bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of partial shape memory effect of polymers by multicycle tests
Authors: Abdallah‐Elhirtsi Sofiane , Fitoussi Joseph , Rashmi Baralu‐Jagannatha , Prashantha Kalappa , Farzaneh Sedigheh , Lacrampe Marie‐France , Krawczak Patricia , Tcharkhtchi Abbas
Published: April 2015

In this work, an experimental investigation on a partial shape memory polymer (PSMP) which is transformed into shape memory material is presented. Multicycle shape memory tests are performed on thermoplastic polyurethane (TPU) at 70°C. At the end of each cycle, the capacity of the shape memory material increases. At the end of the first cycle, the recovery rate of TPU is only 67%; this partial shape memory effect (PSME) has been improved by successive cycles of shape memory tests. After the fourth cycle, it becomes nearly 100% shape memory material. The results of the fifth and sixth cycles confirm this modification. These original results indicate that a polymer with partial shape memory may be transformed into an SMP without any chemical modification. This increase of SME could be related to the creation of residual stresses during the tensile tests. The residual stresses are the origin of the driving force responsible for SME. POLYM. COMPOS., 36:1145–1151, 2015. © 2015 Society of Plastics Engineers
A functional SNP in MIR124-1, a brain expressed miRNA gene, is associated with aggressiveness in a Colombian sample
Authors: González-Giraldo Y. , Camargo A. , López-León S. , Adan A. , Forero D.A.
Published: April 2015

Background:

Interpersonal violence and suicide are among the main causes of mortality and morbidity around the world. In several developing countries, such as Colombia, they are among the first five entities of public health concern. Aggressiveness is an important endophenotype for aggression and suicidal behavior, having a heritability of around 50%. Exploration of classical candidate genes, involved in serotoninergic and dopaminergic neurotransmission, has identified few consistent risk factors for aggressiveness. miRNAs are a novel class of molecules with a growing role in normal neural function and neuropsychiatric disorders; of special interest, miR-124 is a brain-specific miRNA that is key for neuronal plasticity. We evaluated the hypothesis that a functional polymorphism in MIR124-1 gene might be associated with aggressiveness in a Colombian sample.

Methods:

The Spanish adaptation of the refined version of the Aggression Questionnaire and the abbreviated Barratt Impulsiveness Scale were applied to 170 young subjects. The functional SNP in MIR124-1 (rs531564) was genotyped by a TaqMan assay.

Results:

We found a significant association between the MIR124-1 and aggressiveness in our sample, with G/G carriers having lower scores (P = 0.01). This association seemed to be specific for aggressiveness, as it was not significant for impulsiveness.

Conclusions:

We showed for the first time the association of a functional polymorphism in MIR124-1 and aggressiveness. Known targets of miR-124 (such as BDNF and DRD4 genes) could explain the effect of this miRNA on behavior. A future analysis of additional novel functional polymorphisms in other brain expressed miRNAs could be useful for a deeper understanding of aggression in humans.
Failure to deactivate medial prefrontal cortex in people at high risk for psychosis
Authors: Falkenberg I. , Chaddock C. , Murray R.M. , McDonald C. , Modinos G. , Bramon E. , Walshe M. , Broome M. , McGuire P. , Allen P.
Published: April 2015

Impaired working memory is a core feature of schizophrenia and is linked with altered engagement the lateral prefrontal cortex. Although altered PFC activation has been reported in people with increased risk of psychosis, at present it is not clear if this neurofunctional alteration differs between familial and clinical risk states and/or increases in line with the level of psychosis risk. We addressed this issue by using functional MRI and a working memory paradigm to study familial and clinical high-risk groups. We recruited 17 subjects at ultra-high-risk (UHR) for psychosis, 10 non-affected siblings of patients with schizophrenia (familial high risk [FHR]) and 15 healthy controls. Subjects were scanned while performing the N-back working memory task. There was a relationship between the level of task-related deactivation in the medial PFC and precuneus and the level of psychosis risk, with deactivation weakest in the UHR group, greatest in healthy controls, and at an intermediate level in the FHR group. In the high-risk groups, activation in the precuneus was associated with the level of negative symptoms. These data suggest that increased vulnerability to psychosis is associated with a failure to deactivate in the medial PFC and precuneus during a working memory task, and appears to be most evident in subjects at clinical, as opposed to familial high risk.
Inositol transport proteins
Authors: Schneider Sabine
Published: April 2015

The cyclic polyol myo‐inositol is a key molecule in many different metabolic pathways among all organisms; in addition, it is fundamental for osmotic balance in the mammalian brain. This review sums up inositol transporters from eukaryotic organisms, elucidating their vital role in regulating the intracellular distribution and uptake of inositol. They can be divided into two groups according to their transport mechanisms: (1) sodium ion coupled inositol transporters that belong to the Solute Carrier Families 5 and 6‐like Superfamily and, (2) proton coupled inositol symporters that are members of the Major Facilitator Superfamily. Intriguingly members of both families offer promising targets for medical treatment of a variety of diseases.
A single PXXP motif in the C‐terminal region of srGAP3 mediates binding to multiple SH3 domains
Authors: Wuertenberger Silvia , Groemping Yvonne
Published: April 2015

The Slit‐Robo GTPase‐activating protein 3 (srGAP3) has been implicated in different critical aspects of neuronal development. These findings have mainly been based on the characterisation of the three conserved globular N‐terminal domains, while the function of the C‐terminal region (CTR) is still unknown. We show that this predicted unstructured region acts as an adaptor by binding to the endocytic proteins Amphiphysin, Endophilin‐A2, Endophilin‐A1, as well as the Ras signalling protein Grb2. All these interactions depend on a single proline‐rich motif in the CTR and the Src‐homology 3 domains of the binding partners. Via these interactions srGAP3 could link receptor signalling events to the endocytic machinery.
GGPPS deficiency aggravates CCl4‐induced liver injury by inducing hepatocyte apoptosis
Authors: Chen Wei-Bo , Lai Shan-Shan , Yu De-Cai , Liu Jia , Jiang Shan , Zhao Dan-Dan , Ding Yi-Tao , Li Chao-Jun , Xue Bin
Published: April 2015

GGPPS catalyses the expression of GGPP, a key protein in the mevalonate metabolic pathway. HMG‐CoA reductase inhibitor statins can induce liver injury by inhibiting GGPP. However, the function of GGPPS in liver injury has not yet been revealed. In this study, we found that GGPPS increased in liver injury and that GGPPS deletion augmented liver injury and fibrosis. GGPPS inhibition induced hepatocyte apoptosis, inflammation and TGF‐β1 secretion, which activated hepatic stellate cells. Our findings imply that GGPPS deletion induces hepatocyte apoptosis, which makes the liver vulnerable to hepatotoxicity.
Mining disease genes using integrated protein–protein interaction and gene–gene co‐regulation information
Authors: Li Jin , Wang Limei , Guo Maozu , Zhang Ruijie , Dai Qiguo , Liu Xiaoyan , Wang Chunyu , Teng Zhixia , Xuan Ping , Zhang Mingming
Published: April 2015

In humans, despite the rapid increase in disease‐associated gene discovery, a large proportion of disease‐associated genes are still unknown. Many network‐based approaches have been used to prioritize disease genes. Many networks, such as the protein–protein interaction (PPI), KEGG, and gene co‐expression networks, have been used. Expression quantitative trait loci (eQTLs) have been successfully applied for the determination of genes associated with several diseases. In this study, we constructed an eQTL‐based gene–gene co‐regulation network (GGCRN) and used it to mine for disease genes. We adopted the random walk with restart (RWR) algorithm to mine for genes associated with Alzheimer disease. Compared to the Human Protein Reference Database (HPRD) PPI network alone, the integrated HPRD PPI and GGCRN networks provided faster convergence and revealed new disease‐related genes. Therefore, using the RWR algorithm for integrated PPI and GGCRN is an effective method for disease‐associated gene mining.
Crystal structure of X‐prolyl aminopeptidase fromCaenorhabditis elegans: A cytosolic enzyme with a di‐nuclear active site
Authors: Iyer Shalini , La-Borde Penelope J. , Payne Karl A.P. , Parsons Mark R. , Turner Anthony J. , Isaac R. Elwyn , Acharya K. Ravi
Published: April 2015

Eukaryotic aminopeptidase P1 (APP1), also known as X‐prolyl aminopeptidase (XPNPEP1) in human tissues, is a cytosolic exopeptidase that preferentially removes amino acids from the N‐terminus of peptides possessing a penultimate N‐terminal proline residue. The enzyme has an important role in the catabolism of proline containing peptides since peptide bonds adjacent to the imino acid proline are resistant to cleavage by most peptidases. We show that recombinant and catalytically activeCaenorhabditis elegans APP‐1 is a dimer that uses dinuclear zinc at the active site and, for the first time, we provide structural information for a eukaryotic APP‐1 in complex with the inhibitor, apstatin. Our analysis reveals thatC. elegans APP‐1 shares similar mode of substrate binding and a common catalytic mechanism with other known X‐prolyl aminopeptidases.
Double‐blind randomized controlled trial comparing misoprostol and oxytocin for management of the third stage of labor in a Nigerian hospital
Authors: Musa Abdulkarim O. , Ijaiya Munir'deen A. , Saidu Rakiya , Aboyeji Abiodun P. , Jimoh Abiodun A. , Adesina Kikelomo T. , Abdul Ishaq F.
Published: April 2015

Objective

To compare the efficacy of oral misoprostol with that of oxytocin for active management of the third stage of labor (AMTSL).

Methods

A double‐blind randomized control trial was undertaken at a center in Ilorin, Nigeria, between January and June 2013. Every other eligible patient (in the first stage of labor at term, to have a spontaneous vaginal delivery, and no/low risk of postpartum hemorrhage [PPH]) were randomly assigned with computer‐generated random numbers to receive oral misoprostol (600 μg) plus placebo injection or oral placebo plus oxytocin injection (1 mL of 10 IU) in the third stage of labor. The primary outcome was amount of blood loss during delivery.

Results

Mean postpartum blood loss was 325.85 ± 164.72 mL in the 100 patients given misoprostol and 303.95 ± 163.33 mL in the 100 patients given oxytocin (P = 0.391). PPH (≥ 500 mL blood loss) was recorded in 15 (15.0%) patients given misoprostol and 14 (14.0%) given oxytocin (P = 0.841). Shivering, pyrexia, and diarrhea were all significantly more common in the misoprostol group (P < 0.01 for all).

Conclusion

The efficacy of oral misoprostol was similar to that of intramuscular oxytocin. Adverse effects associated with misoprostol were transient and self‐limiting. Thus, oral misoprostol is efficacious and a good alternative to oxytocin for AMTSL.

Pan African Clinical Trials Registry: PACTR201407000825227.
Predicting postoperative day 1 hematocrit levels after uncomplicated hysterectomy
Authors: Swenson Carolyn W. , Lanham Michael S. , Morgan Daniel M. , Berger Mitchell B.
Published: April 2015

Objective

To develop a model for predicting postoperative hematocrit levels after uncomplicated hysterectomy.

Methods

In a retrospective study, data were analyzed from the Michigan Surgery Quality Collaborative for non‐emergent hysterectomies performed for benign indications among women aged at least 18 years between January 1, 2012, and April 4, 2014. Linear mixed models were used for univariate and multivariate analyses.

Results

The model was developed with data from 4747 hysterectomies and validated on 1184 cases. In the mixed multivariate analysis, higher postoperative day 1 (POD1) hematocrit levels were associated with higher weight (B = 0.03222, P < 0.001), higher preoperative hematocrit (B = 0.6587, P < 0.001), and non‐vaginal hysterectomy (B = 0.2815, P = 0.0055). Lower POD1 hematocrit was associated with higher preoperative platelet count (B = − 0.00457, P < 0.001), greater estimated blood loss (B = − 0.00652, P < 0.001), and larger intraoperative crystalloid volume (B = − 0.3303, P < 0.001). The final model predicted POD1 hematocrit within 4% points of the actual value for 91.7% of cases in the validation set.

Conclusion

Use of the model after uncomplicated hysterectomy might help to support the practice of selectively conducting postoperative hematocrit tests after hysterectomy in a clinically thoughtful and cost‐effective manner.
Radiologic and clinical evaluation of children with first febrile urinary tract infection
Authors: Nickavar A. , Safaeian B. , abhari M. Biglari
Published: April 2015

Background and objectives:

Accurate diagnosis of acute pyelonephritis (APN) is clinically challenging in young children. The evaluation methods for APN and its major risk fac-tor, vesicoureteral reflux (VUR), have been revised in recent years. The aim of this study was to evaluate the value of different radiologic investigations in children experiencing the first episode of APN.

Materials and methods:

This study included 425 children of 2-12 months of age (17.5% male, 82.5% female) with APN. APN was defined as a positive urine culture associated with focal or diffuse decreased cortical uptake and preservation of renal contour indicated by DMSA renal scan.

Results:

The mean age at diagnosis was 39.2 ± 1.56 months. The following signs were observed in the patients: fever ≥ 38.5 °C, 66.8%; positive CRP, 85.4%; ESR > 25, 78.6%; and leukocytosis > 13,000/mm3, 53.4%.

Pyelocalyceal fullness and increased parenchymal echogenicity were the most common renal ultrasonography findings, and ultrasonography had 34% sensitivity and 53% specificity for these two findings. DMSA scan and ultrasound findings of APN were not significantly corre-lated (P = .112).

VUR was found in 42.2% of patients. DMSA scanning was not reliable for the diagnosis of VUR (P = .956), with 42% sensitivity and specificity.

VUR was identified in 42.7% of patients by ultrasound (P = .001), and the diagnostic rate was related to the VUR severity. Ultrasound had 42.7% sensitivity and 27% specificity for the diag-nosis of VUR.

Conclusion:

Determination of inflammatory markers is recommenced for the evaluation of chil-dren with APN. In addition, normal ultrasound is a valuable imaging tool for excluding high grade VUR.
Potent anti‐tumor response by targeting B cell maturation antigen (BCMA) in a mouse model of multiple myeloma
Authors: Oden Felix , Marino Stephen F. , Brand Janko , Scheu Susanne , Kriegel Cathleen , Olal Daniel , Takvorian Anna , Westermann Jörg , Yilmaz Buket , Hinz Michael , Daumke Oliver , Höpken Uta E. , Müller Gerd , Lipp Martin
Published: April 2015

Multiple myeloma (MM) is an aggressive incurable plasma cell malignancy with a median life expectancy of less than seven years. Antibody‐based therapies have demonstrated substantial clinical benefit for patients with hematological malignancies, particular in B cell Non‐Hodgkin's lymphoma. The lack of immunotherapies specifically targeting MM cells led us to develop a human‐mouse chimeric antibody directed against the B cell maturation antigen (BCMA), which is almost exclusively expressed on plasma cells and multiple myeloma cells. The high affinity antibody blocks the binding of the native ligands APRIL and BAFF to BCMA. This finding is rationalized by the high resolution crystal structure of the Fab fragment in complex with the extracellular domain of BCMA. Most importantly, the antibody effectively depletes MM cells in vitro and in vivo and substantially prolongs tumor‐free survival under therapeutic conditions in a xenograft mouse model. A BCMA‐antibody‐based therapy is therefore a promising option for the effective treatment of multiple myeloma and autoimmune diseases.
Gene expression profiling of sequential metastatic biopsies for biomarker discovery in breast cancer
Authors: Foukakis Theodoros , Lövrot John , Sandqvist Patricia , Xie Hanjing , Lindström Linda S. , Giorgetti Carla , Jacobsson Hans , Hedayati Elham , Bergh Jonas
Published: April 2015

The feasibility of longitudinal metastatic biopsies for gene expression profiling in breast cancer is unexplored. Dynamic changes in gene expression can potentially predict efficacy of targeted cancer drugs.

Patients enrolled in a phase III trial of metastatic breast cancer with docetaxel monotherapy versus combination of docetaxel + sunitinib were offered to participate in a translational substudy comprising longitudinal fine needle aspiration biopsies and Positron Emission Tomography imaging before (T1) and two weeks after start of treatment (T2). Aspirated tumor material was used for microarray analysis, and treatment‐induced changes (T2 versus T1) in gene expression and standardized uptake values (SUV) were investigated and correlated to clinical outcome measures.

Gene expression profiling yielded high‐quality data at both time points in 14/18 patients. Unsupervised clustering revealed specific patterns of changes caused by monotherapy vs. combination therapy (p = 0.021, Fisher's exact test). A therapy‐induced reduction of known proliferation and hypoxia metagene scores was prominent in the combination arm. Changes in a previously reported hypoxia metagene score were strongly correlated to the objective responses seen by conventional radiology assessments after 6 weeks in the combination arm, Spearman's ρ = 1 (p = 0.017) but not in monotherapy, ρ = −0.029 (p = 1). Similarly, the Predictor Analysis of Microarrays 50 (PAM50) proliferation metagene correlated to tumor changes merely in the combination arm at 6 and 12 weeks (ρ = 0.900, p = 0.083 and ρ = 1, p = 0.017 respectively). Reductions in mean SUV were a reliable early predictor of objective response in monotherapy, ρ = 0.833 (p = 0.008), but not in the combination arm ρ = −0.029 (p = 1).

Gene expression profiling of longitudinal metastatic aspiration biopsies was feasible, demonstrated biological validity and provided predictive information.
Impact of Organized Sports on Activity, Participation, and Quality of Life in People With Neurologic Disabilities
Authors: Sahlin K. Barbara , Lexell Jan
Published: April 2015

Physical activity and exercise is the mainstay of chronic disease prevention and health maintenance for all people with and without a disability, and clear evidence exists of the benefits among various populations with neurologic disabilities. However, the potential benefits of organized sports for people with neurologic disabilities are not as well explored. In this narrative review, current evidence regarding the impact of organized sports on activity, participation, and quality of life in people with neurologic disabilities of all ages is summarized, and facilitators of and barriers to participation in sports for this population are discussed. The articles reviewed were divided into 2 sets: (1) children and adolescents and (2) adults. The subjects of almost all of the studies were persons with a spinal cord injury. Children and adolescents with a disability who engaged in sports reported self‐concept scores close to those of able‐bodied athletes, as well as higher levels of physical activity. Adults with a spinal cord injury who engaged in organized sports reported decreased depression and anxiety, increased life satisfaction, and increased opportunity for gainful employment compared with nonathletic persons with disabilities. General facilitators, regardless of age, were fitness, fun, health, competence, and social aspects, whereas overall barriers were lack of or inappropriate medical advice and facilities, decreased self‐esteem, poor finances, dependency on others, and views held by others. The importance of this topic for further research is highlighted, and suggestions for future studies are proposed.
Clinical Experience With Continuous Intrathecal Baclofen Trials Prior to Pump Implantation
Authors: Phillips Mary Miller , Miljkovic Natasa , Ramos‐Lamboy Marlyn , Moossy John J. , Horton John , Buhari Alhaji M. , Munin Michael C.
Published: April 2015

Objective

To report our clinical experience using continuous intrathecal baclofen (ITB) trials prior to permanent pump implantation.

Design

Retrospective chart review.

Setting

An inpatient neurosurgery unit and outpatient physical medicine and rehabilitation clinics.

Participants

Fifty‐seven patients with refractory spasticity who underwent a continuous ITB trial during the years 2006‐2012.

Methods

Patients underwent placement of a temporary intrathecal catheter that was connected to an external pump. A successful trial was defined as a one‐level reduction in lower limb modified Ashworth scores in key spastic lower limb muscles identified for each individual patient. Subjective improvement in function or ease of performing functional tasks also were monitored.

Main Outcome Measures

Modified Ashworth scores, functional mobility in ambulatory patients only, and the incidence and severity of adverse events during the trial and up to 1 year after implantation.

Results

Spasticity significantly decreased during the trial. Average ambulation distance was unchanged, although 34% of ambulatory patients progressed to a less restrictive assistive device by trial completion. Adverse events (AEs) occurred in 26 patients. Minor AEs were seen in 18 patients, with the most common being nausea, transient urinary retention, and headache. Pumps were implanted in 86% of patients; 14% did not receive a pump because of AEs or because goals were not met. Six patients had their pump removed at 12 months for the following reasons: pump malfunctions (3), skin breakdown around the pump (1), infection (1), and expectations not met (1).

Conclusions

Continuous trials via an external catheter could be an option if patients and clinicians desire a comprehensive assessment of systemic and functional effects of ITB before pump implantation. The majority of AEs were minor and resolved spontaneously, and the most effective starting intrathecal dose was determined by pump insertion.
Zero lower bound, unconventional monetary policy and indicator properties of interest rate spreads
Authors: Hännikäinen Jari
Published: April 2015

This paper re‐examines the out‐of‐sample predictive power of interest rate spreads when the short‐term nominal rates have been stuck at the zero lower bound and the Fed has used unconventional monetary policy. Our results suggest that the predictive power of some interest rate spreads have changed since the beginning of this period. In particular, the term spread has been a useful leading indicator since December 2008, but not before that. Credit spreads generally perform poorly in the zero lower bound and unconventional monetary policy period. However, the mortgage spread has been a robust predictor of economic activity over the 2003–2014 period.
The wages of social responsibility — where are they? A critical review of ESG investing
Authors: Halbritter Gerhard , Dorfleitner Gregor
Published: April 2015

This paper contributes both to investigating the link between the corporate social and financial performance based on environmental, social and corporate governance (ESG) ratings and to reviewing the existing empirical evidence pertaining to this relationship. The sample used includes ESG data of ASSET4, Bloomberg and KLD for the U.S. market from 1991 to 2012. The econometrical framework applies an ESG portfolio approach using the Carhart (1997) four‐factor model as well as cross‐sectional Fama and MacBeth (1973) regressions. Previous empirical research indicates a relationship between ESG ratings and returns. As against this, the ESG portfolios do not state a significant return difference between companies with high and low ESG ratings. Although the Fama and MacBeth (1973) regressions reveal a significant influence of several ESG variables, investors are hardly able to exploit this relationship. The magnitude and direction of the impact are substantially dependent on the rating provider, the company sample and the particular subperiod. The results suggest that investors should no longer expect abnormal returns by trading a difference portfolio of high and low rated firms with regard to ESG aspects.
Interspecies communication in oral biofilm: An ocean of information
Authors: Parashar Amit , Parashar Shashi , Zingade Abhishek , Gupta Shikha , Sanikop Sheetal
Published: April 2015

The diversity of signalling opportunities within microbial communities, and the significant role of these molecules in coordinating gene expression and promoting biofilm formation, has provided the impetus to investigate the potential of inhibitory analogues to disrupt these networks, thereby providing mechanisms to control or influence the development of dental plaque. Within the oral biofilms, resident bacterial cells interact with one another and exchange messages in the form of signalling molecules and metabolites. In this review article, our aim is to elaborate the role of this quorum sensing and their involvement in pathogenesis to decipher information that can be useful to target pathways to control diseases.
Rotated infrared antenna transmitarray for the manipulation of circularly polarized wavefronts
Authors: He Yuchu , Eleftheriades George V.
Published: April 2015

An IR optical transmitarray is presented based on Antenna Array Sheet (AAS) for the manipulation of circularly polarized light. The unit cell of the transmitarray comprises three layers of metallic elliptical patches. Complete phase control is achieved through the local rotation of each unit cell. Thin refraction and focusing transmitarrays of this sort are demonstrated at infrared frequencies. Moreover, a new concept for realizing a polarization-discriminating device is introduced based on a flat refracting lens. These devices are compatible with current fabrication technology and can become crucial for the integration with other IR and nano-photonic devices.
Dipolar energies in Nd-Fe-B nanocrystalline magnets with and without Nd-Cu infiltration
Authors: Ohtori Hiroyuki , Iwano Kaoru , Mitsumata Chiharu , Yano Masao , Kato Akira , Shoji Tetsuya , Manabe Akira , Ono Kanta
Published: April 2015

We analyze the dipolar energies of Nd-Cu-infiltrated Nd-Fe-B nanocrystalline magnets during magnetization reversals by visualizing the magnetic dipolar interactions. Non-magnetic phases from the grains were identified by analyzing the element-specific magnetization distribution images taken with scanning transmission X-ray microscopy. The magnetic dipolar interactions were calculated from the interactions between the magnetization at each point and those at other points in the scanning transmission X-ray microscopy images. We present the dipolar energy distributions in Nd-Cu infiltrated nanocrystalline Nd-Fe-B magnets and compare them with those in nanocrystalline Nd-Fe-B magnets without Nd-Cu infiltration. The interplay between the exchange and dipolar interactions in Nd-Fe-B magnets is found to be essential for obtaining high coercivities.
Composition dependent structural organization in trihexyl(tetradecyl)phosphonium chloride ionic liquid-methanol mixtures
Authors: Gupta Aditya , Sharma Shobha , Kashyap Hemant K.
Published: April 2015

This article reports results from the molecular dynamics simulations on the structural arrangement of the ions and molecules in the mixtures of trihexyl(tetradecyl)phosphonium chloride ([P666,14+][Cl−]) ionic liquid (IL) and methanol (MeOH) over the entire composition range. Effects of composition on the charge and polarity orderings have been investigated via computation of X-ray scattering structure function, S(q), and by using a partitioning scheme proposed for such multi-component mixtures. Except for the neat methanol liquid, the total S(q) shows two peaks in its intermolecular region for all the mole-fractions. The lowest q peak is dominated primarily by anion-anion, cation-anion, and methanol-anion correlations. Our results signify that the methanol bulk structure, which predominantly has short-distance characteristic correlations and is governed by polar group of methanol, is retained for xIL ≤ 0.1. Then, the mixture goes through gradual structural changes from methanol-like to the IL-like for 0.1 < xIL ≤ 0.7. The dipolar interaction between methanol molecules weakens in this range, and the structural landscape of the mixture is steered by strong ion-ion, anion-methanol, and nonpolar interactions. The IL-like structural arrangement is virtually recovered for xIL > 0.7. At all the compositions studied, while the cation head groups are predominantly solvated by anions and subsequently by methanol molecules, the polar hydroxyl group of methanol is preferentially solvated by the anions. The radial distribution functions of selected pair of atomic species have also confirmed these observations.
On the magnetic reconnection of resistive tearing mode with the dynamic flow effects
Authors: Ali A. , Li Jiquan , Kishimoto Y.
Published: April 2015

Magnetic reconnection usually occurs in turbulent environments, which may not only provide anomalous resistivity to enhance reconnection rates but also significantly modify the reconnection process through direct nonlinear interaction with magnetic islands. This study presents numerical simulations investigating the effects of an imposed dynamic flow on magnetic reconnection, based on a two-dimensional reduced resistive MHD model. Results show that while the linear stability properties of the resistive tearing mode are moderately affected by the dynamic flow, nonlinear evolution is significantly modified by radial parity, amplitude, and frequency of the dynamic flow. After the slowly evolving nonlinear Rutherford stage, the reconnection process is found to progress in two phases by including the dynamic flow. A Sweet-Parker like current sheet is formed in the first phase. Afterwards, plasmoid instability is triggered in the second phase, where multiple plasmoids are continuously generated and ejected along the current sheet, leading to an impulsive bursty reconnection. The reconnection rate is considerably enhanced in the range of low resistivity as compared to without flow. We found that plasmoid instability onset and evolution are strongly influenced by the frequency and radial parity of the dynamic flows. The scaling of effective reconnection rates with the flow is found to be independent of resistivity.
Modeling the spectral responsivity of ultraviolet GaN Schottky barrier photodetectors under reverse bias
Authors: Atalla Mahmoud R. M. , Jiang Zhenyu , Liu Jie , Wang Li , Ashok S. , Xu Jian
Published: April 2015

The responsivity of GaN Schottky barrier photodetector (SBPD) as a function of incident wavelength and reverse bias has been studied theoretically. It was found that Schottky barrier (SB) lowering can explain the significant increase in the spectral responsivity as the reverse bias increases. The image force and the occupation of surface defects at the metal/semiconductor interface of the SBPD are the main factors for the SB lowering. The occupation of the surface defects was assumed to depend on the photogenerated current under reverse bias. The SB lowering causes a large leakage current that dominates the spectral responsivity at high reverse applied bias. The good agreement between the calculated and experimentally measured spectral responsivities suggests that the model is valid.
Electromagnetic-mechanical-thermal fully coupled model for Terfenol-D devices
Authors: Huang Wenmei , Deng Zhangxian , Dapino Marcelo J. , Weng Ling , Wang Bowen
Published: April 2015

This paper presents a fully coupled, nonlinear electromagnetic-mechanical-thermal model for Terfenol-D devices which include active magnetostrictive materials and passive components. The model includes two parts: (1) a material-level discrete energy-averaged model (DEAM) to describe the magnetomechanical coupling and thermal effect of Terfenol-D and (2) a system-level finite element model formulated in weak form using Maxwell's equations, Newton's law, and heat transfer equations. The objective is to describe the electromagnetic, mechanical, and thermal dynamics of the device. The system finite element model is constructed in COMSOL Multiphysics, and the nonlinear behavior of Terfenol-D is coupled through lookup tables generated by the DEAM. Preliminary results of the output capacity of a Terfenol-D actuator with respect to ambient temperature are presented in terms of blocked force, free displacement, and output power. The blocked force and free displacement decrease by 8.0% and 29.8%, respectively, for a 12 A (RMS) excitation current, as the temperature increases from 20 °C to 180 °C. One of the key contributions of this study is that it accounts for both the temperature-dependent Terfenol-D properties and the thermal effects of surrounding passive systems.
Dual cut-off direct current-tunable microwave low-pass filter on superconducting Nb microstrips with asymmetric nanogrooves
Authors: Dobrovolskiy Oleksandr V. , Huth Michael
Published: April 2015

We present a dual cut-off, dc-tunable low-pass microwave filter on a superconducting Nb microstrip with uniaxial asymmetric nanogrooves. The frequency response of the device was measured in the range 300 KHz–14 GHz at different temperatures, magnetic fields, and dc values. The microwave loss is most effectively reduced when the Abrikosov vortex lattice spatially matches the underlying washboard pinning landscape. The forward transmission coefficient S21(f) of the microstrip has a dc-tunable cut-off frequency fd which notably changes under dc bias reversal, due to the two different slope steepnesses of the pinning landscape. The device's operation principle relies upon a crossover from the weakly dissipative response of vortices at low frequencies when they are driven over the grooves, to the strongly dissipative response at high frequencies when the vortices are oscillating within one groove. The filter's cut-off frequency is the vortex depinning frequency tunable by the dc bias as it diminishes the pinning effect induced by the nanopattern. The reported results unveil an advanced microwave functionality of superconducting films with asymmetric (ratchet) pinning landscapes and are relevant for tuning the microwave loss in superconducting planar transmission lines.
External cavity quantum cascade lasers with ultra rapid acousto-optic tuning
Authors: Lyakh A. , Barron-Jimenez R. , Dunayevskiy I. , Go R. , Patel C. Kumar N.
Published: April 2015

We report operation of tunable external cavity quantum cascade lasers with emission wavelength controlled by an acousto-optic modulator (AOM). A long-wave infrared quantum cascade laser wavelength tuned from ∼8.5 μm to ∼9.8 μm when the AOM frequency was changed from ∼41MHz to ∼49 MHz. The laser delivered over 350 mW of average power at the center of the tuning curve in a linewidth of ∼4.7 cm−1. Measured wavelength switching time between any two wavelengths within the tuning range of the QCL was less than 1 μs. Spectral measurements of infrared absorption features of Freon demonstrated a capability of obtaining complete spectral data in less than 20 μs.
Dynamic properties of small-scale solar wind plasma fluctuations
Authors: Riazantseva M. O. , Budaev V. P. , Zelenyi L. M. , Zastenker G. N. , Pavlos G. P. , Safrankova J. , Nemecek Z. , Prech L. , Nemec F.
Published: April 2015

The paper presents the latest results of the studies of small-scale fluctuations in a turbulent flow of solar wind (SW) using measurements with extremely high temporal resolution (up to 0.03 s) of the bright monitor of SW (BMSW) plasma spectrometer operating on astrophysical SPECTR-R spacecraft at distances up to 350 000 km from the Earth. The spectra of SW ion flux fluctuations in the range of scales between 0.03 and 100 s are systematically analysed. The difference of slopes in low- and high-frequency parts of spectra and the frequency of the break point between these two characteristic slopes was analysed for different conditions in the SW. The statistical properties of the SW ion flux fluctuations were thoroughly analysed on scales less than 10 s. A high level of intermittency is demonstrated. The extended self-similarity of SW ion flux turbulent flow is constantly observed. The approximation of non-Gaussian probability distribution function of ion flux fluctuations by the Tsallis statistics shows the non-extensive character of SW fluctuations. Statistical characteristics of ion flux fluctuations are compared with the predictions of a log-Poisson model. The log-Poisson parametrization of the structure function scaling has shown that well-defined filament-like plasma structures are, as a rule, observed in the turbulent SW flows.
Incarceration and injection drug use in Baltimore, Maryland
Authors: Genberg Becky L. , Astemborski Jacquie , Vlahov David , Kirk Gregory D. , Mehta Shruti H.
Published: April 2015

Aims

There is limited longitudinal research examining incarceration and subsequent changes in drug use among people who inject drugs (PWID) in the United States. The objective of the current study was to characterize the frequency of incarceration and estimate the association between incarceration and subsequent injection drug use among current and former PWIDs in one US city.

Design

ALIVE (AIDS Linked to the Intravenous Experience) is a prospective cohort study of current and former PWIDs, with semi‐annual follow‐up occurring since 1988.

Setting

Baltimore, Maryland, USA.

Participants

A total of 3245 participants with 48 738 study visits were included. Participants enrolled from 1988 to 2012 with a median of 13 follow‐up visits per participant (Interquartile range = 7–25).

Measurements

Incarcerations were defined as any self‐reported jail or prison stays in the previous 6 months that were ≥7 days or longer. The primary outcome was defined as any self‐reported injection drug use in the previous 6 months.

Findings

At baseline, 29% were female, 90% African American and 33% HIV‐positive. Fifty‐seven per cent of participants experienced at least one incarceration episode. After adjusting for confounders, there was a positive association between incarceration and subsequent injection drug use [adjusted odds ratio (AOR) = 1.48, 95% confidence interval (CI) = 1.37–1.59]; however, stratified analysis showed that the effect was restricted to those who were not injecting at the time of incarceration (AOR = 2.11, 95% CI = 1.88–2.37).

Conclusions

In the United States, incarceration of people who had previously stopped injecting drugs appears to be associated with an increased risk of subsequent injecting.
HLA‐DQ allele‐restricted activation of nitroso sulfamethoxazole‐specific CD4‐positive T lymphocytes from patients with cystic fibrosis
Authors: Ogese M. O. , Saide K. , Faulkner L. , Whitaker P. , Peckham D. , Alfirevic A. , Baker D. M. , Sette A. , Pirmohamed M. , Park B. K. , Naisbitt D. J.
Published: April 2015

Background

For certain HLA allele‐associated drug hypersensitivity reactions, the parent drug has been shown to associate directly with the risk allele. In other forms of hypersensitivity, HLA risk alleles have not been identified and T cells are activated in an allele unrestricted manner. Chemically reactive drug metabolites bind to multiple proteins; thus, it is assumed that the derived peptide antigens interact with a number of HLA molecules to activate T cells; however, HLA restriction of the drug metabolite‐specific T‐cell response has not been studied.

Objective

To utilize T cells from sulfamethoxazole (SMX) hypersensitive patients with cystic fibrosis to examine the HLA molecules that interact with nitroso SMX (SMX‐NO)‐derived antigens.

Methods

T‐cell clones were generated from 4 hypersensitive patients. Drug‐specific proliferative responses and cytokine secretion were measured. Anti‐human class I and class II antibodies were used to analyse HLA restriction. Antigen‐presenting cells expressing different HLA molecules were used to determine the alleles involved in the presentation of SMX‐NO‐derived antigens to T cells.

Results

A total of 976 clones were tested for SMX‐NO reactivity. Thirty‐nine CD4+ clones were activated with SMX‐NO and found to proliferate and secrete cytokines. The SMX‐NO‐specific response was blocked with an antibody against HLA‐DQ. SMX‐NO‐specific responses were detected with antigen‐presenting cells expressing HLA‐DQB1*05:01 (patient 1) and HLA‐DQB1*02:01 (patient 2), but not other HLA‐DQB1 alleles.

Conclusion and Clinical Relevance

HLA‐DQ plays an important role in the activation of SMX‐NO‐specific CD4+ T cells. Detection of HLA‐DQ allele‐restricted responses suggests that T cells are activated by a limited repertoire of SMX‐NO‐modified peptides.
Analysis of signal processing in vestibular circuits with a novel light‐emitting diodes‐based fluorescence microscope
Authors: Direnberger Stephan , Banchi Roberto , Brosel Sonja , Seebacher Christian , Laimgruber Stefan , Uhl Rainer , Felmy Felix , Straka Hans , Kunz Lars
Published: April 2015

Optical visualization of neural network activity is limited by imaging system‐dependent technical tradeoffs. To overcome these constraints, we have developed a powerful low‐cost and flexible imaging system with high spectral variability and unique spatio‐temporal precision for simultaneous optical recording and manipulation of neural activity of large cell groups. The system comprises eight high‐power light‐emitting diodes, a camera with a large metal‐oxide‐semiconductor sensor and a high numerical aperture water‐dipping objective. It allows fast and precise control of excitation and simultaneous low noise imaging at high resolution. Adjustable apertures generated two independent areas of variable size and position for simultaneous optical activation and image capture. The experimental applicability of this system was explored in semi‐isolated preparations of larval axolotl (Ambystoma mexicanum) with intact inner ear organs and central nervous circuits. Cyclic galvanic stimulation of semicircular canals together with glutamate‐ and γ‐aminobutyric acid (GABA)‐uncaging caused a corresponding modulation of Ca2+ transients in central vestibular neurons. These experiments revealed specific cellular properties as well as synaptic interactions between excitatory and inhibitory inputs, responsible for spatio‐temporal‐specific sensory signal processing. Location‐specific GABA‐uncaging revealed a potent inhibitory shunt of vestibular nerve afferent input in the predominating population of tonic vestibular neurons, indicating a considerable impact of local and commissural inhibitory circuits on the processing of head/body motion‐related signals. The discovery of these previously unknown properties of vestibular computations demonstrates the merits of our novel microscope system for experimental applications in the field of neurobiology.
Inhibiting cholesterol degradation induces neuronal sclerosis and epileptic activity in mouse hippocampus
Authors: Chali Farah , Djelti Fathia , Eugene Emmanuel , Valderrama Mario , Marquer Catherine , Aubourg Patrick , Duykaerts Charles , Miles Richard , Cartier Nathalie , Navarro Vincent
Published: April 2015

Elevations in neuronal cholesterol have been associated with several degenerative diseases. An enhanced excitability and synchronous firing in surviving neurons are among the sequels of neuronal death in these diseases and also in some epileptic syndromes. Here, we attempted to increase neuronal cholesterol levels, using a short hairpinRNAto suppress expression of the enzyme cytochrome P450 family 46, subfamily A, polypeptide 1 gene (CYP46A1). This protein hydroxylates cholesterol and so facilitates transmembrane extrusion. A short hairpinRNA CYP46A1construction coupled to the adeno‐associated virus type 5 was injected focally and unilaterally into mouse hippocampus. It was selectively expressed first in neurons of the cornu ammonis (hippocampus) (CA)3a region. Cytoplasmic and membrane cholesterol increased, and the neuronal soma volume increased and then decreased before pyramidal cells died. AsCA3a pyramidal cells died, interictal electroencephalographic (EEG) events occurred during exploration and non‐rapid eye movement sleep. With time, neuronal death spread to involve pyramidal cells and interneurons of theCA1 region.CA1 neuronal death was correlated with a delayed local expression of phosphorylated tau. Astrocytes were activated throughout the hippocampus and microglial activation was specific to regions of neuronal death.CA1 neuronal death was correlated with distinct aberrantEEGactivity. During exploratory behaviour and rapid eye movement sleep,EEGoscillations at 7–10 Hz (theta) could accelerate to 14–21 Hz (beta) waves. They were accompanied by low‐amplitude, high‐frequency oscillations of peak power at ~300 Hz and a range of 250–350 Hz. Although episodes ofEEGacceleration were not correlated with changes in exploratory behaviour, they were followed in some animals by structured seizure‐like discharges. These data strengthen links between increased cholesterol, neuronal sclerosis and epileptic behaviour.
Modelling and mapping the distribution, diversity and abundance of freshwater mussels (Family Unionidae) in wadeable streams of Illinois, U.S.A.
Authors: Cao Yong , Stodola Alison , Douglass Sarah , Shasteen Diane , Cummings Kevin , Holtrop Ann
Published: April 2015

Freshwater mussels are one of the most imperilled animal groups in the world. Their effective conservation and restoration require a better understanding of their spatial distributions at a relevant scale and of their relationships with natural environmental factors and human disturbances.

In this study, we sampled over 900 sites on wadeable streams throughout Illinois, U.S.A., and compiled environmental data for a wide range of natural and anthropogenic factors related to climate, geology, land use, and connections to large rivers, dams and ponds.

Using random forest classification and regression, we modelled the presence–absence of mussels as a group (87% accuracy), the abundances of 29 individual mussel species (R2 = 0.2–0.51), species richness (R2 = 0.52) and total mussel abundance in a standard sample (R2 = 0.41).

The abundances of most species increased with stream size, the proportion of agricultural land in the catchment and the distance to the nearest dam or pond, but decreased with increasing catchment or channel slope and the proportion of forest in the catchment. Species varied in their relationships with climate variables, suggesting that they respond differently to climate change. Geology, particularly bedrock depth, was important for many species. Species richness and total mussel abundance responded positively to stream size and negatively to the slope of streams or catchments.

The models were applied to unsampled wadeable stream reaches to generate mussel distribution maps at the reach scale, useful tools for resource managers to effectively protect and restore mussel biodiversity. The models also improve our understanding of how mussel populations and assemblages are structured by natural factors and human disturbances at a broad scale.