bluuebunny/crossref_metadata_2025_split huggingface dataset:
Climate of origin affects tick (Ixodes ricinus) host‐seeking behavior in response to temperature: implications for resilience to climate change?
Authors: Gilbert Lucy , Aungier Jennifer , Tomkins Joseph L. 
Published: March 2014

AbstractClimate warming is changing distributions and phenologies of many organisms and may also impact on vectors of disease‐causing pathogens. In Europe, the tick Ixodes ricinus is the primary vector of medically important pathogens (e.g., Borrelia burgdorferi sensu lato, the causative agent of Lyme borreliosis). How might climate change affect I. ricinus host‐seeking behavior (questing)? We hypothesize that, in order to maximize survival, I. ricinus have adapted their questing in response to temperature in accordance with local climates. We predicted that ticks from cooler climates quest at cooler temperatures than those from warmer climates. This would suggest that I. ricinus can adapt and therefore have the potential to be resilient to climate change. I. ricinus were collected from a cline of climates using a latitudinal gradient (northeast Scotland, North Wales, South England, and central France). Under laboratory conditions, ticks were subjected to temperature increases of 1°C per day, from 6 to 15°C. The proportion of ticks questing was recorded five times per temperature (i.e., per day). The theoretical potential to quest was then estimated for each population over the year for future climate change projections. As predicted, more ticks from cooler climates quested at lower temperatures than did ticks from warmer climates. The proportion of ticks questing was strongly associated with key climate parameters from each location. Our projections, based on temperature alone, suggested that populations could advance their activity season by a month under climate change, which has implications for exposure periods of hosts to tick‐borne pathogens. Our findings suggest that I. ricinus have adapted their behavior in response to climate, implying some potential to adapt to climate change. Predictive models of I. ricinus dynamics and disease risk over continental scales would benefit from knowledge of these differences between populations.
Generation of memory B cells inside and outside germinal centers
Authors: Takemori Toshitada , Kaji Tomohiro , Takahashi Yoshimasa , Shimoda Michiko , Rajewsky Klaus 
Published: March 2014

Germinal centers (GCs) are generally considered to be the sole site of memory B‐cell generation. However, recent studies demonstrate that memory B cells can also develop in response to a T‐cell dependent (TD) antigen before the onset, and independently of, the GC reaction. These two classes of memory cells persist equally over long periods of time and attain functional maturation through distinct but related transcriptional programs. Although the development of both memory B‐cell types requires classical T‐cell help, the generation of GC‐dependent memory B cells requires TFH‐cell help, while the generation of GC‐independent memory cells does not. These findings led to the conclusion that B‐cell memory is generated along two fundamentally distinct cellular differentiation pathways. In this review, we focus on the GC‐independent pathway of memory B‐cell development, and discuss how the unique features of memory B cells are maintained in the GC‐independent pathway.
Genetic modifiers of cognitive maintenance among older adults
Authors: Yokoyama Jennifer S. , Evans Daniel S. , Coppola Giovanni , Kramer Joel H. , Tranah Gregory J. , Yaffe Kristine 
Published: March 2014

AbstractObjectiveIdentify genetic factors associated with cognitive maintenance in late life and assess their association with gray matter (GM) volume in brain networks affected in aging.MethodsWe conducted a genome‐wide association study of ∼2.4 M markers to identify modifiers of cognitive trajectories in Caucasian participants (N = 7,328) from two population‐based cohorts of non‐demented elderly. Standardized measures of global cognitive function (z‐scores) over 10 and 6 years were calculated among participants and mixed model regression was used to determine subject‐specific cognitive slopes. “Cognitive maintenance” was defined as a change in slope of ≥ 0 and was compared with all cognitive decliners (slope < 0). In an independent cohort of cognitively normal older Caucasians adults (N = 122), top association findings were then used to create genetic scores to assess whether carrying more cognitive maintenance alleles was associated with greater GM volume in specific brain networks using voxel‐based morphometry.ResultsThe most significant association was on chromosome 11 (rs7109806, P = 7.8 × 10−8) near RIC3. RIC3 modulates activity of α7 nicotinic acetylcholine receptors, which have been implicated in synaptic plasticity and beta‐amyloid binding. In the neuroimaging cohort, carrying more cognitive maintenance alleles was associated with greater volume in the right executive control network (RECN; PFWE = 0.01).ConclusionsThese findings suggest that there may be genetic loci that promote healthy cognitive aging and that they may do so by conferring robustness to GM in the RECN. Future work is required to validate top candidate genes such as RIC3 for involvement in cognitive maintenance. Hum Brain Mapp 35:4556–4565, 2014. © 2014 The Authors. Human Brain Mapping Published by Wiley Periodicals, Inc.
Replacing Sample Trimming with Boundary Correction in Nonparametric Estimation of First‐Price Auctions
Authors: Hickman Brent R. , Hubbard Timothy P. 
Published: March 2014

SummaryTwo‐step nonparametric estimators have become standard in empirical auctions. A drawback concerns boundary effects which cause inconsistencies near the endpoints of the support and bias in finite samples. To cope, sample trimming is typically used, which leads to non‐random data loss. Monte Carlo experiments show this leads to poor performance near the support boundaries and on the interior due to bandwidth selection issues. We propose a modification that employs boundary correction techniques, and we demonstrate substantial improvement in finite‐sample performance. We implement the new estimator using oil lease auctions data and find that trimming masks a substantial degree of bidder asymmetry and inefficiency in allocations. Copyright © 2014 John Wiley & Sons, Ltd.
Factors Affecting the Nuclear Localization of β‐Catenin in Normal and Malignant Tissue
Authors: Morgan Rhys G. , Ridsdale Jenna , Tonks Alex , Darley Richard L. 
Published: March 2014

ABSTRACTThe canonical Wnt signaling pathway has been the focus of intensive research because of its frequent dysregulation in human cancers. Much of this has been directed towards the aberrant expression and/or activity of the central mediator of this pathway, β‐catenin. In particular, the nuclear localization of β‐catenin and subsequent inappropriate activation of TCF/LEF‐mediated transcription appears to be an important process in both the establishment and maintenance of cancer stem cells. Despite this, the exact mechanisms controlling β‐catenin nuclear localization in both normal and malignant cells are poorly understood. This prospect article brings together the many mechanisms previously reported to regulate the nuclear localization of β‐catenin and how they are relevant to cancer. J. Cell. Biochem. 115: 1351–1361, 2014. © 2014 Wiley Periodicals, Inc.
Insulin‐Like Growth Factor Binding Protein 4 Enhances Cardiomyocytes Induction in Murine‐Induced Pluripotent Stem Cells
Authors: Xue Yuanyuan , Yan Yuan , Gong Hui , Fang Bo , Zhou Yin , Ding Zhiwen , Yin Peipei , Zhang Guoping , Ye Yong , Yang Chunjie , Ge Junbo , Zou Yunzeng 
Published: March 2014

ABSTRACTInsulin‐like growth factor binding protein 4 (IGFBP4) has been reported to play critical role in cardiomyocytes differentiation of embryonic stem cells (ESCs). But whether it promotes cardiomyocytes induction of iPSCs is unclear. In the present study, we aim to explore the role of IGFBP4 in the cardiogenesis of mouse iPSCs. We observed that IGFBP4 treatment at late stage during differentiation process of mouse iPSCs greatly enhanced the beating frequency of embryoid bodies (EBs). The expressions of Nkx2.5 (cardiac‐specific transcription factor), α‐MHC, α‐actinin, and Troponin I (cardiac‐specific protein) were significantly enhanced by IGFBP4 treatment. Immunostaining analysis showed that α‐MHC, TNNT2 and connexin 43, typical cardiac markers, were obviously expressed in isolated cardiomyocytes from iPSCs with or without IGFBP4 treatment. Further study revealed that IGFBP4 had little effect on the apoptosis of EBs, but it significantly promoted the proliferation of cardiomyocytes from iPSCs characterized by higher ratio EdU positive cells in differentiated cardiomyocytes. We next observed that IGFBP4 inhibited β‐catenin expression in cytosol of EBs at late stage during differentiation of iPSCs. Knockdown of β‐catenin using a siRNA technique promoted the proliferation of differentiated cardiomyocytes and enhanced cardiomyocytes induction of iPSCs, suggesting that the effect of IGFBP4 on cardiomyocytes differentiation of iPSCs has relationship with β‐catenin signaling pathway. In conclusion, IGFBP4 promotes cardiogenesis of iPSCs by enhancing the proliferation of differentiated cardiomyocytes through inhibiting β‐catenin signaling. J. Cell. Biochem. 115: 1495–1504, 2014. © 2014 Wiley Periodicals, Inc.
Precocial bird mothers shape sex differences in the behavior of their chicks
Authors: Pittet Florent , Houdelier Cécilia , Lumineau Sophie 
Published: March 2014

ABSTRACTCompared to mammals and altricial birds, evaluations of differences related to precocial birds' sex have often been limited to sexual behavior. Nevertheless, the extensive use of precocial bird models for investigating behavioral development issues requires in depth knowledge concerning the emergence of sex differences. Here, we evaluated behavioral differences between Japanese quail chicks in relation to their sex. We know that maternal influences are strong and early social environment shapes behavioral development in this species. Therefore, we investigated the emergence of sex differences in two very different early social situations to evaluate the impact of precocial bird mothers on sex differences. We assessed behavioral differences related to sex of (1) non‐brooded chicks and of (2) brooded chicks, using various ethological tests to evaluate emotional reactivity and social motivation differences related to sex. Our results show that both non‐brooded and brooded chicks present behavioral differences related to sex. They differed greatly according to chicks' early experience. Sex‐related differences between maternally deprived (non‐brooded) chicks concerned mainly fearfulness, whereas differences between male and female brooded chicks concerned mainly their reactions to social isolation. We hypothesize that mothers attenuate sex differences related to fearfulness by being a model for responses to fear‐eliciting situations and by providing a similar secure basis to both males and females. We finally propose that mothers induce differences in chicks' sociality by providing asymmetrical care toward males and females.J. Exp. Zool. 321A:265–275, 2014. © 2014 Wiley Periodicals, Inc.
Manganese G8 dendrimers targeted to oxidation‐specific epitopes: In vivo MR imaging of atherosclerosis
Authors: Nguyen Tuyen H. , Bryant Henry , Shapsa Ari , Street Hannah , Mani Venkatesh , Fayad Zahi A. , Frank Joseph A. , Tsimikas Sotirios , Briley‐Saebo Karen C. 
Published: March 2014

PurposeTo determine if manganese (Mn) G8 dendrimers targeted to oxidation‐specific epitopes (OSE) allow for in vivo detection of atherosclerotic lesions.Materials and MethodsOSE have been identified as key factors in atherosclerotic plaque progression and destabilization. Mn offers a potentially clinically translatable alternative to gadolinium‐based agents when bioretention and potential toxicity of gadolinium is anticipated. However, to be effective, high payloads of Mn must accumulate intracellularly in macrophages. It was hypothesized that G8 dendrimers targeted to OSE may allow delivery of high Mn payloads, thereby enabling in vivo detection of macrophage‐rich plaques. G8 dendrimers were modified to allow conjugation with MnDTPA (758 Mn ion) and the antibody MDA2 that is targeted to malondialdehyde (MDA)‐lysine epitopes. Both the untargeted and targeted G8 dendrimers were characterized and their in vivo efficacy evaluated in apoE−/− mice over a 96‐hour time period after bolus administration of a 0.05 mmol Mn/kg dose using a clinical MR system (3T).ResultsSignificant enhancement (normalized enhancement >60%, P = 0.0013) of atherosclerotic lesions was observed within a 72‐hour time period following administration of the targeted dendrimers. The presence of Mn within atherosclerotic lesions was confirmed using spectroscopic methods (>8 μg Mn/g). Limited signal attenuation (<18%) and Mn deposition (<1 μg Mn/g) was observed in the arterial wall following injection of the untargeted material.ConclusionThis study demonstrates that manganese‐labeled dendrimers, allowing a high Mn payload, targeted to OSE may allow in vivo image of atherosclerotic lesions. J. Magn. Reson. Imaging 2015;41:797–805. © 2014 Wiley Periodicals, Inc.
Elastoplastic model with loading memory surfaces (LMS) for monotonic and cyclic behaviour of geomaterials
Authors: di Benedetto Hervé , Blanc Matthieu , Tiouajni Samir , Ezaoui Alan 
Published: March 2014

SUMMARYA new elastoplastic model called loading memory surface based on the critical state concept and the multi‐surface framework is proposed for geomaterials. The model uses a hypoelastic formulation and two plastic mechanisms. The formulations of the model are made in three‐dimensional stress–strain space and work under both monotonic and cyclic loadings. A newly introduced formalism makes it possible to obtain the cyclic response directly from the monotonic loading one. This formalism gives a three‐dimensional generalization of the well‐known Masing rule. The model has been validated against test results of Hostun sand under several conditions: monotonic and cyclic, drained and undrained, tests in compression and in extension, and at different confining pressures and different densities. Copyright © 2014 John Wiley & Sons, Ltd.
Identification of cellular and genetic drivers of breast cancer heterogeneity in genetically engineered mouse tumour models
Authors: Melchor Lorenzo , Molyneux Gemma , Mackay Alan , Magnay Fiona‐Ann , Atienza María , Kendrick Howard , Nava‐Rodrigues Daniel , López‐García María Ángeles , Milanezi Fernanda , Greenow Kirsty , Robertson David , Palacios José , Reis‐Filho Jorge S , Smalley Matthew J 
Published: March 2014

AbstractThe heterogeneous nature of mammary tumours may arise from different initiating genetic lesions occurring in distinct cells of origin. Here, we generated mice in which Brca2, Pten and p53 were depleted in either basal mammary epithelial cells or luminal oestrogen receptor (ER)‐negative cells. Basal cell‐origin tumours displayed similar histological phenotypes, regardless of the depleted gene. In contrast, luminal ER‐negative cells gave rise to diverse phenotypes, depending on the initiating lesions, including both ER‐negative and, strikingly, ER‐positive invasive ductal carcinomas. Molecular profiling demonstrated that luminal ER‐negative cell‐origin tumours resembled a range of the molecular subtypes of human breast cancer, including basal‐like, luminal B and ‘normal‐like’. Furthermore, a subset of these tumours resembled the ‘claudin‐low’ tumour subtype. These findings demonstrate that not only do mammary tumour phenotypes depend on the interactions between cell of origin and driver genetic aberrations, but also multiple mammary tumour subtypes, including both ER‐positive and ‐negative disease, can originate from a single epithelial cell type. This is a fundamental advance in our understanding of tumour aetiology. © 2014 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Improved current stability in multi‐mesa‐channel AlGaN/GaN transistors
Authors: Asubar Joel , Ohi Kota , Nishiguchi Kenya , Hashizume Tamotsu 
Published: March 2014

AbstractWe present further experimental results that demonstrate the superior current stability of multi‐mesa‐channel (MMC) AlGaN/GaN HEMTs over their conventional planar counterparts. Pulsed ID‐VDS measurements revealed almost overlapping ID‐VDS curves for the MMC device even with increasing drain‐to‐source quiescent bias VDSq with gate‐to‐source quiescent bias VGSq kept constant. With all other device dimensions equal, the MMC device exhibited less on‐resistance RON change with varying gate‐to‐drain spacing LGD. This could be the key to understanding why the MMC device operation is relatively immune to current collapse, a stability issue widely believed to be connected to surface charging at the gate‐drain access region. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First experience with a fully automated extraction system for simultaneous on‐line direct tandem mass spectrometric analysis of amino acids and (acyl‐)carnitines in a newborn screening setting
Authors: Fingerhut Ralph , Silva Polanco Maria Lucia , Silva Arevalo Gabriel De Jesus , Swiderska Magdalena A. 
Published: March 2014

RATIONALEFor Newborn Screening (NBS) programs all over the world whole blood dried on filter paper, also referred to as dried blood spots (DBS), has been the standard specimen for decades. In recent years DBS have attracted the attention of pharmaceutical companies, mostly due to the low volume of collected sample and simplified, therefore more cost‐efficient, transportation requirements. However, the classical NBS workflow did not totally fulfil the needs of their studies, especially with respect to high‐throughput unassisted sample processing for tandem mass spectrometric (MS/MS) analysis. Automated on‐line extraction systems for direct analysis have already been tested and proved to be suitable for these pharmaceutical applications.METHODSThe suitability of the automated CAMAG DBS‐MS 500 interface for simultaneous detection of amino acids and (acyl‐)carnitines has been tested together with an Acquity TQD tandem mass spectrometer from Waters and MassChrom stable isotope labelled internal standards from Chromsystems. No chromatographic sample treatment was applied; instead, the extract was directly injected into the MS/MS instrument. The feasibility of the instrumental setting for the routine newborn screening was tested on original samples coming from previously diagnosed patients.RESULTSThe performance of the automated extraction technique and its application in preliminary quantitative screening for amino acids and (acyl‐)carnitines for NBS showed very promising results. Several samples from patients, each diagnosed with one of four different inborn errors of metabolism (IEM), were tested and the correlation with the conventional punch‐and‐elute approach was very good.CONCLUSIONSAlthough the presented method still needs further optimization, our study clearly shows the possibility to use direct on‐line analysis in the NBS setting. Our report on direct on‐line analysis of newborn samples is a first approach in the development of a fully automated screening method for NBS analysis. With regard to the chemical properties of the analytes, the study resulted in a readily applicable screening method. Copyright © 2014 John Wiley & Sons, Ltd.
Performance evaluation of collision avoidance schemes in ad hoc networks
Authors: Bhandare Suryakant , Brahim Taha Ben , Biaz Saad , Agrawal Prathima 
Published: March 2014

AbstractIEEE 802.11 distributed coordination function (DCF) is a popular protocol used for the physical and medium access control layers in most ad hoc networks. DCF employs carrier sense multiple access with collision avoidance and a binary slotted exponential back off. It has been observed that the hidden and exposed terminal problems among stations degrade DCF's performance in terms of throughput and fairness. Hence, the effectiveness of the IEEE 802.11 DCF mechanism in ad hoc networks has attracted many research studies. Many collision avoidance schemes were proposed to address the IEEE 802.11 DCF weaknesses as the performance of the medium access control layer directly impacts the performance of higher‐layer protocols and hence the entire network. An evaluation of representative schemes under the same conditions will be helpful in understanding the limitations and strengths of these schemes. This paper surveys various collision avoidance schemes, classify them on the basis of their mechanism, and then provide a comparative study of representative schemes based on their performance. They are evaluated on a chain topology, a pair topology, and a random topology with static environment to measure their throughput, fairness, collision probabilities, and delay. On the basis of the evaluation, we conclude that gentle DCF is the best scheme that has lesser collisions with improved throughput and fairness. A comparison with the legacy carrier sense multiple access with collision avoidance suggests that these proposed schemes do tend to be promising and would inspire future researchers who are interested to find solutions to the age‐old collision and fairness issues in ad hoc networks. Copyright © 2014 John Wiley & Sons, Ltd.
A link graph‐based approach to identify forum spam
Authors: Shin Youngsang , Myers Steven , Gupta Minaxi , Radivojac Predrag 
Published: March 2014

ABSTRACTWeb spammers have taken note of the popularity of public forums such as blogs, wikis, webboards, and guestbooks. They are now exploiting them with the purpose of driving traffic to their malicious or fraudulent websites, such as those used for phishing, distributing malware, or selling counterfeit pharmaceuticals. A popular technique they use is to spam these forums with URLs to their spam websites. We consider the problem of classifying URLs posted to forums as spam or legitimate by considering the link structure of the graph rooted at the posted URL. We investigate various graph metrics and associated metadata to analyze link structures. To lessen noisy structural characteristics of the link graphs for spam classification, we also examine two techniques: differing depths and aggregating sub‐graphs of the link graphs. Our results show that a support vector machine classifier based on combinations of graph metrics and metadata of link graphs can achieve a pragmatically high performance in forum spam detection. Copyright © 2014 John Wiley & Sons, Ltd.