bluuebunny/crossref_metadata_2025 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

Climate 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.
Intrahepatic B‐cell follicles of chronically hepatitis C virus‐infected individuals lack signs of an ectopic germinal center reaction
Authors: Tucci Felicia A. , Broering Ruth , Lutterbeck Melanie , Schlaak Joerg F. , Küppers Ralf
Published: March 2014

Chronic infection with hepatitis C virus (HCV) often affects the B‐cell compartment, leading to the occurrence of autoimmunity and B‐cell lymphoproliferation, in particular mixed cryoglobulinemia and B‐cell lymphomas. HCV presumably causes these lymphoproliferations by chronic antigenic stimulation and/or direct mutagenic effects on B cells. It has been speculated that the interaction of HCV with B cells and the expansion of antigen‐triggered B cells happens in germinal center‐like structures in the livers of HCV carriers. We studied rearranged immunoglobulin VH genes from seven B‐cell follicles microdissected from the livers of three unselected chronic HCV patients. The follicles consisted of polyclonal naive and memory B‐cell populations with only rare indication of minor clonal expansions and no evidence for active somatic hypermutation. Frequent detection of VH rearrangements using the VH1‐69 gene segment nevertheless indicated that at least a fraction of the B cells is HCV‐specific and/or autoreactive. Thus, the typical intrahepatic B‐cell follicles in chronic HCV carriers do not function as ectopic germinal centers for clonal expansion and affinity maturation of B cells. Hence, autoreactive and HCV‐specific B‐cell clones might either develop in secondary lymphoid organs or in intrahepatic follicles only under particular, yet undefined, circumstances.
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

Objective

Identify genetic factors associated with cognitive maintenance in late life and assess their association with gray matter (GM) volume in brain networks affected in aging.

Methods

We 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.

Results

The 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).

Conclusions

These 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.
Surviving a Lawsuit Against a Counseling Program: Lessons Learned From Ward v. Wilbanks
Authors: Dugger Suzanne M. , Francis Perry C.
Published: March 2014

This article features information about a lawsuit brought by a former student against Eastern Michigan University and its counseling program. In addition to describing the major elements of the lawsuit, the authors reflect on lessons learned and offer recommendations for other counseling programs.
“I Am My Own Gender”: Resilience Strategies of Trans Youth
Authors: Singh Anneliese A. , Meng Sarah E. , Hansen Anthony W.
Published: March 2014

Nineteen trans youth participated in a phenomenological study of their resilience strategies for navigating stressors in their lives. The authors identified 5 supports and 6 threats to participants’ resilience. The 5 themes of resilience were: (a) ability to self‐define and theorize one's gender, (b) proactive agency and access to supportive educational systems, (c) connection to a trans‐affirming community, (d) reframing of mental health challenges, and (e) navigation of relationships with family and friends. The 6 major threats to participants’ resilience were: (a) experiences of adultism, (b) health care access challenges, (c) emotional and social isolation, (d) employment discrimination, (e) limited access to financial resources, and (f) gender policing.
Replacing Sample Trimming with Boundary Correction in Nonparametric Estimation of First‐Price Auctions
Authors: Hickman Brent R. , Hubbard Timothy P.
Published: March 2014

Two‐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

The 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

Insulin‐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.
Electronegativity estimator built on QTAIM‐based domains of the bond electron density
Authors: Ferro‐Costas David , Pérez‐Juste Ignacio , Mosquera Ricardo A.
Published: March 2014

The electron localization function, natural localized molecular orbitals, and the quantum theory of atoms in molecules have been used all together to analyze the bond electron density (BED) distribution of different hydrogen‐containing compounds through the definition of atomic contributions to the bonding regions. A function, gAH, obtained from those contributions is analyzed along the second and third periods of the periodic table. It exhibits periodic trends typically assigned to the electronegativity (χ), and it is also sensitive to hybridization variations. This function also shows an interesting S shape with different χ‐scales, Allred–Rochow's being the one exhibiting the best monotonical increase with regard to the BED taken by each atom of the bond. Therefore, we think this χ can be actually related to the BED distribution. © 2014 Wiley Periodicals, Inc.
CONNECTIONS AND COMMUNITIES IN VIRTUAL WORLDS DESIGNED FOR CHILDREN
Authors: Reich Stephanie M. , Black Rebecca W. , Korobkova Ksenia
Published: March 2014

As more and more people are interacting through online spaces, questions emerge as to how these computer‐mediated interactions impact people's social connections and ability to form communities. Some of the online spaces that are exceedingly popular are virtual worlds designed specifically for children. This study, using participant‐observations and content analysis, explored how users communicate, form connections, and develop community in children's virtual worlds. This 3‐year study found that users find creative ways to bypass design features to share personal information, establish group membership, and build connections both in the virtual worlds and on their accompanying fan sites. These findings provide valuable insight into the social affordances of popular online spaces for children, as well as expand modern‐day conceptualizations of social connection and community.
HOPE AND LIFE SATISFACTION AMONG UNDERPRIVILEGED CHILDREN IN HONG KONG: THE MEDIATING ROLE OF PERCEIVED COMMUNITY SUPPORT
Authors: Ng Eddie C. W. , Chan Charles C. , Lai Man Kin
Published: March 2014

Poverty is a long‐standing problem in developing and developed countries alike. It not only affects people's health and well‐being but may also create the social burden if not addressed appropriately. The present study of 150 children (aged 7–12 years) examines how the disadvantaged children's personal attribute interacts with the environment in developing their well‐being. Structural equation modeling provides evidence to our understanding of children who grow up in poverty. Not only are both hopeful thinking and perceived community support predictive of the children's satisfaction with life, but the perceived community support also plays a critical mediating role in the influence of hope on life satisfaction. This finding matches resilience literature, that to overcome great odds and to achieve well‐being, factors both within the individual and external sources of support, are also important in interactional ways. It also highlights the critical role of availability of community resources and support.
Precocial bird mothers shape sex differences in the behavior of their chicks
Authors: Pittet Florent , Houdelier Cécilia , Lumineau Sophie
Published: March 2014

Compared 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.
Turning Men into Machines? Scientific Management, Industrial Psychology, and the “Human Factor”
Authors: Derksen Maarten
Published: March 2014

In the controversy that broke out in 1911 over Frederick W. Taylor's scientific management, many critics contended that it ignored “the human factor” and reduced workers to machines. Psychologists succeeded in positioning themselves as experts of the human factor, and their instruments and expertise as the necessary complement of Taylor's psychologically deficient system. However, the conventional view that the increasing influence of psychologists and other social scientists “humanized” management theory and practice needs to be amended. Taylor's scientific management was not less human than later approaches such as Human Relations, but it articulated the human factor differently, and aligned it to its own instruments and practices in such a way that it was at once external to them and essential to their functioning. Industrial psychologists, on the other hand, at first presented themselves as engineers of the human factor and made the human mind an integral part of management.
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

Purpose

To determine if manganese (Mn) G8 dendrimers targeted to oxidation‐specific epitopes (OSE) allow for in vivo detection of atherosclerotic lesions.

Materials and Methods

OSE 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).

Results

Significant 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.

Conclusion

This 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.
Nanocomposite Membranes for Polymer Electrolyte Fuel Cells
Authors: Krishnan Nagappan Nambi , Henkensmeier Dirk , Jang Jong Hyun , Kim Hyoung‐Juhn
Published: March 2014

Nanoparticles are known to play several roles as polymer fillers, among them reducing the bulk material price or adjusting the mechanical properties. In ion conducting polymer membranes, nanoparticles are also used to manipulate the water balance and fuel permeability of the membrane and to increase the ion conductivity. Suitable materials are metal oxides (SiO2, TiO2, etc.), electron deficient boron nitride or ion conductive functionalized metal oxides (SZrO2, HPASiO2, etc.). This article shows which membrane properties can be addressed by adding nanoparticles and describes the underlying mechanisms.
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

A 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

The 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

We 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

RATIONALE

For 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.

METHODS

The 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.

RESULTS

The 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.

CONCLUSIONS

Although 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

IEEE 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

Web 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.
Nanostructured Polymeric Coatings Based on Chitosan and Dopamine‐Modified Hyaluronic Acid for Biomedical Applications
Authors: Neto Ana I. , Cibrão Ana C. , Correia Clara R. , Carvalho Rita R. , Luz Gisela M. , Ferrer Gloria G. , Botelho Gabriela , Picart Catherine , Alves Natália M. , Mano João F.
Published: March 2014

In a marine environment, specific proteins are secreted by mussels and used as a bioglue to stick to a surface. These mussel proteins present an unusual amino acid 3,4‐dihydroxyphenylalanine (known as DOPA). The outstanding adhesive properties of these materials in the sea harsh conditions have been attributed to the presence of the catechol groups present in DOPA. Inspired by the structure and composition of these adhesive proteins, dopamine‐modified hyaluronic acid (HA‐DN) prepared by carbodiimide chemistry is used to form thin and surface‐adherent dopamine films. This conjugate was characterized by distinct techniques, such as nuclear magnetic resonance and ultraviolet spectrophotometry. Multilayer films are developed based on chitosan and HA‐DN to form polymeric coatings using the layer‐by‐layer methodology. The nanostructured films formation is monitored by quartz crystal microbalance. The film surface is characterized by atomic force microscopy and scanning electron microscopy. Water contact angle measurements are also conducted. The adhesion properties are analyzed showing that the nanostructured films with dopamine promote an improved adhesion. In vitro tests show an enhanced cell adhesion, proliferation and viability for the biomimetic films with catechol groups, demonstrating their potential to be used in distinct biomedical applications.
Selective Formation of Carbon‐Coated, Metastable Amorphous ZnSnO3 Nanocubes Containing Mesopores for Use as High‐Capacity Lithium‐Ion Battery
Authors: Han Fei , Li Wen‐Cui , Lei Cheng , He Bin , Oshida Kyoichi , Lu An‐Hui
Published: March 2014

Mesoporous and amorphous ZnSnO3 nanocubes of ∼37 nm size coated with a thin porous carbon layer have been prepared using monodisperse ZnSn(OH)6 as the active precursor and low‐temperature synthesized polydopamine as the carbon precursor. The small single nanocubes cross‐link with each other to form a continuous conductive framework and interconnected porous channels with macropores of 74 nm width. Because of its multi‐featured nanostructure, this material exhibits greatly enhanced integration of reversible alloying/de‐alloying (i.e., transformation of Li4.4Sn and LiZn to Sn and Zn) and conversion (i.e., oxidation of Sn and Zn to ZnSnO3) reaction processes with an extremely high capacity of 1060 mA h g−1 for up to 100 cycles. A high reversible capacity of 650 and 380 mA h g−1 can also be delivered at rates of 2 and 3 A g−1, respectively. This excellent electrochemical performance is attributed to the small particle size, well‐developed mesoporosity, the amorphous nature of the ZnSnO3 and the continuous conductive framework produced by the interconnected carbon layers.
Tradeoff between energy efficiency and spectral efficiency in a delay constrained wireless system
Authors: Chen Xue , Hu Rose Qingyang , Wu Geng , Li Qian Clara
Published: March 2014

Because of the inevitable trend of green networking, energy efficiency (EE) is quickly becoming one of the key performance metrics to evaluate wireless communication systems, together with spectrum efficiency (SE) and quality of service (QoS) that have been traditionally used. This paper studies the fundamental tradeoff between EE and SE in the presence of statistical QoS requirements in wireless transmission systems. Earlier studies have shown that the performance with QoS requirements in the wireless transmission can be measured through effective capacity, which can capture the physical layer fading channel characteristics in the link layer QoS requirements, such as delay and data rate. Under this context, SE is defined as effective capacity per unit frequency bandwidth, and EE is defined as energy consumed per effective capacity bit. Both circuit power and transmission power are considered in the energy model, based on which we derive the quasi‐convex generalized EE formulation. To exploit the tradeoff between EE and SE with QoS considerations, we propose a generic close‐form approximation for EE–SE formulation by employing a curve fitting approach. The impacts of QoS and circuit power consumption on EE–SE tradeoff are respectively analyzed. QoS requirement and circuit power consumption affect the EE–SE tradeoff differently. In the low‐SNR regime, circuit power shows more impact on the EE–SE tradeoff, whereas QoS impacts EE–SE tradeoff more in the high‐SNR regime. Copyright © 2014 John Wiley & Sons, Ltd.
Convergence and stability in balanced norms of finite element methods on Shishkin meshes for reaction‐diffusion problems
Authors: Roos H.‐G. , Schopf M.
Published: March 2014

Error estimates of finite element methods for reaction‐diffusion problems are often realized in the related energy norm. In the singularly perturbed case, however, this norm is not adequate. A different scaling of the H1 seminorm leads to a balanced norm which reflects the layer behavior correctly. We prove error estimates in balanced norms and investigate also stability questions. Especially, we propose a new C0 interior penalty method with improved stability properties in comparison with the Galerkin FEM.
A General Solution Framework for Component-Commonality Problems
Authors: Boysen Nils , Scholl Armin
Published: March 2014

Component commonality — the use of the same version of a component across multiple products — is being increasingly considered as a promising way to offer high external variety while retaining low internal variety in operations. However, increasing commonality has both positive and negative cost effects, so that optimization approaches are required to identify an optimal commonality level. As components influence to a greater or lesser extent nearly every process step along the supply chain, it is not surprising that a multitude of diverging commonality problems is being investigated in literature, each of which are developing a specific algorithm designed for the respective commonality problem being considered. The paper on hand aims at a general framework which is flexible and efficient enough to be applied to a wide range of commonality problems. Such a procedure based on a two-stage graph approach is presented and tested. Finally, flexibility of the procedure is shown by customizing the framework to account for different types of commonality problems.
Cosmetic Result and Overall Satisfaction after Minimally Invasive Video‐assisted Thyroidectomy (MIVAT) versus Robot‐assisted Transaxillary Thyroidectomy (RATT): A Prospective Randomized Study
Authors: Materazzi Gabriele , Fregoli Lorenzo , Manzini Gabriele , Baggiani Angelo , Miccoli Mario , Miccoli Paolo
Published: March 2014

Background

No studies have compared robot‐assisted transaxillary thyroidectomy (RATT) and minimally invasive video‐assisted thyroidectomy (MIVAT) regarding cosmetic outcome and satisfaction

Methods

Patients matching the inclusion criteria (benign nodule less than 4 cm and thyroid volume less than 30 mL) were randomly allotted to undergo MIVAT (group A) or RATT (group B). Cosmetic result, overall satisfaction, operative time, and complications were evaluated.

Results

A total of 62 patients underwent hemithyroidectomy (30 in group A and 32 in group B). All patients were women, with the exception of one man in each group. The mean patient age was 36.9 years (group A) and 32.5 years (group B). Total operative time (intubation–extubation) was shorter in group A (71.6 min) than in group B (120.4 min). Complications included one transient laryngeal nerve injury in each group and one subcutaneous hematoma in group B. Postoperative hospital stay was longer in group B (1.85 days) than in group A (1.15 days). On the PASQ questionnaire, “scar appearance” and “satisfaction with appearance” scores were better in group A than in group B. In the Short Form (SF‐36) 36‐Item Health Survey Questionnaire, domains of “social activity” and “general health” were better in group B than in group A, whereas “bodily pain” scored higher in group B than in group A.

Conclusions

RATT seems not to supersede MIVAT in terms of satisfaction when comparing two groups of patients undergoing thyroidectomy for benign disease.
Prognostic Factors of Patients with Thymic Carcinoma After Surgery: A Retrospective Analysis of 58 Cases
Authors: Wang Shuai , Wang Zhou , Liu Xiangyan , Wang Dong , Liu Fanying
Published: March 2014

Background

Thymic carcinoma is reputed to carry a poor prognosis. Although few scholars have studied the prognosis of thymic carcinoma, the prognostic factors of patients after surgery are not well established. We analyze the prognostic significance of undetermined factors to predict the survival of patients after surgery.

Methods

We reviewed 351 cases of thymic epithelial tumor treated with surgery at a single institution in China from 1992 to 2011. A total of 58 patients were histopathologically reconfirmed as having thymic carcinoma. Clinicopathological characteristics and treatment modalities were reviewed. During the follow‐up, with a median of 65.8 months, survival time was analyzed using the Kaplan–Meier method. Univariate and multivariate analysis were performed to identify prognostic factors.

Results

The overall 3‐, 5‐, and 10‐year survival rate was 69.0, 43.1, and 12.1 %, respectively. The Log‐rank test revealed that Masaoka stage (p = 0.000), histology group (p = 0.000), completeness of the resection (p = 0.000), great vessel invasion (p = 0.000), and presence of symptoms (p = 0.003) were significant prognostic factors in all patients. However, tumor size (p = 0.086), age (p = 0.677), sex (p = 0.706), smoking (p = 0.065), and alcohol (p = 0.875) were not prognostic factors. A Cox proportional hazards regression model showed that Masaoka stage (hazard ratio = 15.640, p = 0.000) and completeness of the resection (hazard ratio = 18.303, p = 0.000) were the only independent prognostic factors.

Conclusions

The Masaoka stage and completeness of the resection were independent prognostic factors that predicted long‐term survival of patients with thymic carcinoma treated with surgery.
Preparation of przewalskinic acid A from salvianolic acid B using a crude enzyme from an Aspergillus oryzae strain
Authors: Liu Chunying , Jin Yinghua , Yu Hongshan , Sun Changkai , Zhou Shuiping , Zhu Yonghong , Xu Longquan , Yu Chong , Jin Fengxie
Published: March 2014

Przewalskinic acid A is a rare, water-soluble, and highly biologically active ingredient found, thus far, only in the Salvia przewalskii Maxim herb; however, the content in S. przewalskii herb is very low. In order to obtain useful quantities of przewalskinic acid A, the biotransformatin of salvianolic acid B from Salvia miltiorrhiza root (danshen in Chinese) into przewalskinic acid A was studied using a crude enzyme produced from Aspergillus oryzae D30s strain. The crude enzyme from the A. oryzae strain hydrolyzed salvianolic acid B into przewalskinic acid A and danshensu. The preparation afforded 31.3 g przewalskinic acid A (91.0 % purity) and 13.1 g danshensu (95 % purity) from 75 g salvianolic acid B. The preparation of przewalskinic acid A was therefore very successful with a yield of over 86 %, but the yield of danshensu was only 33 %. The product przewalskinic acid A was identified using ultra-performance liquid chromatography–mass spectrometry (UPLC–MS) and NMR.
Oxalic acid production by citric acid-producing Aspergillus niger overexpressing the oxaloacetate hydrolase gene oahA
Authors: Kobayashi Keiichi , Hattori Takasumi , Honda Yuki , Kirimura Kohtaro
Published: March 2014

The filamentous fungus Aspergillus niger is used worldwide in the industrial production of citric acid. However, under specific cultivation conditions, citric acid-producing strains of A. niger accumulate oxalic acid as a by-product. Oxalic acid is used as a chelator, detergent, or tanning agent. Here, we sought to develop oxalic acid hyperproducers using A. niger as a host. To generate oxalic acid hyperproducers by metabolic engineering, transformants overexpressing the oahA gene, encoding oxaloacetate hydrolase (OAH; EC 3.7.1.1), were constructed in citric acid-producing A. niger WU-2223L as a host. The oxalic acid production capacity of this strain was examined by cultivation of EOAH-1 under conditions appropriate for oxalic acid production with 30 g/l glucose as a carbon source. Under all the cultivation conditions tested, the amount of oxalic acid produced by EOAH-1, a representative oahA-overexpressing transformant, exceeded that produced by A. niger WU-2223L. A. niger WU-2223L and EOAH-1 produced 15.6 and 28.9 g/l oxalic acid, respectively, during the 12-day cultivation period. The yield of oxalic acid for EOAH-1 was 64.2 % of the maximum theoretical yield. Our method for oxalic acid production gave the highest yield of any study reported to date. Therefore, we succeeded in generating oxalic acid hyperproducers by overexpressing a single gene, i.e., oahA, in citric acid-producing A. niger as a host.
1‐Sarcosine–angiotensin II infusion effects on food intake, weight loss, energy expenditure, and skeletal muscle UCP3 gene expression in a rat model
Authors: Cichello S. A. , Weisinger R. S. , Schuijers J. , Jois M.
Published: March 2014

Background

There are a myriad of proteins responsible for modulation of expenditure of energy. Angiotensin II (Ang II) is a vital component of renin‐angiotensin system that affects blood pressure and also linked to both cachexia and obesity via fat and muscle metabolism. Previous research suggests that the direct action of Ang II is on the brain, via angiotensin II type 1 receptor protein, affecting food intake and energy expenditure. The objective of the study is to investigate the effect of 1‐sarcosine (SAR)‐Ang II infusion on energy expenditure and metabolism in a rat model of congestive heart failure cachexia.

Methods

Adult female rats of the Sprague Dawley strain (n = 33) were used (11 pair‐fed control, 12 ad libitum and 10, 1‐sarcosine–angiotensin II‐infused rats). Body weight, faecal excretion, feed intake (in grams), water intake (in milliliters) and urine excreted were recorded daily. The measurements were recorded in three different periods (4 days prior to surgery, “pre‐infusion”; day of surgery and 5 days postsurgery, “infusion period”; days 7 to 14, “recovery” period). Different analytical methods were used to measure energy expenditure per period, uncoupling protein 3 mRNA expression, crude protein and adipose tissue body composition.

Results

During the infusion period, the SAR–Ang II group experienced rapid weight loss (p < 0.05) in comparison to the ad libitum and pair‐fed groups. The SAR–Ang II group displayed lower (p < 0.05) body fat content (in percent) than the controls. There was also increased (p < 0.05) uncoupling protein 3 (UCP3) mRNA expression in the SAR–Ang II group and pair‐fed group when compared to the controls.

Conclusion

In summary, the results suggest that SAR–Ang II infusion impairs appetite and decreases body weight by wasting predominantly adipose tissue, which may be due to elevated energy expenditure via mitochondrial uncoupling (UCP3 protein activity).
Effects of platinum content on tribological properties of platinum/nitrogen doped diamond-like carbon thin films deposited via magnetron sputtering
Authors: Khun Nay Win , Liu Erjia
Published: March 2014

Platinum (Pt) and nitrogen (N) were co-incorporated in diamond-like carbon (DLC) thin films using a magnetron sputtering system to form PtN-DLC thin films for tribological applications. The Pt content in the PtN-DLC films prepared on Si substrates was controlled by varying RF power applied to a Pt target at a fixed N2 flow rate. The tribological properties of the PtN-DLC films were investigated with respect to the Pt content in the films. The uncoated Si substrate surface tested against a steel ball of 6 mm in diameter had significant abrasive and fatigue wear, while no significant wear was found on the N-DLC coated sample surface, indicating that the N-DLC film effectively prevented its underlying Si substrate from wear. However, the incorporation of Pt in the N-DLC films reduced the wear resistance of the films by degrading sp3-bonded cross-linking structures of the films so that significant wear tracks were found on the surfaces of the PtN-DLC films. Therefore, the increased radio frequency (RF) power applied to the Pt target decreased the wear resistance of the PtN-DLC films as a result of the increased Pt content.
Characterization of microstructure, toughness, and chemical composition of friction-welded joints of UNS S32205 duplex stainless steel
Authors: Ajith Puthuparambil Madhavan , Sathiya Paulraj , Aravindan Sivanandam
Published: March 2014

Friction welding is a solid-state joining process which is applied extensively because of its advantages such as low heat input, efficient application, ease in manufacturing, and environmental friendliness. The present study investigates the mechanical and metallurgical properties of UNS S32205 duplex stainless steel friction-welded joints. The process parameters, namely friction pressure, upsetting pressure, and rotational speed are individually varied from low level to high level (within the range of the machine setup) and their effects on the joint properties are analyzed. The partial-deformation zone had higher hardness than the weld and base metal. The toughness of the joints was evaluated at room temperature and at subzero temperature conditions. The impact toughness of the friction-welded joints was found to be superior to fusion-joined duplex stainless steel in room and cryogenic conditions.