bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of PEGylation on Multivalent Binding: A Surface Plasmon Resonance and Isothermal Titration Calorimetry Study with Structurally Diverse PEG‐Dendritic GATG Copolymers
Authors: Fernandez‐Villamarin Marcos , Sousa‐Herves Ana , Correa Juan , Munoz Eva Maria , Taboada Pablo , Riguera Ricardo , Fernandez‐Megia Eduardo 
Published: February 2016

AbstractA general synthetic strategy to polyethylene glycol (PEG)‐dendritic block copolymers of the GATG (gallic acid–triethylene glycol) family is described from commercially available PEG of different molecular weights and architectures. Glycosylation of the resulting azide‐terminated copolymers with fucose by copper‐catalyzed azide–alkyne cycloaddition (CuAAC) afforded a toolbox to study the effect of PEG on the multivalent binding with the lectin UEA‐I by surface plasmon resonance (SPR, on surface) and isothermal titration calorimetry (ITC, in solution). Our results indicate that PEG reduces the affinity of glycodendrimers towards lectins by steric hindrance in a molecular‐weight‐dependent fashion. Great differences were observed as a function of the PEG architecture, with diblock PEG‐dendritic copolymers benefiting from a positive entropic contribution (PEG folding), not seen in the dendritic‐PEG‐dendritic systems. The self‐inflicted steric stabilization of the PEGylated copolymers onto lectin clusters reveals the necessity of additional competitive experiments to fully assess the antiadhesive properties of PEG in biological environments.
Nanostructure‐Dependent Ratiometric NIR Fluorescence Enabled by Ordered Dye Aggregation
Authors: Charron Danielle M. , Chen Juan , Zheng Gang 
Published: February 2016

AbstractNanocarriers incorporating therapeutic and imaging agents within a single nanostructure are emerging tools for drug development and treatment planning. Additional information can be provided using activatable fluorescence that dynamically reports nanocarrier disruption and drug release. Dual‐wavelength activation encodes a unique fluorescence signal for each nanocarrier state, enabling use of ratiometric imaging to measure the proportion of intact and disrupted nanocarriers within tissues. Here we investigate dual‐wavelength activation using a single dye whose optical properties are intricately linked to the nanocarrier structure. Natural bacteriochlorophyll incorporated within a compact lipoprotein nanocarrier forms ordered dye aggregates with red‐shifted fluorescence emission from 765 nm to 825 nm. We demonstrate that bacteriochlorophyll‐ordered aggregation is a feasible strategy to distinguish intact and disrupted theranostic nanocarriers by ratiometric fluorescence imaging.
The Role of Resonant Vibrations in Electronic Energy Transfer
Authors: Malý Pavel , Somsen Oscar J. G. , Novoderezhkin Vladimir I. , Mančal Tomáš , van Grondelle Rienk 
Published: February 2016

AbstractNuclear vibrations play a prominent role in the spectroscopy and dynamics of electronic systems. As recent experimental and theoretical studies suggest, this may be even more so when vibrational frequencies are resonant with transitions between the electronic states. Herein, a vibronic multilevel Redfield model is reported for excitonically coupled electronic two‐level systems with a few explicitly included vibrational modes and interacting with a phonon bath. With numerical simulations the effects of the quantized vibrations on the dynamics of energy transfer and coherence in a model dimer are illustrated. The resonance between the vibrational frequency and energy gap between the sites leads to a large delocalization of vibronic states, which then results in faster energy transfer and longer‐lived mixed coherences.
The Equally Important Role of Adenine Derivatives to That of Pyrimidine Derivatives in Near‐0 eV Electron‐Induced DNA Lesions
Authors: Wang Shoushan , Zhao Peiwen , Zhang Changzhe , Bu Yuxiang 
Published: February 2016

AbstractThe role of adenine (A) derivatives in DNA damage is scarcely studied due to the low electron affinity of base A. Experimental studies demonstrate that low‐energy electron (LEE) attachment to adenine derivatives complexed with amino acids induces barrier‐free proton transfer producing the neutral N7‐hydrogenated adenine radicals rather than conventional anionic species. To explore possible DNA lesions at the A sites under physiological conditions, probable bond ruptures in two models—N7‐hydrogenated 2′‐deoxyadenosine‐3′‐monophosphate (3′‐dA(N7H)MPH) and 2′‐deoxyadenosine‐5′‐monophosphate (5′‐dA(N7H)MPH), without and with LEE attachment—are studied by DFT. In the neutral cases, DNA backbone breakage and base release resulting from C3′−O3′ and N9−C1′ bond ruptures, respectively, by an intramolecular hydrogen‐transfer mechanism are impossible due to the ultrahigh activation energies. On LEE attachment, the respective C3′−O3′ and N9−C1′ bond ruptures in [3′‐dA(N7H)MPH]− and [5′‐dA(N7H)MPH]− anions via a pathway of intramolecular proton transfer (PT) from the C2′ site of 2′‐deoxyribose to the C8 atom of the base moiety become effective, and this indicates that substantial DNA backbone breaks and base release can occur at non‐3′‐end A sites and the 3′‐end A site of a single‐stranded DNA in the physiological environment, respectively. In particular, compared to the results of previous theoretical studies, not only are the electron affinities of 3′‐dA(N7H)MPH and 5′‐dA(N7H)MPH comparable to those of hydrogenated pyrimidine derivatives, but also the lowest energy requirements for the C3′−O3′ and N9‐glycosidic bond ruptures in [3′‐dA(N7H)MPH]− and [5′‐dA(N7H)MPH]− anions, respectively, are comparable to those for the C3′−O3′ and N1‐glycosidic bond cleavages in corresponding anionic hydrogenated pyrimidine derivatives. Thus, it can be concluded that the role of adenine derivatives in single‐stranded DNA damage is equally important to that of pyrimidine derivatives in an irradiated cellular environment.
Inhibition of AKT promotes FOXO3a-dependent apoptosis in prostate cancer
Authors: Das T P , Suman S , Alatassi H , Ankem M K , Damodaran C 
Published: February 2016

AbstractGrowth factor-induced activation of protein kinase-B (PKB), also known as AKT, induces pro-survival signaling and inhibits activation of pro-apoptotic signaling molecules including the Forkhead box O-3a (FOXO3a) transcription factor and caspase in transformed prostate cells in vitro. Earlier we reported that Withaferin-A (WA), a small herbal molecule, induces pro-apoptotic response-4 (Par-4) mediated apoptosis in castration-resistant prostate cancer (CRPC) cells. In the present study, we demonstrate that inhibition of AKT facilitates nuclear shuttling of FOXO3a where it regulates Par-4 transcription in CRPC cells. FOXO3a is upstream of Par-4 signaling, which is required for induction of apoptosis in CRPC cells. Promoter bashing studies and Ch-IP analysis confirm a direct interaction of FOXO3a and Par-4; a sequential deletion of FOXO3a-binding sites in the Par-4 promoter fails to induce Par-4 activation. To confirm these observations, we either overexpressed AKT or silenced FOXO3a activation in CRPC cells. Both methods inhibit Par-4 function and apoptosis is significantly compromised. In xenograft tumors derived from AKT-overexpressed CRPC cells, FOXO3a and Par-4 expression is downregulated, leading to aggressive tumor growth. Oral administration of WA to mice with xenograft tumors restores FOXO3a-mediated Par-4 functions and results in inhibited tumor growth. Finally, an inverse correlation of nuclear localization of AKT expression corresponds to cytoplasmic Par-4 localization in human prostate tissue array. Our studies suggest that Par-4 is one of the key transcriptional targets of FOXO3a, and Par-4 activation is required for induction of apoptosis in CRPC cells. Activation of FOXO3a appears to be an attractive target for the treatment of CRPC and molecules such as WA can be explored further for the treatment of CRPC.
Universal structures of normal and pathological heart rate variability
Authors: Gañán-Calvo Alfonso M. , Fajardo-López Juan 
Published: February 2016

AbstractThe circulatory system of living organisms is an autonomous mechanical system softly tuned with the respiratory system and both developed by evolution as a response to the complex oxygen demand patterns associated with motion. Circulatory health is rooted in adaptability, which entails an inherent variability. Here, we show that a generalized N-dimensional normalized graph representing heart rate variability reveals two universal arrhythmic patterns as specific signatures of health one reflects cardiac adaptability and the other the cardiac-respiratory rate tuning. In addition, we identify at least three universal arrhythmic profiles whose presences raise in proportional detriment of the two healthy ones in pathological conditions (myocardial infarction; heart failure; and recovery from sudden death). The presence of the identified universal arrhythmic structures together with the position of the centre of mass of the heart rate variability graph provide a unique quantitative assessment of the health-pathology gradient.
In a demanding task, three-handed manipulation is preferred to two-handed manipulation
Authors: Abdi Elahe , Burdet Etienne , Bouri Mohamed , Himidan Sharifa , Bleuler Hannes 
Published: February 2016

AbstractEquipped with a third hand under their direct control, surgeons may be able to perform certain surgical interventions alone; this would reduce the need for a human assistant and related coordination difficulties. However, does human performance improve with three hands compared to two hands? To evaluate this possibility, we carried out a behavioural study on the performance of naive adults catching objects with three virtual hands controlled by their two hands and right foot. The subjects could successfully control the virtual hands in a few trials. With this control strategy, the workspace of the hands was inversely correlated with the task velocity. The comparison of performance between the three and two hands control revealed no significant difference of success in catching falling objects and in average effort during the tasks. Subjects preferred the three handed control strategy, found it easier, with less physical and mental burden. Although the coordination of the foot with the natural hands increased trial after trial, about two minutes of practice was not sufficient to develop a sense of ownership towards the third arm.
Diffusion and self-assembly of C60 molecules on monolayer graphyne sheets
Authors: Ozmaian Masoumeh , Fathizadeh Arman , Jalalvand Morteza , Ejtehadi Mohammad Reza , Allaei S. Mehdi Vaez 
Published: February 2016

AbstractThe motion of a fullerene (C60) on 5 different types of graphyne is studied by all-atom molecular dynamics simulations and compared with former studies on the motion of C60 on graphene. The motion shows a diffusive behavior which consists of either a continuous motion or discrete movements between trapping sites depending on the type of the graphyne sheet. For graphyne-4 and graphyne-5, fullerenes could detach from the surface of the graphyne sheet at room temperature which was not reported for similar cases on graphene sheets. Collective motion of a group of fullerenes interacting with a graphyne studied and it is shown that fullerenes exhibit stable assemblies. Depending on the type of graphyne, these assemblies can have either single or double layers. The mobility of the assembled structures is also dependent on the type of the graphyne sheet. The observed properties of the motion suggests novel applications for the complexes of fullerene and monolayer graphynes.
Cyclodextrin-Based Metal-Organic Nanotube as Fluorescent Probe for Selective Turn-On Detection of Hydrogen Sulfide in Living Cells Based on H2S-Involved Coordination Mechanism
Authors: Xin Xuelian , Wang Jingxin , Gong Chuanfang , Xu Hai , Wang Rongming , Ji Shijie , Dong Hanxiao , Meng Qingguo , Zhang Liangliang , Dai Fangna , Sun Daofeng 
Published: February 2016

AbstractHydrogen sulfide (H2S) has been considered as the third biologically gaseous messenger (gasotransmitter) after nitric oxide (NO) and carbon monoxide (CO). Fluorescent detection of H2S in living cells is very important to human health because it has been found that the abnormal levels of H2S in human body can cause Alzheimer’s disease, cancers and diabetes. Herein, we develop a cyclodextrin-based metal-organic nanotube, CD-MONT-2, possessing a {Pb14} metallamacrocycle for efficient detection of H2S. CD-MONT-2′ (the guest-free form of CD-MONT-2) exhibits turn-on detection of H2S with high selectivity and moderate sensitivity when the material was dissolved in DMSO solution. Significantly, CD-MONT-2′ can act as a fluorescent turn-on probe for highly selective detection of H2S in living cells. The sensing mechanism in the present work is based on the coordination of H2S as the auxochromic group to the central Pb(II) ion to enhance the fluorescence intensity, which is studied for the first time.
Detection of substrate-dependent conformational changes in the P450 fold by nuclear magnetic resonance
Authors: Colthart Allison M. , Tietz Drew R. , Ni Yuhua , Friedman Jessica L. , Dang Marina , Pochapsky Thomas C. 
Published: February 2016

AbstractCytochrome P450 monooxygenases typically catalyze the insertion of one atom of oxygen from O2 into unactivated carbon-hydrogen and carbon-carbon bonds, with concomitant reduction of the other oxygen atom to H2O by NAD(P)H. Comparison of the average structures of the camphor hydroxylase cytochrome P450cam (CYP101) obtained from residual dipolar coupling (RDC)-restrained molecular dynamics (MD) in the presence and absence of substrate camphor shows structural displacements resulting from the essential collapse of the active site upon substrate removal. This collapse has conformational consequences that extend across the protein structure, none of which were observed in analogous crystallographic structures. Mutations were made to test the involvement of the observed conformational changes in substrate binding and recognition. All of the mutations performed based upon the NMR-detected perturbations, even those remote from the active site, resulted in modified substrate selectivity, enzyme efficiency and/or haem iron spin state. The results demonstrate that solution NMR can provide insights into enzyme structure-function relationships that are difficult to obtain by other methods.
Molecular Form Differences Between Prostate-Specific Antigen (PSA) Standards Create Quantitative Discordances in PSA ELISA Measurements
Authors: McJimpsey Erica L. 
Published: February 2016

AbstractThe prostate-specific antigen (PSA) assays currently employed for the detection of prostate cancer (PCa) lack the specificity needed to differentiate PCa from benign prostatic hyperplasia and have high false positive rates. The PSA calibrants used to create calibration curves in these assays are typically purified from seminal plasma and contain many molecular forms (intact PSA and cleaved subforms). The purpose of this study was to determine if the composition of the PSA molecular forms found in these PSA standards contribute to the lack of PSA test reliability. To this end, seminal plasma purified PSA standards from different commercial sources were investigated by western blot (WB) and in multiple research grade PSA ELISAs. The WB results revealed that all of the PSA standards contained different mass concentrations of intact and cleaved molecular forms. Increased mass concentrations of intact PSA yielded higher immunoassay absorbance values, even between lots from the same manufacturer. Standardization of seminal plasma derived PSA calibrant molecular form mass concentrations and purification methods will assist in closing the gaps in PCa testing measurements that require the use of PSA values, such as the % free PSA and Prostate Health Index by increasing the accuracy of the calibration curves.
Influence of Particle Size Distribution on the Performance of Ionic Liquid-based Electrochemical Double Layer Capacitors
Authors: Rennie Anthony J. R. , Martins Vitor L. , Smith Rachel M. , Hall Peter J. 
Published: February 2016

AbstractElectrochemical double layer capacitors (EDLCs) employing ionic liquid electrolytes are the subject of much research as they promise increased operating potentials, and hence energy densities, when compared with currently available devices. Herein we report on the influence of the particle size distribution of activated carbon material on the performance of ionic liquid based EDLCs. Mesoporous activated carbon was ball-milled for increasing durations and the resultant powders characterized physically (using laser diffraction, nitrogen sorption and SEM) and investigated electrochemically in the form of composite EDLC electrodes. A bi-modal particle size distribution was found for all materials demonstrating an increasing fraction of smaller particles with increased milling duration. In general, cell capacitance decreased with increased milling duration over a wide range of rates using CV and galvanostatic cycling. Reduced coulombic efficiency is observed at low rates (<25 mVs−1) and the efficiency decreases as the volume fraction of the smaller particles increases. Efficiency loss was attributed to side reactions, particularly electrolyte decomposition, arising from interactions with the smaller particles. The effect of reduced efficiency is confirmed by cycling for over 15,000 cycles, which has the important implication that diminished performance and reduced cycle life is caused by the presence of submicron-sized particles.
Life History Diversity in Klamath River Steelhead
Authors: Hodge Brian W. , Wilzbach Margaret A. , Duffy Walter G. , Quiñones Rebecca M. , Hobbs James A. 
Published: February 2016

AbstractOncorhynchus mykiss exhibits a vast array of life histories, which increases its likelihood of persistence by spreading risk of extirpation among different pathways. The Klamath River basin (California–Oregon) provides a particularly interesting backdrop for the study of life history diversity in O. mykiss, in part because the river is slated for a historic and potentially influential dam removal and habitat recolonization project. We used scale and otolith strontium isotope (87Sr/86Sr) analyses to characterize life history diversity in wild O. mykiss from the lower Klamath River basin. We also determined maternal origin (anadromous or nonanadromous) and migratory history (anadromous or nonanadromous) of O. mykiss and compared length and fecundity at age between anadromous (steelhead) and nonanadromous (Rainbow Trout) phenotypes of O. mykiss. We identified a total of 38 life history categories at maturity, which differed in duration of freshwater and ocean rearing, age at maturation, and incidence of repeat spawning. Approximately 10% of adult fish sampled were nonanadromous. Rainbow Trout generally grew faster in freshwater than juvenile steelhead; however, ocean growth afforded adult steelhead greater length and fecundity than adult Rainbow Trout. Although 75% of individuals followed the migratory path of their mother, steelhead produced nonanadromous progeny and Rainbow Trout produced anadromous progeny. Overall, we observed a highly diverse array of life histories among Klamath River O. mykiss. While this diversity should increase population resilience, recent declines in the abundance of Klamath River steelhead suggest that life history diversity alone is not sufficient to stabilize a population. Our finding that steelhead and Rainbow Trout give rise to progeny of the alternate form (1) suggests that dam removal might lead to a facultatively anadromous O. mykiss population in the upper basin and (2) raises the question of whether both forms of O. mykiss in the Klamath River should be managed under the same strategy.Received June 20, 2015; accepted October 16, 2015
Climate change predicted to lengthen transatlantic travel times
Authors: Simpson Isla R 
Published: February 2016

Abstract
Among the many consequences of rising atmospheric greenhouse gas concentrations, is a change to the medium through which planes fly. An emerging area of research is the impact that these changes may have on the airline industry, with studies addressing aspects ranging from the impact of rising temperatures on aeroplane weight restrictions (Coffel and Horton 2015 Wea. Climate Soc.

7 94–102) to the impact of changing wind shears on the occurrence of clear air turbulence (Williams and Joshi 2014 Nat. Clim. Change

3 644–8). Now, a recent study by Paul Williams (2016 Environ. Res. Lett.

11 024008), assesses the impact that changing winds may have on the duration of transatlantic flights.
Repeatability of decision-making behaviour in male threespine stickleback Gasterosteus aculeatus: Effects of dummy vs. live stimuli
Authors: Dzieweczynski Teresa L. , Forrette Lindsay M. 
Published: February 2016

Abstract
Individuals select from a number of behaviours when responding to various situations and the decisions they make may affect their fitness. The costs and benefits of these responses vary among individuals causing them to differ even in identical situations. One example of this type of situation is when territorial males encounter both a male and female simultaneously, generating a trade-off that likely leads to individual differences due to differing costs of various actions among males. This situation commonly occurs in threespine stickleback, Gasterosteus aculeatus. However, for selection to act effectively, individuals must behave in a consistent manner and measuring repeatability can aid in understanding how selection may shape such trade-offs. Males of this species exhibit consistent individual differences in their response to dummy males and females but it is unknown if patterns are similar when feedback from the stimuli is present. To assess this, male threespine stickleback were tested with dummy and live male and female conspecifics, presented separately and simultaneously. While the same trends were found regardless of stimulus type, males were more aggressive towards the live conspecifics than to the dummies. Repeatability values were similar within a treatment regardless of whether live or dummy conspecifics were used, suggesting that individuals show the same level of consistency. This study adds to our understanding of consistent individual differences by demonstrating that feedback may not affect responses to conflicting stimuli and that male threespine stickleback respond in a consistent manner to both dummy and live stimuli.
Differences in hoarding behavior between captive and wild sympatric rodent species
Authors: Zhang Hongmao , Wang Yu 
Published: February 2016

Abstract
In hand reared birds and mammals, it is generally considered that the development of hoarding behavior is the result of an interaction between the development and maturation of the nervous system and learning from individual experience. However, few studies have been done on wild animals. We tested differences in hoarding behavior between captive reared and wild individuals of two sympatric small rodents, Korean field mice Apodemus peninsulae and Chinese white-bellied rats Niviventer confucianus. Our aim was to identify if lack of experience from the wild would result in poorly developed hoarding behavior. The Korean field mice perform scatterand larder-hoarding behaviors whereas Chinese white-bellied rats hoard food in larders only. Within outdoor enclosures we compared seed-hoarding behavior in reared juveniles (RJ, 40-50 d old, pregnant mothers were captured in the wild), wild juveniles (WJ, as young as the RJ) and wild adults (WA, over-winter animals). We found that a lack of experience from the wild had significant effects on seed-hoarding behavior for both species. The RJ-group removed and hoarded fewer seeds than the WJand WA-groups. The two latter groups hoarded seeds in a similar way. In the Korean filed mouse the RJ-group placed more seeds on the ground surface than other groups. These findings suggest that wild experience is important for the acquisition of an appropriate food-hoarding behavior (especially for scatter-hoarding) in these species.