neck pain. Forty-five blinded participants with neck pain received concealed allocation and were randomized in three treatment groups. A blinded assessor performed pre- and post-test measurement. Patients were recruited from secondary outpatient clinics in the southwest of Germany. Chronic, non specific neck pain patients without arm pain were recruited for this study. A single intervention session of 5 minutes was delivered to each blinded participant. Patients were either allocated to one of the following three interventions: (1) neck muscle vibration; (2) motor imagery; (3) action observation. Primary outcomes were cervical joint position sense acuity and pressure pain threshold. Repeated measures ANOVAs were used to evaluate differences between groups and subjects. Repositioning acuity displayed significant time effects for vibration, motor imagery, and action observation (all P<0.05), but revealed no time*group effect. Pressure pain threshold demonstrated a time*group effect (P=0.042) as only vibration significantly increased pressure pain threshold (P=0.01). Although motor imagery and action observation did not modulate proprioceptive, afferent input, they nevertheless improved cervical joint position sense acuity. This indicates that, against the common opinion, changes in proprioceptive input are not prerequisite to improve joint repositioning performance. However, the short-term applications of these cognitive treatments had no effect on pressure pain thresholds, whereas vibration reduced pressure pain thresholds. This implies different underlying mechanisms after vibration and mental training. Mental interventions were effective in improving cervical joint position sense and are easy to integrate in rehabilitation regimes. Neck muscle vibration is effective in improving cervical joint position sense and pressure pain thresholds within 5 minutes of application.

Polarization properties of below-threshold harmonics from aligned molecules H2+ in linearly polarized laser fields.

PubMed

Dong, Fulong; Tian, Yiqun; Yu, Shujuan; Wang, Shang; Yang, Shiping; Chen, Yanjun

2015-07-13

We investigate the polarization properties of below-threshold harmonics from aligned molecules in linearly polarized laser fields numerically and analytically. We focus on lower-order harmonics (LOHs). Our simulations show that the ellipticity of below-threshold LOHs depends strongly on the orientation angle and differs significantly for different harmonic orders. Our analysis reveals that this LOH ellipticity is closely associated with resonance effects and the axis symmetry of the molecule. These results shed light on the complex generation mechanism of below-threshold harmonics from aligned molecules.

ABT-627, an endothelin ET(A) receptor-selective antagonist, attenuates tactile allodynia in a diabetic rat model of neuropathic pain.

PubMed

Jarvis, M F; Wessale, J L; Zhu, C Z; Lynch, J J; Dayton, B D; Calzadilla, S V; Padley, R J; Opgenorth, T J; Kowaluk, E A

2000-01-24

Tactile allodynia, the enhanced perception of pain in response to normally non-painful stimulation, represents a common complication of diabetic neuropathy. The activation of endothelin ET(A) receptors has been implicated in diabetes-induced reductions in peripheral neurovascularization and concomitant endoneurial hypoxia. Endothelin receptor activation has also been shown to alter the peripheral and central processing of nociceptive information. The present study was conducted to evaluate the antinociceptive effects of the novel endothelin ET(A) receptor-selective antagonist, 2R-(4-methoxyphenyl)-4S-(1,3-benzodioxol-5-yl)-1-(N, N-di(n-butyl)aminocarbonyl-methyl)-pyrrolidine-3R-carboxylic acid (ABT-627), in the streptozotocin-induced diabetic rat model of neuropathic pain. Rats were injected with 75 mg/kg streptozotocin (i. p.), and drug effects were assessed 8-12 weeks following streptozotocin treatment to allow for stabilization of blood glucose levels (>/=240 mg/dl) and tactile allodynia thresholds (

Effects of N-acetylcysteine on noise-induced temporary threshold shift and temporary emission shift

NASA Astrophysics Data System (ADS)

Robinette, Martin

2004-05-01

Animal research has shown that antioxidants can provide significant protection to the cochlea from traumatic noise exposure with some benefit when given after the exposure. Similar results in humans would have a significant impact on both prevention and treatment of noise-induced hearing loss. The current study evaluates the effectiveness of N-acetylcysteine (NAC) on temporary threshold shift (TTS) by using both behavioral and physiological measures. Sixteen healthy, normal-hearing subjects were given NAC or a placebo prior to exposure to a 10-min, 102-dB narrow-band noise, centered at 2 kHz. This exposure was designed to induce a 10-15-dB TTS. Following the noise exposure, pure-tone thresholds (Bekesy) and transient-evoked otoacoustic emissions (TEOAE) were measured for 60 min to monitor the effects of NAC on TTS recovery. Postexposure measures were compared to baseline data. [Work supported by American BioHealth Group.

The earth is flat (p > 0.05): significance thresholds and the crisis of unreplicable research.

PubMed

Amrhein, Valentin; Korner-Nievergelt, Fränzi; Roth, Tobias

2017-01-01

The widespread use of 'statistical significance' as a license for making a claim of a scientific finding leads to considerable distortion of the scientific process (according to the American Statistical Association). We review why degrading p -values into 'significant' and 'nonsignificant' contributes to making studies irreproducible, or to making them seem irreproducible. A major problem is that we tend to take small p -values at face value, but mistrust results with larger p -values. In either case, p -values tell little about reliability of research, because they are hardly replicable even if an alternative hypothesis is true. Also significance ( p  ≤ 0.05) is hardly replicable: at a good statistical power of 80%, two studies will be 'conflicting', meaning that one is significant and the other is not, in one third of the cases if there is a true effect. A replication can therefore not be interpreted as having failed only because it is nonsignificant. Many apparent replication failures may thus reflect faulty judgment based on significance thresholds rather than a crisis of unreplicable research. Reliable conclusions on replicability and practical importance of a finding can only be drawn using cumulative evidence from multiple independent studies. However, applying significance thresholds makes cumulative knowledge unreliable. One reason is that with anything but ideal statistical power, significant effect sizes will be biased upwards. Interpreting inflated significant results while ignoring nonsignificant results will thus lead to wrong conclusions. But current incentives to hunt for significance lead to selective reporting and to publication bias against nonsignificant findings. Data dredging, p -hacking, and publication bias should be addressed by removing fixed significance thresholds. Consistent with the recommendations of the late Ronald Fisher, p -values should be interpreted as graded measures of the strength of evidence against the null hypothesis. Also larger p -values offer some evidence against the null hypothesis, and they cannot be interpreted as supporting the null hypothesis, falsely concluding that 'there is no effect'. Information on possible true effect sizes that are compatible with the data must be obtained from the point estimate, e.g., from a sample average, and from the interval estimate, such as a confidence interval. We review how confusion about interpretation of larger p -values can be traced back to historical disputes among the founders of modern statistics. We further discuss potential arguments against removing significance thresholds, for example that decision rules should rather be more stringent, that sample sizes could decrease, or that p -values should better be completely abandoned. We conclude that whatever method of statistical inference we use, dichotomous threshold thinking must give way to non-automated informed judgment.

Determination of optimum threshold values for EMG time domain features; a multi-dataset investigation

NASA Astrophysics Data System (ADS)

Nlandu Kamavuako, Ernest; Scheme, Erik Justin; Englehart, Kevin Brian

2016-08-01

Objective. For over two decades, Hudgins’ set of time domain features have extensively been applied for classification of hand motions. The calculation of slope sign change and zero crossing features uses a threshold to attenuate the effect of background noise. However, there is no consensus on the optimum threshold value. In this study, we investigate for the first time the effect of threshold selection on the feature space and classification accuracy using multiple datasets. Approach. In the first part, four datasets were used, and classification error (CE), separability index, scatter matrix separability criterion, and cardinality of the features were used as performance measures. In the second part, data from eight classes were collected during two separate days with two days in between from eight able-bodied subjects. The threshold for each feature was computed as a factor (R = 0:0.01:4) times the average root mean square of data during rest. For each day, we quantified CE for R = 0 (CEr0) and minimum error (CEbest). Moreover, a cross day threshold validation was applied where, for example, CE of day two (CEodt) is computed based on optimum threshold from day one and vice versa. Finally, we quantified the effect of the threshold when using training data from one day and test data of the other. Main results. All performance metrics generally degraded with increasing threshold values. On average, CEbest (5.26 ± 2.42%) was significantly better than CEr0 (7.51 ± 2.41%, P = 0.018), and CEodt (7.50 ± 2.50%, P = 0.021). During the two-fold validation between days, CEbest performed similar to CEr0. Interestingly, when using the threshold values optimized per subject from day one and day two respectively, on the cross-days classification, the performance decreased. Significance. We have demonstrated that threshold value has a strong impact on the feature space and that an optimum threshold can be quantified. However, this optimum threshold is highly data and subject driven and thus do not generalize well. There is a strong evidence that R = 0 provides a good trade-off between system performance and generalization. These findings are important for practical use of pattern recognition based myoelectric control.

Aging deteriorated perception of urge-to-cough without changing cough reflex threshold to citric acid in female never-smokers.

PubMed

Ebihara, Satoru; Ebihara, Takae; Kanezaki, Masashi; Gui, Peijun; Yamasaki, Miyako; Arai, Hiroyuki; Kohzuki, Masahiro

2011-06-28

The effect of aging on the cognitive aspect of cough has not been studied yet. The purpose of this study is to investigate the aging effect on the perception of urge-to-cough in healthy individuals. Fourteen young, female, healthy never-smokers were recruited via public postings. Twelve elderly female healthy never-smokers were recruited from a nursing home residence. The cough reflex threshold and the urge-to-cough were evaluated by inhalation of citric acid. The cough reflex sensitivities were defined as the lowest concentration of citric acid that elicited two or more coughs (C2) and five or more coughs (C5). The urge-to-cough was evaluated using a modified the Borg scale. There was no significant difference in the cough reflex threshold to citric acid between young and elderly subjects. The urge-to-cough scores at the concentration of C2 and C5 were significantly smaller in the elderly than young subjects. The urge-to-cough log-log slope in elderly subjects (0.73 ± 0.71 point · L/g) was significantly gentler than those of young subjects (1.35 ± 0.53 point · L/g, p < 0.01). There were no significant differences in the urge-to-cough threshold estimated between young and elderly subjects. The cough reflex threshold did not differ between young and elderly subjects whereas cognition of urge-to-cough was significantly decreased in elderly subjects in female never-smokers. Objective monitoring of cough might be important in the elderly people.

Pollutant threshold concentration determination in marine ecosystems using an ecological interaction endpoint.

PubMed

Wang, Changyou; Liang, Shengkang; Guo, Wenting; Yu, Hua; Xing, Wenhui

2015-09-01

The threshold concentrations of pollutants are determined by extrapolating single-species effect data to community-level effects. This assumes the most sensitive endpoint of the life cycle of individuals and the species sensitivity distribution from single-species toxic effect tests, thus, ignoring the ecological interactions. The uncertainties due to this extrapolation can be partially overcome using the equilibrium point of a customized ecosystem. This method incorporates ecological interactions and integrates the effects on growth, survival, and ingestion into a single effect measure, the equilibrium point excursion in the customized ecosystem, in order to describe the toxic effects on plankton. A case study showed that the threshold concentration of copper calculated with the endpoint of the equilibrium point was 10 μg L(-1), which is significantly different from the threshold calculated with a single-species endpoint. The endpoint calculated using this method provides a more relevant measure of the ecological impact than any single individual-level endpoint. Copyright © 2015 Elsevier Ltd. All rights reserved.

Laparoscopic Cholecystectomy for Gallbladder Calculosis in Fibromyalgia Patients: Impact on Musculoskeletal Pain, Somatic Hyperalgesia and Central Sensitization

PubMed Central

Costantini, Raffaele; Affaitati, Giannapia; Massimini, Francesca; Tana, Claudio; Innocenti, Paolo; Giamberardino, Maria Adele

2016-01-01

Fibromyalgia, a chronic syndrome of diffuse musculoskeletal pain and somatic hyperalgesia from central sensitization, is very often comorbid with visceral pain conditions. In fibromyalgia patients with gallbladder calculosis, this study assessed the short and long-term impact of laparoscopic cholecystectomy on fibromyalgia pain symptoms. Fibromyalgia pain (VAS scale) and pain thresholds in tender points and control areas (skin, subcutis and muscle) were evaluated 1week before (basis) and 1week, 1,3,6 and 12months after laparoscopic cholecystectomy in fibromyalgia patients with symptomatic calculosis (n = 31) vs calculosis patients without fibromyalgia (n. 26) and at comparable time points in fibromyalgia patients not undergoing cholecystectomy, with symptomatic (n = 27) and asymptomatic (n = 28) calculosis, and no calculosis (n = 30). At basis, fibromyalgia+symptomatic calculosis patients presented a significant linear correlation between the number of previously experienced biliary colics and fibromyalgia pain (direct) and muscle thresholds (inverse)(p<0.0001). After cholecystectomy, fibromyalgia pain significantly increased and all thresholds significantly decreased at 1week and 1month (1-way ANOVA, p<0.01-p<0.001), the decrease in muscle thresholds correlating linearly with the peak postoperative pain at surgery site (p<0.003-p<0.0001). Fibromyalgia pain and thresholds returned to preoperative values at 3months, then pain significantly decreased and thresholds significantly increased at 6 and 12months (p<0.05-p<0.0001). Over the same 12-month period: in non-fibromyalgia patients undergoing cholecystectomy thresholds did not change; in all other fibromyalgia groups not undergoing cholecystectomy fibromyalgia pain and thresholds remained stable, except in fibromyalgia+symptomatic calculosis at 12months when pain significantly increased and muscle thresholds significantly decreased (p<0.05-p<0.0001). The results of the study show that biliary colics from gallbladder calculosis represent an exacerbating factor for fibromyalgia symptoms and that laparoscopic cholecystectomy produces only a transitory worsening of these symptoms, largely compensated by the long-term improvement/desensitization due to gallbladder removal. This study provides new insights into the role of visceral pain comorbidities and the effects of their treatment on fibromyalgia pain/hypersensitivity. PMID:27081848

Laparoscopic Cholecystectomy for Gallbladder Calculosis in Fibromyalgia Patients: Impact on Musculoskeletal Pain, Somatic Hyperalgesia and Central Sensitization.

PubMed

Costantini, Raffaele; Affaitati, Giannapia; Massimini, Francesca; Tana, Claudio; Innocenti, Paolo; Giamberardino, Maria Adele

2016-01-01

Fibromyalgia, a chronic syndrome of diffuse musculoskeletal pain and somatic hyperalgesia from central sensitization, is very often comorbid with visceral pain conditions. In fibromyalgia patients with gallbladder calculosis, this study assessed the short and long-term impact of laparoscopic cholecystectomy on fibromyalgia pain symptoms. Fibromyalgia pain (VAS scale) and pain thresholds in tender points and control areas (skin, subcutis and muscle) were evaluated 1week before (basis) and 1week, 1,3,6 and 12months after laparoscopic cholecystectomy in fibromyalgia patients with symptomatic calculosis (n = 31) vs calculosis patients without fibromyalgia (n. 26) and at comparable time points in fibromyalgia patients not undergoing cholecystectomy, with symptomatic (n = 27) and asymptomatic (n = 28) calculosis, and no calculosis (n = 30). At basis, fibromyalgia+symptomatic calculosis patients presented a significant linear correlation between the number of previously experienced biliary colics and fibromyalgia pain (direct) and muscle thresholds (inverse)(p<0.0001). After cholecystectomy, fibromyalgia pain significantly increased and all thresholds significantly decreased at 1week and 1month (1-way ANOVA, p<0.01-p<0.001), the decrease in muscle thresholds correlating linearly with the peak postoperative pain at surgery site (p<0.003-p<0.0001). Fibromyalgia pain and thresholds returned to preoperative values at 3months, then pain significantly decreased and thresholds significantly increased at 6 and 12months (p<0.05-p<0.0001). Over the same 12-month period: in non-fibromyalgia patients undergoing cholecystectomy thresholds did not change; in all other fibromyalgia groups not undergoing cholecystectomy fibromyalgia pain and thresholds remained stable, except in fibromyalgia+symptomatic calculosis at 12months when pain significantly increased and muscle thresholds significantly decreased (p<0.05-p<0.0001). The results of the study show that biliary colics from gallbladder calculosis represent an exacerbating factor for fibromyalgia symptoms and that laparoscopic cholecystectomy produces only a transitory worsening of these symptoms, largely compensated by the long-term improvement/desensitization due to gallbladder removal. This study provides new insights into the role of visceral pain comorbidities and the effects of their treatment on fibromyalgia pain/hypersensitivity.

Vibrotactile perception and effects of short-term exposure to hand-arm vibration.

PubMed

Burström, Lage; Lundström, Ronnie; Hagberg, Mats; Nilsson, Tohr

2009-07-01

This study clarifies whether the established frequency weighting procedure for evaluating exposure to hand-transmitted vibration can effectively evaluate the temporary changes in vibrotactile perception thresholds due to pre-exposure to vibration. In addition, this study investigates the relationship between changes of the vibrotactile perception thresholds and the normalized energy-equivalent frequency-weighted acceleration. The fingers of 10 healthy subjects, five male and five female, were exposed to vibration under 16 conditions with a combination of different frequencies, intensities, and exposure times. The vibration frequencies were 31.5 and 125 Hz and exposure lasted between 2 and 16 min. According to International Organization for Standardization (ISO) 5349-1, the energy-equivalent frequency-weighted acceleration for the experimental time of 16 min is 2.5 or 5.0 m s(-2) root-mean-square, corresponding to a 8-h equivalent acceleration, A(8), of approximately 0.5 and 0.9 m s(-2), respectively. A measure of the vibrotactile perception thresholds was conducted before the different exposures to vibration. Immediately after the vibration exposure, the acute effect was measured continuously on the exposed index finger for the first 75 s, followed by 30 s of measures every minute for a maximum of 10 min. If the subject's thresholds had not recovered, the measures continued for a maximum of 30 min with measurements taken every 5 min. Pre-exposure to vibration significantly influenced vibrotactile thresholds. This study concludes that the influence on the thresholds depends on the frequency of the vibration stimuli. Increased equivalent frequency-weighted acceleration resulted in a significant change in threshold, but the thresholds were unaffected when changes in the vibration magnitude were expressed as the frequency-weighted acceleration or the unweighted acceleration. Moreover, the frequency of the pre-vibration exposure significantly influenced (up to 25 min after exposure) recovery time of the vibrotactile thresholds. This study shows that the frequency weighting procedure in ISO 5349-1 is unable to predict the produced acute changes in the vibrotactile perception. Moreover, the results imply that the calculation of the 'energy-equivalent' frequency-weighted acceleration does not reflect the acute changes of the vibration perception thresholds due to pre-exposure to vibration. Furthermore, when testing for the vibrotactile thresholds, exposure to vibration on the day of a test might influence the results. Until further knowledge is obtained, the previous practice of 3 h avoidance of vibration exposure before assessment is recommended.

Electrophysiological gap detection thresholds: effects of age and comparison with a behavioral measure.

PubMed

Palmer, Shannon B; Musiek, Frank E

2014-01-01

Temporal processing ability has been linked to speech understanding ability and older adults often complain of difficulty understanding speech in difficult listening situations. Temporal processing can be evaluated using gap detection procedures. There is some research showing that gap detection can be evaluated using an electrophysiological procedure. However, there is currently no research establishing gap detection threshold using the N1-P2 response. The purposes of the current study were to 1) determine gap detection thresholds in younger and older normal-hearing adults using an electrophysiological measure, 2) compare the electrophysiological gap detection threshold and behavioral gap detection threshold within each group, and 3) investigate the effect of age on each gap detection measure. This study utilized an older adult group and younger adult group to compare performance on an electrophysiological and behavioral gap detection procedure. The subjects in this study were 11 younger, normal-hearing adults (mean = 22 yrs) and 11 older, normal-hearing adults (mean = 64.36 yrs). All subjects completed an adaptive behavioral gap detection procedure in order to determine their behavioral gap detection threshold (BGDT). Subjects also completed an electrophysiologic gap detection procedure to determine their electrophysiologic gap detection threshold (EGDT). Older adults demonstrated significantly larger gap detection thresholds than the younger adults. However, EGDT and BGDT were not significantly different in either group. The mean difference between EGDT and BGDT for all subjects was 0.43 msec. Older adults show poorer gap detection ability when compared to younger adults. However, this study shows that gap detection thresholds can be measured using evoked potential recordings and yield results similar to a behavioral measure. American Academy of Audiology.

Evaluation of Treatment Thresholds for Unconjugated Hyperbilirubinemia in Preterm Infants: Effects on Serum Bilirubin and on Hearing Loss?

PubMed Central

Verkerk, Paul H.; Dijk, Peter H.; Van Straaten, Henrica L. M.

2013-01-01

Background Severe unconjugated hyperbilirubinemia may cause deafness. In the Netherlands, 25% lower total serum bilirubin (TSB) treatment thresholds were recently implemented for preterm infants. Objective To determine the rate of hearing loss in jaundiced preterms treated at high or at low TSB thresholds. Design/Methods In this retrospective study conducted at two neonatal intensive care units in the Netherlands, we included preterms (gestational age <32 weeks) treated for unconjugated hyperbilirubinemia at high or low TSB thresholds. Infants with major congenital malformations, syndromes, chromosomal abnormalities or toxoplasmosis, rubella, cytomegalovirus, herpes, syphilis, and human immunodeficiency infections were excluded. We analyzed clinical characteristics and TSB levels during the first ten postnatal days. After two failed automated Auditory Brainstem Response (ABR) tests we used the results of the diagnostic ABR examination to define normal, unilateral, and bilateral hearing loss (>35 dB). Results There were 479 patients in the high and 144 in the low threshold group. Both groups had similar gestational ages (29.5 weeks) and birth weights (1300 g). Mean and mean peak TSB levels were significantly lower after the implementation of the novel thresholds: 152±43 µmol/L and 212±52 µmol/L versus 131±37 µmol/L and 188±46 µmol/L for the high versus low thresholds, respectively (P<0.001). The incidence of hearing loss was 2.7% (13/479) in the high and 0.7% (1/144) in the low TSB threshold group (NNT = 50, 95% CI, 25–3302). Conclusions Implementation of lower treatment thresholds resulted in reduced mean and peak TSB levels. The incidence of hearing impairment in preterms with a gestational age <32 weeks treated at low TSB thresholds was substantially lower compared to preterms treated at high TSB thresholds. Further research with larger sample sizes and power is needed to determine if this effect is statistically significant. PMID:23667532

Evaluation of treatment thresholds for unconjugated hyperbilirubinemia in preterm infants: effects on serum bilirubin and on hearing loss?

PubMed

Hulzebos, Christian V; van Dommelen, Paula; Verkerk, Paul H; Dijk, Peter H; Van Straaten, Henrica L M

2013-01-01

Severe unconjugated hyperbilirubinemia may cause deafness. In the Netherlands, 25% lower total serum bilirubin (TSB) treatment thresholds were recently implemented for preterm infants. To determine the rate of hearing loss in jaundiced preterms treated at high or at low TSB thresholds. In this retrospective study conducted at two neonatal intensive care units in the Netherlands, we included preterms (gestational age <32 weeks) treated for unconjugated hyperbilirubinemia at high or low TSB thresholds. Infants with major congenital malformations, syndromes, chromosomal abnormalities or toxoplasmosis, rubella, cytomegalovirus, herpes, syphilis, and human immunodeficiency infections were excluded. We analyzed clinical characteristics and TSB levels during the first ten postnatal days. After two failed automated Auditory Brainstem Response (ABR) tests we used the results of the diagnostic ABR examination to define normal, unilateral, and bilateral hearing loss (>35 dB). There were 479 patients in the high and 144 in the low threshold group. Both groups had similar gestational ages (29.5 weeks) and birth weights (1300 g). Mean and mean peak TSB levels were significantly lower after the implementation of the novel thresholds: 152 ± 43 µmol/L and 212 ± 52 µmol/L versus 131 ± 37 µmol/L and 188 ± 46 µmol/L for the high versus low thresholds, respectively (P<0.001). The incidence of hearing loss was 2.7% (13/479) in the high and 0.7% (1/144) in the low TSB threshold group (NNT = 50, 95% CI, 25-3302). Implementation of lower treatment thresholds resulted in reduced mean and peak TSB levels. The incidence of hearing impairment in preterms with a gestational age <32 weeks treated at low TSB thresholds was substantially lower compared to preterms treated at high TSB thresholds. Further research with larger sample sizes and power is needed to determine if this effect is statistically significant.

In what root-zone N concentration does nitrate start to leach significantly? A reasonable answer from modeling Mediterranean field data and closed root-zone experiments

NASA Astrophysics Data System (ADS)

Kurtzman, D.; Kanner, B.; Levy, Y.; Shapira, R. H.; Bar-Tal, A.

2017-12-01

Closed-root-zone experiments (e.g. pots, lyzimeters) reveal in many cases a mineral-nitrogen (N) concentration from which the root-N-uptake efficiency reduces significantly and nitrate leaching below the root-zone increases dramatically. A les-direct way to reveal this threshold concentration in agricultural fields is to calibrate N-transport models of the unsaturated zone to nitrate data of the deep samples (under the root-zone) by fitting the threshold concentration of the nitrate-uptake function. Independent research efforts of these two types in light soils where nitrate problems in underlying aquifers are common reviled: 1) that the threshold exists for most crops (filed, vegetables and orchards); 2) nice agreement on the threshold value between the two very different research methodologies; and 3) the threshold lies within 20-50 mg-N/L. Focusing on being below the threshold is a relatively simple aim in the way to maintain intensive agriculture with limited effects on the nitrate concentration in the underlying water resource. Our experience show that in some crops this threshold coincides with the end-of-rise of the N-yield curve (e.g. corn); in this case, it is relatively easy to convince farmers to fertilize below threshold. In other crops, although significant N is lost to leaching the crop can still use higher N concentration to increase yield (e.g. potato).

The regional effect of spinal manipulation on the pressure pain threshold in asymptomatic subjects: a systematic literature review.

PubMed

Honoré, Margaux; Leboeuf-Yde, Charlotte; Gagey, Olivier

2018-01-01

Spinal manipulation (SM) has been shown to have an effect on pain perception. More knowledge is needed on this phenomenon and it would be relevant to study its effect in asymptomatic subjects. To compare regional effect of SM on pressure pain threshold (PPT) vs. sham, inactive control, mobilisation, another SM, and some type of physical therapy. In addition, we reported the results for the three different spinal regions. A systematic search of literature was done using PubMed, Embase and Cochrane. Search terms were ((spinal manipulation) AND (experimental pain)); ((spinal manipulative therapy OR spinal manipulation) AND ((experimental pain OR quantitative sensory testing OR pressure pain threshold OR pain threshold)) (Final search: June 13th 2017). The inclusion criteria were SM performed anywhere in the spine; the use of PPT, PPT tested in an asymptomatic region and on the same day as the SM. Studies had to be experimental with at least one external or internal control group. Studies on only spinal motion or tenderness, other reviews, case reports, and less than 15 invited participants in each group were excluded. Evidence tables were constructed with information relevant to each research question and by spinal region. Results were reported in relation to statistical significance and were interpreted taking into account their quality. Only 12 articles of 946 were accepted. The quality of studies was generally good. In 8 sham controlled studies, a psychologically and physiologically "credible" sham was found in only 2 studies. A significant difference was noted between SM vs. Sham, and between SM and an inactive control. No significant difference in PPT was found between SM and another SM, mobilisation or some type of physical therapy. The cervical region more often obtained significant findings as compared to studies in the thoracic or lumbar regions. SM has an effect regionally on pressure pain threshold in asymptomatic subjects. The clinical significance of this must be quantified. More knowledge is needed in relation to the comparison of different spinal regions and different types of interventions.

Auditory Brainstem Response Thresholds to Air- and Bone-Conducted CE-Chirps in Neonates and Adults.

PubMed

Cobb, Kensi M; Stuart, Andrew

2016-08-01

The purpose of this study was to compare auditory brainstem response (ABR) thresholds to air- and bone-conducted CE-Chirps in neonates and adults. Thirty-two neonates with no physical or neurologic challenges and 20 adults with normal hearing participated. ABRs were acquired with a starting intensity of 30 dB normal hearing level (nHL). The lowest stimulus intensity level at which a wave V was identifiable and replicable was considered the ABR threshold. ABR thresholds to air-conducted CE-Chirps were 9.8 dB nHL for neonates and adults. ABR thresholds to bone-conducted CE-Chirps were 3.8 and 13.8 dB nHL for neonates and adults, respectively. The difference in ABR thresholds to bone-conducted CE-Chirps was significantly different (p < .0001, ηp2 = .45). Adults had significantly larger wave V amplitudes to air- (p < .0001, ηp2 = .50) and bone-conducted (p = .013, ηp2 = .15) CE-Chirps at a stimulus intensity of 30 dB nHL. At the same intensity, adults evidenced significantly shorter wave V latencies (p < .0001, ηp2 = .49) only with air-conducted CE-chirps. The difference in ABR thresholds and wave V latencies to air- and bone-conducted CE-Chirps between neonates and adults may be attributed to a disparity in effective signal delivery to the cochlea.

The influence of weight loss on anaerobic threshold in obese women.

PubMed

Zak-Golab, Agnieszka; Zahorska-Markiewicz, Barbara; Langfort, Józef; Kocelak, Piotr; Holecki, Michal; Mizia-Stec, Katarzyna; Olszanecka-Glinianowicz, Magdalena; Chudek, Jerzy

2010-01-01

Obesity is associated with decreased physical activity. The aim of the study was to assess the anaerobic threshold in obese and normal weight women and to analyse the effect of weight-reduction therapy on the determined thresholds. 42 obese women without concomitant disease (age 30.5 ± 6.9y; BMI 33.6 ± 3.7 kg·m(-2)) and 19 healthy normal weight women (age 27.6 ± 7.0y; BMI 21.2 ± 1.9 kg·m(-2)) performed cycle ergometer incremental ramp exercise test up to exhaustion. The test was repeated in 19 obese women after 12.3 ± 4.2% weight loss. The lactate threshold (LT) and the ventilatory threshold (VT) were determined. Obese women had higher lactate (expressed as oxygen consumption) and ventilator threshold than normal weight women. The lactate threshold was higher than ventilatory one both in obese and normal weight women (1.11 ± 0.21 vs 0.88 ± 0.18 L·min(-1), p < 0.001; 0.94 ± 0.15 vs 0.79 ± 0.23 L·min(- 1), p < 0.01, respectively). After weight reduction therapy neither the lactate nor the ventilatory threshold changed significantly. The results concluded that; 1. The higher lactate threshold noted in obese women may be related to the increased fat acid usage in metabolism. 2. Both in obese and normal weight women lactate threshold appears at higher oxygen consumption than ventilatory threshold. 3. The obtained weight reduction, without weight normalisation was insufficient to cause significant changes of lactate and ventilatory thresholds in obese women. Key pointsResults showed that adolescent young female gymnasts have an altered serum inflammatory markers and endothelial activation, compared to their less physically active peers.Physical activities improved immune system.Differences in these biochemical data kept significant after adjustment for body weight and height.

Effect of a single dose of dextromethorphan on psychomotor performance and working memory capacity.

PubMed

Al-Kuraishy, Hayder M; Al-Gareeb, Ali I; Ashor, Ammar Waham

2012-04-01

Previous studies show that the prolonged use of dextromethorphan produces cognitive deterioration in humans. The aim of this study was to investigate the effect of a single dose of dextroemthrophan on psychomotor performance and working memory capacity. This is a randomized, double-blind, controlled, and prospective study. Thirty-six (17 women, 19 men) medical students enrolled in the study; half of them (7 women, 11 men) were given placebo, while the other half (10 women, 8 men) received dextromethorphan. The choice reaction time, critical flicker fusion threshold, and N-back working memory task were measured before and after 2 h of taking the drugs. Dextromethorphan showed a significant deterioration in the 3-back working memory task (P<0.05). No significant changes were seen as regards the choice reaction time components (total, recognition, motor) and critical flicker fusion threshold (P>0.05). On the other hand, placebo showed no significant changes as regards the choice reaction time, critical flicker fusion threshold, and N-back working memory task (P>0.05). A single dose of dextromethorphan has no effect on attention and arousal but may significantly impair the working memory capacity.

Noise-Driven Manifestation of Learning in Mature Neural Networks

NASA Astrophysics Data System (ADS)

Monterola, Christopher; Saloma, Caesar

2002-10-01

We show that the generalization capability of a mature thresholding neural network to process above-threshold disturbances in a noise-free environment is extended to subthreshold disturbances by ambient noise without retraining. The ability to benefit from noise is intrinsic and does not have to be learned separately. Nonlinear dependence of sensitivity with noise strength is significantly narrower than in individual threshold systems. Noise has a minimal effect on network performance for above-threshold signals. We resolve two seemingly contradictory responses of trained networks to noise-their ability to benefit from its presence and their robustness against noisy strong disturbances.

Hypoalgesia in response to transcutaneous electrical nerve stimulation (TENS) depends on stimulation intensity.

PubMed

Moran, Fidelma; Leonard, Tracey; Hawthorne, Stephanie; Hughes, Ciara M; McCrum-Gardner, Evie; Johnson, Mark I; Rakel, Barbara A; Sluka, Kathleen A; Walsh, Deirdre M

2011-08-01

Transcutaneous electrical nerve stimulation (TENS) is an electrophysical modality used for pain management. This study investigated the dose response of different TENS intensities on experimentally induced pressure pain. One hundred and thirty TENS naïve healthy individuals (18-64 years old; 65 males, 65 females) were randomly allocated to 5 groups (n = 26 per group): Strong Non Painful TENS; Sensory Threshold TENS; Below Sensory Threshold TENS; No Current Placebo TENS; and Transient Placebo TENS. Active TENS (80 Hz) was applied to the forearm for 30 minutes. Transient Placebo TENS was applied for 42 seconds after which the current amplitude automatically reset to 0 mA. Pressure pain thresholds (PPT) were recorded from 2 points on the hand and forearm before and after TENS to measure hypoalgesia. There were significant differences between groups at both the hand and forearm (ANOVA; P = .005 and .002). At 30 minutes, there was a significant hypoalgesic effect in the Strong Non Painful TENS group compared to: Below Sensory Threshold TENS, No Current Placebo TENS and Transient Placebo TENS groups (P < .0001) at the forearm; Transient Placebo TENS and No Current Placebo TENS groups at the hand (P = .001). There was no significant difference between Strong Non Painful TENS and Sensory Threshold TENS groups. The area under the curve for the changes in PPT significantly correlated with the current amplitude (r(2) = .33, P = .003). These data therefore show that there is a dose-response effect of TENS with the largest effect occurring with the highest current amplitudes. This study shows a dose response for the intensity of TENS for pain relief with the strongest intensities showing the greatest effect; thus, we suggest that TENS intensity should be titrated to achieve the strongest possible intensity to achieve maximum pain relief. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

The immediate effects of lidocaine iontophoresis using interferential current on pressure sense threshold and tactile sensation.

PubMed

Yoosefinejad, Amin Kordi; Motealleh, Alireza; Abbasnia, Keramatollah

2016-01-01

Iontophoresis is the noninvasive delivery of ions using direct current. The direct current has some disadvantages such as skin burning. Interferential current is a kind of alternating current without limitations of direct current; so the purpose of this study is to investigate and compare the effects of lidocaine, interferential current and lidocaine iontophoresis using interferential current. 30 healthy women aged 20-24 years participated in this randomized clinical trial study. Pressure, tactile and pain thresholds were evaluated before and after the application of treatment methods. Pressure, tactile and pain sensitivity increased significantly after the application of lidocaine alone (p < 0.005) and lidocaine iontophoresis using interferential current (p < 0.0001). Lidocaine iontophoresis using interferential current can increase perception threshold of pain, tactile stimulus and pressure sense more significantly than lidocaine and interferential current alone.

Prefrontal rTMS for treating depression: location and intensity results from the OPT-TMS multi-site clinical trial.

PubMed

Johnson, Kevin A; Baig, Mirza; Ramsey, Dave; Lisanby, Sarah H; Avery, David; McDonald, William M; Li, Xingbao; Bernhardt, Elisabeth R; Haynor, David R; Holtzheimer, Paul E; Sackeim, Harold A; George, Mark S; Nahas, Ziad

2013-03-01

Motor cortex localization and motor threshold determination often guide Transcranial Magnetic Stimulation (TMS) placement and intensity settings for non-motor brain stimulation. However, anatomic variability results in variability of placement and effective intensity. Post-study analysis of the OPT-TMS Study reviewed both the final positioning and the effective intensity of stimulation (accounting for relative prefrontal scalp-cortex distances). We acquired MRI scans of 185 patients in a multi-site trial of left prefrontal TMS for depression. Scans had marked motor sites (localized with TMS) and marked prefrontal sites (5 cm anterior of motor cortex by the "5 cm rule"). Based on a visual determination made before the first treatment, TMS therapy occurred either at the 5 cm location or was adjusted 1 cm forward. Stimulation intensity was 120% of resting motor threshold. The "5 cm rule" would have placed stimulation in premotor cortex for 9% of patients, which was reduced to 4% with adjustments. We did not find a statistically significant effect of positioning on remission, but no patients with premotor stimulation achieved remission (0/7). Effective stimulation ranged from 93 to 156% of motor threshold, and no seizures were induced across this range. Patients experienced remission with effective stimulation intensity ranging from 93 to 146% of motor threshold, and we did not find a significant effect of effective intensity on remission. Our data indicates that individualized positioning methods are useful to reduce variability in placement. Stimulation at 120% of motor threshold, unadjusted for scalp-cortex distances, appears safe for a broad range of patients. Copyright © 2013 Elsevier Inc. All rights reserved.

Protective effects of brain-derived neurotrophic factor on the noise-damaged cochlear spiral ganglion.

PubMed

Zhai, S-Q; Guo, W; Hu, Y-Y; Yu, N; Chen, Q; Wang, J-Z; Fan, M; Yang, W-Y

2011-05-01

To explore the protective effects of brain-derived neurotrophic factor on the noise-damaged cochlear spiral ganglion. Recombinant adenovirus brain-derived neurotrophic factor vector, recombinant adenovirus LacZ and artificial perilymph were prepared. Guinea pigs with audiometric auditory brainstem response thresholds of more than 75 dB SPL, measured seven days after four hours of noise exposure at 135 dB SPL, were divided into three groups. Adenovirus brain-derived neurotrophic factor vector, adenovirus LacZ and perilymph were infused into the cochleae of the three groups, variously. Eight weeks later, the cochleae were stained immunohistochemically and the spiral ganglion cells counted. The auditory brainstem response threshold recorded before and seven days after noise exposure did not differ significantly between the three groups. However, eight weeks after cochlear perfusion, the group receiving brain-derived neurotrophic factor had a significantly decreased auditory brainstem response threshold and increased spiral ganglion cell count, compared with the adenovirus LacZ and perilymph groups. When administered via cochlear infusion following noise damage, brain-derived neurotrophic factor appears to improve the auditory threshold, and to have a protective effect on the spiral ganglion cells.

Vestibular evoked myogenic potential (VEMP) testing: normative threshold response curves and effects of age.

PubMed

Janky, Kristen L; Shepard, Neil

2009-09-01

Vestibular evoked myogenic potential (VEMP) testing has gained increased interest in the diagnosis of a variety of vestibular etiologies. P13/N23 latency, amplitude and threshold response curves have been used to compare pathologic groups to normal controls. Appropriate characterization of these etiologies requires normative data across the frequency spectrum and age range. The objective of the current study was to test the hypothesis that significant changes in VEMP responses occur as a function of increased age across all test stimuli as well as characterize the VEMP threshold response curve across age. This project incorporated a prospective study design using a sample of convenience. Openly recruited subjects were assigned to groups according to age. Forty-six normal controls ranging between 20 and 76 years of age participated in the study. Participants were separated by decade into five age categories from 20 to 60 plus years. Normal participants were characterized by having normal hearing sensitivity, no history of neurologic or balance/dizziness involvement, and negative results on a direct office vestibular examination. VEMP responses were measured at threshold to click and 250, 500, 750, and 1000 Hz tone burst stimuli and at a suprathreshold level to 500 Hz toneburst stimuli at123 dB SPL. A mixed group factorial ANOVA (analysis of variance) and linear regression were performed to examine the effects of VEMP characteristics on age. There were no significant differences between ears for any of the test parameters. There were no significant differences between age groups for n23 latency or amplitude in response to any of the stimuli. Significant mean differences did exist between age groups for p13 latency (250, 750, and 1000 Hz) and threshold (500 and 750 Hz). Age was significantly correlated with VEMP parameters. VEMP threshold was positively correlated (250, 500, 750, 1000 Hz); and amplitude was negatively correlated (500 Hz maximum). The threshold response curves revealed best frequency tuning at 500 Hz with the highest thresholds in response to click stimuli. However, this best frequency tuning dissipated with increased age. VEMP response rates also decreased with increased age. We have demonstrated that minor differences in VEMP responses occur with age. Given the reduced response rates and flattened frequency tuning curve for individuals over the age of 60, frequency tuning curves may not be a good diagnostic indicator for this age group.

The effects of ambient temperature on cerebrovascular mortality: an epidemiologic study in four climatic zones in China

PubMed Central

2014-01-01

Background Little evidence is available about the association between temperature and cerebrovascular mortality in China. This study aims to examine the effects of ambient temperature on cerebrovascular mortality in different climatic zones in China. Method We obtained daily data on weather conditions, air pollution and cerebrovascular deaths from five cities (Beijing, Tianjin, Shanghai, Wuhan, and Guangzhou) in China during 2004-2008. We examined city-specific associations between ambient temperature and the cerebrovascular mortality, while adjusting for season, long-term trends, day of the week, relative humidity and air pollution. We examined cold effects using a 1°C decrease in temperature below a city-specific threshold, and hot effects using a 1°C increase in temperature above a city-specific threshold. We used a meta-analysis to summarize the cold and hot effects across the five cities. Results Beijing and Tianjin (with low mean temperature) had lower thresholds than Shanghai, Wuhan and Guangzhou (with high mean temperature). In Beijing, Tianjin, Wuhan and Guangzhou cold effects were delayed, while in Shanghai there was no or short induction. Hot effects were acute in all five cities. The cold effects lasted longer than hot effects. The hot effects were followed by mortality displacement. The pooled relative risk associated with a 1°C decrease in temperature below thresholds (cold effect) was 1.037 (95% confidence interval (CI): 1.020, 1.053). The pooled relative risk associated with a 1°C increase in temperature above thresholds (hot effect) was 1.014 (95% CI: 0.979, 1.050). Conclusion Cold temperatures are significantly associated with cerebrovascular mortality in China, while hot effect is not significant. People in colder climate cities were sensitive to hot temperatures, while people in warmer climate cities were vulnerable to cold temperature. PMID:24690204

Multivariate Analyses of Balance Test Performance, Vestibular Thresholds, and Age

PubMed Central

Karmali, Faisal; Bermúdez Rey, María Carolina; Clark, Torin K.; Wang, Wei; Merfeld, Daniel M.

2017-01-01

We previously published vestibular perceptual thresholds and performance in the Modified Romberg Test of Standing Balance in 105 healthy humans ranging from ages 18 to 80 (1). Self-motion thresholds in the dark included roll tilt about an earth-horizontal axis at 0.2 and 1 Hz, yaw rotation about an earth-vertical axis at 1 Hz, y-translation (interaural/lateral) at 1 Hz, and z-translation (vertical) at 1 Hz. In this study, we focus on multiple variable analyses not reported in the earlier study. Specifically, we investigate correlations (1) among the five thresholds measured and (2) between thresholds, age, and the chance of failing condition 4 of the balance test, which increases vestibular reliance by having subjects stand on foam with eyes closed. We found moderate correlations (0.30–0.51) between vestibular thresholds for different motions, both before and after using our published aging regression to remove age effects. We found that lower or higher thresholds across all threshold measures are an individual trait that account for about 60% of the variation in the population. This can be further distributed into two components with about 20% of the variation explained by aging and 40% of variation explained by a single principal component that includes similar contributions from all threshold measures. When only roll tilt 0.2 Hz thresholds and age were analyzed together, we found that the chance of failing condition 4 depends significantly on both (p = 0.006 and p = 0.013, respectively). An analysis incorporating more variables found that the chance of failing condition 4 depended significantly only on roll tilt 0.2 Hz thresholds (p = 0.046) and not age (p = 0.10), sex nor any of the other four threshold measures, suggesting that some of the age effect might be captured by the fact that vestibular thresholds increase with age. For example, at 60 years of age, the chance of failing is roughly 5% for the lowest roll tilt thresholds in our population, but this increases to 80% for the highest roll tilt thresholds. These findings demonstrate the importance of roll tilt vestibular cues for balance, even in individuals reporting no vestibular symptoms and with no evidence of vestibular dysfunction. PMID:29167656

Effect of a lateral glide mobilisation with movement of the hip on vibration threshold in healthy volunteers.

PubMed

Smith, Darren A; Saranga, Jacob; Pritchard, Andrew; Kommatas, Nikolaos A; Punnoose, Shinu Kovelal; Kale, Supriya Tukaram

2018-01-01

Mulligan's mobilisation-with-movement (MWM) techniques are proposed to achieve their clinical benefit via neurophysiological mechanisms. However, previous research has focussed on responses in the sympathetic nervous system only, and is not conclusive. An alternative measure of neurophysiological response to MWM is required to support or refute this mechanism of action. Recently, vibration threshold (VT) has been used to quantify changes in the sensory nervous system in patients experiencing musculoskeletal pain. To investigate the effect of a lateral glide MWM of the hip joint on vibration threshold compared to a placebo and control condition in asymptomatic volunteers. Fifteen asymptomatic volunteers participated in this single-blinded, randomised, within-subject, placebo, control design. Participants received each of three interventions in a randomised order; a lateral glide MWM of the hip joint into flexion, a placebo MWM, and a control intervention. Vibration threshold (VT) measures were taken at baseline and immediately after each intervention. Mean change in VT from baseline was calculated for each intervention and then analysed for between group differences using a one-way analysis of variance (ANOVA). A one-way ANOVA revealed no statistically significant differences between the three experimental conditions (P = 0.812). This small study found that a lateral glide MWM of the hip did not significantly change vibration threshold compared to a placebo and control intervention in an asymptomatic population. This study provides a method of using vibration threshold to investigate the potential neurophysiological effects of a manual therapy intervention that should be repeated in a larger, symptomatic population. Copyright © 2016 Elsevier Ltd. All rights reserved.

The thresholds for statistical and clinical significance – a five-step procedure for evaluation of intervention effects in randomised clinical trials

PubMed Central

2014-01-01

Background Thresholds for statistical significance are insufficiently demonstrated by 95% confidence intervals or P-values when assessing results from randomised clinical trials. First, a P-value only shows the probability of getting a result assuming that the null hypothesis is true and does not reflect the probability of getting a result assuming an alternative hypothesis to the null hypothesis is true. Second, a confidence interval or a P-value showing significance may be caused by multiplicity. Third, statistical significance does not necessarily result in clinical significance. Therefore, assessment of intervention effects in randomised clinical trials deserves more rigour in order to become more valid. Methods Several methodologies for assessing the statistical and clinical significance of intervention effects in randomised clinical trials were considered. Balancing simplicity and comprehensiveness, a simple five-step procedure was developed. Results For a more valid assessment of results from a randomised clinical trial we propose the following five-steps: (1) report the confidence intervals and the exact P-values; (2) report Bayes factor for the primary outcome, being the ratio of the probability that a given trial result is compatible with a ‘null’ effect (corresponding to the P-value) divided by the probability that the trial result is compatible with the intervention effect hypothesised in the sample size calculation; (3) adjust the confidence intervals and the statistical significance threshold if the trial is stopped early or if interim analyses have been conducted; (4) adjust the confidence intervals and the P-values for multiplicity due to number of outcome comparisons; and (5) assess clinical significance of the trial results. Conclusions If the proposed five-step procedure is followed, this may increase the validity of assessments of intervention effects in randomised clinical trials. PMID:24588900

The effect of sertraline and 8-OH-DPAT on the PTZ_induced seizure threshold: Role of the nitrergic system.

PubMed

Heydari, Azhdar; Davoudi, Shima

2017-02-01

Serotonin is a key regulatory neurotransmitter in the CNS which plays an important role in seizure through different receptors, especially the 5HT 1A subtype. The role of sertraline through the 5HT 1A receptor and nitric oxide interaction on the PTZ-induced seizure threshold was investigated in this study. In this study, 70 white male mice were randomly divided into 10 groups including intact control, sham-control and eight experimental groups which received sertraline, 8-OH-DPAT, WAY100635, WAY100635+sertraline, WAY100635+8-OH-DPAT, L-NAME, L-NAME+sertraline and L-NAME+8-OH-DPAT. After 14days of treatment in different groups, the PTZ-induced seizure threshold was assessed and the measurement of nitric oxide metabolites in the brain tissue was done with the Greiss method. The seizure threshold was significantly increased in the sertraline and 8OH-DPAT receiving groups compared to the sham group (P<0.001). In the presence of WAY100635, the effect of both sertraline and 8-OH-DPAT in raising the seizure threshold was more prominent (P<0.001) but on the other hand, in the presence of L-NAME, an increase in the anticonvulsant effect of 8-OH-DPAT was observed, while L-NAME alone had no effect on the seizure threshold (P<0.001). The NO X concentration was significantly decreased in the 8-OH-DPAT_treated group (P<0.01), while the WAY100657 reversed it and the combination of 8-OH-DPAT with L-NAME reduced the NO X levels (P<0.001). These findings support the anticonvulsant effect of SSRIs and selective 5HT 1A receptors, although serotonin receptors other than 5HT 1A subtype may be involved and also it is probable that some anticonvulsant effects of the sertraline and 8-OH-DPAT are through the modulation of nitrergic system. Copyright © 2016 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

Discovery and validation of sub-threshold genome-wide association study loci using epigenomic signatures

PubMed Central

Wang, Xinchen; Tucker, Nathan R; Rizki, Gizem; Mills, Robert; Krijger, Peter HL; de Wit, Elzo; Subramanian, Vidya; Bartell, Eric; Nguyen, Xinh-Xinh; Ye, Jiangchuan; Leyton-Mange, Jordan; Dolmatova, Elena V; van der Harst, Pim; de Laat, Wouter; Ellinor, Patrick T; Newton-Cheh, Christopher; Milan, David J; Kellis, Manolis; Boyer, Laurie A

2016-01-01

Genetic variants identified by genome-wide association studies explain only a modest proportion of heritability, suggesting that meaningful associations lie 'hidden' below current thresholds. Here, we integrate information from association studies with epigenomic maps to demonstrate that enhancers significantly overlap known loci associated with the cardiac QT interval and QRS duration. We apply functional criteria to identify loci associated with QT interval that do not meet genome-wide significance and are missed by existing studies. We demonstrate that these 'sub-threshold' signals represent novel loci, and that epigenomic maps are effective at discriminating true biological signals from noise. We experimentally validate the molecular, gene-regulatory, cellular and organismal phenotypes of these sub-threshold loci, demonstrating that most sub-threshold loci have regulatory consequences and that genetic perturbation of nearby genes causes cardiac phenotypes in mouse. Our work provides a general approach for improving the detection of novel loci associated with complex human traits. DOI: http://dx.doi.org/10.7554/eLife.10557.001 PMID:27162171

Effects of nicotine and minor tobacco alkaloids on intracranial-self-stimulation in rats.

PubMed

Harris, Andrew C; Tally, Laura; Muelken, Peter; Banal, Andrew; Schmidt, Clare E; Cao, Qing; LeSage, Mark G

2015-08-01

While nicotine is the primary addictive compound in tobacco, other tobacco constituents including minor alkaloids (e.g., nornicotine, anabasine) may also contribute to tobacco addiction by mimicking or enhancing the effects of nicotine. Further evaluating the behavioral effects of minor alkaloids is essential for understanding their impact on tobacco addiction and informing development of tobacco product standards by the FDA. This study compared the addiction-related effects of nicotine and the minor alkaloids nornicotine, anabasine, myosmine, anatabine, and cotinine on intracranial self-stimulation (ICSS) thresholds in rats. Acute injection of nicotine produced reinforcement-enhancing (ICSS threshold-decreasing) effects at low to moderate doses, and reinforcement-attenuating/aversive (ICSS threshold-increasing) effects at high doses. Nornicotine and anabasine produced similar biphasic effects on ICSS thresholds, although with lower potency compared to nicotine. Myosmine only elevated ICSS thresholds at relatively high doses, while anatabine and cotinine did not influence ICSS thresholds at any dose. None of the alkaloids significantly influenced ICSS response latencies, indicating a lack of nonspecific motoric effects. These findings indicate that some minor tobacco alkaloids can either fully (nornicotine, anabasine) or partially (myosmine) mimic nicotine's addiction-related effects on ICSS, albeit at reduced potency. These findings emphasize the need for further study of the abuse potential of minor alkaloids, including evaluation of their effects when combined with nicotine and other tobacco constituents to better simulate tobacco exposure in humans. Such work is essential for informing FDA regulation of tobacco products and could also lead to the development of novel pharmacotherapies for tobacco addiction. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Update on the recommended viewing protocol for FAXIL threshold contrast detail detectability test objects used in television fluoroscopy.

PubMed

Launders, J H; McArdle, S; Workman, A; Cowen, A R

1995-01-01

The significance of varying the viewing conditions that may affect the perceived threshold contrast of X-ray television fluoroscopy systems has been investigated. Factors investigated include the ambient room lighting and the viewing distance. The purpose of this study is to find the optimum viewing protocol with which to measure the threshold detection index. This is a particular problem when trying to compare the image quality of television fluoroscopy systems in different input field sizes. The results show that the viewing distance makes a significant difference to the perceived threshold contrast, whereas the ambient light conditions make no significant difference. Experienced observers were found to be capable of finding the optimum viewing distance for detecting details of each size, in effect using a flexible viewing distance. This allows the results from different field sizes to be normalized to account for both the magnification and the entrance air kerma rate differences, which in turn allow for a direct comparison of performance in different field sizes.

The effect of condoms on penile vibrotactile sensitivity thresholds in young, heterosexual men

PubMed Central

Hill, Brandon J.; Janssen, Erick; Kvam, Peter; Amick, Erick E.; Sanders, Stephanie A.

2013-01-01

Introduction Investigating the ways in which barrier methods such as condoms may affect penile sensory thresholds has potential relevance to the development of interventions in men who experience negative effects of condoms on sexual response and sensation. A quantitative, psychophysiological investigation examining the degree to which sensations are altered by condoms has, to date, not been conducted. Aim The objective of this study was to examine penile vibrotactile sensitivity thresholds in both flaccid and erect penises with and without a condom, while comparing men who do and those who do not report condom-associated erection problems (CAEP). Methods Penile vibrotactile sensitivity thresholds were assessed among a total of 141 young, heterosexual men using biothesiometry. An incremental two-step staircase method was used and repeated three times for each of four conditions. Intra-class correlation coefficients (ICC) were calculated for all vibratory assessments. Penile vibratory thresholds were compared using a mixed-model Analysis of Variance (ANOVA). Main Outcome Measures Penile vibrotactile sensitivity thresholds with and without a condom, erectile function measured by International Index of Erectile Function Questionnaire (IIEF), and self-reported degree of erection. Results Significant main effects of condoms (yes/no) and erection (yes/no) were found. No main or interaction effects of CAEP were found. Condoms were associated with higher penile vibrotactile sensitivity thresholds (F(1, 124)=17.11, p<.001). Penile vibrotactile thresholds were higher with an erect than with a flaccid penis (F(1, 124)=4.21, p=.042). Conclusion The current study demonstrates the feasibility of measuring penile vibratory thresholds with and without a condom in both erect and flaccid experimental conditions. As might be expected, condoms increased penile vibrotactile sensitivity thresholds. Interestingly, erections were associated with the highest thresholds. Thus, this study was the first to document that erect penises are less sensitive to vibrotactile stimulation than flaccid penises. PMID:24168347

Formant discrimination in noise for isolated vowels

NASA Astrophysics Data System (ADS)

Liu, Chang; Kewley-Port, Diane

2004-11-01

Formant discrimination for isolated vowels presented in noise was investigated for normal-hearing listeners. Discrimination thresholds for F1 and F2, for the seven American English vowels /eye, smcapi, eh, æ, invv, aye, you/, were measured under two types of noise, long-term speech-shaped noise (LTSS) and multitalker babble, and also under quiet listening conditions. Signal-to-noise ratios (SNR) varied from -4 to +4 dB in steps of 2 dB. All three factors, formant frequency, signal-to-noise ratio, and noise type, had significant effects on vowel formant discrimination. Significant interactions among the three factors showed that threshold-frequency functions depended on SNR and noise type. The thresholds at the lowest levels of SNR were highly elevated by a factor of about 3 compared to those in quiet. The masking functions (threshold vs SNR) were well described by a negative exponential over F1 and F2 for both LTSS and babble noise. Speech-shaped noise was a slightly more effective masker than multitalker babble, presumably reflecting small benefits (1.5 dB) due to the temporal variation of the babble. .

Is the diagnostic threshold for bulimia nervosa clinically meaningful?

PubMed

Chapa, Danielle A N; Bohrer, Brittany K; Forbush, Kelsie T

2018-01-01

The DSM-5 differentiates full- and sub-threshold bulimia nervosa (BN) according to average weekly frequencies of binge eating and inappropriate compensatory behaviors. This study was the first to evaluate the modified frequency criterion for BN published in the DSM-5. The purpose of this study was to test whether community-recruited adults (N=125; 83.2% women) with current full-threshold (n=77) or sub-threshold BN (n=48) differed in comorbid psychopathology and eating disorder (ED) illness duration, symptom severity, and clinical impairment. Participants completed the Clinical Impairment Assessment and participated in semi-structured clinical interviews of ED- and non-ED psychopathology. Differences between the sub- and full-threshold BN groups were assessed using MANOVA and Chi-square analyses. ED illness duration, age-of-onset, body mass index (BMI), alcohol and drug misuse, and the presence of current and lifetime mood or anxiety disorders did not differ between participants with sub- and full-threshold BN. Participants with full-threshold BN had higher levels of clinical impairment and weight concern than those with sub-threshold BN. However, minimal clinically important difference analyses suggested that statistically significant differences between participants with sub- and full-threshold BN on clinical impairment and weight concern were not clinically significant. In conclusion, sub-threshold BN did not differ from full-threshold BN in clinically meaningful ways. Future studies are needed to identify an improved frequency criterion for BN that better distinguishes individuals in ways that will more validly inform prognosis and effective treatment planning for BN. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of urbanization on the chemical, physical, and biological characteristics of small blackland prairie dtreams in and near the Dallas-Fort Worth Metropolitan Area, Texas: Chapter C in Effects of urbanization on stream ecosystems in six metropolitan areas of the United States

USGS Publications Warehouse

Moring, J. Bruce

2009-01-01

In 2001, the U.S. Geological Survey National Water Quality Assessment Program began a series of studies in the contiguous United States to examine the effects of urbanization on the chemical, physical, and biological characteristics of streams. Small streams in the Texas Blackland Prairie level III ecoregion in and near the Dallas-Fort Worth metropolitan area were the focus of one of the studies. The principal objectives of the study, based on data collected in 2003-04 from 28 subbasins of the Trinity River Basin, were to (1) define a gradient of urbanization for small Blackland Prairie streams in the Trinity River Basin on the basis of a range of urban intensity indexes (UIIs) calculated using land-use/land-cover, infrastructure, and socioeconomic characteristics; (2) assess the relation between this gradient of urbanization and the chemical, physical, and biological characteristics of these streams; and (3) evaluate the type of relation (that is, linear or nonlinear, and whether there was a threshold response) of the chemical, physical, and biological characteristics of these streams to the gradient of urbanization. Of 94 water-chemistry variables and one measure of potential toxicity from a bioassay, the concentrations of two pesticides (diazinon and sima-zine) and one measure of potential toxicity (P450RGS assay) from compounds sequestered in semipermeable membrane devices were significantly positively correlated with the UII. No threshold responses to the UII for diazinon and simazine concentrations were observed over the entire range of the UII scores. The linear correlation for diazinon with the UII was significant, but the linear correlation for simazine with the UII was not. No statistically significant relations between the UII and concentrations of suspended sediment, total nitrogen, total phosphorous, or any major ions were indicated. Eleven of 59 physical variables from streamflow were significantly correlated with the UII. Temperature was not significantly correlated with the UII, and none of the physical habitat measurements were significantly correlated with the UII. Seven physical variables categorized as streamflow flashiness metrics were significantly positively correlated with the UII, two of which showed a linear but not a threshold response to the UII. Four flow-duration metrics were significantly negatively correlated with the UII, of which two showed a linear response to the UII, one showed a threshold response, and one showed neither. None of the fish metrics were significantly correlated with the UII in the Blackland Prairie streams. Two qualitative multi-habitat benthic macroinvertebrate metrics, predator richness and percentage filterer-collector richness, were significantly correlated with the UII; predator richness was negatively correlated with the UII, and percentage filterer-collector richness was positively correlated with the UII. No threshold response to the UII was observed for either metric, but both showed a significant linear response to the UII. Three richest targeted habitat (RTH) benthic macroinvertebrate metrics, Margalef's richness, predator richness, and omnivore richness were significantly negatively correlated with the UII. Margalef's richness was the only RTH metric that indicated a threshold response to the UII. The majority of unique taxa collected in the periphytic algae samples were diatoms. Six RTH periphytic algae metrics were correlated with the UII and five of the six showed no notable threshold response to the UII; but all five showed significant linear responses to the UII. Only the metric OT_VL_DP, which indicates the presence of algae that are tolerant of low dissolved oxygen conditions, showed a threshold response to the UII. Six depositional target habitat periphytic algae metrics were correlated with the UII, five of which showed no threshold response to the UII; three of the five showed significant linear responses to the UII, one showed a borderline significant

Cross-modal cueing effects of visuospatial attention on conscious somatosensory perception.

PubMed

Doruk, Deniz; Chanes, Lorena; Malavera, Alejandra; Merabet, Lotfi B; Valero-Cabré, Antoni; Fregni, Felipe

2018-04-01

The impact of visuospatial attention on perception with supraliminal stimuli and stimuli at the threshold of conscious perception has been previously investigated. In this study, we assess the cross-modal effects of visuospatial attention on conscious perception for near-threshold somatosensory stimuli applied to the face. Fifteen healthy participants completed two sessions of a near-threshold cross-modality cue-target discrimination/conscious detection paradigm. Each trial began with an endogenous visuospatial cue that predicted the location of a weak near-threshold electrical pulse delivered to the right or left cheek with high probability (∼75%). Participants then completed two tasks: first, a forced-choice somatosensory discrimination task (felt once or twice?) and then, a somatosensory conscious detection task (did you feel the stimulus and, if yes, where (left/right)?). Somatosensory discrimination was evaluated with the response reaction times of correctly detected targets, whereas the somatosensory conscious detection was quantified using perceptual sensitivity (d') and response bias (beta). A 2 × 2 repeated measures ANOVA was used for statistical analysis. In the somatosensory discrimination task (1 st task), participants were significantly faster in responding to correctly detected targets (p < 0.001). In the somatosensory conscious detection task (2 nd task), a significant effect of visuospatial attention on response bias (p = 0.008) was observed, suggesting that participants had a less strict criterion for stimuli preceded by spatially valid than invalid visuospatial cues. We showed that spatial attention has the potential to modulate the discrimination and the conscious detection of near-threshold somatosensory stimuli as measured, respectively, by a reduction of reaction times and a shift in response bias toward less conservative responses when the cue predicted stimulus location. A shift in response bias indicates possible effects of spatial attention on internal decision processes. The lack of significant results in perceptual sensitivity (d') could be due to weaker effects of endogenous attention on perception.

Acoustic cavitation studies

NASA Astrophysics Data System (ADS)

Crum, L. A.

1981-09-01

The primary thrust of this study was toward a more complete understanding of general aspects of acoustic cavitation. The effect of long-chain polymer additives on the cavitation threshold was investigated to determine if they reduced the acoustic cavitation threshold in a similar manner to the observed reduction in the cavitation index in hydrodynamic cavitation. Measurements were made of the acoustic cavitation threshold as a function of polymer concentration for additives such as guar gum and polyethelene oxide. The measurements were also made as a function of dissolved gas concentration, surface tension and viscosity. It was determined that there was a significant increase in the acoustic cavitation threshold for increased concentrations of the polymer additives (measurable effects could be obtained for concentrations as low as a few parts per million). One would normally expect that an additive that reduces surface tension to decrease the pressure required to cause a cavity to grow and thus these additives, at first thought, should reduce the threshold. However, even in the hydrodynamic case, the threshold was increased. In both of the hydrodynamic cases considered, the explanation for the increased threshold was given in terms of changed fluid dynamics rather than changed physical properties of the fluid.

The effect of olfactory training on the odor threshold in patients with traumatic anosmia.

PubMed

Jiang, Rong-San; Twu, Chih-Wen; Liang, Kai-Li

2017-09-01

Olfactory training is a novel intervention that has been used to treat olfactory dysfunction. This study attempted to investigate the effect of olfactory training in patients with traumatic anosmia. Patients with a clear history of anosmia after experiencing a head injury and whose phenyl ethyl alcohol (PEA) odor detection thresholds were -1 after steroid and zinc treatment were included. The patients were randomly divided into two groups, with patients in one group given a bottle of PEA and those in another group given a bottle of mineral oil for 3-month olfactory training. All the patients were followed up with a PEA threshold test and the traditional Chinese version of the University of Pennsylvania Smell Identification Test (UPSIT-TC). Magnetic resonance imaging was performed to measure the volume of the olfactory bulbs. Any patient whose PEA threshold result was below -1.01 or whose UPSIT-TC score increased four or more points was considered to have shown improvement in their olfactory function. Forty-two patients received PEA olfactory training, whereas 39 received olfactory training with mineral oil. The improvement of PEA thresholds function was observed in 10 patients within the PEA group and in 2 patients in the mineral oil group. The frequency of improvement of threshold within the PEA group was significantly higher than that of the mineral oil group. Neither olfactory bulb volume nor UPSIT-TC score was significantly different between the two groups. Our results showed that olfactory training with PEA can improve PEA odor threshold levels in patients with traumatic anosmia.

Influence of drug load on dissolution behavior of tablets containing a poorly water-soluble drug: estimation of the percolation threshold.

PubMed

Wenzel, Tim; Stillhart, Cordula; Kleinebudde, Peter; Szepes, Anikó

2017-08-01

Drug load plays an important role in the development of solid dosage forms, since it can significantly influence both processability and final product properties. The percolation threshold of the active pharmaceutical ingredient (API) corresponds to a critical concentration, above which an abrupt change in drug product characteristics can occur. The objective of this study was to identify the percolation threshold of a poorly water-soluble drug with regard to the dissolution behavior from immediate release tablets. The influence of the API particle size on the percolation threshold was also studied. Formulations with increasing drug loads were manufactured via roll compaction using constant process parameters and subsequent tableting. Drug dissolution was investigated in biorelevant medium. The percolation threshold was estimated via a model dependent and a model independent method based on the dissolution data. The intragranular concentration of mefenamic acid had a significant effect on granules and tablet characteristics, such as particle size distribution, compactibility and tablet disintegration. Increasing the intragranular drug concentration of the tablets resulted in lower dissolution rates. A percolation threshold of approximately 20% v/v could be determined for both particle sizes of the API above which an abrupt decrease of the dissolution rate occurred. However, the increasing drug load had a more pronounced effect on dissolution rate of tablets containing the micronized API, which can be attributed to the high agglomeration tendency of micronized substances during manufacturing steps, such as roll compaction and tableting. Both methods that were applied for the estimation of percolation threshold provided comparable values.

Noise adaptive wavelet thresholding for speckle noise removal in optical coherence tomography.

PubMed

Zaki, Farzana; Wang, Yahui; Su, Hao; Yuan, Xin; Liu, Xuan

2017-05-01

Optical coherence tomography (OCT) is based on coherence detection of interferometric signals and hence inevitably suffers from speckle noise. To remove speckle noise in OCT images, wavelet domain thresholding has demonstrated significant advantages in suppressing noise magnitude while preserving image sharpness. However, speckle noise in OCT images has different characteristics in different spatial scales, which has not been considered in previous applications of wavelet domain thresholding. In this study, we demonstrate a noise adaptive wavelet thresholding (NAWT) algorithm that exploits the difference of noise characteristics in different wavelet sub-bands. The algorithm is simple, fast, effective and is closely related to the physical origin of speckle noise in OCT image. Our results demonstrate that NAWT outperforms conventional wavelet thresholding.

Effect of Mild Cognitive Impairment and Alzheimer Disease on Auditory Steady-State Responses

PubMed Central

Shahmiri, Elaheh; Jafari, Zahra; Noroozian, Maryam; Zendehbad, Azadeh; Haddadzadeh Niri, Hassan; Yoonessi, Ali

2017-01-01

Introduction: Mild Cognitive Impairment (MCI), a disorder of the elderly people, is difficult to diagnose and often progresses to Alzheimer Disease (AD). Temporal region is one of the initial areas, which gets impaired in the early stage of AD. Therefore, auditory cortical evoked potential could be a valuable neuromarker for detecting MCI and AD. Methods: In this study, the thresholds of Auditory Steady-State Response (ASSR) to 40 Hz and 80 Hz were compared between Alzheimer Disease (AD), MCI, and control groups. A total of 42 patients (12 with AD, 15 with MCI, and 15 elderly normal controls) were tested for ASSR. Hearing thresholds at 500, 1000, and 2000 Hz in both ears with modulation rates of 40 and 80 Hz were obtained. Results: Significant differences in normal subjects were observed in estimated ASSR thresholds with 2 modulation rates in 3 frequencies in both ears. However, the difference was significant only in 500 Hz in the MCI group, and no significant differences were observed in the AD group. In addition, significant differences were observed between the normal subjects and AD patients with regard to the estimated ASSR thresholds with 2 modulation rates and 3 frequencies in both ears. A significant difference was observed between the normal and MCI groups at 2000 Hz, too. An increase in estimated 40 Hz ASSR thresholds in patients with AD and MCI suggests neural changes in auditory cortex compared to that in normal ageing. Conclusion: Auditory threshold estimation with low and high modulation rates by ASSR test could be a potentially helpful test for detecting cognitive impairment. PMID:29158880

Dependence of cavitation, chemical effect, and mechanical effect thresholds on ultrasonic frequency.

PubMed

Thanh Nguyen, Tam; Asakura, Yoshiyuki; Koda, Shinobu; Yasuda, Keiji

2017-11-01

Cavitation, chemical effect, and mechanical effect thresholds were investigated in wide frequency ranges from 22 to 4880kHz. Each threshold was measured in terms of sound pressure at fundamental frequency. Broadband noise emitted from acoustic cavitation bubbles was detected by a hydrophone to determine the cavitation threshold. Potassium iodide oxidation caused by acoustic cavitation was used to quantify the chemical effect threshold. The ultrasonic erosion of aluminum foil was conducted to estimate the mechanical effect threshold. The cavitation, chemical effect, and mechanical effect thresholds increased with increasing frequency. The chemical effect threshold was close to the cavitation threshold for all frequencies. At low frequency below 98kHz, the mechanical effect threshold was nearly equal to the cavitation threshold. However, the mechanical effect threshold was greatly higher than the cavitation threshold at high frequency. In addition, the thresholds of the second harmonic and the first ultraharmonic signals were measured to detect bubble occurrence. The threshold of the second harmonic approximated to the cavitation threshold below 1000kHz. On the other hand, the threshold of the first ultraharmonic was higher than the cavitation threshold below 98kHz and near to the cavitation threshold at high frequency. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of Socioeconomic Status and Underlying Disease on the Association between Ambient Temperature and Ischemic Stroke.

PubMed

Cho, Seong Kyung; Sohn, Jungwoo; Cho, Jaelim; Noh, Juhwan; Ha, Kyoung Hwa; Choi, Yoon Jung; Pae, Sangjoon; Kim, Changsoo; Shin, Dong Chun

2018-07-01

Inconsistent findings have been reported regarding the effect of ambient temperature on ischemic stroke. Furthermore, little is known about how underlying disease and low socioeconomic status influence the association. We, therefore, investigated the relationship between ambient temperature and emergency department (ED) visits for ischemic stroke, and aimed to identify susceptible populations. Using medical claims data, we identified ED visits for ischemic stroke during 2005-2009 in Seoul, Korea. We conducted piecewise linear regression analyses to find optimum ambient temperature thresholds in summer and winter, and estimated the relative risks (RR) and 95% confidence intervals (CI) per a 1°C increase in temperature above/below the thresholds, adjusting for relative humidity, holidays, day of the week, and air pollutant levels. There were 63564 ED visits for ischemic stroke. In summer, the risk of ED visits for ischemic stroke was not significant, with the threshold at 26.8°C. However, the RRs were 1.055 (95% CI, 1.006-1.106) above 25.0°C in medical aid beneficiaries and 1.044 (1.007-1.082) above 25.8°C in patients with diabetes. In winter, the risk of ED visits for ischemic stroke significantly increased as the temperature decreased above the threshold at 7.2°C. This inverse association was significant also in patients with hypertension and diabetes mellitus above threshold temperatures. Ambient temperature increases above a threshold were positively associated with ED visits for ischemic stroke in patients with diabetes and medical aid beneficiaries in summer. In winter, temperature, to a point, and ischemic stroke visits were inversely associated. © Copyright: Yonsei University College of Medicine 2018.

The anticonvulsant action of nafimidone on kindled amygdaloid seizures in rats.

PubMed

Albertson, T E; Walby, W F

1988-01-01

The anticonvulsant effectiveness of nafimidone (1-[2-naphthoylmethyl]imidazole hydrochloride) was evaluated in the kindled amygdaloid seizure model in rats. Nafimidone (3.1-120 mg/kg i.p.) was evaluated at 30 min in previously kindled rats using both threshold (20 microA increments) and supranthreshold (400 microA) paradigms. Nafimidone (25-50 mg/kg) significantly reduced supranthreshold elicited afterdischarge length and seizure severity only at doses with some prestimulation toxicity. The maximum anticonvulsant effectiveness for the 25 mg/kg i.p. dose of nafimidone was seen between 15 and 30 min utilizing a suprathreshold kindling paradigm. Nafimidone did not significantly elevate seizure thresholds at the doses tested; however, nafimidone (3.1-50 mg/kg) reduced the severity and afterdischarge duration of threshold elicited seizures in a non-dose response manner. Drug-induced electroencephalographic spikes were seen in both cortex and amygdala in most kindled rats receiving 100-120 mg/kg i.p. within 30 min of dosing before electrical stimulation. The frequency of spike and wave complexes increased in most of these animals leading to drug-induced spontaneous seizures and death in approximately 25% before electrical stimulation. This study has demonstrated that although nafimidone can modify both threshold and suprathreshold elicited kindled amygdaloid seizures, it lacks significant specificity in this model of epilepsy.

A comparison of the antinociceptive effects of xylazine, detomidine and romifidine on experimental pain in horses.

PubMed

Moens, Yves; Lanz, Francisca; Doherr, Marcus G; Schatzmann, Urs

2003-07-01

To study the analgesic potency of the alpha2-agonist romifidine in the horse using both an electrical current and a mechanical pressure model for nociceptive threshold testing. In addition, a comparison was made with doses of detomidine and xylazine that produce equivalent degrees of sedation. Randomized, placebo-controlled, blinded cross-over study. Six adult Swiss warmblood horses, one mare and five geldings, weighing from 530 to 650 kg and aged 6-15 years. Nociceptive thresholds were measured using an electrical stimulus applied to the coronary band and using a pneumatically operated pin pressing on the cannon bone. Measurements were made immediately before and every 15 minutes for 2 hours after IV injection of the test substances. Lifting of the foot indicated the test end point. The three alpha2-agonists caused a temporary increase in nociceptive thresholds with a maximal effect within 15 minutes and a return to baseline levels within 1 hour. Using electrical current testing nociceptive thresholds were significantly different from placebo (mean +/- SD) for detomidine at 15 minutes (from control 5.8 +/- 0.9 to 23.3 +/- 3.9 mA, p = 0.0066) and 30 minutes (from control 6.6 +/- 1.1 to 18.8 +/- 3.3 mA, p = 0.0091). The difference was significant for romifidine at 15 minutes only (from control 5.8 +/- 0.9 to 18.7 +/- 3.8 mA, p = 0.0066). With mechanical pressure testing nociceptive thresholds were significantly different from control for detomidine at 15 minutes (from 3.2 +/- 0.2 to 6.2 +/- 0.5 N, p = 0.00076) and 30 minutes (from 3.2 +/- 0.7 to 5.7 +/- 0.8 N, p = 0.0167). The difference was significant for xylazine at 15 minutes (from control 3.2 +/- 0.2 to 5.6 +/- 0.7 N, p = 0.0079). At 15 minutes the order of magnitude of the measured antinociceptive effect was significantly different between the two pain tests for both romifidine and detomidine, but not for xylazine. For romifidine, the increase of mean thresholds compared to placebo was 4.0 +/- 1.3 times placebo levels with the electrical current test compared to 1.3 +/- 0.3 times for the mechanical pressure test (p = 0.037). For detomidine, the increase of mean thresholds compared to placebo was 5.4 +/- 1.7 times control levels with the electrical current test compared to 2.0 +/- 0.2 times for the mechanical pressure test (p = 0.040). This represents a 2.7 (romifidine) and 3.4 times (detomidine) greater increase in thresholds using electrical current testing compared to the use of mechanical pressure testing. This study demonstrates the analgesic potential of alpha2-agonists in the horse for somatic pain and that they can have quantitatively different antinociceptive effects according to the antinociceptive test used.

Effects of tubing length and coupling method on hearing threshold and real-ear to coupler difference measures.

PubMed

Gustafson, Samantha; Pittman, Andrea; Fanning, Robert

2013-06-01

This tutorial demonstrates the effects of tubing length and coupling type (i.e., foam tip or personal earmold) on hearing threshold and real-ear-to-coupler difference (RECD) measures. Hearing thresholds from 0.25 kHz through 8 kHz are reported at various tubing lengths for 28 normal-hearing adults between the ages of 22 and 31 years. RECD values are reported for 14 of the adults. All measures were made with an insert earphone coupled to a standard foam tip and with an insert earphone coupled to each participant's personal earmold. Threshold and RECD measures obtained with a personal earmold were significantly different from those obtained with a foam tip on repeated measures analyses of variance. One-sample t tests showed these differences to vary systematically with increasing tubing length, with the largest average differences (7-8 dB) occurring at 4 kHz. This systematic examination demonstrates the equal and opposite effects of tubing length on threshold and acoustic measures. Specifically, as tubing length increased, sound pressure level in the ear canal decreased, affecting both hearing thresholds and the real-ear portion of the RECDs. This demonstration shows that when the same coupling method is used to obtain the hearing thresholds and RECD, equal and accurate estimates of real-ear sound pressure level are obtained.

No-threshold dose-response curves for nongenotoxic chemicals: Findings and applications for risk assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheehan, Daniel M.

2006-01-15

We tested the hypothesis that no threshold exists when estradiol acts through the same mechanism as an active endogenous estrogen. A Michaelis-Menten (MM) equation accounting for response saturation, background effects, and endogenous estrogen level fit a turtle sex-reversal data set with no threshold and estimated the endogenous dose. Additionally, 31 diverse literature dose-response data sets were analyzed by adding a term for nonhormonal background; good fits were obtained but endogenous dose estimations were not significant due to low resolving power. No thresholds were observed. Data sets were plotted using a normalized MM equation; all 178 data points were accommodated onmore » a single graph. Response rates from {approx}1% to >95% were well fit. The findings contradict the threshold assumption and low-dose safety. Calculating risk and assuming additivity of effects from multiple chemicals acting through the same mechanism rather than assuming a safe dose for nonthresholded curves is appropriate.« less

Lower-Order Compensation Chain Threshold-Reduction Technique for Multi-Stage Voltage Multipliers.

PubMed

Dell' Anna, Francesco; Dong, Tao; Li, Ping; Wen, Yumei; Azadmehr, Mehdi; Casu, Mario; Berg, Yngvar

2018-04-17

This paper presents a novel threshold-compensation technique for multi-stage voltage multipliers employed in low power applications such as passive and autonomous wireless sensing nodes (WSNs) powered by energy harvesters. The proposed threshold-reduction technique enables a topological design methodology which, through an optimum control of the trade-off among transistor conductivity and leakage losses, is aimed at maximizing the voltage conversion efficiency (VCE) for a given ac input signal and physical chip area occupation. The conducted simulations positively assert the validity of the proposed design methodology, emphasizing the exploitable design space yielded by the transistor connection scheme in the voltage multiplier chain. An experimental validation and comparison of threshold-compensation techniques was performed, adopting 2N5247 N-channel junction field effect transistors (JFETs) for the realization of the voltage multiplier prototypes. The attained measurements clearly support the effectiveness of the proposed threshold-reduction approach, which can significantly reduce the chip area occupation for a given target output performance and ac input signal.

Statistical analysis of effective singular values in matrix rank determination

NASA Technical Reports Server (NTRS)

Konstantinides, Konstantinos; Yao, Kung

1988-01-01

A major problem in using SVD (singular-value decomposition) as a tool in determining the effective rank of a perturbed matrix is that of distinguishing between significantly small and significantly large singular values to the end, conference regions are derived for the perturbed singular values of matrices with noisy observation data. The analysis is based on the theories of perturbations of singular values and statistical significance test. Threshold bounds for perturbation due to finite-precision and i.i.d. random models are evaluated. In random models, the threshold bounds depend on the dimension of the matrix, the noisy variance, and predefined statistical level of significance. Results applied to the problem of determining the effective order of a linear autoregressive system from the approximate rank of a sample autocorrelation matrix are considered. Various numerical examples illustrating the usefulness of these bounds and comparisons to other previously known approaches are given.

Acute analgesic effects of nicotine and tobacco in humans: a meta-analysis.

PubMed

Ditre, Joseph W; Heckman, Bryan W; Zale, Emily L; Kosiba, Jesse D; Maisto, Stephen A

2016-07-01

Although animal models have consistently demonstrated acute pain inhibitory effects of nicotine and tobacco, human experimental studies have yielded mixed results. The main goal of this meta-analysis was to quantify the effects of nicotine/tobacco administration on human experimental pain threshold and tolerance ratings. A search of PubMed and PsycINFO online databases identified 13 eligible articles, including k = 21 tests of pain tolerance (N = 393) and k = 15 tests of pain threshold (N = 339). Meta-analytic integration for both threshold and tolerance outcomes revealed that nicotine administered through tobacco smoke and other delivery systems (eg, patch, nasal spray) produced acute analgesic effects that may be characterized as small to medium in magnitude (Hedges g = 0.35, 95% confidence interval = 0.21-0.50). Publication bias-corrected estimates remained significant and indicated that these effects may be closer to small. Sex composition was observed to be a significant moderator, such that pain threshold effects were more robust among samples that included more men than women. These results help to clarify a mixed literature and may ultimately help to inform the treatment of both pain and nicotine dependence. Pain and tobacco smoking are both highly prevalent and comorbid conditions. Current smoking has been associated with more severe chronic pain and physical impairment. Acute nicotine-induced analgesia could make smoking more rewarding and harder to give up. Future research should use dynamic measures of experimental pain reactivity and further explore biopsychosocial mechanisms of action.

Systemic immunity influences hearing preservation in cochlear implantation.

PubMed

Souter, Melanie; Eastwood, Hayden; Marovic, Paul; Kel, Gordana; Wongprasartsuk, Sarin; Ryan, Allen F; O'Leary, Stephen John

2012-06-01

To determine whether a systemic immune response influences hearing thresholds and tissue response after cochlear implantation of hearing guinea pigs. Guinea pigs were inoculated with sterile antigen (Keyhole limpet hemocyanin) 3 weeks before cochlear implantation. Pure-tone auditory brainstem response thresholds were performed before implantation and 1 and 4 weeks later. Dexamethasone phosphate 20% was adsorbed onto a hyaluronic acid carboxymethylcellulose sponge and was applied to the round window for 30 minutes before electrode insertion. Normal saline was used for controls. Cochlear histology was performed at 4 weeks after implantation to assess the tissue response to implantation. To control for the effect of keyhole limpet hemocyanin priming, a group of unprimed animals underwent cochlear implantation with a saline-soaked pledget applied to the round window. Keyhole limpet hemocyanin priming had no significant detrimental effect on thresholds without implantation. Thresholds were elevated after implantation across all frequencies tested (2-32 kHz) in primed animals but only at higher frequencies (4-32 kHz) in unprimed controls. In primed animals, dexamethasone treatment significantly reduced threshold shifts at 2 and 8 kHz. Keyhole limpet hemocyanin led to the more frequent observation of lymphocytes in the tissue response to the implant. Systemic immune activation at the time of cochlear implantation broadened the range of frequencies experiencing elevated thresholds after implantation. Local dexamethasone provides partial protection against this hearing loss, but the degree and extent of protection are less compared to previous studies with unprimed animals.

Effect of intrathecal baclofen on evoked pain perception: an evoked potentials and quantitative thermal testing study.

PubMed

Kumru, H; Kofler, M; Flores, M C; Portell, E; Robles, V; Leon, N; Vidal, J

2013-08-01

Somatic antinociceptive effects of baclofen have been demonstrated in animal models. We hypothesized that if enhanced thermal or pain sensitivity is produced by loss of gamma-aminobutyric acid (GABA)-ergic tone in the central nervous system, spinal administration of GABA agonists might be predicted to be effective in thermal and/or pain perception changes and pain-related evoked potentials in candidates for intrathecal baclofen (ITB) treatment. Eleven patients with severe spinal cord injury (SCI) who suffered from severe spasticity were evaluated during a 50-μg ITB bolus test. Warm and heat pain thresholds, evoked heat pain perception, and contact heat-evoked potentials (CHEPs) were determined above SCI level from the right and left sides. Nine age- and gender-matched healthy volunteers undergoing repeat testing without any placebo injection served as control group. In patients, heat pain perception threshold increased, and evoked pain perception and amplitude of CHEPs decreased significantly after ITB bolus application in comparison with baseline (p < 0.005), with no change in warm perception threshold. In controls, no significant changes were observed in repeat testing over time. Our findings indicate that ITB modulates heat pain perception threshold, evoked heat pain perception and heat pain-related evoked potentials without inducing warm perception threshold changes in SCI patients. This phenomenon should be taken into account in the clinical evaluation and management of pain in patients receiving baclofen. © 2012 European Federation of International Association for the Study of Pain Chapters.

Low concentrations of procaine and diethylaminoethanol reduce the excitability but not the action potential amplitude of hippocampal pyramidal cells.

PubMed

Butterworth, J F; Cole, L R

1990-10-01

To determine whether concentrations of diethylaminoethanol (DEAE) and procaine below those that reduce the amplitude of action potentials might alter the excitability of brain cells, a single microelectrode intracellular recording technique was used to measure firing threshold and action potential amplitude of pyramidal cells in rat hippocampal slices. At low concentrations of both DEAE (less than or equal to 5 mM) and procaine (less than or equal to 0.5 mM), firing threshold was significantly increased (P less than 0.01), whereas action potential spike amplitude was minimally altered. At higher concentrations, both drugs significantly decreased action potential spike amplitude (P less than 0.025) as well as increased firing threshold (P less than 0.001). Diethylaminoethanol tended to increase threshold relatively more than procaine, when drug concentrations that similarly reduced action potential amplitude were compared. All actions of DEAE and procaine were reversible. Inhibition of action potentials by DEAE and procaine was clearly concentration-dependent (P less than or equal to 0.015). Diethylaminoethanol effects on threshold were marginally concentration-dependent (P = 0.08); procaine did not demonstrate clear concentration-dependent effects (P = 0.33) over the concentrations tested in this study. These similar actions of procaine and DEAE on brain cells suggest a mechanism by which intravenous local anesthetics may contribute to the general anesthetic state. Moreover, it appears possible that procaine metabolism and DEAE accumulation may underlie the prolonged effects sometimes seen after intravenous procaine administration.

Effects of Sex and Stress on Trigeminal Neuropathic Pain-Like Behavior in Rats.

PubMed

Korczeniewska, Olga Anna; Khan, Junad; Tao, Yuanxiang; Eliav, Eli; Benoliel, Rafael

2017-01-01

To investigate the effects and interactions of sex and stress (provoked by chronic restraint [RS]) on pain-like behavior in a rat model of trigeminal neuropathic pain. The effects of sex and RS (carried out for 14 days as a model for stress) on somatosensory measures (reaction to pinprick, von Frey threshold) in a rat model of trigeminal neuropathic pain were examined. The study design was 2 × 4, with surgery (pain) and sham surgery (no pain) interacting with male restrained (RS) and unrestrained (nRS) rats and female RS and nRS rats. A total of 64 Sprague Dawley rats (32 males and 32 females) were used. Half of the animals in each sex group underwent RS, and the remaining half were left unstressed. Following the RS period, trigeminal neuropathic pain was induced by unilateral infraorbital nerve chronic constriction injury (IOCCI). Half of the animals in the RS group and half in the nRS group (both males and females) were exposed to IOCCI, and the remaining halves to sham surgery. Elevated plus maze (EPM) assessment and plasma interferon gamma (IFN-γ) levels were used to measure the effects of RS. Analysis of variance (ANOVA) was used to assess the effects of stress, sex, and their interactions on plasma IFN-γ levels, changes in body weight, EPM parameters, tactile allodynia, and mechanohyperalgesia. Pairwise comparisons were performed by using Tukey post hoc test corrected for multiple comparisons. Both male and female RS rats showed significantly altered exploratory behavior (as measured by EPM) and had significantly lower plasma IFN-γ levels than nRS rats. Rats exposed to RS gained weight significantly slower than the nRS rats, irrespective of sex. Following RS but before surgery, RS rats showed significant bilateral reductions in von Frey thresholds and significantly increased pinprick response difference scores compared to nRS rats, irrespective of sex. From 17 days postsurgery, RSIOCCI rats showed significantly reduced von Frey thresholds and significantly increased pinprick response difference scores compared to nRS-IOCCI rats, and the von Frey thresholds were significantly lower in females than in males. RS-sham females-but not RS-sham males-developed persistently reduced thresholds and increased pinprick response difference scores. RS produced an increased bilateral sensitivity to stimuli applied to the vibrissal pad following infraorbital nerve injury, irrespective of sex. This observed sensitivity subsequently persisted in RS-sham female rats but not in RS-sham male rats. Stress induced a significant but moderate increase in pain-like behavior in female rats compared to male rats. RS had no significant sex effects on IFN-γ levels, EPM parameters, or body weight gain. This suggests that stress may have a selective effect on pain-like behavior in both sexes, but the possible mechanisms are unclear.

Weight bearing of the limb as a confounding factor in assessment of mechanical allodynia in the rat.

PubMed

Kauppila, T; Kontinen, V K; Pertovaara, A

1998-01-01

Effect of weight bearing of the hindlimbs on the assessment of mechanically-induced hindlimb withdrawal threshold was determined in intact rats and in rats with various pathophysiological conditions causing allodynia or hyperalgesia. Hindlimb withdrawal was elicited by applying a series of calibrated monofilaments to the plantar or the dorsal surface of the paw. During testing the rat was either in a restraint tube with hindlimbs hanging semi-extended without weight bearing or it was standing on a metal grid (bearing its own weight). In intact rats, the withdrawal thresholds were significantly lower when the stimulus site was the dorsal hairy skin rather than the plantar glabrous skin. Also, thresholds were significantly lower when the hindlimbs were not bearing weight. Following carrageenan-induced unilateral inflammation of the plantar paw or a tibial nerve cut there was a marked threshold decrease to test stimuli applied to plantar or dorsal paw, respectively, ipsilateral to the pathological condition in standing rats. However, when the hindlimbs were not weight bearing the unilateral threshold decrease was markedly attenuated (carrageenan-treated rats) or completely abolished (tibial cut). In contrast, in rats with a unilateral spinal nerve ligation the threshold decrease ipsilateral to the nerve lesion was highly significant independent of the weight bearing of the hindlimbs. The results indicate that weight bearing of hindlimbs is an important confounding factor in the assessment of tactile allodynia in rats.

Steroid treatment of posttraumatic anosmia.

PubMed

Jiang, Rong-San; Wu, Shang-Heng; Liang, Kai-Li; Shiao, Jiun-Yih; Hsin, Chung-Han; Su, Mao-Chang

2010-10-01

The objective of this study was to treat posttraumatic anosmia with oral steroid and evaluate its effect. One-hundred sixteen posttraumatic patients whose olfactory thresholds were -1.0 by the phenyl ethyl alcohol threshold test assembled in our department. They were treated with a course of high-dose steroid, and followed up for at least 3 months. During the latter period of this study, magnetic resonance imaging was performed to measure the volumes of olfactory bulbs and to detect subfrontal lobe damage. Among them, 19 (16.4%) patients' olfactory thresholds improved after steroid treatment, but the other 97 patients' thresholds did not change. The incidences of loss of consciousness and intracranial hemorrhage after head injury, the ratios of admission and craniotomy, the intervals between head injury and steroid treatment, the volumes of olfactory bulbs, and the incidences of subfrontal lobe damage were not significantly different between patients whose thresholds improved and those whose thresholds did not improve. However, patients with olfactory improvement were significantly younger than those who remained unchanged. Our study showed that oral steroid treatment might improve olfactory acuity in some patients with posttraumatic anosmia, but the possibility of spontaneous recovery cannot be ruled out.

Logistics of air medical transport: When and where does helicopter transport reduce prehospital time for trauma?

PubMed

Chen, Xilin; Gestring, Mark L; Rosengart, Matthew R; Peitzman, Andrew B; Billiar, Timothy R; Sperry, Jason L; Brown, Joshua B

2018-05-04

Trauma is a time sensitive disease. Helicopter emergency medical services (HEMS) have shown benefit over ground EMS (GEMS), which may be related to reduced prehospital time. The distance at which this time benefit emerges depends on many factors that can vary across regions. Our objective was to determine the threshold distance at which HEMS has shorter prehospital time than GEMS under different conditions. Patients in the PA trauma registry 2000-2013 were included. Distance between zip centroid and trauma center was calculated using straight-line distance for HEMS and driving distance from GIS network analysis for GEMS. Contrast margins from linear regression identified the threshold distance at which HEMS had a significantly lower prehospital time than GEMS, indicated by non-overlapping 95% confidence intervals. The effect of peak traffic times and adverse weather on the threshold distance was evaluated. Geographic effects across EMS regions were also evaluated. A total of 144,741 patients were included with 19% transported by HEMS. Overall, HEMS became faster than GEMS at 7.7miles from the trauma center (p=0.043). HEMS became faster at 6.5miles during peak traffic (p=0.025) compared to 7.9miles during off-peak traffic (p=0.048). Adverse weather increased the distance at which HEMS was faster to 17.1miles (p=0.046) from 7.3miles in clear weather (p=0.036). Significant variation occurred across EMS regions, with threshold distances ranging from 5.4miles to 35.3miles. There was an inverse but non-significant relationship between urban population and threshold distance across EMS regions (ρ -0.351, p=0.28). This is the first study to demonstrate that traffic, weather, and geographic region significantly impact the threshold distance at which HEMS is faster than GEMS. HEMS was faster at shorter distances during peak traffic while adverse weather increased this distance. The threshold distance varied widely across geographic region. These factors must be considered to guide appropriate HEMS triage protocols. III, Therapeutic.

The earth is flat (p > 0.05): significance thresholds and the crisis of unreplicable research

PubMed Central

Korner-Nievergelt, Fränzi; Roth, Tobias

2017-01-01

The widespread use of ‘statistical significance’ as a license for making a claim of a scientific finding leads to considerable distortion of the scientific process (according to the American Statistical Association). We review why degrading p-values into ‘significant’ and ‘nonsignificant’ contributes to making studies irreproducible, or to making them seem irreproducible. A major problem is that we tend to take small p-values at face value, but mistrust results with larger p-values. In either case, p-values tell little about reliability of research, because they are hardly replicable even if an alternative hypothesis is true. Also significance (p ≤ 0.05) is hardly replicable: at a good statistical power of 80%, two studies will be ‘conflicting’, meaning that one is significant and the other is not, in one third of the cases if there is a true effect. A replication can therefore not be interpreted as having failed only because it is nonsignificant. Many apparent replication failures may thus reflect faulty judgment based on significance thresholds rather than a crisis of unreplicable research. Reliable conclusions on replicability and practical importance of a finding can only be drawn using cumulative evidence from multiple independent studies. However, applying significance thresholds makes cumulative knowledge unreliable. One reason is that with anything but ideal statistical power, significant effect sizes will be biased upwards. Interpreting inflated significant results while ignoring nonsignificant results will thus lead to wrong conclusions. But current incentives to hunt for significance lead to selective reporting and to publication bias against nonsignificant findings. Data dredging, p-hacking, and publication bias should be addressed by removing fixed significance thresholds. Consistent with the recommendations of the late Ronald Fisher, p-values should be interpreted as graded measures of the strength of evidence against the null hypothesis. Also larger p-values offer some evidence against the null hypothesis, and they cannot be interpreted as supporting the null hypothesis, falsely concluding that ‘there is no effect’. Information on possible true effect sizes that are compatible with the data must be obtained from the point estimate, e.g., from a sample average, and from the interval estimate, such as a confidence interval. We review how confusion about interpretation of larger p-values can be traced back to historical disputes among the founders of modern statistics. We further discuss potential arguments against removing significance thresholds, for example that decision rules should rather be more stringent, that sample sizes could decrease, or that p-values should better be completely abandoned. We conclude that whatever method of statistical inference we use, dichotomous threshold thinking must give way to non-automated informed judgment. PMID:28698825

CHANGES IN THE ANAEROBIC THRESHOLD IN AN ANNUAL CYCLE OF SPORT TRAINING OF YOUNG SOCCER PLAYERS

PubMed Central

Andrzejewski, M.; Wieczorek, A.; Barinow-Wojewódzki, A.; Jadczak, Ł.; Adrian, S.; Pietrzak, M.; Wieczorek, S.

2013-01-01

The aim of the study was to assess changes in the anaerobic threshold of young soccer players in an annual training cycle. A group of highly trained 15-18 year old players of KKS Lech Poznań were tested. The tests included an annual training macrocycle, and its individual stages resulted from the time structure of the sports training. In order to assess the level of exercise capacities of the players, a field exercise test of increasing intensity was carried out on a soccer pitch. The test made it possible to determine the 4 millimolar lactate threshold (T LA 4 mmol · l-1) on the basis of the lactate concentration in blood [LA], to establish the threshold running speed and the threshold heart rate [HR]. The threshold running speed at the level of the 4 millimolar lactate threshold was established using the two-point form of the equation of a straight line. The obtained indicators of the threshold running speed allowed for precise establishment of effort intensity used in individual training in developing aerobic endurance. In order to test the significance of differences in mean values between four dates of tests, a non-parametric Friedman ANOVA test was used. The significance of differences between consecutive dates of tests was determined using a post-hoc Friedman ANOVA test. The tests showed significant differences in values of selected indicators determined at the anaerobic threshold in various stages of an annual training cycle of young soccer players. The most beneficial changes in terms of the threshold running speed were noted on the fourth date of tests, when the participants had the highest values of 4.01 m · s-1 for older juniors, and 3.80 m · s-1 for younger juniors. This may be indicative of effective application of an individualized programme of training loads and of good preparation of teams for competition in terms of players’ aerobic endurance. PMID:24744480

Changes in the anaerobic threshold in an annual cycle of sport training of young soccer players.

PubMed

Sliwowski, R; Andrzejewski, M; Wieczorek, A; Barinow-Wojewódzki, A; Jadczak, L; Adrian, S; Pietrzak, M; Wieczorek, S

2013-06-01

The aim of the study was to assess changes in the anaerobic threshold of young soccer players in an annual training cycle. A group of highly trained 15-18 year old players of KKS Lech Poznań were tested. The tests included an annual training macrocycle, and its individual stages resulted from the time structure of the sports training. In order to assess the level of exercise capacities of the players, a field exercise test of increasing intensity was carried out on a soccer pitch. The test made it possible to determine the 4 millimolar lactate threshold (T LA 4 mmol · l(-1)) on the basis of the lactate concentration in blood [LA], to establish the threshold running speed and the threshold heart rate [HR]. The threshold running speed at the level of the 4 millimolar lactate threshold was established using the two-point form of the equation of a straight line. The obtained indicators of the threshold running speed allowed for precise establishment of effort intensity used in individual training in developing aerobic endurance. In order to test the significance of differences in mean values between four dates of tests, a non-parametric Friedman ANOVA test was used. The significance of differences between consecutive dates of tests was determined using a post-hoc Friedman ANOVA test. The tests showed significant differences in values of selected indicators determined at the anaerobic threshold in various stages of an annual training cycle of young soccer players. The most beneficial changes in terms of the threshold running speed were noted on the fourth date of tests, when the participants had the highest values of 4.01 m · s(-1) for older juniors, and 3.80 m · s(-1) for younger juniors. This may be indicative of effective application of an individualized programme of training loads and of good preparation of teams for competition in terms of players' aerobic endurance.

Effect of morphine, methadone, hydromorphone or oxymorphone on the thermal threshold, following intravenous or buccal administration to cats.

PubMed

Pypendop, Bruno H; Shilo-Benjamini, Yael; Ilkiw, Jan E

2016-11-01

To determine the effects of morphine, methadone, hydromorphone or oxymorphone on the thermal threshold in cats, following buccal and intravenous (IV) administration. Randomized crossover study. Six healthy adult female ovariohysterectomized cats weighing 4.5 ± 0.4 kg. Morphine sulfate (0.2 mg kg -1 IV or 0.5 mg kg -1 buccal), methadone hydrochloride (0.3 mg kg -1 IV or 0.75 mg kg -1 buccal), hydromorphone hydrochloride (0.1 mg kg -1 IV or 0.25 mg kg -1 buccal) or oxymorphone hydrochloride (0.1 mg kg -1 IV or 0.25 mg kg -1 buccal) were administered. All cats were administered all treatments. Skin temperature and thermal threshold were measured in duplicate prior to drug administration, and at various times up to 8 hours after drug administration. The difference between thermal threshold and skin temperature (ΔT) was analyzed. Administration of methadone and hydromorphone IV resulted in significant increases in ΔT at 40 minutes after drug administration. Buccal administration of methadone resulted in significant increases in thermal threshold, although no significant difference from baseline measurement was detected at any time point. IV administration of morphine and oxymorphone, and buccal administration of morphine, hydromorphone and oxymorphone did not cause significant thermal antinociception. At the doses used in this study, IV administration of methadone and hydromorphone, and buccal administration of methadone resulted in transient thermal antinociception. The results of this study do not allow us to predict the usefulness of these drugs for providing analgesia in clinical patients. © 2016 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

[Protective effect of indirect activator of calcium pump on noise-induced hearing loss].

PubMed

Liu, Jun; Yu, Ning; Han, Dongyi; Yang, Weiyan; Li, Xingqi

2002-12-01

To investigate the possible protective effect of phorbol-12-myristate-13-acetate (PMA), an activator of protein kinase C (PKC) and indirect activator of Ca2+ pump, on noise-induced hearing loss (NIHL). Twenty guinea pigs were divided randomly into two groups, and then perfused with artificial perilymph solutions in one group and with artificial perilymph solutions containing 3 mumol/L PMA in the other one, respectively. All animals were exposed with 100 dB SPL white noise for 2 hours. Cochlear microphonics (CM) and compound action potential (CAP) were recorded from the round window (RW) before noise exposure and 2 hours after noise exposure. There was no significant difference in CAP threshold and CM amplitude between two groups before noise exposure. A significant difference was observed in CAP threshold and CM amplitude between two groups after noise exposure. The amplitude of CM decreased and the threshold of CAP increased in both group after noise exposure, but in the PMA group the decrease of the amplitude of CM was higher while the increase of threshold of CAP lower than that in control (P < 0.05). PMA might have partly protective effect on NIHL. These findings indirectly proved that intracellular Ca2+ overload might involve in the mechanism of NIHL.

The effect of target-controlled infusion of low-dose ketamine on heat pain and temporal summation threshold.

PubMed

Lee, Joon-Ho; Cho, Sung-Hwan; Kim, Sang-Hyun; Chae, Won-Soek; Jin, Hee-Cheol; Lee, Jeong-Seok; Kim, Yong-Ik

2011-08-01

We investigated the heat pain threshold (HPT) and temporal summation threshold (TST) before and after target-controlled infusion (TCI) of ketamine with an effect-site concentration (Ce) of 30 and 60 ng/ml. Healthy young volunteers (n = 20) were enrolled. A thermode was applied to the volar side of each volunteer's right forearm, and HPT and TST were measured before and after TCI of ketamine. Vital signs and psychedelic effects according to ketamine infusion were also observed before and after TCI of ketamine. Mean HPT after TCI of ketamine with a Ce of 30 and 60 ng/ml did not increase significantly. However, mean TST after TCI of ketamine with a Ce of 30 and 60 ng/ml increased significantly, in a dose-dependent fashion, compared with the value before ketamine TCI. Vital signs showed no significant difference before and after ketamine TCI. The visual analog scale score of psychedelic symptoms was higher with a Ce of 60 ng/ml than with 30 ng/ml. TCI of ketamine with a Ce of 30 and 60 ng/ml increased TST but not HPT.

The Insignificance of Thresholds in Environmental Impact Assessment: An Illustrative Case Study in Canada

NASA Astrophysics Data System (ADS)

Murray, Cathryn Clarke; Wong, Janson; Singh, Gerald G.; Mach, Megan; Lerner, Jackie; Ranieri, Bernardo; Peterson St-Laurent, Guillaume; Guimaraes, Alice; Chan, Kai M. A.

2018-06-01

Environmental assessment is the process that decision-makers rely on to predict, evaluate, and prevent biophysical, social, and economic impacts of potential project developments. The determination of significance in environmental assessment is central to environmental management in many nations. We reviewed ten recent environmental impact assessments from British Columbia, Canada and systematically reviewed and scored significance determination and the approaches used by assessors, the use of thresholds in significance determination, threshold exceedances, and the outcomes. Findings of significant impacts were exceedingly rare and practitioners used a combination of significance determination approaches, most commonly relying upon reasoned argumentation. Quantitative thresholds were rarely employed, with less than 10% of the valued components evaluated using thresholds. Even where quantitative thresholds for significance were exceeded, in every case practitioners used a variety of rationales to demote negative impacts to non-significance. These reasons include combinations of scale (temporal and spatial) of impacts, an already exceeded baseline, model uncertainty and/or substituting less stringent thresholds. Governments and agencies can better protect resources by requiring clear and defensible significance determinations, by making government-defined thresholds legally enforceable and accountable, and by requiring or encouraging significance determination through inclusive and collaborative approaches.

A comparison of the ability of a 4:1 ketogenic diet and a 6.3:1 ketogenic diet to elevate seizure thresholds in adult and young rats.

PubMed

Nylen, Kirk; Likhodii, Sergei; Abdelmalik, Peter A; Clarke, Jasper; Burnham, W McIntyre

2005-08-01

The pentylenetetrazol (PTZ) infusion test was used to compare seizure thresholds in adult and young rats fed either a 4:1 ketogenic diet (KD) or a 6.3:1 KD. We hypothesized that both KDs would significantly elevate seizure thresholds and that the 4:1 KD would serve as a better model of the KD used clinically. Ninety adult rats and 75 young rats were placed on one of five experimental diets: (a) a 4:1 KD, (b) a control diet balanced to the 4:1 KD, (c) a 6.3:1 KD, (d) a standard control diet, or (e) an ad libitum standard control diet. All subjects were seizure tested by using the PTZ infusion test. Blood glucose and beta-hydroxybutyrate (beta-OHB) levels were measured. Neither KD elevated absolute "latencies to seizure" in young or adult rats. Similarly, neither KD elevated "threshold doses" in adult rats. In young rats, the 6.3:1 KD, but not the 4:1 KD, significantly elevated threshold doses. The 6.3:1 KD group showed poorer weight gain than the 4:1 KD group when compared with respective controls. The most dramatic discrepancies were seen in young rats. "Threshold doses" and "latency to seizure" data provided conflicting measures of seizure threshold. This was likely due to the inflation of threshold doses calculated by using the much smaller body weights found in the 6.3:1 KD group. Ultimately, the PTZ infusion test in rats may not be a good preparation to model the anticonvulsant effects of the KD seen clinically, especially when dietary treatments lead to significantly mismatched body weights between the groups.

Lowering of acoustic droplet vaporization threshold via aggregation

NASA Astrophysics Data System (ADS)

Guo, Shifang; Shi, Aiwei; Xu, Shanshan; Du, Xuan; Wang, Xin; Zong, Yujin; Bouakaz, Ayache; Wan, Mingxi

2017-12-01

Acoustically sensitive emulsion nanodroplets composed of perfluorocarbon have shown great potential for advanced medical diagnosis and therapy but are limited by the required high acoustic droplet vaporization (ADV) threshold for clinical applications. This study investigates the use of an ultrasonic standing wave to lower the ADV threshold while maintaining the generated bubble size in the required size range, ensuring the generation of inertial cavitation and corresponding physical effects. The results showed that disperse nanodroplets were manipulated to form micron-sized aggregations, and the required ADV threshold was significantly lowered, while a similar size range of the microbubbles generated by disperse nanodroplets was maintained. The threshold could be further regulated by adjusting the aggregation size via controlling the concentration of the disperse nanodroplets. Furthermore, the internal pressures in the aggregations with different sizes were calculated to determine their ADV thresholds theoretically, which were shown to be in good agreement with the experimental results.

The immediate effects of sigmoid colon manipulation on pressure pain thresholds in the lumbar spine.

PubMed

McSweeney, Terence P; Thomson, Oliver P; Johnston, Ross

2012-10-01

Visceral manual therapy is increasingly used by UK osteopaths and manual therapists, but there is a paucity of research investigating its underlying mechanisms, and in particular in relation to hypoalgesia. The aim of this study was to investigate the immediate effects of osteopathic visceral mobilisation on pressure pain thresholds. A single-blinded, randomised, within subjects, repeated measures design was conducted on 15 asymptomatic subjects. Pressure pain thresholds were measured at the L1 paraspinal musculature and 1st dorsal interossei before and after osteopathic visceral mobilisation of the sigmoid colon. The results demonstrated a statistically significant improvement in pressure pain thresholds immediately after the intervention (P<0.001). This effect was not observed to be systemic, affecting only the L1 paraspinal musculature. This novel study provides new experimental evidence that visceral manual therapy can produce immediate hypoalgesia in somatic structures segmentally related to the organ being mobilised, in asymptomatic subjects. Copyright © 2012. Published by Elsevier Ltd.

Effect of laryngotracheal topical anesthesia on recurrent laryngeal nerve monitoring during thyroid Surgery.

PubMed

Pachuski, Justin; Vaida, Sonia; Donahue, Kathleen; Roberts, John; Kunselman, Allen; Oberman, Benjamin; Patel, Hetal; Goldenberg, David

2016-03-01

Intraoperative neuromonitoring of the recurrent laryngeal nerve (RLN) is often used as an adjunct for RLN identification and preservation during thyroidectomies. Laryngotracheal anesthesia (LTA) with topical lidocaine reduces coughing upon emergence from anesthesia and in the immediate postoperative period; however, its use is prohibited with concerns that it could decrease the sensitivity of the intraoperative neuromonitoring. We hypothesize that there is no difference in measurements of nerve conduction made before and after LTA administration. An observational study in which all patients were subjected to LTA administration was conducted. Recurrent laryngeal nerve threshold currents were measured before and after the intervention. Tertiary medical center operating room. Eighteen patients (total of 25 nerves at risk) with American Society of Anesthesiologists classes 1 to 3 undergoing thyroid surgery. After the thyroid was removed and threshold currents at the RLN were obtained, LTA with endotracheal lidocaine was applied on the left and right side of the in situ endotracheal tube (2 cc of 4% lidocaine per side). Threshold currents were reassessed at 5 and 10 minutes after LTA administration. Threshold currents (minimum stimulus current applied to the RLN required to generate a discernible electromyographic response at the vocal cords) were recorded along the RLN for a baseline at 5 and 10 mm from the insertion point of the RLN into the larynx. Threshold currents were reassessed at the same 2 positions on the RLN at 5 and 10 minutes after LTA administration. Differences in mean values, between threshold currents recorded at the 3 different times, at 2 positions on the RLN, were used to compare effects of LTA on nerve conduction. There were no statistically significant differences when comparing threshold currents before and after LTA administration. Laryngotracheal anesthesia had no significant effect on RLN nerve conduction in the period assessed. Copyright © 2016 Elsevier Inc. All rights reserved.

Eccentric muscle damage has variable effects on motor unit recruitment thresholds and discharge patterns in elbow flexor muscles.

PubMed

Dartnall, Tamara J; Rogasch, Nigel C; Nordstrom, Michael A; Semmler, John G

2009-07-01

The purpose of this study was to determine the effect of eccentric muscle damage on recruitment threshold force and repetitive discharge properties of low-threshold motor units. Ten subjects performed four tasks involving isometric contraction of elbow flexors while electromyographic (EMG) data were recorded from human biceps brachii and brachialis muscles. Tasks were 1) maximum voluntary contraction (MVC); 2) constant-force contraction at various submaximal targets; 3) motor unit recruitment threshold task; and 4) minimum motor unit discharge rate task. These tasks were performed on three separate days before, immediately after, and 24 h after eccentric exercise of elbow flexor muscles. MVC force declined (42%) immediately after exercise and remained depressed (29%) 24 h later, indicative of muscle damage. Mean motor unit recruitment threshold for biceps brachii was 8.4+/-4.2% MVC, (n=34) before eccentric exercise, and was reduced by 41% (5.0+/-3.0% MVC, n=34) immediately after and by 39% (5.2+/-2.5% MVC, n=34) 24 h after exercise. No significant changes in motor unit recruitment threshold were observed in the brachialis muscle. However, for the minimum tonic discharge rate task, motor units in both muscles discharged 11% faster (10.8+/-2.0 vs. 9.7+/-1.7 Hz) immediately after (n=29) exercise compared with that before (n=32). The minimum discharge rate variability was greater in brachialis muscle immediately after exercise (13.8+/-3.1%) compared with that before (11.9+/-3.1%) and 24 h after exercise (11.7+/-2.4%). No significant changes in minimum discharge rate variability were observed in the biceps brachii motor units after exercise. These results indicate that muscle damage from eccentric exercise alters motor unit recruitment thresholds for >or=24 h, but the effect is not the same in the different elbow flexor muscles.

Assessment of the discomfort threshold of command board operators in automated productions with respect to its application in professional selection.

PubMed

Tzaneva, L

1996-09-01

The discomfort threshold problem is not yet clear from the audiological point of view. Its significance for work physiology and hygiene is not enough clarified. This paper discussed the results of a study of the discomfort threshold, performed including 385 operators from the State Company "Kremikovtzi", divided into 4 groups (3 groups according to length of service and one control group). The most prominent changes were found in operators with increased tonal auditory threshold up to 45 and over 50 dB with high confidential probability. The observed changes are distributed in 3 groups: 1. increased tonal auditory threshold (up to 30 dB) without decrease of the discomfort threshold; 2. decreased discomfort threshold (with about 15-20 dB) at increased tonal auditory threshold (up to 45 dB); 3. decreased discomfort threshold at increased (over 50 dB) tonal auditory threshold. The auditory scope of the operators, belonging to groups III and IV (with the longest length of service) is narrowed, being distorted for the latter. This pathophysiological phenomenon can be explained by an enhanced effect of sound irritation and the presence of a recruitment phenomenon with possible engagement of the central part of the auditory analyzer. It is concluded that the discomfort threshold is a sensitive indicator for the state of the individual norms for speech-sound-noise discomfort. The comparison of the discomfort threshold with the hygienic standards and the noise levels at each particular working place can be used as a criterion for the professional selection for work in conditions of masking noise effect and its tolerance with respect to achieving the individual discomfort level depending on the intensity of the speech-sound-noise signals at a particular working place.

Transverse Instabilities in the Fermilab Recycler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prost, L.R.; Burov, A.; Shemyakin, A.

2011-07-01

Transverse instabilities of the antiproton beam have been observed in the Recycler ring soon after its commissioning. After installation of transverse dampers, the threshold for the instability limit increased significantly but the instability is still found to limit the brightness of the antiprotons extracted from the Recycler for Tevatron shots. In this paper, we describe observations of the instabilities during the extraction process as well as during dedicated studies. The measured instability threshold phase density agrees with the prediction of the rigid beam model within a factor of 2. Also, we conclude that the instability threshold can be significantly loweredmore » for a bunch contained in a narrow and shallow potential well due to effective exclusion of the longitudinal tails from Landau damping.« less

Vestibular Evoked Myogenic Potential (VEMP) Testing: Normative Threshold Response Curves and Effects of Age

PubMed Central

Janky, Kristen L.; Shepard, Neil

2009-01-01

Background Vestibular Evoked Myogenic Potential (VEMP) testing has gained increased interest in the diagnosis of a variety of vestibular etiologies. Comparisons of P13 / N23 latency, amplitude and threshold response curves have been used to compare pathologic groups to normal controls. Appropriate characterization of these etiologies requires normative data across the frequency spectrum and age range. Purpose The objective of the current study was to test the hypothesis that significant changes in VEMP responses occur as a function of increased age across all test stimuli as well as characterize the VEMP threshold response curve across age. Research Design This project incorporated a prospective study design using a sample of convenience. Openly recruited subjects were assigned to groups according to age. Study Sample Forty-six normal controls ranging between 20 and 76 years of age participated in the study. Participants were separated by decade into 5 age categories from 20 to 60 plus years. Normal participants were characterized by having normal hearing sensitivity, no history of neurologic or balance/dizziness involvement and negative results on a direct office vestibular examination. Intervention VEMP responses were measured at threshold to click and 250, 500, 750, and 1000 Hz tone burst stimuli and at a suprathreshold level to 500 Hz toneburst stimuli at123 dBSPL. Data Collection and Analysis A mixed group factorial ANOVA and linear regression were performed to examine the effects of VEMP characteristics upon age. Results There were no significant differences between ears for any of the test parameters. There were no significant differences between age groups for n23 latency or amplitude in response to any of the stimuli. Significant mean differences did exist between age groups for p13 latency (250, 750, and 1000 Hz) and threshold (500 and 750 Hz). Age was significantly correlated with VEMP parameters. VEMP threshold was positively correlated (250, 500, 750, 1000 Hz); and amplitude was negatively correlated (500 Hz Maximum). The threshold response curves revealed best frequency tuning at 500 Hz with the highest thresholds in response to click stimuli. However, this best frequency tuning dissipated with increased age. VEMP response rates also decreased with increased age. Conclusion We have demonstrated that minor differences in VEMP responses occur with age. Given the reduced response rates and flattened frequency tuning curve for individuals over the age of 60, frequency tuning curves may not be a good diagnostic indicator for this age group. PMID:19764171

Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

NASA Technical Reports Server (NTRS)

Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

1989-01-01

The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

Effect of strong fragrance on olfactory detection threshold.

PubMed

Fasunla, Ayotunde James; Douglas, David Dayo; Adeosun, Aderemi Adeleke; Steinbach, Silke; Nwaorgu, Onyekwere George Benjamin

2014-09-01

To assess the olfactory threshold of healthy volunteers at the University College Hospital, Ibadan and to investigate the effect of perfume on their olfactory detection thresholds. A quasi-experimental study on olfactory detection thresholds of healthy volunteers from September 2013 to November 2013. Tertiary health institution. A structured questionniare was administered to the participants in order to obtain information on sociodemographics, occupation, ability to perceive smell, use of perfume, effects of perfume on appetite and self-confidence, history of allergy, and previous nasal surgery. Participants subjectively rated their olfactory performance. Subsequently, they had olfactory detection threshold testing done at baseline and after exposure to perfume with varied concentrations of n-butanol in a forced triple response and staircase fashion. Healthy volunteers, 37 males and 63 females, were evaluated. Their ages ranged from 19 to 59 years with a mean of 31 years ± 8. Subjectively, 94% of the participants had excellent olfactory function. In the pre-exposure forced triple response, 88% were able to detect the odor at ≤.25 mmol/l concentration while in the post-exposure forced triple response, only 66% were able to detect the odor at ≤.25 mmol/l concentration. There is also a statistical significant difference in the olfactory detection threshold score between the pre-exposure and post-exposure period in the participants (P < .05). Use of strong fragrances affects the olfactory detection threshold. Therefore patients and clinicians should be aware of this and its effects on the outcome of test of olfaction. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.

Impairment of retinal increment thresholds in Huntington's disease.

PubMed

Paulus, W; Schwarz, G; Werner, A; Lange, H; Bayer, A; Hofschuster, M; Müller, N; Zrenner, E

1993-10-01

We have investigated detection thresholds for a foveal blue test light using a Maxwellian view system in 61 normal subjects, 19 patients with Huntington's chorea, 14 patients with Tourette's syndrome, and 20 patients with schizophrenia. Ten measurements were made: The blue test light (1 degree diameter, 500 msec duration) was presented either superimposed on a yellow adaptation field (5 degree diameter) or 500 msec after switching off this field (transient tritanopia effect). In both cases five different background intensities were presented. The only abnormality found was in patients with Huntington's chorea. During adaptation these patients' thresholds are significantly higher than normal (p < 0.005). No change was found in the transient tritanopia effect. Huntington's disease causes degeneration of several different transmitter systems in the brain. Increment threshold testing allows for noninvasive investigation of patients and confirms the involvement of the retina in the degenerative process in Huntington's chorea.

Temporal integration property of stereopsis after higher-order aberration correction

PubMed Central

Kang, Jian; Dai, Yun; Zhang, Yudong

2015-01-01

Based on a binocular adaptive optics visual simulator, we investigated the effect of higher-order aberration correction on the temporal integration property of stereopsis. Stereo threshold for line stimuli, viewed in 550nm monochromatic light, was measured as a function of exposure duration, with higher-order aberrations uncorrected, binocularly corrected or monocularly corrected. Under all optical conditions, stereo threshold decreased with increasing exposure duration until a steady-state threshold was reached. The critical duration was determined by a quadratic summation model and the high goodness of fit suggested this model was reasonable. For normal subjects, the slope for stereo threshold versus exposure duration was about −0.5 on logarithmic coordinates, and the critical duration was about 200 ms. Both the slope and the critical duration were independent of the optical condition of the eye, showing no significant effect of higher-order aberration correction on the temporal integration property of stereopsis. PMID:26601010

A low threshold nanocavity in a two-dimensional 12-fold photonic quasicrystal

NASA Astrophysics Data System (ADS)

Ren, Jie; Sun, XiaoHong; Wang, Shuai

2018-05-01

In this article, a low threshold nanocavity is built and investigated in a two-dimensional 12-fold holographic photonic quasicrystal (PQC). The cavity is formed by using the method of multi-beam common-path interference. By finely adjusting the structure parameters of the cavity, the Q factor and the mode volume are optimized, which are two keys to low-threshold on the basis of Purcell effect. Finally, an optimal cavity is obtained with Q value of 6023 and mode volume of 1.24 ×10-12cm3 . On the other hand, by Fourier Transformation of the electric field components in the cavity, the in-plane wave vectors are calculated and fitted to evaluate the cavity performance. The performance analysis of the cavity further proves the effectiveness of the optimization process. This has a guiding significance for the research of low threshold nano-laser.

Ethnic differences in thermal pain responses: a comparison of South Asian and White British healthy males.

PubMed

Watson, Paul J; Latif, R Khalid; Rowbotham, David J

2005-11-01

The expression and report of pain is influenced by social environment and culture. Previous studies have suggested ethnically determined differences in report of pain threshold, intensity and affect. The influence of ethnic differences between White British and South Asians has remained unexplored. Twenty age-matched, male volunteers in each group underwent evaluation. Cold and warm perception and cold and heat threshold were assessed using an ascending method of limits. Magnitude estimation of pain unpleasantness and pain intensity were investigated with thermal stimuli of 46, 47, 48 and 49 degrees C. Subjects also completed a pain anxiety questionnaire. Data was analysed using t-test, Mann-Whitney and repeated measures analysis of variance as appropriate. There were no differences in cold and warm perception between the two groups. There was a statistically significant difference between the two groups for heat pain threshold (P=0.006) and heat pain intensity demonstrated a significant effect for ethnicity (F=13.84, P=0.001). Although no group differences emerged for cold pain threshold and heat unpleasantness, South Asians demonstrated lower cold pain threshold and reported more unpleasantness at all temperatures but this was not statistically significant. Our study shows that ethnicity plays an important role in heat pain threshold and pain report, South Asian males demonstrated lower pain thresholds and higher pain report when compared with matched White British males. There were no differences in pain anxiety between the two groups and no correlations were identified between pain and pain anxiety Haemodynamic measures and anthropometry did not explain group differences.

Neurosensory effects of chronic exposure to arsenic via drinking water in Inner Mongolia: II. Vibrotactile and visual function.

PubMed

Otto, David; He, Linlin; Xia, Yanhong; Li, Yajuan; Wu, Kegong; Ning, Zhixiong; Zhao, Baixiao; Hudnell, H Kenneth; Kwok, Richard; Mumford, Judy; Geller, Andrew; Wade, Timothy

2006-03-01

This study was designed to assess the effects of exposure to arsenic in drinking water on visual and vibrotactile function in residents of the Bamen region of Inner Mongolia, China. Arsenic was measured by hydride generation atomic fluorescence. 321 participants were divided into three exposure groups- low (non-detectable-20), medium (100-300) and high (400-700 microg/l) arsenic in drinking water (AsW). Three visual tests were administered: acuity, contrast sensitivity and color discrimination (Lanthony's Desaturated 15 Hue Test). Vibration thresholds were measured with a vibrothesiometer. Vibration thresholds were significantly elevated in the high exposure group compared to other groups. Further analysis using a spline regression model suggested that the threshold for vibratory effects is between 150-170 microg/l AsW. These findings provide the first evidence that chronic exposure to arsenic in drinking water impairs vibrotactile thresholds. The results also indicate that arsenic affects neurological function well below the 1000 microg/I concentration reported by NRC (1999). No evidence of arsenic-related effects on visual function was found.

Effects of moisture content on wind erosion thresholds of biochar

NASA Astrophysics Data System (ADS)

Silva, F. C.; Borrego, C.; Keizer, J. J.; Amorim, J. H.; Verheijen, F. G. A.

2015-12-01

Biochar, i.e. pyrolysed biomass, as a soil conditioner is gaining increasing attention in research and industry, with guidelines and certifications being developed for biochar production, storage and handling, as well as for application to soils. Adding water to biochar aims to reduce its susceptibility to become air-borne during and after the application to soils, thereby preventing, amongst others, human health issues from inhalation. The Bagnold model has previously been modified to explain the threshold friction velocity of coal particles at different moisture contents, by adding an adhesive effect. However, it is unknown if this model also works for biochar particles. We measured the threshold friction velocities of a range of biochar particles (woody feedstock) under a range of moisture contents by using a wind tunnel, and tested the performance of the modified Bagnold model. Results showed that the threshold friction velocity can be significantly increased by keeping the gravimetric moisture content at or above 15% to promote adhesive effects between the small particles. For the specific biochar of this study, the modified Bagnold model accurately estimated threshold friction velocities of biochar particles up to moisture contents of 10%.

Effect of Heavy Consumption of Alcoholic Beverages on the Perception of Sweet and Salty Taste.

PubMed

Silva, Camile S; Dias, Vaneria R; Almeida, Juliane A Regis; Brazil, Jamile M; Santos, Ramon A; Milagres, Maria P

2016-05-01

To determine the threshold index of sweet and salty tastes in alcoholics undergoing treatment. Taste threshold was assessed using type 3-Alternative Forced Choice in a control group (92 non-alcoholic volunteers) and a test group (92 alcoholics in therapy). The test group completed a structured questionnaire on lifestyle and habits. Significant difference were found between the threshold rates found in the test (3.78) and control groups (1.39). In the salty stimulus, no significant difference was noted in the threshold detection between the control (0.17) and test groups (0.30). A significant correlation was observed between the index Pearson's threshold to sweet taste in the test group and their reported alcohol consumption. The test group reported characteristics such as loss of appetite (93%), weight loss during consumption (62%) and weight gain after quitting drinking (72%). That the alcoholic group reported less sensitivity to sweet taste suggests that drinking habits may influence choice of foods, with a greater preference for foods with higher sucrose concentration. This contribute to poor health, because excess consumption of sugar raises risk for several diseases. No conclusive results were found for the salty stimulus. © The Author 2015. Medical Council on Alcohol and Oxford University Press. All rights reserved.

Peaks Over Threshold (POT): A methodology for automatic threshold estimation using goodness of fit p-value

NASA Astrophysics Data System (ADS)

Solari, Sebastián.; Egüen, Marta; Polo, María. José; Losada, Miguel A.

2017-04-01

Threshold estimation in the Peaks Over Threshold (POT) method and the impact of the estimation method on the calculation of high return period quantiles and their uncertainty (or confidence intervals) are issues that are still unresolved. In the past, methods based on goodness of fit tests and EDF-statistics have yielded satisfactory results, but their use has not yet been systematized. This paper proposes a methodology for automatic threshold estimation, based on the Anderson-Darling EDF-statistic and goodness of fit test. When combined with bootstrapping techniques, this methodology can be used to quantify both the uncertainty of threshold estimation and its impact on the uncertainty of high return period quantiles. This methodology was applied to several simulated series and to four precipitation/river flow data series. The results obtained confirmed its robustness. For the measured series, the estimated thresholds corresponded to those obtained by nonautomatic methods. Moreover, even though the uncertainty of the threshold estimation was high, this did not have a significant effect on the width of the confidence intervals of high return period quantiles.

Comparison of Pain Thresholds and Analgesic Effects of Parecoxib Sodium in Surgical Patients of Different Racial and Religious Backgrounds.

PubMed

Li, Li-Biao; Hu, Yu; Liu, Chao; Gu, Miao-Ning

2015-06-01

To explore the differences of the thresholds of pain and analgesic effects of parecoxib sodium among patients with different racial and religious backgrounds. A total of 48 male patients aged 18 to 38 years who had undergone elective laparoscopic appendectomy under general anesthesia in our centers were enrolled in our study and then divided into 6 groups(n=8 in each group)based on their racial backgrounds(three levels:Mongoloid,Negroid,and Europoid)and religious backgrounds(two levels:without religion background,with religion background).All subjects received the same anesthesia,surgical procedure,and postoperative analgesia with parecoxib sodium. The temperature pain threshold and electrical pain threshold were detected 1h before and after analgesia. The threshold of pain was higher in Europoids than in Negroids and Mongoloids before and after treatment. The temperature pain threshold and electrical pain threshold were not significantly different between subjects with or without religious background(before analgesic therapy:F=251.119,P=0.130,F=275.861,P=0.059;after analgesic therapy:F=308.531,P=0.086,F=180.062,P=0.078). Also,there was no interaction between the racial and religious backgrous in terms of temperature pain threshold and electrical pain threshold(F=13.553,P=0.091,F=22.001,P= 0.089;after analgesic therapy:F=4.624,P=0.089,F=15.935,P=0.094). The threshold of pain differs among individuals with different racial background:it is highest in Europoids,followed by Negroids and Mongoloids. It shows no obvious difference in people with different religious backgrounds.

Influence of taekwondo as security martial arts training on anaerobic threshold, cardiorespiratory fitness, and blood lactate recovery.

PubMed

Kim, Dae-Young; Seo, Byoung-Do; Choi, Pan-Am

2014-04-01

[Purpose] This study was conducted to determine the influence of Taekwondo as security martial arts training on anaerobic threshold, cardiorespiratory fitness, and blood lactate recovery. [Subjects and Methods] Fourteen healthy university students were recruited and divided into an exercise group and a control group (n = 7 in each group). The subjects who participated in the experiment were subjected to an exercise loading test in which anaerobic threshold, value of ventilation, oxygen uptake, maximal oxygen uptake, heart rate, and maximal values of ventilation / heart rate were measured during the exercise, immediately after maximum exercise loading, and at 1, 3, 5, 10, and 15 min of recovery. [Results] At the anaerobic threshold time point, the exercise group showed a significantly longer time to reach anaerobic threshold. The exercise group showed significantly higher values for the time to reach VO2max, maximal values of ventilation, maximal oxygen uptake and maximal values of ventilation / heart rate. Significant changes were observed in the value of ventilation volumes at the 1- and 5-min recovery time points within the exercise group; oxygen uptake and maximal oxygen uptake were significantly different at the 5- and 10-min time points; heart rate was significantly different at the 1- and 3-min time points; and maximal values of ventilation / heart rate was significantly different at the 5-min time point. The exercise group showed significant decreases in blood lactate levels at the 15- and 30-min recovery time points. [Conclusion] The study results revealed that Taekwondo as a security martial arts training increases the maximal oxygen uptake and anaerobic threshold and accelerates an individual's recovery to the normal state of cardiorespiratory fitness and blood lactate level. These results are expected to contribute to the execution of more effective security services in emergencies in which violence can occur.

Rainfall thresholds and susceptibility mapping for shallow landslides and debris flows in Scotland

NASA Astrophysics Data System (ADS)

Postance, Benjamin; Hillier, John; Dijkstra, Tom; Dixon, Neil

2017-04-01

Shallow translational slides and debris flows (hereafter 'landslides') pose a significant threat to life and cause significant annual economic impacts (e.g. by damage and disruption of infrastructure). The focus of this research is on the definition of objective rainfall thresholds using a weather radar system and landslide susceptibility mapping. In the study area Scotland, an inventory of 75 known landslides was used for the period 2003 to 2016. First, the effect of using different rain records (i.e. time series length) on two threshold selection techniques in receiver operating characteristic (ROC) analysis was evaluated. The results show that thresholds selected by 'Threat Score' (minimising false alarms) are sensitive to rain record length and which is not routinely considered, whereas thresholds selected using 'Optimal Point' (minimising failed alarms) are not; therefore these may be suited to establishing lower limit thresholds and be of interest to those developing early warning systems. Robust thresholds are found for combinations of normalised rain duration and accumulation at 1 and 12 day's antecedence respectively; these are normalised using the rainy-day normal and an equivalent measure for rain intensity. This research indicates that, in Scotland, rain accumulation provides a better indicator than rain intensity and that landslides may be generated by threshold conditions lower than previously thought. Second, a landslide susceptibility map is constructed using a cross-validated logistic regression model. A novel element of the approach is that landslide susceptibility is calculated for individual hillslope sections. The developed thresholds and susceptibility map are combined to assess potential hazards and impacts posed to the national highway network in Scotland.

Influence of intrinsic noise generated by a thermotesting device on thermal sensory detection and thermal pain detection thresholds.

PubMed

Pavlaković, G; Züchner, K; Zapf, A; Bachmann, C G; Graf, B M; Crozier, T A; Pavlaković, H

2009-08-01

Various factors can influence thermal perception threshold measurements and contribute significantly to unwanted variability of the tests. To minimize this variability, testing should be performed under strictly controlled conditions. Identifying the factors that increase the variability and eliminating their influence should increase reliability and reproducibility. Currently available thermotesting devices use a water-cooling system that generates a continuous noise of approximately 60 dB. In order to analyze whether this noise could influence the thermal threshold measurements we compared the thresholds obtained with a silent thermotesting device to those obtained with a commercially available device. The subjects were tested with one randomly chosen device on 1 day and with the other device 7 days later. At each session, heat, heat pain, cold, and cold pain thresholds were determined with three measurements. Bland-Altman analysis was used to assess agreement in measurements obtained with different devices and it was shown that the intersubject variability of the thresholds obtained with the two devices was comparable for all four thresholds tested. In contrast, the intrasubject variability of the thresholds for heat, heat pain, and cold pain detection was significantly lower with the silent device. Our results show that thermal sensory thresholds measured with the two devices are comparable. However, our data suggest that, for studies with repeated measurements on the same subjects, a silent thermotesting device may allow detection of smaller differences in the treatment effects and/or may permit the use of a smaller number of tested subjects. Muscle Nerve 40: 257-263, 2009.

The influence of trait anxiety and illusory kinesthesia on pain threshold.

PubMed

Imai, Ryota; Osumi, Michihiro; Ishigaki, Tomoya; Morioka, Shu

2017-07-01

[Purpose] It has also been reported that decreased activity in the reward pathway causes a decrease in brain activity in the descending pain control system in people with high trait anxiety. Activation of this system is dependent on both the reward pathway and motor areas. Recently, studies have also shown that motor areas are activated by illusory kinesthesia. It was aimed to explore whether anxiety trait modulates the influence of illusory kinesthesia on pain threshold. [Subjects and Methods] The pain threshold and trait anxiety at rest before vibratory tendon stimulation (the task) were measured. After the task, the pain threshold, the illusory kinesthesia angle, and the intensity of illusory kinesthesia for patients with and without illusory kinesthesia were measured. A total of 35 healthy right-handed students participated, among whom 22 and 13 were included in the illusion and no-illusion groups, respectively. [Results] There was a significant increase in the pain threshold after task completion in both groups; however, there was no statistically significant difference between the two groups. Correlational analysis revealed that State-Trait Anxiety Inventory-trait score correlated negatively with the pain threshold in the no-illusion group, but there was no correlation in the illusion group. [Conclusion] The pain threshold improved regardless of the size of trait anxiety in the illusion group, but did not improve merely through sensory input by vibratory stimulation in the no-illusion group. Thus, illusory kinesthesia has effect of increasing the pain threshold.

Effects of Transcutaneous Electrical Nerve Stimulation on Pain, Pain Sensitivity, and Function in People With Knee Osteoarthritis: A Randomized Controlled Trial

PubMed Central

Vance, Carol Grace T.; Rakel, Barbara A.; Blodgett, Nicole P.; DeSantana, Josimari Melo; Amendola, Annunziato; Zimmerman, Miriam Bridget; Walsh, Deirdre M.

2012-01-01

Background Transcutaneous electrical nerve stimulation (TENS) is commonly used for the management of pain; however, its effects on several pain and function measures are unclear. Objective The purpose of this study was to determine the effects of high-frequency TENS (HF-TENS) and low-frequency TENS (LF-TENS) on several outcome measures (pain at rest, movement-evoked pain, and pain sensitivity) in people with knee osteoarthritis. Design The study was a double-blind, randomized clinical trial. Setting The setting was a tertiary care center. Participants Seventy-five participants with knee osteoarthritis (29 men and 46 women; 31–94 years of age) were assessed. Intervention Participants were randomly assigned to receive HF-TENS (100 Hz) (n=25), LF-TENS (4 Hz) (n=25), or placebo TENS (n=25) (pulse duration=100 microseconds; intensity=10% below motor threshold). Measurements The following measures were assessed before and after a single TENS treatment: cutaneous mechanical pain threshold, pressure pain threshold (PPT), heat pain threshold, heat temporal summation, Timed “Up & Go” Test (TUG), and pain intensity at rest and during the TUG. A linear mixed-model analysis of variance was used to compare differences before and after TENS and among groups (HF-TENS, LF-TENS, and placebo TENS). Results Compared with placebo TENS, HF-TENS and LF-TENS increased PPT at the knee; HF-TENS also increased PPT over the tibialis anterior muscle. There was no effect on the cutaneous mechanical pain threshold, heat pain threshold, or heat temporal summation. Pain at rest and during the TUG was significantly reduced by HF-TENS, LF-TENS, and placebo TENS. Limitations This study tested only a single TENS treatment. Conclusions Both HF-TENS and LF-TENS increased PPT in people with knee osteoarthritis; placebo TENS had no significant effect on PPT. Cutaneous pain measures were unaffected by TENS. Subjective pain ratings at rest and during movement were similarly reduced by active TENS and placebo TENS, suggesting a strong placebo component of the effect of TENS. PMID:22466027

Assessing the Role of Place and Timing Cues in Coding Frequency and Amplitude Modulation as a Function of Age.

PubMed

Whiteford, Kelly L; Kreft, Heather A; Oxenham, Andrew J

2017-08-01

Natural sounds can be characterized by their fluctuations in amplitude and frequency. Ageing may affect sensitivity to some forms of fluctuations more than others. The present study used individual differences across a wide age range (20-79 years) to test the hypothesis that slow-rate, low-carrier frequency modulation (FM) is coded by phase-locked auditory-nerve responses to temporal fine structure (TFS), whereas fast-rate FM is coded via rate-place (tonotopic) cues, based on amplitude modulation (AM) of the temporal envelope after cochlear filtering. Using a low (500 Hz) carrier frequency, diotic FM and AM detection thresholds were measured at slow (1 Hz) and fast (20 Hz) rates in 85 listeners. Frequency selectivity and TFS coding were assessed using forward masking patterns and interaural phase disparity tasks (slow dichotic FM), respectively. Comparable interaural level disparity tasks (slow and fast dichotic AM and fast dichotic FM) were measured to control for effects of binaural processing not specifically related to TFS coding. Thresholds in FM and AM tasks were correlated, even across tasks thought to use separate peripheral codes. Age was correlated with slow and fast FM thresholds in both diotic and dichotic conditions. The relationship between age and AM thresholds was generally not significant. Once accounting for AM sensitivity, only diotic slow-rate FM thresholds remained significantly correlated with age. Overall, results indicate stronger effects of age on FM than AM. However, because of similar effects for both slow and fast FM when not accounting for AM sensitivity, the effects cannot be unambiguously ascribed to TFS coding.

Oxytocin administration selectively improves olfactory detection thresholds for lyral in patients with schizophrenia

PubMed Central

Woolley, J.D.; Lam, O.; Chuang, B.; Ford, J.M.; Mathalon, D.H.; Vinogradov, S.

2015-01-01

Summary Background Olfaction plays an important role in mammalian social behavior. Olfactory deficits are common in schizophrenia and correlate with negative symptoms and low social drive. Despite their prominence and possible clinical relevance, little is understood about the pathological mechanisms underlying olfactory deficits in schizophrenia and there are currently no effective treatments for these deficits. The prosocial neuropeptide oxytocin may affect the olfactory system when administered intranasally to humans and there is growing interest in its therapeutic potential in schizophrenia. Methods To examine this model, we administered 40 IU of oxytocin and placebo intranasally to 31 patients with a schizophrenia spectrum illness and 34 age-matched healthy control participants in a randomized, double-blind, placebo-controlled, cross-over study. On each test day, participants completed an olfactory detection threshold test for two different odors: (1) lyral, a synthetic fragrance compound for which patients with schizophrenia have specific olfactory detection threshold deficits, possibly related to decreased cyclic adenosine 3′,5′-monophosphate (cAMP) signaling; and (2) anise, a compound for which olfactory detection thresholds change with menstrual cycle phase in women. Results On the placebo test day, patients with schizophrenia did not significantly differ from healthy controls in detection of either odor. We found that oxytocin administration significantly and selectively improved olfactory detection thresholds for lyral but not for anise in patients with schizophrenia. In contrast, oxytocin had no effect on detection of either odor in healthy controls. Discussion Our data indicate that oxytocin administration may ameliorate olfactory deficits in schizophrenia and suggest the effects of intranasal oxytocin may extend to influencing the olfactory system. Given that oxytocin has been found to increase cAMP signaling in vitro a possible mechanism for these effects is discussed. PMID:25637811

Oxytocin administration selectively improves olfactory detection thresholds for lyral in patients with schizophrenia.

PubMed

Woolley, J D; Lam, O; Chuang, B; Ford, J M; Mathalon, D H; Vinogradov, S

2015-03-01

Olfaction plays an important role in mammalian social behavior. Olfactory deficits are common in schizophrenia and correlate with negative symptoms and low social drive. Despite their prominence and possible clinical relevance, little is understood about the pathological mechanisms underlying olfactory deficits in schizophrenia and there are currently no effective treatments for these deficits. The prosocial neuropeptide oxytocin may affect the olfactory system when administered intranasally to humans and there is growing interest in its therapeutic potential in schizophrenia. To examine this model, we administered 40IU of oxytocin and placebo intranasally to 31 patients with a schizophrenia spectrum illness and 34 age-matched healthy control participants in a randomized, double-blind, placebo-controlled, cross-over study. On each test day, participants completed an olfactory detection threshold test for two different odors: (1) lyral, a synthetic fragrance compound for which patients with schizophrenia have specific olfactory detection threshold deficits, possibly related to decreased cyclic adenosine 3',5'-monophosphate (cAMP) signaling; and (2) anise, a compound for which olfactory detection thresholds change with menstrual cycle phase in women. On the placebo test day, patients with schizophrenia did not significantly differ from healthy controls in detection of either odor. We found that oxytocin administration significantly and selectively improved olfactory detection thresholds for lyral but not for anise in patients with schizophrenia. In contrast, oxytocin had no effect on detection of either odor in healthy controls. Our data indicate that oxytocin administration may ameliorate olfactory deficits in schizophrenia and suggest the effects of intranasal oxytocin may extend to influencing the olfactory system. Given that oxytocin has been found to increase cAMP signaling in vitro a possible mechanism for these effects is discussed. Published by Elsevier Ltd.

SU-D-9A-02: Relative Effects of Threshold Choice and Spatial Resolution Modeling On SUV and Volume Quantification in F18-FDG PET Imaging of Anal Cancer Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, F; Shandong Cancer Hospital and Insititute, Jinan, Shandong; Bowsher, J

2014-06-01

Purpose: PET imaging with F18-FDG is utilized for treatment planning, treatment assessment, and prognosis. A region of interest (ROI) encompassing the tumor may be determined on the PET image, often by a threshold T on the PET standard uptake values (SUVs). Several studies have shown prognostic value for relevant ROI properties including maximum SUV value (SUVmax), metabolic tumor volume (MTV), and total glycolytic activity (TGA). The choice of threshold T may affect mean SUV value (SUVmean), MTV, and TGA. Recently spatial resolution modeling (SRM) has been introduced on many PET systems. SRM may also affect these ROI properties. The purposemore » of this work is to investigate the relative influence of SRM and threshold choice T on SUVmean, MTV, TGA, and SUVmax. Methods: For 9 anal cancer patients, 18F-FDG PET scans were performed prior to treatment. PET images were reconstructed by 2 iterations of Ordered Subsets Expectation Maximization (OSEM), with and without SRM. ROI contours were generated by 5 different SUV threshold values T: 2.5, 3.0, 30%, 40%, and 50% of SUVmax. Paired-samples t tests were used to compare SUVmean, MTV, and TGA (a) for SRM on versus off and (b) between each pair of threshold values T. SUVmax was also compared for SRM on versus off. Results: For almost all (57/60) comparisons of 2 different threshold values, SUVmean, MTV, and TGA showed statistically significant variation. For comparison of SRM on versus off, there were no statistically significant changes in SUVmax and TGA, but there were statistically significant changes in MTV for T=2.5 and T=3.0 and in SUVmean for all T. Conclusion: The near-universal statistical significance of threshold choice T suggests that, regarding harmonization across sites, threshold choice may be a greater concern than choice of SRM. However, broader study is warranted, e.g. other iterations of OSEM should be considered.« less

The effect of short-term training on cardinal and oblique orientation discrimination: an ERP study.

PubMed

Song, Yan; Sun, Li; Wang, You; Zhang, Xuemin; Kang, Jing; Ma, Xiaoli; Yang, Bin; Guan, Yijie; Ding, Yulong

2010-03-01

The adult brain shows remarkable plasticity, as demonstrated by the improvement in most visual discrimination tasks after intensive practice. However, previous studies have demonstrated that practice improved the discrimination only around oblique orientations, while performance around cardinal orientations (vertical or horizontal orientations) remained stable despite extensive training. The two experiments described here used event-related potentials (ERPs) to investigate the neural substrates underlying different training effects in the two kinds of orientation. Event-related potentials were recorded from subjects when they were trained with a grating orientation discrimination task. Psychophysical threshold measurements were performed before and after the training. For oblique gratings, psychophysical thresholds decreased significantly across training sessions. ERPs showed larger P2 and P3 amplitudes and smaller N1 amplitudes over the parietal/occipital areas with more practice. In line with the psychophysical thresholds, the training effect on the P2 and P3 was specific to stimulus orientation. However, the N1 effect was generalized over differently oriented gratings stimuli. For cardinally oriented gratings, no significant changes were found in the psychophysical thresholds during the training. ERPs still showed similar generalized N1 effect as the oblique gratings. However, the amplitudes of P2 and P3 were unchanged during the whole training. Compared with cardinal orientations, more visual processing stages and later ERP components were involved in the training of oblique orientation discrimination. These results contribute to understanding the neural basis of the asymmetry between cardinal and oblique orientation training effects. Copyright 2009 Elsevier B.V. All rights reserved.

The effect of prolonged standing on touch sensitivity threshold of the foot: a pilot study.

PubMed

Wiggermann, Neal E; Werner, Robert A; Keyserling, W Monroe

2012-02-01

To determine the effect of prolonged standing on touch sensitivity of the foot. An observational study with replications. University laboratory. Ten healthy college students (5 men and 5 women), with a mean ± SD age of 23.5 ± 4.1 years and body mass of 67.4 ± 12.6 kg. Semmes-Weinstein monofilament tests were administered to 12 locations on the dorsal and plantar surfaces of the foot before and after 4 hours of standing. These locations were formed into several groupings (toes, metatarsal heads, midfoot, heel, all plantar sites, all dorsal sites), and paired t-tests were used to test for significant changes in sensitivity threshold after standing. The difference between sensitivity thresholds measured before and after standing for different locations on the foot. The average of all sensitivity thresholds on the plantar surface of the foot decreased (indicating increased sensitivity) from 0.56 to 0.36 g (P < .01) after 4 hours of prolonged standing. This change in threshold equated to a difference of 1 Semmes-Weinstein monofilament level. Changes in the sensitivity threshold of the dorsal aspect of the foot were not significant. Analysis of the results suggests that the plantar foot has greater sensitivity to touch after prolonged standing. These findings may be useful for identifying potential unintended bias in clinical touch sensitivity testing. Future research is necessary to understand the underlying mechanisms for this sensitivity change and to determine the onset and recovery times for sensitivity changes. Copyright © 2012 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Economic evaluation and cost-effectiveness thresholds: signals to firms and implications for R & D investment and innovation.

PubMed

Vernon, John A; Goldberg, Robert; Golec, Joseph

2009-01-01

In this article we describe how reimbursement cost-effectiveness thresholds, per unit of health benefit, whether set explicitly or observed implicitly via historical reimbursement decisions, serve as a signal to firms about the commercial viability of their R&D projects (including candidate products for in-licensing). Traditional finance methods for R&D project valuations, such as net present value analyses (NPV), incorporate information from these payer reimbursement signals to help determine which R&D projects should be continued and which should be terminated (in the case of the latter because they yield an NPV < 0). Because the influence these signals have for firm R&D investment decisions is so significant, we argue that it is important for reimbursement thresholds to reflect the economic value of the unit of health benefit being considered for reimbursement. Thresholds set too low (below the economic value of the health benefit) will result in R&D investment levels that are too low relative to the economic value of R&D (on the margin). Similarly, thresholds set too high (above the economic value of the health benefit) will result in inefficiently high levels of R&D spending. The US in particular, which represents approximately half of the global pharmaceutical market (based on sales), and which seems poised to begin undertaking cost effectiveness in a systematic way, needs to exert caution in setting policies that explicitly or implicitly establish cost-effectiveness reimbursement thresholds for healthcare products and technologies, such as pharmaceuticals.

Subthalamic deep brain stimulation modulates conscious perception of sensory function in Parkinson's disease.

PubMed

Cury, Rubens G; Galhardoni, Ricardo; Teixeira, Manoel J; Dos Santos Ghilardi, Maria G; Silva, Valquiria; Myczkowski, Martin L; Marcolin, Marco A; Barbosa, Egberto R; Fonoff, Erich T; Ciampi de Andrade, Daniel

2016-12-01

Subthalamic deep brain stimulation (STN-DBS) is used to treat refractory motor complications in Parkinson disease (PD), but its effects on nonmotor symptoms remain uncertain. Up to 80% of patients with PD may have pain relief after STN-DBS, but it is unknown whether its analgesic properties are related to potential effects on sensory thresholds or secondary to motor improvement. We have previously reported significant and long-lasting pain relief after DBS, which did not correlate with motor symptomatic control. Here we present secondary data exploring the effects of DBS on sensory thresholds in a controlled way and have explored the relationship between these changes and clinical pain and motor improvement after surgery. Thirty-seven patients were prospectively evaluated before STN-DBS and 12 months after the procedure compared with healthy controls. Compared with baseline, patients with PD showed lower thermal and mechanical detection and higher cold pain thresholds after surgery. There were no changes in heat and mechanical pain thresholds. Compared with baseline values in healthy controls, patients with PD had higher thermal and mechanical detection thresholds, which decreased after surgery toward normalization. These sensory changes had no correlation with motor or clinical pain improvement after surgery. These data confirm the existence of sensory abnormalities in PD and suggest that STN-DBS mainly influenced the detection thresholds rather than painful sensations. However, these changes may depend on the specific effects of DBS on somatosensory loops with no correlation to motor or clinical pain improvement.

Postural control after a prolonged treadmill run at individual ventilatory and anaerobic threshold.

PubMed

Guidetti, Laura; Franciosi, Emanuele; Gallotta, Maria Chiara; Emerenziani, Gian Pietro; Baldari, Carlo

2011-01-01

The objective of the study was to verify whether young males' balance was affected by 30min prolonged treadmill running (TR) at individual ventilatory (IVT) and anaerobic (IAT) thresholds in recovery time. The VO2max, IAT and IVT during an incremental TR were determined. Mean displacement amplitude (Acp) and velocity (Vcp) of center of pressure were recorded before (pre) and after (0min post; 5min post; and 10min post) prolonged TR at IAT and IVT, through posturographic trials performed with eyes open (EO) and closed (EC). Significant differences between IVT and IAT for Vcp, between EO and EC for Acp and Vcp, were observed. The IAT induced higher destabilizing effect when postural trials were performed with EC. The IVT intensity produced also a destabilizing effect on postural control immediately after exercise. An impairment of postural control after prolonged treadmill running exercise at IVT and IAT intensity was showed. However, destabilizing effect on postural control disappeared within 10min after IAT intensity and within 5min after IVT intensity. Key pointsTo verify whether young males' balance was affected by 30min prolonged treadmill running at individual ventilatory and anaerobic thresholds in recovery time.Mean displacement amplitude and velocity of foot pressure center were recorded before and after prolonged treadmill running at individual ventilatory and anaerobic thresholds, through posturographic trials performed with eyes open and closed.Destabilizing effect on postural control disappeared within 10min post individual anaerobic threshold, and within 5min post individual ventilatory threshold.

Automated Smartphone Threshold Audiometry: Validity and Time Efficiency.

PubMed

van Tonder, Jessica; Swanepoel, De Wet; Mahomed-Asmail, Faheema; Myburgh, Hermanus; Eikelboom, Robert H

2017-03-01

Smartphone-based threshold audiometry with automated testing has the potential to provide affordable access to audiometry in underserved contexts. To validate the threshold version (hearTest) of the validated hearScreen™ smartphone-based application using inexpensive smartphones (Android operating system) and calibrated supra-aural headphones. A repeated measures within-participant study design was employed to compare air-conduction thresholds (0.5-8 kHz) obtained through automated smartphone audiometry to thresholds obtained through conventional audiometry. A total of 95 participants were included in the study. Of these, 30 were adults, who had known bilateral hearing losses of varying degrees (mean age = 59 yr, standard deviation [SD] = 21.8; 56.7% female), and 65 were adolescents (mean age = 16.5 yr, SD = 1.2; 70.8% female), of which 61 had normal hearing and the remaining 4 had mild hearing losses. Threshold comparisons were made between the two test procedures. The Wilcoxon signed-ranked test was used for comparison of threshold correspondence between manual and smartphone thresholds and the paired samples t test was used to compare test time. Within the adult sample, 94.4% of thresholds obtained through smartphone and conventional audiometry corresponded within 10 dB or less. There was no significant difference between smartphone (6.75-min average, SD = 1.5) and conventional audiometry test duration (6.65-min average, SD = 2.5). Within the adolescent sample, 84.7% of thresholds obtained at 0.5, 2, and 4 kHz with hearTest and conventional audiometry corresponded within ≤5 dB. At 1 kHz, 79.3% of the thresholds differed by ≤10 dB. There was a significant difference (p < 0.01) between smartphone (7.09 min, SD = 1.2) and conventional audiometry test duration (3.23 min, SD = 0.6). The hearTest application with calibrated supra-aural headphones provides a cost-effective option to determine valid air-conduction hearing thresholds. American Academy of Audiology

[The analysis of threshold effect using Empower Stats software].

PubMed

Lin, Lin; Chen, Chang-zhong; Yu, Xiao-dan

2013-11-01

In many studies about biomedical research factors influence on the outcome variable, it has no influence or has a positive effect within a certain range. Exceeding a certain threshold value, the size of the effect and/or orientation will change, which called threshold effect. Whether there are threshold effects in the analysis of factors (x) on the outcome variable (y), it can be observed through a smooth curve fitting to see whether there is a piecewise linear relationship. And then using segmented regression model, LRT test and Bootstrap resampling method to analyze the threshold effect. Empower Stats software developed by American X & Y Solutions Inc has a threshold effect analysis module. You can input the threshold value at a given threshold segmentation simulated data. You may not input the threshold, but determined the optimal threshold analog data by the software automatically, and calculated the threshold confidence intervals.

Effects of noise exposure on neonatal auditory brainstem response thresholds in pregnant guinea pigs at different gestational periods.

PubMed

Morimoto, Chihiro; Nario, Kazuhiko; Nishimura, Tadashi; Shimokura, Ryota; Hosoi, Hiroshi; Kitahara, Tadashi

2017-01-01

Noise exposure during pregnancy has been reported to cause fetal hearing impairment. However, little is known about the effects of noise exposure during various gestational stages on postnatal hearing. In the present study, we investigated the effects of noise exposure on auditory brainstem response (ABR) at the early, mid-, and late gestational periods in newborn guinea pigs. Pregnant guinea pigs were exposed to 4-kHz pure tone at a 120-dB sound pressure level for 4 h. We divided the animals into four groups as follows: the control, early gestational exposure, mid-gestational exposure, and late gestational exposure groups. ABR thresholds and latencies in newborns were recorded using 1-, 2-, and 4-kHz tone burst on postnatal days 1, 7, 14, and 28. Changes in ABR thresholds and latencies were measured between the 4 × 4 and 4 × 3 factorial groups mentioned above (gestational periods × postnatal days, gestational periods × frequencies). The thresholds were low in the order of control group < early gestational exposure group < mid-gestational exposure group and late gestational exposure group. Noise exposure during pregnancy influenced ABR thresholds in neonatal guinea pigs. This is the first study to show that noise exposure during the early, mid-, and late gestational periods significantly elevated ABR thresholds in neonatal guinea pigs. © 2016 Japan Society of Obstetrics and Gynecology.

Medico-economic evaluation of healthcare products. Methodology for defining a significant impact on French health insurance costs and selection of benchmarks for interpreting results.

PubMed

Dervaux, Benoît; Baseilhac, Eric; Fagon, Jean-Yves; Biot, Claire; Blachier, Corinne; Braun, Eric; Debroucker, Frédérique; Detournay, Bruno; Ferretti, Carine; Granger, Muriel; Jouan-Flahault, Chrystel; Lussier, Marie-Dominique; Meyer, Arlette; Muller, Sophie; Pigeon, Martine; De Sahb, Rima; Sannié, Thomas; Sapède, Claudine; Vray, Muriel

2014-01-01

Decree No. 2012-1116 of 2 October 2012 on medico-economic assignments of the French National Authority for Health (Haute autorité de santé, HAS) significantly alters the conditions for accessing the health products market in France. This paper presents a theoretical framework for interpreting the results of the economic evaluation of health technologies and summarises the facts available in France for developing benchmarks that will be used to interpret incremental cost-effectiveness ratios. This literature review shows that it is difficult to determine a threshold value but it is also difficult to interpret then incremental cost effectiveness ratio (ICER) results without a threshold value. In this context, round table participants favour a pragmatic approach based on "benchmarks" as opposed to a threshold value, based on an interpretative and normative perspective, i.e. benchmarks that can change over time based on feedback. © 2014 Société Française de Pharmacologie et de Thérapeutique.

Effects of a coastal power plant thermal discharge on phytoplankton community structure in Zhanjiang Bay, China.

PubMed

Li, Xue-Ying; Li, Bin; Sun, Xing-Li

2014-04-15

The effects of a thermal discharge from a coastal power plant on phytoplankton were determined in Zhanjiang Bay. Monthly cruises were undertaken at four tide times during April-October 2011. There were significant differences for dominant species among seven sampling months and four sampling tides. Species diversity (H') and Evenness showed a distinct increasing gradient from the heated water source to the control zone and fluctuated during four tides with no visible patterns. Species richness, cell count and Chl a at mixed and control zones were significantly higher than heated zones, and showed tidal changes with no obvious patterns. The threshold temperature of phytoplankton species can be regarded as that of phytoplankton community at ebb slack. The average threshold temperature over phytoplankton species, cell count and Chl a, and the threshold temperature of cell count can be regarded as that of phytoplankton community at flood slack during spring and neap respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Adaptive threshold control for auto-rate fallback algorithm in IEEE 802.11 multi-rate WLANs

NASA Astrophysics Data System (ADS)

Wu, Qilin; Lu, Yang; Zhu, Xiaolin; Ge, Fangzhen

2012-03-01

The IEEE 802.11 standard supports multiple rates for data transmission in the physical layer. Nowadays, to improve network performance, a rate adaptation scheme called auto-rate fallback (ARF) is widely adopted in practice. However, ARF scheme suffers performance degradation in multiple contending nodes environments. In this article, we propose a novel rate adaptation scheme called ARF with adaptive threshold control. In multiple contending nodes environment, the proposed scheme can effectively mitigate the frame collision effect on rate adaptation decision by adaptively adjusting rate-up and rate-down threshold according to the current collision level. Simulation results show that the proposed scheme can achieve significantly higher throughput than the other existing rate adaptation schemes. Furthermore, the simulation results also demonstrate that the proposed scheme can effectively respond to the varying channel condition.

A two-dimensional analytical modeling for channel potential and threshold voltage of short channel triple material symmetrical gate Stack (TMGS) DG-MOSFET

NASA Astrophysics Data System (ADS)

Tripathi, Shweta

2016-10-01

In the present work, a two-dimensional (2D) analytical framework of triple material symmetrical gate stack (TMGS) DG-MOSFET is presented in order to subdue the short channel effects. A lightly doped channel along with triple material gate having different work functions and symmetrical gate stack structure, showcases substantial betterment in quashing short channel effects to a good extent. The device functioning amends in terms of improved exemption to threshold voltage roll-off, thereby suppressing the short channel effects. The encroachments of respective device arguments on the threshold voltage of the proposed structure are examined in detail. The significant outcomes are compared with the numerical simulation data obtained by using 2D ATLAS™ device simulator to affirm and formalize the proposed device structure.

The effects of lipoic acid and methylprednisolone on nerve healing in rats with facial paralysis.

PubMed

Tekdemir, Emrah; Tatlipinar, Arzu; Özbeyli, Dilek; Tekdemir, Özge; Kınal, Emrah

2018-06-01

To investigate the effects of lipoic acid and methylprednisolone on nerve healing in rats with traumatic facial paralysis. The rats were randomly divided into four groups, with six rats in the control group and eight each in the remaining three groups. The buccal branch of the facial nerve in all groups except the control group was traumatized by a vascular clamp for 40 minutes. Group 1 was given lipoic acid (LA), Group 2 was given methylprednisolone (MP), and Group 3 was given lipoic acid and methylprednisolone (LA + MP) for one week. Nerve stimulus thresholds were measured before trauma, after trauma and at the end of the one week treatment period. When the groups were compared with each other, post-treatment threshold levels of LA + MP were significantly lower than LA. Although post-treatment threshold levels of LA and MP were still higher than the control group, there was no significant difference between LA + MP and control values (p > .05). Lipoic acid has a positive effect on nerve healing and can enhance the effect of methylprednisolone treatment. It is a good alternative in cases where methylprednisolone cannot be used.

Differences in taste detection thresholds between normal-weight and obese young adults.

PubMed

Park, Dong Choon; Yeo, Joon Hyung; Ryu, In Yong; Kim, Sang Hoon; Jung, Junyang; Yeo, Seung Geun

2015-05-01

Compared with normal-weight individuals, obese young adults exhibited a significantly higher taste threshold for salty taste. Smoking also affected taste functions in this population. The aim of this study was to investigate the differences in taste detection thresholds between normal-weight and obese young adults. Taste threshold was measured using electrogustometry (EGM) and chemically with sucrose, NaCl, citric acid, and quinine hydrochloride in 41 volunteers in their twenties, 23 with body mass index (BMI) <23 kg/m(2) (normal-weight group) and 18 with BMI >25 kg/m(2) (obese group). BMI was significantly higher in the obese than in the normal-weight group (p < 0.05). The obese group exhibited significantly higher EGM thresholds than the normal-weight group on the right (p < 0.05) and left (p < 0.05) posterior tongue. In chemical taste tests, the obese group had higher thresholds for sweet, salty, sour, and bitter tastes than the normal-weight group, although the difference in threshold was significant only for salty taste (p < 0.05). Smoking had an impact on taste threshold, with smokers having higher thresholds than non-smokers, with significantly higher EGM thresholds on the right anterior and posterior and the left anterior tongue (p < 0.05 each).

25-Hydroxyvitamin D Threshold for the Effects of Vitamin D Supplements on Bone Density Secondary Analysis of a Randomized Controlled Trial.

PubMed

Macdonald, Helen M; Reid, Ian R; Gamble, Gregory D; Fraser, William D; Tang, Jonathan C; Wood, Adrian D

2018-04-17

Most trials of vitamin D supplementation have shown no benefits on bone density (BMD), though severe vitamin D deficiency causes osteomalacia which is associated with profound BMD deficits. Recently, the ViDA-BMD study from New Zealand demonstrated a threshold of baseline 25-hydroxyvitamin D (30 nmol/L) below which vitamin D supplementation did benefit BMD. We have now re-examined data from a similar trial in Aberdeen to determine whether a baseline 25-hydroxyvitamin D threshold of 30 nmol/L is also observed in that database. The Aberdeen study recruited 305 postmenopausal women in late winter and randomized them to receive placebo, vitamin D 400 IU/day or vitamin D 1000 IU/day over one year. As previously reported, BMD loss at the hip was reduced by vitamin D 1000 IU/day only, and there was no significant treatment effect of either dose at the lumbar spine. In the present analysis, when the trial participants were grouped according to whether their baseline 25-hydroxyvitamin D was ≤30 nmol/L or above this threshold, significant treatment effects were apparent at both the spine and hip in those with baseline 25-hydroxyvitamin D ≤30 nmol/L, but no significant effects were apparent in those with baseline 25-hydroxyvitamin D above this level. There was evidence of a similar threshold for effects on parathyroid hormone, but no groups showed changes in bone turnover markers during the study. It is concluded that vitamin D supplements only increase bone density in adults with nadir 25-hydroxyvitamin D ≤30 nmol/L. This moves us further towards a trial-based definition of vitamin D deficiency in adults with adequate calcium intakes, and suggests that supplement use should be targeted accordingly. Future trials of vitamin D supplementation should focus on individuals with 25-hydroxyvitamin D concentrations in this range. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The Effect of Systemic Steroid on Hearing Preservation After Cochlear Implantation via Round Window Approach: A Guinea Pig Model.

PubMed

Chang, Mun Young; Rah, Yoon Chan; Choi, Jun Jae; Woo, Shin Wook; Hwang, Yu-Jung; Eastwood, Hayden; O'Leary, Stephen J; Lee, Jun Ho

2017-08-01

When administered perioperatively, systemic dexamethasone will reduce the hearing loss associated with cochlear implantation (CI) performed via the round window approach. The benefits of electroacoustic stimulation have led to interest in pharmacological interventions to preserve hearing after CI. Thirty guinea pigs were randomly divided into three experimental groups: a control group; a 3-day infusion group; and a 7-day infusion group. Dexamethasone was delivered via a mini-osmotic pump for either 3 or 7 days after CI via the round window. Pure tone-evoked auditory brainstem response (ABR) thresholds were monitored for a period of 12 weeks after CI. The cochleae were then collected for histology. At 4 and 12 weeks after CI, ABR threshold shifts were significantly reduced in both 7-day and 3-day infusion groups compared with the control group. Furthermore, the 7-day infusion group has significantly reduced ABR threshold shifts compared with the 3-day infusion group. The total tissue response, including fibrosis and ossification, was significantly reduced in the 7-day infusion group compared with the control group. On multiple regression the extent of fibrosis predicted hearing loss across most frequencies, while hair cell counts predicted ABR thresholds at 32 kHz. Hearing protection after systemic administration of steroids is more effective when continued for at least a week after CI. Similarly, this treatment approach was more effective in reducing the fibrosis that encapsulates the CI electrode. Reduced fibrosis seemed to be the most likely explanation for the hearing protection.

Vibrotactile perception thresholds at the sole of the foot: effects of contact force and probe indentation.

PubMed

Gu, Cheng; Griffin, Michael J

2012-05-01

When using vibrotactile thresholds to investigate neuropathy in the fingers, the indentation of a vibrating probe, and the force applied to a static surround around a vibrating probe, affect thresholds. This study was designed to investigate the effects on vibrotactile perception thresholds at the sole of the foot of probe indentation (i.e. height of a vibrating probe relative to a static surround) and the force applied to the static surround. Thresholds at 20 Hz (expected to be mediated by the NP I channel) and at 160 Hz (expected to be mediated by the Pacinian channel) were obtained at the hallux (i.e. greater toe) and the ball of the foot on 14 healthy subjects. In one condition, the height of the vibrating probe was varied to 0, 1, 2, 3, and 4 mm above a static surround with 4-N force applied to the surround. In a second condition, the force applied to the surround was varied to 1, 2, 3, 4, 5, and 6 N while using a probe height of 1mm. Thresholds at 20 Hz decreased with increasing probe height from 0 to 1 mm but showed no significant variation between 2, 3, and 4mm at either the hallux or the ball of the foot. Thresholds at 160 Hz decreased with increasing probe height from 0 to 4 mm at both the hallux and the ball of the foot. Thresholds at 20 Hz obtained with 1-N surround force were higher than thresholds obtained with 2 N, but there was no significant difference with surround forces from 2 to 6 N at either the hallux or the ball of the foot. Thresholds at 160 Hz were unaffected by variations in surround force at the ball of the foot but tended to decrease with increasing force at the hallux. It is concluded that a vibrating probe flush with a static surround, and a surround force in the range 2-4 N, are appropriate when measuring vibrotactile thresholds at the hallux and the ball of the foot with a 6-mm diameter contactor and a 2-mm gap to the static surround. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.

Bionanocomposites produced from cassava starch and oil palm mesocarp cellulose nanowhiskers.

PubMed

Campos, Adriana de; Sena Neto, Alfredo R de; Rodrigues, Vanessa B; Luchesi, Bruno R; Moreira, Francys K V; Correa, Ana Carolina; Mattoso, Luiz H C; Marconcini, José M

2017-11-01

Cassava starch films reinforced with cellulose nanowhiskers from oil palm mesocarp fibers were produced by casting. Nanowhiskers were obtained by sulphuric acid hydrolysis followed by microfluidization and incorporated in starch films at various loadings (1-10wt%). Morphological and mechanical characterizations showed that the reinforcing effect of oil palm cellulose nanowhiskers was significant at loadings of up to 6wt%, which was determined to be the nanowhiskers percolation threshold. Above this content, formation of agglomerates became more significant, causing a decrease in mechanical properties of starch bionanocomposites. Below percolation threshold, such as 2wt%, elongation at break increased by 70%, showing an effective reinforcing effect. Dynamic mechanical analyses revealed filler/matrix interactions through hydrogen bonding in bionanocomposites. Copyright © 2017 Elsevier Ltd. All rights reserved.

An animal model for the analysis of cochlear blood flow [corrected] disturbance and hearing threshold in vivo.

PubMed

Canis, Martin; Arpornchayanon, Warangkana; Messmer, Catalina; Suckfuell, Markus; Olzowy, Bernhard; Strieth, Sebastian

2010-02-01

Impairment of cochlear blood flow (CBF) is considered to be important in inner ear pathology. However, direct measurement of CBF is difficult and has not been investigated in combination with hearing function. Six guinea pigs were used to show feasibility of an animal model for the analysis of cochlear microcirculation by intravital microscopy in combination with investigation of the hearing threshold by brainstem response audiometry (ABR). By the application of sodium nitroprusside (SNP), CBF was increased over 30 min. Reproducibility of measurements was shown by retest measurements. Mean baseline velocity of CBF was 109 +/- 19 mum/s. Vessel diameters had a mean value of 9.4 +/- 2.7 mum. Mean hearing threshold was 19 +/- 6 dB. In response to SNP, CBF velocity increased significantly to 161 +/- 26 mum/s. Mean arterial pressure decreased significantly to 36 +/- 11 mmHg. After the end of the application, CBF velocity recovered to a minimum of 123 +/- 17 microm/s. Within the retest, CBF velocity significantly increased to a maximum of 160 +/- 31 microm/s. Second recovery of CBF velocity was 125 +/- 14 mum/s. Within the second retest, CBF increased significantly to 157 +/- 25 microm/s. ABR thresholds did not change significantly. The increase in blood flow velocity occurred in spite of substantial hypotension as induced by a vasodilator. This may explain the fact that ABR threshold remained unchanged reflecting a maintained blood supply in this part of the brain. This technique can be used to evaluate effects of treatments aimed at cochlear microcirculation in inner ear pathologies.

CO2 laser stapedotomy safety: influence of laser energy and time on bone-conduction hearing levels.

PubMed

Schönfeld, Uwe; Weiming, Hu; Hofmann, Veit M; Jovanovic, Sergije; Albers, Andreas E

2017-12-01

Total laser energy in CO 2 stapedotomy depends on the laser settings and the amount of applications. It is unclear if the amount of total laser energy affects bone-conduction hearing thresholds and if possible effects are temporary or permanent. Alterations of bone-conduction hearing thresholds after single or multiple-shot CO 2 laser stapedotomy were analyzed between 1 and 3 weeks and 1.5-6 months after primary (n = 501) or revision surgeries (n = 153) and correlated to time, laser energy, frequency, surgical technique, and pathology encountered in revision stapedotomy. In both time periods, most patients showed a lower bone-conduction threshold in the four-tone puretone average (PTA) at frequencies of 0.5, 1, 2, and 3 kHz that further improved over time. Between 1 and 3 weeks, the improvement was significant in subgroups with cumulative energies lower 1 J and successful one-shot technique or in revisions without laser application. The remaining subgroups with higher total energies showed significant improvements between 1.5 and 6 months. At 4 and 8 kHz, significant improvements were found during 1.5-6 months after primary and revision surgery independent of the used energy. Repeated CO 2 laser applications showed no impairment in bone-conduction thresholds and can thus be considered as safe. In most patients, significant, yet unexplained, improvements in bone-conduction hearing thresholds were noticed in a time- and energy-related pattern.

Impact of the round window membrane accessibility on hearing preservation in adult cochlear implantation.

PubMed

Mirsalehi, Marjan; Mohebbi, Saleh; Ghajarzadeh, Mahsa; Lenarz, Thomas; Majdani, Omid

2017-08-01

This study was conducted to evaluate the effect of the round window membrane accessibility on the residual hearing after cochlear implantation surgery in adults. Moreover, the effects of the other demographics and intra-operative factors on the residual hearing loss have been evaluated. The hearing preservation cochlear implantation surgery was performed on 64 adults with residual hearing thresholds ≤80 dB at 250 and 500 Hz, who had referred to our tertiary academic center. All the patients underwent a standardized surgical approach with the same straight electrode inserted through the round window membrane. The hearing thresholds at 250, 500, and 1000 Hz were compared in pre-operative and 1 month postoperative pure-tone audiograms. The average hearing threshold shifts at these frequencies was used to evaluate the hearing preservation. The effects of the round window accessibility and other factors (including gender, age, side of the surgery, necessity of anterior-inferior drilling of the round window margin and average insertion speed) on hearing threshold shifts were analyzed. The mean low-frequency hearing threshold shift was found to be 17.5 dB for all the patients. The hearing preservation goal (threshold shifts ≤30 dB) was achieved in 58 patients. Among the evaluated parameters, only accessibility of the round window membrane could change the hearing threshold shifts significantly (p = 0.026), and was a predictor for the hearing loss (B coefficient = 7.5, p = 0.006). Incomplete accessibility of the round window membrane may be a predictor for increased hearing threshold shifts in short-term evaluations after cochlear implantation.

Assessment of Maximum Aerobic Capacity and Anaerobic Threshold of Elite Ballet Dancers.

PubMed

Wyon, Matthew A; Allen, Nick; Cloak, Ross; Beck, Sarah; Davies, Paul; Clarke, Frances

2016-09-01

An athlete's cardiorespiratory profile, maximal aerobic capacity, and anaerobic threshold is affected by training regimen and competition demands. The present study aimed to ascertain whether there are company rank differences in maximal aerobic capacity and anaerobic threshold in elite classical ballet dancers. Seventy-four volunteers (M 34, F 40) were recruited from two full-time professional classical ballet companies. All participants completed a continuous incremental treadmill protocol with a 1-km/hr speed increase at the end of each 1-min stage until termination criteria had been achieved (e.g., voluntary cessation, respiratory exchange ratio <1.15, HR ±5 bpm of estimated HRmax). Peak VO2 (5-breathe smooth) was recorded and anaerobic threshold calculated using ventilatory curve and ventilatory equivalents methods. Statistical analysis reported between-subject effects for gender (F1,67=35.18, p<0.001) and rank (F1,67=8.67, p<0.001); post hoc tests reported soloists (39.5±5.15 mL/kg/min) as having significantly lower VO2 peak than artists (45.9±5.75 mL/kg/min, p<0.001) and principal dancers (48.07±3.24 mL/kg/min, p<0.001). Significant differences in anaerobic threshold were reported for age (F1,67=7.68, p=0.008) and rank (F1,67=3.56, p=0.034); post hoc tests reported artists (75.8±5.45%) having significantly lower anaerobic threshold than soloists (80.9±5.71, p<0.01) and principals (84.1±4.84%, p<0.001). The observed differences in VO2 peak and anaerobic threshold between the ranks in ballet companies are probably due to the different rehearsal and performance demands.

Comparison of the effects of the alpha-2 agonists detomidine, romifidine and xylazine on nociceptive withdrawal reflex and temporal summation in horses.

PubMed

Rohrbach, Helene; Korpivaara, Toni; Schatzmann, Urs; Spadavecchia, Claudia

2009-07-01

To evaluate and compare the antinociceptive effects of the three alpha-2 agonists, detomidine, romifidine and xylazine at doses considered equipotent for sedation, using the nociceptive withdrawal reflex (NWR) and temporal summation model in standing horses. Prospective, blinded, randomized cross-over study. Ten healthy adult horses weighing 527-645 kg and aged 11-21 years old. Electrical stimulation was applied to the digital nerves to evoke NWR and temporal summation in the left thoracic limb and pelvic limb of each horse. Electromyographic reflex activity was recorded from the common digital extensor and the cranial tibial muscles. After baseline measurements a single bolus dose of detomidine, 0.02 mg kg(-1), romifidine 0.08 mg kg(-1), or xylazine, 1 mg kg(-1), was administered intravenously (IV). Determinations of NWR and temporal summation thresholds were repeated at 10, 20, 30, 40, 60, 70, 90, 100, 120 and 130 minutes after test-drug administration alternating the thoracic limb and the pelvic limb. Depth of sedation was assessed before measurements at each time point. Behavioural reaction was observed and recorded following each stimulation. The administration of detomidine, romifidine and xylazine significantly increased the current intensities necessary to evoke NWR and temporal summation in thoracic limbs and pelvic limbs of all horses compared with baseline. Xylazine increased NWR thresholds over baseline values for 60 minutes, while detomidine and romifidine increased NWR thresholds over baseline for 100 and 120 minutes, respectively. Temporal summation thresholds were significantly increased for 40, 70 and 130 minutes after xylazine, detomidine and romifidine, respectively. Detomidine, romifidine and xylazine, administered IV at doses considered equipotent for sedation, significantly increased NWR and temporal summation thresholds, used as a measure of antinociceptive activity. The extent of maximal increase of NWR and temporal summation thresholds was comparable, while the duration of action was drug-specific.

Short-term effects of meteorological factors on hand, foot and mouth disease among children in Shenzhen, China: Non-linearity, threshold and interaction.

PubMed

Zhang, Zhen; Xie, Xu; Chen, Xiliang; Li, Yuan; Lu, Yan; Mei, Shujiang; Liao, Yuxue; Lin, Hualiang

2016-01-01

Various meteorological factors have been associated with hand, foot and mouth disease (HFMD) among children; however, fewer studies have examined the non-linearity and interaction among the meteorological factors. A generalized additive model with a log link allowing Poisson auto-regression and over-dispersion was applied to investigate the short-term effects daily meteorological factors on children HFMD with adjustment of potential confounding factors. We found positive effects of mean temperature and wind speed, the excess relative risk (ERR) was 2.75% (95% CI: 1.98%, 3.53%) for one degree increase in daily mean temperature on lag day 6, and 3.93% (95% CI: 2.16% to 5.73%) for 1m/s increase in wind speed on lag day 3. We found a non-linear effect of relative humidity with thresholds with the low threshold at 45% and high threshold at 85%, within which there was positive effect, the ERR was 1.06% (95% CI: 0.85% to 1.27%) for 1 percent increase in relative humidity on lag day 5. No significant effect was observed for rainfall and sunshine duration. For the interactive effects, we found a weak additive interaction between mean temperature and relative humidity, and slightly antagonistic interaction between mean temperature and wind speed, and between relative humidity and wind speed in the additive models, but the interactions were not statistically significant. This study suggests that mean temperature, relative humidity and wind speed might be risk factors of children HFMD in Shenzhen, and the interaction analysis indicates that these meteorological factors might have played their roles individually. Copyright © 2015 Elsevier B.V. All rights reserved.

Cost-effectiveness of colorectal cancer screening with computed tomography colonography according to a polyp size threshold for polypectomy.

PubMed

Heresbach, Denis; Chauvin, Pauline; Hess-Migliorretti, Aurélie; Riou, Françoise; Grolier, Jacques; Josselin, Jean-Michel

2010-06-01

Computed tomography colonography (CTC) has an acceptable accuracy in detecting colonic lesions, especially for polyps at least 6 mm. The aim of this analysis is to determine the cost-effectiveness of population-based screening for colorectal cancer (CRC) using CTC with a polyp size threshold. The cost-effectiveness ratios of CTC performed at 50, 60 and 70 years old, without (PL strategy) or with (TS strategy) polyp size threshold were compared using a Markov process. Incremental cost-effectiveness ratios (ICER) were calculated per life-years gained (LYG) for a time horizon of 30 years. The ICER of PL and TS strategies were 12 042 and 2765 euro/LYG associated to CRC prevention rates of 37.9 and 36.5%. The ICER of PL and TS strategies dropped to 9687 and 1857 euro/LYG when advanced adenoma (AA) prevalence increased from 6.9 to 8.6% for male participants and 3.8-4.9% for female participants or to 9482 and 2067 euro/LYG when adenoma and AA annual recurrence rates dropped to 3.2 and 0.25%. The ICER for PL and TS strategies decreased to 7947 and 954 euro/LYG or when only two CTC were performed at 50 and 60-years-old. Conversely, the ICER did not significantly change when varying population participation rate or accuracy of CTC. CTC with a 6 mm threshold for polypectomy is associated to a substantial cost reduction without significant loss of efficacy. Cost-effectiveness depends more on the AA prevalence or transition rate to CRC than on CTC accuracy or screening compliance.

Effects of Parenteral Papaverine and Piracetam Administration on Cochlea Following Acoustic Trauma

PubMed Central

Yurtsever Kum, Nurcan; Yilmaz, Yavuz F.; Gurgen, Seren G.; Kum, Rauf O.; Ozcan, Muge; Unal, Adnan

2018-01-01

Introduction: Noise exposure, the main cause of hearing loss in countries with lot of industries, may result both in temporary or permanent hearing loss. The goal of this study was to investigate the effects of parenteral papaverine and piracetam administration following an acoustic trauma on hearing function with histopathologic correlation. Materials and Methods: Eighteen Wistar albino rats exposed to noise for 8 h in a free environment were included. We divided the study population into three groups, and performed daily intraperitoneal injections of papaverine, piracetam, and saline, respectively, throughout the study. We investigated the histopathologic effects of cellular apoptosis on inner hair cells (IHCs) and outer hair cells (OHCs) and compared the distortion product otoacoustic emissions (DPOAEs) thresholds among the groups. Results and Discussion: On the 3rd and 7th days, DPOAE thresholds at 8 kHz were significantly higher both in papaverine and piracetam groups compared with the control group (P = 0.004 for 3rd day, P = 0.016 and P = 0.028 for 7th day, respectively). On the 14th day, piracetam group had significantly higher mean thresholds at 8 kHz (P = 0.029); however, papaverine group had similar mean thresholds compared to the control group (P = 0.200). On the 3rd and 7th days following acoustic trauma, both IHC and OHC loss were significantly lower in both papaverine and piracetam groups. On the 7th day, the mean amount of apoptotic IHCs and OHCs identified using Caspase-3 method were significantly lower in both groups, but the mean amount identified using terminal deoxynucleotidyl transferase dUTP nick end labeling method were similar in both groups compared to the control group. Conclusion: We demonstrated the effects of papaverine and piracetam on the recovery of cochlear damage due to acoustic trauma on experimental animals using histopathologic and electrophysiologic examinations. PMID:29676295

Effects of parenteral papaverine and piracetam administration on cochlea following acoustic trauma.

PubMed

Kum, Nurcan Yurtsever; Yilmaz, Yavuz F; Gurgen, Seren G; Kum, Rauf O; Ozcan, Muge; Unal, Adnan

2018-01-01

Noise exposure, the main cause of hearing loss in countries with lot of industries, may result both in temporary or permanent hearing loss. The goal of this study was to investigate the effects of parenteral papaverine and piracetam administration following an acoustic trauma on hearing function with histopathologic correlation. Eighteen Wistar albino rats exposed to noise for 8 h in a free environment were included. We divided the study population into three groups, and performed daily intraperitoneal injections of papaverine, piracetam, and saline, respectively, throughout the study. We investigated the histopathologic effects of cellular apoptosis on inner hair cells (IHCs) and outer hair cells (OHCs) and compared the distortion product otoacoustic emissions (DPOAEs) thresholds among the groups. On the 3 rd and 7 th days, DPOAE thresholds at 8 kHz were significantly higher both in papaverine and piracetam groups compared with the control group (P = 0.004 for 3 rd day, P = 0.016 and P = 0.028 for 7 th day, respectively). On the 14 th day, piracetam group had significantly higher mean thresholds at 8 kHz (P = 0.029); however, papaverine group had similar mean thresholds compared to the control group (P = 0.200). On the 3 rd and 7 th days following acoustic trauma, both IHC and OHC loss were significantly lower in both papaverine and piracetam groups. On the 7 th day, the mean amount of apoptotic IHCs and OHCs identified using Caspase-3 method were significantly lower in both groups, but the mean amount identified using terminal deoxynucleotidyl transferase dUTP nick end labeling method were similar in both groups compared to the control group. We demonstrated the effects of papaverine and piracetam on the recovery of cochlear damage due to acoustic trauma on experimental animals using histopathologic and electrophysiologic examinations.

Acoustic Reflexes in Normal-Hearing Adults, Typically Developing Children, and Children with Suspected Auditory Processing Disorder: Thresholds, Real-Ear Corrections, and the Role of Static Compliance on Estimates.

PubMed

Saxena, Udit; Allan, Chris; Allen, Prudence

2017-06-01

Previous studies have suggested elevated reflex thresholds in children with auditory processing disorders (APDs). However, some aspects of the child's ear such as ear canal volume and static compliance of the middle ear could possibly affect the measurements of reflex thresholds and thus impact its interpretation. Sound levels used to elicit reflexes in a child's ear may be higher than predicted by calibration in a standard 2-cc coupler, and lower static compliance could make visualization of very small changes in impedance at threshold difficult. For this purpose, it is important to evaluate threshold data with consideration of differences between children and adults. A set of studies were conducted. The first compared reflex thresholds obtained using standard clinical procedures in children with suspected APD to that of typically developing children and adults to test the replicability of previous studies. The second study examined the impact of ear canal volume on estimates of reflex thresholds by applying real-ear corrections. Lastly, the relationship between static compliance and reflex threshold estimates was explored. The research is a set of case-control studies with a repeated measures design. The first study included data from 20 normal-hearing adults, 28 typically developing children, and 66 children suspected of having an APD. The second study included 28 normal-hearing adults and 30 typically developing children. In the first study, crossed and uncrossed reflex thresholds were measured in 5-dB step size. Reflex thresholds were analyzed using repeated measures analysis of variance (RM-ANOVA). In the second study, uncrossed reflex thresholds, real-ear correction, ear canal volume, and static compliance were measured. Reflex thresholds were measured using a 1-dB step size. The effect of real-ear correction and static compliance on reflex threshold was examined using RM-ANOVA and Pearson correlation coefficient, respectively. Study 1 replicated previous studies showing elevated reflex thresholds in many children with suspected APD when compared to data from adults using standard clinical procedures, especially in the crossed condition. The thresholds measured in children with suspected APD tended to be higher than those measured in the typically developing children. There were no significant differences between the typically developing children and adults. However, when real-ear calibrated stimulus levels were used, it was found that children's thresholds were elicited at higher levels than in the adults. A significant relationship between reflex thresholds and static compliance was found in the adult data, showing a trend for higher thresholds in ears with lower static compliance, but no such relationship was found in the data from the children. This study suggests that reflex measures in children should be adjusted for real-ear-to-coupler differences before interpretation. The data in children with suspected APD support previous studies suggesting abnormalities in reflex thresholds. The lack of correlation between threshold and static compliance estimates in children as was observed in the adults may suggest a nonmechanical explanation for age and clinically related effects. American Academy of Audiology

High-frequency (8 to 16 kHz) reference thresholds and intrasubject threshold variability relative to ototoxicity criteria using a Sennheiser HDA 200 earphone.

PubMed

Frank, T

2001-04-01

The first purpose of this study was to determine high-frequency (8 to 16 kHz) thresholds for standardizing reference equivalent threshold sound pressure levels (RETSPLs) for a Sennheiser HDA 200 earphone. The second and perhaps more important purpose of this study was to determine whether repeated high-frequency thresholds using a Sennheiser HDA 200 earphone had a lower intrasubject threshold variability than the ASHA 1994 significant threshold shift criteria for ototoxicity. High-frequency thresholds (8 to 16 kHz) were obtained for 100 (50 male, 50 female) normally hearing (0.25 to 8 kHz) young adults (mean age of 21.2 yr) in four separate test sessions using a Sennheiser HDA 200 earphone. The mean and median high-frequency thresholds were similar for each test session and increased as frequency increased. At each frequency, the high-frequency thresholds were not significantly (p > 0.05) different for gender, test ear, or test session. The median thresholds at each frequency were similar to the 1998 interim ISO RETSPLs; however, large standard deviations and wide threshold distributions indicated very high intersubject threshold variability, especially at 14 and 16 kHz. Threshold repeatability was determined by finding the threshold differences between each possible test session comparison (N = 6). About 98% of all of the threshold differences were within a clinically acceptable range of +/-10 dB from 8 to 14 kHz. The threshold differences between each subject's second, third, and fourth minus their first test session were also found to determine whether intrasubject threshold variability was less than the ASHA 1994 criteria for determining a significant threshold shift due to ototoxicity. The results indicated a false-positive rate of 0% for a threshold shift > or = 20 dB at any frequency and a false-positive rate of 2% for a threshold shift >10 dB at two consecutive frequencies. This study verified that the output of high-frequency audiometers at 0 dB HL using Sennheiser HDA 200 earphones should equal the 1998 interim ISO RETSPLs from 8 to 16 kHz. Further, because the differences between repeated thresholds were well within +/-10 dB and had an extremely low false-positive rate in reference to the ASHA 1994 criteria for a significant threshold shift due to ototoxicity, a Sennheiser HDA 200 earphone can be used for serial monitoring to determine whether significant high-frequency threshold shifts have occurred for patients receiving potentially ototoxic drug therapy.

Kinesio taping and manual pressure release: Short-term effects in subjects with myofasical trigger point.

PubMed

Chao, Yu Wen; Lin, Jiu Jenq; Yang, Jing Lan; Wang, Wendy Tzyy-Jiuan

2016-01-01

Randomized controlled trial. Myofascial pain syndrome is characterized by myofascial trigger points (MTrPs) and fascia tenderness. We investigated the effects of manual pressure release (MPR) alone or in combination with taping (MPR/MKT) in subjects with MTrPs. Fifteen and 16 subjects received MPR and MPR/MKT respectively. Outcomes including Pressure pain threshold, muscle stiffness, mechanomyography were assessed at baseline, post-intervention and 7-days later. Pressure pain threshold improved significantly (d = 1.79, p < 0.005) in both groups. Significant improvement in muscle stiffness in the MPR/MKT group (0.27-0.49 mm) as compared to the MPR group (-0.02-0.23 mm). Mechanomyography amplitude in the MPR/MKT group was significantly higher than that of the MPR group (p < 0.05). MPR and MPR/MKT are effective in reducing pain in these subjects. MPR/MKT has a greater effect on muscle stiffness and contraction amplitude. IV. Copyright © 2016 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Masking overshoot: Effects of ipsilateral, bilateral and contralateral priming

NASA Astrophysics Data System (ADS)

Connington, Maureen Catherine

This study was concerned with masking overshoot, the elevation of the threshold of a brief signal when it is presented at the onset of a masking noise rather than at its temporal center. More specifically, it was concerned with the release from overshoot (i.e., threshold improvement) produced by priming stimuli, presented ipsilaterally, bilaterally and contralaterally at primer- masker gaps of 20, 40 and 80 msec. The more general purpose of the study was to assess the contributions of peripheral and central factors to the overshoot and overshoot-release phenomena. The primers and masking stimuli consisted of white noise bursts of 200 and 400 msec duration, respectively. The probe signal was a 20 msec 4kHz tone. The tone and masker were always presented in one ear. There were, however, 3 modes of primer presentation: ipsilateral, bilateral (identical waveforms to both ears) and contralateral. Three primer-masker gaps of 20, 40 and 80 msec were used. Five normally hearing adults were tested at primer and masker levels of 80 dB HL. Four of the five subjects exhibited significant masking overshoot, when tested without priming. Ipsilateral priming with 20 and 40 msec gaps produced significant masking release from overshoot. Threshold became poorer, however with increasing gap duration and with increasing distance of the perceived primer from the test ear (i.e. ipsilateral priming produced better thresholds than did bilateral priming and bilateral priming produced better thresholds than contralateral priming). There was significant masking enhancement (i.e. threshold was significantly poorer than in the unprimed probe at onset condition) with the contralateral 80 msec primer. The fact that ipsilateral and bilateral primers performed differently does not support the theory that masking overshoot and its release are solely the results of peripheral adaptation. In fact, the group results support the conclusion that masking overshoot is influenced by central factors. However, there were marked inter-subject differences. It seems possible that masking overshoot and its release are influenced by both peripheral adaptation effects and central processes and that the balance between the two is subject-dependent.

Scaling laws for nanoFET sensors

NASA Astrophysics Data System (ADS)

Zhou, Fu-Shan; Wei, Qi-Huo

2008-01-01

The sensitive conductance change of semiconductor nanowires and carbon nanotubes in response to the binding of charged molecules provides a novel sensing modality which is generally denoted as nanoFET sensors. In this paper, we study the scaling laws of nanoplate FET sensors by simplifying nanoplates as random resistor networks with molecular receptors sitting on lattice sites. Nanowire/tube FETs are included as the limiting cases where the device width goes small. Computer simulations show that the field effect strength exerted by the binding molecules has significant impact on the scaling behaviors. When the field effect strength is small, nanoFETs have little size and shape dependence. In contrast, when the field effect strength becomes stronger, there exists a lower detection threshold for charge accumulation FETs and an upper detection threshold for charge depletion FET sensors. At these thresholds, the nanoFET devices undergo a transition between low and large sensitivities. These thresholds may set the detection limits of nanoFET sensors, while they could be eliminated by designing devices with very short source-drain distance and large width.

Effect of gap detection threshold on consistency of speech in children with speech sound disorder.

PubMed

Sayyahi, Fateme; Soleymani, Zahra; Akbari, Mohammad; Bijankhan, Mahmood; Dolatshahi, Behrooz

2017-02-01

The present study examined the relationship between gap detection threshold and speech error consistency in children with speech sound disorder. The participants were children five to six years of age who were categorized into three groups of typical speech, consistent speech disorder (CSD) and inconsistent speech disorder (ISD).The phonetic gap detection threshold test was used for this study, which is a valid test comprised six syllables with inter-stimulus intervals between 20-300ms. The participants were asked to listen to the recorded stimuli three times and indicate whether they heard one or two sounds. There was no significant difference between the typical and CSD groups (p=0.55), but there were significant differences in performance between the ISD and CSD groups and the ISD and typical groups (p=0.00). The ISD group discriminated between speech sounds at a higher threshold. Children with inconsistent speech errors could not distinguish speech sounds during time-limited phonetic discrimination. It is suggested that inconsistency in speech is a representation of inconsistency in auditory perception, which causes by high gap detection threshold. Copyright © 2016 Elsevier Ltd. All rights reserved.

Maximizing capture of gene co-expression relationships through pre-clustering of input expression samples: an Arabidopsis case study.

PubMed

Feltus, F Alex; Ficklin, Stephen P; Gibson, Scott M; Smith, Melissa C

2013-06-05

In genomics, highly relevant gene interaction (co-expression) networks have been constructed by finding significant pair-wise correlations between genes in expression datasets. These networks are then mined to elucidate biological function at the polygenic level. In some cases networks may be constructed from input samples that measure gene expression under a variety of different conditions, such as for different genotypes, environments, disease states and tissues. When large sets of samples are obtained from public repositories it is often unmanageable to associate samples into condition-specific groups, and combining samples from various conditions has a negative effect on network size. A fixed significance threshold is often applied also limiting the size of the final network. Therefore, we propose pre-clustering of input expression samples to approximate condition-specific grouping of samples and individual network construction of each group as a means for dynamic significance thresholding. The net effect is increase sensitivity thus maximizing the total co-expression relationships in the final co-expression network compendium. A total of 86 Arabidopsis thaliana co-expression networks were constructed after k-means partitioning of 7,105 publicly available ATH1 Affymetrix microarray samples. We term each pre-sorted network a Gene Interaction Layer (GIL). Random Matrix Theory (RMT), an un-supervised thresholding method, was used to threshold each of the 86 networks independently, effectively providing a dynamic (non-global) threshold for the network. The overall gene count across all GILs reached 19,588 genes (94.7% measured gene coverage) and 558,022 unique co-expression relationships. In comparison, network construction without pre-sorting of input samples yielded only 3,297 genes (15.9%) and 129,134 relationships. in the global network. Here we show that pre-clustering of microarray samples helps approximate condition-specific networks and allows for dynamic thresholding using un-supervised methods. Because RMT ensures only highly significant interactions are kept, the GIL compendium consists of 558,022 unique high quality A. thaliana co-expression relationships across almost all of the measurable genes on the ATH1 array. For A. thaliana, these networks represent the largest compendium to date of significant gene co-expression relationships, and are a means to explore complex pathway, polygenic, and pleiotropic relationships for this focal model plant. The networks can be explored at sysbio.genome.clemson.edu. Finally, this method is applicable to any large expression profile collection for any organism and is best suited where a knowledge-independent network construction method is desired.

Maximizing capture of gene co-expression relationships through pre-clustering of input expression samples: an Arabidopsis case study

PubMed Central

2013-01-01

Background In genomics, highly relevant gene interaction (co-expression) networks have been constructed by finding significant pair-wise correlations between genes in expression datasets. These networks are then mined to elucidate biological function at the polygenic level. In some cases networks may be constructed from input samples that measure gene expression under a variety of different conditions, such as for different genotypes, environments, disease states and tissues. When large sets of samples are obtained from public repositories it is often unmanageable to associate samples into condition-specific groups, and combining samples from various conditions has a negative effect on network size. A fixed significance threshold is often applied also limiting the size of the final network. Therefore, we propose pre-clustering of input expression samples to approximate condition-specific grouping of samples and individual network construction of each group as a means for dynamic significance thresholding. The net effect is increase sensitivity thus maximizing the total co-expression relationships in the final co-expression network compendium. Results A total of 86 Arabidopsis thaliana co-expression networks were constructed after k-means partitioning of 7,105 publicly available ATH1 Affymetrix microarray samples. We term each pre-sorted network a Gene Interaction Layer (GIL). Random Matrix Theory (RMT), an un-supervised thresholding method, was used to threshold each of the 86 networks independently, effectively providing a dynamic (non-global) threshold for the network. The overall gene count across all GILs reached 19,588 genes (94.7% measured gene coverage) and 558,022 unique co-expression relationships. In comparison, network construction without pre-sorting of input samples yielded only 3,297 genes (15.9%) and 129,134 relationships. in the global network. Conclusions Here we show that pre-clustering of microarray samples helps approximate condition-specific networks and allows for dynamic thresholding using un-supervised methods. Because RMT ensures only highly significant interactions are kept, the GIL compendium consists of 558,022 unique high quality A. thaliana co-expression relationships across almost all of the measurable genes on the ATH1 array. For A. thaliana, these networks represent the largest compendium to date of significant gene co-expression relationships, and are a means to explore complex pathway, polygenic, and pleiotropic relationships for this focal model plant. The networks can be explored at sysbio.genome.clemson.edu. Finally, this method is applicable to any large expression profile collection for any organism and is best suited where a knowledge-independent network construction method is desired. PMID:23738693

Effects of urbanization on benthic macroinvertebrate communities in streams, Anchorage, Alaska

USGS Publications Warehouse

Ourso, Robert T.

2001-01-01

The effect of urbanization on stream macroinvertebrate communities was examined by using data gathered during a 1999 reconnaissance of 14 sites in the Municipality of Anchorage, Alaska. Data collected included macroinvertebrate abundance, water chemistry, and trace elements in bed sediments. Macroinvertebrate relative-abundance data were edited and used in metric and index calculations. Population density was used as a surrogate for urbanization. Cluster analysis (unweighted-paired-grouping method) using arithmetic means of macroinvertebrate presence-absence data showed a well-defined separation between urbanized and nonurbanized sites as well as extracted sites that did not cleanly fall into either category. Water quality in Anchorage generally declined with increasing urbanization (population density). Of 59 variables examined, 31 correlated with urbanization. Local regression analysis extracted 11 variables that showed a significant impairment threshold response and 6 that showed a significant linear response. Significant biological variables for determining the impairment threshold in this study were the Margalef diversity index, Ephemeroptera-Plecoptera-Trichoptera taxa richness, and total taxa richness. Significant thresholds were observed in the water-chemistry variables conductivity, dissolved organic carbon, potassium, and total dissolved solids. Significant thresholds in trace elements in bed sediments included arsenic, iron, manganese, and lead. Results suggest that sites in Anchorage that have ratios of population density to road density greater than 70, storm-drain densities greater than 0.45 miles per square mile, road densities greater than 4 miles per square mile, or population densities greater than 125-150 persons per square mile may require further monitoring to determine if the stream has become impaired. This population density is far less than the 1,000 persons per square mile used by the U.S. Census Bureau to define an urban area.

Non-Markovian Infection Spread Dramatically Alters the Susceptible-Infected-Susceptible Epidemic Threshold in Networks

NASA Astrophysics Data System (ADS)

Van Mieghem, P.; van de Bovenkamp, R.

2013-03-01

Most studies on susceptible-infected-susceptible epidemics in networks implicitly assume Markovian behavior: the time to infect a direct neighbor is exponentially distributed. Much effort so far has been devoted to characterize and precisely compute the epidemic threshold in susceptible-infected-susceptible Markovian epidemics on networks. Here, we report the rather dramatic effect of a nonexponential infection time (while still assuming an exponential curing time) on the epidemic threshold by considering Weibullean infection times with the same mean, but different power exponent α. For three basic classes of graphs, the Erdős-Rényi random graph, scale-free graphs and lattices, the average steady-state fraction of infected nodes is simulated from which the epidemic threshold is deduced. For all graph classes, the epidemic threshold significantly increases with the power exponents α. Hence, real epidemics that violate the exponential or Markovian assumption can behave seriously differently than anticipated based on Markov theory.

Transdiaphragmatic pressure and neural respiratory drive measured during inspiratory muscle training in stable patients with chronic obstructive pulmonary disease.

PubMed

Wu, Weiliang; Zhang, Xianming; Lin, Lin; Ou, Yonger; Li, Xiaoying; Guan, Lili; Guo, Bingpeng; Zhou, Luqian; Chen, Rongchang

2017-01-01

Inspiratory muscle training (IMT) is a rehabilitation therapy for stable patients with COPD. However, its therapeutic effect remains undefined due to the unclear nature of diaphragmatic mobilization during IMT. Diaphragmatic mobilization, represented by transdiaphragmatic pressure (Pdi), and neural respiratory drive, expressed as the corrected root mean square (RMS) of the diaphragmatic electromyogram (EMGdi), both provide vital information to select the proper IMT device and loads in COPD, therefore contributing to the curative effect of IMT. Pdi and RMS of EMGdi (RMSdi%) were measured and compared during inspiratory resistive training and threshold load training in stable patients with COPD. Pdi and neural respiratory drive were measured continuously during inspiratory resistive training and threshold load training in 12 stable patients with COPD (forced expiratory volume in 1 s ± SD was 26.1%±10.2% predicted). Pdi was significantly higher during high-intensity threshold load training (91.46±17.24 cmH 2 O) than during inspiratory resistive training (27.24±6.13 cmH 2 O) in stable patients with COPD, with P <0.01 for each. Significant difference was also found in RMSdi% between high-intensity threshold load training and inspiratory resistive training (69.98%±16.78% vs 17.26%±14.65%, P <0.01). We concluded that threshold load training shows greater mobilization of Pdi and neural respiratory drive than inspiratory resistive training in stable patients with COPD.

Haemoglobin concentration and the risk of death in older adults: differences by race/ethnicity in the NHANES III follow-up.

PubMed

Patel, Kushang V; Longo, Dan L; Ershler, William B; Yu, Binbing; Semba, Richard D; Ferrucci, Luigi; Guralnik, Jack M

2009-05-01

Mildly low haemoglobin concentration is associated with increased mortality in older adults. However, this relationship has not been well characterized in racial/ethnic minorities. Therefore, this study determined the haemoglobin threshold below which risk of death is significantly increased in older non-Hispanic whites, non-Hispanic blacks, and Mexican Americans. Data on 4089 participants of the 1988-94 US National Health and Nutrition Examination Survey who were > or =65 years of age were analyzed with mortality follow-up through December 31, 2000. Mean haemoglobin in non-Hispanic whites (n = 2686) and Mexican Americans (n = 663) was 140 g/l, while in non-Hispanic blacks (n = 740) the mean was 10 g/l lower. A total of 1944 (47.5%) participants died. Among non-Hispanic whites and Mexican Americans, age- and sex-adjusted models showed that the haemoglobin thresholds below which mortality risk was significantly increased were 4 and 2 g/l respectively, above the World Health Organization (WHO) cut-off points for anaemia. In contrast, the threshold for non-Hispanic blacks was 7 g/l below the WHO criteria. Similar threshold effects were observed when analyzing haemoglobin in categories and adjusting for multiple confounders. In conclusion, the haemoglobin threshold below which mortality rises significantly is a full g/dl lower in non-Hispanic blacks than in non-Hispanic whites and Mexican Americans.

The influence of a series of five dry cupping treatments on pain and mechanical thresholds in patients with chronic non-specific neck pain--a randomised controlled pilot study.

PubMed

Lauche, Romy; Cramer, Holger; Choi, Kyung-Eun; Rampp, Thomas; Saha, Felix Joyonto; Dobos, Gustav J; Musial, Frauke

2011-08-15

In this preliminary trial we investigated the effects of dry cupping, an ancient method for treating pain syndromes, on patients with chronic non-specific neck pain. Sensory mechanical thresholds and the participants' self-reported outcome measures of pain and quality of life were evaluated. Fifty patients (50.5 ± 11.9 years) were randomised to a treatment group (TG) or a waiting-list control group (WL). Patients in the TG received a series of 5 cupping treatments over a period of 2 weeks; the control group did not. Self-reported outcome measures before and after the cupping series included the following: Pain at rest (PR) and maximal pain related to movement (PM) on a 100-mm visual analogue scale (VAS), pain diary (PD) data on a 0-10 numeric rating scale (NRS), Neck Disability Index (NDI), and health-related quality of life (SF-36). In addition, the mechanical-detection thresholds (MDT), vibration-detection thresholds (VDT), and pressure-pain thresholds (PPT) were determined at pain-related and control areas. Patients of the TG had significantly less pain after cupping therapy than patients of the WL group (PR: Δ-22.5 mm, p = 0.00002; PM: Δ-17.8 mm, p = 0.01). Pain diaries (PD) revealed that neck pain decreased gradually in the TG patients and that pain reported by the two groups differed significantly after the fifth cupping session (Δ-1.1, p = 0.001). There were also significant differences in the SF-36 subscales for bodily pain (Δ13.8, p = 0.006) and vitality (Δ10.2, p = 0.006). Group differences in PPT were significant at pain-related and control areas (all p < 0.05), but were not significant for MDT or VDT. A series of five dry cupping treatments appeared to be effective in relieving chronic non-specific neck pain. Not only subjective measures improved, but also mechanical pain sensitivity differed significantly between the two groups, suggesting that cupping has an influence on functional pain processing. The trial was registered at clinicaltrials.gov (NCT01289964).

The influence of a series of five dry cupping treatments on pain and mechanical thresholds in patients with chronic non-specific neck pain - a randomised controlled pilot study

PubMed Central

2011-01-01

Background In this preliminary trial we investigated the effects of dry cupping, an ancient method for treating pain syndromes, on patients with chronic non-specific neck pain. Sensory mechanical thresholds and the participants' self-reported outcome measures of pain and quality of life were evaluated. Methods Fifty patients (50.5 ± 11.9 years) were randomised to a treatment group (TG) or a waiting-list control group (WL). Patients in the TG received a series of 5 cupping treatments over a period of 2 weeks; the control group did not. Self-reported outcome measures before and after the cupping series included the following: Pain at rest (PR) and maximal pain related to movement (PM) on a 100-mm visual analogue scale (VAS), pain diary (PD) data on a 0-10 numeric rating scale (NRS), Neck Disability Index (NDI), and health-related quality of life (SF-36). In addition, the mechanical-detection thresholds (MDT), vibration-detection thresholds (VDT), and pressure-pain thresholds (PPT) were determined at pain-related and control areas. Results Patients of the TG had significantly less pain after cupping therapy than patients of the WL group (PR: Δ-22.5 mm, p = 0.00002; PM: Δ-17.8 mm, p = 0.01). Pain diaries (PD) revealed that neck pain decreased gradually in the TG patients and that pain reported by the two groups differed significantly after the fifth cupping session (Δ-1.1, p = 0.001). There were also significant differences in the SF-36 subscales for bodily pain (Δ13.8, p = 0.006) and vitality (Δ10.2, p = 0.006). Group differences in PPT were significant at pain-related and control areas (all p < 0.05), but were not significant for MDT or VDT. Conclusions A series of five dry cupping treatments appeared to be effective in relieving chronic non-specific neck pain. Not only subjective measures improved, but also mechanical pain sensitivity differed significantly between the two groups, suggesting that cupping has an influence on functional pain processing. Trial registration The trial was registered at clinicaltrials.gov (NCT01289964). PMID:21843336

Short-term music-induced hearing loss after sound exposure to discotheque music: the effectiveness of a break in reducing temporary threshold shift.

PubMed

Helleman, Hiske W; Dreschler, Wouter A

2015-02-01

To investigate the effect of a break in music exposure on temporary threshold shifts. A cross-over design where subjects are exposed to dance music for either two hours consecutively, or exposed to two hours of dance music with a one-hour break in between. Outcome measure was the change in hearing threshold, measured in 1-dB steps at different time points after ending the music. Eighteen normal-hearing subjects participated in this study. Changes in pure-tone threshold were observed in both conditions and were similar, regardless of the break. Threshold shifts could be averaged for 1000, 2000, and 4000 Hz. The shift immediately after the ending of the music was 1.7 dB for right ears, and 3.4 dB for left ears. The difference between left and right ears was significant. One hour after the exposure, right ears were recovered to baseline conditions whereas left ears showed a small but clinically irrelevant remaining shift of approximately 1 dB. The advice to use chill-out zones is still valid, because this helps to reduce the duration to the exposure. This study does not provide evidence that a rest period gives an additional reduction of temporary threshold shifts.

Nefopam, a Non-sedative Benzoxazocine Analgesic, Selectively Reduces the Shivering Threshold

PubMed Central

Alfonsi, Pascal; Adam, Frederic; Passard, Andrea; Guignard, Bruno; Sessler, Daniel I.; Chauvin, Marcel

2005-01-01

Background The analgesic nefopam does not compromise ventilation, is minimally sedating, and is effective as a treatment for postoperative shivering. We evaluated the effects of nefopam on the major thermoregulatory responses in humans: sweating, vasoconstriction, and shivering. Methods Nine volunteers were studied on three randomly assigned days: 1) control (Saline), 2) nefopam at a target plasma concentration of 35 ng/ml (Small Dose), and 3) nefopam at a target concentration of 70 ng/ml (Large Dose, ≈20 mg total). Each day, skin and core temperatures were increased to provoke sweating and then reduced to elicit peripheral vasoconstriction and shivering. We determined the thresholds (triggering core temperature at a designated skin temperature of 34°C) by mathematically compensating for changes in skin temperature using the established linear cutaneous contributions to control of each response. Results Nefopam did not significantly modify the slopes for sweating (0.0 ± 4.9°C·μg−1·ml; r2 = 0.73 ± 0.32) or vasoconstriction (−3.6 ± 5.0°C·μg−1·ml; r2=−0.47± 0.41). In contrast, nefopam significantly reduced the slope of shivering (−16.8 ± 9.3°C·μg−1·ml; r2 = 0.92 ± 0.06). Large-Dose nefopam thus reduced the shivering threshold by 0.9 ± 0.4°C (P<0.001) without any discernable effect on the sweating or vasoconstriction thresholds. Conclusions Most drugs with thermoregulatory actions — including anesthetics, sedatives, and opioids — synchronously reduce the vasoconstriction and shivering thresholds. Nefopam however reduced only the shivering threshold. This pattern has not previously been reported for a centrally acting drug. That pharmacologic modulation of vasoconstriction and shivering can be separated is of clinical and physiologic interest. PMID:14695722

Gap Detection and Temporal Modulation Transfer Function as Behavioral Estimates of Auditory Temporal Acuity Using Band-Limited Stimuli in Young and Older Adults

PubMed Central

Shen, Yi

2015-01-01

Purpose Gap detection and the temporal modulation transfer function (TMTF) are 2 common methods to obtain behavioral estimates of auditory temporal acuity. However, the agreement between the 2 measures is not clear. This study compares results from these 2 methods and their dependencies on listener age and hearing status. Method Gap detection thresholds and the parameters that describe the TMTF (sensitivity and cutoff frequency) were estimated for young and older listeners who were naive to the experimental tasks. Stimuli were 800-Hz-wide noises with upper frequency limits of 2400 Hz, presented at 85 dB SPL. A 2-track procedure (Shen & Richards, 2013) was used for the efficient estimation of the TMTF. Results No significant correlation was found between gap detection threshold and the sensitivity or the cutoff frequency of the TMTF. No significant effect of age and hearing loss on either the gap detection threshold or the TMTF cutoff frequency was found, while the TMTF sensitivity improved with increasing hearing threshold and worsened with increasing age. Conclusion Estimates of temporal acuity using gap detection and TMTF paradigms do not seem to provide a consistent description of the effects of listener age and hearing status on temporal envelope processing. PMID:25087722

Complex Variation in Measures of General Intelligence and Cognitive Change

PubMed Central

Rowe, Suzanne J.; Rowlatt, Amy; Davies, Gail; Harris, Sarah E.; Porteous, David J.; Liewald, David C.; McNeill, Geraldine; Starr, John M.

2013-01-01

Combining information from multiple SNPs may capture a greater amount of genetic variation than from the sum of individual SNP effects and help identifying missing heritability. Regions may capture variation from multiple common variants of small effect, multiple rare variants or a combination of both. We describe regional heritability mapping of human cognition. Measures of crystallised (gc) and fluid intelligence (gf) in late adulthood (64–79 years) were available for 1806 individuals genotyped for 549,692 autosomal single nucleotide polymorphisms (SNPs). The same individuals were tested at age 11, enabling us the rare opportunity to measure cognitive change across most of their lifespan. 547,750 SNPs ranked by position are divided into 10, 908 overlapping regions of 101 SNPs to estimate the genetic variance each region explains, an approach that resembles classical linkage methods. We also estimate the genetic variation explained by individual autosomes and by SNPs within genes. Empirical significance thresholds are estimated separately for each trait from whole genome scans of 500 permutated data sets. The 5% significance threshold for the likelihood ratio test of a single region ranged from 17–17.5 for the three traits. This is the equivalent to nominal significance under the expectation of a chi-squared distribution (between 1df and 0) of P<1.44×10−5. These thresholds indicate that the distribution of the likelihood ratio test from this type of variance component analysis should be estimated empirically. Furthermore, we show that estimates of variation explained by these regions can be grossly overestimated. After applying permutation thresholds, a region for gf on chromosome 5 spanning the PRRC1 gene is significant at a genome-wide 10% empirical threshold. Analysis of gene methylation on the temporal cortex provides support for the association of PRRC1 and fluid intelligence (P = 0.004), and provides a prime candidate gene for high throughput sequencing of these uniquely informative cohorts. PMID:24349040

Effect of backpack shoulder straps length on cervical posture and upper trapezius pressure pain threshold

PubMed Central

Abdelraouf, Osama Ragaa; Hamada, Hamada Ahmed; Selim, Ali; Shendy, Wael; Zakaria, Hoda

2016-01-01

[Purpose] This study was performed to investigate the effect of the length of backpack shoulder straps on upper trapezius muscle pain threshold and craniovertebral angle. [Subjects and Methods] There were 25 participants, with ages from 15 to 23 years old. Upper trapezius pain threshold and craniovertebral angle were measured for all subjects without the backpack then re-measured after walking on a treadmill for 15 min under 2 conditions: 1) wearing a backpack with short straps; and 2) wearing a backpack with long straps. [Results] there was a significant reduction in upper trapezius pain threshold and craniovertebral angle while carrying a backpack with long shoulder straps, compared to use of a backpack with short shoulder straps or no backpack. [Conclusion] A backpack with short straps is less harmful than a backpack with long straps. This result should be considered in ergonomic design of backpacks to reduce the incidence of various physiological and biomechanical disorders. PMID:27799665

Intense cold and mortality in Castile-La Mancha (Spain): study of mortality trigger thresholds from 1975 to 2003

NASA Astrophysics Data System (ADS)

Miron, Isidro J.; Montero, Juan Carlos; Criado-Alvarez, Juan José; Linares, Cristina; Díaz, Julio

2012-01-01

Studies on temperature-mortality time trends especially address heat, so that any contribution on the subject of cold is necessarily of interest. This study describes the modification of the lagged effects of cold on mortality in Castile-La Mancha from 1975 to 2003, with the novelty of also approaching this aspect in terms of mortality trigger thresholds. Cross-correlation functions (CCFs) were thus established with 15 lags, after application of ARIMA models to the mortality data and minimum daily temperatures (from November to March), and the results for the periods 1975-1984, 1985-1994 and 1995-2003 were then compared. In addition, daily mortality residuals for the periods 1975-1989 and 1990-2003 were related to minimum temperatures grouped in 2°C intervals, with a cold threshold temperature being obtained in cases where such residuals increased significantly ( p < 0.05) with respect to the mean for the study period. A cold-related mortality trigger threshold of -3°C was obtained for Ciudad Real for the period 1990-2003. The significant number of lags ( p < 0.05) in the CCFs declined every 10 years in Toledo (5-2-0), Cuenca (4-2-0), Albacete (4-3-0) and Ciudad Real (3-2-1). This meant that, while the trend in cold-related mortality trigger thresholds in the region could not be ascertained, it was possible to establish a reduction in the lagged effects of cold on mortality, attributable to the improvement in socio-economic conditions over the study period. Evidence was shown of the effects of cold on mortality, a finding that renders the adoption of preventive measures advisable in any case where intense cold is forecast.

Determination of optimum threshold values for EMG time domain features; a multi-dataset investigation.

PubMed

Kamavuako, Ernest Nlandu; Scheme, Erik Justin; Englehart, Kevin Brian

2016-08-01

For over two decades, Hudgins' set of time domain features have extensively been applied for classification of hand motions. The calculation of slope sign change and zero crossing features uses a threshold to attenuate the effect of background noise. However, there is no consensus on the optimum threshold value. In this study, we investigate for the first time the effect of threshold selection on the feature space and classification accuracy using multiple datasets. In the first part, four datasets were used, and classification error (CE), separability index, scatter matrix separability criterion, and cardinality of the features were used as performance measures. In the second part, data from eight classes were collected during two separate days with two days in between from eight able-bodied subjects. The threshold for each feature was computed as a factor (R = 0:0.01:4) times the average root mean square of data during rest. For each day, we quantified CE for R = 0 (CEr0) and minimum error (CEbest). Moreover, a cross day threshold validation was applied where, for example, CE of day two (CEodt) is computed based on optimum threshold from day one and vice versa. Finally, we quantified the effect of the threshold when using training data from one day and test data of the other. All performance metrics generally degraded with increasing threshold values. On average, CEbest (5.26 ± 2.42%) was significantly better than CEr0 (7.51 ± 2.41%, P = 0.018), and CEodt (7.50 ± 2.50%, P = 0.021). During the two-fold validation between days, CEbest performed similar to CEr0. Interestingly, when using the threshold values optimized per subject from day one and day two respectively, on the cross-days classification, the performance decreased. We have demonstrated that threshold value has a strong impact on the feature space and that an optimum threshold can be quantified. However, this optimum threshold is highly data and subject driven and thus do not generalize well. There is a strong evidence that R = 0 provides a good trade-off between system performance and generalization. These findings are important for practical use of pattern recognition based myoelectric control.

Hypoalgesic effect of a passive accessory mobilisation technique in patients with lateral ankle pain.

PubMed

Yeo, Hwee Koon; Wright, Anthony

2011-08-01

A randomised, double blind, repeated measures study was conducted to investigate the initial effects of an accessory mobilisation technique applied to the ankle joint in 13 patients with a unilateral sub-acute ankle supination injury. Ankle dorsiflexion range of motion, pressure pain threshold, visual analogue scale rating of pain during functional activity and ankle functional scores were assessed before and after application of treatment, manual contact control and no contact control conditions. There were significant improvements in ankle dorsiflexion range of motion (p = 0.000) and pressure pain threshold (p = 0.000) during the treatment condition. However no significant effects were observed for the other measures. These findings demonstrate that mobilisation of the ankle joint can produce an initial hypoalgesic effect and an improvement in ankle dorsiflexion range of motion. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

The anticonvulsant action of AHR-11748 on kindled amygdaloid seizures in rats.

PubMed

Albertson, T E; Walby, W F

1987-03-01

The anticonvulsant effectiveness of AHR-11748 (3-[3-(trifluoromethyl)phenoxy]-1-azetidinecarboxamide) was evaluated in the kindled amygdaloid seizure model in rats. Doses of AHR-11748 that did not cause prestimulation toxicity significantly attenuated elicited afterdischarge durations and the severity of the accompanying behavioral convulsive response in previously kindled rats. AHR-11748 (25-100 mg/kg i.p.) was evaluated at 30 min in previously kindled rats using both threshold (20 microA increments) and suprathreshold (400 microA) paradigms. AHR-11748 (50-100.mg/kg) reduced suprathreshold elicited after discharges and seizure severity. Utilizing a suprathreshold kindling paradigm, the maximum anticonvulsant effectiveness for the 100 mg/kg i.p. dose of AHR-11748 was seen at 180 min. AHR-11748 significantly elevated seizure thresholds only at the 100 mg/kg dose. AHR-11748 (25-100 mg/kg) significantly reduced the severity of threshold elicited seizures. When AHR-11748 (50 and 100 mg/kg i.p.) was administered daily during kindling acquisition, the number of daily trials necessary to complete kindling significantly increased. A reduction in both the duration and the severity of the responses induced by the daily stimulations during the acquisition period was seen with AHR-11748 treatment. This study has demonstrated that AHR-11748 significantly modifies both the acquisition of kindling and the fully kindled amygdaloid seizures at doses that do not cause behavioral toxicity.

Trapping volumetric measurement by multidetector CT in chronic obstructive pulmonary disease: Effect of CT threshold

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xiaohua; Yuan, Huishu; Duan, Jianghui

2013-08-15

Purpose: The purpose of this study was to evaluate the effect of various computed tomography (CT) thresholds on trapping volumetric measurements by multidetector CT in chronic obstructive pulmonary disease (COPD).Methods: Twenty-three COPD patients were scanned with a 64-slice CT scanner in both the inspiratory and expiratory phase. CT thresholds of −950 Hu in inspiration and −950 to −890 Hu in expiration were used, after which trapping volumetric measurements were made using computer software. Trapping volume percentage (Vtrap%) under the different CT thresholds in the expiratory phase and below −950 Hu in the inspiratory phase was compared and correlated with lungmore » function.Results: Mean Vtrap% was similar under −930 Hu in the expiratory phase and below −950 Hu in the inspiratory phase, being 13.18 ± 9.66 and 13.95 ± 6.72 (both lungs), respectively; this difference was not significant (P= 0.240). Vtrap% under −950 Hu in the inspiratory phase and below the −950 to −890 Hu threshold in the expiratory phase was moderately negatively correlated with the ratio of forced expiratory volume in one second to forced vital capacity and the measured value of forced expiratory volume in one second as a percentage of the predicted value.Conclusions: Trapping volumetric measurement with multidetector CT is a promising method for the quantification of COPD. It is important to know the effect of various CT thresholds on trapping volumetric measurements.« less

The effects of electroacupuncture on analgesia and peripheral sensory thresholds in patients with burn scar pain.

PubMed

Cuignet, Olivier; Pirlot, A; Ortiz, S; Rose, T

2015-09-01

The aim of this study is to observe if the effects of electro-acupuncture (EA) on analgesia and peripheral sensory thresholds are transposable from the model of heat pain in volunteers to the clinical setting of burn scar pain. After severe burns, pathological burn scars (PPBS) may occur with excruciating pain that respond poorly to treatment and prevent patients from wearing their pressure garments, thereby leading to unesthetic and function-limiting scars. EA might be of greater benefit in terms of analgesia and functional recovery, should it interrupt this vicious circle by counteracting the peripheral hyperalgesia characterizing PPBS. Therefore we enrolled 32 patients (22 males/10 females) aged of 46±11 years with clinical signs of PPBS and of neuropathic pain despite treatment. The study protocol consisted in 3 weekly 30-min sessions of standardized EA with extra individual needles in accordance to Traditional Chinese Medicine, in addition of previous treatments. We assessed VAS for pain and quantitative sensory testing (QST) twice: one week before and one after protocol. QST measured electrical thresholds for non-nociceptive A-beta fibers, nociceptive A-delta and C fibers in 2 dermatomes, respectively from the PPBS and from the contralateral pain-free areas. Based on heat pain studies, EA consisted in sessions at the extremity points of the main meridian flowing through PPBS (0.300s, 5Hz, sub noxious intensity, 15min) and at the bilateral paravertebral points corresponding to the same metameric level, 15min. VAS reduction of 3 points or below 3 on a 10 points scale was considered clinically relevant. Paired t-test compared thresholds (mean [SD]) and Wilcoxon test compared VAS (median [IQR]) pre and after treatment, significant p<0.05. The reduction of VAS for pain reached statistical but not clinical relevance (6.8 [3] vs. 4.5 [3.6]). This was due to a large subgroup of 14 non-responders whose VAS did not change after treatment (6.6 [2.7] vs. 7.2 [3.8]). That subgroup exhibited significant differences in sensory thresholds when compared to the 18 responders (VAS from 7 [3] to 3 [1]). First, responders' thresholds for A-delta and C fibers in the PPBS area were significantly lower than those in the pain-free area before treatment but corrected after acupuncture (from respectively 60 [30] and 63 [10]% to 91 [11] and 106 [36]%). That might account for a nociceptive hypersensitivity in the PPBS that corrected after treatment. On the contrary, in non-responders nociceptive thresholds were similar in both the PPBS and the pain-free areas before treatment and did not change after EA. However, absolute values for thresholds in the pain-free areas where significantly lower for non-responders than for responders. The fact that non-responders had significant pain scores while presenting with lowered nociceptive thresholds even in the pain-free areas might evoke the possibility of a generalized supra-spinal hyperalgesia. The fact that acupuncture did not correct the pain nor the nociceptive thresholds in this subgroup requires further investigation. We also observed a statistically and clinically relevant reduction in VAS for pruritus for all patients - even those from the subgroup of non-responders to pain - that is worth to be mentioned and requires further studies to be confirmed. This observational study is the first that confirms the effects of acupuncture on analgesia and nociceptive thresholds in the clinical setting of burn pain only for patients presenting with a burn-localized but not a generalized hyperalgesia. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Protective Effect of Ethanol Extracts of Hericium erinaceus on Alloxan-Induced Diabetic Neuropathic Pain in Rats

PubMed Central

Yi, Zhang; Shao-long, Yang; Ai-hong, Wang; Zhi-chun, Sun; Ya-fen, Zhuo; Ye-ting, Xu; Yu-ling, He

2015-01-01

We investigated the effects of Hericium erinaceus (HEE) on alloxan induced diabetic neuropathic pain in laboratory rats. Alloxan induced diabetic rats were administered orally HEE. After 6 weeks of treatments, treatment with HEE 40 mg/kg in diabetic animals showed significant increase in pain threshold and paw withdrawal threshold and significant decrease in serum glucose and urine glucose. We also observed a significant increase in lactate dehydrogenase (LDH), Lipid peroxidation (LPO), glutathione peroxidase (GPx) activity, glutathione reductase (GR) activity, catalase (CAT) activity, Na+K+ATPase activity, and glutathione S transferase (GST) activity along with significant decreased levels of glutathione (GSH) content in diabetic rats. The total antioxidant status (TAOS) in the HEE-treated groups was significantly lower than that in the alloxan-treated group. HEE can offer pain relief in diabetic neuropathic pain. The improvement in diabetic state after HEE treatment along with the antioxidant activity could be the probable way by which it had alleviated diabetic neuropathy. PMID:25960754

Threshold effects in the vegetation response to Holocene climate changes in central Asia

NASA Astrophysics Data System (ADS)

Zhao, Y.

2015-12-01

Understanding the response of ecosystems to past climate is critical for evaluating the impacts of future climate changes. A relatively abrupt vegetation shift in response to the late Holocene gradual climate changes has been well documented for the Sahara-Sahel ecosystem. However, whether such threshold shift is of universal significance remains to be further addressed. Here, we examine the vegetation-climate relationships in central Asia based on four newly recovered Holocene pollen records and a synthesis on previously published pollen data. The results show that the orbital-induced gradual climate trend during the Holocene led to two major abrupt vegetation shifts, and that the timings of these shifts are highly dependent of the local rainfall conditions. Instead, the mid-Holocene vegetation remained rather stable despite of the changing climate. These new findings demonstrate generally significant threshold and truncation effects of climate changes on vegetation, as are strongly supported by surface pollen data and LPJ-GUESS modeling. The results also imply that using pollen data to reconstruct past climate changes is not always straightforward. Our findings have important implication for understanding the potential effects of global warming on dryland ecosystem change.

Deep brain stimulation of the subthalamic nucleus improves temperature sensation in patients with Parkinson's disease.

PubMed

Maruo, Tomoyuki; Saitoh, Youichi; Hosomi, Koichi; Kishima, Haruhiko; Shimokawa, Toshio; Hirata, Masayuki; Goto, Tetsu; Morris, Shayne; Harada, Yu; Yanagisawa, Takufumi; Aly, Mohamed M; Yoshimine, Toshiki

2011-04-01

Patients with Parkinson's disease (PD) reportedly show deficits in sensory processing in addition to motor symptoms. However, little is known about the effects of bilateral deep brain stimulation of the subthalamic nucleus (STN-DBS) on temperature sensation as measured by quantitative sensory testing (QST). This study was designed to quantitatively evaluate the effects of STN-DBS on temperature sensation and pain in PD patients. We conducted a QST study comparing the effects of STN-DBS on cold sense thresholds (CSTs) and warm sense thresholds (WSTs) as well as on cold-induced and heat-induced pain thresholds (CPT and HPT) in 17 PD patients and 14 healthy control subjects. The CSTs and WSTs of patients were significantly smaller during the DBS-on mode when compared with the DBS-off mode (P<.001), whereas the CSTs and WSTs of patients in the DBS-off mode were significantly greater than those of healthy control subjects (P<.02). The CPTs and HPTs in PD patients were significantly larger on the more affected side than on the less affected side (P<.02). Because elevations in thermal sense and pain thresholds of QST are reportedly almost compatible with decreases in sensation, our findings confirm that temperature sensations may be disturbed in PD patients when compared with healthy persons and that STN-DBS can be used to improve temperature sensation in these patients. The mechanisms underlying our findings are not well understood, but improvement in temperature sensation appears to be a sign of modulation of disease-related brain network abnormalities. Copyright © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Childhood Otitis Media: A Cohort Study With 30-Year Follow-Up of Hearing (The HUNT Study).

PubMed

Aarhus, Lisa; Tambs, Kristian; Kvestad, Ellen; Engdahl, Bo

2015-01-01

To study the extent to which otitis media (OM) in childhood is associated with adult hearing thresholds. Furthermore, to study whether the effects of OM on adult hearing thresholds are moderated by age or noise exposure. Population-based cohort study of 32,786 participants who had their hearing tested by pure-tone audiometry in primary school and again at ages ranging from 20 to 56 years. Three thousand sixty-six children were diagnosed with hearing loss; the remaining sample had normal childhood hearing. Compared with participants with normal childhood hearing, those diagnosed with childhood hearing loss caused by otitis media with effusion (n = 1255), chronic suppurative otitis media (CSOM; n = 108), or hearing loss after recurrent acute otitis media (rAOM; n = 613) had significantly increased adult hearing thresholds in the whole frequency range (2 dB/17-20 dB/7-10 dB, respectively). The effects were adjusted for age, sex, and noise exposure. Children diagnosed with hearing loss after rAOM had somewhat improved hearing thresholds as adults. The effects of CSOM and hearing loss after rAOM on adult hearing thresholds were larger in participants tested in middle adulthood (ages 40 to 56 years) than in those tested in young adulthood (ages 20 to 40 years). Eardrum pathology added a marginally increased risk of adult hearing loss (1-3 dB) in children with otitis media with effusion or hearing loss after rAOM. The study could not reveal significant differences in the effect of self-reported noise exposure on adult hearing thresholds between the groups with OM and the group with normal childhood hearing. This cohort study indicates that CSOM and rAOM in childhood are associated with adult hearing loss, underlining the importance of optimal treatment in these conditions. It appears that ears with a subsequent hearing loss after OM in childhood age at a faster rate than those without; however this should be confirmed by studies with several follow-up tests through adulthood.

Reduction of pain thresholds in fibromyalgia after very low-intensity magnetic stimulation: a double-blinded, randomized placebo-controlled clinical trial.

PubMed

Maestú, Ceferino; Blanco, Manuel; Nevado, Angel; Romero, Julia; Rodríguez-Rubio, Patricia; Galindo, Javier; Bautista Lorite, Juan; de las Morenas, Francisco; Fernández-Argüelles, Pedro

2013-01-01

Exposure to electromagnetic fields has been reported to have analgesic and antinociceptive effects in several organisms. To test the effect of very low-intensity transcranial magnetic stimulation on symptoms associated with fibromyalgia syndrome. A double-blinded, placebo-controlled clinical trial was performed in the Sagrado Corazón Hospital, Seville, Spain. Female fibromyalgia patients (22 to 50 years of age) were randomly assigned to either a stimulation group or a sham group. The stimulation group (n=28) was stimulated using 8 Hz pulsed magnetic fields of very low intensity, while the sham group (n=26) underwent the same protocol without stimulation. Pressure pain thresholds before and after stimulation were determined using an algometer during the eight consecutive weekly sessions of the trial. In addition, blood serotonin levels were measured and patients completed questionnaires to monitor symptom evolution. A repeated-measures ANOVA indicated statistically significant improvement in the stimulation group compared with the control group with respect to somatosensory pain thresholds, ability to perform daily activities, perceived chronic pain and sleep quality. While improvement in pain thresholds was apparent after the first stimulation session, improvement in the other three measures occurred after the sixth week. No significant between-group differences were observed in scores of depression, fatigue, severity of headaches or serotonin levels. No adverse side effects were reported in any of the patients. Very low-intensity magnetic stimulation may represent a safe and effective treatment for chronic pain and other symptoms associated with fibromyalgia.

Reduction of pain thresholds in fibromyalgia after very low-intensity magnetic stimulation: A double-blinded, randomized placebo-controlled clinical trial

PubMed Central

Maestú, Ceferino; Blanco, Manuel; Nevado, Angel; Romero, Julia; Rodríguez-Rubio, Patricia; Galindo, Javier; Lorite, Juan Bautista; de las Morenas, Francisco; Fernández-Argüelles, Pedro

2013-01-01

BACKGROUND: Exposure to electromagnetic fields has been reported to have analgesic and antinociceptive effects in several organisms. OBJECTIVE: To test the effect of very low-intensity transcranial magnetic stimulation on symptoms associated with fibromyalgia syndrome. METHODS: A double-blinded, placebo-controlled clinical trial was performed in the Sagrado Corazón Hospital, Seville, Spain. Female fibromyalgia patients (22 to 50 years of age) were randomly assigned to either a stimulation group or a sham group. The stimulation group (n=28) was stimulated using 8 Hz pulsed magnetic fields of very low intensity, while the sham group (n=26) underwent the same protocol without stimulation. Pressure pain thresholds before and after stimulation were determined using an algometer during the eight consecutive weekly sessions of the trial. In addition, blood serotonin levels were measured and patients completed questionnaires to monitor symptom evolution. RESULTS: A repeated-measures ANOVA indicated statistically significant improvement in the stimulation group compared with the control group with respect to somatosensory pain thresholds, ability to perform daily activities, perceived chronic pain and sleep quality. While improvement in pain thresholds was apparent after the first stimulation session, improvement in the other three measures occurred after the sixth week. No significant between-group differences were observed in scores of depression, fatigue, severity of headaches or serotonin levels. No adverse side effects were reported in any of the patients. CONCLUSIONS: Very low-intensity magnetic stimulation may represent a safe and effective treatment for chronic pain and other symptoms associated with fibromyalgia. PMID:24308025

A pilot study of the tolerability and effects of high-definition transcranial direct current stimulation (HD-tDCS) on pain perception.

PubMed

Borckardt, Jeffrey J; Bikson, Marom; Frohman, Heather; Reeves, Scott T; Datta, Abhishek; Bansal, Varun; Madan, Alok; Barth, Kelly; George, Mark S

2012-02-01

Several brain stimulation technologies are beginning to evidence promise as pain treatments. However, traditional versions of 1 specific technique, transcranial direct current stimulation (tDCS), stimulate broad regions of cortex with poor spatial precision. A new tDCS design, called high definition tDCS (HD-tDCS), allows for focal delivery of the charge to discrete regions of the cortex. We sought to preliminarily test the safety and tolerability of the HD-tDCS technique as well as to evaluate whether HD-tDCS over the motor cortex would decrease pain and sensory experience. Twenty-four healthy adult volunteers underwent quantitative sensory testing before and after 20 minutes of real (n = 13) or sham (n = 11) 2 mA HD-tDCS over the motor cortex. No adverse events occurred and no side effects were reported. Real HD-tDCS was associated with significantly decreased heat and cold sensory thresholds, decreased thermal wind-up pain, and a marginal analgesic effect for cold pain thresholds. No significant effects were observed for mechanical pain thresholds or heat pain thresholds. HD-tDCS appears well tolerated, and produced changes in underlying cortex that are associated with changes in pain perception. Future studies are warranted to investigate HD-tDCS in other applications, and to examine further its potential to affect pain perception. This article presents preliminary tolerability and efficacy data for a new focal brain stimulation technique called high definition transcranial direct current stimulation. This technique may have applications in the management of pain. Copyright © 2012. Published by Elsevier Inc.

Antinociceptive effects after oral administration of tramadol hydrochloride in Hispaniolan Amazon parrots (Amazona ventralis).

PubMed

Sanchez-Migallon Guzman, David; Souza, Marcy J; Braun, Jana M; Cox, Sherry K; Keuler, Nicholas S; Paul-Murphy, Joanne R

2012-08-01

To evaluate antinociceptive effects on thermal thresholds after oral administration of tramadol hydrochloride to Hispaniolan Amazon parrots (Amazona ventralis). Animals-15 healthy adult Hispaniolan Amazon parrots. 2 crossover experiments were conducted. In the first experiment, 15 parrots received 3 treatments (tramadol at 2 doses [10 and 20 mg/kg] and a control suspension) administered orally. In the second experiment, 11 parrots received 2 treatments (tramadol hydrochloride [30 mg/kg] and a control suspension) administered orally. Baseline thermal foot withdrawal threshold was measured 1 hour before drug or control suspension administration; thermal foot withdrawal threshold was measured after administration at 0.5, 1.5, 3, and 6 hours (both experiments) and also at 9 hours (second experiment only). For the first experiment, there were no overall effects of treatment, hour, period, or any interactions. For the second experiment, there was an overall effect of treatment, with a significant difference between tramadol hydrochloride and control suspension (mean change from baseline, 2.00° and -0.09°C, respectively). There also was a significant change from baseline for tramadol hydrochloride at 0.5, 1.5, and 6 hours after administration but not at 3 or 9 hours after administration. Tramadol at a dose of 30 mg/kg, PO, induced thermal antinociception in Hispaniolan Amazon parrots. This dose was necessary for induction of significant and sustained analgesic effects, with duration of action up to 6 hours. Further studies with other types of noxious stimulation, dosages, and intervals are needed to fully evaluate the analgesic effects of tramadol hydrochloride in psittacines.

Identification of men with low-risk biopsy-confirmed prostate cancer as candidates for active surveillance.

PubMed

Lin, Daniel W; Crawford, E David; Keane, Thomas; Evans, Brent; Reid, Julia; Rajamani, Saradha; Brown, Krystal; Gutin, Alexander; Tward, Jonathan; Scardino, Peter; Brawer, Michael; Stone, Steven; Cuzick, Jack

2018-06-01

A combined clinical cell-cycle risk (CCR) score that incorporates prognostic molecular and clinical information has been recently developed and validated to improve prostate cancer mortality (PCM) risk stratification over clinical features alone. As clinical features are currently used to select men for active surveillance (AS), we developed and validated a CCR score threshold to improve the identification of men with low-risk disease who are appropriate for AS. The score threshold was selected based on the 90th percentile of CCR scores among men who might typically be considered for AS based on NCCN low/favorable-intermediate risk criteria (CCR = 0.8). The threshold was validated using 10-year PCM in an unselected, conservatively managed cohort and in the subset of the same cohort after excluding men with high-risk features. The clinical effect was evaluated in a contemporary clinical cohort. In the unselected validation cohort, men with CCR scores below the threshold had a predicted mean 10-year PCM of 2.7%, and the threshold significantly dichotomized low- and high-risk disease (P = 1.2 × 10 -5 ). After excluding high-risk men from the validation cohort, men with CCR scores below the threshold had a predicted mean 10-year PCM of 2.3%, and the threshold significantly dichotomized low- and high-risk disease (P = 0.020). There were no prostate cancer-specific deaths in men with CCR scores below the threshold in either analysis. The proportion of men in the clinical testing cohort identified as candidates for AS was substantially higher using the threshold (68.8%) compared to clinicopathologic features alone (42.6%), while mean 10-year predicted PCM risks remained essentially identical (1.9% vs. 2.0%, respectively). The CCR score threshold appropriately dichotomized patients into low- and high-risk groups for 10-year PCM, and may enable more appropriate selection of patients for AS. Copyright © 2018 Elsevier Inc. All rights reserved.

Suppression of threshold voltage variability in MOSFETs by adjustment of ion implantation parameters

NASA Astrophysics Data System (ADS)

Park, Jae Hyun; Chang, Tae-sig; Kim, Minsuk; Woo, Sola; Kim, Sangsig

2018-01-01

In this study, we investigate threshold voltage (VTH) variability of metal-oxide-semiconductor field-effect transistors induced by random dopant fluctuation (RDF). Our simulation work demonstrates not only the influence of the implantation parameters such as its dose, tilt angle, energy, and rotation angle on the RDF-induced VTH variability, but also the solution to reduce the effect of this variability. By adjusting the ion implantation parameters, the 3σ (VTH) is reduced from 43.8 mV to 28.9 mV. This 34% reduction is significant, considering that our technique is very cost effective and facilitates easy fabrication, increasing availability.

Synchrony and exertion during dance independently raise pain threshold and encourage social bonding

PubMed Central

Tarr, Bronwyn; Launay, Jacques; Cohen, Emma; Dunbar, Robin

2015-01-01

Group dancing is a ubiquitous human activity that involves exertive synchronized movement to music. It is hypothesized to play a role in social bonding, potentially via the release of endorphins, which are analgesic and reward-inducing, and have been implicated in primate social bonding. We used a 2 × 2 experimental design to examine effects of exertion and synchrony on bonding. Both demonstrated significant independent positive effects on pain threshold (a proxy for endorphin activation) and in-group bonding. This suggests that dance which involves both exertive and synchronized movement may be an effective group bonding activity. PMID:26510676

THE EFFECT OF TAX PREFERENCES ON HEALTH SPENDING

PubMed Central

Cogan, John F.; Hubbard, R. Glenn; Kessler, Daniel P.

2011-01-01

In this paper, we estimate the effect of the tax preference for health insurance on health care spending using data from the Medical Expenditure Panel Surveys from 1996–2005. We use the fact that Social Security taxes are only levied on earnings below a statutory threshold to identify the impact of the tax preference. Because employer-sponsored health insurance premiums are excluded from Social Security payroll taxes, workers who earn just below the Social Security tax threshold receive a larger tax preference for health insurance than workers who earn just above it. We find a significant effect of the tax preference, consistent with previous research. PMID:22500056

Effect of risk perception on epidemic spreading in temporal networks

NASA Astrophysics Data System (ADS)

Moinet, Antoine; Pastor-Satorras, Romualdo; Barrat, Alain

2018-01-01

Many progresses in the understanding of epidemic spreading models have been obtained thanks to numerous modeling efforts and analytical and numerical studies, considering host populations with very different structures and properties, including complex and temporal interaction networks. Moreover, a number of recent studies have started to go beyond the assumption of an absence of coupling between the spread of a disease and the structure of the contacts on which it unfolds. Models including awareness of the spread have been proposed, to mimic possible precautionary measures taken by individuals that decrease their risk of infection, but have mostly considered static networks. Here, we adapt such a framework to the more realistic case of temporal networks of interactions between individuals. We study the resulting model by analytical and numerical means on both simple models of temporal networks and empirical time-resolved contact data. Analytical results show that the epidemic threshold is not affected by the awareness but that the prevalence can be significantly decreased. Numerical studies on synthetic temporal networks highlight, however, the presence of very strong finite-size effects, resulting in a significant shift of the effective epidemic threshold in the presence of risk awareness. For empirical contact networks, the awareness mechanism leads as well to a shift in the effective threshold and to a strong reduction of the epidemic prevalence.

Investigations of the Cavitation and Damage Thresholds of Histotripsy and Applications in Targeted Tissue Ablation

NASA Astrophysics Data System (ADS)

Vlaisavljevich, Eli

Histotripsy is a noninvasive ultrasound therapy that controls acoustic cavitation to mechanically fractionate soft tissue. This dissertation investigates the physical thresholds to initiate cavitation and produce tissue damage in histotripsy and factors affecting these thresholds in order to develop novel strategies for targeted tissue ablation. In the first part of this dissertation, the effects of tissue properties on histotripsy cavitation thresholds and damage thresholds were investigated. Results demonstrated that the histotripsy shock scattering threshold using multi-cycle pulses increases in stiffer tissues, while the histotripsy intrinsic threshold using single-cycle pulses is independent of tissue stiffness. Further, the intrinsic threshold slightly decreases with lower frequencies and significantly decreases with increasing temperature. The effects of tissue properties on the susceptibility to histotripsy-induced tissue damage were also investigated, demonstrating that stiffer tissues are more resistant to histotripsy. Two strategies were investigated for increasing the effectiveness of histotripsy for the treatment of stiffer tissues, with results showing that thermal preconditioning may be used to alter tissue susceptibility to histotripsy and that lower frequency treatments may increase the efficiency of histotripsy tissue ablation due to enhanced bubble expansion. In the second part of this dissertation, the feasibility of using histotripsy for targeted liver ablation was investigated in an intact in vivo porcine model, with results demonstrating that histotripsy was capable of non-invasively creating precise lesions throughout the entire liver. Additionally, a tissue selective ablation approach was developed, where histotripsy completely fractionated the liver tissue surrounding the major hepatic vessels and gallbladder while being self-limited at the boundaries of these critical structures. Finally, the long-term effects of histotripsy liver ablation were investigated in an intact in vivo rodent model, showing that the liver homogenate resulting from histotripsy-induced tissue fractionation was completely resorbed over the course of 28 days. In the final part of this dissertation, a novel ablation method combining histotripsy with acoustically sensitive nanodroplets was developed for targeted cancer cell ablation, demonstrating the potential of using nanodroplet-mediated histotripsy (NMH) for targeted, multi-focal ablation. Studies demonstrated that lower frequency and higher boiling point perfluorocarbon droplets can improve NMH therapy. The role of positive and negative pressure on cavitation nucleation in NMH was also investigated, showing that NMH cavitation nucleation is caused directly from the peak negative pressure of the incident wave, similar to histotripsy bubbles generated above the intrinsic threshold. Overall, the results of this dissertation provide significant insight into the physical mechanisms underlying histotripsy tissue ablation and will help to guide the future development of histotripsy for clinical applications such as the treatment of liver cancer.

Effects of pulse duration on magnetostimulation thresholds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saritas, Emine U., E-mail: saritas@ee.bilkent.edu.tr; Department of Electrical and Electronics Engineering, Bilkent University, Bilkent, Ankara 06800; National Magnetic Resonance Research Center

Purpose: Medical imaging techniques such as magnetic resonance imaging and magnetic particle imaging (MPI) utilize time-varying magnetic fields that are subject to magnetostimulation limits, which often limit the speed of the imaging process. Various human-subject experiments have studied the amplitude and frequency dependence of these thresholds for gradient or homogeneous magnetic fields. Another contributing factor was shown to be number of cycles in a magnetic pulse, where the thresholds decreased with longer pulses. The latter result was demonstrated on two subjects only, at a single frequency of 1.27 kHz. Hence, whether the observed effect was due to the number ofmore » cycles or due to the pulse duration was not specified. In addition, a gradient-type field was utilized; hence, whether the same phenomenon applies to homogeneous magnetic fields remained unknown. Here, the authors investigate the pulse duration dependence of magnetostimulation limits for a 20-fold range of frequencies using homogeneous magnetic fields, such as the ones used for the drive field in MPI. Methods: Magnetostimulation thresholds were measured in the arms of six healthy subjects (age: 27 ± 5 yr). Each experiment comprised testing the thresholds at eight different pulse durations between 2 and 125 ms at a single frequency, which took approximately 30–40 min/subject. A total of 34 experiments were performed at three different frequencies: 1.2, 5.7, and 25.5 kHz. A solenoid coil providing homogeneous magnetic field was used to induce stimulation, and the field amplitude was measured in real time. A pre-emphasis based pulse shaping method was employed to accurately control the pulse durations. Subjects reported stimulation via a mouse click whenever they felt a twitching/tingling sensation. A sigmoid function was fitted to the subject responses to find the threshold at a specific frequency and duration, and the whole procedure was repeated at all relevant frequencies and pulse durations. Results: The magnetostimulation limits decreased with increasing pulse duration (T{sub pulse}). For T{sub pulse} < 18 ms, the thresholds were significantly higher than at the longest pulse durations (p < 0.01, paired Wilcoxon signed-rank test). The normalized magnetostimulation threshold (B{sub Norm}) vs duration curve at all three frequencies agreed almost identically, indicating that the observed effect is independent of the operating frequency. At the shortest pulse duration (T{sub pulse} ≈ 2 ms), the thresholds were approximately 24% higher than at the asymptotes. The thresholds decreased to within 4% of their asymptotic values for T{sub pulse} > 20 ms. These trends were well characterized (R{sup 2} = 0.78) by a stretched exponential function given by B{sub Norm}=1+αe{sup −(T{sub p}{sub u}{sub l}{sub s}{sub e}/β){sup γ}}, where the fitted parameters were α = 0.44, β = 4.32, and γ = 0.60. Conclusions: This work shows for the first time that the magnetostimulation thresholds decrease with increasing pulse duration, and that this effect is independent of the operating frequency. Normalized threshold vs duration trends are almost identical for a 20-fold range of frequencies: the thresholds are significantly higher at short pulse durations and settle to within 4% of their asymptotic values for durations longer than 20 ms. These results emphasize the importance of matching the human-subject experiments to the imaging conditions of a particular setup. Knowing the dependence of the safety limits to all contributing factors is critical for increasing the time-efficiency of imaging systems that utilize time-varying magnetic fields.« less

Quantum Corrections to the 'Atomistic' MOSFET Simulations

NASA Technical Reports Server (NTRS)

Asenov, Asen; Slavcheva, G.; Kaya, S.; Balasubramaniam, R.

2000-01-01

We have introduced in a simple and efficient manner quantum mechanical corrections in our 3D 'atomistic' MOSFET simulator using the density gradient formalism. We have studied in comparison with classical simulations the effect of the quantum mechanical corrections on the simulation of random dopant induced threshold voltage fluctuations, the effect of the single charge trapping on interface states and the effect of the oxide thickness fluctuations in decanano MOSFETs with ultrathin gate oxides. The introduction of quantum corrections enhances the threshold voltage fluctuations but does not affect significantly the amplitude of the random telegraph noise associated with single carrier trapping. The importance of the quantum corrections for proper simulation of oxide thickness fluctuation effects has also been demonstrated.

Effects of topical benzocaine and lignocaine on upper airway reflex sensitivity.

PubMed

Raphael, J H; Stanley, G D; Langton, J A

1996-02-01

We studied the degree and duration of effect on upper airway reflex sensitivity of oral benzocaine lozenges, nebulised lignocaine and lignocaine sprayed onto the vocal cords under direct vision, using low concentrations of ammonia as a stimulus to upper airway receptors. Ten minutes after the administration of oral benzocaine 20 mg the threshold response of the upper airway to ammonia (NH3TR) had risen significantly from baseline mean (SEM) of 680 (95) to 975 (109) ppm of ammonia with a return to baseline values after 25 min (n = 8, p < 0.05, repeated measures of ANOVA; p < 0.001, t-test). A direct spray of lignocaine 100 mg onto the vocal cords resulted in a significant elevation in NH3TR from a baseline mean (SEM) of 665 (81) to a maximum of 1600 (88) ppm of ammonia with a significant elevation in the threshold persisting for 100 min (n = 7, p < 0.001, repeated measures of ANOVA; p < 0.05, t-test). The application of 4% nebulised lignocaine 4 ml significantly increased NH3TR from a baseline mean (SEM) of 770 (56) to a maximum of 1190 (63) ppm of ammonia with a significant elevation in the threshold persisting for 30 min (n = 8, p < 0.001, repeated measures of ANOVA; p < 0.05, t-test). The maximum elevations in NH3TR with the two methods of lignocaine delivery were significantly different (p < 0.01, 2-way ANOVA).

Antinociception after both peripheral and intrathecal injection of oxotremorine is modulated by spinal nitric oxide.

PubMed

Machelska, H; Pavone, F; Capone, F; Przewłocka, B

1999-03-01

The present study investigated the role of spinal nitric oxide (NO) in the antinociception induced by intraperitoneal (i.p.) and intrathecal (i.th.) injection of oxotremorine. The experiments were carried out on male Wistar rats, which had cannulas chronically implanted in the lumbar enlargement of the spinal cord. Antinociceptive effects were evaluated using a tail-flick and a paw pressure test. To raise the spinal NO level, the rats received the NO donor, 3-morpholino-sydnonimine (SIN-1, 10 and 100 microg/5 microl); to lower the NO level, the inhibitor of NO synthase, N-nitro-L-arginine methyl ester (L-NAME, 50 and 400 microg/5 microl), was administered. Both those substances were injected i.th. Systemic injections of oxotremorine (0.02 and 0.1 mg/kg) produced a significant increase in the thermal nociceptive threshold, while the mechanical threshold was affected only by the higher dose (0.1 mg/kg) of the muscarinic agonist. I.th. injections of oxotremorine (0.1 ng, 1 ng, 1 microg/5 microl) produced significant antinociception in both those tests. I.th. administration of SIN-1 in doses which themselves did not affect the nociceptive threshold antagonized both the peripheral and central oxotremorine antinociception. I.th. administration of L-NAME (50 and 400 microg/5 microl) did not change the nociceptive threshold, but dose-dependently potentiated the effects of oxotremorine injected i.p. in both tests; however, the effect of i.th. administration of oxotremorine was potentiated only in the tail-flick test. Our results demonstrate that irrespective of the way of its injection, the antinociceptive effect of oxotremorine is modulated by activity of the spinal NO. Moreover, our results further support the hypothesis that NO present in the spinal cord exerts pronociceptive effects.

Noxious heat threshold temperature and pronociceptive effects of allyl isothiocyanate (mustard oil) in TRPV1 or TRPA1 gene-deleted mice.

PubMed

Tékus, Valéria; Horváth, Ádám; Hajna, Zsófia; Borbély, Éva; Bölcskei, Kata; Boros, Melinda; Pintér, Erika; Helyes, Zsuzsanna; Pethő, Gábor; Szolcsányi, János

2016-06-01

To investigate the roles of TRPV1 and TRPA1 channels in baseline and allyl isothiocyanate (AITC)-evoked nociceptive responses by comparing wild-type and gene-deficient mice. In contrast to conventional methods of thermonociception measuring reflex latencies, we used our novel methods to determine the noxious heat threshold. It was revealed that the heat threshold of the tail measured by an increasing-temperature water bath is significantly higher in TRPV1(-/-), but not TRPA1(-/-), mice compared to respective wild-types. There was no difference between the noxious heat thresholds of the hind paw as measured by an increasing-temperature hot plate in TRPV1(-/-), TRPA1(-/-) and the corresponding wild-type mice. The withdrawal latency of the tail from 0°C water was prolonged in TRPA1(-/-), but not TRPV1(-/-), mice compared to respective wild-types. In wild-type animals, dipping the tail or paw into 1% AITC induced an 8-14°C drop of the noxious heat threshold (heat allodynia) of both the tail and paw, and 40-50% drop of the mechanonociceptive threshold (mechanical allodynia) of the paw measured by dynamic plantar esthesiometry. These AITC-evoked responses were diminished in TRPV1(-/-), but not TRPA1(-/-), mice. Tail withdrawal latency to 1% AITC was significantly prolonged in both gene-deleted strains. Different heat sensors determine the noxious heat threshold in distinct areas: a pivotal role for TRPV1 on the tail is contrasted with no involvement of either TRPV1 or TRPA1 on the hind paw. Noxious heat threshold measurement appears appropriate for preclinical screening of TRP channel ligands as novel analgesics. Copyright © 2016 Elsevier Inc. All rights reserved.

Pleasure and pain: the effect of (almost) having an orgasm on genital and nongenital sensitivity.

PubMed

Paterson, Laurel Q P; Amsel, Rhonda; Binik, Yitzchak M

2013-06-01

The effect of sexual arousal and orgasm on genital sensitivity has received little research attention, and no study has assessed sensation pleasurableness as well as painfulness. To clarify the relationship between sexual arousal, orgasm, and sensitivity in a healthy female sample. Twenty-six women privately masturbated to orgasm and almost to orgasm at two separate sessions, during which standardized pressure stimulation was applied to the glans clitoris, vulvar vestibule, and volar forearm at three testing times: (i) baseline; (ii) immediately following masturbation; and (iii) following a subsequent 15-minute rest period. Touch thresholds (tactile detection sensitivity), sensation pleasurableness ratings (pleasurable sensitivity), and pain thresholds (pain sensitivity). Pleasurableness ratings were higher on the glans clitoris than the vulvar vestibule, and at most testing times on the vulvar vestibule than the volar forearm; and at baseline and immediately after masturbation than 15 minutes later, mainly on the genital locations only. Pain thresholds were lower on the genital locations than the volar forearm, and immediately and 15 minutes after masturbation than at baseline. After orgasm, genital pleasurableness ratings and vulvar vestibular pain thresholds were lower than after masturbation almost to orgasm. Post-masturbation pleasurableness ratings were positively correlated with pain thresholds but only on the glans clitoris. Hormonal contraception users had lower pleasurableness ratings and pain thresholds on all locations than nonusers. There were no significant effects for touch thresholds. Masturbation appears to maintain pleasurable genital sensitivity but increase pain sensitivity, with lower genital pleasurable sensitivity and higher vulvar vestibular pain sensitivity when orgasm occurs. Findings suggest that enhancing stimulation pleasurableness, psychological sexual arousal and lubrication mitigate normative increases in pain sensitivity during sexual activity, and underscore the importance of measuring both pleasure and pain in sensation research. © 2013 International Society for Sexual Medicine.

Cross-validation analysis for genetic evaluation models for ranking in endurance horses.

PubMed

García-Ballesteros, S; Varona, L; Valera, M; Gutiérrez, J P; Cervantes, I

2018-01-01

Ranking trait was used as a selection criterion for competition horses to estimate racing performance. In the literature the most common approaches to estimate breeding values are the linear or threshold statistical models. However, recent studies have shown that a Thurstonian approach was able to fix the race effect (competitive level of the horses that participate in the same race), thus suggesting a better prediction accuracy of breeding values for ranking trait. The aim of this study was to compare the predictability of linear, threshold and Thurstonian approaches for genetic evaluation of ranking in endurance horses. For this purpose, eight genetic models were used for each approach with different combinations of random effects: rider, rider-horse interaction and environmental permanent effect. All genetic models included gender, age and race as systematic effects. The database that was used contained 4065 ranking records from 966 horses and that for the pedigree contained 8733 animals (47% Arabian horses), with an estimated heritability around 0.10 for the ranking trait. The prediction ability of the models for racing performance was evaluated using a cross-validation approach. The average correlation between real and predicted performances across genetic models was around 0.25 for threshold, 0.58 for linear and 0.60 for Thurstonian approaches. Although no significant differences were found between models within approaches, the best genetic model included: the rider and rider-horse random effects for threshold, only rider and environmental permanent effects for linear approach and all random effects for Thurstonian approach. The absolute correlations of predicted breeding values among models were higher between threshold and Thurstonian: 0.90, 0.91 and 0.88 for all animals, top 20% and top 5% best animals. For rank correlations these figures were 0.85, 0.84 and 0.86. The lower values were those between linear and threshold approaches (0.65, 0.62 and 0.51). In conclusion, the Thurstonian approach is recommended for the routine genetic evaluations for ranking in endurance horses.

Lower thresholds for lifetime health effects in mammals from high-LET radiation - Comparison with chronic low-LET radiation.

PubMed

Sazykina, Tatiana G; Kryshev, Alexander I

2016-12-01

Lower threshold dose rates and confidence limits are quantified for lifetime radiation effects in mammalian animals from internally deposited alpha-emitting radionuclides. Extensive datasets on effects from internal alpha-emitters are compiled from the International Radiobiological Archives. In total, the compiled database includes 257 records, which are analyzed by means of non-parametric order statistics. The generic lower threshold for alpha-emitters in mammalian animals (combined datasets) is 6.6·10 -5  Gy day -1 . Thresholds for individual alpha-emitting elements differ considerably: plutonium and americium - 2.0·10 -5  Gy day -1 ; radium - 2.1·10 -4  Gy day -1 . Threshold for chronic low-LET radiation is previously estimated at 1·10 -3  Gy day -1 . For low exposures, the following values of alpha radiation weighting factor w R for internally deposited alpha-emitters in mammals are quantified: w R (α) = 15 as a generic value for the whole group of alpha-emitters; w R (Pu) = 50 for plutonium; w R (Am) = 50 for americium; w R (Ra) = 5 for radium. These values are proposed to serve as radiation weighting factors in calculations of equivalent doses to non-human biota. The lower threshold dose rate for long-lived mammals (dogs) is significantly lower than comparing with the threshold for short-lived mammals (mice): 2.7·10 -5  Gy day -1 , and 2.0·10 -4  Gy day -1 , respectively. The difference in thresholds is exactly reflecting the relationship between the natural longevity of these two species. Graded scale of severity in lifetime radiation effects in mammals is developed, based on compiled datasets. Being placed on the severity scale, the effects of internal alpha-emitters are situated in the zones of considerably lower dose rates than effects of the same severity caused by low-LET radiation. RBE values, calculated for effects of equal severity, are found to depend on the intensity of chronic exposure: different RBE values are characteristic for low, moderate, and high lifetime exposures (30, 70, and 13, respectively). The results of the study provide a basis for selecting correct values of radiation weighting factors in dose assessment to non-human biota. Copyright © 2016 Elsevier Ltd. All rights reserved.

Social laughter is correlated with an elevated pain threshold

PubMed Central

Dunbar, R. I. M.; Baron, Rebecca; Frangou, Anna; Pearce, Eiluned; van Leeuwen, Edwin J. C.; Stow, Julie; Partridge, Giselle; MacDonald, Ian; Barra, Vincent; van Vugt, Mark

2012-01-01

Although laughter forms an important part of human non-verbal communication, it has received rather less attention than it deserves in both the experimental and the observational literatures. Relaxed social (Duchenne) laughter is associated with feelings of wellbeing and heightened affect, a proximate explanation for which might be the release of endorphins. We tested this hypothesis in a series of six experimental studies in both the laboratory (watching videos) and naturalistic contexts (watching stage performances), using change in pain threshold as an assay for endorphin release. The results show that pain thresholds are significantly higher after laughter than in the control condition. This pain-tolerance effect is due to laughter itself and not simply due to a change in positive affect. We suggest that laughter, through an endorphin-mediated opiate effect, may play a crucial role in social bonding. PMID:21920973

Social laughter is correlated with an elevated pain threshold.

PubMed

Dunbar, R I M; Baron, Rebecca; Frangou, Anna; Pearce, Eiluned; van Leeuwen, Edwin J C; Stow, Julie; Partridge, Giselle; MacDonald, Ian; Barra, Vincent; van Vugt, Mark

2012-03-22

Although laughter forms an important part of human non-verbal communication, it has received rather less attention than it deserves in both the experimental and the observational literatures. Relaxed social (Duchenne) laughter is associated with feelings of wellbeing and heightened affect, a proximate explanation for which might be the release of endorphins. We tested this hypothesis in a series of six experimental studies in both the laboratory (watching videos) and naturalistic contexts (watching stage performances), using change in pain threshold as an assay for endorphin release. The results show that pain thresholds are significantly higher after laughter than in the control condition. This pain-tolerance effect is due to laughter itself and not simply due to a change in positive affect. We suggest that laughter, through an endorphin-mediated opiate effect, may play a crucial role in social bonding.

Cochlear implant characteristics and speech perception skills of adolescents with long-term device use.

PubMed

Davidson, Lisa S; Geers, Ann E; Brenner, Christine

2010-10-01

Updated cochlear implant technology and optimized fitting can have a substantial impact on speech perception. The effects of upgrades in processor technology and aided thresholds on word recognition at soft input levels and sentence recognition in noise were examined. We hypothesized that updated speech processors and lower aided thresholds would allow improved recognition of soft speech without compromising performance in noise. 109 teenagers who had used a Nucleus 22-cochlear implant since preschool were tested with their current speech processor(s) (101 unilateral and 8 bilateral): 13 used the Spectra, 22 the ESPrit 22, 61 the ESPrit 3G, and 13 the Freedom. The Lexical Neighborhood Test (LNT) was administered at 70 and 50 dB SPL and the Bamford Kowal Bench sentences were administered in quiet and in noise. Aided thresholds were obtained for frequency-modulated tones from 250 to 4,000 Hz. Results were analyzed using repeated measures analysis of variance. Aided thresholds for the Freedom/3G group were significantly lower (better) than the Spectra/Sprint group. LNT scores at 50 dB were significantly higher for the Freedom/3G group. No significant differences between the 2 groups were found for the LNT at 70 or sentences in quiet or noise. Adolescents using updated processors that allowed for aided detection thresholds of 30 dB HL or better performed the best at soft levels. The BKB in noise results suggest that greater access to soft speech does not compromise listening in noise.

Hemoglobin Concentration and the Risk of Death in Older Adults: Differences by Race/Ethnicity in the NHANES III Follow-up

PubMed Central

Patel, Kushang V.; Longo, Dan L.; Ershler, William B.; Yu, Binbing; Semba, Richard D.; Ferrucci, Luigi; Guralnik, Jack M.

2009-01-01

Summary Mildly low hemoglobin concentration is associated with increased mortality in older adults. However, this relationship has not been well characterized in racial/ethnic minorities. Therefore, this study determined the hemoglobin threshold below which risk of death is significantly increased in older non-Hispanic whites, non-Hispanic blacks, and Mexican Americans. Data on 4,089 participants of the 1988-1994 US National Health and Nutrition Examination Survey who were ≥65 years of age were analyzed with mortality follow-up through December 31, 2000. Mean hemoglobin in non-Hispanic whites (n=2,686) and Mexican Americans (n=663) was 140 g/L, while in non-Hispanic blacks (n=740) the mean was 10 g/L lower. A total of 1,944 (47.5%) participants died. Among non-Hispanic whites and Mexican Americans, age- and sex-adjusted models showed that the hemoglobin thresholds below which mortality risk was significantly increased were 4 g/L and 2 g/L, respectively, above the World Health Organization (WHO) cutoffs for anaemia. In contrast, the threshold for non-Hispanic blacks was 7 g/L below the WHO criteria. Similar threshold effects were observed when analyzing hemoglobin in categories and adjusting for multiple confounders. In conclusion, the hemoglobin threshold below which mortality rises significantly is a full g/dL lower in non-Hispanic blacks than in non-Hispanic whites and Mexican Americans. PMID:19344387

Influence of different frequencies of transcutaneous electrical nerve stimulation on the threshold and pain intensity in young subjects

PubMed Central

Gomes, Adriana de Oliveira; Silvestre, Ana Caroline; da Silva, Cristina Ferreira; Gomes, Mariany Ribeiro; Bonfleur, Maria Lúcia; Bertolini, Gladson Ricardo Flor

2014-01-01

Objective To investigate the effects of different transcutaneous electrical nerve stimulation frequencies in nociception front of a pressure pain threshold and cold in healthy individuals. Methods Twenty healthy subjects were divided into four groups, all of which have gone through all forms of electrical stimulation at different weeks. Assessments were pre and post-therapy, 20 and 60 minutes after stimulation. To evaluate the pressure pain threshold, an algometer was used with one tapered tip, pressing the hypothenar region until voluntary report the word “pain”. Cold pain intensity was assessed by immersion in water at 5°C for 30 seconds; at the end, the subject was asked to quantify the pain intensity on a Visual Analog Scale for Pain. For electrical stimulation, two electrodes were used near the elbow, for 20 minutes, with an intensity strong, but not painful. The frequency was in accordance with the group: 0Hz (placebo); 7Hz; 100Hz; and 255Hz. Results Both for the assessment of pressure pain threshold as the cold pain intensity, there was no significant difference (p>0.05). Conclusion We conclude that the use of transcutaneous electrical nerve stimulation on dermatomes C6 to C8 produced no significant change in pressure pain threshold or cold discomfort. PMID:25295453

Psychophysical estimation of the effects of aging on direction-of-heading judgments

NASA Astrophysics Data System (ADS)

Raghuram, Aparna; Lakshminarayanan, Vasudevan

2011-11-01

We conducted psychophysical experiments on direction-of-heading judgments using old and young subjects. Subjects estimated heading directions on a translation perpendicular to the vertical plane (frontoparallel); we found that heading judgments were affected by age. Increasing the random dot density in the stimulus from 24 to 400 dots did not improve threshold significantly. Older subjects started performing worse at the highest dots condition of 400. The speed of the radial motion was important, as heading judgments with slower radial motion were difficult to judge than faster radial motion, as the focus of expansion was easier to locate owing to the larger displacement of dots. Gender differences indicated that older women had a higher threshold than older men. This was only significant for the faster simulated radial speed. A general trend of women having a higher threshold than men was noticed.

Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Somatosensory and Laser Evoked Potentials.

PubMed

Jones, Matthew D; Taylor, Janet L; Booth, John; Barry, Benjamin K

2016-01-01

Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1-SEPs; Experiment 2-LEPs) by increased pressure pain thresholds at biceps brachii (24.3 and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p < 0.001) and first dorsal interosseous (18.8 and 21.5% increase in Experiment 1 and 2, respectively; both d > 0.57 and p < 0.001). In contrast, heat pain thresholds were not significantly different after exercise (forearm: 10.8% increase, d = 0.35, p = 0.10; hand: 3.6% increase, d = 0.06, p = 0.74). Contrasting effects of exercise on the amplitude of laser evoked potentials (14.6% decrease, d = -0.42, p = 0.004) and somatosensory evoked potentials (10.9% increase, d = -0.02, p = 1) were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = -0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = -0.32, p = 0.006). The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia.

Doctoral conceptual thresholds in cellular and molecular biology

NASA Astrophysics Data System (ADS)

Feldon, David F.; Rates, Christopher; Sun, Chongning

2017-12-01

In the biological sciences, very little is known about the mechanisms by which doctoral students acquire the skills they need to become independent scientists. In the postsecondary biology education literature, identification of specific skills and effective methods for helping students to acquire them are limited to undergraduate education. To establish a foundation from which to investigate the developmental trajectory of biologists' research skills, it is necessary to identify those skills which are integral to doctoral study and distinct from skills acquired earlier in students' educational pathways. In this context, the current study engages the framework of threshold concepts to identify candidate skills that are both obstacles and significant opportunities for developing proficiency in conducting research. Such threshold concepts are typically characterised as transformative, integrative, irreversible, and challenging. The results from interviews and focus groups with current and former doctoral students in cellular and molecular biology suggest two such threshold concepts relevant to their subfield: the first is an ability to effectively engage primary research literature from the biological sciences in a way that is critical without dismissing the value of its contributions. The second is the ability to conceptualise appropriate control conditions necessary to design and interpret the results of experiments in an efficient and effective manner for research in the biological sciences as a discipline. Implications for prioritising and sequencing graduate training experiences are discussed on the basis of the identified thresholds.

Thresholds and criteria for evaluating and communicating impact significance in environmental statements: 'See no evil, hear no evil, speak no evil'?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, Graham

2008-01-15

The evaluation and communication of the significance of environmental effects remains a critical yet poorly understood component of EIA theory and practice. Following a conceptual overview of the generic dimensions of impact significance in EIA, this paper reports upon the findings of an empirical study of recent environmental impact statements that considers the treatment of significance for impacts concerning landscape ('see no evil') and noise ('hear no evil'), focussing specifically upon the evaluation and communication of impact significance ('speak no evil') in UK practice. Particular attention is given to the use of significance criteria and thresholds, including the development ofmore » a typology of approaches applied within the context of noise and landscape/visual impacts. Following a broader discussion of issues surrounding the formulation, application and interpretation of significance criteria, conclusions and recommendations relevant to wider EIA practice are suggested.« less

Protective Effects of α-Tocopherol on ABR Threshold Shift in Rabbits Exposed to Noise and Carbon Monoxide.

PubMed

Motallebi Kashani, Masoud; Mortazavi, Seyyed Bagher; Khavanin, Ali; Allameh, Abdolamir; Mirzaee, Ramezan; Akbari, Mehdi

2011-01-01

Noise induced hearin gloss (NIHL) is one of the most important occupational disease world wide. NIHL has been found potentiate by simultaneous carbon monoxide (CO) exposure. Free radicals have been implicated in cochlear damage resulted from the exposure to noise and due to the CO hypoxia. This study examined whether α-tocopherol administration , as a free radical scavenger, causes the attenuation of auditory brainstem response (ABR) threshold shifts resulting from noise exposure and noise plus CO exposure. Forty-two rabbits were divided in to seven groups including control, noise + saline, noise + CO + saline, noise + α-tocopherol, noise + CO + α-tocopherol , CO + α-tocopherol and α-tocopherol alone. ABR was assessed before exposure, 1 hand 14 days post exposure. The administration of 50 mg/Kg of α-tocopherol prior, following and post exposure to noise or noise plus CO recovered permanent ABR threshold shift at 1 and KHz almost to the baseline and provided significant attenuation in permanent ABR threshold shift at 4 and 8 KHz in subject swhich were exposed to noise but it did not block the potentiating of threshold elevation by CO exposure (extra threshold loss by combined exposure) at 4 and 8 KHz. α Tocopherol provides protective effect against the hearing loss resulting from noise exposure and simultaneous exposure to noise plus CO.

Effectiveness of the hearing conservation program: Change in hearing threshold shift incidence among industrial workers, 1978 to 2003

NASA Astrophysics Data System (ADS)

Davies, Hugh

2005-04-01

Hearing conservation programs (HCP) are widely employed in preventing noise-induced hearing loss, but studies of their effectiveness have been rare. The impact of the implementation of hearing conservation programs was assessed in a large group of highly noise-exposed blue-collar workers by investigating time-trends in hearing-threshold shift incidence. Serial annual audiograms for employees of 14 British Columbia lumber mills for the period 1978 to 2003 were obtained from local regulatory-agency archives. Audiograms and concomitant otological medical histories were linked to subjects' work histories and noise exposure data. Multivariable Cox proportional hazard models were used to model the incidence of hearing threshold shift while controlling for age, baseline level of hearing loss, and other potential confounders. A total of 109257 audiograms were associated with 10590 subjects. Mean noise exposure in this group was 91.4 dBA(A). Mean interval between hearing tests was 566 days and mean age at first threshold shift was 44. Forty-six percent of subjects had at least one OSHA significant threshold shift during follow up. Preliminary analyses indicated a trend toward lower incidence of threshold shifts over the study period, with incidence in 5 approximately equal 5-year periods from 1978 to 2003 being 3.2%, 6.6%, 4.9%, 4.3% and 2.4%, respectively.

SNW 2000 Proceedings. Oxide Thickness Variation Induced Threshold Voltage Fluctuations in Decanano MOSFETs: a 3D Density Gradient Simulation Study

NASA Technical Reports Server (NTRS)

Asenov, Asen; Kaya, S.; Davies, J. H.; Saini, S.

2000-01-01

We use the density gradient (DG) simulation approach to study, in 3D, the effect of local oxide thickness fluctuations on the threshold voltage of decanano MOSFETs in a statistical manner. A description of the reconstruction procedure for the random 2D surfaces representing the 'atomistic' Si-SiO2 interface variations is presented. The procedure is based on power spectrum synthesis in the Fourier domain and can include either Gaussian or exponential spectra. The simulations show that threshold voltage variations induced by oxide thickness fluctuation become significant when the gate length of the devices become comparable to the correlation length of the fluctuations. The extent of quantum corrections in the simulations with respect to the classical case and the dependence of threshold variations on the oxide thickness are examined.

Sensitivity to coincidences and paranormal belief.

PubMed

Hadlaczky, Gergö; Westerlund, Joakim

2011-12-01

Often it is difficult to find a natural explanation as to why a surprising coincidence occurs. In attempting to find one, people may be inclined to accept paranormal explanations. The objective of this study was to investigate whether people with a lower threshold for being surprised by coincidences have a greater propensity to become believers compared to those with a higher threshold. Participants were exposed to artificial coincidences, which were formally defined as less or more probable, and were asked to provide remarkability ratings. Paranormal belief was measured by the Australian Sheep-Goat Scale. An analysis of the remarkability ratings revealed a significant interaction effect between Sheep-Goat score and type of coincidence, suggesting that people with lower thresholds of surprise, when experiencing coincidences, harbor higher paranormal belief than those with a higher threshold. The theoretical aspects of these findings were discussed.

77 FR 1969 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing and Immediate Effectiveness of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-12

... Numerical Thresholds With Percentage Thresholds for the Investor Tiers' Volume Requirements January 6, 2012... replace numerical thresholds with percentage thresholds for the Investor Tiers' volume requirements. The...: Replacing Numerical Thresholds With Percentage Thresholds Effective June 1, 2011, NYSE Arca introduced two...

Multi-parameter analysis of titanium vocal fold medializing implant in an excised larynx model

PubMed Central

Witt, Rachel E.; Hoffman, Matthew R.; Friedrich, Gerhard; Rieves, Adam L.; Schoepke, Benjamin J.; Jiang, Jack J.

2010-01-01

Objective Evaluate the efficacy of the titanium vocal fold medializing implant (TVFMI) for the treatment of unilateral vocal fold paralysis (UVFP) based on acoustic, aerodynamic, and mucosal wave measurements in an excised larynx setup. Methods Measurements were recorded on eight excised canine larynges with simulated UVFP before and after medialization with the TVFMI. Results Phonation threshold flow (PTF) and phonation threshold power (PTW) decreased significantly after medialization (p<0.001; p=0.008). Phonation threshold pressure (PTP) also decreased, but this difference was not significant (p=0.081). Percent jitter and percent shimmer decreased significantly after medialization (p=0.005; p=0.034). Signal to noise ratio (SNR) increased significantly (p=0.05). Differences in mucosal wave characteristics were discernable, but not significant. Phase difference between the normal and paralyzed vocal fold and amplitude of the paralyzed vocal fold decreased (p=0.15; p=0.78). Glottal gap decreased significantly (p=0.004). Conclusions The TVFMI was effective in achieving vocal fold medialization, improving vocal aerodynamic and acoustic characteristics of phonation significantly and mucosal wave characteristics discernibly. This study provides objective, quantitative support for the use of the TVFMI in improving vocal function in patients with unilateral vocal fold paralysis. PMID:20336924

Thermal antinociception after dexmedetomidine administration in cats: a dose-finding study.

PubMed

Slingsby, L S; Taylor, P M

2008-04-01

The optimum dose of dexmedetomidine for antinociception to a thermal stimulus was determined in a crossover study of 12 cats. In five treatment groups (n = 10 per group), dexmedetomidine was administered intramuscularly (i.m.) at 2, 5, 10, 20 and 40 microg/kg; positive and negative controls were administered buprenorphine (20 microg/kg, i.m.) and 0.9% saline (0.006 mL/kg, i.m.) respectively. Baseline thermal thresholds and visual analogue scale (VAS) sedation scores were obtained prior to drug treatment and then at regular intervals until 24 h after administration. The summary measures of overall mean thresholds and overall mean VAS scores were investigated using a univariate general linear model for multiple factors with post hoc Tukey's tests (P < 0.05). Only dexmedetomidine at 40 microg/kg displayed an analgesic effect (less than that of buprenorphine). The VAS for sedation did not significantly affect the thresholds obtained and treatment was the only significant factor to influence VAS. Dexmedetomidine resulted in higher VAS for sedation than saline and buprenorphine. Dexmedetomidine at 40 microg/kg significantly increased nociceptive thresholds compared with saline control, but less than buprenorphine. Dexmedetomidine produced dose-dependent sedation, but only the highest dose produced analgesia, suggesting that induction of analgesia requires the highest dose (or an additional analgesic) in the clinical setting.

Defining thresholds of sustainable impact on benthic communities in relation to fishing disturbance.

PubMed

Lambert, G I; Murray, L G; Hiddink, J G; Hinz, H; Lincoln, H; Hold, N; Cambiè, G; Kaiser, M J

2017-07-14

While the direct physical impact on seabed biota is well understood, no studies have defined thresholds to inform an ecosystem-based approach to managing fishing impacts. We addressed this knowledge gap using a large-scale experiment that created a controlled gradient of fishing intensity and assessed the immediate impacts and short-term recovery. We observed a mosaic of taxon-specific responses at various thresholds. The lowest threshold of significant lasting impact occurred between 1 and 3 times fished and elicited a decrease in abundance of 39 to 70% for some sessile epifaunal organisms (cnidarians, bryozoans). This contrasted with significant increases in abundance and/or biomass of scavenging species (epifaunal echinoderms, infaunal crustaceans) by two to four-fold in areas fished twice and more. In spite of these significant specific responses, the benthic community structure, biomass and abundance at the population level appeared resilient to fishing. Overall, natural temporal variation in community metrics exceeded the effects of fishing in this highly dynamic study site, suggesting that an acute level of disturbance (fished over six times) would match the level of natural variation. We discuss the implications of our findings for natural resources management with respect to context-specific human disturbance and provide guidance for best fishing practices.

No effects of hydrocortisone and dexamethasone on pain sensitivity in healthy individuals.

PubMed

Wingenfeld, K; Wolf, S; Kunz, M; Krieg, J-C; Lautenbacher, S

2015-07-01

There is some evidence that stress-induced cortisol increase leads to a decrease in pain, while lowering cortisol levels enhances pain sensitivity, but no study has yet investigated both pharmacological enhancement and reduction of cortisol levels in the same individuals. Firstly, we tested in 16 healthy individuals whether the treatment with hydrocortisone and dexamethasone, respectively, results in altered pain thresholds. Secondly, we aimed to test whether hormone effects are different across the pain range by using ratings for pain stimuli with varying intensity; and thirdly, we tested whether cortisol levels influence the discrimination ability for painful stimuli. Despite substantial effects of dexamethasone and hydrocortisone administration on cortisol levels, no effect of these drugs was seen in terms of pain sensitivity (pain threshold, pain rating, pain discrimination ability), although comprehensively examined. However, in the placebo condition, a significant negative correlation between cortisol and pain thresholds was seen. Similarly, there were also strong negative associations between cortisol levels in the placebo condition and pain thresholds after drug treatment (especially after hydrocortisone). These findings suggest that short-term variations of cortisol do not influence pain sensitivity whereas, in general, high levels of cortisol are associated with increased pain sensitivity, at least for weak to moderate stimuli. © 2014 European Pain Federation - EFIC®

Extreme sub-threshold swing in tunnelling relays

NASA Astrophysics Data System (ADS)

AbdelGhany, M.; Szkopek, T.

2014-01-01

We propose and analyze the theory of the tunnelling relay, a nanoscale active device in which tunnelling current is modulated by electromechanical actuation of a suspended membrane above a fixed electrode. The tunnelling current is modulated exponentially with vacuum gap length, permitting an extreme sub-threshold swing of ˜10 mV/decade breaking the thermionic limit. The predicted performance suggests that a significant reduction in dynamic energy consumption over conventional field effect transistors is physically achievable.

Acute effects of dynamic exercises on the relationship between the motor unit firing rate and the recruitment threshold.

PubMed

Ye, Xin; Beck, Travis W; DeFreitas, Jason M; Wages, Nathan P

2015-04-01

The aim of this study was to compare the acute effects of concentric versus eccentric exercise on motor control strategies. Fifteen men performed six sets of 10 repetitions of maximal concentric exercises or eccentric isokinetic exercises with their dominant elbow flexors on separate experimental visits. Before and after the exercise, maximal strength testing and submaximal trapezoid isometric contractions (40% of the maximal force) were performed. Both exercise conditions caused significant strength loss in the elbow flexors, but the loss was greater following the eccentric exercise (t=2.401, P=.031). The surface electromyographic signals obtained from the submaximal trapezoid isometric contractions were decomposed into individual motor unit action potential trains. For each submaximal trapezoid isometric contraction, the relationship between the average motor unit firing rate and the recruitment threshold was examined using linear regression analysis. In contrast to the concentric exercise, which did not cause significant changes in the mean linear slope coefficient and y-intercept of the linear regression line, the eccentric exercise resulted in a lower mean linear slope and an increased mean y-intercept, thereby indicating that increasing the firing rates of low-threshold motor units may be more important than recruiting high-threshold motor units to compensate for eccentric exercise-induced strength loss. Copyright © 2014 Elsevier B.V. All rights reserved.

Defining indoor heat thresholds for health in the UK.

PubMed

Anderson, Mindy; Carmichael, Catriona; Murray, Virginia; Dengel, Andy; Swainson, Michael

2013-05-01

It has been recognised that as outdoor ambient temperatures increase past a particular threshold, so do mortality/morbidity rates. However, similar thresholds for indoor temperatures have not yet been identified. Due to a warming climate, the non-sustainability of air conditioning as a solution, and the desire for more energy-efficient airtight homes, thresholds for indoor temperature should be defined as a public health issue. The aim of this paper is to outline the need for indoor heat thresholds and to establish if they can be identified. Our objectives include: describing how indoor temperature is measured; highlighting threshold measurements and indices; describing adaptation to heat; summary of the risk of susceptible groups to heat; reviewing the current evidence on the link between sleep, heat and health; exploring current heat and health warning systems and thresholds; exploring the built environment and the risk of overheating; and identifying the gaps in current knowledge and research. A global literature search of key databases was conducted using a pre-defined set of keywords to retrieve peer-reviewed and grey literature. The paper will apply the findings to the context of the UK. A summary of 96 articles, reports, government documents and textbooks were analysed and a gap analysis was conducted. Evidence on the effects of indoor heat on health implies that buildings are modifiers of the effect of climate on health outcomes. Personal exposure and place-based heat studies showed the most significant correlations between indoor heat and health outcomes. However, the data are sparse and inconclusive in terms of identifying evidence-based definitions for thresholds. Further research needs to be conducted in order to provide an evidence base for threshold determination. Indoor and outdoor heat are related but are different in terms of language and measurement. Future collaboration between the health and building sectors is needed to develop a common language and an index for indoor heat and health thresholds in a changing climate.

Psychophysics with children: Investigating the effects of attentional lapses on threshold estimates.

PubMed

Manning, Catherine; Jones, Pete R; Dekker, Tessa M; Pellicano, Elizabeth

2018-03-26

When assessing the perceptual abilities of children, researchers tend to use psychophysical techniques designed for use with adults. However, children's poorer attentiveness might bias the threshold estimates obtained by these methods. Here, we obtained speed discrimination threshold estimates in 6- to 7-year-old children in UK Key Stage 1 (KS1), 7- to 9-year-old children in Key Stage 2 (KS2), and adults using three psychophysical procedures: QUEST, a 1-up 2-down Levitt staircase, and Method of Constant Stimuli (MCS). We estimated inattentiveness using responses to "easy" catch trials. As expected, children had higher threshold estimates and made more errors on catch trials than adults. Lower threshold estimates were obtained from psychometric functions fit to the data in the QUEST condition than the MCS and Levitt staircases, and the threshold estimates obtained when fitting a psychometric function to the QUEST data were also lower than when using the QUEST mode. This suggests that threshold estimates cannot be compared directly across methods. Differences between the procedures did not vary significantly with age group. Simulations indicated that inattentiveness biased threshold estimates particularly when threshold estimates were computed as the QUEST mode or the average of staircase reversals. In contrast, thresholds estimated by post-hoc psychometric function fitting were less biased by attentional lapses. Our results suggest that some psychophysical methods are more robust to attentiveness, which has important implications for assessing the perception of children and clinical groups.

Effects of Temperature on the Histotripsy Intrinsic Threshold for Cavitation.

PubMed

Vlaisavljevich, Eli; Xu, Zhen; Maxwell, Adam; Mancia, Lauren; Zhang, Xi; Lin, Kuang-Wei; Duryea, Alexander; Sukovich, Jonathan; Hall, Tim; Johnsen, Eric; Cain, Charles

2016-05-10

Histotripsy is an ultrasound ablation method that depends on the initiation of a dense cavitation bubble cloud to fractionate soft tissue. Previous work has demonstrated that a cavitation cloud can be formed by a single acoustic pulse with one high amplitude negative cycle, when the negative pressure amplitude exceeds a threshold intrinsic to the medium. The intrinsic thresholds in soft tissues and tissue phantoms that are water-based are similar to the intrinsic threshold of water over an experimentally verified frequency range of 0.3-3 MHz. Previous work studying the histotripsy intrinsic threshold has been limited to experiments performed at room temperature (~20°C). In this study, we investigate the effects of temperature on the histotripsy intrinsic threshold in water, which is essential to accurately predict the intrinsic thresholds expected over the full range of in vivo therapeutic temperatures. Based on previous work studying the histotripsy intrinsic threshold and classical nucleation theory, we hypothesize that the intrinsic threshold will decrease with increasing temperature. To test this hypothesis, the intrinsic threshold in water was investigated both experimentally and theoretically. The probability of generating cavitation bubbles was measured by applying a single pulse with one high amplitude negative cycle at 1 MHz to distilled, degassed water at temperatures ranging from 10°C-90°C. Cavitation was detected and characterized by passive cavitation detection and high-speed photography, from which the probability of cavitation was measured vs. pressure amplitude. The results indicate that the intrinsic threshold (the negative pressure at which the cavitation probability=0.5) significantly decreases with increasing temperature, showing a nearly linear decreasing trend from 29.8±0.4 MPa at 10˚C to 14.9±1.4 MPa at 90˚C. Overall, the results of this study support our hypothesis that the intrinsic threshold is highly dependent upon the temperature of the medium, which may allow for better predictions of cavitation generation at body temperature in vivo and at the elevated temperatures commonly seen in high intensity focused ultrasound (HIFU) regimes.

Effects of Temperature on the Histotripsy Intrinsic Threshold for Cavitation

PubMed Central

Vlaisavljevich, Eli; Xu, Zhen; Maxwell, Adam; Mancia, Lauren; Zhang, Xi; Lin, Kuang-Wei; Duryea, Alexander; Sukovich, Jonathan; Hall, Tim; Johnsen, Eric; Cain, Charles

2018-01-01

Histotripsy is an ultrasound ablation method that depends on the initiation of a dense cavitation bubble cloud to fractionate soft tissue. Previous work has demonstrated that a cavitation cloud can be formed by a single acoustic pulse with one high amplitude negative cycle, when the negative pressure amplitude exceeds a threshold intrinsic to the medium. The intrinsic thresholds in soft tissues and tissue phantoms that are water-based are similar to the intrinsic threshold of water over an experimentally verified frequency range of 0.3–3 MHz. Previous work studying the histotripsy intrinsic threshold has been limited to experiments performed at room temperature (~ 20°C). In this study, we investigate the effects of temperature on the histotripsy intrinsic threshold in water, which is essential to accurately predict the intrinsic thresholds expected over the full range of in vivo therapeutic temperatures. Based on previous work studying the histotripsy intrinsic threshold and classical nucleation theory, we hypothesize that the intrinsic threshold will decrease with increasing temperature. To test this hypothesis, the intrinsic threshold in water was investigated both experimentally and theoretically. The probability of generating cavitation bubbles was measured by applying a single pulse with one high amplitude negative cycle at 1 MHz to distilled, degassed water at temperatures ranging from 10°C–90°C. Cavitation was detected and characterized by passive cavitation detection and high-speed photography, from which the probability of cavitation was measured vs. pressure amplitude. The results indicate that the intrinsic threshold (the negative pressure at which the cavitation probability = 0.5) significantly decreases with increasing temperature, showing a nearly linear decreasing trend from 29.8±0.4 MPa at 10°C to 14.9±1.4 MPa at 90°C. Overall, the results of this study support our hypothesis that the intrinsic threshold is highly dependent upon the temperature of the medium, which may allow for better predictions of cavitation generation at body temperature in vivo and at the elevated temperatures commonly seen in high intensity focused ultrasound (HIFU) regimes. PMID:28113706

Identifying Thresholds for Ecosystem-Based Management

PubMed Central

Samhouri, Jameal F.; Levin, Phillip S.; Ainsworth, Cameron H.

2010-01-01

Background One of the greatest obstacles to moving ecosystem-based management (EBM) from concept to practice is the lack of a systematic approach to defining ecosystem-level decision criteria, or reference points that trigger management action. Methodology/Principal Findings To assist resource managers and policymakers in developing EBM decision criteria, we introduce a quantitative, transferable method for identifying utility thresholds. A utility threshold is the level of human-induced pressure (e.g., pollution) at which small changes produce substantial improvements toward the EBM goal of protecting an ecosystem's structural (e.g., diversity) and functional (e.g., resilience) attributes. The analytical approach is based on the detection of nonlinearities in relationships between ecosystem attributes and pressures. We illustrate the method with a hypothetical case study of (1) fishing and (2) nearshore habitat pressure using an empirically-validated marine ecosystem model for British Columbia, Canada, and derive numerical threshold values in terms of the density of two empirically-tractable indicator groups, sablefish and jellyfish. We also describe how to incorporate uncertainty into the estimation of utility thresholds and highlight their value in the context of understanding EBM trade-offs. Conclusions/Significance For any policy scenario, an understanding of utility thresholds provides insight into the amount and type of management intervention required to make significant progress toward improved ecosystem structure and function. The approach outlined in this paper can be applied in the context of single or multiple human-induced pressures, to any marine, freshwater, or terrestrial ecosystem, and should facilitate more effective management. PMID:20126647

Spatial contrast sensitivity vision loss in children with cortical visual impairment.

PubMed

Good, William V; Hou, Chuan; Norcia, Anthony M

2012-11-19

Although cortical visual impairment (CVI) is the leading cause of bilateral vision impairment in children in Western countries, little is known about the effects of CVI on visual function. The aim of this study was to compare visual evoked potential measures of contrast sensitivity and grating acuity in children with CVI with those of age-matched typically developing controls. The swept parameter visual evoked potential (sVEP) was used to measure contrast sensitivity and grating acuity in 34 children with CVI at 5 months to 5 years of age and in 16 age-matched control children. Contrast thresholds and spatial frequency thresholds (grating acuities) were derived by extrapolating the tuning functions to zero amplitude. These thresholds and maximal suprathreshold response amplitudes were compared between groups. Among 34 children with CVI, 30 had measurable but reduced contrast sensitivity with a median threshold of 10.8% (range 5.0%-30.0% Michelson), and 32 had measurable but reduced grating acuity with median threshold 0.49 logMAR (9.8 c/deg, range 5-14 c/deg). These thresholds were significantly reduced, compared with age-matched control children. In addition, response amplitudes over the entire sweep range for both measures were significantly diminished in children with CVI compared with those of control children. Our results indicate that spatial contrast sensitivity and response amplitudes are strongly affected by CVI. The substantial degree of loss in contrast sensitivity suggests that contrast is a sensitive measure for evaluating vision deficits in patients with CVI.

Doxapram Only Slightly Reduces the Shivering Threshold in Healthy Volunteers

PubMed Central

Komatsu, Ryu; Sengupta, Papiya; Cherynak, Grigory; Wadhwa, Anupama; Sessler, Daniel I.; Liu, Jin; Hurst, Harrell E.; Lenhardt, Rainer

2005-01-01

We determined the effects of doxapram on the major autonomic thermoregulatory responses in humans. Nine healthy volunteers were studied on two days: Control and Doxapram (intravenous infusion to a plasma concentration of 2.4 ±0.8 μg/mL, 2.5 ±0.9 μg/mL, and 2.6 ±1.1 μg/mL at the sweating, vasoconstriction, and shivering thresholds, respectively). Each day, skin and core temperatures were increased to provoke sweating, then reduced to elicit peripheral vasoconstriction and shivering. We determined the sweating, vasoconstriction, and shivering thresholds with compensation for changes in skin temperature. Data were analyzed with paired t tests and presented as means ± SDs; P < 0.05 was considered statistically significant. Doxapram did not change the sweating (Control: 37.5±0.4°C, Doxapram: 37.3±0.4°C, P=0.290) or the vasoconstriction threshold (36.8±0.7 vs. 36.4±0.5°C; P=0.110). However, it significantly reduced the shivering threshold from 36.2±0.5 to 35.7±0.7°C (P=0.012). No sedation or symptoms of panic were observed on either study day. The observed reduction in the shivering threshold explains the drug's efficacy for treatment of postoperative shivering; however, a reduction of only 0.5°C is unlikely to markedly facilitate induction of therapeutic hypothermia as a sole agent. PMID:16243996

Wind erosion in semiarid landscapes: Predictive models and remote sensing methods for the influence of vegetation

NASA Technical Reports Server (NTRS)

Musick, H. Brad; Truman, C. Randall; Trujillo, Steven M.

1992-01-01

Wind erosion in semi-arid regions is a significant problem for which the sheltering effect of rangeland vegetation is poorly understood. Individual plants may be considered as porous roughness elements which absorb or redistribute the wind's momentum. The saltation threshold is the minimum wind velocity at which soil movement begins. The dependence of the saltation threshold on geometrical parameters of a uniform roughness array was studied in a wind tunnel. Both solid and porous elements were used to determine relationships between canopy structure and the threshold velocity for soil transport. The development of a predictive relation for the influence of vegetation canopy structure on wind erosion of soil is discussed.

Genetic parameters for direct and maternal calving ease in Walloon dairy cattle based on linear and threshold models.

PubMed

Vanderick, S; Troch, T; Gillon, A; Glorieux, G; Gengler, N

2014-12-01

Calving ease scores from Holstein dairy cattle in the Walloon Region of Belgium were analysed using univariate linear and threshold animal models. Variance components and derived genetic parameters were estimated from a data set including 33,155 calving records. Included in the models were season, herd and sex of calf × age of dam classes × group of calvings interaction as fixed effects, herd × year of calving, maternal permanent environment and animal direct and maternal additive genetic as random effects. Models were fitted with the genetic correlation between direct and maternal additive genetic effects either estimated or constrained to zero. Direct heritability for calving ease was approximately 8% with linear models and approximately 12% with threshold models. Maternal heritabilities were approximately 2 and 4%, respectively. Genetic correlation between direct and maternal additive effects was found to be not significantly different from zero. Models were compared in terms of goodness of fit and predictive ability. Criteria of comparison such as mean squared error, correlation between observed and predicted calving ease scores as well as between estimated breeding values were estimated from 85,118 calving records. The results provided few differences between linear and threshold models even though correlations between estimated breeding values from subsets of data for sires with progeny from linear model were 17 and 23% greater for direct and maternal genetic effects, respectively, than from threshold model. For the purpose of genetic evaluation for calving ease in Walloon Holstein dairy cattle, the linear animal model without covariance between direct and maternal additive effects was found to be the best choice. © 2014 Blackwell Verlag GmbH.

A randomized trial of the effect of automated ventricular capture on device longevity and threshold measurement in pacemaker patients.

PubMed

Koplan, Bruce A; Gilligan, David M; Nguyen, Luc S; Lau, Theodore K; Thackeray, Lisa M; Berg, Kellie Chase

2008-11-01

An automatic capture (AC) algorithm adjusts ventricular pacing output to capture the ventricle while optimizing output to 0.5 V above threshold. AC maintains this output and confirms capture on a beat-to-beat basis in bipolar and unipolar pacing and sensing. To assess the AC algorithm and its impact on device longevity. Patients implanted with a pacemaker were randomized 1:1 to have the AC feature on or off for 12 months. Two threshold tests were conducted at each visit- automatic threshold and manual threshold. Average ventricular voltage output and projected device longevity were compared between AC on and off using nonparametric tests. Nine hundred ten patients were enrolled and underwent device implantation. Average ventricular voltage output was 1.6 V for the AC on arm (n = 444) and 3.1 V for the AC off arm (n = 446) (P < 0.001). Projected device longevity was 10.3 years for AC on and 8.9 years for AC off (P < 0.0001), or a 16% increase in longevity for AC on. The proportion of patients in whom there was a difference between automatic threshold and manual threshold of

The effect of culture on pain sensitivity.

PubMed

Al-Harthy, M; Ohrbach, R; Michelotti, A; List, T

2016-02-01

Cross-cultural differences in pain sensitivity have been identified in pain-free subjects as well as in chronic pain patients. The aim was to assess the impact of culture on psychophysical measures using mechanical and electrical stimuli in patients with temporomandibular disorder (TMD) pain and pain-free matched controls in three cultures. This case-control study compared 122 female cases of chronic TMD pain (39 Saudis, 41 Swedes and 42 Italians) with equal numbers of age- and gender-matched TMD-free controls. Pressure pain threshold (PPT) and tolerance (PPTo) were measured over one hand and two masticatory muscles. Electrical perception threshold and electrical pain threshold (EPT) and tolerance (EPTo) were recorded between the thumb and index fingers. Italian females reported significantly lower PPT in the masseter muscle than other cultures (P < 0.001) and in the temporalis muscle than Saudis (P = 0.003). Swedes reported significantly higher PPT in the thenar muscle than other cultures (P = 0.017). Italians reported significantly lower PPTo in all muscles than Swedes (P ≤ 0.006) and in the masseter muscle than Saudis (P < 0.001). Italians reported significantly lower EPTo than other cultures (P = 0.01). Temporomandibular disorder cases, compared to TMD-free controls, reported lower PPT and PPTo in all the three muscles (P < 0.001). This study found cultural differences between groups in the PPT, PPTo and EPTo. Overall, Italian females reported the highest sensitivity to both mechanical and electrical stimulation, while Swedes reported the lowest sensitivity. Mechanical pain thresholds differed more across cultures than did electrical pain thresholds. Cultural factors may influence response to type of pain test. © 2015 John Wiley & Sons Ltd.

Magnesium Sulfate Only Slightly Reduces the Shivering Threshold in Humans

PubMed Central

Wadhwa, Anupama; Sengupta, Papiya; Durrani, Jaleel; Akça, Ozan; Lenhardt, Rainer; Sessler, Daniel I.

2005-01-01

Background: Hypothermia may be an effective treatment for stroke or acute myocardial infarction; however, it provokes vigorous shivering, which causes potentially dangerous hemodynamic responses and prevents further hypothermia. Magnesium is an attractive antishivering agent because it is used for treatment of postoperative shivering and provides protection against ischemic injury in animal models. We tested the hypothesis that magnesium reduces the threshold (triggering core temperature) and gain of shivering without substantial sedation or muscle weakness. Methods: We studied nine healthy male volunteers (18-40 yr) on two randomly assigned treatment days: 1) Control and 2) Magnesium (80 mg·kg-1 followed by infusion at 2 g·h-1). Lactated Ringer's solution (4°C) was infused via a central venous catheter over a period of approximately 2 hours to decrease tympanic membrane temperature ≈1.5°C·h-1. A significant and persistent increase in oxygen consumption identified the threshold. The gain of shivering was determined by the slope of oxygen consumption vs. core temperature regression. Sedation was evaluated using verbal rating score (VRS, 0-10) and bispectral index of the EEG (BIS). Peripheral muscle strength was evaluated using dynamometry and spirometry. Data were analyzed using repeated-measures ANOVA; P<0.05 was statistically significant. Results: Magnesium reduced the shivering threshold (36.3±0.4 [mean±SD] vs. 36.6±0.3°C, P=0.040). It did not affect the gain of shivering (Control: 437±289, Magnesium: 573±370 ml·min-1·°C-1, P=0.344). The magnesium bolus did not produce significant sedation or appreciably reduce muscle strength. Conclusions: Magnesium significantly reduced the shivering threshold; however, due to the modest absolute reduction, this finding is considered to be clinically unimportant for induction of therapeutic hypothermia. PMID:15749735

[Protective effect of Uncaria rhynchophylla total alkaloids pretreatment on hippocampal neurons after acute hypoxia].

PubMed

Liu, Wei; Zhang, Zhao-qin; Zhao, Xiao-min; Gao, Yun-sheng

2006-05-01

To investigate the effect of Uncaria rhynchophylla total alkaloids (RTA) pretreatment on the voltage-gated sodium currents of the rat hippocampal neurons after acute hypoxia. Primary cultured hippocampal neurons were divided into RTA pre-treated and non-pretreated groups. Patch clamp whole-cell recording was used to compare the voltage-gated sodium current amplitude and threshold with those before hypoxia. After acute hypoxia, sodium current amplitude was significantly decreased and its threshold was upside. RTA pretreatment could inhibit the reduction of sodium current amplitude. RTA pretreatment alleviates the acute hypoxia-induced change of sodium currents, which may be one of the mechanisms for protective effect of RTA on cells.

Effects of transcranial direct current stimulation of primary somatosensory cortex on vibrotactile detection and discrimination

PubMed Central

Labbé, Sara; Meftah, El-Mehdi

2016-01-01

Anodal transcranial direct current stimulation (a-tDCS) of primary somatosensory cortex (S1) has been shown to enhance tactile spatial acuity, but there is little information as to the underlying neuronal mechanisms. We examined vibrotactile perception on the distal phalanx of the middle finger before, during, and after contralateral S1 tDCS [a-, cathodal (c)-, and sham (s)-tDCS]. The experiments tested our shift-gain hypothesis, which predicted that a-tDCS would decrease vibrotactile detection and discrimination thresholds (leftward shift of the stimulus-response function with increased gain/slope) relative to s-tDCS, whereas c-tDCS would have the opposite effects (relative to s-tDCS). The results showed that weak a-tDCS (1 mA, 20 min) led to a reduction in both vibrotactile detection and discrimination thresholds to 73–76% of baseline during the application of the stimulation in subjects categorized as responders. These effects persisted after the end of a-tDCS but were absent 30 min later. Most, but not all, subjects showed a decrease in threshold (8/12 for detection; 9/12 for discrimination). Intersubject variability was explained by a ceiling effect in the discrimination task. c-tDCS had no significant effect on either detection or discrimination threshold. Taken together, our results supported our shift-gain hypothesis for a-tDCS but not c-tDCS. PMID:26864757

Follow-up of hearing thresholds among forge hammering workers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kamal, A.A.; Mikael, R.A.; Faris, R.

Hearing threshold was reexamined in a group of forge hammering workers investigated 8 years ago with consideration of the age effect and of auditory symptoms. Workers were exposed to impact noise that ranged from 112 to 139 dB(A)--at an irregular rate of 20 to 50 drop/minute--and a continuous background noise that ranged from 90 to 94 dB(A). Similar to what was observed 8 years ago, the present permanent threshold shift (PTS) showed a maximum notch at the frequency of 6 kHz and considerable elevations at the frequencies of 0.25-1 kHz. The age-corrected PTS and the postexposure hearing threshold were significantlymore » higher than the corresponding previous values at the frequencies 0.25, 0.5, 1, and 8 kHz only. The rise was more evident at the low than at the high frequencies. Temporary threshold shift (TTS) values were significantly less than those 8 years ago. Contrary to the previous TTS, the present TTS were higher at low than at high frequencies. Although progression of PTS at the frequencies 0.25 and 0.5 kHz was continuous throughout the observed durations of exposure, progression at higher frequencies occurred essentially in the first 10 to 15 years of exposure. Thereafter, it followed a much slower rate. Tinnitus was significantly associated with difficulty in hearing the human voice and with elevation of PTS at all the tested frequencies, while acoustic after-image was significantly associated with increment of PTS at the frequencies 0.25-2 kHz. No relation between PTS and smoking was found. PTS at low frequencies may provide an indication of progression of hearing damage when the sensitivity at 6 and 4 kHz diminishes after prolonged years of exposure. Tinnitus and acoustic after-image are related to the auditory effect of forge hammering noise.« less

Auditory-nerve single-neuron thresholds to electrical stimulation from scala tympani electrodes.

PubMed

Parkins, C W; Colombo, J

1987-12-31

Single auditory-nerve neuron thresholds were studied in sensory-deafened squirrel monkeys to determine the effects of electrical stimulus shape and frequency on single-neuron thresholds. Frequency was separated into its components, pulse width and pulse rate, which were analyzed separately. Square and sinusoidal pulse shapes were compared. There were no or questionably significant threshold differences in charge per phase between sinusoidal and square pulses of the same pulse width. There was a small (less than 0.5 dB) but significant threshold advantage for 200 microseconds/phase pulses delivered at low pulse rates (156 pps) compared to higher pulse rates (625 pps and 2500 pps). Pulse width was demonstrated to be the prime determinant of single-neuron threshold, resulting in strength-duration curves similar to other mammalian myelinated neurons, but with longer chronaxies. The most efficient electrical stimulus pulse width to use for cochlear implant stimulation was determined to be 100 microseconds/phase. This pulse width delivers the lowest charge/phase at threshold. The single-neuron strength-duration curves were compared to strength-duration curves of a computer model based on the specific anatomy of auditory-nerve neurons. The membrane capacitance and resulting chronaxie of the model can be varied by altering the length of the unmyelinated termination of the neuron, representing the unmyelinated portion of the neuron between the habenula perforata and the hair cell. This unmyelinated segment of the auditory-nerve neuron may be subject to aminoglycoside damage. Simulating a 10 micron unmyelinated termination for this model neuron produces a strength-duration curve that closely fits the single-neuron data obtained from aminoglycoside deafened animals. Both the model and the single-neuron strength-duration curves differ significantly from behavioral threshold data obtained from monkeys and humans with cochlear implants. This discrepancy can best be explained by the involvement of higher level neurologic processes in the behavioral responses. These findings suggest that the basic principles of neural membrane function must be considered in developing or analyzing electrical stimulation strategies for cochlear prostheses if the appropriate stimulation of frequency specific populations of auditory-nerve neurons is the objective.

Organic field-effect transistor with octadecyltrichlorosilane (OTS) self-assembled monolayers on gate oxide: effect of OTS quality

NASA Astrophysics Data System (ADS)

Devynck, M.; Tardy, P.; Wantz, G.; Nicolas, Y.; Hirsch, L.

2011-12-01

The effect of OTS (octadecyltrichlorosilane) Self-Assembled Monolayer (SAM) grafted on SiO2 gate dielectric of pentacene-based OFETs (organic field-effect transistors) is investigated. A significant improvement of the charge mobility (μ), up to 0.74 cm2/V s, is reached thanks to OTS treatment. However, in spite of improved performances, several drawbacks, such as an increase in mobility dispersion, substantial hysteresis in IDS-VG characteristics and high threshold voltages (VT), are observed. Changing solvent and deposition method turns out to have no significant effect on the mobility dispersion. A more accurate approach on the evolution of the mobility and the threshold voltage dispersion with OTS storage time highlights the effect of the OTS solution aging. Even if no difference is evidenced in the surface energy and roughness of the OTS layer, electrical characteristics exhibit considerable deterioration with OTS solution storage time. Using an "aged" OTS solution, opened under air, kept under argon and distilled before use, results in an increase of the IDS-VG hysteresis as well as in VT and in mobility dispersion. In comparison, fresh-OTS-based OFETs present a very low hysteresis, a threshold voltage close to 0 and a much lower mobility dispersion. It is demonstrated that aged OTS solutions contain impurities that are not removed by distillation process, which leads to a less densely packed layer causing interfacial charge traps thus deteriorated performances.

Transtympanic injections of N-acetylcysteine for the prevention of cisplatin-induced ototoxicity: a feasible method with promising efficacy.

PubMed

Riga, Maria G; Chelis, Leonidas; Kakolyris, Stylianos; Papadopoulos, Stergios; Stathakidou, Sofia; Chamalidou, Eleni; Xenidis, Nikolaos; Amarantidis, Kyriakos; Dimopoulos, Prokopios; Danielides, Vasilios

2013-02-01

Ototoxicity is a common and irreversible adverse effect of cisplatin treatment with great impact on the patients' quality of life. N-acetylcysteine is a low-molecular-weight agent which has shown substantial otoprotective activity. The role of transtympanic infusions of N-acetylcysteine was examined in a cohort of patients treated with cisplatin-based regimens. Twenty cisplatin-treated patients were subjected, under local anesthesia, to transtympanic N-acetylcysteine (10%) infusions in 1 ear, during the hydration procedure preceding intravenous effusion of cisplatin. The contralateral ear was used as control. The number of transtympanic infusions was respective to the number of administered cycles. Hearing acuity was evaluated before each cycle with pure tone audiometry by an audiologist blinded to the treated ear. A total of 84 transtympanic infusions were performed. In treated ears, no significant changes in auditory thresholds were recorded. In the control ears cisplatin induced a significant decrease of auditory thresholds at the 8000 Hz frequency band (P=0.008). At the same frequency (8000 Hz), the changes in auditory thresholds were significantly larger for the control ears than the treated ones (P=0.005). An acute pain starting shortly after the injection and lasting for a few minutes seemed to be the only significant adverse effect. Transtympanic injections of N-acetylcysteine seem to be a feasible and effective otoprotective strategy for the prevention of cisplatin-induced ototoxicity. Additional studies are required to further clarify the efficiency of this treatment and determine the optimal dosage and protocol.

Contralateral Occlusion Test: The effect of external ear canal occlusion on hearing thresholds.

PubMed

Reis, Luis Roque; Fernandes, Paulo; Escada, Pedro

Bedside testing with tuning forks may decrease turnaround time and improve decision making for a quick qualitative assessment of hearing loss. The purpose of this study was to quantify the effects of ear canal occlusion on hearing, in order to decide which tuning fork frequency is more appropriate to use for quantifying hearing loss with the Contralateral Occlusion Test. Twenty normal-hearing adults (forty ears) underwent sound field pure tone audiometry with and without ear canal occlusion. Each ear was tested with the standard frequencies. The contralateral ear was suppressed with by masking. Ear occlusion was performed by two examiners. Participants aged between 21 and 30 years (25.6±3.03 years) showed an increase in hearing thresholds with increasing frequencies from 19.94dB (250Hz) to 39.25dB (2000Hz). The threshold difference between occluded and unoccluded conditions was statistically significant and increased from 10.69dB (250Hz) to 32.12dB (2000Hz). There were no statistically significant differences according to gender or between the examiners. The occlusion effect increased the hearing thresholds and became more evident with higher frequencies. The occlusion method as performed demonstrated reproducibility. In the Contralateral Occlusion Test, 256Hz or 512Hz tuning forks should be used for diagnosis of mild hearing loss, and a 2048Hz tuning fork should be used for moderate hearing loss. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

Joint Mobilization Enhances Mechanisms of Conditioned Pain Modulation in Individuals With Osteoarthritis of the Knee.

PubMed

Courtney, Carol A; Steffen, Alana D; Fernández-de-Las-Peñas, César; Kim, John; Chmell, Samuel J

2016-03-01

An experimental laboratory study with a repeated-measures crossover design. Treatment effects of joint mobilization may occur in part by decreasing excitability of central nociceptive pathways. Impaired conditioned pain modulation (CPM) has been found experimentally in persons with knee and hip osteoarthritis, indicating impaired inhibition of central nociceptive pathways. We hypothesized increased effectiveness of CPM following application of joint mobilization, determined via measures of deep tissue hyperalgesia. To examine the effect of joint mobilization on impaired CPM. An examination of 40 individuals with moderate/severe knee osteoarthritis identified 29 (73%) with impaired CPM. The subjects were randomized to receive 6 minutes of knee joint mobilization (intervention) or manual cutaneous input only, 1 week apart. Deep tissue hyperalgesia was examined via pressure pain thresholds bilaterally at the knee medial joint line and the hand at baseline, postintervention, and post-CPM testing. Further, vibration perception threshold was measured at the medial knee epicondyle at baseline and post-CPM testing. Joint mobilization, but not cutaneous input intervention, resulted in a global increase in pressure pain threshold, indicated by diminished hyperalgesic responses to pressure stimulus. Further, CPM was significantly enhanced following joint mobilization. Diminished baseline vibration perception threshold acuity was enhanced following joint mobilization at the knee that received intervention, but not at the contralateral knee. Resting pain was also significantly lower following the joint intervention. Conditioned pain modulation was enhanced following joint mobilization, demonstrated by a global decrease in deep tissue pressure sensitivity. Joint mobilization may act via enhancement of descending pain mechanisms in patients with painful knee osteoarthritis.

Cost-effectiveness thresholds in health care: a bookshelf guide to their meaning and use.

PubMed

Culyer, Anthony J

2016-10-01

There is misunderstanding about both the meaning and the role of cost-effectiveness thresholds in policy decision making. This article dissects the main issues by use of a bookshelf metaphor. Its main conclusions are as follows: it must be possible to compare interventions in terms of their impact on a common measure of health; mere effectiveness is not a persuasive case for inclusion in public insurance plans; public health advocates need to address issues of relative effectiveness; a 'first best' benchmark or threshold ratio of health gain to expenditure identifies the least effective intervention that should be included in a public insurance plan; the reciprocal of this ratio - the 'first best' cost-effectiveness threshold - will rise or fall as the health budget rises or falls (ceteris paribus); setting thresholds too high or too low costs lives; failure to set any cost-effectiveness threshold at all also involves avertable deaths and morbidity; the threshold cannot be set independently of the health budget; the threshold can be approached from either the demand side or the supply side - the two are equivalent only in a health-maximising equilibrium; the supply-side approach generates an estimate of a 'second best' cost-effectiveness threshold that is higher than the 'first best'; the second best threshold is the one generally to be preferred in decisions about adding or subtracting interventions in an established public insurance package; multiple thresholds are implied by systems having distinct and separable health budgets; disinvestment involves eliminating effective technologies from the insured bundle; differential weighting of beneficiaries' health gains may affect the threshold; anonymity and identity are factors that may affect the interpretation of the threshold; the true opportunity cost of health care in a community, where the effectiveness of interventions is determined by their impact on health, is not to be measured in money - but in health itself.

Antipyretic effect of ibuprofen in Gabonese children with uncomplicated falciparum malaria: a randomized, double-blind, placebo-controlled trial

PubMed Central

Matsiégui, Pierre-Blaise; Missinou, Michel A; Necek, Magdalena; Mavoungou, Elie; Issifou, Saadou; Lell, Bertrand; Kremsner, Peter G

2008-01-01

Background Antipyretic drugs are widely used in children with fever, though there is a controversy about the benefit of reducing fever in children with malaria. In order to assess the effect of ibuprofen on fever compared to placebo in children with uncomplicated Plasmodium falciparum malaria in Gabon, a randomized double blind placebo controlled trial, was designed. Methods Fifty children between two and seven years of age with uncomplicated malaria were included in the study. For the treatment of fever, all patients "received" mechanical treatment when the temperature rose above 37.5°C. In addition to the mechanical treatment, continuous fanning and cooling blanket, patients were assigned randomly to receive ibuprofen (7 mg/kg body weight, every eight hours) or placebo. Results The fever clearance time using a fever threshold of 37.5°C was similar in children receiving ibuprofen compared to those receiving placebo. The difference was also not statistically significant using a fever threshold of 37.8°C or 38.0°C. However, the fever time and the area under the fever curve were significantly smaller in the ibuprofen group compared to the placebo group. Conclusion Ibuprofen is effective in reducing the time with fever. The effect on fever clearance is less obvious and depends on definition of the fever threshold. Trial registration The trial registration number is: NCT00167713 PMID:18503714

Central or Peripheral Delivery of an Adenosine A1 Receptor Agonist Improves Mechanical Allodynia in a Mouse Model of Painful Diabetic Neuropathy

PubMed Central

Katz, N. K.; Ryals, J. M.; Wright, D. E.

2014-01-01

Diabetic peripheral neuropathy is a common complication of diabetes mellitus, and a significant proportion of individuals suffer debilitating pain that significantly affects their quality of life. Unfortunately, symptomatic treatment options have limited efficacy, and often carry significant risk of systemic adverse effects. Activation of the adenosine A1 receptor (A1R) by the analgesic small molecule adenosine has been shown to have antinociceptive benefits in models of inflammatory and neuropathic pain. The current study used a mouse model of painful diabetic neuropathy to determine the effect of diabetes on endogenous adenosine production, and if central or peripheral delivery of adenosine receptor agonists could alleviate signs of mechanical allodynia in diabetic mice. Diabetes was induced using streptozocin in male A/J mice. Mechanical withdrawal thresholds were measured weekly to characterize neuropathy phenotype. Hydrolysis of AMP into adenosine by ectonucleotidases was determined in the dorsal root ganglia (DRG) and spinal cord at 8-weeks post-induction of diabetes. AMP, adenosine and the specific A1R agonist, N6-cyclopentyladenosine (CPA), were administered both centrally (intrathecal) and peripherally (intraplantar) to determine the effect of activation of adenosine receptors on mechanical allodynia in diabetic mice. Eight weeks post-induction, diabetic mice displayed significantly decreased hydrolysis of extracellular AMP in the DRG; at this same time, diabetic mice displayed significantly decreased mechanical withdrawal thresholds compared to nondiabetic controls. Central delivery AMP, adenosine and CPA significantly improved mechanical withdrawal thresholds in diabetic mice. Surprisingly, peripheral delivery of CPA also improved mechanical allodynia in diabetic mice. This study provides new evidence that diabetes significantly affects endogenous AMP hydrolysis, suggesting that altered adenosine production could contribute to the development of painful diabetic neuropathy. Moreover, central and peripheral activation of A1R significantly improved mechanical sensitivity, warranting further investigation into this important antinociceptive pathway as a novel therapeutic option for the treatment of painful diabetic neuropathy. PMID:25451280

Optimal control of population recovery--the role of economic restoration threshold.

PubMed

Lampert, Adam; Hastings, Alan

2014-01-01

A variety of ecological systems around the world have been damaged in recent years, either by natural factors such as invasive species, storms and global change or by direct human activities such as overfishing and water pollution. Restoration of these systems to provide ecosystem services entails significant economic benefits. Thus, choosing how and when to restore in an optimal fashion is important, but has not been well studied. Here we examine a general model where population growth can be induced or accelerated by investing in active restoration. We show that the most cost-effective method to restore an ecosystem dictates investment until the population approaches an 'economic restoration threshold', a density above which the ecosystem should be left to recover naturally. Therefore, determining this threshold is a key general approach for guiding efficient restoration management, and we demonstrate how to calculate this threshold for both deterministic and stochastic ecosystems. © 2013 John Wiley & Sons Ltd/CNRS.

Effects of ozone therapy on facial nerve regeneration.

PubMed

Ozbay, Isa; Ital, Ilker; Kucur, Cuneyt; Akcılar, Raziye; Deger, Aysenur; Aktas, Savas; Oghan, Fatih

Ozone may promote moderate oxidative stress, which increases antioxidant endogenous systems. There are a number of antioxidants that have been investigated therapeutically for improving peripheral nerve regeneration. However, no previous studies have reported the effect of ozone therapy on facial nerve regeneration. We aimed to evaluate the effect of ozone therapy on facial nerve regeneration. Fourteen Wistar albino rats were randomly divided into two groups with experimental nerve crush injuries: a control group, which received saline treatment post-crush, and an experimental group, which received ozone treatment. All animals underwent surgery in which the left facial nerve was exposed and crushed. Treatment with saline or ozone began on the day of the nerve crush. Left facial nerve stimulation thresholds were measured before crush, immediately after crush, and after 30 days. After measuring nerve stimulation thresholds at 30 days post-injury, the crushed facial nerve was excised. All specimens were studied using light and electron microscopy. Post-crushing, the ozone-treated group had lower stimulation thresholds than the saline group. Although this did not achieve statistical significance, it is indicative of greater functional improvement in the ozone group. Significant differences were found in vascular congestion, macrovacuolization, and myelin thickness between the ozone and control groups. Significant differences were also found in axonal degeneration and myelin ultrastructure between the two groups. We found that ozone therapy exerted beneficial effect on the regeneration of crushed facial nerves in rats. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Systematic study of the effects of stimulus parameters and stimulus location on afterdischarges elicited by electrical stimulation in the rat.

PubMed

Shigeto, Hiroshi; Boongird, Atthaporn; Baker, Kenneth; Kellinghaus, Christoph; Najm, Imad; Lüders, Hans

2013-03-01

Electrical brain stimulation is used in a variety of clinical situations, including cortical mapping for epilepsy surgery, cortical stimulation therapy to terminate seizure activity in the cortex, and in deep brain stimulation therapy. However, the effects of stimulus parameters are not fully understood. In this study, we systematically tested the impact of various stimulation parameters on the generation of motor symptoms and afterdischarges (ADs). Focal electrical stimulation was delivered at subdural cortical, intracortical, and hippocampal sites in a rat model. The effects of stimulus parameter on the generation of motor symptoms and on the occurrence of ADs were examined. The effect of stimulus irregularity was tested using random or regular 50Hz stimulation through subdural electrodes. Hippocampal stimulation produced ADs at lower thresholds than neocortical stimulation. Hippocampal stimulation also produced significantly longer ADs. Both in hippocampal and cortical stimulation, when the total current was kept constant with changing pulse width, the threshold for motor symptom or AD was lowest between 50 and 100Hz and higher at both low and high frequencies. However, if the pulse width was fixed, the threshold did not increase above 100Hz and it apparently continued to decrease through 800Hz even if the difference did not reach statistical significance. There was no significant difference between random and regular stimulation. Overall, these results indicate that electrode location and several stimulus parameters including frequency, pulse width, and total electricity are important in electrical stimulation to produce motor symptoms and ADs. Copyright © 2012 Elsevier B.V. All rights reserved.

Acoustic Reflex Testing in Neonatal Hearing Screening and Subsequent Audiological Evaluation.

PubMed

Jacob-Corteletti, Lilian Cássia Bórnia; Araújo, Eliene Silva; Duarte, Josilene Luciene; Zucki, Fernanda; Alvarenga, Kátia de Freitas

2018-06-18

The aims of the study were to examine the acoustic reflex screening and threshold in healthy neonates and those at risk of hearing loss and to determine the effect of birth weight and gestational age on acoustic stapedial reflex (ASR). We assessed 18 healthy neonates (Group I) and 16 with at least 1 risk factor for hearing loss (Group II); all of them passed the transient evoked otoacoustic emission test that assessed neonatal hearing. The test battery included an acoustic reflex screening with activators of 0.5, 1, 2, and 4 kHz and broadband noise and an acoustic reflex threshold test with all of them, except for the broadband noise activator. In the evaluated neonates, the main risk factors were the gestational age at birth and a low birth weight; hence, these were further analyzed. The lower the gestational age at birth and birth weight, the less likely that an acoustic reflex would be elicited by pure-tone activators. This effect was significant at the frequencies of 0.5, 1, and 2 kHz for gestational age at birth and at the frequencies of 1 and 2 kHz for birth weight. When the broadband noise stimulus was used, a response was elicited in all neonates in both groups. When the pure-tone stimulus was used, the Group II showed the highest acoustic reflex thresholds and the highest percentage of cases with an absent ASR. The ASR threshold varied from 50 to 100 dB HL in both groups. Group II presented higher mean ASR thresholds than Group I, this difference being significant at frequencies of 1, 2, and 4 kHz. Birth weight and gestational age at birth were related to the elicitation of the acoustic reflex. Neonates with these risk factors for hearing impairment were less likely to exhibit the acoustic reflex and had higher thresholds.

Effect of Tadalafil on Seizure Threshold and Activity of Antiepileptic Drugs in Three Acute Seizure Tests in Mice.

PubMed

Socała, Katarzyna; Nieoczym, Dorota; Pieróg, Mateusz; Wyska, Elżbieta; Szafarz, Małgorzata; Doboszewska, Urszula; Wlaź, Piotr

2018-02-09

Tadalafil, a selective phosphodiesterase type 5 inhibitor, is a long-acting oral agent for the treatment of erectile dysfunction of multiple etiologies. Although generalized tonic-clonic seizures were reported in a healthy man after taking tadalafil, the influence of tadalafil on seizure susceptibility has not been studied so far. Therefore, the aim of the present study was to investigate the effect of tadalafil on seizure threshold as well as on the activity of some first- and second-generation antiepileptic drugs in three acute seizure tests in mice. The obtained results showed that tadalafil, at the highest dose tested (20 mg/kg), significantly decreased the threshold for the first myoclonic twitch in the intravenous pentylenetetrazole (i.v. PTZ) seizure test. It did not affect the threshold for generalized clonic seizure and forelimb tonus in the i.v. PTZ, for tonic hindlimb extension in the maximal electroshock seizure threshold test, and for psychomotor seizure in the 6-Hz-induced seizure threshold test. Tadalafil did not alter the anticonvulsant activity of any of the studied antiepileptic drugs in electrically induced seizure tests. Interestingly, tadalafil potentiated the anticonvulsant activity of clonazepam and decreased the anticonvulsant activity of oxcarbazepine in the i.v. PTZ test. These interactions were pharmacodynamic in nature, as tadalafil did not alter clonazepam and oxcarbazepine concentrations both in serum and brain tissue. Furthermore, neither tadalafil alone nor its combinations with the studied antiepileptic drugs produced any significant impairment of motor coordination (assessed in the chimney test), muscular strength (investigated in the grip-strength test), and long-term memory (assessed in the passive avoidance task). In conclusion, tadalafil may increase the risk of myoclonic seizure and decrease the anticonvulsant efficacy of oxcarbazepine. Further studies are warranted to evaluate the safety of tadalafil usage in patients with epilepsy.

Acute effect of ozone exposure on daily mortality in seven cities of Jiangsu Province, China: No clear evidence for threshold.

PubMed

Chen, Kai; Zhou, Lian; Chen, Xiaodong; Bi, Jun; Kinney, Patrick L

2017-05-01

Few multicity studies have addressed the health effects of ozone in China due to the scarcity of ozone monitoring data. A critical scientific and policy-relevant question is whether a threshold exists in the ozone-mortality relationship. Using a generalized additive model and a univariate random-effects meta-analysis, this research evaluated the relationship between short-term ozone exposure and daily total mortality in seven cities of Jiangsu Province, China during 2013-2014. Spline, subset, and threshold models were applied to further evaluate whether a safe threshold level exists. This study found strong evidence that short-term ozone exposure is significantly associated with premature total mortality. A 10μg/m 3 increase in the average of the current and previous days' maximum 8-h average ozone concentration was associated with a 0.55% (95% posterior interval: 0.34%, 0.76%) increase of total mortality. This finding is robust when considering the confounding effect of PM 2.5 , PM 10 , NO 2 , and SO 2 . No consistent evidence was found for a threshold in the ozone-mortality concentration-response relationship down to concentrations well below the current Chinese Ambient Air Quality Standard (CAAQS) level 2 standard (160μg/m 3 ). Our findings suggest that ozone concentrations below the current CAAQS level 2 standard could still induce increased mortality risks in Jiangsu Province, China. Continuous air pollution control measures could yield important health benefits in Jiangsu Province, China, even in cities that meet the current CAAQS level 2 standard. Copyright © 2017 Elsevier Inc. All rights reserved.

Acute effect of ozone exposure on daily mortality in seven cities of Jiangsu Province, China: No clear evidence for threshold

PubMed Central

Chen, Kai; Zhou, Lian; Chen, Xiaodong; Bi, Jun; Kinney, Patrick L.

2017-01-01

Background Few multicity studies have addressed the health effects of ozone in China due to the scarcity of ozone monitoring data. A critical scientific and policy-relevant question is whether a threshold exists in the ozone-mortality relationship. Methods Using a generalized additive model and a univariate random-effects meta-analysis, this research evaluated the relationship between short-term ozone exposure and daily total mortality in seven cities of Jiangsu Province, China during 2013–2014. Spline, subset, and threshold models were applied to further evaluate whether a safe threshold level exists. Results This study found strong evidence that short-term ozone exposure is significantly associated with premature total mortality. A 10 μg/m3 increase in the average of the current and previous days’ maximum 8-h average ozone concentration was associated with a 0.55% (95% posterior interval: 0.34%, 0.76%) increase of total mortality. This finding is robust when considering the confounding effect of PM2.5, PM10, NO2, and SO2. No consistent evidence was found for a threshold in the ozone-mortality concentration-response relationship down to concentrations well below the current Chinese Ambient Air Quality Standard (CAAQS) level 2 standard (160 μg/m3). Conclusions Our findings suggest that ozone concentrations below the current CAAQS level 2 standard could still induce increased mortality risks in Jiangsu Province, China. Continuous air pollution control measures could yield important health benefits in Jiangsu Province, China, even in cities that meet the current CAAQS level 2 standard. PMID:28231551

Evaluation of the pentylenetetrazole seizure threshold test in epileptic mice as surrogate model for drug testing against pharmacoresistant seizures.

PubMed

Töllner, Kathrin; Twele, Friederike; Löscher, Wolfgang

2016-04-01

Resistance to antiepileptic drugs (AEDs) is a major problem in epilepsy therapy, so that development of more effective AEDs is an unmet clinical need. Several rat and mouse models of epilepsy with spontaneous difficult-to-treat seizures exist, but because testing of antiseizure drug efficacy is extremely laborious in such models, they are only rarely used in the development of novel AEDs. Recently, the use of acute seizure tests in epileptic rats or mice has been proposed as a novel strategy for evaluating novel AEDs for increased antiseizure efficacy. In the present study, we compared the effects of five AEDs (valproate, phenobarbital, diazepam, lamotrigine, levetiracetam) on the pentylenetetrazole (PTZ) seizure threshold in mice that were made epileptic by pilocarpine. Experiments were started 6 weeks after a pilocarpine-induced status epilepticus. At this time, control seizure threshold was significantly lower in epileptic than in nonepileptic animals. Unexpectedly, only one AED (valproate) was less effective to increase seizure threshold in epileptic vs. nonepileptic mice, and this difference was restricted to doses of 200 and 300 mg/kg, whereas the difference disappeared at 400mg/kg. All other AEDs exerted similar seizure threshold increases in epileptic and nonepileptic mice. Thus, induction of acute seizures with PTZ in mice pretreated with pilocarpine does not provide an effective and valuable surrogate method to screen drugs for antiseizure efficacy in a model of difficult-to-treat chronic epilepsy as previously suggested from experiments with this approach in rats. Copyright © 2016 Elsevier Inc. All rights reserved.

The treatment effect of hamstring stretching and nerve mobilization for patients with radicular lower back pain

PubMed Central

Lee, Ju-hyun; Kim, Tae-ho

2017-01-01

[Purpose] In this paper, hamstring stretching and nerve mobilization are conducted on patients with radicular lower back pain, and changes to pain levels, pressure thresholds, angles of knee joint extension, and disorder levels of lower back pain were studied. [Subjects and Methods] The subjects were divided into two groups: one group conducted hamstring stretches and was comprised of 6 male and 5 female subjects, and the other group received nerve mobilization treatment and was comprised of 5 male and 6 female subjects. [Results] Pain level and the disorder index of lower back pain were significantly alleviated after the intervention in both groups. Pressure threshold and angles of knee extension were significantly increased after the intervention in both groups. Comparing the two groups, the alleviation of pain was more significant in the nerve mobilization group. [Conclusion] Patients with radicular lower back pain showed significant differences in pain level, pressure threshold, knee extension angle, and disorder index of lower back pain for both the hamstring stretching group and nerve mobilization group after the treatment. Hamstring stretching and nerve mobilization can be usefully applied for the therapy of patients with radicular lower back pain. PMID:28931991

A critique of the use of indicator-species scores for identifying thresholds in species responses

USGS Publications Warehouse

Cuffney, Thomas F.; Qian, Song S.

2013-01-01

Identification of ecological thresholds is important both for theoretical and applied ecology. Recently, Baker and King (2010, King and Baker 2010) proposed a method, threshold indicator analysis (TITAN), to calculate species and community thresholds based on indicator species scores adapted from Dufrêne and Legendre (1997). We tested the ability of TITAN to detect thresholds using models with (broken-stick, disjointed broken-stick, dose-response, step-function, Gaussian) and without (linear) definitive thresholds. TITAN accurately and consistently detected thresholds in step-function models, but not in models characterized by abrupt changes in response slopes or response direction. Threshold detection in TITAN was very sensitive to the distribution of 0 values, which caused TITAN to identify thresholds associated with relatively small differences in the distribution of 0 values while ignoring thresholds associated with large changes in abundance. Threshold identification and tests of statistical significance were based on the same data permutations resulting in inflated estimates of statistical significance. Application of bootstrapping to the split-point problem that underlies TITAN led to underestimates of the confidence intervals of thresholds. Bias in the derivation of the z-scores used to identify TITAN thresholds and skewedness in the distribution of data along the gradient produced TITAN thresholds that were much more similar than the actual thresholds. This tendency may account for the synchronicity of thresholds reported in TITAN analyses. The thresholds identified by TITAN represented disparate characteristics of species responses that, when coupled with the inability of TITAN to identify thresholds accurately and consistently, does not support the aggregation of individual species thresholds into a community threshold.

Lubiprostone does not Influence Visceral Pain Thresholds in Patients with Irritable Bowel Syndrome

PubMed Central

Whitehead, William E.; Palsson, Olafur S.; Gangarosa, Lisa; Turner, Marsha; Tucker, Jane

2011-01-01

Background In clinical trials, lubiprostone reduced the severity of abdominal pain. Aims The primary aim was to determine whether lubiprostone raises the threshold for abdominal pain induced by intraluminal balloon distention. A secondary aim was to determine whether changes in pain sensitivity influence clinical pain independently of changes in transit time. Methods Sixty-two patients with irritable bowel syndrome with constipation (IBS-C) participated in an 8-week crossover study. All subjects completed a 14-day baseline ending with a barostat test of pain and urge sensory thresholds. Half, randomly selected, then received 48 ug/day of lubiprostone for 14 days ending with a pain sensitivity test and a Sitzmark test of transit time. This was followed by a 14-day washout and then a crossover to 14 days of placebo with tests of pain sensitivity and transit time. The other half of the subjects received placebo before lubiprostone. All kept symptom diaries. Results Stools were significantly softer when taking lubiprostone compared to placebo (Bristol Stool scores 4.20 vs. 3.44, p<0.001). However, thresholds for pain (17.36 vs. 17.83 mmHg, lubiprostone vs. placebo) and urgency to defecate (14.14 vs. 14.53 mmHg) were not affected by lubiprostone. Transit time was not significantly different between lubiprostone and placebo (51.27 vs. 51.81 hours), and neither pain sensitivity nor transit time was a significant predictor of clinical pain. Conclusions Lubiprostone has no effect on visceral sensory thresholds. The reductions in clinical pain that occur while taking lubiprostone appear to be secondary to changes in stool consistency. PMID:21914041

Low-frequency acoustic pressure, velocity, and intensity thresholds in a bottlenose dolphin (Tursiops truncatus) and white whale (Delphinapterus leucas)

NASA Astrophysics Data System (ADS)

Finneran, James J.; Carder, Donald A.; Ridgway, Sam H.

2002-01-01

The relative contributions of acoustic pressure and particle velocity to the low-frequency, underwater hearing abilities of the bottlenose dolphin (Tursiops truncatus) and white whale (Delphinapterus leucas) were investigated by measuring (masked) hearing thresholds while manipulating the relationship between the pressure and velocity. This was accomplished by varying the distance within the near field of a single underwater sound projector (experiment I) and using two underwater sound projectors and an active sound control system (experiment II). The results of experiment I showed no significant change in pressure thresholds as the distance between the subject and the sound source was changed. In contrast, velocity thresholds tended to increase and intensity thresholds tended to decrease as the source distance decreased. These data suggest that acoustic pressure is a better indicator of threshold, compared to particle velocity or mean active intensity, in the subjects tested. Interpretation of the results of experiment II (the active sound control system) was difficult because of complex acoustic conditions and the unknown effects of the subject on the generated acoustic field; however, these data also tend to support the results of experiment I and suggest that odontocete thresholds should be reported in units of acoustic pressure, rather than intensity.

A multi-SNP association test for complex diseases incorporating an optimal P-value threshold algorithm in nuclear families.

PubMed

Wang, Yi-Ting; Sung, Pei-Yuan; Lin, Peng-Lin; Yu, Ya-Wen; Chung, Ren-Hua

2015-05-15

Genome-wide association studies (GWAS) have become a common approach to identifying single nucleotide polymorphisms (SNPs) associated with complex diseases. As complex diseases are caused by the joint effects of multiple genes, while the effect of individual gene or SNP is modest, a method considering the joint effects of multiple SNPs can be more powerful than testing individual SNPs. The multi-SNP analysis aims to test association based on a SNP set, usually defined based on biological knowledge such as gene or pathway, which may contain only a portion of SNPs with effects on the disease. Therefore, a challenge for the multi-SNP analysis is how to effectively select a subset of SNPs with promising association signals from the SNP set. We developed the Optimal P-value Threshold Pedigree Disequilibrium Test (OPTPDT). The OPTPDT uses general nuclear families. A variable p-value threshold algorithm is used to determine an optimal p-value threshold for selecting a subset of SNPs. A permutation procedure is used to assess the significance of the test. We used simulations to verify that the OPTPDT has correct type I error rates. Our power studies showed that the OPTPDT can be more powerful than the set-based test in PLINK, the multi-SNP FBAT test, and the p-value based test GATES. We applied the OPTPDT to a family-based autism GWAS dataset for gene-based association analysis and identified MACROD2-AS1 with genome-wide significance (p-value=2.5×10(-6)). Our simulation results suggested that the OPTPDT is a valid and powerful test. The OPTPDT will be helpful for gene-based or pathway association analysis. The method is ideal for the secondary analysis of existing GWAS datasets, which may identify a set of SNPs with joint effects on the disease.

Threshold Evaluation of Emergency Risk Communication for Health Risks Related to Hazardous Ambient Temperature.

PubMed

Liu, Yang; Hoppe, Brenda O; Convertino, Matteo

2018-04-10

Emergency risk communication (ERC) programs that activate when the ambient temperature is expected to cross certain extreme thresholds are widely used to manage relevant public health risks. In practice, however, the effectiveness of these thresholds has rarely been examined. The goal of this study is to test if the activation criteria based on extreme temperature thresholds, both cold and heat, capture elevated health risks for all-cause and cause-specific mortality and morbidity in the Minneapolis-St. Paul Metropolitan Area. A distributed lag nonlinear model (DLNM) combined with a quasi-Poisson generalized linear model is used to derive the exposure-response functions between daily maximum heat index and mortality (1998-2014) and morbidity (emergency department visits; 2007-2014). Specific causes considered include cardiovascular, respiratory, renal diseases, and diabetes. Six extreme temperature thresholds, corresponding to 1st-3rd and 97th-99th percentiles of local exposure history, are examined. All six extreme temperature thresholds capture significantly increased relative risks for all-cause mortality and morbidity. However, the cause-specific analyses reveal heterogeneity. Extreme cold thresholds capture increased mortality and morbidity risks for cardiovascular and respiratory diseases and extreme heat thresholds for renal disease. Percentile-based extreme temperature thresholds are appropriate for initiating ERC targeting the general population. Tailoring ERC by specific causes may protect some but not all individuals with health conditions exacerbated by hazardous ambient temperature exposure. © 2018 Society for Risk Analysis.

Central-peripheral neural network interactions evoked by vagus nerve stimulation: functional consequences on control of cardiac function.

PubMed

Ardell, Jeffrey L; Rajendran, Pradeep S; Nier, Heath A; KenKnight, Bruce H; Armour, J Andrew

2015-11-15

Using vagus nerve stimulation (VNS), we sought to determine the contribution of vagal afferents to efferent control of cardiac function. In anesthetized dogs, the right and left cervical vagosympathetic trunks were stimulated in the intact state, following ipsilateral or contralateral vagus nerve transection (VNTx), and then following bilateral VNTx. Stimulations were performed at currents from 0.25 to 4.0 mA, frequencies from 2 to 30 Hz, and a 500-μs pulse width. Right or left VNS evoked significantly greater current- and frequency-dependent suppression of chronotropic, inotropic, and lusitropic function subsequent to sequential VNTx. Bradycardia threshold was defined as the current first required for a 5% decrease in heart rate. The threshold for the right vs. left vagus-induced bradycardia in the intact state (2.91 ± 0.18 and 3.47 ± 0.20 mA, respectively) decreased significantly with right VNTx (1.69 ± 0.17 mA for right and 3.04 ± 0.27 mA for left) and decreased further following bilateral VNTx (1.29 ± 0.16 mA for right and 1.74 ± 0.19 mA for left). Similar effects were observed following left VNTx. The thresholds for afferent-mediated effects on cardiac parameters were 0.62 ± 0.04 and 0.65 ± 0.06 mA with right and left VNS, respectively, and were reflected primarily as augmentation. Afferent-mediated tachycardias were maintained following β-blockade but were eliminated by VNTx. The increased effectiveness and decrease in bradycardia threshold with sequential VNTx suggest that 1) vagal afferents inhibit centrally mediated parasympathetic efferent outflow and 2) the ipsilateral and contralateral vagi exert a substantial buffering capacity. The intact threshold reflects the interaction between multiple levels of the cardiac neural hierarchy. Copyright © 2015 the American Physiological Society.

Central-peripheral neural network interactions evoked by vagus nerve stimulation: functional consequences on control of cardiac function

PubMed Central

Rajendran, Pradeep S.; Nier, Heath A.; KenKnight, Bruce H.; Armour, J. Andrew

2015-01-01

Using vagus nerve stimulation (VNS), we sought to determine the contribution of vagal afferents to efferent control of cardiac function. In anesthetized dogs, the right and left cervical vagosympathetic trunks were stimulated in the intact state, following ipsilateral or contralateral vagus nerve transection (VNTx), and then following bilateral VNTx. Stimulations were performed at currents from 0.25 to 4.0 mA, frequencies from 2 to 30 Hz, and a 500-μs pulse width. Right or left VNS evoked significantly greater current- and frequency-dependent suppression of chronotropic, inotropic, and lusitropic function subsequent to sequential VNTx. Bradycardia threshold was defined as the current first required for a 5% decrease in heart rate. The threshold for the right vs. left vagus-induced bradycardia in the intact state (2.91 ± 0.18 and 3.47 ± 0.20 mA, respectively) decreased significantly with right VNTx (1.69 ± 0.17 mA for right and 3.04 ± 0.27 mA for left) and decreased further following bilateral VNTx (1.29 ± 0.16 mA for right and 1.74 ± 0.19 mA for left). Similar effects were observed following left VNTx. The thresholds for afferent-mediated effects on cardiac parameters were 0.62 ± 0.04 and 0.65 ± 0.06 mA with right and left VNS, respectively, and were reflected primarily as augmentation. Afferent-mediated tachycardias were maintained following β-blockade but were eliminated by VNTx. The increased effectiveness and decrease in bradycardia threshold with sequential VNTx suggest that 1) vagal afferents inhibit centrally mediated parasympathetic efferent outflow and 2) the ipsilateral and contralateral vagi exert a substantial buffering capacity. The intact threshold reflects the interaction between multiple levels of the cardiac neural hierarchy. PMID:26371171

LinkImputeR: user-guided genotype calling and imputation for non-model organisms.

PubMed

Money, Daniel; Migicovsky, Zoë; Gardner, Kyle; Myles, Sean

2017-07-10

Genomic studies such as genome-wide association and genomic selection require genome-wide genotype data. All existing technologies used to create these data result in missing genotypes, which are often then inferred using genotype imputation software. However, existing imputation methods most often make use only of genotypes that are successfully inferred after having passed a certain read depth threshold. Because of this, any read information for genotypes that did not pass the threshold, and were thus set to missing, is ignored. Most genomic studies also choose read depth thresholds and quality filters without investigating their effects on the size and quality of the resulting genotype data. Moreover, almost all genotype imputation methods require ordered markers and are therefore of limited utility in non-model organisms. Here we introduce LinkImputeR, a software program that exploits the read count information that is normally ignored, and makes use of all available DNA sequence information for the purposes of genotype calling and imputation. It is specifically designed for non-model organisms since it requires neither ordered markers nor a reference panel of genotypes. Using next-generation DNA sequence (NGS) data from apple, cannabis and grape, we quantify the effect of varying read count and missingness thresholds on the quantity and quality of genotypes generated from LinkImputeR. We demonstrate that LinkImputeR can increase the number of genotype calls by more than an order of magnitude, can improve genotyping accuracy by several percent and can thus improve the power of downstream analyses. Moreover, we show that the effects of quality and read depth filters can differ substantially between data sets and should therefore be investigated on a per-study basis. By exploiting DNA sequence data that is normally ignored during genotype calling and imputation, LinkImputeR can significantly improve both the quantity and quality of genotype data generated from NGS technologies. It enables the user to quickly and easily examine the effects of varying thresholds and filters on the number and quality of the resulting genotype calls. In this manner, users can decide on thresholds that are most suitable for their purposes. We show that LinkImputeR can significantly augment the value and utility of NGS data sets, especially in non-model organisms with poor genomic resources.

Stationary statistical theory of two-surface multipactor regarding all impacts for efficient threshold analysis

NASA Astrophysics Data System (ADS)

Lin, Shu; Wang, Rui; Xia, Ning; Li, Yongdong; Liu, Chunliang

2018-01-01

Statistical multipactor theories are critical prediction approaches for multipactor breakdown determination. However, these approaches still require a negotiation between the calculation efficiency and accuracy. This paper presents an improved stationary statistical theory for efficient threshold analysis of two-surface multipactor. A general integral equation over the distribution function of the electron emission phase with both the single-sided and double-sided impacts considered is formulated. The modeling results indicate that the improved stationary statistical theory can not only obtain equally good accuracy of multipactor threshold calculation as the nonstationary statistical theory, but also achieve high calculation efficiency concurrently. By using this improved stationary statistical theory, the total time consumption in calculating full multipactor susceptibility zones of parallel plates can be decreased by as much as a factor of four relative to the nonstationary statistical theory. It also shows that the effect of single-sided impacts is indispensable for accurate multipactor prediction of coaxial lines and also more significant for the high order multipactor. Finally, the influence of secondary emission yield (SEY) properties on the multipactor threshold is further investigated. It is observed that the first cross energy and the energy range between the first cross and the SEY maximum both play a significant role in determining the multipactor threshold, which agrees with the numerical simulation results in the literature.

Central mechanisms of stress-induced headache.

PubMed

Cathcart, S; Petkov, J; Winefield, A H; Lushington, K; Rolan, P

2010-03-01

Stress is the most commonly reported trigger of an episode of chronic tension-type headache (CTTH); however, the causal significance has not been experimentally demonstrated to date. Stress may trigger CTTH through hyperalgesic effects on already sensitized pain pathways in CTTH sufferers. This hypothesis could be partially tested by examining pain sensitivity in an experimental model of stress-induced headache in CTTH sufferers. Such examinations have not been reported to date. We measured pericranial muscle tenderness and pain thresholds at the finger, head and shoulder in 23 CTTH sufferers (CTH-S) and 25 healthy control subjects (CNT) exposed to an hour-long stressful mental task, and in 23 CTTH sufferers exposed to an hour-long neutral condition (CTH-N). Headache developed in 91% of CTH-S, 4% of CNT, and 17% of CTH-N subjects. Headache sufferers had increased muscle tenderness and reduced pain thresholds compared with healthy controls. During the task, muscle tenderness increased and pain thresholds decreased in the CTH-S group compared with CTH-N and CNT groups. Pre-task muscle tenderness and reduction in pain threshold during task were predictive of the development and intensity of headache following task. The main findings are that stress induced a headache in CTTH sufferers, and this was associated with pre-task muscle tenderness and stress-induced reduction in pain thresholds. The results support the hypothesis that stress triggers CTTH through hyperalgesic effects on already increased pain sensitivity in CTTH sufferers, reducing the threshold to noxious input from pericranial structures.

Menstrual cycle and the temporal discrimination threshold.

PubMed

Mc Govern, Eavan M; O'Connor, Emer; Beiser, Ines; Williams, Laura; Butler, John S; Quinlivan, Brendan; Narasimham, Shruti; Beck, Rebecca; Reilly, Richard B; O'Riordan, Sean; Hutchinson, Michael

2017-02-01

The temporal discrimination threshold (TDT) is a proposed pre-clinical biomarker (endophenotype) for adult onset isolated focal dystonia (AOIFD). Age- and sex-related effects on temporal discrimination demonstrate that women, before the age of 40 years, have faster temporal discrimination than men but their TDTs worsen with age at almost three times the rate of men. Thus after 40 years the TDT in women is progressively worse than in men. AOIFD is an increasingly female-predominant disorder after the age of 40; it is not clear whether this age-related sexually-dimorphic difference observed for both the TDT and sex ratio at disease onset in AOIFD is a hormonal or chromosomal effect. The aim of this study was to examine temporal discrimination at weekly intervals during two consecutive menstrual cycles in 14 healthy female volunteers to determine whether physiological hormonal changes affected temporal discrimination. We observed no significant differences in weekly temporal discrimination threshold values during the menstrual cycles and no significant correlation with the menstrual cycle stage. This observed stability of temporal discrimination during cyclical hormonal change raises interesting questions concerning the age-related sexually-dimorphic decline observed in temporal discrimination. Our findings pave the way for future studies exploring potential pathomechanisms for this age-related deterioration.

Does a 3-month multidisciplinary intervention improve pain, body composition and physical fitness in women with fibromyalgia?

PubMed

Carbonell-Baeza, Ana; Aparicio, Virginia A; Ortega, Francisco B; Cuevas, Ana M; Alvarez, Inmaculada C; Ruiz, Jonatan R; Delgado-Fernandez, Manuel

2011-12-01

To determine the effects of a 3-month multidisciplinary intervention on pain (primary outcome), body composition and physical fitness (secondary outcomes) in women with fibromyalgia (FM). 75 women with FM were allocated to a low-moderate intensity 3-month (three times/week) multidisciplinary (pool, land-based and psychological sessions) programme (n=33) or to a usual care group (n=32). The outcome variables were pain threshold, body composition (body mass index and estimated body fat percentage) and physical fitness (30 s chair stand, handgrip strength, chair sit and reach, back scratch, blind flamingo, 8 feet up and go and 6 min walk test). The authors observed a significant interaction effect (group*time) for the left (L) and right (R) side of the anterior cervical (p<0.001) and the lateral epicondyle R (p=0.001) tender point. Post hoc analysis revealed that pain threshold increased in the intervention group (positive) in the anterior cervical R (p<0.001) and L (p=0.012), and in the lateral epicondyle R (p=0.010), whereas it decreased (negative) in the anterior cervical R (p<0.001) and L (p=0.002) in the usual care group. There was also a significant interaction effect for chair sit and reach. Post hoc analysis revealed improvement in the intervention group (p=0.002). No significant improvement attributed to the training was observed in the rest of physical fitness or body composition variables. A 3-month multidisciplinary intervention three times/week had a positive effect on pain threshold in several tender points in women with FM. Though no overall improvements were observed in physical fitness or body composition, the intervention had positive effects on lower-body flexibility.

Post-electroconvulsive therapy recovery and reorientation time with methohexital and ketamine: a randomized, longitudinal cross-over design trial

PubMed Central

Yen, Tony; Khafaja, Mohamad; Lam, Nicholas; Crumbacher, James; Schrader, Ronald; Rask, John; Billstrand, Mary; Rothfork, Jacob; Abbott, Christopher C.

2014-01-01

Objectives Methohexital, a barbiturate anesthetic commonly used for electroconvulsive therapy (ECT), possesses dose-dependent anticonvulsant properties, and its use can interfere with effective seizure therapy in patients with high seizure thresholds. Ketamine, a NMDA-antagonist with epileptogenic properties not broadly used for ECT inductions, is a commonly used induction agent for general anesthesia. Recent studies suggest that the use of ketamine is effective in allowing successful ECT treatment in patients with high seizure thresholds without an increase in side-effects. In this preliminary study, we directly compared the recovery and re-orientation times of subjects receiving ketamine and methohexital for ECTs. Methods Twenty patients were randomized in a cross-over design to receive methohexital and ketamine for ECT inductions in alternating fashion for six trials. Primary outcome measures were recovery time (voluntary movement, respiratory effort, blood pressure, consciousness, and O2 saturation) and re-orientation time. Secondary outcome measures were individual recovery variables, side-effect occurrence, and seizure duration. Results: Overall recovery time was not significantly different between the two treatment arms (F(1,17) = 0.72, P = 0.41). Re-orientation time was faster in the methohexital arm (F(1,17) = 9.23, P = 0.007). Conclusion Ketamine inductions resulted in higher number of side-effects, higher subject dropout rates, and a longer reorientation time with respect to methohexital inductions. No significant difference in post-anesthesia recovery time was found between the ketamine and methohexital arms. Intolerability to ketamine affected a significant proportion of subjects, and suggests that ketamine should remain as an alternative or adjunctive agent for patients with high seizure thresholds. PMID:24755722

Tactile learning and the individual evaluation of the reward in honey bees (Apis mellifera L.).

PubMed

Scheiner, R; Erber, J; Page, R E

1999-07-01

Using the proboscis extension response we conditioned pollen and nectar foragers of the honey bee (Apis mellifera L.) to tactile patterns under laboratory conditions. Pollen foragers demonstrated better acquisition, extinction, and reversal learning than nectar foragers. We tested whether the known differences in response thresholds to sucrose between pollen and nectar foragers could explain the observed differences in learning and found that nectar foragers with low response thresholds performed better during acquisition and extinction than ones with higher thresholds. Conditioning pollen and nectar foragers with similar response thresholds did not yield differences in their learning performance. These results suggest that differences in the learning performance of pollen and nectar foragers are a consequence of differences in their perception of sucrose. Furthermore, we analysed the effect which the perception of sucrose reward has on associative learning. Nectar foragers with uniform low response thresholds were conditioned using varying concentrations of sucrose. We found significant positive correlations between the concentrations of the sucrose rewards and the performance during acquisition and extinction. The results are summarised in a model which describes the relationships between learning performance, response threshold to sucrose, concentration of sucrose and the number of rewards.

Effect of Workplace Noise on Hearing Ability in Tile and Ceramic Industry Workers in Iran: A 2-Year Follow-Up Study

PubMed Central

Mirmohammadi, Seyyed Jalil; Mehrparvar, Amir Houshang; Mollasadeghi, Abolfazl

2013-01-01

Introduction. Noise as a common physical hazard may lead to noise-induced hearing loss, an irreversible but preventable disorder. Annual audiometric evaluations help detect changes in hearing status before clinically significant hearing loss develops. This study was designed to track hearing threshold changes during 2-year follow-up among tile and ceramic workers. Methods. This follow-up study was conducted on 555 workers (totally 1110 ears). Subjects were divided into four groups according to the level of noise exposure. Hearing threshold in conventional audiometric frequencies was measured and standard threshold shift was calculated for each ear. Results. Hearing threshold was increased during 2 years of follow-up. Increased hearing threshold was most frequently observed at 4000, 6000, and 3000 Hz. Standard threshold shift was observed in 13 (2.34%), 49 (8.83%), 22 (3.96%), and 63 (11.35%) subjects in the first and second years of follow-up in the right and left ears, respectively. Conclusions. This study has documented a high incidence of noise-induced hearing loss in tile and ceramic workers that would put stress on the importance of using hearing protection devices. PMID:24453922

Streamflow losses in the Black Hills of western South Dakota

USGS Publications Warehouse

Hortness, Jon E.; Driscoll, Daniel G.

1998-01-01

Losses occur in numerous streams that cross outcrops of various sedimentary rocks that are exposed around the periphery of the Black Hills of South Dakota. These streamflow losses are recognized as an important source of local recharge to regional bedrock aquifers. Most streams lose all of their flow up to some threshold rate. Streamflow is maintained through a loss zone when the threshold is exceeded. Streamflow records for 86 measurement sites are used to determine bedrock loss thresholds for 24 area streams, which have individual loss thresholds that range from negligible (no loss) to as much as 50 cubic feet per second. In addition, insights are provided regarding springflow that occurs in the immediate vicinity of selected loss zones. Most losses occur to outcrops of the Madison Limestone and Minnelusa Formation. Losses to the Deadwood Formation probably are minimal. Losses to the Minnekahta Limestone generally are small; however, they are difficult to quantify because of potential losses to extensive alluvial deposits that commonly are located near Minnekahta outcrops. Loss thresholds for each stream are shown to be relatively constant, without measurable effects from streamflow rates or duration of flow through the loss zones. Calculated losses for measurements made during high-flow conditions generally have larger variability than calculated losses for low-flow conditions; however, consistent relations between losses and streamflow have not been identified. Some of this variability results from the inability to account for tributary inflows and changes in storage. Calculated losses are shown to decrease, in some cases, during periods of extended flow through loss zones. Decreased 'net' losses, however, generally can be attributed to springflow (ground-water discharge) within a loss zone, which may occur during prolonged periods of wet climatic conditions. Losses to unsaturated alluvial deposits located adjacent to the stream channels are found to have significant effects on determination of bedrock losses. Large losses occur in filling initial storage in unsaturated alluvial deposits downstream from loss zones, when bedrock loss thresholds are first exceeded. Losses to alluvial deposits in the range of tens of cubic feet per second and alluvial storage capacities in the range of hundreds of acre-feet are documented. Significant changes in loss thresholds for Grace Coolidge Creek, Spring Creek, and Whitewood Creek are documented. Introduction of large quantities of fine-grained sediments into these stream channels may have affected loss thresholds for various periods of time.

Auditory Function in Rhesus Monkeys: Effects of Aging and Caloric Restriction in the Wisconsin Monkeys Five Years Later

PubMed Central

Fowler, Cynthia G.; Chiasson, Kirstin Beach; Leslie, Tami Hanson; Thomas, Denise; Beasley, T. Mark; Kemnitz, Joseph W.; Weindruch, Richard

2010-01-01

Caloric restriction (CR) slows aging in many species and protects some animals from age-related hearing loss (ARHL), but the effect on humans is not yet known. Because rhesus monkeys are long-lived primates that are phylogenically closer to humans than other research animals are, they provide a better model for studying the effects of CR in aging and ARHL. Subjects were from the pool of 55 rhesus monkeys aged 15–28 years who had been in the Wisconsin study on CR and aging for 8–13.5 years. Distortion product otoacoustic emissions (DPOAE) with f2 frequencies from 2211–8837 Hz and auditory brainstem response (ABR) thresholds from clicks and 8, 16, and 32 kHz tone bursts were obtained. DPOAE levels declined linearly at approximately 1 dB/year, but that rate doubled for the highest frequencies in the oldest monkeys. There were no interactions for diet condition or sex. ABR thresholds to clicks and tone bursts showed increases with aging. Borderline significance was shown for diet in the thresholds at 8 kHz stimuli, with monkeys on caloric restriction having lower thresholds. Because the rhesus monkeys have a maximum longevity of 40 years, the full benefits of CR may not yet be realized. PMID:20079820

Effect of Hearing Aids on Auditory Function in Infants with Perinatal Brain Injury and Severe Hearing Loss

PubMed Central

Moreno-Aguirre, Alma Janeth; Santiago-Rodríguez, Efraín; Harmony, Thalía; Fernández-Bouzas, Antonio

2012-01-01

Background Approximately 2–4% of newborns with perinatal risk factors present with hearing loss. Our aim was to analyze the effect of hearing aid use on auditory function evaluated based on otoacoustic emissions (OAEs), auditory brain responses (ABRs) and auditory steady state responses (ASSRs) in infants with perinatal brain injury and profound hearing loss. Methodology/Principal Findings A prospective, longitudinal study of auditory function in infants with profound hearing loss. Right side hearing before and after hearing aid use was compared with left side hearing (not stimulated and used as control). All infants were subjected to OAE, ABR and ASSR evaluations before and after hearing aid use. The average ABR threshold decreased from 90.0 to 80.0 dB (p = 0.003) after six months of hearing aid use. In the left ear, which was used as a control, the ABR threshold decreased from 94.6 to 87.6 dB, which was not significant (p>0.05). In addition, the ASSR threshold in the 4000-Hz frequency decreased from 89 dB to 72 dB (p = 0.013) after six months of right ear hearing aid use; the other frequencies in the right ear and all frequencies in the left ear did not show significant differences in any of the measured parameters (p>0.05). OAEs were absent in the baseline test and showed no changes after hearing aid use in the right ear (p>0.05). Conclusions/Significance This study provides evidence that early hearing aid use decreases the hearing threshold in ABR and ASSR assessments with no functional modifications in the auditory receptor, as evaluated by OAEs. PMID:22808289

Effect of detomidine on visceral and somatic nociception and duodenal motility in conscious adult horses.

PubMed

Elfenbein, Johanna R; Sanchez, L Chris; Robertson, Sheilah A; Cole, Cynthia A; Sams, Richard

2009-03-01

To evaluate the effects of detomidine on visceral and somatic nociception, heart and respiratory rates, sedation, and duodenal motility and to correlate these effects with serum detomidine concentrations. Nonrandomized, experimental trial. Five adult horses, each with a permanent gastric cannula weighing 534 +/- 46 kg. Visceral nociception was evaluated by colorectal (CRD) and duodenal distension (DD). The duodenal balloon was used to assess motility. Somatic nociception was assessed via thermal threshold (TT). Nose-to-ground (NTG) height was used as a measure of sedation. Serum was collected for pharmacokinetic analysis. Detomidine (10 or 20 microg kg(-1)) was administered intravenously. Data were analyzed by means of a three-factor anova with fixed factors of treatment and time and random factor of horse. When a significant time x treatment interaction was detected, differences were compared with a simple t-test or Bonferroni t-test. Significance was set at p < 0.05. Detomidine produced a significant, dose-dependent decrease in NTG height, heart rate, and skin temperature and a significant, nondose-dependent decrease in respiratory rate. Colorectal distension threshold was significantly increased with 10 microg kg(-1) for 15 minutes and for at least 165 minutes with 20 microg kg(-1). Duodenal distension threshold was significantly increased at 15 minutes for the 20 microg kg(-1) dose. A significant change in TT was not observed at either dose. A marked, immediate decrease in amplitude of duodenal contractions followed detomidine administration at both doses for 50 minutes. Detomidine caused a longer period of visceral anti-nociception as determined by CRD but a shorter period of anti-nociception as determined by DD than has been previously reported. The lack of somatic anti-nociception as determined by TT testing may be related to the marked decrease in skin temperature, likely caused by peripheral vasoconstriction and the low temperature cut-off of the testing device.

A prospective study on radiation-induced changes in hearing function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herrmann, Franziska; Doerr, Wolfgang; Experimental Center, Medical Faculty Carl Gustav Carus, University of Technology-Dresden, Dresden

Purpose: To quantitate changes in hearing function after radiotherapy for head-and-neck tumors. Methods and Materials: At the Department of Radiotherapy and Radiation Oncology, 32 patients were irradiated for head-and-neck tumors. Three-dimensional treatment planning was applied. Total tumor doses were 30.0-77.6 Gy, local doses to the inner ear (n = 64) ranged from 1.7 to 64.3 Gy. Audiometry was performed before the onset of radiotherapy (RT), at a tumor dose of 40 Gy or at the end of palliative treatment, at the end of curative RT, and 2-6 months post-RT. Assays applied were frequency-specific threshold measurements for air and bone conduction,more » measurements according to Weber and Rinne, tympanometry and assessment of the stapedius reflex. Results: Age and prior disease significantly decreased, whereas previous or concurrent alcohol consumption significantly increased hearing ability. A significant reduction in hearing ability during RT was found for high frequencies (at 40 Gy) and low frequencies (at end of RT), which persisted after RT. No differences were observed for air or bone conduction. None of the other assays displayed time- or dose-dependent changes. Dose-effect analyses revealed an ED50 (dose at which a 50% incidence is expected) for significant changes in hearing thresholds (15 dB) in the range of 20-25 Gy, with large confidence limits. Conclusions: Radiation effects on hearing ability were confined to threshold audiogram values, which started during the treatment without reversibility during 6 months postradiotherapy.« less

Effectiveness of an oral health educational program on community-dwelling older people with xerostomia.

PubMed

Ohara, Yuki; Yoshida, Naomi; Kono, Yoko; Hirano, Hirohiko; Yoshida, Hideyo; Mataki, Shiro; Sugimoto, Kumiko

2015-04-01

The purpose of the present study was to evaluate the changes in oral health and function through an oral health educational program for the independent older people with xerostomia. Community-dwelling older people with xerostomia aged over 65 years who participated in a preliminary comprehensive health survey in 2011 were recruited for the educational program. A total of 47 participants were randomly assigned into two groups, the intervention group (n = 26) and the control group (n = 21). The intervention group attended a 90-min oral health education program every 2 weeks for 3 months. The program consisted of oral hygiene instruction, facial and tongue muscle exercise, and salivary gland massage. The control group was provided only general information about oral health. The assessments of oral function, such as oral diadochokinesis of articulation, swallowing, taste threshold and salivary flow rate, were carried out before and after 3 months with or without intervention. A total of 38 participants (21 of intervention group and 17 of control group) completed the study protocol. In the intervention group, resting salivation significantly improved after the program. The second and third cumulated Repetitive Saliva Swallowing Test times significantly improved in the intervention group. The threshold for bitterness significantly lowered in the intervention group, whereas the sour threshold significantly heightened in the control group after 3 months (P < 0.05). The present study suggests that the educational program targeting oral function improvement is effective among the independent older population. © 2014 Japan Geriatrics Society.

Effect of ferroelectric BaTiO3 particles on the threshold voltage of a smectic A liquid crystal.

PubMed

Imamaliyev, Abbas Rahim; Ramazanov, Mahammadali Ahmad; Humbatov, Shirkhan Arastun

2018-01-01

The influence of small ferroelectric BaTiO 3 particles on the planar-homeotropic transition threshold voltage in smectic A liquid crystals consisting of p -nitrophenyl p -decyloxybenzoate and 4-cyano-4'-pentylbiphenyl were studied by using capacitance-voltage ( C - V ) measurements. It was shown that the BaTiO 3 particles significantly reduce the threshold voltage. The obtained result is explained by two factors: an increase of dielectric anisotropy of the liquid crystals and the formation of a strong electric field near polarized particles of BaTiO 3 . It was shown that the role of the second factor is dominant. The explanations of some features observed in the C - V characteristics are given.

Solitary pulse-on-demand production by optical injection locking of passively Q-switched InGaN diode laser near lasing threshold

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, X., E-mail: xi.zeng@csem.ch, E-mail: dmitri.boiko@csem.ch; Stadelmann, T.; Grossmann, S.

2015-02-16

In this letter, we investigate the behavior of a Q-switched InGaN multi-section laser diode (MSLD) under optical injection from a continuous wave external cavity diode laser. We obtain solitary optical pulse generation when the slave MSLD is driven near free running threshold, and the peak output power is significantly enhanced with respect to free running configuration. When the slave laser is driven well above threshold, optical injection reduces the peak power. Using standard semiconductor laser rate equation model, we find that both power enhancement and suppression effects are the result of partial bleaching of the saturable absorber by externally injectedmore » photons.« less

Extrafoveally applied flashing light affects contrast thresholds of achromatic and S-cone isolating, but not L-M cone modulated stimuli.

PubMed

Őze, A; Puszta, A; Buzás, P; Kóbor, P; Braunitzer, G; Nagy, A

2018-06-21

Flashing light stimulation is often used to investigate the visual system. However, the magnitude of the effect of this stimulus on the various subcortical pathways is not well investigated. The signals of conscious vision are conveyed by the magnocellular, parvocellular and koniocellular pathways. Parvocellular and koniocellular pathways (or more precisely, the L-M opponent and S-cone isolating channels) can be accessed by isoluminant red-green (L-M) and S-cone isolating stimuli, respectively. The main goal of the present study was to explore how costimulation with strong white extrafoveal light flashes alters the perception of stimuli specific to these pathways. Eleven healthy volunteers with negative neurological and ophthalmological history were enrolled for the study. Isoluminance of L-M and S-cone isolating sine-wave gratings was set individually, using the minimum motion procedure. The contrast thresholds for these stimuli as well as for achromatic gratings were determined by an adaptive staircase procedure where subjects had to indicate the orientation (horizontal, oblique or vertical) of the gratings. Thresholds were then determined again while a strong white peripheral light flash was presented 50 ms before each trial. Peripheral light flashes significantly (p < 0.05) increased the contrast thresholds of the achromatic and S-cone isolating stimuli. The threshold elevation was especially marked in case of the achromatic stimuli. However, the contrast threshold for the L-M stimuli was not significantly influenced by the light flashes. We conclude that extrafoveally applied light flashes influence predominantly the perception of achromatic stimuli. Copyright © 2018 Elsevier B.V. All rights reserved.

Delayed changes in auditory status in cochlear implant users with preserved acoustic hearing.

PubMed

Scheperle, Rachel A; Tejani, Viral D; Omtvedt, Julia K; Brown, Carolyn J; Abbas, Paul J; Hansen, Marlan R; Gantz, Bruce J; Oleson, Jacob J; Ozanne, Marie V

2017-07-01

This retrospective review explores delayed-onset hearing loss in 85 individuals receiving cochlear implants designed to preserve acoustic hearing at the University of Iowa Hospitals and Clinics between 2001 and 2015. Repeated measures of unaided behavioral audiometric thresholds, electrode impedance, and electrically evoked compound action potential (ECAP) amplitude growth functions were used to characterize longitudinal changes in auditory status. Participants were grouped into two primary categories according to changes in unaided behavioral thresholds: (1) stable hearing or symmetrical hearing loss and (2) delayed loss of hearing in the implanted ear. Thirty-eight percent of this sample presented with delayed-onset hearing loss of various degrees and rates of change. Neither array type nor insertion approach (round window or cochleostomy) had a significant effect on prevalence. Electrode impedance increased abruptly for many individuals exhibiting precipitous hearing loss; the increase was often transient. The impedance increases were significantly larger than the impedance changes observed for individuals with stable or symmetrical hearing loss. Moreover, the impedance changes were associated with changes in behavioral thresholds for individuals with a precipitous drop in behavioral thresholds. These findings suggest a change in the electrode environment coincident with the change in auditory status. Changes in ECAP thresholds, growth function slopes, and suprathreshold amplitudes were not correlated with changes in behavioral thresholds, suggesting that neural responsiveness in the region excited by the implant is relatively stable. Further exploration into etiology of delayed-onset hearing loss post implantation is needed, with particular interest in mechanisms associated with changes in the intracochlear environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of Ventilatory Measures and 20 km Time Trial Performance.

PubMed

Peveler, Willard W; Shew, Brandy; Johnson, Samantha; Sanders, Gabe; Kollock, Roger

2017-01-01

Performance threshold measures are used to predict cycling performance. Previous research has focused on long time trials (≥ 40 km) using power at ventilatory threshold and respiratory threshold to estimate time trial performance. As intensity greatly differs during shorter time trails applying findings from longer time trials may not be appropriate. The use of heart rate measures to determine 20 km time trial performance has yet to be examined. The purpose of this study was to determine the effectiveness of heart rate measures at ventilatory threshold (VE/VO 2 Plotted and VT determined by software) and respiratory threshold (RER of 0.95, 1.00, and 1.05) to predict 20 km time trial performance. Eighteen cyclists completed a VO 2max protocol and two 20 km time trials. Average heart rates from 20 km time trials were compared with heart rates from performance threshold measures (VT plotted, VT software, and an RER at 0.95, 1.00, and 1.05) using repeated measures ANOVA. Significance was set a priori at P ≤ 0.05. The only measure not found to be significantly different in relation to time trial performance was HR at an RER of 1.00 (166.61±12.70 bpm vs. 165.89 ± 9.56 bpm, p = .671). VT plotting and VT determined by software were found to underestimate time trial performance by 3% and 8% respectively. From these findings it is recommended to use heart rate at a RER of 1.00 in order to determine 20 km time trial intensity.

Thresholds for the cost-effectiveness of interventions: alternative approaches.

PubMed

Marseille, Elliot; Larson, Bruce; Kazi, Dhruv S; Kahn, James G; Rosen, Sydney

2015-02-01

Many countries use the cost-effectiveness thresholds recommended by the World Health Organization's Choosing Interventions that are Cost-Effective project (WHO-CHOICE) when evaluating health interventions. This project sets the threshold for cost-effectiveness as the cost of the intervention per disability-adjusted life-year (DALY) averted less than three times the country's annual gross domestic product (GDP) per capita. Highly cost-effective interventions are defined as meeting a threshold per DALY averted of once the annual GDP per capita. We argue that reliance on these thresholds reduces the value of cost-effectiveness analyses and makes such analyses too blunt to be useful for most decision-making in the field of public health. Use of these thresholds has little theoretical justification, skirts the difficult but necessary ranking of the relative values of locally-applicable interventions and omits any consideration of what is truly affordable. The WHO-CHOICE thresholds set such a low bar for cost-effectiveness that very few interventions with evidence of efficacy can be ruled out. The thresholds have little value in assessing the trade-offs that decision-makers must confront. We present alternative approaches for applying cost-effectiveness criteria to choices in the allocation of health-care resources.

Amplification of transcutaneous and percutaneous bone-conduction devices with a test-band in an induced model of conductive hearing loss.

PubMed

Park, Marn Joon; Lee, Jae Ryung; Yang, Chan Joo; Yoo, Myung Hoon; Jin, In Suk; Choi, Chi Ho; Park, Hong Ju

2016-11-01

Transcutaneous devices have a disadvantage, the dampening effect by soft tissue between the bone and devices. We investigated hearing outcomes with percutaneous and transcutaneous devices using test-bands in an induced unilateral conductive hearing loss. Comparison of hearing outcomes of two devices in the same individuals. The right ear was plugged in 30 subjects and a test-band with devices (Cochlear™ Baha® BP110 Power and Sophono® Alpha-2 MPO™) was applied on the right mastoid tip with the left ear masked. Sound-field thresholds, speech recognition thresholds (SRTs), and word recognition scores (WRSs) were compared. Aided thresholds of Sophono were significantly better than those of Baha at most frequencies. Sophono WRSs (86 ± 12%) at 40 dB SPL and SRTs (14 ± 5 dB HL) were significantly better than those (73 ± 24% and 23 ± 8 dB HL) of Baha. However, Sophono WRSs (98 ± 3%) at 60 dB SPL did not differ from Baha WRSs (95 ± 12%). Amplifications of the current transcutaneous device were not inferior to those of percutaneous devices with a test-band in subjects with normal bone-conduction thresholds. Since the percutaneous devices can increase the gain when fixed to the skull by eliminating the dampening effect, both devices are expected to provide sufficient hearing amplification.

Protective effects of vitamins E, B and C and L-carnitine in the prevention of cisplatin-induced ototoxicity in rats.

PubMed

Tokgöz, S Alicura; Vuralkan, E; Sonbay, N D; Çalişkan, M; Saka, C; Beşalti, Ö; Akin, İ

2012-05-01

This experimental study aimed to investigate the effects of vitamins E, B and C and L-carnitine in preventing cisplatin-induced ototoxicity. Twenty-five adult, male, Wistar albino rats were randomly allocated to receive intraperitoneal cisplatin either alone or preceded by vitamins B, E or C or L-carnitine. Auditory brainstem response (i.e. hearing thresholds and wave I-IV intervals) and distortion product otoacoustic emissions (i.e. signal-to-noise ratios) were recorded before and 72 hours after cisplatin administration. The following statistically significant differences were seen: control group pre- vs post-treatment wave I-IV interval values (p < 0.05); control vs vitamin E and B groups' I-IV interval values (p < 0.05); control vs other groups' hearing thresholds; vitamin E vs vitamin B and C and L-carnitine groups' hearing thresholds (p < 0.05); and vitamin B vs vitamin C and L-carnitine groups' hearing thresholds (p < 0.05). Statistically significant decreases were seen when comparing the initial and final signal-to-noise ratios in the control, vitamin B and L-carnitine groups (2000 and 3000 Hz; p < 0.01), and the initial and final signal-to-noise ratios in the control group (at 4000 Hz; p < 0.01). Vitamins B, E and C and L-carnitine appear to reduce cisplatin-induced ototoxicity in rats. The use of such additional treatments to decrease cisplatin-induced ototoxicity in humans is still under discussion.

Cost-Effectiveness Comparison of Imaging-Guided Prostate Biopsy Techniques: Systematic Transrectal Ultrasound, Direct In-Bore MRI, and Image Fusion.

PubMed

Venderink, Wulphert; Govers, Tim M; de Rooij, Maarten; Fütterer, Jurgen J; Sedelaar, J P Michiel

2017-05-01

Three commonly used prostate biopsy approaches are systematic transrectal ultrasound guided, direct in-bore MRI guided, and image fusion guided. The aim of this study was to calculate which strategy is most cost-effective. A decision tree and Markov model were developed to compare cost-effectiveness. Literature review and expert opinion were used as input. A strategy was deemed cost-effective if the costs of gaining one quality-adjusted life year (incremental cost-effectiveness ratio) did not exceed the willingness-to-pay threshold of €80,000 (≈$85,000 in January 2017). A base case analysis was performed to compare systematic transrectal ultrasound- and image fusion-guided biopsies. Because of a lack of appropriate literature regarding the accuracy of direct in-bore MRI-guided biopsy, a threshold analysis was performed. The incremental cost-effectiveness ratio for fusion-guided biopsy compared with systematic transrectal ultrasound-guided biopsy was €1386 ($1470) per quality-adjusted life year gained, which was below the willingness-to-pay threshold and thus assumed cost-effective. If MRI findings are normal in a patient with clinically significant prostate cancer, the sensitivity of direct in-bore MRI-guided biopsy has to be at least 88.8%. If that is the case, the incremental cost-effectiveness ratio is €80,000 per quality-adjusted life year gained and thus cost-effective. Fusion-guided biopsy seems to be cost-effective compared with systematic transrectal ultrasound-guided biopsy. Future research is needed to determine whether direct in-bore MRI-guided biopsy is the best pathway; in this study a threshold was calculated at which it would be cost-effective.

Comparing Trigger Point Dry Needling and Manual Pressure Technique for the Management of Myofascial Neck/Shoulder Pain: A Randomized Clinical Trial.

PubMed

De Meulemeester, Kayleigh E; Castelein, Birgit; Coppieters, Iris; Barbe, Tom; Cools, Ann; Cagnie, Barbara

2017-01-01

The aim of this study was to investigate short-term and long-term treatment effects of dry needling (DN) and manual pressure (MP) technique with the primary goal of determining if DN has better effects on disability, pain, and muscle characteristics in treating myofascial neck/shoulder pain in women. In this randomized clinical trial, 42 female office workers with myofascial neck/shoulder pain were randomly allocated to either a DN or MP group and received 4 treatments. They were evaluated with the Neck Disability Index, general numeric rating scale, pressure pain threshold, and muscle characteristics before and after treatment. For each outcome parameter, a linear mixed-model analysis was applied to reveal group-by-time interaction effects or main effects for the factor "time." No significant differences were found between DN and MP. In both groups, significant improvement in the Neck Disability Index was observed after 4 treatments and 3 months (P < .001); the general numerical rating scale also significantly decreased after 3 months. After the 4-week treatment program, there was a significant improvement in pain pressure threshold, muscle elasticity, and stiffness. Both treatment techniques lead to short-term and long-term treatment effects. Dry needling was found to be no more effective than MP in the treatment of myofascial neck/shoulder pain. Copyright © 2016. Published by Elsevier Inc.

Thermal sensitivity and cardiovascular reactivity to stress in healthy males.

PubMed

Conde-Guzón, Pablo Antonio; Bartolomé-Albistegui, María Teresa; Quirós, Pilar; Cabestrero, Raúl

2011-11-01

This paper examines the association of cardiovascular reactivity with thermal thresholds (detection and unpleasantness). Heart period (HP), systolic (SBP) and diastolic (DBP) blood pressure of 42 health young males were recorded during a cardiovascular reactivity task (a videogame based upon Sidman's avoidance paradigm). Thermal sensitivity, assessing detection and unpleasantness thresholds with radiant heat in the forearm was also estimated for participants. Participants with differential scores in the cardiovascular variables from base line to task > or = P65 were considered as reactors and those how have differential scores < or = P35 were considered as non-reactors. Significant differences were observed between groups in the unpleasantness thresholds in blood pressure (BP) but not in HP. Reactors exhibited significant higher unpleasantness thresholds than non-reactors. No significant differences were obtained in detection thresholds between groups.

Effect of morphine-induced antinociception is altered by AF64A-induced lesions on cholinergic neurons in rat nucleus raphe magnus.

PubMed

Abe, Kenji; Ishida, Kota; Kato, Masatoshi; Shigenaga, Toshiro; Taguchi, Kyoji; Miyatake, Tadashi

2002-11-01

To examine the role of cholinergic neurons in the nucleus raphe magnus (NRM) in noxious heat stimulation and in the effects of morphine-induced antinociception by rats. After the cholinergic neuron selective toxin, AF64A, was microinjected into the NRM, we examined changes in the antinociceptive threshold and effects of morphine (5 mg/kg, ip) using the hot-plate (HP) and tail-flick (TF) tests. Systemic administration of morphine inhibited HP and TF responses in control rats. Microinjection of AF64A (2 nmol/site) into the NRM significantly decreased the threshold of HP response after 14 d, whereas the TF response was not affected. Morphine-induced antinociception was significantly attenuated in rats administered AF64A. Extracellular acetylcholine was attenuated after 14 d to below detectable levels in rats given AF64A. Naloxone (1 microg/site) microinjected into control rat NRM also antagonized the antinociceptive effect of systemic morphine. These findings suggest that cholinergic neuron activation in the NRM modulates the antinociceptive effect of morphine simultaneously with the opiate system.

Do Contemporary Randomized Controlled Trials Meet ESMO Thresholds for Meaningful Clinical Benefit?

PubMed

Del Paggio, J C; Azariah, B; Sullivan, R; Hopman, W M; James, F V; Roshni, S; Tannock, I F; Booth, C M

2017-01-01

The European Society for Medical Oncology (ESMO) recently released a magnitude of clinical benefit scale (ESMO-MCBS) for systemic therapies for solid cancers. Here, we evaluate contemporary randomized controlled trials (RCTs) against the proposed ESMO thresholds for meaningful clinical benefit. RCTs evaluating systemic therapy for breast cancer, nonsmall cell lung cancer (NSCLC), colorectal cancer (CRC), and pancreatic cancer published 2011-2015 were reviewed. Data were abstracted regarding trial characteristics and outcomes, and these were applied to the ESMO-MCBS. We also determined whether RCTs were designed to detect an effect that would meet clinical benefit as defined by the ESMO-MCBS. About 277 eligible RCTs were included (40% breast, 31% NSCLC, 22% CRC, 6% pancreas). Median sample size was 532 and 83% were funded by industry. Among all 277 RCTs, the experimental therapy was statistically superior to the control arm in 138 (50%) trials: results of only 31% (43/138) of these trials met the ESMO-MCBS clinical benefit threshold. RCTs with curative intent were more likely to meet clinically meaningful thresholds than those with palliative intent [61% (19/31) versus 22% (24/107), P < 0.001]. Among the 226 RCTs for which the ESMO-MCBS could be applied, 31% (70/226) were designed to detect an effect size that could meet ESMO-MCBS thresholds. Less than one-third of contemporary RCTs with statistically significant results meet ESMO thresholds for meaningful clinical benefit, and this represents only 15% of all published trials. Investigators, funding agencies, regulatory agencies, and industry should adopt more stringent thresholds for meaningful benefit in the design of future RCTs. © The Author 2016. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Significance of the gate voltage-dependent mobility in the electrical characterization of organic field effect transistors

NASA Astrophysics Data System (ADS)

Kim, Jong Beom; Lee, Dong Ryeol

2018-04-01

We studied the effect of the addition of free hole- and electron-rich organic molecules to organic semiconductors (OSCs) in organic field effect transistors (OFETs) on the gate voltage-dependent mobility. The drain current versus gate voltage characteristics were quantitatively analyzed using an OFET mobility model of power law behavior based on hopping transport in an OSC. This analysis distinguished the threshold voltage shifts, depending on the materials and structures of the OFET device, and properly estimated the hopping transport of the charge carriers induced by the gate bias within the OSC from the power law exponent parameter. The addition of pentacene or C60 molecules to a one-monolayer pentacene-based OFET shifted the threshold voltages negatively or positively, respectively, due to the structural changes that occurred in the OFET device. On the other hand, the power law parameters revealed that the addition of charge carriers of the same or opposite polarity enhanced or hindered hopping transport, respectively. This study revealed the need for a quantitative analysis of the gate voltage-dependent mobility while distinguishing this effect from the threshold voltage effect in order to understand OSC hopping transport in OFETs.

THE EFFECTS OF VARIATIONS IN THE CONCENTRATION OF OXYGEN AND OF GLUCOSE ON DARK ADAPTATION

PubMed Central

McFarland, R. A.; Forbes, W. H.

1940-01-01

In this study we have analyzed the effects of variations in the concentrations of oxygen and of blood sugar on light sensitivity; i.e. dark adaptation. The experiments were carried out in an air-conditioned light-proof chamber where the concentrations of oxygen could be changed by dilution with nitrogen or by inhaling oxygen from a cylinder. The blood sugar was lowered by the injection of insulin and raised by the ingestion of glucose. The dark adaptation curves were plotted from data secured with an apparatus built according to specifications outlined by Hecht and Shlaer. During each experiment, observations were first made in normal air with the subject under basal conditions followed by one, and in most instances two, periods under the desired experimental conditions involving either anoxia or hyper- or hypoglycemia or variations in both the oxygen tension and blood sugar at the same time. 1. Dark adaptation curves were plotted (threshold against time) in normal air and compared with those obtained while inhaling lowered concentrations of oxygen. A decrease in sensitivity was observed with lowered oxygen tensions. Both the rod and cone portions of the curves were influenced in a similar way. These effects were counteracted by inhaling oxygen, the final rod thresholds returning to about the level of the normal base line in air or even below it within 2 to 3 minutes. The impairment was greatest for those with a poorer tolerance for low O2. Both the inter- and intra-individual variability in thresholds increased significantly at the highest altitude. 2. In a second series of tests control curves were obtained in normal air. Then while each subject remained dark adapted, the concentrations of oxygen were gradually decreased. The regeneration of visual purple was apparently complete during the 40 minutes of dark adaptation, yet in each case the thresholds continued to rise in direct proportion to the degree of anoxia. The inhalation of oxygen from a cylinder quickly counteracted the effects for the thresholds returned to the original control level within 2 to 3 minutes. 3. In experiments where the blood sugar was raised by the ingestion of glucose in normal air, no significant changes in the thresholds were observed except when the blood sugar was rapidly falling toward the end of the glucose tolerance tests. However, when glucose was ingested at the end of an experiment in low oxygen, while the subject remained dark adapted, the effects of the anoxia were largely counteracted within 6 to 8 minutes. 4. The influence of low blood sugar on light sensitivity was then studied by injecting insulin. The thresholds were raised as soon as the effects of the insulin produced a fall in the blood sugar. When the subjects inhaled oxygen the thresholds were lowered. Then when the oxygen was withdrawn so that the subject was breathing normal air, the thresholds rose again within 1 to 2 minutes. Finally, if the blood sugar was raised by ingesting glucose, the average threshold fell to the original control level or even below it. 5. The combined effects of low oxygen and low blood sugar on light sensitivity were studied in one subject (W. F.). These effects appeared to be greater than when a similar degree of anoxia or hypoglycemia was brought about separately. 6. In a series of experiments on ten subjects the dark adaptation curves were obtained both in the basal state and after a normal breakfast. In nine of the ten subjects, the food increased the sensitivity of the subjects to light. 7. The experiments reported above lend support to the hypothesis that both anoxia and hypoglycemia produce their effects on light sensitivity in essentially the same way; namely, by slowing the oxidative processes. Consequently the effects of anoxia may be ameliorated by giving glucose and the effects of hypoglycemia by inhaling oxygen. In our opinion, the changes may be attributed directly to the effects on the nervous tissue of the visual mechanism and the brain rather than on the photochemical processes of the retina. PMID:19873200

Predicting Nonauditory Adverse Radiation Effects Following Radiosurgery for Vestibular Schwannoma: A Volume and Dosimetric Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayhurst, Caroline; Monsalves, Eric; Bernstein, Mark

2012-04-01

Purpose: To define clinical and dosimetric predictors of nonauditory adverse radiation effects after radiosurgery for vestibular schwannoma treated with a 12 Gy prescription dose. Methods: We retrospectively reviewed our experience of vestibular schwannoma patients treated between September 2005 and December 2009. Two hundred patients were treated at a 12 Gy prescription dose; 80 had complete clinical and radiological follow-up for at least 24 months (median, 28.5 months). All treatment plans were reviewed for target volume and dosimetry characteristics; gradient index; homogeneity index, defined as the maximum dose in the treatment volume divided by the prescription dose; conformity index; brainstem; andmore » trigeminal nerve dose. All adverse radiation effects (ARE) were recorded. Because the intent of our study was to focus on the nonauditory adverse effects, hearing outcome was not evaluated in this study. Results: Twenty-seven (33.8%) patients developed ARE, 5 (6%) developed hydrocephalus, 10 (12.5%) reported new ataxia, 17 (21%) developed trigeminal dysfunction, 3 (3.75%) had facial weakness, and 1 patient developed hemifacial spasm. The development of edema within the pons was significantly associated with ARE (p = 0.001). On multivariate analysis, only target volume is a significant predictor of ARE (p = 0.001). There is a target volume threshold of 5 cm3, above which ARE are more likely. The treatment plan dosimetric characteristics are not associated with ARE, although the maximum dose to the 5th nerve is a significant predictor of trigeminal dysfunction, with a threshold of 9 Gy. The overall 2-year tumor control rate was 96%. Conclusions: Target volume is the most important predictor of adverse radiation effects, and we identified the significant treatment volume threshold to be 5 cm3. We also established through our series that the maximum tolerable dose to the 5th nerve is 9 Gy.« less

Monopolar Detection Thresholds Predict Spatial Selectivity of Neural Excitation in Cochlear Implants: Implications for Speech Recognition

PubMed Central

2016-01-01

The objectives of the study were to (1) investigate the potential of using monopolar psychophysical detection thresholds for estimating spatial selectivity of neural excitation with cochlear implants and to (2) examine the effect of site removal on speech recognition based on the threshold measure. Detection thresholds were measured in Cochlear Nucleus® device users using monopolar stimulation for pulse trains that were of (a) low rate and long duration, (b) high rate and short duration, and (c) high rate and long duration. Spatial selectivity of neural excitation was estimated by a forward-masking paradigm, where the probe threshold elevation in the presence of a forward masker was measured as a function of masker-probe separation. The strength of the correlation between the monopolar thresholds and the slopes of the masking patterns systematically reduced as neural response of the threshold stimulus involved interpulse interactions (refractoriness and sub-threshold adaptation), and spike-rate adaptation. Detection threshold for the low-rate stimulus most strongly correlated with the spread of forward masking patterns and the correlation reduced for long and high rate pulse trains. The low-rate thresholds were then measured for all electrodes across the array for each subject. Subsequently, speech recognition was tested with experimental maps that deactivated five stimulation sites with the highest thresholds and five randomly chosen ones. Performance with deactivating the high-threshold sites was better than performance with the subjects’ clinical map used every day with all electrodes active, in both quiet and background noise. Performance with random deactivation was on average poorer than that with the clinical map but the difference was not significant. These results suggested that the monopolar low-rate thresholds are related to the spatial neural excitation patterns in cochlear implant users and can be used to select sites for more optimal speech recognition performance. PMID:27798658

Role of nitric oxide in additive anticonvulsant effects of agmatine and morphine.

PubMed

Payandemehr, Borna; Rahimian, Reza; Bahremand, Arash; Ebrahimi, Ali; Saadat, Seyedehpariya; Moghaddas, Peiman; Fadakar, Kaveh; Derakhshanian, Hoda; Dehpour, Ahmad Reza

2013-06-13

The anticonvulsant effects of agmatine, an endogenous polyamine and a metabolite of l-arginine, have been shown in various experimental seizure models. Agmatine also potentiates the anti-seizure activity of morphine. The present study aimed to investigate a possible involvement of nitric oxide (NO) pathway in the protection by agmatine and morphine co-administration against pentylenetetrazole (PTZ) -induced seizure in male mice. To this end, the thresholds for the clonic seizures induced by the intravenous administration of PTZ, a GABA antagonist, were assessed. Intraperitoneal administration of morphine at lower dose (1mg/kg) increased the seizure threshold. Also intraperitoneal administration of agmatine (5 and 10mg/kg) increased the seizure threshold significantly. Combination of subeffective doses of morphine and agmatine led to potent anticonvulsant effects. Non-effective doses of morphine (0.1 and 0.5mg/kg) were able to induce anticonvulsant effects in mice pretreated with agmatine (3mg/kg). Concomitant administration of either the non-selective nitric oxide synthase (NOS) inhibitor L-NAME (1, 5mg/kg, i.p.) or the selective NOS inhibitor 7-NI (15, 30mg/kg, i.p.), with an ineffective combination of morphine (0.1mg/kg) plus agmatine (1mg/kg) produced significant anticonvulsant impacts. Moreover, the NO precursor, l-arginine (30, 60mg/kg, i.p.), inhibited the anticonvulsant action of agmatine (3mg/kg) plus morphine (0.5mg/kg) co-administration. Our results indicate that pretreatment of animals with agmatine enhances the anticonvulsant effects of morphine via a mechanism which may involve the NO pathway. Copyright © 2013 Elsevier Inc. All rights reserved.

Sucrose acceptance and different forms of associative learning of the honey bee (apis mellifera L.) in the field and laboratory.

PubMed

Mujagic, Samir; Sarkander, Jana; Erber, Barbara; Erber, Joachim

2010-01-01

The experiments analyze different forms of learning and 24-h retention in the field and in the laboratory in bees that accept sucrose with either low (/=30% or >/=50%) concentrations. In the field we studied color learning at a food site and at the hive entrance. In the laboratory olfactory conditioning of the proboscis extension response (PER) was examined. In the color learning protocol at a feeder, bees with low sucrose acceptance thresholds (/=50%). Retention after 24 h is significantly different between the two groups of bees and the choice reactions converge. Bees with low and high acceptance thresholds in the field show no differences in the sucrose sensitivity PER tests in the laboratory. Acceptance thresholds in the field are thus a more sensitive behavioral measure than PER responsiveness in the laboratory. Bees with low acceptance thresholds show significantly better acquisition and 24-h retention in olfactory learning in the laboratory compared to bees with high thresholds. In the learning protocol at the hive entrance bees learn without sucrose reward that a color cue signals an open entrance. In this experiment, bees with high sucrose acceptance thresholds showed significantly better learning and reversal learning than bees with low thresholds. These results demonstrate that sucrose acceptance thresholds affect only those forms of learning in which sucrose serves as the reward. The results also show that foraging behavior in the field is a good predictor for learning behavior in the field and in the laboratory.

Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Somatosensory and Laser Evoked Potentials

PubMed Central

Jones, Matthew D.; Taylor, Janet L.; Booth, John; Barry, Benjamin K.

2016-01-01

Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1–SEPs; Experiment 2–LEPs) by increased pressure pain thresholds at biceps brachii (24.3 and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p < 0.001) and first dorsal interosseous (18.8 and 21.5% increase in Experiment 1 and 2, respectively; both d > 0.57 and p < 0.001). In contrast, heat pain thresholds were not significantly different after exercise (forearm: 10.8% increase, d = 0.35, p = 0.10; hand: 3.6% increase, d = 0.06, p = 0.74). Contrasting effects of exercise on the amplitude of laser evoked potentials (14.6% decrease, d = −0.42, p = 0.004) and somatosensory evoked potentials (10.9% increase, d = −0.02, p = 1) were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = −0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = −0.32, p = 0.006). The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia. PMID:27965587

Effect of atorvastatin on progression of sensorineural hearing loss and tinnitus in the elderly: results of a prospective, randomized, double-blind clinical trial.

PubMed

Olzowy, Bernhard; Canis, Martin; Hempel, John-Martin; Mazurek, Birgit; Suckfüll, Markus

2007-06-01

To test whether the 3-hydroxy-3-methylglutaryl- coenzyme A reductase inhibitor atorvastatin can slow down the progression of presbycusis. Fifty patients 60- to 75-years-old with presbycusis and moderately elevated serum cholesterol. In a double-blind design, patients were randomly assigned to treatment with either atorvastatin (40 mg/d orally) or placebo. Pure-tone audiometry and tinnitus evaluation at enrolment and after 7 and 13 months. Development of hearing thresholds after 7 and 13 months showed no significant differences between the groups. Tinnitus score continuously improved in the atorvastatin group (34.8 at 7 and 27.6 at 13 mo), whereas it slightly deteriorated in the placebo group (24.8 at 7 and 26.8 at 13 mo). The effect on tinnitus was a tendency without statistic significance (p = 0.0833). Atorvastatin had no effect on the development of hearing thresholds, but resulted in a trend toward a relief of tinnitus.

Inspiratory muscle training with threshold or incentive spirometry: Which is the most effective?

PubMed

Paiva, Dulciane Nunes; Assmann, Laíse Bender; Bordin, Diogo Fanfa; Gass, Ricardo; Jost, Renan Trevisan; Bernardo-Filho, Mario; França, Rodrigo Alves; Cardoso, Dannuey Machado

2015-01-01

Inspiratory muscular training (IMT) increases the respiratory muscle strength, however, there is no data demonstrating its superiority over the incentive spirometry (IS) in doing so. Values of muscle strength after IMT (Threshold IMT(®)) and by the IS (Voldyne(®)) in healthy females was compared. Subjects (n=40) were randomly divided into control group (CG, n=14), IS group (ISG, n=13) and threshold group (TG, n=13). PImax was measured before (pre-IMT), at 15 and 30 days of IMT. There was an increase in PImax of the TG at 15 days (p<0.001) and 30 days of IMT (p<0.001). The same occurred with the ISG, which increased the PImax at 15 days (p<0.001) and 30 days of training (p<0.001). After 30 days of IMT, the TG presented a PImax which was significantly higher than ISG and the CG (p=0.045 and p<0.001, respectively). It can be concluded that IMT by threshold was more effective in increasing muscle strength than the Voldyne. Copyright © 2014 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L.U. All rights reserved.

Characterization of Renal Glucose Reabsorption in Response to Dapagliflozin in Healthy Subjects and Subjects With Type 2 Diabetes

PubMed Central

DeFronzo, Ralph A.; Hompesch, Marcus; Kasichayanula, Sreeneeranj; Liu, Xiaoni; Hong, Ying; Pfister, Marc; Morrow, Linda A.; Leslie, Bruce R.; Boulton, David W.; Ching, Agatha; LaCreta, Frank P.; Griffen, Steven C.

2013-01-01

OBJECTIVE To examine the effect of dapagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, on the major components of renal glucose reabsorption (decreased maximum renal glucose reabsorptive capacity [TmG], increased splay, and reduced threshold), using the pancreatic/stepped hyperglycemic clamp (SHC) technique. RESEARCH DESIGN AND METHODS Subjects with type 2 diabetes (n = 12) and matched healthy subjects (n = 12) underwent pancreatic/SHC (plasma glucose range 5.5–30.5 mmol/L) at baseline and after 7 days of dapagliflozin treatment. A pharmacodynamic model was developed to describe the major components of renal glucose reabsorption for both groups and then used to estimate these parameters from individual glucose titration curves. RESULTS At baseline, type 2 diabetic subjects had elevated TmG, splay, and threshold compared with controls. Dapagliflozin treatment reduced the TmG and splay in both groups. However, the most significant effect of dapagliflozin was a reduction of the renal threshold for glucose excretion in type 2 diabetic and control subjects. CONCLUSIONS The SGLT2 inhibitor dapagliflozin improves glycemic control in diabetic patients by reducing the TmG and threshold at which glucose is excreted in the urine. PMID:23735727

Underwater sound pressure variation and bottlenose dolphin (Tursiops truncatus) hearing thresholds in a small pool.

PubMed

Finneran, James J; Schlundt, Carolyn E

2007-07-01

Studies of underwater hearing are often hampered by the behavior of sound waves in small experimental tanks. At lower frequencies, tank dimensions are often not sufficient for free field conditions, resulting in large spatial variations of sound pressure. These effects may be mitigated somewhat by increasing the frequency bandwidth of the sound stimulus, so effects of multipath interference average out over many frequencies. In this study, acoustic fields and bottlenose dolphin (Tursiops truncatus) hearing thresholds were compared for pure tone and frequency modulated signals. Experiments were conducted in a vinyl-walled, seawater-filled pool approximately 3.7 x 6 x 1.5 m. Acoustic signals were pure tone and linear and sinusoidal frequency modulated tones with bandwidths/modulation depths of 1%, 2%, 5%, 10%, and 20%. Thirteen center frequencies were tested between 1 and 100 kHz. Acoustic fields were measured (without the dolphin present) at three water depths over a 60 x 65 cm grid with a 5-cm spacing. Hearing thresholds were measured using a behavioral response paradigm and up/down staircase technique. The use of FM signals significantly improved the sound field without substantially affecting the measured hearing thresholds.

The conventional tuning fork as a quantitative tool for vibration threshold.

PubMed

Alanazy, Mohammed H; Alfurayh, Nuha A; Almweisheer, Shaza N; Aljafen, Bandar N; Muayqil, Taim

2018-01-01

This study was undertaken to describe a method for quantifying vibration when using a conventional tuning fork (CTF) in comparison to a Rydel-Seiffer tuning fork (RSTF) and to provide reference values. Vibration thresholds at index finger and big toe were obtained in 281 participants. Spearman's correlations were performed. Age, weight, and height were analyzed for their covariate effects on vibration threshold. Reference values at the fifth percentile were obtained by quantile regression. The correlation coefficients between CTF and RSTF values at finger/toe were 0.59/0.64 (P = 0.001 for both). Among covariates, only age had a significant effect on vibration threshold. Reference values for CTF at finger/toe for the age groups 20-39 and 40-60 years were 7.4/4.9 and 5.8/4.6 s, respectively. Reference values for RSTF at finger/toe for the age groups 20-39 and 40-60 years were 6.9/5.5 and 6.2/4.7, respectively. CTF provides quantitative values that are as good as those provided by RSTF. Age-stratified reference data are provided. Muscle Nerve 57: 49-53, 2018. © 2017 Wiley Periodicals, Inc.

Analyzing threshold pressure limitations in microfluidic transistors for self-regulated microfluidic circuits.

PubMed

Kim, Sung-Jin; Yokokawa, Ryuji; Takayama, Shuichi

2012-12-03

This paper reveals a critical limitation in the electro-hydraulic analogy between a microfluidic membrane-valve (μMV) and an electronic transistor. Unlike typical transistors that have similar on and off threshold voltages, in hydraulic μMVs, the threshold pressures for opening and closing are significantly different and can change, even for the same μMVs depending on overall circuit design and operation conditions. We explain, in particular, how the negative values of the closing threshold pressures significantly constrain operation of even simple hydraulic μMV circuits such as autonomously switching two-valve microfluidic oscillators. These understandings have significant implications in designing self-regulated microfluidic devices.

The impact of threshold language assistance programming on the accessibility of mental health services for persons with limited English proficiency in the Medi-Cal setting.

PubMed

McClellan, Sean R; Wu, Frances M; Snowden, Lonnie R

2012-06-01

Title VI of the 1964 Civil Rights Act prohibits federal funds recipients from providing care to limited English proficiency (LEP) persons more limited in scope or lower in quality than care provided to others. In 1999, the California Department of Mental Health implemented a "threshold language access policy" to meet its Title VI obligations. Under this policy, Medi-Cal agencies must provide language assistance programming in a non-English language where a county's Medical population contains either 3000 residents or 5% speakers of that language. We examine the impact of threshold language policy-required language assistance programming on LEP persons' access to mental health services by analyzing the county-level penetration rate of services for Russian, Spanish, and Vietnamese speakers across 34 California counties, over 10 years of quarterly data. Exploiting a time series with nonequivalent control group study design, we studied this phenomena using linear regression with random county effects to account for trends over time. Threshold language policy-required assistance programming led to an immediate and significant increase in the penetration rate of mental health services for Russian (8.2, P < 0.01) and Vietnamese (3.3, P < 0.01) language speaking persons. Threshold language assistance programming was effective in increasing mental health access for Russian and Vietnamese, but not for Spanish-speaking LEP persons.

Correlation of gas exchange threshold and first muscle oxyhemoglobin inflection point with time-to-exhaustion during heavy-intensity exercise.

PubMed

Coquart, Jérémy B; Mucci, Patrick; L'hermette, Maxime; Chamari, Karim; Tourny, Claire; Garcin, Murielle

2017-03-01

The twofold aim of the study was to: 1) compare the gas exchange threshold (GET), the first oxyhemoglobin inflection point ([O2Hb]-T), and perceptual threshold as determined during an incremental exercise test, and 2) investigate the link between each threshold and time-to-exhaustion during heavy intensity exercise. Fourteen competitive cyclists performed an incremental exercise test to exhaustion on a cycloergometer to determine the different thresholds and peak workload (Wpeak). The participants then performed a sub-maximal constant workload test (90% Wpeak) to exhaustion to determine time-to-exhaustion. The thresholds were identified from: 1) the first breakpoint in the oxygen uptake vs. carbon dioxide output curve (GET), 2) the [O2Hb]-T, and 3) a rating of 13 in perceived exertion (perceptual threshold: RPE13-T). Oxygen uptake at the different thresholds was not significantly different (P>0.05). Moreover, GET and [O2Hb]-T were significantly correlated: 1) to each other (r≥0.79; P≤0.001), and 2) to time-to-exhaustion (r=0.81 and r=0.72, respectively; P<0.01). RPE13-T, however, was not significantly correlated with the time-to-exhaustion (P=0.148). The anaerobic threshold as identified from GET was concomitant to [O2Hb]-T. Both thresholds were correlated to time-to-exhaustion, and could therefore be used as a performance index in middle-duration events.

Relationship between behavioral and physiological spectral-ripple discrimination.

PubMed

Won, Jong Ho; Clinard, Christopher G; Kwon, Seeyoun; Dasika, Vasant K; Nie, Kaibao; Drennan, Ward R; Tremblay, Kelly L; Rubinstein, Jay T

2011-06-01

Previous studies have found a significant correlation between spectral-ripple discrimination and speech and music perception in cochlear implant (CI) users. This relationship could be of use to clinicians and scientists who are interested in using spectral-ripple stimuli in the assessment and habilitation of CI users. However, previous psychoacoustic tasks used to assess spectral discrimination are not suitable for all populations, and it would be beneficial to develop methods that could be used to test all age ranges, including pediatric implant users. Additionally, it is important to understand how ripple stimuli are processed in the central auditory system and how their neural representation contributes to behavioral performance. For this reason, we developed a single-interval, yes/no paradigm that could potentially be used both behaviorally and electrophysiologically to estimate spectral-ripple threshold. In experiment 1, behavioral thresholds obtained using the single-interval method were compared to thresholds obtained using a previously established three-alternative forced-choice method. A significant correlation was found (r = 0.84, p = 0.0002) in 14 adult CI users. The spectral-ripple threshold obtained using the new method also correlated with speech perception in quiet and noise. In experiment 2, the effect of the number of vocoder-processing channels on the behavioral and physiological threshold in normal-hearing listeners was determined. Behavioral thresholds, using the new single-interval method, as well as cortical P1-N1-P2 responses changed as a function of the number of channels. Better behavioral and physiological performance (i.e., better discrimination ability at higher ripple densities) was observed as more channels added. In experiment 3, the relationship between behavioral and physiological data was examined. Amplitudes of the P1-N1-P2 "change" responses were significantly correlated with d' values from the single-interval behavioral procedure. Results suggest that the single-interval procedure with spectral-ripple phase inversion in ongoing stimuli is a valid approach for measuring behavioral or physiological spectral resolution.

Effects of whole body vibration on motor unit recruitment and threshold

PubMed Central

Woledge, Roger C.; Martin, Finbarr C.; Newham, Di J.

2012-01-01

Whole body vibration (WBV) has been suggested to elicit reflex muscle contractions but this has never been verified. We recorded from 32 single motor units (MU) in the vastus lateralis of 7 healthy subjects (34 ± 15.4 yr) during five 1-min bouts of WBV (30 Hz, 3 mm peak to peak), and the vibration waveform was also recorded. Recruitment thresholds were recorded from 38 MUs before and after WBV. The phase angle distribution of all MUs during WBV was nonuniform (P < 0.001) and displayed a prominent peak phase angle of firing. There was a strong linear relationship (r = −0.68, P < 0.001) between the change in recruitment threshold after WBV and average recruitment threshold; the lowest threshold MUs increased recruitment threshold (P = 0.008) while reductions were observed in the higher threshold units (P = 0.031). We investigated one possible cause of changed thresholds. Presynaptic inhibition in the soleus was measured in 8 healthy subjects (29 ± 4.6 yr). A total of 30 H-reflexes (stimulation intensity 30% Mmax) were recorded before and after WBV: 15 conditioned by prior stimulation (60 ms) of the antagonist and 15 unconditioned. There were no significant changes in the relationship between the conditioned and unconditioned responses. The consistent phase angle at which each MU fired during WBV indicates the presence of reflex muscle activity similar to the tonic vibration reflex. The varying response in high- and low-threshold MUs may be due to the different contributions of the mono- and polysynaptic pathways but not presynaptic inhibition. PMID:22096119

Effects of whole body vibration on motor unit recruitment and threshold.

PubMed

Pollock, Ross D; Woledge, Roger C; Martin, Finbarr C; Newham, Di J

2012-02-01

Whole body vibration (WBV) has been suggested to elicit reflex muscle contractions but this has never been verified. We recorded from 32 single motor units (MU) in the vastus lateralis of 7 healthy subjects (34 ± 15.4 yr) during five 1-min bouts of WBV (30 Hz, 3 mm peak to peak), and the vibration waveform was also recorded. Recruitment thresholds were recorded from 38 MUs before and after WBV. The phase angle distribution of all MUs during WBV was nonuniform (P < 0.001) and displayed a prominent peak phase angle of firing. There was a strong linear relationship (r = -0.68, P < 0.001) between the change in recruitment threshold after WBV and average recruitment threshold; the lowest threshold MUs increased recruitment threshold (P = 0.008) while reductions were observed in the higher threshold units (P = 0.031). We investigated one possible cause of changed thresholds. Presynaptic inhibition in the soleus was measured in 8 healthy subjects (29 ± 4.6 yr). A total of 30 H-reflexes (stimulation intensity 30% Mmax) were recorded before and after WBV: 15 conditioned by prior stimulation (60 ms) of the antagonist and 15 unconditioned. There were no significant changes in the relationship between the conditioned and unconditioned responses. The consistent phase angle at which each MU fired during WBV indicates the presence of reflex muscle activity similar to the tonic vibration reflex. The varying response in high- and low-threshold MUs may be due to the different contributions of the mono- and polysynaptic pathways but not presynaptic inhibition.

Effects of passive and active movement on vibrotactile detection thresholds of the Pacinian channel and forward masking.

PubMed

Yıldız, Mustafa Z; Toker, İpek; Özkan, Fatma B; Güçlü, Burak

2015-01-01

We investigated the gating effect of passive and active movement on the vibrotactile detection thresholds of the Pacinian (P) psychophysical channel and forward masking. Previous work on gating mostly used electrocutaneous stimulation and did not allow focusing on tactile submodalities. Ten healthy adults participated in our study. Passive movement was achieved by swinging a platform, on which the participant's stimulated hand was attached, manually by a trained operator. The root-mean-square value of the movement speed was kept in a narrow range (slow: 10-20 cm/s, fast: 50-60 cm/s). Active movement was performed by the participant him-/herself using the same apparatus. The tactile stimuli consisted of 250-Hz sinusoidal mechanical vibrations, which were generated by a shaker mounted on the movement platform and applied to the middle fingertip. In the forward-masking experiments, a high-level masking stimulus preceded the test stimulus. Each movement condition was tested separately in a two-interval forced-choice detection task. Both passive and active movement caused a robust gating effect, that is, elevation of thresholds, in the fast speed range. Statistically significant change of thresholds was not found in slow movement conditions. Passive movement yielded higher thresholds than those measured during active movement, but this could not be confirmed statistically. On the other hand, the effect of forward masking was approximately constant as the movement condition varied. These results imply that gating depends on both peripheral and central factors in the P channel. Active movement may have some facilitatory role and produce less gating. Additionally, the results support the hypothesis regarding a critical speed for gating, which may be relevant for daily situations involving vibrations transmitted through grasped objects and for manual exploration.

Threshold conditions for integrated pest management models with pesticides that have residual effects.

PubMed

Tang, Sanyi; Liang, Juhua; Tan, Yuanshun; Cheke, Robert A

2013-01-01

Impulsive differential equations (hybrid dynamical systems) can provide a natural description of pulse-like actions such as when a pesticide kills a pest instantly. However, pesticides may have long-term residual effects, with some remaining active against pests for several weeks, months or years. Therefore, a more realistic method for modelling chemical control in such cases is to use continuous or piecewise-continuous periodic functions which affect growth rates. How to evaluate the effects of the duration of the pesticide residual effectiveness on successful pest control is key to the implementation of integrated pest management (IPM) in practice. To address these questions in detail, we have modelled IPM including residual effects of pesticides in terms of fixed pulse-type actions. The stability threshold conditions for pest eradication are given. Moreover, effects of the killing efficiency rate and the decay rate of the pesticide on the pest and on its natural enemies, the duration of residual effectiveness, the number of pesticide applications and the number of natural enemy releases on the threshold conditions are investigated with regard to the extent of depression or resurgence resulting from pulses of pesticide applications and predator releases. Latin Hypercube Sampling/Partial Rank Correlation uncertainty and sensitivity analysis techniques are employed to investigate the key control parameters which are most significantly related to threshold values. The findings combined with Volterra's principle confirm that when the pesticide has a strong effect on the natural enemies, repeated use of the same pesticide can result in target pest resurgence. The results also indicate that there exists an optimal number of pesticide applications which can suppress the pest most effectively, and this may help in the design of an optimal control strategy.

Impact of co-administration of oxycodone and smoked cannabis on analgesia and abuse liability.

PubMed

Cooper, Ziva D; Bedi, Gillinder; Ramesh, Divya; Balter, Rebecca; Comer, Sandra D; Haney, Margaret

2018-02-05

Cannabinoids combined with opioids produce synergistic antinociceptive effects, decreasing the lowest effective antinociceptive opioid dose (i.e., opioid-sparing effects) in laboratory animals. Although pain patients report greater analgesia when cannabis is used with opioids, no placebo-controlled studies have assessed the direct effects of opioids combined with cannabis in humans or the impact of the combination on abuse liability. This double-blind, placebo-controlled, within-subject study determined if cannabis enhances the analgesic effects of low dose oxycodone using a validated experimental model of pain and its effects on abuse liability. Healthy cannabis smokers (N = 18) were administered oxycodone (0, 2.5, and 5.0 mg, PO) with smoked cannabis (0.0, 5.6% Δ 9 tetrahydrocannabinol [THC]) and analgesia was assessed using the Cold-Pressor Test (CPT). Participants immersed their hand in cold water (4 °C); times to report pain (pain threshold) and withdraw the hand from the water (pain tolerance) were recorded. Abuse-related effects were measured and effects of oxycodone on cannabis self-administration were determined. Alone, 5.0 mg oxycodone increased pain threshold and tolerance (p ≤ 0.05). Although active cannabis and 2.5 mg oxycodone alone failed to elicit analgesia, combined they increased pain threshold and tolerance (p ≤ 0.05). Oxycodone did not increase subjective ratings associated with cannabis abuse, nor did it increase cannabis self-administration. However, the combination of 2.5 mg oxycodone and active cannabis produced small, yet significant, increases in oxycodone abuse liability (p ≤ 0.05). Cannabis enhances the analgesic effects of sub-threshold oxycodone, suggesting synergy, without increases in cannabis's abuse liability. These findings support future research into the therapeutic use of opioid-cannabinoid combinations for pain.

Thermal detection thresholds in 5-year-old preterm born children; IQ does matter.

PubMed

de Graaf, Joke; Valkenburg, Abraham J; Tibboel, Dick; van Dijk, Monique

2012-07-01

Experiencing pain at newborn age may have consequences on one's somatosensory perception later in life. Children's perception for cold and warm stimuli may be determined with the Thermal Sensory Analyzer (TSA) device by two different methods. This pilot study in 5-year-old children born preterm aimed at establishing whether the TSA method of limits, which is dependent of reaction time, and the method of levels, which is independent of reaction time, would yield different cold and warm detection thresholds. The second aim was to establish possible associations between intellectual ability and the detection thresholds obtained with either method. A convenience sample was drawn from the participants in an ongoing 5-year follow-up study of a randomized controlled trial on effects of morphine during mechanical ventilation. Thresholds were assessed using both methods and statistically compared. Possible associations between the child's intelligence quotient (IQ) and threshold levels were analyzed. The method of levels yielded more sensitive thresholds than did the method of limits, i.e. mean (SD) cold detection thresholds: 30.3 (1.4) versus 28.4 (1.7) (Cohen'sd=1.2, P=0.001) and warm detection thresholds; 33.9 (1.9) versus 35.6 (2.1) (Cohen's d=0.8, P=0.04). IQ was statistically significantly associated only with the detection thresholds obtained with the method of limits (cold: r=0.64, warm: r=-0.52). The TSA method of levels, is to be preferred over the method of limits in 5-year-old preterm born children, as it establishes more sensitive detection thresholds and is independent of IQ. Copyright © 2011 Elsevier Ltd. All rights reserved.

Exhibition of stochastic resonance in vestibular tilt motion perception.

PubMed

Galvan-Garza, R C; Clark, T K; Mulavara, A P; Oman, C M

2018-04-03

Stochastic Resonance (SR) is a phenomenon broadly described as "noise benefit". The application of subsensory electrical Stochastic Vestibular Stimulation (SVS) via electrodes behind each ear has been used to improve human balance and gait, but its effect on motion perception thresholds has not been examined. This study investigated the capability of subsensory SVS to reduce vestibular motion perception thresholds in a manner consistent with a characteristic bell-shaped SR curve. We measured upright, head-centered, roll tilt Direction Recognition (DR) thresholds in the dark in 12 human subjects with the application of wideband 0-30 Hz SVS ranging from ±0-700 μA. To conservatively assess if SR was exhibited, we compared the proportions of both subjective and statistical SR exhibition in our experimental data to proportions of SR exhibition in multiple simulation cases with varying underlying SR behavior. Analysis included individual and group statistics. As there is not an established mathematical definition, three humans subjectively judged that SR was exhibited in 78% of subjects. "Statistically significant SR exhibition", which additionally required that a subject's DR threshold with SVS be significantly lower than baseline (no SVS), was present in 50% of subjects. Both percentages were higher than simulations suggested could occur simply by chance. For SR exhibitors, defined by subjective or statistically significant criteria, the mean DR threshold improved by -30% and -39%, respectively. The largest individual improvement was -47%. At least half of the subjects were better able to perceive passive body motion with the application of subsensory SVS. This study presents the first conclusive demonstration of SR in vestibular motion perception. Copyright © 2018 Elsevier Inc. All rights reserved.

TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION AT BOTH HIGH AND LOW FREQUENCIES ACTIVATES VENTROLATERAL PERIAQUEDUCTAL GREY TO DECREASE MECHANICAL HYPERALGESIA IN ARTHRITIC RATS

PubMed Central

Desantana, J. M.; Da Silva, L. F. S.; De Resende, M. A.; Sluka, K. A.

2014-01-01

Transcutaneous electric nerve stimulation (TENS) is widely used for the treatment of pain. TENS produces an opioid-mediated antinociception that utilizes the rostroventromedial medulla (RVM). Similarly, antinociception evoked from the periaqueductal grey (PAG) is opioid-mediated and includes a relay in the RVM. Therefore, we investigated whether the ventrolateral or dorsolateral PAG mediates antinociception produced by TENS in rats. Paw and knee joint mechanical withdrawal thresholds were assessed before and after knee joint inflammation (3% kaolin/carrageenan), and after TENS stimulation (active or sham). Cobalt chloride (CoCl2; 5 mM) or vehicle was microinjected into the ventrolateral periaqueductal grey (vlPAG) or dorsolateral periaqueductal grey (dlPAG) prior to treatment with TENS. Either high (100 Hz) or low (4 Hz) frequency TENS was then applied to the inflamed knee for 20 min. Active TENS significantly increased withdrawal thresholds of the paw and knee joint in the group microinjected with vehicle when compared to thresholds prior to TENS (P<0.001) or to sham TENS (P<0.001). The increases in withdrawal thresholds normally observed after TENS were prevented by microinjection of CoCl2 into the vlPAG, but not the dlPAG prior to TENS and were significantly lower than controls treated with TENS (P<0.001). In a separate group of animals, microinjection of CoCl2 into the vlPAG temporarily reversed the decreased mechanical withdrawal threshold suggesting a role for the vlPAG in the facilitation of joint pain. No significant difference was observed for dlPAG. We hypothesize that the effects of TENS are mediated through the vlPAG that sends projections through the RVM to the spinal cord to produce an opioid-mediated analgesia. PMID:19576962

Lubiprostone does not influence visceral pain thresholds in patients with irritable bowel syndrome.

PubMed

Whitehead, W E; Palsson, O S; Gangarosa, L; Turner, M; Tucker, J

2011-10-01

In clinical trials, lubiprostone reduced the severity of abdominal pain. The primary aim was to determine whether lubiprostone raises the threshold for abdominal pain induced by intraluminal balloon distention. A secondary aim was to determine whether changes in pain sensitivity influence clinical pain independently of changes in transit time. Sixty-two patients with irritable bowel syndrome with constipation (IBS-C) participated in an 8-week cross-over study. All subjects completed a 14-day baseline ending with a barostat test of pain and urge sensory thresholds. Half, randomly selected, then received 48 μg day(-1) of lubiprostone for 14 days ending with a pain sensitivity test and a Sitzmark test of transit time. This was followed by a 14-day washout and then a crossover to 14 days of placebo with tests of pain sensitivity and transit time. The other half of the subjects received placebo before lubiprostone. All kept symptom diaries. Stools were significantly softer when taking lubiprostone compared to placebo (Bristol Stool scores 4.20 vs 3.44, P < 0.001). However, thresholds for pain (17.36 vs 17.83 mmHg, lubiprostone vs placebo) and urgency to defecate (14.14 vs 14.53 mmHg) were not affected by lubiprostone. Transit time was not significantly different between lubiprostone and placebo (51.27 vs 51.81 h), and neither pain sensitivity nor transit time was a significant predictor of clinical pain. Lubiprostone has no effect on visceral sensory thresholds. The reductions in clinical pain that occur while taking lubiprostone appear to be secondary to changes in stool consistency. © 2011 Blackwell Publishing Ltd.

Diurnal Variation of Sweet Taste Recognition Thresholds Is Absent in Overweight and Obese Humans

PubMed Central

Sanematsu, Keisuke; Nakamura, Yuki; Nomura, Masatoshi; Shigemura, Noriatsu; Ninomiya, Yuzo

2018-01-01

Sweet taste thresholds are positively related to plasma leptin levels in normal weight humans: both show parallel diurnal variations and associations with postprandial glucose and insulin rises. Here, we tested whether this relationship also exists in overweight and obese (OW/Ob) individuals with hyperleptinemia. We tested 36 Japanese OW/Ob subjects (body mass index (BMI) > 25 kg/m2) for recognition thresholds for various taste stimuli at seven different time points from 8:00 a.m. to 10:00 p.m. using the staircase methodology, and measured plasma leptin, insulin, and blood glucose levels before each taste threshold measurement. We also used the homeostatic model assessment of insulin resistance (HOMA-IR) to evaluate insulin resistance. The results demonstrated that, unlike normal weight subjects, OW/Ob subjects showed no significant diurnal variations in the recognition thresholds for sweet stimuli but exhibited negative associations between the diurnal variations of both leptin and sweet recognition thresholds and the HOMA-IR scores. These findings suggest that in OW/Ob subjects, the basal leptin levels (~20 ng/mL) may already exceed leptin’s effective concentration for the modulation of sweet sensitivity and that this leptin resistance-based attenuation of the diurnal variations of the sweet taste recognition thresholds may also be indirectly linked to insulin resistance in OW/Ob subjects. PMID:29498693

Thermosensitivity is reduced during fever induced by Staphylococcus aureus cells walls in rabbits.

PubMed

Tøien, Ø; Mercer, J B

1996-05-01

Thermosensitivity (TS) and threshold core temperature for metabolic cold defence were determined in six conscious rabbits before, and at seven different times after i.v. injection of killed Staphylococcus aureus (8 x 10(7) or 2 x 10(7) cell walls x kg(-1)) by exposure to short periods (5-10 min) of body cooling. Heat was extracted with a chronically implanted intravascular heat exchanger. TS was calculated by regression of metabolic heat production (M) and core temperature, as indicated by hypothalamic temperature. Threshold for cold defence (shivering threshold) was calculated as the core temperature at which the thermosensitivity line crossed preinjection resting M. The shivering thresholds followed the shape of the fever response. TS was significantly reduced (up to 49%) during the time course of fever induced by the highest dose of pyrogen only. At both high and low doses of pyrogen TS correlated negatively with shivering threshold (r = 0.66 and 0.79 respectively) with similar slopes. The reduction in TS during fever was thus associated with the increase in shivering threshold resulting from the pyrogen injection and not by the dose of pyrogen. Model considerations indicate, however, that changes in sensitivity of the thermosensory input to the hypothalamic controller may affect threshold changes but cause negligible TS changes. It is more likely that the reduction in TS is effected in the specific hypothalamic effector pathways.

Effects of underwater noise on auditory sensitivity of a cyprinid fish.

PubMed

Scholik, A R; Yan, H Y

2001-02-01

The ability of a fish to interpret acoustic information in its environment is crucial for its survival. Thus, it is important to understand how underwater noise affects fish hearing. In this study, the fathead minnow (Pimephales promelas) was used to examine: (1) the immediate effects of white noise exposure (0.3-4.0 kHz, 142 dB re: 1 microPa) on auditory thresholds and (2) recovery after exposure. Audiograms were measured using the auditory brainstem response protocol and compared to baseline audiograms of fathead minnows not exposed to noise. Immediately after exposure to 24 h of white noise, five out of the eight frequencies tested showed a significantly higher threshold compared to the baseline fish. Recovery was found to depend on both duration of noise exposure and auditory frequency. These results support the hypothesis that the auditory threshold of the fathead minnow can be altered by white noise, especially in its most sensitive hearing range (0.8-2.0 kHz), and provide evidence that these effects can be long term (>14 days).

Cocaine enhances resistance to extinction of responding for brain-stimulation reward in adult prenatally stressed rats.

PubMed

Gao, Shuibo; Suenaga, Toshiko; Oki, Yutaka; Yukie, Masao; Nakahara, Daiichiro

2011-10-01

The present experiment assessed whether prenatal stress (PS) can alter the ability of acute and chronic cocaine administration to increase and decrease the rewarding effectiveness of the medial forebrain bundle (MFB) using intracranial self-stimulation (ICSS), and also whether PS can affect the extinction of the MFB stimulation response. Adult male offspring of female rats that received PS or no PS (nPS) were implanted with MFB stimulating electrodes, and were then tested in ICSS paradigms. In both nPS and PS offspring, acute cocaine injection decreased ICSS thresholds dose-dependently. However, the threshold-lowering effects at any dose were not significantly different between groups. There was also no group-difference in the threshold-elevating effects of chronic cocaine administration. Nevertheless, chronically drug-administered PS rats exhibited a resistance to the extinguishing of the response for brain-stimulation reward when acutely treated with cocaine, as compared to extinction without cocaine treatment. The results suggest that PS may weaken the ability for response inhibition under cocaine loading in male adult offspring. Copyright © 2011 Elsevier B.V. All rights reserved.

A null model for Pearson coexpression networks.

PubMed

Gobbi, Andrea; Jurman, Giuseppe

2015-01-01

Gene coexpression networks inferred by correlation from high-throughput profiling such as microarray data represent simple but effective structures for discovering and interpreting linear gene relationships. In recent years, several approaches have been proposed to tackle the problem of deciding when the resulting correlation values are statistically significant. This is most crucial when the number of samples is small, yielding a non-negligible chance that even high correlation values are due to random effects. Here we introduce a novel hard thresholding solution based on the assumption that a coexpression network inferred by randomly generated data is expected to be empty. The threshold is theoretically derived by means of an analytic approach and, as a deterministic independent null model, it depends only on the dimensions of the starting data matrix, with assumptions on the skewness of the data distribution compatible with the structure of gene expression levels data. We show, on synthetic and array datasets, that the proposed threshold is effective in eliminating all false positive links, with an offsetting cost in terms of false negative detected edges.

Voluntary Running-Wheel Exercise Decreases the Threshold for Rewarding Intracranial Self-Stimulation

PubMed Central

Morris, Michael J.; Na, Elisa S.; Johnson, Alan Kim

2015-01-01

Physical exercise has mood-enhancing and antidepressant properties although the mechanisms underlying these effects are not known. The present experiment investigated the effects of prolonged access to a running wheel on electrical self-stimulation of the lateral hypothalamus (LHSS), a measure of hedonic state, in rats. Rats with continuous voluntary access to a running wheel for either 2 or 5 weeks exhibited dramatic leftward shifts in the effective current 50 (ECu50; current value that supports half of maximum responding) of their LHSS current-response functions compared to their baselines, indicating a decrease in reward threshold, whereas control rats current-response functions after 2 or 5 weeks were not significantly different from baseline. An inverse correlation existed between the change in ECu50 from baseline and the amount an animal had run in the day prior to LHSS testing, indicating that animals that exhibited higher levels of running showed a more robust decrease in LHSS threshold. We conclude that long-term voluntary exercise increases sensitivity to rewarding stimuli, which may contribute to its antidepressant properties. PMID:22845707

Voluntary running-wheel exercise decreases the threshold for rewarding intracranial self-stimulation.

PubMed

Morris, Michael J; Na, Elisa S; Johnson, Alan Kim

2012-08-01

Physical exercise has mood-enhancing and antidepressant properties although the mechanisms underlying these effects are not known. The present experiment investigated the effects of prolonged access to a running wheel on electrical self-stimulation of the lateral hypothalamus (LHSS), a measure of hedonic state, in rats. Rats with continuous voluntary access to a running wheel for either 2 or 5 weeks exhibited dramatic leftward shifts in the effective current 50 (ECu50; current value that supports half of maximum responding) of their LHSS current-response functions compared to their baselines, indicating a decrease in reward threshold, whereas control rats current-response functions after 2 or 5 weeks were not significantly different from baseline. An inverse correlation existed between the change in ECu50 from baseline and the amount an animal had run in the day prior to LHSS testing, indicating that animals that exhibited higher levels of running showed a more robust decrease in LHSS threshold. We conclude that long-term voluntary exercise increases sensitivity to rewarding stimuli, which may contribute to its antidepressant properties.

The Irish Cost-Effectiveness Threshold: Does it Support Rational Rationing or Might it Lead to Unintended Harm to Ireland's Health System?

PubMed

O'Mahony, James F; Coughlan, Diarmuid

2016-01-01

Ireland is one of the few countries worldwide to have an explicit cost-effectiveness threshold. In 2012, an agreement between government and the pharmaceutical industry that provided substantial savings on existing medications set the threshold at €45,000/quality-adjusted life-year (QALY). This replaced a previously unofficial threshold of €20,000/QALY. According to the agreement, drugs within the threshold will be granted reimbursement, whereas those exceeding it may still be approved following further negotiation. A number of drugs far exceeding the threshold have been approved recently. The agreement only applies to pharmaceuticals. There are four reasons for concern regarding Ireland's threshold. The absence of an explicit threshold for non-drug interventions leaves it unclear if there is parity in willingness to pay across all interventions. As the threshold resembles a price floor rather than a ceiling, in principle it only offers a weak barrier to cost-ineffective interventions. It has no empirical basis. Finally, it is probably too high given recent estimates of a threshold for the UK based on the cost effectiveness of services forgone of approximately £13,000/QALY. An excessive threshold risks causing the Irish health system unintended harm. The lack of an empirically informed threshold means the policy recommendations of cost-effectiveness analysis cannot be considered as fully evidence- based rational rationing. Policy makers should consider these issues and recent Irish legislation that defined cost effectiveness in terms of the opportunity cost of services forgone when choosing what threshold to apply once the current industry agreement expires at the end of 2015

The effects of a repeated dose of a recombinant humanized anti-cocaine monoclonal antibody on cocaine self-administration in rats.

PubMed

Wetzel, Hanna N; Tsibulsky, Vladimir L; Norman, Andrew B

2016-11-01

Immunotherapy has shown potential as a treatment for cocaine abuse. The humanized recombinant anti-cocaine monoclonal antibody (mAb) with the preclinical designation h2E2 has been shown to decrease cocaine concentrations in the brain in rats, but its effects on cocaine self-administration behavior have never been tested. The amount of cocaine needed to reinstate self-administration behavior (priming threshold) was calculated and the inter-injection intervals at unit doses of 0.3μmol/kg and 3μmol/kg during maintained self-administration were measured over a five-week baseline period. Rats trained to self-administer cocaine were infused with two doses of h2E2 (120mg/kg i.v.) 35days apart. Priming threshold and inter-injection intervals were measured for 35days after both injections. After both injections of h2E2, priming thresholds were significantly increased (3-fold) compared to expected baseline and then gradually declined over 35days. A significant decrease (15-33%) in inter-injection intervals during maintained self-administration was also observed following both h2E2 infusions at the lower dose, and after the first injection at the higher dose. No significant decreases in body weight were observed after either injection, indicating a lack of toxicity following a second injection. These data predict that the safety and effectiveness of h2E2 will be maintained after multiple treatments of this potential immunotherapy for cocaine abuse. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The Anti-(+)-Methamphetamine Monoclonal Antibody mAb7F9 Attenuates Acute (+)-Methamphetamine Effects on Intracranial Self-Stimulation in Rats

PubMed Central

Harris, Andrew C.; LeSage, Mark G.; Shelley, David; Perry, Jennifer L.; Pentel, Paul R.; Owens, S. Michael

2015-01-01

Passive immunization with monoclonal antibodies (mAbs) against (+)-methamphetamine (METH) is being evaluated for the treatment of METH addiction. A human/mouse chimeric form of the murine anti-METH mAb7F9 has entered clinical trials. This study examined the effects of murine mAb7F9 on certain addiction-related behavioral effects of METH in rats as measured using intracranial self-stimulation (ICSS). Initial studies indicated that acute METH (0.1-0.56 mg/kg, s.c.) lowered the minimal (threshold) stimulation intensity that maintained ICSS. METH (0.3 mg/kg, s.c.) also blocked elevations in ICSS thresholds (anhedonia-like behavior) during spontaneous withdrawal from a chronic METH infusion (10 mg/kg/day x 7 days). In studies examining effects of i.v. pretreatment with mAb7F9 (at 30, 100, or 200 mg/kg), 200 mg/kg blocked the ability of an initial injection of METH (0.3 mg/kg, s.c.) to reduce baseline ICSS thresholds, but was less capable of attenuating the effect of subsequent daily injections of METH. MAb7F9 (200 mg/kg) also produced a small but significant reduction in the ability of METH (0.3 mg/kg, s.c.) to reverse METH withdrawal-induced elevations in ICSS thresholds. These studies demonstrate that mAb7F9 can partially attenuate some addiction-related effects of acute METH in an ICSS model, and provide some support for the therapeutic potential of mAb7F9 for the treatment of METH addiction. PMID:25742165

Optimal Stimulus Amplitude for Vestibular Stochastic Stimulation to Improve Sensorimotor Function

NASA Technical Reports Server (NTRS)

Goel, R.; Kofman, I.; DeDios, Y. E.; Jeevarajan, J.; Stepanyan, V.; Nair, M.; Congdon, S.; Fregia, M.; Cohen, H.; Bloomberg, J. J.;

Spontaneous Trigeminal Allodynia in Rats: A Model of Primary Headache

PubMed Central

Oshinsky, Michael L.; Sanghvi, Menka M.; Maxwell, Christina R.; Gonzalez, Dorian; Spangenberg, Rebecca J.; Cooper, Marnie; Silberstein, Stephen D.

2014-01-01

Animal models are essential for studying the pathophysiology of headache disorders and as a screening tool for new therapies. Most animal models modify a normal animal in an attempt to mimic migraine symptoms. They require manipulation to activate the trigeminal nerve or dural nociceptors. At best, they are models of secondary headache. No existing model can address the fundamental question: How is a primary headache spontaneously initiated? In the process of obtaining baseline periorbital von Frey thresholds in a wild-type Sprague-Dawley rat, we discovered a rat with spontaneous episodic trigeminal allodynia (manifested by episodically changing periorbital pain threshold). Subsequent mating showed that the trait is inherited. Animals with spontaneous trigeminal allodynia allow us to study the pathophysiology of primary recurrent headache disorders. To validate this as a model for migraine, we tested the effects of clinically proven acute and preventive migraine treatments on spontaneous changes in rat periorbital sensitivity. Sumatriptan, ketorolac, and dihydroergotamine temporarily reversed the low periorbital pain thresholds. Thirty days of chronic valproic acid treatment prevented spontaneous changes in trigeminal allodynia. After discontinuation, the rats returned to their baseline of spontaneous episodic threshold changes. We also tested the effects of known chemical human migraine triggers. On days when the rats did not have allodynia and showed normal periorbital von Frey thresholds, glycerol trinitrate and calcitonin gene related peptide induced significant decreases in the periorbital pain threshold. This model can be used as a predictive model for drug development and for studies of putative biomarkers for headache diagnosis and treatment. PMID:22963523

Assessing Regional and Interspecific Variation in Threshold Responses of Forest Breeding Birds through Broad Scale Analyses

PubMed Central

van der Hoek, Yntze; Renfrew, Rosalind; Manne, Lisa L.

2013-01-01

Background Identifying persistence and extinction thresholds in species-habitat relationships is a major focal point of ecological research and conservation. However, one major concern regarding the incorporation of threshold analyses in conservation is the lack of knowledge on the generality and transferability of results across species and regions. We present a multi-region, multi-species approach of modeling threshold responses, which we use to investigate whether threshold effects are similar across species and regions. Methodology/Principal Findings We modeled local persistence and extinction dynamics of 25 forest-associated breeding birds based on detection/non-detection data, which were derived from repeated breeding bird atlases for the state of Vermont. We did not find threshold responses to be particularly well-supported, with 9 species supporting extinction thresholds and 5 supporting persistence thresholds. This contrasts with a previous study based on breeding bird atlas data from adjacent New York State, which showed that most species support persistence and extinction threshold models (15 and 22 of 25 study species respectively). In addition, species that supported a threshold model in both states had associated average threshold estimates of 61.41% (SE = 6.11, persistence) and 66.45% (SE = 9.15, extinction) in New York, compared to 51.08% (SE = 10.60, persistence) and 73.67% (SE = 5.70, extinction) in Vermont. Across species, thresholds were found at 19.45–87.96% forest cover for persistence and 50.82–91.02% for extinction dynamics. Conclusions/Significance Through an approach that allows for broad-scale comparisons of threshold responses, we show that species vary in their threshold responses with regard to habitat amount, and that differences between even nearby regions can be pronounced. We present both ecological and methodological factors that may contribute to the different model results, but propose that regardless of the reasons behind these differences, our results merit a warning that threshold values cannot simply be transferred across regions or interpreted as clear-cut targets for ecosystem management and conservation. PMID:23409106

An Evaluation of Performance Thresholds in Nursing Home Pay-for-Performance.

PubMed

Werner, Rachel M; Skira, Meghan; Konetzka, R Tamara

2016-12-01

Performance thresholds are commonly used in pay-for-performance (P4P) incentives, where providers receive a bonus payment for achieving a prespecified target threshold but may produce discontinuous incentives, with providers just below the threshold having the strongest incentive to improve and providers either far below or above the threshold having little incentive. We investigate the effect of performance thresholds on provider response in the setting of nursing home P4P. The Minimum Data Set (MDS) and Online Survey, Certification, and Reporting (OSCAR) datasets. Difference-in-differences design to test for changes in nursing home performance in three states that implemented threshold-based P4P (Colorado, Georgia, and Oklahoma) versus three comparator states (Arizona, Tennessee, and Arkansas) between 2006 and 2009. We find that those farthest below the threshold (i.e., the worst-performing nursing homes) had the largest improvements under threshold-based P4P while those farthest above the threshold worsened. This effect did not vary with the percentage of Medicaid residents in a nursing home. Threshold-based P4P may provide perverse incentives for nursing homes above the performance threshold, but we do not find evidence to support concerns about the effects of performance thresholds on low-performing nursing homes. © Health Research and Educational Trust.

Dynamic energy budget as a basis to model population-level effects of zinc-spiked sediments in the gastropod Valvata piscinalis.

PubMed

Ducrot, Virginie; Péry, Alexandre R R; Mons, Raphaël; Quéau, Hervé; Charles, Sandrine; Garric, Jeanne

2007-08-01

This paper presents original toxicity test designs and mathematical models that may be used to assess the deleterious effects of toxicants on Valvata piscinalis (Mollusca, Gastropoda). Results obtained for zinc, used as a reference toxicant, are presented. The feeding behavior, juvenile survival, growth, age at puberty, onset of reproduction, number of breedings during the life cycle, and fecundity were significantly altered when the snails were exposed to zinc-spiked sediments. Dynamic energy budget models (DEBtox) adequately predicted the effects of zinc on the V. piscinalis life cycle. They also provided estimates for lifecycle parameters that were used to parameterize a demographic model, based on a Z-transformed life-cycle graph. The effect threshold for the population growth rate (lambda) was estimated at 259 mg/kg dry sediment of zinc, showing that significant changes in abundance may occur at environmental concentrations. Significant effects occurring just above this threshold value were mainly caused by the severe impairment of reproductive endpoints. Sensitivity analysis showed that the value of lambda depended mainly on the juvenile survival rate. The impairment of this latter parameter may result in extinction of V. piscinalis. Finally, the present study highlights advantages of the proposed modeling approach in V. piscinalis and possible transfer to other test species and contaminants.

The interplay between cooperativity and diversity in model threshold ensembles

PubMed Central

Cervera, Javier; Manzanares, José A.; Mafe, Salvador

2014-01-01

The interplay between cooperativity and diversity is crucial for biological ensembles because single molecule experiments show a significant degree of heterogeneity and also for artificial nanostructures because of the high individual variability characteristic of nanoscale units. We study the cross-effects between cooperativity and diversity in model threshold ensembles composed of individually different units that show a cooperative behaviour. The units are modelled as statistical distributions of parameters (the individual threshold potentials here) characterized by central and width distribution values. The simulations show that the interplay between cooperativity and diversity results in ensemble-averaged responses of interest for the understanding of electrical transduction in cell membranes, the experimental characterization of heterogeneous groups of biomolecules and the development of biologically inspired engineering designs with individually different building blocks. PMID:25142516

Effect of ferroelectric BaTiO3 particles on the threshold voltage of a smectic A liquid crystal

PubMed Central

Imamaliyev, Abbas Rahim; Ramazanov, Mahammadali Ahmad

2018-01-01

The influence of small ferroelectric BaTiO3 particles on the planar–homeotropic transition threshold voltage in smectic A liquid crystals consisting of p-nitrophenyl p-decyloxybenzoate and 4-cyano-4′-pentylbiphenyl were studied by using capacitance–voltage (C–V) measurements. It was shown that the BaTiO3 particles significantly reduce the threshold voltage. The obtained result is explained by two factors: an increase of dielectric anisotropy of the liquid crystals and the formation of a strong electric field near polarized particles of BaTiO3. It was shown that the role of the second factor is dominant. The explanations of some features observed in the C–V characteristics are given. PMID:29600143

Hypergravity modulates behavioral nociceptive responses in rats

NASA Astrophysics Data System (ADS)

Kumei, Y.; Shimokawa, R.; Toda, K.; Kawauchi, Y.; Makita, K.; Terasawa, M.; Ohya, K.; Shimokawa, H.

Hypergravity (2G) exposure elevated the nociceptive threshold (pain suppression) concomitantly with evoked neuronal activity in the hypothalamus. Young Wistar male rats were exposed to 2G by centrifugal rotation for 10 min. Before and after 2G exposure, the nociceptive threshold was measured as the withdrawal reflex by using the von Frey type needle at a total of 8 sites of each rat (nose, four quarters, upper and lower back, tail), and then rats were sacrificed. Fos expression was examined immunohistochemically in the hypothalamic slices of the 2G-treated rats. When rats were exposed to 2G hypergravity, the nociceptive threshold was significantly elevated to approximately 150 to 250% of the 1G baseline control levels in all the examination sites. The 2G hypergravity remarkably induced Fos expression in the paraventricular and arcuate nuclei of the hypothalamus. The analgesic effects of 2G hypergravity were attenuated by naloxone pretreatment. Data indicate that hypergravity induces analgesic effects in rats, mediated through hypothalamic neuronal activity in the endogenous opioid system and hypothalamo-pituitary-adrenal axis.

Contagion on complex networks with persuasion

NASA Astrophysics Data System (ADS)

Huang, Wei-Min; Zhang, Li-Jie; Xu, Xin-Jian; Fu, Xinchu

2016-03-01

The threshold model has been widely adopted as a classic model for studying contagion processes on social networks. We consider asymmetric individual interactions in social networks and introduce a persuasion mechanism into the threshold model. Specifically, we study a combination of adoption and persuasion in cascading processes on complex networks. It is found that with the introduction of the persuasion mechanism, the system may become more vulnerable to global cascades, and the effects of persuasion tend to be more significant in heterogeneous networks than those in homogeneous networks: a comparison between heterogeneous and homogeneous networks shows that under weak persuasion, heterogeneous networks tend to be more robust against random shocks than homogeneous networks; whereas under strong persuasion, homogeneous networks are more stable. Finally, we study the effects of adoption and persuasion threshold heterogeneity on systemic stability. Though both heterogeneities give rise to global cascades, the adoption heterogeneity has an overwhelmingly stronger impact than the persuasion heterogeneity when the network connectivity is sufficiently dense.

Contagion on complex networks with persuasion

PubMed Central

Huang, Wei-Min; Zhang, Li-Jie; Xu, Xin-Jian; Fu, Xinchu

2016-01-01

The threshold model has been widely adopted as a classic model for studying contagion processes on social networks. We consider asymmetric individual interactions in social networks and introduce a persuasion mechanism into the threshold model. Specifically, we study a combination of adoption and persuasion in cascading processes on complex networks. It is found that with the introduction of the persuasion mechanism, the system may become more vulnerable to global cascades, and the effects of persuasion tend to be more significant in heterogeneous networks than those in homogeneous networks: a comparison between heterogeneous and homogeneous networks shows that under weak persuasion, heterogeneous networks tend to be more robust against random shocks than homogeneous networks; whereas under strong persuasion, homogeneous networks are more stable. Finally, we study the effects of adoption and persuasion threshold heterogeneity on systemic stability. Though both heterogeneities give rise to global cascades, the adoption heterogeneity has an overwhelmingly stronger impact than the persuasion heterogeneity when the network connectivity is sufficiently dense. PMID:27029498

Contagion on complex networks with persuasion.

PubMed

Huang, Wei-Min; Zhang, Li-Jie; Xu, Xin-Jian; Fu, Xinchu

2016-03-31

The threshold model has been widely adopted as a classic model for studying contagion processes on social networks. We consider asymmetric individual interactions in social networks and introduce a persuasion mechanism into the threshold model. Specifically, we study a combination of adoption and persuasion in cascading processes on complex networks. It is found that with the introduction of the persuasion mechanism, the system may become more vulnerable to global cascades, and the effects of persuasion tend to be more significant in heterogeneous networks than those in homogeneous networks: a comparison between heterogeneous and homogeneous networks shows that under weak persuasion, heterogeneous networks tend to be more robust against random shocks than homogeneous networks; whereas under strong persuasion, homogeneous networks are more stable. Finally, we study the effects of adoption and persuasion threshold heterogeneity on systemic stability. Though both heterogeneities give rise to global cascades, the adoption heterogeneity has an overwhelmingly stronger impact than the persuasion heterogeneity when the network connectivity is sufficiently dense.

The influence of prior exercise at anaerobic threshold on decompression sickness

NASA Technical Reports Server (NTRS)

Kumar, K. V.; Waligora, James M.; Gilbert, John H., III

1992-01-01

This study was conducted to examine the effects of exercise prior to decompression on the incidence of altitude decompression sickness (DCS). In a balanced, two-period, crossover trial, 39 healthy individuals were each exposed twice, without denitrogenation, to an altitude of 6400 m in a hypobaric chamber. Under the experimental condition, subjects exercised at their predetermined anaerobic threshold levels for 30 min each day for 3 d prior to altitude exposure; the other condition was a non-exercise control. Under both conditions, subjects performed exercise simulating space extravehicular activities at altitude for a period of 3 h, while breathing 100 percent oxygen. There were nine preferences (untied responses) for DCS, four under control and five under experimental conditions; all were Type I, pain-only bends. No carry-over effects between exposures was detected, and the test for treatment differences showed p = 0.56 for symptoms. No significant difference in DCS preferences was found after subjects exercised up to their anaerobic threshold levels during the days prior to decompression.

Penetration of resonant magnetic perturbations in a rotating tokamak plasma with neoclassical poloidal viscosity

NASA Astrophysics Data System (ADS)

Wang, Jialei; Wang, Zheng-Xiong; Wei, Lai

2015-09-01

The penetration of time-dependant resonant magnetic perturbations (RMPs) is numerically studied by means of reduced magnetohydrodynamic simulations, taking into account the neoclassical poloidal viscosity (NPV) damping. It is found that with the increase of the RMP growth rate, the scalings of penetration threshold on resistivity as well as viscosity are significantly weakened in both viscoresistive and resistive-inertial regimes. In the high neoclassical viscosity regime, the scalings on neoclassical viscosity ν n c are numerically obtained in the cases of different RMP growth rate and viscosity ν. In the low neoclassical viscosity regime, ν n c almost has no effect on penetration threshold, which is unlike ν. Moreover, the synergistic effect of both ν n c and ν on the threshold is discussed as well. Finally, the role of the NPV in the torque balance is analysed. It is shown that the NPV tends to restore the velocity profile in the vicinity of the rational surface.

Determinants of Change in the Cost-effectiveness Threshold.

PubMed

Paulden, Mike; O'Mahony, James; McCabe, Christopher

2017-02-01

The cost-effectiveness threshold in health care systems with a constrained budget should be determined by the cost-effectiveness of displacing health care services to fund new interventions. Using comparative statics, we review some potential determinants of the threshold, including the budget for health care, the demand for existing health care interventions, the technical efficiency of existing interventions, and the development of new health technologies. We consider the anticipated direction of impact that would affect the threshold following a change in each of these determinants. Where the health care system is technically efficient, an increase in the health care budget unambiguously raises the threshold, whereas an increase in the demand for existing, non-marginal health interventions unambiguously lowers the threshold. Improvements in the technical efficiency of existing interventions may raise or lower the threshold, depending on the cause of the improvement in efficiency, whether the intervention is already funded, and, if so, whether it is marginal. New technologies may also raise or lower the threshold, depending on whether the new technology is a substitute for an existing technology and, again, whether the existing technology is marginal. Our analysis permits health economists and decision makers to assess if and in what direction the threshold may change over time. This matters, as threshold changes impact the cost-effectiveness of interventions that require decisions now but have costs and effects that fall in future periods.

The effect of head protection on the hearing of rugby players.

PubMed

Kieran, S M; Dunne, J; Hughes, J P; Fenton, J E

2008-09-01

Professional rugby players utilise various methods of head protection to prevent against the development of a pinna haematoma. This study tests the hypothesis that these measures, whilst preventing injury, decrease the wearers' hearing threshold and therefore their performance. Eight patients had free field audiometry performed in a soundproof room, with warble tones. All patients were young men (mean 24.75 years (range 22-34)). No participant had ear symptomatology or a past history of ear surgery. Three separate audiological assessments were performed on each patient: normal free field audiometry in a sound field room, following application of adhesive tape and whilst wearing a scrum cap. All measurements were performed by a single audiological scientist. A significant clinical drop in hearing threshold was defined as an increase of 10 dB. No patient demonstrated a significant drop in hearing threshold following the application of either tape or a scrum cap, nor was there a significant difference in the mean (SD) warble tone average: air 7.03 (5.47); tape 7.19 (6.40); scrum cap 6.56 (5.58). Theoretical concerns that "ear taping" and scrum caps affect hearing of rugby players are unfounded and should not discourage their use.

Closed-loop adaptation of neurofeedback based on mental effort facilitates reinforcement learning of brain self-regulation.

PubMed

Bauer, Robert; Fels, Meike; Royter, Vladislav; Raco, Valerio; Gharabaghi, Alireza

2016-09-01

Considering self-rated mental effort during neurofeedback may improve training of brain self-regulation. Twenty-one healthy, right-handed subjects performed kinesthetic motor imagery of opening their left hand, while threshold-based classification of beta-band desynchronization resulted in proprioceptive robotic feedback. The experiment consisted of two blocks in a cross-over design. The participants rated their perceived mental effort nine times per block. In the adaptive block, the threshold was adjusted on the basis of these ratings whereas adjustments were carried out at random in the other block. Electroencephalography was used to examine the cortical activation patterns during the training sessions. The perceived mental effort was correlated with the difficulty threshold of neurofeedback training. Adaptive threshold-setting reduced mental effort and increased the classification accuracy and positive predictive value. This was paralleled by an inter-hemispheric cortical activation pattern in low frequency bands connecting the right frontal and left parietal areas. Optimal balance of mental effort was achieved at thresholds significantly higher than maximum classification accuracy. Rating of mental effort is a feasible approach for effective threshold-adaptation during neurofeedback training. Closed-loop adaptation of the neurofeedback difficulty level facilitates reinforcement learning of brain self-regulation. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Assessment of the Anticonvulsant Potency of Ursolic Acid in Seizure Threshold Tests in Mice.

PubMed

Nieoczym, Dorota; Socała, Katarzyna; Wlaź, Piotr

2018-05-01

Ursolic acid (UA) is a plant derived compound which is also a component of the standard human diet. It possesses a wide range of pharmacological properties, i.e., antioxidant, anti-inflammatory, antimicrobial and antitumor, which have been used in folk medicine for centuries. Moreover, influence of UA on central nervous system-related processes, i.e., pain, anxiety and depression, was proved in experimental studies. UA also revealed anticonvulsant properties in animal models of epilepsy and seizures. The aim of the present study was to investigate the influence of UA on seizure thresholds in three acute seizure models in mice, i.e., the 6 Hz-induced psychomotor seizure threshold test, the maximal electroshock threshold (MEST) test and the timed intravenous pentylenetetrazole (iv PTZ) infusion test. We also examined its effect on the muscular strength (assessed in the grip strength test) and motor coordination (estimated in the chimney test) in mice. UA at doses of 50 and 100 mg/kg significantly increased the seizure thresholds in the 6 Hz and MEST tests. The studied compound did not influence the seizure thresholds in the iv PTZ test. Moreover, UA did not affect the motor coordination and muscular strength in mice. UA displays only a weak anticonvulsant potential which is dependent on the used seizure model.

Variation of surface ozone in Campo Grande, Brazil: meteorological effect analysis and prediction.

PubMed

Pires, J C M; Souza, A; Pavão, H G; Martins, F G

2014-09-01

The effect of meteorological variables on surface ozone (O3) concentrations was analysed based on temporal variation of linear correlation and artificial neural network (ANN) models defined by genetic algorithms (GAs). ANN models were also used to predict the daily average concentration of this air pollutant in Campo Grande, Brazil. Three methodologies were applied using GAs, two of them considering threshold models. In these models, the variables selected to define different regimes were daily average O3 concentration, relative humidity and solar radiation. The threshold model that considers two O3 regimes was the one that correctly describes the effect of important meteorological variables in O3 behaviour, presenting also a good predictive performance. Solar radiation, relative humidity and rainfall were considered significant for both O3 regimes; however, wind speed (dispersion effect) was only significant for high concentrations. According to this model, high O3 concentrations corresponded to high solar radiation, low relative humidity and wind speed. This model showed to be a powerful tool to interpret the O3 behaviour, being useful to define policy strategies for human health protection regarding air pollution.

Emotions in freely varying and mono-pitched vowels, acoustic and EGG analyses.

PubMed

Waaramaa, Teija; Palo, Pertti; Kankare, Elina

2015-12-01

Vocal emotions are expressed either by speech or singing. The difference is that in singing the pitch is predetermined while in speech it may vary freely. It was of interest to study whether there were voice quality differences between freely varying and mono-pitched vowels expressed by professional actors. Given their profession, actors have to be able to express emotions both by speech and singing. Electroglottogram and acoustic analyses of emotional utterances embedded in expressions of freely varying vowels [a:], [i:], [u:] (96 samples) and mono-pitched protracted vowels (96 samples) were studied. Contact quotient (CQEGG) was calculated using 35%, 55%, and 80% threshold levels. Three different threshold levels were used in order to evaluate their effects on emotions. Genders were studied separately. The results suggested significant gender differences for CQEGG 80% threshold level. SPL, CQEGG, and F4 were used to convey emotions, but to a lesser degree, when F0 was predetermined. Moreover, females showed fewer significant variations than males. Both genders used more hypofunctional phonation type in mono-pitched utterances than in the expressions with freely varying pitch. The present material warrants further study of the interplay between CQEGG threshold levels and formant frequencies, and listening tests to investigate the perceptual value of the mono-pitched vowels in the communication of emotions.

Genetic architecture of threshold reaction norms for male alternative reproductive tactics in Atlantic salmon (Salmo salar L.)

PubMed Central

Lepais, Olivier; Manicki, Aurélie; Glise, Stéphane; Buoro, Mathieu; Bardonnet, Agnès

2017-01-01

Alternative mating tactics have important ecological and evolutionary implications and are determined by complex interactions between environmental and genetic factors. Here, we study the genetic effect and architecture of the variability in reproductive tactics among Atlantic salmon males which can either mature sexually early in life in freshwater or more commonly only after completing a migration at sea. We applied the latent environmental threshold model (LETM), which provides a conceptual framework linking individual status to a threshold controlling the decision to develop alternative traits, in an innovative experimental design using a semi-natural river which allowed for ecologically relevant phenotypic expression. Early male parr maturation rates varied greatly across families (10 to 93%) which translated into 90% [64–100%] of the phenotypic variation explained by genetic variation. Three significant QTLs were found for the maturation status, however only one collocated with a highly significant QTL explaining 20.6% of the variability of the maturation threshold located on chromosome 25 and encompassing a locus previously shown to be linked to sea age at maturity in anadromous Atlantic salmon. These results provide new empirical illustration of the relevance of the LETM for a better understanding of alternative mating tactics evolution in natural populations. PMID:28281522

Should high-power posing be integrated in physical therapy?

PubMed

Ge, Weiqing; Bennett, Teale K; Oller, Jeremy C

2017-04-01

[Purpose] Postural assessment and correction is a common approach in patient management to decrease symptoms and improve function for patients. The purpose of this study was to determine the effects of high-power posing on muscle strength and pain threshold. [Subjects and Methods] Thirty-one subjects, 16 females and 15 males, mean age 28.9 (SD 10.8) years old, were recruited through a convenience sampling on the university campus. The research design was a randomized controlled trial. In the experimental group, the subjects were instructed to stand in a high-power posture. In the control group, the subjects were instructed to stand in a low-power posture. Grip strength and pain threshold measurements were conducted before and after the postural intervention. [Results] The grip strength changed by -3.4 (-3.7, 0.3) % and 1.7 (-3.6, 5.3) % for the experimental and control groups, respectively. The pain threshold changed by 0.6 (-9.9, 10.4) % and 15.1 (-9.3, 24.4) % for the experimental and control groups, respectively. However, both changes were not significant as all the 95% CIs included 0. [Conclusions] The data did not show significant benefits of high-power posing in increasing grip strength and pain threshold compared to low-power posing.

Should high-power posing be integrated in physical therapy?

PubMed Central

Ge, Weiqing; Bennett, Teale K.; Oller, Jeremy C.

2017-01-01

[Purpose] Postural assessment and correction is a common approach in patient management to decrease symptoms and improve function for patients. The purpose of this study was to determine the effects of high-power posing on muscle strength and pain threshold. [Subjects and Methods] Thirty-one subjects, 16 females and 15 males, mean age 28.9 (SD 10.8) years old, were recruited through a convenience sampling on the university campus. The research design was a randomized controlled trial. In the experimental group, the subjects were instructed to stand in a high-power posture. In the control group, the subjects were instructed to stand in a low-power posture. Grip strength and pain threshold measurements were conducted before and after the postural intervention. [Results] The grip strength changed by −3.4 (−3.7, 0.3) % and 1.7 (−3.6, 5.3) % for the experimental and control groups, respectively. The pain threshold changed by 0.6 (−9.9, 10.4) % and 15.1 (−9.3, 24.4) % for the experimental and control groups, respectively. However, both changes were not significant as all the 95% CIs included 0. [Conclusions] The data did not show significant benefits of high-power posing in increasing grip strength and pain threshold compared to low-power posing. PMID:28533612

A newly identified calculation discrepancy of the Sunset semi-continuous carbon analyzer

NASA Astrophysics Data System (ADS)

Zheng, G.; Cheng, Y.; He, K.; Duan, F.; Ma, Y.

2014-01-01

Sunset Semi-Continuous Carbon Analyzer (SCCA) is an instrument widely used for carbonaceous aerosol measurement. Despite previous validation work, here we identified a new type of SCCA calculation discrepancy caused by the default multi-point baseline correction method. When exceeding a certain threshold carbon load, multi-point correction could cause significant Total Carbon (TC) underestimation. This calculation discrepancy was characterized for both sucrose and ambient samples with three temperature protocols. For ambient samples, 22%, 36% and 12% TC was underestimated by the three protocols, respectively, with corresponding threshold being ~0, 20 and 25 μg C. For sucrose, however, such discrepancy was observed with only one of these protocols, indicating the need of more refractory SCCA calibration substance. The discrepancy was less significant for the NIOSH (National Institute for Occupational Safety and Health)-like protocol compared with the other two protocols based on IMPROVE (Interagency Monitoring of PROtected Visual Environments). Although the calculation discrepancy could be largely reduced by the single-point baseline correction method, the instrumental blanks of single-point method were higher. Proposed correction method was to use multi-point corrected data when below the determined threshold, while use single-point results when beyond that threshold. The effectiveness of this correction method was supported by correlation with optical data.

[Effect of the middle ear status on the recording of vestibular evoked myogenic potential--VEMP].

PubMed

Kurzyna, Agnieszka; Hassmann-Poznańska, Elzbieta; Topolska, Małgorzata Maria

2005-01-01

The aim of this study was to assess the effect of the middle ear status on the recording of air- and bone-conducted vestibular evoked myogenic potential. Forty eight children were included in the study, ranging in age from 4 to 10 years. All of the children underwent otoscopy, pure tone audiometry, tympanometry and air- and bone-conducted VEMP in response to click. There were 3 groups according to the condition of the middle ear: group I--52 ears (type A and C1 tympanogram, pure tone average < or = 20 dB), group II--23 ears (type C2 and B tympanogram, pure tone average < or = 20 dB), group III--21 (type B tympanogram, pure tone average > 20 dB). The threshold, presence of correct waveform morphology of the response and latency was evaluated. The condition of the middle ear has no significant effect on the recording of VEMP and mean level of the response threshold with bone stimulation, based on the performed studies. However, with air stimulation it has effect on the recording of VEMP, increase of the mean threshold response and shortening of latency p13 and n23.

[Using fractional polynomials to estimate the safety threshold of fluoride in drinking water].

PubMed

Pan, Shenling; An, Wei; Li, Hongyan; Yang, Min

2014-01-01

To study the dose-response relationship between fluoride content in drinking water and prevalence of dental fluorosis on the national scale, then to determine the safety threshold of fluoride in drinking water. Meta-regression analysis was applied to the 2001-2002 national endemic fluorosis survey data of key wards. First, fractional polynomial (FP) was adopted to establish fixed effect model, determining the best FP structure, after that restricted maximum likelihood (REML) was adopted to estimate between-study variance, then the best random effect model was established. The best FP structure was first-order logarithmic transformation. Based on the best random effect model, the benchmark dose (BMD) of fluoride in drinking water and its lower limit (BMDL) was calculated as 0.98 mg/L and 0.78 mg/L. Fluoride in drinking water can only explain 35.8% of the variability of the prevalence, among other influencing factors, ward type was a significant factor, while temperature condition and altitude were not. Fractional polynomial-based meta-regression method is simple, practical and can provide good fitting effect, based on it, the safety threshold of fluoride in drinking water of our country is determined as 0.8 mg/L.

Tax incentives and the demand for private health insurance.

PubMed

Stavrunova, Olena; Yerokhin, Oleg

2014-03-01

We analyze the effect of an individual insurance mandate (Medicare Levy Surcharge) on the demand for private health insurance (PHI) in Australia. With administrative income tax return data, we show that the mandate has several distinct effects on taxpayers' behavior. First, despite the large tax penalty for not having PHI coverage relative to the cost of the cheapest eligible insurance policy, compliance with mandate is relatively low: the proportion of the population with PHI coverage increases by 6.5 percentage points (15.6%) at the income threshold where the tax penalty starts to apply. This effect is most pronounced for young taxpayers, while the middle aged seem to be least responsive to this specific tax incentive. Second, the discontinuous increase in the average tax rate at the income threshold created by the policy generates a strong incentive for tax avoidance which manifests itself through bunching in the taxable income distribution below the threshold. Finally, after imposing some plausible assumptions, we extrapolate the effect of the policy to other income levels and show that this policy has not had a significant impact on the overall demand for private health insurance in Australia. Copyright © 2014 Elsevier B.V. All rights reserved.

Pseudo-low Frequency Hearing Loss and Its Improvement After Treatment May Be Objective Signs of Significant Vascular Pathology in Patients With Pulsatile Tinnitus.

PubMed

Jeon, Hyoung Won; Kim, So Young; Choi, Byung Se; Bae, Yun Jung; Koo, Ja-Won; Song, Jae-Jin

2016-10-01

In patients with pulsatile tinnitus (PT), physical examination such as auscultation with head position change or digital compression over the ipsilateral jugular vein provides physicians with important information. However, objective diagnosis of PT is sometimes limited because 1) audible bruit is absent on auscultation in some patients, 2) abnormal vascular structures found in radiologic evaluation is not always pathognomonic because they can be found in asymptomatic subjects as well, and 3) although an objective diagnostic tool using transcanal sound recording has recently been introduced, special equipment is needed. In this regard, recent studies that have reported ipsilateral low-frequency hearing loss (LFHL) on pure-tone audiometry (PTA) in some patients with PT, and its recovery after successful management, prompted us to conduct a retrospective observational study on the characteristics of the audiometric profile, the association between the audiometric profile and radiologic findings, and pre- and posttreatment changes in low-frequency hearing thresholds in PT patients. We tested two hypotheses: PT patients with marked vascular pathologies located close to the cochlea may show ipsilateral pseudo-LFHL (PLFHL) because of the masking effects of the PT itself, and their PLFHL may disappear if their vascular pathology is successfully managed by surgical or endovascular intervention. Retrospective case review. Tertiary referral center. A total of 85 PT subjects who underwent both audiologic and radiologic examinations. All patients' pre- and posttreatment PTA thresholds and radiologic findings were analyzed. By comparing the LFHL (an ipsilateral hearing threshold greater than 10 dB HL at both 250 and 500 Hz or greater than 20 dB HL at either 250 or 500 Hz compared with the contralateral side) group and a non-LFHL group with regard to the incidence of vascular structural abnormalities, we evaluated the incidence of abnormal vascular structures in the head and neck between the LFHL and non-LFHL groups. In addition, by comparing pre- and posttreatment PTA thresholds of seven PT patients with ipsilateral LFHL, we further evaluated the changes in low-frequency hearing thresholds and their role as an objective sign for diagnosis and outcome evaluation. Of 85 patients, 22 (25.9%) presented with ipsilateral LFHL. Compared with patients without this condition, patients with ipsilateral LFHL showed a significantly higher rate of abnormal vascular structure. In addition, most of the radiologic abnormalities found in the LFHL group were highly suspicious causative lesions that are responsible for the perception of PT according to the previous literature. In eight PT patients with ipsilateral LFHL who underwent both pre- and posttreatment audiograms, the average posttreatment pure-tone threshold at 250 Hz showed significant improvement compared with the pretreatment threshold. PT patients presenting with ipsilateral LFHL have higher possibility of having a discrete vascular pathology near the cochlea on radiologic evaluation. As ipsilateral LFHL improves in most patients after treatment, LFHL in patients with PT may be PLFHL because of the masking effects of the pulsatile sound, and the changes in the low-frequency thresholds may be applicable for objective diagnosis and evaluation of the effects of the treatment.

Observation of a cross-section enhancement near mass threshold in e + e - → Λ Λ ¯

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ablikim, M.; Achasov, M. N.; Ahmed, S.

Tmore » he process e + e - → Λ Λ ¯ is studied using data samples at √s = 2.2324, 2.400, 2.800 and 3.080 GeV collected with the BESIII detector operating at the BEPCII collider. he Born cross section is measured at √s=2.2324 GeV, which is 1.0 MeV above the Λ Λ ¯ mass threshold, to be 305±$$45_{-36}^{+66}$$ pb, where the first uncertainty is statistical and the second systematic. he substantial cross section near threshold is significantly larger than that expected from theory, which predicts the cross section to vanish at threshold. he Born cross sections at √s=2.400, 2.800 and 3.080 GeV are measured and found to be consistent with previous experimental results, but with improved precision. Finally, the corresponding effective electromagnetic form factors of Λ are deduced.« less

Observation of a cross-section enhancement near mass threshold in e + e - → Λ Λ ¯

DOE PAGES

Ablikim, M.; Achasov, M. N.; Ahmed, S.; ...

2018-02-28

Tmore » he process e + e - → Λ Λ ¯ is studied using data samples at √s = 2.2324, 2.400, 2.800 and 3.080 GeV collected with the BESIII detector operating at the BEPCII collider. he Born cross section is measured at √s=2.2324 GeV, which is 1.0 MeV above the Λ Λ ¯ mass threshold, to be 305±$$45_{-36}^{+66}$$ pb, where the first uncertainty is statistical and the second systematic. he substantial cross section near threshold is significantly larger than that expected from theory, which predicts the cross section to vanish at threshold. he Born cross sections at √s=2.400, 2.800 and 3.080 GeV are measured and found to be consistent with previous experimental results, but with improved precision. Finally, the corresponding effective electromagnetic form factors of Λ are deduced.« less

Effect of interface-dependent crystalline boundary on sub-threshold characteristics in a solution-processed 6,13-bis(triisopropylsilylethynyl)-pentacene thin-film transistor

NASA Astrophysics Data System (ADS)

Kwon, Jin-Hyuk; Kang, In Man; Bae, Jin-Hyuk

2014-03-01

We demonstrate how the sub-threshold characteristics are affected by the density of crystalline domain boundaries directly governed by an organic semiconductor (OSC) - a gate insulator interface in a solution-processed 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) thin-film transistor (TFT). For generation of an engineered interface, a self assembled monolayer of octadecyltricholorosilane (OTS) was produced between a solution processed TIPS-pentacene film and a silicon dioxide layer. The interfacial charge trap density (Ntrap) deduced from the sub-threshold characteristics was significantly minimized after OTS treatment due to reduced crystal domain boundaries in the TIPS-pentacene film. In addition, the carrier mobility exhibits a value twice as large by OTS treatment. It is found that less crystal domain boundaries in the solution-processed OSC obtained from the engineered interface play an important role in inducing improved sub-threshold characteristics together with increased carrier mobility in organic TFTs.

Comparison of pressure pain threshold, grip strength,dexterity and touch pressure of dominant and non-dominant hands within and between right-and left-handed subjects.

PubMed

Ozcan, Ayse; Tulum, Zeliha; Pinar, Lamia; Başkurt, Ferdi

2004-12-01

This study was done to evaluate differences in pressure pain threshold, grip strength, manual dexterity and touch pressure threshold in the dominant and non-dominant hands of right- and left-handed subjects, and to compare findings within and between these groups. Thirty-nine right-handed and twenty-one left-handed subjects participated in the study. Pressure pain threshold was assessed using a dolorimeter, grip strength was assessed with a hand-grip dynamometer, manual dexterity was evaluated using the VALPAR Component Work Sample-4 system, and touch pressure threshold was determined using Semmes Weinstein monofilaments. Results for the dominant and non-dominant hands were compared within and between the groups. In the right-handed subjects, the dominant hand was significantly faster with the VALPAR Component Work Sample-4, showed significantly greater grip strength, and had a significantly higher pressure pain threshold than the non-dominant hand. The corresponding results for the two hands were similar in the left-handed subjects. The study revealed asymmetrical manual performance in grip strength, manual dexterity and pressure pain threshold in right-handed subjects, but no such asymmetries in left-handed subjects.

Analyzing threshold pressure limitations in microfluidic transistors for self-regulated microfluidic circuits

PubMed Central

Kim, Sung-Jin; Yokokawa, Ryuji; Takayama, Shuichi

2012-01-01

This paper reveals a critical limitation in the electro-hydraulic analogy between a microfluidic membrane-valve (μMV) and an electronic transistor. Unlike typical transistors that have similar on and off threshold voltages, in hydraulic μMVs, the threshold pressures for opening and closing are significantly different and can change, even for the same μMVs depending on overall circuit design and operation conditions. We explain, in particular, how the negative values of the closing threshold pressures significantly constrain operation of even simple hydraulic μMV circuits such as autonomously switching two-valve microfluidic oscillators. These understandings have significant implications in designing self-regulated microfluidic devices. PMID:23284181

Calculating the dim light melatonin onset: the impact of threshold and sampling rate.

PubMed

Molina, Thomas A; Burgess, Helen J

2011-10-01

The dim light melatonin onset (DLMO) is the most reliable circadian phase marker in humans, but the cost of assaying samples is relatively high. Therefore, the authors examined differences between DLMOs calculated from hourly versus half-hourly sampling and differences between DLMOs calculated with two recommended thresholds (a fixed threshold of 3 pg/mL and a variable "3k" threshold equal to the mean plus two standard deviations of the first three low daytime points). The authors calculated these DLMOs from salivary dim light melatonin profiles collected from 122 individuals (64 women) at baseline. DLMOs derived from hourly sampling occurred on average only 6-8 min earlier than the DLMOs derived from half-hourly saliva sampling, and they were highly correlated with each other (r ≥ 0.89, p < .001). However, in up to 19% of cases the DLMO derived from hourly sampling was >30 min from the DLMO derived from half-hourly sampling. The 3 pg/mL threshold produced significantly less variable DLMOs than the 3k threshold. However, the 3k threshold was significantly lower than the 3 pg/mL threshold (p < .001). The DLMOs calculated with the 3k method were significantly earlier (by 22-24 min) than the DLMOs calculated with the 3 pg/mL threshold, regardless of sampling rate. These results suggest that in large research studies and clinical settings, the more affordable and practical option of hourly sampling is adequate for a reasonable estimate of circadian phase. Although the 3 pg/mL fixed threshold is less variable than the 3k threshold, it produces estimates of the DLMO that are further from the initial rise of melatonin.

Preservation of auditory brainstem response thresholds after cochleostomy and titanium microactuator implantation in the lateral wall of cat scala tympani.

PubMed

Lesinski, S George; Prewitt, Jessica; Bray, Victor; Aravamudhan, Radhika; Bermeo Blanco, Oscar A; Farmer-Fedor, Brenda L; Ward, Jonette A

2014-04-01

The safety of implanting a titanium microactuator into the lateral wall of cat scala tympani was assessed by comparing preoperative and postoperative auditory brainstem response (ABR) thresholds for 1 to 3 months. The safety of directly stimulating cochlear perilymph with an implantable hearing system requires maintaining preoperative hearing levels. This cat study is an essential step in the development of the next generation of fully implantable hearing devices for humans. Following GLP surgical standards, a 1-mm cochleostomy was drilled into the lateral wall of the scala tympani, and a nonfunctioning titanium anchor/microactuator assembly was inserted in 8 cats. The scala media was damaged in the 1 cat. ABR thresholds with click and 4- and 8-kHz stimuli were measured preoperatively and compared with postoperative thresholds at 1, 2, and 3 months. Nonimplanted ear thresholds were also measured to establish statistical significance for threshold shifts (>28.4 dB). Two audiologists independently interpreted thresholds. Postoperatively, 7 cats implanted in the scala tympani demonstrated no significant ABR threshold shift for click stimulus; one shifted ABR thresholds to 4- and 8-kHz stimuli. The eighth cat, with surgical damage to the scala media, maintained stable click threshold but had a significant shift to 4- and 8-kHz stimuli. This cat study provides no evidence of worsening hearing thresholds after fenestration of the scala tympani and insertion of a titanium anchor/microactuator, provided there is no surgical trauma to the scala media and the implanted device is securely anchored in the cochleostomy. These 2 issues have been resolved in the development of a fully implantable hearing system for humans. The long-term hearing stability (combined with histologic studies) reaffirm that the microactuator is well tolerated by the cat cochlea.

Exercise increases pressure pain tolerance but not pressure and heat pain thresholds in healthy young men.

PubMed

Vaegter, H B; Hoeger Bement, M; Madsen, A B; Fridriksson, J; Dasa, M; Graven-Nielsen, T

2017-01-01

Exercise causes an acute decrease in the pain sensitivity known as exercise-induced hypoalgesia (EIH), but the specificity to certain pain modalities remains unknown. This study aimed to compare the effect of isometric exercise on the heat and pressure pain sensitivity. On three different days, 20 healthy young men performed two submaximal isometric knee extensions (30% maximal voluntary contraction in 3 min) and a control condition (quiet rest). Before and immediately after exercise and rest, the sensitivity to heat pain and pressure pain was assessed in randomized and counterbalanced order. Cuff pressure pain threshold (cPPT) and pain tolerance (cPTT) were assessed on the ipsilateral lower leg by computer-controlled cuff algometry. Heat pain threshold (HPT) was recorded on the ipsilateral foot by a computer-controlled thermal stimulator. Cuff pressure pain tolerance was significantly increased after exercise compared with baseline and rest (p < 0.05). Compared with rest, cPPT and HPT were not significantly increased by exercise. No significant correlation between exercise-induced changes in HPT and cPPT was found. Test-retest reliability before and after the rest condition was better for cPPT and CPTT (intraclass correlation > 0.77) compared with HPT (intraclass correlation = 0.54). The results indicate that hypoalgesia after submaximal isometric exercise is primarily affecting tolerance of pressure pain compared with the pain threshold. These data contribute to the understanding of how isometric exercise influences pain perception, which is necessary to optimize the clinical utility of exercise in management of chronic pain. The effect of isometric exercise on pain tolerance may be relevant for patients in chronic musculoskeletal pain as a pain-coping strategy. WHAT DOES THIS STUDY ADD?: The results indicate that hypoalgesia after submaximal isometric exercise is primarily affecting tolerance of pressure pain compared with the heat and pressure pain threshold. These data contribute to the understanding of how isometric exercise influences pain perception, which is necessary to optimize the clinical utility of exercise in management of chronic pain. © 2016 European Pain Federation - EFIC®.

Physical activity levels of normal-weight and overweight girls and boys during primary school recess.

PubMed

Stratton, Gareth; Ridgers, Nicola D; Fairclough, Stuart J; Richardson, David J

2007-06-01

This study aimed to compare moderate-to-vigorous physical activity (MVPA) and vigorous physical activity (VPA) in normal-weight and overweight boys and girls during school recess. Four hundred twenty children, age 6 to 10 years, were randomly selected from 25 schools in England. Three hundred seventy-seven children completed the study. BMI was calculated from height and weight measurements, and heart rate reserve thresholds of 50% and 75% reflected children's engagement in MVPA and VPA, respectively. There was a significant main effect for sex and a significant interaction between BMI category and sex for the percent of recess time spent in MVPA and VPA. Normal-weight girls were the least active group, compared with overweight boys and girls who were equally active. Fifty-one boys and 24 girls of normal weight achieved the 40% threshold; of these, 30 boys and 10 girls exceeded 50% of recess time in MVPA. Eighteen overweight boys and 22 overweight girls exceeded the 40% threshold, whereas 8 boys and 8 girls exceeded the 50% threshold. Overweight boys were significantly less active than their normal-weight male counterparts; this difference did not hold true for girls. Even though nearly double the number of normal-weight children achieved the 40% of MVPA during recess compared with overweight children, physical activity promotion in school playgrounds needs to be targeted not only at overweight but at other health parameters, as 40 overweight children met the 40% MVPA target proposed for recess.

Empirical estimation of genome-wide significance thresholds based on the 1000 Genomes Project data set.

PubMed

Kanai, Masahiro; Tanaka, Toshihiro; Okada, Yukinori

2016-10-01

To assess the statistical significance of associations between variants and traits, genome-wide association studies (GWAS) should employ an appropriate threshold that accounts for the massive burden of multiple testing in the study. Although most studies in the current literature commonly set a genome-wide significance threshold at the level of P=5.0 × 10 -8 , the adequacy of this value for respective populations has not been fully investigated. To empirically estimate thresholds for different ancestral populations, we conducted GWAS simulations using the 1000 Genomes Phase 3 data set for Africans (AFR), Europeans (EUR), Admixed Americans (AMR), East Asians (EAS) and South Asians (SAS). The estimated empirical genome-wide significance thresholds were P sig =3.24 × 10 -8 (AFR), 9.26 × 10 -8 (EUR), 1.83 × 10 -7 (AMR), 1.61 × 10 -7 (EAS) and 9.46 × 10 -8 (SAS). We additionally conducted trans-ethnic meta-analyses across all populations (ALL) and all populations except for AFR (ΔAFR), which yielded P sig =3.25 × 10 -8 (ALL) and 4.20 × 10 -8 (ΔAFR). Our results indicate that the current threshold (P=5.0 × 10 -8 ) is overly stringent for all ancestral populations except for Africans; however, we should employ a more stringent threshold when conducting a meta-analysis, regardless of the presence of African samples.

Effect of erythropoietin on acoustically traumatized rat cochlea: an immunohistochemical study.

PubMed

Gürgen, Oğuzhan; Gürgen, Seren Gülşen; Kirkim, Günay; Kolatan, Efsun; Gürkan, Selhan; Güvenç, Yeşim; Eskiizmir, Görkem

2014-08-01

To investigate the audiological and histopathological effects of erythropoietin on acoustic overstimulation in rats. Twenty-two male Wistar albino rats were divided into 3 groups: sham group (n = 7), erythropoietin injection group (n = 8), and saline injection group (n = 7). Both erythropoietin and saline injection groups were exposed to white noise (100 decibel [dB] sound pressure level [SPL]) for 3 hours. Auditory brainstem responses were measured before, immediately after, and on the 7th day of noise exposure. All animals were sacrificed on the 7th day and temporal bones were collected. The serial sections of the cochleae were stained by caspase-3 and caspase-9 immunostaining and by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method in order to detect apoptotic cells. In the saline group statistically significant differences were detected between the baseline and immediate postacoustic overstimulation thresholds of click and 6 kHz stimuli. However, when the baseline and immediate postacoustic overstimulation thresholds of click and 6 kHz stimuli were compared in the erythropoietin injection group, no statistically significant difference was determined. Histopathologic evaluations demonstrated that erythropoietin decreased the amount of apoptotic cells in the cochlea. Erythropoietin is likely to prevent the acute threshold changes and decrease the amount of apoptosis in cochlea after acoustic overstimulation in rats.

Functional impairment of the auditory pathway after perinatal asphyxia and the short-term effect of perinatal propofol anesthesia in lambs.

PubMed

Smit, Adriana L; Seehase, Matthias; Stokroos, Robert J; Jellema, Reint K; Felipe, Lilian; Chenault, Michelene N; Anteunis, Lucien J C; Kremer, Bernd; Kramer, Boris W

2013-07-01

Sensorineural hearing loss (SNHL) is a common feature in the postasphyxial syndrome in newborns. Several anesthetic drugs have been proposed to attenuate secondary neuronal injury elicited by hypoxia-ischemia. We hypothesized that propofol anesthesia reduces auditory impairment after perinatal asphyxia in comparison with isoflurane. Twenty-three pregnant ewes were randomized to propofol or isoflurane anesthesia and sedation. The lambs underwent in utero umbilical cord occlusion (isoflurane n = 5; propofol n = 7) and were compared with sham-treated animals (isoflurane n = 5; propofol n = 6) at a gestational age of 133 d. For 8 h after delivery by cesarean section, repeated auditory brainstem responses (ABRs) were recorded to obtain hearing thresholds, peak amplitudes, latencies, and interpeak latencies. Significantly elevated mean thresholds, diminished amplitudes, and elevated latencies were observed in the asphyxia group relative to the control group through the observation period. Comparison of anesthetic treatment in the asphyxia group revealed a significantly lower elevation in threshold and less impairment in the ABR amplitudes and latencies during propofol anesthesia as compared with isoflurane anesthesia. Our results support the hypothesis that anesthesia with propofol has a preventive effect on the functional changes to the auditory pathway in the event of perinatal asphyxia.

A wavelet-based adaptive fusion algorithm of infrared polarization imaging

NASA Astrophysics Data System (ADS)

Yang, Wei; Gu, Guohua; Chen, Qian; Zeng, Haifang

2011-08-01

The purpose of infrared polarization image is to highlight man-made target from a complex natural background. For the infrared polarization images can significantly distinguish target from background with different features, this paper presents a wavelet-based infrared polarization image fusion algorithm. The method is mainly for image processing of high-frequency signal portion, as for the low frequency signal, the original weighted average method has been applied. High-frequency part is processed as follows: first, the source image of the high frequency information has been extracted by way of wavelet transform, then signal strength of 3*3 window area has been calculated, making the regional signal intensity ration of source image as a matching measurement. Extraction method and decision mode of the details are determined by the decision making module. Image fusion effect is closely related to the setting threshold of decision making module. Compared to the commonly used experiment way, quadratic interpolation optimization algorithm is proposed in this paper to obtain threshold. Set the endpoints and midpoint of the threshold searching interval as initial interpolation nodes, and compute the minimum quadratic interpolation function. The best threshold can be obtained by comparing the minimum quadratic interpolation function. A series of image quality evaluation results show this method has got improvement in fusion effect; moreover, it is not only effective for some individual image, but also for a large number of images.

Using a higher criticism statistic to detect modest effects in a genome-wide study of rheumatoid arthritis

PubMed Central

2009-01-01

In high-dimensional studies such as genome-wide association studies, the correction for multiple testing in order to control total type I error results in decreased power to detect modest effects. We present a new analytical approach based on the higher criticism statistic that allows identification of the presence of modest effects. We apply our method to the genome-wide study of rheumatoid arthritis provided in the Genetic Analysis Workshop 16 Problem 1 data set. There is evidence for unknown bias in this study that could be explained by the presence of undetected modest effects. We compared the asymptotic and empirical thresholds for the higher criticism statistic. Using the asymptotic threshold we detected the presence of modest effects genome-wide. We also detected modest effects using 90th percentile of the empirical null distribution as a threshold; however, there is no such evidence when the 95th and 99th percentiles were used. While the higher criticism method suggests that there is some evidence for modest effects, interpreting individual single-nucleotide polymorphisms with significant higher criticism statistics is of undermined value. The goal of higher criticism is to alert the researcher that genetic effects remain to be discovered and to promote the use of more targeted and powerful studies to detect the remaining effects. PMID:20018032

Stress (hypothalamic-pituitary-adrenal axis) and pain response in male rats exposed lifelong to high vs. low phytoestrogen diets.

PubMed

Lephart, Edwin D; Galindo, Edwardo; Bu, Li Hong

2003-05-15

Estrogens exhibit complex but beneficial effects on brain structure, function and behavior. Soy-derived dietary phytoestrogens protect against hormone-dependent and age-related diseases, due to their estrogen-like hormonal actions. However, the effects of phytoestrogens on brain and behavior are relatively unknown. This study examined the influence of exposing male Long-Evans rats (lifelong) to either a phytoestrogen-rich (Phyto-600) or a phytoestrogen-free (Phyto-free) diet on body weights, behavioral pain thresholds, the hypothalamic-pituitary-adrenal (HPA) hormonal stress response, hippocampal glucocorticoid receptor and brain neural cell adhesion molecules (NCAM) and synaptophysin levels using standard behavioral and biochemical techniques. Body weights were significantly decreased in Phyto-600 fed animals compared to Phyto-free values. There were no significant changes in behavioral pain thresholds, circulating corticosterone concentrations (after acute immobilization stress) or NCAM and synaptophysin levels in various brain regions by the diet treatments. However, Phyto-600 fed males displayed significantly higher plasma adrenocorticotrophin (ACTH) (post-stress) and hippocampal glucocorticoid receptor levels vs. Phyto-free values. These data suggest that (1) body weights are significantly reduced by soy-derived phytoestrogens, (2) behavioral pain thresholds (via heat stimuli) are not influenced by dietary phytoestrogens, but (3) these estrogenic molecules in the hippocampus enhance glucocorticoid receptor abundance and alter the negative feedback of stress hormones towards a female-like pattern of higher ACTH release after activation of the HPA stress axis. This study is the first to show that lifelong consumption of dietary phytoestrogens alters the HPA stress response in male rats.

Effects of exercise continued until anaerobic threshold on balance performance in male basketball players.

PubMed

Erkmen, Nurtekin; Suveren, Sibel; Göktepe, Ahmet Salim

2012-06-01

The objective of the present study was to determine the effects of exercise continued until the anaerobic threshold on balance performance in basketball players. Twelve male basketball players (age = 20.92 ± 2.81 years, body height = 192.72 ± 7.61 cm, body mass = 88.09 ± 8.41 kg, training experience = 7.17 ± 3.10 years) volunteered to participate in this study. A Kinesthetic Ability Trainer (KAT 2000 stabilometer) was used to measure the balance performance. Balance tests consisted of static tests on dominant, nondominant and double leg stance. The Bruce Protocol was performed by means of a treadmill. The exercise protocol was terminated when the subject passed the anaerobic threshold. After the exercise protocol, balance measurements were immediately repeated. Statistical differences between pre and post-exercise for dominant, nondominant and double leg stance were determined by the paired samples t-test according to the results of the test of normality. The post-exercise balance score on the dominant leg was significantly higher than pre-exercise (t = -2.758, p < 0.05). No differences existed between pre- and post-exercise in the balance scores of the nondominant leg after the exercise protocol (t = 0.428, p > 0.05). A significant difference was found between pre and post-exercise balance scores in the double leg stance (t = -2.354, p < 0.05). The main finding of this study was that an incremental exercise continued until the anaerobic threshold decreased balance performance on the dominant leg in basketball players, but did not alter it in the nondominant leg.

Effects of intrathecal or intracerebroventricular administration of nonsteroidal anti-inflammatory drugs on a C-fiber reflex in rats.

PubMed

Bustamante, D; Paeile, C; Willer, J C; Le Bars, D

1997-06-01

A C-fiber reflex elicited by electrical stimulation within the territory of the sural nerve was recorded from the ipsilateral biceps femoris muscle in anesthetized rats. The temporal evolution of the response was studied using a constant stimulus intensity (3 times threshold), and recruitment curves were built by varying the stimulus intensity from 0 to 7 times threshold. The intrathecal (i.t.) but not i.c.v. administration of aspirin, indomethacin, ketoprofen and lysine clonixinate resulted in dose-dependent depressions of the C-fiber reflex. In contrast, saline was ineffective. Regardless of the route of administration, the drugs never produced disturbances in heart rate and/or acid-base equilibrium. When a constant level of stimulation was used, 500 microg of aspirin i.t. induced a blockade of the reflex immediately after the injection, followed by a partial recovery. Indomethacin produced a stable depression, which reached 80 to 90% with an i.t. dose of 500 microg. Ketoprofen and lysine clonixinate produced a more stable effect; the highest doses (500 microg) produced a steady-state depression of approximately 50% for approximately 30 min. When the recruitment curves were built with a range of nociceptive stimulus intensities, all of the drugs except for indomethacin produced a dose-dependent decrease in the slopes and the areas under the recruitment curves without major modifications in the thresholds; indomethacin also induced a significant dose-related increase in the threshold. The orders of potency for both stimulation paradigms with the i.t. route were the same, namely aspirin > indomethacin > lysine clonixinate > or = ketoprofen. It is concluded that nonsteroidal anti-inflammatory drugs elicit significant antinociceptive effects at a spinal level, which do not depend on the existence of a hyperalgesic or inflammatory state. Such effects were not seen after injections within the lateral ventricle.

Cost-effectiveness thresholds: methods for setting and examples from around the world.

PubMed

Santos, André Soares; Guerra-Junior, Augusto Afonso; Godman, Brian; Morton, Alec; Ruas, Cristina Mariano

2018-06-01

Cost-effectiveness thresholds (CETs) are used to judge if an intervention represents sufficient value for money to merit adoption in healthcare systems. The study was motivated by the Brazilian context of HTA, where meetings are being conducted to decide on the definition of a threshold. Areas covered: An electronic search was conducted on Medline (via PubMed), Lilacs (via BVS) and ScienceDirect followed by a complementary search of references of included studies, Google Scholar and conference abstracts. Cost-effectiveness thresholds are usually calculated through three different approaches: the willingness-to-pay, representative of welfare economics; the precedent method, based on the value of an already funded technology; and the opportunity cost method, which links the threshold to the volume of health displaced. An explicit threshold has never been formally adopted in most places. Some countries have defined thresholds, with some flexibility to consider other factors. An implicit threshold could be determined by research of funded cases. Expert commentary: CETs have had an important role as a 'bridging concept' between the world of academic research and the 'real world' of healthcare prioritization. The definition of a cost-effectiveness threshold is paramount for the construction of a transparent and efficient Health Technology Assessment system.

Vibrotactile Presentation of Musical Notes to the Glabrous Skin for Adults with Normal Hearing or a Hearing Impairment: Thresholds, Dynamic Range and High-Frequency Perception

PubMed Central

Maté-Cid, Saúl; Fulford, Robert; Seiffert, Gary; Ginsborg, Jane

2016-01-01

Presentation of music as vibration to the skin has the potential to facilitate interaction between musicians with hearing impairments and other musicians during group performance. Vibrotactile thresholds have been determined to assess the potential for vibrotactile presentation of music to the glabrous skin of the fingertip, forefoot and heel. No significant differences were found between the thresholds for sinusoids representing notes between C1 and C6 when presented to the fingertip of participants with normal hearing and with a severe or profound hearing loss. For participants with normal hearing, thresholds for notes between C1 and C6 showed the characteristic U-shape curve for the fingertip, but not for the forefoot and heel. Compared to the fingertip, the forefoot had lower thresholds between C1 and C3, and the heel had lower thresholds between C1 and G2; this is attributed to spatial summation from the Pacinian receptors over the larger contactor area used for the forefoot and heel. Participants with normal hearing assessed the perception of high-frequency vibration using 1s sinusoids presented to the fingertip and were found to be more aware of transient vibration at the beginning and/or end of notes between G4 and C6 when stimuli were presented 10dB above threshold, rather than at threshold. An average of 94% of these participants reported feeling continuous vibration between G4 and G5 with stimuli presented 10dB above threshold. Based on the experimental findings and consideration of health effects relating to vibration exposure, a suitable range of notes for vibrotactile presentation of music is identified as being from C1 to G5. This is more limited than for human hearing but the fundamental frequencies of the human voice, and the notes played by many instruments, lie within it. However, the dynamic range might require compression to avoid the negative effects of amplitude on pitch perception. PMID:27191400

Hydroxyisohexyl 3-cyclohexene carboxaldehyde allergy: relationship between patch test and repeated open application test thresholds.

PubMed

Fischer, L A; Menné, T; Avnstorp, C; Kasting, G B; Johansen, J D

2009-09-01

Hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) is a synthetic fragrance ingredient. Case reports of allergy to HICC appeared in the 1980s, and HICC has recently been included in the European baseline series. Human elicitation dose-response studies performed with different allergens have shown a significant relationship between the patch-test threshold and the repeated open application test (ROAT) threshold, which mimics some real-life exposure situations. Fragrance ingredients are special as significant amounts of allergen may evaporate from the skin. The study aimed to investigate the relationship between elicitation threshold doses at the patch test and the ROAT, using HICC as the allergen. The expected evaporation rate was calculated. Seventeen HICC-allergic persons were tested with a dilution series of HICC in a patch test and a ROAT (duration up to 21 days). Seventeen persons with no HICC allergy were included as control group for the ROAT. Results The response frequency to the ROAT (in microg HICC cm(-2) per application) was significantly higher than the response frequency to the patch test at one of the tested doses. Furthermore the response rate to the accumulated ROAT dose was significantly lower at half of the doses compared with the patch test. The evaporation rate of HICC was calculated to be 72% over a 24-h period. The ROAT threshold in dose per area per application is lower than the patch test threshold; furthermore the accumulated ROAT threshold is higher than the patch test threshold, which can probably be explained by the evaporation of HICC from the skin in the open test.

Chromatic Perceptual Learning but No Category Effects without Linguistic Input.

PubMed

Grandison, Alexandra; Sowden, Paul T; Drivonikou, Vicky G; Notman, Leslie A; Alexander, Iona; Davies, Ian R L

2016-01-01

Perceptual learning involves an improvement in perceptual judgment with practice, which is often specific to stimulus or task factors. Perceptual learning has been shown on a range of visual tasks but very little research has explored chromatic perceptual learning. Here, we use two low level perceptual threshold tasks and a supra-threshold target detection task to assess chromatic perceptual learning and category effects. Experiment 1 investigates whether chromatic thresholds reduce as a result of training and at what level of analysis learning effects occur. Experiment 2 explores the effect of category training on chromatic thresholds, whether training of this nature is category specific and whether it can induce categorical responding. Experiment 3 investigates the effect of category training on a higher level, lateralized target detection task, previously found to be sensitive to category effects. The findings indicate that performance on a perceptual threshold task improves following training but improvements do not transfer across retinal location or hue. Therefore, chromatic perceptual learning is category specific and can occur at relatively early stages of visual analysis. Additionally, category training does not induce category effects on a low level perceptual threshold task, as indicated by comparable discrimination thresholds at the newly learned hue boundary and adjacent test points. However, category training does induce emerging category effects on a supra-threshold target detection task. Whilst chromatic perceptual learning is possible, learnt category effects appear to be a product of left hemisphere processing, and may require the input of higher level linguistic coding processes in order to manifest.

Regression Discontinuity for Causal Effect Estimation in Epidemiology.

PubMed

Oldenburg, Catherine E; Moscoe, Ellen; Bärnighausen, Till

Regression discontinuity analyses can generate estimates of the causal effects of an exposure when a continuously measured variable is used to assign the exposure to individuals based on a threshold rule. Individuals just above the threshold are expected to be similar in their distribution of measured and unmeasured baseline covariates to individuals just below the threshold, resulting in exchangeability. At the threshold exchangeability is guaranteed if there is random variation in the continuous assignment variable, e.g., due to random measurement error. Under exchangeability, causal effects can be identified at the threshold. The regression discontinuity intention-to-treat (RD-ITT) effect on an outcome can be estimated as the difference in the outcome between individuals just above (or below) versus just below (or above) the threshold. This effect is analogous to the ITT effect in a randomized controlled trial. Instrumental variable methods can be used to estimate the effect of exposure itself utilizing the threshold as the instrument. We review the recent epidemiologic literature reporting regression discontinuity studies and find that while regression discontinuity designs are beginning to be utilized in a variety of applications in epidemiology, they are still relatively rare, and analytic and reporting practices vary. Regression discontinuity has the potential to greatly contribute to the evidence base in epidemiology, in particular on the real-life and long-term effects and side-effects of medical treatments that are provided based on threshold rules - such as treatments for low birth weight, hypertension or diabetes.

[Impacts of urban cooling effect based on landscape scale: a review].

PubMed

Yu, Zhao-wu; Guo, Qing-hai; Sun, Ran-hao

2015-02-01

The urban cooling island (UCI) effect is put forward in comparison with the urban heat island effect, and emphasizes on landscape planning for optimization of function and way of urban thermal environment. In this paper, we summarized current research of the UCI effects of waters, green space, and urban park from the perspective of patch area, landscape index, threshold value, landscape pattern and correlation analyses. Great controversy was found on which of the two factors patch area and shape index has a more significant impact, the quantification of UCI threshold is particularly lacking, and attention was paid too much on the UCI effect of landscape composition but little on that of landscape configuration. More attention should be paid on shape, width and location for water landscape, and on the type of green space, green area, configuration and management for green space landscape. The altitude of urban park and human activities could also influence UCI effect. In the future, the threshold determination should dominate the research of UCI effect, the reasons of controversy should be further explored, the study of time sequence should be strengthened, the UCI effects from landscape pattern and landscape configuration should be identified, and more attention should be paid to spatial scale and resolution for the precision and accuracy of the UCI results. Also, synthesizing the multidisciplinary research should be taken into consideration.

Compressively sampled MR image reconstruction using generalized thresholding iterative algorithm

NASA Astrophysics Data System (ADS)

Elahi, Sana; kaleem, Muhammad; Omer, Hammad

2018-01-01

Compressed sensing (CS) is an emerging area of interest in Magnetic Resonance Imaging (MRI). CS is used for the reconstruction of the images from a very limited number of samples in k-space. This significantly reduces the MRI data acquisition time. One important requirement for signal recovery in CS is the use of an appropriate non-linear reconstruction algorithm. It is a challenging task to choose a reconstruction algorithm that would accurately reconstruct the MR images from the under-sampled k-space data. Various algorithms have been used to solve the system of non-linear equations for better image quality and reconstruction speed in CS. In the recent past, iterative soft thresholding algorithm (ISTA) has been introduced in CS-MRI. This algorithm directly cancels the incoherent artifacts produced because of the undersampling in k -space. This paper introduces an improved iterative algorithm based on p -thresholding technique for CS-MRI image reconstruction. The use of p -thresholding function promotes sparsity in the image which is a key factor for CS based image reconstruction. The p -thresholding based iterative algorithm is a modification of ISTA, and minimizes non-convex functions. It has been shown that the proposed p -thresholding iterative algorithm can be used effectively to recover fully sampled image from the under-sampled data in MRI. The performance of the proposed method is verified using simulated and actual MRI data taken at St. Mary's Hospital, London. The quality of the reconstructed images is measured in terms of peak signal-to-noise ratio (PSNR), artifact power (AP), and structural similarity index measure (SSIM). The proposed approach shows improved performance when compared to other iterative algorithms based on log thresholding, soft thresholding and hard thresholding techniques at different reduction factors.

Comparison of salt taste thresholds and salt usage behaviours between adults in Myanmar and Korea.

PubMed

Cho, Hyungjin; Kim, So Mi; Jeong, Seong Su; Kim, Soon Bae

2016-12-01

Excessive oral salt intake can induce hypertension. According to previous studies, the prevalence of hypertension is higher in Myanmar than in Korea. We postulated that Myanmar adults had higher salt taste thresholds and eat much saltier food. This study aimed to compare salt taste thresholds and salt usage behaviour scores between adults in Myanmar and Korea. This cross-sectional study enrolled patients who visited volunteer medical service clinics at Ansung in Korea and Hlegu and Bago in Myanmar in August 2014. We measured the vital signs, heights, and weights of each patient and evaluated detection thresholds, recognition thresholds, and salt preferences. All patients underwent urinalysis and spot urine Na tests. Additionally, they each completed a salt usage behaviour questionnaire. A total of 131 patients were enrolled, including 64 Myanmarese patients and 67 Korean patients. Blood pressure was significantly higher in the Myanmarese than in the Koreans. Detection and recognition thresholds, salt preferences, and spot urine sodium and salt usage behaviour scores were also higher in the Myanmarese than in the Korean subjects. We calculated correlation coefficients between systolic blood pressure and parameters that were related to salt intake. The detection and recognition thresholds were significantly correlated with systolic blood pressure. All parameters related to salt intake, including detection and recognition thresholds, salt preference, salt usage behaviour scores and spot urine sodium concentrations, are significantly higher in Myanmarese than in Korean individuals.

Increased hs-CRP and decreased 1,25-dihydroxyvitamin D are associated with increased left ventricle lead threshold.

PubMed

Gözübüyük, Gökhan; Koç, Mevlüt; Kaypaklı, Onur; Şahin, Durmuş Yıldıray

2016-11-01

There are not enough data about threshold changes in patients with CRT. In this study, we aimed to investigate frequency of significant threshold increase of left ventricle lead and to determine clinical, demographic, medical and laboratory parameters that associated with threshold increase in CRT implanted patients. We included CRT implanted 200 patients (124 males, 76 females; mean age 65.8 ± 10.3 years) to this study. Basal and third month LV R wave amplitude, electrode impedance, and threshold values were recorded. Threshold increase was accepted as ≥0.1 V and significant increase as >1 V. Patients were divided into two groups: increased threshold and non-increased threshold for LV lead. Number of patients with increased LV threshold was 68 (37.6 %). Furthermore, 8 % of patients had severe increase (≥1 V) in LV threshold. We observed that serum levels of hs-CRP and 1,25 (OH)2 vitamin D were independently associated with increased LV threshold. We showed that 1 mg/dl increase in hs-CRP and the 1 mg/dl decrease in vitamin D are associated with 25.3 and 4.5 % increase in the odds of increased LV threshold, respectively. Increased hs-CRP and decreased 1,25 (OH)2 vitamin D are the strongest predictors of increased LV lead thresholds. We suggest that hs-CRP and 1,25 (OH)2 vitamin D may be used as markers to predict and follow the patients with increased thresholds. It may be useful to finalize CRT procedure with more appropriate basal threshold in patients with high serum hs-CRP and low 1,25 (OH)2 vitamin D levels.

T Cell Activation Thresholds are Affected by Gravitational

NASA Technical Reports Server (NTRS)

Adams, Charley; Gonzalez, M.; Nelman-Gonzalez, M.

1999-01-01

T cells stimulated in space flight by various mitogenic signals show a dramatic reduction in proliferation and expression of early activation markers. Similar results are also obtained in a ground based model of microgravity, clinorotation, which provides a vector-averaged reduction of the apparent gravity on cells without significant shear force. Here we demonstrate that T cell inhibition is due to an increase in the required threshold for activation. Dose response curves indicate that cells activated during clinorotation require higher stimulation to achieve the same level of activation, as measured by CD69 expression. Interleukin 2 receptor expression, and DNA synthesis. The amount of stimulation necessary for 50% activation is 5 fold in the clinostat relative to static. Correlation of TCR internalization with activation also exhibit a dramatic right shift in clinorotation, demonstrating unequivocally that signal transduction mechanism independent of TCR triggering account for the increased activation threshold. Previous results from space flight experiments are consistent with the dose response curves obtained for clinorotation. Activation thresholds are important aspects of T cell memory, autoimmunity and tolerance Clinorotation is a useful, noninvasive tool for the study of cellular and biochemical event regulating T cell activation threshold and the effects of gravitation forces on these systems.

On the need for a time- and location-dependent estimation of the NDSI threshold value for reducing existing uncertainties in snow cover maps at different scales

NASA Astrophysics Data System (ADS)

Härer, Stefan; Bernhardt, Matthias; Siebers, Matthias; Schulz, Karsten

2018-05-01

Knowledge of current snow cover extent is essential for characterizing energy and moisture fluxes at the Earth's surface. The snow-covered area (SCA) is often estimated by using optical satellite information in combination with the normalized-difference snow index (NDSI). The NDSI thereby uses a threshold for the definition if a satellite pixel is assumed to be snow covered or snow free. The spatiotemporal representativeness of the standard threshold of 0.4 is however questionable at the local scale. Here, we use local snow cover maps derived from ground-based photography to continuously calibrate the NDSI threshold values (NDSIthr) of Landsat satellite images at two European mountain sites of the period from 2010 to 2015. The Research Catchment Zugspitzplatt (RCZ, Germany) and Vernagtferner area (VF, Austria) are both located within a single Landsat scene. Nevertheless, the long-term analysis of the NDSIthr demonstrated that the NDSIthr at these sites are not correlated (r = 0.17) and different than the standard threshold of 0.4. For further comparison, a dynamic and locally optimized NDSI threshold was used as well as another locally optimized literature threshold value (0.7). It was shown that large uncertainties in the prediction of the SCA of up to 24.1 % exist in satellite snow cover maps in cases where the standard threshold of 0.4 is used, but a newly developed calibrated quadratic polynomial model which accounts for seasonal threshold dynamics can reduce this error. The model minimizes the SCA uncertainties at the calibration site VF by 50 % in the evaluation period and was also able to improve the results at RCZ in a significant way. Additionally, a scaling experiment shows that the positive effect of a locally adapted threshold diminishes using a pixel size of 500 m or larger, underlining the general applicability of the standard threshold at larger scales.

Comparison of the anticonvulsant potency of various diuretic drugs in the maximal electroshock-induced seizure threshold test in mice.

PubMed

Załuska, Katarzyna; Kondrat-Wróbel, Maria W; Łuszczki, Jarogniew J

2018-05-01

The coexistence of seizures and arterial hypertension requires an adequate and efficacious treatment involving both protection from seizures and reduction of high arterial blood pressure. Accumulating evidence indicates that some diuretic drugs (with a well-established position in the treatment of arterial hypertension) also possess anticonvulsant properties in various experimental models of epilepsy. The aim of this study was to assess the anticonvulsant potency of 6 commonly used diuretic drugs (i.e., amiloride, ethacrynic acid, furosemide, hydrochlorothiazide, indapamide, and spironolactone) in the maximal electroshock-induced seizure threshold (MEST) test in mice. Doses of the studied diuretics and their corresponding threshold increases were linearly related, allowing for the determination of doses which increase the threshold for electroconvulsions in drug-treated animals by 20% (TID20 values) over the threshold in control animals. Amiloride, hydrochlorothiazide and indapamide administered systemically (intraperitoneally - i.p.) increased the threshold for maximal electroconvulsions in mice, and the experimentally-derived TID20 values in the maximal electroshock seizure threshold test were 30.2 mg/kg for amiloride, 68.2 mg/kg for hydrochlorothiazide and 3.9 mg/kg for indapamide. In contrast, ethacrynic acid (up to 100 mg/kg), furosemide (up to 100 mg/kg) and spironolactone (up to 50 mg/kg) administered i.p. had no significant impact on the threshold for electroconvulsions in mice. The studied diuretics can be arranged with respect to their anticonvulsant potency in the MEST test as follows: indapamide > amiloride > hydrochlorothiazide. No anticonvulsant effects were observed for ethacrynic acid, furosemide or spironolactone in the MEST test in mice.

Distal small bowel bypass for weight regain after gastric bypass: safety and efficacy threshold occurs at <70% bypass.

PubMed

Caruana, Joseph A; Monte, Scott V; Jacobs, David M; Voytovich, Catherine; Ghanim, Husam; Dandona, Paresh

2015-01-01

For patients with poor weight loss (WL) after Roux-en-Y gastric bypass (RYGB) there are few well-tolerated and effective surgical options. Revision to distal bypass by shortening of the common channel (CC) induces significant WL but often produces protein calorie malnutrition (PCM) and severe diarrhea. The aim of this study was to identify a safe and effective threshold for distal small bowel bypass when done for revision of gastric bypass. Academic Institution, United States. We performed revision of RYGB for WL in 20 patients by shortening the CC to a new length of 120-300 cm. The Roux limb length was unchanged. WL and PCM were monitored. A threshold for percent of small bowel bypassed at which PCM was avoided was retrospectively determined. WL was then compared in patients above and below this threshold. Five patients completed a 250-kcal mixed meal challenge before and 3 months after revision to determine selected gut hormone responses. Bypassing ≥70% small bowel resulted in PCM in 4 of 10 patients but in none of 10 patients below that threshold. PCM was observed as late as 2 years after revision and necessitated rerevision by lengthening of the CC in 3 patients. Additionally, nocturnal diarrhea was more common and more intractable when ≥70% bypass was done. Both groups had significant excess body WL over 2 years, but it was greater in patients with ≥70% bypass (47±19 versus 26±17; P<.05). A favorable gut hormone response was observed with 3-hour decrease in glucose-dependent insulinotropic peptide (GIP) by 25% and increase in glucagon-like peptide-1 (GLP-1) by 25%, whereas fasting peptide-YY (PYY) increased by 71% (P<.05 for all). Revision of RYGB to distal bypass when it is <70% of a patient's small bowel length results in an acceptable balance of WL and a positive safety profile. WL may be mediated through an enhanced gut hormone effect, an aversion to ingested fat, and possibly other mechanisms. Copyright © 2015 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

Thresholds for decision-making: informing the cost-effectiveness and affordability of rotavirus vaccines in Malaysia.

PubMed

Loganathan, Tharani; Ng, Chiu-Wan; Lee, Way-Seah; Hutubessy, Raymond C W; Verguet, Stéphane; Jit, Mark

2018-03-01

Cost-effectiveness thresholds (CETs) based on the Commission on Macroeconomics and Health (CMH) are extensively used in low- and middle-income countries (LMICs) lacking locally defined CETs. These thresholds were originally intended for global and regional prioritization, and do not reflect local context or affordability at the national level, so their value for informing resource allocation decisions has been questioned. Using these thresholds, rotavirus vaccines are widely regarded as cost-effective interventions in LMICs. However, high vaccine prices remain a barrier towards vaccine introduction. This study aims to evaluate the cost-effectiveness, affordability and threshold price of universal rotavirus vaccination at various CETs in Malaysia. Cost-effectiveness of Rotarix and RotaTeq were evaluated using a multi-cohort model. Pan American Health Organization Revolving Fund's vaccine prices were used as tender price, while the recommended retail price for Malaysia was used as market price. We estimate threshold prices defined as prices at which vaccination becomes cost-effective, at various CETs reflecting economic theories of human capital, societal willingness-to-pay and marginal productivity. A budget impact analysis compared programmatic costs with the healthcare budget. At tender prices, both vaccines were cost-saving. At market prices, cost-effectiveness differed with thresholds used. At market price, using 'CMH thresholds', Rotarix programmes were cost-effective and RotaTeq were not cost-effective from the healthcare provider's perspective, while both vaccines were cost-effective from the societal perspective. Using other CETs, both vaccines were not cost-effective at market price, from the healthcare provider's and societal perspectives. At tender and cost-effective prices, rotavirus vaccination cost ∼1 and 3% of the public health budget, respectively. Using locally defined thresholds, rotavirus vaccination is cost-effective at vaccine prices in line with international tenders, but not at market prices. Thresholds representing marginal productivity are likely to be lower than those reflecting human capital and individual preference measures, and may be useful in determining affordable vaccine prices. © The Author 2017. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Vibration perception threshold for sight-threatening retinopathy screening in type 2 diabetic outpatients.

PubMed

Shen, Jing; Hu, Yanyun; Liu, Fang; Zeng, Hui; Li, Lianxi; Zhao, Jun; Zhao, Jungong; Zheng, Taishan; Lu, Huijuan; Lu, Fengdi; Bao, Yuqian; Jia, Weiping

2013-10-01

We investigated the relationship between vibration perception threshold and diabetic retinopathy and verified the screening value of vibration perception threshold for severe diabetic retinopathy. A total of 955 patients with type 2 diabetes were recruited and divided into three groups according to their fundus oculi photography results: no diabetic retinopathy (n = 654, 68.48%), non-sight-threatening diabetic retinopathy (n = 189, 19.79%) and sight-threatening diabetic retinopathy (n = 112, 11.73%). Their clinical and biochemical characteristics, vibration perception threshold and the diabetic retinopathy grades were detected and compared. There were significant differences in diabetes duration and blood glucose levels among three groups (all p < 0.05). The values of vibration perception threshold increased with the rising severity of retinopathy, and the vibration perception threshold level of sight-threatening diabetic retinopathy group was significantly higher than both non-sight-threatening diabetic retinopathy and no diabetic retinopathy groups (both p < 0.01). The prevalence of sight-threatening diabetic retinopathy in vibration perception threshold >25 V group was significantly higher than those in 16-24 V group (p < 0.01). The severity of diabetic retinopathy was positively associated with diabetes duration, blood glucose indexes and vibration perception threshold (all p < 0.01). Multiple stepwise regression analysis proved that glycosylated haemoglobin (β = 0.385, p = 0.000), diabetes duration (β = 0.275, p = 0.000) and vibration perception threshold (β = 0.180, p = 0.015) were independent risk factors for diabetic retinopathy. Receiver operating characteristic analysis further revealed that vibration perception threshold higher than 18 V was the optimal cut point for reflecting high risk of sight-threatening diabetic retinopathy (odds ratio = 4.20, 95% confidence interval = 2.67-6.59). There was a close association between vibration perception threshold and the severity of diabetic retinopathy. vibration perception threshold was a potential screening method for diabetic retinopathy, and its optimal cut-off for prompting high risk of sight-threatening retinopathy was 18 V. Copyright © 2013 John Wiley & Sons, Ltd.

The combined effects of transcutaneous electrical nerve stimulation (TENS) and stretching on muscle hardness and pressure pain threshold.

PubMed

Karasuno, Hiroshi; Ogihara, Hisayoshi; Morishita, Katsuyuki; Yokoi, Yuka; Fujiwara, Takayuki; Ogoma, Yoshiro; Abe, Koji

2016-04-01

[Purpose] This study aimed to clarify the immediate effects of a combined transcutaneous electrical nerve stimulation and stretching protocol. [Subjects] Fifteen healthy young males volunteered to participate in this study. The inclusion criterion was a straight leg raising range of motion of less than 70 degrees. [Methods] Subjects performed two protocols: 1) stretching (S group) of the medial hamstrings, and 2) tanscutaneous electrical nerve stimulation (100 Hz) with stretching (TS group). The TS group included a 20-minute electrical stimulation period followed by 10 minutes of stretching. The S group performed 10 minutes of stretching. Muscle hardness, pressure pain threshold, and straight leg raising range of motion were analyzed to evaluate the effects. The data were collected before transcutaneous electrical nerve stimulation (T1), before stretching (T2), immediately after stretching (T3), and 10 minutes after stretching (T4). [Results] Combined transcutaneous electrical nerve stimulation and stretching had significantly beneficial effects on muscle hardness, pressure pain threshold, and straight leg raising range of motion at T2, T3, and T4 compared with T1. [Conclusion] These results support the belief that transcutaneous electrical nerve stimulation combined with stretching is effective in reducing pain and decreasing muscle hardness, thus increasing range of motion.

Lead exposure potentiates predatory attack behavior in the cat.

PubMed

Li, Wenjie; Han, Shenggao; Gregg, Thomas R; Kemp, Francis W; Davidow, Amy L; Louria, Donald B; Siegel, Allan; Bogden, John D

2003-07-01

Epidemiologic studies have demonstrated that environmental lead exposure is associated with aggressive behavior in children; however, numerous confounding variables limit the ability of these studies to establish a causal relationship. The study of aggressive behavior using a validated animal model was used to test the hypothesis that there is a causal relationship between lead exposure and aggression in the absence of confounding variables. We studied the effects of lead exposure on a feline model of aggression: predatory (quiet biting) attack of an anesthetized rat. Five cats were stimulated with a precisely controlled electrical current via electrodes inserted into the lateral hypothalamus. The response measure was the predatory attack threshold current (i.e., the current required to elicit an attack response on 50% of the trials). Blocks of trials were administered in which predatory attack threshold currents were measured three times a week for a total of 6-10 weeks, including before, during, and after lead exposure. Lead was incorporated into cat food "treats" at doses of 50-150 mg/kg/day. Two of the five cats received a second period of lead exposure. Blood lead concentrations were measured twice a week and were <1, 21-77, and <20 micro g/dL prior to, during, and after lead exposure, respectively. The predatory attack threshold decreased significantly during initial lead exposure in three of five cats and increased after the cessation of lead exposure in four of the five cats (P<0.01). The predatory attack thresholds and blood lead concentrations for each cat were inversely correlated (r=-0.35 to -0.74). A random-effects mixed model demonstrated a significant (P=0.0019) negative association between threshold current and blood lead concentration. The data of this study demonstrate that lead exposure enhances predatory aggression in the cat and provide experimental support for a causal relationship between lead exposure and aggressive behavior in humans.

Nonlinear threshold effect in the Z-scan method of characterizing limiters for high-intensity laser light

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tereshchenko, S. A., E-mail: tsa@miee.ru; Savelyev, M. S.; Podgaetsky, V. M.

A threshold model is described which permits one to determine the properties of limiters for high-powered laser light. It takes into account the threshold characteristics of the nonlinear optical interaction between the laser beam and the limiter working material. The traditional non-threshold model is a particular case of the threshold model when the limiting threshold is zero. The nonlinear characteristics of carbon nanotubes in liquid and solid media are obtained from experimental Z-scan data. Specifically, the nonlinear threshold effect was observed for aqueous dispersions of nanotubes, but not for nanotubes in solid polymethylmethacrylate. The threshold model fits the experimental Z-scanmore » data better than the non-threshold model. Output characteristics were obtained that integrally describe the nonlinear properties of the optical limiters.« less

Dynamic shear-stress-enhanced rates of nutrient consumption in gas-liquid semi-continuous-flow suspensions

NASA Astrophysics Data System (ADS)

Belfiore, Laurence A.; Volpato, Fabio Z.; Paulino, Alexandre T.; Belfiore, Carol J.

2011-12-01

The primary objective of this investigation is to establish guidelines for generating significant mammalian cell density in suspension bioreactors when stress-sensitive kinetics enhance the rate of nutrient consumption. Ultra-low-frequency dynamic modulations of the impeller (i.e., 35104 Hz) introduce time-dependent oscillatory shear into this transient analysis of cell proliferation under semi-continuous creeping flow conditions. Greater nutrient consumption is predicted when the amplitude A of modulated impeller rotation increases, and stress-kinetic contributions to nutrient consumption rates increase linearly at higher modulation frequency via an application of fluctuation-dissipation response. Interphase mass transfer is required to replace dissolved oxygen as it is consumed by aerobic nutrient consumption in the liquid phase. The theory and predictions described herein could be important at small length scales in the creeping flow regime where viscous shear is significant at the interface between the nutrient medium and isolated cells in suspension. Two-dimensional flow around spherically shaped mammalian cells, suspended in a Newtonian culture medium, is analyzed to calculate the surface-averaged magnitude of the velocity gradient tensor and modify homogeneous rates of nutrient consumption that are stimulated by viscous shear, via the formalism of stress-kinetic reciprocal relations that obey Curie's theorem in non-equilibrium thermodynamics. Time constants for stress-free free and stress-sensitive stress nutrient consumption are defined and quantified to identify the threshold (i.e., stress,threshold) below which the effect of stress cannot be neglected in accurate predictions of bioreactor performance. Parametric studies reveal that the threshold time constant for stress-sensitive nutrient consumption stress,threshold decreases when the time constant for stress-free nutrient consumption free is shorter. Hence, stress,threshold depends directly on free. In other words, the threshold rate of stress-sensitive nutrient consumption is higher when the stress-free rate of nutrient consumption increases. Modulated rotation of the impeller, superimposed on steady shear, increases stress,threshold when free is constant, and stress,threshold depends directly on the amplitude A of these angular velocity modulations.

Colour perception with changes in levels of illumination

NASA Astrophysics Data System (ADS)

Baah, Kwame F.; Green, Phil; Pointer, Michael

2012-01-01

The perceived colour of a stimulus depends on the conditions under which it is viewed. For colours employed as an important cue or identifier, such as signage and brand colours, colour reproduction tolerances are critically important. Typically, such stimuli would be judged using a known level of illumination but, in the target environment, the level of illumination used to view the samples may be entirely different. The effect of changes in the viewing condition on the perceptibility and acceptability of small colour differences should be understood when such tolerances and associated viewing conditions, are specified. A series of psychophysical experiments was conducted to determine whether changes in illumination level significantly alter acceptability and perceptibility thresholds of uniform colour stimuli. It was found that perceived colour discrimination thresholds varied by up to 2.0 ΔE00. For the perceptual correlate of hue however, this value could be of significance if the accepted error of colour difference was at the threshold, thereby yielding the possibility of rejection with changes in illumination level. Lightness and chroma on the other hand, exhibited greater tolerance and were less likely to be rejected with illuminance changes.

Microplastic Effect Thresholds for Freshwater Benthic Macroinvertebrates

PubMed Central

2018-01-01

Now that microplastics have been detected in lakes, rivers, and estuaries all over the globe, evaluating their effects on biota has become an urgent research priority. This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates with different species traits, using a wide range of microplastic concentrations. Standardized 28 days single species bioassays were performed under environmentally relevant exposure conditions using polystyrene microplastics (20–500 μm) mixed with sediment at concentrations ranging from 0 to 40% sediment dry weight (dw). Microplastics caused no effects on the survival of Gammarus pulex, Hyalella azteca, Asellus aquaticus, Sphaerium corneum, and Tubifex spp. and no effects were found on the reproduction of Lumbriculus variegatus. No significant differences in growth were found for H. azteca, A. aquaticus, S. corneum, L. variegatus, and Tubifex spp. However, G. pulex showed a significant reduction in growth (EC10 = 1.07% sediment dw) and microplastic uptake was proportional with microplastic concentrations in sediment. These results indicate that although the risks of environmentally realistic concentrations of microplastics may be low, they still may affect the biodiversity and the functioning of aquatic communities which after all also depend on the sensitive species. PMID:29337537

Microplastic Effect Thresholds for Freshwater Benthic Macroinvertebrates.

PubMed

Redondo-Hasselerharm, Paula E; Falahudin, Dede; Peeters, Edwin T H M; Koelmans, Albert A

2018-02-20

Now that microplastics have been detected in lakes, rivers, and estuaries all over the globe, evaluating their effects on biota has become an urgent research priority. This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates with different species traits, using a wide range of microplastic concentrations. Standardized 28 days single species bioassays were performed under environmentally relevant exposure conditions using polystyrene microplastics (20-500 μm) mixed with sediment at concentrations ranging from 0 to 40% sediment dry weight (dw). Microplastics caused no effects on the survival of Gammarus pulex, Hyalella azteca, Asellus aquaticus, Sphaerium corneum, and Tubifex spp. and no effects were found on the reproduction of Lumbriculus variegatus. No significant differences in growth were found for H. azteca, A. aquaticus, S. corneum, L. variegatus, and Tubifex spp. However, G. pulex showed a significant reduction in growth (EC 10 = 1.07% sediment dw) and microplastic uptake was proportional with microplastic concentrations in sediment. These results indicate that although the risks of environmentally realistic concentrations of microplastics may be low, they still may affect the biodiversity and the functioning of aquatic communities which after all also depend on the sensitive species.

Anesthesia modifies subthreshold critical slowing down in a stochastic Hodgkin-Huxley-like model with inhibitory synaptic input

NASA Astrophysics Data System (ADS)

Bukoski, Alex; Steyn-Ross, D. A.; Pickett, Ashley F.; Steyn-Ross, Moira L.

2018-06-01

The dynamics of a stochastic type-I Hodgkin-Huxley-like point neuron model exposed to inhibitory synaptic noise are investigated as a function of distance from spiking threshold and the inhibitory influence of the general anesthetic agent propofol. The model is biologically motivated and includes the effects of intrinsic ion-channel noise via a stochastic differential equation description as well as inhibitory synaptic noise modeled as multiple Poisson-distributed impulse trains with saturating response functions. The effect of propofol on these synapses is incorporated through this drug's principal influence on fast inhibitory neurotransmission mediated by γ -aminobutyric acid (GABA) type-A receptors via reduction of the synaptic response decay rate. As the neuron model approaches spiking threshold from below, we track membrane voltage fluctuation statistics of numerically simulated stochastic trajectories. We find that for a given distance from spiking threshold, increasing the magnitude of anesthetic-induced inhibition is associated with augmented signatures of critical slowing: fluctuation amplitudes and correlation times grow as spectral power is increasingly focused at 0 Hz. Furthermore, as a function of distance from threshold, anesthesia significantly modifies the power-law exponents for variance and correlation time divergences observable in stochastic trajectories. Compared to the inverse square root power-law scaling of these quantities anticipated for the saddle-node bifurcation of type-I neurons in the absence of anesthesia, increasing anesthetic-induced inhibition results in an observable exponent <-0.5 for variance and >-0.5 for correlation time divergences. However, these behaviors eventually break down as distance from threshold goes to zero with both the variance and correlation time converging to common values independent of anesthesia. Compared to the case of no synaptic input, linearization of an approximating multivariate Ornstein-Uhlenbeck model reveals these effects to be the consequence of an additional slow eigenvalue associated with synaptic activity that competes with those of the underlying point neuron in a manner that depends on distance from spiking threshold.

The fragmentation threshold and implications for explosive eruptions

NASA Astrophysics Data System (ADS)

Kennedy, B.; Spieler, O.; Kueppers, U.; Scheu, B.; Mueller, S.; Taddeucci, J.; Dingwell, D.

2003-04-01

The fragmentation threshold is the minimum pressure differential required to cause a porous volcanic rock to form pyroclasts. This is a critical parameter when considering the shift from effusive to explosive eruptions. We fragmented a variety of natural volcanic rock samples at room temperature (20oC) and high temperature (850oC) using a shock tube modified after Aldibirov and Dingwell (1996). This apparatus creates a pressure differential which drives fragmentation. Pressurized gas in the vesicles of the rock suddenly expands, blowing the sample apart. For this reason, the porosity is the primary control on the fragmentation threshold. On a graph of porosity against fragmentation threshold, our results from a variety of natural samples at both low and high temperatures all plot on the same curve and show the threshold increasing steeply at low porosities. A sharp decrease in the fragmentation threshold occurs as porosity increases from 0- 15%, while a more gradual decrease is seen from 15- 85%. The high temperature experiments form a curve with less variability than the low temperature experiments. For this reason, we have chosen to model the high temperature thresholds. The curve can be roughly predicted by the tensile strength of glass (140 MPa) divided by the porosity. Fractured phenocrysts in the majority of our samples reduces the overall strength of the sample. For this reason, the threshold values can be more accurately predicted by % matrix x the tensile strength/ porosity. At very high porosities the fragmentation threshold varies significantly due to the effect of bubble shape and size distributions on the permeability (Mueller et al, 2003). For example, high thresholds are seen for samples with very high permeabilities, where gas flow reduces the local pressure differential. These results allow us to predict the fragmentation threshold for any volcanic rock for which the porosity and crystal contents are known. During explosive eruptions, the fragmentation threshold may be exceeded in two ways: (1) by building an overpressure within the vesicles above the fragmentation threshold or (2) by unloading and exposing lithostatically pressurised magma to lower pressures. Using this data, we can in principle estimate the height of dome collapse or amount of overpressure necessary to produce an explosive eruption.

Effects of acute L-carnitine intake on metabolic and blood lactate levels of elite badminton players.

PubMed

Eroğlu, Hüseyin; Senel, Omer; Güzel, Nevin A

2008-04-01

Purpose of this study is to research the effects of acute L-Carnitine intake on badminton players' metabolic and blood lactate values. A total of 16 Turkish national badminton players (8 male, 8 female) were voluntarily participated into study. MaxVO2, MET, energy consumption, HR (heart rate), VE (minute ventilation), R (respiratory exchange ratio), AT (anaerobic threshold), oxygen pulse and blood lactate (LA) of subjects were measured by Sensormedics VmaxST and Accutrend Lactate Analyzer. The participants were subjected to the test protocol twice before and after 2g of L-Carnitine intake. The data were evaluated by the use of SPSS 13.0 for Windows. No significant differences were found between 1st. (without L-Carnitine intake) and 2nd. (with L-Carnitine intake) measurements of female participants as regards to all measured parameters. There was a significant difference in EMHR (exercise maximum heart rate) of males between two measurements (p<0.05). However the differences in other parameters were not significant. AT values of female subjects were not significant difference (p>0.05). Respiratory exchange ratio of males was significantly different at anaerobic threshold (p<0.05). Results of this study show that L-carnitine intake one hour prior to the exercise has no effect on the metabolic and blood lactate values of badminton players.

Iterative cross section sequence graph for handwritten character segmentation.

PubMed

Dawoud, Amer

2007-08-01

The iterative cross section sequence graph (ICSSG) is an algorithm for handwritten character segmentation. It expands the cross section sequence graph concept by applying it iteratively at equally spaced thresholds. The iterative thresholding reduces the effect of information loss associated with image binarization. ICSSG preserves the characters' skeletal structure by preventing the interference of pixels that causes flooding of adjacent characters' segments. Improving the structural quality of the characters' skeleton facilitates better feature extraction and classification, which improves the overall performance of optical character recognition (OCR). Experimental results showed significant improvements in OCR recognition rates compared to other well-established segmentation algorithms.

Performance breakdown in optimal stimulus decoding

NASA Astrophysics Data System (ADS)

Kostal, Lubomir; Lansky, Petr; Pilarski, Stevan

2015-06-01

Objective. One of the primary goals of neuroscience is to understand how neurons encode and process information about their environment. The problem is often approached indirectly by examining the degree to which the neuronal response reflects the stimulus feature of interest. Approach. In this context, the methods of signal estimation and detection theory provide the theoretical limits on the decoding accuracy with which the stimulus can be identified. The Cramér-Rao lower bound on the decoding precision is widely used, since it can be evaluated easily once the mathematical model of the stimulus-response relationship is determined. However, little is known about the behavior of different decoding schemes with respect to the bound if the neuronal population size is limited. Main results. We show that under broad conditions the optimal decoding displays a threshold-like shift in performance in dependence on the population size. The onset of the threshold determines a critical range where a small increment in size, signal-to-noise ratio or observation time yields a dramatic gain in the decoding precision. Significance. We demonstrate the existence of such threshold regions in early auditory and olfactory information coding. We discuss the origin of the threshold effect and its impact on the design of effective coding approaches in terms of relevant population size.

The Actions of Lyophilized Apple Peel on the Electrical Activity and Organization of the Ventricular Syncytium of the Hearts of Diabetic Rats

PubMed Central

Martínez-Ladrón de Guevara, Elideth; Pérez-Hernández, Nury; Villalobos-López, Miguel Ángel; Pérez-Ishiwara, David Guillermo; Salas-Benito, Juan Santiago; Martínez Martínez, Alejandro; Hernández-García, Vicente

2016-01-01

This study was designed to examine the effects of lyophilized red delicious apple peel (RDP) on the action potentials (APs) and the input resistance-threshold current relationship. The experiments were performed on isolated papillary heart muscles from healthy male rats, healthy male rats treated with RDP, diabetic male rats, and diabetic male rats treated with RDP. The preparation was superfused with oxygenated Tyrode's solution at 37°C. The stimulation and the recording of the APs, the input resistance, and the threshold current were made using conventional electrophysiological methods. The RDP presented no significant effect in normal rats. Equivalent doses in diabetic rats reduced the APD and ARP. The relationship between input resistance and threshold current established an inverse correlation. The results indicate the following: (1) The functional structure of the cardiac ventricular syncytium in healthy rats is heterogeneous, in terms of input resistance and threshold current. Diabetes further accentuates the heterogeneity. (2) As a consequence, conduction block occurs and increases the possibility of reentrant arrhythmias. (3) These modifications in the ventricular syncytium, coupled with the increase in the ARP, are the adequate substrate so that, with diabetes, the heart becomes more arrhythmogenic. (4) RDP decreases the APD, the ARP, and most syncytium irregularity caused by diabetes. PMID:26839897

You Spin my Head Right Round: Threshold of Limited Immersion for Rotation Gains in Redirected Walking.

PubMed

Schmitz, Patric; Hildebrandt, Julian; Valdez, Andre Calero; Kobbelt, Leif; Ziefle, Martina

2018-04-01

In virtual environments, the space that can be explored by real walking is limited by the size of the tracked area. To enable unimpeded walking through large virtual spaces in small real-world surroundings, redirection techniques are used. These unnoticeably manipulate the user's virtual walking trajectory. It is important to know how strongly such techniques can be applied without the user noticing the manipulation-or getting cybersick. Previously, this was estimated by measuring a detection threshold (DT) in highly-controlled psychophysical studies, which experimentally isolate the effect but do not aim for perceived immersion in the context of VR applications. While these studies suggest that only relatively low degrees of manipulation are tolerable, we claim that, besides establishing detection thresholds, it is important to know when the user's immersion breaks. We hypothesize that the degree of unnoticed manipulation is significantly different from the detection threshold when the user is immersed in a task. We conducted three studies: a) to devise an experimental paradigm to measure the threshold of limited immersion (TLI), b) to measure the TLI for slowly decreasing and increasing rotation gains, and c) to establish a baseline of cybersickness for our experimental setup. For rotation gains greater than 1.0, we found that immersion breaks quite late after the gain is detectable. However, for gains lesser than 1.0, some users reported a break of immersion even before established detection thresholds were reached. Apparently, the developed metric measures an additional quality of user experience. This article contributes to the development of effective spatial compression methods by utilizing the break of immersion as a benchmark for redirection techniques.

Mechanisms of breathing instability in patients with obstructive sleep apnea.

PubMed

Younes, Magdy; Ostrowski, Michele; Atkar, Raj; Laprairie, John; Siemens, Andrea; Hanly, Patrick

2007-12-01

The response to chemical stimuli (chemical responsiveness) and the increases in respiratory drive required for arousal (arousal threshold) and for opening the airway without arousal (effective recruitment threshold) are important determinants of ventilatory instability and, hence, severity of obstructive apnea. We measured these variables in 21 obstructive apnea patients (apnea-hypopnea index 91 +/- 24 h(-1)) while on continuous-positive-airway pressure. During sleep, pressure was intermittently reduced (dial down) to induce severe hypopneas. Dial downs were done on room air and following approximately 30 s of breathing hypercapneic and/or hypoxic mixtures, which induced a range of ventilatory stimulation before dial down. Ventilation just before dial down and flow during dial down were measured. Chemical responsiveness, estimated as the percent increase in ventilation during the 5(th) breath following administration of 6% CO(2) combined with approximately 4% desaturation, was large (187 +/- 117%). Arousal threshold, estimated as the percent increase in ventilation associated with a 50% probability of arousal, ranged from 40% to >268% and was <120% in 12/21 patients, indicating that in many patients arousal occurs with modest changes in chemical drive. Effective recruitment threshold, estimated as percent increase in pre-dial-down ventilation associated with a significant increase in dial-down flow, ranged from zero to >174% and was <110% in 12/21 patients, indicating that in many patients reflex dilatation occurs with modest increases in drive. The two thresholds were not correlated. In most OSA patients, airway patency may be maintained with only modest increases in chemical drive, but instability results because of a low arousal threshold and a brisk increase in drive following brief reduction in alveolar ventilation.

The effectiveness of Kinesio Taping on pain and disability in cervical myofascial pain syndrome.

PubMed

Ay, Saime; Konak, Hatice Ecem; Evcik, Deniz; Kibar, Sibel

The aim of this study was to investigate the effectiveness of Kinesio Taping and sham Kinesio Taping on pain, pressure pain threshold, cervical range of motion, and disability in cervical myofascial pain syndrome patients (MPS). This study was designed as a randomized, double-blind placebo controlled study. Sixty-one patients with MPS were randomly assigned into two groups. Group 1 (n=31) was treated with Kinesio Taping and group 2 (n=30) was treated sham taping five times by intervals of 3 days for 15 days. Additionally, all patients were given neck exercise program. Patients were evaluated according to pain, pressure pain threshold, cervical range of motion and disability. Pain was assessed by using Visual Analog Scale, pressure pain threshold was measured by using an algometer, and active cervical range of motion was measured by using goniometry. Disability was assessed with the neck pain disability index disability. Measurements were taken before and after the treatment. At the end of the therapy, there were statistically significant improvements on pain, pressure pain threshold, cervical range of motion, and disability (p<0.05) in both groups. Also there was a statistical difference between the groups regarding pain, pressure pain threshold, cervical flexion-extension (p<0.05); except cervical rotation, cervical lateral flexion and disability (p>0.05). This study shows that Kinesio Taping leads to improvements on pain, pressure pain threshold and cervical range of motion, but not disability in short time. Therefore, Kinesio Taping can be used as an alternative therapy method in the treatment of patients with MPS. Copyright © 2016 Elsevier Editora Ltda. All rights reserved.

The interplay between cooperativity and diversity in model threshold ensembles.

PubMed

Cervera, Javier; Manzanares, José A; Mafe, Salvador

2014-10-06

The interplay between cooperativity and diversity is crucial for biological ensembles because single molecule experiments show a significant degree of heterogeneity and also for artificial nanostructures because of the high individual variability characteristic of nanoscale units. We study the cross-effects between cooperativity and diversity in model threshold ensembles composed of individually different units that show a cooperative behaviour. The units are modelled as statistical distributions of parameters (the individual threshold potentials here) characterized by central and width distribution values. The simulations show that the interplay between cooperativity and diversity results in ensemble-averaged responses of interest for the understanding of electrical transduction in cell membranes, the experimental characterization of heterogeneous groups of biomolecules and the development of biologically inspired engineering designs with individually different building blocks. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Temporal discrimination threshold with healthy aging.

PubMed

Ramos, Vesper Fe Marie Llaneza; Esquenazi, Alina; Villegas, Monica Anne Faye; Wu, Tianxia; Hallett, Mark

2016-07-01

The temporal discrimination threshold (TDT) is the shortest interstimulus interval at which a subject can perceive successive stimuli as separate. To investigate the effects of aging on TDT, we studied tactile TDT using the method of limits with 120% of sensory threshold in each hand for each of 100 healthy volunteers, equally divided among men and women, across 10 age groups, from 18 to 79 years. Linear regression analysis showed that age was significantly related to left-hand mean, right-hand mean, and mean of 2 hands with R-square equal to 0.08, 0.164, and 0.132, respectively. Reliability analysis indicated that the 3 measures had fair-to-good reliability (intraclass correlation coefficient: 0.4-0.8). We conclude that TDT is affected by age and has fair-to-good reproducibility using our technique. Published by Elsevier Inc.

The effects of a rise in cigarette price on cigarette consumption, tobacco taxation revenues, and of smoking-related deaths in 28 EU countries-- applying threshold regression modelling.

PubMed

Yeh, Chun-Yuan; Schafferer, Christian; Lee, Jie-Min; Ho, Li-Ming; Hsieh, Chi-Jung

2017-09-21

European Union public healthcare expenditure on treating smoking and attributable diseases is estimated at over €25bn annually. The reduction of tobacco consumption has thus become one of the major social policies of the EU. This study investigates the effects of price hikes on cigarette consumption, tobacco tax revenues and smoking-caused deaths in 28 EU countries. Employing panel data for the years 2005 to 2014 from Euromonitor International, the World Bank and the World Health Organization, we used income as a threshold variable and applied threshold regression modelling to estimate the elasticity of cigarette prices and to simulate the effect of price fluctuations. The results showed that there was an income threshold effect on cigarette prices in the 28 EU countries that had a gross national income (GNI) per capita lower than US$5418, with a maximum cigarette price elasticity of -1.227. The results of the simulated analysis showed that a rise of 10% in cigarette price would significantly reduce cigarette consumption as well the total death toll caused by smoking in all the observed countries, but would be most effective in Bulgaria and Romania, followed by Latvia and Poland. Additionally, an increase in the number of MPOWER tobacco control policies at the highest level of achievment would help reduce cigarette consumption. It is recommended that all EU countries levy higher tobacco taxes to increase cigarette prices, and thus in effect reduce cigarette consumption. The subsequent increase in tobacco tax revenues would be instrumental in covering expenditures related to tobacco prevention and control programs.

76 FR 67067 - Approval and Promulgation of Implementation Plans; Iowa: Prevention of Significant Deterioration...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-31

... thresholds for GHG emissions in Iowa's PSD and Title V regulations at the same emissions thresholds and in... sources emitting less than these thresholds will not be subject to permitting requirements for GHGs that they emit. The amendments to the SIP clarify the applicable thresholds in the Iowa SIP, address the...

A Specimen Size Effect on the Fatigue Crack Growth Rate Threshold of IN 718

NASA Technical Reports Server (NTRS)

Garr, K. R.; Hresko, G. C., III

1998-01-01

Fatigue crack growth rate (FCGR) tests were conducted on IN 718 in the solution annealed and aged condition at room temperature in accordance with E647-87. As part of each test, the FCGR threshold was measured using the decreasing Delta K method. A new heat of material was being tested and some of this material was sent to a different laboratory which wanted to use a specimen with a 127 mm width. Threshold data previously had been established on specimens with a width of 50.8 mm. As a check of the laboratory, tests were conducted at room temperature and R equal to 0.1 for comparison with the earlier data. The results were a threshold significantly higher than previously observed. Interchanging of specimen sizes and laboratories showed that the results were not due to a heat-to-heat or lab-to-lab variation. The results to be presented here are those obtained at the original laboratory. Growth rates were measured using the electric potential drop technique at R values of 0.1, 0.7, and 0.9. Compact tension specimen sizes with planer dimensions of 25.4 mm, 50.8 mm, and 127 mm were used. Crack growth rates at threshold were generally below 2.5 X 10(exp -8) mm / cycle. Closure measurements were made on some of the specimens by a manual procedure using a clip gage. When the crack growth rate data for the specimens tested at R equal to 0.1 were plotted as a function of applied Delta K, the thresholds varied with specimen width. The larger the width, the higher the threshold. The thresholds varied from 6.5 MPa-m(exp 1/2) for the 25.4 mm specimen to 15.4 MPa-m(exp 1/2) for the 127 mm specimen. At R equal to 0.7, the 25.4 mm and 50.8 mm specimens had essentially the same threshold, about 2.9 MPa-m(exp 1/2)while the 127 mm specimen had a threshold of 4.5 MPa-m(exp 1/2). When plotted as a function of effective Delta K, the R equal to 0.1 data are essentially normalized. Various aspects of the test procedure will be discussed as well as the results of analysis of the data using some different closure models.

Is the Functional Threshold Power (FTP) a Valid Surrogate of the Lactate Threshold?

PubMed

Valenzuela, Pedro L; Morales, Javier S; Foster, Carl; Lucia, Alejandro; de la Villa, Pedro

2018-05-10

This study aimed to analyze the relationship between the Functional Threshold Power (FTP) and the Lactate Threshold (LT). 20 male cyclists performed an incremental test in which the LT was determined. At least 48 h later, they performed a 20-minute time trial and 95% of the mean power output (P20) was defined as FTP. Participants were divided into recreational (Peak Power Output [PPO] < 4.5 W∙kg -1 , n=11) or trained cyclists (PPO > 4.5 W∙kg -1 , n=9) according to their fitness status. The FTP (240 ± 35 W) was overall not significantly different (effect size[ES]=0.20, limits of agreement [LoA]=-2.4 ± 11.5%) from the LT (246 ± 24 W), and both markers were strongly correlated (r=0.95, p<0.0001). Accounting for the participants' fitness status, no significant differences were found between FTP and LT ([ES]=0.22; LoA=2.1 ± 7.8%) in TC, but FTP was significantly lower than the LT (p=0.0004, ES=0.81; LoA=-6.5 ± 8.3%) in RC. A significant relationship was found between relative PPO and the bias between FTP and the LT markers (r=0.77, p<0.0001). The FTP is a valid field test-based marker for the assessment of endurance fitness. However, caution should be taken when using the FTP interchangeably with the LT as the bias between markers seems to depend on the athletes' fitness status. Whereas the FTP provides a good estimate of the LT in trained cyclists, in recreational cyclists FTP may underestimate LT.

Nociceptive Response to L-DOPA-Induced Dyskinesia in Hemiparkinsonian Rats.

PubMed

Nascimento, G C; Bariotto-Dos-Santos, K; Leite-Panissi, C R A; Del-Bel, E A; Bortolanza, M

2018-04-02

Non-motor symptoms are increasingly identified to present clinical and diagnostic importance for Parkinson's disease (PD). The multifactorial origin of pain in PD makes this symptom of great complexity. The dopamine precursor, L-DOPA (L-3,4-dihydroxyphenylalanine), the classic therapy for PD, seems to be effective in pain threshold; however, there are no studies correlating L-DOPA-induced dyskinesia (LID) and nociception development in experimental Parkinsonism. Here, we first investigated nociceptive responses in a 6-hydroxydopamine (6-OHDA)-lesioned rat model of Parkinson's disease to a hind paw-induced persistent inflammation. Further, the effect of L-DOPA on nociception behavior at different times of treatment was investigated. Pain threshold was determined using von Frey and Hot Plate/Tail Flick tests. Dyskinesia was measured by abnormal involuntary movements (AIMs) induced by L-DOPA administration. This data is consistent to show that 6-OHDA-lesioned rats had reduced nociceptive thresholds compared to non-lesioned rats. Additionally, when these rats were exposed to a persistent inflammatory challenge, we observed increased hypernociceptive responses, namely hyperalgesia. L-DOPA treatment alleviated pain responses on days 1 and 7 of treatment, but not on day 15. During that period, we observed an inverse relationship between LID and nociception threshold in these rats, with a high LID rate corresponding to a reduced nociception threshold. Interestingly, pain responses resulting from CFA-induced inflammation were significantly enhanced during established dyskinesia. These data suggest a pro-algesic effect of L-DOPA-induced dyskinesia, which is confirmed by the correlation founded here between AIMs and nociceptive indexes. In conclusion, our results are consistent with the notion that central dopaminergic mechanism is directly involved in nociceptive responses in Parkinsonism condition.

Cone-beam computed tomography in children with cochlear implants: The effect of electrode array position on ECAP.

PubMed

Lathuillière, Marine; Merklen, Fanny; Piron, Jean-Pierre; Sicard, Marielle; Villemus, Françoise; Menjot de Champfleur, Nicolas; Venail, Frédéric; Uziel, Alain; Mondain, Michel

2017-01-01

To assess the feasibility of using cone-beam computed tomography (CBCT) in young children with cochlear implants (CIs) and study the effect of intracochlear position on electrophysiological and behavioral measurements. A total of 40 children with either unilateral or bilateral cochlear implants were prospectively included in the study. Electrode placement and insertion angles were studied in 55 Cochlear ® implants (16 straight arrays and 39 perimodiolar arrays), using either CBCT or X-ray imaging. CBCT or X-ray imaging were scheduled when the children were leaving the recovery room. We recorded intraoperative and postoperative neural response telemetry threshold (T-NRT) values, intraoperative and postoperative electrode impedance values, as well as behavioral T (threshold) and C (comfort) levels on electrodes 1, 5, 10, 15 and 20. CBCT imaging was feasible without any sedation in 24 children (60%). Accidental scala vestibuli insertion was observed in 3 out of 24 implants as assessed by CBCT. The mean insertion angle was 339.7°±35.8°. The use of a perimodiolar array led to higher angles of insertion, lower postoperative T-NRT, as well as decreased behavioral T and C levels. We found no significant effect of either electrode array position or angle of insertion on electrophysiological data. CBCT appears to be a reliable tool for anatomical assessment of young children with CIs. Intracochlear position had no significant effect on the electrically evoked compound action potential (ECAP) threshold. Our CBCT protocol must be improved to increase the rate of successful investigations. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Age-dependent effects of topiramate on the acquisition and the retention of rapid kindling.

PubMed

Mazarati, Andréy; Shin, Don; Auvin, Stéphane; Sankar, Raman

2007-04-01

To examine antiepileptogenic, disease modifying, and anticonvulsant effects of topiramate under conditions of rapid kindling at different stages of development. Afterdischarge threshold (ADT) and duration (ADD) were examined in 2-, 3-, and 5-week-old Wistar rats before and after administration of topiramate (200 mg/kg). Animals underwent a rapid kindling protocol (sixty 10-s trains, bipolar 20 Hz square wave pulses delivered every 5 min). The progression of behavioral and electrographic seizures, and responses to test stimulations 24 h after the protocol were compared between topiramate and vehicle-treated control rats. In addition, rats that were previously given vehicle only prior to kindling, were then given topiramate to examine the effect on established kindled seizures. In 2-week-old animals, topiramate affected neither the baseline afterdischarge, nor the progression of kindled seizures. In 3-week-old rats, topiramate did not modify the baseline afterdischarge, but significantly delayed the occurrence of full motor seizures in response to repeated stimulations. Topiramate treatment of 5-week-old rats increased baseline ADT, shortened ADD, and delayed the progression of kindled seizures. Twenty-four h after the last kindling stimulation, animals of all ages exhibited a decreased ADT, an increase ADD, and developed behavioral seizures in response to threshold stimulation. Vehicle-treated kindled rats that were then given topiramate displayed significantly attenuated behavioral seizures induced by the threshold stimulation. Topiramate exhibited age-dependent disease-modifying effects under conditions of rapid kindling, but failed to block epileptogenesis. Topiramate also inhibited kindled seizures with equal efficacy across the three ages.

Age-Dependent Effects of Topiramate on the Acquisition and the Retention of Rapid Kindling

PubMed Central

Mazarati, Andréy; Shin, Don; Auvin, Stéphane; Sankar, Raman

2008-01-01

Summary Purpose To examine antiepileptogenic, disease-modifying, and anticonvulsant effects of topiramate under conditions of rapid kindling at different stages of development. Methods Afterdischarge threshold (ADT) and duration (ADD) were examined in two-, three-, and five-week old Wistar rats before and after administration of topiramate (200 mg/kg). Animals underwent a rapid kindling protocol (sixty 10 second trains, bipolar 20 Hz square wave pulses delivered every five minutes). The progression of behavioral and electrographic seizures, and responses to test stimulations 24 hours after the protocol were compared between topiramate and vehicle treated control rats. In addition, rats that were previously given vehicle only prior to kindling, were then given topiramate to examine the effect on established kindled seizures. Results In two-week old animals, topiramate affected neither the baseline afterdischarge, nor the progression of kindled seizures. In three-week old rats, topiramate did not modify the baseline afterdischarge, but significantly delayed the occurrence of full motor seizures in response to repeated stimulations. Topiramate treatment of five-week old rats increased baseline ADT, shortened ADD, and delayed the progression of kindled seizures. Twenty four hours after the last kindling stimulation, animals of all ages exhibited a decreased ADT, an increase ADD, and developed behavioral seizures in response to threshold stimulation. Vehicle treated kindled rats that were then given topiramate displayed significantly attenuated behavioral seizures induced by the threshold stimulation. Conclusions Topiramate exhibited age-dependent disease-modifying effects under conditions of rapid kindling, but failed to block epileptogenesis. Topiramate also inhibited kindled seizures with equal efficacy across the three ages. PMID:17319916

5-HT modulation of pain perception in humans.

PubMed

Martin, Sarah L; Power, Andrea; Boyle, Yvonne; Anderson, Ian M; Silverdale, Monty A; Jones, Anthony K P

2017-10-01

Although there is clear evidence for the serotonergic regulation of descending control of pain in animals, little direct evidence exists in humans. The majority of our knowledge comes from the use of serotonin (5-HT)-modulating antidepressants as analgesics in the clinical management of chronic pain. Here, we have used an acute tryptophan depletion (ATD) to manipulate 5-HT function and examine its effects of ATD on heat pain threshold and tolerance, attentional manipulation of nociceptive processing and mood in human volunteers. Fifteen healthy participants received both ATD and balanced amino acid (BAL) drinks on two separate sessions in a double-blind cross-over design. Pain threshold and tolerance were determined 4 h post-drink via a heat thermode. Additional attention, distraction and temperature discrimination paradigms were completed using a laser-induced heat pain stimulus. Mood was assessed prior and throughout each session. Our investigation reported that the ATD lowered plasma TRP levels by 65.05 ± 7.29% and significantly reduced pain threshold and tolerance in response to the heat thermode. There was a direct correlation between the reduction in total plasma TRP levels and reduction in thermode temperature. In contrast, ATD showed no effect on laser-induced pain nor significant impact of the distraction-induced analgesia on pain perception but did reduce performance of the painful temperature discrimination task. Importantly, all findings were independent of any effects of ATD on mood. As far as we are aware, it is the first demonstration of 5-HT effects on pain perception which are not confounded by mood changes.

Pain Sensitivity Risk Factors for Chronic TMD: Descriptive Data and Empirically Identified Domains from the OPPERA Case Control Study

PubMed Central

Greenspan, Joel D.; Slade, Gary D.; Bair, Eric; Dubner, Ronald; Fillingim, Roger B.; Ohrbach, Richard; Knott, Charlie; Mulkey, Flora; Rothwell, Rebecca; Maixner, William

2011-01-01

Many studies report that people with temporomandibular disorders (TMD) are more sensitive to experimental pain stimuli than TMD-free controls. Such differences in sensitivity are observed in remote body sites as well as in the orofacial region, suggesting a generalized upregulation of nociceptive processing in TMD cases. This large case-control study of 185 adults with TMD and 1,633 TMD-free controls measured sensitivity to painful pressure, mechanical cutaneous, and heat stimuli, using multiple testing protocols. Based on an unprecedented 36 experimental pain measures, 28 showed statistically significantly greater pain sensitivity in TMD cases than controls. The largest effects were seen for pressure pain thresholds at multiple body sites and cutaneous mechanical pain threshold. The other mechanical cutaneous pain measures and many of the heat pain measures showed significant differences, but with lesser effect sizes. Principal component analysis (PCA) of the pain measures derived from 1,633 controls identified five components labeled: (1) heat pain ratings, (2) heat pain aftersensations and tolerance, (3) mechanical cutaneous pain sensitivity, (4) pressure pain thresholds, and (5) heat pain temporal summation. These results demonstrate that, compared to TMD-free controls, chronic TMD cases are more sensitive to many experimental noxious stimuli at extra-cranial body sites, and provides for the first time the ability to directly compare the case-control effect sizes of a wide range of pain sensitivity measures. PMID:22074753

Noise-induced hearing loss in workers exposed to urban stressors.

PubMed

Caciari, Tiziana; Rosati, Maria Valeria; Casale, Teodorico; Loreti, Beatrice; Sancini, Angela; Riservato, Roberto; Nieto, Hector A; Frati, Paola; Tomei, Francesco; Tomei, Gianfranco

2013-10-01

The technological and industrial progress together with the intensification of vehicular traffic and the adoption of new social habits are the cause of an increasing noise pollution with possible negative effects on the auditory system. This study aims to assess the noise exposure levels and the effects on the hearing threshold in outdoor and indoor male workers of a big Italian city. The study was carried out on 357 outdoor male workers, exposed to urban noise and on a control group of 357 unexposed indoor workers. Noise levels were measured in 30 outdoor and indoor areas. The subjects underwent tonal liminal audiometry in order to determine the value of their hearing threshold. During their working activity, outdoor and indoor workers are exposed to different noise levels LEX<80 dB(A). At mid-low frequencies (250-2000 Hz), the results show significant differences in the average values of hearing threshold between the two groups in both ears and for all age classes; there are no significant differences between the two groups at higher frequencies. The outdoor noise levels measured are not usually ototoxic and the hearing loss at mid-low frequencies is not characteristic of the exposure to industrial noise. For these reasons the Authors hypothesize that the results may be due to the combined effect of the exposure to noise and to ototoxic air pollutants. The impairment of speech frequencies is disabling and involves the risk of missed forensic recognition. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of exercise training on HbA1c and VO2peak in patients with type 2 diabetes and coronary artery disease: A randomised clinical trial.

PubMed

Byrkjeland, Rune; Njerve, Ida U; Anderssen, Sigmund; Arnesen, Harald; Seljeflot, Ingebjørg; Solheim, Svein

2015-09-01

Few exercise trials have focused on patients with both type 2 diabetes and coronary artery disease. We investigated the effects of 1 year of exercise training on HbA1c and VO(2peak) in these patients. Patients with type 2 diabetes and coronary artery disease (n = 137) were randomised to combined exercise training or control group. HbA(1c) was measured at the beginning and end of the study. Changes in VO(2peak), and also ventilatory threshold and time to exhaustion, were assessed by cardiopulmonary exercise testing. No differences in changes between the randomised groups were observed in HbA1c and VO(2peak), whereas ventilatory threshold and time to exhaustion increased significantly in the exercise group compared with the controls (p = 0.046 and p = 0.034). In patients without previous acute myocardial infarction and diabetes microvascular complications (n = 46), the exercise group did improve HbA1c and VO(2peak) compared with the controls (p = 0.052 and p = 0.035). No significant effects of exercise training on HbA(1c) or VO(2peak) were observed in patients with type 2 diabetes and coronary artery disease, although improvements were seen in patients without vascular complications beyond coronary artery disease, implying that the degree of vascular disease may influence exercise responses. Ventilatory threshold and time to exhaustion did increase significantly, indicating improved exercise performance despite the minor change in VO(2peak). © The Author(s) 2015.

Therapeutic effect of adeno-associated virus (AAV)-mediated ADNF-9 expression on cochlea of kanamycin-deafened guinea pigs.

PubMed

Zheng, Guoxi; Zhu, Zhu; Zhu, Kang; Wei, Junrong; Jing, Yang; Duan, Maoli

2013-10-01

rAAV-NT4-ADNF-9 could ameliorate the damage to auditory function and repair previous impairment of cochlear hair cell loss induced by kanamycin. To investigate the therapeutic effect of ADNF-9 on cochlear hair cells using the recombinant adeno-associated virus (AAV) carrying fusion gene NT4-ADNF-9 and the kanamycin-deafened guinea pig model. Forty white guinea pigs with normal auricle reflex and normal auditory brainstem responses (ABRs) were randomly divided into four groups. Kanamycin was administered to the animals in groups A, B, and C to establish the deafened guinea pig model. rAAV-NT4-ADNF-9, vector only, and artificial perilymph were then delivered to the cochlear tissue of animals in groups A, B, and C, respectively, through the round window membrane. Animals in group D did not receive any treatment and acted as normal controls. The hearing thresholds on the surgery side were recorded before and after the transfection treatment. Fourteen days after treatment, cochleae were removed for paraffin slide preparation and cochlear surface preparation. A phase contrast microscope was used to observe the protective effect of ADNF-9 on hair cells. Significant reduction of the ABR threshold was observed after rAAV-NT4-ADNF-9 treatment (p < 0.05). After 14 days of treatment, the ABR threshold was also significantly different between the rAAV-NT4-ADNF-9-infected group and the non-infected group. Moreover, phase contrast microscopy showed significantly less hair cell damage or hair cell loss in the group treated with rAAV-NT4-ADNF-9 than in the groups treated with vector only or artificial perilymph (p < 0.05).

Could edaravone prevent gentamicin ototoxicity? An experimental study.

PubMed

Turan, M; Ciğer, E; Arslanoğlu, S; Börekci, H; Önal, K

2017-02-01

Clinical application of gentamicin may cause nephrotoxicity and ototoxicity. Our study is the first study to investigate the protective effects of edaravone against the gentamicin-induced ototoxicity. We investigated the protective effect of intraperitoneal (i.p.) edaravone application against gentamicin-induced ototoxicity in guinea pigs. Fourteen guinea pigs were divided into two equal groups consisting of a control group and a study group. One-hundred sixty milligrams per kilogram subcutaneous gentamicin and 0.3 mL i.p. saline were applied simultaneously once daily to seven guinea pigs in the control group (group 1). One-hundred sixty milligrams per kilogram gentamicin was applied subcutaneously and 3 mg/kg edaravone was applied intraperitoneally once daily for 7 days simultaneously to seven guinea pigs in the study group (group 2). Following the drug application, auditory brainstem response measurements were performed for the left ear on the 3rd and 7th days. Hearing threshold values of the group 1 and group 2 measured in the 3rd day of the study were detected as 57.14 ± 4.88 and 82.86 ± 7.56, respectively. This difference was statistically significant ( p < 0.05). Hearing threshold values of the group 1 and group 2 measured in the 7th day of the study were detected as 87.14 ± 4.88 and 62.86 ± 4.88, respectively. This difference was statistically significant ( p < 0.05). A statistically significant difference between the average threshold values of edaravone-administered group 2 and that of group 1 without edaravone was found. These differences show that systemic edaravone administration could diminish ototoxic effects of gentamicin and the severity of the hearing loss.

MiR-137-derived polygenic risk: effects on cognitive performance in patients with schizophrenia and controls.

PubMed

Cosgrove, D; Harold, D; Mothersill, O; Anney, R; Hill, M J; Bray, N J; Blokland, G; Petryshen, T; Richards, A; Mantripragada, K; Owen, M; O'Donovan, M C; Gill, M; Corvin, A; Morris, D W; Donohoe, G

2017-01-24

Variants at microRNA-137 (MIR137), one of the most strongly associated schizophrenia risk loci identified to date, have been associated with poorer cognitive performance. As microRNA-137 is known to regulate the expression of ~1900 other genes, including several that are independently associated with schizophrenia, we tested whether this gene set was also associated with variation in cognitive performance. Our analysis was based on an empirically derived list of genes whose expression was altered by manipulation of MIR137 expression. This list was cross-referenced with genome-wide schizophrenia association data to construct individual polygenic scores. We then tested, in a sample of 808 patients and 192 controls, whether these risk scores were associated with altered performance on cognitive functions known to be affected in schizophrenia. A subgroup of healthy participants also underwent functional imaging during memory (n=108) and face processing tasks (n=83). Increased polygenic risk within the empirically derived miR-137 regulated gene score was associated with significantly lower performance on intelligence quotient, working memory and episodic memory. These effects were observed most clearly at a polygenic threshold of P=0.05, although significant results were observed at all three thresholds analyzed. This association was found independently for the gene set as a whole, excluding the schizophrenia-associated MIR137 SNP itself. Analysis of the spatial working memory fMRI task further suggested that increased risk score (thresholded at P=10 -5 ) was significantly associated with increased activation of the right inferior occipital gyrus. In conclusion, these data are consistent with emerging evidence that MIR137 associated risk for schizophrenia may relate to its broader downstream genetic effects.

[Site of prelingual cochlear stimulation and its effect on electrically evoked compound action potentials and refractory using the Nucleus 24 standard].

PubMed

Ma, R Y; Li, W; Jiang, X J

2016-12-01

Objective: To investigate the correlation between the site of prelingual cochlear stimulation and its effect on electrically evoked compound action potentials. Method: Recordings of auditory nerve responses were conducted in 32 prelingual subjects to demonstrate the feasibility of ECAP recordings using the nerve response telemetry(NRT) feature of the Nucleus CI24R(CA) system software. These recordings were then analyzed based on the site of cochlear stimulation defined as basal, middle and apical to determine if the amplitude, threshold and slope of the amplitude growth function and the refractory time differs depending on the region of stimulation. Result: Findings of our prelingual children showed significant differences in the ECAP recordings depending on the stimulation site. Comparing the apical with the basal region, on average higher amplitudes, lower thresholds and steeper slopes of the amplitude growth function hadbeen observed. The refractory time showed an overall dependence on cochlear region; however post-hoc tests showed no significant effect between individual regions. Conclusion: Obtaining ECAP recordings is also possible in the most apical region of the cochlea. However, differences can be observed depending on the region of the cochlea stimulated. Specifically, significant higher ECAP amplitude, lower thresholds and steeper amplitude growth function slopes have been observed in the apical region. These differences between prelingual children and adults could be explained by the location of the stimulating electrode with respect to the neural tissue in the cochlea, a higher density, or an increased neural survival rate of neural tissue in the apex. Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.

Infantile nystagmus adapts to visual demand.

PubMed

Wiggins, Debbie; Woodhouse, J Margaret; Margrain, Tom H; Harris, Christopher M; Erichsen, Jonathan T

2007-05-01

To determine the effect of visual demand on the nystagmus waveform. Individuals with infantile nystagmus syndrome (INS) commonly report that making an effort to see can intensify their nystagmus and adversely affect vision. However, such an effect has never been confirmed experimentally. The eye movement behavior of 11 subjects with INS were recorded at different gaze angles while the subjects viewed visual targets under two conditions: above and then at resolution threshold. Eye movements were recorded by infrared oculography and visual acuity (VA) was measured using Landolt C targets and a two-alternative, forced-choice (2AFC) staircase procedure. Eye movement data were analyzed at the null zone for changes in amplitude, frequency, intensity, and foveation characteristics. Waveform type was also noted under the two conditions. Data from 11 subjects revealed a significant reduction in nystagmus amplitude (P < 0.05), frequency (P < 0.05), and intensity (P < 0.01) when target size was at visual threshold. The percentage of time the eye spent within the low-velocity window (i.e., foveation) significantly increased when target size was at visual threshold (P < 0.05). Furthermore, a change in waveform type with increased visual demand was exhibited by two subjects. The results indicate that increased visual demand modifies the nystagmus waveform favorably (and possibly adaptively), producing a significant reduction in nystagmus intensity and prolonged foveation. These findings contradict previous anecdotal reports that visual effort intensifies the nystagmus eye movement at the cost of visual performance. This discrepancy may be attributable to the lack of psychological stress involved in the visual task reported here. This is consistent with the suggestion that it is the visual importance of the task to the individual rather than visual demand per se which exacerbates INS. Further studies are needed to investigate quantitatively the effects of stress and psychological factors on INS waveforms.

Projected loss of a salamander diversity hotspot as a consequence of projected global climate change.

PubMed

Milanovich, Joseph R; Peterman, William E; Nibbelink, Nathan P; Maerz, John C

2010-08-16

Significant shifts in climate are considered a threat to plants and animals with significant physiological limitations and limited dispersal abilities. The southern Appalachian Mountains are a global hotspot for plethodontid salamander diversity. Plethodontids are lungless ectotherms, so their ecology is strongly governed by temperature and precipitation. Many plethodontid species in southern Appalachia exist in high elevation habitats that may be at or near their thermal maxima, and may also have limited dispersal abilities across warmer valley bottoms. We used a maximum-entropy approach (program Maxent) to model the suitable climatic habitat of 41 plethodontid salamander species inhabiting the Appalachian Highlands region (33 individual species and eight species included within two species complexes). We evaluated the relative change in suitable climatic habitat for these species in the Appalachian Highlands from the current climate to the years 2020, 2050, and 2080, using both the HADCM3 and the CGCM3 models, each under low and high CO(2) scenarios, and using two-model thresholds levels (relative suitability thresholds for determining suitable/unsuitable range), for a total of 8 scenarios per species. While models differed slightly, every scenario projected significant declines in suitable habitat within the Appalachian Highlands as early as 2020. Species with more southern ranges and with smaller ranges had larger projected habitat loss. Despite significant differences in projected precipitation changes to the region, projections did not differ significantly between global circulation models. CO(2) emissions scenario and model threshold had small effects on projected habitat loss by 2020, but did not affect longer-term projections. Results of this study indicate that choice of model threshold and CO(2) emissions scenario affect short-term projected shifts in climatic distributions of species; however, these factors and choice of global circulation model have relatively small affects on what is significant projected loss of habitat for many salamander species that currently occupy the Appalachian Highlands.

Noise induced hearing loss risk assessment in truck drivers.

PubMed

Karimi, Ali; Nasiri, Saleh; Kazerooni, Farshid Khodaparast; Oliaei, Mohammad

2010-01-01

Hearing sense is one of the key elements which may have impact on the driver's task quality. This cross-sectional study investigates the hearing status of 500 truck drivers by pure tone audiometry (AC) in one of the cities in Fars province, Iran. Hearing threshold levels of the subjects were measured in frequencies of 500Hz-8000Hz. Screening and determination of permanent threshold shift (PTS) was the first aim of this study. Hence tests were done at least 16 hours after any exposure to noticeable sound. The effect of age as a confounding factor was considered using ISO equation and subtracted from whole hearing threshold. The threshold of 25 dB HL and above was considered abnormal but the calculation of hearing was also carried out using 0 dB HL as reference. Subjects were categorized into two groups on the basis of working experience and the hearing threshold of 25 dB was considered a boundary of normal hearing sense. The results of Pearson Chi-Square test showed that working experience as an independent variable has significant contributing effect on hearing thresholds of truck drivers in frequencies of 500, 1000, 2000 and 4000 Hz (p greater than 0.05). Also, it was shown that currently nine and 12.6 % of truck drivers suffer from impaired hearing sense in left and right respectively (hearing threshold level greater than 25 dB) in mid frequencies (500, 1000, 2000 Hz) and 45% in high frequencies of both ears (4000 and 8000 Hz). The results indicated that hearing damage of professional drivers was expected to occur sooner at 4000 and 8000 Hz than lower frequencies. Finally it was deduced that the occupational conditions of truck drivers may have bilateral, symmetrical harmful effect on hearing threshold sense in all frequencies mainly in frequency of 4000 Hz, so health surveillance programs such as education and periodic medical examinations are emphasized for pre-diagnosing and prevention of any possible impairment and an urgent need to take up some interventions such as better maintenance of roads, automobile industry efforts to reduce the noise level emission of vehicles and reducing number of working hours per day of drivers are highlighted to improve the harmful working conditions of truck drivers.

Chromatic Perceptual Learning but No Category Effects without Linguistic Input

PubMed Central

Grandison, Alexandra; Sowden, Paul T.; Drivonikou, Vicky G.; Notman, Leslie A.; Alexander, Iona; Davies, Ian R. L.

2016-01-01

Perceptual learning involves an improvement in perceptual judgment with practice, which is often specific to stimulus or task factors. Perceptual learning has been shown on a range of visual tasks but very little research has explored chromatic perceptual learning. Here, we use two low level perceptual threshold tasks and a supra-threshold target detection task to assess chromatic perceptual learning and category effects. Experiment 1 investigates whether chromatic thresholds reduce as a result of training and at what level of analysis learning effects occur. Experiment 2 explores the effect of category training on chromatic thresholds, whether training of this nature is category specific and whether it can induce categorical responding. Experiment 3 investigates the effect of category training on a higher level, lateralized target detection task, previously found to be sensitive to category effects. The findings indicate that performance on a perceptual threshold task improves following training but improvements do not transfer across retinal location or hue. Therefore, chromatic perceptual learning is category specific and can occur at relatively early stages of visual analysis. Additionally, category training does not induce category effects on a low level perceptual threshold task, as indicated by comparable discrimination thresholds at the newly learned hue boundary and adjacent test points. However, category training does induce emerging category effects on a supra-threshold target detection task. Whilst chromatic perceptual learning is possible, learnt category effects appear to be a product of left hemisphere processing, and may require the input of higher level linguistic coding processes in order to manifest. PMID:27252669

[Comparison of tone burst evoked auditory brainstem responses with different filter settings for referral infants after hearing screening].

PubMed

Diao, Wen-wen; Ni, Dao-feng; Li, Feng-rong; Shang, Ying-ying

2011-03-01

Auditory brainstem responses (ABR) evoked by tone burst is an important method of hearing assessment in referral infants after hearing screening. The present study was to compare the thresholds of tone burst ABR with filter settings of 30 - 1500 Hz and 30 - 3000 Hz at each frequency, figure out the characteristics of ABR thresholds with the two filter settings and the effect of the waveform judgement, so as to select a more optimal frequency specific ABR test parameter. Thresholds with filter settings of 30 - 1500 Hz and 30 - 3000 Hz in children aged 2 - 33 months were recorded by click, tone burst ABR. A total of 18 patients (8 male/10 female), 22 ears were included. The thresholds of tone burst ABR with filter settings of 30 - 3000 Hz were higher than that with filter settings of 30 - 1500 Hz. Significant difference was detected for that at 0.5 kHz and 2.0 kHz (t values were 2.238 and 2.217, P < 0.05), no significant difference between the two filter settings was detected at the rest frequencies tone evoked ABR thresholds. The waveform of ABR with filter settings of 30 - 1500 Hz was smoother than that with filter settings of 30 - 3000 Hz at the same stimulus intensity. Response curve of the latter appeared jagged small interfering wave. The filter setting of 30 - 1500 Hz may be a more optimal parameter of frequency specific ABR to improve the accuracy of frequency specificity ABR for infants' hearing assessment.

Acupuncture-induced changes of pressure pain threshold are mediated by segmental inhibition--a randomized controlled trial.

PubMed

Baeumler, Petra I; Fleckenstein, Johannes; Benedikt, Franziska; Bader, Julia; Irnich, Dominik

2015-11-01

Our aim was to distinguish between spinal and supraspinal mechanisms in the intact nervous system by comparing homosegmental and heterosegmental effects of electroacupuncture (EA) and manual acupuncture (MA) on sensory perception in healthy volunteers by means of quantitative sensory testing. Seventy-two healthy volunteers were randomly assigned to receive either MA or EA at SP 6, SP 9, GB 39, and ST 36 at the left leg or relaxed for 30 minutes (control group [CG]). Blinded examiners assessed 13 sensory modalities (thermal and mechanical detection and pain thresholds) at the upper arms and lower legs before and after intervention by means of a standardized quantitative sensory testing battery. Change scores of all 13 sensory thresholds were compared between groups. The main outcome measure was the change score of the pressure pain threshold (PPT). There were no baseline differences between groups. Pressure pain threshold change scores at the lower left leg, in the same segment as the needling site, differed significantly (P = 0.008) between the EA (median: 103.01 kPa) and CG groups (median: 0.00 kPa) but not between the MA (median: 0.00 kPa) and CG groups. No further significant change score differences were found between one of the acupuncture groups and the CG. The PPT can be changed by EA. The PPT increase was confined to the segment of needling, which indicates that it is mainly mediated by segmental inhibition in the spinal cord. This underscores the importance of segmental needling and electrical stimulation in clinical practice.

The effect of instantaneous input dynamic range setting on the speech perception of children with the nucleus 24 implant.

PubMed

Davidson, Lisa S; Skinner, Margaret W; Holstad, Beth A; Fears, Beverly T; Richter, Marie K; Matusofsky, Margaret; Brenner, Christine; Holden, Timothy; Birath, Amy; Kettel, Jerrica L; Scollie, Susan

2009-06-01

The purpose of this study was to examine the effects of a wider instantaneous input dynamic range (IIDR) setting on speech perception and comfort in quiet and noise for children wearing the Nucleus 24 implant system and the Freedom speech processor. In addition, children's ability to understand soft and conversational level speech in relation to aided sound-field thresholds was examined. Thirty children (age, 7 to 17 years) with the Nucleus 24 cochlear implant system and the Freedom speech processor with two different IIDR settings (30 versus 40 dB) were tested on the Consonant Nucleus Consonant (CNC) word test at 50 and 60 dB SPL, the Bamford-Kowal-Bench Speech in Noise Test, and a loudness rating task for four-talker speech noise. Aided thresholds for frequency-modulated tones, narrowband noise, and recorded Ling sounds were obtained with the two IIDRs and examined in relation to CNC scores at 50 dB SPL. Speech Intelligibility Indices were calculated using the long-term average speech spectrum of the CNC words at 50 dB SPL measured at each test site and aided thresholds. Group mean CNC scores at 50 dB SPL with the 40 IIDR were significantly higher (p < 0.001) than with the 30 IIDR. Group mean CNC scores at 60 dB SPL, loudness ratings, and the signal to noise ratios-50 for Bamford-Kowal-Bench Speech in Noise Test were not significantly different for the two IIDRs. Significantly improved aided thresholds at 250 to 6000 Hz as well as higher Speech Intelligibility Indices afforded improved audibility for speech presented at soft levels (50 dB SPL). These results indicate that an increased IIDR provides improved word recognition for soft levels of speech without compromising comfort of higher levels of speech sounds or sentence recognition in noise.

Mrz 2/579, a fast kinetic NMDA channel blocker, reduces the development of morphine tolerance in awake rats.

PubMed

Houghton, A K; Parsons, C G; Headley, P M

2001-04-01

The purpose of the present study was to investigate whether uncompetitive NMDA antagonists with fast channel blocking kinetics, which show fewer side effects in man than compounds such as ketamine, affect the development of tolerance to continuous exposure to morphine. Rats were trained on the Randall--Selitto apparatus before being implanted, under halothane anaesthesia, with primed mini-osmotic pumps (240 microl/day). Six rats were implanted with a vehicle filled pump, seven with a morphine filled pump (28.8 mg/kg/day), and eight with a pair of pumps, one containing morphine and the other Mrz 2/579, a new NMDA antagonist (40 mg/kg/day). A fourth group was implanted with a morphine filled pump followed 25 h later by a Mrz 2/579 filled pump. Paw withdrawal tests were undertaken immediately before, and at 2, 4, 6, 8, 10, 12, 24, 48 and 72 h after the first pump was implanted. Before pump implantation, withdrawal thresholds were 120+/-7 g (mean+/-SEM, n=30). Vehicle infusion had no effect on withdrawal thresholds, whereas morphine infusion increased them significantly at 2 and 4 h after pump implantation (+2 h: 208+/-14 g; P<0.001 vs. control). From 6 h the antinociception elicited by morphine declined progressively; at 10 h withdrawal thresholds were significantly lower than the 2 h post-treatment value (P<0.001). In rats treated with morphine plus Mrz 2/579, thresholds remained significantly higher between 10--72 h post-implantation than with morphine alone (P<0.05). In contrast, infusion of the same level of Mrz 2/579 once tolerance had developed did not reverse tolerance. These results indicate that fast NMDA channel blockers such as Mrz 2/579 may prove to be useful in enhancing analgesia to continuous morphine administration.

Effects of serum zinc level on tinnitus.

PubMed

Berkiten, Güler; Kumral, Tolgar Lütfi; Yıldırım, Güven; Salturk, Ziya; Uyar, Yavuz; Atar, Yavuz

2015-01-01

The aim of this study was to assess zinc levels in tinnitus patients, and to evaluate the effects of zinc deficiency on tinnitus and hearing loss. One-hundred patients, who presented to an outpatient clinic with tinnitus between June 2009 and 2014, were included in the study. Patients were divided into three groups according to age: Group I (patients between 18 and 30years of age); Group II (patients between 31 and 60years of age); and Group III (patients between 61 and 78years of age). Following a complete ear, nose and throat examination, serum zinc levels were measured and the severity of tinnitus was quantified using the Tinnitus Severity Index Questionnaire (TSIQ). Patients were subsequently asked to provide a subjective judgment regarding the loudness of their tinnitus. The hearing status of patients was evaluated by audiometry and high-frequency audiometry. An average hearing sensitivity was calculated as the mean value of hearing thresholds between 250 and 20,000Hz. Serum zinc levels between 70 and 120μg/dl were considered normal. The severity and loudness of tinnitus, and the hearing thresholds of the normal zinc level and zinc-deficient groups, were compared. Twelve of 100 (12%) patients exhibited low zinc levels. The mean age of the zinc-deficient group was 65.41±12.77years. Serum zinc levels were significantly lower in group III (p<0.01). The severity and loudness of tinnitus were greater in zinc-deficient patients (p=0.011 and p=0.015, respectively). Moreover, the mean thresholds of air conduction were significantly higher in zinc-deficient patients (p=0.000). We observed that zinc levels decrease as age increases. In addition, there was a significant correlation between zinc level and the severity and loudness of tinnitus. Zinc deficiency was also associated with impairments in hearing thresholds. Copyright © 2015 Elsevier Inc. All rights reserved.

Saltation threshold on Mars - The effect of interparticle force, surface roughness, and low atmospheric density. [from wind-tunnel experiments

NASA Technical Reports Server (NTRS)

Iversen, J. D.; White, B. R.; Pollack, J. B.; Greeley, R.

1976-01-01

Results are reported for wind-tunnel experiments performed to determine the threshold friction speed of particles with different densities. Experimentally determined threshold speeds are plotted as a function of particle diameter and in terms of threshold parameter vs particle friction Reynolds number. The curves are compared with those of previous experiments, and an A-B curve is plotted to show differences in threshold speed due to differences in size distributions and particle shapes. Effects of particle diameter are investigated, an expression for threshold speed is derived by considering the equilibrium forces acting on a single particle, and other approximately valid expressions are evaluated. It is shown that the assumption of universality of the A-B curve is in error at very low pressures for small particles and that only predictions which take account of both Reynolds number and effects of interparticle forces yield reasonable agreement with experimental data. Effects of nonerodible surface roughness are examined, and threshold speeds computed with allowance for this factor are compared with experimental values. Threshold friction speeds on Mars are then estimated for a surface pressure of 5 mbar, taking into account all the factors considered.

Threshold Level and Traceability of Roundup Ready® Soybeans in Tofu Production

PubMed Central

2017-01-01

Summary The aim of this study is to assess DNA degradation, DNA amplification, and GMO quantity during tofu production. Soybean seeds were spiked with Roundup Ready® soybeans (RRS) at 0.9, 2, 3 and 5% (by mass), to assess the level of RSS that would be of practical interest for threshold labelling. Real-time polymerase chain reaction (PCR) was more effective than conventional PCR in the analysis of raw soymilk, okara, boiled soymilk and tofu. The negative effect of grinding and mechanical manipulation was obvious in the okara sample prepared with 3 and 5% RRS, where GMO content was reduced to (2.28±0.23) and (2.74±0.26) %, respectively. However, heating at 100 °C for 10 min did not cause significant degradation of DNA in all samples. The content of RRS in the final product, tofu, was reduced tenfold during processing, ranging from 0.07 to 0.46%, which was below the labelling threshold level. The results are discussed in terms of global harmonization of GMO standards, which could have the positive effect on the trade of lightly processed foodstuffs such as tofu, especially regarding the labelling policies. PMID:29540978

Threshold Level and Traceability of Roundup Ready® Soybeans in Tofu Production.

PubMed

Nikolić, Zorica; Petrović, Gordana; Panković, Dejana; Ignjatov, Maja; Marinković, Dragana; Stojanović, Milan; Đorđević, Vuk

2017-12-01

The aim of this study is to assess DNA degradation, DNA amplification, and GMO quantity during tofu production. Soybean seeds were spiked with Roundup Ready ® soybeans (RRS) at 0.9, 2, 3 and 5% (by mass), to assess the level of RSS that would be of practical interest for threshold labelling. Real-time polymerase chain reaction (PCR) was more effective than conventional PCR in the analysis of raw soymilk, okara, boiled soymilk and tofu. The negative effect of grinding and mechanical manipulation was obvious in the okara sample prepared with 3 and 5% RRS, where GMO content was reduced to (2.28±0.23) and (2.74±0.26) %, respectively. However, heating at 100 °C for 10 min did not cause significant degradation of DNA in all samples. The content of RRS in the final product, tofu, was reduced tenfold during processing, ranging from 0.07 to 0.46%, which was below the labelling threshold level. The results are discussed in terms of global harmonization of GMO standards, which could have the positive effect on the trade of lightly processed foodstuffs such as tofu, especially regarding the labelling policies.

Selective modulation of intracortical inhibition by low-intensity Theta Burst Stimulation.

PubMed

McAllister, S M; Rothwell, J C; Ridding, M C

2009-04-01

Theta Burst Stimulation (TBS) is a repetitive transcranial magnetic stimulation paradigm which has effects on both excitatory and inhibitory intracortical pathways when applied at an intensity of 80% of active motor threshold. As intracortical inhibitory pathways have a lower threshold for activation than excitatory pathways, we sought to determine whether it was possible to selectively target cortical inhibitory circuitry by reducing the intensity of TBS to 70% of active motor threshold. Motor evoked potentials (MEPs), short latency intracortical facilitation (SICF), intracortical facilitation (ICF) and short interval intracortical inhibition (SICI) were measured at baseline, 5-20 and 20-35 min following continuous (cTBS) and intermittent (iTBS) low-intensity TBS in nine healthy subjects. Low-intensity cTBS significantly reduced SICI 5-20 min following stimulation, whilst having no effect on MEPs, SICF or ICF. Low-intensity iTBS had no effect on SICI, MEPs, SICF or ICF. It is possible to selectively target intracortical inhibitory networks for modulation by low-intensity TBS, however, responses may critically depend upon the particular paradigm chosen. These findings have important implications for the treatment of neurological disorders where abnormal levels of intracortical inhibition are present, such as Parkinson's disease and focal hand dystonia and requires further investigation.

Surface damage of thin AlN films with increased oxygen content by nanosecond and femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Gruzdev, Vitaly; Salakhutdinov, Ildar; Chen, J. K.; Danylyuk, Yuriy; McCullen, Erik; Auner, Gregory

2009-10-01

AlN films deposited on sapphire substrates were damaged by single UV nanosecond (at 248 nm) and IR femtosecond (at 775 nm) laser pulses in air at normal pressure. The films had high (27-35 atomic %) concentration of oxygen introduced into thin surface layer (5-10 nm thickness). We measured damage threshold and studied morphology of the damage sites with atomic force and Nomarski optical microscopes with the objective to determine a correlation between damage processes and oxygen content. The damage produced by nanosecond pulses was accompanied by significant thermal effects with evident signatures of melting, chemical modification of the film surface, and specific redistribution of micro-defect rings around the damage spots. The nanosecond-damage threshold exhibited pronounced increase with increase of the oxygen content. In contrast to that, the femtosecond pulses produced damage without any signs of thermal, thermo-mechanical or chemical effects. No correlation between femtosecond-damage threshold and oxygen content as well as presence of defects within the laser-damage spot was found. We discuss the influence of the oxygen contamination on film properties and related mechanisms responsible for the specific damage effects and morphology of the damage sites observed in the experiments.

Diagnostic Dilemma for Low Viremia with Significant Fibrosis; Is HBV DNA Threshold Level a Good Indicator for Predicting Liver Damage?

PubMed

Yenilmez, Ercan; Çetinkaya, Rıza Aytaç; Tural, Ersin

2018-05-04

The most important difficulties about management of hepatitis B are still determining the liver damage and the right time to start antiviral therapy. To reveal the role of hepatitis B virus DNA threshold level for prediction of liver fibrosis and inflammation in young-aged hepatitis B e antigen negative chronic hepatitis B patients. Diagnostic accuracy study. A total of 273 hepatitis B e antigen negative young chronic hepatitis B patients with any hepatitis B virus DNA levels between 2008 and 2016, who had liver biopsy after at least 6 months follow up period, enrolled in this retrospective study. We created two groups as case and control, cases with hepatitis B virus DNA levels below 2.000 IU/mL and controls with hepatitis B virus DNA levels over 2.000 IU/mL. Having histological activity index ≥4 or/and fibrosis scores ≥2 were defined as significant histological abnormality. Then, we analyzed the relationship between these groups. We showed that significant fibrosis may occur in one third of young chronic hepatitis B patients with low viremia (30.2%, n=42/139 in cases, %55.2, n=74/134 in controls). Among the 42 cases with low viremia and significant fibrosis, 21.4% had alanine aminotransferase level between 40-59 U/L, 42.8% had alanine aminotransferase level between 60-79 U/L, and 35.7% had alanine aminotransferase level over 80 U/L. There was weak correlation between hepatitis B virus DNA threshold level and fibrosis score (p=0.000, rho=0.253). The optimum serum hepatitis B virus DNA threshold level in our study for predicting significant fibrosis was 1293 IU/mL (p=0.00, AUC: 0.657±0.034). The optimum alanine aminotransferase threshold level for predicting significant histological activity index and fibrosis was 64.5 and 59.5 U/L, respectively. The sensitivity and the specificity of 1293 vs 2000 IU/mL hepatitis B virus DNA threshold with 60 U/L alanine aminotransferase threshold level for predicting F≥2 fibrosis score were similar (sensitivity: 0.43 and 0.38, respectively; specificity: 0.76 and 0.77, respectively). Significant fibrosis may occur even in young cases with low viremia. It is not possible to define a single threshold hepatitis B virus DNA level for differentiating inactive carriers from patients with hepatitis B e antigen-negative chronic hepatitis. Diagnostic accuracy of hepatitis B virus DNA with alanine aminotransferase thresholds for the prediction of significant fibrosis is weak.

Selective serotonin reuptake inhibitors versus placebo in patients with major depressive disorder. A systematic review with meta-analysis and Trial Sequential Analysis.

PubMed

Jakobsen, Janus Christian; Katakam, Kiran Kumar; Schou, Anne; Hellmuth, Signe Gade; Stallknecht, Sandra Elkjær; Leth-Møller, Katja; Iversen, Maria; Banke, Marianne Bjørnø; Petersen, Iggiannguaq Juhl; Klingenberg, Sarah Louise; Krogh, Jesper; Ebert, Sebastian Elgaard; Timm, Anne; Lindschou, Jane; Gluud, Christian

2017-02-08

The evidence on selective serotonin reuptake inhibitors (SSRIs) for major depressive disorder is unclear. Our objective was to conduct a systematic review assessing the effects of SSRIs versus placebo, 'active' placebo, or no intervention in adult participants with major depressive disorder. We searched for eligible randomised clinical trials in The Cochrane Library's CENTRAL, PubMed, EMBASE, PsycLIT, PsycINFO, Science Citation Index Expanded, clinical trial registers of Europe and USA, websites of pharmaceutical companies, the U.S. Food and Drug Administration (FDA), and the European Medicines Agency until January 2016. All data were extracted by at least two independent investigators. We used Cochrane systematic review methodology, Trial Sequential Analysis, and calculation of Bayes factor. An eight-step procedure was followed to assess if thresholds for statistical and clinical significance were crossed. Primary outcomes were reduction of depressive symptoms, remission, and adverse events. Secondary outcomes were suicides, suicide attempts, suicide ideation, and quality of life. A total of 131 randomised placebo-controlled trials enrolling a total of 27,422 participants were included. None of the trials used 'active' placebo or no intervention as control intervention. All trials had high risk of bias. SSRIs significantly reduced the Hamilton Depression Rating Scale (HDRS) at end of treatment (mean difference -1.94 HDRS points; 95% CI -2.50 to -1.37; P < 0.00001; 49 trials; Trial Sequential Analysis-adjusted CI -2.70 to -1.18); Bayes factor below predefined threshold (2.01*10 -23 ). The effect estimate, however, was below our predefined threshold for clinical significance of 3 HDRS points. SSRIs significantly decreased the risk of no remission (RR 0.88; 95% CI 0.84 to 0.91; P < 0.00001; 34 trials; Trial Sequential Analysis adjusted CI 0.83 to 0.92); Bayes factor (1426.81) did not confirm the effect). SSRIs significantly increased the risks of serious adverse events (OR 1.37; 95% CI 1.08 to 1.75; P = 0.009; 44 trials; Trial Sequential Analysis-adjusted CI 1.03 to 1.89). This corresponds to 31/1000 SSRI participants will experience a serious adverse event compared with 22/1000 control participants. SSRIs also significantly increased the number of non-serious adverse events. There were almost no data on suicidal behaviour, quality of life, and long-term effects. SSRIs might have statistically significant effects on depressive symptoms, but all trials were at high risk of bias and the clinical significance seems questionable. SSRIs significantly increase the risk of both serious and non-serious adverse events. The potential small beneficial effects seem to be outweighed by harmful effects. PROSPERO CRD42013004420.

On the Estimation of the Cost-Effectiveness Threshold: Why, What, How?

PubMed

Vallejo-Torres, Laura; García-Lorenzo, Borja; Castilla, Iván; Valcárcel-Nazco, Cristina; García-Pérez, Lidia; Linertová, Renata; Polentinos-Castro, Elena; Serrano-Aguilar, Pedro

2016-01-01

Many health care systems claim to incorporate the cost-effectiveness criterion in their investment decisions. Information on the system's willingness to pay per effectiveness unit, normally measured as quality-adjusted life-years (QALYs), however, is not available in most countries. This is partly because of the controversy that remains around the use of a cost-effectiveness threshold, about what the threshold ought to represent, and about the appropriate methodology to arrive at a threshold value. The aim of this article was to identify and critically appraise the conceptual perspectives and methodologies used to date to estimate the cost-effectiveness threshold. We provided an in-depth discussion of different conceptual views and undertook a systematic review of empirical analyses. Identified studies were categorized into the two main conceptual perspectives that argue that the threshold should reflect 1) the value that society places on a QALY and 2) the opportunity cost of investment to the system given budget constraints. These studies showed different underpinning assumptions, strengths, and limitations, which are highlighted and discussed. Furthermore, this review allowed us to compare the cost-effectiveness threshold estimates derived from different types of studies. We found that thresholds based on society's valuation of a QALY are generally larger than thresholds resulting from estimating the opportunity cost to the health care system. This implies that some interventions with positive social net benefits, as informed by individuals' preferences, might not be an appropriate use of resources under fixed budget constraints. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

A comparison of signal detection theory to the objective threshold/strategic model of unconscious perception.

PubMed

Haase, Steven J; Fisk, Gary D

2011-08-01

A key problem in unconscious perception research is ruling out the possibility that weak conscious awareness of stimuli might explain the results. In the present study, signal detection theory was compared with the objective threshold/strategic model as explanations of results for detection and identification sensitivity in a commonly used unconscious perception task. In the task, 64 undergraduate participants detected and identified one of four briefly displayed, visually masked letters. Identification was significantly above baseline (i.e., proportion correct > .25) at the highest detection confidence rating. This result is most consistent with signal detection theory's continuum of sensory states and serves as a possible index of conscious perception. However, there was limited support for the other model in the form of a predicted "looker's inhibition" effect, which produced identification performance that was significantly below baseline. One additional result, an interaction between the target stimulus and type of mask, raised concerns for the generality of unconscious perception effects.

Single bright light exposure decreases sweet taste threshold in healthy volunteers.

PubMed

Srivastava, Shrikant; Donaldson, Lucy F; Rai, Dheeraj; Melichar, Jan K; Potokar, John

2013-10-01

Bright light exposure can alter circulating serotonin levels, and alteration of available serotonin by acute selective serotonin reuptake inhibition significantly lowers sweet but not salt taste recognition thresholds. We tested the hypothesis that bright light exposure would increase sweet but not salt taste sensitivity in healthy adults. Fourteen healthy volunteers were exposed to bright (10,000 lux) and dim (<20 lux) light for 30 min each, in counterbalanced order. Measures of taste perception (salt and sweet) and mood were determined at baseline, and before and after each light exposure period. Recognition thresholds for sucrose were significantly lower after bright but not dim light exposure. Thresholds for salt were unaffected by either condition. There were no significant changes in taste acuity, intensity or pleasantness for both the taste modalities and on visual analogue scales (VASs) for mood, anxiety, sleepiness and alertness, under either light condition. Brief bright light exposure reduces sweet but not salt taste recognition thresholds in healthy humans.

Effect of androgen deprivation therapy on intraprostatic tumour volume identified on 18F choline PET/CT for prostate dose painting radiotherapy.

PubMed

Chan, Joachim; Carver, Antony; Brunt, John N H; Vinjamuri, Sobhan; Syndikus, Isabel

2017-03-01

Prostate dose painting radiotherapy requires the accurate identification of dominant intraprostatic lesions (DILs) to be used as boost volumes; these can be identified on multiparametric MRI (mpMRI) or choline positron emission tomography (PET)/CT. Planning scans are usually performed after 2-3 months of androgen deprivation therapy (ADT). We examine the effect of ADT on choline tracer uptake and boost volumes identified on choline PET/CT. Fluoroethylcholine ( 18 F choline) PET/CT was performed for dose painting radiotherapy planning in patients with intermediate- to high-risk prostate cancer. Initially, they were performed at planning. Owing to low visual tracer uptake, PET/CT for subsequent patients was performed at staging. We compared these two approaches on intraprostatic lesions obtained on PET using both visual and automatic threshold methods [prostate maximum standardized uptake value (SUV max ) 60%] when compared with mpMRI. PET/CT was performed during ADT in 11 patients (median duration of 85 days) and before ADT in 29 patients. ADT significantly reduced overall prostate volume by 17%. During ADT, prostate SUV max was lower although it did not reach statistical significance (4.2 vs 6.6, p = 0.06); three patients had no visually identifiable PET DIL; and visually defined PET DILs were significantly smaller than corresponding mpMRI DILs (p = 0.03). However, all patients scanned before ADT had at least one visually identifiable PET DIL, with no significant size difference between MRI and visually defined PET DILs. In both groups, threshold PET produced larger DILs than visual PET. Both PET methods have moderate sensitivity (0.50-0.68) and high specificity (0.85-0.98) for identifying MRI-defined disease. For visual contouring of boost volumes in prostate dose painting radiotherapy, 18 F choline PET/CT should be performed before ADT. For threshold contouring of boost volumes using our PET/CT scanning protocol, threshold levels of above 60% prostate SUV max may be more suitable. Additional use of PET with MRI for radiotherapy planning can significantly change the overall boost volumes compared with using MRI alone. Advances in knowledge: For prostate dose painting radiotherapy, the additional use of 18 F choline PET with MRI can significantly change the overall boost volumes, and PET should be performed before hormone therapy, especially if boost volumes are visually identified.

The salt-taste threshold in untreated hypertensive patients.

PubMed

Kim, Chang-Yeon; Ye, Mi-Kyung; Lee, Young Soo

2017-01-01

The salt-taste threshold can influence the salt appetite, and is thought to be another marker of sodium intake. Many studies have mentioned the relationship between the sodium intake and blood pressure (BP). The aim of this study was to evaluate the relationship between the salt-taste threshold and urinary sodium excretion in normotensive and hypertensive groups. We analyzed 199 patients (mean age 52 years, male 47.3%) who underwent 24-h ambulatory BP monitoring (ABPM). Hypertension was diagnosed as an average daytime systolic BP of ≥135 mmHg or diastolic BP of ≥85 mmHg by the ABPM. We assessed the salt-taste threshold using graded saline solutions. The salt-taste threshold, 24-h urinary sodium and potassium excretion, and echocardiographic data were compared between the control and hypertensive groups. The detection and recognition threshold of the salt taste did not significantly differ between the control and hypertensive groups. The 24-h urinary sodium excretion of hypertensive patients was significantly higher than that of the control group (140.9 ± 59.8 vs. 117.9 ± 57.2 mEq/day, respectively, p  = 0.011). Also, the urinary sodium-potassium ratio was significantly higher in the hypertensive patients. There was no correlation between the salt-taste threshold and 24-h urinary sodium excretion. The salt-taste threshold might not be related to the BP status as well as the 24-h urinary sodium excretion.

Towards highly stable polymer electronics (Conference Presentation)

NASA Astrophysics Data System (ADS)

Nikolka, Mark; Nasrallah, Iyad; Broch, Katharina; Sadhanala, Aditya; Hurhangee, Michael; McCulloch, Iain; Sirringhaus, Henning

2016-11-01

Due to their ease of processing, organic semiconductors are promising candidates for applications in high performance flexible displays and fast organic electronic circuitry. Recently, a lot of advances have been made on organic semiconductors exhibiting surprisingly high performance and carrier mobilities exceeding those of amorphous silicon. However, there remain significant concerns about their operational and environmental stability, particularly in the context of applications that require a very high level of threshold voltage stability, such as active-matrix addressing of organic light-emitting diode (OLED) displays. Here, we report a novel technique for dramatically improving the operational stress stability, performance and uniformity of high mobility polymer field-effect transistors by the addition of specific small molecule additives to the polymer semiconductor film. We demonstrate for the first time polymer FETs that exhibit stable threshold voltages with threshold voltage shifts of less than 1V when subjected to a constant current operational stress for 1 day under conditions that are representative for applications in OLED active matrix displays. The approach constitutes in our view a technological breakthrough; it also makes the device characteristics independent of the atmosphere in which it is operated, causes a significant reduction in contact resistance and significantly improves device uniformity. We will discuss in detail the microscopic mechanism by which the molecular additives lead to this significant improvement in device performance and stability.

Determine Optimal Stimulus Amplitude for Using Vestibular Stochastic Stimulation to Improve Balance Function

NASA Technical Reports Server (NTRS)

Goel, R.; Kofman, I.; DeDios, Y. E.; Jeevarajan, J.; Stepanyan, V.; Nair, M.; Congdon, S.; Fregia, M.; Cohen, H.; Bloomberg, J.J.;

Modulation frequency discrimination with single and multiple channels in cochlear implant users

PubMed Central

Galvin, John J.; Oba, Sandy; Başkent, Deniz; Fu, Qian-Jie

2015-01-01

Temporal envelope cues convey important speech information for cochlear implant (CI) users. Many studies have explored CI users’ single-channel temporal envelope processing. However, in clinical CI speech processors, temporal envelope information is processed by multiple channels. Previous studies have shown that amplitude modulation frequency discrimination (AMFD) thresholds are better when temporal envelopes are delivered to multiple rather than single channels. In clinical fitting, current levels on single channels must often be reduced to accommodate multi-channel loudness summation. As such, it is unclear whether the multi-channel advantage in AMFD observed in previous studies was due to coherent envelope information distributed across the cochlea or to greater loudness associated with multi-channel stimulation. In this study, single- and multi-channel AMFD thresholds were measured in CI users. Multi-channel component electrodes were either widely or narrowly spaced to vary the degree of overlap between neural populations. The reference amplitude modulation (AM) frequency was 100 Hz, and coherent modulation was applied to all channels. In Experiment 1, single- and multi-channel AMFD thresholds were measured at similar loudness. In this case, current levels on component channels were higher for single- than for multi-channel AM stimuli, and the modulation depth was approximately 100% of the perceptual dynamic range (i.e., between threshold and maximum acceptable loudness). Results showed no significant difference in AMFD thresholds between similarly loud single- and multi-channel modulated stimuli. In Experiment 2, single- and multi-channel AMFD thresholds were compared at substantially different loudness. In this case, current levels on component channels were the same for single-and multi-channel stimuli (“summation-adjusted” current levels) and the same range of modulation (in dB) was applied to the component channels for both single- and multi-channel testing. With the summation-adjusted current levels, loudness was lower with single than with multiple channels and the AM depth resulted in substantial stimulation below single-channel audibility, thereby reducing the perceptual range of AM. Results showed that AMFD thresholds were significantly better with multiple channels than with any of the single component channels. There was no significant effect of the distribution of electrodes on multi-channel AMFD thresholds. The results suggest that increased loudness due to multi-channel summation may contribute to the multi-channel advantage in AMFD, and that that overall loudness may matter more than the distribution of envelope information in the cochlea. PMID:25746914

Statistical approaches for the definition of landslide rainfall thresholds and their uncertainty using rain gauge and satellite data

NASA Astrophysics Data System (ADS)

Rossi, M.; Luciani, S.; Valigi, D.; Kirschbaum, D.; Brunetti, M. T.; Peruccacci, S.; Guzzetti, F.

2017-05-01

Models for forecasting rainfall-induced landslides are mostly based on the identification of empirical rainfall thresholds obtained exploiting rain gauge data. Despite their increased availability, satellite rainfall estimates are scarcely used for this purpose. Satellite data should be useful in ungauged and remote areas, or should provide a significant spatial and temporal reference in gauged areas. In this paper, the analysis of the reliability of rainfall thresholds based on rainfall remote sensed and rain gauge data for the prediction of landslide occurrence is carried out. To date, the estimation of the uncertainty associated with the empirical rainfall thresholds is mostly based on a bootstrap resampling of the rainfall duration and the cumulated event rainfall pairs (D,E) characterizing rainfall events responsible for past failures. This estimation does not consider the measurement uncertainty associated with D and E. In the paper, we propose (i) a new automated procedure to reconstruct ED conditions responsible for the landslide triggering and their uncertainties, and (ii) three new methods to identify rainfall threshold for the possible landslide occurrence, exploiting rain gauge and satellite data. In particular, the proposed methods are based on Least Square (LS), Quantile Regression (QR) and Nonlinear Least Square (NLS) statistical approaches. We applied the new procedure and methods to define empirical rainfall thresholds and their associated uncertainties in the Umbria region (central Italy) using both rain-gauge measurements and satellite estimates. We finally validated the thresholds and tested the effectiveness of the different threshold definition methods with independent landslide information. The NLS method among the others performed better in calculating thresholds in the full range of rainfall durations. We found that the thresholds obtained from satellite data are lower than those obtained from rain gauge measurements. This is in agreement with the literature, where satellite rainfall data underestimate the "ground" rainfall registered by rain gauges.

Statistical Approaches for the Definition of Landslide Rainfall Thresholds and their Uncertainty Using Rain Gauge and Satellite Data

NASA Technical Reports Server (NTRS)

Rossi, M.; Luciani, S.; Valigi, D.; Kirschbaum, D.; Brunetti, M. T.; Peruccacci, S.; Guzzetti, F.

2017-01-01

Models for forecasting rainfall-induced landslides are mostly based on the identification of empirical rainfall thresholds obtained exploiting rain gauge data. Despite their increased availability, satellite rainfall estimates are scarcely used for this purpose. Satellite data should be useful in ungauged and remote areas, or should provide a significant spatial and temporal reference in gauged areas. In this paper, the analysis of the reliability of rainfall thresholds based on rainfall remote sensed and rain gauge data for the prediction of landslide occurrence is carried out. To date, the estimation of the uncertainty associated with the empirical rainfall thresholds is mostly based on a bootstrap resampling of the rainfall duration and the cumulated event rainfall pairs (D,E) characterizing rainfall events responsible for past failures. This estimation does not consider the measurement uncertainty associated with D and E. In the paper, we propose (i) a new automated procedure to reconstruct ED conditions responsible for the landslide triggering and their uncertainties, and (ii) three new methods to identify rainfall threshold for the possible landslide occurrence, exploiting rain gauge and satellite data. In particular, the proposed methods are based on Least Square (LS), Quantile Regression (QR) and Nonlinear Least Square (NLS) statistical approaches. We applied the new procedure and methods to define empirical rainfall thresholds and their associated uncertainties in the Umbria region (central Italy) using both rain-gauge measurements and satellite estimates. We finally validated the thresholds and tested the effectiveness of the different threshold definition methods with independent landslide information. The NLS method among the others performed better in calculating thresholds in the full range of rainfall durations. We found that the thresholds obtained from satellite data are lower than those obtained from rain gauge measurements. This is in agreement with the literature, where satellite rainfall data underestimate the 'ground' rainfall registered by rain gauges.

Temporal clustering of floods in Germany: Do flood-rich and flood-poor periods exist?

NASA Astrophysics Data System (ADS)

Merz, Bruno; Nguyen, Viet Dung; Vorogushyn, Sergiy

2016-10-01

The repeated occurrence of exceptional floods within a few years, such as the Rhine floods in 1993 and 1995 and the Elbe and Danube floods in 2002 and 2013, suggests that floods in Central Europe may be organized in flood-rich and flood-poor periods. This hypothesis is studied by testing the significance of temporal clustering in flood occurrence (peak-over-threshold) time series for 68 catchments across Germany for the period 1932-2005. To assess the robustness of the results, different methods are used: Firstly, the index of dispersion, which quantifies the departure from a homogeneous Poisson process, is investigated. Further, the time-variation of the flood occurrence rate is derived by non-parametric kernel implementation and the significance of clustering is evaluated via parametric and non-parametric tests. Although the methods give consistent overall results, the specific results differ considerably. Hence, we recommend applying different methods when investigating flood clustering. For flood estimation and risk management, it is of relevance to understand whether clustering changes with flood severity and time scale. To this end, clustering is assessed for different thresholds and time scales. It is found that the majority of catchments show temporal clustering at the 5% significance level for low thresholds and time scales of one to a few years. However, clustering decreases substantially with increasing threshold and time scale. We hypothesize that flood clustering in Germany is mainly caused by catchment memory effects along with intra- to inter-annual climate variability, and that decadal climate variability plays a minor role.

An Antiestrogenic Activity Score for tamoxifen and its metabolites is associated with breast cancer outcome

PubMed Central

Alexi, X.; van Werkhoven, E.; Madlensky, L.; Natarajan, L.; Flatt, S. W.; Zwart, W.; Linn, S. C.; Parker, B. A.; Wu, A. H. B.; Pierce, J. P.; Huitema, A. D. R.; Beijnen, J. H.

2018-01-01

Purpose Endoxifen concentrations have been associated with breast cancer recurrence in tamoxifen-treated patients. However, tamoxifen itself and other metabolites also show antiestrogenic anti-tumor activity. Therefore, the aim of this study was to develop a comprehensive Antiestrogenic Activity Score (AAS), which accounts for concentration and antiestrogenic activity of tamoxifen and three metabolites. An association between the AAS and recurrence-free survival was investigated and compared to a previously published threshold for endoxifen concentrations of 5.97 ng/mL. Patients and methods The antiestrogenic activities of tamoxifen, (Z)-endoxifen, (Z)-4-hydroxytamoxifen, and N-desmethyltamoxifen were determined in a cell proliferation assay. The AAS was determined by calculating the sum of each metabolite concentration multiplied by an IC50 ratio, relative to tamoxifen. The AAS was calculated for 1370 patients with estrogen receptor alpha (ERα)-positive breast cancer. An association between AAS and recurrence was investigated using Cox regression and compared with the 5.97 ng/mL endoxifen threshold using concordance indices. Results An AAS threshold of 1798 was associated with recurrence-free survival, hazard ratio (HR) 0.67 (95% confidence interval (CI) 0.47–0.96), bias corrected after bootstrap HR 0.69 (95% CI 0.48–0.99). The concordance indices for AAS and endoxifen did not significantly differ; however, using the AAS threshold instead of endoxifen led to different dose recommendations for 5.2% of the patients. Conclusions Endoxifen concentrations can serve as a proxy for the antiestrogenic effect of tamoxifen and metabolites. However, for the aggregate effect of tamoxifen and three metabolites, defined by an integrative algorithm, a trend towards improving treatment is seen and moreover, is significantly associated with breast cancer recurrence. PMID:28005246

Analgesic effects elicited by neuroactive mediators injected into the ST 36 acupuncture point on inflammatory and neuropathic pain in mice.

PubMed

Vieira, Jadina Santos; Toreti, Jéssica Aline; Carvalho, Ravena Carolina de; de Araújo, João Eduardo; Silva, Marcelo Lourenço; Silva, Josie Resende Torres

2018-05-31

The present study evaluates whether the injection of serotonin, acetylcholine, glutamate, bradykinin, histamine or substance P into the Zusanli (Stomach 36, ST 36) acupoint can also produce the acupuncture-induced antinociceptive effect on inflammatory or neuropathic pain. In this in vivo experimental study a total of 450 male Swiss mice were used. Mice were injected with saline or complete Freund's adjuvant (CFA) or subjected to sham or chronic constriction injury (CCI) surgery. After the establishment of the inflammatory (4 hours) or the neuropathic pain (3 days) the animals (n=6) received manual acupuncture (MA), sham acupuncture (OUT) or injection of saline, serotonin, acetylcholine, glutamate, bradykinin, histamine or substance P into the ST 36 and were evaluated for up to 24 hours. Mechanical threshold was evaluated and the L4-L6 dorsal root ganglion (DRG) was used for analysis of the transient receptor potential vanilloid type 1 (TRPV1) overexpression. The mice from both the CFA or CCI models and treated with MA had significant increases in the thresholds for more than 24 hours. OUT stimulation did not change the thresholds. In the mice injected with each of the mediators, the thresholds were significantly increased for all times in both the CFA and CCI models. TRPV1 overexpression in CFA and CCI mice was reduced at all times by injection of serotonin, acetylcholine or substance P but not by injection of glutamate, histamine or bradykinin. Our data suggests that the neuroactive mediators released by acupuncture-induced tissue injury may contribute to acupuncture-induced analgesia. Copyright © 2018. Published by Elsevier B.V.

Minimum Electric Field Exposure for Seizure Induction with Electroconvulsive Therapy and Magnetic Seizure Therapy.

PubMed

Lee, Won H; Lisanby, Sarah H; Laine, Andrew F; Peterchev, Angel V

2017-05-01

Lowering and individualizing the current amplitude in electroconvulsive therapy (ECT) has been proposed as a means to produce stimulation closer to the neural activation threshold and more focal seizure induction, which could potentially reduce cognitive side effects. However, the effect of current amplitude on the electric field (E-field) in the brain has not been previously linked to the current amplitude threshold for seizure induction. We coupled MRI-based E-field models with amplitude titrations of motor threshold (MT) and seizure threshold (ST) in four nonhuman primates (NHPs) to determine the strength, distribution, and focality of stimulation in the brain for four ECT electrode configurations (bilateral, bifrontal, right-unilateral, and frontomedial) and magnetic seizure therapy (MST) with cap coil on vertex. At the amplitude-titrated ST, the stimulated brain subvolume (23-63%) was significantly less than for conventional ECT with high, fixed current (94-99%). The focality of amplitude-titrated right-unilateral ECT (25%) was comparable to cap coil MST (23%), demonstrating that ECT with a low current amplitude and focal electrode placement can induce seizures with E-field as focal as MST, although these electrode and coil configurations affect differently specific brain regions. Individualizing the current amplitude reduced interindividual variation in the stimulation focality by 40-53% for ECT and 26% for MST, supporting amplitude individualization as a means of dosing especially for ECT. There was an overall significant correlation between the measured amplitude-titrated ST and the prediction of the E-field models, supporting a potential role of these models in dosing of ECT and MST. These findings may guide the development of seizure therapy dosing paradigms with improved risk/benefit ratio.

Effect of hearing aids on auditory function in infants with perinatal brain injury and severe hearing loss.

PubMed

Moreno-Aguirre, Alma Janeth; Santiago-Rodríguez, Efraín; Harmony, Thalía; Fernández-Bouzas, Antonio

2012-01-01

Approximately 2-4% of newborns with perinatal risk factors present with hearing loss. Our aim was to analyze the effect of hearing aid use on auditory function evaluated based on otoacoustic emissions (OAEs), auditory brain responses (ABRs) and auditory steady state responses (ASSRs) in infants with perinatal brain injury and profound hearing loss. A prospective, longitudinal study of auditory function in infants with profound hearing loss. Right side hearing before and after hearing aid use was compared with left side hearing (not stimulated and used as control). All infants were subjected to OAE, ABR and ASSR evaluations before and after hearing aid use. The average ABR threshold decreased from 90.0 to 80.0 dB (p = 0.003) after six months of hearing aid use. In the left ear, which was used as a control, the ABR threshold decreased from 94.6 to 87.6 dB, which was not significant (p>0.05). In addition, the ASSR threshold in the 4000-Hz frequency decreased from 89 dB to 72 dB (p = 0.013) after six months of right ear hearing aid use; the other frequencies in the right ear and all frequencies in the left ear did not show significant differences in any of the measured parameters (p>0.05). OAEs were absent in the baseline test and showed no changes after hearing aid use in the right ear (p>0.05). This study provides evidence that early hearing aid use decreases the hearing threshold in ABR and ASSR assessments with no functional modifications in the auditory receptor, as evaluated by OAEs.

Football match spectator sound exposure and effect on hearing: a pretest-post-test study.

PubMed

Swanepoel, De Wet; Hall, James W

2010-03-30

To determine (i) noise exposure levels of spectators at a FIFA 2010 designated training stadium during a premier soccer league match; and (ii) changes in auditory functioning after the match. This was a one-group pretest-post-test design of football spectators attending a premier soccer league match at a designated FIFA 2010 training stadium in Gauteng, South Africa. Individual spectator noise exposure for the duration of the football match and post-match changes in hearing thresholds were measured with pure-tone audiometry, and cochlear functioning was measured with distortion product oto-acoustic emissions (DPOAEs). The average sound exposure level during the match was 100.5 LAeq (dBA), with peak intensities averaging 140.4 dB(C). A significant (p=0.005) deterioration of post-match hearing thresholds was evident at 2 000 Hz, and post-match DPOAE amplitudes were significantly reduced at 1,266, 3,163 and 5,063 Hz (p=0.011, 0.019, 0.013, respectively). Exposure levels exceeded limits of permissible average and peak sound levels. Significant changes in post-match hearing thresholds and cochlear responsiveness highlight the possible risk for noise-induced hearing loss. Public awareness and personal hearing protection should be prioritized as preventive measures.

Voice Function Differences Following Resting Breathing vs. Submaximal Exercise

PubMed Central

Sandage, Mary J.; Connor, Nadine P.; Pascoe, David D.

2013-01-01

Objectives/Hypothesis There is little known about how physical exercise may alter physiological parameters of voice production. In this investigation, vocal function and upper airway temperature were examined following a bout of submaximal exercise and compared with a resting breathing condition. It was hypothesized that phonation threshold pressure and perceived phonatory effort would increase, and pharyngeal temperature would decrease following an exercise bout. Study Design Using a within-participant repeated measures design, 18 consented participants (9 men, 9 women) completed the study. Methods A 20-minute equilibration task was immediately followed by 8 minutes of submaximal exercise on a stationary bike in a thermally neutral environment (25°C/40% RH). At the end of the equilibration trial and the exercise trial measures were taken in the following order: pharyngeal temperature, phonation threshold pressure, and perceived phonatory effort. Data were analyzed using paired t-tests with significance set at α<0.05. Results Significantly increased phonation threshold pressure and perceived phonatory effort and significantly decreased pharyngeal temperature (1.9°C) were found, supporting the initial hypotheses. Conclusions Findings from this investigation support the widely held belief that voice use associated with physical activity requires additional laryngeal effort and closure forces. The effect of the temperature reduction in the upper airway on voice function requires further study. PMID:23849683

Volume conductor model of transcutaneous electrical stimulation with kilohertz signals

PubMed Central

Medina, Leonel E.; Grill, Warren M.

2014-01-01

Objective Incorporating high-frequency components in transcutaneous electrical stimulation (TES) waveforms may make it possible to stimulate deeper nerve fibers since the impedance of tissue declines with increasing frequency. However, the mechanisms of high-frequency TES remain largely unexplored. We investigated the properties of TES with frequencies beyond those typically used in neural stimulation. Approach We implemented a multilayer volume conductor model including dispersion and capacitive effects, coupled to a cable model of a nerve fiber. We simulated voltage- and current-controlled transcutaneous stimulation, and quantified the effects of frequency on the distribution of potentials and fiber excitation. We also quantified the effects of a novel transdermal amplitude modulated signal (TAMS) consisting of a non-zero offset sinusoidal carrier modulated by a square-pulse train. Main results The model revealed that high-frequency signals generated larger potentials at depth than did low frequencies, but this did not translate into lower stimulation thresholds. Both TAMS and conventional rectangular pulses activated more superficial fibers in addition to the deeper, target fibers, and at no frequency did we observe an inversion of the strength-distance relationship. Current regulated stimulation was more strongly influenced by fiber depth, whereas voltage regulated stimulation was more strongly influenced by skin thickness. Finally, our model reproduced the threshold-frequency relationship of experimentally measured motor thresholds. Significance The model may be used for prediction of motor thresholds in TES, and contributes to the understanding of high-frequency TES. PMID:25380254

A comparative study of xylazine-induced mechanical hypoalgesia in donkeys and horses.

PubMed

Lizarraga, Ignacio; Beths, Thierry

2012-09-01

To compare the effects of xylazine on mechanical nociceptive thresholds in donkeys and horses. Randomized, controlled, crossover, Latin-square, operator-blinded design. Six 3.1 ± 0.89 year old standard donkeys weighing 145.0 ± 30.5 kg and six 9.6 ± 4.4 year old Thoroughbred horses weighing 456.0 ± 69.0 kg. Each animal received one of four doses of xylazine (0.5, 0.7, 0.9, and 1.1 mg kg(-1) ), or acepromazine (0.05 mg kg(-1) ) or saline solution (0.9%) intravenously and mechanical nociceptive thresholds were assessed over 90 minutes. The areas under the threshold change versus time curve values for 60 minutes (AUC(0-60) ) post-drug administration were used to compare the effect of treatment. A 1-week interval was allowed between successive trials on each animal. All doses of xylazine, but not acepromazine or saline, increased mechanical thresholds for up to 60 minutes. Xylazine-induced hypoalgesia was dose-dependent and corresponding AUC(0-60) values for each treatment were not significantly different between donkeys and horses (p ≥ 0.0697). The hypoalgesic effects of xylazine at four different doses were not different between donkeys and horses. Xylazine induced a similar degree of mechanical hypoalgesia in donkeys and horses suggesting that similar doses are needed for both species with regard to analgesia. © 2012 The Authors. Veterinary Anaesthesia and Analgesia. © 2012 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.

Volume conductor model of transcutaneous electrical stimulation with kilohertz signals

NASA Astrophysics Data System (ADS)

Medina, Leonel E.; Grill, Warren M.

2014-12-01

Objective. Incorporating high-frequency components in transcutaneous electrical stimulation (TES) waveforms may make it possible to stimulate deeper nerve fibers since the impedance of tissue declines with increasing frequency. However, the mechanisms of high-frequency TES remain largely unexplored. We investigated the properties of TES with frequencies beyond those typically used in neural stimulation. Approach. We implemented a multilayer volume conductor model including dispersion and capacitive effects, coupled to a cable model of a nerve fiber. We simulated voltage- and current-controlled transcutaneous stimulation, and quantified the effects of frequency on the distribution of potentials and fiber excitation. We also quantified the effects of a novel transdermal amplitude modulated signal (TAMS) consisting of a non-zero offset sinusoidal carrier modulated by a square-pulse train. Main results. The model revealed that high-frequency signals generated larger potentials at depth than did low frequencies, but this did not translate into lower stimulation thresholds. Both TAMS and conventional rectangular pulses activated more superficial fibers in addition to the deeper, target fibers, and at no frequency did we observe an inversion of the strength-distance relationship. Current regulated stimulation was more strongly influenced by fiber depth, whereas voltage regulated stimulation was more strongly influenced by skin thickness. Finally, our model reproduced the threshold-frequency relationship of experimentally measured motor thresholds. Significance. The model may be used for prediction of motor thresholds in TES, and contributes to the understanding of high-frequency TES.

A comparison of the DPSS UV laser ablation characteristic of 1024 and H10F WC-Co

NASA Astrophysics Data System (ADS)

See, Tian Long; Chantzis, Dimitrios; Royer, Raphael; Metsios, Ioannis; Antar, Mohammad; Marimuthu, Sundar

2017-07-01

An investigation on ablation characteristics of 1024 and H10F cobalt cemented tungsten carbide (WC-Co) with a DPSS nanosecond UV laser (50 ns pulse width, 355 nm wavelength, 90 W average power and 10 kHz repetition rate) is presented. The ablation characteristic parameters such as ablation threshold, incubation effect and optical penetration depth were evaluated based on the spot ablation diameter and depth. It was observed that the ablation threshold is significantly influenced by the number of pulses (NOP) and it decreases with increase NOP which is attributed to the incubation effect. Only one ablation region is observed at low laser fluence and an additional molten ablation region is observed at high laser fluence accompanied with cracks. The cracks formation is due to the thermal induced stress and changes in WC microstructure during laser beam irradiation. The crack depth is proportional to the thickness of the molten WC region. The ablation threshold of 1024 WC-Co and H10F WC-Co were found to be Fth1 =4.32 J/cm2 and Fth1 =4.26 J/cm2 respectively. The difference in chemical composition has insignificant effect on the ablation threshold value of the material. The incubation factor and optical penetration depth values of 1024 WC-Co and H10F WC-Co were found to be ξ=0.73, α-1 =411 nm and ξ=0.75, α-1 =397 nm respectively.

Agreeable Smellers and Sensitive Neurotics – Correlations among Personality Traits and Sensory Thresholds

PubMed Central

Croy, Ilona; Springborn, Maria; Lötsch, Jörn; Johnston, Amy N. B.; Hummel, Thomas

2011-01-01

Correlations between personality traits and a wide range of sensory thresholds were examined. Participants (N = 124) completed a personality inventory (NEO-FFI) and underwent assessment of olfactory, trigeminal, tactile and gustatory detection thresholds, as well as examination of trigeminal and tactile pain thresholds. Significantly enhanced odor sensitivity in socially agreeable people, significantly enhanced trigeminal sensitivity in neurotic subjects, and a tendency for enhanced pain tolerance in highly conscientious participants was revealed. It is postulated that varied sensory processing may influence an individual's perception of the environment; particularly their perception of socially relevant or potentially dangerous stimuli and thus, varied with personality. PMID:21556139

Agreeable smellers and sensitive neurotics--correlations among personality traits and sensory thresholds.

PubMed

Croy, Ilona; Springborn, Maria; Lötsch, Jörn; Johnston, Amy N B; Hummel, Thomas

2011-04-27

Correlations between personality traits and a wide range of sensory thresholds were examined. Participants (N = 124) completed a personality inventory (NEO-FFI) and underwent assessment of olfactory, trigeminal, tactile and gustatory detection thresholds, as well as examination of trigeminal and tactile pain thresholds. Significantly enhanced odor sensitivity in socially agreeable people, significantly enhanced trigeminal sensitivity in neurotic subjects, and a tendency for enhanced pain tolerance in highly conscientious participants was revealed. It is postulated that varied sensory processing may influence an individual's perception of the environment; particularly their perception of socially relevant or potentially dangerous stimuli and thus, varied with personality.

Predicting behavioural responses to novel organisms: state-dependent detection theory

PubMed Central

Sih, Andrew

2017-01-01

Human activity alters natural habitats for many species. Understanding variation in animals' behavioural responses to these changing environments is critical. We show how signal detection theory can be used within a wider framework of state-dependent modelling to predict behavioural responses to a major environmental change: novel, exotic species. We allow thresholds for action to be a function of reserves, and demonstrate how optimal thresholds can be calculated. We term this framework ‘state-dependent detection theory’ (SDDT). We focus on behavioural and fitness outcomes when animals continue to use formerly adaptive thresholds following environmental change. In a simple example, we show that exposure to novel animals which appear dangerous—but are actually safe—(e.g. ecotourists) can have catastrophic consequences for ‘prey’ (organisms that respond as if the new organisms are predators), significantly increasing mortality even when the novel species is not predatory. SDDT also reveals that the effect on reproduction can be greater than the effect on lifespan. We investigate factors that influence the effect of novel organisms, and address the potential for behavioural adjustments (via evolution or learning) to recover otherwise reduced fitness. Although effects of environmental change are often difficult to predict, we suggest that SDDT provides a useful route ahead. PMID:28100814

Predicting behavioural responses to novel organisms: state-dependent detection theory.

PubMed

Trimmer, Pete C; Ehlman, Sean M; Sih, Andrew

2017-01-25

Human activity alters natural habitats for many species. Understanding variation in animals' behavioural responses to these changing environments is critical. We show how signal detection theory can be used within a wider framework of state-dependent modelling to predict behavioural responses to a major environmental change: novel, exotic species. We allow thresholds for action to be a function of reserves, and demonstrate how optimal thresholds can be calculated. We term this framework 'state-dependent detection theory' (SDDT). We focus on behavioural and fitness outcomes when animals continue to use formerly adaptive thresholds following environmental change. In a simple example, we show that exposure to novel animals which appear dangerous-but are actually safe-(e.g. ecotourists) can have catastrophic consequences for 'prey' (organisms that respond as if the new organisms are predators), significantly increasing mortality even when the novel species is not predatory. SDDT also reveals that the effect on reproduction can be greater than the effect on lifespan. We investigate factors that influence the effect of novel organisms, and address the potential for behavioural adjustments (via evolution or learning) to recover otherwise reduced fitness. Although effects of environmental change are often difficult to predict, we suggest that SDDT provides a useful route ahead. © 2017 The Author(s).

Unraveling the mechanism of ultraviolet-induced optical gating in Zn1-x Mg x O nanocrystal solid solution field effect transistors

NASA Astrophysics Data System (ADS)

Kim, Youngjun; Cho, Seongeun; Park, Byoungnam

2018-03-01

We report ultraviolet (UV)-induced optical gating in a Zn1-x Mg x O nanocrystal solid solution (NCSS) field effect transistor (FET) through a systematic study in which UV-induced charge transport properties are probed as a function of Mg composition. Change in the electrical properties of Zn1-x Mg x O NCSS associated with electronic traps is investigated by field effect-modulated current-voltage characteristic curves in the dark and under illumination. Under UV illumination, significant threshold voltage shift to a more negative value in an n-channel Zn1-x Mg x O NCSS FET is observed. Importantly, as the Mg composition increases, the effect of UV illumination on the threshold voltage shift is alleviated. We found that threshold voltage shift as a function of Mg composition in the dark and under illumination is due to difference in the deep trap density in the Zn1-x Mg x O NCSS. This is supported by Mg composition dependent photoluminescence intensity in the visible range and reduced FET mobility with Mg addition. The presence of the deep traps and the corresponding trap energy levels in the Zn1-x Mg x O NCSS are ensured by photoelectron spectroscopy in air.

Mitochondrial threshold effects.

PubMed Central

Rossignol, Rodrigue; Faustin, Benjamin; Rocher, Christophe; Malgat, Monique; Mazat, Jean-Pierre; Letellier, Thierry

2003-01-01

The study of mitochondrial diseases has revealed dramatic variability in the phenotypic presentation of mitochondrial genetic defects. To attempt to understand this variability, different authors have studied energy metabolism in transmitochondrial cell lines carrying different proportions of various pathogenic mutations in their mitochondrial DNA. The same kinds of experiments have been performed on isolated mitochondria and on tissue biopsies taken from patients with mitochondrial diseases. The results have shown that, in most cases, phenotypic manifestation of the genetic defect occurs only when a threshold level is exceeded, and this phenomenon has been named the 'phenotypic threshold effect'. Subsequently, several authors showed that it was possible to inhibit considerably the activity of a respiratory chain complex, up to a critical value, without affecting the rate of mitochondrial respiration or ATP synthesis. This phenomenon was called the 'biochemical threshold effect'. More recently, quantitative analysis of the effects of various mutations in mitochondrial DNA on the rate of mitochondrial protein synthesis has revealed the existence of a 'translational threshold effect'. In this review these different mitochondrial threshold effects are discussed, along with their molecular bases and the roles that they play in the presentation of mitochondrial diseases. PMID:12467494

Effect of outpatient treatment of febrile neutropenia on the risk threshold for the use of CSF in patients with cancer treated with chemotherapy.

PubMed

Cosler, Leon E; Sivasubramaniam, Visaharan; Agboola, Olayemi; Crawford, Jeffrey; Dale, David; Lyman, Gary H

2005-01-01

Febrile neutropenia (FN) in patients with cancer treated with chemotherapy has traditionally been managed with inpatient broad-spectrum antibiotics until the infection and neutropenia have resolved. A newer strategy is outpatient oral or intravenous antibiotics in selected patients after an initial hospitalization. We sought to determine these costs, both overall and relative to those of traditional management, and the optimal role of prophylactic colony-stimulating factor (CSF) in patients at greatest risk for FN. Existing economic decision models were modified by incorporating a treatment strategy for FN in which patients are classified as high- and low-risk according to criteria described by Talcott. Low-risk patients were assumed to be treated as outpatients. Overall costs with the revised economic model were assessed and sensitivity analyses were performed. The costs of an episode of FN were estimated as 1) no CSF: dollar 13,355; 2) CSF with hospitalization for FN: dollar 8677; and 3) CSF with risk stratification and outpatient management in low-risk patients: dollar 8188. The risk threshold for the cost-effective use of CSF was only slightly lower with outpatient treatment. When all patients with FN are treated as inpatients and the cost of hospitalization is dollar 1750/day the risk threshold for FN at which prophylactic CSF becomes cost-effective is 16%. It is 15% when low-risk patients are treated as outpatients. Outpatient treatment slightly decreases the risk threshold for FN at which prophylactic CSF becomes cost-effective. The limited economic effect of this strategy may be because the patients who were at greatest risk of complications had significantly longer lengths of stay and accounted for most of the hospitalization costs.

Economic Evaluation of Dupilumab for the Treatment of Moderate-to-Severe Atopic Dermatitis in Adults.

PubMed

Kuznik, Andreas; Bégo-Le-Bagousse, Gaëlle; Eckert, Laurent; Gadkari, Abhijit; Simpson, Eric; Graham, Christopher N; Miles, LaStella; Mastey, Vera; Mahajan, Puneet; Sullivan, Sean D

2017-12-01

Dupilumab significantly improves signs and symptoms of atopic dermatitis (AD), including pruritus, symptoms of anxiety and depression, and health-related quality of life versus placebo in adults with moderate-to-severe AD. Since the cost-effectiveness of dupilumab has not been evaluated, the objective of this analysis was to estimate a value-based price range in which dupilumab would be considered cost-effective compared with supportive care (SC) for treatment of moderate-to-severe AD in an adult population. A health economic model was developed to evaluate from the US payer perspective the long-term costs and benefits of dupilumab treatment administered every other week (q2w). Dupilumab q2w was compared with SC; robustness of assumptions and results were tested using sensitivity and scenario analyses. Clinical data were derived from the dupilumab LIBERTY AD SOLO trials; healthcare use and cost data were from health insurance claims histories of adult patients with AD. The annual price of maintenance therapy with dupilumab to be considered cost-effective was estimated for decision thresholds of US$100,000 and $150,000 per quality-adjusted life-year (QALY) gained. In the base case, the annual maintenance price for dupilumab therapy to be considered cost-effective would be $28,770 at a $100,000 per QALY gained threshold, and $39,940 at a $150,000 threshold. Results were generally robust to parameter variations in one-way and probabilistic sensitivity analyses. Dupilumab q2w compared with SC is cost-effective for the treatment of moderate-to-severe AD in US adults at an annual price of maintenance therapy in the range of $29,000-$40,000 at the $100,000-$150,000 per QALY thresholds. Sanofi and Regeneron Pharmaceuticals, Inc.

The facilitating effect of systemic administration of Kv7/M channel blocker XE991 on LTP induction in the hippocampal CA1 area independent of muscarinic activation.

PubMed

Song, Ming-Ke; Cui, Yong-Yao; Zhang, Wei-Wei; Zhu, Liang; Lu, Yang; Chen, Hong-Zhuan

2009-09-11

A large amount of in vitro studies demonstrate suppression of M-current in hippocampal neurons by Kv7/M channel blocker results in depolarization of membrane potential and release of neurotransmitters, such as acetylcholine and glutamate, suggesting that Kv7/M channel may play important roles in regulating synaptic plasticity. In the present study, we examined the in vivo effect of Kv7/M channel inhibition on the long-term potentiation (LTP) induction at basal dendrites in hippocampal CA1 area of urethane-anaesthetized rats. The Kv7/M channel was inhibited by intraperitoneal injection of XE991 (10mg/kg) and the LTP of field excitatory postsynaptic potential (fEPSP) was induced by supra-threshold high frequency stimulation (S1 HFS). A weak protocol which was just below the threshold for evoking LTP was used as sub-threshold high frequency stimulation (S2 HFS). XE991 did not significantly alter the slope of fEPSP and the magnitude of LTP induced by S1 HFS, suggesting that Kv7/M channel inhibition had little or no effect on glutamatergic transmission under basal conditions. However, XE991 could make S2 HFS evoke LTP even after the application of the muscarinic cholinergic (mACh) receptor antagonist scopolamine, suggesting that Kv7/M channel inhibition lowered the threshold for LTP induction and the effect was independent of muscarinic activation. Based on the above findings, we concluded that the facilitating effect of XE991 on LTP induction is not mediated by its ability to enhance the release of acetylcholine; therefore, Kv7/M channel blockers may provide a therapeutic benefit to cholinergic deficiency-related cognitive impairment, e.g., Alzheimer's disease.

The Effects of Preconscious Cues upon the Automatic Activation of Self-Esteem of Selected Middle School Students.

ERIC Educational Resources Information Center

Ledford, Bruce R.; Ledford, Suzanne Y.

This study investigated whether grade six students' self-esteem could be affected by the presentation of a selected stimulus below the threshold of conscious awareness via the medium of a specially prepared paper. It also investigated whether any statistically significant differences existed between the effects on self-esteem of a selected…

Neurometric amplitude-modulation detection threshold in the guinea-pig ventral cochlear nucleus

PubMed Central

Sayles, Mark; Füllgrabe, Christian; Winter, Ian M

2013-01-01

Amplitude modulation (AM) is a pervasive feature of natural sounds. Neural detection and processing of modulation cues is behaviourally important across species. Although most ecologically relevant sounds are not fully modulated, physiological studies have usually concentrated on fully modulated (100% modulation depth) signals. Psychoacoustic experiments mainly operate at low modulation depths, around detection threshold (∼5% AM). We presented sinusoidal amplitude-modulated tones, systematically varying modulation depth between zero and 100%, at a range of modulation frequencies, to anaesthetised guinea-pigs while recording spikes from neurons in the ventral cochlear nucleus (VCN). The cochlear nucleus is the site of the first synapse in the central auditory system. At this locus significant signal processing occurs with respect to representation of AM signals. Spike trains were analysed in terms of the vector strength of spike synchrony to the amplitude envelope. Neurons showed either low-pass or band-pass temporal modulation transfer functions, with the proportion of band-pass responses increasing with increasing sound level. The proportion of units showing a band-pass response varies with unit type: sustained chopper (CS) > transient chopper (CT) > primary-like (PL). Spike synchrony increased with increasing modulation depth. At the lowest modulation depth (6%), significant spike synchrony was only observed near to the unit's best modulation frequency for all unit types tested. Modulation tuning therefore became sharper with decreasing modulation depth. AM detection threshold was calculated for each individual unit as a function of modulation frequency. Chopper units have significantly better AM detection thresholds than do primary-like units. AM detection threshold is significantly worse at 40 dB vs. 10 dB above pure-tone spike rate threshold. Mean modulation detection thresholds for sounds 10 dB above pure-tone spike rate threshold at best modulation frequency are (95% CI) 11.6% (10.0–13.1) for PL units, 9.8% (8.2–11.5) for CT units, and 10.8% (8.4–13.2) for CS units. The most sensitive guinea-pig VCN single unit AM detection thresholds are similar to human psychophysical performance (∼3% AM), while the mean neurometric thresholds approach whole animal behavioural performance (∼10% AM). PMID:23629508

Improving Image Quality of Coronary Computed Tomography Angiography Using Patient Weight and Height-Dependent Scan Trigger Threshold.

PubMed

Kang, Deqiang; Hua, Haiqin; Peng, Nan; Zhao, Jing; Wang, Zhiqun

2017-04-01

We aim to improve the image quality of coronary computed tomography angiography (CCTA) by using personalized weight and height-dependent scan trigger threshold. This study was divided into two parts. First, we performed and analyzed the 100 scheduled CCTA data, which were acquired by using body mass index-dependent Smart Prep sequence (trigger threshold ranged from 80 Hu to 250 Hu based on body mass index). By identifying the cases of high quality image, a linear regression equation was established to determine the correlation among the Smart Prep threshold, height, and body weight. Furthermore, a quick search table was generated for weight and height-dependent Smart Prep threshold in CCTA scan. Second, to evaluate the effectiveness of the new individual threshold method, an additional 100 consecutive patients were divided into two groups: individualized group (n = 50) with weight and height-dependent threshold and control group (n = 50) with the conventional constant threshold of 150 HU. Image quality was compared between the two groups by measuring the enhancement in coronary artery, aorta, left and right ventricle, and inferior vena cava. By visual inspection, image quality scores were performed to compare between the two groups. Regression equation between Smart Prep threshold (K, Hu), height (H, cm), and body weight (BW, kg) was K = 0.811 × H + 1.917 × BW - 99.341. When compared to the control group, the individualized group presented an average overall increase of 12.30% in enhancement in left main coronary artery, 12.94% in proximal right coronary artery, and 10.6% in aorta. Correspondingly, the contrast-to-noise ratios increased by 26.03%, 27.08%, and 23.17%, respectively, and by 633.1% in contrast between aorta and left ventricle. Meanwhile, the individualized group showed an average overall decrease of 22.7% in enhancement of right ventricle and 32.7% in inferior vena cava. There was no significant difference of the image noise between the two groups (P > .05). By visual inspection, the image quality score of the individualized group was higher than that of the control group. Using personalized weight and height-dependent Smart Prep threshold to adjust scan trigger time can significantly improve the image quality of CCTA. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Spacer engineered Trigate SOI TFET: An investigation towards harsh temperature environment applications

NASA Astrophysics Data System (ADS)

Mallikarjunarao; Ranjan, Rajeev; Pradhan, K. P.; Artola, L.; Sahu, P. K.

2016-09-01

In this paper, a novel N-channel Tunnel Field Effect Transistor (TFET) i.e., Trigate Silicon-ON-Insulator (SOI) N-TFET with high-k spacer is proposed for better Sub-threshold swing (SS) and OFF-state current (IOFF) by keeping in mind the sensitivity towards temperature. The proposed model can achieve a Sub-threshold swing less than 35 mV/decade at various temperatures, which is desirable for designing low power CTFET for digital circuit applications. In N-TFET source doping has a significant effect on the ON-state current (ION) level; therefore more electrons will tunnel from source to channel region. High-k Spacer i.e., HfO2 is used to enhance the device performance and also it avoids overlapping of transistors in an integrated circuits (IC's). We have designed a reliable device by performing the temperature analysis on Transfer characteristics, Drain characteristics and also on various performance metrics like ON-state current (ION), OFF-state current (IOFF), ION/IOFF, Trans-conductance (gm), Trans-conductance Generation Factor (TGF), Sub-threshold Swing (SS) to observe the applications towards harsh temperature environment.

Method of Improved Fuzzy Contrast Combined Adaptive Threshold in NSCT for Medical Image Enhancement

PubMed Central

Yang, Jie; Kasabov, Nikola

2017-01-01

Noises and artifacts are introduced to medical images due to acquisition techniques and systems. This interference leads to low contrast and distortion in images, which not only impacts the effectiveness of the medical image but also seriously affects the clinical diagnoses. This paper proposes an algorithm for medical image enhancement based on the nonsubsampled contourlet transform (NSCT), which combines adaptive threshold and an improved fuzzy set. First, the original image is decomposed into the NSCT domain with a low-frequency subband and several high-frequency subbands. Then, a linear transformation is adopted for the coefficients of the low-frequency component. An adaptive threshold method is used for the removal of high-frequency image noise. Finally, the improved fuzzy set is used to enhance the global contrast and the Laplace operator is used to enhance the details of the medical images. Experiments and simulation results show that the proposed method is superior to existing methods of image noise removal, improves the contrast of the image significantly, and obtains a better visual effect. PMID:28744464

Across-channel interference in intensity discrimination: The role of practice and listening strategy

PubMed Central

Buss, Emily

2008-01-01

Pure tone intensity discrimination thresholds can be elevated by the introduction of remote maskers with roved level. This effect is on the order of 10 dB [10log(ΔI/I)] in some conditions and can be demonstrated under conditions of little or no energetic masking. The current study examined the effect of practice and observer strategy on this phenomenon. Experiment 1 included observers who had no formal experience with intensity discrimination and provided training over six hours on a single masked intensity discrimination task to assess learning effects. Thresholds fell with practice for most observers, with significant improvements in 6 out of 8 cases. Despite these improvements significant masking remained in all cases. The second experiment assessed trial-by-trial effects of roved masker level. Conditional probability of a ‘signal-present’ response as a function of the rove value assigned to each of the two masker tones indicates fundamental differences among observers’ processing strategies, even after six hours of practice. The variability in error patterns across practiced listeners suggests that observers approach the task differently, though this variability does not appear to be related to sensitivity. PMID:18177156

Alternating frequencies of transcutaneous electric nerve stimulation: does it produce greater analgesic effects on mechanical and thermal pain thresholds?

PubMed

Tong, K C; Lo, Sing Kai; Cheing, Gladys L

2007-10-01

To determine whether alternating frequency transcutaneous electric nerve stimulation (TENS) at 2 and 100Hz (2/100Hz) has a more potent hypoalgesic effect than a fixed frequency at 2 or 100Hz in healthy participants. A single-blind randomized controlled trial with a convenience sample. University physiotherapy department. Sixty-four healthy volunteers (32 men [mean age, 28.1+/-5.9y], 32 women [mean age, 27.7+/-5.6y]) were recruited and randomly divided into 4 groups. The 4 groups received TENS delivered at (1) 2Hz; (2) 100Hz; (3) 2/100Hz alternating frequency; and (4) no treatment (control group), respectively. Electric stimulation was applied over the anterior aspect of the dominant forearm for 30 minutes. Mechanical pain thresholds (MPTs) and heat pain thresholds (HPTs) were recorded before, during, and after TENS stimulation. The data were analyzed using linear mixed models, with group treated as a between-subject factor and time a within-subject factor. During and shortly after electric stimulation, HPT increased significantly in the alternating frequency stimulation group (P=.024). MPT increased significantly in both the 100Hz (P=.008) and the alternating frequency groups (P=.012), but the increase was substantially larger in the 100Hz group. Alternating frequency stimulation produced a greater elevation in the HPT, but a greater increase in the MPT was achieved using 100Hz stimulation.

Hormonal Responses to Active and Passive Recovery After Load Carriage.

PubMed

Taipale, Ritva S; Heinaru, Siiri; Nindl, Bradley C; Vaara, Jani P; Santtila, Matti; Häkkinen, Keijo; Kyröläinen, Heikki

2015-11-01

Military operations often induce fatigue resulting from load carriage. Recovery promotes military readiness. This study investigated the acute effects of AR vs. PR after load carriage on maximal isometric leg extension force (MVC) and serum hormonal concentrations. Male reservists (27 ± 3 years, 180 ± 7 cm, 74 ± 11 kg, V[Combining Dot Above]O2max 64 ± 9 ml·kg⁻¹·min⁻¹) completed PR (n = 8) or AR (n = 8) after 50 minutes of loaded (16 kg) uphill (gradient 4.0%) treadmill marching at individual anaerobic threshold. No differences were observed between groups in relative changes in MVC during the marching loading, after AR or PR or the next morning. Significant differences in relative responses to AR and PR postmarching loading were observed in serum testosterone (T), cortisol, and sex-hormone binding globulin immediately post AR and PR; however the next morning, all serum hormone concentrations had returned to normal. This study did not reveal any significant differences between the effects of AR and PR after an hour-long marching protocol at approximately anaerobic threshold on MVC or serum hormones the morning after the experimental marching protocol. Thus, based on the variable measured in this study, marching performed by physically fit army reservists at an intensity at or below anaerobic threshold may not necessitate specialized recovery protocols.