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Strength reactivity

Jose A Fernandez-Leon, Bryan J Hansen, Valentin Dragoi
Natural viewing often consists of sequences of brief fixations to image patches of different structure. Whether and how briefly presented sequential stimuli are encoded in a temporal-position manner is poorly understood. Here, we performed multiple-electrode recordings in the visual cortex (area V4) of nonhuman primates (Macaca mulatta) viewing a sequence of 7 briefly flashed natural images, and measured correlations between the cue-triggered population response in the presence and absence of the stimulus. Surprisingly, we found significant correlations for images occurring at the beginning and the end of a sequence, but not for those in the middle...
June 20, 2017: Cerebral Cortex
Alexander T Baugh, Sarah C Davidson, Michaela Hau, Kees van Oers
Variation in the reactivity of the endocrine stress axis is thought to underlie aspects of persistent individual differences in behavior (i.e. animal personality). Previous studies, however, have focused largely on estimating baseline or peak levels of glucocorticoids (CORT), often in captive animals. In contrast, the temporal dynamics of the HPA axis-how quickly it turns on and off, for example-may better indicate how an individual copes with stressors. Moreover, these HPA components might be correlated, thereby representing endocrine suites...
June 18, 2017: General and Comparative Endocrinology
Chia-Hua Wu, Keigo Ito, Allyson Buytendyk, Kit Hansell Bowen, Judy I Wu
Surprisingly large "resonance-assistance" effects may explain how some enzymes form extremely short, strong hydrogen bonds to stabilize reactive oxyanion intermediates and facilitate catalysis. Computational models for several enzymic residue-substrate interactions reveal that when a π-conjugated, proton donor (XH) forms a hydrogen bond to a charged substrate (Y-), XH can become significantly more π-electron delocalized, and this "extra" stabilization may boost the [XH…Y-] hydrogen bond strength by up to 15 kcal/mol...
June 21, 2017: Biochemistry
Ruirun Chen, Deshuang Zheng, Tengfei Ma, Hongsheng Ding, Yanqing Su, Jingjie Guo, Hengzhi Fu
In spite of their high temperature and reactivity, the binary TiAl alloys are successfully imposed by the ultrasonic irradiation and the microstructure evolution, solidification behaviors and mechanical properties are elaborately investigated. After ultrasonic irradiation, a high quality ingot without shrinkage defects and element segregation is obtained and the coarse dendrite structure is well modified into fine non-dendrite globular grains. The coarse lamellar colony and lamellar space of Ti44Al alloy is refined from 685μm to 52μm and 1185nm to 312nm, respectively (similarly, 819μm to 102μm and 2085nm to 565nm for Ti48Al alloy)...
September 2017: Ultrasonics Sonochemistry
Mehdi Shakourian-Fard, Hadiseh Heydari, Ganesh Kamath
Defect engineering could potentially allow for dramatic tuning of optoelectronic properties of two-dimensional materials. With the help of density functional theory (DFT) calculations, we present a systematic study of the DNA Nucleobases (NBs) adsorbed on hexagonal boron-nitride nanoflake (h-BNNF) and boron and nitrogen monovacancies. The presence of such VN and VB defects increases the binding strength of NBs by 9 kcal/mol and 34 kcal/mol, respectively (h-BNNF-VB> h-BNNF-VN> h-BNNF). A more negative electrostatic potential at the B vacancy-site makes h-BNNF-VB surface more reactive than h-BNNF-VN surface enabling H-bonding interactions with NBs...
June 20, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Zhenchao Zhao, Hui Shi, Chuan Wan, Mary Y Hu, Yuanshuai Liu, Donghai Mei, Donald M Camaioni, Jian Zhi Hu, Johannes A Lercher
The reaction mechanism of solid-acid-catalyzed phenol alkylation with cyclohexanol and cyclohexene in the apolar solvent decalin has been studied using in situ (13)C MAS NMR spectroscopy. Phenol alkylation with cyclohexanol sets in only after a majority of cyclohexanol is dehydrated to cyclohexene. As phenol and cyclohexanol show similar adsorption strength, this strict reaction sequence is not caused by the limited access of phenol to cyclohexanol, but is due to the absence of a reactive electrophile as long as a significant fraction of cyclohexanol is present...
June 19, 2017: Journal of the American Chemical Society
Shunsuke Tomita, Sayaka Ishihara, Ryoji Kurita
The identification of post-translational modifications (PTMs) in proteins has been of particular interest in the elucidation of human diseases and the improvement of therapeutic proteins. Herein, we report a novel strategy toward the construction of fingerprint-based PTM sensing systems as an alternative to conventional specific recognition tools. Our strategy is based on poly-L-lysine (PLL) derivatives with two distinct properties suitable to fingerprint-based protein sensing: i) a "turn-on" fluorescent signal upon binding to proteins, and ii) condition-dependent cross-reactivity toward proteins and PTMs...
June 19, 2017: ACS Applied Materials & Interfaces
Marissa H G Gerards, Christopher McCrum, Avril Mansfield, Kenneth Meijer
Falls are a leading cause of injury, hospitalization and even death among older adults. Although various strength and balance exercise interventions have shown moderate reductions in falls incidence among healthy older adults, no significant falls incidence improvements have been consistently seen in frail older adults or in patient groups with an increased falls risk (e.g. people with Parkinson's disease and stroke). This might be due to a lack of task specificity of previous exercise interventions to the recovery actions required to prevent a fall...
June 16, 2017: Geriatrics & Gerontology International
Nur Hamizah Mohtor, Mohd Hafiz Dzarfan Othman, Ahmad Fauzi Ismail, Mukhlis A Rahman, Juhana Jaafar, Nur Awanis Hashim
Despite its extraordinary price, ceramic membrane can still be able to surpass polymeric membrane in the applications that require high temperature and pressure conditions, as well as harsh chemical environment. In order to alleviate the high cost of ceramic material that still becomes one of the major factors that contributes to the high production cost of ceramic membrane, various attempts have been made to use low cost ceramic materials as alternatives to well-known expensive ceramic materials such as alumina, silica, and zirconia in the fabrication of ceramic membrane...
June 15, 2017: Environmental Science and Pollution Research International
Omid Zabihi, Mojtaba Ahmadi, Tahereh Abdollahi, Saeid Nikafshar, Minoo Naebe
Scale-up manufacturing of engineered graphene-like nanomaterials to deliver the industry needs for development of high-performance polymer nanocomposites still remains a challenge. Herein, we introduce a quick and cost-effective approach to scalable production of functionalized graphite nanoplatelets using "kitchen blender" approach and Diels-Alder chemistry. We have shown that, in a solvent-free process and through a cycloaddition mechanism, maleic anhydride can be grafted onto the edge-localized electron rich active sites of graphite nanoplatelets (GNP) resulting from high collision force, called "graphite collision-induced activation"...
June 15, 2017: Scientific Reports
Naruporn Monmaturapoj, Autcharaporn Srion, Prasert Chalermkarnon, Suthawan Buchatip, Atitsa Petchsuk, Warobon Noppakunmongkolchai, Katanchalee Mai-Ngam
A composite of 70/30 poly(lactic acid)/hydroxyapatite was systematically prepared using various amounts of glycidyl methacrylate as reactive compatibilizer or Joncryl ADR®-4368 containing nine glycidyl methacrylate functions as a chain extension/branching agent to improve the mechanical and biological properties for suitable usage as internal bone fixation devices. The effect of glycidyl methacrylate/Joncryl on mechanical properties of poly(lactic acid)/hydroxyapatite was investigated through flexural strength...
January 1, 2017: Journal of Biomaterials Applications
T Sergan, I Dozov, V Sergan, R Voss
We measured the Rapini-Papoular polar anchoring strength coefficient W for 4^{'}-pentyl-4-cyanobiphenyl (5CB) on alignment layers formed by the reactive mesogen photopolymers RM 257, RM 82, and RM 84 [4,4^{'}-bis(acryloyl)biphenyl] (by Merck). These materials are commonly used for the photostabilization of the liquid crystal (LC) director in the bulk as well as at the surface of the LC layer via the formation of a loose polymer network that captures the director orientation. We developed a method of fabrication of alignment layers from these polymers, and estimated W from the measurements of the optical retardation as a function of applied voltage in uniformly aligned cells...
May 2017: Physical Review. E
Shahab Kashani Rahimi, Robabeh Aeinehvand, Kyoungtae Kim, Joshua U Otaigbe
Poly(butylene adipate-co-terephthalate) (PBAT) was first chemically modified via free radical grafting with maleic anhydride (MA) and the MA-g-PBAT graft copolymer was then used as a matrix material to obtain cellulose nanocrystal (CNC)-reinforced MA-g-PBAT bio-nanocomposites via reactive extrusion process to accelerate efforts to develop functional bioabsorbable polymer nanocomposites with improved properties. The molecular structure of the PBAT after chemical modification with maleic anhydride was confirmed by 1H NMR and FTIR spectroscopy...
June 15, 2017: Biomacromolecules
Michael W Munks, Alana M Montoya, Cameron M Pywell, Garrick Talmage, Anna Forssen, Teresa L Campbell, Donald D Dodge, John W Kappler, Philippa Marrack
Herpesviruses establish lifelong infections, normally characterized by prolonged periods of latency with intermittent episodes of viral reactivation. Feline herpesvirus-1 (FHV-1) infects domestic cats, and epidemiological studies indicate that many or most domestic cats are exposed to FHV-1, but the strength and longevity of the antibody response to FHV-1 is not fully characterized. Here we describe development of an ELISA, using lysates of cat cells infected with FHV-1, that measure feline antibodies against FHV-1...
June 2017: Veterinary Immunology and Immunopathology
Shirin Kalyan, Millan S Patel, Elaine Kingwell, Hélène C F Côté, Danmei Liu, Jerilynn C Prior
Chronic inflammation predisposes to poor bone health. Women with polycystic ovary syndrome (PCOS) experience androgen excess, ovulatory disturbances, insulin resistance, abdominal adiposity and chronic inflammation. Our objective was to investigate the relationships among bone health parameters, chronic subclinical inflammation and anthropometric measures in premenopausal women with and without PCOS. In 61 premenopausal women, 22 women with PCOS and 39 controls, we assessed bone parameters (total hip bone mineral density [BMD] by dual-energy X-ray absorptiometry and radius strength-strain index [SSI] by peripheral quantitative computed tomography), inflammation (C-reactive protein/albumin), oxidative stress (leukocyte telomere length, urinary 8-hydroxydeoxyguanosine); hemoglobin A1c; anthropometric measures (body mass index, waist-to-height ratio, cross-sectional muscle area)...
June 13, 2017: Scientific Reports
John J McMahon, Paul A Jones, Timothy J Suchomel, Jason Lake, Paul Comfort
PURPOSE: The reactive strength index modified (RSImod) has been recently identified and validated as a method of monitoring countermovement jump (CMJ) performance. The kinetic and kinematic mechanisms that optimize a higher RSImod score are, however, currently unknown. The purpose of this study, therefore, was to compare entire CMJ force-, power-, velocity- and displacement-time curves (termed temporal phase analysis) of athletes who achieve high versus low RSImod scores. METHODS: Fifty-three professional male rugby league players performed three maximal effort CMJs on a force platform and variables of interest were calculated via forward dynamics...
June 12, 2017: International Journal of Sports Physiology and Performance
Hadi Ramezani-Dakhel, Nicholas M Bedford, Taylor J Woehl, Marc R Knecht, Rajesh R Naik, Hendrik Heinz
Colloidal metal nanocrystals find many applications in catalysis, energy conversion devices, and therapeutics. However, the nature of ligand interactions and implications on shape control have remained uncertain at the atomic scale. Large differences in peptide adsorption strength and facet specificity were found on flat palladium surfaces versus surfaces of nanoparticles of 2 to 3 nm size using accurate atomistic simulations with the Interface force field. Folding of longer peptides across many facets explains the formation of near-spherical particles with local surface disorder, in contrast to the possibility of nanostructures of higher symmetry with shorter ligands...
June 12, 2017: Nanoscale
Ralte Lalrempuia, Frida Breivik, Karl W Törnroos, Erwan Le Roux
Tetravalent zirconium complexes supported by tridentate bis-phenolate imidazolidin-2-ylidene (L1), imidazol-2-ylidene (L2) and benzimidazol-2-ylidene (L3) NHC ligands were synthesized and evaluated as precursors for the copolymerization of cyclohexene oxide (CHO) with CO2. While the reactivity of the imidazolidinium [H3L1] chloride salt with Zr(OiPr)4(HOiPr), and subsequent ligand exchanges with either (CH3)3SiCl or LiOiPr lead to a series of heteroleptic compounds (κ(3)-O,C,O-L1)Zr(X)2(THF) (X = Cl, OiPr), both imidazolium [H3L2] and benzimidazolium [H3L3] chloride salts give a mixture of homoleptic (κ(3)-O,C,O-NHC)2Zr and zwitterionic (κ(2)-O,O-HL)ZrCl2(OiPr) compounds along with traces or the absence of the heteroleptic intermediate (κ(3)-O,C,O-NHC)Zr(Cl)(OiPr)(THF)...
June 12, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
David Nora, Jorge Salluh, Ignacio Martin-Loeches, Pedro Póvoa
Biomarkers as C-reactive protein (CRP) and procalcitonin (PCT) emerged as tools to help clinicians to diagnose infection and to properly initiate and define the duration of antibiotic therapy. Several randomized controlled trials, including adult critically ill patients, showed that PCT-guided antibiotic stewardship was repeatedly associated with a decrease in the duration of antibiotic therapy with no apparent harm. There are however some relevant limitations in these trials namely the low rate of compliance of PCT-guided algorithms, the high rate of exclusion (without including common clinical situations and pathogens) and the long duration of antibiotic therapy in control groups...
May 2017: Annals of Translational Medicine
Marco Franco-Pérez, Carlos-A Polanco-Ramírez, Paul W Ayers, José L Gázquez, Alberto Vela
We define three new linear response indices with promising applications for bond reactivity using the mathematical framework of τ-CRT (finite temperature chemical reactivity theory). The τ-Fukui kernel is defined as the ratio between the fluctuations of the average electron density at two different points in the space and the fluctuations in the average electron number and is designed to integrate to the finite-temperature definition of the electronic Fukui function. When this kernel is condensed, it can be interpreted as a site-reactivity descriptor of the boundary region between two atoms...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
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