bluuebunny/crossref_metadata_2025 huggingface dataset:
The self-organization of grid cells in 3D
Authors: Stella Federico , Treves Alessandro
Published: March 2015

Do we expect periodic grid cells to emerge in bats, or perhaps dolphins, exploring a three-dimensional environment? How long will it take? Our self-organizing model, based on ring-rate adaptation, points at a complex answer. The mathematical analysis leads to asymptotic states resembling face centered cubic (FCC) and hexagonal close packed (HCP) crystal structures, which are calculated to be very close to each other in terms of cost function. The simulation of the full model, however, shows that the approach to such asymptotic states involves several sub-processes over distinct time scales. The smoothing of the initially irregular multiple fields of individual units and their arrangement into hexagonal grids over certain best planes are observed to occur relatively quickly, even in large 3D volumes. The correct mutual orientation of the planes, though, and the coordinated arrangement of different units, take a longer time, with the network showing no sign of convergence towards either a pure FCC or HCP ordering.
Oxyntomodulin regulates resetting of the liver circadian clock by food
Authors: Landgraf Dominic , Tsang Anthony H , Leliavski Alexei , Koch Christiane E , Barclay Johanna L , Drucker Daniel J , Oster Henrik
Published: March 2015

Circadian clocks coordinate 24-hr rhythms of behavior and physiology. In mammals, a master clock residing in the suprachiasmatic nucleus (SCN) is reset by the light–dark cycle, while timed food intake is a potent synchronizer of peripheral clocks such as the liver. Alterations in food intake rhythms can uncouple peripheral clocks from the SCN, resulting in internal desynchrony, which promotes obesity and metabolic disorders. Pancreas-derived hormones such as insulin and glucagon have been implicated in signaling mealtime to peripheral clocks. In this study, we identify a novel, more direct pathway of food-driven liver clock resetting involving oxyntomodulin (OXM). In mice, food intake stimulates OXM secretion from the gut, which resets liver transcription rhythms via induction of the core clock genes Per1 and 2. Inhibition of OXM signaling blocks food-mediated resetting of hepatocyte clocks. These data reveal a direct link between gastric filling with food and circadian rhythm phasing in metabolic tissues.
Tracking the weathering of basalts on Mars using lithium isotope fractionation models
Authors: Fairén Alberto G. , Losa‐Adams Elisabeth , Gil‐Lozano Carolina , Gago‐Duport Luis , Uceda Esther R. , Squyres Steven W. , Rodríguez J. Alexis P. , Davila Alfonso F. , McKay Christopher P.
Published: March 2015

Lithium (Li), the lightest of the alkali elements, has geochemical properties that include high aqueous solubility (Li is the most fluid mobile element) and high relative abundance in basalt‐forming minerals (values ranking between 0.2 and 12 ppm). Li isotopes are particularly subject to fractionation because the two stable isotopes of lithium—7Li and 6Li—have a large relative mass difference (∼15%) that results in significant fractionation between water and solid phases. The extent of Li isotope fractionation during aqueous alteration of basalt depends on the dissolution rate of primary minerals—the source of Li—and on the precipitation kinetics, leading to formation of secondary phases. Consequently, a detailed analysis of Li isotopic ratios in both solution and secondary mineral lattices could provide clues about past Martian weathering conditions, including weathering extent, temperature, pH, supersaturation, and evaporation rate of the initial solutions in contact with basalt rocks. In this paper, we discuss ways in which Martian aqueous processes could have lead to Li isotope fractionation. We show that Li isotopic data obtained by future exploration of Mars could be relevant to highlighting different processes of Li isotopic fractionation in the past, and therefore to understanding basalt weathering and environmental conditions early in the planet's history.
Statistical Analysis ofDNAMicroarray Data
Authors: Datta Susmita , Gill Ryan
Published: March 2015

Not too long ago, geneticists dealt with only one or two genes simultaneously. Microarray technology is the first of its kind by which scientists were able to study the expressions of thousands of genes in a single experiment. However, owing to its novelty and its capability of measuring such a large volume of information, it has gone through several stages of perfection at every stage of data analysis starting from data normalization to gene annotation. Statisticians and computational biologists made significant contributions toward these. Earlier, we have provided a very brief summary of some of the important statistical work in the field.
Interval Censoring
Authors: Gerds Thomas A. , Meier‐Hirmer Carolina
Published: March 2015

In survival or time‐to‐event analysis, interval censoring occurs if the time of an event is the endpoint of interest that cannot be observed exactly for each patient but occurred chronologically between two follow‐ups. Information of the event status is typically collected by periodically performing clinical examinations or laboratory tests. Events of interest can be the onset of a disease, infection, the recurrence of a tumor, and other changes in the course of a disease. As, in the clinical practice, the number of examination times is typically different among patients, most frequently one has to deal with “mixed‐case” interval censoring. This term refers to situations where some of the observations are exact event times, some are right‐ or left‐censored, and others are really censored to intervals. The term interval censoring is often used to generally describe data consisting of such a mixture.
Editing Statistical Data
Authors: Naus Joseph
Published: March 2015

There are several statistical and data‐processing techniques that exist in the literature to monitor data and also to detect and correct errors in them. This area of Statistics has developed its own extensive terminology. In this entry, the terminology and the important techniques used in data editing and imputation are described.
Graphical Displays
Authors: Martin Michael A. , Welsh A. H.
Published: March 2015

Graphical methods are fundamental tools of modern data analysis. Graphics are useful for communicating complex information quickly and easily, and are thus excellent tools for describing data and for providing direction in data analysis. They are essential tools for building statistical models from data, and for assessing model adequacy. This article surveys the use of statistical graphics in describing data and for statistical modeling, including models for relating variables, spatiotemporal dependence, and survival data. Graphics are also critical tools for visualizing and analyzing high‐dimensional data. The article illustrates the use of graphics in statistical modeling through numerous examples drawn from the life sciences.
Optimization and Nonlinear Equations
Authors: Smyth Gordon K.
Published: March 2015

Optimization means finding the argument that minimizes or maximizes a given function such as a likelihood function or a sum of squares. Many optimization algorithms are derived from algorithms that solve the nonlinear equations defined by setting the derivative of the objective function equal to zero. This article discusses a number of methods for unconstrained optimization, including bisection and golden search in the univariate case and Newton's method and quasi‐Newton algorithms in the multivariate case. Applications to maximum likelihood estimation, Fisher's method of scoring, nonlinear regression, and generalized linear models are described. Restricted step modifications are discussed for preventing divergence of Newton‐type algorithms. A number of derivative‐free methods are discussed, including the Nelder–Mead simplex method, methods with numeric derivatives, conjugate methods, and the EM algorithm.
Saddlepoint Approximation: Introduction
Authors: Kolassa John E.
Published: March 2015

Saddlepoint approximations are asymptotic approximations to the density or tail‐area probability of a statistic. The basic result, using the cumulant generating function for a univariate random variable, may be generalized to apply to random vectors and developed to deal with tail probabilities, conditional distributions, and discrete random variables.
Teaching Statistics to Psychologists in an Online World
Authors: Spilich George
Published: March 2015

This is an exciting time for those who teach statistics to undergraduate and graduate students in the behavioral sciences. This article traces the course of five revolutions in how we teach statistics, starting with the introduction of mechanical calculators, continuing through the development of statistical packages, and culminating in the creation of online content that a student can access at any time or in any place. The author concludes by proposing that digital editing and drawing applications that are free or low cost create the promise of democratizing the dissemination of content by allowing every instructor to become a content provider.
Sibling Interaction Effects
Authors: Boomsma Dorret I.
Published: March 2015

Children often grow up in the company of siblings, with whom they are genetically related. In this situation, the behavior of one sibling may influence the behavior of the other sibling. Assuming the heritability of the behavior of interest is greater than zero, such sibling interaction will render the “environment” of one child predictable from the genotypes of his or her siblings. In cross‐sectional data, detection of sibling interactions is based on the comparison of variances and covariances of siblings reared in different densities (e.g., twins and singletons) or of siblings of different degrees of genetic relatedness (e.g., mono‐ and dizygotic twins). For instance, in the classical
twin design
, a difference in phenotypic variance between mono‐ and dizygotic twins and a pattern of twin correlations, inconsistent with additive genetic influences, are indicative of sibling interaction. In longitudinal designs, sibling interactions can be modeled by means of phenotype to environment transmission, where the phenotype of one sibling at time
t
influences the environment of the second sibling at
t
 + 1.
Joint Action Models
Authors: Piegorsch Walter W.
Published: March 2015

One of the simplest forms of data is the dichotomous indication of whether or not a specific event occurs, categorized as “responses” and “nonresponses,” respectively. In some settings, there may be two classification schemes or qualitative factorizations examined for their mutual effect on the response. Alternatively, the differential response of two or more populations with respect to a single classification variable may be of interest. This article presents some basic models and methods for assessing the joint action in such dual‐factor studies with dichotomous data.
Stochastic Simulation of Rare Events
Authors: Gatto Riccardo
Published: March 2015

Stochastic simulation is an important and practical technique for computing probabilities of rare events, like the payoff probability of a financial option, the probability that a queue exceeds a certain level, or the probability of ruin of the insurer's risk process. Rare events occur so infrequently, that they cannot be reasonably recorded during a standard simulation procedure: specific simulation algorithms that thwart the rarity of the event to simulate are required. An important algorithm in this context is based on changing the sampling distribution and it is calledimportance sampling. Optimal Monte Carlo algorithms for computing rare event probabilities are either logarithmic efficient or possess bounded relative error.
Fabrication of antibacterial silver nanoparticle‐modified chitosan fibers using Eucalyptus extract as a reducing agent
Authors: Arvand Mansoor , Mirzaei Esmaeil , Derakhshan Mohammad Ali , Kharrazi Sharmin , Sadroddiny Esmaeil , Babapour Mahmoud , Faridi‐Majidi Reza
Published: March 2015

Green chemical method could be a promising route to achieve large scale synthesis of nanostructures for biomedical applications. Here, we describe a green chemical synthesis of silver nanoparticles (Ag NPs) on chitosan‐based electrospun nanofibers using Eucalyptus leaf extract. A series of silver salt (AgNO3) amounts were added to a certain composition of chitosan/polyethylene oxide aqueous acetic acid solution. The solutions were then electrospun to obtain nanofibrous mats and then, morphology and size of nanofibers were analyzed by scanning electron microscopy (SEM). Incubation of AgNO3‐containing mats into Eucalyptus leaf extract led to the formation of Ag NP clusters with average diameter of 91 ± 24 nm, depicted by SEM and transmission electron microscopy. Surface enhanced Raman spectroscopy also confirmed formation of Ag NPs on the nanofibers. The mats also showed antimicrobial activity against Escherichia coli and Staphylococcus aureus bacteria with bigger inhibition zone for extract‐exposed mats against S. aureus. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42133.
Evaluation of the efficiency of copolymers of methyl methacrylate and vinyl acetate synthesized by emulsion polymerization for control of aqueous filtrate loss
Authors: Nunes Rita de Cassia P. , Pires Renata V. , Lucas Elizabete F.
Published: March 2015

One of the main problems faced while drilling oil wells is loss of fluid to the rock formation. This loss can be reduced with the use of chemical additives called filtrate controllers, which must be tailored to the specific characteristics of the rock formation and drilling conditions. In this study, copolymers made of methyl methacrylate‐co‐vinyl acetate were synthesized by the emulsion polymerization technique, the most efficient technique to obtain copolymers with widely differing reactivity ratios. The products were characterized and evaluated for filtrate reduction efficiency, in the form of an emulsion and a polymer suspended in water. The filtrate reduction percentage, on the order of 80%, increased with higher concentration of vinyl acetate. The use of the polymer suspended in water caused only a slightly greater reduction in filtrate loss than that produced by the respective emulsion. However, other important advantages are associated with the suspended formulation: lower optimal concentration (∼ 8.5 g/mL), formation of extremely discrete filter cake particles and better logistical aspects, since in the case of emulsions, the volume of material that must be transported is much greater. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42191.
Microwave‐assisted chemical synthesis of conducting polyindole: Study of electrical property using Schottky junction
Authors: Tiwari Madhu , Kumar Ashish , Umre Harshit Sunil , Prakash Rajiv
Published: March 2015

A facile and rapid enhanced microwave‐assisted route for one‐pot synthesis has been developed to polymerize indole moiety using two different oxidizing agents for 60 s exposure at 30 ± 1°C. As‐synthesized conducting polyindoles, obtained by varying the synthesis process and oxidant, have been well characterized by various techniques. UV–vis, FT‐IR, and NMR have been used for their structural analysis while gel permeation chromatography, thermogravimetric analysis, and conductivity measurement to evaluate their enhanced properties and to perform a comparative study. Morphological texture of polyindole synthesized via different techniques has studied by scanning electron microscopy analysis. PIn synthesized by KIO3 (microwave synthesis) exhibit interconnecting texture which may be due to high level of supersaturation of solution under the influence of microwave irradiation. Thereafter, electrical property of spin‐coated thin film of polyindole is examined using four probe method and Al metal/semiconducting material Schottky junction. Microwave‐assisted polymer shows better performance for Schottky devices due to difference in charge transport, morphological texture, and distribution of Mn. The PIn synthesized via microwave irradiation with better charge transport across the metal/polymer interfaces shows the potential of this technique for synthesis of such polymers with enhanced electronic properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42192.
Object‐location memory in adults with autism spectrum disorder
Authors: Ring Melanie , Gaigg Sebastian B. , Bowler Dermot M.
Published: March 2015

This study tested implicit and explicit spatial relational memory in Autism Spectrum Disorder (ASD). Participants were asked to study pictures of rooms and pictures of daily objects for which locations were highlighted in the rooms. Participants were later tested for their memory of the object locations either by being asked to place objects back into their original locations or into new locations. Proportions of times when participants choose the previously studied locations for the objects irrespective of the instruction were used to derive indices of explicit and implicit memory [process‐dissociation procedure, Jacoby, 1991, 1998]. In addition, participants performed object and location recognition and source memory tasks where they were asked about which locations belonged to the objects and which objects to the locations. The data revealed difficulty for ASD individuals in actively retrieving object locations (explicit memory) but not in subconsciously remembering them (implicit memory). These difficulties cannot be explained by difficulties in memory for objects or locations per se (i.e., the difficulty pertains to object‐location relations). Together these observations lend further support to the idea that ASD is characterised by relatively circumscribed difficulties in relational rather than item‐specific memory processes and show that these difficulties extend to the domain of spatial information. They also lend further support to the idea that memory difficulties in ASD can be reduced when support is provided at test. Autism Res 2015, 8: 609–619. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.
Altered Cortical Thickness and Tract Integrity of the Mirror Neuron System and Associated Social Communication in Autism Spectrum Disorder
Authors: Chien Hsiang‐Yun , Gau Susan Shur‐Fen , Hsu Yung‐Chin , Chen Yu‐Jen , Lo Yu‐Chun , Shih Yao‐Chia , Tseng Wen‐Yih Isaac
Published: March 2015

Previous studies using neural activity recording and neuroimaging techniques have reported functional deficits in the mirror neuron system (MNS) for individuals with autism spectrum disorder (ASD). However, a few studies focusing on gray and white matter structures of the MNS have yielded inconsistent results. The current study recruited adolescents and young adults with ASD (aged 15–26 years) and age‐matched typically developing (TD) controls (aged 14–25 years). The cortical thickness (CT) and microstructural integrity of the tracts connecting the regions forming the classical MNS were investigated. High‐resolution T1‐weighted imaging and diffusion spectrum imaging were performed to quantify the CT and tract integrity, respectively. The structural covariance of the CT of the MNS regions revealed a weaker coordination of the MNS network in ASD. A strong correlation was found between the integrity of the right frontoparietal tracts and the social communication subscores measured by the Chinese version of the Social Communication Questionnaire. The results showed that there were no significant mean differences in the CTs and tract integrity between the ASD and TD groups, but revealed a moderate or even reverse age effect on the frontal MNS structures in ASD. In conclusion, aberrant structural coordination may be an underlying factor affecting the function of the MNS in ASD patients. The association between the right frontoparietal tracts and social communication performance implies a neural correlate of communication processing in the autistic brain. This study provides evidence of abnormal MNS structures and their influence on social communication in individuals with ASD. Autism Res 2015, 8: 694–708. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.
Rapid Linguistic Ambiguity Resolution in Young Children with Autism Spectrum Disorder: Eye Tracking Evidence for the Limits of Weak Central Coherence
Authors: Hahn Noemi , Snedeker Jesse , Rabagliati Hugh
Published: March 2015

Individuals with autism spectrum disorders (ASD) have often been reported to have difficulty integrating information into its broader context, which has motivated the Weak Central Coherence theory of ASD. In the linguistic domain, evidence for this difficulty comes from reports of impaired use of linguistic context to resolve ambiguous words. However, recent work has suggested that impaired use of linguistic context may not be characteristic of ASD, and is instead better explained by co‐occurring language impairments. Here, we provide a strong test of these claims, using the visual world eye tracking paradigm to examine the online mechanisms by which children with autism resolve linguistic ambiguity. To address concerns about both language impairments and compensatory strategies, we used a sample whose verbal skills were strong and whose average age (7; 6) was lower than previous work on lexical ambiguity resolution in ASD. Participants (40 with autism and 40 controls) heard sentences with ambiguous words in contexts that either strongly supported one reading or were consistent with both (John fed/saw the bat). We measured activation of the unintended meaning through implicit semantic priming of an associate (looks to a depicted baseball glove). Contrary to the predictions of weak central coherence, children with ASD, like controls, quickly used context to resolve ambiguity, selecting appropriate meanings within a second. We discuss how these results constrain the generality of weak central coherence. Autism Res 2015, 8: 717–726. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.
Sustainability Targets in Executive Remuneration: Targets, Time Frame, Country and Sector Specification
Authors: Maas Karen , Rosendaal Sanne
Published: March 2015

Existing remuneration plans for CEOs still mainly focus on financial performance and do not necessarily promote sustainable value creation for their firms. By way of reaction to this, a growing number of academics and practitioners are acknowledging the need for the inclusion of sustainability targets in executive remuneration. This study examines the current status of the use of sustainability targets in executive remuneration specified by country, sector and targets. Based on a sample of 490 listed firms from 11 countries and different sectors, the use of targets related to sustainability in executive remuneration is assessed. The targets are specified by kind of target (short term and long term) and content of target (environmental, social or a combination of both). The results of this study show that (a) in 2010 on average 33% of the firms used sustainability targets in remuneration, (b) mainly the ‘dirty’ industries use targets, (c) the targets used are mainly short‐term targets and (d) they focus on social issues. Copyright © 2015 John Wiley & Sons, Ltd and ERP Environment
Synthesis of a Fluorine‐Containing Cis‐Cisoidal One‐Handed Helical Polyphenylacetylene and Application of Highly Selective Photocyclic Aromatization Product on Oxygen Permselective Membrane
Authors: Zang Yu , Yin Guanwu , Aoki Toshiki , Teraguchi Masahiro , Kaneko Takashi , Ma Liqun , Jia Hongge
Published: March 2015

A novel phenylacetylene monomer having a perfluorinated alkyl group (M-F) was synthesized and polymerized in a chiral catalytic system to yield a one‐handed helical polymer. The ability and efficiency of the chiral induction of the fluorine‐containing monomer in the helix‐sense‐selective polymerization (HSSP) was much higher than those of a monomer having the corresponding alkyl group (M-H) we reported before. The resulting polymer P-F showed cis‐cisoidal one‐handed helical conformation, and was suitable for highly selective photocyclic aromatization (SCAT) to give a 2D surface modifier (T-F). Oxygen permselectivity through a base polymer membrane was highly enhanced from 1.83 to 2.36 by adding a small amount (1–5 wt%) of the 2D surface modifier T-F. The improvement was thought to be caused by improvement of solution selectivity on the membrane surface which the 2D surface modifier effectively covered. Chirality 27:459–463, 2015. © 2015 Wiley Periodicals, Inc.
Evaluation of the protective capabilities of nucleosome STRs obtained by large‐scale sequencing
Authors: Dong Chunnan , Yang Yadong , Yan Jiangwei , Fu Lihong , Zhang Xiaojing , Cong Bin , Li Shujin
Published: March 2015

Partial DNA profiles are often obtained from degraded forensic samples and are hard to analyze and interpret. With in‐depth studies on degraded DNA, an increasing number of forensic scientists have focused on the intrinsic structural properties of DNA. In theory, nucleosomes offer protection to the bound DNA by limiting access to enzymes. In our study, we performed large‐scale DNA sequencing on nucleosome core DNA of human leucocytes. Five nucleosome short tandem repeats (STRs) were selected (including three forensic common STRs (i.e. TPOX, TH01, and D10S1248) and two unpublished STRs (i.e. AC012568.7 and AC007160.3)). We performed a population genetic investigation and forensic genetic statistical analysis of these two unpublished loci on 108 healthy unrelated individuals of the HeBei Han population in China. We estimated the protective capabilities of five selected nucleosome loci and MiniFiler™ loci with artificial degraded DNA and case samples. We also analyzed differences between sequencing results and software predicted results. Our findings showed that nucleosome STRs were more likely to be detected than MiniFiler™ loci. They were well protected from degradation by nucleosomes and could be candidates for further nucleosome multiplex construction, which would increase the chances of obtaining a better balanced profile with fewer allelic drop‐outs.
Dismantling papillary renal cell carcinoma classification: The heterogeneity of genetic profiles suggests several independent diseases
Authors: Marsaud Alexandre , Dadone Bérengère , Ambrosetti Damien , Baudoin Christian , Chamorey Emmanuel , Rouleau Etienne , Lefol Cédrick , Roussel Jean‐François , Fabas Thibault , Cristofari Gaël , Carpentier Xavier , Michiels Jean‐François , Amiel Jean , Pedeutour Florence
Published: March 2015

Papillary renal cell carcinoma (pRCC) is the second most frequent renal cell carcinoma (RCC) after clear cell RCC. In contrast to clear cell RCC, there is no consensual protocol using targeted therapy for metastatic pRCC. Moreover, diagnosis of some pRCC, especially pRCC of type 2 (pRCC2) may be challenging. Our aim was to identify molecular biomarkers that could be helpful for the diagnosis and treatment of pRCC. We studied the clinical, histological, immunohistological, and comprehensive genetic features of a series of 31 pRCC including 15 pRCC1 and 16 pRCC2. We aimed to determine whether pRCC represents a unique entity or several diseases. In addition, we compared the genetic features of pRCC2 to those of eight RCC showing various degrees of tubulo‐papillary architecture, including three TFE‐translocation RCC and five unclassified RCC. We demonstrate that pRCC is a heterogeneous group of tumors with distinct evolution. While most pRCC2 had genetic profiles similar to pRCC1, some shared genomic features, such as loss of 3p and loss of chromosome 14, with clear cell RCC, TFE‐translocation RCC, and unclassified RCC. We identified variants of the MET gene in three pRCC1. A mutation in the BRAF gene was also identified in one pRCC1. In addition, using next‐generation sequencing (NGS), we identified several variant genes. Genomic profiling completed by NGS allowed us to classify pRCC2 in several groups and to identify novel mutations. Our findings provide novel information on the pathogenesis of pRCC that allow insights for personalized treatment. © 2015 Wiley Periodicals, Inc.
Thermal Analysis of Nanofluids on the Thin Film Evaporation of Meniscus
Authors: Chen Wei , Lin Jun
Published: March 2015

A mathematical model for predicting evaporation in the thin film region was developed and its analytical solutions were obtained for thin‐film thickness, the heat transport per unit length and the total heat flux transport in the thin‐film region. These analytical solutions show that the higher heat flux through the thin film region occurs due to the higher superheat. The maximum evaporative rate occurs when the effects of the increase in the temperature difference and in the thin film thickness on the heat flux q stay equal. A nanofluid, which is a colloidal mixture of nanoparticles (1 nm to 100 nm) and a base liquid (nanoparticle fluid suspensions), is employed as the working fluid. In a certain range, increasing the volume fraction of nanoparticles in the base fluid leads to decreasing the kinematic viscosity of the nanofluid and increasing the thermal conductivity, which influences the evaporation in the thin film region. The heat transfer rate per unit length and the total heat flux in the thin film region display various characteristics among the different type of nanofluids due to the differences of the kinematic viscosity and the thermal conductivity.
Combined targeting of high‐mobility group box‐1 and interleukin‐8 to control micrometastasis potential in gastric cancer
Authors: Chung Hye Won , Jang Sunphil , Kim Hoguen , Lim Jong‐Baeck
Published: March 2015

Micrometastasis is the major cause of treatment failure in gastric cancer (GC). Because epithelial‐to‐mesenchymal transition (EMT) is considered to develop prior to macroscopic metastasis, EMT‐promoting factors may affect micrometastasis. This study aimed to evaluate the role of extracellular high‐mobility group box‐1 (HMGB1) in EMT and the treatment effect of combined targeting of HMGB1 and interleukin‐8 (IL‐8) at early‐stage GC progression through interrupting EMT promotion. Extracellular HMGB1 was induced by human recombinant HMGB1 and pCMV‐SPORT6‐HMGB1 plasmid transfection. EMT activation was evaluated by immunoblotting, immunofluorescence and immunohistochemistry. Increased migration/invasion activities were evaluated by in vitro transwell migration/invasion assay using all histological types of human GC cell lines (N87, MKN28 SNU‐1 and KATOIII), N87‐xenograft BALB/c nude mice and human paired serum‐tissue GC samples. HMGB1‐induced soluble factors were measured by chemiluminescent immunoassay. Inhibition effects of tumor growth and EMT activation by combined targeting of HMGB1 and IL‐8 were evaluated in N87‐xenograft nude mice. Serum HMGB1 increases along the GC carcinogenesis and reaches maximum before macroscopic metastasis. Overexpressed extracellular HMGB1 promoted EMT activation and increased cell motility/invasiveness through ligation to receptor for advanced glycation end products. HMGB1‐induced IL‐8 overexpression contributed the HMGB1‐induced EMT in GC in vitro and in vivo. Blocking HMGB1 caused significant reduction of tumor growth, and addition of human recombinant IL‐8 rescues this antitumor effects. Our results imply the role of HMGB1 in EMT through IL‐8 mediation, and a potential mechanism of GC micrometastasis. Our observations suggest combination strategy of HMGB1 and IL‐8 as a promising diagnostic and therapeutic target to control GC micrometastasis.
Functional evidence of paraventricular nucleus involvement in cardiovascular and autonomic modulation in response to acute microgravity (head‐down tilt) in unanesthetized rats
Authors: Amorim Eric Diego Turossi , Peras Vivian Rossi , de Andrade Ozahyr , Martins‐Pinge Marli Cardoso
Published: March 2015

Exposure to microgravity induces autonomic and vestibular disorders such as alterations in cardiovascular function. The paraventricular nucleus of the hypothalamus (PVN) is known to be an important center for integrating autonomic and cardiovascular responses as blood volume reflexes. The acute effects promoted by microgravity and PVN involvement in cardiovascular and autonomic parameters have not yet been evaluated. Male Wistar rats were anesthetized to facilitate cannulae implantation in the PVN. After 3 days of surgical recovery, femoral artery and vein catheters were implanted for direct recording of blood pressure and heart rate (HR) in conscious animals to evaluate cardiovascular and autonomic changes in an acute protocol of head‐down tilt (HDT) in nonanesthetized rats. During HDT, there was an increase in mean arterial pressure (11 ± 1 mmHg, P < 0.05) and a decrease in HR (−28 ± 5 bpm, P < 0.05). Spectral analysis of systolic arterial pressure showed an increase in the low‐frequency (LF) component. In addition, HDT induced a reduction in the LF component and an increase in the high‐frequency (HF) component of the pulse interval (PI). PVN inhibition with muscimol reversed bradycardia and blocked the reduction of the LF and HF increases in PI during HDT. These results suggest that the PVN participates in the cardiovascular compensation during HDT, especially modulating cardiac responses. © 2015 Wiley Periodicals, Inc.
T1ρ imaging in premanifest Huntington disease reveals changes associated with disease progression
Authors: Wassef Shafik N. , Wemmie John , Johnson Casey P. , Johnson Hans , Paulsen Jane S. , Long Jeffrey D. , Magnotta Vincent A.
Published: March 2015

Background

Imaging biomarkers sensitive to Huntington's disease (HD) during the premanifest phase preceding motor diagnosis may accelerate identification and evaluation of potential therapies. For this purpose, quantitative MRI sensitive to tissue microstructure and metabolism may hold great potential. We investigated the potential value of T1ρ relaxation to detect pathological changes in premanifest HD (preHD) relative to other quantitative relaxation parameters.

Methods

Quantitative MR parametric mapping was used to assess differences between 50 preHD subjects and 26 age‐ and sex‐matched controls. Subjects with preHD were classified into two progression groups based on their CAG‐age product (CAP) score; a high and a low/moderate CAP group. Voxel‐wise and region‐of‐interest analyses were used to assess changes in the quantitative relaxation times.

Results

T1ρ showed a significant increase in the relaxation times in the high‐CAP group, as compared to controls, largely in the striatum. The T1ρ changes in the preHD subjects showed a significant relationship with CAP score. No significant changes in T2 or T2* relaxation times were found in the striatum. T2* relaxation changes were found in the globus pallidus, but no significant changes with disease progression were found.

Conclusion

These data suggest that quantitative T1ρ mapping may provide a useful marker for assessing disease progression in HD. The absence of T2 changes suggests that the T1ρ abnormalities are unlikely owing to altered water content or tissue structure. The established sensitivity of T1ρ to pH and glucose suggests that these factors are altered in HD perhaps owing to abnormal mitochondrial function. © 2015 International Parkinson and Movement Disorder Society
Coil combination for receive array spectroscopy: Are data‐driven methods superior to methods using computed field maps?
Authors: Rodgers Christopher T. , Robson Matthew D.
Published: March 2015

Purpose

Combining spectra from receive arrays, particularly X‐nuclear spectra with low signal‐to‐noise ratios (SNRs), is challenging. We test whether data‐driven combination methods are better than using computed coil sensitivities.

Theory

Several combination algorithms are recast into the notation of Roemer's classic formula, showing that they differ primarily in their estimation of coil receive sensitivities. This viewpoint reveals two extensions of the whitened singular‐value decomposition (WSVD) algorithm, using temporal or temporal + spatial apodization to improve the coil sensitivities, and thus the combined spectral SNR.

Methods

Radiofrequency fields from an array were simulated and used to make synthetic spectra. These were combined with 10 algorithms. The combined spectra were then assessed in terms of their SNR. Validation used phantoms and cardiac 31P spectra from five subjects at 3T.

Results

Combined spectral SNRs from simulations, phantoms, and humans showed the same trends. In phantoms, the combined SNR using computed coil sensitivities was lower than with WSVD combination whenever the WSVD SNR was >14 (or >11 with temporal apodization, or >9 with temporal + spatial apodization). These new apodized WSVD methods gave higher SNRs than other data‐driven methods.

Conclusion

In the human torso, at frequencies ≥49 MHz, data‐driven combination is preferable to using computed coil sensitivities. Magn Reson, 2015. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Magn Reson Med 75:473–487, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.
Novel electrical conductive hybrid nanostructures based on PA 6/MWCNTCOOH electrospun nanofibers and anchored MWCNTCOOH
Authors: Santos João Paulo Ferreira , da Silva Aline Bruna , Sundararaj Uttandaraman , Bretas Rosario E.S.
Published: March 2015

Electrical conductive nanostructures made of nanofibers of poly (amide 6) (PA6) with carboxyl functionalized multiwall carbon nanotubes (MWCNTCOOH) and anchored MWCNTCOOH were produced. The nanotubes were surface activated with carboxyl groups, dispersed in formic acid and added to a formic acid solution of PA6. The mixture was electrospun by applying a voltage of 30 kV; afterwards, the nanofiber's mats were immersed in an aqueous dispersion of MWCNTCOOH containing a nonionic surfactant. The chemical structure, morphology, thermal stability, and electrical conductivity of the nanostructures were evaluated by UV spectroscopy, scanning (SEM), and transmission electron microscopy (TEM), thermal gravimetric analyses (TGA) and volumetric conductivity measurements. The efficiency of the functionalization was confirmed by the UV peaks in the range between 220 and 250 nm (corresponding to a carbonyl group conjugated with a carbon‐carbon double bond). SEM and TEM micrographs showed the pullout of the MWCNTCOOH from the nanofibers and the formation of a stable, percolated, and anchored MWCNTCOOH network on the nanofibers due to the anchoring of the MWCNTCOOH from the surfactant solution on the MWCNTCOOH of the nanofibers. The coated nanostructures had higher thermal stability and higher electrical conductivity than the noncoated ones, showing the efficiency of this simple procedure. POLYM. ENG. SCI., 55:1263–1272, 2015. © 2015 Society of Plastics Engineers
Synthesis of polyacrylonitrile mediated by manganese(III) acetylacetonate (Mn(acac)3) and 2‐cyanoprop‐2‐yl dithionaphthalenoate
Authors: Xu Yuanyuan , Sun Jinming , Chen Hou , Bai Liangjiu , Tao Qian , Yu Lili , Wang Yating
Published: March 2015

2‐Cyanoprop‐2‐yl dithionaphthalenoate (CPDN) was successfully used as the chain transfer agent to prepare polyacrylonitrile in combination with manganese(III) acetylacetonate (Mn(acac)3) as the initiator. The novel polymerization exhibited well “living”/controlled characteristics. The polymerization behavior was revealed to comply with features of reversible addition–fragmentation chain transfer polymerization process. Mn(acac)3 played a key role as the initiator rather than the radical trapping agent in polymerization and exhibited better control performance than azo‐initiator. The narrowest molecular weight distribution was 1.31 under the condition of [AN]0:[Mn(acac)3]0:[CPDN]0 = 200:1:0.025 and AN:DMF = 1:1 (V/V). Various feed ratios of Mn(acac)3 and CPDN were also investigated in detail. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1305–1309
Synthesis, characterization, and photovoltaic properties of dithienylbenzobisazole‐dithienylsilole copolymers
Authors: Bhuwalka Achala , Ewan Monique D. , Mike Jared F. , Elshobaki Moneim , Kobilka Brandon , Chaudhary Sumit , Jeffries‐EL Malika
Published: March 2015

Three conjugated polymers comprised of dioctyl‐dithieno‐[2,3‐b:2',3'‐d]silole and a donor‐acceptor‐donor triad of either cis‐benzbisoxazole, trans‐benzobisoxazole or trans‐benzobisthiazole were synthesized via the Stille cross‐coupling reaction. The impact of varying the heteroatoms and/or the location within the benzobisazole moiety on the optical and electronic properties of the resulting polymers was evaluated via cyclic voltammetry and UV‐Visible spectroscopy. All of the polymers have similar optical band‐gaps of ∼1.9 eV and highest occupied molecular orbital levels of −5.2 eV. However, the lowest unoccupied molecular orbitals (LUMO) ranged from −3.0 to −3.2 eV. Interestingly, when the polymers were used as donor materials in bulk‐heterojunction photovoltaic cells with PC71BM as the electron‐acceptor, the benzobisoxazole‐based polymers gave slightly better results than the benzobisthiazole‐containing polymers with power conversion efficiencies up to 3.5%. These results indicate that benzobisoxazoles are promising materials for use in OPVs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1533–1540
Habitat Suitability Criteria via Parametric Distributions: Estimation, Model Selection and Uncertainty
Authors: Som Nicholas A. , Goodman Damon H. , Perry Russell W. , Hardy Thomas B.
Published: March 2015

Previous methods for constructing univariate habitat suitability criteria (HSC) curves have ranged from professional judgement to kernel‐smoothed density functions or combinations thereof. We present a new method of generating HSC curves that applies probability density functions as the mathematical representation of the curves. Compared with previous approaches, benefits of our method include (1) estimation of probability density function parameters directly from raw data, (2) quantitative methods for selecting among several candidate probability density functions, and (3) concise methods for expressing estimation uncertainty in the HSC curves. We demonstrate our method with a thorough example using data collected on the depth of water used by juvenile Chinook salmon (Oncorhynchus tschawytscha) in the Klamath River of northern California and southern Oregon. All R code needed to implement our example is provided in the appendix. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
Laparoscopic Colorectal Cancer Resection in High‐Volume Surgical Centers: Long‐Term Outcomes from the LAPCOLON Group Trial
Authors: Huscher Cristiano G. S. , Bretagnol Frederic , Corcione Francesco
Published: March 2015

Background

Strong evidence has confirmed the benefit of laparoscopy in colorectal cancer resection but remains a challenging procedure. It is not clear that such promising results in selected patients translate into a favorable risk–benefit balance in real practice. We conducted a multicenter national observational registry to assess operative and oncologic long‐term outcomes following laparoscopic colorectal cancer resection.

Methods

All patients with laparoscopic colorectal cancer resection between 2001 and 2004 were included. Data were extracted from the prospective Italian national database of 10 high‐volume centers (≥40 colorectal cancer laparoscopic resections per year). Surgical technique and follow‐up were standardized. Survivals were analyzed by Kaplan–Meier method.

Results

We reported 1832 patients with colon (58.5 %) and rectal cancer (41.5 %). TNM stage was 0–I–II in 1044 patients (57 %) and III–IV in 788 patients (43 %). Surgery included a totally laparoscopic procedure in 1820 patients (99.3 %). Conversion was 10.5 %. Postoperative morbidity and 30‐day mortality rates were 17 and 1.2 %, respectively. Clinical anastomotic leakage rate was 8.3 % (n = 152). R0 resection was 95 %. With a median follow‐up of 54.2 months, cancer recurrence rate was 13.3 %. At 5 years, cancer‐free survival was 86.7 %. Upon multivariate analysis, age (P = 0.001) and TNM stage (P < 0.001) were associated with cancer‐free survival. Predictive factors of cancer recurrence were gender (P = 0.029) and TNM stage (P < 0.001).

Conclusions

In high‐volume centers and non‐selective patients, laparoscopic colorectal resection for cancer achieves good operative results with satisfactory long‐term oncologic results. Even in the laparoscopy era, age, gender, and TNM stage remain the most powerful predictor of oncologic outcomes.
Response of the plant community and soil water status to alpine Kobresia meadow degradation gradients on the Qinghai–Tibetan Plateau, China
Authors: Li Jing , Zhang Fawei , Lin Li , Li Hongqin , Du Yangong , Li Yikang , Cao Guangmin
Published: March 2015

Degradation of alpine Kobresia meadow in the Qinghai–Tibetan Plateau is a serious problem, but its effect on the plant community and soil water status is not fully understood. We chose four homogeneous sites with <20, 20–70, 70–90, and >90 % absolute abundance of palatable grasses, and classified them as degradation gradient categories of poor, fair, good, and excellent, respectively. The lowest aboveground biomass and infiltration rate, and the highest root biomass, thickness of mattic epipedon, topsoil (<10 cm) organic matter content and volumetric ratio of root/soil all occurred in fair plots. There was little fluctuation in plant community diversity and topsoil bulk density among the degradation gradients. Results of non‐metric multidimensional scaling suggested that vegetation dynamics along degradation processes were non‐equilibrium in the alpine Kobresia meadow. The effects of degradation on soil water content and retention were the highest in the top layer (>10 cm). The minimum topsoil water content and maximum topsoil water retention both occurred in fair plots, indicating asynchrony between soil water content and holding capacity along degradation gradients, which likely resulted in a non‐equilibrium plant community pattern through physiological desiccation and nutrient deficits. Our findings should be highly informative for threshold‐based management of the degraded alpine Kobresia meadow in the future.