Behavioral cross-sensitization between DOCA-induced sodium appetite and cocaine-induced locomotor behavior

PubMed Central

Acerbo, Martin J.; Johnson, Alan Kim

2011-01-01

Behavioral sensitization involves increases in the magnitude of a response to a stimulus after repeated exposures to the same response initiator. Administration of psychomotor stimulants and the induction of appetitive motivational states associated with natural reinforcers like sugar and salt are among experimental manipulations producing behavioral sensitization. In rats, repeated administration of the mineralocorticoid agonist deoxycorticosterone acetate (DOCA) initially induces incremental increases in daily hypertonic saline consumption (i.e., sensitization of sodium appetite) in spite of the retention of sodium. The present studies investigated whether sodium appetite sensitization induced by DOCA shares mechanisms similar to those of psychomotor stimulant-induced sensitization, and whether there is evidence for reciprocal cross-sensitization. In Experiments 1 and 3, rats received control or cocaine treatments to induce locomotor sensitization. A week later DOCA (or vehicle) was administered to generate a sodium appetite. Animals pretreated with cocaine showed a greater sodium appetite. In Experiment 2, the order of the putative sensitizing treatments was reversed. Rats first received either a series of DOCA or vehicle treatments either with or without access to saline and were later tested for sensitization of the locomotor response to cocaine. Animals pretreated with DOCA without access to saline showed greater locomotor responses to cocaine than animals receiving vehicle treatments. Together these experiments indicate that treatments generating a sustained salt appetite and producing cocaine-induced psychomotor responses show reciprocal behavioral cross-sensitization. The underlying mechanisms accounting for this relationship may be the fact that psychostimulants and an unresolved craving for sodium can act as potent stressors. PMID:21352848

Monte Carlo sensitivity analysis of land surface parameters using the Variable Infiltration Capacity model

NASA Astrophysics Data System (ADS)

Demaria, Eleonora M.; Nijssen, Bart; Wagener, Thorsten

2007-06-01

Current land surface models use increasingly complex descriptions of the processes that they represent. Increase in complexity is accompanied by an increase in the number of model parameters, many of which cannot be measured directly at large spatial scales. A Monte Carlo framework was used to evaluate the sensitivity and identifiability of ten parameters controlling surface and subsurface runoff generation in the Variable Infiltration Capacity model (VIC). Using the Monte Carlo Analysis Toolbox (MCAT), parameter sensitivities were studied for four U.S. watersheds along a hydroclimatic gradient, based on a 20-year data set developed for the Model Parameter Estimation Experiment (MOPEX). Results showed that simulated streamflows are sensitive to three parameters when evaluated with different objective functions. Sensitivity of the infiltration parameter (b) and the drainage parameter (exp) were strongly related to the hydroclimatic gradient. The placement of vegetation roots played an important role in the sensitivity of model simulations to the thickness of the second soil layer (thick2). Overparameterization was found in the base flow formulation indicating that a simplified version could be implemented. Parameter sensitivity was more strongly dictated by climatic gradients than by changes in soil properties. Results showed how a complex model can be reduced to a more parsimonious form, leading to a more identifiable model with an increased chance of successful regionalization to ungauged basins. Although parameter sensitivities are strictly valid for VIC, this model is representative of a wider class of macroscale hydrological models. Consequently, the results and methodology will have applicability to other hydrological models.

Susceptibility of Nontypeable Haemophilus influenzae to Human β-Defensins Is Influenced by Lipooligosaccharide Acylation

PubMed Central

Starner, Timothy D.; Swords, W. Edward; Apicella, Michael A.; McCray, Paul B.

2002-01-01

Nontypeable Haemophilus influenzae (NTHI) lipooligosaccharide htrB mutants exhibited greater than 45-fold-increased sensitivity to human β-defensin 2 (HBD-2) compared to the wild type. Complementation by htrB in trans to acylation competence reversed this increased sensitivity. In contrast, NTHI was more susceptible to HBD-3 and showed no changes in sensitivity as a result of lipooligosaccharide mutations in oligosaccharide and lipid A biosynthesis genes. PMID:12183584

Acid-sensitive sheddable PEGylated, mannose-modified nanoparticles increase the delivery of betamethasone to chronic inflammation sites in a mouse model

PubMed Central

O’Mary, Hannah L.; Aldayel, Abdulaziz M.; Valdes, Solange A.; Naguib, Youssef W.; Li, Xu; Salvady, Karun; Cui, Zhengrong

2017-01-01

Inflammation is implicated in a host of chronic illnesses. Within these inflamed tissues, the pH of the microenvironment is decreased and immune cells, particularly macrophages, infiltrate the area. Additionally, the vascular integrity of these sites is altered with increased fenestrations between endothelial cells. These distinctive properties may be exploited to enhance targeted delivery of anti-inflammatory therapies. Using a mouse model of chronic inflammation, we previously showed that acid-sensitive sheddable PEGylation increases the distribution and retention of nanoparticles in chronic inflammation sites. Here we demonstrated that surface modification of the acid-sensitive sheddable PEGylated nanoparticles with mannose, a ligand to mannose receptors present in chronic inflammation sites, significantly increases the targeted delivery of the nanoparticles to these areas. Furthermore, we showed that the acid-sensitive sheddable PEGylated, mannose-modified nanoparticles are able to significantly increase the delivery of betamethasone-21-acetate (BA), a model anti-inflammatory compound, to chronic inflammation sites as compared to free BA. These results highlight the ability to engineer formulations to target chronic inflammation sites by exploiting the microenvironment of these regions. PMID:28463518

Effects of prolonged abstinence from METH on the hippocampal BDNF levels, neuronal numbers and apoptosis in methamphetamine-sensitized rats.

PubMed

Hajheidari, Samira; Sameni, Hamid Reza; Bandegi, Ahmad Reza; Miladi-Gorji, Hossein

2017-04-03

Methamphetamine (METH) use is associated with neuronal damage in various regions of brain, while effects of prolonged abstinence on METH-induced damage are not quite clear. This study evaluated serum and hippocampal BDNF levels, neuronal numbers and apoptosis in METH-sensitized and abstinent rats. Rats were sensitized to METH (2mg/kg, daily/18 days, s.c.). All rats were evaluated for neuron counting, the TUNEL test and serum and hippocampal BDNF levels after 30 days of forced abstinence from METH. The results showed that increased BDNF levels in the hippocampus and serum of METH-sensitized rats returned to control level after 30 days of abstinence. The number of neurons in the DG and CA1 of hippocampus and also, the total hippocampal perimeter and area in METH-sensitized rats were significantly lower than the saline rats. While, the number of neurons was not significantly increased in the hippocampus after prolonged abstinence from METH. Also, METH-sensitized rats showed a significant increase in TUNEL-positive cells, whereas METH-abstinent rats showed a slight but significant decrease in TUNEL-positive cells in the DG and CA3 of hippocampus. These results suggest that despite the reduction in BDNF levels, reducing the number of neurons, perimeter and area of the hippocampus were stable after abstinence. Thus, the degenerative effects of METH have been sustained even after prolonged abstinence in the hippocampus. Copyright © 2017 Elsevier B.V. All rights reserved.

Terahertz absorber based on Fano-like resonance of inverted quadrangular frustum pyramid metal grooves and sensor application

NASA Astrophysics Data System (ADS)

Yu, Yingying; Sun, Bo

2018-07-01

We investigate the multi-resonance coupling of inverted quadrangular frustum pyramid (IQFP) groove metal arrays at terahertz frequencies. The surface plasmon resonance (SPR) and groove resonance are induced, resulting in resonance coupling. The dipole of the groove resonance drives the quadrupole of the SPR and creates a sharp Fano-like resonance. The effects of geometry parameters including the width (at the bottom) and height are analyzed in detail. The results show that with the decrease in the sidewall slope of the groove, the confinement of the groove region on the electromagnetic field decreases, thereby increasing the resonance coupling. The Fano-like resonance is enhanced. The sensitivity and quality factor are discussed. The results show that the Fano-like resonance has high sensitivity and quality factor. With the increase in the sidewall slope of the groove, the sensitivity increases, and the quality factor decreases. The results show that the Fano-like resonance of IQFP groove metal arrays has a significant potential for biological monitoring and sensing.

Exploring the Relationship Between Octane Sensitivity and Heat-of-Vaporization

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

Sluder, C. Scott; Szybist, James P.; McCormick, Robert L.

2016-04-05

The latent heat-of-vaporization (HoV) of blends of biofuel and hydrocarbon components into gasolines has recently experienced expanded interest because of the potential for increased HoV to increase fuel knock resistance in direct-injection (DI) engines. Several studies have been conducted, with some studies identifying an additional anti-knock benefit from HoV and others failing to arrive at the same conclusion. Consideration of these studies holistically shows that they can be grouped according to the level of fuel octane sensitivity variation within their fuel matrices. When comparing fuels of different octane sensitivity significant additional anti-knock benefits associated with HoV are sometimes observed. Studiesmore » that fix the octane sensitivity find that HoV does not produce additional anti-knock benefit. New studies were performed at ORNL and NREL to further investigate the relationship between HoV and octane sensitivity. Three fuels were formulated for the ORNL study with matched RON and octane sensitivity, but with differing HoV. Experiments with these fuels in a 1.6-liter GTDI engine showed that the fuels exhibited very similar combustion phasing under knock-limited spark advance (KLSA) conditions. Fuels having a range of RON, octane sensitivity, and HoV were tested at NREL in a single-cylinder GDI engine under conditions where octane sensitivity has little effect on knock resistance. KLSA was found to be well correlated with RON. These results reinforce the concept that HoV anti-knock effects can be viewed as a contributor to octane sensitivity. From this viewpoint, HoV effects manifest themselves as increases in octane sensitivity.« less

In Sickness and in Health: The Co-Regulation of Inflammation and Social Behavior

PubMed Central

Eisenberger, Naomi I; Moieni, Mona; Inagaki, Tristen K; Muscatell, Keely A; Irwin, Michael R

2017-01-01

Although it has commonly been assumed that the immune system and the processes that govern social behavior are separate, non-communicating entities, research over the past several decades suggests otherwise. Considerable evidence now shows that inflammatory processes and social behavior are actually powerful regulators of one another. This review first summarizes evidence that inflammatory processes regulate social behavior, leading to characteristic changes that may help an individual navigate the social environment during times of sickness. Specifically, this review shows that inflammation: (1) increases threat-related neural sensitivity to negative social experiences (eg, rejection, negative social feedback), presumably to enhance sensitivity to threats to well-being or safety in order to avoid them and (2) enhances reward-related neural sensitivity to positive social experiences (eg, viewing close others and receiving positive social feedback), presumably to increase approach-related motivation towards others who might provide support and care during sickness. Next, this review summarizes evidence showing that social behavior also regulates aspects of inflammatory activity, preparing the body for situations in which wounding and infection may be more likely (social isolation). Here, we review research showing: (1) that exposure to social stressors increases proinflammatory activity, (2) that individuals who are more socially isolated (ie, lonely) show increased proinflammatory activity, and (3) that individuals who are more socially isolated show increased proinflammatory activity in response to an inflammatory challenge or social stressor. The implications of the co-regulation of inflammation and social behavior are discussed. PMID:27480575

Sensitivity to binaural timing in bilateral cochlear implant users.

PubMed

van Hoesel, Richard J M

2007-04-01

Various measures of binaural timing sensitivity were made in three bilateral cochlear implant users, who had demonstrated moderate-to-good interaural time delay (ITD) sensitivity at 100 pulses-per-second (pps). Overall, ITD thresholds increased at higher pulse rates, lower levels, and shorter durations, although intersubject differences were evident. Monaural rate-discrimination thresholds, using the same stimulation parameters, showed more substantial elevation than ITDs with increased rate. ITD sensitivity with 6000 pps stimuli, amplitude-modulated at 100 Hz, was similar to that with unmodulated pulse trains at 100 pps, but at 200 and 300 Hz performance was poorer than with unmodulated signals. Measures of sensitivity to binaural beats with unmodulated pulse-trains showed that all three subjects could use time-varying ITD cues at 100 pps, but not 300 pps, even though static ITD sensitivity was relatively unaffected over that range. The difference between static and dynamic ITD thresholds is discussed in terms of relative contributions from initial and later arriving cues, which was further examined in an experiment using two-pulse stimuli as a function of interpulse separation. In agreement with the binaural-beat data, findings from that experiment showed poor discrimination of ITDs on the second pulse when the interval between pulses was reduced to a few milliseconds.

Mothers' and Fathers' Sensitivity with Their Two Children: A Longitudinal Study from Infancy to Early Childhood

ERIC Educational Resources Information Center

Hallers-Haalboom, Elizabeth T.; Groeneveld, Marleen G.; van Berkel, Sheila R.; Endendijk, Joyce J.; van der Pol, Lotte D.; Linting, Mariëlle; Bakermans-Kranenburg, Marian J.; Mesman, Judi

2017-01-01

To examine the effects of child age and birth order on sensitive parenting, 364 families with 2 children were visited when the second-born children were 12, 24, and 36 months old, and their older siblings were on average 2 years older. Mothers showed higher levels of sensitivity than fathers at all assessments. Parental sensitivity increased from…

Developmental change in children's sensitivity to sound symbolism.

PubMed

Tzeng, Christina Y; Nygaard, Lynne C; Namy, Laura L

2017-08-01

The current study examined developmental change in children's sensitivity to sound symbolism. Three-, five-, and seven-year-old children heard sound symbolic novel words and foreign words meaning round and pointy and chose which of two pictures (one round and one pointy) best corresponded to each word they heard. Task performance varied as a function of both word type and age group such that accuracy was greater for novel words than for foreign words, and task performance increased with age for both word types. For novel words, children in all age groups reliably chose the correct corresponding picture. For foreign words, 3-year-olds showed chance performance, whereas 5- and 7-year-olds showed reliably above-chance performance. Results suggest increased sensitivity to sound symbolic cues with development and imply that although sensitivity to sound symbolism may be available early and facilitate children's word-referent mappings, sensitivity to subtler sound symbolic cues requires greater language experience. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of Propellant Composition to the Temperature Sensitivity of Composite Propellant

NASA Astrophysics Data System (ADS)

Aziz, Amir; Mamat, Rizalman; Amin, Makeen; Ali, Wan Khairuddin Wan

2012-09-01

The propellant composition is one of several parameter that influencing the temperature sensitivity of composite propellant. In this paper, experimental investigation of temperature sensitivity in burning rate of composite propellant was conducted. Four sets of different propellant compositions had been prepared with the combination of ammonium perchlorate (AP) as an oxidizer, aluminum (Al) as fuel and hydroxy-terminated polybutadiene (HTPB) as fuel and binder. For each mixture, HTPB binder was fixed at 15% and cured with isophorone diisocyanate (IPDI). By varying AP and Al, the effect of oxidizer- fuel mixture ratio (O/F) on the whole propellant can be determined. The propellant strands were manufactured using compression molded method and burnt in a strand burner using wire technique over a range of pressure from 1 atm to 31 atm. The results obtained shows that the temperature sensitivity, a, increases with increasing O/F. Propellant p80 which has O/F ratio of 80/20 gives the highest value of temperature sensitivity which is 1.687. The results shows that the propellant composition has significant effect on the temperature sensitivity of composite propellant

Modelling responses of the inert-gas washout and MRI to bronchoconstriction.

PubMed

Foy, Brody H; Kay, David; Bordas, Rafel

2017-01-01

Many lung diseases lead to an increase in ventilation heterogeneity (VH). Two clinical practices for the measurement of patient VH are in vivo imaging, and the inert gas multiple breath washout (MBW). In this study computational modelling was used to compare the responses of MBW indices LCI and s cond and MRI measured global and local ventilation indices, σ r and σ local , to constriction of airways in the conducting zone of the lungs. The simulations show that s cond , LCI and σ r behave quite similarly to each other, all being sensitive to increases in the severity of constriction, while exhibiting little sensitivity to the depth at which constriction occurs. In contrast, the local MRI index σ local shows strong sensitivity to depth of constriction, but lowered sensitivity to constriction severity. We finish with an analysis of the sensitivity of MRI indices to grid sizes, showing that results should be interpreted with reference to the image resolution. Overall we conclude that the application of both local and global VH measures may help to classify different types of bronchoconstriction. Copyright © 2016 Elsevier B.V. All rights reserved.

Motivation from control.

PubMed

Eitam, Baruch; Kennedy, Patrick M; Tory Higgins, E

2013-09-01

Human motivation is sensitive to value-to the outcomes of actions. People invest mental and physical resources for obtaining desired results or for stopping and reversing undesired ones. Accordingly, people's motivation is sensitive to information about their standing in relation to outcome attainment ('outcome feedback'). In this paper, we argue and present the first evidence for the existence of another motivational sensitivity in humans-a sensitivity to our degree of control on the environment and hence to information about that control ('control feedback'). We show that when actions have even trivial and constant perceptual effects, participants' motivation to perform is enhanced. We then show that increased motivation is not because more information about task performance is available and that motivation is increased only in conditions in which control over the effects can be firmly established by the mind. We speculate on the implications for understanding motivation, and potentially, physical and mental health.

Diagnostic accuracy of functional, imaging and biochemical tests for patients presenting with chest pain to the emergency department: A systematic review and meta-analysis.

PubMed

Iannaccone, Mario; Gili, Sebastiano; De Filippo, Ovidio; D'Amico, Salvatore; Gagliardi, Marco; Bertaina, Maurizio; Mazzilli, Silvia; Rettegno, Sara; Bongiovanni, Federica; Gatti, Paolo; Ugo, Fabrizio; Boccuzzi, Giacomo G; Colangelo, Salvatore; Prato, Silvia; Moretti, Claudio; D'Amico, Maurizio; Noussan, Patrizia; Garbo, Roberto; Hildick-Smith, David; Gaita, Fiorenzo; D'Ascenzo, Fabrizio

2018-01-01

Non-invasive ischaemia tests and biomarkers are widely adopted to rule out acute coronary syndrome in the emergency department. Their diagnostic accuracy has yet to be precisely defined. Medline, Cochrane Library CENTRAL, EMBASE and Biomed Central were systematically screened (start date 1 September 2016, end date 1 December 2016). Prospective studies (observational or randomised controlled trial) comparing functional/imaging or biochemical tests for patients presenting with chest pain to the emergency department were included. Overall, 77 studies were included, for a total of 49,541 patients (mean age 59.9 years). Fast and six-hour highly sensitive troponin T protocols did not show significant differences in their ability to detect acute coronary syndromes, as they reported a sensitivity and specificity of 0.89 (95% confidence interval 0.79-0.94) and 0.84 (0.74-0.9) vs 0.89 (0.78-0.94) and 0.83 (0.70-0.92), respectively. The addition of copeptin to troponin increased sensitivity and reduced specificity, without improving diagnostic accuracy. The diagnostic value of non-invasive tests for patients without troponin increase was tested. Coronary computed tomography showed the highest level of diagnostic accuracy (sensitivity 0.93 (0.81-0.98) and specificity 0.90 (0.93-0.94)), along with myocardial perfusion scintigraphy (sensitivity 0.85 (0.77-0.91) and specificity 0.92 (0.83-0.96)). Stress echography was inferior to coronary computed tomography but non-inferior to myocardial perfusion scintigraphy, while exercise testing showed the lower level of diagnostic accuracy. Fast and six-hour highly sensitive troponin T protocols provide an overall similar level of diagnostic accuracy to detect acute coronary syndrome. Among the non-invasive ischaemia tests for patients without troponin increase, coronary computed tomography and myocardial perfusion scintigraphy showed the highest sensitivity and specificity.

Study of the pH-sensitive mechanism of tumor-targeting liposomes.

PubMed

Fan, Yang; Chen, Cong; Huang, Yiheng; Zhang, Fang; Lin, Guimei

2017-03-01

Currently, the phosphatidylethanolamine-based, pH-sensitive, liposome drug-delivery system has been widely developed for efficient, targeted cancer therapy. However, the mechanism of pH sensitivity was unclear; it is a main obstacle in controlling the preparation of pH-sensitive liposomes (PSLs).Therefore, our research is aimed at clarifying the pH-response mechanism of the various molecules that compose liposomes. We chose the small pH-sensitive molecules oleic acid (OA), linoleic acid (LA) and cholesteryl hemisuccinate (CHEMS) and the fundamental lipids cholesterol and phosphatidylethanolamine (PE) as test molecules. The PSLs were prepared using the thin-film hydration method and characterized in detail at various pH values (pH 5.0, 6.0 and 7.4), including particle size, ζ-potential, drug encapsulation efficiency and drug loading. The surface structure was observed by transmission electron microscopy (TEM), and the electrical conductivity of the liposome dispersion was also tested. The calorimetric analysis was conducted by Nano-differential scanning calorimetry (Nano-DSC). The in vitro drug release profile showed that PSLs exhibit good pH sensitivity. At neutral pH, the particle size was approximately 150nm, and it dramatically increased at pH 5.0. The ζ-potential increased as the pH decreased. The Nano-DSC results showed that cholesterol and CHEMS can both increase the stability and phase transfer temperature of PSLs. Conductivity increased to a maximum at pH 5.0 and was rather low at pH 7.4. In conclusion, results show that the three kinds of liposomes have pH responsive release characteristics in acidic pH. The OA-PSLs have a pH sensitive point of 5. Since CHEMS has a cholesterol-like structure, it can stabilizes the phospholipid bilayer under neutral conditions as shown in the Nano-DSC data, and because it has a special steroidal rigid structure, it exhibits better pH response characteristics under acidic conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Increased sensitivity to salt stress in tocopherol-deficient Arabidopsis mutants growing in a hydroponic system

PubMed Central

Ellouzi, Hasna; Hamed, Karim Ben; Cela, Jana; Müller, Maren; Abdelly, Chedly; Munné-Bosch, Sergi

2013-01-01

Recent studies suggest that tocopherols could play physiological roles in salt tolerance but the mechanisms are still unknown. In this study, we analyzed changes in growth, mineral and oxidative status in vte1 and vte4 Arabidopsis thaliana mutants exposed to salt stress. vte1 and vte4 mutants lack α-tocopherol, but only the vte1 mutant is additionally deficient in γ-tocopherol. Results showed that a deficiency in vitamin E leads to reduced growth and increased oxidative stress in hydroponically-grown plants. This effect was observed at early stages, not only in rosettes but also in roots. The vte1 mutant was more sensitive to salt-induced oxidative stress than the wild type and the vte4 mutant. Salt sensitivity was associated with (i) high contents of Na+, (ii) reduced efficiency of PSII photochemistry (Fv/Fm ratio) and (iii) more pronounced oxidative stress as indicated by increased hydrogen peroxide and malondialdeyde levels. The vte 4 mutant, which accumulates γ- instead of α-tocopherol showed an intermediate sensitivity to salt stress between the wild type and the vte1 mutant. Contents of abscisic acid, jasmonic acid and the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid were higher in the vte1 mutant than the vte4 mutant and wild type. It is concluded that vitamin E-deficient plants show an increased sensitivity to salt stress both in rosettes and roots, therefore indicating the positive role of tocopherols in stress tolerance, not only by minimizing oxidative stress, but also controlling Na+/K+ homeostasis and hormonal balance. PMID:23299430

Interplay of Filaggrin Loss-of-Function Variants, Allergic Sensitization, and Eczema in a Longitudinal Study Covering Infancy to 18 Years of Age

PubMed Central

Ziyab, Ali H.; Karmaus, Wilfried; Yousefi, Mitra; Ewart, Susan; Schauberger, Eric; Holloway, John W.; Zhang, Hongmei; Arshad, Syed Hasan

2012-01-01

Background Immune specific genes as well as genes regulating the formation of skin barrier are major determinants for eczema manifestation. There is a debate as to whether allergic sensitization and filaggrin gene (FLG) variants lead to eczema or FLG variants and eczema increase the risk of allergic sensitization. To investigate the time-order between eczema and allergic sensitization with respect to FLG variants, data from a large prospective study covering infancy to late adolescence were analyzed. Methodology/Principal Findings Repeated measurements of eczema and allergic sensitization (documented by skin prick tests) at ages 1, 2, 4, 10, and 18 years were ascertained in the Isle of Wight birth cohort (n = 1,456). Three transition periods were analyzed: age 1-or-2 to 4, 4 to 10, and 10 to 18 years. FLG variants were genotyped in 1,150 participants. Over the three transition periods, in temporal sequence analyses of initially eczema-free participants, the combined effect of FLG variants and allergic sensitization showed a 2.92-fold (95% CI: 1.47–5.77) increased risk ratio (RR) of eczema in subsequent examinations. This overall risk was more pronounced at a younger age (transition period 1-or-2 to 4, RR = 6.47, 95% CI: 1.96–21.33). In contrast, FLG variants in combination with eczema showed a weaker, but significant, risk ratio for subsequent allergic sensitization only up to 10 years of age. Conclusions/Significance Taking the time order into account, this prospective study demonstrates for the first time, that a combination of FLG variants and allergic sensitization increased the risk of eczema in subsequent years. Also FLG variants interacted with eczema and increased the risk of subsequent allergic sensitization, which, was limited to the younger age. Hence, early restoration of defective skin barrier could prevent allergic sensitization and subsequently reduce the risk of eczema development. PMID:22403702

Mindfulness meditation and relaxation training increases time sensitivity.

PubMed

Droit-Volet, S; Fanget, M; Dambrun, M

2015-01-01

Two experiments examined the effect of mindfulness meditation and relaxation on time perception using a temporal bisection task. In Experiment 1, the participants performed a temporal task before and after exercises of mindfulness meditation or relaxation. In Experiment 2, the procedure was similar than that used in Experiment 1, except that the participants were trained to mediate or relax every day over a period of several weeks. The results showed that mindfulness meditation exercises increased sensitivity to time and lengthened perceived time. However, this temporal improvement with meditation exercises was primarily observed in the experienced meditators. Our results also showed the experienced meditators were less anxious than the novice participants, and that the sensitivity to time increased when the level of anxiety decreased. Our results were explained by the practice of mindfulness technique that had developed individuals' abilities in devoting more attention resources to temporal information processing. Copyright © 2014 Elsevier Inc. All rights reserved.

Hypothyroidism leads to increased dopamine receptor sensitivity and concentration

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

Crocker, A.D.; Overstreet, D.H.; Crocker, J.M.

1986-06-01

Rats treated with iodine-131 were confirmed to be hypothyroid by their reduced baseline core body temperatures, reduced serum thyroxine concentrations and elevated serum thyroid stimulating hormone concentrations. When hypothyroid rats were compared to euthyroid controls they were more sensitive to the effects of apomorphine (1.0 mumol/kg) on stereotypy, operant responding and body temperature and showed a smaller reduction in locomotor activity after injection of haloperidol (0.25 mumol/kg). Receptor binding studies on striatal homogenates indicated that hypothyroid rats had increased concentrations of D2 dopamine receptors but there was no change in the affinity. It is concluded that hypothyroidism increases dopamine receptormore » sensitivity by increasing receptor concentration.« less

Relationship of mechanical characteristics and microstructural features to the time-dependent edge notch sensitivity of inconel 718 sheet

NASA Technical Reports Server (NTRS)

Wilson, D. J.

1971-01-01

Time-dependent notch sensitivity of Inconel 718 sheet was observed at 900 F to 1200 F (482 - 649 C). It occurred when edge-notched specimens were loaded below the yield strength and smooth specimen tests showed that small amounts of creep consumed large rupture life fractions. The severity of the notch sensitivity was reduced by decreasing the solution temperature, increasing the time and/or temperature of aging and increasing the test temperature to 1400 F (760 C). Elimination of time-dependent notch sensitivity correlated with a change in dislocation motion mechanism from shearing to by-passing precipitate particles.

Influence of Mn concentration on magnetic topological insulator Mn xBi 2−xTe 3 thin-film Hall-effect sensor

DOE PAGES

Ni, Y.; Zhang, Z.; Nlebedim, I. C.; ...

2015-06-11

Hall-effect (HE) sensors based on high-quality Mn-doped Bi 2Te 3 topological insulator (TI) thin films have been systematically studied in this paper. Improvement of Hall sensitivity is found after doping the magnetic element Mn into Bi 2Te 3. The sensors with low Mn concentrations, Mn xBi 2-xTe 3, x = 0.01 and 0.08 show the linear behavior of Hall resistance with sensitivity about 5 Ω/T. And their Hall sensitivity shows weak dependence on temperature. For sensors with high Mn concentration (x = 0.23), the Hall resistance with respect to magnetic field shows a hysteretic behavior. Moreover, its sensitivity shows almostmore » eight times as high as that of the HE sensors with low Mn concentration. The highest sensitivity can reach 43 Ω/T at very low magnetic field. This increase of Hall sensitivity is caused by the occurrence of anomalous HE (AHE) after ferromagnetic phase transition. Our work indicates that the magnetic-element-doped TIs with AHE are good candidates for HE sensors.« less

Characterization of the insulin sensitivity of ghrelin receptor KO mice using glycemic clamps

PubMed Central

2011-01-01

Background We and others have demonstrated previously that ghrelin receptor (GhrR) knock out (KO) mice fed a high fat diet (HFD) have increased insulin sensitivity and metabolic flexibility relative to WT littermates. A striking feature of the HFD-fed GhrR KO mouse is the dramatic decrease in hepatic steatosis. To characterize further the underlying mechanisms of glucose homeostasis in GhrR KO mice, we conducted both hyperglycemic (HG) and hyperinsulinemic-euglycemic (HI-E) clamps. Additionally, we investigated tissue glucose uptake and specifically examined liver insulin sensitivity. Results Consistent with glucose tolerance-test data, in HG clamp experiments, GhrR KO mice showed a reduction in glucose-stimulated insulin release relative to WT littermates. Nevertheless, a robust 1st phase insulin secretion was still achieved, indicating that a healthy β-cell response is maintained. Additionally, GhrR KO mice demonstrated both a significantly increased glucose infusion rate and significantly reduced insulin requirement for maintenance of the HG clamp, consistent with their relative insulin sensitivity. In HI-E clamps, both LFD-fed and HFD-fed GhrR KO mice showed higher peripheral insulin sensitivity relative to WT littermates as indicated by a significant increase in insulin-stimulated glucose disposal (Rd), and decreased hepatic glucose production (HGP). HFD-fed GhrR KO mice showed a marked increase in peripheral tissue glucose uptake in a variety of tissues, including skeletal muscle, brown adipose tissue and white adipose tissue. GhrR KO mice fed a HFD also showed a modest, but significant decrease in conversion of pyruvate to glucose, as would be anticipated if these mice displayed increased liver insulin sensitivity. Additionally, the levels of UCP2 and UCP1 were reduced in the liver and BAT, respectively, in GhrR KO mice relative to WT mice. Conclusions These results indicate that improved glucose homeostasis of GhrR KO mice is characterized by robust improvements of glucose disposal in both normal and metabolically challenged states, relative to WT controls. GhrR KO mice have an intact 1st phase insulin response but require significantly less insulin for glucose disposal. Our experiments reveal that the insulin sensitivity of GhrR KO mice is due to both BW independent and dependent factors. We also provide several lines of evidence that a key feature of the GhrR KO mouse is maintenance of hepatic insulin sensitivity during metabolic challenge. PMID:21211044

[Psychosocial stressors and pain sensitivity in chronic pain disorder with somatic and psychological factors (F45.41)].

PubMed

Studer, M; Stewart, J; Egloff, N; Zürcher, E; von Känel, R; Brodbeck, J; Grosse Holtforth, M

2017-02-01

Increased pain sensitivity is characteristic for patients with chronic pain disorder with somatic and psychological factors (F45.41). Persistent stress can induce, sustain, and intensify pain sensitivity, thereby modulating pain perception. In this context, it would be favorable to investigate which psychosocial stressors are empirically linked to pain sensitivity. The aim of this study was to examine the relationship between psychosocial stressors and pain sensitivity in a naturalistic sample of patients with chronic pain disorder with somatic and psychological factors (F45.41). We assessed 166 patients with chronic pain disorder with somatic and psychological factors (F45.41) at entry into an inpatient pain clinic. Pain sensitivity was measured with a pain provocation test (Algopeg) at the middle finger and earlobe. Stressors assessed were exposure to war experiences, adverse childhood experiences, illness-related inability to work, relationship problems, and potentially life-threatening accidents. Correlation analyses and structural equation modeling were used to examine which stressors showed the strongest prediction of pain sensitivity. Patients exhibited generally heightened pain sensitivity. Both exposure to war and illness-related inability to work showed significant bivariate correlations with pain sensitivity. In addition to age, they also predicted a further increase in pain sensitivity in the structural equation model. Bearing in mind the limitations of this cross-sectional study, these findings may contribute to a better understanding of the link between psychosocial stressors and pain sensitivity.

Airway extravasation induced by increasing airway temperature in ovalbumin-sensitized rats

PubMed Central

Hsu, Chun-Chun; Tapia, Reyno J.; Lee, Lu-Yuan

2015-01-01

This study was carried out to determine whether hyperventilation of humidified warm air (HWA) induced airway extravasation in ovalbumin (Ova)-sensitized rats. Our results showed: 1) After isocapnic hyperventilation with HWA for 2 min, tracheal temperature (Ttr) was increased to 40.3°C, and the Evans blue contents in major airways and lung tissue were elevated to 651% and 707%, respectively, of that after hyperventilation with humidified room air in Ova-sensitized rats; this striking effect of HWA was absent in control rats. 2) The HWA-induced increase in Evans blue content in sensitized rats was completely prevented by a pretreatment with either L-732138, a selective antagonist of neurokinin type 1 (NK-1) receptor, or formoterol, a selective agonist of β2 adrenoceptor. This study demonstrated that an increase in airway temperature induced protein extravasation in the major airways and lung tissue of sensitized rats, and an activation of the NK-1 receptor by tachykinins released from bronchopulmonary C-fiber nerve endings was primarily responsible. PMID:25864799

Sensitizers in EUV chemically amplified resist: mechanism of sensitivity improvement

NASA Astrophysics Data System (ADS)

Vesters, Yannick; Jiang, Jing; Yamamoto, Hiroki; De Simone, Danilo; Kozawa, Takahiro; De Gendt, Stefan; Vandenberghe, Geert

2018-03-01

EUV lithography utilizes photons with 91.6 eV energy to ionize resists, generate secondary electrons, and enable electron driven reactions that produce acid in chemically amplified photoresist. Efficiently using the available photons is of key importance. Unlike DUV lithography, where photons are selectively utilized by photoactive compounds, photons at 13.5nm wavelength ionize almost all materials. Nevertheless, specific elements have a significantly higher atomic photon-absorption cross section at 91.6 eV. To increase photon absorption, sensitizer molecules, containing highly absorbing elements, can be added to photoresist formulations. These sensitizers have gained growing attention in recent years, showing significant sensitivity improvement. But there are few experimental evidences that the sensitivity improvement is due to the higher absorption only, as adding metals salts into the resist formulation can induce other mechanisms, like modification of the dissolution rate, potentially affecting patterning performance. In this work, we used different sensitizers in chemically amplified resist. We measured experimentally the absorption of EUV light, the acid yield, the dissolution rate and the patterning performance of the resists. Surprisingly, the absorption of EUV resist was decreased with addition of metal salt sensitizers. Nevertheless, the resist with sensitizer showed a higher acid yield. Sensitizer helps achieving higher PAG conversion to acid, notably due to an increase of the secondary electron generation. Patterning data confirm a significant sensitivity improvement, but at the cost of roughness degradation at high sensitizer loading. This can be explained by the chemical distribution of the sensitizer in the resist combined with a modification of the dissolution contrast, as observed by Dissolution Rate Monitor.

Effects of slow breathing rate on heart rate variability and arterial baroreflex sensitivity in essential hypertension.

PubMed

Li, Changjun; Chang, Qinghua; Zhang, Jia; Chai, Wenshu

2018-05-01

This study is to investigate the effects of slow breathing on heart rate variability (HRV) and arterial baroreflex sensitivity in essential hypertension.We studied 60 patients with essential hypertension and 60 healthy controls. All subjects underwent controlled breathing at 8 and 16 breaths per minute. Electrocardiogram, respiratory, and blood pressure signals were recorded simultaneously. We studied effects of slow breathing on heart rate, blood pressure and respiratory peak, high-frequency (HF) power, low-frequency (LF) power, and LF/HF ratio of HRV with traditional and corrected spectral analysis. Besides, we tested whether slow breathing was capable of modifying baroreflex sensitivity in hypertensive subjects.Slow breathing, compared with 16 breaths per minute, decreased the heart rate and blood pressure (all P < .05), and shifted respiratory peak toward left (P < .05). Compared to 16 breaths/minute, traditional spectral analysis showed increased LF power and LF/HF ratio, decreased HF power of HRV at 8 breaths per minute (P < .05). As breathing rate decreased, corrected spectral analysis showed increased HF power, decreased LF power, LF/HF ratio of HRV (P < .05). Compared to controls, resting baroreflex sensitivity decreased in hypertensive subjects. Slow breathing increased baroreflex sensitivity in hypertensive subjects (from 59.48 ± 6.39 to 78.93 ± 5.04 ms/mm Hg, P < .05) and controls (from 88.49 ± 6.01 to 112.91 ± 7.29 ms/mm Hg, P < .05).Slow breathing can increase HF power and decrease LF power and LF/HF ratio in essential hypertension. Besides, slow breathing increased baroreflex sensitivity in hypertensive subjects. These demonstrate slow breathing is indeed capable of shifting sympatho-vagal balance toward vagal activities and increasing baroreflex sensitivity, suggesting a safe, therapeutic approach for essential hypertension.

Specific down-regulation of XIAP with RNA interference enhances the sensitivity of canine tumor cell-lines to TRAIL and doxorubicin

PubMed Central

Spee, Bart; Jonkers, Martijn DB; Arends, Brigitte; Rutteman, Gerard R; Rothuizen, Jan; Penning, Louis C

2006-01-01

Background Apoptosis resistance occurs in various tumors. The anti-apoptotic XIAP protein is responsible for inhibiting apoptosis by reducing caspase-3 activation. Our aim is to evaluate whether RNA inhibition against XIAP increases the sensitivity of canine cell-lines for chemotherapeutics such as TRAIL and doxorubicin. We used small interfering RNA's (siRNA) directed against XIAP in three cell-lines derived from bile-duct epithelia (BDE), mammary carcinoma (P114), and osteosarcoma (D17). These cell-lines represent frequently occurring canine cancers and are highly comparable to their human counterparts. XIAP down-regulation was measured by means of quantitative PCR (Q-PCR) and Western blotting. The XIAP depleted cells were treated with a serial dilution of TRAIL or doxorubicin and compared to mock- and nonsense-treated controls. Viability was measured with a MTT assay. Results All XIAP siRNA treated cell-lines showed a mRNA down-regulation over 80 percent. Western blot analysis confirmed mRNA measurements. No compensatory effect of IAP family members was seen in XIAP depleted cells. The sensitivity of XIAP depleted cells for TRAIL was highest in BDE cells with an increase in the ED50 of 14-fold, compared to mock- and nonsense-treated controls. The sensitivity of P114 and D17 cell-lines increased six- and five-fold, respectively. Doxorubicin treatment in XIAP depleted cells increased sensitivity in BDE cells more than eight-fold, whereas P114 and D17 cell-lines showed an increase in sensitivity of three- and five-fold, respectively. Conclusion XIAP directed siRNA's have a strong sensitizing effect on TRAIL-reduced cell-viability and a smaller but significant effect with the DNA damaging drug doxorubicin. The increase in efficacy of chemotherapeutics with XIAP depletion provides the rationale for the use of XIAP siRNA's in insensitive canine tumors. PMID:16953886

Telomerase antagonist imetelstat increases radiation sensitivity in esophageal squamous cell carcinoma

PubMed Central

Wu, Xuping; Zhang, Jing; Yang, Sijun; Kuang, Zhihui; Tan, Guolei; Yang, Gang; Wei, Qichun; Guo, Zhigang

2017-01-01

The morbidity and mortality of esophageal cancer is one of the highest around the world and the principal therapeutic method is radiation. Thus, searching for sensitizers with lower toxicity and higher efficiency to improve the efficacy of radiation therapy is critical essential. Our research group has previously reported that imetelstat, the thio-phosphoramidate oligonucleotide inhibitor of telomerase, can decrease cell proliferation and colony formation ability as well as increase DNA breaks induced by radiation in esophageal cancer cells. Further study in this project showed that imetelstat significantly sensitized esophageal cancer cells to radiation in vitro. Later study showed that imetelstat leads to increased cell apoptosis. We also measured the expression level of several DNA repair and apoptosis signaling proteins. pS345 CHK1, γ-H2AX, p53 and caspase3 expression were up-regulated in imetelstat treated cells, identifying these factors as molecular markers. Mouse in vivo model using imetelstat at clinically achievable concentrations and fractionated irradiation scheme yielded results demonstrating radiosensitization effect. Finally, TUNEL assay, caspase 3 and Ki67 staining in tumor tissue proved that imetelstat sensitized esophageal cancer to radiation in vivo through promoting cell apoptosis and inhibiting cell proliferation. Our study supported imetelstat increase radiation sensitivity of esophageal squamous cell carcinoma through inducing cell apoptosis and the specific inhibitor of telomerase might serve as a potential novel therapeutic tool for esophageal squamous cell carcinoma therapy. PMID:28099140

Telomerase antagonist imetelstat increases radiation sensitivity in esophageal squamous cell carcinoma.

PubMed

Wu, Xuping; Zhang, Jing; Yang, Sijun; Kuang, Zhihui; Tan, Guolei; Yang, Gang; Wei, Qichun; Guo, Zhigang

2017-02-21

The morbidity and mortality of esophageal cancer is one of the highest around the world and the principal therapeutic method is radiation. Thus, searching for sensitizers with lower toxicity and higher efficiency to improve the efficacy of radiation therapy is critical essential. Our research group has previously reported that imetelstat, the thio-phosphoramidate oligonucleotide inhibitor of telomerase, can decrease cell proliferation and colony formation ability as well as increase DNA breaks induced by radiation in esophageal cancer cells. Further study in this project showed that imetelstat significantly sensitized esophageal cancer cells to radiation in vitro. Later study showed that imetelstat leads to increased cell apoptosis. We also measured the expression level of several DNA repair and apoptosis signaling proteins. pS345 CHK1, γ-H2AX, p53 and caspase3 expression were up-regulated in imetelstat treated cells, identifying these factors as molecular markers. Mouse in vivo model using imetelstat at clinically achievable concentrations and fractionated irradiation scheme yielded results demonstrating radiosensitization effect. Finally, TUNEL assay, caspase 3 and Ki67 staining in tumor tissue proved that imetelstat sensitized esophageal cancer to radiation in vivo through promoting cell apoptosis and inhibiting cell proliferation. Our study supported imetelstat increase radiation sensitivity of esophageal squamous cell carcinoma through inducing cell apoptosis and the specific inhibitor of telomerase might serve as a potential novel therapeutic tool for esophageal squamous cell carcinoma therapy.

The Effects of Climate Sensitivity and Carbon Cycle Interactions on Mitigation Policy Stringency

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

Calvin, Katherine V.; Bond-Lamberty, Benjamin; Edmonds, James A.

2015-07-01

Climate sensitivity and climate-carbon cycle feedbacks interact to determine how global carbon and energy cycles will change in the future. While the science of these connections is well documented, their economic implications are not well understood. Here we examine the effect of climate change on the carbon cycle, the uncertainty in climate outcomes inherent in any given policy target, and the economic implications. We examine three policy scenarios—a no policy “Reference” (REF) scenario, and two policies that limit total radiative forcing—with four climate sensitivities using a coupled integrated assessment model. Like previous work, we find that, within a given scenario,more » there is a wide range of temperature change and sea level rise depending on the realized climate sensitivity. We expand on this previous work to show that temperature-related feedbacks on the carbon cycle result in more mitigation required as climate sensitivity increases. Thus, achieving a particular radiative forcing target becomes increasingly expensive as climate sensitivity increases.« less

Influence of polyunsaturated fatty acid supplementation and membrane fluidity on ozone and nitrogen dioxide sensitivity of rat alveolar macrophages

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

Rietjens, I.M.; van Tilburg, C.A.; Coenen, T.M.

1987-01-01

The phospholipid polyunsaturated fatty acid (PUFA) content and the membrane fluidity of rat alveolar macrophages were modified dose-dependently and in different ways. This was done to study the importance of both membrane characteristics for the cellular sensitivity toward ozone and nitrogen dioxide. Cells preincubated with arachidonic acid (20:4) complexed to bovine serum albumin (BSA) demonstrated an increased in vitro sensitivity versus ozone and nitrogen dioxide. The phenomenon was only observed at the highest 20:4 concentrations tested, whereas the membrane fluidity of the 20:4-treated cells already showed a maximum increase at lower preincubation concentrations. Hence it could be concluded that themore » increased ozone and nitrogen dioxide sensitivity of PUFA-enriched cells is not caused by their increased membrane fluidity, resulting in an increased accessibility of sensitive cellular fatty acid moieties or amino acid residues. This conclusion receives further support from other observations. These results strongly support the involvement of lipid oxidation in the mechanism(s) of toxic action of both ozone and nitrogen dioxide in an intact cell system.« less

[Validity of expired carbon monoxide and urine cotinine using dipstick method to assess smoking status].

PubMed

Park, Su San; Lee, Ju Yul; Cho, Sung-Il

2007-07-01

We investigated the validity of the dipstick method (Mossman Associates Inc. USA) and the expired CO method to distinguish between smokers and nonsmokers. We also elucidated the related factors of the two methods. This study included 244 smokers and 50 ex-smokers, recruited from smoking cessation clinics at 4 local public health centers, who had quit for over 4 weeks. We calculated the sensitivity, specificity and Kappa coefficient of each method for validity. We obtained ROC curve, predictive value and agreement to determine the cutoff of expired air CO method. Finally, we elucidated the related factors and compared their effect powers using the standardized regression coefficient. The dipstick method showed a sensitivity of 92.6%, specificity of 96.0% and Kappa coefficient of 0.79. The best cutoff value to distinguish smokers was 5-6 ppm. At 5 ppm, the expired CO method showed a sensitivity of 94.3%, specificity of 82.0% and Kappa coefficient of 0.73. And at 6 ppm, sensitivity, specificity and Kappa coefficient were 88.5%, 86.0% and 0.64, respectively. Therefore, the dipstick method had higher sensitivity and specificity than the expired CO method. The dipstick and expired CO methods were significantly increased with increasing smoking amount. With longer time since the last smoking, expired CO showed a rapid decrease after 4 hours, whereas the dipstick method showed relatively stable levels for more than 4 hours. The dipstick and expired CO methods were both good indicators for assessing smoking status. However, the former showed higher sensitivity and specificity and stable levels over longer hours after smoking, compared to the expired CO method.

Impact sensitivity of materials in contact with liquid and gaseous oxygen at high pressure

NASA Technical Reports Server (NTRS)

Schwinghamer, R. J.

1972-01-01

As a result of the Apollo 13 incident, increased emphasis is being placed on materials compatibility in a high pressure GOX environment. It is known that in addition to impact sensitivity of materials, approximately adiabatic compression conditions can contrive to induce materials reactivity. Test runs at high pressure using the ABMA tester indicate the following: (1) The materials used in the tests showed an inverse relationship between thickness and impact sensitivity. (2) Several materials tested exhibited greater impact sensitivity in GOX than in LOX. (3) The impact sensitivity of the materials tested in GOX, at the pressures tested, showed enhanced impact sensitivity with higher pressure. (4) The rank ordering of the materials tested in LOX up to 1000 psia is the same as the rank ordering resulting from tests in LOX at 14.7 psia.

The role of interleukin-8 (IL-8) and IL-8 receptors in platinum response in high grade serous ovarian carcinoma

PubMed Central

Stronach, Euan A.; Cunnea, Paula; Turner, Christina; Guney, Tankut; Aiyappa, Radhika; Jeyapalan, Senthuran; de Sousa, Camila H.; Browne, Alacoque; Magdy, Nesreen; Studd, James B.; Sriraksa, Ruethairat; Gabra, Hani; El-Bahrawy, Mona

2015-01-01

Platinum based drugs are the cornerstone of chemotherapy for ovarian cancer, however the development of chemoresistance hinders its success. IL-8 is involved in regulating several pro-survival pathways in cancer. We studied the expression of IL-8 and IL-8 receptors in platinum sensitive and resistant cell lines. Using qRT-PCR and immunohistochemistry, both platinum sensitive (PEA1, PEO14) and resistant (PEA2, PEO23) show increased expression of IL-8 and IL-8 receptors. IL-8RA shows nuclear and cytoplasmic expression, whilst IL-8RB is present solely in the cytoplasm. Knockdown of IL-8 increased sensitivity to cisplatin in platinum sensitive and reversed platinum resistance in resistant cell lines, decreased the expression of anti-apoptotic Bcl-2 and decreased inhibitory phosphorylation of pro-apoptotic Bad. IL-8 receptor antagonist treatment also enhanced platinum sensitivity. Nuclear localisation of IL-8RA was only detected in platinum resistant tumours. Inhibition of IL-8 signalling can enhance response in platinum sensitive and resistant disease. Nuclear IL-8RA may have potential as a biomarker of resistant disease. PMID:26267317

The role of interleukin-8 (IL-8) and IL-8 receptors in platinum response in high grade serous ovarian carcinoma.

PubMed

Stronach, Euan A; Cunnea, Paula; Turner, Christina; Guney, Tankut; Aiyappa, Radhika; Jeyapalan, Senthuran; de Sousa, Camila H; Browne, Alacoque; Magdy, Nesreen; Studd, James B; Sriraksa, Ruethairat; Gabra, Hani; El-Bahrawy, Mona

2015-10-13

Platinum based drugs are the cornerstone of chemotherapy for ovarian cancer, however the development of chemoresistance hinders its success. IL-8 is involved in regulating several pro-survival pathways in cancer. We studied the expression of IL-8 and IL-8 receptors in platinum sensitive and resistant cell lines. Using qRT-PCR and immunohistochemistry, both platinum sensitive (PEA1, PEO14) and resistant (PEA2, PEO23) show increased expression of IL-8 and IL-8 receptors. IL-8RA shows nuclear and cytoplasmic expression, whilst IL-8RB is present solely in the cytoplasm. Knockdown of IL-8 increased sensitivity to cisplatin in platinum sensitive and reversed platinum resistance in resistant cell lines, decreased the expression of anti-apoptotic Bcl-2 and decreased inhibitory phosphorylation of pro-apoptotic Bad. IL-8 receptor antagonist treatment also enhanced platinum sensitivity. Nuclear localisation of IL-8RA was only detected in platinum resistant tumours. Inhibition of IL-8 signalling can enhance response in platinum sensitive and resistant disease. Nuclear IL-8RA may have potential as a biomarker of resistant disease.

Anti-adhesive effect of poloxamer-based thermo-sensitive sol-gel in rabbit laminectomy model.

PubMed

Shin, Sung Joon; Lee, Jae Hyup; So, Jungwon; Min, Kyungdan

2016-11-01

Poloxamer-based thermo-sensitive sol-gel has been developed to reduce the incidence of postoperative scar formation at the laminectomy site. The purpose of this study was to evaluate the anti-adhesive effect of poloxamer based thermo-sensitive sol-gel compared to hyaluronate based solution after laminectomy, using a rabbit model. A thermo-sensitive anti-adhesive with a property of sol-gel transition was manufactured by a physical mixture of Poloxamer188/407, Chitosan and Gelatin. The viscosity in different temperatures was assessed. 72 adult New Zealand rabbits underwent lumbar laminectomy and were randomly divided into experimental (treated with the newly developed agent), positive (treated with hyaluronate based solution), and negative control groups. Each group was subdivided into 1 and 4-week subgroups. Gross and histological evaluations were performed to assess the extent of epidural adhesion. The experimental group showed significantly higher viscosity compared to the positive control group and showed a significant increase of viscosity as the temperature increased. Gross evaluation showed no statistically significant differences between the 1- and 4-week subgroups. However, histologic evaluation showed significant differences both in 1- and 4-week subgroups. Although the 4-week histologic results of the experimental and the positive control subgroups showed no significant difference, both subgroups revealed higher value compared to the negative control subgroup with regard to the ratio of adhesion less than 50 %. The new poloxamer based thermo-sensitive agent showed superior efficacy over the hyaluronate based agent at 1 week postoperatively. At 4 weeks postoperatively, there were no statistically significant differences between the two agents, although both showed efficacy over the sham group.

Rotation sensitivity analysis of a two-dimensional array of coupled resonators

NASA Astrophysics Data System (ADS)

Zamani Aghaie, Kiarash; Vigneron, Pierre-Baptiste; Digonnet, Michel J. F.

2015-03-01

In this paper, we study the rotation sensitivity of a gyroscope made of a two-dimensional array of coupled resonators consisting of N columns of one-dimensional coupled resonant optical waveguides (CROWs) connected by two bus waveguides, each CROW consisting of M identical ring resonators. We show that the maximum rotation sensitivity of this structure is a strong function of the parity of the number of rows M. For an odd number of rows, and when the number of columns is small, the maximum sensitivity is high, and it is slightly lower than the maximum sensitivity of a single-ring resonator with two input/output waveguides (the case M = N = 1), which is a resonant waveguide optical gyroscope (RWOG). For an even M and small N, the maximum sensitivity is much lower than that of the RWOG. Increasing the number columns N increases the sensitivity of an even-row 2D CROW sublinearly, as N0.39, up to 30 columns. In comparison, the maximum sensitivity of an RWOG of equal area increases faster, as √N. The sensitivity of the 2D CROW therefore always lags behind that of the RWOG. For a 2×2 CROW, if the spacing between the columns L is increased sufficiently the maximum sensitivity increases linearly with L due to the presence of a composite Mach- Zehnder interferometer in the structure. However, for equal footprints this sensitivity is also not larger than that of a single-ring resonator. Regardless of the number of rows and columns and the spacing, for the same footprint and propagation loss, a 2D CROW gyroscope is not more sensitive than an RWOG.

Enhanced sensitivity to glucocorticoids in cytarabine-resistant AML.

PubMed

Malani, D; Murumägi, A; Yadav, B; Kontro, M; Eldfors, S; Kumar, A; Karjalainen, R; Majumder, M M; Ojamies, P; Pemovska, T; Wennerberg, K; Heckman, C; Porkka, K; Wolf, M; Aittokallio, T; Kallioniemi, O

2017-05-01

We sought to identify drugs that could counteract cytarabine resistance in acute myeloid leukemia (AML) by generating eight resistant variants from MOLM-13 and SHI-1 AML cell lines by long-term drug treatment. These cells were compared with 66 ex vivo chemorefractory samples from cytarabine-treated AML patients. The models and patient cells were subjected to genomic and transcriptomic profiling and high-throughput testing with 250 emerging and clinical oncology compounds. Genomic profiling uncovered deletion of the deoxycytidine kinase (DCK) gene in both MOLM-13- and SHI-1-derived cytarabine-resistant variants and in an AML patient sample. Cytarabine-resistant SHI-1 variants and a subset of chemorefractory AML patient samples showed increased sensitivity to glucocorticoids that are often used in treatment of lymphoid leukemia but not AML. Paired samples taken from AML patients before treatment and at relapse also showed acquisition of glucocorticoid sensitivity. Enhanced glucocorticoid sensitivity was only seen in AML patient samples that were negative for the FLT3 mutation (P=0.0006). Our study shows that development of cytarabine resistance is associated with increased sensitivity to glucocorticoids in a subset of AML, suggesting a new therapeutic strategy that should be explored in a clinical trial of chemorefractory AML patients carrying wild-type FLT3.

Enhanced sensitivity to glucocorticoids in cytarabine-resistant AML

PubMed Central

Malani, D; Murumägi, A; Yadav, B; Kontro, M; Eldfors, S; Kumar, A; Karjalainen, R; Majumder, M M; Ojamies, P; Pemovska, T; Wennerberg, K; Heckman, C; Porkka, K; Wolf, M; Aittokallio, T; Kallioniemi, O

2017-01-01

We sought to identify drugs that could counteract cytarabine resistance in acute myeloid leukemia (AML) by generating eight resistant variants from MOLM-13 and SHI-1 AML cell lines by long-term drug treatment. These cells were compared with 66 ex vivo chemorefractory samples from cytarabine-treated AML patients. The models and patient cells were subjected to genomic and transcriptomic profiling and high-throughput testing with 250 emerging and clinical oncology compounds. Genomic profiling uncovered deletion of the deoxycytidine kinase (DCK) gene in both MOLM-13- and SHI-1-derived cytarabine-resistant variants and in an AML patient sample. Cytarabine-resistant SHI-1 variants and a subset of chemorefractory AML patient samples showed increased sensitivity to glucocorticoids that are often used in treatment of lymphoid leukemia but not AML. Paired samples taken from AML patients before treatment and at relapse also showed acquisition of glucocorticoid sensitivity. Enhanced glucocorticoid sensitivity was only seen in AML patient samples that were negative for the FLT3 mutation (P=0.0006). Our study shows that development of cytarabine resistance is associated with increased sensitivity to glucocorticoids in a subset of AML, suggesting a new therapeutic strategy that should be explored in a clinical trial of chemorefractory AML patients carrying wild-type FLT3. PMID:27833094

Altered sensitization patterns to sweet food stimuli in patients recovered from anorexia and bulimia nervosa.

PubMed

Wagner, Angela; Simmons, Alan N; Oberndorfer, Tyson A; Frank, Guido K W; McCurdy-McKinnon, Danyale; Fudge, Julie L; Yang, Tony T; Paulus, Martin P; Kaye, Walter H

2015-12-30

Recent studies show that higher-order appetitive neural circuitry may contribute to restricted eating in anorexia nervosa (AN) and overeating in bulimia nervosa (BN). The purpose of this study was to determine whether sensitization effects might underlie pathologic eating behavior when a taste stimulus is administered repeatedly. Recovered AN (RAN, n=14) and BN (RBN, n=15) subjects were studied in order to avoid the confounding effects of altered nutritional state. Functional magnetic resonance imaging (fMRI) measured higher-order brain response to repeated tastes of sucrose (caloric) and sucralose (non-caloric). To test sensitization, the neuronal response to the first and second administration was compared. RAN patients demonstrated a decreased sensitization to sucrose in contrast to RBN patients who displayed the opposite pattern, increased sensitization to sucrose. However, the latter was not as pronounced as in healthy control women (n=13). While both eating disorder subgroups showed increased sensitization to sucralose, the healthy controls revealed decreased sensitization. These findings could reflect on a neuronal level the high caloric intake of RBN during binges and the low energy intake for RAN. RAN seem to distinguish between high energy and low energy sweet stimuli while RBN do not. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Fluid shear stress enhances the cell volume decrease of osteoblast cells by increasing the expression of the ClC-3 chloride channel

PubMed Central

LIU, LI; CAI, SIYI; QIU, GUIXING; LIN, JIN

2016-01-01

ClC-3 is a volume-sensitive chloride channel that is responsible for cell volume adjustment and regulatory cell volume decrease (RVD). In order to evaluate the effects of fluid shear stress (FSS) stimulation on the osteoblast ClC-3 chloride channel, MC3T3-E1 cells were stimulated by FSS in the experimental group. Fluorescence quantitative polymerase chain reaction was used to detect changes in ClC-3 mRNA expression, the chloride ion fluorescent probe N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (MQAE) was used to detect the chloride channel activity, and whole-cell patch clamping was used to monitor the changes in the volume-sensitive chloride current activated by a hypotonic environment following mechanical stimulation. The results show that the expression of the osteoblast chloride channel ClC-3 was significantly higher in the FSS group compared with the control group. MQAE fluorescence intensity was significantly reduced in the FSS group compared to the control group, suggesting that mechanical stimulation increased chloride channel activity and increased the efflux of intracellular chloride ions. Image analysis of osteoblast volume changes showed that osteoblast RVD was enhanced by mechanical stimulation. Whole-cell patch clamping showed that the osteoblast volume-sensitive chloride current was larger in the stimulated group compared to the control group, suggesting that elevated ClC-3 chloride channel expression results in an increased volume-sensitive chloride current. In conclusion, FSS stimulation enhances the RVD of osteoblast cell by increasing the expression of the ClC-3 and enhancing the chloride channel activity. PMID:27073622

A novel photonic crystal fiber Mach-Zehnder interferometer for enhancing refractive index measurement sensitivity

NASA Astrophysics Data System (ADS)

Zhao, Yong; Xia, Feng; Hu, Hai-feng; Chen, Mao-qing

2017-11-01

A novel refractive index (RI) sensor based on photonic crystal fiber Mach-Zehnder interferometer (PCF-MZI) was proposed. It was realized by cascading a section of PCF with half-taper collapse regions (HTCRs) between two single mode fibers (SMFs). The relationship between RI sensitivity and interference length of the PCF-MZI was firstly investigated. Both simulation and experimental results showed that RI sensitivity increased with the increase of interference length. Afterwards, influence of HTCR parameters on RI sensitivity was experimentally investigated to further improve the sensitivity. With intensification of arc discharge intensity in HTCR fabrication process, HTCR with larger maximum taper diameter and longer collapsed region length was obtained, which enhanced evanescent field of the PCF-MZI and then generated higher RI sensitivity. Consequently, a high RI sensitivity of 181.96 nm/refractive index unit (RIU) was achieved in the RI range of 1.3333-1.3574. Increasing arc discharge intensity in HTCR fabrication process has the capacity to improve RI sensitivity of PCF-MZI and meanwhile provides higher mechanical strength and longer sensor life compared to the traditional method of tapering the fiber, which improves the RI sensitivity at the cost of reducing mechanical strength of the sensor. This PCF-MZI was characterized by high RI sensitivity, ease of fabrication, high mechanical strength, and robustness.

Individual modulation of pain sensitivity under stress.

PubMed

Reinhardt, Tatyana; Kleindienst, Nikolaus; Treede, Rolf-Detlef; Bohus, Martin; Schmahl, Christian

2013-05-01

Stress has a strong influence on pain sensitivity. However, the direction of this influence is unclear. Recent studies reported both decreased and increased pain sensitivities under stress, and one hypothesis is that interindividual differences account for these differences. The aim of our study was to investigate the effect of stress on individual pain sensitivity in a relatively large female sample. Eighty female participants were included. Pain thresholds and temporal summation of pain were tested before and after stress, which was induced by the Mannheim Multicomponent Stress Test. In an independent sample of 20 women, correlation coefficients between 0.45 and 0.89 indicated relatively high test-retest reliability for pain measurements. On average, there were significant differences between pain thresholds under non-stress and stress conditions, indicating an increased sensitivity to pain under stress. No significant differences between non-stress and stress conditions were found for temporal summation of pain. On an individual basis, both decreased and increased pain sensitivities under stress conditions based on Jacobson's criteria for reliable change were observed. Furthermore, we found significant negative associations between pain sensitivity under non-stress conditions and individual change of pain sensitivity under stress. Participants with relatively high pain sensitivity under non-stress conditions became less sensitive under stress and vice versa. These findings support the view that pain sensitivity under stress shows large interindividual variability, and point to a possible dichotomy of altered pain sensitivity under stress. Wiley Periodicals, Inc.

Germline missense pathogenic variants in the BRCA1 BRCT domain, p.Gly1706Glu and p.Ala1708Glu, increase cellular sensitivity to PARP inhibitor olaparib by a dominant negative effect

PubMed Central

Vaclová, Tereza; Woods, Nicholas T.; Megías, Diego; Gomez-Lopez, Sergio; Setién, Fernando; García Bueno, José María; Macías, José Antonio; Barroso, Alicia; Urioste, Miguel; Esteller, Manel; Monteiro, Alvaro N.A.; Benítez, Javier; Osorio, Ana

2016-01-01

Abstract BRCA1-deficient cells show defects in DNA repair and rely on other members of the DNA repair machinery, which makes them sensitive to PARP inhibitors (PARPi). Although carrying a germline pathogenic variant in BRCA1/2 is the best determinant of response to PARPi, a significant percentage of the patients do not show sensitivity and/or display increased toxicity to the agent. Considering previously suggested mutation-specific BRCA1 haploinsufficiency, we aimed to investigate whether there are any differences in cellular response to PARPi olaparib depending on the BRCA1 mutation type. Lymphoblastoid cell lines derived from carriers of missense pathogenic variants in the BRCA1 BRCT domain (c.5117G > A, p.Gly1706Glu and c.5123C > A, p.Ala1708Glu) showed higher sensitivity to olaparib than cells with truncating variants or wild types (WT). Response to olaparib depended on a basal PARP enzymatic activity, but did not correlate with PARP1 expression. Interestingly, cellular sensitivity to the agent was associated with the level of BRCA1 recruitment into γH2AX foci, being the lowest in cells with missense variants. Since these variants lead to partially stable protein mutants, we propose a model in which the mutant protein acts in a dominant negative manner on the WT BRCA1, impairing the recruitment of BRCA1 into DNA damage sites and, consequently, increasing cellular sensitivity to PARPi. Taken together, our results indicate that carriers of different BRCA1 mutations could benefit from olaparib in a distinct way and show different toxicities to the agent, which could be especially relevant for a potential future use of PARPi as prophylactic agents in BRCA1 mutation carriers. PMID:27742776

Reduction in insulin sensitivity and inadequate β-cell capacity to counteract the increase in insulin resistance in children with idiopathic growth hormone deficiency during 12 months of growth hormone treatment.

PubMed

Ciresi, A; Amato, M C; Giordano, C

2015-03-01

To evaluate the performance of various indexes of insulin sensitivity and secretion and to identify the most useful indicator of deterioration of glucose metabolism in a cohort of children with growth hormone (GH) deficiency (GHD) during GH treatment. In 73 GHD children (55 M, 18 F; mean age 10.5 years) at baseline and after 12 months of treatment, we evaluated a number of surrogate indexes of insulin secretion and sensitivity. In a subgroup of 11 children we also performed an euglycemic hyperinsulinemic clamp. After 12 months, a significant increase in fasting glucose (p < 0.001) and HbA1c levels (p < 0.001) was documented, despite all children remained with a normal glucose tolerance. With regard the insulin secretion, Homa-β did not show any significant change (p = 0.073), while oral disposition index (DIo) showed a significant decrease (p = 0.031). With regard the insulin sensitivity, Homa-IR significantly increased (p < 0.001) with a concomitant decrease in QUICKI (p < 0.001). ISI Matsuda showed a decrease, although not statistically significant (p = 0.069). In the subgroup of 11 children, the M value derived from clamp showed a significant decrease (p = 0.011) and a significant positive correlation was found between M value and ISI Matsuda both at baseline (ρ 0.950; p = 0.001) and after 12 months (ρ 0.980; p = 0.001) but not with Homa-IR and QUICKI. 12 months of GH treatment lead to a decrease in insulin sensitivity and impairment in insulin secretion relative to insulin sensitivity even without evident changes in glucose tolerance. DIo has proven to be the most useful indicator of deterioration of glucose metabolism even in cases in which the overt glucose abnormalities have not yet appeared.

A DRD4 Gene by Maternal Sensitivity Interaction Predicts Risk for Overweight or Obesity in Two Independent Cohorts of Preschool Children

ERIC Educational Resources Information Center

Levitan, Robert D.; Jansen, Pauline; Wendland, Barbara; Tiemeier, Henning; Jaddoe, Vincent W.; Silveira, Patricia P.; Kennedy, James L.; Atkinson, Leslie; Fleming, Alison; Sokolowski, Marla; Gaudreau, Helene; Steiner, Meir; Dubé, Laurette; Hamilton, Jill; Moss, Ellen; Wazana, Ashley; Meaney, Michael

2017-01-01

Background: Recent evidence suggests that early exposure to low maternal sensitivity is a risk factor for obesity in children and adolescents. A separate line of study shows that the seven-repeat (7R) allele of the dopamine-4 receptor gene (DRD4) increases susceptibility to environmental factors including maternal sensitivity. The current study…

High Fat Diet Augments Amphetamine Sensitization in Mice: Role of Feeding Pattern, Obesity, and Dopamine Terminal Changes

PubMed Central

Fordahl, Steve C.; Locke, Jason L.; Jones, Sara R.

2016-01-01

High fat (HF) diet-induced obesity has been shown to augment behavioral responses to psychostimulants that target the dopamine system. The purpose of this study was to characterize dopamine terminal changes induced by a HF diet that correspond with enhanced locomotor sensitization to amphetamine. C57BL/6J mice had limited (2hr 3d/week) or extended (24h 7d/week) access to a HF diet or standard chow for six weeks. Mice were then repeatedly exposed to amphetamine (AMPH), and their locomotor responses to an amphetamine challenge were measured. Fast scan cyclic voltammetry was used to identify changes in dopamine terminal function after AMPH exposure. Exposure to a HF diet reduced dopamine uptake and increased locomotor responses to acute, high-dose AMPH administration compared to chow fed mice. Microdialysis showed elevated extracellular dopamine in the nucleus accumbens (NAc) coincided with enhanced locomotion after acute AMPH in HF-fed mice. All mice exhibited locomotor sensitization to amphetamine, but both extended and limited access to a HF diet augmented this response. Neither HF-fed group showed the robust amphetamine sensitization-induced increases in dopamine release, reuptake, and amphetamine potency observed in chow fed animals. However, the potency of amphetamine as an uptake inhibitor was significantly elevated after sensitization in mice with extended (but not limited) access to HF. Conversely, after amphetamine sensitization, mice with limited (but not extended) access to HF displayed reduced autoreceptor sensitivity to the D2/D3 agonist quinpirole. Additionally, we observed reduced membrane dopamine transporter (DAT) levels after HF, and a shift in DAT localization to the cytosol was detected with limited access to HF. This study showed that different patterns of HF exposure produced distinct dopamine terminal adaptations to repeated AMPH, which differed from chow fed mice, and enhanced sensitization to AMPH. Locomotor sensitization in chow fed mice coincided with elevated DAT function and increased AMPH potency; however, the enhanced behavioral response to AMPH after HF exposure was unique in that it coincided with reduced DAT function and diet pattern-specific adaptations. PMID:27267686

Developmental programming: insulin sensitizer treatment improves reproductive function in prenatal testosterone-treated female sheep.

PubMed

Veiga-Lopez, Almudena; Lee, James S; Padmanabhan, Vasantha

2010-08-01

Prenatal testosterone (T) excess causes reproductive and metabolic disruptions including insulin resistance, attributes of women with polycystic ovary syndrome. This study tested the hypothesis that insulin resistance contributes toward severity of reproductive disruptions in prenatally T-treated females. Pregnant sheep were injected im with 100 mg of T-propionate semiweekly from d 30-90 of gestation. Immediately after the first breeding season, a subset of controls and prenatal T-treated (TR) sheep were administered an insulin sensitizer (rosiglitazone; 8 mg/d) orally for 8 months. Untreated control and prenatal T-treated females (T group) were studied in parallel. Biochemical analyses revealed rosiglitazone to be safe for use in sheep. Glucose tolerance tests performed before and after the insulin sensitizer treatment found that insulin sensitizer decreased cumulative insulin, cumulative insulin/glucose ratio, and insulin area under the curve by about 50% and increased the insulin sensitivity index by about 70% in the TR compared with the T group. Twenty percent of TR females showed a reduced number of cycles in the second relative to first breeding season as opposed to 80% of T group females showing such deterioration. Insulin sensitizer treatment also decreased the number of aberrant cycles (>/=18 d) during the second breeding season in the TR group relative to the first as opposed to the T group females showing an increase in the second breeding season relative to the first. These findings provide evidence that insulin sensitizer treatment prevents further deterioration of the reproductive axis in prenatal T-treated sheep, a finding of translational relevance to women with polycystic ovary syndrome.

Oxytocin enhances pupil dilation and sensitivity to ‘hidden’ emotional expressions

PubMed Central

Wessberg, Johan; Ellingsen, Dan-Mikael; Chelnokova, Olga; Olausson, Håkan; Laeng, Bruno

2013-01-01

Sensing others’ emotions through subtle facial expressions is a highly important social skill. We investigated the effects of intranasal oxytocin treatment on the evaluation of explicit and ‘hidden’ emotional expressions and related the results to individual differences in sensitivity to others’ subtle expressions of anger and happiness. Forty healthy volunteers participated in this double-blind, placebo-controlled crossover study, which shows that a single dose of intranasal oxytocin (40 IU) enhanced or ‘sharpened’ evaluative processing of others’ positive and negative facial expression for both explicit and hidden emotional information. Our results point to mechanisms that could underpin oxytocin’s prosocial effects in humans. Importantly, individual differences in baseline emotional sensitivity predicted oxytocin’s effects on the ability to sense differences between faces with hidden emotional information. Participants with low emotional sensitivity showed greater oxytocin-induced improvement. These participants also showed larger task-related pupil dilation, suggesting that they also allocated the most attentional resources to the task. Overall, oxytocin treatment enhanced stimulus-induced pupil dilation, consistent with oxytocin enhancement of attention towards socially relevant stimuli. Since pupil dilation can be associated with increased attractiveness and approach behaviour, this effect could also represent a mechanism by which oxytocin increases human affiliation. PMID:22648957

Oxytocin enhances pupil dilation and sensitivity to 'hidden' emotional expressions.

PubMed

Leknes, Siri; Wessberg, Johan; Ellingsen, Dan-Mikael; Chelnokova, Olga; Olausson, Håkan; Laeng, Bruno

2013-10-01

Sensing others' emotions through subtle facial expressions is a highly important social skill. We investigated the effects of intranasal oxytocin treatment on the evaluation of explicit and 'hidden' emotional expressions and related the results to individual differences in sensitivity to others' subtle expressions of anger and happiness. Forty healthy volunteers participated in this double-blind, placebo-controlled crossover study, which shows that a single dose of intranasal oxytocin (40 IU) enhanced or 'sharpened' evaluative processing of others' positive and negative facial expression for both explicit and hidden emotional information. Our results point to mechanisms that could underpin oxytocin's prosocial effects in humans. Importantly, individual differences in baseline emotional sensitivity predicted oxytocin's effects on the ability to sense differences between faces with hidden emotional information. Participants with low emotional sensitivity showed greater oxytocin-induced improvement. These participants also showed larger task-related pupil dilation, suggesting that they also allocated the most attentional resources to the task. Overall, oxytocin treatment enhanced stimulus-induced pupil dilation, consistent with oxytocin enhancement of attention towards socially relevant stimuli. Since pupil dilation can be associated with increased attractiveness and approach behaviour, this effect could also represent a mechanism by which oxytocin increases human affiliation.

Highly sensitive torsion sensor based on long period fiber grating fabricated by femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Dong, Xinran; Xie, Zheng; Song, Yuxin; Yin, Kai; Luo, Zhi; Duan, Ji'an; Wang, Cong

2017-12-01

A highly sensitive torsion sensor based on long period fiber grating (LPFG) fabricated by 800 nm femtosecond laser pulses is proposed and demonstrated. LPFG with an attenuation depth of ∼14 dB is achieved within the wavelength range of 1425-1575 nm. The experiment results show that the LP02 and LP03 resonant wavelengths experience red-shift when the twist direction is clockwise while they occur blue-shift in the twist counterclockwise direction as the twist rate increases. However, the LP04 resonant wavelength is always shifted toward shorter wavelength independently of the twist directions and higher twist sensitivity is observed. In addition, the loss peak amplitude of LPFG shows a tendency to decrease with the twist rate increases whether the LPFG is twisted clockwise or counterclockwise. Meanwhile, the resonant wavelength occurs splitting phenomenon in the case of higher twist rate as well as the high order resonant wavelength performs more significantly. Additionally, the sensor shows a twist sensitivity as high as 118.7 pm/(rad/m) in the range of -105 to -52.5 rad/m and that of 181.7 pm/(rad/m) in the range of 52.5-105 rad/m.

Zebrafish embryotoxicity test for developmental (neuro)toxicity: Demo case of an integrated screening approach system using anti-epileptic drugs.

PubMed

Beker van Woudenberg, Anna; Snel, Cor; Rijkmans, Eke; de Groot, Didima; Bouma, Marga; Hermsen, Sanne; Piersma, Aldert; Menke, Aswin; Wolterbeek, André

2014-11-01

To improve the predictability of the zebrafish embryotoxicity test (ZET) for developmental (neuro)toxicity screening, we used a multiple-endpoints strategy, including morphology, motor activity (MA), histopathology and kinetics. The model compounds used were antiepileptic drugs (AEDs): valproic acid (VPA), carbamazepine (CBZ), ethosuximide (ETH) and levetiracetam (LEV). For VPA, histopathology was the most sensitive parameter, showing effects already at 60μM. For CBZ, morphology and MA were the most sensitive parameters, showing effects at 180μM. For ETH, all endpoints showed similar sensitivity (6.6mM), whereas MA was the most sensitive parameter for LEV (40mM). Inclusion of kinetics did not alter the absolute ranking of the compounds, but the relative potency was changed considerably. Taking all together, this demo-case study showed that inclusion of multiple-endpoints in ZET may increase the sensitivity of the assay, contribute to the elucidation of the mode of toxic action and to a better definition of the applicability domain of ZET. Copyright © 2014 Elsevier Inc. All rights reserved.

Design and introduction of a disulfide bridge in firefly luciferase: increase of thermostability and decrease of pH sensitivity.

PubMed

Imani, Mehdi; Hosseinkhani, Saman; Ahmadian, Shahin; Nazari, Mahboobeh

2010-08-01

The thermal sensitivity and pH-sensitive spectral properties of firefly luciferase have hampered its application in a variety of fields. It is proposed that the stability of a protein can be increased by introduction of disulfide bridge that decreases the configurational entropy of unfolding. A disulfide bridge is introduced into Photinus pyralis firefly luciferase to make two separate mutant enzymes with a single bridge. Even though the A103C/S121C mutant showed remarkable thermal stability, its specific activity decreased, whereas the A296C/A326C mutant showed tremendous thermal stability, relative pH insensitivity and 7.3-fold increase of specific activity. Moreover, the bioluminescence emission spectrum of A296C/A326C was resistant against higher temperatures (37 degrees C). Far-UV CD analysis showed slight secondary structure changes for both mutants. Thermal denaturation analysis showed that conformational stabilities of A103C/S121C and A296C/A326C are more than native firefly luciferase. It is proposed that since A296 and A326 are situated in the vicinity of the enzyme active site microenvironment in comparison with A103 and S121, the formation of a disulfide bridge in this region has more impact on enzyme kinetic characteristics.

Effects of Sodium Butyrate on Methamphetamine-Sensitized Locomotor Activity

PubMed Central

Harkness, John H.; Hitzemann, Robert J.; Edmunds, Stephanie; Phillips, Tamara J.

2012-01-01

Neuroadaptations associated with behavioral sensitization induced by repeated exposure to methamphetamine (MA) appear to be involved in compulsive drug pursuit and use. Increased histone acetylation, an epigenetic effect resulting in altered gene expression, may promote sensitized responses to psychostimulants. The role of histone acetylation in the expression and acquisition of MA-induced locomotor sensitization was examined by measuring the effect of histone deacetylase inhibition by sodium butyrate (NaB). For the effect on expression, vehicle or NaB (630 mg/kg, intraperitoneally) was administered 30 min prior to MA challenge in mice treated repeatedly with MA (10 days of 2 mg/kg MA) or saline (10 days), and then locomotor response to MA challenge was measured. NaB treatment increased the locomotor response to MA in both acutely MA treated and sensitized animals. For acquisition, NaB was administered 30 min prior to each MA exposure (10 days of 1 or 2 mg/kg), but not prior to the MA challenge test. Treatment with NaB during the sensitization acquisition period significantly increased locomotor activation by MA in sensitized mice only. NaB alone did not significantly alter locomotor activity. Acute NaB or MA, but not the combination, appeared to increase striatal acetylation at histone H4. Repeated treatment with MA, but not NaB or MA plus NaB, increased striatal acetylation at histone H3. Although increased histone acetylation may alter the expression of genes involved in acute locomotor response to MA and in the acquisition of MA-induced sensitization, results for acetylation at H3 and H4 showed little correspondence with behavior. PMID:23137698

State-dependent climate sensitivity in past warm climates and its implications for future climate projections.

PubMed

Caballero, Rodrigo; Huber, Matthew

2013-08-27

Projections of future climate depend critically on refined estimates of climate sensitivity. Recent progress in temperature proxies dramatically increases the magnitude of warming reconstructed from early Paleogene greenhouse climates and demands a close examination of the forcing and feedback mechanisms that maintained this warmth and the broad dynamic range that these paleoclimate records attest to. Here, we show that several complementary resolutions to these questions are possible in the context of model simulations using modern and early Paleogene configurations. We find that (i) changes in boundary conditions representative of slow "Earth system" feedbacks play an important role in maintaining elevated early Paleogene temperatures, (ii) radiative forcing by carbon dioxide deviates significantly from pure logarithmic behavior at concentrations relevant for simulation of the early Paleogene, and (iii) fast or "Charney" climate sensitivity in this model increases sharply as the climate warms. Thus, increased forcing and increased slow and fast sensitivity can all play a substantial role in maintaining early Paleogene warmth. This poses an equifinality problem: The same climate can be maintained by a different mix of these ingredients; however, at present, the mix cannot be constrained directly from climate proxy data. The implications of strongly state-dependent fast sensitivity reach far beyond the early Paleogene. The study of past warm climates may not narrow uncertainty in future climate projections in coming centuries because fast climate sensitivity may itself be state-dependent, but proxies and models are both consistent with significant increases in fast sensitivity with increasing temperature.

The Effects of HSP27 on Gemcitabine-Resistant Pancreatic Cancer Cell Line Through Snail.

PubMed

Zhang, Song; Zhang, Xiao-qi; Huang, Shu-ling; Chen, Min; Shen, Shan-shan; Ding, Xi-wei; Lv, Ying; Zou, Xiao-ping

2015-10-01

To evaluate the regulation mechanism of heat shock protein 27 (HSP27) on gemcitabine (GEM) resistance of pancreatic cancer cell. The expression vectors pEGFP-C1-HSP27 and the vectors of MicroRNA targeting Snail were introduced into GEM-sensitive pancreatic cancer SW1990 cells, and the vectors of small hairpin RNA targeting HSP27 were transfected into SW1990 and GEM-resistant SW1990/GEM cells. The expressions of HSP27, p-HSP27 (Ser82), Snail, ERCC1, and E-cadherin were evaluated by Western blotting. The sensitivity of transfected cells to GEM was detected by CCK-8 assay and Annexin V-FITC apoptosis assay. As compared to SW1990, SW1990/GEM showed significantly increased expressions of HSP27, p-HSP27, Snail and ERCC1 with decreased expression of E-cadherin. By increasing HSP27 expression, we found increase of Snail and ERCC1 with reduction of E-cadherin expressions, while reduction of HSP27 expression caused reduction of Snail and ERCC1 but increase of E-cadherin expressions. Downregulation of Snail resulted in the reduction of ERCC1 expression and increase of E-cadherin. Furthermore, downregulation of HSP27 or snail caused increased GEM sensitivity of pancreatic cancer cells, and upregulation of HSP27 showed the opposite results. There is an inverse correlation between HSP27 expression and GEM sensitivity of SW1990 cells, which might be realized by regulating E-cadherin and ERCC1 expressions through Snail.

Experimental study on the sensitive depth of backwards detected light in turbid media.

PubMed

Zhang, Yunyao; Huang, Liqing; Zhang, Ning; Tian, Heng; Zhu, Jingping

2018-05-28

In the recent past, optical spectroscopy and imaging methods for biomedical diagnosis and target enhancing have been widely researched. The challenge to improve the performance of these methods is to know the sensitive depth of the backwards detected light well. Former research mainly employed a Monte Carlo method to run simulations to statistically describe the light sensitive depth. An experimental method for investigating the sensitive depth was developed and is presented here. An absorption plate was employed to remove all the light that may have travelled deeper than the plate, leaving only the light which cannot reach the plate. By measuring the received backwards light intensity and the depth between the probe and the plate, the light intensity distribution along the depth dimension can be achieved. The depth with the maximum light intensity was recorded as the sensitive depth. The experimental results showed that the maximum light intensity was nearly the same in a short depth range. It could be deduced that the sensitive depth was a range, rather than a single depth. This sensitive depth range as well as its central depth increased consistently with the increasing source-detection distance. Relationships between sensitive depth and optical properties were also investigated. It also showed that the reduced scattering coefficient affects the central sensitive depth and the range of the sensitive depth more than the absorption coefficient, so they cannot be simply added as reduced distinct coefficients to describe the sensitive depth. This study provides an efficient method for investigation of sensitive depth. It may facilitate the development of spectroscopy and imaging techniques for biomedical diagnosis and underwater imaging.

Caudate neuronal recording in freely behaving animals following acute and chronic dose response methylphenidate exposure

PubMed Central

Claussen, Catherine M; Dafny, Nachum

2016-01-01

The misuse and abuse of the psychostimulant, methylphenidate (MPD) the drug of choice in the treatment of attention deficit hyperactivity disorder (ADHD) has seen a sharp uprising in recent years among both youth and adults for its cognitive enhancing effects and for recreational purposes. This uprise in illicit use has lead to many questions concerning the long term consequences of MPD exposure. The objective of this study was to record animal behavior concomitantly with the caudate nucleus (CN) neuronal activity following acute and repetitive (chronic) dose response exposure to methylphenidate (MPD). A saline control and three MPD dose (0.6, 2.5, and 10.0 mg/kg) groups were used. Behaviorally, the same MPD dose in some animals following chronic MPD exposure elicited behavioral sensitization and other animals elicited behavioral tolerance. Based on this finding, the CN neuronal population recorded from animals expressing behavioral sensitization were also evaluated separately from CN neurons recorded from animals expressing behavioral tolerance to chronic MPD exposure, respectively. Significant differences in CN neuronal population responses between the behaviorally sensitized and the behaviorally tolerant animals was observed for the 2.5 and 10.0 mg/kg MPD exposed groups. For 2.5 mg/kg MPD, behaviorally sensitized animals responded by decreasing their firing rates while behaviorally tolerant animals showed mainly an increase in their firing rates. The CN neuronal responses recorded from the behaviorally sensitized animals following 10.0 mg/kg MPD responded by increasing their firing rates whereas the CN neuronal recordings from the behaviorally tolerant animals showed that approximately half decreased their firing rates in response to 10.0 mg/kg MPD exposure. The comparison of percentage change in neuronal firing rates showed that the behaviorally tolerant animals trended to exhibit increases in their neuronal firing rates at ED1 following initial MPD exposure and oppositely at ED10 MPD rechallenge. While the behaviorally sensitized animals in general increased in their percentage change of firing rats were observed following acute 10.0 mg/kg MPD and the behaviorally sensitized 10.0 mg/kg MPD animals and a robust increase in neuronal firing rates at ED1 and ED10 rechallenge. These results suggest the need to first individually analyze animal behavioral activity, and than to evaluate the neuronal responses to the drug based on the animals behavioral response to chronic MPD exposure. PMID:26101057

High sensitivity knitted fabric strain sensors

NASA Astrophysics Data System (ADS)

Xie, Juan; Long, Hairu; Miao, Menghe

2016-10-01

Wearable sensors are increasingly used in smart garments for detecting and transferring vital signals and body posture, movement and respiration. Existing fabric strain sensors made from metallized yarns have low sensitivity, poor comfort and low durability to washing. Here we report a knitted fabric strain sensor made from a cotton/stainless steel (SS) fibre blended yarn which shows much higher sensitivity than sensors knitted from metallized yarns. The fabric feels softer than pure cotton textiles owing to the ultrafine stainless steel fibres and does not lose its electrical property after washing. The reason for the high sensitivity of the cotton/SS knitted fabric sensor was explored by comparing its sensing mechanism with the knitted fabric sensor made from metallized yarns. The results show that the cotton/SS yarn-to-yarn contact resistance is highly sensitive to strain applied to hooked yarn loops.

Electrical characterization of dye sensitized nano solar cell using natural pomegranate juice as photosensitizer

NASA Astrophysics Data System (ADS)

Adithi, U.; Thomas, Sara; Uma, V.; Pradeep, N.

2013-02-01

This paper shows Electrical characterization of Dye Sensitized Solar Cell using natural dye, extracted from the pomegranate as a photo sensitizer and ZnO nanoparticles as semiconductor. The constituents of fabricated dye sensitized solar cell were working electrode, dye, electrolyte and counter electrode. ZnO nanoparticles were synthesized and used as semiconductor in working electrode. Carbon soot was used as counter electrode. The resistance of ZnO film on ITO film was found out. There was an increase in the resistance of the film and film changes from conducting to semiconducting. Photovoltaic parameters of the fabricated cell like Short circuit current, open circuit voltage, Fill factor and Efficiency were found out. This paper shows that usage of natural dyes like pomegranate juice as sensitizer enables faster and simpler production of cheaper and environmental friendly solar cell.

Enhanced H2 sensitivity at room temperature of ZnO nanowires functionalized by Pd nanoparticles

NASA Astrophysics Data System (ADS)

Ren, Shoutian; Fan, Guanghua; Qu, Shiliang; Wang, Qiang

2011-10-01

For sensitive detection of H2, ZnO nanowires networks decorated with photo-decomposed Pd nanoparticles were fabricated between femtosecond laser-writing interdigitated electrodes by chemical vapor deposition method. When H2 concentration is increased from 20 to 4000 ppm at room temperature, sensitivity of the sample is increased from 3.7% to 1017.9%. The high sensitivity can be explained by considering the reaction between the adsorbed O2- and the disassociated H atoms facilitated by Pd nanoparticles. This mechanism is further supported by the H2 response results under UV light illumination, which can reduce the amount of O2- on the ZnO surface, leading to depressed sensitivity. The sensor also shows high selectivity, long-term stability, and ultra-low power consumption of nanowatt level, due to the novel fabrication process.

Age, strain, and gender as factors for increased sensitivity of the mouse lung to inhaled ozone

EPA Science Inventory

Ozone (O(3)) is a respiratory irritant that leads to airway inflammation and pulmonary dysfunction. Animal studies show that neonates are more sensitive to O(3) inhalation than adults, and children represent a potentially susceptible population. This latter notion is not well est...

Morphology-Driven Control of Metabolite Selectivity Using Nanostructure-Initiator Mass Spectrometry

DOE PAGES

Gao, Jian; Louie, Katherine B.; Steinke, Philipp; ...

2017-05-26

Nanostructure-initiator mass spectrometry (NIMS) is a laser desorption/ionization analysis technique based on the vaporization of a nanostructure-trapped liquid "initiator" phase. Here we report an intriguing relationship between NIMS surface morphology and analyte selectivity. Scanning electron microscopy and spectroscopic ellipsometry were used to characterize the surface morphologies of a series of NIMS substrates generated by anodic electrochemical etching. Mass spectrometry imaging was applied to compare NIMS sensitivity of these various surfaces toward the analysis of diverse analytes. The porosity of NIMS surfaces was found to increase linearly with etching time where the pore size ranged from 4 to 12 nm withmore » corresponding porosities estimated to be 7-70%. Surface morphology was found to significantly and selectively alter NIMS sensitivity. The small molecule ( < 2k Da) sensitivity was found to increase with increased porosity, whereas low porosity had the highest sensitivity for the largest molecules examined. Estimation of molecular sizes showed that this transition occurs when the pore size is < 3× the maximum of molecular dimensions. While the origins of selectivity are unclear, increased signal from small molecules with increased surface area is consistent with a surface area restructuring-driven desorption/ionization process where signal intensity increases with porosity. In contrast, large molecules show highest signal for the low-porosity and small-pore-size surfaces. We attribute this to strong interactions between the initiator-coated pore structures and large molecules that hinder desorption/ionization by trapping large molecules. This finding may enable us to design NIMS surfaces with increased specificity to molecules of interest.« less

Skew Projection of Echo-Detected EPR Spectra for Increased Sensitivity and Resolution

PubMed Central

Bowman, Michael K.; Krzyaniak, Matthew D.; Cruce, Alex A.; Weber, Ralph T.

2013-01-01

The measurement of EPR spectra during pulsed EPR experiments is commonly accomplished by recording the integral of the electron spin echo as the applied magnetic field is stepped through the spectrum. This approach to echo-detected EPR spectral measurement (ED-EPR) limits sensitivity and spectral resolution and can cause gross distortions in the resulting spectra because some of the information present in the electron spin echo is discarded in such measurements. However, Fourier Transformation of echo shapes measured at a series of magnetic field values followed by skew projection onto either a magnetic field or resonance frequency axis can increase both spectral resolution and sensitivity without the need to trade one against the other. Examples of skew-projected spectra with single crystals, glasses and powders show resolution improvements as large as a factor of seven with sensitivity increases of as much as a factor of five. PMID:23644351

Skew projection of echo-detected EPR spectra for increased sensitivity and resolution

NASA Astrophysics Data System (ADS)

Bowman, Michael K.; Krzyaniak, Matthew D.; Cruce, Alex A.; Weber, Ralph T.

2013-06-01

The measurement of EPR spectra during pulsed EPR experiments is commonly accomplished by recording the integral of the electron spin echo as the applied magnetic field is stepped through the spectrum. This approach to echo-detected EPR spectral measurement (ED-EPR) limits sensitivity and spectral resolution and can cause gross distortions in the resulting spectra because some of the information present in the electron spin echo is discarded in such measurements. However, Fourier transformation of echo shapes measured at a series of magnetic field values followed by skew projection onto either a magnetic field or resonance frequency axis can increase both spectral resolution and sensitivity without the need to trade one against the other. Examples of skew-projected spectra with single crystals, glasses and powders show resolution improvements as large as a factor of seven with sensitivity increases of as much as a factor of five.

Developmental priming of stomatal sensitivity to abscisic acid by leaf microclimate.

PubMed

Pantin, Florent; Renaud, Jeanne; Barbier, François; Vavasseur, Alain; Le Thiec, Didier; Rose, Christophe; Bariac, Thierry; Casson, Stuart; McLachlan, Deirdre H; Hetherington, Alistair M; Muller, Bertrand; Simonneau, Thierry

2013-09-23

Plant water loss and CO2 uptake are controlled by valve-like structures on the leaf surface known as stomata. Stomatal aperture is regulated by hormonal and environmental signals. We show here that stomatal sensitivity to the drought hormone abscisic acid (ABA) is acquired during leaf development by exposure to an increasingly dryer atmosphere in the rosette plant Arabidopsis. Young leaves, which develop in the center of the rosette, do not close in response to ABA. As the leaves increase in size, they are naturally exposed to increasingly dry air as a consequence of the spatial arrangement of the leaves, and this triggers the acquisition of ABA sensitivity. Interestingly, stomatal ABA sensitivity in young leaves is rapidly restored upon water stress. These findings shed new light on how plant architecture and stomatal physiology have coevolved to optimize carbon gain against water loss in stressing environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

Intertrial-interval effects on sensitivity (A') and response bias (B") in a temporal discrimination by rats.

PubMed Central

Raslear, T G; Shurtleff, D; Simmons, L

1992-01-01

Killeen and Fetterman's (1988) behavioral theory of animal timing predicts that decreases in the rate of reinforcement should produce decreases in the sensitivity (A') of temporal discriminations and a decrease in miss and correct rejection rates (decrease in bias toward "long" responses). Eight rats were trained on a 10- versus 0.1-s temporal discrimination with an intertrial interval of 5 s and were subsequently tested on probe days on the same discrimination with intertrial intervals of 1, 2.5, 5, 10, or 20 s. The rate of reinforcement declined for all animals as intertrial interval increased. Although sensitivity (A') decreased with increasing intertrial interval, all rats showed an increase in bias to make long responses. PMID:1447544

Evaluation of the bioNexia Legionella Test, Including Impact of Incubation Time Extension, for Detection of Legionella pneumophila Serogroup 1 Antigen in Urine.

PubMed

Badoux, Paul; Euser, Sjoerd M; Bruin, Jacob P; Mulder, Patrick P G; Yzerman, Ed P F

2017-06-01

In this study, we compared the bioNexia test (bioMérieux, Marcy-l'Étoile, France), a new immunochromatographic assay for the detection of Legionella pneumophila serogroup 1 in urine, with the BinaxNOW urinary antigen test (Alere, Waltham, Massachusetts, USA). After 15 min of incubation (in accordance with the manufacturers' instructions), the sensitivities and specificities were, respectively, 76.5% and 97.2% for the bioNexia test and 87.1% and 100% for the BinaxNOW test. After a prolonged incubation time of 60 min, the sensitivities and specificities increased to, respectively, 89.4% and 97.2% for the bioNexia test and 91.8% and 100% for the BinaxNOW test. When the tests were read after 15 min, the concentration of discrepant urine samples increased the sensitivities to 94.1% for both tests. In conclusion, we found that although the bioNexia test showed lower sensitivity for the detection of L. pneumophila antigen in nonconcentrated urine compared to the BinaxNOW test, a prolonged incubation time as well as the use of concentrated samples showed comparable sensitivities for both tests. Copyright © 2017 American Society for Microbiology.

Human sex differences in emotional processing of own-race and other-race faces.

PubMed

Ran, Guangming; Chen, Xu; Pan, Yangu

2014-06-18

There is evidence that women and men show differences in the perception of affective facial expressions. However, none of the previous studies directly investigated sex differences in emotional processing of own-race and other-race faces. The current study addressed this issue using high time resolution event-related potential techniques. In total, data from 25 participants (13 women and 12 men) were analyzed. It was found that women showed increased N170 amplitudes to negative White faces compared with negative Chinese faces over the right hemisphere electrodes. This result suggests that women show enhanced sensitivity to other-race faces showing negative emotions (fear or disgust), which may contribute toward evolution. However, the current data showed that men had increased N170 amplitudes to happy Chinese versus happy White faces over the left hemisphere electrodes, indicating that men show enhanced sensitivity to own-race faces showing positive emotions (happiness). In this respect, men might use past pleasant emotional experiences to boost recognition of own-race faces.

Methamphetamine-sensitized rats show augmented dopamine release to methylphenidate stimulation: a positron emission tomography using [18F]fallypride.

PubMed

Ota, Miho; Ogawa, Shintaro; Kato, Koichi; Wakabayashi, Chisato; Kunugi, Hiroshi

2015-04-30

Previous studies demonstrated that patients with schizophrenia show greater sensitivity to psychostimulants than healthy subjects. Sensitization to psychostimulants and resultant alteration of dopaminergic neurotransmission in rodents have been suggested as a useful model of schizophrenia. This study was aimed to examine the use of methylphenidate as a psychostimulant to induce dopamine release and that of [18F]fallypride as a radioligand to estimate the release in a rat model of schizophrenia. Six rats were scanned by positron emission tomography (PET) twice before and after methylphenidate challenge to evaluate dopamine release. After the scans, these rats were sensitized by using repeated methamphetamine (MAP) administration. Then, they were re-scanned twice again before and after methylphenidate challenge to evaluate whether MAP-sensitized rats show greater sensitivity to methylphenidate. We revealed a main effect of MAP-pretreatment and that of metylphenidate challenge. We found that % change of distribution volume ratio after repeated administration of MAP was greater than that before sensitization. These results suggest that methylphenidate-induced striatal dopamine release increased after sensitization to MAP. PET scan using [18F]fallypride at methylphenidate-challenge may provide a biological marker for schizophrenia and be useful to diagnose schizophrenia. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Sensitivity analysis of hydrodynamic stability operators

NASA Technical Reports Server (NTRS)

Schmid, Peter J.; Henningson, Dan S.; Khorrami, Mehdi R.; Malik, Mujeeb R.

1992-01-01

The eigenvalue sensitivity for hydrodynamic stability operators is investigated. Classical matrix perturbation techniques as well as the concept of epsilon-pseudoeigenvalues are applied to show that parts of the spectrum are highly sensitive to small perturbations. Applications are drawn from incompressible plane Couette, trailing line vortex flow and compressible Blasius boundary layer flow. Parametric studies indicate a monotonically increasing effect of the Reynolds number on the sensitivity. The phenomenon of eigenvalue sensitivity is due to the non-normality of the operators and their discrete matrix analogs and may be associated with large transient growth of the corresponding initial value problem.

Early detection of response to radiation therapy in patients with brain malignancies using conventional and high b-value diffusion-weighted magnetic resonance imaging.

PubMed

Mardor, Yael; Pfeffer, Raphael; Spiegelmann, Roberto; Roth, Yiftach; Maier, Stephan E; Nissim, Ouzi; Berger, Raanan; Glicksman, Ami; Baram, Jacob; Orenstein, Arie; Cohen, Jack S; Tichler, Thomas

2003-03-15

To study the feasibility of using diffusion-weighted magnetic resonance imaging (DWMRI), which is sensitive to the diffusion of water molecules in tissues, for detection of early tumor response to radiation therapy; and to evaluate the additional information obtained from high DWMRI, which is more sensitive to low-mobility water molecules (such as intracellular or bound water), in increasing the sensitivity to response. Standard MRI and DWMRI were acquired before and at regular intervals after initiating radiation therapy for 10 malignant brain lesions in eight patients. One week posttherapy, three of six responding lesions showed an increase in the conventional DWMRI parameters. Another three responding lesions showed no change. Four nonresponding lesions showed a decrease or no change. The early change in the diffusion parameters was enhanced by using high DWMRI. When high DWMRI was used, all responding lesions showed increase in the diffusion parameter and all nonresponding lesions showed no change or decrease. Response was determined by standard MRI 7 weeks posttherapy. The changes in the diffusion parameters measured 1 week after initiating treatment were correlated with later tumor response or no response (P <.006). This correlation was increased to P <.0006 when high DWMRI was used. The significant correlation between changes in diffusion parameters 1 week after initiating treatment and later tumor response or no response suggests the feasibility of using DWMRI for early, noninvasive prediction of tumor response. The ability to predict response may enable early termination of treatment in nonresponding patients, prevent additional toxicity, and allow for early changes in treatment.

A new room temperature gas sensor based on pigment-sensitized TiO2 thin film for amines determination.

PubMed

Yanxiao, Li; Xiao-bo, Zou; Xiao-wei, Huang; Ji-yong, Shi; Jie-wen, Zhao; Holmes, Mel; Hao, Limin

2015-05-15

A new room temperature gas sensor was fabricated with pigment-sensitized TiO2 thin film as the sensing layer. Four natural pigments were extracted from spinach (Spinacia oleracea), red radish (Raphanus sativus L), winter jasmine (Jasminum nudiflorum), and black rice (Oryza sativa L. indica) by ethanol. Natural pigment-sensitized TiO2 sensor was prepared by immersing porous TiO2 films in an ethanol solution containing a natural pigment for 24h. The hybrid organic-inorganic formed films here were firstly exposed to atmospheres containing methylamine vapours with concentrations over the range 2-10 ppm at room temperature. The films sensitized by the pigments from black-rice showed an excellent gas-sensitivity to methylamine among the four natural pigments sensitized films due to the anthocyanins. The relative change resistance, S, of the films increased almost linearly with increasing concentrations of methylamine (r=0.931). At last, the black rice pigment sensitized TiO2 thin film was used to determine the biogenic amines generated by pork during storage. The developed films had good sensitivity to analogous gases such as putrscine, and cadaverine that will increase during storage. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of a prolonged endurance marathon on vascular endothelial and inflammation markers in runners with exercise-induced hypertension.

PubMed

Jee, Haemi; Park, Jaehyun; Oh, Jae-Gun; Lee, Yoon-Hee; Shin, Kyung-A; Kim, Young-Joo

2013-06-01

The aim of this study was to observe the changes in endothelial and inflammatory markers in middle-aged male runners with exercise-induced hypertension (EIH) at baseline and at 100-km, 200-km, and 308-km checkpoints during a prolonged endurance ultramarathon. Among a total of 62 ultramarathon volunteers, 8 with systolic blood pressure higher than 210 mm Hg and 8 with normal systolic blood pressure were selected for this study. The subjects were designated to EIH and control (CON) groups. Blood was collected for the analysis of soluble vascular cell adhesion molecule-1, soluble E-selectin, leukocytes, creatine kinase, and high-sensitivity C-reactive protein. Soluble vascular cell adhesion molecule-1 showed a significantly greater increase in the EIH group than in the CON group at 100 km and 200 km. Soluble E-selectin also showed a significantly greater increase in the EIH group than in the CON group at 100 km. Leukocytes significantly increased in the EIH group than in the CON group at 308 km. Creatine kinase and high-sensitivity C-reactive protein showed no group differences. Leukocytes, creatine kinase, and high-sensitivity C-reactive protein showed delayed-onset increases in both groups. Increased exercise intensity may stimulate greater endothelial responses independent of the inflammatory markers in EIH. The loss of a protective effect may be greater in those with EIH than in CONs. Acknowledging and prescribing proper exercise intensity may be critical in preventing possible vascular-related complications in runners with EIH.

A fiber Bragg grating--bimetal temperature sensor for solar panel inverters.

PubMed

Ismail, Mohd Afiq; Tamchek, Nizam; Hassan, Muhammad Rosdi Abu; Dambul, Katrina D; Selvaraj, Jeyrai; Rahim, Nasrudin Abd; Sandoghchi, Reza; Adikan, Faisal Rafiq Mahamd

2011-01-01

This paper reports the design, characterization and implementation of a fiber Bragg grating (FBG)-based temperature sensor for an insulted-gate Bipolar transistor (IGBT) in a solar panel inverter. The FBG is bonded to the higher coefficient of thermal expansion (CTE) side of a bimetallic strip to increase its sensitivity. Characterization results show a linear relationship between increasing temperature and the wavelength shift. It is found that the sensitivity of the sensor can be categorized into three characterization temperature regions between 26 °C and 90 °C. The region from 41 °C to 90 °C shows the highest sensitivity, with a value of 14 pm/°C. A new empirical model that considers both temperature and strain effects has been developed for the sensor. Finally, the FBG-bimetal temperature sensor is placed in a solar panel inverter and results confirm that it can be used for real-time monitoring of the IGBT temperature.

3-Bromopyruvate enhances TRAIL-induced apoptosis in human nasopharyngeal carcinoma cells through CHOP-dependent upregulation of TRAIL-R2.

PubMed

Can, Zhou; Lele, Song; Zhirui, Zhang; Qiong, Pan; Yuzhong, Chen; Lingling, Liu; Surong, Zhao; Yiming, Sun; Pei, Zhang; Chenchen, Jiang; Liu, Hao

2017-08-01

Past reports have shown that the sensitivity of cancer cells to TRAIL-induced apoptosis is related to their expression of TRAIL-death receptors on the cell surface. However, the level of TRAIL-death receptors expression on cancer cells is always low. Our previous research showed that nasopharyngeal carcinoma (NPC) cells have a poor sensitivity to low doses of TRAIL. Here, we evaluated combined treatment with the energy inhibitor 3-bromopyruvate (3BP) and TRAIL as a method to produce an increased apoptotic response in NPC cells. The results showed that 3BP and TRAIL together produced higher cytotoxicity and increased TRAIL-R2 expression in NPC cells compared with the effects of either 3BP or TRAIL alone. These findings led us to hypothesize that 3BP may sensitize NPC cells to TRAIL. 3BP is a metabolic blocker that inhibits hexokinase II activity, suppresses ATP production, and induces endoplasmic reticulum (ER) stress. Our results showed that 3BP also activated AMP-activated protein kinase, which we found to play an important role in the induction of ER stress by 3BP. Furthermore, the induction of TRAIL-R2 expression and the sensitization of the NPC cells to TRAIL by 3BP were reduced when we inhibited the expression of CHOP. Taken together, our results showed that a low dose of 3BP sensitized NPC cells to TRAIL-induced apoptosis by the upregulation of CHOP, which was mediated by the activation of AMP-activated protein kinase and ER stress. The results showed that 3BP is a promising candidate agent for enhancing the therapeutic response to TRAIL in NPC.

Increase in sensitization to oil of turpentine: recent data from a multicenter study on 45,005 patients from the German-Austrian Information Network of Departments of Dermatology (IVDK).

PubMed

Treudler, R; Richter, G; Geier, J; Schnuch, A; Orfanos, C E; Tebbe, B

2000-02-01

Contact allergy to oil of turpentine was reported to have become rare. However, the evaluation of standardized data of 45,005 patients tested 1992-1997 in 30 Dermatological Centers associated with the German-Austrian Information Network of Departments of Dermatology (IVDK) showed an increase in positive patch test reactions to turpentine from 0.5% during the years 1992-1995, up to 1.7% in 1996 and 3.1% in 1997. In particular, 17,347 patients tested in 1996-1997 were evaluated in detail by comparing 431 individuals with positive patch test reactions with the rest of the group found negative to turpentine. Using the so-called MOAHLFA index, the following characteristics were shown. Turpentine allergy (a) was found to be significantly less frequent in men and in patients with occupational dermatitis, (b) showed no difference in its association with atopic dermatitis, (c) patients with turpentine allergy had significantly less symptoms of the hands, more symptoms of the legs or in the face and (d) were significantly more often aged over 60 years. Also, patients sensitized to turpentine had increased rates of additional sensitizations. The definite reason for the increase in turpentine sensitization in the population tested here is not clear. Therefore, a detailed exposure analysis is necessary; the new increase in turpentine allergies may be due to popular topical remedies or household chemicals.

Ozone in the southeastern United States: An observation-based model using measurements from the SEARCH network

NASA Astrophysics Data System (ADS)

Blanchard, C. L.; Hidy, G. M.; Tanenbaum, S.

2014-05-01

A generalized additive model (GAM) is used to examine the influence of meteorological factors, nitrogen oxides (NOx = NO + NO2), and non-methane hydrocarbons (NMOC) on daily peak 8-h ozone (O3) concentrations. Application to 2002-2011 monitoring data from the Southeastern Aerosol Research and Characterization (SEARCH) program showed sensitivity of peak 8-h O3 to morning concentrations of nitric oxide (NO) and nitrogen dioxide (NO2) and to afternoon concentrations of NO2 reaction products (NOz). Peak O3 decreased with increasing NO and increased with increasing NO2 concentrations, consistent with reactions involving O3, NO, and NO2. Ozone production efficiency (OPE), estimated from the modeled relation between peak 8-h O3 and afternoon NOz, was ˜40-100 percent higher at rural compared to urban sites. OPE was nonlinear at all sites, decreasing with increasing NOz concentration. The mean ratio of NOz/NOy showed a two-fold increase from urban to rural sites, associated with chemical aging in stagnant air masses from one day (urban sites) to two or more days (non-urban sites). Peak 8-h O3 concentrations in Atlanta were sensitive to concentrations of both non-biogenic NMOC and NOz. Non-urban Yorkville, Georgia, peak 8-h O3 concentrations were sensitive to NOz but not to non-biogenic NMOC concentrations. The results are consistent with expected NMOC and NOx sensitivity in urban and non-urban locales.

Comparative influence of propranolol and verapamil on glycemic control and histamine sensitivity associated with L-thyroxine-induced hyperthyroidism - an experimental study.

PubMed

Bhatt, Parloop A; Makwana, Dharmesh

2008-02-01

The present investigation was undertaken to study the comparative effectiveness of beta-adrenergic antagonist propranolol and calcium channel blocker verapamil on L-thyroxine-induced alteration on glycemic control and histamine sensitivity on rats and guinea pigs, respectively. Injection of L-thyroxine sodium every alternate day for 3 weeks in guinea pigs (75 microg/kg, i.p.) and rats (75 mg/kg, s.c.) produced a condition similar to thyrotoxicosis. Verapamil and propranolol administered daily in the third week along with L-thyroxine to two separate groups of hyperthyroid animals reversed thyroxine-induced loss in body weight, reduction in serum TSH levels, and rise in body temperature. Effect on glucose metabolism and insulin sensitivity was studied on rats. Compared to normal rats, L-thyroxine-treated animals showed a state of hyperglycemia, hyperinsulinemia, impaired glucose tolerance, and insulin resistance. Propranolol (10 mg/kg, i.p.) treatment significantly decreased fasting serum glucose levels without affecting serum insulin levels, AUC glucose, and K(ITT) values. Treatment with verapamil (5 mg/kg, i.p.) significantly reduced fasting serum glucose and insulin levels, AUC glucose, and significantly increased K(ITT) values. Effect of propranolol (15 mg/kg, orally) and verapamil (20 mg/kg, orally) treatment on histamine sensitivity was studied on L-thyroxine-treated guinea pigs. Compared to normal guinea pigs, L-thyroxine-treated guinea pigs showed an increased sensitivity to histamine-induced asphyxia. Verapamil treatment reversed this increased histamine sensitivity while propranolol aggravated it. In conclusion, compared to propranolol, verapamil has advantageous effects on glucose metabolism, insulin and histamine sensitivity and could therefore be a valuable addition as an adjunctive therapy option currently available for thyrotoxicosis associated with diabetes and/or anaphylaxis.

The effect of sildenafil citrate (Viagra) on visual sensitivity.

PubMed

Stockman, Andrew; Sharpe, Lindsay T; Tufail, Adnan; Kell, Philip D; Ripamonti, Caterina; Jeffery, Glen

2007-06-08

The erectile dysfunction medicine sildenafil citrate (Viagra) inhibits phosphodiesterase type 6 (PDE6), an essential enzyme involved in the activation and modulation of the phototransduction cascade. Although Viagra might thus be expected to impair visual performance, reports of deficits following its ingestion have so far been largely inconclusive or anecdotal. Here, we adopt tests sensitive to the slowing of the visual response likely to result from the inhibition of PDE6. We measured temporal acuity (critical fusion frequency) and modulation sensitivity in four subjects before and after the ingestion of a 100-mg dose of Viagra under conditions chosen to isolate the responses of either their short-wavelength-sensitive (S-) cone photoreceptors or their long- and middle-wavelength-sensitive (L- and M-) cones. When vision was mediated by S-cones, all subjects exhibited some statistically significant losses in sensitivity, which varied from mild to moderate. The two individuals who showed the largest S-cone sensitivity losses also showed comparable losses when their vision was mediated by the L- and M-cones. Some of the losses appear to increase with frequency, which is broadly consistent with Viagra interfering with the ability of PDE6 to shorten the time over which the visual system integrates signals as the light level increases. However, others appear to represent a roughly frequency-independent attenuation of the visual signal, which might also be consistent with Viagra lengthening the integration time (because it has the effect of increasing the effectiveness of steady background lights), but such changes are also open to other interpretations. Even for the more affected observers, however, Viagra is unlikely to impair common visual tasks, except under conditions of reduced visibility when objects are already near visual threshold.

Screening for alcohol use disorders and at-risk drinking in the general population: psychometric performance of three questionnaires.

PubMed

Rumpf, Hans-Jürgen; Hapke, Ulfert; Meyer, Christian; John, Ulrich

2002-01-01

Most screening questionnaires are developed in clinical settings and there are few data on their performance in the general population. This study provides data on the area under the receiver-operating characteristic (ROC) curve, sensitivity, specificity, and internal consistency of the Alcohol Use Disorders Identification Test (AUDIT), the consumption questions of the AUDIT (AUDIT-C) and the Lübeck Alcohol Dependence and Abuse Screening Test (LAST) among current drinkers (n = 3551) of a general population sample in northern Germany. Alcohol dependence and misuse according to DSM-IV and at-risk drinking served as gold standards to assess sensitivity and specificity and were assessed with the Munich-Composite Diagnostic Interview (M-CIDI). AUDIT and LAST showed insufficient sensitivity for at-risk drinking and alcohol misuse using standard cut-off scores, but satisfactory detection rates for alcohol dependence. The AUDIT-C showed low specificity in all criterion groups with standard cut-off. Adjusted cut-points are recommended. Among a subsample of individuals with previous general hospital admission in the last year, all questionnaires showed higher internal consistency suggesting lower reliability in non-clinical samples. In logistic regression analyses, having had a hospital admission increased the sensitivity in detecting any criterion group of the LAST, and the number of recent general practice visits increased the sensitivity of the AUDIT in detecting alcohol misuse. Women showed lower scores and larger areas under the ROC curves. It is concluded that setting specific instruments (e.g. primary care or general population) or adjusted cut-offs should be used.

State-dependent climate sensitivity in past warm climates and its implications for future climate projections

PubMed Central

Caballero, Rodrigo; Huber, Matthew

2013-01-01

Projections of future climate depend critically on refined estimates of climate sensitivity. Recent progress in temperature proxies dramatically increases the magnitude of warming reconstructed from early Paleogene greenhouse climates and demands a close examination of the forcing and feedback mechanisms that maintained this warmth and the broad dynamic range that these paleoclimate records attest to. Here, we show that several complementary resolutions to these questions are possible in the context of model simulations using modern and early Paleogene configurations. We find that (i) changes in boundary conditions representative of slow “Earth system” feedbacks play an important role in maintaining elevated early Paleogene temperatures, (ii) radiative forcing by carbon dioxide deviates significantly from pure logarithmic behavior at concentrations relevant for simulation of the early Paleogene, and (iii) fast or “Charney” climate sensitivity in this model increases sharply as the climate warms. Thus, increased forcing and increased slow and fast sensitivity can all play a substantial role in maintaining early Paleogene warmth. This poses an equifinality problem: The same climate can be maintained by a different mix of these ingredients; however, at present, the mix cannot be constrained directly from climate proxy data. The implications of strongly state-dependent fast sensitivity reach far beyond the early Paleogene. The study of past warm climates may not narrow uncertainty in future climate projections in coming centuries because fast climate sensitivity may itself be state-dependent, but proxies and models are both consistent with significant increases in fast sensitivity with increasing temperature. PMID:23918397

Stronger cortisol response to acute psychosocial stress is correlated with larger decrease in temporal sensitivity

PubMed Central

Yao, Zhuxi; Jiang, Caihong; Zhang, Kan; Wu, Jianhui

2016-01-01

As a fundamental dimension of cognition and behavior, time perception has been found to be sensitive to stress. However, how one’s time perception changes with responses to stress is still unclear. The present study aimed to investigate the relationship between stress-induced cortisol response and time perception. A group of 40 healthy young male adults performed a temporal bisection task before and after the Trier Social Stress Test for a stress condition. A control group of 27 male participants completed the same time perception task without stress induction. In the temporal bisection task, participants were first presented with short (400 ms) and long (1,600 ms) visual signals serving as anchor durations and then required to judge whether the intermediate probe durations were more similar to the short or the long anchor. The bisection point and Weber ratio were calculated and indicated the subjective duration and the temporal sensitivity, respectively. Data showed that participants in the stress group had significantly increased salivary cortisol levels, heart rates, and negative affects compared with those in the control group. The results did not show significant group differences for the subjective duration or the temporal sensitivity. However, the results showed a significant positive correlation between stress-induced cortisol responses and decreases in temporal sensitivity indexed by increases in the Weber ratio. This correlation was not observed for the control group. Changes in subjective duration indexed by temporal bisection points were not correlated with cortisol reactivity in both the groups. In conclusion, the present study found that although no significant change was observed in time perception after an acute stressor on the group-level comparison (i.e., stress vs. nonstress group), individuals with stronger cortisol responses to stress showed a larger decrease in temporal sensitivity. This finding may provide insight into the understanding of the relationship between stress and temporal sensitivity. PMID:27257544

Enhanced Area of Secondary Hyperalgesia in Women with Multiple Stressful Life Events: A Pilot Study.

PubMed

You, Dokyoung S; Creech, Suzannah K; Meagher, Mary W

2016-10-01

Stressful life events are associated with increased pain severity and chronicity. However, the mechanism underlying this association remains disputed. Recent animal studies suggest that chronic stress increases pain sensitivity and persistence by enhancing peripheral and central sensitization mechanisms. To test this hypothesis in humans, the authors examined whether sensitization is enhanced in healthy women reporting more stressful life events using the topical capsaicin test. Thirty-two healthy young women reporting varying levels of stressful life events were invited for laboratory pain testing. Capsaicin was applied topically to the volar forearm. Measurements included capsaicin-induced spontaneous pain and area of secondary hyperalgesia in the region surrounding capsaicin application. Physiological (heart rate and skin conductance) and self-reported affective (emotional valence and arousal) states were also measured. The results indicate that more stressful life events predicted a linear increase in the area of secondary hyperalgesia (β = 0.40, p = 0.023, R 2 = 0.16), but not the intensity of secondary hyperalgesia nor capsaicin-induced spontaneous pain. These findings suggest that life stressors may be associated with heightened central sensitization manifested by an increased area of secondary hyperalgesia. Additionally, life stressors were related to greater sympathetic cardiac, but not to affective responses to capsaicin-induced pain. This study shows that women reporting more stressful life events show a larger area of secondary mechanical hyperalgesia. These preliminary findings suggest that life stressors may facilitate pain processing by enhancing central sensitization. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Chemical crosslinking of acrylic acid to form biocompatible pH sensitive hydrogel reinforced with cellulose nanocrystals (CNC)

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

Lim, Lim Sze; Ahmad, Ishak; Lazim, Mohd Azwani Shah Mat

2014-09-03

The purpose of this study is to produce a novel pH and temperature sensitive hydrogel, composed of poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali and bleaching treatments followed by acid hydrolysis. The PAA was then subjected to chemical cross-linking using the cross-linking agent (N,N-methylenebisacrylamide) with CNC entrapped in PAA matrix. The mixture was casted onto petri dish to obtain disc shape hydrogel. The effects of reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH and temperature were studied.more » The obtained hydrogel was further subjected to different tests such swelling test for swelling behaviour at different pH and temperature along with scanning electron microscopy (SEM) for morphology analysis. The hydrogel obtained showed excellent pH sensitivity and obtained maximum swelling at pH 7. Besides that, hydrogel obtained showed significant increase in swelling ratio when temperature of swelling medium was increased from 25°C to 37°C. SEM micrograph showed that the pore size of the hydrogel decreases with increase of CNC content proving that the hydrogel structure became more rigid with addition of CNC. The PAA/CNC hydrogel with such excellent sensitivity towards pH and temperature can be developed further as drug carrier.« less

Dimethylarginine Dimethylaminohydrolase Overexpression enhances Insulin Sensitivity

PubMed Central

Sydow, Karsten; Mondon, Carl E.; Schrader, Joerg; Konishi, Hakuoh; Cooke, John P.

2011-01-01

Objective Previous studies suggest that nitric oxide (NO) may modulate insulin-induced uptake of glucose in insulin-sensitive tissues. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthase (NOS). We hypothesized that a reduction in endogenous ADMA would increase NO synthesis and thereby enhance insulin sensitivity. Methods and Results To test this hypothesis we employed a transgenic mouse in which we overexpressed human dimethylarginine dimethylaminohydrolase (DDAH-I). The DDAH-I mice had lower plasma ADMA at all ages (22–70 weeks) by comparison to wild-type (WT) littermates. With a glucose challenge, WT mice showed a prompt increase in ADMA, whereas DDAH-I mice had a blunted response. Furthermore, DDAH-I mice had a blunted increase in plasma insulin and glucose levels after glucose challenge, with a 50% reduction in the insulin resistence index, consistent with enhanced sensitivity to insulin. In liver, we observed an increased Akt phosphorylation in the DDAH-I mice after i.p. glucose challenge. Incubation of skeletal muscle from WT mice ex vivo with ADMA (2μM) markedly suppressed insulin-induced glycogen synthesis in fast-twitch but not slow-twitch muscle. Conclusions These findings suggest that the endogenous NOS inhibitor ADMA reduces insulin sensitivity, consistent with previous observations that NO plays a role in insulin sensitivity. PMID:18239148

GABAergic miniature postsynaptic currents in septal neurons show differential allosteric sensitivity after binge-like ethanol exposure.

PubMed

DuBois, Dustin W; Trzeciakowski, Jerome P; Parrish, Alan R; Frye, Gerald D

2006-05-17

Binge-like ethanol treatment of septal neurons blunts GABAAR-mediated miniature postsynaptic currents (mPSCs), suggesting it arrests synaptic development. Ethanol may disrupt postsynaptic maturation by blunting feedback signaling through immature GABAARs. Here, the impact of ethanol on the sensitivity of mPSCs to zolpidem, zinc and 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha-OH-DHP) was tested. The decay phase of mPSCs showed concentration-dependent potentiation by zolpidem (0.03-100 microM), which was substantially blunted after ethanol exposure. Since zolpidem potentiation exhibited a substantial age-dependent increase in untreated neurons, this finding supported the idea that ethanol arrests synaptic development. GABAAR alpha1 subunit protein also increased with age in untreated neurons, paralleling enhanced sensitivity to zolpidem. Surprisingly, alpha1 levels were not reduced by binge ethanol even though mPSCs were relatively zolpidem-insensitive. Zinc (3-30 microM) decreased mPSC parameters in a concentration- and age-related manner with older untreated cells showing less inhibition. However, there was no increase in mPSC zinc sensitivity after binge ethanol as would be expected if a general arrest of synaptic maturation had occurred. 3alpha-OH-DHP (3-1000 nM) induced concentration-dependent potentiation of mPSC decay. Although potentiation was age-independent, binge ethanol treatment exaggerated sensitivity to this neurosteroid. Finally, chronic picrotoxin pretreatment (100 microM) intended to mimic GABAAR inhibition from ethanol pretreatment did not significantly change mPSC modulation by zolpidem, zinc or 3alpha-OH-DHP. These results suggest that binge ethanol treatment selectively arrests a subset of processes important for maturation of postsynaptic GABAA Rs. However, it is unlikely that ethanol causes a broad arrest of postsynaptic development through a direct inhibition of GABAAR signaling.

Better Learning with More Error: Probabilistic Feedback Increases Sensitivity to Correlated Cues in Categorization

ERIC Educational Resources Information Center

Little, Daniel R.; Lewandowsky, Stephan

2009-01-01

Despite the fact that categories are often composed of correlated features, the evidence that people detect and use these correlations during intentional category learning has been overwhelmingly negative to date. Nonetheless, on other categorization tasks, such as feature prediction, people show evidence of correlational sensitivity. A…

Sensitivity in MALDI MS with small spot sizes

NASA Astrophysics Data System (ADS)

Yamchuk, Andriy

In MALDI, for laser fluences below the saturation point the ion yield per shot follows a cubic dependence on the irradiated area, leading to a conclusion that smaller spots produce overall less ions and therefore are less viable. However, Qiao et al. showed that by decreasing the laser spot size it is possible to raise the saturation point, and thus increase the ion yield per unit area, also known as sensitivity. Here we explore laser spots below 10 micrometer diameter to determine whether they offer any practical advantage. We show that sensitivity is greater for a flat-top 3--4 micrometer spot than for a 10 micrometer spot. The sensitivity is greater for a Gaussian-like 3--5 micrometer spot than for flat-top 5--25 micrometer spots. We also report for the first time sensitivity versus theoretical fluence profile for a Gaussian-like beam focu

Thermal design and verification of an instrument cooling system for infrared detectors utilizing the Oxford Stirling cycle refrigerator

NASA Technical Reports Server (NTRS)

Werrett, Stephen; Seivold, Alfred L.

1990-01-01

A detailed nodal computer model was developed to thermally represent the hardware, and sensitivity studies were performed to evaluate design parameters and orbital environmental effects of an instrument cooling system for IR detectors. Thermal-vacuum testing showed excellent performance of the system and a correspondence with math model predictions to within 3 K. Results show cold stage temperature sensitivity to cold patch backload, outer stage external surface emittance degradation, and cold stage emittance degradation, respectively. The increase in backload on the cold patch over the mission lifetime is anticipated to be less than 3.0 watts, which translates to less than a 3-degree increase in detector temperatures.

Design of a compact and high sensitive refractive index sensor base on metal-insulator-metal plasmonic Bragg grating.

PubMed

Binfeng, Yun; Guohua, Hu; Ruohu, Zhang; Yiping, Cui

2014-11-17

A nanometric and high sensitive refractive index sensor based on the metal-insulator-metal plasmonic Bragg grating is proposed. The wavelength encoded sensing characteristics of the refractive index sensor were investigated by analyzing its transmission spectrum. The numerical results show that a good linear relationship between the Bragg wavelength and the refractive index of the sensing material can be obtained, which is in accordance with the analytical results very well. A high refractive index sensitivity of 1,488 nm/RIU around Bragg resonance wavelength of 1,550 nm was obtained. Besides, the simulation results show that the sensitivity is depended on the Bragg resonance wavelength and the longer the Bragg resonance wavelength, the higher sensitivity can be obtained. Furthermore, the figure of merit of the refractive index sensor can be greatly increased by introducing a nano-cavity in the proposed plasmonic Bragg grating structure. This work pave the way for high sensitive nanometric refractive index sensor design and application.

Cutaneous sensitivity in unilateral trans-tibial amputees

PubMed Central

Templeton, Cale A.; Strzalkowski, Nicholas D. J.; Galvin, Patti

2018-01-01

Aim To examine tactile sensitivity in the leg and foot sole of below-knee amputees (diabetic n = 3, traumatic n = 1), and healthy control subjects (n = 4), and examine the association between sensation and balance. Method Vibration perception threshold (VPT; 3, 40, 250Hz) and monofilaments (MF) were used to examine vibration and light touch sensitivity on the intact limb, residual limb, and homologous locations on controls. A functional reach test was performed to assess functional balance. Results Tactile sensitivity was lower for diabetic amputee subjects compared to age matched controls for both VPT and MF; which was expected due to presence of diabetic peripheral neuropathy. In contrast, the traumatic amputee participant showed increased sensitivity for VPT at 40Hz and 250Hz vibration in both the intact and residual limbs compared to controls. Amputees with lower tactile sensitivity had shorter reach distances compared to those with higher sensitivity. Conclusion Changes in tactile sensitivity in the residual limb of trans-tibial amputees may have implications for the interaction between the amputee and the prosthetic device. The decreased skin sensitivity observed in the residual limb of subjects with diabetes is of concern as changes in skin sensitivity may be important in 1) identification/prevention of excessive pressure and 2) for functional stability. Interestingly, we saw increased residual limb skin sensitivity in the individual with the traumatic amputation. Although not measured directly in the present study, this increase in tactile sensitivity may be related to cortical reorganisation, which is known to occur following amputation, and would support similar findings observed in upper limb amputees. PMID:29856766

BIPOLAR DISORDER AND SUBSTANCE ABUSE: PATHOLOGICAL AND THERAPEUTIC IMPLICATIONS OF THEIR COMORBIDITY AND CROSS SENSITIZATION

PubMed Central

Post, Robert M.; Kalivas, Peter

2015-01-01

Background Bipolar disorder has a high co-occurrence with substance abuse disorders, but the pathophysiological mechanisms have not been adequately explored. Aims Review the role of stress in the onset and recurrence of affective episodes and substance abuse. Method We review the mechanisms involved in sensitization (increased responsivity) to recurrence of stressors, mood episodes, and cocaine use. Results Evidence suggests that intermittent stressors, mood episodes, and bouts of cocaine use not only show sensitization to themselves, but cross sensitization to the others contributing to illness progression. However, common mechanisms of sensitization, (such as regionally selective alterations in brain derived neurotrophic factor (BDNF) and hyperactivity of striatally-based habit memories), could also result in single therapies (such as N-acetylcysteine) having positive effects in all 3 domains. Conclusions These interacting sensitization processes suggest the importance of early intervention in attempting to prevent increasingly severe manifestations of bipolar illness and substance abuse progression. PMID:23457180

Increased BOLD Activation to Predator Stressor in Subiculum and Midbrain of Amphetamine-Sensitized Maternal Rats

PubMed Central

Febo, Marcelo; Pira, Ashley S.

2011-01-01

Amphetamine, which is known to cause sensitization, potentiates the hormonal and neurobiological signatures of stress and may also increase sensitivity to stress-inducing stimuli in limbic areas. Trimethylthiazoline (5 μL TMT) is a chemical constituent of fox feces that evokes innate fear and activates the neuronal and hormonal signatures of stress in rats. We used blood oxygen level dependent (BOLD) MRI to test whether amphetamine sensitization (1 mg/kg, i.p. X 3 days) in female rats has a lasting effect on the neural response to a stress-evoking stimulus, the scent of a predator, during the postpartum period. The subiculum and dopamine-enriched midbrain VTA/SN of amphetamine-sensitized, but not control mothers showed a greater BOLD signal response to predator odor than a control putrid scent. The greater responsiveness of these two brain regions following stimulant sensitization might impact neural processing in response to stressors in the maternal brain. PMID:21134359

Increased BOLD activation to predator stressor in subiculum and midbrain of amphetamine-sensitized maternal rats.

PubMed

Febo, Marcelo; Pira, Ashley S

2011-03-25

Amphetamine, which is known to cause sensitization, potentiates the hormonal and neurobiological signatures of stress and may also increase sensitivity to stress-inducing stimuli in limbic areas. Trimethylthiazoline (5μL TMT) is a chemical constituent of fox feces that evokes innate fear and activates the neuronal and hormonal signatures of stress in rats. We used blood oxygen level dependent (BOLD) MRI to test whether amphetamine sensitization (1mg/kg, i.p. ×3days) in female rats has a lasting effect on the neural response to a stress-evoking stimulus, the scent of a predator, during the postpartum period. The subiculum and dopamine-enriched midbrain VTA/SN of amphetamine-sensitized but not control mothers showed a greater BOLD signal response to predator odor than a control putrid scent. The greater responsiveness of these two brain regions following stimulant sensitization might impact neural processing in response to stressors in the maternal brain. Copyright © 2010 Elsevier B.V. All rights reserved.

Maternal Responsiveness and Sensitivity Re-Considered: Some Is More

PubMed Central

Bornstein, Marc H.; Manian, Nanmathi

2013-01-01

Is it always or necessarily the case that common and important parenting practices are better insofar as they occur more often, or worse because they occur less often? Perhaps, less is more, or some is more. To address this question, we studied mothers’ microcoded contingent responsiveness to their infants (M = 5.4 months, SD = 0.2) in relation to independent global judgments of the same mothers’ parenting sensitivity. In a community sample of 335 European American dyads, videorecorded infant and maternal behaviors were timed microanalytically throughout an extended home observation; separately and independently, global maternal sensitivity was rated macroanalytically. Sequential analysis and spline regression showed that, as maternal contingent responsiveness increased, judged maternal sensitivity increased to significance on the contingency continuum, after which mothers who were even more contingent were judged less sensitive. Just significant levels of maternal responsiveness are deemed optimally sensitive. Implications of these findings for typical and atypical parenting, child development, and intervention science are discussed. PMID:24229542

Influence of annealing on X-ray radiation sensing properties of TiO2 thin film

NASA Astrophysics Data System (ADS)

Sarma, M. P.; Kalita, J. M.; Wary, G.

2018-03-01

A recent study shows that the titanium dioxide (TiO2) thin film synthesised by a chemical bath deposition technique is a very useful material for the X-ray radiation sensor. In this work, we reported the influence of annealing on the X-ray radiation detection sensitivity of the TiO2 film. The films were annealed at 333 K, 363 K, 393 K, 473 K, and 573 K for 1 hour. Structural analyses showed that the microstrain and dislocation density decreased whereas the average crystallite size increased with annealing. The band gap of the films also decreased from 3.26 eV to 3.10 eV after annealing. The I-V characteristics record under the dark condition and under the X-ray irradiation showed that the conductivity increased with annealing. The influence of annealing on the detection sensitivity was negligible if the bias voltage applied across the films was low (within 0.2 V‒1.0 V). At higher bias voltage (>1.0 V), the contribution of electrons excited by X-ray became less significant which affected the detection sensitivity.

Effect of confinement in small space flight size cages on insulin sensitivity of exercise-trained rats

NASA Technical Reports Server (NTRS)

Mondon, C. E.; Dolkas, C. B.; Reaven, G. M.

1983-01-01

The effect of confinement in small cages (simulating the size to be used in future space Shuttle missions) on insulin sensitivity was studied in rats having an increased insulin sensitivity due to exercise training prior to confinement. Oral glucose tolerance tests (OGTT) were given to both control and exercise-trained rats before and after placement in the small cages for 7 days. The insulin resistance was assessed by the product of the area of the insulin and glucose curves of the OGTT (IG index). Results show that the values obtained before confinement were one-half as high in exercise-trained rats as those in control rats, reflecting an increased sensitivity to insulin with exercise training. After 7 days confinement, the IG index was found to be not significantly different from initial values for both control and exercise-trained rats. These findings suggest that increased insulin sensitivity in exercise-trained rats persists 7 days after cessation of running activity. The data also indicate that exercise training, before flight, may be beneficial in minimizing the loss of insulin sensitivity expected with decreased use of gravity dependent muscles during exposure to hypogravity in space flight.

Enhanced electrochemical sensitivity of enzyme precipitate coating (EPC)-based glucose oxidase biosensors with increased free CNT loadings.

PubMed

Kim, Jae Hyun; Jun, Sun-Ae; Kwon, Yongchai; Ha, Su; Sang, Byong-In; Kim, Jungbae

2015-02-01

Enzymatic electrodes were fabricated by using three different immobilizations of glucose oxidase (GOx): covalent enzyme attachment (CA), enzyme coating (EC), and enzyme precipitate coating (EPC), here referred to as CA-E, EC-E, and EPC-E, respectively. When additional carbon nanotubes (CNTs) were introduced from 0 to 75wt% for the EPC-E design, its initial biosensor sensitivity was improved from 2.40×10(-3) to 16.26×10(-3) A∙M(-1)∙cm(-2), while its electron charge transfer rate constant was increased from 0.33 to 1.47s(-1). When a fixed ratio of CNTs was added for three different electrode systems, EPC-E showed the best glucose sensitivity and long-term thermal stability. For example, when 75wt% of additional CNTs was added, the initial sensitivity of EPC-E was 16.26×10(-3) A∙M(-1)∙cm(-2), while those of EC-E and CA-E were only 6.42×10(-3) and 1.18×10(-3) A∙M(-1)∙cm(-2), respectively. Furthermore, EPC-E retained 63% of its initial sensitivity after thermal treatment at 40°C over 41days, while EC-E and CA-E showed only 12% and 1% of initial sensitivities, respectively. Consequently, the EPC approach with additional CNTs achieved both high sensitivity and long-term stability, which are required for continuous and accurate glucose monitoring. Copyright © 2014 Elsevier B.V. All rights reserved.

Variations in the temperature sensitivity of spring leaf phenology from 1978 to 2014 in Mudanjiang, China

NASA Astrophysics Data System (ADS)

Dai, Junhu; Xu, Yunjia; Wang, Huanjiong; Alatalo, Juha; Tao, Zexing; Ge, Quansheng

2017-12-01

Continuous long-term temperature sensitivity (ST) of leaf unfolding date (LUD) and main impacting factors in spring in the period 1978-2014 for 40 plant species in Mudanjiang, Heilongjiang Province, Northeast China, were analyzed by using observation data from the China Phenological Observation Network (CPON), together with the corresponding meteorological data from the China Meteorological Data Service Center. Temperature sensitivities, slopes of the regression between LUD and mean temperature during the optimum preseason (OP), were analyzed using 15-year moving window to determine their temporal trends. Major factors impacting ST were then chosen and evaluated by applying a random sampling method. The results showed that LUD was sensitive to mean temperature in a defined period before phenophase onset for all plant species analyzed. Over the period 1978-2014, the mean ST of LUD for all plant species was - 3.2 ± 0.49 days °C-1. The moving window analysis revealed that 75% of species displayed increasing ST of LUD, with 55% showing significant increases (P < 0.05). ST for the other 25% exhibited a decreasing trend, with 17% showing significant decreases (P < 0.05). On average, ST increased by 16%, from - 2.8 ± 0.83 days °C-1 during 1980-1994 to - 3.30 ± 0.65 days °C-1 during 2000-2014. For species with later LUD and longer OP, ST tended to increase more, while species with earlier LUD and shorter OP tended to display a decreasing ST. The standard deviation of preseason temperature impacted the temporal variation in ST. Chilling conditions influenced ST for some species, but photoperiod limitation did not have significant or coherent effects on changes in ST.

Van der Waals pressure sensors using reduced graphene oxide composites

NASA Astrophysics Data System (ADS)

Jung, Ju Ra; Ahn, Sung Il

2018-04-01

Reduced graphene oxide (RGO) films intercalated with various polymers were fabricated by reaction-based self-assembly, and their characteristics as vacuum pressure sensors based on van der Waals interactions were studied. At low temperature, the electrical resistances of the samples decrease linearly with increasing vacuum pressure, whereas at high temperature the variation of the electrical resistance shows secondary order curves. Among all samples, the poly vinyl alcohol intercalated RGO shows the highest sensitivity, being almost two times more sensitive than reference RGO. All samples show almost the same signal for repetitive sudden pressure changes, indicating reasonable reproducibility and durability.

Large area graphene ion sensitive field effect transistors with tantalum pentoxide sensing layers for pH measurement at the Nernstian limit

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

Fakih, Ibrahim, E-mail: ibrahim.fakih@mail.mcgill.ca; Sabri, Shadi; Szkopek, Thomas, E-mail: thomas.szkopek@mcgill.ca

2014-08-25

We have fabricated and characterized large area graphene ion sensitive field effect transistors (ISFETs) with tantalum pentoxide sensing layers and demonstrated pH sensitivities approaching the Nernstian limit. Low temperature atomic layer deposition was used to deposit tantalum pentoxide atop large area graphene ISFETs. The charge neutrality point of graphene, inferred from quantum capacitance or channel conductance, was used to monitor surface potential in the presence of an electrolyte with varying pH. Bare graphene ISFETs exhibit negligible response, while graphene ISFETs with tantalum pentoxide sensing layers show increased sensitivity reaching up to 55 mV/pH over pH 3 through pH 8. Applying themore » Bergveld model, which accounts for site binding and a Guoy-Chapman-Stern picture of the surface-electrolyte interface, the increased pH sensitivity can be attributed to an increased buffer capacity reaching up to 10{sup 14} sites/cm{sup 2}. ISFET response was found to be stable to better than 0.05 pH units over the course of two weeks.« less

Large area graphene ion sensitive field effect transistors with tantalum pentoxide sensing layers for pH measurement at the Nernstian limit

NASA Astrophysics Data System (ADS)

Fakih, Ibrahim; Sabri, Shadi; Mahvash, Farzaneh; Nannini, Matthieu; Siaj, Mohamed; Szkopek, Thomas

2014-08-01

We have fabricated and characterized large area graphene ion sensitive field effect transistors (ISFETs) with tantalum pentoxide sensing layers and demonstrated pH sensitivities approaching the Nernstian limit. Low temperature atomic layer deposition was used to deposit tantalum pentoxide atop large area graphene ISFETs. The charge neutrality point of graphene, inferred from quantum capacitance or channel conductance, was used to monitor surface potential in the presence of an electrolyte with varying pH. Bare graphene ISFETs exhibit negligible response, while graphene ISFETs with tantalum pentoxide sensing layers show increased sensitivity reaching up to 55 mV/pH over pH 3 through pH 8. Applying the Bergveld model, which accounts for site binding and a Guoy-Chapman-Stern picture of the surface-electrolyte interface, the increased pH sensitivity can be attributed to an increased buffer capacity reaching up to 1014 sites/cm2. ISFET response was found to be stable to better than 0.05 pH units over the course of two weeks.

Study on hot melt pressure sensitive coil material for removing surface nuclear pollution dust

NASA Astrophysics Data System (ADS)

Wang, Jing; Li, Jiao; Wang, Jianhui; Zheng, Li; Li, Jian; Lv, Linmei

2018-02-01

A new method for removing surface nuclear pollution by using hot melt pressure sensitive membrane was presented. The hot melt pressure sensitive membrane was designed and prepared by screening hot melt pressure sensitive adhesive and substrate. The simulated decontamination test of the hot melt pressure sensitive membrane was performed by using 100 mesh and 20 mesh standard sieve dust for simulation of nuclear explosion fall ash and radioactive contaminated particles, respectively. It was found that the single decontamination rate of simulated fall ash and contaminated particles were both above 80% under pressure conditions of 25kPa or more at 140°C. And the maximum single decontamination rate was 92.5%. The influence of heating temperature and pressure on the decontamination rate of the membrane was investigated at the same time. The results showed that higher heating temperature could increase the decontamination rate by increasing the viscosity of the adhesive. When the adhesive amount of the adhesive layer reached saturation, a higher pressure could increase the single decontamination rate also.

Size determines antennal sensitivity and behavioral threshold to odors in bumblebee workers

NASA Astrophysics Data System (ADS)

Spaethe, Johannes; Brockmann, Axel; Halbig, Christine; Tautz, Jürgen

2007-09-01

The eusocial bumblebees exhibit pronounced size variation among workers of the same colony. Differently sized workers engage in different tasks (alloethism); large individuals are found to have a higher probability to leave the colony and search for food, whereas small workers tend to stay inside the nest and attend to nest duties. We investigated the effect of size variation on morphology and physiology of the peripheral olfactory system and the behavioral response thresholds to odors in workers of Bombus terrestris. Number and density of olfactory sensilla on the antennae correlate significantly with worker size. Consistent with these morphological changes, we found that antennal sensitivity to odors increases with body size. Antennae of large individuals show higher electroantennogram responses to a given odor concentration than those of smaller nestmates. This finding indicates that large antennae exhibit an increased capability to catch odor molecules and thus are more sensitive to odors than small antennae. We confirmed this prediction in a dual choice behavioral experiment showing that large workers indeed are able to respond correctly to much lower odor concentrations than small workers. Learning performance in these experiments did not differ between small and large bumblebees. Our results clearly show that, in the social bumblebees, variation in olfactory sensilla number due to size differences among workers strongly affects individual odor sensitivity. We speculate that superior odor sensitivity of large workers has favored size-related division of labor in bumblebee colonies.

Spermine modulates the expression of two probable polyamine transporter genes and determines growth responses to cadaverine in Arabidopsis.

PubMed

Sagor, G H M; Berberich, Thomas; Kojima, Seiji; Niitsu, Masaru; Kusano, Tomonobu

2016-06-01

Two genes, LAT1 and OCT1 , are likely to be involved in polyamine transport in Arabidopsis. Endogenous spermine levels modulate their expression and determine the sensitivity to cadaverine. Arabidopsis spermine (Spm) synthase (SPMS) gene-deficient mutant was previously shown to be rather resistant to the diamine cadaverine (Cad). Furthermore, a mutant deficient in polyamine oxidase 4 gene, accumulating about twofold more of Spm than wild type plants, showed increased sensitivity to Cad. It suggests that endogenous Spm content determines growth responses to Cad in Arabidopsis thaliana. Here, we showed that Arabidopsis seedlings pretreated with Spm absorbs more Cad and has shorter root growth, and that the transgenic Arabidopsis plants overexpressing the SPMS gene are hypersensitive to Cad, further supporting the above idea. The transgenic Arabidopsis overexpressing L-Amino acid Transporter 1 (LAT1) absorbed more Cad and showed increased Cad sensitivity, suggesting that LAT1 functions as a Cad importer. Recently, other research group reported that Organic Cation Transporter 1 (OCT1) is a causal gene which determines the Cad sensitivity of various Arabidopsis accessions. Furthermore, their results suggested that OCT1 is involved in Cad efflux. Thus we monitored the expression of OCT1 and LAT1 during the above experiments. Based on the results, we proposed a model in which the level of Spm content modulates the expression of OCT1 and LAT1, and determines Cad sensitivity of Arabidopsis.

Identification of photoactivated adenylyl cyclases in Naegleria australiensis and BLUF-containing protein in Naegleria fowleri.

PubMed

Yasukawa, Hiro; Sato, Aya; Kita, Ayaka; Kodaira, Ken-Ichi; Iseki, Mineo; Takahashi, Tetsuo; Shibusawa, Mami; Watanabe, Masakatsu; Yagita, Kenji

2013-01-01

Complete genome sequencing of Naegleria gruberi has revealed that the organism encodes polypeptides similar to photoactivated adenylyl cyclases (PACs). Screening in the N. australiensis genome showed that the organism also encodes polypeptides similar to PACs. Each of the Naegleria proteins consists of a "sensors of blue-light using FAD" domain (BLUF domain) and an adenylyl cyclase domain (AC domain). PAC activity of the Naegleria proteins was assayed by comparing sensitivities of Escherichia coli cells heterologously expressing the proteins to antibiotics in a dark condition and a blue light-irradiated condition. Antibiotics used in the assays were fosfomycin and fosmidomycin. E. coli cells expressing the Naegleria proteins showed increased fosfomycin sensitivity and fosmidomycin sensitivity when incubated under blue light, indicating that the proteins functioned as PACs in the bacterial cells. Analysis of the N. fowleri genome revealed that the organism encodes a protein bearing an amino acid sequence similar to that of BLUF. A plasmid expressing a chimeric protein consisting of the BLUF-like sequence found in N. fowleri and the adenylyl cyclase domain of N. gruberi PAC was constructed to determine whether the BLUF-like sequence functioned as a sensor of blue light. E. coli cells expressing a chimeric protein showed increased fosfomycin sensitivity and fosmidomycin sensitivity when incubated under blue light. These experimental results indicated that the sequence similar to the BLUF domain found in N. fowleri functioned as a sensor of blue light.

Enhanced biosensing resolution with foundry fabricated individually addressable dual-gated ISFETs.

PubMed

Duarte-Guevara, Carlos; Lai, Fei-Lung; Cheng, Chun-Wen; Reddy, Bobby; Salm, Eric; Swaminathan, Vikhram; Tsui, Ying-Kit; Tuan, Hsiao Chin; Kalnitsky, Alex; Liu, Yi-Shao; Bashir, Rashid

2014-08-19

The adaptation of semiconductor technologies for biological applications may lead to a new era of inexpensive, sensitive, and portable diagnostics. At the core of these developing technologies is the ion-sensitive field-effect transistor (ISFET), a biochemical to electrical transducer with seamless integration to electronic systems. We present a novel structure for a true dual-gated ISFET that is fabricated with a silicon-on-insulator (SOI) complementary metal-oxide-semiconductor process by Taiwan Semiconductor Manufacturing Company (TSMC). In contrast to conventional SOI ISFETs, each transistor has an individually addressable back-gate and a gate oxide that is directly exposed to the solution. The elimination of the commonly used floating gate architecture reduces the chance of electrostatic discharge and increases the potential achievable transistor density. We show that when operated in a "dual-gate" mode, the transistor response can exhibit sensitivities to pH changes beyond the Nernst limit. This enhancement in sensitivity was shown to increase the sensor's signal-to-noise ratio, allowing the device to resolve smaller pH changes. An improved resolution can be used to enhance small signals and increase the sensor accuracy when monitoring small pH dynamics in biological reactions. As a proof of concept, we demonstrate that the amplified sensitivity and improved resolution result in a shorter detection time and a larger output signal of a loop-mediated isothermal DNA amplification reaction (LAMP) targeting a pathogenic bacteria gene, showing benefits of the new structure for biosensing applications.

Sub-grid scale precipitation in ALCMs: re-assessing the land surface sensitivity using a single column model

NASA Astrophysics Data System (ADS)

Pitman, Andrew J.; Yang, Zong-Liang; Henderson-Sellers, Ann

1993-10-01

The sensitivity of a land surface scheme to the distribution of precipitation within a general circulation model's grid element is investigated. Earlier experiments which showed considerable sensitivity of the runoff and evaporation simulation to the distribution of precipitation are repeated in the light of other results which show no sensitivity of evaporation to the distribution of precipitation. Results show that while the earlier results over-estimated the sensitivity of the surface hydrology to the precipitation distribution, the general conclusion that the system is sensitive is supported. It is found that changing the distribution of precipitation from falling over 100% of the grid square to falling over 10% leads to a reduction in evaporation from 1578 mm y-1 to 1195 mm y -1 while runoff increases from 278 mm y-1 to 602 mm y-1. The sensitivity is explained in terms of evaporation being dominated by available energy when precipitation falls over nearly the entire grid square, but by moisture availability (mainly intercepted water) when it falls over little of the grid square. These results also indicate that earlier work using stand-alone forcing to drive land surface schemes ‘off-line’, and to investigate the sensitivity of land surface codes to various parameters, leads to results which are non-repeatable in single column simulations.

Why Your Mother Was Right: How Potassium Intake Reduces Blood Pressure.

PubMed

Ellison, David H; Terker, Andrew S

2015-01-01

Low potassium intake, common in western diets, increases blood pressure and enhances salt-sensitivity. Most humans in "Westernized" countries also consume excess salt. In studies using mice, we found that a high-salt, low-potassium diet activates the thiazide-sensitive Na-Cl cotransporter in the kidney. This effect led to sodium retention and increased blood pressure, and was dependent on plasma potassium. We postulated that this effect was mediated by changes in intracellular chloride caused by changes in membrane voltage. We developed a model in cultured cells permitting us to confirm this hypothesis. We then confirmed, using urinary exosomes, that dietary changes in normal humans, affect the thiazide-sensitive Na-Cl cotransporter in the same way. These data show that dietary potassium deficiency increases blood pressure largely by stimulating salt reabsorption along the distal nephron. They suggest that global efforts should focus on increasing potassium intake, which will attenuate the effects of high-salt diets.

Sensitivity of resonant tunneling diode photodetectors.

PubMed

Pfenning, Andreas; Hartmann, Fabian; Langer, Fabian; Kamp, Martin; Höfling, Sven; Worschech, Lukas

2016-09-02

We have studied the sensitivity of AlGaAs/GaAs double barrier resonant tunneling diode photodetectors with an integrated GaInNAs absorption layer for light sensing at the telecommunication wavelength of λ = 1.3 μm for illumination powers from pico- to microwatts. The sensitivity decreases nonlinearly with power. An illumination power increase of seven orders of magnitude leads to a reduction of the photocurrent sensitivity from S I  = 5.82 × 10(3) A W(-1) to 3.2 A W(-1). We attribute the nonlinear sensitivity-power dependence to an altered local electrostatic potential due to hole-accumulation that on the one hand tunes the tunneling current, but on the other hand affects the lifetime of photogenerated holes. In particular, the lifetime decreases exponentially with increasing hole population. The lifetime reduction results from an enhanced electrical field, a rise of the quasi-Fermi level, and an increased energy splitting within the triangular potential well. The non-constant sensitivity is a direct result of the non-constant lifetime. Based on these findings, we provide an expression that allows us to calculate the sensitivity as a function of illumination power and bias voltage, show a way to model the time-resolved photocurrent, and determine the critical power up to which the resonant tunneling diode photodetector sensitivity can be assumed constant.

The impact of serum incubation time on IgM/IgG binding to porcine aortic endothelial cells.

PubMed

Zhang, Zhongqiang; Gao, Bingsi; Zhao, Chengjiang; Long, Cassandra; Qi, Haizhi; Ezzelarab, Mohamed; Cooper, David Kc; Hara, Hidetaka

2017-07-01

The results of the assay for measuring anti-non-Gal antibodies (which affect pig xenograft survival) in recipients are important. Serum incubation time and concentration may be important factors in the extent of antibody binding to the graft. The aim of this in vitro study was to determine the optimal incubation time and serum concentration for measuring anti-non-Gal antibody binding to porcine aortic endothelial cells (pAECs). Pooled human, naive, and sensitized baboon sera were incubated with wild-type, α1,3-galactosyltransferase gene-knockout (GTKO), and GTKO/human CD55 pAECs. IgM/IgG binding to pAECs after varying serum incubation times (0.5, 1, 2, and 3 hour) and concentrations (5, 10, 20, and 40 μL) was determined by flow cytometry. An increase in incubation time from 30 minutes to 2 hour was associated with increases in anti-non-Gal IgM/IgG binding to GTKO and GTKO/hCD55 pAECs of pooled human, naive and sensitized baboon sera (P<.05). Pooled human serum showed a significant increase in anti-non-Gal IgM (1.5 times) and a minimal increase in anti-non-Gal IgG antibody binding. IgM/IgG binding of sensitized baboon serum to GTKO pAECs after 2-hour incubation was 1.5 times and 2 times greater than after 30-minutes incubation, respectively, whereas naïve baboon sera showed minimal (non-significant) increase in anti-non-Gal IgM/IgG antibody binding. With 2-hour incubation, increasing the serum concentration from 5 μL to 20 μL significantly increased antibody binding to non-Gal antigens in pooled human and sensitized baboon serum. With naïve baboon serum, only IgG was significantly increased. Increasing the serum incubation time contributed to improve the sensitivity of detecting anti-non-Gal antibodies, without affecting cell viability in vitro. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Chronic tolerance to ethanol-induced sedation: implication for age-related differences in locomotor sensitization.

PubMed

Quoilin, Caroline; Didone, Vincent; Tirelli, Ezio; Quertemont, Etienne

2013-06-01

The adolescent brain has been suggested to be particularly sensitive to ethanol-induced neuroadaptations, which in turn could increase the risk of youths for alcohol abuse and dependence. Sensitization to the locomotor stimulant effects of ethanol has often been used as an animal model of ethanol-induced neuroadaptations. Previously, we showed that young mice were more sensitive than adults to the locomotor sensitization induced by high ethanol doses. However, this effect could be due to age-related differences in chronic tolerance to the sedative effects of ethanol. The aim of the present study is to assess chronic tolerance to the sedative effects of ethanol in weaning 21-day-old (P21), adolescent 35-day-old (P35) and adult 63-day-old (P63) female Swiss mice. After a daily injection of saline or 4 g/kg ethanol during 6 consecutive days, all P21, P35 and P63 mice were injected with 4 g/kg ethanol and submitted to the loss of righting reflex procedure. Our results confirm that the sensitivity to the acute sedative effects of ethanol gradually increases with age. Although this schedule of ethanol injections induces significant age-related differences in ethanol sensitization, it did not reveal significant differences between P21, P35 and P63 mice in the development of a chronic ethanol tolerance to its sedative effects. The present results show that age-related differences in the development of ethanol sensitization cannot be explained by differences in chronic ethanol tolerance to its sedative effects. More broadly, they do not support the idea that ethanol-induced sensitization is a by-product of chronic ethanol tolerance. Copyright © 2013 Elsevier Inc. All rights reserved.

Sensitivity of allowable cuts to intensive management.

Treesearch

Roger D. Fight; Dennis L. Schweitzer

1974-01-01

A sensitivity analysis of allowable cuts on two BLM master units shows that even-flow allowable cuts depend primarily on: (1) assumed long-term growth potential, (2) period that growth increases must be cumulated before they can be removed from the stands on which they occur, and (3) amount and age-class distribution of the initial inventory. Current allowable cut...

Effects of Various Fillet Shapes on a 76/40 Double Delta Wing from Mach 0.18 to 0.7

NASA Technical Reports Server (NTRS)

Erickson, Gary E.; Bell, James H.; Gonzalez, Hugo A.; McLachlan, Blair G.

2003-01-01

The effects of linear, diamond, and parabolic fillets on a double delta wing were investigated in the NASA Langley 7 x 10 ft High Speed Tunnel from Mach 0.18 to 0.7 and angles of attack from 4 deg. to 42 deg. Force and moment, pneumatic pressures, pressure sensitive paint, and vapor screen flow visualization measurements were used to characterize the flow field and to determine longitudinal forces and moments. The fillets increased lift coefficient and reduced induced drag without significantly affecting pitching moment. Pressure sensitive paint showed the increase in lift is caused by an increase in suction and broadening of the vortex suction footprint. Vapor screen results showed the mixing and coalescing of the strake fillet and wing vortices causes the footprint to broaden.

Extending the Administration Time of the Letter Fluency Test Increases Sensitivity to Cognitive Status in Aging

PubMed Central

Holtzer, R.; Goldin, Y.; Donovick, P.J.

2010-01-01

We examined whether extending the administration time of letter fluency from one minute per letter trial (standard administration) to two minutes increased the sensitivity of this test to cognitive status in aging. Participants (mean age = 84.6) were assigned to cognitive impairment (n=20) and control (n=40) groups. Pearson correlations and scatter plot analyses showed that associations between the Dementia Rating Scale scores and letter fluency were higher and less variable when performance on the latter was extended to two minutes. ANOVA showed that the cognitive impairment group generated fewer words in the second minute of the letter fluency task compared to the control group. Finally, discriminant function analyses revealed that extending the letter fluency trials to two minutes increased discrimination between the control and cognitive impairment groups. PMID:19449244

Sickle cell mice exhibit mechanical allodynia and enhanced responsiveness in light touch cutaneous mechanoreceptors

PubMed Central

2012-01-01

Background Sickle cell disease (SCD) is associated with both acute vaso-occlusive painful events as well as chronic pain syndromes, including heightened sensitivity to touch. We have previously shown that mice with severe SCD (HbSS mice; express 100% human sickle hemoglobin in red blood cells; RBCs) have sensitized nociceptors, which contribute to increased mechanical sensitivity. Yet, the hypersensitivity in these neural populations alone may not fully explain the mechanical allodynia phenotype in mouse and humans. Findings Using the Light Touch Behavioral Assay, we found HbSS mice exhibited increased responses to repeated application of both innocuous punctate and dynamic force compared to control HbAA mice (100% normal human hemoglobin). HbSS mice exhibited a 2-fold increase in percent response to a 0.7mN von Frey monofilament when compared to control HbAA mice. Moreover, HbSS mice exhibited a 1.7-fold increase in percent response to the dynamic light touch “puffed” cotton swab stimulus. We further investigated the mechanisms that drive this behavioral phenotype by focusing on the cutaneous sensory neurons that primarily transduce innocuous, light touch. Low threshold cutaneous afferents from HbSS mice exhibited sensitization to mechanical stimuli that manifested as an increase in the number of evoked action potentials to suprathreshold force. Rapidly adapting (RA) Aβ and Aδ D-hair fibers showed the greatest sensitization, each with a 75% increase in suprathreshold firing compared to controls. Slowly adapting (SA) Aβ afferents had a 25% increase in suprathreshold firing compared to HbAA controls. Conclusions These novel findings demonstrate mice with severe SCD exhibit mechanical allodynia to both punctate and dynamic light touch and suggest that this behavioral phenotype may be mediated in part by the sensitization of light touch cutaneous afferent fibers to suprathreshold force. These findings indicate that Aβ fibers can be sensitized to mechanical force and should potentially be examined for sensitization in other tissue injury and disease models. PMID:22963123

Psychological Stress Induces Temporary Masticatory Muscle Mechanical Sensitivity in Rats

PubMed Central

Huang, Fei; Zhang, Min; Chen, Yong-Jin; Li, Qiang; Wu, An-Zhen

2011-01-01

To explore the relationship between psychological stress and masticatory muscle pain, we created a communication stress animal model to determine whether psychological stress could induce increased mechanical sensitivity in masticatory muscles and to study the changes of mechanical nociceptive thresholds after stress removal. Forty-eight male Sprague-Dawley rats were divided into a control group (CON), a foot-shocked group (FS, including 3 subgroups recorded as FS-1, FS-2, and FS-3), a psychological stress group (PS), and a drug treatment group (DT). PS and DT rats were confined in a communication box for one hour a day to observe the psychological responses of neighboring FS rats.Measurements of the mechanical nociceptive thresholds of the bilateral temporal and masseter muscles showed a stimulus-response relationship between psychological stress and muscle mechanical sensitivity. The DT rats, who received a diazepam injection, showed almost the same mechanical sensitivity of the masticatory muscles to that of the control in response to psychological stress. Fourteen days after the psychological stressor was removed, the mechanical nociceptive thresholds returned to normal. These findings suggest that psychological stress is directly related to masticatory muscle pain. Removal of the stressor could be a useful method for relieving mechanical sensitivity increase induced by psychological stress. PMID:21331360

Optical bio-chemical sensors on SNOW ring resonators.

PubMed

Khorasaninejad, Mohammadreza; Clarke, Nigel; Anantram, M P; Saini, Simarjeet Singh

2011-08-29

In this paper, we propose and analyze novel ring resonator based bio-chemical sensors on silicon nanowire optical waveguide (SNOW) and show that the sensitivity of the sensors can be increased by an order of magnitude as compared to silicon-on-insulator based ring resonators while maintaining high index contrast and compact devices. The core of the waveguide is hollow and allows for introduction of biomaterial in the center of the mode, thereby increasing the sensitivity of detection. A sensitivity of 243 nm/refractive index unit (RIU) is achieved for a change in bulk refractive index. For surface attachment, the sensor is able to detect monolayer attachments as small as 1 Å on the surface of the silicon nanowires.

Optical bio-chemical sensors on SNOW ring resonators

NASA Astrophysics Data System (ADS)

Khorasaninejad, Mohammadreza; Clarke, Nigel; Anantram, M. P.; Singh Saini, Simarjeet

2011-08-01

In this paper, we propose and analyze novel ring resonator based bio-chemical sensors on silicon nanowire optical waveguide (SNOW) and show that the sensitivity of the sensors can be increased by an order of magnitude as compared to silicon-on-insulator based ring resonators while maintaining high index contrast and compact devices. The core of the waveguide is hollow and allows for introduction of biomaterial in the center of the mode, thereby increasing the sensitivity of detection. A sensitivity of 243 nm/refractive index unit (RIU) is achieved for a change in bulk refractive index. For surface attachment, the sensor is able to detect monolayer attachments as small as 1 Å on the surface of the silicon nanowires.

Porous PZT ceramics for receiving transducers.

PubMed

Kara, Hudai; Ramesh, Rajamani; Stevens, Ron; Bowen, Chris R

2003-03-01

PZT-air (porous PZT) and PZT-polymer (polymer impregnated porous PZT) piezocomposites with varying porosity/polymer volume fractions have been manufactured. The composites were characterized in terms of hydrostatic charge (dh) and voltage (gh) coefficients, permittivity, hydrostatic figure of merit (dh.gh), and absolute sensitivity (M). With decreasing PZT ceramic volume, gh increased, and dh.gh had a broad maximum around 80 to 90% porosity/polymer content. The absolute sensitivity was also increased. In each case, PZT-air piezocomposites performed better than PZT-polymer piezocomposites. Hydrophones constructed from piezocomposites showed slightly lower measured receiving sensitivities than calculated values for piezocomposite materials, which was due to the loading effect of the cable and the low permittivity associated with the piezocomposites.

Counting Molecules by Desorption Ionization and Mass Spectrometry/Mass Spectrometry.

ERIC Educational Resources Information Center

Cooks, R. G.; Busch, K. L.

1982-01-01

Discusses two newer methods in mass spectrometry and shows how they can increase signal and signal-to-noise ratios, respectively. The first method, desorption ionization (DI), increases sensitivity while the second method, mass spectrometry/mass spectrometry (MS/MS), increases specificity. Together, the two methods offer improved analytical…

Visual reliability and information rate in the retina of a nocturnal bee.

PubMed

Frederiksen, Rikard; Wcislo, William T; Warrant, Eric J

2008-03-11

Nocturnal animals relying on vision typically have eyes that are optically and morphologically adapted for both increased sensitivity and greater information capacity in dim light. Here, we investigate whether adaptations for increased sensitivity also are found in their photoreceptors by using closely related and fast-flying nocturnal and diurnal bees as model animals. The nocturnal bee Megalopta genalis is capable of foraging and homing by using visually discriminated landmarks at starlight intensities. Megalopta's near relative, Lasioglossum leucozonium, performs these tasks only in bright sunshine. By recording intracellular responses to Gaussian white-noise stimuli, we show that photoreceptors in Megalopta actually code less information at most light levels than those in Lasioglossum. However, as in several other nocturnal arthropods, Megalopta's photoreceptors possess a much greater gain of transduction, indicating that nocturnal photoreceptors trade information capacity for sensitivity. By sacrificing photoreceptor signal-to-noise ratio and information capacity in dim light for an increased gain and, thus, an increased sensitivity, this strategy can benefit nocturnal insects that use neural summation to improve visual reliability at night.

The strain-rate sensitivity of high-strength high-toughness steels.

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

Dilmore, M.F.; Crenshaw, Thomas B.; Boyce, Brad Lee

2006-01-01

The present study examines the strain-rate sensitivity of four high strength, high-toughness alloys at strain rates ranging from 0.0002 s-1 to 200 s-1: Aermet 100, a modified 4340, modified HP9-4-20, and a recently developed Eglin AFB steel alloy, ES-1c. A refined dynamic servohydraulic method was used to perform tensile tests over this entire range. Each of these alloys exhibit only modest strain-rate sensitivity. Specifically, the strain-rate sensitivity exponent m, is found to be in the range of 0.004-0.007 depending on the alloy. This corresponds to a {approx}10% increase in the yield strength over the 7-orders of magnitude change in strain-rate.more » Interestingly, while three of the alloys showed a concominant {approx}3-10% drop in their ductility with increasing strain-rate, the ES1-c alloy actually exhibited a 25% increase in ductility with increasing strain-rate. Fractography suggests the possibility that at higher strain-rates ES-1c evolves towards a more ductile dimple fracture mode associated with microvoid coalescence.« less

Experimental study on the influence of slickwater on shale permeability

NASA Astrophysics Data System (ADS)

Liu, Zhonghua; Bai, Baojun; Zhang, Zheyu; Tang, Jing; Zeng, Shunpeng; Li, Xiaogang

2018-02-01

There are two diametrically opposite views of the influence of slickwater on shale permeability among scholars at home and abroad. We used the shale outcrops rock samples from the Lower Silurian Longmaxi Formation in Sichuan Basin. The permeability of these dry samples before and after immersion in different solution systems were tested by pulse attenuation method. The experimental results show that the impregnation of different slickwater components and standard salt solution can promote the increase of the permeability of shale samples. The stress sensitivity of shale samples after liquid immersion is medium weak to weak. The sample stress sensitivity is weak after soaked by the synergist solution and Drag reducing agent solution, and the sensitivity of the sample stress is medium weak after immersed by the standard saline solution, defoamer solution and antiswelling solution; The Ki/K0 of the shale sample after liquid immersion on σi/σ0 is consistent with the exponential stress sensitive evaluation model. With the increase of soaking time, the increase of sample permeability increases first and then decreases.

Determination of ABO blood grouping and Rhesus factor from tooth material.

PubMed

Kumar, Pooja Vijay; Vanishree, M; Anila, K; Hunasgi, Santosh; Suryadevra, Sri Sujan; Kardalkar, Swetha

2016-01-01

The aim of the study was to determine blood groups and Rhesus factor from dentin and pulp using absorption-elution (AE) technique in different time periods at 0, 3, 6, 9 and 12 months, respectively. A total of 150 cases, 30 patients each at 0, 3, 6, 9 and 12 months were included in the study. The samples consisted of males and females with age ranging 13-60 years. Patient's blood group was checked and was considered as "control." The dentin and pulp of extracted teeth were tested for the presence of ABO/Rh antigen, at respective time periods by AE technique. Data were analyzed in proportion. For comparison, Chi-square test or Fisher's exact test was used for the small sample. Blood group antigens of ABO and Rh factor were detected in dentin and pulp up to 12 months. For both ABO and Rh factor, dentin and pulp showed 100% sensitivity for the samples tested at 0 month and showed a gradual decrease in the sensitivity as time period increased. The sensitivity of pulp was better than dentin for both the blood grouping systems and ABO blood group antigens were better detected than Rh antigens. In dentin and pulp, the antigens of ABO and Rh factor were detected up to 12 months but showed a progressive decrease in the antigenicity as the time period increased. When compared the results obtained of dentin and pulp in ABO and Rh factor grouping showed similar results with no statistical significance. The sensitivity of ABO blood grouping was better than Rh factor blood grouping and showed a statistically significant result.

Dynamic Equilibrium of Cardiac Troponin C's Hydrophobic Cleft and Its Modulation by Ca2+ Sensitizers and a Ca2+ Sensitivity Blunting Phosphomimic, cTnT(T204E).

PubMed

Schlecht, William; Dong, Wen-Ji

2017-10-18

Several studies have suggested that conformational dynamics are important in the regulation of thin filament activation in cardiac troponin C (cTnC); however, little direct evidence has been offered to support these claims. In this study, a dye homodimerization approach is developed and implemented that allows the determination of the dynamic equilibrium between open and closed conformations in cTnC's hydrophobic cleft. Modulation of this equilibrium by Ca 2+ , cardiac troponin I (cTnI), cardiac troponin T (cTnT), Ca 2+ -sensitizers, and a Ca 2+ -desensitizing phosphomimic of cTnT (cTnT(T204E) is characterized. Isolated cTnC contained a small open conformation population in the absence of Ca 2+ that increased significantly upon the addition of saturating levels of Ca 2+ . This suggests that the Ca 2+ -induced activation of thin filament arises from an increase in the probability of hydrophobic cleft opening. The inclusion of cTnI increased the population of open cTnC, and the inclusion of cTnT had the opposite effect. Samples containing Ca 2+ -desensitizing cTnT(T204E) showed a slight but insignificant decrease in open conformation probability compared to samples with cardiac troponin T, wild type [cTnT(wt)], while Ca 2+ sensitizer treated samples generally increased open conformation probability. These findings show that an equilibrium between the open and closed conformations of cTnC's hydrophobic cleft play a significant role in tuning the Ca 2+ sensitivity of the heart.

Pain Sensitivity and Recovery From Mild Chronic Sleep Loss

PubMed Central

Roehrs, Timothy A.; Harris, Erica; Randall, Surilla; Roth, Thomas

2012-01-01

Study Objectives: To determine whether an extended bedtime in sleepy and otherwise healthy volunteers would increase alertness and thereby also reduce pain sensitivity. Setting: Outpatient with sleep laboratory assessments. Participants and Interventions: Healthy volunteers (n = 18), defined as having an average daily sleep latency on the Multiple Sleep Latency Test (MSLT) < 8 min, were randomized to 4 nights of extended bedtime (10 hr) (EXT) or 4 nights of their diary-reported habitual bedtimes (HAB). On day 1 and day 4 they received a standard MSLT (10:00, 12:00, 14:00, and 16:00 hr) and finger withdrawal latency pain testing to a radiant heat stimulus (10:30 and 14:30 hr). Results: During the four experimental nights the EXT group slept 1.8 hr per night more than the HAB group and average daily sleep latency on the MSLT increased in the EXT group, but not the HAB group. Similarly, finger withdrawal latency was increased (pain sensitivity was reduced) in the EXT group but not the HAB group. The nightly increase in sleep time during the four experimental nights was correlated with the improvement in MSLT, which in turn was correlated with reduced pain sensitivity. Conclusions: These are the first data to show that an extended bedtime in mildly sleepy healthy adults, which resulted in increased sleep time and reduced sleepiness, reduces pain sensitivity. Citation: Roehrs TA; Harris E; Randall S; Roth T. Pain sensitivity and recovery from mild chronic sleep loss. SLEEP 2012;35(12):1667-1672. PMID:23204609

Dopaminergic Reward Sensitivity Can Promote Adolescent Health: A New Perspective on the Mechanism of Ventral Striatum Activation

PubMed Central

Telzer, Eva H.

2015-01-01

The prevailing view in the field of adolescent brain development is that heightened activity in the mesolimbic dopaminergic reward system serves as a liability, orienting adolescents towards risky behaviors, increasing their sensitivity to social evaluation and loss, and resulting in compromised well-being. Several findings inconsistent with this deficit view challenge the perspective that adolescent reward sensitivity largely serves as a liability and highlights the potential adaptive function that heightened striatal reactivity can serve. The goal of this review is to refine our understanding of dopaminergic reward sensitivity in adolescence. I review several studies showing that ventral striatum activation serves an adaptive function for adolescents’ health and well being relating to declines in both risk taking and depression and increases in cognitive persistence and achievement. PMID:26708774

Time-dependent edge notch sensitivity of Inconel 718 sheet in the temperature range 900 to 1400 F (482 to 760 C)

NASA Technical Reports Server (NTRS)

Wilson, D. J.

1972-01-01

Time-dependent notch sensitivity of Inconel 718 sheet occurred at 900 to 1200 F when notched specimens were loaded below the yield strength, and tests on smooth specimens showed that small amounts of creep consumed large fractions of creep-rupture life. The severity of the notch sensitivity decreased with decreasing solution treatment temperature and increasing time and/or temperature of the aging treatment. Elimination of the notch sensitivity was correlated with a change in the dislocation mechanism from shearing to by-passing precipitate particles.

Experiential training for enhancing intercultural sensitivity.

PubMed

Jain, Sachin

2013-01-01

This project aims to enhance intercultural sensitivity using cross-cultural movies and focused group discussions with invited guests. Both treatment and control groups consisted of 9 Caucasian participants. The researcher conducted 8 group sessions with the participants of treatment group. Pre and post intervention data were collected on the Intercultural Sensitivity Scale. Results show that there was a significant increase in the participants' scores in the treatment group and not a significant difference in participants' pre and post scores in the control group. Further analysis on the five different dimensions of the Intercultural Sensitivity Scale was also conducted.

Role of Prefrontal Serotonergic and Dopaminergic Systems in Encounter-Induced Hyperactivity in Methamphetamine-Sensitized Mice.

PubMed

Tanaka, Tatsunori; Ago, Yukio; Umehara, Chiaki; Imoto, Emina; Hasebe, Shigeru; Hashimoto, Hitoshi; Takuma, Kazuhiro; Matsuda, Toshio

2017-05-01

Isolation-reared mice show social encounter-induced hyperactivity with activation of prefrontal serotonergic and dopaminergic systems, but it is not known whether this stress response is observed in other pathological conditions. Here we examined whether the social encounter stimulation induces abnormal behavior during withdrawal in chronic methamphetamine-treated mice. To induce methamphetamine-induced behavioral sensitization, male mice were injected with methamphetamine (1 mg/kg) once daily for 7 days. The encounter with an intruder elicited hyperactivity 24 h after the last injection of methamphetamine in methamphetamine-sensitized mice. This response was observed even as long as 2 weeks after withdrawal of methamphetamine. The encounter increased c-Fos expression in the prefrontal cortex, dorsal raphe nucleus and ventral tegmental area in methamphetamine-sensitized mice, while it did not in control mice. Furthermore, the encounter increased extracellular serotonin (5-HT) and dopamine, but not noradrenaline, levels in the prefrontal cortex in methamphetamine-sensitized mice. Local injection of 5,7-dihydroxytryptamine and 6-hydroxydopamine into the prefrontal cortex attenuated encounter-induced hyperactivity in methamphetamine-sensitized mice and it markedly decreased prefrontal 5-HT and dopamine levels, respectively. Pharmacological analysis showed that the encounter-induced hyperactivity is mediated by dopamine D1 receptors and 5-HT2A receptors and attenuated by anxiolytics and antidepressants such as diazepam, osemozotan and selective 5-HT reuptake inhibitors. The effect of paroxetine was blocked by the 5-HT3 receptor antagonist azasetron. The present study shows that psychological stress elicits hyperactivity with activation of prefrontal 5-HT and dopamine systems in methamphetamine-dependent mice and suggests that the abnormal behavior is associated with anxiety and depression. © The Author 2016. Published by Oxford University Press on behalf of CINP.

Aging properties of Kodak type 101 emulsions

NASA Technical Reports Server (NTRS)

Dohne, B.; Feldman, U.; Neupert, W.

1984-01-01

Aging tests for several batches of Kodak type 101 emulsion show that storage conditions significantly influence how well the film will maintain its sensitometric properties, with sensitivity and density increasing to a maximum during this period. Any further aging may result in higher fog levels and sensitivity loss. It is noted that storage in an environment free of photographically active compounds allows film property optimization, and that film batches with different sensitivities age differently. Emulsions with maximum 1700-A sensitivity are 2.5 times faster than those at the low end of the sensitivity scale. These sensitive emulsions exhibit significantly accelerated changes in aging properties. Their use in space applications requires careful consideration of time and temperature profiles, encouraging the use of less sensitive emulsions when the controllability of these factors is limited.

Tree-ring isotopes reveal drought sensitivity in trees killed by spruce beetle outbreaks in south-central Alaska.

PubMed

Csank, Adam Z; Miller, Amy E; Sherriff, Rosemary L; Berg, Edward E; Welker, Jeffrey M

2016-10-01

Increasing temperatures have resulted in reduced growth and increased tree mortality across large areas of western North American forests. We use tree-ring isotope chronologies (δ 13 C and δ 18 O) from live and dead trees from four locations in south-central Alaska, USA, to test whether white spruce trees killed by recent spruce beetle (Dendroctonus rufipennis Kirby) outbreaks showed evidence of drought stress prior to death. Trees that were killed were more sensitive to spring/summer temperature and/or precipitation than trees that survived. At two of our sites, we found greater correlations between the δ 13 C and δ 18 O chronologies and spring/summer temperatures in dead trees than in live trees, suggesting that trees that are more sensitive to temperature-induced drought stress are more likely to be killed. At one site, the difference between δ 13 C in live and dead trees was related to winter/spring precipitation, with dead trees showing stronger correlations between δ 13 C and precipitation, again suggesting increased water stress in dead trees. At all sites where δ 18 O was measured, δ 18 O chronologies showed the greatest difference in climate response between live and dead groups, with δ 18 O in live trees correlating more strongly with late winter precipitation than dead trees. Our results indicate that sites where trees are already sensitive to warm or dry early growing-season conditions experienced the most beetle-kill, which has important implications for forecasting future mortality events in Alaska. © 2016 by the Ecological Society of America.

The efficacy of using computer-aided detection (CAD) for detection of breast cancer in mammography screening: a systematic review.

PubMed

Henriksen, Emilie L; Carlsen, Jonathan F; Vejborg, Ilse Mm; Nielsen, Michael B; Lauridsen, Carsten A

2018-01-01

Background Early detection of breast cancer (BC) is crucial in lowering the mortality. Purpose To present an overview of studies concerning computer-aided detection (CAD) in screening mammography for early detection of BC and compare diagnostic accuracy and recall rates (RR) of single reading (SR) with SR + CAD and double reading (DR) with SR + CAD. Material and Methods PRISMA guidelines were used as a review protocol. Articles on clinical trials concerning CAD for detection of BC in a screening population were included. The literature search resulted in 1522 records. A total of 1491 records were excluded by abstract and 18 were excluded by full text reading. A total of 13 articles were included. Results All but two studies from the SR vs. SR + CAD group showed an increased sensitivity and/or cancer detection rate (CDR) when adding CAD. The DR vs. SR + CAD group showed no significant differences in sensitivity and CDR. Adding CAD to SR increased the RR and decreased the specificity in all but one study. For the DR vs. SR + CAD group only one study reported a significant difference in RR. Conclusion All but two studies showed an increase in RR, sensitivity and CDR when adding CAD to SR. Compared to DR no statistically significant differences in sensitivity or CDR were reported. Additional studies based on organized population-based screening programs, with longer follow-up time, high-volume readers, and digital mammography are needed to evaluate the efficacy of CAD.

Sensitive skin and stratum corneum reactivity to household cleaning products.

PubMed

Goffin, V; Piérard-Franchimont, C; Piérard, G E

1996-02-01

Products intended for individuals with sensitive skin are being increasingly developed by formulators of household cleaning products. However, there is currently no consensus about the definition and recognition of the biological basis of sensitive skin. We sought to determine the relation between the nature of environmental threat perceived as aggressive by panelists, and the stratum corneum reactivity to household cleaning products as measured by the corneosurfametry test. Results indicate substantial differences in irritancy potential between proprietary products. Corneosurfametry data show significant differences in stratum corneum reactivity between, on the one hand, individuals with either non-sensitive skin or skin sensitive to climate/fabrics, and, on the other hand, individuals with detergent-sensitive skin. It is concluded that sensitive skin is not one single condition. Sound information in rating detergent-sensitive skin may be gained by corneosurfametry.

Sensitivity of Earth Wheat Markets to Space Weather: Comparative Analysis based on data from Medieval European Markets

NASA Astrophysics Data System (ADS)

Pustil'Nik, Lev

We consider a problem of the possible influence of unfavorable states of the space weather on agriculture markets through the chain of connections: "space weather"-"earth weather"- "agriculture crops"-"price reaction". We show that new manifestations of "space weather"- "earth weather" relations discovered in the recent time allow revising a wide range of the expected solar-terrestrial connections. In the previous works we proposed possible mechanisms of wheat market reaction on the specific unfavorable states of space weather in the form of price bursts and price asymmetry. We point out that implementation of considered "price reaction scenarios" is possible only for the case of simultaneous realization of several necessary conditions: high sensitivity of local earth weather in the selected region to space weather; the state of "high risk agriculture" in the selected agriculture zone; high sensitivity of agricultural market to a possible deficit of yield. Results of our previous works (I, II), including application of this approach to the Medieval England wheat market (1250-1700) and to the modern USA durum market (1910-1992), showed that connection between wheat price bursts and space weather state in these cases was absolutely real. The aim of the present work is to answer the question why wheat markets in one selected region may be sensitive to a space weather factor, while in other regions wheat markets demonstrate absolutely indifferent reaction on the space weather. For this aim, we consider dependence of sensitivity of wheat markets to space weather as a function of their location in different climatic zones of Europe. We analyze a database of 95 European wheat markets from 14 countries for the 600-year period (1260-1912). We show that the observed sensitivity of wheat markets to space weather effects is controlled, first of all, by a type of predominant climate in different zones of agricultural production. Wheat markets in the Northern and, partly, in Central Europe (England, Holland, Belgium) show high sensitivity to space weather in minimum states of solar activity, when excess of the high energy cosmic ray stimulate additional cloudiness and precipitation. In the same time, wheat markets in the Southern Europe (Spain, Italy) show high sensitivity to space weather state in the opposite (maximum) phase of solar activity when a deficit of cosmic ray entering into the earth atmosphere leads to decrease of cloudiness and to increase of probability of drought weather periods. We demonstrate that the large part of markets in the Central Europe zone show absence of any effects of sensitivity to space weather state and show that this North-South asymmetry is in good accordance with the suggested model of expected wheat market reaction. We discuss possible increasing of sensitivity of wheat markets to space weather effects under conditions of fast and drastic change of modern climate with a shift of numerous agriculture regions to the state of "high risk agriculture zone".

Diagnosis of Normal and Abnormal Color Vision with Cone-Specific VEPs.

PubMed

Rabin, Jeff C; Kryder, Andrew C; Lam, Dan

2016-05-01

Normal color vision depends on normal long wavelength (L), middle wavelength (M), and short wavelength sensitive (S) cones. Hereditary "red-green" color vision deficiency (CVD) is due to a shift in peak sensitivity or lack of L or M cones. Hereditary S cone CVD is rare but can be acquired as an early sign of disease. Current tests detect CVD but few diagnose type or severity, critical for linking performance to real-world demands. The anomaloscope and newer subjective tests quantify CVD but are not applicable to infants or cognitively impaired patients. Our purpose was to develop an objective test of CVD with sensitivity and specificity comparable to current tests. A calibrated visual-evoked potential (VEP) display and Food and Drug Administration-approved system was used to record L, M, and S cone-specific pattern-onset VEPs from 18 color vision normals (CVNs) and 13 hereditary CVDs. VEP amplitudes and latencies were compared between groups to establish VEP sensitivity and specificity. Cone VEPs show 100% sensitivity for diagnosis of CVD and 94% specificity for confirming CVN. L cone (protan) CVDs showed a significant increase in L cone latency (53.1 msec, P < 0.003) and decreased amplitude (10.8 uV, P < 0.0000005) but normal M and S cone VEPs ( P > 0.31). M cone (deutan) CVDs showed a significant increase in M cone latency (31.0 msec, P < 0.000004) and decreased amplitude (8.4 uV, P < 0.006) but normal L and S cone VEPs ( P > 0.29). Cone-specific VEPs offer a rapid, objective test to diagnose hereditary CVD and show potential for detecting acquired CVD in various diseases. This paper describes the efficacy of cone-specific color VEPs for quantification of normal and abnormal color vision. The rapid, objective nature of this approach makes it suitable for detecting color sensitivity loss in infants and the cognitively impaired.

Modelling the sensitivity of soil mercury storage to climate-induced changes in soil carbon pools

NASA Astrophysics Data System (ADS)

Hararuk, O.; Obrist, D.; Luo, Y.

2013-04-01

Substantial amounts of mercury (Hg) in the terrestrial environment reside in soils and are associated with soil organic carbon (C) pools, where they accumulated due to increased atmospheric deposition resulting from anthropogenic activities. The purpose of this study was to examine potential sensitivity of surface soil Hg pools to global change variables, particularly affected by predicted changes in soil C pools, in the contiguous US. To investigate, we included a soil Hg component in the Community Land Model based on empirical statistical relationships between soil Hg / C ratios and precipitation, latitude, and clay; and subsequently explored the sensitivity of soil C and soil Hg densities (i.e., areal-mass) to climate scenarios in which we altered annual precipitation, carbon dioxide (CO2) concentrations and temperature. Our model simulations showed that current sequestration of Hg in the contiguous US accounted for 15 230 metric tons of Hg in the top 0-40 cm of soils, or for over 300 000 metric tons when extrapolated globally. In the simulations, US soil Hg pools were most sensitive to changes in precipitation because of strong effects on soil C pools, plus a direct effect of precipitation on soil Hg / C ratios. Soil Hg pools were predicted to increase beyond present-day values following an increase in precipitation amounts and decrease following a reduction in precipitation. We found pronounced regional differences in sensitivity of soil Hg to precipitation, which were particularly high along high-precipitation areas along the West and East Coasts. Modelled increases in CO2 concentrations to 700 ppm stimulated soil C and Hg accrual, while increased air temperatures had small negative effects on soil C and Hg densities. The combined effects of increased CO2, increased temperature and increased or decreased precipitation were strongly governed by precipitation and CO2 showing pronounced regional patterns. Based on these results, we conclude that the combination of precipitation and CO2 should be emphasised when assessing how climate-induced changes in soil C may affect sequestration of Hg in soils.

Brain imaging of pain sensitization in patients with knee osteoarthritis.

PubMed

Pujol, Jesus; Martínez-Vilavella, Gerard; Llorente-Onaindia, Jone; Harrison, Ben J; López-Solà, Marina; López-Ruiz, Marina; Blanco-Hinojo, Laura; Benito, Pere; Deus, Joan; Monfort, Jordi

2017-09-01

A relevant aspect in osteoarthritic pain is neural sensitization. This phenomenon involves augmented responsiveness to painful stimulation and may entail a clinically worse prognosis. We used functional magnetic resonance imaging (fMRI) to study pain sensitization in patients with knee osteoarthritis. Sixty patients were recruited and pain sensitization was clinically defined on the basis of regional spreading of pain (spreading sensitization) and increased pain response to repeated stimulation (temporal summation). Functional magnetic resonance imaging testing involved assessing brain responses to both pressure and heat stimulation. Thirty-three patients (55%) showed regional pain spreading (simple sensitization) and 19 patients (32%) showed both regional spreading and temporal summation. Sensitized patients were more commonly women. Direct painful pressure stimulation of the joint (articular interline) robustly activated all of the neural elements typically involved in pain perception, but did not differentiate sensitized and nonsensitized patients. Painful pressure stimulation on the anterior tibial surface (sensitized site) evoked greater activation in sensitized patients in regions typically involved in pain and also beyond these regions, extending to the auditory, visual, and ventral sensorimotor cortices. Painful heat stimulation of the volar forearm did not discriminate the sensitization phenomenon. Results confirm the high prevalence of pain sensitization secondary to knee osteoarthritis. Relevantly, the sensitization phenomenon was associated with neural changes extending beyond strict pain-processing regions with enhancement of activity in general sensory, nonnociceptive brain areas. This effect is in contrast to the changes previously identified in primary pain sensitization in fibromyalgia patients presenting with a weakening of the general sensory integration.

Contrasting effects of elevated CO2 and warming on temperature sensitivity of soil organic matter decomposition in a Chinese paddy field.

PubMed

Chen, Zhaozhi; Wang, Bingyu; Wang, Jinyang; Pan, Genxing; Xiong, Zhengqin

2015-10-01

Climate changes including elevated CO2 and temperature have been known to affect soil carbon (C) storage, while the effects of climate changes on the temperature sensitivity of soil organic matter (SOM) are unclear. A 365-day laboratory incubation was used to investigate the temperature sensitivity for decomposition of labile (Q 10-L) and recalcitrant (Q 10-R) SOMs by comparing the time required to decompose a given amount of C at 25 and 35 °C. Soils were collected from a paddy field that was subjected to four treatments: ambient CO2 and temperature, elevated CO2 (500 μmol/mol), enhanced temperature (+2 °C), and their combination. The results showed that the temperature sensitivity of SOM decomposition increased with increasing SOM recalcitrance in this paddy soil (Q 10-L = 2.21 ± 0.16 vs. Q 10-R = 2.78 ± 0.42; mean ± SD). Elevated CO2 and enhanced temperature showed contrasting effects on the temperature sensitivity of SOM decomposition. Elevated CO2 stimulated Q 10-R but had no effect on Q 10-L; in contrast, enhanced temperature increased Q 10-L but had no effect on Q 10-R. Furthermore, the elevated CO2 combined with enhanced temperature treatment significantly increased Q 10-L and Q 10-R by 18.9 and 10.2 %, respectively, compared to the ambient conditions. Results suggested that the responses of SOM to temperature, especially for the recalcitrant SOM pool, were altered by climate changes. The greatly enhanced temperature sensitivity of SOM decomposition by elevated CO2 and temperature indicates that more CO2 will be released to the atmosphere and losses of soil C may be even greater than that previously expected in paddy field.

Extreme ultraviolet patterning of tin-oxo cages

NASA Astrophysics Data System (ADS)

Haitjema, Jarich; Zhang, Yu; Vockenhuber, Michaela; Kazazis, Dimitrios; Ekinci, Yasin; Brouwer, Albert M.

2017-07-01

We report on the extreme ultraviolet (EUV) patterning performance of tin-oxo cages. These cage molecules were already known to function as a negative tone photoresist for EUV radiation, but in this work, we significantly optimized their performance. Our results show that sensitivity and resolution are only meaningful photoresist parameters if the process conditions are optimized. We focus on contrast curves of the materials using large area EUV exposures and patterning of the cages using EUV interference lithography. It is shown that baking steps, such as postexposure baking, can significantly affect both the sensitivity and contrast in the open-frame experiments as well as the patterning experiments. A layer thickness increase reduced the necessary dose to induce a solubility change but decreased the patterning quality. The patterning experiments were affected by minor changes in processing conditions such as an increased rinsing time. In addition, we show that the anions of the cage can influence the sensitivity and quality of the patterning, probably through their effect on physical properties of the materials.

Near-infrared fluorescence glucose sensing based on glucose/galactose-binding protein coupled to 651-Blue Oxazine

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

Khan, Faaizah; Pickup, John C., E-mail: john.pickup@kcl.ac.uk

Highlights: •We showed that the NIR fluorophore, 651-Blue Oxazine, is solvatochromic (polarity sensitive). •Blue Oxazine was covalently attached to mutants of glucose/galactose-binding protein (GBP). •Fluorescence intensity of GBP-Blue Oxazine increased with addition of glucose. •Fluorescence from bead-immobilised GBP-Blue Oxazine was detectable through skin in vitro. •This shows proof-of-concept for non-invasive glucose sensing using GBP-Blue Oxazine. -- Abstract: Near-infrared (NIR) fluorescent dyes that are environmentally sensitive or solvatochromic are useful tools for protein labelling in in vivo biosensor applications such as glucose monitoring in diabetes since their spectral properties are mostly independent of tissue autofluorescence and light scattering, and they offermore » potential for non-invasive analyte sensing. We showed that the fluorophore 651-Blue Oxazine is polarity-sensitive, with a marked reduction in NIR fluorescence on increasing solvent polarity. Mutants of glucose/galactose-binding protein (GBP) used as the glucose receptor were site-specifically and covalently labelled with Blue Oxazine using click chemistry. Mutants H152C/A213R and H152C/A213R/L238S showed fluorescence increases of 15% and 21% on addition of saturating glucose concentrations and binding constants of 6 and 25 mM respectively. Fluorescence responses to glucose were preserved when GBP-Blue Oxazine was immobilised to agarose beads, and the beads were excited by NIR light through a mouse skin preparation studied in vitro. We conclude GBP-Blue Oxazine shows proof-of-concept as a non-invasive continuous glucose sensing system.« less

Duration-sensitive neurons in the inferior colliculus of horseshoe bats: adaptations for using CF-FM echolocation pulses.

PubMed

Luo, Feng; Metzner, Walter; Wu, Feijian; Wu, Feijian J; Zhang, Shuyi; Zhang, Shuyi Y; Chen, Qicai; Chen, Qicai C

2008-01-01

The present study examines duration-sensitive neurons in the inferior colliculus (IC) of the least horseshoe bat, Rhinolophus pusillus, from China. In contrast to other bat species tested for duration selectivity so far, echolocation pulses emitted by horseshoe bats are generally longer and composed of a long constant-frequency (CF) component followed by a short downward frequency-modulated (FM) sweep (CF-FM pulse). We used combined CF-FM pulses to analyze the differential effects that these two pulse components had on the duration tuning in neurons of the horseshoe bat's IC. Consistent with results from other mammals, duration-sensitive neurons found in the least horseshoe bat fall into three main classes: short-pass, band-pass, and long-pass. Using a CF stimulus alone, 54% (51/95) of all IC neurons showed at least one form of duration selectivity at one or more stimulus intensities. In 65 of the 95 IC neurons tested with CF pulses, we were also able to test their duration selectivity for a combined CF-FM pulse, which increased the ratio of duration-sensitive neurons to 66% (43/65). Seven to 15 neurons that failed to show duration tuning for CF bursts became duration sensitive for CF-FM pulses, with most of them exhibiting short-pass (depending on stimulus intensity, between 4 and 8 neurons) or band-pass tuning (1-3 neurons). Increasing stimulus intensities did not affect the duration tuning in 53% (23/43) of duration-sensitive neurons for CF bursts and in about 26% (7/27) for CF-FM stimuli. In the remaining neurons, increasing sound levels generally reduced the ratio of duration-sensitive neurons to 33% for CF and 37% for CF-FM stimulation. In those that remained duration sensitive, louder CF bursts shortened best durations in band-pass neurons and cutoff durations in short- and long-pass neurons, whereas louder CF-FM stimuli reduced the cutoff durations only in short-pass neurons. Bandwidths of band-pass neurons were not significantly affected by any stimulus configuration, with only a slight trend for increasing bandwidths for louder CF bursts (but not CF-FM stimuli). Best durations and cutoff durations reached higher values than those in the other bat species examined so far and roughly match the longer durations of echolocation pulses emitted by horseshoe bats. Therefore presentation of a CF-FM stimulus improved the duration sensitivity in IC neurons by increasing the ratio of duration-tuned neurons and making them less susceptible to changes in signal intensity.

Effects of time delay and pitch control sensitivity in the flared landing

NASA Technical Reports Server (NTRS)

Berthe, C. J.; Chalk, C. R.; Wingarten, N. C.; Grantham, W.

1986-01-01

Between December 1985 and January 1986, a flared landing program was conducted, using the USAF Total In-Flight simulator airplane, to examine time delay effects in a formal manner. Results show that as pitch sensitivity is increased, tolerance to time delay decreases. With the proper selection of pitch sensitivity, Level I performance was maintained with time delays ranging from 150 milliseconds to greater than 300 milliseconds. With higher sensitivity, configurations with Level I performance at 150 milliseconds degraded to level 2 at 200 milliseconds. When metrics of time delay and pitch sensitivity effects are applied to enhance previously developed predictive criteria, the result is an improved prediction technique which accounts for significant closed loop items.

Auditory evoked potential could reflect emotional sensitivity and impulsivity

PubMed Central

Kim, Ji Sun; Kim, Sungkean; Jung, Wookyoung; Im, Chang-Hwan; Lee, Seung-Hwan

2016-01-01

Emotional sensitivity and impulsivity could cause interpersonal conflicts and neuropsychiatric problems. Serotonin is correlated with behavioral inhibition and impulsivity. This study evaluated whether the loudness dependence of auditory evoked potential (LDAEP), a potential biological marker of central serotonergic activity, could reflect emotional sensitivity and impulsivity. A total of 157 healthy individuals were recruited, who performed LDAEP and Go/Nogo paradigms during electroencephalogram measurement. Barratt impulsivity scale (BIS), Conners’ Adult ADHD rating scale (CAARS), and affective lability scale (ALS) were evaluated. Comparison between low and high LDAEP groups was conducted for behavioural, psychological, and event-related potential (ERP) measures. The high LDAEP group showed significantly increased BIS, a subscale of the CAARS, ALS, and false alarm rate of Nogo stimuli compared to the low LDAEP group. LDAEP showed significant positive correlations with the depression scale, ALS scores, subscale of the CAARS and Nogo-P3 amplitude. In the source activity of Nogo-P3, the cuneus, lingual gyrus, and precentral gyrus activities were significantly increased in the high LDAEP group. Our study revealed that LDAEP could reflect emotional sensitivity and impulsivity. LDAEP, an auditory evoked potential could be a useful tool to evaluate emotional regulation. PMID:27910865

Antiobesity Effect of a Small Molecule Repressor of RORγ

PubMed Central

Chang, Mi Ra; He, Yuanjun; Khan, Tanya M.; Kuruvilla, Dana S.; Garcia-Ordonez, Ruben; Corzo, Cesar A.; Unger, Thaddeus J.; White, David W.; Khan, Susan; Lin, Li; Cameron, Michael D.; Kamenecka, Theodore M.

2015-01-01

The orphan nuclear receptor RORγ is a key regulator for T helper 17 (TH17) cell differentiation, which regulates metabolic and circadian rhythm genes in peripheral tissues. Previously, it was shown that the small molecule inverse agonist of RORγ SR1555 [1-(4-((4′-(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)-[1,1′-biphenyl]-4-yl)methyl)piperazin-1-yl) ethanone] suppressed TH17 differentiation and stimulated induced T regulatory (iTreg) cells. Here, we show that treatment of cultured pre-adipocyctes with SR1555 represses the expression of RORγ while leading to increased expression of FGF21 and adipoQ. Chronic administration of SR1555 to obese diabetic mice resulted in a modest reduction in food intake accompanied with significant reduction in fat mass, resulting in reduced body weight and improved insulin sensitivity. Analysis ex vivo of treated mice demonstrates that SR1555 induced expression of the thermogenic gene program in fat depots. Further studies in cultured cells showed that SR1555 inhibited activation of hormone-sensitive lipase and increased fatty acid oxidation. Combined, these results suggest that pharmacological repression of RORγ may represent a strategy for treatment of obesity by increasing thermogenesis and fatty acid oxidation, while inhibition of hormone-sensitive lipase activity results in a reduction of serum free fatty acids, leading to improved peripheral insulin sensitivity. PMID:25904554

Increased sensitivity to mitochondrial permeability transition and myonuclear translocation of endonuclease G in atrophied muscle of physically active older humans.

PubMed

Gouspillou, Gilles; Sgarioto, Nicolas; Kapchinsky, Sophia; Purves-Smith, Fennigje; Norris, Brandon; Pion, Charlotte H; Barbat-Artigas, Sébastien; Lemieux, Francois; Taivassalo, Tanja; Morais, José A; Aubertin-Leheudre, Mylène; Hepple, Russell T

2014-04-01

Mitochondrial dysfunction is implicated in skeletal muscle atrophy and dysfunction with aging, with strong support for an increased mitochondrial-mediated apoptosis in sedentary rodent models. Whether this applies to aged human muscle is unknown, nor is it clear whether these changes are caused by sedentary behavior. Thus, we examined mitochondrial function [respiration, reactive oxygen species (ROS) emission, and calcium retention capacity (CRC)] in permeabilized myofibers obtained from vastus lateralis muscle biopsies of healthy physically active young (23.7±2.7 yr; mean±SD) and older (71.2±4.9 yr) men. Although mitochondrial ROS and maximal respiratory capacity were unaffected, the acceptor control ratio was reduced by 18% with aging, suggesting mild uncoupling of oxidative phosphorylation. CRC was reduced by 50% with aging, indicating sensitization of the mitochondrial permeability transition pore (mPTP) to apoptosis. Consistent with the mPTP sensitization, older muscles showed a 3-fold greater fraction of endonuclease G (a mitochondrial proapoptotic factor)-positive myonuclei. Aged muscles also had lower mitophagic potential, based on a 43% reduction in Parkin to the voltage-dependent anion channel (VDAC) protein ratio. Collectively, these results show that mitochondrial-mediated apoptotic signaling is increased in older human muscle and suggest that accumulation of dysfunctional mitochondria with exaggerated apoptotic sensitivity is due to impaired mitophagy.

Super-sensitive two-wavelength fringe projection profilometry with 2-sensitivities temporal unwrapping

NASA Astrophysics Data System (ADS)

Servin, Manuel; Padilla, Moises; Garnica, Guillermo

2018-07-01

Since the early 1970s, optical two-wavelength phase-metrology (TWPM) has been used in a wide variety of experimental set ups. In TWPM one may compute the phase-sum and the phase-difference of two close phase measurements. Early TWPM optically computed the phase difference and phase sum by double exposure holography. However soon after, TWPM became almost synonymous to calculating the phase-difference only. The more sensitive phase-sum was largely forgotten. The standard application for phase-difference TWPM is to extend the phase measurement depth without phase-unwrapping for discontinuous phase-objects. This phase-difference, while non-wrapped, decreases however the signal-to-noise ratio (SNR) of the estimated phase. On the other hand, the phase-sum increases the phase sensitivity, and the SNR of the estimated phase. In spite of these two great advantages, the use of the phase-sum in TWPM has been almost ignored. In this paper we review and set the stage for digital TWPM for super-sensitive phase-sum estimation. This is coupled with two-sensitivity phase-unwrapping to obtain extended-range super-sensitive fringe-projection profilometry estimations. Here we mathematically prove, and experimentally show that using the phase-sum one obtains a huge increase in SNR with respect to using the phase-difference alone. The pioneer works on double exposure TWPM holography that uses the phase-difference and phase-sum are also properly acknowledged. Finally, two experimental results from fringe-projection profilometry that clearly show the huge SNR gain of the phase-sum, with respect to the phase-difference is now mathematically well established.

The dependence of binocular contrast sensitivities on binocular single vision in normal and amblyopic human subjects

PubMed Central

Hood, A S; Morrison, J D

2002-01-01

We have measured monocular and binocular contrast sensitivities in response to medium to high spatial frequencies of vertical sinusoidal grating patterns in normal subjects, anisometropic amblyopes, strabismic amblyopes and non-amblyopic esotropes. On binocular viewing, contrast sensitivities were slightly but significantly increased in normal subjects, markedly increased in anisometropes and esotropes with anomalous binocular single vision (BSV) and significantly reduced in esotropes and exotropes without BSV. Application of a prismatic correction to the strabismic eye in order to achieve bifoveal stimulation resulted in a significant reduction in contrast sensitivity in esotropes with and without anomalous BSV, in exotropes and in non-amblyopic esotropes. Control experiments in normal subjects with monocular viewing showed that degradative effects of the prism occurred only with high prism powers and at high spatial frequencies, thus establishing that the reduced contrast sensitivities were the consequence of bifoveal stimulation rather than optical degradation. Displacement of the image of the grating pattern by 2 deg in normal subjects and anisometropes by a dichoptic method to simulate a small angle esotropia had no effect on the contrast sensitivities recorded through the companion eye. By contrast, esotropes showed similar reductions in contrast sensitivity to those obtained with the prism experiments, confirming a fundamental difference between subjects with normal and abnormal ocular alignments. The results have thus established a suppressive action of the fovea of the amblyopic eye acting on the companion, non-amblyopic eye and indicate that correction of ocular misalignments in adult esotropes may be disadvantageous to binocular visual performance. PMID:11956347

A competitive trade-off limits the selective advantage of increased antibiotic production.

PubMed

Gerardin, Ylaine; Springer, Michael; Kishony, Roy

2016-09-26

In structured environments, antibiotic-producing microorganisms can gain a selective advantage by inhibiting nearby competing species 1 . However, despite their genetic potential 2,3 , natural isolates often make only small amounts of antibiotics, and laboratory evolution can lead to loss rather than enhancement of antibiotic production 4 . Here, we show that, due to competition with antibiotic-resistant cheater cells, increased levels of antibiotic production can actually decrease the selective advantage to producers. Competing fluorescently labelled Escherichia coli colicin producers with non-producing resistant and sensitive strains on solid media, we found that although producer colonies can greatly benefit from the inhibition of nearby sensitive colonies, this benefit is shared with resistant colonies growing in their vicinity. A simple model, which accounts for such local competitive and inhibitory interactions, suggests that the advantage of producers varies non-monotonically with the amount of production. Indeed, experimentally varying the amount of production shows a peak in selection for producers, reflecting a trade-off between benefit gained by inhibiting sensitive competitors and loss due to an increased contribution to resistant cheater colonies. These results help explain the low level of antibiotic production observed for natural species and can help direct laboratory evolution experiments selecting for increased or novel production of antibiotics.

Autonomic, functional, skeletal muscle, and cardiac abnormalities are associated with increased ergoreflex sensitivity in mitochondrial disease.

PubMed

Giannoni, Alberto; Aimo, Alberto; Mancuso, Michelangelo; Piepoli, Massimo Francesco; Orsucci, Daniele; Aquaro, Giovanni Donato; Barison, Andrea; De Marchi, Daniele; Taddei, Claudia; Cameli, Matteo; Raglianti, Valentina; Siciliano, Gabriele; Passino, Claudio; Emdin, Michele

2017-12-01

Mitochondrial disease (MD) is a genetic disorder affecting skeletal muscles, with possible myocardial disease. The ergoreflex, sensitive to skeletal muscle work, regulates ventilatory and autonomic responses to exercise. We hypothesized the presence of an increased ergoreflex sensitivity in MD patients, its association with abnormal ventilatory and autonomic responses, and possibly with subclinical cardiac involvement. Twenty-five MD patients (aged 46 ± 3 years, 32% male) with skeletal myopathy but without known cardiac disease, underwent a thorough evaluation including BNPs, galectin-3, soluble suppression of tumorigenesis 2 (sST2), high sensitivity troponin T/I, catecholamines, ECG, 24-h ECG recording, cardiopulmonary exercise testing, echocardiography, cardiac/muscle magnetic resonance (C/MMR), and ergoreflex assessment. Thirteen age- and sex-matched healthy controls were chosen. Among these myopathic patients, subclinical cardiac damage was detected in up to 80%, with 44% showing fibrosis at CMR. Ergoreflex sensitivity was markedly higher in patients than in controls (64% vs. 37%, P < 0.001), and correlated with muscle fat to water ratio and extracellular volume at MMR (both P < 0.05). Among patients, ergoreflex sensitivity was higher in those with cardiac involvement (P = 0.034). Patients showed a lower peak oxygen consumption (VO 2 /kg) than controls (P < 0.001), as well as ventilatory inefficiency (P = 0.024). Ergoreflex sensitivity correlated with reduced workload and peak VO 2 /kg (both P < 0.001), and several indicators of autonomic imbalance (P < 0.05). Plasma norepinephrine was the unique predictor of myocardial fibrosis at univariate analysis (P < 0.05). Skeletal myopathy in MD is characterized by enhanced ergoreflex sensitivity, which is associated with a higher incidence of cardiac involvement, exercise intolerance, and sympathetic activation. © 2017 The Authors. European Journal of Heart Failure © 2017 European Society of Cardiology.

The ice-core record - Climate sensitivity and future greenhouse warming

NASA Technical Reports Server (NTRS)

Lorius, C.; Raynaud, D.; Jouzel, J.; Hansen, J.; Le Treut, H.

1990-01-01

The prediction of future greenhouse-gas-warming depends critically on the sensitivity of earth's climate to increasing atmospheric concentrations of these gases. Data from cores drilled in polar ice sheets show a remarkable correlation between past glacial-interglacial temperature changes and the inferred atmospheric concentration of gases such as carbon dioxide and methane. These and other palaeoclimate data are used to assess the role of greenhouse gases in explaining past global climate change, and the validity of models predicting the effect of increasing concentrations of such gases in the atmosphere.

The effect of an atomically deposited layer of alumina on NiO in P-type dye-sensitized solar cells.

PubMed

Natu, Gayatri; Huang, Zhongjie; Ji, Zhiqiang; Wu, Yiying

2012-01-10

We present a systematic investigation of the fundamental effects of an atomically deposited alumina (AlO(x)H(y)) onto the NiO films in p-type dye-sensitized solar cells (p-DSCs). With P1 as the sensitizing dye and 0.1 M I(2) and 1.0 M LiI in 3-methoxypropionitrile as the electrolyte, one atomic layer deposition (ALD) cycle of alumina was used to achieve a 74% increase in the overall conversion efficiency of a NiO-based DSC. The open circuit voltage of the cells increased from 0.11 to 0.15 V, and the short circuit current density increased from 0.83 to 0.95 mA/cm(2). Adsorption isotherm studies were performed to show that the amount of dye adsorbed on the NiO-alumina film is slightly lower than the amount adsorbed on the nontreated NiO film. The increased J(sc) was therefore assigned to the increased efficiency of carrier collection at the semiconductor-FTO interface. Our study of the photocurrent onset potentials of NiO and NiO-alumina films with the chopped light measurement technique showed no definitive difference in the onset potential values. However, the DSCs based on NiO-alumina showed a higher recombination resistance value from the electrochemical impedance studies and a higher diode ideality factor from the V(oc) versus ln(light intensity) plots as compared to the DSCs based on untreated NiO. It has thus been established that the increase in V(oc) upon alumina treatment arises due to a higher resistance for electron-hole recombination across NiO surface locally.

Mechanical energy estimation during walking: validity and sensitivity in typical gait and in children with cerebral palsy.

PubMed

Van de Walle, P; Hallemans, A; Schwartz, M; Truijen, S; Gosselink, R; Desloovere, K

2012-02-01

Gait efficiency in children with cerebral palsy is usually quantified by metabolic energy expenditure. Mechanical energy estimations, however, can be a valuable supplement as they can be assessed during gait analysis and plotted over the gait cycle, thus revealing information on timing and sources of increases in energy expenditure. Unfortunately, little information on validity and sensitivity exists. Three mechanical estimation approaches: (1) centre of mass (CoM) approach, (2) sum of segmental energies (SSE) approach and (3) integrated joint power approach, were validated against oxygen consumption and each other. Sensitivity was assessed in typical gait and in children with diplegia. CoM approach underestimated total energy expenditure and showed poor sensitivity. SSE approach overestimated energy expenditure and showed acceptable sensitivity. Validity and sensitivity were best in the integrated joint power approach. This method is therefore preferred for mechanical energy estimation in children with diplegia. However, mechanical energy should supplement, not replace metabolic energy, as total energy expended is not captured in any mechanical approach. Copyright © 2011 Elsevier B.V. All rights reserved.

The Effect of the Thickness of the Sensitive Layer on the Performance of the Accumulating NOx Sensor

PubMed Central

Groß, Andrea; Richter, Miriam; Kubinski, David J.; Visser, Jacobus H.; Moos, Ralf

2012-01-01

A novel and promising method to measure low levels of NOx utilizes the accumulating sensor principle. During an integration cycle, incoming NOx molecules are stored in a sensitive layer based on an automotive lean NOx trap (LNT) material that changes its electrical resistivity proportional to the amount of stored NOx, making the sensor suitable for long-term detection of low levels of NOx. In this study, the influence of the thickness of the sensitive layer, prepared by multiple screen-printing, is investigated. All samples show good accumulating sensing properties for both NO and NO2. In accordance to a simplified model, the base resistance of the sensitive layer and the sensitivity to NOx decrease with increasing thickness. Contrarily, the sensor response time increases. The linear measurement range of all samples ends at a sensor response of about 30% resulting in an increase of the linearly detectable amount with the thickness. Hence, the variation of the thickness of the sensitive layer is a powerful tool to adapt the linear measurement range (proportional to the thickness) as well as the sensitivity (proportional to the inverse thickness) to the application requirements. Calculations combining the sensor model with the measurement results indicate that for operation in the linear range, about 3% of the LNT material is converted to nitrate.

Metacognitive Confidence Increases with, but Does Not Determine, Visual Perceptual Learning.

PubMed

Zizlsperger, Leopold; Kümmel, Florian; Haarmeier, Thomas

2016-01-01

While perceptual learning increases objective sensitivity, the effects on the constant interaction of the process of perception and its metacognitive evaluation have been rarely investigated. Visual perception has been described as a process of probabilistic inference featuring metacognitive evaluations of choice certainty. For visual motion perception in healthy, naive human subjects here we show that perceptual sensitivity and confidence in it increased with training. The metacognitive sensitivity-estimated from certainty ratings by a bias-free signal detection theoretic approach-in contrast, did not. Concomitant 3Hz transcranial alternating current stimulation (tACS) was applied in compliance with previous findings on effective high-low cross-frequency coupling subserving signal detection. While perceptual accuracy and confidence in it improved with training, there were no statistically significant tACS effects. Neither metacognitive sensitivity in distinguishing between their own correct and incorrect stimulus classifications, nor decision confidence itself determined the subjects' visual perceptual learning. Improvements of objective performance and the metacognitive confidence in it were rather determined by the perceptual sensitivity at the outset of the experiment. Post-decision certainty in visual perceptual learning was neither independent of objective performance, nor requisite for changes in sensitivity, but rather covaried with objective performance. The exact functional role of metacognitive confidence in human visual perception has yet to be determined.

Responses of glomus cells to hypoxia and acidosis are uncoupled, reciprocal and linked to ASIC3 expression: selectivity of chemosensory transduction

PubMed Central

Lu, Yongjun; Whiteis, Carol A; Sluka, Kathleen A; Chapleau, Mark W; Abboud, François M

2013-01-01

Carotid body glomus cells are the primary sites of chemotransduction of hypoxaemia and acidosis in peripheral arterial chemoreceptors. They exhibit pronounced morphological heterogeneity. A quantitative assessment of their functional capacity to differentiate between these two major chemical signals has remained undefined. We tested the hypothesis that there is a differential sensory transduction of hypoxia and acidosis at the level of glomus cells. We measured cytoplasmic Ca2+ concentration in individual glomus cells, isolated in clusters from rat carotid bodies, in response to hypoxia ( mmHg) and to acidosis at pH 6.8. More than two-thirds (68%) were sensitive to both hypoxia and acidosis, 19% were exclusively sensitive to hypoxia and 13% exclusively sensitive to acidosis. Those sensitive to both revealed significant preferential sensitivity to either hypoxia or to acidosis. This uncoupling and reciprocity was recapitulated in a mouse model by altering the expression of the acid-sensing ion channel 3 (ASIC3) which we had identified earlier in glomus cells. Increased expression of ASIC3 in transgenic mice increased pH sensitivity while reducing cyanide sensitivity. Conversely, deletion of ASIC3 in the knockout mouse reduced pH sensitivity while the relative sensitivity to cyanide or to hypoxia was increased. In this work, we quantify functional differences among glomus cells and show reciprocal sensitivity to acidosis and hypoxia in most glomus cells. We speculate that this selective chemotransduction of glomus cells by either stimulus may result in the activation of different afferents that are preferentially more sensitive to either hypoxia or acidosis, and thus may evoke different and more specific autonomic adjustments to either stimulus. PMID:23165770

Impervious surfaces and sewer pipe effects on stormwater runoff temperature

NASA Astrophysics Data System (ADS)

Sabouri, F.; Gharabaghi, B.; Mahboubi, A. A.; McBean, E. A.

2013-10-01

The warming effect of the impervious surfaces in urban catchment areas and the cooling effect of underground storm sewer pipes on stormwater runoff temperature are assessed. Four urban residential catchment areas in the Cities of Guelph and Kitchener, Ontario, Canada were evaluated using a combination of runoff monitoring and modelling. The stormwater level and water temperature were monitored at 10 min interval at the inlet of the stormwater management ponds for three summers 2009, 2010 and 2011. The warming effect of the ponds is also studied, however discussed in detail in a separate paper. An artificial neural network (ANN) model for stormwater temperature was trained and validated using monitoring data. Stormwater runoff temperature was most sensitive to event mean temperature of the rainfall (EMTR) with a normalized sensitivity coefficient (Sn) of 1.257. Subsequent levels of sensitivity corresponded to the longest sewer pipe length (LPL), maximum rainfall intensity (MI), percent impervious cover (IMP), rainfall depth (R), initial asphalt temperature (AspT), pipe network density (PND), and rainfall duration (D), respectively. Percent impervious cover of the catchment area (IMP) was the key parameter that represented the warming effect of the paved surfaces; sensitivity analysis showed IMP increase from 20% to 50% resulted in runoff temperature increase by 3 °C. The longest storm sewer pipe length (LPL) and the storm sewer pipe network density (PND) are the two key parameters that control the cooling effect of the underground sewer system; sensitivity analysis showed LPL increase from 345 to 966 m, resulted in runoff temperature drop by 2.5 °C.

Mounting a thermocouple of type E onto a Cu single crystal for use in a magnetically sensitive environment below 77 K

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

Potzuweit, Alexander; Schaffner, Anuschka; Jänsch, Heinz Julius, E-mail: heinz.jaensch@physik.uni-marburg.de

2014-09-01

Type E thermocouples show magnetic effects at liquid nitrogen temperature and below. This may cause trouble in experiments that are sensitive to magnetic stray fields like nuclear magnetic resonance, photoemission or high resolution electron energy loss spectroscopy. Here, a solution for the temperature measurement of a single crystal is presented. The authors weld a copper rod onto the back side of the single crystal, thereby relocating the sensitive sample from the thermocouple attachment position. They show that it is possible to measure the crystal temperature at the end of the rod while significantly reducing the ferromagnetic influence due to themore » increased distance.« less

Developmental Programming: Impact of Gestational Steroid and Metabolic Milieus on Mediators of Insulin Sensitivity in Prenatal Testosterone-Treated Female Sheep.

PubMed

Puttabyatappa, Muraly; Andriessen, Victoria; Mesquitta, Makeda; Zeng, Lixia; Pennathur, Subramaniam; Padmanabhan, Vasantha

2017-09-01

Prenatal testosterone (T) excess in sheep leads to peripheral insulin resistance (IR), reduced adipocyte size, and tissue-specific changes, with liver and muscle but not adipose tissue being insulin resistant. To determine the basis for the tissue-specific differences in insulin sensitivity, we assessed changes in negative (inflammation, oxidative stress, and lipotoxicity) and positive mediators (adiponectin and antioxidants) of insulin sensitivity in the liver, muscle, and adipose tissues of control and prenatal T-treated sheep. Because T excess leads to maternal hyperinsulinemia, fetal hyperandrogenism, and functional hyperandrogenism and IR in their female offspring, prenatal and postnatal interventions with antiandrogen, flutamide, and the insulin sensitizer rosiglitazone were used to parse out the contribution of androgenic and metabolic pathways in programming and maintaining these defects. Results showed that (1) peripheral IR in prenatal T-treated female sheep is related to increases in triglycerides and 3-nitrotyrosine, which appear to override the increase in high-molecular-weight adiponectin; (2) liver IR is a function of the increase in oxidative stress (3-nitrotyrosine) and lipotoxicity; (3) muscle IR is related to lipotoxicity; and (4) the insulin-sensitive status of visceral adipose tissue appears to be a function of the increase in antioxidants that likely overrides the increase in proinflammatory cytokines, macrophages, and oxidative stress. Prenatal and postnatal intervention with either antiandrogen or insulin sensitizer had partial effects in preventing or ameliorating the prenatal T-induced changes in mediators of insulin sensitivity, suggesting that both pathways are critical for the programming and maintenance of the prenatal T-induced changes and point to potential involvement of estrogenic pathways. Copyright © 2017 Endocrine Society.

Pilot evaluation of short-term changes in macular pigment and retinal sensitivity in different phenotypes of early age-related macular degeneration after carotenoid supplementation.

PubMed

Corvi, Federico; Souied, Eric H; Falfoul, Yousra; Georges, Anouk; Jung, Camille; Querques, Lea; Querques, Giuseppe

2017-06-01

To investigate the response of carotenoid supplementation in different phenotypes of early age-related macular degeneration (AMD) by measuring macular pigment optical density (MPOD) and retinal sensitivity. Consecutive patients with only medium/large drusen and only reticular pseudodrusen (RPD) and age-matched and sex-matched controls were enrolled. At baseline, participants underwent a complete ophthalmological examination including measurement of best-corrected visual acuity (BCVA), MPOD and retinal sensitivity. Patients were put on vitamin supplementation (lutein 10 mg/day, zeaxanthin 2 mg/day) and 3 months later underwent a repeated ophthalmological examination. Twenty patients with medium/large drusen, 19 with RPD and 15 control subjects were included. At baseline, in controls, mean MPOD and BCVA were significantly higher compared with RPD (p=0.001 and p=0.01) but similar to medium/large drusen (p=0.9 and p=0.4). Mean retinal sensitivity was significantly higher in controls compared with RPD and medium/large drusen (for all p<0.0001). After 3 months of carotenoid supplementation the mean MPOD significantly increased in RPD (p=0.002), thus showing no more difference compared with controls (p=0.3); no significant changes were found in mean retinal sensitivity and BCVA (p=0.3 and p=0.7). Medium/large drusen did not show significant changes on MPOD, retinal sensitivity and BCVA (p=0.5, p=0.7 and p=0.7, respectively). Patients with early AMD, especially RPD phenotype, show lower macular sensitivity and MPOD than controls. After supplementation, MPOD significantly increased in RPD. These results suggest different pathophysiology for RPD as compared with medium/large drusen and may open new ways to identifying further therapeutic targets in this phenotype of early AMD. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Temperature sensitivity of methanogenesis in a thermokarst lake sediment core

NASA Astrophysics Data System (ADS)

Heslop, J. K.; Walter Anthony, K. M.; Grosse, G.; Anthony, P.; Bondurant, A.

2016-12-01

Little is known about temperature sensitivity of permafrost organic carbon (OC) mineralization over time scales of years to centuries following thaw. Due to their formation and thaw histories, taliks (thaw bulbs) beneath thermokarst lakes provide a unique natural laboratory from which to examine how permafrost thawed in saturated anaerobic conditions responds to changes in temperature following long periods of time since thaw. We anaerobically incubated samples from a 590 cm thermokarst lake sediment core near Fairbanks, Alaska at four temperatures (0, 3, 10, and 25 ºC) bracketing observed talik temperatures. We show that since initial thaw 400 yr BP CH4 production shifts from being most sensitive to at lower (0-3 ºC; Q10-EC=1.15E7) temperatures to being most sensitive at higher (10-25 ºC; Q10-EC=67) temperatures. Frozen sediments collected from beneath the talik, thawed at the commencement of the incubation, had significant (p ≤ 0.05) increases in CH4 production rates at lower temperatures but did not show significant CH4 production rate increases at higher temperatures (10-25 ºC). We hypothesize the thawing of sediments removed a major barrier to C mineralization, leading to rapid initial permafrost C mineralization and preferential mineralization of the most biolabile OC compounds. In contrast, sediments which had been thawed beneath the lake for longer periods of time did not experience statistically significant increases in CH4 production at lower temperatures (0-10 ºC), but had high temperature sensitivities at higher temperatures (10-25 ºC). We believe these rate increases are due to warmer temperatures in the experimental incubations crossing activation energy thresholds, allowing previously recalcitrant fractions of OC to be utilized, and/or the presence of different microbial communities adapted to thawed sediments. Recently-deposited sediments at shallow depths in the lake core experienced increases in CH4 production across all incubation temperatures (Q10-ST=4.4).

Corrosion behavior of sensitized duplex stainless steel.

PubMed

Torres, F J; Panyayong, W; Rogers, W; Velasquez-Plata, D; Oshida, Y; Moore, B K

1998-01-01

The present work investigates the corrosion behavior of 2205 duplex stainless steel in 0.9% NaCl solution after various heat-treatments, and compares it to that of 316L austenitic stainless steel. Both stainless steels were heat-treated at 500, 650, and 800 degrees C in air for 1 h, followed by furnace cooling. Each heat-treated sample was examined for their microstructures and Vickers micro-hardness, and subjected to the X-ray diffraction for the phase identification. Using potentiostatic polarization method, each heat-treated sample was corrosion-tested in 37 degrees C 0.9% NaCl solution to estimate its corrosion rate. It was found that simulated sensitization showed an adverse influence on both steels, indicating that corrosion rates increased by increasing the sensitization temperatures.

Electrical Conductivity Response of Poly(Phenylene-vinylene)/Zeolite Composites Exposed to Ammonium Nitrate

PubMed Central

Kamonsawas, Jirarat; Sirivat, Anuvat; Niamlang, Sumonman; Hormnirun, Pimpa; Prissanaroon-Ouajai, Walaiporn

2010-01-01

Poly(p-phenylenevinylene) (PPV) was chemically synthesized via the polymerization of p-xylene-bis(tetrahydrothiophenium chloride) monomer and doped with H2SO4. To improve the electrical conductivity sensitivity of the conductive polymer, Zeolites Y (Si/Al = 5.1, 30, 60, 80) were added into the conductive polymer matrix. All composite samples show definite positive responses towards NH4NO3. The electrical conductivity sensitivities of the composite sensors increase linearly with increasing Si/Al ratio: with values of 0.201, 1.37, 2.80 and 3.18, respectively. The interactions between NH4NO3 molecules and the PPV/zeolite composites with respect to the electrical conductivity sensitivity were investigated through the infrared spectroscopy. PMID:22219677

Atom-Based Sensing of Weak Radio Frequency Electric Fields Using Homodyne Readout

PubMed Central

Kumar, Santosh; Fan, Haoquan; Kübler, Harald; Sheng, Jiteng; Shaffer, James P.

2017-01-01

We utilize a homodyne detection technique to achieve a new sensitivity limit for atom-based, absolute radio-frequency electric field sensing of 5 μV cm−1 Hz−1/2. A Mach-Zehnder interferometer is used for the homodyne detection. With the increased sensitivity, we investigate the dominant dephasing mechanisms that affect the performance of the sensor. In particular, we present data on power broadening, collisional broadening and transit time broadening. Our results are compared to density matrix calculations. We show that photon shot noise in the signal readout is currently a limiting factor. We suggest that new approaches with superior readout with respect to photon shot noise are needed to increase the sensitivity further. PMID:28218308

Sex-Related Differences in the Sensitivity to Carcinogenic Effect of Urethane on the Lungs in Mice Are Reversed after Neonatal Androgenization.

PubMed

Morozkova, T S; Kaledin, V I

2015-10-01

Experiments on male and female CC57BR/Mv mice differing by the sensitivity to carcinogenic effect of urethane on the lungs showed that castration 1 week before carcinogen challenge reduced the number of lung adenomas caused by it in males and somewhat increased the number of tumors in females. Exogenous testosterone after urethane injection caused virtually no changes in urethane effect in males and females. By contrast, elevation of testosterone concentrations in newborn male and female mice by injections or its decrease in feminized males receiving sodium glutamate during the neonatal period reduced the sensitivity to the carcinogenic effect of urethane in adult males and to its increase in females.

High-Sensitivity and Low-Hysteresis Porous MIM-Type Capacitive Humidity Sensor Using Functional Polymer Mixed with TiO2 Microparticles

PubMed Central

Liu, Ming-Qing; Wang, Cong; Kim, Nam-Young

2017-01-01

In this study, a high-sensitivity and low-hysteresis porous metal–insulator–metal-type capacitive humidity sensor is investigated using a functional polymer mixed with TiO2 microparticles. The humidity sensor consists of an optimally designed porous top electrode, a functional polymer humidity sensitive layer, a bottom electrode, and a glass substrate. The porous top electrode is designed to increase the contact area between the sensing layer and water vapor, leading to high sensitivity and quick response time. The functional polymer mixed with TiO2 microparticles shows excellent hysteresis under a wide humidity-sensing range with good long-term stability. The results show that as the relative humidity ranges from 10% RH to 90% RH, the proposed humidity sensor achieves a high sensitivity of 0.85 pF/% RH and a fast response time of less than 35 s. Furthermore, the sensor shows an ultra-low hysteresis of 0.95% RH at 60% RH, a good temperature dependence, and a stable capacitance value with a maximum of 0.17% RH drift during 120 h of continuous test. PMID:28157167

[Sensitivity and specificity of the breast screening program in the Isere region based on positive results between 1991 and 1999].

PubMed

Garnier, A; Poncet, F; Billette De Villemeur, A; Exbrayat, C; Bon, M F; Chevalier, A; Salicru, B; Tournegros, J M

2009-06-01

The screening program guidelines specify that the call back rate of women for additional imaging (positive mammogram) should not exceed 7% at initial screening, and 5% at subsequent screening. Materials and methods. Results in the Isere region (12%) have prompted a review of the correlation between the call back rate and indicators of quality (detection rate, sensitivity, specificity, positive predictive value) for the radiologists providing interpretations during that time period. Three groups of radiologists were identified: the group with call back rate of 10% achieved the best results (sensitivity: 92%, detection rate: 0.53%, specificity: 90%). The group with lowest call back rate (7.7%) showed insufficient sensitivity (58%). The last group with call back rate of 18.3%, showed no improvement in sensitivity (82%) and detection rate (0.53%), but showed reduced specificity (82%). The protocol update in 2001 does not resolve this problematic situation and national results continue to demonstrate a high percentage of positive screening mammograms. A significant increase in the number of positive screening examinations compared to recommended guidelines is not advantageous and leads to an overall decrease in the quality of the screening.

Food odors trigger an endocrine response that affects food ingestion and metabolism.

PubMed

Lushchak, Oleh V; Carlsson, Mikael A; Nässel, Dick R

2015-08-01

Food odors stimulate appetite and innate food-seeking behavior in hungry animals. The smell of food also induces salivation and release of gastric acid and insulin. Conversely, sustained odor exposure may induce satiation. We demonstrate novel effects of food odors on food ingestion, metabolism and endocrine signaling in Drosophila melanogaster. Acute exposure to attractive vinegar odor triggers a rapid and transient increase in circulating glucose, and a rapid upregulation of genes encoding the glucagon-like hormone adipokinetic hormone (AKH), four insulin-like peptides (DILPs) and some target genes in peripheral tissues. Sustained exposure to food odors, however, decreases food intake. Hunger-induced strengthening of synaptic signaling from olfactory sensory neurons (OSNs) to brain neurons increases food-seeking behavior, and conversely fed flies display reduced food odor sensitivity and feeding. We show that increasing the strength of OSN signaling chronically by genetic manipulation of local peptide neuromodulation reduces feeding, elevates carbohydrates and diminishes lipids. Furthermore, constitutively strengthened odor sensitivity altered gene transcripts for AKH, DILPs and some of their targets. Thus, we show that food odor can induce a transient anticipatory endocrine response, and that boosted sensitivity to this odor affects food intake, as well as metabolism and hormonal signaling.

Time course of the response of carbohydrate metabolism to unloading of the soleus

NASA Technical Reports Server (NTRS)

Henriksen, Erik J.; Tischler, Marc E.

1988-01-01

The time course of the response of carbohydrate metabolism to unloading was studied in the soleus muscle of rats subjected to tail-cast suspension. In the fresh soleus, 12 hours of unloading led to higher concentrations of glycogen and lower activity ratios of both glycogen synthase and glycogen phosphorylase. These changes were still evident on day three. Thereafter, the increased glycogen concentration apparently diminished the activity ratio of glycogen synthase, leading to a subsequent fall in the total glycogen content after day one. After 24 hours of unloading, when no significant atrophy was detectable, there was no differential response to insulin for in vitro glucose metabolism. On day three, the soleus atrophied significantly and displayed a greater sensitivity to insulin for most of these parameters compared to the weight-bearing control muscle. However, insulin sensitivity for glycogen synthesis was unchanged. These results showed that the increased sensitivity to insulin of the unloaded soleus is associated with the degree of muscle atrophy, likely due to an increased insulin binding capacity relative to muscle mass. This study also showed that insulin regulation of glucose uptake and of glycogen synthesis is affected differentially in the unloaded soleus muscle.

Estimating price elasticities when there is smuggling: the sensitivity of smoking to price in Canada.

PubMed

Gruber, Jonathan; Sen, Anindya; Stabile, Mark

2003-09-01

A central parameter for evaluating tax policies is the price elasticity of demand for cigarettes. But in many countries this parameter is difficult to estimate reliably due to widespread smuggling, which significantly biases estimates using legal sales data. An excellent example is Canada, where widespread smuggling in the early 1990s, in response to large tax increases, biases upwards the response of legal cigarette sales to price. We surmount this problem through two approaches: excluding the provinces and years where smuggling was greatest; and using household level expenditure data on smoking. These two approaches yield a tightly estimated elasticity in the range of -0.45 to -0.47. We also show that the sensitivity of smoking to price is much larger among lower income Canadians. In the context of recent behavioral models of smoking, whereby higher taxes reduce unwanted smoking among price sensitive populations, this finding suggests that cigarette taxes may not be as regressive as previously suggested. Finally, we show that price increases on cigarettes do not increase, and may actually decrease, consumption of alcohol; as a result, smuggling of cigarettes may have raised consumption of alcohol as well.

Mothers with depression, anxiety or eating disorders: outcomes on their children and the role of paternal psychological profiles.

PubMed

Cimino, Silvia; Cerniglia, Luca; Paciello, Marinella

2015-04-01

The present paper aims to longitudinally assess the emotional functioning of children of mothers with depression, anxiety, or eating disorders and of mothers with no psychological disorders and to evaluate the possible mediating role of fathers' psychological profiles on children's internalizing/externalizing functioning using SCID I, SCL-90/R and CBCL/1½-5. The results showed maternal psychopathology to be strongly related to children's maladaptive profiles. Children of mothers with depression and anxiety showed higher internalizing scores than children of other groups. These scores increased from T1 to T2. Children of mothers with eating disorders showed higher and increasing externalizing scores than children of other groups. The data showed that fathers' interpersonal sensitivity, depression, anxiety and psychoticism significantly predicted internalizing problems of the children. Moreover, interpersonal sensitivity and psychoticism significantly predicted externalizing problems. Our results confirmed the impact of maternal psychopathology on maladaptive outcomes in their children, which suggests the importance of considering paternal psychological profiles.

The phosphoenolpyruvate:sugar phosphotransferase system is involved in sensitivity to the glucosylated bacteriocin sublancin.

PubMed

Garcia De Gonzalo, C V; Denham, E L; Mars, R A T; Stülke, J; van der Donk, W A; van Dijl, J M

2015-11-01

The mode of action of a group of glycosylated antimicrobial peptides known as glycocins remains to be elucidated. In the current study of one glycocin, sublancin, we identified the phosphoenolpyruvate:sugar phosphotransferase system (PTS) of Bacillus species as a key player in bacterial sensitivity. Sublancin kills several Gram-positive bacteria, such as Bacillus species and Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). Unlike other classes of bacteriocins for which the PTS is involved in their mechanism of action, we show that the addition of PTS-requiring sugars leads to increased resistance rather than increased sensitivity, suggesting that sublancin has a distinct mechanism of action. Collectively, our present mutagenesis and genomic studies demonstrate that the histidine-containing phosphocarrier protein (HPr) and domain A of enzyme II (PtsG) in particular are critical determinants for bacterial sensitivity to sublancin. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Parasympathetic activation by pyridostigmine on chemoreflex sensitivity in heart-failure rats.

PubMed

Sabino, João Paulo J; da Silva, Carlos Alberto Aguiar; Giusti, Humberto; Glass, Mogens Lesner; Salgado, Helio C; Fazan, Rubens

2013-12-01

We evaluated the effects of parasympathetic activation by pyridostigmine (PYR) on chemoreflex sensitivity in a rat model of heart failure (HF rats). HF rats demonstrated higher pulmonary ventilation (PV), which was not affected by PYR. When HF and control rats treated or untreated with PYR were exposed to 15% O2, all groups exhibited prompt increases in respiratory frequency (RF), tidal volume (TV) and PV. When HF rats were exposed to 10% O2 they showed greater PV response which was prevented by PYR. The hypercapnia triggered by either 5% CO2 or 10% CO2 promoted greater RF and PV responses in HF rats. PYR blunted the RF response in HF rats but did not affect the PV response. In conclusion, PYR prevented increased peripheral chemoreflex sensitivity, partially blunted central chemoreflex sensitivity and did not affect basal PV in HF rats. © 2013.

Background odour induces adaptation and sensitization of olfactory receptors in the antennae of houseflies.

PubMed

Kelling, F J; Ialenti, F; Den Otter, C J

2002-06-01

The presence of background odour was found to have a small but significant effect on the sensitivity of the antennal olfactory system of houseflies, Musca domestica Linnaeus (Diptera: Muscidae), to new pulses of odour. We show that cross-adaptation and cross-sensitization between a background odour of (+/-)-1-octen-3-ol and pulses of (+/-)-1-octen-3-ol, 2-pentanone and R-(+)-limonene can occur, confirming that olfactory receptor cells are sensitive to different odours. Background odour can increase the responses to low concentration odour pulses and decrease the responses to higher concentration odour pulses. It is suggested that background odour has a larger effect on olfactory receptor cells that respond with a tonic increase of spike frequency, giving information about the level of odour concentration, i.e. the 'static' environment. Cells that respond in a phasic way only provide information on the dynamics of the olfactory environment.

SAW Humidity Sensor Sensitivity Enhancement via Electrospraying of Silver Nanowires

PubMed Central

Sayar Irani, Farid; Tunaboylu, Bahadir

2016-01-01

In this research, we investigated the influence of the surface coatings of silver nanowires on the sensitivity of surface acoustic wave (SAW) humidity sensors. Silver nanowires, with poly(vinylpyrrolidone) (PVP), which is a hydrophilic capping agent, were chemically synthesized, with an average length of 15 µm and an average diameter of 60 nm. Humidity sensors, with 433 MHz frequency dual-port resonator Rayleigh-SAW devices, were coated by silver nanowires (AgNWs) using the electrospray coating method. It was demonstrated that increasing thickness of coated AgNW on the surfaces of SAW devices results in increased sensitivity. The highest frequency shift (262 kHz) in these SAW devices was obtained with an injection of 0.5 mL of the AgNW solution with a concentration of 0.5 mg/mL at an injection rate of 1 mL/h. It also showed the highest humidity sensitivity among the other prepared SAW devices. PMID:27916870

The Clinical Impact of Bet v 6 in Birch Pollen-Sensitized Patients.

PubMed

Gellrich, Donata; Eder, Katharina; San Nicoló, Marion; Berghaus, Alexander; Gröger, Moritz

2017-01-01

Bet v 6, a minor birch pollen allergen, is commercially available for allergen-specific IgE antibody testing. However, there is hardly any literature on the clinical impact of Bet v 6. The aim of the present study was to analyze if testing specific IgE against Bet v 6 can add valuable benefit to the standard diagnostics of birch pollen-sensitized patients, especially in patients with unknown sensitization-eliciting allergens. Birch pollen-sensitized patients with missing IgE reactivity against Bet v 1, 2, and 4 were tested for specific IgE antibodies against Bet v 6. For comparison, an equal number of randomly selected patients with birch pollen sensitization, regardless of their individual sensitization patterns, were tested for specific anti-Bet v 6. Of 57 cases with missing reactivity against the standard birch pollen allergens, 2 patients were positive for Bet v 6. In the representative sample, 3 patients showed specific IgE against Bet v 6 - resulting in a total prevalence of 5%. None of the Bet v 6-positive patients showed allergic symptoms after exposure to birch pollen or an oral allergy syndrome. An increased prevalence of asthma and a higher degree of sensitization were the only distinctive clinical features in Bet v 6-positive patients. Among birch pollen-sensitized patients, the prevalence of specific IgE against Bet v 6 is low. Further, sensitization to Bet v 6, which shows characteristics of a panallergen, remains clinically silent. Therefore, determination of anti-Bet v 6 is not considered useful in the clinical routine. © 2017 S. Karger AG, Basel.

Inhibitory masking controls the threshold sensitivity of retinal ganglion cells

PubMed Central

Pan, Feng; Toychiev, Abduqodir; Zhang, Yi; Atlasz, Tamas; Ramakrishnan, Hariharasubramanian; Roy, Kaushambi; Völgyi, Béla; Akopian, Abram

2016-01-01

Key points Retinal ganglion cells (RGCs) in dark‐adapted retinas show a range of threshold sensitivities spanning ∼3 log units of illuminance.Here, we show that the different threshold sensitivities of RGCs reflect an inhibitory mechanism that masks inputs from certain rod pathways.The masking inhibition is subserved by GABAC receptors, probably on bipolar cell axon terminals.The GABAergic masking inhibition appears independent of dopaminergic circuitry that has been shown also to affect RGC sensitivity.The results indicate a novel mechanism whereby inhibition controls the sensitivity of different cohorts of RGCs. This can limit and thereby ensure that appropriate signals are carried centrally in scotopic conditions when sensitivity rather than acuity is crucial. Abstract The responses of rod photoreceptors, which subserve dim light vision, are carried through the retina by three independent pathways. These pathways carry signals with largely different sensitivities. Retinal ganglion cells (RGCs), the output neurons of the retina, show a wide range of sensitivities in the same dark‐adapted conditions, suggesting a divergence of the rod pathways. However, this organization is not supported by the known synaptic morphology of the retina. Here, we tested an alternative idea that the rod pathways converge onto single RGCs, but inhibitory circuits selectively mask signals so that one pathway predominates. Indeed, we found that application of GABA receptor blockers increased the sensitivity of most RGCs by unmasking rod signals, which were suppressed. Our results indicate that inhibition controls the threshold responses of RGCs under dim ambient light. This mechanism can ensure that appropriate signals cross the bottleneck of the optic nerve in changing stimulus conditions. PMID:27350405

[Application of Fourier amplitude sensitivity test in Chinese healthy volunteer population pharmacokinetic model of tacrolimus].

PubMed

Guan, Zheng; Zhang, Guan-min; Ma, Ping; Liu, Li-hong; Zhou, Tian-yan; Lu, Wei

2010-07-01

In this study, we evaluated the influence of different variance from each of the parameters on the output of tacrolimus population pharmacokinetic (PopPK) model in Chinese healthy volunteers, using Fourier amplitude sensitivity test (FAST). Besides, we estimated the index of sensitivity within whole course of blood sampling, designed different sampling times, and evaluated the quality of parameters' and the efficiency of prediction. It was observed that besides CL1/F, the index of sensitivity for all of the other four parameters (V1/F, V2/F, CL2/F and k(a)) in tacrolimus PopPK model showed relatively high level and changed fast with the time passing. With the increase of the variance of k(a), its indices of sensitivity increased obviously, associated with significant decrease in sensitivity index for the other parameters, and obvious change in peak time as well. According to the simulation of NONMEM and the comparison among different fitting results, we found that the sampling time points designed according to FAST surpassed the other time points. It suggests that FAST can access the sensitivities of model parameters effectively, and assist the design of clinical sampling times and the construction of PopPK model.

Low temperature annealed amorphous indium gallium zinc oxide (a-IGZO) as a pH sensitive layer for applications in field effect based sensors

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

Kumar, Narendra; Samtel Centre for Display Technologies, Indian Institute of Technology Kanpur, Kanpur-208016; Kumar, Jitendra

The use of a-IGZO instead of the conventional high-k dielectrics as a pH sensitive layer could lead to the simplification of fabrication steps of field effect based devices. In this work, the pH sensitivities of a-IGZO films directly deposited over a SiO{sub 2}/Si surface were studied utilizing electrolyte-insulator-semiconductor (EIS) structures. Annealing of the films was found to affect the sensitivity of the devices and the device with the film annealed at 400 {sup o}C in N{sub 2} ambience showed the better sensitivity, which reduced with further increase in the annealing temperature to 500 {sup o}C. The increased pH sensitivity withmore » the film annealed at 400 {sup o}C in N{sub 2} gas was attributed to the enhanced lattice oxygen ions (based on the XPS data) and improved C-V characteristics, while the decrease in sensitivity at an increased annealing temperature of 500 {sup o}C was attributed to defects in the films as well as the induced traps at the IGZO/SiO{sub 2} interface based on the stretched accumulation and the peak in the inversion region of C-V curves. This study could help to develop a sensor where the material (a-IGZO here) used as the active layer in a thin film transistors (TFTs) possibly could also be used as the pH sensitive layer without affecting the TFT characteristics, and thus obviating the need of high-K dielectrics for sensitivity enhancement.« less

Determination of ABO blood grouping and Rhesus factor from tooth material

PubMed Central

Kumar, Pooja Vijay; Vanishree, M; Anila, K; Hunasgi, Santosh; Suryadevra, Sri Sujan; Kardalkar, Swetha

2016-01-01

Objective: The aim of the study was to determine blood groups and Rhesus factor from dentin and pulp using absorption-elution (AE) technique in different time periods at 0, 3, 6, 9 and 12 months, respectively. Materials and Methods: A total of 150 cases, 30 patients each at 0, 3, 6, 9 and 12 months were included in the study. The samples consisted of males and females with age ranging 13–60 years. Patient's blood group was checked and was considered as “control.” The dentin and pulp of extracted teeth were tested for the presence of ABO/Rh antigen, at respective time periods by AE technique. Statistical Analysis: Data were analyzed in proportion. For comparison, Chi-square test or Fisher's exact test was used for the small sample. Results: Blood group antigens of ABO and Rh factor were detected in dentin and pulp up to 12 months. For both ABO and Rh factor, dentin and pulp showed 100% sensitivity for the samples tested at 0 month and showed a gradual decrease in the sensitivity as time period increased. The sensitivity of pulp was better than dentin for both the blood grouping systems and ABO blood group antigens were better detected than Rh antigens. Conclusion: In dentin and pulp, the antigens of ABO and Rh factor were detected up to 12 months but showed a progressive decrease in the antigenicity as the time period increased. When compared the results obtained of dentin and pulp in ABO and Rh factor grouping showed similar results with no statistical significance. The sensitivity of ABO blood grouping was better than Rh factor blood grouping and showed a statistically significant result. PMID:27721625

Eating high fat chow enhances the locomotor-stimulating effects of cocaine in adolescent and adult female rats.

PubMed

Baladi, Michelle G; Koek, Wouter; Aumann, Megan; Velasco, Fortino; France, Charles P

2012-08-01

Dopamine systems vary through development in a manner that can impact drugs acting on those systems. Dietary factors can also impact the effects of drugs acting on dopamine systems. This study examined whether eating high fat chow alters locomotor effects of cocaine (1-56 mg/kg) in adolescent and adult female rats. Cocaine was studied in rats (n = 6/group) with free access to standard (5.7% fat) or high fat (34.3%) chow or restricted access to high fat chow (body weight matched to rats eating standard chow). After 1 week of eating high fat chow (free or restricted access), sensitivity to cocaine was significantly increased in adolescent and adult rats, compared with rats eating standard chow. Sensitivity to cocaine was also increased in adolescent rats with restricted, but not free, access to high fat chow for 4 weeks. When adolescent and adult rats that previously ate high fat chow ate standard chow, sensitivity to cocaine returned to normal. In adolescent and adult female rats eating high fat chow, but not those eating standard chow, sensitivity to cocaine increased progressively over once weekly tests with cocaine (i.e., sensitization) in a manner that was not statistically different between adolescents and adults. These results show that eating high fat chow alters sensitivity of female rats to acutely administered cocaine and also facilitates the development of sensitization to cocaine. That the type of food consumed can increase drug effects might have relevance to vulnerability to abuse cocaine in the female population.

Indoor fungal diversity in primary schools may differently influence allergic sensitization and asthma in children.

PubMed

Cavaleiro Rufo, João; Madureira, Joana; Paciência, Inês; Aguiar, Lívia; Pereira, Cristiana; Silva, Diana; Padrão, Patrícia; Moreira, Pedro; Delgado, Luís; Annesi-Maesano, Isabella; Oliveira Fernandes, Eduardo; Teixeira, João Paulo; Moreira, André

2017-06-01

Childhood exposure to microbiologic agents may influence the development of allergic and respiratory diseases. Apart from home, children spend most of their time at school, which represents an environment of significant exposure to indoor air microbes. Therefore, we aimed to assess how the prevalence of allergic sensitization and asthma in schoolchildren is affected by microbiologic exposure within classrooms. Spirometry with bronchodilation, exhaled nitric oxide measurements and skin-prick tests data were retrieved from 858 children aged 8-10 years attending 71 classrooms in 20 primary schools. Air samples were collected in all classrooms using a single-stage microbiologic air impactor through agar plates. Gram-negative endotoxins were collected using flow control pumps and analysed by limulus amebocyte lysate assay. Diversity scores were established as the number of different fungal species found in each classroom. Classrooms with increased diversity scores showed a significantly lower prevalence of children with atopic sensitization, but not asthma. The risk of sensitization increased with increasing endotoxin exposure in classrooms. Similarly, significantly higher concentrations of Penicillium spp were found in classrooms with a higher number of children with atopic sensitization. Although no causal relationships could be established, exposure to higher fungal diversity was protective against allergic sensitization but this was not seen for asthma. In contrast, higher exposure to Gram-negative endotoxins and Penicillium spp in primary school's classrooms was associated with increasing odds of allergic sensitization in children. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Modelling in vivo creatine/phosphocreatine in vitro reveals divergent adaptations in human muscle mitochondrial respiratory control by ADP after acute and chronic exercise.

PubMed

Ydfors, Mia; Hughes, Meghan C; Laham, Robert; Schlattner, Uwe; Norrbom, Jessica; Perry, Christopher G R

2016-06-01

Mitochondrial respiratory sensitivity to ADP is thought to influence muscle fitness and is partly regulated by cytosolic-mitochondrial diffusion of ADP or phosphate shuttling via creatine/phosphocreatine (Cr/PCr) through mitochondrial creatine kinase (mtCK). Previous measurements of respiration in vitro with Cr (saturate mtCK) or without (ADP/ATP diffusion) show mixed responses of ADP sensitivity following acute exercise vs. less sensitivity after chronic exercise. In human muscle, modelling in vivo 'exercising' [Cr:PCr] during in vitro assessments revealed novel responses to exercise that differ from detections with or without Cr (±Cr). Acute exercise increased ADP sensitivity when measured without Cr but had no effect ±Cr or with +Cr:PCr, whereas chronic exercise increased sensitivity ±Cr but lowered sensitivity with +Cr:PCr despite increased markers of mitochondrial oxidative capacity. Controlling in vivo conditions during in vitro respiratory assessments reveals responses to exercise that differ from typical ±Cr comparisons and challenges our understanding of how exercise improves metabolic control in human muscle. Mitochondrial respiratory control by ADP (Kmapp ) is viewed as a critical regulator of muscle energy homeostasis. However, acute exercise increases, decreases or has no effect on Kmapp in human muscle, whereas chronic exercise surprisingly decreases sensitivity despite greater mitochondrial content. We hypothesized that modelling in vivo mitochondrial creatine kinase (mtCK)-dependent phosphate-shuttling conditions in vitro would reveal increased sensitivity (lower Kmapp ) after acute and chronic exercise. The Kmapp was determined in vitro with 20 mm Cr (+Cr), 0 mm Cr (-Cr) or 'in vivo exercising' 20 mm Cr/2.4 mm PCr (Cr:PCr) on vastus lateralis biopsies sampled from 11 men before, immediately after and 3 h after exercise on the first, fifth and ninth sessions over 3 weeks. Dynamic responses to acute exercise occurred throughout training, whereby the first session did not change Kmapp with in vivo Cr:PCr despite increases in -Cr. The fifth session decreased sensitivity with Cr:PCr or +Cr despite no change in -Cr. Chronic exercise increased sensitivity ±Cr in association with increased electron transport chain content (+33-62% complexes I-V), supporting classic proposals that link increased sensitivity to oxidative capacity. However, in vivo Cr:PCr reveals a perplexing decreased sensitivity, contrasting the increases seen ±Cr. Functional responses occurred without changes in fibre type or proteins regulating mitochondrial-cytosolic energy exchange (mtCK, VDAC and ANT). Despite the dynamic responses seen with ±Cr, modelling in vivo phosphate-shuttling conditions in vitro reveals that ADP sensitivity is unchanged after high-intensity exercise and is decreased after training. These findings challenge our understanding of how exercise regulates skeletal muscle energy homeostasis. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Thermal and chemical treatment of polymer optical fiber Bragg grating sensors for enhanced mechanical sensitivity

NASA Astrophysics Data System (ADS)

Pospori, A.; Marques, C. A. F.; Sáez-Rodríguez, D.; Nielsen, K.; Bang, O.; Webb, D. J.

2017-07-01

An investigation of the thermal annealing effects on the strain, stress, and force sensitivities of polymer optical fiber Bragg grating sensors is performed. We demonstrate for the first time that the fiber annealing can enhance both stress and force sensitivities of Bragg grating sensors, with the possible cause being the molecular relaxation of the polymer when fiber is raised above the β -transition temperature. A simple, cost-effective, but well controlled method for fiber annealing is also presented in this work. In addition, the effects of chemical etching on the strain, stress, and force sensitivities have been investigated. Results show that fiber etching too can increase the force sensitivity, and it can also affect the strain and stress sensitivities of the Bragg grating sensors.

Mental Imagery Training Increases Wanting of Rewards and Reward Sensitivity and Reduces Depressive Symptoms.

PubMed

Linke, Julia; Wessa, Michèle

2017-09-01

High reward sensitivity and wanting of rewarding stimuli help to identify and motivate repetition of pleasant activities. This behavioral activation is thought to increase positive emotions. Therefore, both mechanisms are highly relevant for resilience against depressive symptoms. Yet, these mechanisms have not been targeted by psychotherapeutic interventions. In the present study, we tested a mental imagery training comprising eight 10-minute sessions every second day and delivered via the Internet to healthy volunteers (N = 30, 21 female, mean age of 23.8 years, Caucasian) who were preselected for low reward sensitivity. Participants were paired according to age, sex, reward sensitivity, and mental imagery ability. Then, members of each pair were randomly assigned to either the intervention or wait condition. Ratings of wanting and response bias toward probabilistic reward cues (Probabilistic Reward Task) served as primary outcomes. We further tested whether training effects extended to approach behavior (Approach Avoidance Task) and depressive symptoms (Beck Depression Inventory). The intervention led to an increase in wanting (p < .001, η 2 p = .45) and reward sensitivity (p = .004, η 2 p = .27). Further, the training group displayed faster approach toward positive edibles and activities (p = .025, η 2 p = .18) and reductions in depressive symptoms (p = .028, η 2 p = .16). Results extend existing literature by showing that mental imagery training can increase wanting of rewarding stimuli and reward sensitivity. Further, the training appears to reduce depressive symptoms and thus may foster the successful implementation of exsiting treatments for depression such as behavioral activation and could also increase resilience against depressive symptoms. Copyright © 2017. Published by Elsevier Ltd.

Neural sensitivity to statistical regularities as a fundamental biological process that underlies auditory learning: the role of musical practice.

PubMed

François, Clément; Schön, Daniele

2014-02-01

There is increasing evidence that humans and other nonhuman mammals are sensitive to the statistical structure of auditory input. Indeed, neural sensitivity to statistical regularities seems to be a fundamental biological property underlying auditory learning. In the case of speech, statistical regularities play a crucial role in the acquisition of several linguistic features, from phonotactic to more complex rules such as morphosyntactic rules. Interestingly, a similar sensitivity has been shown with non-speech streams: sequences of sounds changing in frequency or timbre can be segmented on the sole basis of conditional probabilities between adjacent sounds. We recently ran a set of cross-sectional and longitudinal experiments showing that merging music and speech information in song facilitates stream segmentation and, further, that musical practice enhances sensitivity to statistical regularities in speech at both neural and behavioral levels. Based on recent findings showing the involvement of a fronto-temporal network in speech segmentation, we defend the idea that enhanced auditory learning observed in musicians originates via at least three distinct pathways: enhanced low-level auditory processing, enhanced phono-articulatory mapping via the left Inferior Frontal Gyrus and Pre-Motor cortex and increased functional connectivity within the audio-motor network. Finally, we discuss how these data predict a beneficial use of music for optimizing speech acquisition in both normal and impaired populations. Copyright © 2013 Elsevier B.V. All rights reserved.

Variation in hearing within a wild population of beluga whales (Delphinapterus leucas).

PubMed

Mooney, T Aran; Castellote, Manuel; Quakenbush, Lori; Hobbs, Roderick; Gaglione, Eric; Goertz, Caroline

2018-05-08

Documenting hearing abilities is vital to understanding a species' acoustic ecology and for predicting the impacts of increasing anthropogenic noise. Cetaceans use sound for essential biological functions such as foraging, navigation and communication; hearing is considered to be their primary sensory modality. Yet, we know little regarding the hearing of most, if not all, cetacean populations, which limits our understanding of their sensory ecology, population level variability and the potential impacts of increasing anthropogenic noise. We obtained audiograms (5.6-150 kHz) of 26 wild beluga whales to measure hearing thresholds during capture-release events in Bristol Bay, AK, USA, using auditory evoked potential methods. The goal was to establish the baseline population audiogram, incidences of hearing loss and general variability in wild beluga whales. In general, belugas showed sensitive hearing with low thresholds (<80 dB) from 16 to 100 kHz, and most individuals (76%) responded to at least 120 kHz. Despite belugas often showing sensitive hearing, thresholds were usually above or approached the low ambient noise levels measured in the area, suggesting that a quiet environment may be associated with hearing sensitivity and that hearing thresholds in the most sensitive animals may have been masked. Although this is just one wild population, the success of the method suggests that it should be applied to other populations and species to better assess potential differences. Bristol Bay beluga audiograms showed substantial (30-70 dB) variation among individuals; this variation increased at higher frequencies. Differences among individual belugas reflect that testing multiple individuals of a population is necessary to best describe maximum sensitivity and population variance. The results of this study quadruple the number of individual beluga whales for which audiograms have been conducted and provide the first auditory data for a population of healthy wild odontocetes. © 2018. Published by The Company of Biologists Ltd.

The association of noise sensitivity with music listening, training, and aptitude.

PubMed

Kliuchko, Marina; Heinonen-Guzejev, Marja; Monacis, Lucia; Gold, Benjamin P; Heikkilä, Kauko V; Spinosa, Vittoria; Tervaniemi, Mari; Brattico, Elvira

2015-01-01

After intensive, long-term musical training, the auditory system of a musician is specifically tuned to perceive musical sounds. We wished to find out whether a musician's auditory system also develops increased sensitivity to any sound of everyday life, experiencing them as noise. For this purpose, an online survey, including questionnaires on noise sensitivity, musical background, and listening tests for assessing musical aptitude, was administered to 197 participants in Finland and Italy. Subjective noise sensitivity (assessed with the Weinstein's Noise Sensitivity Scale) was analyzed for associations with musicianship, musical aptitude, weekly time spent listening to music, and the importance of music in each person's life (or music importance). Subjects were divided into three groups according to their musical expertise: Nonmusicians (N = 103), amateur musicians (N = 44), and professional musicians (N = 50). The results showed that noise sensitivity did not depend on musical expertise or performance on musicality tests or the amount of active (attentive) listening to music. In contrast, it was associated with daily passive listening to music, so that individuals with higher noise sensitivity spent less time in passive (background) listening to music than those with lower sensitivity to noise. Furthermore, noise-sensitive respondents rated music as less important in their life than did individuals with lower sensitivity to noise. The results demonstrate that the special sensitivity of the auditory system derived from musical training does not lead to increased irritability from unwanted sounds. However, the disposition to tolerate contingent musical backgrounds in everyday life depends on the individual's noise sensitivity.

[Sensitivity and specificity of flicker perimetry with Pulsar. Comparison with achromatic (white-on-white) perimetry in glaucoma patients].

PubMed

Göbel, K; Erb, C

2013-02-01

The early detection of functional glaucoma damage plays an increasingly more central role in the diagnosis and treatment of glaucoma disease. Using selective perimetry detection of early glaucomatous defects is more likely and one of these methods is flicker perimetry with Pulsar. Flicker perimetry is used to analyze the temporal visual function in combination with spatial resolution and contrast sensitivity as opposed to standard automated perimetry which measures the differential light sensitivity with a non-specific stimulus. This study showed a higher sensitivity and specificity of Pulsar perimetry in comparison to achromatic perimetry in glaucoma patients.

Inflammatory responses to psychological stress in fatigued breast cancer survivors: relationship to glucocorticoids.

PubMed

Bower, Julienne E; Ganz, Patricia A; Aziz, Najib; Olmstead, Richard; Irwin, Michael R; Cole, Steve W

2007-03-01

Fatigue is a common problem following cancer treatment and our previous studies suggest that a chronic inflammatory process might contribute to cancer-related fatigue. However, immune responses to challenge have not yet been evaluated among individuals with cancer-related fatigue, and it is not known what mechanisms drive increased levels of inflammatory markers in fatigued cancer survivors. We have previously reported that fatigued breast cancer survivors show a blunted cortisol response to an experimental psychological stressor. In this report, we focus on inflammatory responses to this stressor and their relationship to circulating glucocorticoids and cellular sensitivity to glucocorticoid inhibition. Relative to non-fatigued control survivors, participants experiencing persistent fatigue showed significantly greater increases in LPS-stimulated production of IL-1beta and IL-6 following the stressor (Group x Time interaction: p<.05). Fatigued participants did not show any difference in cellular sensitivity to cortisol inhibition of cytokine production, but they did show significantly less salivary cortisol increase in the aftermath of the stressor. Moreover, blunted cortisol responses were associated with significantly increased production of IL-6 in response to LPS stimulation (p<.05). These data provide further evidence of enhanced inflammatory processes in fatigued breast cancer survivors and suggest that these processes may stem in part from decreased glucocorticoid response to stress.

Analysis of the optical characteristics of adipose tissue in vitro sensitized by indocyanine green and exposed to IR-laser irradiation

NASA Astrophysics Data System (ADS)

Yanina, I. Yu.; Doubrovski, V. A.; Tuchin, V. V.

2015-03-01

The effect of IR-laser irradiation on adipose tissue sensitized by indocyanine green is studied in vitro. Experiments and statistical analysis are used to show that wavelength-selective irradiation leads to an increase in the homogeneity of optical images of adipose cells with time. The transmission coefficient that is averaged over the image area weakly depends on the observation time. An increase in the homogeneity of images is interpreted as a result of immersion of optical inhomogeneities of tissue owing to the intracellular liquid that is released through the photochemically induced pores in cellular membranes. An increase in the optical homogeneity of the medium is compensated for by a decrease in the transmission coefficient of the sensitizer, which is manifested as a weak time dependence of the image-averaged transmittance of tissue.

Long-term alterations in vulnerability to addiction to drugs of abuse and in brain gene expression after early life ethanol exposure.

PubMed

Barbier, Estelle; Pierrefiche, Olivier; Vaudry, David; Vaudry, Hubert; Daoust, Martine; Naassila, Mickaël

2008-12-01

Exposure to ethanol early in life can have long-lasting implications on brain function and drug of abuse response later in life. The present study investigated in rats, the long-term consequences of pre- and postnatal (early life) ethanol exposure on drug consumption/reward and the molecular targets potentially associated with these behavioral alterations. Since a relationship has been demonstrated between heightened drugs intake and susceptibility to drugs-induced locomotor activity/sensitization, anxiolysis, we tested these behavioral responses, depending on the drug, in control and early life ethanol-exposed animals. Our results show that progeny exposed to early life ethanol displayed increased consumption of ethanol solutions and increased sensitivity to cocaine rewarding effects assessed in the conditioned place preference test. Offspring exposed to ethanol were more sensitive to the anxiolytic effect of ethanol and the increased sensitivity could, at least in part, explain the alteration in the consumption of ethanol for its anxiolytic effects. In addition, the sensitivity to hypothermic effects of ethanol and ethanol metabolism were not altered by early life ethanol exposure. The sensitization to cocaine (20 mg/kg) and to amphetamine (1.2 mg/kg) was increased after early life ethanol exposure and, could partly explain, an increase in the rewarding properties of psychostimulants. Gene expression analysis revealed that expression of a large number of genes was altered in brain regions involved in the reinforcing effects of drugs of abuse. Dopaminergic receptors and transporter binding sites were also down-regulated in the striatum of ethanol-exposed offspring. Such long-term neurochemical alterations in transmitter systems and in the behavioral responses to ethanol and other drugs of abuse may confer an increased liability for addiction in exposed offspring.

Stress vulnerability and the effects of moderate daily stress on sleep polysomnography and subjective sleepiness.

PubMed

Petersen, Helena; Kecklund, Göran; D'Onofrio, Paolo; Nilsson, Jens; Åkerstedt, Torbjörn

2013-02-01

The purpose of this study was to investigate if and how sleep physiology is affected by naturally occurring high work stress and identify individual differences in the response of sleep to stress. Probable upcoming stress levels were estimated through weekly web questionnaire ratings. Based on the modified FIRST-scale (Ford insomnia response to stress) participants were grouped into high (n = 9) or low (n = 19) sensitivity to stress related sleep disturbances (Drake et al., 2004). Sleep was recorded in 28 teachers with polysomnography, sleep diaries and actigraphs during one high stress and one low stress condition in the participants home. EEG showed a decrease in sleep efficiency during the high stress condition. Significant interactions between group and condition were seen for REM sleep, arousals and stage transitions. The sensitive group had an increase in arousals and stage transitions during the high stress condition and a decrease in REM, whereas the opposite was seen in the resilient group. Diary ratings during the high stress condition showed higher bedtime stress and lower ratings on the awakening index (insufficient sleep and difficulties awakening). Ratings also showed lower cognitive function and preoccupation with work thoughts in the evening. KSS ratings of sleepiness increased during stress for the sensitive group. Saliva samples of cortisol showed no effect of stress. It was concluded that moderate daily stress is associated with a moderate negative effect on sleep sleep efficiency and fragmentation. A slightly stronger effect was seen in the sensitive group. © 2012 European Sleep Research Society.

Pulmonary Stress Induced by Hyperthermia: Role of Airway Sensory Nerves

DTIC Science & Technology

2013-10-01

ABSTRACT Based upon the results obtained from these studies, we can draw the following conclusions: 1) Airway hyperresponsiveness developed in Ova ...hyperthermia in Ova -sensitized rats. The manuscript reporting the results obtained frim this study has been accepted for publication by the Journal of...to increasing airway temperature. Our results showed: 1) In Brown-Norway rats actively sensitized by ovalbumin ( Ova ), isocapnic hyperventilation with

Cocaine sensitization increases subthreshold activity in dopamine neurons from the ventral tegmental area.

PubMed

Arencibia-Albite, Francisco; Vázquez-Torres, Rafael; Jiménez-Rivera, Carlos A

2017-02-01

The progressive escalation of psychomotor responses that results from repeated cocaine administration is termed sensitization. This phenomenon alters the intrinsic properties of dopamine (DA) neurons from the ventral tegmental area (VTA), leading to enhanced dopaminergic transmission in the mesocorticolimbic network. The mechanisms underlying this augmented excitation are nonetheless poorly understood. DA neurons display the hyperpolarization-activated, nonselective cation current, dubbed I h We recently demonstrated that I h and membrane capacitance are substantially reduced in VTA DA cells from cocaine-sensitized rats. The present study shows that 7 days of cocaine withdrawal did not normalize I h and capacitance. In cells from cocaine-sensitized animals, the amplitude of excitatory synaptic potentials, at -70 mV, was ∼39% larger in contrast to controls. Raise and decay phases of the synaptic signal were faster under cocaine, a result associated with a reduced membrane time constant. Synaptic summation was paradoxically elevated by cocaine exposure, as it consisted of a significantly reduced summation indexed but a considerably increased depolarization. These effects are at least a consequence of the reduced capacitance. I h attenuation is unlikely to explain such observations, since at -70 mV, no statistical differences exist in I h or input resistance. The neuronal shrinkage associated with a diminished capacitance may help to understand two fundamental elements of drug addiction: incentive sensitization and negative emotional states. A reduced cell size may lead to substantial enhancement of cue-triggered bursting, which underlies drug craving and reward anticipation, whereas it could also result in DA depletion, as smaller neurons might express low levels of tyrosine hydroxylase. This work uses a new approach that directly extracts important biophysical parameters from alpha function-evoked synaptic potentials. Two of these parameters are the cell membrane capacitance (C m ) and rate at any time point of the synaptic waveform. The use of such methodology shows that cocaine sensitization reduces C m and increases the speed of synaptic signaling. Paradoxically, although synaptic potentials show a faster decay under cocaine their temporal summation is substantially elevated. Copyright © 2017 the American Physiological Society.

Fibromyalgia interacts with age to change the brain☆☆☆

PubMed Central

Ceko, Marta; Bushnell, M. Catherine; Fitzcharles, Mary-Ann; Schweinhardt, Petra

2013-01-01

Although brain plasticity in the form of gray matter increases and decreases has been observed in chronic pain, factors determining the patterns of directionality are largely unknown. Here we tested the hypothesis that fibromyalgia interacts with age to produce distinct patterns of gray matter differences, specifically increases in younger and decreases in older patients, when compared to age-matched healthy controls. The relative contribution of pain duration was also investigated. Regional gray matter was measured in younger (n = 14, mean age 43, range 29–49) and older (n = 14; mean age 55, range 51–60) female fibromyalgia patients and matched controls using voxel-based morphometry and cortical thickness analysis of T1-weighted magnetic resonance images. To examine their functional significance, gray matter differences were compared with experimental pain sensitivity. Diffusion-tensor imaging was used to assess whether white matter changed in parallel with gray matter, and resting-state fMRI was acquired to examine whether pain-related gray matter changes are associated with altered functional connectivity. Older patients showed exclusively decreased gray matter, accompanied by compromised white matter integrity. In contrast, younger patients showed exclusively gray matter increases, namely in the basal ganglia and insula, which were independent of pain duration. Associated white matter changes in younger patients were compatible with gray matter hypertrophy. In both age groups, structural brain alterations were associated with experimental pain sensitivity, which was increased in older patients but normal in younger patients. Whereas more pronounced gray matter decreases in the posterior cingulate cortex were related to increased experimental pain sensitivity in older patients, insular gray matter increases in younger patients correlated with lower pain sensitivity, possibly indicating the recruitment of endogenous pain modulatory mechanisms. This is supported by the finding that the insula in younger patients showed functional decoupling from an important pain-processing region, the dorsal anterior cingulate cortex. These results suggest that brain structure and function shift from being adaptive in younger to being maladaptive in older patients, which might have important treatment implications. PMID:24273710

Sleep System Sensitization: Evidence for Changing Roles of Etiological Factors in Insomnia

PubMed Central

Kalmbach, David A.; Pillai, Vivek; Arnedt, J. Todd; Anderson, Jason R.; Drake, Christopher L.

2016-01-01

Objectives To test for sensitization of the sleep system in response to insomnia development and major life stress. In addition, to evaluate the impact on depression and anxiety associated with sleep system sensitization. Methods A longitudinal study with three annual assessments. The community-based sample included 262 adults with no history of insomnia or depression who developed insomnia 1 year after baseline (67.6% female; 44.0±13.4y). Measures included the Ford Insomnia Response to Stress Test to assess sleep reactivity, Quick Inventory of Depressive Symptomatology, and Beck Anxiety Inventory. Insomnia classification was based on DSM-IV criteria. Sleep system sensitization was operationally defined as significant increases in sleep reactivity. Results Sensitization of the sleep system was observed from baseline to insomnia onset at 1-y follow-up among insomniacs with low premorbid vulnerability (p<.001), resulting in 68.3% of these individuals re-classified as highly sleep reactive. Major life stress was associated with greater sleep system sensitization (p=.02). Results showed that sleep reactivity at 2-y follow-up remained elevated among those with low premorbid vulnerability, even after insomnia remission (p<.01). Finally, analyses revealed that increases in sleep reactivity predicted greater depression (p<.001) and anxiety (p<.001) at insomnia onset. The impact of sensitization on depression was stable at 2-y follow-up (p=.01). Conclusions Evidence supports sensitization of the sleep system as consequence of insomnia development and major life stress among individuals with low premorbid sleep reactivity. Sleep system sensitization may serve as a mechanism by which insomnia is perpetuated. Harmful effects of the sensitization process may increase risk for insomnia-related depression and anxiety. PMID:27448474

Sleep system sensitization: evidence for changing roles of etiological factors in insomnia.

PubMed

Kalmbach, David A; Pillai, Vivek; Arnedt, J Todd; Anderson, Jason R; Drake, Christopher L

2016-05-01

To test for sensitization of the sleep system in response to insomnia development and major life stress. In addition, to evaluate the impact on depression and anxiety associated with sleep system sensitization. A longitudinal study with three annual assessments. The community-based sample included 262 adults with no history of insomnia or depression who developed insomnia one year after baseline (67.6% female; 44.0 ± 13.4 yr). Measures included the Ford Insomnia Response to Stress Test to assess sleep reactivity, Quick Inventory of Depressive Symptomatology, and Beck Anxiety Inventory. Insomnia classification was based on DSM-IV criteria. Sleep system sensitization was operationally defined as significant increases in sleep reactivity. Sensitization of the sleep system was observed from baseline to insomnia onset at 1-yr follow-up among insomniacs with low premorbid vulnerability (p < 0.001), resulting in 68.3% of these individuals re-classified as highly sleep reactive. Major life stress was associated with greater sleep system sensitization (p = 0.02). Results showed that sleep reactivity at 2-yr follow-up remained elevated among those with low premorbid vulnerability, even after insomnia remission (p < 0.01). Finally, analyses revealed that increases in sleep reactivity predicted greater depression (p < 0.001) and anxiety (p < 0.001) at insomnia onset. The impact of sensitization on depression was stable at 2-yr follow-up (p = 0.01). Evidence supports sensitization of the sleep system as a consequence of insomnia development and major life stress among individuals with low premorbid sleep reactivity. Sleep system sensitization may serve as a mechanism by which insomnia is perpetuated. Harmful effects of the sensitization process may increase risk for insomnia-related depression and anxiety. Copyright © 2016 Elsevier B.V. All rights reserved.

Mechanism and Characteristics of Humidity Sensing with Polyvinyl Alcohol-Coated Fiber Surface Plasmon Resonance Sensor.

PubMed

Shao, Yu; Wang, Ying; Cao, Shaoqing; Huang, Yijian; Zhang, Longfei; Zhang, Feng; Liao, Changrui; Wang, Yiping

2018-06-25

A surface plasmon resonance (SPR) sensor based on a side-polished single mode fiber coated with polyvinyl alcohol (PVA) is demonstrated for relative humidity (RH) sensing. The SPR sensor exhibits a resonant dip in the transmission spectrum in ambient air after PVA film coating, and the resonant wavelength shifts to longer wavelengths as the thickness of the PVA film increases. When RH changes, the resonant dip of the sensor with different film-thicknesses exhibits interesting characteristics for optical spectrum evolution. For sensors with initial wavelengths between 550 nm and 750 nm, the resonant dip shifts to longer wavelengths with increasing RH. The averaged sensitivity increases firstly and then drops, and shows a maximal sensitivity of 1.01 nm/RH%. Once the initial wavelength of the SPR sensor exceeds 850 nm, an inflection point of the resonant wavelength shift can be observed with RH increasing, and the resonant dip shifts to shorter wavelengths for RH values exceeding this point, and sensitivity as high as −4.97 nm/RH% can be obtained in the experiment. The sensor is expected to have potential applications in highly sensitive and cost effective humidity sensing.

New design of a passive type RADFET reader for enhanced sensitivity

NASA Astrophysics Data System (ADS)

Lee, Dae-Hee

2016-07-01

We present a new design of a passive type RADFET reader with enhanced radiation sensitivity. Using a electostatic plate, we have applied a static electric field to the gate voltage, which impacts a positive biasing on the p-type MOSFET. The resultant effect shows that 1.8 times of radiation sensitivity increased when we measured the threshold voltage shift of the RADFET exposed to 30 krad irradiation. We discuss further about the characteristic changes of a RADFET according to the positive biasing on the gate voltage.

Maternal and child correlates of anxiety in 2½-year-old children.

PubMed

Mount, Kristin S; Crockenberg, Susan C; Jó, Patricia S Bárrig; Wagar, Jessica-Lyn

2010-12-01

The goal of this study was to predict the development of anxiety in 2½ year olds as a function of maternal anxiety and child inhibited temperament, and to test the mediating, moderating, and curvilinear effects of maternal sensitivity. Participants were 83 mothers and their 2½-year-old children (32 females). Maternal anxiety, child inhibition, and child anxiety were assessed by maternal report. Maternal sensitivity was rated based on the appropriateness and timeliness of mothers' responses to children's fear observed during their exposure to novel events in the laboratory and from mothers' diaries documenting their responses to children's fear in everyday situations. Gender predicted child anxiety, with mothers reporting girls as more anxious, as did child inhibition, with more inhibited children exhibiting more anxiety. Maternal sensitivity predicted child anxiety as a main effect and, in addition, inhibition moderated the curvilinear association of maternal sensitivity and child anxiety. For highly inhibited children, maternal sensitivity predicted anxiety in both a negative linear and a curvilinear fashion; anxiety decreased as maternal sensitivity increased up to a moderately high level, then increased at very high levels of maternal sensitivity. For less inhibited children, maternal sensitivity showed only a significant negative linear association with child anxiety. Copyright © 2010. Published by Elsevier Inc.

The MAPKK FgMkk1 of Fusarium graminearum regulates vegetative differentiation, multiple stress response, and virulence via the cell wall integrity and high-osmolarity glycerol signaling pathways.

PubMed

Yun, Yingzi; Liu, Zunyong; Zhang, Jingze; Shim, Won-Bo; Chen, Yun; Ma, Zhonghua

2014-07-01

Mitogen-activated protein (MAP) kinases play crucial roles in regulating fungal development, growth and pathogenicity, and in responses to the environment. In this study, we characterized a MAP kinase kinase FgMkk1 in Fusarium graminearum, the causal agent of wheat head blight. Phenotypic analyses of the FgMKK1 mutant (ΔFgMKK1) showed that FgMkk1 is involved in the regulation of hyphal growth, pigmentation, conidiation, deoxynivalenol biosynthesis and virulence of F. graminearum. ΔFgMKK1 also showed increased sensitivity to cell wall-damaging agents, and to osmotic and oxidative stresses, but exhibited decreased sensitivity to the fungicides iprodione and fludioxonil. In addition, the mutant revealed increased sensitivity to a biocontrol agent, Trichoderma atroviride. Western blot assays revealed that FgMkk1 positively regulates phosphorylation of the MAP kinases Mgv1 and FgOs-2, the key component in the cell wall integrity (CWI) and high-osmolarity glycerol (HOG) signalling pathway respectively. Yeast two-hybrid assay indicated that Mgv1 interacts with a transcription factor FgRlm1. The FgRLM1 mutant (ΔFgRLM1) showed increased sensitivity to cell wall-damaging agents and exhibited decreased virulence. Taken together, our data indicated that FgMkk1 is an upstream component of Mgv1, and regulates vegetative differentiation, multiple stress response and virulence via the CWI and HOG signalling pathways. FgRlm1 may be a downstream component of Mgv1 in the CWI pathway in F. graminearum. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

Positron emission tomography with α-[11C]methyl-L-tryptophan in tuberous sclerosis complex-related epilepsy.

PubMed

Rubí, Sebastià; Costes, Nicolas; Heckemann, Rolf A; Bouvard, Sandrine; Hammers, Alexander; Martí Fuster, Berta; Ostrowsky, Karine; Montavont, Alexandra; Jung, Julien; Setoain, Xavier; Catenoix, Hélène; Hino, Keiko; Liger, François; Le Bars, Didier; Ryvlin, Philippe

2013-12-01

Tuberous sclerosis complex (TSC) is often associated with cerebral tubers and medically intractable epilepsy. We reevaluated whether increased uptake of α-[(11) C]methyl-l-tryptophan (AMT) in cerebral tubers is associated with tuber epileptogenicity. We included 12 patients (six male, 4-53 years old) with TSC and refractory seizures who were evaluated for epilepsy surgery in our center, including video-electroencephalographic (EEG) monitoring, fluid-attenuated inversion recovery magnetic resonance imaging (FLAIR MRI), and positron emission tomography (PET) with α-[(11) C]methyl-l-tryptophan (AMT-PET). Nine of these 12 patients also underwent intracerebral EEG recording. AMT uptake in each tuber was visually evaluated on PET coregistered with MRI. An AMT uptake index based on lesional/healthy cortex ratio was also calculated. Sensitivity and specificity values of AMT-PET in the detection of epileptogenic lesions were obtained, using the available electroclinical and neuroimaging evidence as the gold standard for epileptogenicity. A total of 126 tubers were identified. Two of 12 patients demonstrated a tuber with clearly increased AMT uptake, one of whom also showed a subtle increased AMT uptake in another contralateral tuber. Four other patients showed only subtle increased AMT uptake. The only two tubers with clearly increased AMT uptake proved to be epileptogenic based on intracerebral EEG data, whereas none of the tubers associated with subtle increased AMT uptake were involved at ictal onset. In a per-patient approach, this yielded a sensitivity of clearly increased AMT uptake in detecting tuber epileptogenicity of 17% (2/12 patients), whereas the per-lesion sensitivity and specificity were 12% (95% confidence interval [CI]: 3-34%) and 100% (95% CI: 97-100%), respectively. AMT-PET is a specific neuroimaging technique in the identification of epileptogenic tubers in TSC. Despite its low sensitivity, the clinical usefulness of AMT-PET still deserves to be considered according to the challenging complexity of epilepsy surgery in tuberous sclerosis. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

Jicama (Pachyrhizus erosus) extract increases insulin sensitivity and regulates hepatic glucose in C57BL/Ksj-db/db mice.

PubMed

Park, Chan Joo; Lee, Hyun-Ah; Han, Ji-Sook

2016-01-01

This study investigated the effect of jicama extract on hyperglycemia and insulin sensitivity in an animal model of type 2 diabetes. Male C57BL/Ksj-db/db mice were divided into groups subsequently fed a regular diet (controls), or diet supplemented with jicama extract, and rosiglitazone. After 6 weeks, blood levels of glucose and glycosylated hemoglobin were significantly lower in animals administered the jicama extract than the control group. Additionally, glucose and insulin tolerance tests showed that jicama extract increased insulin sensitivity. The homeostatic index of insulin resistance was lower in the jicama extract-treated group than in the diabetic control group. Administration of jicama extract significantly enhanced the expressions of the phosphorylated AMP-activated protein kinase and Akt substrate of 160 kDa, and plasma membrane glucose transporter type 4 in skeletal muscle. Jicama extract administration also decreased the expressions of glucose 6-phosphatase and phosphoenol pyruvate carboxykinase in the liver. Jicama extract may increases insulin sensitivity and inhibites the gluconeogenesis in the liver.

Jicama (Pachyrhizus erosus) extract increases insulin sensitivity and regulates hepatic glucose in C57BL/Ksj-db/db mice

PubMed Central

Park, Chan Joo; Lee, Hyun-Ah; Han, Ji-Sook

2016-01-01

This study investigated the effect of jicama extract on hyperglycemia and insulin sensitivity in an animal model of type 2 diabetes. Male C57BL/Ksj-db/db mice were divided into groups subsequently fed a regular diet (controls), or diet supplemented with jicama extract, and rosiglitazone. After 6 weeks, blood levels of glucose and glycosylated hemoglobin were significantly lower in animals administered the jicama extract than the control group. Additionally, glucose and insulin tolerance tests showed that jicama extract increased insulin sensitivity. The homeostatic index of insulin resistance was lower in the jicama extract-treated group than in the diabetic control group. Administration of jicama extract significantly enhanced the expressions of the phosphorylated AMP-activated protein kinase and Akt substrate of 160 kDa, and plasma membrane glucose transporter type 4 in skeletal muscle. Jicama extract administration also decreased the expressions of glucose 6-phosphatase and phosphoenol pyruvate carboxykinase in the liver. Jicama extract may increases insulin sensitivity and inhibites the gluconeogenesis in the liver. PMID:26798198

Loss-of-function myostatin mutation increases insulin sensitivity and browning of white fat in Meishan pigs.

PubMed

Cai, Chunbo; Qian, Lili; Jiang, Shengwang; Sun, Youde; Wang, Qingqing; Ma, Dezun; Xiao, Gaojun; Li, Biao; Xie, Shanshan; Gao, Ting; Chen, Yaoxing; Liu, Jie; An, Xiaorong; Cui, Wentao; Li, Kui

2017-05-23

Myostatin-deficient mice showed a remarkable hypertrophy of skeletal muscle, with a decreased fat mass and enhanced insulin sensitivity. Currently, it is unclear if the inhibition of myostatin could be used as an approach to treat human obesity and insulin resistance. In this study, we investigated if the inhibition of porcine myostatin has any effect on fat deposition and insulin sensitivity using genetically engineered Meishan pigs containing a myostatin loss-of-function mutation (Mstn -/- ). Our results indicated that, when compared with wild-type pigs, the amount of subcutaneous fat and leaf fat of Mstn -/- pigs were significantly decreased mainly due to the browning of subcutaneous adipose tissue. Additionally, the serum insulin level decreased and the insulin sensitivity increased significantly in Mstn -/- pigs. Moreover, we found a significant increase in levels of insulin receptor and insulin receptor substrate proteins in skeletal muscle of Mstn -/- pigs, which then activating the insulin signaling pathway. Irisin-mediated regulation is not the only pathway for the activation of insulin signal in Mstn -/- skeletal muscle. This study provides valuable insight for the treatment of human obesity and diabetes mellitus.

Enhancement of the sensitivity of gas sensor based on microstructure optical fiber

NASA Astrophysics Data System (ADS)

Morshed, Monir; Hasan, Md. Imran; Razzak, S. M. Abdur

2015-12-01

This paper proposes the design and characterization of microstructure optical fiber for gas sensing applications. The aim is to detect toxic and colorless gases over a wide transmission band covering 0.80 µm to 2.00 µm wavelength. Numerical investigation is carried out by using the finite element method (FEM). The numerical study shows that sensitivity of the proposed sensor is moderately increased by introducing four non-circular holes around the defected core of photonic crystal fiber and the confinement loss is also reduced. Furthermore, we confirm that increasing the diameter of central air core and size of the non-circular holes can improve the relative sensitivity and the confinement loss is reduced by increasing the diameter of air holes in the cladding. The enhancement of the relative sensitivity is more than 27.58% (0.1323 to 0.1688) at the wavelength λ=1.33µm that is the absorption line of methane (CH4) and hydrogen fluoride (HF) gases. The confinement loss of the fiber is 1.765×10-8 dB/m.

Effect of microstructure on stress corrosion cracking of alloy 600 and alloy 690 in 40% NaOH

NASA Astrophysics Data System (ADS)

Kim, H. P.; Hwang, S. S.; Lim, Y. S.; Kuk, I. H.; Kim, J. S.

2001-02-01

Stress corrosion cracking (SCC) behaviors of Alloy 600, Alloy 690 and the Ni-10Cr-10Fe alloy have been studied using a C-ring in 40% NaOH solution at 315°C. The current density of Alloy 690 in polarization curves was higher at 200 mV above corrosion potential than that of Alloy 600. SCC resistance increased with Cr content for the chromium carbide free alloys, probably due to facilitation of SCC crack tip blunting with an increase in Cr content. Both thermally treated Alloy 600 and sensitized Alloy 600 have a comparable amount of intergranular carbide. But the former is more resistant to SCC than the latter, which might be attributed to the presence of the slight Cr depletion around the grain boundary in the former one. Sensitized Alloy 600 showed higher SCC resistance than the solution annealed one due to intergranular carbide in sensitized Alloy 600. This implies that the beneficial effect of intergranular carbide overrides the harmful effects of Cr depletion for sensitized Alloy 600. SCC resistance of Alloy 600 increased with grain size.

Technological advances in cosmogenic neutron detectors for measuring soil water content

NASA Astrophysics Data System (ADS)

Zreda, M. G.; Schrön, M.; Köhli, M.

2017-12-01

The cosmic-ray neutron probe is used for measuring area-average soil water content at the hectometer scale. Early work showed a simple exponential decrease with distance of the instrument's sensitivity and a footprint 300 m in radius. Recent research suggested a much higher sensitivity to local neutrons and reduced footprint. We show results confirming the high sensitivity to local neutrons, describe two ways to reduce local and increase far-field effects, and propose ways of measuring neutrons at different spatial scales. Measurements with moderated detectors across a 10-m-wide creek and a 2-m-wide water tank show a decrease by 30% and 20%, respectively, of neutron intensity over water compared to that over land nearby. These results mean that the detector is sensitive to meter-scale heterogeneities of water content. This sensitivity can be reduced by rising the detector or by shielding it from local neutrons. The effect of local water distributions on the measured neutron intensity decreases with height. In the water tank experiment it disappeared almost completely at the height of 2 m, leading to the conjecture that the height roughly equal to the horizontal scale of heterogeneity would eliminate the sensitivity. This may or may not be practical. Shielding the detector below by a hydrogenous material removes a substantial fraction of the local neutrons. The shielded detector has a reduced count rate, reduced sensitivity to local neutrons and increased sensitivity to neutrons farther afield, and a larger footprint. Such a detector could be preferable to the current cosmogenic-neutron probe under heterogeneous soil water conditions. The shielding experiments also inspired the development of a local-area neutron detector. It has hydrogenous neutron shields on all sides except the bottom, substantially blocking the neutrons coming from afar, while allowing the neutrons coming directly from below. Its footprint is equal to its physical dimension when the detector is placed on the surface. Once this detector is calibrated, it can be useful in calibrating the wide-area detector, for example over stony soils that are difficult to sample physically for water content determination, and in high-resolution mapping of neutron intensity and soil moisture.

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

Harmon, S; Jeraj, R; Galavis, P

Purpose: Sensitivity of PET-derived texture features to reconstruction methods has been reported for features extracted from axial planes; however, studies often utilize three dimensional techniques. This work aims to quantify the impact of multi-plane (3D) vs. single-plane (2D) feature extraction on radiomics-based analysis, including sensitivity to reconstruction parameters and potential loss of spatial information. Methods: Twenty-three patients with solid tumors underwent [{sup 18}F]FDG PET/CT scans under identical protocols. PET data were reconstructed using five sets of reconstruction parameters. Tumors were segmented using an automatic, in-house algorithm robust to reconstruction variations. 50 texture features were extracted using two Methods: 2D patchesmore » along axial planes and 3D patches. For each method, sensitivity of features to reconstruction parameters was calculated as percent difference relative to the average value across reconstructions. Correlations between feature values were compared when using 2D and 3D extraction. Results: 21/50 features showed significantly different sensitivity to reconstruction parameters when extracted in 2D vs 3D (wilcoxon α<0.05), assessed by overall range of variation, Rangevar(%). Eleven showed greater sensitivity to reconstruction in 2D extraction, primarily first-order and co-occurrence features (average Rangevar increase 83%). The remaining ten showed higher variation in 3D extraction (average Range{sub var}increase 27%), mainly co-occurence and greylevel run-length features. Correlation of feature value extracted in 2D and feature value extracted in 3D was poor (R<0.5) in 12/50 features, including eight co-occurrence features. Feature-to-feature correlations in 2D were marginally higher than 3D, ∣R∣>0.8 in 16% and 13% of all feature combinations, respectively. Larger sensitivity to reconstruction parameters were seen for inter-feature correlation in 2D(σ=6%) than 3D (σ<1%) extraction. Conclusion: Sensitivity and correlation of various texture features were shown to significantly differ between 2D and 3D extraction. Additionally, inter-feature correlations were more sensitive to reconstruction variation using single-plane extraction. This work highlights a need for standardized feature extraction/selection techniques in radiomics.« less

Caffeine and length dependence of staircase potentiation in skeletal muscle.

PubMed

Rassier, D E; Tubman, L A; MacIntosh, B R

1998-01-01

Skeletal muscle sensitivity to Ca2+ is greater at long lengths, and this results in an optimal length for twitch contractions that is longer than optimal length for tetanic contractions. Caffeine abolishes this length dependence of Ca2+ sensitivity. Muscle length (ML) also affects the degree of staircase potentiation. Since staircase potentiation is apparently caused by an increased Ca2+ sensitivity of the myofilaments, we tested the hypothesis that caffeine depresses the length dependence of staircase potentiation. In situ isometric twitch contractions of rat gastrocnemius muscle before and after 10 s of 10-Hz stimulation were analyzed at seven different lengths to evaluate the length dependence of staircase potentiation. In the absence of caffeine, length dependence of Ca2+ sensitivity was observed, and the degree of potentiation after 10-Hz stimulation showed a linear decrease with increased length (DT = 1.47 - 0.05 ML, r2 = 0.95, where DT is developed tension). Length dependence of Ca2+ sensitivity was decreased by caffeine when caffeine was administered in amounts estimated to result in 0.5 and 0.75 mM concentrations. Furthermore, the negative slope of the relationship between staircase potentiation and muscle length was diminished at the lower caffeine dose, and the slope was not different from zero after the higher dose (DT = 1.53 - 0.009 ML, r2 = 0.43). Our study shows that length dependence of Ca2+ sensitivity in intact skeletal muscle is diminished by caffeine. Caffeine also suppressed the length dependence of staircase potentiation, suggesting that the mechanism of this length dependence may be closely related to the mechanism for length dependence of Ca2+ sensitivity.

Re-establishment of Anxiety in Stress-Sensitized Mice Is Caused by Monocyte Trafficking from the Spleen to the Brain

PubMed Central

Wohleb, Eric S.; McKim, Daniel B.; Shea, Daniel T.; Powell, Nicole D.; Tarr, Andrew J.; Sheridan, John F.; Godbout, Jonathan P.

2014-01-01

Background Persistent anxiety-like symptoms may have an inflammatory-related pathophysiology. Our previous work using repeated social defeat (RSD) in mice showed that recruitment of peripheral myeloid cells to the brain is required for the development of anxiety. Here, we aimed to determine if 1) RSD promotes prolonged anxiety through redistribution of myeloid cells and 2) prior exposure to RSD sensitizes the neuroimmune axis to secondary subthreshold stress. Methods Mice were subjected to RSD and several immune and behavioral parameters were determined 0.5, 8, or 24 days later. In follow-up studies, control and RSD mice were subjected to subthreshold stress at 24 days. Results Repeated social defeat-induced macrophage recruitment to the brain corresponded with development and maintenance of anxiety-like behavior 8 days after RSD, but neither remained at 24 days. Nonetheless, social avoidance and an elevated neuroinflammatory profile were maintained at 24 days. Subthreshold social defeat in RSD-sensitized mice increased peripheral macrophage trafficking to the brain that promoted re-establishment of anxiety. Moreover, subthreshold social defeat increased social avoidance in RSD-sensitized mice compared with naïve mice. Stress-induced monocyte trafficking was linked to redistribution of myeloid progenitor cells in the spleen. Splenectomy before subthreshold stress attenuated macrophage recruitment to the brain and prevented anxiety-like behavior in RSD-sensitized mice. Conclusions These data indicate that monocyte trafficking from the spleen to the brain contributes re-establishment of anxiety in stress-sensitized mice. These findings show that neuroinflammatory mechanisms promote mood disturbances following stress-sensitization and outline novel neuroimmune interactions that underlie recurring anxiety disorders such as posttraumatic stress disorder. PMID:24439304

Re-establishment of anxiety in stress-sensitized mice is caused by monocyte trafficking from the spleen to the brain.

PubMed

Wohleb, Eric S; McKim, Daniel B; Shea, Daniel T; Powell, Nicole D; Tarr, Andrew J; Sheridan, John F; Godbout, Jonathan P

2014-06-15

Persistent anxiety-like symptoms may have an inflammatory-related pathophysiology. Our previous work using repeated social defeat (RSD) in mice showed that recruitment of peripheral myeloid cells to the brain is required for the development of anxiety. Here, we aimed to determine if 1) RSD promotes prolonged anxiety through redistribution of myeloid cells and 2) prior exposure to RSD sensitizes the neuroimmune axis to secondary subthreshold stress. Mice were subjected to RSD and several immune and behavioral parameters were determined .5, 8, or 24 days later. In follow-up studies, control and RSD mice were subjected to subthreshold stress at 24 days. Repeated social defeat-induced macrophage recruitment to the brain corresponded with development and maintenance of anxiety-like behavior 8 days after RSD, but neither remained at 24 days. Nonetheless, social avoidance and an elevated neuroinflammatory profile were maintained at 24 days. Subthreshold social defeat in RSD-sensitized mice increased peripheral macrophage trafficking to the brain that promoted re-establishment of anxiety. Moreover, subthreshold social defeat increased social avoidance in RSD-sensitized mice compared with naïve mice. Stress-induced monocyte trafficking was linked to redistribution of myeloid progenitor cells in the spleen. Splenectomy before subthreshold stress attenuated macrophage recruitment to the brain and prevented anxiety-like behavior in RSD-sensitized mice. These data indicate that monocyte trafficking from the spleen to the brain contributes re-establishment of anxiety in stress-sensitized mice. These findings show that neuroinflammatory mechanisms promote mood disturbances following stress-sensitization and outline novel neuroimmune interactions that underlie recurring anxiety disorders such as posttraumatic stress disorder. Copyright © 2014 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Basal plasma insulin and homeostasis model assessment (HOMA) are indicators of insulin sensitivity in cats.

PubMed

Appleton, D J; Rand, J S; Sunvold, G D

2005-06-01

The objective of this study was to compare simpler indices of insulin sensitivity with the minimal model-derived insulin sensitivity index to identify a simple and reliable alternative method for assessing insulin sensitivity in cats. In addition, we aimed to determine whether this simpler measure or measures showed consistency of association across differing body weights and glucose tolerance levels. Data from glucose tolerance and insulin sensitivity tests performed in 32 cats with varying body weights (underweight to obese), including seven cats with impaired glucose tolerance, were used to assess the relationship between Bergman's minimal model-derived insulin sensitivity index (S(I)), and various simpler measures of insulin sensitivity. The most useful overall predictors of insulin sensitivity were basal plasma insulin concentrations and the homeostasis model assessment (HOMA), which is the product of basal glucose and insulin concentrations divided by 22.5. It is concluded that measurement of plasma insulin concentrations in cats with food withheld for 24 h, in conjunction with HOMA, could be used in clinical research projects and by practicing veterinarians to screen for reduced insulin sensitivity in cats. Such cats may be at increased risk of developing impaired glucose tolerance and type 2 diabetes mellitus. Early detection of these cats would enable preventative intervention programs such as weight reduction, increased physical activity and dietary modifications to be instigated.

Childhood Adversity and Pain Sensitization.

PubMed

You, Dokyoung Sophia; Meagher, Mary W

Childhood adversity is a vulnerability factor for chronic pain. However, the underlying pain mechanisms influenced by childhood adversity remain unknown. The aim of the current study was to evaluate the impact of childhood adversity on dynamic pain sensitivity in young adults. After screening for childhood adverse events and health status, healthy individuals reporting low (below median; n = 75) or high levels of adversity (the top 5%; n = 51) were invited for pain testing. Both groups underwent heat pain threshold and temporal summation of second pain (TSSP) testing after reporting depressive symptoms. TSSP refers to a progressive increase in pain intensity with repetition of identical noxious stimuli and is attributed to central sensitization. Changes in pain ratings over time (slope) were computed for TSSP sensitization and decay of subsequent aftersensations. The high-adversity group showed greater TSSP sensitization (meanslope, 0.75; SDpositive slope, 1.78), and a trend toward a slower decay (meanslope, -11.9; SD, 3.4), whereas the low-adversity group showed minimal sensitization (meanslope, 0.07; SDnear-zero slope, 1.77), F(1,123) = 5.84, p = .017 and faster decay (meanslope, -13.1; SD, 3.4), F(1,123) = 3.79, p = .054. This group difference remained significant even after adjusting for adult depressive symptoms (p = .033). No group difference was found in heat pain threshold (p = .85). Lastly, the high-adversity group showed blunted cardiac and skin conductance responses. These findings suggest that enhancement of central sensitization may provide a mechanism underlying the pain hypersensitivity and chronicity linked to childhood adversity.

Response of the iron-deficient erythrocyte in the rat to hyperoxia

NASA Technical Reports Server (NTRS)

Larkin, E. C.; Kimzey, S. L.; Siler, K.

1978-01-01

Normal and iron-deficient rats were exposed to 90% O2 at 760 Torr for 24 or 48 h. Erythrocyte response to hyperoxia was monitored by potassium (rubidium) influx studies, by storage stress, and by ultrastructural studies. Normal rat erythrocytes exhibited morphological changes and decrease of ouabain-sensitive potassium influx compared to unexposed controls. Both components of erythrocyte potassium influx were affected by iron deficiency. Erythrocytes from unexposed iron-deficient rats showed a 50% increase in ouabain-sensitive potassium influx compared to controls. Iron-deficient rats exposed to hyperoxia for 24 or 48 h, had erythrocytes with morphological changes. Erythrocytes of iron-deficient rats exposed for 24 h showned no influx change; those exposed for 48 h showed a decrease of ouabain-sensitive influx compared to erythrocytes of controls.

Improvement of a PCR test to diagnose infection by Mansonella ozzardi.

PubMed

Vera, Luana Janaína Souza; Basano, Sergio de Almeida; Camargo, Juliana de Souza Almeida Aranha; França, Andonai Krauze de; Ferreira, Ricardo de Godoi Mattos; Casseb, Almeida Andrade; Medeiros, Jansen Fernandes; Fontes, Gilberto; Camargo, Luís Marcelo Aranha

2011-01-01

Mansonelliasis is caused by Mansonella ozzardi. It is widespread in the Amazon region, with a high prevalence. The common exam of thick blood smears stained with Giemsa shows low efficacy levels and has been an obstacle to diagnosing individuals with low blood parasitemia. In order to increase diagnosis efficacy, the PCR technique was improved. PCR demonstrated the best performance, with sensitivity and negative predictive values (NPV) of 100%, followed by blood filtration through membrane filters, which showed a sensitivity of 88.9% and a NPV of 84.6%, when compared to thick blood smears.

Increasing species richness of the macrozoobenthic fauna on tidal flats of the Wadden Sea by local range expansion and invasion of exotic species

NASA Astrophysics Data System (ADS)

Beukema, J. J.; Dekker, R.

2011-06-01

A 40-y series of consistently collected samples (15 fixed sampling sites, constant sampled area of 15 × 0.95 m2, annual sampling only in late-winter/early-spring seasons, and consistent sieving and sorting procedures; restriction to 50 easily recognizable species) of macrozoobenthos on Balgzand, a tidal flat area in the westernmost part of the Wadden Sea (The Netherlands), revealed significantly increasing trends of species richness. Total numbers of species annually encountered increased from ~28 to ~38. Mean species density (number of species found per sampling site) increased from ~13 to ~18 per 0.95 m2. During the 40 years of the 1970-2009 period of observation, 4 exotic species invaded the area: (in order of first appearance) Ensis directus, Marenzelleria viridis, Crassostrea gigas, and Hemigrapsus takanoi. Another 5 species recently moved to Balgzand from nearby (subtidal) locations. Together, these 9 new species on the tidal flats explained by far most of the increase in total species numbers, but accounted for only one-third of the observed increase in species density (as a consequence of the restricted distribution of most of them). Species density increased particularly by a substantial number of species that showed increasing trends in the numbers of tidal flat sites they occupied. Most of these wider-spreading species were found to suffer from cold winters. During the 40-y period of observation, winter temperatures rose by about 2°C and cold winters became less frequent. The mean number of cold-sensitive species found per site significantly increased by almost 2 per 0.95 m2. Among the other species (not sensitive to low winter temperatures), 6 showed a rising and 2 a declining trend in number of occupied sites, resulting in a net long-term increase in species density amounting to another gain of 1.6 per 0.95 m2. Half of the 50 studied species did not show such long-term trend, nor were invaders. Thus, each of 3 groups (local or alien invaders/winter-sensitive species/other increasing species) contributed to a roughly similar extent to the overall increase in species density.

Applying Cost-Sensitive Extreme Learning Machine and Dissimilarity Integration to Gene Expression Data Classification.

PubMed

Liu, Yanqiu; Lu, Huijuan; Yan, Ke; Xia, Haixia; An, Chunlin

2016-01-01

Embedding cost-sensitive factors into the classifiers increases the classification stability and reduces the classification costs for classifying high-scale, redundant, and imbalanced datasets, such as the gene expression data. In this study, we extend our previous work, that is, Dissimilar ELM (D-ELM), by introducing misclassification costs into the classifier. We name the proposed algorithm as the cost-sensitive D-ELM (CS-D-ELM). Furthermore, we embed rejection cost into the CS-D-ELM to increase the classification stability of the proposed algorithm. Experimental results show that the rejection cost embedded CS-D-ELM algorithm effectively reduces the average and overall cost of the classification process, while the classification accuracy still remains competitive. The proposed method can be extended to classification problems of other redundant and imbalanced data.

Single input state, single–mode fiber–based polarization sensitive optical frequency domain imaging by eigenpolarization referencing

PubMed Central

Lippok, Norman; Villiger, Martin; Jun, Chang–Su; Bouma, Brett E.

2015-01-01

Fiber–based polarization sensitive OFDI is more challenging than free–space implementations. Using multiple input states, fiber–based systems provide sample birefringence information with the benefit of a flexible sample arm but come at the cost of increased system and acquisition complexity, and either reduce acquisition speed or require increased acquisition bandwidth. Here we show that with the calibration of a single polarization state, fiber–based configurations can approach the conceptual simplicity of traditional free–space configurations. We remotely control the polarization state of the light incident at the sample using the eigenpolarization states of a wave plate as a reference, and determine the Jones matrix of the output fiber. We demonstrate this method for polarization sensitive imaging of biological samples. PMID:25927775

Double-Sided Transparent TiO2 Nanotube/ITO Electrodes for Efficient CdS/CuInS2 Quantum Dot-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Chen, Chong; Ling, Lanyu; Li, Fumin

2017-01-01

In this paper, to improve the power conversion efficiencies (PCEs) of quantum dot-sensitized solar cells (QDSSCs) based on CdS-sensitized TiO2 nanotube (TNT) electrodes, two methods are employed on the basis of our previous work. First, by replacing the traditional single-sided working electrodes, double-sided transparent TNT/ITO (DTTO) electrodes are prepared to increase the loading amount of quantum dots (QDs) on the working electrodes. Second, to increase the light absorption of the CdS-sensitized DTTO electrodes and improve the efficiency of charge separation in CdS-sensitized QDSSCs, copper indium disulfide (CuInS2) is selected to cosensitize the DTTO electrodes with CdS, which has a complementary property of light absorption with CdS. The PCEs of QDSSCs based on these prepared QD-sensitized DTTO electrodes are measured. Our experimental results show that compared to those based on the CdS/DTTO electrodes without CuInS2, the PCEs of the QDSSCs based on CdS/CuInS2-sensitized DTTO electrode are significantly improved, which is mainly attributed to the increased light absorption and reduced charge recombination. Under simulated one-sun illumination, the best PCE of 1.42% is achieved for the QDSSCs based on CdS(10)/CuInS2/DTTO electrode, which is much higher than that (0.56%) of the QDSSCs based on CdS(10)/DTTO electrode.

Experimental results for characterization of a tapered plastic optical fiber sensor based on SPR

NASA Astrophysics Data System (ADS)

Cennamo, N.; Galatus, R.; Zeni, L.

2015-05-01

The experimental results obtained with two different Plastic Optical Fiber (POF) geometries, tapered and not-tapered, for a sensor based on Surface Plasmon Resonance (SPR) are presented. SPR is used for determining the refractive index variations at the interface between a gold layer and a dielectric medium (aqueous medium). In this work SPR sensors in POF configurations, useful for bio-sensing applications, have been realized for the optimization of the sensitivity and experimentally tested. The results show as the sensitivity increases with the tapered POF configuration, when the refractive index of aqueous medium increases.

RAPAMYCIN INCREASES LENGTH AND MECHANOSENSORY FUNCTION OF PRIMARY CILIA IN RENAL EPITHELIAL AND VASCULAR ENDOTHELIAL CELLS.

PubMed

Sherpa, Rinzhin T; Atkinson, Kimberly F; Ferreira, Viviana P; Nauli, Surya M

2016-12-01

Primary cilia arebiophysically-sensitive organelles responsible for sensing fluid-flow and transducing this stimulus into intracellular responses. Previous studies have shown that the primary cilia mediate flow-induced calcium influx, and sensitivity of cilia function to flow is correlated to cilia length. Cells with abnormal cilia length or function can lead to a host of diseases that are collectively termed as ciliopathies. Rapamycin, a potent inhibitor of mTOR (mammalian target of rapamycin), has been demonstrated to be a potential pharmacological agent against the aberrant mTOR signaling seen in ciliopathies such as polycystic kidney disease (PKD) and tuberous sclerosis complex (TSC). Here we look at the effects of rapamycin on ciliary length and function for the first time. Compared to controls, primary cilia in rapamycin-treated porcine renal epithelial and mouse vascular endothelial cells showed a significant increase in length. Graded increases in fluid-shear stress further indicates that rapamycin enhances cilia sensitivity to fluid flow. Treatment with rapamycin led to G0 arrest in porcine epithelial cells while no significant change in cell cycle were observed in rapamycin-treated mouse epithelial or endothelial cells, indicating a species-specific effect of rapamycin. Given the previousin vitro and in vivo studies establishing rapamycin as a potential therapeutic agent for ciliopathies, such as PKD and TSC, our studies show that rapamycin enhances ciliary function and sensitivity to fluid flow. The results of our studies suggest a potential ciliotherapeutic effect of rapamycin.

Evaluation of DNA damage induced by gamma radiation in gill and muscle tissues of Cyprinus carpio and their relative sensitivity.

PubMed

M K, Praveen Kumar; Shyama, Soorambail K; D'Costa, Avelyno; Kadam, Samit B; Sonaye, Bhagatsingh Harisingh; Chaubey, Ramesh Chandra

2017-10-01

The effect of radiation on the aquatic environment is of major concern in recent years. Limited data is available on the genotoxicity of gamma radiation on different tissues of aquatic organisms. Hence, the present investigation was carried out to study the DNA damage induced by gamma radiation in the gill and muscle tissues and their relative sensitivity using the comet assay in the freshwater teleost fish, common carp (Cyprinus carpio). The comet assay was optimized and validated in common carp using cyclophosphamide (CP), a reference genotoxic agent. The fish were exposed (acute) to various doses of gamma radiation (2, 4, 6, 8 and 10Gy) and samplings (gill and muscle tissue) were done at regular intervals (24, 48 and 72h) to assess the DNA damage. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA for all doses of gamma radiation in both tissues. We also observed a dose-related increase and a time-dependent decrease of DNA damage. In comparison, DNA damage showed different sensitivity among the tissues at different doses. This shows that a particular dose may have different effects on different tissues which could be due to physiological factors of the particular tissue. Our study also suggests that the gills and muscle of fish are sensitive and reliable tissues for evaluating the genotoxic effects of reference and environmental agents, using the comet assay. Copyright © 2017. Published by Elsevier Inc.

Sensitivity-Based Guided Model Calibration

NASA Astrophysics Data System (ADS)

Semnani, M.; Asadzadeh, M.

2017-12-01

A common practice in automatic calibration of hydrologic models is applying the sensitivity analysis prior to the global optimization to reduce the number of decision variables (DVs) by identifying the most sensitive ones. This two-stage process aims to improve the optimization efficiency. However, Parameter sensitivity information can be used to enhance the ability of the optimization algorithms to find good quality solutions in a fewer number of solution evaluations. This improvement can be achieved by increasing the focus of optimization on sampling from the most sensitive parameters in each iteration. In this study, the selection process of the dynamically dimensioned search (DDS) optimization algorithm is enhanced by utilizing a sensitivity analysis method to put more emphasis on the most sensitive decision variables for perturbation. The performance of DDS with the sensitivity information is compared to the original version of DDS for different mathematical test functions and a model calibration case study. Overall, the results show that DDS with sensitivity information finds nearly the same solutions as original DDS, however, in a significantly fewer number of solution evaluations.

Sensitive strata in Bootlegger Cove Formation

USGS Publications Warehouse

Olsen, Harold W.

1989-01-01

Sensitivity magnitudes are interpreted from remolded strength values in recent subsurface geologic, geotechnical, and geochemical data from the Bootlegger Cove Formation adjacent to the Turnagain Heights Landslide. The results show that strata composed of highly sensitive clays occur in both the middle and lower zones of the formation, and that between these strata the clays are generally of low-to-medium sensitivity. The most sensitive stratum is in the middle zone between two sand layers, and its sensitivity increases from both clay-sand interfaces to a maximum at the center of the stratum. The pore fluid chemistry of the highly sensitive materials differs from that in the materials of low to medium sensitivity only in their concentrations of organic carbon, chloride, bicarbonate, and sulfate. The total dissolved solids concentration is low, and the ratio of monovalent to divalent cations is very high throughout the middle and lower zones of the formation. Of the known causes of high and extremely high sensitivities, only organic and/or anionic dispersants are consistent with these findings.

Human T-Cell Leukemia Virus I Tax Protein Sensitizes p53-Mutant Cells to DNA Damage

PubMed Central

Mihaylova, Valia T.; Green, Allison M.; Khurgel, Moshe; Semmes, Oliver J.; Kupfer, Gary M.

2018-01-01

Mutations in p53 are a common cause of resistance of cancers to standard chemotherapy and, thus, treatment failure. Reports have shown that Tax, a human T-cell leukemia virus type I encoded protein that has been associated with genomic instability and perturbation of transcription and cell cycle, sensitizes HeLa cells to UV treatment. The extent to which Tax can sensitize cells and the mechanism by which it exerts its effect are unknown. In this study, we show that Tax sensitizes p53-mutant cells to a broad range of DNA-damaging agents, including mitomycin C, a bifunctional alkylator, etoposide, a topoisomerase II drug, and UV light, but not ionizing radiation, a double-strand break agent, or vinblastine, a tubulin poison. Tax caused hypersensitivity in all p53-deleted cell lines and several, but not all, mutant-expressed p53–containing cell lines, while unexpectedly being protective in p53 wild-type (wt) cells. The effect observed in p53-deleted lines could be reversed for this by transfection of wt p53. We also show that Tax activates a p53-independent proapoptotic program through decreased expression of the retinoblastoma protein and subsequent increased E2F1 expression. The expression of several proapoptotic proteins was also induced by Tax, including Puma and Noxa, culminating in a substantial increase in Bax dimerization. Our results show that Tax can sensitize p53-mutant cells to DNA damage while protecting p53 wt cells, a side benefit that might result in reduced toxicity in normal cells. Such studies hold the promise of a novel adjunctive therapy that could make cancer chemotherapy more effective. PMID:18559532

Tumoricidal activity of low-energy 160-KV versus 6-MV X-rays against platinum-sensitized F98 glioma cells

PubMed Central

Lim, Sara N.; Pradhan, Anil K.; Barth, Rolf F.; Nahar, Sultana N.; Nakkula, Robin J.; Yang, Weilian; Palmer, Alycia M.; Turro, Claudia; Weldon, Michael; Bell, Erica Hlavin; Mo, Xiaokui

2015-01-01

The purposes of this study were (i) to investigate the differences in effects between 160-kV low-energy and 6-MV high-energy X-rays, both by computational analysis and in vitro studies; (ii) to determine the effects of each on platinum-sensitized F98 rat glioma and murine B16 melanoma cells; and (iii) to describe the in vitro cytotoxicity and in vivo toxicity of a Pt(II) terpyridine platinum (Typ-Pt) complex. Simulations were performed using the Monte Carlo code Geant4 to determine enhancement in absorption of low- versus high-energy X-rays by Pt and to determine dose enhancement factors (DEFs) for a Pt-sensitized tumor phantom. In vitro studies were carried out using Typ-Pt and again with carboplatin due to the unexpected in vivo toxicity of Typ-Pt. Cell survival was determined using clonogenic assays. In agreement with computations and simulations, in vitro data showed up to one log unit reduction in surviving fractions (SFs) of cells treated with 1–4 µg/ml of Typ-Pt and irradiated with 160-kV versus 6-MV X-rays. DEFs showed radiosensitization in the 50–200 keV range, which fell to approximate unity at higher energies, suggesting marginal interactions at MeV energies. Cells sensitized with 1–5 or 7 µg/ml of carboplatin and then irradiated also showed a significant decrease (P < 0.05) in SFs. However, it was unlikely this was due to increased interactions. Theoretical and in vitro studies presented here demonstrated that the tumoricidal activity of low-energy X-rays was greater than that of high-energy X-rays against Pt-sensitized tumor cells. Determining whether radiosensitization is a function of increased interactions will require additional studies. PMID:25266332

Disruption of communication between peripheral and central trigeminovascular neurons mediates the antimigraine action of 5HT1B/1D receptor agonists

PubMed Central

Levy, Dan; Jakubowski, Moshe; Burstein, Rami

2004-01-01

Triptans are 5HT1B/1D receptor agonists commonly prescribed for migraine headache. Although originally designed to constrict dilated intracranial blood vessels, the mechanism and site of action by which triptans abort the migraine pain remain unknown. We showed recently that sensitization of peripheral and central trigeminovascular neurons plays an important role in the pathophysiology of migraine pain. Here we examined whether the drug sumatriptan can prevent and/or suppress peripheral and central sensitization by using single-unit recording in our animal model of intracranial pain. We found that sumatriptan effectively prevented the induction of sensitization (i.e., increased spontaneous firing; increased neuronal sensitivity to intracranial mechanical stimuli) in central trigeminovascular neurons (recorded in the dorsal horn), but not in peripheral trigeminovascular neurons (recorded in the trigeminal ganglion). After sensitization was established in both types of neuron, sumatriptan effectively normalized intracranial mechanical sensitivity of central neurons, but failed to reverse such hypersensitivity in peripheral neurons. In both the peripheral and central neurons, the drug failed to attenuate the increased spontaneous activity established during sensitization. These results suggest that neither peripheral nor central trigeminovascular neurons are directly inhibited by sumatriptan. Rather, triptan action appears to be exerted through presynaptic 5HT1B/1D receptors in the dorsal horn to block synaptic transmission between axon terminals of the peripheral trigeminovascular neurons and cell bodies of their central counterparts. We therefore suggest that the analgesic action of triptan can be attained specifically in the absence, but not in the presence, of central sensitization. PMID:15016917

Disruption of communication between peripheral and central trigeminovascular neurons mediates the antimigraine action of 5HT 1B/1D receptor agonists.

PubMed

Levy, Dan; Jakubowski, Moshe; Burstein, Rami

2004-03-23

Triptans are 5HT(1B/1D) receptor agonists commonly prescribed for migraine headache. Although originally designed to constrict dilated intracranial blood vessels, the mechanism and site of action by which triptans abort the migraine pain remain unknown. We showed recently that sensitization of peripheral and central trigeminovascular neurons plays an important role in the pathophysiology of migraine pain. Here we examined whether the drug sumatriptan can prevent and/or suppress peripheral and central sensitization by using single-unit recording in our animal model of intracranial pain. We found that sumatriptan effectively prevented the induction of sensitization (i.e., increased spontaneous firing; increased neuronal sensitivity to intracranial mechanical stimuli) in central trigeminovascular neurons (recorded in the dorsal horn), but not in peripheral trigeminovascular neurons (recorded in the trigeminal ganglion). After sensitization was established in both types of neuron, sumatriptan effectively normalized intracranial mechanical sensitivity of central neurons, but failed to reverse such hypersensitivity in peripheral neurons. In both the peripheral and central neurons, the drug failed to attenuate the increased spontaneous activity established during sensitization. These results suggest that neither peripheral nor central trigeminovascular neurons are directly inhibited by sumatriptan. Rather, triptan action appears to be exerted through presynaptic 5HT(1B/1D) receptors in the dorsal horn to block synaptic transmission between axon terminals of the peripheral trigeminovascular neurons and cell bodies of their central counterparts. We therefore suggest that the analgesic action of triptan can be attained specifically in the absence, but not in the presence, of central sensitization.

Theoretical Study on Stress Sensitivity of Fractal Porous Media with Irreducible Water

NASA Astrophysics Data System (ADS)

Lei, Gang; Dong, Zhenzhen; Li, Weirong; Wen, Qingzhi; Wang, Cai

The couple flow deformation behavior in porous media has drawn tremendous attention in various scientific and engineering fields. However, though the coupled flow deformation mechanism has been intensively investigated in the last decades, the essential controls on stress sensitivity are not determined. It is of practical significance to use analytic methods to study stress sensitivity of porous media. Unfortunately, because of the disordered and extremely complicated microstructures of porous media, the theoretical model for stress sensitivity is scarce. The goal of this work is to establish a novel and reasonable quantitative model to determine the essential controls on stress sensitivity. The predictions of the theoretical model, derived from the Hertzian contact theory and fractal geometry, agree well with the available experimental data. Compared with the previous models, our model takes into account more factors, including the influence of the water saturation and the microstructural parameters of the pore space. The proposed models can reveal more mechanisms that affect the coupled flow deformation behavior in fractal porous media. The results show that the irreducible water saturation increases with the increase of effective stress, and decreases with the increased rock elastic modulus (or increased power law index) at a given effective stress. The effect of stress variation on porosity is smaller than that on permeability. Under a given effective stress, the normalized permeability (or the normalized porosity) becomes smaller with the decrease of rock elastic modulus (or the decrease of power law index). And a lower capillary pressure will correspond to an increased rock elastic modulus (or an increased power law index) under a given water saturation.

Correlation between algogenic effects of calcitonin-gene-related peptide (CGRP) and activation of trigeminal vascular system, in an in vivo experimental model of nitroglycerin-induced sensitization.

PubMed

Capuano, Alessandro; Greco, Maria Cristina; Navarra, Pierluigi; Tringali, Giuseppe

2014-10-05

The neural mechanism(s) underlying migraine remain poorly defined at present; preclinical and clinical studies show an involvement of CGRP in this disorder. However current evidence pointed out that CGRP does not exert an algogenic action per se, but it is able to mediate migraine pain only if the trigeminal-vascular system is sensitized. The present study was addressed to investigate CGRP-evoked behavior in nitric oxide (NO) sensitized rats, using an experimental model of nitroglycerin induced sensitization of trigeminal system, looking at neuropeptide release from different cerebral areas after the intra-peritoneal (i.p.) administration of NO-donors. CGRP injected into the rat whisker pad did not induce significant changes in face rubbing behavior compared to controls. On the contrary, CGRP injected in animals pre-treated with 10mg/kg nitroglycerin significantly increased the time spent in face rubbing. Nitroglycerin pre-treated animals did not show any rubbing behavior after locally injected saline. Furthermore, the i.p. treatment with nitroglycerin produced an increase of CGRP levels in brainstem and trigeminal ganglia, but not in the hypothalamus and hippocampus. The absolute amounts of CGRP produced in the brainstem were lower compared to those in the trigeminal ganglion; however, after nitroglycerin stimulation the percentage increase was higher in the brainstem. In conclusion, findings presented in this study suggest that CGRP induces a painful behavior in rats only after sensitization of trigeminal system; thus supporting the concept that a genetic as well as acquired predisposition to trigemino- vascular activation represents the neurobiological basis of CGRP nociceptive effects in migraineurs. Copyright © 2014 Elsevier B.V. All rights reserved.

Constitutive Lck Activity Drives Sensitivity Differences between CD8+ Memory T Cell Subsets.

PubMed

Moogk, Duane; Zhong, Shi; Yu, Zhiya; Liadi, Ivan; Rittase, William; Fang, Victoria; Dougherty, Janna; Perez-Garcia, Arianne; Osman, Iman; Zhu, Cheng; Varadarajan, Navin; Restifo, Nicholas P; Frey, Alan B; Krogsgaard, Michelle

2016-07-15

CD8(+) T cells develop increased sensitivity following Ag experience, and differences in sensitivity exist between T cell memory subsets. How differential TCR signaling between memory subsets contributes to sensitivity differences is unclear. We show in mouse effector memory T cells (TEM) that >50% of lymphocyte-specific protein tyrosine kinase (Lck) exists in a constitutively active conformation, compared with <20% in central memory T cells (TCM). Immediately proximal to Lck signaling, we observed enhanced Zap-70 phosphorylation in TEM following TCR ligation compared with TCM Furthermore, we observed superior cytotoxic effector function in TEM compared with TCM, and we provide evidence that this results from a lower probability of TCM reaching threshold signaling owing to the decreased magnitude of TCR-proximal signaling. We provide evidence that the differences in Lck constitutive activity between CD8(+) TCM and TEM are due to differential regulation by SH2 domain-containing phosphatase-1 (Shp-1) and C-terminal Src kinase, and we use modeling of early TCR signaling to reveal the significance of these differences. We show that inhibition of Shp-1 results in increased constitutive Lck activity in TCM to levels similar to TEM, as well as increased cytotoxic effector function in TCM Collectively, this work demonstrates a role for constitutive Lck activity in controlling Ag sensitivity, and it suggests that differential activities of TCR-proximal signaling components may contribute to establishing the divergent effector properties of TCM and TEM. This work also identifies Shp-1 as a potential target to improve the cytotoxic effector functions of TCM for adoptive cell therapy applications. Copyright © 2016 by The American Association of Immunologists, Inc.

Mutation of a single residue in the S2-S3 loop of CNG channels alters the gating properties and sensitivity to inhibitors.

PubMed

Crary, J I; Dean, D M; Maroof, F; Zimmerman, A L

2000-12-01

We previously found that native cyclic nucleotide-gated (CNG) cation channels from amphibian rod cells are directly and reversibly inhibited by analogues of diacylglycerol (DAG), but little is known about the mechanism of this inhibition. We recently determined that, at saturating cGMP concentrations, DAG completely inhibits cloned bovine rod (Brod) CNG channels while only partially inhibiting cloned rat olfactory (Rolf) channels (Crary, J.I., D.M. Dean, W. Nguitragool, P.T. Kurshan, and A.L. Zimmerman. 2000. J. Gen. Phys. 116:755-768; in this issue). Here, we report that a point mutation at position 204 in the S2-S3 loop of Rolf and a mouse CNG channel (Molf) found in olfactory epithelium and heart, increased DAG sensitivity to that of the Brod channel. Mutation of this residue from the wild-type glycine to a glutamate (Molf G204E) or aspartate (Molf G204D) gave dramatic increases in DAG sensitivity without changing the apparent cGMP or cAMP affinities or efficacies. However, unlike the wild-type olfactory channels, these mutants demonstrated voltage-dependent gating with obvious activation and deactivation kinetics. Interestingly, the mutants were also more sensitive to inhibition by the local anesthetic, tetracaine. Replacement of the position 204 glycine with a tryptophan residue (Rolf G204W) not only gave voltage-dependent gating and an increased sensitivity to DAG and tetracaine, but also showed reduced apparent agonist affinity and cAMP efficacy. Sequence comparisons show that the glycine at position 204 in the S2-S3 loop is highly conserved, and our findings indicate that its alteration can have critical consequences for channel gating and inhibition.

Detection of fibrin generation alterations in dogs with haemangiosarcoma using resonance thrombography.

PubMed

Mischke, R; Wohlsein, P; Schoon, H-A

2005-01-01

The objective of the study was to examine the alterations of fibrin generation in dogs with haemangiosarcoma using resonance thrombography. The second objective was to evaluate the sensitivity of this method for the detection of hypofibrinogenaemia and/or increased fibrin(ogen) degradation product (FDP) concentration. Resonance thrombogram (RTG) measurements with two different instruments were performed in 30 unselected dogs with haemangiosarcoma, 14 of which had decreased fibrinogen and 28 of which had an increased FDP concentration (p<0.0001). The RTG-reaction time was less sensitive than the fibrin formation time (RTG-f) and fibrin amplitude (RTG-F). The RTG-f and RTG-F indicated reliably a decrease in fibrinogen concentration (sensitivity: 0.93). The sensitivity of detection of increased FDP levels was considerably higher than that of thrombin time. However, false-negative results were found even at FDP concentrations > or =120 mg/l, especially in cases with high fibrinogen level. Both machines showed similar sensitivity. The results of this study indicate that canine haemangiosarcoma is frequently associated with severe alterations of fibrin generation due to low fibrinogen and high FDP levels leading to distinct RTG abnormalities. The global test RTG reacts sensitively to a decreased fibrinogen level whereas its accuracy to detect FDP concentrations occurring under pathophysiological conditions is limited. A significant alteration of fibrin generation induced by FDPs may not occur until the serum FDP concentration exceeds 60 mg/l.

Anxiety, its relation to symptoms severity and anxiety sensitivity in sarcoidosis.

PubMed

Holas, Pawel; Krejtz, Izabela; Urbankowski, Tomasz; Skowyra, Artur; Ludwiniak, Anna; Domagala-Kulawik, Joanna

2013-12-17

Sarcoidosis is a chronic systemic granulomatous disease of unknown etiology. Previous studies demonstrated that patients with sarcoidosis had high rates of depression and anxiety, and high magnitude of stressful life events. To date, however, studies have not examined the anxiety sensitivity in sarcoid patients and the relationship between psychopathology and symptom severity of sarcoidosis.The aims of this study were to evaluate prevalence of depression and anxiety in sarcoid patients, to assess their relationship with the disease symptom severity, and to investigate the relationship between sarcoidosis and anxiety sensitivity. Thirty three sarcoid patients and thirty three control subjects completed the following:Hospital Anxiety and Depression Scale, Anxiety Sensitivity Index-3. The prevalence of depression (29%) and anxiety (31%) was high among patients and comparable to results from other research groups. Anxiety was significantly correlated with symptom severity and was the main covariate of physical symptoms reported by sarcoid patients. Patients exhibited an increase of their total anxiety sensitivity index and had an increased number of physical concerns. These data confirmed earlier reports that anxiety and depression are common in patients with sarcoidosis and expanded on the previous results by showing that patients exhibited increased anxiety sensitivity and a fear of physical sensations. These results, together with the findings that anxiety was associated with sarcoidosis symptom severity, suggest that targeting anxiety and the physical health concerns may be important in the diagnosis and management of this disease.

Comparison of the diagnostic ability of Moorfield’s regression analysis and glaucoma probability score using Heidelberg retinal tomograph III in eyes with primary open angle glaucoma

PubMed Central

Jindal, Shveta; Dada, Tanuj; Sreenivas, V; Gupta, Viney; Sihota, Ramanjit; Panda, Anita

2010-01-01

Purpose: To compare the diagnostic performance of the Heidelberg retinal tomograph (HRT) glaucoma probability score (GPS) with that of Moorfield’s regression analysis (MRA). Materials and Methods: The study included 50 eyes of normal subjects and 50 eyes of subjects with early-to-moderate primary open angle glaucoma. Images were obtained by using HRT version 3.0. Results: The agreement coefficient (weighted k) for the overall MRA and GPS classification was 0.216 (95% CI: 0.119 – 0.315). The sensitivity and specificity were evaluated using the most specific (borderline results included as test negatives) and least specific criteria (borderline results included as test positives). The MRA sensitivity and specificity were 30.61 and 98% (most specific) and 57.14 and 98% (least specific). The GPS sensitivity and specificity were 81.63 and 73.47% (most specific) and 95.92 and 34.69% (least specific). The MRA gave a higher positive likelihood ratio (28.57 vs. 3.08) and the GPS gave a higher negative likelihood ratio (0.25 vs. 0.44).The sensitivity increased with increasing disc size for both MRA and GPS. Conclusions: There was a poor agreement between the overall MRA and GPS classifications. GPS tended to have higher sensitivities, lower specificities, and lower likelihood ratios than the MRA. The disc size should be taken into consideration when interpreting the results of HRT, as both the GPS and MRA showed decreased sensitivity for smaller discs and the GPS showed decreased specificity for larger discs. PMID:20952832

Development of a high-sensitivity strain measurement system based on a SH SAW sensor

NASA Astrophysics Data System (ADS)

Oh, Haekwan; Lee, Keekeun; Eun, Kyoungtae; Choa, Sung-Hoon; Yang, Sang Sik

2012-02-01

A strain measurement system based on a shear horizontal surface acoustic wave (SH SAW) was developed. The developed system is composed of a SAW microsensor, a printed circuit board (PCB), an adhesive and a strain gauge. When a compression force is applied to the PCB by the strain gauge, the PCB is bent so that external strain energy can be evenly delivered to the microsensor without any detachment of the sensor from the board. When a stretching force is applied to the PCB under the condition that one side of the PCB is fixed and the other side is modulated, the actual length of the SAW delay line between the two interdigital transducers (IDTs) is increased. The increase in the delay line length causes a change in the time for the propagating SAW to reach the output IDT. If strain energy is applied to the piezoelectric substrate, the substrate density is changed, which then changes the propagation velocity of the SAW. Coupling-of-modes modeling was conducted prior to fabrication to determine the optimal device parameters. Depending on the strain, the frequency difference was linearly modulated. The obtained sensitivity for stretching was 17.3 kHz/% for the SH wave mode and split electrode. And the obtained sensitivity for bending was 46.1 kHz/% for the SH wave mode and split electrode. The SH wave showed about 15% higher sensitivity than the Rayleigh wave, and the dog-bone PCB showed about 8% higher sensitivity than the rectangular PCB. The obtained sensitivity was about five times higher than that of existing SAW-based strain sensors.

Effect of body weight gain on insulin sensitivity after retirement from exercise training

NASA Technical Reports Server (NTRS)

Dolkas, Constantine B.; Rodnick, Kenneth J.; Mondon, Carl E.

1990-01-01

The effect of the body-weight gain after retirement from an exercise-training program on the retained increase in insulin sensitivity elicited by the training was investigated in exercise-trained (ET) rats. Insulin sensitivity was assessed by oral glucose tolerance and insulin suppression tests immediately after training and during retirement. Results show that, compared with sedentary controls, exercise training enhanced insulin-induced glucose uptake, but the enhanced sensitivity was gradually lost with the end of running activity until after seven days of retirement, when it became equal to that of controls. This loss of enhanced sensitivity to insulin was associated with an accelerated gain in body weight beginning one day after the start of retirement. However, those animals that gained weight only at rates similar to those of control rats, retained their enhanced sensitivity to insulin.

Three-dimensional solutions for the thermal buckling and sensitivity derivatives of temperature-sensitive multilayered angle-ply plates

NASA Technical Reports Server (NTRS)

Noor, A. K.; Burton, W. S.

1992-01-01

Analytic three-dimensional thermoelasticity solutions are presented for the thermal buckling of multilayered angle-ply composite plates with temperature-dependent thermoelastic properties. Both the critical temperatures and the sensitivity derivatives are computed. The sensitivity derivatives measure the sensitivity of the buckling response to variations in the different lamination and material parameters of the plate. The plates are assumed to have rectangular geometry and an antisymmetric lamination with respect to the middle plane. The temperature is assumed to be independent of the surface coordinates, but has an arbitrary symmetric variation through the thickness of the plate. The prebuckling deformations are accounted for. Numerical results are presented, for plates subjected to uniform temperature increase, showing the effects of temperature-dependent material properties on the prebuckling stresses, critical temperatures, and their sensitivity derivatives.

Assessment of the sensitizing potency of preservatives with chance of skin contact by the loose-fit coculture-based sensitization assay (LCSA).

PubMed

Sonnenburg, Anna; Schreiner, Maximilian; Stahlmann, Ralf

2015-12-01

Parabens, methylisothiazolinone (MI) and its derivative methylchloroisothiazolinone (MCI), are commonly used as preservatives in personal care products. They can cause hypersensitivity reactions of the human skin. We have tested a set of nine parabens, MI alone and in combination with MCI in the loose-fit coculture-based sensitization assay (LCSA). The coculture of primary human keratinocytes and allogenic dendritic cell-related cells (DC-rc) in this assay emulates the in vivo situation of the human skin. Sensitization potency of the test substances was assessed by flow cytometric analysis of the DC-rc maturation marker CD86. Determination of the concentration required to cause a half-maximal increase in CD86-expression (EC50sens) allowed a quantitative evaluation. The cytotoxicity of test substances as indicator for irritative potency was measured by 7-AAD (7-amino-actinomycin D) staining. Parabens exhibited weak (methyl-, ethyl-, propyl- and isopropylparaben) or strong (butyl-, isobutyl-, pentyl- and benzylparaben) effects, whereas phenylparaben was found to be a moderate sensitizer. Sensitization potencies of parabens correlated with side chain length. Due to a pronounced cytotoxicity, we could not estimate an EC50sens value for MI, whereas MI/MCI was classified as sensitizer and also showed cytotoxic effects. Parabens showed no (methyl- and ethylparaben) or weak irritative potencies (propyl-, isopropyl-, butyl-, isobutyl-, phenyl- and benzylparaben), only pentylparaben was rated to be irritative. Overall, we were able to demonstrate and compare the sensitizing potencies of parabens in this in vitro test. Furthermore, we showed an irritative potency for most of the preservatives. The data further support the usefulness of the LCSA for comparison of the sensitizing potencies of xenobiotics.

Sense and sensitivity: responsiveness to offspring signals varies with the parents' potential to breed again

PubMed Central

Thorogood, Rose; Ewen, John G.; Kilner, Rebecca M.

2011-01-01

How sensitive should parents be to the demands of their young? Offspring are under selection to seek more investment than is optimal for parents to supply, which makes parents vulnerable to losing future fitness by responding to manipulative displays. Yet, parents cannot afford to ignore begging and risk allocating resources inefficiently. Here, we show that parents may solve this problem by adjusting their sensitivity to begging behaviour in relation to their own likelihood of breeding again, a factor largely neglected in previous analyses of parent–offspring interactions. In two carotenoid-supplementation experiments on a New Zealand passerine, the hihi Notiomystis cincta, we supplemented adults to enhance their propensity to breed again, and supplemented entire broods to increase their mouth colour, thus enhancing their solicitation display. We found that adults that attempted two breeding attempts a season were largely insensitive to the experimentally carotenoid-rich gapes of their brood, whereas those that bred just once responded by increasing their rate of provisioning at the nest. Our results show that parents can strategically vary their sensitivity to begging in relation to their future reproductive potential. By restricting opportunities for offspring to influence provisioning decisions, parents greatly limit the potential for offspring to win parent–offspring conflict. PMID:21270035

[Dendrochronology of Chinese pine in Mulan-Weichang, Hebei Province: a primary study].

PubMed

Cui, Ming-xing; He, Xing-yuan; Chen, Wei; Chen, Zhen-ju; Zhou, Chang-hong; Wu, Tao

2008-11-01

Dendroclimatic methods were used to investigate the relationships between the growth of Chinese pine (Pinus tabulaeformis Carr.) and the climatic parameters in Mulan-Weichang of Hebei Province. The results showed that Chinese pine presented high sensitivity to climatic changes, and its earlywood width showed the highest sensitivity. There was a significant negative correlation between the tree-ring width chronology of Chinese pine and the air temperature in May-June. The precipitation and relative humidity in June had strong positive effects on the growth of earlywood, the precipitation from September to next September had significant positive effects on Chinese pine growth, and the relative humidity in winter more strongly affected the growth of latewood than of earlywood. There was a definite correlation between the tree-ring width chronology of Chinese pine and the large scale climate fluctuation. From 1951 to 2006, the increase of air temperature in study area was significant, and the sensitivity of Chinese pine to the variations of local temperature and precipitation decreased, presenting an inverse transforming trend with increasing temperature. Greater differences were observed between the reconstructed and observed data of mean temperature in May - June in a century scale, suggesting that the tree-ring growth of Chinese pine in study area had a greater fluctuation of sensitivity to the variation of climatic factors.

Synthesis and in vitro antifungal efficacy of oleoyl-chitosan nanoparticles against plant pathogenic fungi.

PubMed

Xing, Ke; Shen, Xiaoqiang; Zhu, Xiao; Ju, Xiuyun; Miao, Xiangmin; Tian, Jun; Feng, Zhaozhong; Peng, Xue; Jiang, Jihong; Qin, Sheng

2016-01-01

An antifungal dispersion system was prepared by oleoyl-chitosan (O-chitosan) nanoparticles, and the antifungal activity against several plant pathogenic fungi was investigated. Under scanning electron microscopy, the nanoparticles formulation appeared to be uniform with almost spherical shape. The particle size of nanoparticles was around 296.962 nm. Transmission electron microscopy observation showed that nanoparticles could be well distributed in potato dextrose agar medium. Mycelium growth experiment demonstrated that Nigrospora sphaerica, Botryosphaeria dothidea, Nigrospora oryzae and Alternaria tenuissima were chitosan-sensitive, while Gibberella zeae and Fusarium culmorum were chitosan-resistant. The antifungal index was increased as the concentration of nanoparticles increased for chitosan-sensitive fungi. Fatty acid analyses revealed that plasma membranes of chitosan-sensitive fungi were shown to have lower levels of unsaturated fatty acid than chitosan-resistant fungi. Phylogenetic analysis based on ITS gene sequences indicated that two chitosan-resistant fungi had a near phylogenetic relationship. Results showed that O-chitosan nanoparticles could be a useful alternative for controlling pathogenic fungi in agriculture. Copyright © 2015 Elsevier B.V. All rights reserved.

What constitutes food variety? Stimulus specificity of food.

PubMed

Epstein, Leonard H; Robinson, Jodie L; Roemmich, James N; Marusewski, Angela L; Roba, Lora G

2010-02-01

Variety is a major influence of energy intake, but it is not known how much foods have to vary to influence eating. Using a stimulus specificity habituation paradigm we assessed the influence of varying the texture and appearance of nutritionally identical foods on responding for food and energy intake, and whether sensitization, or an increase in responding prior to habituation, was related to the rate of habituation or recovery of responding. Children responded for elbow macaroni and cheese until they habituated, then were provided either more elbow macaroni and cheese, spiral macaroni and cheese, or chicken nuggets. Children provided chicken nuggets or spiral macaroni and cheese recovered responding in comparison to more elbow macaroni and cheese. Children who sensitized showed slower habituation and consumed more food and more energy than those who did not sensitize, but did not differ in recovery of responding to the chicken nuggets or spiral macaroni and cheese. Results show small variations in food characteristics lead to recovery of responding and increased intake after children have habituated. 2009 Elsevier Ltd. All rights reserved.

Comparing the usefulness of the 1997 and 2009 WHO dengue case classification: a systematic literature review.

PubMed

Horstick, Olaf; Jaenisch, Thomas; Martinez, Eric; Kroeger, Axel; See, Lucy Lum Chai; Farrar, Jeremy; Ranzinger, Silvia Runge

2014-09-01

The 1997 and 2009 WHO dengue case classifications were compared in a systematic review with 12 eligible studies (4 prospective). Ten expert opinion articles were used for discussion. For the 2009 WHO classification studies show: when determining severe dengue sensitivity ranges between 59-98% (88%/98%: prospective studies), specificity between 41-99% (99%: prospective study) - comparing the 1997 WHO classification: sensitivity 24.8-89.9% (24.8%/74%: prospective studies), specificity: 25%/100% (100%: prospective study). The application of the 2009 WHO classification is easy, however for (non-severe) dengue there may be a risk of monitoring increased case numbers. Warning signs validation studies are needed. For epidemiological/pathogenesis research use of the 2009 WHO classification, opinion papers show that ease of application, increased sensitivity (severe dengue) and international comparability are advantageous; 3 severe dengue criteria (severe plasma leakage, severe bleeding, severe organ manifestation) are useful research endpoints. The 2009 WHO classification has clear advantages for clinical use, use in epidemiology is promising and research use may at least not be a disadvantage. © The American Society of Tropical Medicine and Hygiene.

Gingerol sensitizes TRAIL-induced apoptotic cell death of glioblastoma cells

PubMed Central

Lee, Dae-Hee; Kim, Dong-Wook; Jung, Chang-Hwa; Lee, Yong J.; Park, Daeho

2014-01-01

Glioblastoma multiforme (GBM) is the most lethal and aggressive astrocytoma of primary brain tumors in adults. Although there are many clinical trials to induce the cell death of glioblastoma cells, most glioblastoma cells have been reported to be resistant to TRAIL-induced apoptosis. Here, we showed that gingerol as a major component of ginger can induce TRAIL-mediated apoptosis of glioblastoma. Gingerol increased death receptor (DR) 5 levels in a p53-dependent manner. Furthermore, gingerol decreased the expression level of anti-apoptotic proteins (survivin, c-FLIP, Bcl-2, and XIAP) and increased pro-apoptotic protein, Bax and truncate Bid, by generating reactive oxygen species (ROS).We also found that the sensitizing effects of gingerol in TRAIL-induced cell death were blocked by scavenging ROS or overexpressing anti-apoptotic protein (Bcl-2). Therefore, we showed the functions of gingerol as a sensitizing agent to induce cell death of TRAIL-resistant glioblastoma cells. This study gives rise to the possibility of applying gingerol as an anti-tumor agent that can be used for the purpose of combination treatment with TRAIL in TRAIL-resistant glioblastoma tumor therapy. PMID:25034532

Culture and drug sensitivity testing among patients with pulmonary tuberculosis in Mexico: national data for 2009-2013.

PubMed

Orejel, Ivonne; Castellanos, Martin; Marín, Diana; Mendoza, Alberto; Harries, Anthony D

2016-01-01

This study documented the number and results of mycobacterial culture and drug sensitivity testing (CDST) in Mexico from 2009-2013 and assessed whether states with a higher risk of multidrug-resistant tuberculosis (MDR-TB) performed more CDST and had more cultures showing MDR-TB. Data for this longitudinal, descriptive, operational research study came from the electronic records of 31 state public health laboratories in Mexico. The total number of CDSTs was 6 470, increasing from 2 143 in the first 2 years to 4 327 in the latter 3 years. There was a significant increase in the proportion of cultures showing sensitivity to all drugs, from 53.1% to 60.9% in 2011-2013 (P < 0.001) and a significant decrease in the proportion showing MDR-TB, from 28.2% in 2009 to 19.8% in 2013 (P < 0.001). Cases of extensively drug resistant tuberculosis were < 1% per year. In the 12 states with higher risk for MDR-TB, significantly more CDSTs (2 382 test) were done in 2011-2013 than in the other 19 states (1 945 tests). Also, for each year the proportion of cultures showing MDR-TB was significantly higher in high risk MDR-TB states than in lower risk ones (P < 0.001). During the 5-year study period, CDST was scaled up in Mexico, particularly in high-risk MDR-TB states where a higher proportion of cultures showed MDR-TB. Scale up and wider coverage of CDST should continue.

The development of basic taste sensitivity and preferences in children.

PubMed

Fry Vennerød, Frida Felicia; Nicklaus, Sophie; Lien, Nanna; Almli, Valérie L

2018-08-01

This study aims at understanding how preference and sensitivity to the basic tastes develop in the preschool years, and how the two relate to each other. To expand on the existing literature regarding taste preferences conducted in cross-sectional studies, a longitudinal design was applied with children from age four to six years old. During the springs of 2015, 2016, and 2017, 131 children born in 2011 were tested in their kindergartens. To investigate preferences for sweet, sour and bitter tastes, the children performed ranking-by-elimination procedures on fruit-flavored beverages and chocolates with three taste intensity levels. The beverages varied in either sucrose, citric acid, or the bitter component isolone. The chocolates varied in the bitter component theobromine from cocoa and sucrose content. Each year, the children also performed paired-comparison tasks opposing plain water to tastant dilutions at four concentrations. The stimuli consisted of the five basic tastes: sweet (sucrose) sour (citric acid monohydrate) umami (monosodium glutamate), salty (sodium chloride), and bitter (quinine hydrochloride dihydrate). Preference for sweetness levels increased with age, while preference for bitterness and sourness levels were stable. Concerning taste sensitivity, the children showed an increase in sensitivity for sourness and saltiness, a decrease for sweetness, and stability for umami and bitterness. A negative association was found between sweetness sensitivity and preference for sweetness. The study highlights different trajectories of sensitivity and preferences across tastes. On average, a reduction in sweetness sensitivity combined with an increase in preference for higher sweetness was observed from the age of four to six. The weak relationship between taste sensitivity and taste preference in our data suggests that taste preference development is shaped by a multitude of factors in addition to taste sensitivity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Aortic Baroreceptors Display Higher Mechanosensitivity than Carotid Baroreceptors.

PubMed

Lau, Eva On-Chai; Lo, Chun-Yin; Yao, Yifei; Mak, Arthur Fuk-Tat; Jiang, Liwen; Huang, Yu; Yao, Xiaoqiang

2016-01-01

Arterial baroreceptors are mechanical sensors that detect blood pressure changes. It has long been suggested that the two arterial baroreceptors, aortic and carotid baroreceptors, have different pressure sensitivities. However, there is no consensus as to which of the arterial baroreceptors are more sensitive to changes in blood pressure. In the present study, we employed independent methods to compare the pressure sensitivity of the two arterial baroreceptors. Firstly, pressure-activated action potential firing was measured by whole-cell current clamp with a high-speed pressure clamp system in primary cultured baroreceptor neurons. The results show that aortic depressor neurons possessed a higher percentage of mechano-sensitive neurons. Furthermore, aortic baroreceptor neurons show a lower pressure threshold than that of carotid baroreceptor neurons. Secondly, uniaxial stretching of baroreceptor neurons, that mimics the forces exerted on blood vessels, elicited a larger increase in intracellular Ca(2+) rise in aortic baroreceptor neurons than in carotid baroreceptor neurons. Thirdly, the pressure-induced action potential firing in the aortic depressor nerve recorded in vivo was also higher. The present study therefore provides for a basic physiological understanding on the pressure sensitivity of the two baroreceptor neurons and suggests that aortic baroreceptors have a higher pressure sensitivity than carotid baroreceptors.

Increased sensitivity of prolonged P-wave during exercise stress test in detection of angiographically documented coronary artery disease.

PubMed

Wsol, Agnieszka; Wydra, Wioletta; Chmielewski, Marek; Swiatowiec, Andrzej; Kuch, Marek

2017-01-01

A retrospective study was designed to investigate P-wave duration changes in exercise stress test (EST) for the prediction of angiographically documented substantial coronary artery disease (CAD). We analyzed 265 cases of patients, who underwent EST and subsequently coronary angiography. Analysis of P-wave duration was performed in leads II, V5 at rest, and in the recovery period. The sensitivity and specificity for the isolated ST-segment depression were only 31% and 76%, respectively. The combination of ST-depression with other exercise-induced clinical and electrocardio-graphic abnormalities (chest pain, ventricular arrhythmia, hypotension, left bundle branch block) was characterized by 41% sensitivity and 69% specificity. The combination of abnormal recovery P-wave duration (≥ 120 ms) with ST-depression and other exercise-induced abnormalities had 83% sensitivity but only 20% specificity. Combined analysis of increased delta P-wave duration, ST-depression and other exercise-induced abnormalities had 69% sensitivity and 42% specificity. Sensitivity and specificity of the increase in delta P-wave duration for left CAD was 69% and 47%, respectively, and for 3-vessel CAD 70% and 50%, respectively. The presence of arterial hypertension negatively influenced the prog-nostic value of P-wave changes in the stress test. The results of the study show that an addition of P-wave duration changes assessment to ST-depression analysis and other exercise-induced abnormalities increase sensitivity of EST, especially for left CAD and 3-vessel coronary disease. We have also provided evidence for the negative influence of the presence of arterial hypertension on the predictive value of P-wave changes in the stress test. (Cardiol J 2017; 24, 2: 159-166).

Skin sensitizers differentially regulate signaling pathways in MUTZ-3 cells in relation to their individual potency

PubMed Central

2014-01-01

Background Due to the recent European legislations posing a ban of animal tests for safety assessment within the cosmetic industry, development of in vitro alternatives for assessment of skin sensitization is highly prioritized. To date, proposed in vitro assays are mainly based on single biomarkers, which so far have not been able to classify and stratify chemicals into subgroups, related to risk or potency. Methods Recently, we presented the Genomic Allergen Rapid Detection (GARD) assay for assessment of chemical sensitizers. In this paper, we show how the genome wide readout of GARD can be expanded and used to identify differentially regulated pathways relating to individual chemical sensitizers. In this study, we investigated the mechanisms of action of a range of skin sensitizers through pathway identification, pathway classification and transcription factor analysis and related this to the reactive mechanisms and potency of the sensitizing agents. Results By transcriptional profiling of chemically stimulated MUTZ-3 cells, 33 canonical pathways intimately involved in sensitization to chemical substances were identified. The results showed that metabolic processes, cell cycling and oxidative stress responses are the key events activated during skin sensitization, and that these functions are engaged differently depending on the reactivity mechanisms of the sensitizing agent. Furthermore, the results indicate that the chemical reactivity groups seem to gradually engage more pathways and more molecules in each pathway with increasing sensitizing potency of the chemical used for stimulation. Also, a switch in gene regulation from up to down regulation, with increasing potency, was seen both in genes involved in metabolic functions and cell cycling. These observed pathway patterns were clearly reflected in the regulatory elements identified to drive these processes, where 33 regulatory elements have been proposed for further analysis. Conclusions This study demonstrates that functional analysis of biomarkers identified from our genomics study of human MUTZ-3 cells can be used to assess sensitizing potency of chemicals in vitro, by the identification of key cellular events, such as metabolic and cell cycling pathways. PMID:24517095

Determination of the effects of water adsorption on the sensitivity and detonation performance of the explosive JOB-9003 by molecular dynamics simulation.

PubMed

Hang, GuiYun; Yu, WenLi; Wang, Tao; Li, Zhen

2016-11-01

In order to determine the adsorption mechanism of water on the crystal surfaces of the explosive JOB-9003 and the effect of this adsorption on the sensitivity and detonation performance of this explosive, a model of the crystal of JOB-9003 was created in the software package Materials Studio (MS). The adsorption process was simulated, and molecular dynamics simulation was performed with the COMPASS force field in the NPT ensemble to calculate the sensitivity and detonation performance of the explosive. The results show that the maximum trigger bond length decreases whereas the interaction energy of the trigger bond and the cohesive energy density increase after adsorption, indicating that the sensitivity of JOB-9003 decreases. The results for the detonation performance show that the detonation pressure, detonation velocity, and detonation heat decrease upon the adsorption of water, thus illustrating that the detonation performance of JOB-9003 is degraded. In summary, the adsorption of water has a positive effect on the sensitivity and safety of the explosive JOB-9003 but a negative effect on its detonation performance.

Tuning the Sensitivity of an Optical Cavity with Slow and Fast Light

NASA Technical Reports Server (NTRS)

Smith, David D.; Myneni, Krishna; Chang, H.; Toftul, A.; Schambeau, C.; Odutola, J. A.; Diels, J. C.

2012-01-01

We have measured mode pushing by the dispersion of a rubidium vapor in a Fabry-Perot cavity and have shown that the scale factor and sensitivity of a passive cavity can be strongly enhanced by the presence of such an anomalous dispersion medium. The enhancement is the result of the atom-cavity coupling, which provides a positive feedback to the cavity response. The cavity sensitivity can also be controlled and tuned through a pole by a second, optical pumping, beam applied transverse to the cavity. Alternatively, the sensitivity can be controlled by the introduction of a second counter-propagating input beam that interferes with the first beam, coherently increasing the cavity absorptance. We show that the pole in the sensitivity occurs when the sum of the effective group index and an additional cavity delay factor that accounts for mode reshaping goes to zero, and is an example of an exceptional point, commonly associated with coupled non-Hermitian Hamiltonian systems. Additionally we show that a normal dispersion feature can decrease the cavity scale factor and can be generated through velocity selective optical pumping

Sensitivity of LES results from turbine rim seals to changes in grid resolution and sector size

NASA Astrophysics Data System (ADS)

O'Mahoney, T.; Hills, N.; Chew, J.

2012-07-01

Large-Eddy Simulations (LES) were carried out for a turbine rim seal and the sensitivity of the results to changes in grid resolution and the size of the computational domain are investigated. Ingestion of hot annulus gas into the rotor-stator cavity is compared between LES results and against experiments and Unsteady Reynolds-Averaged Navier-Stokes (URANS) calculations. The LES calculations show greater ingestion than the URANS calculation and show better agreement with experiments. Increased grid resolution shows a small improvement in ingestion predictions whereas increasing the sector model size has little effect on the results. The contrast between the different CFD models is most stark in the inner cavity, where the URANS shows almost no ingestion. Particular attention is also paid to the presence of low frequency oscillations in the disc cavity. URANS calculations show such low frequency oscillations at different frequencies than the LES. The oscillations also take a very long time to develop in the LES. The results show that the difficult problem of estimating ingestion through rim seals could be overcome by using LES but that the computational requirements were still restrictive.

The association of noise sensitivity with music listening, training, and aptitude

PubMed Central

Kliuchko, Marina; Heinonen-Guzejev, Marja; Monacis, Lucia; Gold, Benjamin P.; Heikkilä, Kauko V.; Spinosa, Vittoria; Tervaniemi, Mari; Brattico, Elvira

2015-01-01

After intensive, long-term musical training, the auditory system of a musician is specifically tuned to perceive musical sounds. We wished to find out whether a musician's auditory system also develops increased sensitivity to any sound of everyday life, experiencing them as noise. For this purpose, an online survey, including questionnaires on noise sensitivity, musical background, and listening tests for assessing musical aptitude, was administered to 197 participants in Finland and Italy. Subjective noise sensitivity (assessed with the Weinstein's Noise Sensitivity Scale) was analyzed for associations with musicianship, musical aptitude, weekly time spent listening to music, and the importance of music in each person's life (or music importance). Subjects were divided into three groups according to their musical expertise: Nonmusicians (N = 103), amateur musicians (N = 44), and professional musicians (N = 50). The results showed that noise sensitivity did not depend on musical expertise or performance on musicality tests or the amount of active (attentive) listening to music. In contrast, it was associated with daily passive listening to music, so that individuals with higher noise sensitivity spent less time in passive (background) listening to music than those with lower sensitivity to noise. Furthermore, noise-sensitive respondents rated music as less important in their life than did individuals with lower sensitivity to noise. The results demonstrate that the special sensitivity of the auditory system derived from musical training does not lead to increased irritability from unwanted sounds. However, the disposition to tolerate contingent musical backgrounds in everyday life depends on the individual's noise sensitivity. PMID:26356378

Carboxylated hyperbranched poly(glycidol)s for preparation of pH-sensitive liposomes.

PubMed

Yuba, Eiji; Harada, Atsushi; Sakanishi, Yuichi; Kono, Kenji

2011-01-05

Previous reports by the authors described intracellular delivery using liposomes modified with various carboxylated poly(glycidol) derivatives. These linear polymer-modified liposomes exhibited a pH-dependent membrane fusion behavior in cellular acidic compartments. However, the effect of the backbone structure on membrane fusion activity remains unknown. Therefore, this study specifically investigated the backbone structure to obtain pH-sensitive polymers with much higher fusogenic activity and to reveal the effect of the polymer backbone structure on the interaction with the membrane. Hyperbranched poly(glycidol) (HPG) derivatives were prepared as a new type of pH-sensitive polymer and used for the modification of liposomes. The resultant HPG derivatives exhibited high hydrophobicity and intensive interaction with the membrane concomitantly with the increasing degree of polymerization (DP). Furthermore, HPG derivatives showed a stronger interaction with the membrane than the linear polymers show. Liposomes modified with HPG derivatives of high DP delivered contents into the cytosol of DC2.4 cells, a dendritic cell line, more effectively than the linear polymer-modified liposomes do. Results show that the backbone structure of pH-sensitive polymers affected their pH-sensitivity and interaction with liposomal and cellular membranes. Copyright © 2010 Elsevier B.V. All rights reserved.

Spectrum and Sensitivity of Bacterial Keratitis Isolates in Auckland.

PubMed

Marasini, S; Swift, S; Dean, S J; Ormonde, S E; Craig, J P

2016-01-01

Background. The bacteria isolated from severe cases of keratitis and their antibiotic sensitivity are recognised to vary geographically and over time. Objectives. To identify the most commonly isolated bacteria in keratitis cases admitted over a 24-month period to a public hospital in Auckland, New Zealand, and to investigate in vitro sensitivity to antibiotics. Methods. Hospital admissions for culture-proven bacterial keratitis between January 2013 and December 2014 were identified. Laboratory records of 89 culture positive cases were retrospectively reviewed and antibiotic sensitivity patterns compared with previous studies from other NZ centres. Results. From 126 positive cultures, 35 species were identified. Staphylococcus was identified to be the most common isolate (38.2%), followed by Pseudomonas (21.3%). Over the last decade, infection due to Pseudomonas species, in the same setting, has increased (p ≤ 0.05). Aminoglycosides, cefazolin, ceftazidime, erythromycin, tetracycline, and doxycycline were 100% effective against tested isolates in vitro. Amoxicillin (41.6%), cefuroxime (33.3%), and chloramphenicol (94.7%) showed reduced efficacy against Gram-negative bacteria, whereas penicillin (51%) and ciprofloxacin (98.8%) showed reduced efficacy against Gram-positive bacteria. Conclusions. Despite a shift in the spectrum of bacterial keratitis isolates, antibiotic sensitivity patterns have generally remained stable and show comparability to results within the last decade from NZ centres.

Spectrum and Sensitivity of Bacterial Keratitis Isolates in Auckland

PubMed Central

Swift, S.; Dean, S. J.; Ormonde, S. E.

2016-01-01

Background. The bacteria isolated from severe cases of keratitis and their antibiotic sensitivity are recognised to vary geographically and over time. Objectives. To identify the most commonly isolated bacteria in keratitis cases admitted over a 24-month period to a public hospital in Auckland, New Zealand, and to investigate in vitro sensitivity to antibiotics. Methods. Hospital admissions for culture-proven bacterial keratitis between January 2013 and December 2014 were identified. Laboratory records of 89 culture positive cases were retrospectively reviewed and antibiotic sensitivity patterns compared with previous studies from other NZ centres. Results. From 126 positive cultures, 35 species were identified. Staphylococcus was identified to be the most common isolate (38.2%), followed by Pseudomonas (21.3%). Over the last decade, infection due to Pseudomonas species, in the same setting, has increased (p ≤ 0.05). Aminoglycosides, cefazolin, ceftazidime, erythromycin, tetracycline, and doxycycline were 100% effective against tested isolates in vitro. Amoxicillin (41.6%), cefuroxime (33.3%), and chloramphenicol (94.7%) showed reduced efficacy against Gram-negative bacteria, whereas penicillin (51%) and ciprofloxacin (98.8%) showed reduced efficacy against Gram-positive bacteria. Conclusions. Despite a shift in the spectrum of bacterial keratitis isolates, antibiotic sensitivity patterns have generally remained stable and show comparability to results within the last decade from NZ centres. PMID:27213052

The development of cortical sensitivity to visual word forms.

PubMed

Ben-Shachar, Michal; Dougherty, Robert F; Deutsch, Gayle K; Wandell, Brian A

2011-09-01

The ability to extract visual word forms quickly and efficiently is essential for using reading as a tool for learning. We describe the first longitudinal fMRI study to chart individual changes in cortical sensitivity to written words as reading develops. We conducted four annual measurements of brain function and reading skills in a heterogeneous group of children, initially 7-12 years old. The results show age-related increase in children's cortical sensitivity to word visibility in posterior left occipito-temporal sulcus (LOTS), nearby the anatomical location of the visual word form area. Moreover, the rate of increase in LOTS word sensitivity specifically correlates with the rate of improvement in sight word efficiency, a measure of speeded overt word reading. Other cortical regions, including V1, posterior parietal cortex, and the right homologue of LOTS, did not demonstrate such developmental changes. These results provide developmental support for the hypothesis that LOTS is part of the cortical circuitry that extracts visual word forms quickly and efficiently and highlight the importance of developing cortical sensitivity to word visibility in reading acquisition.

Experimental study on the influence of chemical sensitizer on pressure resistance in deep water of emulsion explosives

NASA Astrophysics Data System (ADS)

Liu, Lei; zhang, Zhihua; Wang, Ya; Qin, hao

2018-03-01

The study on the pressure resistance performance of emulsion explosives in deep water can provide theoretical basis for underwater blasting, deep-hole blasting and emulsion explosives development. The sensitizer is an important component of emulsion explosives. By using reusable experimental devices to simulate the charge environment in deep water, the influence of the content of chemical sensitizer on the deep-water pressure resistance performance of emulsion explosives was studied. The experimental results show that with the increasing of the content of chemical sensitizer, the deep-water pressure resistance performance of emulsion explosives gradually improves, and when the pressure is fairly large, the effect is particularly pronounced; in a certain range, with the increase of the content of chemical sensitizer, that emulsion explosives’ explosion performance also gradually improve, but when the content reaches a certain value, the explosion properties declined instead; under the same emulsion matrix condition, when the content of NANO2 is 0.2%, that the emulsion explosives has good resistance to water pressure and good explosion properties. The correctness of the results above was testified in model blasting.

An integrated approach to panic prevention targeting the empirically supported risk factors of smoking and anxiety sensitivity: theoretical basis and evidence from a pilot project evaluating feasibility and short-term efficacy.

PubMed

Feldner, Matthew T; Zvolensky, Michael J; Babson, Kimberly; Leen-Feldner, Ellen W; Schmidt, Norman B

2008-10-01

Consistent with a risk reduction model of targeted prevention, the present investigation piloted and empirically evaluated the feasibility and short-term efficacy of a first-generation panic prevention program that targeted two malleable risk factors for panic development-anxiety sensitivity and daily cigarette smoking. Members of a high risk cohort, defined by high levels of anxiety sensitivity and current daily smoking (n=96), were randomly assigned to either (1) a one session intervention focused on proximally increasing motivation to quit smoking and reducing anxiety sensitivity to distally prevent the development of panic or (2) a health information control condition of comparable length. Participants were followed for 6 months. Consistent with hypotheses, those in the treatment condition showed reduced anxiety sensitivity and this effect was maintained across the follow-up period. Limited evidence also suggested the intervention increased motivation to quit smoking. We discuss how this prevention protocol can be modified in the future to enhance its effects as part of second-generation larger-scale outcome evaluations.

The Development of Cortical Sensitivity to Visual Word Forms

PubMed Central

Ben-Shachar, Michal; Dougherty, Robert F.; Deutsch, Gayle K.; Wandell, Brian A.

2011-01-01

The ability to extract visual word forms quickly and efficiently is essential for using reading as a tool for learning. We describe the first longitudinal fMRI study to chart individual changes in cortical sensitivity to written words as reading develops. We conducted four annual measurements of brain function and reading skills in a heterogeneous group of children, initially 7–12 years old. The results show age-related increase in children's cortical sensitivity to word visibility in posterior left occipito-temporal sulcus (LOTS), nearby the anatomical location of the visual word form area. Moreover, the rate of increase in LOTS word sensitivity specifically correlates with the rate of improvement in sight word efficiency, a measure of speeded overt word reading. Other cortical regions, including V1, posterior parietal cortex, and the right homologue of LOTS, did not demonstrate such developmental changes. These results provide developmental support for the hypothesis that LOTS is part of the cortical circuitry that extracts visual word forms quickly and efficiently and highlight the importance of developing cortical sensitivity to word visibility in reading acquisition. PMID:21261451

Selection on Inversion Breakpoints Favors Proximity to Pairing Sensitive Sites in Drosophila melanogaster

PubMed Central

Corbett-Detig, Russell B.

2016-01-01

Chromosomal inversions are widespread among taxa, and have been implicated in a number of biological processes including adaptation, sex chromosome evolution, and segregation distortion. Consistent with selection favoring linkage between loci, it is well established that length is a selected trait of inversions. However, the factors that affect the distribution of inversion breakpoints remain poorly understood. “Sensitive sites” have been mapped on all euchromatic chromosome arms in Drosophila melanogaster, and may be a source of natural selection on inversion breakpoint positions. Briefly, sensitive sites are genomic regions wherein proximal structural rearrangements result in large reductions in local recombination rates in heterozygotes. Here, I show that breakpoints of common inversions are significantly more likely to lie within a cytological band containing a sensitive site than are breakpoints of rare inversions. Furthermore, common inversions for which neither breakpoint intersects a sensitive site are significantly longer than rare inversions, but common inversions whose breakpoints intersect a sensitive site show no evidence for increased length. I interpret these results to mean that selection favors inversions whose breakpoints disrupt synteny near to sensitive sites, possibly because these inversions suppress recombination in large genomic regions. To my knowledge this is the first evidence consistent with positive selection acting on inversion breakpoint positions. PMID:27343234

Selection on Inversion Breakpoints Favors Proximity to Pairing Sensitive Sites in Drosophila melanogaster.

PubMed

Corbett-Detig, Russell B

2016-09-01

Chromosomal inversions are widespread among taxa, and have been implicated in a number of biological processes including adaptation, sex chromosome evolution, and segregation distortion. Consistent with selection favoring linkage between loci, it is well established that length is a selected trait of inversions. However, the factors that affect the distribution of inversion breakpoints remain poorly understood. "Sensitive sites" have been mapped on all euchromatic chromosome arms in Drosophila melanogaster, and may be a source of natural selection on inversion breakpoint positions. Briefly, sensitive sites are genomic regions wherein proximal structural rearrangements result in large reductions in local recombination rates in heterozygotes. Here, I show that breakpoints of common inversions are significantly more likely to lie within a cytological band containing a sensitive site than are breakpoints of rare inversions. Furthermore, common inversions for which neither breakpoint intersects a sensitive site are significantly longer than rare inversions, but common inversions whose breakpoints intersect a sensitive site show no evidence for increased length. I interpret these results to mean that selection favors inversions whose breakpoints disrupt synteny near to sensitive sites, possibly because these inversions suppress recombination in large genomic regions. To my knowledge this is the first evidence consistent with positive selection acting on inversion breakpoint positions. Copyright © 2016 by the Genetics Society of America.

The effect of varenicline on the development and expression of nicotine-induced behavioral sensitization and cross-sensitization in rats.

PubMed

Goutier, Wouter; Kloeze, Margreet B; McCreary, Andrew C

2015-03-01

The present study focused on the evaluation of behavioral sensitization and cross-sensitization induced by nicotine and varenicline in rats. Furthermore, it examined the influence of varenicline, a partial alpha4beta2 nicotinic receptor agonist, on nicotine-induced sensitization. To assess the development of behavioral sensitization, rats were chronically treated with vehicle, varenicline (0.03-3.0 mg/kg), nicotine (0.4 mg/kg) or combinations for 5 days and locomotor activity was measured. The expression of sensitization was assessed following a withdrawal period (17-26 days). The present results confirmed previous data showing the development and expression of nicotine-induced sensitization of locomotor activity in the rat. Varenicline did not induce sensitization on its own. When varenicline and nicotine were repeatedly administered sequentially, varenicline blocked the development and expression of nicotine-induced sensitization. Acute varenicline blocked the expression of nicotine-induced sensitization in a dose-dependent manner. Acute varenicline did not significantly increase locomotor activity, nor did it attenuate nicotine-induced sensitization. However, varenicline did cross-sensitize to the effects of nicotine, and vice versa. The present study showed that varenicline produced a dose-dependent bidirectional cross-sensitization with nicotine. Taken together, these findings provide pre-clinical evidence that varenicline is able to attenuate the effects of nicotine, yet simultaneously 'substitutes' for the effects of nicotine in the rat. Longitudinal studies would be needed to see if similar effects are seen in the clinical setting, and whether such effects contribute to the actions of varenicline as a smoking cessation aid. © 2013 Society for the Study of Addiction.

The somatostatin analogue octreotide confers sensitivity to rapamycin treatment on pituitary tumor cells.

PubMed

Cerovac, Vesna; Monteserin-Garcia, Jose; Rubinfeld, Hadara; Buchfelder, Michael; Losa, Marco; Florio, Tullio; Paez-Pereda, Marcelo; Stalla, Günter K; Theodoropoulou, Marily

2010-01-15

Rapamycin and its analogues have significant antiproliferative action against a variety of tumors. However, sensitivity to rapamycin is reduced by Akt activation that results from the ablative effects of rapamycin on a p70 S6K-induced negative feedback loop that blunts phosphoinositide 3-kinase (PI3K)-mediated support for Akt activity. Thus, sensitivity to rapamycin might be increased by imposing an upstream blockade to the PI3K/Akt pathway. Here, we investigated this model using the somatostatin analogue octreotide as a tool to decrease levels of activated Ser(473)-phosphorylated Akt (pAkt-Ser(473)) in pituitary tumor cells that express somatostatin receptors. Octreotide increased levels of phosphorylated insulin receptor substrate-1 that were suppressed by rapamycin, subsequently decreasing levels of pAkt-Ser(473) through effects on phosphotyrosine phosphatase SHP-1. Octreotide potentiated the antiproliferative effects of rapamycin in immortalized pituitary tumor cells or human nonfunctioning pituitary adenoma cells in primary cell culture, sensitizing tumor cells even to low rapamycin concentrations. Combined treatment of octreotide and rapamycin triggered G(1) cell cycle arrest, decreasing E2F transcriptional activity and cyclin E levels by increasing levels of p27/Kip1. These findings show that adjuvant treatment with a somatostatin analogue can sensitize pituitary tumor cells to the antiproliferative effects of rapamycin.

Sensitization of human carcinoma cells to alkylating agents by small interfering RNA suppression of 3-alkyladenine-DNA glycosylase.

PubMed

Paik, Johanna; Duncan, Tod; Lindahl, Tomas; Sedgwick, Barbara

2005-11-15

One of the major cytotoxic lesions generated by alkylating agents is DNA 3-alkyladenine, which can be excised by 3-alkyladenine DNA glycosylase (AAG). Inhibition of AAG may therefore result in increased cellular sensitivity to chemotherapeutic alkylating agents. To investigate this possibility, we have examined the role of AAG in protecting human tumor cells against such agents. Plasmids that express small interfering RNAs targeted to two different regions of AAG mRNA were transfected into HeLa cervical carcinoma cells and A2780-SCA ovarian carcinoma cells. Stable derivatives of both cell types with low AAG protein levels were sensitized to alkylating agents. Two HeLa cell lines with AAG protein levels reduced by at least 80% to 90% displayed a 5- to 10-fold increase in sensitivity to methyl methanesulfonate, N-methyl-N-nitrosourea, and the chemotherapeutic drugs temozolomide and 1,3-bis(2-chloroethyl)-1-nitrosourea. These cells showed no increase in sensitivity to UV light or ionizing radiation. After treatment with methyl methanesulfonate, AAG knockdown HeLa cells were delayed in S phase but accumulated in G2-M. Our data support the hypothesis that ablation of AAG activity in human tumor cells may provide a useful strategy to enhance the efficacy of current chemotherapeutic regimens that include alkylating agents.

The mycotoxin deoxynivalenol facilitates allergic sensitization to whey in mice.

PubMed

Bol-Schoenmakers, M; Braber, S; Akbari, P; de Graaff, P; van Roest, M; Kruijssen, L; Smit, J J; van Esch, B C A M; Jeurink, P V; Garssen, J; Fink-Gremmels, J; Pieters, R H H

2016-11-01

Intestinal epithelial stress or damage may contribute to allergic sensitization against certain food antigens. Hence, the present study investigated whether impairment of intestinal barrier integrity by the mycotoxin deoxynivalenol (DON) contributes to the development of whey-induced food allergy in a murine model. C3H/HeOuJ mice, orally exposed to DON plus whey once a week for 5 consecutive weeks, showed whey-specific IgG1 and IgE in serum and an acute allergic skin response upon intradermal whey challenge, although early initiating mechanisms of sensitization in the intestine appeared to be different compared with the widely used mucosal adjuvant cholera toxin (CT). Notably, DON exposure modulated tight-junction mRNA and protein levels, and caused an early increase in IL-33, whereas CT exposure affected intestinal γδ T cells. On the other hand, both DON- and CT-sensitized mice induced a time-dependent increase in the soluble IL-33 receptor ST2 (IL-1R1) in serum, and enhanced local innate lymphoid cells type 2 cell numbers. Together, these results demonstrate that DON facilitates allergic sensitization to food proteins and that development of sensitization can be induced by different molecular mechanisms and local immune responses. Our data illustrate the possible contribution of food contaminants in allergic sensitization in humans.

Temperature Sensitivity as a Microbial Trait Using Parameters from Macromolecular Rate Theory

PubMed Central

Alster, Charlotte J.; Baas, Peter; Wallenstein, Matthew D.; Johnson, Nels G.; von Fischer, Joseph C.

2016-01-01

The activity of soil microbial extracellular enzymes is strongly controlled by temperature, yet the degree to which temperature sensitivity varies by microbe and enzyme type is unclear. Such information would allow soil microbial enzymes to be incorporated in a traits-based framework to improve prediction of ecosystem response to global change. If temperature sensitivity varies for specific soil enzymes, then determining the underlying causes of variation in temperature sensitivity of these enzymes will provide fundamental insights for predicting nutrient dynamics belowground. In this study, we characterized how both microbial taxonomic variation as well as substrate type affects temperature sensitivity. We measured β-glucosidase, leucine aminopeptidase, and phosphatase activities at six temperatures: 4, 11, 25, 35, 45, and 60°C, for seven different soil microbial isolates. To calculate temperature sensitivity, we employed two models, Arrhenius, which predicts an exponential increase in reaction rate with temperature, and Macromolecular Rate Theory (MMRT), which predicts rate to peak and then decline as temperature increases. We found MMRT provided a more accurate fit and allowed for more nuanced interpretation of temperature sensitivity in all of the enzyme × isolate combinations tested. Our results revealed that both the enzyme type and soil isolate type explain variation in parameters associated with temperature sensitivity. Because we found temperature sensitivity to be an inherent and variable property of an enzyme, we argue that it can be incorporated as a microbial functional trait, but only when using the MMRT definition of temperature sensitivity. We show that the Arrhenius metrics of temperature sensitivity are overly sensitive to test conditions, with activation energy changing depending on the temperature range it was calculated within. Thus, we propose the use of the MMRT definition of temperature sensitivity for accurate interpretation of temperature sensitivity of soil microbial enzymes. PMID:27909429

Effects of early human handling on the pain sensitivity of young lambs.

PubMed

Guesgen, Mirjam J; Beausoleil, Ngaio J; Stewart, Mairi

2013-01-01

Pain sensitivity of lambs changes over the first weeks of life. However, the effects of early treatments such as human handling on pain sensitivity are unknown for this species. This study investigated the effects of regular early gentle human handling on the pain sensitivity of lambs, indicated by their behavioural responses to tail docking. Prospective part-blinded experimental study. Twenty-nine singleton Coopworth lambs (females n=14, males n=15). Starting at one day of age, lambs were either handled twice daily for 2 weeks (Handled), were kept in the presence of lambs who were being handled but were not handled themselves (Presence), or were exposed to a human only during routine feeding and care (Control). At 3 weeks of age, all lambs were tail docked using rubber rings. Changes in behaviour due to docking were calculated and change data were analyzed using two-way anova with treatment and test pen as main factors. All lambs showed significant increases in the frequency and duration of behaviours indicative of pain, including 'abnormal' behaviours, and decreases in the frequency and duration of 'normal' behaviours after docking. Handled lambs showed a smaller increase in the time spent lying abnormally after docking than did Control lambs (mean transformed change in proportion of 30 minutes spent±SE: Control 0.55±0.04; Handled 0.38±0.03; Presence 0.48±0.03; C versus H t=3.45, p=0.007). These results provide some evidence that handling early in life may reduce subsequent pain sensitivity in lambs. While the behavioural effects of handling on pain behaviour were subtle, the results suggest, at the very least, that early handling does not increase pain sensitivity in lambs and suggests there is still flexibility postnatally in the pain processing system of a precocial species. © 2012 The Authors. Veterinary Anaesthesia and Analgesia. © 2012 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.

Sensitivities of NOx transformation and the effects on surface ozone and nitrate

NASA Astrophysics Data System (ADS)

Lei, H.; Wang, J. X. L.

2014-02-01

As precursors to tropospheric ozone and nitrate, nitrogen oxide (NOx) in the present atmosphere and its transformation in response to emission and climate perturbations are studied by using the CAM-Chem model and air quality measurements from the National Emissions Inventory (NEI), Clean Air Status and Trends Network (CASTNET), and Environmental Protection Agency Air Quality System (EPA AQS). It is found that NOx transformations in present atmospheric conditions show different sensitivities over industrial and non-industrial regions. As a result, the surface ozone and nitrate formations can be divided into several regimes associated with the dominant emission types and relative levels of NOx and volatile organic compounds (VOC). Ozone production in industrial regions (the main NOx emission source areas) increases in warmer conditions and slightly decreases following an increase in NOx emissions due to NOx titration, which is opposite to the response in non-industrial regions. The ozone decrease following a temperature increase in non-industrial regions indicates that ozone production in regions that lack NOx emission sources may be sensitive to NOx transformation in remote source regions. The increase in NO2 from NOx titration over industrial regions results in an increase rate of total nitrate that remains higher than the increase rate of NOx emissions. The presented findings indicate that a change in the ozone concentration is more directly affected by changes in climate and precursor emissions, while a change in the nitrate concentration is affected by local ozone production types and their seasonal transfer. The sensitivity to temperature perturbations shows that a warmer climate accelerates the decomposition of odd nitrogen (NOy) during the night. As a result, the transformation rate of NOx to nitrate decreases. Examinations of the historical emissions and air quality records of a typical NOx-limited area, such as Atlanta and a VOC-limited area, such as Los Angeles further confirm the conclusions drawn from the modeling experiments.

Nasal bone length: prenasal thickness ratio: a strong 2D ultrasound marker for Down syndrome.

PubMed

Szabó, Andrea; Szili, Károly; Szabó, János Tamás; Sikovanyecz, János; Isaszegi, Dóra; Horváth, Emese; Szabó, János

2014-12-01

To evaluate the feasibility of incorporating two-dimensional ultrasound measurements of nasal bone length (NBL) and prenasal thickness (PT) into the second-trimester anomaly scan and to determine whether the NBL : PT ratio could help in differentiating euploid and Down syndrome fetuses. Two-dimensional measurements of NBL and PT were obtained from the midsagittal plane of the fetal head at 14-28 weeks of gestation in a Caucasian population at risk for aneuploidy. The screening performances of NBL, PT, and the ratios NBL : PT and PT : NBL were analyzed in euploid (n = 1330) and Down syndrome (n = 33) fetuses. Nasal bone length and PT alone showed strong correlations with Down syndrome (sensitivity: 76% at 1.88% and 2.35% false positive rate, respectively). However, the NBL : PT ratio showed an even stronger correlation with Down syndrome (false positive rate: 0.9%, sensitivity: 97%). The mean NBL : PT ratio showed a gradual increase from 1.48 to 1.79 (a 21.2% increase) between 14 and 28 weeks of gestation. Two-dimensional ultrasound measurements of NBL and PT, particularly the NBL : PT ratio, are highly sensitive markers for Down syndrome fetuses. © 2014 John Wiley & Sons, Ltd.

Yap5 Protein-regulated Transcription of the TYW1 Gene Protects Yeast from High Iron Toxicity*

PubMed Central

Li, Liangtao; Jia, Xuan; Ward, Diane M.; Kaplan, Jerry

2011-01-01

The budding yeast Saccharomyces cerevisiae responds to high cytosolic iron by inducing Yap5-mediated transcription. We identified genes regulated by Yap5 in response to iron and show that one of the genes induced is TYW1, which encodes an iron-sulfur cluster enzyme that participates in the synthesis of wybutosine-modified tRNA. Strains deleted for TYW1 do not show a phenotype in standard yeast medium. In contrast, overexpression of TYW1 results in decreased cell growth and induction of the iron regulon, leading to increased expression of the high affinity iron transporters. We identified a minimal domain of S. cerevisiae Tyw1 that is sufficient to induce the iron regulon. CCC1, a vacuolar iron importer, is a Yap5-regulated gene, and deletion of either CCC1 or YAP5 resulted in high iron sensitivity. Deletion of TYW1 in a Δccc1 strain led to increased iron sensitivity. The increased iron sensitivity of Δccc1Δtyw1 could be suppressed by overexpression of iron-sulfur cluster enzymes. We conclude that the Yap5-mediated induction of TYW1 provides protection from high iron toxicity by the consumption of free cytosolic iron through the formation of protein-bound iron-sulfur clusters. PMID:21917924

An evidence-based framework for predicting the impact of differing autotroph-heterotroph thermal sensitivities on consumer–prey dynamics

PubMed Central

Yang, Zhou; Zhang, Lu; Zhu, Xuexia; Wang, Jun; Montagnes, David J S

2016-01-01

Increased temperature accelerates vital rates, influencing microbial population and wider ecosystem dynamics, for example, the predicted increases in cyanobacterial blooms associated with global warming. However, heterotrophic and mixotrophic protists, which are dominant grazers of microalgae, may be more thermally sensitive than autotrophs, and thus prey could be suppressed as temperature rises. Theoretical and meta-analyses have begun to address this issue, but an appropriate framework linking experimental data with theory is lacking. Using ecophysiological data to develop a novel model structure, we provide the first validation of this thermal sensitivity hypothesis: increased temperature improves the consumer's ability to control the autotrophic prey. Specifically, the model accounts for temperature effects on auto- and mixotrophs and ingestion, growth and mortality rates, using an ecologically and economically important system (cyanobacteria grazed by a mixotrophic flagellate). Once established, we show the model to be a good predictor of temperature impacts on consumer–prey dynamics by comparing simulations with microcosm observations. Then, through simulations, we indicate our conclusions remain valid, even with large changes in bottom-up factors (prey growth and carrying capacity). In conclusion, we show that rising temperature could, counterintuitively, reduce the propensity for microalgal blooms to occur and, critically, provide a novel model framework for needed, continued assessment. PMID:26684731

Trilayer TMDC Heterostructures for MOSFETs and Nanobiosensors

NASA Astrophysics Data System (ADS)

Datta, Kanak; Shadman, Abir; Rahman, Ehsanur; Khosru, Quazi D. M.

2017-02-01

Two dimensional materials such as transition metal dichalcogenides (TMDC) and their bi-layer/tri-layer heterostructures have become the focus of intense research and investigation in recent years due to their promising applications in electronics and optoelectronics. In this work, we have explored device level performance of trilayer TMDC heterostructure (MoS2/MX2/MoS2; M = Mo or, W and X = S or, Se) metal oxide semiconductor field effect transistors (MOSFETs) in the quantum ballistic regime. Our simulation shows that device `on' current can be improved by inserting a WS2 monolayer between two MoS2 monolayers. Application of biaxial tensile strain reveals a reduction in drain current which can be attributed to the lowering of carrier effective mass with increased tensile strain. In addition, it is found that gate underlap geometry improves electrostatic device performance by improving sub-threshold swing. However, increase in channel resistance reduces drain current. Besides exploring the prospect of these materials in device performance, novel trilayer TMDC heterostructure double gate field effect transistors (FETs) are proposed for sensing Nano biomolecules as well as for pH sensing. Bottom gate operation ensures these FETs operating beyond Nernst limit of 59 mV/pH. Simulation results found in this work reveal that scaling of bottom gate oxide results in better sensitivity while top oxide scaling exhibits an opposite trend. It is also found that, for identical operating conditions, proposed TMDC FET pH sensors show super-Nernst sensitivity indicating these materials as potential candidates in implementing such sensor. Besides pH sensing, all these materials show high sensitivity in the sub-threshold region as a channel material in nanobiosensor while MoS2/WS2/MoS2 FET shows the least sensitivity among them.

Eating high fat chow increases the sensitivity of rats to quinpirole-induced discriminative stimulus effects and yawning

PubMed Central

Baladi, Michelle G; France, Charles P

2010-01-01

Discriminative stimulus effects of directly-acting dopamine receptor agonists (e.g. quinpirole) appear to be mediated by D3 receptors in free-feeding rats. Free access to high fat chow increases sensitivity to quinpirole-induced yawning and the current study examined whether eating high fat chow increases sensitivity to the discriminative stimulus effects of quinpirole. Five rats discriminated between 0.032 mg/kg quinpirole and vehicle while responding under a continuous reinforcement schedule of stimulus shock termination. When rats had free access to high fat chow (discrimination training was suspended), the quinpirole discrimination dose-response curve shifted leftward, possibly indicating enhanced sensitivity at D3 receptors. In the same rats, both the ascending (mediated by D3 receptors) and descending (mediated by D2 receptors) limbs of the dose- response curve for quinpirole-induced yawning shifted leftward. When rats had free access to a standard chow (discrimination training was suspended), the quinpirole discrimination and yawning dose-response curves did not change. Together with published data showing that the discriminative stimulus effects of quinpirole in free- feeding rats are mediated by D3 receptors and the insensitivity of this effect of quinpirole to food restriction (shown to increase sensitivity to D2 but not D3-mediated effects), these results suggest that the leftward shift of the discrimination dose-response curve when rats eat high fat chow is likely due to enhanced sensitivity at D3 receptors. Thus, eating high fat food enhances drug effects in a manner that might impact clinical effects of drugs or vulnerability to drug abuse. PMID:20729718

Eating high-fat chow increases the sensitivity of rats to quinpirole-induced discriminative stimulus effects and yawning.

PubMed

Baladi, Michelle G; France, Charles P

2010-10-01

Discriminative stimulus effects of direct acting dopamine receptor agonists (e.g. quinpirole) appear to be mediated by D3 receptors in free-feeding rats. Free access to high-fat chow increases sensitivity to quinpirole-induced yawning, and this study examined whether eating high-fat chow increases sensitivity to the discriminative stimulus effects of quinpirole. Five rats discriminated between 0.032 mg/kg quinpirole and vehicle while responding under a continuous reinforcement schedule of stimulus shock termination. When rats had free access to high-fat chow (discrimination training was suspended), the quinpirole discrimination dose-response curve shifted leftward, possibly indicating enhanced sensitivity at D3 receptors. In the same rats, both the ascending (mediated by D3 receptors) and descending (mediated by D2 receptors) limbs of the dose-response curve for quinpirole-induced yawning shifted leftward. When rats had free access to a standard chow (discrimination training was suspended), the quinpirole discrimination and yawning dose-response curves did not change. Together with published data showing that the discriminative stimulus effects of quinpirole in free-feeding rats are mediated by D3 receptors and the insensitivity of this effect of quinpirole to food restriction (shown to increase sensitivity to D2 but not D3-mediated effects), these results suggest that the leftward shift of the discrimination dose-response curve when rats eat high-fat chow is likely because of enhanced sensitivity at D3 receptors. Thus, eating high-fat food enhances drug effects in a manner that might impact clinical effects of drugs or vulnerability to drug abuse.

MHC-I modulation due to changes in tumor cell metabolism regulates tumor sensitivity to CTL and NK cells

PubMed Central

Catalán, Elena; Charni, Seyma; Jaime, Paula; Aguiló, Juan Ignacio; Enríquez, José Antonio; Naval, Javier; Pardo, Julián; Villalba, Martín; Anel, Alberto

2015-01-01

Tumor cells have a tendency to use glucose fermentation to obtain energy instead of mitochondrial oxidative phosphorylation (OXPHOS). We demonstrated that this phenotype correlated with loss of ERK5 expression and with reduced MHC class I expression. Consequently, tumor cells could evade cytotoxic T lymphocyte (CTL)-mediated immune surveillance, but also increase their sensitivity to natural killer (NK) cells. These outcomes were evaluated using two cellular models: leukemic EL4 cells and L929 transformed fibroblasts and their derived ρ° cell lines, which lack mitochondrial DNA. We have also used a L929 cell sub-line that spontaneously lost matrix attachment (L929dt), reminiscent of metastasis generation, that also downregulated MHC-I and ERK5 expression. MHC-I expression is lower in ρ° cells than in the parental cell lines, but they were equally sensitive to CTL. On the contrary, ρ° cells were more sensitive to activated NK cells than parental cells. On the other hand, L929dt cells were resistant to CTL and NK cells, showed reduced viability when forced to perform OXPHOS, and surviving cells increased MHC-I expression and became sensitive to CTL. The present results suggest that when the reduction in MHC-I levels in tumor cells due to glycolytic metabolism is partial, the increase in sensitivity to NK cells seems to predominate. However, when tumor cells completely lose MHC-I expression, the combination of treatments that increase OXPHOS with CTL-mediated immunotherapy could be a promising therapeutic approach. PMID:25949869

MHC-I modulation due to changes in tumor cell metabolism regulates tumor sensitivity to CTL and NK cells.

PubMed

Catalán, Elena; Charni, Seyma; Jaime, Paula; Aguiló, Juan Ignacio; Enríquez, José Antonio; Naval, Javier; Pardo, Julián; Villalba, Martín; Anel, Alberto

2015-01-01

Tumor cells have a tendency to use glucose fermentation to obtain energy instead of mitochondrial oxidative phosphorylation (OXPHOS). We demonstrated that this phenotype correlated with loss of ERK5 expression and with reduced MHC class I expression. Consequently, tumor cells could evade cytotoxic T lymphocyte (CTL)-mediated immune surveillance, but also increase their sensitivity to natural killer (NK) cells. These outcomes were evaluated using two cellular models: leukemic EL4 cells and L929 transformed fibroblasts and their derived ρ° cell lines, which lack mitochondrial DNA. We have also used a L929 cell sub-line that spontaneously lost matrix attachment (L929dt), reminiscent of metastasis generation, that also downregulated MHC-I and ERK5 expression. MHC-I expression is lower in ρ° cells than in the parental cell lines, but they were equally sensitive to CTL. On the contrary, ρ° cells were more sensitive to activated NK cells than parental cells. On the other hand, L929dt cells were resistant to CTL and NK cells, showed reduced viability when forced to perform OXPHOS, and surviving cells increased MHC-I expression and became sensitive to CTL. The present results suggest that when the reduction in MHC-I levels in tumor cells due to glycolytic metabolism is partial, the increase in sensitivity to NK cells seems to predominate. However, when tumor cells completely lose MHC-I expression, the combination of treatments that increase OXPHOS with CTL-mediated immunotherapy could be a promising therapeutic approach.

Multiple P2Y receptor subtypes in the apical membranes of polarized epithelial cells

PubMed Central

McAlroy, H L; Ahmed, S; Day, S M; Baines, D L; Wong, H Y; Yip, C Y; Ko, W H; Wilson, S M; Collett, A

2000-01-01

Apical ATP, ATP, UTP and UDP evoked transient increases in short circuit current (ISC, a direct measure of transepithelial ion transport) in confluent Caco-2 cells grown on permeable supports. These responses were mediated by a population of at least three pharmacologically distinct receptors. Experiments using cells grown on glass coverslips showed that ATP and UTP consistently increased intracellular free calcium ([Ca2+]i) whilst sensitivity to UDP was variable. Cross desensitization experiments suggested that the responses to UTP and ATP were mediated by a common receptor population. Messenger RNA transcripts corresponding to the P2Y2, P2Y4 and P2Y6 receptors genes were detected in cells grown on Transwell membranes by the reverse transcriptase–polymerase chain reaction. Identical results were obtained for cells grown on glass. Experiments in which ISC and [Ca2+]i were monitored simultaneously in cells on Transwell membranes, confirmed that apical ATP and UTP increased both parameters and showed that the UDP-evoked increase in ISC was accompanied by a [Ca2+]i-signal. Ionomycin consistently increased [Ca2+]i in such polarized cells but caused no discernible change in ISC. However, subsequent application of apical ATP or UTP evoked a small rise in ISC but no rise in [Ca2+]i. UDP evoked no such response. As well as evoking increases in [Ca2+]i, the ATP/UTP-sensitive receptors present in Caco-2 cells thus allow direct control over ion channels in the apical membrane. The UDP-sensitive receptors, however, appear to simply evoke a rise in [Ca2+]i. PMID:11139443

Voltage-sensitive rhodol with enhanced two-photon brightness.

PubMed

Kulkarni, Rishikesh U; Kramer, Daniel J; Pourmandi, Narges; Karbasi, Kaveh; Bateup, Helen S; Miller, Evan W

2017-03-14

We have designed, synthesized, and applied a rhodol-based chromophore to a molecular wire-based platform for voltage sensing to achieve fast, sensitive, and bright voltage sensing using two-photon (2P) illumination. Rhodol VoltageFluor-5 (RVF5) is a voltage-sensitive dye with improved 2P cross-section for use in thick tissue or brain samples. RVF5 features a dichlororhodol core with pyrrolidyl substitution at the nitrogen center. In mammalian cells under one-photon (1P) illumination, RVF5 demonstrates high voltage sensitivity (28% ΔF/F per 100 mV) and improved photostability relative to first-generation voltage sensors. This photostability enables multisite optical recordings from neurons lacking tuberous sclerosis complex 1, Tsc1, in a mouse model of genetic epilepsy. Using RVF5, we show that Tsc1 KO neurons exhibit increased activity relative to wild-type neurons and additionally show that the proportion of active neurons in the network increases with the loss of Tsc1. The high photostability and voltage sensitivity of RVF5 is recapitulated under 2P illumination. Finally, the ability to chemically tune the 2P absorption profile through the use of rhodol scaffolds affords the unique opportunity to image neuronal voltage changes in acutely prepared mouse brain slices using 2P illumination. Stimulation of the mouse hippocampus evoked spiking activity that was readily discerned with bath-applied RVF5, demonstrating the utility of RVF5 and molecular wire-based voltage sensors with 2P-optimized fluorophores for imaging voltage in intact brain tissue.

Relative Sensitivity of Photosynthesis and Respiration to Freeze-Thaw Stress in Herbaceous Species 1

PubMed Central

Steffen, Kenneth L.; Arora, Rajeev; Palta, Jiwan P.

1989-01-01

The relative effect of a freeze-thaw cycle on photosynthesis, respiration, and ion leakage of potato leaf tissue was examined in two potato species, Solanum acaule Bitt. and Solanum commersonii Dun. Photosynthesis was found to be much more sensitive to freezing stress than was respiration, and demonstrated more than a 60% inhibition before any impairment of respiratory function was observed. Photosynthesis showed a slight to moderate inhibition when only 5 to 10% of the total electrolytes had leaked from the tissue (reversible injury). This was in contrast to respiration which showed no impairment until temperatures at which about 50% ion leakage (irreversible injury) had occurred. The influence of freeze-thaw protocol was further examined in S. acaule and S. commersonii, in order to explore discrepancies in the literature as to the relative sensitivities of photosynthesis and respiration. As bath cooling rates increased from 1°C/hour to about 3 or 6°C/hour, there was a dramatic increase in the level of damage to all measured cellular functions. The initiation of ice formation in deeply supercooled tissue caused even greater damage. As the cooling rates used in stress treatments increased, the differential sensitivity between photosynthesis and respiration nearly disappeared. Examination of agriculturally relevant, climatological data from an 11 year period confirmed that air cooling rates in the freezing range do not exceed 2°C/hour. It was demonstrated, in the studies presented here, that simply increasing the actual cooling rate from 1.0 to 2.9°C/hour, in frozen tissue from paired leaflet halves, meant the difference between cell survival and cell death. Images Figure 4 Figure 5 PMID:16666712

Epithelial-mesenchymal transition leads to crizotinib resistance in H2228 lung cancer cells with EML4-ALK translocation.

PubMed

Kim, Hyeong Ryul; Kim, Woo Sung; Choi, Yun Jung; Choi, Chang Min; Rho, Jin Kyung; Lee, Jae Cheol

2013-12-01

Epithelial-mesenchymal transition (EMT) is associated with reduced sensitivity to many chemotherapeutic drugs, including EGFR tyrosine kinase inhibitors. Here, we investigated if this reduced sensitivity also contributes to resistance to crizotinib, an ALK inhibitor of lung cancer that exhibits the EML4-ALK translocation. We established a crizotinib-resistant subline (H2228/CR), which was derived from the parental H2228 cell line by long-term exposure to increasing concentrations of crizotinib. Characteristics associated with EMT, including morphology, EMT marker proteins, and cellular mobility, were analyzed. Compared with H2228 cells, the growth of H2228/CR cells was independent of EML4-ALK, and H2228/CR cells showed cross-resistance to TAE-684 (a second-generation ALK inhibitor). Phenotypic changes to the spindle-cell shape were noted in H2228/CR cells, which were accompanied by a decrease in E-cadherin and increase in vimentin and AXL. In addition, H2228/CR cells showed increased secretion and expression of TGF-β1. Invasion and migration capabilities were dramatically increased in H2228/CR cells. Applying TGF-β1 treatment to parental H2228 cells for 72 h induced reversible EMT, leading to crizotinib resistance, but this was reversed by the removal of TGF-β1. Suppression of vimentin in H2228/CR cells by siRNA treatment restored sensitivity to crizotinib. Furthermore, these resistant cells remained highly sensitive to the Hsp90 inhibitors, similar to the parental H2228 cells. In conclusion, we suggest EMT is possibly involved in acquired resistance to crizotinib, and that HSP90 inhibitors could be a promising option for the treatment of EMT. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Nicotine-induced locomotor sensitization: pharmacological analyses with candidate smoking cessation aids.

PubMed

Goutier, Wouter; Kloeze, Margreet; McCreary, Andrew C

2016-03-01

There are a number of approved therapeutics for the management of alcohol dependence, which might also convey the potential as smoking cessation aids. The present study investigated the effect of a few of these therapeutics and potential candidates (non-peptide vasopressin V1b antagonists) on the expression of nicotine-induced behavioral sensitization in Wistar rats. The following compounds were included in this evaluation: rimonabant, bupropion, topiramate, acamprosate, naltrexone, mecamylamine, nelivaptan (SSR-149415, V1b antagonist) and two novel V1b antagonists. Following the development of nicotine-induced locomotor sensitization and a withdrawal period, the expression of sensitization was assessed in the presence of one of the examined agents given 30 minutes prior to the nicotine challenge injection. Acamprosate, naltrexone, rimonabant, mecamylamine, nelivaptan and V1b antagonist 'compound 2' significantly antagonized the expression of nicotine-induced sensitization. Whereas topiramate showed a trend for effects, the V1b antagonist 'compound 1' did not show any significant effects. Bupropion failed to block sensitization but increased activity alone and was therefore tested in development and cross-sensitization studies. Taken together, these findings provide pre-clinical evidence that these molecules attenuated the expression of nicotine-induced sensitization and should be further investigated as putative treatments for nicotine addiction. Moreover, V1b antagonists should be further investigated as a potential novel smoking cessation aid. © 2014 Society for the Study of Addiction.

Prenatal Stress as a Risk-and an Opportunity-Factor.

PubMed

Hartman, Sarah; Freeman, Sara M; Bales, Karen L; Belsky, Jay

2018-04-01

Two separate lines of research indicate (a) that prenatal stress is associated with heightened behavioral and physiological reactivity and (b) that these postnatal phenotypes are associated with increased susceptibility to both positive and negative developmental experiences. Therefore, prenatal stress may increase sensitivity to the rearing environment. We tested this hypothesis by manipulating prenatal stress and rearing-environment quality, using a cross-fostering paradigm, in prairie voles. Results showed that prenatally stressed voles, as adults, displayed the highest behavioral and physiological reactivity when cross-fostered to low-contact (i.e., low-quality) rearing but the lowest behavioral and physiological reactivity when cross-fostered to high-contact (i.e., high-quality) rearing; non-prenatally stressed voles showed no effect of rearing condition. Additionally, while neither prenatal stress nor rearing condition affected oxytocin receptor binding, prenatally stressed voles cross-fostered to high-contact rearing showed the highest vasopressin-1a receptor binding in the amygdala. Results indicate that prenatal stress induces greater environmental sensitivity, making it both a risk and an opportunity factor.

Heterozygous Inverdale ewes show increased ovulation rate sensitivity to pre-mating nutrition.

PubMed

Demmers, K J; Smaill, B; Davis, G H; Dodds, K G; Juengel, J L

2011-01-01

This study aimed to determine whether ewes heterozygous (I+) for the Inverdale mutation of the bone morphogenetic protein-15 (BMP15) gene with high natural ovulation rate (OR) show similar sensitivity to nutritional manipulation as non-carriers (++). Increasing pre-mating nutrition results in OR increases in sheep, but whether this effect occurs in ewes with naturally high OR is unknown. Over 2 years, I+ or ++ ewes were given high (ad libitum) or control (maintenance) pasture allowances for 6 weeks prior to mating at a synchronised oestrus, with OR measured 8 days later. The high group increased in weight compared with controls (+5.84kg; P<0.01), accompanied by increased OR (+19%; P<0.01). As well as having higher OR (+45%; P<0.01), I+ ewes responded to increased feed with a larger proportional increase in OR (+27%; P<0.01) compared with the response in ++ ewes (+11%; P<0.05), suggesting an interaction between BMP15 levels and nutritional signals in the follicle to control OR. Although litter size increases only tended to significance (+12%; P=0.06), extra feed resulted in over 50% of I+ ewes giving birth to more than three lambs, compared with 20-31% of I+ ewes on maintenance rations. This information can guide feed management of prolific Inverdale ewes prior to breeding.

Fluorescent sensing with Fresnel microlenses for optofluidic systems

NASA Astrophysics Data System (ADS)

Siudzińska, Anna; Miszczuk, Andrzej; Marczak, Jacek; Komorowska, Katarzyna

2017-05-01

The concept of fluorescent sensing in a microchannel equipped with focusing light Fresnel lenses has been demonstrated. The concept employs a line or array of Fresnel lenses generating a line or array of focused light spots within a microfluidic channel, to increase the sensitivity of fluorescent signal detection in the system. We have presented efficient methods of master mold fabrication based on the lithography method and focused ion beam milling. The flexible microchannel was fabricated by an imprint process with new thiolene-epoxy resin with a good ability to replicate even submicron-size features. For final imprinted lenses, the measured background to peak signal level shows more than nine times the increase in brightness at the center of the focal spot for the green part of the spectrum (532 nm). The effectiveness of the microlenses in fluorescent-marked Escherichia coli bacteria was confirmed in a basic fluoroscope experiment, showing the increase of the sensitivity of the detection by the order of magnitude.

Synthesis and Swelling Behavior of pH-Sensitive Semi-IPN Superabsorbent Hydrogels Based on Poly(acrylic acid) Reinforced with Cellulose Nanocrystals

PubMed Central

Lim, Lim Sze; Rosli, Noor Afizah; Ahmad, Ishak; Mat Lazim, Azwan; Mohd Amin, Mohd Cairul Iqbal

2017-01-01

pH-sensitive poly(acrylic acid) (PAA) hydrogel reinforced with cellulose nanocrystals (CNC) was prepared. Acrylic acid (AA) was subjected to chemical cross-linking using the cross-linking agent MBA (N,N-methylenebisacrylamide) with CNC entrapped in the PAA matrix. The quantity of CNC was varied between 0, 5, 10, 15, 20, and 25 wt %. X-ray diffraction (XRD) data showed an increase in crystallinity with the addition of CNC, while rheology tests demonstrated a significant increase in the storage modulus of the hydrogel with an increase in CNC content. It was found that the hydrogel reached maximum swelling at pH 7. The potential of the resulting hydrogels to act as drug carriers was then evaluated by means of the drug encapsulation efficiency test using theophylline as a model drug. It was observed that 15% CNC/PAA hydrogel showed the potential to be used as drug carrier system. PMID:29156613

Relationship between Trends in Land Precipitation and Tropical SST Gradient

NASA Technical Reports Server (NTRS)

Chung, Chul Eddy; Ramanathan, V.

2007-01-01

In this study, we examined global zonal/annual mean precipitation trends. Land precipitation trend from 1951 to 2002 shows widespread drying between 10 S to 20 N but the trend from 1977 to 2002 shows partial recovery. Based on general circulation model sensitivity studies, we suggested that these features are driven largely by the meridional SST gradient trend in the tropics. Our idealized CCM3 experiments substantiated that land precipitation is more sensitive to meridional SST gradient than to an overall tropical warming. Various simulations produced for the IPCC 4th assessment report demonstrate that increasing CO2 increases SST in the entire tropics non-uniformly and increases land precipitation only in certain latitude belts, again pointing to the importance of SST gradient change. Temporally varying aerosols in the IPCC simulations alter meridional SST gradient and land precipitation substantially. Anthropogenic aerosol direct solar forcing without its effects on SST is shown by the CCM3 to have weak but non-negligible influence on land precipitation.

Enhanced Photovoltaic Performances of Dye-Sensitized Solar Cells by Co-Sensitization of Benzothiadiazole and Squaraine-Based Dyes.

PubMed

Islam, Ashraful; Akhtaruzzaman, Md; Chowdhury, Towhid H; Qin, Chuanjiang; Han, Liyuan; Bedja, Idriss M; Stalder, Romain; Schanze, Kirk S; Reynolds, John R

2016-02-01

Dye-sensitized solar cells (DSSCs) based on a donor-acceptor-donor oligothienylene dye containing benzothiadiazole (T4BTD-A) were cosensitized with dyes containing cis-configured squaraine rings (HSQ3 and HSQ4). The cosensitized dyes showed incident monochromatic photon-to-current conversion efficiency (IPCE) greater than 70% in the 300-850 nm wavelength region. The individual overall conversion efficiencies of the sensitizers T4BTD-A, HSQ3, and HSQ4 were 6.4%, 4.8%, and 5.8%, respectively. Improved power conversion efficiencies of 7.0% and 7.7% were observed when T4BTD-A was cosensitized with HSQ3 and HSQ4, respectively, thanks to a significant increase in current density (JSC) for the cosensitized DSSCs. Intensity-modulated photovoltage spectroscopy results showed a longer lifetime for cosensitized T4BTD-A+HSQ3 and T4BTD-A+HSQ4 compared to that of HSQ3 and HSQ4, respectively.

Application of positron annihilation lineshape analysis to fatigue damage and thermal embrittlement for nuclear plant materials

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

Uchida, M.; Ohta, Y.; Nakamura, N.

1995-08-01

Positron annihilation (PA) lineshape analysis is sensitive to detect microstructural defects such as vacancies and dislocations. The authors are developing a portable system and applying this technique to nuclear power plant material evaluations; fatigue damage in type 316 stainless steel and SA508 low alloy steel, and thermal embrittlement in duplex stainless steel. The PA technique was found to be sensitive in the early fatigue life (up to 10%), but showed a little sensitivity for later stages of the fatigue life in both type 316 stainless steel and SA508 ferritic steel. Type 316 steel showed a higher PA sensitivity than SA508more » since the initial SA508 microstructure already contained a high dislocation density in the as-received state. The PA parameter increased as a fraction of aging time in CF8M samples aged at 350 C and 400 C, but didn`t change much in CF8 samples.« less

Decrease of Plasma Glucose by Hibiscus taiwanensis in Type-1-Like Diabetic Rats

PubMed Central

Wang, Lin-Yu; Chung, Hsien-Hui

2013-01-01

Hibiscus taiwanensis (Malvaceae) is widely used as an alternative herb to treat disorders in Taiwan. In the present study, it is used to screen the effect on diabetic hyperglycemia in streptozotocin-induced diabetic rats (STZ-diabetic rats). The extract of Hibiscus taiwanensis showed a significant plasma glucose-lowering action in STZ-diabetic rats. Stems of Hibiscus taiwanensis are more effective than other parts to decrease the plasma glucose in a dose-dependent manner. Oral administration of Hibiscus taiwanensis three times daily for 3 days into STZ-diabetic rats increased the sensitivity to exogenous insulin showing an increase in insulin sensitivity. Moreover, similar repeated administration of Hibiscus taiwanensis for 3 days in STZ-diabetic rats produced a marked reduction of phosphoenolpyruvate carboxykinase (PEPCK) expression in liver and an increased expression of glucose transporter subtype 4 (GLUT 4) in skeletal muscle. Taken together, our results suggest that Hibiscus taiwanensis has the ability to lower plasma glucose through an increase in glucose utilization via elevation of skeletal GLUT 4 and decrease of hepatic PEPCK in STZ-diabetic rats. PMID:23690841

Broadband sensitized photon up-conversion at subsolar irradiance (Conference Presentation)

NASA Astrophysics Data System (ADS)

Pedrini, Jacopo; Monguzzi, Angelo; Meinardi, Francesco

2016-09-01

A crucial limit of solar devices is their inability to harvest the full solar spectrum. Currently, sensitized up-conversion based on triplet-tripled annihilation (STTA-UC) in bi-component organic systems is the most promising technique to recover sub-bandgap photons, showing good efficiencies also at excitation intensities comparable to the solar irradiance. In STTA-UC, high-energy light is generated through annihilation of metastable triplet states of molecules acting as emitters, which are populated via resonant energy transfer from a light-harvesting sensitizer. However, suitable sensitizers show narrow absorption bands, limiting the fraction of recoverable photons, therefore preventing the application of STTA-UC to real-world devices. Here we demonstrate how to overcome the described limit by using multiple sensitizers that work cooperatively to broaden the overall system absorption band. This is obtained using an additional sensitizer that transfers the extra harvested energy to the main one (sensitization of the sensitizer), or a set of properly designed complementary absorbing sensitizers all able to excite simultaneously the same emitter (multi-sensitizers). In both cases STTA-UC performances result strongly enhanced compared to the corresponding mono-sensitizer system, increasing the up-converted light intensity generated at AM 1.5 up to two times. Remarkably, by coupling our light converters to a DSSC we prove its operation by exploiting exclusively sub-bandgap photons. A detailed modeling of the photophysical processes involved in these complex systems allows us to draw the guidelines for the design of the next generation STTA-UC materials, encouraging their application to photovoltaic technologies.

High fat diet and food restriction differentially modify the behavioral effects of quinpirole and raclopride in rats.

PubMed

Baladi, Michelle G; France, Charles P

2009-05-21

Nutritional status can impact dopamine systems in a manner that might be important to understanding possible common neurobiological mechanisms that mediate abnormal compulsive food (e.g., obesity) and drug taking. Limiting food intake, for example, can increase sensitivity to the behavioral effects of indirect-acting dopamine receptor agonists. Much less is known regarding possible diet-induced changes in sensitivity to direct-acting dopamine receptor drugs. The present study investigated the effects of a high fat diet and of food restriction on sensitivity of rats to the behavioral effects of a direct-acting dopamine receptor agonist and a dopamine receptor antagonist. Free access to high fat chow increased sensitivity to quinpirole-induced yawning without changing sensitivity to raclopride-induced catalepsy or quinpirole-induced hypothermia. Food restriction (10 g/day) decreased sensitivity to quinpirole-induced yawning and raclopride-induced catalepsy without affecting sensitivity to quinpirole-induced hypothermia. Free access to a standard chow restored sensitivity to the behavioral effects of both drugs in rats that were previously food-restricted but not in rats that previously ate a high fat diet. These data confirm that food restriction can decrease sensitivity to behavioral effects of direct-acting dopamine receptor drugs, they provide evidence (i.e., no change in hypothermic effects) indicating that these changes are not due to pharmacokinetic mechanisms, and they provide initial evidence showing enhanced sensitivity to behavioral effects of dopamine receptor drugs in rats eating a high fat diet. These changes in sensitivity of dopamine systems could be relevant to understanding the impact of nutrition on therapeutic and recreational drug use.

High fat diet and food restriction differentially modify the behavioral effects of quinpirole and raclopride in rats

PubMed Central

Baladi, Michelle G; France, Charles P

2009-01-01

Nutritional status can impact dopamine systems in a manner that might be important to understanding possible common neurobiological mechanisms that mediate abnormal compulsive food (e.g., obesity) and drug taking. Limiting food intake, for example, can increase sensitivity to the behavioral effects of indirect-acting dopamine receptor agonists. Much less is known regarding possible diet-induced changes in sensitivity to direct-acting dopamine receptor drugs. The present study investigated the effects of a high fat diet and of food restriction on sensitivity of rats to the behavioral effects of a direct-acting dopamine receptor agonist and a dopamine receptor antagonist. Free access to high fat chow increased sensitivity to quinpirole-induced yawning without changing sensitivity to raclopride-induced catalepsy or quinpirole-induced hypothermia. Food restriction (10 g/day) decreased sensitivity to quinpirole-induced yawning and raclopride-induced catalepsy without affecting sensitivity to quinpirole-induced hypothermia. Free access to a standard chow restored sensitivity to the behavioral effects of both drugs in rats that were previously food-restricted but not in rats that previously ate a high fat diet. These data confirm that food restriction can decrease sensitivity to behavioral effects of direct-acting dopamine receptor drugs, they provide evidence (i.e., no change in hypothermic effects) indicating that these changes are not due to pharmacokinetic mechanisms, and they provide initial evidence showing enhanced sensitivity to behavioral effects of dopamine receptor drugs in rats eating a high fat diet. These changes in sensitivity of dopamine systems could be relevant to understanding the impact of nutrition on therapeutic and recreational drug use. PMID:19327348

Understanding Socio-Hydrology System in the Kissimmee River Basin

NASA Astrophysics Data System (ADS)

Chen, X.; Wang, D.; Tian, F.; Sivapalan, M.

2014-12-01

This study is to develop a conceptual socio-hydrology model for the Kissimmee River Basin. The Kissimmee River located in Florida was channelized in mid-20 century for flood protection. However, the environmental issues caused by channelization led Floridians to conduct a restoration project recently, focusing on wetland recovery. As a complex coupled human-water system, Kissimmee River Basin shows the typical socio-hydrology interactions. Hypothetically, the major reason to drive the system from channelization to restoration is that the community sensitivity towards the environment has changed from controlling to restoring. The model developed in this study includes 5 components: water balance, flood risk, wetland area, crop land area, and community sensitivity. Furthermore, urban population and rural population in the basin have different community sensitivities towards the hydrologic system. The urban population, who live further away from the river are more sensitive to wetland restoration; while the rural population, who live closer to the river are more sensitive to flood protection. The power dynamics between the two groups and its impact on management decision making is described in the model. The model is calibrated based on the observed watershed outflow, wetland area and crop land area. The results show that the overall focus of community sensitivity has changed from flood protection to wetland restoration in the past 60 years in Kissimmee River Basin, which confirms the study hypothesis. There are two main reasons for the community sensitivity change. Firstly, people's flood memory is fading because of the effective flood protection, while the continuously shrinking wetland and the decreasing bird and fish population draw more and more attention. Secondly, in the last 60 years, the urban population in Florida drastically increased compared with a much slower increase of rural population. As a result, the community sensitivity of urban population towards wetland restoration has more weight than the rural population's towards flood protection.

A Study on Structural, Corrosion, and Sensitization Behavior of Ultrafine and Coarse Grain 316 Stainless Steel Processed by Multiaxial Forging and Heat Treatment

NASA Astrophysics Data System (ADS)

Kiahosseini, Seyed Rahim; Mohammadi Baygi, Seyyed Javad; Khalaj, Gholamreza; Khoshakhlagh, Ali; Samadipour, Razieh

2018-01-01

Cubic specimens from AISI 316 stainless steel were multiaxially forged to 15 passes and annealed at 1200 °C for 1, 2, and 3 h and finally sensitized at 700 °C for 24 h. Examination of samples indicated that the hardness of the annealed samples was reduced from 153 to 110, 81, and 74 HV for as-received sample and under 1, 2, and 3 h of annealing, and increased from 245 to 288 HV for samples forged at 3 and 7 passes. However, no significant changes were observed in a large number of passes and at about 300 HV. Degree of sensitization of samples was increased to approximately 27.3% at 3-h annealing but reduced to 1.23% by 15 passes of MF. The potentiodynamic polarization test shows that the breakdown potentials decreased with annealing time from 0.6 to - 102 (mV/SCE) for as-received and 3-h annealed specimen. These potentials increased to approximately - 16.5 mV with the increase in MF passes to 15. These observations indicated that the chromium carbide deposition affects Cr-depleted zone, which can subsequently affect the degree of sensitization and pitting corrosion resistance of AISI 316 austenitic stainless steel.

Adaptive smoothing based on Gaussian processes regression increases the sensitivity and specificity of fMRI data.

PubMed

Strappini, Francesca; Gilboa, Elad; Pitzalis, Sabrina; Kay, Kendrick; McAvoy, Mark; Nehorai, Arye; Snyder, Abraham Z

2017-03-01

Temporal and spatial filtering of fMRI data is often used to improve statistical power. However, conventional methods, such as smoothing with fixed-width Gaussian filters, remove fine-scale structure in the data, necessitating a tradeoff between sensitivity and specificity. Specifically, smoothing may increase sensitivity (reduce noise and increase statistical power) but at the cost loss of specificity in that fine-scale structure in neural activity patterns is lost. Here, we propose an alternative smoothing method based on Gaussian processes (GP) regression for single subjects fMRI experiments. This method adapts the level of smoothing on a voxel by voxel basis according to the characteristics of the local neural activity patterns. GP-based fMRI analysis has been heretofore impractical owing to computational demands. Here, we demonstrate a new implementation of GP that makes it possible to handle the massive data dimensionality of the typical fMRI experiment. We demonstrate how GP can be used as a drop-in replacement to conventional preprocessing steps for temporal and spatial smoothing in a standard fMRI pipeline. We present simulated and experimental results that show the increased sensitivity and specificity compared to conventional smoothing strategies. Hum Brain Mapp 38:1438-1459, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

A winged helix forkhead (FOXD2) tunes sensitivity to cAMP in T lymphocytes through regulation of cAMP-dependent protein kinase RIalpha.

PubMed

Johansson, C Christian; Dahle, Maria K; Blomqvist, Sandra Rodrigo; Grønning, Line M; Aandahl, Einar M; Enerbäck, Sven; Taskén, Kjetil

2003-05-09

Forkhead/winged helix (FOX) transcription factors are essential for control of the cell cycle and metabolism. Here, we show that spleens from Mf2-/- (FOXD2-/-) mice have reduced mRNA (50%) and protein (35%) levels of the RIalpha subunit of the cAMP-dependent protein kinase. In T cells from Mf2-/- mice, reduced levels of RIalpha translates functionally into approximately 2-fold less sensitivity to cAMP-mediated inhibition of proliferation triggered through the T cell receptor-CD3 complex. In Jurkat T cells, FOXD2 overexpression increased the endogenous levels of RIalpha through induction of the RIalpha1b promoter. FOXD2 overexpression also increased the sensitivity of the promoter to cAMP. Finally, co-expression experiments demonstrated that protein kinase Balpha/Akt1 work together with FOXD2 to induce the RIalpha1b promoter (10-fold) and increase endogenous RIalpha protein levels further. Taken together, our data indicate that FOXD2 is a physiological regulator of the RIalpha1b promoter in vivo working synergistically with protein kinase B to induce cAMP-dependent protein kinase RIalpha expression, which increases cAMP sensitivity and sets the threshold for cAMP-mediated negative modulation of T cell activation.

Developing Highly Sensitive Micro-Biosensors for in-situ Monitoring Mercury and Chromium(IV) Contaminants by Genetically-evolving and Computer-designing Metal-binding Proteins

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

Wang, Qinghong; Fang, Xiangdong; Goddard, William

2013-10-17

Mercury has been well known as an environmental pollutant to the environment and to cause serious effects on human health for several decades. To effectively control mercury pollution and reduce mercury damages, the sensitive determination of mercury is essential. Currently, many different types of sensor-based assays have been developed, while the whole-cell biosensor has been gaining increasingly attentions due to its easy reproducibility and the possibility to greatly reduce the cost. However, significant improvements on the specificity, sensitivity, stability and simplicity of the whole-cell biosensor are still needed prior to its eventual commercialization. Sponsored by US Department of Energy undermore » the contract agreement DE-FG02-07ER64410, we applied the special synthetic biology and directed evolution strategies to improve the effectiveness and performance of whole-cell biosensors. We have constructed different whole-cell biosensors for the mercuric ion and methylmercury detection with metalloregulator MerR, fluorescent protein mCherry and organomercurial lyase MerB. By introducing the mercuric transporter MerT, we were able to increase the detection sensitivity of whole-cell biosensors by at least one fold. By introducing the bio-amplification genetic circuit based on the gene cascade expression system of PRM-cI from bacteriophage l and Pm-XylS2 from Pseudomonas putida, we have increased the detection sensitivity of whole-cell biosensors by 1~2 folds in our tested conditions. With the directed evolution of MerR and subsequent high-throughput screening via color assay and microplate screening, we have dramatically increased the detection sensitivity by up to 10 folds at low concentration of mercury (II) of 1-10nM. Structural modeling and computational analysis of the mutated MerR showed that many mutations could cause the change of a loop to helix, which could be responsible for the increased mercury sensitivity.« less

Improving the performance of a pyramid wavefront sensor with modal sensitivity compensation.

PubMed

Korkiakoski, Visa; Vérinaud, Christophe; Le Louarn, Miska

2008-01-01

We describe a solution to increase the performance of a pyramid wavefront sensor (P-WFS) under bad seeing conditions. We show that most of the issues involve a reduced sensitivity that depends on the magnitude of the high frequency atmospheric distortions. We demonstrate in end-to-end closed loop adaptive optics simulations that with a modal sensitivity compensation method a high-order system with a nonmodulated P-WFS is robust in conditions with the Fried parameter r 0 at 0.5 microm in the range of 0.05-0.10 m. We also show that the method makes it possible to use a modal predictive control system to reach a total performance improvement of 0.06-0.45 in Strehl ratio at 1.6 microm. Especially at r 0=0.05 m the gain is dramatic.

Yellow filters can improve magnocellular function: motion sensitivity, convergence, accommodation, and reading.

PubMed

Ray, N J; Fowler, S; Stein, J F

2005-04-01

The magnocellular system plays an important role in visual motion processing, controlling vergence eye movements, and in reading. Yellow filters may boost magnocellular activity by eliminating inhibitory blue input to this pathway. It was found that wearing yellow filters increased motion sensitivity, convergence, and accommodation in many children with reading difficulties, both immediately and after three months using the filters. Motion sensitivity was not increased using control neutral density filters. Moreover, reading-impaired children showed significant gains in reading ability after three months wearing the filters compared with those who had used a placebo. It was concluded that yellow filters can improve magnocellular function permanently. Hence, they should be considered as an alternative to corrective lenses, prisms, or exercises for treating poor convergence and accommodation, and also as an aid for children with reading problems.

Sensitivity and Calibration of Non-Destructive Evaluation Method That Uses Neural-Net Processing of Characteristic Fringe Patterns

NASA Technical Reports Server (NTRS)

Decker, Arthur J.; Weiland, Kenneth E.

2003-01-01

This paper answers some performance and calibration questions about a non-destructive-evaluation (NDE) procedure that uses artificial neural networks to detect structural damage or other changes from sub-sampled characteristic patterns. The method shows increasing sensitivity as the number of sub-samples increases from 108 to 6912. The sensitivity of this robust NDE method is not affected by noisy excitations of the first vibration mode. A calibration procedure is proposed and demonstrated where the output of a trained net can be correlated with the outputs of the point sensors used for vibration testing. The calibration procedure is based on controlled changes of fastener torques. A heterodyne interferometer is used as a displacement sensor for a demonstration of the challenges to be handled in using standard point sensors for calibration.

The orexin component of fasting triggers memory processes underlying conditioned food selection in the rat.

PubMed

Ferry, Barbara; Duchamp-Viret, Patricia

2014-03-14

To test the selectivity of the orexin A (OXA) system in olfactory sensitivity, the present study compared the effects of fasting and of central infusion of OXA on the memory processes underlying odor-malaise association during the conditioned odor aversion (COA) paradigm. Animals implanted with a cannula in the left ventricle received ICV infusion of OXA or artificial cerebrospinal fluid (ACSF) 1 h before COA acquisition. An additional group of intact rats were food-deprived for 24 h before acquisition. Results showed that the increased olfactory sensitivity induced by fasting and by OXA infusion was accompanied by enhanced COA performance. The present results suggest that fasting-induced central OXA release influenced COA learning by increasing not only olfactory sensitivity, but also the memory processes underlying the odor-malaise association.

The orexin component of fasting triggers memory processes underlying conditioned food selection in the rat

PubMed Central

Ferry, Barbara; Duchamp-Viret, Patricia

2014-01-01

To test the selectivity of the orexin A (OXA) system in olfactory sensitivity, the present study compared the effects of fasting and of central infusion of OXA on the memory processes underlying odor–malaise association during the conditioned odor aversion (COA) paradigm. Animals implanted with a cannula in the left ventricle received ICV infusion of OXA or artificial cerebrospinal fluid (ACSF) 1 h before COA acquisition. An additional group of intact rats were food-deprived for 24 h before acquisition. Results showed that the increased olfactory sensitivity induced by fasting and by OXA infusion was accompanied by enhanced COA performance. The present results suggest that fasting-induced central OXA release influenced COA learning by increasing not only olfactory sensitivity, but also the memory processes underlying the odor–malaise association. PMID:24634353

Coupled resonator optical waveguide sensors: sensitivity and the role of slow light

NASA Astrophysics Data System (ADS)

Terrel, Matthew A.; Digonnet, Michel J. F.; Fan, Shanhui

2009-05-01

We compare the sensitivity of two configurations of coupled resonator optical waveguide (CROW) gyroscopes proposed by others to conventional optical gyroscopes. In both cases, we demonstrate that for equal device footprint and loss, neither of these CROW gyroscopes configurations is more sensitive than its conventional counterpart. In all cases, loss ultimately limits the maximum rotation sensitivity. The fact that light travels more slowly (i.e., with a greater group delay) in a CROW than in a fiber therefore has no effect on sensitivity. The only benefit slow light does have is that it reduces the device length requirement, or equivalently it increases the sensitivity per unit length. However, we show that this improvement is quantitatively the same as in an RFOG. These conclusions are not limited to these two CROW configurations or to rotation sensing, but applicable to any measurand that modifies the phase of the signal(s) traveling in the resonators.

East-West Cultural Differences in Context-sensitivity are Evident in Early Childhood

PubMed Central

Imada, Toshie; Carlson, Stephanie M.; Itakura, Shoji

2018-01-01

Accumulating evidence suggests North Americans tend to focus on central objects whereas East Asians tend to pay more attention to contextual information in a visual scene. Although it is generally believed that such culturally divergent attention tendencies develop through socialization, existing evidence largely depends on adult samples. Moreover, no past research has investigated the relation between context-sensitivity and other domains of cognitive development. The present study investigated children in the United States and Japan (N = 175, age 4–9 years) to examine the developmental pattern in context-sensitivity and its relation to executive function. The study found that context-sensitivity increased with age across cultures. Nevertheless, Japanese children showed significantly greater context-sensitivity than American children. Also, context-sensitivity fully mediated the cultural difference in a set-shifting executive function task, which might help explain past findings that East-Asian children outperformed their American counterparts on executive function. PMID:23432830

Antibody mechanisms implicated in digestive disturbances following ingestion of soya protein in calves and piglets.

PubMed Central

Barratt, M E; Strachan, P J; Porter, P

1978-01-01

Serum antibody responses to ingested aqueous alcohol-extracted soya proteins were studied in thirty-six pre-ruminant calves. Characterization of this antibody showed it to be predominantly a complement-fixing IgG1 preciptin. No evidence of tolerance was seen; previously sensitized calves responded to reintroduction of a soya diet with marked increases in antibody levels. The soya antigen was shown to be resistant to proteolysis and, to a lesser degree, to the microbial action of rumen fluid. Biopsy studies showed that the feeding of soya protein resulted in morphological disturbances to the villi and lamina propria of the intestine. Physiological studies by Thirty-Vella loop perfusion in the pig showed that soya protein solutions resulted in significant inhibition of flow rates. The effect was only observed after previous sensitization with the soya antigen. This study shows the necessity of applying immunological criteria to the quality control of soya bean processing in order to ensure that the sensitizing agent is eliminated and the nutritional qualities of soya protein concentrates are optimized. Images FIG. 2a FIG. 2b PMID:565686

An electrophysiological investigation of the receptor apparatus of the duck's bill

PubMed Central

Gregory, J. E.

1973-01-01

1. The properties of receptors in the duck's bill have been studied by recording from units isolated by dissecting fine filaments from the maxillary and ophthalmic nerves. 2. The units studied were divisible into three groups, phasic mechanoreceptors responsive to vibration, thermoreceptive units, and high threshold mechanoreceptors. 3. Vibration-sensitive mechanoreceptors (113 units) had small receptive fields, showed a rapidly adapting discharge to mechanical stimulation of the bill, were sensitive to vibratory but not to thermal stimuli and showed no background discharge. 4. Temperature receptors (twenty-one units) were insensitive to mechanical stimulation and showed a temperature-dependent background discharge. Sudden cooling produced a transient increase in discharge frequency. 5. High threshold mechanosensitive units (eight units) gave a slowly adapting discharge to strong mechanical stimulation and were insensitive to vibratory and thermal stimulation. 6. It is concluded that the low-threshold, vibration-sensitive responses come from Herbst corpuscles. No specific function can yet be assigned to the Grandry corpuscles. PMID:4689962

Identifying Candidate Genes that Underlie Cellular pH Sensitivity in Serotonin Neurons Using Transcriptomics: A Potential Role for Kir5.1 Channels

PubMed Central

Puissant, Madeleine M.; Mouradian, Gary C.; Liu, Pengyuan; Hodges, Matthew R.

2017-01-01

Ventilation is continuously adjusted by a neural network to maintain blood gases and pH. Acute CO2 and/or pH regulation requires neural feedback from brainstem cells that encode CO2/pH to modulate ventilation, including but not limited to brainstem serotonin (5-HT) neurons. Brainstem 5-HT neurons modulate ventilation and are stimulated by hypercapnic acidosis, the sensitivity of which increases with increasing postnatal age. The proper function of brainstem 5-HT neurons, particularly during post-natal development is critical given that multiple abnormalities in the 5-HT system have been identified in victims of Sudden Infant Death Syndrome. Here, we tested the hypothesis that there are age-dependent increases in expression of pH-sensitive ion channels in brainstem 5-HT neurons, which may underlie their cellular CO2/pH sensitivity. Midline raphe neurons were acutely dissociated from neonatal and mature transgenic SSePet-eGFP rats [which have enhanced green fluorescent protein (eGFP) expression in all 5-HT neurons] and sorted with fluorescence-activated cell sorting (FACS) into 5-HT-enriched and non-5-HT cell pools for subsequent RNA extraction, cDNA library preparation and RNA sequencing. Overlapping differential expression analyses pointed to age-dependent shifts in multiple ion channels, including but not limited to the pH-sensitive potassium ion (K+) channel genes kcnj10 (Kir4.1), kcnj16 (Kir5.1), kcnk1 (TWIK-1), kcnk3 (TASK-1) and kcnk9 (TASK-3). Intracellular contents isolated from single adult eGFP+ 5-HT neurons confirmed gene expression of Kir4.1, Kir5.1 and other K+ channels, but also showed heterogeneity in the expression of multiple genes. 5-HT neuron-enriched cell pools from selected post-natal ages showed increases in Kir4.1, Kir5.1, and TWIK-1, fitting with age-dependent increases in Kir4.1 and Kir5.1 protein expression in raphe tissue samples. Immunofluorescence imaging confirmed Kir5.1 protein was co-localized to brainstem neurons and glia including 5-HT neurons as expected. However, Kir4.1 protein expression was restricted to glia, suggesting that it may not contribute to 5-HT neuron pH sensitivity. Although there are caveats to this approach, the data suggest that pH-sensitive Kir5.1 channels may underlie cellular CO2/pH chemosensitivity in brainstem 5-HT neurons. PMID:28270749

Dependence of sea-surface microwave emissivity on friction velocity as derived from SMMR/SASS

NASA Technical Reports Server (NTRS)

Wentz, F. J.; Christensen, E. J.; Richardson, K. A.

1981-01-01

The sea-surface microwave emissivity is derived using SMMR brightness temperatures and SASS inferred friction velocities for three North Pacific Seasat passes. The results show the emissivity increasing linearly with friction velocity with no obvious break between the foam-free and foam regimes up to a friction velocity of about 70 cm/sec (15 m/sec wind speed). For horizontal polarization the sensitivity of emissivity to friction velocity greatly increases with frequency, while for vertical polarization the sensitivity is much less and is independent of frequency. This behavior is consistent with two-scale scattering theory. A limited amount of high friction velocity data above 70 cm/sec suggests an additional increase in emissivity due to whitecapping.

Eating high fat chow increases the sensitivity of rats to 8-OH-DPAT-induced lower lip retraction.

PubMed

Li, Jun-Xu; Ju, Shutian; Baladi, Michelle G; Koek, Wouter; France, Charles P

2011-12-01

Eating high fat food can alter sensitivity to drugs acting on dopamine systems; this study examined whether eating high fat food alters sensitivity to a drug acting on serotonin (5-HT) systems. Sensitivity to (+)-8-hydroxy-2-(dipropylamino) tetralin hydrobromide (8-OH-DPAT; 5-HT1A receptor agonist)-induced lower lip retraction was examined in separate groups (n=8-9) of rats with free access to standard (5.7% fat) or high fat (34.3% fat) chow; sensitivity to quinpirole (dopamine D3/D2 receptor agonist)-induced yawning was also examined. Rats eating high fat chow gained more body weight than rats eating standard chow and, after 6 weeks of eating high fat chow, they were more sensitive to 8-OH-DPAT (0.01-0.1 mg/kg)-induced lower lip retraction and quinpirole (0.0032-0.32 mg/kg)-induced yawning. These changes were not reversed when rats that previously ate high fat chow were switched to eating standard chow and sensitivity to 8-OH-DPAT and quinpirole increased when rats that previously ate standard chow ate high fat chow. These data extend previous results showing changes in sensitivity to drugs acting on dopamine systems in animals eating high fat chow to a drug acting at 5-HT1A receptors and they provide support for the notion that eating certain foods impacts sensitivity to drugs acting on monoamine systems.

Eating high fat chow increases the sensitivity of rats to 8-OH-DPAT-induced lower lip retraction

PubMed Central

Li, Jun-Xu; Ju, Shutian; Baladi, Michelle G; Koek, Wouter; France, Charles P

2011-01-01

Eating high fat food can alter sensitivity to drugs acting on dopamine systems; this study examined whether eating high fat food alters sensitivity to a drug acting on serotonin (5-HT) systems. Sensitivity to (+)-8-hydroxy-2-(dipropylamino) tetralin hydrobromide (8-OH-DPAT; 5-HT1A receptor agonist)-induced lower lip retraction was examined in separate groups (n=8-9) of rats with free access to standard (5.7% fat) or high fat (34.3% fat) chow; sensitivity to quinpirole (dopamine D3/D2 receptor agonist)-induced yawning was also examined. Rats eating high fat chow gained more body weight than rats eating standard chow and, after 6 weeks of eating high fat chow, they were more sensitive to 8-OH-DPAT (0.01-0.1 mg/kg)-induced lower lip retraction and quinpirole (0.0032-0.32 mg/kg)-induced yawning. These changes were not reversed when rats that previously ate high fat chow were switched to eating standard chow and sensitivity to 8-OH-DPAT and quinpirole increased when rats that previously ate standard chow ate high fat chow. These data extend previous results showing changes in sensitivity to drugs acting on dopamine systems in animals eating high fat chow to a drug acting at 5-HT1A receptors and they provide support for the notion that eating certain foods impacts sensitivity to drugs acting on monoamine systems. PMID:21979831

Climate Sensitivity, Sea Level, and Atmospheric Carbon Dioxide

NASA Technical Reports Server (NTRS)

Hansen, James; Sato, Makiko; Russell, Gary; Kharecha, Pushker

2013-01-01

Cenozoic temperature, sea level and CO2 covariations provide insights into climate sensitivity to external forcings and sea-level sensitivity to climate change. Climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise palaeoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity of 3+/-1deg C for a 4 W/sq m CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene. Glacial-to-interglacial climate change leading to the prior (Eemian) interglacial is less ambiguous and implies a sensitivity in the upper part of the above range, i.e. 3-4deg C for a 4 W/sq m CO2 forcing. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify the total Earth system sensitivity by an amount that depends on the time scale considered. Ice sheet response time is poorly defined, but we show that the slow response and hysteresis in prevailing ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state dependence of climate sensitivity, finding an increased sensitivity towards warmer climates, as low cloud cover is diminished and increased water vapour elevates the tropopause. Burning all fossil fuels, we conclude, would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change.

Acute subjective response to alcohol as a function of reward and punishment sensitivity.

PubMed

Morris, David H; Treloar, Hayley; Tsai, Chia-Lin; McCarty, Kayleigh N; McCarthy, Denis M

2016-09-01

Individual differences in subjective response to alcohol play a crucial role in the development of heavy drinking and related problems. In light of this, a growing focus of research has been identifying factors that contribute to differences in response. The aim of the present study was to determine whether individual differences in the subjective experience of rewarding and aversive effects of alcohol are a specific manifestation of general differences in reward and punishment sensitivity. Eighty-nine participants (M age=22.4, SD=1.9; 47.2% women) consumed a moderate dose of alcohol, i.e., peak breath alcohol concentration (BrAC)≈0.080g%, and rated their level of stimulation and sedation at seven timepoints over the BrAC curve. Sensitivity to reward and punishment were assessed by a self-report questionnaire prior to consumption. Multilevel growth models showed that post-consumption changes in stimulation ratings varied as a function of participants' level of reward and punishment sensitivity. Drinkers more sensitive to reward reported feeling more stimulated shortly after drinking and exhibited an attenuated rate of decline in stimulation over the blood alcohol curve, relative to drinkers with less strong reward sensitivity. Reward sensitivity was not related to subjective ratings of sedation, and punishment sensitivity was not related to either stimulation or sedation ratings. Findings suggest that reward sensitivity may increase risk for alcohol misuse among young adult social drinkers by increasing their subjective feelings of stimulation while drinking. Copyright © 2016. Published by Elsevier Ltd.

Direct-write nanoscale printing of nanogranular tunnelling strain sensors for sub-micrometre cantilevers

PubMed Central

Dukic, Maja; Winhold, Marcel; Schwalb, Christian H.; Adams, Jonathan D.; Stavrov, Vladimir; Huth, Michael; Fantner, Georg E.

2016-01-01

The sensitivity and detection speed of cantilever-based mechanical sensors increases drastically through size reduction. The need for such increased performance for high-speed nanocharacterization and bio-sensing, drives their sub-micrometre miniaturization in a variety of research fields. However, existing detection methods of the cantilever motion do not scale down easily, prohibiting further increase in the sensitivity and detection speed. Here we report a nanomechanical sensor readout based on electron co-tunnelling through a nanogranular metal. The sensors can be deposited with lateral dimensions down to tens of nm, allowing the readout of nanoscale cantilevers without constraints on their size, geometry or material. By modifying the inter-granular tunnel-coupling strength, the sensors' conductivity can be tuned by up to four orders of magnitude, to optimize their performance. We show that the nanoscale printed sensors are functional on 500 nm wide cantilevers and that their sensitivity is suited even for demanding applications such as atomic force microscopy. PMID:27666316

The efficacy of VIPP-V parenting training for parents of young children with a visual or visual-and-intellectual disability: a randomized controlled trial.

PubMed

Platje, Evelien; Sterkenburg, Paula; Overbeek, Mathile; Kef, Sabina; Schuengel, Carlo

2018-01-23

Video-feedback Intervention to promote positive parenting-visual (VIPP-V) or visual-and-intellectual disability is an attachment-based intervention aimed at enhancing sensitive parenting and promoting positive parent-child relationships. A randomized controlled trial was conducted to assess the efficacy of VIPP-V for parents of children aged 1-5 with visual or visual-and-intellectual disabilities. A total of 37 dyads received only care-as-usual (CAU) and 40 received VIPP-V besides CAU. The parents receiving VIPP-V did not show increased parental sensitivity or parent-child interaction quality, however, their parenting self-efficacy increased. Moreover, the increase in parental self-efficacy predicted the increase in parent-child interaction. In conclusion, VIPP-V does not appear to directly improve the quality of contact between parent and child, but does contribute to the self-efficacy of parents to support and to comfort their child. Moreover, as parents experience their parenting as more positive, this may eventually lead to higher sensitive responsiveness and more positive parent-child interactions.

Sickle Mice Are Sensitive to Hypoxia/Ischemia-Induced Stroke but Respond to Tissue-Type Plasminogen Activator Treatment.

PubMed

Sun, Yu-Yo; Lee, Jolly; Huang, Henry; Wagner, Mary B; Joiner, Clinton H; Archer, David R; Kuan, Chia-Yi

2017-12-01

The effects of lytic stroke therapy in patients with sickle cell anemia are unknown, although a recent study suggested that coexistent sickle cell anemia does not increase the risk of cerebral hemorrhage. This finding calls for systemic analysis of the effects of thrombolytic stroke therapy, first in humanized sickle mice, and then in patients. There is also a need for additional predictive markers of sickle cell anemia-associated vasculopathy. We used Doppler ultrasound to examine the carotid artery of Townes sickle mice tested their responses to repetitive mild hypoxia-ischemia- and transient hypoxia-ischemia-induced stroke at 3 or 6 months of age, respectively. We also examined the effects of tPA (tissue-type plasminogen activator) treatment in transient hypoxia-ischemia-injured sickle mice. Three-month-old sickle cell (SS) mice showed elevated resistive index in the carotid artery and higher sensitivity to repetitive mild hypoxia-ischemia-induced cerebral infarct. Six-month-old SS mice showed greater resistive index and increased flow velocity without obstructive vasculopathy in the carotid artery. Instead, the cerebral vascular wall in SS mice showed ectopic expression of PAI-1 (plasminogen activator inhibitor-1) and P-selectin, suggesting a proadhesive and prothrombotic propensity. Indeed, SS mice showed enhanced leukocyte and platelet adherence to the cerebral vascular wall, broader fibrin deposition, and higher mortality after transient hypoxia-ischemia. Yet, post-transient hypoxia-ischemia treatment with tPA reduced thrombosis and mortality in SS mice. Sickle mice are sensitive to hypoxia/ischemia-induced cerebral infarct but benefit from thrombolytic treatment. An increased resistive index in carotid arteries may be an early marker of sickle cell vasculopathy. © 2017 American Heart Association, Inc.

Differential housing and novelty response: Protection and risk from locomotor sensitization

PubMed Central

Garcia, Erik J.; Haddon, Tara N.; Saucier, Donald A.; Cain, Mary E.

2017-01-01

High novelty seeking increases the risk for drug experimentation and locomotor sensitization. Locomotor sensitization to psychostimulants is thought to reflect neurological adaptations that promote the transition to compulsive drug taking. Rats reared in enrichment (EC) show less locomotor sensitization when compared to rats reared in isolation (IC) or standard conditions (SC). The current research study was designed to test if novelty response contributed locomotor sensitization and more importantly, if the different housing environments could change the novelty response to protect against the development of locomotor sensitization in both adolescence and adulthood. Experiment 1: rats were tested for their response to novelty using the inescapable novelty test (IEN) and pseudorandomly assigned to enriched (EC), isolated (IC), or standard (SC) housing conditions for 30 days. After housing, they were tested with IEN. Rats were then administered amphetamine (0.5 mg/kg) or saline and locomotor activity was measured followed by a sensitization test 14 days later. Experiment 2: rats were tested in the IEN test early adulthood and given five administrations of amphetamine (0.3 mg/kg) or saline and then either stayed in or switched housing environments for 30 days. Rats were then re-tested in the IEN test in late adulthood and administered five more injections of their respective treatments and tested for locomotor sensitization. Results indicate that IC and SC increased the response to novelty. EC housing decreased locomotor response to amphetamine and saline, and SC housing increased the locomotor response to amphetamine. Mediation results indicated that the late adult novelty response fully mediates the locomotor response to amphetamine and saline, while the early adulthood novelty response did not. Conclusions Differential housing changes novelty and amphetamine locomotor response. Novelty response is altered into adulthood and provides evidence that enrichment can be used to reduce drug vulnerability. PMID:28108176

Regulatory cells induced by acute toxoplasmosis prevent the development of allergic lung inflammation.

PubMed

Fenoy, Ignacio M; Sanchez, Vanesa R; Soto, Ariadna S; Picchio, Mariano S; Maglioco, Andrea; Corigliano, Mariana G; Dran, Graciela I; Martin, Valentina; Goldman, Alejandra

2015-05-01

The increased prevalence of allergies in developed countries has been attributed to a reduction of some infections. Supporting epidemiological studies, we previously showed that both acute and chronic Toxoplasma gondii infection can diminish allergic airway inflammation in BALB/c mice. The mechanisms involved when sensitization occurs during acute phase would be related to the strong Th1 response induced by the parasite. Here, we further investigated the mechanisms involved in T. gondii allergy protection in mice sensitized during acute T. gondii infection. Adoptive transference assays and ex vivo co-cultures experiments showed that not only thoracic lymph node cells from infected and sensitized mice but also from non-sensitized infected animals diminished both allergic lung inflammation and the proliferation of effector T cells from allergic mice. This ability was found to be contact-independent and correlated with high levels of CD4(+)FoxP3(+) cells. IL-10 would not be involved in allergy suppression since IL-10-deficient mice behaved similar to wild type mice. Our results extend earlier work and show that, in addition to immune deviation, acute T. gondii infection can suppress allergic airway inflammation through immune suppression. Copyright © 2014 Elsevier GmbH. All rights reserved.

Sensitivity for Cues Predicting Reward and Punishment in Young Women with Eating Disorders.

PubMed

Matton, Annelies; de Jong, Peter; Goossens, Lien; Jonker, Nienke; Van Malderen, Eva; Vervaet, Myriam; De Schryver, Nele; Braet, Caroline

2017-11-01

Increasing evidence shows that sensitivity to reward (SR) and punishment (SP) may be involved in eating disorders (EDs). Most studies used self-reported positive/negative effect in rewarding/punishing situations, whereas the implied proneness to detect signals of reward/punishment is largely ignored. This pilot study used a spatial orientation task to examine transdiagnostic and interdiagnostic differences in SR/SP. Participants (14-29 years) were patients with anorexia nervosa of restricting type (AN-R, n = 20), binge/purge ED group [AN of binge/purge type and bulimia nervosa (n = 16)] and non-symptomatic individuals (n = 23). Results revealed stronger difficulties to redirect attention away from signals of rewards in AN-R compared with binge/purge EDs, and binge/purge EDs showed stronger difficulties to direct attention away from signals of punishment compared with AN-R. Findings demonstrate interdiagnostic differences and show that the spatial orientation task is sensitive for individual differences in SP/SR within the context of EDs, thereby sustaining its usefulness as behavioural measure of reinforcement sensitivity. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

Effects of anxiety sensitivity and expectations on the modulation of the startle eyeblink response during a caffeine challenge.

PubMed

Benke, Christoph; Blumenthal, Terry D; Modeß, Christiane; Hamm, Alfons O; Pané-Farré, Christiane A

2015-09-01

The way in which the tendency to fear somatic arousal sensations (anxiety sensitivity), in interaction with the created expectations regarding arousal induction, might affect defensive responding to a symptom provocation challenge is not yet understood. The present study investigated the effect of anxiety sensitivity on autonomic arousal, startle eyeblink responses, and reported arousal and alertness to expected vs. unexpected caffeine consumption. To create a match/mismatch of expected and experienced arousal, high and low anxiety sensitive participants received caffeine vs. no drug either mixed in coffee (expectation of arousal induction) or in bitter lemon soda (no expectation of arousal induction) on four separate occasions. Autonomic arousal (heart rate, skin conductance level), respiration (end-tidal CO2, minute ventilation), defensive reflex responses (startle eyeblink), and reported arousal and alertness were recorded prior to, immediately and 30 min after beverage ingestion. Caffeine increased ventilation, autonomic arousal, and startle response magnitudes. Both groups showed comparable levels of autonomic and respiratory responses. The startle eyeblink responses were decreased when caffeine-induced arousal occurred unexpectedly, e.g., after administering caffeine in bitter lemon. This effect was more accentuated in high anxiety sensitive persons. Moreover, in high anxiety sensitive persons, the expectation of arousal (coffee consumption) led to higher subjective alertness when administering caffeine and increased arousal even if no drug was consumed. Unexpected symptom provocation leads to increased attention allocation toward feared arousal sensations in high anxiety sensitive persons. This finding broadens our understanding of modulatory mechanisms in defensive responding to bodily symptoms.

Modeling the Sensitivity of Field Surveys for Detection of Environmental DNA (eDNA)

PubMed Central

Schultz, Martin T.; Lance, Richard F.

2015-01-01

The environmental DNA (eDNA) method is the practice of collecting environmental samples and analyzing them for the presence of a genetic marker specific to a target species. Little is known about the sensitivity of the eDNA method. Sensitivity is the probability that the target marker will be detected if it is present in the water body. Methods and tools are needed to assess the sensitivity of sampling protocols, design eDNA surveys, and interpret survey results. In this study, the sensitivity of the eDNA method is modeled as a function of ambient target marker concentration. The model accounts for five steps of sample collection and analysis, including: 1) collection of a filtered water sample from the source; 2) extraction of DNA from the filter and isolation in a purified elution; 3) removal of aliquots from the elution for use in the polymerase chain reaction (PCR) assay; 4) PCR; and 5) genetic sequencing. The model is applicable to any target species. For demonstration purposes, the model is parameterized for bighead carp (Hypophthalmichthys nobilis) and silver carp (H. molitrix) assuming sampling protocols used in the Chicago Area Waterway System (CAWS). Simulation results show that eDNA surveys have a high false negative rate at low concentrations of the genetic marker. This is attributed to processing of water samples and division of the extraction elution in preparation for the PCR assay. Increases in field survey sensitivity can be achieved by increasing sample volume, sample number, and PCR replicates. Increasing sample volume yields the greatest increase in sensitivity. It is recommended that investigators estimate and communicate the sensitivity of eDNA surveys to help facilitate interpretation of eDNA survey results. In the absence of such information, it is difficult to evaluate the results of surveys in which no water samples test positive for the target marker. It is also recommended that invasive species managers articulate concentration-based sensitivity objectives for eDNA surveys. In the absence of such information, it is difficult to design appropriate sampling protocols. The model provides insights into how sampling protocols can be designed or modified to achieve these sensitivity objectives. PMID:26509674

Modeling the Sensitivity of Field Surveys for Detection of Environmental DNA (eDNA).

PubMed

Schultz, Martin T; Lance, Richard F

2015-01-01

The environmental DNA (eDNA) method is the practice of collecting environmental samples and analyzing them for the presence of a genetic marker specific to a target species. Little is known about the sensitivity of the eDNA method. Sensitivity is the probability that the target marker will be detected if it is present in the water body. Methods and tools are needed to assess the sensitivity of sampling protocols, design eDNA surveys, and interpret survey results. In this study, the sensitivity of the eDNA method is modeled as a function of ambient target marker concentration. The model accounts for five steps of sample collection and analysis, including: 1) collection of a filtered water sample from the source; 2) extraction of DNA from the filter and isolation in a purified elution; 3) removal of aliquots from the elution for use in the polymerase chain reaction (PCR) assay; 4) PCR; and 5) genetic sequencing. The model is applicable to any target species. For demonstration purposes, the model is parameterized for bighead carp (Hypophthalmichthys nobilis) and silver carp (H. molitrix) assuming sampling protocols used in the Chicago Area Waterway System (CAWS). Simulation results show that eDNA surveys have a high false negative rate at low concentrations of the genetic marker. This is attributed to processing of water samples and division of the extraction elution in preparation for the PCR assay. Increases in field survey sensitivity can be achieved by increasing sample volume, sample number, and PCR replicates. Increasing sample volume yields the greatest increase in sensitivity. It is recommended that investigators estimate and communicate the sensitivity of eDNA surveys to help facilitate interpretation of eDNA survey results. In the absence of such information, it is difficult to evaluate the results of surveys in which no water samples test positive for the target marker. It is also recommended that invasive species managers articulate concentration-based sensitivity objectives for eDNA surveys. In the absence of such information, it is difficult to design appropriate sampling protocols. The model provides insights into how sampling protocols can be designed or modified to achieve these sensitivity objectives.

The relationship of thioredoxin-1 and cisplatin resistance: its impact on ROS and oxidative metabolism in lung cancer cells.

PubMed

Wangpaichitr, Medhi; Sullivan, Elizabeth J; Theodoropoulos, George; Wu, Chunjing; You, Min; Feun, Lynn G; Lampidis, Theodore J; Kuo, Macus T; Savaraj, Niramol

2012-03-01

Elimination of cisplatin-resistant lung cancer cells remains a major obstacle. We have shown that cisplatin-resistant tumors have higher reactive oxygen species (ROS) levels and can be exploited for targeted therapy. Here, we show that increased secretion of the antioxidant thioredoxin-1 (TRX1) resulted in lowered intracellular TRX1 and contributed to higher ROS in cisplatin-resistant tumors in vivo and in vitro. By reconstituting TRX1 protein in cisplatin-resistant cells, we increased sensitivity to cisplatin but decreased sensitivity to elesclomol (ROS inducer). Conversely, decreased TRX1 protein in parental cells reduced the sensitivity to cisplatin but increased sensitivity to elesclomol. Cisplatin-resistant cells had increased endogenous oxygen consumption and mitochondrial activity but decreased lactic acid production. They also exhibited higher levels of argininosuccinate synthetase (ASS) and fumarase mRNA, which contributed to oxidative metabolism (OXMET) when compared with parental cells. Restoring intracellular TRX1 protein in cisplatin-resistant cells resulted in lowering ASS and fumarase mRNAs, which in turn sensitized them to arginine deprivation. Interestingly, cisplatin-resistant cells also had significantly higher basal levels of acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS). Overexpressing TRX1 lowered ACC and FAS proteins expressions in cisplatin-resistant cells. Chemical inhibition and short interfering RNA of ACC resulted in significant cell death in cisplatin-resistant compared with parental cells. Conversely, TRX1 overexpressed cisplatin-resistant cells resisted 5-(tetradecyloxy)-2-furoic acid (TOFA)-induced death. Collectively, lowering TRX1 expression through increased secretion leads cisplatin-resistant cells to higher ROS production and increased dependency on OXMET. These changes raise an intriguing therapeutic potential for future therapy in cisplatin-resistant lung cancer.

The Relationship of Thioredoxin-1 and Cisplatin Resistance: Its Impact on ROS and Oxidative Metabolism in Lung Cancer Cells

PubMed Central

Wangpaichitr, Medhi; Theodoropoulos, George; Wu, Chunjing; You, Min; Feun, Lynn G.; Kuo, Macus T.; Savaraj, Niramol

2012-01-01

Elimination of cisplatin resistant (CR) lung cancer cells remains a major obstacle. We have shown that CR tumors have higher reactive oxygen species (ROS) levels and can be exploited for targeted therapy. Here we show that increased secretion of the antioxidant thioredoxin-1 (TRX1) resulted in lowered intracellular TRX1, and contributed to higher ROS in CR tumors in vivo and in vitro. By reconstitutingTRX1 protein in CR cells, we increased sensitivity to cisplatin but decreased sensitivity to elesclomol (ROS inducer). Conversely, decreased TRX1 protein in parental cells reduced the sensitivity to cisplatin but increased sensitivity to elesclomol. CR cells had increased endogenous oxygen consumption and mitochondrial activity but decreased lactic acid production. They also exhibited higher levels of argininosuccinate synthetase (ASS) and fumarase (FH) mRNA which contributed to oxidative metabolism (OXMET) when compared to parental cells. Restoring intracellular TRX1 protein in CR cells resulted in lowering ASS and FH mRNAs which in turn sensitized them to arginine deprivation. Interestingly, CR cells also possessed significantly higher basal levels of acetyl-CoA-carboxylase (ACC) and fatty acid synthase (FAS). Over-expressing TRX1 lowered ACC and FAS proteins expressions in CR cells. Chemical inhibition and siRNA of ACC resulted in significant cell death in CR compared to parental cells. Conversely, TRX1 over-expressed CR cells resisted to TOFA-induced death. Collectively, lowering TRX1 expression through increased secretion leads CR cells to higher ROS production and increase in dependency on OXMET. These changes raise an intriguing therapeutic potential for future therapy in cisplatin resistant lung cancer. PMID:22248473

Silicon nano-membrane based photonic crystal microcavities for high sensitivity bio-sensing.

PubMed

Lai, Wei-Cheng; Chakravarty, Swapnajit; Zou, Yi; Chen, Ray T

2012-04-01

We experimentally demonstrated photonic crystal microcavity based resonant sensors coupled to photonic crystal waveguides in silicon nano-membrane on insulator for chemical and bio-sensing. Linear L-type microcavities are considered. In contrast to cavities with small mode volumes, but low quality factors for bio-sensing, we showed increasing the length of the microcavity enhances the quality factor of the resonance by an order of magnitude and increases the resonance wavelength shift while retaining compact device characteristics. Q~26760 and sensitivity down to 15 ng/ml and ~110 pg/mm2 in bio-sensing was experimentally demonstrated on silicon-on-insulator devices.

Rapid-scan Fourier-transform coherent anti-Stokes Raman scattering spectroscopy with heterodyne detection.

PubMed

Hiramatsu, Kotaro; Luo, Yizhi; Ideguchi, Takuro; Goda, Keisuke

2017-11-01

High-speed Raman spectroscopy has become increasingly important for analyzing chemical dynamics in real time. To address the need, rapid-scan Fourier-transform coherent anti-Stokes Raman scattering (FT-CARS) spectroscopy has been developed to realize broadband CARS measurements at a scan rate of more than 20,000 scans/s. However, the detection sensitivity of FT-CARS spectroscopy is inherently low due to the limited number of photons detected during each scan. In this Letter, we show our experimental demonstration of enhanced sensitivity in rapid-scan FT-CARS spectroscopy by heterodyne detection. Specifically, we implemented heterodyne detection by superposing the CARS electric field with an external local oscillator (LO) for their interference. The CARS signal was amplified by simply increasing the power of the LO without the need for increasing the incident power onto the sample. Consequently, we achieved enhancement in signal intensity and the signal-to-noise ratio by factors of 39 and 5, respectively, compared to FT-CARS spectroscopy with homodyne detection. The sensitivity-improved rapid-scan FT-CARS spectroscopy is expected to enable the sensitive real-time observation of chemical dynamics in a broad range of settings, such as combustion engines and live biological cells.

Analysis of multimode BDK doped POF gratings for temperature sensing

NASA Astrophysics Data System (ADS)

Luo, Yanhua; Wu, Wenxuan; Wang, Tongxin; Cheng, Xusheng; Zhang, Qijin; Peng, Gang-Ding; Zhu, Bing

2012-10-01

We report a temperature sensor based on a Bragg grating written in a benzil dimethyl ketal (BDK) doped multimode (MM) polymer optical fiber (POF) for the first time to our knowledge. The thermal response was further analyzed in view of theory and experiment. In theory, with the order of the reflected mode increasing from 1st to 60th order, for MM silica fiber Bragg grating (FBG) the temperature sensitivity will increase linearly from 16.2 pm/°C to 17.5 pm/°C, while for MM polymer FBG the temperature sensitivity (absolute value) will increase linearly from -79.5 pm/°C to -104.4 pm/°C. In addition, temperature sensitivity of MM polymer FBG exhibits almost 1 order larger mode order dependence than that of MM silica FBG. In experiment, the Bragg wavelength shift will decline linearly as the temperature rises, contrary to that of MM silica FBG. The temperature sensitivity of MM polymer FBG is ranged from -0.097 nm/°C to -0.111 nm/°C, more than 8 times that of MM silica FBG, showing great potential used as a temperature sensor.

Cross-sensitization to Artemisia and Ambrosia pollen allergens in an area located outside of the current distribution range of Ambrosia.

PubMed

Grewling, Łukasz; Jenerowicz, Dorota; Bogawski, Paweł; Smith, Matt; Nowak, Małgorzata; Frątczak, Agata; Czarnecka-Operacz, Magdalena

2018-02-01

The role of long-distance transported (LDT) Ambrosia pollen in inducing new sensitization and affecting sensitization rates in Artemisia -sensitized patients is unclear. The aim of this study was to estimate the degree of cross-sensitization to Ambrosia/Artemisi a allergens in citizens of Poznan (Western Poland). This area is covered by extensive Artemisia populations but does not currently have local Ambrosia populations. Sera of 119 patients were tested by fluoroenzyme immunoassay (CAP-FEIA system) against pollen allergen extracts of Artemisia vulgaris and Ambrosia artemisiifolia , an allergenic component of A. vulgaris ( nArt v 1 ), and an allergenic component of A. artemisiifolia ( nAmb a 1 ). Skin prick tests (SPTs, n = 86) were performed with pollen allergen extracts of A. vulgaris and A. artemisiifolia . Artemisia and Ambrosia pollen in ambient air was collected (1996-2013) by a Hirst type volumetric trap sited at roof level (33 m). The SPT showed that the prevalence of sensitization to Ambrosia and Artemisia pollen exceeded 3.5%, and 10.5%, respectively. The measurements of IgE in blood serum (CAP-FEIA) revealed that among Ambrosia -sensitized patients 90.1% (20/22 patients) were concomitantly sensitized to Artemisia . 59.1% (13/22) of these patients reacted to nArt v 1 , suggesting primary sensitization to Artemisia pollen. Only 2 (9.1%) patients were mono-sensitized to Ambrosia pollen extract, but surprisingly not to nAmb a 1 . The LDT Ambrosia pollen had a negligible effect on the rate of sensitization to Ambrosia allergens in Poznan and did not increase the prevalence of sensitization to Artemisia pollen in this region. However, the majority of patients showing hypersensitization to Artemisia pollen might also present symptoms during elevated episodes of LDT of Ambrosia pollen.

Single prolonged stress effects on sensitization to cocaine and cocaine self-administration in rats

PubMed Central

Eagle, Andrew L.; Singh, Robby; Kohler, Robert J.; Friedman, Amy L.; Liebowitz, Chelsea P.; Galloway, Matthew P.; Enman, Nicole M.; Jutkiewicz, Emily M.; Perrine, Shane A.

2017-01-01

Posttraumatic stress disorder (PTSD) is often comorbid with substance use disorders (SUD). Single prolonged stress (SPS) is a well-validated rat model of PTSD that provides a framework to investigate drug-induced behaviors as a preclinical model of the comorbidity. We hypothesized that cocaine sensitization and self-administration would be increased following exposure to SPS. Male Sprague–Dawley rats were exposed to SPS or control treatment. After SPS, cocaine (0,10 or 20mg/kg, i.p.) was administered for 5 consecutive days and locomotor activity was measured. Another cohort was assessed for cocaine self-administration (0.1 or 0.32 mg/kg/i.v.) after SPS. Rats were tested for acquisition, extinction and cue-induced reinstatement behaviors. Control animals showed a dose-dependent increase in cocaine-induced locomotor activity after acute cocaine whereas SPS rats did not. Using a sub-threshold sensitization paradigm, control rats did not exhibit enhanced locomotor activity at Day 5 and therefore did not develop behavioral sensitization, asexpected. However, compared to control ratson Day 5 the locomotor response to 20mg/kg repeated cocaine was greatly enhanced in SPS-treated rats, which exhibited enhanced cocaine locomotor sensitization. The effect of SPS on locomotor activity was unique in that SPS did not modify cocaine self-administration behaviors under a simple schedule of reinforcement. These data show that SPS differentially affects cocaine-mediated behaviors causing no effect to cocaine self-administration, under a simple schedule of reinforcement, but significantly augmenting cocaine locomotor sensitization. These results suggest that SPS shares common neurocircuitry with stimulant-induced plasticity, but dissociable from that underlying psychostimulant-induced reinforcement. PMID:25712697

Dissociation between sensitization and learning-related neuromodulation in an aplysiid species.

PubMed

Erixon, N J; Demartini, L J; Wright, W G

1999-06-14

Previous phylogenetic analyses of learning and memory in an opisthobranch lineage uncovered a correlation between two learning-related neuromodulatory traits and their associated behavioral phenotypes. In particular, serotonin-induced increases in sensory neuron spike duration and excitability, which are thought to underlie several facilitatory forms of learning in Aplysia, appear to have been lost over the course of evolution in a distantly related aplysiid, Dolabrifera dolabrifera. This deficit is paralleled by a behavioral deficit: individuals of Dolabrifera do not express generalized sensitization (reflex enhancement of an unhabituated response after a noxious stimulus is applied outside of the reflex receptive field) or dishabituation (reflex enhancement of a habituated reflex). The goal of the present study was to confirm and extend this correlation by testing for the neuromodulatory traits and generalized sensitization in an additional species, Phyllaplysia taylori, which is closely related to Dolabrifera. Instead, our results indicated a lack of correlation between the neuromodulatory and behavioral phenotypes. In particular, sensory neuron homologues in Phyllaplysia showed the ancestral neuromodulatory phenotype typified by Aplysia. Bath-applied 10 microM serotonin significantly increased homologue spike duration and excitability. However, when trained with the identical apparatus and protocols that produced generalized sensitization in Aplysia, individuals of Phyllaplysia showed no evidence of sensitization. Thus, this species expresses the neuromodulatory phenotype of its ancestors while appearing to express the behavioral phenotype of its near relative. These results suggests that generalized sensitization can be lost during the course of evolution in the absence of a deficit in these two neuromodulatory traits, and raises the possibility that the two traits may support some other form of behavioral plasticity in Phyllaplysia. The results also raise the question of the mechanistic basis of the behavioral deficit in Phyllaplysia.

Single prolonged stress effects on sensitization to cocaine and cocaine self-administration in rats.

PubMed

Eagle, Andrew L; Singh, Robby; Kohler, Robert J; Friedman, Amy L; Liebowitz, Chelsea P; Galloway, Matthew P; Enman, Nicole M; Jutkiewicz, Emily M; Perrine, Shane A

2015-05-01

Posttraumatic stress disorder (PTSD) is often comorbid with substance use disorders (SUD). Single prolonged stress (SPS) is a well-validated rat model of PTSD that provides a framework to investigate drug-induced behaviors as a preclinical model of the comorbidity. We hypothesized that cocaine sensitization and self-administration would be increased following exposure to SPS. Male Sprague-Dawley rats were exposed to SPS or control treatment. After SPS, cocaine (0, 10 or 20 mg/kg, i.p.) was administered for 5 consecutive days and locomotor activity was measured. Another cohort was assessed for cocaine self-administration (0.1 or 0.32 mg/kg/i.v.) after SPS. Rats were tested for acquisition, extinction and cue-induced reinstatement behaviors. Control animals showed a dose-dependent increase in cocaine-induced locomotor activity after acute cocaine whereas SPS rats did not. Using a sub-threshold sensitization paradigm, control rats did not exhibit enhanced locomotor activity at Day 5 and therefore did not develop behavioral sensitization, as expected. However, compared to control rats on Day 5 the locomotor response to 20mg/kg repeated cocaine was greatly enhanced in SPS-treated rats, which exhibited enhanced cocaine locomotor sensitization. The effect of SPS on locomotor activity was unique in that SPS did not modify cocaine self-administration behaviors under a simple schedule of reinforcement. These data show that SPS differentially affects cocaine-mediated behaviors causing no effect to cocaine self-administration, under a simple schedule of reinforcement, but significantly augmenting cocaine locomotor sensitization. These results suggest that SPS shares common neurocircuitry with stimulant-induced plasticity, but dissociable from that underlying psychostimulant-induced reinforcement. Copyright © 2015. Published by Elsevier B.V.

MEK5/ERK5 signaling inhibition increases colon cancer cell sensitivity to 5-fluorouracil through a p53-dependent mechanism

PubMed Central

Pereira, Diane M.; Simões, André E. S.; Gomes, Sofia E.; Castro, Rui E.; Carvalho, Tânia; Rodrigues, Cecília M. P.; Borralho, Pedro M.

2016-01-01

The MEK5/ERK5 signaling pathway is emerging as an important contributor to colon cancer onset, progression and metastasis; however, its relevance to chemotherapy resistance remains unknown. Here, we evaluated the impact of the MEK5/ERK5 cascade in colon cancer cell sensitivity to 5-fluorouracil (5-FU). Increased ERK5 expression was correlated with poor overall survival in colon cancer patients. In colon cancer cells, 5-FU exposure impaired endogenous KRAS/MEK5/ERK5 expression and/or activation. In turn, MEK5 constitutive activation reduced 5-FU-induced cytotoxicity. Using genetic and pharmacological approaches, we showed that ERK5 inhibition increased caspase-3/7 activity and apoptosis following 5-FU exposure. Mechanistically, this was further associated with increased p53 transcriptional activation of p21 and PUMA. In addition, ERK5 inhibition increased the response of HCT116 p53+/+ cells to 5-FU, but failed to sensitize HCT116 p53−/− cells to the cytotoxic effects of this chemotherapeutic agent, suggesting a p53-dependent axis mediating 5-FU sensitization. Finally, ERK5 inhibition using XMD8-92 was shown to increase the antitumor effects of 5-FU in a murine subcutaneous xenograft model, enhancing apoptosis while markedly reducing tumor growth. Collectively, our results suggest that ERK5-targeted in hibition provides a promising therapeutic approach to overcome resistance to 5-FU-based chemotherapy and improve colon cancer treatment. PMID:27144434

The tactile motion aftereffect suggests an intensive code for speed in neurons sensitive to both speed and direction of motion

PubMed Central

Birznieks, I.; Vickery, R. M.; Holcombe, A. O.; Seizova-Cajic, T.

2016-01-01

Neurophysiological studies in primates have found that direction-sensitive neurons in the primary somatosensory cortex (SI) generally increase their response rate with increasing speed of object motion across the skin and show little evidence of speed tuning. We employed psychophysics to determine whether human perception of motion direction could be explained by features of such neurons and whether evidence can be found for a speed-tuned process. After adaptation to motion across the skin, a subsequently presented dynamic test stimulus yields an impression of motion in the opposite direction. We measured the strength of this tactile motion aftereffect (tMAE) induced with different combinations of adapting and test speeds. Distal-to-proximal or proximal-to-distal adapting motion was applied to participants' index fingers using a tactile array, after which participants reported the perceived direction of a bidirectional test stimulus. An intensive code for speed, like that observed in SI neurons, predicts greater adaptation (and a stronger tMAE) the faster the adapting speed, regardless of the test speed. In contrast, speed tuning of direction-sensitive neurons predicts the greatest tMAE when the adapting and test stimuli have matching speeds. We found that the strength of the tMAE increased monotonically with adapting speed, regardless of the test speed, showing no evidence of speed tuning. Our data are consistent with neurophysiological findings that suggest an intensive code for speed along the motion processing pathways comprising neurons sensitive both to speed and direction of motion. PMID:26823511

Cosmic distribution of highly ionized metals and their physical conditions in the EAGLE simulations

NASA Astrophysics Data System (ADS)

Rahmati, Alireza; Schaye, Joop; Crain, Robert A.; Oppenheimer, Benjamin D.; Schaller, Matthieu; Theuns, Tom

2016-06-01

We study the distribution and evolution of highly ionized intergalactic metals in the Evolution and Assembly of Galaxies and their Environment (EAGLE) cosmological, hydrodynamical simulations. EAGLE has been shown to reproduce a wide range of galaxy properties while its subgrid feedback was calibrated without considering gas properties. We compare the predictions for the column density distribution functions (CDDFs) and cosmic densities of Si IV, C IV, N V, O VI and Ne VIII absorbers with observations at redshift z = 0 to ˜6 and find reasonable agreement, although there are some differences. We show that the typical physical densities of the absorbing gas increase with column density and redshift, but decrease with the ionization energy of the absorbing ion. The typical metallicity increases with both column density and time. The fraction of collisionally ionized metal absorbers increases with time and ionization energy. While our results show little sensitivity to the presence or absence of AGN feedback, increasing/decreasing the efficiency of stellar feedback by a factor of 2 substantially decreases/increases the CDDFs and the cosmic densities of the metal ions. We show that the impact of the efficiency of stellar feedback on the CDDFs and cosmic densities is largely due to its effect on the metal production rate. However, the temperatures of the metal absorbers, particularly those of strong O VI, are directly sensitive to the strength of the feedback.

Auditory cortical neurons are sensitive to static and continuously changing interaural phase cues.

PubMed

Reale, R A; Brugge, J F

1990-10-01

1. The interaural-phase-difference (IPD) sensitivity of single neurons in the primary auditory (AI) cortex of the anesthetized cat was studied at stimulus frequencies ranging from 120 to 2,500 Hz. Best frequencies of the 43 AI cells sensitive to IPD ranged from 190 to 2,400 Hz. 2. A static IPD was produced when a pair of low-frequency tone bursts, differing from one another only in starting phase, were presented dichotically. The resulting IPD-sensitivity curves, which plot the number of discharges evoked by the binaural signal as a function of IPD, were deeply modulated circular functions. IPD functions were analyzed for their mean vector length (r) and mean interaural phase (phi). Phase sensitivity was relatively independent of best frequency (BF) but highly dependent on stimulus frequency. Regardless of BF or stimulus frequency within the excitatory response area the majority of cells fired maximally when the ipsilateral tone lagged the contralateral signal and fired least when this interaural-phase relationship was reversed. 3. Sensitivity to continuously changing IPD was studied by delivering to the two ears 3-s tones that differed slightly in frequency, resulting in a binaural beat. Approximately 26% of the cells that showed a sensitivity to static changes in IPD also showed a sensitivity to dynamically changing IPD created by this binaural tonal combination. The discharges were highly periodic and tightly synchronized to a particular phase of the binaural beat cycle. High synchrony can be attributed to the fact that cortical neurons typically respond to an excitatory stimulus with but a single spike that is often precisely timed to stimulus onset. A period histogram, binned on the binaural beat frequency (fb), produced an equivalent IPD-sensitivity function for dynamically changing interaural phase. For neurons sensitive to both static and continuously changing interaural phase there was good correspondence between their static (phi s) and dynamic (phi d) mean interaural phases. 4. All cells responding to a dynamically changing stimulus exhibited a linear relationship between mean interaural phase and beat frequency. Most cells responded equally well to binaural beats regardless of the initial direction of phase change. For a fixed duration stimulus, and at relatively low fb, the number of spikes evoked increased with increasing fb, reflecting the increasing number of effective stimulus cycles. At higher fb, AI neurons were unable to follow the rate at which the most effective phase repeated itself during the 3 s of stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)

Stress-dependent elastic properties of shales—laboratory experiments at seismic and ultrasonic frequencies

NASA Astrophysics Data System (ADS)

Szewczyk, Dawid; Bauer, Andreas; Holt, Rune M.

2018-01-01

Knowledge about the stress sensitivity of elastic properties and velocities of shales is important for the interpretation of seismic time-lapse data taken as part of reservoir and caprock surveillance of both unconventional and conventional oil and gas fields (e.g. during 4-D monitoring of CO2 storage). Rock physics models are often developed based on laboratory measurements at ultrasonic frequencies. However, as shown previously, shales exhibit large seismic dispersion, and it is possible that stress sensitivities of velocities are also frequency dependent. In this work, we report on a series of seismic and ultrasonic laboratory tests in which the stress sensitivity of elastic properties of Mancos shale and Pierre shale I were investigated. The shales were tested at different water saturations. Dynamic rock engineering parameters and elastic wave velocities were examined on core plugs exposed to isotropic loading. Experiments were carried out in an apparatus allowing for static-compaction and dynamic measurements at seismic and ultrasonic frequencies within single test. For both shale types, we present and discuss experimental results that demonstrate dispersion and stress sensitivity of the rock stiffness, as well as P- and S-wave velocities, and stiffness anisotropy. Our experimental results show that the stress-sensitivity of shales is different at seismic and ultrasonic frequencies, which can be linked with simultaneously occurring changes in the dispersion with applied stress. Measured stress sensitivity of elastic properties for relatively dry samples was higher at seismic frequencies however, the increasing saturation of shales decreases the difference between seismic and ultrasonic stress-sensitivities, and for moist samples stress-sensitivity is higher at ultrasonic frequencies. Simultaneously, the increased saturation highly increases the dispersion in shales. We have also found that the stress-sensitivity is highly anisotropic in both shales and that in some of the cases higher stress-sensitivity of elastic properties can be seen in the direction parallel to the bedding plane.

Spectroscopic and fiber optic ethanol sensing properties Gd doped ZnO nanoparticles.

PubMed

Noel, J L; Udayabhaskar, R; Renganathan, B; Muthu Mariappan, S; Sastikumar, D; Karthikeyan, B

2014-11-11

We report the structural, optical and gas sensing properties of prepared pure and Gd doped ZnO nanoparticles through solgel method at moderate temperature. Structural studies are carried out by X-ray diffraction method confirms hexagonal wurtzite structure and doping induced changes in lattice parameters is observed. Optical absorption spectral studies shows red shift in the absorption peak corresponds to band-gap from 3.42 eV to 3.05 eV and broad absorption in the visible range after Gd doping is observed. Scanning electron microscopic studies shows increase in particle size where the particle diameters increase from few nm to micrometers after Gd doping. The clad modified ethanol fiber-optic sensor studies for ethanol sensing exhibits best sensitivity for the 3% Gd doped ZnO nanoparticles and the sensitivity get lowered incase of higher percentage of Gd doped ZnO sample. Copyright © 2014 Elsevier B.V. All rights reserved.

Warping Armchair Graphene Nanoribbon Curvature Effect on Sensing Properties: A Computational Study

NASA Astrophysics Data System (ADS)

Sakina, S. H.; Johari, Zaharah; Auzar, Zuriana; Alias, N. Ezaila; Mohamad, Azam; Zakaria, N. Aini

2018-02-01

The aim of this paper is to investigate the interaction between gas molecules and warped armchair graphene nanoribbons (AGNRs) using Extended-Huckel Theory. There are two types of warping known as inward and upward. The sensing properties including binding energy, charge transfer and sensitivity were examined for both warped AGNR cases for 3m+1 configuration and were compared with previous work. Through simulation, it was found that a substantial increase in binding energy by more than 50% was achieved when warped at a higher angle. It is also showed that there was a significant difference in sensitivity for both warping cases when reacting with O2 and NH3 molecules. Interestingly, the ability of the inward warped in sensing O2 and NH3 considerably increases upon warping angle. By applying back gate bias, this shows that current conductivity of the inward warped is twice as high as the upward warped AGNR.

Improve the refractive index sensitivity of coaxial-cable type gold nanostructure: the effect of dielectric polarization from the separate layer

NASA Astrophysics Data System (ADS)

Zhu, Jian; Li, Jian-Jun; Zhao, Jun-Wu

2013-06-01

The separate layer refractive index sensitivity of a coaxial-cable type three-layered gold nanotube has been studied. Theoretical calculation results based on quasi-static model show that the coaxial-cable type gold nanostructure has higher refractive index sensitivity than that of single-layered gold nanotube. This sensitivity could be improved by increasing the inner wire radius or decreasing the total radius of the tube, and the maximum sensitivity may exceed 1,000 nm per refractive index unit. The physical origin was also investigated based on the coupling of the dielectric media induced polarizations and the local electric fields in separate layer and outer surrounding. These separate layer refractive index sensing properties of coaxial-cable type gold nanostructure present well potential for plasmonic biosensing applications.

Co-sensitization of natural dyes for improved efficiency in dye-sensitized solar cell application

NASA Astrophysics Data System (ADS)

Kumar, K. Ashok; Subalakshmi, K.; Senthilselvan, J.

2016-05-01

In this paper, a new approach of co-sensitized DSSC based on natural dyes is investigated to explore the possible way to improve the power conversion efficiency. To realize this purpose 10 DSSC devices were fabricated using mono-sensitization and co-sensitization of ethanolic extracts of natural dye sensitizers obtained from Cactus fruit, Jambolana fruit, Curcumin and Bermuda grass. The optical absorption spectrum of the mono and hybrid dye extracts were studied by UV-Visible absorption spectrum. It shows the characteristic absorption peaks in visible region corresponds to the presence of natural pigments of anthocyanin, betacyanin and chlorophylls. Absorption spectrum of hybrid dyes reveals a wide absorption band in visible region with improved extinction co-efficient and it is favorable for increased light harvesting nature. The power conversion efficiency of DSSC devices were calculated using J-V curve and the maximum efficiency achieved in the present work is noted to be ~0.61% for Cactus-Bermuda co-sensitized DSSC.

Alpha, Beta and Gamma Diversity Differ in Response to Precipitation in the Inner Mongolia Grassland

PubMed Central

Zhang, Qing; Hou, Xiangyang; Li, Frank Yonghong; Niu, Jianming; Zhou, Yanlin; Ding, Yong; Zhao, Liqing; Li, Xin; Ma, Wenjing; Kang, Sarula

2014-01-01

Understanding the distribution pattern and maintenance mechanism of species diversity along environmental gradients is essential for developing biodiversity conservation strategies under environmental change. We have surveyed the species diversity at 192 vegetation sites across different steppe zones in Inner Mongolia, China. We analysed the total species diversity (γ diversity) and its composition (α diversity and β diversity) of different steppe types, and their changes along a precipitation gradient. Our results showed that (i) β diversity contributed more than α diversity to the total (γ) diversity in the Inner Mongolia grassland; the contribution of β diversity increased with precipitation, thus the species-rich (meadow steppe) grassland had greater contribution of β diversity than species-poor (desert steppe) grassland. (ii) All α, β and γ species diversity increased significantly (P<0.05) with precipitation, but their sensitivity to precipitation (diversity change per mm precipitation increase) was different between the steppe types. The sensitivity of α diversity of different steppe community types was negatively (P<0.05) correlated with mean annual precipitation, whereas the sensitivity of β and γ diversity showed no trend along the precipitation gradient (P>0.10). (iii) The α diversity increased logarithmically, while β diversity increased exponentially, with γ diversity. Our results suggest that for local species diversity patterns, the site species pool is more important in lower precipitation areas, while local ecological processes are more important in high precipitation areas. In addition, for β diversity maintenance niche processes and diffusion processes are more important in low and high precipitation areas, respectively. Our results imply that a policy of “multiple small reserves” is better than one of a “single large reserve” for conserving species diversity of a steppe ecosystem, and indicate an urgent need to develop management strategies for climate-sensitive desert steppe ecosystem. PMID:24675900

Large scale afforestation projects mitigate degradation and increase the stability of the karst ecosystems in southwest China

NASA Astrophysics Data System (ADS)

Yue, Y.; Tong, X.; Wang, K.; Fensholt, R.; Brandt, M.

2017-12-01

With the aim to combat desertification and improve the ecological environment, mega-engineering afforestation projects have been launched in the karst regions of southwest China around the turn of the new millennium. A positive impact of these projects on vegetation cover has been shown, however, it remains unclear if conservation efforts have been able to effectively restore ecosystem properties and reduce the sensitivity of the karst ecosystem to climate variations at large scales. Here we use passive microwave and optical satellite time series data combined with the ecosystem model LPJ-GUESS and show widespread increase in vegetation cover with a clear demarcation at the Chinese national border contrasting the conditions of neighboring countries. We apply a breakpoint detection to identify permanent changes in vegetation time series and assess the vegetation's sensitivity against climate before and after the breakpoints. A majority (74%) of the breakpoints were detected between 2001 and 2004 and are remarkably in line with the implementation and spatial extent of the Grain to Green project. We stratify the counties of the study area into four groups according to the extent of Grain to Green conservation areas and find distinct differences between the groups. Vegetation trends are similar prior to afforestation activities (1982-2000), but clearly diverge at a later stage, following the spatial extent of conservation areas. Moreover, vegetation cover dynamics were increasingly decoupled from climatic influence in areas of high conservation efforts. Whereas both vegetation resilience and resistance were considerably improved in areas with large conservation efforts thereby showing an increase in ecosystem stability, ongoing degradation and an amplified sensitivity to climate variability was found in areas with limited project implementation. Our study concludes that large scale conservation projects can regionally contribute to a greening Earth and are able to mitigate desertification by increasing the vegetation cover and reducing the ecosystem sensitivity to climate change, however, degradation remains a serious issue in the karst ecosystem of southwest China.

Magneto-optic evaluation of antiferromagnetic α-Fe2O3 nanoparticles coated on a quartz substrate

NASA Astrophysics Data System (ADS)

Balasubramanian, Srinath; Panmand, Rajendra; Kumar, Ganapathy; Mahajan, Satish M.; Kale, Bharat B.

2016-03-01

This paper presents a prima facie study of the magneto-optic response of antiferromagnetic α-Fe2O3 nanoparticles coated on a quartz substrate investigated by MOKE. The concentrations of the iron oxide nanoparticles in the films were varied from 8.6% to 21.5% and showed a linear increase in film thicknesses. As the concentration of the iron oxide nanoparticles were increased, the samples changed from a net-like morphology to a crystalline morphology. Magnetization reversals in the lower concentration samples were asymmetric with the reversals for the ascending and descending branch of the hysteresis loop occurring on the same side. The asymmetry in the magnetization reversal was attributed to the angle between the antiferromagnetic easy axis and the external magnetic field. With increase in concentration, an improvement in the magneto-optic response was observed with the magnetization reversal occurring via coherent rotation for both ascending and descending branches of the hysteresis loop. The changes in the magneto-optic behavior for the samples with higher concentrations is attributed to the strong exchange interactions and changes in the shape of the nanoparticles. Sensitivity studies performed on the samples showed an increased magneto-optic sensitivity to changes in magnetic field for samples of higher concentration. The high sensitivity of these samples could be exploited in magneto-optic sensors. Nanoparticles on a quartz substrate could find applications in bio-medicine due to their bio-compatibility.

Exacerbation of allergic inflammation in mice exposed to diesel exhaust particles prior to viral infection

PubMed Central

Jaspers, Ilona; Sheridan, Patricia A; Zhang, Wenli; Brighton, Luisa E; Chason, Kelly D; Hua, Xiaoyang; Tilley, Stephen L

2009-01-01

Background Viral infections and exposure to oxidant air pollutants are two of the most important inducers of asthma exacerbation. Our previous studies have demonstrated that exposure to diesel exhaust increases the susceptibility to influenza virus infections both in epithelial cells in vitro and in mice in vivo. Therefore, we examined whether in the setting of allergic asthma, exposure to oxidant air pollutants enhances the susceptibility to respiratory virus infections, which in turn leads to increased virus-induced exacerbation of asthma. Ovalbumin-sensitized (OVA) male C57BL/6 mice were instilled with diesel exhaust particles (DEP) or saline and 24 hours later infected with influenza A/PR/8. Animals were sacrificed 24 hours post-infection and analyzed for markers of lung injury, allergic inflammation, and pro-inflammatory cytokine production. Results Exposure to DEP or infection with influenza alone had no significant effects on markers of injury or allergic inflammation. However, OVA-sensitized mice that were exposed to DEP and subsequently infected with influenza showed increased levels of eosinophils in lung lavage and tissue. In addition Th2-type cytokines, such as IL-4 and IL-13, and markers of eosinophil chemotaxis, such as CCL11 and CCR3, were increased in OVA-sensitized mice exposed to DEP prior to infection with influenza. These mice also showed increased levels of IL-1α, but not IL-10, RANTES, and MCP-1 in lung homogenates. Conclusion These data suggest that in the setting of allergic asthma, exposure to diesel exhaust could enhance virus-induced exacerbation of allergic inflammation. PMID:19682371

Functional analysis of inappropriate social interactions in students with Asperger's syndrome.

PubMed

Roantree, Christina F; Kennedy, Craig H

2012-01-01

We analyzed the inappropriate social interactions of 3 students with Asperger's syndrome whose behavior was maintained by social positive reinforcement. We tested whether inappropriate social behavior was sensitive to social positive reinforcement contingencies and whether such contingencies could be reversed to increase the probability of socially appropriate responding. Our results show that social positive reinforcers can be identified for inappropriate social interactions and that appropriate social behaviors can be sensitive to reinforcement contingency reversals.

Contrasting nutrient-disease relationships: Potassium gradients in barley leaves have opposite effects on two fungal pathogens with different sensitivities to jasmonic acid.

PubMed

Davis, Jayne L; Armengaud, Patrick; Larson, Tony R; Graham, Ian A; White, Philip J; Newton, Adrian C; Amtmann, Anna

2018-05-31

Understanding the interactions between mineral nutrition and disease is essential for crop management. Our previous studies with Arabidopsis thaliana demonstrated that potassium (K) deprivation induced the biosynthesis of jasmonate (JA) and increased the plant's resistance to herbivorous insects. Here we addressed the question how tissue K affects the development of fungal pathogens and whether sensitivity of the pathogens to JA could play a role for the K-disease relationship in barley (Hordeum vulgare cv. Optic). We report that K-deprived barley plants showed increased leaf concentrations of JA and other oxylipins. Furthermore, a natural tip-to base K-concentrations gradient within leaves of K-sufficient plants was quantitatively mirrored by the transcript levels of JA-responsive genes. The local leaf tissue K concentrations affected the development of two economically important fungi in opposite ways, showing a positive correlation with powdery mildew (Blumeria graminis) and a negative correlation with leaf scald (Rhynchosporium commune) disease symptoms. B. graminis induced a JA-response in the plant and was sensitive to methyl-JA treatment while R. commune initiated no JA-response and was JA-insensitive. Our study challenges the view that high K generally improves plant health and suggests that JA-sensitivity of pathogens could be an important factor determining the exact K-disease relationship. This article is protected by copyright. All rights reserved.

Nanotip analysis for dielectrophoretic concentration of nanosized viral particles.

PubMed

Yeo, Woon-Hong; Lee, Hyun-Boo; Kim, Jong-Hoon; Lee, Kyong-Hoon; Chung, Jae-Hyun

2013-05-10

Rapid and sensitive detection of low-abundance viral particles is strongly demanded in health care, environmental control, military defense, and homeland security. Current detection methods, however, lack either assay speed or sensitivity, mainly due to the nanosized viral particles. In this paper, we compare a dendritic, multi-terminal nanotip ('dendritic nanotip') with a single terminal nanotip ('single nanotip') for dielectrophoretic (DEP) concentration of viral particles. The numerical computation studies the concentration efficiency of viral particles ranging from 25 to 100 nm in radius for both nanotips. With DEP and Brownian motion considered, when the particle radius decreases by two times, the concentration time for both nanotips increases by 4-5 times. In the computational study, a dendritic nanotip shows about 1.5 times faster concentration than a single nanotip for the viral particles because the dendritic structure increases the DEP-effective area to overcome the Brownian motion. For the qualitative support of the numerical results, the comparison experiment of a dendritic nanotip and a single nanotip is conducted. Under 1 min of concentration time, a dendritic nanotip shows a higher sensitivity than a single nanotip. When the concentration time is 5 min, the sensitivity of a dendritic nanotip for T7 phage is 10(4) particles ml(-1). The dendritic nanotip-based concentrator has the potential for rapid identification of viral particles.

Ecotoxicity of wastes in avoidance tests with Enchytraeus albidus, Enchytraeus crypticus and Eisenia fetida (Oligochaeta).

PubMed

Kobeticová, Klára; Hofman, Jakub; Holoubek, Ivan

2010-04-01

Contact bioassays are important for testing the ecotoxicity of solid materials. However, survival and reproduction tests are often not practical due to their duration which may last for several weeks. Avoidance tests with soil invertebrates may offer an alternative or extension to the classic test batteries due to their short duration (days rather than weeks) and due to a sensitive sub-acute endpoint (behavior). (a) to evaluate the effects of three solid industrial wastes (incineration ash, contaminated wood chips and contaminated soil) on three Oligochaeta species (enchytraeids Enchytraeusalbidus, Enchytraeus crypticus and earthworm Eisenia fetida) in avoidance tests; (b) to compare the sensitivity among the species and to compare results of avoidance test to reproduction tests; (c) to elucidate if measuring the weight in the earthworm avoidance test could be reasonable additional endpoint. Avoidance mostly increased with the increasing percent of waste in the mixture showing a dose-response curve. E. fetida was the most sensitive species and E. crypticus the least one. An additional endpoint, (changes in weight after two-day exposure) was not found to be more sensitive than avoidance reaction, but it confirmed that earthworms staying in the highest concentrations of the waste mixture were affected showing apparent weight reduction. Our results indicate that avoidance tests with earthworms and enchytraeids are feasible for waste testing. Copyright 2009 Elsevier Ltd. All rights reserved.

Nanotip analysis for dielectrophoretic concentration of nanosized viral particles

NASA Astrophysics Data System (ADS)

Yeo, Woon-Hong; Lee, Hyun-Boo; Kim, Jong-Hoon; Lee, Kyong-Hoon; Chung, Jae-Hyun

2013-05-01

Rapid and sensitive detection of low-abundance viral particles is strongly demanded in health care, environmental control, military defense, and homeland security. Current detection methods, however, lack either assay speed or sensitivity, mainly due to the nanosized viral particles. In this paper, we compare a dendritic, multi-terminal nanotip (‘dendritic nanotip’) with a single terminal nanotip (‘single nanotip’) for dielectrophoretic (DEP) concentration of viral particles. The numerical computation studies the concentration efficiency of viral particles ranging from 25 to 100 nm in radius for both nanotips. With DEP and Brownian motion considered, when the particle radius decreases by two times, the concentration time for both nanotips increases by 4-5 times. In the computational study, a dendritic nanotip shows about 1.5 times faster concentration than a single nanotip for the viral particles because the dendritic structure increases the DEP-effective area to overcome the Brownian motion. For the qualitative support of the numerical results, the comparison experiment of a dendritic nanotip and a single nanotip is conducted. Under 1 min of concentration time, a dendritic nanotip shows a higher sensitivity than a single nanotip. When the concentration time is 5 min, the sensitivity of a dendritic nanotip for T7 phage is 104 particles ml-1. The dendritic nanotip-based concentrator has the potential for rapid identification of viral particles.

Correlation of Radiological and Endoscopic Findings in Patients Presenting with Dysphagia.

PubMed

Sachdeva, Kavita; Kaul, Vineet

2017-03-01

Dysphagia is a common symptom with diverse etiology in otolaryngology. In the present study clinicopathological, radiological and endoscopic evaluation of patients was done in a tertiary care hospital in patients presenting with dysphagia. A prospective nonrandomized observational study was carried out on total of 80 cases having dysphagia during March 2015 to August 2016. In the present study, out of 80 patients, youngest case was a three years old child while oldest case was an 85 years old female. The mean age was 48.3 ± 20.3 years. The majority of cases were in age group 41-59 years (35%). Male to female ratio was 2.33:1. The mean duration of illness was 15.44 weeks. 15% of patients had absolute dysphagia. For detecting the lesion, Barium swallow study (BSS) showed a total sensitivity of 49.05% (n = 53), Computerised Tomography (CT) showed a total sensitivity of 85.70% (n = 49), plain skiagram neck & chest showed a total sensitivity of 88.88% (n = 9) and endoscopy was the most sensitive test overall as it showed a total sensitivity of 98.75% (n = 80). No complications were reported with either rigid or flexible endoscopy. Dysphagia is a common presenting complaint in otolaryngology with cases coming directly or being referred from other specialities. Males are more commonly affected than females and incidence of malignancy increases with age. Endoscopy can become the first screening test in dysphagia due to its high sensitivity and low risk of complications, with radiological tests being done in an adjunct manner.

Abalation of ghrelin receptor reduces adiposity and improves insulin sensitivity during aging by regulating fat metabolism in white and brown adipose tissues

USDA-ARS?s Scientific Manuscript database

Aging is associated with increased adiposity in white adipose tissues and impaired thermogenesis in brown adipose tissues; both contribute to increased incidences of obesity and type 2 diabetes. Ghrelin is the only known circulating orexigenic hormone that promotes adiposity. In this study, we show ...

On the Piezoelectric Detection of Guided Ultrasonic Waves

PubMed Central

2017-01-01

In order to quantify the wave motion of guided ultrasonic waves, the characteristics of piezoelectric detectors, or ultrasonic transducers and acoustic emission sensors, have been evaluated systematically. Such guided waves are widely used in structural health monitoring and nondestructive evaluation, but methods of calibrating piezoelectric detectors have been inadequate. This study relied on laser interferometry for the base displacement measurement of bar waves, from which eight different guided wave test set-ups are developed with known wave motion using piezoelectric transmitters. Both plates and bars of 12.7 and 6.4 mm thickness were used as wave propagation media. The upper frequency limit was 2 MHz. Output of guided wave detectors were obtained on the test set-ups and their receiving sensitivities were characterized and averaged. While each sensitivity spectrum was noisy for a detector, the averaged spectrum showed a good convergence to a unique receiving sensitivity. Twelve detectors were evaluated and their sensitivity spectra determined in absolute units. Generally, these showed rapidly dropping sensitivity with increasing frequency due to waveform cancellation on their sensing areas. This effect contributed to vastly different sensitivities to guided wave and to normally incident wave for each one of the 12 detectors tested. Various other effects are discussed and recommendations on methods of implementing the approach developed are provided. PMID:29156579

Upregulation of T-type Ca2+ channels in long-term diabetes determines increased excitability of a specific type of capsaicin-insensitive DRG neurons.

PubMed

Duzhyy, Dmytro E; Viatchenko-Karpinski, Viacheslav Y; Khomula, Eugen V; Voitenko, Nana V; Belan, Pavel V

2015-05-20

Previous studies have shown that increased excitability of capsaicin-sensitive DRG neurons and thermal hyperalgesia in rats with short-term (2-4 weeks) streptozotocin-induced diabetes is mediated by upregulation of T-type Ca(2+) current. In longer-term diabetes (after the 8th week) thermal hyperalgesia is changed to hypoalgesia that is accompanied by downregulation of T-type current in capsaicin-sensitive small-sized nociceptors. At the same time pain symptoms of diabetic neuropathy other than thermal persist in STZ-diabetic animals and patients during progression of diabetes into later stages suggesting that other types of DRG neurons may be sensitized and contribute to pain. In this study, we examined functional expression of T-type Ca(2+) channels in capsaicin-insensitive DRG neurons and excitability of these neurons in longer-term diabetic rats and in thermally hypoalgesic diabetic rats. Here we have demonstrated that in STZ-diabetes T-type current was upregulated in capsaicin-insensitive low-pH-sensitive small-sized nociceptive DRG neurons of longer-term diabetic rats and thermally hypoalgesic diabetic rats. This upregulation was not accompanied by significant changes in biophysical properties of T-type channels suggesting that a density of functionally active channels was increased. Sensitivity of T-type current to amiloride (1 mM) and low concentration of Ni(2+) (50 μM) implicates prevalence of Cav3.2 subtype of T-type channels in the capsaicin-insensitive low-pH-sensitive neurons of both naïve and diabetic rats. The upregulation of T-type channels resulted in the increased neuronal excitability of these nociceptive neurons revealed by a lower threshold for action potential initiation, prominent afterdepolarizing potentials and burst firing. Sodium current was not significantly changed in these neurons during long-term diabetes and could not contribute to the diabetes-induced increase of neuronal excitability. Capsaicin-insensitive low-pH-sensitive type of DRG neurons shows diabetes-induced upregulation of Cav3.2 subtype of T-type channels. This upregulation results in the increased excitability of these neurons and may contribute to nonthermal nociception at a later-stage diabetes.

Improvement of insulin sensitivity in response to exercise training in type 2 diabetes mellitus is associated with vascular endothelial growth factor A expression.

PubMed

Wagner, Henrik; Fischer, Helene; Degerblad, Marie; Alvarsson, Michael; Gustafsson, Thomas

2016-09-01

Insulin sensitivity changes in response to exercise training demonstrate a large variation. Vascular endothelial growth factor A could promote increased insulin sensitivity through angiogenesis. We investigated associations between changes in expression of key genes and insulin sensitivity, aerobic capacity and glycaemic control following exercise training in diabetes mellitus type 2. Subjects with diabetes mellitus type 2 underwent 12 weeks of structured exercise. Euglycaemic clamp, exercise test and HbA1c were performed. Muscle biopsies were obtained for mRNA expression. A total of 16 subjects completed the study. Change in vascular endothelial growth factor A expression was positively associated with an increase in insulin sensitivity (p = 0.004) and with a decrease in HbA1c (p = 0.034). Vascular endothelial growth factor A receptor-1 expression showed similar associations. The variation in physical adaptation to exercise training in diabetes mellitus type 2 was associated with changes in expression of vascular endothelial growth factor A in muscle. This difference in induced gene expression could contribute to the variation in exercise training effects on insulin sensitivity. Measures of capillary blood flow need to be assessed in future studies. © The Author(s) 2016.

Co-sensitization of ZnO by CdS quantum dots in natural dye-sensitized solar cells with polymeric electrolytes to improve the cell stability

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

Junhom, W.; Magaraphan, R.

2015-05-22

The CdS quantum dots (QDs) were deposited on ZnO layer by chemical bath deposition method to absorb light in the shorter wavelength region and used as photoanode in the dye sensitized solar cell (DSSCs) with natural dye extracted from Noni leaves. Microstructures of CdS-ZnO from various dipping time were characterized by XRD, FE-SEM and EDX. The results showed that the CdS is hexagonal structure and the amount of CdS increases when the dipping time increases. The maximal conversion efficiency of 0.292% was achieved by the DSSCs based on CdS QDs-sensitized ZnO film obtained from 9 min-dipping time. Furthermore, the stability ofmore » DSSCs was improved by using polymeric electrolyte. Poly (acrylic acid) (PAA) and Polyacrylamide (PAM) were introduced to CdS QDs-sensitized ZnO film from 9 min-dipping time. Each polymeric electrolyte was prepared by swelling from 0.1-2.0 %w in H2O. The maximal conversion efficiency of 0.207% was achieved for DSSCs based on CdS QDs-sensitized ZnO film with PAM 1.0% and the conversion efficiency was decreased 25% when it was left for1 hr.« less

Co-sensitization of ZnO by CdS quantum dots in natural dye-sensitized solar cells with polymeric electrolytes to improve the cell stability

NASA Astrophysics Data System (ADS)

Junhom, W.; Magaraphan, R.

2015-05-01

The CdS quantum dots (QDs) were deposited on ZnO layer by chemical bath deposition method to absorb light in the shorter wavelength region and used as photoanode in the dye sensitized solar cell (DSSCs) with natural dye extracted from Noni leaves. Microstructures of CdS-ZnO from various dipping time were characterized by XRD, FE-SEM and EDX. The results showed that the CdS is hexagonal structure and the amount of CdS increases when the dipping time increases. The maximal conversion efficiency of 0.292% was achieved by the DSSCs based on CdS QDs-sensitized ZnO film obtained from 9 min-dipping time. Furthermore, the stability of DSSCs was improved by using polymeric electrolyte. Poly (acrylic acid) (PAA) and Polyacrylamide (PAM) were introduced to CdS QDs-sensitized ZnO film from 9 min-dipping time. Each polymeric electrolyte was prepared by swelling from 0.1-2.0 %w in H2O. The maximal conversion efficiency of 0.207% was achieved for DSSCs based on CdS QDs-sensitized ZnO film with PAM 1.0% and the conversion efficiency was decreased 25% when it was left for1 hr.

Evaluation of autofluorescence and toluidine blue in the differentiation of oral dysplastic and neoplastic lesions from non dysplastic and neoplastic lesions: a cross-sectional study

NASA Astrophysics Data System (ADS)

Petruzzi, Massimo; Lucchese, Alberta; Nardi, Gianna Maria; Lauritano, Dorina; Favia, Gianfranco; Serpico, Rosario; Grassi, Felice Roberto

2014-07-01

The objective was to compare toluidine blue (TB) and autofluorescence (AF) for the detection of oral dysplasia and squamous cell carcinoma (OSCC) in clinically suspicious lesions according to conventional examination. Fifty-six clinically suspicious lesions were subjected to AF and TB examination. Data were compared using two different scenarios: in the first, mild dysplasia was considered as positive, while in the second, it was considered as negative. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), accuracy, and concordance were calculated. AF sensitivity and specificity were 70.0 and 57.7%, respectively, while TB showed a sensitivity of 80% and a specificity of 61.5%. The sensitivity increased in the second scenario in both AF (76.5%) and TB (88.2%). The specificity decreased in AF and TB, showing the same value (51.3%). PPV was higher in TB than in AF (70.6 versus 65.6%) and similarly for NPV (72.7 versus 62.5%). In the second scenario, TB PPV was 44.1% and NPV was 90.9% AF PPV was 40.6% and NPV was 83.3%. TB showed greater accuracy than AF in the first scenario (62.5 versus 58.9%). AF and TB are both sensitive but not specific in OSCC and dysplasia diagnosis.

[Predicating the sensibility of patients with multiple myeloma to glucocorticoid by cochaperone P23].

PubMed

Xue, Jun; Xie, Xiao-Jing; Cao, Peng

2012-02-01

This study was aimed to investigate the sensitive index for predicting the sensitivity of patients with multiple myeloma (MM) to glucocorticoid (GC). MM1.S, MM1.R cell lines and 10 MM patients sensitive or non-sensitive to GC were enrolled in this study. The expression of heat shock protein 90 (HSP90) and P23 in peripheral blood mononuclear cells (PBMNC) of MM patients was detected by Western blot, and its relation with GC resistance was explored. The results showed that there were no differences in HSP90, GR and IκB-α expressions among MM1.S, MM1.R, PBMNC of normal persons and MM patients, while there was apparent difference in P23; along with increasing of dexamethasone dose, the survival rate of MM1.S decreased, but that of MM1.R did not change so obviously. Among 7 cases with P23 low expression, combination treatment scheme with GC was effective in 6 cases (86%), uneffective in 1 cases (14%); while among 3 cases with P23 high expression, 1 cases (33%) showed effective to combination treatment with GC, 2 cases (67%) showed uneffective (P < 0.05). It is concluded that the P23 expression may predict the sensitivity of MM patients to GC and may be used as index for guiding clinical treatment.

Probiotic supplementation for the first 6 months of life fails to reduce the risk of atopic dermatitis and increases the risk of allergen sensitization in high-risk children: a randomized controlled trial.

PubMed

Taylor, Angie L; Dunstan, Janet A; Prescott, Susan L

2007-01-01

Despite preliminary evidence, the role of probiotics in allergy prevention is unclear. To determine whether early probiotic supplementation prevents allergic disease in high-risk infants. Newborns of women with allergy (n = 231) received either Lactobacillus acidophilus (LAVRI-A1) or placebo daily for the first 6 months of life. Children were assessed for atopic dermatitis (AD) and other symptoms at 6 and 12 months and had allergen skin prick tests (SPT) at 12 months of age. A total of 178 infants completed the supplementation period. Those in the probiotic group showed significantly higher rates of Lactobacillus colonization (P = .039). At 6 months, AD rates were similar in the probiotic (n = 23/89; 25.8%) and placebo (n = 20/88; 22.7%) groups (P = .629). There was also no difference at 12 months, although the proportion of children with SPT+AD was significantly higher in the probiotic group (P = .045). At 12 months, the rate of sensitization was significantly higher in the probiotic group (P = .030). The presence of culturable Lactobacilli or Bifidobacterium in stools in the first month of life was not associated with the risk of subsequent sensitization or disease; however, the presence of Lactobacillus at 6 months of age was associated with increased risk of subsequent cow's milk sensitization (P = .012). Early probiotic supplementation with L acidophilus did not reduce the risk of AD in high-risk infants and was associated with increased allergen sensitization in infants receiving supplements. The long-term significance of the increased rate of sensitization needs to be investigated in further studies. These findings challenge the role of probiotics in allergy prevention.

Stratospheric water vapor feedback.

PubMed

Dessler, A E; Schoeberl, M R; Wang, T; Davis, S M; Rosenlof, K H

2013-11-05

We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric water vapor feedback. We estimate the strength of this feedback in a chemistry-climate model to be +0.3 W/(m(2)⋅K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause.

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

Schlecht, William; Li, King-Lun; Hu, Dehong

By examining the behavior of each Ca2+ -sensitizer on cTnC at different levels of reconstitution (cTnI-cTnC, full troponin, or full troponin in thin filament) the importance of these proteins on sensitizer efficacy was evaluated, lending insight into the mechanism of action behind each drug. A fluorescence based approach was used to monitor the opening and closing of cardiac troponin C's hydrophobic pocket in the presence and absence of four common Ca2+ -sensitizers: EMD 57033, levosimendan, bepridil and pimobendan. Ca2+ -titration experiments were employed to determine the effect on Ca2+- sensitivity and cooperativity of cTnC opening, while stopped flow experiments weremore » used to investigate the impact on cTnC relaxation kinetics. This study shows EMD 57033 is unable to sensitize cTnC to Ca2+, and likely requires the presence of myosin to illicit a response. Levosimendan, bepridil, and pimobendan were all able to increase the sensitivity of cTnC for Ca2+ to varying degrees; levosimendan and pimobendan reduced the rate of cTnC closing, while bepridil increased this rate. Additionally the same experiments were run on thin filament samples containing cTnT (T204E), a known Ca2+- blunting phosphorylation mimic. Levosimendan, bepridil, and pimobendan were found to elevate the Ca2+-sensitivity of cTnT(T204E) containing thin filaments to within range of the wild type thin filaments.« less

Ethylene regulates Apple (Malus x domestica) fruit softening through a dose x time-dependent mechanism and through differential sensitivities and dependencies of cell wall-modifying genes.

PubMed

Ireland, Hilary S; Gunaseelan, Kularajathevan; Muddumage, Ratnasiri; Tacken, Emma J; Putterill, Jo; Johnston, Jason W; Schaffer, Robert J

2014-05-01

In fleshy fruit species that have a strong requirement for ethylene to ripen, ethylene is synthesized autocatalytically, producing increasing concentrations as the fruits ripen. Apple fruit with the ACC OXIDASE 1 (ACO1) gene suppressed cannot produce ethylene autocatalytically at ripening. Using these apple lines, an ethylene sensitivity dependency model was previously proposed, with traits such as softening showing a high dependency for ethylene as well as low sensitivity. In this study, it is shown that the molecular control of fruit softening is a complex process, with different cell wall-related genes being independently regulated and exhibiting differential sensitivities to and dependencies on ethylene at the transcriptional level. This regulation is controlled through a dose × time mechanism, which results in a temporal transcriptional response that would allow for progressive cell wall disassembly and thus softening. This research builds on the sensitivity dependency model and shows that ethylene-dependent traits can progress over time to the same degree with lower levels of ethylene. This suggests that a developmental clock measuring cumulative ethylene controls the fruit ripening process.

Sensitivity of atmospheric aerosol scavenging to precipitation intensity and frequency in the context of global climate change

NASA Astrophysics Data System (ADS)

Hou, Pei; Wu, Shiliang; McCarty, Jessica L.; Gao, Yang

2018-06-01

Wet deposition driven by precipitation is an important sink for atmospheric aerosols and soluble gases. We investigate the sensitivity of atmospheric aerosol lifetimes to precipitation intensity and frequency in the context of global climate change. Our sensitivity model simulations, through some simplified perturbations to precipitation in the GEOS-Chem model, show that the removal efficiency and hence the atmospheric lifetime of aerosols have significantly higher sensitivities to precipitation frequencies than to precipitation intensities, indicating that the same amount of precipitation may lead to different removal efficiencies of atmospheric aerosols. Combining the long-term trends of precipitation patterns for various regions with the sensitivities of atmospheric aerosol lifetimes to various precipitation characteristics allows us to examine the potential impacts of precipitation changes on atmospheric aerosols. Analyses based on an observational dataset show that precipitation frequencies in some regions have decreased in the past 14 years, which might increase the atmospheric aerosol lifetimes in those regions. Similar analyses based on multiple reanalysis meteorological datasets indicate that the changes of precipitation intensity and frequency over the past 30 years can lead to perturbations in the atmospheric aerosol lifetimes by 10 % or higher at the regional scale.

The dorsal raphe modulates sensory responsiveness during arousal in zebrafish

PubMed Central

Yokogawa, Tohei; Hannan, Markus C.; Burgess, Harold A.

2012-01-01

During waking behavior animals adapt their state of arousal in response to environmental pressures. Sensory processing is regulated in aroused states and several lines of evidence imply that this is mediated at least partly by the serotonergic system. However there is little information directly showing that serotonergic function is required for state-dependent modulation of sensory processing. Here we find that zebrafish larvae can maintain a short-term state of arousal during which neurons in the dorsal raphe modulate sensory responsiveness to behaviorally relevant visual cues. Following a brief exposure to water flow, larvae show elevated activity and heightened sensitivity to perceived motion. Calcium imaging of neuronal activity after flow revealed increased activity in serotonergic neurons of the dorsal raphe. Genetic ablation of these neurons abolished the increase in visual sensitivity during arousal without affecting baseline visual function or locomotor activity. We traced projections from the dorsal raphe to a major visual area, the optic tectum. Laser ablation of the tectum demonstrated that this structure, like the dorsal raphe, is required for improved visual sensitivity during arousal. These findings reveal that serotonergic neurons of the dorsal raphe have a state-dependent role in matching sensory responsiveness to behavioral context. PMID:23100441

Near-infrared spectroscopy assessment of divided visual attention task-invoked cerebral hemodynamics during prolonged true driving

NASA Astrophysics Data System (ADS)

Li, Ting; Zhao, Yue; Sun, Yunlong; Gao, Yuan; Su, Yu; Hetian, Yiyi; Chen, Min

2015-03-01

Driver fatigue is one of the leading causes of traffic accidents. It is imperative to develop a technique to monitor fatigue of drivers in real situation. Near-infrared spectroscopy (fNIRS) is now capable of measuring brain functional activity noninvasively in terms of hemodynamic responses sensitively, which shed a light to us that it may be possible to detect fatigue-specified brain functional activity signal. We developed a sensitive, portable and absolute-measure fNIRS, and utilized it to monitor cerebral hemodynamics on car drivers during prolonged true driving. An odd-ball protocol was employed to trigger the drivers' visual divided attention, which is a critical function in safe driving. We found that oxyhemoglobin concentration and blood volume in prefrontal lobe dramatically increased with driving duration (stand for fatigue degree; 2-10 hours), while deoxyhemoglobin concentration increased to the top at 4 hours then decreased slowly. The behavior performance showed clear decrement only after 6 hours. Our study showed the strong potential of fNIRS combined with divided visual attention protocol in driving fatigue degree monitoring. Our findings indicated the fNIRS-measured hemodynamic parameters were more sensitive than behavior performance evaluation.

The Properties of HPMC:PEO Extended Release Hydrophilic Matrices and their Response to Ionic Environments.

PubMed

Hu, Anran; Chen, Chen; Mantle, Michael D; Wolf, Bettina; Gladden, Lynn F; Rajabi-Siahboomi, Ali; Missaghi, Shahrzad; Mason, Laura; Melia, Colin D

2017-05-01

Investigate the extended release behaviour of compacts containing mixtures of hydrophilic HPMC and PEO in hydrating media of differing ionic strengths. The extended release behaviour of various HPMC:PEO compacts was investigated using dissolution testing, confocal microscopy and magnetic resonance imaging, with respect to polymer ratio and ionic strength of the hydrating media. Increasing HPMC content gave longer extended release times, but a greater sensitivity to high ionic dissolution environments. Increasing PEO content reduced this sensitivity. The addition of PEO to a predominantly HPMC matrix reduced release rate sensitivity to high ionic environments. Confocal microscopy of early gel layer development showed the two polymers appeared to contribute independently to gel layer structure whilst together forming a coherent and effective diffusion barrier. There was some evidence that poorly swollen HPMC particles added a tortuosity barrier to the gel layer in high ionic strength environments, resulting in prolonged extended release. MRI provides unique, non-invasive spatially resolved information from within the HPMC:PEO compacts that furthers our understanding of USP 1 and USP 4 dissolution data. Confocal microscopy and MRI data show that combinations of HPMC and PEO have advantageous extended release properties, in comparison with matrices containing a single polymer.

Magnesium Oxide (MgO) pH-sensitive Sensing Membrane in Electrolyte-Insulator-Semiconductor Structures with CF4 Plasma Treatment.

PubMed

Kao, Chyuan-Haur; Chang, Chia Lung; Su, Wei Ming; Chen, Yu Tzu; Lu, Chien Cheng; Lee, Yu Shan; Hong, Chen Hao; Lin, Chan-Yu; Chen, Hsiang

2017-08-03

Magnesium oxide (MgO) sensing membranes in pH-sensitive electrolyte-insulator-semiconductor structures were fabricated on silicon substrate. To optimize the sensing capability of the membrane, CF 4 plasma was incorporated to improve the material quality of MgO films. Multiple material analyses including FESEM, XRD, AFM, and SIMS indicate that plasma treatment might enhance the crystallization and increase the grain size. Therefore, the sensing behaviors in terms of sensitivity, linearity, hysteresis effects, and drift rates might be improved. MgO-based EIS membranes with CF 4 plasma treatment show promise for future industrial biosensing applications.

First- and second-order contrast sensitivity functions reveal disrupted visual processing following mild traumatic brain injury.

PubMed

Spiegel, Daniel P; Reynaud, Alexandre; Ruiz, Tatiana; Laguë-Beauvais, Maude; Hess, Robert; Farivar, Reza

2016-05-01

Vision is disrupted by traumatic brain injury (TBI), with vision-related complaints being amongst the most common in this population. Based on the neural responses of early visual cortical areas, injury to the visual cortex would be predicted to affect both 1(st) order and 2(nd) order contrast sensitivity functions (CSFs)-the height and/or the cut-off of the CSF are expected to be affected by TBI. Previous studies have reported disruptions only in 2(nd) order contrast sensitivity, but using a narrow range of parameters and divergent methodologies-no study has characterized the effect of TBI on the full CSF for both 1(st) and 2(nd) order stimuli. Such information is needed to properly understand the effect of TBI on contrast perception, which underlies all visual processing. Using a unified framework based on the quick contrast sensitivity function, we measured full CSFs for static and dynamic 1(st) and 2(nd) order stimuli. Our results provide a unique dataset showing alterations in sensitivity for both 1(st) and 2(nd) order visual stimuli. In particular, we show that TBI patients have increased sensitivity for 1(st) order motion stimuli and decreased sensitivity to orientation-defined and contrast-defined 2(nd) order stimuli. In addition, our data suggest that TBI patients' sensitivity for both 1(st) order stimuli and 2(nd) order contrast-defined stimuli is shifted towards higher spatial frequencies. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

K+ channel TASK-1 knockout mice show enhanced sensitivities to ataxic and hypnotic effects of GABA(A) receptor ligands.

PubMed

Linden, Anni-Maija; Aller, M Isabel; Leppä, Elli; Rosenberg, Per H; Wisden, William; Korpi, Esa R

2008-10-01

TASK two-pore-domain leak K(+) channels occur throughout the brain. However, TASK-1 and TASK-3 knockout (KO) mice have few neurological impairments and only mildly reduced sensitivities to inhalational anesthetics, contrasting with the anticipated functions and importance of these channels. TASK-1/-3 channel expression can compensate for the absence of GABA(A) receptors in GABA(A) alpha6 KO mice. To investigate the converse, we analyzed the behavior of TASK-1 and -3 KO mice after administering drugs with preferential efficacies at GABA(A) receptor subtypes: benzodiazepines (diazepam and flurazepam, active at alpha1betagamma2, alpha2betagamma2, alpha3betagamma2, and alpha5betagamma2 subtypes), zolpidem (alpha1betagamma2 subtype), propofol (beta2-3-containing receptors), gaboxadol (alpha4betadelta and alpha6betadelta subtypes), pregnanolone, and pentobarbital (many subtypes). TASK-1 KO mice showed increased motor impairment in rotarod and beam-walking tests after diazepam and flurazepam administration but not after zolpidem. They also showed prolonged loss of righting reflex induced by propofol and pentobarbital. Autoradiography indicated no change in GABA(A) receptor ligand binding levels. These altered behavioral responses to GABAergic drugs suggest functional up-regulation of alpha2beta2/3gamma2 and alpha3beta2/3gamma2 receptor subtypes in TASK-1 KO mice. In addition, female, but not male, TASK-1 KO mice were more sensitive to gaboxadol, suggesting an increased influence of alpha4betadelta or alpha6betadelta subtypes. The benzodiazepine sensitivity of TASK-3 KO mice was marginally increased. Our results underline that TASK-1 channels perform such key functions in the brain that compensation is needed for their absence. Furthermore, because inhalation anesthetics act partially through GABA(A) receptors, the up-regulation of GABA(A) receptor function in TASK-1 KO mice might mask TASK-1 channel's significance as a target for inhalation anesthetics.

Mitochondrial-related gene expression changes are sensitive to agonal-pH state: implications for brain disorders

PubMed Central

Vawter, MP; Tomita, H; Meng, F; Bolstad, B; Li, J; Evans, S; Choudary, P; Atz, M; Shao, L; Neal, C; Walsh, DM; Burmeister, M; Speed, T; Myers, R; Jones, EG; Watson, SJ; Akil, H; Bunney, WE

2010-01-01

Mitochondrial defects in gene expression have been implicated in the pathophysiology of bipolar disorder and schizophrenia. We have now contrasted control brains with low pH versus high pH and showed that 28% of genes in mitochondrial-related pathways meet criteria for differential expression. A majority of genes in the mitochondrial, chaperone and proteasome pathways of nuclear DNA-encoded gene expression were decreased with decreased brain pH, whereas a majority of genes in the apoptotic and reactive oxygen stress pathways showed an increased gene expression with a decreased brain pH. There was a significant increase in mitochondrial DNA copy number and mitochondrial DNA gene expression with increased agonal duration. To minimize effects of agonal-pH state on mood disorder comparisons, two classic approaches were used, removing all subjects with low pH and agonal factors from analysis, or grouping low and high pH as a separate variable. Three groups of potential candidate genes emerged that may be mood disorder related: (a) genes that showed no sensitivity to pH but were differentially expressed in bipolar disorder or major depressive disorder; (b) genes that were altered by agonal-pH in one direction but altered in mood disorder in the opposite direction to agonal-pH and (c) genes with agonal-pH sensitivity that displayed the same direction of changes in mood disorder. Genes from these categories such as NR4A1 and HSPA2 were confirmed with Q-PCR. The interpretation of postmortem brain studies involving broad mitochondrial gene expression and related pathway alterations must be monitored against the strong effect of agonal-pH state. Genes with the least sensitivity to agonal-pH could present a starting point for candidate gene search in neuropsychiatric disorders. PMID:16636682

ZnS/Al2S3 Layer as a Blocking Layer in Quantum Dot Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Vafapoor, Borzoo; Fathi, Davood; Eskandari, Mehdi

2017-12-01

In this research, the effect of treatment of the CdS/CdSe sensitized ZnO photoanode by ZnS, Al2S3, and ZnS/Al2S3 nanoparticles as a barrier layer on the performance of quantum dot sensitized solar cell is investigated. Current density-voltage (J-V) characteristics show that cell efficiency is enhanced from 3.62% to 4.82% with treatment of a CdS/CdSe/ZnS sensitized ZnO photoanode by Al2S3 nanoparticles. In addition, short- circuit current density (J sc) is increased from 11.5 mA/cm2 to 14.8 mA/cm2. The results extracted from electrochemical impedance spectroscopy indicate that charge transfer resistance (R ct) in photoanode/electrolyte interfaces decreases with deposition of Al2S3 nanoparticles on CdS/CdSe/ZnS sensitized ZnO photoanodes, while the chemical capacitance of photoanode (C μ ) and electron lifetime (t n) increase. Also, results revealed that cell performance is considerably decreased with the treatment of the AL2S3 blocking layer incorporated between ZnO nanorods and CdS/CdSe QDs.

ZnS/Al2S3 Layer as a Blocking Layer in Quantum Dot Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Vafapoor, Borzoo; Fathi, Davood; Eskandari, Mehdi

2018-03-01

In this research, the effect of treatment of the CdS/CdSe sensitized ZnO photoanode by ZnS, Al2S3, and ZnS/Al2S3 nanoparticles as a barrier layer on the performance of quantum dot sensitized solar cell is investigated. Current density-voltage ( J- V) characteristics show that cell efficiency is enhanced from 3.62% to 4.82% with treatment of a CdS/CdSe/ZnS sensitized ZnO photoanode by Al2S3 nanoparticles. In addition, short- circuit current density ( J sc) is increased from 11.5 mA/cm2 to 14.8 mA/cm2. The results extracted from electrochemical impedance spectroscopy indicate that charge transfer resistance ( R ct) in photoanode/electrolyte interfaces decreases with deposition of Al2S3 nanoparticles on CdS/CdSe/ZnS sensitized ZnO photoanodes, while the chemical capacitance of photoanode ( C μ ) and electron lifetime ( t n) increase. Also, results revealed that cell performance is considerably decreased with the treatment of the AL2S3 blocking layer incorporated between ZnO nanorods and CdS/CdSe QDs.

Eutrophication exacerbates the impact of climate warming on lake methane emission.

PubMed

Sepulveda-Jauregui, Armando; Hoyos-Santillan, Jorge; Martinez-Cruz, Karla; Walter Anthony, Katey M; Casper, Peter; Belmonte-Izquierdo, Yadira; Thalasso, Frédéric

2018-04-27

Net methane (CH 4 ) emission from lakes depends on two antagonistic processes: CH 4 production (methanogenesis) and CH 4 oxidation (methanotrophy). It is unclear how climate warming will affect the balance between these processes, particularly among lakes of different trophic status. Here we show that methanogenesis is more sensitive to temperature than methanotrophy, and that eutrophication magnifies this temperature sensitivity. Using laboratory incubations of water and sediment from ten tropical, temperate and subarctic lakes with contrasting trophic states, ranging from oligotrophic to hypereutrophic, we explored the temperature sensitivity of methanogenesis and methanotrophy. We found that both processes presented a higher temperature sensitivity in tropical lakes, followed by temperate, and subarctic lakes; but more importantly, we found that eutrophication triggered a higher temperature sensitivity. A model fed by our empirical data revealed that increasing lake water temperature by 2 °C leads to a net increase in CH 4 emissions by 101-183% in hypereutrophic lakes and 47-56% in oligotrophic lakes. We conclude that climate warming will tilt the CH 4 balance towards higher lake emission and that this impact will be exacerbated by the eutrophication of the lakes. Copyright © 2018 Elsevier B.V. All rights reserved.

Manipulative experiments demonstrate how long-term soil moisture changes alter controls of plant water use

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

Grossiord, Charlotte; Sevanto, Sanna Annika; Limousin, Jean -Marc

Tree transpiration depends on biotic and abiotic factors that might change in the future, including precipitation and soil moisture status. Although short-term sap flux responses to soil moisture and evaporative demand have been the subject of attention before, the relative sensitivity of sap flux to these two factors under long-term changes in soil moisture conditions has rarely been determined experimentally. We tested how long-term artificial change in soil moisture affects the sensitivity of tree-level sap flux to daily atmospheric vapor pressure deficit ( VPD) and soil moisture variations, and the generality of these effects across forest types and environments usingmore » four manipulative sites in mature forests. Exposure to relatively long-term (two to six years) soil moisture reduction decreases tree sap flux sensitivity to daily VPD and relative extractable water ( REW) variations, leading to lower sap flux even under high soil moisture and optimal VPD. Inversely, trees subjected to long-term irrigation showed a significant increase in their sensitivity to daily VPD and REW, but only at the most water-limited site. The ratio between the relative change in soil moisture manipulation and the relative change in sap flux sensitivity to VPD and REW variations was similar across sites suggesting common adjustment mechanisms to long-term soil moisture status across environments for evergreen tree species. Altogether, our results show that long-term changes in soil water availability, and subsequent adjustments to these novel conditions, could play a critical and increasingly important role in controlling forest water use in the future.« less

Manipulative experiments demonstrate how long-term soil moisture changes alter controls of plant water use

DOE PAGES

Grossiord, Charlotte; Sevanto, Sanna Annika; Limousin, Jean -Marc; ...

2017-12-14

Tree transpiration depends on biotic and abiotic factors that might change in the future, including precipitation and soil moisture status. Although short-term sap flux responses to soil moisture and evaporative demand have been the subject of attention before, the relative sensitivity of sap flux to these two factors under long-term changes in soil moisture conditions has rarely been determined experimentally. We tested how long-term artificial change in soil moisture affects the sensitivity of tree-level sap flux to daily atmospheric vapor pressure deficit ( VPD) and soil moisture variations, and the generality of these effects across forest types and environments usingmore » four manipulative sites in mature forests. Exposure to relatively long-term (two to six years) soil moisture reduction decreases tree sap flux sensitivity to daily VPD and relative extractable water ( REW) variations, leading to lower sap flux even under high soil moisture and optimal VPD. Inversely, trees subjected to long-term irrigation showed a significant increase in their sensitivity to daily VPD and REW, but only at the most water-limited site. The ratio between the relative change in soil moisture manipulation and the relative change in sap flux sensitivity to VPD and REW variations was similar across sites suggesting common adjustment mechanisms to long-term soil moisture status across environments for evergreen tree species. Altogether, our results show that long-term changes in soil water availability, and subsequent adjustments to these novel conditions, could play a critical and increasingly important role in controlling forest water use in the future.« less

Voltage-sensitive rhodol with enhanced two-photon brightness

PubMed Central

Kulkarni, Rishikesh U.; Kramer, Daniel J.; Pourmandi, Narges; Karbasi, Kaveh; Bateup, Helen S.

2017-01-01

We have designed, synthesized, and applied a rhodol-based chromophore to a molecular wire-based platform for voltage sensing to achieve fast, sensitive, and bright voltage sensing using two-photon (2P) illumination. Rhodol VoltageFluor-5 (RVF5) is a voltage-sensitive dye with improved 2P cross-section for use in thick tissue or brain samples. RVF5 features a dichlororhodol core with pyrrolidyl substitution at the nitrogen center. In mammalian cells under one-photon (1P) illumination, RVF5 demonstrates high voltage sensitivity (28% ΔF/F per 100 mV) and improved photostability relative to first-generation voltage sensors. This photostability enables multisite optical recordings from neurons lacking tuberous sclerosis complex 1, Tsc1, in a mouse model of genetic epilepsy. Using RVF5, we show that Tsc1 KO neurons exhibit increased activity relative to wild-type neurons and additionally show that the proportion of active neurons in the network increases with the loss of Tsc1. The high photostability and voltage sensitivity of RVF5 is recapitulated under 2P illumination. Finally, the ability to chemically tune the 2P absorption profile through the use of rhodol scaffolds affords the unique opportunity to image neuronal voltage changes in acutely prepared mouse brain slices using 2P illumination. Stimulation of the mouse hippocampus evoked spiking activity that was readily discerned with bath-applied RVF5, demonstrating the utility of RVF5 and molecular wire-based voltage sensors with 2P-optimized fluorophores for imaging voltage in intact brain tissue. PMID:28242676

Manipulative experiments demonstrate how long-term soil moisture changes alter controls of plant water use

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

Grossiord, Charlotte; Sevanto, Sanna; Limousin, Jean-Marc

Tree transpiration depends on biotic and abiotic factors that might change in the future, including precipitation and soil moisture status. Although short-term sap flux responses to soil moisture and evaporative demand have been the subject of attention before, the relative sensitivity of sap flux to these two factors under long-term changes in soil moisture conditions has rarely been determined experimentally. We tested how long-term artificial change in soil moisture affects the sensitivity of tree-level sap flux to daily atmospheric vapor pressure deficit (VPD) and soil moisture variations, and the generality of these effects across forest types and environments using fourmore » manipulative sites in mature forests. Exposure to relatively long-term (two to six years) soil moisture reduction decreases tree sap flux sensitivity to daily VPD and relative extractable water (REW) variations, leading to lower sap flux even under high soil moisture and optimal VPD. Inversely, trees subjected to long-term irrigation showed a significant increase in their sensitivity to daily VPD and REW, but only at the most water-limited site. The ratio between the relative change in soil moisture manipulation and the relative change in sap flux sensitivity to VPD and REW variations was similar across sites suggesting common adjustment mechanisms to long-term soil moisture status across environments for evergreen tree species. Overall, our results show that long-term changes in soil water availability, and subsequent adjustments to these novel conditions, could play a critical and increasingly important role in controlling forest water use in the future.« less

Prediction of venous wound healing with laser speckle imaging.

PubMed

van Vuuren, Timme Maj; Van Zandvoort, Carina; Doganci, Suat; Zwiers, Ineke; tenCate-Hoek, Arina J; Kurstjens, Ralph Lm; Wittens, Cees Ha

2017-12-01

Introduction Laser speckle imaging is used for noninvasive assessment of blood flow of cutaneous wounds. The aim of this study was to assess if laser speckle imaging can be used as a predictor of venous ulcer healing. Methods After generating the flux speckle images, three regions of interest (ROI) were identified to measure the flow. Sensitivity, specificity, negative predictive value, and positive predictive value for ulcer healing were calculated. Results In total, 17 limbs were included. A sensitivity of 92.3%, specificity of 75.0%, PPV of 80.0%, and NPV 75.0% were found in predicting wound healing based on laser speckle images. Mean flux values were lowest in the center (ROI I) and showed an increase at the wound edge (ROI II, p = 0.03). Conclusion Laser speckle imaging shows acceptable sensitivity and specificity rates in predicting venous ulcer healing. The wound edge proved to be the best probability for the prediction of wound healing.

Face processing regions are sensitive to distinct aspects of temporal sequence in facial dynamics.

PubMed

Reinl, Maren; Bartels, Andreas

2014-11-15

Facial movement conveys important information for social interactions, yet its neural processing is poorly understood. Computational models propose that shape- and temporal sequence sensitive mechanisms interact in processing dynamic faces. While face processing regions are known to respond to facial movement, their sensitivity to particular temporal sequences has barely been studied. Here we used fMRI to examine the sensitivity of human face-processing regions to two aspects of directionality in facial movement trajectories. We presented genuine movie recordings of increasing and decreasing fear expressions, each of which were played in natural or reversed frame order. This two-by-two factorial design matched low-level visual properties, static content and motion energy within each factor, emotion-direction (increasing or decreasing emotion) and timeline (natural versus artificial). The results showed sensitivity for emotion-direction in FFA, which was timeline-dependent as it only occurred within the natural frame order, and sensitivity to timeline in the STS, which was emotion-direction-dependent as it only occurred for decreased fear. The occipital face area (OFA) was sensitive to the factor timeline. These findings reveal interacting temporal sequence sensitive mechanisms that are responsive to both ecological meaning and to prototypical unfolding of facial dynamics. These mechanisms are temporally directional, provide socially relevant information regarding emotional state or naturalness of behavior, and agree with predictions from modeling and predictive coding theory. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Photoresponse and learning behavior of ascidian larvae, a primitive chordate, to repeated stimuli of step-up and step-down of light.

PubMed

Kawakami, I; Shiraishi, S; Tsuda, M

2002-09-01

Ascidians are lower chordates and their simple tadpole-like larvae share a basic body plan with vertebrates. Newly hatched larvae show no response to a stimulus of light. 4 h after hatching, the larvae were induced to swim upon a step-down of light and stop swimming upon a step-up of light. At weaker intensity of light, the larvae show the same response to a stimulus after presentation of repeated stimuli. When intensity of actinic light was increased, the larvae show sensitization and habituation of the swimming response to a stimulus after repeated stimuli of step-down and step-up of the light. Between 2 h 20 min and 3 h 40 min after hatching the larvae did not show any response to the first stimulus, but after several repeatedstimuli they show swimming response to a step-down of light. A repeated series of stimulus cause sensitization. Between 4 h and 7 h after hatching, the larvae show photoresponse to the first stimulus, but after several repetition of the stimuli, the larvae could not stop swimming to a stimulus of a step-up of the actinic light. A repeated series of stimulus cause greaterhabituation. Both sensitization and habituation depend upon intensity ofactinic light.

The Effects of Ionizing Radiation and Oxidizing Species on Strains of Deinococcus Radiodurans Lacking Endogenous Oxidative Protection Methods

DTIC Science & Technology

Deinococcus radiodurans. In addition to radiation the mutated strains were also exposed to paraquat, an oxidizing herbicide . Strains missing manganese super-oxide dismutase and bacillithiol synthesis showed increased sensitivity.

Highly sensitive wearable strain sensor based on silver nanowires and nanoparticles.

PubMed

Shengbo, Sang; Lihua, Liu; Aoqun, Jian; Qianqian, Duan; Jianlong, Ji; Qiang, Zhang; Wendong, Zhang

2018-06-22

Here, we propose a highly sensitive and stretchable strain sensor based on silver nanoparticles and nanowires (Ag NPs and NWs), advancing the rapid development of electronic skin. To improve the sensitivity of strain sensors based on silver nanowires (Ag NWs), Ag NPs and NWs were added to polydimethylsiloxane (PDMS) as an aid filler. Silver nanoparticles (Ag NPs) increase the conductive paths for electrons, leading to the low resistance of the resulting sensor (14.9 Ω). The strain sensor based on Ag NPs and NWs showed strong piezoresistivity with a tunable gauge factor (GF) at 3766, and a change in resistance as the strain linearly increased from 0% to 28.1%. The high GF demonstrates the irreplaceable role of Ag NPs in the sensor. Moreover, the applicability of our high-performance strain sensor has been demonstrated by its ability to sense movements caused by human talking, finger bending, wrist raising and walking.

Absence of cross-resistance between two alkylating agents: BCNU vs bifunctional galactitol.

PubMed

Institóris, E; Szikla, K; Otvös, L; Gál, F

1989-01-01

Dianhydrogalactitol (DAG) increased the life span of both BCNU-sensitive and -resistant L1210 tumor-bearing mice. However, the BCNU-resistant strain showed slightly lower sensitivity against DAG, which could be overcome by an increase in drug dose of ca. 20%. The somewhat lower sensitivity was proportional to a slightly reduced DNA cross-linking formation induced by DAG in BCNU-resistant cells. The amount of DNA cross-links was determined by measurement of the 1,6-di(guaninyl)-galactitol content of DNA. The slight reduction in cross-links is not attributable to DNA repair but rather to other factors that seem to prevent the formation of DNA-drug adducts. The absence of cross-resistance is explained by different kinds of DNA damage caused by the two alkylating agents and the presumably different defense mechanisms developed by cells against these lesions.

[Study on preparation of the pH sensitive hydroxyethyl chitin/poly (acrylic acid) hydrogel and its drug release property].

PubMed

Zhao, Yu; Chen, Guohua; Sun, Mingkun; Jin, Zhitao; Gao, Congjie

2006-04-01

Hydroxyethyl chitin (HECH) is a water soluble chitin derivative made by etherification of chitin, ethylene chlorohydrin was used as etherification reagent in this reaction. A novel interpenetrating polymer network (IPN) composed of HECH/PAA was prepared. The IR spectra confirmed that HECH/PAA was formed through chemical bond interaction. The sensitivity of this hydrogel to temperature and pH was studied. The swelling ratio of this hydrogel in artificial intestinal juice is much greater than that in artificial gastric juice. The IPN hydrogel exhibited a typical pH-sensitivity, and its degree of swelling ratio increased with the increase of temperature. The sustained-release drug system of Dichlofenac potassium was prepared by using HECH/PAA as the drug carrier. The release experiment showed a perfect release behavior in artificial intestinal juice. This IPN is expected to be used as a good drug delivery system of enteric medicine.

Enzymatic amplification of a flow-injected thermometric enzyme-linked immunoassay for human insulin.

PubMed

Mecklenburg, M; Lindbladh, C; Li, H; Mosbach, K; Danielsson, B

1993-08-01

A flow-injected thermometric enzyme linked immunoassay for human insulin which employs the lactate dehydrogenase/lactate oxidase (LDH/LOD) substrate recycling system for signal amplification is described. The system is composed of two columns, an immunosorbent column containing immobilized anti-insulin antibodies for sensing and a recycling column containing immobilized LDH/LOD/Catalase for detection. The effect of flow rates, conjugate concentrations, and chromatographic support material upon the sensitivity of the assay are investigated. The assay has a detection limit of 0.025 microgram/ml and a linear range from 0.05 to 2 micrograms/ml. This corresponds to a 10-fold increase in sensitivity over the unamplified system. A recombinant human insulin-proinsulin conjugate was also tested. The results show that enzymatic amplification can be employed to increase the sensitivity and reproducibility of flow injection assay-based biosensors. The implications of these results upon on-line analysis are discussed.

Polarization Sensitive Coherent Anti-Stokes Raman Spectroscopy of DCVJ in Doped Polymer

NASA Astrophysics Data System (ADS)

Ujj, Laszlo

2014-05-01

Coherent Raman Microscopy is an emerging technic and method to image biological samples such as living cells by recording vibrational fingerprints of molecules with high spatial resolution. The race is on to record the entire image during the shortest time possible in order to increase the time resolution of the recorded cellular events. The electronically enhanced polarization sensitive version of Coherent anti-Stokes Raman scattering is one of the method which can shorten the recording time and increase the sharpness of an image by enhancing the signal level of special molecular vibrational modes. In order to show the effectiveness of the method a model system, a highly fluorescence sample, DCVJ in a polymer matrix is investigated. Polarization sensitive resonance CARS spectra are recorded and analyzed. Vibrational signatures are extracted with model independent methods. Details of the measurements and data analysis will be presented. The author gratefully acknowledge the UWF for financial support.

Enhancing the humidity sensitivity of Ga2O3 /SnO2 core/shell microribbon by applying mechanical strain and its application as a flexible strain sensor.

PubMed

Liu, Kewei; Sakurai, Makoto; Aono, Masakazu

2012-12-07

The humidity sensitivity of a single β-Ga(2) O(3) /amorphous SnO(2) core/shell microribbon on a flexible substrate is enhanced by the application of tensile strain and increases linearly with the strain. The strain-induced enhancement originates from the increase in the effective surface area where water molecules are adsorbed. This strain dependence of humidity sensitivity can be used to monitor the external strain. The strain sensing of the microribbon device under various amounts of mechanical loading shows excellent reliability and reproducibility with a gauge factor of -41. The flexible device has high potential to detect both humidity and strain at room temperature. These findings and the mechanism involved are expected to pave the way for new flexible strain and multifunctional sensors. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly sensitive wearable strain sensor based on silver nanowires and nanoparticles

NASA Astrophysics Data System (ADS)

Shengbo, Sang; Lihua, Liu; Aoqun, Jian; Qianqian, Duan; Jianlong, Ji; Qiang, Zhang; Wendong, Zhang

2018-06-01

Here, we propose a highly sensitive and stretchable strain sensor based on silver nanoparticles and nanowires (Ag NPs and NWs), advancing the rapid development of electronic skin. To improve the sensitivity of strain sensors based on silver nanowires (Ag NWs), Ag NPs and NWs were added to polydimethylsiloxane (PDMS) as an aid filler. Silver nanoparticles (Ag NPs) increase the conductive paths for electrons, leading to the low resistance of the resulting sensor (14.9 Ω). The strain sensor based on Ag NPs and NWs showed strong piezoresistivity with a tunable gauge factor (GF) at 3766, and a change in resistance as the strain linearly increased from 0% to 28.1%. The high GF demonstrates the irreplaceable role of Ag NPs in the sensor. Moreover, the applicability of our high-performance strain sensor has been demonstrated by its ability to sense movements caused by human talking, finger bending, wrist raising and walking.

Electronic characterization of lithographically patterned microcoils for high sensitivity NMR detection.

PubMed

Demas, Vasiliki; Bernhardt, Anthony; Malba, Vince; Adams, Kristl L; Evans, Lee; Harvey, Christopher; Maxwell, Robert S; Herberg, Julie L

2009-09-01

Nuclear magnetic resonance (NMR) offers a non-destructive, powerful, structure-specific analytical method for the identification of chemical and biological systems. The use of radio frequency (RF) microcoils has been shown to increase the sensitivity in mass-limited samples. Recent advances in micro-receiver technology have further demonstrated a substantial increase in mass sensitivity [D.L. Olson, T.L. Peck, A.G. Webb, R.L. Magin, J.V. Sweedler, High-resolution microcoil H-1-NMR for mass-limited, nanoliter-volume samples, Science 270 (5244) (1995) 1967-1970]. Lithographic methods for producing solenoid microcoils possess a level of flexibility and reproducibility that exceeds previous production methods, such as hand winding microcoils. This paper presents electrical characterizations of RF microcoils produced by a unique laser lithography system that can pattern three dimensional surfaces and compares calculated and experimental results to those for wire wound RF microcoils. We show that existing optimization conditions for RF coil design still hold true for RF microcoils produced by lithography. Current lithographic microcoils show somewhat inferior performance to wire wound RF microcoils due to limitations in the existing electroplating technique. In principle, however, when the pitch of the RF microcoil is less than 100mum lithographic coils should show comparable performance to wire wound coils. In the cases of larger pitch, wire cross sections can be significantly larger and resistances lower than microfabricated conductors.

Nasal bone length: prenasal thickness ratio: a strong 2D ultrasound marker for Down syndrome

PubMed Central

Szabó, Andrea; Szili, Károly; Szabó, János Tamás; Sikovanyecz, János; Isaszegi, Dóra; Horváth, Emese; Szabó, János

2014-01-01

Objectives To evaluate the feasibility of incorporating two-dimensional ultrasound measurements of nasal bone length (NBL) and prenasal thickness (PT) into the second-trimester anomaly scan and to determine whether the NBL : PT ratio could help in differentiating euploid and Down syndrome fetuses. Method Two-dimensional measurements of NBL and PT were obtained from the midsagittal plane of the fetal head at 14–28 weeks of gestation in a Caucasian population at risk for aneuploidy. The screening performances of NBL, PT, and the ratios NBL : PT and PT : NBL were analyzed in euploid (n = 1330) and Down syndrome (n = 33) fetuses. Results Nasal bone length and PT alone showed strong correlations with Down syndrome (sensitivity: 76% at 1.88% and 2.35% false positive rate, respectively). However, the NBL : PT ratio showed an even stronger correlation with Down syndrome (false positive rate: 0.9%, sensitivity: 97%). The mean NBL : PT ratio showed a gradual increase from 1.48 to 1.79 (a 21.2% increase) between 14 and 28 weeks of gestation. Conclusion Two-dimensional ultrasound measurements of NBL and PT, particularly the NBL : PT ratio, are highly sensitive markers for Down syndrome fetuses. © 2014 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd. PMID:24966049

Design of An Improved Miniature Ion Neutral Mass Spectrometer for NASA Applications

NASA Technical Reports Server (NTRS)

Swaminathan, Viji K.; Alig, Roger C.

1997-01-01

The ion optics of NASA's Ion Neutral Mass Spectrometer (INMS) sensor was simulated with three dimensional models of the open source, the quadrupole deflector, the exit lens system and the quadrupole mass analyzer to design more compact models with lower weight. Comparison of calculated transmission with experimental results shows good agreement. Transmission analyses with varying geometrical parameters and voltages throw light on possible ways of reducing the size of the sensor. Trajectories of ions of mass 1-99 amu were simulated to analyze and optimize transmission. Analysis of open source transmission with varying angle of attack shows that the angular acceptance can be considerably increased by programming the voltages on the ion trap/ collimator. Analysis of transmission sensitivity to voltages and misalignments of the quadrupole deflector rods indicate that increased transmission is possible with a geometrically asymmetrical deflector and a deflector can be designed with much lower sensitivities of transmission. Bringing the disks closer together can decrease the size of the quadrupole deflector and also increase transmission. The exit lens system can be redesigned to be smaller by eliminating at least one electrode entirely without loss of transmission. Ceramic materials were investigated to find suitable candidates for use in the construction of lighter weight mass spectrometer. A high-sensitivity, high-resolution portable gas chromatograph mass spectrometer with a mass range of 2-700 amu has been built and will be commercialized in Phase 3.

Assessing change in sensitivity of tropical vegetation to climate based on wavelet analysis

NASA Astrophysics Data System (ADS)

Claessen, J.; Martens, B.; Verhoest, N.; Molini, A.; Miralles, D. G.

2017-12-01

Vegetation dynamics are driven by climate, and at the same time they play a key role in forcing the different bio-geochemical cycles. As climate change leads to an increase in frequency and intensity of hydro-meteorological extremes, vegetation is expected to respond to these changes, and subsequently feed back on their occurrence. Future responses can be better understood by analysing the past using time series of different vegetation diagnostics observed from space, both in the optical and microwave domain. In this contribution, the climatic drivers (air temperature, precipitation, and incoming radiation) of these different vegetation diagnostics are analysed using a monthly global data-cube of 32 years at a 0.25° resolution. To do so, we analyse the wavelet coherence between each vegetation index and the climatic drivers of vegetation. The use of wavelet coherence allows unveiling the different response and sensitivity of the diverse vegetation indices to their climatic drivers, simultaneously in the time and frequency domains. Our results show that the wavelet-based statistics are suitable for extracting information from the different vegetation indices. Areas of high rainfall volumes are characterised by a strong control of radiation and temperature over vegetation. At higher latitudes, the positive trends in all vegetation diagnostics agree with the hypothesis of a greening pattern, which is coherent with the increase in temperature. At the same time, substantial differences can be observed between the responses of the different vegetation indices as well. As an example, the VOD - thought to be a close proxy for vegetation water content - shows a larger sensitivity to precipitation than traditional optical indices such as the NDVI. Further, important temporal changes in the wavelet coherence between vegetation and climate are identified. For instance, the Amazonian rainforest shows an increased correspondence with precipitation dynamics, indicating positive shifts in ecosystem sensitivity to water availability, which can arguably be related to an increase in the amplitude of the seasonal cycle in rainfall. These results are in line with the expected intensification of the water cycle due to climate change and point to the complex response of the biosphere to climatic changes.

Task-dependent enhancement of facial expression and identity representations in human cortex.

PubMed

Dobs, Katharina; Schultz, Johannes; Bülthoff, Isabelle; Gardner, Justin L

2018-05-15

What cortical mechanisms allow humans to easily discern the expression or identity of a face? Subjects detected changes in expression or identity of a stream of dynamic faces while we measured BOLD responses from topographically and functionally defined areas throughout the visual hierarchy. Responses in dorsal areas increased during the expression task, whereas responses in ventral areas increased during the identity task, consistent with previous studies. Similar to ventral areas, early visual areas showed increased activity during the identity task. If visual responses are weighted by perceptual mechanisms according to their magnitude, these increased responses would lead to improved attentional selection of the task-appropriate facial aspect. Alternatively, increased responses could be a signature of a sensitivity enhancement mechanism that improves representations of the attended facial aspect. Consistent with the latter sensitivity enhancement mechanism, attending to expression led to enhanced decoding of exemplars of expression both in early visual and dorsal areas relative to attending identity. Similarly, decoding identity exemplars when attending to identity was improved in dorsal and ventral areas. We conclude that attending to expression or identity of dynamic faces is associated with increased selectivity in representations consistent with sensitivity enhancement. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Allergic contact dermatitis from ophthalmic products: can pre-treatment with sodium lauryl sulfate increase patch test sensitivity?

PubMed

Corazza, Monica; Virgili, Annarosa

2005-05-01

In patients suspected of allergic contact dermatitis because of topical ophthalmic medicaments, patch tests performed with patients' own products are often negative. The irritant anionic surfactant sodium lauryl sulfate (SLS) may alter the stratum corneum and increase antigen penetration. Pre-treatment of the skin with SLS 0.5% for 24 h was performed in the sites of patch tests with patients' own products in 15 selected patients. In patients previously negative to their own products tested with conventional patch tests, SLS pre-treatment showed 6 new relevant positive reactions and induced a stronger positive reaction in 1 patient. SLS pre-treatment could be proposed as an alternative promising method, which may increase sensitivity of patch tests with patients' own products.

The Effect of an Increased Convective Entrainment Rate on Indian Monsoon Biases in the Met Office Unified Model

NASA Astrophysics Data System (ADS)

Bush, Stephanie; Turner, Andrew; Woolnough, Steve; Martin, Gill

2013-04-01

Global circulation models (GCMs) are a key tool for understanding and predicting monsoon rainfall, now and under future climate change. However, many GCMs show significant, systematic biases in their simulation of monsoon rainfall and dynamics that spin up over very short time scales and persist in the climate mean state. We describe several of these biases as simulated in the Met Office Unified Model and show they are sensitive to changes in the convective parameterization's entrainment rate. To improve our understanding of the biases and inform efforts to improve convective parameterizations, we explore the reasons for this sensitivity. We show the results of experiments where we increase the entrainment rate in regions of especially large bias: the western equatorial Indian Ocean, western north Pacific and India itself. We use the results to determine whether improvements in biases are due to the local increase in entrainment or are the remote response of the entrainment increase elsewhere in the GCM. We find that feedbacks usually strengthen the local response, but the local response leads to a different mean state change in different regions. We also show results from experiments which demonstrate the spin-up of the local response, which we use to further understand the response in complex regions such as the Western North Pacific. Our work demonstrates that local application of parameterization changes is a powerful tool for understanding their global impact.

CNS neuroplasticity and salt-sensitive hypertension induced by prior treatment with subpressor doses of ANG II or aldosterone.

PubMed

Clayton, Sarah C; Zhang, Zhongming; Beltz, Terry; Xue, Baojian; Johnson, Alan Kim

2014-06-15

Although sensitivity to high dietary NaCl is regarded to be a risk factor for cardiovascular disease, the causes of salt-sensitive hypertension remain elusive. Previously, we have shown that rats pretreated with subpressor doses of either ANG II or aldosterone (Aldo) show sensitized hypertensive responses to a mild pressor dose of ANG II when tested after an intervening delay. The current studies investigated whether such treatments will induce salt sensitivity. In studies employing an induction-delay-expression experimental design, male rats were instrumented for chronic mean arterial pressure (MAP) recording. In separate experiments, ANG II, Aldo, or vehicle was delivered either subcutaneously or intracerebroventricularly during the induction. There were no sustained differences in BP during the delay prior to being given 2% saline. While consuming 2% saline during the expression, both ANG II- and Aldo-pretreated rats showed significantly greater hypertension. When hexamethonium was used to assess autonomic control of MAP, no differences in the decrease of MAP in response to ganglionic blockade were detected during the induction. However, during the expression, the fall was greater in sensitized rats. In separate experiments, brain tissue that was collected at the end of delay showed increases in message or activation of putative markers of neuroplasticity (i.e., brain-derived neurotrophic factor, p38 mitogen-activated protein kinase, and cAMP response element-binding protein). These experiments demonstrate that prior administration of nonpressor doses of either ANG II or Aldo will induce salt sensitivity. Collectively, our findings indicate that treatment with subpressor doses of ANG II and Aldo initiate central neuroplastic changes that are involved in hypertension of different etiologies. Copyright © 2014 the American Physiological Society.

Effect of Ultrasonic Nano-Crystal Surface Modification (UNSM) on the Passivation Behavior of Aged 316L Stainless Steel

PubMed Central

Kim, Ki-Tae; Lee, Jung-Hee; Kim, Young-Sik

2017-01-01

Stainless steels have good corrosion resistance in many environments but welding or aging can decrease their resistance. This work focused on the effect of aging time and ultrasonic nano-crystal surface modification on the passivation behavior of 316L stainless steel. In the case of slightly sensitized 316L stainless steel, increasing the aging time drastically decreased the pitting potential, increased the passive current density, and decreased the resistance of the passive film, even though aging did not form chromium carbide and a chromium depletion zone. This behavior is due to the micro-galvanic corrosion between the matrix and carbon segregated area, and this shows the importance of carbon segregation in grain boundaries to the pitting corrosion resistance of stainless steel, in addition to the formation of the chromium depletion zone. UNSM (Ultrasonic Nano Crystal Surface Modification)-treatment to the slightly sensitized 316L stainless steel increased the pitting potential, decreased the passive current density, and increased the resistance of the passive film. However, in the case of heavily sensitized 316L stainless steel, UNSM-treatment decreased the pitting potential, increased the passive current density, and decreased the resistance of the passive film. This behavior is due to the dual effects of the UNSM-treatment. That is, the UNSM-treatment reduced the carbon segregation, regardless of whether the stainless steel 316L was slightly or heavily sensitized. However, since this treatment made mechanical flaws in the outer surface in the case of the heavily sensitized stainless steel, UNSM-treatment may eliminate chromium carbide, and this flaw can be a pitting initiation site, and therefore decrease the pitting corrosion resistance. PMID:28773067

Effect of Ultrasonic Nano-Crystal Surface Modification (UNSM) on the Passivation Behavior of Aged 316L Stainless Steel.

PubMed

Kim, Ki-Tae; Lee, Jung-Hee; Kim, Young-Sik

2017-06-27

Stainless steels have good corrosion resistance in many environments but welding or aging can decrease their resistance. This work focused on the effect of aging time and ultrasonic nano-crystal surface modification on the passivation behavior of 316L stainless steel. In the case of slightly sensitized 316L stainless steel, increasing the aging time drastically decreased the pitting potential, increased the passive current density, and decreased the resistance of the passive film, even though aging did not form chromium carbide and a chromium depletion zone. This behavior is due to the micro-galvanic corrosion between the matrix and carbon segregated area, and this shows the importance of carbon segregation in grain boundaries to the pitting corrosion resistance of stainless steel, in addition to the formation of the chromium depletion zone. UNSM (Ultrasonic Nano Crystal Surface Modification)-treatment to the slightly sensitized 316L stainless steel increased the pitting potential, decreased the passive current density, and increased the resistance of the passive film. However, in the case of heavily sensitized 316L stainless steel, UNSM-treatment decreased the pitting potential, increased the passive current density, and decreased the resistance of the passive film. This behavior is due to the dual effects of the UNSM-treatment. That is, the UNSM-treatment reduced the carbon segregation, regardless of whether the stainless steel 316L was slightly or heavily sensitized. However, since this treatment made mechanical flaws in the outer surface in the case of the heavily sensitized stainless steel, UNSM-treatment may eliminate chromium carbide, and this flaw can be a pitting initiation site, and therefore decrease the pitting corrosion resistance.

An Animal Model of Trichloroethylene-Induced Skin Sensitization in BALB/c Mice.

PubMed

Wang, Hui; Zhang, Jia-xiang; Li, Shu-long; Wang, Feng; Zha, Wan-sheng; Shen, Tong; Wu, Changhao; Zhu, Qi-xing

2015-01-01

Trichloroethylene (TCE) is a major occupational hazard and environmental contaminant that can cause multisystem disorders in the form of occupational medicamentosa-like dermatitis. Development of dermatitis involves several proinflammatory cytokines, but their role in TCE-mediated dermatitis has not been examined in a well-defined experimental model. In addition, few animal models of TCE sensitization are available, and the current guinea pig model has apparent limitations. This study aimed to establish a model of TCE-induced skin sensitization in BALB/c mice and to examine the role of several key inflammatory cytokines on TCE sensitization. The sensitization rate of dorsal painted group was 38.3%. Skin edema and erythema occurred in TCE-sensitized groups, as seen in 2,4-dinitrochlorobenzene (DNCB) positive control. Trichloroethylene sensitization-positive (dermatitis [+]) group exhibited increased thickness of epidermis, inflammatory cell infiltration, swelling, and necrosis in dermis and around hair follicle, but ear painted group did not show these histological changes. The concentrations of serum proinflammatory cytokines including tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and interleukin (IL)-2 were significantly increased in 24, 48, and 72 hours dermatitis [+] groups treated with TCE and peaked at 72 hours. Deposition of TNF-α, IFN-γ, and IL-2 into the skin tissue was also revealed by immunohistochemistry. We have established a new animal model of skin sensitization induced by repeated TCE stimulations, and we provide the first evidence that key proinflammatory cytokines including TNF-α, IFN-γ, and IL-2 play an important role in the process of TCE sensitization. © The Author(s) 2015.

Climate sensitivity, sea level and atmospheric carbon dioxide

PubMed Central

Hansen, James; Sato, Makiko; Russell, Gary; Kharecha, Pushker

2013-01-01

Cenozoic temperature, sea level and CO2 covariations provide insights into climate sensitivity to external forcings and sea-level sensitivity to climate change. Climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise palaeoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity of 3±1°C for a 4 W m−2 CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene. Glacial-to-interglacial climate change leading to the prior (Eemian) interglacial is less ambiguous and implies a sensitivity in the upper part of the above range, i.e. 3–4°C for a 4 W m−2 CO2 forcing. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify the total Earth system sensitivity by an amount that depends on the time scale considered. Ice sheet response time is poorly defined, but we show that the slow response and hysteresis in prevailing ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state dependence of climate sensitivity, finding an increased sensitivity towards warmer climates, as low cloud cover is diminished and increased water vapour elevates the tropopause. Burning all fossil fuels, we conclude, would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change. PMID:24043864

Climate sensitivity, sea level and atmospheric carbon dioxide.

PubMed

Hansen, James; Sato, Makiko; Russell, Gary; Kharecha, Pushker

2013-10-28

Cenozoic temperature, sea level and CO2 covariations provide insights into climate sensitivity to external forcings and sea-level sensitivity to climate change. Climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise palaeoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity of 3±1(°)C for a 4 W m(-2) CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene. Glacial-to-interglacial climate change leading to the prior (Eemian) interglacial is less ambiguous and implies a sensitivity in the upper part of the above range, i.e. 3-4(°)C for a 4 W m(-2) CO2 forcing. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify the total Earth system sensitivity by an amount that depends on the time scale considered. Ice sheet response time is poorly defined, but we show that the slow response and hysteresis in prevailing ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state dependence of climate sensitivity, finding an increased sensitivity towards warmer climates, as low cloud cover is diminished and increased water vapour elevates the tropopause. Burning all fossil fuels, we conclude, would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change.

Does the hybrid light source (LED/laser) influence temperature variation on the enamel surface during 35% hydrogen peroxide bleaching? A randomized clinical trial.

PubMed

de Freitas, Patricia Moreira; Menezes, Andressa Nery; da Mota, Ana Carolina Costa; Simões, Alyne; Mendes, Fausto Medeiros; Lago, Andrea Dias Neves; Ferreira, Leila Soares; Ramos-Oliveira, Thayanne Monteiro

2016-01-01

The present study investigated how a hybrid light source (LED/laser) influences temperature variation on the enamel surfaces during 35% hydrogen peroxide (HP) bleaching. Effects on the whitening effectiveness and tooth sensitivity were analyzed. Twenty-two volunteers were randomly assigned to two different treatments in a split-mouth experimental model: group 1 (control), 35% HP; group 2 (experimental), 35% HP + LED/laser. Color evaluation was performed before treatment, and 7 and 14 days after completion of bleaching, using a color shade scale. Tooth sensitivity was assessed using a visual analog scale (VAS; before, immediately, and 24 hours after bleaching). During the bleaching treatment, thermocouple channels positioned on the tooth surfaces recorded the temperature. Data on color and temperature changes were subjected to statistical analysis (α = 5%). Tooth sensitivity data were evaluated descriptively. Groups 1 and 2 showed mean temperatures (± standard deviation) of 30.7 ± 1.2 °C and 34.1 ± 1.3 °C, respectively. It was found that there were statistically significant differences between the groups, with group 2 showing higher mean variation (P < .0001). The highest temperature variation occurred for group 2, with an increase of 5.3 °C at the enamel surface. The color change results showed no differences in bleaching between the two treatment groups (P = .177). The variation of the average temperature during the treatments was not statistically associated with color variation (P = .079). Immediately after bleaching, it was found that 36.4% of the subjects in group 2 had mild to moderate sensitivity. In group 1, 45.5% showed moderate sensitivity. In both groups, the sensitivity ceased within 24 hours. Hybrid light source (LED/ laser) influences temperature variation on the enamel surface during 35% HP bleaching and is not related to greater tooth sensitivity.

Inflammation-induced pain sensitization in men and women: does sex matter in experimental endotoxemia?

PubMed Central

Wegner, Alexander; Elsenbruch, Sigrid; Rebernik, Laura; Roderigo, Till; Engelbrecht, Elisa; Jäger, Marcus; Engler, Harald; Schedlowski, Manfred; Benson, Sven

2015-01-01

Abstract A role of the innate immune system is increasingly recognized as a mechanism contributing to pain sensitization. Experimental administration of the bacterial endotoxin lipopolysaccharide (LPS) constitutes a model to study inflammation-induced pain sensitization, but all existing human evidence comes from male participants. We assessed visceral and musculoskeletal pain sensitivity after low-dose LPS administration in healthy men and women to test the hypothesis that women show greater LPS-induced hyperalgesia compared with men. In this randomized, double-blind, placebo-controlled crossover study, healthy men (n = 20) and healthy women using oral contraceptives (n = 20) received an intravenous injection of 0.4 ng/kg body weight LPS or placebo. Pain sensitivity was assessed with established visceral and musculoskeletal pain models (ie, rectal pain thresholds; pressure pain thresholds for different muscle groups), together with a heartbeat perception (interoceptive accuracy) task. Plasma cytokines (tumor necrosis factor-α and interleukin-6) were measured along with state anxiety at baseline and up to 6-hour postinjection. Lipopolysaccharide application led to significant increases in plasma cytokines and state anxiety and decreased interoceptive awareness in men and women (P < 0.001, condition effects), with more pronounced LPS-induced cytokine increases in women (P < 0.05, interaction effects). Although both rectal and pressure pain thresholds were significantly decreased in the LPS condition (all P < 0.05, condition effect), no sex differences in endotoxin-induced sensitization were observed. In summary, LPS-induced systemic immune activation leads to visceral and musculoskeletal hyperalgesia, irrespective of biological sex. These findings support the broad applicability of experimental endotoxin administration as a translational preclinical model of inflammation-induced pain sensitization in both sexes. PMID:26058036

Effect of sodium acetate additive in successive ionic layer adsorption and reaction on the performance of CdS quantum-dot-sensitized solar cells

NASA Astrophysics Data System (ADS)

Liu, I.-Ping; Chen, Liang-Yih; Lee, Yuh-Lang

2016-09-01

Sodium acetate (NaAc) is utilized as an additive in cationic precursors of the successive ionic layer adsorption and reaction (SILAR) process to fabricate CdS quantum-dot (QD)-sensitized photoelectrodes. The effects of the NaAc concentration on the deposition rate and distribution of QDs in mesoporous TiO2 films, as well as on the performance of CdS-sensitized solar cells are studied. The experimental results show that the presence of NaAc can significantly accelerate the deposition of CdS, improve the QD distribution across photoelectrodes, and thereby, increase the performance of solar cells. These results are mainly attributed to the pH-elevation effect of NaAc to the cationic precursors which increases the electrostatic interaction of the TiO2 film to cadmium ions. The light-to-energy conversion efficiency of the CdS-sensitized solar cell increases with increasing concentration of the NaAc and approaches a maximum value (3.11%) at 0.05 M NaAc. Additionally, an ionic exchange is carried out on the photoelectrode to transform the deposited CdS into CdS1-xSex ternary QDs. The light-absorption range of the photoelectrode is extended and an exceptional power conversion efficiency of 4.51% is achieved due to this treatment.

Long-term sensitivity of soil carbon turnover to warming.

PubMed

Knorr, W; Prentice, I C; House, J I; Holland, E A

2005-01-20

The sensitivity of soil carbon to warming is a major uncertainty in projections of carbon dioxide concentration and climate. Experimental studies overwhelmingly indicate increased soil organic carbon (SOC) decomposition at higher temperatures, resulting in increased carbon dioxide emissions from soils. However, recent findings have been cited as evidence against increased soil carbon emissions in a warmer world. In soil warming experiments, the initially increased carbon dioxide efflux returns to pre-warming rates within one to three years, and apparent carbon pool turnover times are insensitive to temperature. It has already been suggested that the apparent lack of temperature dependence could be an artefact due to neglecting the extreme heterogeneity of soil carbon, but no explicit model has yet been presented that can reconcile all the above findings. Here we present a simple three-pool model that partitions SOC into components with different intrinsic turnover rates. Using this model, we show that the results of all the soil-warming experiments are compatible with long-term temperature sensitivity of SOC turnover: they can be explained by rapid depletion of labile SOC combined with the negligible response of non-labile SOC on experimental timescales. Furthermore, we present evidence that non-labile SOC is more sensitive to temperature than labile SOC, implying that the long-term positive feedback of soil decomposition in a warming world may be even stronger than predicted by global models.

Numerical Simulation of Pre-heated Confined PBX Charge Under Low Velocity

NASA Astrophysics Data System (ADS)

Hu, Cai; Wu, Yanqing; Huang, Fenglei; Liu, Yan; Explosion; damage Team

2017-06-01

Impact sensitivity and thermal safety are very important for explosive safety usage.To investigate the effect of thermal softening on impact sensitivity of HMX-based PBX, a finite element model aiming at pre-heated confined PBX charge sbujected to bullets impact has been established. The predicted ignition starting area of the explosive charge was evaluated based on volume strain and equivalent strain contours. It showed that the ignition starting area moves towards the center of the explosives from the surface with increase of heating temperature. The threshold velocity does not increase monotonically with the pre-heating temperature increases. Instead, the threshold velocity rises till 360 m/s when the cook-off temperature is lower than 75°, then decreases the increased temperature. The results imply that our PBX has the lowest impact sensitivity at about 75°. These numerical results agree very well with the corresponding experiment results conducted by Dai et al. The influence of thermal softening on the impact sensitivity has been analyzed. As the strength decreases, more impact energy will be absorbed. At the same time, shear resistance ability will be weaken and volume compression work may play a more important role to ignition. China National Nature Science Foundation (11572045), ``Science Challenging Program'' (JCKY2016212A501), opening fund from Safety ammunition research and Development Center (RMC2015B03).

[Skin sensitisation profiles to inhalant allergens for patients in Tétouan city (North West of Morocco)].

PubMed

Bardei, F; Bouziane, H; Kadiri, M; Rkiek, B; Tebay, A; Saoud, A

2016-08-01

The prevalence of respiratory allergies is increasing and is a serious global health problem. The objective of the study was to determine the prevalence of skin sensitization to inhalant allergens in patients consulting for respiratory allergy, to identify the main allergens involved and to evaluate the profile of skin prick-test reactivity related to sex, age and season. This retrospective study included 379 patients consulting during 2009-2012 in three private medical offices of Tetouan. Of the 379 patients, 39.6% were monosensitized and 60.4% polysensitized. The percentages of polysensitized patients were higher in patients exhibiting rhinoconjunctivitis and astma-rhinoconjunctivitis than in subjects with asthma. The prevalence of symptoms according to sex showed no significant difference (P=0.64). Regarding age, a significant difference was observed in the case of rhinoconjunctivitis (P<0.01), while asthma and asthma-rhinoconjunctivitis showed no significant difference. Sensitization to house dust mites was the most frequent followed by grasses, olives and Parietaria. The multiple correspondence analyses (ACM) showed that patients under 20-years of age with asthma and asthma-rhinoconjunctivitis profile are more associated with sensitization to mites during the spring and autumn. The 20-49-year age group was represented mainly by polysensitized patients with rhinoconjunctivitis. Sensitization to mites ranks first in Tetouan followed by the percentage of sensitized patients to grass pollen and olive. The ACM showed that the house dust mite asthma seems to affect more children and adolescents while the 20-49 year age of polysensitized group suffers significantly rhinoconjunctivitis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Effects of Aluminum Stress on Protective Enzyme Activity in Tie Guanyin leaves

NASA Astrophysics Data System (ADS)

Sun, JingWei; Du, NaiChen; Zhang, YunFeng

2018-01-01

The experiment was adopted to study the change of SOD, CAT and POD activity of Tie guanyin (new leaf and old leaf blade of different concentrations of aluminum stress; in this paper, 0 (CK), 40, 200, four gradients of 400mg/L concentration of Al3+ in acidic conditions, Tieguanyin tea leaf SOD, cat and POD activity changes. The results showed that high concentrations of aluminum stress on antioxidant enzyme system activity cannot continue to increase; at the same time showed that SOD is sensitive to aluminum toxicity concentration change, its sensitivity is higher than CAT and POD, SOD and CAT activity and the aging and decline of plant There was a positive correlation.

Refractive index sensing by Brillouin scattering in side-polished optical fibers.

PubMed

Bernini, Romeo; Persichetti, Gianluca; Catalano, Ester; Zeni, Luigi; Minardo, Aldo

2018-05-15

In this Letter, we demonstrate the possibility to measure the refractive index of a liquid, using the stimulating Brillouin scattering in a 3-cm-long side-polished optical fiber. In addition, we show that by depositing a high-refractive index layer on the polished surface the sensitivity of the Brillouin frequency shift (BFS) can be increased due to a higher penetration of the evanescent field in the outer medium. Experiments show a maximum BFS change of about 11 MHz when varying the refractive index of the external medium from 1 (air) to 1.402, and a BFS sensitivity to refractive index of about 293 MHz/RIU around 1.40.

Increased risk of horse sensitization in southwestern Iranian horse riders.

PubMed

Moghtaderi, Mozhgan; Farjadian, Shirin; Hosseini, Zeynab; Raayat, Alireza

2015-01-01

The aim of this study has been to investigate the frequency of sensitization to horse allergens and clinical symptoms in horse riders. A total of 42 horse riders and 50 healthy individuals were examined by means of skin prick tests for a panel of horse and common animal allergens, and pulmonary function tests were done by spirometry. The rate of sensitization to horse allergens was 31% as proven by the skin prick test in horse riders whereas horse sensitization was not seen in the control group. Occupational allergy symptoms were reported by 19 horse riders. Two horse riders with no history of clinical symptoms showed positive skin reactions to horse allergens. To decrease the high risk of occupational sensitization among horse riders, workplace conditions should be improved to reduce the load of airborne horse allergens. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Characterization of a Novel MMS-Sensitive Allele of Schizosaccharomyces pombe mcm4+

PubMed Central

Ranatunga, Nimna S.; Forsburg, Susan L.

2016-01-01

The minichromosome maintenance (MCM) complex is the conserved helicase motor of the eukaryotic replication fork. Mutations in the Mcm4 subunit are associated with replication stress and double strand breaks in multiple systems. In this work, we characterize a new temperature-sensitive allele of Schizosaccharomyces pombe mcm4+. Uniquely among known mcm4 alleles, this mutation causes sensitivity to the alkylation damaging agent methyl methanesulfonate (MMS). Even in the absence of treatment or temperature shift, mcm4-c106 cells show increased repair foci of RPA and Rad52, and require the damage checkpoint for viability, indicating genome stress. The mcm4-c106 mutant is synthetically lethal with mutations disrupting fork protection complex (FPC) proteins Swi1 and Swi3. Surprisingly, we found that the deletion of rif1+ suppressed the MMS-sensitive phenotype without affecting temperature sensitivity. Together, these data suggest that mcm4-c106 destabilizes replisome structure. PMID:27473316

Highly sensitive detection of dipicolinic acid with a water-dispersible terbium-metal organic framework.

PubMed

Bhardwaj, Neha; Bhardwaj, Sanjeev; Mehta, Jyotsana; Kim, Ki-Hyun; Deep, Akash

2016-12-15

The sensitive detection of dipicolinic acid (DPA) is strongly associated with the sensing of bacterial organisms in food and many types of environmental samples. To date, the demand for a sensitive detection method for bacterial toxicity has increased remarkably. Herein, we investigated the DPA detection potential of a water-dispersible terbium-metal organic framework (Tb-MOF) based on the fluorescence quenching mechanism. The Tb-MOF showed a highly sensitive ability to detect DPA at a limit of detection of 0.04nM (linear range of detection: 1nM to 5µM) and also offered enhanced selectivity from other commonly associated organic molecules. The present study provides a basis for the application of Tb-MOF for direct, convenient, highly sensitive, and specific detection of DPA in the actual samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultrasensitive quartz crystal microbalance sensors for detection of M13-Phages in liquids.

PubMed

Uttenthaler, E; Schräml, M; Mandel, J; Drost, S

2001-12-01

Quartz crystal microbalance (QCM) sensors are widely used for determining liquid properties or probing interfacial processes. For some applications the sensitivity of the QCM sensors typically used (5-20 MHz) is limited compared with other biosensor methods. In this study ultrasensitive QCM sensors with resonant frequencies from 39 to 110 MHz for measurements in the liquid phase are presented. The fundamental sensor effect of a QCM is the decrease of the resonant frequency of an oscillating quartz crystal due to the binding of mass on a coated surface during the measurement. The sensitivity of QCM sensors increases strongly with an increasing resonant frequency and, therefore, with a decreasing thickness of the sensitive area. The new kind of ultrasensitive QCM sensors used in this study is based on chemically milled shear mode quartz crystals which are etched only in the center of the blank, forming a thin quartz membrane with a thick, mechanically stable outer ring. An immunoassay using a virus specific monoclonal antibody and a M13-Phage showed an increase in the signal to noise ratio by a factor of more than 6 for 56 MHz quartz crystals compared with standard 19 MHz quartz crystals, the detection limit was improved by a factor of 200. Probing of acoustic properties of glycerol/water mixtures resulted in an increase in sensitivity, which is in very good agreement with theory. Chemically milled QCM sensors strongly improve the sensitivity in biosensing and probing of acoustic properties and, therefore, offer interesting new application fields for QCM sensors.

Photoanode Thickness Optimization and Impedance Spectroscopic Analysis of Dye-Sensitized Solar Cells based on a Carbazole-Containing Ruthenium Dye

NASA Astrophysics Data System (ADS)

Choi, Jongwan; Kim, Felix Sunjoo

2018-03-01

We studied the influence of photoanode thickness on the photovoltaic characteristics and impedance responses of the dye-sensitized solar cells based on a ruthenium dye containing a hexyloxyl-substituted carbazole unit (Ru-HCz). As the thickness of photoanode increases from 4.2 μm to 14.8 μm, the dye-loading amount and the efficiency increase. The device with thicker photoanode shows a decrease in the efficiency due to the higher probability of recombination of electron-hole pairs before charge extraction. We also analyzed the electron-transfer and recombination characteristics as a function of photoanode thickness through detailed electrochemical impedance spectroscopy analysis.

Is Perruchet's dissociation between eyeblink conditioned responding and outcome expectancy evidence for two learning systems?

PubMed

Weidemann, Gabrielle; Tangen, Jason M; Lovibond, Peter F; Mitchell, Christopher J

2009-04-01

P. Perruchet (1985b) showed a double dissociation of conditioned responses (CRs) and expectancy for an airpuff unconditioned stimulus (US) in a 50% partial reinforcement schedule in human eyeblink conditioning. In the Perruchet effect, participants show an increase in CRs and a concurrent decrease in expectancy for the airpuff across runs of reinforced trials; conversely, participants show a decrease in CRs and a concurrent increase in expectancy for the airpuff across runs of nonreinforced trials. Three eyeblink conditioning experiments investigated whether the linear trend in eyeblink CRs in the Perruchet effect is a result of changes in associative strength of the conditioned stimulus (CS), US sensitization, or learning the precise timing of the US. Experiments 1 and 2 demonstrated that the linear trend in eyeblink CRs is not the result of US sensitization. Experiment 3 showed that the linear trend in eyeblink CRs is present with both a fixed and a variable CS-US interval and so is not the result of learning the precise timing of the US. The results are difficult to reconcile with a single learning process model of associative learning in which expectancy mediates CRs. Copyright (c) 2009 APA, all rights reserved.

Pain Perception Is Increased in Congenital but Not Late Onset Blindness

PubMed Central

Slimani, Hocine; Danti, Sabrina; Ptito, Maurice; Kupers, Ron

2014-01-01

There is now ample evidence that blind individuals outperform sighted individuals in various tasks involving the non-visual senses. In line with these results, we recently showed that visual deprivation from birth leads to an increased sensitivity to pain. As many studies have shown that congenitally and late blind individuals show differences in their degree of compensatory plasticity, we here address the question whether late blind individuals also show hypersensitivity to nociceptive stimulation. We therefore compared pain thresholds and responses to supra-threshold nociceptive stimuli in congenitally blind, late blind and normally sighted volunteers. Participants also filled in questionnaires measuring attention and anxiety towards pain in everyday life. Results show that late blind participants have pain thresholds and ratings of supra-threshold heat nociceptive stimuli similar to the normally sighted, whereas congenitally blind participants are hypersensitive to nociceptive thermal stimuli. Furthermore, results of the pain questionnaires did not allow to discriminate late blind from normal sighted participants, whereas congenitally blind individuals had a different pattern of responses. Taken together, these results suggest that enhanced sensitivity to pain following visual deprivation is likely due to neuroplastic changes related to the early loss of vision. PMID:25244529

Characterization of poly methyl methaacrylate and reduced graphene oxide composite for application as electrolyte in dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Shrivatsav, Roshan; Mahalingam, Vignesh; Lakshmi Narayanan, E. R.; Naveen Balaji, N.; Balu, Murali; Krishna Prasad, R.; Kumaresan, Duraisamy

2018-04-01

Quasi-solid state iodide/triiodide redox electrolyte containing reduced graphene oxide and poly (methyl methaacrylate) (RGO-PMMA) composites for the fabrication of more durable, high performance dye sensitized solar cells are prepared. The morphological analysis of prepared RGO-PMMA composites showed formation of spherical like morphologies of RGO dispersed PMMA particles with their macroscopic inter-particle networks having voids. The x ray diffraction and electrical conductivity studies showed the addition of 1 wt% of filler RGO into amorphous PMMA matrix increased the electrical conductivity of the polymer composite about three orders of magnitude from 10‑7 and 10‑4 S cm‑1. Further, the photovoltaic current-voltage analysis of DSSCs with different RGO-PMMA composite based iodide/triiodide redox electrolytes showed the highest power conversion efficiency of 5.38% and the fill factor 0.63 for 2% RGO-PMMA electrolyte. The EIS analysis showed an increased recombination resistance (Rct2) at TiO2 electrode/dye/electrolyte interface due to the better electrical conductivity of RGO with good ionic conductivity in 2% RGO-PMMA composite based redox electrolyte boosted the generation of a high current density and fill factor in their DSSCs.

Hydrological projections of climate change scenarios over the 3H region of China: A VIC model assessment

NASA Astrophysics Data System (ADS)

Dan, Li; Ji, Jinjun; Xie, Zhenghui; Chen, Feng; Wen, Gang; Richey, Jeffrey E.

2012-06-01

To examine the potential sensitivity of the Huang-Huai-Hai Plain (3H) region of China to potential changes in future precipitation and temperature, a hydrological evaluation using the VIC hydrological model under different climate scenarios was carried out. The broader perspective is providing a scientific background for the adaptation in water resource management and rural development to climate change. Twelve climate scenarios were designed to account for possible variations in the future with respect to the baseline of historic climate patterns. Results from the six representative types of climate scenarios (+2°C and +5°C warming, and 0%, +15%, -15% change in precipitation) show that rising temperatures for normal precipitation and for wet scenarios (+15% precipitation) yield greater increased evapotranspiration in the south than in the north, which is confirmed by the remaining six scenarios described below. For a 15% change in precipitation, the largest increase or decrease of evapotranspiration occurs between 33 and 36°N and west of 118°E, a region where evapotranspiration is sensitive to precipitation variation and is affected by the amount of water available for evaporation. Rising temperatures can lead to a south-to-north decreasing gradient of surface runoff. The six scenarios yield a large variation of runoff in the southern end of the 3H, which means that this zone is sensitive to climate change through surface runoff change. The Jiangsu province in the southeastern part of the 3H region shows an obvious sensitivity in soil moisture to climate change. On a regional mean scale, the hydrological change induced by the increasing precipitation from 15% to 30% is more obvious than that induced by greater warming of +5°C relative to +2°C. These simulations identify key regions of sensitivity in hydrological variation to climate change in the provinces of 3H, which can be used as guides in implementing adaptation.

Mechanical Structural Design of a MEMS-Based Piezoresistive Accelerometer for Head Injuries Monitoring: A Computational Analysis by Increments of the Sensor Mass Moment of Inertia †

PubMed Central

Messina, Marco; Njuguna, James; Palas, Chrysovalantis

2018-01-01

This work focuses on the proof-mass mechanical structural design improvement of a tri-axial piezoresistive accelerometer specifically designed for head injuries monitoring where medium-G impacts are common; for example, in sports such as racing cars or American Football. The device requires the highest sensitivity achievable with a single proof-mass approach, and a very low error (<1%) as the accuracy for these types of applications is paramount. The optimization method differs from previous work as it is based on the progressive increment of the sensor proof-mass mass moment of inertia (MMI) in all three axes. Three different designs are presented in this study, where at each step of design evolution, the MMI of the sensor proof-mass gradually increases in all axes. The work numerically demonstrates that an increment of MMI determines an increment of device sensitivity with a simultaneous reduction of cross-axis sensitivity in the particular axis under study. This is due to the linkage between the external applied stress and the distribution of mass (of the proof-mass), and therefore of its mass moment of inertia. Progressively concentrating the mass on the axes where the piezoresistors are located (i.e., x- and y-axis) by increasing the MMI in the x- and y-axis, will undoubtedly increase the longitudinal stresses applied in that areas for a given external acceleration, therefore increasing the piezoresistors fractional resistance change and eventually positively affecting the sensor sensitivity. The final device shows a sensitivity increase of about 80% in the z-axis and a reduction of cross-axis sensitivity of 18% respect to state-of-art sensors available in the literature from a previous work of the authors. Sensor design, modelling, and optimization are presented, concluding the work with results, discussion, and conclusion. PMID:29351221

Stress proteins on the yeast cell surface determine resistance to osmotin, a plant antifungal protein.

PubMed

Yun, D J; Zhao, Y; Pardo, J M; Narasimhan, M L; Damsz, B; Lee, H; Abad, L R; D'Urzo, M P; Hasegawa, P M; Bressan, R A

1997-06-24

Strains of the yeast Saccharomyces cerevisiae differ in their sensitivities to tobacco osmotin, an antifungal protein of the PR-5 family. However, cells sensitive to tobacco osmotin showed resistance to osmotin-like proteins purified from the plant Atriplex nummularia, indicating a strict specificity between the antifungal protein and its target cell. A member of a gene family encoding stress proteins induced by heat and nitrogen limitation, collectively called Pir proteins, was isolated among the genes that conveyed resistance to tobacco osmotin to a susceptible strain. We show that overexpression of Pir proteins increased resistance to osmotin, whereas simultaneous deletion of all PIR genes in a tolerant strain resulted in sensitivity. Pir proteins have been immunolocalized to the cell wall. The enzymatic digestion of the cell wall of sensitive and resistant cells rendered spheroplasts equally susceptible to the cytotoxic action of tobacco osmotin but not to other osmotin-like proteins, indicating that the cell membrane interacts specifically with osmotin and facilitates its action. Our results demonstrate that fungal cell wall proteins are determinants of resistance to antifungal PR-5 proteins.

Stress proteins on the yeast cell surface determine resistance to osmotin, a plant antifungal protein

PubMed Central

Yun, Dae-Jin; Zhao, Yuan; Pardo, José M.; Narasimhan, Meena L.; Damsz, Barbara; Lee, Hyeseung; Abad, Laura R.; D’Urzo, Matilde Paino; Hasegawa, Paul M.; Bressan, Ray A.

1997-01-01

Strains of the yeast Saccharomyces cerevisiae differ in their sensitivities to tobacco osmotin, an antifungal protein of the PR-5 family. However, cells sensitive to tobacco osmotin showed resistance to osmotin-like proteins purified from the plant Atriplex nummularia, indicating a strict specificity between the antifungal protein and its target cell. A member of a gene family encoding stress proteins induced by heat and nitrogen limitation, collectively called Pir proteins, was isolated among the genes that conveyed resistance to tobacco osmotin to a susceptible strain. We show that overexpression of Pir proteins increased resistance to osmotin, whereas simultaneous deletion of all PIR genes in a tolerant strain resulted in sensitivity. Pir proteins have been immunolocalized to the cell wall. The enzymatic digestion of the cell wall of sensitive and resistant cells rendered spheroplasts equally susceptible to the cytotoxic action of tobacco osmotin but not to other osmotin-like proteins, indicating that the cell membrane interacts specifically with osmotin and facilitates its action. Our results demonstrate that fungal cell wall proteins are determinants of resistance to antifungal PR-5 proteins. PMID:9192695

Emotional sensitization highlights the attentional bias in blood-injection-injury phobics: an ERP study.

PubMed

Sarlo, Michela; Buodo, Giulia; Devigili, Andrea; Munafò, Marianna; Palomba, Daniela

2011-02-18

The presence of an attentional bias towards disorder-related stimuli has not been consistently demonstrated in blood phobics. The present study was aimed at investigating whether or not an attentional bias, as measured by event-related potentials (ERPs), could be highlighted in blood phobics by inducing cognitive-emotional sensitization through the repetitive presentation of different disorder-related pictures. The mean amplitudes of the N100, P200, P300 and late positive potentials to picture onset were assessed along with subjective ratings of valence and arousal in 13 blood phobics and 12 healthy controls. Blood phobics, but not controls, showed a linear increase of subjective arousal over time, suggesting that cognitive-emotional sensitization did occur. The analysis of cortical responses showed larger N100 and smaller late positive potentials in phobics than in controls in response to mutilations. These findings suggest that cognitive-emotional sensitization induced an attentional bias in blood phobics during picture viewing, involving early selective encoding and late cognitive avoidance of disorder-related stimuli depicting mutilations. © 2010 Elsevier Ireland Ltd. All rights reserved.

Development of reverse transcription-PCR assays specific for detection of equine encephalitis viruses.

PubMed

Linssen, B; Kinney, R M; Aguilar, P; Russell, K L; Watts, D M; Kaaden, O R; Pfeffer, M

2000-04-01

Specific and sensitive reverse transcription-PCR (RT-PCR) assays were developed for the detection of eastern, western, and Venezuelan equine encephalitis viruses (EEE, WEE, and VEE, respectively). Tests for specificity included all known alphavirus species. The EEE-specific RT-PCR amplified a 464-bp region of the E2 gene exclusively from 10 different EEE strains from South and North America with a sensitivity of about 3,000 RNA molecules. In a subsequent nested PCR, the specificity was confirmed by the amplification of a 262-bp fragment, increasing the sensitivity of this assay to approximately 30 RNA molecules. The RT-PCR for WEE amplified a fragment of 354 bp from as few as 2,000 RNA molecules. Babanki virus, as well as Mucambo and Pixuna viruses (VEE subtypes IIIA and IV), were also amplified. However, the latter viruses showed slightly smaller fragments of about 290 and 310 bp, respectively. A subsequent seminested PCR amplified a 195-bp fragment only from the 10 tested strains of WEE from North and South America, rendering this assay virus specific and increasing its sensitivity to approximately 20 RNA molecules. Because the 12 VEE subtypes showed too much divergence in their 26S RNA nucleotide sequences to detect all of them by the use of nondegenerate primers, this assay was confined to the medically important and closely related VEE subtypes IAB, IC, ID, IE, and II. The RT-PCR-seminested PCR combination specifically amplified 342- and 194-bp fragments of the region covering the 6K gene in VEE. The sensitivity was 20 RNA molecules for subtype IAB virus and 70 RNA molecules for subtype IE virus. In addition to the subtypes mentioned above, three of the enzootic VEE (subtypes IIIB, IIIC, and IV) showed the specific amplicon in the seminested PCR. The practicability of the latter assay was tested with human sera gathered as part of the febrile illness surveillance in the Amazon River Basin of Peru near the city of Iquitos. All of the nine tested VEE-positive sera showed the expected 194-bp amplicon of the VEE-specific RT-PCR-seminested PCR.

Development of a contactless DC current sensor with high linearity and sensitivity based on the magnetoelectric effect

NASA Astrophysics Data System (ADS)

Castro, N.; Reis, S.; Silva, M. P.; Correia, V.; Lanceros-Mendez, S.; Martins, P.

2018-06-01

The magnetoelectric (ME) effect is increasingly being considered an attractive alternative for magnetic field and smart current sensing, being able to sense static and dynamic magnetic fields. This work reports on a contactless DC current sensor device based on a ME PVDF/Metglas composite, a solenoid and the corresponding electronic instrumentation. The ME sample shows a maximum resonant ME coefficient (α 33) of 34.48 V cm‑1 Oe‑1, a linear response (R 2 = 0.998) and a sensitivity of 6.7 mV A‑1. With the incorporation of a charge amplifier, an AC-RMS converter and a microcontroller the linearity is maintained (R 2 = 0.997), the ME output voltage increases to a maximum of 2320 mV and the sensitivity rises to 476.5 mV A‑1. Such features allied to the highest sensitivity reported in the literature on polymer-based ME composites provide to the reported ME sensing device suitable characteristics to be used in non-contact electric current measurement, motor operational status checking, and condition monitoring of rechargeable batteries, among others.

Loss of Selenium-Binding Protein 1 Decreases Sensitivity to Clastogens and Intracellular Selenium Content in HeLa Cells.

PubMed

Zhao, Changhui; Zeng, Huawei; Wu, Ryan T Y; Cheng, Wen-Hsing

2016-01-01

Selenium-binding protein 1 (SBP1) is not a selenoprotein but structurally binds selenium. Loss of SBP1 during carcinogenesis usually predicts poor prognosis. Because genome instability is a hallmark of cancer, we hypothesize that SBP1 sequesters cellular selenium and sensitizes cancer cells to DNA-damaging agents. To test this hypothesis, we knocked down SBP1 expression in HeLa cervical cancer cells by employing a short hairpin RNA (shRNA) approach. Reduced sensitivity to hydrogen peroxide, paraquat and camptothecin, reactive oxygen species content, and intracellular retention of selenium after selenomethionine treatment were observed in SBP1 shRNA HeLa cells. Results from Western analyses showed that treatment of HeLa cells with selenomethionine resulted in increased SBP1 protein expression in a dose-dependent manner. Knockdown of SBP1 rendered HeLa cells increased expression of glutathione peroxidase-1 but not glutathione peroxidase-4 protein levels and accelerated migration from a wound. Altogether, SBP1 retains supplemental selenium and sensitizes HeLa cancer cells to clastogens, suggesting a new cancer treatment strategy by sequestering selenium through SBP1.

Isolation and characterization of OmpC porin mutants with altered pore properties

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

Misra, R.; Benson, S.A.

1988-02-01

The LamB protien is normally required for the uptake of maltodextrins. Starting with a LamB/sup -/ OmpF/sup -/ strain, we have isolated mutants that will grow on maltodextrins. The mutation conferring the Dex/sup +/ phenotype in the majority of these mutants has been mapped to the ompC locus. These mutants, unlike LamB/sup -/ OmpF/sup -/ strains, grew on maltotriose and maltotetraose, but not on maltopentaose, and showed a significantly higher rate of (/sup 14/C) maltose uptake than the parent strain did. In addition, these mutants showed increased sensitivity to certain ..beta..-lactam antibiotics and sodium dodecyl sulfate, but did not exhibitmore » an increase in sensitivity to other antibiotics and detergents. The nucleotide sequence of these mutants has been determined. In all cases, residue 74 (arginine) of the mature OmpC protein was affected. The results suggest that this region of the OmpC protein is involved in the pore domain and that the alterations lead to an increased pore size.« less

DRP1 Suppresses Leptin and Glucose Sensing of POMC Neurons.

PubMed

Santoro, Anna; Campolo, Michela; Liu, Chen; Sesaki, Hiromi; Meli, Rosaria; Liu, Zhong-Wu; Kim, Jung Dae; Diano, Sabrina

2017-03-07

Hypothalamic pro-opiomelanocortin (POMC) neurons regulate energy and glucose metabolism. Intracellular mechanisms that enable these neurons to respond to changes in metabolic environment are ill defined. Here we show reduced expression of activated dynamin-related protein (pDRP1), a mitochondrial fission regulator, in POMC neurons of fed mice. These POMC neurons displayed increased mitochondrial size and aspect ratio compared to POMC neurons of fasted animals. Inducible deletion of DRP1 of mature POMC neurons (Drp1 fl/fl -POMC-cre:ER T2 ) resulted in improved leptin sensitivity and glucose responsiveness. In Drp1 fl/fl -POMC-cre:ER T2 mice, POMC neurons showed increased mitochondrial size, ROS production, and neuronal activation with increased expression of Kcnj11 mRNA regulated by peroxisome proliferator-activated receptor (PPAR). Furthermore, deletion of DRP1 enhanced the glucoprivic stimulus in these neurons, causing their stronger inhibition and a greater activation of counter-regulatory responses to hypoglycemia that were PPAR dependent. Together, these data unmasked a role for mitochondrial fission in leptin sensitivity and glucose sensing of POMC neurons. Copyright © 2017 Elsevier Inc. All rights reserved.

High Throughput Measurement of Locomotor Sensitization to Volatilized Cocaine in Drosophila melanogaster.

PubMed

Filošević, Ana; Al-Samarai, Sabina; Andretić Waldowski, Rozi

2018-01-01

Drosophila melanogaster can be used to identify genes with novel functional roles in neuronal plasticity induced by repeated consumption of addictive drugs. Behavioral sensitization is a relatively simple behavioral output of plastic changes that occur in the brain after repeated exposures to drugs of abuse. The development of screening procedures for genes that control behavioral sensitization has stalled due to a lack of high-throughput behavioral tests that can be used in genetically tractable organism, such as Drosophila . We have developed a new behavioral test, FlyBong, which combines delivery of volatilized cocaine (vCOC) to individually housed flies with objective quantification of their locomotor activity. There are two main advantages of FlyBong: it is high-throughput and it allows for comparisons of locomotor activity of individual flies before and after single or multiple exposures. At the population level, exposure to vCOC leads to transient and concentration-dependent increase in locomotor activity, representing sensitivity to an acute dose. A second exposure leads to further increase in locomotion, representing locomotor sensitization. We validate FlyBong by showing that locomotor sensitization at either the population or individual level is absent in the mutants for circadian genes period (per) , Clock (Clk) , and cycle (cyc) . The locomotor sensitization that is present in timeless (tim) and pigment dispersing factor (pdf) mutant flies is in large part not cocaine specific, but derived from increased sensitivity to warm air. Circadian genes are not only integral part of the neural mechanism that is required for development of locomotor sensitization, but in addition, they modulate the intensity of locomotor sensitization as a function of the time of day. Motor-activating effects of cocaine are sexually dimorphic and require a functional dopaminergic transporter. FlyBong is a new and improved method for inducing and measuring locomotor sensitization to cocaine in individual Drosophila . Because of its high-throughput nature, FlyBong can be used in genetic screens or in selection experiments aimed at the unbiased identification of functional genes involved in acute or chronic effects of volatilized psychoactive substances.

High Throughput Measurement of Locomotor Sensitization to Volatilized Cocaine in Drosophila melanogaster

PubMed Central

Filošević, Ana; Al-samarai, Sabina; Andretić Waldowski, Rozi

2018-01-01

Drosophila melanogaster can be used to identify genes with novel functional roles in neuronal plasticity induced by repeated consumption of addictive drugs. Behavioral sensitization is a relatively simple behavioral output of plastic changes that occur in the brain after repeated exposures to drugs of abuse. The development of screening procedures for genes that control behavioral sensitization has stalled due to a lack of high-throughput behavioral tests that can be used in genetically tractable organism, such as Drosophila. We have developed a new behavioral test, FlyBong, which combines delivery of volatilized cocaine (vCOC) to individually housed flies with objective quantification of their locomotor activity. There are two main advantages of FlyBong: it is high-throughput and it allows for comparisons of locomotor activity of individual flies before and after single or multiple exposures. At the population level, exposure to vCOC leads to transient and concentration-dependent increase in locomotor activity, representing sensitivity to an acute dose. A second exposure leads to further increase in locomotion, representing locomotor sensitization. We validate FlyBong by showing that locomotor sensitization at either the population or individual level is absent in the mutants for circadian genes period (per), Clock (Clk), and cycle (cyc). The locomotor sensitization that is present in timeless (tim) and pigment dispersing factor (pdf) mutant flies is in large part not cocaine specific, but derived from increased sensitivity to warm air. Circadian genes are not only integral part of the neural mechanism that is required for development of locomotor sensitization, but in addition, they modulate the intensity of locomotor sensitization as a function of the time of day. Motor-activating effects of cocaine are sexually dimorphic and require a functional dopaminergic transporter. FlyBong is a new and improved method for inducing and measuring locomotor sensitization to cocaine in individual Drosophila. Because of its high-throughput nature, FlyBong can be used in genetic screens or in selection experiments aimed at the unbiased identification of functional genes involved in acute or chronic effects of volatilized psychoactive substances. PMID:29459820

Cocaine sensitization models an anhedonia-like condition in rats.

PubMed

Scheggi, Simona; Marchese, Giovanna; Grappi, Silvia; Secci, Maria Elena; De Montis, Maria Graziella; Gambarana, Carla

2011-04-01

Anhedonia is a core symptom of depression that also characterizes substance abuse-related mood disorders, in particular those secondary to stimulant abuse. This study investigated the long-lasting condition of cocaine sensitization as an inducing condition for anhedonia in rats. Cortical-mesolimbic dopamine plays a central role in assessing the incentive value of a stimulus and an increased dopamine output in these areas after a novel palatable meal seems to correlate with the ability to acquire an instrumental behaviour aimed at earning it again. This dopaminergic response is associated with consistent modifications in the phosphorylation pattern of some cAMP-dependent protein kinase (PKA) substrates and it is mediated by dopamine D1 receptor stimulation. Thus, since behavioural cocaine sensitization is characterized by tonically increased levels of phospho-Thr75 DARPP-32 that is a potent PKA inhibitor, we hypothesized that cocaine-sensitized rats might reveal deficits in palatable food responding. Indeed, non-food-deprived cocaine-sensitized rats showed no interest in palatable food, no dopaminergic response after a palatable meal in terms of increased dopamine output and DARPP-32 phosphorylation changes, and no ability to acquire a palatable food-sustained instrumental behaviour. Repeated administration of an established antidepressant compound, imipramine, corrected these deficits and reinstated the dopaminergic response in the cortico-mesolimbic areas to control values. Thus, the behavioural modifications observed in cocaine-sensitized rats satisfy some requirements for an experimental model of anhedonia since they are induced by repeated cocaine administration (aetiological validity), they mimic an anhedonia-like symptom (construct validity), and are reversed by the administration of imipramine (predictive validity).

Comparative viability of unirradiated and gamma irradiated bacterial cells

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

Maxcy, R.B.

1977-01-01

Gamma radiation injured Escherichia coli, Salmonella typhimurium, and Moraxella sp. were studied under various environmental stresses to determine their fate relative to the parent population. Irradiated cultures formed smaller colonies on surface plates with fewer cells per colony. Unirradiated cultures had a shorter lag phase than irradiated cultures in broth and duration of lag increased as a result of increasing the radiation dose. Repeated irradiation and subculture progressively retarded growth rate. Multiple radiation of highly resistant Moraxella sp. showed radiation injured cells to be more sensitive than uninjured cells. With the three species studied, irradiation raised the lower limits ofmore » growth temperature, increased the sensitivity to freezing and thawing, and increased the susceptibility to lowered water activity. This work indicated that the production of a bizarre, resistant strain of bacteria through recycling in a food processing operation is highly unlikely.« less

Induction of dyspnea evokes increased anxiety and maladaptive breathing in individuals with high anxiety sensitivity and suffocation fear.

PubMed

Alius, Manuela G; Pané-Farré, Christiane A; Von Leupoldt, Andreas; Hamm, Alfons O

2013-05-01

Although respiratory symptoms are relevant for diagnosis and etiology of panic disorder, anxiety responses and breathing behavior evoked by induction of dyspnea have rarely been studied. Therefore, dyspnea sensations and affective evaluations evoked by inspiratory resistive loads of different intensities were first assessed in 23 individuals with high versus 24 participants with low anxiety sensitivity (AS). High AS participants with high fear of suffocation rated loads of the same physical intensity as more unpleasant and reported more intense feelings of dyspnea and more respiratory and panic symptoms than low AS individuals. In the second experiment assessing physiological responses to physically comparable loads, high suffocation fear participants showed an increase in minute ventilation to compensate for fear-induced air hunger. This ventilation behavior results in increased frequency of dyspnea sensations, thus increasing fear of suffocation. Copyright © 2013 Society for Psychophysiological Research.

Adolescent C57BL/6J mice show elevated alcohol intake, but reduced taste aversion, as compared to adult mice: a potential behavioral mechanism for binge drinking.

PubMed

Holstein, Sarah E; Spanos, Marina; Hodge, Clyde W

2011-10-01

Binge alcohol drinking during adolescence is a serious health problem that may increase future risk of an alcohol use disorder. Although there are several different procedures by which to preclinically model binge-like alcohol intake, limited-access procedures offer the advantage of achieving high voluntary alcohol intake and pharmacologically relevant blood alcohol concentrations (BACs). Therefore, in the current study, developmental differences in binge-like alcohol drinking using a limited-access cycling procedure were examined. In addition, as alcohol drinking has been negatively correlated with sensitivity to the aversive properties of alcohol, we examined developmental differences in sensitivity to an alcohol-induced conditioned taste aversion (CTA). Binge-like alcohol consumption was investigated in adolescent (4 weeks) and adult (10 weeks) male C57BL/6J mice for 2 to 4 h/d for 16 days. Developmental differences in sensitivity to an alcohol-induced CTA were examined in adolescent and adult mice, with saline or alcohol (3 or 4 g/kg) repeatedly paired with the intake of a novel tastant (NaCl). Adolescent mice showed a significant increase in alcohol intake as compared to adults, with adolescents achieving higher BACs and increasing alcohol consumption over successive cycles of the binge procedure. Conversely, adolescent mice exhibited a dose-dependent reduction in sensitivity to the aversive properties of alcohol, as compared to adult mice, with adolescent mice failing to develop a CTA to 3 g/kg alcohol. Finally, extinction of an alcohol CTA was observed following conditioning with a higher dose of alcohol in adolescent, versus adult, mice. These results indicate that adolescent mice consume more alcohol, per kilogram body weight, than adults in a binge-like model of alcohol drinking and demonstrate a blunted sensitivity to the conditioned aversive effects of alcohol. Overall, this supports a behavioral framework by which heightened binge alcohol intake during adolescence occurs, in part, via a reduced sensitivity to the aversive properties of alcohol. Copyright © 2011 by the Research Society on Alcoholism.

Adolescent C57BL/6J mice show elevated alcohol intake, but reduced taste aversion, as compared to adult mice: a potential behavioral mechanism for binge drinking

PubMed Central

Holstein, Sarah E.; Spanos, Marina; Hodge, Clyde W.

2011-01-01

Background Binge alcohol drinking during adolescence is a serious health problem which may increase future risk of an alcohol use disorder. Although there are several different procedures by which to preclinically model binge-like alcohol intake, limited-access procedures offer the advantage of achieving high voluntary alcohol intake and pharmacologically relevant blood alcohol concentrations (BACs). Therefore, in the current study, developmental differences in binge-like alcohol drinking using a limited-access cycling procedure were examined. In addition, as alcohol drinking has been negatively correlated with sensitivity to the aversive properties of alcohol, we examined developmental differences in sensitivity to an alcohol-induced conditioned taste aversion (CTA). Methods Binge-like alcohol consumption was investigated in adolescent (4 wk) and adult (10 wk) male C57BL/6J mice for 2-4 h/day for 16 d. Developmental differences in sensitivity to an alcohol-induced CTA were examined in adolescent and adult mice, with saline or alcohol (3 or 4 g/kg) repeatedly paired with intake of a novel tastant (NaCl). Results Adolescent mice showed a significant increase in alcohol intake as compared to adults, with adolescents achieving higher BACs and increasing alcohol consumption over successive cycles of the binge procedure. Conversely, adolescent mice exhibited a dose-dependent reduction in sensitivity to the aversive properties of alcohol, as compared to adult mice, with adolescent mice failing to develop a CTA to 3 g/kg alcohol. Finally, extinction of an alcohol CTA was observed following conditioning with a higher dose of alcohol in adolescent, versus adult, mice. Conclusions These results indicate that adolescent mice consume more alcohol, per kg body weight, than adults in a binge-like model of alcohol drinking, and demonstrate a blunted sensitivity to the conditioned aversive effects of alcohol. Overall, this supports a behavioral framework by which heightened binge alcohol intake during adolescence occurs, in part, via a reduced sensitivity to the aversive properties of alcohol. PMID:21575017

Species composition and forest structure explain the temperature sensitivity patterns of productivity in temperate forests

NASA Astrophysics Data System (ADS)

Bohn, Friedrich J.; May, Felix; Huth, Andreas

2018-03-01

Rising temperatures due to climate change influence the wood production of forests. Observations show that some temperate forests increase their productivity, whereas others reduce their productivity. This study focuses on how species composition and forest structure properties influence the temperature sensitivity of aboveground wood production (AWP). It further investigates which forests will increase their productivity the most with rising temperatures. We described forest structure by leaf area index, forest height and tree height heterogeneity. Species composition was described by a functional diversity index (Rao's Q) and a species distribution index (ΩAWP). ΩAWP quantified how well species are distributed over the different forest layers with regard to AWP. We analysed 370 170 forest stands generated with a forest gap model. These forest stands covered a wide range of possible forest types. For each stand, we estimated annual aboveground wood production and performed a climate sensitivity analysis based on 320 different climate time series (of 1-year length). The scenarios differed in mean annual temperature and annual temperature amplitude. Temperature sensitivity of wood production was quantified as the relative change in productivity resulting from a 1 °C rise in mean annual temperature or annual temperature amplitude. Increasing ΩAWP positively influenced both temperature sensitivity indices of forest, whereas forest height showed a bell-shaped relationship with both indices. Further, we found forests in each successional stage that are positively affected by temperature rise. For such forests, large ΩAWP values were important. In the case of young forests, low functional diversity and small tree height heterogeneity were associated with a positive effect of temperature on wood production. During later successional stages, higher species diversity and larger tree height heterogeneity were an advantage. To achieve such a development, one could plant below the closed canopy of even-aged, pioneer trees a climax-species-rich understorey that will build the canopy of the mature forest. This study highlights that forest structure and species composition are both relevant for understanding the temperature sensitivity of wood production.

[Astragalus polysaccharide may increase sensitivity of cervical cancer HeLa cells to cisplatin by regulating cell autophagy].

PubMed

Zhai, Qiu-Li; Hu, Xiang-Dan; Xiao, Jing; Yu, Dong-Qing

2018-02-01

This study aimed to investigate the possible sensitivity of Astragalus polysaccharides, in order to improve the chemosensitivity of cervical cancer HeLa cells to cisplatin by regulating the cell autophagy, and explore its possible mechanism. In this study, HeLa cells were divided into control group, cisplatin group, Astragalus polysaccharide group, and Astragalus polysaccharide combined with cisplatin group. MTT assay was used to detect the proliferation of cervical cancer HeLa cells. Flow cytometry was used to detect the apoptosis and cycle of HeLa cells in each experimental group. RT-PCR was used to detect the mRNA expression of autophagy-related proteins beclin1, LC3Ⅱ and p62. The expression levels of autophagy-related proteins beclin1, LC3Ⅱ, LC3Ⅰ and p62 were detected by WB method. MTT results showed that compared with the control group, the proliferation of HeLa cells was significantly inhibited in each administration group( P <0.05), and the inhibitory effect of the combination group was more significant( P <0.01). The apoptotic rate of HeLa cells was significantly increased( P <0.05), and the apoptotic rate of the combination group was significantly increased( P <0.01) compared with the control group( P <0.05).In conclusion, G₀/G₁ phase showed the most significant differences between the two groups. RT-PCR and WB results showed that the gene and protein expressions of beclin1 and LC3Ⅱ were up-regulated, while the gene and protein expressions of p62 were down-regulated compared with the control group. The above-mentioned changes in the combination group were more significant. Through the analysis of the above experimental results, it is speculated that Astragalus polysaccharides may increase the sensitivity of cervical cancer HeLa cells to cisplatin by regulating the cell autophagy. Its possible mechanism of action is correlated with the up-regulation of autophagy-related proteins beclin1, the promote the conversion from LC3Ⅰ to LC3Ⅱ, the down-regulation of labeled protein p62, and the enhancement of HeLa cell autophagic activity, thereby increasing the sensitivity of HeLa cells to cisplatin chemotherapy. Copyright© by the Chinese Pharmaceutical Association.

PCR Inhibition of a Quantitative PCR for Detection of Mycobacterium avium Subspecies Paratuberculosis DNA in Feces: Diagnostic Implications and Potential Solutions

PubMed Central

Acharya, Kamal R.; Dhand, Navneet K.; Whittington, Richard J.; Plain, Karren M.

2017-01-01

Molecular tests such as polymerase chain reaction (PCR) are increasingly being applied for the diagnosis of Johne’s disease, a chronic intestinal infection of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). Feces, as the primary test sample, presents challenges in terms of effective DNA isolation, with potential for PCR inhibition and ultimately for reduced analytical and diagnostic sensitivity. However, limited evidence is available regarding the magnitude and diagnostic implications of PCR inhibition for the detection of MAP in feces. This study aimed to investigate the presence and diagnostic implications of PCR inhibition in a quantitative PCR assay for MAP (High-throughput Johne’s test) to investigate the characteristics of samples prone to inhibition and to identify measures that can be taken to overcome this. In a study of fecal samples derived from a high prevalence, endemically infected cattle herd, 19.94% of fecal DNA extracts showed some evidence of inhibition. Relief of inhibition by a five-fold dilution of the DNA extract led to an average increase in quantification of DNA by 3.3-fold that consequently increased test sensitivity of the qPCR from 55 to 80% compared to fecal culture. DNA extracts with higher DNA and protein content had 19.33 and 10.94 times higher odds of showing inhibition, respectively. The results suggest that the current test protocol is sensitive for herd level diagnosis of Johne’s disease but that test sensitivity and individual level diagnosis could be enhanced by relief of PCR inhibition, achieved by five-fold dilution of the DNA extract. Furthermore, qualitative and quantitative parameters derived from absorbance measures of DNA extracts could be useful for prediction of inhibitory fecal samples. PMID:28210245

Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

NASA Astrophysics Data System (ADS)

Strada, Susanna; Unger, Nadine

2016-04-01

A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP) and isoprene emission. The impacts of different pollution aerosol sources (anthropogenic, biomass burning, and non-biomass burning) are investigated by performing sensitivity experiments. The model framework includes all known light and meteorological responses of photosynthesis, but uses fixed canopy structures and phenology. On a global scale, our results show that global land carbon fluxes (GPP and isoprene emission) are not sensitive to pollution aerosols, even under a global decline in surface solar radiation (direct + diffuse) by ˜ 9 %. At a regional scale, GPP and isoprene emission show a robust but opposite sensitivity to pollution aerosols in regions where forested canopies dominate. In eastern North America and Eurasia, anthropogenic pollution aerosols (mainly from non-biomass burning sources) enhance GPP by +5-8 % on an annual average. In the northwestern Amazon Basin and central Africa, biomass burning aerosols increase GPP by +2-5 % on an annual average, with a peak in the northwestern Amazon Basin during the dry-fire season (+5-8 %). The prevailing mechanism varies across regions: light scattering dominates in eastern North America, while a reduction in direct radiation dominates in Europe and China. Aerosol-induced GPP productivity increases in the Amazon and central Africa include an additional positive feedback from reduced canopy temperatures in response to increases in canopy conductance. In Eurasia and northeastern China, anthropogenic pollution aerosols drive a decrease in isoprene emission of -2 to -12 % on an annual average. Future research needs to incorporate the indirect effects of aerosols and possible feedbacks from dynamic carbon allocation and phenology.

OSL and thermally assisted OSL response in dental enamel for its possible application in retrospective dosimetry.

PubMed

Soni, Anuj; Mishra, D R; Polymeris, G S; Bhatt, B C; Kulkarni, M S

2014-11-01

Dental enamel was studied for its thermoluminescence (TL) and optically stimulated luminescence (OSL) defects. The TL studies showed a wide glow curve with multiple peaks. The thermally assisted OSL (TA-OSL) studies showed that the integrated TA-OSL and thus OSL signal increases with readout temperature between 100 and 250 °C, due to the temperature dependence of OSL. The thermally assisted energy E A associated with this increase is found to be 0.21 ± 0.015 eV. On the other hand, the signal intensity decreases with temperature between 260 and 450 °C. This decrease could be due to depletion of OSL active traps or possible thermal quenching. The increase of the OSL signal at increased temperature can be used to enhance the sensitivity of dental enamel for ex vivo measurements in retrospective dosimetry. The emission and excitation spectra of its luminescence centers were studied by photoluminescence and were found to be at 412 and 324 nm, respectively. It was found to possess multiple OSL active traps having closely lying photoionization cross sections characterized by continuous wave OSL and nonlinear OSL methods. The investigated dental enamel samples showed a linear OSL dose response up to 500 Gy. The dose threshold was found to be 100 mGy using a highly sensitive compact OSL reader with blue LED (470 nm) stimulation.

Prenatal Exposure to the Environmental Obesogen Tributyltin Predisposes Multipotent Stem Cells to Become Adipocytes

PubMed Central

Kirchner, Séverine; Kieu, Tiffany; Chow, Connie; Casey, Stephanie; Blumberg, Bruce

2010-01-01

The environmental obesogen hypothesis proposes that pre- and postnatal exposure to environmental chemicals contributes to adipogenesis and the development of obesity. Tributyltin (TBT) is an agonist of both retinoid X receptor (RXR) and peroxisome proliferator-activated receptor γ (PPARγ). Activation of these receptors can elevate adipose mass in adult mice exposed to the chemical in utero. Here we show that TBT sensitizes human and mouse multipotent stromal stem cells derived from white adipose tissue [adipose-derived stromal stem cells (ADSCs)] to undergo adipogenesis. In vitro exposure to TBT, or the PPARγ activator rosiglitazone increases adipogenesis, cellular lipid content, and expression of adipogenic genes. The adipogenic effects of TBT and rosiglitazone were blocked by the addition of PPARγ antagonists, suggesting that activation of PPARγ mediates the effect of both compounds on adipogenesis. ADSCs from mice exposed to TBT in utero showed increased adipogenic capacity and reduced osteogenic capacity with enhanced lipid accumulation in response to adipogenic induction. ADSCs retrieved from animals exposed to TBT in utero showed increased expression of PPARγ target genes such as the early adipogenic differentiation gene marker fatty acid-binding protein 4 and hypomethylation of the promoter/enhancer region of the fatty acid-binding protein 4 locus. Hence, TBT alters the stem cell compartment by sensitizing multipotent stromal stem cells to differentiate into adipocytes, an effect that could likely increase adipose mass over time. PMID:20160124

Prenatal exposure to the environmental obesogen tributyltin predisposes multipotent stem cells to become adipocytes.

PubMed

Kirchner, Séverine; Kieu, Tiffany; Chow, Connie; Casey, Stephanie; Blumberg, Bruce

2010-03-01

The environmental obesogen hypothesis proposes that pre- and postnatal exposure to environmental chemicals contributes to adipogenesis and the development of obesity. Tributyltin (TBT) is an agonist of both retinoid X receptor (RXR) and peroxisome proliferator-activated receptor gamma (PPARgamma). Activation of these receptors can elevate adipose mass in adult mice exposed to the chemical in utero. Here we show that TBT sensitizes human and mouse multipotent stromal stem cells derived from white adipose tissue [adipose-derived stromal stem cells (ADSCs)] to undergo adipogenesis. In vitro exposure to TBT, or the PPARgamma activator rosiglitazone increases adipogenesis, cellular lipid content, and expression of adipogenic genes. The adipogenic effects of TBT and rosiglitazone were blocked by the addition of PPARgamma antagonists, suggesting that activation of PPARgamma mediates the effect of both compounds on adipogenesis. ADSCs from mice exposed to TBT in utero showed increased adipogenic capacity and reduced osteogenic capacity with enhanced lipid accumulation in response to adipogenic induction. ADSCs retrieved from animals exposed to TBT in utero showed increased expression of PPARgamma target genes such as the early adipogenic differentiation gene marker fatty acid-binding protein 4 and hypomethylation of the promoter/enhancer region of the fatty acid-binding protein 4 locus. Hence, TBT alters the stem cell compartment by sensitizing multipotent stromal stem cells to differentiate into adipocytes, an effect that could likely increase adipose mass over time.

Sensitivity to nitrate and nitrite in pond-breeding amphibians from the Pacific Northwest, USA

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

Marco, A.; Quilchano, C.; Blaustein, A.R.

1999-12-01

In static experiments, the authors studied the effects of nitrate and nitrate solutions on newly hatched larvae of five species of amphibians, namely Rana pretiosa, Rana aurora, Bufo boreas, Hyla regilla, and Ambystoma gracile. When nitrate or nitrite ions were added to the water, some larvae of some species reduced feeding activity, swam less vigorously, showed disequilibrium and paralysis, suffered abnormalities and edemas, and eventually died. The observed effects increased with both concentration and time, and there were significant differences in sensitivity among species. Ambrystoma gracile displayed the highest acute effect in water with nitrate and nitrite. The three ranidmore » species had acute effects in water with nitrite. In chronic exposures, R. pretiosa was the most sensitive species to nitrates and nitrites. All species showed 15-d LC50s lower than 2 mg N-NO{sub 2{sup {minus}}}/L. For both N ions, B. boreas was the least sensitive amphibian. All species showed a high morality at the US Environmental Protection Agency-recommended limits of nitrite for warm-water fishes and a significant larval mortality at the recommended limits of nitrite concentration for drinking water. The recommended levels of nitrate for warm-water fishes were highly toxic for R. pretiosa and A. gracile larvae.« less

Molecularly Engineered Ru(II) Sensitizers Compatible with Cobalt(II/III) Redox Mediators for Dye-Sensitized Solar Cells.

PubMed

Wu, Kuan-Lin; Huckaba, Aron J; Clifford, John N; Yang, Ya-Wen; Yella, Aswani; Palomares, Emilio; Grätzel, Michael; Chi, Yun; Nazeeruddin, Mohammad Khaja

2016-08-01

Thiocyanate-free isoquinazolylpyrazolate Ru(II) complexes were synthesized and applied as sensitizers in dye-sensitized solar cells (DSCs). Unlike most other successful Ru sensitizers, Co-based electrolytes were used, and resulting record efficiency of 9.53% was obtained under simulated sunlight with an intensity of 100 mW cm(-2). Specifically, dye 51-57dht.1 and an electrolyte based on Co(phen)3 led to measurement of a JSC of 13.89 mA cm(-2), VOC of 900 mV, and FF of 0.762 to yield 9.53% efficiency. The improved device performances were achieved by the inclusion of 2-hexylthiophene units onto the isoquinoline subunits, in addition to lengthening the perfluoroalkyl chain on the pyrazolate chelating group, which worked to increase light absorption and decrease recombination effects when using the Co-based electrolyte. As this study shows, Ru(II) sensitizers bearing sterically demanding ligands can allow successful utilization of important Co electrolytes and high performance.

Perinatal maternal stress and serotonin signaling: effects on pain sensitivity in offspring.

PubMed

Knaepen, Liesbeth; Pawluski, Jodi L; Patijn, Jacob; van Kleef, Maarten; Tibboel, Dick; Joosten, Elbert A

2014-07-01

It has been estimated that 20% of pregnant women are facing perinatal stress and depression. Perinatal maternal stress has been shown to increase pain sensitivity in offspring. For the treatment of their depressive symptoms, pregnant women are frequently prescribed selective serotonin reuptake inhibitors (SSRIs). Since the descending pain inhibitory circuit matures perinatally, perinatal SSRI exposure has been shown to affect pain sensitivity in offspring. In the present review, we summarize experimental and clinical evidence for the effect of perinatal maternal stress and SSRI exposure on pain sensitivity in offspring. Both experimental and clinical studies show the effect of perinatal maternal stress on regulation of the hypothalamic-pituitary-adrenal (HPA) system and the serotonin pain inhibitory system. Alterations in these two systems likely underlie long-term alterations in the development of pain sensitivity. This review sheds light on the effect of perinatal maternal stress and treatment with SSRIs on offspring pain sensitivity, in relation to the developing HPA system and 5-HT signaling. © 2013 Wiley Periodicals, Inc.

Thin films composed of multiwalled carbon nanotubes, gold nanoparticles and myoglobin for humidity detection at room temperature.

PubMed

Qi, Zhi-mei; Wei, Mingdeng; Honma, Itaru; Zhou, Haoshen

2007-02-02

Optically transparent and electrically conductive nanocomposite thin films consisting of multiwalled carbon nanotubes (MWCNTs), gold nanoparticles (GNPs) and myoglobin molecules that glue GNPs and MWCNTs together are fabricated for the first time on glass substrates from aqueous solution. The nanocomposite thin film is capable of varying its resistance, impedance or optical transmittance at room temperature in response to changes in ambient humidity. The conductometric sensitivity to relative humidity (RH) of the nanocomposite thin film is compared with those of the pure and Mb-functionalized MWCNT layers. The pure MWCNT layer shows a small increase in its resistance with increasing RH due to the effect of p-type semiconducting nanotubes present in the film. In contrast, a four times higher sensitivity to RH is observed for both the nanocomposite and Mb-functionalized MWCNT thin films. The sensitivity enhancement is attributable to swelling of the thin films induced by water absorption in the presence of Mb molecules, which increases the inter-nanotube spacing and thereby causes a further increase of the film resistance. A humidity change as low as DeltaRH=0.3 % has been readily detected by conductometry using the nanocomposite thin film.

Sensitivity to bites by the bedbug, Cimex lectularius.

PubMed

Reinhardt, K; Kempke, D; Naylor, R A; Siva-Jothy, M T

2009-06-01

Bedbugs are a public health problem and can cause significant economic losses, but little is known about the effects of bites on humans. We reviewed case reports and published papers on bedbug bites to assess the empirical basis of the commonly cited figure that only approximately 80% of the population are sensitive to bedbug bites. We found the sensitivity estimate to be based on only one study carried out 80 years ago. However, this study did not account for the now well-established fact that only repeated exposure to external allergens leads to skin reactions. In our sample, 18 of 19 persons showed a skin reaction after bedbug exposure, but in most cases only after repeated controlled exposure. With repeated exposure, the latency between bite and skin reactions decreased from approximately 10 days to a few seconds. Our results are relevant for the hospitality industry, where apparently increasing infestation rates are likely to lead to an increase in the number of tourists and hotel employees exposed to bedbugs. Medical and public health professionals may expect to see an increase in the prevalence of people with bedbug bite sensitivity. The significance of the delayed reaction time of skin to bites may also have implications in litigation cases where people seek compensation.

Sensitivity Changes over the Course of Infection Increases the Likelihood of Resistance Against Fusion but Not CCR5 Receptor Blockers

PubMed Central

Chatziandreou, Nikolaos; Arauz, Ana Belen; Freitas, Ines; Nyein, Phyu Hninn; Fenton, Gregory; Mehta, Shruti H.; Kirk, Gregory D.

2012-01-01

Abstract As HIV-1 evolves over the course of infection, resistance against antiretrovirals may arise in the absence of drug pressure, especially against receptor and fusion blockers because of the extensive changes observed in the envelope glycoprotein. Here we show that viruses from the chronic phase of disease are significantly less sensitive to CCR5 receptor and fusion blockers compared to early infection variants. Differences in susceptibility to CCR5 antagonists were observed in spite of no demonstrable CXCR4 receptor utilization. No significant sensitivity differences were observed to another entry blocker, soluble CD4, or to reverse transcriptase, protease, or integrase inhibitors. Chronic as compared to early phase variants demonstrated greater replication when passaged in the presence of subinhibitory concentrations of fusion but not CCR5 receptor inhibitors. Fusion antagonist resistance, however, emerged from only one chronic phase virus culture. Because sensitivity to receptor and fusion antagonists is correlated with receptor affinity and fusion capacity, respectively, changes that occur in the envelope glycoprotein over the course of infection confer greater ability to use the CCR5 receptor and increased fusion ability. Our in vitro passage studies suggest that these evolving phenotypes increase the likelihood of resistance against fusion but not CCR5 receptor blockers. PMID:22650962

Increased imaging speed and force sensitivity for bio-applications with small cantilevers using a conventional AFM setup

PubMed Central

Leitner, Michael; Fantner, Georg E.; Fantner, Ernest J.; Ivanova, Katerina; Ivanov, Tzvetan; Rangelow, Ivo; Ebner, Andreas; Rangl, Martina; Tang, Jilin; Hinterdorfer, Peter

2012-01-01

In this study, we demonstrate the increased performance in speed and sensitivity achieved by the use of small AFM cantilevers on a standard AFM system. For this, small rectangular silicon oxynitride cantilevers were utilized to arrive at faster atomic force microscopy (AFM) imaging times and more sensitive molecular recognition force spectroscopy (MRFS) experiments. The cantilevers we used had lengths between 13 and 46 μm, a width of about 11 μm, and a thickness between 150 and 600 nm. They were coated with chromium and gold on the backside for a better laser reflection. We characterized these small cantilevers through their frequency spectrum and with electron microscopy. Due to their small size and high resonance frequency we were able to increase the imaging speed by a factor of 10 without any loss in resolution for images from several μm scansize down to the nanometer scale. This was shown on bacterial surface layers (s-layer) with tapping mode under aqueous, near physiological conditions and on nuclear membranes in contact mode in ambient environment. In addition, we showed that single molecular forces can be measured with an up to 5 times higher force sensitivity in comparison to conventional cantilevers with similar spring constants. PMID:22721963

Validation of diffuse correlation spectroscopy sensitivity to nicotinamide-induced blood flow elevation in the murine hindlimb using the fluorescent microsphere technique

NASA Astrophysics Data System (ADS)

Proctor, Ashley R.; Ramirez, Gabriel A.; Han, Songfeng; Liu, Ziping; Bubel, Tracy M.; Choe, Regine

2018-03-01

Nicotinamide has been shown to affect blood flow in both tumor and normal tissues, including skeletal muscle. Intraperitoneal injection of nicotinamide was used as a simple intervention to test the sensitivity of noninvasive diffuse correlation spectroscopy (DCS) to changes in blood flow in the murine left quadriceps femoris skeletal muscle. DCS was then compared with the gold-standard fluorescent microsphere (FM) technique for validation. The nicotinamide dose-response experiment showed that relative blood flow measured by DCS increased following treatment with 500- and 1000-mg / kg nicotinamide. The DCS and FM technique comparison showed that blood flow index measured by DCS was correlated with FM counts quantified by image analysis. The results of this study show that DCS is sensitive to nicotinamide-induced blood flow elevation in the murine left quadriceps femoris. Additionally, the results of the comparison were consistent with similar studies in higher-order animal models, suggesting that mouse models can be effectively employed to investigate the utility of DCS for various blood flow measurement applications.

Climate, Tree Growth, Forest Drought Stress, and Tree Mortality in Forests of Western North America: Long-Term Patterns and Recent Trends

NASA Astrophysics Data System (ADS)

Allen, C. D.; Williams, P.

2012-12-01

Ongoing climate changes are increasingly affecting the world's forests, particularly including high latitude and high elevation coniferous forests. Although forest growth has improved in some regions due to greater growing season length and warmth (perhaps along with increased atmospheric CO2 or N), large growth declines or increased mortality from droughts or hotter temperatures also are being observed. We present and interpret information on regional variation in climate-tree growth relationships and trends, and on patterns and trends of climate-related forest disturbances, from western North America. From 235 tree-ring chronologies in the Southwest US we show that tree-ring growth records from warmer southwestern sites are more sensitive to temperature than tree-ring growth records from cooler southwestern sites. Assessment of 59 tree-ring records from 11 species in the Cascade Mountains of the Pacific Northwest shows that trees growing in cool places respond positively to increased temperature and trees in warm places respond negatively, implying that trees historically not sensitive to temperature may become sensitive as mean temperatures warm. An analysis of 59 white spruce populations in Alaska supports the hypothesis that warming has caused tree growth to lose sensitivity to cold temperatures. Comparing ring widths to temperature during just the coldest 50% of years during the 20th century, tree growth was sensitive to cold temperatures, and this effect was strongest at the coldest sites; whereas during the warmest 50% of years, trees were not at all sensitive to cold temperatures, even at the cold sites. Drought and vapor pressure deficit are among the variables that emerge as being increasingly important to these Alaska boreal forests as mean temperatures rise. Most recently, from 346 tree-ring chronologies in the Southwest US we establish a tree-ring-based Forest Drought Stress Index (FDSI) for the three most widespread conifer species (Pinus edulis, Pinus ponderosa, and Pseudotsuga menziesii) in this region. FDSI responds sensitively and nonlinearly to growing season daily maximum temperatures which increase vapor pressure deficit, resulting in greater tree physiological stress and reduced tree growth. Drought conditions and warming temperatures in the Southwest since ca. 1996 have caused FDSI values in particular years since 2000 to start to exceed the most extreme values reconstructed from tree-rings for the past 1000 years for this region. FDSI demonstrates strong correlations with the spatial extent of major forest disturbances in the Southwest, including high-severity wildfire and bark beetle infestations, which over the past 20 years also have affected historically unprecedented levels. Similar trends of increasing extent and severity of forest disturbances are apparent across large portions of western North America. For the Southwest US, given relatively robust projections of substantial further increases in warmer temperatures and drought stress in coming decades, by ~2050 projected levels of FDSI and associated disturbances would reach extreme values, suggesting that current forest ecosystems likely would be forced to reorganize through wholesale tree mortality and the establishment of new dominant species.

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

Manouchehrian, M.; Larijani, M.M., E-mail: mmojtahedfr@yahooo.com; Elahi, S.M.

Highlights: • Tellurium thin films were prepared by thermal evaporation technique. • Tellurium thin films showed excellent gas-sensing properties to H{sub 2}S at room temperature. • Tellurium showed a remarkably enhanced response to H{sub 2}S gas under UV irradiation. • The reason of the enhanced response by UV irradiation was discussed. - Abstract: In this research, tellurium thin films were investigated for use as hydrogen sulfide gas sensors. To this end, a tellurium thin film has been deposited on Al{sub 2}O{sub 3} substrates by thermal evaporation, and the influence of thickness on the sensitivity of the tellurium thin film formore » measuring H{sub 2}S gas is studied. XRD patterns indicate that as the thickness increases, the crystallization improves. Observing the images obtained by SEM, it is seen that the grain size increases as the thickness increases. Studying the effect of thickness on H{sub 2}S gas measurement, it became obvious that as the thickness increases, the sensitivity decreases and the response and recovery times increase. To improve the response and recovery times of the tellurium thin film for measuring H{sub 2}S gas, the influence of UV radiation while measuring H{sub 2}S gas was also investigated. The results indicate that the response and recovery times strongly decrease using UV radiation.« less

Altered olfactory processing and increased insula activity in patients with obsessive-compulsive disorder: an fMRI study

PubMed Central

Berlin, Heather A.; Stern, Emily R.; Ng, Johnny; Zhang, Sam; Rosenthal, David; Turetzky, Rachel; Tang, Cheuk; Goodman, Wayne

2017-01-01

Obsessive-compulsive disorder (OCD) patients show increased insula activation to disgust-inducing images compared to healthy controls (HC). We explored whether this disgust reactivity was also present in the olfactory domain by conducting the first fMRI study of olfaction in OCD. Neural activation in response to pleasant and unpleasant odors (vs. unscented air) was investigated in 15 OCD and 15 HC participants using fMRI. OCD participants (vs. HC) had increased left anterior insula activation to unpleasant odors (vs. unscented air), which positively correlated with their disgust sensitivity and ratings of the unpleasantness and intensity of those odors. OCD participants (vs. HC) showed increased activation of caudate nucleus and left anterior and posterior insula to pleasant odors (vs. unscented air), which positively correlated with their OCD symptom severity, trait anxiety, frequency of feeling disgust, and odor intensity ratings. OCD participants had increased anterior insula activation to both pleasant and unpleasant odors, which correlated with their OCD symptoms, anxiety, disgust sensitivity, and frequency of feeling disgust. OCD patients might have a negative cognitive bias and experience all stimuli, regardless of valence, as being more unpleasant than healthy people. These findings further elucidate the neural underpinnings of OCD and may contribute to more effective treatments. PMID:28208068

nanostructures for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Rashad, M. M.; Shalan, A. E.

2014-08-01

Hierarchical architectures consisting of one-dimensional (1D) nanostructures are of great interest for potential use in energy and environmental applications in recent years. In this work, hierarchical tungsten oxide (WO3) has been synthesized via a facile hydrothermal route from ammonium metatungstate hydrate and implemented as photoelectrode for dye-sensitized solar cells. The urchin-like WO3 micro-patterns are constructed by self-organized nanoscale length 1D building blocks, which are single crystalline in nature, grown along (001) direction and confirm an orthorhombic crystal phase. The obtained powders were investigated by XRD, SEM, TEM and UV-Vis Spectroscopy. The photovoltaic performance of dye-sensitized solar cells based on WO3 photoanodes was investigated. With increasing the calcination temperature of the prepared nanopowders, the light-electricity conversion efficiency ( η) was increased. The results were attributed to increase the crystallinity of the particles and ease of electron movement. The DSSC based on hierarchical WO3 showed a short-circuit current, an open-circuit voltage, a fill factor, and a conversion efficiency of 4.241 mA/cm2, 0.656 V, 66.74, and 1.85 %, respectively.

The sensitivity of Bacillus subtilis to diverse antimicrobial compounds is influenced by Abh.

PubMed

Murray, Ewan J; Stanley-Wall, Nicola R

2010-12-01

Abh is a transition state regulator of Bacillus subtilis that controls biofilm formation and the production of several diverse antimicrobial compounds. Using a high-throughput non-biased technique, we show for the first time that Abh influences the sensitivity of B. subtilis to diverse antimicrobial compounds. Following up on these findings with a combination of classical genetics and antibiotic susceptibility assays, we demonstrate that Abh influences cellular processes such as the remodelling of the cell wall. We present data demonstrating that the extracytoplasmic function sigma factor σ(X) controls resistance to β-lactam antibiotics by activating abh transcription. Downstream from Abh, activation of slrR expression by Abh is responsible for controlling the sensitivity of B. subtilis to such antibiotics due to the role that SlrR plays in regulating autolysin biosynthesis. The abh mutant additionally exhibits increased resistance to aminoglycoside antimicrobials. We confirm that aminoglycoside killing of B. subtilis is likely to be caused by oxidative damage but rule out the possibility that the increased resistance of the abh mutant to aminoglycosides is due to a general increase in resistance to oxidative stress.

Comparing the effects of food restriction and overeating on brain reward systems

PubMed Central

Avena, Nicole M.; Murray, Susan; Gold, Mark S.

2014-01-01

Both caloric restriction and overeating have been shown to affect neural processes associated with reinforcement. Both preclinical and some clinical studies have provided evidence that food restriction may increase reward sensitivity, and while there are mixed findings regarding the effects of overeating on reward sensitivity, there is strong evidence linking this behavior with changes in reward-related brain regions. Evidence of these changes comes in part from findings that show that such eating patterns are associated with increased drug use. The data discussed here regarding the differential effects of various eating patterns on reward systems may be particularly relevant to the aging population, as this population has been shown to exhibit altered reward sensitivity and decreased caloric consumption. Moreover, members of this population appear to be increasingly affected by the current obesity epidemic. Food, like alcohol or drugs, can stimulate its own consumption and produce similar neurochemical changes in the brain. Age-related loss of appetite, decreased eating, and caloric restriction are hypothesized to be associated with changes in the prevalence of substance misuse, abuse, and dependence seen in this cohort. PMID:23535488

Nicotine Modifies Corticostriatal Plasticity and Amphetamine Rewarding Behaviors in Mice123

PubMed Central

Storey, Granville P.; Heimbigner, Lauren; Walwyn, Wendy M.; Bamford, Nigel S.

2016-01-01

Abstract Corticostriatal signaling participates in sensitized responses to drugs of abuse, where short-term increases in dopamine availability provoke persistent, yet reversible, changes in glutamate release. Prior studies in mice show that amphetamine withdrawal promotes a chronic presynaptic depression in glutamate release, whereas an amphetamine challenge reverses this depression by potentiating corticostriatal activity in direct pathway medium spiny neurons. This synaptic plasticity promotes corticostriatal activity and locomotor sensitization through upstream changes in the activity of tonically active cholinergic interneurons (ChIs). We used a model of operant drug-taking behaviors, in which mice self-administered amphetamine through an in-dwelling catheter. Mice acquired amphetamine self-administration under fixed and increasing schedules of reinforcement. Following a period of abstinence, we determined whether nicotinic acetylcholine receptors modified drug-seeking behavior and associated alterations in ChI firing and corticostriatal activity. Mice responding to conditioned reinforcement showed reduced ChI and corticostriatal activity ex vivo, which paradoxically increased following an amphetamine challenge. Nicotine, in a concentration that increases Ca2+ influx and desensitizes α4β2*-type nicotinic receptors, reduced amphetamine-seeking behaviors following abstinence and amphetamine-induced locomotor sensitization. Nicotine blocked the depression of ChI firing and corticostriatal activity and the potentiating response to an amphetamine challenge. Together, these results demonstrate that nicotine reduces reward-associated behaviors following repeated amphetamine and modifies the changes in ChIs firing and corticostriatal activity. By returning glutamatergic activity in amphetamine self-administering mice to a more stable and normalized state, nicotine limits the depression of striatal activity in withdrawal and the increase in activity following abstinence and a subsequent drug challenge. PMID:26866057

The impact of growing-season length variability on carbon assimilation and evapotranspiration over 88 years in the eastern US deciduous forest

PubMed

White; Running; Thornton

1999-02-01

Recent research suggests that increases in growing-season length (GSL) in mid-northern latitudes may be partially responsible for increased forest growth and carbon sequestration. We used the BIOME-BGC ecosystem model to investigate the impacts of including a dynamically regulated GSL on simulated carbon and water balance over a historical 88-year record (1900-1987) for 12 sites in the eastern USA deciduous broadleaf forest. For individual sites, the predicted GSL regularly varied by more than 15 days. When grouped into three climatic zones, GSL variability was still large and rapid. There is a recent trend in colder, northern sites toward a longer GSL, but not in moderate and warm climates. The results show that, for all sites, prediction of a long GSL versus using the mean GSL increased net ecosystem production (NEP), gross primary production (GPP), and evapotranspiration (ET); conversely a short GSL is predicted to decrease these parameters. On an absolute basis, differences in GPP between the dynamic and mean GSL simulations were larger than the differences in NEP. As a percentage difference, though, NEP was much more sensitive to changes in GSL than were either GPP or ET. On average, a 1-day change in GSL changed NEP by 1.6%, GPP by 0.5%, and ET by 0.2%. Predictions of NEP and GPP in cold climates were more sensitive to changes in GSL than were predictions in warm climates. ET was not similarly sensitive. First, our results strongly agree with field measurements showing a high correlation between NEP and dates of spring growth, and second they suggest that persistent increases in GSL may lead to long-term increases in carbon storage.

Hydroclimatic trends in simulations over the CORDEX North America region

NASA Astrophysics Data System (ADS)

Arritt, Raymond; Groisman, Pavel; Daniel, Ariele; Schillerberg, Tayler

2015-04-01

An increase in the occurrence of heavy precipitation has been one of the most pronounced climate change signals for the central United States. We study this trend by using the RegCM4 regional climate model to dynamically downscale CMIP5 global projections for 1950-2099 over the CORDEX North America domain. We examine the robustness of the results by driving the regional model with two different global models, by performing simulations at both 50 km and 25 km grid spacing, and by using different convective parameterizations in RegCM4. The global models sample the range of climate sensitivity in CMIP5: HadGEM2-ES has the highest equilibrium climate sensitivity of the CMIP5 models, while GFDL-ESM2M has one of the lowest sensitivities. RegCM4 results show increases in heavy precipitation (> 50 mm/day) over the central United States for the period 1951-2005 similar to observed trends. This trend is predicted to accelerate so that by the end of the 21st century incidence of heavy precipitation increases by a factor of 2 to 3. The trend is robust in that it is produced regardless of the driving global model or the configuration of the regional model. Results also show a modest increase in the number of dry days and a marked increase in the number of long runs of dry days (16 or more consecutive dry days). The combination of heavier events and longer runs of dry days has implications for sectors such as agriculture and water quality. This research was sponsored by USDA NIFA under the Earth System Modeling program and as part of a regional collaborative project.

Cocaine addiction is associated with abnormal prefrontal function, increased striatal connectivity and sensitivity to monetary incentives, and decreased connectivity outside the human reward circuit.

PubMed

Vaquero, Lucía; Cámara, Estela; Sampedro, Frederic; Pérez de Los Cobos, José; Batlle, Francesca; Fabregas, Josep Maria; Sales, Joan Artur; Cervantes, Mercè; Ferrer, Xavier; Lazcano, Gerardo; Rodríguez-Fornells, Antoni; Riba, Jordi

2017-05-01

Cocaine addiction has been associated with increased sensitivity of the human reward circuit to drug-related stimuli. However, the capacity of non-drug incentives to engage this network is poorly understood. Here, we characterized the functional sensitivity to monetary incentives and the structural integrity of the human reward circuit in abstinent cocaine-dependent (CD) patients and their matched controls. We assessed the BOLD response to monetary gains and losses in 30 CD patients and 30 healthy controls performing a lottery task in a magnetic resonance imaging scanner. We measured brain gray matter volume (GMV) using voxel-based morphometry and white matter microstructure using voxel-based fractional anisotropy (FA). Functional data showed that, after monetary incentives, CD patients exhibited higher activation in the ventral striatum than controls. Furthermore, we observed an inverted BOLD response pattern in the prefrontal cortex, with activity being highest after unexpected high gains and lowest after losses. Patients showed increased GMV in the caudate and the orbitofrontal cortex, increased white matter FA in the orbito-striatal pathway but decreased FA in antero-posterior association bundles. Abnormal activation in the prefrontal cortex correlated with GMV and FA increases in the orbitofrontal cortex. While functional abnormalities in the ventral striatum were inversely correlated with abstinence duration, structural alterations were not. In conclusion, results suggest abnormal incentive processing in CD patients with high salience for rewards and punishments in subcortical structures but diminished prefrontal control after adverse outcomes. They further suggest that hypertrophy and hyper-connectivity within the reward circuit, to the expense of connectivity outside this network, characterize cocaine addiction. © 2016 Society for the Study of Addiction.

Zinc Detoxification Is Required for Full Virulence and Modification of the Host Leaf Ionome by Xylella fastidiosa.

PubMed

Navarrete, Fernando; De La Fuente, Leonardo

2015-04-01

Zinc (Zn) is an essential element for all forms of life because it is a structural or catalytic cofactor of many proteins, but it can have toxic effects at high concentrations; thus, microorganisms must tightly regulate its levels. Here, we evaluated the role of Zn homeostasis proteins in the virulence of the xylem-limited bacterium Xylella fastidiosa, causal agent of Pierce's disease of grapevine, among other diseases. Two mutants of X. fastidiosa 'Temecula' affected in genes which regulate Zn homeostasis (zur) and Zn detoxification (czcD) were constructed. Both knockouts showed increased sensitivity to Zn at physiologically relevant concentrations and increased intracellular accumulation of this metal compared with the wild type. Increased Zn sensitivity was correlated with decreased growth in grapevine xylem sap, reduced twitching motility, and downregulation of exopolysaccharide biosynthetic genes. Tobacco plants inoculated with either knockout mutant showed reduced foliar symptoms and a much reduced (czcD) or absent (zur) modification of the leaf ionome (i.e., the mineral nutrient and trace element composition), as well as reduced bacterial populations. The results show that detoxification of Zn is crucial for the virulence of X. fastidiosa and verifies our previous findings that modification of the host leaf ionome correlates with bacterial virulence.

Increased androgenic sensitivity in the hind limb muscular system marks the evolution of a derived gestural display.

PubMed

Mangiamele, Lisa A; Fuxjager, Matthew J; Schuppe, Eric R; Taylor, Rebecca S; Hödl, Walter; Preininger, Doris

2016-05-17

Physical gestures are prominent features of many species' multimodal displays, yet how evolution incorporates body and leg movements into animal signaling repertoires is unclear. Androgenic hormones modulate the production of reproductive signals and sexual motor skills in many vertebrates; therefore, one possibility is that selection for physical signals drives the evolution of androgenic sensitivity in select neuromotor pathways. We examined this issue in the Bornean rock frog (Staurois parvus, family: Ranidae). Males court females and compete with rivals by performing both vocalizations and hind limb gestural signals, called "foot flags." Foot flagging is a derived display that emerged in the ranids after vocal signaling. Here, we show that administration of testosterone (T) increases foot flagging behavior under seminatural conditions. Moreover, using quantitative PCR, we also find that adult male S. parvus maintain a unique androgenic phenotype, in which androgen receptor (AR) in the hind limb musculature is expressed at levels ∼10× greater than in two other anuran species, which do not produce foot flags (Rana pipiens and Xenopus laevis). Finally, because males of all three of these species solicit mates with calls, we accordingly detect no differences in AR expression in the vocal apparatus (larynx) among taxa. The results show that foot flagging is an androgen-dependent gestural signal, and its emergence is associated with increased androgenic sensitivity within the hind limb musculature. Selection for this novel gestural signal may therefore drive the evolution of increased AR expression in key muscles that control signal production to support adaptive motor performance.

A quantitative analysis of sensitivity to the conditioned reinforcing value of terminal-link stimuli in a concurrent-chains schedule.

PubMed Central

Omino, T

1993-01-01

Pigeons were exposed to a concurrent-chains schedule in which a single variable-interval 30-s schedule was used in the initial links and fixed-time schedules were used in the terminal links. Three types of keylight conditions were used in the terminal links. In the first condition, different delays were associated with different keylight stimuli (cued condition). In the second condition, different delays were associated with the same stimulus, either a blackout (uncued blackout condition) or a white key (uncued white condition). Paired values of terminal-link fixed-time schedules differed by a constant ratio of 3:1, while the absolute value of delays was varied from 3 s to 54 s. The results showed that choice proportions for the shorter of two delays increased when the absolute size of the delays was increased for all keylight conditions. Further, the choice proportions for the shorter delay increased from the uncued blackout condition, to the uncued white condition, to the cued condition. A modified version of Fantino's (1969) delay-reduction model (expressed as a function relating the response ratio to the delay-reduction ratio) can be applied to these data by showing that sensitivity to delay reduction increased from the uncued blackout condition, to the uncued white condition, to the cued condition. Thus, the present study demonstrated that a modified version of the delay-reduction model can be used to assess quantitative differences in the terminal-link keylight condition in terms of sensitivity to delay reduction (i.e., the conditioned reinforcing value of the terminal-link keylight stimuli). PMID:8283150

Azilsartan treatment improves insulin sensitivity in obese spontaneously hypertensive Koletsky rats.

PubMed

Zhao, M; Li, Y; Wang, J; Ebihara, K; Rong, X; Hosoda, K; Tomita, T; Nakao, K

2011-12-01

Hypertension often coexists with insulin resistance. However, most metabolic effects of the antihypertensive agents have been investigated in nomotensive animals, in which different conclusions may arise. We investigated the metabolic effects of the new angiotensin II type 1 receptor blocker azilsartan using the obese Koletsky rats superimposed on the background of the spontaneously hypertensive rats. Male Koletsky rats were treated with azilsartan (2 mg/kg/day) over 3 weeks. Blood pressure was measured by tail-cuff. Blood biochemical and hormonal parameters were determined by enzymatic or ELISA methods. Gene expression was assessed by RT-PCR. In Koletsky rats, azilsartan treatment lowered blood pressure, basal plasma insulin concentration and the homeostasis model assessment of insulin resistance index, and inhibited over-increase of plasma glucose and insulin concentrations during oral glucose tolerance test. These effects were accompanied by decreases in both food intake and body weight (BW) increase. Although two treatments showed the same effect on BW gain, insulin sensitivity was higher after azilsartan treatment than pair-feeding. Azilsartan neither affected plasma concentrations of triglyceride and free fatty acids, nor increased adipose mRNA levels of peroxisome proliferator-activated receptor (PPAR)γ and its target genes such as adiponectin, aP2. In addition, azilsartan downregulated 11β-hydroxysteroid dehydrogenase type 1 expression. These results show the insulin-sensitizing effect of azilsartan in obese Koletsky rats. This effect is independent of decreases in food intake and BW increase or of the activation of adipose PPARγ. Our findings indicate the possible usefulness of azilsartan in the treatment of metabolic syndrome. © 2011 Blackwell Publishing Ltd.

Increased androgenic sensitivity in the hind limb muscular system marks the evolution of a derived gestural display

PubMed Central

Mangiamele, Lisa A.; Fuxjager, Matthew J.; Schuppe, Eric R.; Taylor, Rebecca S.; Hödl, Walter; Preininger, Doris

2016-01-01

Physical gestures are prominent features of many species’ multimodal displays, yet how evolution incorporates body and leg movements into animal signaling repertoires is unclear. Androgenic hormones modulate the production of reproductive signals and sexual motor skills in many vertebrates; therefore, one possibility is that selection for physical signals drives the evolution of androgenic sensitivity in select neuromotor pathways. We examined this issue in the Bornean rock frog (Staurois parvus, family: Ranidae). Males court females and compete with rivals by performing both vocalizations and hind limb gestural signals, called “foot flags.” Foot flagging is a derived display that emerged in the ranids after vocal signaling. Here, we show that administration of testosterone (T) increases foot flagging behavior under seminatural conditions. Moreover, using quantitative PCR, we also find that adult male S. parvus maintain a unique androgenic phenotype, in which androgen receptor (AR) in the hind limb musculature is expressed at levels ∼10× greater than in two other anuran species, which do not produce foot flags (Rana pipiens and Xenopus laevis). Finally, because males of all three of these species solicit mates with calls, we accordingly detect no differences in AR expression in the vocal apparatus (larynx) among taxa. The results show that foot flagging is an androgen-dependent gestural signal, and its emergence is associated with increased androgenic sensitivity within the hind limb musculature. Selection for this novel gestural signal may therefore drive the evolution of increased AR expression in key muscles that control signal production to support adaptive motor performance. PMID:27143723

EOSINOPHIL INFLUX TO THE NASAL AIRWAY FOLLOWING LOCAL, LOW-LEVEL LPS CHALLENGE IN HUMANS

EPA Science Inventory

Background: Recent obervations show that atopic asthmatic subjects have increased sensitivity to respirable endotoxin (or LPS) compared with normal persons. In vitro studies demonstrate that LPS enchances eosinophil survival. These obervations suggest that the effects of inhal...

Stratospheric water vapor feedback

PubMed Central

Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Davis, S. M.; Rosenlof, K. H.

2013-01-01

We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric water vapor feedback. We estimate the strength of this feedback in a chemistry–climate model to be +0.3 W/(m2⋅K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause. PMID:24082126

Temperature sensitivity and enzymatic mechanisms of soil organic matter decomposition along an altitudinal gradient on Mount Kilimanjaro

NASA Astrophysics Data System (ADS)

Blagodatskaya, Evgenia; Blagodatsky, Sergey; Khomyakov, Nikita; Myachina, Olga; Kuzyakov, Yakov

2016-02-01

Short-term acceleration of soil organic matter decomposition by increasing temperature conflicts with the thermal adaptation observed in long-term studies. Here we used the altitudinal gradient on Mt. Kilimanjaro to demonstrate the mechanisms of thermal adaptation of extra- and intracellular enzymes that hydrolyze cellulose, chitin and phytate and oxidize monomers (14C-glucose) in warm- and cold-climate soils. We revealed that no response of decomposition rate to temperature occurs because of a cancelling effect consisting in an increase in half-saturation constants (Km), which counteracts the increase in maximal reaction rates (Vmax with temperature). We used the parameters of enzyme kinetics to predict thresholds of substrate concentration (Scrit) below which decomposition rates will be insensitive to global warming. Increasing values of Scrit, and hence stronger canceling effects with increasing altitude on Mt. Kilimanjaro, explained the thermal adaptation of polymer decomposition. The reduction of the temperature sensitivity of Vmax along the altitudinal gradient contributed to thermal adaptation of both polymer and monomer degradation. Extrapolating the altitudinal gradient to the large-scale latitudinal gradient, these results show that the soils of cold climates with stronger and more frequent temperature variation are less sensitive to global warming than soils adapted to high temperatures.

Intranasal oxytocin increases neural responses to social reward in post-traumatic stress disorder

PubMed Central

van Zuiden, Mirjam; Koch, Saskia B.J.; Frijling, Jessie L.; Veltman, Dick J.; Olff, Miranda

2017-01-01

Abstract Therapeutic alliance and perceived social support are important predictors of treatment response for post-traumatic stress disorder (PTSD). Intranasal oxytocin administration may enhance treatment response by increasing sensitivity for social reward and thereby therapeutic alliance and perceived social support. As a first step to investigate this therapeutical potential, we investigated whether intranasal oxytocin enhances neural sensitivity to social reward in PTSD patients. Male and female police officers with (n = 35) and without PTSD (n = 37) were included in a double-blind, randomized, placebo-controlled cross-over fMRI study. After intranasal oxytocin (40 IU) and placebo administration, a social incentive delay task was conducted to investigate neural responses during social reward and punishment anticipation and feedback. Under placebo, PTSD patients showed reduced left anterior insula (AI) responses to social rewards (i.e. happy faces) compared with controls. Oxytocin administration increased left AI responses during social reward in PTSD patients, such that PTSD patients no longer differed from controls under placebo. Furthermore, in PTSD patients, oxytocin increased responses to social reward in the right putamen. By normalizing abberant insula responses and increasing putamen responses to social reward, oxytocin administration may enhance sensitivity for social support and therapeutic alliance in PTSD patients. Future studies are needed to investigate clinical effects of oxytocin. PMID:27614769

Determinants of altered intracellular endocrine-immune interplay in Bosnian war refugees suffering from PTSD.

PubMed

Pitts, Kenneth P; Joksimovic, Ljiljana; Steudte-Schmiedgen, Susann; Rohleder, Nicolas; Wolf, Jutta M

2016-07-01

Posttraumatic Stress Disorder (PTSD) has been repeatedly linked to changes in glucocorticoid (GC) sensitivity. To increase our understanding of this phenomenon and its potential relevance for PTSD development and treatment, the current study investigates the interplay between two key moderators, glucocorticoid receptor (GRα) and GR co-chaperone FKBP5, and their relation to GC sensitivity. A GC sensitivity assay was performed in 52 Bosnian war refugees (19m; 40.8±8.7 years) clinically diagnosed with PTSD to divide the patient group into a high (HS) and a low (LS) GC sensitivity group. Expression of GRα and FKBP5 mRNA was quantified by real-time RT-PCR. Links between gene expression and GC sensitivity were driven by the HS group of PTSD patients, which also showed increased expression of GRα but not FKBP5 compared to the LS group. Further, expressions of FKBP5 and GRα were strongly correlated in the HS patient group, while this association was missing in the LS PTSD group. Our findings suggest that PTSD phenotypes may be characterized by differences in intracellular signaling transduction processes. The associations of expression of GRα and FKBP5 in the high-sensitive PTSD subgroup may thereby reflect physiological adaptation to preserve immune-relevant GC signaling. Further research is needed to understand the role and consequences of GRα-FKBP5 dissociation in low GC sensitivity PTSD patients. Copyright © 2016 Elsevier B.V. All rights reserved.

Light and the circadian clock mediate time-specific changes in sensitivity to UV-B stress under light/dark cycles

PubMed Central

Takeuchi, Tomomi; Newton, Linsey; Burkhardt, Alyssa; Mason, Saundra; Farré, Eva M.

2014-01-01

In Arabidopsis, the circadian clock regulates UV-B-mediated changes in gene expression. Here it is shown that circadian clock components are able to inhibit UV-B-induced gene expression in a gene-by-gene-specific manner and act downstream of the initial UV-B sensing by COP1 (CONSTITUTIVE PHOTOMORPHOGENIC 1) and UVR8 (UV RESISTANCE LOCUS 8). For example, the UV-B induction of ELIP1 (EARLY LIGHT INDUCIBLE PROTEIN 1) and PRR9 (PSEUDO-RESPONSE REGULATOR 9) is directly regulated by LUX (LUX ARRYTHMO), ELF4 (EARLY FLOWERING 4), and ELF3. Moreover, time-dependent changes in plant sensitivity to UV-B damage were observed. Wild-type Arabidopsis plants, but not circadian clock mutants, were more sensitive to UV-B treatment during the night periods than during the light periods under diel cycles. Experiments performed under short cycles of 6h light and 6h darkness showed that the increased stress sensitivity of plants to UV-B in the dark only occurred during the subjective night and not during the subjective day in wild-type seedlings. In contrast, the stress sensitivity of Arabidopsis mutants with a compromised circadian clock was still influenced by the light condition during the subjective day. Taken together, the results show that the clock and light modulate plant sensitivity to UV-B stress at different times of the day. PMID:25147271

Population receptive field (pRF) measurements of chromatic responses in human visual cortex using fMRI.

PubMed

Welbourne, Lauren E; Morland, Antony B; Wade, Alex R

2018-02-15

The spatial sensitivity of the human visual system depends on stimulus color: achromatic gratings can be resolved at relatively high spatial frequencies while sensitivity to isoluminant color contrast tends to be more low-pass. Models of early spatial vision often assume that the receptive field size of pattern-sensitive neurons is correlated with their spatial frequency sensitivity - larger receptive fields are typically associated with lower optimal spatial frequency. A strong prediction of this model is that neurons coding isoluminant chromatic patterns should have, on average, a larger receptive field size than neurons sensitive to achromatic patterns. Here, we test this assumption using functional magnetic resonance imaging (fMRI). We show that while spatial frequency sensitivity depends on chromaticity in the manner predicted by behavioral measurements, population receptive field (pRF) size measurements show no such dependency. At any given eccentricity, the mean pRF size for neuronal populations driven by luminance, opponent red/green and S-cone isolating contrast, are identical. Changes in pRF size (for example, an increase with eccentricity and visual area hierarchy) are also identical across the three chromatic conditions. These results suggest that fMRI measurements of receptive field size and spatial resolution can be decoupled under some circumstances - potentially reflecting a fundamental dissociation between these parameters at the level of neuronal populations. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Fusogenic activity of PEGylated pH-sensitive liposomes.

PubMed

Vanić, Zeljka; Barnert, Sabine; Süss, Regine; Schubert, Rolf

2012-06-01

The aim of this study was to investigate the fusogenic properties of poly(ethylene glycol) (PEG)ylated dioleoylphosphatidylethanolamine/cholesteryl hemisuccinate (DOPE/CHEMS) liposomes. These pH-sensitive liposomes were prepared by incorporating two different PEG lipids: distearoylphosphatidylethanolamine (DSPE)-PEG₂₀₀₀ was mixed with the liposomal lipids using the conventional method, whereas sterol-PEG₁₁₀₀ was inserted into the outer monolayer of preformed vesicles. Both types of PEGylated liposomes were characterized and compared for their entrapment efficiency, zeta potential and size, and were tested in vitro for pH sensitivity by means of proton-induced leakage and membrane fusion activity. To mimic the routes of intracellular delivery, fusion between pH-sensitive liposomes and liposomes designed to simulate the endosomal membrane was studied. Our investigations confirmed that DOPE/CHEMS liposomes were capable of rapidly releasing calcein and of fusing upon acidification. However, after incorporation of DSPE-PEG₂₀₀₀ or sterol-PEG₁₁₀₀ into the membrane, pH sensitivity was significantly reduced; as the mol ratio of PEG-lipid was increased, the ability to fuse was decreased. Comparison between two different PEGylated pH-sensitive liposomes showed that only vesicles containing 0.6 mol% sterol-PEG₁₁₀₀ in the outer monolayer were still capable of fusing with the endosome-like liposomes and showing leakage of calcein at pH 5.5.

A small group of neurosecretory cells expressing the transcriptional regulator apontic and the neuropeptide corazonin mediate ethanol sedation in Drosophila.

PubMed

McClure, Kimberly D; Heberlein, Ulrike

2013-02-27

In the fruit fly Drosophila melanogaster, as in mammals, acute exposure to a high dose of ethanol leads to stereotypical behavioral changes beginning with increased activity, followed by incoordination, loss of postural control, and eventually, sedation. The mechanism(s) by which ethanol impacts the CNS leading to ethanol-induced sedation and the genes required for normal sedation sensitivity remain largely unknown. Here we identify the gene apontic (apt), an Myb/SANT-containing transcription factor that is required in the nervous system for normal sensitivity to ethanol sedation. Using genetic and behavioral analyses, we show that apt mediates sensitivity to ethanol sedation by acting in a small set of neurons that express Corazonin (Crz), a neuropeptide likely involved in the physiological response to stress. The activity of Crz neurons regulates the behavioral response to ethanol, as silencing and activating these neurons affects sedation sensitivity in opposite ways. Furthermore, this effect is mediated by Crz, as flies with reduced crz expression show reduced sensitivity to ethanol sedation. Finally, we find that both apt and crz are rapidly upregulated by acute ethanol exposure. Thus, we have identified two genes and a small set of peptidergic neurons that regulate sensitivity to ethanol-induced sedation. We propose that Apt regulates the activity of Crz neurons and/or release of the neuropeptide during ethanol exposure.

A Small Group of Neurosecretory Cells Expressing the Transcriptional Regulator apontic and the Neuropeptide corazonin Mediate Ethanol Sedation in Drosophila

PubMed Central

2013-01-01

In the fruit fly Drosophila melanogaster, as in mammals, acute exposure to a high dose of ethanol leads to stereotypical behavioral changes beginning with increased activity, followed by incoordination, loss of postural control, and eventually, sedation. The mechanism(s) by which ethanol impacts the CNS leading to ethanol-induced sedation and the genes required for normal sedation sensitivity remain largely unknown. Here we identify the gene apontic (apt), an Myb/SANT-containing transcription factor that is required in the nervous system for normal sensitivity to ethanol sedation. Using genetic and behavioral analyses, we show that apt mediates sensitivity to ethanol sedation by acting in a small set of neurons that express Corazonin (Crz), a neuropeptide likely involved in the physiological response to stress. The activity of Crz neurons regulates the behavioral response to ethanol, as silencing and activating these neurons affects sedation sensitivity in opposite ways. Furthermore, this effect is mediated by Crz, as flies with reduced crz expression show reduced sensitivity to ethanol sedation. Finally, we find that both apt and crz are rapidly upregulated by acute ethanol exposure. Thus, we have identified two genes and a small set of peptidergic neurons that regulate sensitivity to ethanol-induced sedation. We propose that Apt regulates the activity of Crz neurons and/or release of the neuropeptide during ethanol exposure. PMID:23447613