Huge increase in gas phase nanoparticle generation by pulsed direct current sputtering in a reactive gas admixture

NASA Astrophysics Data System (ADS)

Polonskyi, Oleksandr; Peter, Tilo; Mohammad Ahadi, Amir; Hinz, Alexander; Strunskus, Thomas; Zaporojtchenko, Vladimir; Biederman, Hynek; Faupel, Franz

2013-07-01

Using reactive DC sputtering in a gas aggregation cluster source, we show that pulsed discharge gives rise to a huge increase in deposition rate of nanoparticles by more than one order of magnitude compared to continuous operation. We suggest that this effect is caused by an equilibrium between slight target oxidation (during "time-off") and subsequent sputtering of Ti oxides (sub-oxides) at "time-on" with high power impulse.

Desomorphine Screening Using Commercial Enzyme-Linked Immunosorbent Assays.

PubMed

Winborn, Jessica; Kerrigan, Sarah

2017-06-01

Desomorphine ("Krokodil") is a semi-synthetic opioid that has drawn attention as a recreational drug, particularly in Russia, neighboring former Soviet Republics, Eastern and Central Europe. It has no accepted medicinal uses and is currently a schedule I drug in the United States. In clandestine environments, desomorphine is synthesized from codeine using red phosphorous, hydroiodic acid and gasoline. Residual starting materials in illicit preparations have been associated with severe dermatological effects and extensive tissue necrosis. Desomorphine is not well studied, and there are limited reports concerning its pharmacology or detection in biological matrices. Immunoassays are widely relied upon for both antemortem and postmortem toxicology screening. Although desomorphine is an opioid of the phenanthrene-type, its ability to bind to conventional opioid antibodies has not been described. In this report we describe the cross-reactivity of desomorphine using six commercially available enzyme-linked immunosorbent assays (Immunalysis Opiates Direct ELISA, Immunalysis Oxycodone/Oxymorphone Direct ELISA, Randox Opiate ELISA, OraSure Technologies OTI Opiate Micro-plate EIA, Neogen Opiate Group ELISA and Neogen Oxycodone/Oxymorphone ELISA). Cross-reactivites were highly variable between assays, ranging from 77 to <2.5%. In general, assays directed towards morphine produced greater cross-reactivity with desomorphine than those directed towards oxycodone. The Immunalysis Opiates Direct ELISA produced the greatest cross-reactivity, although several of the assays evaluated produced cross-reactivity of a sufficient magnitude to be effective for desomorphine screening. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Reactive Agility Performance in Handball; Development and Evaluation of a Sport-Specific Measurement Protocol

PubMed Central

Spasic, Miodrag; Krolo, Ante; Zenic, Natasa; Delextrat, Anne; Sekulic, Damir

2015-01-01

There is no current study that examined sport-specific tests of reactive-agility and change-of-direction-speed (CODS) to replicate real-sport environment in handball (team-handball). This investigation evaluated the reliability and validity of two novel tests designed to assess reactive-agility and CODS of handball players. Participants were female (25.14 ± 3.71 years of age; 1.77 ± 0.09 m and 74.1 ± 6.1 kg) and male handball players (26.9 ± 4.1 years of age; 1.90 ± 0.09 m and 93.90±4.6 kg). Variables included body height, body mass, body mass index, broad jump, 5-m sprint, CODS and reactive-agility tests. Results showed satisfactory reliability for reactive-agility-test and CODS-test (ICC of 0.85-0.93, and CV of 2.4-4.8%). The reactive-agility and CODS shared less than 20% of the common variance. The calculated index of perceptual and reactive capacity (P&RC; ratio between reactive-agility- and CODS-performance) is found to be valid measure in defining true-game reactive-agility performance in handball in both genders. Therefore, the handball athletes’ P&RC should be used in the evaluation of real-game reactive-agility performance. Future studies should explore other sport-specific reactive-agility tests and factors associated to such performance in sports involving agile maneuvers. Key points Reactive agility and change-of-direction-speed should be observed as independent qualities, even when tested over the same course and similar movement template The reactive-agility-performance of the handball athletes involved in defensive duties is closer to their non-reactive-agility-score than in their peers who are not involved in defensive duties The handball specific “true-game” reactive-agility-performance should be evaluated as the ratio between reactive-agility and corresponding CODS performance. PMID:26336335

Reactive Agility Performance in Handball; Development and Evaluation of a Sport-Specific Measurement Protocol.

PubMed

Spasic, Miodrag; Krolo, Ante; Zenic, Natasa; Delextrat, Anne; Sekulic, Damir

2015-09-01

There is no current study that examined sport-specific tests of reactive-agility and change-of-direction-speed (CODS) to replicate real-sport environment in handball (team-handball). This investigation evaluated the reliability and validity of two novel tests designed to assess reactive-agility and CODS of handball players. Participants were female (25.14 ± 3.71 years of age; 1.77 ± 0.09 m and 74.1 ± 6.1 kg) and male handball players (26.9 ± 4.1 years of age; 1.90 ± 0.09 m and 93.90±4.6 kg). Variables included body height, body mass, body mass index, broad jump, 5-m sprint, CODS and reactive-agility tests. Results showed satisfactory reliability for reactive-agility-test and CODS-test (ICC of 0.85-0.93, and CV of 2.4-4.8%). The reactive-agility and CODS shared less than 20% of the common variance. The calculated index of perceptual and reactive capacity (P&RC; ratio between reactive-agility- and CODS-performance) is found to be valid measure in defining true-game reactive-agility performance in handball in both genders. Therefore, the handball athletes' P&RC should be used in the evaluation of real-game reactive-agility performance. Future studies should explore other sport-specific reactive-agility tests and factors associated to such performance in sports involving agile maneuvers. Key pointsReactive agility and change-of-direction-speed should be observed as independent qualities, even when tested over the same course and similar movement templateThe reactive-agility-performance of the handball athletes involved in defensive duties is closer to their non-reactive-agility-score than in their peers who are not involved in defensive dutiesThe handball specific "true-game" reactive-agility-performance should be evaluated as the ratio between reactive-agility and corresponding CODS performance.

Mutagenic and genotoxic potential of direct electric current in Escherichia coli and Salmonella thyphimurium strains.

PubMed

Gomes, Marina das Neves; Cardoso, Janine Simas; Leitão, Alvaro Costa; Quaresma, Carla Holandino

2016-05-01

Direct electric current has several therapeutic uses such as antibacterial and antiprotozoal action, tissues scarring and regeneration, as well as tumor treatment. This method has shown promising results in vivo and in vitro, with significant efficacy and almost no side effects. Considering lack of studies regarding direct electric current mutagenic and/or genotoxic effects, the present work evaluated both aspects by using five different bacterial experimental assays: survival of repair-deficient mutants, Salmonella-histidine reversion mutagenesis (Ames test), forward mutations to rifampicin resistance, phage reactivation, and lysogenic induction. In these experimental conditions, cells were submitted to an approach that allows evaluation of anodic, cathodic, and electro-ionic effects generated by 2 mA of direct electric current, with doses ranging from 0.36 to 3.60 Coulombs. Our results showed these doses did not induce mutagenic or genotoxic effects. © 2016 Wiley Periodicals, Inc.

Optical properties of aluminum-doped zinc oxide films deposited by direct-current pulse magnetron reactive sputtering

NASA Astrophysics Data System (ADS)

Gao, Xiao-Yong; Chen, Chao; Zhang, Sa

2014-03-01

A series of <103>-oriented aluminum-doped zinc oxide (AZO) films were deposited on glass substrates via direct-current pulse magnetron reactive sputtering at different O2-to-Ar gas flow ratios (GFRs). The optical properties of the films were characterized using the fitted optical constants in the general oscillator model (which contains two Psemi-Tri oscillators) through the use of measured ellipsometric parameters. The refractive index dispersion data below the interband absorption edge were analyzed using a single-oscillator model. The fitted optical energy gap obtained using the single-oscillator model clearly shows a blue shift, followed by a red shift, as the GFR increases from 0.9/18 to 2.1/18. This shift can be attributed to the change in the free electron concentration of the film, which is closely related to the film stress. In addition, the fitted β value indicates that the AZO film falls under the ionic class. The photoluminescence spectrum indicates a photoluminescence mechanism of the direct and wide energy gap semiconductor.

Impact of Alcohol Use Disorder Comorbidity on Defensive Reactivity to Errors in Veterans with Post-traumatic Stress Disorder

PubMed Central

Gorka, Stephanie M.; MacNamara, Annmarie; Aase, Darrin M.; Proescher, Eric; Greenstein, Justin E.; Walters, Robert; Passi, Holly; Babione, Joseph M.; Levy, David M.; Kennedy, Amy E.; DiGangi, Julia A.; Rabinak, Christine A.; Schroth, Christopher; Afshar, Kaveh; Fitzgerald, Jacklynn; Hajcak, Greg; Phan, K. Luan

2017-01-01

Converging lines of evidence suggest that individuals with comorbid post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) may be characterized by heightened defensive reactivity, which serves to maintain drinking behaviors and anxiety/hyperarousal symptoms. Notably, however, very few studies have directly tested whether individuals with PTSD and AUD exhibit greater defensive reactivity compared with individuals with PTSD without AUD. The aim of the current study was to therefore test this emerging hypothesis by examining individual differences in error related negativity (ERN), an event-related component that is larger among anxious individuals and is thought to reflect defensive reactivity to errors. Participants were sixty-six military veterans who completed a well-validated flanker task known to robustly elicit the ERN. Veterans were comprised of three groups: controls (i.e., no PTSD or AUD), PTSD-AUD (i.e., current PTSD but no AUD), and PTSD+AUD (i.e., current comorbid PTSD and AUD). Results indicated that in general, individuals with PTSD and controls did not differ in ERN amplitude. However, among individuals with PTSD, those with comorbid AUD had significantly larger ERNs than those without AUD. These findings suggest that PTSD+AUD is a neurobiologically unique subtype of PTSD and the comorbidity of AUD may enhance defensive reactivity to errors in individuals with PTSD. PMID:27786513

Differential Autonomic Nervous System Reactivity in Depression and Anxiety During Stress Depending on Type of Stressor.

PubMed

Hu, Mandy X; Lamers, Femke; de Geus, Eco J C; Penninx, Brenda W J H

2016-06-01

It remains unclear whether depressive and anxiety disorders are associated with hyporeactivity or hyperreactivity of the autonomic nervous system (ANS) and whether deviant reactivity occurs in all types of stressors. This study compared ANS reactivity in people with current or remitted depression/anxiety with reactivity in healthy controls during two stress conditions. From the Netherlands Study of Depression and Anxiety, data of 804 individuals with current depression/anxiety, 913 individuals with remitted depression/anxiety, and 466 healthy controls (mean age = 44.1 years; 66.4% female) were available. Two conditions were used to evoke stress: a) an n-back task, a cognitively challenging stressor, and 2) a psychiatric interview, evoking personal-emotional stress related to the occurrence of symptoms of depression/anxiety. Indicators of ANS activity were heart rate (HR), root mean square of differences between successive interbeat intervals (RMSSD), respiratory sinus arrhythmia (RSA), and preejection period. As compared with controls, participants with psychopathology had significant hyporeactivity of HR (controls = 4.1 ± 4.2 beats/min; remitted = 3.5 ± 3.5 beats/min; current psychopathology = 3.1 ± 3.4 beats/min), RMSSD (controls = -6.2 ± 14.5 milliseconds; remitted = -5.4 ± 17.8 milliseconds; current psychopathology = -3.5 ± 15.4 milliseconds), and RSA (controls = -9.3 ± 17.0 milliseconds; remitted = -7.4 ± 16.5 milliseconds; current psychopathology = -6.9 ± 15.0 milliseconds) during the n-back task. In contrast, during the psychiatric interview, they showed significant hyperreactivity of HR (controls = 2.7 ± 3.4 beats/min; remitted = 3.5 ± 3.4 beats/min; current psychopathology = 4.0 ± 3.3 beats/min), RMSSD (controls = -3.4 ± 12.2 milliseconds; remitted = -4.1 ± 12.1 milliseconds; current psychopathology = -5.6 ± 11.8 milliseconds), and RSA (controls = -3.8 ± 8.1 milliseconds; remitted = -4.3 ± 7.9 milliseconds; current psychopathology = -5.0 ± 7.9 milliseconds). The lack of group differences in preejection period reactivity suggests that the found effects were driven by altered cardiac vagal reactivity in depression/anxiety. The direction of altered ANS reactivity in depressed/anxious patients is dependent on the type of stressor, and only the more ecologically valid stressors may evoke hyperreactivity in these patients.

Towards validated chemistry at extreme conditions: reactive MD simulations of shocked Polyvinyl Nitrate and Nitromethane

NASA Astrophysics Data System (ADS)

Islam, Md Mahbubul; Strachan, Alejandro

A detailed atomistic-level understanding of the ultrafast chemistry of detonation processes of high energy materials is crucial to understand their performance and safety. Recent advances in laser shocks and ultra-fast spectroscopy is yielding the first direct experimental evidence of chemistry at extreme conditions. At the same time, reactive molecular dynamics (MD) in current high-performance computing platforms enable an atomic description of shock-induced chemistry with length and timescales approaching those of experiments. We use MD simulations with the reactive force field ReaxFF to investigate the shock-induced chemical decomposition mechanisms of polyvinyl nitrate (PVN) and nitromethane (NM). The effect of shock pressure on chemical reaction mechanisms and kinetics of both the materials are investigated. For direct comparison of our simulation results with experimentally derived IR absorption data, we performed spectral analysis using atomistic velocity at various shock conditions. The combination of reactive MD simulations and ultrafast spectroscopy enables both the validation of ReaxFF at extreme conditions and contributes to the interpretation of the experimental data relating changes in spectral features to atomic processes. Office of Naval Research MURI program.

Sulfenic acid chemistry, detection and cellular lifetime☆

PubMed Central

Gupta, Vinayak; Carroll, Kate S.

2014-01-01

Background Reactive oxygen species-mediated cysteine sulfenic acid modification has emerged as an important regulatory mechanism in cell signaling. The stability of sulfenic acid in proteins is dictated by the local microenvironment and ability of antioxidants to reduce this modification. Several techniques for detecting this cysteine modification have been developed, including direct and in situ methods. Scope of review This review presents a historical discussion of sulfenic acid chemistry and highlights key examples of this modification in proteins. A comprehensive survey of available detection techniques with advantages and limitations is discussed. Finally, issues pertaining to rates of sulfenic acid formation, reduction, and chemical trapping methods are also covered. Major conclusions Early chemical models of sulfenic acid yielded important insights into the unique reactivity of this species. Subsequent pioneering studies led to the characterization of sulfenic acid formation in proteins. In parallel, the discovery of oxidant-mediated cell signaling pathways and pathological oxidative stress has led to significant interest in methods to detect these modifications. Advanced methods allow for direct chemical trapping of protein sulfenic acids directly in cells and tissues. At the same time, many sulfenic acids are short-lived and the reactivity of current probes must be improved to sample these species, while at the same time, preserving their chemical selectivity. Inhibitors with binding scaffolds can be rationally designed to target sulfenic acid modifications in specific proteins. General significance Ever increasing roles for protein sulfenic acids have been uncovered in physiology and pathology. A more complete understanding of sulfenic acid-mediated regulatory mechanisms will continue to require rigorous and new chemical insights. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn. PMID:23748139

Measurement of Reactive Oxygen Species, Reactive Nitrogen Species, and Redox-Dependent Signaling in the Cardiovascular System: A Scientific Statement From the American Heart Association.

PubMed

Griendling, Kathy K; Touyz, Rhian M; Zweier, Jay L; Dikalov, Sergey; Chilian, William; Chen, Yeong-Renn; Harrison, David G; Bhatnagar, Aruni

2016-08-19

Reactive oxygen species and reactive nitrogen species are biological molecules that play important roles in cardiovascular physiology and contribute to disease initiation, progression, and severity. Because of their ephemeral nature and rapid reactivity, these species are difficult to measure directly with high accuracy and precision. In this statement, we review current methods for measuring these species and the secondary products they generate and suggest approaches for measuring redox status, oxidative stress, and the production of individual reactive oxygen and nitrogen species. We discuss the strengths and limitations of different methods and the relative specificity and suitability of these methods for measuring the concentrations of reactive oxygen and reactive nitrogen species in cells, tissues, and biological fluids. We provide specific guidelines, through expert opinion, for choosing reliable and reproducible assays for different experimental and clinical situations. These guidelines are intended to help investigators and clinical researchers avoid experimental error and ensure high-quality measurements of these important biological species. © 2016 American Heart Association, Inc.

Micro-chip initiator realized by integrating Al/CuO multilayer nanothermite on polymeric membrane

NASA Astrophysics Data System (ADS)

Taton, G.; Lagrange, D.; Conedera, V.; Renaud, L.; Rossi, C.

2013-10-01

We have developed a new nanothermite based polymeric electro-thermal initiator for non-contact ignition of a propellant. A reactive Al/CuO multilayer nanothermite resides on a 100 µm thick SU-8/PET (polyethyleneterephtalate) membrane to insulate the reactive layer from the silicon bulk substrate. When current is supplied to the initiator, the chemical reaction Al+CuO occurs and sparkles are spread to a distance of several millimeters. A micro-manufacturing process for fabricating the initiator is presented and the electrical behaviors of the ignition elements are also investigated. The characteristics of the initiator made on a 100 µm thick SU-8/PET membrane were compared to two bulk electro-thermal initiators: one on a silicon and one on a Pyrex substrate. The PET devices give 100% of Al/CuO ignition success for an electrical current >250 mA. Glass based reactive initiators give 100% of Al/CuO ignition success for an electrical current >500 mA. Reactive initiators directly on silicon cannot initiate even with a 4 A current. At low currents (<1 A), the initiation time is two orders of magnitude longer for Pyrex initiator compared to those obtained for PET initiator technology. We also observed that, the Al/CuO thermite film on PET membrane reacts within 1 ms (sparkles duration) whereas it reacts within 4 ms on Pyrex. The thermite reaction is 40 times greater in intensity using the PET substrate in comparison to Pyrex.

Results of the harmonics measurement program at the John F. Long photovoltaic house

NASA Astrophysics Data System (ADS)

Campen, G. L.

1982-03-01

Photovoltaic (PV) systems used in single-family dwellings require an inverter to act as an interface between the direct-current (dc) power output of the PV unit and the alternating-current (ac) power needed by house loads. A type of inverter known as line commutated injects harmonic currents on the ac side and requires large amounts of reactive power. Large numbers of such PV installations could lead to unacceptable levels of harmonic voltages on the utility system, and the need to increase the utility's deliver of reactive power could result in significant cost increases. The harmonics and power-factor effects are examined for a single PV installation using a line-commutated inverter. The magnitude and phase of various currents and voltages from the fundamental to the 13th harmonic were recorded both with and without the operation of the PV system.

Spin-Orbit Torques and Anisotropic Magnetization Damping in Skyrmion Crystals

NASA Astrophysics Data System (ADS)

Hals, Kjetil; Brataas, Arne

2014-03-01

We theoretically study the effects of reactive and dissipative homogeneous spin-orbit torques and anisotropic damping on the current-driven skyrmion dynamics in cubic chiral magnets. Our results demonstrate that spin-orbit torques play a significant role in the current-induced skyrmion velocity. The dissipative spin-orbit torque generates a relativistic Magnus force on the skyrmions, whereas the reactive spin-orbit torque yields a correction to both the drift velocity along the current direction and the transverse velocity associated with the Magnus force. The spin-orbit torque corrections to the velocity scale linearly with the skyrmion size, which is inversely proportional to the spin-orbit coupling. Consequently, the reactive spin-orbit torque correction can be the same order of magnitude as the non-relativistic contribution. More importantly, the dissipative spin-orbit torque can be the dominant force that causes a deflected motion of the skyrmions if the torque exhibits a linear or quadratic relationship with the spin-orbit coupling. In addition, we demonstrate that the skyrmion velocity is determined by anisotropic magnetization damping parameters governed by the skyrmion size.

Interaction of nanoparticles with proteins: relation to bio-reactivity of the nanoparticle.

PubMed

Saptarshi, Shruti R; Duschl, Albert; Lopata, Andreas L

2013-07-19

Interaction of nanoparticles with proteins is the basis of nanoparticle bio-reactivity. This interaction gives rise to the formation of a dynamic nanoparticle-protein corona. The protein corona may influence cellular uptake, inflammation, accumulation, degradation and clearance of the nanoparticles. Furthermore, the nanoparticle surface can induce conformational changes in adsorbed protein molecules which may affect the overall bio-reactivity of the nanoparticle. In depth understanding of such interactions can be directed towards generating bio-compatible nanomaterials with controlled surface characteristics in a biological environment. The main aim of this review is to summarise current knowledge on factors that influence nanoparticle-protein interactions and their implications on cellular uptake.

Bioactive ceramic-based materials with designed reactivity for bone tissue regeneration

PubMed Central

Ohtsuki, Chikara; Kamitakahara, Masanobu; Miyazaki, Toshiki

2009-01-01

Bioactive ceramics have been used clinically to repair bone defects owing to their biological affinity to living bone; i.e. the capability of direct bonding to living bone, their so-called bioactivity. However, currently available bioactive ceramics do not satisfy every clinical application. Therefore, the development of novel design of bioactive materials is necessary. Bioactive ceramics show osteoconduction by formation of biologically active bone-like apatite through chemical reaction of the ceramic surface with surrounding body fluid. Hence, the control of their chemical reactivity in body fluid is essential to developing novel bioactive materials as well as biodegradable materials. This paper reviews novel bioactive materials designed based on chemical reactivity in body fluid. PMID:19158015

Atmospheric Pressure Plasma Jet for Chem/Bio Warfare Decontamination

NASA Astrophysics Data System (ADS)

Herrmann, Hans W.; Henins, Ivars; Park, Jaeyoung; Selwyn, Gary S.

1999-11-01

Atmospheric Pressure Plasma Jet (APPJ) technology may provide a much needed method of CBW decontamination which, unlike traditional decon methods, is dry and nondestructive to sensitive equipment and materials. The APPJ discharge uses a high-flow feedgas consisting primarily of an inert carrier gas, such as He, and a small amount of a reactive additive, such as O2, which flows between capacitively-coupled electrodes powered at 13.56 MHz. The plasma generates highly reactive metastable and atomic species of oxygen which are then directed onto a contaminated surface. The reactive effluent of the APPJ has been shown to effectively neutralize VX nerve agent as well as simulants for anthrax and mustard blister agent. Research efforts are now being directed towards reducing He consumption and increasing the allowable stand-off distance. Recent results demonstrate that by replacing the O2 reactive additive with CO2, ozone formation is greatly reduced. This has the result of extending the lifetime of atomic oxygen by an order of magnitude or more. A recirculating APP Decon Chamber which combines heat, vacuum, forced convection and reactivity is currently being developed for enhanced decontamination of sensitive equipment. Several techniques are also being evaluated for use in an APP Decon Jet for decontamination of items which cannot be placed inside a chamber.

Exposure of Bacterial Biofilms to Electrical Current Leads to Cell Death Mediated in Part by Reactive Oxygen Species.

PubMed

Brinkman, Cassandra L; Schmidt-Malan, Suzannah M; Karau, Melissa J; Greenwood-Quaintance, Kerryl; Hassett, Daniel J; Mandrekar, Jayawant N; Patel, Robin

2016-01-01

Bacterial biofilms may form on indwelling medical devices such as prosthetic joints, heart valves and catheters, causing challenging-to-treat infections. We have previously described the 'electricidal effect', in which bacterial biofilms are decreased following exposure to direct electrical current. Herein, we sought to determine if the decreased bacterial quantities are due to detachment of biofilms or cell death and to investigate the role that reactive oxygen species (ROS) play in the observed effect. Using confocal and electron microscopy and flow cytometry, we found that direct current (DC) leads to cell death and changes in the architecture of biofilms formed by Gram-positive and Gram-negative bacteria. Reactive oxygen species (ROS) appear to play a role in DC-associated cell death, as there was an increase in ROS-production by Staphylococcus aureus and Staphylococcus epidermidis biofilms following exposure to DC. An increase in the production of ROS response enzymes catalase and superoxide dismutase (SOD) was observed for S. aureus, S. epidermidis and Pseudomonas aeruginosa biofilms following exposure to DC. Additionally, biofilms were protected from cell death when supplemented with antioxidants and oxidant scavengers, including catalase, mannitol and Tempol. Knocking out SOD (sodAB) in P. aeruginosa led to an enhanced DC effect. Microarray analysis of P. aeruginosa PAO1 showed transcriptional changes in genes related to the stress response and cell death. In conclusion, the electricidal effect results in death of bacteria in biofilms, mediated, at least in part, by production of ROS.

A new method for total OH reactivity measurements using a fast Gas Chromatographic Photo-Ionization Detector (GC-PID)

NASA Astrophysics Data System (ADS)

Nölscher, A. C.; Sinha, V.; Bockisch, S.; Klüpfel, T.; Williams, J.

2012-05-01

The primary and most important oxidant in the atmosphere is the hydroxyl radical (OH). Currently OH sinks, particularly gas phase reactions, are poorly constrained. One way to characterize the overall sink of OH is to measure directly the ambient loss rate of OH, the total OH reactivity. To date direct measurements of total OH reactivity have been either performed using a Laser Induced Fluorescence (LIF) system ("pump-and-probe" or "flow reactor") or the Comparative Reactivity Method (CRM) with a Proton Transfer Reaction Mass Spectrometer (PTR-MS). Both techniques require large, complex and expensive detection systems. This study presents a feasibility assessment for CRM total OH reactivity measurements using a new detector, a Gas Chromatographic Photo-Ionization Detector (GC-PID). Such a system is smaller, more portable, less power consuming and less expensive than other total OH reactivity measurement techniques. Total OH reactivity is measured by the CRM using a competitive reaction between a reagent (here pyrrole) with OH alone and in the presence of atmospheric reactive molecules. The new CRM method for total OH reactivity has been tested with parallel measurements of the GC-PID and the previously validated PTR-MS as detector for the reagent pyrrole during laboratory experiments, plant chamber and boreal field studies. Excellent agreement of both detectors was found when the GC-PID was operated under optimum conditions. Time resolution (60-70 s), sensitivity (LOD 3-6 s-1) and overall uncertainty (25% in optimum conditions) for total OH reactivity were equivalent to PTR-MS based total OH reactivity measurements. One drawback of the GC-PID system was the steady loss of sensitivity and accuracy during intensive measurements lasting several weeks, and a possible toluene interference. Generally, the GC-PID system has been shown to produce closely comparable results to the PTR-MS and thus in suitable environments (e.g. forests) it presents a viably economical alternative for groups interested in total OH reactivity observations.

Total OH reactivity measurements using a new fast Gas Chromatographic Photo-Ionization Detector (GC-PID)

NASA Astrophysics Data System (ADS)

Nölscher, A. C.; Sinha, V.; Bockisch, S.; Klüpfel, T.; Williams, J.

2012-12-01

The primary and most important oxidant in the atmosphere is the hydroxyl radical (OH). Currently OH sinks, particularly gas phase reactions, are poorly constrained. One way to characterize the overall sink of OH is to measure directly the ambient loss rate of OH, the total OH reactivity. To date, direct measurements of total OH reactivity have been either performed using a Laser-Induced Fluorescence (LIF) system ("pump-and-probe" or "flow reactor") or the Comparative Reactivity Method (CRM) with a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS). Both techniques require large, complex and expensive detection systems. This study presents a feasibility assessment for CRM total OH reactivity measurements using a new detector, a Gas Chromatographic Photoionization Detector (GC-PID). Such a system is smaller, more portable, less power consuming and less expensive than other total OH reactivity measurement techniques. Total OH reactivity is measured by the CRM using a competitive reaction between a reagent (here pyrrole) with OH alone and in the presence of atmospheric reactive molecules. The new CRM method for total OH reactivity has been tested with parallel measurements of the GC-PID and the previously validated PTR-MS as detector for the reagent pyrrole during laboratory experiments, plant chamber and boreal field studies. Excellent agreement of both detectors was found when the GC-PID was operated under optimum conditions. Time resolution (60-70 s), sensitivity (LOD 3-6 s-1) and overall uncertainty (25% in optimum conditions) for total OH reactivity were similar to PTR-MS based total OH reactivity measurements. One drawback of the GC-PID system was the steady loss of sensitivity and accuracy during intensive measurements lasting several weeks, and a possible toluene interference. Generally, the GC-PID system has been shown to produce closely comparable results to the PTR-MS and thus in suitable environments (e.g. forests) it presents a viably economical alternative for groups interested in total OH reactivity observations.

Enhanced reactive oxygen species through direct copper sulfide nanoparticle-doxorubicin complexation

NASA Astrophysics Data System (ADS)

Li, Yajuan; Cupo, Michela; Guo, Liangran; Scott, Julie; Chen, Yi-Tzai; Yan, Bingfang; Lu, Wei

2017-12-01

CuS-based nanostructures loading the chemotherapeutic agent doxorubicin (DOX) exerted excellent cancer photothermal chemotherapy under multi-external stimuli. The DOX loading was generally designed through electrostatic interaction or chemical linkers. However, the interaction between DOX molecules and CuS nanoparticles has not been investigated. In this work, we use PEGylated hollow copper sulfide nanoparticles (HCuSNPs) to directly load DOX through the DOX/Cu2+ chelation process. Distinctively, the synthesized PEG-HCuSNPs-DOX release the DOX/Cu2+ complexes into surrounding environment, which generate significant reactive oxygen species (ROS) in a controlled manner by near-infrared laser. The CuS nanoparticle-mediated photothermal ablation facilitates the ROS-induced cancer cell killing effect. Our current work reveals a DOX/Cu2+-mediated ROS-enhanced cell-killing effect in addition to conventional photothermal chemotherapy through the direct CuS nanoparticle-DOX complexation.

A characterization and evaluation of coal liquefaction process streams. Quarterly technical progress report, October 1--December 31, 1994

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

Robbins, G.A.; Brandes, S.D.; Winschel, R.A.

1995-05-01

The objectives of this project are to support the DOE direct coal liquefaction process development program and to improve the useful application of analytical chemistry to direct coal liquefaction process development. Independent analyses by well-established methods will be obtained of samples produced in direct coal liquefaction processes under evaluation by DOE. Additionally, analytical instruments and techniques which are currently underutilized for the purpose of examining coal-derived samples will be evaluated. The data obtained from this study will be used to help guide current process development and to develop an improved data base on coal and coal liquids properties. A samplemore » bank will be established and maintained for use in this project and will be available for use by other researchers. The reactivity of the non-distillable resids toward hydrocracking at liquefaction conditions (i.e., resid reactivity) will be examined. From the literature and data experimentally obtained, a mathematical kinetic model of resid conversion will be constructed. It is anticipated that such a model will provide insights useful for improving process performance and thus the economics of direct coal liquefaction. During this quarter, analyses were completed on 65 process samples from representative periods of HRI Run POC-2 in which coal, coal/plastics, and coal/rubber were the feedstocks. A sample of the oil phase of the oil/water separator from HRI Run POC-1 was analyzed to determine the types and concentrations of phenolic compounds. Chemical analyses and microautoclave tests were performed to monitor the oxidation and measure the reactivity of the standard coal (Old Ben Mine No. 1) which has been used for the last six years to determine solvent quality of process oils analyzed in this and previous DOE contracts.« less

Chemical Methods for the Direct Detection and Labeling of S-Nitrosothiols

PubMed Central

Bechtold, Erika

2012-01-01

Abstract Significance: Posttranslational modification of proteins through phosphorylation, glycosylation, and oxidation adds complexity to the proteome by reversibly altering the structure and function of target proteins in a highly controlled fashion. Recent Advances: The study of reversible cysteine oxidation highlights a role for this oxidative modification in complex signal transduction pathways. Nitric oxide (NO), and its respective metabolites (including reactive nitrogen species), participates in a variety of these cellular redox processes, including the reversible oxidation of cysteine to S-nitrosothiols (RSNOs). RSNOs act as endogenous transporters of NO, but also possess beneficial effects independent of NO-related signaling, which suggests a complex and versatile biological role. In this review, we highlight the importance of RSNOs as a required posttranslational modification and summarize the current methods available for detecting S-nitrosation. Critical Issues: Given the limitations of these indirect detection methods, the review covers recent developments toward the direct detection of RSNOs by phosphine-based chemical probes. The intrinsic properties that dictate this phosphine/RSNO reactivity are summarized. In general, RSNOs (both small molecule and protein) react with phosphines to yield reactive S-substituted aza-ylides that undergo further reactions leading to stable RSNO-based adducts. Future Directions: This newly explored chemical reactivity forms the basis of a number of exciting potential chemical methods for protein RSNO detection in biological systems. Antioxid. Redox Signal. 17, 981–991. PMID:22356122

Large unexplained suite of chemically reactive compounds present in ambient air due to biomass fires.

PubMed

Kumar, V; Chandra, B P; Sinha, V

2018-01-12

Biomass fires impact global atmospheric chemistry. The reactive compounds emitted and formed due to biomass fires drive ozone and organic aerosol formation, affecting both air quality and climate. Direct hydroxyl (OH) Reactivity measurements quantify total gaseous reactive pollutant loadings and comparison with measured compounds yields the fraction of unmeasured compounds. Here, we quantified the magnitude and composition of total OH reactivity in the north-west Indo-Gangetic Plain. More than 120% increase occurred in total OH reactivity (28 s -1 to 64 s -1 ) and from no missing OH reactivity in the normal summertime air, the missing OH reactivity fraction increased to ~40 % in the post-harvest summertime period influenced by large scale biomass fires highlighting presence of unmeasured compounds. Increased missing OH reactivity between the two summertime periods was associated with increased concentrations of compounds with strong photochemical source such as acetaldehyde, acetone, hydroxyacetone, nitromethane, amides, isocyanic acid and primary emissions of acetonitrile and aromatic compounds. Currently even the most detailed state-of-the art atmospheric chemistry models exclude formamide, acetamide, nitromethane and isocyanic acid and their highly reactive precursor alkylamines (e.g. methylamine, ethylamine, dimethylamine, trimethylamine). For improved understanding of atmospheric chemistry-air quality-climate feedbacks in biomass-fire impacted atmospheric environments, future studies should include these compounds.

Electrical characteristics of thin Ta2O5 films deposited by reactive pulsed direct-current magnetron sputtering

NASA Astrophysics Data System (ADS)

Kim, J.-Y.; Nielsen, M. C.; Rymaszewski, E. J.; Lu, T.-M.

2000-02-01

Room temperature deposition of tantalum oxide films on metallized silicon substrates was investigated by reactive pulsed magnetron sputtering of Ta in an Ar/O2 ambient. The dielectric constant of the tantalum oxide ranged from 19 to 31 depending on the oxygen percentage [P(%)=PO2/(PO2+PAr)] used during sputtering. The leakage current density was less than 10 nA/cm2 at 0.5 MV/cm electric field and the dielectric breakdown field was greater than 3.8 MV/cm for P=60%. A charge storage as high as 3.3 μF/cm2 was achieved for 70-Å-thick film. Pulse frequency variation (from 20 to 200 kHz) did not give a significant effect in the electrical properties (dielectric constant or leakage current density) of the Ta2O5 films.

Distinct chromatin functional states correlate with HIV latency reactivation in infected primary CD4+ T cells.

PubMed

Battivelli, Emilie; Dahabieh, Matthew S; Abdel-Mohsen, Mohamed; Svensson, J Peter; Tojal Da Silva, Israel; Cohn, Lillian B; Gramatica, Andrea; Deeks, Steven; Greene, Warner C; Pillai, Satish K; Verdin, Eric

2018-05-01

Human immunodeficiency virus (HIV) infection is currently incurable, due to the persistence of latently infected cells. The 'shock and kill' approach to a cure proposes to eliminate this reservoir via transcriptional activation of latent proviruses, enabling direct or indirect killing of infected cells. Currently available latency-reversing agents (LRAs) have however proven ineffective. To understand why, we used a novel HIV reporter strain in primary CD4 + T cells and determined which latently infected cells are reactivatable by current candidate LRAs. Remarkably, none of these agents reactivated more than 5% of cells carrying a latent provirus. Sequencing analysis of reactivatable vs. non-reactivatable populations revealed that the integration sites were distinguishable in terms of chromatin functional states. Our findings challenge the feasibility of 'shock and kill', and suggest the need to explore other strategies to control the latent HIV reservoir. © 2018, Battivelli et al.

Overall cortisol, diurnal slope, and stress reactivity in psychosis: An experience sampling approach.

PubMed

Vaessen, Thomas; Kasanova, Zuzana; Hernaus, Dennis; Lataster, Johan; Collip, Dina; van Nierop, Martine; Myin-Germeys, Inez

2018-06-07

Results from experimental studies suggest that psychosis and psychosis liability are associated with increased cortisol levels and blunted cortisol reactivity, and that use of antipsychotics may reduce these aberrations. Here, we report on overall cortisol, diurnal slope, and cortisol stress reactivity in everyday life in psychosis and psychosis liability using the experience sampling method (ESM). Our sample consisted of individuals diagnosed with psychotic disorder currently on (MPD; n = 53) or off antipsychotic medication (NMPD; n = 20), first-degree relatives of psychotic patients (REL; n = 47), and healthy volunteers (HV; n = 67). Saliva samples were collected throughout the day on six consecutive days and analyzed for cortisol levels. Simultaneously, stressfulness of the current activity was assessed with ESM questionnaires. We found no group differences in overall cortisol level between groups, but REL had a steeper diurnal slope than HV; in MPD a trend was found in the same direction. Regarding reactivity to stressful activities, results indicated attenuation of the cortisol response in both patient groups compared to HV. These results do not confirm reports of increased cortisol levels in psychosis, but provide evidence of stress-related cortisol alterations in everyday life. Copyright © 2018 Elsevier Ltd. All rights reserved.

Spin-orbit torques and anisotropic magnetization damping in skyrmion crystals

NASA Astrophysics Data System (ADS)

Hals, Kjetil M. D.; Brataas, Arne

2014-02-01

The length scale of the magnetization gradients in chiral magnets is determined by the relativistic Dzyaloshinskii-Moriya interaction. Thus, even conventional spin-transfer torques are controlled by the relativistic spin-orbit coupling in these systems, and additional relativistic corrections to the current-induced torques and magnetization damping become important for a complete understanding of the current-driven magnetization dynamics. We theoretically study the effects of reactive and dissipative homogeneous spin-orbit torques and anisotropic damping on the current-driven skyrmion dynamics in cubic chiral magnets. Our results demonstrate that spin-orbit torques play a significant role in the current-induced skyrmion velocity. The dissipative spin-orbit torque generates a relativistic Magnus force on the skyrmions, whereas the reactive spin-orbit torque yields a correction to both the drift velocity along the current direction and the transverse velocity associated with the Magnus force. The spin-orbit torque corrections to the velocity scale linearly with the skyrmion size, which is inversely proportional to the spin-orbit coupling. Consequently, the reactive spin-orbit torque correction can be the same order of magnitude as the nonrelativistic contribution. More importantly, the dissipative spin-orbit torque can be the dominant force that causes a deflected motion of the skyrmions if the torque exhibits a linear or quadratic relationship with the spin-orbit coupling. In addition, we demonstrate that the skyrmion velocity is determined by anisotropic magnetization damping parameters governed by the skyrmion size.

Exposure of Bacterial Biofilms to Electrical Current Leads to Cell Death Mediated in Part by Reactive Oxygen Species

PubMed Central

Brinkman, Cassandra L.; Schmidt-Malan, Suzannah M.; Karau, Melissa J.; Greenwood-Quaintance, Kerryl; Hassett, Daniel J.; Mandrekar, Jayawant N.

2016-01-01

Bacterial biofilms may form on indwelling medical devices such as prosthetic joints, heart valves and catheters, causing challenging-to-treat infections. We have previously described the ‘electricidal effect’, in which bacterial biofilms are decreased following exposure to direct electrical current. Herein, we sought to determine if the decreased bacterial quantities are due to detachment of biofilms or cell death and to investigate the role that reactive oxygen species (ROS) play in the observed effect. Using confocal and electron microscopy and flow cytometry, we found that direct current (DC) leads to cell death and changes in the architecture of biofilms formed by Gram-positive and Gram-negative bacteria. Reactive oxygen species (ROS) appear to play a role in DC-associated cell death, as there was an increase in ROS-production by Staphylococcus aureus and Staphylococcus epidermidis biofilms following exposure to DC. An increase in the production of ROS response enzymes catalase and superoxide dismutase (SOD) was observed for S. aureus, S. epidermidis and Pseudomonas aeruginosa biofilms following exposure to DC. Additionally, biofilms were protected from cell death when supplemented with antioxidants and oxidant scavengers, including catalase, mannitol and Tempol. Knocking out SOD (sodAB) in P. aeruginosa led to an enhanced DC effect. Microarray analysis of P. aeruginosa PAO1 showed transcriptional changes in genes related to the stress response and cell death. In conclusion, the electricidal effect results in death of bacteria in biofilms, mediated, at least in part, by production of ROS. PMID:27992529

The relationship between personality disorder traits and reactive versus proactive motivation for aggression.

PubMed

Lobbestael, Jill; Cima, Maaike; Lemmens, Anke

2015-09-30

There is a strong link between personality disorders (PDs) and aggression. This is reflected in high prevalence rates of PD diagnoses in forensic samples, and in several diagnostic criteria of PDs directly referring to elevated levels of aggression. Aggression can stem from two distinct types of motivation; reactive or impulsive aggression that serves as a defensive reaction to provocation, and proactive or premeditated aggression used to gain extrinsic benefits. Although some clinical conditions like antisocial, borderline, and narcissistic PDs or PD traits, have been empirically linked to reactive and/or proactive aggression, the current study pioneers assessing the relationship between reactive and proactive aggression and traits of all 10 PDs. A mixed sample of patient and non-patient (N=238) participants were administered with the SCID II to assess the level of PD traits; they also completed the Reactive Proactive Questionnaire to determine levels of reactive and proactive aggression. Results showed that paranoid PD traits were positively related to reactive aggression, whereas proactive aggression was uniquely related to antisocial PD traits. This highlights the importance of differentiating between distinct motivations for aggression in PD samples. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Age Differences in Affective and Cardiovascular Responses to a Negative Social Interaction: The Role of Goals, Appraisals, and Emotion Regulation

ERIC Educational Resources Information Center

Luong, Gloria; Charles, Susan T.

2014-01-01

Older adults often report less affective reactivity to interpersonal tensions than younger individuals, but few studies have directly investigated mechanisms explaining this effect. The current study examined whether older adults' differential endorsement of goals, appraisals, and emotion regulation strategies (i.e., conflict…

Low temperature fabrication of VO x thin films for uncooled IR detectors by direct current reactive magnetron sputtering method

NASA Astrophysics Data System (ADS)

Dai, Jun; Wang, Xingzhi; He, Shaowei; Huang, Ying; Yi, Xinjian

2008-03-01

Vanadium oxide films have been fabricated on Si3N4-film-coated silicon substrates by direct current reactive magnetron sputtering method. Conditions of deposition are optimized making use of parameters such as sputtering time, dc power, oxygen partial pressure and substrate temperature. X-ray diffraction indicates that the film is a mixture of VO2, V2O3, and V3O5. Four-probe measurement shows that the VOx thin film owns high temperature coefficient of resistance (TCR ∼-2.05%/°C) and suitable square resistance 18.40 kΩ/□ (measured at 25 °C), indicating it is a well candidate material for uncooled IR detectors. In addition, IR absorption in the wavelength of 2-16 μm has been characterized. It is worth noting that the films are sputtered at a relatively low temperature of 210 °C in a controlled Ar/O2 atmosphere. Compared to traditional craft, this method needs no post-anneal at high temperature (400-500 °C).

The advancement of chemical cross-linking and mass spectrometry for structural proteomics: from single proteins to protein interaction networks.

PubMed

Sinz, Andrea

2014-12-01

During the last 15 years, chemical cross-linking combined with mass spectrometry (MS) and computational modeling has advanced from investigating 3D-structures of isolated proteins to deciphering protein interaction networks. In this article, the author discusses the advent, the development and the current status of the chemical cross-linking/MS strategy in the context of recent technological developments. A direct way to probe in vivo protein-protein interactions is by site-specific incorporation of genetically encoded photo-reactive amino acids or by non-directed incorporation of photo-reactive amino acids. As the chemical cross-linking/MS approach allows the capture of transient and weak interactions, it has the potential to become a routine technique for unraveling protein interaction networks in their natural cellular environment.

Controlled, Site-Specific Functionalization of Carbon Nanotubes with Diazonium Salts

NASA Technical Reports Server (NTRS)

Tour, James M.

2013-01-01

This work uses existing technologies to prepare a crossbar architecture of nano tubes, wherein one nanotube is fixed to a substrate, and a second nanotube is suspended a finite distance above. Both nano tubes can be individually addressed electrically. Application of opposite potentials to the two tubes causes the top tube to deform and to essentially come into contact with the lower tube. Contact here refers not to actual, physical contact, but rather within an infinitesimally small distance referred to as van der Walls contact, in which the entities may influence each other on a molecular and electronic scale. First, the top tube is physically deformed, leading to a potentially higher chemical reactivity at the point of deformation, based on current understanding of the effects of curvature strain on reactivity. This feature would allow selective functionalization at the junction via reaction with diazonium salts. Secondly, higher potential is achieved at the point of "cross" between the tubes. In a pending patent application, a method is claimed for directed self-assembly of molecular components onto the surface of metal or conductive materials by application of potential to the metal or conductive surface. In another pending patent application, a method is claimed for attaching molecules to the surface of nanotubes via the use of reactive diazonium salts. In the present invention, the directed functionalization of the crossed-nanotube junctions by applying a potential to the ends of the nanotubes in the presence of reactive diazonium slats, or other reactive molecular species is claimed. The diazonium salts are directed by the potential existing at the junction to react with the surface of the nanotube, thus placing functional molecular components at the junctions. The crossed nano tubes therefore provide a method of directly addressing the functionalized molecules, which have been shown to function as molecular switches, molecular wires, and in other capacities and uses. Site-specific functionalization may enable the use of nanotubes in molecular electronic applications because device functionality is critical at the cross points.

Startle Potentiation to Uncertain Threat as a Psychophysiological Indicator of Fear-based Psychopathology: An Examination across Multiple Internalizing Disorders

PubMed Central

Gorka, Stephanie M.; Lieberman, Lynne; Shankman, Stewart A.; Phan, K. Luan

2016-01-01

Heightened reactivity to uncertain threat (U-threat) is an important individual difference factor that may characterize fear-based internalizing psychopathologies (IPs) and distinguish them from distress/misery IPs. To date, however, the majority of existing research examining reactivity to U-threat has been within individuals with panic disorder and major depressive disorder (MDD) and no prior study has directly tested this hypothesis across multiple IPs. The current study therefore explored whether heightened reactivity to U-threat is a psychophysiological indicator of fear-based psychopathology across five groups: current 1) social anxiety disorder (SAD), 2) specific phobia (SP), 3) generalized anxiety disorder (GAD), 4) MDD, and 5) individuals with no history of psychopathology (controls). All 160 adults completed a well-validated threat-of-shock task designed to probe responses to predictable (P-) and U-threat. Startle eyeblink potentiation was recorded as an index of aversive arousal. Results indicated that individuals with SAD and SP evidenced greater startle potentiation to U-threat, but not P-threat, relative to individuals with GAD, MDD and controls (who did not differ). The current findings, along with the prior panic disorder and MDD literature, suggest that heightened reactivity to U-threat is a psychophysiological indicator of fear-based disorders and could represent a neurobiological organizing principle for internalizing psychopathology. The findings also suggest that individuals with fear disorders generally display a hypersensitivity to uncertain aversive events, which could contribute to their psychopathology. PMID:27868423

Compensation for Harmonic Currents and Reactive Power in Wind Power Generation System using PWM Inverter

NASA Astrophysics Data System (ADS)

Shinohara, Katsuji; Shinhatsubo, Kurato; Iimori, Kenichi; Yamamoto, Kichiro; Saruban, Takamichi; Yamaemori, Takahiro

In recent year, consciousness of environmental problems is enhancing, and the price of the electric power purchased by an electric power company is established expensive for the power plant utilizing the natural energy. So, the introduction of the wind power generation is promoted in Japan. Generally, squirrel-cage induction machines are widely used as a generator in wind power generation system because of its small size, lightweight and low-cost. However, the induction machines do not have a source of excitation. Thus, it causes the inrush currents and the instantaneous voltage drop when the generator is directly connected to a power grid. To reduce the inrush currents, an AC power regulator is used. Wind power generations are frequently connected to and disconnected from the power grid. However, when the inrush currents are reduced, harmonic currents are caused by phase control of the AC power regulator. And the phase control of AC power regulator cannot control the power factor. Therefore, we propose the use of the AC power regulator to compensate for the harmonic currents and reactive power in the wind power generation system, and demonstrate the validity of its system by simulated and experimental results.

Ligand-accelerated non-directed C-H functionalization of arenes.

PubMed

Wang, Peng; Verma, Pritha; Xia, Guoqin; Shi, Jun; Qiao, Jennifer X; Tao, Shiwei; Cheng, Peter T W; Poss, Michael A; Farmer, Marcus E; Yeung, Kap-Sun; Yu, Jin-Quan

2017-11-22

The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.

Ligand-accelerated non-directed C-H functionalization of arenes

NASA Astrophysics Data System (ADS)

Wang, Peng; Verma, Pritha; Xia, Guoqin; Shi, Jun; Qiao, Jennifer X.; Tao, Shiwei; Cheng, Peter T. W.; Poss, Michael A.; Farmer, Marcus E.; Yeung, Kap-Sun; Yu, Jin-Quan

2017-11-01

The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.

Understanding the link between exposure to violence and aggression in justice-involved adolescents.

PubMed

Wall Myers, Tina D; Salcedo, Abigail; Frick, Paul J; Ray, James V; Thornton, Laura C; Steinberg, Laurence; Cauffman, Elizabeth

2018-05-01

The current study advanced research on the link between community violence exposure and aggression by comparing the effects of violence exposure on different functions of aggression and by testing four potential (i.e., callous-unemotional traits, consideration of others, impulse control, and anxiety) mediators of this relationship. Analyses were conducted in an ethnically/racially diverse sample of 1,216 male first-time juvenile offenders (M = 15.30 years, SD = 1.29). Our results indicated that violence exposure had direct effects on both proactive and reactive aggression 18 months later. The predictive link of violence exposure to proactive aggression was no longer significant after controlling for proactive aggression at baseline and the overlap with reactive aggression. In contrast, violence exposure predicted later reactive aggression even after controlling for baseline reactive aggression and the overlap with proactive aggression. Mediation analyses of the association between violence exposure and reactive aggression indicated indirect effects through all potential mediators, but the strongest indirect effect was through impulse control. The findings help to advance knowledge on the consequences of community violence exposure on justice-involved youth.

Direct and Indirect Effects of PM on the Cardiovascular System

PubMed Central

Nelin, Timothy D.; Joseph, Allan M.; Gorr, Matthew W.; Wold, Loren E.

2011-01-01

Human exposure to particulate matter (PM) elicits a variety of responses on the cardiovascular system through both direct and indirect pathways. Indirect effects of PM on the cardiovascular system are mediated through the autonomic nervous system, which controls heart rate variability, and inflammatory responses, which augment acute cardiovascular events and atherosclerosis. Recent research demonstrates that PM also affects the cardiovascular system directly by entry into the systemic circulation. This process causes myocardial dysfunction through mechanisms of reactive oxygen species production, calcium ion interference, and vascular dysfunction. In this review, we will present key evidence in both the direct and indirect pathways, suggest clinical applications of the current literature, and recommend directions for future research. PMID:22119171

Levels of craving influence psychological challenge and physiological reactivity.

PubMed

Frings, Daniel; Eskisan, Guleser; Spada, Marcantonio M; Albery, Ian P

2015-01-01

Behavioural and cognitive pathways that lead to the activation and escalation of craving have been studied extensively. Conversely, limited efforts have been directed towards understanding how craving relates to motivational systems and neuroendocrine responses. These can be understood using the biopsychosocial model of challenge and threat. In the current study, forty participants with varying levels of chocolate craving undertook two word searches, with the prospect of winning a piece of chocolate. Amongst those with high levels of craving, participation in this task led to motivational states of challenge relative to those with lower levels. This was reflected by changes in cardiac reactivity driven by differences in sympathetic-adrenal-medullar and hypothalamic-pituitary-adrenal axis activation. This finding suggests that craving can be associated with states of motivational challenge and thus affect cardiac reactivity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Power flow controller with a fractionally rated back-to-back converter

DOEpatents

Divan, Deepakraj M.; Kandula, Rajendra Prasad; Prasai, Anish

2016-03-08

A power flow controller with a fractionally rated back-to-back (BTB) converter is provided. The power flow controller provide dynamic control of both active and reactive power of a power system. The power flow controller inserts a voltage with controllable magnitude and phase between two AC sources at the same frequency; thereby effecting control of active and reactive power flows between the two AC sources. A transformer may be augmented with a fractionally rated bi-directional Back to Back (BTB) converter. The fractionally rated BTB converter comprises a transformer side converter (TSC), a direct-current (DC) link, and a line side converter (LSC). By controlling the switches of the BTB converter, the effective phase angle between the two AC source voltages may be regulated, and the amplitude of the voltage inserted by the power flow controller may be adjusted with respect to the AC source voltages.

Effects of prenatal depressive symptoms on maternal and infant cortisol reactivity.

PubMed

Braithwaite, Elizabeth C; Murphy, Susannah E; Ramchandani, Paul G

2016-08-01

Prenatal depression is associated with adverse offspring outcomes, and the prevailing mechanistic theory to account for mood-associated effects implicates alterations of the maternal and foetal hypothalamic-pituitary adrenal (HPA) axes. Recent research suggests that depression may be associated with a failure to attenuate cortisol reactivity during early pregnancy. The aim of the current study is to investigate whether this effect continues into mid and late gestation. A further aim is to test whether maternal prenatal cortisol reactivity directly predicts infant cortisol reactivity. One hundred three pregnant women were recruited during either the second or third trimester. Depressive symptoms were assessed by self-report, and maternal salivary cortisol responses to a stressor (infant distress film) were measured. Approximately 2 months after birth, mothers (n = 88) reported postnatal depression and infant salivary cortisol responses to inoculation were measured. Prenatal depression was not associated with cortisol reactivity to acute stress in mid and late pregnancy. Similarly, neither prenatal depression nor maternal prenatal cortisol reactivity predicted infant cortisol reactivity to inoculation at 2 months. If the effects of prenatal depression on foetal and infant development are mediated by alterations of the maternal and foetal HPA axes, then early pregnancy may be a particularly vulnerable period. Alternatively, changes to HPA reactivity may not be as central to this association as previously thought.

Model-free simulations of turbulent reactive flows

NASA Technical Reports Server (NTRS)

Givi, Peyman

1989-01-01

The current computational methods for solving transport equations of turbulent reacting single-phase flows are critically reviewed, with primary attention given to those methods that lead to model-free simulations. In particular, consideration is given to direct numerical simulations using spectral (Galerkin) and pseudospectral (collocation) methods, spectral element methods, and Lagrangian methods. The discussion also covers large eddy simulations and turbulence modeling.

Direct Characterization of a Reactive Lattice-Confined Ru 2 Nitride by Photocrystallography

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

Das, Anuvab; Reibenspies, Joseph H.; Chen, Yu-Sheng

2017-02-16

Reactive metal–ligand (M–L) multiply bonded complexes are ubiquitous intermediates in redox catalysis and have thus been long-standing targets of synthetic chemistry. The intrinsic reactivity of mid-to-late M–L multiply bonded complexes renders these structures challenging to isolate and structurally characterize. Although synthetic tuning of the ancillary ligand field can stabilize M–L multiply bonded complexes and result in isolable complexes, these efforts inevitably attenuate the reactivity of the M–L multiple bond. Here, we report the first direct characterization of a reactive Ru2 nitride intermediate by photocrystallography. Photogeneration of reactive M–L multiple bonds within crystalline matrices supports direct characterization of these critical intermediatesmore » without synthetic derivatization.« less

Startle potentiation to uncertain threat as a psychophysiological indicator of fear-based psychopathology: An examination across multiple internalizing disorders.

PubMed

Gorka, Stephanie M; Lieberman, Lynne; Shankman, Stewart A; Phan, K Luan

2017-01-01

Heightened reactivity to uncertain threat (U-threat) is an important individual difference factor that may characterize fear-based internalizing psychopathologies (IPs) and distinguish them from distress/misery IPs. To date, however, the majority of existing research examining reactivity to U-threat has been within individuals with panic disorder and major depressive disorder (MDD) and no prior study has directly tested this hypothesis across multiple IPs. The current study therefore explored whether heightened reactivity to U-threat is a psychophysiological indicator of fear-based psychopathology across 5 groups: current (a) social anxiety disorder (SAD); (b) specific phobia (SP); (c) generalized anxiety disorder (GAD); (d) MDD; and (c) individuals with no history of psychopathology (controls). All 160 adults completed a well-validated threat-of-shock task designed to probe responses to predictable (P-) and U-threat. Startle eyeblink potentiation was recorded as an index of aversive arousal. Results indicated that individuals with SAD and SP evidenced greater startle potentiation to U-threat, but not P-threat, relative to individuals with GAD, MDD, and controls (who did not differ). The current findings, along with the prior panic disorder and MDD literature, suggest that heightened reactivity to U-threat is a psychophysiological indicator of fear-based disorders and could represent a neurobiological organizing principle for internalizing psychopathology. The findings also suggest that individuals with fear disorders generally display a hypersensitivity to uncertain aversive events, which could contribute to their psychopathology. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Reactive Molecular Dynamics Simulations to Understand Mechanical Response of Thaumasite under Temperature and Strain Rate Effects.

PubMed

Hajilar, Shahin; Shafei, Behrouz; Cheng, Tao; Jaramillo-Botero, Andres

2017-06-22

Understanding the structural, thermal, and mechanical properties of thaumasite is of great interest to the cement industry, mainly because it is the phase responsible for the aging and deterioration of civil infrastructures made of cementitious materials attacked by external sources of sulfate. Despite the importance, effects of temperature and strain rate on the mechanical response of thaumasite had remained unexplored prior to the current study, in which the mechanical properties of thaumasite are fully characterized using the reactive molecular dynamics (RMD) method. With employing a first-principles based reactive force field, the RMD simulations enable the description of bond dissociation and formation under realistic conditions. From the stress-strain curves of thaumasite generated in the x, y, and z directions, the tensile strength, Young's modulus, and fracture strain are determined for the three orthogonal directions. During the course of each simulation, the chemical bonds undergoing tensile deformations are monitored to reveal the bonds responsible for the mechanical strength of thaumasite. The temperature increase is found to accelerate the bond breaking rate and consequently the degradation of mechanical properties of thaumasite, while the strain rate only leads to a slight enhancement of them for the ranges considered in this study.

Investigation of ambient OH reactivity at a receptor site impacted by industrial, urban and marine emissions: Identification of missing OH reactivity

NASA Astrophysics Data System (ADS)

Dusanter, Sébastien; Michoud, Vincent; Léonardis, Thierry; Locoge, Nadine; Riffault, Véronique; Zhang, Shouwen

2015-04-01

The hydroxyl radical (OH), the main daytime oxidant in the troposphere, plays a key role in atmospheric chemistry. OH initiates the oxidation of most of the trace gases, including Volatile Organic Compounds (VOC), leading to the formation of harmful secondary pollutants such as ozone and secondary organic aerosols. VOCs are directly emitted by a large number of natural and anthropogenic sources and can be formed photochemically. It is expected that several thousand VOCs could be present in the troposphere at ppt-ppb levels (Goldstein and Galbally, ES&T, 2007), making exhaustive measurements of VOCs currently unfeasible with common analytical techniques. In this context, measuring the total sink of OH, so called total OH reactivity, can provide insights into the reactivity of unmeasured trace gases to test the completeness of VOC measurements during field campaigns. A Comparative Reactivity Method (CRM) instrument was deployed in Dunkirk (France) to measure ambient OH reactivity during July 2014. An objective of this field campaign was to investigate the OH reactivity budget in different types of air masses, characterized by industrial, urban, and marine emissions, as well as different photochemical ages. Collocated measurements of non-methane hydrocarbons, oxygenated VOCs, and inorganic gases were also performed. OH reactivity measurements ranged from the detection limit of 3 s-1 up to 90 s-1, with a campaign average of approximately 14 s-1. Large discrepancies were observed between OH reactivity measurements and values calculated from measured trace gases, highlighting the presence of unmeasured reactive compounds. In this presentation, the measured and missing OH reactivity will be discussed regarding air mass origins and compositions. We will also present a novel approach that was implemented on the CRM instrument to identify part of the observed missing OH reactivity.

Reactivity of young chars via energetic distribution measurements

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

Calo, J.M.; Lilly, W.D.

1991-01-01

The current project is directed at developing related techniques for the characterization and prediction/correlation of the reactivity of young'' chars to steam and oxygen. Of particular interest is mapping of the reactivity behavior of the resultant chars, as revealed by the energetic heterogeneity of the complexes with char preparation conditions; i.e., heating rate and ultimate temperature. In this first quarterly technical progress report we present the background of the project and the research program for the proposed investigations. The following work was accomplished on the experimental apparatus: a new set of electronics for the UTi quadrupole mass spectrometer head wasmore » purchased and delivered. The Temperature Programmed Desorption (TPD) System was moved to another laboratory and interfaced with the mass spectrometer system. A Polycold{trademark} freon refrigeration system was repaired and interfaced with the vacuum system for the TPD apparatus. It will be used to cool the diffusion pump trap. 60 refs.« less

Measuring Multiple Resistances Using Single-Point Excitation

NASA Technical Reports Server (NTRS)

Hall, Dan; Davies, Frank

2009-01-01

In a proposed method of determining the resistances of individual DC electrical devices connected in a series or parallel string, no attempt would be made to perform direct measurements on individual devices. Instead, (1) the devices would be instrumented by connecting reactive circuit components in parallel and/or in series with the devices, as appropriate; (2) a pulse or AC voltage excitation would be applied at a single point on the string; and (3) the transient or AC steady-state current response of the string would be measured at that point only. Each reactive component(s) associated with each device would be distinct in order to associate a unique time-dependent response with that device.

From Anomalies to Essential Scientific Revolution? Intrinsic Brain Activity in the Light of Kuhn's Philosophy of Science.

PubMed

Havlík, Marek

2017-01-01

The first step toward a modern understanding of fMRI resting brain activity was made by Bharat Biswal in 1995. This surprising, and at first rejected, discovery is now associated with many resting state networks, notably the famous default mode network (DMN). Resting state activity and DMN significantly reassessed our traditional beliefs and conventions about the functioning of the brain. For the majority of the twentieth century, neuroscientists assumed that the brain is mainly the "reactive engine" to the environment operating mostly through stimulation. This "reactive convention" was very influential and convenient for the goals of twentieth century neuroscience-non-invasive functional localization based on stimulation. Largely unchallenged, "reactive convention" determined the direction of scientific research for a long time and became the "reactive paradigm" of the twentieth century. Resting state activity brought knowledge that was quite different of the "reactive paradigm." Current research of the DMN, probably the best known resting state network, leads to entirely new observations and conclusions, which were not achievable from the perspective of the "reactive paradigm." This shift from reactive activity to resting state activity of the brain is accompanied by an important question: "Can resting state activity be considered a scientific revolution and the new paradigm of neuroscience, or is it only significant for one branch of neuroscience, such as fMRI?"

Distributed Patterns of Reactivation Predict Vividness of Recollection.

PubMed

St-Laurent, Marie; Abdi, Hervé; Buchsbaum, Bradley R

2015-10-01

According to the principle of reactivation, memory retrieval evokes patterns of brain activity that resemble those instantiated when an event was first experienced. Intuitively, one would expect neural reactivation to contribute to recollection (i.e., the vivid impression of reliving past events), but evidence of a direct relationship between the subjective quality of recollection and multiregional reactivation of item-specific neural patterns is lacking. The current study assessed this relationship using fMRI to measure brain activity as participants viewed and mentally replayed a set of short videos. We used multivoxel pattern analysis to train a classifier to identify individual videos based on brain activity evoked during perception and tested how accurately the classifier could distinguish among videos during mental replay. Classification accuracy correlated positively with memory vividness, indicating that the specificity of multivariate brain patterns observed during memory retrieval was related to the subjective quality of a memory. In addition, we identified a set of brain regions whose univariate activity during retrieval predicted both memory vividness and the strength of the classifier's prediction irrespective of the particular video that was retrieved. Our results establish distributed patterns of neural reactivation as a valid and objective marker of the quality of recollection.

Association between problematic alcohol use and reactivity to uncertain threat in two independent samples

PubMed Central

Gorka, Stephanie M.; Lieberman, Lynne; Phan, K. Luan; Shankman, Stewart A.

2016-01-01

Background Recent laboratory studies have shown that acute alcohol intoxication selectively and effectively dampens aversive responding to an uncertain threat. An emerging hypothesis is that individuals who exhibit heightened reactivity to an uncertain threat may be especially motivated to use alcohol to dampen their distress, setting the stage for negative reinforcement processes to drive excessive alcohol use. However, no study to date has directly examined whether current problematic drinkers exhibit heightened reactivity to an uncertain threat as would be expected. Methods The present study was therefore designed to examine the association between current problematic alcohol use and reactivity to an uncertain threat during sobriety in two, independent samples. In Study 1 (n = 221) and Study 2 (n = 74), adult participants completed the same well-validated threat-of-shock task which separately probes responses to temporally predictable and unpredictable threat. Startle potentiation was measured as an index of aversive responding. Problematic alcohol use was defined as number of binge episodes within the past 30 days in Study 1 and total scores on a self-report measure of hazardous drinking in Study 2. Results As hypothesized, across both studies greater levels of problematic drinking were associated with greater startle potentiation to an unpredictable threat. In Study 2, hazardous drinking scores were also positively associated with startle potentiation to predictable threat. Conclusions The findings are notably consistent with the notion that heightened reactivity to an uncertain threat is an important individual difference factor associated with the onset and/or maintenance of problematic drinking behaviors and may therefore be a novel prevention and intervention target. PMID:27173662

Comparative Studies on Dyeability with Direct, Acid and Reactive Dyes after Chemical Modification of Jute with Mixed Amino Acids Obtained from Extract of Waste Soya Bean Seeds

NASA Astrophysics Data System (ADS)

Bhaumik, Nilendu Sekhar; Konar, Adwaita; Roy, Alok Nath; Samanta, Ashis Kumar

2017-12-01

Jute fabric was treated with mixed natural amino acids obtained from waste soya bean seed extract for chemical modification of jute for its cataionization and to enhance its dyeability with anionic dyes (like direct, reactive and acid dye) as well enabling soya modified jute for salt free dyeing with anionic reactive dyes maintaining its eco-friendliness. Colour interaction parameters including surface colour strength were assessed and compared for both bleached and soya-modified jute fabric for reactive dyeing and compared with direct and acid dye. Improvement in K/S value (surface colour strength) was observed for soya-modified jute even in absence of salt applied in dye bath for reactive dyes as well as for direct and acid dyes. In addition, reactive dye also shows good dyeability even in acid bath in salt free conditions. Colour fastness to wash was evaluated for bleached and soya-modified jute fabric after dyeing with direct, acid and reactive dyes are reported. Treatment of jute with soya-extracted mixed natural amino acids showed anchoring of some amino/aldemine groups on jute cellulosic polymer evidenced from Fourier Transform Infra-Red (FTIR) Spectroscopy. This amino or aldemine group incorporation in bleached jute causes its cationization and hence when dyed in acid bath for reactive dye (instead of conventional alkali bath) showed dye uptake for reactive dyes. Study of surface morphology by Scanning Electron Microscopy (SEM) of said soya-modified jute as compared to bleached jute was studied and reported.

Moderating Effects of Gender on Outcomes Associated with Stressful Life Events Among Elementary School-Age Youth.

PubMed

Brown, Shaquanna; Fite, Paula J; Poquiz, Jonathan

2016-08-01

Stressful life events have been associated with child and adolescent maladjustment, including elevated levels of aggression and anxiety (Attar et al. in J Clin Child Psychol 23:391-400, 1994; Fox et al. in J Adolesc 33:43-54, 2010). However, gender specific outcomes associated with stressful life events among elementary school-age youth are less known. Accordingly, the current study examined the role of gender in the associations between stressful life events and anxiety and proactive and reactive aggression. Participants included 294 elementary school-age children (M = 8.71, SD = 1.17, 50.7 % male). Regression analyses indicated that stressful life events were positively associated with anxiety and reactive, but not proactive, aggression. There were no gender differences with regard to the associations with anxiety symptoms or proactive aggression. However, gender moderated the association between stressful life events and reactive aggression, such that stressful life events were only positively associated with reactive aggression for boys. Future directions and implications of this research are presented.

Reactivation of Rate Remapping in CA3.

PubMed

Schwindel, C Daniela; Navratilova, Zaneta; Ali, Karim; Tatsuno, Masami; McNaughton, Bruce L

2016-09-07

The hippocampus is thought to contribute to episodic memory by creating, storing, and reactivating patterns that are unique to each experience, including different experiences that happen at the same location. Hippocampus can combine spatial and contextual/episodic information using a dual coding scheme known as "global" and "rate" remapping. Global remapping selects which set of neurons can activate at a given location. Rate remapping readjusts the firing rates of this set depending on current experience, thus expressing experience-unique patterns at each location. But can the experience-unique component be retrieved spontaneously? Whereas reactivation of recent, spatially selective patterns in hippocampus is well established, it is never perfect, raising the issue of whether the experiential component might be absent. This question is key to the hypothesis that hippocampus can assist memory consolidation by reactivating and broadcasting experience-specific "index codes" to neocortex. In CA3, global remapping exhibits attractor-like dynamics, whereas rate remapping apparently does not, leading to the hypothesis that only the former can be retrieved associatively and casting doubt on the general consolidation hypothesis. Therefore, we studied whether the rate component is reactivated spontaneously during sleep. We conducted neural ensemble recordings from CA3 while rats ran on a circular track in different directions (in different sessions) and while they slept. It was shown previously that the two directions of running result in strong rate remapping. During sleep, the most recent rate distribution was reactivated preferentially. Therefore, CA3 can retrieve patterns spontaneously that are unique to both the location and the content of recent experience. The hippocampus is required for memory of events and their spatial contexts. The primary correlate of hippocampal activity is location in space, but multiple memories can occur in the same location. To be useful for distinguishing these memories, the hippocampus must be able, not only to express, but also to retrieve both spatial and nonspatial information about events. Whether it can retrieve nonspatial information has been challenged recently. We exposed rats to two different experiences (running in different directions) in the same locations and showed that even the nonspatial components of hippocampal cell firing are reactivated spontaneously during sleep, supporting the conclusion that both types of information about a recent experience can be retrieved. Copyright © 2016 the authors 0270-6474/16/369342-09$15.00/0.

Real-time imaging of oxidative and nitrosative stress in the liver of live animals for drug-toxicity testing

PubMed Central

Shuhendler, Adam J.; Pu, Kanyi; Cui, Lina; Uetrecht, Jack P.

2014-01-01

Current drug-safety assays for hepatotoxicity rely on biomarkers with low predictive power. The production of radical species, specifically reactive oxygen species (ROS) and reactive nitrogen species (RNS), has been proposed as an early unifying event linking the bioactivation of drugs to hepatotoxicity and as a more direct and mechanistic indicator of hepatotoxic potential. Here we present a nanosensor for rapid, real-time in vivo imaging of drug-induced ROS and RNS for direct evaluation of acute hepatotoxicity. By combining fluorescence resonance energy transfer (FRET) and chemiluminescence resonance energy transfer (CRET), our semiconducting polymer–based nanosensor simultaneously and differentially detects RNS and ROS using two optically independent channels. Drug-induced hepatotoxicity and its remediation are imaged longitudinally in mice following systemic challenge with acetaminophen or isoniazid. Dose-dependent ROS and RNS activity is detected in the liver within minutes of drug challenge, preceding histological changes, protein nitration and DNA double strand break induction. PMID:24658645

A test of the facultative calibration/reactive heritability model of extraversion

PubMed Central

Haysom, Hannah J.; Mitchem, Dorian G.; Lee, Anthony J.; Wright, Margaret J.; Martin, Nicholas G.; Keller, Matthew C.; Zietsch, Brendan P.

2015-01-01

A model proposed by Lukaszewski and Roney (2011) suggests that each individual’s level of extraversion is calibrated to other traits that predict the success of an extraverted behavioural strategy. Under ‘facultative calibration’, extraversion is not directly heritable, but rather exhibits heritability through its calibration to directly heritable traits (“reactive heritability”). The current study uses biometrical modelling of 1659 identical and non-identical twins and their siblings to assess whether the genetic variation in extraversion is calibrated to variation in facial attractiveness, intelligence, height in men and body mass index (BMI) in women. Extraversion was significantly positively correlated with facial attractiveness in both males (r=.11) and females (r=.18), but correlations between extraversion and the other variables were not consistent with predictions. Further, twin modelling revealed that the genetic variation in facial attractiveness did not account for a substantial proportion of the variation in extraversion in either males (2.4%) or females (0.5%). PMID:26880866

Characterization of the MEMS Directional Sound Sensor Fabricated Using the SOIMUMPS Process

DTIC Science & Technology

2008-06-01

ABBREVIATIONS AND ACRONYMS ASW Anti- Submarine Warfare AUV Autonomous Underwater Vehicle DRIE Deep Reactive Ion Etching FAS Federation of American...as the frequency diverges from the resonant frequency (2980 Hz ) of the sensor. This analysis points out some disadvantages of the current set up of...sound sensor has important military applications, in particular to anti- submarine warfare (ASW). The sensor considered in this thesis is modeled on

Immunotherapy for Type 1 Diabetes: Why Do Current Protocols Not Halt the Underlying Disease Process?

PubMed

Kolb, Hubert; von Herrath, Matthias

2017-02-07

T cell-directed immunosuppression only transiently delays the loss of β cell function in recent-onset type 1 diabetes. We argue here that the underlying disease process is carried by innate immune reactivity. Inducing a non-polarized functional state of local innate immunity will support regulatory T cell development and β cell proliferation. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of Several New and Currently Available Oxime Cholinesterase Reactivators on Tabun-intoxicated Rats

PubMed Central

Karasova, Jana Zdarova; Kassa, Jiri; Jung, Young-Sik; Musilek, Kamil; Pohanka, Miroslav; Kuca, Kamil

2008-01-01

The therapeutical efficacies of eleven oxime-based acetylcholinesterase reactivators were compared in an in vivo (rat model) study of treatment of intoxication caused by tabun. In this group there were some currently available oximes (obidoxime, trimedoxime and HI-6) and the rest were newly synthesized compounds. The best reactivation efficacy for acetylcholinesterase in blood (expressed as percent of reactivation) among the currently available oximes was observed after administration of trimedoxime (16%) and of the newly synthesized K127 (22432) (25%). The reactivation of butyrylcholinesterase in plasma was also studied; the best reactivators were trimedoxime, K117 (22435), and K127 (22432), with overall reactivation efficacies of approximately 30%. Partial protection of brain ChE against tabun inhibition was observed after administration of trimedoxime (acetylcholinesterase 20%; butyrylcholinesterase 30%) and obidoxime (acetylcholinesterase 12%; butyrylcholinesterase 16%). PMID:19330072

Deposition of vanadium oxide films by direct-current magnetron reactive sputtering

NASA Astrophysics Data System (ADS)

Kusano, E.; Theil, J. A.; Thornton, John A.

1988-06-01

It is demonstrated here that thin films of vanadium oxide can be deposited at modest substrate temperatures by dc reactive sputtering from a vanadium target in an O2-Ar working gas using a planar magnetron source. Resistivity ratios of about 5000 are found between a semiconductor phase with a resistivity of about 5 Ohm cm and a metallic phase with a resistivity of about 0.001 Ohm cm for films deposited onto borosilicate glass substrates at about 400 C. X-ray diffraction shows the films to be single-phase VO2 with a monoclinic structure. The VO2 films are obtained for a narrow range of O2 injection rates which correspond to conditions where cathode poisoning is just starting to occur.

Deposition of vanadium oxide films by direct-current magnetron reactive sputtering

NASA Technical Reports Server (NTRS)

Kusano, E.; Theil, J. A.; Thornton, John A.

1988-01-01

It is demonstrated here that thin films of vanadium oxide can be deposited at modest substrate temperatures by dc reactive sputtering from a vanadium target in an O2-Ar working gas using a planar magnetron source. Resistivity ratios of about 5000 are found between a semiconductor phase with a resistivity of about 5 Ohm cm and a metallic phase with a resistivity of about 0.001 Ohm cm for films deposited onto borosilicate glass substrates at about 400 C. X-ray diffraction shows the films to be single-phase VO2 with a monoclinic structure. The VO2 films are obtained for a narrow range of O2 injection rates which correspond to conditions where cathode poisoning is just starting to occur.

Reactive Distillation and Air Stripping Processes for Water Recycling and Trace Contaminant Control

NASA Technical Reports Server (NTRS)

Boul, Peter J.; Lange, Kevin E.; Conger, Bruce; Anderson, Molly

2009-01-01

Reactive distillation designs are considered to reduce the presence of volatile organic compounds in the purified water. Reactive distillation integrates a reactor with a distillation column. A review of the literature in this field has revealed a variety of functional reactive columns in industry. Wastewater may be purified by a combination of a reactor and a distiller (e.g., the EWRS or VPCAR concepts) or, in principle, through a design which integrates the reactor with the distiller. A review of the literature in reactive distillation has identified some different designs in such combinations of reactor and distiller. An evaluation of reactive distillation and reactive air stripping is presented with regards to the reduction of volatile organic compounds in the contaminated water and air. Among the methods presented, an architecture is presented for the evaluation of the simultaneous oxidation of organics in air and water. These and other designs are presented in light of potential improvements in power consumptions and air and water purities for architectures which include catalytic activity integrated into the water processor. In particular, catalytic oxidation of organics may be useful as a tool to remove contaminants that more traditional distillation and/or air stripping columns may not remove. A review of the current leading edge at the commercial level and at the research frontier in catalytically active materials is presented. Themes and directions from the engineering developments in catalyst design are presented conceptually in light of developments in the nanoscale chemistry of a variety of catalyst materials.

Does attention redirection contribute to the effectiveness of attention bias modification on social anxiety?

PubMed

Yao, Nisha; Yu, Hongyu; Qian, Mingyi; Li, Songwei

2015-12-01

Attention bias modification (ABM) is designed to modify threat-related attention bias and thus alleviate anxiety. The current research examined whether consistently directing attention towards targeted goals per se contributes to ABM efficacy. We randomly assigned 68 non-clinical college students with elevated social anxiety to non-valence-specific attend-to-geometrics (AGC), attention modification (AMC), or attention control (ACC) conditions. We assessed subjective, behavioral, and physiological reactivity to a speech task and self-reported social anxiety symptoms. After training, participants in the AMC exhibited an attention avoidance from threat, and those in the AGC responded more rapidly toward targeted geometrics. There was a significant pre- to post-reduction in subjective speech distress across groups, but behavioral and physiological reactivity to speech, as well as self-report social anxiety symptoms, remained unchanged. These results lead to questions concerning effectiveness of ABM training for reducing social anxiety. Further examination of the current ABM protocol is required. Copyright © 2015 Elsevier Ltd. All rights reserved.

Age Differences in Affective and Cardiovascular Responses to a Negative Social Interaction: The Role of Goals, Appraisals, and Emotion Regulation

PubMed Central

Luong, Gloria; Charles, Susan T.

2014-01-01

Older adults often report less affective reactivity to interpersonal tensions than younger individuals, but few studies have directly investigated mechanisms explaining this effect. The current study examined whether older adults’ differential endorsement of goals, appraisals, and emotion regulation strategies (i.e., conflict avoidance/de-escalation, self-distraction) during a controlled negative social interaction may explain age differences in affective and cardiovascular responses to the conflict discussion. Participants (N=159; 80 younger adults, 79 older adults) discussed hypothetical dilemmas with disagreeable confederates. Throughout the laboratory session, participants’ subjective emotional experience, blood pressure, and pulse rate were assessed. Older adults generally exhibited less reactivity (negative affect reactivity, diastolic blood pressure reactivity, and pulse rate reactivity) to the task, and more pronounced positive and negative affect recovery following the task, than did younger adults. Older adults appraised the task as more enjoyable and the confederate as more likeable, and more strongly endorsed goals to perform well on the task, which mediated age differences in negative affect reactivity, pulse rate reactivity, and positive affect recovery (i.e., increases in post-task positive affect), respectively. In addition, younger adults showed increased negative affect reactivity with greater use of self-distraction, whereas older adults did not. Together, findings suggest that older adults respond less negatively to unpleasant social interactions than younger adults, and these responses are explained in part by older adults’ pursuit of different motivational goals, less threatening appraisals of the social interaction, and more effective use of self-distraction, compared to younger adults. PMID:24773101

Total OH reactivity study from VOC photochemical oxidation in the SAPHIR chamber

NASA Astrophysics Data System (ADS)

Yu, Z.; Tillmann, R.; Hohaus, T.; Fuchs, H.; Novelli, A.; Wegener, R.; Kaminski, M.; Schmitt, S. H.; Wahner, A.; Kiendler-Scharr, A.

2015-12-01

It is well known that hydroxyl radicals (OH) act as a dominant reactive species in the degradation of VOCs in the atmosphere. In recent field studies, directly measured total OH reactivity often showed poor agreement with OH reactivity calculated from VOC measurements (e.g. Nölscher et al., 2013; Lu et al., 2012a). This "missing OH reactivity" is attributed to unaccounted biogenic VOC emissions and/or oxidation products. The comparison of total OH reactivity being directly measured and calculated from single component measurements of VOCs and their oxidation products gives us a further understanding on the source of unmeasured reactive species in the atmosphere. This allows also the determination of the magnitude of the contribution of primary VOC emissions and their oxidation products to the missing OH reactivity. A series of experiments was carried out in the atmosphere simulation chamber SAPHIR in Jülich, Germany, to explore in detail the photochemical degradation of VOCs (isoprene, ß-pinene, limonene, and D6-benzene) by OH. The total OH reactivity was determined from the measurement of VOCs and their oxidation products by a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS) with a GC/MS/FID system, and directly measured by a laser-induced fluorescence (LIF) at the same time. The comparison between these two total OH reactivity measurements showed an increase of missing OH reactivity in the presence of oxidation products of VOCs, indicating a strong contribution to missing OH reactivity from uncharacterized oxidation products.

Management of Trypanosoma cruzi coinfection in HIV-positive individuals outside endemic areas.

PubMed

Pérez-Molina, José A

2014-02-01

Chagas disease has spread beyond the geographical barriers of the American continent in the past decade. Consequently, physicians treating HIV-infected patients in nonendemic countries have to face an opportunistic infection they have little experience with. This review examines the literature on Chagas disease in HIV-infected patients, with special emphasis on recent findings. Although infection by Trypanosoma cruzi is a severe opportunistic infection in HIV-infected patients, awareness of this parasitosis in nonendemic countries remains low. Deeply immunosuppressed patients with chronic infection can develop reactivations, which can be very severe and are associated with high mortality. Reactivations mostly affect the central nervous system, followed by the heart, and diagnosis is based on the direct detection of the parasite or histology. There is no reliable method of predicting reactivations. Treatment is based on benzimidazoles, although neither the appropriate treatment schedule nor the need for secondary prophylaxis has been clearly established. Antiretroviral therapy seems to play a fundamental role in the prevention of reactivations and control of relapses; however, more information is needed. Many aspects of T. cruzi-HIV coinfection remain uncertain. Until new data covering the current gaps become available, early diagnosis and prompt antiretroviral therapy seem to be fundamental for avoiding reactivations and improving late visceral involvement.

Maternal Posttraumatic Stress Symptoms and Infant Emotional Reactivity and Emotion Regulation

PubMed Central

Enlow, Michelle Bosquet; Kitts, Robert L.; Blood, Emily; Bizarro, Andrea; Hofmeister, Michelle; Wright, Rosalind J.

2011-01-01

The current study examined associations between maternal posttraumatic stress disorder (PTSD) symptoms and infant emotional reactivity and emotion regulation during the first year of life in a primarily low-income, urban, ethnic/racial minority sample of 52 mother-infant dyads. Mothers completed questionnaires assessing their own trauma exposure history and current PTSD and depressive symptoms and their infants’ temperament when the infants were 6 months old. Dyads participated in the repeated Still-Face Paradigm (SFP-R) when the infants were 6 months old, and infant affective states were coded for each SFP-R episode. Mothers completed questionnaires assessing infant trauma exposure history and infant current emotional and behavioral symptoms when the infants were 13 months old. Maternal PTSD symptoms predicted infants’ emotion regulation at 6 months as assessed by (a) infant ability to recover from distress during the SFP-R and (b) maternal report of infant rate of recovery from distress/arousal in daily life. Maternal PTSD symptoms also predicted maternal report of infant externalizing, internalizing, and dysregulation symptoms at 13 months. Maternal PTSD was not associated with measures of infant emotional reactivity. Neither maternal depressive symptoms nor infant direct exposure to trauma accounted for the associations between maternal PTSD symptoms and infant outcomes. These findings suggest that maternal PTSD is associated with offspring emotion regulation difficulties as early as infancy. Such difficulties may contribute to increased risk of mental health problems among children of mothers with PTSD. PMID:21862136

A MATLAB-based finite-element visualization of quantum reactive scattering. I. Collinear atom-diatom reactions

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

Warehime, Mick; Alexander, Millard H., E-mail: mha@umd.edu

We restate the application of the finite element method to collinear triatomic reactive scattering dynamics with a novel treatment of the scattering boundary conditions. The method provides directly the reactive scattering wave function and, subsequently, the probability current density field. Visualizing these quantities provides additional insight into the quantum dynamics of simple chemical reactions beyond simplistic one-dimensional models. Application is made here to a symmetric reaction (H+H{sub 2}), a heavy-light-light reaction (F+H{sub 2}), and a heavy-light-heavy reaction (F+HCl). To accompany this article, we have written a MATLAB code which is fast, simple enough to be accessible to a wide audience,more » as well as generally applicable to any problem that can be mapped onto a collinear atom-diatom reaction. The code and user's manual are available for download from http://www2.chem.umd.edu/groups/alexander/FEM.« less

Clarifying Relations Between Dispositional Aggression and Brain Potential Response: Overlapping and Distinct Contributions of Impulsivity and Stress Reactivity

PubMed Central

Venables, Noah C.; Patrick, Christopher J.; Hall, Jason R.; Bernat, Edward M.

2011-01-01

Impulsive-aggressive individuals exhibit deficits in amplitude of the P3 brain potential response, however, it remains unclear how separable dispositional traits account for this association. The current study sought to clarify the basis of this association by examining contributions of trait impulsiveness and stress reactivity to the observed relationship between dispositional aggression and amplitude of the P3 brain potential response in a visual novelty-oddball procedure. A significant negative association was found between aggressiveness and amplitude of P3 response to both target and novel stimuli over frontal-central scalp sites. Impulsivity showed a parallel inverse relationship with P3 amplitude, attributable to its overlap with dispositional aggression. In contrast, stress reactivity did not exhibit a zero-order association with P3 amplitude, but modestly predicted P3 in a positive direction after accounting for its overlap with aggression. Results are discussed in terms of their implications for individual difference variables and brain processes underlying impulsive-aggressive behavior. PMID:21262318

Impact of Adverse Childhood Experiences on Psychotic-Like Symptoms and Stress Reactivity in Daily Life in Nonclinical Young Adults

PubMed Central

Ballespí, Sergi; Mitjavila, Mercè; Myin-Germeys, Inez; Kwapil, Thomas R.; Barrantes-Vidal, Neus

2016-01-01

Background There is increasing interest in elucidating the association of different childhood adversities with psychosis-spectrum symptoms as well as the mechanistic processes involved. This study used experience sampling methodology to examine (i) associations of a range of childhood adversities with psychosis symptom domains in daily life; (ii) whether associations of abuse and neglect with symptoms are consistent across self-report and interview methods of trauma assessment; and (iii) the role of different adversities in moderating affective, psychotic-like, and paranoid reactivity to situational and social stressors. Method A total of 206 nonclinical young adults were administered self-report and interview measures to assess childhood abuse, neglect, bullying, losses, and general traumatic events. Participants received personal digital assistants that signaled them randomly eight times daily for one week to complete questionnaires about current experiences, including symptoms, affect, and stress. Results Self-reported and interview-based abuse and neglect were associated with psychotic-like and paranoid symptoms, whereas only self-reported neglect was associated with negative-like symptoms. Bullying was associated with psychotic-like symptoms. Losses and general traumatic events were not directly associated with any of the symptom domains. All the childhood adversities were associated with stress reactivity in daily life. Interpersonal adversities (abuse, neglect, bullying, and losses) moderated psychotic-like and/or paranoid reactivity to situational and social stressors, whereas general traumatic events moderated psychotic-like reactivity to situational stress. Also, different interpersonal adversities exacerbated psychotic-like and/or paranoid symptoms in response to distinct social stressors. Discussion The present study provides a unique examination of how childhood adversities impact the expression of spectrum symptoms in the real world and lends support to the notion that stress reactivity is a mechanism implicated in the experience of reality distortion in individuals exposed to childhood trauma. Investigating the interplay between childhood experience and current context is relevant for uncovering potential pathways to the extended psychosis phenotype. PMID:27082442

Blood Stage Plasmodium falciparum Exhibits Biological Responses to Direct Current Electric Fields

PubMed Central

Coronado, Lorena M.; Montealegre, Stephania; Chaverra, Zumara; Mojica, Luis; Espinosa, Carlos; Almanza, Alejandro; Correa, Ricardo; Stoute, José A.; Gittens, Rolando A.

2016-01-01

The development of resistance to insecticides by the vector of malaria and the increasingly faster appearance of resistance to antimalarial drugs by the parasite can dangerously hamper efforts to control and eradicate the disease. Alternative ways to treat this disease are urgently needed. Here we evaluate the in vitro effect of direct current (DC) capacitive coupling electrical stimulation on the biology and viability of Plasmodium falciparum. We designed a system that exposes infected erythrocytes to different capacitively coupled electric fields in order to evaluate their effect on P. falciparum. The effect on growth of the parasite, replication of DNA, mitochondrial membrane potential and level of reactive oxygen species after exposure to electric fields demonstrate that the parasite is biologically able to respond to stimuli from DC electric fields involving calcium signaling pathways. PMID:27537497

Blood Stage Plasmodium falciparum Exhibits Biological Responses to Direct Current Electric Fields.

PubMed

Coronado, Lorena M; Montealegre, Stephania; Chaverra, Zumara; Mojica, Luis; Espinosa, Carlos; Almanza, Alejandro; Correa, Ricardo; Stoute, José A; Gittens, Rolando A; Spadafora, Carmenza

2016-01-01

The development of resistance to insecticides by the vector of malaria and the increasingly faster appearance of resistance to antimalarial drugs by the parasite can dangerously hamper efforts to control and eradicate the disease. Alternative ways to treat this disease are urgently needed. Here we evaluate the in vitro effect of direct current (DC) capacitive coupling electrical stimulation on the biology and viability of Plasmodium falciparum. We designed a system that exposes infected erythrocytes to different capacitively coupled electric fields in order to evaluate their effect on P. falciparum. The effect on growth of the parasite, replication of DNA, mitochondrial membrane potential and level of reactive oxygen species after exposure to electric fields demonstrate that the parasite is biologically able to respond to stimuli from DC electric fields involving calcium signaling pathways.

Longitudinal Relations between Beliefs Supporting Aggression,Anger Regulation, and Dating Aggression among Early Adolescents.

PubMed

Sullivan, Terri N; Garthe, Rachel C; Goncy, Elizabeth A; Carlson, Megan M; Behrhorst, Kathryn L

2017-05-01

Dating aggression occurs frequently in early to mid-adolescence and has negative repercussions for psychosocial adjustment and physical health. The patterns of behavior learned during this developmental timeframe may persist in future dating relationships, underscoring the need to identify risk factors for this outcome. The current study examined longitudinal relations between beliefs supporting aggression, anger regulation, and dating aggression. Participants were 176 middle school students in sixth, seventh, and eighth grade (50 % female; 82 % African American). No direct effects were found between beliefs supporting reactive or proactive aggression and dating aggression. Beliefs supporting reactive aggression predicted increased rates of anger dysregulation, and beliefs supporting proactive aggression led to subsequent increases in anger inhibition. Anger dysregulation and inhibition were associated with higher frequencies of dating aggression. An indirect effect was found for the relation between beliefs supporting reactive aggression and dating aggression via anger dysregulation. Another indirect effect emerged for the relation between beliefs supporting proactive aggression and dating aggression through anger inhibition. The study's findings suggested that beliefs supporting proactive and reactive aggression were differentially related to emotion regulation processes, and identified anger dysregulation and inhibition as risk factors for dating aggression among adolescents.

Intercomparison of two comparative reactivity method instruments inf the Mediterranean basin during summer 2013

NASA Astrophysics Data System (ADS)

Zannoni, N.; Dusanter, S.; Gros, V.; Sarda Esteve, R.; Michoud, V.; Sinha, V.; Locoge, N.; Bonsang, B.

2015-09-01

The hydroxyl radical (OH) plays a key role in the atmosphere, as it initiates most of the oxidation processes of volatile organic compounds (VOCs), and can ultimately lead to the formation of ozone and secondary organic aerosols (SOAs). There are still uncertainties associated with the OH budget assessed using current models of atmospheric chemistry and direct measurements of OH sources and sinks have proved to be valuable tools to improve our understanding of the OH chemistry. The total first order loss rate of OH, or total OH reactivity, can be directly measured using three different methods, such as the following: total OH loss rate measurement, laser-induced pump and probe technique and comparative reactivity method. Observations of total OH reactivity are usually coupled to individual measurements of reactive compounds in the gas phase, which are used to calculate the OH reactivity. Studies using the three methods have highlighted that a significant fraction of OH reactivity is often not explained by individually measured reactive compounds and could be associated to unmeasured or unknown chemical species. Therefore accurate and reproducible measurements of OH reactivity are required. The comparative reactivity method (CRM) has demonstrated to be an advantageous technique with an extensive range of applications, and for this reason it has been adopted by several research groups since its development. However, this method also requires careful corrections to derive ambient OH reactivity. Herein we present an intercomparison exercise of two CRM instruments, CRM-LSCE (Laboratoire des Sciences du Climat et de l'Environnement) and CRM-MD (Mines Douai), conducted during July 2013 at the Mediterranean site of Ersa, Cape Corsica, France. The intercomparison exercise included tests to assess the corrections needed by the two instruments to process the raw data sets as well as OH reactivity observations. The observation was divided in three parts: 2 days of plant emissions (8-9 July), 2 days of ambient measurements (10-11 July) and 2 days (12-13 July) of plant emissions. We discuss in detail the experimental approach adopted and how the data sets were processed for both instruments. Corrections required for the two instruments lead to higher values of reactivity in ambient air; overall 20 % increase for CRM-MD and 49 % for CRM-LSCE compared to the raw data. We show that ambient OH reactivity measured by the two instruments agrees very well (correlation described by a linear least squares fit with a slope of 1 and R2 of 0.75). This study highlights that ambient measurements of OH reactivity with differently configured CRM instruments yield consistent results in a low NOx (NO + NO2), terpene rich environment, despite differential corrections relevant to each instrument. Conducting more intercomparison exercises, involving more CRM instruments operated under different ambient and instrumental settings will help in assessing the variability induced due to instrument-specific corrections further.

A large OH sink in summertime surface air of the northern Indo-Gangetic plain revealed through in-situ total OH Reactivity measurements

NASA Astrophysics Data System (ADS)

Kumar, V.; Garg, S.; Chandra, P.; Sinha, V.

2013-12-01

The summertime surface air in the Northern Indo-Gangetic plain is characterized by high temperatures (up to 47 oC) and strong solar radiation (up to 765 Watt/m2), which together with large urban and agricultural emissions in the densely populated region, lead to intense photochemistry. The hydroxyl radical (OH) is the primary atmospheric oxidant responsible for oxidizing gaseous emissions and hence direct measurements of the total OH reactivity are necessary for understanding reactive emission budgets and constraining instantaneous ozone production regimes. Here, we present the first dataset of direct OH reactivity measurements from a regional surface site in the northern India-Gangetic plain (30.667°N, 76.729°E; 310 m above mean sea level). The measurements were performed in April-May 2013 using the comparative reactivity method [1]. A single PTRMS was used for sequential measurements of the total OH reactivity and circa 20 ambient VOCs. Nitrogen oxides (NO and NO2), sulphur dioxide, carbon monoxide, ozone and meteorological parameters were measured concomitantly using the IISER Mohali atmospheric chemistry facility. Air masses impacting the site arrived from rural and agricultural regions at high wind speeds of up to 24 m/s. A large variability was observed in the diel hourly averaged OH reactivity spanning an interquartile range of 36 s-1 - 120 s-1. The daily average and median total OH reactivity was 76 s-1 and 73 s-1, respectively corresponding to average and median OH chemical lifetimes of 13.1 milliseconds and 13.6 milliseconds, respectively. The five highest individual OH sinks measured were: acetaldehyde > isoprene+furan > NO2 > trimethyl benzene > CO. The measured OH reactivity did not show a pronounced diel cycle but remarkably the highest missing OH reactivity fraction (> 50 %) was observed during afternoon hours (12-16 local time) on very sunny days with low RH. This suggests that a significant fraction of secondary oxidation products formed due to photochemical oxidation reactions remain unmeasured. Likely compounds that could help explain the missing OH reactivity but were not covered by the measurement suite during the study period will be discussed in the presentation. Employing the ratio of the measured OH reactivity due to VOCs and due to NOx respectively [2], the peak ozone production at the site currently appears to be limited by the availability of NOx. References 1. V. Sinha et al., The Comparative Reactivity Method - a new tool to measure total OH Reactivity in ambient air. Atmos. Chem. Phys, 2008: p. 2213-2227. 2. V. Sinha,et al., Constraints on instantaneous ozone production rates and regimes during DOMINO derived using in-situ OH reactivity measurements, Atmos. Chem. Phys., 12, 7269-7283, doi:10.5194/acp-12-7269-2012, 2012. Acknowledgements: We acknowledge financial support from MHRD, India, and IISER Mohali-MPI-DST partner group and thank Chinmoy Sarkar.

Attentional bias mediates the effect of neurostimulation on emotional vulnerability.

PubMed

Chen, Nigel T M; Basanovic, Julian; Notebaert, Lies; MacLeod, Colin; Clarke, Patrick J F

2017-10-01

Transcranial direct current stimulation (tDCS) is a neuromodulatory technique which has garnered recent interest in the potential treatment for emotion-based psychopathology. While accumulating evidence suggests that tDCS may attenuate emotional vulnerability, critically, little is known about underlying mechanisms of this effect. The present study sought to clarify this by examining the possibility that tDCS may affect emotional vulnerability via its capacity to modulate attentional bias towards threatening information. Fifty healthy participants were randomly assigned to receive either anodal tDCS (2 mA/min) stimulation to the left dorsolateral prefrontal cortex (DLPFC), or sham. Participants were then eye tracked during a dual-video stressor task designed to elicit emotional reactivity, while providing a concurrent in-vivo measure of attentional bias. Greater attentional bias towards threatening information was associated with greater emotional reactivity to the stressor task. Furthermore, the active tDCS group showed reduced attentional bias to threat, compared to the sham group. Importantly, attentional bias was found to statistically mediate the effect of tDCS on emotional reactivity, while no direct effect of tDCS on emotional reactivity was observed. The findings are consistent with the notion that the effect of tDCS on emotional vulnerability may be mediated by changes in attentional bias, holding implications for the application of tDCS in emotion-based psychopathology. The findings also highlight the utility of in-vivo eye tracking measures in the examination of the mechanisms associated with DLPFC neuromodulation in emotional vulnerability. Copyright © 2017 Elsevier Ltd. All rights reserved.

Can direct conversion of used nitrogen to new feed and protein help feed the world?

PubMed

Matassa, Silvio; Batstone, Damien J; Hülsen, Tim; Schnoor, Jerald; Verstraete, Willy

2015-05-05

The increase in the world population, vulnerability of conventional crop production to climate change, and population shifts to megacities justify a re-examination of current methods of converting reactive nitrogen to dinitrogen gas in sewage and waste treatment plants. Indeed, by up-grading treatment plants to factories in which the incoming materials are first deconstructed to units such as ammonia, carbon dioxide and clean minerals, one can implement a highly intensive and efficient microbial resynthesis process in which the used nitrogen is harvested as microbial protein (at efficiencies close to 100%). This can be used for animal feed and food purposes. The technology for recovery of reactive nitrogen as microbial protein is available but a change of mindset needs to be achieved to make such recovery acceptable.

Quantifying Sources and Sinks of Reactive Gases in the Lower Atmosphere Using Airborne Flux Observations

NASA Technical Reports Server (NTRS)

Wolfe, G. M.; Hanisco, T. F.; Arkinson, H. L.; Bui, T. P.; Crounse, J. D.; Dean-Day, J.; Goldstein, A.; Guenther, A.; Hall, S. R.; Huey, G.;

Hemagglutinin Stalk- and Neuraminidase-Specific Monoclonal Antibodies Protect against Lethal H10N8 Influenza Virus Infection in Mice.

PubMed

Wohlbold, Teddy John; Chromikova, Veronika; Tan, Gene S; Meade, Philip; Amanat, Fatima; Comella, Phillip; Hirsh, Ariana; Krammer, Florian

2016-01-15

Between November 2013 and February 2014, China reported three human cases of H10N8 influenza virus infection in the Jiangxi province, two of which were fatal. Using hybridoma technology, we isolated a panel of H10- and N8-directed monoclonal antibodies (MAbs) and further characterized the binding reactivity of these antibodies (via enzyme-linked immunosorbent assay) to a range of purified virus and recombinant protein substrates. The H10-directed MAbs displayed functional hemagglutination inhibition (HI) and neutralization activity, and the N8-directed antibodies displayed functional neuraminidase inhibition (NI) activity against H10N8. Surprisingly, the HI-reactive H10 antibodies, as well as a previously generated, group 2 hemagglutinin (HA) stalk-reactive antibody, demonstrated NI activity against H10N8 and an H10N7 strain; this phenomenon was absent when virus was treated with detergent, suggesting the anti-HA antibodies inhibited neuraminidase enzymatic activity through steric hindrance. We tested the prophylactic efficacy of one representative H10-reactive, N8-reactive, and group 2 HA stalk-reactive antibody in vivo using a BALB/c challenge model. All three antibodies were protective at a high dose (5 mg/kg). At a low dose (0.5 mg/kg), only the anti-N8 antibody prevented weight loss. Together, these data suggest that antibody targets other than the globular head domain of the HA may be efficacious in preventing influenza virus-induced morbidity and mortality. Avian H10N8 and H10N7 viruses have recently crossed the species barrier, causing morbidity and mortality in humans and other mammals. Although these reports are likely isolated incidents, it is possible that more cases may emerge in future winter seasons, similar to H7N9. Furthermore, regular transmission of avian influenza viruses to humans increases the risk of adaptive mutations and reassortment events, which may result in a novel virus with pandemic potential. Currently, no specific therapeutics or vaccines are available against the H10N8 influenza virus subtype. We generated a panel of H10- and N8-reactive MAbs. Although these antibodies may practically be developed into therapeutic agents, characterizing the protective potential of MAbs that have targets other than the HA globular head domain will provide insight into novel antibody-mediated mechanisms of protection and help to better understand correlates of protection for influenza A virus infection. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Atmospheric-pressure cold plasma treatment of contaminated fresh fruit and vegetable slices: inactivation and physiochemical properties evaluation

NASA Astrophysics Data System (ADS)

Wang, R. X.; Nian, W. F.; Wu, H. Y.; Feng, H. Q.; Zhang, K.; Zhang, J.; Zhu, W. D.; Becker, K. H.; Fang, J.

2012-10-01

A direct-current, atmospheric-pressure air cold plasma microjet (PMJ) was applied to disinfect Salmonella directly deposited on fresh fruit and vegetable slices. Effective inactivation was achieved on sliced fruit and vegetables after 1 s plasma treatment. The physiochemical properties of the slices, such as water content, color parameters, and nutritional content were monitored before and after plasma treatment. It was found that the physiochemical properties changes caused by the plasma were within an acceptable range. Reactive oxygen species, which are believed to be the major bactericidal agents in the plasma, were detected by electron spin resonance spectroscopy and optical emission spectroscopy.

Initial Comparison of Direct and Legacy Modeling Approaches for Radial Core Expansion Analysis

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

Shemon, Emily R.

2016-10-10

Radial core expansion in sodium-cooled fast reactors provides an important reactivity feedback effect. As the reactor power increases due to normal start up conditions or accident scenarios, the core and surrounding materials heat up, causing both grid plate expansion and bowing of the assembly ducts. When the core restraint system is designed correctly, the resulting structural deformations introduce negative reactivity which decreases the reactor power. Historically, an indirect procedure has been used to estimate the reactivity feedback due to structural deformation which relies upon perturbation theory and coupling legacy physics codes with limited geometry capabilities. With advancements in modeling andmore » simulation, radial core expansion phenomena can now be modeled directly, providing an assessment of the accuracy of the reactivity feedback coefficients generated by indirect legacy methods. Recently a new capability was added to the PROTEUS-SN unstructured geometry neutron transport solver to analyze deformed meshes quickly and directly. By supplying the deformed mesh in addition to the base configuration input files, PROTEUS-SN automatically processes material adjustments including calculation of region densities to conserve mass, calculation of isotopic densities according to material models (for example, sodium density as a function of temperature), and subsequent re-homogenization of materials. To verify the new capability of directly simulating deformed meshes, PROTEUS-SN was used to compute reactivity feedback for a series of contrived yet representative deformed configurations for the Advanced Burner Test Reactor design. The indirect legacy procedure was also performed to generate reactivity feedback coefficients for the same deformed configurations. Interestingly, the legacy procedure consistently overestimated reactivity feedbacks by 35% compared to direct simulations by PROTEUS-SN. This overestimation indicates that the legacy procedures are in fact not conservative and could be overestimating reactivity feedback effects that are closely tied to reactor safety. We conclude that there is indeed value in performing direct simulation of deformed meshes despite the increased computational expense. PROTEUS-SN is already part of the SHARP multi-physics toolkit where both thermal hydraulics and structural mechanical feedback modeling can be applied but this is the first comparison of direct simulation to legacy techniques for radial core expansion.« less

Deposition and characterization of TiAlSiN nanocomposite coatings prepared by reactive pulsed direct current unbalanced magnetron sputtering

NASA Astrophysics Data System (ADS)

Barshilia, Harish C.; Ghosh, Moumita; Shashidhara; Ramakrishna, Raja; Rajam, K. S.

2010-08-01

This work reports the performance of high speed steel drill bits coated with TiAlSiN nanocomposite coating at different Si contents (5.5-8.1 at.%) prepared using a four-cathode reactive pulsed direct current unbalanced magnetron sputtering system. The surface morphology of the as-deposited coatings was characterized using field emission scanning electron microscopy. The crystallographic structure, chemical composition and bonding structure were evaluated using X-ray diffraction, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, respectively. The corrosion behavior, mechanical properties and thermal stability of TiAlSiN nanocomposite coatings were also studied using potentiodynamic polarization, nanoindentation and Raman spectroscopy, respectively. The TiAlSiN coating thickness was approximately 2.5-2.9 μm. These coatings exhibited a maximum hardness of 38 GPa at a silicon content of approximately 6.9 at.% and were stable in air up to 850 °C. For the performance evaluation, the TiAlSiN coated drills were tested under accelerated machining conditions by drilling a 12 mm thick 304 stainless steel plate. Under dry conditions the uncoated drill bits failed after drilling 50 holes, whereas, TiAlSiN coated drill bits (Si = 5.5 at.%) drilled 714 holes before failure. Results indicated that for TiAlSiN coated drill bits the tool life increased by a factor of more than 14.

Reaction-space analysis of homogeneous charge compression ignition combustion with varying levels of fuel stratification under positive and negative valve overlap conditions

DOE PAGES

Kodavasal, Janardhan; Lavoie, George A.; Assanis, Dennis N.; ...

2015-10-26

Full-cycle computational fluid dynamics simulations with gasoline chemical kinetics were performed to determine the impact of breathing and fuel injection strategies on thermal and compositional stratification, combustion and emissions during homogeneous charge compression ignition combustion. The simulations examined positive valve overlap and negative valve overlap strategies, along with fueling by port fuel injection and direct injection. The resulting charge mass distributions were analyzed prior to ignition using ignition delay as a reactivity metric. The reactivity stratification arising from differences in the distributions of fuel–oxygen equivalence ratio (Φ FO), oxygen molar fraction (χ O2) and temperature (T) was determined for threemore » parametric studies. In the first study, the reactivity stratification and burn duration for positive valve overlap valve events with port fuel injection and early direct injection were nearly identical and were dominated by wall-driven thermal stratification. nitrogen oxide (NO) and carbon monoxide (CO) emissions were negligible for both injection strategies. In the second study, which examined negative valve overlap valve events with direct injection and port fuel injection, reactivity stratification increased for direct injection as the Φ FO and T distributions associated with direct fuel injection into the hot residual gas were positively correlated; however, the latent heat absorbed from the hot residual gas by the evaporating direct injection fuel jet reduced the overall thermal and reactivity stratification. These stratification effects were offsetting, resulting in similar reactivity stratification and burn durations for the two injection strategies. The higher local burned gas temperatures with direct injection resulted in an order of magnitude increase in NO, while incomplete combustion of locally over-lean regions led to a sevenfold increase in CO emissions compared to port fuel injection. The final study evaluated positive valve overlap and negative valve overlap valve events with direct injection. Furthermore, relative to positive valve overlap, the negative valve overlap condition had a wider reactivity stratification, a longer burn duration and higher NO and CO emissions associated with reduced fuel–air mixing.« less

Mood Reactivity Rather than Cognitive Reactivity Is Predictive of Depressive Relapse: A Randomized Study with 5.5-Year Follow-Up

ERIC Educational Resources Information Center

van Rijsbergen, Gerard D.; Bockting, Claudi L. H.; Burger, Huibert; Spinhoven, Philip; Koeter, Maarten W. J.; Ruhe, Henricus G.; Hollon, Steven D.; Schene, Aart H.

2013-01-01

Objective: The current study examined whether cognitive reactivity, cognitive extremity reactivity, and mood reactivity following mood provocation predicted relapse in depression over 5.5 years. Additionally, this study was the 1st to examine whether changes in cognitive reactivity and mood reactivity following preventive cognitive therapy (PCT)…

Controls on Early-Rift Geometry: New Perspectives From the Bilila-Mtakataka Fault, Malawi

NASA Astrophysics Data System (ADS)

Hodge, M.; Fagereng, Å.; Biggs, J.; Mdala, H.

2018-05-01

We use the ˜110-km long Bilila-Mtakataka fault in the amagmatic southern East African Rift, Malawi, to investigate the controls on early-rift geometry at the scale of a major border fault. Morphological variations along the 14 ± 8-m high scarp define six 10- to 40-km long segments, which are either foliation parallel or oblique to both foliation and the current regional extension direction. As the scarp is neither consistently parallel to foliation nor well oriented for the current regional extension direction, we suggest that the segmented surface expression is related to the local reactivation of well-oriented weak shallow fabrics above a broadly continuous structure at depth. Using a geometrical model, the geometry of the best fitting subsurface structure is consistent with the local strain field from recent seismicity. In conclusion, within this early-rift, preexisting weaknesses only locally control border fault geometry at subsurface.

Reactivity and oxygen diffusion property of resistive barriers for Bi-2223/Ag tapes

NASA Astrophysics Data System (ADS)

Kováč, P.; Hušek, I.

2002-12-01

Reactivity of several oxide materials (OM) with BSCCO powder and oxygen diffusion through OM layer has been tested at temperature ≈840 °C in air. The OM (e.g.: BaZrO 3, SrCO 3, MgO and ZrO 2) showing the low or no reactivity with BSCCO have been mixed (10 wt.%) with precursor powder and used for single-core tapes. Bi-2223/Ag/OM/Ag single-core tapes with oxide barriers made of BaZrO 3, SrCO 3, ZrO 2 and Al 2O 3 have been also prepared by a standard powder-in-tube technique. The used OM in the direct contact with BSCCO influences the electrical properties of Bi-2223 phase differently. These is because the oxides react with BSCCO during the heat treatment and simultaneously affect the 2212→2223 phase transformation, the Bi-2223 grain growth and so also grain connectivity. SrCO 3 powder has been evaluated as the best material from the point of no destructive effect on 2223 phase transport current property. The oxide barrier controls the oxygen diffusion during the tape heat treatment and simultaneously the HTS phase formation kinetics, its purity and content within the superconducting core. For single-core Bi-2223/Ag/OM/Ag tapes, the highest current density was measured for Al 2O 3 due to only slightly reduced oxygen diffusion through the barrier.

Optimal Transmission Line Switching under Geomagnetic Disturbances

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

Lu, Mowen; Nagarajan, Harsha; Yamangil, Emre

Recently, there have been increasing concerns about how geomagnetic disturbances (GMDs) impact electrical power systems. Geomagnetically-induced currents (GICs) can saturate transformers, induce hot spot heating and increase reactive power losses. These effects can potentially cause catastrophic damage to transformers and severely impact the ability of a power system to deliver power. To address this problem, we develop a model of GIC impacts to power systems that includes 1) GIC thermal capacity of transformers as a function of normal Alternating Current (AC) and 2) reactive power losses as a function of GIC. We also use this model to derive an optimizationmore » problem that protects power systems from GIC impacts through line switching, generator dispatch, and load shedding. We then employ state-of-the-art convex relaxations of AC power flow equations to lower bound the objective. We demonstrate the approach on a modified RTS96 system and UIUC 150-bus system and show that line switching is an effective means to mitigate GIC impacts. We also provide a sensitivity analysis of decisions with respect to GMD direction.« less

Optimal Transmission Line Switching under Geomagnetic Disturbances

DOE PAGES

Lu, Mowen; Nagarajan, Harsha; Yamangil, Emre; ...

2017-10-11

Recently, there have been increasing concerns about how geomagnetic disturbances (GMDs) impact electrical power systems. Geomagnetically-induced currents (GICs) can saturate transformers, induce hot spot heating and increase reactive power losses. These effects can potentially cause catastrophic damage to transformers and severely impact the ability of a power system to deliver power. To address this problem, we develop a model of GIC impacts to power systems that includes 1) GIC thermal capacity of transformers as a function of normal Alternating Current (AC) and 2) reactive power losses as a function of GIC. We also use this model to derive an optimizationmore » problem that protects power systems from GIC impacts through line switching, generator dispatch, and load shedding. We then employ state-of-the-art convex relaxations of AC power flow equations to lower bound the objective. We demonstrate the approach on a modified RTS96 system and UIUC 150-bus system and show that line switching is an effective means to mitigate GIC impacts. We also provide a sensitivity analysis of decisions with respect to GMD direction.« less

Trends in reactivity of electrodeposited 3d transition metals on gold revealed by operando soft x-ray absorption spectroscopy during water splitting

NASA Astrophysics Data System (ADS)

Velasco-Vélez, J. J.; Jones, Travis E.; Pfeifer, Verena; Dong, Chung-Li; Chen, Yu-Xun; Chen, Chieh-Ming; Chen, Hsin-Yu; Lu, Ying-Rui; Chen, Jin-Ming; Schlögl, R.; Knop-Gericke, A.; Chuang, C.-H.

2017-01-01

We activated gold electrodes for their use as electrocatalyst for water splitting by electrodepositing Cu, Ni and Co. A combination of operando x-ray absorption spectroscopy and potentiometric control under aqueous conditions revealed the trends in reactivity yielded by these electrodes, which are directly associated with the cross- and overpotentials as well as the occupancy of the 3d orbitals. It was found that under anodic polarization the materials electrodeposited on gold suffer from a lack of stability, while under cathodic polarization they exhibit stable behavior. The observed activity is strongly related to the lack of stability shown by these composites under anodic polarization revealing a dynamic process ruled by corrosion. By operando x-ray absorption, we established that the overall enhancement of the activity for the oxygen evolution reaction is directly attributable to the cross-potential and corrosion process of the electrodeposited materials. It is associated with the high potential deposition, which is the origin of the incipient oxidation-corrosion resistance of the lattice. We conclude that the observed trends in the total current are directly associated with the loss of oxygen in the metal-oxide lattice and the subsequent dissolution of metallic ions in the electrolyte under anodic polarization.

Comparison of OH reactivity measurements in the atmospheric simulation chamber SAPHIR

NASA Astrophysics Data System (ADS)

Fuchs, Hendrik; Novelli, Anna; Rolletter, Michael; Hofzumahaus, Andreas; Pfannerstill, Eva Y.; Kessel, Stephan; Edtbauer, Achim; Williams, Jonathan; Michoud, Vincent; Dusanter, Sebastien; Locoge, Nadine; Zannoni, Nora; Gros, Valerie; Truong, Francois; Sarda-Esteve, Roland; Cryer, Danny R.; Brumby, Charlotte A.; Whalley, Lisa K.; Stone, Daniel; Seakins, Paul W.; Heard, Dwayne E.; Schoemaecker, Coralie; Blocquet, Marion; Coudert, Sebastien; Batut, Sebastien; Fittschen, Christa; Thames, Alexander B.; Brune, William H.; Ernest, Cheryl; Harder, Hartwig; Muller, Jennifer B. A.; Elste, Thomas; Kubistin, Dagmar; Andres, Stefanie; Bohn, Birger; Hohaus, Thorsten; Holland, Frank; Li, Xin; Rohrer, Franz; Kiendler-Scharr, Astrid; Tillmann, Ralf; Wegener, Robert; Yu, Zhujun; Zou, Qi; Wahner, Andreas

2017-10-01

Hydroxyl (OH) radical reactivity (kOH) has been measured for 18 years with different measurement techniques. In order to compare the performances of instruments deployed in the field, two campaigns were conducted performing experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich in October 2015 and April 2016. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. All types of instruments that are currently used for atmospheric measurements were used in one of the two campaigns. The results of these campaigns demonstrate that OH reactivity can be accurately measured for a wide range of atmospherically relevant chemical conditions (e.g. water vapour, nitrogen oxides, various organic compounds) by all instruments. The precision of the measurements (limit of detection < 1 s-1 at a time resolution of 30 s to a few minutes) is higher for instruments directly detecting hydroxyl radicals, whereas the indirect comparative reactivity method (CRM) has a higher limit of detection of 2 s-1 at a time resolution of 10 to 15 min. The performances of the instruments were systematically tested by stepwise increasing, for example, the concentrations of carbon monoxide (CO), water vapour or nitric oxide (NO). In further experiments, mixtures of organic reactants were injected into the chamber to simulate urban and forested environments. Overall, the results show that the instruments are capable of measuring OH reactivity in the presence of CO, alkanes, alkenes and aromatic compounds. The transmission efficiency in Teflon inlet lines could have introduced systematic errors in measurements for low-volatile organic compounds in some instruments. CRM instruments exhibited a larger scatter in the data compared to the other instruments. The largest differences to reference measurements or to calculated reactivity were observed by CRM instruments in the presence of terpenes and oxygenated organic compounds (mixing ratio of OH reactants were up to 10 ppbv). In some of these experiments, only a small fraction of the reactivity is detected. The accuracy of CRM measurements is most likely limited by the corrections that need to be applied to account for known effects of, for example, deviations from pseudo first-order conditions, nitrogen oxides or water vapour on the measurement. Methods used to derive these corrections vary among the different CRM instruments. Measurements taken with a flow-tube instrument combined with the direct detection of OH by chemical ionisation mass spectrometry (CIMS) show limitations in cases of high reactivity and high NO concentrations but were accurate for low reactivity (< 15 s-1) and low NO (< 5 ppbv) conditions.

Sensors and Micromachined Devices for the Automotive and New Markets: The Delphi Delco Electronics MEMS Story.

NASA Astrophysics Data System (ADS)

Logsdon, James

2002-03-01

This presentation will provide a brief history of the development of MEMS products and technology, beginning with the manifold absolute pressure sensor in the late seventies through the current variety of Delphi Delco Electronics sensors available today. The technology development of micromachining from uncompensated P plus etch stops to deep reactive ion etching and the technology development of wafer level packaging from electrostatic bonding to glass frit sealing and silicon to silicon direct bonding will be reviewed.

Apollo experience report: Detection and minimization of ignition hazards from water/glycol contamination of silver-clad electrical circuitry

NASA Technical Reports Server (NTRS)

Downs, W. R.

1976-01-01

The potential flammability hazard when a water/glycol solution contacts defectively insulated silver-clad copper circuitry or electrical components carrying a direct current is described. The chemical reactions and means for detecting them are explained. Methods for detecting and cleaning contaminated areas and the use of inhibitors to arrest chemical reactivity are also explained. Preventive measures to minimize hazards are given. Photomicrographs of the chemical reactions occurring on silver clad wires are also included.

Quantifying sources and sinks of reactive gases in the lower atmosphere using airborne flux observations

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

Wolfe, Glenn; Hanisco, T. F.; Atkinson, H. L.

Atmospheric composition is governed by the interplay of emissions, chemistry, deposition, and transport. Substantial questions surround each of these processes, especially in forested environments with strong biogenic emissions. Utilizing aircraft observations acquired over a forest in the southeast U.S., we calculate eddy covariance fluxes for a suite of reactive gases and apply the synergistic information derived from this analysis to quantify emission and deposition fluxes, oxidant concentrations, aerosol uptake coefficients, and other key parameters. Evaluation of results against state-of-the-science models and parameterizations provides insight into our current understanding of this system and frames future observational priorities. As a near-direct measurementmore » of fundamental process rates, airborne fluxes offer a new tool to improve biogenic and anthropogenic emissions inventories, photochemical mechanisms, and deposition parameterizations.« less

Measuring and monitoring KIPT Neutron Source Facility Reactivity

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

Cao, Yan; Gohar, Yousry; Zhong, Zhaopeng

2015-08-01

Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on developing and constructing a neutron source facility at Kharkov, Ukraine. The facility consists of an accelerator-driven subcritical system. The accelerator has a 100 kW electron beam using 100 MeV electrons. The subcritical assembly has k eff less than 0.98. To ensure the safe operation of this neutron source facility, the reactivity of the subcritical core has to be accurately determined and continuously monitored. A technique which combines the area-ratio method and the flux-to-current ratio method is purposed to determine themore » reactivity of the KIPT subcritical assembly at various conditions. In particular, the area-ratio method can determine the absolute reactivity of the subcritical assembly in units of dollars by performing pulsed-neutron experiments. It provides reference reactivities for the flux-to-current ratio method to track and monitor the reactivity deviations from the reference state while the facility is at other operation modes. Monte Carlo simulations are performed to simulate both methods using the numerical model of the KIPT subcritical assembly. It is found that the reactivities obtained from both the area-ratio method and the flux-to-current ratio method are spatially dependent on the neutron detector locations and types. Numerical simulations also suggest optimal neutron detector locations to minimize the spatial effects in the flux-to-current ratio method. The spatial correction factors are calculated using Monte Carlo methods for both measuring methods at the selected neutron detector locations. Monte Carlo simulations are also performed to verify the accuracy of the flux-to-current ratio method in monitoring the reactivity swing during a fuel burnup cycle.« less

The Reactive Species Interactome: Evolutionary Emergence, Biological Significance, and Opportunities for Redox Metabolomics and Personalized Medicine

PubMed Central

Koning, Anne; Kuhnle, Gunter G.C.; Nagy, Peter; Bianco, Christopher L.; Pasch, Andreas; Wink, David A.; Fukuto, Jon M.; Jackson, Alan A.; van Goor, Harry; Olson, Kenneth R.

2017-01-01

Abstract Significance: Oxidative stress is thought to account for aberrant redox homeostasis and contribute to aging and disease. However, more often than not, administration of antioxidants is ineffective, suggesting that our current understanding of the underlying regulatory processes is incomplete. Recent Advances: Similar to reactive oxygen species and reactive nitrogen species, reactive sulfur species are now emerging as important signaling molecules, targeting regulatory cysteine redox switches in proteins, affecting gene regulation, ion transport, intermediary metabolism, and mitochondrial function. To rationalize the complexity of chemical interactions of reactive species with themselves and their targets and help define their role in systemic metabolic control, we here introduce a novel integrative concept defined as the reactive species interactome (RSI). The RSI is a primeval multilevel redox regulatory system whose architecture, together with the physicochemical characteristics of its constituents, allows efficient sensing and rapid adaptation to environmental changes and various other stressors to enhance fitness and resilience at the local and whole-organism level. Critical Issues: To better characterize the RSI-related processes that determine fluxes through specific pathways and enable integration, it is necessary to disentangle the chemical biology and activity of reactive species (including precursors and reaction products), their targets, communication systems, and effects on cellular, organ, and whole-organism bioenergetics using system-level/network analyses. Future Directions: Understanding the mechanisms through which the RSI operates will enable a better appreciation of the possibilities to modulate the entire biological system; moreover, unveiling molecular signatures that characterize specific environmental challenges or other forms of stress will provide new prevention/intervention opportunities for personalized medicine. Antioxid. Redox Signal. 27, 684–712. PMID:28398072

Transition of late-stage effector T cells to CD27+ CD28+ tumor-reactive effector memory T cells in humans after adoptive cell transfer therapy

PubMed Central

Powell, Daniel J.; Dudley, Mark E.; Robbins, Paul F.; Rosenberg, Steven A.

2007-01-01

In humans, the pathways of memory T-cell differentiation remain poorly defined. Recently, adoptive cell transfer (ACT) of tumor-reactive T lymphocytes to metastatic melanoma patients after nonmyeloablative chemotherapy has resulted in persistence of functional, tumor-reactive lymphocytes, regression of disease, and induction of melanocyte-directed autoimmunity in some responding patients. In the current study, longitudinal phenotypic analysis was performed on melanoma antigen–specific CD8+ T cells during their transition from in vitro cultured effector cells to long-term persistent memory cells following ACT to 6 responding patients. Tumor-reactive T cells used for therapy were generally late-stage effector cells with a CD27Lo CD28Lo CD45RA− CD62 ligand− (CD62L−) CC chemokine receptor 7− (CCR7−) interleukin-7 receptor αLo (IL-7RαLo) phenotype. After transfer, rapid up-regulation and continued expression of IL-7Rα in vivo suggested an important role for IL-7R in immediate and long-term T-cell survival. Although the tumor antigen–specific T-cell population contracted between 1 and 4 weeks after transfer, stable numbers of CD27+ CD28+ tumor-reactive T cells were maintained, demonstrating their contribution to the development of long-term, melanoma-reactive memory CD8+ T cells in vivo. At 2 months after transfer, melanoma-reactive T cells persisted at high levels and displayed an effector memory phenotype, including a CD27+ CD28+ CD62L− CCR7− profile, which may explain in part their ability to mediate tumor destruction. PMID:15345595

Complex auditory behaviour emerges from simple reactive steering

NASA Astrophysics Data System (ADS)

Hedwig, Berthold; Poulet, James F. A.

2004-08-01

The recognition and localization of sound signals is fundamental to acoustic communication. Complex neural mechanisms are thought to underlie the processing of species-specific sound patterns even in animals with simple auditory pathways. In female crickets, which orient towards the male's calling song, current models propose pattern recognition mechanisms based on the temporal structure of the song. Furthermore, it is thought that localization is achieved by comparing the output of the left and right recognition networks, which then directs the female to the pattern that most closely resembles the species-specific song. Here we show, using a highly sensitive method for measuring the movements of female crickets, that when walking and flying each sound pulse of the communication signal releases a rapid steering response. Thus auditory orientation emerges from reactive motor responses to individual sound pulses. Although the reactive motor responses are not based on the song structure, a pattern recognition process may modulate the gain of the responses on a longer timescale. These findings are relevant to concepts of insect auditory behaviour and to the development of biologically inspired robots performing cricket-like auditory orientation.

Clarifying relations between dispositional aggression and brain potential response: overlapping and distinct contributions of impulsivity and stress reactivity.

PubMed

Venables, Noah C; Patrick, Christopher J; Hall, Jason R; Bernat, Edward M

2011-03-01

Impulsive-aggressive individuals exhibit deficits in amplitude of the P3 brain potential response, however, it remains unclear how separable dispositional traits account for this association. The current study sought to clarify the basis of this association by examining contributions of trait impulsiveness and stress reactivity to the observed relationship between dispositional aggression and amplitude of the P3 brain potential response in a visual novelty-oddball procedure. A significant negative association was found between aggressiveness and amplitude of P3 response to both target and novel stimuli over frontal-central scalp sites. Impulsivity showed a parallel inverse relationship with P3 amplitude, attributable to its overlap with dispositional aggression. In contrast, stress reactivity did not exhibit a zero-order association with P3 amplitude, but modestly predicted P3 in a positive direction after accounting for its overlap with aggression. Results are discussed in terms of their implications for individual difference variables and brain processes underlying impulsive-aggressive behavior. Copyright © 2011 Elsevier B.V. All rights reserved.

Using qualitative maps to direct reactive robots

NASA Technical Reports Server (NTRS)

Bertin, Randolph; Pendleton, Tom

1992-01-01

The principal advantage of mobile robots is that they are able to go to specific locations to perform useful tasks rather than have the tasks brought to them. It is important therefore that the robot be used to reach desired locations efficiently and reliably. A mobile robot whose environment extends significantly beyond its sensory horizon must maintain a representation of the environment, a map, in order to attain these efficiency and reliability requirements. We believe that qualitative mapping methods provide useful and robust representation schemes and that such maps may be used to direct the actions of a reactively controlled robot. In this paper we describe our experience in employing qualitative maps to direct, through the selection of desired control strategies, a reactive-behavior based robot. This mapping capability represents the development of one aspect of a successful deliberative/reactive hybrid control architecture.

Modification of Agility Running Technique in Reaction to a Defender in Rugby Union

PubMed Central

Wheeler, Keane W.; Sayers, Mark G.L.

2010-01-01

Three-dimensional kinematic analysis examined agility running technique during pre-planned and reactive performance conditions specific to attacking ball carries in rugby union. The variation to running technique of 8 highly trained rugby union players was compared between agility conditions (pre-planned and reactive) and also agility performance speeds (fast, moderate and slow). Kinematic measures were used to determine the velocity of the centre of mass (COM) in the anteroposterior (running speed) and mediolateral (lateral movement speed) planes. The position of foot-strike and toe-off was also examined for the step prior to the agility side- step (pre-change of direction phase) and then the side-step (change of direction phase). This study demonstrated that less lateral movement speed towards the intended direction change occurred during reactive compared to pre-planned conditions at pre-change of direction (0.08 ± 0.28 m·s-1 and 0.42 ± 0.25 m·s-1, respectively) and change of direction foot-strikes (0.25 ± 0.42 m·s-1 and 0.69 ± 0.43 m·s-1, respectively). Less lateral movement speed during reactive conditions was associated with greater lateral foot displacement (44.52 ± 6.10% leg length) at the change of direction step compared to pre-planned conditions (41.35 ± 5.85%). Importantly, the anticipation abilities during reactive conditions provided a means to differentiate between speeds of agility performance, with faster performances displaying greater lateral movement speed at the change of direction foot- strike (0.52 ± 0.34 m·s-1) compared to moderate (0.20 ± 0.37 m·s-1) and slow (-0.08 ± 0.31 m·s-1). The changes to running technique during reactive conditions highlight the need to incorporate decision-making in rugby union agility programs. Key points Changes to running technique occur when required to make a decision. Fast agility performers use different stepping strategies in reactive conditions. Decision-making must be incorporated in agility training programs. PMID:24149639

Directly reactivated, but not indirectly reactivated, memories undergo reconsolidation in the amygdala

PubMed Central

Dębiec, Jacek; Doyère, Valérie; Nader, Karim; LeDoux, Joseph E.

2006-01-01

Memory consolidation refers to a process by which newly learned information is made resistant to disruption. Traditionally, consolidation has been viewed as an event that occurs once in the life of a memory. However, considerable evidence now indicates that consolidated memories, when reactivated through retrieval, become labile (susceptible to disruption) again and undergo reconsolidation. Because memories are often interrelated in complex associative networks rather than stored in isolation, a key question is whether reactivation of one memory makes associated memories labile in a way that requires reconsolidation. We tested this in rats by creating interlinked associative memories using a second-order fear-conditioning task. We found that directly reactivated memories become labile, but indirectly reactivated (i.e., associated) memories do not. This suggests that memory reactivation produces content-limited rather than wholesale changes in a memory and its associations and explains why each time a memory is retrieved and updated, the entire associative structure of the memory is not grossly altered. PMID:16492789

Fear reactivation prior to exposure therapy: does it facilitate the effects of VR exposure in a randomized clinical sample?

PubMed

Shiban, Youssef; Brütting, Johanna; Pauli, Paul; Mühlberger, Andreas

2015-03-01

The current study is the first to examine whether reactivation of fear memory prior to exposure therapy reduces relapse in a randomized clinical sample. In a standardized treatment protocol combining virtual reality and in-vivo exposure, patients underwent a fear reactivation procedure using a virtual spider 10 min prior to a virtual reality (VR) exposure (reactivation group: RG, n = 15). A control group (CG, n = 17) was exposed to a virtual plant 10 min prior to the VR exposure. Outcome measures were a VR spontaneous recovery test (SRT) and in-vivo a behavioral avoidance test assessed 24 h after VR exposure. One week later an in-vivo exposure session followed. Additionally, a follow-up using psychometric assessment was conducted six months after the first session. Both groups benefitted significantly and equally from the combined treatment, and importantly, the SRT revealed no return of fear in both groups. Furthermore, follow-up tests showed long-term treatment effects with no group differences. Due to different study components (VR treatment and in-vivo), we were not able to determine which treatment module was mainly responsible for the long-term treatment effect. Furthermore, no direct measure of memory destabilization was possible in this study. Our treatment package was highly effective in reducing phobic fear up to 6 months following treatment. Explicit fear reactivation prior to exposure was not beneficial in VR exposure treatment, possibly due to a failure to induce a memory destabilization or due to an implicit fear reactivation prior to treatment in both groups.

Impact of sleep restriction versus idealized sleep on emotional experience, reactivity and regulation in healthy adolescents.

PubMed

Reddy, Radhika; Palmer, Cara A; Jackson, Christine; Farris, Samantha G; Alfano, Candice A

2017-08-01

Sleep loss is associated with affective disturbances and disorders; however, there is limited understanding of specific mechanisms underlying these links, especially in adolescence. The current study tested the effects of sleep restriction versus idealized sleep on adolescents' emotional experience, reactivity and regulation (specifically cognitive reappraisal). Following 1 week of sleep monitoring, healthy adolescents (n = 42; ages 13-17 years) were randomized to 1 night of sleep restriction (4 h) or idealized sleep (9.5 h). The following day, adolescents provided self-reports of affect and anxiety and completed a laboratory-based task to assess: (1) emotional reactivity in response to positive, negative, and neutral images from the International Affective Picture System (IAPS); and (2) ability to use cognitive reappraisal to decrease negative emotional responses. Large effects were observed for the adverse impact of sleep restriction on positive affect and anxiety as well as a medium-sized effect for negative affect, compared to the idealized sleep condition. Subjective reactivity to positive and neutral images did not differ between the groups, but a moderate effect was detected for reactivity to negative images whereby sleep-restricted teens reported greater reactivity. Across both sleep conditions, use of cognitive reappraisal down-regulated negative emotion effectively; however, sleep restriction did not impact upon adolescents' ability to use this strategy. These findings add to a growing body of literature demonstrating the deleterious effects of sleep restriction on aspects of emotion and highlight directions for future research in adolescents. © 2016 European Sleep Research Society.

Using cheminformatics to predict cross reactivity of “designer drugs” to their currently available immunoassays

PubMed Central

2014-01-01

Background A challenge for drug of abuse testing is presented by ‘designer drugs’, compounds typically discovered by modifications of existing clinical drug classes such as amphetamines and cannabinoids. Drug of abuse screening immunoassays directed at amphetamine or methamphetamine only detect a small subset of designer amphetamine-like drugs, and those immunoassays designed for tetrahydrocannabinol metabolites generally do not cross-react with synthetic cannabinoids lacking the classic cannabinoid chemical backbone. This suggests complexity in understanding how to detect and identify whether a patient has taken a molecule of one class or another, impacting clinical care. Methods Cross-reactivity data from immunoassays specifically targeting designer amphetamine-like and synthetic cannabinoid drugs was collected from multiple published sources, and virtual chemical libraries for molecular similarity analysis were built. The virtual library for synthetic cannabinoid analysis contained a total of 169 structures, while the virtual library for amphetamine-type stimulants contained 288 compounds. Two-dimensional (2D) similarity for each test compound was compared to the target molecule of the immunoassay undergoing analysis. Results 2D similarity differentiated between cross-reactive and non-cross-reactive compounds for immunoassays targeting mephedrone/methcathinone, 3,4-methylenedioxypyrovalerone, benzylpiperazine, mephentermine, and synthetic cannabinoids. Conclusions In this study, we applied 2D molecular similarity analysis to the designer amphetamine-type stimulants and synthetic cannabinoids. Similarity calculations can be used to more efficiently decide which drugs and metabolites should be tested in cross-reactivity studies, as well as to design experiments and potentially predict antigens that would lead to immunoassays with cross reactivity for a broader array of designer drugs. PMID:24851137

Electromagnetic micropores: fabrication and operation.

PubMed

Basore, Joseph R; Lavrik, Nickolay V; Baker, Lane A

2010-12-21

We describe the fabrication and characterization of electromagnetic micropores. These devices consist of a micropore encompassed by a microelectromagnetic trap. Fabrication of the device involves multiple photolithographic steps, combined with deep reactive ion etching and subsequent insulation steps. When immersed in an electrolyte solution, application of a constant potential across the micropore results in an ionic current. Energizing the electromagnetic trap surrounding the micropore produces regions of high magnetic field gradients in the vicinity of the micropore that can direct motion of a ferrofluid onto or off of the micropore. This results in dynamic gating of the ion current through the micropore structure. In this report, we detail fabrication and characterize the electrical and ionic properties of the prepared electromagnetic micropores.

Reactivity of bromoselenophenes in palladium-catalyzed direct arylations.

PubMed

Skhiri, Aymen; Ben Salem, Ridha; Soulé, Jean-François; Doucet, Henri

2017-01-01

The reactivity of 2-bromo- and 2,5-dibromoselenophenes in Pd-catalyzed direct heteroarylation was investigated. From 2-bromoselenophene, only the most reactive heteroarenes could be employed to prepare 2-heteroarylated selenophenes; whereas, 2,5-dibromoselenophene generally gave 2,5-di(heteroarylated) selenophenes in high yields using both thiazole and thiophene derivatives. Moreover, sequential catalytic C2 heteroarylation, bromination, catalytic C5 arylation reactions allowed the synthesis of unsymmetrical 2,5-di(hetero)arylated selenophene derivatives in three steps from selenophene.

Effects of Preventative Ankle Taping on Planned Change-of-Direction and Reactive Agility Performance and Ankle Muscle Activity in Basketballers

PubMed Central

Jeffriess, Matthew D.; Schultz, Adrian B.; McGann, Tye S.; Callaghan, Samuel J.; Lockie, Robert G.

2015-01-01

This study investigated the effects of preventative ankle taping on planned change-of-direction and reactive agility performance and peak ankle muscle activity in basketballers. Twenty male basketballers (age = 22.30 ± 3.97 years; height = 1.84 ± 0.09 meters; body mass = 85.96 ± 11.88 kilograms) with no ankle pathologies attended two testing sessions. Within each session, subjects completed six planned and six reactive randomized trials (three to the left and three to the right for each condition) of the Y-shaped agility test, which was recorded by timing lights. In one session, subjects had both ankles un-taped. In the other, both ankles were taped using a modified subtalar sling. Peak tibialis anterior, peroneus longus (PL), peroneus brevis (PB), and soleus muscle activity was recorded for both the inside and outside legs across stance phase during the directional change, which was normalized against 10-meter sprint muscle activity (nEMG). Both the inside and outside cut legs during the change-of-direction step were investigated. Repeated measures ANOVA determined performance time and nEMG differences between un-taped and taped conditions. There were no differences in planned change-of-direction or reactive agility times between the conditions. Inside cut leg PL nEMG decreased when taped for the planned left, reactive left, and reactive right cuts (p = 0.01). Outside leg PB and soleus nEMG increased during the taped planned left cut (p = 0.02). There were no other nEMG changes during the cuts with taping. Taping did not affect change-of-direction or agility performance. Inside leg PL activity was decreased, possibly due to the tape following the line of muscle action. This may reduce the kinetic demand for the PL during cuts. In conclusion, ankle taping did not significantly affect planned change-of-direction or reactive agility performance, and did not demonstrate large changes in activity of the muscle complex in healthy basketballers. Key points Ankle taping using the modified subtalar sling will not affect planned change-of-direction or reactive agility performance as measured by the Y-shaped agility test in healthy male basketball players. Ankle taping using the modified subtalar sling will also generally not affect the activity of the muscles about the ankle. There was some indication for reductions in the activity of the PL in the inside leg of certain cuts. The tape used for the modified subtalar sling may have supported the line of action of the PL, which could reduce the kinetic demand placed on this muscle, and provide a potential fatigue-reducing component for cutting actions. The subtalar sling taping of the ankle in healthy basketball players did not have any adverse effects on the muscle activity of the ankle-foot complex during planned change-of-direction or reactive agility performance tasks. PMID:26664285

The reactivation time in the treatment of AMD: a forgotten key parameter?

PubMed

Real, J P; Luna, J D; Palma, S D

2018-06-01

Summarize and compare the available evidence on the reactivation times in patients with age-related macular degeneration treated with Ranibizumab (RNB). Systematic review of studies that reported the reactivation time of patients (direct method) or the number of injections received in a certain period of follow-up (indirect method). Only 18 of 89 selected studies reported the average reactivation time of patients in a manifest form, without the need of any calculation. The average calculated, weighted reactivation time was 101.8 days with the direct method and 99.8 days in the indirect method (84 studies included). With both methods, it was found that the average reactivation time of the RCTs was between 2 and 3 weeks less than the average time identified in the observational studies. These differences are also reflected in the clinical results, there being a correlation between the number of doses received and the change in BCVA. The analysis of 11 comparative studies showed a difference in reactivation times between patients treated with RNB or Bevacizumab (BVZ). There are few direct studies of reactivation time, but calculation from the PRN dose number turns out to be a good approximation for retrospective study of the variable. The use of the PRN, with criteria not based on optical coherence tomography scans, delays the application of doses between 2 or 3 weeks, and patients suffer loss of clinical benefits. RNB enables patients to receive less injections than BVZ throughout treatment.

Physiological Reactivity Moderates the Association between Parental Directing and Young Adolescent Friendship Adjustment

ERIC Educational Resources Information Center

Tu, Kelly M.; Erath, Stephen A.; Pettit, Gregory S.; El-Sheikh, Mona

2014-01-01

This study examined whether the longitudinal association between parental directing of friendships (i.e., encouraging or discouraging certain friendships) and young adolescents' friendship adjustment (i.e., friendship quality and friends' positive characteristics) was moderated by skin conductance level reactivity (SCLR) to peer stress.…

Combined experimental and theoretical description of direct current magnetron sputtering of Al by Ar and Ar/N2 plasma

NASA Astrophysics Data System (ADS)

Trieschmann, Jan; Ries, Stefan; Bibinov, Nikita; Awakowicz, Peter; Mráz, Stanislav; Schneider, Jochen M.; Mussenbrock, Thomas

2018-05-01

Direct current magnetron sputtering of Al by Ar and Ar/N2 low pressure plasmas was characterized by experimental and theoretical means in a unified consideration. Experimentally, the plasmas were analyzed by optical emission spectroscopy, while the film deposition rate was determined by weight measurements and laser optical microscopy, and the film composition by energy dispersive x-ray spectroscopy. Theoretically, a global particle and power balance model was used to estimate the electron temperature T e and the electron density n e of the plasma at constant discharge power. In addition, the sputtering process and the transport of the sputtered atoms were described using Monte Carlo models—TRIDYN and dsmcFoam, respectively. Initially, the non-reactive situation is characterized based on deposition experiment results, which are in agreement with predictions from simulations. Subsequently, a similar study is presented for the reactive case. The influence of the N2 addition is found to be twofold, in terms of (i) the target and substrate surface conditions (e.g., sputtering, secondary electron emission, particle sticking) and (ii) the volumetric changes of the plasma density n e governing the ion flux to the surfaces (e.g., due to additional energy conversion channels). It is shown that a combined experimental/simulation approach reveals a physically coherent and, in particular, quantitative understanding of the properties (e.g., electron density and temperature, target surface nitrogen content, sputtered Al density, deposited mass) involved in the deposition process.

Current status of NADPH oxidase research in cardiovascular pharmacology.

PubMed

Rodiño-Janeiro, Bruno K; Paradela-Dobarro, Beatriz; Castiñeiras-Landeira, María Isabel; Raposeiras-Roubín, Sergio; González-Juanatey, José R; Alvarez, Ezequiel

2013-01-01

The implications of reactive oxygen species in cardiovascular disease have been known for some decades. Rationally, therapeutic antioxidant strategies combating oxidative stress have been developed, but the results of clinical trials have not been as good as expected. Therefore, to move forward in the design of new therapeutic strategies for cardiovascular disease based on prevention of production of reactive oxygen species, steps must be taken on two fronts, ie, comprehension of reduction-oxidation signaling pathways and the pathophysiologic roles of reactive oxygen species, and development of new, less toxic, and more selective nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors, to clarify both the role of each NADPH oxidase isoform and their utility in clinical practice. In this review, we analyze the value of NADPH oxidase as a therapeutic target for cardiovascular disease and the old and new pharmacologic agents or strategies to prevent NADPH oxidase activity. Some inhibitors and different direct or indirect approaches are available. Regarding direct NADPH oxidase inhibition, the specificity of NADPH oxidase is the focus of current investigations, whereas the chemical structure-activity relationship studies of known inhibitors have provided pharmacophore models with which to search for new molecules. From a general point of view, small-molecule inhibitors are preferred because of their hydrosolubility and oral bioavailability. However, other possibilities are not closed, with peptide inhibitors or monoclonal antibodies against NADPH oxidase isoforms continuing to be under investigation as well as the ongoing search for naturally occurring compounds. Likewise, some different approaches include inhibition of assembly of the NADPH oxidase complex, subcellular translocation, post-transductional modifications, calcium entry/release, electron transfer, and genetic expression. High-throughput screens for any of these activities could provide new inhibitors. All this knowledge and the research presently underway will likely result in development of new drugs for inhibition of NADPH oxidase and application of therapeutic approaches based on their action, for the treatment of cardiovascular disease in the next few years.

Current status of NADPH oxidase research in cardiovascular pharmacology

PubMed Central

Rodiño-Janeiro, Bruno K; Paradela-Dobarro, Beatriz; Castiñeiras-Landeira, María Isabel; Raposeiras-Roubín, Sergio; González-Juanatey, José R; Álvarez, Ezequiel

2013-01-01

The implications of reactive oxygen species in cardiovascular disease have been known for some decades. Rationally, therapeutic antioxidant strategies combating oxidative stress have been developed, but the results of clinical trials have not been as good as expected. Therefore, to move forward in the design of new therapeutic strategies for cardiovascular disease based on prevention of production of reactive oxygen species, steps must be taken on two fronts, ie, comprehension of reduction-oxidation signaling pathways and the pathophysiologic roles of reactive oxygen species, and development of new, less toxic, and more selective nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors, to clarify both the role of each NADPH oxidase isoform and their utility in clinical practice. In this review, we analyze the value of NADPH oxidase as a therapeutic target for cardiovascular disease and the old and new pharmacologic agents or strategies to prevent NADPH oxidase activity. Some inhibitors and different direct or indirect approaches are available. Regarding direct NADPH oxidase inhibition, the specificity of NADPH oxidase is the focus of current investigations, whereas the chemical structure-activity relationship studies of known inhibitors have provided pharmacophore models with which to search for new molecules. From a general point of view, small-molecule inhibitors are preferred because of their hydrosolubility and oral bioavailability. However, other possibilities are not closed, with peptide inhibitors or monoclonal antibodies against NADPH oxidase isoforms continuing to be under investigation as well as the ongoing search for naturally occurring compounds. Likewise, some different approaches include inhibition of assembly of the NADPH oxidase complex, subcellular translocation, post-transductional modifications, calcium entry/release, electron transfer, and genetic expression. High-throughput screens for any of these activities could provide new inhibitors. All this knowledge and the research presently underway will likely result in development of new drugs for inhibition of NADPH oxidase and application of therapeutic approaches based on their action, for the treatment of cardiovascular disease in the next few years. PMID:23983473

A fluorescence high throughput screening method for the detection of reactive electrophiles as potential skin sensitizers

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

Avonto, Cristina; Chittiboyina, Amar G.; Rua, Diego

2015-12-01

Skin sensitization is an important toxicological end-point in the risk assessment of chemical allergens. Because of the complexity of the biological mechanisms associated with skin sensitization, integrated approaches combining different chemical, biological and in silico methods are recommended to replace conventional animal tests. Chemical methods are intended to characterize the potential of a sensitizer to induce earlier molecular initiating events. The presence of an electrophilic mechanistic domain is considered one of the essential chemical features to covalently bind to the biological target and induce further haptenation processes. Current in chemico assays rely on the quantification of unreacted model nucleophiles aftermore » incubation with the candidate sensitizer. In the current study, a new fluorescence-based method, ‘HTS-DCYA assay’, is proposed. The assay aims at the identification of reactive electrophiles based on their chemical reactivity toward a model fluorescent thiol. The reaction workflow enabled the development of a High Throughput Screening (HTS) method to directly quantify the reaction adducts. The reaction conditions have been optimized to minimize solubility issues, oxidative side reactions and increase the throughput of the assay while minimizing the reaction time, which are common issues with existing methods. Thirty-six chemicals previously classified with LLNA, DPRA or KeratinoSens™ were tested as a proof of concept. Preliminary results gave an estimated 82% accuracy, 78% sensitivity, 90% specificity, comparable to other in chemico methods such as Cys-DPRA. In addition to validated chemicals, six natural products were analyzed and a prediction of their sensitization potential is presented for the first time. - Highlights: • A novel fluorescence-based method to detect electrophilic sensitizers is proposed. • A model fluorescent thiol was used to directly quantify the reaction products. • A discussion of the reaction workflow and critical parameters is presented. • The method could provide a useful tool to complement existing chemical assays.« less

Generating carbyne equivalents with photoredox catalysis

NASA Astrophysics Data System (ADS)

Wang, Zhaofeng; Herraiz, Ana G.; Del Hoyo, Ana M.; Suero, Marcos G.

2018-02-01

Carbon has the unique ability to bind four atoms and form stable tetravalent structures that are prevalent in nature. The lack of one or two valences leads to a set of species—carbocations, carbanions, radicals and carbenes—that is fundamental to our understanding of chemical reactivity. In contrast, the carbyne—a monovalent carbon with three non-bonded electrons—is a relatively unexplored reactive intermediate; the design of reactions involving a carbyne is limited by challenges associated with controlling its extreme reactivity and the lack of efficient sources. Given the innate ability of carbynes to form three new covalent bonds sequentially, we anticipated that a catalytic method of generating carbynes or related stabilized species would allow what we term an ‘assembly point’ disconnection approach for the construction of chiral centres. Here we describe a catalytic strategy that generates diazomethyl radicals as direct equivalents of carbyne species using visible-light photoredox catalysis. The ability of these carbyne equivalents to induce site-selective carbon-hydrogen bond cleavage in aromatic rings enables a useful diazomethylation reaction, which underpins sequencing control for the late-stage assembly-point functionalization of medically relevant agents. Our strategy provides an efficient route to libraries of potentially bioactive molecules through the installation of tailored chiral centres at carbon-hydrogen bonds, while complementing current translational late-stage functionalization processes. Furthermore, we exploit the dual radical and carbene character of the generated carbyne equivalent in the direct transformation of abundant chemical feedstocks into valuable chiral molecules.

Plasma emission spectroscopy and its relation to the refractive index of silicon nitride thin films deposited by reactive magnetron sputtering

NASA Astrophysics Data System (ADS)

Sanginés, R.; Abundiz-Cisneros, N.; Hernández Utrera, O.; Diliegros-Godines, C.; Machorro-Mejía, R.

2018-03-01

In this work, we present a thorough study on the relation between the plasma emission and the change of the silicon nitride thin films refractive index. Thin films were grown by reactive magnetron direct current sputtering technique and deposited onto silicon wafers at different fluxes of Ar and N2 and at different working pressures. This procedure, at certain deposition parameters, produced poor quality films, i.e. films with refractive index other than pure Si3N4 films. The emission of the plasma was interrogated in real time by means of optical emission spectroscopy (OES) observing at the vicinity of the trget location. In addition, optical properties of the films were measured by in situ ellipsometric-spectroscopy and then correlated with OES observations. Changes in the film refractive index could be deduced from changes in plasma emission applying a principal component analysis.

Structural-dependent thermal conductivity of aluminium nitride produced by reactive direct current magnetron sputtering

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

Belkerk, B. E.; Soussou, A.; Carette, M.

This Letter reports the thermal conductivity of aluminium nitride (AlN) thin-films deposited by reactive DC magnetron sputtering on single-crystal silicon substrates (100) with varying plasma and magnetic conditions achieving different crystalline qualities. The thermal conductivity of the films was measured at room temperature with the transient hot-strip technique for film thicknesses ranging from 100 nm to 4000 nm. The thermal conductivity was found to increase with the thickness depending on the synthesis conditions and film microstructure. The conductivity in the bulk region of the films, so-called intrinsic conductivity, and the boundary resistance were in the range [120-210] W m{sup -1}more » K{sup -1} and [2-30 Multiplication-Sign 10{sup -9}] K m{sup 2} W{sup -1}, respectively, in good agreement with microstructures analysed by x-ray diffraction, high-resolution-scanning-electron-microscopy, and transmission-electron-microscopy.« less

MicroRNA-155 Reinforces HIV Latency*

PubMed Central

Ruelas, Debbie S.; Chan, Jonathan K.; Oh, Eugene; Heidersbach, Amy J.; Hebbeler, Andrew M.; Chavez, Leonard; Verdin, Eric; Rape, Michael; Greene, Warner C.

2015-01-01

The presence of a small number of infected but transcriptionally dormant cells currently thwarts a cure for the more than 35 million individuals infected with HIV. Reactivation of these latently infected cells may result in three fates: 1) cell death due to a viral cytopathic effect, 2) cell death due to immune clearance, or 3) a retreat into latency. Uncovering the dynamics of HIV gene expression and silencing in the latent reservoir will be crucial for developing an HIV-1 cure. Here we identify and characterize an intracellular circuit involving TRIM32, an HIV activator, and miR-155, a microRNA that may promote a return to latency in these transiently activated reservoir cells. Notably, we demonstrate that TRIM32, an E3 ubiquitin ligase, promotes reactivation from latency by directly modifying IκBα, leading to a novel mechanism of NF-κB induction not involving IκB kinase activation. PMID:25873391

Microscopic Scale Simulation of the Ablation of Fibrous Materials

NASA Technical Reports Server (NTRS)

Lachaud, Jean Romain; Mansour, Nagi N.

2010-01-01

Ablation by oxidation of carbon-fiber preforms impregnated in carbonized phenolic matrix is modeled at microscopic scale. Direct numerical simulations show that the carbonized phenolic matrix ablates in volume leaving the carbon fibers exposed. This is due to the fact that the reactivity of carbonized phenolic is higher than the reactivity of carbon fibers. After the matrix is depleted, the fibers ablate showing progressive reduction of their diameter. The overall material recession occurs when the fibers are consumed. Two materials with the same carbon-fiber preform, density and chemical composition, but with different matrix distributions are studied. These studies show that at moderate temperatures (< 1000 K) the microstructure of the material influences its recession rate; a fact that is not captured by current models that are based on chemical composition only. Surprisingly, the response of these impregnated-fiber materials is weakly dependent on the microstructure at very high temperatures (e.g., Stardust peak heating conditions: 3360K).

Sex differences in physiological reactivity to acute psychosocial stress in adolescence.

PubMed

Ordaz, Sarah; Luna, Beatriz

2012-08-01

Females begin to demonstrate greater negative affective responses to stress than males in adolescence. This may reflect the concurrent emergence of underlying differences in physiological response systems, including corticolimbic circuitries, the hypothalamic-pituitary-adrenal axis (HPAA), and the autonomic nervous system (ANS). This review examines when sex differences in physiological reactivity to acute psychosocial stress emerge and the directionality of these differences over development. Indeed, the literature indicates that sex differences emerge during adolescence and persist into adulthood for all three physiological response systems. However, the directionality of the differences varies by system. The emerging corticolimbic reactivity literature suggests greater female reactivity, particularly in limbic regions densely innervated by gonadal hormone receptors. In contrast, males generally show higher levels of HPAA and ANS reactivity. We argue that the contrasting directionality of corticolimbic and peripheral physiological responses may reflect specific effects of gonadal hormones on distinct systems and also sex differences in evolved behavioral responses that demand different levels of peripheral physiological activation. Studies that examine both subjective reports of negative affect and physiological responses indicate that beginning in adolescence, females respond to acute stressors with more intense negative affect than males despite their comparatively lower peripheral physiological responses. This dissociation is not clearly explained by sex differences in the strength of the relationship between physiological and subjective responses. We suggest that females' greater subjective responsivity may instead arise from a greater activity in brain regions that translate stress responses to subjective awareness in adolescence. Future research directions include investigations of the role of pubertal hormones in physiological reactivity across all systems, examining the relationship of corticolimbic reactivity and negative affect, and sex differences in emotion regulation processes. Copyright © 2012 Elsevier Ltd. All rights reserved.

Sex differences in physiological reactivity to acute psychosocial stress in adolescence

PubMed Central

Ordaz, Sarah; Luna, Beatriz

2012-01-01

Summary Females begin to demonstrate greater negative affective responses to stress than males in adolescence. This may reflect the concurrent emergence of underlying differences in physiological response systems, including corticolimbic circuitries, the hypothalamic—pituitary— adrenal axis (HPAA), and the autonomic nervous system (ANS). This review examines when sex differences in physiological reactivity to acute psychosocial stress emerge and the directionality of these differences over development. Indeed, the literature indicates that sex differences emerge during adolescence and persist into adulthood for all three physiological response systems. However, the directionality of the differences varies by system. The emerging corti-colimbic reactivity literature suggests greater female reactivity, particularly in limbic regions densely innervated by gonadal hormone receptors. In contrast, males generally show higher levels of HPAA and ANS reactivity. We argue that the contrasting directionality of corticolimbic and peripheral physiological responses may reflect specific effects of gonadal hormones on distinct systems and also sex differences in evolved behavioral responses that demand different levels of peripheral physiological activation. Studies that examine both subjective reports of negative affect and physiological responses indicate that beginning in adolescence, females respond to acute stressors with more intense negative affect than males despite their comparatively lower peripheral physiological responses. This dissociation is not clearly explained by sex differences in the strength of the relationship between physiological and subjective responses. We suggest that females' greater subjective responsivity may instead arise from a greater activity in brain regions that translate stress responses to subjective awareness in adolescence. Future research directions include investigations of the role of pubertal hormones in physiological reactivity across all systems, examining the relationship of corticolimbic reactivity and negative affect, and sex differences in emotion regulation processes. PMID:22281210

Quantification of Hydroxyl Radical reactivity in the urban environment using the Comparative Reactivity Method (CRM)

NASA Astrophysics Data System (ADS)

Panchal, Rikesh; Monks, Paul

2015-04-01

Hydroxyl (OH) radicals play an important role in 'cleansing' the atmosphere of many pollutants such as, NOx, CH4 and various VOCs, through oxidation. To measure the reactivity of OH, both the sinks and sources of OH need to be quantified, and currently the overall sinks of OH seem not to be fully constrained. In order to measure the total rate loss of OH in an ambient air sample, all OH reactive species must be considered and their concentrations and reaction rate coefficients with OH known. Using the method pioneered by Sinha and Williams at the Max Plank Institute Mainz, the Comparative Reactivity Method (CRM) which directly quantifies total OH reactivity in ambient air without the need to consider the concentrations of individual species within the sample that can react with OH, has been developed and applied in a urban setting. The CRM measures the concentration of a reactive species that is present only in low concentrations in ambient air, in this case pyrrole, flowing through a reaction vessel and detected using Proton Transfer Reaction - Mass Spectrometry (PTR-MS). The poster will show a newly developed and tested PTR-TOF-MS system for CRM. The correction regime will be detailed to account for the influence of the varying humidity between ambient air and clean air on the pyrrole signal. Further, examination of the sensitivity dependence of the PTR-MS as a function of relative humidity and H3O+(H2O) (m/z=37) cluster ion allows the correction for the humidity variation, between the clean humid air entering the reaction vessel and ambient air will be shown. NO, present within ambient air, is also a potential interference and can cause recycling of OH, resulting in an overestimation of OH reactivity. Tests have been conducted on the effects of varying NO concentrations on OH reactivity and a correction factor determined for application to data when sampling ambient air. Finally, field tests in the urban environment at the University of Leicester will be shown coupled to an examination of trends in OH reactivity and other air quality markers such NOx and black carbon.

Adolescents' eating behaviour in general and in the peer context: testing the prototype-willingness model.

PubMed

Dohnke, Birte; Steinhilber, Amina; Fuchs, Tanja

2015-01-01

To investigate the prototype-willingness model (PWM) for eating behaviour in general and in the peer context in order to gain further evidence on the PWM and social-reactive processes in adolescents' eating behaviour. A longitudinal study was conducted. PWM variables for unhealthy and healthy eating were assessed at baseline in 356 adolescents (mean age 12.61 years). Eating behaviour was measured four weeks after baseline by two indicators: general eating pattern index (self-report) and consumption of unhealthy and healthy snacks in the peer context (behavioural observation). For both, structural equation models were conducted introducing PWM variables for either unhealthy or healthy eating. The PWM was mainly confirmed for the eating pattern index; intention, willingness and prototype perception had direct effects. Differences between unhealthy and healthy eating were found. Moreover, the PWM contributed to the prediction of healthy, but not unhealthy, snack consumption over and above current hunger; willingness had a direct effect. The PWM can be applied to predict and understand adolescents' eating behaviour. Social-reactive processes, namely willingness and prototype perception, are behavioural determinants that should be considered in theory and as novel targets in health promotion interventions.

Direct analysis of quaternary alkaloids by in situ reactive desorption corona beam ionization MS.

PubMed

Hou, Yulan; Wu, Tingting; Liu, Yaru; Wang, Hua; Chen, Yingzhuang; Chen, Bo; Sun, Wenjian

2014-10-21

The direct detection of quaternary alkaloids by atmospheric pressure chemical ionization (APCI)-base ambient MS is difficult because of their poor volatility. In this study, a reactive protocol was developed for the in situ determination of quaternary alkaloids using desorption corona beam ionization (DCBI) mass spectrometry (MS). The model compounds of 8 quaternary alkaloids including sanguinarine, chelerythrine, cyclanoline, nitidine, coptisine, jatrorrhizine, berberine, palmatine and 2 tertiary alkaloids including protopine and allocryptopine were investigated in different states such as on a polytetrafluoroethylene (PTFE) plate, in raw herbal materials, and in silica gel. After various reactive reagents were studied, the mixture of saturated aqueous NaOH solution and CH3OH solvent (3 : 7, v/v) was selected as the optimized reactive reagent for the reactive DCBI-MS detection. All the target molecules can be detected with high sensitivity. On a PTFE plate the limits of detection were 0.0795, 0.1060, 0.4860, 0.9665, 0.8879, 0.3987, 0.5557, 0.4591, 0.0889, and 0.1929 mg L(-1) for sanguinarine, chelerythrine, cyclanoline, nitidine, coptisine, jatrorrhizine, berberine, palmatine, protopine, and allocryptopine, respectively. The reactive protocol was also applied to the direct detection of raw herbal materials and thin layer chromatography successfully.

Physiological reactivity in children of Oklahoma City bombing survivors 7 years postdisaster: a pilot study.

PubMed

Pfefferbaum, Betty; Tucker, Phebe; North, Carol S; Jeon-Slaughter, Haekyung

2011-08-01

Relatively few studies of children exposed to trauma have used objective indicators such as heart rate and blood pressure measurements to assess physiological reactivity. This pilot study examined physiological reactivity (heart rate, systolic blood pressure, and diastolic blood pressure) and emotional indicators (posttraumatic stress and depressive symptoms) in 17 children of directly exposed Oklahoma City bombing survivors and in 17 demographically matched community comparison children, 7 years after the incident. Despite generally low levels of subjectively reported posttraumatic stress and depressive symptoms 7 years after the disaster, the children of survivors showed heightened objectively measured physiological reactivity relative to the comparison group. The extent to which this heightened physiological reactivity in the children of survivors was pathologic is unclear. Only 1 participant reported high levels of posttraumatic stress and depressive symptoms; this individual also demonstrated physiological reactivity. Results suggest children of disaster survivors may experience physiological reactivity despite absence of direct exposure to the trauma or acknowledgement of symptoms. These findings indicate the physiological effects of trauma may endure separate from subjective affect in the offspring of highly exposed disaster survivors. More research is needed to determine the potential consequences of persistent physiological reactivity.

The influence of physical and cognitive factors on reactive agility performance in men basketball players.

PubMed

Scanlan, Aaron; Humphries, Brendan; Tucker, Patrick S; Dalbo, Vincent

2014-01-01

This study explored the influence of physical and cognitive measures on reactive agility performance in basketball players. Twelve men basketball players performed multiple sprint, Change of Direction Speed Test, and Reactive Agility Test trials. Pearson's correlation analyses were used to determine relationships between the predictor variables (stature, mass, body composition, 5-m, 10-m and 20-m sprint times, peak speed, closed-skill agility time, response time and decision-making time) and reactive agility time (response variable). Simple and stepwise regression analyses determined the individual influence of each predictor variable and the best predictor model for reactive agility time. Morphological (r = -0.45 to 0.19), sprint (r = -0.40 to 0.41) and change-of-direction speed measures (r = 0.43) had small to moderate correlations with reactive agility time. Response time (r = 0.76, P = 0.004) and decision-making time (r = 0.58, P = 0.049) had large to very large relationships with reactive agility time. Response time was identified as the sole predictor variable for reactive agility time in the stepwise model (R(2) = 0.58, P = 0.004). In conclusion, cognitive measures had the greatest influence on reactive agility performance in men basketball players. These findings suggest reaction and decision-making drills should be incorporated in basketball training programmes.

Stacking fault related luminescence in GaN nanorods.

PubMed

Forsberg, M; Serban, A; Poenaru, I; Hsiao, C-L; Junaid, M; Birch, J; Pozina, G

2015-09-04

Optical and structural properties are presented for GaN nanorods (NRs) grown in the [0001] direction on Si(111) substrates by direct-current reactive magnetron sputter epitaxy. Transmission electron microscopy (TEM) reveals clusters of dense stacking faults (SFs) regularly distributed along the c-axis. A strong emission line at ∼3.42 eV associated with the basal-plane SFs has been observed in luminescence spectra. The optical signature of SFs is stable up to room temperatures with the activation energy of ∼20 meV. Temperature-dependent time-resolved photoluminescence properties suggest that the recombination mechanism of the 3.42 eV emission can be understood in terms of multiple quantum wells self-organized along the growth axis of NRs.

Association of T-cell reactivity with beta-cell function in recent onset type 1 diabetes patients.

PubMed

Pfleger, Christian; Meierhoff, Guido; Kolb, Hubert; Schloot, Nanette C

2010-03-01

The aim of the current study was to investigate whether autoantigen directed T-cell reactivity relates to beta-cell function during the first 78 weeks after diagnosis of type 1 diabetes. 50 adults and 49 children (mean age 27.3 and 10.9 years respectively) with recent onset type 1 diabetes who participated in a placebo-controlled trial of immune intervention with DiaPep277 were analyzed. Secretion of interferon (IFN)-gamma, interleukin (IL)-5, IL-13 and IL-10 by single peripheral mononuclear cells (PBMC) upon stimulation with islet antigens GAD65, heat shock protein 60 (Hsp60) protein-tyrosine-phosphatase-like-antigen (pIA2) or tetanus toxoid (TT) was determined applying ELISPOT; beta-cell function was evaluated by glucagon stimulated C-peptide. Multivariate regression analysis was applied. In general, number of islet antigen-reactive cells decreased over 78 weeks in both adults and children, whereas reactivity to TT was not reduced. In addition, there was an association between the quality of immune cell responses and beta-cell function. Overall, increased responses by IFN-gamma secreting cells were associated with lower beta-cell function whereas IL-5, IL-13 and IL-10 cytokine responses were positively associated with beta-cell function in adults and children. Essentially, the same results were obtained with three different models of regression analysis. The number of detectable islet-reactive immune cells decreases within 1-2 years after diagnosis of type 1 diabetes. Cytokine production by antigen-specific PBMC reactivity is related to beta-cell function as measured by stimulated C-peptide. Cellular immunity appears to regress soon after disease diagnosis and begin of insulin therapy. Copyright 2009 Elsevier Ltd. All rights reserved.

Immunomodulation: the future cure for allergic diseases.

PubMed

Tsitoura, Daphne C; Tassios, Yannis

2006-11-01

Allergies are the result of aberrant immune reactivity against common innocuous environmental proteins (allergens). A pivotal component of allergic pathogenesis is the generation of allergen-specific Th cells with an effector phenotype. These Th cells activate a complex immune cascade that triggers the release of potent mediators and enhances the mobilization of several inflammatory cells types, which in turn elicit the acute allergic reactions and promote the development of chronic inflammation. The current therapies for allergic diseases focus primarily on pharmacological control of symptoms and suppression of inflammation. This approach is beneficial, but not curative, since the underlying immune pathology is not inhibited. In an attempt to develop more effective therapeutic strategies, the scientific interest has been directed toward methods down-modulating the immune mechanisms that initiate and maintain the allergic cascade. Today, the only widely used disease-modifying form of allergy treatment is the specific immunotherapy with allergen extracts. More recently the use of anti-IgE has been approved for patients with allergic asthma. Other immunomodulatory methods being currently explored are the administration of microbial adjuvants that inhibit Th2 reactivity and the design of molecules that interrupt the activity of key allergic cytokines, chemokines, or other Th2 effector mediators.

What happens after the activation of ascaridole? Reactive compounds and their implications for skin sensitization

USDA-ARS?s Scientific Manuscript database

To replace animal testing and to improve the prediction of skin sensitization, significant attention has been directed to the use of alternative methods. Along with induction of Nrf2 target gene and upregulation of CD86 and C54 markers, the direct peptide reactivity assay (DPRA), the regulatory agen...

Identification of the critical residues responsible for differential reactivation of the triosephosphate isomerases of two trypanosomes

PubMed Central

Rodríguez-Bolaños, Monica; Cabrera, Nallely

2016-01-01

The reactivation of triosephosphate isomerase (TIM) from unfolded monomers induced by guanidine hydrochloride involves different amino acids of its sequence in different stages of protein refolding. We describe a systematic mutagenesis method to find critical residues for certain physico-chemical properties of a protein. The two similar TIMs of Trypanosoma brucei and Trypanosoma cruzi have different reactivation velocities and efficiencies. We used a small number of chimeric enzymes, additive mutants and planned site-directed mutants to produce an enzyme from T. brucei with 13 mutations in its sequence, which reactivates fast and efficiently like wild-type (WT) TIM from T. cruzi, and another enzyme from T. cruzi, with 13 slightly altered mutations, which reactivated slowly and inefficiently like the WT TIM of T. brucei. Our method is a shorter alternative to random mutagenesis, saturation mutagenesis or directed evolution to find multiple amino acids critical for certain properties of proteins. PMID:27733588

Proteomic analysis of UVB-induced protein expression- and redox-dependent changes in skin fibroblasts using lysine- and cysteine-labeling two-dimensional difference gel electrophoresis.

PubMed

Wu, Chieh-Lin; Chou, Hsiu-Chuan; Cheng, Chao-Sheng; Li, Ji-Min; Lin, Szu-Ting; Chen, Yi-Wen; Chan, Hong-Lin

2012-04-03

UVB is the most energetic and DNA-damaging to humans in ultraviolet radiation. Previous research has suggested that exposure to UVB causes skin pathologies because of direct DNA damage and the generation of reactive oxygen species (ROS). However, the detailed molecular mechanisms by which UVB leads to skin cancer have yet to be clarified. In the current study, normal skin fibroblast cells (CCD-966SK) were exposed to various doses of UVB, and the changes in protein expression and thiol reactivity were monitored with lysine- and cysteine-labeling 2D-DIGE and MALDI-TOF mass spectrometry. Our proteomic analysis revealed that 89 identified proteins showed significant changes in protein expression, and 37 in thiol reactivity. Many proteins that are known to be involved in protein folding, redox regulation and nucleotide biosynthesis were up-regulated under UVB irradiation. In contrast, proteins responsible for biosynthesis and protein degradation were down-regulated. In addition, the thiol-reactivity of proteins involving cytoskeleton, metabolism, and signal transduction were altered by UVB. In summary, these UVB-modulated cellular proteins and redox-regulated proteins might play important roles in the early stages of skin cancer formation and photoaging induced by UVB-irradiation. Such proteins might provide a potential target for the rational design of drugs to prevent UVB-induced diseases. Copyright © 2011 Elsevier B.V. All rights reserved.

Endogenous Memory CD8 T Cells Directly Mediate Cardiac Allograft Rejection

PubMed Central

Su, C. A.; Iida, S.; Abe, T.; Fairchild, R. L.

2014-01-01

Differences in levels of environmentally induced memory T cells that cross-react with donor MHC molecules are postulated to account for the efficacy of allograft tolerance inducing strategies in rodents versus their failure in nonhuman primates and human transplant patients. Strategies to study the impact of donor-reactive memory T cells on allografts in rodents have relied on the pre-transplant induction of memory T cells cross-reactive with donor allogeneic MHC molecules through recipient viral infection, priming directly with donor antigen, or adoptive transfer of donor-antigen primed memory T cells. Each approach accelerates allograft rejection and confers resistance to tolerance induction, but also biases the T cell repertoire to strong donor-reactivity. The ability of endogenous memory T cells within unprimed mice to directly reject an allograft is unknown. Here we show a direct association between increased duration of cold ischemic allograft storage and numbers and enhanced functions of early graft infiltrating endogenous CD8 memory T cells. These T cells directly mediate rejection of allografts subjected to prolonged ischemia and this rejection is resistant to costimulatory blockade. These findings recapitulate the clinically significant impact of endogenous memory T cells with donor reactivity in a mouse transplant model in the absence of prior recipient priming. PMID:24502272

Heart rate reactivity and current post-traumatic stress disorder when data are missing.

PubMed

Jeon-Slaughter, Haekyung; Tucker, Phebe; Pfefferbaum, Betty; North, Carol S; de Andrade, Bernardo Borba; Neas, Barbara

2011-08-01

This study demonstrates that auxiliary and exclusion criteria variables increase the effectiveness of missing imputation in correcting underestimation of physiologic reactivity in relation to post-traumatic stress disorder (PTSD) caused by deleting cases with missing physiologic data. This study used data from survivors of the 1995 Oklahoma City bombing and imputed missing heart rate data using auxiliary and exclusion criteria variables. Logistic regression was used to examine heart rate reactivity in relation to current PTSD. Of 113 survivors who participated in the bombing study's 7-year follow-up interview, 42 (37%) had missing data on heart rate reactivity due to exclusion criteria (medical illness or use of cardiovascular or psychotropic medications) or non-participation. Logistic regression results based on imputed heart rate data using exclusion criteria and auxiliary (the presence of any current PTSD arousal symptoms) variables showed that survivors with current bombing-related PTSD had significantly higher heart rates at baseline and recovered more slowly back to baseline heart rate during resting periods than survivors without current PTSD, while results based on complete cases failed to show significant correlations between current PTSD and heart rates at any assessment points. Suggested methods yielded an otherwise undetectable link between physiology and current PTSD. © 2011 The Authors. Psychiatry and Clinical Neurosciences © 2011 Japanese Society of Psychiatry and Neurology.

Functional significance of men's testosterone reactivity to social stimuli.

PubMed

Zilioli, Samuele; Bird, Brian M

2017-10-01

Rapid testosterone fluctuations in response to social stimuli are observed across a wide range of species, and the highly conserved nature of these fluctuations suggests an adaptive function. This paper reviews the current literature on testosterone reactivity, primarily in human males, and illustrates how life-history theory provides an adequate theoretical framework to interpret findings. The review is structured around supporting evidence suggesting that situations implicated in mating effort either directly (e.g., interactions with a mate) or indirectly (e.g., intrasexual competition) are generally associated with a brief elevation of testosterone, while situations implicated in parenting effort (e.g., nurturant interactions with offspring) are generally associated with a decline in testosterone. Further, we discuss how these fluctuations in testosterone have been linked to future behaviors, and how situational, motivational, and physiological variables moderate the interplay between social stimuli, testosterone reactivity, and behavior. Supporting the notion that testosterone can play a causal role in modulating behavior in response to social stimuli, we also summarize recent single administration studies examining the effects of testosterone on physiology, neurobiology, and behavior. A conceptual model provides links between supported findings, and hypothesized pathways requiring future testing. Copyright © 2017 Elsevier Inc. All rights reserved.

Accelerated Weathering of Waste Glass at 90°C with the Pressurized Unsaturated Flow (PUF) Apparatus: Implications for Predicting Glass Corrosion with a Reactive Transport Model

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

Pierce, Eric M.; Bacon, Diana H.

2009-09-21

The interest in the long-term durability of waste glass stems from the need to predict radionuclide release rates from the corroding glass over geologic time-scales. Several long-term test methods have been developed to accelerate the glass-water reaction [drip test, vapor hydration test, product consistency test-B, and pressurized unsaturated flow (PUF)]. Currently, the PUF test is the only method that can mimic the unsaturated hydraulic properties expected in a subsurface disposal facility and simultaneously monitor the glass-water reaction. PUF tests are being conducted to accelerate the weathering of glass and validate the model parameters being used to predict long-term glass behavior.more » One dimensional reactive chemical transport simulations of glass dissolution and secondary phase formation during a 1.5-year long PUF experiment was conducted with the subsurface transport over reactive multi-phases (STORM) code. Results show that parameterization of the computer model by combining direct laboratory measurements and thermodynamic data provides an integrated approach to predicting glass behavior over geologic-time scales.« less

Associations between narcissism and emotion regulation difficulties: Respiratory sinus arrhythmia reactivity as a moderator.

PubMed

Zhang, Hui; Wang, Zhenhong; You, Xuqun; Lü, Wei; Luo, Yun

2015-09-01

The aim of the current study was to examine the direct and interactive effects of two types of narcissism (overt and covert) and respiratory sinus arrhythmia (RSA) reactivity on emotion regulation difficulties in 227 undergraduate students. Overt and covert narcissism and emotion regulation difficulties were assessed with self-report measures (narcissistic personality inventory (NPI)-16, hypersensitive narcissism scale (HSNS), and difficulties in emotion regulation scale (DERS)), and physiological data were measured during the baseline, stress (a public-speaking task), and recovery periods in the laboratory. Results indicated that overt narcissism was negatively related to a lack of emotional awareness and emotional clarity, whereas covert narcissism was positively related to overall emotion regulation difficulties, nonacceptance of emotional responses, impulse control difficulties, limited access to emotion regulation strategies, and a lack of emotional clarity. RSA reactivity in response to a mock job interview moderated the associations between covert narcissism (as a predictor) and overall emotion regulation difficulties and impulse control difficulties (as outcomes). This finding showed that a greater stress-induced RSA decrease may serve as a protective factor and ameliorate the effect of covert narcissism on individuals' emotion regulation difficulties. Copyright © 2015 Elsevier B.V. All rights reserved.

Modeling reactive nitrogen in North America: recent developments, observational needs and future directions

EPA Science Inventory

Nitrogen is an essential building block of all proteins and thus an essential nutrient for all life. The bulk of nitrogen in the environment is tightly bound as non-reactive N₂. Reactive nitrogen, which is naturally produced via enzymatic reactions, forest ...

Modeling and testing of reactive contaminant transport in drinking water pipes: Chlorine response and implications for online contaminant detection

EPA Science Inventory

Reactive contaminants introduced to chlorinated drinking water can cause water quality change directly related to their reactivity and other physiochemical properties. This general principle is further developed and utilized in a proposed real-time event adaptive detection, iden...

Sensitivity-Based VOC Reactivity Calculation

EPA Science Inventory

Volatile Organic Compound (VOC) reactivity scales are used to compare the ozone-forming potentials of various compounds. The comparison allows for substitution of compounds to lessen formation of ozone from paints, solvents, and other products. Current reactivity scales for VOC c...

Unexpected cross-reactivity of anti-cathepsin B antibodies leads to uncertainties regarding the mechanism of action of anti-CD20 monoclonal antibody GA101.

PubMed

Chien, Wei Wen; Niogret, Charlène; Jugé, Romain; Lionnard, Loïc; Cornut-Thibaut, Aurélie; Kucharczak, Jérôme; Savina, Ariel; Salles, Gilles; Aouacheria, Abdel

2017-04-01

GA101, also known as obinutuzumab or Gazyva (Gazyvaro), is a glycoengineered type II humanized antibody that targets the CD20 antigen expressed at the surface of B-cells. This novel anti-CD20 antibody is currently assessed in clinical trials with promising results as a single agent or as part of therapeutic combinations for the treatment of B-cell malignancies. Detailed understanding of the mechanisms of GA101-induced cell death is needed to get insight into possible resistance mechanisms occurring in patients. Although multiple in vitro and in vivo mechanisms have been suggested to describe the effects of GA101 on B-cells, currently available data are ambiguous. The aim of our study was to clarify the cellular mechanisms involved in GA101-induced cell death in vitro, and more particularly the respective roles played by lysosomal and mitochondrial membrane permeabilization. Our results confirm previous reports suggesting that GA101 triggers homotypic adhesion and caspase-independent cell death, two processes that are dependent on actin remodeling and involve the production of reactive oxygen species. With respect to lysosomal membrane permeabilization (LMP), our data suggest that lack of specificity of available antibodies directed against cathepsin B may have confounded previously published results, possibly challenging current LMP-driven model of GA101 action mode. Copyright © 2017 Elsevier Ltd. All rights reserved.

High throughput assay for evaluation of reactive carbonyl scavenging capacity.

PubMed

Vidal, N; Cavaille, J P; Graziani, F; Robin, M; Ouari, O; Pietri, S; Stocker, P

2014-01-01

Many carbonyl species from either lipid peroxidation or glycoxidation are extremely reactive and can disrupt the function of proteins and enzymes. 4-hydroxynonenal and methylglyoxal are the most abundant and toxic lipid-derived reactive carbonyl species. The presence of these toxics leads to carbonyl stress and cause a significant amount of macromolecular damages in several diseases. Much evidence indicates trapping of reactive carbonyl intermediates may be a useful strategy for inhibiting or decreasing carbonyl stress-associated pathologies. There is no rapid and convenient analytical method available for the assessment of direct carbonyl scavenging capacity, and a very limited number of carbonyl scavengers have been identified to date, their therapeutic potential being highlighted only recently. In this context, we have developed a new and rapid sensitive fluorimetric method for the assessment of reactive carbonyl scavengers without involvement glycoxidation systems. Efficacy of various thiol- and non-thiol-carbonyl scavenger pharmacophores was tested both using this screening assay adapted to 96-well microplates and in cultured cells. The scavenging effects on the formation of Advanced Glycation End-product of Bovine Serum Albumin formed with methylglyoxal, 4-hydroxynonenal and glucose-glycated as molecular models were also examined. Low molecular mass thiols with an α-amino-β-mercaptoethane structure showed the highest degree of inhibitory activity toward both α,β-unsaturated aldehydes and dicarbonyls. Cysteine and cysteamine have the best scavenging ability toward methylglyoxal. WR-1065 which is currently approved for clinical use as a protective agent against radiation and renal toxicity was identified as the best inhibitor of 4-hydroxynonenal.

Differentiating Challenge Reactivity from Psychomotor Activity in Studies of Children's Psychophysiology: Considerations for Theory and Measurement

ERIC Educational Resources Information Center

Bush, Nicole R.; Alkon, Abbey; Obradovic, Jelena; Stamperdahl, Juliet; Boyce, W. Thomas

2011-01-01

Current methods of assessing children's physiological "stress reactivity" may be confounded by psychomotor activity, biasing estimates of the relation between reactivity and health. We examined the joint and independent contributions of psychomotor activity and challenge reactivity during a protocol for 5- and 6-year-old children (N = 338).…

Paving the Way Towards Reactive Planar Spanner Construction in Wireless Networks

NASA Astrophysics Data System (ADS)

Frey, Hannes; Rührup, Stefan

A spanner is a subgraph of a given graph that supports the original graph's shortest path lengths up to a constant factor. Planar spanners and their distributed construction are of particular interest for geographic routing, which is an efficient localized routing scheme for wireless ad hoc and sensor networks. Planarity of the network graph is a key criterion for guaranteed delivery, while the spanner property supports efficiency in terms of path length. We consider the problem of reactive local spanner construction, where a node's local topology is determined on demand. Known message-efficient reactive planarization algorithms do not preserve the spanner property, while reactive spanner constructions with a low message overhead have not been described so far. We introduce the concept of direct planarization which may be an enabler of efficient reactive spanner construction. Given an edge, nodes check for all incident intersecting edges a certain geometric criterion and withdraw the edge if this criterion is not satisfied. We use this concept to derive a generic reactive topology control mechanism and consider two geometric criteria. Simulation results show that direct planarization increases the performance of localized geographic routing by providing shorter paths than existing reactive approaches.

Mapping PAM4 (clivatuzumab), a monoclonal antibody in clinical trials for early detection and therapy of pancreatic ductal adenocarcinoma, to MUC5AC mucin.

PubMed

Gold, David V; Newsome, Guy; Liu, Donglin; Goldenberg, David M

2013-11-20

PAM4, an antibody that has high specificity for pancreatic ductal adenocarcinoma (PDAC), compared to normal pancreas, benign lesions of the pancreas, and cancers originating from other tissues, is being investigated as a biomarker for early detection, as well as antibody-targeted imaging and therapy. Therefore, the identity of the antigen bound by this monoclonal antibody (MAb) can provide information leading to improved use of the antibody. Prior results suggested the antigen is a mucin-type glycoprotein rich in cysteine disulfide bridges that provide stable conformation for the PAM4-epitope. Indirect and sandwich enzyme immunoassays (EIA) were performed to compare and contrast the reactivity of PAM4 with several anti-mucin antibodies having known reactivity to specific mucin species (e.g., MUC1, MUC4, MUC5AC, etc.). Studies designed to block reactivity of PAM4 with its specific antigen also were performed. We demonstrate that MAbs 2-11 M1 and 45 M1, each reactive with MUC5AC, are able to provide signal in a heterologous sandwich immunoassay where PAM4 is the capture antibody. Further, we identify MAbs 21 M1, 62 M1, and 463 M1, each reactive with MUC5AC, as inhibiting the reaction of PAM4 with its specific epitope. MAbs directed to MUC1, MUC3, MUC4, MUC16 and CEACAM6 are not reactive with PAM4-captured antigen, nor are they able to block the reaction of PAM4 with its antigen. These data implicate MUC5AC as a specific mucin species to which PAM4 is reactive. Furthermore, this realization may allow for the improvement of the current PAM4 serum-based immunoassay for detection of early-stage PDAC by the application of anti-MUC5AC MAbs as probes in this sandwich EIA.

New Directions in Measuring Reactive and Proactive Aggression: Validation of a Teacher Questionnaire

ERIC Educational Resources Information Center

Polman, Hanneke; de Castro, Bram Orobio; Thomaes, Sander; van Aken, Marcel

2009-01-01

The well-known distinction between reactive and proactive aggression is theoretically important but empirically controversial. Recently, aggression researchers have argued that we should separate the form and function of aggression to make a clearer distinction between reactive and proactive aggression. This article describes the validation of a…

"Reactivity to Stimuli” Is a Temperamental Factor Contributing to Canine Aggression

PubMed Central

Arata, Sayaka; Takeuchi, Yukari; Inoue, Mai; Mori, Yuji

2014-01-01

Canine aggression is one of the most frequent problems in veterinary behavioral medicine, which in severe cases may result in relinquishment or euthanasia. As it is important to reveal underlying factors of aggression for both treatment and prevention, we recently developed a questionnaire on aggression and temperamental traits and found that “reactivity to stimuli” was associated with aggression toward owners, children, strangers, and other dogs of the Shiba Inu breed. In order to examine whether these associations were consistent in other breeds, we asked the owners of insured dogs of Anicom Insurance Inc. to complete our questionnaire. The top 17 contracted breeds were included. The questionnaire consisted of dogs' general information, four items related to aggression toward owners, children, strangers, and other dogs, and 20 other behavioral items. Aggression-related and behavioral items were rated on a five-point frequency scale. Valid responses (n = 5610) from owners of dogs aged 1 through 10 years were collected. Factor analyses on 18 behavioral items (response rate over 95%) extracted five largely consistent factors in 14 breeds: “sociability with humans,” “fear of sounds,” “chase proneness,” “reactivity to stimuli,” and “avoidance of aversive events.” By stepwise multiple regression analyses, using the Schwartz's Bayesian information criterion (BIC) method with aggression points as objective variables and general information and temperamental factor points as explanatory variables, “reactivity to stimuli,” i.e., physical reactivity to sudden movement or sound at home, was shown to be significantly associated with owner-directed aggression in 13 breeds, child-directed aggression in eight breeds, stranger-directed aggression in nine breeds, and dog-directed aggression in five breeds. These results suggest that “reactivity to stimuli” is simultaneously involved in several types of aggression. Therefore, it would be worth taking “reactivity to stimuli” into account in the treatment and prevention of canine aggression. PMID:24972077

A fluorescence high throughput screening method for the detection of reactive electrophiles as potential skin sensitizers.

PubMed

Avonto, Cristina; Chittiboyina, Amar G; Rua, Diego; Khan, Ikhlas A

2015-12-01

Skin sensitization is an important toxicological end-point in the risk assessment of chemical allergens. Because of the complexity of the biological mechanisms associated with skin sensitization, integrated approaches combining different chemical, biological and in silico methods are recommended to replace conventional animal tests. Chemical methods are intended to characterize the potential of a sensitizer to induce earlier molecular initiating events. The presence of an electrophilic mechanistic domain is considered one of the essential chemical features to covalently bind to the biological target and induce further haptenation processes. Current in chemico assays rely on the quantification of unreacted model nucleophiles after incubation with the candidate sensitizer. In the current study, a new fluorescence-based method, 'HTS-DCYA assay', is proposed. The assay aims at the identification of reactive electrophiles based on their chemical reactivity toward a model fluorescent thiol. The reaction workflow enabled the development of a High Throughput Screening (HTS) method to directly quantify the reaction adducts. The reaction conditions have been optimized to minimize solubility issues, oxidative side reactions and increase the throughput of the assay while minimizing the reaction time, which are common issues with existing methods. Thirty-six chemicals previously classified with LLNA, DPRA or KeratinoSens™ were tested as a proof of concept. Preliminary results gave an estimated 82% accuracy, 78% sensitivity, 90% specificity, comparable to other in chemico methods such as Cys-DPRA. In addition to validated chemicals, six natural products were analyzed and a prediction of their sensitization potential is presented for the first time. Copyright © 2015 Elsevier Inc. All rights reserved.

Understanding the Reactivity of Lunar Dust for Future Lunar Missions

NASA Technical Reports Server (NTRS)

Wallace, W. T.; Jeevarajan, A. S.; Taylor, L. A.

2010-01-01

Fluorescence and EPR can be used to measure the reactivity of lunar soil. Lunar soil is highly activated by grinding. Reactivity is dependent upon soil maturity and locale. Maturity is based on the amount of nanophase iron (np-Fe) in a soil relative to the total iron (FeO). Lunar soil activity ia a direct function of the amount of np-Fe present. Reactive soil can be "deactivated" by humid atmosphere.

Cue-reactivity in behavioral addictions: A meta-analysis and methodological considerations.

PubMed

Starcke, Katrin; Antons, Stephanie; Trotzke, Patrick; Brand, Matthias

2018-05-23

Background and aims Recent research has applied cue-reactivity paradigms to behavioral addictions. The aim of the current meta-analysis is to systematically analyze the effects of learning-based cue-reactivity in behavioral addictions. Methods The current meta-analysis includes 18 studies (29 data sets, 510 participants) that have used a cue-reactivity paradigm in persons with gambling (eight studies), gaming (nine studies), or buying (one study) disorders. We compared subjective, peripheral physiological, electroencephal, and neural responses toward addiction-relevant cues in patients versus control participants and toward addiction-relevant cues versus control cues in patients. Results Persons with behavioral addictions showed higher cue-reactivity toward addiction-relevant cues compared with control participants: subjective cue-reactivity (d = 0.84, p = .01) and peripheral physiological and electroencephal measures of cue-reactivity (d = 0.61, p < .01). Increased neural activation was found in the caudate nucleus, inferior frontal gyrus, median cingulate cortex, subgenual cingulate, and precentral gyrus. Persons with gambling, gaming, or buying disorders also showed higher cue-reactivity toward addiction-relevant cues compared with control cues: subjective cue-reactivity (d = 0.39, p = .11) and peripheral physiological and electroencephal measures of cue-reactivity (d = 0.47, p = .05). Increased neural activation was found in the caudate nucleus, inferior frontal gyrus, angular gyrus, inferior network, and precuneus. Discussion and conclusions Cue-reactivity not only exists in substance-use disorders but also in gambling, gaming, and buying disorders. Future research should differentiate between cue-reactivity in addictive behaviors and cue-reactivity in functional excessive behaviors such as passions, hobbies, or professions.

Development and application of bond cleavage reactions in bioorthogonal chemistry.

PubMed

Li, Jie; Chen, Peng R

2016-03-01

Bioorthogonal chemical reactions are a thriving area of chemical research in recent years as an unprecedented technique to dissect native biological processes through chemistry-enabled strategies. However, current concepts of bioorthogonal chemistry have largely centered on 'bond formation' reactions between two mutually reactive bioorthogonal handles. Recently, in a reverse strategy, a collection of 'bond cleavage' reactions has emerged with excellent biocompatibility. These reactions have expanded our bioorthogonal chemistry repertoire, enabling an array of exciting new biological applications that range from the chemically controlled spatial and temporal activation of intracellular proteins and small-molecule drugs to the direct manipulation of intact cells under physiological conditions. Here we highlight the development and applications of these bioorthogonal cleavage reactions. Furthermore, we lay out challenges and propose future directions along this appealing avenue of research.

Voltage control for a wind power plant based on the available reactive current of a DFIG and its impacts on the point of interconnection

DOE PAGES

Usman, Yasir; Kim, Jinho; Muljadi, Eduard; ...

2016-01-01

Wake effects cause wind turbine generators (WTGs) within a wind power plant (WPP) to produce different levels of active power and subsequent reactive power capabilities. Further, the impedance between a WTG and the point of interconnection (POI)-which depends on the distance between them-impacts the WPP's reactive power injection capability at the POI. This paper proposes a voltage control scheme for a WPP based on the available reactive current of the doubly-fed induction generators (DFIGs) and its impacts on the POI to improve the reactive power injection capability of the WPP. In this paper, a design strategy for modifying the gainmore » of DFIG controller is suggested and the comprehensive properties of these control gains are investigated. In the proposed scheme, the WPP controller, which operates in a voltage control mode, sends the command signal to the DFIGs based on the voltage difference at the POI. The DFIG controllers, which operate in a voltage control mode, employ a proportional controller with a limiter. The gain of the proportional controller is adjusted depending on the available reactive current of the DFIG and the series impedance between the DFIG and the POI. The performance of the proposed scheme is validated for various disturbances such as a reactive load connection and grid fault using an EMTP-RV simulator. Furthermore, simulation results demonstrate that the proposed scheme promptly recovers the POI voltage by injecting more reactive power after a disturbance than the conventional scheme.« less

Module Twelve: Series AC Resistive-Reactive Circuits; Basic Electricity and Electronics Individualized Learning System.

ERIC Educational Resources Information Center

Bureau of Naval Personnel, Washington, DC.

The module covers series circuits which contain both resistive and reactive components and methods of solving these circuits for current, voltage, impedance, and phase angle. The module is divided into six lessons: voltage and impedance in AC (alternating current) series circuits, vector computations, rectangular and polar notation, variational…

A Gas-Kinetic Scheme for Reactive Flows

NASA Technical Reports Server (NTRS)

Lian,Youg-Sheng; Xu, Kun

1998-01-01

In this paper, the gas-kinetic BGK scheme for the compressible flow equations is extended to chemical reactive flow. The mass fraction of the unburnt gas is implemented into the gas kinetic equation by assigning a new internal degree of freedom to the particle distribution function. The new variable can be also used to describe fluid trajectory for the nonreactive flows. Due to the gas-kinetic BGK model, the current scheme basically solves the Navier-Stokes chemical reactive flow equations. Numerical tests validate the accuracy and robustness of the current kinetic method.

Herpes Zoster reactivation in patients with chronic hepatitis C under treatment with directly acting antiviral agents: A case series.

PubMed

El Kassas, Mohamed; Wifi, Mohamed Naguib; Mahdy, Reem; Afify, Shimaa; Hafez, Enas; El Latif, Yasmeen Abd; Ezzat, Marwa; El Tahan, Adel; Youssef, Naglaa; Esmat, Gamal

2017-03-01

We report a series of cutaneous Herpes Zoster (HZ) reactivation cases in patients with hepatitis C virus (HCV) infection treated with directly acting antiviral (DAA) agents. Five cases were detected among 2133 treated patients with DAAs at one of the specialized viral hepatitis treatment centers in Egypt. A control group including 2300 age and sex matched HCV patients who were previously treated with pegylated interferon and ribavirin did not show any HZ reactivation reports while on treatment. None of cases had an evidence of immunosuppression or a risk factor for HZ reactivation. The DAAs used regimens were sofosbuvir/daclatasvir in 4 cases and sofosbuvir/simeprevir in one case. HCV clearance with antiviral therapy may bring immune changes causing reactivation of other latent viral infections like HZ. A high index of clinical suspicion may be needed to guarantee early and prompt management of such cases. Copyright © 2017 Pan-Arab Association of Gastroenterology. Published by Elsevier B.V. All rights reserved.

Modelling of the reactive sputtering process with non-uniform discharge current density and different temperature conditions

NASA Astrophysics Data System (ADS)

Vašina, P; Hytková, T; Eliáš, M

2009-05-01

The majority of current models of the reactive magnetron sputtering assume a uniform shape of the discharge current density and the same temperature near the target and the substrate. However, in the real experimental set-up, the presence of the magnetic field causes high density plasma to form in front of the cathode in the shape of a toroid. Consequently, the discharge current density is laterally non-uniform. In addition to this, the heating of the background gas by sputtered particles, which is usually referred to as the gas rarefaction, plays an important role. This paper presents an extended model of the reactive magnetron sputtering that assumes the non-uniform discharge current density and which accommodates the gas rarefaction effect. It is devoted mainly to the study of the behaviour of the reactive sputtering rather that to the prediction of the coating properties. Outputs of this model are compared with those that assume uniform discharge current density and uniform temperature profile in the deposition chamber. Particular attention is paid to the modelling of the radial variation of the target composition near transitions from the metallic to the compound mode and vice versa. A study of the target utilization in the metallic and compound mode is performed for two different discharge current density profiles corresponding to typical two pole and multipole magnetics available on the market now. Different shapes of the discharge current density were tested. Finally, hysteresis curves are plotted for various temperature conditions in the reactor.

Atmospheric pressure cold plasma as an antifungal therapy

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

Sun Peng; Wu Haiyan; Sun Yi

2011-01-10

A microhollow cathode based, direct-current, atmospheric pressure, He/O{sub 2} (2%) cold plasma microjet was used to inactive antifungal resistants Candida albicans, Candida krusei, and Candida glabrata in air and in water. Effective inactivation (>90%) was achieved in 10 min in air and 1 min in water. Antifungal susceptibility tests showed drastic reduction of the minimum inhibitory concentration after plasma treatment. The inactivation was attributed to the reactive oxygen species generated in plasma or in water. Hydroxyl and singlet molecular oxygen radicals were detected in plasma-water system by electron spin resonance spectroscopy. This approach proposed a promising clinical dermatology therapy.

Facet-dependent photocatalytic properties of TiO(2) -based composites for energy conversion and environmental remediation.

PubMed

Ong, Wee-Jun; Tan, Lling-Lling; Chai, Siang-Piao; Yong, Siek-Ting; Mohamed, Abdul Rahman

2014-03-01

Titanium dioxide (TiO2 ) is one of the most widely investigated metal oxides because of its extraordinary surface, electronic, and photocatalytic properties. However, the large band gap of TiO2 and the considerable recombination of photogenerated electron-hole pairs limit its photocatalytic efficiency. Therefore, research attention is being increasingly directed towards engineering the surface structure of TiO2 on the atomic level (namely morphological control of {001} facets on the micro- and nanoscale) to fine-tune its physicochemical properties; this could ultimately lead to the optimization of selectivity and reactivity. This Review encompasses the fundamental principles to enhance the photocatalytic activity by using highly reactive {001}-faceted TiO2 -based composites. The current progress of such composites, with particular emphasis on the photodegradation of pollutants and photocatalytic water splitting for hydrogen generation, is also discussed. The progresses made are thoroughly examined for achieving remarkable photocatalytic performances, with additional insights with regard to charge transfer. Finally, a summary and some perspectives on the challenges and new research directions for future exploitation in this emerging frontier are provided, which hopefully would allow for harnessing the outstanding structural and electronic properties of {001} facets for various energy- and environmental-related applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Role of resveratrol in regulation of cellular defense systems against oxidative stress.

PubMed

Truong, Van-Long; Jun, Mira; Jeong, Woo-Sik

2018-01-01

Resveratrol, a natural polyphenolic compound, is found in various kinds of fruits, plants, and their commercial products such as red wine. It has been demonstrated to exhibit a variety of health-promoting effects including prevention and/or treatment of cardiovascular diseases, inflammation, diabetes, neurodegeneration, aging, and cancer. Cellular defensive properties of resveratrol can be explained through its ability of either directly neutralizing reactive oxygen species/reactive nitrogen species (ROS/RNS) or indirectly upregulating the expression of cellular defensive genes. As a direct antioxidant agent, resveratrol scavenges diverse ROS/RNS as well as secondary organic radicals with mechanisms of hydrogen atom transfer and sequential proton loss electron transfer, thereby protecting cellular biomolecules from oxidative damage. Resveratrol also enhances the expression of various antioxidant defensive enzymes such as heme oxygenase 1, catalase, glutathione peroxidase, and superoxide dismutase as well as the induction of glutathione level responsible for maintaining the cellular redox balance. Such defenses could be achieved by regulating various signaling pathways including sirtuin 1, nuclear factor-erythroid 2-related factor 2 and nuclear factor κB. This review provides current understanding and information on the role of resveratrol in cellular defense system against oxidative stress. © 2017 BioFactors, 44(1):36-49, 2018. © 2017 International Union of Biochemistry and Molecular Biology.

Electric-Field-Oriented Growth of Long Hair-Like Silica Microfibrils and Derived Functional Monolithic Solids

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

Hu, Michael Z.; DePaoli, David W.; Kuritz, Tanya

We present a “bottom-up” fabrication approach to first grow a new class of inorganic (silica) long hair-like microfibers or microwires and then to form monolithic solid pellet that contains parallel arrays of bundled microfibers with a controlled orientation. During the sol-gel solution processing, reactive precursor species are utilized as molecular “building blocks” for the field-directed assembly growth of microfibers driven by an electric field of pulsed direct current (dc) with controlled frequency. In principle, this reactive electrofibrilation process that combines an external field with a solid-phase nucleation and growth process has no limitation on reactions (such as the one heremore » that involves sol-gel reaction chemistry) and on materials compositions (such as the example silica oxide), thus will enable bulk production of long microfibers of wide variety of inorganic materials (other oxides or metals). Furthermore, we have fabricated uniquely architectured monolithic solid materials containing aligned microfibers by “wet press” of the in-situ grown microfiber structure in the electric field. The consolidated monolithic slabs (1 cm x 1 cm x 3 mm) have shown anisotropic properties and desirable retention of DNA molecule fragments, thus, could serve as a platform stationary-phase materials for future development of capillary electrochromatography for biomolecule separations.« less

Electric-Field-Oriented Growth of Long Hair-Like Silica Microfibrils and Derived Functional Monolithic Solids

DOE PAGES

Hu, Michael Z.; DePaoli, David W.; Kuritz, Tanya; ...

2017-09-11

We present a “bottom-up” fabrication approach to first grow a new class of inorganic (silica) long hair-like microfibers or microwires and then to form monolithic solid pellet that contains parallel arrays of bundled microfibers with a controlled orientation. During the sol-gel solution processing, reactive precursor species are utilized as molecular “building blocks” for the field-directed assembly growth of microfibers driven by an electric field of pulsed direct current (dc) with controlled frequency. In principle, this reactive electrofibrilation process that combines an external field with a solid-phase nucleation and growth process has no limitation on reactions (such as the one heremore » that involves sol-gel reaction chemistry) and on materials compositions (such as the example silica oxide), thus will enable bulk production of long microfibers of wide variety of inorganic materials (other oxides or metals). Furthermore, we have fabricated uniquely architectured monolithic solid materials containing aligned microfibers by “wet press” of the in-situ grown microfiber structure in the electric field. The consolidated monolithic slabs (1 cm x 1 cm x 3 mm) have shown anisotropic properties and desirable retention of DNA molecule fragments, thus, could serve as a platform stationary-phase materials for future development of capillary electrochromatography for biomolecule separations.« less

Human T-cells directed to seasonal influenza A virus cross-react with 2009 pandemic influenza A (H1N1) and swine-origin triple-reassortant H3N2 influenza viruses.

PubMed

Hillaire, Marine L B; Vogelzang-van Trierum, Stella E; Kreijtz, Joost H C M; de Mutsert, Gerrie; Fouchier, Ron A M; Osterhaus, Albert D M E; Rimmelzwaan, Guus F

2013-03-01

Virus-specific CD8(+) T-cells contribute to protective immunity against influenza A virus (IAV) infections. As the majority of these cells are directed to conserved viral proteins, they may afford protection against IAVs of various subtypes. The present study assessed the cross-reactivity of human CD8(+) T-lymphocytes, induced by infection with seasonal A (H1N1) or A (H3N2) influenza virus, with 2009 pandemic influenza A (H1N1) virus [A(H1N1)pdm09] and swine-origin triple-reassortant A (H3N2) [A(H3N2)v] viruses that are currently causing an increasing number of human cases in the USA. It was demonstrated that CD8(+) T-cells induced after seasonal IAV infections exerted lytic activity and produced gamma interferon upon in vitro restimulation with A(H1N1)pdm09 and A(H3N2)v influenza A viruses. Furthermore, CD8(+) T-cells directed to A(H1N1)pdm09 virus displayed a high degree of cross-reactivity with A(H3N2)v viruses. It was concluded that cross-reacting T-cells had the potential to afford protective immunity against A(H1N1)pdm09 viruses during the pandemic and offer some degree of protection against infection with A(H3N2)v viruses.

Stability and reactivity of dimethylethoxysilane

NASA Technical Reports Server (NTRS)

Johnson, Richard E.; Ford, Douglas I.

1992-01-01

Dimethylethoxysilane (DMES) is currently used to treat the High-temperature Reusable Surface Insulation (HRSI) shuttle tiles in order to provide a hydrophobic surface on the silica. DMES is a volatile, reactive silane that incorporates two reactive sites, the ethoxy group and the silica-hydride group. The work reported in this paper focused on the reactivity of these two groups with silica, water, quantitative reagents, and within DMES itself.

High precision during food recruitment of experienced (reactivated) foragers in the stingless bee Scaptotrigona mexicana (Apidae, Meliponini)

NASA Astrophysics Data System (ADS)

Sánchez, Daniel; Nieh, James C.; Hénaut, Yann; Cruz, Leopoldo; Vandame, Rémy

Several studies have examined the existence of recruitment communication mechanisms in stingless bees. However, the spatial accuracy of location-specific recruitment has not been examined. Moreover, the location-specific recruitment of reactivated foragers, i.e., foragers that have previously experienced the same food source at a different location and time, has not been explicitly examined. However, such foragers may also play a significant role in colony foraging, particularly in small colonies. Here we report that reactivated Scaptotrigona mexicana foragers can recruit with high precision to a specific food location. The recruitment precision of reactivated foragers was evaluated by placing control feeders to the left and the right of the training feeder (direction-precision tests) and between the nest and the training feeder and beyond it (distance-precision tests). Reactivated foragers arrived at the correct location with high precision: 98.44% arrived at the training feeder in the direction trials (five-feeder fan-shaped array, accuracy of at least +/-6° of azimuth at 50 m from the nest), and 88.62% arrived at the training feeder in the distance trials (five-feeder linear array, accuracy of at least +/-5 m or +/-10% at 50 m from the nest). Thus, S. mexicana reactivated foragers can find the indicated food source at a specific distance and direction with high precision, higher than that shown by honeybees, Apis mellifera, which do not communicate food location at such close distances to the nest.

A Primer on Observational Measurement.

PubMed

Girard, Jeffrey M; Cohn, Jeffrey F

2016-08-01

Observational measurement plays an integral role in a variety of scientific endeavors within biology, psychology, sociology, education, medicine, and marketing. The current article provides an interdisciplinary primer on observational measurement; in particular, it highlights recent advances in observational methodology and the challenges that accompany such growth. First, we detail the various types of instrument that can be used to standardize measurements across observers. Second, we argue for the importance of validity in observational measurement and provide several approaches to validation based on contemporary validity theory. Third, we outline the challenges currently faced by observational researchers pertaining to measurement drift, observer reactivity, reliability analysis, and time/expense. Fourth, we describe recent advances in computer-assisted measurement, fully automated measurement, and statistical data analysis. Finally, we identify several key directions for future observational research to explore.

Interrogating heterobimetallic co-catalytic responses for the electrocatalytic reduction of CO2 using supramolecular assembly.

PubMed

Machan, Charles W; Kubiak, Clifford P

2016-10-12

The use of hydrogen-bonding interactions to direct the non-covalent assembly of a heterobimetallic supramolecular system with Re and Mn bipyridine-based electrocatalysts is reported. Under catalytic conditions, the formation of hydrogen bonds generates a catalyst system which passes ∼10% more current than the individual current responses of the respective Re and Mn complexes for the reduction of CO 2 to CO and H 2 O. Infrared spectroelectrochemical studies indicate that the Re and Mn metal centers interact during the reduction mechanism, even forming heterobimetallic bonds under reducing conditions in the absence of substrate. These findings demonstrate that non-covalent assembly is a powerful method for generating new co-catalyst systems with greater reactivity and efficiency for transformations of interest.

GREEN CHEMISTRY. Shape-selective zeolite catalysis for bioplastics production.

PubMed

Dusselier, Michiel; Van Wouwe, Pieter; Dewaele, Annelies; Jacobs, Pierre A; Sels, Bert F

2015-07-03

Biodegradable and renewable polymers, such as polylactic acid, are benign alternatives for petrochemical-based plastics. Current production of polylactic acid via its key building block lactide, the cyclic dimer of lactic acid, is inefficient in terms of energy, time, and feedstock use. We present a direct zeolite-based catalytic process, which converts lactic acid into lactide. The shape-selective properties of zeolites are essential to attain record lactide yields, outperforming those of the current multistep process by avoiding both racemization and side-product formation. The highly productive process is strengthened by facile recovery and practical reactivation of the catalyst, which remains structurally fit during at least six consecutive reactions, and by the ease of solvent and side-product recycling. Copyright © 2015, American Association for the Advancement of Science.

Dual Priming Oligonucleotides for Broad-Range Amplification of the Bacterial 16S rRNA Gene Directly from Human Clinical Specimens

PubMed Central

Simmon, Keith; Karaca, Dilek; Langeland, Nina; Wiker, Harald G.

2012-01-01

Broad-range amplification and sequencing of the bacterial 16S rRNA gene directly from clinical specimens are offered as a diagnostic service in many laboratories. One major pitfall is primer cross-reactivity with human DNA which will result in mixed chromatograms. Mixed chromatograms will complicate subsequent sequence analysis and impede identification. In SYBR green real-time PCR assays, it can also affect crossing threshold values and consequently the status of a specimen as positive or negative. We evaluated two conventional primer pairs in common use and a new primer pair based on the dual priming oligonucleotide (DPO) principle. Cross-reactivity was observed when both conventional primer pairs were used, resulting in interpretation difficulties. No cross-reactivity was observed using the DPOs even in specimens with a high ratio of human to bacterial DNA. In addition to reducing cross-reactivity, the DPO principle also offers a high degree of flexibility in the design of primers and should be considered for any PCR assay intended for detection and identification of pathogens directly from human clinical specimens. PMID:22278843

Direct measurement of NO3 radical reactivity in a boreal forest

NASA Astrophysics Data System (ADS)

Liebmann, Jonathan; Karu, Einar; Sobanski, Nicolas; Schuladen, Jan; Ehn, Mikael; Schallhart, Simon; Quéléver, Lauriane; Hellen, Heidi; Hakola, Hannele; Hoffmann, Thorsten; Williams, Jonathan; Fischer, Horst; Lelieveld, Jos; Crowley, John N.

2018-03-01

We present the first direct measurements of NO3 reactivity (or inverse lifetime, s-1) in the Finnish boreal forest. The data were obtained during the IBAIRN campaign (Influence of Biosphere-Atmosphere Interactions on the Reactive Nitrogen budget) which took place in Hyytiälä, Finland during the summer/autumn transition in September 2016. The NO3 reactivity was generally very high with a maximum value of 0.94 s-1 and displayed a strong diel variation with a campaign-averaged nighttime mean value of 0.11 s-1 compared to a daytime value of 0.04 s-1. The highest nighttime NO3 reactivity was accompanied by major depletion of canopy level ozone and was associated with strong temperature inversions and high levels of monoterpenes. The daytime reactivity was sufficiently large that reactions of NO3 with organic trace gases could compete with photolysis and reaction with NO. There was no significant reduction in the measured NO3 reactivity between the beginning and end of the campaign, indicating that any seasonal reduction in canopy emissions of reactive biogenic trace gases was offset by emissions from the forest floor. Observations of biogenic hydrocarbons (BVOCs) suggested a dominant role for monoterpenes in determining the NO3 reactivity. Reactivity not accounted for by in situ measurement of NO and BVOCs was variable across the diel cycle with, on average, ≈ 30 % missing during nighttime and ≈ 60 % missing during the day. Measurement of the NO3 reactivity at various heights (8.5 to 25 m) both above and below the canopy, revealed a strong nighttime, vertical gradient with maximum values closest to the ground. The gradient disappeared during the daytime due to efficient vertical mixing.

Evaluation of the effect of elastic joints on the auto-oscillation of spacecraft with gas-reactive direction systems

NASA Technical Reports Server (NTRS)

Sasin, G. G.

1979-01-01

A mathematical model was obtained, on the basis of the method of mixed coordinates, of a generalized flexible spacecraft at one end of which was appended the directive action of a system of gas reactive nozzles. Various structural forms were obtained functionally describing flexible spacecraft, as systems consisting of a solid central body with flexible structural elements joined to it.

Mediating the distal crime-drug relationship with proximal reactive criminal thinking.

PubMed

Walters, Glenn D

2016-02-01

This article describes the results of a study designed to test whether reactive criminal thinking (RCT) does a better job of mediating the crime → drug relationship than it does mediating the drug → crime relationship after the direct effects of crime on drug use/dependency and of drug use/dependency on crime have been rendered nonsignificant by control variables. All 1,170 male members of the Pathways to Desistance study (Mulvey, 2012) served as participants in the current investigation. As predicted, the total (unmediated) effects of crime on substance use/dependence and of substance use/dependence on crime were nonsignificant when key demographic and third variables were controlled, although the indirect (RCT-mediated) effect of crime on drug use was significant. Proactive criminal thinking (PCT), by comparison, failed to mediate either relationship. The RCT continued to mediate the crime → drug relationship and the PCT continued to not mediate either relationship when more specific forms of offending (aggressive, income) and substance use/dependence (drug use, substance-use dependency symptoms) were analyzed. This offers preliminary support for the notion that even when the total crime-drug effect is nonsignificant the indirect path from crime to reactive criminal thinking to drugs can still be significant. Based on these results, it is concluded that mediation by proximal reactive criminal thinking is a mechanism by which distal measures of crime and drug use/dependence are connected. (c) 2016 APA, all rights reserved).

Inflammation, cancer, and targets of ginseng.

PubMed

Hofseth, Lorne J; Wargovich, Michael J

2007-01-01

Chronic inflammation is associated with a high cancer risk. At the molecular level, free radicals and aldehydes, produced during chronic inflammation, can induce deleterious gene mutation and posttranslational modifications of key cancer-related proteins. Other products of inflammation, including cytokines, growth factors, and transcription factors such as nuclear factor kappaB, control the expression of cancer genes (e.g., suppressor genes and oncogenes) and key inflammatory enzymes such as inducible nitric oxide synthase and cyclooxygenase-2. These enzymes in turn directly influence reactive oxygen species and eicosanoid levels. The procancerous outcome of chronic inflammation is increased DNA damage, increased DNA synthesis, cellular proliferation, disruption of DNA repair pathways and cellular milieu, inhibition of apoptosis, and promotion of angiogenesis and invasion. Chronic inflammation is also associated with immunosuppression, which is a risk factor for cancer. Current treatment strategies for reactive species overload diseases are frequently aimed at treating or preventing the cause of inflammation. Although these strategies have led to some progress in combating reactive species overload diseases and associated cancers, exposure often occurs again after eradication, treatment to eradicate the cause fails, or the treatment has long-term side effects. Therefore, the identification of molecules and pathways involved in chronic inflammation and cancer is critical to the design of agents that may help in preventing the progression of reactive species overload disease and cancer associated with disease progression. Here, we use ginseng as an example of an antiinflammatory molecule that targets many of the key players in the inflammation-to-cancer sequence.

Atmospheric-pressure plasma decontamination/sterilization chamber

DOEpatents

Herrmann, Hans W.; Selwyn, Gary S.

2001-01-01

An atmospheric-pressure plasma decontamination/sterilization chamber is described. The apparatus is useful for decontaminating sensitive equipment and materials, such as electronics, optics and national treasures, which have been contaminated with chemical and/or biological warfare agents, such as anthrax, mustard blistering agent, VX nerve gas, and the like. There is currently no acceptable procedure for decontaminating such equipment. The apparatus may also be used for sterilization in the medical and food industries. Items to be decontaminated or sterilized are supported inside the chamber. Reactive gases containing atomic and metastable oxygen species are generated by an atmospheric-pressure plasma discharge in a He/O.sub.2 mixture and directed into the region of these items resulting in chemical reaction between the reactive species and organic substances. This reaction typically kills and/or neutralizes the contamination without damaging most equipment and materials. The plasma gases are recirculated through a closed-loop system to minimize the loss of helium and the possibility of escape of aerosolized harmful substances.

Viral infections in acute graft-versus-host disease: a review of diagnostic and therapeutic approaches.

PubMed

Tong, Lana X; Worswick, Scott D

2015-04-01

While immunosuppressive therapy for acute graft-versus-host disease (aGVHD) advances, viral reactivation has been found to be an increasingly common complication in these patients. Dermatologists may often be consulted on inpatient services for evaluation. We investigated the literature for the role of viral infections in aGVHD and review the current evidence regarding management. Articles in the public domain regarding aGVHD, cytomegalovirus, Epstein-Barr virus, varicella zoster virus, hepatitis viruses, parvovirus B19, and respiratory viruses were included. Dermatologic findings vary between different viral antigens, and some infections may be a marker for the development of aGVHD or worsen prognosis. The heterogeneous cohorts of the studies reviewed often preclude direct comparison between results. The relationship between viral reactivation and aGVHD may be bidirectional and is worthy of further exploration. Additional studies are needed to determine appropriate prophylaxis and treatment. Copyright © 2014 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Cascaded H-bridge multilevel inverter for renewable energy generation

NASA Astrophysics Data System (ADS)

Pandey, Ravikant; Nath Tripathi, Ravi; Hanamoto, Tsuyoshi

2016-04-01

In this paper cascaded H-bridge multilevel inverter (CHBMLI) has been investigated for the application of renewable energy generation. Energy sources like solar, wind, hydro, biomass or combination of these can be manipulated to obtain alternative sources for renewable energy generation. These renewable energy sources have different electrical characteristics like DC or AC level so it is challenging to use generated power by connecting to grid or load directly. The renewable energy source require specific power electronics converter as an interface for conditioning generated power .The multilevel inverter can be utilized for renewable energy sources in two different modes, the power generation mode (stand-alone mode), and compensator mode (statcom). The performance of the multilevel inverter has been compared with two level inverter. In power generation mode CHBMLI supplies the active and reactive power required by the different loads. For operation in compensator mode the indirect current control based on synchronous reference frame theory (SRFT) ensures the grid operating in unity power factor and compensate harmonics and reactive power.

Deposition of highly textured AlN thin films by reactive high power impulse magnetron sputtering

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

Moreira, Milena A.; Törndahl, Tobias; Katardjiev, Ilia

2015-03-15

Aluminum nitride thin films were deposited by reactive high power impulse magnetron sputtering (HiPIMS) and pulsed direct-current on Si (100) and textured Mo substrates, where the same deposition conditions were used for both techniques. The films were characterized by x-ray diffraction and atomic force microscopy. The results show a pronounced improvement in the AlN crystalline texture for all films deposited by HiPIMS on Si. Already at room temperature, the HiPIMS films exhibited a strong preferred (002) orientation and at 400 °C, no contributions from other orientations were detected. Despite the low film thickness of only 200 nm, an ω-scan full width atmore » half maximum value of 5.1° was achieved on Si. The results are attributed to the high ionization of sputtered material achieved in HiPIMS. On textured Mo, there was no significant difference between the deposition techniques.« less

Decorative black TiCxOy film fabricated by DC magnetron sputtering without importing oxygen reactive gas

NASA Astrophysics Data System (ADS)

Ono, Katsushi; Wakabayashi, Masao; Tsukakoshi, Yukio; Abe, Yoshiyuki

2016-02-01

Decorative black TiCxOy films were fabricated by dc (direct current) magnetron sputtering without importing the oxygen reactive gas into the sputtering chamber. Using a ceramic target of titanium oxycarbide (TiC1.59O0.31), the oxygen content in the films could be easily controlled by adjustment of total sputtering gas pressure without remarkable change of the carbon content. The films deposited at 2.0 and 4.0 Pa, those are higher pressure when compared with that in conventional magnetron sputtering, showed an attractive black color. In particular, the film at 4.0 Pa had the composition of TiC1.03O1.10, exhibited the L* of 41.5, a* of 0.2 and b* of 0.6 in CIELAB color space. These values were smaller than those in the TiC0.29O1.38 films (L* of 45.8, a* of 1.2 and b* of 1.2) fabricated by conventional reactive sputtering method from the same target under the conditions of gas pressure of 0.3 Pa and optimized oxygen reactive gas concentration of 2.5 vol.% in sputtering gas. Analysis of XRD and XPS revealed that the black film deposited at 4.0 Pa was the amorphous film composed of TiC, TiO and C. The adhesion property and the heat resisting property were enough for decorative uses. This sputtering process has an industrial advantage that the decorative black coating with color uniformity in large area can be easily obtained by plain operation because of unnecessary of the oxygen reactive gas importing which is difficult to be controlled uniformly in the sputtering chamber.

Mutations in Nature Conferred a High Affinity Phosphatidylinositol 4,5-Bisphosphate-binding Site in Vertebrate Inwardly Rectifying Potassium Channels*

PubMed Central

Tang, Qiong-Yao; Larry, Trevor; Hendra, Kalen; Yamamoto, Erica; Bell, Jessica; Cui, Meng; Logothetis, Diomedes E.; Boland, Linda M.

2015-01-01

All vertebrate inwardly rectifying potassium (Kir) channels are activated by phosphatidylinositol 4,5-bisphosphate (PIP2) (Logothetis, D. E., Petrou, V. I., Zhang, M., Mahajan, R., Meng, X. Y., Adney, S. K., Cui, M., and Baki, L. (2015) Annu. Rev. Physiol. 77, 81–104; Fürst, O., Mondou, B., and D'Avanzo, N. (2014) Front. Physiol. 4, 404–404). Structural components of a PIP2-binding site are conserved in vertebrate Kir channels but not in distantly related animals such as sponges and sea anemones. To expand our understanding of the structure-function relationships of PIP2 regulation of Kir channels, we studied AqKir, which was cloned from the marine sponge Amphimedon queenslandica, an animal that represents the phylogenetically oldest metazoans. A requirement for PIP2 in the maintenance of AqKir activity was examined in intact oocytes by activation of a co-expressed voltage-sensing phosphatase, application of wortmannin (at micromolar concentrations), and activation of a co-expressed muscarinic acetylcholine receptor. All three mechanisms to reduce the availability of PIP2 resulted in inhibition of AqKir current. However, time-dependent rundown of AqKir currents in inside-out patches could not be re-activated by direct application to the inside membrane surface of water-soluble dioctanoyl PIP2, and the current was incompletely re-activated by the more hydrophobic arachidonyl stearyl PIP2. When we introduced mutations to AqKir to restore two positive charges within the vertebrate PIP2-binding site, both forms of PIP2 strongly re-activated the mutant sponge channels in inside-out patches. Molecular dynamics simulations validate the additional hydrogen bonding potential of the sponge channel mutants. Thus, nature's mutations conferred a high affinity activation of vertebrate Kir channels by PIP2, and this is a more recent evolutionary development than the structures that explain ion channel selectivity and inward rectification. PMID:25957411

Proactive and reactive control depends on emotional valence: a Stroop study with emotional expressions and words.

PubMed

Kar, Bhoomika Rastogi; Srinivasan, Narayanan; Nehabala, Yagyima; Nigam, Richa

2018-03-01

We examined proactive and reactive control effects in the context of task-relevant happy, sad, and angry facial expressions on a face-word Stroop task. Participants identified the emotion expressed by a face that contained a congruent or incongruent emotional word (happy/sad/angry). Proactive control effects were measured in terms of the reduction in Stroop interference (difference between incongruent and congruent trials) as a function of previous trial emotion and previous trial congruence. Reactive control effects were measured in terms of the reduction in Stroop interference as a function of current trial emotion and previous trial congruence. Previous trial negative emotions exert greater influence on proactive control than the positive emotion. Sad faces in the previous trial resulted in greater reduction in the Stroop interference for happy faces in the current trial. However, current trial angry faces showed stronger adaptation effects compared to happy faces. Thus, both proactive and reactive control mechanisms are dependent on emotional valence of task-relevant stimuli.

Phenotypic modulation of auto-reactive cells by insertion of tolerogenic molecules via MSC-derived exosomes.

PubMed

Mokarizadeh, Aram; Delirezh, Nowruz; Morshedi, Ahhmad; Mosayebi, Ghasem; Farshid, Amir-Abbas; Dalir-Naghadeh, Bahram

2012-01-01

Auto-reactive cells-mediated immune responses are responsible for the current tissue damages during autoimmunity. Accordingly, functional modulation of auto-reactive cells has been a pivotal aim in many of recent studies. In the current study, we investigated the possibility for insertion of regulatory molecules onto auto-reactive cells through exosomal nano-shuttles as a novel approach for phenotype modification of auto-reactive cells. The exosomes were isolated from supernatant of mesenchymal stem cells culture. Resultant exosomes co-cultured with lymphocytes were harvested from established EAE mice in the presence of antigenic MOG35-55 peptide. After 24 hr, insertion of exosomal tolerogenic molecules (PD-L1, TGF-β, galectin-1) onto auto-reactive cells were explored through flow cytometry. The potency of exosomal inserted membrane molecules to modulate phenotype of auto-reactive lymphocytes was assessed upon ELISA test for their-derived cytokines IFN-γ and IL-17. Incorporation of exosomal molecules into lymohocytes' membrane was confirmed by flow cytometric analyses for surface levels of mentioned molecules. Additionally, the decreased secretion of IFN-γ and IL-17 were detected in exosome pre-treated lymphocytes upon stimulation with MOG peptide. Mesenchymal stem cells -derived exosomes showed to be efficient organelles for insertion of bioactive tolerogenic molecules onto auto-reactive cells and modulation of their phenotypes.

Biological Sensitivity to Context: The Interactive Effects of Stress Reactivity and Family Adversity on Socioemotional Behavior and School Readiness

ERIC Educational Resources Information Center

Obradovic, Jelena; Bush, Nicole R.; Stamperdahl, Juliet; Adler, Nancy E.; Boyce, W. Thomas

2010-01-01

This study examined the direct and interactive effects of stress reactivity and family adversity on socioemotional and cognitive development in three hundred and thirty-eight 5- to 6-year-old children. Neurobiological stress reactivity was measured as respiratory sinus arrhythmia and salivary cortisol responses to social, cognitive, sensory, and…

Modifying Memory: Selectively Enhancing and Updating Personal Memories for a Museum Tour by Reactivating Them

PubMed Central

St. Jacques, Peggy L.; Schacter, Daniel L.

2013-01-01

Memory can be modified when reactivated, but little is known about how the properties and extent of reactivation can selectively affect subsequent memory. We developed a novel museum paradigm to directly investigate reactivation-induced plasticity for personal memories. Participants reactivated memories triggered by photos taken from a camera they wore during a museum tour and made relatedness judgments on novel photos taken from a different tour of the same museum. Subsequent recognition memory for events at the museum was better for memories that were highly reactivated (i.e., the retrieval cues during reactivation matched the encoding experience) than for memories that were reactivated at a lower level (i.e., the retrieval cues during reactivation mismatched the encoding experience), but reactivation also increased false recognition of photographs depicting stops that were not experienced during the museum tour. Reactivation thus enables memories to be selectively enhanced and distorted via updating, thereby supporting the dynamic and flexible nature of memory. PMID:23406611

Mindfulness and reduced cognitive reactivity to sad mood: evidence from a correlational study and a non-randomized waiting list controlled study.

PubMed

Raes, Filip; Dewulf, David; Van Heeringen, Cees; Williams, J Mark G

2009-07-01

Cognitive Reactivity (CR) refers to the degree to which a mild dysphoric state reactivates negative thinking patterns, and it has been found to play a key causal role in depressive relapse. Although Mindfulness-Based Cognitive Therapy (MBCT) directly aims to address this mechanism of CR, the relationship between mindfulness and CR has not been tested to date. Using a cross-sectional design (Study 1; n = 164) and a non-randomized waiting list controlled design (Study 2; MBCT [n = 18] vs. waiting list [n = 21]), the authors examined the relationship between naturally occurring levels of mindfulness (Study 1) and MBCT (Study 2) on the one hand, and CR on the other hand. In line with predictions, it was found that (a) trait mindfulness is significantly negatively correlated with CR, even when controlled for current depressive symptoms and prior history of depression (Study 1), and that (b) MBCT, compared to a matched control group, significantly reduces CR, and that this effect of MBCT on reduction of CR is mediated by a positive change in mindfulness skills (Study 2). Results provide first evidence for the claim that mindfulness practices in MBCT are designed to address the process of CR.

An ionization region model of the reactive Ar/O2 high power impulse magnetron sputtering discharge

NASA Astrophysics Data System (ADS)

Gudmundsson, J. T.; Lundin, D.; Brenning, N.; Raadu, M. A.; Huo, Chunqing; Minea, T. M.

2016-12-01

A new reactive ionization region model (R-IRM) is developed to describe the reactive Ar/O2 high power impulse magnetron sputtering (HiPIMS) discharge with a titanium target. It is then applied to study the temporal behavior of the discharge plasma parameters such as electron density, the neutral and ion composition, the ionization fraction of the sputtered vapor, the oxygen dissociation fraction, and the composition of the discharge current. We study and compare the discharge properties when the discharge is operated in the two well established operating modes, the metal mode and the poisoned mode. Experimentally, it is found that in the metal mode the discharge current waveform displays a typical non-reactive evolution, while in the poisoned mode the discharge current waveform becomes distinctly triangular and the current increases significantly. Using the R-IRM we explore the current increase and find that when the discharge is operated in the metal mode Ar+ and Ti+ -ions contribute most significantly (roughly equal amounts) to the discharge current while in the poisoned mode the Ar+ -ions contribute most significantly to the discharge current and the contribution of O+ -ions, Ti+ -ions, and secondary electron emission is much smaller. Furthermore, we find that recycling of atoms coming from the target, that are subsequently ionized, is required for the current generation in both modes of operation. From the R-IRM results it is found that in the metal mode self-sputter recycling dominates and in the poisoned mode working gas recycling dominates. We also show that working gas recycling can lead to very high discharge currents but never to a runaway. It is concluded that the dominating type of recycling determines the discharge current waveform.

OH radical "life expectancy" within and above the Amazon rainforest: vertical, diel and seasonal variations

NASA Astrophysics Data System (ADS)

Nölscher, A.; Yanez-Serrano, A. M.; Kesselmeier, J.; Artaxo, P. P.; Wolff, S.; Trebs, I.; Williams, J.

2013-12-01

The Amazon rainforest forest is the world's largest contiguous ecosystem. Being about 6 million km2 it is around two thirds the area of the United States. The Amazon forest plays an important part of the Earth's hydrological, energy and carbon cycles. Photosynthetic uptake of CO2 by the rainforest affects the global radiative budget and concomitant release of reactive biogenic volatile organic compounds (BVOCs) can directly impact the atmosphere's primary oxidant, the hydroxyl (OH) radical as well as aerosol production and growth. Direct measurement of the total atmospheric OH reactivity (or inverse OH lifetime), in parallel with the individual BVOC can reveal insights into the coupling between biogenic emissions, atmospheric oxidation processes, canopy transport, and the OH budget. In this study we present for the first time, vertical profiles of total OH reactivity and biogenic VOCs that were monitored simultaneously throughout dry season, wet season and transition periods, from a remote tropical rainforest site in the Amazon (Amazonian Tall Tower Observatory (ATTO), S 02°08'38.8'', W 58°59'59.5'', 120 m above sea level, 150 km NE of the city of Manaus, Brazil). The profiles consisted of sequential measurements at 0.05m, 0.5m, 4 m, 12m, 24m, 38m, 53m and 79m, a single profile taking 16 minutes to complete. The measurements were made using Proton Transfer Reaction Mass Spectrometry (PTR-MS), directly in the case of BVOC and using the Comparative Reactivity Method pre-reactor for total OH reactivity. The vertical, diel and seasonal variations in total OH reactivity will be discussed. Total OH reactivity and isoprene profiles were observed to vary strongly between the seasons. Biogenic emissions from the canopy impacted the measurements as well as photo-oxidation, turbulent mixing, and deposition. Tower in the Amazon rainforest for measurements of vertical profiles of BVOCs and total OH reactivity from the forest floor, through the canopy, up to 80m.

PDF methods for turbulent reactive flows

NASA Technical Reports Server (NTRS)

Hsu, Andrew T.

1995-01-01

Viewgraphs are presented on computation of turbulent combustion, governing equations, closure problem, PDF modeling of turbulent reactive flows, validation cases, current projects, and collaboration with industry and technology transfer.

Method for treating reactive metals in a vacuum furnace

DOEpatents

Hulsey, W.J.

1975-10-28

The invention is directed to a method for reducing the contamination of reactive metal melts in vacuum furnaces due to the presence of residual gaseous contaminants in the furnace atmosphere. This reduction is achieved by injecting a stream of inert gas directly over the metal confined in a substantially closed crucible with the flow of the gas being sufficient to establish a pressure differential between the interior of the crucible and the furnace atmosphere.

Precise through-space control of an abiotic electrophilic aromatic substitution reaction

NASA Astrophysics Data System (ADS)

Murphy, Kyle E.; Bocanegra, Jessica L.; Liu, Xiaoxi; Chau, H.-Y. Katharine; Lee, Patrick C.; Li, Jianing; Schneebeli, Severin T.

2017-04-01

Nature has evolved selective enzymes for the efficient biosynthesis of complex products. This exceptional ability stems from adapted enzymatic pockets, which geometrically constrain reactants and stabilize specific reactive intermediates by placing electron-donating/accepting residues nearby. Here we perform an abiotic electrophilic aromatic substitution reaction, which is directed precisely through space. Ester arms--positioned above the planes of aromatic rings--enable it to distinguish between nearly identical, neighbouring reactive positions. Quantum mechanical calculations show that, in two competing reaction pathways, both [C-H...O]-hydrogen bonding and electrophile preorganization by coordination to a carbonyl group likely play a role in controlling the reaction. These through-space-directed mechanisms are inspired by dimethylallyl tryptophan synthases, which direct biological electrophilic aromatic substitutions by preorganizing dimethylallyl cations and by stabilizing reactive intermediates with [C-H...N]-hydrogen bonding. Our results demonstrate how the third dimension above and underneath aromatic rings can be exploited to precisely control electrophilic aromatic substitutions.

Stress controlled pulsed direct current co-sputtered Al{sub 1−x}Sc{sub x}N as piezoelectric phase for micromechanical sensor applications

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

Fichtner, Simon, E-mail: sif@tf.uni-kiel.de; Reimer, Tim; Chemnitz, Steffen

2015-11-01

Scandium alloyed aluminum nitride (Al{sub 1−x}Sc{sub x}N) thin films were fabricated by reactive pulsed direct current co-sputtering of separate scandium and aluminum targets with x ≤ 0.37. A significant improvement of the clamped transversal piezoelectric response to strain e{sub 31,f} from −1.28 C/m{sup 2} to −3.01 C/m{sup 2} was recorded, while dielectric constant and loss angle remain low. Further, the built-in stress level of Al{sub 1−x}Sc{sub x}N was found to be tuneable by varying pressure, Ar/N{sub 2} ratio, and Sc content. The thus resulting enhancement of the expectable signal to noise ratio by a factor of 2.1 and the abilitymore » to control built-in stress make the integration of Al{sub 1−x}Sc{sub x}N as the piezoelectric phase of micro-electro-mechanical system sensor applications highly attractive.« less

N channel JFET based digital logic gate structure

NASA Technical Reports Server (NTRS)

Krasowski, Michael J. (Inventor)

2010-01-01

A circuit topography is presented which is used to create usable digital logic gates using N (negatively doped) channel Junction Field Effect Transistors (JFETs) and load resistors, level shifting resistors, and supply rails whose values are based on the direct current (DC) parametric distributions of those JFETs. This method has direct application to the current state of the art in high temperature, for example 300.degree. C. to 500.degree. C. and higher, silicon carbide (SiC) device production. The ability to produce inverting and combinatorial logic enables the production of pulse and edge triggered latches. This scale of logic synthesis would bring digital logic and state machine capabilities to devices operating in extremely hot environments, such as the surface of Venus, near hydrothermal vents, within nuclear reactors (SiC is inherently radiation hardened), and within internal combustion engines. The basic logic gate can be configured as a driver for oscillator circuits allowing for time bases and simple digitizers for resistive or reactive sensors. The basic structure of this innovation, the inverter, can be reconfigured into various analog circuit topographies through the use of feedback structures.

Virtual Reality Cue Reactivity Assessment: A Comparison of Treatment- vs. Nontreatment-Seeking Smokers

ERIC Educational Resources Information Center

Bordnick, Patrick S.; Yoon, Jin H.; Kaganoff, Eili; Carter, Brian

2013-01-01

Objectives: The cue-reactivity paradigm has been widely used to assess craving among cigarette smokers. Seeking to replicate and expand on previous virtual reality (VR) nicotine cue-reactivity research on nontreatment-seeking smokers, the current study compared subjective reports of craving for cigarettes when exposed to smoking (proximal and…

Principles for integrating reactive species into in vivo biological processes: Examples from exercise physiology.

PubMed

Margaritelis, Nikos V; Cobley, James N; Paschalis, Vassilis; Veskoukis, Aristidis S; Theodorou, Anastasios A; Kyparos, Antonios; Nikolaidis, Michalis G

2016-04-01

The equivocal role of reactive species and redox signaling in exercise responses and adaptations is an example clearly showing the inadequacy of current redox biology research to shed light on fundamental biological processes in vivo. Part of the answer probably relies on the extreme complexity of the in vivo redox biology and the limitations of the currently applied methodological and experimental tools. We propose six fundamental principles that should be considered in future studies to mechanistically link reactive species production to exercise responses or adaptations: 1) identify and quantify the reactive species, 2) determine the potential signaling properties of the reactive species, 3) detect the sources of reactive species, 4) locate the domain modified and verify the (ir)reversibility of post-translational modifications, 5) establish causality between redox and physiological measurements, 6) use selective and targeted antioxidants. Fulfilling these principles requires an idealized human experimental setting, which is certainly a utopia. Thus, researchers should choose to satisfy those principles, which, based on scientific evidence, are most critical for their specific research question. Copyright © 2015 Elsevier Inc. All rights reserved.

Allogeneic substitution for nominal antigen-specific T-cell clone reactivity in schistosomiasis.

PubMed Central

Linette, G P; Lammie, P J; Phillips, S M

1986-01-01

The present studies have established the nature of a T-cell clone which demonstrates dual reactivity directed against Schistosoma mansoni antigen presented by syngeneic antigen presenting cells and against allogeneic cells. Clone G4, when stimulated by either antigen (SEA) or allogeneic cells (PL/J), exhibits similar functional and phenotypic characteristics. A subclone of G4, G4A.1, which has been maintained in continuous mixed lymphocyte culture for 12 months (in the absence of SEA), retains comparable reactivity with respect to proliferation and ability to produce lymphokines, transfer delayed-type hypersensitivity, and produce in vitro granulomas in response to SEA. Normal antigenic stimulation is highly contingent upon I-Ab compatibility while antibody blocking experiments map allo-reactivity to I-Eu. The failure of B10.PL spleen cells to stimulate G4, however, suggests that alloreactivity may be directed against the recently described Mls X locus. Both allogeneic and nominal antigen induced T-cell activation are blocked by antibody directed against L3T4A, confirming Class II MHC restriction for both types of stimulation. These studies suggest that stimulation of T cells by either alloantigen or nominal antigen elicits qualitatively similar functional profiles, and further suggest the feasibility of producing large numbers of nominal antigen reactive cloned T cells in the absence of nominal antigen under mixed lymphocyte culture conditions. PMID:2420707

Comparison of techniques of detecting immunoglobulin-binding protein reactivity to immunoglobulin produced by different avian and mammalian species.

PubMed

Justiz-Vaillant, A A; Akpaka, P E; McFarlane-Anderson, N; Smikle, M F

2013-01-01

The rationale of this study was to use several immunological assays to investigate the reactivity of immunoglobulin binding protein (IBP) to immunoglobulins from various avian and mammalian species. The IBP studied were Staphylococcal protein A (SpA), Streptococcal protein G (SpG), Peptostreptococcal protein L (SpL) and recombinant protein LA (SpLA). The various immunological techniques used were double immunodiffusion (Ouchterlony technique) that tested positive high protein reactivities, direct and competitive enzyme-linked immunosorbent assays (ELISAs) that tested moderate and low positive protein binding capacities, respectively. In addition to sandwich ELISAs, immunoblot analyses and Ig-purification by SpA-affinity chromatography, which were sensitive tests and helpful in the screening and confirmatory tests were also used. The Ouchterlony technique showed that compared to the other proteins, SpLA had the highest range of reactivity with animal sera and purified immunoglobulins while SpL was least reactive. With the direct ELISA, SpL reacted with the raccoon sera, rabbit IgG and with IgY from bantam hens and pigeons. While with the direct ELISA, SpA reacted with sera from skunk, coyote, raccoon, mule, donkey and human. The sandwich ELISA revealed high reactivity of both SpG and SpLA with mammalian sera titres ranging from 1:32 (raccoon serum) to 1:1024 (mule and donkey sera). These results suggest that IBP can be used for the detection of immunoglobulin using various immunological assays and this is important for the diagnosis of infectious diseases in animal and bird populations studied and in the purification of immunoglobulins.

Examining Hepatitis, A and B Vaccination, and HBV Reactivation Monitoring During Direct-Acting Antiviral Therapy for Hepatitis C.

PubMed

Davison, John; O'Shea, Amy; Waterbury, Nancee; Villalvazo, Yolanda

2018-05-30

The objective of this study was to examine Hepatitis A (HAV) and Hepatitis B (HBV) screening, and the risk of HBV reactivation during Hepatitis C (HCV) therapy with direct-acting antivirals (DAAs). A retrospective chart review was performed of patients treated with second generation DAA therapy from January 2014 to September 2016 at the Iowa City VA Healthcare System. In total 409 patients initiated HCV treatment, 308 (75%) and 241 (59%) were HAV and HBV vaccine eligible, respectively. Among those, 24 (8%) received a HAV vaccine, while only 20 (8%) received a HBV vaccine. Of these, 7 patients initiating an immunization in the clinic had record of completing the series. Further, 101 patients had a reactive Hepatitis B core Antibody indicating previous HBV infection, and 3 of these were tested for HBV reactivation during HCV therapy. Overall, the assessment found low rates of HAV and HBV vaccine administration, indicating missed opportunities for preventative care during HCV therapy. With the known risk of HBV reactivation with DAAs, the need for HAV and HBV screening is essential.

Oblique contractional reactivation of inherited heterogeneities: Cause for arcuate orogens

PubMed Central

Sokoutis, D.; Willingshofer, E.; Brun, J.‐P.; Gueydan, F.; Cloetingh, S.

2017-01-01

Abstract We use lithospheric‐scale analog models to study the reactivation of pre‐existing heterogeneities under oblique shortening and its relation to the origin of arcuate orogens. Reactivation of inherited rheological heterogeneities is an important mechanism for localization of deformation in compressional settings and consequent initiation of contractional structures during orogenesis. However, the presence of an inherited heterogeneity in the lithosphere is in itself not sufficient for its reactivation once the continental lithosphere is shortened. The heterogeneity orientation is important in determining if reactivation occurs and to which extent. This study aims at giving insights on this process by means of analog experiments in which a linear lithospheric heterogeneity trends with various angles to the shortening direction. In particular, the key parameter investigated is the orientation (angle α) of a strong domain (SD) with respect to the shortening direction. Experimental results show that angles α ≥ 75° (high obliquity) allow for reactivation along the entire SD and the development of a linear orogen. For α ≤ 60° (low obliquity) the models are characterized by the development of an arcuate orogen, with the SD remaining partially non‐reactivated. These results provide a new mechanism for the origin of some arcuate orogens, in which orocline formation was not driven by indentation or subduction processes, but by oblique shortening of inherited heterogeneities, as exemplified by the Ouachita orogen of the southern U.S. PMID:28670046

Reactivation of Herpesvirus in Patients With Hepatitis C Treated With Direct-Acting Antiviral Agents.

PubMed

Perelló M, Christie; Fernández-Carrillo, Carlos; Londoño, María-Carlota; Arias-Loste, Teresa; Hernández-Conde, Marta; Llerena, Susana; Crespo, Javier; Forns, Xavier; Calleja, José Luis

2016-11-01

We performed a case-series analysis of reactivation of herpesvirus in patients with hepatitis C virus (HCV) infection treated with direct-acting antiviral (DAA) agents. We collected data from 576 patients with HCV infection treated with DAA combinations at 3 hospitals in Spain, from November 2014 through November 2015. We also collected data from a control population (230 HCV-infected patients, matched for sex and age; 23 untreated and 213 treated with interferon-based regimens). Herpesvirus was reactivated in 10 patients who received DAA therapy (7 patients had cirrhosis and 3 patients had received liver transplants), a median of 8 weeks after the therapy was initiated. None of the controls had herpesvirus reactivation. Patients with herpesvirus reactivation were receiving the DAA agents sofosbuvir with ledipasvir (with or without ribavirin, 7/10), ombitasvir with paritaprevir and ritonavir plus dasabuvir (with or without ribavirin, 2/10), or sofosbuvir with simeprevir plus ribavirin (1/10). Two of the 10 patients developed postherpetic neuralgia and 1 patient developed kerato-uveitis. All 10 patients with herpesvirus reactivation achieved a sustained virologic response. Immune changes that follow clearance of HCV might lead to reactivation of other viruses, such as herpesvirus. Patients with HCV infection suspected of having herpesvirus infection should be treated immediately. Some groups also might be screened for herpesvirus infection. Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.

Real Time Voltage and Current Phase Shift Analyzer for Power Saving Applications

PubMed Central

Krejcar, Ondrej; Frischer, Robert

2012-01-01

Nowadays, high importance is given to low energy devices (such as refrigerators, deep-freezers, washing machines, pumps, etc.) that are able to produce reactive power in power lines which can be optimized (reduced). Reactive power is the main component which overloads power lines and brings excessive thermal stress to conductors. If the reactive power is optimized, it can significantly lower the electricity consumption (from 10 to 30%—varies between countries). This paper will examine and discuss the development of a measuring device for analyzing reactive power. However, the main problem is the precise real time measurement of the input and output voltage and current. Such quality measurement is needed to allow adequate action intervention (feedback which reduces or fully compensates reactive power). Several other issues, such as the accuracy and measurement speed, must be examined while designing this device. The price and the size of the final product need to remain low as they are the two important parameters of this solution. PMID:23112662

16,000-rpm Interior Permanent Magnet Reluctance Machine with Brushless Field Excitation

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

Hsu, J.S.; Burress, T.A.; Lee, S.T.

2007-10-31

The reluctance interior permanent magnet (RIPM) motor is currently used by many leading auto manufacturers for hybrid vehicles. The power density for this type of motor is high compared with that of induction motors and switched reluctance motors. The primary drawback of the RIPM motor is the permanent magnet (PM) because during high-speed operation, the fixed PM produces a huge back electromotive force (emf) that must be reduced before the current will pass through the stator windings. This reduction in back-emf is accomplished with a significant direct-axis (d-axis) demagnetization current, which opposes the PM's flux to reduce the flux seenmore » by the stator wires. This may lower the power factor and efficiency of the motor and raise the requirement on the alternate current (ac) power supply; consequently, bigger inverter switching components, thicker motor winding conductors, and heavier cables are required. The direct current (dc) link capacitor is also affected when it must accommodate heavier harmonic currents. It is commonly agreed that, for synchronous machines, the power factor can be optimized by varying the field excitation to minimize the current. The field produced by the PM is fixed and cannot be adjusted. What can be adjusted is reactive current to the d-axis of the stator winding, which consumes reactive power but does not always help to improve the power factor. The objective of this project is to avoid the primary drawbacks of the RIPM motor by introducing brushless field excitation (BFE). This offers both high torque per ampere (A) per core length at low speed by using flux, which is enhanced by increasing current to a fixed excitation coil, and flux, which is weakened at high speed by reducing current to the excitation coil. If field weakening is used, the dc/dc boost converter used in a conventional RIPM motor may be eliminated to reduce system costs. However, BFE supports a drive system with a dc/dc boost converter, because it can further extend the constant power speed range of the drive system and adjust the field for power factor and efficiency gains. Lower core losses at low torque regions, especially at high speeds, are attained by reducing the field excitation. Safety and reliability are increased by weakening the field when a winding short-circuit fault occurs, preventing damage to the motor. For a high-speed motor operating at 16,000-revolutions per minute (rpm), mechanical stress is a challenge. Bridges that link the rotor punching segments together must be thickened for mechanical integrity; consequently, increased rotor flux leakage significantly lowers motor performance. This barrier can be overcome by BFE to ensure sufficient rotor flux when needed.« less

The Antitumor Effect of Single-domain Antibodies Directed Towards Membrane-associated Catalase and Superoxide Dismutase.

PubMed

Bauer, Georg; Motz, Manfred

2016-11-01

Neutralizing single-domain antibodies directed towards catalase or superoxide dismutase (SOD) caused efficient reactivation of intercellular reactive oxygen species/reactive nitrogen species (ROS/RNS)-dependent apoptosis-inducing signaling specifically in human tumor cells. Single-domain antibodies targeted tumor cell-specific membrane-associated SOD and catalase, but not the corresponding intracellular enzymes. They were shown to be about 200-fold more effective than corresponding classical recombinant antigen-binding fragments and more than four log steps more efficient than monoclonal antibodies. Combined addition of single-domain antibodies against catalase and SOD caused a remarkable synergistic effect. Proof-of-concept experiments in immunocompromised mice using human tumor xenografts and single-domain antibodies directed towards SOD showed an inhibition of tumor growth. Neutralizing single-domain antibodies directed to catalase and SOD also caused a very strong synergistic effect with the established chemotherapeutic agent taxol, indicating an overlap of signaling pathways. This effect might also be useful in order to avoid unwanted side-effects and to drastically lower the costs for taxol-based therapy. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Growth of multiwalled-carbon nanotubes using vertically aligned carbon nanofibers as templates/scaffolds and improved field-emission properties

NASA Astrophysics Data System (ADS)

Cui, H.; Yang, X.; Baylor, L. R.; Lowndes, D. H.

2005-01-01

Multiwalled-carbon nanotubes (MWCNTs) are grown on top of vertically aligned carbon nanofibers (VACNFs) via microwave plasma-enhanced chemical vapor deposition (MPECVD). The VACNFs are first grown in a direct-current plasma-enhanced chemical vapor deposition reactor using nickel catalyst. A layer of carbon-silicon materials is then deposited on the VACNFs and the nickel catalyst particle is broken down into smaller nanoparticles during an intermediate reactive-ion-plasma deposition step. These nickel nanoparticles nucleate and grow MWCNTs in the following MPECVD process. Movable-probe measurements show that the MWCNTs have greatly improved field-emission properties relative to the VACNFs.

Prediction of mass transfer coefficients in non-Newtonian fermentation media using first-principles methods.

PubMed

Radl, Stefan; Khinast, Johannes G

2007-08-01

Bubble flows in non-Newtonian fluids were analyzed using first-principles methods with the aim to compute and predict mass transfer coefficients in such fermentation media. The method we used is a Direct Numerical Simulation (DNS) of the reactive multiphase flow with deformable boundaries and interfaces. With this method, we are able for the first time to calculate mass transfer coefficients in non-Newtonian liquids of different rheologies without any experimental data. In the current article, shear-thinning fluids are considered. However, the results provide the basis for further investigations, such as the study of viscoelastic fluids. (c) 2007 Wiley Periodicals, Inc.

Chemopreventive Strategies for Inflammation-Related Carcinogenesis: Current Status and Future Direction.

PubMed

Kanda, Yusuke; Osaki, Mitsuhiko; Okada, Futoshi

2017-04-19

A sustained and chronically-inflamed environment is characterized by the presence of heterogeneous inflammatory cellular components, including neutrophils, macrophages, lymphocytes and fibroblasts. These infiltrated cells produce growth stimulating mediators (inflammatory cytokines and growth factors), chemotactic factors (chemokines) and genotoxic substances (reactive oxygen species and nitrogen oxide) and induce DNA damage and methylation. Therefore, chronic inflammation serves as an intrinsic niche for carcinogenesis and tumor progression. In this article, we summarize the up-to-date findings regarding definitive/possible causes and mechanisms of inflammation-related carcinogenesis derived from experimental and clinical studies. We also propose 10 strategies, as well as candidate agents for the prevention of inflammation-related carcinogenesis.

Is blunted cardiovascular reactivity in depression mood-state dependent? A comparison of major depressive disorder remitted depression and healthy controls.

PubMed

Salomon, Kristen; Bylsma, Lauren M; White, Kristi E; Panaite, Vanessa; Rottenberg, Jonathan

2013-10-01

Prior work has repeatedly demonstrated that people who have current major depression exhibit blunted cardiovascular reactivity to acute stressors (e.g., Salomon et al., 2009). A key question regards the psychobiological basis for these deficits, including whether such deficits are depressed mood-state dependent or whether these effects are trait-like and are observed outside of depression episodes in vulnerable individuals. To examine this issue, we assessed cardiovascular reactivity to a speech stressor task and a forehead cold pressor in 50 individuals with current major depressive disorder (MDD), 25 with remitted major depression (RMD), and 45 healthy controls. Heart rate (HR), blood pressure and impedance cardiography were assessed and analyses controlled for BMI and sex. Significant group effects were found for SBP, HR, and PEP for the speech preparation period and HR, CO, and PEP during the speech. For each of these parameters, only the MDD group exhibited attenuated reactivity as well as impaired SBP recovery. Reactivity and recovery in the RMD group more closely resembled the healthy controls. Speeches given by the MDD group were rated as less persuasive than the RMD or healthy controls' speeches. No significant differences were found for the cold pressor. Blunted cardiovascular reactivity and impaired recovery in current major depression may be mood-state dependent phenomena and may be more reflective of motivational deficits than deficits in the physiological integrity of the cardiovascular system. Copyright © 2013 Elsevier B.V. All rights reserved.

Is blunted cardiovascular reactivity in depression mood-state dependent? A comparison of major depressive disorder remitted depression and healthy controls

PubMed Central

Salomon, Kristen; Bylsma, Lauren M.; White, Kristi E.; Panaite, Vanessa; Rottenberg, Jonathan

2015-01-01

Prior work has repeatedly demonstrated that people who have current major depression exhibit blunted cardiovascular reactivity to acute stressors (e.g., Salomon et al., 2009). A key question regards the psychobiological basis for these deficits, including whether such deficits are depressed mood-state dependent or whether these effects are trait-like and are observed outside of depression episodes invulnerable individuals. To examine this issue, we assessed cardiovascular reactivity to a speech stressor task and a forehead cold pressor in 50 individuals with current major depressive disorder (MDD), 25 with remitted major depression (RMD), and 45 healthy controls. Heart rate (HR), blood pressure and impedance cardiography were assessed and analyses controlled for BMI and sex. Significant group effects were found for SBP, HR, and PEP for the speech preparation period and HR, CO, and PEP during the speech. For each of these parameters, only the MDD group exhibited attenuated reactivity as well as impaired SBP recovery. Reactivity and recovery in the RMD group more closely resembled the healthy controls. Speeches given by the MDD group were rated as less persuasive than the RMD or healthy controls' speeches. No significant differences were found for the cold pressor. Blunted cardiovascular reactivity and impaired recovery in current major depression may be mood-state dependent phenomena and may be more reflective of motivational deficits than deficits in the physiological integrity of the cardiovascular system. PMID:23756147

Bidirectional Associations between Peer Victimization and Functions of Aggression in Middle Childhood: Further Evaluation across Informants and Academic Years.

PubMed

Cooley, John L; Fite, Paula J; Pederson, Casey A

2018-01-01

The current 3-wave study examined bidirectional associations between peer victimization and functions of aggression across informants over a 1-year period in middle childhood, with attention to potential gender differences. Participants included 198 children (51% girls) in the third and fourth grades and their homeroom teachers. Peer victimization was assessed using both child- and teacher-reports, and teachers provided ratings of reactive and proactive aggression. Cross-classified multilevel cross-lagged models indicated that child-reports, but not teacher-reports, of peer victimization predicted higher levels of reactive aggression within and across academic years. Further, reactive aggression predicted subsequent increases in child- and teacher-reports of peer victimization across each wave of data. Several gender differences, particularly in the crossed paths between proactive aggression and peer victimization, also emerged. Whereas peer victimization was found to partially account for the stability of reactive aggression over time, reactive aggression did not account for the stability of peer victimization. Taken together with previous research, the current findings suggest that child-reports of peer victimization may help identify youth who are risk for exhibiting increased reactive aggression over time. Further, they highlight the need to target reactively aggressive behavior for the prevention of peer victimization in middle childhood.

Mapping Proteome-Wide Interactions of Reactive Chemicals Using Chemoproteomic Platforms

PubMed Central

Counihan, Jessica L.; Ford, Breanna; Nomura, Daniel K.

2015-01-01

A large number of pharmaceuticals, endogenous metabolites, and environmental chemicals act through covalent mechanisms with protein targets. Yet, their specific interactions with the proteome still remain poorly defined for most of these reactive chemicals. Deciphering direct protein targets of reactive small-molecules is critical in understanding their biological action, off-target effects, potential toxicological liabilities, and development of safer and more selective agents. Chemoproteomic technologies have arisen as a powerful strategy that enable the assessment of proteome-wide interactions of these irreversible agents directly in complex biological systems. We review here several chemoproteomic strategies that have facilitated our understanding of specific protein interactions of irreversibly-acting pharmaceuticals, endogenous metabolites, and environmental electrophiles to reveal novel pharmacological, biological, and toxicological mechanisms. PMID:26647369

Biological Sensitivity to Context: The Interactive Effects of Stress Reactivity and Family Adversity on Socio-Emotional Behavior and School Readiness

PubMed Central

Obradović, Jelena; Bush, Nicole R.; Stamperdahl, Juliet; Adler, Nancy E.; Boyce, W. Thomas

2009-01-01

This study examined the direct and interactive effects of stress reactivity and family adversity on socio-emotional and cognitive development in 338 five-to-six-year-old children. Neurobiological stress reactivity was measured as respiratory sinus arrhythmia and salivary cortisol responses to social, cognitive, sensory, and emotional challenges. Adaptation was assessed using child, parent, and teacher reports of externalizing symptoms, prosocial behaviors, school engagement, and academic competence. Results revealed significant interactions between reactivity and adversity. High stress reactivity was associated with more maladaptive outcomes in the context of high adversity but with better adaption in the context of low adversity. The findings corroborate a reconceptualization of stress reactivity as biological sensitivity to context by showing that high reactivity can both hinder and promote adaptive functioning. PMID:20331667

Reactive Oxygen Species Tune Root Tropic Responses1[OPEN

PubMed Central

Krieger, Gat

2016-01-01

The default growth pattern of primary roots of land plants is directed by gravity. However, roots possess the ability to sense and respond directionally to other chemical and physical stimuli, separately and in combination. Therefore, these root tropic responses must be antagonistic to gravitropism. The role of reactive oxygen species (ROS) in gravitropism of maize and Arabidopsis (Arabidopsis thaliana) roots has been previously described. However, which cellular signals underlie the integration of the different environmental stimuli, which lead to an appropriate root tropic response, is currently unknown. In gravity-responding roots, we observed, by applying the ROS-sensitive fluorescent dye dihydrorhodamine-123 and confocal microscopy, a transient asymmetric ROS distribution, higher at the concave side of the root. The asymmetry, detected at the distal elongation zone, was built in the first 2 h of the gravitropic response and dissipated after another 2 h. In contrast, hydrotropically responding roots show no transient asymmetric distribution of ROS. Decreasing ROS levels by applying the antioxidant ascorbate, or the ROS-generation inhibitor diphenylene iodonium attenuated gravitropism while enhancing hydrotropism. Arabidopsis mutants deficient in Ascorbate Peroxidase 1 showed attenuated hydrotropic root bending. Mutants of the root-expressed NADPH oxidase RBOH C, but not rbohD, showed enhanced hydrotropism and less ROS in their roots apices (tested in tissue extracts with Amplex Red). Finally, hydrostimulation prior to gravistimulation attenuated the gravistimulated asymmetric ROS and auxin signals that are required for gravity-directed curvature. We suggest that ROS, presumably H2O2, function in tuning root tropic responses by promoting gravitropism and negatively regulating hydrotropism. PMID:27535793

BIOMONITORING OF REACTIVE OXYGEN SPECIES IN BIOLOGICAL FLUIDS

EPA Science Inventory

Elevated levels of reactive oxygen species (ROS) are associated with several disease processes in humans, including cancer, asthma, diabetes, and cardiac disease. We have explored whether ROS can be measured directly in human fluids, and their value as a biomarker of exposure an...

Sleeping on the rubber-hand illusion: Memory reactivation during sleep facilitates multisensory recalibration.

PubMed

Honma, Motoyasu; Plass, John; Brang, David; Florczak, Susan M; Grabowecky, Marcia; Paller, Ken A

2016-01-01

Plasticity is essential in body perception so that physical changes in the body can be accommodated and assimilated. Multisensory integration of visual, auditory, tactile, and proprioceptive signals contributes both to conscious perception of the body's current state and to associated learning. However, much is unknown about how novel information is assimilated into body perception networks in the brain. Sleep-based consolidation can facilitate various types of learning via the reactivation of networks involved in prior encoding or through synaptic down-scaling. Sleep may likewise contribute to perceptual learning of bodily information by providing an optimal time for multisensory recalibration. Here we used methods for targeted memory reactivation (TMR) during slow-wave sleep to examine the influence of sleep-based reactivation of experimentally induced alterations in body perception. The rubber-hand illusion was induced with concomitant auditory stimulation in 24 healthy participants on 3 consecutive days. While each participant was sleeping in his or her own bed during intervening nights, electrophysiological detection of slow-wave sleep prompted covert stimulation with either the sound heard during illusion induction, a counterbalanced novel sound, or neither. TMR systematically enhanced feelings of bodily ownership after subsequent inductions of the rubber-hand illusion. TMR also enhanced spatial recalibration of perceived hand location in the direction of the rubber hand. This evidence for a sleep-based facilitation of a body-perception illusion demonstrates that the spatial recalibration of multisensory signals can be altered overnight to stabilize new learning of bodily representations. Sleep-based memory processing may thus constitute a fundamental component of body-image plasticity.

Immunization with Hypoallergens of shrimp allergen tropomyosin inhibits shrimp tropomyosin specific IgE reactivity.

PubMed

Wai, Christine Y Y; Leung, Nicki Y H; Ho, Marco H K; Gershwin, Laurel J; Shu, Shang An; Leung, Patrick S C; Chu, Ka Hou

2014-01-01

Designer proteins deprived of its IgE-binding reactivity are being sought as a regimen for allergen-specific immunotherapy. Although shrimp tropomyosin (Met e 1) has long been identified as the major shellfish allergen, no immunotherapy is currently available. In this study, we aim at identifying the Met e 1 IgE epitopes for construction of hypoallergens and to determine the IgE inhibitory capacity of the hypoallergens. IgE-binding epitopes were defined by three online computational models, ELISA and dot-blot using sera from shrimp allergy patients. Based on the epitope data, two hypoallergenic derivatives were constructed by site-directed mutagenesis (MEM49) and epitope deletion (MED171). Nine regions on Met e 1 were defined as the major IgE-binding epitopes. Both hypoallergens MEM49 and MED171 showed marked reduction in their in vitro reactivity towards IgE from shrimp allergy patients and Met e 1-sensitized mice, as well as considerable decrease in induction of mast cell degranulation as demonstrated in passive cutaneous anaphylaxis assay. Both hypoallergens were able to induce Met e 1-recognizing IgG antibodies in mice, specifically IgG2a antibodies, that strongly inhibited IgE from shrimp allergy subjects and Met e 1-sensitized mice from binding to Met e 1. These results indicate that the two designer hypoallergenic molecules MEM49 and MED171 exhibit desirable preclinical characteristics, including marked reduction in IgE reactivity and allergenicity, as well as ability to induce blocking IgG antibodies. This approach therefore offers promises for development of immunotherapeutic regimen for shrimp tropomyosin allergy.

Preventing the Return of Fear Using Reconsolidation Update Mechanisms Depends on the Met-Allele of the Brain Derived Neurotrophic Factor Val66Met Polymorphism.

PubMed

Asthana, Manish Kumar; Brunhuber, Bettina; Mühlberger, Andreas; Reif, Andreas; Schneider, Simone; Herrmann, Martin J

2016-06-01

Memory reconsolidation is the direct effect of memory reactivation followed by stabilization of newly synthesized proteins. It has been well proven that neural encoding of both newly and reactivated memories requires synaptic plasticity. Brain derived neurotrophic factor (BDNF) has been extensively investigated regarding its role in the formation of synaptic plasticity and in the alteration of fear memories. However, its role in fear reconsolidation is still unclear; hence, the current study has been designed to investigate the role of the BDNF val66met polymorphism (rs6265) in fear memory reconsolidation in humans. An auditory fear-conditioning paradigm was conducted, which comprised of three stages (acquisition, reactivation, and spontaneous recovery). One day after fear acquisition, the experimental group underwent reactivation of fear memory followed by the extinction training (reminder group), whereas the control group (non-reminder group) underwent only extinction training. On day 3, both groups were subjected to spontaneous recovery of earlier learned fearful memories. The treat-elicited defensive response due to conditioned threat was measured by assessing the skin conductance response to the conditioned stimulus. All participants were genotyped for rs6265. The results indicate a diminishing effect of reminder on the persistence of fear memory only in the Met-allele carriers, suggesting a moderating effect of the BDNF polymorphism in fear memory reconsolidation. Our findings suggest a new role for BDNF gene variation in fear memory reconsolidation in humans. © The Author 2016. Published by Oxford University Press on behalf of CINP.

Chronic Stress Exposure and Generation Are Related to the P-Factor and Externalizing Specific Psychopathology in Youth.

PubMed

Snyder, Hannah R; Young, Jami F; Hankin, Benjamin L

2017-05-25

Psychopathology is posited to be transdiagnostically linked to chronic stress. Yet efforts to understand the specificity and directionality of these links have been sparse, and the ubiquitous comorbidity of psychopathology has made the seemingly nonspecific links between psychological disorders and chronic stress difficult to interpret. The current study used a latent dimensional bifactor model of psychopathology to account for comorbidity and a multiwave prospective design to disentangle temporal associations between psychopathology and chronic stress longitudinally during the critical adolescent period for psychopathology risk and stress reactivity. A community sample of 567 youth (55.5% female, age M = 11.8 at baseline, M = 15.1 at end of study) were followed prospectively for 3 years, with chronic stress assessed with the Youth Life Stress Interview and psychopathology symptoms assessed via both self and parent report. Exposure to chronic stress predicted what is common across forms of psychopathology (the p factor), which in turn predicted generation of chronic stress over time. After accounting for comorbidity via the p factor, externalizing behaviors also had specific transactional links to chronic stress, whereas links between internalizing psychopathology and chronic stress were completely accounted for by common psychopathology. The results provide the first direct evidence that chronic stress is transdiagnostically and reciprocally linked to psychopathology, during a critical youth period for psychopathology onset and stress reactivity.

Children's biological responsivity to acute stress predicts concurrent cognitive performance.

PubMed

Roos, Leslie E; Beauchamp, Kathryn G; Giuliano, Ryan; Zalewski, Maureen; Kim, Hyoun K; Fisher, Philip A

2018-04-10

Although prior research has characterized stress system reactivity (i.e. hypothalamic-pituitary-adrenal axis, HPAA; autonomic nervous system, ANS) in children, it has yet to examine the extent to which biological reactivity predicts concurrent goal-directed behavior. Here, we employed a stressor paradigm that allowed concurrent assessment of both stress system reactivity and performance on a speeded-response task to investigate the links between biological reactivity and cognitive function under stress. We further investigated gender as a moderator given previous research suggesting that the ANS may be particularly predictive of behavior in males due to gender differences in socialization. In a sociodemographically diverse sample of young children (N = 58, M age = 5.38 yrs; 44% male), individual differences in sociodemographic covariates (age, household income), HPAA (i.e. cortisol), and ANS (i.e. respiratory sinus arrhythmia, RSA, indexing the parasympathetic branch; pre-ejection period, PEP, indexing the sympathetic branch) function were assessed as predictors of cognitive performance under stress. We hypothesized that higher income, older age, and greater cortisol reactivity would be associated with better performance overall, and flexible ANS responsivity (i.e. RSA withdrawal, PEP shortening) would be predictive of performance for males. Overall, females performed better than males. Two-group SEM analyses suggest that, for males, greater RSA withdrawal to the stressor was associated with better performance, while for females, older age, higher income, and greater cortisol reactivity were associated with better performance. Results highlight the relevance of stress system reactivity to cognitive performance under stress. Future research is needed to further elucidate for whom and in what situations biological reactivity predicts goal-directed behavior.

Imaging the Reconstruction of True and False Memories Using Sensory Reactivation and the Misinformation Paradigms

ERIC Educational Resources Information Center

Stark, Craig E. L.; Okado, Yoko; Loftus, Elizabeth F.

2010-01-01

Many current theories of false memories propose that, when we retrieve a memory, we are not reactivating a veridical, fixed representation of a past event, but are rather reactivating incomplete fragments that may be accurate or distorted and may have arisen from other events. By presenting the two phases of the misinformation paradigm in…

Differentiating Challenge Reactivity from Psychomotor Activity in Studies of Children’s Psychophysiology: Considerations for Theory and Measurement

PubMed Central

Bush, Nicole R.; Alkon, Abbey; Obradović, Jelena; Stamperdahl, Juliet; Boyce, W. Thomas

2014-01-01

Current methods of assessing children’s physiologic “stress reactivity” may be confounded by psychomotor activity, biasing estimates of the relation between reactivity and health. We examine the joint and independent contributions of psychomotor activity and challenge reactivity during a protocol for children ages 5–6 (N=338). Measures of parasympathetic (RSA) and sympathetic (PEP) reactivity were calculated for social, cognitive, sensory, and emotional challenge tasks. Reactivity was calculated relative to both resting and a paired comparison task that accounted for psychomotor activity effects during each challenge. Results indicated that comparison tasks themselves elicited RSA and PEP responses, and reactivity adjusted for psychomotor activity was incongruent with reactivity calculated using rest. Findings demonstrate the importance of accounting for confounding psychomotor activity effects on physiologic reactivity. PMID:21524757

Major Depressive Disorder and Impulsive Reactivity to Emotion: Toward a Dual Process View of Depression

PubMed Central

Carver, Charles S.; Johnson, Sheri L.; Joormann, Jutta

2012-01-01

Objective Dual process theories of behavior have been used to suggest that vulnerability to depression involves elevated reactivity to emotions. This study tests that idea, examining self-reported reactivity. Design Comparison between persons with at least one lifetime episode of major depressive disorder (lifetime MDD) and those without this diagnosis, controlling for symptoms of alcohol use (a potential externalizing confound) and current symptoms of depression (a potential state-dependent confound). Methods Undergraduates (N = 120) completed a clinical interview to diagnose lifetime MDD and a series of self-reports bearing on diverse aspects of self-control, including reactivity to emotion. Thirty-four were diagnosed with lifetime MDD; 86 did not meet criteria for MDD. The groups were then compared on three factors underlying the scales assessing self-control. Results The MDD group had higher scores than controls on the two factors that reflect impulsive reactivity to diverse emotions, including emotions that are positive in valence. These effects were not explained by associations with either externalizing symptoms or current depressive symptoms. Conclusions Reflexive reactivity to emotions characterizes depression, in addition to some externalizing problems, and it may deserve study as a potential transdiagnostic feature. PMID:23865405

Respiratory sinus arrhythmia reactivity to a sad film predicts depression symptom improvement and symptomatic trajectory

PubMed Central

Panaite, Vanessa; Hindash, Alexandra Cowden; Bylsma, Lauren M.; Small, Brent J.; Salomon, Kristen; Rottenberg, Jonathan

2015-01-01

Respiratory sinus arrhythmia (RSA) reactivity, an index of cardiac vagal tone, has been linked to self-regulation and the severity and course of depression (Rottenberg, 2007). Although initial data supports the proposition that RSA withdrawal during a sad film is a specific predictor of depression course (Fraguas, 2007; Rottenberg, 2005), the robustness and specificity of this finding are unclear. To provide a stronger test, RSA reactivity to three emotion films (happy, sad, fear) and to a more robust stressor, a speech task, were examined in currently depressed individuals (n = 37), who were assessed for their degree of symptomatic improvement over 30 weeks. Robust RSA reactivity to the sad film uniquely predicted overall symptom improvement over 30 weeks. RSA reactivity to both sad and stressful stimuli predicted the speed and maintenance of symptomatic improvement. The current analyses provide the most robust support to date that RSA withdrawal to sad stimuli (but not stressful) has specificity in predicting the overall symptomatic improvement. In contrast, RSA reactivity to negative stimuli (both sad and stressful) predicted the trajectory of depression course. Patients’ engagement with sad stimuli may be an important sign to attend to in therapeutic settings. PMID:26681648

Atmospheric pressure resistive barrier air plasma jet induced bacterial inactivation in aqueous environment

NASA Astrophysics Data System (ADS)

Thiyagarajan, Magesh; Sarani, Abdollah; Gonzales, Xavier

2013-03-01

An atmospheric pressure resistive barrier air plasma jet is designed to inactivate bacteria in aqueous media in direct and indirect exposure modes of treatment. The resistive barrier plasma jet is designed to operate at both dc and standard 50-60 Hz low frequency ac power input and the ambient air at 50% humidity level was used as the operating gas. The voltage-current characteristics of the plasma jet were analyzed and the operating frequency of the discharge was measured to be 20 kHz and the plasma power was measured to be 26 W. The plasma jet rotational temperatures (Trot) are obtained from the optical emission spectra, from the N2C-B(2+) transitions by matching the experimental spectrum results with the Spectra Air (SPECAIR) simulation spectra. The reactive oxygen and nitrogen species were measured using optical emission spectroscopy and gas analyzers, for direct and indirect treatment modes. The nitric oxides (NO) were observed to be the predominant long lived reactive nitrogen species produced by the plasma. Three different bacteria including Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative), and Neisseria meningitidis (Gram-negative) were suspended in an aqueous media and treated by the resistive barrier air plasma jet in direct and indirect exposure modes. The results show that a near complete bacterial inactivation was achieved within 120 s for both direct and indirect plasma treatment of S. aureus and E. coli bacteria. Conversely, a partial inactivation of N. meningitidis was observed by 120 s direct plasma exposure and insignificant inactivation was observed for the indirect plasma exposure treatment. Plasma induced shifts in N. meningitidis gene expression was analyzed using pilC gene expression as a representative gene and the results showed a reduction in the expression of the pilC gene compared to untreated samples suggesting that the observed protection against NO may be regulated by other genes.

Pyrimidine Nucleobase Radical Reactivity in DNA and RNA.

PubMed

Greenberg, Marc M

2016-11-01

Nucleobase radicals are major products of the reactions between nucleic acids and hydroxyl radical, which is produced via the indirect effect of ionizing radiation. The nucleobase radicals also result from hydration of cation radicals that are produced via the direct effect of ionizing radiation. The role that nucleobase radicals play in strand scission has been investigated indirectly using ionizing radiation to generate them. More recently, the reactivity of nucleobase radicals resulting from formal hydrogen atom or hydroxyl radical addition to pyrimidines has been studied by independently generating the reactive intermediates via UV-photolysis of synthetic precursors. This approach has provided control over where the reactive intermediates are produced within biopolymers and facilitated studying their reactivity. The contributions to our understanding of pyrimidine nucleobase radical reactivity by this approach are summarized.

Pyrimidine nucleobase radical reactivity in DNA and RNA

NASA Astrophysics Data System (ADS)

Greenberg, Marc M.

2016-11-01

Nucleobase radicals are major products of the reactions between nucleic acids and hydroxyl radical, which is produced via the indirect effect of ionizing radiation. The nucleobase radicals also result from hydration of cation radicals that are produced via the direct effect of ionizing radiation. The role that nucleobase radicals play in strand scission has been investigated indirectly using ionizing radiation to generate them. More recently, the reactivity of nucleobase radicals resulting from formal hydrogen atom or hydroxyl radical addition to pyrimidines has been studied by independently generating the reactive intermediates via UV-photolysis of synthetic precursors. This approach has provided control over where the reactive intermediates are produced within biopolymers and facilitated studying their reactivity. The contributions to our understanding of pyrimidine nucleobase radical reactivity by this approach are summarized.

A model-based economic analysis of pre-pandemic influenza vaccination cost-effectiveness.

PubMed

Halder, Nilimesh; Kelso, Joel K; Milne, George J

2014-05-16

A vaccine matched to a newly emerged pandemic influenza virus would require a production time of at least 6 months with current proven techniques, and so could only be used reactively after the peak of the pandemic. A pre-pandemic vaccine, although probably having lower efficacy, could be produced and used pre-emptively. While several previous studies have investigated the cost effectiveness of pre-emptive vaccination strategies, they have not been directly compared to realistic reactive vaccination strategies. An individual-based simulation model of ~30,000 people was used to examine a pre-emptive vaccination strategy, assuming vaccination conducted prior to a pandemic using a low-efficacy vaccine. A reactive vaccination strategy, assuming a 6-month delay between pandemic emergence and availability of a high-efficacy vaccine, was also modelled. Social distancing and antiviral interventions were examined in combination with these alternative vaccination strategies. Moderate and severe pandemics were examined, based on estimates of transmissibility and clinical severity of the 1957 and 1918 pandemics respectively, and the cost effectiveness of each strategy was evaluated. Provided that a pre-pandemic vaccine achieved at least 30% efficacy, pre-emptive vaccination strategies were found to be more cost effective when compared to reactive vaccination strategies. Reactive vaccination coupled with sustained social distancing and antiviral interventions was found to be as effective at saving lives as pre-emptive vaccination coupled with limited duration social distancing and antiviral use, with both strategies saving approximately 420 life-years per 10,000 population for a moderate pandemic with a basic reproduction number of 1.9 and case fatality rate of 0.25%. Reactive vaccination was however more costly due to larger productivity losses incurred by sustained social distancing, costing $8 million per 10,000 population ($19,074/LYS) versus $6.8 million per 10,000 population ($15,897/LYS) for a pre-emptive vaccination strategy. Similar trends were observed for severe pandemics. Compared to reactive vaccination, pre-emptive strategies would be more effective and more cost effective, conditional on the pre-pandemic vaccine being able to achieve a certain level of coverage and efficacy. Reactive vaccination strategies exist which are as effective at mortality reduction as pre-emptive strategies, though they are less cost effective.

A model-based economic analysis of pre-pandemic influenza vaccination cost-effectiveness

PubMed Central

2014-01-01

Background A vaccine matched to a newly emerged pandemic influenza virus would require a production time of at least 6 months with current proven techniques, and so could only be used reactively after the peak of the pandemic. A pre-pandemic vaccine, although probably having lower efficacy, could be produced and used pre-emptively. While several previous studies have investigated the cost effectiveness of pre-emptive vaccination strategies, they have not been directly compared to realistic reactive vaccination strategies. Methods An individual-based simulation model of ~30,000 people was used to examine a pre-emptive vaccination strategy, assuming vaccination conducted prior to a pandemic using a low-efficacy vaccine. A reactive vaccination strategy, assuming a 6-month delay between pandemic emergence and availability of a high-efficacy vaccine, was also modelled. Social distancing and antiviral interventions were examined in combination with these alternative vaccination strategies. Moderate and severe pandemics were examined, based on estimates of transmissibility and clinical severity of the 1957 and 1918 pandemics respectively, and the cost effectiveness of each strategy was evaluated. Results Provided that a pre-pandemic vaccine achieved at least 30% efficacy, pre-emptive vaccination strategies were found to be more cost effective when compared to reactive vaccination strategies. Reactive vaccination coupled with sustained social distancing and antiviral interventions was found to be as effective at saving lives as pre-emptive vaccination coupled with limited duration social distancing and antiviral use, with both strategies saving approximately 420 life-years per 10,000 population for a moderate pandemic with a basic reproduction number of 1.9 and case fatality rate of 0.25%. Reactive vaccination was however more costly due to larger productivity losses incurred by sustained social distancing, costing $8 million per 10,000 population ($19,074/LYS) versus $6.8 million per 10,000 population ($15,897/LYS) for a pre-emptive vaccination strategy. Similar trends were observed for severe pandemics. Conclusions Compared to reactive vaccination, pre-emptive strategies would be more effective and more cost effective, conditional on the pre-pandemic vaccine being able to achieve a certain level of coverage and efficacy. Reactive vaccination strategies exist which are as effective at mortality reduction as pre-emptive strategies, though they are less cost effective. PMID:24884470

Unified Behavior Framework for Discrete Event Simulation Systems

DTIC Science & Technology

2015-03-26

I would like to thank Dr. Hodson for his guidance and direction throughout the AFIT program. I also would like to thank my thesis committee members...SPA Sense-Plan-Act SSL System Service Layer TCA Task Control Architecture TRP Teleo-Reactive Program UAV Unmanned Aerial Vehicle UBF Unified Behavior...a teleo-reactive architecture [11]. Teleo-Reactive Programs ( TRPs ) are composed of a list of rules, where each has a condition and an action. When the

Spectroscopic investigation and direct comparison of the reactivities of iron pyridyl oxidation catalysts

NASA Astrophysics Data System (ADS)

Song, Yang; Mayes, Howard G.; Queensen, Matthew J.; Bauer, Eike B.; Dupureur, Cynthia M.

2017-03-01

The growing interest in green chemistry has fueled attention to the development and characterization of effective iron complex oxidation catalysts. A number of iron complexes are known to catalyze the oxidation of organic substrates utilizing peroxides as the oxidant. Their development is complicated by a lack of direct comparison of the reactivities of the iron complexes. To begin to correlate reactivity with structural elements, we compare the reactivities of a series of iron pyridyl complexes toward a single dye substrate, malachite green (MG), for which colorless oxidation products are established. Complexes with tetradentate, nitrogen-based ligands with cis open coordination sites were found to be the most reactive. While some complexes reflect sensitivity to different peroxides, others are similarly reactive with either H2O2 or tBuOOH, which suggests some mechanistic distinctions. [Fe(S,S-PDP)(CH3CN)2](SbF6)2 and [Fe(OTf)2(tpa)] transition under the oxidative reaction conditions to a single intermediate at a rate that exceeds dye degradation (PDP = bis(pyridin-2-ylmethyl) bipyrrolidine; tpa = tris(2-pyridylmethyl)amine). For the less reactive [Fe(OTf)2(dpa)] (dpa = dipicolylamine), this reaction occurs on a timescale similar to that of MG oxidation. Thus, the spectroscopic method presented herein provides information about the efficiency and mechanism of iron catalyzed oxidation reactions as well as about potential oxidative catalyst decomposition and chemical changes of the catalyst before or during the oxidation reaction.

Fire and explosion hazards related to the industrial use of potassium and sodium methoxides.

PubMed

Kwok, Q; Acheson, B; Turcotte, R; Janès, A; Marlair, G

2013-04-15

Sodium and potassium methoxides are used as an intermediary for a variety of products in several industrial applications. For example, current production of so called "1G-biodiesel" relies on processing a catalytic reaction called "transesterification". This reaction transforms lipid resources from biomass materials into fatty acid methyl and ethyl esters. 1-G biodiesel processes imply the use of methanol, caustic potash (KOH), and caustic soda (NaOH) for which the hazards are well characterized. The more recent introduction of the direct catalysts CH3OK and CH3ONa may potentially introduce new process hazards. From an examination of existing MSDSs concerning these products, it appears that no consensus currently exists on their intrinsic hazardous properties. Recently, l'Institut National de l'Environnement Industriel et des Risques (France) and the Canadian Explosives Research Laboratory (Canada) have embarked upon a joint effort to better characterize the thermal hazards associated with these catalysts. This work employs the more conventional tests for water reactivity as an ignition source, fire and dust explosion hazards, using isothermal nano-calorimetry, isothermal basket tests, the Fire Propagation Apparatus and a standard 20 L sphere, respectively. It was found that these chemicals can become self-reactive close to room temperature under specific conditions and can generate explosible dusts. Copyright © 2013 Crown. Published by Elsevier B.V. All rights reserved.

Old dog begging for new tricks – Current practices and future directions in the diagnosis of delayed antimicrobial hypersensitivity

PubMed Central

Konvinse, KC; Phillips, E; White, KD; Trubiano, JA

2016-01-01

Purpose of review Antimicrobials are a leading cause of severe T-cell-mediated adverse drug reactions (ADRs). The purpose of this review is to address the current understanding of antimicrobial cross-reactivity and the ready availability of and evidence for in vitro, in vivo and ex vivo diagnostics for T-cell-mediated ADRs. Recent findings Recent literature has evaluated the efficacy of traditional antibiotic allergy management including patch testing, skin prick testing, intradermal testing and oral challenge. While patch and intradermal testing are specific for the diagnosis of immune-mediated (IM) ADRs, they suffer from drug-specific limitations in sensitivity. The use of ex vivo diagnostics, especially ELISpot has been highlighted as a promising new approach to assigning causality. Knowledge of true rates of antimicrobial cross-reactivity aids empirical antibiotic choice in the setting of previous IM-ADRs. Summary In an era of increasing antimicrobial resistance and use of broad-spectrum antimicrobial therapy, ensuring patients are assigned the correct “allergy label” is essential. Re-exposure to implicated antimicrobials, especially in the setting of severe adverse cutaneous reaction is associated with significant morbidity and mortality. The process through which an antibiotic label gets assigned, acted on and maintained is still imprecise. Predicting T-cell-mediated ADRs via personalised approaches, including HLA-typing may pave future pathways to safer antimicrobial prescribing guidelines. PMID:27753687

A dc non-thermal atmospheric-pressure plasma microjet

NASA Astrophysics Data System (ADS)

Zhu, WeiDong; Lopez, Jose L.

2012-06-01

A direct current (dc), non-thermal, atmospheric-pressure plasma microjet is generated with helium/oxygen gas mixture as working gas. The electrical property is characterized as a function of the oxygen concentration and show distinctive regions of operation. Side-on images of the jet were taken to analyze the mode of operation as well as the jet length. A self-pulsed mode is observed before the transition of the discharge to normal glow mode. Optical emission spectroscopy is employed from both end-on and side-on along the jet to analyze the reactive species generated in the plasma. Line emissions from atomic oxygen (at 777.4 nm) and helium (at 706.5 nm) were studied with respect to the oxygen volume percentage in the working gas, flow rate and discharge current. Optical emission intensities of Cu and OH are found to depend heavily on the oxygen concentration in the working gas. Ozone concentration measured in a semi-confined zone in front of the plasma jet is found to be from tens to ˜120 ppm. The results presented here demonstrate potential pathways for the adjustment and tuning of various plasma parameters such as reactive species selectivity and quantities or even ultraviolet emission intensities manipulation in an atmospheric-pressure non-thermal plasma source. The possibilities of fine tuning these plasma species allows for enhanced applications in health and medical related areas.

Reactive Nitrogen in Atmospheric Emission Inventories

EPA Science Inventory

Excess reactive Nitrogen (NT) has become one of the most pressing environmental problems leading to air pollution, acidification and eutrophication of ecosystems, biodiversity impacts, leaching of nitrates into groundwater and global warming. This paper investigates how current i...

Skin sensitisation: the Colipa strategy for developing and evaluating non-animal test methods for risk assessment.

PubMed

Maxwell, Gavin; Aeby, Pierre; Ashikaga, Takao; Bessou-Touya, Sandrine; Diembeck, Walter; Gerberick, Frank; Kern, Petra; Marrec-Fairley, Monique; Ovigne, Jean-Marc; Sakaguchi, Hitoshi; Schroeder, Klaus; Tailhardat, Magali; Teissier, Silvia; Winkler, Petra

2011-01-01

Allergic contact dermatitis is a delayed-type hypersensitivity reaction induced by small reactive chemicals (haptens). Currently, the sensitising potential and potency of new chemicals is usually characterised using data generated via animal studies, such as the local lymph node assay (LLNA). There are, however, increasing public and political concerns regarding the use of animals for the testing of new chemicals. Consequently, the development of in vitro, in chemico or in silico models for predicting the sensitising potential and/or potency of new chemicals is receiving widespread interest. The Colipa Skin Tolerance task force currently collaborates with and/or funds several academic research groups to expand our understanding of the molecular and cellular events occurring during the acquisition of skin sensitisation. Knowledge gained from this research is being used to support the development and evaluation of novel alternative approaches for the identification and characterisation of skin sensitizing chemicals. At present three non-animal test methods (Direct Peptide Reactivity Assay (DPRA), Myeloid U937 Skin Sensitisation Test (MUSST) and human Cell Line Activation Test (hCLAT)) have been evaluated in Colipa interlaboratory ring trials for their potential to predict skin sensitisation potential and were recently submitted to ECVAM for formal pre-validation. Data from all three test methods will now be used to support the study and development of testing strategy approaches for skin sensitiser potency prediction. This publication represents the current viewpoint of the cosmetics industry on the feasibility of replacing the need for animal test data for informing skin sensitisation risk assessment decisions.

Caregiver Protective Behavior, Toddler Fear and Sadness, and Toddler Cortisol Reactivity in Novel Contexts

PubMed Central

Hutt, Rachel L.; Buss, Kristin A.; Kiel, Elizabeth J.

2012-01-01

Previous research has shown that caregiver protective behavior may exacerbate toddler distress in specific contexts. The current study sought to extend this work to examine associations between these variables and toddler cortisol reactivity. Ninety-three 24-month-old toddlers were observed across six novel contexts designed to elicit distress. Toddlers were asked to give saliva samples at the beginning and end of the laboratory procedure. Toddler sadness, toddler fear, and caregiver protective behavior were coded. Results indicate that caregiver protective behavior accounted for the association between toddler sadness and cortisol reactivity where higher levels of protective behavior were associated with higher cortisol reactivity. The current study showed that caregiver protective behavior, which functions to prevent a child from interacting with a novel stimulus, is an important mechanism to consider when understanding toddler stress responses during novel contexts. PMID:24659922

Evidence that the reactivity of the martian soil is due to superoxide ions

NASA Technical Reports Server (NTRS)

Yen, A. S.; Kim, S. S.; Hecht, M. H.; Frant, M. S.; Murray, B.

2000-01-01

The Viking Landers were unable to detect evidence of life on Mars but, instead, found a chemically reactive soil capable of decomposing organic molecules. This reactivity was attributed to the presence of one or more as-yet-unidentified inorganic superoxides or peroxides in the martian soil. Using electron paramagnetic resonance spectroscopy, we show that superoxide radical ions (O2-) form directly on Mars-analog mineral surfaces exposed to ultraviolet radiation under a simulated martian atmosphere. These oxygen radicals can explain the reactive nature of the soil and the apparent absence of organic material at the martian surface.

Matrix effect and cross-reactivity of select amphetamine-type substances, designer analogues, and putrefactive amines using the Bio-Quant direct ELISA presumptive assays for amphetamine and methamphetamine.

PubMed

Apollonio, Luigino G; Whittall, Ian R; Pianca, Dennis J; Kyd, Jennelle M; Maher, William A

2007-05-01

The aim of this study was to evaluate the Bio-Quant Direct ELISA assays for amphetamine and methamphetamine in the routine presumptive screening of biological fluids. Standard concentration curves of the target analytes were assayed to assess sensitivity, and known concentrations of common amphetamine-type substances (ephedrine, pseudoephedrine, phentermine), designer analogues (MDA, MDMA, MDEA, MBDB, PMA, 4-MTA, 2CB), and putrefactive amines (phenylethylamine, putrescine, tryptamine, tyramine) were analyzed to determine cross-reactivity. Results of the standard curve studies show the capacity of both Direct ELISA kits to confidently detect down to 3 ng/mL interday (PBS matrix; CVs 6.3-15.5%). Cross-reactivity relative to that of 50 ng/mL preparations of the target compounds demonstrated that the Direct ELISA kit for amphetamine also detected MDA (282%), PMA (265%), 4-MTA (280%), and phentermine (61%), and the Direct ELISA for methamphetamine also assayed positive for MDMA (73%), MDEA (18%), pseudoephedrine (19%), MBDB (8%), and ephedrine (9%). Matrix studies demonstrated that both ELISA kits could be applied to screening of blood, urine, and saliva to a concentration of 6 ng/mL or lower. In conclusion, the Bio-Quant Direct ELISA kits for amphetamine and methamphetamine are fast and accurate and have demonstrated themselves to be useful tools in routine toxicological testing.

Land and Land-use Change in the Climate Sensitive High Plains: An Automated Approach with Landsat

NASA Technical Reports Server (NTRS)

Goetz, Alexander F.; Williams, D. L. (Technical Monitor)

2002-01-01

The High Plains is an economically important and climatologically sensitive region of the United States and Canada. The High Plains contain 100,000 sq km of Holocene sand dunes and sand sheets that are currently stabilized by natural vegetation. Droughts and the larger threat of global warming are climate phenomena that could cause depletion of natural vegetation and make this region susceptible to sand dune reactivation. The original proposal was directed toward the use of Landsat TM data to establish the state and ongoing changes of the surface in the 1.2 million sq. km, semi-arid High Plains region of the central US, A key objective was to develop a model to predict the reactivation of the 100,000 sq. km of Holocene dunes found on the High Plains during an extended drought. At least one Landsat 5 image per year for 1985, 1988 and 1996 was obtained for 32 scenes on the High Plains to coincide with wet and dry years. Additional Landsat 7 data were acquired for 1999 and 2000 primarily for Colorado and Nebraska. As luck would have it, there was no severe drought during the study period 1985-2000. Attention was focused on developing methods for mapping dry vs. green vegetation on sparsely vegetated rangelands in sandy soils, since these were the areas most susceptible to surface reactivation during a drought.

Preclinical Testing of Antihuman CD28 Fab' Antibody in a Novel Nonhuman Primate Small Animal Rodent Model of Xenogenic Graft-Versus-Host Disease.

PubMed

Hippen, Keli L; Watkins, Benjamin; Tkachev, Victor; Lemire, Amanda M; Lehnen, Charles; Riddle, Megan J; Singh, Karnail; Panoskaltsis-Mortari, Angela; Vanhove, Bernard; Tolar, Jakub; Kean, Leslie S; Blazar, Bruce R

2016-12-01

Graft-versus-host disease (GVHD) is a severe complication of hematopoietic stem cell transplantation. Current therapies to prevent alloreactive T cell activation largely cause generalized immunosuppression and may result in adverse drug, antileukemia and antipathogen responses. Recently, several immunomodulatory therapeutics have been developed that show efficacy in maintaining antileukemia responses while inhibiting GVHD in murine models. To analyze efficacy and better understand immunological tolerance, escape mechanisms, and side effects of clinical reagents, testing of species cross-reactive human agents in large animal GVHD models is critical. We have previously developed and refined a nonhuman primate (NHP) large animal GVHD model. However, this model is not readily amenable to semi-high throughput screening of candidate clinical reagents. Here, we report a novel, optimized NHP xenogeneic GVHD (xeno-GVHD) small animal model that recapitulates many aspects of NHP and human GVHD. This model was validated using a clinically available blocking, monovalent anti-CD28 antibody (FR104) whose effects in a human xeno-GVHD rodent model are known. Because human-reactive reagents may not be fully cross-reactive or effective in vivo on NHP immune cells, this NHP xeno-GVHD model provides immunological insights and direct testing on NHP-induced GVHD before committing to the intensive NHP studies that are being increasingly used for detailed evaluation of new immune therapeutic strategies before human trials.

Isolating the effects of reactivity stratification in reactivity-controlled compression ignition with iso-octane and n-heptane on a light-duty multi-cylinder engine

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

Wissink, Martin L.; Curran, Scott J.; Roberts, Greg

Reactivity-controlled compression ignition (RCCI) is a dual-fuel variant of low-temperature combustion that uses in-cylinder fuel stratification to control the rate of reactions occurring during combustion. Using fuels of varying reactivity (autoignition propensity), gradients of reactivity can be established within the charge, allowing for control over combustion phasing and duration for high efficiency while achieving low NO x and soot emissions. In practice, this is typically accomplished by premixing a low-reactivity fuel, such as gasoline, with early port or direct injection, and by direct injecting a high-reactivity fuel, such as diesel, at an intermediate timing before top dead center. Both themore » relative quantity and the timing of the injection(s) of high-reactivity fuel can be used to tailor the combustion process and thereby the efficiency and emissions under RCCI. While many combinations of high- and low-reactivity fuels have been successfully demonstrated to enable RCCI, there is a lack of fundamental understanding of what properties, chemical or physical, are most important or desirable for extending operation to both lower and higher loads and reducing emissions of unreacted fuel and CO. This is partly due to the fact that important variables such as temperature, equivalence ratio, and reactivity change simultaneously in both a local and a global sense with changes in the injection of the high-reactivity fuel. This study uses primary reference fuels iso-octane and n-heptane, which have similar physical properties but much different autoignition properties, to create both external and in-cylinder fuel blends that allow for the effects of reactivity stratification to be isolated and quantified. This study is part of a collaborative effort with researchers at Sandia National Laboratories who are investigating the same fuels and conditions of interest in an optical engine. Furthermore, this collaboration aims to improve our fundamental understanding of what fuel properties are required to further develop advanced combustion modes.« less

Isolating the effects of reactivity stratification in reactivity-controlled compression ignition with iso-octane and n-heptane on a light-duty multi-cylinder engine

DOE PAGES

Wissink, Martin L.; Curran, Scott J.; Roberts, Greg; ...

2017-10-09

Reactivity-controlled compression ignition (RCCI) is a dual-fuel variant of low-temperature combustion that uses in-cylinder fuel stratification to control the rate of reactions occurring during combustion. Using fuels of varying reactivity (autoignition propensity), gradients of reactivity can be established within the charge, allowing for control over combustion phasing and duration for high efficiency while achieving low NO x and soot emissions. In practice, this is typically accomplished by premixing a low-reactivity fuel, such as gasoline, with early port or direct injection, and by direct injecting a high-reactivity fuel, such as diesel, at an intermediate timing before top dead center. Both themore » relative quantity and the timing of the injection(s) of high-reactivity fuel can be used to tailor the combustion process and thereby the efficiency and emissions under RCCI. While many combinations of high- and low-reactivity fuels have been successfully demonstrated to enable RCCI, there is a lack of fundamental understanding of what properties, chemical or physical, are most important or desirable for extending operation to both lower and higher loads and reducing emissions of unreacted fuel and CO. This is partly due to the fact that important variables such as temperature, equivalence ratio, and reactivity change simultaneously in both a local and a global sense with changes in the injection of the high-reactivity fuel. This study uses primary reference fuels iso-octane and n-heptane, which have similar physical properties but much different autoignition properties, to create both external and in-cylinder fuel blends that allow for the effects of reactivity stratification to be isolated and quantified. This study is part of a collaborative effort with researchers at Sandia National Laboratories who are investigating the same fuels and conditions of interest in an optical engine. Furthermore, this collaboration aims to improve our fundamental understanding of what fuel properties are required to further develop advanced combustion modes.« less

Measuring Sensory Reactivity in Autism Spectrum Disorder: Application and Simplification of a Clinician-Administered Sensory Observation Scale

ERIC Educational Resources Information Center

Tavassoli, Teresa; Bellesheim, Katherine; Siper, Paige M.; Wang, A. Ting; Halpern, Danielle; Gorenstein, Michelle; Grodberg, David; Kolevzon, Alexander; Buxbaum, Joseph D.

2016-01-01

Sensory reactivity is a new DSM-5 criterion for autism spectrum disorder (ASD). The current study aims to validate a clinician-administered sensory observation in ASD, the Sensory Processing Scale Assessment (SPS). The SPS and the Short Sensory Profile (SSP) parent-report were used to measure sensory reactivity in children with ASD (n = 35) and…

Risk of hepatitis B virus reactivation with direct-acting antivirals against hepatitis C virus: A cohort study from Egypt and meta-analysis of published data.

PubMed

El Kassas, Mohamed; Shimakawa, Yusuke; Ali-Eldin, Zainab; Funk, Anna-Louise; Wifi, Mohamed Naguib; Zaky, Samy; El-Raey, Fathiya; Esmat, Gamal; Fontanet, Arnaud

2018-05-08

Hepatitis B virus (HBV) reactivation in chronic hepatitis C (CHC) patients treated with direct-acting antivirals (DAAs) became an issue. However, its frequency has been poorly estimated, because of the varying definitions used and evaluation of heterogeneous study populations, including those concurrently treated for HBV. We prospectively followed HBV surface antigen (HBsAg)-positive Egyptians undergoing interferon-free DAAs, to estimate the risk of HBV reactivation and HBV-related hepatitis. We also conducted a meta-analysis to estimate the reactivation risk using published data obtained from a systematic review of PubMed/Embase, in addition to our Egyptian data. We applied a standard definition of HBV reactivation proposed by the international liver associations (APASL and AASLD). Of 4471 CHC patients, 35 HBsAg-positive patients started interferon-free DAAs without HBV nucleos(t)ide analogues in our Egyptian cohort. Ten experienced HBV reactivation (28.6%), of whom 1 developed hepatitis (10.0%). Our systematic review identified 18 papers. The pooled reactivation risk in HBsAg-positive patients was 18.2% (95% CI: 7.9%-30.7%) without HBV therapy and 0.0% (95% CI: 0.0%-0.0%) with HBV nucleos(t)ide analogue. The pooled risk of hepatitis in those with HBV reactivation was 12.6% (95% CI: 0.0%-34.7%). The pooled reactivation risk in HBsAg-negative, antibody to HBV core antigen-positive (anti-HBc-positive) patients was negligible (0.1%, 95% CI: 0.0%-0.3%), irrespective of the presence of antibody to HBsAg (anti-HBs). We confirmed high HBV reactivation risk in HBsAg-positive patients undergoing DAAs, with only a minority developing clinically important hepatitis. The risk is negligible for HBsAg-negative anti-HBc-positive patients. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Analysis of the Association Between Motor and Anthropometric Variables with Change of Direction Speed and Reactive Agility Performance

PubMed Central

Sattler, Tine; Sekulić, Damir; Spasić, Miodrag; Perić, Mia; Krolo, Ante; Uljević, Ognjen; Kondrič, Miran

2015-01-01

There is an evident lack of studies examining the factors associated with reactive agility performances. The aim of this study was to evaluate the association between anthropometrics, body composition, jumping capacity, reactive strength, and balance with a stop-and-go change of direction speed (CODS) and reactive agility. The total sample comprised 39 male (body height: 182.95 ± 5.19 cm; body mass: 80.66 ± 7.69 kg) and 34 female (body height: 171.45 ± 6.81 cm; body mass: 61.95 ± 6.70 kg) college-level athletes (21.9 ± 1.9 years of age). The variables included body height, body mass, the percentage of body fat (BF%), balance as measured by an overall-stability index, the countermovement jump (CMJ), a reactive-strength index (RSI), stop-and-go reactive agility, and stop-and-go CODS. To define the associations between motor and anthropometric variables with CODS and reactive agility, the participants were clustered into three achievement groups based on their CODS and reactive agility performances. The ANOVA showed a significant difference between the CODS-based achievement groups for the CMJ (F test = 3.45 and 3.60 for males and females, respectively; p < 0.05), the RSI (F test = 6.94 and 5.29 for males and females, respectively; p < 0.05), and balance (F test = 3.47; p < 0.05 for males). In females, the reactive agility achievement groups differed significantly in the RSI (F test = 6.46; p < 0.05), the CMJ (F test = 4.35; p < 0.05) and BF% (F test = 4.07; p < 0.05), which is further confirmed by discriminant canonical analysis (Can R = 0.74; p < 0.05). The results confirm the need for independent evaluation and training for both CODS and reactive agility performance in sports. PMID:26557198

Developmental origins of chronic inflammation: a review of the relationship between birth weight and C-reactive protein.

PubMed

deRosset, Leslie; Strutz, Kelly L

2015-07-01

The developmental origins of adult disease hypothesis suggests that the intrauterine environment may program postnatal health outcomes through mechanisms such as chronic inflammation. The purpose of this article was to review the literature on the association between infant birth weight and C-reactive protein (CRP), markers of the fetal environment and inflammation, respectively. We used PubMed, Google Scholar, Web of Science, ScienceDirect, the citation lists of the reviewed literature, and recommendations from experts in the field to identify potential articles. Inclusion criteria for the studies, regardless of study design, included human subjects, documented or self-reported infant birth weight, and a minimum of one measurement of CRP (during childhood, adolescence, or adulthood). Several studies demonstrated a statistically significant inverse association between birth weight and CRP in adulthood, although in many cases only after controlling for markers of current adiposity. No studies significantly linked birth weight to CRP in childhood or adolescence. Longitudinal studies, including multigenerational studies, are needed to further understand whether adult CRP has origins in the fetal environment. Copyright © 2015 Elsevier Inc. All rights reserved.

The Potential Roles of Bisphenol A (BPA) Pathogenesis in Autoimmunity

PubMed Central

2014-01-01

Bisphenol A (BPA) is a monomer found in commonly used consumer plastic goods. Although much attention in recent years has been placed on BPA's impact as an endocrine disruptor, it also appears to activate many immune pathways involved in both autoimmune disease development and autoimmune reactivity provocation. The current scientific literature is void of research papers linking BPA directly to human or animal onset of autoimmunity. This paper explores the impact of BPA on immune reactivity and the potential roles these mechanisms may have on the development or provocation of autoimmune diseases. Potential mechanisms by which BPA may be a contributing risk factor to autoimmune disease development and progression include its impact on hyperprolactinemia, estrogenic immune signaling, cytochrome P450 enzyme disruption, immune signal transduction pathway alteration, cytokine polarization, aryl hydrocarbon activation of Th-17 receptors, molecular mimicry, macrophage activation, lipopolysaccharide activation, and immunoglobulin pathophysiology. In this paper a review of these known autoimmune triggering mechanisms will be correlated with BPA exposure, thereby suggesting that BPA has a role in the pathogenesis of autoimmunity. PMID:24804084

Comparative study of ITO and TiN fabricated by low-temperature RF biased sputtering

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

Simon, Daniel K., E-mail: daniel.simon@namlab.com; Schenk, Tony; Dirnstorfer, Ingo

2016-03-15

Radio frequency (RF) biasing induced by a second plasma source at the substrate is applied to low-temperature sputtering processes for indium tin oxide (ITO) and titanium nitride (TiN) thin films. Investigations on crystal structure and surface morphology show that RF-biased substrate plasma processes result in a changed growth regime with different grain sizes and orientations than those produced by processes without a substrate bias. The influence of the RF bias is shown comparatively for reactive RF-sputtered ITO and reactive direct-current-sputtered TiN. The ITO layers exhibit an improved electrical resistivity of 0.5 mΩ cm and an optical absorption coefficient of 0.5 × 10{sup 4 }cm{supmore » −1} without substrate heating. Room-temperature sputtered TiN layers are deposited that possess a resistivity (0.1 mΩ cm) of 3 orders of magnitude lower than, and a density (5.4 g/cm{sup 3}) up to 45% greater than, those obtained from layers grown using the standard process without a substrate plasma.« less

Synovial fluid cytology in experimental acute canine monocytic ehrlichiosis (Ehrlichia canis).

PubMed

Theodorou, Konstantina; Leontides, Leonidas; Siarkou, Victoria I; Petanides, Theodoros; Tsafas, Konstantinos; Harrus, Shimon; Mylonakis, Mathios E

2015-05-15

Evidence-based information of a cause-and-effect relationship between Ehrlichia canis infection and polyarthritis in naturally- or experimentally-infected dogs is currently lacking. The aim of this prospective study was to investigate whether synovial fluid cytological evidence of arthritis could be documented in dogs with acute monocytic ehrlichiosis. Direct synovial fluid cytology smears from eight Beagle dogs experimentally infected with E. canis were examined prior to, and on 21, 35 and 63 days post-inoculation. The cytological variables assessed included cellularity, percentages of mononuclear cells and neutrophils, macrophage reactivity and evidence of E. canis morulae. The median cellularity and percentages of mononuclear cells and neutrophils prior to inoculation did not differ when compared to post-inoculation cytological evaluation. Increased cellularity, E. canis morulae or cytological evidence of arthritis or macrophage reactivity were not observed throughout the course of the study. In the present study, no cytological evidence of arthritis was found in dogs with experimental acute canine monocytic ehrlichiosis, suggesting that E. canis infection should be considered a rather uncommon cause of arthritis in dogs. Copyright © 2015 Elsevier B.V. All rights reserved.

9-Fluorenylmethyl (Fm) Disulfides: Biomimetic Precursors for Persulfides

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

Park, Chung-Min; Johnson, Brett A.; Duan, Jicheng

Protein S-sulfhydration has been recognized as an important post-translational modification that regulates H2S signals. However, the reactivity and biological implications of the products of S-sulfhydration, i.e. persulfides, are still unclear. This is mainly due to the instability of persulfides and difficulty to access these molecules. Under physiological conditions persulfides mainly exist in anionic forms because of their low pKa values. However, current methods do not allow for the direct generation of persulfide anions under biomimetic and non-H2S conditions. Herein we report the development of a functional disulfide, FmSSPy-A (Fm =9-fluorenylmethyl; Py = pyridinyl). This reagent can effectively convert both smallmore » molecule and protein thiols (-SH) to form –S-SFm adducts under mild conditions. It allows for a H2S-free and biomimetic protocol to generate highly reactive persulfides (in their anionic forms). We also demonstrated the high nucleophilicity of persulfides toward a number of thiol-blocking reagents. This method holds promise for further understanding the chemical biology of persulfides and S-sulfhydration.« less

Principles in redox signaling: from chemistry to functional significance.

PubMed

Bindoli, Alberto; Rigobello, Maria Pia

2013-05-01

Reactive oxygen and nitrogen species are currently considered not only harmful byproducts of aerobic respiration but also critical mediators of redox signaling. The molecules and the chemical principles sustaining the network of cellular redox regulated processes are described. Special emphasis is placed on hydrogen peroxide (H(2)O(2)), now considered as acting as a second messenger, and on sulfhydryl groups, which are the direct targets of the oxidant signal. Cysteine residues of some proteins, therefore, act as sensors of redox conditions and are oxidized in a reversible reaction. In particular, the formation of sulfenic acid and disulfide, the initial steps of thiol oxidation, are described in detail. The many cell pathways involved in reactive oxygen species formation are reported. Central to redox signaling processes are the glutathione and thioredoxin systems controlling H(2)O(2) levels and, hence, the thiol/disulfide balance. Lastly, some of the most important redox-regulated processes involving specific enzymes and organelles are described. The redox signaling area of research is rapidly expanding, and future work will examine new pathways and clarify their importance in cellular pathophysiology.

Stressful life events and depression symptoms: the effect of childhood emotional abuse on stress reactivity.

PubMed

Shapero, Benjamin G; Black, Shimrit K; Liu, Richard T; Klugman, Joshua; Bender, Rachel E; Abramson, Lyn Y; Alloy, Lauren B

2014-03-01

Stressful life events are associated with an increase in depressive symptoms and the onset of major depression. Importantly, research has shown that the role of stress changes over the course of depression. The present study extends the current literature by examining the effects of early life stress on emotional reactivity to current stressors. In a multiwave study (N = 281, mean age = 18.76; 68% female), we investigated the proximal changes that occur in depressive symptoms when individuals are faced with life stress and whether a history of childhood emotional abuse moderates this relationship. Results support the stress sensitivity hypothesis for early emotional abuse history. Individuals with greater childhood emotional abuse severity experienced greater increases in depressive symptoms when confronted with current dependent stressors, controlling for childhood physical and sexual abuse. This study highlights the importance of emotional abuse as an indicator for reactivity to stressful life events. © 2013 Wiley Periodicals, Inc.

A streamlined software environment for situated skills

NASA Technical Reports Server (NTRS)

Yu, Sophia T.; Slack, Marc G.; Miller, David P.

1994-01-01

This paper documents a powerful set of software tools used for developing situated skills. These situated skills form the reactive level of a three-tiered intelligent agent architecture. The architecture is designed to allow these skills to be manipulated by a task level engine which is monitoring the current situation and selecting skills necessary for the current task. The idea is to coordinate the dynamic activations and deactivations of these situated skills in order to configure the reactive layer for the task at hand. The heart of the skills environment is a data flow mechanism which pipelines the currently active skills for execution. A front end graphical interface serves as a debugging facility during skill development and testing. We are able to integrate skills developed in different languages into the skills environment. The power of the skills environment lies in the amount of time it saves for the programmer to develop code for the reactive layer of a robot.

High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation

NASA Astrophysics Data System (ADS)

Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

2017-08-01

Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system.

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

Usman, Yasir; Kim, Jinho; Muljadi, Eduard

Wake effects cause wind turbine generators (WTGs) within a wind power plant (WPP) to produce different levels of active power and subsequent reactive power capabilities. Further, the impedance between a WTG and the point of interconnection (POI)-which depends on the distance between them-impacts the WPP's reactive power injection capability at the POI. This paper proposes a voltage control scheme for a WPP based on the available reactive current of the doubly-fed induction generators (DFIGs) and its impacts on the POI to improve the reactive power injection capability of the WPP. In this paper, a design strategy for modifying the gainmore » of DFIG controller is suggested and the comprehensive properties of these control gains are investigated. In the proposed scheme, the WPP controller, which operates in a voltage control mode, sends the command signal to the DFIGs based on the voltage difference at the POI. The DFIG controllers, which operate in a voltage control mode, employ a proportional controller with a limiter. The gain of the proportional controller is adjusted depending on the available reactive current of the DFIG and the series impedance between the DFIG and the POI. The performance of the proposed scheme is validated for various disturbances such as a reactive load connection and grid fault using an EMTP-RV simulator. Furthermore, simulation results demonstrate that the proposed scheme promptly recovers the POI voltage by injecting more reactive power after a disturbance than the conventional scheme.« less

Major depressive disorder and impulsive reactivity to emotion: toward a dual-process view of depression.

PubMed

Carver, Charles S; Johnson, Sheri L; Joormann, Jutta

2013-09-01

Dual-process theories of behaviour have been used to suggest that vulnerability to depression involves elevated reactivity to emotions. This study tests that idea, examining self-reported reactivity. Comparison between persons with at least one lifetime episode of major depressive disorder (lifetime MDD) and those without this diagnosis, controlling for symptoms of alcohol use (a potential externalizing confound) and current symptoms of depression (a potential state-dependent confound). Undergraduates (N = 120) completed a clinical interview to diagnose lifetime MDD and a series of self-reports bearing on diverse aspects of self-control, including reactivity to emotion. Thirty-four people were diagnosed with lifetime MDD; 86 did not meet criteria for MDD. The groups were then compared on three factors underlying the scales assessing self-control. The MDD group had higher scores than controls on the two factors that reflect impulsive reactivity to diverse emotions, including emotions that are positive in valence. These effects were not explained by associations with either externalizing symptoms or current depressive symptoms. Reflexive reactivity to emotions characterizes depression, in addition to some externalizing problems, and it may deserve study as a potential trans-diagnostic feature. Reflexive reactivity to emotions characterizes persons diagnosed with major depressive disorder. Findings suggest desirability of focusing treatment partly on management of reflexive reactions to emotions. Measures were self-reports, rather than behavioural responses to emotions. © 2013 The British Psychological Society.

LONG-TERM PERFORMANCE OF PERMEABLE REACTIVE BARRIERS: LESSONS LEARNED, FUTURE DIRECTIONS

EPA Science Inventory

Recently, a synthesis of research findings by EPA has been prepared and presented in an EPA report titled Capstone Report on the Application, Monitoring, and Performance of Permeable Reactive Barriers for Ground-Water Remediation (EPA/600/R-03/045 a,b). Another report has also be...

DNA-REACTIVE CARCINOGENS: MODE OF ACTION AND HUMAN CANCER HAZARD

EPA Science Inventory

It has been known for decades that mutagenicity plays an important role in the activity of most carcinogens. This mutagenicity can result from direct damage to DNA through a chemical being DNA-reactive or from indirect effects, such as through the production of oxygen radicals th...

Validity of Evidence-Derived Criteria for Reactive Attachment Disorder: Indiscriminately Social/Disinhibited and Emotionally Withdrawn/Inhibited Types

ERIC Educational Resources Information Center

Gleason, Mary Margaret; Fox, Nathan A.; Drury, Stacy; Smyke, Anna; Egger, Helen L.; Nelson, Charles A., III; Gregas, Matthew C.; Zeanah, Charles H.

2011-01-01

Objective: This study examined the validity of criteria for indiscriminately social/disinhibited and emotionally withdrawn/inhibited reactive attachment disorder (RAD). Method: As part of a longitudinal intervention trial of previously institutionalized children, caregiver interviews and direct observational measurements provided continuous and…

Cognitive reactivity as outcome and working mechanism of mindfulness-based cognitive therapy for recurrently depressed patients in remission.

PubMed

Cladder-Micus, M B; van Aalderen, J; Donders, A R T; Spijker, J; Vrijsen, J N; Speckens, A E M

2018-03-01

Major depressive disorder is a prevalent condition with high relapse rates. There is evidence that cognitive reactivity is an important vulnerability factor for the recurrence of depression. Mindfulness-based interventions are designed to reduce relapse rates, with cognitive reactivity as one of the proposed working mechanisms. In a randomised controlled trial we compared the effect of mindfulness-based cognitive therapy (MBCT) with treatment-as-usual (TAU) on cognitive reactivity in recurrently depressed patients (N = 115). Depressive symptoms, cognitive reactivity, and mindfulness skills were assessed pre and post treatment. Patients in the MBCT group reported a significantly greater reduction in cognitive reactivity than those in the TAU group (d = .51). The reduction of cognitive reactivity appeared to mediate the association between MBCT/TAU and decrease of depressive symptoms, using pre and post scores. The current study provides evidence that MBCT reduces cognitive reactivity and preliminary evidence that cognitive reactivity is a working mechanism of MBCT.

Peer victimization (and harsh parenting) as developmental correlates of cognitive reactivity, a diathesis for depression.

PubMed

Cole, David A; Martin, Nina C; Sterba, Sonya K; Sinclair-McBride, Keneisha; Roeder, Kathryn M; Zelkowitz, Rachel; Bilsky, Sarah A

2014-05-01

Prior research has shown cognitive reactivity to be a diathesis for depression. Seeking evidence for the developmental origins of such diatheses, the current study examined peer victimization and harsh parenting as developmental correlates of cognitive reactivity in 571 children and adolescents (ages 8-13 years). Four major findings emerged. First, a new method for assessing cognitive reactivity in children and adolescents showed significant reliability and demonstrated construct validity vis-à-vis its relation to depression. Second, history of more severe peer victimization was significantly related to cognitive reactivity, with verbal victimization being more strongly tied to cognitive reactivity than other subtypes of peer victimization. Third, harsh parenting was also significantly related to cognitive reactivity. Fourth, both peer victimization and harsh parenting made unique statistical contributions to cognitive reactivity, after controlling for the effects of the other. Taken together, these findings provide preliminary support for a developmental model pertaining to origins of cognitive reactivity in children and adolescents.

Transcranial Direct Current Stimulation of the Left Dorsolateral Prefrontal Cortex Shifts Preference of Moral Judgments

PubMed Central

Kuehne, Maria; Heimrath, Kai; Heinze, Hans-Jochen; Zaehle, Tino

2015-01-01

Attitude to morality, reflecting cultural norms and values, is considered unique to human social behavior. Resulting moral behavior in a social environment is controlled by a widespread neural network including the dorsolateral prefrontal cortex (DLPFC), which plays an important role in decision making. In the present study we investigate the influence of neurophysiological modulation of DLPFC reactivity by means of transcranial direct current stimulation (tDCS) on moral reasoning. For that purpose we administered anodal, cathodal, and sham stimulation of the left DLPFC while subjects judged the appropriateness of hard moral personal dilemmas. In contrast to sham and cathodal stimulation, anodal stimulation induced a shift in judgment of personal moral dilemmas towards more non-utilitarian actions. Our results demonstrate that alterations of left DLPFC activity can change moral judgments and, in consequence, provide a causal link between left DLPFC activity and moral reasoning. Most important, the observed shift towards non-utilitarian actions suggests that moral decision making is not a permanent individual trait but can be manipulated; consequently individuals with boundless, uncontrollable, and maladaptive moral behavior, such as found in psychopathy, might benefit from neuromodulation-based approaches. PMID:25985442

Systems and methods for providing power to a load based upon a control strategy

DOEpatents

Perisic, Milun; Lawrence, Christopher P; Ransom, Ray M; Kajouke, Lateef A

2014-11-04

Systems and methods are provided for an electrical system. The electrical system, for example, includes a first load, an interface configured to receive a voltage from a voltage source, and a controller configured to receive the voltage through the interface and to provide a voltage and current to the first load. The controller may be further configured to, receive information on a second load electrically connected to the voltage source, determine an amount of reactive current to return to the voltage source such that a current drawn by the electrical system and the second load from the voltage source is substantially real, and provide the determined reactive current to the voltage source.

Respiratory sinus arrhythmia reactivity to a sad film predicts depression symptom improvement and symptomatic trajectory.

PubMed

Panaite, Vanessa; Hindash, Alexandra Cowden; Bylsma, Lauren M; Small, Brent J; Salomon, Kristen; Rottenberg, Jonathan

2016-01-01

Respiratory sinus arrhythmia (RSA) reactivity, an index of cardiac vagal tone, has been linked to self-regulation and the severity and course of depression (Rottenberg, 2007). Although initial data supports the proposition that RSA withdrawal during a sad film is a specific predictor of depression course (Fraguas, 2007; Rottenberg, 2005), the robustness and specificity of this finding are unclear. To provide a stronger test, RSA reactivity to three emotion films (happy, sad, fear) and to a more robust stressor, a speech task, were examined in currently depressed individuals (n=37), who were assessed for their degree of symptomatic improvement over 30weeks. Robust RSA reactivity to the sad film uniquely predicted overall symptom improvement over 30weeks. RSA reactivity to both sad and stressful stimuli predicted the speed and maintenance of symptomatic improvement. The current analyses provide the most robust support to date that RSA withdrawal to sad stimuli (but not stressful) has specificity in predicting the overall symptomatic improvement. In contrast, RSA reactivity to negative stimuli (both sad and stressful) predicted the trajectory of depression course. Patients' engagement with sad stimuli may be an important sign to attend to in therapeutic settings. Copyright © 2015 Elsevier B.V. All rights reserved.

Towards a rational approach for heavy-atom derivative screening in protein crystallography

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

Agniswamy, Johnson; Joyce, M. Gordon; Hammer, Carl H.

2008-04-01

Heavy-atom derivatization is routinely used in protein structure determination and is thus of critical importance in structural biology. In order to replace the current trial-and-error heavy-atom derivative screening with a knowledge-based rational derivative-selection method, the reactivity of more than 40 heavy-atom compounds over a wide range of buffer and pH values was systematically examined using peptides which contained a single reactive amino-acid residue. Heavy-atom derivatization is routinely used in protein structure determination and is thus of critical importance in structural biology. In order to replace the current trial-and-error heavy-atom derivative screening with a knowledge-based rational derivative-selection method, the reactivity ofmore » more than 40 heavy-atom compounds over a wide range of buffer and pH values was systematically examined using peptides which contained a single reactive amino-acid residue. Met-, Cys- and His-containing peptides were derivatized against Hg, Au and Pt compounds, while Tyr-, Glu-, Asp-, Asn- and Gln-containing peptides were assessed against Pb compounds. A total of 1668 reactive conditions were examined using mass spectrometry and were compiled into heavy-atom reactivity tables. The results showed that heavy-atom derivatization reactions are highly linked to buffer and pH, with the most accommodating buffer being MES at pH 6. A group of 21 compounds were identified as most successful irrespective of ligand or buffer/pH conditions. To assess the applicability of the peptide heavy-atom reactivity to proteins, lysozyme crystals were derivatized with a list of peptide-reactive compounds that included both known and new compounds for lysozyme derivatization. The results showed highly consistent heavy-atom reactivities between the peptides and lysozyme.« less

Generation of Antigen Microarrays to Screen for Autoantibodies in Heart Failure and Heart Transplantation.

PubMed

Chruscinski, Andrzej; Huang, Flora Y Y; Nguyen, Albert; Lioe, Jocelyn; Tumiati, Laura C; Kozuszko, Stella; Tinckam, Kathryn J; Rao, Vivek; Dunn, Shannon E; Persinger, Michael A; Levy, Gary A; Ross, Heather J

2016-01-01

Autoantibodies directed against endogenous proteins including contractile proteins and endothelial antigens are frequently detected in patients with heart failure and after heart transplantation. There is evidence that these autoantibodies contribute to cardiac dysfunction and correlate with clinical outcomes. Currently, autoantibodies are detected in patient sera using individual ELISA assays (one for each antigen). Thus, screening for many individual autoantibodies is laborious and consumes a large amount of patient sample. To better capture the broad-scale antibody reactivities that occur in heart failure and post-transplant, we developed a custom antigen microarray technique that can simultaneously measure IgM and IgG reactivities against 64 unique antigens using just five microliters of patient serum. We first demonstrated that our antigen microarray technique displayed enhanced sensitivity to detect autoantibodies compared to the traditional ELISA method. We then piloted this technique using two sets of samples that were obtained at our institution. In the first retrospective study, we profiled pre-transplant sera from 24 heart failure patients who subsequently received heart transplants. We identified 8 antibody reactivities that were higher in patients who developed cellular rejection (2 or more episodes of grade 2R rejection in first year after transplant as defined by revised criteria from the International Society for Heart and Lung Transplantation) compared with those who did have not have rejection episodes. In a second retrospective study with 31 patients, we identified 7 IgM reactivities that were higher in heart transplant recipients who developed antibody-mediated rejection (AMR) compared with control recipients, and in time course studies, these reactivities appeared prior to overt graft dysfunction. In conclusion, we demonstrated that the autoantibody microarray technique outperforms traditional ELISAs as it uses less patient sample, has increased sensitivity, and can detect autoantibodies in a multiplex fashion. Furthermore, our results suggest that this autoantibody array technology may help to identify patients at risk of rejection following heart transplantation and identify heart transplant recipients with AMR.

Generation of Antigen Microarrays to Screen for Autoantibodies in Heart Failure and Heart Transplantation

PubMed Central

Chruscinski, Andrzej; Huang, Flora Y. Y.; Nguyen, Albert; Lioe, Jocelyn; Tumiati, Laura C.; Kozuszko, Stella; Tinckam, Kathryn J.; Rao, Vivek; Dunn, Shannon E.; Persinger, Michael A.; Levy, Gary A.; Ross, Heather J.

2016-01-01

Autoantibodies directed against endogenous proteins including contractile proteins and endothelial antigens are frequently detected in patients with heart failure and after heart transplantation. There is evidence that these autoantibodies contribute to cardiac dysfunction and correlate with clinical outcomes. Currently, autoantibodies are detected in patient sera using individual ELISA assays (one for each antigen). Thus, screening for many individual autoantibodies is laborious and consumes a large amount of patient sample. To better capture the broad-scale antibody reactivities that occur in heart failure and post-transplant, we developed a custom antigen microarray technique that can simultaneously measure IgM and IgG reactivities against 64 unique antigens using just five microliters of patient serum. We first demonstrated that our antigen microarray technique displayed enhanced sensitivity to detect autoantibodies compared to the traditional ELISA method. We then piloted this technique using two sets of samples that were obtained at our institution. In the first retrospective study, we profiled pre-transplant sera from 24 heart failure patients who subsequently received heart transplants. We identified 8 antibody reactivities that were higher in patients who developed cellular rejection (2 or more episodes of grade 2R rejection in first year after transplant as defined by revised criteria from the International Society for Heart and Lung Transplantation) compared with those who did have not have rejection episodes. In a second retrospective study with 31 patients, we identified 7 IgM reactivities that were higher in heart transplant recipients who developed antibody-mediated rejection (AMR) compared with control recipients, and in time course studies, these reactivities appeared prior to overt graft dysfunction. In conclusion, we demonstrated that the autoantibody microarray technique outperforms traditional ELISAs as it uses less patient sample, has increased sensitivity, and can detect autoantibodies in a multiplex fashion. Furthermore, our results suggest that this autoantibody array technology may help to identify patients at risk of rejection following heart transplantation and identify heart transplant recipients with AMR. PMID:26967734

Integrating planning and reactive control

NASA Technical Reports Server (NTRS)

Rosenschein, Stanley J.; Kaelbling, Leslie Pack

1989-01-01

Artificial intelligence research on planning is concerned with designing control systems that choose actions by manipulating explicit descriptions of the world state, the goal to be achieved, and the effects of elementary operations available to the system. Because planning shifts much of the burden of reasoning to the machine, it holds great appeal as a high-level programming method. Experience shows, however, that it cannot be used indiscriminately because even moderately rich languages for describing goals, states, and the elementary operators lead to computational inefficiencies that render the approach unsuitable for realistic applications. This inadequacy has spawned a recent wave of research on reactive control or situated activity in which control systems are modeled as reacting directly to the current situation rather than as reasoning about the future effects of alternative action sequences. While this research has confronted the issue of run-time tractability head on, in many cases it has done so by sacrificing the advantages of declarative planning techniques. Ways in which the two approaches can be unified are discussed. The authors begin by modeling reactive control systems as state machines that map a stream of sensory inputs to a stream of control outputs. These machines can be decomposed into two continuously active subsystems: the planner and the execution module. The planner computes a plan, which can be seen as a set of bits that control the behavior of the execution module. An important element of this work is the formulation of a precise semantic interpretation for the inputs and outputs of the planning system. They show that the distinction between planned and reactive behavior is largely in the eye of the beholder: systems that seem to compute explicit plans can be redescribed in situation-action terms and vice versa. They also discuss practical programming techniques that allow the advantages of declarative programming and guaranteed reactive response to be achieved simultaneously.

Controlling plasma stimulated media in cancer treatment application

NASA Astrophysics Data System (ADS)

Yan, Dayun; Sherman, Jonathan H.; Cheng, Xiaoqian; Ratovitski, Edward; Canady, Jerome; Keidar, Michael

2014-12-01

Cold atmospheric plasma (CAP) constitutes a "cocktail" of various reactive species. Accumulating evidence shows the effectiveness of CAP in killing cancer cells and decreasing the tumor size, which provides a solid basis for its potential use in cancer treatment. Currently, CAP is mainly used to directly treat cancer cells and trigger the death of cancer cells via apoptosis or necrosis. By altering the concentration of fetal bovine serum in Dulbecco's modified Eagle's medium and the temperature to store CAP stimulated media, we demonstrated controllable strategies to harness the stimulated media to kill glioblastoma cells in vitro. This study demonstrated the significant role of media in killing cancer cells via the CAP treatment.

Automatic reactor control system for transient operation

NASA Astrophysics Data System (ADS)

Lipinski, Walter C.; Bhattacharyya, Samit K.; Hanan, Nelson A.

Various programmatic considerations have delayed the upgrading of the TREAT reactor and the performance of the control system is not yet experimentally verified. The current schedule calls for the upgrading activities to occur last in the calendar year 1987. Detailed simulation results, coupled with earlier validation of individual components of the control strategy in TREAT, verify the performance of the algorithms. The control system operates within the safety envelope provided by a protection system designed to ensure reactor safety under conditions of spurious reactivity additions. The approach should be directly applicable to MMW systems, with appropriate accounting of temperature rate limitations of key components and of the inertia of the secondary system components.

Chemopreventive Strategies for Inflammation-Related Carcinogenesis: Current Status and Future Direction

PubMed Central

Kanda, Yusuke; Osaki, Mitsuhiko; Okada, Futoshi

2017-01-01

A sustained and chronically-inflamed environment is characterized by the presence of heterogeneous inflammatory cellular components, including neutrophils, macrophages, lymphocytes and fibroblasts. These infiltrated cells produce growth stimulating mediators (inflammatory cytokines and growth factors), chemotactic factors (chemokines) and genotoxic substances (reactive oxygen species and nitrogen oxide) and induce DNA damage and methylation. Therefore, chronic inflammation serves as an intrinsic niche for carcinogenesis and tumor progression. In this article, we summarize the up-to-date findings regarding definitive/possible causes and mechanisms of inflammation-related carcinogenesis derived from experimental and clinical studies. We also propose 10 strategies, as well as candidate agents for the prevention of inflammation-related carcinogenesis. PMID:28422073

Quantifying Transport Between the Tropical and Mid-Latitude Lower Stratosphere

PubMed

Volk; Elkins; Fahey; Salawitch; Dutton; Gilligan; Proffitt; Loewenstein; Podolske; Minschwaner; Margitan; Chan

1996-06-21

Airborne in situ observations of molecules with a wide range of lifetimes (methane, nitrous oxide, reactive nitrogen, ozone, chlorinated halocarbons, and halon-1211), used in a tropical tracer model, show that mid-latitude air is entrained into the tropical lower stratosphere within about 13.5 months; transport is faster in the reverse direction. Because exchange with the tropics is slower than global photochemical models generally assume, ozone at mid-latitudes appears to be more sensitive to elevated levels of industrial chlorine than is currently predicted. Nevertheless, about 45 percent of air in the tropical ascent region at 21 kilometers is of mid-latitude origin, implying that emissions from supersonic aircraft could reach the middle stratosphere.

Structure–Reactivity Studies, Characterization, and Transformation of Intermediates by Lithium Chloride in the Direct Insertion of Alkyl and Aryl Iodides to Metallic Zinc Powder

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

Feng, Chao; Easter, Quinn T.; Blum, Suzanne A.

Employment of fluorophore-tagged alkyl and aryl iodides permitted detection of persistent surface intermediates during their direct insertion to commercially available zinc powder. The sensitivity of this subensemble microscopy technique enabled structure–reactivity studies in the formation of intermediates that are present in quantities sufficiently low as to have been undetected previously by traditional ensemble analytical techniques. In these surface intermediates we transformed them using lithium chloride, which lead to the assignment of the mechanistic role of lithium chloride as changing the rate-determining step in the reaction by lowering the barrier for solubilization of these otherwise persistent surface organometallic intermediates. The temperaturemore » dependence/qualitative barrier of the direct insertion step was determined independently from the solubilization step and from the barrier for the overall reaction. Detection of these zinc surface intermediates at the single-molecule level, i.e., of individual surface organometallic species, has been achieved for the first time. Energy dispersive X-ray spectroscopy (EDS) measurements of the elemental composition of the surface of the zinc powder determined that lithium chloride does not clean the surface of the oxides; instead, pretreatment of the surface with TMSCl effects partial removal of surface oxides after the 2 h pretreatment time previously reported in the empirically optimized synthetic procedure. The current limitations of this microscopy approach are also determined and discussed with respect to the addition of solid reagents during in operando imaging. Characterization of the resulting soluble fluorophore-tagged organozinc/LiCl complex by 1H NMR spectroscopy, mass spectrometry, and fluorescence spectroscopy provided insight into its solution dynamics and chemical exchange processes.« less

Structure–Reactivity Studies, Characterization, and Transformation of Intermediates by Lithium Chloride in the Direct Insertion of Alkyl and Aryl Iodides to Metallic Zinc Powder

DOE PAGES

Feng, Chao; Easter, Quinn T.; Blum, Suzanne A.

2017-02-03

Employment of fluorophore-tagged alkyl and aryl iodides permitted detection of persistent surface intermediates during their direct insertion to commercially available zinc powder. The sensitivity of this subensemble microscopy technique enabled structure–reactivity studies in the formation of intermediates that are present in quantities sufficiently low as to have been undetected previously by traditional ensemble analytical techniques. In these surface intermediates we transformed them using lithium chloride, which lead to the assignment of the mechanistic role of lithium chloride as changing the rate-determining step in the reaction by lowering the barrier for solubilization of these otherwise persistent surface organometallic intermediates. The temperaturemore » dependence/qualitative barrier of the direct insertion step was determined independently from the solubilization step and from the barrier for the overall reaction. Detection of these zinc surface intermediates at the single-molecule level, i.e., of individual surface organometallic species, has been achieved for the first time. Energy dispersive X-ray spectroscopy (EDS) measurements of the elemental composition of the surface of the zinc powder determined that lithium chloride does not clean the surface of the oxides; instead, pretreatment of the surface with TMSCl effects partial removal of surface oxides after the 2 h pretreatment time previously reported in the empirically optimized synthetic procedure. The current limitations of this microscopy approach are also determined and discussed with respect to the addition of solid reagents during in operando imaging. Characterization of the resulting soluble fluorophore-tagged organozinc/LiCl complex by 1H NMR spectroscopy, mass spectrometry, and fluorescence spectroscopy provided insight into its solution dynamics and chemical exchange processes.« less

Dietary phytochemicals and cancer prevention: Nrf2 signaling, epigenetics, and cell death mechanisms in blocking cancer initiation and progression.

PubMed

Lee, Jong Hun; Khor, Tin Oo; Shu, Limin; Su, Zheng-Yuan; Fuentes, Francisco; Kong, Ah-Ng Tony

2013-02-01

Reactive metabolites from carcinogens and oxidative stress can drive genetic mutations, genomic instability, neoplastic transformation, and ultimately carcinogenesis. Numerous dietary phytochemicals in vegetables/fruits have been shown to possess cancer chemopreventive effects in both preclinical animal models and human epidemiological studies. These phytochemicals could prevent the initiation of carcinogenesis via either direct scavenging of reactive oxygen species/reactive nitrogen species (ROS/RNS) or, more importantly, the induction of cellular defense detoxifying/antioxidant enzymes. These defense enzymes mediated by Nrf2-antioxidative stress and anti-inflammatory signaling pathways can contribute to cellular protection against ROS/RNS and reactive metabolites of carcinogens. In addition, these compounds would kill initiated/transformed cancer cells in vitro and in in vivo xenografts via diverse anti-cancer mechanisms. These mechanisms include the activation of signaling kinases (e.g., JNK), caspases and the mitochondria damage/cytochrome c pathways. Phytochemicals may also have anti-cancer effects by inhibiting the IKK/NF-κB pathway, inhibiting STAT3, and causing cell cycle arrest. In addition, other mechanisms may include epigenetic alterations (e.g., inhibition of HDACs, miRNAs, and the modification of the CpG methylation of cancer-related genes). In this review, we will discuss: the current advances in the study of Nrf2 signaling; Nrf2-deficient tumor mouse models; the epigenetic control of Nrf2 in tumorigenesis and chemoprevention; Nrf2-mediated cancer chemoprevention by naturally occurring dietary phytochemicals; and the mutation or hyper-expression of the Nrf2-Keap1 signaling pathway in advanced tumor cells. The future development of dietary phytochemicals for chemoprevention must integrate in vitro signaling mechanisms, relevant biomarkers of human diseases, and combinations of different phytochemicals and/or non-toxic therapeutic drugs, including NSAIDs. Copyright © 2012 Elsevier Inc. All rights reserved.

Immunization with Hypoallergens of Shrimp Allergen Tropomyosin Inhibits Shrimp Tropomyosin Specific IgE Reactivity

PubMed Central

Wai, Christine Y. Y.; Leung, Nicki Y. H.; Ho, Marco H. K.; Gershwin, Laurel J.; Shu, Shang An; Leung, Patrick S. C.; Chu, Ka Hou

2014-01-01

Designer proteins deprived of its IgE-binding reactivity are being sought as a regimen for allergen-specific immunotherapy. Although shrimp tropomyosin (Met e 1) has long been identified as the major shellfish allergen, no immunotherapy is currently available. In this study, we aim at identifying the Met e 1 IgE epitopes for construction of hypoallergens and to determine the IgE inhibitory capacity of the hypoallergens. IgE-binding epitopes were defined by three online computational models, ELISA and dot-blot using sera from shrimp allergy patients. Based on the epitope data, two hypoallergenic derivatives were constructed by site-directed mutagenesis (MEM49) and epitope deletion (MED171). Nine regions on Met e 1 were defined as the major IgE-binding epitopes. Both hypoallergens MEM49 and MED171 showed marked reduction in their in vitro reactivity towards IgE from shrimp allergy patients and Met e 1-sensitized mice, as well as considerable decrease in induction of mast cell degranulation as demonstrated in passive cutaneous anaphylaxis assay. Both hypoallergens were able to induce Met e 1-recognizing IgG antibodies in mice, specifically IgG2a antibodies, that strongly inhibited IgE from shrimp allergy subjects and Met e 1-sensitized mice from binding to Met e 1. These results indicate that the two designer hypoallergenic molecules MEM49 and MED171 exhibit desirable preclinical characteristics, including marked reduction in IgE reactivity and allergenicity, as well as ability to induce blocking IgG antibodies. This approach therefore offers promises for development of immunotherapeutic regimen for shrimp tropomyosin allergy. PMID:25365343

Inactivation of Candida glabrata by a humid DC argon discharge afterglow: dominant contributions of short-lived aqueous active species

NASA Astrophysics Data System (ADS)

Xiong, Qing; Liu, Hongbin; Lu, Weiping; Chen, Qiang; Xu, Le; Wang, Xia; Zhu, Qunlin; Zeng, Xue; Yi, Ping

2017-05-01

Plasma medicine applications are currently attracting significant interest all over the world. Bactericidal treatments of Candida glabrata cultured in saline suspension are performed in this study by a room-temperature reactive afterglow of a DC-driven argon discharge. Water vapor was added to the discharge to study the inactivation contributions of reactive hydrolytic species including OH and H2O2 transporting along the gas flow to the treated solutions. The inactivation results indicate that the dominant roles in the bactericidal treatments are played by the short-lived aqueous active species, but not the stable species like H2O2aq (aq indicates an aqueous species). Further analysis shows that the ·OHaq radicals play an important role in the inactivation process. The ·OHaq radicals in the suspension are mostly produced from the direct dissolution of the OH species in the reactive afterglow. With the increase of added water vapor content, the ·OHaq production increases and enhances the inactivation efficiency of C. glabrata. Furthermore, it is found that the ambient air diffusion shows essential effects on the bactericidal activity of the remote humid argon discharge. Higher bactericidal effects can be obtained in open-space treatments compared to in a controlled Ar + H2O gas atmosphere. Key active air-byproduct species are believed to be generated in the suspension during the treatments and contributing to the inactivation process. Based on chemical analysis, the peroxynitrous acid ONOOHaq is considered as the key antimicrobial air-byproduct species. These results indicate the important dependence of plasma biomedical effects on the processing environment, which finally relates to the critical contributions of the key reactive species formed therein.

Persistence of Multiple Tumor-Specific T-Cell Clones Is Associated with Complete Tumor Regression in a Melanoma Patient Receiving Adoptive Cell Transfer Therapy

PubMed Central

Zhou, Juhua; Dudley, Mark E.; Rosenberg, Steven A.; Robbins, Paul F.

2007-01-01

Summary The authors recently reported that adoptive immunotherapy with autologous tumor-reactive tumor infiltrating lymphocytes (TILs) immediately following a conditioning nonmyeloablative chemotherapy regimen resulted in an enhanced clinical response rate in patients with metastatic melanoma. These observations led to the current studies, which are focused on a detailed analysis of the T-cell antigen reactivity as well as the in vivo persistence of T cells in melanoma patient 2098, who experienced a complete regression of all metastatic lesions in lungs and soft tissues following therapy. Screening of an autologous tumor cell cDNA library using transferred TILs resulted in the identification of novel mutated growth arrest-specific gene 7 (GAS7) and glyceral-dehyde-3-phosphate dehydrogenase (GAPDH) gene transcripts. Direct sequence analysis of the expressed T-cell receptor beta chain variable regions showed that the transferred TILs contained multiple T-cell clonotypes, at least six of which persisted in peripheral blood for a month or more following transfer. The persistent T cells recognized both the mutated GAS7 and GAPDH. These persistent tumor-reactive T-cell clones were detected in tumor cell samples obtained from the patient following adoptive cell transfer and appeared to be represented at higher levels in the tumor sample obtained 1 month following transfer than in the peripheral blood obtained at the same time. Overall, these results indicate that multiple tumor-reactive T cells can persist in the peripheral blood and at the tumor site for prolonged times following adoptive transfer and thus may be responsible for the complete tumor regression in this patient. PMID:15614045

Quantifying reactivity for electrophilic aromatic substitution reactions with Hirshfeld charge.

PubMed

Liu, Shubin

2015-03-26

An electrophilic aromatic substitution is a process where one atom or group on an aromatic ring is replaced by an incoming electrophile. The reactivity and regioselectivity of this category of reactions is significantly impacted by the group that is already attached to the aromatic ring. Groups promoting substitution at the ortho/para and meta position are called ortho/para and meta directing groups, respectively. Earlier, we have shown that regioselectivity of the electrophilic aromatic substitution is dictated by the nucleophilicity of the substituted aromatic ring, which is proportional to the Hirshfeld charge on the regioselective site. Ortho/para directing groups have the largest negative charge values at the ortho/para positions, whereas meta directing groups often have the largest negative charge value at the meta position. The electron donation or acceptance feature of a substitution group is irrelevant to the regioselectivity. In this contribution, we extend our previous study by quantifying the reactivity for this kind of reactions. To that end, we examine the transition-state structure and activation energy of an identity reaction for a series of monosubstituted-benzene molecules reacting with hydrogen fluoride using BF3 as the catalyst in the gas phase. A total of 18 substitution groups will be considered, nine of which are ortho/para directing and the other nine groups meta directing. From this study, we found that the barrier height of these reactions strongly correlates with the Hirshfeld charge on the regioselective site for both ortho/para and meta directing groups, with the correlation coefficient R(2) both better than 0.96. We also discovered a less accurate correlation between the barrier height and HOMO energy. These results reconfirm the validity and effectiveness of employing the Hirshfeld charge as a reliable descriptor of both reactivity and regioselectivity for this vastly important category of chemical transformations.

In Search for Boundary Conditions of Reconsolidation: A Failure of Fear Memory Interference

PubMed Central

Schroyens, Natalie; Beckers, Tom; Kindt, Merel

2017-01-01

The presentation of a fear memory cue can result in mere memory retrieval, destabilization of the reactivated memory trace, or the formation of an extinction memory. The interaction between the degree of novelty during reactivation and previous learning conditions is thought to determine the outcome of a reactivation session. This study aimed to evaluate whether contextual novelty can prevent cue-induced destabilization and disruption of a fear memory acquired by non-asymptotic learning. To this end, fear memory was reactivated in a novel context or in the original context of learning, and fear memory reactivation was followed by the administration of propranolol, an amnestic drug. Remarkably, fear memory was not impaired by post-reactivation propranolol administration or extinction training under the usual conditions used in our lab, irrespective of the reactivation context. These unexpected findings are discussed in the light of our current experimental parameters and alleged boundary conditions on memory destabilization. PMID:28469565

Relative reactivity of amino acids with chlorine in mixtures.

PubMed

Na, Chongzheng; Olson, Terese M

2007-05-01

The relative reactivity of chlorine with amino acids is an important determinant of the resulting chlorination products in systems where chlorine is the limiting reagent, for example, in the human gastrointestinal tract after consumption of chlorine-containing water, or during food preparation with chlorinated water. Since few direct determinations of the initial reactivity of chlorine with amino acids have been made, 17 amino acids were compared in this study using competitive kinetic principles. The experimental results showed that (1) most amino acids have similar initial reactivities at neutral pH; (2) amino acids with thiol groups such as methionine and cysteine are exceptionally reactive and produce sulfoxides; (3) amino acids without thiol groups primarily undergo monochlorination of the amino nitrogen; and (4) glycine and proline are the least reactive. Dichlorination was estimated to occur with approximately 26% of the amino acid groups when the total amino acid: chlorine concentrations were equal.

Budget of the OH reactivity in the North China Plain in summer- and wintertime: Results from recent field campaigns

NASA Astrophysics Data System (ADS)

Fuchs, H.; Tan, Z.; Lu, K.; Bohn, B.; Borchardt, J.; Broch, S.; Brown, S. S.; Dong, H.; Gkatzelis, G.; Gomm, S.; Häseler, R.; He, L. Y.; Hohaus, T.; Hofzumahaus, A.; Holland, F.; Kiendler-Scharr, A.; Li, X.; Liu, Y.; Lu, S.; Min, K. E.; Novelli, A.; Rohrer, F.; Shao, M.; Wang, B.; Wang, M.; Wu, Y.; Zeng, L.; Zhang, Y.; Wegener, R.; Wahner, A.; Zhang, Y.

2016-12-01

Two comprehensive field campaigns were conducted in the densely populated North China Plain in summer 2014 and winter 2016. In 2014, the measurement site was located in a botanic garden close to the smaller town of Wangdu without major industry, but influenced by regional transportation of air pollution. In 2016, measurements were done close to Beijing and this site was partly impacted by wintertime pollution events. The loss rate coefficient of atmospheric hydroxyl radicals (OH) was quantified by direct measurements of the OH reactivity. Concurrent measurements of OH reactants allow for the determination of calculated OH reactivity. The comparison between measured and calculated OH reactivity can be used to quantify the fraction of missing OH reactivity. Closure of OH reactivity in these campaigns for different seasons will be investigated and compared with results from previous campaigns in China.

Parental Management of Peers and Autonomic Nervous System Reactivity in Predicting Adolescent Peer Relationships

ERIC Educational Resources Information Center

Tu, Kelly M.; Erath, Stephen A.; El-Sheikh, Mona

2017-01-01

The present study examined sympathetic and parasympathetic indices of autonomic nervous system reactivity as moderators of the prospective association between parental management of peers via directing of youths' friendships and peer adjustment in a sample of typically developing adolescents. Participants included 246 adolescents at Time 1 (T1)…

Patterns of Children's Adrenocortical Reactivity to Interparental Conflict and Associations with Child Adjustment: A Growth Mixture Modeling Approach

ERIC Educational Resources Information Center

Koss, Kalsea J.; George, Melissa R. W.; Davies, Patrick T.; Cicchetti, Dante; Cummings, E. Mark; Sturge-Apple, Melissa L.

2013-01-01

Examining children's physiological functioning is an important direction for understanding the links between interparental conflict and child adjustment. Utilizing growth mixture modeling, the present study examined children's cortisol reactivity patterns in response to a marital dispute. Analyses revealed three different patterns of cortisol…

Herbivore derived fatty acid-amides elicit reactive oxygen species burst in plants

USDA-ARS?s Scientific Manuscript database

The formation of a reactive oxygen species (ROS) burst is a central response of plants to many forms of stress including pathogen attack, several abiotic stresses, damage and insect infestation. These ROS act as a direct defense as well as signaling and regulatory molecules. Perception of microbe or...

Performance of a Zerovalent Iron Reactive Barrier for the Treatment of Arsenic in Groundwater: Part 2. Geochemical Modeling and Solid Phase Studies

EPA Science Inventory

Arsenic uptake processes were evaluated in a zerovalent iron reactive barrier installed at a lead smelting facility using geochemical modeling, solid-phase analysis, and X-ray absorption spectroscopy techniques. Aqueous speciation of arsenic plays a key role in directing arsenic...

Metal Cluster Models for Heterogeneous Catalysis: A Matrix-Isolation Perspective.

PubMed

Hübner, Olaf; Himmel, Hans-Jörg

2018-02-19

Metal cluster models are of high relevance for establishing new mechanistic concepts for heterogeneous catalysis. The high reactivity and particular selectivity of metal clusters is caused by the wealth of low-lying electronically excited states that are often thermally populated. Thereby the metal clusters are flexible with regard to their electronic structure and can adjust their states to be appropriate for the reaction with a particular substrate. The matrix isolation technique is ideally suited for studying excited state reactivity. The low matrix temperatures (generally 4-40 K) of the noble gas matrix host guarantee that all clusters are in their electronic ground-state (with only a very few exceptions). Electronically excited states can then be selectively populated and their reactivity probed. Unfortunately, a systematic research in this direction has not been made up to date. The purpose of this review is to provide the grounds for a directed approach to understand cluster reactivity through matrix-isolation studies combined with quantum chemical calculations. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Total OH reactivity measurements for the OH-initiated oxidation of aromatic hydrocarbons in the presence of NOx

NASA Astrophysics Data System (ADS)

Sato, Kei; Nakashima, Yoshihiro; Morino, Yu; Imamura, Takashi; Kurokawa, Jun-ichi; Kajii, Yoshizumi

2017-12-01

The total OH reactivity of the secondary products formed from the OH-initiated oxidation of toluene, p-xylene, and 1,3,5-trimethylbenzene was directly measured in the presence of NOx using a laboratory environmental chamber in order to investigate unidentified reactive species in urban air. The total OH reactivity was also calculated from the concentrations of the reactants and products, which were monitored by Fourier-transform infrared spectroscopy. The difference between the measured and calculated OH reactivity, the so-called missing OH reactivity, comprised 58-81% of the total OH reactivity of the secondary products. These results suggest that the secondary products formed from the oxidation of aromatic hydrocarbons may be important candidates in accounting for the missing OH reactivity in the analyses of urban environments. The Master Chemical Mechanism (MCM) calculations were performed to predict the temporal variation in the total OH reactivity for the oxidation of aromatic hydrocarbons. The MCM calculations successfully reproduced the observed total OH reactivity when the particle and semi-volatile product concentrations were negligibly low. The MCM calculations were used to identify the missing secondary products. The results suggest that important components of the missing OH reactivity are unsaturated multifunctional products such as unsaturated dicarbonyls, unsaturated epoxydicarbonyls, and furanones.

Software Development Technologies for Reactive, Real-Time, and Hybrid Systems: Summary of Research

NASA Technical Reports Server (NTRS)

Manna, Zohar

1998-01-01

This research is directed towards the implementation of a comprehensive deductive-algorithmic environment (toolkit) for the development and verification of high assurance reactive systems, especially concurrent, real-time, and hybrid systems. For this, we have designed and implemented the STCP (Stanford Temporal Prover) verification system. Reactive systems have an ongoing interaction with their environment, and their computations are infinite sequences of states. A large number of systems can be seen as reactive systems, including hardware, concurrent programs, network protocols, and embedded systems. Temporal logic provides a convenient language for expressing properties of reactive systems. A temporal verification methodology provides procedures for proving that a given system satisfies a given temporal property. The research covered necessary theoretical foundations as well as implementation and application issues.

Sepsis and cytomegalovirus: foes or conspirators?

PubMed

Mansfield, Sara; Grießl, Marion; Gutknecht, Michael; Cook, Charles H

2015-06-01

Cytomegalovirus (CMV) reactivation in non-immune-suppressed critically ill patients is an area of increasing interest. CMV has long been appreciated as a pathogen in immunocompromised hosts. CMV reactivates in approximately one-third of latently infected non-immune-suppressed hosts during critical illness; however, its role as a pathogen in these patients remains unclear. CMV reactivation has been linked to bacterial sepsis and likely results from inflammation, transient immune compromise, and viral epigenetic changes. While CMV may improve immune response to some bacterial infections, other data suggest that CMV induces exaggerated responses to severe infections that may be harmful to latently infected hosts. These results also suggest that previous infection history may explain significant differences seen between human septic responses and murine models of sepsis. While critically ill human hosts clearly have worse outcomes associated with CMV reactivation, determining causality remains an area of investigation, with randomized control trials currently being performed. Here we review the current literature and highlight areas for future investigation.

Heterogeneity in the development of proactive and reactive aggression in childhood: Common and specific genetic - environmental factors

PubMed Central

Lacourse, Eric; Brendgen, Mara; Vitaro, Frank; Dionne, Ginette; Tremblay, Richard Ernest; Boivin, Michel

2017-01-01

Background Few studies are grounded in a developmental framework to study proactive and reactive aggression. Furthermore, although distinctive correlates, predictors and outcomes have been highlighted, proactive and reactive aggression are substantially correlated. To our knowledge, no empirical study has examined the communality of genetic and environmental underpinning of the development of both subtypes of aggression. The current study investigated the communality and specificity of genetic-environmental factors related to heterogeneity in proactive and reactive aggression’s development throughout childhood. Methods Participants were 223 monozygotic and 332 dizygotic pairs. Teacher reports of aggression were obtained at 6, 7, 9, 10 and 12 years of age. Joint development of both phenotypes were analyzed through a multivariate latent growth curve model. Set point, differentiation, and genetic maturation/environmental modulation hypotheses were tested using a biometric decomposition of intercepts and slopes. Results Common genetic factors accounted for 64% of the total variation of proactive and reactive aggression’s intercepts. Two other sets of uncorrelated genetic factors accounted for reactive aggression’s intercept (17%) on the one hand, and for proactive (43%) and reactive (13%) aggression’s slopes on the other. Common shared environmental factors were associated with proactive aggression’s intercept (21%) and slope (26%) and uncorrelated shared environmental factors were also associated with reactive aggression’s slope (14%). Common nonshared environmental factors explained most of the remaining variability of proactive and reactive aggression slopes. Conclusions A genetic differentiation hypothesis common to both phenotypes was supported by common genetic factors associated with the developmental heterogeneity of proactive and reactive aggression in childhood. A genetic maturation hypothesis common to both phenotypes, albeit stronger for proactive aggression, was supported by common genetic factors associated with proactive and reactive aggression slopes. A shared environment set point hypothesis for proactive aggression was supported by shared environmental factors associated with proactive aggression baseline and slope. Although there are many common features to proactive and reactive aggression, the current research underscores the advantages of differentiating them when studying aggression. PMID:29211810

Nonlinear control of voltage source converters in AC-DC power system.

PubMed

Dash, P K; Nayak, N

2014-07-01

This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Vulnerability of reactive skin to electric current perception--a pilot study implicating mast cells and the lymphatic microvasculature.

PubMed

Quatresooz, Pascale; Piérard-Franchimont, Claudine; Piérard, Gérald E

2009-09-01

Sensitive/reactive skin is regarded as a manifestation of sensory irritation. This susceptibility condition to various exogenous factors suggests the intervention of some neuropeptides and other neurobiological mediators. Mast cells are among the putative implicated cells. The present immunohistochemical and morphometric study was performed on two groups of 36 gender- and age-matched subjects complaining or not from reactive skin as determined by electric current perception. In the mid upper part of the dermis, the numerical density in mast cells and the size of the microvasculature were assessed distinguishing the blood and lymphatic vessels. Globally, the distributions of data were large in reactive skin. This condition was characterized by a prominent increase in both the numerical density in mast cells and the overall size of the lymphatics. By contrast, no difference was found in the size of cutaneous blood vessels. More precisely, it appeared that a subgroup of people with reactive skin exhibited these changes contrasting with some other individuals whose data remained close to the normal range. Mast cells and lymphatics are probably involved in the process of sensory irritation affecting a subgroup of the population.

Time to wake up: reactive countermeasures to sleep inertia.

PubMed

Hilditch, Cassie J; Dorrian, Jillian; Banks, Siobhan

2016-12-07

Sleep inertia is the period of impaired performance and grogginess experienced after waking. This period of impairment is of concern to workers who are on-call, or nap during work hours, and need to perform safety-critical tasks soon after waking. While several studies have investigated the best sleep timing and length to minimise sleep inertia effects, few have focused on countermeasures -especially those that can be implemented after waking (i.e. reactive countermeasures). This structured review summarises current literature on reactive countermeasures to sleep inertia such as caffeine, light, and temperature and discusses evidence for the effectiveness and operational viability of each approach. Current literature does not provide a convincing evidence-base for a reactive countermeasure. Caffeine is perhaps the best option, although it is most effective when administered prior to sleep and is therefore not strictly reactive. Investigations into light and temperature have found promising results for improving subjective alertness; further research is needed to determine whether these countermeasures can also attenuate performance impairment. Future research in this area would benefit from study design features highlighted in this review. In the meantime, it is recommended that proactive sleep inertia countermeasures are used, and that safety-critical tasks are avoided immediately after waking.

Time to wake up: reactive countermeasures to sleep inertia

PubMed Central

HILDITCH, Cassie J.; DORRIAN, Jillian; BANKS, Siobhan

2016-01-01

Sleep inertia is the period of impaired performance and grogginess experienced after waking. This period of impairment is of concern to workers who are on-call, or nap during work hours, and need to perform safety-critical tasks soon after waking. While several studies have investigated the best sleep timing and length to minimise sleep inertia effects, few have focused on countermeasures -especially those that can be implemented after waking (i.e. reactive countermeasures). This structured review summarises current literature on reactive countermeasures to sleep inertia such as caffeine, light, and temperature and discusses evidence for the effectiveness and operational viability of each approach. Current literature does not provide a convincing evidence-base for a reactive countermeasure. Caffeine is perhaps the best option, although it is most effective when administered prior to sleep and is therefore not strictly reactive. Investigations into light and temperature have found promising results for improving subjective alertness; further research is needed to determine whether these countermeasures can also attenuate performance impairment. Future research in this area would benefit from study design features highlighted in this review. In the meantime, it is recommended that proactive sleep inertia countermeasures are used, and that safety-critical tasks are avoided immediately after waking. PMID:27193071

3D magnetohydrodynamic modelling of a dc low-current plasma arc batch reactor at very high pressure in helium

NASA Astrophysics Data System (ADS)

Lebouvier, A.; Iwarere, S. A.; Ramjugernath, D.; Fulcheri, L.

2013-04-01

This paper deals with a three-dimensional (3D) time-dependent magnetohydrodynamic (MHD) model under peculiar conditions of very high pressures (from 2 MPa up to 10 MPa) and low currents (<1 A). Studies on plasma arc working under these unusual conditions remain almost unexplored because of the technical and technological challenges to develop a reactor able to sustain a plasma at very high pressures. The combined effect of plasma reactivity and high pressure would probably open the way towards new promising applications in various fields: chemistry, lightning, materials or nanomaterial synthesis. A MHD model helps one to understand the complex and coupled phenomena surrounding the plasma which cannot be understood by simply experimentation. The model also provides data which are difficult to directly determine experimentally. The model simulates an experimental-based batch reactor working with helium. The particular reactor in question was used to investigate the Fischer-Tropsch application, fluorocarbon production and CO2 retro-conversion. However, as a first approach in terms of MHD, the model considers the case for helium as a non-reactive working gas. After a detailed presentation of the model, a reference case has been fully analysed (P = 8 MPa, I = 0.35 A) in terms of physical properties. The results show a bending of the arc and displacement of the anodic arc root towards the top of the reactor, due to the combined effects of convection, gravity and electromagnetic forces. A parametric study on the pressure (2-10 MPa) and current (0.25-0.4 A) was then investigated. The operating pressure does not show an influence on the contraction of the arc but higher pressures involve a higher natural convection in the reactor, driven by the density gradients between the cold and hot gas.

Reactive sputtering of δ-ZrH{sub 2} thin films by high power impulse magnetron sputtering and direct current magnetron sputtering

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

Högberg, Hans, E-mail: hans.hogberg@liu.se; Tengdelius, Lina; Eriksson, Fredrik

2014-07-01

Reactive sputtering by high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) of a Zr target in Ar/H{sub 2} plasmas was employed to deposit Zr-H films on Si(100) substrates, and with H content up to 61 at. % and O contents typically below 0.2 at. % as determined by elastic recoil detection analysis. X-ray photoelectron spectroscopy reveals a chemical shift of ∼0.7 eV to higher binding energies for the Zr-H films compared to pure Zr films, consistent with a charge transfer from Zr to H in a zirconium hydride. X-ray diffraction shows that the films are single-phase δ-ZrH{sub 2} (CaF{submore » 2} type structure) at H content >∼55 at. % and pole figure measurements give a 111 preferred orientation for these films. Scanning electron microscopy cross-section images show a glasslike microstructure for the HiPIMS films, while the DCMS films are columnar. Nanoindentation yield hardness values of 5.5–7 GPa for the δ-ZrH{sub 2} films that is slightly harder than the ∼5 GPa determined for Zr films and with coefficients of friction in the range of 0.12–0.18 to compare with the range of 0.4–0.6 obtained for Zr films. Wear resistance testing show that phase-pure δ-ZrH{sub 2} films deposited by HiPIMS exhibit up to 50 times lower wear rate compared to those containing a secondary Zr phase. Four-point probe measurements give resistivity values in the range of ∼100–120 μΩ cm for the δ-ZrH{sub 2} films, which is slightly higher compared to Zr films with values in the range 70–80 μΩ cm.« less

Stressful Life Events and Depression Symptoms: The Effect of Childhood Emotional Abuse on Stress Reactivity

PubMed Central

Shapero, Benjamin G.; Black, Shimrit K.; Liu, Richard T.; Klugman, Joshua; Bender, Rachel E.; Abramson, Lyn Y.; Alloy, Lauren B.

2013-01-01

Objective Stressful life events are associated with an increase in depressive symptoms and the onset of major depression. Importantly, research has shown that the role of stress changes over the course of depression. The present study extends the current literature by examining the effects of early life stress on emotional reactivity to current stressors. Method In a multiwave study (N = 281, mean age = 18.76; 68% female), we investigated the proximal changes that occur in depressive symptoms when individuals are faced with life stress and whether a history of childhood emotional abuse moderates this relationship. Results Results support the stress sensitivity hypothesis for early emotional abuse history. Individuals with greater childhood emotional abuse severity experienced greater increases in depressive symptoms when confronted with current dependent stressors, controlling for childhood physical and sexual abuse. Conclusions This study highlights the importance of emotional abuse as an indicator for reactivity to stressful life events. PMID:23800893

Adsorption And Simultaneous Dechlorination Of PCBs On GAC/Fe/Pd: Mechanistic Aspects And Reactive Capping Barrier Concept

EPA Science Inventory

There are many concerns and challenges in current remediation strategies for sediments contaminated with polychlorinated biphenyls (PCBs). Our efforts have been geared toward the development of granular activated carbon (GAC) impregnated with reactive iron/palladium (Fe/Pd) bime...

Interrelatedness of Proactive Coping, Reactive Coping, and Learned Resourcefulness

ERIC Educational Resources Information Center

Moring, John; Fuhrman, Robert; Zauszniewski, Jaclene A.

2011-01-01

Research has identified that coping strategies used by individuals depend on temporal locations of stressors. Dispositional attributes are also identified as predictors of coping. The current study identified commonalities of proactive coping, reactive coping, and learned resourcefulness measures. The analysis yielded three factors reflective of…

Coaggregation-Mediated Interactions of Streptococci and Actinomyces Detected in Initial Human Dental Plaque

PubMed Central

Palmer, Jr., Robert J.; Gordon, Sharon M.; Cisar, John O.; Kolenbrander, Paul E.

2003-01-01

Streptococci and actinomyces that initiate colonization of the tooth surface frequently coaggregate with each other as well as with other oral bacteria. These observations have led to the hypothesis that interbacterial adhesion influences spatiotemporal development of plaque. To assess the role of such interactions in oral biofilm formation in vivo, antibodies directed against bacterial surface components that mediate coaggregation interactions were used as direct immunofluorescent probes in conjunction with laser confocal microscopy to determine the distribution and spatial arrangement of bacteria within intact human plaque formed on retrievable enamel chips. In intrageneric coaggregation, streptococci such as Streptococcus gordonii DL1 recognize receptor polysaccharides (RPS) borne on other streptococci such as Streptococcus oralis 34. To define potentially interactive subsets of streptococci in the developing plaque, an antibody against RPS (anti-RPS) was used together with an antibody against S. gordonii DL1 (anti-DL1). These antibodies reacted primarily with single cells in 4-h-old plaque and with mixed-species microcolonies in 8-h-old plaque. Anti-RPS-reactive bacteria frequently formed microcolonies with anti-DL1-reactive bacteria and with other bacteria distinguished by general nucleic acid stains. In intergeneric coaggregation between streptococci and actinomyces, type 2 fimbriae of actinomyces recognize RPS on the streptococci. Cells reactive with antibody against type 2 fimbriae of Actinomyces naeslundii T14V (anti-type-2) were much less frequent than either subset of streptococci. However, bacteria reactive with anti-type-2 were seen in intimate association with anti-RPS-reactive cells. These results are the first direct demonstration of coaggregation-mediated interactions during initial plaque accumulation in vivo. Further, these results demonstrate the spatiotemporal development and prevalence of mixed-species communities in early dental plaque. PMID:12754239

Degradation of p-Nitrophenol by Lignin and Cellulose Chars: H2O2-Mediated Reaction and Direct Reaction with the Char.

PubMed

Yang, Jing; Pignatello, Joseph J; Pan, Bo; Xing, Baoshan

2017-08-15

Chars and other black carbons are reactive toward certain compounds. Such reactivity has been attributed to reduction of O 2 by persistent free radicals in the solid to H 2 O 2 , which then back-reacts with the solid to generate reactive oxygen species (ROS; especially HO • ). We studied the decomposition of p-nitrophenol (PNP) by pure lignin and cellulose chars aged in moist air or a vacuum at room temperature for up to a month. In air, the chars chemisorbed oxygen, a portion of which was liberated as H 2 O 2 when the char was submerged in water. The evolved H 2 O 2 was simultaneously decomposed by the char. PNP reacted predominantly in the sorbed state and only reduction products (phenol, catechol) were identified. Aging the char in air sharply (within hours) reduced H 2 O 2 -producing capacity and free radical concentration, but more gradually reduced PNP decay rate over the month-long period. PNP decay was only modestly suppressed (12-30%) by H 2 O 2 removal (catalase), and had little effect on the free radical signal (<6 radicals annihilated per 1000 PNP reacted). Contrasting with previous studies, the results show that direct reaction of PNP with char predominates over H 2 O 2 -dependent reactions, and the vast majority of direct-reacting sites are nonradical in character. Nonradical sites are also responsible in part for H 2 O 2 decomposition; in fact, H 2 O 2 pretreatment depleted PNP reactive sites. Lignin char was generally more reactive than cellulose char. The Fe impurity in lignin played no role. The results are relevant to the fate of pollutants in black carbon-rich environments and the use of carbons in remediation.

Removal of dissolved textile dyes from wastewater by a compost sorbent

USGS Publications Warehouse

Tsui, L.S.; Roy, W.R.; Cole, M.A.

2003-01-01

The objective of this study was to evaluate the potential for treating dye-contaminated waste streams by sorption using compost as a low-cost sorbent. A mature, thermophilic compost sample was used to sorb CI Acid Black 24, CI Acid Orange 74, CI Basic Blue 9, CI Basic Green 4, CI Direct Blue 71, CI Direct Orange 39, CI Reactive Orange 16 and CI Reactive Red 2 from solution using a batch-sorption method. With the exception of the two reactive dyes, the sorption kinetics were favourable for a continuous-flow treatment process with the compost-dye mixtures reaching a steady state within 3-5 h. Based on limited comparisons, the affinity of the compost for each dye appeared to be competitive with other non-activated carbon sorbents. The results suggest that additional research on using compost as a sorbent for dye-contaminated solutions is warranted.

Photoluminescent silicon nanocrystals with chlorosilane surfaces - synthesis and reactivity

NASA Astrophysics Data System (ADS)

Höhlein, Ignaz M. D.; Kehrle, Julian; Purkait, Tapas K.; Veinot, Jonathan G. C.; Rieger, Bernhard

2014-12-01

We present a new efficient two-step method to covalently functionalize hydride terminated silicon nanocrystals with nucleophiles. First a reactive chlorosilane layer was formed via diazonium salt initiated hydrosilylation of chlorodimethyl(vinyl)silane which was then reacted with alcohols, silanols and organolithium reagents. With organolithium compounds a side reaction is observed in which a direct functionalization of the silicon surface takes place.We present a new efficient two-step method to covalently functionalize hydride terminated silicon nanocrystals with nucleophiles. First a reactive chlorosilane layer was formed via diazonium salt initiated hydrosilylation of chlorodimethyl(vinyl)silane which was then reacted with alcohols, silanols and organolithium reagents. With organolithium compounds a side reaction is observed in which a direct functionalization of the silicon surface takes place. Electronic supplementary information (ESI) available: Detailed experimental procedures and additional NMR, PL, EDX, DLS and TEM data. See DOI: 10.1039/C4NR05888G

Mobility, Deposition and Remobilization of pre-Synthesis Stabilized Nano-scale Zero Valent Iron in Long Column Experiments

NASA Astrophysics Data System (ADS)

de Boer, C. V.; O'Carroll, D. M.; Sleep, B.

2014-12-01

Reactive zero-valent iron is currently being used for remediation of contaminated groundwater. Permeable reactive barriers are the current state-of-the-practice method for using zero-valent iron. Instead of an excavated trench filled with granular zero-valent iron, a relatively new and promising method is the injection of a nano-scale zero-valent iron colloid suspension (nZVI) into the subsurface using injection wells. One goal of nZVI injection can be to deposit zero valent iron in the aquifer and form a reactive permeable zone which is no longer bound to limited depths and plume treatment, but can also be used directly at the source. It is very important to have a good understanding of the transport behavior of nZVI during injection as well as the fate of nZVI after injection due to changes in the flow regime or water chemistry changes. So far transport was mainly tested using commercially available nZVI, however these studies suggest that further work is required as commercial nZVI was prone to aggregation, resulting in low physical stability of the suspension and very short travel distances in the subsurface. In the presented work, nZVI is stabilized during synthesis to significantly increase the physical suspension stability. To improve our understanding of nZVI transport, the feasibility for injection into various porous media materials and controlled deposition, a suite of column experiments are conducted. The column experiments are performed using a long 1.5m column and a novel nZVI measuring technique. The measuring technique was developed to non-destructively determine the concentration of nano-scale iron during the injection. It records the magnetic susceptibility, which makes it possible to get transient nZVI retention profiles along the column. These transient nZVI retention profiles of long columns provide unique insights in the transport behavior of nZVI which cannot be obtained using short columns or effluent breakthrough curves.

Involvement of mast cells and microvessels density in reactive lesions of oral cavity: A comparative immunohistochemical study.

PubMed

Ferreira, Stephany Vasco; Xavier, Flávia Caló Aquino; Freitas, Maria da Conceição Andrade de; Nunes, Fábio Daumas; Gurgel, Clarissa Araújo; Cangussu, Maria Cristina Teixeira; Martins, Manoela Domingues; Freitas, Valéria Souza; Dos Santos, Jean Nunes

2016-09-01

In view of the similarity of clinicopathological features between reactive lesions of the oral cavity, the objective of the present study was to investigate the density of MCs (mast cells) and microvessels in a series of these lesions. Thirty-seven cases of reactive lesions including fibrous hyperplasia (FH, n=10), inflammatory fibrous hyperplasia (IFH, n=10), peripheral giant cell lesion (PGCL, n=10) and lobular capillary hemangioma (LCH, n=7) were investigated using immunohistochemistry for mast cell tryptase and CD34. For comparative purposes, central giant cell lesions (CGCL, n=5) were included. A higher MC density was observed in LCH (37.01), while CGCL exhibited the lowest density (n=8.14). There was a significant difference in MC density when all reactive lesions were compared to CGCL (p=0.001). The largest mean density of microvessels was observed in LCH (n=21.69). The smallest number was observed in CGCL (n=6.24). There was a significant difference in microvessel density when the reactive lesions were compared to CGCL (p=0.003). There was a significant and direct correlation between the density of MCs and microvessels only for IFH (p=0.048) and CGCL (p=0.005). A significant and direct correlation between the mean density of MCs and microvessels was observed when the reactive lesions were analyzed as a whole (p=0.005). Our results suggest that mast cells contribute to the connective tissue framework and angiogenic function, as well as the development, of reactive lesions of the oral cavity, including FH, IFH, LCH and PGCL. Copyright © 2016 Elsevier GmbH. All rights reserved.

Low incidence of hepatitis B virus reactivation and subsequent hepatitis in patients with chronic hepatitis C receiving direct-acting antiviral therapy.

PubMed

Tamori, A; Abiru, S; Enomoto, H; Kioka, K; Korenaga, M; Tani, J; Enomoto, M; Sugiyama, M; Masaki, T; Kawada, N; Yatsuhashi, H; Nishiguchi, S; Mizokami, M

2018-05-01

To determine the clinical characteristics of hepatitis B virus (HBV) reactivation in patients undergoing interferon-free antihepatitis C virus (HCV) therapy, we examined HBV DNA in 25 HBV co-infected patients and 765 patients with resolved HBV infection during and after treatment with direct-acting antiviral agents (DAAs). Among those with HCV genotype 1, asunaprevir plus daclatasvir was administered to 160 patients, sofosbuvir (SOF) plus ledipasvir to 438 patients and paritaprevir plus ombitasvir and ritonavir to 25 patients. In total, 167 patients with genotype 2 were treated with SOF plus ribavirin. Three patients with an HBV DNA level ≥2000 IU/mL were treated with entecavir before anti-HCV therapy, without reactivation of HBV. In 3 of 22 (12%) HBV surface antigen (HBsAg)-positive patients with an HBV DNA level <2000 IU/mL, the viral load increased during treatment. However, hepatitis flare did not occur in these patients. There was no significant difference in clinical history between patients with and without HBV reactivation. Among 765 patients with resolved HBV infection, HBV reactivation occurred in 1 (0.1%) patient after initial resolution, whose HBV DNA level spontaneously decreased after DAA therapy. We compared anti-HBs titres at baseline with those at post-DAA therapy in 123 patients without HBsAg. There was no significant difference in anti-HBs levels between the two points (P = .79). In conclusion, HBV reactivation was rare in HBsAg-negative patients treated with DAA therapy. Additionally, hepatitis did not occur in HBV-reactivated patients with a baseline HBV DNA level <2000 IU/mL before DAA therapy. © 2017 John Wiley & Sons Ltd.

Effects of substrate temperature on properties of pulsed dc reactively sputtered tantalum oxide films

NASA Astrophysics Data System (ADS)

Jain, Pushkar; Juneja, Jasbir S.; Bhagwat, Vinay; Rymaszewski, Eugene J.; Lu, Toh-Ming; Cale, Timothy S.

2005-05-01

The effects of substrate heating on the stoichiometry and the electrical properties of pulsed dc reactively sputtered tantalum oxide films over a range of film thickness (0.14 to 5.4 μm) are discussed. The film stoichiometry, and hence the electrical properties, of tantalum oxide films; e.g., breakdown field, leakage current density, dielectric constant, and dielectric loss are compared for two different cases: (a) when no intentional substrate/film cooling is provided, and (b) when the substrate is water cooled during deposition. All other operating conditions are the same, and the film thickness is directly related to deposition time. The tantalum oxide films deposited on the water-cooled substrates are stoichiometric, and exhibit excellent electrical properties over the entire range of film thickness. ``Noncooled'' tantalum oxide films are stoichiometric up to ~1 μm film thickness, beyond that the deposited oxide is increasingly nonstoichiometric. The presence of partially oxidized Ta in thicker (>~1 μm) noncooled tantalum oxide films causes a lower breakdown field, higher leakage current density, higher apparent dielectric constant, and dielectric loss. The growth of nonstoichiometric tantalum oxide in thicker noncooled films is attributed to decreased surface oxygen concentration due to oxygen recombination and desorption at higher film temperatures (>~100 °C). The quantitative results presented reflect experience with a specific piece of equipment; however, the procedures presented can be used to characterize deposition processes in which film stoichiometry can change.

EthA, a Common Activator of Thiocarbamide-Containing Drugs Acting on Different Mycobacterial Targets▿

PubMed Central

Dover, Lynn G.; Alahari, Anuradha; Gratraud, Paul; Gomes, Jessica M.; Bhowruth, Veemal; Reynolds, Robert C.; Besra, Gurdyal S.; Kremer, Laurent

2007-01-01

Many of the current antimycobacterial agents require some form of cellular activation unmasking reactive groups, which in turn will bind to their specific targets. Therefore, understanding the mechanisms of activation of current antimycobacterials not only helps to decipher mechanisms of drug resistance but may also facilitate the development of alternative activation strategies or of analogues that do not require such processes. Herein, through the use of genetically defined strains of Mycobacterium bovis BCG we provide evidence that EthA, previously shown to activate ethionamide, also converts isoxyl (ISO) and thiacetazone (TAC) into reactive species. These results were further supported by the development of an in vitro assay using purified recombinant EthA, which allowed direct assessment of the metabolism of ISO. Interestingly, biochemical analysis of [14C]acetate-labeled cultures suggested that all of these EthA-activated drugs inhibit mycolic acid biosynthesis via different mechanisms through binding to specific targets. This report is also the first description of the molecular mechanism of action of TAC, a thiosemicarbazone antimicrobial agent that is still used in the treatment of tuberculosis as a second-line drug in many developing countries. Altogether, the results suggest that EthA is a common activator of thiocarbamide-containing drugs. The broad specificity of EthA can now be used to improve the activation process of these drugs, which may help overcome the toxicity problems associated with clinical thiocarbamide use. PMID:17220416

Investigating the effect of acute sleep deprivation on hypothalamic-pituitary-adrenal-axis response to a psychosocial stressor.

PubMed

Vargas, Ivan; Lopez-Duran, Nestor

2017-05-01

The hypothalamic-pituitary-adrenal (HPA) axis has been previously identified as one potential mechanism that may explain the link between sleep deprivation and negative health outcomes. However, few studies have examined the direct association between sleep deprivation and HPA-axis functioning, particularly in the context of stress. Therefore, the aim of the current study was to investigate the relationship between acute sleep deprivation and HPA-axis reactivity to a psychosocial stressor. Participants included 40 healthy, young adults between the ages of 18-29. The current protocol included spending two nights in the laboratory. After an adaptation night (night 1), participants were randomized into either a sleep deprivation condition (29 consecutive hours awake) or a control condition (night 2). Following the second night, all participants completed the Trier Social Stress Test (TSST). Salivary cortisol was collected before, during, and after the TSST. Results indicated that there were significant group differences in cortisol stress reactivity. Specifically, compared to participants in the control condition, participants in the sleep deprivation condition had greater baseline (i.e., pre-stress) cortisol, yet a blunted cortisol response to the TSST. Taken together, a combination of elevated baseline cortisol (and its subsequent effect on HPA-axis regulatory processes) and a relative 'ceiling' on the amount of cortisol a laboratory stressor can produce may explain why participants in the sleep deprivation condition demonstrated blunted cortisol responses. Copyright © 2017 Elsevier Ltd. All rights reserved.

Psychobiological responses to critically evaluated multitasking.

PubMed

Wetherell, Mark A; Craw, Olivia; Smith, Kenny; Smith, Michael A

2017-12-01

In order to understand psychobiological responses to stress it is necessary to observe how people react to controlled stressors. A range of stressors exist for this purpose; however, laboratory stressors that are representative of real life situations provide more ecologically valid opportunities for assessing stress responding. The current study assessed psychobiological responses to an ecologically valid laboratory stressor involving multitasking and critical evaluation. The stressor elicited significant increases in psychological and cardiovascular stress reactivity; however, no cortisol reactivity was observed. Other socially evaluative laboratory stressors that lead to cortisol reactivity typically require a participant to perform tasks that involve verbal responses, whilst standing in front of evaluative others. The current protocol contained critical evaluation of cognitive performance; however, this was delivered from behind a seated participant. The salience of social evaluation may therefore be related to the response format of the task and the method of evaluation. That is, the current protocol did not involve the additional vulnerability associated with in person, face-to-face contact, and verbal delivery. Critical evaluation of multitasking provides an ecologically valid technique for inducing laboratory stress and provides an alternative tool for assessing psychological and cardiovascular reactivity. Future studies could additionally use this paradigm to investigate those components of social evaluation necessary for eliciting a cortisol response.

Operating capability and current status of the reactivated NASA Lewis Research Center Hypersonic Tunnel Facility

NASA Technical Reports Server (NTRS)

Thomas, Scott R.; Trefny, Charles J.; Pack, William D.

1995-01-01

The NASA Lewis Research Center's Hypersonic Tunnel Facility (HTF) is a free-jet, blowdown propulsion test facility that can simulate up to Mach-7 flight conditions with true air composition. Mach-5, -6, and -7 nozzles, each with a 42 inch exit diameter, are available. Previously obtained calibration data indicate that the test flow uniformity of the HTF is good. The facility, without modifications, can accommodate models approximately 10 feet long. The test gas is heated using a graphite core induction heater that generates a nonvitiated flow. The combination of clean-air, large-scale, and Mach-7 capabilities is unique to the HTF and enables an accurate propulsion performance determination. The reactivation of the HTF, in progress since 1990, includes refurbishing the graphite heater, the steam generation plant, the gaseous oxygen system, and all control systems. All systems were checked out and recertified, and environmental systems were upgraded to meet current standards. The data systems were also upgraded to current standards and a communication link with NASA-wide computers was added. In May 1994, the reactivation was complete, and an integrated systems test was conducted to verify facility operability. This paper describes the reactivation, the facility status, the operating capabilities, and specific applications of the HTF.

Efficacy of novel phenoxyalkyl pyridinium oximes as brain-penetrating reactivators of cholinesterase inhibited by surrogates of sarin and VX.

PubMed

Chambers, Janice E; Chambers, Howard W; Funck, Kristen E; Meek, Edward C; Pringle, Ronald B; Ross, Matthew K

2016-11-25

Pyridinium oximes are strong nucleophiles and many are effective reactivators of organophosphate-inhibited cholinesterase (ChE). However, the current oxime reactivators are ineffective at crossing the blood-brain barrier and reactivating brain ChE in the intact organism. Our laboratories have developed a series of substituted phenoxyalkyl pyridinium oximes (US patent 9,227,937 B2) with the goal of identifying reactivators effective in crossing the blood-brain barrier. The first 35 of the series were found to have similar in vitro efficacy as reactivators of ChE inhibited by a sarin surrogate (phthalimidyl isopropyl methylphosphonate, PIMP) or a VX surrogate (nitrophenyl ethyl methylphosphonate, NEMP) in bovine brain preparations as previously observed in rat brain preparations. A number of these novel oximes have shown the ability to decrease the level of ChE inhibition in the brains of rats treated with a high sublethal dosage of either a sarin surrogate (nitrophenyl isopropyl methylphosphonate, NIMP) or the VX surrogate NEMP. Levels of reactivation at 2 h after oxime administration were up to 35% while the currently approved therapeutic, 2-PAM, yielded no reduction in brain ChE inhibition. In addition, there was evidence of attenuation of seizure-like behavior with several of the more effective novel oximes, but not 2-PAM. Therefore these novel oximes have demonstrated an ability to reactivate inhibited ChE in brain preparations from two species and in vivo data support their ability to enter the brain and provide a therapeutic action. These novel oximes have the potential to be developed into improved antidotes for nerve agent therapy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Study of the cross-reactivity of fish allergens based on a questionnaire and blood testing.

PubMed

Kobayashi, Yukihiro; Huge, Jiletu; Imamura, Shintaro; Hamada-Sato, Naoko

2016-07-01

Parvalbumin and collagen have been identified as cross-reactive allergens for fish allergies. Although doctors realize that various fish elicit allergies, the targets of food allergen labeling laws were only mackerels and salmons in Japan and mackerels in South Korea. This study aimed to reveal the causative species for fish allergy via questionnaires and blood tests. Questionnaire research was conducted in Japan via the internet concerning allergies for fish-allergic patients or their family members. Next, IgE reactivities and cross-reactivities of 26 fish species were analyzed using sera obtained from 16 Japanese patients who were allergic to fish parvalbumin or collagen by enzyme-linked immunosorbent assay (ELISA) and inhibition ELISA. Questionnaire research revealed that 88% patients cannot eat mackerel and salmon in addition to other fish. In addition, 85% respondents were not satisfied with the current food allergen labeling law. In ELISA analyses, we clarified that pooled serum obtained from patients with fish parvalbumin-specific allergies exhibited IgE reactivity to the extracts of most fish species, and pooled serum obtained from patients with fish collagen-specific allergies displayed IgE reactivity to the extracts of all types of fish. Inhibition ELISA experiments revealed cross-reactivities of parvalbumin or collagen to extracts from all fish tested. Most patients with fish allergies displayed allergic symptoms following the intake of various fish species. In addition, fish parvalbumin and collagen were causative factors of fish allergy and were highly cross-reactive fish panallergens. Therefore, current laws should be revised in Japan and South Korea. Copyright © 2016 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

Natalizumab Discontinuation and Treatment Strategies in Patients with Multiple Sclerosis (MS): A Retrospective Study from Two Italian MS Centers.

PubMed

Lo Re, Marianna; Capobianco, Marco; Ragonese, Paolo; Realmuto, Sabrina; Malucchi, Simona; Berchialla, Paola; Salemi, Giuseppe; Bertolotto, Antonio

2015-12-01

Natalizumab (NTZ) discontinuation can be followed by multiple sclerosis (MS) disease reactivation. Currently no disease-modifying drug (DMD) has been shown to be able to abolish disease reactivation. The aims of the current study were: (1) to determine the frequency of MS reactivation after NTZ discontinuation; (2) to evaluate predictors of reactivation risk, and (3) to compare the effect of different treatments in reducing this risk. Data from 132 patients with MS followed-up for 2 years before NTZ treatment and 1 year after interruption were collected from two Italian MS centers and retrospectively evaluated. Overall, 72 of 132 patients (54.5%) had relapses after NTZ discontinuation and 60 of 125 patients (48%), who had magnetic resonance imaging, had radiological reactivation. Rebound was observed in 28 of 132 patients (21.2%). A higher number of relapses in the 2 years before NTZ treatment, a longer washout period, and a lower number NTZ infusions correlated with reactivation and rebound. Untreated patients (n = 37) had higher clinical and radiological activity and rebound in comparison to patients receiving DMDs. Moreover, a lower risk of relapses was found in patients treated with second-line therapies (NTZ and fingolimod) than in those treated with first-line therapies (interferon beta, glatiramer acetate, teriflunomide, azathioprine). Interestingly, no disease reactivation in off-label treatment (rituximab, autologous hematopoietic stem cell transplantation) was observed. NTZ discontinuation is a risk for MS reactivation and rebound. An alternative treatment should be promptly resumed mainly in patients with a previous very active disease course and with a shorter NTZ therapy. Second-line therapies demonstrate superiority in preventing relapses after NTZ discontinuation.

Direct Carbon Fuel Cells: Converting Waste to Electricity

DTIC Science & Technology

2007-09-01

Contained energy DCFC single cell ....................................................................................20 10 Direct Carbon...to convert the chemical energy in solid carbon particles directly to electricity in single cell systems with (an experimentally verified...at the polarized condition. The reactivity of carbon is affected by many properties, such as crystallization , electrical conductivity, surface area

Organic chloramines in drinking water: An assessment of formation, stability, reactivity and risk.

PubMed

How, Zuo Tong; Linge, Kathryn L; Busetti, Francesco; Joll, Cynthia A

2016-04-15

Although organic chloramines are known to form during the disinfection of drinking water with chlorine, little information is currently available on their occurrence or toxicity. In a recent in vitro study, some organic chloramines (e.g. N-chloroglycine) were found to be cytotoxic and genotoxic even at micromolar concentrations. In this paper, the formation and stability of 21 different organic chloramines, from chlorination of simple amines and amino acids, were studied, and the competition between 20 amino acids during chlorination was also investigated. For comparison, chlorination of two amides was also conducted. The formation and degradation of selected organic chloramines were measured using either direct UV spectroscopic or colorimetric detection. Although cysteine, methionine and tryptophan were the most reactive amino acids towards chlorination, they did not form organic chloramines at the chlorine to precursor molar ratios that were tested. Only 6 out of the 21 organic chloramines formed had a half-life of more than 3 h, although this group included all organic chloramines formed from amines. A health risk assessment relating stability and reactivity data from this study to toxicity and precursor abundance data from the literature indicated that only N-chloroglycine is likely to be of concern due to its stability, toxicity and abundance in water. However, given the stability of organic chloramines formed from amines, more information about the toxicity and precursor abundance for these chloramines is desirable. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identification of anthropogenic impact on nitrogen cycling using stable isotopes and distibuted hydrologic modeling

NASA Astrophysics Data System (ADS)

Macko, S. A.; O'Connell, M. T.; Fu, Y.

2016-12-01

The Najinhe watershed is a topographically diverse, heavily agricultural watershed in northeastern China that provides opportunities for identification of the impact of land use on nitrogen cycling. Land use, both historic and current, influences the biological processing of nitrogen in a particular area. Soil conditions, including moisture, texture, and organic content, control the capacity of a parcel for processing reactive nitrogen. Compounds derived from natural and anthropogenic sources exhibit characteristic ratios of stable isotopes of nitrogen and oxygen that serve as tracers of origin as well as integrators of biological processes. A distributed hydrologic model coupled with one focusing on reactive transport is able to help determine locations with the highest impact on the dissolved N in this system. Gaussian Markov Random Fields were used to determine the biogeochemical influence of model locations whereas δ15N measurements from NO3- and NH4+ in soil extracts were used to calibrate and validate model predictions based on measured precipitation and streamflow values. Sources were integrated using a Bayesian mixing model to determine likely fate and transport parameters for various N inputs to the watershed. The application of the coupled hydrologic and transport models to a village scale catchment suggests integration and expansion to larger watersheds on the basin scale. Identification of sensitive parcels on multiple spatial scales can direct targeted land management efforts to mitigate ecological and health effects of reactive N in surface waters.

Comparing cerebrovascular reactivity measured using BOLD and cerebral blood flow MRI: The effect of basal vascular tension on vasodilatory and vasoconstrictive reactivity

PubMed Central

Halani, Sheliza; Kwinta, Jonathan B.; Golestani, Ali M.; Khatamian, Yasha B.; Chen, J. Jean

2016-01-01

Cerebrovascular reactivity (CVR) is an important metric of cerebrovascular health. While the BOLD fMRI method in conjunction with carbon-dioxide (CO2) based vascular manipulation has been the most commonly used, the BOLD signal is not a direct measure of vascular changes, and the use of arterial-spin labeling (ASL) cerebral blood flow (CBF) imaging is increasingly advocated. Nonetheless, given the differing dependencies of BOLD and CBF on vascular baseline conditions and the diverse CO2 manipulation types currently used in the literature, knowledge of potential biases introduced by each technique is critical for the interpretation of CVR measurements. In this work, we use simultaneous BOLD-CBF acquisitions during both vasodilatory (hypercapnic) and vasoconstrictive (hypocapnic) stimuli to measure CVR. We further imposed different levels of baseline vascular tension by inducing hypercapnic and hypocapnic baselines, separately from normocapnia by 4 mm Hg. We saw significant and diverse dependencies on vascular stimulus and baseline condition in both BOLD and CBF CVR measurements: (i) BOLD-based CVR is more sensitive to basal vascular tension than CBF-based CVR; (ii) the use of a combination of vasodilatory and vasoconstrictive stimuli maximizes the sensitivity of CBF-based CVR to vascular tension changes; (iii) the BOLD and CBF vascular response delays are both significantly lengthened at predilated baseline. As vascular tension can often be altered by potential pathology, our findings are important considerations when interpreting CVR measurements in health and disease. PMID:25655446

Spark plasma sintering of titanium aluminide intermetallics and its composites

NASA Astrophysics Data System (ADS)

Aldoshan, Abdelhakim Ahmed

Titanium aluminide intermetallics are a distinct class of engineering materials having unique properties over conventional titanium alloys. gamma-TiAl compound possesses competitive physical and mechanical properties at elevated temperature applications compared to Ni-based superalloys. gamma-TiAl composite materials exhibit high melting point, low density, high strength and excellent corrosion resistance. Spark plasma sintering (SPS) is one of the powder metallurgy techniques where powder mixture undergoes simultaneous application of uniaxial pressure and pulsed direct current. Unlike other sintering techniques such as hot iso-static pressing and hot pressing, SPS compacts the materials in shorter time (< 10 min) with a lower temperature and leads to highly dense products. Reactive synthesis of titanium aluminide intermetallics is carried out using SPS. Reactive sintering takes place between liquid aluminum and solid titanium. In this work, reactive sintering through SPS was used to fabricate fully densified gamma-TiAl and titanium aluminide composites starting from elemental powders at different sintering temperatures. It was observed that sintering temperature played significant role in the densification of titanium aluminide composites. gamma-TiAl was the predominate phase at different temperatures. The effect of increasing sintering temperature on microhardness, microstructure, yield strength and wear behavior of titanium aluminide was studied. Addition of graphene nanoplatelets to titanium aluminide matrix resulted in change in microhardness. In Ti-Al-graphene composites, a noticeable decrease in coefficient of friction was observed due to the influence of self-lubrication caused by graphene.

The Leaf Fell (the Leaf): The Online Processing of Unaccusatives

PubMed Central

Friedmann, Naama; Taranto, Gina; Shapiro, Lewis P.; Swinney, David

2012-01-01

According to the Unaccusative Hypothesis, unaccusative subjects are base-generated in object position and move to subject position. We examined this hypothesis using the cross-modal lexical priming technique, which tests whether and when an antecedent is reactivated during the online processing of a sentence. We compared sentences containing unergative verbs with sentences containing unaccusatives, both alternating and nonalternating, and found that subjects of unaccusatives reactivate after the verb, while subjects of unergatives do not. Alternating unaccusatives showed a mixed pattern of reactivation. The research directly supports the Unaccusative Hypothesis. PMID:22822348

Catalytic and reactive polypeptides and methods for their preparation and use

DOEpatents

Schultz, Peter

1994-01-01

Catalytic and reactive polypeptides include a binding site specific for a reactant or reactive intermediate involved in a chemical reaction of interest. The polypeptides further include at least one active functionality proximate the binding site, where the active functionality is capable of catalyzing or chemically participating in the chemical reaction in such a way that the reaction rate is enhanced. Methods for preparing the catalytic peptides include chemical synthesis, site-directed mutagenesis of antibody and enzyme genes, covalent attachment of the functionalities through particular amino acid side chains, and the like.

Statistical Correlation between Red Wood Ant Sites and Neotectonic Strike-Slip Faults

NASA Astrophysics Data System (ADS)

Berberich, G.; Klimetzek, D.; Wöhler, C.; Grumpe, A.

2012-04-01

Recent research in the West Eifel (West Germany) has demonstrated the correlation of soil gas anomalies and spatial distribution of red wood ant (RWA) mounds along strike-slip faults. RWA can be used as biological indicators for the identification of neotectonic fault systems (Berberich 2010, Schreiber & Berberich 2011). For myrmecologists, the causes and stringency of such a linkage are paramount, since linear patterns have been mostly associated with edge effects of forest stands and/or roads (Klimetzek 1970, Klimetzek & Kaiser 1995, Wellenstein 1990). Therefore, geostatistical techniques were applied in the West Eifel and the Bodanrück (South West Germany) to distribution data of approx. 3,000 resp. 2,300 mounds of RWA (Formica spp., Hymenoptera: Formicidae) in correlation with known neotectonic fault systems Both study areas are located in areas with a complex tectonic history. Commenced during the Neogene and persisted during the Quaternary, the uplift of both, the Rhenoherzynikum and the Black Forest, affects the dynamics of the study areas and reactivates pre-existing Palaeozoic crustal discontinuities. The West Eifel (Rhenoherzynikum) was tectonically sheared in Mesozoic and Cenozoic times. The current NW-SE-trending main stress direction opens pathways for geogenic gases. At the same time, Variscan faults as part of a conjugated shear system, are reactivated. At the Bodanrück, the compressional stress field (NNW-SSE) leads to a WSW-ENE extensional regime, in which faults cut through the entire crust (Ziegler & Dèzes 2007, Nagra 1992). The prominent large-scale neotectonic structure is the NW-SE to WNW-ESE trending "Freiburg-Bonndorf-Hegau-Bodensee-Graben" that consists of several sub-trenches (Müller et al. 2002). Field surveys indicate a possible existence of a NNE-SSW trending strike-slip fault extending east of Stein am Rhein (Büchi & Müller 2003) possibly reactivated in the Quaternary (Birkhäuser et al. 2001). Available focal mechanism solutions show a lack of possible fault planes striking between 40 and 90 degrees from north (Deichmann 1990). In addition, a NNW-SSE and NS trending fault system exist. We tested the hypothesis that the spatial distribution of RWA mounds would map the neotectonic stress field directly (Berberich et al. 2012). A statistical method for the automatic extraction of linear patterns from point clouds (Hough transform) was applied to the spatial distribution of RWA mounds. The maxima of the resulting histograms denote the preferential alignment directions. In both cases, it could be clearly shown that the spatial distribution of RWA mounds directly map the main stress field and the conjugated shear system in hierarchically succession. In the West Eifel, RWA depict mainly the opening direction of the Quaternary volcanic field (NW-SE), the WSW-ENE extensional regime and the reactivated Variscan fault systems (NNE-SSW, NE-SW). At the Bodanrück, the hypothesized existence of the NNE-SSW strike-slip fault systems (Büchi & Müller 2003) and additionally NE-SW, NNW-SSE and NS directions could be demonstrated. In conclusion, the statistical analyses show that spatial distribution of RWA maps neotectonic, gaspermeable strike-slip faults. This is especially useful in those cases, where information about the neotectonic regime is incomplete or the resolution by technical means is insufficient.

76 FR 72203 - Voltage Coordination on High Voltage Grids; Notice of Reliability Workshop Agenda

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-22

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. AD12-5-000] Voltage... currently coordinate the dispatch of reactive resources to support forecasted loads, generation and... reactive power needs of the distribution system or loads are coordinated or optimized. Panelists: Khaled...

A Reactive, Radical Approach to Engaged Scholarship

ERIC Educational Resources Information Center

Smith, Malcolm

2011-01-01

While exploring the current challenges facing academic institutions and the needs of their scholars to make their work relevant in the lives of university constituents, the author advocates for a reactive and radical approach to engaged scholarship by outlining an 8-step process that considers the importance of transformation, immediacy, and…

Increased neural and pupillary reactivity to emotional faces in adolescents with current and remitted major depressive disorder.

PubMed

Burkhouse, Katie L; Owens, Max; Feurer, Cope; Sosoo, Effua; Kudinova, Anastacia; Gibb, Brandon E

2017-05-01

This study combined multiple levels of analysis to examine whether disrupted neural and pupillary reactivity to emotional faces serves as a state- or trait-like marker of adolescent major depressive disorder (MDD). The study examined differences in pupil dilation and the event-related potential (ERP) late positive potential (LPP) component to emotional faces before and after a negative mood induction between 71 adolescents (age 11-18 years) with (i) a current diagnosis of MDD, (ii) a past episode of MDD currently in full remission and (iii) no lifetime history of any Axis I disorder. Relative to healthy control (HC) youth, adolescents with current or remitted MDD exhibited an enhanced LPP and pupillary response to all emotional facial expressions (fearful, happy and sad). This difference in reactivity between remitted depressed and HC adolescents persisted following the negative mood induction. Results also revealed that LPP and pupillary responses to emotional faces were significantly related, but only among the currently depressed adolescents. This study suggests that increased physiological and neural activation in response to social-emotional stimuli may not only characterize currently depressed adolescents, but also remains following MDD remission, potentially serving as a mechanism of risk for future depression relapse. © The Author (2017). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Direct Self-Sustained Fragmentation Cascade of Reactive Droplets

NASA Astrophysics Data System (ADS)

Inoue, Chihiro; Izato, Yu-ichiro; Miyake, Atsumi; Villermaux, Emmanuel

2017-02-01

A traditional hand-held firework generates light streaks similar to branched pine needles, with ever smaller ramifications. These streaks are the trajectories of incandescent reactive liquid droplets bursting from a melted powder. We have uncovered the detailed sequence of events, which involve a chemical reaction with the oxygen of air, thermal decomposition of metastable compounds in the melt, gas bubble nucleation and bursting, liquid ligaments and droplets formation, all occurring in a sequential fashion. We have also evidenced a rare instance in nature of a spontaneous fragmentation process involving a direct cascade from big to smaller droplets. Here, the self-sustained direct cascade is shown to proceed over up to eight generations, with well-defined time and length scales, thus answering a century old question, and enriching, with a new example, the phenomenology of comminution.

Applying PWM to control overcurrents at unbalanced faults of force-commutated VSCs used as static var compensators

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

Jiang, Y.; Ekstroem, A.

1997-01-01

This study is devoted to investigating the possibility of controlling the overcurrent of a forced-commutated voltage source converter (VSC) by PWM when the ac system is undergoing large unbalanced disturbance. The converter is supposed to be used as a static var compensator at a high power level. A novel control strategy is proposed for controlling the reactive current and the dc side voltage independently. Digital simulation results are presented and compared with the results by using just the reactive current control with fundamental switching frequency.

Early history and reactivation of the rand thrust, southern California

NASA Astrophysics Data System (ADS)

Postlethwaite, Clay E.; Jacobson, Carl E.

The Rand thrust of the Rand Mountains in the northwestern Mojave Desert separates an upper plate of quartz monzonite and quartzofeldspathic to amphibolitic gneiss from a lower plate of metagraywacke and mafic schist (Rand Schist). The Rand thrust is considered part of the regionally extensive Vincent/Chocolate Mountain thrust system, which is commonly believed to represent a Late Cretaceous subduction zone. The initial direction of dip and sense of movement along the Vincent/Chocolate Mountain thrust are controversial. Microfabrics of mylonites and quartzites from the Rand Mountains were analyzed in an attempt to determine transport direction for this region, but the results are ambiguous. In addition, the southwestern portion of the Rand thrust was found to have been reactivated as a low-angle normal fault after subduction. Reactivation might have occurred shortly after subduction, in which case it could account for the preservation of high-pressure mineral assemblages in the Rand Schist, or it could be related to mid-Tertiary extension in the western United States. In either event, the reactivation might be responsible for the complicated nature of the microfabrics. The Rand Schist exhibits an inverted metamorphic zonation. Isograds in the schist are not significantly truncated by the reactivated segment of the Rand thrust. This indicates that other segments of the Vincent/Chocolate Mountain thrust should be re-evaluated for the possibility of late movement, even if they show an apparently undisturbed inverted metamorphic zonation.

The direction of fluid flow during contact metamorphism of siliceous carbonate rocks: new data for the Monzoni and Predazzo aureoles, northern Italy, and a global review

NASA Astrophysics Data System (ADS)

Ferry, John M.; Wing, Boswell A.; Penniston-Dorland, Sarah C.; Rumble, Douglas

2002-03-01

Periclase formed in siliceous dolomitic marbles during contact metamorphism in the Monzoni and Predazzo aureoles, the Dolomites, northern Italy, by infiltration of the carbonate rocks by chemically reactive, H2O-rich fluids at 500 bar and 565-710 °C. The spatial distribution of periclase and oxygen isotope compositions is consistent with reactive fluid flow that was primarily vertical and upward in both aureoles with time-integrated flux ~5,000 and ~300 mol fluid/cm2 rock in the Monzoni and Predazzo aureoles, respectively. The new results for Monzoni and Predazzo are considered along with published studies of 13 other aureoles to draw general conclusions about the direction, amount, and controls on the geometry of reactive fluid flow during contact metamorphism of siliceous carbonate rocks. Flow in 12 aureoles was primarily vertically upward with and without a horizontal component directed away from the pluton. Fluid flow in two of the other three was primarily horizontal, directed from the pluton into the aureole. The direction of flow in the remaining aureole is uncertain. Earlier suggestions that fluid flow is often horizontal, directed toward the pluton, are likely explained by an erroneous assumption that widespread coexisting mineral reactants and products represent arrested prograde decarbonation reactions. With the exception of three samples from one aureole, time-integrated fluid flux was in the range 102-104 mol/cm2. Both the amount and direction of fluid flow are consistent with hydrodynamic models of contact metamorphism. The orientation of bedding and lithologic contacts appears to be the principal control over whether fluid flow was either primarily vertical or horizontal. Other pre-metamorphic structures, including dikes, faults, fold hinges, and fracture zones, served to channel fluid flow as well.

The direction of fluid flow during contact metamorphism of siliceous carbonate rocks: new data for the Monzoni and Predazzo aureoles, northern Italy, and a global review

NASA Astrophysics Data System (ADS)

Ferry, John; Wing, Boswell; Penniston-Dorland, Sarah; Rumble, Douglas

2001-11-01

Periclase formed in siliceous dolomitic marbles during contact metamorphism in the Monzoni and Predazzo aureoles, the Dolomites, northern Italy, by infiltration of the carbonate rocks by chemically reactive, H2O-rich fluids at 500 bar and 565-710 °C. The spatial distribution of periclase and oxygen isotope compositions is consistent with reactive fluid flow that was primarily vertical and upward in both aureoles with time-integrated flux 5,000 and 300 mol fluid/cm2 rock in the Monzoni and Predazzo aureoles, respectively. The new results for Monzoni and Predazzo are considered along with published studies of 13 other aureoles to draw general conclusions about the direction, amount, and controls on the geometry of reactive fluid flow during contact metamorphism of siliceous carbonate rocks. Flow in 12 aureoles was primarily vertically upward with and without a horizontal component directed away from the pluton. Fluid flow in two of the other three was primarily horizontal, directed from the pluton into the aureole. The direction of flow in the remaining aureole is uncertain. Earlier suggestions that fluid flow is often horizontal, directed toward the pluton, are likely explained by an erroneous assumption that widespread coexisting mineral reactants and products represent arrested prograde decarbonation reactions. With the exception of three samples from one aureole, time-integrated fluid flux was in the range 102-104 mol/cm2. Both the amount and direction of fluid flow are consistent with hydrodynamic models of contact metamorphism. The orientation of bedding and lithologic contacts appears to be the principal control over whether fluid flow was either primarily vertical or horizontal. Other pre-metamorphic structures, including dikes, faults, fold hinges, and fracture zones, served to channel fluid flow as well.

Development of a neutral embedding resin for optical imaging of fluorescently labeled biological tissue

NASA Astrophysics Data System (ADS)

Zhou, Hongfu; Gang, Yadong; Chen, Shenghua; Wang, Yu; Xiong, Yumiao; Li, Longhui; Yin, Fangfang; Liu, Yue; Liu, Xiuli; Zeng, Shaoqun

2017-10-01

Plastic embedding is widely applied in light microscopy analyses. Previous studies have shown that embedding agents and related techniques can greatly affect the quality of biological tissue embedding and fluorescent imaging. Specifically, it is difficult to preserve endogenous fluorescence using currently available acidic commercial embedding resins and related embedding techniques directly. Here, we developed a neutral embedding resin that improved the green fluorescent protein (GFP), yellow fluorescent protein (YFP), and DsRed fluorescent intensity without adjusting the pH value of monomers or reactivating fluorescence in lye. The embedding resin had a high degree of polymerization, and its fluorescence preservation ratios for GFP, YFP, and DsRed were 126.5%, 155.8%, and 218.4%, respectively.

Pharmacologic and therapeutic features of sulbutiamine.

PubMed

Van Reeth, O

1999-03-01

Asthenia is the most frequent medical reason for people seeking help from their physician. In 75% of cases, the cause is functional (either reactive or psychiatric) and in 25% it is organic. In order to provide patients with rapid relief of symptoms, appropriate antiasthenic treatment should be initiated immediately, while at the same time, adequate clinical and laboratory assessments should be performed to detect the underlying cause of asthenia. Sulbutiamine, a highly lipophilic thiamine derivative, is the only antiasthenic compound known to cross the blood-brain barrier and to be selectively active on specific brain structures directly involved in asthenia. This article reviews the current knowledge on the effects of sulbutiamine in animal models and in various forms of human asthenia. (c) 1999 Prous Science. All rights reserved.

Emotional Reactivity and Internalizing Symptoms: Moderating Role of Emotion Regulation

PubMed Central

Shapero, Benjamin G.; Abramson, Lyn Y.; Alloy, Lauren B.

2015-01-01

Emotion dysregulation has been associated with increases in many forms of psychopathology in adolescents and adults. The development of effective emotion regulation skills is important during adolescence, especially as stressful life events increase during this time. The current study examined two emotion regulation strategies, cognitive reappraisal and affective suppression, in interaction with self-report and biological measures of emotional reactivity as predictors of internalizing symptoms. A community sample of adolescents (n = 127), at an age of risk for depression and anxiety, completed self-report measures of emotional reactivity and internalizing symptoms. In addition, they completed a modified social stress task and were assessed on biological measures of reactivity and regulation. Findings suggested that the trait tendency to reappraise was associated with a reduced impact of emotional reactivity on depressive, but not anxiety symptoms. Implications for shared and specific aspects of emotional reactivity and regulation are discussed. PMID:27231404

Physiological correlates of emotional reactivity and regulation in early adolescents.

PubMed

Latham, Melissa D; Cook, Nina; Simmons, Julian G; Byrne, Michelle L; Kettle, Jonathan W L; Schwartz, Orli; Vijayakumar, Nandita; Whittle, Sarah; Allen, Nicholas B

2017-07-01

Few studies have examined physiological correlates of emotional reactivity and regulation in adolescents, despite the occurrence in this group of significant developmental changes in emotional functioning. The current study employed multiple physiological measures (i.e., startle-elicited eyeblink and ERP, skin conductance, facial EMG) to assess the emotional reactivity and regulation of 113 early adolescents in response to valenced images. Reactivity was measured while participants viewed images, and regulation was measured when they were asked to discontinue or maintain their emotional reactions to the images. Adolescent participants did not exhibit fear-potentiated startle blink. However, they did display affect-consistent zygomatic and corrugator activity during reactivity, as well as inhibition of some of these facial patterns during regulation. Skin conductance demonstrated arousal dependent activity during reactivity, and overall decreases during regulation. These findings suggest that early adolescents display reactivity to valenced pictures, but not to startle probes. Psychophysiological patterns during emotion regulation indicate additional effort and/or attention during the regulation process. Copyright © 2017 Elsevier B.V. All rights reserved.

Neuroticism and extraversion in relation to physiological stress reactivity during adolescence.

PubMed

Evans, Brittany E; Stam, Jacqueline; Huizink, Anja C; Willemen, Agnes M; Westenberg, P Michiel; Branje, Susan; Meeus, Wim; Koot, Hans M; van Lier, Pol A C

2016-05-01

The current study examined mean level and change in extraversion and neuroticism across adolescence in relation to physiological stress reactivity to social evaluation. Adolescents (n=327) from the Dutch general population reported on personality measures at five annual assessments. At age 17 years, adolescents participated in a psychosocial stress procedure characterized by social evaluation during which cortisol, heart rate, pre-ejection period (PEP) and heart rate variability were assessed. Dual latent growth curve models were fitted in which the intercepts (mean level) and slopes (change) of personality across adolescence predicted the intercepts (baseline) and slopes (reactivity) of the physiological stress measures. Most comparisons revealed no relation between personality and stress reactivity. Adolescents with higher mean level scores on extraversion did show lower cortisol reactivity. Adolescents with higher mean level neuroticism scores showed higher PEP reactivity. Our findings lend partial support for a relation between personality and physiological stress reactivity. Copyright © 2016 Elsevier B.V. All rights reserved.

Oxaliplatin antagonizes HIV-1 latency by activating NF-κB without causing global T cell activation

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

Zhu, Xiaoli; Liu, Sijie; Wang, Pengfei

Highlights: • The chemotherapeutic drug oxaliplatin reactivates latent HIV-1 in this cell line model of HIV-1 latency. • Reactivation is synergized when oxaliplatin is used in combination with valproic acid. • Oxaliplatin reactivates latent HIV-1 through activation of NF-kB and does not induce T cell activation. - Abstract: Reactivation of latent HIV-1 is a promising strategy for the clearance of the viral reservoirs. Because of the limitations of current agents, identification of new latency activators is urgently required. Using an established model of HIV-1 latency, we examined the effect of Oxaliplatin on latent HIV-1 reactivation. We showed that Oxaliplatin, alonemore » or in combination with valproic acid (VPA), was able to reactivate HIV-1 without inducing global T cell activation. We also provided evidence that Oxaliplatin reactivated HIV-1 expression by inducing nuclear factor kappa B (NF-κB) nuclear translocation. Our results indicated that Oxaliplatin could be a potential drug candidate for anti-latency therapies.« less

Grazers: biocatalysts of terrestrial silica cycling

PubMed Central

Vandevenne, Floor Ina; Barão, Ana Lúcia; Schoelynck, Jonas; Smis, Adriaan; Ryken, Nick; Van Damme, Stefan; Meire, Patrick; Struyf, Eric

2013-01-01

Silica is well known for its role as inducible defence mechanism countering herbivore attack, mainly through precipitation of opaline, biogenic silica (BSi) bodies (phytoliths) in plant epidermal tissues. Even though grazing strongly interacts with other element cycles, its impact on terrestrial silica cycling has never been thoroughly considered. Here, BSi content of ingested grass, hay and faeces of large herbivores was quantified by performing multiple chemical extraction procedures for BSi, allowing the assessment of chemical reactivity. Dissolution experiments with grass and faeces were carried out to measure direct availability of BSi for dissolution. Average BSi and readily soluble silica numbers were higher in faeces as compared with grass or hay, and differences between herbivores could be related to distinct digestive strategies. Reactivity and dissolvability of BSi increases after digestion, mainly due to degradation of organic matrices, resulting in higher silica turnover rates and mobilization potential from terrestrial to aquatic ecosystems in non-grazed versus grazed pasture systems (2 versus 20 kg Si ha−1 y−1). Our results suggest a crucial yet currently unexplored role of herbivores in determining silica export from land to ocean, where its availability is linked to eutrophication events and carbon sequestration through C–Si diatom interactions. PMID:24107532

Polarity inversion of AlN film grown on nitrided a-plane sapphire substrate with pulsed DC reactive sputtering

NASA Astrophysics Data System (ADS)

Noorprajuda, Marsetio; Ohtsuka, Makoto; Fukuyama, Hiroyuki

2018-04-01

The effect of oxygen partial pressure (PO2) on polarity and crystalline quality of AlN films grown on nitrided a-plane sapphire substrates by pulsed direct current (DC) reactive sputtering was investigated as a fundamental study. The polarity inversion of AlN from nitrogen (-c)-polarity to aluminum (+c)-polarity occurred during growth at a high PO2 of 9.4×103 Pa owing to Al-O octahedral formation at the interface of nitrided layer and AlN sputtered film which reset the polarity of AlN. The top part of the 1300 nm-thick AlN film sputtered at the high PO2 was polycrystallized. The crystalline quality was improved owing to the high kinetic energy of Al sputtered atom in the sputtering phenomena. Thinner AlN films were also fabricated at the high PO2 to eliminate the polycrystallization. For the 200 nm-thick AlN film sputtered at the high PO2, the full width at half-maximum values of the AlN (0002) and (10-12) X-ray diffraction rocking curves were 47 and 637 arcsec, respectively.

DITOP: drug-induced toxicity related protein database.

PubMed

Zhang, Jing-Xian; Huang, Wei-Juan; Zeng, Jing-Hua; Huang, Wen-Hui; Wang, Yi; Zhao, Rui; Han, Bu-Cong; Liu, Qing-Feng; Chen, Yu-Zong; Ji, Zhi-Liang

2007-07-01

Drug-induced toxicity related proteins (DITRPs) are proteins that mediate adverse drug reactions (ADRs) or toxicities through their binding to drugs or reactive metabolites. Collection of these proteins facilitates better understanding of the molecular mechanisms of drug-induced toxicity and the rational drug discovery. Drug-induced toxicity related protein database (DITOP) is such a database that is intending to provide comprehensive information of DITRPs. Currently, DITOP contains 1501 records, covering 618 distinct literature-reported DITRPs, 529 drugs/ligands and 418 distinct toxicity terms. These proteins were confirmed experimentally to interact with drugs or their reactive metabolites, thus directly or indirectly cause adverse effects or toxicities. Five major types of drug-induced toxicities or ADRs are included in DITOP, which are the idiosyncratic adverse drug reactions, the dose-dependent toxicities, the drug-drug interactions, the immune-mediated adverse drug effects (IMADEs) and the toxicities caused by genetic susceptibility. Molecular mechanisms underlying the toxicity and cross-links to related resources are also provided while available. Moreover, a series of user-friendly interfaces were designed for flexible retrieval of DITRPs-related information. The DITOP can be accessed freely at http://bioinf.xmu.edu.cn/databases/ADR/index.html. Supplementary data are available at Bioinformatics online.

Molecular Targets Underlying the Anticancer Effects of Quercetin: An Update

PubMed Central

Khan, Fazlullah; Niaz, Kamal; Maqbool, Faheem; Ismail Hassan, Fatima; Abdollahi, Mohammad; Nagulapalli Venkata, Kalyan C.; Nabavi, Seyed Mohammad; Bishayee, Anupam

2016-01-01

Quercetin, a medicinally important member of the flavonoid family, is one of the most prominent dietary antioxidants. It is present in a variety of foods—including fruits, vegetables, tea, wine, as well as other dietary supplements—and is responsible for various health benefits. Numerous pharmacological effects of quercetin include protection against diseases, such as osteoporosis, certain forms of malignant tumors, and pulmonary and cardiovascular disorders. Quercetin has the special ability of scavenging highly reactive species, such as hydrogen peroxide, superoxide anion, and hydroxyl radicals. These oxygen radicals are called reactive oxygen species, which can cause oxidative damage to cellular components, such as proteins, lipids, and deoxyribonucleic acid. Various oxygen radicals play important roles in pathophysiological and degenerative processes, such as aging. Subsequently, several studies have been performed to evaluate possible advantageous health effects of quercetin and to collect scientific evidence for these beneficial health claims. These studies also gather data in order to evaluate the exact mechanism(s) of action and toxicological effects of quercetin. The purpose of this review is to present and critically analyze molecular pathways underlying the anticancer effects of quercetin. Current limitations and future directions of research on this bioactive dietary polyphenol are also critically discussed. PMID:27589790

Mineral solubility and free energy controls on microbial reaction kinetics: Application to contaminant transport in the subsurface

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

Taillefert, Martial; Van Cappellen, Philippe

Recent developments in the theoretical treatment of geomicrobial reaction processes have resulted in the formulation of kinetic models that directly link the rates of microbial respiration and growth to the corresponding thermodynamic driving forces. The overall objective of this project was to verify and calibrate these kinetic models for the microbial reduction of uranium(VI) in geochemical conditions that mimic as much as possible field conditions. The approach combined modeling of bacterial processes using new bioenergetic rate laws, laboratory experiments to determine the bioavailability of uranium during uranium bioreduction, evaluation of microbial growth yield under energy-limited conditions using bioreactor experiments, competitionmore » experiments between metabolic processes in environmentally relevant conditions, and model applications at the field scale. The new kinetic descriptions of microbial U(VI) and Fe(III) reduction should replace those currently used in reactive transport models that couple catabolic energy generation and growth of microbial populations to the rates of biogeochemical redox processes. The above work was carried out in collaboration between the groups of Taillefert (batch reactor experiments and reaction modeling) at Georgia Tech and Van Cappellen (retentostat experiments and reactive transport modeling) at University of Waterloo (Canada).« less

Low family income and behavior problems in Norwegian preschoolers: Is child emotionality a marker for sensitivity of influence?

PubMed Central

Bøe, Tormod; Hysing, Mari; Zachrisson, Henrik Daae

2016-01-01

Background Poor children have higher rates of mental health problems compared to more affluent peers, also in progressive welfare states like Norway. Temperamental characteristics may render some children more sensitive to the adverse influence of poor economy. Objective The current study examined the direct associations between family income-to-needs and mental health, and assessed moderation by early temperamental characteristics (i.e., emotionality). Method Using data from the Norwegian Mother and Child Cohort Study, associations between income-to-needs across children's first three years, and internalizing and externalizing problems when children were five years old were examined. Differential sensitivity to family income-to-needs was assessed by investigating how emotionality, when children were one-and-a-half and three years old, moderated these associations. Results Significant main effects of income-to-needs and emotionality, and a significant interaction effect between income-to-needs and emotionality was found for externalizing problems, but not for internalizing problems. Conclusion Children in poor families with an emotionally reactive temperament had higher scores on externalizing problems when they were five compared to their less emotionally reactive peers. PMID:27035694

Effects of amphetamine on reactivity to emotional stimuli

PubMed Central

Wardle, Margaret C.; de Wit, Harriet

2011-01-01

Rationale Most studies of the reinforcing effects of stimulants have focused on the drugs’ capacity to induce positive mood (i.e., euphoria). However, recent findings suggest drugs may also alter emotional reactivity to external stimuli, and that this may occur independently of direct effects on mood. Objectives We aimed to examine effects of d-amphetamine, a prototypic stimulant, on self-reported and psychophysiological reactivity to emotional stimuli as well as overall subjective mood. We predicted that amphetamine would enhance reactivity to pleasant stimuli, particularly, stimuli with social content and that these effects would be independent of the drug’s direct effects on mood. Methods Over three sessions, 36 healthy normal adults received placebo, d-amphetamine 10 and 20 mg under counterbalanced double-blind conditions. At each session, emotional reactivity to standardized positive, neutral, and negative pictures with and without social content was measured in self-reports and facial muscles sensitive to emotional state. Drug effects on cardiovascular variables and subjective mood were also measured. Results Amphetamine produced euphoria, feelings of drug effect, and increased blood pressure. Most notably, amphetamine enhanced self-reported positive reactions to all pictures and psychophysiological reactions to positive pictures. These effects were not significantly related to drug-induced mood changes. Contrary to our hypothesis, effects of amphetamine on emotional reactivity were not moderated by social content. Conclusions This study demonstrates a previously unexamined and potentially reinforcing effect of stimulant drugs in humans, distinct from more typically measured euphorigenic effects, and suggests new areas of research in stimulant abuse risk and adaptations occurring during drug dependence. PMID:21947316

Executive functioning and substance use in adolescence: Neurobiological and behavioral perspectives.

PubMed

Kim-Spoon, Jungmeen; Kahn, Rachel E; Lauharatanahirun, Nina; Deater-Deckard, Kirby; Bickel, Warren K; Chiu, Pearl H; King-Casas, Brooks

2017-06-01

The current review is guided by the theoretical perspective that emphasizes the regulating role of executive functioning (Carver et al., 2009) and presents studies that elucidate the ways that executive functioning (inhibition and working memory) explain individual differences in adolescent substance use independently or by regulating the reactive system (reward and punishment sensitivity). Behavioral studies indicate that main effects of executive functioning on adolescent substance use are often nonsignificant or weak in effect sizes. In contrast, emerging evidence suggests consistent and stronger regulating effects of executive functioning over reward and punishment sensitivity. Functional neuroimaging studies reveal significant associations between executive functioning task-related hemodynamic responses and substance use with strong effect sizes. There is also direct evidence from studies testing statistical interactions of the regulating effects of EF-related brain activation, and indirect evidence in studies examining functional connectivity, temporal discounting, and reinforced control. We note key future directions and ways to address limitations in existing work. Copyright © 2017 Elsevier Ltd. All rights reserved.

Go in for the kill: How plants deploy effector-triggered immunity to combat pathogens. [Corrected].

PubMed

Wu, Liang; Chen, Huan; Curtis, Chad; Fu, Zheng Qing

2014-01-01

Plant resistance (R) proteins perceive specific pathogen effectors from diverse plant pathogens to initiate defense responses, designated effector-triggered immunity (ETI). Plant R proteins are mostly nucleotide binding-leucine rich repeat (NB-LRR) proteins, which recognize pathogen effectors directly or indirectly through sophisticated mechanisms. Upon activation by effector proteins, R proteins elicit robust defense responses, including a rapid burst of reactive oxygen species (ROS), induced biosynthesis and accumulation of salicylic acid (SA), a rapid programmed cell death (PCD) called hypersensitive response (HR) at the infection sites, and increased expression of pathogenesis-related (PR) genes. Initiation of ETI is correlated with a complex network of defense signaling pathways, resulting in defensive cellular responses and large-scale transcriptional reprogramming events. In this review, we highlight important recent advances on the recognition of effectors, regulation and activation of plant R proteins, dynamic intracellular trafficking of R proteins, induction of cell death, and transcriptional reprogramming associated with ETI. Current knowledge gaps and future research directions are also discussed in this review.

Go in for the kill

PubMed Central

Wu, Liang; Chen, Huan; Curtis, Chad; Fu, Zheng Qing

2014-01-01

Plant resistance (R) proteins perceive specific pathogen effectors from diverse plant pathogens to initiate defense responses, designated effector-triggered immunity (ETI). Plant R proteins are mostly nucleotide binding-leucine rich repeat (NB-LRR) proteins, which recognize pathogen effectors directly or indirectly through sophisticated mechanisms. Upon activation by effector proteins, R proteins elicit robust defense responses, including a rapid burst of reactive oxygen species (ROS), induced biosynthesis and accumulation of salicylic acid (SA), a rapid programmed cell death (PCD) called hypersensitive response (HR) at the infection sites, and increased expression of pathogenesis-related (PR) genes. Initiation of ETI is correlated with a complex network of defense signaling pathways, resulting in defensive cellular responses and large-scale transcriptional reprogramming events. In this review, we highlight important recent advances on the recognition of effectors, regulation and activation of plant R proteins, dynamic intracellular trafficking of R proteins, induction of cell death, and transcriptional reprogramming associated with ETI. Current knowledge gaps and future research directions are also discussed in this review. PMID:25513772

Analysis and experimental evaluation of shunt active power filter for power quality improvement based on predictive direct power control.

PubMed

Aissa, Oualid; Moulahoum, Samir; Colak, Ilhami; Babes, Badreddine; Kabache, Nadir

2017-10-12

This paper discusses the use of the concept of classical and predictive direct power control for shunt active power filter function. These strategies are used to improve the active power filter performance by compensation of the reactive power and the elimination of the harmonic currents drawn by non-linear loads. A theoretical analysis followed by a simulation using MATLAB/Simulink software for the studied techniques has been established. Moreover, two test benches have been carried out using the dSPACE card 1104 for the classic and predictive DPC control to evaluate the studied methods in real time. Obtained results are presented and compared in this paper to confirm the superiority of the predictive technique. To overcome the pollution problems caused by the consumption of fossil fuels, renewable energies are the alternatives recommended to ensure green energy. In the same context, the tested predictive filter can easily be supplied by a renewable energy source that will give its impact to enhance the power quality.

Probing the Reactivity of Cyclic "N,O"-Acetals versus Cyclic "O,O"-Acetals with NaBH[subscript 4] and CH[subscript 3]MgI

ERIC Educational Resources Information Center

Ciaccio, James A.; Saba, Shahrokh; Bruno, Samantha M.; Bruppacher, John H.; McKnight, Alexa G.

2018-01-01

An operationally straightforward, project-like laboratory experiment has been developed in which students directly compare the reactivity of two heterocycles, a cyclic "O,O"-acetal (standard C-O protecting group) and a cyclic "N,O"-acetal (oxazolidine), toward sodium borohydride and methylmagnesium iodide. Students synthesize a…

Temperature derivatives for fusion reactivity of D-D and D-T

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

Langenbrunner, James R.; Makaruk, Hanna Ewa

Deuterium-tritium (D-T) and deuterium-deuterium (D-D) fusion reaction rates are observable using leakage gamma flux. A direct measurement of γ-rays with equipment that exhibits fast temporal response could be used to infer temperature, if the detector signal is amenable for taking the logarithmic time-derivative, alpha. We consider the temperature dependence for fusion cross section reactivity.

High rate DC-reactive sputter deposition of Y 2O 3 film on the textured metal substrate for the superconducting coated conductor

NASA Astrophysics Data System (ADS)

Kim, Ho-Sup; Park, Chan; Ko, Rock-Kil; Shi, Dongqui; Chung, Jun-Ki; Ha, Hong-Soo; Park, Yu-Mi; Song, Kyu-Jeong; Youm, Do-Jun

2005-10-01

Y2O3 film was directly deposited on Ni-3at%W substrate by DC reactive sputtering. DC reactive sputtering was carried out using metallic Y target and water vapor for oxidizing the elements of metallic target on the substrate. The detailed conditions of DC reactive sputtering for depositions of Y2O3 films were investigated. The window of water vapor for proper growth of Y2O3 films was determined by sufficient oxidations of the Y2O3 films and the non-oxidation of the target surface, which was required for high rate sputtering. The window turned out to be fairly wide in the chamber used. As the sputtering power was raised, the deposition rate increased without narrowing the window. The fabricated Y2O3 films showed good texture qualities and surface morphologies. The YBCO film deposited directly on the Y2O3 buffered Ni-3at%W substrate showed Tc, Ic (77 K, self field), and Jc (77 K, self field) of 89 K, 64 A/cm and 1.1 MA/cm2, respectively.

Functional analysis of dengue virus (DENV) type 2 envelope protein domain 3 type-specific and DENV complex-reactive critical epitope residues.

PubMed

Pitcher, Trevor J; Sarathy, Vanessa V; Matsui, Kiyohiko; Gromowski, Gregory D; Huang, Claire Y-H; Barrett, Alan D T

2015-02-01

The dengue virus (DENV) envelope protein domain 3 (ED3) is the target of potent virus neutralizing antibodies. The DENV-2 ED3 contains adjacent type-specific and DENV complex-reactive antigenic sites that are composed of a small number of residues that were previously demonstrated to be critical for antibody binding. Site-directed mutagenesis of a DENV-2 16681 infectious clone was used to mutate critical residues in the DENV-2 type-specific (K305A and P384A) and DENV complex-reactive (K310A) antigenic sites. The K305A mutant virus multiplied like the parent virus in mosquito and mammalian cells, as did the P384A mutant virus, which required a compensatory mutation (G330D) for viability. However, the K310A mutant virus could not be recovered. The DENV-2 type-specific critical residue mutations K305A and P384A+G330D reduced the ability of DENV-2 type-specific, but not DENV complex-reactive, mAbs to neutralize virus infectivity and this was directly correlated with mAb binding affinity to the rED3 mutants. © 2015 The Authors.

Neural Correlates of Aggressive Behavior in Real Time: a Review of fMRI Studies of Laboratory Reactive Aggression

PubMed Central

Keedy, Sarah; Berman, Mitchell E.; Lee, Royce; Coccaro, Emil F.

2017-01-01

Purpose of review Aggressive behavior has adaptive value in many natural environments; however, it places substantial burden and costs on human society. For this reason, there has long been interest in understanding the neurobiological basis of aggression. This interest, and the flourishing of neuroimaging research in general, has spurred the development of a large and growing scientific literature on the topic. As a result, a neural circuit model of aggressive behavior has emerged that implicates interconnected brain regions that are involved in emotional reactivity, emotion regulation, and cognitive control. Recent findings Recently, behavioral paradigms that simulate provocative interactions have been adapted to neuroimaging protocols, providing an opportunity to directly probe the involvement of neural circuits in an aggressive interaction. Here we review neuroimaging studies of simulated aggressive interactions in research volunteers. We focus on studies that use a well-validated laboratory paradigm for reactive physical aggression and examine the neural correlates of provocation, retaliation, and evaluating punishment of an opponent. Summary Overall, the studies reviewed support the involvement of neural circuits that support emotional reactivity, emotion regulation, and cognitive control in aggressive behavior. Based on a synthesis of this literature, future research directions are discussed. PMID:29607288

Reactivity Study of Unsymmetrical β-Diketiminato Copper(I) Complexes: Effect of the Chelating Ring.

PubMed

Chuang, Wan-Jung; Hsu, Sung-Po; Chand, Kuldeep; Yu, Fu-Lun; Tsai, Cheng-Long; Tseng, Yu-Hsuan; Lu, Yuh-Hsiu; Kuo, Jen-Yu; Carey, James R; Chen, Hsuan-Ying; Chen, Hsing-Yin; Chiang, Michael Y; Hsu, Sodio C N

2017-03-06

β-Diketiminato copper(I) complexes play important roles in bioinspired catalytic chemistry and in applications to the materials industry. However, it has been observed that these complexes are very susceptible to disproportionation. Coordinating solvents or Lewis bases are typically used to prevent disproportionation and to block the coordination sites of the copper(I) center from further decomposition. Here, we incorporate this coordination protection directly into the molecule in order to increase the stability and reactivity of these complexes and to discover new copper(I) binding motifs. Here we describe the synthesis, structural characterization, and reactivity of a series of unsymmetrical N-aryl-N'-alkylpyridyl β-diketiminato copper(I) complexes and discuss the structures and reactivity of these complexes with respect to the length of the pyridyl arm. All of the aforementioned unsymmetrical ß-diketiminato copper(I) complexes bind CO reversibly and are stable to disproportionation. The binding ability of CO and the rate of pyridyl ligand decoordination of these copper(I) complexes are directly related to the competition between the degree of puckering of the chelate system and the steric demands of the N-aryl substituent.

Reactivation of oxidized PTP1B and PTEN by Thioredoxin 1

PubMed Central

Schwertassek, Ulla; Haque, Aftabul; Krishnan, Navasona; Greiner, Romy; Weingarten, Lars; Dick, Tobias P.; Tonks, Nicholas K.

2014-01-01

The transient inactivation of protein phosphatases contributes to the efficiency and temporal control of kinase-dependent signal transduction. In particular, members of the protein tyrosine phosphatase family are known to undergo reversible oxidation of their active site cysteine. The thiol oxidation step requires activation of co-localized NADPH oxidases and is mediated by locally produced ROS, in particular H2O2. How oxidized phosphatases are returned to the reduced active state is less well studied. Both major thiol reductive systems, the thioredoxin and the glutathione systems, have been implicated in the reactivation of phosphatases. Here, we show that the protein tyrosine phosphatase PTP1B and the dual-specificity phosphatase PTEN are preferentially reactivated by the thioredoxin system. We show that inducible depletion of TRX1 slows down PTEN re-activation in intact living cells. Finally, using a mechanism-based trapping approach we demonstrate direct thiol disulfide exchange between the active sites of thioredoxin and either phosphatase. The application of thioredoxin trapping mutants represents a complementary approach to direct assays of PTP oxidation in elucidating the significance of redox regulation of PTP function in the control of cell signaling. PMID:24976139

Assessing protein oxidation by inorganic nanoparticles with enzyme-linked immunosorbent assay (ELISA).

PubMed

Sun, Wenjie; Luna-Velasco, Antonia; Sierra-Alvarez, Reyes; Field, Jim A

2013-03-01

Growth in the nanotechnology industry is leading to increased production of engineered nanoparticles (NPs). This has given rise to concerns about the potential adverse and toxic effects to biological system and the environment. An important mechanism of NP toxicity is oxidative stress caused by the formation of reactive oxygen species (ROS) or via direct oxidation of biomolecules. In this study, a protein oxidation assay was developed as an indicator of biomolecule oxidation by NPs. The oxidation of the protein, bovine serum albumin (BSA) was evaluated with an enzyme-linked immunosorbent assay (ELISA) to measure the protein carbonyl derivatives formed from protein oxidation. The results showed that some NPs such as Cu(0), CuO, Mn(2)O(3), and Fe(0) caused oxidation of BSA; whereas, many of the other NPs tested were not reactive or very slowly reactive with BSA. The mechanisms involved in the oxidation of BSA protein by the reactive NPs could be attributed to the combined effects of ROS-dependent and direct protein oxidation mechanisms. The ELISA assay is a promising method for the assessment of protein oxidation by NPs, which can provide insights on NP toxicity mechanisms. Copyright © 2012 Wiley Periodicals, Inc.

In vitro ability of currently available oximes to reactivate organophosphate pesticide-inhibited human acetylcholinesterase and butyrylcholinesterase.

PubMed

Jun, Daniel; Musilova, Lucie; Musilek, Kamil; Kuca, Kamil

2011-01-01

We have in vitro tested the ability of common, commercially available, cholinesterase reactivators (pralidoxime, obidoxime, methoxime, trimedoxime and HI-6) to reactivate human acetylcholinesterase (AChE), inhibited by five structurally different organophosphate pesticides and inhibitors (paraoxon, dichlorvos, DFP, leptophos-oxon and methamidophos). We also tested reactivation of human butyrylcholinesterase (BChE) with the aim of finding a potent oxime, suitable to serve as a "pseudocatalytic" bioscavenger in combination with this enzyme. Such a combination could allow an increase of prophylactic and therapeutic efficacy of the administered enzyme. According to our results, the best broad-spectrum AChE reactivators were trimedoxime and obidoxime in the case of paraoxon, leptophos-oxon, and methamidophos-inhibited AChE. Methamidophos and leptophos-oxon were quite easily reactivatable by all tested reactivators. In the case of methamidophos-inhibited AChE, the lower oxime concentration (10(-5) M) had higher reactivation ability than the 10(-4) M concentration. Therefore, we evaluated the reactivation ability of obidoxime in a concentration range of 10(-3)-10(-7) M. The reactivation of methamidophos-inhibited AChE with different obidoxime concentrations resulted in a bell shaped curve with maximum reactivation at 10(-5) M. In the case of BChE, no reactivator exceeded 15% reactivation ability and therefore none of the oximes can be recommended as a candidate for "pseudocatalytic" bioscavengers with BChE.

Antipsychotics, chlorpromazine and haloperidol inhibit voltage-gated proton currents in BV2 microglial cells.

PubMed

Shin, Hyewon; Song, Jin-Ho

2014-09-05

Microglial dysfunction and neuroinflammation are thought to contribute to the pathogenesis of schizophrenia. Some antipsychotic drugs have anti-inflammatory activity and can reduce the secretion of pro-inflammatory cytokines and reactive oxygen species from activated microglial cells. Voltage-gated proton channels on the microglial cells participate in the generation of reactive oxygen species and neuronal toxicity by supporting NADPH oxidase activity. In the present study, we examined the effects of two typical antipsychotics, chlorpromazine and haloperidol, on proton currents in microglial BV2 cells using the whole-cell patch clamp method. Chlorpromazine and haloperidol potently inhibited proton currents with IC50 values of 2.2 μM and 8.4 μM, respectively. Chlorpromazine and haloperidol are weak bases that can increase the intracellular pH, whereby they reduce the proton gradient and affect channel gating. Although the drugs caused a marginal positive shift of the activation voltage, they did not change the reversal potential. This suggested that proton current inhibition was not due to an alteration of the intracellular pH. Chlorpromazine and haloperidol are strong blockers of dopamine receptors. While dopamine itself did not affect proton currents, it also did not alter proton current inhibition by the two antipsychotics, indicating dopamine receptors are not likely to mediate the proton current inhibition. Given that proton channels are important for the production of reactive oxygen species and possibly pro-inflammatory cytokines, the anti-inflammatory and antipsychotic activities of chlorpromazine and haloperidol may be partly derived from their ability to inhibit microglial proton currents. Copyright © 2014 Elsevier B.V. All rights reserved.

The Relative Salience of Daily and Enduring Influences on Off-Job Reactions to Work Stress.

PubMed

Calderwood, Charles; Ackerman, Phillip L

2016-12-01

Work stress is an important determinant of employee health and wellness. The occupational health community is recognizing that one contributor to these relationships may be the presence of negative off-job reactivity to work, which we argue involves continued thoughts directed towards work (cognitive reactivity), continued negative mood stemming from work (affective reactivity), and the alteration of post-work behaviours in response to work factors (behavioural reactivity). We explored the relative contributions of daily work stressors, affective traits, and subjective job stress perceptions to negative off-job reactivity. These relationships were evaluated in a study of hospital nurses (n = 75), who completed trait measures and then provided self-assessments of daily work stress and off-job reactions for four work days. The results of several multilevel analyses indicated that a main-effects model best described the data when predicting cognitive, affective, and behavioural reactivity from daily work stressors, affective traits, and subjective job stress perceptions. A series of multilevel dominance analyses revealed that subjective job stress perceptions dominated the prediction of behavioural reactivity, while trait negative affect dominated the prediction of affective reactivity. Theoretical implications and the relative salience of daily and enduring contributors to negative off-job reactivity are discussed. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Cue reactivity towards shopping cues in female participants.

PubMed

Starcke, Katrin; Schlereth, Berenike; Domass, Debora; Schöler, Tobias; Brand, Matthias

2013-03-01

Background and aims It is currently under debate whether pathological buying can be considered as a behavioural addiction. Addictions have often been investigated with cue-reactivity paradigms to assess subjective, physiological and neural craving reactions. The current study aims at testing whether cue reactivity towards shopping cues is related to pathological buying tendencies. Methods A sample of 66 non-clinical female participants rated shopping related pictures concerning valence, arousal, and subjective craving. In a subgroup of 26 participants, electrodermal reactions towards those pictures were additionally assessed. Furthermore, all participants were screened concerning pathological buying tendencies and baseline craving for shopping. Results Results indicate a relationship between the subjective ratings of the shopping cues and pathological buying tendencies, even if baseline craving for shopping was controlled for. Electrodermal reactions were partly related to the subjective ratings of the cues. Conclusions Cue reactivity may be a potential correlate of pathological buying tendencies. Thus, pathological buying may be accompanied by craving reactions towards shopping cues. Results support the assumption that pathological buying can be considered as a behavioural addiction. From a methodological point of view, results support the view that the cue-reactivity paradigm is suited for the investigation of craving reactions in pathological buying and future studies should implement this paradigm in clinical samples.

Cannabis, tobacco, and caffeine use modify the blood pressure reactivity protection of ascorbic acid.

PubMed

Brody, Stuart; Preut, Ragnar

2002-07-01

Cannabis, caffeine, and tobacco use are associated with increased mesolimbic dopamine activity. Ascorbic acid (AA) modulates some dopaminergic agent effects, and was recently found to decrease systolic blood pressure (SBP) stress reactivity. To examine how AA SBP stress reactivity protection varies by use of these substances, data from an AA trial (Cetebe, 3000 mg/day for 14 days; N=108) were compared by substance use level regarding SBP reactivity to the anticipation and actual experience phases of a standardized psychological stressor (10 min of public speaking and arithmetic). Self-reported never users of cannabis, persons not currently smoking tobacco, and persons consuming three or more caffeine beverages daily all exhibited AA SBP stress reactivity protection to the actual stressor, but not during the anticipation phase. Conversely, self-reported ever cannabis users, current tobacco smokers, and persons consuming less than three caffeine beverages daily exhibited the AA SBP protection during the anticipation phase, but only the lower caffeine consumption group exhibited AA protection during both phases. Covariates (neuroticism, extraversion, and depression scores, age, sex, body mass index) were all nonsignificant. Results are discussed in terms of dopaminergic effects of these substances, modulation of catecholaminergic and endothelial activity, and AA support of coping styles.

Stack configurations for tubular solid oxide fuel cells

DOEpatents

Armstrong, Timothy R.; Trammell, Michael P.; Marasco, Joseph A.

2010-08-31

A fuel cell unit includes an array of solid oxide fuel cell tubes having porous metallic exterior surfaces, interior fuel cell layers, and interior surfaces, each of the tubes having at least one open end; and, at least one header in operable communication with the array of solid oxide fuel cell tubes for directing a first reactive gas into contact with the porous metallic exterior surfaces and for directing a second reactive gas into contact with the interior surfaces, the header further including at least one busbar disposed in electrical contact with at least one surface selected from the group consisting of the porous metallic exterior surfaces and the interior surfaces.

Characterization of argon direct-current glow discharge with a longitudinal electric field applied at ambient air

NASA Astrophysics Data System (ADS)

Jiang, Weiman; Tang, Jie; Wang, Yishan; Zhao, Wei; Duan, Yixiang

2014-09-01

A direct-current-driven plasma jet is developed by applying a longitudinal electric field on the flowing argon at ambient air. This plasma shows a torch shape with its cross-section increased from the anode to the cathode. Comparison with its counterparts indicates that the gas flow plays a key role in variation of the plasma structure and contributes much to enlarging the plasma volume. It is also found that the circular hollow metal base promotes generation of plasma with a high-power volume density in a limited space. The optical emission spectroscopy (OES) diagnosis indicates that the plasma comprises many reactive species, such as OH, O, excited N2, and Ar metastables. Examination of the rotational and vibrational temperature indicates that the plasma is under nonequilibrium condition and the excited species OH(A 2Σ+), O(5P), and N2(C 3Πu) are partly generated by energy transfer from argon metastables. The spatially resolved OES of plasma reveals that the negative glow, Faraday dark space, and positive column are distributed across the gas gap. The absence of the anode glow is attributed to the fact that many electrons in the vicinity of the anode follow ions into the positive column due to the ambipolar diffusion in the flowing gas.

Comparative study of reference currents and DC bus voltage control for Three-Phase Four-Wire Four-Leg SAPF to compensate harmonics and reactive power with 3D SVM.

PubMed

Chebabhi, A; Fellah, M K; Kessal, A; Benkhoris, M F

2015-07-01

In this paper the performances of three reference currents and DC bus voltage control techniques for Three-Phase Four-Wire Four-Leg SAPF are compared for balanced and unbalanced load conditions. The main goals are to minimize the harmonics, reduce the magnitude of neutral current, eliminate the zero-sequence current components caused by single-phase nonlinear loads and compensate the reactive power, and on the other hand improve performances such as robustness, stabilization, trajectory pursuit, and reduce time response. The three techniques are analyzed mathematically and simulation results are compared. The techniques considered for comparative study are the PI Control, Sliding Mode Control and the Backstepping Control. Synchronous reference frame theory (SRF) in the dqo-axes is used to generate the reference currents, of the inverter. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Reactive Aggression and Posttraumatic Stress in Adolescents Affected by Hurricane Katrina

ERIC Educational Resources Information Center

Marsee, Monica A.

2008-01-01

The current study tests a theoretical model illustrating a potential pathway to reactive aggression through exposure to a traumatic event (Hurricane Katrina) in 166 adolescents (61% female, 63% Caucasian) recruited from high schools on the Gulf Coast of Mississippi. Results support an association between exposure to Hurricane Katrina and reactive…

Intentional and Reactive Inhibition during Spoken-Word Stroop Task Performance in People with Aphasia

ERIC Educational Resources Information Center

Pompon, Rebecca Hunting; McNeil, Malcolm R.; Spencer, Kristie A.; Kendall, Diane L.

2015-01-01

Purpose: The integrity of selective attention in people with aphasia (PWA) is currently unknown. Selective attention is essential for everyday communication, and inhibition is an important part of selective attention. This study explored components of inhibition--both intentional and reactive inhibition--during spoken-word production in PWA and in…

Reactive power compensating system

DOEpatents

Williams, Timothy J.; El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.

1987-01-01

The reactive power of an induction machine is compensated by providing fixed capacitors on each phase line for the minimum compensation required, sensing the current on one line at the time its voltage crosses zero to determine the actual compensation required for each phase, and selecting switched capacitors on each line to provide the balance of the compensation required.

Cardiac Reactivity and Stimulant Use in Adolescents with Autism Spectrum Disorders with Comorbid ADHD Versus ADHD

ERIC Educational Resources Information Center

Bink, M.; Popma, A.; Bongers, I. L.; van Boxtel, G. J. M.; Denissen, A.; van Nieuwenhuizen, Ch.

2015-01-01

A large number of youngsters with autism spectrum disorders (ASD) display comorbid attention deficit/hyperactivity disorder (ADHD) symptoms. However, previous studies are not conclusive whether psychophysiological correlates, like cardiac reactivity, are different for ASD with comorbid ADHD (ASD+) compared to ADHD. Therefore, the current study…

Anxiety Symptoms Account for the Link between Reactive Aggression and Sleep Problems among Latino Adolescents

ERIC Educational Resources Information Center

Fite, Paula J.; Becker, Stephen P.; Rubens, Sonia L.; Cheatham-Johnson, Randi

2015-01-01

Background: Sleep problems are common among adolescents and have a negative impact on functioning. A better understanding of factors that contribute to sleep problems in adolescence can help guide more effective, targeted interventions. Objective: The current study examined the associations between reactive and proactive functions of aggression…

Online Assessment of Voltage Stability in Power Systems with PMUs

NASA Astrophysics Data System (ADS)

Chitare, Prasad Bhagwat; Murthy Balijepalli, V. S. K.; Khaparde, S. A.

2013-05-01

Abstract: For the assessment of voltage instability which comprises the detection of voltage instability and identification of critical buses, two indices namely, system wide Qtax, and bus-specific qtax, are proposed. The Qtax, based on the sensitivity of the reactive power injections to the loading in the system provides early detection of impending voltage instability. The computed qtax indices identify the critcal buses among the load buses in the system. The identified critical buses provided optimal lacations for the corrective control actions for averting voltage instability. Additionally, for voltage stability monitoring, determining the poing of exhaustion of the reactive reserves in system is also crucial. This is addressed by proposed Q-Monitoring Index (QMI), which is the ratio of the reactive component of the source current to the sink current that flows through the adjacent transmission line. These proposed indices together can provide early indication to impending voltage instability. This has been illustrated on IEEE-39 bus system. The reactive support on identified critical buses results in maximum increase in the loadability of the system.

Integrating between-host transmission and within-host immunity to analyze the impact of varicella vaccination on zoster

PubMed Central

Ogunjimi, Benson; Willem, Lander; Beutels, Philippe; Hens, Niel

2015-01-01

Varicella-zoster virus (VZV) causes chickenpox and reactivation of latent VZV causes herpes zoster (HZ). VZV reactivation is subject to the opposing mechanisms of declining and boosted VZV-specific cellular mediated immunity (CMI). A reduction in exogenous re-exposure ‘opportunities’ through universal chickenpox vaccination could therefore lead to an increase in HZ incidence. We present the first individual-based model that integrates within-host data on VZV-CMI and between-host transmission data to simulate HZ incidence. This model allows estimating currently unknown pivotal biomedical parameters, including the duration of exogenous boosting at 2 years, with a peak threefold to fourfold increase of VZV-CMI; the VZV weekly reactivation probability at 5% and VZV subclinical reactivation having no effect on VZV-CMI. A 100% effective chickenpox vaccine given to 1 year olds would cause a 1.75 times peak increase in HZ 31 years after implementation. This increase is predicted to occur mainly in younger age groups than is currently assumed. DOI: http://dx.doi.org/10.7554/eLife.07116.001 PMID:26259874

Improving the Energy Market: Algorithms, Market Implications, and Transmission Switching

NASA Astrophysics Data System (ADS)

Lipka, Paula Ann

This dissertation aims to improve ISO operations through a better real-time market solution algorithm that directly considers both real and reactive power, finds a feasible Alternating Current Optimal Power Flow solution, and allows for solving transmission switching problems in an AC setting. Most of the IEEE systems do not contain any thermal limits on lines, and the ones that do are often not binding. Chapter 3 modifies the thermal limits for the IEEE systems to create new, interesting test cases. Algorithms created to better solve the power flow problem often solve the IEEE cases without line limits. However, one of the factors that makes the power flow problem hard is thermal limits on the lines. The transmission networks in practice often have transmission lines that become congested, and it is unrealistic to ignore line limits. Modifying the IEEE test cases makes it possible for other researchers to be able to test their algorithms on a setup that is closer to the actual ISO setup. This thesis also examines how to convert limits given on apparent power---as is in the case in the Polish test systems---to limits on current. The main consideration in setting line limits is temperature, which linearly relates to current. Setting limits on real or apparent power is actually a proxy for using the limits on current. Therefore, Chapter 3 shows how to convert back to the best physical representation of line limits. A sequential linearization of the current-voltage formulation of the Alternating Current Optimal Power Flow (ACOPF) problem is used to find an AC-feasible generator dispatch. In this sequential linearization, there are parameters that are set to the previous optimal solution. Additionally, to improve accuracy of the Taylor series approximations that are used, the movement of the voltage is restricted. The movement of the voltage is allowed to be very large at the first iteration and is restricted further on each subsequent iteration, with the restriction corresponding to the accuracy and AC-feasiblity of the solution. This linearization was tested on the IEEE and Polish systems, which range from 14 to 3375 buses and 20 to 4161 transmission lines. It had an accuracy of 0.5% or less for all but the 30-bus system. It also solved in linear time with CPLEX, while the non-linear version solved in O(n1.11) to O(n1.39). The sequential linearization is slower than the nonlinear formulation for smaller problems, but faster for larger problems, and its linear computational time means it would continue solving faster for larger problems. A major consideration to implementing algorithms to solve the optimal generator dispatch is ensuring that the resulting prices from the algorithm will support the market. Since the sequential linearization is linear, it is convex, its marginal values are well-defined, and there is no duality gap. The prices and settlements obtained from the sequential linearization therefore can be used to run a market. This market will include extra prices and settlements for reactive power and voltage, compared to the present-day market, which is based on real power. An advantage of this is that there is a very clear pool that can be used for reactive power/voltage support payments, while presently there is not a clear pool to take them out of. This method also reveals how valuable reactive power and voltage are at different locations, which can enable better planning of reactive resource construction. Transmission switching increases the feasible region of the generator dispatch, which means there may be a better solution than without transmission switching. Power flows on transmission lines are not directly controllable; rather, the power flows according to how it is injected and the physical characteristics of the lines. Changing the network topology changes the physical characteristics, which changes the flows. This means that sets of generator dispatch that may have previously been infeasible due to the flow exceeding line constraints may be feasible, since the flows will be different and may meet line constraints. However, transmission switching is a mixed integer problem, which may have a very slow solution time. For economic switching, we examine a series of heuristics. We examine the congestion rent heuristic in detail and then examine many other heuristics at a higher level. Post-contingency corrective switching aims to fix issues in the power network after a line or generator outage. In Chapter 7, we show that using the sequential linear program with corrective switching helps solve voltage and excessive flow issues. (Abstract shortened by UMI.).

Auditory feedback blocks memory benefits of cueing during sleep

PubMed Central

Schreiner, Thomas; Lehmann, Mick; Rasch, Björn

2015-01-01

It is now widely accepted that re-exposure to memory cues during sleep reactivates memories and can improve later recall. However, the underlying mechanisms are still unknown. As reactivation during wakefulness renders memories sensitive to updating, it remains an intriguing question whether reactivated memories during sleep also become susceptible to incorporating further information after the cue. Here we show that the memory benefits of cueing Dutch vocabulary during sleep are in fact completely blocked when memory cues are directly followed by either correct or conflicting auditory feedback, or a pure tone. In addition, immediate (but not delayed) auditory stimulation abolishes the characteristic increases in oscillatory theta and spindle activity typically associated with successful reactivation during sleep as revealed by high-density electroencephalography. We conclude that plastic processes associated with theta and spindle oscillations occurring during a sensitive period immediately after the cue are necessary for stabilizing reactivated memory traces during sleep. PMID:26507814

Atypical Reactivity of Heart Rate Variability to Stress and Depression: Systematic Review of the Literature and Directions for Future Research

PubMed Central

Hamilton, Jessica L.; Alloy, Lauren B.

2017-01-01

Heart rate variability has received growing attention in the depression literature, with several recent meta-analyses indicating that lower resting heart rate variability is associated with depression. However, the role of fluctuations in heart rate variability (or reactivity) in response to stress in depression remains less clear. The present review provides a systematic examination of the literature on heart rate variability reactivity to a laboratory-induced stressor task and depression, including 26 studies of reactivity in heart rate variability and clinical depression, remitted (or history of) depression, and subthreshold depression (or symptom-level depression) among adults, adolescents, and children. In addition to reviewing the findings of these studies, methodological considerations and conceptual gaps in the literature are addressed. We conclude by highlighting the importance of investigating the potential transactional relationship between heart rate variability reactivity and depression and possible mechanisms underlying this relationship. PMID:27697746

The atom-molecule reaction D plus H2 yields HD plus H studied by molecular beams

NASA Technical Reports Server (NTRS)

Geddes, J.; Krause, H. F.; Fite, W. L.

1972-01-01

Collisions between deuterium atoms and hydrogen molecules were studied in a modulated crossed beam experiment. The relative signal intensity and the signal phase for the product HD from reactive collisions permitted determination of both the angular distribution and HD mean velocity as a function of angle. From these a relative differential reactive scattering cross section in center-of-mass coordinates was deduced. The experiment indicates that reactively formed HD which has little or no internal excitation departs from the collision anisotropically, with maximum amplitude 180 deg from the direction of the incident D beam in center-of-mass coordinates, which shows that the D-H-H reacting configuration is short-lived compared to its rotation time. Non reactive scattering of D by H2 was used to assign absolute values to the differential reactive scattering cross sections.

Current posttraumatic stress disorder and exaggerated threat sensitivity associated with elevated inflammation in the Mind Your Heart Study.

PubMed

O'Donovan, Aoife; Ahmadian, Ashkan J; Neylan, Thomas C; Pacult, Mark A; Edmondson, Donald; Cohen, Beth E

2017-02-01

Elevated inflammation has been repeatedly observed in posttraumatic stress disorder (PTSD), and it may drive the development of both psychiatric symptoms and physical comorbidities. However, it is not clear if elevated inflammation is a feature of both remitted and current PTSD, and little is known about relationships between specific clusters of PTSD symptoms and inflammation. Exaggerated threat sensitivity, as indexed by threat reactivity and avoidance of perceived threats, may be particularly closely associated with inflammation. We assessed PTSD symptoms and threat sensitivity using the Clinician Administered PTSD Scale in 735 Veterans Affairs patients (35% current PTSD; 16% remitted PTSD) who participated in the Mind Your Heart Study (mean age=59±11; 94% male). High sensitivity C-reactive protein (hsCRP), white blood cell count (WBC), and fibrinogen were used as indices of inflammation. Analysis of covariance models with planned contrasts were used to examine differences in inflammation by PTSD status, adjusting for age, sex, race, kidney function and socioeconomic status. Individuals with current PTSD had significantly higher hsCRP and WBC than patients with no history of PTSD, but there were no significant differences in inflammatory markers between those with remitted versus no history of PTSD. Within patients with current PTSD, higher threat reactivity was independently associated with higher hsCRP (β=0.16, p=0.01) and WBC count (β=0.24, <0.001), and higher effortful avoidance was associated with higher fibrinogen (β=0.13, p=0.04). Our data indicate that elevated inflammation may be a feature of current, but not remitted, PTSD. Within patients with PTSD, higher threat reactivity was also associated with elevated inflammation. A better understanding of the relationship between threat sensitivity and inflammation may inform interventions for patients with PTSD. Copyright © 2016 Elsevier Inc. All rights reserved.

Long term effects of childhood trauma on cortisol stress reactivity in adulthood and relationship to the occurrence of depression.

PubMed

Suzuki, Akiko; Poon, Lucia; Papadopoulos, Andrew S; Kumari, Veena; Cleare, Anthony J

2014-12-01

Childhood trauma may have longstanding effects on individuals' propensity to react adversely to stress, and also predisposes individuals to suffer from depression. The current study aimed to examine stress reactivity in individuals with and without a history of childhood trauma by measuring cortisol responses to the passive viewing of stressful images, specifically including images relevant to childhood trauma. In addition, participants with and without a diagnosis of current depression were studied to investigate whether cortisol stress reactivity may underlie resilience or vulnerability to depression. The study involved 17 healthy participants with and 24 without a history of childhood trauma; and 21 depressed patients with and 18 without a history of childhood trauma. Salivary cortisol was measured before, during and after participants were shown affectively laden images, including standardised scenes from the International Affective Picture System and also images suggestive of childhood abuse. Cortisol stress reactivity to the passive image viewing was compared between groups. In those who had experienced childhood trauma, cortisol stress responses were overall low and the same in those who were depressed and those who were not (mean stress reactivity variable - depressed: 0.8 nmol/l; non-depressed: 0.72 nmol/l). In contrast, cortisol stress reactivity was raised in depressed subjects relative to those who were not depressed in those without a history of childhood trauma (mean stress reactivity variable - depressed: 3.75 nmol/l; non-depressed: 0.1 nmol/l). A history of childhood trauma has longstanding effects on adulthood cortisol responses to stress, particularly in that depressed individuals with a history of childhood trauma show blunted cortisol responses. However, there were no differences between abused depressed and abused non-depressed subjects on cortisol stress responses, suggesting that such a finding does not explain subsequent susceptibility to depression. On the other hand, patients who experience depression without a history of childhood trauma show enhanced cortisol stress reactivity, which could help explain the aetiology of their depressive illnesses. Differences between the current findings and those using other pharmacological and stress challenge paradigms may relate to the type of stimuli used and to dysfunction at different levels of the hypothalamic-pituitary-adrenal (HPA) axis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dual properties of a hydrogen oxidation Ni-catalyst entrapped within a polymer promote self-defense against oxygen

DOE PAGES

Oughli, Alaa A.; Ruff, Adrian; Boralugodage, Nilusha Priyadarshani; ...

2018-02-28

A bio-inspired O 2 sensitive nickel catalyst dispersed in a hydrophobic and redox-silent polymer matrix shows enhanced stability for catalytic H 2 oxidation as well as O 2 tolerance. A simple but efficient electrode design separates the catalyst into two different reaction layers to promote different reactivity on the catalyst. (1) close to the electrode surface, the catalyst can directly exchange electrons with the electrode and generate current from H 2 oxidation; and (2) at the outer film boundary, the electrolyte exposed layer is electrically isolated from the electrode, which enables the H 2 reduced Ni-complex to convert O 2more » to H 2O and thus provides protection to the O 2-sensitive inner reaction layer. This strategy solves one of the biggest limitations of these otherwise outstanding catalysts and could be used to protect other similar catalysts whose wider application is currently limited by sensitivity towards oxygen.« less

Neurological Effects of Honey: Current and Future Prospects

PubMed Central

Mijanur Rahman, Mohammad; Gan, Siew Hua; Khalil, Md. Ibrahim

2014-01-01

Honey is the only insect-derived natural product with therapeutic, traditional, spiritual, nutritional, cosmetic, and industrial value. In addition to having excellent nutritional value, honey is a good source of physiologically active natural compounds, such as polyphenols. Unfortunately, there are very few current research projects investigating the nootropic and neuropharmacological effects of honey, and these are still in their early stages. Raw honey possesses nootropic effects, such as memory-enhancing effects, as well as neuropharmacological activities, such as anxiolytic, antinociceptive, anticonvulsant, and antidepressant activities. Research suggests that the polyphenol constituents of honey can quench biological reactive oxygen species and counter oxidative stress while restoring the cellular antioxidant defense system. Honey polyphenols are also directly involved in apoptotic activities while attenuating microglia-induced neuroinflammation. Honey polyphenols are useful in improving memory deficits and can act at the molecular level. Therefore, the ultimate biochemical impact of honey on specific neurodegenerative diseases, apoptosis, necrosis, neuroinflammation, synaptic plasticity, and behavior-modulating neural circuitry should be evaluated with appropriate mechanistic approaches using biochemical and molecular tools. PMID:24876885

Deep silicon etching: current capabilities and future directions

NASA Astrophysics Data System (ADS)

Westerman, Russ; Martinez, Linnell; Pays-Volard, David; Mackenzie, Ken; Lazerand, Thierry

2014-03-01

Deep Reactive Ion Etching (DRIE) has revolutionized a wide variety of MEMS applications since its inception nearly two decades ago. The DRIE technology has been largely responsible for allowing lab scale technology demonstrations to become manufacturable and profitable consumer products. As applications which utilize DRIE technologies continue to expand and evolve, they continue to spawn a range of new requirements and open up exciting opportunities for advancement of DRIE. This paper will examine a number of current and emerging DRIE applications including nanotechnology, and DRIE related packaging technologies such as Through Silicon Via (TSV) and plasma dicing. The paper will discuss a number of technical challenges and solutions associated with these applications including: feature profile control at high aspect ratios, causes and elimination of feature tilt/skew, process options for fragile device structures, and problems associated with through substrate etching. The paper will close with a short discussion around the challenges of implementing DRIE in production environments as well as looking at potentially disruptive enhancements / substitutions for DRIE.

Dual properties of a hydrogen oxidation Ni-catalyst entrapped within a polymer promote self-defense against oxygen

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

Oughli, Alaa A.; Ruff, Adrian; Boralugodage, Nilusha Priyadarshani

A bio-inspired O 2 sensitive nickel catalyst dispersed in a hydrophobic and redox-silent polymer matrix shows enhanced stability for catalytic H 2 oxidation as well as O 2 tolerance. A simple but efficient electrode design separates the catalyst into two different reaction layers to promote different reactivity on the catalyst. (1) close to the electrode surface, the catalyst can directly exchange electrons with the electrode and generate current from H 2 oxidation; and (2) at the outer film boundary, the electrolyte exposed layer is electrically isolated from the electrode, which enables the H 2 reduced Ni-complex to convert O 2more » to H 2O and thus provides protection to the O 2-sensitive inner reaction layer. This strategy solves one of the biggest limitations of these otherwise outstanding catalysts and could be used to protect other similar catalysts whose wider application is currently limited by sensitivity towards oxygen.« less

Self-organised synthesis of Rh nanostructures with tunable chemical reactivity

PubMed Central

2007-01-01

Nonequilibrium periodic nanostructures such as nanoscale ripples, mounds and rhomboidal pyramids formed on Rh(110) are particularly interesting as candidate model systems with enhanced catalytic reactivity, since they are endowed with steep facets running along nonequilibrium low-symmetry directions, exposing a high density of undercoordinated atoms. In this review we report on the formation of these novel nanostructured surfaces, a kinetic process which can be controlled by changing parameters such as temperature, sputtering ion flux and energy. The role of surface morphology with respect to chemical reactivity is investigated by analysing the carbon monoxide dissociation probability on the different nanostructured surfaces.

Preparation and study of Titanium Nitride films by reactive sputtering and an investigation of target poisoning during the process

NASA Astrophysics Data System (ADS)

Aziz, Tareque; Rumaiz, Abdul

Titanium Nitride (TiNx) thin films were prepared by reactive dc sputtering in presence of Ar-N2 plasma. The thin films were grown on Quartz and pure Si surfaces. The Ar-N2 content ratio was gradually varied while the substrate and the Titanium target were kept at room temperature. Structural properties, optical and electrical properties of the thin films were studied by using X-ray Photoelectron Spectroscopy (XPS) and XRD and 4 probe resistivity measurement. Target poisoning of the Ti target was also studied by varying reactive gas concentration and measuring the target current. A study of target current vs growth rate of the films was performed to investigate the onset of ``poison'' mode.Although there was an insignificant drop in plasma current, we noticed a drop in the deposition rate. This result was tested against Monte Carlo simulations using SRIM simulations. Effects of annealing on the crystallinity and the sheet resistance will also be discussed. The work has been supported by BSA,DOE.

Solvent recyclability in a multistep direct liquefaction process

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

Hetland, M.D.; Rindt, J.R.

1995-12-31

Direct liquefaction research at the Energy & Environmental Research Center (EERC) has, for a number of years, concentrated on developing a direct liquefaction process specifically for low-rank coals (LRCs) through the use of hydrogen-donating solvents and solvents similar to coal-derived liquids, the water/gas shift reaction, and lower-severity reaction conditions. The underlying assumption of all of the research was that advantage could be taken of the reactivity and specific qualities of LRCs to produce a tetrahydrofuran (THF)-soluble material that might be easier to upgrade than the soluble residuum produced during direct liquefaction of high-rank coals. A multistep approach was taken tomore » produce the THF-soluble material, consisting of (1) preconversion treatment to prepare the coal for solubilization, (2) solubilization of the coal in the solvent, and (3) polishing to complete solubilization of the remaining material. The product of these three steps can then be upgraded during a traditional hydrotreatment step. The results of the EERC`s research indicated that additional studies to develop this process more fully were justified. Two areas were targeted for further research: (1) determination of the recyclability of the solvent used during solubilization and (2) determination of the minimum severity required for hydrotreatment of the liquid product. The current project was funded to investigate these two areas.« less

Unsaturated fatty acids show clear elicitation responses in a modified local lymph node assay with an elicitation phase, and test positive in the direct peptide reactivity assay.

PubMed

Yamashita, Kunihiko; Shinoda, Shinsuke; Hagiwara, Saori; Miyazaki, Hiroshi; Itagaki, Hiroshi

2015-12-01

The Organisation for Economic Co-operation and Development (OECD) Test Guidelines (TG) adopted the murine local lymph node assay (LLNA) and guinea pig maximization test (GPMT) as stand-alone skin sensitization test methods. However, unsaturated carbon-carbon double-bond and/or lipid acids afforded false-positive results more frequently in the LLNA compared to those in the GPMT and/or in human subjects. In the current study, oleic, linoleic, linolenic, undecylenic, fumaric, maleic, and succinic acid and squalene were tested in a modified LLNA with an elicitation phase (LLNA:DAE), and in a direct peptide reactivity assay (DPRA) to evaluate their skin-sensitizing potential. Oleic, linoleic, linolenic, undecylenic and maleic acid were positive in the LLNA:DAE, of which three, linoleic, linolenic, and maleic acid were positive in the DPRA. Furthermore, the results of the cross-sensitizing tests using four LLNA:DAE-positive chemicals were negative, indicating a chemical-specific elicitation response. In a previous report, the estimated concentration needed to produce a stimulation index of 3 (EC3) of linolenic acid, squalene, and maleic acid in the LLNA was < 10%. Therefore, these chemicals were classified as moderate skin sensitizers in the LLNA. However, the skin-sensitizing potential of all LLNA:DAE-positive chemicals was estimated as weak. These results suggested that oleic, linoleic, linolenic, undecylenic, and maleic acid had skin-sensitizing potential, and that the LLNA overestimated the skin-sensitizing potential compared to that estimated by the LLNA:DAE.

Effect of steady-state methadone on high fructose corn syrup consumption in rats.

PubMed

Daniels, Stephen; Pratt, Mick; Zhou, Yan; Leri, Francesco

2018-02-01

Patients undergoing methadone maintenance treatment self-report enhanced preferences for, and excessive consumption of, foods rich in sugar. However, it is unclear whether these are direct pharmacological effects of methadone or the consequences of metabolic dysfunctions induced by addiction to illicit opiates. Hence, the current study in drug-naïve male Sprague-Dawley rats explored the effects of steady-state methadone delivered by osmotic mini-pumps (13 days; 0, 10, 30 mg/kg/day) on consumption of rat chow and a palatable, sweet, liquid high fructose corn syrup solution. Six days after the removal of the pumps, mRNA expression of genes involved in responses to stress and rewards were quantified: pro-opiomelanocortin in the hypothalamus, mu-opioid receptor in the nucleus accumbens, and dopamine D2 receptor in the dorsal striatum. Taste reactivity and locomotion tests were also performed throughout the study. It was found that methadone increased caloric intake from high fructose corn syrup and reduced caloric intake from chow, effects that could not be directly ascribed to changes in high fructose corn syrup taste reactivity or motor functions. However, the changes in caloric intake displayed significant tolerance, and mRNA expression analysis suggested that methadone attenuated the effect of high fructose corn syrup on pro-opiomelanocortin mRNA, and possibly on dopamine D2 receptor mRNA. These findings in rats suggest that the pharmacological effect of methadone, administered to achieve steady-state maintenance, may not be the primary cause of dietary alterations reported by patients maintained on methadone.

Unifying Model-Based and Reactive Programming within a Model-Based Executive

NASA Technical Reports Server (NTRS)

Williams, Brian C.; Gupta, Vineet; Norvig, Peter (Technical Monitor)

1999-01-01

Real-time, model-based, deduction has recently emerged as a vital component in AI's tool box for developing highly autonomous reactive systems. Yet one of the current hurdles towards developing model-based reactive systems is the number of methods simultaneously employed, and their corresponding melange of programming and modeling languages. This paper offers an important step towards unification. We introduce RMPL, a rich modeling language that combines probabilistic, constraint-based modeling with reactive programming constructs, while offering a simple semantics in terms of hidden state Markov processes. We introduce probabilistic, hierarchical constraint automata (PHCA), which allow Markov processes to be expressed in a compact representation that preserves the modularity of RMPL programs. Finally, a model-based executive, called Reactive Burton is described that exploits this compact encoding to perform efficIent simulation, belief state update and control sequence generation.

Influence of inert gases on the reactive high power pulsed magnetron sputtering process of carbon-nitride thin films

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

Schmidt, Susann; Czigany, Zsolt; Greczynski, Grzegorz

2013-01-15

The influence of inert gases (Ne, Ar, Kr) on the sputter process of carbon and carbon-nitride (CN{sub x}) thin films was studied using reactive high power pulsed magnetron sputtering (HiPIMS). Thin solid films were synthesized in an industrial deposition chamber from a graphite target. The peak target current during HiPIMS processing was found to decrease with increasing inert gas mass. Time averaged and time resolved ion mass spectroscopy showed that the addition of nitrogen, as reactive gas, resulted in less energetic ion species for processes employing Ne, whereas the opposite was noticed when Ar or Kr were employed as inertmore » gas. Processes in nonreactive ambient showed generally lower total ion fluxes for the three different inert gases. As soon as N{sub 2} was introduced into the process, the deposition rates for Ne and Ar-containing processes increased significantly. The reactive Kr-process, in contrast, showed slightly lower deposition rates than the nonreactive. The resulting thin films were characterized regarding their bonding and microstructure by x-ray photoelectron spectroscopy and transmission electron microscopy. Reactively deposited CN{sub x} thin films in Ar and Kr ambient exhibited an ordering toward a fullerene-like structure, whereas carbon and CN{sub x} films deposited in Ne atmosphere were found to be amorphous. This is attributed to an elevated amount of highly energetic particles observed during ion mass spectrometry and indicated by high peak target currents in Ne-containing processes. These results are discussed with respect to the current understanding of the structural evolution of a-C and CN{sub x} thin films.« less

Detection of radiation-induced changes in electrochemical properties of austenitic stainless steels using miniaturized specimens and the single-loop electrochemical potentiokinetic reactivation method

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

Inazumi, T.; Bell, G.E.C.; Kenik, E.A.

1993-01-01

Single-loop electrochemical potentiokinetic reactivation testing of miniaturized (TEM) specimens can provide reliable data comparable to data obtained with larger specimens. Significant changes in electrochemical properties (increased reactivation current and Flade potential) were detected for PCA and type 316 stainless steels irradiated at 200--420[degrees]C up to 7--9 dpa. Irradiations in the FFTF Materials Open Test Assembly and in the Oak Ridge Research Reactor are reported on. 45 figs., 5 tabs., 52 refs.

Detection of radiation-induced changes in electrochemical properties of austenitic stainless steels using miniaturized specimens and the single-loop electrochemical potentiokinetic reactivation method

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

Inazumi, T.; Bell, G.E.C.; Kenik, E.A.

1993-01-01

Single-loop electrochemical potentiokinetic reactivation testing of miniaturized (TEM) specimens can provide reliable data comparable to data obtained with larger specimens. Significant changes in electrochemical properties (increased reactivation current and Flade potential) were detected for PCA and type 316 stainless steels irradiated at 200--420{degrees}C up to 7--9 dpa. Irradiations in the FFTF Materials Open Test Assembly and in the Oak Ridge Research Reactor are reported on. 45 figs., 5 tabs., 52 refs.

The ReaxFF reactive force-field: Development, applications, and future directions

DOE PAGES

Senftle, Thomas; Hong, Sungwook; Islam, Md Mahbubul; ...

2016-03-04

The reactive force-field (ReaxFF) interatomic potential is a powerful computational tool for exploring, developing and optimizing material properties. Methods based on the principles of quantum mechanics (QM), while offering valuable theoretical guidance at the electronic level, are often too computationally intense for simulations that consider the full dynamic evolution of a system. Alternatively, empirical interatomic potentials that are based on classical principles require significantly fewer computational resources, which enables simulations to better describe dynamic processes over longer timeframes and on larger scales. Such methods, however, typically require a predefined connectivity between atoms, precluding simulations that involve reactive events. The ReaxFFmore » method was developed to help bridge this gap. Approaching the gap from the classical side, ReaxFF casts the empirical interatomic potential within a bond-order formalism, thus implicitly describing chemical bonding without expensive QM calculations. As a result, this article provides an overview of the development, application, and future directions of the ReaxFF method.« less

The Benefits of Targeted Memory Reactivation for Consolidation in Sleep are Contingent on Memory Accuracy and Direct Cue-Memory Associations

PubMed Central

Cairney, Scott A.; Lindsay, Shane; Sobczak, Justyna M.; Paller, Ken A.; Gaskell, M. Gareth

2016-01-01

Study Objectives: To investigate how the effects of targeted memory reactivation (TMR) are influenced by memory accuracy prior to sleep and the presence or absence of direct cue-memory associations. Methods: 30 participants associated each of 50 pictures with an unrelated word and then with a screen location in two separate tasks. During picture-location training, each picture was also presented with a semantically related sound. The sounds were therefore directly associated with the picture locations but indirectly associated with the words. During a subsequent nap, half of the sounds were replayed in slow wave sleep (SWS). The effect of TMR on memory for the picture locations (direct cue-memory associations) and picture-word pairs (indirect cue-memory associations) was then examined. Results: TMR reduced overall memory decay for recall of picture locations. Further analyses revealed a benefit of TMR for picture locations recalled with a low degree of accuracy prior to sleep, but not those recalled with a high degree of accuracy. The benefit of TMR for low accuracy memories was predicted by time spent in SWS. There was no benefit of TMR for memory of the picture-word pairs, irrespective of memory accuracy prior to sleep. Conclusions: TMR provides the greatest benefit to memories recalled with a low degree of accuracy prior to sleep. The memory benefits of TMR may also be contingent on direct cue-memory associations. Citation: Cairney SA, Lindsay S, Sobczak JM, Paller KA, Gaskell MG. The benefits of targeted memory reactivation for consolidation in sleep are contingent on memory accuracy and direct cue-memory associations. SLEEP 2016;39(5):1139–1150. PMID:26856905

The Impact of Transformer Winding Connections of A Grid-Connected PV on Voltage Quality Improvement

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

Muljadi, Eduard; Tumbelaka, Hanny H.; Gao, Wenzhong

In this paper, the high-power PV plant is connected to the weak grid by means of a three-phase power transformer. The selection of transformer winding connection is critical especially when the PV inverter has a reactive power controller. In general, transformer winding connection can be arranged in star-star (with neutral earthed) or star-delta. The reactive power controller supports voltage regulation of the power system particularly under transient faults. Its control strategy is based on utilizing the grid currents to make a three-phase reactive unbalanced current with a small gain. The gain is determined by the system impedance. Simulation results exhibitmore » that the control strategy works very well particularly under disturbance conditions when the transformer winding connection is star-star with both neutrals grounded. The power quality in terms of the voltage quality is improved.« less

Sleep deprivation affects reactivity to positive but not negative stimuli.

PubMed

Pilcher, June J; Callan, Christina; Posey, J Laura

2015-12-01

The current study examined the effects of partial and total sleep deprivation on emotional reactivity. Twenty-eight partially sleep-deprived participants and 31 totally sleep-deprived participants rated their valence and arousal responses to positive and negative pictures across four testing sessions during the day following partial sleep deprivation or during the night under total sleep deprivation. The results suggest that valence and arousal ratings decreased under both sleep deprivation conditions. In addition, partial and total sleep deprivation had a greater negative effect on positive events than negative events. These results suggest that sleep-deprived persons are more likely to respond less to positive events than negative events. One explanation for the current findings is that negative events could elicit more attentive behavior and thus stable responding under sleep deprivation conditions. As such, sleep deprivation could impact reactivity to emotional stimuli through automated attentional and self-regulatory processes. Copyright © 2015 Elsevier Inc. All rights reserved.

The Relation between Salivary Cortisol, Callous-Unemotional Traits, and Conduct Problems in an Adolescent Non-Referred Sample

ERIC Educational Resources Information Center

Loney, Bryan R.; Butler, Melanie A.; Lima, Elizabeth N.; Counts, Carla A.; Eckel, Lisa A.

2006-01-01

Background: Previous research has suggested that adult psychopathic behavior and child callous-unemotional (CU) traits are uniquely related to low emotional reactivity. Salivary cortisol is a promising biological measure of emotional reactivity that has been relatively overlooked in research on CU traits and antisocial behavior. The current study…

Gender Differences in Psychopathic Traits, Types, and Correlates of Aggression among Adjudicated Youth

ERIC Educational Resources Information Center

Stickle, Timothy R.; Marini, Victoria A.; Thomas, Jamila N.

2012-01-01

The current study investigated gender differences in types and correlates of aggression among 150 adjudicated youth (M age = 15.2, SD = 1.4). In cluster analysis, consistent with past studies, one aggressive group characterized by moderate levels of reactive aggression and one characterized by high levels of proactive and reactive aggression…

Profiles of Disruptive Behavior across Early Childhood: Contributions of Frustration Reactivity, Physiological Regulation, and Maternal Behavior

ERIC Educational Resources Information Center

Degnan, Kathryn A.; Calkins, Susan D.; Keane, Susan P.; Hill-Soderlund, Ashley L.

2008-01-01

Disruptive behavior, including aggression, defiance, and temper tantrums, typically peaks in early toddlerhood and decreases by school entry; however, some children do not show this normative decline. The current study examined disruptive behavior in 318 boys and girls at 2, 4, and 5 years of age and frustration reactivity, physiological…

The Role of Child Temperament on Low-Income Preschool Children's Relationships with Their Parents and Teachers

ERIC Educational Resources Information Center

Acar, Ibrahim H.; Torquati, Julia C.; Encinger, Amy; Colgrove, Amy

2018-01-01

The current study examined the associations between low-income preschool children's temperament (reactive and regulatory) and their relationships with parents and teachers. In particular, we focused on the moderating role of regulatory temperament on reactive temperament in the prediction of closeness and conflict with parents and teachers. Two…

Associations between Effortful Control, Psychological Control and Proactive and Reactive Aggression

ERIC Educational Resources Information Center

Rathert, Jamie; Fite, Paula J.; Gaertner, Alden E.

2011-01-01

The current study examined relations between effortful control (ones ability to focus and shift attention in an adaptive manner), psychological control (caregiver attempts to manipulate the child's internal world) and proactive and reactive aggression. Participants were 69 children (54% male) ranging from 9 to 12 years of age (M = 10.35, SD =…

Influence of Perceived Neighborhood Safety on Proactive and Reactive Aggression

ERIC Educational Resources Information Center

Fite, Paula J.; Vitulano, Michael; Wynn, Porche'; Wimsatt, Amber; Gaertner, Alden; Rathert, Jamie

2010-01-01

The current study examined associations between perceived neighborhood safety and proactive and reactive subtypes of aggression while also considering peer delinquency and poor parental monitoring in a community recruited sample of 89 children (56% male) ranging from 9 to 12 years of age (M=10.44, SD=1.14). In addition, neighborhood safety was…

In Vitro Ability of Currently Available Oximes to Reactivate Organophosphate Pesticide-Inhibited Human Acetylcholinesterase and Butyrylcholinesterase

PubMed Central

Jun, Daniel; Musilova, Lucie; Musilek, Kamil; Kuca, Kamil

2011-01-01

We have in vitro tested the ability of common, commercially available, cholinesterase reactivators (pralidoxime, obidoxime, methoxime, trimedoxime and HI-6) to reactivate human acetylcholinesterase (AChE), inhibited by five structurally different organophosphate pesticides and inhibitors (paraoxon, dichlorvos, DFP, leptophos-oxon and methamidophos). We also tested reactivation of human butyrylcholinesterase (BChE) with the aim of finding a potent oxime, suitable to serve as a “pseudocatalytic” bioscavenger in combination with this enzyme. Such a combination could allow an increase of prophylactic and therapeutic efficacy of the administered enzyme. According to our results, the best broad-spectrum AChE reactivators were trimedoxime and obidoxime in the case of paraoxon, leptophos-oxon, and methamidophos-inhibited AChE. Methamidophos and leptophos-oxon were quite easily reactivatable by all tested reactivators. In the case of methamidophos-inhibited AChE, the lower oxime concentration (10−5 M) had higher reactivation ability than the 10−4 M concentration. Therefore, we evaluated the reactivation ability of obidoxime in a concentration range of 10−3–10−7 M. The reactivation of methamidophos-inhibited AChE with different obidoxime concentrations resulted in a bell shaped curve with maximum reactivation at 10−5 M. In the case of BChE, no reactivator exceeded 15% reactivation ability and therefore none of the oximes can be recommended as a candidate for “pseudocatalytic” bioscavengers with BChE. PMID:21673941

Evaluation of commercial enzyme-linked immunosorbent assays to identify psychedelic phenethylamines.

PubMed

Kerrigan, Sarah; Mellon, Monica Brady; Banuelos, Stephanie; Arndt, Crystal

2011-09-01

The 2C, 2C-T, and DO series of designer drugs pose a number of challenges to forensic toxicology laboratories. Although these drugs are seized by law enforcement agencies throughout the United States, they are not readily detected in forensic toxicology laboratories. A systematic evaluation of the cross-reactivity of 9 commercial enzyme-linked immunosorbent assays (ELISAs) was conducted using 11 designer drugs. Cross-reactivity was measured towards 2,5-dimethoxy-4-bromophenethylamine (2C-B), 2,5-dimethoxyphenethylamine (2C-H), 2,5-dimethoxy4-iodophenethylamine (2C-I), 2,5-dimethoxy-4ethylthiophenethylamine (2C-T-2), 2,5-dimethoxy-4isopropylthiophenethylamine (2C-T-4), 2,5-dimethoxy-4propylthiophenethylamine (2C-T-7), 2,5-dimethoxy-4bromoamphetamine (DOB), 2,5-dimethoxy-4-ethylamphetamine (DOET), 2,5-dimethoxy-4-iodoamphetamine (DOI), 2,5-dimethoxy-4-methylamphetamine (DOM), and 4methylthioamphetamine (4-MTA). Cross-reactivity towards the 2C, 2C-T, and DO series of psychedelic amphetamines was < 0.4%. Concentrations as high as 50,000 ng/mL in urine, which greatly exceed those expected in forensic case samples, were not sufficient to produce a positive result. The only substance to produce any measurable cross-reactivity was 4-MTA. Cross-reactivities of 5 and 7% were obtained using four methamphetamine/MDMA directed assays, 25 and 200% using two amphetamine-directed assays. The absence of any measurable cross-reactivity towards the 10 2C, 2C-T, and DO psychedelic phenethylamines makes it harder to detect these drugs using routine screening. As a consequence, laboratories that rely upon immunoassay rather than more broad spectrum chromatographic screening techniques, may fail to detect these powerful psychedelic substances.

Methods and apparatuses for reagent delivery, reactive barrier formation, and pest control

DOEpatents

Gilmore, Tyler [Pasco, WA; Kaplan, Daniel I [Aiken, SC; Last, George [Richland, WA

2002-07-09

A reagent delivery method includes positioning reagent delivery tubes in contact with soil. The tubes can include a wall that is permeable to a soil-modifying reagent. The method further includes supplying the reagent in the tubes, diffusing the reagent through the permeable wall and into the soil, and chemically modifying a selected component of the soil using the reagent. The tubes can be in subsurface contact with soil, including groundwater, and can be placed with directional drilling equipment independent of groundwater well casings. The soil-modifying reagent includes a variety of gases, liquids, colloids, and adsorbents that may be reactive or non-reactive with soil components. The method may be used inter alia to form reactive barriers, control pests, and enhance soil nutrients for microbes and plants.

Glow discharge plasma deposition of thin films

DOEpatents

Weakliem, Herbert A.; Vossen, Jr., John L.

1984-05-29

A glow discharge plasma reactor for deposition of thin films from a reactive RF glow discharge is provided with a screen positioned between the walls of the chamber and the cathode to confine the glow discharge region to within the region defined by the screen and the cathode. A substrate for receiving deposition material from a reactive gas is positioned outside the screened region. The screen is electrically connected to the system ground to thereby serve as the anode of the system. The energy of the reactive gas species is reduced as they diffuse through the screen to the substrate. Reactive gas is conducted directly into the glow discharge region through a centrally positioned distribution head to reduce contamination effects otherwise caused by secondary reaction products and impurities deposited on the reactor walls.

Ultrahigh vacuum process for the deposition of nanotubes and nanowires

DOEpatents

Das, Biswajit; Lee, Myung B

2015-02-03

A system and method A method of growing an elongate nanoelement from a growth surface includes: a) cleaning a growth surface on a base element; b) providing an ultrahigh vacuum reaction environment over the cleaned growth surface; c) generating a reactive gas of an atomic material to be used in forming the nanoelement; d) projecting a stream of the reactive gas at the growth surface within the reactive environment while maintaining a vacuum of at most 1.times.10.sup.-4 Pascal; e) growing the elongate nanoelement from the growth surface within the environment while maintaining the pressure of step c); f) after a desired length of nanoelement is attained within the environment, stopping direction of reactive gas into the environment; and g) returning the environment to an ultrahigh vacuum condition.

Cognitive-Affective Correlates of Suicide Ideation and Attempt: Mindfulness is Negatively Associated with Suicide Attempt History but Not State Suicidality.

PubMed

Chesin, Megan; Cascardi, Michele

2018-06-11

To test whether three cognitive-affective correlates, mindfulness, emotion reactivity, and depressive symptom severity, have different associations with current suicidal ideation (SI), a history of suicide attempt (SA) and SA+SI among emerging adults. To test whether impulsive-aggression (IA) moderates associations between cognitive-affective correlates of suicidal behavior and suicidality. Survey data on current SI, SA history, mindfulness, emotion reactivity, depressive symptom severity, and IA were collected from 780 emerging adults. Results from multinomial logistic regression analysis showed greater depressive symptom severity among emerging adults with current SI, regardless of SA history. Those with a history of SA reported greater depressive symptom severity and less mindfulness than controls. IA did not moderate relationships of SI and/or SA and mindfulness, emotion reactivity, or depressive symptom severity. Mindfulness is a marker of SA, and depressive symptom severity is associated with current SI and SA history in emerging adults. IA does not moderate these associations. To the extent that a history of SA is indicative of elevated trait-like suicide risk and SI indicates state suicidality, our findings suggest that mindfulness protects against longer-term vulnerability to SA while depressive symptom severity increases with increasing suicide state-trait risk.

Cortisol stress reactivity across psychiatric disorders: A systematic review and meta-analysis.

PubMed

Zorn, Jelle V; Schür, Remmelt R; Boks, Marco P; Kahn, René S; Joëls, Marian; Vinkers, Christiaan H

2017-03-01

The hypothalamus-pituitary-adrenal (HPA) axis and its end product cortisol are essential for an adequate response to stress. Considering the role of stress as a risk factor for psychiatric disorders, it is not surprising that cortisol stress reactivity has frequently been investigated in patients versus healthy individuals. However, the large heterogeneity in measures of the cortisol stress response has hampered a systematic evaluation of the evidence. We here report of a systematic literature review and meta-analysis on cortisol reactivity to psychosocial stress across psychiatric disorders. Original data from authors were obtained to construct standardized cortisol outcomes (the areas under the curve with respect to increase (AUCi) and ground (AUCg)) and to examine the influence of sex and symptomatic state on cortisol stress reactivity. Fourteen studies on major depressive disorder (MDD) (n=1129), 9 on anxiety disorders (n=732, including social anxiety disorder (SAD), posttraumatic stress disorder, panic disorder and mixed samples of anxiety disorders) and 4 on schizophrenia (n=180) were included that used the Trier Social Stress Test or an equivalent psychosocial stress task. Sex-dependent changes in stress reactivity were apparent in MDD and anxiety disorders. Specifically, women with current MDD or an anxiety disorder exhibited a blunted cortisol stress response, whereas men with current MDD or SAD showed an increased cortisol response to psychosocial stress. In individuals with remitted MDD, altered cortisol stress reactivity was less pronounced in women and absent in men. For schizophrenia, cortisol stress reactivity was blunted in both men and women, but the number of studies was limited and showed evidence for publication bias. These findings illustrate that sharing individual data to disentangle the effects of sex, symptom levels and other factors is essential for further understanding of the alterations in cortisol stress reactivity across psychiatric disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.

Early life adversity reduces stress reactivity and enhances impulsive behavior: Implications for health behaviors

PubMed Central

Lovallo, William R.

2012-01-01

Altered reactivity to stress, either in the direction of exaggerated reactivity or diminished reactivity, may signal a dysregulation of systems intended to maintain homeostasis and a state of good health. Evidence has accumulated that diminished reactivity to psychosocial stress may signal poor health outcomes. One source of diminished cortisol and autonomic reactivity is the experience of adverse rearing during childhood and adolescence. The Oklahoma Family Health Patterns Project has examined a cohort of 426 healthy young adults with and without a family history of alcoholism. Regardless of family history, persons who had experienced high degrees of adversity prior to age 16 had a constellation of changes including reduced cortisol and heart rate reactivity, diminished cognitive capacity, and unstable regulation of affect, leading to behavioral impulsivity and antisocial tendencies. We present a model whereby this constellation of physiological, cognitive, and affective tendencies is consistent with altered central dopaminergic activity leading to changes in brain function that may foster impulsive and risky behaviors. These in turn may promote greater use of alcohol other drugs along with adopting poor health behaviors. This model provides a pathway from early life adversity to low stress reactivity that forms a basis for risky behaviors and poor health outcomes. PMID:23085387

Cannabis cue reactivity and craving among never, infrequent and heavy cannabis users.

PubMed

Henry, Erika A; Kaye, Jesse T; Bryan, Angela D; Hutchison, Kent E; Ito, Tiffany A

2014-04-01

Substance cue reactivity is theorized as having a significant role in addiction processes, promoting compulsive patterns of drug-seeking and drug-taking behavior. However, research extending this phenomenon to cannabis has been limited. To that end, the goal of the current work was to examine the relationship between cannabis cue reactivity and craving in a sample of 353 participants varying in self-reported cannabis use. Participants completed a visual oddball task whereby neutral, exercise, and cannabis cue images were presented, and a neutral auditory oddball task while event-related brain potentials (ERPs) were recorded. Consistent with past research, greater cannabis use was associated with greater reactivity to cannabis images, as reflected in the P300 component of the ERP, but not to neutral auditory oddball cues. The latter indicates the specificity of cue reactivity differences as a function of substance-related cues and not generalized cue reactivity. Additionally, cannabis cue reactivity was significantly related to self-reported cannabis craving as well as problems associated with cannabis use. Implications for cannabis use and addiction more generally are discussed.

Cannabis Cue Reactivity and Craving Among Never, Infrequent and Heavy Cannabis Users

PubMed Central

Henry, Erika A; Kaye, Jesse T; Bryan, Angela D; Hutchison, Kent E; Ito, Tiffany A

2014-01-01

Substance cue reactivity is theorized as having a significant role in addiction processes, promoting compulsive patterns of drug-seeking and drug-taking behavior. However, research extending this phenomenon to cannabis has been limited. To that end, the goal of the current work was to examine the relationship between cannabis cue reactivity and craving in a sample of 353 participants varying in self-reported cannabis use. Participants completed a visual oddball task whereby neutral, exercise, and cannabis cue images were presented, and a neutral auditory oddball task while event-related brain potentials (ERPs) were recorded. Consistent with past research, greater cannabis use was associated with greater reactivity to cannabis images, as reflected in the P300 component of the ERP, but not to neutral auditory oddball cues. The latter indicates the specificity of cue reactivity differences as a function of substance-related cues and not generalized cue reactivity. Additionally, cannabis cue reactivity was significantly related to self-reported cannabis craving as well as problems associated with cannabis use. Implications for cannabis use and addiction more generally are discussed. PMID:24264815

Emotion socialization in anxious youth: Parenting buffers emotional reactivity to peer negative events

PubMed Central

Oppenheimer, Caroline W.; Ladouceur, Cecile D.; Waller, Jennifer M.; Ryan, Neal D.; Allen, Kristy Benoit; Sheeber, Lisa; Forbes, Erika E; Dahl, Ronald E.; Silk, Jennifer S.

2016-01-01

Anxious youth exhibit heightened emotional reactivity, particularly to social-evaluative threat, such as peer evaluation and feedback, compared to non-anxious youth. Moreover, normative developmental changes during the transition into adolescence may exacerbate emotional reactivity to peer negative events, particularly for anxious youth. Therefore, it is important to investigate factors that may buffer emotional reactivity within peer contexts among anxious youth. The current study examined the role of parenting behaviors in child emotional reactivity to peer and non-peer negative events among 86 anxious youth in middle childhood to adolescence (Mean age = 11.29, 54% girls). Parenting behavior and affect was observed during a social-evaluative laboratory speech task for youth, and ecological momentary assessment (EMA) methods were used to examine youth emotional reactivity to typical daily negative events within peer and non-peer contexts. Results showed that parent positive behaviors, and low levels of parent anxious affect, during the stressful laboratory task for youth buffered youth negative emotional reactivity to real-world negative peer events, but not non-peer events. Findings inform our understanding of parenting influences on anxious youth's emotional reactivity to developmentally salient negative events during the transition into adolescence. PMID:26783026

Emotion Socialization in Anxious Youth: Parenting Buffers Emotional Reactivity to Peer Negative Events.

PubMed

Oppenheimer, Caroline W; Ladouceur, Cecile D; Waller, Jennifer M; Ryan, Neal D; Allen, Kristy Benoit; Sheeber, Lisa; Forbes, Erika E; Dahl, Ronald E; Silk, Jennifer S

2016-10-01

Anxious youth exhibit heightened emotional reactivity, particularly to social-evaluative threat, such as peer evaluation and feedback, compared to non-anxious youth. Moreover, normative developmental changes during the transition into adolescence may exacerbate emotional reactivity to peer negative events, particularly for anxious youth. Therefore, it is important to investigate factors that may buffer emotional reactivity within peer contexts among anxious youth. The current study examined the role of parenting behaviors in child emotional reactivity to peer and non-peer negative events among 86 anxious youth in middle childhood to adolescence (Mean age = 11.29, 54 % girls). Parenting behavior and affect was observed during a social-evaluative laboratory speech task for youth, and ecological momentary assessment (EMA) methods were used to examine youth emotional reactivity to typical daily negative events within peer and non-peer contexts. Results showed that parent positive behaviors, and low levels of parent anxious affect, during the stressful laboratory task for youth buffered youth negative emotional reactivity to real-world negative peer events, but not non-peer events. Findings inform our understanding of parenting influences on anxious youth's emotional reactivity to developmentally salient negative events during the transition into adolescence.

Landscape review of current HIV 'kick and kill' cure research - some kicking, not enough killing.

PubMed

Thorlund, Kristian; Horwitz, Marc S; Fife, Brian T; Lester, Richard; Cameron, D William

2017-08-29

Current antiretroviral therapy (ART) used to treat human immunodeficiency virus (HIV) patients is life-long because it only suppresses de novo infections. Recent efforts to eliminate HIV have tested the ability of a number of agents to reactivate ('Kick') the well-known latent reservoir. This approach is rooted in the assumption that once these cells are reactivated the host's immune system itself will eliminate ('Kill') the virus. While many agents have been shown to reactivate large quantities of the latent reservoir, the impact on the size of the latent reservoir has been negligible. This suggests that the immune system is not sufficient to eliminate reactivated reservoirs. Thus, there is a need for more emphasis on 'kill' strategies in HIV cure research, and how these might work in combination with current or future kick strategies. We conducted a landscape review of HIV 'cure' clinical trials using 'kick and kill' approaches. We identified and reviewed current available clinical trial results in human participants as well as ongoing and planned clinical trials. We dichotomized trials by whether they did not include or include a 'kill' agent. We extracted potential reasons why the 'kill' is missing from current 'kick and kill' strategies. We subsequently summarized and reviewed current 'kill' strategies have entered the phase of clinical trial testing in human participants and highlighted those with the greatest promise. The identified 'kick' trials only showed promise on surrogate measures activating latent T-cells, but did not show any positive effects on clinical 'cure' measures. Of the 'kill' agents currently being tested in clinical trials, early results have shown small but meaningful proportions of participants remaining off ART for several months with broadly neutralizing antibodies, as well as agents for regulating immune cell responses. A similar result was also recently observed in a trial combining a conventional 'kick' with a vaccine immune booster ('kill'). While an understanding of the efficacy of each individual component is crucial, no single 'kick' or 'kill' agent is likely to be a fully effective cure. Rather, the solution is likely found in a combination of multiple 'kick and kill' interventions.

Size effects in electronic and catalytic properties of unsupported palladium nanoparticles in electrooxidation of formic acid.

PubMed

Zhou, Wei Ping; Lewera, Adam; Larsen, Robert; Masel, Rich I; Bagus, Paul S; Wieckowski, Andrzej

2006-07-13

We report a combined X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and chronoamperometry (CA) study of formic acid electrooxidation on unsupported palladium nanoparticle catalysts in the particle size range from 9 to 40 nm. The CV and CA measurements show that the most active catalyst is made of the smallest (9 and 11 nm) Pd nanoparticles. Besides the high reactivity, XPS data show that such nanoparticles display the highest core-level binding energy (BE) shift and the highest valence band (VB) center downshift with respect to the Fermi level. We believe therefore that we found a correlation between formic acid oxidation current and BE and VB center shifts, which, in turn, can directly be related to the electronic structure of palladium nanoparticles of different particle sizes. Clearly, such a trend using unsupported catalysts has never been reported. According to the density functional theory of heterogeneous catalysis, and mechanistic considerations, the observed shifts are caused by a weakening of the bond strength of the COOH intermediate adsorption on the catalyst surface. This, in turn, results in the increase in the formic acid oxidation rate to CO2 (and in the associated oxidation current). Overall, our measurements demonstrate the particle size effect on the electronic properties of palladium that yields different catalytic activity in the HCOOH oxidation reaction. Our work highlights the significance of the core-level binding energy and center of the d-band shifts in electrocatalysis and underlines the value of the theory that connects the center of the d-band shifts to catalytic reactivity.

Biotribological behavior of Ag-ZrCxN1-x coatings against UHMWPE for joint prostheses devices.

PubMed

Calderon V, S; Sánchez-López, J C; Cavaleiro, A; Carvalho, S

2015-01-01

This study aims to evaluate the structural, mechanical and tribological properties of zirconium carbonitrides (ZrCxN1-x) coatings with embedded silver nanoparticles, produced with the intention of achieving a material with enhanced multi-functional properties, including mechanical strength, corrosion resistance, tribological performance and antibacterial behavior suitable for their use in joint prostheses. The coatings were deposited by direct current (DC) reactive magnetron sputtering onto 316 L stainless steel, changing the silver content from 0 to 20 at% by modifying the current density applied to the targets. Different nitrogen and acetylene gas fluxes were used as reactive gases. The coatings revealed different mixtures of crystalline ZrCxN1-x, silver nanoparticles and amorphous carbon phases. The hardness of the films was found to be mainly controlled by the ratio between the hard (ZrCxN1-x) and soft (Ag and amorphous carbon) phases in the films, fluctuating between 7.4 and 20.4 GPa. The coefficient of friction, measured against ultra-high molecular weight polyethylene (UHMWPE) in Hank's balanced salt solution with 10 gL(-1) albumin, is governed by the surface roughness and hardness. The UHMWPE wear rates were in the same order of magnitude (between 1.4 and 2.0 × 10(-6)mm(3)N(-1)m(-1)), justified by the effect of the protective layer of albumin formed during the tests. The small differences were due to the hydrophobic/hydrophilic character of the surface, as well as to the silver content. Copyright © 2014 Elsevier Ltd. All rights reserved.

Detection of oxidative stress biomarker-induced assembly of gold nanoparticles in retinal pigment epithelial cells

NASA Astrophysics Data System (ADS)

Yasmin, Z.; Lee, Y.; Maswadi, S.; Glickman, R.; Nash, K. L.

2013-02-01

Oxidative stress (OS) is increasingly implicated as an underlying pathogenic mechanism in a wide range of diseases, resulting from an imbalance between the production of reactive oxygen species (ROS) and the system's ability to detoxify the reactive intermediates or repair the resulting damage. ROS can be difficult to detect directly; however, they can be detected indirectly from the effects on oxidative stress biomarkers (OSB), such as glutathione (GSH), 3-nitrotyrosine, homocysteine, and cysteine. Moreover the reaction of transition metals with thiol-containing amino acids (for example GSH) oxidized by ROS can yield reactive products that accumulate with time and contribute to aging and diseases. The study of the interaction between OSB using functionalized nanoparticles (fNPs) has attracted interest because of potential applications in bio-sensors and biomedical diagnostics. A goal of the present work is to use fNPs to detect and ultimately quantitate OS in retinal pigment epithelial (RPE) cells subjected to external stressors, e.g. nonionizing (light) and ionizing (gamma) radiation. Specifically, we are investigating the assembly of gold fNPs mediated by the oxidation of GSH in irradiated RPE cells. The dynamic interparticle interactions had been characterized in previously reported work by monitoring the evolution of the surface plasmon resonance band using spectroscopic analysis (UV-VIS absorption). Here we are comparing the dynamic evolution of fNP assembly using photoacoustic spectroscopy (PAS). We expect that PAS will provide a more sensitive measure allowing these fNP sensors to measure OS in cell-based models without the artifacts limiting the use of current methods, such as fluorescent indicators.

Graft-Derived CCL2 Increases Graft Injury During Antibody-Mediated Rejection of Cardiac Allografts

PubMed Central

Abe, Toyofumi; Su, Charles A.; Iida, Shoichi; Baldwin, William M.; Nonomura, Norio; Takahara, Shiro; Fairchild, Robert L.

2015-01-01

The pathogenic role of macrophages in antibody-mediated rejection (AMR) remains unclear. Monocyte chemoattractant protein-1 (MCP-1/CCL2) is a potent chemotactic factor for monocytes and macrophages. The current studies used a murine model of AMR to investigate the role of graft-derived CCL2 in AMR and how macrophages may participate in antibody-mediated allograft injury. B6.CCR5−/−/CD8−/− recipients rejected MHC-mismatched wild type A/J allografts with high donor-reactive antibody titers and diffuse C4d deposition in the large vessels and myocardial capillaries, features consistent with AMR. In contrast, A/J.CCL2−/− allografts induced low donor-reactive antibody titers and C4d deposition at day 7 post-transplant. Decreased donor-reactive CD4 T cells producing IFN-γ were induced in response to A/J.CCL2−/− vs. wild type allografts. Consequently, A/J.CCL2−/− allograft survival was modestly but significantly longer than A/J allografts. Macrophages purified from wild type allografts expressed high levels of IL-1β and IL-12p40 and this expression and the numbers of classically activated macrophages were markedly reduced in CCL2-deficient allografts on day 7. The results indicate that allograft-derived CCL2 plays an important role in directing classically activated macrophages into allografts during AMR and that macrophages are important contributors to the inflammatory environment mediating graft tissue injury in this pathology, suggesting CCL2 as a therapeutic target for AMR. PMID:25040187

Social Support and Networks: Cardiovascular Responses Following Recall on Immigration Stress Among Chinese Americans

PubMed Central

Suchday, Sonia; Wylie-Rosett, Judith

2014-01-01

Social support has been shown to act as a buffer for cardiovascular responses to stress. However, little is known about how social support and networks are related to cardiovascular responses to immigration stress recall. The current study evaluated the impact of structural and functional support on cardiovascular reaction following immigrant stress recall provocation as well as the moderation effect of interdependent self-construal among first-generation Chinese immigrants. One hundred fifty Chinese immigrants were recruited in the New York Chinatown area. Participants completed questionnaires assessing their levels of social support and networks, and interdependent self-construal. Following adaptation, participants recalled a recent post-immigration stress-provoking situation. Cardiovascular measures were taken during adaptation, stressor task, and recovery period. Hierarchical multiple regression analysis was performed. Social network size and type, as well as perceived emotional support were positively predictive of systolic blood pressure (SBP) reactivity changes. Instrumental support seeking was a positive predictor of SBP and diastolic blood pressure (DBP) reactivity. The moderation effect between instrumental support seeking and interdependent self-construal were significantly predictive of DBP reactivity and recovery, suggesting that perceptions about themselves in relation to others is a crucial factor for determining whether support seeking is beneficial or not. Social support was not a direct buffer on cardiovascular responses to stress among Chinese immigrants. Chinese values of interdependence and collectivism may partly explain the disconfirming results. Still, when interdependent self-construal was taken into account, Chinese immigrants who had less interdependent self-construal, but solicited more instrumental support, had faster adaptation to stress over the long term. PMID:24288021

Antibiotics induce redox-related physiological alterations as part of their lethality

PubMed Central

Dwyer, Daniel J.; Belenky, Peter A.; Yang, Jason H.; MacDonald, I. Cody; Martell, Jeffrey D.; Takahashi, Noriko; Chan, Clement T. Y.; Lobritz, Michael A.; Braff, Dana; Schwarz, Eric G.; Ye, Jonathan D.; Pati, Mekhala; Vercruysse, Maarten; Ralifo, Paul S.; Allison, Kyle R.; Khalil, Ahmad S.; Ting, Alice Y.; Walker, Graham C.; Collins, James J.

2014-01-01

Deeper understanding of antibiotic-induced physiological responses is critical to identifying means for enhancing our current antibiotic arsenal. Bactericidal antibiotics with diverse targets have been hypothesized to kill bacteria, in part by inducing production of damaging reactive species. This notion has been supported by many groups but has been challenged recently. Here we robustly test the hypothesis using biochemical, enzymatic, and biophysical assays along with genetic and phenotypic experiments. We first used a novel intracellular H2O2 sensor, together with a chemically diverse panel of fluorescent dyes sensitive to an array of reactive species to demonstrate that antibiotics broadly induce redox stress. Subsequent gene-expression analyses reveal that complex antibiotic-induced oxidative stress responses are distinct from canonical responses generated by supraphysiological levels of H2O2. We next developed a method to quantify cellular respiration dynamically and found that bactericidal antibiotics elevate oxygen consumption, indicating significant alterations to bacterial redox physiology. We further show that overexpression of catalase or DNA mismatch repair enzyme, MutS, and antioxidant pretreatment limit antibiotic lethality, indicating that reactive oxygen species causatively contribute to antibiotic killing. Critically, the killing efficacy of antibiotics was diminished under strict anaerobic conditions but could be enhanced by exposure to molecular oxygen or by the addition of alternative electron acceptors, indicating that environmental factors play a role in killing cells physiologically primed for death. This work provides direct evidence that, downstream of their target-specific interactions, bactericidal antibiotics induce complex redox alterations that contribute to cellular damage and death, thus supporting an evolving, expanded model of antibiotic lethality. PMID:24803433

Differential reward network functional connectivity in cannabis dependent and non-dependent users☆

PubMed Central

Filbey, Francesca M.; Dunlop, Joseph

2015-01-01

Background Emergent studies show that similar to other substances of abuse, cue-reactivity to cannabis is also associated with neural response in the brain’s reward pathway (Filbey et al., 2009). However, the inter-relatedness of brain regions during cue-reactivity in cannabis users remains unknown. Methods In this study, we conducted a series of investigations to determine functional connectivity during cue-reactivity in 71 cannabis users. First, we used psychophysiological interaction (PPI) analysis to examine coherent neural response to cannabis cues. Second, we evaluated whether these patterns of network functional connectivity differentiated dependent and non-dependent users. Finally, as an exploratory analysis, we determined the directionality of these connections via Granger connectivity analyses. Results PPI analyses showed reward network functional connectivity with the nucleus accumbens (NAc) seed region during cue exposure. Between-group contrasts found differential effects of dependence status. Dependent users (N = 31) had greater functional connectivity with amygdala and anterior cingulate gyrus (ACG) seeds while the non-dependent users (N = 24) had greater functional connectivity with the NAc, orbitofrontal cortex (OFC) and hippocampus seeds. Granger analyses showed that hippocampal and ACG activation preceded neural response in reward areas. Conclusions Both PPI and Granger analyses demonstrated strong functional coherence in reward regions during exposure to cannabis cues in current cannabis users. Functional connectivity (but not regional activation) in the reward network differentiated dependent from non-dependent cannabis users. Our findings suggest that repeated cannabis exposure causes observable changes in functional connectivity in the reward network and should be considered in intervention strategies. PMID:24838032

TRPs as chemosensors (ROS, RNS, RCS, gasotransmitters).

PubMed

Shimizu, Shunichi; Takahashi, Nobuaki; Mori, Yasuo

2014-01-01

The transient receptor potential (trp) gene superfamily encodes TRP proteins that act as multimodal sensor cation channels for a wide variety of stimuli from outside and inside the cell. Upon chemical or physical stimulation of cells, TRP channels transduce electrical and/or Ca(2+) signals via their cation channel activities. These functional features of TRP channels allow the body to react and adapt to different forms of environmental changes. Indeed, members of one class of TRP channels have emerged as sensors of reactive oxygen species (ROS), reactive nitrogen species (RNS), reactive carbonyl species (RCS), and gaseous messenger molecules including molecular oxygen (O2), hydrogen sulfide (H2S), and carbon dioxide (CO2). Hydrogen peroxide (H2O2), an ROS, triggers the production of ADP-ribose, which binds and activates TRPM2. In addition to TRPM2, TRPC5, TRPV1, and TRPA1 are also activated by H2O2 via modification of cysteine (Cys) free sulfhydryl groups. Nitric oxide (NO), a vasoactive gaseous molecule, regulates TRP channels directly via Cys S-nitrosylation or indirectly via cyclic GMP (cGMP)/protein kinase G (PKG)-dependent phosphorylation. Anoxia induced by O2-glucose deprivation and severe hypoxia activates TRPM7 and TRPC6, respectively, whereas TRPA1 serves as a sensor of mild hypoxia and hyperoxia in vagal and sensory neurons. TRPA1 also detects other gaseous molecules, such as hydrogen sulfide (H2S) and carbon dioxide (CO2). In this review, we highlight our current knowledge of TRP channels as chemosensors for ROS, RNS, RCS, and gaseous molecules and discuss their functional impacts on physiological and pathological events.

Parental Management of Peers and Autonomic Nervous System Reactivity in Predicting Adolescent Peer Relationships

PubMed Central

Tu, Kelly M.; Erath, Stephen A.; El-Sheikh, Mona

2016-01-01

The present study examined sympathetic and parasympathetic indices of autonomic nervous system reactivity as moderators of the prospective association between parental management of peers via directing of youths’ friendships and peer adjustment in a sample of typically developing adolescents. Participants included 246 adolescents at Time 1 (T1) [47% boys; 66% European American (EA), 34% African American (AA)] and 226 adolescents at Time 2 (T2; 45% boys; 67% EA, 33% AA). Adolescents were approximately 16 and 17 years old at T1 and T2, respectively. To address study aims, a multi-informant, multi-method longitudinal design was utilized. Skin conductance level (SCL) and respiratory sinus arrhythmia (RSA) were measured during a baseline period and challenge task (star-tracing). Reactivity was computed as a difference score between the task and baseline period. Results from path models revealed that higher levels of mother-reported parental directing predicted decreases in adolescent-reported peer rejection and friends’ deviant behavior from T1 to T2 at relatively low levels of physiological arousal in response to challenge (i.e., low SCL reactivity, RSA augmentation). Further, exploratory analyses indicated that directing was associated with decreases in friends’ deviant behavior and peer rejection particularly among boys who exhibited lower levels of physiological arousal, but increases in friends’ deviant behavior among boys who exhibited higher levels of arousal reflected in RSA withdrawal only. Overall, findings are consistent with prior studies revealing the benefits of parental behavioral control for under-aroused youth, contributing to the growing literature on the interplay of parenting and physiological factors in the adolescent peer domain. PMID:27854467

Direct evidence for tumor necrosis factor-induced mitochondrial reactive oxygen intermediates and their involvement in cytotoxicity.

PubMed Central

Goossens, V; Grooten, J; De Vos, K; Fiers, W

1995-01-01

Tumor necrosis factor (TNF) is selectively cytotoxic to some types of tumor cells in vitro and exerts antitumor activity in vivo. Reactive oxygen intermediates (ROIs) have been implicated in the direct cytotoxic activity of TNF. By using confocal microscopy, flow cytometry, and the ROI-specific probe dihydrorhodamine 123, we directly demonstrate that intracellular ROIs are formed after TNF stimulation. These ROIs are observed exclusively under conditions where cells are sensitive to the cytotoxic activity of TNF, suggesting a direct link between both phenomena. ROI scavengers, such as butylated hydroxyanisole, effectively blocked the formation of free radicals and arrested the cytotoxic response, confirming that the observed ROIs are cytocidal. The mitochondrial glutathione system scavenges the major part of the produced ROIs, an activity that could be blocked by diethyl maleate; under these conditions, TNF-induced ROIs detectable by dihydrorhodamine 123 oxidation were 5- to 20-fold higher. Images Fig. 1 Fig. 4 PMID:7667254

Severity of Acute Infectious Mononucleosis Correlates with Cross-Reactive Influenza CD8 T-Cell Receptor Repertoires

PubMed Central

Aslan, Nuray; Watkin, Levi B.; Gil, Anna; Mishra, Rabinarayan; Clark, Fransenio G.; Welsh, Raymond M.; Ghersi, Dario; Luzuriaga, Katherine

2017-01-01

ABSTRACT Fifty years after the discovery of Epstein-Barr virus (EBV), it remains unclear how primary infection with this virus leads to massive CD8 T-cell expansion and acute infectious mononucleosis (AIM) in young adults. AIM can vary greatly in severity, from a mild transient influenza-like illness to a prolonged severe syndrome. We questioned whether expansion of a unique HLA-A2.01-restricted, cross-reactive CD8 T-cell response between influenza virus A-M158 (IAV-M1) and EBV BMLF1280 (EBV-BM) could modulate the immune response to EBV and play a role in determining the severity of AIM in 32 college students. Only ex vivo total IAV-M1 and IAV-M1+EBV-BM cross-reactive tetramer+ frequencies directly correlated with AIM severity and were predictive of severe disease. Expansion of specific cross-reactive memory IAV-M1 T-cell receptor (TCR) Vβ repertoires correlated with levels of disease severity. There were unique profiles of qualitatively different functional responses in the cross-reactive and EBV-specific CD8 T-cell responses in each of the three groups studied, severe-AIM patients, mild-AIM patients, and seropositive persistently EBV-infected healthy donors, that may result from differences in TCR repertoire use. IAV-M1 tetramer+ cells were functionally cross-reactive in short-term cultures, were associated with the highest disease severity in AIM, and displayed enhanced production of gamma interferon, a cytokine that greatly amplifies immune responses, thus frequently contributing to induction of immunopathology. Altogether, these data link heterologous immunity via CD8 T-cell cross-reactivity to CD8 T-cell repertoire selection, function, and resultant disease severity in a common and important human infection. In particular, it highlights for the first time a direct link between the TCR repertoire with pathogenesis and the diversity of outcomes upon pathogen encounter. PMID:29208744

Impact of Early Cytomegalovirus Reactivation in Cord Blood Stem Cell Recipients in the Current Era

PubMed Central

Ramanathan, Muthalagu; Teira, Pierre; Battiwalla, Minoo; Barrett, John; Ahn, Kwang Woo; Chen, Min; Green, Jamie; Laughlin, Mary; Lazarus, Hillard M.; Marks, David; Saad, Ayman; Seftel, Matthew; Saber, Wael; Savani, Bipin; Waller, Edmund; Wingard, John; Auletta, Jeffery J.; Lindemans, Caroline A.; Boeckh, Michael; Riches, Marcie L.

2016-01-01

Several studies have reported an association between cytomegalovirus (CMV) reactivation and a decreased incidence of relapse for acute myeloid leukemia (AML) after adult donor allogeneic hematopoietic cell transplantation (HCT). Limited data, however, are available on the impact of CMV reactivation on relapse after cord blood stem cell (CB) transplantation. The unique combination of higher incidence of CMV reactivation in the seropositive recipient and lower incidence of graft versus host disease (GvHD) in CB HCT allows for a valuable design to analyze the impact of CMV reactivation. Data from 1684 patients transplanted with cord blood (CB) between 2003 and 2010 for AML and acute lymphoblastic leukemia (ALL) were analyzed. The median time to CMV reactivation was 34 days (range: 2 – 287). CMV reactivation and positive CMV serology were associated with increased non-relapse mortality (NRM) amongst both AML and ALL CB recipients [Reactivation, AML: RR 1.41 (1.07–1.85); ALL: 1.60 (1.14 – 2.23); Serology, AML: RR 1.39 (1.05 – 1.85), ALL: RR 1.61 (1.18 – 2.19)]. For patients with ALL, but not those with AML, this yielded inferior overall survival (p<0.005). Risk of relapse was not impacted by CMV reactivation or positive CMV serostatus for either disease. PMID:27042847

The relationship between carotid blood pressure reactivity to mental stress and carotid intima-media thickness.

PubMed

Spartano, Nicole L; Augustine, Jacqueline A; Lefferts, Wesley K; Gump, Brooks B; Heffernan, Kevin S

2014-10-01

Brachial blood pressure (BP) reactivity to stress predicts large artery damage and future cardiovascular (CV) events. Central BP is an emerging risk factor associated with target organ damage (TOD). Currently, little is known about the central BP response to mental stress and its association to TOD. Twenty-five healthy, non-obese adults completed a computerized mental stress test. Brachial and carotid systolic (S)BP reactivity to stress were calculated as SBP during stress minus resting SBP. Resting carotid intima-media thickness (IMT) was also measured. Carotid SBP reactivity to stress was significantly associated with carotid IMT, independent of age, sex, body mass index, non-high density lipoprotein cholesterol and brachial SBP reactivity to stress (r = 0.386, p < 0.05). The relationship between carotid SBP reactivity and carotid IMT suggests that the central BP response to stress may prove to be an early risk marker for potential subclinical TOD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A meta-analytic review of the association between cortisol reactivity in response to a stressor and attention-deficit hyperactivity disorder.

PubMed

Kamradt, Jaclyn M; Momany, Allison M; Nikolas, Molly A

2018-06-01

A substantial literature suggests that abnormal cortisol reactivity may be a vulnerability for deleterious mental health outcomes, including ADHD. ADHD has been linked with difficulty in emotion regulation and increased risk of experiencing stressors, both of which may be related to psychobiological abnormalities (e.g., abnormal cortisol reactivity). Research has been mixed regarding the association between cortisol reactivity and ADHD. Therefore, the present meta-analytic review (k = 12) sought to quantify this association and review the relevant methodological issues and theoretical implications of this area of research. Overall, no effect was found between cortisol reactivity and ADHD (r = 0), although significant heterogeneity in the analyses suggested that there might be moderators of this association, if one does exist. Results highlight the importance of addressing limitations of the current literature on cortisol reactivity and ADHD and exploring additional indices of emotion regulation that may be associated with ADHD. Implications for future research efforts are discussed.

A meta-analytic review of the association between cortisol reactivity in response to a stressor and attention-deficit hyperactivity disorder

PubMed Central

Momany, Allison M.; Nikolas, Molly A.

2017-01-01

A substantial literature suggests that abnormal cortisol reactivity may be a vulnerability for deleterious mental health outcomes, including ADHD. ADHD has been linked with difficulty in emotion regulation and increased risk of experiencing stressors, both of which may be related to psychobiological abnormalities (e.g., abnormal cortisol reactivity). Research has been mixed regarding the association between cortisol reactivity and ADHD. Therefore, the present meta-analytic review (k = 12) sought to quantify this association and review the relevant methodological issues and theoretical implications of this area of research. Overall, no effect was found between cortisol reactivity and ADHD (r = 0), although significant heterogeneity in the analyses suggested that there might be moderators of this association, if one does exist. Results highlight the importance of addressing limitations of the current literature on cortisol reactivity and ADHD and exploring additional indices of emotion regulation that may be associated with ADHD. Implications for future research efforts are discussed. PMID:28875432

Pore-scale study of multiphase reactive transport in fibrous electrodes of vanadium redox flow batteries

DOE PAGES

Chen, Li; He, YaLing; Tao, Wen -Quan; ...

2017-07-21

The electrode of a vanadium redox flow battery generally is a carbon fibre-based porous medium, in which important physicochemical processes occur. In this work, pore-scale simulations are performed to study complex multiphase flow and reactive transport in the electrode by using the lattice Boltzmann method (LBM). Four hundred fibrous electrodes with different fibre diameters and porosities are reconstructed. Both the permeability and diffusivity of the reconstructed electrodes are predicted and compared with empirical relationships in the literature. Reactive surface area of the electrodes is also evaluated and it is found that existing empirical relationship overestimates the reactive surface under lowermore » porosities. Further, a pore-scale electrochemical reaction model is developed to study the effects of fibre diameter and porosity on electrolyte flow, V II/V III transport, and electrochemical reaction at the electrolyte-fibre surface. Finally, evolution of bubble cluster generated by the side reaction is studied by adopting a LB multiphase flow model. Effects of porosity, fibre diameter, gas saturation and solid surface wettability on average bubble diameter and reduction of reactive surface area due to coverage of bubbles on solid surface are investigated in detail. It is found that gas coverage ratio is always lower than that adopted in the continuum model in the literature. Furthermore, the current pore-scale studies successfully reveal the complex multiphase flow and reactive transport processes in the electrode, and the simulation results can be further upscaled to improve the accuracy of the current continuum-scale models.« less

Global Modelling of the total OH reactivity: validation against measurements and atmospheric implications of the 'missing' sink

NASA Astrophysics Data System (ADS)

Ferracci, Valerio; Archibald, Alexander T.; Pyle, John A.

2017-04-01

The removal of most trace gases emitted into the atmosphere is primarily initiated by reaction with the hydroxyl radical, OH. A number of field campaigns over the last two decades have observed the presence of a "missing" sink of the OH radical in a variety of regions across the planet, from urban areas to remote forests: comparison of the direct measurements of the OH loss rate, also known as total OH reactivity, with the sum of individual known OH sinks (obtained via the simultaneous detection of species such as volatile organic compounds and nitrogen oxides) indicated that, in some cases, up to 80% of the total OH loss rate was unaccounted for. The implications of this finding are significant, as a potentially major OH sink operating in the atmosphere is not currently accounted for in atmospheric models: the presence of an additional OH sink might, for instance, lead to an increase in the atmospheric lifetime of a number of trace species, including high-impact greenhouse gases such as methane. The only modelling of the total OH reactivity is currently performed on a regional scale; a thorough assessment of the impact of the missing sink on the chemistry and climate of the planet by global modelling is therefore highly desirable. In this work a chemistry-climate model (the Met Office's Unified Model with the United Kingdom Chemistry and Aerosols scheme, UM-UKCA) was used to calculate the total OH reactivity at the planetary boundary layer. The model output was validated against available field measurements to verify that the known OH sinks observed in the field were reproduced correctly by the model: a good agreement was found between the data from more than 30 field campaigns and the model output. Following this, the effects of introducing novel OH sinks in the chemistry scheme were investigated. The first step was the introduction in the model of the newly characterised reactions of peroxy radicals (RO2) with OH, the kinetics and products of which have only recently been studied in the laboratory. Results from the UM-UKCA model show that reaction with RO2 might represent a non-negligible OH sink in remote environments, but cannot reconcile field measurements of the total OH reactivity with the sum of the individual sinks. To address this, an unspecified additional sink was added to the model in a series of simulations reproducing different scenarios (e.g., different OH recycling probabilities through the oxidation of the additional sink) with a view to establishing the impact of the additional OH sink on the oxidative capacity of the lower atmosphere.

Physiologic reactivity despite emotional resilience several years after direct exposure to terrorism.

PubMed

Tucker, Phebe M; Pfefferbaum, Betty; North, Carol S; Kent, Adrian; Burgin, Christie E; Parker, Don E; Hossain, Akm; Jeon-Slaughter, Haekyung; Trautman, Richard P

2007-02-01

Six and a half to 7 years after the 1995 terrorist bombing in Oklahoma City, the authors assessed autonomic reactivity to trauma reminders and psychiatric symptoms in adults who had some degree of direct exposure to the blast. Sixty survivors who were listed in a state health department registry of persons exposed to the bombing and 60 age- and gender-matched members of the Oklahoma City metropolitan area community were assessed for symptoms of PTSD and depression and for axis I diagnoses. Heart rate and systolic, diastolic, and mean arterial blood pressures were measured before, during, and after bombing-related interviews. The two groups were compared on both psychometric and physiologic assessments. Posttraumatic stress but not depressive symptoms were significantly more prevalent in the survivor group than in the comparison group, although symptoms were below levels considered clinically relevant. Despite apparent emotional resilience or recovery, blast survivors had significantly greater autonomic reactivity to trauma reminders on all measures than comparison subjects. The results suggest that physiologic assessment may capture long-term effects of terrorism that are not identified by psychometric instruments. The consequences of autonomic reactivity despite emotional resilience years after experiencing trauma are unknown but theoretically could range from facilitating a protective vigilance toward future disasters to more maladaptive avoidance behaviors, somatic symptoms, or medical problems.

Inhibiting Substances as Tracers for the Reactivity Assessment of Fe(0)-PRBs

NASA Astrophysics Data System (ADS)

Dahmke, A.

2001-12-01

Passivation processes of Fe(0)-barriers are well known from lab-studies (Phillips et al., (2000), Schlicker et al., (2000)) and from field-sites. Normally the passivation processes are correlated with the groundwater composition but quantitative prediction and monitoring of the inhibition velocity under field conditions is a serious problem. Currently, only concentration profiles of contaminants, isotope studies or the measurement of reactivity loss with column-experiments of altered Fe(0)-material from the field sites are used for the characterization of Fe(0)-reactivity. All of theses approaches have serious disadvantages and limitations. Thus the sampling of unaltered Fe(0)-material out of the reactive barrier is difficult and the perturbed installation of the material in column experiments may lead to significant modification in the field behaviour of the Fe(0)-barrier. In addition, the concentration profile of the contaminant is not always a good tool for reactivity estimations due to uncertainties in hydrogeological boundary conditions. The same general restrictions apply also for isotope studies, in which the shift of the d13C signal is used as an indicator for degradation processes of the chlorinated aliphatics. Therefore here the use of Fe(0) inhibiting substances as reactive tracers is presented as a new approach for the characterization of the Fe(0)-reactivity. The methodology of reactive tracers to determine reactive surface areas of Fe(III) in porous was developed last year by Veehmayer et al. (2000) by interpretation of the breakthrough curves of species with known specific interactions with the solid phase. The concept is also applicable for the estimation of reactive sites in Fe(0)-columns, so that the breakthrough curves of oxidants like NO3-, CrO42- or oxidizing organic substances may be interpreted as indicative of reactive reducing sites in the Fe(0)-column. Such correlation was already shown by Schlicker et al., (2000), who explained the movement of passivation fronts by the blocking of reactive sites at the Fe(0) surface. To investigate this approach different column experiments with passivated Fe(0) are being currently carried out. Initial results from the lab indicate that different inorganic as well as organic substances can be used for characterization of the passivation state of the Fe(0) surface. Application of reactive tracer combinations also give some clues about the surface properties of the inhibiting substances, which might be helpful with respect to reactivation approaches for passivated permeable Fe(0)-barriers. Despite the first encouraging but more phenomenological lab results some theoretical problems, like the alteration of the specific surface area during the lab experiments or competition processes between organic or inorganic compounds at the altered surface of the Fe particles have to be addressed more in detail.

Planned and reactive agility performance in semiprofessional and amateur basketball players.

PubMed

Lockie, Robert G; Jeffriess, Matthew D; McGann, Tye S; Callaghan, Samuel J; Schultz, Adrian B

2014-09-01

Research indicates that planned and reactive agility are different athletic skills. These skills have not been adequately assessed in male basketball players. To define whether 10-m-sprint performance and planned and reactive agility measured by the Y-shaped agility test can discriminate between semiprofessional and amateur basketball players. Ten semiprofessional and 10 amateur basketball players completed 10-m sprints and planned- and reactive-agility tests. The Y-shaped agility test involved subjects sprinting 5 m through a trigger timing gate, followed by a 45° cut and 5-m sprint to the left or right through a target gate. In the planned condition, subjects knew the cut direction. For reactive trials, subjects visually scanned to find the illuminated gate. A 1-way analysis of variance (P < .05) determined between-groups differences. Data were pooled (N = 20) for a correlation analysis (P < .05). The reactive tests differentiated between the groups; semiprofessional players were 6% faster for the reactive left (P = .036) and right (P = .029) cuts. The strongest correlations were between the 10-m sprints and planned-agility tests (r = .590-.860). The reactive left cut did not correlate with the planned tests. The reactive right cut moderately correlated with the 10-m sprint and planned right cut (r = .487-.485). The results reemphasized that planned and reactive agility are separate physical qualities. Reactive agility discriminated between the semiprofessional and amateur basketball players; planned agility did not. To distinguish between male basketball players of different ability levels, agility tests should include a perceptual and decision-making component.

Extensive CD4 and CD8 T-cell cross-reactivity between alphaherpesviruses1

PubMed Central

Dong, Lichun; Russell, Ronnie M.; Barlow, Russell S.; Haas, Juergen G.; Ramchandani, Meena S.; Johnston, Christine; Buus, Soren; Redwood, Alec J.; White, Katie D.; Mallal, Simon A.; Phillips, Elizabeth J.; Posavad, Christine M.; Wald, Anna; Koelle, David M.

2015-01-01

The alphaherpesvirinae subfamily includes HSV types 1 and 2 and the sequence-divergent pathogen varicella zoster virus (VZV). T cells, controlled by TCR and HLA molecules that tolerate limited epitope amino acid variation, might cross-react between these microbes. We show that memory PBMC expansion with either HSV or VZV enriches for CD4 T cell lines that recognize the other agent at the whole virus, protein, and peptide levels, consistent with bi-directional cross-reactivity. HSV-specific CD4 T cells recovered from HSV seronegative persons can be partially explained by such VZV cross-reactivity. HSV-1-reactive CD8 T cells also cross-react with VZV-infected cells, full-length VZV proteins, and VZV peptides, and kill VZV-infected dermal fibroblasts. Mono- and cross-reactive CD8 T cells use distinct TCRB CDR3 sequences. Cross-reactivity to VZV is reconstituted by cloning and expressing TCRA/TCRB receptors from T-cells that are initially isolated using HSV reagents. Overall, we define 13 novel CD4 and CD8 HSV-VZV cross-reactive epitopes and strongly imply additional cross-reactive peptide sets. Viral proteins can harbor both CD4 and CD8 HSV/VZV cross-reactive epitopes. Quantitative estimates of HSV/VZV cross-reactivity for both CD4 and CD8 T cells vary from 10-50%. Based on these findings, we hypothesize host herpesvirus immune history may influence the pathogenesis and clinical outcome of subsequent infections or vaccinations for related pathogens, and that cross-reactive epitopes and TCRs may be useful for multi-alphaherpesvirus vaccine design and adoptive cellular therapy. PMID:26810224

Detection of gain enhancement in laser-induced fluorescence of rhodamine B lasing dye by silicon dioxide nanostructures-coated cavity

NASA Astrophysics Data System (ADS)

Al-Tameemi, Mohammed N. A.

2018-03-01

In this work, nanostructured silicon dioxide films are deposited by closed-field unbalanced direct-current (DC) reactive magnetron sputtering technique on two sides of quartz cells containing rhodamine B dye dissolved in ethanol with 10‒5 M concentration as a random gain medium. The preparation conditions are optimized to prepare highly pure SiO2 nanostructures with a minimum particle size of about 20 nm. The effect of SiO2 films as external cavity for the random gain medium is determined by the laser-induced fluorescence of this medium, and an increase of about 200% in intensity is observed after the deposition of nanostructured SiO2 thin films on two sides of the dye cell.

Expansion of high-temperature; high-pressure data set for coal gasification. Fifth quarterly report, September 28-December 28, 1985

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

Solomon, P.R.; Serio, M.A.; Hamblen, D.G.

1985-01-01

During the fifth quarter, the gas mixing station for the high pressure reactor (HPR) system was completed. This station allows us to make reproducible binary mixtures of any two gases. It will be used for pyrolysis experiments in helium/nitrogen or oxygen/nitrogen and gasification experiments in helium/nitrogen or oxygen/nitrogen and gasification experiments in carbon dioxide/nitrogen. In addition, work began on modifications of the HPR system for high pressure (600 psig) operation. A limited amount of data was taken with the HPR system due to the modifications for the mixing station. However, the test plan experiments for pyrolysis in mixtures of heliummore » and nitrogen were completed. In general, there is a slightly higher yield of volatiles and lower yield of char as the helium content (heating rate) increases. A new technique for measuring char reactivity resulted from an Army SBIR program and was further developed under our other METC Contract. It has also been used to characterize chars generated under the current program. It was evident that the severity of the thermal treatment had a direct effect on char reactivity. In this regard, rapid heating to a relatively low temperature was most favorable while slow heating to a high temperature was least favorable. With regard to pressure effects on reactivity, our preliminary data indicated that higher pressures produce chars lower initial reactivity. A total of four experiments were done in the heated tube reactor (HTR) at 60 psig, 800/sup 0/C maximum tube temperature. The trends are the same as observed in the atmospheric pressure experiments for the same tube temperature and cold gas velocity. During the past quarter, a particle temperature (PT) model was under development for the high pressure entrained flow reactor (HPR). 5 refs., 5 figs.« less

Immune activation after immunization of the neonatal calves with a commercial heat-killed vaccine

USDA-ARS?s Scientific Manuscript database

A major drawback of current whole-cell vaccines for Mycobacterium avium subsp. paratuberculosis is the interference with diagnostic tests for bovine tuberculosis and paratuberculosis. The current study was designed to explore cross-reactivity of the current USDA commercial vaccine for MAP with diagn...

Child Maltreatment and Autonomic Nervous System Reactivity: Identifying Dysregulated Stress Reactivity Patterns using the Biopsychosocial Model of Challenge and Threat

PubMed Central

McLaughlin, Katie A.; Sheridan, Margaret A.; Alves, Sonia; Mendes, Wendy Berry

2014-01-01

OBJECTIVE Disruptions in stress response system development have been posited as mechanisms linking child maltreatment (CM) to psychopathology. Existing theories predict elevated sympathetic nervous system (SNS) reactivity following CM, but evidence for this is inconsistent. We present a novel framework for conceptualizing stress reactivity following CM using the biopsychosocial model of challenge and threat. We predicted that in the context of a social-evaluative stressor, maltreated adolescents would exhibit a threat pattern of reactivity, involving SNS activation paired with elevated vascular resistance and blunted cardiac output (CO) reactivity. METHODS A sample of 168 adolescents (mean age=14.9 years) participated. Recruitment targeted maltreated adolescents; 38.2% qualified as maltreated. Electrocardiogram, impedance cardiography, and blood pressure were acquired at rest and during an evaluated social stressor (Trier Social Stress Test). Pre-ejection period (PEP), CO, and total peripheral resistance (TPR) reactivity were computed during task preparation, speech-delivery, and verbal mental-arithmetic. Internalizing and externalizing symptoms were assessed. RESULTS Maltreatment was unrelated to PEP reactivity during preparation or speech, but maltreated adolescents had reduced PEP reactivity during math. Maltreatment exposure (F(1,145)=3.8-9.4, p=.053-<.001) and severity (β=−.10-.12, p=.030-.007) were associated with significantly reduced CO reactivity during all components of the stress-task and marginally associated with elevated TPR reactivity (F(1,145)=3.8-9.4, p=.053-<.001; β=.07-.11, p=.11-.009, respectively). Threat reactivity was negatively associated with externalizing symptoms. CONCLUSIONS Child maltreatment is associated with a dysregulated pattern of physiological reactivity consistent with theoretical conceptualizations of threat but not previously examined in relation to maltreatment, suggesting a more nuanced pattern of stress reactivity than predicted by current theoretical models. PMID:25170753

Fractional Factorial Design Study on the Performance of GAC-Enhanced Electrocoagulation Process Involved in Color Removal from Dye Solutions.

PubMed

Secula, Marius Sebastian; Cretescu, Igor; Cagnon, Benoit; Manea, Liliana Rozemarie; Stan, Corneliu Sergiu; Breaban, Iuliana Gabriela

2013-07-10

The aim of this study was to determine the effects of main factors and interactions on the color removal performance from dye solutions using the electrocoagulation process enhanced by adsorption on Granular Activated Carbon (GAC). In this study, a mathematical approach was conducted using a two-level fractional factorial design ( FFD ) for a given dye solution. Three textile dyes: Acid Blue 74, Basic Red 1, and Reactive Black 5 were used. Experimental factors used and their respective levels were: current density (2.73 or 27.32 A/m²), initial pH of aqueous dye solution (3 or 9), electrocoagulation time (20 or 180 min), GAC dose (0.1 or 0.5 g/L), support electrolyte (2 or 50 mM), initial dye concentration (0.05 or 0.25 g/L) and current type (Direct Current- DC or Alternative Pulsed Current- APC ). GAC-enhanced electrocoagulation performance was analyzed statistically in terms of removal efficiency, electrical energy, and electrode material consumptions, using modeling polynomial equations. The statistical significance of GAC dose level on the performance of GAC enhanced electrocoagulation and the experimental conditions that favor the process operation of electrocoagulation in APC regime were determined. The local optimal experimental conditions were established using a multi-objective desirability function method.

Profiles of disruptive behavior across early childhood: Contributions of frustration reactivity, physiological regulation, and maternal behavior

PubMed Central

Degnan, Kathryn A.; Calkins, Susan D.; Keane, Susan P.; Hill-Soderlund, Ashley L.

2010-01-01

Disruptive behavior, including aggression, defiance, and temper tantrums, typically peaks in early toddlerhood and decreases by school entry; however, some children do not show this normative decline. The current study examined disruptive behavior in 318 boys and girls at 2, 4, and 5 years of age and frustration reactivity, physiological regulation, and maternal behavior in the laboratory at 2 years of age. A latent profile analysis (LPA) resulted in 4 longitudinal profiles of disruptive behavior, which were differentiated by interactions between reactivity, regulation, and maternal behavior. A high profile was associated with high reactivity combined with high maternal control or low regulation combined with low maternal control. Results are discussed from a developmental psychopathology perspective. PMID:18826530

Regioisomer-Specific Mechanochromism of Naphthopyran in Polymeric Materials.

PubMed

Robb, Maxwell J; Kim, Tae Ann; Halmes, Abigail J; White, Scott R; Sottos, Nancy R; Moore, Jeffrey S

2016-09-28

Transformation of naphthopyran into a colored merocyanine species in polymeric materials is achieved using mechanical force. We demonstrate that the mechanochemical reactivity of naphthopyran is critically dependent on the regiochemistry, with only one particular substitution pattern leading to successful mechanochemical activation. Two alternative regioisomers with different polymer attachment points are demonstrated to be mechanochemically inactive. This trend in reactivity is accurately predicted by DFT calculations, reinforcing predictive capabilities in mechanochemical systems. We rationalize the reactivity differences between naphthopyran regioisomers in terms of the alignment of the target C-O pyran bond with the direction of the applied mechanical force and its effect on mechanochemical transduction along the reaction coordinate.

Diazo Compounds as Highly Tunable Reactants in 1,3-Dipolar Cycloaddition Reactions with Cycloalkynes†

PubMed Central

McGrath, Nicholas A.

2012-01-01

Diazo compounds, which can be accessed directly from azides by deimidogenation, are shown to be extremely versatile dipoles in 1,3-dipolar cycloaddition reactions with a cyclooctyne. The reactivity of a diazo compound can be much greater or much less than its azide analog, and is enhanced markedly in polar-protic solvents. These reactivities are predictable from frontier molecular orbital energies. The most reactive diazo compound exhibited the highest known second-order rate constant to date for a dipolar cycloaddition with a cycloalkyne. These data provide a new modality for effecting chemoselective reactions in a biological context. PMID:23227302

Utility of reactively sputtered CuN{sub x} films in spintronics devices

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

Fang Yeyu; Persson, J.; NanOsc AB, Electrum 205, 164 40 Kista

2012-04-01

We have studied nitrified copper (CuN{sub x}) thin films grown by reactive sputtering in the context of spintronic devices. The Ar-to-N{sub 2} flow ratio enables tunability of the electrical resistivity and surface roughness of the CuN{sub x} films, with the former increasing to nearly 20 times that of Cu, and the latter reduced to the atomic scale. Incorporating this into a Ta/CuN{sub x}/Ta seed stack for spin valves improves the current-in-plane (CIP) magnetoresistance; maximum magnetoresistance results with CuN{sub x} seed layer and Cu interlayer. Finally, finite element modeling results are presented that suggest the use of CuN{sub x} in nanocontactmore » spin torque oscillators can enhance current densities by limiting the current spread through the device. This may positively impact threshold currents, power requirements, and device reliability.« less

Disarming the gunslinger effect: Reaction beats intention for cooperative actions.

PubMed

Weller, Lisa; Kunde, Wilfried; Pfister, Roland

2018-04-01

According to the famous physicist Niels Bohr, gunfights at high noon in Western movies not only captivate the cinema audience but also provide an accurate illustration of a psychophysical law. He suggested that willed actions come with slower movement execution than reactions, and therefore that a film's hero is able to get the upper hand even though the villain normally draws first. A corresponding "gunslinger effect" has been substantiated by empirical studies. Because these studies used a markedly competitive setting, however, it is currently unclear whether the gunslinger effect indeed reflects structural differences between willed actions and reactive movements, or whether it is a by-product of the competitive setting. To obtain bullet-proof evidence for a true reactive advantage, we investigated willed and reactive movements during a cooperative interaction of two participants. A pronounced reactive advantage emerged, indicating that two independent systems indeed control willed and reactive movements.

Modes of adaptation of peripheral neuroendocrine mechanisms of the sympatho-adrenal system to short-term stress as studied in two inbred rat strains.

PubMed

Gilad, G M; Jimerson, D C

1981-02-09

Alterations in mechanisms involved in catecholamine (CA) and corticosterone (B) regulation following short periods of stress have been investigated in two inbred rat strains: a strain more reactive to stress, Wistar-Kyoto (WK), and a less reactive strain, Brown-Norway (BN). Measurements after decapitation stress alone and after decapitation following different periods of immobilization stress, indicate that: (a) plasma CA levels immediately after severe stress (i.e. decapitation) are directly related to the behavioral reactivity of the two rat strains to stress but inversely related to adrenal gland size, their content of CA and biosynthetic enzymes, and to plasma levels of MHPG; (b) levels of B in adrenal glands and in plasma after stress are similar in both strains, in spite of different gland sizes; (c) CAT activity in presynaptic sympathetic terminals is directly related to plasma CA after short-term stress; and (d) liver COMT activity is directly related to plasma CA levels after stress, but inversely plasma levels of MHPG. The implications of the findings are discussed further in the text and lead to the conclusion that the BN strain represents a mode of a slower response to stressful stimuli than WK.

Comparing reactive and memory-one strategies of direct reciprocity

NASA Astrophysics Data System (ADS)

Baek, Seung Ki; Jeong, Hyeong-Chai; Hilbe, Christian; Nowak, Martin A.

2016-05-01

Direct reciprocity is a mechanism for the evolution of cooperation based on repeated interactions. When individuals meet repeatedly, they can use conditional strategies to enforce cooperative outcomes that would not be feasible in one-shot social dilemmas. Direct reciprocity requires that individuals keep track of their past interactions and find the right response. However, there are natural bounds on strategic complexity: Humans find it difficult to remember past interactions accurately, especially over long timespans. Given these limitations, it is natural to ask how complex strategies need to be for cooperation to evolve. Here, we study stochastic evolutionary game dynamics in finite populations to systematically compare the evolutionary performance of reactive strategies, which only respond to the co-player’s previous move, and memory-one strategies, which take into account the own and the co-player’s previous move. In both cases, we compare deterministic strategy and stochastic strategy spaces. For reactive strategies and small costs, we find that stochasticity benefits cooperation, because it allows for generous-tit-for-tat. For memory one strategies and small costs, we find that stochasticity does not increase the propensity for cooperation, because the deterministic rule of win-stay, lose-shift works best. For memory one strategies and large costs, however, stochasticity can augment cooperation.

Comparing reactive and memory-one strategies of direct reciprocity

PubMed Central

Baek, Seung Ki; Jeong, Hyeong-Chai; Hilbe, Christian; Nowak, Martin A.

2016-01-01

Direct reciprocity is a mechanism for the evolution of cooperation based on repeated interactions. When individuals meet repeatedly, they can use conditional strategies to enforce cooperative outcomes that would not be feasible in one-shot social dilemmas. Direct reciprocity requires that individuals keep track of their past interactions and find the right response. However, there are natural bounds on strategic complexity: Humans find it difficult to remember past interactions accurately, especially over long timespans. Given these limitations, it is natural to ask how complex strategies need to be for cooperation to evolve. Here, we study stochastic evolutionary game dynamics in finite populations to systematically compare the evolutionary performance of reactive strategies, which only respond to the co-player’s previous move, and memory-one strategies, which take into account the own and the co-player’s previous move. In both cases, we compare deterministic strategy and stochastic strategy spaces. For reactive strategies and small costs, we find that stochasticity benefits cooperation, because it allows for generous-tit-for-tat. For memory one strategies and small costs, we find that stochasticity does not increase the propensity for cooperation, because the deterministic rule of win-stay, lose-shift works best. For memory one strategies and large costs, however, stochasticity can augment cooperation. PMID:27161141

Social Problems as a Mediator of the Link between Reactive Aggression and Withdrawn/Depressed Symptoms

ERIC Educational Resources Information Center

Fite, Paula J.; Rathert, Jamie L.; Stoppelbein, Laura; Greening, Leilani

2012-01-01

The current study examined whether social problems accounted for the relation between reactive aggression and withdrawn/depressed symptoms in a sample of 147 children (54.4% male) ranging from 5 to 13 years of age (M = 8.22 years) who attended a community based after-school program. Findings suggested that indeed social problems mediated the link…

Does Reactivating a Witnessed Memory Increase Its Susceptibility to Impairment by Subsequent Misinformation?

ERIC Educational Resources Information Center

Rindal, Eric J.; DeFranco, Rachel M.; Rich, Patrick R.; Zaragoza, Maria S.

2016-01-01

In a recent PNAS article, Chan and LaPaglia (2013) provided arguments and evidence to support the claim that reactivating a witnessed memory (by taking a test) renders the memory labile and susceptible to impairment by subsequent misinformation. In the current article, we argue that Chan and LaPaglia's (2013) findings are open to alternative…

Electrophysiological Responses to Auditory Novelty in Temperamentally Different 9-Month-Old Infants

ERIC Educational Resources Information Center

Marshall, Peter J.; Reeb, Bethany C.; Fox, Nathan A.

2009-01-01

Behavioral reactivity to novel stimuli in the first half-year of life has been identified as a key aspect of early temperament and a significant precursor of approach and withdrawal tendencies to novelty in later infancy and early childhood. The current study examines the neural signatures of reactivity to novel auditory stimuli in 9-month-old…

Stress reactivity and personality in extreme sport athletes: The psychobiology of BASE jumpers.

PubMed

Monasterio, Erik; Mei-Dan, Omer; Hackney, Anthony C; Lane, Amy R; Zwir, Igor; Rozsa, Sandor; Cloninger, C Robert

2016-12-01

This is the first report of the psychobiology of stress in BASE jumpers, one of the most dangerous forms of extreme sport. We tested the hypotheses that indicators of emotional style (temperament) predict salivary cortisol reactivity, whereas indicators of intentional goal-setting (persistence and character) predict salivary alpha-amylase reactivity during BASE jumping. Ninety-eight subjects completed the Temperament and Character Inventory (TCI) the day before the jump, and 77 also gave salivary samples at baseline, pre-jump on the bridge over the New River Gorge, and post-jump upon landing. Overall BASE jumpers are highly resilient individuals who are highly self-directed, persistent, and risk-taking, but they are heterogeneous in their motives and stress reactivity in the Hypothalamic-Pituitary-Adrenal (HPA) stress system (cortisol reactivity) and the sympathetic arousal system (alpha-amylase reactivity). Three classes of jumpers were identified using latent class analysis based on their personality profiles, prior jumping experience, and levels of cortisol and alpha-amylase at all three time points. "Masterful" jumpers (class 1) had a strong sense of self-directedness and mastery, extensive prior experience, and had little alpha-amylase reactivity and average cortisol reactivity. "Trustful" jumpers (class 2) were highly cooperative and trustful individuals who had little cortisol reactivity coincident with the social support they experienced prior to jumping. "Courageous" jumpers (class 3) were determined despite anxiety and inexperience, and they had high sympathetic reactivity but average cortisol activation. We conclude that trusting social attachment (Reward Dependence) and not jumping experience predicted low cortisol reactivity, whereas persistence (determination) and not jumping experience predicted high alpha-amylase reactivity. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Anomalous effects in the aluminum oxide sputtering yield

NASA Astrophysics Data System (ADS)

Schelfhout, R.; Strijckmans, K.; Depla, D.

2018-04-01

The sputtering yield of aluminum oxide during reactive magnetron sputtering has been quantified by a new and fast method. The method is based on the meticulous determination of the reactive gas consumption during reactive DC magnetron sputtering and has been deployed to determine the sputtering yield of aluminum oxide. The accuracy of the proposed method is demonstrated by comparing its results to the common weight loss method excluding secondary effects such as redeposition. Both methods exhibit a decrease in sputtering yield with increasing discharge current. This feature of the aluminum oxide sputtering yield is described for the first time. It resembles the discrepancy between published high sputtering yield values determined by low current ion beams and the low deposition rate in the poisoned mode during reactive magnetron sputtering. Moreover, the usefulness of the new method arises from its time-resolved capabilities. The evolution of the alumina sputtering yield can now be measured up to a resolution of seconds. This reveals the complex dynamical behavior of the sputtering yield. A plausible explanation of the observed anomalies seems to originate from the balance between retention and out-diffusion of implanted gas atoms, while other possible causes are commented.

Unobtrusive measures in behavioral assessment

PubMed Central

Kazdin, Alan E.

1979-01-01

A major distinguishing characteristic of behavioral assessment is the direct assessment of overt behavior. Direct assessment is assumed to provide a sample of behavior that reflects client performance in the situation in which behavior is assessed, even if the assessment procedures were not implemented. Yet, in the majority of investigations, behavioral assessment procedures are obtrusive, i.e., subjects are aware that their behavior is being assessed. The potential problem with obtrusive assessment is that it may be reactive, i.e., affect how subjects perform. Recent research has demonstrated that obtrusive observations often are reactive and that behaviors assessed under obtrusive and unobtrusive conditions bear little relation. From methodological and applied perspectives, additional attention needs to be given to unobtrusive measures of behavior change. The present paper illustrates unobtrusive measures in behavior modification including direct observations, archival records, and physical traces of performance. In addition, validation and assessment problems, questions about the obtrusiveness of the measures, and ethical issues are discussed. PMID:16795622

Attributional bias and reactive aggression.

PubMed

Hudley, C; Friday, J

1996-01-01

This article looks at a cognitive behavioral intervention designed to reduce minority youths' (Latino and African-American boys) levels of reactive peer-directed aggression. The BrainPower Program trains aggressive boys to recognize accidental causation in ambiguous interactions with peers. The objective of this research is to evaluate the effectiveness of this attribution retraining program in reducing levels of reactive, peer-directed aggression. This research hypothesizes that aggressive young boys' tendency to attribute hostile intentions to others in ambiguous social interactions causes display of inappropriate, peer-directed aggression. A reduction in attributional bias should produce a decrease in reactive physical and verbal aggression directed toward peers. A 12-session, attributional intervention has been designed to reduce aggressive students' tendency to infer hostile intentions in peers following ambiguous peer provocations. The program trains boys to (1) accurately perceive and categorize the available social cues in interactions with peers, (2) attribute negative outcomes of ambiguous causality to accidental or uncontrollable causes, and (3) generate behaviors appropriate to these retrained attributions. African-American and Latino male elementary-school students (N = 384), in grades four-six, served as subjects in one of three groups: experimental attribution retraining program, attention training, and no-attention control group. Three broad categories of outcome data were collected: teacher and administrator reports of behavior, independent observations of behavior, and self-reports from participating students. Process measures to assess implementation fidelity include videotaped training sessions, observations of intervention sessions, student attendance records, and weekly team meetings. The baseline data indicated that students who were evenly distributed across the four sites were not significantly different on the baseline indicators: student cognitions, teacher perceptions of behavior, and student suspension rates. Substantial evidence has shown that aggressive boys tend to attribute hostile intentions to peers, often resulting in inappropriate retaliatory aggression. The BrainPower Program was designed to determine whether psychoeducational strategies in a school context are effective in reducing attributional bias and whether such reductions significantly reduce aggressive behavior.

Elevated Concentrations of Serum Immunoglobulin Free Light Chains in Systemic Lupus Erythematosus Patients in Relation to Disease Activity, Inflammatory Status, B Cell Activity and Epstein-Barr Virus Antibodies

PubMed Central

Draborg, Anette H.; Lydolph, Magnus C.; Westergaard, Marie; Olesen Larsen, Severin; Nielsen, Christoffer T.; Duus, Karen; Jacobsen, Søren; Houen, Gunnar

2015-01-01

Objective In this study, we examined the concentration of serum immunoglobulin free light chains (FLCs) in systemic lupus erythematosus (SLE) patients and investigated its association with various disease parameters in order to evaluate the role of FLCs as a potential biomarker in SLE. Furthermore, FLCs’ association with Epstein-Barr virus (EBV) antibodies was examined. Methods Using a nephelometric assay, κFLC and λFLC concentrations were quantified in sera from 45 SLE patients and 40 healthy controls. SLE patients with renal insufficiency were excluded in order to preclude high concentrations of serum FLCs due to decreased clearance. Results Serum FLC concentrations were significantly elevated in SLE patients compared to healthy controls (p<0.0001) also after adjusting for Ig levels (p<0.0001). The concentration of serum FLCs correlated with a global disease activity (SLE disease activity index (SLEDAI)) score of the SLE patients (r = 0.399, p = 0.007). Furthermore, concentrations of FLCs correlated with titers of dsDNA antibodies (r = 0.383, p = 0.009), and FLC levels and SLEDAI scores correlated in the anti-dsDNA-positive SLE patients, but not in anti-dsDNA-negative SLE patients. Total immunoglobulin (IgG and IgA) concentrations correlated with FLC concentrations and elevated FLC levels were additionally shown to associate with the inflammatory marker C-reactive protein and also with complement consumption determined by low C4 in SLE patients. Collectively, results indicated that elevated serum FLCs reflects increased B cell activity in relation to inflammation. SLE patients had an increased seropositivity of EBV-directed antibodies that did not associate with elevated FLC concentrations. An explanation for this could be that serum FLC concentrations reflect the current EBV activity (reactivation) whereas EBV-directed antibodies reflect the extent of previous infection/reactivations. Conclusion SLE patients have elevated concentrations of serum FLCs that correlate with global disease activity scores and especially serologic markers for active disease. These findings are suggestive of circulating FLCs having potential as a new supplementary serologic biomarker in SLE. PMID:26402865

Popularity differentially predicts reactive and proactive aggression in early adolescence.

PubMed

Stoltz, Sabine; Cillessen, Antonius H N; van den Berg, Yvonne H M; Gommans, Rob

2016-01-01

Previous research has indicated that peer popularity is associated with aggressive behavior. However, it is not yet clear whether popularity is uniquely related to different functions of aggression. In this study, we examined associations between peer-perceived popularity, and reactive and proactive aggression using a cross-sectional and a longitudinal design. Yearly sociometric measures of popularity, and reactive and proactive aggression were gathered from 266 seventh and eight grade adolescents (Mage grade 7 = 12.80, SDage  = .40). Popularity was positively correlated with proactive aggression and negatively correlated with reactive aggression, both concurrently as over time. Curvilinear trends indicated that a significant minority of low versus high popular adolescents showed both functions of aggression. Somewhat stronger effects of popularity on proactive aggression were found for boys than girls. Stably popular adolescents showed the highest levels of proactive aggression, whereas stably unpopular youth showed the highest levels of reactive aggression. Implications and directions for future research are discussed. © 2015 Wiley Periodicals, Inc.

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

Smed, T.; Andersson, G.

In this paper, damping of slow oscillations with active and reactive power modulation of HVDC-links is analyzed with the aim of gaining a physical insight into the problem. The analysis shows that active power modulation is efficient when applied to a short mass-scaled electrical distance from one of the swinging machines, and reactive power modulation is most efficient when there exists a well-defined power flow direction and the modulation is made at a point close to the electrical midpoint between the swinging machines. It is shown that the intuitively appealing feedback signals frequency and derivative of the voltage are appropriatemore » for active and reactive power modulation, respectively. The impact of the constraints imposed by the HVDC equations are analyzed, and it is determined when the implicit reactive power modulation resulting from constant [gamma] control may be detrimental for the damping.« less

Ozonation of the pharmaceutical compound ranitidine: reactivity and kinetic aspects.

PubMed

Rivas, Javier; Gimeno, Olga; Encinas, Angel; Beltrán, Fernando

2009-07-01

Ranitidine has been ozonated under different operating conditions of pH, applied ozone dose, initial ranitidine concentration and presence or absence of free radical inhibitors. Results of ranitidine evolution with time indicate a high reactivity of this compound with molecular ozone. Mineralization levels achieved in the order of 20-25% suggest that the (CH3)2-N-CH2- moiety bonded to the furan ring could be separated from the rest of the ranitidine structure and further mineralized. Only alkaline conditions (pH=11) are capable of increasing TOC conversion up to values close to 70%. Determination of the direct ozonation rate constant for ranitidine by means of competitive kinetics reveals an unacceptable dependence of the aforementioned constant with the reference compound reactivity. It is hypothesised that only reference compounds with reactivity similar to the target species should be used.

Grass-specific CD4(+) T-cells exhibit varying degrees of cross-reactivity, implications for allergen-specific immunotherapy.

PubMed

Archila, L D; DeLong, J H; Wambre, E; James, E A; Robinson, D M; Kwok, W W

2014-07-01

Conceptually, allergic responses may involve cross-reactivity by antibodies or T-cells. While IgE cross-reactivity among grass-pollen allergens has been observed, cross-reactivity at the allergen-specific T-cell level has been less documented. Identification of the patterns of cross-reactivity may improve our understanding, allowing optimization of better immunotherapy strategies. We use Phleum pratense as model for the studying of cross-reactivity at the allergen-specific CD4(+) T cell level among DR04:01 restricted Pooideae grass-pollen T-cell epitopes. After in vitro culture of blood mono-nucleated cells from grass-pollen-allergic subjects with specific Pooideae antigenic epitopes, dual tetramer staining with APC-labelled DR04:01/Phleum pratense tetramers and PE-labelled DR04:01/Pooideae grass homolog tetramers was assessed to identify cross-reactivity among allergen-specific DR04:01-restricted T-cells in six subjects. Direct ex vivo staining enabled the comparison of frequency and phenotype of different Pooideae grass-pollen reactive T-cells. Intracellular cytokine staining (ICS) assays were also used to examine phenotypes of these T-cells. T-cells with various degrees of cross-reactive profiles could be detected. Poa p 1 97-116 , Lol p 1 221-240 , Lol p 5a 199-218 , and Poa p 5a 199-218 were identified as minimally cross-reactive T-cell epitopes that do not show cross-reactivity to Phl p 1 and Phl p 5a epitopes. Ex vivo tetramer staining assays demonstrated T-cells that recognized these minimally cross-reactive T-cell epitopes are present in Grass-pollen-allergic subjects. Our results suggest that not all Pooideae grass epitopes with sequence homology are cross-reactive. Non-cross-reactive T-cells with comparable frequency, phenotype and functionality to Phl p-specific T-cells suggest that a multiple allergen system should be considered for immunotherapy instead of a mono-allergen system. © 2014 John Wiley & Sons Ltd.

Effects of prefrontal bipolar and high-definition transcranial direct current stimulation on cortical reactivity and working memory in healthy adults.

PubMed

Hill, Aron T; Rogasch, Nigel C; Fitzgerald, Paul B; Hoy, Kate E

2017-05-15

Transcranial direct current stimulation (tDCS) is a well-recognised neuromodulatory technology which has been shown to induce short-lasting changes in motor-cortical excitability. The recent and rapid expansion of tDCS into the cognitive domain, however, necessitates deeper mechanistic understanding of its neurophysiological effects over non-motor brain regions. The present study utilised transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) to probe the immediate and longer-term effects of both a bipolar (BP-tDCS) and more focal 4×1 High-Definition tDCS (HD-tDCS) montage applied over the left DLPFC on TMS-evoked potentials (TEPs) and oscillations in 19 healthy adult participants. 2-back working memory (WM) performance was also assessed as a marker of cognitive function. Region of interest (ROI) analyses taken from the F1 electrode directly adjacent to the stimulation site revealed increased P60 TEP amplitudes at this location 5min following BP-tDCS and 30min following HD-tDCS. Further global cluster based analyses of all scalp electrodes revealed widespread neuromodulatory changes following HD-tDCS, but not BP-tDCS, both five and 30min after stimulation, with reductions also detected in both beta and gamma oscillatory power over parieto-occipital channels 30min after stimulation. No significant changes in WM performance were observed following either HD-tDCS or BP-tDCS. This study highlights the capacity for single-session prefrontal anodal tDCS montages to modulate neurophysiological processes, as assessed with TMS-EEG. Copyright © 2017 Elsevier Inc. All rights reserved.

Reactive polymer fused deposition manufacturing

DOEpatents

Kunc, Vlastimil; Rios, Orlando; Love, Lonnie J.; Duty, Chad E.; Johs, Alexander

2017-05-16

Methods and compositions for additive manufacturing that include reactive or thermosetting polymers, such as urethanes and epoxies. The polymers are melted, partially cross-linked prior to the depositing, deposited to form a component object, solidified, and fully cross-linked. These polymers form networks of chemical bonds that span the deposited layers. Application of a directional electromagnetic field can be applied to aromatic polymers after deposition to align the polymers for improved bonding between the deposited layers.

Identification and Characterization of Breast Tumor Associated Antigens

DTIC Science & Technology

1998-08-01

detection. It has been shown that tumor bearing individuals often develop a limited immune response to their tumor. The production of antibodies directed...Sigma]) and incubated with alkaline phosphate-conjugated goat anti-human IgG (H+L) antibodies (Jackson Labs) at a dilution of 1:5,000 for one hour at...identified during plaque purification by testing the plaque for reactivity with secondary antibody alone. Plaques which are reactive with secondary antibody

Sputtered Gum metal thin films showing bacterial inactivation and biocompatibility.

PubMed

Achache, S; Alhussein, A; Lamri, S; François, M; Sanchette, F; Pulgarin, C; Kiwi, J; Rtimi, S

2016-10-01

Super-elastic Titanium based thin films Ti-23Nb-0.7Ta-2Zr-(O) (TNTZ-O) and Ti-24Nb-(N) (TN-N) (at.%) were deposited by direct current magnetron sputtering (DCMS) in different reactive atmospheres. The effects of oxygen doping (TNTZ-O) and/or nitrogen doping (TN-N) on the microstructure, mechanical properties and biocompatibility of the as-deposited coatings were investigated. Nano-indentation measurements show that, in both cases, 1sccm of reactive gas in the mixture is necessary to reach acceptable values of hardness and Young's modulus. Mechanical properties are considered in relation to the films compactness, the compressive stress and the changes in the grain size. Data on Bacterial inactivation and biocompatibility are reported in this study. The biocompatibility tests showed that O-containing samples led to higher cells proliferation. Bacterial inactivation was concomitant with the observed pH and surface potential changes under light and in the dark. The increased cell fluidity leading to bacterial lysis was followed during the bacterial inactivation time. The increasing cell wall fluidity was attributed to the damage of the bacterial outer cell which losing its capacity to regulate the ions exchange in and out of the bacteria. Copyright © 2016 Elsevier B.V. All rights reserved.

Flaviviruses in Europe: Complex Circulation Patterns and Their Consequences for the Diagnosis and Control of West Nile Disease

PubMed Central

Beck, Cécile; Jimenez-Clavero, Miguel Angel; Leblond, Agnès; Durand, Benoît; Nowotny, Norbert; Leparc-Goffart, Isabelle; Zientara, Stéphan; Jourdain, Elsa; Lecollinet, Sylvie

2013-01-01

In Europe, many flaviviruses are endemic (West Nile, Usutu, tick-borne encephalitis viruses) or occasionally imported (dengue, yellow fever viruses). Due to the temporal and geographical co-circulation of flaviviruses in Europe, flavivirus differentiation by diagnostic tests is crucial in the adaptation of surveillance and control efforts. Serological diagnosis of flavivirus infections is complicated by the antigenic similarities among the Flavivirus genus. Indeed, most flavivirus antibodies are directed against the highly immunogenic envelope protein, which contains both flavivirus cross-reactive and virus-specific epitopes. Serological assay results should thus be interpreted with care and confirmed by comparative neutralization tests using a panel of viruses known to circulate in Europe. However, antibody cross-reactivity could be advantageous in efforts to control emerging flaviviruses because it ensures partial cross-protection. In contrast, it might also facilitate subsequent diseases, through a phenomenon called antibody-dependent enhancement mainly described for dengue virus infections. Here, we review the serological methods commonly used in WNV diagnosis and surveillance in Europe. By examining past and current epidemiological situations in different European countries, we present the challenges involved in interpreting flavivirus serological tests and setting up appropriate surveillance programs; we also address the consequences of flavivirus circulation and vaccination for host immunity. PMID:24225644

External quality assurance in nongynecologic cytology: The Australasian experience.

PubMed

Shield, Paul W; Frost, Felicity; Finnimore, Jo L; Wright, R Gordon; Cummings, Margaret C

2017-05-01

The Royal College of Pathologists of Australasia Cytopathology Quality Assurance Program has operated an external quality assurance program in nongynecologic cytopathology since 1993. Glass slide preparations of a wide range of nongynecologic cases were circulated to approximately 200 cytopathology laboratories in 16 countries. General nongynecologic cytology cases were manufactured from residual specimens after routine diagnosis. Fine-needle aspiration (FNA) cases were made by sampling fresh tissue and making direct specimens. The majority of cases consisted of both air-dried and fixed preparations. Results returned to laboratories included illustrated case discussions highlighting diagnostic features, key differential diagnoses, and useful adjunctive tests. The current study reviewed >22,000 results for 123 nongynecologic cases. Cases found to cause the most diagnostic difficulties included serous effusion cases with metastatic carcinoma in a dispersed pattern, well-differentiated carcinoma, and cellular reactive cases; urine specimens with sparse malignant cells; reactive pneumocytes in a bronchoalveolar lavage; breast FNA cases with papillary lesions; gestational specimens; and fibroadenoma. FNA specimens from the lung and thyroid, particularly papillary thyroid carcinoma, generally were well reported. The use of multiple preparations of the same specimen has allowed interlaboratory comparison, and the quality assurance program has played an educational role as well as informing the laboratory accreditation process. Cancer Cytopathol 2017;125:349-361. © 2017 American Cancer Society. © 2017 American Cancer Society.

Puzzling and ambivalent roles of malarial infections in cancer development and progression.

PubMed

Faure, Eric

2016-12-01

Scientific evidence strongly suggests that parasites are directly or indirectly associated with carcinogenesis in humans. However, studies have also indicated that parasites or their products might confer resistance to tumour growth. Plasmodium protozoa, the causative agents of malaria, exemplify the ambivalent link between parasites and cancer. Positive relationships between malaria and virus-associated cancers are relatively well-documented; for example, malaria can reactivate the Epstein-Barr Virus, which is the known cause of endemic Burkitt lymphoma. Nevertheless, possible anti-tumour properties of malaria have also been reported and, interestingly, this disease has long been thought to be beneficial to patients suffering from cancers. Current knowledge of the potential pro- and anti-cancer roles of malaria suggests that, contrary to other eukaryotic parasites affecting humans, Plasmodium-related cancers are principally lymphoproliferative disorders and attributable to virus reactivation, whereas, similar to other eukaryotic parasites, the anti-tumour effects of malaria are primarily associated with carcinomas and certain sarcomas. Moreover, malarial infection significantly suppresses murine cancer growth by inducing both innate and specific adaptive anti-tumour responses. This review aims to present an update regarding the ambivalent association between malaria and cancer, and further studies may open future pathways to develop novel strategies for anti-cancer therapies.

Reactive sputter deposition of piezoelectric Sc 0.12Al 0.88N for contour mode resonators

DOE PAGES

Henry, Michael David; Young, Travis Ryan; Douglas, Erica Ann; ...

2018-05-11

Substitution of Al by Sc has been predicted and demonstrated to improve the piezoelectric response in AlN for commercial market applications in radio frequency filter technologies. Although cosputtering with multiple targets have achieved Sc incorporation in excess of 40%, industrial processes requiring stable single target sputtering are currently limited. A major concern with sputter deposition of ScAl is the control over the presence of non-c-axis oriented crystal growth, referred to as inclusions here, while simultaneously controlling film stress for suspended microelectromechanical systems (MEMS) structures. In this paper, we describe 12.5% ScAl single target reactive sputter deposition process and establishes amore » direct relationship between the inclusion occurrences and compressive film stress allowing for the suppression of the c-axis instability on silicon (100) and Ti/TiN/AlCu seeding layers. An initial high film stress, for suppressing inclusions, is then balanced with a lower film stress deposition to control total film stress to prevent Euler buckling of suspended MEMS devices. Contour mode resonators fabricated using these films demonstrate effective coupling coefficients up to 2.7% with figures of merit of 42. Finally, this work provides a method to establish inclusion free films in ScAlN piezoelectric films for good quality factor devices.« less

Reactive sputter deposition of piezoelectric Sc 0.12Al 0.88N for contour mode resonators

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

Henry, Michael David; Young, Travis Ryan; Douglas, Erica Ann

Substitution of Al by Sc has been predicted and demonstrated to improve the piezoelectric response in AlN for commercial market applications in radio frequency filter technologies. Although cosputtering with multiple targets have achieved Sc incorporation in excess of 40%, industrial processes requiring stable single target sputtering are currently limited. A major concern with sputter deposition of ScAl is the control over the presence of non-c-axis oriented crystal growth, referred to as inclusions here, while simultaneously controlling film stress for suspended microelectromechanical systems (MEMS) structures. In this paper, we describe 12.5% ScAl single target reactive sputter deposition process and establishes amore » direct relationship between the inclusion occurrences and compressive film stress allowing for the suppression of the c-axis instability on silicon (100) and Ti/TiN/AlCu seeding layers. An initial high film stress, for suppressing inclusions, is then balanced with a lower film stress deposition to control total film stress to prevent Euler buckling of suspended MEMS devices. Contour mode resonators fabricated using these films demonstrate effective coupling coefficients up to 2.7% with figures of merit of 42. Finally, this work provides a method to establish inclusion free films in ScAlN piezoelectric films for good quality factor devices.« less

Reactive sputter deposition of piezoelectric Sc 0.12Al 0.88N for contour mode resonators

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

Henry, Michael David; Young, Travis Ryan; Douglas, Erica Ann

Substitution of Al by Sc has been predicted and demonstrated to improve the piezoelectric response in AlN for commercial market applications in radio frequency filter technologies. Although cosputtering with multiple targets have achieved Sc incorporation in excess of 40%, industrial processes requiring stable single target sputtering are currently limited. A major concern with sputter deposition of ScAl is the control over the presence of non-c-axis oriented crystal growth, referred to as inclusions here, while simultaneously controlling film stress for suspended microelectromechanical systems (MEMS) structures. This work describes 12.5% ScAl single target reactive sputter deposition process and establishes a direct relationshipmore » between the inclusion occurrences and compressive film stress allowing for the suppression of the c-axis instability on silicon (100) and Ti/TiN/AlCu seeding layers. An initial high film stress, for suppressing inclusions, is then balanced with a lower film stress deposition to control total film stress to prevent Euler buckling of suspended MEMS devices. Contour mode resonators fabricated using these films demonstrate effective coupling coefficients up to 2.7% with figures of merit of 42. Furthermore, this work provides a method to establish inclusion free films in ScAlN piezoelectric films for good quality factor devices.« less

Review of pore network modelling of porous media: Experimental characterisations, network constructions and applications to reactive transport.

PubMed

Xiong, Qingrong; Baychev, Todor G; Jivkov, Andrey P

2016-09-01

Pore network models have been applied widely for simulating a variety of different physical and chemical processes, including phase exchange, non-Newtonian displacement, non-Darcy flow, reactive transport and thermodynamically consistent oil layers. The realism of such modelling, i.e. the credibility of their predictions, depends to a large extent on the quality of the correspondence between the pore space of a given medium and the pore network constructed as its representation. The main experimental techniques for pore space characterisation, including direct imaging, mercury intrusion porosimetry and gas adsorption, are firstly summarised. A review of the main pore network construction techniques is then presented. Particular focus is given on how such constructions are adapted to the data from experimentally characterised pore systems. Current applications of pore network models are considered, with special emphasis on the effects of adsorption, dissolution and precipitation, as well as biomass growth, on transport coefficients. Pore network models are found to be a valuable tool for understanding and predicting meso-scale phenomena, linking single pore processes, where other techniques are more accurate, and the homogenised continuum porous media, used by engineering community. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Nanoparticle-Formulated Curcumin Prevents Posttherapeutic Disease Reactivation and Reinfection with Mycobacterium tuberculosis following Isoniazid Therapy

PubMed Central

Tousif, Sultan; Singh, Dhiraj Kumar; Mukherjee, Sitabja; Ahmad, Shaheer; Arya, Rakesh; Nanda, Ranjan; Ranganathan, Anand; Bhattacharyya, Maitree; Van Kaer, Luc; Kar, Santosh K.; Das, Gobardhan

2017-01-01

Curcumin, the bioactive component of turmeric also known as “Indian Yellow Gold,” exhibits therapeutic efficacy against several chronic inflammatory and infectious diseases. Even though considered as a wonder drug pertaining to a myriad of reported benefits, the translational potential of curcumin is limited by its low systemic bioavailability due to its poor intestinal absorption, rapid metabolism, and rapid systemic elimination. Therefore, the translational potential of this compound is specifically challenged by bioavailability issues, and several laboratories are making efforts to improve its bioavailability. We developed a simple one-step process to generate curcumin nanoparticles of ~200 nm in size, which yielded a fivefold enhanced bioavailability in mice over regular curcumin. Curcumin nanoparticles drastically reduced hepatotoxicity induced by antitubercular antibiotics during treatment in mice. Most interestingly, co-treatment of nanoparticle-formulated curcumin along with antitubercular antibiotics dramatically reduced the risk for disease reactivation and reinfection, which is the major shortfall of current antibiotic treatment adopted by Directly Observed Treatment Short-course. Furthermore, nanoparticle-formulated curcumin significantly reduced the time needed for antibiotic therapy to obtain sterile immunity, thereby reducing the possibility of generating drug-resistant variants of the organisms. Therefore, adjunct therapy of nano-formulated curcumin with enhanced bioavailability may be beneficial to treatment of tuberculosis and possibly other diseases. PMID:28713372

Nutritional Countermeasures Targeting Reactive Oxygen Species in Cancer: From Mechanisms to Biomarkers and Clinical Evidence

PubMed Central

Samoylenko, Anatoly; Hossain, Jubayer Al; Mennerich, Daniela; Kellokumpu, Sakari; Hiltunen, Jukka Kalervo

2013-01-01

Abstract Reactive oxygen species (ROS) exert various biological effects and contribute to signaling events during physiological and pathological processes. Enhanced levels of ROS are highly associated with different tumors, a Western lifestyle, and a nutritional regime. The supplementation of food with traditional antioxidants was shown to be protective against cancer in a number of studies both in vitro and in vivo. However, recent large-scale human trials in well-nourished populations did not confirm the beneficial role of antioxidants in cancer, whereas there is a well-established connection between longevity of several human populations and increased amount of antioxidants in their diets. Although our knowledge about ROS generators, ROS scavengers, and ROS signaling has improved, the knowledge about the direct link between nutrition, ROS levels, and cancer is limited. These limitations are partly due to lack of standardized reliable ROS measurement methods, easily usable biomarkers, knowledge of ROS action in cellular compartments, and individual genetic predispositions. The current review summarizes ROS formation due to nutrition with respect to macronutrients and antioxidant micronutrients in the context of cancer and discusses signaling mechanisms, used biomarkers, and its limitations along with large-scale human trials. Antioxid. Redox Signal. 19, 2157–2196. PMID:23458328

Effectiveness of a self-administered intervention for criminal thinking: Taking a Chance on Change.

PubMed

Folk, Johanna B; Disabato, David J; Daylor, Jordan M; Tangney, June P; Barboza, Sharen; Wilson, John S; Bonieskie, Lynda; Holwager, James

2016-08-01

The current study tested the effectiveness of a self-administered, cognitive-behavioral intervention targeting criminal thinking for inmates in segregated housing: Taking a Chance on Change (TCC). Participants included 273 inmates in segregated housing at state correctional institutions. Reductions in criminal thinking, as assessed by the Psychological Inventory of Criminal Styles-Simplified Version, were found in the general criminal thinking score as well as the proactive and reactive composite scores. Examination of demographic predictors of change (i.e., age, years of education, length of sentence) revealed older and more educated participants decreased in criminal thinking more than younger and less educated participants. For a subset of 48 inmates, completion of TCC was associated with significant reduction of disciplinary infractions. Reductions in reactive criminal thinking predicted reductions in disciplinary infractions. Although further research is needed to determine the effectiveness of TCC in reducing recidivism, the reductions in criminal thinking and disordered conduct suggest this is a promising intervention and mode of treatment delivery. By utilizing self-directed study at an accessible reading level, the intervention is uniquely suited to a correctional setting where staff and monetary resources are limited and security and operational issues limit the feasibility of traditional cognitive-behavioral group treatment. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Laser speckle imaging allows real-time intraoperative blood flow assessment during neurosurgical procedures.

PubMed

Hecht, Nils; Woitzik, Johannes; König, Susanne; Horn, Peter; Vajkoczy, Peter

2013-07-01

Currently, there is no adequate technique for intraoperative monitoring of cerebral blood flow (CBF). To evaluate laser speckle imaging (LSI) for assessment of relative CBF, LSI was performed in 30 patients who underwent direct surgical revascularization for treatment of arteriosclerotic cerebrovascular disease (ACVD), Moyamoya disease (MMD), or giant aneurysms, and in 8 control patients who underwent intracranial surgery for reasons other than hemodynamic compromise. The applicability and sensitivity of LSI was investigated through baseline perfusion and CO2 reactivity testing. The dynamics of LSI were assessed during bypass test occlusion and flow initiation procedures. Laser speckle imaging permitted robust (pseudo-) quantitative assessment of relative microcirculatory flow and standard bypass grafting resulted in significantly higher postoperative baseline perfusion values in ACVD and MMD. The applicability and sensitivity of LSI was shown by a significantly reduced CO2 reactivity in ACVD (9.6±9%) and MMD (8.5±8%) compared with control (31.2±5%; P<0.0001). In high- and intermediate-flow bypass patients, LSI was characterized by a dynamic real-time response to acute perfusion changes and ultimately confirmed a sufficient flow substitution through the bypass graft. Thus, LSI can be used for sensitive and continuous, non-invasive real-time visualization and measurement of relative cortical CBF in excellent spatial-temporal resolution.

Characterization of thin MoO3 films formed by RF and DC-magnetron reactive sputtering for gas sensor applications

NASA Astrophysics Data System (ADS)

Yordanov, R.; Boyadjiev, S.; Georgieva, V.; Vergov, L.

2014-05-01

The present work discusses a technology for deposition and characterization of thin molybdenum oxide (MoOx, MoO3) films studied for gas sensor applications. The samples were produced by reactive radio-frequency (RF) and direct current (DC) magnetron sputtering. The composition and microstructure of the films were studied by XPS, XRD and Raman spectroscopy, the morphology, using high resolution SEM. The research was focused on the sensing properties of the sputtered thin MoO3 films. Highly sensitive gas sensors were implemented by depositing films of various thicknesses on quartz resonators. Making use of the quartz crystal microbalance (QCM) method, these sensors were capable of detecting changes in the molecular range. Prototype QCM structures with thin MoO3 films were tested for sensitivity to NH3 and NO2. Even in as-deposited state and without heating the substrates, these films showed good sensitivity. Moreover, no additional thermal treatment is necessary, which makes the production of such QCM gas sensors simple and cost-effective, as it is fully compatible with the technology for producing the initial resonator. The films are sensitive at room temperature and can register concentrations as low as 50 ppm. The sorption is fully reversible, the films are stable and capable of long-term measurements.

The potential for using slags activated with near neutral salts as immobilisation matrices for nuclear wastes containing reactive metals

NASA Astrophysics Data System (ADS)

Bai, Y.; Collier, N. C.; Milestone, N. B.; Yang, C. H.

2011-06-01

The UK currently uses composite blends of Portland cement and other inorganic cementitious material such as blastfurnace slag and pulverised fuel ash to encapsulate or immobilise intermediate and low level radioactive wastes. Typically levels up 9:1 blast furnace slag:Portland cement or 4:1 pulverised fuel ash:Portland cement are used. Whilst these systems offer many advantages, their high pH causes corrosion of various metallic intermediate level radioactive wastes. To address this issue, lower pH/weakly alkaline cementitious systems have to be explored. While the blast furnace slag:Portland cement system is referred to as a composite cement system, the underlying reaction is actually an indirect activation of the slag hydration by the calcium hydroxide generated by the cement hydration, and by the alkali ions and gypsum present in the cement. However, the slag also can be activated directly with activators, creating a system known as alkali-activated slag. Whilst these activators used are usually strongly alkaline, weakly alkaline and near neutral salts can also be used. In this paper, the potential for using weakly alkaline and near neutral salts to activate slag in this manner is reviewed and discussed, with particular emphasis placed on the immobilisation of reactive metallic nuclear wastes.

Effectiveness of a self-administered intervention for criminal thinking: Taking a chance on change

PubMed Central

Folk, Johanna B.; Disabato, David J.; Daylor, Jordan M.; Tangney, June P.; Barboza, Sharen; Wilson, John S.; Bonieskie, Lynda; Holwager, James

2016-01-01

The current study tested the effectiveness of a self-administered, cognitive-behavioral intervention targeting criminal thinking for inmates in segregated housing: Taking a Chance on Change (TCC). Participants included 273 inmates in segregated housing at state correctional institutions. Reductions in criminal thinking, as assessed by the Psychological Inventory of Criminal Styles-Simplified Version, were found in the general criminal thinking score as well as the proactive and reactive composite scores. Examination of demographic predictors of change (i.e., age, years of education, length of sentence) revealed older and more educated participants decreased in criminal thinking more than younger and less educated participants. For a subset of 48 inmates, completion of TCC was associated with significant reduction of disciplinary infractions. Reductions in reactive criminal thinking predicted reductions in disciplinary infractions. Although further research is needed to determine the effectiveness of TCC in reducing recidivism, the reductions in criminal thinking and disordered conduct suggest this is a promising intervention and mode of treatment delivery. By utilizing self-directed study at an accessible reading level, the intervention is uniquely suited to a correctional setting where staff and monetary resources are limited and security and operational issues limit the feasibility of traditional cognitive-behavioral group treatment. PMID:27243111

Adaptability Evaluation of GCPVS under Voltage Sag

NASA Astrophysics Data System (ADS)

Wang, Li

2018-03-01

A basic LVRT strategy widely used in engineering practice is taken in this paper and manages to ride through both symmetrical and asymmetrical sag conditions. Precise current reference is calculate based on the reactive current curve in China National Grid Code, deration of current is realized in this way by eliminating NS current. The role of hardware protection has been discussed in detail.

Activation of host immune responses in neonatal calves and interference with TB diagnostics after immunization with a commercial heat-killed vaccine

USDA-ARS?s Scientific Manuscript database

A major drawback of current whole-cell vaccines for Mycobacterium avium subsp. paratuberculosis is the potential interference with diagnostic tests for bovine tuberculosis and paratuberculosis. The current study was designed to explore cross-reactivity of the current USDA commercial vaccine for MAP ...

Activation of host immune responses in neonatal calves and interference with TB diagnostics after immunization with a commercial heat-killed vaccine

USDA-ARS?s Scientific Manuscript database

A major drawback of current whole-cell vaccines for Mycobacterium avium subsp. paratuberculosis (MAP) is the potential interference with diagnostic tests for bovine tuberculosis and paratuberculosis. The current study was designed to explore cross-reactivity of the current USDA commercial vaccine fo...

Reactivity of coal in direct hydrogenation processes: Technical progress report, March-May 1987

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

Baldwin, R.M.; Miller, R.L.

Research during the past quarter centered on continuation of two facets related to the study of coal reactivity in direct hydrogenation liquefaction processes. Five coals from the Argonne Premium coal collection were liquefied at three temperature levels in order to gather data for kinetic analysis purposes. Conversion of these coals to THF-, toluene-, and hexane-solubles was determined at temperatures of 425, 400, and 375 C, and nominal reaction times of 3, 5, 10, 15, and 40 minutes in the microautoclave batch reaction system. Preliminary mathematical modeling of the data using simple irreversible rate expressions and more complex formulations based onmore » a statistical distribution of activation energies was initiated in order to investigate the feasibility of utilizing activation energy as an additional reactivity screening factor. Use of complex models such as the Anthony-Howard formulation for purposes of activation energy determination from liquefaction data at one temperature level was further examined. Five of the 21 coals from the Penn State Premium coal sample bank were liquefied at the standard reactivity screening conditions, and the rate and extent of conversion to THF-, and toluene-, and hexane-solubles quantified. These data were added to the existing data base containing similar information for the prior coal suites from the Exxon and Argonne collections, and preliminary correlational efforts for reactivity vs. coal properties were initiated. Prior conclusions regarding the effect of rank on the rate and extent of conversion were qualitatively verified from the data collected. 1 ref., 13 figs., 2 tabs.« less

Reactive astrocyte COX2-PGE2 production inhibits oligodendrocyte maturation in neonatal white matter injury.

PubMed

Shiow, Lawrence R; Favrais, Geraldine; Schirmer, Lucas; Schang, Anne-Laure; Cipriani, Sara; Andres, Christian; Wright, Jaclyn N; Nobuta, Hiroko; Fleiss, Bobbi; Gressens, Pierre; Rowitch, David H

2017-12-01

Inflammation is a major risk factor for neonatal white matter injury (NWMI), which is associated with later development of cerebral palsy. Although recent studies have demonstrated maturation arrest of oligodendrocyte progenitor cells (OPCs) in NWMI, the identity of inflammatory mediators with direct effects on OPCs has been unclear. Here, we investigated downstream effects of pro-inflammatory IL-1β to induce cyclooxygenase-2 (COX2) and prostaglandin E2 (PGE2) production in white matter. First, we assessed COX2 expression in human fetal brain and term neonatal brain affected by hypoxic-ischemic encephalopathy (HIE). In the developing human brain, COX2 was expressed in radial glia, microglia, and endothelial cells. In human term neonatal HIE cases with subcortical WMI, COX2 was strongly induced in reactive astrocytes with "A2" reactivity. Next, we show that OPCs express the EP1 receptor for PGE2, and PGE2 acts directly on OPCs to block maturation in vitro. Pharmacologic blockade with EP1-specific inhibitors (ONO-8711, SC-51089), or genetic deficiency of EP1 attenuated effects of PGE2. In an IL-1β-induced model of NWMI, astrocytes also exhibit "A2" reactivity and induce COX2. Furthermore, in vivo inhibition of COX2 with Nimesulide rescues hypomyelination and behavioral impairment. These findings suggest that neonatal white matter astrocytes can develop "A2" reactivity that contributes to OPC maturation arrest in NWMI through induction of COX2-PGE2 signaling, a pathway that can be targeted for neonatal neuroprotection. © 2017 Wiley Periodicals, Inc.

Use of Adaptive Injection Strategies to Increase the Full Load Limit of RCCI Operation

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

Hanson, Reed; Ickes, Andrew; Wallner, Thomas

2015-01-01

Dual-fuel combustion using port-injection of low reactivity fuel combined with direct injection of a higher reactivity fuel, otherwise known as Reactivity Controlled Compression Ignition (RCCI), has been shown as a method to achieve low-temperature combustion with moderate peak pressure rise rates, low engine-out soot and NOx emissions, and high indicated thermal efficiency. A key requirement for extending to high-load operation is moderating the reactivity of the premixed charge prior to the diesel injection. One way to accomplish this is to use a very low reactivity fuel such as natural gas. In this work, experimental testing was conducted on a 13Lmore » multi-cylinder heavy-duty diesel engine modified to operate using RCCI combustion with port injection of natural gas and direct injection of diesel fuel. Engine testing was conducted at an engine speed of 1200 RPM over a wide variety of loads and injection conditions. The impact on dual-fuel engine performance and emissions with respect to varying the fuel injection parameters is quantified within this study. The injection strategies used in the work were found to affect the combustion process in similar ways to both conventional diesel combustion and RCCI combustion for phasing control and emissions performance. As the load is increased, the port fuel injection quantity was reduced to keep peak cylinder pressure and maximum pressure rise rate under the imposed limits. Overall, the peak load using the new injection strategy was shown to reach 22 bar BMEP with a peak brake thermal efficiency of 47.6%.« less