bluuebunny/crossref_metadata_2025 huggingface dataset:
Clusters of Ammonium Cation—Hydrogen Bond versus σ‐Hole Bond
Authors: Grabowski Sławomir J.
Published: February 2014

MP2/6‐311++G(d,p) calculations were performed on the NH4+⋅⋅⋅(HCN)nand NH4+⋅⋅⋅(N2)nclusters (n=1–8), and interactions within them were analyzed. It was found that for molecules of N2and HCN, the N centers play the role of the Lewis bases, whereas the ammonium cation acts as the Lewis acid, as it is characterized by sites of positive electrostatic potential, that is, H atoms and the sites located at the N atom in the extension of the HN bonds. Hence, the coordination number for the ammonium cation is eight, and two types of interactions of this cation with the Lewis base centers are possible: NH⋅⋅⋅N hydrogen bonds and HN⋅⋅⋅N interactions that are classified as σ‐hole bonds. Redistribution of the electronic charge resulting from complexation of the ammonium cation was analyzed. On the one hand, the interactions are similar, as they lead to electronic charge transfer from the Lewis base (HCN or N2in this study) to NH4+. On the other hand, the hydrogen bond results in the accumulation of electronic charge on the N atom of the NH4+ion, whereas the σ‐hole bond results in the depletion of the electronic charge on this atom. Quantum theory of “atoms in molecules” and the natural bond orbital method were applied to deepen the understanding of the nature of the interactions analyzed. Density functional theory/natural energy decomposition analysis was used to analyze the interactions of the ammonium ion with various types of Lewis bases. Different correlations between the geometrical, energetic, and topological parameters were found and discussed.
Superior Pseudocapacitive Behavior of Confined Lignin Nanocrystals for Renewable Energy‐Storage Materials
Authors: Kim Sung‐Kon , Kim Yun Ki , Lee Hyunjoo , Lee Sang Bok , Park Ho Seok
Published: February 2014

Strong demand for high‐performance energy‐storage devices has currently motivated the development of emerging capacitive materials that can resolve their critical challenge (i.e., low energy density) and that are renewable and inexpensive energy‐storage materials from both environmental and economic viewpoints. Herein, the pseudocapacitive behavior of lignin nanocrystals confined on reduced graphene oxides (RGOs) used for renewable energy‐storage materials is demonstrated. The excellent capacitive characteristics of the renewable hybrid electrodes were achieved by synergizing the fast and reversible redox charge transfer of surface‐confined quinone and the interplay with electron‐conducting RGOs. Accordingly, pseudocapacitors with remarkable rate and cyclic performances (∼96 % retention after 3000 cycles) showed a maximum capacitance of 432 F g−1, which was close to the theoretical capacitance of 482 F g−1 and sixfold higher than that of RGO (93 F g−1). The chemical strategy delineated herein paves the way to develop advanced renewable electrodes for energy‐storage applications and understand the redox chemistry of electroactive biomaterials.
The ALD‐MLD Growth of a ZnO‐Zincone Heterostructure
Authors: Choudhury Devika , Sarkar Shaibal K.
Published: February 2014

A mixed inorganic/organic zinc oxide/zincone multilayer film, using a combination of atomic layer deposition (ALD) and molecular layer deposition (MLD), is grown. A molecular fragment is deposited in each half reaction in the MLD technique, thus making it similar to, and compatible with, the ALD method of deposition. Zinc oxide inorganic layers are grown at a substrate temperature of 150°C with alternate surface‐saturating reactions of diethylzinc and water. Under similar growth condition, diethylzinc and hydroquinone are used to deposit an organic zincone layer that follows the MLD reaction mechanism. Deposition rates are obtained from an in‐situ quartz crystal microbalance (QCM) and verified using X‐ray reflectivity (XRR) measurements and scanning electron microscopy (SEM). Chemical constituents of the hybrid layers are confirmed from secondary ion mass spectroscopy (SIMS) and Fourier transform infrared (FTIR) spectroscopy. Selective etching of the organic layers results in the formation of zinc oxide nanosheets stacked together by van der Waals attraction balanced by Coulombic repulsion.
Factors influencing total carbon dioxide concentrations in plasma of thoroughbred and standardbred racehorses
Authors: Sutton Gordon J. , Cawley Adam , Murphy Cary , Lau Marcus L. , Hibbert D. Brynn
Published: February 2014

Horse racing authorities impose a limit on the concentration of plasma ‘total carbon dioxide’ (TCO2), typically 36 mM with action taken above 37 mM, as measured by an electrochemical gas analyzer. It is of interest to understand the distribution of TCO2 in a ‘normal’ population of racehorses and determine probabilities of members of this population exceeding these current regulatory and action limits. TCO2 levels in equine plasma samples have been modelled for 12 months (2011–2012) of thoroughbred (3076 measurements) and standardbred (3788 measurements) data in Australia. The two populations have a common seasonal pattern, while the non‐seasonal distributions differ. A single Gaussian distribution about the seasonal pattern explains the thoroughbred data, but there is evidence for a second Gaussian component for the standardbred horses. A Gaussian mixture model for standardbred horses gave a main component that matched the thoroughbred distribution, which was centred about 30.2 mM, and a smaller (about 20 % of the total density) Gaussian centred at 32.3 mM. The existence of a second, higher‐meaned population of standardbred horses points to increased use of alkalinizing salts among a minority of trainers, whom still, however, maintain mostly legal levels of TCO2. Identification of this group can be used to direct intelligence‐based testing with a view to limiting use of these products. Probabilities of exceeding limits are affected by seasonality, but the current rules remain conservative. Copyright © 2014 John Wiley & Sons, Ltd.
The minus‐end actin capping protein, UNC‐94/tropomodulin, regulates development of the Caenorhabditis elegans intestine
Authors: Cox‐Paulson Elisabeth , Cannataro Vincent , Gallagher Thomas , Hoffman Corey , Mantione Gary , Mcintosh Matthew , Silva Malan , Vissichelli Nicole , Walker Rachel , Simske Jeffrey , Ono Shoichiro , Hoops Harold
Published: February 2014

Background: Tropomodulins are actin‐capping proteins that regulate the stability of the slow‐growing, minus‐ends of actin filaments. The C. elegans tropomodulin homolog, UNC‐94, has sequence and functional similarity to vertebrate tropomodulins. We investigated the role of UNC‐94 in C. elegans intestinal morphogenesis. Results: In the embryonic C. elegans intestine, UNC‐94 localizes to the terminal web, an actin‐ and intermediate filament‐rich structure that underlies the apical membrane. Loss of UNC‐94 function results in areas of flattened intestinal lumen. In worms homozygous for the strong loss‐of‐function allele, unc‐94(tm724), the terminal web is thinner and the amount of F‐actin is reduced, pointing to a role for UNC‐94 in regulating the structure of the terminal web. The non‐muscle myosin, NMY‐1, also localizes to the terminal web, and we present evidence that increasing actomyosin contractility by depleting the myosin phosphatase regulatory subunit, mel‐11, can rescue the flattened lumen phenotype of unc‐94 mutants. Conclusions: The data support a model in which minus‐end actin capping by UNC‐94 promotes proper F‐actin structure and contraction in the terminal web, yielding proper shape of the intestinal lumen. This establishes a new role for a tropomodulin in regulating lumen shape during tubulogenesis. Developmental Dynamics 243:753–764, 2014. © 2014 Wiley Periodicals, Inc.
Adaptive latitudinal variation in Common Blackbird Turdus merula nest characteristics
Authors: Mainwaring Mark C. , Deeming D. Charles , Jones Chris I. , Hartley Ian R.
Published: February 2014

Nest construction is taxonomically widespread, yet our understanding of adaptive intraspecific variation in nest design remains poor. Nest characteristics are expected to vary adaptively in response to predictable variation in spring temperatures over large spatial scales, yet such variation in nest design remains largely overlooked, particularly amongst open‐cup‐nesting birds. Here, we systematically examined the effects of latitudinal variation in spring temperatures and precipitation on the morphology, volume, composition, and insulatory properties of open‐cup‐nesting Common Blackbirds’ Turdus merula nests to test the hypothesis that birds living in cooler environments at more northerly latitudes would build better insulated nests than conspecifics living in warmer environments at more southerly latitudes. As spring temperatures increased with decreasing latitude, the external diameter of nests decreased. However, as nest wall thickness also decreased, there was no variation in the diameter of the internal nest cups. Only the mass of dry grasses within nests decreased with warmer temperatures at lower latitudes. The insulatory properties of nests declined with warmer temperatures at lower latitudes and nests containing greater amounts of dry grasses had higher insulatory properties. The insulatory properties of nests decreased with warmer temperatures at lower latitudes, via changes in morphology (wall thickness) and composition (dry grasses). Meanwhile, spring precipitation did not vary with latitude, and none of the nest characteristics varied with spring precipitation. This suggests that Common Blackbirds nesting at higher latitudes were building nests with thicker walls in order to counteract the cooler temperatures. We have provided evidence that the nest construction behavior of open‐cup‐nesting birds systematically varies in response to large‐scale spatial variation in spring temperatures.
Does seasonality drive spatial patterns in demography? Variation in survival in African reed warblersAcrocephalus baeticatusacross southern Africa does not reflect global patterns
Authors: Jansen Dorine Y.M. , Abadi Fitsum , Harebottle Doug , Altwegg Res
Published: February 2014

Among birds, northern temperate species generally have larger clutches, shorter development periods and lower adult survival than similarly‐sized southern and tropical species. Even though this global pattern is well accepted, the driving mechanism is still not fully understood. The main theories are founded on the differing environmental seasonality of these zones (higher seasonality in the North). These patterns arise in cross‐species comparisons, but we hypothesized that the same patterns should arise among populations within a species if different types of seasonality select for different life histories. Few studies have examined this. We estimated survival of an azonal habitat specialist, the African reed warbler, across the environmentally diverse African subcontinent, and related survival to latitude and to the seasonality of the different environments of their breeding habitats. Data (1998–2010) collected through a public ringing scheme were analyzed with hierarchical capture‐mark‐recapture models to determine resident adult survival and its spatial variance across sixteen vegetation units spread across four biomes. The models were defined as state‐space multi‐state models to account for transience and implemented in a Bayesian framework. We did not find a latitudinal trend in survival or a clear link between seasonality and survival. Spatial variation in survival was substantial across the sixteen sites (spatial standard deviation of the logit mean survival: 0.70, 95% credible interval (CRI): 0.33–1.27). Mean site survival ranged from 0.49 (95% CRI: 0.18–0.80) to 0.83 (95% CRI: 0.62–0.97) with an overall mean of 0.67 (95% CRI: 0.47–0.85). A hierarchical modeling approach enabled us to estimate spatial variation in survival of the African reed warbler across the African subcontinent from sparse data. Although we could not confirm the global pattern of higher survival in less seasonal environments, our findings from a poorly studied region contribute to the study of life‐history strategies.
Endemicity and evolutionary value: a study of Chilean endemic vascular plant genera
Authors: Scherson Rosa A. , Albornoz Abraham A. , Moreira‐Muñoz Andrés S. , Urbina‐Casanova Rafael
Published: February 2014

This study uses phylogeny‐based measures of evolutionary potential (phylogenetic diversity and community structure) to evaluate the evolutionary value of vascular plant genera endemic to Chile. Endemicity is regarded as a very important consideration for conservation purposes. Taxa that are endemic to a single country are valuable conservation targets, as their protection depends upon a single government policy. This is especially relevant in developing countries in which conservation is not always a high resource allocation priority. Phylogeny‐based measures of evolutionary potential such as phylogenetic diversity (PD) have been regarded as meaningful measures of the “value” of taxa and ecosystems, as they are able to account for the attributes that could allow taxa to recover from environmental changes. Chile is an area of remarkable endemism, harboring a flora that shows the highest number of endemic genera in South America. We studied PD and community structure of this flora using a previously available supertree at the genus level, to which we added DNA sequences of 53 genera endemic to Chile. Using discrepancy values and a null model approach, we decoupled PD from taxon richness, in order to compare their geographic distribution over a one‐degree grid. An interesting pattern was observed in which areas to the southwest appear to harbor more PD than expected by their generic richness than those areas to the north of the country. In addition, some southern areas showed more PD than expected by chance, as calculated with the null model approach. Geological history as documented by the study of ancient floras as well as glacial refuges in the coastal range of southern Chile during the quaternary seem to be consistent with the observed pattern, highlighting the importance of this area for conservation purposes.
A perspective on re‐evaluating digoxin's role in the current management of patients with chronic systolic heart failure: targeting serum concentration to reduce hospitalization and improve safety profile
Authors: Adams Kirkwood F. , Ghali Jalal K. , Herbert Patterson J. , Stough Wendy Gattis , Butler Javed , Bauman Jerry L. , Ventura Hector O. , Sabbah Hani , Mackowiak John I. , van Veldhuisen Dirk J.
Published: February 2014

Digoxin improves exercise tolerance and reduces hospitalizations in patients with systolic heart failure, but its use has declined progressively for the past two decades. The Digitalis Investigation Group trial showed that digoxin reduced hospitalizations but had a neutral effect on total mortality. There was evidence that mortality caused by worsening heart failure was less, but there was also a signal suggesting an increase in other cardiac (presumed arrhythmic) death. Use of digoxin has declined substantially and recent guideline recommendations have significantly de‐emphasized the importance of this drug in the management of heart failure. Two developments suggest that re‐evaluation of the contemporary role of digoxin in the management of heart failure with reduced ejection fraction is warranted. First, heart failure remains progressive, characterized by chronic debility, exercise intolerance, and frequent and costly hospitalizations, despite evidence‐based drug and device therapies that prolong survival. Health economics have made reducing hospitalizations in patients with heart failure a major priority. Second, a strong association has emerged between serum concentration and the safety and efficacy of digoxin, which indicates a change in our approach to dosing this agent is needed. Experimental and clinical results suggest that optimizing therapeutic benefit and avoiding harm means dosing to achieve low serum digoxin concentrations (0.5–0.9 ng/mL). Digoxin is an inexpensive agent and the totality of evidence indicates that it reduces hospitalizations and improves symptoms safely when dosed to achieve low serum concentrations. These findings suggest digoxin should have a more prominent therapeutic role in patients with heart failure and reduced ejection fraction.
Donor and host B cell‐derived IL‐10 contributes to suppression of graft‐versus‐host disease
Authors: Weber Michael , Stein Pamela , Prüfer Steve , Rudolph Berenice , Kreft Andreas , Schmitt Edgar , Bopp Tobias , Roers Axel , Schild Hansjörg , Fillatreau Simon , Radsak Markus P.
Published: February 2014

Graft‐versus‐host disease (GvHD) is a frequent life‐threatening complication following allogeneic HSC transplantation (HSCT). IL‐10 is a regulatory cytokine with important roles during GvHD, yet its relevant sources, and mode of action, remain incompletely defined in this disease. Using IL‐10‐deficient donor or host mice (BALB/c or C57BL/6, respectively) in a MHC‐mismatched model for acute GvHD, we found a strongly aggravated course of the disease with increased mortality when either donor or host cells could not produce this cytokine. A lack of IL‐10 resulted in increased allogeneic T‐cell responses and enhanced activation of host DCs in spleen and MLNs. Remarkably, IL‐10 was prominently produced by host‐ and donor‐derived CD5intCD1dintTIM‐1int B cells in this disease, and consistent with this, allogeneic HSCT resulted in exacerbated GvHD when mice lacking IL‐10 expression in B cells were used as donor or host, compared with controls. Taken together, this study demonstrates that host and donor B cell‐derived IL‐10 provides a unique mechanism of suppression of acute GvHD, and suggests that DCs are the targets of this B cell‐mediated suppressive effect. These findings open novel therapeutic possibilities based on the use of B cells to increase the feasibility of allogeneic HSCT.
Electron Transfer from Excited [Ir(2‐phenylpyridyl)3] through a Coexisting Electron Relay in Zeolite
Authors: Xu Chen , Mochizuki Dai , Maitani Masato M. , Wada Yuji
Published: February 2014

Photoinduced electron transfer was investigated between an ortho‐metalated IrIII complex encapsulated in the supercage of faujasite zeolite dispersed in solution and viologen derivatives dissolved in the solution. The electron‐transfer rate across the zeolite solution interface was 310 times slower than that between the free molecules in solution. To facilitate electron transfer, 1,1′‐ethylene‐2,2′‐bipyridyldiylium (diquat = 2DQ2+) was introduced as an electron relay into the zeolite by ion exchange. When triethanolamine (TEOA) was added as a sacrificial electron donor into the dispersion solution, the 2DQ2+ in the supercages was reduced to 2DQ·+ radical cation under light irradiation, which can be explained as the electron transfer from the excited state of the IrIII complex to 2DQ2+, and the regeneration of the complex through the reduction of the resulting oxidized complex by the electron donor TEOA in the solution through the zeolite solution interface. An electron is transferred through the zeolite framework from the 2DQ·+ radical cation formed in the supercage to propyl viologen sulfonate in the solution. This system demonstrates controllability of the electron transfer by solid host materials such as zeolites.
Planar Binuclear Phthalocyanine‐Containing Sandwich‐Type Rare‐Earth Complexes: Synthesis, Spectroscopy, Electrochemistry, and NLO Properties
Authors: Huang Chunhua , Wang Kang , Sun Junshang , Jiang Jianzhuang
Published: February 2014

The mixed cyclic tetramerization of 4,5‐bis(hexylthio)phthalonitrile and bis(diiminoisoindoline) with [M(acac)3]·nH2O (M = Pr, Eu, Lu) as template in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in n‐pentanol at reflux has provided binuclear phthalocyanine‐containing sandwich‐type rare‐earth complexes [{Pc(SC6H13)8}M{BiPc(SC6H13)12}M(SC6H13)8] (M = Pr, Eu, Lu; 1–3). These new binuclear phthalocyanine‐containing sandwich compounds have been characterized by a series of spectroscopic methods including mass spectrometry and 1H NMR, electronic absorption, and IR spectroscopy in addition to elemental analysis. Their electrochemical data have also been obtained by cyclic voltammetry. In addition, the third‐order nonlinear optical properties of [{Pc(SC6H13)8}Pr{BiPc(SC6H13)12}Pr(SC6H13)8] (1) and [Pr{Pc(SC6H13)8}2] in toluene solution were studied comparatively by using the Z‐scan technique; effective imaginary third‐order molecular hyperpolarizabilities of 1.86 × 10–11 and 1.56 × 10–11 esu, respectively, were obtained, which indicates their potential application in the optical‐limiting field.
Copper‐Mediated 1,4‐Diamination of 1,3‐Butadienes
Authors: Martínez Claudio , Martínez Luis , Kirsch Jonathan , Escudero‐Adán Eduardo C. , Martin Eddy , Muñiz Kilian
Published: February 2014

A copper(II)‐mediated diamination of 1,3‐butadienes is reported. The reaction employs an inorganic base, copper dibromide as a reagent, and saccharin as the nitrogen source. The diamination proceeds for a series of 1,3‐butadienes under relatively mild conditions with complete selectivity in favor of the 1,4‐oxidation products.
Total Synthesis and Structural Revision of (–)‐Protubonine A and (–)‐Protubonine B
Authors: Lorenzo Paula , Álvarez Rosana , de Lera Ángel R.
Published: February 2014

The proposed structures of (–)‐protubonine A and (–)‐protubonine B, which are pyrrolidinoindoline diketopiperazine alkaloids that were isolated from the marine‐derived fungus Aspergillus sp. SF‐5044, have been synthesized and correspond to diastereomers of the natural isolates. The total syntheses, herein, established the stereostructures of the alkaloids as the C‐11 epimers of the purported structures.
Palladium‐Catalyzed C–H Acylation of Arenes Using Thioethers as Directing Groups
Authors: Xu Bo , Liu Wei , Kuang Chunxiang
Published: February 2014

A highly efficient protocol for regioselective synthesis of diaryl ketones by palladium‐catalyzed direct acylation of arenes using thioethers as directing groups is reported. The possible pathway of direct acylation between thioethers and α‐oxocarboxylic acids is discussed.
Supercapacitors Based on Flexible Substrates: An Overview
Authors: Dubal Deepak P. , Kim Jong Guk , Kim Youngmin , Holze Rudolf , Lokhande Chandrakant D. , Kim Won Bae
Published: February 2014

Recently our modern society is demanding flexible, low‐cost, and lightweight electrochemical energy storage systems, which are very important in variety of applications ranging from portable consumer electronics to large industrial‐scale power and energy management. Among different energy storage systems, flexible supercapacitors have been considered as one of the most promising candidates due to their significant merits such as high power density along with the unique properties of being flexible, lightweight, shape versatile, and eco‐friendly in comparison to other energy storage systems. In this regard, this review article describes the principles of supercapacitors and the recent research progress on flexible supercapacitor electrodes, for which metal substrates, carbon‐based paper, conventional paper, textiles, sponges, and cables are used as substrates to fabricate high‐performance flexible supercapacitors. Finally, the future challenges and perspectives for the development of flexible supercapacitors based on bendable substrates and their applications are discussed.
Multistep weighted essentially non‐oscillatory scheme
Authors: Shen Yiqing , Liu Li , Yang Yan
Published: February 2014

A fifth‐order accurate multistep weighted essentially non‐oscillatory (WENO) scheme is constructed in this paper. Different from the traditional WENO schemes, which are designed to have (2r−1)th order accuracy in the smooth regions directly from r candidate stencils, the new scheme is constructed through (r−1) weighting steps. In each step, only two neighboring stencils are used to construct the intermediate fluxes (or the final flux), which are only one order higher than the fluxes obtained from the previous step. Henrick's mapping function is used in each step to satisfy the sufficient condition of fifth‐order convergence for a fifth‐order WENO scheme; hence, the new scheme is fifth‐order accurate in smooth regions. The distinctive advantage of the new scheme is that it can improve the accuracy by one order higher than the traditional WENO schemes at transition points (connecting a smooth region and a discontinuity point); and hence, it improves the accuracy in the regions near discontinuities. Numerical examples show that the new scheme is robust and is less dissipative than the traditional fifth‐order WENO schemes. Copyright © 2014 John Wiley & Sons, Ltd.
Modeling and Parametric Study of a Single Solid Oxide Fuel Cell by Finite Element Method
Authors: Daneshvar K. , Dotelli G. , Cristiani C. , Pelosato R. , Santarelli M.
Published: February 2014

A 2D isothermal axisymmetric model of an anode‐supported solid oxide fuel cell has been developed. The model, which is based on finite element approach, comprises electronic and ionic charge balance, Butler–Volmer charge transfer kinetic, flow distribution and gas phase mass balance in both channels and porous electrodes. The model has been validated using available experimental data coming from a single anode‐supported cell comprising Ni–YSZ/YSZ/LSM–YSZ as anode, electrolyte and cathode, respectively. Hydrogen and steam were used as fuel inlet and air as an oxidant. The validation has been carried out at 1 atm, 1,500 ml min–1 air flow rate and three different operating conditions of temperature and fuel flow rate: 1,073 K and 400 ml min–1, 1,073 K and 500 ml min–1, and 1,003 K and 400 ml min–1. The polarization and power density versus current density curves show a good agreement with the experimental data. A parametric analysis has been carried out to highlight which parameters have main effect on the overall cell performance as measured by polarization curve, especially focusing on the influence of two geometrical characteristics, temperature and some effective material properties.
Reversed hierarchy in the brain for general and specific cognitive abilities: A morphometric analysis
Authors: Román Francisco J. , Abad Francisco J. , Escorial Sergio , Burgaleta Miguel , Martínez Kenia , Álvarez‐Linera Juan , Quiroga María Ángeles , Karama Sherif , Haier Richard J. , Colom Roberto
Published: February 2014

Intelligence is composed of a set of cognitive abilities hierarchically organized. General and specific abilities capture distinguishable, but related, facets of the intelligence construct. Here, we analyze gray matter with three morphometric indices (volume, cortical surface area, and cortical thickness) at three levels of the intelligence hierarchy (tests, first‐order factors, and a higher‐order general factor, g). A group of one hundred and four healthy young adults completed a cognitive battery and underwent high‐resolution structural MRI. Latent scores were computed for the intelligence factors and tests were also analyzed. The key finding reveals substantial variability in gray matter correlates at the test level, which is substantially reduced for the first‐order and the higher‐order factors. This supports a reversed hierarchy in the brain with respect to cognitive abilities at different psychometric levels: the greater the generality, the smaller the number of relevant gray matter clusters accounting for individual differences in intelligent performance. Hum Brain Mapp 35:3805–3818, 2014. © 2014 Wiley Periodicals, Inc.
Repetition suppression of face‐selective evoked and induced EEG recorded from human cortex
Authors: Engell Andrew D. , McCarthy Gregory
Published: February 2014

In functional MRI studies, repetition suppression refers to the reduction of hemodynamic activation to repeated stimulus presentation. For example, the repeated presentation of a face reduces the hemodynamic response evoked by faces in the fusiform gyrus. The neural events that underlie repetition suppression are not well understood. Indeed, in contrast to the hemodynamic response, the face‐specific N200 recorded from subdural electrodes on the ventral occipitotemporal cortex, primarily along the fusiform gyrus, has been reported to be insensitive to face‐identity repetition. We have previously described a face‐specific broadband gamma (30–100 Hz) response at ventral face‐specific N200 sites that is functionally dissociable from the N200. In this study, we investigate whether gamma and other components of the electroencephalogram spectrum are affected by face‐identity repetition independently of the N200. Participants viewed sequentially presented identical faces. At sites on and around the fusiform gyrus, we found that face repetition modulated alpha (8–12 Hz), low‐gamma (30–60 Hz), and high‐gamma (60–100 Hz) synchrony, but not the N200. These findings provide evidence of a spatially co‐localized progression of face processing. Whereas the N200 reflects an initial obligatory response that is less sensitive to face‐identity repetition, the subsequent spectral fluctuations reflect more elaborative face processing and are thus sensitive to face novelty. It is notable that the observed modulations were different for different frequency bands. We observed repetition suppression of broadband gamma, but repetition enhancement of alpha synchrony. This difference is discussed with regard to an existing model of repetition suppression and behavioral repetition priming. Hum Brain Mapp 35:4155–4162, 2014. © 2014 Wiley Periodicals, Inc.
Spatial patterns of genome‐wide expression profiles reflect anatomic and fiber connectivity architecture of healthy human brain
Authors: Goel Pragya , Kuceyeski Amy , LoCastro Eve , Raj Ashish
Published: February 2014

Unraveling the relationship between molecular signatures in the brain and their functional, architectonic, and anatomic correlates is an important neuroscientific goal. It is still not well understood whether the diversity demonstrated by histological studies in the human brain is reflected in the spatial patterning of whole brain transcriptional profiles. Using genome‐wide maps of transcriptional distribution of the human brain by the Allen Brain Institute, we test the hypothesis that gene expression profiles are specific to anatomically described brain regions. In this work, we demonstrate that this is indeed the case by showing that gene similarity clusters appear to respect conventional basal‐cortical and caudal‐rostral gradients. To fully investigate the causes of this observed spatial clustering, we test a connectionist hypothesis that states that the spatial patterning of gene expression in the brain is simply reflective of the fiber tract connectivity between brain regions. We find that although gene expression and structural connectivity are not determined by each other, they do influence each other with a high statistical significance. This implies that spatial diversity of gene expressions is a result of mainly location‐specific features but is influenced by neuronal connectivity, such that like cellular species preferentially connects with like cells. Hum Brain Mapp 35:4204–4218, 2014. © 2014 Wiley Periodicals, Inc.
Employment pathways and work‐related issues in head and neck cancer survivors
Authors: Koch Robert , Wittekindt Claus , Altendorf–Hofmann Annelore , Singer Susanne , Guntinas–Lichius Orlando
Published: February 2014

Background

In this exploratory study, employment and psychological factors were investigated in head and neck cancer survivors with survivorship of ≥2 years.

Methods

Fifty‐five head and neck cancer survivors ≤60 years old completed a survey including subscales from the Functional Assessment of Cancer Therapy (FACT) instrument, the Miller Behavioral Style Scale, the General Perceived Self‐Efficacy Scale, the Patient Health Questionnaire‐9 (PHQ‐9), and the Hornheider–Fragebogen short version (HFB) measuring the need for psychological interventions. Exploratory analyses of associations to the employment status were performed.

Results

The rate of employed patients dropped from three‐fourths of patients before diagnosis to one‐third at an average of 66.8 months after diagnosis. Current unemployment was associated with harder physical work before cancer diagnosis, surgical treatment, and current risky alcohol consumption. Unemployed survivors reported decreased FACT functional and social well‐being and higher PHQ depression scores.

Conclusion

Psychosocial variables were significantly related to employment. Further research is needed to examine these relationships. © 2014 Wiley Periodicals, Inc. Head Neck 37: 585–593, 2015
Conjugated bile acids promote cholangiocarcinoma cell invasive growth through activation of sphingosine 1-phosphate receptor 2
Authors: Liu Runping , Zhao Renping , Zhou Xiqiao , Liang Xiuyin , Campbell Deanna J.W. , Zhang Xiaoxuan , Zhang Luyong , Shi Ruihua , Wang Guangji , Pandak William M. , Sirica Alphonse E. , Hylemon Phillip B. , Zhou Huiping
Published: February 2014

Cholangiocarcinoma (CCA) is an often fatal primary malignancy of the intra- and extrahepatic biliary tract that is commonly associated with chronic cholestasis and significantly elevated levels of primary and conjugated bile acids (CBAs), which are correlated with bile duct obstruction (BDO). BDO has also recently been shown to promote CCA progression. However, whereas there is increasing evidence linking chronic cholestasis and abnormal bile acid profiles to CCA development and progression, the specific mechanisms by which bile acids may be acting to promote cholangiocarcinogenesis and invasive biliary tumor growth have not been fully established. Recent studies have shown that CBAs, but not free bile acids, stimulate CCA cell growth, and that an imbalance in the ratio of free to CBAs may play an important role in the tumorigenesis of CCA. Also, CBAs are able to activate extracellular signal-regulated kinase (ERK)1/2- and phosphatidylinositol-3-kinase/protein kinase B (AKT)-signaling pathways through sphingosine 1-phosphate receptor 2 (S1PR2) in rodent hepatocytes. In the current study, we demonstrate S1PR2 to be highly expressed in rat and human CCA cells, as well as in human CCA tissues. We further show that CBAs activate the ERK1/2- and AKT-signaling pathways and significantly stimulate CCA cell growth and invasion in vitro. Taurocholate (TCA)-mediated CCA cell proliferation, migration, and invasion were significantly inhibited by JTE-013, a chemical antagonist of S1PR2, or by lentiviral short hairpin RNA silencing of S1PR2. In a novel organotypic rat CCA coculture model, TCA was further found to significantly increase the growth of CCA cell spheroidal/“duct-like” structures, which was blocked by treatment with JTE-013. Conclusion: Our collective data support the hypothesis that CBAs promote CCA cell-invasive growth through S1PR2. (Hepatology 2014;60:908–918)
Systemic protection through remote ischemic preconditioning is spread by platelet-dependent signaling in mice
Authors: Oberkofler Christian E. , Limani Perparim , Jang Jae-Hwi , Rickenbacher Andreas , Lehmann Kuno , Raptis Dimitri A. , Ungethuem Udo , Tian Yinghua , Grabliauskaite Kamile , Humar Rok , Graf Rolf , Humar Bostjan , Clavien Pierre-Alain
Published: February 2014

Remote ischemic preconditioning (RIPC), the repetitive transient mechanical obstruction of vessels at a limb remote to the operative site, is a novel strategy to mitigate distant organ injury associated with surgery. In the clinic, RIPC has demonstrated efficacy in protecting various organs against ischemia reperfusion (IR), but a common mechanism underlying the systemic protection has not been identified. Here, we reasoned that protection may rely on adaptive physiological reponses toward local stress, as is incurred through RIPC. Standardized mouse models of partial hepatic IR and of RIPC to the femoral vascular bundle were applied. The roles of platelets, peripheral serotonin, and circulating vascular endothelial growth factor (Vegf) were studied in thrombocytopenic mice, Tph1−
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mice, and through neutralizing antibodies, respectively. Models of interleukin-10 (Il10) and matrix metalloproteinase 8 (Mmp8) deficiency were used to assess downstream effectors of organ protection. The protection against hepatic IR through RIPC was dependent on platelet-derived serotonin. Downstream of serotonin, systemic protection was spread through up-regulation of circulating Vegf. Both RIPC and serotonin-Vegf induced differential gene expression in target organs, with Il10 and Mmp8 displaying consistent up-regulation across all organs investigated. Concerted inhibition of both molecules abolished the protective effects of RIPC. RIPC was able to mitigate pancreatitis, indicating that it can protect beyond ischemic insults. Conclusions: We have identified a platelet-serotonin-Vegf-Il10/Mmp8 axis that mediates the protective effects of RIPC. The systemic action, the conservation of RIPC effects among mice and humans, and the protection beyond ischemic insults suggest that the platelet-dependent axis has evolved as a preemptive response to local stress, priming the body against impending harm. (Hepatology 2014;60:1409–1417)
Infiltration and soil water dynamics in a tropical dry forest: it may be dry but definitely not arid
Authors: Farrick Kegan K. , Branfireun Brian A.
Published: February 2014

Studies of hydrological processes in tropical dry forests are less than 1% of published forest hydrology literature. The strong dry‐wet seasonality typical of the tropical dry forest ecoregion is similar to those that characterize semi‐arid regions. In semi‐arid systems, infiltration is often limited by low hydraulic conductivities (K) and extreme levels of soil water repellency, which when combined with high rainfall intensities, result in infiltration excess (Hortonian) overland flow (HOF) as a dominant runoff mechanism. Given that little is known about the surface runoff hydrology of tropical dry forests, we tested the hypothesis that our knowledge about controls on runoff in semi‐arid systems is transferrable to tropical dry forest hillslopes. Our results show that tropical dry forest soils do develop a strong water repellency during the dry season; however, this does not persist through the wet season. In our period of study, surface K ranged from 9 to 164 mm/h and was greater than the rainfall intensity for more than 75% of the rain events. In our period of study, rainfall intensities were generally low with more than half of the storm events falling between 0.2 and 4.2 mm/h. The low rainfall intensities, high K and lack of repellent surfaces during the wet season result in the percolation of >70% of the annual rainfall through the upper 30 cm of soil, indicating that subsurface flow, not HOF, is the primary runoff mechanism. These findings show that in spite of similar climate and vegetation regimes, hydrological knowledge from semi‐arid catchments is not transferrable to tropical dry forests. Copyright © 2014 John Wiley & Sons, Ltd.
Tumor heterogeneity and cancer stem cell paradigm: Updates in concept, controversies and clinical relevance
Authors: Singh Anup Kumar , Arya Rakesh Kumar , Maheshwari Shrankhla , Singh Akhilesh , Meena Sanjeev , Pandey Priyanka , Dormond Olivier , Datta Dipak
Published: February 2014

Although tumor heterogeneity is widely accepted, the existence of cancer stem cells (CSCs) and their proposed role in tumor maintenance has always been challenged and remains a matter of debate. Recently, a path‐breaking chapter was added to this saga when three independent groups reported the in vivo existence of CSCs in brain, skin and intestinal tumors using lineage‐tracing and thus strengthens the CSC concept; even though certain fundamental caveats are always associated with lineage‐tracing approach. In principle, the CSC hypothesis proposes that similar to normal stem cells, CSCs maintain self renewal and multilineage differentiation property and are found at the central echelon of cellular hierarchy present within tumors. However, these cells differ from their normal counterpart by maintaining their malignant potential, alteration of genomic integrity, epigenetic identity and the expression of specific surface protein profiles. As CSCs are highly resistant to chemotherapeutics, they are thought to be a crucial factor involved in tumor relapse and superficially appear as the ultimate therapeutic target. However, even that is not the end; further complication is attributed by reports of bidirectional regeneration mechanism for CSCs, one from their self‐renewal capability and another from the recently proposed concept of dynamic equilibrium between CSCs and non‐CSCs via their interconversion. This phenomenon has currently added a new layer of complexity in understanding the biology of tumor heterogeneity. In‐spite of its associated controversies, this area has rapidly emerged as the center of attention for researchers and clinicians, because of the conceptual framework it provides towards devising new therapies.
Rotifers as models for the biology of aging
Authors: Snell Terry W.
Published: February 2014

It has been two decades since 1993 when research on the biology of rotifer aging was last reviewed by Enesco. Much has transpired during this time as rotifer biologists have adapted to the “omics” revolution and incorporated these techniques into the experimental analysis of rotifers. Rotifers are amenable to many of these approaches and getting adequate quantities of DNA, RNA, and protein from rotifers is not difficult. Analysis of rotifer genomes, transcriptomes, and proteomes is rapidly yielding candidate genes that likely regulate a variety of features of rotifer biology. Parallel developments in aging biology have recognized the limitations of standard animal models like worms and flies and that comparative aging research has essentially ignored a large fraction of animal phylogeny in the lophotrochozoans. As experimentally tractable members of this group, rotifers have attracted interest as models of aging. In this paper, I review advances over the past 20 years in the biology of aging in rotifers, with emphasis on the unique contributions of rotifer models for understanding aging. The majority of experimental work has manipulated rotifer diet and followed changes in survival and reproductive dynamics like mean lifespan, maximum lifespan, reproductive lifespan, and mortality rate doubling time. The main dietary manipulation has been some form of caloric restriction, withholding food for some period or feeding continuously at low levels. There have been comparative studies of several rotifer species, with some species responding to caloric restriction with life extension, but others not, at least under the tested food regimens. Other aspects of diet are less explored, like nutritional properties of different algae species and their capacity to extend rotifer lifespan. Several descriptive studies have reported many genes involved in rotifer aging by comparing gene expression in young and old individuals. Classes of genes up or down‐regulated during aging have become prime targets for rotifer aging investigations. Alterations of gene expression by exposure to specific inhibitors or RNA interference (RNAi) knockdown will probably yield valuable insights into the cellular mechanisms of rotifer life extension. In this paper, I highlight major experimental contributions and indicate opportunities where I believe additional investigation is likely to be profitable.
Role of Fas and Treg Cells in Fracture Healing as Characterized in the Fas-Deficient (lpr) Mouse Model of Lupus
Authors: Al-Sebaei Maisa O , Daukss Dana M , Belkina Anna C , Kakar Sanjeev , Wigner Nathan A , Cusher Daniel , Graves Dana , Einhorn Thomas , Morgan Elise , Gerstenfeld Louis C
Published: February 2014

Previous studies showed that loss of tumor necrosis factor α (TNFα) signaling delayed fracture healing by delaying chondrocyte apoptosis and cartilage resorption. Mechanistic studies showed that TNFα induced Fas expression within chondrocytes; however, the degree to which chondrocyte apoptosis is mediated by TNFα alone or dependent on the induction of Fas is unclear. This question was addressed by assessing fracture healing in Fas-deficient B6.MRL/Faslpr/J mice. Loss of Fas delayed cartilage resorption but also lowered bone fraction in the calluses. The reduced bone fraction was related to elevated rates of coupled bone turnover in the B6.MRL/Faslpr/J calluses, as evidenced by higher osteoclast numbers and increased osteogenesis. Analysis of the apoptotic marker caspase 3 showed fewer positive chondrocytes and osteoclasts in calluses of B6.MRL/Faslpr/J mice. To determine if an active autoimmune state contributed to increased bone turnover, the levels of activated T cells and Treg cells were assessed. B6.MRL/Faslpr/J mice had elevated Treg cells in both spleens and bones of B6.MRL/Faslpr/J but decreased percentage of activated T cells in bone tissues. Fracture led to ∼30% to 60% systemic increase in Treg cells in both wild-type and B6.MRL/Faslpr/J bone tissues during the period of cartilage formation and resorption but either decreased (wild type) or left unchanged (B6.MRL/Faslpr/J) the numbers of activated T cells in bone. These results show that an active autoimmune state is inhibited during the period of cartilage resorption and suggest that iTreg cells play a functional role in this process. These data show that loss of Fas activity specifically in chondrocytes prolonged the life span of chondrocytes and that Fas synergized with TNFα signaling to mediate chondrocyte apoptosis. Conversely, loss of Fas systemically led to increased osteoclast numbers during later periods of fracture healing and increased osteogenesis. These findings suggest that retention of viable chondrocytes locally inhibits osteoclast activity or matrix proteolysis during cartilage resorption. © 2014 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.