Mutational effects of γ-rays and carbon ion beams on Arabidopsis seedlings

PubMed Central

Yoshihara, Ryouhei; Nozawa, Shigeki; Hase, Yoshihiro; Narumi, Issay; Hidema, Jun; Sakamoto, Ayako N.

2013-01-01

To assess the mutational effects of radiation on vigorously proliferating plant tissue, the mutation spectrum was analyzed with Arabidopsis seedlings using the plasmid-rescue method. Transgenic plants containing the Escherichia coli rpsL gene were irradiated with γ-rays and carbon ion beams (320-MeV 12C6+), and mutations in the rpsL gene were analyzed. Mutant frequency increased significantly following irradiation by γ-rays, but not by 320-MeV 12C6+. Mutation spectra showed that both radiations increased the frequency of frameshifts and other mutations, including deletions and insertions, but only γ-rays increased the frequency of total base substitutions. These results suggest that the type of DNA lesions which cause base substitutions were less often induced by 320-MeV 12C6+ than by γ-rays in Arabidopsis seedlings. Furthermore, γ-rays never increased the frequencies of G:C to T:A or A:T to C:G transversions, which are caused by oxidized guanine; 320-MeV 12C6+, however, produced a slight increase in both transversions. Instead, γ-rays produced a significant increase in the frequency of G:C to A:T transitions. These results suggest that 8-oxoguanine has little effect on mutagenesis in Arabidopsis cells. PMID:23728320

Preference and intake frequency of high sodium foods and dishes and their correlations with anthropometric measurements among Malaysian subjects

PubMed Central

Choong, Stella Sinn-Yee; Balan, Sumitha Nair; Chua, Leong-Siong

2012-01-01

This study investigated the preference and intake frequency of a list of 15 commonly available high sodium Malaysian foods/dishes, discretionary salt use, and their possible association with demographics, blood pressures and anthropometric measurements among 300 Malaysian university students (114 males, 186 females; 259 ethnic Chinese, 41 Indians; 220 lean, 80 overweight). French fries and instant soup noodle were found to be the most preferred and most frequently consumed salty food, respectively, while salted fish was least preferred and least frequently consumed. Males had a significantly higher intake frequency of at least 6 of the salty foods, but the preference of most salty foods was not significantly different between genders. Ethnic Chinese significantly preferred more and took more frequently traditional and conventional Malaysian foods like asam laksa (a Malaysian salty-sour-spicy noodle in fish stock), salted biscuits and salted vegetable, while Indians have more affinity and frequency towards eating salty Western foods. Body Mass Index was significantly negatively correlated with the intake frequency of canned/packet soup and salted fish while waist circumference was significantly positively correlated with the preference of instant noodle. Also, an increased preference of potato chips and intake frequency of salted biscuits seemed to lead to a decreased WHR. Other than these, all the other overweight/obesity indicators did not seem to fully correlate with the salty food preference and intake frequency. Nevertheless, the preference and intake frequency of asam laksa seemed to be significant negative predictors for blood pressures. Finally, increased preference and intake frequency of high sodium shrimp paste (belacan)-based foods like asam laksa and belacan fried rice seemed to discourage discretionary salt use. In conclusion, the preference and intake frequency of the high sodium belacan-based dish asam laksa seems to be a good predictor for ethnic difference, discretionary salt use and blood pressures. PMID:22808349

Preference and intake frequency of high sodium foods and dishes and their correlations with anthropometric measurements among Malaysian subjects.

PubMed

Choong, Stella Sinn-Yee; Balan, Sumitha Nair; Chua, Leong-Siong; Say, Yee-How

2012-06-01

This study investigated the preference and intake frequency of a list of 15 commonly available high sodium Malaysian foods/dishes, discretionary salt use, and their possible association with demographics, blood pressures and anthropometric measurements among 300 Malaysian university students (114 males, 186 females; 259 ethnic Chinese, 41 Indians; 220 lean, 80 overweight). French fries and instant soup noodle were found to be the most preferred and most frequently consumed salty food, respectively, while salted fish was least preferred and least frequently consumed. Males had a significantly higher intake frequency of at least 6 of the salty foods, but the preference of most salty foods was not significantly different between genders. Ethnic Chinese significantly preferred more and took more frequently traditional and conventional Malaysian foods like asam laksa (a Malaysian salty-sour-spicy noodle in fish stock), salted biscuits and salted vegetable, while Indians have more affinity and frequency towards eating salty Western foods. Body Mass Index was significantly negatively correlated with the intake frequency of canned/packet soup and salted fish while waist circumference was significantly positively correlated with the preference of instant noodle. Also, an increased preference of potato chips and intake frequency of salted biscuits seemed to lead to a decreased WHR. Other than these, all the other overweight/obesity indicators did not seem to fully correlate with the salty food preference and intake frequency. Nevertheless, the preference and intake frequency of asam laksa seemed to be significant negative predictors for blood pressures. Finally, increased preference and intake frequency of high sodium shrimp paste (belacan)-based foods like asam laksa and belacan fried rice seemed to discourage discretionary salt use. In conclusion, the preference and intake frequency of the high sodium belacan-based dish asam laksa seems to be a good predictor for ethnic difference, discretionary salt use and blood pressures.

Effect of Frequency and Waveform on Inactivation of Escherichia coli O157:H7 and Salmonella enterica Serovar Typhimurium in Salsa by Ohmic Heating

PubMed Central

Lee, Su-Yeon; Ryu, Sangryeol

2013-01-01

The effect of frequency of alternating current during ohmic heating on electrode corrosion, heating rate, inactivation of food-borne pathogens, and quality of salsa was investigated. The impact of waveform on heating rate was also investigated. Salsa was treated with various frequencies (60 Hz to 20 kHz) and waveforms (sine, square, and sawtooth) at a constant electric field strength of 12.5 V/cm. Electrode corrosion did not occur when the frequency exceeded 1 kHz. The heating rate of the sample was dependent on frequency up to 500 Hz, but there was no significant difference (P > 0.05) in the heating rate when the frequency was increased above 1 kHz. The electrical conductivity of the sample increased with a rise in the frequency. At a frequency of 60 Hz, the square wave produced a lower heating rate than that of sine and sawtooth waves. The heating rate between waveforms was not significantly (P > 0.05) different when the frequency was >500 Hz. As the frequency increased, the treatment time required to reduce Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium to below the detection limit (1 log CFU/g) decreased without affecting product quality. These results suggest that ohmic heating can be effectively used to pasteurize salsa and that the effect of inactivation is dependent on frequency and electrical conductivity rather than waveform. PMID:23023752

Effect of frequency and waveform on inactivation of Escherichia coli O157:H7 and Salmonella enterica Serovar Typhimurium in salsa by ohmic heating.

PubMed

Lee, Su-Yeon; Ryu, Sangryeol; Kang, Dong-Hyun

2013-01-01

The effect of frequency of alternating current during ohmic heating on electrode corrosion, heating rate, inactivation of food-borne pathogens, and quality of salsa was investigated. The impact of waveform on heating rate was also investigated. Salsa was treated with various frequencies (60 Hz to 20 kHz) and waveforms (sine, square, and sawtooth) at a constant electric field strength of 12.5 V/cm. Electrode corrosion did not occur when the frequency exceeded 1 kHz. The heating rate of the sample was dependent on frequency up to 500 Hz, but there was no significant difference (P > 0.05) in the heating rate when the frequency was increased above 1 kHz. The electrical conductivity of the sample increased with a rise in the frequency. At a frequency of 60 Hz, the square wave produced a lower heating rate than that of sine and sawtooth waves. The heating rate between waveforms was not significantly (P > 0.05) different when the frequency was >500 Hz. As the frequency increased, the treatment time required to reduce Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium to below the detection limit (1 log CFU/g) decreased without affecting product quality. These results suggest that ohmic heating can be effectively used to pasteurize salsa and that the effect of inactivation is dependent on frequency and electrical conductivity rather than waveform.

Late administration of high-frequency electrical stimulation increases nerve regeneration without aggravating neuropathic pain in a nerve crush injury.

PubMed

Su, Hong-Lin; Chiang, Chien-Yi; Lu, Zong-Han; Cheng, Fu-Chou; Chen, Chun-Jung; Sheu, Meei-Ling; Sheehan, Jason; Pan, Hung-Chuan

2018-06-25

High-frequency transcutaneous neuromuscular electrical nerve stimulation (TENS) is currently used for the administration of electrical current in denervated muscle to alleviate muscle atrophy and enhance motor function; however, the time window (i.e. either immediate or delayed) for achieving benefit is still undetermined. In this study, we conducted an intervention of sciatic nerve crush injury using high-frequency TENS at different time points to assess the effect of motor and sensory functional recovery. Animals with left sciatic nerve crush injury received TENS treatment starting immediately after injury or 1 week later at a high frequency(100 Hz) or at a low frequency (2 Hz) as a control. In SFI gait analysis, either immediate or late admission of high-frequency electrical stimulation exerted significant improvement compared to either immediate or late administration of low-frequency electrical stimulation. In an assessment of allodynia, immediate high frequency electrical stimulation caused a significantly decreased pain threshold compared to late high-frequency or low-frequency stimulation at immediate or late time points. Immunohistochemistry staining and western blot analysis of S-100 and NF-200 demonstrated that both immediate and late high frequency electrical stimulation showed a similar effect; however the effect was superior to that achieved with low frequency stimulation. Immediate high frequency electrical stimulation resulted in significant expression of TNF-α and synaptophysin in the dorsal root ganglion, somatosensory cortex, and hippocampus compared to late electrical stimulation, and this trend paralleled the observed effect on somatosensory evoked potential. The CatWalk gait analysis also showed that immediate electrical stimulation led to a significantly high regularity index. In primary dorsal root ganglion cells culture, high-frequency electrical stimulation also exerted a significant increase in expression of TNF-α, synaptophysin, and NGF in accordance with the in vivo results. Immediate or late transcutaneous high-frequency electrical stimulation exhibited the potential to stimulate the motor nerve regeneration. However, immediate electrical stimulation had a predilection to develop neuropathic pain. A delay in TENS initiation appears to be a reasonable approach for nerve repair and provides the appropriate time profile for its clinical application.

Evaluation of microtensile and tensile bond strength tests determining effects of erbium, chromium: yttrium-scandium-gallium-garnet laser pulse frequency on resin-enamel bonding.

PubMed

Yildirim, T; Ayar, M K; Yesilyurt, C; Kilic, S

2016-01-01

The aim of the present study was to compare two different bond strength test methods (tensile and microtensile) in investing the influence of erbium, chromium: yttrium-scandium-gallium-garnet (Er, Cr: YSGG) laser pulse frequency on resin-enamel bonding. One-hundred and twenty-five bovine incisors were used in the present study. Two test methods were used: Tensile bond strength (TBS; n = 20) and micro-TBS (μTBS; n = 5). Those two groups were further split into three subgroups according to Er, Cr: YSGG laser frequency (20, 35, and 50 Hz). Following adhesive procedures, microhybrid composite was placed in a custom-made bonding jig for TBS testing and incrementally for μTBS testing. TBS and μTBS tests were carried out using a universal testing machine and a microtensile tester, respectively. Analysis of TBS results showed that means were not significantly different. For μTBS, the Laser-50 Hz group showed the highest bond strength (P < 0.05), and increasing frequency significantly increased bond strength (P < 0.05). Comparing the two tests, the μTBS results showed higher means and lower standard deviations. It was demonstrated that increasing μTBS pulse frequency significantly improved immediate bond strength while TBS showed no significant effect. It can, therefore, be concluded that test method may play a significant role in determining optimum laser parameters for resin bonding.

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.

Direct and correlated responses to artificial selection on male mating frequency in the stalk-eyed fly Cyrtodiopsis dalmanni.

PubMed

Rogers, D W; Baker, R H; Chapman, T; Denniff, M; Pomiankowski, A; Fowler, K

2005-05-01

Traditionally it was thought that fitness-related traits such as male mating frequency, with a history of strong directional selection, should have little additive genetic variance and thus respond asymmetrically to bidirectional artificial selection. However, recent findings and theory suggest that a balance between selection for increased male mating frequency and opposing selection pressures on physiologically linked traits will cause male mating frequency to have high additive genetic variation and hence respond symmetrically to selection. We tested these hypotheses in the stalk-eyed fly, Cyrtodiopsis dalmanni, in which males hold harems comprising many females and so have the opportunity to mate at extremely high frequencies. We subjected male stalk-eyed flies to artificial selection for increased ('high') and decreased ('low') mating frequency in the presence of ecologically realistic, high numbers of females. High line males mated significantly more often than control or low line males. The direct response to selection was approximately symmetric in the high and low lines, revealing high additive genetic variation for, and no significant genetic constraints on, increased male mating frequency in C. dalmanni. In order to investigate trade-offs that might constrain male mating frequency under natural conditions we examined correlated responses to artificial selection. We measured accessory gland length, testis length and eyespan after 7 and 14 generations of selection. High line males had significantly larger accessory glands than low line males. No consistent correlated responses to selection were found in testis length or eyespan. Our results suggest that costs associated with the production and maintenance of large accessory glands, although yet to be identified, are likely to be a major constraint on mating frequency in natural populations of C. dalmanni.

Linear response of mutans streptococci to increasing frequency of xylitol chewing gum use: a randomized controlled trial [ISRCTN43479664].

PubMed

Ly, Kiet A; Milgrom, Peter; Roberts, Marilyn C; Yamaguchi, David K; Rothen, Marilynn; Mueller, Greg

2006-03-24

Xylitol is a naturally occurring sugar substitute that has been shown to reduce the level of mutans streptococci in plaque and saliva and to reduce tooth decay. It has been suggested that the degree of reduction is dependent on both the amount and the frequency of xylitol consumption. For xylitol to be successfully and cost-effectively used in public health prevention strategies dosing and frequency guidelines should be established. This study determined the reduction in mutans streptococci levels in plaque and unstimulated saliva to increasing frequency of xylitol gum use at a fixed total daily dose of 10.32 g over five weeks. Participants (n = 132) were randomized to either active groups (10.32 g xylitol/day) or a placebo control (9.828 g sorbitol and 0.7 g maltitol/day). All groups chewed 12 pieces of gum per day. The control group chewed 4 times/day and active groups chewed xylitol gum at a frequency of 2 times/day, 3 times/day, or 4 times/day. The 12 gum pieces were evenly divided into the frequency assigned to each group. Plaque and unstimulated saliva samples were taken at baseline and five-weeks and were cultured on modified Mitis Salivarius agar for mutans streptococci enumeration. There were no significant differences in mutans streptococci level among the groups at baseline. At five-weeks, mutans streptococci levels in plaque and unstimulated saliva showed a linear reduction with increasing frequency of xylitol chewing gum use at the constant daily dose. Although the difference observed for the group that chewed xylitol 2 times/day was consistent with the linear model, the difference was not significant. There was a linear reduction in mutans streptococci levels in plaque and saliva with increasing frequency of xylitol gum use at a constant daily dose. Reduction at a consumption frequency of 2 times per day was small and consistent with the linear-response line but was not statistically significant.

The Nightmares of Sleep Apnea: Nightmare Frequency Declines with Increasing Apnea Hypopnea Index

PubMed Central

Pagel, J. F.; Kwiatkowski, Carol

2010-01-01

Objective: To clarify the association of reported nightmare recall with polysomnographically defined obstructive sleep apnea (OSA) in a sleep laboratory population. Methods: This study included 393 individuals undergoing clinical polysomnography including a general intake questionnaire with questions on dream and nightmare recall frequency. Mean age was 50.5 and a range of 13 to 82 years, with 33% of the sample female and 67% male. Reported dream and nightmare recall were classified as infrequent when reported at less than once a month, or frequent when reported at a frequency greater than once per week. Results: Mean Apnea-hypopnea Index AHI was 34.9 (std. 32.0) indicating a high frequency of severe (AHI > 30) OSA in this clinical study population. Both AHI and Apnea Index (AI) were significantly higher (p = 0.000) for the grouping reporting infrequent nightmare recall. As the AHI score increased, the percent of participants with frequent nightmare recall decreased linearly. Conclusion: Patients with higher AHI report a lower nightmare frequency, indicating that significant OSA suppresses the cognitive experience of nightmare recall. Depressed nightmare recall may occur secondary to the REMS suppression know to occur in patients with significant OSA. Citation: Pagel JF; Kwiatkowski C. The nightmares of sleep apnea: nightmare frequency declines with increasing apnea hypopnea index. J Clin Sleep Med 2010;6(1):69-73. PMID:20191941

Response localization of the pharmacological agents histamine and salbutamol along the respiratory system by forced oscillations in asthmatic subjects.

PubMed

Wouters, E F; Polko, A H; Visser, B F

1989-01-01

The bronchodilating effect of 1 mg and 0.4 mg salbutamol on the impedance of the respiratory system was studied in 25 asthmatic subjects after histamine-induced bronchoconstriction. Histamine caused an increase of respiratory resistance (Rrs) at lower frequencies and a frequency dependence of Rrs. Respiratory reactance (Xrs) decreased at all frequencies after histamine challenge. These changes can be explained by peripheral airway obstruction. Impedance measurements performed 5 min after inhalation of 1 mg and 0.4 mg salbutamol showed a decrease of Rrs values at lower frequencies, a disappearance of the frequency dependence of Rrs, and a significant increase of Xrs values. No significant differences in absolute changes of Rrs and Xrs are observed between the salbutamol regimens. These changes after inhalation of salbutamol can be explained by supposing a predominant action on the peripheral airways.

Chemotherapy ± cetuximab modulates peripheral immune responses in metastatic colorectal cancer.

PubMed

Xynos, Ioannis D; Karadima, Maria L; Voutsas, Ioannis F; Amptoulach, Sousana; Skopelitis, Elias; Kosmas, Christos; Gritzapis, Angelos D; Tsavaris, Nikolas

2013-01-01

To identify changes in peripheral immune responses in patients with metastatic colorectal cancer (mCRC) treated with irinotecan/5-fluorouracil/leucovorin (IFL) alone or in combination with cetuximab (C-IFL). Peripheral blood mononuclear cells (PBMCs) collected from healthy donors (n = 20) and patients with mCRC receiving treatment with either IFL (n = 30) or C-IFL (n = 30) were tested for cytokine production upon polyclonal stimulation with anti-CD3 monoclonal antibody, T cell proliferation in the autologous mixed lymphocyte reaction (auto-MLR) and T regulatory cell (Treg) frequency. The respective results were evaluated over two treatment cycles and further assessed in relation to response to treatment. PBMCs prior to treatment exhibited significantly lower production of IL-2, IFN-γ, IL-12 and IL-18 cytokines and lower auto-MLR responses, whereas Treg frequency, IL-4, IL-10 cytokines were increased compared to healthy donors. During treatment, IL-2, IFN-γ, IL-12, IL-18 and auto-MLR responses increased, while Treg frequency and IL-10 secretion decreased significantly compared to the baseline. Responders to treatment exhibited a significantly higher increase in IL-2, IFN-γ, IL-12 and IL-18 production and auto-MLR responses, and higher decrease in IL-4, IL-10 secretion and Treg frequency. Among all patient subgroups analysed, responders to C-IFL demonstrated significantly higher increase in auto-MLR responses, IL-12 and IL-18 secretion and higher decrease in Treg frequency. The disturbed immune parameters observed in patients with mCRC at presentation can be significantly improved during treatment with IFL and this effect can be potentiated by the addition of cetuximab. Monitoring of the peripheral immune system function could be used as surrogate marker in predicting treatment-related outcome. Copyright © 2013 S. Karger AG, Basel.

Pedunculopontine nucleus stimulation improves akinesia in a Parkinsonian monkey.

PubMed

Jenkinson, Ned; Nandi, Dipankar; Miall, R Chris; Stein, John F; Aziz, Tipu Z

2004-12-03

We have studied the effects of stimulating the pedunculopontine nuclei through a fully implanted macroelectrode with a s.c. implantable pulse generator whose parameters can be programmed telemetrically, in a macaque before and after inducing Parkinsonian akinesia with MPTP. Our results show that in the normal monkey high frequency stimulation of the pedunculopontine nuclei reduces motor activity while low frequency stimulation increases it significantly over baseline. After making the monkey Parkinsonian with MPTP, unilateral low frequency stimulation of the pedunculopontine nuclei led to significant increases in activity. These results suggest that pedunculopontine nuclei stimulation could be clinically effective in treating advanced Parkinson's disease and other akinetic disorders.

Frequency-dependent acceleration of relaxation in mammalian heart: a property not relying on phospholamban and SERCA2a phosphorylation

PubMed Central

Valverde, Carlos A; Mundiña-Weilenmann, Cecilia; Said, Matilde; Ferrero, Paola; Vittone, Leticia; Salas, Margarita; Palomeque, Julieta; Petroff, Martín Vila; Mattiazzi, Alicia

2005-01-01

An increase in stimulation frequency causes an acceleration of myocardial relaxation (FDAR). Several mechanisms have been postulated to explain this effect, among which is the Ca2+–calmodulin-dependent protein kinase (CaMKII)-dependent phosphorylation of the Thr17 site of phospholamban (PLN). To gain further insights into the mechanisms of FDAR, we studied the FDAR and the phosphorylation of PLN residues in perfused rat hearts, cat papillary muscles and isolated cat myocytes. This allowed us to sweep over a wide range of frequencies, in species with either positive or negative force–frequency relationships, as well as to explore the FDAR under isometric (or isovolumic) and isotonic conditions. Results were compared with those produced by isoprenaline, an intervention known to accelerate relaxation (IDAR) via PLN phosphorylation. While IDAR occurs tightly associated with a significant increase in the phosphorylation of Ser16 and Thr17 of PLN, FDAR occurs without significant changes in the phosphorylation of PLN residues in the intact heart and cat papillary muscles. Moreover, in intact hearts, FDAR was not associated with any significant change in the CaMKII-dependent phosphorylation of sarcoplasmic/endoplasmic Ca2+ ATPase (SERCA2a), and was not affected by the presence of the CaMKII inhibitor, KN-93. In isolated myocytes, FDAR occurred associated with an increase in Thr17 phosphorylation. However, for a similar relaxant effect produced by isoprenaline, the phosphorylation of PLN (Ser16 and Thr17) was significantly higher in the presence of the β-agonist. Moreover, the time course of Thr17 phosphorylation was significantly delayed with respect to the onset of FDAR. In contrast, the time course of Ser16 phosphorylation, the first residue that becomes phosphorylated with isoprenaline, was temporally associated with IDAR. Furthermore, KN-93 significantly decreased the phosphorylation of Thr17 that was evoked by increasing the stimulation frequency, but failed to affect FDAR. Taken together, the results provide direct evidence indicating that CaMKII phosphorylation pathways are not involved in FDAR and that FDAR and IDAR do not share a common underlying mechanism. More likely, a CaMKII-independent mechanism could be involved, whereby increasing stimulation frequency would disrupt the SERCA2a–PLN interaction, leading to an increase in SR Ca2+ uptake and myocardial relaxation. PMID:15528241

[Study the impacts of diagnosis on occupational noise-induced deafness after bring into the different high frequency hearing threshold weighted value].

PubMed

Xue, L J; Yang, A C; Chen, H; Huang, W X; Guo, J J; Liang, X Y; Chen, Z Q; Zheng, Q L

2017-11-20

Objective: Study of the results and the degree on occupational noise-induced deafness in-to the different high frequency hearing threshold weighted value, in order to provide theoretical basis for the re-vision of diagnostic criteria on occupational noise-induced deafness. Methods: A retrospective study was con-ducted to investigate the cases on the diagnosis of occupational noise-induced deafness in Guangdong province hospital for occupational disease prevention and treatment from January 2016 to January 2017. Based on the re-sults of the 3 hearing test for each test interval greater than 3 days in the hospital, the best threshold of each frequency was obtained, and based on the diagnostic criteria of occupational noise deafness in 2007 edition, Chi square test, t test and variance analysis were used to measure SPSS21.0 data, their differences are tested among the means of speech frequency and the high frequency weighted value into different age group, noise ex-posure group, and diagnostic classification between different dimensions. Results: 1. There were totally 168 cases in accordance with the study plan, male 154 cases, female 14 cases, the average age was 41.18 ±6.07 years old. 2. The diagnosis rate was increased into the weighted value of different high frequency than the mean value of pure speech frequency, the weighted 4 kHz frequency increased by 13.69% (χ(2)=9.880, P =0.002) , 6 kHz increased by 15.47% (χ(2)=9.985, P =0.002) and 4 kHz+6 kHz increased by15.47% (χ(2)=9.985, P =0.002) , the difference was statistically significant. The diagnostic rate of different high threshold had no obvious differ-ence between the genders. 3. The age groups were divided into less than or equal to 40years old group (A group) and 40-50 years old group (group B) , there were higher the diagnostic rate between high frequency weighted 4 kHz (A group χ(2)=3.380, P =0.050; B group χ(2)=4.054, P =0.032) , weighted 6 kHz (A group χ(2)=6.362, P =0.012; B group χ(2)=4.054, P =0.032) , high frequency weighted 4 kHz+6 kHz (A group χ(2)=6.362, P =0.012; B group χ(2)=4.054, P =0.032) than those of speech frequency average value in the same group on oc-cupational noise-induced deafness diagnosis rate, the difference was statistically significant. There was no sig-nificant difference between age groups (χ(2)=2.265, P =0.944) . 4. The better ear's mean value of pure speech fre-quency and the weighted values into different high frequency of working years on each group were compared, working years more than 10 years group was significantly higher than that of average thresholds of each frequen-cy band in 3-5 group ( F =2.271, P =0.001) , 6-10 group ( F =1.563, P =0.046) , the difference was statistically significant. The different high frequency weighted values were higher than those of the mean value of pure speech frequency, and the high frequency weighted 4 kHz+6 kHz had the highest frequency difference, with an average increase of 2.83 dB. 5. The diagnostic rate into weighted different high frequency was higher in the mild, moderate and severe grades than in the pure speech frequency. In the comparison of diagnosis for mild occupational noise-induced deafness, in addition to the weighted 3 kHz high frequency (χ(2)=3.117, P =0.077) had no significant difference, the weighted 4 kHz (χ(2)=10.835, P =0.001) , 6 kHz (χ(2)=9.985, P =0.002) , 3 kHz+4 kHz (χ(2)=6.315, P =0.012) , 3 kHz+6 kHz (χ(2)=6.315, P =0.012) , 4 kHz+6 kHz (χ(2)=9.985, P =0.002) , 3 kHz+4 kHz+6 kHz (χ(2)=7.667, P =0.002) were significantly higher than the diagnosis rate of the mean value of pure speech frequency. There was no significant difference between the two groups in the moderate and se-vere grades ( P >0.05) . Conclusion: Bring into different high frequency hearing threshold weighted value in-creases the diagnostic rate of occupational noise-induced deafness, the weighted 4 kHz, 6 kHz and 4 kHz+ 6 kHz high frequency value affects the result greatly, and the weighted 4 kHz+6 kHz high frequency hearing threshold value is maximum the effect on occupational noise-induced deafness diagnosis.

An inkjet vision measurement technique for high-frequency jetting

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

Kwon, Kye-Si, E-mail: kskwon@sch.ac.kr; Jang, Min-Hyuck; Park, Ha Yeong

2014-06-15

Inkjet technology has been used as manufacturing a tool for printed electronics. To increase the productivity, the jetting frequency needs to be increased. When using high-frequency jetting, the printed pattern quality could be non-uniform since the jetting performance characteristics including the jetting speed and droplet volume could vary significantly with increases in jet frequency. Therefore, high-frequency jetting behavior must be evaluated properly for improvement. However, it is difficult to measure high-frequency jetting behavior using previous vision analysis methods, because subsequent droplets are close or even merged. In this paper, we present vision measurement techniques to evaluate the drop formation ofmore » high-frequency jetting. The proposed method is based on tracking target droplets such that subsequent droplets can be excluded in the image analysis by focusing on the target droplet. Finally, a frequency sweeping method for jetting speed and droplet volume is presented to understand the overall jetting frequency effects on jetting performance.« less

Low-Loss Coupler For Microwave Laser-Diode Modulation

NASA Technical Reports Server (NTRS)

Toda, Minoru

1991-01-01

Elimination of series resistor reduces loss of radio-frequency power. Quarter-wavelength matching section connected to transmission line eliminates need for resistor near laser diode and extends frequency response of system. Concept significantly extends relatively flat frequency response of laser diode or similar component, while simplifying design of its package, increasing amplitude of output signal, and reducing dissipation of heat by eliminating resistance. Phase characteristics approximately linear and any digital information transmitted not significantly altered.

Effect of stride frequency on thermoregulatory responses during endurance running in distance runners.

PubMed

Amano, Tatsuro; Ishitobi, Masaki; Ogura, Yukio; Inoue, Yoshimitsu; Koga, Shunsaku; Nishiyasu, Takeshi; Kondo, Narihiko

2016-10-01

Changing stride frequency may influence oxygen uptake and heart rate during running as a function of running economy and central command. This study investigated the influence of stride frequency manipulation on thermoregulatory responses during endurance running. Seven healthy endurance runners ran on a treadmill at a velocity of 15km/h for 60min in a controlled environmental chamber (ambient temperature 27°C and relative humidity 50%), and stride frequency was manipulated. Stride frequency was intermittently manipulated by increasing and decreasing frequency by 10% from the pre-determined preferred frequency. These periods of increase or decrease were separated by free frequency running in the order of free stride frequency, stride frequency manipulation (increase or decrease), free stride frequency, and stride frequency manipulation (increase or decrease) for 15min each. The increased and decreased stride frequencies were 110% and 91% of the free running frequency, respectively (196±6, 162±5, and 178±5steps/min, respectively, P<0.01). Compared to the control, stride frequency manipulation did not affect rectal temperature, heart rate, or the rate of perceived exhaustion during running. Whole-body sweat loss increased significantly when stride frequency was manipulated (1.48±0.11 and 1.57±0.11kg for control and manipulated stride frequencies, respectively, P<0.05), but stride frequency had a small effect on sweat loss overall (Cohen's d=0.31). A higher mean skin temperature was also observed under mixed frequency conditions compared to that in the control (P<0.05). While the precise mechanisms underlying these changes remain unknown (e.g. running economy or central command), our results suggest that manipulation of stride frequency does not have a large effect on sweat loss or other physiological variables, but does increase mean skin temperature during endurance running. Copyright © 2016. Published by Elsevier Ltd.

Comparison of electroacupuncture frequency-related effects on heart rate variability in healthy volunteers: a randomized clinical trial.

PubMed

Lee, Jong-Ho; Kim, Kyu-Hyeong; Hong, Jin-Woo; Lee, Won-Chul; Koo, Sungtae

2011-06-01

This study aimed to compare the effects of high frequency electroacupuncture (EA) and low-frequency EA on the autonomic nervous system by using a heart rate variability measuring device in normal individuals. Fourteen participants were recruited and each participated in the high-frequency and low-frequency sessions (crossover design). The order of sessions was randomized and the interval between the two sessions was over 2 weeks. Participants received needle insertion with 120-Hz stimulation during the high-frequency session (high-frequency EA group), and with 2-Hz stimulation during the low-frequency session (low-frequency EA group). Acupuncture needles were directly inserted perpendicularly to LI 4 and LI 11 acupoints followed by delivery of electric pulses to these points for 15 minutes. Heart rate variability was measured 5 minutes before and after EA stimulation by a heart rate variability measuring system. We found a significant increase in the standard deviation of the normal-to-normal interval in the high-frequency EA group, with no change in the low-frequency EA group. Both the high-frequency and low-frequency EA groups showed no significant differences in other parameters including high-frequency power, low-frequency power, and the ratio of low-frequency power to high-frequency power. Based on these findings, we concluded that high-frequency EA stimulation is more effective than low-frequency EA stimulation in increasing autonomic nervous activity and there is no difference between the two EA frequencies in enhancing sympathovagal balance. Copyright © 2011 Korean Pharmacopuncture Institute. Published by .. All rights reserved.

Morphological Simulation of Phase Separation Coupled Oscillation Shear and Varying Temperature Fields

NASA Astrophysics Data System (ADS)

Wang, Heping; Li, Xiaoguang; Lin, Kejun; Geng, Xingguo

2018-05-01

This paper explores the effect of the shear frequency and Prandtl number ( Pr) on the procedure and pattern formation of phase separation in symmetric and asymmetric systems. For the symmetric system, the periodic shear significantly prolongs the spinodal decomposition stage and enlarges the separated domain in domain growth stage. By adjusting the Pr and shear frequency, the number and orientation of separated steady layer structures can be controlled during domain stretch stage. The numerical results indicate that the increase in Pr and decrease in the shear frequency can significantly increase in the layer number of the lamellar structure, which relates to the decrease in domain size. Furthermore, the lamellar orientation parallel to the shear direction is altered into that perpendicular to the shear direction by further increasing the shear frequency, and also similar results for larger systems. For asymmetric system, the quantitative analysis shows that the decrease in the shear frequency enlarges the size of separated minority phases. These numerical results provide guidance for setting the optimum condition for the phase separation under periodic shear and slow cooling.

Comparing performance of three oscillating positive expiratory pressure devices at similar amplitude and frequencies of oscillations on displacement of mucus inside trachea during cough.

PubMed

Ragavan, Anpalaki J

2012-03-13

Performance of Flutter® (Axcan Scandipharm Inc, Birmingham, AL), Acapella® (Smiths Medicals Inc, Rockland, MA) and Quake® (Thayer Medical, Tucson, AZ) were compared at similar frequencies and amplitudes of oscillations at nine angles of the device in clearing simulated mucus inside a tracheal model (trachea) oriented at three angles with or without simulated constrictions in airway upstream of trachea. Displacement of 0.4mL of simulated mucus prepared with viscoelastic properties similar to healthy individuals (syrup-like) or patients with COPD (gel-like) using locust bean gum(LBG) solution (0.38g LBG in 100mL water) cross-linked with 3mL or 12mL borax solution (0.02 molar), respectively were measured inside trachea during coughs of 300ms at low cough velocity (15±0.5m/s) generated using a computer controlled solenoid valve. Oscillations were superimposed on cough by connecting the oscillator device to the outlet of the trachea. Frequency and amplitude of oscillations generated by Quake and Acapella and resulting mucus displacement were independent of angle of oscillator, while amplitude of oscillations and resulting mucus displacement generated by Flutter, increased up to 30o upward and 20o downward angles of Flutter from horizontal but decreased significantly thereafter. Displacement with Quake increased significantly with frequencies of oscillations up to 25 Hz and decreased thereafter but increased with amplitudes of oscillations up to 22±4.7 m/s. Quake showed significantly larger displacements than Flutter and Acapella at equal frequencies and amplitudes (p<0.05). Displacements were significantly larger with trachea positioned 30o upwards than horizontal or 20o downwards (p<0.0001). Displacement was the greatest for gel-like mucus than syrup-like (p<0.0001). Airway constrictions upstream resulted in enhanced displacement of mucus (p<0.0001). Mucus clearance can be significantly enhanced by coughing through oscillating positive expiratory devices that generate high amplitude oscillations at moderate frequencies, increasing frontal depths of mucus facing airflow and slightly increasing resistance to airflow in airways in COPD patients.

Musicians Are Better than Non-musicians in Frequency Change Detection: Behavioral and Electrophysiological Evidence

PubMed Central

Liang, Chun; Earl, Brian; Thompson, Ivy; Whitaker, Kayla; Cahn, Steven; Xiang, Jing; Fu, Qian-Jie; Zhang, Fawen

2016-01-01

Objective: The objectives of this study were: (1) to determine if musicians have a better ability to detect frequency changes under quiet and noisy conditions; (2) to use the acoustic change complex (ACC), a type of electroencephalographic (EEG) response, to understand the neural substrates of musician vs. non-musician difference in frequency change detection abilities. Methods: Twenty-four young normal hearing listeners (12 musicians and 12 non-musicians) participated. All participants underwent psychoacoustic frequency detection tests with three types of stimuli: tones (base frequency at 160 Hz) containing frequency changes (Stim 1), tones containing frequency changes masked by low-level noise (Stim 2), and tones containing frequency changes masked by high-level noise (Stim 3). The EEG data were recorded using tones (base frequency at 160 and 1200 Hz, respectively) containing different magnitudes of frequency changes (0, 5, and 50% changes, respectively). The late-latency evoked potential evoked by the onset of the tones (onset LAEP or N1-P2 complex) and that evoked by the frequency change contained in the tone (the acoustic change complex or ACC or N1′-P2′ complex) were analyzed. Results: Musicians significantly outperformed non-musicians in all stimulus conditions. The ACC and onset LAEP showed similarities and differences. Increasing the magnitude of frequency change resulted in increased ACC amplitudes. ACC measures were found to be significantly different between musicians (larger P2′ amplitude) and non-musicians for the base frequency of 160 Hz but not 1200 Hz. Although the peak amplitude in the onset LAEP appeared to be larger and latency shorter in musicians than in non-musicians, the difference did not reach statistical significance. The amplitude of the onset LAEP is significantly correlated with that of the ACC for the base frequency of 160 Hz. Conclusion: The present study demonstrated that musicians do perform better than non-musicians in detecting frequency changes in quiet and noisy conditions. The ACC and onset LAEP may involve different but overlapping neural mechanisms. Significance: This is the first study using the ACC to examine music-training effects. The ACC measures provide an objective tool for documenting musical training effects on frequency detection. PMID:27826221

Somatic cell mutations at the glycophorin A locus in erythrocytes of atomic bomb survivors: Implications for radiation carcinogenesis

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

Kyoizumi, Seishi; Akiyama, Mitoshi; Tanabe, Kazumi

To clarify the relationship between somatic cell mutations and radiation exposure, the frequency of hemizygous mutant erythrocytes at the glycophorin A (GPA) locus was measured by flow cytometry for 1,226 heterozygous atomic bomb (A-bomb) survivors in HIroshima and Nagasaki. For statistical analysis, both GPA mutant frequency and radiation dose were log-transformed to normalize skewed distributions of these variables. The GPA mutant frequency increased slightly but significantly with age at testing and with the number of cigarettes smoked. Also, mutant frequency was significantly higher in males than in females even with adjustment for smoking and was higher to Hiroshima than inmore » Nagasaki. These characteristics of background GPA mutant frequency are qualitatively similar to those of background solid cancer incidence or mortality obtained from previous epidemiological studies of survivors. An analysis of the mutant frequency dose response using a descriptive model showed that the doubling dose is about 1.20 Sv [95% confidence interval (CI): 0.95-1.56], whereas the minimum dose for detecting a significant increase in mutant frequency is about 0.24 Sv (95% CI: 0.041-0.51). No significant effects of sex, city or age at the time of exposure on the dose response were detected. Interestingly, the doubling dose of the GPA mutant frequency was similar to that of solid cancer incidence in A-bomb survivors. This observation is in line with the hypothesis that radiation-induced somatic cell mutations are the major cause of excess cancer risk after radiation. 49 refs., 6 figs., 2 tabs.« less

Changes in the highest frequency of breath sounds without wheezing during methacholine inhalation challenge in children.

PubMed

Habukawa, Chizu; Murakami, Katsumi; Mochizuki, Hiroyuki; Takami, Satoru; Muramatsu, Reiko; Tadaki, Hiromi; Hagiwara, Satomi; Mizuno, Takahisa; Arakawa, Hirokazu; Nagasaka, Yukio

2010-04-01

It is difficult for clinicians to identify changes in breath sounds caused by bronchoconstriction when wheezing is not audible. A breath sound analyser can identify changes in the frequency of breath sounds caused by bronchoconstriction. The present study aimed to identify the changes in the frequency of breath sounds during bronchoconstriction and bronchodilatation using a breath sound analyser. Thirty-six children (8.2 +/- 3.7 years; males : females, 22 : 14) underwent spirometry, methacholine inhalation challenge and breath sound analysis. Methacholine inhalation challenge was performed and baseline respiratory resistance, minimum dose of methacholine (bronchial sensitivity) and speed of bronchoconstriction in response to methacholine (Sm: bronchial reactivity) were calculated. The highest frequency of inspiratory breath sounds (HFI), the highest frequency of expiratory breath sounds (HFE) and the percentage change in HFI and HFE were determined. The HFI and HFE were compared before methacholine inhalation (pre-HFI and pre-HFE), when respiratory resistance reached double the baseline value (max HFI and max HFE), and after bronchodilator inhalation (post-HFI and post-HFE). Breath sounds increased during methacholine-induced bronchoconstriction. Max HFI was significantly greater than pre-HFI (P < 0.001), and decreased to the basal level after bronchodilator inhalation. Post-HFI was significantly lower than max HFI (P < 0.001). HFI and HFE were also significantly changed (P < 0.001). The percentage change in HFI showed a significant correlation with the speed of bronchoconstriction in response to methacholine (P = 0.007). Methacholine-induced bronchoconstriction significantly increased HFI, and the increase in HFI was correlated with bronchial reactivity.

Periodontal disease in Hispanic Americans with type 2 diabetes.

PubMed

Novak, M John; Potter, Richard M; Blodgett, Janet; Ebersole, Jeffrey L

2008-04-01

Diabetes is a major risk factor for the development of periodontal disease in certain populations. The prevalence of type 2 diabetes is increased in Hispanic Americans, but its impact on the extent and severity of periodontal disease in this population has not been determined. Sixty-three Hispanic Americans, aged 33 to 72 years, from South Texas were grouped based on the presence or absence of type 2 diabetes. Past medical histories, including smoking, were obtained. Periodontal status was evaluated by measuring probing depth (PD), clinical attachment level (CAL), plaque, bleeding on probing, visual gingival inflammation, and calculus. Type 2 diabetes was associated frequently with major medical complications in this population. Diabetes was associated with significantly more calculus formation and tooth loss and an increased extent and severity of periodontitis. Subjects with diabetes had nearly three times the mean CAL and frequency of PD >6 mm than subjects without diabetes and nearly twice the frequency of moderate to advanced attachment loss (> or =3 mm). Smoking and diabetes had significant independent effects on mean CAL and the frequency of deep pockets. Diabetes and smoking combined were associated with a significantly higher frequency of sites with CAL > or =3 mm compared to healthy non-smokers, healthy smokers, and non-smokers with diabetes. Hispanic Americans with type 2 diabetes had more supra- and subgingival calculus, an increased extent and severity of periodontal destruction, and an increased frequency of tooth loss due to periodontitis. An additive/synergistic contribution of type 2 diabetes and smoking for increasing the extent of periodontal disease was observed.

Social stress induces changes in urinary bladder function, bladder NGF content, and generalized bladder inflammation in mice

PubMed Central

Peterson, Abbey; Erickson, Cuixia Shi; Nelson, Mark T.; Vizzard, Margaret A.

2014-01-01

Social stress may play a role in urinary bladder dysfunction in humans, but the underlying mechanisms are unknown. In the present study, we explored changes in bladder function caused by social stress using mouse models of stress and increasing stress. In the stress paradigm, individual submissive FVB mice were exposed to C57BL/6 aggressor mice directly/indirectly for 1 h/day for 2 or 4 wk. Increased stress was induced by continuous, direct/indirect exposure of FVB mice to aggressor mice for 2 wk. Stressed FVB mice exhibited nonvoiding bladder contractions and a decrease in both micturition interval (increased voiding frequency) and bladder capacity compared with control animals. ELISAs demonstrated a significant increase in histamine protein expression with no change in nerve growth factor protein expression in the urinary bladder compared with controls. Unlike stressed mice, mice exposed to an increased stress paradigm exhibited increased bladder capacities and intermicturition intervals (decreased voiding frequency). Both histamine and nerve growth factor protein expression were significantly increased with increased stress compared with control bladders. The change in bladder function from increased voiding frequency to decreased voiding frequency with increased stress intensity suggests that changes in social stress-induced urinary bladder dysfunction are context and duration dependent. In addition, changes in the bladder inflammatory milieu with social stress may be important contributors to changes in urinary bladder function. PMID:25100077

Acute effects on cardiovascular oscillations during controlled slow yogic breathing.

PubMed

Bhagat, Om Lata; Kharya, Chhaya; Jaryal, Ashok; Deepak, Kishore Kumar

2017-04-01

Breathing exercises are believed to modulate the cardiovascular oscillations in the body. To assess the validity of the assumption and understand the underlying mechanism, the key autonomic regulatory parameters such as heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were recorded during controlled slow yogic breathing. Alternate nostril breathing (ANB) was selected as the yogic manoeuvre. Twelve healthy volunteers (age 30±3.8 yr) participated in the study. ANB was performed at a breathing frequency of 5 breaths per minute (bpm). In each participant, the electrocardiogram, respiratory movements, beat-to-beat BP and end-tidal carbon dioxide were recorded for five minutes each: before, during and after ANB. The records were analyzed for HRV, BPV and BRS. During ANB, HRV analysis showed significant increase in the standard deviation of all NN intervals, low-frequency (LF) component, LF/HF (low frequency/high frequency) ratio and significant decrease in the HF component. BPV analysis showed a significant increase in total power in systolic BPV (SBPV), diastolic BPV (DBPV) and mean BPV. BRS analysis showed a significant increase in the total number of sequences in SBPV and DBPV and significant augmentation of α-LF and reduction in α-HF. The power spectrum showed a dominant peak in HRV at 0.08 Hz (LF component) similar to the respiratory frequency. The acute short-term change in circulatory control system declined immediately after the cessation of slow yogic breathing (ANB) and remained elevated in post-ANB stage as compared to the pre-ANB. Significant increase in cardiovascular oscillations and baroreflex recruitments during-ANB suggested a dynamic interaction between respiratory and cardiovascular system. Enhanced phasic relationship with some delay indicated the complexity of the system. It indicated that respiratory and cardiovascular oscillations were coupled through multiple regulatory mechanisms, such as mechanical coupling, baroreflex and central cardiovascular control.

An experimental study for determining human discomfort response to roll vibration

NASA Technical Reports Server (NTRS)

Leatherwood, J. D.; Dempsey, T. K.; Clevenson, S. A.

1976-01-01

An experimental study using a passenger ride quality apparatus (PRQA) was conducted to determine the subjective reactions of passengers to roll vibrations. The data obtained illustrate the effect upon human comfort of several roll-vibration parameters: namely, roll acceleration level, roll frequency, and seat location (i.e., distance from axis of rotation). Results of an analysis of variance indicated that seat location had no effect on discomfort ratings of roll vibrations. The effect of roll acceleration level was significant, and discomfort ratings increased markedly with increasing roll acceleration level at all roll frequencies investigated. Of particular interest, is the fact that the relationship between discomfort ratings and roll acceleration level was linear in nature. The effect of roll frequency also was significant as was the interaction between roll acceleration level and roll frequency.

Incidence of swallowing during exercise in horses with dorsal displacement of the soft palate.

PubMed

Pigott, J H; Ducharme, N G; Mitchell, L M; Soderholm, L V; Cheetham, J

2010-11-01

The relationship between dorsal displacement of the soft palate (DDSP) and swallowing is unclear. To quantify the relationship between DDSP and swallowing in horses at exercise. The frequency of swallowing increases immediately prior to DDSP in horses at exercise. Videoendoscopic and upper airway pressure data were collated from horses with a definitive diagnosis of DDSP at exercise. Horses with no upper airway abnormalities were matched by age, breed and sex and used as controls. Sixty-nine horses were identified with a definitive diagnosis of DDSP during the study interval. Airway pressure data were available for 42 horses. The majority of horses displaced at high exercising speeds while accelerating; a smaller number displaced during deceleration after peak speed had been reached. Horses swallowed significantly more frequently in the 1 min immediately preceding DDSP than in the control horses at equivalent speeds. DDSP at exercise results in a significant increase in tracheal expiratory pressure, a significant decrease in pharyngeal expiratory pressure and a significantly less negative pharyngeal inspiratory pressure compared to matched controls and compared to the pressures during the 1 min interval prior to DDSP. There was no significant difference between any measure of airway pressure before or after a swallow when examined at each time interval in the DDSP population. The frequency of swallowing decreases with increasing speed in normal horses. In contrast, the frequency of swallowing increases immediately prior to onset of DDSP. This is not a result of pharyngeal and tracheal pressure changes. The increased frequency of swallowing observed prior to DDSP may be related to the aetiology of the disease. © 2010 EVJ Ltd.

Effects of cigarette smoking on cardiac autonomic function during dynamic exercise.

PubMed

Mendonca, Goncalo V; Pereira, Fernando D; Fernhall, Bo

2011-06-01

The purpose of this study was to investigate the acute effect of cigarette smoking on cardiac autonomic function in young adult smokers during dynamic exercise. Fourteen healthy young smokers (21.4 ± 3.4 years) performed peak and submaximal exercise protocols under control and smoking conditions. Resting and submaximal beat-to-beat R-R series were recorded and spectrally decomposed using the fast Fourier transformation. Smoking resulted in a significant decrease in work time, VO(2peak) and peak O(2) pulse (P < 0.05). Heart rate increased at rest and during submaximal exercise after smoking (P < 0.05). The raw high frequency and low frequency power were significantly reduced by smoking, both at rest and during exercise (P < 0.05). The low to high frequency ratio was higher after smoking (P < 0.05). The normalised low frequency power was also significantly increased by smoking, but only at rest (P < 0.05). These data demonstrate that the tachycardic effect elicited by smoking is accompanied by acute changes in heart rate spectral components both at rest and during exercise. Therefore, the cardiac autonomic control is altered by smoking not only at rest, but also during exercise, resulting in reduced vagal modulation and increased sympathetic dominance.

Acute nonlymphocytic leukemia and residential exposure to power frequency magnetic fields

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

Severson, R.K.

1986-01-01

A population-based case-control study of adult acute nonlymphocytic leukemia (ANLL) and residential exposure to power frequency magnetic fields was conducted in King, Pierce and Snohomish Counties in Washington state. Of 164 cases who were diagnosed from January 1, 1981 through December 31, 1984, 114 were interviewed. Controls were selected from the study area on the basis of random digit dialing and frequency matched to the cases by age and sex. Analyses were undertaken to evaluate whether exposure to high levels of power frequency magnetic fields in the residence were associated with an increased risk of ANLL. Neither the directly measuredmore » magnetic fields nor the surrogate values based on the wiring configurations were associated with ANLL. Additional analyses suggested that persons with prior allergies were at decreased risk of acute myelocytic leukemia (AML). Also, persons with prior autoimmune diseases were at increased risk of AML. The increase in AML risk in rheumatoid arthritics was of borderline statistical significance. Finally, cigarette smoking was associated with an increased risk of AML. The risk of AML increased significantly with the number of years of cigarette smoking.« less

Callback response of dugongs to conspecific chirp playbacks.

PubMed

Ichikawa, Kotaro; Akamatsu, Tomonari; Shinke, Tomio; Adulyanukosol, Kanjana; Arai, Nobuaki

2011-06-01

Dugongs (Dugong dugon) produce bird-like calls such as chirps and trills. The vocal responses of dugongs to playbacks of several acoustic stimuli were investigated. Animals were exposed to four different playback stimuli: a recorded chirp from a wild dugong, a synthesized down-sweep sound, a synthesized constant-frequency sound, and silence. Wild dugongs vocalized more frequently after playback of broadcast chirps than that after constant-frequency sounds or silence. The down-sweep sound also elicited more vocal responses than did silence. No significant difference was found between the broadcast chirps and the down-sweep sound. The ratio of wild dugong chirps to all calls and the dominant frequencies of the wild dugong calls were significantly higher during playbacks of broadcast chirps, down-sweep sounds, and constant-frequency sounds than during those of silence. The source level and duration of dugong chirps increased significantly as signaling distance increased. No significant correlation was found between signaling distance and the source level of trills. These results show that dugongs vocalize to playbacks of frequency-modulated signals and suggest that the source level of dugong chirps may be manipulated to compensate for transmission loss between the source and receiver. This study provides the first behavioral observations revealing the function of dugong chirps. © 2011 Acoustical Society of America

Masking of low-frequency signals by high-frequency, high-level narrow bands of noisea

PubMed Central

Patra, Harisadhan; Roup, Christina M.; Feth, Lawrence L.

2011-01-01

Low-frequency masking by intense high-frequency noise bands, referred to as remote masking (RM), was the first evidence to challenge energy-detection models of signal detection. Its underlying mechanisms remain unknown. RM was measured in five normal-hearing young-adults at 250, 350, 500, and 700 Hz using equal-power, spectrally matched random-phase noise (RPN) and low-noise noise (LNN) narrowband maskers. RM was also measured using equal-power, two-tone complex (TC2) and eight-tone complex (TC8). Maskers were centered at 3000 Hz with one or two equivalent rectangular bandwidths (ERBs). Masker levels varied from 80 to 95 dB sound pressure level in 5 dB steps. LNN produced negligible masking for all conditions. An increase in bandwidth in RPN yielded greater masking over a wider frequency region. Masking for TC2 was limited to 350 and 700 Hz for one ERB but shifted to only 700 Hz for two ERBs. A spread of masking to 500 and 700 Hz was observed for TC8 when the bandwidth was increased from one to two ERBs. Results suggest that high-frequency noise bands at high levels could generate significant low-frequency masking. It is possible that listeners experience significant RM due to the amplification of various competing noises that might have significant implications for speech perception in noise. PMID:21361445

Application of chemometrics to assess the influence of ultrasound frequency, Lactobacillus sakei culture and drying on beef jerky manufacture: Impact on amino acid profile, organic acids, texture and colour.

PubMed

Shikha Ojha, K; Granato, Daniel; Rajuria, Gaurav; Barba, Francisco J; Kerry, Joseph P; Tiwari, Brijesh K

2018-01-15

The effects of ultrasound (US) frequency, addition of Lactobacillus sakei culture and drying time on key nutritional (protein, amino acids, and organic acids) and physicochemical properties (texture and colour) of cultured and uncultured beef jerky were evaluated. Cultured and uncultured jerky samples were subjected to US frequencies of 25kHz, 33kHz and 45kHz for 30min prior to marination and drying. Principal component analysis demonstrated a significant effect of beef jerky processing conditions on physicochemical properties. Taurine content of jerky samples was found to increase with an increase in ultrasonic frequencies for cultured samples. No significant changes in colour values were observed for ultrasound pre-treated and control samples. Interactive effects of culture treatment, drying and ultrasonic frequency were observed. This study demonstrates that the nutritional profile of beef jerky can be improved through the incorporation of L. sakei. Copyright © 2017 Elsevier Ltd. All rights reserved.

Linear response of mutans streptococci to increasing frequency of xylitol chewing gum use: a randomized controlled trial [ISRCTN43479664

PubMed Central

Ly, Kiet A; Milgrom, Peter; Roberts, Marilyn C; Yamaguchi, David K; Rothen, Marilynn; Mueller, Greg

2006-01-01

Background Xylitol is a naturally occurring sugar substitute that has been shown to reduce the level of mutans streptococci in plaque and saliva and to reduce tooth decay. It has been suggested that the degree of reduction is dependent on both the amount and the frequency of xylitol consumption. For xylitol to be successfully and cost-effectively used in public health prevention strategies dosing and frequency guidelines should be established. This study determined the reduction in mutans streptococci levels in plaque and unstimulated saliva to increasing frequency of xylitol gum use at a fixed total daily dose of 10.32 g over five weeks. Methods Participants (n = 132) were randomized to either active groups (10.32 g xylitol/day) or a placebo control (9.828 g sorbitol and 0.7 g maltitol/day). All groups chewed 12 pieces of gum per day. The control group chewed 4 times/day and active groups chewed xylitol gum at a frequency of 2 times/day, 3 times/day, or 4 times/day. The 12 gum pieces were evenly divided into the frequency assigned to each group. Plaque and unstimulated saliva samples were taken at baseline and five-weeks and were cultured on modified Mitis Salivarius agar for mutans streptococci enumeration. Results There were no significant differences in mutans streptococci level among the groups at baseline. At five-weeks, mutans streptococci levels in plaque and unstimulated saliva showed a linear reduction with increasing frequency of xylitol chewing gum use at the constant daily dose. Although the difference observed for the group that chewed xylitol 2 times/day was consistent with the linear model, the difference was not significant. Conclusion There was a linear reduction in mutans streptococci levels in plaque and saliva with increasing frequency of xylitol gum use at a constant daily dose. Reduction at a consumption frequency of 2 times per day was small and consistent with the linear-response line but was not statistically significant. PMID:16556326

A controlled trial of reduced meal frequency without caloric restriction in healthy, normal-weight, middle-aged adults123

PubMed Central

Stote, Kim S; Baer, David J; Spears, Karen; Paul, David R; Harris, G Keith; Rumpler, William V; Strycula, Pilar; Najjar, Samer S; Ferrucci, Luigi; Ingram, Donald K; Longo, Dan L; Mattson, Mark P

2009-01-01

Background Although consumption of 3 meals/d is the most common pattern of eating in industrialized countries, a scientific rationale for this meal frequency with respect to optimal health is lacking. A diet with less meal frequency can improve the health and extend the lifespan of laboratory animals, but its effect on humans has never been tested. Objective A pilot study was conducted to establish the effects of a reduced-meal-frequency diet on health indicators in healthy, normal-weight adults. Design The study was a randomized crossover design with two 8-wk treatment periods. During the treatment periods, subjects consumed all of the calories needed for weight maintenance in either 3 meals/d or 1 meal/d. Results Subjects who completed the study maintained their body weight within 2 kg of their initial weight throughout the 6-mo period. There were no significant effects of meal frequency on heart rate, body temperature, or most of the blood variables measured. However, when consuming 1 meal/d, subjects had a significant increase in hunger; a significant modification of body composition, including reductions in fat mass; significant increases in blood pressure and in total, LDL-, and HDL-cholesterol concentrations; and a significant decrease in concentrations of cortisol. Conclusions Normal-weight subjects are able to comply with a 1 meal/d diet. When meal frequency is decreased without a reduction in overall calorie intake, modest changes occur in body composition, some cardiovascular disease risk factors, and hematologic variables. Diurnal variations may affect outcomes. PMID:17413096

Electro-acupuncture stimulation acts on the basal ganglia output pathway to ameliorate motor impairment in Parkinsonian model rats.

PubMed

Jia, Jun; Li, Bo; Sun, Zuo-Li; Yu, Fen; Wang, Xuan; Wang, Xiao-Min

2010-04-01

The role of electro-acupuncture (EA) stimulation on motor symptoms in Parkinson's disease (PD) has not been well studied. In a rat hemiparkinsonian model induced by unilateral transection of the medial forebrain bundle (MFB), EA stimulation improved motor impairment in a frequency-dependent manner. Whereas EA stimulation at a low frequency (2 Hz) had no effect, EA stimulation at a high frequency (100 Hz) significantly improved motor coordination. However, neither low nor high EA stimulation could significantly enhance dopamine levels in the striatum. EA stimulation at 100 Hz normalized the MFB lesion-induced increase in midbrain GABA content, but it had no effect on GABA content in the globus pallidus. These results suggest that high-frequency EA stimulation improves motor impairment in MFB-lesioned rats by increasing GABAergic inhibition in the output structure of the basal ganglia.

The Group Delay and Suppression Pattern of the Cochlear Microphonic Potential Recorded at the Round Window

PubMed Central

He, Wenxuan; Porsov, Edward; Kemp, David; Nuttall, Alfred L.; Ren, Tianying

2012-01-01

Background It is commonly assumed that the cochlear microphonic potential (CM) recorded from the round window (RW) is generated at the cochlear base. Based on this assumption, the low-frequency RW CM has been measured for evaluating the integrity of mechanoelectrical transduction of outer hair cells at the cochlear base and for studying sound propagation inside the cochlea. However, the group delay and the origin of the low-frequency RW CM have not been demonstrated experimentally. Methodology/Principal Findings This study quantified the intra-cochlear group delay of the RW CM by measuring RW CM and vibrations at the stapes and basilar membrane in gerbils. At low sound levels, the RW CM showed a significant group delay and a nonlinear growth at frequencies below 2 kHz. However, at high sound levels or at frequencies above 2 kHz, the RW CM magnitude increased proportionally with sound pressure, and the CM phase in respect to the stapes showed no significant group delay. After the local application of tetrodotoxin the RW CM below 2 kHz became linear and showed a negligible group delay. In contrast to RW CM phase, the BM vibration measured at location ∼2.5 mm from the base showed high sensitivity, sharp tuning, and nonlinearity with a frequency-dependent group delay. At low or intermediate sound levels, low-frequency RW CMs were suppressed by an additional tone near the probe-tone frequency while, at high sound levels, they were partially suppressed only at high frequencies. Conclusions/Significance We conclude that the group delay of the RW CM provides no temporal information on the wave propagation inside the cochlea, and that significant group delay of low-frequency CMs results from the auditory nerve neurophonic potential. Suppression data demonstrate that the generation site of the low-frequency RW CM shifts from apex to base as the probe-tone level increases. PMID:22470560

Effects of frequency compression and frequency transposition on fricative and affricate perception in listeners with normal hearing and mild to moderate hearing loss

PubMed Central

Alexander, Joshua M.; Kopun, Judy G.; Stelmachowicz, Patricia G.

2014-01-01

Summary: Listeners with normal hearing and mild to moderate loss identified fricatives and affricates that were recorded through hearing aids with frequency transposition (FT) or nonlinear frequency compression (NFC). FT significantly degraded performance for both groups. When frequencies up to ~9 kHz were lowered with NFC and with a novel frequency compression algorithm, spectral envelope decimation, performance significantly improved relative to conventional amplification (NFC-off) and was equivalent to wideband speech. Significant differences between most conditions could be largely attributed to an increase or decrease in confusions for /s/ and /z/. Objectives: Stelmachowicz and colleagues have demonstrated that the limited bandwidth associated with conventional hearing aid amplification prevents useful high-frequency speech information from being transmitted. The purpose of this study was to examine the efficacy of two popular frequency-lowering algorithms and one novel algorithm (spectral envelope decimation) in adults with mild-to-moderate sensorineural hearing loss and in normal-hearing controls. Design: Participants listened monaurally through headphones to recordings of nine fricatives and affricates spoken by three women in a vowel-consonant (VC) context. Stimuli were mixed with speech-shaped noise at 10 dB SNR and recorded through a Widex Inteo IN-9 and a Phonak Naída UP V behind-the-ear (BTE) hearing aid. Frequency transposition (FT) is used in the Inteo and nonlinear frequency compression (NFC) used in the Naída. Both devices were programmed to lower frequencies above 4 kHz, but neither device could lower frequencies above 6-7 kHz. Each device was tested under four conditions: frequency lowering deactivated (FT-off and NFC-off), frequency lowering activated (FT and NFC), wideband (WB), and a fourth condition unique to each hearing aid. The WB condition was constructed by mixing recordings from the first condition with high-pass filtered versions of the source stimuli. For the Inteo, the fourth condition consisted of recordings made with the same settings as the first, but with the noise reduction feature activated (FT-off). For the Naída, the fourth condition was the same as the first condition except that source stimuli were pre-processed by a novel frequency compression algorithm, spectral envelope decimation (SED), designed in MATLAB that allowed for a more complete lowering of the 4-10 kHz input band. A follow up experiment with NFC used Phonak’s Naída SP V BTE, which could also lower a greater range of input frequencies. Results: For normal-hearing (NH) and hearing-impaired (HI) listeners, performance with FT was significantly worse compared to the other conditions. Consistent with previous findings, performance for the HI listeners in the WB condition was significantly better than in the FT-off condition. In addition, performance in the SED and WB conditions were both significantly better than the NFC-off condition and the NFC condition with 6 kHz input bandwidth. There were no significant differences between SED and WB, indicating that improvements in fricative identification obtained by increasing bandwidth can also be obtained using this form of frequency compression. Significant differences between most conditions could be largely attributed to an increase or decrease in confusions for the phonemes /s/ and /z/. In the follow up experiment, performance in the NFC condition with 10 kHz input bandwidth was significantly better than NFC-off, replicating the results obtained with SED. Furthermore, listeners who performed poorly with NFC-off tended to show the most improvement with NFC. Conclusions: Improvements in the identification of stimuli chosen to be sensitive to the effects of frequency lowering have been demonstrated using two forms of frequency compression (NFC and SED) in individuals with mild to moderate high-frequency SNHL. However, negative results caution against using FT for this population. Results also indicate that the advantage of an extended bandwidth as reported here and elsewhere applies to the input bandwidth for frequency compression (NFC/SED) when the start frequency is ≥ 4 kHz. PMID:24699702

Effects of alprazolam on cortical activity and tremors in patients with essential tremor.

PubMed

Ibáñez, Jaime; González de la Aleja, Jesús; Gallego, Juan A; Romero, Juan P; Saíz-Díaz, Rosana A; Benito-León, Julián; Rocon, Eduardo

2014-01-01

Essential tremor (ET) is characterised by postural and action tremors with a frequency of 4-12 Hz. Previous studies suggest that the tremor activity originates in the cerebello-thalamocortical pathways. Alprazolam is a short-acting benzodiazepine that attenuates tremors in ET. The mechanisms that mediate the therapeutic action of alprazolam are unknown; however, in healthy subjects, benzodiazepines increase cortical beta activity. In this study, we investigated the effect of alprazolam both on beta and tremor-related cortical activity and on alterations in tremor presentation in ET patients. Therefore, we characterised the dynamics of tremor and cortical activity in ET patients after alprazolam intake. We recorded hand tremors and contralateral cortical activity in four recordings before and after a single dose of alprazolam. We then computed the changes in tremors, cortico-muscular coherence, and cortical activity at the tremor frequency and in the beta band. Alprazolam significantly attenuated tremors (EMG: 76.2 ± 22.68%), decreased cortical activity in the tremor frequency range and increased cortical beta activity in all patients (P<0.05). At the same time, the cortico-muscular coherence at the tremor frequency became non-significant (P<0.05). We also found a significant correlation (r = 0.757, P<0.001) between the reduction in tremor severity and the increased ratio of cortical activity in the beta band to the activity observed in the tremor frequency range. This study provides the first quantitative analysis of tremor reduction following alprazolam intake. We observed that the tremor severity decreased in association with an increased ratio of beta to tremor-related cortical activity. We hypothesise that the increase in cortical beta activity may act as a blocking mechanism and may dampen the pathological oscillatory activity, which in turn attenuates the observed tremor.

Bone fractures as indicators of intentional violence in the eastern Adriatic from the antique to the late medieval period (2nd-16th century AD).

PubMed

Slaus, Mario; Novak, Mario; Bedić, Zeljka; Strinović, Davor

2012-09-01

To test the historically documented hypothesis of a general increase in deliberate violence in the eastern Adriatic from the antique (AN; 2nd-6th c.) through the early medieval (EM; 7th-11th c.) to the late-medieval period (LM; 12th-16th c.), an analysis of the frequency and patterning of bone trauma was conducted in three skeletal series from these time periods. A total of 1,125 adult skeletons-346 from the AN, 313 from the EM, and 466 from the LM series-were analyzed. To differentiate between intentional violence and accidental injuries, data for trauma frequencies were collected for the complete skeleton, individual long bones, and the craniofacial region as well as by type of injury (perimortem vs. antemortem). The results of our analyses show a significant temporal increase in total fracture frequencies when calculated by skeleton as well as of individuals exhibiting one skeletal indicator of deliberate violence (sharp force lesions, craniofacial injuries, "parry" fractures, or perimortem trauma). No significant temporal increases were, however, noted in the frequencies of craniofacial trauma, "parry" fractures, perimortem injuries, or of individuals exhibiting multiple skeletal indicators of intentional violence. Cumulatively, these data suggest that the temporal increase in total fracture frequencies recorded in the eastern Adriatic was caused by a combination of factors that included not only an increase of intentional violence but also a significant change in lifestyle that accompanied the transition from a relatively affluent AN urban lifestyle to a more primitive rural medieval way of life. Copyright © 2012 Wiley Periodicals, Inc.

Acute effects of Finnish sauna and cold-water immersion on haemodynamic variables and autonomic nervous system activity in patients with heart failure.

PubMed

Radtke, Thomas; Poerschke, Daniel; Wilhelm, Matthias; Trachsel, Lukas D; Tschanz, Hansueli; Matter, Friederike; Jauslin, Daniel; Saner, Hugo; Schmid, Jean-Paul

2016-04-01

The haemodynamic response to Finnish sauna and subsequent cold-water immersion in heart failure patients is unknown. Haemodynamic response to two consecutive Finnish sauna (80℃) exposures, followed by a final head-out cold-water immersion (12℃) was measured in 37 male participants: chronic heart failure (n = 12, 61.8 ± 9.2 years), coronary artery disease (n = 13, 61.2 ± 10.6 years) and control subjects (n = 12, 60.9 ± 8.9 years). Cardiac output was measured non-invasively with an inert gas rebreathing method prior to and immediately after the first sauna exposure and after cold-water immersion, respectively. Blood pressure was measured before, twice during and after sauna. The autonomic nervous system was assessed by power spectral analysis of heart rate variability. Total power, low-frequency and high-frequency components were evaluated. The low frequency/high frequency ratio was used as a marker of sympathovagal balance. Sauna and cold-water immersion were well tolerated by all subjects. Cardiac output and heart rate significantly increased in all groups after sauna and cold-water immersion (p < 0.05), except for coronary artery disease patients after sauna exposure. Systolic blood pressure during sauna decreased significantly in all groups with a nadir after 6 min (all p < 0.05). Cold-water immersion significantly increased systolic blood pressure in all groups (p < 0.05). No change in the low/high frequency ratio was found in chronic heart failure patients. In coronary artery disease patients and controls a prolonged increase in low frequency/high frequency ratio was observed after the first sauna exposure. Acute exposure to Finnish sauna and cold-water immersion causes haemodynamic alterations in chronic heart failure patients similarly to control subjects and in particular did not provoke an excessive increase in adrenergic activity or complex arrhythmias. © The European Society of Cardiology 2015.

Very low frequency oscillations in the power spectra of heart rate variability during dry supine immersion and exposure to non-hypoxic hypobaria.

PubMed

Tripathi, K K

2011-06-01

The origin of very low frequency (VLF) oscillations in the power spectra of heart rate variability (HRV) is controversial with possible mechanisms involving thermoregulation and/or renin-angiotensin-aldosterone system. Recently, a major contribution from vagal influences has been suggested. The present study investigated the behaviour of VLF (0.004-0.040 Hz) components of HRV power spectra in a group of healthy male volunteers during their exposure to (1) dry, supine, immersion in thermo-neutral water for 6 h (n = 7) and (2) non-hypoxic hypobaria (breathing 40-60% oxygen at 15,000' simulated in a decompression chamber) for 5 h (n = 15). The two manoeuvres are established to increase vagal outflow. During both the manoeuvres, all the frequency domain indices of HRV exhibited a significant increase. Increase in HRV was much more than that in the R-R interval. At 6 h of immersion, the R-R interval increased by ∼ 15% but the total power increased ∼ fourfold. Similarly, at 5 h of exposure to hypobaria, total power increased ∼ twofold with a very modest increase in an R-R of ∼ 9%. Increase in spectral power was appreciable even after normalization with mean R-R(2). Increase in VLF during immersion was more than reported during enalaprilat blockade of angiotensin convertase enzyme. Plasma renin activity did not vary during hypobaria. There was a significant increase in pNN50, an established marker of cardiac vagal activity. Centre frequencies of the spectra and slope (β) of the relation between log(PSD) and log(frequency) did not change. Results were supportive of the notion that the parasympathetic system is pre-potent to influence slower (than respiratory) frequency components in HRV spectrum. Additionally, such an effect was without a change in the time constant of effector responses or pacemaker frequencies of VLF and LF periodicities and HRV was not a simple linear surrogate for cardiac vagal effects. An invariance of spectral exponent (β) ruled out contamination of VLF and LF spectra from fractal power as an alternate explanation.

Observed increase in extreme daily rainfall in the French Mediterranean

NASA Astrophysics Data System (ADS)

Ribes, Aurélien; Thao, Soulivanh; Vautard, Robert; Dubuisson, Brigitte; Somot, Samuel; Colin, Jeanne; Planton, Serge; Soubeyroux, Jean-Michel

2018-04-01

We examine long-term trends in the historical record of extreme precipitation events occurring over the French Mediterranean area. Extreme events are considered in terms of their intensity, frequency, extent and precipitated volume. Changes in intensity are analysed via an original statistical approach where the annual maximum rainfall amounts observed at each measurement station are aggregated into a univariate time-series according to their dependence. The mean intensity increase is significant and estimated at + 22% (+ 7 to + 39% at the 90% confidence level) over the 1961-2015 period. Given the observed warming over the considered area, this increase is consistent with a rate of about one to three times that implied by the Clausius-Clapeyron relationship. Changes in frequency and other spatial features are investigated through a Generalised Linear Model. Changes in frequency for events exceeding high thresholds (about 200 mm in 1 day) are found to be significant, typically near a doubling of the frequency, but with large uncertainties in this change ratio. The area affected by severe events and the water volume precipitated during those events also exhibit significant trends, with an increase by a factor of about 4 for a 200 mm threshold, again with large uncertainties. All diagnoses consistently point toward an intensification of the most extreme events over the last decades. We argue that it is difficult to explain the diagnosed trends without invoking the human influence on climate.

Physico-chemical factors influencing spore germination in cyanobacterium Fischerella muscicola.

PubMed

Mishra, Biranchi N; Kaushik, Manish S; Abraham, Gerard; Singh, Pawan K

2018-06-19

Spore (akinete) formation in the heterocystous and branched filamentous cyanobacterium Fischerella muscicola involves a significant increase in cell size and formation of several endospores in each of the cells. In present study, the physico-chemical factors (pH, light sources, nutrient deficiency, nitrogen sources, carbon sources, and growth hormones) affecting the germination of spores of F. muscicola were examined. Increase in spore germination frequency was detected above pH 8 with maximum germination (46.04%) recorded at pH 9, whereas a significant decrease in germination was observed at pH 6 when compared to control (pH 7.6). Spore germination was not observed at pH 5. Among light sources germination frequency followed the following order, that is, red light (39.9%) > white light (33.8%) > yellow light (3.4%) > green light (1.3%) whereas germination did not take place in dark and blue light. Ammonium chloride (NH 4 Cl) supported maximum (99.5%) germination frequency followed by calcium nitrate (Ca(NO 3 ) 2 ), potassium nitrate (KNO 3 ), and minimum germination was observed in urea. Nutrient (phosphorus, calcium, and magnesium) deficiency significantly enhanced the germination frequency with maximum increase in magnesium (Mg) deficient condition. Further, supplementation of carbon sources (glucose, fructose, and sodium acetate) and growth hormones (IAA and GA) also enhanced the germination frequency in this cyanobacterium. Therefore, it may be concluded that, those factors supporting higher germination frequency could be considered for successful production and use of this cyanobacterium in biofertilizer and other algal production technologies. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Plasma and cyclotron frequency effects on output power of the plasma wave-pumped free-electron lasers

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

Zolghadr, S. H.; Jafari, S., E-mail: sjafari@guilan.ac.ir; Raghavi, A.

2016-05-15

Significant progress has been made employing plasmas in the free-electron lasers (FELs) interaction region. In this regard, we study the output power and saturation length of the plasma whistler wave-pumped FEL in a magnetized plasma channel. The small wavelength of the whistler wave (in sub-μm range) in plasma allows obtaining higher radiation frequency than conventional wiggler FELs. This configuration has a higher tunability by adjusting the plasma density relative to the conventional ones. A set of coupled nonlinear differential equations is employed which governs on the self-consistent evolution of an electromagnetic wave. The electron bunching process of the whistler-pumped FELmore » has been investigated numerically. The result reveals that for a long wiggler length, the bunching factor can appreciably change as the electron beam propagates through the wiggler. The effects of plasma frequency (or plasma density) and cyclotron frequency on the output power and saturation length have been studied. Simulation results indicate that with increasing the plasma frequency, the power increases and the saturation length decreases. In addition, when density of background plasma is higher than the electron beam density (i.e., for a dense plasma channel), the plasma effects are more pronounced and the FEL-power is significantly high. It is also found that with increasing the strength of the external magnetic field frequency, the power decreases and the saturation length increases, noticeably.« less

Directions of the relationship between substance use and depressive symptoms from adolescence to young adulthood.

PubMed

Wilkinson, Andra L; Halpern, Carolyn Tucker; Herring, Amy H

2016-09-01

Both substance use and depression are common in adolescence and often comorbid. Past research has produced conflicting results on whether there is a temporal relationship and if so, in which direction it operates and how it may vary by sex. The purpose of this paper is to explore the longitudinal, potentially bidirectional, relationships between high-frequency substance use and depressive symptoms from adolescence into young adulthood for males and females. Using data from the National Longitudinal Study of Adolescent to Adult Health we investigated longitudinal associations between high frequency substance use (alcohol, cigarettes, and marijuana) and depressive symptoms. The linear mixed effects models were stratified by sex and used a lagged measure of the dependent variable to test temporal relationships. A random intercept was used for respondent ID. Increases in depressive symptoms were significantly associated with a later increase of about a half day in marijuana use frequency for males and nearly a two day increase in smoking frequency for females. Conversely, increases in smoking frequency were significantly associated with approximately a 0.6-point increase for females and 0.4-point increase for males in depressive symptoms at a later wave. Results indicate a bidirectional relationship between smoking and depressive symptoms for females. For males, there was evidence supporting self-medication with marijuana and for smoking being associated with later increases in depressive symptoms. Results inform how substance use and depression screening, prevention and treatment efforts should be paired and targeted for males and females. Copyright © 2016 Elsevier Ltd. All rights reserved.

Frequency chirping for resonance-enhanced electron energy during laser acceleration

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

Gupta, D.N.; Suk, H.

2006-04-15

The model given by Singh-Tripathi [Phys. Plasmas 11, 743 (2004)] for laser electron acceleration in a magnetic wiggler is revisited by including the effect of laser frequency chirping. Laser frequency chirp helps to maintain the resonance condition longer, which increases the electron energy gain. A significant enhancement in electron energy gain during laser acceleration is observed.

Effect of low-frequency oscillation on performance of Hall thrusters

NASA Astrophysics Data System (ADS)

Liqiu, WEI; Wenbo, LI; Yongjie, DING; Daren, YU

2018-07-01

In this paper, a direct connection between the discharge current amplitude and the thruster performance is established by varying solely the capacitance of the filter unit of the Hall thrusters. To be precise, the variation characteristics of ion current, propellant utilization efficiency, and divergence angle of plume at different low-frequency oscillation amplitudes are measured. The findings demonstrate that in the case of the propellant in the discharge channel just meets or falls below the full ionization condition, the increase of low-frequency oscillation amplitude can significantly enhance the ionization degree of the neutral gas in the channel and increase the thrust and anode efficiency of thruster. On the contrary, the increase in the amplitude of low-frequency oscillation will lead to increase the loss of plume divergence, therefore the thrust and anode efficiency of thruster decrease.

Increased T-cell receptor mutation frequency in radiation-exposed residents living near the Semipalatinsk nuclear test site.

PubMed

Taooka, Yasuyuki; Takeichi, Nobuo; Noso, Yoshihiro; Kawano, Noriyuki; Apsalikov, Kazbek N; Hoshi, Masaharu

2006-02-01

From 1949 to 1989, 488 nuclear explosions were carried out in Semipalatinsk, and the cancer risk is increased in this region. Measuring somatic-cell mutation frequencies may be a useful tool for evaluating cancer risk within radiation-exposed populations. Here, we report the first evidence of increased T-cell receptor (TCR) mutations in peripheral blood from radiation-exposed residents of Semipalatinsk. The TCR mutation frequency in the highly exposed residents (Dolon and Sarzhal) was significantly higher than in the control group (Kokpekti). There was no statistically significant difference between the control group and the weakly exposed group (Kaynar and Semipalatinsk-city). The TCR mutation assay appeared to be a useful biological dosimeter even after a period of 40 years since radiation exposure. This may be the result of specific conditions, such as the presence of internal exposure.

[Effects of the frequency and intensity of nitrogen addition on soil pH, the contents of carbon, nitrogen and phosphorus in temperate steppe in Inner Mongolia, China.

PubMed

Zhou, Ji Dong; Shi, Rong Jiu; Zhao, Feng; Han, Si Qin; Zhang, Ying

2016-08-01

A four-year simulated nitrogen (N) deposition experiment involving nine N gradients and two N deposition frequencies (N was added either twice yearly or monthly) was conducted in Inner Mongolian grassland, to examine the effects of frequency and intensity of N addition on pH and the contents of carbon, nitrogen and phosphorus in soil. The results indicated that the soil pH and total phosphorus content, regardless of the N addition frequency, gradually decreased with the increase of N addition intensity. By contrast, the contents of soil available nitrogen and available phosphorus showed an increasing trend, while no significant variation in dissolved organic carbon (DOC) content was observed, and the contents of soil total carbon and total nitrogen had no change. Compared with the monthly N addition, the twice-a-year N addition substantially overestimated the effects of N deposition on decreasing the soil pH and increasing the available phosphorus content, but underestimated the effects of N deposition on increasing the soil available nitrogen content, and the significant difference was found in 0-5 cm soil layer.

Test-retest reliability of pure-tone thresholds from 0.5 to 16 kHz using Sennheiser HDA 200 and Etymotic Research ER-2 earphones.

PubMed

Schmuziger, Nicolas; Probst, Rudolf; Smurzynski, Jacek

2004-04-01

The purposes of the study were: (1) To evaluate the intrasession test-retest reliability of pure-tone thresholds measured in the 0.5-16 kHz frequency range for a group of otologically healthy subjects using Sennheiser HDA 200 circumaural and Etymotic Research ER-2 insert earphones and (2) to compare the data with existing criteria of significant threshold shifts related to ototoxicity and noise-induced hearing loss. Auditory thresholds in the frequency range from 0.5 to 6 kHz and in the extended high-frequency range from 8 to 16 kHz were measured in one ear of 138 otologically healthy subjects (77 women, 61 men; mean age, 24.4 yr; range, 12-51 yr) using HDA 200 and ER-2 earphones. For each subject, measurements of thresholds were obtained twice for both transducers during the same test session. For analysis, the extended high-frequency range from 8 to 16 kHz was subdivided into 8 to 12.5 and 14 to 16 kHz ranges. Data for each frequency and frequency range were analyzed separately. There were no significant differences in repeatability for the two transducer types for all frequency ranges. The intrasession variability increased slightly, but significantly, as frequency increased with the greatest amount of variability in the 14 to 16 kHz range. Analyzing each individual frequency, variability was increased particularly at 16 kHz. At each individual frequency and for both transducer types, intrasession test-retest repeatability from 0.5 to 6 kHz and 8 to 16 kHz was within 10 dB for >99% and >94% of measurements, respectively. The results indicated a false-positive rate of <3% in reference to the criteria for cochleotoxicity for both transducer types. In reference to the Occupational Safety and Health Administration Standard Threshold Shift criteria for noise-induced hazards, the results showed a minor false-positive rate of <1% for the HDA 200. Repeatability was similar for both transducer types. Intrasession test-retest repeatability from 0.5 to 12.5 kHz at each individual frequency including the frequency range susceptible to noise-induced hearing loss was excellent for both transducers. Repeatability was slightly, but significantly poorer in the frequency range from 14 to 16 kHz compared with the frequency ranges from 0.5 to 6 or 8 to 12.5 kHz. Measurements in the extended high-frequency range from 8 to 14 kHz, but not up to 16 kHz, may be recommended for monitoring purposes.

[Acute and remote biochemical and physiological effects of exhaustive weightlifting exercise].

PubMed

Minigalin, A D; Shumakov, A R; Baranova, T I; Danilova, M A; Kalinskiĭ, M I; Morozov, V I

2011-01-01

The goal of the work was a study of exhaustive weightlifting exercise effect on prolonged changes in physiological and biochemical variables characterized functional status of skeletal muscles. An exercise gave rise to significant blood lactate concentration increase that was indicative of an anaerobic metabolism to be a predominant mechanism of muscle contraction energy supply. A reduction of m. rectus femoris EMG activity (amplitude and frequency), tonus of tension and an increase in tonus of relaxation were found immediately after exercise. Both EMG amplitude and frequency were increased 1 day post-exercise. However, after 3 days of recovery, EMG amplitude and frequency were decreased again and, in parallel, blood serum creatine kinase (CK) activity was significantly increased. After 9 recovery days, all measured variables with the exception of CK were normalized. A significant reverse correlation was found between blood serum lactate concentration and m. rectus femoris EMG activity at the same time points. Blood serum CK activity and m. rectus femoris EMG and tonus variables were observed to be significantly reversely correlated on the 3rd post-exercise day. Presented data demonstrate that exhaustive exercise-induced muscle injury resulted in phase alterations in electrical activity and tonus which correlated with lactate concentration and CK activity in blood serum.

Modeling sound transmission of human middle ear and its clinical applications using finite element analysis.

PubMed

Chen, Shou-I; Lee, Ming-Hsiao; Yao, Chih-Min; Chen, Peir-Rong; Chou, Yuan-Fang; Liu, Tien-Chen; Song, Yu-Lin; Lee, Chia-Fone

2013-03-01

We have developed a new finite element (FE) model of human right ear, including the accurate geometry of middle ear ossicles, external ear canal, tympanic cavity, and mastoid cavity. The FE model would be suitable to study the dynamic behaviors of pathological middle ear conditions, including changes of stapedial ligament stiffness, tensor tympani ligament (TTL), and tympanic membrane (TM) stiffness and thickness. Increasing stiffness of stapedial ligament has substantial effect on stapes footplate movement, especially at low frequencies, but less effect on umbo movement. Softer TTL will result in increasing umbo and stapes footplate displacement, especially at low frequencies (f<1000Hz). When the TTL was detached, the vibration amplitude of umbo increased by 6dB at 600Hz and two peaks (300 and 600Hz) were found in the vibration amplitude of stapes footplate. Increasing the stiffness of tensor tympani resulted in a slightly decreased umbo amplitude at very low frequencies (f<500Hz) and significantly decreased displacement up to 12dB at middle frequencies (1000Hz1500Hz. As (TM) thickness was increased, the umbo displacement was reduced, especially at very low frequencies (f<600Hz). Otherwise, the stapes displacement was reduced at all frequencies. Copyright © 2013. Published by Elsevier B.V.

Frequency and duration of interval training programs and changes in aerobic power

NASA Technical Reports Server (NTRS)

Fox, E. L.; Bartels, R. L.; Obrien, R.; Bason, R.; Mathews, D. K.; Billings, C. E.

1975-01-01

The present study was designed to ascertain whether a training frequency of 2 days/wk for a 7- and 13-wk interval training program would produce improvement in maximal aerobic power comparable to that obtained from 7- and 13-wk programs of the same intensity consisting of 4 training days/wk. After training, there was a significant increase in maximal aerobic power that was independent of both training frequency and duration. Maximal heart rate was significantly decreased following training. Submaximal aerobic power did not change with training, but submaximal heart rate decreased significantly with greater decreases the more frequent and the longer the training.

Nonlinear frequency compression: Influence of start frequency and input bandwidth on consonant and vowel recognitiona)

PubMed Central

Alexander, Joshua M.

2016-01-01

By varying parameters that control nonlinear frequency compression (NFC), this study examined how different ways of compressing inaudible mid- and/or high-frequency information at lower frequencies influences perception of consonants and vowels. Twenty-eight listeners with mild to moderately severe hearing loss identified consonants and vowels from nonsense syllables in noise following amplification via a hearing aid simulator. Low-pass filtering and the selection of NFC parameters fixed the output bandwidth at a frequency representing a moderately severe (3.3 kHz, group MS) or a mild-to-moderate (5.0 kHz, group MM) high-frequency loss. For each group (n = 14), effects of six combinations of NFC start frequency (SF) and input bandwidth [by varying the compression ratio (CR)] were examined. For both groups, the 1.6 kHz SF significantly reduced vowel and consonant recognition, especially as CR increased; whereas, recognition was generally unaffected if SF increased at the expense of a higher CR. Vowel recognition detriments for group MS were moderately correlated with the size of the second formant frequency shift following NFC. For both groups, significant improvement (33%–50%) with NFC was confined to final /s/ and /z/ and to some VCV tokens, perhaps because of listeners' limited exposure to each setting. No set of parameters simultaneously maximized recognition across all tokens. PMID:26936574

The calcium–frequency response in the rat ventricular myocyte: an experimental and modelling study

PubMed Central

Gattoni, Sara; Røe, Åsmund Treu; Frisk, Michael; Louch, William E.; Niederer, Steven A.

2016-01-01

Key points In the majority of species, including humans, increased heart rate increases cardiac contractility. This change is known as the force–frequency response (FFR). The majority of mammals have a positive force–frequency relationship (FFR). In rat the FFR is controversial.We derive a species‐ and temperature‐specific data‐driven model of the rat ventricular myocyte.As a measure of the FFR, we test the effects of changes in frequency and extracellular calcium on the calcium–frequency response (CFR) in our model and three altered models.The results show a biphasic peak calcium–frequency response, due to biphasic behaviour of the ryanodine receptor and the combined effect of the rapid calmodulin buffer and the frequency‐dependent increase in diastolic calcium.Alterations to the model reveal that inclusion of Ca2+/calmodulin‐dependent protein kinase II (CAMKII)‐mediated L‐type channel and transient outward K+ current activity enhances the positive magnitude calcium–frequency response, and the absence of CAMKII‐mediated increase in activity of the sarco/endoplasmic reticulum Ca2+‐ATPase induces a negative magnitude calcium–frequency response. Abstract An increase in heart rate affects the strength of cardiac contraction by altering the Ca2+ transient as a response to physiological demands. This is described by the force–frequency response (FFR), a change in developed force with pacing frequency. The majority of mammals, including humans, have a positive FFR, and cardiac contraction strength increases with heart rate. However, the rat and mouse are exceptions, with the majority of studies reporting a negative FFR, while others report either a biphasic or a positive FFR. Understanding the differences in the FFR between humans and rats is fundamental to interpreting rat‐based experimental findings in the context of human physiology. We have developed a novel model of rat ventricular electrophysiology and calcium dynamics, derived predominantly from experimental data recorded under physiological conditions. As a measure of FFR, we tested the effects of changes in stimulation frequency and extracellular calcium concentration on the simulated Ca2+ transient characteristics and showed a biphasic peak calcium–frequency relationship, consistent with recent observations of a shift from negative to positive FFR when approaching the rat physiological frequency range. We tested the hypotheses that (1) inhibition of Ca2+/calmodulin‐dependent protein kinase II (CAMKII)‐mediated increase in sarco/endoplasmic reticulum Ca2+‐ATPase (SERCA) activity, (2) CAMKII modulation of SERCA, L‐type channel and transient outward K+ current activity and (3) Na+/K+ pump dynamics play a significant role in the rat FFR. The results reveal a major role for CAMKII modulation of SERCA in the peak Ca2+–frequency response, driven most significantly by the cytosolic calcium buffering system and changes in diastolic Ca2+. PMID:26916026

Characterization of silodosin and naftopidil in the treatment of bladder dysfunction in the spontaneously hypertensive rat.

PubMed

Saito, Motoaki; Shimizu, Shogo; Ohmasa, Fumiya; Oikawa, Ryo; Tsounapi, Panagiota; Dimitriadis, Fotios; Kinoshita, Yukako; Satoh, Keisuke

2013-04-01

As increasing evidence suggest that α(1)-blockers prevent benign prostatic hyperplasia related overactive bladder and nocturia in the human, we investigated the effects of silodosin and naftopidil on hypertension-related bladder dysfunction in the spontaneously hypertensive rat (SHR) model. Twelve-week-old male SHRs received no treatment or treatment with silodosin (100 µg/kg, p.o.) or naftopidil (10 or 30 mg/kg, p.o.) once daily for 6 weeks. Wistar rats were used as normotensive controls. After 6-week treatment, voiding functions were estimated by metabolic cages (dark- and light-cycle separately) and cystometric studies. Furthermore, the bladder blood flow (BBF) was measured employing the hydrogen clearance method. SHRs showed significant increases in micturition frequency, and decreases in BBF and single voided volume in both metabolic cages and cystometrograms compared to the Wistar group. Treatment with silodosin normalized the decreased BBF, and treatment with naftopidil increased the BBF in a dose-dependent manner in the SHR group. Although treatment with silodosin and the high dose of naftopidil significantly inhibited micturition frequency in one day, only treatment with the high dose of naftopidil significantly inhibited micturition frequency and urine production in the light-cycle compared to the non-treated SHRs. Although treatment with silodosin and the high dose of naftopidil significantly increased single voided volume, only treatment with silodosin significantly inhibited non-voiding contractions in the cystometrgrams. Our data suggest that both silodosin and naftopidil improve hypertension-related bladder dysfunction in the SHR, and naftopidil but not silodosin improves urinary frequency in the light-cycle due to inhibition of urine production. Copyright © 2012 Wiley Periodicals, Inc.

Sister chromatid exchange, (SCE), High-Frequency Cells (HFCs) and SCE distribution patterns in peripheral blood lymphocytes of Spanish adult smokers compared to non-smokers.

PubMed

Sebastià, Natividad; Hervás, David; Almonacid, Miguel; Villaescusa, Juan Ignacio; Soriano, José Miguel; Sahuquillo, Vicenta; Esteban, Valentín; Barquinero, Joan Francesc; Verdú, Gumersindo; Cervera, José; Such, Esperanza; Montoro, Alegría

2014-04-01

According to the International Agency for Research on Cancer, smoking tobacco is a major cause of cancer in humans. It causes about half of all male cancer deaths and an ever increasing number of cancer deaths in females. The aim of this study was to establish whether cigarette smoking increases sister chromatid exchanges (SCEs) in peripheral blood lymphocytes in two Spanish population groups; light and heavy smokers. The mean number of High-Frequency Cells (HFCs) was determined and, the SCE distribution pattern among the chromosomes was analysed represented by a ratio described below. A local sample of 101 adult smokers (n=48) and non-smokers (n=53), aged from 18 to 49 years, was studied using SCE levels in peripheral lymphocytes. Heavy smoking (≥ 10 cigarettes per day) increased significantly the SCE frequency and the HFC parameters. Neither age nor sex significantly influenced the frequencies in the groups studied. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Electrical and absorption properties of fresh cassava tubers and cassava starch

NASA Astrophysics Data System (ADS)

Harnsoongnoen, S.; Siritaratiwat, A.

2015-09-01

The objective of this study was to analyze the electrical and absorption properties of fresh cassava tubers and cassava starch at various frequencies using electric impedance spectroscopy and near-infrared spectroscopy, as well as determine the classification of the electrical parameters of both materials using the principle component analysis (PCA) method. All samples were measured at room temperature. The electrical and absorption parameters consisted of dielectric constant, dissipation factor, parallel capacitance, resistance, reactance, impedance and absorbance. It was found that the electrical and absorption properties of fresh cassava tubers and cassava starch were a function of frequency, and there were significant differences between the materials. The dielectric constant, parallel capacitance, resistance and impedance of fresh cassava tubers and cassava starch had similar dramatic decreases with increasing frequency. However, the reactance of both materials increased with an increasing frequency. The electrical parameters of both materials could be classified into two groups. Moreover, the dissipation factor and phase of impedance were the parameters that could be used in the separation of both materials. According to the absorbance patterns of the fresh cassava tubers and cassava starch, there were significant differences.

Association of auricular pressing and heart rate variability in pre-exam anxiety students.

PubMed

Wu, Wocao; Chen, Junqi; Zhen, Erchuan; Huang, Huanlin; Zhang, Pei; Wang, Jiao; Ou, Yingyi; Huang, Yong

2013-03-25

A total of 30 students scoring between 12 and 20 on the Test Anxiety Scale who had been exhibiting an anxious state > 24 hours, and 30 normal control students were recruited. Indices of heart rate variability were recorded using an Actiheart electrocardiogram recorder at 10 minutes before auricular pressing, in the first half of stimulation and in the second half of stimulation. The results revealed that the standard deviation of all normal to normal intervals and the root mean square of standard deviation of normal to normal intervals were significantly increased after stimulation. The heart rate variability triangular index, very-low-frequency power, low-frequency power, and the ratio of low-frequency to high-frequency power were increased to different degrees after stimulation. Compared with normal controls, the root mean square of standard deviation of normal to normal intervals was significantly increased in anxious students following auricular pressing. These results indicated that auricular pressing can elevate heart rate variability, especially the root mean square of standard deviation of normal to normal intervals in students with pre-exam anxiety.

Association of auricular pressing and heart rate variability in pre-exam anxiety students

PubMed Central

Wu, Wocao; Chen, Junqi; Zhen, Erchuan; Huang, Huanlin; Zhang, Pei; Wang, Jiao; Ou, Yingyi; Huang, Yong

2013-01-01

A total of 30 students scoring between 12 and 20 on the Test Anxiety Scale who had been exhibiting an anxious state > 24 hours, and 30 normal control students were recruited. Indices of heart rate variability were recorded using an Actiheart electrocardiogram recorder at 10 minutes before auricular pressing, in the first half of stimulation and in the second half of stimulation. The results revealed that the standard deviation of all normal to normal intervals and the root mean square of standard deviation of normal to normal intervals were significantly increased after stimulation. The heart rate variability triangular index, very-low-frequency power, low-frequency power, and the ratio of low-frequency to high-frequency power were increased to different degrees after stimulation. Compared with normal controls, the root mean square of standard deviation of normal to normal intervals was significantly increased in anxious students following auricular pressing. These results indicated that auricular pressing can elevate heart rate variability, especially the root mean square of standard deviation of normal to normal intervals in students with pre-exam anxiety. PMID:25206734

Experimental Investigation of a Preloaded Spring-tab Flutter Model

NASA Technical Reports Server (NTRS)

Smith, N H; Clevenson, S A; Barmby, J G

1947-01-01

An experimental investigation was made of a preloaded spring-tab flutter model to determine the effects on flutter speed of aspect ratio, tab frequency, and preloaded spring constant. The rudder was mass-balanced, and the flutter mode studied was essentially one of three degrees of freedom (fin bending coupled with rudder and tab oscillations). Inasmuch as the spring was preloaded, the tab-spring system was a nonlinear one. Frequency of the tab was the most significant parameter in this study, and an increase in flutter speed with increasing frequency is indicated. At a given frequency, the tab of high aspect ratio is shown to have a slightly lower flutter speed than the one of low aspect ratio. Because the frequency of the preloaded spring tab was found to vary radically with amplitude, the flutter speed decreased with increase in initial displacement of the tab.

Frequency difference limens at high frequencies: evidence for a transition from a temporal to a place code.

PubMed

Moore, Brian C J; Ernst, Stephan M A

2012-09-01

It is commonly believed that difference limens for frequency (DLFs) for pure tones depend on a temporal mechanism (phase locking) for frequencies up to 4-5 kHz and a place mechanism at higher frequencies. The DLFs predicted from a place mechanism, expressed as a proportion of center frequency (Δf/f), should be approximately invariant with frequency at medium to high frequencies. If there is a transition from a temporal to a place mechanism, Δf/f should increase with increasing center frequency until the transition occurs, and then reach a plateau. Published data do not show such an effect. In this study, DLFs were measured for center frequencies from 2 to 14 kHz, using earphones designed to produce a flat response at the eardrum. The level of every tone was varied over a range of ±4 dB, to reduce loudness cues. The value of Δf/f increased progressively from 2 to 8 kHz, but did not change significantly for frequencies from 8 to 14 kHz. The results are consistent with the idea that there is a transition from a temporal to a place mechanism at about 8 kHz, rather than at 4-5 kHz, as is commonly assumed.

The effects of passive leg press training on jumping performance, speed, and muscle power.

PubMed

Liu, Chiang; Chen, Chuan-Shou; Ho, Wei-Hua; Füle, Róbert János; Chung, Pao-Hung; Shiang, Tzyy-Yuang

2013-06-01

Passive leg press (PLP) training was developed based on the concepts of the stretch-shortening cycle (SSC) and the benefits of high muscle contraction velocity. Passive leg press training enables lower limb muscle groups to apply a maximum downward force against a platform moved up and down at high frequency by an electric motor. Thus, these muscle groups accomplished both concentric and eccentric isokinetic contractions in a passive, rapid, and repetitive manner. This study investigates the effects of 10 weeks of PLP training at high and low movement frequencies have on jumping performance, speed, and muscle power. The authors selected 30 college students who had not performed systematic resistance training in the previous 6 months, including traditional resistance training at a squat frequency of 0.5 Hz, PLP training at a low frequency of 0.5 Hz, and PLP training at a high frequency of 2.5 Hz, and randomly divided them into 3 groups (n = 10). The participants' vertical jump, drop jump, 30-m sprint performance, explosive force, and SSC efficiency were tested under the same experimental procedures at pre- and post-training. Results reveal that high-frequency PLP training significantly increased participants' vertical jump, drop jump, 30-m sprint performance, instantaneous force, peak power, and SSC efficiency (p < 0.05). Additionally, their change rate abilities were substantially superior to those of the traditional resistance training (p < 0.05). The low-frequency PLP training significantly increased participants' vertical jump, 30-m sprint performance, instantaneous force, and peak power (p < 0.05). However, traditional resistance training only increased participants' 30-m sprint performance and peak power (p < 0.05). The findings suggest that jump performance, speed, and muscle power significantly improved after 10 weeks of PLP training at high movement frequency. A PLP training machine powered by an electrical motor enables muscles of the lower extremities to contract faster compared with voluntary contraction. Therefore, muscle training with high contraction velocity is one of the main methods of increasing muscle power. Passive leg press training is a unique method for enhancing jump performance, speed, and muscle power.

Effects of whole body heating on dynamic baroreflex regulation of heart rate in humans

NASA Technical Reports Server (NTRS)

Crandall, C. G.; Zhang, R.; Levine, B. D.

2000-01-01

The purpose of this project was to identify whether dynamic baroreflex regulation of heart rate (HR) is altered during whole body heating. In 14 subjects, dynamic baroreflex regulation of HR was assessed using transfer function analysis. In normothermic and heat-stressed conditions, each subject breathed at a fixed rate (0. 25 Hz) while beat-by-beat HR and systolic blood pressure (SBP) were obtained. Whole body heating significantly increased sublingual temperature, HR, and forearm skin blood flow. Spectral analysis of HR and SBP revealed that the heat stress significantly reduced HR and SBP variability within the high-frequency range (0.2-0.3 Hz), reduced SBP variability within the low-frequency range (0.03-0.15 Hz), and increased the ratio of low- to high-frequency HR variability (all P < 0.01). Transfer function gain analysis showed that the heat stress reduced dynamic baroreflex regulation of HR within the high-frequency range (from 1.04 +/- 0.06 to 0.54 +/- 0.6 beats. min(-1). mmHg(-1); P < 0.001) without significantly affecting the gain in the low-frequency range (P = 0.63). These data suggest that whole body heating reduced high-frequency dynamic baroreflex regulation of HR associated with spontaneous changes in blood pressure. Reduced vagal baroreflex regulation of HR may contribute to reduced orthostatic tolerance known to occur in humans during heat stress.

Music Attenuated a Decrease in Parasympathetic Nervous System Activity after Exercise.

PubMed

Jia, Tiantian; Ogawa, Yoshiko; Miura, Misa; Ito, Osamu; Kohzuki, Masahiro

2016-01-01

Music and exercise can both affect autonomic nervous system activity. However, the effects of the combination of music and exercise on autonomic activity are poorly understood. Additionally, it remains unknown whether music affects post-exercise orthostatic tolerance. The aim of this study was to evaluate the effects of music on autonomic nervous system activity in orthostatic tolerance after exercise. Twenty-six healthy graduate students participated in four sessions in a random order on four separate days: a sedentary session, a music session, a bicycling session, and a bicycling with music session. Participants were asked to listen to their favorite music and to exercise on a cycle ergometer. We evaluated autonomic nervous system activity before and after each session using frequency analysis of heart rate variability. High frequency power, an index of parasympathetic nervous system activity, was significantly increased in the music session. Heart rate was increased, and high frequency power was decreased, in the bicycling session. There was no significant difference in high frequency power before and after the bicycling with music session, although heart rate was significantly increased. Additionally, both music and exercise did not significantly affect heart rate, systolic blood pressure or also heart rate variability indices in the orthostatic test. These data suggest that music increased parasympathetic activity and attenuated the exercise-induced decrease in parasympathetic activity without altering the orthostatic tolerance after exercise. Therefore, music may be an effective approach for improving post-exercise parasympathetic reactivation, resulting in a faster recovery and a reduction in cardiac stress after exercise.

Over-vibration induced blood perfusion and vascular permeability changes may lead to vocal edema.

PubMed

Wang, Jiajia; Devine, Erin; Fang, Rui; Jiang, Jack J

2017-01-01

To observe blood perfusion and vascular permeability changes under varying vibration frequency exposures. Animal model. Blood perfusion was measured using laser Doppler flowmetry in eight rabbit auricular vessels (four rabbits) under nonvibration, and 62.5-Hz/1-mm, 125-Hz/1-mm, and 250-Hz/0.5-mm vibration frequency/amplitude exposures. Another 12 rabbits were randomly divided into vibration only and vibration with histamine groups. After 3 hours of continuous 125-Hz, 1-mm amplitude vibration of the auricle, vascular permeability was analyzed by absorbance of Evans blue-albumin complex. Significantly lower blood perfusion was observed in the vibration group, compared with no vibration exposure controls. Blood perfusion decreased 29 ± 16% as the vibration frequency was increased from 62.5 Hz to 125 Hz with the vibration amplitude constant at 1 mm. When the frequency was increased from 125 Hz to 250 Hz, while the amplitude was decreased from 1 mm to 0.5 mm, blood flow perfusion further decreased 29 ± 29%, and the decline tendency in blood perfusion showed no significant difference (P = .992). Meanwhile, in the vibration with histamine group, vascular permeability of the vibrated ears increased significantly compared to the nonvibrated ears (P = .005). Overvibration of the vocal folds due to voice overuse or abuse may significantly reduce blood perfusion, and increase vascular permeability in the vocal fold in inflammatory situations, which may lead to the formation of vocal edema. NA Laryngoscope, 127:148-152, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Intravesical PAC1 Receptor Antagonist, PACAP(6–38), Reduces Urinary Bladder Frequency and Pelvic Sensitivity in NGF-OE Mice

PubMed Central

Girard, Beatrice M.; Malley, Susan E.; Mathews, Morgan M.; May, Victor

2017-01-01

Chronic NGF overexpression (OE) in the urothelium, achieved through the use of a highly urothelium-specific uroplakin II promoter, stimulates neuronal sprouting in the urinary bladder, produces increased voiding frequency and non-voiding contractions, and referred somatic sensitivity. Additional NGF-mediated pleiotropic changes might contribute to increased voiding frequency and pelvic hypersensitivity in NGF-OE mice such as neuropeptide/receptor systems including PACAP(Adcyap1) and PAC1 receptor (Adcyap1r1). Given the presence of PAC1-immunoreactive fibers and the expression of PAC1 receptor expression in bladder tissues, and PACAP-facilitated detrusor contraction, whether PACAP/receptor signaling contributes to increased voiding frequency and somatic sensitivity was evaluated in NGF-OE mice. Intravesical administration of the PAC1 receptor antagonist, PACAP(6–38) (300 nM), significantly (p ≤ 0.01) increased intercontraction interval (2.0-fold) and void volume (2.5-fold) in NGF-OE mice. Intravesical instillation of PACAP(6–38) also decreased baseline bladder pressure in NGF-OE mice. PACAP(6–38) had no effects on bladder function in WT mice. Intravesical administration of PACAP(6–38) (300 nM) significantly (p ≤ 0.01) reduced pelvic sensitivity in NGF-OE mice but was without effect in WT mice. PACAP/receptor signaling contributes to the increased voiding frequency and pelvic sensitivity observed in NGF-OE mice. PMID:27146136

Toxicity of flavor enhancers to the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae).

PubMed

Zheng, Chunyan; Yang, Dongyu; Li, Zhiqiang; Xu, Yijuan

2018-04-11

The objective of this study was to evaluate the toxicity of flavor enhancers to the oriental fruit fly Bactrocera dorsalis (Hendel). The flavor enhancers glycine, disodium guanylate, succinic acid disodium salt, monosodium glutamate (MSG), disodium inosinate, and L-alanine significantly increased the mortality of B. dorsalis flies. The mortality of flies that fed on glycine, disodium guanylate, succinic acid disodium salt, and MSG was greater than 90%. Additionally, fruit fly mortality increased with increases in both time and concentration. Glycine not only reduced the climbing ability of B. dorsalis but also affected the duration and frequency of its behavioral patterns (flight, walking, grooming and inactivity). Compared with adult flies in the control group, adult B. dorsalis flies that fed on glycine exhibited a significantly increased duration and frequency of inactivity and a decreased duration and frequency of both flight and walking. However, the effect of glycine on grooming activity was not significant. These findings demonstrate the toxic effects of flavor enhancers on B. dorsalis. Glycine also affected the behavior of adult flies at a low dose. Therefore, glycine has potentially toxic to insects and also likely to have a negative impact at sublethal concentrations.

Changes in the frequencies of human hematopoietic stem and progenitor cells with age and site

PubMed Central

Farrell, TL; McGuire, TR; Bilek, L; Brusnahan, SK; Jackson, JD; Lane, JT; Garvin, KL; O'Kane, BJ; Berger, AM; Tuljapurkar, SR; Kessinger, MA; Sharp, JG

2013-01-01

This study enumerated CD45hi/CD34+ and CD45hi/CD133+ human hematopoietic stem cells (HSC) and granulocyte-monocyte colony forming (GM-CFC) progenitor cells in blood and trochanteric and femoral bone marrow in 233 individuals. Stem cell frequencies were determined by multi-parameter flow cytometry employing an internal control to determine the intrinsic variance of the assays. Progenitor cell frequency was determined using a standard colony assay technique. The frequency of outliers from undetermined methodological causes was highest for blood but less than 5% for all values. The frequency of CD45hi/CD133+ cells correlated highly with the frequency of CD45hi/CD34+ cells in trochanteric and femoral bone marrow. The frequency of these HSC populations in trochanteric and femoral bone marrow rose significantly with age. In contrast, there was no significant trend of either of these cell populations with age in the blood. Trochanteric marrow GM-CFC progenitor cells showed no significant trends with age, but femoral marrow GM-CFC trended downward with age, potentially because of the reported conversion of red marrow at this site to fat with age. Hematopoietic stem and progenitor cells exhibited changes in frequencies with age that differed between blood and bone marrow. We previously reported that side population (SP) multipotential HSC, that include the precursors of CD45hi/CD133+ and CD45hi/CD34+, decline with age. Potentially the increases in stem cell frequencies in the intermediate compartment between SP and GM progenitor cells observed in this study represent a compensatory increase for the loss of more potent members of the HSC hierarchy. PMID:24246745

Compressible flows with periodic vortical disturbances around lifting airfoils. Ph.D. Thesis - Notre Dame Univ.

NASA Technical Reports Server (NTRS)

Scott, James R.

1991-01-01

A numerical method is developed for solving periodic, three-dimensional, vortical flows around lifting airfoils in subsonic flow. The first-order method that is presented fully accounts for the distortion effects of the nonuniform mean flow on the convected upstream vortical disturbances. The unsteady velocity is split into a vortical component which is a known function of the upstream flow conditions and the Lagrangian coordinates of the mean flow, and an irrotational field whose potential satisfies a nonconstant-coefficient, inhomogeneous, convective wave equation. Using an elliptic coordinate transformation, the unsteady boundary value problem is solved in the frequency domain on grids which are determined as a function of the Mach number and reduced frequency. The numerical scheme is validated through extensive comparisons with known solutions to unsteady vortical flow problems. In general, it is seen that the agreement between the numerical and analytical results is very good for reduced frequencies ranging from 0 to 4, and for Mach numbers ranging from .1 to .8. Numerical results are also presented for a wide variety of flow configurations for the purpose of determining the effects of airfoil thickness, angle of attack, camber, and Mach number on the unsteady lift and moment of airfoils subjected to periodic vortical gusts. It is seen that each of these parameters can have a significant effect on the unsteady airfoil response to the incident disturbances, and that the effect depends strongly upon the reduced frequency and the dimensionality of the gust. For a one-dimensional (transverse) or two-dimensional (transverse and longitudinal) gust, the results indicate that airfoil thickness increases the unsteady lift and moment at the low reduced frequencies but decreases it at the high reduced frequencies. The results show that an increase in airfoil Mach number leads to a significant increase in the unsteady lift and moment for the low reduced frequencies, but a significant decrease for the high reduced frequencies.

Recording of amplitude-integrated electroencephalography, oxygen saturation, pulse rate, and cerebral blood flow during massage of premature infants.

PubMed

Rudnicki, Jacek; Boberski, Marek; Butrymowicz, Ewa; Niedbalski, Paweł; Ogniewski, Paweł; Niedbalski, Marek; Niedbalski, Zbigniew; Podraza, Wojciech; Podraza, Hanna

2012-08-01

Stimulation of the nervous system plays an important role in brain function and psychomotor development of children. Massage can benefit premature infants, but has limitations. The authors conducted a study to verify the direct effects of massage on amplitude-integrated electroencephalography (aEEG), oxygen saturation (SaO(2)), and pulse analyzed by color cerebral function monitor (CCFM) and cerebral blood flow assessed by the Doppler technique. The amplitude of the aEEG trend during massage significantly increased. Massage also impacted the dominant frequency δ waves. Frequency significantly increased during the massage and return to baseline after treatment. SaO(2) significantly decreased during massage. In four premature infants, massage was discontinued due to desaturation below 85%. Pulse frequency during the massage decreased but remained within physiological limits of greater than 100 beats per minute in all infants. Doppler flow values in the anterior cerebral artery measured before and after massage did not show statistically significant changes. Resistance index after massage decreased, which might provide greater perfusion of the brain, but this difference was not statistically significant. Use of the CCFM device allows for monitoring of three basic physiologic functions, namely aEEG, SaO(2), and pulse, and increases the safety of massage in preterm infants. Copyright © 2012 by Thieme Medical Publishers

Segmentation of the Thalamus Based on BOLD Frequencies Affected in Temporal Lobe Epilepsy

PubMed Central

Morgan, Victoria L.; Rogers, Baxter P.; Abou-Khalil, Bassel

2015-01-01

Objective Temporal lobe epilepsy is associated with functional changes throughout the brain, particularly including a putative seizure propagation network involving the hippocampus, insula and thalamus. We identified a specified frequency range where functional connectivity in this network was related to duration of disease. Then, to identify specific thalamic nuclei involved in seizure propagation, we determined the subregions of the thalamus that have increased resting functional oscillations in this frequency range. Methods Resting-state functional MRI (fMRI) was acquired from twenty unilateral TLE (14 right, 6 left) patients and twenty healthy controls who were each age and gender matched to a specific patient. Wavelet based functional MRI connectivity mapping across the network was computed at each frequency to determine those frequencies where connectivity significantly decreases with duration of disease consistent with impairment due to repeated seizures. The voxel-wise power of the spontaneous blood oxygenation fluctuations of this frequency band was computed in the thalamus of each subject. Results Functional connectivity was impaired in the proposed seizure propagation network over a specific range (0.0067–0.013 Hz and 0.024–0.032 Hz) of blood oxygenation oscillations. Increased power in this frequency band (<0.032 Hz) was detected bilaterally in the pulvinar and anterior nucleus of the thalamus of healthy controls, and was increased over the ipsilateral thalamus compared to the contralateral thalamus in TLE. Significance This study identified frequencies of impaired connectivity in a TLE seizure propagation network and used them to localize the anterior nucleus and pulvinar of the thalamus as subregions most susceptible to TLE seizures. Further examinations of these frequencies in healthy and TLE subjects may provide unique information relating to the mechanism of seizure propagation and potential treatment using electrical stimulation. PMID:26360535

Cause-effect relationship between vocal fold physiology and voice production in a three-dimensional phonation model

PubMed Central

Zhang, Zhaoyan

2016-01-01

The goal of this study is to better understand the cause-effect relation between vocal fold physiology and the resulting vibration pattern and voice acoustics. Using a three-dimensional continuum model of phonation, the effects of changes in vocal fold stiffness, medial surface thickness in the vertical direction, resting glottal opening, and subglottal pressure on vocal fold vibration and different acoustic measures are investigated. The results show that the medial surface thickness has dominant effects on the vertical phase difference between the upper and lower margins of the medial surface, closed quotient, H1-H2, and higher-order harmonics excitation. The main effects of vocal fold approximation or decreasing resting glottal opening are to lower the phonation threshold pressure, reduce noise production, and increase the fundamental frequency. Increasing subglottal pressure is primarily responsible for vocal intensity increase but also leads to significant increase in noise production and an increased fundamental frequency. Increasing AP stiffness significantly increases the fundamental frequency and slightly reduces noise production. The interaction among vocal fold thickness, stiffness, approximation, and subglottal pressure in the control of F0, vocal intensity, and voice quality is discussed. PMID:27106298

Decline in frequency of the 2La chromosomal inversion in Anopheles gambiae (s.s.) in Western Kenya: correlation with increase in ownership of insecticide-treated bed nets.

PubMed

Matoke-Muhia, Damaris; Gimnig, John E; Kamau, Luna; Shililu, Josephat; Bayoh, M Nabie; Walker, Edward D

2016-06-10

The 2La chromosomal inversion, a genetic polymorphism in An. gambiae (sensu stricto) (s.s.), is associated with adaptation to microclimatic differences in humidity and desiccation resistance and mosquito behaviors. Ownership of insecticide-treated bed nets (ITNs) for malaria control has increased markedly in western Kenya in the last 20 years. An increase in the frequency of ITNs indoors could select against house entering or indoor resting of Anopheles mosquitoes. Thus, the frequency of the 2La inversion is postulated to change in An. gambiae (s.s.) with the increase of ITN ownership over time. Anopheles gambiae mosquitoes were sampled between 1994 and 2011 using pyrethrum knockdown, bednet traps and human landing catches (HLC) from Asembo and Seme, western Kenya. The 2La inversion was detected by a PCR assay with primers designed for proximal breakpoints of the 2La/a and 2L+(a)/+(a) chromosomal conformation. Mosquitoes were tested for malaria parasite infection by sporozoite ELISA. The frequency of the 2La chromosomal inversion declined from 100 % of all chromosomes in 1994 to 17 % in 2005 and remained low through 2011 (21 %). ITN ownership increased from 0 to > 90 % of houses in the study area during this interval. The decline in the frequency of the 2La chromosomal inversion was significantly, negatively correlated with year (r = -0.93) and with increase in ITN ownership (r = -0.96). The frequency of the homo- and heterokaryotypes departed significantly from Hardy-Weinberg equilibrium, suggesting that 2La/a karyotype was under selection, earlier in its favor and later, against it. Precipitation and maximum monthly temperature did not vary over time, therefore there was no trend in climate that could account for the decline. There was no significant difference in frequency of the 2La inversion in An. gambiae (s.s.) females sampled indoors or outdoors in HCL in 2011, nor was there an association between the 2La inversion and infection with Plasmodium falciparum sporozoites. The increase in ITN ownership in the study area was negatively correlated with the frequency of 2La inversion. The decline in 2La frequency in western Kenya is postulated to be due to differential impacts of ITNs on mosquitoes with different 2La karyotypes, possibly mediated by differences in behavior associated with the 2La karyotypes. Further research is required to determine if this is a widespread phenomenon, to further determine the association of the 2La karyotypes with mosquito behavior, and to assess whether ITNs are exerting selection mediated by differences in behavior on the different karyotypes.

The Sensitivity of Adolescent Hearing Screens Significantly Improves by Adding High Frequencies.

PubMed

Sekhar, Deepa L; Zalewski, Thomas R; Beiler, Jessica S; Czarnecki, Beth; Barr, Ashley L; King, Tonya S; Paul, Ian M

2016-09-01

One in 6 US adolescents has high-frequency hearing loss, often related to hazardous noise. Yet, the American Academy of Pediatrics (AAP) hearing screen (500, 1,000, 2,000, 4,000 Hertz) primarily includes low frequencies (<3,000 Hertz). Study objectives were to determine (1) sensitivity and specificity of the AAP hearing screen for adolescent hearing loss and (2) if adding high frequencies increases sensitivity, while repeat screening of initial referrals reduces false positive results (maintaining acceptable specificity). Eleventh graders (n = 134) participated in hearing screening (2013-2014) including "gold-standard" sound-treated booth testing to calculate sensitivity and specificity. Of the 43 referrals, 27 (63%) had high-frequency hearing loss. AAP screen sensitivity and specificity were 58.1% (95% confidence interval 42.1%-73.0%) and 91.2% (95% confidence interval 83.4-96.1), respectively. Adding high frequencies (6,000, 8,000 Hertz) significantly increased sensitivity to 79.1% (64.0%-90.0%; p = .003). Specificity with repeat screening was 81.3% (71.8%-88.7%; p = .003). Adolescent hearing screen sensitivity improves with high frequencies. Repeat testing maintains acceptable specificity. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Distinct tumor protein p53 mutants in breast cancer subgroups.

PubMed

Dumay, Anne; Feugeas, Jean-Paul; Wittmer, Evelyne; Lehmann-Che, Jacqueline; Bertheau, Philippe; Espié, Marc; Plassa, Louis-François; Cottu, Paul; Marty, Michel; André, Fabrice; Sotiriou, Christos; Pusztai, Lajos; de Thé, Hugues

2013-03-01

Tumor protein p53 (TP53) is mutated in approximately 30% of breast cancers, but this frequency fluctuates widely between subclasses. We investigated the p53 mutation status in 572 breast tumors, classified into luminal, basal and molecular apocrine subgroups. As expected, the lowest mutation frequency was observed in luminal (26%), and the highest in basal (88%) tumors. Luminal tumors showed significantly higher frequency of substitutions (82 vs. 65%), notably A/T to G/C transitions (31 vs. 15%), whereas molecular apocrine and basal tumors presented much higher frequencies of complex mutations (deletions/insertions) (36 and 33%, respectively, vs. 18%). Accordingly, missense mutations were significantly more frequent in luminal tumors (75 vs. 54%), whereas basal tumors displayed significantly increased rates of TP53 truncations (43 vs. 25%), resulting in loss of function and/or expression. Interestingly, as basal tumors, molecular apocrine tumors presented with a high rate of complex mutations, but paradoxically, these were not associated with increased frequency of p53 truncation. As in luminal tumors, this could reflect a selective pressure for p53 gain of function, possibly through P63/P73 inactivation. Collectively, these observations point not only to different mechanisms of TP53 alterations, but also to different functional consequences in the different breast cancer subtypes. Copyright © 2012 UICC.

Changes in the type of precipitation and associated cloud types in Eastern Romania (1961-2008)

NASA Astrophysics Data System (ADS)

Manea, Ancuta; Birsan, Marius-Victor; Tudorache, George; Cărbunaru, Felicia

2016-03-01

Recent climate change is characterized (among other things) by changes in the frequency of some meteorological phenomena. This paper deals with the long-term changes in various precipitation types, and the connection between their variability and cloud type frequencies, at 11 meteorological stations from Eastern Romania over 1961-2008. These stations were selected with respect to data record completeness for all considered variables (weather phenomena and cloud type). The meteorological variables involved in the present study are: monthly number of days with rain, snowfall, snow showers, rain and snow (sleet), sleet showers and monthly frequency of the Cumulonimbus, Nimbostratus and Stratus clouds. Our results show that all stations present statistically significant decreasing trends in the number of days with rain in the warm period of the year. Changes in the frequency of days for each precipitation type show statistically significant decreasing trends for non-convective (stratiform) precipitation - rain, drizzle, sleet and snowfall -, while the frequencies of rain shower and snow shower (convective precipitation) are increasing. Cloud types show decreasing trends for Nimbostratus and Stratus, and increasing trends for Cumulonimbus.

[Effect of flooding time length on mycorrhizal colonization of three AM fungi in two wetland plants].

PubMed

Ma, Lei-Meng; Wang, Peng-Teng; Wang, Shu-Guang

2014-01-01

In order to provide information for elucidating effect of flooding on the formation and function of AM in wetland plants, three AM fungi (Glomus intraradices, Glomus versiforme, Glomus etunicatum) were used to investigate the effects of flooding time length on their colonization in cattail (Typha orientalis) and rice (Oryza sativa L. ). The results showed that the mycorrhizal colonization rate (MCR) presented downtrend with increasing flooding time length. In cattail, MCR of the fungus F3 was higher than those of fungi F1 and F2, but no significant difference in MCR was found between fungi F1 and F2. In rice, the MCRs of fungi F2 and F3 were higher than that of E1. In both plants, the proportional frequency of hyphae was the highest while the proportional frequency of arbuscules and vesicles was very low in all treatments, indicating that hyphal colonization was the main route for AM formation. The proportional frequency of hyphae in cattail increased with the flooding time length, but no significant trend was observed in rice plant. The proportional frequency of arhuscules decreased with the increase of flooding time, and was the highest in the treatment without flooding (treatment IV). The number of spores produced by AM fungi increased with increasing flooding time, and reached the highest in the treatment of long time flooding (treatment I). In the same treatment, the fungus F3 produced more spores than fungi F1 and F2. Changes in wet weight of the two plants showed that AM could increase cattail growth under flooding, hut little effect on rice growth was found. It is concluded that flooding time length significantly affected the mycorrhizal colonization rate and the proportional frequency of colonization. AM could enhance the growth of wetland plant, but this depends on the mycorrhizal dependence of host plant on AM fungi. Therefore, flooding time length should be considered in the inoculation of wetland plants with AM fungi.

Radiation Performance of Commercial SiGe HBT BiCMOS-High Speed Operational Amplifiers

NASA Technical Reports Server (NTRS)

Chen, Dakai; Pellish, Jonathan; Phan, Anthony; Kim, Hak; Burns, Sam; Albarian, Rafi; Holcombe, Bruce; Little, Bradley; Salzman, James; LaBel, Kenneth

2010-01-01

We present results on heavy-ion and proton irradiations for commercial SiGe BiCMOS operational amplifiers: LTC6400-20 from Linear Technology and THS4304 from Texas Instruments. We found that the devices are susceptible to heavy-ion-induced SETs. The SET cross-sections increase with increasing operating frequency. The LTC6400 exhibits a LET(sub th) < 7.4 MeV·sq cm/mg for frequencies ranging from 10 to 1000 MHz. The THS4304 exhibits a LET(sub th) < 4.4 MeV·sq cm/mg at 200 MHz; the LET(sub th) decreases with increasing frequency. The significance of the SETs also increases with frequency. The SETs at 1000 MHz can erase several signal cycles. We al.so found that the LTC6400 is relatively robust against 198 and 54 MeV protons. We did not observe angular sensitivity from the proton irradiations.

Identification of trends in intensity and frequency of extreme rainfall events in part of the Indian Himalaya

NASA Astrophysics Data System (ADS)

Bhardwaj, Alok; Ziegler, Alan D.; Wasson, Robert J.; Chow, Winston; Sharma, Mukat L.

2017-04-01

Extreme monsoon rainfall is the primary reason of floods and other secondary hazards such as landslides in the Indian Himalaya. Understanding the phenomena of extreme monsoon rainfall is therefore required to study the natural hazards. In this work, we study the characteristics of extreme monsoon rainfall including its intensity and frequency in the Garhwal Himalaya in India, with a focus on the Mandakini River Catchment, the site of devastating flood and multiple large landslides in 2013. We have used two long term rainfall gridded data sets: the Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE) product with daily rainfall data from 1951-2007 and the India Meteorological Department (IMD) product with daily rainfall data from 1901 to 2013. Two methods of Mann Kendall and Sen Slope estimator are used to identify the statistical significance and magnitude of trends in intensity and frequency of extreme monsoon rainfall respectively, at a significance level of 0.05. The autocorrelation in the time series of extreme monsoon rainfall is identified and reduced using the methods of: pre-whitening, trend-free pre-whitening, variance correction, and block bootstrap. We define extreme monsoon rainfall threshold as the 99th percentile of time series of rainfall values and any rainfall depth greater than 99th percentile is considered as extreme in nature. With the IMD data set, significant increasing trend in intensity and frequency of extreme rainfall with slope magnitude of 0.55 and 0.02 respectively was obtained in the north of the Mandakini Catchment as identified by all four methods. Significant increasing trend in intensity with a slope magnitude of 0.3 is found in the middle of the catchment as identified by all methods except block bootstrap. In the south of the catchment, significant increasing trend in intensity with a slope magnitude of 0.86 for pre-whitening method and 0.28 for trend-free pre-whitening and variance correction methods was obtained. Further, increasing trend in frequency with a slope magnitude of 0.01 was identified by three methods except block bootstrap in the south of the catchment. With the APHRODITE data set, we obtained significant increasing trend in intensity with a slope magnitude of 1.27 at the middle of the catchment as identified by all four methods. Collectively, both the datasets show signals of increasing intensity, and IMD shows results for increasing frequency in the Mandakini Catchment. The increasing occurrence of extreme events, as identified here, is becoming more disastrous because of rising human population and infrastructure in the Mandakini Catchment. For example, the 2013 flood due to extreme rainfall was catastrophic in terms of loss of human and animal lives and destruction of the local economy. We believe our results will help understand more about extreme rainfall events in the Mandakini Catchment and in the Indian Himalaya.

Kinematics of the tooth tapping movement.

PubMed

Widmalm, S E; Hedegård, B

1977-07-01

Electrical activity in the masseter muscles and tooth contact vibrations were recorded simultaneously from subjects tapping their teeth slowly into maximal intercuspidation and again with maximal frequency. High speed cinephotography was also used with four of the ten subjects. Three main parts could be distinguished on the obtained graphical representation of the tooth tapping movement: tooth contact phase (TCP), opening phase (OP) and closing phase (CP). Tapping frequency was increased by decreasing the jaw opening degree and the durations of TCP, OP and CP. The jaw velocity immediately before tooth contact, which may be of significance for the reflex response, was however not increased. The average jaw speed was nevertheless increased from 10 to 15 cm/s since the turning from OP to CP was more abrupt in high than in low frequency tapping. The duration of electrical activity after tooth contact was significantly shorter at tapping with high than with low frequency. The teeth maintained contact without detectable rebound between each open-close cycle. The OP started about 100 ms after the cessation of electrical activity both at low and high tapping frequency. The time between end of electrical activity and the start of a new OP was supposed to be dependent upon the relaxation time of the masseter muscles.

Ventilation rates and activity levels of juvenile jumbo squid under metabolic suppression in the oxygen minimum zone.

PubMed

Trübenbach, Katja; Pegado, Maria R; Seibel, Brad A; Rosa, Rui

2013-02-01

The Humboldt (jumbo) squid, Dosidicus gigas, is a part-time resident of the permanent oxygen minimum zone (OMZ) in the Eastern Tropical Pacific and, thereby, it encounters oxygen levels below its critical oxygen partial pressure. To better understand the ventilatory mechanisms that accompany the process of metabolic suppression in these top oceanic predators, we exposed juvenile D. gigas to the oxygen levels found in the OMZ (1% O(2), 1 kPa, 10 °C) and measured metabolic rate, activity cycling patterns, swimming mode, escape jet (burst) frequency, mantle contraction frequency and strength, stroke volume and oxygen extraction efficiency. In normoxia, metabolic rate varied between 14 and 29 μmol O(2) g(-1) wet mass h(-1), depending on the level of activity. The mantle contraction frequency and strength were linearly correlated and increased significantly with activity level. Additionally, an increase in stroke volume and ventilatory volume per minute was observed, followed by a mantle hyperinflation process during high activity periods. Squid metabolic rate dropped more than 75% during exposure to hypoxia. Maximum metabolic rate was not achieved under such conditions and the metabolic scope was significantly decreased. Hypoxia changed the relationship between mantle contraction strength and frequency from linear to polynomial with increasing activity, indicating that, under hypoxic conditions, the jumbo squid primarily increases the strength of mantle contraction and does not regulate its frequency. Under hypoxia, jumbo squid also showed a larger inflation period (reduced contraction frequency) and decreased relaxed mantle diameter (shortened diffusion pathway), which optimize oxygen extraction efficiency (up to 82%/34%, without/with consideration of 60% potential skin respiration). Additionally, they breathe 'deeply', with more powerful contractions and enhanced stroke volume. This deep-breathing behavior allows them to display a stable ventilatory volume per minute, and explains the maintenance of the squid's cycling activity under such O(2) conditions. During hypoxia, the respiratory cycles were shorter in length but increased in frequency. This was accompanied by an increase in the number of escape jets during active periods and a faster switch between swimming modes. In late hypoxia (onset ~170 ± 10 min), all the ventilatory processes were significantly reduced and followed by a lethargic state, a behavior that seems closely associated with the process of metabolic suppression and enables the squid to extend its residence time in the OMZ.

Breathing frequency-independent effect of Tai Chi Chuan on autonomic modulation.

PubMed

Lu, Wan-An; Kuo, Cheng-Deng

2014-04-01

This study investigates the breathing frequency (BF)-independent effect of Tai Chi Chuan (TCC) on autonomic nervous modulation in TCC practitioners. Twenty-five TCC practitioners and 25 sedentary normal controls were recruited. The stationary heart rate variability (HRV) measures of TCC practitioners and controls were compared. The same HRV measures in TCC practitioners and among the controls, TCC practitioners before TCC and TCC practitioners 30 min after TCC were compared. In TCC practitioners, the BF, normalized high-frequency power (nHFP), and normalized very low-frequency power were significantly increased, while the normalized low-frequency power (nLFP) was significantly decreased 30 min after TCC. The BF correlated significantly and negatively with heart rate (HR), nHFP and nLFP, and correlated significantly and positively with mean RR interval (MnRR) before TCC in TCC practitioners. A slower BF is associated with a higher HR, a greater vagal modulation, and a greater combined sympatho-vagal modulation before TCC. To remove the effect of BF on HRV measures, new indices such as HR*BF, nHFP*BF, nLFP*BF, and MnRR/BF were introduced for comparison among the controls, TCC practitioners before TCC, and TCC practitioners 30 min after TCC. Thirty minutes after TCC, the MnRR/BF of TCC practitioner was smaller whereas HR*BF and nHFP*BF were greater than those before TCC. The BF-independent effects of TCC on the autonomic nervous modulation of TCC practitioners are an increase in vagal modulation and HR, and a decrease in mean RR interval. The mechanism underlying the parallel increase in HR and vagal modulation in TCC practitioners is not understood yet at present.

Heart rate variabilty changes during first week of acclimatization to 3500 m altitude in Indian military personnel.

PubMed

Bhaumik, G; Dass, D; Bhattacharyya, D; Sharma, Y K; Singh, S B

2013-01-01

Acute exposure to hypobaric hypoxia induces the changes in autonomic control of heart rate. Due to emergencies or war like conditions, rapid deployment of Indian military personnel into high altitude frequently occurs. Rapid deployment to high altitude soldiers are at risk of developing high altitude sickness. The present study was conducted to evaluate the acute exposure to high altitude hypobaric hypoxia (3500 m altitude) on the autonomic nervous control of heart rate in Indian military personnel during first week of acclimatization Indices of heart rate variability (viz; R-R interval, total power, low frequency, high frequency, ratio of low to high frequency) and pulse arterial oxygen saturation were measured at sea level and 3500m altitude. Power spectrum of heart rate variability was quantified by low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.5 Hz) widths. The ratio of LF to HF was also assessed as an index of the sympathovagal balance. Mean R-R interval decreased significantly on day 2 on induction to altitude which tended to increase on day 5. Total power (TP) decreased high altitude and tended to recover within a week. Both HF and LF power showed decrement at 3500m in comparison to sea level. The ratio of LF to HF (LF/HF) at 3500m was significantly higher at 3500m. SpO2 values decreased significantly (P < 0.05) at high altitude on day-2 which increased on day-5. We conclude that autonomic control of the heart rate measured by heart rate variability was altered on acute induction to 3500m which showed a significant decrease in parasympathetic tone and increase in sympathetic tone, then acclimatization seems to be characterized by progressive shift toward a higher parasympathetic tone.

A pilot study exploring the impact of cardiac medications on ciliary beat frequency: possible implications for clinical management.

PubMed

Loomba, Rohit S; Bhushan, Abhinav; Afolayan, Adeleye J

2018-05-03

Cilia are involved in several physiologic processes, and at least a single primary cilium can be found on nearly every cell in the human body. Various factors, such as pH, temperature, exposure to medications and toxins can impact ciliary function as is manifested by changes in the ciliary beat frequency. Those with ciliary dyskinesia may also have congenital cardiac malformations and may require care in a cardiac intensive care unit. This study investigates the effect on the ciliary beat frequency of medications frequently used in a cardiac intensive care unit. The ciliated epithelial cells were obtained via nasal swab from a relatively healthy individual. These cells were cultured for 24 h. Video microscopy was then employed to determine the ciliary beat frequency at baseline and then at 15, 30, 60 and 90 min after exposure to either normal saline (control) or one of several medications. The ciliary beat frequency at each time point was then compared to the ciliary beat frequency at the same time point in the control sample as well as the baseline value for that particular sample. Epinephrine increased the ciliary beat frequency compared to the baseline and the controls up to 30 min and then subsequently led to a significant decrease in ciliary beat frequency at 90 min. On the one hand, norepinephrine, dexmedetomidine, procainamide, propranolol and enalapril all decreased ciliary beat frequency significantly throughout the 90-min observation period. On the other hand, Milrinone significantly increased the ciliary beat frequency throughout the observation period, while heparin had no impact on ciliary beat frequency. The medications frequently used in cardiac intensive care unit impact ciliary function, with most being ciliodepressant. Further investigation is needed to determine the clinical impacts and whether these effects are exaggerated in those with ciliary dyskinesia.

The calcium-frequency response in the rat ventricular myocyte: an experimental and modelling study.

PubMed

Gattoni, Sara; Røe, Åsmund Treu; Frisk, Michael; Louch, William E; Niederer, Steven A; Smith, Nicolas P

2016-08-01

In the majority of species, including humans, increased heart rate increases cardiac contractility. This change is known as the force-frequency response (FFR). The majority of mammals have a positive force-frequency relationship (FFR). In rat the FFR is controversial. We derive a species- and temperature-specific data-driven model of the rat ventricular myocyte. As a measure of the FFR, we test the effects of changes in frequency and extracellular calcium on the calcium-frequency response (CFR) in our model and three altered models. The results show a biphasic peak calcium-frequency response, due to biphasic behaviour of the ryanodine receptor and the combined effect of the rapid calmodulin buffer and the frequency-dependent increase in diastolic calcium. Alterations to the model reveal that inclusion of Ca(2+) /calmodulin-dependent protein kinase II (CAMKII)-mediated L-type channel and transient outward K(+) current activity enhances the positive magnitude calcium-frequency response, and the absence of CAMKII-mediated increase in activity of the sarco/endoplasmic reticulum Ca(2+) -ATPase induces a negative magnitude calcium-frequency response. An increase in heart rate affects the strength of cardiac contraction by altering the Ca(2+) transient as a response to physiological demands. This is described by the force-frequency response (FFR), a change in developed force with pacing frequency. The majority of mammals, including humans, have a positive FFR, and cardiac contraction strength increases with heart rate. However, the rat and mouse are exceptions, with the majority of studies reporting a negative FFR, while others report either a biphasic or a positive FFR. Understanding the differences in the FFR between humans and rats is fundamental to interpreting rat-based experimental findings in the context of human physiology. We have developed a novel model of rat ventricular electrophysiology and calcium dynamics, derived predominantly from experimental data recorded under physiological conditions. As a measure of FFR, we tested the effects of changes in stimulation frequency and extracellular calcium concentration on the simulated Ca(2+) transient characteristics and showed a biphasic peak calcium-frequency relationship, consistent with recent observations of a shift from negative to positive FFR when approaching the rat physiological frequency range. We tested the hypotheses that (1) inhibition of Ca(2+) /calmodulin-dependent protein kinase II (CAMKII)-mediated increase in sarco/endoplasmic reticulum Ca(2+) -ATPase (SERCA) activity, (2) CAMKII modulation of SERCA, L-type channel and transient outward K(+) current activity and (3) Na(+) /K(+) pump dynamics play a significant role in the rat FFR. The results reveal a major role for CAMKII modulation of SERCA in the peak Ca(2+) -frequency response, driven most significantly by the cytosolic calcium buffering system and changes in diastolic Ca(2+) . © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Study of high performance alloy electroforming

NASA Technical Reports Server (NTRS)

Malone, G. A.

1985-01-01

More panels electroformed with intentional variations of pulse plating parameters are being made. Pulse plating frequency was noted to have a significant effect regarding mechanical properties. The use of a high pulse frequency (assuming fixed duty cycles) results in an increase in ductility and a decrease in ultimate and yield strengths. Electroforming to intermediate frequencies is being done to obtain the best possible combination of ductility and strength. Results of some tests from high frequency specimens are tabulated.

Evaluation of the in-hospital hemovigilance by introduction of the information technology-based system.

PubMed

Fujihara, Harumi; Yamada, Chiaki; Furumaki, Hiroaki; Nagai, Seiya; Shibata, Hiroki; Ishizuka, Keiko; Watanabe, Hiroko; Kaneko, Makoto; Adachi, Miwa; Takeshita, Akihiro

2015-12-01

Hemovigilance is an important aspect of transfusion medicine. However, the frequency of the adverse reactions often varies using different reporters. Recently, we have employed a new information technology (IT)-based in-hospital hemovigilance system. Here, we evaluated changes in practice after implementation of an IT-based reporting system. We compared the rate of frequency and details of blood transfusion-related adverse reactions 3 years before and after introduction of the IT-based reporting system. Contents and severity of the adverse reactions were reported in a paper-based reporting system, but input by selecting items in an IT-based reporting system. The details of adverse reactions are immediately sent to the blood transfusion unit online. After we introduced the IT-based reporting system, the reported rate of transfusion-related adverse reactions increased approximately 10-fold from 0.20% to 2.18% (p < 0.001), and frequencies of urticaria, pruritus, rash, fever (p < 0.001), hypertension (p = 0.001), tachycardia (p = 0.003), and nausea and vomiting (p = 0.010) increased significantly. Although there was no error report in the paper-based reporting, incorrect reports were observed in 90 cases (0.52%) in the IT-based reporting (p < 0.001). The advantages of IT-based reporting were: 1) a significant increase in the frequency of adverse reaction reporting and 2) a significant decrease in underreporting, although the true frequency has yet to be clarified. The disadvantage of the IT-based reporting was an increased incidence of incorrect inputs, all of which was unnoticed by the reporters. Our results showed several important points in need of monitoring after introduction of an IT-based reporting system. © 2015 AABB.

Effect of input perturbation on the performance and wake dynamics of aquatic propulsion in heaving flexible foils

NASA Astrophysics Data System (ADS)

Lehn, Andrea M.; Thornycroft, Patrick J. M.; Lauder, George V.; Leftwich, Megan C.

2017-02-01

In this paper we consider the effects of adding high-frequency, low-amplitude perturbations to a smooth sinusoidal base input signal for a heaving panel in a closed loop flow tank. Specifically, 0.1 cm amplitude sinusoidal perturbation waves with frequency fp ranging from 0.5 to 13.0 Hz are added to 1 cm heave sinusoids with base frequencies, fb, ranging from 0.5 to 3.0 Hz. Two thin foils with different flexural stiffness are heaved with the combined input signals in addition to both the high-heave and low-heave signals independently. In all cases, the foils are heaved in a recirculating water channel with an incoming velocity of Vx=10 cm/s and a Reynolds number based on the chord length of Re=17 300 . Results demonstrate that perturbations increase the net axial force, in the streamwise direction, in most cases tested (with the exception of some poor performing flexible foil cases). Most significantly, for a base frequency of 1 Hz, perturbations at 9 Hz result in a 780.7% increase in net streamwise force production. Generally, the higher the perturbation frequency, fp the more axial force generated. However, for the stiffer foil, a clear peak in net force exists at fp=9 Hz , regardless of the base frequency. For the stiffer foil, swimming efficiency at a 1 Hz flapping frequency is increased dramatically with the addition of a perturbation, with reduced efficiency increases at higher flapping frequencies. Likewise, for the flexible foil, swimming efficiency gains are greatest at the lower flapping frequencies. Perturbations alter the wake structure by increasing the vorticity magnitude and increasing the vortex shedding frequency; i.e., more, stronger vortices are produced in each flapping cycle.

Gambling frequency, gambling problems and concerned significant others of problem gamblers in Finland: cross-sectional population studies in 2007 and 2011.

PubMed

Salonen, Anne H; Alho, Hannu; Castrén, Sari

2015-05-01

This study compares past-year gambling frequency, gambling problems and concerned significant others (CSOs) of problem gamblers in Finland by age, from 2007 and 2011. We used random sample data collected in 2007 (n = 4722) and 2011 (n = 4484). The data were weighted, based on gender, age and region of residence. We measured the past-year gambling frequency using a categorical variable, while gambling severity was measured with the South Oaks Gambling Screen. We identified CSOs by a single question including seven response options. Chi-Squared and Fisher's exact tests were used. Overall, the past-year gambling frequency change was statistically significant between 2007 and 2011. Among 18-64-year-old Finnish people, the proportion of non-gamblers decreased. Yet, among 15-17-year-old respondents, non-gambling increased and gambling problems decreased. Among 18-24 year olds, the proportion of close ones with gambling problems also decreased. On the other hand, the proportion of family members with gambling problems increased among the 50-64 year olds. The increase in adult gambling participation was mainly explained by infrequent gambling. The proportion of gambling problems from the gamblers' and CSOs' perspective remained unchanged, yet significant changes were observed within age groups. The short-term changes in under-age gambling problems were desirable. Future studies should explore the adaptation and access hypotheses alongside gambling problems. © 2015 the Nordic Societies of Public Health.

The changing spectrum of primary glomerular diseases within 15 years: a survey of 3331 patients in a single Chinese centre.

PubMed

Zhou, Fu-de; Zhao, Ming-hui; Zou, Wan-zhong; Liu, Gang; Wang, Haiyan

2009-03-01

Primary glomerular disease (PGD) is the leading cause of end-stage renal disease (ESRD) in China. With the development of socioeconomic status of Chinese people in the last two decades, PGD in ESRD is intent to decrease. However, whether this affects the spectrum of PGD is not clear. The aim of the current study is to investigate the changing spectrum of PGD in China. The records of 5398 consecutive native renal biopsies performed in adults (>or=14 years of age) in our centre between 1993 and 2007 were retrospectively analysed. The criteria for renal biopsy and pathologic diagnosis were kept unchanged. The patients were grouped according to a 5-year interval, 1993-97 (period 1), 1998-2002 (period 2) and 2003-07 (period 3). Then they were divided into four groups according to age for stratified analysis: 14-24 years, 25-44 years, 45-59 years and the elderly (>or=60 years). Three thousand, three hundred and thirty-one patients were diagnosed with PGD. PGD remained the most common renal disease, accounting for 65.9%, 57.7% and 63.2% in period 1, 2 and 3, respectively, without any significant difference. The proportion of elder patients increased significantly from 0% in 1993 to 9.1% in 2007 (P < 0.001). Within 1993-97, the leading PGD was IgA nephropathy (50.7%), followed by non-IgA MsPGN (19.9%), membranous nephropathy (MN) (13.3%) and minimal change disease (MCD) (6.3%), while within 2003-07, the most common PGD was still IgAN (58.2%), but followed by MN (14.3%), MCD (13.4%) and non-IgA MsPGN (7.0%). The age-adjusted frequency of IgAN and MCD increased significantly from period 1 to period 3 (P < 0.01 and P < 0.001, respectively), while that of non-IgA MsPGN, EnPGN and MPGN decreased significantly (P < 0.001, P < 0.01 and P < 0.05, respectively). There was no significant change in the age-adjusted frequency of FSGS, MN and CreGN during the study period. However, when patients were stratified by age, a sixfold increase in frequency of FSGS was identified in the 14- to 24-year group (P < 0.01). The spectrum of primary glomerulonephritis has changed within the last 15 years. The relative frequency of non-IgA MsPGN, EnPGN and MPGN decreased significantly, while that of MCD and IgA nephropathy increased significantly. The relative frequency of FSGS increased significantly in younger patients.

[Effects of electromagnetic radiation on health and immune function of operators].

PubMed

Li, Yan-zhong; Chen, Shao-hua; Zhao, Ke-fu; Gui, Yun; Fang, Si-xin; Xu, Ying; Ma, Zi-jian

2013-08-01

To investigate the effects of electromagnetic radiation on the physiological indices and immune function of operators. The general conditions and electromagnetic radiation awareness rate of 205 operators under electromagnetic radiation were evaluated using a self-designed questionnaire. Physical examination, electrocardiography, and routine urine test were performed in these operators. Peripheral blood was collected from the operators under electromagnetic radiation for blood cell counting and biochemical testing, and their peripheral blood lymphocytes were cultured for determination of chromosomal aberrant frequency and micronucleus frequency. The data from these operators (exposure group) were compared with those of 95 ordinary individuals (control group). The chief complaint of giddiness, tiredness, dizziness, and amnesia showed significant differences between the exposure group and control group (P < 0.01), and the difference in headache became larger with an increase in working years. The awareness rate of electromagnetic radiation damage was significantly higher in the exposure group than in the control group. The difference in bradycardia was significant between the two groups (P <0.01), and the incidence was higher with longer working years. Significant differences between the two groups were also found in the numbers of individuals with elevated alanine aminotransferase, total bilirubin, and direct bilirubin (P < 0.01), populations with increased lymphocyte ratio and decreased neutrophil ratio (P < 0.01), populations with positive occult blood, urobilinogen, and bilirubin tests, and the number of individuals with increased micronucleus frequency of cultured peripheral blood lymphocytes (P < 0.01). In addition, the exposure group had significantly increased complement C3 and C4 (P < 0.01), significantly increased IgG (P < 0.05), and significantly decreased IgM (P < 0.01), as compared with the control group. Electromagnetic radiation may lead to the changes in physiological indices, genetic effects, and immune function and affect the health and immune function in operators. The adverse effects are increased as the working years increase. So it is important to strengthen occupational protection of operators under electromagnetic radiation.

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.

Detection of frequency-mode-shift during thermoacoustic combustion oscillations in a staged aircraft engine model combustor

NASA Astrophysics Data System (ADS)

Kobayashi, Hiroaki; Gotoda, Hiroshi; Tachibana, Shigeru; Yoshida, Seiji

2017-12-01

We conduct an experimental study using time series analysis based on symbolic dynamics to detect a precursor of frequency-mode-shift during thermoacoustic combustion oscillations in a staged aircraft engine model combustor. With increasing amount of the main fuel, a significant shift in the dominant frequency-mode occurs in noisy periodic dynamics, leading to a notable increase in oscillation amplitudes. The sustainment of noisy periodic dynamics during thermoacoustic combustion oscillations is clearly shown by the multiscale complexity-entropy causality plane in terms of statistical complexity. A modified version of the permutation entropy allows us to detect a precursor of the frequency-mode-shift before the amplification of pressure fluctuations.

Evaluation of the Children's Eating Habits Questionnaire used in the IDEFICS study by relating urinary calcium and potassium to milk consumption frequencies among European children.

PubMed

Huybrechts, I; Börnhorst, C; Pala, V; Moreno, L A; Barba, G; Lissner, L; Fraterman, A; Veidebaum, T; Hebestreit, A; Sieri, S; Ottevaere, C; Tornaritis, M; Molnár, D; Ahrens, W; De Henauw, S

2011-04-01

Measuring dietary intake in children is notoriously difficult. Therefore, it is crucial to evaluate the performance of dietary intake assessment methods in children. Given the important contribution of milk consumption to calcium (Ca) and potassium (K) intakes, urinary calcium (UCa) and potassium (UK) excretions in spot urine samples could be used for estimating correlations with milk consumption frequencies. The aim of this study was to evaluate the assessment of milk consumption frequencies derived from the Food Frequency Questionnaire section of the Children's Eating Habits Questionnaire (CEHQ-FFQ) used in the IDEFICS (Identification and prevention of dietary- and lifestyle induced health effects in children and infants) study by comparing with UCa and UK excretions in spot urine samples. This study was conducted as a setting-based community-oriented intervention study and results from the first cross-sectional survey have been included in the analysis. A total of 10,309 children aged 2-10 years from eight European countries are included in this analysis. UCa and UK excretions were measured in morning spot urine samples. Calcium and potassium urine concentrations were standardised for urinary creatinine (Cr) excretion. Ratios of UCa/Cr and UK/Cr were used for multivariate regression analyses after logarithmic transformation to obtain normal distributions of data. Milk consumption frequencies were obtained from the CEHQ-FFQ. Multivariate regression analyses were used to investigate the effect of milk consumption frequencies on UCa and UK concentrations, adjusting for age, gender, study centre, soft drink consumption and frequency of main meals consumed at home. A significant positive correlation was found between milk consumption frequencies and ratios of UK/Cr and a weaker but still significant positive correlation with ratios of UCa/Cr, when using crude or partial Spearman's correlations. Multivariate regression analyses showed that milk consumption frequencies were predictive of UCa/Cr and UK/Cr ratios, when adjusted for age, gender, study centre, soft drink consumption and frequency of main meals consumed at home. Mean ratios of UK/Cr for increasing milk consumption frequency tertiles showed a progressive increase in UK/Cr. Children consuming at least two milk servings per day had significantly higher mean UCa/Cr and UK/Cr ratios than children who did not. Large differences in correlations between milk consumption frequencies and ratios of UCa/Cr and UK/Cr were found between the different study centres. Higher milk consumption frequencies resulted in a progressive increase in UK/Cr and UCa/Cr ratios, reflecting the higher Ca and K intakes that coincide with increasing milk consumption, which constitutes a major K and Ca source in children's diet.

Skin-homing interleukin-4 and -13-producing cells contribute to bullous pemphigoid: remission of disease is associated with increased frequency of interleukin-10-producing cells.

PubMed

Teraki, Y; Hotta, T; Shiohara, T

2001-11-01

Although evidence is accumulating that type 2 cytokines play a part in the pathogenesis of bullous pemphigoid, little information is available concerning characterization of the cellular source of these cytokines involved in the pathogenesis of bullous pemphigoid. By using multiparameter flow cytometry, we investigated T cells capable of producing interleukin-2, -4, -10, and -13, interferon-gamma, and tumor necrosis factor-alpha and their correlated expression of skin-homing receptor (cutaneous lymphocyte-associated antigen) in peripheral blood and skin blister of patients with bullous pemphigoid. In peripheral blood of bullous pemphigoid patients, significantly increased frequencies of interleukin-4- and interleukin-13-producing cells were found as compared with those of healthy controls, and the majority of these type 2 cells was found in the cutaneous lymphocyte-associated antigen-positive population. The frequency of interferon-gamma-producing cells was also increased as compared with healthy subjects; however, the majority of this subset was found in the cutaneous lymphocyte-associated antigen-negative population. In the skin blister, the frequencies of interleukin-13- and interleukin-4-producing cells were much higher than those in the peripheral blood of bullous pemphigoid, whereas that of interferon-gamma producing cells was significantly lower. Furthermore, in bullous pemphigoid patients after therapy with systemic corticosteroids, the frequency of cutaneous lymphocyte-associated antigen-positive, but not cutaneous lymphocyte-associated antigen-negative, interleukin-13-producing cells was significantly decreased accompanied by an increased frequency of interleukin-10-producing cells, which was associated with clinical improvement. Thus, our results suggest that bullous pemphigoid is a unique organ-specific autoimmune disease characterized by an expansion of skin-homing interleukin-13-producing cells. In addition, corticosteroids may control such type 2 biased inflammatory responses in bullous pemphigoid by promoting the expansion of interleukin-10-producing cells.

[Effect of weather on odontogenic abscesses].

PubMed

Nissen, G; Schmidseder, R

1978-11-01

An increased frequency of odontogenous abcesses was observed on certain days in the course of routine clinical practice. We therefore investigated the possibility of a statistically significant weather-related odontogenous soft-tissue purulence originating from chronic apical periodontitis. Medical reports of patients treated between 1970 and 1977 were used. Our study indicated that the frequency of odontogenous abcesses was significantly higher with cyclonic weather conditions, i.e., weather with low barometric pressure.

Risk of mental health problems in adolescents skipping meals: The Korean National Health and Nutrition Examination Survey 2010 to 2012.

PubMed

Lee, Gyungjoo; Han, Kyungdo; Kim, Hyunju

Adolescents frequently skip meals, doing so even more than once per day. This is associated with more mental health problems. This study identified mental health problems' associations with skipping meals and the frequency thereof among adolescents. This cross-sectional population-based study used a data set of 1,413 adolescents from the 2010 to 2012 Korean National Health and Nutrition Examination Survey. Hierarchical multivariable logistic regression was conducted to determine the risk of mental health problems, including stress, depressive mood, and suicidal ideation in relation to skipping meals and the frequency thereof per day. Breakfast skipping significantly increased the risks of stress and depressive mood. Stress, depressive mood, and suicidal ideation were significantly prevalent as the daily frequency of skipping meals increased. Specific strategies should be developed at government or school level to decrease the frequency of skipping meals per day, associated with serious mental health problems in adolescents. Copyright © 2017 Elsevier Inc. All rights reserved.

Increased micronucleus, nucleoplasmic bridge, and nuclear bud frequencies in the peripheral blood lymphocytes of diesel engine exhaust-exposed workers.

PubMed

Zhang, Xiao; Duan, Huawei; Gao, Feng; Li, Yuanyuan; Huang, Chuanfeng; Niu, Yong; Gao, Weimin; Yu, Shanfa; Zheng, Yuxin

2015-02-01

The International Agency for Research on Cancer has recently reclassified diesel engine exhaust (DEE) as a Group 1 carcinogen. Micronucleus (MN), nucleoplasmic bridge (NPB), and nuclear bud (NBUD) frequencies in peripheral blood lymphocytes (PBLs) are associated with cancer risk. However, the impact of DEE exposure on MN frequency has not been thoroughly elucidated due to mixed exposure and its impact on NPB and NBUD frequencies has never been explored in humans. We recruited 117 diesel engine testing workers with exclusive exposure to DEE and 112 non-DEE-exposed workers, and then we measured urinary levels of 4 mono-hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) using high-performance liquid chromatography-mass spectrometry as well as MN, NPB, and NBUD frequencies in PBLs using cytokinesis-block MN assay. The DEE-exposed workers exhibited significantly higher MN, NPB, and NBUD frequencies than the non-DEE-exposed workers (P < 0.05). Among all study subjects, increasing levels of all 4 urinary OH-PAHs, on both quartile and continuous scales, were associated with increased MN, NPB, and NBUD frequencies (all P < 0.05). When the associations were analyzed separately in DEE-exposed and non-DEE-exposed workers, we found that the association between increasing quartiles of urinary 9-hydroxyphenanthrene (9-OHPh) and MN frequencies persisted in DEE-exposed workers (P = 0.001). The percent of MN frequencies increased, on average, by 23.99% (95% confidential interval, 9.64-39.93) per 1-unit increase in ln-transformed 9-OHPh. Our results clearly show that exposure to DEE can induce increases in MN, NPB, and NBUD frequencies in PBLs and suggest that DEE exposure level is associated with MN frequencies. © The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Non-linear HRV indices under autonomic nervous system blockade.

PubMed

Bolea, Juan; Pueyo, Esther; Laguna, Pablo; Bailón, Raquel

2014-01-01

Heart rate variability (HRV) has been studied as a non-invasive technique to characterize the autonomic nervous system (ANS) regulation of the heart. Non-linear methods based on chaos theory have been used during the last decades as markers for risk stratification. However, interpretation of these nonlinear methods in terms of sympathetic and parasympathetic activity is not fully established. In this work we study linear and non-linear HRV indices during ANS blockades in order to assess their relation with sympathetic and parasympathetic activities. Power spectral content in low frequency (0.04-0.15 Hz) and high frequency (0.15-0.4 Hz) bands of HRV, as well as correlation dimension, sample and approximate entropies were computed in a database of subjects during single and dual ANS blockade with atropine and/or propranolol. Parasympathetic blockade caused a significant decrease in the low and high frequency power of HRV, as well as in correlation dimension and sample and approximate entropies. Sympathetic blockade caused a significant increase in approximate entropy. Sympathetic activation due to postural change from supine to standing caused a significant decrease in all the investigated non-linear indices and a significant increase in the normalized power in the low frequency band. The other investigated linear indices did not show significant changes. Results suggest that parasympathetic activity has a direct relation with sample and approximate entropies.

Does ammonia trigger hyperventilation in the elasmobranch, Squalus acanthias suckleyi?

PubMed

De Boeck, Gudrun; Wood, Chris M

2015-01-15

We examined the ventilatory response of the spiny dogfish, to elevated internal or environmental ammonia. Sharks were injected via arterial catheters with ammonia solutions or their Na salt equivalents sufficient to increase plasma total ammonia concentration [TAmm]a by 3-5 fold from 145±21μM to 447±150μM using NH4HCO3 and a maximum of 766±100μM using (NH4)2SO4. (NH4)2SO4 caused a small increase in ventilation frequency (+14%) and a large increase in amplitude (+69%), while Na2SO4 did not. However, CO2 partial pressure (PaCO2) also increased and arterial pHa and plasma bicarbonate concentration ([HCO3(-)]a) decreased. NH4HCO3 caused a smaller increase in plasma ammonia resulting in a smaller but significant, short lived increases in ventilation frequency (+6%) and amplitude (36%), together with a rise in PaCO2 and [HCO3(-)]a. Injection with NaHCO3 which increased pHa and [HCO3(-)]a did not change ventilation. Plasma ammonia concentration correlated significantly with ventilation amplitude, while ventilation frequency showed a (negative) correlation with pHa. Exposure to high environmental ammonia (1500μM NH4HCO3) did not induce changes in ventilation until plasma [TAmm]a increased and ventilation amplitude (but not frequency) increased in parallel. We conclude that internal ammonia stimulates ventilation in spiny dogfish, especially amplitude or stroke volume, while environmental ammonia only stimulates ventilation after ammonia diffuses into the bloodstream. Copyright © 2014 Elsevier B.V. All rights reserved.

High-frequency gamma activity (80-150 Hz) is increased in human cortex during selective attention

PubMed Central

Ray, Supratim; Niebur, Ernst; Hsiao, Steven S.; Sinai, Alon; Crone, Nathan E.

2008-01-01

Objective: To study the role of gamma oscillations (>30 Hz) in selective attention using subdural electrocorticography (ECoG) in humans. Methods: We recorded ECoG in human subjects implanted with subdural electrodes for epilepsy surgery. Sequences of auditory tones and tactile vibrations of 800 ms duration were presented asynchronously, and subjects were asked to selectively attend to one of the two stimulus modalities in order to detect an amplitude increase at 400 ms in some of the stimuli. Results: Event-related ECoG gamma activity was greater over auditory cortex when subjects attended auditory stimuli and was greater over somatosensory cortex when subjects attended vibrotactile stimuli. Furthermore, gamma activity was also observed over prefrontal cortex when stimuli appeared in either modality, but only when they were attended. Attentional modulation of gamma power began ∼400 ms after stimulus onset, consistent with the temporal demands on attention. The increase in gamma activity was greatest at frequencies between 80 and 150 Hz, in the so-called high gamma frequency range. Conclusions: There appears to be a strong link between activity in the high-gamma range (80-150 Hz) and selective attention. Significance: Selective attention is correlated with increased activity in a frequency range that is significantly higher than what has been reported previously using EEG recordings. PMID:18037343

Effect of different head and neck positions on behaviour, heart rate variability and cortisol levels in lunged Royal Dutch Sport horses.

PubMed

Smiet, E; Van Dierendonck, M C; Sleutjens, J; Menheere, P P C A; van Breda, E; de Boer, D; Back, W; Wijnberg, I D; van der Kolk, J H

2014-10-01

Different head-and-neck positions (HNPs) are discussed in relation to potential welfare issues. To evaluate the effect on welfare, seven Royal Dutch Sport horses were studied in five predetermined HNPs: (1) unrestrained (HNP1); (2) neck raised, bridge of nose around the vertical (HNP2); (3) neck lowered and considerably flexed, bridge of nose pointing towards the chest (HNP4); (4) neck raised and extended, bridge of nose in front of the vertical (HNP5), and (5) neck lowered and flexed, bridge of nose pointing towards the carpus (HNP7). A standardised exercise test (SET) of 34 min consisted of trot, canter and walk. Behaviour was recorded with a pre-defined ethogram and R-R intervals measured using telemetry. Cortisol concentrations were taken at the start, 5 and 30 min after the SET. Behaviour around the SET was scored separately. Conflict behaviours increased significantly during HNP2 when compared with HNP1, HNP4 and HNP7 during the SET, and there was significant negative anticipation before HNP2 and HNP7. The heart rate variability (HRV) frequency domain for HNP2 showed a significantly increased low frequency peak (LFpeak) compared with other HNPs, and there was a decrease in very low frequency (VLF%) compared with HNP1. HNP4 showed a significant increase in LF% and decrease in VLF% compared with HNP1. Saliva cortisol concentrations were significantly increased in HNP2 at 5 and 30 min after exercise. Increased conflict behaviour was mostly observed in HNP2, but there was a raised HRV suggesting a sympathetic shift in HNP2 and HNP4, and increased cortisol concentrations during HNP2 indicated a stress response. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of Shift Work on Nocturia.

PubMed

Kim, Jin Wook

2016-01-01

To identify the circadian sensitive component of nocturia by comparing nocturia in patients who voluntarily choose a disrupted circadian rhythm, that is, shift workers, with those who maintain normal day-night cycles. Between 2011 and 2013, a total of 1741 untreated patients, 1376 nonshift workers and 365 shift workers, were compared for nocturia indices based on frequency volume charts (FVCs). General linear model of 8-hour interval urine production and frequency were compared between FVCs of nonshift workers, FVCs of night-shift workers, and FVCs of day-shift workers. Nocturia frequency was increased in the night-shift workers (2.38 ± 1.44) compared with nonshift workers (2.18 ± 1.04) (P <.01). Whereas nocturnal polyuria index did not increase significantly (0.33 ± 0.19 for night-shift workers, 0.34 ± 0.13 for nonshift workers, P = .24), nocturnal bladder capacity index increased significantly (1.41 ± 1.06 for night-shift workers, 1.26 ± 0.92 for nonshift workers, P <.01). Eight-hour interval indices show that urine production changed with shift (P <.01), whereas voiding frequency remains unchanged despite shift changes (P = .35). Patients in alternating work shifts showed increased nocturia, especially during their night shift. These changes tended to be more associated with decreased nocturnal bladder capacity than increased nocturnal polyuria. Copyright © 2015 Elsevier Inc. All rights reserved.

High-NaCl diet impairs dynamic renal blood flow autoregulation in rats with adenine-induced chronic renal failure.

PubMed

Saeed, Aso; DiBona, Gerald F; Grimberg, Elisabeth; Nguy, Lisa; Mikkelsen, Minne Line Nedergaard; Marcussen, Niels; Guron, Gregor

2014-03-15

This study examined the effects of 2 wk of high-NaCl diet on kidney function and dynamic renal blood flow autoregulation (RBFA) in rats with adenine-induced chronic renal failure (ACRF). Male Sprague-Dawley rats received either chow containing adenine or were pair-fed an identical diet without adenine (controls). After 10 wk, rats were randomized to either remain on the same diet (0.6% NaCl) or to be switched to high 4% NaCl chow. Two weeks after randomization, renal clearance experiments were performed under isoflurane anesthesia and dynamic RBFA, baroreflex sensitivity (BRS), systolic arterial pressure variability (SAPV), and heart rate variability were assessed by spectral analytical techniques. Rats with ACRF showed marked reductions in glomerular filtration rate and renal blood flow (RBF), whereas mean arterial pressure and SAPV were significantly elevated. In addition, spontaneous BRS was reduced by ∼50% in ACRF animals. High-NaCl diet significantly increased transfer function fractional gain values between arterial pressure and RBF in the frequency range of the myogenic response (0.06-0.09 Hz) only in ACRF animals (0.3 ± 4.0 vs. -4.4 ± 3.8 dB; P < 0.05). Similarly, a high-NaCl diet significantly increased SAPV in the low-frequency range only in ACRF animals. To conclude, a 2-wk period of a high-NaCl diet in ACRF rats significantly impaired dynamic RBFA in the frequency range of the myogenic response and increased SAPV in the low-frequency range. These abnormalities may increase the susceptibility to hypertensive end-organ injury and progressive renal failure by facilitating pressure transmission to the microvasculature.

Effects of GSM-Frequency Electromagnetic Radiation on Some Physiological and Biochemical Parameters in Rats.

PubMed

Khirazova, E E; Baizhumanov, A A; Trofimova, L K; Deev, L I; Maslova, M V; Sokolova, N A; Kudryashova, N Yu

2012-10-01

Single exposure of white outbred rats to electromagnetic radiation with a frequency 905 MHz (GSM frequency) for 2 h increased anxiety, reduced locomotor, orientation, and exploration activities in females and orientation and exploration activities in males. Glucocorticoid levels and antioxidant system activity increased in both males and females. In addition to acute effects, delayed effects of radiation were observed in both males and females 1 day after the exposure. These results demonstrated significant effect of GSM-range radiation on the behavior and activity of stress-realizing and stress-limiting systems of the body.

Differentiating Adolescent Suicide Attempters from Ideators: Examining the Interaction between Depression Severity and Alcohol Use

PubMed Central

McManama O’Brien, Kimberly H.; Becker, Sara J.; Spirito, Anthony; Simon, Valerie; Prinstein, Mitchell J.

2014-01-01

This study examined whether depressed mood, frequency of alcohol use, and their combination differentiated non-suicidal adolescents from those with suicidal ideation and adolescents with suicidal ideation from those who have made a suicide attempt. Hierarchical logistic regressions indicated that frequency of alcohol use did not differentiate non-suicidal adolescents from those with current suicidal ideation, but severity of depressed mood did so. In contrast, alcohol use was a significant differentiating factor between adolescents who had attempted suicide compared to those with suicidal ideation only, with severity of depressed mood not being significant. However, there was also a significant interaction effect such that for adolescents with suicidal ideation and low levels of depression, increased frequency of alcohol use was associated with increased odds of a suicide attempt. These findings suggest that alcohol use may hasten the transition from suicidal ideation to suicide attempt in adolescents with low levels of depressed mood. PMID:23889515

Heart-rate variability and precompetitive anxiety in swimmers.

PubMed

Cervantes Blásquez, Julio César; Rodas Font, Gil; Capdevila Ortís, Lluís

2009-11-01

The aim of this study was to test the utility of heart-rate variability (HRV) analyses as a noninvasive means of quantifying cardiac autonomic regulation during precompetitive anxiety situations in swimmers. Psychophysiological state evaluation of 10 volunteer swimmers (6 women and 4 men) was obtained by comparing baseline training condition (TC) with competition condition (CC). Self-evaluation of precompetitive somatic anxiety measured by CSAI-2 showed significant increase from the TC to CC. Analysis showed that during higher precompetitive anxiety level, a significant reduction in the timing (RMSSD), frequency (HFms2 and HFnu) and Poincaré plot (SD1) of heart-rate variability was observed, and a significant increase in the low frequency to high frequency ratio (LF/HF %). The results indicate a shift towards sympathetic predominance as a result of parasympathetic withdrawal. Our results provide an HRV analysis in a valid, useful and non-invasive way to evaluate the change of sympathovagal balance in presence of precompetitive stress.

Micronuclei in cord blood lymphocytes and associations with biomarkers of exposure to carcinogens and hormonally active factors, gene polymorphisms, and gene expression: the NewGeneris cohort.

PubMed

Merlo, Domenico Franco; Agramunt, Silvia; Anna, Lívia; Besselink, Harrie; Botsivali, Maria; Brady, Nigel J; Ceppi, Marcello; Chatzi, Leda; Chen, Bowang; Decordier, Ilse; Farmer, Peter B; Fleming, Sarah; Fontana, Vincenzo; Försti, Asta; Fthenou, Eleni; Gallo, Fabio; Georgiadis, Panagiotis; Gmuender, Hans; Godschalk, Roger W; Granum, Berit; Hardie, Laura J; Hemminki, Kari; Hochstenbach, Kevin; Knudsen, Lisbeth E; Kogevinas, Manolis; Kovács, Katalin; Kyrtopoulos, Soterios A; Løvik, Martinus; Nielsen, Jeanette K; Nygaard, Unni Cecilie; Pedersen, Marie; Rydberg, Per; Schoket, Bernadette; Segerbäck, Dan; Singh, Rajinder; Sunyer, Jordi; Törnqvist, Margareta; van Loveren, Henk; van Schooten, Frederik J; Vande Loock, Kim; von Stedingk, Hans; Wright, John; Kleinjans, Jos C; Kirsch-Volders, Micheline; van Delft, Joost H M

2014-02-01

Leukemia incidence has increased in recent decades among European children, suggesting that early-life environmental exposures play an important role in disease development. We investigated the hypothesis that childhood susceptibility may increase as a result of in utero exposure to carcinogens and hormonally acting factors. Using cord blood samples from the NewGeneris cohort, we examined associations between a range of biomarkers of carcinogen exposure and hormonally acting factors with micronuclei (MN) frequency as a proxy measure of cancer risk. Associations with gene expression and genotype were also explored. DNA and protein adducts, gene expression profiles, circulating hormonally acting factors, and GWAS (genome-wide association study) data were investigated in relation to genomic damage measured by MN frequency in lymphocytes from 623 newborns enrolled between 2006 and 2010 across Europe. Malondialdehyde DNA adducts (M1dG) were associated with increased MN frequency in binucleated lymphocytes (MNBN), and exposure to androgenic, estrogenic, and dioxin-like compounds was associated with MN frequency in mononucleated lymphocytes (MNMONO), although no monotonic exposure-outcome relationship was observed. Lower frequencies of MNBN were associated with a 1-unit increase expression of PDCD11, LATS2, TRIM13, CD28, SMC1A, IL7R, and NIPBL genes. Gene expression was significantly higher in association with the highest versus lowest category of bulky and M1dG-DNA adducts for five and six genes, respectively. Gene expression levels were significantly lower for 11 genes in association with the highest versus lowest category of plasma AR CALUX® (chemically activated luciferase expression for androgens) (8 genes), ERα CALUX® (for estrogens) (2 genes), and DR CALUX® (for dioxins). Several SNPs (single-nucleotide polymorphisms) on chromosome 11 near FOLH1 significantly modified associations between androgen activity and MNBN frequency. Polymorphisms in EPHX1/2 and CYP2E1 were associated with MNBN. We measured in utero exposure to selected environmental carcinogens and circulating hormonally acting factors and detected associations with MN frequency in newborns circulating T lymphocytes. The results highlight mechanisms that may contribute to carcinogen-induced leukemia and require further research.

Micronucleus frequency in women with genital Chlamydia Trachomatis infection before and after therapy.

PubMed

Dimitrijević, A; Milosević-Djordjević, O; Grujicić, D; Arsenijević, S

2006-09-19

The main aim of the present study was to investigate the influence of infection with the intracellular bacterium Chlamydia trachomatis, and subsequent treatments with oral doxycycline or azithromycin on the frequency of micronuclei (MN) in peripheral blood lymphocytes of adult female patients receiving standard doses of these drugs. The frequency of micronuclei was measured in the lymphocytes of 38 newly diagnosed adult women with genital C. trachomatis infection. Samples were taken before and after the therapy, and from 50 healthy control females. The therapy was taken orally during 10 days at 2 x 100 mg per day, and then for another 10 days at 1 x 100 mg per day for doxycycline, and as a single dose of 1g for azithromycin. Isolated lymphocytes from all subjects were cultured by use of the whole-blood method and blocked in metaphase with cytochalasin B (Cyt B). One thousand binucleate cells per subject were scored according to published criteria. The frequency of micronuclei was not significantly higher in samples of infected females before therapy, compared with the baseline frequency in healthy control females (p > 0.05). In patients who received doxycycline, the micronucleus frequency after the end of therapy was significantly higher than before treatment (p < 0.001). The mean frequency of micronuclei in females after the end of the therapy with azithromycin did not show an increase (p > 0.05). The application of linear regression analysis showed that the difference in micronucleus frequency before and after therapy (effect of the antibiotics) was affected by the therapy type. Age and smoking did not affect micronucleus frequency in analyzed samples of patients (p = 0.078, 0.579). We conclude that C. trachomatis infection does not induce micronuclei in peripheral blood lymphocytes of infected adult female patients. Therapy with doxycycline significantly increases the micronucleus frequency in lymphocytes of treated patients, but treatment with azithromycin does not induce micronuclei.

Nocturnal polyuria and decreased serum testosterone: is there an association in men with lower urinary tract symptoms?

PubMed

Kim, Jin Wook; Oh, Mi Mi; Yoon, Cheol Yong; Bae, Jae Hyun; Kim, Je Jong; Moon, Du Geon

2014-05-01

To investigate the putative association between nocturia and decreased serum testosterone in men with lower urinary tract symptoms. Frequency volume charts and serum testosterone levels of patients visiting the outpatient clinic for lower urinary tract symptoms were collected and analyzed. Age, prostate volume, body mass index and the presence of comorbidities were accounted for. Frequency volume charts were analyzed for pathophysiological components of nocturnal polyuria, global polyuria, decreased nocturnal bladder capacity and increased frequency to identify associated risks. Frequency volume charts were also used to chart 8-h changes of volume, frequency and capacity to identify time diurnal interactions with risk factors based on serum testosterone levels. A total of 2180 patients were enrolled in the study. Multivariate analysis showed testosterone decreased 0.142 ng/mL for every increase in nocturia, independent of other factors. Logistic regression analysis showed a significant difference between pathophysiological components. Decreased testosterone was shown to carry a significant independent risk for overall nocturia (odds ratio 1.60, 95% confidence interval 1.013-2.527, P = 0.044), and particularly nocturnal polyuria (odds ratio 1.934, 95% confidence interval 1.001-3.737, P = 0.027). Repeated measurement models showed patients with serum testosterone below 2.50 ng/mL to have a paradoxical increase in nocturnal urine volume at night. Nocturia, especially nocturnal polyuria, is associated with decreased serum testosterone. Patients with low serum testosterone show increased nocturnal urine output. © 2013 The Japanese Urological Association.

Peculiarities of the third natural frequency vibrations of a cantilever for the improvement of energy harvesting.

PubMed

Ostasevicius, Vytautas; Janusas, Giedrius; Milasauskaite, Ieva; Zilys, Mindaugas; Kizauskiene, Laura

2015-05-28

This paper focuses on several aspects extending the dynamical efficiency of a cantilever beam vibrating in the third mode. A few ways of producing this mode stimulation, namely vibro-impact or forced excitation, as well as its application for energy harvesting devices are proposed. The paper presents numerical and experimental analyses of novel structural dynamics effects along with an optimal configuration of the cantilever beam. The peculiarities of a cantilever beam vibrating in the third mode are related to the significant increase of the level of deformations capable of extracting significant additional amounts of energy compared to the conventional harvester vibrating in the first mode. Two types of a piezoelectric vibrating energy harvester (PVEH) prototype are analysed in this paper: the first one without electrode segmentation, while the second is segmented using electrode segmentation at the strain nodes of the third vibration mode to achieve effective operation at the third resonant frequency. The results of this research revealed that the voltage generated by any segment of the segmented PVEH prototype excited at the third resonant frequency demonstrated a 3.4-4.8-fold increase in comparison with the non-segmented prototype. Simultaneously, the efficiency of the energy harvester prototype also increased at lower resonant frequencies from 16% to 90%. The insights presented in the paper may serve for the development and fabrication of advanced piezoelectric energy harvesters which would be able to generate a considerably increased amount of electrical energy independently of the frequency of kinematical excitation.

Low-frequency stimulation of the external globus palladium produces anti-epileptogenic and anti-ictogenic actions in rats.

PubMed

Cheng, Hui; Kuang, Yi-fang; Liu, Yang; Wang, Yi; Xu, Zheng-hao; Gao, Feng; Zhang, Shi-hong; Ding, Mei-ping; Chen, Zhong

2015-08-01

To investigate the anti-epileptic effects of deep brain stimulation targeting the external globus palladium (GPe) in rats. For inducing amygdala kindling and deep brain stimulation, bipolar stainless-steel electrodes were implanted in SD rats into right basolateral amygdala and right GPe, respectively. The effects of deep brain stimulation were evaluated in the amygdala kindling model, maximal electroshock model (MES) and pentylenetetrazole (PTZ) model. Moreover, the background EEGs in the amygdala and GPe were recorded. Low-frequency stimulation (0.1 ms, 1 Hz, 15 min) at the GPe slowed the progression of seizure stages and shortened the after-discharge duration (ADD) during kindling acquisition. Furthermore, low-frequency stimulation significantly decreased the incidence of generalized seizures, suppressed the average stage, and shortened the cumulative ADD and generalized seizure duration in fully kindled rats. In addition, low-frequency stimulation significantly suppressed the average stage of MES-induced seizures and increased the latency to generalized seizures in the PTZ model. High-frequency stimulation (0.1 ms, 130 Hz, 5 min) at the GPe had no anti-epileptic effect and even aggravated epileptogenesis induced by amygdala kindling. EEG analysis showed that low-frequency stimulation at the GPe reversed the increase in delta power, whereas high-frequency stimulation at the GPe had no such effect. Low-frequency stimulation, but not high-frequency stimulation, at the GPe exerts therapeutic effect on temporal lobe epilepsy and tonic-colonic generalized seizures, which may be due to interference with delta rhythms. The results suggest that modulation of GPe activity using low-frequency stimulation or drugs may be a promising epilepsy treatment.

Wide-bandwidth, wide-beamwidth, high-resolution, millimeter-wave imaging for concealed weapon detection

NASA Astrophysics Data System (ADS)

Sheen, David M.; Fernandes, Justin L.; Tedeschi, Jonathan R.; McMakin, Douglas L.; Jones, A. Mark; Lechelt, Wayne M.; Severtsen, Ronald H.

2013-05-01

Active millimeter-wave imaging is currently being used for personnel screening at airports and other high-security facilities. The cylindrical imaging techniques used in the deployed systems are based on licensed technology developed at the Pacific Northwest National Laboratory. The cylindrical and a related planar imaging technique form three-dimensional images by scanning a diverging beam swept frequency transceiver over a two-dimensional aperture and mathematically focusing or reconstructing the data into three-dimensional images of the person being screened. The resolution, clothing penetration, and image illumination quality obtained with these techniques can be significantly enhanced through the selection of the aperture size, antenna beamwidth, center frequency, and bandwidth. The lateral resolution can be improved by increasing the center frequency, or it can be increased with a larger antenna beamwidth. The wide beamwidth approach can significantly improve illumination quality relative to a higher frequency system. Additionally, a wide antenna beamwidth allows for operation at a lower center frequency resulting in less scattering and attenuation from the clothing. The depth resolution of the system can be improved by increasing the bandwidth. Utilization of extremely wide bandwidths of up to 30 GHz can result in depth resolution as fine as 5 mm. This wider bandwidth operation may allow for improved detection techniques based on high range resolution. In this paper, the results of an extensive imaging study that explored the advantages of using extremely wide beamwidth and bandwidth are presented, primarily for 10-40 GHz frequency band.

Computer-aided design comparisons of monolithic and hybrid MEM-tunable VCSELs

NASA Astrophysics Data System (ADS)

Ochoa, Edward M.; Nelson, Thomas R., Jr.; Blum-Spahn, Olga; Lott, James A.

2003-07-01

We report and use our micro-electro-mechanically tunable vertical cavity surface emitting laser (MEM-TVCSEL) computer-aided design methodology to investigate the resonant frequency design space for monolithic and hybrid MEM-TVCSELs. For various initial optical air gap thickness, we examine the sensitivity of monolithic or hybrid MEM-TVCSEL resonant frequency by simulating zero, two, and four percent variations in III-V material growth thickness. As expected, as initial optical airgap increases, tuning range decreases due to less coupling between the active region and the tuning mirror. However, each design has different resonant frequency sensitivity to variations in III-V growth parameters. In particular, since the monolithic design is comprised of III-V material, the shift in all growth thicknesses significantly shifts the resonant frequency response. However, for hybrid MEMTVCSELs, less shift results, since the lower reflector is an Au mirror with reflectivity independent of III-V growth variations. Finally, since the hybrid design is comprised of a MUMPS polysilicon mechanical actuator, pull-in voltage remains independent of the initial optical airgap between the tuning reflector and the III-V material. Conversely, as the initial airgap increases in the monolithic design, the pull-in voltage significantly increases.

Ultrasonic waste activated sludge disintegration for improving anaerobic stabilization.

PubMed

Tiehm, A; Nickel, K; Zellhorn, M; Neis, U

2001-06-01

The pretreatment of waste activated sludge by ultrasonic disintegration was studied in order to improve the anaerobic sludge stabilization. The ultrasound frequency was varied within a range from 41 to 3217 kHz. The impact of different ultrasound intensities and treatment times was examined. Sludge disintegration was most significant at low frequencies. Low-frequency ultrasound creates large cavitation bubbles which upon collapse initiate powerful jet streams exerting strong shear forces in the liquid. The decreasing sludge disintegration efficiency observed at higher frequencies was attributed to smaller cavitation bubbles which do not allow the initiation of such strong shear forces. Short sonication times resulted in sludge floc deagglomeration without the destruction of bacteria cells. Longer sonication brought about the break-up of cell walls, the sludge solids were distintegrated and dissolved organic compounds were released. The anaerobic digestion of waste activated sludge following ultrasonic pretreatment causing microbial cell lysis was significantly improved. There was an increase in the volatile solids degradation as well as an increase in the biogas production. The increase in digestion efficiency was proportional to the degree of sludge disintegration. To a lesser degree the deagglomeration of sludge flocs also augmented the anaerobic volatile solids degradation.

Evidence that ship noise increases stress in right whales

PubMed Central

Rolland, Rosalind M.; Parks, Susan E.; Hunt, Kathleen E.; Castellote, Manuel; Corkeron, Peter J.; Nowacek, Douglas P.; Wasser, Samuel K.; Kraus, Scott D.

2012-01-01

Baleen whales (Mysticeti) communicate using low-frequency acoustic signals. These long-wavelength sounds can be detected over hundreds of kilometres, potentially allowing contact over large distances. Low-frequency noise from large ships (20–200 Hz) overlaps acoustic signals used by baleen whales, and increased levels of underwater noise have been documented in areas with high shipping traffic. Reported responses of whales to increased noise include: habitat displacement, behavioural changes and alterations in the intensity, frequency and intervals of calls. However, it has been unclear whether exposure to noise results in physiological responses that may lead to significant consequences for individuals or populations. Here, we show that reduced ship traffic in the Bay of Fundy, Canada, following the events of 11 September 2001, resulted in a 6 dB decrease in underwater noise with a significant reduction below 150 Hz. This noise reduction was associated with decreased baseline levels of stress-related faecal hormone metabolites (glucocorticoids) in North Atlantic right whales (Eubalaena glacialis). This is the first evidence that exposure to low-frequency ship noise may be associated with chronic stress in whales, and has implications for all baleen whales in heavy ship traffic areas, and for recovery of this endangered right whale population. PMID:22319129

Evidence that ship noise increases stress in right whales.

PubMed

Rolland, Rosalind M; Parks, Susan E; Hunt, Kathleen E; Castellote, Manuel; Corkeron, Peter J; Nowacek, Douglas P; Wasser, Samuel K; Kraus, Scott D

2012-06-22

Baleen whales (Mysticeti) communicate using low-frequency acoustic signals. These long-wavelength sounds can be detected over hundreds of kilometres, potentially allowing contact over large distances. Low-frequency noise from large ships (20-200 Hz) overlaps acoustic signals used by baleen whales, and increased levels of underwater noise have been documented in areas with high shipping traffic. Reported responses of whales to increased noise include: habitat displacement, behavioural changes and alterations in the intensity, frequency and intervals of calls. However, it has been unclear whether exposure to noise results in physiological responses that may lead to significant consequences for individuals or populations. Here, we show that reduced ship traffic in the Bay of Fundy, Canada, following the events of 11 September 2001, resulted in a 6 dB decrease in underwater noise with a significant reduction below 150 Hz. This noise reduction was associated with decreased baseline levels of stress-related faecal hormone metabolites (glucocorticoids) in North Atlantic right whales (Eubalaena glacialis). This is the first evidence that exposure to low-frequency ship noise may be associated with chronic stress in whales, and has implications for all baleen whales in heavy ship traffic areas, and for recovery of this endangered right whale population.

Neurocysticercosis, a Persisting Health Problem in Mexico

PubMed Central

Fleury, Agnès; Moreno García, Jael; Valdez Aguerrebere, Paulina; de Sayve Durán, María; Becerril Rodríguez, Paola; Larralde, Carlos; Sciutto, Edda

2010-01-01

Background The ongoing epidemiological transition in Mexico minimizes the relative impact of neurocysticercosis (NC) on public health. However, hard data on the disease frequency are not available. Methodology All clinical records from patients admitted in the Instituto Nacional de Neurologia y Neurocirugia (INNN) at Mexico City in 1994 and 2004 were revised. The frequencies of hospitalized NC patients in neurology, neurosurgery and psychiatry services, as well as NC mortality from 1995 through 2009, were retrieved. Statistical analyses were made to evaluate possible significant differences in frequencies of NC patients' admission between 1994 and 2004, and in yearly frequencies of NC patients' hospitalization and death between 1995 and 2009. Principal Findings NC frequency in INNN is not significantly different in 1994 and 2004. Between these two years, clinical severity of the cases diminished and the proportion of patients living in Mexico City increased. Yearly frequencies of hospitalization in neurology and psychiatry services were stable, while frequencies of hospitalization in neurosurgery service and mortality significantly decreased between 1995 and 2009. Conclusions Our findings show a stable tendency of hospital cases during the last decade that should encourage to redouble efforts to control this ancient disease. PMID:20808759

X-Ray Variability Characteristics of the Seyfert 1 Galaxy NGC 3783

NASA Astrophysics Data System (ADS)

Markowitz, A.

2005-12-01

We have characterized the energy-dependent X-ray variability properties of the Seyfert 1 galaxy NGC 3783 using archival XMM-Newton and Rossi X-Ray Timing Explorer data. The high-frequency fluctuation power spectral density function (PSD) slope is consistent with flattening toward higher energies. Light-curve cross-correlation functions yield no significant lags, but peak coefficients generally decrease as energy separation of the bands increases on both short and long timescales. We have measured the coherence between various X-ray bands over the temporal frequency range of 6×10-8-1×10-4 Hz; this range includes the temporal frequency of the low-frequency PSD break tentatively detected by Markowitz et al. and includes the lowest temporal frequency over which coherence has been measured in any active galactic nucleus to date. Coherence is generally near unity at these temporal frequencies, although it decreases slightly as energy separation of the bands increases. Temporal frequency-dependent phase lags are detected on short timescales; phase lags are consistent with increasing as energy separation increases or as temporal frequency decreases. All of these results are similar to those obtained previously for several Seyfert galaxies and stellar mass black hole systems. Qualitatively, these results are consistent with the variability models of Kotov et al. and Lyubarskii, wherein the X-ray variability is due to inwardly propagating variations in the local mass accretion rate.

Effects of Alprazolam on Cortical Activity and Tremors in Patients with Essential Tremor

PubMed Central

Ibáñez, Jaime; González de la Aleja, Jesús; Gallego, Juan A.; Romero, Juan P.; Saíz-Díaz, Rosana A.; Benito-León, Julián; Rocon, Eduardo

2014-01-01

Background Essential tremor (ET) is characterised by postural and action tremors with a frequency of 4–12 Hz. Previous studies suggest that the tremor activity originates in the cerebello-thalamocortical pathways. Alprazolam is a short-acting benzodiazepine that attenuates tremors in ET. The mechanisms that mediate the therapeutic action of alprazolam are unknown; however, in healthy subjects, benzodiazepines increase cortical beta activity. In this study, we investigated the effect of alprazolam both on beta and tremor-related cortical activity and on alterations in tremor presentation in ET patients. Therefore, we characterised the dynamics of tremor and cortical activity in ET patients after alprazolam intake. Methods We recorded hand tremors and contralateral cortical activity in four recordings before and after a single dose of alprazolam. We then computed the changes in tremors, cortico-muscular coherence, and cortical activity at the tremor frequency and in the beta band. Results Alprazolam significantly attenuated tremors (EMG: 76.2±22.68%), decreased cortical activity in the tremor frequency range and increased cortical beta activity in all patients (P<0.05). At the same time, the cortico-muscular coherence at the tremor frequency became non-significant (P<0.05). We also found a significant correlation (r = 0.757, P<0.001) between the reduction in tremor severity and the increased ratio of cortical activity in the beta band to the activity observed in the tremor frequency range. Conclusions This study provides the first quantitative analysis of tremor reduction following alprazolam intake. We observed that the tremor severity decreased in association with an increased ratio of beta to tremor-related cortical activity. We hypothesise that the increase in cortical beta activity may act as a blocking mechanism and may dampen the pathological oscillatory activity, which in turn attenuates the observed tremor. PMID:24667763

Risk of cancer in an occupationally exposed cohort with increased level of chromosomal aberrations.

PubMed Central

Smerhovsky, Z; Landa, K; Rössner, P; Brabec, M; Zudova, Z; Hola, N; Pokorna, Z; Mareckova, J; Hurychova, D

2001-01-01

We used cytogenetic analysis to carry out a cohort study in which the major objective was to test the association between frequency of chromosomal aberrations and subsequent risk of cancer. In spite of the extensive use of the cytogenetic analysis of human peripheral blood lymphocytes in biomonitoring of exposure to various mutagens and carcinogens on an ecologic level, the long-term effects of an increased frequency of chromosomal aberrations in individuals are still uncertain. Few epidemiologic studies have addressed this issue, and a moderate risk of cancer in individuals with an elevated frequency of chromosomal aberrations has been observed. In the present study, we analyzed data on 8,962 cytogenetic tests and 3,973 subjects. We found a significant and strong association between the frequency of chromosomal aberrations and cancer incidence in a group of miners exposed to radon, where a 1% increase in frequency of chromosomal aberrations was followed by a 64% increase in risk of cancer (p < 0.000). In contrast, the collected data are inadequate for a critical evaluation of the association with exposure to other chemicals. PMID:11171523

Low-frequency blood pressure oscillations and inotrope treatment failure in premature infants.

PubMed

Vesoulis, Zachary A; Hao, Jessica; McPherson, Christopher; El Ters, Nathalie M; Mathur, Amit M

2017-07-01

The underlying mechanism as to why some hypotensive preterm infants do not respond to inotropic medications remains unclear. For these infants, we hypothesize that impaired vasomotor function is a significant factor and is manifested through a decrease in low-frequency blood pressure variability across regulatory components of vascular tone. Infants born ≤28 wk estimated gestational age underwent prospective recording of mean arterial blood pressure for 72 h after birth. After error correction, root-mean-square spectral power was calculated for each valid 10-min data frame across each of four frequency bands ( B1 , 0.005-0.0095 Hz; B2 , 0.0095-0.02 Hz; B3 , 0.02-0.06 Hz; and B4 , 0.06-0.16) corresponding to different components of vasomotion control. Forty infants (twenty-nine normotensive control and eleven inotrope-exposed) were included with a mean ± SD estimated gestational age of 25.2 ± 1.6 wk and birth weight 790 ± 211 g. 9.7/11.8 Million (82%) data points were error-free and used for analysis. Spectral power across all frequency bands increased with time, although the magnitude was 20% less in the inotrope-exposed infants. A statistically significant increase in spectral power in response to inotrope initiation was noted across all frequency bands. Infants with robust blood pressure response to inotropes had a greater increase compared with those who had limited or no blood pressure response. In this study, hypotensive infants who require inotropes have decreased low-frequency variability at baseline compared with normotensive infants, which increases after inotrope initiation. Low-frequency spectral power does not change for those with inotrope treatment failure, suggesting dysfunctional regulation of vascular tone as a potential mechanism of treatment failure. NEW & NOTEWORTHY In this study, we examine patterns of low-frequency oscillations in blood pressure variability across regulatory components of vascular tone in normotensive and hypotensive infants exposed to inotropic medications. We found that hypotensive infants who require inotropes have decreased low-frequency variability at baseline, which increases after inotrope initiation. Low-frequency spectral power does not change for those with inotrope treatment failure, suggesting dysfunctional regulation of vascular tone as a potential mechanism of treatment failure. Copyright © 2017 the American Physiological Society.

Effects of age, task, and frequency on variability of finger tapping.

PubMed

Sommervoll, Yngve; Ettema, Gertjan; Vereijken, Beatrix

2011-10-01

The goal was to assess whether prior studies might have overestimated performance variability in older adults in dual task conditions by relying on primary motor tasks that are not constant with aging. 30 younger and 31 older adults performed a bimanual tapping task at four different frequencies in isolation or concurrently with a secondary task. Results showed that performance of younger and older adults was not significantly different in performing the tapping task at all frequencies and with either secondary task, as indicated by mean tapping performance and low number of errors in the secondary tasks. Both groups showed increased variability as tapping frequency increased and with the presence of a secondary task. Tapping concurrently while reading words increased tapping variability more than tapping concurrently while naming colours. Although older participants' performances were overall more variable, no interaction effects with age were found and at the highest frequencies of tapping, younger and older participants did not differ in performance.

Inferior frontal sensitivity to common speech sounds is amplified by increasing word intelligibility.

PubMed

Vaden, Kenneth I; Kuchinsky, Stefanie E; Keren, Noam I; Harris, Kelly C; Ahlstrom, Jayne B; Dubno, Judy R; Eckert, Mark A

2011-11-01

The left inferior frontal gyrus (LIFG) exhibits increased responsiveness when people listen to words composed of speech sounds that frequently co-occur in the English language (Vaden, Piquado, & Hickok, 2011), termed high phonotactic frequency (Vitevitch & Luce, 1998). The current experiment aimed to further characterize the relation of phonotactic frequency to LIFG activity by manipulating word intelligibility in participants of varying age. Thirty six native English speakers, 19-79 years old (mean=50.5, sd=21.0) indicated with a button press whether they recognized 120 binaurally presented consonant-vowel-consonant words during a sparse sampling fMRI experiment (TR=8 s). Word intelligibility was manipulated by low-pass filtering (cutoff frequencies of 400 Hz, 1000 Hz, 1600 Hz, and 3150 Hz). Group analyses revealed a significant positive correlation between phonotactic frequency and LIFG activity, which was unaffected by age and hearing thresholds. A region of interest analysis revealed that the relation between phonotactic frequency and LIFG activity was significantly strengthened for the most intelligible words (low-pass cutoff at 3150 Hz). These results suggest that the responsiveness of the left inferior frontal cortex to phonotactic frequency reflects the downstream impact of word recognition rather than support of word recognition, at least when there are no speech production demands. Published by Elsevier Ltd.

Acoustic analyses of developmental changes and emotional expression in the preverbal vocalizations of infants.

PubMed

Scheiner, Elisabeth; Hammerschmidt, Kurt; Jürgens, Uwe; Zwirner, Petra

2002-12-01

The nonverbal vocal utterances of seven normally hearing infants were studied within their first year of life with respect to age- and emotion-related changes. Supported by a multiparametric acoustic analysis it was possible to distinguish one inspiratory and eleven expiratory call types. Most of the call types appeared within the first two months; some emerged in the majority of infants not until the 5th ("laugh") or 7th month ("babble"). Age-related changes in acoustic structure were found in only 4 call types ("discomfort cry," "short discomfort cry," "wail," "moan"). The acoustic changes were characterized mainly by an increase in harmonic-to-noise ratio and homogeneity of the call, a decrease in frequency range and a downward shift of acoustic energy from higher to lower frequencies. Emotion-related differences were found in the acoustic structure of single call types as well as in the frequency of occurrence of different call types. A change from positive to negative emotional state was accompanied by an increase in call duration, frequency range, and peak frequency (frequency with the highest amplitude within the power spectrum). Negative emotions, in addition, were characterized by a significantly higher rate of "crying," "hic" and "ingressive vocalizations" than positive emotions, while positive emotions showed a significantly higher rate of "babble," "laugh," and "raspberry."

Transport pathways and enhancement mechanisms within localized and non-localized transport regions in skin treated with low-frequency sonophoresis and sodium lauryl sulfate.

PubMed

Polat, Baris E; Figueroa, Pedro L; Blankschtein, Daniel; Langer, Robert

2011-02-01

Recent advances in transdermal drug delivery utilizing low-frequency sonophoresis (LFS) and sodium lauryl sulfate (SLS) have revealed that skin permeability enhancement is not homogenous across the skin surface. Instead, highly perturbed skin regions, known as localized transport regions (LTRs), exist. Despite these findings, little research has been conducted to identify intrinsic properties and formation mechanisms of LTRs and the surrounding less-perturbed non-LTRs. By independently analyzing LTR, non-LTR, and total skin samples treated at multiple LFS frequencies, we found that the pore radii (r(pore)) within non-LTRs are frequency-independent, ranging from 18.2 to 18.5 Å, but significantly larger than r(pore) of native skin samples (13.6 Å). Conversely, r(pore) within LTRs increase significantly with decreasing frequency from 161 to 276 Å and to ∞ (>300 Å) for LFS/SLS-treated skin at 60, 40, and 20 kHz, respectively. Our findings suggest that different mechanisms contribute to skin permeability enhancement within each skin region. We propose that the enhancement mechanism within LTRs is the frequency-dependent process of cavitation-induced microjet collapse at the skin surface, whereas the increased r(pore) values in non-LTRs are likely due to SLS perturbation, with enhanced penetration of SLS into the skin resulting from the frequency-independent process of microstreaming. Copyright © 2010 Wiley-Liss, Inc.

Transport Pathways and Enhancement Mechanisms within Localized and Non-Localized Transport Regions in Skin Treated with Low-Frequency Sonophoresis and Sodium Lauryl Sulfate

PubMed Central

Polat, Baris E.; Figueroa, Pedro L.; Blankschtein, Daniel; Langer, Robert

2011-01-01

Recent advances in transdermal drug delivery utilizing low-frequency sonophoresis (LFS) and sodium lauryl sulfate (SLS) have revealed that skin permeability enhancement is not homogenous across the skin surface. Instead, highly perturbed skin regions, known as localized transport regions (LTRs), exist. Despite these findings, little research has been conducted to identify intrinsic properties and formation mechanisms of LTRs and the surrounding less-perturbed non-LTRs. By independently analyzing LTR, non-LTR, and total skin samples treated at multiple LFS frequencies, we found that the pore radii (rpore) within non-LTRs are frequency-independent, ranging from 18.2 – 18.5 Å, but significantly larger than rpore of native skin samples (13.6 Å). Conversely, rpore within LTRs increases significantly with decreasing frequency from 161 Å, to 276 Å, and to ∞ (>300Å) for LFS/SLS-treated skin at 60 kHz, 40 kHz, and 20 kHz, respectively. Our findings suggest that different mechanisms contribute to skin permeability enhancement within each skin region. We propose that the enhancement mechanism within LTRs is the frequency-dependent process of cavitation-induced microjet collapse at the skin surface, while the increased rpore values in non-LTRs are likely due to SLS perturbation, with enhanced penetration of SLS into the skin resulting from the frequency-independent process of microstreaming. PMID:20740667

Characterization of innate lymphoid cells in human skin and blood demonstrates increase of NKp44+ ILC3 in psoriasis.

PubMed

Villanova, Federica; Flutter, Barry; Tosi, Isabella; Grys, Katarzyna; Sreeneebus, Hemawtee; Perera, Gayathri K; Chapman, Anna; Smith, Catherine H; Di Meglio, Paola; Nestle, Frank O

2014-04-01

Innate lymphoid cells (ILCs) are increasingly appreciated as key regulators of tissue immunity. However, their role in human tissue homeostasis and disease remains to be fully elucidated. Here we characterize the ILCs in human skin from healthy individuals and from the inflammatory skin disease psoriasis. We show that a substantial proportion of IL-17A and IL-22 producing cells in the skin and blood of normal individuals and psoriasis patients are CD3-negative innate lymphocytes. Deep immunophenotyping of human ILC subsets showed a statistically significant increase in the frequency of circulating NKp44+ ILC3 in the blood of psoriasis patients compared with healthy individuals or atopic dermatitis patients. More than 50% of circulating NKp44+ ILC3 expressed cutaneous lymphocyte-associated antigen, indicating their potential for skin homing. Analysis of skin tissue revealed a significantly increased frequency of total ILCs in the skin compared with blood. Moreover, the frequency of NKp44+ ILC3 was significantly increased in non-lesional psoriatic skin compared with normal skin. A detailed time course of a psoriasis patient treated with anti-tumor necrosis factor showed a close association between therapeutic response, decrease in inflammatory skin lesions, and decrease of circulating NKp44+ ILC3. Overall, data from this initial observational study suggest a potential role for NKp44+ ILC3 in psoriasis pathogenesis.

Characterization of innate lymphoid cells (ILC) in human skin and blood demonstrates increase of NKp44+ ILC3 in psoriasis

PubMed Central

Tosi, Isabella; Grys, Katarzyna; Sreeneebus, Hemawtee; Perera, Gayathri K; Chapman, Anna; Smith, Catherine H; Di Meglio, Paola; Nestle, Frank O

2013-01-01

Innate lymphoid cells (ILC) are increasingly appreciated as key regulators of tissue immunity. However, their role in human tissue homeostasis and disease remains to be fully elucidated. Here we characterise the ILC in human skin from healthy individuals and from the inflammatory skin disease psoriasis. We show that a substantial proportion of IL-17A and IL-22 producing cells in skin and blood of normal individuals and psoriasis patients are CD3 negative innate lymphocytes. Deep immunophenotyping of human ILC subsets showed a statistically significant increase in the frequency of circulating NKp44+ ILC3 in blood of psoriasis patients compared to healthy individuals or atopic dermatitis patients. More than 50% of circulating NKp44+ ILC3 expressed cutaneous lymphocyte-associated antigen indicating their potential for skin homing. Analysis of skin tissue revealed a significantly increased frequency of total ILC in skin compared to blood. Moreover the frequency of NKp44+ ILC3 was significantly increased in non-lesional psoriatic skin compared to normal skin. A detailed time course of a psoriasis patient treated with anti-TNF showed a close association between therapeutic response, decrease in inflammatory skin lesions, and decrease of circulating NKp44+ ILC3. Overall, data from this initial observational study suggest a potential role for NKp44+ ILC3 in psoriasis pathogenesis. PMID:24352038

Measurements of temperature characteristics and estimation of terahertz negative differential conductance in resonant-tunneling-diode oscillators

NASA Astrophysics Data System (ADS)

Asada, M.; Suzuki, S.; Fukuma, T.

2017-11-01

The temperature dependences of output power, oscillation frequency, and current-voltage curve are measured for resonant-tunneling-diode terahertz (THz) oscillators. The output power largely changes with temperature owing to the change in Ohmic loss. In contrast to the output power, the oscillation frequency and current-voltage curve are almost insensitive to temperature. The measured temperature dependence of output power is compared with the theoretical calculation including the negative differential conductance (NDC) as a fitting parameter assumed to be independent of temperature. Very good agreement was obtained between the measurement and calculation, and the NDC in the THz frequency region is estimated. The results show that the absolute values of NDC in the THz region significantly decrease relative to that at DC, and increases with increasing frequency in the measured frequency range.

Frequency dependence of fatigue life and internal heating of a fiber-reinforced/ceramic-matrix composite

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

Holmes, J.W.; Wu, X.; Sorensen, B.F.

The influence of loading frequency on the fatigue life and internal (frictional) heating of unidirectional SiC-fiber/calcium aluminosilicate-matrix composites was investigated at room temperature. Specimens were subjected to tension-tension fatigue at sinusoidal loading frequencies from 25 to 350 Hz and maximum fatigue stresses of 180 to 240 MPa. The key findings of the study were that (1) fatigue life decreased sharply as the loading frequency was increased, (2) for all loading frequencies, fatigue failures occurred at stress levels that were significantly below the monotonic proportional limit stress if [approximately]285 MPa, and (3) pronounced internal heating occurred during fatigue, with the surfacemore » temperature of the fatigue specimens increasing by 160 K during 350-Hz fatigue at a peak stress of 240 MPa.« less

Low frequency dove coos vary across noise gradients in an urbanized environment.

PubMed

Guo, Fengyi; Bonebrake, Timothy C; Dingle, Caroline

2016-08-01

Urbanization poses a challenge to bird communication due to signal masking by ambient noise and reflective surfaces that lead to signal degradation. Bird species (especially oscines) have been shown to alter their singing behaviour to increase signal efficiency in highly urbanized environments. However, few studies on the effects of noise on song structure have included birds with low frequency vocal signals which may be especially vulnerable to noise pollution due to significant frequency overlap of their signals with traffic noise. We compared the perch coos of spotted doves (Streptopelia chinensis), a species with very low frequency vocalizations, in different background noise levels across urban and peri-urban areas in Hong Kong. We documented a 10% upward shift in the minimum frequency of coos of spotted doves across the noise gradient (a relatively small but significant shift), and a reduced maximum frequency in urban habitats with a higher density of built up area. Hong Kong doves had significantly higher minimum and maximum frequencies than doves from throughout their range (from mostly rural sites). Our results indicate that urban species with extremely low sound frequencies such as doves can alter their vocalizations in response to variable urban acoustic environments. Copyright © 2016 Elsevier B.V. All rights reserved.

Important influence of respiration on human R-R interval power spectra is largely ignored

NASA Technical Reports Server (NTRS)

Brown, T. E.; Beightol, L. A.; Koh, J.; Eckberg, D. L.

1993-01-01

Frequency-domain analyses of R-R intervals are used widely to estimate levels of autonomic neural traffic to the human heart. Because respiration modulates autonomic activity, we determined for nine healthy subjects the influence of breathing frequency and tidal volume on R-R interval power spectra (fast-Fourier transform method). We also surveyed published literature to determine current practices in this burgeoning field of scientific inquiry. Supine subjects breathed at rates of 6, 7.5, 10, 15, 17.1, 20, and 24 breaths/min and with nominal tidal volumes of 1,000 and 1,500 ml. R-R interval power at respiratory and low (0.06-0.14 Hz) frequencies declined significantly as breathing frequency increased. R-R interval power at respiratory frequencies was significantly greater at a tidal volume of 1,500 than 1,000 ml. Neither breathing frequency nor tidal volume influenced average R-R intervals significantly. Our review of studies reporting human R-R interval power spectra showed that 51% of the studies controlled respiratory rate, 11% controlled tidal volume, and 11% controlled both respiratory rate and tidal volume. The major implications of our analyses are that breathing parameters strongly influence low-frequency as well as respiratory frequency R-R interval power spectra and that this influence is largely ignored in published research.

Doubling of coastal flooding frequency within decades due to sea-level rise

USGS Publications Warehouse

Vitousek, Sean; Barnard, Patrick L.; Fletcher, Charles H.; Frazer, Neil; Erikson, Li; Storlazzi, Curt D.

2017-01-01

Global climate change drives sea-level rise, increasing the frequency of coastal flooding. In most coastal regions, the amount of sea-level rise occurring over years to decades is significantly smaller than normal ocean-level fluctuations caused by tides, waves, and storm surge. However, even gradual sea-level rise can rapidly increase the frequency and severity of coastal flooding. So far, global-scale estimates of increased coastal flooding due to sea-level rise have not considered elevated water levels due to waves, and thus underestimate the potential impact. Here we use extreme value theory to combine sea-level projections with wave, tide, and storm surge models to estimate increases in coastal flooding on a continuous global scale. We find that regions with limited water-level variability, i.e., short-tailed flood-level distributions, located mainly in the Tropics, will experience the largest increases in flooding frequency. The 10 to 20 cm of sea-level rise expected no later than 2050 will more than double the frequency of extreme water-level events in the Tropics, impairing the developing economies of equatorial coastal cities and the habitability of low-lying Pacific island nations.

[Inheritance of bc1 gene in intersubspecific hybrids of rice (Oryza sativa L.)].

PubMed

Lü, Chuan-Gen; Zong, Shou-Yu; Zhao, Ling; Qi, Qing-Ming; Zou, Jiang-Shi; Ikehashi, Hiroshi

2004-10-01

Distorted segregation of the brittle culm-1 gene (bc1) on rice chromosome 3 was found with greatly increased or decreased frequency of bc1 bc1 genotype in inter-subspecific hybrids, although the gene normally transmitted to its offspring following the Mendelian Law in intra-subspecific hybrids. In a combination of Kamairazu//Ketan Nangka/Kamairazu,an increased frequency of bc1 bc1 in F1, normal segregation in F2, and increased and decreased frequency in a few F3 and F4 lines were observed. In a cross of IR36/Kamairazu, decreased frequency in F2, both normal and decreased segregations in F3 and F4, and a few lines of increased ratio in F4 were found. In F2 of Ketan Nangka/IR36//Kamairazu, increased and decreased and normal segregations were all observed. There was no significant correlation between the frequency of bc1 bc1 and pollen fertility. It implied that distorted segregation of bc1 was caused by selective fertilization of male gametes, which were governed by gametophyte genes of ga2, ga3 and ga14 on chromosome 3.

Increased skills usage statistically mediates symptom reduction in self-guided internet-delivered cognitive-behavioural therapy for depression and anxiety: a randomised controlled trial.

PubMed

Terides, Matthew D; Dear, Blake F; Fogliati, Vincent J; Gandy, Milena; Karin, Eyal; Jones, Michael P; Titov, Nickolai

2018-01-01

Cognitive-behavioural therapy (CBT) is an effective treatment for clinical and subclinical symptoms of depression and general anxiety, and increases life satisfaction. Patients' usage of CBT skills is a core aspect of treatment but there is insufficient empirical evidence suggesting that skills usage behaviours are a mechanism of clinical change. This study investigated if an internet-delivered CBT (iCBT) intervention increased the frequency of CBT skills usage behaviours and if this statistically mediated reductions in symptoms and increased life satisfaction. A two-group randomised controlled trial was conducted comparing internet-delivered CBT (n = 65) with a waitlist control group (n = 75). Participants were individuals experiencing clinically significant symptoms of depression or general anxiety. Mixed-linear models analyses revealed that the treatment group reported a significantly higher frequency of skills usage, lower symptoms, and higher life satisfaction by the end of treatment compared with the control group. Results from bootstrapping mediation analyses revealed that the increased skills usage behaviours statistically mediated symptom reductions and increased life satisfaction. Although skills usage and symptom outcomes were assessed concurrently, these findings support the notion that iCBT increases the frequency of skills usage behaviours and suggest that this may be an important mechanism of change.

Altered GABAA receptor-mediated synaptic transmission disrupts the firing of gonadotropin-releasing hormone neurons in male mice under conditions that mimic steroid abuse

PubMed Central

Penatti, Carlos A A; Davis, Matthew C; Porter, Donna M; Henderson, Leslie P

2010-01-01

Gonadotropin–releasing hormone (GnRH) neurons are the central regulators of reproduction. GABAergic transmission plays a critical role in pubertal activation of pulsatile GnRH secretion. Self-administration of excessive doses of anabolic androgenic steroids (AAS) disrupts reproductive function and may have critical repercussions for pubertal onset in adolescent users. Here, we demonstrate that chronic treatment of adolescent male mice with the AAS, 17α-methyltestosterone (17αMT), significantly decreased action potential frequency in GnRH neurons, reduced the serum gonadotropin levels, and decreased testes mass. AAS treatment did not induce significant changes in GABAA receptor subunit mRNA levels or alter the amplitude or decay kinetics of GABAA receptor-mediated spontaneous postsynaptic currents (sPSC) or tonic currents in GnRH neurons. However, AAS treatment significantly increased action potential frequency in neighboring medial preoptic area (mPOA) neurons and GABAA receptor-mediated sPSC frequency in GnRH neurons. In addition, physical isolation of the more lateral aspects of the mPOA from the medially-localized GnRH neurons abrogated the AAS-induced increase in GABAA receptor-mediated sPSC frequency and the decrease in action potential firing in the GnRH cells. Our results indicate that AAS act predominantly on steroid-sensitive presynaptic neurons within the mPOA to impart significant increases in GABAA receptor-mediated inhibitory tone onto downstream GnRH neurons resulting in diminished activity of these pivotal mediators of reproductive function. These AAS-induced changes in central GABAergic circuits of the forebrain may significantly contribute to the disruptive actions of these drugs on pubertal maturation and the development of reproductive competence in male steroid abusers. PMID:20463213

Treatment satisfaction in type 2 diabetes patients taking empagliflozin compared with patients taking glimepiride.

PubMed

Chirila, Costel; Zheng, Qingyao; Davenport, Eric; Kaschinski, Dagmar; Pfarr, Egon; Hach, Thomas; Palencia, Roberto

2016-05-01

This exploratory analysis assessed and compared patients' treatment satisfaction with empagliflozin plus metformin versus glimepiride plus metformin, using data obtained from the Diabetes Treatment Satisfaction Questionnaire, status version (DTSQs) collected in a randomized, double-blind, double-dummy clinical trial. Observed values for DTSQs scale score and each of its eight items were summarized by visit and treatment arm. Changes from baseline in these scores were analyzed using linear mixed models for repeated measures. The baseline scale score and item scores were comparable between empagliflozin plus metformin (n = 765) and glimepiride plus metformin (n = 780). Compared with baseline, patients reported significant treatment satisfaction increases and significant decreases in perceived hyperglycemia with both treatments at all visits. Also, compared with baseline, a significant increase in perceived frequency of hypoglycemia was observed in the glimepiride treatment group at all visits. No statistically significant treatment difference was observed in DTSQs scale score and its items at week 104. The difference between the treatment groups was significant and in favor of empagliflozin from week 28 onward for perceived frequency of hyperglycemia (P ≤ 0.006) and perceived frequency of hypoglycemia (P ≤ 0.011). Despite positive trends in favor of empagliflozin, there was no significant difference in DTSQs scale score between empagliflozin and glimepiride at 104 weeks. However, when compared with glimepiride, empagliflozin demonstrated significantly lower perceived frequency of hyperglycemia and hypoglycemia at all visits from week 28 onward. This finding is consistent with the clinical results reported for the EMPA-REG H2H-SU trial.

Effects of milking frequency in automatic milking systems on salivary cortisol, immunoglobulin A, somatic cell count and melatonin.

PubMed

Helmreich, S; Wechsler, B; Hauser, R; Gygax, L

2016-03-01

In barns with an automatic milking system (AMS), both the milking frequency and the number of nighttime milkings vary between cows. A low milking frequency might indicate problems in gaining access to the milking unit. Also, nighttime lighting in the waiting area of the AMS and in the milking unit increases exposure to light at night and could suppress nocturnal melatonin synthesis. These effects could result in increased stress, suppressed immune response, and poor udder health. A total of 125 cows (14-16/farm) on 8 farms with AMS were selected based on their average milking frequency. Eight to 10 saliva samples per cow were taken over the course of 4 days, and cortisol, IgA and melatonin concentrations were determined. Somatic cell counts (SCC) were determined in milk samples. Milking frequency had no significant relationship with mean cortisol and IgA levels, but a higher milking frequency tended to be associated with lower SCC levels. Nocturnal melatonin levels tended to be negatively associated with the number of nighttime milkings. In conclusion, no indication of increased stress or reduced immune defense was found in relation to milking frequency on farms with an AMS.

Radiation induction of drug resistance in RIF-1 tumors and tumor cells

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

Hopwood, L.E.; Moulder, J.E.

1989-11-01

The RIF-1 tumor cell line contains a small number of cells (1-20 per 10(6) cells) that are resistant to various single antineoplastic drugs, including 5-fluorouracil (5FU), methotrexate (MTX), and adriamycin (ADR). For 5FU the frequency of drug resistance is lower for tumor-derived cells than for cells from cell culture; for MTX the reverse is true, and for ADR there is no difference. In vitro irradiation at 5 Gy significantly increased the frequency of drug-resistant cells for 5FU, MTX, and ADR. In vivo irradiation at 3 Gy significantly increased the frequency of drug-resistant cells for 5FU and MTX, but not formore » ADR. The absolute risk for in vitro induction of MTX, 5FU, and ADR resistance, and for in vivo induction of 5FU resistance, was 1-3 per 10(6) cells per Gy; but the absolute risk for in vivo induction of MTX resistance was 54 per 10(6) cells per Gy. The frequency of drug-resistant cells among individual untreated tumors was highly variable; among individual irradiated tumors the frequency of drug-resistant cells was significantly less variable. These studies provide supporting data for models of the development of tumor drug resistance, and imply that some of the drug resistance seen when chemotherapy follows radiotherapy may be due to radiation-induced drug resistance.« less

Vicia root-mirconucleus and sister chromatid exchange assays on the genotoxicity of selenium compounds.

PubMed

Yi, Huilan; Si, Liangyan

2007-06-15

Selenium (Se) is an important metalloid with industrial, environmental, biological and toxicological significance. Excessive selenium in soil and water may contribute to environmental selenium pollution, and affect plant growth and human health. By using Vicia faba micronucleus (MN) and sister chromatid exchange (SCE) tests, possible genotoxicity of sodium selenite and sodium biselenite was evaluated in this study. The results showed that sodium selenite, at concentrations from 0.01 to 10.0mg/L, induced a 1.9-3.9-fold increase in MN frequency and a 1.5-1.6-fold increase in SCE frequency, with a statistically significantly difference from the control (P<0.05 and 0.01, respectively). Sodium selenite also caused mitotic delay and a 15-80% decrease in mitotic indices (MI), but at the lowest concentration (0.005mg/L), it slightly stimulated mitotic activity. Similarly, the frequencies of MN and SCE also increased significantly in sodium biselenite treated samples, with MI decline only at relatively higher effective concentrations. Results of the present study suggest that selenite is genotoxic to V. faba root cells and may be a genotoxic risk to human health.

Reflex effects on components of synchronized renal sympathetic nerve activity.

PubMed

DiBona, G F; Jones, S Y

1998-09-01

The effects of peripheral thermal receptor stimulation (tail in hot water, n = 8, anesthetized) and cardiac baroreceptor stimulation (volume loading, n = 8, conscious) on components of synchronized renal sympathetic nerve activity (RSNA) were examined in rats. The peak height and peak frequency of synchronized RSNA were determined. The renal sympathoexcitatory response to peripheral thermal receptor stimulation was associated with an increase in the peak height. The renal sympathoinhibitory response to cardiac baroreceptor stimulation was associated with a decrease in the peak height. Although heart rate was significantly increased with peripheral thermal receptor stimulation and significantly decreased with cardiac baroreceptor stimulation, peak frequency was unchanged. As peak height reflects the number of active fibers, reflex increases and decreases in synchronized RSNA are mediated by parallel increases and decreases in the number of active renal nerve fibers rather than changes in the centrally based rhythm or peak frequency. The increase in the number of active renal nerve fibers produced by peripheral thermal receptor stimulation reflects the engagement of a unique group of silent renal sympathetic nerve fibers with a characteristic response pattern to stimulation of arterial baroreceptors, peripheral and central chemoreceptors, and peripheral thermal receptors.

Child physical and sexual abuse and cigarette smoking in adolescence and adulthood.

PubMed

Kristman-Valente, Allison N; Brown, Eric C; Herrenkohl, Todd I

2013-10-01

Analyses used data from an extended longitudinal study to examine the relationship between childhood physical and sexual abuse (CPA and CSA, respectively) and adolescent and adult smoking behavior. Two questions guided the study: (1) Is there an association between childhood abuse and adolescent and adult smoking behavior? (2) Does the relationship between childhood abuse and later cigarette smoking differ for males and females? A censored-inflated path model was used to assess the impact of child abuse on adolescent and adult lifetime smoking prevalence and smoking frequency. Gender differences in significant model paths were assessed using a multiple-group approach. Results show no significant relation between CPA or CSA and risk of having ever smoked cigarettes in adolescence or adulthood. However, for males, both CPA and CSA had direct effects on adolescent smoking frequency. For females, only CSA predicted increased smoking frequency in adolescence. Adolescent smoking frequency predicted adult smoking frequency more strongly for females compared with males. CPA and CSA are risk factors for higher frequency of smoking in adolescence. Higher frequency of cigarette smoking in adolescence increases the risk of higher smoking frequency in adulthood. Results underscore the need for both primary and secondary prevention and intervention efforts to reduce the likelihood of childhood abuse and to lessen risk for cigarette smoking among those who have been abused. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

FG7142, yohimbine, and βCCE produce anxiogenic-like effects in the elevated plus-maze but do not affect brainstem activated hippocampal theta.

PubMed

Yeung, Michelle; Lu, Lily; Hughes, Adam M; Treit, Dallas; Dickson, Clayton T

2013-12-01

The neurobiological underpinnings of anxiety are of paramount importance to selective and efficacious pharmaceutical intervention. Hippocampal theta frequency in urethane anaesthetized rats is suppressed by all known (and some previously unknown) anti-anxiety (anxiolytic) drugs. Although these findings support the predictive validity of this assay, its construct validity (i.e., whether theta frequency actually indexes anxiety per se) has not been a subject of systematic investigation. We reasoned that if anxiolytic drugs suppress hippocampal theta frequency, then drugs that increase anxiety (i.e., anxiogenic agents) should increase theta frequency, thus providing evidence of construct validity. We used three proven anxiogenic drugs--two benzodiazepine receptor inverse agonists, N-methyl-β-carboline-3-carboxamide (FG7142) and β-carboline-3-carboxylate ethyl ester (βCCE), and one α2 noradrenergic receptor antagonist, 17α-hydroxy-yohimban-16α-carboxylic acid methyl ester (yohimbine) as pharmacological probes to assess the construct validity of the theta model. Although all three anxiogenic drugs significantly increased behavioural measures of anxiety in the elevated plus-maze, none of the three increased the frequency of hippocampal theta oscillations in the neurophysiological model. As a positive control, we demonstrated that diazepam, a proven anxiolytic drug, decreased the frequency of hippocampal theta, as in all other studies using this model. Given this discrepancy between the significant effects of anxiogenic drugs in the behavioural model and the null effects of these drugs in the neurophysiological model, we conclude that the construct validity of the hippocampal theta model of anxiety is questionable. Copyright © 2013 Elsevier Ltd. All rights reserved.

The effect of 30 Hz vs. 50 Hz passive vibration and duration of vibration on skin blood flow in the arm.

PubMed

Maloney-Hinds, Colleen; Petrofsky, Jerrold Scott; Zimmerman, Grenith

2008-03-01

Recently, researchers have demonstrated that Whole Body Vibration (WBV) results in significant increases in skin blood flow (SBF). No study has determined if a specific frequency or a specific duration is better at optimizing SBF. Two studies were conducted to determine, 1) if there is a difference in SBF due to passive vibration of the forearm at 30 Hz vs. 50 Hz, 2) if one frequency is superior, and 3) if there is an optimal duration. In the first study, 18 subjects (mean age 20.3+/-2.9 years) were randomly placed into a 30 Hz or 50 Hz vibration group, and in the second, seven subjects (mean age 23.3+/-3.8 years) participated in both 30 and 50 Hz vibration. Each subject's arm was passively vibrated for 10 minutes. SBF was examined during vibration and for 15 minutes of recovery. Both frequencies produced significant increases in SBF (p<0.05) within the first four minutes of vibration. Peak SBFs were obtained by the fifth minute. SBF remained high for minutes 4 through 10 of vibration in the second study. In the first study, SBF remained high for minutes 4 through 9. During recovery, 30 Hz vibration produced SBFs below baseline values while 50 Hz SBFs remained above baseline. Statistically one frequency was not superior to the other. Five minutes of 30 Hz or 50 Hz vibration produced significant increases in SBF. Clinically, 50 Hz has additional benefits because SBF increased more rapidly and did not result in vasoconstriction during the recovery period. Future studies should be done to determine if these increases in SBF could be of benefit to populations with low circulation such as those with diabetes.

Effects of different frequencies of repetitive transcranial magnetic stimulation on the recovery of upper limb motor dysfunction in patients with subacute cerebral infarction.

PubMed

Li, Jiang; Meng, Xiang-Min; Li, Ru-Yi; Zhang, Ru; Zhang, Zheng; Du, Yi-Feng

2016-10-01

Studies have confirmed that low-frequency repetitive transcranial magnetic stimulation can decrease the activity of cortical neurons, and high-frequency repetitive transcranial magnetic stimulation can increase the excitability of cortical neurons. However, there are few studies concerning the use of different frequencies of repetitive transcranial magnetic stimulation on the recovery of upper-limb motor function after cerebral infarction. We hypothesized that different frequencies of repetitive transcranial magnetic stimulation in patients with cerebral infarction would produce different effects on the recovery of upper-limb motor function. This study enrolled 127 patients with upper-limb dysfunction during the subacute phase of cerebral infarction. These patients were randomly assigned to three groups. The low-frequency group comprised 42 patients who were treated with 1 Hz repetitive transcranial magnetic stimulation on the contralateral hemisphere primary motor cortex (M1). The high-frequency group comprised 43 patients who were treated with 10 Hz repetitive transcranial magnetic stimulation on ipsilateral M1. Finally, the sham group comprised 42 patients who were treated with 10 Hz of false stimulation on ipsilateral M1. A total of 135 seconds of stimulation was applied in the sham group and high-frequency group. At 2 weeks after treatment, cortical latency of motor-evoked potentials and central motor conduction time were significantly lower compared with before treatment. Moreover, motor function scores were significantly improved. The above indices for the low- and high-frequency groups were significantly different compared with the sham group. However, there was no significant difference between the low- and high-frequency groups. The results show that low- and high-frequency repetitive transcranial magnetic stimulation can similarly improve upper-limb motor function in patients with cerebral infarction.

Electrogastrography in experimental pigs: the influence of gastrointestinal injury induced by dextran sodium sulphate on porcine gastric erythromycin-stimulated myoelectric activity.

PubMed

Tachecí, Ilja; Kvetina, Jaroslav; Kunes, Martin; Edakkanambeth Varayil, Jithinraj; Ali, Shahzad Marghoob; Pavlik, Michal; Kopacova, Marcela; Rejchrt, Stanislav; Bures, Jan; Pleskot, Miloslav

2011-01-01

Electrogastrography (EGG) is a non-invasive investigation of gastric myoelectrical activity. The aim of study was to evaluate the impact of erythromycin on EGG in gastrointestinal toxic injury induced by dextran sodium sulphate (DSS) in experimental pigs. The experiments were carried out on 12 adult pigs (weighing 30-35 kg). EGG was recorded using Digitrapper equipment (Synectics Medical AB, Stockholm). Running spectrum activity was used for EGG evaluation. There were two groups of animals: Group I: 6 controls with erythromycin administration (1,600 mg intragastrically); Group II: 6 animals treated with DSS (for 5 days, 0.25 g/kg per day in a dietary bolus) followed by erythromycin administration. Baseline and subsequent six separate 30-minute EGG-recordings (from time 0 to 360 min) were accomplished in each animal. A total of 84 records were analysed. Baseline dominant frequency of slow waves was fully comparable in both groups. In Group I, there was a significant increase in dominant frequency after erythromycin administration (maximum between 240-360 min). There was a flat non-significant and delayed increase in dominant frequency after erythromycin administration in Group II. The difference between Group I and II at particular time intervals was not significant but a diverse trend was evident. EGG recording enables us to register a gastric myoelectrical effect of prokinetic drugs. Erythromycin induced a significant increase in the dominant frequency of slow waves. DSS caused toxic injury to the porcine gastrointestinal tract responsible for the delayed and weaker myoelectrical effect of erythromycin in experimental animals.

Vocal warm-up increases phonation threshold pressure in soprano singers at high pitch.

PubMed

Motel, Tamara; Fisher, Kimberly V; Leydon, Ciara

2003-06-01

Vocal warm-up is thought to optimize singing performance. We compared effects of short-term, submaximal, vocal warm-up exercise with those of vocal rest on the soprano voice (n = 10, ages 19-21 years). Dependent variables were the minimum subglottic air pressure required for vocal fold oscillation to occur (phonation threshold pressure, Pth), and the maximum and minimum phonation fundamental frequency. Warm-up increased Pth for high pitch phonation (p = 0.033), but not for comfortable (p = 0.297) or low (p = 0.087) pitch phonation. No significant difference in the maximum phonation frequency (p = 0.193) or minimum frequency (p = 0.222) was observed. An elevated Pth at controlled high pitch, but an unchanging maximum and minimum frequency production suggests that short-term vocal exercise may increase the viscosity of the vocal fold and thus serve to stabilize the high voice.

Effects of Proof Mass Geometry on Piezoelectric Vibration Energy Harvesters

PubMed Central

Gratuze, Mathieu; Elsayed, Mohannad Y.

2018-01-01

Piezoelectric energy harvesters have proven to have the potential to be a power source in a wide range of applications. As the harvester dimensions scale down, the resonance frequencies of these devices increase drastically. Proof masses are essential in micro-scale devices in order to decrease the resonance frequency and increase the strain along the beam to increase the output power. In this work, the effects of proof mass geometry on piezoelectric energy harvesters are studied. Different geometrical dimension ratios have significant impact on the resonance frequency, e.g., beam to mass lengths, and beam to mass widths. A piezoelectric energy harvester has been fabricated and tested operating at a frequency of about 4 kHz within the audible range. The responses of various prototypes were studied, and an optimized T-shaped piezoelectric vibration energy harvester design is presented for improved performance. PMID:29772706

Effects of Proof Mass Geometry on Piezoelectric Vibration Energy Harvesters.

PubMed

Alameh, Abdul Hafiz; Gratuze, Mathieu; Elsayed, Mohannad Y; Nabki, Frederic

2018-05-16

Piezoelectric energy harvesters have proven to have the potential to be a power source in a wide range of applications. As the harvester dimensions scale down, the resonance frequencies of these devices increase drastically. Proof masses are essential in micro-scale devices in order to decrease the resonance frequency and increase the strain along the beam to increase the output power. In this work, the effects of proof mass geometry on piezoelectric energy harvesters are studied. Different geometrical dimension ratios have significant impact on the resonance frequency, e.g., beam to mass lengths, and beam to mass widths. A piezoelectric energy harvester has been fabricated and tested operating at a frequency of about 4 kHz within the audible range. The responses of various prototypes were studied, and an optimized T-shaped piezoelectric vibration energy harvester design is presented for improved performance.

Climate change is projected to have severe impacts on the frequency and intensity of peak electricity demand across the United States.

PubMed

Auffhammer, Maximilian; Baylis, Patrick; Hausman, Catherine H

2017-02-21

It has been suggested that climate change impacts on the electric sector will account for the majority of global economic damages by the end of the current century and beyond [Rose S, et al. (2014) Understanding the Social Cost of Carbon: A Technical Assessment ]. The empirical literature has shown significant increases in climate-driven impacts on overall consumption, yet has not focused on the cost implications of the increased intensity and frequency of extreme events driving peak demand, which is the highest load observed in a period. We use comprehensive, high-frequency data at the level of load balancing authorities to parameterize the relationship between average or peak electricity demand and temperature for a major economy. Using statistical models, we analyze multiyear data from 166 load balancing authorities in the United States. We couple the estimated temperature response functions for total daily consumption and daily peak load with 18 downscaled global climate models (GCMs) to simulate climate change-driven impacts on both outcomes. We show moderate and heterogeneous changes in consumption, with an average increase of 2.8% by end of century. The results of our peak load simulations, however, suggest significant increases in the intensity and frequency of peak events throughout the United States, assuming today's technology and electricity market fundamentals. As the electricity grid is built to endure maximum load, our findings have significant implications for the construction of costly peak generating capacity, suggesting additional peak capacity costs of up to 180 billion dollars by the end of the century under business-as-usual.

CK-2127107 amplifies skeletal muscle response to nerve activation in humans.

PubMed

Andrews, Jinsy A; Miller, Timothy M; Vijayakumar, Vipin; Stoltz, Randall; James, Joyce K; Meng, Lisa; Wolff, Andrew A; Malik, Fady I

2018-05-01

Three studies evaluated safety, tolerability, pharmacokinetics, and pharmacodynamics of CK-2127107 (CK-107), a next-generation fast skeletal muscle troponin activator (FSTA), in healthy participants. We tested the hypothesis that CK-107 would amplify the force-frequency response of muscle in humans. To assess the force-frequency response, participants received single doses of CK-107 and placebo in a randomized, double-blind, 4-period, crossover study. The force-frequency response of foot dorsiflexion following stimulation of the deep fibular nerve to activate the tibialis anterior muscle was assessed. CK-107 significantly increased tibialis anterior muscle response with increasing dose and plasma concentration in a frequency-dependent manner; the largest increase in peak force was ∼60% at 10 Hz. CK-107 appears more potent and produced larger increases in force than tirasemtiv-a first-generation FSTA-in a similar pharmacodynamic study, thereby supporting its development for improvement of muscle function of patients. Muscle Nerve 57: 729-734, 2018. © 2017 The Authors. Muscle & Nerve published by Wiley Periodicals, Inc.

Responses of Middle-Frequency Modulations in Vocal Fundamental Frequency to Different Vocal Intensities and Auditory Feedback.

PubMed

Lee, Shao-Hsuan; Fang, Tuan-Jen; Yu, Jen-Fang; Lee, Guo-She

2017-09-01

Auditory feedback can make reflexive responses on sustained vocalizations. Among them, the middle-frequency power of F0 (MFP) may provide a sensitive index to access the subtle changes in different auditory feedback conditions. Phonatory airflow temperature was obtained from 20 healthy adults at two vocal intensity ranges under four auditory feedback conditions: (1) natural auditory feedback (NO); (2) binaural speech noise masking (SN); (3) bone-conducted feedback of self-generated voice (BAF); and (4) SN and BAF simultaneously. The modulations of F0 in low-frequency (0.2 Hz-3 Hz), middle-frequency (3 Hz-8 Hz), and high-frequency (8 Hz-25 Hz) bands were acquired using power spectral analysis of F0. Acoustic and aerodynamic analyses were used to acquire vocal intensity, maximum phonation time (MPT), phonatory airflow, and MFP-based vocal efficiency (MBVE). SN and high vocal intensity decreased MFP and raised MBVE and MPT significantly. BAF showed no effect on MFP but significantly lowered MBVE. Moreover, BAF significantly increased the perception of voice feedback and the sensation of vocal effort. Altered auditory feedback significantly changed the middle-frequency modulations of F0. MFP and MBVE could well detect these subtle responses of audio-vocal feedback. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Predicting Intracerebral Hemorrhage Growth With the Spot Sign: The Effect of Onset-to-Scan Time.

PubMed

Dowlatshahi, Dar; Brouwers, H Bart; Demchuk, Andrew M; Hill, Michael D; Aviv, Richard I; Ufholz, Lee-Anne; Reaume, Michael; Wintermark, Max; Hemphill, J Claude; Murai, Yasuo; Wang, Yongjun; Zhao, Xingquan; Wang, Yilong; Li, Na; Sorimachi, Takatoshi; Matsumae, Mitsunori; Steiner, Thorsten; Rizos, Timolaos; Greenberg, Steven M; Romero, Javier M; Rosand, Jonathan; Goldstein, Joshua N; Sharma, Mukul

2016-03-01

Hematoma expansion after acute intracerebral hemorrhage is common and is associated with early deterioration and poor clinical outcome. The computed tomographic angiography (CTA) spot sign is a promising predictor of expansion; however, frequency and predictive values are variable across studies, possibly because of differences in onset-to-CTA time. We performed a patient-level meta-analysis to define the relationship between onset-to-CTA time and frequency and predictive ability of the spot sign. We completed a systematic review for studies of CTA spot sign and hematoma expansion. We subsequently pooled patient-level data on the frequency and predictive values for significant hematoma expansion according to 5 predefined categorized onset-to-CTA times. We calculated spot-sign frequency both as raw and frequency-adjusted rates. Among 2051 studies identified, 12 met our inclusion criteria. Baseline hematoma volume, spot-sign status, and time-to-CTA were available for 1176 patients, and 1039 patients had follow-up computed tomographies for hematoma expansion analysis. The overall spot sign frequency was 26%, decreasing from 39% within 2 hours of onset to 13% beyond 8 hours (P<0.001). There was a significant decrease in hematoma expansion in spot-positive patients as onset-to-CTA time increased (P=0.004), with positive predictive values decreasing from 53% to 33%. The frequency of the CTA spot sign is inversely related to intracerebral hemorrhage onset-to-CTA time. Furthermore, the positive predictive value of the spot sign for significant hematoma expansion decreases as time-to-CTA increases. Our results offer more precise risk stratification for patients with acute intracerebral hemorrhage and will help refine clinical prediction rules for intracerebral hemorrhage expansion. © 2016 American Heart Association, Inc.

Effects of lifestyle on micronuclei frequency in human lymphocytes in Japanese hard-metal workers.

PubMed

Huang, Peixin; Huang, Bin; Weng, Huachun; Nakayama, Kunio; Morimoto, Kanehisa

2009-04-01

The risks of cardiovascular disease, cancer, and other major causes of mortality are largely attributable to lifestyle factors such as smoking, alcohol drinking, hours of working and sleeping, physical activity, diet, and stress. Earlier studies have suggested that an unhealthy lifestyle is also associated with increased lymphocyte sensitivity to mutagens, oxidative DNA damage level, and leukocyte DNA damage. In order to explore the genotoxicity of unhealthy lifestyle, we evaluated the effect of overall lifestyle as well as some individual lifestyle factors on micronuclei (MN) frequency in cultured human lymphocytes. The study was conducted among 208 healthy adult (19 to 59 years) male Japanese hard-metal workers. The subjects were divided into groups according to their self-reported good, moderate, and poor lifestyles based on their responses to a questionnaire regarding eight health practices (cigarette smoking, alcohol consumption, sleeping hours, working hours, physical exercise, eating breakfast, balanced nutrition, and mental stress), the presence or absence of each of which was summed to obtain a health practice index (HPI: range 0-8). Peripheral blood was taken and the cytokinesis-block micronuclei (CBMN) assay was performed. Total lifestyle quality as measured by the HPI was strongly negatively associated with MN frequency in cultured human lymphocytes (p<0.01). Nutritional imbalance, lack of regular exercise (<2 times per week), insufficient sleep (< or =6 h per day), and overtime working (> or =9 h per day) each contributed significantly to higher MN frequency (all p<0.05). In the smoker group, a significantly higher MN frequency was only found in heavy smokers (p<0.05). On the other hand, mental stress, eating breakfast, and alcohol drinking had no effect on MN frequency. Taken together, these findings indicate that poor lifestyle habits significantly increase MN frequency in human lymphocytes.

Gender Identification Using High-Frequency Speech Energy: Effects of Increasing the Low-Frequency Limit.

PubMed

Donai, Jeremy J; Halbritter, Rachel M

The purpose of this study was to investigate the ability of normal-hearing listeners to use high-frequency energy for gender identification from naturally produced speech signals. Two experiments were conducted using a repeated-measures design. Experiment 1 investigated the effects of increasing high-pass filter cutoff (i.e., increasing the low-frequency spectral limit) on gender identification from naturally produced vowel segments. Experiment 2 studied the effects of increasing high-pass filter cutoff on gender identification from naturally produced sentences. Confidence ratings for the gender identification task were also obtained for both experiments. Listeners in experiment 1 were capable of extracting talker gender information at levels significantly above chance from vowel segments high-pass filtered up to 8.5 kHz. Listeners in experiment 2 also performed above chance on the gender identification task from sentences high-pass filtered up to 12 kHz. Cumulatively, the results of both experiments provide evidence that normal-hearing listeners can utilize information from the very high-frequency region (above 4 to 5 kHz) of the speech signal for talker gender identification. These findings are at variance with current assumptions regarding the perceptual information regarding talker gender within this frequency region. The current results also corroborate and extend previous studies of the use of high-frequency speech energy for perceptual tasks. These findings have potential implications for the study of information contained within the high-frequency region of the speech spectrum and the role this region may play in navigating the auditory scene, particularly when the low-frequency portion of the spectrum is masked by environmental noise sources or for listeners with substantial hearing loss in the low-frequency region and better hearing sensitivity in the high-frequency region (i.e., reverse slope hearing loss).

Gum chewing improves swallow frequency and latency in Parkinson patients: a preliminary study.

PubMed

South, Angela R; Somers, Stephanie M; Jog, Mandar S

2010-04-13

Reduced swallowing frequency affects secretion management in Parkinson disease (PD). Gum chewing increases saliva flow and swallow frequency. This study uses chewing gum to modify swallow frequency and latency between swallows in patients with PD. 1) Assess the frequency and latency of swallow at baseline (BL), during gum chewing (GC), and post gum chewing (PGC) for participants with PD (stage 2-4) nonsymptomatic for prandial dysphagia; and 2) assess carryover after gum is expectorated. Twenty participants were studied across 3 tasks, each of 5 minutes in duration: BL, GC, and PGC. Respiratory and laryngeal signals were continuously recorded using PowerLab (version 5.5.5; ADI Instruments, Castle Hill, Australia). Frequency and latency of swallow events were calculated. Differences (analysis of variance) are reported for frequency (p < 0.000001) and latency (p < 0.000001). Swallow frequency (mean +/- SD) increased during GC (14.95 +/- 3.02) compared with BL (3.1 +/- 2.85) and PGC (7.0 +/- 2.57). Latency in seconds (mean +/- SD) decreased during GC (24.1 +/- 4.174) and increased with BL (131.8 +/- 59.52) and PGC (mean = 60.74 +/- 25.25). Intertask comparisons (t test) found differences in swallow frequency and latency between tasks: BL vs GC (p < 0.0001, p < 0.0001), BL vs PGC (p < 0.0011, p < 0.0009), and GC vs PGC (p < 0.0001, p < 0.0002), respectively. Post hoc analysis showed carryover to 5.317 minutes. Modifying sensorimotor input by chewing gum alters frequency and latency of swallowing and may be an effective strategy for secretion management in Parkinson disease. This study provides Class III evidence that chewing gum increases swallow frequency and decreases latency of swallowing in an experiment in patients with stage 2 to 4 Parkinson disease who are nonsymptomatic for significant prandial dysphagia.

Central Tendency and Dispersion Measures of the Fundamental Frequencies of Four Vowels as Produced by Two Year-Old and Four-Year Children.

NASA Astrophysics Data System (ADS)

Monroe, Roberta Lynn

The intrinsic fundamental frequency effect among vowels is a vocalic phenomenon of adult speech in which high vowels have higher fundamental frequencies in relation to low vowels. Acoustic investigations of children's speech have shown that variability of the speech signal decreases as children's ages increase. Fundamental frequency measures have been suggested as an indirect metric for the development of laryngeal stability and coordination. Studies of the intrinsic fundamental frequency effect have been conducted among 8- and 9-year old children and in infants. The present study investigated this effect among 2- and 4-year old children. Eight 2-year old and eight 4-year old children produced four vowels, /ae/, /i/, /u/, and /a/, in CVC syllables. Three measures of fundamental frequency were taken. These were mean fundamental frequency, the intra-utterance standard deviation of the fundamental frequency, and the extent to which the cycle-to-cycle pattern of the fundamental frequency was predicted by a linear trend. An analysis of variance was performed to compare the two age groups, the four vowels, and the earlier and later repetitions of the CVC syllables. A significant difference between the two age groups was detected using the intra-utterance standard deviation of the fundamental frequency. Mean fundamental frequencies and linear trend analysis showed that voicing of the preceding consonant determined the statistical significance of the age-group comparisons. Statistically significant differences among the fundamental frequencies of the four vowels were not detected for either age group.

Seismic response of rock slopes: Numerical investigations on the role of internal structure

NASA Astrophysics Data System (ADS)

Arnold, L.; Applegate, K.; Gibson, M.; Wartman, J.; Adams, S.; Maclaughlin, M.; Smith, S.; Keefer, D. K.

2013-12-01

The stability of rock slopes is significantly influenced and often controlled by the internal structure of the slope created by such discontinuities as joints, shear zones, and faults. Under seismic conditions, these discontinuities influence both the resistance of a slope to failure and its response to dynamic loading. The dynamic response, which can be characterized by the slope's natural frequency and amplification of ground motion, governs the loading experienced by the slope in a seismic event and, therefore, influences the slope's stability. In support of the Network for Earthquake Engineering Simulation (NEES) project Seismically-Induced Rock Slope Failure: Mechanisms and Prediction (NEESROCK), we conducted a 2D numerical investigation using the discrete element method (DEM) coupled with simple discrete fracture networks (DFNs). The intact rock mass is simulated with a bonded assembly of discrete particles, commonly referred to as the bonded-particle model (BPM) for rock. Discontinuities in the BPM are formed by the insertion of smooth, unbonded contacts along specified planes. The influence of discontinuity spacing, orientation, and stiffness on slope natural frequency and amplification was investigated with the commercially available Particle Flow Code (PFC2D). Numerical results indicate that increased discontinuity spacing has a non-linear effect in decreasing the amplification and increasing the natural frequency of the slope. As discontinuity dip changes from sub-horizontal to sub-vertical, the slope's level of amplification increases while the natural frequency of the slope decreases. Increased joint stiffness decreases amplification and increases natural frequency. The results reveal that internal structure has a strong influence on rock slope dynamics that can significantly change the system's dynamic response and stability during seismic loading. Financial support for this research was provided by the United States National Science Foundation (NSF) under grant CMMI-1156413.

Low-frequency stimulation of the external globus palladium produces anti-epileptogenic and anti-ictogenic actions in rats

PubMed Central

Cheng, Hui; Kuang, Yi-fang; Liu, Yang; Wang, Yi; Xu, Zheng-hao; Gao, Feng; Zhang, Shi-hong; Ding, Mei-ping; Chen, Zhong

2015-01-01

Aim: To investigate the anti-epileptic effects of deep brain stimulation targeting the external globus palladium (GPe) in rats. Methods: For inducing amygdala kindling and deep brain stimulation, bipolar stainless-steel electrodes were implanted in SD rats into right basolateral amygdala and right GPe, respectively. The effects of deep brain stimulation were evaluated in the amygdala kindling model, maximal electroshock model (MES) and pentylenetetrazole (PTZ) model. Moreover, the background EEGs in the amygdala and GPe were recorded. Results: Low-frequency stimulation (0.1 ms, 1 Hz, 15 min) at the GPe slowed the progression of seizure stages and shortened the after-discharge duration (ADD) during kindling acquisition. Furthermore, low-frequency stimulation significantly decreased the incidence of generalized seizures, suppressed the average stage, and shortened the cumulative ADD and generalized seizure duration in fully kindled rats. In addition, low-frequency stimulation significantly suppressed the average stage of MES-induced seizures and increased the latency to generalized seizures in the PTZ model. High-frequency stimulation (0.1 ms, 130 Hz, 5 min) at the GPe had no anti-epileptic effect and even aggravated epileptogenesis induced by amygdala kindling. EEG analysis showed that low-frequency stimulation at the GPe reversed the increase in delta power, whereas high-frequency stimulation at the GPe had no such effect. Conclusion: Low-frequency stimulation, but not high-frequency stimulation, at the GPe exerts therapeutic effect on temporal lobe epilepsy and tonic-colonic generalized seizures, which may be due to interference with delta rhythms. The results suggest that modulation of GPe activity using low-frequency stimulation or drugs may be a promising epilepsy treatment. PMID:26095038

Losartan corrects abnormal frequency response of renal vasculature in congestive heart failure.

PubMed

DiBona, Gerald F; Sawin, Linda L

2003-11-01

In congestive heart failure, renal blood flow is decreased and renal vascular resistance is increased in a setting of increased activity of both the sympathetic nervous and renin-angiotensin systems. The renal vasoconstrictor response to renal nerve stimulation is enhanced. This is associated with an abnormality in the low-pass filter function of the renal vasculature wherein higher frequencies (> or =0.01 Hz) within renal sympathetic nerve activity are not normally attenuated and are passed into the renal blood flow signal. This study tested the hypothesis that excess angiotensin II action mediates the abnormal frequency response characteristics of the renal vasculature in congestive heart failure. In anesthetized rats, the renal vasoconstrictor response to graded frequency renal nerve stimulation was significantly greater in congestive heart failure than in control rats. Losartan attenuated the renal vasoconstrictor response to a significantly greater degree in congestive heart failure than in control rats. In control rats, the frequency response of the renal vasculature was that of a first order (-20 dB/frequency decade) low-pass filter with a corner frequency (-3 dB, 30% attenuation) of 0.002 Hz and 97% attenuation (-30 dB) at > or =0.1 Hz. In congestive heart failure rats, attenuation did not exceed 45% (-5 dB) over the frequency range of 0.001-0.6 Hz. The frequency response of the renal vasculature was not affected by losartan treatment in control rats but was completely restored to normal by losartan treatment in congestive heart failure rats. The enhanced renal vasoconstrictor response to renal nerve stimulation and the associated abnormality in the frequency response characteristics of the renal vasculature seen in congestive heart failure are mediated by the action of angiotensin II on renal angiotensin II AT1 receptors.

Ionospheric Modification from Under-Dense Heating by High-Power HF Transmitter

DTIC Science & Technology

2011-03-03

Auroral Research Program ( HAARP ) is a HF transmitter, which delivers 0.36 to 3.6 GW effective isotropic radiated powers (F.IRP) for the radiation...dense heating, the EIRP of the HAARP heater can be increased significantly by increasing the heater frequency. With higher heater frequency, the loss...1304 local time) and on 13 April from 0812 to 0844 UTC (0012 to 0044 local time), using the HAARP transmitter facility at Gakona, AK, at full power

Northern Hemisphere extratropical winter cyclones variability over the 20th century derived from ERA-20C reanalysis

NASA Astrophysics Data System (ADS)

Varino, Filipa; Arbogast, Philippe; Joly, Bruno; Riviere, Gwendal; Fandeur, Marie-Laure; Bovy, Henry; Granier, Jean-Baptiste

2018-03-01

The multi-decadal variations of wintertime extra-tropical cyclones during the last century are studied using a vorticity-based tracking algorithm applied to the long-term ERA-20C reanalysis from ECMWF. The variability of moderate-to-deep extra-tropical winter cyclones in ERA-20C show three distinct periods. Two at the beginning and at the end of the century (1900-1935 and 1980-2010) present weak or no significant trends in the Northern Hemisphere as a whole and only some regional trends. The period in between (1935-1980) is marked by a significant increase in Northern Hemisphere moderate-to-deep cyclones frequency. During the latter period, polar regions underwent a significant cooling over the whole troposphere that increased and shifted poleward the mid-latitude meridional temperature gradient and the baroclinicity. This is linked to positive-to-negative shifts of the PDO between 1935 and 1957 and of the AMO between 1957 and 1980 which mainly reinforced the storm-track eddy generation in the North Pacific and North Atlantic regions respectively, as seen from baroclinic conversion from mean to eddy potential energy. As a result, both the North Pacific and North Atlantic extra-tropical storms increase in frequency during the two subperiods (1935-1957 and 1957-1980), together with other storm-track quantities such as the high-frequency eddy kinetic energy. In contrast, the first and third periods are characterized by a warming of the polar temperatures. However, as the stronger warming is confined to the lower troposphere, the baroclinicity do not uniformly increase in the whole troposphere. This may explain why the recent rapid increase in polar temperatures has not affected the behaviour of extratropical cyclones very much. Finally, the large magnitude of the positive trend found in moderate-to-deep cyclone frequency during the second period is still questioned as the period is marked by an important increase in the number of assimilated observations. However, the dynamical link between changes in cyclone frequency, changes in large-scale baroclinicity and ocean decadal variability found in the present study makes us confident on the sign of the detected cyclone trend.

Neurotrophin/receptor expression in urinary bladder of mice with overexpression of NGF in urothelium.

PubMed

Girard, Beatrice M; Malley, Susan E; Vizzard, Margaret A

2011-02-01

Urothelium-specific overexpression of nerve growth factor (NGF) in the urinary bladder of transgenic mice stimulates neuronal sprouting in the urinary bladder, produces increased voiding frequency, and results in increased referred somatic hypersensitivity. Additional NGF-mediated pleiotropic changes might contribute to the increased voiding frequency and pelvic hypersensitivity observed in these transgenic mice, such as modulation of other growth factor/receptor systems. Chronic overexpression of NGF in the urothelium was achieved through the use of a highly urothelium-specific uroplakin II promoter. In the present study, we examined NGF, brain-derived neurotrophic factor (BDNF), and associated receptor [p75(NTR), tyrosine kinase (Trk)A, TrkB] transcript and protein expression in urothelium and detrusor smooth muscle of NGF-overexpressing (OE) and littermate wild-type mice, using real-time quantitative reverse transcription-polymerase chain reaction, ELISAs, and semiquantitation of immunohistochemistry. We focused on these growth factor/receptors given the established roles of NGF/TrkA, NGF/p75(NTR), and BDNF/TrkB systems in bladder function. Increased voiding frequency in NGF-OE mice was confirmed by examining urination patterns. BDNF, TrkA, and TrkB protein expression was significantly (P ≤ 0.01) reduced and p75(NTR) protein expression was significantly (P ≤ 0.01) increased in urinary bladder of NGF-OE mice. The NGF-OE-induced changes in neurotrophic factor/receptor expression in urinary bladder may represent compensatory changes to reduce voiding frequency in the NGF-OE mouse.

Achilles tendon vibration-induced changes in plantar flexor corticospinal excitability.

PubMed

Lapole, Thomas; Temesi, John; Gimenez, Philippe; Arnal, Pierrick J; Millet, Guillaume Y; Petitjean, Michel

2015-02-01

Daily Achilles tendon vibration has been shown to increase muscle force, likely via corticospinal neural adaptations. The aim of the present study was to determine the extent by which corticospinal excitability is influenced during direct Achilles tendon vibration. Motor-evoked potentials (MEPs) were elicited in the soleus (SOL), gastrocnemius medialis (GM) and tibialis anterior (TA) by transcranial magnetic stimulation of the motor cortical area of the leg with and without Achilles tendon vibration at various frequencies (50, 80 and 110 Hz). Contralateral homologues were also investigated. SOL and GM MEP amplitude significantly increased by 226 ± 188 and 66 ± 39%, respectively, during Achilles tendon vibration, without any difference between the tested frequencies. No MEP changes were reported for TA or contralateral homologues. Increased SOL and GM MEP amplitude suggests increased vibration-induced corticospinal excitability independent of vibration frequency.

Standardizing communication from acute care providers to primary care providers on critically ill adults.

PubMed

Ellis, Kerri A; Connolly, Ann; Hosseinnezhad, Alireza; Lilly, Craig M

2015-11-01

To increase the frequency of communication of patient information between acute and primary care providers. A secondary objective was to determine whether higher rates of communication were associated with lower rates of hospital readmission 30 days after discharge. A validated instrument was used for telephone surveys before and after an intervention designed to increase the frequency of communication among acute care and primary care providers. The communication intervention was implemented in 3 adult intensive care units from 2 campuses of an academic medical center. The frequency of communication among acute care and primary care providers, the perceived usefulness of the intervention, and its association with 30-day readmission rates were assessed for 202 adult intensive care episodes before and 100 episodes after a communication intervention. The frequency of documented communication increased significantly (5/202 or 2% before to 72/100 or 72% after the intervention; P < .001) and the communication was considered useful by every participating primary care provider. Rates of rehospitalization at 30 days were lower for the intervention group than the preintervention group, but the difference was not statistically significant (41/202 or 23% vs 16/88 or 18% of discharged patients; P = .45; power 0.112 at P = .05). The frequency of communication episodes that provide value can be increased through standardized processes. The key aspects of this effective intervention were setting the expectation that communication should occur, documenting when communication has occurred, and reviewing that documentation during multiprofessional rounds. ©2015 American Association of Critical-Care Nurses.

Peculiarities of the Third Natural Frequency Vibrations of a Cantilever for the Improvement of Energy Harvesting

PubMed Central

Ostasevicius, Vytautas; Janusas, Giedrius; Milasauskaite, Ieva; Zilys, Mindaugas; Kizauskiene, Laura

2015-01-01

This paper focuses on several aspects extending the dynamical efficiency of a cantilever beam vibrating in the third mode. A few ways of producing this mode stimulation, namely vibro-impact or forced excitation, as well as its application for energy harvesting devices are proposed. The paper presents numerical and experimental analyses of novel structural dynamics effects along with an optimal configuration of the cantilever beam. The peculiarities of a cantilever beam vibrating in the third mode are related to the significant increase of the level of deformations capable of extracting significant additional amounts of energy compared to the conventional harvester vibrating in the first mode. Two types of a piezoelectric vibrating energy harvester (PVEH) prototype are analysed in this paper: the first one without electrode segmentation, while the second is segmented using electrode segmentation at the strain nodes of the third vibration mode to achieve effective operation at the third resonant frequency. The results of this research revealed that the voltage generated by any segment of the segmented PVEH prototype excited at the third resonant frequency demonstrated a 3.4–4.8-fold increase in comparison with the non-segmented prototype. Simultaneously, the efficiency of the energy harvester prototype also increased at lower resonant frequencies from 16% to 90%. The insights presented in the paper may serve for the development and fabrication of advanced piezoelectric energy harvesters which would be able to generate a considerably increased amount of electrical energy independently of the frequency of kinematical excitation. PMID:26029948

Propagation effects on satellite systems at frequencies below 10 GHz, a handbook for satellite systems design, 1st edition

NASA Technical Reports Server (NTRS)

Flock, W. L.

1983-01-01

Satellite communications below about 6 GHz may need to contend with ionospheric effects, including Faraday rotation and ionospheric scintillation, which become increasingly significant with decreasing frequency. Scintillation is most serious in equatorial, auroral, and polar latitudes; even the 4 to 6 GHz frequency range turns out to be subject to scintillation to a significant degree of equatorial latitudes. Faraday rotation, excess range or time delay, phase advance, Doppler frequency fluctuations, and dispersion are proportional to total electron content (TEC) or its variation along the path. Tropospheric refraction and fading affects low angle satellite transmissions as well as terrestrial paths. Attenuation and depolarization due to rain become less important with decreasing frequency but need consideration for frequencies of about 4 GHz and higher. Empirically derived relations are useful for estimating the attenuation expected due to rain for particular percentages of time. Aeronautical, maritime, and land mobile satellite services are subject to fading due to multipath propagation.

Tidal and near-inertial peak variations around the diurnal critical latitude

NASA Astrophysics Data System (ADS)

van Haren, Hans

2005-12-01

Spectra from historic long-term open-ocean moored current meter data between latitudes 0° < |$\\varphi$| < 45° reveal a significant drop in semidiurnal tidal band (D2) energy by ~50% at |$\\varphi$| ~ 25-27°, whilst the peak near the local inertial frequency f is increased by a factor of ~10 up to the level of D2-energy at |$\\varphi$| ~ 28-30°, where f coincides with diurnal frequencies. The increase in f-energy is accompanied by a red-shift of the peak frequency to 0.97 +/- 0.01f, or a poleward spreading of enhanced energy. This contrasts with more common blue-shift. The enhancement may be the result of sub-harmonic instability, as supported by sparse significant bicoherence at half-D2, although i) systematic enhancement of diurnal tidal frequencies, notably M1, was not observed, ii) the latitudes of low D2-energy and high f-energy do not coincide. This may be due to a mix of coupled and independent waves, whilst the poleward trapping of sub-f energy suggests non-traditional effects.

Frequency and temperature dependence of electrical breakdown at 21, 30, and 39 GHz.

PubMed

Braun, H H; Döbert, S; Wilson, I; Wuensch, W

2003-06-06

A TeV-range e(+)e(-) linear collider has emerged as one of the most promising candidates to extend the high energy frontier of experimental elementary particle physics. A high accelerating gradient for such a collider is desirable to limit its overall length. Accelerating gradient is mainly limited by electrical breakdown, and it has been generally assumed that this limit increases with increasing frequency for normal-conducting accelerating structures. Since the choice of frequency has a profound influence on the design of a linear collider, the frequency dependence of breakdown has been measured using six exactly scaled single-cell cavities at 21, 30, and 39 GHz. The influence of temperature on breakdown behavior was also investigated. The maximum obtainable surface fields were found to be in the range of 300 to 400 MV/m for copper, with no significant dependence on either frequency or temperature.

Frequency and Temperature Dependence of Electrical Breakdown at 21, 30, and 39GHz

NASA Astrophysics Data System (ADS)

Braun, H. H.; Döbert, S.; Wilson, I.; Wuensch, W.

2003-06-01

A TeV-range e+e- linear collider has emerged as one of the most promising candidates to extend the high energy frontier of experimental elementary particle physics. A high accelerating gradient for such a collider is desirable to limit its overall length. Accelerating gradient is mainly limited by electrical breakdown, and it has been generally assumed that this limit increases with increasing frequency for normal-conducting accelerating structures. Since the choice of frequency has a profound influence on the design of a linear collider, the frequency dependence of breakdown has been measured using six exactly scaled single-cell cavities at 21, 30, and 39GHz. The influence of temperature on breakdown behavior was also investigated. The maximum obtainable surface fields were found to be in the range of 300 to 400 MV/m for copper, with no significant dependence on either frequency or temperature.

Nonradial oscillation modes of compact stars with a crust

NASA Astrophysics Data System (ADS)

Flores, Cesar Vásquez; Hall, Zack B.; Jaikumar, Prashanth

2017-12-01

Oscillation modes of isolated compact stars can, in principle, be a fingerprint of the equation of state (EoS) of dense matter. We study the non-radial high-frequency l =2 spheroidal modes of neutron stars and strange quark stars, adopting a two-component model (core and crust) for these two types of stars. Using perturbed fluid equations in the relativistic Cowling approximation, we explore the effect of a strangelet or hadronic crust on the oscillation modes of strange stars. The results differ from the case of neutron stars with a crust. In comparison to fluid-only configurations, we find that a solid crust on top of a neutron star increases the p -mode frequency slightly with little effect on the f -mode frequency, whereas for strange stars, a strangelet crust on top of a quark core significantly increases the f -mode frequency with little effect on the p -mode frequency.

The Effect of Cognitive Activity on Sleep Maintenance in a Subsequent Daytime Nap.

PubMed

Arzilli, Cinzia; Cerasuolo, Mariangela; Conte, Francesca; Bittoni, Valentina; Gatteschi, Claudia; Albinni, Benedetta; Giganti, Fiorenza; Ficca, Gianluca

2018-01-25

The aim of this study is to assess the effects of a learning task on the characteristics of a subsequent daytime nap. Thirty-eight subjects were administered a control nap (C) and one preceded by a cognitive training session (TR). Relative to C, TR naps showed significantly increased sleep duration with decreased sleep latency, as well as significantly increased sleep efficiency due to reduced awakening frequency. Meaningful trends were also found toward an increase of Stage 2 sleep proportion and a reduction of Stage 1 sleep, percentage of wake after sleep onset (WASO), and frequency of state transitions. Our results indicate that presleep learning favors sleep propensity and maintenance, offering the possibility to explore planned cognitive training as a low-cost treatment for sleep impairments.

Enhancement of the thermoelectric figure of merit in a ferromagnet-quantum dot-superconductor device due to intradot spin-flip scattering and ac field

NASA Astrophysics Data System (ADS)

Xu, Wei-Ping; Zhang, Yu-Ying; Li, Zhi-Jian; Nie, Yi-Hang

2017-08-01

We investigate the thermoelectric properties of a ferromagnet-quantum dot-superconductor hybrid system with the intradot spin-flip scattering and the external microwave field. The results indicate that the increase of figure of merit in the gap is very slight when the spin-flip scattering strength increases, but outside the gap it significantly increases with enhancing spin-flip scattering strength. The presence of microwave field results in photon-assisted Andreev reflection and induces the satellite peaks in conductance spectrum. The appropriate match of spin-flip scattering strength, microwave field strength and frequency can significantly enhances the figure of merit of thermoelectric conversion of the device, which can be used as a scheme improving thermoelectric efficiency using microwave frequency.

Mechanisms underlying very-low-frequency RR-interval oscillations in humans

NASA Technical Reports Server (NTRS)

Taylor, J. A.; Carr, D. L.; Myers, C. W.; Eckberg, D. L.

1998-01-01

BACKGROUND: Survival of post-myocardial infarction patients is related inversely to their levels of very-low-frequency (0.003 to 0.03 Hz) RR-interval variability. The physiological basis for such oscillations is unclear. In our study, we used blocking drugs to evaluate potential contributions of sympathetic and vagal mechanisms and the renin-angiotensin-aldosterone system to very-low-frequency RR-interval variability in 10 young healthy subjects. METHODS AND RESULTS: We recorded RR intervals and arterial pressures during three separate sessions, with the patient in supine and 40 degree upright tilt positions, during 20-minute frequency (0.25 Hz) and tidal volume-controlled breathing after intravenous injections: saline (control), atenolol (0.2 mg/kg, beta-adrenergic blockade), atropine sulfate (0.04 mg/kg, parasympathetic blockade), atenolol and atropine (complete autonomic blockade), and enalaprilat (0.02 mg/kg, ACE blockade). We integrated fast Fourier transform RR-interval spectral power at very low (0.003 to 0.03 Hz), low (0.05 to 0. 15 Hz), and respiratory (0.2 to 0.3 Hz) frequencies. Beta-adrenergic blockade had no significant effect on very-low- or low-frequency RR-interval power but increased respiratory frequency power 2-fold. ACE blockade had no significant effect on low or respiratory frequency RR-interval power but modestly (approximately 21%) increased very-low-frequency power in the supine (but not upright tilt) position (P<0.05). The most profound effects were exerted by parasympathetic blockade: Atropine, given alone or with atenolol, abolished nearly all RR-interval variability and decreased very-low-frequency variability by 92%. CONCLUSIONS: Although very-low-frequency heart period rhythms are influenced by the renin-angiotensin-aldosterone system, as low and respiratory frequency RR-interval rhythms, they depend primarily on the presence of parasympathetic outflow. Therefore the prognostic value of very-low-frequency heart period oscillations may derive from the fundamental importance of parasympathetic mechanisms in cardiovascular health.

Effect of radar frequency on the detection of shaped (low RCS) targets

NASA Astrophysics Data System (ADS)

Moraitis, D.; Alland, S.

The use of shaping to reduce the radar cross-section (RCS) of aircraft and missiles can result in the RCS varying significantly with radar operating frequency. This RCS sensitivity to frequency should be considered when selecting radar frequency and should be accounted for when evaluating radar performance. A detection range increase for shaped (low RCS) targets of a factor of two or greater can be realized for lower frequency radar (e.g., UHF-Band or L-Band) when compared to higher frequency radar (C-Band or X-Band). For low flying (sea skimming) targets, the RCS variation with frequency for shaped (low RCS) targets neutralizes the advantage that higher radar frequencies realize in multipath propagation resulting in approximately the same detection range across the radar bands from UHF to X-Band.

Characterization of High-Frequency Excitation of a Wake by Simulation

NASA Technical Reports Server (NTRS)

Cain, Alan B.; Rogers, Michael M.; Kibens, Valdis; Mansour, Nagi (Technical Monitor)

2003-01-01

Insights into the effects of high-frequency forcing on free shear layer evolution are gained through analysis of several direct numerical simulations. High-frequency forcing of a fully turbulent plane wake results in only a weak transient effect. On the other hand, significant changes in the developed turbulent state may result when high-frequency forcing is applied to a transitional wake. The impacts of varying the characteristics of the high-frequency forcing are examined, particularly, the streamwise wavenumber band in which forcing is applied and the initial amplitude of the forcing. The high-frequency excitation is found to increase the dissipation rate of turbulent kinetic energy, to reduce the turbulent kinetic energy production rate, and to reduce the turbulent kinetic energy suppression increases with forcing amplitude once a threshold level has been reached. For a given initial forcing energy, the largest reduction in turbulent kinetic energy density was achieved by forcing wavenumbers that are about two to three times the neutral wavenumber determined from linear stability theory.

Threshold Evolution as an Analysis of the Different Pulse Frequencies in Rechargeable Systems for Spinal Cord Stimulation.

PubMed

Abejón, David; Rueda, Pablo; Vallejo, Ricardo

2016-04-01

Pulse frequency (Fc) is one of the most important parameters in neurostimulation, with Pulse Amplitude (Pw) and Amplitude (I). Up to certain Fc, increasing the number of pulses will generate action potentials in neighboring neural structures and may facilitate deeper penetration of the electromagnetic fields. In addition, changes in frequency modify the patient's sensation with stimulation. Fifty patients previously implanted with rechargeable current control spinal cord stimulation. With pulse width fixed at 300 μsec, we stimulated at 26 different Fc values between 40 and 1200 Hz and determine the influence of these changes on different stimulation thresholds: perception threshold (Tp ), therapeutic perception (Tt), and discomfort threshold (Td). Simultaneously, paresthesia coverage of the painful area and patient's sensation and satisfaction related to the quality of stimulation were recorded. Pulse Fc is inversely proportional to stimulation thresholds and this influence is statistically significant (p < 0.05). As Pulse Fc increased from 40 to 1200 Hz, the mean threshold decreases from 7.25 to 1.38 mA (Tp ), 8.17 to 1.63 (Tt ), and 9.20 to 1.85 (Td). Significant differences for Tp and Tt began at 750 Hz (Tp , Tt ) and at 650 Hz for Td. No significant influence was found regarding paresthesia coverage. As expected, Fc affects significantly patient's sensation and satisfaction. Changes in Fc affect the quality of paresthesias. Within the evaluated parameters higher frequencies are inversely proportional to stimulation thresholds and Tt. It seems that Fc is a vital parameter to achieve therapeutic success. Changes in Fc is a useful parameter to modulate the patient's sensory perception. Fc can be successfully used to adjust the quality of the paresthesias and to modify patient's subjective sensation. We showed that as the frequency increases, the patient's satisfaction with the perceived sensation decreases, suggesting that higher Fc may need to be set up at subthreshold amplitude to achieve positive response. © 2016 International Neuromodulation Society.

Influence des conditions climatiques saisonnières sur quelques paramètres physiologiques dès boucs Créoles alimentés avec de l'ensilage de banane

NASA Astrophysics Data System (ADS)

Fauconneau, B.; Xande, A.

1986-06-01

Response of three groups of 12 male creole goats (weighing about 10 kg) to environmental variations was tested in Guadeloupe (French West Indies) respectively at three times in the year: end of humid season (October November), dry season (February March) and beginning of humid season (July August). Voluntary free intake of banana silage (silage of mixed green banana, bagassa, wheat bran and urea complemented with molasse) was not significantly affected by climatic variations. Three physiological parameters: rectal temperature, respiratory frequency and cardiac frequency were measured. These parameters were correlated with heat production dependent factors such as metabolic body weight, body weight gain and voluntary free intake. Rectal temperature increased all through the day until sunset and then decreased during the night. Both minimal rectal temperature and daily increase of rectal temperature were correlated with ambient temperature. Cardiac frequency increased during feeding. Generally cardiac frequency seemed to be correlated with activity of animals and so with behavioural response to environmental variations. Respiratory frequency was the most sensitive index of goat response to climate. The daily increase of respiratory frequency was important at the end of the humid season but was not observed in dry season. This increase was dependent on ambient temperature increase but also on air humidity characteristics and air velocity. These points are discussed according to integration of those physiological parameters in thermoregulation.

Effect of driving voltages in dual capacitively coupled radio frequency plasma: A study by nonlinear global model

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

Bora, B., E-mail: bbora@cchen.cl

2015-10-15

On the basis of nonlinear global model, a dual frequency capacitively coupled radio frequency plasma driven by 13.56 MHz and 27.12 MHz has been studied to investigate the influences of driving voltages on the generation of dc self-bias and plasma heating. Fluid equations for the ions inside the plasma sheath have been considered to determine the voltage-charge relations of the plasma sheath. Geometrically symmetric as well as asymmetric cases with finite geometrical asymmetry of 1.2 (ratio of electrodes area) have been considered to make the study more reasonable to experiment. The electrical asymmetry effect (EAE) and finite geometrical asymmetry is found tomore » work differently in controlling the dc self-bias. The amount of EAE has been primarily controlled by the phase angle between the two consecutive harmonics waveforms. The incorporation of the finite geometrical asymmetry in the calculations shift the dc self-bias towards negative polarity direction while increasing the amount of EAE is found to increase the dc self-bias in either direction. For phase angle between the two waveforms ϕ = 0 and ϕ = π/2, the amount of EAE increases significantly with increasing the low frequency voltage, whereas no such increase in the amount of EAE is found with increasing high frequency voltage. In contrast to the geometrically symmetric case, where the variation of the dc self-bias with driving voltages for phase angle ϕ = 0 and π/2 are just opposite in polarity, the variation for the geometrically asymmetric case is different for ϕ = 0 and π/2. In asymmetric case, for ϕ = 0, the dc self-bias increases towards the negative direction with increasing both the low and high frequency voltages, but for the ϕ = π/2, the dc-self bias is increased towards positive direction with increasing low frequency voltage while dc self-bias increases towards negative direction with increasing high frequency voltage.« less

Alcohol use and drunk driving: the modifying effect of impulsivity.

PubMed

Moan, Inger Synnøve; Norström, Thor; Storvoll, Elisabet E

2013-01-01

The aim of this study was twofold: (a) to examine how an increase in the frequency of heavy drinking episodes affects the incidence of drunk driving and (b) to examine whether the effect of alcohol use on drunk driving is contingent on impulsivity. Two waves of the Young in Norway Longitudinal Study were applied (N = 2,603; response rate: 67%), when the respondents were on average 17 (1994) and 28 (2005) years of age. Measurements consisted of self-reported heavy episodic drinking, drunk driving, and impulsivity. The first difference method was applied to estimate the association between heavy episodic drinking and drunk driving. This means that changes in the frequency of drunk driving were regressed on changes in the frequency of drinking. In this way, the effects of time-invariant confounders were eliminated. The results showed that every additional episode of heavy drinking was associated with a 2.6% increase in the frequency of drunk driving. The increase for males was significantly higher than among females. The analyses supported the hypothesis that impulsivity modifies the association between alcohol use and drunk driving. The association between drinking and drunk driving is significantly stronger among those with a high score on impulsivity compared with those who have a low score.

The development and evaluation of ultrasound for the treatment of bacterial suspensions. A study of frequency, power and sonication time on cultured Bacillus species.

PubMed

Joyce, E; Phull, S S; Lorimer, J P; Mason, T J

2003-10-01

Some species of bacteria produce colonies and spores which agglomerate in spherical clusters (Bacillus subtilis) and this serves as a protection for the organisms inside against biocidal attack. Flocs of fine particles e.g. clay can entrap bacteria which can also protect them against the biocides. It is because of problems such as these that alternative methods of disinfecting water are under active investigation. One such method is the use of power ultrasound, either alone or in combination with other methods. Ultrasound is able to inactivate bacteria and deagglomerate bacterial clusters or flocs through a number of physical, mechanical and chemical effects arising from acoustic cavitation. The aim of this study was to investigate the effect of power ultrasound at different powers and frequencies on Bacillus subtilis. Viable plate count techniques were used as a measure of microbial activity. Results showed a significant increase in percent kill for Bacillus species with increasing duration of exposure and intensity of ultrasound in the low-kilohertz range (20 and 38 kHz). Results obtained at two higher frequencies (512 and 850 kHz) indicated a significant increase in bacteria count suggesting declumping. In assessing the bacterial kill with time under different sonication regimes three types of behaviour were characterized: High power ultrasound (lower frequencies) in low volumes of bacterial suspension results in a continuous reduction in bacterial cell numbers i.e. the kill rate predominates. High power ultrasound (lower frequencies) in larger volumes results in an initial rise in cell numbers suggesting declumping of the bacteria but this initial rise then falls as the declumping finishes and the kill rate becomes more important. Low intensity ultrasound (higher frequencies) gives an initial rise in cell numbers as a result of declumping. The kill rate is low and so there is no significant subsequent decrease in bacterial cell numbers.

Are changes in drinking related to changes in cannabis use among Swedish adolescents? A time-series analysis for the period 1989-2016.

PubMed

Gripe, Isabella; Danielsson, Anna-Karin; Ramstedt, Mats

2018-04-21

To examine if changes in alcohol consumption are associated with changes in cannabis use among Swedish adolescents in a period of diverging trends, and to investigate if cannabis and alcohol act as complements or substitutes. Data comprise a nationally representative annual school survey of alcohol and drug habits among Swedish 9th-grade students (aged 15-16 years) covering years 1989-2016 (n = 149 603). Alcohol and cannabis use were measured concurrently and alcohol consumption was measured in litres of 100% alcohol per year. Frequency of cannabis use was transformed into a mean using category mid-points. Autoregressive integrated moving average (ARIMA) time-series analysis was used to estimate the association between cannabis and alcohol use. To elucidate changes in the association during the study period, two subperiods (2000-16 and 1989-99) were analysed. There was a positive and statistically significant association between changes in alcohol consumption and changes in frequency of cannabis use among cannabis users for the period 1989-2016. A 1-litre increase in mean alcohol consumption was associated with a 0.28 increase in frequency of cannabis use (P = 0.010). The corresponding increase for the period 1989-99 was 0.52 (P = 0.003). When restricting the analysis to 2000-16, the association was not statistically significant (P = 0.735). When analysing all adolescents we found no statistically significant association between changes in alcohol consumption and changes in frequency of cannabis use. From 1989 to 2016 there appears to be a positive association between alcohol and cannabis consumption among Swedish adolescents who use cannabis. This association seems to have become weaker over time, suggesting that alcohol and cannabis are neither substitutes nor complements among Swedish adolescents and that the recent decline in youth drinking is not associated with the increase in frequency of cannabis use. © 2018 Society for the Study of Addiction.

Effect of higher frequency components and duration of vibration on bone tissue alterations in the rat-tail model

PubMed Central

PEELUKHANA, Srikara V.; GOENKA, Shilpi; KIM, Brian; KIM, Jay; BHATTACHARYA, Amit; STRINGER, Keith F.; BANERJEE, Rupak K.

2015-01-01

To formulate more accurate guidelines for musculoskeletal disorders (MSD) linked to Hand-Arm Vibration Syndrome (HAVS), delineation of the response of bone tissue under different frequencies and duration of vibration needs elucidation. Rat-tails were vibrated at 125 Hz (9 rats) and 250 Hz (9 rats), at 49 m/s2, for 1D (6 rats), 5D (6 rats) and 20D (6 rats); D=days (4 h/d). Rats in the control group (6 rats for the vibration groups; 2 each for 1D, 5D, and 20D) were left in their cages, without being subjected to any vibration. Structural and biochemical damages were quantified using empty lacunae count and nitrotyrosine signal-intensity, respectively. One-way repeated-measure mixed-model ANOVA at p<0.05 level of significance was used for analysis. In the cortical bone, structural damage quantified through empty lacunae count was significant (p<0.05) at 250 Hz (10.82 ± 0.66) in comparison to the control group (7.41 ± 0.76). The biochemical damage was significant (p<0.05) at both the 125 Hz and 250 Hz vibration frequencies. The structural damage was significant (p<0.05) at 5D for cortical bone while the trabecular bone showed significant (p<0.05) damage at 20D time point. Further, the biochemical damage increased with increase in the duration of vibration with a significant (p<0.05) damage observed at 20D time point and a near significant change (p=0.08) observed at 5D time point. Structural and biochemical changes in bone tissue are dependent upon higher vibration frequencies of 125 Hz, 250 Hz and the duration of vibration (5D, 20D). PMID:25843564

High Resolution Topography of Age-Related Changes in Non-Rapid Eye Movement Sleep Electroencephalography

PubMed Central

Sprecher, Kate E.; Riedner, Brady A.; Smith, Richard F.; Tononi, Giulio; Davidson, Richard J.; Benca, Ruth M.

2016-01-01

Sleeping brain activity reflects brain anatomy and physiology. The aim of this study was to use high density (256 channel) electroencephalography (EEG) during sleep to characterize topographic changes in sleep EEG power across normal aging, with high spatial resolution. Sleep was evaluated in 92 healthy adults aged 18–65 years old using full polysomnography and high density EEG. After artifact removal, spectral power density was calculated for standard frequency bands for all channels, averaged across the NREM periods of the first 3 sleep cycles. To quantify topographic changes with age, maps were generated of the Pearson’s coefficient of the correlation between power and age at each electrode. Significant correlations were determined by statistical non-parametric mapping. Absolute slow wave power declined significantly with increasing age across the entire scalp, whereas declines in theta and sigma power were significant only in frontal regions. Power in fast spindle frequencies declined significantly with increasing age frontally, whereas absolute power of slow spindle frequencies showed no significant change with age. When EEG power was normalized across the scalp, a left centro-parietal region showed significantly less age-related decline in power than the rest of the scalp. This partial preservation was particularly significant in the slow wave and sigma bands. The effect of age on sleep EEG varies substantially by region and frequency band. This non-uniformity should inform the design of future investigations of aging and sleep. This study provides normative data on the effect of age on sleep EEG topography, and provides a basis from which to explore the mechanisms of normal aging as well as neurodegenerative disorders for which age is a risk factor. PMID:26901503

Astrosat/LAXPC Reveals the High-energy Variability of GRS 1915+105 in the X Class

NASA Astrophysics Data System (ADS)

Yadav, J. S.; Misra, Ranjeev; Verdhan Chauhan, Jai; Agrawal, P. C.; Antia, H. M.; Pahari, Mayukh; Dedhia, Dhiraj; Katoch, Tilak; Madhwani, P.; Manchanda, R. K.; Paul, B.; Shah, Parag; Ishwara-Chandra, C. H.

2016-12-01

We present the first quick look analysis of data from nine AstroSat's Large Area X-ray Proportional Counter (LAXPC) observations of GRS 1915+105 during 2016 March when the source had the characteristics of being in the Radio-quiet χ class. We find that a simple empirical model of a disk blackbody emission, with Comptonization and a broad Gaussian Iron line can fit the time-averaged 3-80 keV spectrum with a systematic uncertainty of 1.5% and a background flux uncertainty of 4%. A simple dead time corrected Poisson noise level spectrum matches well with the observed high-frequency power spectra till 50 kHz and as expected the data show no significant high-frequency (\\gt 20 {Hz}) features. Energy dependent power spectra reveal a strong low-frequency (2-8 Hz) quasi-periodic oscillation and its harmonic along with broadband noise. The QPO frequency changes rapidly with flux (nearly 4 Hz in ˜5 hr). With increasing QPO frequency, an excess noise component appears significantly in the high-energy regime (\\gt 8 keV). At the QPO frequencies, the time-lag as a function of energy has a non-monotonic behavior such that the lags decrease with energy till about 15-20 keV and then increase for higher energies. These first-look results benchmark the performance of LAXPC at high energies and confirms that its data can be used for more sophisticated analysis such as flux or frequency-resolved spectro-timing studies.

Kindling alters entorhinal cortex-hippocampal interaction by increased efficacy of presynaptic GABA(B) autoreceptors in layer III of the entorhinal cortex.

PubMed

Gloveli, Tengis; Behr, Joachim; Dugladze, Tamar; Kokaia, Zaal; Kokaia, Merab; Heinemann, Uwe

2003-08-01

We studied the effect of kindling, a model of temporal lobe epilepsy, on the frequency-dependent information transfer from the entorhinal cortex to the hippocampus in vitro. In control rats repetitive synaptic activation of layer III projection cells resulted in a frequency dependent depression of the synaptic transfer of action potentials to the hippocampus. One-to-two-days after kindling this effect was strongly reduced. Although no substantial change in synaptic inhibition upon single electrical stimulation was detected in kindled rats, there was a significant depression in the prolonged inhibition following high frequency stimulation. In kindled animals, paired-pulse depression (PPD) of stimulus-evoked IPSCs in layer III neurons was significantly stronger than in control rats. The increase of PPD is most likely caused by an increased presynaptic GABA(B) receptor-mediated autoinhibition. In kindled animals activation of presynaptic GABA(B) receptors by baclofen (10 microM) suppressed monosynaptic IPSCs significantly more than in control rats. In contrast, activation of postsynaptic GABA(B) receptors by baclofen was accompanied by comparable changes of the membrane conductance in both animal groups. Thus, in kindled animals activation of the layer III-CA1 pathway is facilitated by an increased GABA(B) receptor-mediated autoinhibition leading to an enhanced activation of the monosynaptic EC-CA1 pathway.

Menstrual change during the menopause transition: do women find it problematic?

PubMed

Mackey, Sandra

2009-10-20

To describe changes in the characteristics of women's menstrual cycles during the menopause transition and to identify whether such changes are perceived by women as being problematic. A cross-sectional descriptive study using a community-based convenience sample of 119 women aged 37-70 years. Participants completed a questionnaire to obtain data on demographic characteristics, menopausal status and changes to menstrual flow, duration, frequency and regularity. There was a common pattern of menstrual change which was of heavier, less frequent, irregular menstruation. Forty one percent of post-menopausal and 40% of women still in the menopause transition stated that, in terms of overall perception, the changes to menstruation experienced during the menopause transition were not problematic or disruptive. When specific change characteristics were examined, significant differences were found in duration of menses (p=0.014) and cycle irregularity (p=0.005) but no significant differences were found on the amount of flow (p=0.125) or frequency of cycles (p=0.142). Increased duration and increased irregularity of occurrence of each period are problematic for women going through the menopause transition, however, increased amount of menstrual flow at each period and increased frequency of cycles are not problematic changes.

Effects of frequency on gross efficiency and performance in roller ski skating.

PubMed

Leirdal, S; Sandbakk, O; Ettema, G

2013-06-01

The purpose of the present study was to examine the effect of frequency on efficiency and performance during G3 roller ski skating. Eight well-trained male cross-country skiers performed three submaximal 5-min speeds (10, 13, and 16 km/h) and a time-to-exhaustion (TTE) performance (at 20 km/h) using the G3 skating technique using freely chosen, high, and low frequency at all four speeds. All tests were done using roller skis on a large treadmill at 5% incline. Gross efficiency (GE) was calculated as power divided by metabolic rate. Power was calculated as the sum of power against frictional forces and power against gravity. Metabolic rate was calculated from oxygen consumption and blood lactate concentration. Freely chosen frequency increased from 60 to 70 strokes/min as speed increased from 10 to 20 km/h. GE increased with power. At high power (20 km/h performance test), both efficiency and performance were significantly reduced by high frequency. In regard to choice of frequency during G3 roller ski skating, cross-country skiers seems to be self-optimized both in relation to energy saving (efficiency) and performance (TTE). © 2011 John Wiley & Sons A/S.

Gentamicin differentially alters cellular metabolism of cochlear hair cells as revealed by NAD(P)H fluorescence lifetime imaging

NASA Astrophysics Data System (ADS)

Zholudeva, Lyandysha V.; Ward, Kristina G.; Nichols, Michael G.; Smith, Heather Jensen

2015-05-01

Aminoglycoside antibiotics are implicated as culprits of hearing loss in more than 120,000 individuals annually. Research has shown that the sensory cells, but not supporting cells, of the cochlea are readily damaged and/or lost after use of such antibiotics. High-frequency outer hair cells (OHCs) show a greater sensitivity to antibiotics than high- and low-frequency inner hair cells (IHCs). We hypothesize that variations in mitochondrial metabolism account for differences in susceptibility. Fluorescence lifetime microscopy was used to quantify changes in NAD(P)H in sensory and supporting cells from explanted murine cochleae exposed to mitochondrial uncouplers, inhibitors, and an ototoxic antibiotic, gentamicin (GM). Changes in metabolic state resulted in a redistribution of NAD(P)H between subcellular fluorescence lifetime pools. Supporting cells had a significantly longer lifetime than sensory cells. Pretreatment with GM increased NAD(P)H intensity in high-frequency sensory cells, as well as the NAD(P)H lifetime within IHCs. GM specifically increased NAD(P)H concentration in high-frequency OHCs, but not in IHCs or pillar cells. Variations in NAD(P)H intensity in response to mitochondrial toxins and GM were greatest in high-frequency OHCs. These results demonstrate that GM rapidly alters mitochondrial metabolism, differentially modulates cell metabolism, and provides evidence that GM-induced changes in metabolism are significant and greatest in high-frequency OHCs.

Gentamicin differentially alters cellular metabolism of cochlear hair cells as revealed by NAD(P)H fluorescence lifetime imaging

PubMed Central

Zholudeva, Lyandysha V.; Ward, Kristina G.; Nichols, Michael G.; Smith, Heather Jensen

2015-01-01

Abstract. Aminoglycoside antibiotics are implicated as culprits of hearing loss in more than 120,000 individuals annually. Research has shown that the sensory cells, but not supporting cells, of the cochlea are readily damaged and/or lost after use of such antibiotics. High-frequency outer hair cells (OHCs) show a greater sensitivity to antibiotics than high- and low-frequency inner hair cells (IHCs). We hypothesize that variations in mitochondrial metabolism account for differences in susceptibility. Fluorescence lifetime microscopy was used to quantify changes in NAD(P)H in sensory and supporting cells from explanted murine cochleae exposed to mitochondrial uncouplers, inhibitors, and an ototoxic antibiotic, gentamicin (GM). Changes in metabolic state resulted in a redistribution of NAD(P)H between subcellular fluorescence lifetime pools. Supporting cells had a significantly longer lifetime than sensory cells. Pretreatment with GM increased NAD(P)H intensity in high-frequency sensory cells, as well as the NAD(P)H lifetime within IHCs. GM specifically increased NAD(P)H concentration in high-frequency OHCs, but not in IHCs or pillar cells. Variations in NAD(P)H intensity in response to mitochondrial toxins and GM were greatest in high-frequency OHCs. These results demonstrate that GM rapidly alters mitochondrial metabolism, differentially modulates cell metabolism, and provides evidence that GM-induced changes in metabolism are significant and greatest in high-frequency OHCs. PMID:25688541

Defibrotide in combination with granulocyte colony-stimulating factor significantly enhances the mobilization of primitive and committed peripheral blood progenitor cells in mice.

PubMed

Carlo-Stella, Carmelo; Di Nicola, Massimo; Magni, Michele; Longoni, Paolo; Milanesi, Marco; Stucchi, Claudio; Cleris, Loredana; Formelli, Franca; Gianni, Massimo A

2002-11-01

Defibrotide is a polydeoxyribonucleotide, which significantly reduces the expression of adhesion molecules on endothelial cells. We investigated the activity of Defibrotide alone or in combination with recombinant human granulocyte colony-stimulating factor (rhG-CSF) to mobilize peripheral blood progenitor cells (PBPCs) in BALB/c mice. A 5-day treatment with Defibrotide alone (1-15 mg/mouse/day) had no effect on WBC counts, frequencies and absolute numbers of total circulating colony-forming cells (CFCs), i.e., granulocyte-macrophage colony-forming units, erythroid burst-forming units, and multilineage colony-forming units. As compared with mock-injected mice, administration of rhG-CSF alone (5 micro g/mouse/day) for 5 days significantly (P < or = 0.0001) increased WBC counts, CFC frequencies, and CFC absolute numbers by 2-, 13-, and 27-fold, respectively. As compared with control mice, the combined administration of Defibrotide (15 mg/mouse/day) and rhG-CSF significantly (P < or = 0.0001) increased WBC counts, frequencies and absolute numbers of CFCs by 4-, 38-, and 119-fold, respectively. As compared with rhG-CSF alone, administration of Defibrotide plus rhG-CSF resulted in a significant increase (P < or = 0.001) of the frequency of circulating long-term culture-initiating cells. In addition, transplantation of 2 x 10(5) rhG-CSF- or Defibrotide/rhG-CSF-mobilized mononuclear cells rescued 43% and 71% of recipient mice, respectively. Experiments of CFC homing performed in lethally irradiated or nonirradiated recipients showed that marrow homing of transplanted PBPCs was reduced by 3-fold in Defibrotide-treated animals as compared with mock-injected mice (P < or = 0.001), suggesting that the mobilizing effect of Defibrotide might be because of an effect on PBPC trafficking. In conclusion, our data demonstrate that Defibrotide synergizes with rhG-CSF and significantly increases the mobilization of a broad spectrum of PBPCs, including primitive and committed progenitor cells. These data might have relevant implications for autologous and allogeneic anticancer therapy in humans.

Effect of traffic density on drivers' lane change and overtaking maneuvers in freeway situation - A driving simulator based study.

PubMed

Yang, Liu; Li, Xiaomeng; Guan, Wei; Zhang, H Michael; Fan, Lingling

2018-05-14

The aim of this study is to examine the effect of traffic density on drivers' lane change and overtaking maneuvers. The differences between drivers' left and right lane-changing/overtaking maneuvers were also investigated. A driving simulator experiment was conducted and 24 participants took part in this experiment. Based on the driving simulation data, lane change frequency, time duration, average speed and acceleration were extracted as key variables of lane change maneuvers; overtaking frequency, overtaking duration, initial overtaking distance and headway, instantaneous speed and acceleration before overtaking were analyzed as the key overtaking variables. One-way repeated measures ANOVA, Friedman test and Wilcoxon signed-rank test were adopted for hypothesis tests with significance level of 0.05. Further pairwise comparisons were performed with a Bonferroni correction for multiple comparisons. Some significant differences in lane change and overtake behaviors were observed among different traffic densities: 1) both lane change and overtaking frequencies significantly increase with traffic density; 2) the average lane change acceleration and instantaneous overtaking acceleration significantly increase with traffic density; 3) as the traffic density increases, the initial overtaking distance and headway decrease. As for the effect of the directions of maneuvers: 1) the time duration of lane change and overtaking from right side was significantly shorter than that from left side; 2) the right initial overtaking distance/headway was smaller than that of left side; 3) the right instantaneous overtaking acceleration was significantly higher than the left instantaneous acceleration. The results showed that as traffic density increases, drivers' intention for lane change and overtaking is enhanced. Both initial overtaking distance and headway decrease with traffic density, which might influence road safety. In addition, drivers do not show a preference on the directions of lane change or overtaking according to the frequency. However, drivers tend to be more decisive and reckless when conducting the right overtaking because of a smaller distance/headway before overtaking, higher instantaneous acceleration and also a more restricted field of view compared with left overtaking.

Sarcolipin overexpression improves muscle energetics and reduces fatigue

PubMed Central

Sopariwala, Danesh H.; Pant, Meghna; Shaikh, Sana A.; Goonasekera, Sanjeewa A.; Molkentin, Jeffery D.; Weisleder, Noah; Ma, Jianjie; Pan, Zui

2015-01-01

Sarcolipin (SLN) is a regulator of sarcoendoplasmic reticulum calcium ATPase in skeletal muscle. Recent studies using SLN-null mice have identified SLN as a key player in muscle thermogenesis and metabolism. In this study, we exploited a SLN overexpression (SlnOE) mouse model to determine whether increased SLN level affected muscle contractile properties, exercise capacity/fatigue, and metabolic rate in whole animals and isolated muscle. We found that SlnOE mice are more resistant to fatigue and can run significantly longer distances than wild-type (WT). Studies with isolated extensor digitorum longus (EDL) muscles showed that SlnOE EDL produced higher twitch force than WT. The force-frequency curves were not different between WT and SlnOE EDLs, but at lower frequencies the pyruvate-induced potentiation of force was significantly higher in SlnOE EDL. SLN overexpression did not alter the twitch and force-frequency curve in isolated soleus muscle. However, during a 10-min fatigue protocol, both EDL and soleus from SlnOE mice fatigued significantly less than WT muscles. Interestingly, SlnOE muscles showed higher carnitine palmitoyl transferase-1 protein expression, which could enhance fatty acid metabolism. In addition, lactate dehydrogenase expression was higher in SlnOE EDL, suggesting increased glycolytic capacity. We also found an increase in store-operated calcium entry (SOCE) in isolated flexor digitorum brevis fibers of SlnOE compared with WT mice. These data allow us to conclude that increased SLN expression improves skeletal muscle performance during prolonged muscle activity by increasing SOCE and muscle energetics. PMID:25701006

Effects of Parkinson's Disease on Fundamental Frequency Variability in Running Speech.

PubMed

Bowen, Leah K; Hands, Gabrielle L; Pradhan, Sujata; Stepp, Cara E

2013-09-01

In Parkinson's Disease (PD), qualitative speech changes such as decreased variation in pitch and loudness are common, but quantitative vocal changes are not well documented. The variability of fundamental frequency (F0) in 32 individuals (23 male) with PD both ON and OFF levodopa medication was compared with 32 age-matched healthy controls (23 male). Participants read a single paragraph and estimates of fundamental frequency (F0) variability were determined for the entire reading passage as well as for the first and last sentences of the passage separately. F0 variability was significantly increased in controls relative to both PD groups and PD patients showed significantly higher F0 variability while ON medication relative to OFF. No significant effect of group was seen in the change in F0 variability from the beginning to the end of the reading passage. Female speakers were found to have higher F0 variability than males. F0 variability was both significantly reduced in PD relative to controls and significantly increased in patients with PD during use of dopaminergic medications. F0 variability changes over the course of reading a paragraph may not be indicative of PD but rather dependent on non-disease factors such as the linguistic characteristics of the text.

Communication restriction in adults who stutter: Part II.

PubMed

Lee, Amanda; Robb, Michael; van Dulm, Ondene; Ormond, Tika

This article presents a follow-up study to Lee, van Dulm, Robb, and Ormond (2015). The aim was to explore communication restriction in adults with stuttering (AWS) using typical language measures and systemic functional linguistics (SFL) analyses. The article compared the pre- and post-treatment performance of AWS in language productivity and complexity, transitivity, modality, appraisal, and theme. Ten-minute conversational samples were obtained from 20 AWS before and after participation in intensive stuttering treatment. Transcripts were analysed for quantity and complexity of verbal output, and frequency of transitivity, modality, appraisal and theme resources. Between pre- and post-treatment, the following differences were observed: (1) a significant increase in frequency of modal operators, and trends approaching significance for (2) increased language complexity (3) increased language expressing appraisal. These changes suggest increased flexibility of language use in AWS following treatment, particularly towards interpersonal engagement. The value of SFL to this area of research is discussed.

Characteristics of genomic instability in clones of TK6 human lymphoblasts surviving exposure to 56Fe ions

NASA Technical Reports Server (NTRS)

Evans, Helen H.; Horng, Min-Fen; Ricanati, Marlene; Diaz-Insua, Mireya; Jordan, Robert; Schwartz, Jeffrey L.

2002-01-01

Genomic instability in the human lymphoblast cell line TK6 was studied in clones surviving 36 generations after exposure to accelerated 56Fe ions. Clones were assayed for 20 characteristics, including chromosome aberrations, plating efficiency, apoptosis, cell cycle distribution, response to a second irradiation, and mutant frequency at two loci. The primary effect of the 56Fe-ion exposure on the surviving clones was a significant increase in the frequency of unstable chromosome aberrations compared to the very low spontaneous frequency, along with an increase in the phenotypic complexity of the unstable clones. The radiation-induced increase in the frequency of unstable chromosome aberrations was much greater than that observed previously in clones of the related cell line, WTK1, which in comparison to the TK6 cell line expresses an increased radiation resistance, a mutant TP53 protein, and an increased frequency of spontaneous unstable chromosome aberrations. The characteristics of the unstable clones of the two cell lines also differed. Most of the TK6 clones surviving exposure to 56Fe ions showed unstable cytogenetic abnormalities, while the phenotype of the WTK1 clones was more diverse. The results underscore the importance of genotype in the characteristics of instability after radiation exposure.

Is grand multiparity a risk factor for the development of postmenopausal osteoporosis?

PubMed Central

Peker, Nuri; Tosun, Özge Çeliker

2018-01-01

Objective In this study, we investigated the relationship between the development of postmenopausal osteoporosis and parity. Materials and methods The retrospective study included 129 postmenopausal women who were divided into three groups depending on the number of parity: Group I, <5; Group II, 5–9; and Group III, ≥10. The mean age of the subjects was 57.71±5.02 years. Results No significant difference was found among the three groups regarding body mass index values, duration of menopause, mean thyroid stimulating hormone values and frequency of diabetes. Among the three groups, no significant difference was found in terms of the frequency of lumbar osteoporosis (p>0.05), whereas a significant difference was found regarding the frequency of femoral osteoporosis (p=0.012; p<0.05). Conclusion It was revealed that femoral bone mineral density significantly decreased as the number of parity increased. PMID:29636605

Social and emotional patterns in adulthood: support for socioemotional selectivity theory.

PubMed

Carstensen, L L

1992-09-01

This investigation explored 2 hypotheses derived from socioemotional selectivity theory: (a) Selective reductions in social interaction begin in early adulthood and (b) emotional closeness to significant others increases rather than decreases in adulthood even when rate reductions occur. Transcribed interviews with 28 women and 22 men from the Child Guidance Study, conducted over 34 years, were reviewed and rated for frequency of interaction, satisfaction with the relationship, and degree of emotional closeness in 6 types of relationships. Interaction frequency with acquaintances and close friends declined from early adulthood on. Interaction frequency with spouses and siblings increased across the same time period and emotional closeness increased throughout adulthood in relationships with relatives and close friends. Findings suggest that individuals begin narrowing their range of social partners long before old age.

Tong Xie Yao Fang relieves irritable bowel syndrome in rats via mechanisms involving regulation of 5-hydroxytryptamine and substance P

PubMed Central

Yin, Yue; Zhong, Lei; Wang, Jian-Wei; Zhao, Xue-Ying; Zhao, Wen-Jing; Kuang, Hai-Xue

2015-01-01

AIM: To investigate whether the Chinese medicine Tong Xie Yao Fang (TXYF) improves dysfunction in an irritable bowel syndrome (IBS) rat model. METHODS: Thirty baby rats for IBS modeling were separated from mother rats (1 h per day) from days 8 to 21, and the rectum was expanded by angioplasty from days 8 to 12. Ten normal rats were used as normal controls. We examined the effects of TXYF on defection frequency, colonic transit function and smooth muscle contraction, and the expression of 5-hydroxytryptamine (5-HT) and substance P (SP) in colonic and hypothalamus tissues by Western blot and RT-PCT techniques in both normal rats and IBS model rats with characterized visceral hypersensitivity. RESULTS: Defecation frequency was 1.8 ± 1.03 in normal rats and 4.5 ± 1.58 in IBS model rats (P < 0.001). However, the defecation frequency was significantly decreased (3.0 ± 1.25 vs 4.5 ± 1.58, P < 0.05), while the time (in seconds) of colon transit function was significantly increased (256.88 ± 20.32 vs 93.36 ± 17.28, P < 0.001) in IBS + TXYF group rats than in IBS group rats. Increased colonic smooth muscle tension and contract frequency in IBS model rats were significantly decreased by administration of TXYF. Exogenous agonist stimulants increased spontaneous activity and elicited contractions of colon smooth muscle in IBS model rats, and all of these actions were significantly reduced by TXYF involving 5-HT and SP down-regulation. CONCLUSION: TXYF can modulate the activity of the enteric nervous system and alter 5-HT and SP activities, which may contribute to the symptoms of IBS. PMID:25914462

Tong Xie Yao Fang relieves irritable bowel syndrome in rats via mechanisms involving regulation of 5-hydroxytryptamine and substance P.

PubMed

Yin, Yue; Zhong, Lei; Wang, Jian-Wei; Zhao, Xue-Ying; Zhao, Wen-Jing; Kuang, Hai-Xue

2015-04-21

To investigate whether the Chinese medicine Tong Xie Yao Fang (TXYF) improves dysfunction in an irritable bowel syndrome (IBS) rat model. Thirty baby rats for IBS modeling were separated from mother rats (1 h per day) from days 8 to 21, and the rectum was expanded by angioplasty from days 8 to 12. Ten normal rats were used as normal controls. We examined the effects of TXYF on defection frequency, colonic transit function and smooth muscle contraction, and the expression of 5-hydroxytryptamine (5-HT) and substance P (SP) in colonic and hypothalamus tissues by Western blot and RT-PCT techniques in both normal rats and IBS model rats with characterized visceral hypersensitivity. Defecation frequency was 1.8 ± 1.03 in normal rats and 4.5 ± 1.58 in IBS model rats (P < 0.001). However, the defecation frequency was significantly decreased (3.0 ± 1.25 vs 4.5 ± 1.58, P < 0.05), while the time (in seconds) of colon transit function was significantly increased (256.88 ± 20.32 vs 93.36 ± 17.28, P < 0.001) in IBS + TXYF group rats than in IBS group rats. Increased colonic smooth muscle tension and contract frequency in IBS model rats were significantly decreased by administration of TXYF. Exogenous agonist stimulants increased spontaneous activity and elicited contractions of colon smooth muscle in IBS model rats, and all of these actions were significantly reduced by TXYF involving 5-HT and SP down-regulation. TXYF can modulate the activity of the enteric nervous system and alter 5-HT and SP activities, which may contribute to the symptoms of IBS.

Characteristics of the surface plasma wave in a self-gravitating magnetized dusty plasma slab

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

Lee, Myoung-Jae; Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr; Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 15588

2015-11-15

The dispersion properties of surface dust ion-acoustic waves in a self-gravitating magnetized dusty plasma slab are investigated. The dispersion relation is derived by using the low-frequency magnetized dusty dielectric function and the surface wave dispersion integral for the slab geometry. We find that the self-gravitating effect suppresses the frequency of surface dust ion-acoustic wave for the symmetric mode in the long wavelength regime, whereas it hardly changes the frequency for the anti-symmetric mode. As the slab thickness and the wave number increase, the surface wave frequency slowly decreases for the symmetric mode but increases significantly for the anti-symmetric mode. Themore » influence of external magnetic field is also investigated in the case of symmetric mode. We find that the strength of the magnetic field enhances the frequency of the symmetric-mode of the surface plasma wave. The increase of magnetic field reduces the self-gravitational effect and thus the self-gravitating collapse may be suppressed and the stability of dusty objects in space is enhanced.« less

Climate change is projected to have severe impacts on the frequency and intensity of peak electricity demand across the United States

PubMed Central

Auffhammer, Maximilian; Baylis, Patrick; Hausman, Catherine H.

2017-01-01

It has been suggested that climate change impacts on the electric sector will account for the majority of global economic damages by the end of the current century and beyond [Rose S, et al. (2014) Understanding the Social Cost of Carbon: A Technical Assessment]. The empirical literature has shown significant increases in climate-driven impacts on overall consumption, yet has not focused on the cost implications of the increased intensity and frequency of extreme events driving peak demand, which is the highest load observed in a period. We use comprehensive, high-frequency data at the level of load balancing authorities to parameterize the relationship between average or peak electricity demand and temperature for a major economy. Using statistical models, we analyze multiyear data from 166 load balancing authorities in the United States. We couple the estimated temperature response functions for total daily consumption and daily peak load with 18 downscaled global climate models (GCMs) to simulate climate change-driven impacts on both outcomes. We show moderate and heterogeneous changes in consumption, with an average increase of 2.8% by end of century. The results of our peak load simulations, however, suggest significant increases in the intensity and frequency of peak events throughout the United States, assuming today’s technology and electricity market fundamentals. As the electricity grid is built to endure maximum load, our findings have significant implications for the construction of costly peak generating capacity, suggesting additional peak capacity costs of up to 180 billion dollars by the end of the century under business-as-usual. PMID:28167756

Lubiprostone increases spontaneous bowel movement frequency and quality of life in patients with chronic idiopathic constipation.

PubMed

Fukudo, Shin; Hongo, Michio; Kaneko, Hiroshi; Takano, Masahiro; Ueno, Ryuji

2015-02-01

Lubiprostone is an activator of the type 2 chloride channel that facilitates spontaneous bowel movement (SBM). We performed phase 3 studies to determine whether lubiprostone increases the frequency of SBM in patients with chronic idiopathic constipation (CIC) in Japan, and whether long-term administration of lubiprostone increases the quality of life of patients with CIC. We performed a randomized, double-blind, placebo-controlled, phase 3 trial of lubiprostone. Patients with CIC (n = 124) were assigned randomly to groups given placebo (n = 62) or lubiprostone (48 μg/day; n = 62) for 4 weeks. The primary efficacy end point was the change from baseline in the weekly average number of SBMs after 1 week of administration. In a long-term study of efficacy and safety, 209 patients with CIC were given lubiprostone (24 μg twice daily) for 48 weeks. Daily administration of lubiprostone induced a significantly greater change, from baseline, in the weekly average number of SBMs at week 1 (increase of 3.7 ± 2.8), compared with placebo (increase of 1.3 ± 1.8; P < .001). The frequency of SBMs during each week of the study period was significantly higher after subjects began receiving lubiprostone than at baseline (P < .0001 at all weeks). Long-term administration of lubiprostone significantly increased scores from the Short-Form health survey and irritable bowel syndrome quality-of-life questionnaire, compared with baseline. We did not observe any severe adverse reactions to lubiprostone. In phase 3 studies in Japan, lubiprostone increased the weekly average number of SBMs and increased the quality of life of patients with CIC. Clinical Trial Notification of the Japanese Regulatory Authorities: 20-3296 and 20-3300. Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.

Influence of the viscoelastic properties of the respiratory system on the energetically optimum breathing frequency.

PubMed

Bates, J H; Milic-Emili, J

1993-01-01

We hypothesized that the viscoelastic properties of the respiratory system should have significant implications for the energetically optimal frequency of breathing, in view of the fact that these properties cause marked dependencies of overall system resistance and elastance on frequency. To test our hypothesis we simulated two models of canine and human respiratory system mechanics during sinusoidal breathing and calculated the inspiratory work (WI) and pressure-time integral (PTI) per minute under both resting and exercise conditions. The two models were a two-compartment viscoelastic model and a single-compartment model. Requiring minute alveolar ventilation to be fixed, we found that both models predicted almost identical optimum breathing frequencies. The calculated PTI was very insensitive to increases in breathing frequency above the optimal frequencies, while WI was found to increase slowly with frequency above its optimum. In contrast, both WI and PTI increased sharply as frequency decreased below their respective optima. A sensitivity analysis showed that the model predictions were very insensitive to the elastance and resistance values chosen to characterize tissue viscoelasticity. We conclude that the WI criterion for choosing the frequency of breathing is compatible with observations in nature, whereas the optimal frequency predictions of the PTI are rather too high. Both criteria allow for a fairly wide margin of choice in frequency above the optimum values without incurring excessive additional energy expenditure. Furthermore, contrary to our expectations, the viscoelastic properties of the respiratory system tissues do not pose a noticeable problem to the respiratory controller in terms of energy expenditure.

Chirping response of weakly electric knife fish (Apteronotus leptorhynchus) to low-frequency electric signals and to heterospecific electric fish.

PubMed

Dunlap, K D; DiBenedictis, B T; Banever, S R

2010-07-01

Brown ghost knife fish (Apteronotus leptorhynchus) can briefly increase their electric organ discharge (EOD) frequency to produce electrocommunication signals termed chirps. The chirp rate increases when fish are presented with conspecific fish or high-frequency (700-1100 Hz) electric signals that mimic conspecific fish. We examined whether A. leptorhynchus also chirps in response to artificial low-frequency electric signals and to heterospecific electric fish whose EOD contains low-frequency components. Fish chirped at rates above background when presented with low-frequency (10-300 Hz) sine-wave stimuli; at 30 and 150 Hz, the threshold amplitude for response was 1 mV cm(-1). Low-frequency (30 Hz) stimuli also potentiated the chirp response to high-frequency ( approximately 900 Hz) stimuli. Fish increased their chirp rate when presented with two heterospecific electric fish, Sternopygus macrurus and Brachyhypopomus gauderio, but did not respond to the presence of the non-electric fish Carassius auratus. Fish chirped to low-frequency (150 Hz) signals that mimic those of S. macrurus and to EOD playbacks of B. gauderio. The response to the B. gauderio playback was reduced when the low-frequency component (<150 Hz) was experimentally filtered out. Thus, A. leptorhynchus appears to chirp specifically to the electric signals of heterospecific electric fish, and the low-frequency components of heterospecific EODs significantly influence chirp rate. These results raise the possibility that chirps function to communicate to conspecifics about the presence of a heterospecific fish or to communicate directly to heterospecific fish.

[Frequency of chromosome aberrations in residents of the Semipalatinsk Oblast].

PubMed

Gubitskaia, E G; Akhmatullina, N B; Vsevolodov, E B; Bishnevskaia, S S; Sharipov, I K; Cherednichenko, O G

1999-06-01

Cytogenetic analysis of the population of the Beskaragai district of the Semipalatinsk oblast adjacent to the territory of the nuclear test site was conducted by means of an ecological genetic questionnaire and cytogenetic examination of metaphase chromosomes. An increase in the total mutation level in the region was observed. The frequency of chromosome aberrations among the population of the Beskaragai district (3.2%) was statistically significantly (about 1.5 times) higher than the background levels in the clear regions (from 1 to 2%). Furthermore, the frequency of aberrations in adolescents was comparable with that in the adults. The spectrum of chromosome aberrations pointed to a significant contribution of radiation component to the mutagenesis.

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.

Thrust Measurement of Dielectric Barrier Discharge (DBD) Plasma Actuators: New Anti-Thrust Hypothesis, Frequency Sweeps Methodology, Humidity and Enclosure Effects

NASA Technical Reports Server (NTRS)

Ashpis, David E.; Laun, Matthew C.

2014-01-01

We discuss thrust measurements of Dielectric Barrier Discharge (DBD) plasma actuators devices used for aerodynamic active flow control. After a review of our experience with conventional thrust measurement and significant non-repeatability of the results, we devised a suspended actuator test setup, and now present a methodology of thrust measurements with decreased uncertainty. The methodology consists of frequency scans at constant voltages. The procedure consists of increasing the frequency in a step-wise fashion from several Hz to the maximum frequency of several kHz, followed by frequency decrease back down to the start frequency of several Hz. This sequence is performed first at the highest voltage of interest, then repeated at lower voltages. The data in the descending frequency direction is more consistent and selected for reporting. Sample results show strong dependence of thrust on humidity which also affects the consistency and fluctuations of the measurements. We also observed negative values of thrust, or "anti-thrust", at low frequencies between 4 Hz and up to 64 Hz. The anti-thrust is proportional to the mean-squared voltage and is frequency independent. Departures from the parabolic anti-thrust curve are correlated with appearance of visible plasma discharges. We propose the anti-thrust hypothesis. It states that the measured thrust is a sum of plasma thrust and anti-thrust, and assumes that the anti-thrust exists at all frequencies and voltages. The anti-thrust depends on actuator geometry and materials and on the test installation. It enables the separation of the plasma thrust from the measured total thrust. This approach enables more meaningful comparisons between actuators at different installations and laboratories. The dependence on test installation was validated by surrounding the actuator with a grounded large-diameter metal sleeve. Strong dependence on humidity is also shown; the thrust significantly increased with decreasing humidity, e.g., 44 percent increase as relative humidity changed from 18 percent and dew point 33 degF to 50 percent and dew point of 57 degF.

A Seven-Year Longitudinal Claim Analysis to Assess the Factors Contributing to the Increased Severity of Work-Related Injuries.

PubMed

Kalia, Nimisha; Lavin, Robert A; Yuspeh, Larry; Bernacki, Edward J; Tao, Xuguang Grant

2016-09-01

In recent decades, the frequency of Medical Only (MO) and Lost Time (LT) workers' compensation claims has decreased, while average severity (medical and indemnity costs) has increased. The aim of this study was to compare claim frequency, mix, and severity (cost) over two periods using a claim cohort follow-up method. Sixty-two thousand five hundred thirty-three claims during two periods (1999 to 2002 and 2003 to 2006) were followed seven years postinjury. Descriptive analysis and significant testing methods were used to compare claim frequency and costs. The number of claims per $1 M of premium decreased 50.4% for MO claims and 35.6% for LT claims, consequently increasing the LT claim proportion. The average cost of LT claims did not increase. The severity increase is attributable to the proportional change in LT and MO claims. While the number of LT claims decreased, the inflation-adjusted average cost of LT claims did not increase.

Investigating the relationship between jobs-housing balance and traffic safety.

PubMed

Xu, Chengcheng; Li, Haojie; Zhao, Jingya; Chen, Jun; Wang, Wei

2017-10-01

This study aimed to investigate the effects of jobs-housing balance on traffic safety. The crash, demographic characteristics, employment, road network, household characteristics and traffic data were collected from the Los Angeles in 2010. One-way ANOVA tests indicated that the jobs-housing ratio significantly affects traffic safety in terms of crash frequency at traffic analysis zone (TAZ). To quantify the safety impacts of jobs-housing balance, the semi-parametric geographically weighted Poisson regression (S-GWPR) was further used to link crash frequency at TAZ with jobs-housing ratio and other contributing factors. The S-GWPR provides better fitness to the data than do the generalized linear regression, as the S-GWPR accounts for the spatial heterogeneity. The S-GWPR results showed that the jobs-housing relationship has a significant association with crash frequency at TAZ when the factors of traffic, network, and household characteristics are controlled. Crash frequency at TAZ level increases with an increase in the jobs-housing ratio. To further investigate the interactive effects between jobs-housing ratio and other factors, a comparative analysis was conducted to compare the variable elasticities under different jobs-housing ratios. The results indicate considerable interactive effects that traffic conditions and road network characteristics have different effects on crash frequency under various jobs-housing ratios. Copyright © 2017 Elsevier Ltd. All rights reserved.

Neurological Adverse Effects in Patients of Advanced Colorectal Carcinoma Treated with Different Schedules of FOLFOX

PubMed Central

Najam, Rahila; Mateen, Ahmed

2013-01-01

The study is designed to assess the frequency and severity of few dose limiting neurological adverse effects of four different schedules of FOLFOX. Patients with histologically confirmed advanced colorectal carcinoma (CRC) were included in the study. Toxicity was graded according to CTC v 2.0. The frequency of grade 3 and 4 adverse effects was comparatively assessed in each treatment arm. The difference in the pattern of toxicity between the treatment schedule was evaluated. The most frequent adverse symptom of neurological adverse effect was grade 1 paresthesia in the patients treated with FOLFOX4 schedule. Grade 4 peripheral neuropathy was reported in few patients of FOLFOX7 treatment arm. Frequency and onset of neurological adverse effects like paresthesia, dizziness, and hypoesthesia were significantly different (P < 0.05), whereas frequency and onset of peripheral neuropathy were highly significant (P < 0.01) in each treatment arm of FOLFOX. Peripheral neuropathy was associated with electrolyte imbalance and diabetes in few patients. Frequency of symptoms, for example, paresthesia, is associated with increased number of recurrent exposure to oxaliplatin (increased number of cycles) even at low doses (85 mg/m2), whereas severity of symptoms, for example, peripheral neuropathy, is associated with higher dose (130 mg/m2) after few treatment cycles. PMID:24187619

A further examination of word frequency and age-of-acquisition effects in English lexical decision task performance: The role of frequency trajectory.

PubMed

Juhasz, Barbara J; Yap, Melvin J; Raoul, Akila; Kaye, Micaela

2018-04-23

Word frequency is an important predictor of lexical-decision task performance. The current study further examined the role of this variable by exploring the influence of frequency trajectory. Frequency trajectory is measured by how often a word occurs in childhood relative to adulthood. Past research on the role of this variable in word recognition has produced equivocal results. In the current study, words were selected based on their frequencies in Grade 1 (child frequency) and Grade 13 (college frequency). In Experiment 1, four frequency trajectory conditions were factorially examined in a lexical-decision task with English words: high-to-high (world), high-to-low (uncle), low-to-high (brain) and low-to-low (opera). an interaction between Grade 1 and college frequency demonstrated that words in the low-to-high condition were processed significantly faster and more accurately than words in the low-to-low condition, whereas the high-to-high and high-to-low conditions did not differ significantly. In Experiment 2, an advantage for words with an increasing frequency trajectory was also supported in regression analyses on both lexical decision and naming times for 3,039 items selected from the English Lexicon Project (Balota et al., 2007). This was replicated in Experiment 3, based on a regression analysis of 2,680 words from the British Lexicon Project (BLP; Keuleers, Lacey, Rastle, & Brysbaert, 2012). In all analyses, rated age-of-acquisition also significantly impacted word recognition. Together, the results suggest that the age at which a word is initially learned as well as its frequency trajectory across childhood impact performance in the lexical-decision task. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Effects of apolipoprotein E genotype on cortical neuropathology in senile dementia of the Lewy body and Alzheimer's disease.

PubMed

Benjamin, R; Leake, A; Ince, P G; Perry, R H; McKeith, I G; Edwardson, J A; Morris, C M

1995-12-01

Apolipoprotein E (APO E) genotypes were determined in a UK population of neuropathologically confirmed control cases, and in cases of Lewy body dementia (SDLT) and late onset Alzheimer's disease (AD). APO E epsilon 4 allele frequency was significantly elevated in both SDLT and AD groups with a concomitant reduction in the APO E epsilon 3 allele frequency. The epsilon 2 allele frequency in the AD group was only 25% of the control population, though because of the relatively small sample size this reduction was not significant; the epsilon 2 allele frequency in the SDLT group was normal. No significant association was found between senile plaque density and neurofibrillary tangle density in the neocortex and APO E allele dose in either SDLT or AD. Although the possession of APO E epsilon 4 is associated with an increased risk of developing SDLT and AD, actual APO E genotype does not appear to affect the burden of pathology.

[Assessment of influence of breath holding and hyperventilation on human postural stability with spectral analysis of stabilographic signal].

PubMed

Malakhov, M V; Makarenkova, E A; Mel'nikov, A A; Vikulov, A D

2014-01-01

The influence of breath holding and voluntary hyperventilation on the classic stabilometric parameters and the frequency characteristic of stabilographic signal were studied. We measured the stabilometric parameters on the force platform ("Ritm", Russia) on the healthy volunteers (n = 107) during quiet breath, voluntary hyperventilation (20 seconds) and maximal inspiratory breath holding (20 seconds). Respiratory frequency, respiratory amplitude and ventilation were estimated with strain gauge. We found that antero-posterior and medio-lateral sway amplitude and velocity as well as sway surface at breath-holding and at quiet breathing were the same, so breath holding didn't influence the postural stability. However the spectral parameters shifted to the high frequency range due to alteration of the respiratory muscles contractions during breath-holding versus quiet breath. Voluntary hyperventilation caused significant increase of all stabilographic indices that implied an impairment of postural stability, which was due to the increase of respiration frequency and amplitude. We also found that the spectral indices moved toward the high-frequency range with more pronounced degree of this shift versus breath holding. Besides, amplitudes of spectral peaks also increased. Perhaps such change of spectral indices was due to distortion of proprioceptive information because of increased excitability of nerve fibers during hyperventilation. Maximal inspiration breath holding causes strain of the postural control mechanisms that is reflected as elevation of postural sway frequency with no postural stability changes. Hyperventilation leads to the most prominent strain of balance function and decrease of steadiness that is manifested as increase of center of pressure oscillations amplitude and frequency.

Inhalation Frequency Controls Reformatting of Mitral/Tufted Cell Odor Representations in the Olfactory Bulb.

PubMed

Díaz-Quesada, Marta; Youngstrom, Isaac A; Tsuno, Yusuke; Hansen, Kyle R; Economo, Michael N; Wachowiak, Matt

2018-02-28

In mammals, olfactory sensation depends on inhalation, which controls activation of sensory neurons and temporal patterning of central activity. Odor representations by mitral and tufted (MT) cells, the main output from the olfactory bulb (OB), reflect sensory input as well as excitation and inhibition from OB circuits, which may change as sniff frequency increases. To test the impact of sampling frequency on MT cell odor responses, we obtained whole-cell recordings from MT cells in anesthetized male and female mice while varying inhalation frequency via tracheotomy, allowing comparison of inhalation-linked responses across cells. We characterized frequency effects on MT cell responses during inhalation of air and odorants using inhalation pulses and also "playback" of sniffing recorded from awake mice. Inhalation-linked changes in membrane potential were well predicted across frequency from linear convolution of 1 Hz responses; and, as frequency increased, near-identical temporal responses could emerge from depolarizing, hyperpolarizing, or multiphasic MT responses. However, net excitation was not well predicted from 1 Hz responses and varied substantially across MT cells, with some cells increasing and others decreasing in spike rate. As a result, sustained odorant sampling at higher frequencies led to increasing decorrelation of the MT cell population response pattern over time. Bulk activation of sensory inputs by optogenetic stimulation affected MT cells more uniformly across frequency, suggesting that frequency-dependent decorrelation emerges from odor-specific patterns of activity in the OB network. These results suggest that sampling behavior alone can reformat early sensory representations, possibly to optimize sensory perception during repeated sampling. SIGNIFICANCE STATEMENT Olfactory sensation in mammals depends on inhalation, which increases in frequency during active sampling of olfactory stimuli. We asked how inhalation frequency can shape the neural coding of odor information by recording from projection neurons of the olfactory bulb while artificially varying odor sampling frequency in the anesthetized mouse. We found that sampling an odor at higher frequencies led to diverse changes in net responsiveness, as measured by action potential output, that were not predicted from low-frequency responses. These changes led to a reorganization of the pattern of neural activity evoked by a given odorant that occurred preferentially during sustained, high-frequency inhalation. These results point to a novel mechanism for modulating early sensory representations solely as a function of sampling behavior. Copyright © 2018 the authors 0270-6474/18/382189-18$15.00/0.

Factors affecting smoking in schizophrenia.

PubMed

Beratis, S; Katrivanou, A; Gourzis, P

2001-01-01

There is an increased frequency of smoking among patients with schizophrenia. However, it is unknown whether the smoking behavior of the patients is similar in all schizophrenia subtypes, as well as which is the relationship between smoking initiation and disease onset. Four hundred six patients with DSM-IV schizophrenia were interviewed to determine the smoking status in relationship to gender and schizophrenic subtype, and to other factors that could affect or be affected by smoking. The frequency of smoking among patients (58%) was significantly greater than in subjects from the general population (42%) (P =.000005). Male patients smoked significantly more frequently (70%) than the corresponding control subjects (50%) (P =.000006), whereas the difference failed to reach significance between female patients (41%) and control subjects (32%). Among male patients, the number of smokers was significantly greater than in the controls in the paranoid (77%), undifferentiated (72%), and residual (78%) subtypes, whereas there was no significant difference in the disorganized (44%) and catatonic (22%) subtypes. The findings show that the frequency of smoking in schizophrenia patients increases with increasing positive symptoms and decreases with increasing negative symptoms. Male and female smoking patients consumed approximately 10 cigarettes per day more than the corresponding control subjects (P <.000001). In 86% of the patients, smoking initiation occurred before the disease onset. Among patients who smoked, smoking initiation and disease onset occurred at age 18.7 +/- 4.4 and 24.1 +/- 6.1 years, respectively (P <.000001). It appears that smoking in schizophrenia is influenced by gender and subtype. However, the nature of this association remains uncertain because in the vast majority of the patients smoking initiation occurs earlier than the disease onset. Copyright 2001 by W.B. Saunders Company

Rapid estimation of frequency response functions by close-range photogrammetry

NASA Technical Reports Server (NTRS)

Tripp, J. S.

1985-01-01

The accuracy of a rapid method which estimates the frequency response function from stereoscopic dynamic data is computed. It is shown that reversal of the order of the operations of coordinate transformation and Fourier transformation, which provides a significant increase in computational speed, introduces error. A portion of the error, proportional to the perturbation components normal to the camera focal planes, cannot be eliminated. The remaining error may be eliminated by proper scaling of frequency data prior to coordinate transformation. Methods are developed for least squares estimation of the full 3x3 frequency response matrix for a three dimensional structure.

How pH, Temperature, and Time of Incubation Affect False-Positive Responses and Uncertainty of the LAL Gel-Clot Test.

PubMed

Lourenço, Felipe Rebello; Botelho, Túlia De Souza; Pinto, Terezinha De Jesus Andreoli

2012-01-01

The limulus amebocyte lysate (LAL) test is the simplest and most widely used procedure for detection of endotoxin in parenteral drugs. The LAL test demands optimal pH, ionic strength, temperature, and time of incubation. Slight changes in these parameters may increase the frequency of false-positive responses and the estimated uncertainty of the LAL test. The aim of this paper is to evaluate how changes in the pH, temperature, and time of incubation affect the occurrence of false-positive responses in the LAL test. LAL tests were performed in nominal conditions (37 °C, 60 min, and pH 7) and in different conditions of temperature (36 °C and 38 °C), time of incubation (58 and 62 min), and pH (6 and 8). Slight differences in pH increase the frequency of false-positive responses 5-fold (relative risk 5.0), resulting in an estimated of uncertainty 7.6%. Temperature and time of incubation affect the LAL test less, showing relative risks of 1.5 and 1.0, respectively. Estimated uncertainties in 36 °C or 38 °C temperatures and 58 or 62 min of incubation were found to be 2.0% and 1.0%, respectively. Simultaneous differences in these parameters significantly increase the frequency of false-positive responses. The limulus amebocyte lysate (LAL) gel-clot test is a simple test for detection of endotoxin from Gram-negative bacteria. The test is based on a gel formation when a certain amount of endotoxin is present; it is a pass/fail test. The LAL test requires optimal pH, ionic strength, temperature, and time of incubation. Slight difference in these parameters may increase the frequency of false-positive responses. The aim of this paper is to evaluate how changes in the pH, temperature, and time of incubation affect the occurrence of false-positive responses in the LAL test. We find that slight differences in pH increase the frequency of false-positive responses 5-fold. Temperature and time of incubation affect the LAL test less. Simultaneous differences in these parameters significantly increase the frequency of false-positive responses.

Magnesium Increases Homoeologous Crossover Frequency During Meiosis in ZIP4 (Ph1 Gene) Mutant Wheat-Wild Relative Hybrids.

PubMed

Rey, María-Dolores; Martín, Azahara C; Smedley, Mark; Hayta, Sadiye; Harwood, Wendy; Shaw, Peter; Moore, Graham

2018-01-01

Wild relatives provide an important source of useful traits in wheat breeding. Wheat and wild relative hybrids have been widely used in breeding programs to introduce such traits into wheat. However, successful introgression is limited by the low frequency of homoeologous crossover (CO) between wheat and wild relative chromosomes. Hybrids between wheat carrying a 70 Mb deletion on chromosome 5B ( ph1b ) and wild relatives, have been exploited to increase the level of homoeologous CO, allowing chromosome exchange between their chromosomes. In ph1b -rye hybrids, CO number increases from a mean of 1 CO to 7 COs per cell. CO number can be further increased up to a mean of 12 COs per cell in these ph1b hybrids by treating the plants with Hoagland solution. More recently, it was shown that the major meiotic crossover gene ZIP4 on chromosome 5B ( TaZIP4-B2 ) within the 70 Mb deletion, was responsible for the restriction of homoeologous COs in wheat-wild relative hybrids, confirming the ph1b phenotype as a complete Tazip4-B2 deletion mutant ( Tazip4-B2 ph1b) . In this study, we have identified the particular Hoagland solution constituent responsible for the increased chiasma frequency in Tazip4-B2 ph1b mutant-rye hybrids and extended the analysis to Tazip4-B2 TILLING and CRISPR mutant- Ae variabilis hybrids. Chiasma frequency at meiotic metaphase I, in the absence of each Hoagland solution macronutrient (NH 4 H 2 PO 4 , KNO 3 , Ca (NO 3 )2·4H 2 O or Mg SO 4 ·7H 2 O) was analyzed. A significant decrease in homoeologous CO frequency was observed when the Mg 2+ ion was absent. A significant increase of homoeologous CO frequency was observed in all analyzed hybrids, when plants were irrigated with a 1 mM Mg 2+ solution. These observations suggest a role for magnesium supplementation in improving the success of genetic material introgression from wild relatives into wheat.

Frequency of reactivity for Porphyromonas gingivalis and Prevotella spp. in supra- and subgingival plaques, and periodontal clinical parameters according to subject age.

PubMed

Tanaka, Shoji; Murakami, Yukio; Ogiwara, Takako; Shoji, Masao; Seto, Kazuhito; Nagasaki, Masahumi; Fujisawa, Seiichiro

2002-08-01

The present study was conducted to assess the association between selected clinical parameters and the distribution of Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Prevotella nigrescens (Pn), and Prevotella melaninogenica (Pm) in supra- and subgingival plaque samples measured by an immunoslot blot assay (IBA) using their monoclonal antibodies. Plaque samples from 299 patients aged 6 to 69 randomly chosen from a group of dental outpatients were examined. Plaque index, gingival index, and probing depths were evaluated according to the criteria of positive (cell number > or = 10(6)) or negative (<106) reactivity to the 4 different monoclonal antibodies. An increase in probing depth in subjects exhibiting either a positive or negative reaction for the 4 test bacteria was associated with increasing age. Comparing bacteria-positive subgingival plaque samples to their corresponding bacteria-negative counterparts, we found an increased plaque index in children positive for any of the 4 bacteria; in addition, that for Pg and Pi was increased in subjects 40 to 49 years old. The gingival index increased with increasing amount of Pi and Pn, but not with Pg and Pm in those 20 to 29 years of age. The frequency of Pg reactivity in subgingival plaque was markedly enhanced in subjects older than 30 to 39 years of age, and was significantly higher than that in supragingival plaque. The frequency of Pi and Pn reactivity was significantly increased in adults aged 20 to 29 and plateaued at older ages. The frequency of Pm reactivity was relatively low and independent of subject age. The increase in probing depth with increasing age was not affected by the occurrence of periodontopathic bacteria. The high rate of occurrence of Pg, together with Pi and Pn, in subgingival plaque of the adult age groups was suggested to be associated with the high frequency of periodontal disease in the older age groups (above 30 to 49 years of age). The IBA appears to be useful for the efficient and rapid detection of periodontopathic bacteria.

Ambient air pollution and cancer in California Seventh-day Adventists.

PubMed

Mills, P K; Abbey, D; Beeson, W L; Petersen, F

1991-01-01

Cancer incidence and mortality in a cohort of 6,000 Seventh-day Adventist nonsmokers who were residents of California were monitored for a 6-y period, and relationships with long-term ambient concentrations of total suspended particulates (TSPs) and ozone (O3) were studied. Ambient concentrations were expressed as mean concentrations and exceedance frequencies, which are the number of hours during which concentrations exceeded specified cutoffs (e.g., federal and California air quality standards). Risk of malignant neoplasms in females increased concurrently with exceedance frequencies for all TSP cutoffs, except the lowest, and these increased risks were highly statistically significant. An increased risk of respiratory cancers was associated with only one cutoff of O3, and this result was of borderline significance. These results are presented in the context of setting standards for these two air pollutants.

The effects of nicotine exposure and PFC transection on the time-frequency distribution of VTA DA neurons' firing activities.

PubMed

Chen, Ting Y; Zhang, Die; Dragomir, Andrei; Akay, Yasemin; Akay, Metin

2011-05-01

We investigated the influence of nicotine exposure and prefrontal cortex (PFC) transections on ventral tegmental areas (VTA) dopamine (DA) neurons' firing activities using a time-frequency method based on the continuous wavelet transform (CWT). Extracellular single-unit neural activity was recorded from DA neurons in the VTA area of rats. One group had their PFC inputs to the VTA intact, while the other group had the inputs to VTA bilaterally transected immediate caudal to the PFC. We hypothesized that the systemic nicotine exposure will significantly change the energy distribution in the recorded neural activity. Additionally, we investigated whether the loss of inputs to the VTA caused by the PFC transection resulted in the cancellation of the nicotine' effect on the neurons' firing patterns. The time-frequency representations of VTA DA neurons firing activity were estimated from the reconstructed firing rate histogram. The energy contents were estimated from three frequency bands, which are known to encompass the significant modes of operation of DA neurons. Our results show that systemic nicotine exposure disrupts the energy distribution in PFC-intact rats. Particularly, there is a significant increase in energy contents of the 1-1.5 Hz frequency band. This corresponds to an observed increase in the firing rate of VTA DA neurons following nicotine exposure. Additionally, our results from PFC-transected rats show that there is no change in the energy distribution of the recordings after systemic nicotine exposure. These results indicate that the PFC plays an important role in affecting the activities of VTA DA neurons and that the CWT is a useful method for monitoring the changes in neural activity patterns in both time and frequency domains.

Pressure sensitivity of flow oscillations in postocclusive reactive skin hyperemia.

PubMed

Strucl, M; Peterec, D; Finderle, Z; Maver, J

1994-05-01

Skin blood flow was monitored using a laser-Doppler (LD) flowmeter in 21 healthy volunteers after an occlusion of the digital arteries. The peripheral vascular bed was exposed to occlusion ischemia of varying duration (1, 4, or 8 min) and to a change in digital arterial pressure produced by different positions of the arm above heart level to characterize the pattern of LD flow oscillations in postocclusive reactive hyperemia (PRH) and to elucidate the relevance of metabolic and myogenic mechanisms in governing its fundamental frequency. The descending part of the hyperemic flow was characterized by the appearance of conspicuous periodic oscillations with a mean fundamental frequency of 7.2 +/- 1.5 cycles/min (SD, n = 9), as assessed by a Fourier transform frequency analysis of 50-s sections of flow. The mean respiratory frequency during the periods of flow frequency analysis was 17.0 +/- 2.2 (SD, n = 9), and the PRH oscillations remained during apnea in all tested subjects. The area under the maximum flow curve increased significantly with prolongation of the occlusion (paired t test, P < 0.001; n = 9), but showed no dependence on the estimated blood pressure in the digital arteries, which suggests the predominant role of a metabolic component in this part of the PRH response. In contrast, the fundamental frequency of PRH oscillations exhibited a significant decrease with a reduction in the estimated digital arterial pressure (linear regression, b = 0.08, P < 0.001; n = 12), but did not change with the prolongation of arterial occlusion despite a significant increase in mean LD flow (paired t test, P < 0.001; n = 9).(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibitory effects of Enteromorpha linza polysaccharide on micronucleus of Allium sativum root cells.

PubMed

Zhang, Zhongshan; Wang, Xiaomei; Li, Jingfen; Liu, Chongbin; Zhang, Quanbin

2016-06-01

In this study, the antimutagenic function of the polysaccharide from Enteromorpha linza with the micronucleus test of Allium sativum root cells induced by sulfur dioxide and ultraviolet was studied. The concentration-effect relation of the two inducers was firstly evaluated. The results showed that an increase of genotoxicity damage was demonstrated and micronuclei frequency induced by sulfur dioxide and ultraviolet displayed dose dependent increases. All the doses of polysaccharide did affect the micronuclei frequency formation compared with the negative control. And also, the significant increase in inhibition rate of micronuclei frequency was observed with the increase of the dose of polysaccharide. It was showed maximum inhibition of micronuclei frequency cells (71.74% and 66.70%) at a concentration of 200g/mL in three experiments. The low molecular weight polysaccharide showed higher inhibition rate than raw polysaccharide at the higher concentration (50g/mL) in the absence of sulfur dioxide and ultraviolet. It was confirmed to be a good mutant inhibitor. Copyright © 2016 Elsevier B.V. All rights reserved.

Warming and increased precipitation frequency on the Colorado Plateau: Implications for biological soil crusts and soil processes

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

Zelikova TJ; Hosman DC; Grote EE

2011-03-21

Frequent hydration and drying of soils in arid systems can accelerate desert carbon and nitrogen mobilization due to respiration, microbial death, and release of intracellular solutes. Because desert microinvertebrates can mediate nutrient cycling, and the autotrophic components of crusts are known to be sensitive to rapid desiccation due to elevated temperatures after wetting events, we studied whether altered soil temperature and frequency of summer precipitation can also affect the composition of food web consumer functional groups. We conducted a two-year field study with experimentally-elevated temperature and frequency of summer precipitation in the Colorado Plateau desert, measuring the change in abundancemore » of nematodes, protozoans, and microarthropods. We hypothesized that microfauna would be more adversely affected by the combination of elevated temperature and frequency of summer precipitation than either effect alone, as found previously for phototrophic crust biota. Microfauna experienced normal seasonal fluctuations in abundance, but the effect of elevated temperature and frequency of summer precipitation was statistically non-significant for most microfaunal groups, except amoebae. The seasonal increase in abundance of amoebae was reduced with combined elevated temperature and increased frequency of summer precipitation compared to either treatment alone, but comparable with control (untreated) plots. Based on our findings, we suggest that desert soil microfauna are relatively more tolerant to increases in ambient temperature and frequency of summer precipitation than the autotrophic components of biological soil crust at the surface.« less

Few apparent short-term effects of elevated soil temperature and increased frequency of summer precipitation on the abundance and taxonomic diversity of desert soil micro- and meso-fauna

USGS Publications Warehouse

Darby, B.J.; Neher, D.A.; Housman, D.C.; Belnap, J.

2011-01-01

Frequent hydration and drying of soils in arid systems can accelerate desert carbon and nitrogen mobilization due to respiration, microbial death, and release of intracellular solutes. Because desert microinvertebrates can mediate nutrient cycling, and the autotrophic components of crusts are known to be sensitive to rapid desiccation due to elevated temperatures after wetting events, we studied whether altered soil temperature and frequency of summer precipitation can also affect the composition of food web consumer functional groups. We conducted a two-year field study with experimentally-elevated temperature and frequency of summer precipitation in the Colorado Plateau desert, measuring the change in abundance of nematodes, protozoans, and microarthropods. We hypothesized that microfauna would be more adversely affected by the combination of elevated temperature and frequency of summer precipitation than either effect alone, as found previously for phototrophic crust biota. Microfauna experienced normal seasonal fluctuations in abundance, but the effect of elevated temperature and frequency of summer precipitation was statistically non-significant for most microfaunal groups, except amoebae. The seasonal increase in abundance of amoebae was reduced with combined elevated temperature and increased frequency of summer precipitation compared to either treatment alone, but comparable with control (untreated) plots. Based on our findings, we suggest that desert soil microfauna are relatively more tolerant to increases in ambient temperature and frequency of summer precipitation than the autotrophic components of biological soil crust at the surface.

The relationship between gamma frequency and running speed differs for slow and fast gamma rhythms in freely behaving rats

PubMed Central

Zheng, Chenguang; Bieri, Kevin Wood; Trettel, Sean Gregory; Colgin, Laura Lee

2015-01-01

In hippocampal area CA1 of rats, the frequency of gamma activity has been shown to increase with running speed (Ahmed and Mehta, 2012). This finding suggests that different gamma frequencies simply allow for different timings of transitions across cell assemblies at varying running speeds, rather than serving unique functions. However, accumulating evidence supports the conclusion that slow (~25–55 Hz) and fast (~60–100 Hz) gamma are distinct network states with different functions. If slow and fast gamma constitute distinct network states, then it is possible that slow and fast gamma frequencies are differentially affected by running speed. In this study, we tested this hypothesis and found that slow and fast gamma frequencies change differently as a function of running speed in hippocampal areas CA1 and CA3, and in the superficial layers of the medial entorhinal cortex (MEC). Fast gamma frequencies increased with increasing running speed in all three areas. Slow gamma frequencies changed significantly less across different speeds. Furthermore, at high running speeds, CA3 firing rates were low, and MEC firing rates were high, suggesting that CA1 transitions from CA3 inputs to MEC inputs as running speed increases. These results support the hypothesis that slow and fast gamma reflect functionally distinct states in the hippocampal network, with fast gamma driven by MEC at high running speeds and slow gamma driven by CA3 at low running speeds. PMID:25601003

Cytotoxicity of diesel engine exhaust among the Chinese occupational population: a complement of cytokinesis-block micronucleus cytome.

PubMed

Zhang, Xiao; Xiao, Xinhua; Duan, Huawei; Gao, Feng; Li, Yuanyuan; Niu, Yong; Gao, Weimin; Wang, Haisheng; Yu, Shanfa; Zheng, Yuxin

2016-01-01

Diesel engine exhaust (DEE), a ubiquitous environmental pollutant, has been associated with adverse health effects. Revelation of cellular and molecular changes is critical for understanding environmental exposure-related diseases. Although the molecular-level effects of DEE exposure have been investigated, whether it is associated with aberrant changes at cellular level is largely unknown at the population level. In the present study, we measured urinary concentrations of 6 mono-hydroxylated PAHs (OH-PAHs) and cytotoxicity-related endpoints including apoptosis and necrosis frequencies, and nuclear division cytotoxicity index (NDCI) in peripheral blood lymphocytes (PBLs) of 79 DEE-exposed workers and 59 non-DEE-exposed workers. We found that DEE-exposed workers had significantly higher necrosis frequency and lower NDCI than did non-DEE-exposed workers (both p < 0.001). In all study subjects and nonsmoking workers, urinary summed OH-PAHs was associated with increased necrosis frequency and reduced NDCI. In nonsmoking workers, an interquartile range increase in urinary summed OH-PAHs was associated with 105.03% increase in necrosis frequency and 8.70% decrease in NDCI. Taking advantage of the previous measure of micronucleus frequency, we observed that micronucleus frequency was positively correlated with apoptosis and necrosis frequencies (r = 0.277, p = 0.047 and r = 0.452, p = 0.001, respectively) and negatively correlated with NDCI (r = -0.477, p < 0.001). In conclusion, our results suggested that DEE exposure was associated with increased necrosis frequency and further with reduced NDCI in PBLs, providing evidence of DEE exposure-induced cytotoxicity in humans.

The Power Spectrum of Ionic Nanopore Currents: The Role of Ion Correlations.

PubMed

Zorkot, Mira; Golestanian, Ramin; Bonthuis, Douwe Jan

2016-04-13

We calculate the power spectrum of electric-field-driven ion transport through nanometer-scale membrane pores using both linearized mean-field theory and Langevin dynamics simulations. Remarkably, the linearized mean-field theory predicts a plateau in the power spectral density at low frequency ω, which is confirmed by the simulations at low ion concentration. At high ion concentration, however, the power spectral density follows a power law that is reminiscent of the 1/ω(α) dependence found experimentally at low frequency. On the basis of simulations with and without ion-ion interactions, we attribute the low-frequency power-law dependence to ion-ion correlations. We show that neither a static surface charge density, nor an increased pore length, nor an increased ion valency have a significant effect on the shape of the power spectral density at low frequency.

Alcohol use, sexual relationship power, and unprotected sex among patrons in bars and taverns in rural areas of North West province, South Africa.

PubMed

Nkosi, Sebenzile; Rich, Eileen P; Morojele, Neo K

2014-11-01

We examined the relative importance of alcohol consumption and sexual relationship power (SRP) in predicting unprotected sex among 406 bar patrons in North West province, South Africa. We assessed participants' demographic characteristics, alcohol consumption, SRP, and number of unprotected sexual episodes in the past 6 months. In correlational analyses, alcohol consumption was significantly associated with frequency of unprotected sex for both males and females. SRP was significantly associated with frequency of unprotected sex for males and marginally associated for females. In multivariate regression analyses, alcohol consumption was significantly associated with frequency of unprotected sex for both males and females. SRP's association was marginally significant for females and not significant for males. Alcohol consumption is more strongly associated with unprotected sex than is SRP among bar patrons. Combination HIV prevention approaches to curb problem drinking and increase condom accessibility, and regular and effective use are needed in tavern settings. SRP needs further examination among tavern populations.

Big data integration shows Australian bush-fire frequency is increasing significantly.

PubMed

Dutta, Ritaban; Das, Aruneema; Aryal, Jagannath

2016-02-01

Increasing Australian bush-fire frequencies over the last decade has indicated a major climatic change in coming future. Understanding such climatic change for Australian bush-fire is limited and there is an urgent need of scientific research, which is capable enough to contribute to Australian society. Frequency of bush-fire carries information on spatial, temporal and climatic aspects of bush-fire events and provides contextual information to model various climate data for accurately predicting future bush-fire hot spots. In this study, we develop an ensemble method based on a two-layered machine learning model to establish relationship between fire incidence and climatic data. In a 336 week data trial, we demonstrate that the model provides highly accurate bush-fire incidence hot-spot estimation (91% global accuracy) from the weekly climatic surfaces. Our analysis also indicates that Australian weekly bush-fire frequencies increased by 40% over the last 5 years, particularly during summer months, implicating a serious climatic shift.

An experimental study of the effects of water repellant treatment on the acoustic properties of Kevlar

NASA Technical Reports Server (NTRS)

Smith, C. D.; Parrott, T. L.

1978-01-01

The treatment consisted of immersing samples of Kevlar in a solution of distilled water and Zepel. The samples were then drained, dried in a circulating over, and cured. Flow resistance tests showed approximately one percent decrease in flow resistance of the samples. Also there was a density increase of about three percent. It was found that the treatment caused a change in the texture of the samples. There were significant changes in the acoustic properties of the treated Kevlar over the frequency range 0.5 to 3.5 kHz. In general it was found that the propagation constant and characteristic impedance increased with increasing frequency. The real and imaginary components of the propagation constant for the treated Kevlar exhibited a decrease of 8 to 12 percent relative to that for the untreated Kevlar at the higher frequencies. The magnitude of the reactance component of the characteristic impedance decreased by about 40 percent at the higher frequencies.

Big data integration shows Australian bush-fire frequency is increasing significantly

PubMed Central

Dutta, Ritaban; Das, Aruneema; Aryal, Jagannath

2016-01-01

Increasing Australian bush-fire frequencies over the last decade has indicated a major climatic change in coming future. Understanding such climatic change for Australian bush-fire is limited and there is an urgent need of scientific research, which is capable enough to contribute to Australian society. Frequency of bush-fire carries information on spatial, temporal and climatic aspects of bush-fire events and provides contextual information to model various climate data for accurately predicting future bush-fire hot spots. In this study, we develop an ensemble method based on a two-layered machine learning model to establish relationship between fire incidence and climatic data. In a 336 week data trial, we demonstrate that the model provides highly accurate bush-fire incidence hot-spot estimation (91% global accuracy) from the weekly climatic surfaces. Our analysis also indicates that Australian weekly bush-fire frequencies increased by 40% over the last 5 years, particularly during summer months, implicating a serious climatic shift. PMID:26998312

Modeling seismic stimulation: Enhanced non-aqueous fluid extraction from saturated porous media under pore-pressure pulsing at low frequencies

NASA Astrophysics Data System (ADS)

Lo, Wei-Cheng; Sposito, Garrison; Huang, Yu-Han

2012-03-01

Seismic stimulation, the application of low-frequency stress-pulsing to the boundary of a porous medium containing water and a non-aqueous fluid to enhance the removal of the latter, shows great promise for both contaminated groundwater remediation and enhanced oil recovery, but theory to elucidate the underlying mechanisms lag significantly behind the progress achieved in experimental research. We address this conceptual lacuna by formulating a boundary-value problem to describe pore-pressure pulsing at seismic frequencies that is based on the continuum theory of poroelasticity for an elastic porous medium permeated by two immiscible fluids. An exact analytical solution is presented that is applied numerically using elasticity parameters and hydraulic data relevant to recent proof-of-principle laboratory experiments investigating the stimulation-induced mobilization of trichloroethene (TCE) in water flowing through a compressed sand core. The numerical results indicated that significant stimulation-induced increases of the TCE concentration in effluent can be expected from pore-pressure pulsing in the frequency range of 25-100 Hz, which is in good agreement with what was observed in the laboratory experiments. Sensitivity analysis of our numerical results revealed that the TCE concentration in the effluent increases with the porous medium framework compressibility and the pulsing pressure. Increasing compressibility also leads to an optimal stimulation response at lower frequencies, whereas changing the pulsing pressure does not affect the optimal stimulation frequency. Within the context of our model, the dominant physical cause for enhancement of non-aqueous fluid mobility by seismic stimulation is the dilatory motion of the porous medium in which the solid and fluid phases undergo opposite displacements, resulting in stress-induced changes of the pore volume.

Blunted day-night changes in luteinizing hormone pulse frequency in girls with obesity: the potential role of hyperandrogenemia.

PubMed

Collins, Jessicah S; Beller, Jennifer P; Burt Solorzano, Christine; Patrie, James T; Chang, R Jeffrey; Marshall, John C; McCartney, Christopher R

2014-08-01

Puberty is marked by sleep-associated changes in LH pulse frequency and amplitude. Early pubertal girls with obesity exhibit blunted day-to-night changes in LH secretion; whether this occurs in late pubertal obese girls is unknown. The objective of the study was to test two hypotheses: 1) blunted day-to-night changes in LH secretion occur in both early and late pubertal obese girls, and 2) such alterations are specifically associated with hyperandrogenemia. This was a cross-sectional analysis. The study was conducted at a clinical research center. Twenty-seven early pubertal, premenarcheal girls (12 of whom were obese) and 63 late pubertal (postmenarcheal) girls (27 of whom were obese) participated in the study. Blood samples were taken every 10 minutes from 7:00 pm to 7:00 am. Change in LH pulse frequency [LH interpulse interval (IPI)] from daytime hours (7:00 pm-11:00 pm, while awake) to nighttime hours (11:00 pm to 7:00 am, while generally asleep). Both nonobese and obese postmenarcheal girls demonstrated significant day-to-night decreases in LH pulse frequency (IPI increases of 33% and 16%, respectively), but day-to-night changes were blunted in obese girls (P = .004, obese vs nonobese). Day-to-night LH pulse frequency decreased significantly in postmenarcheal obese subjects with normal T concentrations (26% IPI increase) but not in those with hyperandrogenemia. Similar differences were evident for LH pulse amplitude. Nonobese and obese early pubertal girls exhibited nonsignificant differences in day-night LH pulse frequency (day to night IPI increase of 26% vs decrease of 1%, respectively). Day-to-night changes in LH pulse secretion are blunted in postmenarcheal obese adolescent girls. This phenomenon may in part reflect hyperandrogenemia.

Deeper Cochlear Implant Electrode Insertion Angle Improves Detection of Musical Sound Quality Deterioration Related to Bass Frequency Removal.

PubMed

Roy, Alexis T; Penninger, Richard T; Pearl, Monica S; Wuerfel, Waldemar; Jiradejvong, Patpong; Carver, Courtney; Buechner, Andreas; Limb, Charles J

2016-02-01

Cochlear implant (CI) electrode arrays typically do not reach the most apical regions of the cochlea that intrinsically encode low frequencies. This may contribute to diminished implant-mediated musical sound quality perception. The objective of this study was to assess the effect of varying degrees of apical cochlear stimulation (measured by angular insertion depth) on musical sound quality discrimination. Increased apical cochlear stimulation will improve low-frequency perception and musical sound quality discrimination. Standard (31.5 mm, n = 17) and medium (24 mm, n = 8) array Med-EL CI users, and normal hearing (NH) listeners (n = 16) participated. Imaging confirmed angular insertion depth. Participants completed a musical discrimination task in which they listened to a real-world musical stimulus (labeled reference) and provided sound quality ratings to versions of the reference, which included a hidden reference and test stimuli with increasing amounts of low-frequency removal. Scores for each CI users were calculated on the basis of how much their ratings differed from NH listeners for each stimulus version. Medium array and standard users had significantly different insertion depths (389.4 ± 64.5 and 583.9 ± 78.5 degrees, respectively; p <  .001). A significant Pearson's correlation was observed between angular insertion depth and the hidden reference scores (p < 0.05). CI users with greater apical stimulation made sound quality discriminations that more closely resembled those of NH controls for stimuli that contained low frequencies (< 200 Hz of information). These findings suggest that increased apical cochlear stimulation improves musical low-frequency perception, which may provide a more satisfactory music listening experience for CI users.

Role of dermatoglyphics as an indicator of precancerous and cancerous lesions of the oral cavity

PubMed Central

Gupta, Ambika; Karjodkar, Freny R

2013-01-01

Background: Oral squamous cell carcinoma (SCC) is one name that causes panic and holds an undeserved high ranking as a killer. Another important condition which has become a major public health issue in South East Asia is oral submucous fibrosis (OSF). Not all the people using tobacco suffer from these diseases. Genetic predisposition might explain such an individual variability that can be predicted by using various cytogenetic markers. However, these studies are far more costly and complicated. So, dermatoglyphics may be of immense clinical significance to segregate those individuals who are at an increased risk for developing these diseases. Aim: The present study was conducted to analyze the palmar dermatoglyphics in SCC and OSF and find a dermatoglyphic marker, if any. Study Design: Cross sectional study. Materials and Methods: 120 individuals were divided into four groups based upon their habits of tobacco/areca nut usage and presence of OSF/SCC. Dermatoglyphic patterns were recorded using standard ink method. Various patterns were analysed statistically in the four groups. Results and Conclusion: In SCC, there was an increase in frequency of arch and ulnar loop patterns on fingertips, decrease in frequency of simple whorl patterns on fingertips, decrease in frequency of palmar accessory triradii on right and left hands. Significant findings in OSF included an increase in frequency of arch and ulnar loop pattern, decrease in frequency of simple whorl patterns on fingertips, decrease in atd angle on right hand, decrease in frequency of palmar accessory triradii on right hand. The results revealed that the field of dermatoglyphics holds promising results for determining the genetic susceptibility of individuals to develop SCC and OSF. PMID:24403787

A Ground Observation Based Climatology and Forecasting of Winter Fog: Study over Ghaziabad, National Capital Region, India

NASA Astrophysics Data System (ADS)

Srivastava, S. K., Sr.; Sharma, D. A.; Sachdeva, K.

2015-12-01

Long term ground observations (1971-2010) have been analyzed over Ghaziabad city, National Capital Region to understand the characteristics of fog phenomenon and its relevance during winter months. We observed mean maximum fog occurrence during December (~23 days) followed by January (~21 days), November (~20 days), February (~14 days) and October (~11 days) respectively. A remarkable increase has been noticed in fog occurrence during October-to-February in last four decades. During 1971-80 to 2001-2010 the mean frequency of fog occurrence had increased by 205.5% in October month and 50.2% in November month. Similarly, mean frequency of fog occurrence increased by 51%, 97% and 119% during December, January and February respectively over the same period. We observed statistically significant increasing trend in fog occurrence from October-to-February during the study period at 95% confidence level. The magnitude of trend is 0.50, 0.47, 0.30, 0.39 and 0.37 for October, November, December, January and February, respectively. The magnitude of trend is highest in October but the occurrence frequency is highest in December. The forecast values obtained from ARIMA model indicates that the number of fog days is going to increase further during October-to-February in the forthcoming years. The data combined with knowledge of meteorology and topography suggested significant conclusions about increase in the fog events in the near future.

X-ray Variability Characteristics of the Narrow line SEYFERT 1 MKN 766 I: Energy Dependent Timing Properties

NASA Technical Reports Server (NTRS)

Markowitz, A.; Turner, T. J.; Papadakis, I.; Arevalo, P.; Reeves, J. N.; Miller, L.

2007-01-01

We present the energy-dependent power spectral density (PSD) and cross-spectral properties of Mkn 766 obtained from a six-revolution XMM-Newton observation in 2005. The resulting PSDs, which have highest temporal frequency resolution for an AGN PSD to date, show breaks which increase in temporal frequency as photon energy increases; break frequencies differ by an average of approx.0.4 in the log between the softest and hardest bands. The consistency of the 2001 and 2005 observations variability properties, namely PSD shapes and the linear rms-flux relation, suggests the 2005 observation is simply a low-flux extension of the 2001 observation. The coherence function is measured to be approx.0.6-0.9 at temporal frequencies below the PSD break, and is lower for relatively larger energy band separation; coherence also drops significantly towards zero above the PSD break frequency. Temporal frequency-dependent soft-to-hard time lags are detected in this object for the first time: lags increase towards longer time scales and as energy separation increases. Cross-spectral properties are the thus consistent with previous measurements for Mkn 766 (Vaughan & Fabian 2003) and other accreting black hole systems. The results are discussed in the context of several variability models, including those based on inwardly-propagating viscosity variations in the accretion disk.

Nanoscopic Dynamic Mechanical Properties of Intertubular and Peritubular Dentin

PubMed Central

Ryou, Heon; Romberg, Elaine; Pashley, David H.; Tay, Franklin R.; Arola, Dwayne

2011-01-01

An experimental evaluation of intertubular and peritubular dentin was performed using nanoindentation and Dynamic Mechanical Analysis (DMA). The objective of the investigation was to evaluate the differences in dynamic mechanical behavior of these two constituents and to assess if their response is frequency dependent. Specimens of hydrated coronal dentin were evaluated by DMA using single indents over a range in parametric conditions and using scanning probe microscopy. The complex (E*), storage (E’) and loss moduli (E”) of the intertubular and peritubular dentin were evaluated as a function of the dynamic loading frequency and static load in the fully hydrated condition. The mean complex E* (19.6 GPa) and storage E’ (19.2 GPa) moduli of the intertubular dentin were significantly lower than those quantities of peritubular dentin (E* = 31.1 GPa, p< 0.05; E’ = 30.3 GPa, p< 0.05). There was no significant influence of dynamic loading frequency on these measures. Though there was no significant difference in the loss modulus (E”) between the two materials (p> 0.05), both constituents exhibited a significant increase in E” with dynamic load frequency and reduction in the quasi-static component of indentation load. The largest difference in dynamic behavior of the two tissues was noted at small quasi-static indentation loads and the highest frequency. PMID:22340680

Oscillation of the human ankle joint in response to applied sinusoidal torque on the foot

PubMed Central

Agarwal, Gyan C.; Gottlieb, Gerald L.

1977-01-01

1. Low-frequency (3-30 Hz) oscillatory rotation of the ankle joint in plantarflexion—dorsiflexion was generated with a torque motor. Torque, rotation about the ankle and electromyograms (e.m.g.s) for the gastrocnemius—soleus and the anterior tibial muscles were recorded. 2. Fourier coefficients at each drive frequency were used to calculate the effective compliance (ratio of rotation and torque). The compliance has a sharp resonance when tonic, voluntary muscle activity is present. 3. The resonant frequency of compliance is between 3 and 8 Hz. The location of the resonant frequency and the magnitude of the compliance at resonance depend upon both the degree of tonic muscle activity and the amplitude of the driving torque. The resonant frequency increases with increasing tonic activity. 4. With tonic muscle activity, the compliance in the frequency range below resonance increases with increasing amplitudes of driving torque. 5. The e.m.g., when evoked by the rhythmic stretch, lags the start of stretching by between 50 and 70 msec. 6. When tonic muscle activity is present, the resonant frequency of the stretch reflex is between 5 and 6·5 Hz. 7. Following the start of driven oscillation at frequencies near resonance, slowly increasing amplitudes of angular rotation (to a limit) are observed. 8. Distortion (from the sinusoidal wave shape) of angular rotation is frequently observed with drive frequencies between 8 and 12 Hz during which there sometimes occur spontaneous recurrences of oscillation at the drive frequency. For the angular rotation, a significant portion of the power may be in subharmonic frequency components of the drive frequency when that frequency is between 8 and 12 Hz. 9. Self-sustaining oscillation (clonus) near the resonant frequency of the compliance is sometimes observed after the modulation signal to the motor is turned off. This is most often seen when the gastrocnemius—soleus muscles are fatigued. Clonus may be evoked by driven oscillation at any frequency. 10. The hypothesis that physiological tremor, which occurs between 8 and 12 Hz, is a consequence of stretch reflex servo properties seems to be at odds with the observations of resonance in the compliance and of self-generated clonus both occurring in the 5-8 Hz region. PMID:874886

Health resource utilization varies by comorbidities in children with epilepsy.

PubMed

Puka, Klajdi; Smith, Mary Lou; Moineddin, Rahim; Snead, O Carter; Widjaja, Elysa

2016-04-01

Comorbidities in adults with epilepsy have been shown to significantly increase health resource utilization (HRU). The current study aimed to determine whether a similar association exists among children with epilepsy in a universal health insurance system. Health administrative databases in Ontario, Canada were used to evaluate the frequency of neurologist visits, emergency department (ED) visits, and hospitalizations. We evaluated the association between HRU and comorbidities, including depression, anxiety, learning disability, attention deficit hyperactivity disorder (ADHD), and autistic spectrum disorder (ASD), adjusting for age, sex, residence, and socio-economic status. The frequency of neurology visits was increased by comorbid depression, ASD, and learning disability (adjusted relative risk [aRR]=1.29-2.07; p<.01). The frequency of ED visits was increased by all comorbidities (aRR=1.26-2.83; p<.0001). The frequency of hospitalizations was increased by comorbid depression, anxiety, ASD, and learning disability (aRR=1.77-7.20; p<.0001). Learning disability had the largest impact on HRU. For each additional comorbidity, the frequency of neurology visits, ED visits, and hospitalizations increased by 1.64 to 3.16 times (p<.0001). Among children with epilepsy, mental health and developmental comorbidities were associated with increased HRU, and different comorbidities influenced different types of HRU. In addition, we highlight the importance of identifying and managing these comorbidities, as they increased the risks of costly HRU such as ED visits and hospitalizations. Copyright © 2016 Elsevier Inc. All rights reserved.

Does increased urination frequency protect against bladder cancer?

PubMed

Silverman, Debra T; Alguacil, Juan; Rothman, Nathaniel; Real, Francisco X; Garcia-Closas, Montserrat; Cantor, Kenneth P; Malats, Nuria; Tardon, Adonina; Serra, Consol; Garcia-Closas, Reina; Carrato, Alfredo; Lloreta, Josep; Samanic, Claudine; Dosemeci, Mustafa; Kogevinas, Manolis

2008-10-01

Experimental studies suggest that increased urination frequency may reduce bladder cancer risk if carcinogens are present in the urine. Only 2 small studies of the effect of increased urination frequency on bladder cancer risk in humans have been conducted with conflicting results. Our purpose was to evaluate the effect of urination frequency on risk of bladder cancer in a large, multicenter case-control study. We analyzed data based on interviews conducted with 884 patients with newly diagnosed, bladder cancer and 996 controls from 1998 to 2001 in Spain. We observed a consistent, inverse trend in risk with increasing nighttime voiding frequency in both men (p = 0.0003) and women (p = 0.07); voiding at least 2 times per night was associated with a significant, 40-50% risk reduction. The protective effect of nocturia was apparent among study participants with low, moderate and high water consumption. The risk associated with cigarette smoking was reduced by nocturia. Compared with nonsmokers who did not urinate at night, current smokers who did not urinate at night had an OR of 7.0 (95% CI = 4.7-10.2), whereas those who voided at least twice per night had an OR of 3.3 (95% CI = 1.9-5.8) (p value for trend = 0.0005). Our findings suggest a strong protective effect of nocturia on bladder cancer risk, providing evidence in humans that bladder cancer risk is related to the contact time of the urothelium with carcinogens in urine. Increased urination frequency, coupled with possible dilution of the urine from increased water intake, may diminish the effect of urinary carcinogens on bladder cancer risk.

Thermoregulatory responses of rats exposed to 9. 3-GHz radio-frequency radiation

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

Frei, M.R.; Jauchem, J.R.; Heinmets, F.

1987-10-15

Ketamine-anesthetized Sprague-Dawley rats were exposed in H orientation to far-field 9.3-GHz continuous-wave (CW) and pulsed (2 microseconds 500 pps) radiofrequency radiation (RFR) at average power densities of 30 and 60 mW/sq. cm (whole-body average specific absorption rates of 9.3 and 18.6 W/kg, respectively). Irradiation was conducted to cyclicly increase colonic temperature from 38.5 to 39.5 C. Colonic, tympanic, and subcutaneous temperatures, ECG, blood pressure, and respiratory rate were continuously recorded during experimentation. At both power densities, the subcutaneous and tympanic temperature increases significantly exceeded the colonic temperature increase. At both exposure levels, heart rate increased significantly during irradiation and returnedmore » to baseline when exposure was discontinued. Blood pressure and respiratory rate did not significantly change during irradiation. There were no significant differences between the effects of CW and pulsed RFR exposure. The levels of subcutaneous heating and heart rate change were greater, and the times required to achieve and to recover from a 1 C colonic temperature increase were longer than in previous studies conducted at 2.8 GHz. Results of these studies indicate that the carrier frequency used during irradiation markedly affects the pattern of heat distribution and the physiological responses of RF-irradiated animals.« less

Nonlinear Interaction of Waves in Rotating Spherical Layers

NASA Astrophysics Data System (ADS)

Zhilenko, D.; Krivonosova, O.; Gritsevich, M.

2018-01-01

Flows of a viscous incompressible fluid in a spherical layer that are due to rotational oscillations of its inner boundary at two frequencies with respect to the state of rest are numerically studied. It is found that an increase in the amplitude of oscillations of the boundary at the higher frequency can result in a significant enhancement of the low-frequency mode in a flow near the outer boundary. The direction of propagation of the low-frequency wave changes from radial to meridional, whereas the high-frequency wave propagates in the radial direction in a limited inner region of the spherical layer. The role of the meridional circulation in the energy exchange between spaced waves is demonstrated.

How vulnerable is Texas’ freight infrastructure to extreme weather events? Final report.

DOT National Transportation Integrated Search

2017-03-01

The Texas Freight Mobility Plan forecasts significant increases in freight volumes across all transportation modes over the next three decades. An increased frequency of extreme weather events such as prolonged droughts and flash flooding is also exp...

Noise in the passenger cars of high-speed trains.

PubMed

Hong, Joo Young; Cha, Yongwon; Jeon, Jin Yong

2015-12-01

The aim of this study is to investigate the effects of both room acoustic conditions and spectral characteristics of noises on acoustic discomfort in a high-speed train's passenger car. Measurement of interior noises in a high-speed train was performed when the train was operating at speeds of 100 km/h and 300 km/h. Acoustic discomfort caused by interior noises was evaluated by paired comparison methods based on the variation of reverberation time (RT) in a passenger car and the spectral differences in interior noises. The effect of RT on acoustic discomfort was not significant, whereas acoustic discomfort significantly varied depending on spectral differences in noise. Acoustic discomfort increased with increment of the sound pressure level (SPL) ratio at high frequencies, and variation in high-frequency noise components were described using sharpness. Just noticeable differences of SPL with low- and high-frequency components were determined to be 3.7 and 2.9 dB, respectively. This indicates that subjects were more sensitive to differences in SPLs at the high-frequency range than differences at the low-frequency range. These results support that, for interior noises, reduction in SPLs at high frequencies would significantly contribute to improved acoustic quality in passenger cars of high-speed trains.

Influence of handrim wheelchair propulsion training in adolescent wheelchair users, a pilot study.

PubMed

Dysterheft, Jennifer L; Rice, Ian M; Rice, Laura A

2015-01-01

Ten full-time adolescent wheelchair users (ages 13-18) completed a total of three propulsion trials on carpet and tile surfaces, at a self-selected velocity, and on a concrete surface, at a controlled velocity. All trials were performed in their personal wheelchair with force and moment sensing wheels attached bilaterally. The first two trials on each surface were used as pre-intervention control trials. The third trial was performed after receiving training on proper propulsion technique. Peak resultant force, contact angle, stroke frequency, and velocity were recorded during all trials for primary analysis. Carpet and tile trials resulted in significant increases in contact angle and peak total force with decreased stroke frequency after training. During the velocity controlled trials on concrete, significant increases in contact angle occurred, as well as decreases in stroke frequency after training. Overall, the use of a training video and verbal feedback may help to improve short-term propulsion technique in adolescent wheelchair users and decrease the risk of developing upper limb pain and injury.

A rare functional cardioprotective APOC3 variant has risen in frequency in distinct population isolates

PubMed Central

Tachmazidou, Ioanna; Dedoussis, George; Southam, Lorraine; Farmaki, Aliki-Eleni; Ritchie, Graham R. S.; Xifara, Dionysia K.; Matchan, Angela; Hatzikotoulas, Konstantinos; Rayner, Nigel W.; Chen, Yuan; Pollin, Toni I.; O’Connell, Jeffrey R.; Yerges-Armstrong, Laura M.; Kiagiadaki, Chrysoula; Panoutsopoulou, Kalliope; Schwartzentruber, Jeremy; Moutsianas, Loukas; Tsafantakis, Emmanouil; Tyler-Smith, Chris; McVean, Gil; Xue, Yali; Zeggini, Eleftheria

2013-01-01

Isolated populations can empower the identification of rare variation associated with complex traits through next generation association studies, but the generalizability of such findings remains unknown. Here we genotype 1,267 individuals from a Greek population isolate on the Illumina HumanExome Beadchip, in search of functional coding variants associated with lipids traits. We find genome-wide significant evidence for association between R19X, a functional variant in APOC3, with increased high-density lipoprotein and decreased triglycerides levels. Approximately 3.8% of individuals are heterozygous for this cardioprotective variant, which was previously thought to be private to the Amish founder population. R19X is rare (<0.05% frequency) in outbred European populations. The increased frequency of R19X enables discovery of this lipid traits signal at genome-wide significance in a small sample size. This work exemplifies the value of isolated populations in successfully detecting transferable rare variant associations of high medical relevance. PMID:24343240

A rare functional cardioprotective APOC3 variant has risen in frequency in distinct population isolates.

PubMed

Tachmazidou, Ioanna; Dedoussis, George; Southam, Lorraine; Farmaki, Aliki-Eleni; Ritchie, Graham R S; Xifara, Dionysia K; Matchan, Angela; Hatzikotoulas, Konstantinos; Rayner, Nigel W; Chen, Yuan; Pollin, Toni I; O'Connell, Jeffrey R; Yerges-Armstrong, Laura M; Kiagiadaki, Chrysoula; Panoutsopoulou, Kalliope; Schwartzentruber, Jeremy; Moutsianas, Loukas; Tsafantakis, Emmanouil; Tyler-Smith, Chris; McVean, Gil; Xue, Yali; Zeggini, Eleftheria

2013-01-01

Isolated populations can empower the identification of rare variation associated with complex traits through next generation association studies, but the generalizability of such findings remains unknown. Here we genotype 1,267 individuals from a Greek population isolate on the Illumina HumanExome Beadchip, in search of functional coding variants associated with lipids traits. We find genome-wide significant evidence for association between R19X, a functional variant in APOC3, with increased high-density lipoprotein and decreased triglycerides levels. Approximately 3.8% of individuals are heterozygous for this cardioprotective variant, which was previously thought to be private to the Amish founder population. R19X is rare (<0.05% frequency) in outbred European populations. The increased frequency of R19X enables discovery of this lipid traits signal at genome-wide significance in a small sample size. This work exemplifies the value of isolated populations in successfully detecting transferable rare variant associations of high medical relevance.

Ambient noise and temporal patterns of boat activity in the US Virgin Islands National Park.

PubMed

Kaplan, Maxwell B; Mooney, T Aran

2015-09-15

Human activity is contributing increasing noise to marine ecosystems. Recent studies have examined the effects of boat noise on marine fishes, but there is limited understanding of the prevalence of this type of sound source. This investigation tracks vessel noise on three reefs in the US Virgin Islands National Park over four months in 2013. Ambient noise levels ranged from 106 to 129dBrms re 1μPa (100Hz-20kHz). Boat noise occurred in 6-12% of samples. In the presence of boat noise, ambient noise in a low-frequency band (100-1000Hz) increased by >7dB above baseline levels and sound levels were significantly higher. The frequency with the most acoustic energy shifted to a significantly lower frequency when boat noise was present during the day. These results indicate the abundance of boat noise and its overlap with reef organism sound production, raising concern for the communication abilities of these animals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Regional changes in extreme monsoon rainfall deficit and excess in India

NASA Astrophysics Data System (ADS)

Pal, Indrani; Al-Tabbaa, Abir

2010-04-01

With increasing concerns about climate change, the need to understand the nature and variability of monsoon climatic conditions and to evaluate possible future changes becomes increasingly important. This paper deals with the changes in frequency and magnitudes of extreme monsoon rainfall deficiency and excess in India from 1871 to 2005. Five regions across India comprising variable climates were selected for the study. Apart from changes in individual regions, changing tendencies in extreme monsoon rainfall deficit and excess were also determined for the Indian region as a whole. The trends and their significance were assessed using non-parametric Mann-Kendall technique. The results show that intra-region variability for extreme monsoon seasonal precipitation is large and mostly exhibited a negative tendency leading to increasing frequency and magnitude of monsoon rainfall deficit and decreasing frequency and magnitude of monsoon rainfall excess.

Chaotic mixing in microchannels via low frequency switching transverse electroosmotic flow generated on integrated microelectrodes.

PubMed

Song, Hongjun; Cai, Ziliang; Noh, Hongseok Moses; Bennett, Dawn J

2010-03-21

In this paper we present a numerical and experimental investigation of a chaotic mixer in a microchannel via low frequency switching transverse electroosmotic flow. By applying a low frequency, square-wave electric field to a pair of parallel electrodes placed at the bottom of the channel, a complex 3D spatial and time-dependence flow was generated to stretch and fold the fluid. This significantly enhanced the mixing effect. The mixing mechanism was first investigated by numerical and experimental analysis. The effects of operational parameters such as flow rate, frequency, and amplitude of the applied voltage have also been investigated. It is found that the best mixing performance is achieved when the frequency is around 1 Hz, and the required mixing length is about 1.5 mm for the case of applied electric potential 5 V peak-to-peak and flow rate 75 microL h(-1). The mixing performance was significantly enhanced when the applied electric potential increased or the flow rate of fluids decreased.

Changes in whistle structure of resident bottlenose dolphins in relation to underwater noise and boat traffic.

PubMed

Gospić, Nikolina Rako; Picciulin, Marta

2016-04-15

The habitat of the resident bottlenose dolphins (Tursiops truncatus) of the Cres-Lošinj archipelago overlaps with routes of intense boat traffic. Within these waters, Sea Ambient Noise (SAN) was sampled across ten acoustic stations between 2007 and 2009. Data on boat presence was concurrently collected and when dolphins were sighted group behaviour was also recorded. Acoustic recordings were analysed for 1/3 octave bands. Samples containing dolphin whistles were analysed and compared with boat presence and SAN levels. Results indicate that dolphins whistle at higher frequencies in conditions of elevated low frequency noise. Conversely, they reduce maximum, delta and start frequencies and frequency modulations when noise levels increase significantly across higher frequencies. The study shows that high levels of SAN causes significant changes in the acoustic structure of dolphin whistles. Additionally, changes in whistle parameters, in the presence of boats, appear to be related to the behavioural state of the dolphin group. Copyright © 2016 Elsevier Ltd. All rights reserved.

Blue whales respond to simulated mid-frequency military sonar.

PubMed

Goldbogen, Jeremy A; Southall, Brandon L; DeRuiter, Stacy L; Calambokidis, John; Friedlaender, Ari S; Hazen, Elliott L; Falcone, Erin A; Schorr, Gregory S; Douglas, Annie; Moretti, David J; Kyburg, Chris; McKenna, Megan F; Tyack, Peter L

2013-08-22

Mid-frequency military (1-10 kHz) sonars have been associated with lethal mass strandings of deep-diving toothed whales, but the effects on endangered baleen whale species are virtually unknown. Here, we used controlled exposure experiments with simulated military sonar and other mid-frequency sounds to measure behavioural responses of tagged blue whales (Balaenoptera musculus) in feeding areas within the Southern California Bight. Despite using source levels orders of magnitude below some operational military systems, our results demonstrate that mid-frequency sound can significantly affect blue whale behaviour, especially during deep feeding modes. When a response occurred, behavioural changes varied widely from cessation of deep feeding to increased swimming speed and directed travel away from the sound source. The variability of these behavioural responses was largely influenced by a complex interaction of behavioural state, the type of mid-frequency sound and received sound level. Sonar-induced disruption of feeding and displacement from high-quality prey patches could have significant and previously undocumented impacts on baleen whale foraging ecology, individual fitness and population health.

BAX and tumor suppressor TRP53 are important in regulating mutagenesis in spermatogenic cells in mice.

PubMed

Xu, Guogang; Vogel, Kristine S; McMahan, C Alex; Herbert, Damon C; Walter, Christi A

2010-12-01

During the first wave of spermatogenesis, and in response to ionizing radiation, elevated mutant frequencies are reduced to a low level by unidentified mechanisms. Apoptosis is occurring in the same time frame that the mutant frequency declines. We examined the role of apoptosis in regulating mutant frequency during spermatogenesis. Apoptosis and mutant frequencies were determined in spermatogenic cells obtained from Bax-null or Trp53-null mice. The results showed that spermatogenic lineage apoptosis was markedly decreased in Bax-null mice and was accompanied by a significantly increased spontaneous mutant frequency in seminiferous tubule cells compared to that of wild-type mice. Apoptosis profiles in the seminiferous tubules for Trp53-null were similar to control mice. Spontaneous mutant frequencies in pachytene spermatocytes and in round spermatids from Trp53-null mice were not significantly different from those of wild-type mice. However, epididymal spermatozoa from Trp53-null mice displayed a greater spontaneous mutant frequency compared to that from wild-type mice. A greater proportion of spontaneous transversions and a greater proportion of insertions/deletions 15 days after ionizing radiation were observed in Trp53-null mice compared to wild-type mice. Base excision repair activity in mixed germ cell nuclear extracts prepared from Trp53-null mice was significantly lower than that for wild-type controls. These data indicate that BAX-mediated apoptosis plays a significant role in regulating spontaneous mutagenesis in seminiferous tubule cells obtained from neonatal mice, whereas tumor suppressor TRP53 plays a significant role in regulating spontaneous mutagenesis between postmeiotic round spermatid and epididymal spermatozoon stages of spermiogenesis.

Task-induced frequency modulation features for brain-computer interfacing

NASA Astrophysics Data System (ADS)

Jayaram, Vinay; Hohmann, Matthias; Just, Jennifer; Schölkopf, Bernhard; Grosse-Wentrup, Moritz

2017-10-01

Objective. Task-induced amplitude modulation of neural oscillations is routinely used in brain-computer interfaces (BCIs) for decoding subjects’ intents, and underlies some of the most robust and common methods in the field, such as common spatial patterns and Riemannian geometry. While there has been some interest in phase-related features for classification, both techniques usually presuppose that the frequencies of neural oscillations remain stable across various tasks. We investigate here whether features based on task-induced modulation of the frequency of neural oscillations enable decoding of subjects’ intents with an accuracy comparable to task-induced amplitude modulation. Approach. We compare cross-validated classification accuracies using the amplitude and frequency modulated features, as well as a joint feature space, across subjects in various paradigms and pre-processing conditions. We show results with a motor imagery task, a cognitive task, and also preliminary results in patients with amyotrophic lateral sclerosis (ALS), as well as using common spatial patterns and Laplacian filtering. Main results. The frequency features alone do not significantly out-perform traditional amplitude modulation features, and in some cases perform significantly worse. However, across both tasks and pre-processing in healthy subjects the joint space significantly out-performs either the frequency or amplitude features alone. This result only does not hold for ALS patients, for whom the dataset is of insufficient size to draw any statistically significant conclusions. Significance. Task-induced frequency modulation is robust and straight forward to compute, and increases performance when added to standard amplitude modulation features across paradigms. This allows more information to be extracted from the EEG signal cheaply and can be used throughout the field of BCIs.

Elevated frequencies of micronuclei in pregnant women with type 1 diabetes mellitus and in their newborns.

PubMed

Witczak, Monika; Ferenc, Tomasz; Gulczyńska, Ewa; Nowakowska, Dorota; Łopaczyńska, Dobrosława; Wilczyński, Jan

2014-03-15

Pregestational diabetes mellitus (type 1 and type 2) affects about 1% of the obstetric population. In diabetes, persistent hyperglycemia can be a source of DNA damage via overproduction of reactive oxygen species (ROS). Using the cytokinesis-block micronucleus (CBMN) test, we measured the frequencies of micronuclei (MN) per 1000 binucleated (BN) cells in pregnant women (mothers) with type 1 diabetes mellitus (T1DM) and in their newborns. Peripheral blood lymphocytes were collected from 17 pregnant women with T1DM and cord-blood lymphocytes from their 17 newborns. The control group included 40 pregnant women (mothers) without diabetes mellitus (DM) and their 40 newborns. In the group of pregnant women with T1DM, the mean number of MN per 1000 BN cells was 2.35 (±1.07), significantly (p<0.001) higher than in the control group of pregnant women (0.86±0.90). The frequency value in the group of newborns of T1DM mothers was 1.42 (±0.60), significantly (p<0.05) higher than in the corresponding control group (0.67±0.79). The value in the group of mothers with T1DM was significantly (p<0.05) higher than in their newborns. Comparing mothers without DM with their newborns, no significant frequency differences were observed. No significant correlations were observed between MN frequencies in mothers with T1DM and either the frequencies in their newborns, the duration of diabetes, or HbA1C levels. Our results indicate that T1DM is accompanied by increased frequencies of MN in pregnant women and their newborns. Copyright © 2014 Elsevier B.V. All rights reserved.

Assessing complexity of skin blood flow oscillations in response to locally applied heating and pressure in rats: Implications for pressure ulcer risk

NASA Astrophysics Data System (ADS)

Liao, Fuyuan; O'Brien, William D.; Jan, Yih-Kuen

2013-10-01

The objective of this study was to investigate the effects of local heating on the complexity of skin blood flow oscillations (BFO) under prolonged surface pressure in rats. Eleven Sprague-Dawley rats were studied: 7 rats underwent surface pressure with local heating (△t=10 °C) and 4 rats underwent pressure without heating. A pressure of 700 mmHg was applied to the right trochanter area of rats for 3 h. Skin blood flow was measured using laser Doppler flowmetry. The loading period was divided into nonoverlapping 30 min epochs. For each epoch, multifractal detrended fluctuation analysis (MDFA) was utilized to compute DFA coefficients and complexity of endothelial related metabolic, neurogenic, and myogenic frequencies of BFO. The results showed that under surface pressure, local heating led to a significant decrease in DFA coefficients of myogenic frequency during the initial epoch of loading period, a sustained decrease in complexity of myogenic frequency, and a significantly higher degree of complexity of metabolic frequency during the later phase of loading period. Surrogate tests showed that the reduction in complexity of myogenic frequency was associated with a loss of nonlinearity whereas increased complexity of metabolic frequency was associated with enhanced nonlinearity. Our results indicate that increased metabolic activity and decreased myogenic response due to local heating manifest themselves not only in magnitudes of metabolic and myogenic frequencies but also in their structural complexity. This study demonstrates the feasibility of using complexity analysis of BFO to monitor the ischemic status of weight-bearing skin and risk of pressure ulcers.

Directions for Space-Based Low-Frequency Radio Astronomy 2. Telescopes

NASA Astrophysics Data System (ADS)

Basart, J. P.; Burns, J. O.; Dennison, B. K.; Weiler, K. W.; Kassim, N. E.; Castillo, S. P.; McCune, B. M.

Astronomical studies of celestial sources at low radio frequencies (0.3 to 30 MHz) lag far behind the investigations of celestial sources at high radio frequencies. In a companion paper [Basart et al., this issue] we discussed the need for low-frequency investigations, and in this paper we discuss the telescopes required to make the observations. Radio telescopes for use in the low-frequency range can be built principally from ``off-the-shelf'' components. For relatively little cost for a space mission, great strides can be made in deploying arrays of antennas and receivers in space that would produce data contributing significantly to our understanding of galaxies and galactic nebulae. In this paper we discuss an evolutionary sequence of telescopes, antenna systems, receivers, and (u,v) plane coverage. The telescopes are space-based because of the disruptive aspects of the Earth's ionosphere on low-frequency celestial signals traveling to the Earth's surface. Orbiting antennas consisting of array elements deposited on a Kevlar balloon have strong advantages of nearly identical multiple beams over 4π steradians and few mechanical aspects in deployment and operation. The relatively narrow beam width of these antennas can significantly help reduce the ``confusion'' problem. The evolutionary sequence of telescopes starts with an Earth-orbiting spectrometer to measure the low-frequency radio environment in space, proceeds to a two-element interferometer, then to an orbiting array, and ends with a telescope on the lunar farside. The sequence is in the order of increasing capability which is also the order of increasing complexity and cost. All the missions can be accomplished with current technology.

Low-frequency stimulation in anterior nucleus of thalamus alleviates kainate-induced chronic epilepsy and modulates the hippocampal EEG rhythm.

PubMed

Wang, Yi; Liang, Jiao; Xu, Cenglin; Wang, Ying; Kuang, Yifang; Xu, Zhenghao; Guo, Yi; Wang, Shuang; Gao, Feng; Chen, Zhong

2016-02-01

High-frequency stimulation (HFS) of the anterior nucleus of thalamus (ANT) is a new and alternative option for the treatment of intractable epilepsy. However, the responder rate is relatively low. The present study was designed to determine the effect of low-frequency stimulation (LFS) in ANT on chronic spontaneous recurrent seizures and related pathological pattern in intra-hippocampal kainate mouse model. We found that LFS (1 Hz, 100 μs, 300 μA), but not HFS (100 Hz, 100 μs, 30 μA), in bilateral ANT significantly decreased the frequency of spontaneous recurrent seizures, either non-convulsive focal seizures or tonic-clonic generalized seizures. The anti-epileptic effect persisted for one week after LFS cessation, which manifested as a long-term inhibition of the frequency of seizures with short (20-60 s) and intermediate duration (60-120 s). Meanwhile, LFS decreased the frequency of high-frequency oscillations (HFOs) and interictal spikes, two indicators of seizure severity, whereas HFS increased the HFO frequency. Furthermore, LFS decreased the power of the delta band and increased the power of the gamma band of hippocampal background EEG. In addition, LFS, but not HFS, improved the performance of chronic epileptic mice in objection-location task, novel objection recognition and freezing test. These results provide the first evidence that LFS in ANT alleviates kainate-induced chronic epilepsy and cognitive impairment, which may be related to the modulation of the hippocampal EEG rhythm. This may be of great therapeutic significance for clinical treatment of epilepsy with deep brain stimulation. Copyright © 2015 Elsevier Inc. All rights reserved.

The microbial changes in subgingival plaques of orthodontic patients: a systematic review and meta-analysis of clinical trials.

PubMed

Guo, Runzhi; Lin, Yifan; Zheng, Yunfei; Li, Weiran

2017-06-02

Orthodontic treatment was found to have an impact on the quantity and constitution of subgingival microbiota. However, contradictory findings regarding the effects of fixed appliances on microbial changes were reported. The aim of this systematic review was to investigate the microbial changes in subgingival plaques of orthodontic patients. The PubMed, Cochrane Library, and EMBASE databases were searched up to November 20, 2016. Longitudinal studies observing microbial changes in subgingival plaques at different time points of orthodontic treatment are included. The methodological quality of the included studies was assessed by Methodological index for non-randomized studies (MINORS). The studies that reported the frequency of subgingival periodontopathogens were used for quantitative analysis. Other studies were analysed qualitatively to describe the microbial changes during orthodontic treatment. Thirteen studies were selected, including two controlled clinical trials, three cohort studies and eight self-controlled studies. Four periodontopathogens, including Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi) and Tannerella forsythia (Tf), were analysed. Following orthodontic appliance placement, the frequencies of Pg and Aa showed no significant change (P = 0.97 and P = 0.77), whereas the frequency of Tf significantly increased (P < 0.01) during short-term observation (0-3 months). The frequency of Pi showed a tooth-specific difference, as it presented no significant difference (P = 0.25) at the site of the first molar but was significantly increased (P = 0.01) at the incisor. During long-term observation (> = 6 months), two studies reported that the levels of subgingival periodontopathogens exhibited a transient increase but decreased to the pretreatment levels afterwards. After removal of the orthodontic appliance, the four periodontopathogens showed no significant difference compared with before removal. The levels of subgingival pathogens presented temporary increases after orthodontic appliance placement, and appeared to return to pretreatment levels several months later. This indicates that orthodontic treatment might not permanently induce periodontal disease by affecting the level of subgingival periodontal pathogen levels. Further studies of high methodological quality are required to provide more reliable evidence regarding this issue.

Ambulatory Voice Biofeedback: Relative Frequency and Summary Feedback Effects on Performance and Retention of Reduced Vocal Intensity in the Daily Lives of Participants with Normal Voices

ERIC Educational Resources Information Center

Van Stan, Jarrad H.; Mehta, Daryush D.; Sternad, Dagmar; Petit, Robert; Hillman, Robert E.

2017-01-01

Purpose: Ambulatory voice biofeedback has the potential to significantly improve voice therapy effectiveness by targeting carryover of desired behaviors outside the therapy session (i.e., retention). This study applies motor learning concepts (reduced frequency and delayed, summary feedback) that demonstrate increased retention to ambulatory voice…

Role of glutamate and substance P in the amphibian respiratory network during development

PubMed Central

Chen, Anna K.; Hedrick, Michael S.

2008-01-01

This study tested the hypothesis that glutamatergic ionotropic (AMPA/kainate) receptors and neurokinin receptors (NKR) are important in the regulation of respiratory motor output during development in the bullfrog. The roles of these receptors were studied with in vitro brainstem preparations from pre-metamorphic tadpoles and post-metamorphic frogs. Brainstems were superfused with an artificial cerebrospinal fluid at 20–22°C containing CNQX, a selective non-NMDA antagonist, or with substance P (SP), an agonist of NKR. Blockade of glutamate receptors with CNQX in both groups caused a reduction of lung burst frequency that was reversibly abolished at 5 μM (P<0.01). CNQX, but not SP, application produced a significant increase (P<0.05) in gill and buccal frequency in tadpoles and frogs, respectively. SP caused a significant increase (P<0.05) in lung burst frequency at 5 μM in both groups. These results suggest that glutamatergic activation of AMPA/kainate receptors is necessary for generation of lung burst activity and that SP is an excitatory neurotransmitter for lung burst frequency generation. Both glutamate and SP provide excitatory input for lung burst generation throughout the aquatic to terrestrial developmental transition in bullfrogs. PMID:18450524

Role of glutamate and substance P in the amphibian respiratory network during development.

PubMed

Chen, Anna K; Hedrick, Michael S

2008-06-30

This study tested the hypothesis that glutamatergic ionotropic (AMPA/kainate) receptors and neurokinin receptors (NKR) are important in the regulation of respiratory motor output during development in the bullfrog. The roles of these receptors were studied with in vitro brainstem preparations from pre-metamorphic tadpoles and post-metamorphic frogs. Brainstems were superfused with an artificial cerebrospinal fluid at 20-22 degrees C containing CNQX, a selective non-NMDA antagonist, or with substance P (SP), an agonist of NKR. Blockade of glutamate receptors with CNQX in both groups caused a reduction of lung burst frequency that was reversibly abolished at 5 microM (P<0.01). CNQX, but not SP, application produced a significant increase (P<0.05) in gill and buccal frequency in tadpoles and frogs, respectively. SP caused a significant increase (P<0.05) in lung burst frequency at 5 microM in both groups. These results suggest that glutamatergic activation of AMPA/kainate receptors is necessary for generation of lung burst activity and that SP is an excitatory neurotransmitter for lung burst frequency generation. Both glutamate and SP provide excitatory input for lung burst generation throughout the aquatic to terrestrial developmental transition in bullfrogs.

Continuous exposure to low-frequency noise and carbon disulfide: Combined effects on hearing.

PubMed

Venet, Thomas; Carreres-Pons, Maria; Chalansonnet, Monique; Thomas, Aurélie; Merlen, Lise; Nunge, Hervé; Bonfanti, Elodie; Cosnier, Frédéric; Llorens, Jordi; Campo, Pierre

2017-09-01

Carbon disulfide (CS 2 ) is used in industry; it has been shown to have neurotoxic effects, causing central and distal axonopathies.However, it is not considered cochleotoxic as it does not affect hair cells in the organ of Corti, and the only auditory effects reported in the literature were confined to the low-frequency region. No reports on the effects of combined exposure to low-frequency noise and CS 2 have been published to date. This article focuses on the effects on rat hearing of combined exposure to noise with increasing concentrations of CS 2 (0, 63,250, and 500ppm, 6h per day, 5 days per week, for 4 weeks). The noise used was a low-frequency noise ranging from 0.5 to 2kHz at an intensity of 106dB SPL. Auditory function was tested using distortion product oto-acoustic emissions, which mainly reflects the cochlear performances. Exposure to noise alone caused an auditory deficit in a frequency area ranging from 3.6 to 6 kHz. The damaged area was approximately one octave (6kHz) above the highest frequency of the exposure noise (2.8kHz); it was a little wider than expected based on the noise spectrum.Consequently, since maximum hearing sensitivity is located around 8kHz in rats, low-frequency noise exposure can affect the cochlear regions detecting mid-range frequencies. Co-exposure to CS 2 (250-ppm and over) and noise increased the extent of the damaged frequency window since a significant auditory deficit was measured at 9.6kHz in these conditions.Moreover, the significance at 9.6kHz increased with the solvent concentrations. Histological data showed that neither hair cells nor ganglion cells were damaged by CS 2 . This discrepancy between functional and histological data is discussed. Like most aromatic solvents, carbon disulfide should be considered as a key parameter in hearing conservation régulations. Copyright © 2017 Elsevier B.V. All rights reserved.

The Significance of Shifts in Precipitation Patterns: Modelling the Impacts of Climate Change and Glacier Retreat on Extreme Flood Events in Denali National Park, Alaska

PubMed Central

Crossman, Jill; Futter, Martyn N.; Whitehead, Paul G.

2013-01-01

In glacier-fed systems climate change may have various effects over a range of time scales, including increasing river discharge, flood frequency and magnitude. This study uses a combination of empirical monitoring and modelling to project the impacts of climate change on the glacial-fed Middle Fork Toklat River, Denali National Park, Alaska. We use a regional calibration of the model HBV to account for a paucity of long term observed flow data, validating a local application using glacial mass balance data and summer flow records. Two Global Climate Models (HADCM3 and CGCM2) and two IPCC scenarios (A2 and B2) are used to ascertain potential changes in meteorological conditions, river discharge, flood frequency and flood magnitude. Using remote sensing methods this study refines existing estimates of glacial recession rates, finding that since 2000, rates have increased from 24m per year to 68.5m per year, with associated increases in ablation zone ice loss. GCM projections indicate that over the 21st century these rates will increase still further, most extensively under the CGCM2 model, and A2 scenarios. Due to greater winter precipitation and ice and snow accumulation, glaciers release increasing meltwater quantities throughout the 21st century. Despite increases in glacial melt, results indicate that it is predominantly precipitation that affects river discharge. Three of the four IPCC scenarios project increases in flood frequency and magnitude, events which were primarily associated with changing precipitation patterns, rather than extreme temperature increases or meltwater release. Results suggest that although increasing temperatures will significantly increase glacial melt and winter baseflow, meltwater alone does not pose a significant flood hazard to the Toklat River catchment. Projected changes in precipitation are the primary concern, both through changing snow volumes available for melt, and more directly through increasing catchment runoff. PMID:24023925

The significance of shifts in precipitation patterns: modelling the impacts of climate change and glacier retreat on extreme flood events in Denali National Park, Alaska.

PubMed

Crossman, Jill; Futter, Martyn N; Whitehead, Paul G

2013-01-01

In glacier-fed systems climate change may have various effects over a range of time scales, including increasing river discharge, flood frequency and magnitude. This study uses a combination of empirical monitoring and modelling to project the impacts of climate change on the glacial-fed Middle Fork Toklat River, Denali National Park, Alaska. We use a regional calibration of the model HBV to account for a paucity of long term observed flow data, validating a local application using glacial mass balance data and summer flow records. Two Global Climate Models (HADCM3 and CGCM2) and two IPCC scenarios (A2 and B2) are used to ascertain potential changes in meteorological conditions, river discharge, flood frequency and flood magnitude. Using remote sensing methods this study refines existing estimates of glacial recession rates, finding that since 2000, rates have increased from 24 m per year to 68.5m per year, with associated increases in ablation zone ice loss. GCM projections indicate that over the 21(st) century these rates will increase still further, most extensively under the CGCM2 model, and A2 scenarios. Due to greater winter precipitation and ice and snow accumulation, glaciers release increasing meltwater quantities throughout the 21(st) century. Despite increases in glacial melt, results indicate that it is predominantly precipitation that affects river discharge. Three of the four IPCC scenarios project increases in flood frequency and magnitude, events which were primarily associated with changing precipitation patterns, rather than extreme temperature increases or meltwater release. Results suggest that although increasing temperatures will significantly increase glacial melt and winter baseflow, meltwater alone does not pose a significant flood hazard to the Toklat River catchment. Projected changes in precipitation are the primary concern, both through changing snow volumes available for melt, and more directly through increasing catchment runoff.

Evaluation of respiratory parameters in rats and rabbits exposed to methyl iodide.

PubMed

DeLorme, Michael P; Himmelstein, Mathew W; Kemper, Raymond A; Kegelman, Thomas A; Gargas, Michael L; Kinzell, John H

2009-05-01

Laboratory animals exposed to methyl iodide (MeI) have previously demonstrated lesions of the olfactory epithelium that were associated with local metabolism in the nasal tissues. Interactions of MeI in the nasal passage may, therefore, alter systemic toxicokinetics. The current study used unrestrained plethysmographs to determine the MeI effect on the breathing frequency and minute volume (MV) in rats and rabbits. Groups of 4 rats each were exposed to 0, 25, or 100 ppm and groups of 4 rabbits each were exposed to 0 and 20 ppm MeI for 6 h. Breathing frequency and MV were measured and recorded during the exposure. Blood samples were collected for inorganic serum iodide and the globin adduct S-methylcysteine (SMC) as biomarkers of systemic kinetics immediately following exposure. No significant reductions in breathing frequency were observed for either rats or rabbits. Significant changes in minute volume were demonstrated by both rats and rabbits; however, the changes observed in rats were not concentration dependent. The MeI-induced changes in MV resulted in significant differences in the total volume of test substance atmosphere inhaled over the 6-h period. Rats demonstrated a concentration-dependent increase in both inorganic serum iodide and SMC. Rabbits exposed to 20 ppm MeI demonstrated a significant increase of inorganic serum iodide; SMC was also increased but was not statistically significant. The results of this study are consistent with previous kinetic studies with MeI, and the data presented here can be integrated into a computational fluid dynamics physiologically based pharmacokinetic model for both rats and rabbits.

Diet-induced obesity increases the frequency of Pig-a mutant erythrocytes in male C57BL/6J mice.

PubMed

Wickliffe, Jeffrey K; Dertinger, Stephen D; Torous, Dorothea K; Avlasevich, Svetlana L; Simon-Friedt, Bridget R; Wilson, Mark J

2016-12-01

Obesity increases the risk of a number of chronic diseases in humans including several cancers. Biological mechanisms responsible for such increased risks are not well understood at present. Increases in systemic inflammation and oxidative stress, endogenous production of mutagenic metabolites, altered signaling in proliferative pathways, and increased sensitivity to exogenous mutagens and carcinogens are some of the potential contributing factors. We hypothesize that obesity creates an endogenously mutagenic environment in addition to increasing the sensitivity to environmental mutagens. To test this hypothesis, we examined two in vivo genotoxicity endpoints. Pig-a mutant frequencies and micronucleus frequencies were determined in blood cells in two independent experiments in 30-week old male mice reared on either a high-fat diet (60% calories from fat) that exhibit an obese phenotype or a normal-fat diet (10% calories from fat) that do not exhibit an obese phenotype. Mice were assayed again at 52 weeks of age in one of the experiments. N-ethyl-N-nitrosourea (ENU) was used as a positive mutation control in one experiment. ENU induced a robust Pig-a mutant and micronucleus response in both phenotypes. Obese, otherwise untreated mice, did not differ from non-obese mice with respect to Pig-a mutant frequencies in reticulocytes or micronucleus frequencies. However, such mice, had significantly higher and sustained Pig-a mutant frequencies (increased 2.5-3.7-fold, p < 0.02) in erythrocytes as compared to non-obese mice (based on measurements collected at 30 weeks or 30 and 52 weeks of age). This suggests that obesity, in the absence of exposure to an exogenous mutagen, is itself mutagenic. Environ. Mol. Mutagen. 57:668-677, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Improved Characteristics of Laser Source of Ions Using a Frequency Mode Laser

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

Khaydarov, R. T.

2008-04-07

We used a mass-spectrometric method to investigate the characteristics of laser-produced plasma ions depending on the nature of the target and on the parameters of the laser radiation. Experiments are carried out on porous Y{sub 2}O{sub 3} targets with different densities {rho}, subjected to a laser radiation, where the laser works in a frequency mode (v = l-12 Hz). We found that the laser frequency has a significant effect on the parameters of plasma ions: with increasing the frequency of the laser the charge, energy and intensity of ions increase for a given parameters of the target. This effect ismore » more pronounced for small densities of the target. We related these two effects to a non-linear ionization process in the plasma due to the formation of dense plasma volume inside the sample absorbing the laser radiation and to the change of the focusing conditions in the case of the frequency mode laser.« less

Quantitative photoacoustic characterization of blood clot in blood: A mechanobiological assessment through spectral information

NASA Astrophysics Data System (ADS)

Biswas, Deblina; Vasudevan, Srivathsan; Chen, George C. K.; Sharma, Norman

2017-02-01

Formation of blood clots, called thrombus, can happen due to hyper-coagulation of blood. Thrombi, while moving through blood vessels can impede blood flow, an important criterion for many critical diseases like deep vein thrombosis and heart attacks. Understanding mechanical properties of clot formation is vital for assessment of severity of thrombosis and proper treatment. However, biomechanics of thrombus is less known to clinicians and not very well investigated. Photoacoustic (PA) spectral response, a non-invasive technique, is proposed to investigate the mechanism of formation of blood clots through elasticity and also differentiate clots from blood. Distinct shift (increase in frequency) of the PA response dominant frequency during clot formation is reported. In addition, quantitative differentiation of blood clots from blood has been achieved through parameters like dominant frequency and spectral energy of PA spectral response. Nearly twofold increases in dominant frequency in blood clots compared to blood were found in the PA spectral response. Significant changes in energy also help in quantitatively differentiating clots from blood, in the blood. Our results reveal that increase in density during clot formation is reflected in the PA spectral response, a significant step towards understanding the mechanobiology of thrombus formation. Hence, the proposed tool, in addition to detecting thrombus formation, could reveal mechanical properties of the sample through quantitative photoacoustic spectral parameters.

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

Harrison, F.L.; Rice, D.W. Jr.; Moore, D.H.

Traditional bioassays are unsuitable for assessing sublethal effects of low levels of radioactivity because mortality and phenotypic responses are not anticipated. We compared the usefulness of chromosomal aberration (CA) and sister chromatid exchange (SCE) induction as measures of low-level radiation effects in a sediment-dwelling marine worm, Neanthes arenaceodentata. Newly hatched larvae were exposed to two radiation exposure regimes. Groups of 100 larvae were exposed to either x rays delivered at high dose rates (0.7 Gy min/sup -1/) or to /sup 60/Co gamma rays delivered at low dose rates (4.8 X 10/sup -5/ to 1.2 X 10/sup -1/ Gy h/sup -1/).more » After irradiation, the larvae were exposed to 3 X 10/sup -5/M bromodeoxyuridine (BrdUrd) for 28 h (x-ray-irradiated larvae) or for 54 h (/sup 60/Co-irradiated larvae). Slides of larval cells were prepared for observation of CAs and SCEs. Frequencies of CAs were determined in first division cells; frequencies of SCEs were determined in second division cells. Results from x-ray irradiation indicated that dose-related increases occur in chromosome and chromatid deletions, but an x-ray dose greater than or equal to 2 Gy was required to observe a significant increase. Worm larvae receiving /sup 60/Co irradiation showed elevated SCE frequencies; a significant increase in SCE frequency was observed at 0.6 Gy. 49 references, 2 figures.« less

Inter-hemispheric electroencephalography coherence analysis: assessing brain activity during monotonous driving.

PubMed

Jap, Budi Thomas; Lal, Sara; Fischer, Peter

2010-06-01

The current study investigated the effect of monotonous driving on inter-hemispheric electroencephalography (EEG) coherence. Twenty-four non-professional drivers were recruited to perform a fatigue instigating monotonous driving task while 30 channels of EEG were simultaneously recorded. The EEG recordings were then divided into 5 equal sections over the entire driving period for analysis. Inter-hemispheric coherence was computed from 5 homologous EEG electrode pairs (FP1-FP2, C3-C4, T7-T8, P7-P8, and O1-O2) for delta, theta, alpha and beta frequency bands. Results showed that frontal and occipital inter-hemispheric coherence values were significantly higher than central, parietal, and temporal sites for all four frequency bands (p<0.0001). In the alpha frequency band, significant difference was found between earlier and later driving sections (p=0.02). The coherence values in all EEG frequency bands were slightly increased at the end of the driving session, except for FP1-FP2 electrode pair, which showed no significant change in coherence in the beta frequency band at the end of the driving session. Copyright 2010 Elsevier B.V. All rights reserved.

Micronucleus frequency in Danish schoolchildren and their mothers from the DEMOCOPHES population.

PubMed

Mørck, Thit A; Loock, Kim Vande; Poulsen, Maria Bech; Siersma, Volkert D; Nielsen, Jeanette K S; Hertel, Ole; Kirsch-Volders, Micheline; Knudsen, Lisbeth E

2016-01-01

Micronucleus (MN) frequency is a biomarker for early genetic effects which is often used in human biomonitoring studies. Increased frequency of micronuclei has been associated with high levels of traffic exposure. Further high MN frequency was found predictive for cancer development in several studies of adults. In the present study, the MN frequency in blood samples from the Danish participants of the European pilot project DEMOCOPHES was analysed and related to the area of residence, self-reported and calculated exposure to road traffic as well as to mercury in hair and blood concentrations of persistent organic pollutants and dioxin-like activity measured in the same participants. The MN frequency analysis was performed with the cytokinesis-block micronucleus (CBMN) assay and included 100 children and 119 mothers. We found a significant correlation between mothers and children in the levels of micronuclei in 1000 binucleated T lymphocytes (‰MNBN) and in the proliferation index. Further the levels of ‰MNBN were significantly higher in mothers compared with their children. No significant associations were found for ‰MNBN for traffic related exposure in neither children nor their mothers. In children, a 2.5 times higher micronuclei in mononuclear T lymphocytes were found in children living within 50 m of a busy road, however, this was not found in mothers or in MNBN and the effect of exposure to road traffic on MN frequency needs further investigation. No significant associations were found between MN frequencies and the other biomarkers measured in the same participants. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Rheological characterization of composites using a vertical oscillation rheometer.

PubMed

Lee, In Bog; Cho, Byeong Hoon; Son, Ho Hyun; Um, Chung Moon

2007-04-01

The purpose of this study was to investigate the viscoelastic properties related to the handling characteristics of composites. A custom-designed vertical oscillation rheometer (VOR) was used for the rheological measurements of composites. The VOR consists of three parts: (1) a measuring unit, (2) a deformation induction unit, and (3) a force-detecting unit. Two medium-viscous composites, Z100 and Z250, and two packable composites, P60 and SureFil, were tested. A dynamic oscillatory test was used to evaluate the storage modulus (E'), loss modulus (E''), and loss tangent (tan delta) of the composites as a function of frequency (omega) from 0.1 to 20Hz at 23 degrees C. The E' and E'' increased with increasing frequency and showed differences in magnitude among brands. The complex moduli E* of the composites at omega=2 Hz, normalized to that of Z100, were 2.16 (Z250), 4.80 (P60), and 25.21 (SureFil). The magnitudes and frequency characteristic of loss tangent differed significantly among brands. The relationship among the complex modulus E*, the phase angle delta, and the frequency omega was represented by the frequency domain phasor form E*(omega)e(idelta)=E*(omega) angledelta. The viscoelasticities of composites, which influence handling characteristics, are significantly different among brands. The VOR is a relatively simple device for the dynamic rheological measurement of dental composites. The loci of the frequency domain phasor plots in a complex plane are a valuable method of representing the viscoelastic properties of composites.

Potential association of vacuum cleaning frequency with an altered gut microbiota in pregnant women and their 2-year-old children.

PubMed

Avershina, Ekaterina; Ravi, Anuradha; Storrø, Ola; Øien, Torbjørn; Johnsen, Roar; Rudi, Knut

2015-12-21

Westernized lifestyle and hygienic behavior have contributed to dramatic changes in the human-associated microbiota. This particularly relates to indoor activities such as house cleaning. We therefore investigated the associations between washing and vacuum cleaning frequency and the gut microbiota composition in a large longitudinal cohort of mothers and their children. The gut microbiota composition was determined using 16S ribosomal RNA (rRNA) gene Illumina deep sequencing. We found that high vacuum cleaning frequency about twice or more a week was associated with an altered gut microbiota composition both during pregnancy and for 2-year-old children, while there were no associations with house washing frequency. In total, six Operational Taxonomic Units (OTUs) showed significant False Discovery Rate (FDR) corrected associations with vacuum cleaning frequency for mothers (two positive and four negative) and five for 2-year-old children (four positive and one negative). For mothers and the 2-year-old children, OTUs among the dominant microbiota (average >5 %) showed correlation to vacuum cleaning frequency, with an increase in Faecalibacterium prausnitzii for mothers (p = 0.013, FDR corrected), and Blautia sp. for 2-year children (p = 0.012, FDR corrected). Bacteria showing significant associations are among the dominant gut microbiota, which may indicate indirect immunomodulation of the gut microbiota possibly through increased allergen (dust mites) exposure as a potential mechanism. However, further exploration is needed to unveil mechanistic details.

Enhanced ozone production in a pulsed dielectric barrier discharge plasma jet with addition of argon to a He-O2 flow gas

NASA Astrophysics Data System (ADS)

Sands, Brian; Ganguly, Biswa; Scofield, James

2013-09-01

Ozone production in a plasma jet DBD driven with a 20-ns risetime unipolar pulsed voltage can be significantly enhanced using helium as the primary flow gas with an O2 coflow. The overvolted discharge can be sustained with up to a 5% O2 coflow at <20 kHz pulse repetition frequency at 13 kV applied voltage. Ozone production scales with the pulse repetition frequency up to a ``turnover frequency'' that depends on the O2 concentration, total gas flow rate, and applied voltage. For example, peak ozone densities >1016 cm-3 were measured with 3% O2 admixture and <3 W input power at a 12 kHz turnover frequency. A further increase in the repetition frequency results in increased discharge current and 777 nm O(5 P) emission, but decreased ozone production and is followed by a transition to a filamentary discharge mode. The addition of argon at concentrations >=5% reduces the channel conductivity and shifts the turnover frequency to higher frequencies. This results in increased ozone production for a given applied voltage and gas flow rate. Time-resolved Ar(1s5) and He(23S1) metastable densities were acquired along with discharge current and ozone density measurements to gain insight into the mechanisms of optimum ozone production.

Enhancement of frequency domain indices of heart rate variability by cholinergic stimulation with pyridostigmine bromide.

PubMed

Zarei, Ali Asghar; Foroutan, Seyyed Abbas; Foroutan, Seyyed Mohsen; Erfanian Omidvar, Abbas

2011-01-01

Pyridostigmine bromide (PB) is a reversible cholinesterase inhibitor. The aim of this study was to determine the effect of orally administration of single dose sustained-released tablet of pyridostigmine bromide (PBSR) on the frequency domain indices of heart rate variability (HRV). Thirty-two healthy young men were participated in this study. They were divided into 2 groups; the pyridostigmine group (n = 22) and the placebo group (n = 10). Electrocardiogram (ECG) was recorded at 10, 30, 60, 90, 120, 150, 180, 210, 240, 300 and 420 min after PBSR administration. At each time, simultaneously, a blood sample was prepared and PB plasma concentration was measured by high-performance liquid chromatography (HPLC) method. Statistical analysis showed that in different indices of HRV, there is a significant increase in low frequency (LF) band at 300 min, but no difference in high frequency band (HF). It also showed significant decreases in normalized high frequency band (Hfnu), normalized low frequency band (Lfnu) and LF/HF ratio at 120, 240 and 300 min after PBSR administration. Maximum plasma concentration of PB was 150 min after the administration. In conclusion, administration of a single dose PBSR can enhance the frequency domains indices of HRV and improvesympathovagal balance.

The changes in the frequency of daily precipitation in Urmia Lake basin, Iran

NASA Astrophysics Data System (ADS)

Salehi Bavil, Sepideh; Zeinalzadeh, Kamran; Hessari, Behzad

2017-06-01

Urmia Lake, as one of the most valuable saline ecosystems in the world, has faced a sharp drop in the water level in recent years. The trend studies of climatic parameters can be effective in identifying the responsible factors and managing this crisis. This research investigated the frequency trend of daily precipitation in the ranges of less than 5 mm, 5-10 mm, 10-15 mm, 15-20 mm, and more than 20 mm in the Urmia Lake basin. The trend was assessed using Mann-Kendall, Spearman Rho and linear regression tests on 60 stations during a period of 30 years (1981 to 2011). The results showed that in all the three tests, the frequency of daily precipitation of less than 5 mm had a significant increase at 1% level. The 5-10 mm range displayed no significant trend, while the 10-15 mm range showed a significantly decreasing trend. The frequency in the 15-20 mm and above 20 mm ranges showed an insignificant falling trend. The analysis also indicated jumps in 1996 and 1999 (almost coinciding with the sharp drop in the lake's water level). In other words, the frequency trends of daily precipitation with small amounts (as a result, high evapotranspiration loss) were increasing and with large amounts were decreasing. This can be a contributor to reduced run-off and, hence, decreased water entering the lake. The results emphasize the need for changes in the management and consumption of water resources in the basin, in order to adapt to the climatic change.

Increased frequency of DNA deletions in pink-eyed unstable mice carrying a mutation in the Werner syndrome gene homologue.

PubMed

Lebel, Michel

2002-01-01

Werner syndrome (WS) is a rare autosomal recessive disorder characterized by genomic instability and the premature onset of a number of age-related diseases, including cancers. Accumulating evidence indicates that the WS gene product is involved in resolving aberrant DNA structures that may arise during the process of DNA replication and/or transcription. To estimate the frequency of DNA deletions directly in the skin of mouse embryos, mice with a deletion of part of the murine WRN helicase domain were created. These mutant mice were then crossed to the pink-eyed unstable animals, which have a 70 kb internal duplication at the pink-eyed dilution (p) gene. This report indicates that the frequency of deletion of the duplicated sequence at the p locus is elevated in mice with a mutation in the WRN allele when compared with wild-type mice. In addition, the inhibitor of topoisomerase I camptothecin also increases the frequency of deletion at the p locus. This frequency is even more elevated in WRN mutant mice treated with camptothecin. In contrast, while the inhibition of poly(ADP-ribose) polymerase (PARP) activity by 3-aminobenzamide increases the frequency of DNA deletion, mutant WRN mice are not significantly more sensitive to the inhibition of PARP activity than wild-type animals.

Drooling in Parkinson's Disease: Evidence of a Role for Divided Attention.

PubMed

Reynolds, Hannah; Miller, Nick; Walker, Richard

2018-05-21

Drooling is a frequently reported symptom in Parkinson's Disease (PD) with significant psychosocial impact and negative health consequences including silent aspiration of saliva with the associated risk of respiratory infections. It is suggested that in PD drooling is associated with inefficient oropharyngeal swallowing which reduces the effective clearance of saliva rather than hyper-salivation. This is compounded by unintended mouth opening and flexed posture increasing anterior loss of saliva. It is reported to occur most frequently during cognitively distracting concurrent tasks suggesting an impact from divided attention in a dual-task situation. However, this supposition has not been systematically examined. This study assessed whether frequency of saliva swallows reduced, and drooling severity and frequency increased, when people with PD engaged in a cognitively distracting task. 18 patients with idiopathic PD reporting daytime drooling on the Unified Parkinson's Disease Rating Scale (UPDRS) were recruited. They completed the Radboud Oral Motor Inventory for PD saliva questionnaire and the Montreal Cognitive Assessment. UPDRS drooling score, disease stage, duration, gender, and age were recorded. Swallow frequency and drooling severity and frequency were measured at rest and during a distracting computer-based language task. There was no significant difference between drooling severity at rest and during distraction (Wilcoxon signed rank test z = - 1.724, p = 0.085). There was a significant difference between at rest and distraction conditions for both drooling frequency (Wilcoxon signed rank test z = - 2.041, p = 0.041) and swallow frequency (Wilcoxon signed rank test z = - 3.054, p = 0.002). Participants swallowed less frequently and drooled more often during the distraction task. The frequency of saliva swallows and drooling are affected by divided attention in a dual-task paradigm. Further studies are needed to explore the exact role of attention in saliva management and the clinical applications in assessment and treatment.

Task-induced frequency modulation features for brain-computer interfacing.

PubMed

Jayaram, Vinay; Hohmann, Matthias; Just, Jennifer; Schölkopf, Bernhard; Grosse-Wentrup, Moritz

2017-10-01

Task-induced amplitude modulation of neural oscillations is routinely used in brain-computer interfaces (BCIs) for decoding subjects' intents, and underlies some of the most robust and common methods in the field, such as common spatial patterns and Riemannian geometry. While there has been some interest in phase-related features for classification, both techniques usually presuppose that the frequencies of neural oscillations remain stable across various tasks. We investigate here whether features based on task-induced modulation of the frequency of neural oscillations enable decoding of subjects' intents with an accuracy comparable to task-induced amplitude modulation. We compare cross-validated classification accuracies using the amplitude and frequency modulated features, as well as a joint feature space, across subjects in various paradigms and pre-processing conditions. We show results with a motor imagery task, a cognitive task, and also preliminary results in patients with amyotrophic lateral sclerosis (ALS), as well as using common spatial patterns and Laplacian filtering. The frequency features alone do not significantly out-perform traditional amplitude modulation features, and in some cases perform significantly worse. However, across both tasks and pre-processing in healthy subjects the joint space significantly out-performs either the frequency or amplitude features alone. This result only does not hold for ALS patients, for whom the dataset is of insufficient size to draw any statistically significant conclusions. Task-induced frequency modulation is robust and straight forward to compute, and increases performance when added to standard amplitude modulation features across paradigms. This allows more information to be extracted from the EEG signal cheaply and can be used throughout the field of BCIs.

Frequency specificity and left-ear advantage of medial olivocochlear efferent modulation: a study based on stimulus frequency otoacoustic emission.

PubMed

Xing, Dongjia; Gong, Qin

2017-09-06

The medial olivocochlear (MOC) bundle is an auditory nucleus that projects efferent nerve fibers to the outer hair cells (OHCs) for synaptic innervation. The aim of the present study was to investigate the possible existence of frequency and ear specificity in MOC efferent modulation, as well as how MOC activation influences cochlear tuning. Stimulus frequency otoacoustic emissions (SFOAEs) were used to study MOC efferent modulation. Therefore, the current experiment was designed to compare the degree of SFOAE suppression in the both ears of 20 individuals at 1, 2, 4, and 8 kHz. We also compared changes in Q10 values of SFOAE suppression tuning curves at 1, 2, and 4 kHz under contralateral acoustic stimulation (CAS) and no-CAS conditions. We observed a significant reduction in SFOAE magnitude in the CAS condition compared with the no-CAS condition at 1 and 2 kHz in the left ear. A significant difference in CAS suppression was also found between the left and right ears at 1 and 2 kHz, with larger CAS suppression in the left ear. CAS further produced a statistically significant increase in the Q10 value at 1 kHz and a significant reduction in Q10 values at 2 and 4 kHz. These findings suggest a left-ear advantage in terms of CAS-induced MOC efferent SFOAE suppression, with larger MOC efferent modulation for lower frequencies, and cochlear tuning was sharpened by means of MOC activation at lower frequencies and broadened at higher frequencies.

Associations Between Renal Duplex Parameters and Adverse Cardiovascular Events in the Elderly: A Prospective Cohort Study

PubMed Central

Pearce, Jeffrey D.; Craven, Timothy E.; Edwards, Matthew S.; Corriere, Matthew A.; Crutchley, Teresa A.; Fleming, Shawn H.; Hansen, Kimberley J.

2010-01-01

Background Atherosclerotic renovascular disease is associated with an increased risk of cardiovascular disease (CVD) events. This study examines associations between Doppler-derived parameters from the renal artery and renal parenchyma and all-cause mortality and fatal and nonfatal CVD events in a cohort of elderly Americans. Study Design Cohort study. Setting A subset of participants from the Cardiovascular Health Study (CHS). Through an ancillary study, 870 (70% recruitment) Forsyth County, NC, CHS participants consented to undergo renal duplex sonography to define the prevalence of renovascular disease in the elderly, resulting in 726 (36% men; mean age, 77 years) technically adequate complete studies included in this investigation. Predictor Renal duplex sonography–derived Doppler signals from the main renal arteries and renal parenchyma. Spectral analysis from Doppler-shifted frequencies and angle of insonation were used to estimate renal artery peak systolic and end diastolic velocity (both in meters per second). Color Doppler was used to identify the corticomedullary junction. Using a 3-mm Doppler sample, the parenchymal peak systolic and end diastolic frequency shift (both in kilohertz) were obtained. Resistive index was calculated as (1 – [end diastolic frequency shift/peak systolic frequency shift]) using Doppler samples from the hilar arteries of the left or right kidney with the higher main renal artery peak systolic velocity. Outcomes & Measurements Proportional hazard regression analysis was used to determine associations between renal duplex sonography–derived Doppler signals and CVD events and all-cause mortality adjusted for accepted cardiovascular risk factors. Index CVD outcomes were defined as coronary events (angina, myocardial infarction, and coronary artery bypass grafting/percutaneous coronary intervention), cerebrovascular events (stroke or transient ischemic attack), and any CVD event (angina, congestive heart failure, myocardial infarction, stroke, transient ischemic attack, and coronary artery bypass grafting [CABG]/percutaneous transluminal coronary intervention [PTCI]). Results During follow-up, 221 deaths (31%), 229 CVD events (32%), 122 coronary events (17%), and 92 cerebrovascular events (13%) were observed. Renal duplex sonography–derived Doppler signals from the renal parenchyma were associated independently with all-cause mortality and CVD outcomes. In particular, increased parenchymal end diastolic frequency shift was associated significantly with any CVD event (HR, 0.73; 95% CI, 0.62-0.87; P < 0.001). Marginally significant associations were observed between increases in parenchymal end diastolic frequency shift and decreased risk of death (HR, 0.86; 95% CI, 0.73-1.00; P = 0.06) and decreased risk of cerebrovascular events (HR, 0.78; 95% CI, 0.61-1.01; P = 0.06). Parenchymal end diastolic frequency shift was not significantly predictive of coronary events (HR, 0.84; 95% CI, 0.67-1.06; P = 0.1). Limitations CHS participants showed a “healthy cohort” effect that may underestimate the rate of CVD events in the general population. Conclusion Renal duplex sonographic Doppler signals from the renal parenchyma showed significant associations with subsequent CVD events after controlling for other significant risk factors. In particular, a standard deviation increase in parenchymal end diastolic frequency shift was associated with 27% risk reduction in any CVD event. PMID:20116688

Frequency Dependence of Ultrasound Neurostimulation in the Mouse Brain

PubMed Central

Ye, Patrick Peiyong; Brown, Julian R.; Pauly, Kim Butts

2016-01-01

Ultrasound neuromodulation holds promise as a non-invasive technique for neuromodulation of the central nervous system. However, much remains to be determined about how the technique can be transformed into a useful technology, including the effect of ultrasound frequency. Previous studies have demonstrated neuromodulation in vivo using frequencies less than 1 MHz, with a trend towards improved efficacy with lower frequency. However, using higher frequencies could offer improved ultrasound spatial resolution. We investigate the ultrasound neuromodulation effects in mice at various frequencies both below and above 1 MHz and find that frequencies up to 2.9 MHz can still be effective for generating motor responses, but also confirm that as frequency increases, sonications require significantly more intensity to achieve equivalent efficacy. We argue that our results provide evidence that favors either a particle displacement or a cavitation-based mechanism for the phenomenon of ultrasound neuromodulation. PMID:27090861

More frequent showers and thunderstorms under a warming climate: evidence observed in Northern Eurasia

NASA Astrophysics Data System (ADS)

Ye, H.; Fetzer, E. J.; Wong, S.; Lambrigtsen, B.; Wang, T.; Chen, L. L.; Von, D.

2015-12-01

This study uses historical records of synoptic observations over northern Eurasia to examine changing frequency of precipitation associated with large synoptic events versus convective and thunderstorm activities. We found days associated with showers and precipitation accompanied by thunderstorms have been increasing in general during the study period of 1966-2000 while the total wet day frequency has been decreasing in all seasons. This study suggests increasing convective and severe weather-related precipitation events may be a significant contributor to higher intensity and more extreme precipitation under a warming climate.

Effect of intravesical Resiniferatoxin (RTX) on lower urinary tract symptoms, urodynamic parameters, and quality of life of patients with urodynamic increased bladder sensation.

PubMed

Apostolidis, Apostolos; Gonzales, Gwendoline E; Fowler, Clare J

2006-12-01

Intravesical resiniferatoxin (RTX) has been used with variable efficacy in the treatment of detrusor overactivity (DO). Patients with interstitial cystitis (IC) failed to benefit from this treatment, but a single placebo-controlled study in patients with non-IC painful bladders showed that RTX was effective in the short-term. We investigated the efficacy of intravesical RTX in patients with urgency and frequency due to increased bladder sensation. Patients with intractable urgency and frequency, with or without urgency incontinence or bladder pain/discomfort, and with no urodynamic evidence of DO were recruited. After a single intravesical instillation of 100ml 50 nM RTX solution, patients were followed at 1, 3, and 6 mo for changes in urodynamics, bladder diary, the King's Health Questionnaire (KHQ), and degree of bladder pain. Fifteen patients (mean age, 52.5 yr) were treated. RTX significantly improved maximum cystometric capacity, volume at first desire to void, mean micturition volume, 24-h frequency, and daytime frequency for up to 6 mo after treatment. The overall KHQ score improved at all time points, with sustained improvements in the Symptom Severity, Incontinence Impact, and Personal Relationships domains. A >50% decrease in pain was reported by five of seven patients with painful bladders at 1 mo, but only one of seven at 6 mo. In our small open-label study, a single administration of intravesical RTX in patients with frequency and urgency due to increased bladder sensation significantly improved lower urinary tract symptoms, urodynamic parameters, and quality of life for up to 6 mo.

An increased rectal maximum tolerable volume and long anal canal are associated with poor short-term response to biofeedback therapy for patients with anismus with decreased bowel frequency and normal colonic transit time.

PubMed

Rhee, P L; Choi, M S; Kim, Y H; Son, H J; Kim, J J; Koh, K C; Paik, S W; Rhee, J C; Choi, K W

2000-10-01

Biofeedback is an effective therapy for a majority of patients with anismus. However, a significant proportion of patients still failed to respond to biofeedback, and little has been known about the factors that predict response to biofeedback. We evaluated the factors associated with poor response to biofeedback. Biofeedback therapy was offered to 45 patients with anismus with decreased bowel frequency (less than three times per week) and normal colonic transit time. Any differences in demographics, symptoms, and parameters of anorectal physiologic tests were sought between responders (in whom bowel frequency increased up to three times or more per week after biofeedback) and nonresponders (in whom bowel frequency remained less than three times per week). Thirty-one patients (68.9 percent) responded to biofeedback and 14 patients (31.1 percent) did not. Anal canal length was longer in nonresponders than in responders (4.53 +/- 0.5 vs. 4.08 +/- 0.56 cm; P = 0.02), and rectal maximum tolerable volume was larger in nonresponders than in responders. (361 +/- 87 vs. 302 +/- 69 ml; P = 0.02). Anal canal length and rectal maximum tolerable volume showed significant differences between responders and nonresponders on multivariate analysis (P = 0.027 and P = 0.034, respectively). This study showed that a long anal canal and increased rectal maximum tolerable volume are associated with poor short-term response to biofeedback for patients with anismus with decreased bowel frequency and normal colonic transit time.

Hyper telomere recombination accelerates replicative senescence and may promote premature aging

PubMed Central

Hagelstrom, R. Tanner; Blagoev, Krastan B.; Niedernhofer, Laura J.; Goodwin, Edwin H.; Bailey, Susan M.

2010-01-01

Werner syndrome and Bloom syndrome result from defects in the RecQ helicases Werner (WRN) and Bloom (BLM), respectively, and display premature aging phenotypes. Similarly, XFE progeroid syndrome results from defects in the ERCC1-XPF DNA repair endonuclease. To gain insight into the origin of cellular senescence and human aging, we analyzed the dependence of sister chromatid exchange (SCE) frequencies on location [i.e., genomic (G-SCE) vs. telomeric (T-SCE) DNA] in primary human fibroblasts deficient in WRN, BLM, or ERCC1-XPF. Consistent with our other studies, we found evidence of elevated T-SCE in telomerase-negative but not telomerase-positive backgrounds. In telomerase-negative WRN-deficient cells, T-SCE—but not G-SCE—frequencies were significantly increased compared with controls. In contrast, SCE frequencies were significantly elevated in BLM-deficient cells irrespective of genome location. In ERCC1-XPF-deficient cells, neither T- nor G-SCE frequencies differed from controls. A theoretical model was developed that allowed an in silico investigation into the cellular consequences of increased T-SCE frequency. The model predicts that in cells with increased T-SCE, the onset of replicative senescence is dramatically accelerated even though the average rate of telomere loss has not changed. Premature cellular senescence may act as a powerful tumor-suppressor mechanism in telomerase-deficient cells with mutations that cause T-SCE levels to rise. Furthermore, T-SCE-driven premature cellular senescence may be a factor contributing to accelerated aging in Werner and Bloom syndromes, but not XFE progeroid syndrome. PMID:20798040

Habitat-dependent changes in vigilance behaviour of Red-crowned Crane influenced by wildlife tourism.

PubMed

Li, Donglai; Liu, Yu; Sun, Xinghai; Lloyd, Huw; Zhu, Shuyu; Zhang, Shuyan; Wan, Dongmei; Zhang, Zhengwang

2017-11-30

The Endangered Red-crowned Crane (Grus japonensis) is one of the most culturally iconic and sought-after species by wildlife tourists. Here we investigate how the presence of tourists influence the vigilance behaviour of cranes foraging in Suaeda salsa salt marshes and S. salsa/Phragmites australis mosaic habitat in the Yellow River Delta, China. We found that both the frequency and duration of crane vigilance significantly increased in the presence of wildlife tourists. Increased frequency in crane vigilance only occurred in the much taller S. salsa/P. australis mosaic vegetation whereas the duration of vigilance showed no significant difference between the two habitats. Crane vigilance declined with increasing distance from wildlife tourists in the two habitats, with a minimum distance of disturbance triggering a high degree of vigilance by cranes identified at 300 m. The presence of wildlife tourists may represent a form of disturbance to foraging cranes but is habitat dependent. Taller P. australis vegetation serves primarily as a visual obstruction for cranes, causing them to increase the frequency of vigilance behaviour. Our findings have important implications for the conservation of the migratory red-crowned crane population that winters in the Yellow River Delta and can help inform visitor management.

Biomonitoring of genotoxic risk in agricultural workers from five colombian regions: association to occupational exposure to glyphosate.

PubMed

Bolognesi, C; Carrasquilla, G; Volpi, S; Solomon, K R; Marshall, E J P

2009-01-01

In order to assess possible human effects associated with glyphosate formulations used in the Colombian aerial spray program for control of illicit crops, a cytogenetic biomonitoring study was carried out in subjects from five Colombian regions, characterized by different exposure to glyphosate and other pesticides. Women of reproductive age (137 persons 15-49 yr old) and their spouses (137 persons) were interviewed to obtain data on current health status, history, lifestyle, including past and current occupational exposure to pesticides, and factors including those known to be associated with increased frequency of micronuclei (MN). In regions where glyphosate was being sprayed, blood samples were taken prior to spraying (indicative of baseline exposure), 5 d after spraying, and 4 mo after spraying. Lymphocytes were cultured and a cytokinesis-block micronucleus cytome assay was applied to evaluate chromosomal damage and cytotoxicity. Compared with Santa Marta, where organic coffee is grown without pesticides, the baseline frequency of binucleated cells with micronuclei (BNMN) was significantly greater in subjects from the other four regions. The highest frequency of BNMN was in Boyaca, where no aerial eradication spraying of glyphosate was conducted, and in Valle del Cauca, where glyphosate was used for maturation of sugar cane. Region, gender, and older age (> or =35 yr) were the only variables associated with the frequency of BNMN measured before spraying. A significant increase in frequency of BNMN between first and second sampling was observed in Narino, Putumayo, and Valle immediately (<5 d) after spraying. In the post-spray sample, those who reported direct contact with the eradication spray showed a higher quantitative frequency of BNMN compared to those without glyphosate exposure. The increase in frequency of BNMN observed immediately after the glyphosate spraying was not consistent with the rates of application used in the regions and there was no association between self-reported direct contact with eradication sprays and frequency of BNMN. Four months after spraying, a statistically significant decrease in the mean frequency of BNMN compared with the second sampling was observed in Narino, but not in Putumayo and Valle del Cauca. Overall, data suggest that genotoxic damage associated with glyphosate spraying for control of illicit crops as evidenced by MN test is small and appears to be transient. Evidence indicates that the genotoxic risk potentially associated with exposure to glyphosate in the areas where the herbicide is applied for coca and poppy eradication is low.

Dietary food groups intake and cooking methods associations with pancreatic cancer: a case-control study.

PubMed

Ghorbani, Zeinab; Hekmatdoost, Azita; Zinab, Hassan Eini; Farrokhzad, Solmaz; Rahimi, Roya; Malekzadeh, Reza; Pourshams, Akram

2015-05-01

The role of dietary habits in the etiology of pancreatic cancer (PC) has not yet been well elucidated. The aim of the present study was to examine the association of the frequency of different food groups' intake and their cooking methods with PC risk based on a well-designed case-control study. A case-control study including 307 PC patients and 322 controls referred to four tertiary endosonography centers was conducted from January 2011 to January 2014 to compare the frequency intake of different food items and their cooking methods between cases and controls. After adjustment for gender, age, body mass index, years of education, diabetes and alcohol history, smoking status, and opium use, a significant direct relationship was observed between PC risk and intake frequency (time/week) of bread (OR = 1.50; 95 % CI 1.05-2.13; p-value 0.024), rice (OR = 2.10; 95 % CI 1.15-3.82; p for trend 0.034), and red meat (OR = 2.25; 95 % CI 1.22-4.14; p for trend 0.033) (time/day), when comparing the highest category of intake frequency with the lowest, while increasing frequency of fish consumption was associated with a lower risk of PC (OR = 0.93; 95 % CI0.59-1.47; p for trend 0.009). Increasing consumption of barbecuing red meat and deep fried vegetables was associated with 67 % and 70 % increased risk of PC (p-value 0.025 and 0.006, respectively). Our results indicate that increased frequency of intake of bread, rice, and red meat (especially barbecued) and deep fried vegetables can aggregate PC risk, while increased frequency of fish consumption can protect against PC. However, more studies are still needed.

Flow and Acoustic Features of a Mach 0.9 Free Jet Using High-Frequency Excitation

NASA Astrophysics Data System (ADS)

Upadhyay, Puja; Alvi, Farrukh

2016-11-01

This study focuses on active control of a Mach 0.9 (ReD = 6 ×105) free jet using high-frequency excitation for noise reduction. Eight resonance-enhanced microjet actuators with nominal frequencies of 25 kHz (StD 2 . 2) are used to excite the shear layer at frequencies that are approximately an order of magnitude higher than the jet preferred frequency. The influence of control on mean and turbulent characteristics of the jet is studied using Particle Image Velocimetry. Additionally, far-field acoustic measurements are acquired to estimate the effect of pulsed injection on noise characteristics of the jet. Flow field measurements revealed that strong streamwise vortex pairs, formed as a result of control, result in a significantly thicker initial shear layer. This excited shear layer is also prominently undulated, resulting in a modified initial velocity profile. Also, the distribution of turbulent kinetic energy revealed that forcing results in increased turbulence levels for near-injection regions, followed by a global reduction for all downstream locations. Far-field acoustic measurements showed noise reductions at low to moderate frequencies. Additionally, an increase in high-frequency noise, mostly dominated by the actuators' resonant noise, was observed. AFOSR and ARO.

Extremely high frequency RF effects on electronics.

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

Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale

The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit boardmore » traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.« less

Radio Frequency Signals in Jupiter's Atmosphere

PubMed

Lanzerotti; Rinnert; Dehmel; Gliem; Krider; Uman; Bach

1996-05-10

During the Galileo probe's descent through Jupiter's atmosphere, under the ionosphere, the lightning and radio emission detector measured radio frequency signals at levels significantly above the probe's electromagnetic noise. The signal strengths at 3 and 15 kilohertz were relatively large at the beginning of the descent, decreased with depth to a pressure level of about 5 bars, and then increased slowly until the end of the mission. The 15-kilohertz signals show arrival direction anisotropies. Measurements of radio frequency wave forms show that the probe passed through an atmospheric region that did not support lightning within at least 100 kilometers and more likely a few thousand kilometers of the descent trajectory. The apparent opacity of the jovian atmosphere increases sharply at pressures greater than about 4 bars.

Zero-lag synchronization and bubbling in delay-coupled lasers.

PubMed

Tiana-Alsina, J; Hicke, K; Porte, X; Soriano, M C; Torrent, M C; Garcia-Ojalvo, J; Fischer, I

2012-02-01

We show experimentally that two semiconductor lasers mutually coupled via a passive relay fiber loop exhibit chaos synchronization at zero lag, and study how this synchronized regime is lost as the lasers' pump currents are increased. We characterize the synchronization properties of the system with high temporal resolution in two different chaotic regimes, namely, low-frequency fluctuations and coherence collapse, identifying significant differences between them. In particular, a marked decrease in synchronization quality develops as the lasers enter the coherence collapse regime. Our high-resolution measurements allow us to establish that synchronization loss is associated with bubbling events, the frequency of which increases with increasing pump current.

Chromosomal analysis of myelodysplastic syndromes among atomic bomb survivors in Nagasaki.

PubMed

Horai, Makiko; Satoh, Shinya; Matsuo, Masatoshi; Iwanaga, Masako; Horio, Kensuke; Jo, Tatsuro; Takasaki, Yumi; Kawaguchi, Yasuhisa; Tsushima, Hideki; Yoshida, Shinichiro; Taguchi, Masataka; Itonaga, Hidehiro; Sawayama, Yasushi; Taguchi, Jun; Imaizumi, Yoshitaka; Hata, Tomoko; Moriuchi, Yukiyoshi; Haase, Detlef; Yoshiura, Koh-Ichiro; Miyazaki, Yasushi

2018-02-01

The myelodysplastic syndromes (MDS) are clonal haematopoietic disorders that develop de novo and also secondary to chemotherapy and/or radiation therapy. We previously demonstrated that the risk of MDS is increased among atomic bomb survivors with significant correlation to radiation dose; however, the clinical characteristics of these survivors have not been well analysed. In this study, we investigated chromosomal abnormalities of MDS among survivors. The frequency of abnormal karyotypes was significantly higher, with more very poor risk karyotypes, according to the revised International Prognostic Scoring System, among those exposed close to the hypocentre compared with unexposed cases. However, abnormal karyotype frequency did not reflect the prognosis of exposed cases with respect to distance from the hypocentre. In addition, there was no difference in prognosis between exposed and unexposed cases. Among proximally exposed cases (<1·5 km from the hypocentre), chromosomal translocations and inversions were more frequent, and the frequency of structural alterations in chromosomes 3, 8, and 11 was significantly increased compared with unexposed cases. These results suggest that chromosomal alterations in MDS among survivors have different features compared with those in de novo or therapy-related MDS. Detailed molecular study is warranted. © 2017 John Wiley & Sons Ltd.

Spectral changes in spontaneous MEG activity across the lifespan

NASA Astrophysics Data System (ADS)

Gómez, Carlos; Pérez-Macías, Jose M.; Poza, Jesús; Fernández, Alberto; Hornero, Roberto

2013-12-01

Objective. The aim of this study is to explore the spectral patterns of spontaneous magnetoencephalography (MEG) activity across the lifespan. Approach. Relative power (RP) in six frequency bands (delta, theta, alpha, beta-1, beta-2 and gamma) was calculated in a sample of 220 healthy subjects with ages ranging from 7 to 84 years. Main results. A significant RP decrease in low-frequency bands (i.e. delta and theta) and a significant increase in high bands (mainly beta-1 and beta-2) were found from childhood to adolescence. This trend was observed until the sixth decade of life, though only slight changes were found. Additionally, healthy aging was characterized by a power increase in low-frequency bands. Our results show that spectral changes across the lifespan may follow a quadratic relationship in delta, theta, alpha, beta-2 and gamma bands with peak ages being reached around the fifth or sixth decade of life. Significance. Our findings provide original insights into the definition of the ‘normal’ behavior of age-related MEG spectral patterns. Furthermore, our study can be useful for the forthcoming MEG research focused on the description of the abnormalities of different brain diseases in comparison to cognitive decline in normal aging.

Advanced Mitigation Process (AMP) for Improving Laser Damage Threshold of Fused Silica Optics

NASA Astrophysics Data System (ADS)

Ye, Xin; Huang, Jin; Liu, Hongjie; Geng, Feng; Sun, Laixi; Jiang, Xiaodong; Wu, Weidong; Qiao, Liang; Zu, Xiaotao; Zheng, Wanguo

2016-08-01

The laser damage precursors in subsurface of fused silica (e.g. photosensitive impurities, scratches and redeposited silica compounds) were mitigated by mineral acid leaching and HF etching with multi-frequency ultrasonic agitation, respectively. The comparison of scratches morphology after static etching and high-frequency ultrasonic agitation etching was devoted in our case. And comparison of laser induce damage resistance of scratched and non-scratched fused silica surfaces after HF etching with high-frequency ultrasonic agitation were also investigated in this study. The global laser induce damage resistance was increased significantly after the laser damage precursors were mitigated in this case. The redeposition of reaction produce was avoided by involving multi-frequency ultrasonic and chemical leaching process. These methods made the increase of laser damage threshold more stable. In addition, there is no scratch related damage initiations found on the samples which were treated by Advanced Mitigation Process.

Effect of Bryophyllum pinnatum versus fenoterol on uterine contractility.

PubMed

Gwehenberger, Birgit; Rist, Lukas; Huch, Renate; von Mandach, Ursula

2004-04-15

To characterise the phytotherapeutic tocolytic Bryophyllum pinnatum in vitro versus the conventional betamimetic, fenoterol, in human myometrium. Contractility (endpoints: area under the curve (AUC), amplitude and frequency of isometric force development) was measured in strips of term myometrium biopsied at caesarean section in 14 women and exposed to increasing concentrations of B. pinnatum versus +/- oxytocin 1 U/l. Inhibition of spontaneous contraction by B. pinnatum was concentration-dependent: 16% at maximum concentration (10(4) mg/l), or 53% that with fenoterol 5 x 10(-8)mol/l. B. pinnatum increased contraction frequency by 91% at constant amplitude and inhibited oxytocin-stimulated contractions by 20% (AUC) at constant amplitude with slightly decreased frequency. Fenoterol decreased contraction AUC by 50% with a significant decrease in frequency. Our in vitro data confirm the tocolytic activity of B. pinnatum observed in alternative medicine centres and may justify further clinical studies.

Advanced Mitigation Process (AMP) for Improving Laser Damage Threshold of Fused Silica Optics

PubMed Central

Ye, Xin; Huang, Jin; Liu, Hongjie; Geng, Feng; Sun, Laixi; Jiang, Xiaodong; Wu, Weidong; Qiao, Liang; Zu, Xiaotao; Zheng, Wanguo

2016-01-01

The laser damage precursors in subsurface of fused silica (e.g. photosensitive impurities, scratches and redeposited silica compounds) were mitigated by mineral acid leaching and HF etching with multi-frequency ultrasonic agitation, respectively. The comparison of scratches morphology after static etching and high-frequency ultrasonic agitation etching was devoted in our case. And comparison of laser induce damage resistance of scratched and non-scratched fused silica surfaces after HF etching with high-frequency ultrasonic agitation were also investigated in this study. The global laser induce damage resistance was increased significantly after the laser damage precursors were mitigated in this case. The redeposition of reaction produce was avoided by involving multi-frequency ultrasonic and chemical leaching process. These methods made the increase of laser damage threshold more stable. In addition, there is no scratch related damage initiations found on the samples which were treated by Advanced Mitigation Process. PMID:27484188

Thrombolysis using multi-frequency high intensity focused ultrasound at MHz range: an in vitro study

NASA Astrophysics Data System (ADS)

Suo, Dingjie; Guo, Sijia; Lin, Weili; Jiang, Xiaoning; Jing, Yun

2015-09-01

High intensity focused ultrasound (HIFU) based thrombolysis has emerged as a promising drug-free treatment approach for ischemic stroke. The large amount of acoustic power required by this approach, however, poses a critical challenge to the future clinical translation. In this study, multi-frequency acoustic waves at MHz range (near 1.5 MHz) were introduced as HIFU excitations to reduce the required power for treatment as well as the treatment time. In vitro bovine blood clots weighing around 150 mg were treated by single-frequency and multi-frequency HIFU. The pulse length was 2 ms for all experiments except the ones where the duty cycle was changed. It was found that dual-frequency thrombolysis efficiency was statistically better than single-frequency under the same acoustic power and excitation condition. When varying the acoustic power but fixing the duty cycle at 5%, it was found that dual-frequency ultrasound can save almost 30% power in order to achieve the same thrombolysis efficiency. In the experiment where the duty cycle was increased from 0.5% to 10%, it was shown that dual-frequency ultrasound can achieve the same thrombolysis efficiency with only half of the duty cycle of single-frequency. Dual-frequency ultrasound could also accelerate the thrombolysis by a factor of 2-4 as demonstrated in this study. No significant differences were found between dual-frequencies with different frequency differences (0.025, 0.05, and 0.1 MHz) and between dual-frequency and triple-frequency. The measured cavitation doses of dual-frequency and triple-frequency excitations were at about the same level but both were significantly higher than that of single-frequency.

Environmental genotoxicity assessment along the transport routes of chemical munitions leading to the dumping areas in the Baltic Sea.

PubMed

Baršienė, Janina; Butrimavičienė, Laura; Grygiel, Włodzimierz; Stunžėnas, Virmantas; Valskienė, Roberta; Greiciūnaitė, Janina; Stankevičiūtė, Milda

2016-02-15

The frequencies of micronuclei (MN), nuclear buds (NB) and nuclear buds on filament (NBf) were examined in 660 specimens of herring (Clupea harengus) collected in 2009-2014 at 65 study stations located mainly along the chemical munition transport routes in the Baltic Sea. The frequency of nuclear abnormalities was strongly increased in herring caught at four stations located close to chemical munition dumping sites, or CWAs - substances (chemical warfare agents) in sediments. Significant increase of MN, NB and NBf was observed in fish caught November 2010-2013 compared to 2009. The most significantly increased genotoxicity responses were recorded in fish caught at stations along CW (chemical weapons) transport routes, close to the Bornholm CW dumping area, in zones with CWAs in sediments and with oil-gas platforms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Trains of electrical stimulation of the trapezius muscles redistribute the frequencies of body oscillations during stance.

PubMed

Nhouvannasak, V; Clément, S; Manto, M

2015-09-01

We investigated the postural effects of trains of electrical stimulation (TES) applied unilaterally or bilaterally on the trapezius muscle in 20 healthy subjects (mean age: 23.1 ± 1.33 years; F/M: 8/12). The anterior-posterior (AP) displacements (AP axis), medio-lateral displacements (ML axis) and total travelled distances (TTW) of the centre of pressure (COP) remained unchanged with TES. However, detailed spectral analysis of COP oscillations revealed a marked decrease of the magnitudes of peak power spectral density (peak PSD) following application of TES. Peak PSD was highly correlated with the intensity of stimulation (P < 0.001 both the AP and ML axes). For the AP axis, the integrals of the sub-bands 0-0.4, 0.4-1.5, 1.5-3 Hz were significantly decreased (P < 0.001), the integrals of the sub-bands 3-5 and 5-8 Hz were not significantly affected (P>0.30) and the integrals of the sub-band 8-10 Hz were significantly increased (P < 0.001). The ratios of the integrals of sub-bands 8-10 Hz/0-3 Hz were markedly enhanced with bilateral TES (P < 0.001). For the ML axis, the effects were striking (P < 0.001) for the sub-bands 0-0.4, 0.4-1.5 and 8-10 Hz. For both the AP and ML axes, a significant inverse linear relationship was found between the intensity of TES and the average speed of COP. We show that TES applied over the trapezius muscles exerts significant and so far unrecognised effects upon oscillations of the COP, decreasing low-frequency oscillations and enhancing high-frequency oscillations. Our data unravel a novel property of the trapezius muscles upon postural control. We suggest that this muscle plays a role of a distributor of low-frequency versus high-frequency sub-bands of frequency during stance. Previous studies have shown that patients with supra-tentorial stroke show an increased peak PSD in low frequencies of body oscillations. Therefore, our findings provide a rationale to assess neurostimulation of the trapezius muscle in the rehabilitation of postural deficits in supra-tentorial stroke.

Ultrasound assisted biogas production from landfill leachate

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

Oz, Nilgün Ayman, E-mail: nilgunayman@comu.edu.tr; Yarimtepe, Canan Can

Highlights: • Effect of low frequency ultrasound pretreatment on leachate was investigated. • Three different ultrasound energy inputs (200, 400 and 600 W/l) was applied. • Low-frequency ultrasound treatment increased soluble COD in landfill leachate. • Application of ultrasound to leachate increased biogas production about 40%. • Application of ultrasound to leachate increased total methane production rate about 20%. - Abstract: The aim of this study is to increase biogas production and methane yield from landfill leachate in anaerobic batch reactors by using low frequency ultrasound as a pretreatment step. In the first part of the study, optimum conditions formore » solubilization of organic matter in leachate samples were investigated using various sonication durations at an ultrasound frequency of 20 kHz. The level of organic matter solubilization during ultrasonic pretreatment experiments was determined by calculating the ratio of soluble chemical oxygen demand (sCOD) to total chemical oxygen demand (tCOD). The sCOD/tCOD ratio was increased from 47% in raw leachate to 63% after 45 min sonication at 600 W/l. Non-parametric Friedman’s test indicated that ultrasonic pretreatment has a significant effect on sCOD parameter for leachate (p < 0.05). In the second part of the study, anaerobic batch reactors were operated for both ultrasonically pretreated and untreated landfill leachate samples in order to assess the effect of sonication on biogas and methane production rate. In anaerobic batch reactor feed with ultrasonically pretreated leachate, 40% more biogas was obtained compared to the control reactor. For statistical analysis, Mann–Whitney U test was performed to compare biogas and methane production rates for raw and pretreated leachate samples and it has been found that ultrasonic pretreatment significantly enhanced biogas and methane production rates from leachate (p < 0.05) in anaerobic batch reactors. The overall results showed that low frequency ultrasound pretreatment can be potentially used for wastewater management especially with integration of anaerobic processes.« less

Mutagenicity of furan in female Big Blue B6C3F1 mice

PubMed Central

Terrell, Ashley N.; Huynh, Mailee; Grill, Alex E.; Kovi, Ramesh C.; O’Sullivan, M. Gerard; Guttenplan, Joseph B.; Ho, Yen-Yi; Peterson, Lisa A.

2014-01-01

Furan is an abundant food and environmental contaminant that is a potent liver carcinogen in rodent models. To determine if furan is genotoxic in vivo, female B6C3F1 Big Blue transgenic mice were treated with 15 mg/kg bw furan by gavage 5 days a week for 6 weeks, or once weekly for 3 weeks. Liver cII trans-gene mutation-frequency and mutation spectra were determined. Furan did not increase the mutation frequency under either treatment condition. In the 6-week treatment regimen, there was a change in the cII transgene mutation-spectrum, with the fraction of GC to AT transitions significantly reduced. The only other significant change was an increase in GC to CG transversions; these represented a minor contribution to the overall mutation spectrum. A much larger furan-dependent shift was observed in the 3-week study. There was a significant increase in transversion mutations, predominantly GC to TA transversions as well as smaller non-significant changes in GC to CG and AT to TA transversions. To determine if these mutations were caused by cis-2-butene-1,4-dial (BDA), a reactive metabolite of furan, the mutagenic activity and the mutation spectrum of BDA was determined in vitro, in Big Blue mouse embryonic fibroblasts. This compound did not increase the cII gene mutation-frequency but caused a substantial increase in AT to CG transversions. This increase, however, lost statistical significance when adjusted for multiple comparisons. Together, these findings suggest that BDA may not be directly responsible for the in-vivo effects of furan on mutational spectra. Histopathological analysis of livers from furan-treated mice revealed that furan induced multifocal, hepatocellular necrosis admixed with reactive leukocytes and pigment-laden Kupffer cells, enhanced oval-cell hyperplasia, and increased hepatocyte mitoses, some of which were atypical. An indirect mechanism of genotoxicity is proposed in which chronic toxicity followed by inflammation and secondary cell proliferation triggers cancer development in furan-exposed rodents. PMID:25344163

[Clinical significance of peak body temperature, white blood cell count, and C-reactive protein level in febrile episodes among geriatric inpatients].

PubMed

Ikematsu, H; Nabeshima, A; Yamaga, S; Yamaji, K; Kakuda, K; Ueno, K; Hayashi, J; Shirai, T; Hara, H; Kashiwagi, S

1997-06-01

To investigate the clinical implication of peak body temperature, peripheral blood white blood cell (WBC) count, and serum C-reactive protein (CRP) level in febrile symptoms among geriatric hospitalized patients, they were analyzed in 968 febrile episodes obtained from 433 hospitalized patients in the referred hospital. Episodes of one day duration were most frequent (41.6%). WBC count was elevated over 8000/microliters in 475 episodes (49.1%) and CRP exceeded 1.0 mg/dl in 770 episodes (79.5%). Frequency of WBC elevation decreased and frequency of CRP elevation increased according to the time course. The mean value of CRP increased significantly according to the time course. The frequency of WBC count increase and CRP elevation and their averages correlated to the peak body temperature. The peak body temperature displayed the most striking correlation to the length of febrile episodes among three clinical indicators, peak body temperature, WBC count, and CRP level. These results indicate that the elevation of WBC count and/or CRP level is frequent in geriatric patients with febrile symptoms. Peak body temperature may serve as a clinical indicator of the severy of the febrile disease occurring in geriatric patients.

Recent trends in the frequency and duration of global floods

NASA Astrophysics Data System (ADS)

Najibi, Nasser; Devineni, Naresh

2018-06-01

Frequency and duration of floods are analyzed using the global flood database of the Dartmouth Flood Observatory (DFO) to explore evidence of trends during 1985-2015 at global and latitudinal scales. Three classes of flood duration (i.e., short: 1-7, moderate: 8-20, and long: 21 days and above) are also considered for this analysis. The nonparametric Mann-Kendall trend analysis is used to evaluate three hypotheses addressing potential monotonic trends in the frequency of flood, moments of duration, and frequency of specific flood duration types. We also evaluated if trends could be related to large-scale atmospheric teleconnections using a generalized linear model framework. Results show that flood frequency and the tails of the flood duration (long duration) have increased at both the global and the latitudinal scales. In the tropics, floods have increased 4-fold since the 2000s. This increase is 2.5-fold in the north midlatitudes. However, much of the trend in frequency and duration of the floods can be placed within the long-term climate variability context since the Atlantic Multidecadal Oscillation, North Atlantic Oscillation, and Pacific Decadal Oscillation were the main atmospheric teleconnections explaining this trend. There is no monotonic trend in the frequency of short-duration floods across all the global and latitudinal scales. There is a significant increasing trend in the annual median of flood durations globally and each latitudinal belt, and this trend is not related to these teleconnections. While the DFO data come with a certain level of epistemic uncertainty due to imprecision in the estimation of floods, overall, the analysis provides insights for understanding the frequency and persistence in hydrologic extremes and how they relate to changes in the climate, organization of global and local dynamical systems, and country-scale socioeconomic factors.

Understory response to varying fire frequencies after 20 years of prescribed burning in an upland oak forest

USGS Publications Warehouse

Burton, J.A.; Hallgren, S.W.; Fuhlendorf, S.D.; Leslie, David M.

2011-01-01

Ecosystems in the eastern United States that were shaped by fire over thousands of years of anthropogenic burning recently have been subjected to fire suppression resulting in significant changes in vegetation composition and structure and encroachment by invasive species. Renewed interest in use of fire to manage such ecosystems will require knowledge of effects of fire regime on vegetation. We studied the effects of one aspect of the fire regime, fire frequency, on biomass, cover and diversity of understory vegetation in upland oak forests prescribe-burned for 20 years at different frequencies ranging from zero to five fires per decade. Overstory canopy closure ranged from 88 to 96% and was not affected by fire frequency indicating high tolerance of large trees for even the most frequent burning. Understory species richness and cover was dominated by woody reproduction followed in descending order by forbs, C3 graminoids, C4 grasses, and legumes. Woody plant understory cover did not change with fire frequency and increased 30% from one to three years after a burn. Both forbs and C3 graminoids showed a linear increase in species richness and cover as fire frequency increased. In contrast, C4 grasses and legumes did not show a response to fire frequency. The reduction of litter by fire may have encouraged regeneration of herbaceous plants and helped explain the positive response of forbs and C3 graminoids to increasing fire frequency. Our results showed that herbaceous biomass, cover, and diversity can be managed with long-term prescribed fire under the closed canopy of upland oak forests. ?? 2011 Springer Science+Business Media B.V.

Sensorineural hearing loss in patients with chronic suppurative otitis media: Is there a significant correlation?

PubMed

Amali, Amin; Hosseinzadeh, Nima; Samadi, Shahram; Nasiri, Shirin; Zebardast, Jayran

2017-02-01

Hearing loss as a sequel of chronic suppurative otitis media (CSOM) is often conductive, but recent studies have found an additional sensorineural component in these patients, thus demonstrating inner ear damage. The aim of the study was to determine the association between CSOM and sensorineural hearing loss (SNHL) and to assess the influence of patient's age, duration of disease, and presence of cholesteatoma and ossicular erosion on the degree of SNHL. In a retrospective study, the medical records of 119 patients who underwent surgery was reviewed. Seventy patients met the inclusion criteria of unilateral otorrhea, normal contralateral ear on otoscopy, and age between 10-65 years with no history of head trauma or ear surgery or familial hearing loss. Bone conduction (BC) thresholds for affected and contralateral ear were measured at frequencies of 500, 1000, 2000, and 4000 Hz. Data analysis was performed using SPSS 13 with independent-samples t-test, Pearson correlation test, and two-tailed analysis. A p ≤ 0.05 was considered statistically significant. Significant higher BC thresholds were found in the affected ear than in the normal ear for each frequency (p < 0.001), which increased with increasing frequency (7.00 dB at the 500 Hz and 9.71 dB at the 4000 Hz). There was a significant correlation between age and degree of SNHL (r = 0.422, p < 0.001) but no significant correlation was in duration of the disease (r = 0.119, p > 0.05). There was no relationship between presence of cholesteatoma and ossicular erosion with SNHL (p > 0.05). These findings demonstrate that CSOM is associated with some degree of SNHL and cochlear damage, and higher frequencies are more affected. Aging can act as a precipitating factor in this pathological process.

Correlation between angiotensinogen gene and primary hypertension with cerebral infarction in the Li nationality of China.

PubMed

Wang, Tan; Chen, Zhi-Bin; Jin, Shui-Jing; Su, Qing-Jie

2007-09-01

To investigate the relationship of four single nucleotide polymorphism (SNP) haplotypes in the angiotensinogen (AGT) gene to the primary hypertension with or without cerebral infarction in the Li nationality of Hainan, China. Total 300 subjects were allocated into three different groups: Group 1, 100 patients who have primary hypertension; Group 2, 100 patients who have primary hypertension with cerebral infarction; and control group, 100 healthy individuals. The genotypes of all subjects were determined by PCR-sequencing to analyze the four polymorphisms at position -152 (G-A), -20 (A-C), -18 (C-T), and -6 (A-G) in the promoter region of AGT. The frequencies of CT genotype of AGT-18 and T allele in Group 1 (P = 0.003, P = 0.004) and Group 2 (P = 0.002, P = 0.002) were both significantly higher than in healthy controls. The frequency of G allele of AGT-6 was significantly higher in Group 2 than in the control group (P = 0.016), while there is no significant difference between Group 1 and the control. Haplotype analysis revealed that H6 haplotype frequency which included -20C and -6G was significantly increased in Group 2 (P = 0.003) compared with the control group, while H5 haplotype frequency which included -20C and -18T was significantly increased in Group 1 (P = 0.006) versus the control. The -20 (A-C) and -18 (C-T) of the AGT may play an important role in pathogenesis of primary hypertension; and -20 (A-C), -18 (C-T), and -6 (A-G) may be the genetic risk factors for the onset of primary hypertension with cerebral infarction in the Li nationality of Hainan, China.

Crustal attenuation characteristics in western Turkey

NASA Astrophysics Data System (ADS)

Kurtulmuş, Tevfik Özgür; Akyol, Nihal

2013-11-01

We analysed 1764 records produced by 322 micro- and moderate-size local earthquakes in western Turkey to estimate crustal attenuation characteristics in the frequency range of 1.0 ≤ f ≤ 10 Hz. In the first step, we obtained non-parametric attenuation functions and they show that seismic recordings of transverse and radial S waves exhibit different characteristics at short and long hypocentral distances. Applying a two-step inversion, we parametrized Q( f ) and geometrical spreading exponent b( f ) for the entire distance range between 10 and 200 km and then we estimated separately Q and b values for short (10-70 km) and large (120-200 km) distance ranges. We could not observe significant frequency dependencies of b for short distance range, whereas the significant frequency dependence of b was observed for large distances. Low Q0 values (˜60) with strong frequency dependence of Q (˜1.4) for short distances suggest that scattering might be an important factor contributing to the attenuation of body waves in the region, which could be associated to a high degree of fracturing, fluid filled cracks, young volcanism and geothermal activity in the crust. Weak Q frequency dependence and higher Q0 values for large distances manifest more homogenous medium because of increasing pressure and enhanced healing of cracks with increasing temperature and depth. Q anisotropy was also observed for large hypocentral distance ranges.

Swimming Speed of Larval Snail Does Not Correlate with Size and Ciliary Beat Frequency

PubMed Central

Chan, Kit Yu Karen; Jiang, Houshuo; Padilla, Dianna K.

2013-01-01

Many marine invertebrates have planktonic larvae with cilia used for both propulsion and capturing of food particles. Hence, changes in ciliary activity have implications for larval nutrition and ability to navigate the water column, which in turn affect survival and dispersal. Using high-speed high-resolution microvideography, we examined the relationship between swimming speed, velar arrangements, and ciliary beat frequency of freely swimming veliger larvae of the gastropod Crepidula fornicata over the course of larval development. Average swimming speed was greatest 6 days post hatching, suggesting a reduction in swimming speed towards settlement. At a given age, veliger larvae have highly variable speeds (0.8–4 body lengths s−1) that are independent of shell size. Contrary to the hypothesis that an increase in ciliary beat frequency increases work done, and therefore speed, there was no significant correlation between swimming speed and ciliary beat frequency. Instead, there are significant correlations between swimming speed and visible area of the velar lobe, and distance between centroids of velum and larval shell. These observations suggest an alternative hypothesis that, instead of modifying ciliary beat frequency, larval C. fornicata modify swimming through adjustment of velum extension or orientation. The ability to adjust velum position could influence particle capture efficiency and fluid disturbance and help promote survival in the plankton. PMID:24367554

Effect of reciprocating agitation thermal processing (RA-TP) on quality of canned tomato (Solanum lycopersicum) puree.

PubMed

Pratap Singh, Anubhav; Singh, Anika; Ramaswamy, Hosahalli S

2017-06-01

Reciprocating agitation thermal processing (RA-TP) is a recent innovation in the field of canning for obtaining high-quality canned food. The objective of this study was to compare RA-TP processing with conventional non-agitated (still) processing with respect to the impact on quality (color, antioxidant capacity, total phenols, carotenoid and lycopene contents) of canned tomato (Solanum lycopersicum) puree. Owing to a 63-81% reduction in process times as compared with still processing, tomato puree with a brighter red color (closer to fresh) was obtained during RA-TP. At 3 Hz reciprocation frequency, the loss of antioxidant, lycopene and carotenoid contents could be reduced to 34, 8 and 8% respectively as compared with 96, 41 and 52% respectively during still processing. In fact, the phenolic content for RA-TP at 3 Hz was 5% higher than in fresh puree. Quality retention generally increased with an increase in frequency, although the differences were less significant at higher reciprocation frequencies (between 2 and 3 Hz). Research findings indicate that RA-TP can be effective to obtain thermally processed foods with high-quality attribute retention. It can also be concluded that a very high reciprocation frequency (>3 Hz) is not necessarily needed and significant quality improvement can be obtained at lower frequencies (∼2 Hz). © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

High sensitivity of p-modes near the acoustic cutoff frequency to solar model parameters

NASA Technical Reports Server (NTRS)

Guenther, D. B.

1991-01-01

The p-mode frequencies of low l have been calculated for solar models with initial helium mass fraction varying from Y = 0.2753-0.2875. The differences in frequency of the p-modes in the frequency range, 2500-4500 microHz, do not exceed 1-5 microHz among the models. But in the vicinity of the acoustic cutoff frequency, near 5000 microHz the p-mode frequency differences are enhanced by a factor of 4. The enhanced sensitivity of p-modes near the acoustic cutoff frequency was further tested by calculating and comparing p-mode frequencies of low l for two solar models one incorporating the Eddington T-tau relation and the other the Krishna Swamy T-tau relation. Again, it is found that p-modes with frequencies near the acoustic cutoff frequency show a significant increase in sensitivity to the different T-tau relations, compared to lower frequency p-modes. It is noted that frequencies above the acoustic cutoff frequency are complex, hence, cannot be modeled by the adiabatic pulsation code (assumes real eigenfrequencies) used in these calculations.

Increased first and second pulse harmonics in Tai Chi Chuan practitioners.

PubMed

Lu, Wan-An; Chen, Yung-Sheng; Kuo, Cheng-Deng

2016-02-29

Tai Chi Chuan (TCC) is known to be a good calisthenics for people. This study examined the relationship between pulse harmonics and autonomic nervous modulation in TCC practitioners. Power spectral measures of right pulse wave and heart rate variability (HRV) measures were compared between TCC practitioners and control subjects. Correlation analyses between pulse harmonics and HRV measures were performed using linear regression analysis. At baseline, the total power of pulse (TPp), powers of all individual pulse harmonics, normalized power of the 1(st) harmonics (nPh1) of TCC practitioners were greater, while the normalized power of the 4(th) pulse harmonics (nPh4) of TCC practitioners was smaller, than those of the controls. Similarly, the baseline standard deviation (SD(RR)), coefficient of variation (CV(RR)), and normalized high-frequency power (nHFP) of RR intervals were smaller, while the normalized very low-frequency power (nVLFP) and low-/high- frequency power ratio (LHR) were larger in the TCC practitioners. The TCC age correlated significantly and negatively with nPh1, and nearly significantly and negatively with nPh2 in the TCC practitioners. Thirty min after TCC exercise, the percentage changes in mRRI, SDRR, TP, VLFP were decreased, while the percentage changes in HR, ULFP, nLFP, and Ph2 were increased, relative to the controls. Correlation analysis shows that the %Ph2 correlates significantly and negatively with %mRRI and significantly and positively with %HR. The TCC practitioners had increased baseline total power of pulse and the 1(st) and 2(nd) pulse harmonics, and decreased power of the 4(th) pulse harmonics, along with decreased vagal modulation and increased sympathetic modulation. After TCC exercise, the power of the 2(nd) harmonics of TCC practitioners was increased which might be related to the increase in HR due to decreased vascular resistance after TCC exercise.

Intravesical TRPV4 blockade reduces repeated variate stress-induced bladder dysfunction by increasing bladder capacity and decreasing voiding frequency in male rats

PubMed Central

Merrill, Liana

2014-01-01

Individuals with functional lower urinary tract disorders including interstitial cystitis (IC)/bladder pain syndrome (BPS) and overactive bladder (OAB) often report symptom (e.g., urinary frequency) worsening due to stress. One member of the transient receptor potential ion channel vanilloid family, TRPV4, has recently been implicated in urinary bladder dysfunction disorders including OAB and IC/BPS. These studies address the role of TRPV4 in stress-induced bladder dysfunction using an animal model of stress in male rats. To induce stress, rats were exposed to 7 days of repeated variate stress (RVS). Quantitative PCR data demonstrated significant (P ≤ 0.01) increases in TRPV4 transcript levels in urothelium but not detrusor smooth muscle. Western blot analyses of split urinary bladders (i.e., urothelium and detrusor) showed significant (P ≤ 0.01) increases in TRPV4 protein expression levels in urothelial tissues but not detrusor smooth muscle. We previously showed that RVS produces bladder dysfunction characterized by decreased bladder capacity and increased voiding frequency. The functional role of TRPV4 in RVS-induced bladder dysfunction was evaluated using continuous, open outlet intravesical infusion of saline in conjunction with administration of a TRPV4 agonist, GSK1016790A (3 μM), a TRPV4 antagonist, HC067047 (1 μM), or vehicle (0.1% DMSO in saline) in control and RVS-treated rats. Bladder capacity, void volume, and intercontraction interval significantly decreased following intravesical instillation of GSK1016790A in control rats and significantly (P ≤ 0.01) increased following administration of HC067047 in RVS-treated rats. These results demonstrate increased TRPV4 expression in the urothelium following RVS and that TRPV4 blockade ameliorates RVS-induced bladder dysfunction consistent with the role of TRPV4 as a promising target for bladder function disorders. PMID:24965792

Enhanced response to the induction of sister chromatid exchange by gamma radiation in neurofibromatosis

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

Hafez, M.; Abd el-Nabi, S.M.; el-Wehedi, G.

The study included 8 unrelated patients with neurofibromatosis, and 10 unrelated normal and healthy persons as controls. Whole blood samples were divided into plastic T flasks and exposed at room temperature to gamma rays. The radiation dose was 36 rad/minute, and the doses delivered were 0, 75, 150 and 300 rad. The lymphocytes were cultured in (RPMI) 1640 tissue culture medium and autologous serum (20%). Phytohemagglutinin and bromodeoxyuridine (Brdu) (10 microM) were added at initiation of culture and harvesting was done 64 to 68 hours after culture initiation. Slides were coded, differential staining was done, and sister chromatid exchanges (SCEs)more » and aberrations (gaps, breaks, dicentrics, fragments and minutes) were counted. In the controls no significant increase in frequency of SCE has been found (P greater than 0.5). In the patients, the frequencies significantly increased with the increase of dose of irradiation (P less than 0.001). Furthermore, after irradiation, the incidence of gaps, breaks, and dicentrics were significantly increased in patients compared with controls. Moreover, the incidence increased with the increase in the dose of radiation. The results are discussed with a conclusion that the results add to the indication of a genetic predisposition to develop cancer in neurofibromatosis patients.« less

Interspecific Neighbor Interactions Promote the Positive Diversity-Productivity Relationship in Experimental Grassland Communities

PubMed Central

Zhang, Yuhua; Wang, Yongfan; Yu, Shixiao

2014-01-01

Because the frequency of heterospecific interactions inevitably increases with species richness in a community, biodiversity effects must be expressed by such interactions. However, little is understood how heterospecific interactions affect ecosystem productivity because rarely are biodiversity ecosystem functioning experiments spatially explicitly manipulated. To test the effect of heterospecific interactions on productivity, direct evidence of heterospecific neighborhood interaction is needed. In this study we conducted experiments with a detailed spatial design to investigate whether and how heterospecific neighborhood interactions promote primary productivity in a grassland community. The results showed that increasing the heterospecific: conspecific contact ratio significantly increased productivity. We found there was a significant difference in the variation in plant height between monoculture and mixture communities, suggesting that height-asymmetric competition for light plays a central role in promoting productivity. Heterospecific interactions make tall plants grow taller and short plants become smaller in mixtures compared to monocultures, thereby increasing the efficiency of light interception and utilization. Overyielding in the mixture communities arises from the fact that the loss in the growth of short plants is compensated by the increased growth of tall plants. The positive correlation between species richness and primary production was strengthened by increasing the frequency of heterospecific interactions. We conclude that species richness significantly promotes primary ecosystem production through heterospecific neighborhood interactions. PMID:25350670

Interspecific neighbor interactions promote the positive diversity-productivity relationship in experimental grassland communities.

PubMed

Zhang, Yuhua; Wang, Yongfan; Yu, Shixiao

2014-01-01

Because the frequency of heterospecific interactions inevitably increases with species richness in a community, biodiversity effects must be expressed by such interactions. However, little is understood how heterospecific interactions affect ecosystem productivity because rarely are biodiversity ecosystem functioning experiments spatially explicitly manipulated. To test the effect of heterospecific interactions on productivity, direct evidence of heterospecific neighborhood interaction is needed. In this study we conducted experiments with a detailed spatial design to investigate whether and how heterospecific neighborhood interactions promote primary productivity in a grassland community. The results showed that increasing the heterospecific: conspecific contact ratio significantly increased productivity. We found there was a significant difference in the variation in plant height between monoculture and mixture communities, suggesting that height-asymmetric competition for light plays a central role in promoting productivity. Heterospecific interactions make tall plants grow taller and short plants become smaller in mixtures compared to monocultures, thereby increasing the efficiency of light interception and utilization. Overyielding in the mixture communities arises from the fact that the loss in the growth of short plants is compensated by the increased growth of tall plants. The positive correlation between species richness and primary production was strengthened by increasing the frequency of heterospecific interactions. We conclude that species richness significantly promotes primary ecosystem production through heterospecific neighborhood interactions.

Nitric oxide signaling pathways involved in the inhibition of spontaneous activity in the guinea pig prostate.

PubMed

Dey, Anupa; Lang, Richard J; Exintaris, Betty

2012-06-01

We investigated nitric oxide mediated inhibition of spontaneous activity recorded in young and aging guinea pig prostates. Conventional intracellular microelectrode and tension recording techniques were used. The nitric oxide donor sodium nitroprusside (10 μM) abolished spontaneous contractions and slow wave activity in 5 young and 5 aging prostates. Upon adding the nitric oxide synthase inhibitor L-NAME (10 μM) the frequency of spontaneous contractile and electrical activity was significantly increased in each age group. This increase was significantly larger in 4 to 8 preparations of younger vs aging prostates (about 40% to 50% vs about 10% to 20%, 2-way ANOVA p<0.01). Other measured parameters, including the duration, amplitude and membrane potential of spontaneous electrical and contractile activity, were not altered from control values. The guanylate cyclase inhibitor ODQ (10 μM) significantly increased the frequency of spontaneous activity by 10% to 30% in 6 young guinea pig prostates (Student paired t test p<0.05). However, it had no effect on aging prostates. The cGMP analogue 8-Br-GMP (1 μM) and the PDE5 inhibitor dipyridamole (1 μM) significantly decreased the frequency of contractile activity by about 70% in 4 to 9 young and older prostates (Student paired t test p<0.05). The decrease in the response to L-NAME in spontaneous contractile and slow wave activity in aging prostate tissue compared to that in young prostates suggests that with age there is a decrease in nitric oxide production. This may further explain the increase in prostatic smooth muscle tone observed in age related prostate specific conditions, such as benign prostatic hyperplasia. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

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

Uryupin, S A; Frolov, A A

We have developed a theory of generation of low-frequency radiation and surface waves under the pondermotive action of a femtosecond laser pulse irradiating a conductor along the normal and focused by a cylindrical lens. It is shown that for the chosen focusing method and specified values of laser pulse duration and flux density it is possible to significantly increase the total energy of both surface waves and low-frequency radiation. (terahertz radiation)

A growing importance of large fires in conterminous United States during 1984-2012

Treesearch

Jia Yang; Hanqin Tian; Bo Tao; Wei Ren; Shufen Pan; Yongqiang Liu; Yuhang Wang

2015-01-01

Fire frequency, extent, and size exhibit a strong linkage with climate conditions and play a vital role in the climate system. Previous studies have shown that the frequency of large fires in the western United States increased significantly since the mid-1980s due to climate warming and frequent droughts. However, less work has been conducted to examine burned area...

Cytogenetic biomonitoring of primary school children exposed to air pollutants: micronuclei analysis of buccal epithelial cells.

PubMed

Demircigil, Gonca Çakmak; Erdem, Onur; Gaga, Eftade O; Altuğ, Hicran; Demirel, Gülçin; Özden, Özlem; Arı, Akif; Örnektekin, Sermin; Döğeroğlu, Tuncay; van Doorn, Wim; Burgaz, Sema

2014-01-01

There is an increasing attempt in the world to determine the exposures of children to environmental chemicals. To analyze the genotoxic effect of air pollution, micronucleus (MN) assay was carried out in buccal epithelial cells (BECs) of children living in an urban city of Turkey. Children from two schools at urban-traffic and suburban sites were investigated in summer and winter seasons for the determination of BEC-MN frequency (per mille) and frequency of BEC with MN (per mille). The same children were also recruited for lung function measurements within a MATRA project ("Together Towards Clean Air in Eskisehir and Iskenderun") Measured NO2 and SO2 concentrations did not exceed the European Union (EU) limit levels either in urban-traffic or suburban regions. Higher O3 concentrations were measured in the suburban site especially in the summer period. Particulate matter (PM2.5 and PM10) levels which did not differ statistically between two regions were above the EU limits in general. Although BEC-MN frequencies of children living in the suburban sites were higher in general, the difference between two regions was not significant either in the summer or winter periods. BEC-MN frequencies of the urban-traffic children were found to be significantly higher in summer period (mean ± SD, 2.68 ± 1.99) when compared to winter period (1.64 ± 1.59; p = 0.004). On the other hand, no seasonality was observed for the suburban children. Similar results have been obtained in the BEC frequency with MN in our study. In summer, BEC-MN frequencies were significantly increased with the decrease in pulmonary function levels based on forced expiratory flow between 25 and 75% of vital capacity (FEF25-75%) levels (p < 0.05). As a conclusion, children living in urban-traffic and suburban areas in the city of Eskişehir exhibited similar genotoxicity. Seasonal variation in genotoxicity may be interpreted as relatively high ozone levels and increasing time spent at outdoors in the summer.

Time frequency power profile of QRS complex obtained with wavelet transform in spontaneously hypertensive rats.

PubMed

Takano, Nami K; Tsutsumi, Takeshi; Suzuki, Hiroshi; Okamoto, Yoshiwo; Nakajima, Toshiaki

2012-02-01

We evaluated whether frequency analysis could detect the development of interstitial fibrosis in rats. SHR/Izm and age-matched WKY/Izm were used. Limb lead II electrocardiograms were recorded. Continuous wavelet transform (CWT) was applied for the time-frequency analysis. The integrated time-frequency power (ITFP) between QRS complexes was measured and compared between groups. The ITFP at low-frequency bands (≤125Hz) was significantly higher in SHR/Izm. The percent change of ITFP showed the different patterns between groups. Prominent interstitial fibrosis with an increase in TIMP-1 mRNA expression was also observed in SHR/Izm. These results were partly reproduced in a computer simulation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Studies on the positive inotropic effect of phenylephrine: a comparison with isoprenaline.

PubMed

Ledda, F; Marchetti, P; Mugelli, A

1975-05-01

1. The effects of phenylephrine and isoprenaline on the isometric contraction of guinea-pig ventricle were compared over the whole range of their respective dose-response curves. 2. In preparations driven at 2.5 Hz the increase in contractile force induced by either isoprenaline of phenylephrine was linearly correlated to an increase in maximum velocity of force development. The relaxation time was shortened by isoprenaline but not by phenylephrine. 3. The negative inotropic effect induced by delta [N-(3,4-dimethoxyphenethyl)-N-methyl-amino]-alpha-(3,4,5-trimethoxyphenyl)alpha-isopropylvaleronitrile hydrochloride (D(600)) was reversed by isoprenaline, but little influenced by phenylephrine. 4. The study of the interval-force relationship shows that the increase in contractile force induced by phenylephrine (3 X 10(-5) M) was relatively greater at low frequencies of stimulation, and that the maximum effect was reached at the frequency of 1 Hz. 5. The positive inotropic effect of phenylephrine (10-4 M) was significantly higher at a frequency of 1 Hz than at 2.5 Hz; the effect of isoprenaline (3 x 10-8 M) was not significantly different at the two driving frequencies. 6. In preparations driven at 1 Hz the inotropic effect of the lower concentrations of phenylephrine was due to an increase in the time to peak tension without any change of the maximum velocity of force development; however an increase of this parameter became evident only after higher concentrations of the amine (10-5 M or more), associated with a progressive shortening of the time to peak. 7. A correlation between mechanical and electrophysiological effects of phenylephrine is attempted; the suggestion is advanced that the prolongation of the action potential and of the active state duration may be an important factor in the inotropic effect of phenylephrine.

Sympathomimetic Effects of Acute E-Cigarette Use: Role of Nicotine and Non-Nicotine Constituents.

PubMed

Moheimani, Roya S; Bhetraratana, May; Peters, Kacey M; Yang, Benjamin K; Yin, Fen; Gornbein, Jeffrey; Araujo, Jesus A; Middlekauff, Holly R

2017-09-20

Chronic electronic (e) cigarette users have increased resting cardiac sympathetic nerve activity and increased susceptibility to oxidative stress. The purpose of the present study is to determine the role of nicotine versus non-nicotine constituents in e-cigarette emissions in causing these pathologies in otherwise healthy humans. Thirty-three healthy volunteers who were not current e-cigarette or tobacco cigarette smokers were studied. On different days, each participant used an e-cigarette with nicotine, an e-cigarette without nicotine, or a sham control. Cardiac sympathetic nerve activity was determined by heart rate variability, and susceptibility to oxidative stress was determined by plasma paraoxonase activity. Following exposure to the e-cigarette with nicotine, but not to the e-cigarette without nicotine or the sham control, there was a significant and marked shift in cardiac sympathovagal balance towards sympathetic predominance. The decrease in high-frequency component and the increases in the low-frequency component and the low-frequency to high-frequency ratio were significantly greater following exposure to the e-cigarette with nicotine compared with exposure to the e-cigarette without nicotine or to sham control. Oxidative stress, as estimated by plasma paraoxonase, did not increase following any of the 3 exposures. The acute sympathomimetic effect of e-cigarettes is attributable to the inhaled nicotine, not to non-nicotine constituents in e-cigarette aerosol, recapitulating the same heart rate variability pattern associated with increased cardiac risk in multiple populations with and without known cardiac disease. Evidence of oxidative stress, as estimated by plasma paraoxonase activity, was not uncovered following acute e-cigarette exposure. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Ozone Inhalation Leads to a Dose-Dependent Increase of Cytogenetic Damage in Human Lymphocytes

PubMed Central

Holland, Nina; Davé, Veronica; Venkat, Subha; Wong, Hofer; Donde, Aneesh; Balmes, John R; Arjomandi, Mehrdad

2014-01-01

Ozone is an important constituent of ambient air pollution and represents a major public health concern. Oxidative injury due to ozone inhalation causes the generation of reactive oxygen species and can be genotoxic. To determine whether ozone exposure causes genetic damage in peripheral blood lymphocytes, we employed a well-validated cytokinesis-block micronucleus Cytome assay. Frequencies of micronuclei (MN) and nucleoplasmic bridges (NB) were used as indicators of cytogenetic damage. Samples were obtained from 22 non-smoking healthy subjects immediately before and 24-hr after controlled 4-hr exposures to filtered air, 100 ppb, and 200 ppb ozone while exercising in a repeated-measure study design. Inhalation of ozone at different exposure levels was associated with a significant dose-dependent increase in MN frequency (P < 0.0001) and in the number of cells with more than 1 MN per cell (P < 0.0005). Inhalation of ozone also caused an increase in the number of apoptotic cells (P = 0.002). Airway neutrophilia was associated with an increase in MN frequency (P = 0.033) independent of the direct effects of ozone exposure (P < 0.0001). We also observed significant increases in both MN and NB frequencies after exercise in filtered air, suggesting that physical activity is also an important inducer of oxidative stress. These results corroborate our previous findings that cytogenetic damage is associated with ozone exposure, and show that damage is dose-dependent. Further study of ozone-induced cytogenetic damage in airway epithelial cells could provide evidence for the role of oxidative injury in lung carcinogenesis, and help to address the potential public health implications of exposures to oxidant environments. PMID:25451016

Traveling-Wave Tube Efficiency Enhancement

NASA Technical Reports Server (NTRS)

Dayton, James A., Jr.

2011-01-01

Traveling-wave tubes (TWT's) are used to amplify microwave communication signals on virtually all NASA and commercial spacecraft. Because TWT's are a primary power user, increasing their power efficiency is important for reducing spacecraft weight and cost. NASA Glenn Research Center has played a major role in increasing TWT efficiency over the last thirty years. In particular, two types of efficiency optimization algorithms have been developed for coupled-cavity TWT's. The first is the phase-adjusted taper which was used to increase the RF power from 420 to 1000 watts and the RF efficiency from 9.6% to 22.6% for a Ka-band (29.5 GHz) TWT. This was a record efficiency at this frequency level. The second is an optimization algorithm based on simulated annealing. This improved algorithm is more general and can be used to optimize efficiency over a frequency bandwidth and to provide a robust design for very high frequency TWT's in which dimensional tolerance variations are significant.

The impact of a 2 X CO2 climate on lightning-caused fires

NASA Technical Reports Server (NTRS)

Price, Colin; Rind, David

1994-01-01

Future climate change could have significant repercussions for lightning-caused wildfires. Two empirical fire models are presented relating the frequency of lightning fires and the area burned by these fires to the effective precipitation and the frequency of thunderstorm activity. One model deals with the seasonal variations in lightning fires, while the second model deals with the interannual variations of lightning fires. These fire models are then used with the Goddard Institute for Space Studies General Circulation Model to investigate possible changes in fire frequency and area burned in a 2 X CO2 climate. In the United States, the annual mean number of lightning fires increases by 44%, while the area burned increases by 78%. On a global scale, the largest increase in lightning fires can be expected in untouched tropical ecosystems where few natural fires occur today.

Wave propagation in fluid-conveying viscoelastic single-walled carbon nanotubes with surface and nonlocal effects

NASA Astrophysics Data System (ADS)

Zhen, Ya-Xin

2017-02-01

In this paper, the transverse wave propagation in fluid-conveying viscoelastic single-walled carbon nanotubes is investigated based on nonlocal elasticity theory with consideration of surface effect. The governing equation is formulated utilizing nonlocal Euler-Bernoulli beam theory and Kelvin-Voigt model. Explicit wave dispersion relation is developed and wave phase velocities and frequencies are obtained. The effect of the fluid flow velocity, structural damping, surface effect, small scale effects and tube diameter on the wave propagation properties are discussed with different wave numbers. The wave frequency increases with the increase of fluid flow velocity, but decreases with the increases of tube diameter and wave number. The effect of surface elasticity and residual surface tension is more significant for small wave number and tube diameter. For larger values of wave number and nonlocal parameters, the real part of frequency ratio raises.

Audio-vocal responses of vocal fundamental frequency and formant during sustained vowel vocalizations in different noises.

PubMed

Lee, Shao-Hsuan; Hsiao, Tzu-Yu; Lee, Guo-She

2015-06-01

Sustained vocalizations of vowels [a], [i], and syllable [mə] were collected in twenty normal-hearing individuals. On vocalizations, five conditions of different audio-vocal feedback were introduced separately to the speakers including no masking, wearing supra-aural headphones only, speech-noise masking, high-pass noise masking, and broad-band-noise masking. Power spectral analysis of vocal fundamental frequency (F0) was used to evaluate the modulations of F0 and linear-predictive-coding was used to acquire first two formants. The results showed that while the formant frequencies were not significantly shifted, low-frequency modulations (<3 Hz) of F0 significantly increased with reduced audio-vocal feedback across speech sounds and were significantly correlated with auditory awareness of speakers' own voices. For sustained speech production, the motor speech controls on F0 may depend on a feedback mechanism while articulation should rely more on a feedforward mechanism. Power spectral analysis of F0 might be applied to evaluate audio-vocal control for various hearing and neurological disorders in the future. Copyright © 2015 Elsevier B.V. All rights reserved.

Efficacy and Safety of Daikenchuto for Constipation and Dose-Dependent Differences in Clinical Effects.

PubMed

Hirose, Tatsuya; Shinoda, Yasutaka; Kuroda, Ayaka; Yoshida, Aya; Mitsuoka, Machiko; Mori, Kouki; Kawachi, Yuki; Moriya, Akihiro; Tanaka, Kouji; Takeda, Atsuko; Yoshimura, Tomoaki; Sugiyama, Tadashi

2018-01-01

Daikenchuto (DKT) is a Kampo medicine used for the treatment of constipation. In this study, we evaluated the effectiveness of DKT against constipation. Thirty-three patients administered DKT for constipation were selected and divided into low-dose (7.5 g DKT; n = 22) and high-dose (15 g DKT; n = 11) groups. We retrospectively evaluated weekly defaecation frequency, side effects, and clinical laboratory data. Median defaecation frequencies after DKT administration (5, 5.5, 5, and 8 for the first, second, third, and fourth weeks, resp.) were significantly higher than that before DKT administration (2) in all 33 cases ( P < 0.01). One case (3%) of watery stool, one case of loose stools (3%), and no cases of abdominal pain (0%) were observed. Median defaecation frequencies in the high-dose group (7 and 9) were significantly higher than those in the low-dose group (4 and 3) in the first ( P = 0.0133) and second ( P = 0.0101) weeks, respectively. There was no significant change in clinical laboratory values. We suggest that DKT increases defaecation frequency and is safe for treating constipation.

Using social cognitive theory to explain discretionary, "leisure-time" physical exercise among high school students.

PubMed

Winters, Eric R; Petosa, Rick L; Charlton, Thomas E

2003-06-01

To examine whether knowledge of high school students' actions of self-regulation, and perceptions of self-efficacy to overcome exercise barriers, social situation, and outcome expectation will predict non-school related moderate and vigorous physical exercise. High school students enrolled in introductory Physical Education courses completed questionnaires that targeted selected Social Cognitive Theory variables. They also self-reported their typical "leisure-time" exercise participation using a standardized questionnaire. Bivariate correlation statistic and hierarchical regression were conducted on reports of moderate and vigorous exercise frequency. Each predictor variable was significantly associated with measures of moderate and vigorous exercise frequency. All predictor variables were significant in the final regression model used to explain vigorous exercise. After controlling for the effects of gender, the psychosocial variables explained 29% of variance in vigorous exercise frequency. Three of four predictor variables were significant in the final regression equation used to explain moderate exercise. The final regression equation accounted for 11% of variance in moderate exercise frequency. Professionals who attempt to increase the prevalence of physical exercise through educational methods should focus on the psychosocial variables utilized in this study.

Wastewater microalgal production, nutrient removal and physiological adaptation in response to changes in mixing frequency.

PubMed

Sutherland, Donna L; Turnbull, Matthew H; Broady, Paul A; Craggs, Rupert J

2014-09-15

Laminar flows are a common problem in high rate algal ponds (HRAP) due to their long channels and gentle mixing by a single paddlewheel. Sustained laminar flows may modify the amount of light microalgal cells are exposed to, increase the boundary layer between the cell and the environment and increase settling out of cells onto the pond bottom. To date, there has been little focus on the effects of the time between mixing events (frequency of mixing) on the performance of microalgae in wastewater treatment HRAPs. This paper investigates the performance of three morphologically distinct microalgae in wastewater treatment high rate algal mesocosms operated at four different mixing frequencies (continuous, mixed every 45 min, mixed every 90 min and no mixing). Microalgal performance was measured in terms of biomass concentration, nutrient removal efficiency, light utilisation and photosynthetic performance. Microalgal biomass increased significantly with increasing mixing frequency for the two colonial species but did not differ for the single celled species. All three species were more efficient at NH4-N uptake as the frequency of mixing increased. Increased frequency of mixing supported larger colonies with improved harvest-ability by gravity but at the expense of efficient light absorption and maximum rate of photosynthesis. However, maximum quantum yield was highest in the continuously mixed cultures due to higher efficiency of photosynthesis under light limited conditions. Based on these results, higher microalgal productivity, improved wastewater treatment and better gravity based harvest-ability can be achieved with the inclusion of more mixing points and reduced laminar flows in full-scale HRAP. Copyright © 2014 Elsevier Ltd. All rights reserved.

High vs. Low Frequency Stimulation Effects on Fine Motor Control in Chronic Hemiplegia: A Pilot Study

PubMed Central

Doucet, Barbara M.; Griffin, Lisa

2014-01-01

Introduction The optimal parameters of neuromuscular electrical stimulation (NMES) for recovery of hand function following stroke are not known. This clinical pilot study examined whether higher or lower frequencies are more effective for improving fine motor control of the hand in a chronic post-stroke population. Methods A one-month, 4x/week in-home regimen of either a high frequency (40Hz) or low frequency (20Hz) NMES program was applied to the hemiplegic thenar muscles of 16 persons with chronic stroke. Participants were identified a priori as having a low level of function (LF) or a high level of function (HF). Outcome measures of strength, dexterity, and endurance were measured before and after participation in the regimen. Results LF subjects showed no significant changes with either the high or the low frequency NMES regimen. HF subjects showed significant changes in strength, dexterity and endurance. Within this group, higher frequencies of stimulation yielded strength gains and increased motor activation; lower frequencies impacted dexterity and endurance. Conclusions The results suggest that higher frequencies of stimulation could be more effective in improving strength and motor activation properties and that lower frequencies may impact coordination and endurance changes; results also indicate that persons with a higher functional level of recovery may respond more favorably to NMES regimens, but further study with larger patient groups is warranted. PMID:23893829

Frequencies of inaudible high-frequency sounds differentially affect brain activity: positive and negative hypersonic effects.

PubMed

Fukushima, Ariko; Yagi, Reiko; Kawai, Norie; Honda, Manabu; Nishina, Emi; Oohashi, Tsutomu

2014-01-01

The hypersonic effect is a phenomenon in which sounds containing significant quantities of non-stationary high-frequency components (HFCs) above the human audible range (max. 20 kHz) activate the midbrain and diencephalon and evoke various physiological, psychological and behavioral responses. Yet important issues remain unverified, especially the relationship existing between the frequency of HFCs and the emergence of the hypersonic effect. In this study, to investigate the relationship between the hypersonic effect and HFC frequencies, we divided an HFC (above 16 kHz) of recorded gamelan music into 12 band components and applied them to subjects along with an audible component (below 16 kHz) to observe changes in the alpha2 frequency component (10-13 Hz) of spontaneous EEGs measured from centro-parieto-occipital regions (Alpha-2 EEG), which we previously reported as an index of the hypersonic effect. Our results showed reciprocal directional changes in Alpha-2 EEGs depending on the frequency of the HFCs presented with audible low-frequency component (LFC). When an HFC above approximately 32 kHz was applied, Alpha-2 EEG increased significantly compared to when only audible sound was applied (positive hypersonic effect), while, when an HFC below approximately 32 kHz was applied, the Alpha-2 EEG decreased (negative hypersonic effect). These findings suggest that the emergence of the hypersonic effect depends on the frequencies of inaudible HFC.

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.

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

Multifaceted roles for low-frequency oscillations in bottom-up and top-down processing during navigation and memory.

PubMed

Ekstrom, Arne D; Watrous, Andrew J

2014-01-15

A prominent and replicated finding is the correlation between running speed and increases in low-frequency oscillatory activity in the hippocampal local field potential. A more recent finding concerns low-frequency oscillations that increase in coherence between the hippocampus and neocortical brain areas such as prefrontal cortex during memory-related behaviors (i.e., remembering the correct location to visit). In this review, we tie together movement-related and memory-related low-frequency oscillations in the rodent with similar findings in humans. We argue that although movement-related low-frequency oscillations, in particular, may have slightly different characteristics in humans than rodents, placing important constraints on our thinking about this issue, both phenomena have similar functional foundations. We review four prominent theoretical models that provide partially conflicting accounts of movement-related low-frequency oscillations. We attempt to tie together these theoretical proposals, and existing data in rodents and humans, with memory-related low-frequency oscillations. We propose that movement-related low-frequency oscillations and memory-related low-frequency oscillatory activity, both of which show significant coherence with oscillations in other brain regions, represent different facets of "spectral fingerprints," or different resonant frequencies within the same brain networks underlying different cognitive processes. Together, movement-related and memory-related low-frequency oscillatory coupling may be linked by their distinct contributions to bottom-up, sensorimotor driven processing and top-down, controlled processing characterizing aspects of memory encoding and retrieval. Copyright © 2013. Published by Elsevier Inc.

Multifaceted roles for low-frequency oscillations in bottom-up and top-down processing during navigation and memory

PubMed Central

Ekstrom, Arne D.; Watrous, Andrew J.

2014-01-01

A prominent and replicated finding is the correlation between running speed and increases in low-frequency oscillatory activity in the hippocampal local field potential. A more recent finding concerns low-frequency oscillations that increase in coherence between the hippocampus and neocortical brain areas such as prefrontal cortex during memory-related behaviors (i.e., remembering the correct arm to explore). In this review, we tie together movement-related and memory-related low-frequency oscillations in the rodent with similar findings in humans. We argue that although movement-related low-frequency oscillations, in particular, may have slightly different characteristics in humans than rodents, placing important constraints on our thinking about this issue, both phenomena have similar functional foundations. We review four prominent theoretical models that provide partially conflicting accounts of movement-related low-frequency oscillations. We attempt to tie together these theoretical proposals, and existing data in rodents and humans, with memory-related low-frequency oscillations. We propose that movement-related low-frequency oscillations and memory-related low-frequency oscillatory activity, both of which show significant coherence with oscillations in other brain regions, represent different facets of “spectral fingerprints,” or different resonant frequencies within the same brain networks underlying different cognitive processes. Together, movement-related and memory-related low-frequency oscillatory coupling may be linked by their distinct contributions to bottom-up, sensorimotor driven processing and top-down, controlled processing characterizing aspects of memory encoding and retrieval. PMID:23792985

Concurrent sympathetic activation and vagal withdrawal in hyperthyroidism: Evidence from detrended fluctuation analysis of heart rate variability

NASA Astrophysics Data System (ADS)

Chen, Jin-Long; Shiau, Yuo-Hsien; Tseng, Yin-Jiun; Chiu, Hung-Wen; Hsiao, Tzu-Chien; Wessel, Niels; Kurths, Jürgen; Chu, Woei-Chyn

2010-05-01

Despite many previous studies on the association between hyperthyroidism and the hyperadrenergic state, controversies still exist. Detrended fluctuation analysis (DFA) is a well recognized method in the nonlinear analysis of heart rate variability (HRV), and it has physiological significance related to the autonomic nervous system. In particular, an increased short-term scaling exponent α1 calculated from DFA is associated with both increased sympathetic activity and decreased vagal activity. No study has investigated the DFA of HRV in hyperthyroidism. This study was designed to assess the sympathovagal balance in hyperthyroidism. We performed the DFA along with the linear analysis of HRV in 36 hyperthyroid Graves’ disease patients (32 females and 4 males; age 30 ± 1 years, means ± SE) and 36 normal controls matched by sex, age and body mass index. Compared with the normal controls, the hyperthyroid patients revealed a significant increase ( P<0.001) in α1 (hyperthyroid 1.28±0.04 versus control 0.91±0.02), long-term scaling exponent α2 (1.05±0.02 versus 0.90±0.01), overall scaling exponent α (1.11±0.02 versus 0.89±0.01), low frequency power in normalized units (LF%) and the ratio of low frequency power to high frequency power (LF/HF); and a significant decrease ( P<0.001) in the standard deviation of the R-R intervals (SDNN) and high frequency power (HF). In conclusion, hyperthyroidism is characterized by concurrent sympathetic activation and vagal withdrawal. This sympathovagal imbalance state in hyperthyroidism helps to explain the higher prevalence of atrial fibrillation and exercise intolerance among hyperthyroid patients.

Processed food consumption and risk of esophageal squamous cell carcinoma: A case-control study in a high risk area.

PubMed

Song, Qingkun; Wang, Xiaorong; Yu, Ignatius Tak-sun; Huang, Chengyu; Zhou, Xiaoqiao; Li, Jun; Wang, Dong

2012-11-01

This study was conducted to investigate the association between consumption of processed foods and esophageal cancer risk. A population-based case-control study was designed. For the present study, 254 patients with esophageal squamous cell carcinoma with pathological diagnoses were selected from Yanting during 2008 and 2010 and 254 community-based controls were selected from the same area, individually matched with cases by age and sex. Data on demographic, lifestyle and dietary factors were collected using food frequency questionnaires. A conditional logistic regression model was used to estimate the odds ratio (OR) with adjustments for potential confounders. Compared to the frequency of <1 time/week, the intake frequency of >3 times/week of preserved vegetables had a significant association with esophageal cancer (OR = 5.01, 95% confidence interval [CI] 2.07, 12.17). In stratified analyses, the OR of increasing intake of preserved vegetables for esophageal cancer were 2.02 in men (95% CI 1.18, 3.48), 3.15 in women (95% CI 1.28, 7.75), 2.41 (95% CI 1.45 4.01) in the persons <65 years old and 1.28 (95% CI 0.35, 4.65) in persons ≥65 years old. Consumption of pickled vegetables was not associated significantly with esophageal cancer risk. Intake of salted meat with a frequency of ≥1 time/week meant that the OR increased to 2.57 (95%CI 1.02, 6.43), but no significant trend or association in subgroup analysis was observed. Preserved vegetable consumption was associated with increased risk of esophageal cancer, while no association was found with pickled vegetables. © 2012 Japanese Cancer Association.

Trabecular bone adaptation to low-magnitude high-frequency loading in microgravity.

PubMed

Torcasio, Antonia; Jähn, Katharina; Van Guyse, Maarten; Spaepen, Pieter; Tami, Andrea E; Vander Sloten, Jos; Stoddart, Martin J; van Lenthe, G Harry

2014-01-01

Exposure to microgravity causes loss of lower body bone mass in some astronauts. Low-magnitude high-frequency loading can stimulate bone formation on earth. Here we hypothesized that low-magnitude high-frequency loading will also stimulate bone formation under microgravity conditions. Two groups of six bovine cancellous bone explants were cultured at microgravity on a Russian Foton-M3 spacecraft and were either loaded dynamically using a sinusoidal curve or experienced only a static load. Comparable reference groups were investigated at normal gravity. Bone structure was assessed by histology, and mechanical competence was quantified using μCT and FE modelling; bone remodelling was assessed by fluorescent labelling and secreted bone turnover markers. Statistical analyses on morphometric parameters and apparent stiffness did not reveal significant differences between the treatment groups. The release of bone formation marker from the groups cultured at normal gravity increased significantly from the first to the second week of the experiment by 90.4% and 82.5% in response to static and dynamic loading, respectively. Bone resorption markers decreased significantly for the groups cultured at microgravity by 7.5% and 8.0% in response to static and dynamic loading, respectively. We found low strain magnitudes to drive bone turnover when applied at high frequency, and this to be valid at normal as well as at microgravity. In conclusion, we found the effect of mechanical loading on trabecular bone to be regulated mainly by an increase of bone formation at normal gravity and by a decrease in bone resorption at microgravity. Additional studies with extended experimental time and increased samples number appear necessary for a further understanding of the anabolic potential of dynamic loading on bone quality and mechanical competence.

Pulse Wave Amplitude Drops during Sleep are Reliable Surrogate Markers of Changes in Cortical Activity

PubMed Central

Delessert, Alexandre; Espa, Fabrice; Rossetti, Andrea; Lavigne, Gilles; Tafti, Mehdi; Heinzer, Raphael

2010-01-01

Background: During sleep, sudden drops in pulse wave amplitude (PWA) measured by pulse oximetry are commonly associated with simultaneous arousals and are thought to result from autonomic vasoconstriction. In the present study, we determine whether PWA drops were associated with changes in cortical activity as determined by EEG spectral analysis. Methods: A 20% decrease in PWA was chosen as a minimum for a drop. A total of 1085 PWA drops from 10 consecutive sleep recordings were analyzed. EEG spectral analysis was performed over 5 consecutive epochs of 5 seconds: 2 before, 1 during, and 2 after the PWA drop. EEG spectral analysis was performed over delta, theta, alpha, sigma, and beta frequency bands. Within each frequency band, power density was compared across the five 5-sec epochs. Presence or absence of visually scored EEG arousals were adjudicated by an investigator blinded to the PWA signal and considered associated with PWA drop if concomitant. Results: A significant increase in EEG power density in all EEG frequency bands was found during PWA drops (P < 0.001) compared to before and after drop. Even in the absence of visually scored arousals, PWA drops were associated with a significant increase in EEG power density (P < 0.001) in most frequency bands. Conclusions: Drops in PWA are associated with a significant increase in EEG power density, suggesting that these events can be used as a surrogate for changes in cortical activity during sleep. This approach may prove of value in scoring respiratory events on limited-channel (type III) portable monitors. Citation: Delessert A; Espa F; Rossetti A; Lavigne G; Tafti M; Heinzer R. Pulse wave amplitude drops during sleep are reliable surrogate markers of changes in cortical activity. SLEEP 2010;33(12):1687-1692. PMID:21120131

Beta-fibrinogen allele frequencies in Peruvian Quechua, a high-altitude native population.

PubMed

Rupert, J L; Devine, D V; Monsalve, M V; Hochachka, P W

1999-06-01

Elevated hematocrits, which are found in many high-altitude populations, increase the oxygen-carrying capacity of blood and may represent an adaptation to hypoxic environments. However, as high hematocrit increases blood viscosity, which in turn is associated with hypertension and heart disease, it may be advantageous for high-altitude populations to limit other factors that contribute to increased blood viscosity. One such factor is the plasma concentration of the coagulation protein fibrinogen. Several common polymorphisms in the beta-fibrinogen gene have been identified that affect fibrinogen concentrations. We determined the allele frequencies of three of these polymorphisms (G/A-455(HaeIII), C/T-148(HindIII), and G/A+448(MnlI)) in sample groups drawn from three populations: Quechua-speaking natives living at over 3,200 m in the Peruvian Andes, North American natives (Na-Dene) from coastal British Columbia, and Caucasian North Americans. The frequencies of the alleles previously shown to be associated with increased fibrinogen levels were so low in the Quechuas that their presence could be accounted for solely by genetic admixture with Caucasians. Frequencies in the Na-Dene, a Native American group unrelated to the Quechua, were not significantly different from those in Caucasians.

Weather and childbirth: a further search for relationships.

PubMed

Driscoll, D M

1995-03-01

Previous attempts to find relationships between weather and parturition (childbirth) and its onset (the beginning of labor pains) have revealed, firstly, limited but statistically significant relationships between weather conditions much colder than the day before, with high winds and low pressure, and increased onsets; and secondly, increased numbers of childbirths during periods of atmospheric pressure rise (highly statistically significant). To test these findings, this study examined weather data coincident childbirth data from a hospital at Bryan-College Station, Texas (for a period of 30 cool months from 1987 to 1992). Tests for (1) days of cold fronts, (2) a day before and a day after the cold front, (3) days with large temperature increases, and (4) decreases from the day before revealed no relationship with mean daily rate of onset. Cold days with high winds and low pressure had significantly fewer onsets, a result that is the opposite of previous findings. The postulated relationship between periods of pressure rise and increased birth frequency was negative, i.e., significantly fewer births occurred at those times--again, the opposite of the apparent occurrence in an earlier study. The coincidence of diurnal variations in both atmospheric pressure and frequency of childbirths, was shown to account for fairly strong negative associations between the two variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Single versus triple daily activation of the distractor: no significant effects of frequency of distraction on bone regenerate quantity and architecture.

PubMed

Djasim, Urville Mardijanto; Wolvius, Eppo Bonne; Van Neck, Johan Wilhelm; Van Wamel, Annemieke; Weinans, Harrie; Van Der Wal, Karel George Hendrik

2008-04-01

To study the effect of two different frequencies of distraction on the quantity and architecture of bone regenerate using micro-computed tomography, and to determine whether radiographic and ultrasonographic bone-fill scores provide reliable predictive value for the amount of new bone in the distraction area. Twenty-six skeletally mature rabbits underwent three full days of latency, after which midface distraction was started. Low-frequency group (n=12): a distraction rate of 0.9 mm/d achieved by one daily activation for 11 days to create a 10mm distraction gap. High-frequency group (n=12): idem, but three daily activations were used instead of one. Control group (n=2) underwent no distraction. After 21 days of consolidation, bone-fill in the distraction area was assessed by means of ultrasonography and radiography. Micro-computed tomography was used to quantify new bone formation and bone architecture. Relative bone volume (BV/TV) showed a tendency towards a difference (P=0.09) between the low and high-frequency groups. No significant differences were found for bone architecture. No significant correlation between BV/TV values and bone-fill scores was found. An increase in rhythm from one to three activations daily does not create significantly more bone. Bone-fill score values provided no reliable predictive value for the amount of new bone formation.

Multi-frequency localization of aberrant brain activity in autism spectrum disorder.

PubMed

Xiang, Jing; Korostenskaja, Milena; Molloy, Cynthia; deGrauw, Xinyao; Leiken, Kimberly; Gilman, Carley; Meinzen-Derr, Jareen; Fujiwara, Hisako; Rose, Douglas F; Mitchell, Terry; Murray, Donna S

2016-01-01

The abnormality of intrinsic brain activity in autism spectrum disorders (ASDs) is still inconclusive. Contradictory results have been found pointing towards hyper-activity or hypo-activity in various brain regions. The present research aims to investigate the spatial and spectral signatures of aberrant brain activity in an unprecedented frequency range of 1-2884 Hz at source levels in ASD using newly developed methods. Seven ASD subjects and age- and gender-matched controls were studied using a high-sampling rate magnetoencephalography (MEG) system. Brain activity in delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12-30 Hz), low gamma (30-55 Hz), high gamma (65-90 Hz), ripples (90-200 Hz), high-frequency oscillations (HFOs, 200-1000 Hz), and very high-frequency oscillations (VHFOs, 1000-2884 Hz) was volumetrically localized and measured using wavelet and beamforming. In comparison to controls, ASD subjects had significantly higher odds of alpha activity (8-12 Hz) in the sensorimotor cortex (mu rhythm), and generally high-frequency activity (90-2884 Hz) in the frontal cortex. The source power of HFOs (200-1000 Hz) in the frontal cortex in ASD was significantly elevated as compared with controls. The results suggest that ASD has significantly altered intrinsic brain activity in both low- and high-frequency ranges. Increased intrinsic high-frequency activity in the frontal cortex may play a key role in ASD. Copyright © 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Health risks of gold miners: a synoptic review

USGS Publications Warehouse

Eisler, R.

2003-01-01

Health problems of gold miners who worked underground include decreased life expectancy; increased frequency of cancer of the trachea, bronchus, lung, stomach, and liver; increased frequency of pulmonary tuberculosis (PTB), silicosis, and pleural diseases; increased frequency of insect-borne diseases, such as malaria and dengue fever; noise-induced hearing loss; increased prevalence of certain bacterial and viral diseases; and diseases of the blood, skin, and musculoskeletal system. These problems are briefly documented in gold miners from Australia, North America, South America, and Africa. In general, HIV infection or excessive alcohol and tobacco consumption tended to exacerbate existing health problems. Miners who used elemental mercury to amalgamate and extract gold were heavily contaminated with mercury. Among individuals exposed occupationally, concentrations of mercury in their air, fish diet, hair, urine, blood, and other tissues significantly exceeded all criteria proposed by various national and international regulatory agencies for protection of human health. However, large-scale epidemiological evidence of severe mercury-associated health problems in this cohort was not demonstrable.

Effect of fractionation on treatment outcome in local dual-frequency sonication and Dox-encapsulated nanomicelles.

PubMed

Hasanzadeh, Hadi; Mokhtari-Dizaji, Manijhe; Bathaie, S Zahra; Hassan, Zuhair M

2013-10-01

The goal of this study was to localize drug release from nanomicelles using dual-frequency sonication at low levels of acoustic intensity. In this study, the antitumor effect of simultaneous dual-frequency sonication (28 kHz and 3 MHz) at low levels of acoustic intensity in combination with doxorubicin and micellar doxorubicin injection was assessed in a spontaneous model of breast adenocarcinoma in female Balb/c mice. Sixty-three tumor-bearing mice were randomly grouped into control, sham, dual-frequency sonication, doxorubicin injection with and without dual-frequency sonication, and micellar doxorubicin injection with and without dual-frequency sonication groups. The results of volume change relative to initial volume showed that in the micellar doxorubicin injection with sonication group, this parameter was significantly different from that of the control, sham, sonication, and doxorubicin injection groups (P < 0.05). In addition, the volume began to increase on the 15th day after the start of treatment, which is a good indication to repeat treatment; therefore, another group received an extra treatment on day 15. The animal life span in the micellar doxorubicin with sonication and repeated treatment groups was significantly higher than that in all the other experimental groups except for the micellar doxorubicin injection group (P < 0.05). It was concluded that dual-frequency sonication with micellar doxorubicin injection extends the life span relative to doxorubicin injection or dual-frequency sonication alone, and that repeating this treatment on day 15 decreases the rate of tumor growth significantly.

Use of positive and negative words in scientific PubMed abstracts between 1974 and 2014: retrospective analysis.

PubMed

Vinkers, Christiaan H; Tijdink, Joeri K; Otte, Willem M

2015-12-14

To investigate whether language used in science abstracts can skew towards the use of strikingly positive and negative words over time. Retrospective analysis of all scientific abstracts in PubMed between 1974 and 2014. The yearly frequencies of positive, negative, and neutral words (25 preselected words in each category), plus 100 randomly selected words were normalised for the total number of abstracts. Subanalyses included pattern quantification of individual words, specificity for selected high impact journals, and comparison between author affiliations within or outside countries with English as the official majority language. Frequency patterns were compared with 4% of all books ever printed and digitised by use of Google Books Ngram Viewer. Frequencies of positive and negative words in abstracts compared with frequencies of words with a neutral and random connotation, expressed as relative change since 1980. The absolute frequency of positive words increased from 2.0% (1974-80) to 17.5% (2014), a relative increase of 880% over four decades. All 25 individual positive words contributed to the increase, particularly the words "robust," "novel," "innovative," and "unprecedented," which increased in relative frequency up to 15,000%. Comparable but less pronounced results were obtained when restricting the analysis to selected journals with high impact factors. Authors affiliated to an institute in a non-English speaking country used significantly more positive words. Negative word frequencies increased from 1.3% (1974-80) to 3.2% (2014), a relative increase of 257%. Over the same time period, no apparent increase was found in neutral or random word use, or in the frequency of positive word use in published books. Our lexicographic analysis indicates that scientific abstracts are currently written with more positive and negative words, and provides an insight into the evolution of scientific writing. Apparently scientists look on the bright side of research results. But whether this perception fits reality should be questioned. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Progress toward Brazilian cesium fountain second generation

NASA Astrophysics Data System (ADS)

Bueno, Caio; Rodriguez Salas, Andrés; Torres Müller, Stella; Bagnato, Vanderlei Salvador; Varela Magalhães, Daniel

2018-03-01

The operation of a Cesium fountain primary frequency standard is strongly influenced by the characteristics of two important subsystems. The first is a stable frequency reference and the second is the frequency-transfer system. A stable standard frequency reference is key factor for experiments that require high accuracy and precision. The frequency stability of this reference has a significant impact on the procedures for evaluating certain systematic biases in frequency standards. This paper presents the second generation of the Brazilian Cesium Fountain (Br-CsF) through the opto-mechanical assembly and vacuum chamber to trap atoms. We used a squared section glass profile to build the region where the atoms are trapped and colled by magneto-optical technique. The opto-mechanical system was reduced to increase stability and robustness. This newest Atomic Fountain is essential to contribute with time and frequency development in metrology systems.

Quantitative Ultrasound Comparison of MAT and 4T1 Mammary Tumors in Mice and Rats Across Multiple Imaging Systems.

PubMed

Wirtzfeld, Lauren A; Ghoshal, Goutam; Rosado-Mendez, Ivan M; Nam, Kibo; Park, Yeonjoo; Pawlicki, Alexander D; Miller, Rita J; Simpson, Douglas G; Zagzebski, James A; Oelze, Michael L; Hall, Timothy J; O'Brien, William D

2015-08-01

Quantitative ultrasound estimates such as the frequency-dependent backscatter coefficient (BSC) have the potential to enhance noninvasive tissue characterization and to identify tumors better than traditional B-mode imaging. Thus, investigating system independence of BSC estimates from multiple imaging platforms is important for assessing their capabilities to detect tissue differences. Mouse and rat mammary tumor models, 4T1 and MAT, respectively, were used in a comparative experiment using 3 imaging systems (Siemens, Ultrasonix, and VisualSonics) with 5 different transducers covering a range of ultrasonic frequencies. Functional analysis of variance of the MAT and 4T1 BSC-versus-frequency curves revealed statistically significant differences between the two tumor types. Variations also were found among results from different transducers, attributable to frequency range effects. At 3 to 8 MHz, tumor BSC functions using different systems showed no differences between tumor type, but at 10 to 20 MHz, there were differences between 4T1 and MAT tumors. Fitting an average spline model to the combined BSC estimates (3-22 MHz) demonstrated that the BSC differences between tumors increased with increasing frequency, with the greatest separation above 15 MHz. Confining the analysis to larger tumors resulted in better discrimination over a wider bandwidth. Confining the comparison to higher ultrasonic frequencies or larger tumor sizes allowed for separation of BSC-versus-frequency curves from 4T1 and MAT tumors. These constraints ensure that a greater fraction of the backscattered signals originated from within the tumor, thus demonstrating that statistically significant tumor differences were detected. © 2015 by the American Institute of Ultrasound in Medicine.

Conservation threats due to human-caused increases in fire frequency in Mediterranean-climate ecosystems.

PubMed

Syphard, Alexandra D; Radeloff, Volker C; Hawbaker, Todd J; Stewart, Susan I

2009-06-01

Periodic wildfire is an important natural process in Mediterranean-climate ecosystems, but increasing fire recurrence threatens the fragile ecology of these regions. Because most fires are human-caused, we investigated how human population patterns affect fire frequency. Prior research in California suggests the relationship between population density and fire frequency is not linear. There are few human ignitions in areas with low population density, so fire frequency is low. As population density increases, human ignitions and fire frequency also increase, but beyond a density threshold, the relationship becomes negative as fuels become sparser and fire suppression resources are concentrated. We tested whether this hypothesis also applies to the other Mediterranean-climate ecosystems of the world. We used global satellite databases of population, fire activity, and land cover to evaluate the spatial relationship between humans and fire in the world's five Mediterranean-climate ecosystems. Both the mean and median population densities were consistently and substantially higher in areas with than without fire, but fire again peaked at intermediate population densities, which suggests that the spatial relationship is complex and nonlinear. Some land-cover types burned more frequently than expected, but no systematic differences were observed across the five regions. The consistent association between higher population densities and fire suggests that regardless of differences between land-cover types, natural fire regimes, or overall population, the presence of people in Mediterranean-climate regions strongly affects the frequency of fires; thus, population growth in areas now sparsely settled presents a conservation concern. Considering the sensitivity of plant species to repeated burning and the global conservation significance of Mediterranean-climate ecosystems, conservation planning needs to consider the human influence on fire frequency. Fine-scale spatial analysis of relationships between people and fire may help identify areas where increases in fire frequency will threaten ecologically valuable areas. ©2009 Society for Conservation Biology.

Two Point Space-Time Correlation of Density Fluctuations Measured in High Velocity Free Jets

NASA Technical Reports Server (NTRS)

Panda, Jayanta

2006-01-01

Two-point space-time correlations of air density fluctuations in unheated, fully-expanded free jets at Mach numbers M(sub j) = 0.95, 1.4, and 1.8 were measured using a Rayleigh scattering based diagnostic technique. The molecular scattered light from two small probe volumes of 1.03 mm length was measured for a completely non-intrusive means of determining the turbulent density fluctuations. The time series of density fluctuations were analyzed to estimate the integral length scale L in a moving frame of reference and the convective Mach number M(sub c) at different narrow Strouhal frequency (St) bands. It was observed that M(sub c) and the normalized moving frame length scale L*St/D, where D is the jet diameter, increased with Strouhal frequency before leveling off at the highest resolved frequency. Significant differences were observed between data obtained from the lip shear layer and the centerline of the jet. The wave number frequency transform of the correlation data demonstrated progressive increase in the radiative part of turbulence fluctuations with increasing jet Mach number.

Effects of Ti doping on the dielectric properties of HfO{sub 2} nanoparticles

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

Pokhriyal, S.; Biswas, S., E-mail: drsomnathbiswas@gmail.com

2016-05-06

We report the effects of Ti doping on the dielectric properties of HfO{sub 2} [Hf{sub 1-x}Ti{sub x}O{sub 2} (x = 0.2-0.8)] nanoparticles at room temperature. The Hf{sub 1-x}Ti{sub x}O{sub 2} nanoparticles were synthesized by a wet chemical process. The structural and morphological properties of the derived samples were analyzed with X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and high resolution transmission electron microscopy (HRTEM). Impedance analysis was performed in pelletized samples in the frequency range of 1 MHz to 1 GHz. The obtained results were analyzed in correlation with microstructure and doping concentration in the derived samples. The averagemore » size of the Hf{sub 1-x}Ti{sub x}O{sub 2} nanoparticles is typically in the range of 4-8 nm depending on the processing temperature. The Hf{sub 1−x}Ti{sub x}O{sub 2} nanoparticles show reduction in crystallinity with the increase in Ti doping. The dielectric constants of the derived samples decrease with the increase in frequency. The ac-conductivity in the samples increases with the increase in frequency irrespective of Ti concentration and shows significant drop with the increase in Ti concentration at all frequencies.« less

High density terahertz frequency comb produced by coherent synchrotron radiation

PubMed Central

Tammaro, S.; Pirali, O.; Roy, P.; Lampin, J.-F.; Ducournau, G.; Cuisset, A.; Hindle, F.; Mouret, G.

2015-01-01

Frequency combs have enabled significant progress in frequency metrology and high-resolution spectroscopy extending the achievable resolution while increasing the signal-to-noise ratio. In its coherent mode, synchrotron radiation is accepted to provide an intense terahertz continuum covering a wide spectral range from about 0.1 to 1 THz. Using a dedicated heterodyne receiver, we reveal the purely discrete nature of this emission. A phase relationship between the light pulses leads to a powerful frequency comb spanning over one decade in frequency. The comb has a mode spacing of 846 kHz, a linewidth of about 200 Hz, a fractional precision of about 2 × 10−10 and no frequency offset. The unprecedented potential of the comb for high-resolution spectroscopy is demonstrated by the accurate determination of pure rotation transitions of acetonitrile. PMID:26190043

Auditory frequency generalization in the goldfish (Carassius auratus)1

PubMed Central

Fay, Richard R.

1970-01-01

Auditory frequency generalization in the goldfish was studied at five points within the best hearing range through the use of classical respiratory conditioning. Each experimental group received single-stimulus conditioning sessions at one of five stimulus frequencies (100, 200, 400, 800, and 1600 Hz), and were subsequently tested for generalization at eight neighboring frequencies. All stimuli were presented 30 db above absolute threshold. Significant generalization decrements were found for all subjects. For the subjects conditioned in the range between 100 and 800 Hz, a nearly complete failure to generalize was found at one octave above and below the training frequency. The subjects conditioned at 1600 Hz produced relatively more flat gradients between 900 and 2000 Hz. The widths of the generalization gradients, expressed in Hz, increased as a power function of frequency with a slope greater than one. PMID:16811481

Ontogeny and control of the heart rate power spectrum in the last third of gestation in fetal sheep.

PubMed

Koome, Miriam E; Bennet, Laura; Booth, Lindsea C; Davidson, Joanne O; Wassink, Guido; Gunn, Alistair Jan

2014-01-01

Power spectral analysis of fetal heart rate variability has been proposed to provide a non-invasive estimate of autonomic balance. However, there are few systematic data before birth. We therefore examined developmental changes in the frequency power spectrum at very low (0-0.04 Hz), low (0.04-0.15 Hz) and high frequencies (0.15-0.4 Hz), as well as the ratio of low- to high-frequency power (LF/HF), in chronically catheterized, healthy fetal sheep at 0.6 (n = 8), 0.7 (n = 7) and 0.8 gestational age (ga; n = 11). In a second study, 0.8 ga fetuses received either atropine (4.8 mg bolus, then 4.8 mg h(-1) for 30 min, n = 6) or 6-hydroxydopamine (20 mg ml(-1) at 2.5 ml h(-1) for 3 h; n = 9). Data were analysed by sleep state, defined by low-voltage-high-frequency (LV) or high-voltage-low-frequency (HV) EEG. Total spectral power increased with gestational age (P < 0.05), while LF/HF decreased from 0.6 to 0.7 ga. At 0.8 ga, heart rate and LF/HF were significantly higher during HV than LV sleep (P < 0.05). Consistent with this, although total spectral power was not significantly greater during HV sleep, there was a significant interaction between sleep state and frequency band (P = 0.02). Both atropine (P = 0.05) and 6-hydroxydopamine (P < 0.05) were associated with an overall reduction in spectral power but no significant effect on the LF/HF ratio. This study does not support substantial, consistent differences between the frequencies of sympathetic and parasympathetic activity in late-gestation fetal sheep.

Children's toothbrushing frequency: the influence of parents' rationale for brushing, habits and family routines.

PubMed

Trubey, Rob J; Moore, Simon C; Chestnutt, Ivor G

2015-01-01

To assess the relationship between parental and family factors and children's toothbrushing frequency at different times of day. A cross-sectional questionnaire survey of predominantly low-socio-economic status parents of children aged 3-6 years (n = 296) in South Wales, UK. Data were collected on the child's weekly toothbrushing frequency (morning and evening), the parents' rationale for brushing their child's teeth in the morning and evening, the strength of a parent's habit for brushing a child's teeth in the morning and evening, and the extent to which the family's daily routines were stable from day to day. Socio-demographic details were also collected. Reported weekly brushing frequency was significantly (p < 0.001) higher in the morning (mean ± SD: 6.57 ± 1.37) than the evening (mean ± SD: 5.99 ± 2.15). Parents had significantly (p < 0.001) more interest in the cosmetic benefits of toothbrushing in the morning compared to the evening. Multivariate analysis showed that an increasing focus on the cosmetic benefits of toothbrushing was associated with significantly (p < 0.05) less weekly brushing in the evening. The extent to which brushing a child's teeth was 'habitual' was significantly (p < 0.001) associated with weekly toothbrushing frequency at both times of day. Parents' rationale for brushing their children's teeth can vary at both an individual level and at different times of day. Understanding these variations is important in designing interventions to improve brushing frequency for at-risk children. The results also demonstrate habituation as being an important factor in understanding toothbrushing frequency. Further research is required to understand the mechanisms involved in habit formation and maintenance with children's oral hygiene behaviour.

Crossing the Threshold From Porn Use to Porn Problem: Frequency and Modality of Porn Use as Predictors of Sexually Coercive Behaviors.

PubMed

Marshall, Ethan A; Miller, Holly A; Bouffard, Jeff A

2017-11-01

According to recent statistics, as many as one in five female college students are victims of sexual assault during their college career. To combat what has been called the "Campus Rape Crisis," researchers have attempted to understand what variables are associated with sexually coercive behaviors in college males. Although investigators have found support for the relationship between pornography consumption and sexually coercive behavior, researchers typically operationalize pornography use in terms of frequency of use. Furthermore, frequency of use has been assessed vaguely and inconsistently. The current study offered a more concrete assessment of frequency of use and an additional variable not yet included for pornography use: number of modalities. Beyond examining the relationship between pornography use and sexual coercion likelihood, the current study was the first to use pornography variables in a threshold analysis to test whether there is a cut point that is predictive of sexual coercion likelihood. Analyses were conducted with a sample of 463 college males. Results indicated that both pornography use variables were significantly related to a higher likelihood of sexually coercive behaviors. When both frequency of use and number of modalities were included in the model, modalities were significant and frequency was not. In addition, significant thresholds for both pornography variables that predicted sexual coercion likelihood were identified. These results imply that factors other than frequency of use, such as number of modalities, may be more important for the prediction of sexual coercive behaviors. Furthermore, threshold analyses revealed the most significant increase in risk occurred between one modality and two, indicating that it is not pornography use in general that is related to sexual coercion likelihood, but rather, specific aspects of pornography use.

[Factors Associated with the Use of Protective Gear among Adults during Recreational Sledging].

PubMed

Ruedl, G; Pocecco, E; Kopp, M; Raas, C; Blauth, M; Brucker, P U; Burtscher, M

2015-09-01

Recreational sledging (tobogganing) is a very popular winter sport in the Alps. Therefore, injury prevention through the usage of protective gear seems important. Therefore, the aim of this study was to evaluate factors associated with the use of protective gear among adults during recreational sledging. Adult recreational sledgers were interviewed during the winter seasons 2012/13 and 2013/14 at six sledging tracks in Austria on demographics, skill level, sledging frequency, risk taking behaviour, sitting alone or with another person on the sledge, previous sledging-related injuries, and use of protective gear, respectively. Interviews were conducted on all days of the week. A total of 1968 adult sledgers (49.4 % females) with a mean age of 37.1 ± 14.4 years participated in this study. A (ski) helmet, sun or snow goggles, a back protector, and wrist guards were used by 42.3 %, 71.0 %, 5.9 %, 2.6 % of sledgers, respectively. Helmet use was significantly higher with increasing age and increasing skill level as well as when sitting alone compared to sitting together with another person. Females, Austrians, persons sitting alone on the sledge, a higher frequency of sledging and a higher skill level were significantly associated with an increasing use of goggles. A back protector was significantly more often worn by younger people, more risky sledgers, and persons with a previous sledging-related injury. Wrist guards were significantly more often used by persons with a previous sledging-related injury. During recreational sledging, the factors age, sex, nationality, skill level, sitting alone compared to sitting together with another person on the sledge, sledging frequency, and injury experience were associated with the frequencies of usage of different types of protective gear. These factors should be considered when implementing preventive measures for recreational sledging. © Georg Thieme Verlag KG Stuttgart · New York.

Heart rate and blood pressure variabilities in salt-sensitive hypertension.

PubMed

Piccirillo, G; Bucca, C; Durante, M; Santagada, E; Munizzi, M R; Cacciafesta, M; Marigliano, V

1996-12-01

In salt-sensitive hypertension, a high sodium intake causes plasma catecholamines to rise and pulmonary baroreceptor plasticity to fall. In salt-sensitive and salt-resistant hypertensive subjects during low and high sodium intakes, we studied autonomic nervous system activity by power spectral analysis of heart rate and arterial pressure variabilities and baroreceptor sensitivity. In all subjects, high sodium intake significantly enhanced the low-frequency power of heart rate and arterial pressures at rest and after sympathetic stress. It also increased heart rate and arterial pressure variabilities. During high sodium intake, salt-sensitive hypertensive subjects had significantly higher low-frequency powers of systolic arterial pressure (7.5 mm Hg2, P < .05) and of heart rate at rest (59.2 +/- 2.4 normalized units [NU], P < .001) than salt-resistant subjects (6.6 +/- 0.3 mm Hg2, 55.0 +/- 3.2 NU) and normotensive control subjects (5.1 +/- 0.5 mm Hg2, 41.6 +/- 2.9 NU). In salt-sensitive subjects, low sodium intake significantly reduced low-frequency normalized units (P < .001) and the ratio of low- to high-power frequency (P < .001). High-sodium intake significantly increased baroreflex sensitivity in control subjects (from 10.0 +/- 0.7 to 17.5 +/- 0.7 ms/mm Hg, P < .001) and salt-resistant subjects (from 6.9 +/- 0.7 to 13.9 +/- 0.9, P < .05) but not in salt-sensitive subjects (7.4 +/- 0.3 to 7.9 +/- 0.4). In conclusion, a high sodium intake markedly enhances cardiac sympathetic activity in salt-sensitive and salt-resistant hypertension. In contrast, although reduced sodium intake lowers arterial pressure and sympathetic activity, it does so only in salt-sensitive subjects. Hence, in salt-resistant subjects, neither arterial pressure nor sympathetic activity depends on salt intake. During a high sodium intake in normotensive subjects and salt-resistant hypertensive subjects, increased sympathetic activity is probably compensated by enhanced baroreflex sensitivity.

Microwave monolithic filter and phase shifter using magnetic nanostructures

NASA Astrophysics Data System (ADS)

Aslam, Shehreen; Khanna, Manoj; Veenugopal, Veerakumar; Kuanr, Bijoy K.

2018-05-01

Monolithic Microwave Integrated Circuit (MMIC) have major impact on the development of microwave communication technology. Transition metal based ferromagnetic nano-wired (FMNWs) substrate are of special interest in order to fabricate these MMIC devices. Their saturation magnetization is comparatively higher than ferrites which makes them suitable for high frequency (>10 ˜ 40 GHz) operation at zero or a small applied magnetic field. The CoFeB nanowires in anodic alumina templates were synthesized using three-electrode electro-deposition system. After electro-deposition, 1μm thick Cu layer was sputtered on the top surface of FMNW substrate and lithography was done to design microstrip lines. These microstrip transmission lines were tested for band-stop filters and phase shifters based on ferromagnetic resonance (FMR) over a wide applied magnetic field (H) range. It was observed that attenuation and frequency increase with the increase of magnetic field (upto 5.3 kOe). For phase shifter, the influence of magnetic material was studied for two frequency regions: (i) below FMR and (ii) above FMR. These two frequency regions were suitable for many practical device applications as the insertion loss was very less in these regions in comparison to resonance frequency regions. In the high frequency region (at 35 GHz), the optimal differential phase shift increased significantly to ˜ 250 deg/cm and around low frequency region (at 24 GHz), the optimal differential phase shift is ˜175 deg/cm at the highest field (H) value.

Influence of Temple Headache Frequency on Physical Functioning and Emotional Functioning in Subjects with Temporomandibular Disorder Pain

PubMed Central

List, Thomas; John, Mike T.; Ohrbach, Richard; Schiffman, Eric L.; Truelove, Edmond L.; Anderson, Gary C.

2015-01-01

Aims To investigate the relationship of headache frequency with patient-reported physical functioning and emotional functioning in temporomandibular disorder (TMD) subjects with concurrent temple headache. Methods The Research Diagnostic Criteria for TMD (RDC/TMD) Validation Project identified, as a subset of 614 TMD cases and 91 controls (n = 705), 309 subjects with concurrent TMD pain diagnoses (RDC/TMD) and temple headache. The temple headaches were subdivided into infrequent, frequent, and chronic headache according to the International Classification of Headache Disorders, second edition (ICHD–II). Study variables included self-report measures of physical functioning (Jaw Function Limitation Scale [JFLS], Graded Chronic Pain Scale [GCPS], Short Form–12 [SF–12]) and emotional functioning (depression and anxiety as measured by the Symptom Checklist–90R/SCL–90R). Differences among the three headache subgroups were characterized by increasing headache frequency. The relationship between ordered headache frequency and physical as well as emotional functioning was analyzed using linear regression and trend tests for proportions. Results Physical functioning, as assessed with the JFLS (P < .001), SF-12 (P < .001), and GCPS (P < .001), was significantly associated with increased headache frequency. Emotional functioning, reflected in depression and anxiety, was also associated with increased frequency of headache (both P < .001). Conclusion Headache frequency was substantially correlated with reduced physical functioning and emotional functioning in subjects with TMD and concurrent temple headaches. A secondary finding was that headache was precipitated by jaw activities more often in subjects with more frequent temple headaches. PMID:22558607

Effect of frequency on the uniformity of symmetrical RF CCP discharges

NASA Astrophysics Data System (ADS)

Liu, Yue; Booth, Jean-Paul; Chabert, Pascal

2018-05-01

A 2D Cartesian electrostatic particle-in-cell/Monte Carlo collision (PIC/MCC) model presented previously (Liu et al 2018 Plasma Sources Sci. Technol. 27 025006) is used to investigate the effect of the driving frequency (over the range of 15–45 MHz) on the plasma uniformity in radio frequency (RF) capacitively coupled plasma (CCP) discharges in a geometrically symmetric reactor with a dielectric side wall in argon gas. The reactor size (12 cm electrode length, 2.5 cm gap) and driving frequency are sufficiently small that electromagnetic effects can be ignored. Previously, we showed (Liu et al 2018 Plasma Sources Sci. Technol. 27 025006) that for 15 MHz excitation, Ohmic heating of electrons by the electric field perpendicular to the electrodes is enhanced in a region in front of the dielectric side wall, leading to a maximum in electron density there. In this work we show that increasing the excitation frequency (at constant applied voltage amplitude) not only increases the overall electron heating and density but also causes a stronger, narrower peak in electron heating closer to the dielectric wall, improving the plasma uniformity along the electrodes. This heating peak comes both from enhanced perpendicular electron heating and from the appearance at high frequency of significant parallel heating. The latter is caused by the presence of a significant parallel-direction RF oscillating electric field in the corners. Whereas at the reactor center the sheaths oscillate perpendicularly to the electrodes, near the dielectric edge they move in and out of the corners and must be treated in two dimensions.

Increased frequency of chromosome translocations in airline pilots with long-term flying experience

PubMed Central

Yong, L C; Sigurdson, A J; Ward, E M; Waters, M A; Whelan, E A; Petersen, M R; Bhatti, P; Ramsey, M J; Ron, E; Tucker, J D

2008-01-01

Background Chromosome translocations are an established biomarker of cumulative exposure to external ionising radiation. Airline pilots are exposed to cosmic ionising radiation, but few flight crew studies have examined translocations in relation to flight experience. Methods We determined the frequency of translocations in the peripheral blood lymphocytes of 83 airline pilots and 50 comparison subjects (mean age 47 and 46 years, respectively). Translocations were scored in an average of 1039 cell equivalents (CE) per subject using fluorescence in situ hybridisation (FISH) whole chromo-some painting and expressed per 100 CE. Negative binomial regression models were used to assess the relationship between translocation frequency and exposure status and flight years, adjusting for age, diagnostic x ray procedures, and military flying. Results There was no significant difference in the adjusted mean translocation frequency of pilots and comparison subjects (0.37 (SE 0.04) vs 0.38 (SE 0.06) translocations/100 CE, respectively). However, among pilots, the adjusted translocation frequency was significantly associated with flight years (p = 0.01) with rate ratios of 1.06 (95% CI 1.01 to 1.11) and 1.81 (95% CI 1.16 to 2.82) for a 1- and 10-year incremental increase in flight years, respectively. The adjusted rate ratio for pilots in the highest compared to the lowest quartile of flight years was 2.59 (95% CI 1.26 to 5.33). Conclusions This data suggests that pilots with long-term flying experience may be exposed to biologically significant doses of ionising radiation. Epidemiological studies with longer follow-up of larger cohorts of pilots with a wide range of radiation exposure levels are needed to clarify the relationship between cosmic radiation exposure and cancer risk. PMID:19074211

Iterative metal artifact reduction: evaluation and optimization of technique.

PubMed

Subhas, Naveen; Primak, Andrew N; Obuchowski, Nancy A; Gupta, Amit; Polster, Joshua M; Krauss, Andreas; Iannotti, Joseph P

2014-12-01

Iterative metal artifact reduction (IMAR) is a sinogram inpainting technique that incorporates high-frequency data from standard weighted filtered back projection (WFBP) reconstructions to reduce metal artifact on computed tomography (CT). This study was designed to compare the image quality of IMAR and WFBP in total shoulder arthroplasties (TSA); determine the optimal amount of WFBP high-frequency data needed for IMAR; and compare image quality of the standard 3D technique with that of a faster 2D technique. Eight patients with nine TSA underwent CT with standardized parameters: 140 kVp, 300 mAs, 0.6 mm collimation and slice thickness, and B30 kernel. WFBP, three 3D IMAR algorithms with different amounts of WFBP high-frequency data (IMARlo, lowest; IMARmod, moderate; IMARhi, highest), and one 2D IMAR algorithm were reconstructed. Differences in attenuation near hardware and away from hardware were measured and compared using repeated measures ANOVA. Five readers independently graded image quality; scores were compared using Friedman's test. Attenuation differences were smaller with all 3D IMAR techniques than with WFBP (p < 0.0063). With increasing high-frequency data, the attenuation difference increased slightly (differences not statistically significant). All readers ranked IMARmod and IMARhi more favorably than WFBP (p < 0.05), with IMARmod ranked highest for most structures. The attenuation difference was slightly higher with 2D than with 3D IMAR, with no significant reader preference for 3D over 2D. IMAR significantly decreases metal artifact compared to WFBP both objectively and subjectively in TSA. The incorporation of a moderate amount of WFBP high-frequency data and use of a 2D reconstruction technique optimize image quality and allow for relatively short reconstruction times.

Increased frequency of chromosome translocations in airline pilots with long-term flying experience.

PubMed

Yong, L C; Sigurdson, A J; Ward, E M; Waters, M A; Whelan, E A; Petersen, M R; Bhatti, P; Ramsey, M J; Ron, E; Tucker, J D

2009-01-01

Chromosome translocations are an established biomarker of cumulative exposure to external ionising radiation. Airline pilots are exposed to cosmic ionising radiation, but few flight crew studies have examined translocations in relation to flight experience. We determined the frequency of translocations in the peripheral blood lymphocytes of 83 airline pilots and 50 comparison subjects (mean age 47 and 46 years, respectively). Translocations were scored in an average of 1039 cell equivalents (CE) per subject using fluorescence in situ hybridisation (FISH) whole chromosome painting and expressed per 100 CE. Negative binomial regression models were used to assess the relationship between translocation frequency and exposure status and flight years, adjusting for age, diagnostic x ray procedures, and military flying. There was no significant difference in the adjusted mean translocation frequency of pilots and comparison subjects (0.37 (SE 0.04) vs 0.38 (SE 0.06) translocations/100 CE, respectively). However, among pilots, the adjusted translocation frequency was significantly associated with flight years (p = 0.01) with rate ratios of 1.06 (95% CI 1.01 to 1.11) and 1.81 (95% CI 1.16 to 2.82) for a 1- and 10-year incremental increase in flight years, respectively. The adjusted rate ratio for pilots in the highest compared to the lowest quartile of flight years was 2.59 (95% CI 1.26 to 5.33). Our data suggests that pilots with long-term flying experience may be exposed to biologically significant doses of ionising radiation. Epidemiological studies with longer follow-up of larger cohorts of pilots with a wide range of radiation exposure levels are needed to clarify the relationship between cosmic radiation exposure and cancer risk.

Influence of apolipoprotein E genotype on senile dementia of the Alzheimer and Lewy body types. Significance for etiological theories of Alzheimer's disease.

PubMed

Harrington, C R; Louwagie, J; Rossau, R; Vanmechelen, E; Perry, R H; Perry, E K; Xuereb, J H; Roth, M; Wischik, C M

1994-12-01

Alzheimer's disease (AD) is associated with an increased frequency of the apolipoprotein E type epsilon 4 allele. To address both the disease and the allele specificity of this association, we have examined the apolipoprotein E allele distribution in 255 elderly persons including those with autopsy-confirmed AD, senile dementia of the Lewy body type (SDLT), vascular dementia, Parkinson's disease (PD) or Huntington's disease and in nondemented controls either with or without coronary complications. The epsilon 4 allele frequency was increased in SDLT (0.365) and AD (0.328) as compared with controls (0.147), PD (0.098), or Huntington's chorea (0.171). Coronary disease and vascular dementia were associated with marginally higher epsilon 4 allele frequencies than in controls. In PD, amyloid beta-protein accumulated to a greater extent in those cases possessing an epsilon 4 allele than in those without. Those PD cases with dementia were not distinguished from either controls or PD cases without dementia, whether tested biochemically or by apolipoprotein E genotype. It is the comparison of the results in AD and SDLT that yielded the most significant findings. There was a 1.8-fold excess of amyloid beta-protein in AD as compared with controls, and the levels in SDLT were intermediate between those in AD and controls. In contrast, AD was discriminated from both controls and SDLT by the substantial accumulation of paired helical filament tau and phosphorylated tau (both increased more than 20-fold as compared with controls). SDLT was nevertheless characterized by an increased epsilon 4 allele frequency in the absence of significant tau pathology (at least 10-fold less than that in AD). These findings indicate that tau processing is more specifically associated with AD than is amyloid beta-protein accumulation and that presence of the epsilon 4 allele is not an etiological factor that accounts for tau pathology.

Influence of apolipoprotein E genotype on senile dementia of the Alzheimer and Lewy body types. Significance for etiological theories of Alzheimer's disease.

PubMed Central

Harrington, C. R.; Louwagie, J.; Rossau, R.; Vanmechelen, E.; Perry, R. H.; Perry, E. K.; Xuereb, J. H.; Roth, M.; Wischik, C. M.

1994-01-01

Alzheimer's disease (AD) is associated with an increased frequency of the apolipoprotein E type epsilon 4 allele. To address both the disease and the allele specificity of this association, we have examined the apolipoprotein E allele distribution in 255 elderly persons including those with autopsy-confirmed AD, senile dementia of the Lewy body type (SDLT), vascular dementia, Parkinson's disease (PD) or Huntington's disease and in nondemented controls either with or without coronary complications. The epsilon 4 allele frequency was increased in SDLT (0.365) and AD (0.328) as compared with controls (0.147), PD (0.098), or Huntington's chorea (0.171). Coronary disease and vascular dementia were associated with marginally higher epsilon 4 allele frequencies than in controls. In PD, amyloid beta-protein accumulated to a greater extent in those cases possessing an epsilon 4 allele than in those without. Those PD cases with dementia were not distinguished from either controls or PD cases without dementia, whether tested biochemically or by apolipoprotein E genotype. It is the comparison of the results in AD and SDLT that yielded the most significant findings. There was a 1.8-fold excess of amyloid beta-protein in AD as compared with controls, and the levels in SDLT were intermediate between those in AD and controls. In contrast, AD was discriminated from both controls and SDLT by the substantial accumulation of paired helical filament tau and phosphorylated tau (both increased more than 20-fold as compared with controls). SDLT was nevertheless characterized by an increased epsilon 4 allele frequency in the absence of significant tau pathology (at least 10-fold less than that in AD). These findings indicate that tau processing is more specifically associated with AD than is amyloid beta-protein accumulation and that presence of the epsilon 4 allele is not an etiological factor that accounts for tau pathology. PMID:7992850

Can education improve clinical practice concerning delirium in older hospitalised patients? Results of a pre-test post-test study on an educational intervention for nursing staff.

PubMed

van Velthuijsen, Eveline L; Zwakhalen, Sandra M G; Warnier, Ron M J; Ambergen, Ton; Mulder, Wubbo J; Verhey, Frans R J; Kempen, Gertrudis I J M

2018-04-02

Delirium is a common and serious complication of hospitalisation in older adults. It can lead to prolonged hospital stay, institutionalisation, and even death. However, it often remains unrecognised or is not managed adequately. The aim of this study was to evaluate the effects of an educational intervention for nursing staff on three aspects of clinical practice concerning delirium in older hospitalised patients: the frequency and correctness of screening for delirium using the 13-item Delirium Observation Screening score (DOS), and the frequency of geriatric consultations requested for older patients. The a priori expectations were that there would be an increase in all three of these outcomes. We designed an educational intervention and implemented this on two inpatient hospital units. Before providing the educational session, the nursing staff was asked to fill out two questionnaires about delirium in older hospitalised patients. The educational session was then tailored to each unit based on the results of these questionnaires. Additionally, posters and flyers with information on the screening and management of delirium were provided and participants were shown where to find additional information. Relevant data (outcomes, demographics and background patient data) were collected retrospectively from digital medical files. Data was retrospectively collected for four different time points: three pre-test and one post-test. There was a significant increase in frequency of delirium screening (P = 0.001), and both units showed an increase in the correctness of the screening. No significant effect of the educational intervention was found for the proportion of patients who received a geriatric consultation (P = 0.083). The educational intervention was fairly successful in making positive changes in clinical practice: after the educational session an improvement in the frequency and correctness of screening for delirium was observed. A trend, though not significant, towards an increase in the proportion of geriatric consultations for older hospitalised patients was also observed.

Lubiprostone Accelerates Intestinal Transit and Alleviates Small Intestinal Bacterial Overgrowth in Patients With Chronic Constipation.

PubMed

Sarosiek, Irene; Bashashati, Mohammad; Alvarez, Alicia; Hall, Mark; Shankar, Nagasri; Gomez, Yvette; McCallum, Richard W; Sarosiek, Jerzy

2016-09-01

Lubiprostone is an effective treatment for chronic constipation (CC). The mechanism of action of lubiprostone is through increasing fluid secretion and lubrication of the intestinal lumen. The effects of lubiprostone on gastrointestinal transit and small intestinal bacterial overgrowth (SIBO) have not been adequately explored. The current study was designed to investigate whether lubiprostone (1) alters gastrointestinal transit and (2) affects SIBO in patients with constipation. A total of 29 female patients (mean age = 39 years; range: 19-64) with CC received 2 weeks of lubiprostone (24mcg b.i.d., P.O.). Stool consistency based on Bristol stool scale and the frequency of bowel movements (BMs) were recorded. Gastric emptying time, small bowel transit time, colon transit time (CTT), combined small and large bowel transit time (SLBTT) and whole gut transit time were measured using wireless motility capsule. The SIBO status was assessed by the lactulose breath test. Data were analyzed using Wilcoxon rank, Mann-Whitney U, Spearman׳s rank correlation and Chi-square tests. Lubiprostone significantly softened the stool and increased the frequency of BM from median of 2 to 4times per week. The CTT and SLBTT were significantly shorter in responders to lubiprostone (i.e., those with ≥ 2 times increase in the number of their weekly BM) compared with nonresponders. The higher frequency of BM after treatment was significantly correlated with the acceleration of CTT, SLBTT and whole gut transit time. In all, 17 out of 25 (68%) patients, who were tested for SIBO at baseline, were positive. In addition, 7 out of 17 (41%) SIBO-positive patients became SIBO-negative after lubiprostone treatment (P < 0.05). In CC, lubiprostone improves the frequency of BMs, softens the stool, accelerates intestinal transit and decreases accompanying SIBO. The improvement of SIBO could be explained by the cleansing effect of increased intestinal fluid and mucus combined with enhanced intestinal motility with lubiprostone. Copyright © 2016 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.

Opposite effects of high- and low-frequency transcranial random noise stimulation probed with visual motion adaptation

PubMed Central

Campana, Gianluca; Camilleri, Rebecca; Moret, Beatrice; Ghin, Filippo; Pavan, Andrea

2016-01-01

Transcranial random noise stimulation (tRNS) is a recent neuro-modulation technique whose effects at both behavioural and neural level are still debated. Here we employed the well-known phenomenon of motion after-effect (MAE) in order to investigate the effects of high- vs. low-frequency tRNS on motion adaptation and recovery. Participants were asked to estimate the MAE duration following prolonged adaptation (20 s) to a complex moving pattern, while being stimulated with either sham or tRNS across different blocks. Different groups were administered with either high- or low-frequency tRNS. Stimulation sites were either bilateral human MT complex (hMT+) or frontal areas. The results showed that, whereas no effects on MAE duration were induced by stimulating frontal areas, when applied to the bilateral hMT+, high-frequency tRNS caused a significant decrease in MAE duration whereas low-frequency tRNS caused a significant corresponding increase in MAE duration. These findings indicate that high- and low-frequency tRNS have opposed effects on the adaptation-dependent unbalance between neurons tuned to opposite motion directions, and thus on neuronal excitability. PMID:27934947

Dependence of palmar sweating response and central nervous system activity on the frequency of whole-body vibration.

PubMed

Ando, Hideo; Noguchi, Ryo

2003-06-01

This study was carried out to determine the effects of the frequency of whole-body vibration on palmar sweating response and the activity of the central sympathetic nervous system. Palmar sweating volume was measured on the right palm of six healthy men before and during 3 minutes of exposure to sinusoidal whole-body vibration at three different frequencies (16, 31.5, and 63 Hz). The whole-body vibration had a frequency-weighted, root mean square (rms) acceleration magnitude of 2.0 m/s2. As the index of the activated central sympathetic nervous system, saliva level of 3-methoxy-4-hydroxyphenylglycol (MHPG) was analyzed before and immediately after each vibration exposure. Each vibration frequency induced a palmar sweating response, that of 31.5 Hz being the largest. However, no significant difference was found between the three vibration conditions. Saliva MHPG increased in all the vibration exposures, and the largest change was observed at 31.5 Hz, the difference being significant. Acute exposure to whole-body vibration induced a palmar sweating response and activated the central sympathetic nervous system. The effects on the central nervous system were found to be dependent on the frequency of the vibration.

Effects of intranasal administration of epitalon on neuron activity in the rat neocortex.

PubMed

Sibarov, D A; Vol'nova, A B; Frolov, D S; Nozdrachev, A D

2007-11-01

This report discusses the properties of the synthetic tetrapeptide epitalon (Ala-Glu-Asp-Gly), synthesized on the basis of an epiphyseal peptide extract. Intranasal administration of epitalon was selected as a noninvasive means of applying the agent to the CNS by bypassing the blood-brain barrier. The aim of the present work was to assess the characteristics of the action of epitalon on the frequency of spontaneous neuron activity in the cerebral cortex of white rats. Studies were performed using male Wistar rats anesthetized with urethane (1 g/kg). Extracellular activity of cortical neurons was recorded with a glass microelectrode of resistance 1-2 MOmega. Recording of spontaneous neuron discharges for 10-15 min was followed by intranasal administration of epitalon solution and recording of neuron activity to 30 min after doses of 30 ng per animal. Significant activation of neuron activity was seen several minutes after dosage, with an increase (by factors of 2-2.5) in discharge frequency. In some experiments, the effect of epitalon was multiphasic. The first peak of increased neuron discharge frequency at 5-7 min was followed by peaks at 11-12 and 17-18 min. The increase in discharge frequency occurred because of an increase in the discharge frequency of neurons which were already active and the recruitment of previously silent neurons. At least the first peak of increased neuron activity following exposure to epitalon was found to be associated with the direct action of the peptide on cortical cells.

Catastrophic instabilities of modified DA-DC hybrid surface waves in a semi-bounded plasma system

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

Lee, Myoung-Jae; Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr

We find the catastrophic instabilities and derive the growth rates for the dust-cyclotron resonance (DCR) and dust-rotation resonance (DRR) modes of the modified dust-acoustic and dust-cyclotron (DA-DC) hybrid surface waves propagating at the plasma–vacuum interface where the plasma is semi-bounded and composed of electrons and rotating dust grains. The effects of magnetic field and dust rotation frequency on the DCR- and DDR-modes are also investigated. We find that the dust rotation frequency enhances the growth rate of DCR-mode and the effect of dust rotation on this resonance mode decreases with an increase of the wave number. We also find thatmore » an increase of magnetic field strength enhances the DCR growth rate, especially, for the short wavelength regime. In the case of DRR-mode, the growth rate is found to be decreased less sensitively with an increase of the wave number compared with the case of DCR, but much significantly enhanced by an increase of dust rotation frequency. The DRR growth rate also decreases with an increase of the magnetic field strength, especially in the long wavelength regime. Interestingly, we find that catastrophic instabilities occur for both DCR- and DRR-modes of the modified DA-DC hybrid surface waves when the rotational frequency is close to the dust-cyclotron frequency. Both modes can also be excited catastrophically due to the cooperative interaction between the DCR-mode and the DRR-mode.« less

Mouse current vocalization threshold measured with a neurospecific nociception assay: The effect of sex, morphine, and isoflurane

PubMed Central

Spornick, Nicholas; Guptill, Virginia; Koziol, Deloris; Wesley, Robert; Finkel, Julia; Quezado, Zenaide M.N.

2012-01-01

Sine-wave electrical stimulation at frequencies 2000, 250, and 5 Hz to respectively evaluate Aβ, Aδ, and C sensory neurons has recently been added to the armamentarium used to evaluate sensory neurons. We developed an automated nociception assay using sine-wave stimulation methodology to determine current vocalization threshold in response to 2000, 250, and 5 Hz and examine the effects of sex, analgesics, and anesthetics in mice. At baseline, males had significantly higher mean current vocalization thresholds compared with female mice at 2000, 250, and 5 Hz (p ≤ 0.019). By 1 h after intrathecal injections of morphine there were significant increases in current vocalization threshold percent changes from baseline that varied with doses (p = 0.0001) and frequency used (p < 0.0001). Specifically, with increasing doses of morphine, there were significantly greater increases in current vocalization threshold percent changes from baseline in response to 5 Hz compared with 250 and 2000 Hz stimulation in a significantly ordered pattern: 5 Hz > 250 Hz (p < 0.0001) and 250 Hz > 2000 Hz (p = 0.0002). Forty-five minutes after exposure, there were no effects of isoflurane on current vocalization thresholds at any frequency. Therefore, our findings suggest that this automated nociception assay using sine-wave stimulation in mice, can be valuable for measurements of the effects of sex, opioids, and anesthetics on the response to electrical stimuli that preferentially stimulate Aβ, Aδ, and C-sensory fibers in vivo. This investigation suggests the validation of this assay and supports its use to examine mechanisms of nociception in mice. PMID:21864576

Effects of temperature, moisture, and metal salt content on dielectric properties of rice bran associated with radio frequency heating.

PubMed

Ling, Bo; Liu, Xiaoli; Zhang, Lihui; Wang, Shaojin

2018-03-13

Dielectric heating including microwave (MW) and radio frequency (RF) energy has been regarded as alternative thermal treatments for food processing. To develop effective rice bran (RB) stabilization treatments based on RF and MW heating, dielectric properties (DPs) with dielectric constant (ε') and loss factor (ε″) of RB samples at frequencies (10-3000 MHz), temperatures (25-100 °C), moisture content (MC, 10.36-24.69% w.b.) and three metal salt levels (0.05-2.00%) were determined by an open-ended coaxial probe and impedance analyzer. Results indicated that both ε' and ε″ of RB samples increased with increasing temperature and MC. The increase rate was greater at higher temperature and moisture levels than at lower levels, especially at frequencies lower than 300 MHz. Cubic order models were developed to best fit the relationship between DPs of RB samples and temperature/MC at five frequencies with R 2 greater than 0.994. Both ε″ and RF heating rate of RB samples increased significantly with added NaCl (2%), KCl (1%) and Na 6 O 18 P 6 (2%). The obtained data are useful in developing computer models and simulating dielectric heating for RB stabilization and may also provide theoretical basis for synergistic stabilization of RB under combined dielectric heating with metal salts.

Mutagenicity and Potential Carcinogenicity of Thiopurine Treatment in Patients with Inflammatory Bowel Disease

PubMed Central

Nguyen, Truc; Vacek, Pamela M.; O’Neill, Patrick; Colletti, Richard B.; Finette, Barry A.

2009-01-01

The thiopurines, azathioprine and 6-mercaptopurine, are effective immune-modulators and cytotoxic agents extensively used in the treatment of autoimmune diseases, graft rejection, and cancer. There is compelling epidemiologic evidence that thiopurine treatment increases the risk for a variety of tumors by mechanisms that are unclear. We investigated the in vivo mutagenicity of long-term thiopurine treatment by determining the frequency and spectra of somatic mutation events at the HPRT locus in peripheral T lymphocytes as well as the prevalence of mutant clonal proliferation in a cross-sectional analysis of data from 119 children and adults with inflammatory bowel disease (IBD). Analyses of variance and regression were performed to assess relationships among the frequency and spectra of HPRT mutations with disease, duration of illness, duration of treatment and total therapeutic dose of azathioprine and 6-mercaptopurine. We observed a significant increase in the frequency of somatic mutations in 56 subjects treated with thiopurines for IBD compared to 63 subjects not treated with thiopurines. This increase was related to both total dose (p<0.001) and duration of treatment (p<0.001). Comparative mutation spectra analysis of 1,020 mutant isolates revealed a significant increase in the proportion of all transitions (p <0.001), in particular G:C to A:T transitions (p<0.001). Combined analyses of two signatures for mutant clonality, HPRT mutation and TCRβ CDR3 region unique gene sequence also demonstrated a significant thiopurine-dependent increase in mutant cell clonal proliferation (p<0.001). These findings provide in vivo evidence for mutation induction as a potential carcinogenic mechanism associated with chronic thiopurine intervention. PMID:19706768

Histamine facilitates GABAergic transmission in the rat entorhinal cortex: Roles of H1 and H2 receptors, Na+ -permeable cation channels, and inward rectifier K+ channels.

PubMed

Cilz, Nicholas I; Lei, Saobo

2017-05-01

In the brain, histamine (HA) serves as a neuromodulator and a neurotransmitter released from the tuberomammillary nucleus (TMN). HA is involved in wakefulness, thermoregulation, energy homeostasis, nociception, and learning and memory. The medial entorhinal cortex (MEC) receives inputs from the TMN and expresses HA receptors (H 1 , H 2 , and H 3 ). We investigated the effects of HA on GABAergic transmission in the MEC and found that HA significantly increased the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) with an EC 50 of 1.3 µM, but failed to significantly alter sIPSC amplitude. HA-induced increases in sIPSC frequency were sensitive to tetrodotoxin (TTX), required extracellular Ca 2+ , and persisted when GDP-β-S, a G-protein inactivator, was applied postsynaptically via the recording pipettes, indicating that HA increased GABA release by facilitating the excitability of GABAergic interneurons in the MEC. Recordings from local MEC interneurons revealed that HA significantly increased their excitability as determined by membrane depolarization, generation of an inward current at -65 mV, and augmentation of action potential firing frequency. Both H 1 and H 2 receptors were involved in HA-induced increases in sIPSCs and interneuron excitability. Immunohistochemical staining showed that both H 1 and H 2 receptors are expressed on GABAergic interneurons in the MEC. HA-induced depolarization of interneurons involved a mixed ionic mechanism including activation of a Na + -permeable cation channel and inhibition of a cesium-sensitive inward rectifier K + channel, although HA also inhibited the delayed rectifier K + channels. Our results may provide a cellular mechanism, at least partially, to explain the roles of HA in the brain. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Low-frequency electronic noise in single-layer MoS2 transistors.

PubMed

Sangwan, Vinod K; Arnold, Heather N; Jariwala, Deep; Marks, Tobin J; Lauhon, Lincoln J; Hersam, Mark C

2013-09-11

Ubiquitous low-frequency 1/f noise can be a limiting factor in the performance and application of nanoscale devices. Here, we quantitatively investigate low-frequency electronic noise in single-layer transition metal dichalcogenide MoS2 field-effect transistors. The measured 1/f noise can be explained by an empirical formulation of mobility fluctuations with the Hooge parameter ranging between 0.005 and 2.0 in vacuum (<10(-5) Torr). The field-effect mobility decreased, and the noise amplitude increased by an order of magnitude in ambient conditions, revealing the significant influence of atmospheric adsorbates on charge transport. In addition, single Lorentzian generation-recombination noise was observed to increase by an order of magnitude as the devices were cooled from 300 to 6.5 K.

Effect of neck geometry of resonance cells on noise reduction efficiency in sound-absorbing structures

NASA Astrophysics Data System (ADS)

Pisarev, P. V.; Anoshkin, A. N.; Pan'kov, A. A.

2016-10-01

The present work formulates the physical and mathematical models capable to forecast acoustic properties of resonance cells in sound absorbing structures. Distribution of acoustic pressure inside the duct and on sidewall cell was found, loss factor of output acoustic pressure wave was calculated for variety of geometric forms of cell's chamber and neck for monochromatic wave in 100-600Hz frequency range. Analysis of the acoustic pressure fields revealed that cell neck geometry strongly influences on cell resonant frequency and on outlet acoustic pressure loss factor. The effectiveness of the proposed by the authors biconical design of the resonant cell was proved, which increased acoustic radiation at the resonance frequency resulting significant increase of loss ratio of wave acoustic pressure at duct outlet.

Mathematical model of the seismic electromagnetic signals (SEMS) in non crystalline substances

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

Dennis, L. C. C.; Yahya, N.; Daud, H.

The mathematical model of seismic electromagnetic waves in non crystalline substances is developed and the solutions are discussed to show the possibility of improving the electromagnetic waves especially the electric field. The shear stress of the medium in fourth order tensor gives the equation of motion. Analytic methods are selected for the solutions written in Hansen vector form. From the simulated SEMS, the frequency of seismic waves has significant effects to the SEMS propagating characteristics. EM waves transform into SEMS or energized seismic waves. Traveling distance increases once the frequency of the seismic waves increases from 100% to 1000%. SEMSmore » with greater seismic frequency will give seismic alike waves but greater energy is embedded by EM waves and hence further distance the waves travel.« less

The acoustic and perceptual differences to the non-singer's singing voice before and after a singing vocal warm-up

NASA Astrophysics Data System (ADS)

DeRosa, Angela

The present study analyzed the acoustic and perceptual differences in non-singer's singing voice before and after a vocal warm-up. Experiments were conducted with 12 females who had no singing experience and considered themselves to be non-singers. Participants were recorded performing 3 tasks: a musical scale stretching to their most comfortable high and low pitches, sustained productions of the vowels /a/ and /i/, and singing performance of the "Star Spangled Banner." Participants were recorded performing these three tasks before a vocal warm-up, after a vocal warm-up, and then again 2-3 weeks later after 2-3 weeks of practice. Acoustical analysis consisted of formant frequency analysis, singer's formant/singing power ratio analysis, maximum phonation frequency range analysis, and an analysis of jitter, noise to harmonic ratio (NHR), relative average perturbation (RAP), and voice turbulence index (VTI). A perceptual analysis was also conducted with 12 listeners rating comparison performances of before vs. after the vocal warm-up, before vs. after the second vocal warm-up, and after both vocal warm-ups. There were no significant findings for the formant frequency analysis of the vowel /a/, but there was significance for the 1st formant frequency analysis of the vowel /i/. Singer's formant analyzed via Singing Power Ratio analysis showed significance only for the vowel /i/. Maximum phonation frequency range analysis showed a significant increase after the vocal warm-ups. There were no significant findings for the acoustic measures of jitter, NHR, RAP, and VTI. Perceptual analysis showed a significant difference after a vocal warm-up. The results indicate that a singing vocal warm-up can have a significant positive influence on the singing voice of non-singers.

Near doubling of storm rainfall

NASA Astrophysics Data System (ADS)

Feng, Zhe

2017-12-01

Large, intense thunderstorms frequently cause flooding and fatalities. Now, research finds that these storms may see a threefold increase in frequency and produce significantly heavier downpours in the future, far exceeding previous estimates.

Impact of acoustic airflow on intrasinus drug deposition: New insights into the vibrating mode and the optimal acoustic frequency to enhance the delivery of nebulized antibiotic.

PubMed

Leclerc, Lara; Merhie, Amira El; Navarro, Laurent; Prévôt, Nathalie; Durand, Marc; Pourchez, Jérémie

2015-10-15

We investigated the impact of vibrating acoustic airflow, the high frequency (f≥100 Hz) and the low frequency (f≤45 Hz) sound waves, on the enhancement of intrasinus drug deposition. (81m)Kr-gas ventilation study was performed in a plastinated human cast with and without the addition of vibrating acoustic airflow. Similarly, intrasinus drug deposition in a nasal replica using gentamicin as a marker was studied with and without the superposition of different modes of acoustic airflow. Ventilation experiments demonstrate that no sinus ventilation was observed without acoustic airflow although sinus ventilation occurred whatever the modes of acoustic airflow applied. Intrasinus drug deposition experiments showed that the high frequency acoustic airflow led to 4-fold increase in gentamicin deposition into the left maxillary sinus and to 2-fold deposition increase into the right maxillary sinus. Besides, the low frequency acoustic airflow demonstrated a significant increase of 4-fold and 2-fold in the right and left maxillary sinuses, respectively. We demonstrated the benefit of different modes of vibrating acoustic airflow for maxillary sinus ventilation and intrasinus drug deposition. The degree of gentamicin deposition varies as a function of frequency of the vibrating acoustic airflow and the geometry of the ostia. Copyright © 2015 Elsevier B.V. All rights reserved.

The Clinical Correlation of Regulatory T Cells and Cyclic Adenosine Monophosphate in Enterovirus 71 Infection

PubMed Central

Wang, Shih-Min; Chen, I-Chun; Liao, Yu-Ting; Liu, Ching-Chuan

2014-01-01

Background Brainstem encephalitis (BE) and pulmonary edema (PE) are notable complications of enterovirus 71 (EV71) infection. Objective This study investigated the immunoregulatory characterizations of EV71 neurological complications by disease severity and milrinone treatment. Study Design Patients <18 years with virologically confirmed EV71 infections were enrolled and divided into 2 groups: the hand, foot, and mouth disease (HFMD) or BE group, and the autonomic nervous system (ANS) dysregulation or PE group. Cytokine and cyclic adenosine monophosphate (cAMP) levels, and the regulatory T cell (Tregs) profiles of the patients were determined. Results Patients with ANS dysregulation or PE exhibited significantly low frequency of CD4+CD25+Foxp3+ and CD4+Foxp3+ T cells compared with patients with HFMD or BE. The expression frequency of CD4−CD8− was also significantly decreased in patients with ANS dysregulation or PE. Among patients with ANS dysregulation or PE, the expression frequency of CD4+Foxp3+ increased markedly after milrinone treatment, and was associated with reduction of plasma levels IL-6, IL-8 and IL-10. Plasma concentrations of cAMP were significantly decreased in patients with ANS dysregulation or PE compared with patients with HFMD or BE; however, cAMP levels increased after milrinone treatment. Conclusions These findings suggested decreased different regulatory T populations and cAMP expression correlate with increased EV71 disease severity. Improved outcome after milrinone treatment may associate with increased regulatory T populations, cAMP expression and modulation of cytokines levels. PMID:25010330

Simultaneous EEG/fMRI analysis of the resonance phenomena in steady-state visual evoked responses.

PubMed

Bayram, Ali; Bayraktaroglu, Zubeyir; Karahan, Esin; Erdogan, Basri; Bilgic, Basar; Ozker, Muge; Kasikci, Itir; Duru, Adil D; Ademoglu, Ahmet; Oztürk, Cengizhan; Arikan, Kemal; Tarhan, Nevzat; Demiralp, Tamer

2011-04-01

The stability of the steady-state visual evoked potentials (SSVEPs) across trials and subjects makes them a suitable tool for the investigation of the visual system. The reproducible pattern of the frequency characteristics of SSVEPs shows a global amplitude maximum around 10 Hz and additional local maxima around 20 and 40 Hz, which have been argued to represent resonant behavior of damped neuronal oscillators. Simultaneous electroencephalogram/functional magnetic resonance imaging (EEG/fMRI) measurement allows testing of the resonance hypothesis about the frequency-selective increases in SSVEP amplitudes in human subjects, because the total synaptic activity that is represented in the fMRI-Blood Oxygen Level Dependent (fMRI-BOLD) response would not increase but get synchronized at the resonance frequency. For this purpose, 40 healthy volunteers were visually stimulated with flickering light at systematically varying frequencies between 6 and 46 Hz, and the correlations between SSVEP amplitudes and the BOLD responses were computed. The SSVEP frequency characteristics of all subjects showed 3 frequency ranges with an amplitude maximum in each of them, which roughly correspond to alpha, beta and gamma bands of the EEG. The correlation maps between BOLD responses and SSVEP amplitude changes across the different stimulation frequencies within each frequency band showed no significant correlation in the alpha range, while significant correlations were obtained in the primary visual area for the beta and gamma bands. This non-linear relationship between the surface recorded SSVEP amplitudes and the BOLD responses of the visual cortex at stimulation frequencies around the alpha band supports the view that a resonance at the tuning frequency of the thalamo-cortical alpha oscillator in the visual system is responsible for the global amplitude maximum of the SSVEP around 10 Hz. Information gained from the SSVEP/fMRI analyses in the present study might be extrapolated to the EEG/fMRI analysis of the transient event-related potentials (ERPs) in terms of expecting more reliable and consistent correlations between EEG and fMRI responses, when the analyses are carried out on evoked or induced oscillations (spectral perturbations) in separate frequency bands instead of the time-domain ERP peaks.

Normal tissue complication probability (NTCP) models for late rectal bleeding, stool frequency and fecal incontinence after radiotherapy in prostate cancer patients.

PubMed

Schaake, Wouter; van der Schaaf, Arjen; van Dijk, Lisanne V; Bongaerts, Alfons H H; van den Bergh, Alfons C M; Langendijk, Johannes A

2016-06-01

Curative radiotherapy for prostate cancer may lead to anorectal side effects, including rectal bleeding, fecal incontinence, increased stool frequency and rectal pain. The main objective of this study was to develop multivariable NTCP models for these side effects. The study sample was composed of 262 patients with localized or locally advanced prostate cancer (stage T1-3). Anorectal toxicity was prospectively assessed using a standardized follow-up program. Different anatomical subregions within and around the anorectum were delineated. A LASSO logistic regression analysis was used to analyze dose volume effects on toxicity. In the univariable analysis, rectal bleeding, increase in stool frequency and fecal incontinence were significantly associated with a large number of dosimetric parameters. The collinearity between these predictors was high (VIF>5). In the multivariable model, rectal bleeding was associated with the anorectum (V70) and anticoagulant use, fecal incontinence was associated with the external sphincter (V15) and the iliococcygeal muscle (V55). Finally, increase in stool frequency was associated with the iliococcygeal muscle (V45) and the levator ani (V40). No significant associations were found for rectal pain. Different anorectal side effects are associated with different anatomical substructures within and around the anorectum. The dosimetric variables associated with these side effects can be used to optimize radiotherapy treatment planning aiming at prevention of specific side effects and to estimate the benefit of new radiation technologies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Dynamic Behaviour and Seismic Response of Ground Supported Cylindrical Water Tanks

NASA Astrophysics Data System (ADS)

Asha, Joseph; Glory, Joseph

2018-05-01

Liquid storage tank such as in water distribution systems, petroleum plants etc., constitute a vital component of life line systems. Reducing earthquake effects on liquid storage tanks, to minimize the environmental and economic impact of these effects, have always been an important engineering concern. In this paper, the dynamic behavior of cylindrical ground supported concrete water tanks with different aspect ratios is investigated using finite element software ANSYS. The natural frequencies and modal responses are obtained for impulsive and convective modes of vibration. The natural frequency of vibration of the tank is observed to be the lowest at maximum water depth. The fundamental impulsive frequency increases as water level reduces and for water level less than 1/3 of tank height, there is significantly no change in impulsive frequency. The effect of wall flexibility on dynamic behavior of the tank is investigated by performing the modal analysis of flexible and rigid tanks. For a partially filled tank, the results of the present study are of significant relevance. The response of the tank to the transient loading as horizontal ground motion of El Centro earthquake is studied for various water heights. As the height of water on the tank increases, the ultimate maximum seismic response parameters are also observed to be increased. The location of maximum hoop stress varies in accordance with the variations in input ground motion and water fill condition whereas shear and bending moment are maximum at the base.

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

Ambient noise causes independent changes in distinct spectro-temporal features of echolocation calls in horseshoe bats.

PubMed

Hage, Steffen R; Jiang, Tinglei; Berquist, Sean W; Feng, Jiang; Metzner, Walter

2014-07-15

One of the most efficient mechanisms to optimize signal-to-noise ratios is the Lombard effect - an involuntary rise in call amplitude due to ambient noise. It is often accompanied by changes in the spectro-temporal composition of calls. We examined the effects of broadband-filtered noise on the spectro-temporal composition of horseshoe bat echolocation calls, which consist of a constant-frequency component and initial and terminal frequency-modulated components. We found that the frequency-modulated components became larger for almost all noise conditions, whereas the bandwidth of the constant-frequency component increased only when broadband-filtered noise was centered on or above the calls' dominant or fundamental frequency. This indicates that ambient noise independently modifies the associated acoustic parameters of the Lombard effect, such as spectro-temporal features, and could significantly affect the bat's ability to detect and locate targets. Our findings may be of significance in evaluating the impact of environmental noise on echolocation behavior in bats. © 2014. Published by The Company of Biologists Ltd.

Blue whales respond to simulated mid-frequency military sonar

PubMed Central

Goldbogen, Jeremy A.; Southall, Brandon L.; DeRuiter, Stacy L.; Calambokidis, John; Friedlaender, Ari S.; Hazen, Elliott L.; Falcone, Erin A.; Schorr, Gregory S.; Douglas, Annie; Moretti, David J.; Kyburg, Chris; McKenna, Megan F.; Tyack, Peter L.

2013-01-01

Mid-frequency military (1–10 kHz) sonars have been associated with lethal mass strandings of deep-diving toothed whales, but the effects on endangered baleen whale species are virtually unknown. Here, we used controlled exposure experiments with simulated military sonar and other mid-frequency sounds to measure behavioural responses of tagged blue whales (Balaenoptera musculus) in feeding areas within the Southern California Bight. Despite using source levels orders of magnitude below some operational military systems, our results demonstrate that mid-frequency sound can significantly affect blue whale behaviour, especially during deep feeding modes. When a response occurred, behavioural changes varied widely from cessation of deep feeding to increased swimming speed and directed travel away from the sound source. The variability of these behavioural responses was largely influenced by a complex interaction of behavioural state, the type of mid-frequency sound and received sound level. Sonar-induced disruption of feeding and displacement from high-quality prey patches could have significant and previously undocumented impacts on baleen whale foraging ecology, individual fitness and population health. PMID:23825206

Effect of extended exposure to frequency-altered feedback on stuttering during reading and monologue.

PubMed

Armson, J; Stuart, A

1998-06-01

An ABA time series design was used to examine the effect of extended, continuous exposure to frequency-altered auditory feedback (FAF) during an oral reading and monologue task on stuttering frequency and speech rate. Twelve adults who stutter participated. A statistically significant decrease in number of stuttering events, an increase in number of syllables produced, and a decrease in percent stuttering was observed during the experimental segment relative to baseline segments for the oral reading task. In the monologue task, there were no statistically significant differences for the number of stuttering events, number of syllables produced, or percent stuttering between the experimental and baseline segments. Varying individual patterns of response to FAF were evident during the experimental segment of the reading task: a large consistent reduction in stuttering, an initial reduction followed by fluctuations in amount of stuttering, and essentially no change in stuttering frequency. Ten of 12 participants showed no reduction in stuttering frequency during the experimental segment of the monologue task. These findings have ramifications both for the clinical utilization of FAF and for theoretical explanations of fluency-enhancement.

Enhancement of Frequency Domain Indices of Heart Rate Variability by Cholinergic Stimulation with Pyridostigmine Bromide

PubMed Central

Zarei, Ali Asghar; Foroutan, Seyyed Abbas; Foroutan, Seyyed Mohsen; Erfanian Omidvar, Abbas

2011-01-01

Pyridostigmine bromide (PB) is a reversible cholinesterase inhibitor. The aim of this study was to determine the effect of orally administration of single dose sustained-released tablet of pyridostigmine bromide (PBSR) on the frequency domain indices of heart rate variability (HRV). Thirty-two healthy young men were participated in this study. They were divided into 2 groups; the pyridostigmine group (n = 22) and the placebo group (n = 10). Electrocardiogram (ECG) was recorded at 10, 30, 60, 90, 120, 150, 180, 210, 240, 300 and 420 min after PBSR administration. At each time, simultaneously, a blood sample was prepared and PB plasma concentration was measured by high-performance liquid chromatography (HPLC) method. Statistical analysis showed that in different indices of HRV, there is a significant increase in low frequency (LF) band at 300 min, but no difference in high frequency band (HF). It also showed significant decreases in normalized high frequency band (Hfnu), normalized low frequency band (Lfnu) and LF/HF ratio at 120, 240 and 300 min after PBSR administration. Maximum plasma concentration of PB was 150 min after the administration. In conclusion, administration of a single dose PBSR can enhance the frequency domains indices of HRV and improvesympathovagal balance. PMID:24250427

“Everyone Needs a Friend Sometimes” – Social Predictors of Long-Term Remission In First Episode Psychosis

PubMed Central

Bjornestad, Jone; Joa, Inge; Larsen, Tor K.; Langeveld, Johannes; Davidson, Larry; ten Velden Hegelstad, Wenche; Anda, Liss G.; Veseth, Marius; Melle, Ingrid; Johannessen, Jan O.; Bronnick, Kolbjorn

2016-01-01

Background: Predictors of long-term symptomatic remission are crucial to the successful tailoring of treatment in first episode psychosis. There is lack of studies distinguishing the predictive effects of different social factors. This prevents a valid evaluating of their independent effects. Objectives: To test specific social baseline predictors of long-term remission. We hypothesized that first, satisfaction with social relations predicts remission; second, that frequency of social interaction predicts remission; and third, that the effect of friend relationship satisfaction and frequency will be greater than that of family relations satisfaction and frequency. Material and Methods: A sample of first episode psychosis (n = 186) completed baseline measures of social functioning, as well as clinical assessments. We compared groups of remitted and non-remitted individuals using generalized estimating equations analyses. Results: Frequency of social interaction with friends was a significant positive predictor of remission over a two-year period. Neither global perceived social satisfaction nor frequency of family interaction showed significant effects. Conclusions: The study findings are of particular clinical importance since frequency of friendship interaction is a possibly malleable factor. Frequency of interaction could be affected through behavioral modification and therapy already from an early stage in the course, and thus increase remission rates. PMID:27757090

Child Physical Abuse and Adult Mental Health: A National Study

PubMed Central

Sugaya, Luisa; Hasin, Deborah S.; Olfson, Mark; Lin, Keng-Han; Grant, Bridget F.; Blanco, Carlos

2013-01-01

This study characterizes adults who report being physically abused during childhood, and examines associations of reported type and frequency of abuse with adult mental health. Data were derived from the 2000–2001 and 2004–2005 National Epidemiologic Survey on Alcohol and Related Conditions, a large cross-sectional survey of a representative sample (N = 43,093) of the U.S. population. Weighted means, frequencies, and odds ratios of sociodemographic correlates and prevalence of psychiatric disorders were computed. Logistic regression models were used to examine the strength of associations between child physical abuse and adult psychiatric disorders adjusted for sociodemographic characteristics, other childhood adversities, and comorbid psychiatric disorders. Child physical abuse was reported by 8% of the sample and was frequently accompanied by other childhood adversities. Child physical abuse was associated with significantly increased adjusted odds ratios (AORs) of a broad range of DSM-IV psychiatric disorders (AOR = 1.16–2.28), especially attention-deficit hyperactivity disorder, posttraumatic stress disorder, and bipolar disorder. A dose-response relationship was observed between frequency of abuse and several adult psychiatric disorder groups; higher frequencies of assault were significantly associated with increasing adjusted odds. The long-lasting deleterious effects of child physical abuse underscore the urgency of developing public health policies aimed at early recognition and prevention. PMID:22806701

Child physical abuse and adult mental health: a national study.

PubMed

Sugaya, Luisa; Hasin, Deborah S; Olfson, Mark; Lin, Keng-Han; Grant, Bridget F; Blanco, Carlos

2012-08-01

This study characterizes adults who report being physically abused during childhood, and examines associations of reported type and frequency of abuse with adult mental health. Data were derived from the 2000-2001 and 2004-2005 National Epidemiologic Survey on Alcohol and Related Conditions, a large cross-sectional survey of a representative sample (N = 43,093) of the U.S. population. Weighted means, frequencies, and odds ratios of sociodemographic correlates and prevalence of psychiatric disorders were computed. Logistic regression models were used to examine the strength of associations between child physical abuse and adult psychiatric disorders adjusted for sociodemographic characteristics, other childhood adversities, and comorbid psychiatric disorders. Child physical abuse was reported by 8% of the sample and was frequently accompanied by other childhood adversities. Child physical abuse was associated with significantly increased adjusted odds ratios (AORs) of a broad range of DSM-IV psychiatric disorders (AOR = 1.16-2.28), especially attention-deficit hyperactivity disorder, posttraumatic stress disorder, and bipolar disorder. A dose-response relationship was observed between frequency of abuse and several adult psychiatric disorder groups; higher frequencies of assault were significantly associated with increasing adjusted odds. The long-lasting deleterious effects of child physical abuse underscore the urgency of developing public health policies aimed at early recognition and prevention. Copyright © 2012 International Society for Traumatic Stress Studies.

Study on the change and acculturation of dietary pattern of Southeast Asian workers living in South Korea.

PubMed

Lee, Eun Jung; Lee, Kyung-Ran; Lee, Seung-Joo

2017-10-01

This study analyzed the dietary pattern of Southeast Asian workers (Vietnamese, Thais, Cambodians and Myanmar) living in South Korea in order to recognize the dietary changes after they moved to South Korea. Questionnaires were completed by 251 Southeast Asian workers living in South Korea. Using a self-administered questionnaire, we assessed the diets before and after living in the hometown and in South Korea. Significant changes observed in the Southeast Asian workers were decreased in consumption frequency of fresh fruits, cooked vegetables, rice noodles, green tea and glutinous rice, and increase in consumption of Kimchi, seaweed, milk, coffee and pizza. These changes were attributed to rapid dietary acculturation. The frequencies of eating homemade food were significantly decreased after they came to Korea except for Thais. Thais showed the highest frequencies of eating homemade food daily among others. 28.2% of respondents said their health condition had deteriorated after living in South Korea due to difficulties to adapt Korean food, increased frequencies of eating instant food, and lacking exercises. By providing understanding of the dietary patterns of Southeast Asian workers, these results can be used for preliminary data to develop a program for their Korean food adaptation. Copyright © 2017 Elsevier Ltd. All rights reserved.

A controlled trial of an intervention to improve urinary and fecal incontinence and constipation.

PubMed

Schnelle, John F; Leung, Felix W; Rao, Satish S C; Beuscher, Linda; Keeler, Emmett; Clift, Jack W; Simmons, Sandra

2010-08-01

To evaluate effects of a multicomponent intervention on fecal incontinence (FI) and urinary incontinence (UI) outcomes. Randomized controlled trial. Six nursing homes (NHs). One hundred twelve NH residents. Intervention subjects were offered toileting assistance, exercise, and choice of food and fluid snacks every 2 hours for 8 hours per day over 3 months. Frequency of UI and FI and rate of appropriate toileting as determined by direct checks from research staff. Anorectal assessments were completed on a subset of 29 residents. The intervention significantly increased physical activity, frequency of toileting, and food and fluid intake. UI improved (P=.049), as did frequency of bowel movements (P<.001) and percentage of bowel movements (P<.001) in the toilet. The frequency of FI did not change. Eighty-nine percent of subjects who underwent anorectal testing showed a dyssynergic voiding pattern, which could explain the lack of efficacy of this intervention program alone on FI. This multicomponent intervention significantly changed multiple risk factors associated with FI and increased bowel movements without decreasing FI. The dyssynergic voiding pattern and rectal hyposensitivity suggest that future interventions may have to be supplemented with bulking agents (fiber), biofeedback therapy, or both to improve bowel function. © 2010, Copyright the Authors. Journal compilation © 2010, The American Geriatrics Society.

FDTD simulation of radar cross section reduction by a collisional inhomogeneous magnetized plasma

NASA Astrophysics Data System (ADS)

Foroutan, V.; Azarmanesh, M. N.; Foroutan, G.

2018-02-01

The recursive convolution finite difference time domain method is addressed in the scattered field formulation and employed to investigate the bistatic radar cross-section (RCS) of a square conductive plate covered by a collisional inhomogeneous magnetized plasma. The RCS is calculated for two different configurations of the magnetic field, i.e., parallel and perpendicular to the plate. The results of numerical simulations show that, for a perpendicularly applied magnetic field, the backscattered RCS is significantly reduced when the magnetic field intensity coincides with the value corresponding to the electron cyclotron resonance. By increasing the collision frequency, the resonant absorption is suppressed, but due to enhanced wave penetration and bending, the reduction in the bistatic RCS is improved. At very high collision frequencies, the external magnetic field has no significant impact on the bistatic RCS reduction. Application of a parallel magnetic field has an adverse effect near the electron cyclotron resonance and results in a large and asymmetric RCS profile. But, the problem is resolved by increasing the magnetic field and/or the collision frequency. By choosing proper values of the collision frequency and the magnetic field intensity, a perpendicular magnetic field can be effectively used to reduce the bistatic RCS of a conductive plate.

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

Vibration stress relief of DH 36 rectangle welded plates

NASA Astrophysics Data System (ADS)

Li, Shuqi; Fang, Hongyuan

2018-03-01

Vibration stress relief (VSR) is widely used in reducing residual stress in welded structures. However, the effectiveness of this method is still instable in some circumstance. In this study, a covert negative treatment phenomenon was investigated, i.e. natural frequency of welded structures decreased after VSR but residual stress in one direction increased. When the alteration of natural frequency after VSR is significant, the residual stresses in both the longitudinal and transversal directions shall decrease. Otherwise, residual stresses may increase on one direction. Thus, sufficient power shall be applied to the welded structures to avoid negative results.

Exploring the Frequency Stability Limits of Whispering Gallery Mode Resonators for Metrological Applications

NASA Technical Reports Server (NTRS)

Chembo, Yanne K.; Baumgartel, Lukas; Grudinin, Ivan; Strekalov, Dmitry; Thompson, Robert; Yu, Nan

2012-01-01

Whispering gallery mode resonators are attracting increasing interest as promising frequency reference cavities. Unlike commonly used Fabry-Perot cavities, however, they are filled with a bulk medium whose properties have a significant impact on the stability of its resonance frequencies. In this context that has to be reduced to a minimum. On the other hand, a small monolithic resonator provides opportunity for better stability against vibration and acceleration. this feature is essential when the cavity operates in a non-laboratory environment. In this paper, we report a case study for a crystalline resonator, and discuss the a pathway towards the inhibition of vibration-and acceleration-induced frequency fluctuations.

Dispersal rates affect species composition in metacommunities of Sarracenia purpurea inquilines.

PubMed

Kneitel, Jamie M; Miller, Thomas E

2003-08-01

Dispersal among local communities can have a variety of effects on species composition and diversity at local and regional scales. Local conditions (e.g., resource and predator densities) can have independent effects, as well as interact with dispersal, to alter these patterns. Based on metacommunity models, we predicted that local diversity would show a unimodal relationship with dispersal frequency. We manipulated dispersal frequencies, resource levels, and the presence of predators (mosquito larvae) among communities found in the water-filled leaves of the pitcher plant Sarracenia purpurea. Diversity and abundance of species of the middle trophic level, protozoa and rotifers, were measured. Increased dispersal frequencies significantly increased regional species richness and protozoan abundance while decreasing the variance among local communities. Dispersal frequency interacted with predation at the local community scale to produce patterns of diversity consistent with the model. When predators were absent, we found a unimodal relationship between dispersal frequency and diversity, and when predators were present, there was a flat relationship. Intermediate dispersal frequencies maintained some species in the inquiline communities by offsetting extinction rates. Local community composition and the degree of connectivity between communities are both important for understanding species diversity patterns at local and regional scales.

Doppler-based motion compensation algorithm for focusing the signature of a rotorcraft.

PubMed

Goldman, Geoffrey H

2013-02-01

A computationally efficient algorithm was developed and tested to compensate for the effects of motion on the acoustic signature of a rotorcraft. For target signatures with large spectral peaks that vary slowly in amplitude and have near constant frequency, the time-varying Doppler shift can be tracked and then removed from the data. The algorithm can be used to preprocess data for classification, tracking, and nulling algorithms. The algorithm was tested on rotorcraft data. The average instantaneous frequency of the first harmonic of a rotorcraft was tracked with a fixed-lag smoother. Then, state space estimates of the frequency were used to calculate a time warping that removed the effect of a time-varying Doppler shift from the data. The algorithm was evaluated by analyzing the increase in the amplitude of the harmonics in the spectrum of a rotorcraft. The results depended upon the frequency of the harmonics and the processing interval duration. Under good conditions, the results for the fundamental frequency of the target (~11 Hz) almost achieved an estimated upper bound. The results for higher frequency harmonics had larger increases in the amplitude of the peaks, but significantly lower than the estimated upper bounds.

4th Generation ECR Ion Sources

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

Lyneis, Claude M.; Leitner, D.; Todd, D.S.

2008-12-01

The concepts and technical challenges related to developing a 4th generation ECR ion source with an RF frequency greater than 40 GHz and magnetic confinement fields greater than twice Becr will be explored in this paper. Based on the semi-empirical frequency scaling of ECR plasma density with the square of operating frequency, there should be significant gains in performance over current 3rd generation ECR ion sources, which operate at RF frequencies between 20 and 30 GHz. While the 3rd generation ECR ion sources use NbTi superconducting solenoid and sextupole coils, the new sources will need to use different superconducting materialsmore » such as Nb3Sn to reach the required magnetic confinement, which scales linearly with RF frequency. Additional technical challenges include increased bremsstrahlung production, which may increase faster than the plasma density, bremsstrahlung heating of the cold mass and the availability of high power continuous wave microwave sources at these frequencies. With each generation of ECR ion sources, there are new challenges to be mastered, but the potential for higher performance and reduced cost of the associated accelerator continue to make this a promising avenue for development.« less

Rheometric properties of canine vocal fold tissues: Variation with anatomic location

PubMed Central

Kimura, Miwako; Mau, Ted; Chan, Roger W.

2010-01-01

Objective To evaluate the in vitro rheometric properties of the canine vocal fold lamina propria and muscle at phonatory frequencies, and their changes with anatomic location. Methods Six canine larynges were harvested immediately postmortem. Viscoelastic shear properties of anterior, middle, and posterior portions of the vocal fold cover (lamina propria) as well as those of the medial thyroarytenoid (TA) muscle (vocalis muscle) were quantified by a linear, controlled-strain simple-shear rheometer. Measurements of elastic shear modulus (G’) and dynamic viscosity (η’) of the specimens were conducted with small-amplitude sinusoidal shear deformation over a frequency range of 1 Hz to 250 Hz. Results All specimens showed similar frequency dependence of the viscoelastic functions, with G’ gradually increasing with frequency and η’ decreasing with frequency monotonically. G’ and η’ of the canine vocalis muscle were significantly higher than those of the canine vocal fold cover, and η’ of the canine vocal fold cover was significantly higher than that of the human vocal fold cover. There were no significant differences in G’ and in η’ between different portions of the canine vocal fold cover. Conclusion These preliminary data based on the canine model suggested that the vocalis muscle, while in a relaxed state in vitro, is significantly stiffer and more viscous than the vocal fold cover during vibration at phonatory frequencies. For large-amplitude vocal fold vibration involving the medial portion of the TA muscle, such distinct differences in viscoelastic properties of different layers of the vocal fold should be taken into account in multi-layered biomechanical models of phonation. PMID:21035291

Frequency encoded auditory display of the critical tracking task

NASA Technical Reports Server (NTRS)

Stevenson, J.

1984-01-01

The use of auditory displays for selected cockpit instruments was examined. In auditory, visual, and combined auditory-visual compensatory displays of a vertical axis, critical tracking task were studied. The visual display encoded vertical error as the position of a dot on a 17.78 cm, center marked CRT. The auditory display encoded vertical error as log frequency with a six octave range; the center point at 1 kHz was marked by a 20-dB amplitude notch, one-third octave wide. Asymptotic performance on the critical tracking task was significantly better when using combined displays rather than the visual only mode. At asymptote, the combined display was slightly, but significantly, better than the visual only mode. The maximum controllable bandwidth using the auditory mode was only 60% of the maximum controllable bandwidth using the visual mode. Redundant cueing increased the rate of improvement of tracking performance, and the asymptotic performance level. This enhancement increases with the amount of redundant cueing used. This effect appears most prominent when the bandwidth of the forcing function is substantially less than the upper limit of controllability frequency.

Influence of Handrim Wheelchair Propulsion Training in Adolescent Wheelchair Users, A Pilot Study

PubMed Central

Dysterheft, Jennifer L.; Rice, Ian M.; Rice, Laura A.

2015-01-01

Ten full-time adolescent wheelchair users (ages 13–18) completed a total of three propulsion trials on carpet and tile surfaces, at a self-selected velocity, and on a concrete surface, at a controlled velocity. All trials were performed in their personal wheelchair with force and moment sensing wheels attached bilaterally. The first two trials on each surface were used as pre-intervention control trials. The third trial was performed after receiving training on proper propulsion technique. Peak resultant force, contact angle, stroke frequency, and velocity were recorded during all trials for primary analysis. Carpet and tile trials resulted in significant increases in contact angle and peak total force with decreased stroke frequency after training. During the velocity controlled trials on concrete, significant increases in contact angle occurred, as well as decreases in stroke frequency after training. Overall, the use of a training video and verbal feedback may help to improve short-term propulsion technique in adolescent wheelchair users and decrease the risk of developing upper limb pain and injury. PMID:26042217

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

Burin, M. J.; Simmons, G. G.; Ceja, H. G.

The filamentary discharge seen within commercial plasma globes is commonly enjoyed yet not well understood. Here, we investigate the discharge properties of a plasma globe using a variable high voltage amplifier. We find that increasing voltage magnitude increases the number of filaments while leaving their individual structure basically unchanged, a result typical of dielectric barrier discharges. The frequency of the voltage also affects filament population but more significantly changes filament structure, with more diffuse filaments seen at lower frequencies. Voltage polarity is observed to be important, especially at lower frequencies, where for negative-gradient voltages the discharge is more diffuse, notmore » filamentary. At late stages of the discharge circular structures appear and expand on the glass boundaries. We find no trend of discharge speed with respect to voltage variables, though this may be due to manufacturer sample-to-sample variation. Each voltage cycle the discharge expands outward at ∼10–15 km/s, a speed significantly higher than the estimated electron drift yet considerably lower than that observed for most streamers. We discuss the physics of these observations and their relation to similar discharges that can be found within nature and industry.« less

Evidence for Hitchhiking of Deleterious Mutations within the Human Genome

PubMed Central

Chun, Sung; Fay, Justin C.

2011-01-01

Deleterious mutations present a significant obstacle to adaptive evolution. Deleterious mutations can inhibit the spread of linked adaptive mutations through a population; conversely, adaptive substitutions can increase the frequency of linked deleterious mutations and even result in their fixation. To assess the impact of adaptive mutations on linked deleterious mutations, we examined the distribution of deleterious and neutral amino acid polymorphism in the human genome. Within genomic regions that show evidence of recent hitchhiking, we find fewer neutral but a similar number of deleterious SNPs compared to other genomic regions. The higher ratio of deleterious to neutral SNPs is consistent with simulated hitchhiking events and implies that positive selection eliminates some deleterious alleles and increases the frequency of others. The distribution of disease-associated alleles is also altered in hitchhiking regions. Disease alleles within hitchhiking regions have been associated with auto-immune disorders, metabolic diseases, cancers, and mental disorders. Our results suggest that positive selection has had a significant impact on deleterious polymorphism and may be partly responsible for the high frequency of certain human disease alleles. PMID:21901107

Gender influences sphincter of Oddi response to cholecystokinin in the prairie dog.

PubMed

Tierney, S; Qian, Z; Yung, B; Lipsett, P A; Pitt, H A; Sostre, S; Lillemoe, K D

1995-10-01

Although gallstones and disorders of biliary tract motility are both more common in women than men, sphincter of Oddi motility has not previously been compared between the sexes. In this study, cholescintigraphy (under ketamine and diazepam anesthesia) was used to determine gallbladder emptying rate and ejection fraction in response to cholecystokinin (CCK) in eight male and six female prairie dogs fed a nonlithogenic diet. Ten days later, under alpha-chloralose anesthesia, sphincter of Oddi phasic wave activity was monitored for 10-min intervals before (control), during 20 min of CCK infusion, and for 20 min after infusion. Gallbladder emptying rate and ejection fraction and baseline sphincter of Oddi frequency, amplitude, and motility index (= frequency x amplitude) did not differ significantly between the sexes. Sphincter of Oddi phasic wave frequency was increased during CCK infusion in both males and females, but the change in amplitude was significantly greater in females, than males. We conclude that the increased incidence of biliary tract disease in women may be due to altered sphincter of Oddi hormonal response.

The Interaction between Speed Camera Enforcement and Speed-Related Mass Media Publicity in Victoria, Australia

PubMed Central

Cameron, M. H.; Newstead, S. V.; Diamantopoulou, K.; Oxley, P.

2003-01-01

The objective was to measure the presence of any interaction between the effect of mobile covert speed camera enforcement and the effect of intensive mass media road safety publicity with speed-related themes. During 1999, the Victoria Police varied the levels of speed camera activity substantially in four Melbourne police districts according to a systematic plan. Camera hours were increased or reduced by 50% or 100% in respective districts for a month at a time, during months when speed-related publicity was present and during months when it was absent. Monthly frequencies of casualty crashes, and their severe injury outcome, in each district during 1996–2000 were analysed to test the effects of the enforcement, publicity and their interaction. Reductions in crash frequency were associated monotonically with increasing levels of speed camera ticketing, and there was a statistically significant 41% reduction in fatal crash outcome associated with very high camera activity. High publicity awareness was associated with 12% reduction in crash frequency. The interaction between the enforcement and publicity was not statistically significant. PMID:12941230

Deletion of p66Shc in mice increases the frequency of size-change mutations in the lacZ transgene.

PubMed

Beltrami, Elena; Ruggiero, Antonella; Busuttil, Rita; Migliaccio, Enrica; Pelicci, Pier Giuseppe; Vijg, Jan; Giorgio, Marco

2013-04-01

Upon oxidative challenge the genome accumulates adducts and breaks that activate the DNA damage response to repair, arrest, or eliminate the damaged cell. Thus, reactive oxygen species (ROS) generated by endogenous oxygen metabolism are thought to affect mutation frequency. However, few studies determined the mutation frequency when oxidative stress is reduced. To test whether in vivo spontaneous mutation frequency is altered in mice with reduced oxidative stress and cell death rate, we crossed p66Shc knockout (p66KO) mice, characterized by reduced intracellular concentration of ROS and by impaired apoptosis, with a transgenic line harboring multiple copies of the lacZ mutation reporter gene as part of a plasmid that can be recovered from organs into Escherichia coli to measure mutation rate. Liver and small intestine from 2- to 24-month-old, lacZ (p66Shc+/+) and lacZp66KO mice, were investigated revealing no difference in overall mutation frequency but a significant increase in the frequency of size-change mutations in the intestine of lacZp66KO mice. This difference was further increased upon irradiation of mice with X-ray. In addition, we found that knocking down cyclophilin D, a gene that facilitates mitochondrial apoptosis acting downstream of p66Shc, increased the size-change mutation frequency in small intestine. Size-change mutations also accumulated in death-resistant embryonic fibroblasts from lacZp66KO mice treated with H2 O2 . These results indicate that p66Shc plays a role in the accumulation of DNA rearrangements and suggest that p66Shc functions to clear damaged cells rather than affect DNA metabolism. © 2012 The Authors Aging Cell © 2012 Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland.

Local cochlear damage reduces local nonlinearity and decreases generator-type cochlear emissions while increasing reflector-type emissions.

PubMed

Dong, Wei; Olson, Elizabeth S

2010-03-01

Distortion product otoacoustic emissions (DPOAEs) originate in cochlear nonlinearity and emerge into the ear canal as an apparent sum of emission types, one of which (generator) travels directly out and the other (reflector) travels out following linear reflection. The present study explores intracochlear sources of DPOAEs via simultaneous ear canal and intracochlear pressure measurements in gerbils. A locally damaged cochlea was produced with reduced local intracochlear nonlinearity and significant elevation of the compound action potential thresholds at frequencies represented within the damaged region. In the DPOAE the comparison of healthy to locally damaged cochleae showed the following: (1) In the broad frequency region corresponding to the locally damaged best frequency, DPOAEs evoked by wider f(2)/f(1) stimuli decreased, consistent with the reduction in local nonlinearity. (2) DPOAEs evoked by narrow f(2)/f(1) stimuli often had a bimodal change, decreasing in a lower frequency band and increasing in a band just adjacent and higher, and the DPOAE phase-vs-frequency slope steepened. These changes confirm the complex nature of the DPOAE.

Frequency of EEG arousals from nocturnal sleep in normal subjects.

PubMed

Mathur, R; Douglas, N J

1995-06-01

Brief arousals are clinically important and increasingly scored during polysomnography. However, the frequency of arousals during routine polysomnography in the normal population is unknown. We performed overnight polysomnography in the 55 of 59 control subjects from a family practice list who were approached and agreed to undergo polysomnography. Awakenings were scored according to the criteria of Rechtschaffen and Kales and briefer arousals according to three different criteria, including the American Sleep Disorders Association (ASDA) definition. There was a mean of 4 [95% confidence interval (CI), 1-15) Rechtschaffen and Kales awakenings per hour, whereas the ASDA definition gave 21 (95% CI, 7-56) per hour slept. Arousal frequencies increased significantly (p < 0.001) with age in our subjects, who ranged from the late teens to early 70s. The high upper limit of the frequency of brief arousals was not altered by exclusion of patients who snored or had witnessed apneas or daytime sleepiness. It is important that those scoring arousals on routine polysomnography recognize that high arousal frequencies occur in the normal population on 1-night polysomnography.

Comedications alter drug-induced liver injury reporting frequency: Data mining in the WHO VigiBase™

PubMed Central

Suzuki, Ayako; Yuen, Nancy A.; Ilic, Katarina; Miller, Richard T.; Reese, Melinda J.; Brown, H. Roger; Ambroso, Jeffrey I.; Falls, J. Gregory; Hunt, Christine M.

2015-01-01

Polypharmacy is common, and may modify mechanisms of drug-induced liver injury. We examined the effect of these drug–drug interactions on liver safety reports of four drugs highly associated with hepatotoxicity. In the WHO VigiBase™, liver event reports were examined for acetaminophen, isoniazid, valproic acid, and amoxicillin/clavulanic acid. Then, we evaluated the liver event reporting frequency of these 4 drugs in the presence of co-reported medications. Each of the 4 primary drugs was reported as having more than 2000 liver events, and co-reported with more than 600 different medications. Overall, the effect of 2275 co-reported drugs (316 drug classes) on the reporting frequency was analyzed. Decreased liver event reporting frequency was associated with 245 drugs/122 drug classes, including anti-TNFα, opioids, and folic acid. Increased liver event reporting frequency was associated with 170 drugs/82 drug classes; in particular, halogenated hydrocarbons, carboxamides, and bile acid sequestrants. After adjusting for age, gender, and other co-reported drug classes, multiple co-reported drug classes were significantly associated with decreased/increased liver event reporting frequency in a drug-specific/unspecific manner. In conclusion, co-reported medications were associated with changes in the liver event reporting frequency of drugs commonly associated with hepatotoxicity, suggesting that comedications may modify drug hepatic safety. PMID:25988394

Stimulatory role of interleukin 10 in CD8+ T cells through STATs in gastric cancer.

PubMed

Xi, Jianjun; Xu, Mingzheng; Song, Zongchang; Li, Hongqiang; Xu, Shumin; Wang, Chunmei; Song, Haihan; Bai, Jianwen

2017-05-01

CD8 + T cells are considered to be critical in tumor surveillance and elimination. Increased CD8 + T cell frequency and function is associated with better prognosis in cancer patients. Interleukin 10 is a cytokine with controversial roles in CD8 + T cell-mediated anti-tumor immunity. We therefore examined the interleukin 10 expression and consumption in CD8 + T cells harvested from the peripheral blood and resected tumors of gastric cancer patients of stages II-IV. We found that the gastric cancer patients presented significantly elevated frequencies of interleukin 10-expressing cells in both CD4 + and CD8 + T cells compared to healthy controls. But distinctive from the interleukin 10-expressing CD4 + T cells, which increased in frequency in advanced cancer, the interleukin 10-expressing CD8 + T cells did not increase with cancer stage in the peripheral blood and actually decreased with cancer stage in resected tumor. Interleukin 10 and interleukin 10 receptor expression was also enriched in interferon gamma-expressing activated CD8 + T cells. Compared to interleukin 10-nonexpressing CD8 + T cells, interleukin 10 receptor-expressing CD8 + T cells secreted significantly elevated interferon gamma levels. Treatment of anti-CD3/CD28-stimulated, purified CD8 + T cells with interleukin 10 alone could significantly enhance CD8 + T cell survival, an effect dependent on interleukin 10 receptor expression. Interleukin 10 also increased CD8 + T cell proliferation synergistically with interferon gamma but not alone. Analysis of downstream signal transducer and activator of transcription molecules showed that interleukin 10 treatment significantly increased the phosphorylation of signal transducer and activator of transcription 3 and signal transducer and activator of transcription 1 to lesser extent. Together, these results demonstrate that interleukin 10 possessed stimulatory roles in activated CD8 + T cells from gastric cancer patients.

Multiple exposure routes of a pesticide exacerbate effects on a grazing mayfly.

PubMed

Pristed, Mathias Joachim Skov; Bundschuh, Mirco; Rasmussen, Jes Jessen

2016-09-01

Hydrophobic pesticides such as pyrethroid insecticides tend to occur in their soluble form mainly as transient pulses in streams. In addition, they are regularly detected in significant quantities adsorbed to stream sediments and other organic in-stream structures. Consequently, stream biota is likely subjected to pesticide exposure via multiple routes. In this study we aimed at investigating the influence of exposure routes for the pyrethroid insecticide lambda-cyhalothrin on the grazing mayfly Heptagenia sulphurea. Therefore, H. sulphurea was exposed to lambda-cyhalothrin via single- (water or biofilm) or biphasic exposure (water and biofilm) at environmentally realistic concentrations (0, 0.1, 1μgL(-1)) and exposure duration (2h) in a full factorial design (n=5). Mortality, moulting frequency, and biofilm accrual (proxy for feeding rate) were recorded subsequent to a 7 d post exposure period. Mortality significantly increased and moulting frequency significantly decreased with increasing concentrations of lambda-cyhalothrin in the water phase whereas exposure via biofilm prompted no significant effects on these endpoints (α=0.05). Effect predictions systematically underestimated and overestimated effects for mortality and moulting frequency, respectively. Similarly, mayfly feeding rate was significantly reduced by water phase exposure whereas pre-exposed biofilm did not significantly affect this variable. However, we found a significant but non-systematic interaction between water phase and biofilm exposure on mayfly feeding rate. Our results show that exposure to the same pesticide via multiple exposure routes may increase the magnitude of effects beyond the level predicted from single phase exposures which has clear implications for the aquatic risk assessment of hydrophobic pesticides. However, our results additionally reveal that interactions between pesticide exposure routes may vary between selected dependent variables. We emphasize that unravelling the underlying mechanisms causing these discrepancies in interactive effects between exposure routes is a major aspect that should receive further attention in future research. Copyright © 2016 Elsevier B.V. All rights reserved.

Dynamic modulation of epileptic high frequency oscillations by the phase of slower cortical rhythms.

PubMed

Ibrahim, George M; Wong, Simeon M; Anderson, Ryan A; Singh-Cadieux, Gabrielle; Akiyama, Tomoyuki; Ochi, Ayako; Otsubo, Hiroshi; Okanishi, Tohru; Valiante, Taufik A; Donner, Elizabeth; Rutka, James T; Snead, O Carter; Doesburg, Sam M

2014-01-01

Pathological high frequency oscillations (pHFOs) have been proposed to be robust markers of epileptic cortex. Oscillatory activity below this frequency range has been shown to be modulated by phase of lower frequency oscillations. Here, we tested the hypothesis that dynamic cross-frequency interactions involving pHFOs are concentrated within the epileptogenic cortex. Intracranial electroencephalographic recordings from 17 children with medically-intractable epilepsy secondary to focal cortical dysplasia were obtained. A time-resolved analysis was performed to determine topographic concentrations and dynamic changes in cross-frequency amplitude-to-phase coupling (CFC). CFC between pHFOs and the phase of theta and alpha rhythms was found to be significantly elevated in the seizure-onset zone compared to non-epileptic regions (p<0.01). Data simulations showed that elevated CFC could not be attributed to the presence of sharp transients or other signal properties. The phase of low frequency oscillations at which pHFO amplitudes were maximal was inconsistent at seizure initiation, yet consistently at the trough of the low frequency rhythm at seizure termination. Amplitudes of pHFOs were most significantly modulated by the phase of alpha-band oscillations (p<0.01). These results suggest that increased CFC between pHFO amplitude and alpha phase may constitute a marker of epileptogenic brain areas and may be relevant for understanding seizure dynamics. Copyright © 2013 Elsevier Inc. All rights reserved.

The theory and method of variable frequency directional seismic wave under the complex geologic conditions

NASA Astrophysics Data System (ADS)

Jiang, T.; Yue, Y.

2017-12-01

It is well known that the mono-frequency directional seismic wave technology can concentrate seismic waves into a beam. However, little work on the method and effect of variable frequency directional seismic wave under complex geological conditions have been done .We studied the variable frequency directional wave theory in several aspects. Firstly, we studied the relation between directional parameters and the direction of the main beam. Secondly, we analyzed the parameters that affect the beam width of main beam significantly, such as spacing of vibrator, wavelet dominant frequency, and number of vibrator. In addition, we will study different characteristics of variable frequency directional seismic wave in typical velocity models. In order to examine the propagation characteristics of directional seismic wave, we designed appropriate parameters according to the character of direction parameters, which is capable to enhance the energy of the main beam direction. Further study on directional seismic wave was discussed in the viewpoint of power spectral. The results indicate that the energy intensity of main beam direction increased 2 to 6 times for a multi-ore body velocity model. It showed us that the variable frequency directional seismic technology provided an effective way to strengthen the target signals under complex geological conditions. For concave interface model, we introduced complicated directional seismic technology which supports multiple main beams to obtain high quality data. Finally, we applied the 9-element variable frequency directional seismic wave technology to process the raw data acquired in a oil-shale exploration area. The results show that the depth of exploration increased 4 times with directional seismic wave method. Based on the above analysis, we draw the conclusion that the variable frequency directional seismic wave technology can improve the target signals of different geologic conditions and increase exploration depth with little cost. Due to inconvenience of hydraulic vibrators in complicated surface area, we suggest that the combination of high frequency portable vibrator and variable frequency directional seismic wave method is an alternative technology to increase depth of exploration or prospecting.

Tumor necrosis factor-α -308G/A gene polymorphism in Egyptian children with immune thrombocytopenic purpura.

PubMed

El Sissy, Maha H; El Sissy, A H; Elanwary, Sherif

2014-07-01

Immune thrombocytopenic purpura (ITP) is an autoimmune disease characterized by increased platelet destruction. Although the cause of ITP remains unclear, it is accepted that both environmental and genetic factors play an important role in the development of the disease. Children with ITP have a T-helper 1-type cytokine pattern with elevated levels of tumor necrosis factor-alpha (TNF-α) as in most autoimmune diseases. Researchers have shown that polymorphism in the TNF-α gene at position -308 affects gene transcriptions with increased TNF-α production. The current case-control study aimed at detecting the frequency of TNF-α -308G/A gene polymorphism as genetic markers in Egyptian children with ITP, and to clear out their possible role in choosing the treatment protocols of therapy, using PCR restriction fragment length polymorphism assay. Ninety-two ITP patients and 100 age and sex-matched healthy controls were recruited in the study. The results obtained revealed that the frequency of TNF-α -308A/A homotype in ITP patients was significantly higher than that of the controls, and conferred almost six-fold increased risk of ITP acquisition. The polymorphic A allele frequency was significantly higher in ITP patients than in the controls, conferring almost two-fold increased ITP risk. In conclusion, our study suggests the possibility that TNF-α -308 gene polymorphism may contribute to the susceptibility of childhood ITP in Egyptian children.

Behaviour of aqueous sulfamethizole solution and temperature effects in cold plasma oxidation treatment.

PubMed

Sokolov, Alexander; Louhi-Kultanen, Marjatta

2018-06-07

The increase in volume and variety of pharmaceuticals found in natural water bodies has become an increasingly serious environmental problem. The implementation of cold plasma technology, specifically gas-phase pulsed corona discharge (PCD), for sulfamethizole abatement was studied in the present work. It was observed that sulfamethizole is easily oxidized by PCD. The flow rate and pH of the solution have no significant effect on the oxidation. Treatment at low pulse repetition frequency is preferable from the energy efficiency point of view but is more time-consuming. The maximum energy efficiency was around 120 g/kWh at half-life and around 50 g/kWh at the end of the treatment. Increasing the solution temperature from room temperature to 50 °C led to a significant reaction retardation of the process and decrease in energy efficiency. The pseudo-first order reaction rate constant (k 1 ) grows with increase in pulse repetition frequency and does not depend on pH. By contrast, decreasing frequency leads to a reduction of the second order reaction rate constant (k 2 ). At elevated temperature of 50 °C, the k 1 , k 2 values decrease 2 and 2.9 times at 50 pps and 500 pps respectively. Lower temperature of 10 °C had no effect on oxidation efficiency compared with room temperature.

An Air Mass Based Approach to the Establishment of Spring Season Synoptic Characteristics in the Northeast United States

NASA Astrophysics Data System (ADS)

Zander, R.; Messina, A.; Godek, M. L.

2012-12-01

The spring season is indicative of marked meteorological, ecological, and biological changes across the Northeast United States. The onset of spring coincides with distinct meteorological phenomena including an increase in severe weather events and snow meltwaters that can cause localized flooding and other costly damages. Increasing and variable springtime temperatures also influence Northeast tourist operations and agricultural productivity. Even with the vested interest of industry in the season and public awareness of the dynamic characteristics of spring, the definition of spring remains somewhat arbitrary. The primary goal of this research is to obtain a synoptic meteorological definition of the spring season through an assessment of air mass frequency over the past 60 years. A secondary goal examines the validity of recent speculations that the onset and termination of spring has changed in recent decades, particularly since 1975. The Spatial Synoptic Classification is utilized to define daily air masses over the region. Annual and seasonal baseline frequencies are identified and their differences are acquired to characterize the season. Seasonal frequency departures of the early and late segments of the period of record around 1975 are calculated and examined for practical and statistical significance. The daily boundaries of early and late spring are then isolated and frequencies are obtained for these periods. Boundary frequencies are assessed across the period of record to identify important changes in the season's initiation and termination through time. Results indicate that the Northeast spring season is dominated by dry air masses, mainly the Dry Moderate and Dry Polar types. Significant differences in seasonal air mass frequency are also observed through time. Prior to 1975, higher frequencies of polar air mass types are detected while after 1975 there is an increase in the frequencies of both moderate and tropical types. This finding is also identified for the onset of spring. Late spring frequencies are similar but with more variability in all moist variety air mass frequencies. These findings indicate that, from a synoptic perspective, springs in the Northeast can be defined by dry air mass conditions through time but modern springs are also warmer than those of past decades and the initiation of the season is likely arriving earlier. The end of the Northeast spring season may also be represented by more variable day-to-day air mass conditions in modern times than detected in past decades. 1950 - 1975 (black) and 1976 - 2010 (gray) Philadelphia, PA Spring air mass frequency (%).

An electrohydrodynamic technique for rapid mixing in stationary droplets on digital microfluidic platforms.

PubMed

Samiei, Ehsan; de Leon Derby, Maria Diaz; den Berg, Andre Van; Hoorfar, Mina

2017-01-17

This paper presents an electrohydrodynamic technique for rapid mixing of droplets in open and closed digital microfluidic (DMF) platforms. Mixing is performed by applying a high frequency AC voltage to the coplanar or parallel electrodes, inducing circulation zones inside the droplet which results in rapid mixing of the content. The advantages of the proposed method in comparison to conventional mixing methods that operate based on transporting the droplet back and forth and side to side include 1) a shorter mixing time (as fast as 0.25 s), 2) the use of a fewer number of electrodes, reducing the size of the chip, and 3) the stationary nature of the technique which reduces the chance of cross-contamination and surface biofouling. Mixing using the proposed method is performed to create a uniform mixture after merging a water droplet with another droplet containing either particles or dye. The results show that increasing the frequency, and or the amplitude of the applied voltage, enhances the mixing process. However, actuation with a very high frequency and voltage may result in shedding pico-liter satellite droplets. Therefore, for each frequency there is an effective range of the amplitude which provides rapid mixing and avoids shedding satellite droplets. Also, the increase in the gap height between the two plates (for the closed DMF platforms) significantly enhances the mixing efficiency due to the lower viscous effects. Effects of the addition of salts and DNA to the samples were also studied. The electrothermal effect decreased for these cases, which was solved by increasing the frequency of the applied voltage. To assure the high frequency actuation does not increase the sample temperature excessively, the temperature change was monitored using a thermal imaging camera and it was found that the increase in temperature is negligible.

Vibrational collapse of boroxol rings in compacted B2O3 glasses: a study of Raman scattering and low temperature specific heat

NASA Astrophysics Data System (ADS)

Carini, Giovanni, Jr.; Carini, Giuseppe; D’Angelo, Giovanna; Federico, Mauro; Romano, Valentino

2018-05-01

Low and high frequency Raman scattering of B2O3 glasses, compacted under GPa pressures, has been performed to investigate structural changes due to increasing atomic packing. Compacted glasses, annealed at ambient temperature and pressure, experience a time-dependent decrease of the density to a smaller constant value over a period of few months, displaying a permanent plastic deformation. Increasing densification determines a parallel and progressive decrease of the intensity of the Boson peak and the main band at 808 cm‑1, both these modes arising from localized vibrations involving planar boroxol rings (B3O6), the glassy units formed from three basic BO3 triangles. The 808 cm‑1 mode preserves its frequency, while the BP evidences a well-defined frequency increase. The high-frequency multicomponent band between 1200 and 1600 cm‑1 also changes with increasing densification, disclosing a decreasing intensity of the 1260 cm‑1 mode due to oxygen vibrations of BO3 units bridging boroxol rings. This indicates the gradual vibrational collapse of groups formed from rings connected by more complex links than a single bridging oxygen. The observed behaviours suggest that glass compaction causes severe deformation of boroxol rings, determining a decrease of groups which preserve unaltered their vibrational activity. Growing glass densification stiffens the network and leads to a decrease of the excess heat capacity over the Debye prediction below 20 K, which is not accounted for by the hardening of the elastic continuum. By using the low-frequency Raman scattering to determine the temperature dependence of the heat capacity, it has been evaluated the density of low-frequency vibrational states which discloses a significant reduction of excess modes with increasing density.

Decreased frequency and duration of tooth brushing is a risk factor for endothelial dysfunction.

PubMed

Matsui, Shogo; Kajikawa, Masato; Maruhashi, Tatsuya; Iwamoto, Yumiko; Iwamoto, Akimichi; Oda, Nozomu; Kishimoto, Shinji; Hidaka, Takayuki; Kihara, Yasuki; Chayama, Kazuaki; Goto, Chikara; Aibara, Yoshiki; Nakashima, Ayumu; Noma, Kensuke; Taguchi, Akira; Higashi, Yukihito

2017-08-15

Periodontal disease is associated with endothelial dysfunction, leading to cardiovascular disease. The effect of detailed tooth brushing behavior, not only frequency but also duration of tooth brushing, on endothelial function is unclear. The purpose of this study was to evaluate the relationships of detailed methods of tooth brushing with vascular function. We evaluated flow-mediated vasodilation (FMD), nitroglycerine-induced vasodilation, and frequency and duration of tooth brushing in 896 subjects. We divided the subjects into three groups according to the frequency and duration of tooth brushing: low frequency and short duration group (

Effects of mechanical vibration on proliferation and osteogenic differentiation of human periodontal ligament stem cells.

PubMed

Zhang, Chunxiang; Li, Ji; Zhang, Linkun; Zhou, Yi; Hou, Weiwei; Quan, Huixin; Li, Xiaoyu; Chen, Yangxi; Yu, Haiyang

2012-10-01

Paradental tissues (alveolar bone, periodontal ligament (PDL), and gingiva) have the capacity to adapt to their functional environment. The principal cellular elements of the PDL play an important role in normal function, regeneration of periodontal tissue and in orthodontic treatment. Recently, several studies have shown that low-magnitude, high-frequency (LMHF) mechanical vibration can positively influence bone homeostasis; however, the mechanism and optimal conditions for LMHF mechanical vibration have not been elucidated. It has been speculated that LMHF mechanical vibration stimulations have a favourable influence on osteocytes, osteoblasts and their precursors, thereby enhancing the expression of osteoblastic genes involved in bone formation and remodelling. The objective of this study was to test the effect of LMHF mechanical vibration on proliferation and osteogenic differentiation of human PDL stem cells (PDLSCs). Human PDLSCs were isolated from premolar teeth and randomized into vibration (magnitude: 0.3g; frequency: 10-180 Hz; 30 min/24h) and static cultures. The effect of vibration on PDLSC proliferation, differentiation and osteogenic potential was assessed at the genetic and protein level. After LMHF mechanical vibration, PDLSC proliferation was decreased; however, this was accompanied by increased markers of osteogenesis in a frequency-dependent manner. Specifically, alkaline phosphatase activity gradually increased with the frequency of vibration, to a peak at 50 Hz, and the level of osteocalcin was significantly higher than control following vibration at 40 Hz, 50 Hz, 60 Hz, 90 Hz and 120 Hz. Levels of Col-I, Runx2 and Osterix were significantly increased by LMHF mechanical vibration at frequencies of 40 Hz and 50 Hz. Our data demonstrates that LMHF mechanical vibration promotes PDLSC osteogenic differentiation and implies the existence of a frequency-dependent effect of vibration on determining PDLSC commitment to the osteoblast lineage. Copyright © 2012 Elsevier Ltd. All rights reserved.

Blunted Day-Night Changes in Luteinizing Hormone Pulse Frequency in Girls With Obesity: the Potential Role of Hyperandrogenemia

PubMed Central

Collins, Jessicah S.; Beller, Jennifer P.; Burt Solorzano, Christine; Patrie, James T.; Chang, R. Jeffrey; Marshall, John C.

2014-01-01

Context: Puberty is marked by sleep-associated changes in LH pulse frequency and amplitude. Early pubertal girls with obesity exhibit blunted day-to-night changes in LH secretion; whether this occurs in late pubertal obese girls is unknown. Objective: The objective of the study was to test two hypotheses: 1) blunted day-to-night changes in LH secretion occur in both early and late pubertal obese girls, and 2) such alterations are specifically associated with hyperandrogenemia. Design: This was a cross-sectional analysis. Setting: The study was conducted at a clinical research center. Patients or Other Participants: Twenty-seven early pubertal, premenarcheal girls (12 of whom were obese) and 63 late pubertal (postmenarcheal) girls (27 of whom were obese) participated in the study. Intervention: Blood samples were taken every 10 minutes from 7:00 pm to 7:00 am. Main Outcome Measure: Change in LH pulse frequency [LH interpulse interval (IPI)] from daytime hours (7:00 pm-11:00 pm, while awake) to nighttime hours (11:00 pm to 7:00 am, while generally asleep). Results: Both nonobese and obese postmenarcheal girls demonstrated significant day-to-night decreases in LH pulse frequency (IPI increases of 33% and 16%, respectively), but day-to-night changes were blunted in obese girls (P = .004, obese vs nonobese). Day-to-night LH pulse frequency decreased significantly in postmenarcheal obese subjects with normal T concentrations (26% IPI increase) but not in those with hyperandrogenemia. Similar differences were evident for LH pulse amplitude. Nonobese and obese early pubertal girls exhibited nonsignificant differences in day-night LH pulse frequency (day to night IPI increase of 26% vs decrease of 1%, respectively). Conclusions: Day-to-night changes in LH pulse secretion are blunted in postmenarcheal obese adolescent girls. This phenomenon may in part reflect hyperandrogenemia. PMID:24780043

Ontogenetic Development of Weberian Ossicles and Hearing Abilities in the African Bullhead Catfish

PubMed Central

Lechner, Walter; Heiss, Egon; Schwaha, Thomas; Glösmann, Martin; Ladich, Friedrich

2011-01-01

Background The Weberian apparatus of otophysine fishes facilitates sound transmission from the swimbladder to the inner ear to increase hearing sensitivity. It has been of great interest to biologists since the 19th century. No studies, however, are available on the development of the Weberian ossicles and its effect on the development of hearing in catfishes. Methodology/Principal Findings We investigated the development of the Weberian apparatus and auditory sensitivity in the catfish Lophiobagrus cyclurus. Specimens from 11.3 mm to 85.5 mm in standard length were studied. Morphology was assessed using sectioning, histology, and X-ray computed tomography, along with 3D reconstruction. Hearing thresholds were measured utilizing the auditory evoked potentials recording technique. Weberian ossicles and interossicular ligaments were fully developed in all stages investigated except in the smallest size group. In the smallest catfish, the intercalarium and the interossicular ligaments were still missing and the tripus was not yet fully developed. Smallest juveniles revealed lowest auditory sensitivity and were unable to detect frequencies higher than 2 or 3 kHz; sensitivity increased in larger specimens by up to 40 dB, and frequency detection up to 6 kHz. In the size groups capable of perceiving frequencies up to 6 kHz, larger individuals had better hearing abilities at low frequencies (0.05–2 kHz), whereas smaller individuals showed better hearing at the highest frequencies (4–6 kHz). Conclusions/Significance Our data indicate that the ability of otophysine fish to detect sounds at low levels and high frequencies largely depends on the development of the Weberian apparatus. A significant increase in auditory sensitivity was observed as soon as all Weberian ossicles and interossicular ligaments are present and the chain for transmitting sounds from the swimbladder to the inner ear is complete. This contrasts with findings in another otophysine, the zebrafish, where no threshold changes have been observed. PMID:21533262

No correlation between germline mutation at repeat DNA and meiotic crossover in male mice exposed to X-rays or cisplatin.

PubMed

Barber, R; Plumb, M; Smith, A G; Cesar, C E; Boulton, E; Jeffreys, A J; Dubrova, Y E

2000-12-20

To test the hypothesis that mouse germline expanded simple tandem repeat (ESTR) mutations are associated with recombination events during spermatogenesis, crossover frequencies were compared with germline mutation rates at ESTR loci in male mice acutely exposed to 1Gy of X-rays or to 10mg/kg of the anticancer drug cisplatin. Ionising radiation resulted in a highly significant 2.7-3.6-fold increase in ESTR mutation rate in males mated 4, 5 and 6 weeks after exposure, but not 3 weeks after exposure. In contrast, irradiation had no effect on meiotic crossover frequencies assayed on six chromosomes using 25 polymorphic microsatellite loci spaced at approximately 20cM intervals and covering 421cM of the mouse genome. Paternal exposure to cisplatin did not affect either ESTR mutation rates or crossover frequencies, despite a report that cisplatin can increase crossover frequency in mice. Correlation analysis did not reveal any associations between the paternal ESTR mutation rate and crossover frequency in unexposed males and in those exposed to X-rays or cisplatin. This study does not, therefore, support the hypothesis that mutation induction at mouse ESTR loci results from a general genome-wide increase in meiotic recombination rate.

Beat-to-Beat Variability of Ventricular Action Potential Duration Oscillates at Low Frequency During Sympathetic Provocation in Humans

PubMed Central

Porter, Bradley; van Duijvenboden, Stefan; Bishop, Martin J.; Orini, Michele; Claridge, Simon; Gould, Justin; Sieniewicz, Benjamin J.; Sidhu, Baldeep; Razavi, Reza; Rinaldi, Christopher A.; Gill, Jaswinder S.; Taggart, Peter

2018-01-01

Background: The temporal pattern of ventricular repolarization is of critical importance in arrhythmogenesis. Enhanced beat-to-beat variability (BBV) of ventricular action potential duration (APD) is pro-arrhythmic and is increased during sympathetic provocation. Since sympathetic nerve activity characteristically exhibits burst patterning in the low frequency range, we hypothesized that physiologically enhanced sympathetic activity may not only increase BBV of left ventricular APD but also impose a low frequency oscillation which further increases repolarization instability in humans. Methods and Results: Heart failure patients with cardiac resynchronization therapy defibrillator devices (n = 11) had activation recovery intervals (ARI, surrogate for APD) recorded from left ventricular epicardial electrodes alongside simultaneous non-invasive blood pressure and respiratory recordings. Fixed cycle length was achieved by right ventricular pacing. Recordings took place during resting conditions and following an autonomic stimulus (Valsalva). The variability of ARI and the normalized variability of ARI showed significant increases post Valsalva when compared to control (p = 0.019 and p = 0.032, respectively). The oscillatory behavior was quantified by spectral analysis. Significant increases in low frequency (LF) power (p = 0.002) and normalized LF power (p = 0.019) of ARI were seen following Valsalva. The Valsalva did not induce changes in conduction variability nor the LF oscillatory behavior of conduction. However, increases in the LF power of ARI were accompanied by increases in the LF power of systolic blood pressure (SBP) and the rate of systolic pressure increase (dP/dtmax). Positive correlations were found between LF-SBP and LF-dP/dtmax (rs = 0.933, p < 0.001), LF-ARI and LF-SBP (rs = 0.681, p = 0.001) and between LF-ARI and LF-dP/dtmax (rs = 0.623, p = 0.004). There was a strong positive correlation between the variability of ARI and LF power of ARI (rs = 0.679, p < 0.001). Conclusions: In heart failure patients, physiological sympathetic provocation induced low frequency oscillation (~0.1 Hz) of left ventricular APD with a strong positive correlation between the LF power of APD and the BBV of APD. These findings may be of importance in mechanisms underlying stability/instability of repolarization and arrhythmogenesis in humans. PMID:29670531

Circulating CD14+ HLA-DR-/low myeloid-derived suppressor cells predicted early recurrence of hepatocellular carcinoma after surgery.

PubMed

Gao, Xing-Hui; Tian, Lu; Wu, Jiong; Ma, Xiao-Lu; Zhang, Chun-Yan; Zhou, Yan; Sun, Yun-Fan; Hu, Bo; Qiu, Shuang-Jian; Zhou, Jian; Fan, Jia; Guo, Wei; Yang, Xin-Rong

2017-09-01

Myeloid-derived suppressor cells (MDSCs) play an important role in tumor progression. The aim of the present study was to investigate the prognostic value of MDSCs for early recurrence of hepatocellular carcinoma (HCC) in patients undergoing curative resection. Myeloid-derived suppressor cells were measured by flow cytometry. The correlation between MDSCs and tumor recurrence was analyzed using a cohort of 183 patients who underwent curative resection between February 2014 and July 2015. Prognostic significance was further assessed using Kaplan-Meier survival estimates and log-rank tests. In vivo, CD14 + HLA-DR -/low MDSCs inhibit T cell proliferation and secretion. The frequency of CD14 + HLA-DR -/low MDSCs was significantly higher in HCC patients (3.7 ± 5.3%, n = 183) than in chronic hepatitis patients (1.4 ± 0.6%, n = 25) and healthy controls (1.1 ± 0.5%, n = 50). High frequency of MDSCs was significantly correlated with recurrence (time to recurrence) (P < 0.001) and overall survival (P = 0.034). Patients with HCC in the high MDSC group were prone to more vascular invasion (P = 0.018) and high systemic immune-inflammation index (SII) (P = 0.009) than those in the low MDSC group. Scatter-plot analyses revealed a significant positive correlation between the SII level and the frequency of MDSCs (r = 0.188, P = 0.011). Patients with HCC with a high MDSC frequency and high SII level had significantly shorter time to recurrence (P < 0.001) and overall survival (P = 0.028) than those with a low MDSC frequency and low SII. An increased frequency of MDSCs was correlated with early recurrence and predicted the prognosis of patients with HCC undergoing curative resection. The HCC patients with high frequency of MDSCs should be provided more advanced management and frequent monitoring. © 2016 The Japan Society of Hepatology.

Sustained Ex Vivo Susceptibility of Plasmodium falciparum to Artemisinin Derivatives but Increasing Tolerance to Artemisinin Combination Therapy Partner Quinolines in The Gambia

PubMed Central

Okebe, Joseph; Mbye, Haddijatou; Ceesay, Sukai; El-Fatouri, Fatima; Joof, Fatou; Nyang, Haddy; Janha, Ramatoulie; Affara, Muna; Ahmad, Abdullahi; Kolly, Olimatou; Nwakanma, Davis; D'Alessandro, Umberto

2017-01-01

ABSTRACT Antimalarial interventions have yielded a significant decline in malaria prevalence in The Gambia, where artemether-lumefantrine (AL) has been used as a first-line antimalarial for a decade. Clinical Plasmodium falciparum isolates collected from 2012 to 2015 were analyzed ex vivo for antimalarial susceptibility and genotyped for drug resistance markers (pfcrt K76T, pfmdr1 codons 86, 184, and 1246, and pfk13) and microsatellite variation. Additionally, allele frequencies of single nucleotide polymorphisms (SNPs) from other drug resistance-associated genes were compared from genomic sequence data sets from 2008 (n = 79) and 2014 (n = 168). No artemisinin resistance-associated pfk13 mutation was found, and only 4% of the isolates tested in 2015 showed significant growth after exposure to dihydroartemisinin. Conversely, the 50% inhibitory concentrations (IC50s) of amodiaquine and lumefantrine increased within this period. pfcrt 76T and pfmdr1 184F mutants remained at a prevalence above 80%. pfcrt 76T was positively associated with higher IC50s to chloroquine. pfmdr1 NYD increased in frequency between 2012 and 2015 due to lumefantrine selection. The TNYD (pfcrt 76T and pfmdr1 NYD wild-type haplotype) also increased in frequency following AL implementation in 2008. These results suggest selection for pfcrt and pfmdr1 genotypes that enable tolerance to lumefantrine. Increased tolerance to lumefantrine calls for sustained chemotherapeutic monitoring in The Gambia to minimize complete artemisinin combination therapy (ACT) failure in the future. PMID:28971859

A numerical study of the benefits of driving jellyfish bells at their natural frequency.

PubMed

Hoover, Alexander; Miller, Laura

2015-06-07

A current question in swimming and flight is whether or not driving flexible appendages at their resonant frequency results in faster or more efficient locomotion. It has been suggested that jellyfish swim faster when the bell is driven at its resonant frequency. The goal of this study was to determine whether or not driving a jellyfish bell at its resonant frequency results in a significant increase in swimming velocity. To address this question, the immersed boundary method was used to solve the fully coupled fluid structure interaction problem of a flexible bell in a viscous fluid. Free vibration numerical experiments were used to determine the resonant frequency of the jellyfish bell. The jellyfish bells were then driven at frequencies ranging from above and below the resonant frequency. We found that jellyfish do swim fastest for a given amount of applied force when the bells are driven near their resonant frequency. Nonlinear effects were observed for larger deformations, shifting the optimal frequency to higher than the resonant frequency. We also found that the benefit of resonant forcing decreases for lower Reynolds numbers. Published by Elsevier Ltd.

Effects of prolonged compression on the variations of haemoglobin oxygenation—assessment by spectral analysis of reflectance spectrophotometry signals

NASA Astrophysics Data System (ADS)

Li, Zengyong; Tam, Eric W. C.; Mak, Arthur F. T.; Lau, Roy Y. C.

2006-11-01

The consequences of rhythmical flow motion for nutrition and the oxygen supply to tissue are largely unknown. In this study, the periodic variations of haemoglobin oxygenation in compressed and uncompressed skin were evaluated with a reflection spectrometer using an in vivo Sprague-Dawley rat model. Skin compression was induced over the trochanter area by a locally applied external pressure of 13.3 kPa (100 mmHg) via a specifically designed pneumatic indentor. A total of 19 rats were used in this study. The loading duration is 6 h per day for four consecutive days. Haemoglobin oxygenation variations were quantified using spectral analysis based on wavelets' transformation. The results found that in both compressed and uncompressed skin, periodic variations of the haemoglobin oxygenation were characterized by two frequencies in the range of 0.01-0.05 Hz and 0.15-0.4 Hz. These frequency ranges coincide with those of the frequency range of the endothelial-related metabolic and myogenic activities found in the flow motion respectively. Tissue compression following the above loading schedule induced a significant decrease in the spectral amplitudes of frequency interval 0.01-0.05 Hz during the pre-occlusion period on day 3 and day 4 as compared to that on day 1 (p < 0.05). In contrast, at a frequency range of 0.15-0.4 Hz, prolonged compression caused a significant increase in spectral amplitude during the pre-occlusion period in the compressed tissue on day 3 (p = 0.041) and day 4 (p = 0.024) compared to that in the uncompressed tissue on day 1. These suggested that the variations of the haemoglobin oxygenation were closely related to the endothelial-related metabolic and myogenic activities. Increased amplitude in the frequency interval 0.15-0.4 Hz indicated an increased workload of the vascular smooth muscle and could be attributed to the increase of O2 consumption rates of arteriolar walls. The modification of vessel wall oxygen consumption might substantially affect the available oxygen supply to the compressed tissue. This mechanism might be involved in the process leading to pressure ulcer formation.

High storm surge events in Venice and the 11-yr solar cycle

NASA Astrophysics Data System (ADS)

Barriopedro, David; García-Herrera, Ricardo; Lionello, Piero; Pino, Cosimo

2010-05-01

In the last years the Venice lagoon has received much attention as a case of coastal vulnerability, mainly because of relative sea level rise and increase frequency of storm surge events, the so-called "aqua alta", which, particularly during autumn, cause the flooding of the Venice historical city center. Long-term fluctuations in solar activity and large-scale climate patterns have been suggested as feasible factors of flooding variability. This study explores the long-term frequency variability of High Surge Events (HSE) in Venice for the period 1948-2008 and its modulation by the 11-yr solar cycle. A significant decadal variability in the frequency of HSE is found in good correspondence with the 11-yr cycle, solar maxima being associated to a significant increase of the October-November-December HSE frequency. A Storm Surge Pattern (SSP), i.e. the seasonal 1000 hPa height pattern associated to increased frequency of HSE, is identified and found similar to the positive phase of the main variability mode of the regional atmospheric circulation (EOF1). However, further analyses indicate that the increase of HSE in solar maxima cannot be simply explained by a higher recurrence of positive EOF1 phases during high solar years. It rather seems that solar activity modulates the spatial patterns of the atmospheric circulation (EOF) and the favorable conditions for HSE occurrence (SSP). Thus, under solar maxima, the occurrence of HSE is enhanced by the EOF1, namely a large-scale wave train pattern that is symptomatic of storm track paths over northern Europe. Solar minima reveal a substantially different and less robust SSP, consisting of a meridionally oriented dipole with a preferred southward path of storm track activity, which is not associated to any EOF during low solar periods. It is concluded that solar activity plays an indirect role in the frequency of HSE by modulating the spatial patterns of the main modes of atmospheric regional variability, the favorable patterns for HSE occurrence and their mutual relationships, so that constructive interaction between them is enhanced during solar maxima and inhibited in solar minima.

Vast Volatility Matrix Estimation using High Frequency Data for Portfolio Selection*

PubMed Central

Fan, Jianqing; Li, Yingying; Yu, Ke

2012-01-01

Portfolio allocation with gross-exposure constraint is an effective method to increase the efficiency and stability of portfolios selection among a vast pool of assets, as demonstrated in Fan et al. (2011). The required high-dimensional volatility matrix can be estimated by using high frequency financial data. This enables us to better adapt to the local volatilities and local correlations among vast number of assets and to increase significantly the sample size for estimating the volatility matrix. This paper studies the volatility matrix estimation using high-dimensional high-frequency data from the perspective of portfolio selection. Specifically, we propose the use of “pairwise-refresh time” and “all-refresh time” methods based on the concept of “refresh time” proposed by Barndorff-Nielsen et al. (2008) for estimation of vast covariance matrix and compare their merits in the portfolio selection. We establish the concentration inequalities of the estimates, which guarantee desirable properties of the estimated volatility matrix in vast asset allocation with gross exposure constraints. Extensive numerical studies are made via carefully designed simulations. Comparing with the methods based on low frequency daily data, our methods can capture the most recent trend of the time varying volatility and correlation, hence provide more accurate guidance for the portfolio allocation in the next time period. The advantage of using high-frequency data is significant in our simulation and empirical studies, which consist of 50 simulated assets and 30 constituent stocks of Dow Jones Industrial Average index. PMID:23264708

Effects of long-term exercise training on autonomic control in myocardial infarction patients.

PubMed

Martinez, Daniel G; Nicolau, José C; Lage, Rony L; Toschi-Dias, Edgar; de Matos, Luciana D N J; Alves, Maria Janieire N N; Trombetta, Ivani C; Dias da Silva, Valdo J; Middlekauff, Holly R; Negrão, Carlos E; Rondon, Maria U P B

2011-12-01

Autonomic dysfunction, including baroreceptor attenuation and sympathetic activation, has been reported in patients with myocardial infarction (MI) and has been associated with increased mortality. We tested the hypotheses that exercise training (ET) in post-MI patients would normalize arterial baroreflex sensitivity (BRS) and muscle sympathetic nerve activity (MSNA), and long-term ET would maintain the benefits in BRS and MSNA. Twenty-eight patients after 1 month of uncomplicated MI were randomly assigned to 2 groups, ET (MI-ET) and untrained. A normal control group was also studied. ET consisted of three 60-minute exercise sessions per week for 6 months. We evaluated MSNA (microneurography), blood pressure (automatic oscillometric method), heart rate (ECG), and spectral analysis of RR interval, systolic arterial pressure (SAP), and MSNA. Baroreflex gain of SAP-RR interval and SAP-MSNA were calculated using the α-index. At 3 to 5 days and 1 month after MI, MSNA and low-frequency SAP were significantly higher and BRS significantly lower in MI patients when compared with the normal control group. ET significantly decreased MSNA (bursts per 100 heartbeats) and the low-frequency component of SAP and significantly increased the low-frequency component of MSNA and BRS of the RR interval and MSNA. These changes were so marked that the differences between patients with MI and the normal control group were no longer observed after ET. MSNA and BRS in the MI-untrained group did not change from baseline over the same time period. ET normalizes BRS, low-frequency SAP, and MSNA in patients with MI. These improvements in autonomic control are maintained by long-term ET. These findings highlight the clinical importance of this nonpharmacological therapy based on ET in the long-term treatment of patients with MI.

Maternal natural killer cell immunoglobulin receptor genes and human leukocyte antigen-C ligands influence recurrent spontaneous abortion in the Han Chinese population

PubMed Central

Su, Ning; Wang, Hongdan; Zhang, Bowei; Kang, Yiqing; Guo, Qiannan; Xiao, Hai; Yang, Hecai; Liao, Shixiu

2018-01-01

The underlying mechanism of recurrent spontaneous abortion (RSA) has remained elusive for many years. Several previous studies have suggested that the killer cell immunoglobulin receptor (KIR) gene family is associated with RSA, however, it is not clear exactly how. The present study detected KIR and human leukocyte antigen-C (HLA-C) genes in 110 Han Chinese women with unexplained RSA and 105 Han Chinese healthy females. The aim of the present study was to determine if certain genotypes were more susceptible to the occurrence of miscarriage. The frequency of KIR genes and different KIR haplotypes in the 2 groups demonstrated no statistical differences. However, in women who had miscarried ≥3 times, the frequency of KIR3DL1 was significantly reduced and the BB haplotype frequency was significantly higher compared with the control group. HLA-C2C2 was significantly increased in the KIR AB and KIR BB groups in the RSA groups compared with the control group. The women in the RSA group who had a homozygous HLA-C2C2 had a significantly higher frequency of the 2DS1 gene compared with the control group. The reduction of inhibitory gene and increased activation combinations may induce the activation of uterine natural killer cells, which may reduce the probability of fetal survival. To the best of our knowledge, the present study is the first report demonstrating the association between maternal KIR and HLA-C genes and RSA in women of a Han Chinese ethnicity. The present study revealed that females who miscarry ≥3 times may be used as selection criteria for RSA and so may exhibit higher research value. PMID:29387191

Genotoxicity testing of two lead-compounds in somatic cells of Drosophila melanogaster.

PubMed

Carmona, Erico R; Creus, Amadeu; Marcos, Ricard

2011-09-18

The in vivo genotoxic activity of two inorganic lead compounds was studied in Drosophila melanogaster by measurement of two different genetic endpoints. We used the wing-spot test and the comet assay. The comet assay was conducted with larval haemocytes. The results from the wing-spot test showed that neither lead chloride, PbCl(2), nor lead nitrate, Pb(NO(3))(2), were able to induce significant increases in the frequency of mutant spots. In addition, the combined treatments with gamma-radiation and PbCl(2) or Pb(NO(3))(2) did not show significant variations in the frequency of the three categories of mutant spots recorded, compared with the frequency induced by gamma-radiation alone. This seems to indicate that the lead compounds tested do not interact with the repair of the genetic damage induced by ionizing radiation. When the lead compounds were evaluated in the in vivo comet assay with haemocytes, Pb(NO(3))(2) was effective in inducing significant increases of DNA damage with a direct dose-response pattern. These results confirm the usefulness of the comet assay with haemocytes as an in vivo model and support the assumption that there is a genotoxic risk associated with lead exposure. Copyright © 2011 Elsevier B.V. All rights reserved.

Costs and benefits of larval jumping behaviour of Bathyplectes anurus.

PubMed

Saeki, Yoriko; Tani, Soichiro; Fukuda, Katsuto; Iwase, Shun-ichiro; Sugawara, Yuma; Tuda, Midori; Takagi, Masami

2016-02-01

Bathyplectes anurus, a parasitoid of the alfalfa weevils, forms a cocoon in the late larval stage and exhibits jumping behaviour. Adaptive significance and costs of the cocoon jumping have not been thoroughly studied. We hypothesised that jumping has the fitness benefits of enabling habitat selection by avoiding unfavourable environments. We conducted laboratory experiments, which demonstrated that jumping frequencies increased in the presence of light, with greater magnitudes of temperature increase and at lower relative humidity. In addition, when B. anurus individuals were allowed to freely jump in an arena with a light gradient, more cocoons were found in the shady area, suggesting microhabitat selection. In a field experiment, mortality of cocoons placed in the sun was significantly higher than for cocoons placed in the shade. B. anurus cocoons respond to environmental stress by jumping, resulting in habitat selection. In the presence of potential predators (ants), jumping frequencies were higher than in the control (no ant) arenas, though jumping frequencies decreased after direct contact with the predators. Body mass of B. anurus cocoons induced to jump significantly decreased over time than cocoons that did not jump, suggesting a cost to jumping. We discuss the benefits and costs of jumping behaviour and potential evolutionary advantages of this peculiar trait, which is present in a limited number of species.

Piezohydraulic Pump Development

NASA Technical Reports Server (NTRS)

Lynch, Christopher S.

2005-01-01

Reciprocating piston piezohydraulic pumps were developed originally under the Smart Wing Phase II program (Lynch) and later under the CHAP program (CSA, Kinetic Ceramics). These pumps focused on 10 cm scale stack actuators operating below resonance and, more recently, at resonance. A survey of commercially available linear actuators indicates that obtaining power density and specific power greater than electromagnetic linear actuators requires driving the stacks at frequencies greater than 1 KHz at high fields. In the case of 10 cm scale actuators the power supply signal conditioning becomes large and heavy and the soft PZT stack actuators generate a lot of heat due to internal losses. Reciprocation frequencies can be increased and material losses significantly decreased through use of millimeter scale single crystal stack actuators. We are presently targeting the design of pumps that utilize stacks at the 1-10 mm length scale and run at reciprocating frequencies of 20kHz or greater. This offers significant advantages over current approaches including eliminating audible noise and significantly increasing the power density and specific power of the system (including electronics). The pump currently under development will comprise an LC resonant drive of a resonant crystal and head mass operating against a resonant fluid column. Each of these resonant systems are high Q and together should produce a single high Q second order system.

Measurement of magnetostatic mode excitation and relaxation in permalloy films using scanning Kerr imaging

NASA Astrophysics Data System (ADS)

Tamaru, S.; Bain, J. A.; van de Veerdonk, R. J. M.; Crawford, T. M.; Covington, M.; Kryder, M. H.

2004-09-01

This work presents experimental results of magnetostatic mode excitation using scanning Kerr microscopy under continuous sinusoidal excitation in the microwave frequency range. This technique was applied to 100nm thick permalloy coupons excited in two different ways. In the first experiment, the uniform (Kittel) mode was excited at frequencies in 2.24-8.00GHz . The resonant condition was effectively described with the conventional Kittel mode equation. The LLG damping parameter α increased significantly with decreasing bias field. It was confirmed that this increase was caused by multidomain structure and ripple domains formed under weak bias fields, as suggested by other studies. In the second experiment, propagating magnetostatic mode surface waves were excited. They showed an exponential amplitude decay and a linear phase variation with distance from the drive field source, consistent with a decaying plane wave. The Damon-Eshbach (DE) model was extended to include a finite energy damping and used to analyze the results. It was found that the wave number and the decay constant were reasonably well described by the extended DE model. In contrast to the first experiment, no significant variation of α with frequency or bias field was seen in this second experiment, where spatial inhomogeneities in the magnetization are less significant.

Increased Release of Serotonin in the Spinal Cord During Low, But Not High, Frequency Transcutaneous Electric Nerve Stimulation in Rats With Joint Inflammation

PubMed Central

Sluka, Kathleen A.; Lisi, Tammy L.; Westlund, Karin N.

2009-01-01

Objective To determine the release pattern of serotonin and noradrenaline in the spinal cord in response to transcutaneous electric nerve stimulation (TENS) delivered at low or high frequency. Design Prospective randomized allocation of 3 treatments. Setting Research laboratory. Animals Male Sprague-Dawley rats (weight range, 250–350g). Intervention Knee joints of rats were inflamed with a mixture of 3% carrageenan and 3% kaolin for 24 hours prior to placement of push-pull cannulae into the dorsal horn of the spinal cord. Push-pull samples were collected in 10-minute intervals before, during, and after treatment with low-frequency TENS (4Hz), high-frequency TENS (100Hz), or sham TENS. TENS was applied to the inflamed knee joint for 20 minutes at sensory intensity and 100-μs pulse duration. Push-pull samples were analyzed for serotonin and noradrenaline by high performance liquid chromatography with coulemetric detection. Main Outcome Measures Spinal concentrations of serotonin and noradrenaline. Results Low-frequency TENS significantly increased serotonin concentrations during and immediately after treatment. There was no change in serotonin with high-frequency TENS, nor was there a change in noradrenaline with low- or high-frequency TENS. Conclusions Low-frequency TENS releases serotonin in the spinal cord to produce antihyperalgesia by activation of serotonin receptors. PMID:16876561

Head Impact Exposure in Junior and Adult Australian Football Players

PubMed Central

King, Doug; Dempsey, Alasdair; Murphy, Myles

2018-01-01

This study measured and compared the frequency, magnitude, and distribution of head impacts sustained by junior and adult Australian football players, respectively, and between player positions over a season of games. Twelve junior and twelve adult players were tracked using a skin-mounted impact sensor. Head impact exposure, including frequency, magnitude, and location of impacts, was quantified using previously established methods. Over the collection period, there were no significant differences in the impact frequency between junior and adult players. However, there was a significant increase in the frequency of head impacts for midfielders in both grades once we accounted for player position. A comparable amount of head impacts in both junior and adult players has implications for Australian football regarding player safety and medical coverage as younger players sustained similar impact levels as adult players. The other implication of a higher impact profile within midfielders is that, by targeting education and prevention strategies, a decrease in the incidence of sports-related concussion may result. PMID:29805979

Responses of a tall building in Los Angeles, California as inferred from local and distant earthquakes

USGS Publications Warehouse

Çelebi, Mehmet; Hasan Ulusoy,; Nori Nakata,

2016-01-01

Increasing inventory of tall buildings in the United States and elsewhere may be subjected to motions generated by near and far seismic sources that cause long-period effects. Multiple sets of records that exhibited such effects were retrieved from tall buildings in Tokyo and Osaka ~ 350 km and 770 km from the epicenter of the 2011 Tohoku earthquake. In California, very few tall buildings have been instrumented. An instrumented 52-story building in downtown Los Angeles recorded seven local and distant earthquakes. Spectral and system identification methods exhibit significant low frequencies of interest (~0.17 Hz, 0.56 Hz and 1.05 Hz). These frequencies compare well with those computed by transfer functions; however, small variations are observed between the significant low frequencies for each of the seven earthquakes. The torsional and translational frequencies are very close and are coupled. Beating effect is observed in at least two of the seven earthquake data.

Association of autonomic nervous system and EEG scalp potential during playing 2D Grand Turismo 5.

PubMed

Subhani, Ahmad Rauf; Likun, Xia; Saeed Malik, Aamir

2012-01-01

Cerebral activation and autonomic nervous system have importance in studies such as mental stress. The aim of this study is to analyze variations in EEG scalp potential which may influence autonomic activation of heart while playing video games. Ten healthy participants were recruited in this study. Electroencephalogram (EEG) and electrocardiogram (ECG) signals were measured simultaneously during playing video game and rest conditions. Sympathetic and parasympathetic innervations of heart were evaluated from heart rate variability (HRV), derived from the ECG. Scalp potential was measured by the EEG. The results showed a significant upsurge in the value theta Fz/alpha Pz (p<0.001) while playing game. The results also showed tachycardia while playing video game as compared to rest condition (p<0.005). Normalized low frequency power and ratio of low frequency/high frequency power were significantly increased while playing video game and normalized high frequency power sank during video games. Results showed synchronized activity of cerebellum and sympathetic and parasympathetic innervation of heart.

The effects of Robertsonian fusions on chiasma frequency and distribution in the house mouse (Mus musculus domesticus) from a hybrid zone in northern Scotland.

PubMed

Bidau, C J; Giménez, M D; Palmer, C L; Searle, J B

2001-09-01

Chiasma frequency and distribution were studied in male Mus musculus domesticus from the John O'Groats-standard chromosomal hybrid zone in northern Scotland. Individuals of the John O'Groats race (2n=32; homozygous for the Robertsonian fusions 4.10, 6.13, 9.12 and 11.14) and the standard race (2n=40, all telocentric), and hybrids with various karyotypes, were examined. Chiasma frequency was significantly negatively correlated with the number of Robertsonian configurations in the meiotic cell. The decrease of chiasma frequency can be attributed to intrachromosomal effects that reduce the number of chiasmata in Robertsonian bivalents (formed in homozygotes for Robertsonian fusions) and trivalents (formed in heterozygotes). However, the reduction is more pronounced in Robertsonian bivalents and is related to a shift of chiasmata to the distal ends of the chromosome arms. A different type of repatterning occurs in trivalents where there is a significant increase in proximal and interstitial chiasmata.

Optimisation of frequency-modulated characteristics of output radiation in a lidar with Raman amplification

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

Grigorievsky, V I; Tezadov, Ya A

2016-03-31

The reported study is aimed at increasing the power in the transmission path of a lidar with Raman amplification for longpath sensing of methane by optimising the frequency-modulated characteristics of the output radiation. The pump current of the used distributed-feedback master laser was modulated by a linearfrequency signal with simultaneous application of a non-synchronous high-frequency signal. For such a modulation regime, the Raman amplifier provided the mean output power of 2.5 W at a wavelength of 1650 nm. The spectral broadening did not significantly decrease the lidar sensitivity at long paths. (lidars)

Isolation and evaluation of cytogenetic effect of Brahmi saponins on cultured human lymphocytes exposed in vitro.

PubMed

Kalachaveedu, Mangathayaru; Papacchan, Sunu; Sanyal, Sudip; Koshy, Teena; Telapolu, Srivani

2015-01-01

Major saponins of Brahmi (Bacopa monniera, Fam: Scrophulariaceae) - bacosides A and B - were isolated from the total methanol extract and characterised based on melting point, TLC, IR, (1)H NMR and (13)C NMR. They were evaluated for their in vitro cytogenetic effects on human peripheral blood lymphocytes by chromosomal aberration (CA) assay and sister chromatid exchange (SCE) assay. The frequency of chromatid type aberrations and reciprocal interchanges between sister chromatids in the treated cells was scored in comparison to the untreated control. At 30 μg/mL dose, bacoside A showed a statistically significant increase in the frequency of both CA and SCE and bacoside B showed an increase only in SCE. Our report of the genotoxicity of the saponins is significant in view of the reports of anticancer activity of Brahmi extracts.

Heart rate variability and hemodynamic change in the superior mesenteric artery by acupuncture stimulation of lower limb points: a randomized crossover trial.

PubMed

Kaneko, Soichiro; Watanabe, Masashi; Takayama, Shin; Numata, Takehiro; Seki, Takashi; Tanaka, Junichi; Kanemura, Seiki; Kagaya, Yutaka; Ishii, Tadashi; Kimura, Yoshitaka; Yaegashi, Nobuo

2013-01-01

Objective. We investigated the relationship between superior mesenteric artery blood flow volume (SMA BFV) and autonomic nerve activity in acupuncture stimulation of lower limb points through heart rate variability (HRV) evaluations. Methods. Twenty-six healthy volunteers underwent crossover applications of bilateral manual acupuncture stimulation at ST36 or LR3 or no stimulation. Heart rate, blood pressure, cardiac index, systemic vascular resistance index, SMA BFV, and HRV at rest and 30 min after the intervention were analyzed. Results. SMA BFV showed a significant increase after ST36 stimulation (0% to 14.1% ± 23.4%, P = 0.007); very low frequency (VLF), high frequency (HF), low frequency (LF), and LF/HF were significantly greater than those at rest (0% to 479.4% ± 1185.6%, P = 0.045; 0% to 78.9% ± 197.6%, P = 0.048; 0% to 123.9% ± 217.1%, P = 0.006; 0% to 71.5% ± 171.1%, P = 0.039). Changes in HF and LF also differed significantly from those resulting from LR3 stimulation (HF: 78.9% ± 197.6% versus -18.2% ± 35.8%, P = 0.015; LF: 123.9% ± 217.1% versus 10.6% ± 70.6%, P = 0.013). Conclusion. Increased vagus nerve activity after ST36 stimulation resulted in increased SMA BFV. This partly explains the mechanism of acupuncture-induced BFV changes.

Heart Rate Variability and Hemodynamic Change in the Superior Mesenteric Artery by Acupuncture Stimulation of Lower Limb Points: A Randomized Crossover Trial

PubMed Central

Watanabe, Masashi; Tanaka, Junichi; Kanemura, Seiki; Kagaya, Yutaka; Ishii, Tadashi; Kimura, Yoshitaka; Yaegashi, Nobuo

2013-01-01

Objective. We investigated the relationship between superior mesenteric artery blood flow volume (SMA BFV) and autonomic nerve activity in acupuncture stimulation of lower limb points through heart rate variability (HRV) evaluations. Methods. Twenty-six healthy volunteers underwent crossover applications of bilateral manual acupuncture stimulation at ST36 or LR3 or no stimulation. Heart rate, blood pressure, cardiac index, systemic vascular resistance index, SMA BFV, and HRV at rest and 30 min after the intervention were analyzed. Results. SMA BFV showed a significant increase after ST36 stimulation (0% to 14.1% ± 23.4%, P = 0.007); very low frequency (VLF), high frequency (HF), low frequency (LF), and LF/HF were significantly greater than those at rest (0% to 479.4% ± 1185.6%, P = 0.045; 0% to 78.9% ± 197.6%, P = 0.048; 0% to 123.9% ± 217.1%, P = 0.006; 0% to 71.5% ± 171.1%, P = 0.039). Changes in HF and LF also differed significantly from those resulting from LR3 stimulation (HF: 78.9% ± 197.6% versus −18.2% ± 35.8%, P = 0.015; LF: 123.9% ± 217.1% versus 10.6% ± 70.6%, P = 0.013). Conclusion. Increased vagus nerve activity after ST36 stimulation resulted in increased SMA BFV. This partly explains the mechanism of acupuncture-induced BFV changes. PMID:24381632

Effects of breathing frequency and flow rate on the total inward leakage of an elastomeric half-mask donned on an advanced manikin headform.

PubMed

He, Xinjian; Grinshpun, Sergey A; Reponen, Tiina; McKay, Roy; Bergman, Michael S; Zhuang, Ziqing

2014-03-01

The objective of this study was to investigate the effects of breathing frequency and flow rate on the total inward leakage (TIL) of an elastomeric half-mask donned on an advanced manikin headform and challenged with combustion aerosols. An elastomeric half-mask respirator equipped with P100 filters was donned on an advanced manikin headform covered with life-like soft skin and challenged with aerosols originated by burning three materials: wood, paper, and plastic (polyethylene). TIL was determined as the ratio of aerosol concentrations inside (C in) and outside (C out) of the respirator (C in/C out) measured with a nanoparticle spectrometer operating in the particle size range of 20-200nm. The testing was performed under three cyclic breathing flows [mean inspiratory flow (MIF) of 30, 55, and 85 l/min] and five breathing frequencies (10, 15, 20, 25, and 30 breaths/min). A completely randomized factorial study design was chosen with four replicates for each combination of breathing flow rate and frequency. Particle size, MIF, and combustion material had significant (P < 0.001) effects on TIL regardless of breathing frequency. Increasing breathing flow decreased TIL. Testing with plastic aerosol produced higher mean TIL values than wood and paper aerosols. The effect of the breathing frequency was complex. When analyzed using all combustion aerosols and MIFs (pooled data), breathing frequency did not significantly (P = 0.08) affect TIL. However, once the data were stratified according to combustion aerosol and MIF, the effect of breathing frequency became significant (P < 0.05) for all MIFs challenged with wood and paper combustion aerosols, and for MIF = 30 l/min only when challenged with plastic combustion aerosol. The effect of breathing frequency on TIL is less significant than the effects of combustion aerosol and breathing flow rate for the tested elastomeric half-mask respirator. The greatest TIL occurred when challenged with plastic aerosol at 30 l/min and at a breathing frequency of 30 breaths/min.

The diuretic effect in human subjects of an extract of Taraxacum officinale folium over a single day.

PubMed

Clare, Bevin A; Conroy, Richard S; Spelman, Kevin

2009-08-01

Taraxacum officinale (L.) Weber (Asteraceae) has been extensively employed as a diuretic in traditional folk medicine and in modern phytotherapy in Europe, Asia, and the Americas without prior clinical trial substantiation. In this pilot study, a high-quality fresh leaf hydroethanolic extract of the medicinal plant T. officinale (dandelion) was ingested by volunteers to investigate whether an increased urinary frequency and volume would result. Volume of urinary output and fluid intake were recorded by subjects. Baseline values for urinary frequency and excretion ratio (urination volume:fluid intake) were established 2 days prior to dandelion dosing (8 mL TID) and monitored throughout a 1-day dosing period and 24 hours postdosing. For the entire population (n = 17) there was a significant (p < 0.05) increase in the frequency of urination in the 5-hour period after the first dose. There was also a significant (p < 0.001) increase in the excretion ratio in the 5-hour period after the second dose of extract. The third dose failed to change any of the measured parameters. Based on these first human data, T. officinale ethanolic extract shows promise as a diuretic in humans. Further studies are needed to establish the value of this herb for induction of diuresis in human subjects.

Subtitle-Based Word Frequencies as the Best Estimate of Reading Behavior: The Case of Greek

PubMed Central

Dimitropoulou, Maria; Duñabeitia, Jon Andoni; Avilés, Alberto; Corral, José; Carreiras, Manuel

2010-01-01

Previous evidence has shown that word frequencies calculated from corpora based on film and television subtitles can readily account for reading performance, since the language used in subtitles greatly approximates everyday language. The present study examines this issue in a society with increased exposure to subtitle reading. We compiled SUBTLEX-GR, a subtitled-based corpus consisting of more than 27 million Modern Greek words, and tested to what extent subtitle-based frequency estimates and those taken from a written corpus of Modern Greek account for the lexical decision performance of young Greek adults who are exposed to subtitle reading on a daily basis. Results showed that SUBTLEX-GR frequency estimates effectively accounted for participants’ reading performance in two different visual word recognition experiments. More importantly, different analyses showed that frequencies estimated from a subtitle corpus explained the obtained results significantly better than traditional frequencies derived from written corpora. PMID:21833273

Handling of peripheral intravenous cannulae: effects of evidence-based clinical guidelines.

PubMed

Ahlqvist, Margary; Bogren, Agneta; Hagman, Sari; Nazar, Isabel; Nilsson, Katarina; Nordin, Karin; Valfridsson, Berit Sunde; Söderlund, Mona; Nordström, Gun

2006-11-01

This study aimed at evaluating the outcome of implemented evidence-based clinical guidelines by means of surveying the frequency of thrombophlebitis, nurses' care, handling and documentation of peripheral intravenous cannulae. Peripheral intravenous cannulae are frequently used for vascular access and, thereby, the patients will be exposed to local and systemic infectious complications. Evidence-based knowledge of how to prevent these complications and how to care for patients with peripheral intravenous cannula is therefore of great importance. Deficient care, handling and documentation of peripheral intravenous cannulae have previously been reported. A cross-sectional survey was conducted by a group of nurses at three wards at a university hospital before and after the implementation of the evidence-based guidelines. A structured observation protocol was used to review the frequency of thrombophlebitis, the nurses' care, handling and the documentation of peripheral intravenous cannulae in the patient's record. A total of 107 and 99 cannulae respectively were observed before and after the implementation of the guidelines. The frequency of peripheral intravenous cannulae without signs of thrombophlebitis increased by 21% (P < 0.01) and the use of cannula size 0.8 mm increased by 22% (P < 0.001). Nurses' documentation of peripheral intravenous cannula improved significantly (P < 0.001). We conclude that implementation of the guidelines resulted in significant improvements by means of decreased frequency of signs of thrombophlebitis, increased application of smaller cannula size (0.8 mm), as well as of the nurses' documentation in the patient's record. Further efforts to ameliorate care and handling of peripheral intravenous cannulae are needed. This can be done by means of increasing nurses' knowledge and recurrent quality reviews. Well-informed patients can also be more involved in the care than is common today.

Mismatch repair gene MSH3 polymorphism is associated with the risk of sporadic prostate cancer.

PubMed

Hirata, Hiroshi; Hinoda, Yuji; Kawamoto, Ken; Kikuno, Nobuyuki; Suehiro, Yutaka; Okayama, Naoko; Tanaka, Yuichiro; Dahiya, Rajvir

2008-05-01

The mismatch repair system is a DNA repair mechanism that corrects mispaired bases during DNA replication errors. Cancer cells deficient in MMR proteins have a 10(2) to 10(3)-fold increase in the mutation rate. Single nucleotide polymorphisms of mismatch repair genes have been shown to cause a decrease in DNA repair activity. We hypothesized that mismatch repair gene polymorphism could be a risk factor for prostate cancer and p53 Pro/Pro genotype carriers could influence MSH3 and MSH6 polymorphisms. DNA samples from 110 patients with prostate cancer and 110 healthy controls were analyzed by single strand conformational polymorphism and polymerase chain reaction-restriction fragment length polymorphism to determine the genotypic frequency of 5 polymorphic loci on 2 MMR genes (MSH3 and MSH6) and p53 codon72. The chi-square test was applied to compare genotype frequency between patients and controls. A significant increase in the G/A+A/A genotype of MSH3 Pro222Pro was observed in patients compared to controls (OR 1.87, 95% CI 1.0-3.5). The frequency of A/G + G/G genotypes of MSH3 exon23 Thr1036Ala also tended to increase in patients (OR 1.57, 95% CI 0.92-2.72). In p53 codon72 Arg/Pro + Pro/Pro carriers the frequency of the AG + GG genotype of MSH3 exon23 was significantly increased in patients compared to controls (OR 2.1, 95% CI 1.05-4.34). To our knowledge this is the first report of the association of MSH3 gene polymorphisms in prostate cancer. These results suggest that the MSH3 polymorphism may be a risk factor for prostate cancer.

Mismatch repair gene MSH3 polymorphism is associated with the risk of sporadic prostate cancer

PubMed Central

Hirata, Hiroshi; Hinoda, Yuji; Kawamoto, Ken; Kikuno, Nobuyuki; Suehiro, Yutaka; Okayama, Naoko; Tanaka, Yuichiro; Dahiya, Rajvir

2014-01-01

Purpose The mismatch repair (MMR) system is a DNA repair mechanism that corrects mispaired bases during DNA replication errors. Cancer cells deficient in the MMR proteins have a 102 –103-fold increase in the mutation rate. Single nucleotide polymorphisms (SNPs) of MMR genes have been shown to cause a reduction in DNA repair activity. We hypothesized that mismatch repair gene polymorphism could be a risk factor for prostate cancer (PC) and that p53 Pro/Pro genotype carriers could influence MSH3 and MSH6 polymorphisms. Material and Methods DNA samples from 110 cases of prostate cancer and healthy controls (n=110) were analyzed by SSCP and PCR-RFLP to determine the genotypic frequency of five different polymorphic loci on two MMR genes (MSH3 and MSH6) and p53 codon72. The chi-square test was applied to compare the genotype frequency between patients and controls. Results A significant increase in the G/A+A/A genotype of MSH3 Pro222Pro was observed in patients compared to controls (OR, 1.87; 95% CI, 1.0–3.5). The frequency of A/G + G/G genotypes of MSH3 exon23 Thr1036Ala also tended to increase in patients (OR, 1.57; 95% CI, 0.92–2.72). Among p53 codon72 Arg/Pro + Pro/Pro carriers, the frequency of the AG + GG genotype of MSH3 exon23 was significantly increased in patients compared to controls (OR = 2.1, 95% CI; 1.05–4.34). Conclusion This is the first report on the association of MSH3 gene polymorphisms in prostate cancer. These results suggest that the MSH3 polymorphism may be a risk factor for prostate cancer. PMID:18355840

Future changes of precipitation characteristics in China

NASA Astrophysics Data System (ADS)

Wu, S.; Wu, Y.; Wen, J.

2017-12-01

Global warming has the potential to alter the hydrological cycle, with significant impacts on the human society, the environment and ecosystems. This study provides a detailed assessment of potential changes in precipitation characteristics in China using a suite of 12 high-resolution CMIP5 climate models under a medium and a high Representative Concentration Pathways: RCP4.5 and RCP8.5. We examine future changes over the entire distribution of precipitation, and identify any shift in the shape and/or scale of the distribution. In addition, we use extreme-value theory to evaluate the change in probability and magnitude for extreme precipitation events. Overall, China is going to experience an increase in total precipitation (by 8% under RCP4.5 and 12% under RCP8.5). This increase is uneven spatially, with more increase in the west and less increase in the east. Precipitation frequency is projected to increase in the west and decrease in the east. Under RCP4.5, the overall precipitation frequency for the entire China remains largely unchanged (0.08%). However, RCP8.5 projects a more significant decrease in frequency for large part of China, resulting in an overall decrease of 2.08%. Precipitation intensity is likely increase more uniformly, with an overall increase of 11% for RCP4.5 and 19% for RCP8.5. Precipitation increases for all parts of the distribution, but the increase is more for higher quantiles, i.e. strong events. The relative contribution of small quantiles is likely to decrease, whereas contribution from heavy events is likely to increase. Extreme precipitation increase at much higher rates than average precipitation, and high rates of increase are expected for more extreme events. 1-year events are likely to increase by 15%, but 20-year events are going to increase by 21% under RCP4.5, 26% and 40% respectively under RCP8.5. The increase of extreme events is likely to be more spatially uniform.

SHI induced modification in structural, optical, dielectric and thermal properties of poly ethylene oxide films

NASA Astrophysics Data System (ADS)

Patel, Gnansagar B.; Bhavsar, Shilpa; Singh, N. L.; Singh, F.; Kulriya, P. K.

2016-07-01

Poly ethylene oxide (PEO) films were synthesized by solution cast method. These self-standing films were exposed with 60 MeV C+5 ion and 100 MeV Ni+7 ion at different fluences. SHI induced effect was investigated by employing various techniques. The crystalline size decreased upon irradiation as observed from XRD analysis. FTIR analysis reveals the decrement in the peak intensity upon irradiation. Tauc's method was used to determine the optical band gap (Eg), which shows decreasing trends with increase of fluence. The dielectric properties were investigated in the frequency range 10 Hz to 10 MHz for unirradiated and irradiated films. The dielectric constant remains same for the broad-spectrum of frequency and increases at lower frequency. The dielectric loss also moderately influence as a function of frequency due to irradiation. DSC analysis validated the results of XRD. Scanning electron microscopy (SEM) reveals that there is significant change in the surface morphology due to irradiation.

Relationship between frequency of hypoglycemic episodes and changes in carotid atherosclerosis in insulin-treated patients with type 2 diabetes mellitus.

PubMed

Mita, Tomoya; Katakami, Naoto; Shiraiwa, Toshihiko; Yoshii, Hidenori; Kuribayashi, Nobuichi; Osonoi, Takeshi; Kaneto, Hideaki; Kosugi, Keisuke; Umayahara, Yutaka; Gosho, Masahiko; Shimomura, Iichiro; Watada, Hirotaka

2017-01-09

The effect of hypoglycemia on the progression of atherosclerosis in patients with type 2 diabetes mellitus (T2DM) remains largely unknown. This is a post hoc analysis of a randomized trial to investigate the relationship between hypoglycemic episodes and changes in carotid intima-media thickness (IMT). Among 274 study subjects, 104 patients experienced hypoglycemic episodes. Increases in the mean IMT and left maximum IMT of the common carotid arteries (CCA) were significantly greater in patients with hypoglycemia compared to those without hypoglycemia. Classification of the patients into three groups according to the frequency of hypoglycemic episodes showed that high frequency of hypoglycemic events was associated with increases in mean IMT-CCA, and left max-IMT-CCA and right max-IMT-CCA. In addition, repetitive episodes of hypoglycemia were associated with a reduction in the beneficial effects of sitagliptin on carotid IMT. Our data suggest that frequency of hypoglycemic episodes was associated with changes in carotid atherosclerosis.

The effects of ion channel blockers validate the conductance-based model of saccadic oscillations

PubMed Central

Shaikh, Aasef G.; Zee, David S.; Optican, Lance M.; Miura, Kenichiro; Ramat, Stefano; Leigh, R. John

2012-01-01

Conductance-based models of reciprocally inhibiting burst neurons suggest that intrinsic membrane properties and postinhibitory rebound (PIR) determine the amplitude and frequency of saccadic oscillations. Reduction of the low-threshold calcium currents (IT) in the model decreased the amplitude but increased the frequency of the simulated oscillations. Combined reduction of hyperpolarization-activated cation current (Ih) and IT in the model abolished the simulated oscillations. We measured the effects of a selective blocker of IT (ethosuximide) in healthy subjects on the amplitude and frequency of saccadic oscillations evoked by eye closure and of a nonselective blocker of Ih and IT (propronolol) in a patient with microsaccadic oscillation and limb tremor syndrome (mSOLT). Ethosuximide significantly reduced the amplitude but increased the frequency of the saccadic oscillations during eye closure in healthy subjects. Propranolol abolished saccadic oscillations in the mSOLT patient. These results support the hypothetical role of postinhibitory rebound, Ih, and IT, in generation of saccadic oscillations and determining their kinematic properties. PMID:21950976

A longitudinal study of ego identity development at a liberal arts college.

PubMed

Waterman, A S; Goldman, J A

1976-12-01

Ego identity development in the areas of occupational choice, religion, and political ideology was studied using Marcia's categorization system. The results indicated a significant increase in the frequency of the identity achiever status for occupational choice and corresponding decreases in the frequency of the moratorium and identity diffusion statuses. A significant decrease in the frequency of foreclosures on religion was also found. In those instances where students underwent an identity crisis, the probability of resolving it successfully was very high. High scores on the Cultural Sophistication scale of the College Student Questionnaire-Part 1 were found to be associated with presence in the identity achievement status. For students not in the achiever status as freshmen, an interest in various literary and art forms was predictive of becoming an achiever while in college.

Cleaning frequency and the microbial load in ice-cream.

PubMed

Holm, Sonya; Toma, Ramses B; Reiboldt, Wendy; Newcomer, Chris; Calicchia, Melissa

2002-07-01

This study investigates the efficacy of a 62 h cleaning frequency in the manufacturing of ice-cream. Various product and product contact surfaces were sampled progressively throughout the time period between cleaning cycles, and analyzed for microbial growth. The coliform and standard plate counts (SPC) of these samples did not vary significantly over time after 0, 24, 48, or 62 h from Cleaning in Place (CiP). Data for product contact surfaces were significant for the SPC representing sample locations. Some of the variables in cleaning practices had significant influence on microbial loads. An increase in the number of flavors manufactured caused a decrease in SPC within the 24 h interval, but by the 48 h interval the SPC increased. More washouts within the first 24 h interval were favorable, as indicated by decreased SPC. The more frequently the liquefier was sanitized within the 62 h interval, the lower the SPC. This study indicates that food safety was not compromised and safety practices were effectively implemented throughout the process.

Task-specific recruitment of motor units for vibration damping.

PubMed

Wakeling, James M; Liphardt, Anna-Maria

2006-01-01

Vibrations occur within the soft tissues of the lower extremities due to the heel-strike impact during walking. Increases in muscle activity in the lower extremities result in increased damping to reduce this vibration. The myoelectric intensity spectra were compared using principal component analysis from the tibialis anterior and lateral gastrocnemius of 40 subjects walking with different shoe conditions. The soft insert condition resulted in a significant, simultaneous increase in muscle activity with a shift to higher myoelectric frequencies in the period 0-60 ms after heel-strike which is the period when the greater vibration damping occurred. These increases in myoelectric frequency match the spectral patterns which indicate increases in recruitment of faster motor units. It is concluded that fast motor units are recruited during the task of damping the soft-tissue resonance that occurs following heel-strike.

Sloshing response of a reactor tank with internals

NASA Astrophysics Data System (ADS)

Ma, D. C.; Gvildys, J.; Chang, Y. W.

The sloshing response of a large reactor tank with in tank components is presented. It is indicated that the presence of the internal components can significantly change the dynamic characteristics of the sloshing motion. The sloshing frequency of a tank with internals is considerably higher than that of a tank without internal. The higher sloshing frequency reduces the sloshing wave height on the free surface but increases the dynamic pressure in the fluid.

Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models.

PubMed

Song, Hui; Yuan, Xiaoyong; Tang, Xin

2016-01-11

In this study, the effects of intraocular lenses (IOLs) with different diopters (D) on chromatic aberration were investigated in human eye models, and the influences of the central thickness of IOLs on chromatic aberration were compared. A Liou-Brennan-based IOL eye model was constructed using ZEMAX optical design software. Spherical IOLs with different diopters (AR40e, AMO Company, USA) were implanted; modulation transfer function (MTF) values at 3 mm of pupil diameter and from 0 to out-of-focus blur were collected and graphed. MTF values, measured at 555 nm of monochromatic light under each spatial frequency, were significantly higher than the values measured at 470 to 650 nm of polychromatic light. The influences of chromatic aberration on MTF values decreased with the increase in IOL diopter when the spatial frequency was ≤12 c/d, while increased effects were observed when the spatial frequency was ≥15 c/d. The MTF values of each IOL eye model were significantly lower than the MTF values of the Liou-Brennan eye models when measured at 555 nm of monochromatic light and at 470 to 650 nm of polychromatic light. The MTF values were also found to be increased with the increase in IOL diopter. With higher diopters of IOLs, the central thickness increased accordingly, which could have created increased chromatic aberration and decreased the retinal image quality. To improve the postoperative visual quality, IOLs with lower chromatic aberration should be selected for patients with short axial lengths.

Effect of feeding frequency on growth, body composition, antioxidant status and mRNA expression of immunodependent genes before or after ammonia-N stress in juvenile oriental river prawn, Macrobrachium nipponense.

PubMed

Ding, Zhili; Kong, Youqin; Zhang, Yixiang; Li, Jingfen; Cao, Fang; Zhou, Junbo; Ye, Jinyun

2017-09-01

Feeding frequency is important for the improvement of growth performance and immunity of aquatic animals. In this study, the effect of feeding frequency on growth, body composition, antioxidant status and mRNA expression of immunodependent genes before or after ammonia-N stress was examined in Macrobrachium nipponense. Prawns were randomly assigned to one of five feeding frequencies (1, 2, 3, 4 and 6 times/day) following the same ration size over an 8-week growth trial. After the feeding trial, prawns were challenged by ammonia-N. The weight gain of prawns fed with 3-6 times/day was significantly higher than that of prawns fed with 1 time/day. The best feed conversion ratio was obtained from prawns fed with 3-6 times/day. Body crude lipid with feeding frequency of 3, 4 or 6 times/day was quite lower than that with 1 time/day. High feeding frequency (6 times/day) induced significantly elevated hepatopancreas super oxide dismutase and catalase activities. The malondialdehyde level in prawns fed with 6 times/day was also significantly increased, which was higher than that of prawns fed with other feeding frequency. mRNA expression of toll like receptor 3 and myeloid differentiation primary response protein MyD88 was promoted by feeding frequency from 3 to 4 time/day but inhibited by high or low feeding frequency. Similar mRNA expression variation trends of the two genes were observed in prawns after ammonia-N stress. After ammonia-N challenge, the highest cumulative mortality was observed in prawns fed with 6 times/day, which was significantly higher than that of prawns fed with 2-4 times/day. These findings demonstrate that (1) too high feeding frequency induced oxidative stress and malondialdehyde accumulation, negatively affecting the health status of prawns and reduced its resistance to ammonia-N stress; (2) the optimal feeding frequency to improve growth and immune response of this species at juvenile stage is 3-4 times/day; (3) considering costs of labour, a feeding frequency of 3 times/day is recommended for this prawn. Copyright © 2017 Elsevier Ltd. All rights reserved.

Association of Physical Exercise on Anxiety and Depression Amongst Adults.

PubMed

Khanzada, Faizan Jameel; Soomro, Nabila; Khan, Shahidda Zakir

2015-07-01

This study was done to determine the frequency of anxiety, depression among those who exercise regularly and those who do not. Across-sectional study was conducted at different gymnasiums of Karachi in July-August 2013. A total 269 individual's ages were 18 - 45 years completed a self-administered questionnaire to assess the data using simple descriptive statistics. One hundred and thirty four individuals were those who did not perform exercise which included females (55.0%) being more frequently anxious than male (46.4%). Females (39.9%) were more frequently depressed as compared to males (26.4%) less depressed. Chi-square test showed association between anxiety levels and exercise was significantly increased in non-exercisers compared to regular exercisers found to be significant (p=0.015). Individuals who performed regular exercise had a lower frequency of depression (28.9%) than non-exercisers (41.8%). Physical exercise was significantly associated with lower anxiety and depression frequency amongst the studied adult population.

Exercise training improves autonomic profiles in patients with Charcot-Marie-Tooth disease.

PubMed

El Mhandi, Lhassan; Pichot, Vincent; Calmels, Paul; Gautheron, Vincent; Roche, Frédéric; Féasson, Léonard

2011-11-01

The effect of an interval exercise training (ITE) program on heart rate variability (HRV) was studied in 8 patients with Charcot-Marie-Tooth (CMT) disease and 8 healthy controls. At baseline, all subjects underwent ambulatory 24-hour Holter electrocardiographic (ECG) monitoring to evaluate HRV. HRV analysis was repeated on CMT patients after they completed a 24-week ITE program on a cycle ergometer. Before exercise, all HRV indices were lower in patients compared with controls, and the difference reached statistical significance for pNN50 (percent of differences between adjacent R-R intervals exceeding 50 ms). After ITE, time- and frequency-domain indices were significantly improved, particularly at night (+8% mean R-R interval, +95% pNN50, 52% reduction in low/high-frequency ratio). We observed significant increases in some of the time and frequency parameters, and values sometimes exceeded those of controls at baseline. Our results suggest that ITE improves HRV modulation in CMT patients by enhancing parasympathetic activity. Copyright © 2011 Wiley Periodicals, Inc.