bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling genetic reorganization in the mouse spinal cord affecting left–right coordination during locomotion
Authors: Rybak Ilya A. , Shevtsova Natalia A. , Kiehn Ole
Published: October 2013

Key points

EphA4, Netrin‐1 and DCC are axon guidance molecules involved in mid‐line crossing of axons of commissural and other spinal interneurons. Absence of these molecules in mice lead to specific locomotor pattern transformations.

We use a computational model of the bilateral spinal neural networks to simulate the genetically induced transformations in EphA4, Netrin‐1 and DCC mutant mice.

The model closely reproduces the changes in the locomotor patterns in these mutants, including transformations from the normal left–right alternating pattern to a synchronized hopping pattern in EphA4 and Netrin‐1 mutants, uncoordinated left–right activity in the DCC mutant, and re‐establishment of the alternating patterns in EphA4 and DCC mutant cords by augmentation of inhibitory interactions.

The model suggests mechanistic explanations for the locomotor transformations and provides insights into the organization of the locomotor network in the spinal cord.

Abstract  The spinal neural circuit contains inhibitory (CINi) and excitatory (CINe) commissural interneurons with axons crossing the mid‐line. Direction of these axons to the other side of the cord is controlled by axon guidance molecules, such as Netrin‐1 and DCC. The cord also contains glutamatergic interneurons, whose axon guidance involves the EphA4 receptor. In EphA4 knockout (KO) and Netrin‐1 KO mice, the normal left–right alternating pattern is replaced with a synchronized hopping gait, and the cord of DCC KO mice exhibits uncoordinated left and right oscillations. To investigate the effects of these genetic transformations, we used a computational model of the spinal circuits containing left and right rhythm‐generating neuron populations (RGs), each with a subpopulation of EphA4‐positive neurons, and CINi and CINe populations mediating mutual inhibition and excitation between the left and right RGs. In the EphA4 KO circuits, half of the EphA4‐positive axons crossed the mid‐line and excited the contralateral RG neurons. In the Netrin‐1 KO model, the number of contralateral CINi projections was significantly reduced, while in the DCC KO model, the numbers of both CINi and CINe connections were reduced. In our simulations, the EphA4 and Netrin‐1 KO circuits switched from the left–right alternating pattern to a synchronized hopping pattern, and the DCC KO network exhibited uncoordinated left–right activity. The amplification of inhibitory interactions re‐established an alternating pattern in the EphA4 and DCC KO circuits, but not in the Netrin‐1 KO network. The model reproduces the genetic transformations and provides insights into the organization of the spinal locomotor network.
Endogenous zinc depresses GABAergic transmission via T‐type Ca2+ channels and broadens the time window for integration of glutamatergic inputs in dentate granule cells
Authors: Grauert Antonia , Engel Dominique , Ruiz Arnaud J.
Published: October 2013

Key points

Zinc inhibits ionotropic receptors commonly found at central synapses, as well as a wide variety of voltage‐activated ion channels that modulate neuronal excitability and neurotransmitter release.

We found that zinc chelation facilitated GABAergic signalling in dentate granule cells and that blocking T‐type Ca2+ channel activity abolished this effect. Zinc chelation reduced spike threshold, increased spike width and shifted the input–output relationship in dentate interneurones, which is consistent with increased excitability.

In granule cells, zinc chelation narrowed the window for the integration of glutamatergic inputs originating from perforant path synapses.

These results demonstrate that zinc modulates dentate interneurone function and regulates spike routing to local and hippocampal targets.

Abstract  Zinc actions on synaptic transmission span the modulation of neurotransmitter receptors, transporters, activation of intracellular cascades and alterations in gene expression. Whether and how zinc affects inhibitory synaptic signalling in the dentate gyrus remains largely unexplored. We found that mono‐ and di‐synaptic GABAergic inputs onto dentate granule cells were reversibly depressed by exogenous zinc application and enhanced by zinc chelation. Blocking T‐type Ca2+ channels prevented the effect of zinc chelation. When recording from dentate fast‐spiking interneurones, zinc chelation facilitated T‐type Ca2+ currents, increased action potential half‐width and decreased spike threshold. It also increased the offset of the input–output relation in a manner consistent with enhanced excitability. In granule cells, chelation of zinc reduced the time window for the integration of glutamatergic inputs originating from perforant path synapses, resulting in reduced spike transfer. Thus, zinc‐mediated modulation of dentate interneurone excitability and GABA release regulates information flow to local targets and hippocampal networks.
Aeroperformance Measurements for a Fully Cooled High-Pressure Turbine Stage
Authors: Haldeman Charles , Dunn Michael , Mathison Randall , Troha William , Vander Hoek Timothy , Riahi Ardeshir
Published: September 2013

A detailed aero performance measurement program utilizing fully cooled engine hardware (high-pressure turbine stage) supplied by Honeywell Aerospace Advanced Technology Engines is described. The primary focus of this work was obtaining relevant aerodynamic data for a small turbine stage operating at a variety of conditions, including changes in operating conditions, geometry, and cooling parameters. The work extraction and the overall stage performance for each of these conditions can be determined using the measured acceleration rate of the turbine disk, the previously measured moment of inertia of the rotating system, and the mass flow through the turbine stage. Measurements were performed for two different values of tip/shroud clearance and two different blade tip configurations. The vane and blade cooling mass flow could be adjusted independently and set to any desired value, including totally off. A wide range of stage pressure ratios, coolant to free stream temperature ratios, and corrected speeds were used during the course of the investigation. A combustor emulator controlled the free stream inlet gas temperature, enabling variation of the temperature ratios and investigation of their effects on aero performance. The influence of the tip/shroud gap is clearly seen in this experiment. Improvements in specific work and efficiency achieved by reducing the tip/shroud clearance depend upon the specific values of stage pressure ratio and corrected speed. The maximum change of 3%–4% occurs at a stage pressure ratio and corrected speed greater than the initial design point intent. The specific work extraction and efficiency for two different blade tip sets (one damaged from a rub and one original) were compared in detail. In general, the tip damage only had a very small effect on the work extraction for comparable conditions. The specific work extraction and efficiency were influenced by the presence of cooling gas and by the temperature of the cooling gas relative to the free stream gas temperature and the metal temperature. These same parameters were influenced by the magnitude of the vane inlet gas total temperature relative to the vane metal temperature and the coolant gas temperature.
Density-Convex Model Based Robust Optimization to Key Components of Surgical Robot
Authors: Jiang Shan , Gao Xuesheng , Liu Jun , Yang Jun , Yu Yan
Published: October 2013

This paper investigates a new robust optimization framework based on density-convex reliability model and applies it to the dimensional optimization of magnetic resonance (MR) compatible surgical robot. As a justified tool for assessing reliability, the density-convex model is proposed on account of the reality that available data information is always insufficient. Based on the density-convex model, reliability functions of structure are constructed and taken as constraint conditions. The Euclidean norm of the sensitivity Jacobian matrix is selected as robust index and stated as the ultimate objective function. By using finite element method and artificial neural network (FEM–ANN) method, the explicit functions of mechanical response are achieved effectively. The optimization is solved by a gradient-based optimization algorithm in the framework. As an application of the above optimization framework, a prototype robot is designed and manufactured. Finally, a test experiment verifies the high reliability of the robot and further proves the validity and effectiveness of this proposed method.
Study of the Effect of Luminescence Down-Shifting on GaAs Solar Cells With Several Optical Windows Layers
Authors: Abderrezek Mahfoud , Fathi Mohamed , Djahli Farid , Ayad Mohammed
Published: October 2013

Luminescence down shifting (LDS) is an elegant approach used to improve the efficiency of single solar cells, in this approach, the photovoltaic (PV) glass material is replaced with a thin layer of polymer polymethyl methacrylate (PMMA) doped with optically active organic dyes. In this paper, we present a theoretical study. To assess the improvements introduced by LDS on an n-i-p-GaAs solar cells structure formed by diverse types of windows layers (Al0.8Ga0.2As, Al0.52In0.48P, and Ga0.5In0.5P). The performance of the solar cell is investigated as a function of organic dyes. It has been shown that the gain in power conversion efficiency attains values up to 5.79, 8.15, and 8.37% with Al0.8Ga0.2As, Al0.52In0.48P, and Ga0.5In0.5P in the standard spectrum AM1.5G, moreover, they increase the short circuit current density.
U.S. Carbon Plan Relies on Uncertain Capture Technology
Authors: Kintisch Eli
Published: September 2013

The Obama administration last week unveiled a landmark proposal that would require new coal-fired power plants to capture at least some of the carbon pollution they emit, but the needed technology remains uncertain.
Taming a Mercurial Element
Authors: Malakoff David
Published: September 2013

Can a landmark global agreement to curb mercury pollution make a difference?
Antiviral Skin Helpers
Authors: Ferrarelli Leslie K.
Published: October 2013

Secretion of a cytokine by T helper cells protects psoriatic lesions from viral infection.
Pharmacokinetic Interaction between Maraviroc and Fosamprenavir-Ritonavir: an Open-Label, Fixed-Sequence Study in Healthy Subjects
Authors: Vourvahis Manoli , Plotka Anna , Mendes da Costa Laure , Fang Annie , Heera Jayvant
Published: October 2013

This open-label, fixed-sequence, phase 1 study evaluated the pharmacokinetic interaction between maraviroc (MVC) and ritonavir-boosted fosamprenavir (FPV/r) in healthy subjects. In period 1, subjects received 300 mg of MVC twice daily (BID; cohort 1) or once daily (QD; cohort 2) for 5 days. In period 2, cohort 1 subjects received 700/100 mg of FPV/r BID alone on days 1 to 10 and then FPV/r at 700/100 mg BID plus MVC at 300 mg BID on days 11 to 20; cohort 2 subjects received FPV/r at 1,400/100 mg QD alone on days 1 to 10 and then FPV/r at 1,400/100 mg QD plus MVC at 300 mg QD on days 11 to 20. Pharmacokinetic parameters, assessed on day 5 of period 1 and on days 10 and 20 of period 2, included the maximum plasma concentration (Cmax), the concentration at end of dosing interval (Cτ), and the area under the curve over dosing interval (AUCτ). Safety and tolerability were also assessed. MVC geometric mean AUCτ,Cmax, andCτwere increased by 149, 52, and 374%, respectively, after BID dosing with FPV/r, and by 126, 45, and 80%, respectively, after QD dosing. Amprenavir (the active form of the prodrug fosamprenavir) and ritonavir exposures were decreased in the presence of MVC with amprenavir AUCτ,Cmax, andCτdecreased by 34 to 36% in the presence of FPV/r plus maraviroc BID and by 15 to 30% with FPV/r plus MVC QD both compared to FPV/r alone. The overall all-causality adverse-event (AE) incidence rate was 96.4%; all AEs were of mild or moderate severity. Commonly reported treatment-related AEs (>20% of patients overall) included diarrhea, fatigue, abdominal discomfort, headache, and nausea. No serious AEs or deaths occurred. In summary, maraviroc exposure increased in the presence of FPV/r, whereas MVC coadministration decreased amprenavir and ritonavir exposures. MVC dosed at 300 mg BID with FPV/r is not recommended due to concerns of lower amprenavir exposures; however, no dose adjustment is warranted with MVC at 150 mg BID in combination with FPV/r based on the available clinical data. MVC plus FPV/r was generally well tolerated; no new safety signals were detected.
Antibiotic-Induced Autoactivation of IS
256
in Staphylococcus aureus
Authors: Schreiber Franziska , Szekat Christiane , Josten Michaele , Sahl Hans-Georg , Bierbaum Gabriele
Published: October 2013

The 3′ end of
rsbU
, encoding the positive regulator of the stress factor sigma B, was identified as a hot spot for spontaneous IS
256
insertion in
Staphylococcus aureus
SA137/93G. Interestingly, subinhibitory concentrations of chloramphenicol in combination with heat stress, as well as linezolid and spectinomycin at physiological temperatures, selected for such
rsbU
::IS
256
insertion mutants. In consequence of the inactivation of
rsbU
, the IS
256
transposition frequency was increased 4-fold in
S. aureus
HG001.
Biochemical Analysis of the Role of G118R-Linked Dolutegravir Drug Resistance Substitutions in HIV-1 Integrase
Authors: Quashie Peter K. , Mesplède Thibault , Han Ying-Shan , Veres Tamar , Osman Nathan , Hassounah Said , Sloan Richard D. , Xu Hong-Tao , Wainberg Mark A.
Published: October 2013

Drug resistance mutations (DRMs) have been reported for all currently approved anti-HIV drugs, including the latest integrase strand transfer inhibitors (INSTIs). We previously used the new INSTI dolutegravir (DTG) to select a G118R integrase resistance substitution in tissue culture and also showed that secondary substitutions emerged at positions H51Y and E138K. Now, we have characterized the impact of the G118R substitution, alone or in combination with either H51Y or E138K, on 3′ processing and integrase strand transfer activity. The results show that G118R primarily impacted the strand transfer step of integration by diminishing the ability of integrase-long terminal repeat (LTR) complexes to bind target DNA. The addition of H51Y and E138K to G118R partially restored strand transfer activity by modulating the formation of integrase-LTR complexes through increasing LTR DNA affinity and total DNA binding, respectively. This unique mechanism, in which one function of HIV integrase partially compensates for the defect in another function, has not been previously reported. The G118R substitution resulted in low-level resistance to DTG, raltegravir (RAL), and elvitegravir (EVG). The addition of either of H51Y or E138K to G118R did not enhance resistance to DTG, RAL, or EVG. Homology modeling provided insight into the mechanism of resistance conferred by G118R as well as the effects of H51Y or E138K on enzyme activity. The G118R substitution therefore represents a potential avenue for resistance to DTG, similar to that previously described for the R263K substitution. For both pathways, secondary substitutions can lead to either diminished integrase activity and/or increased INSTI susceptibility.
Comparative Evaluation of PCR and Imprint Smear Microscopy Analyses of Skin Biopsy Specimens in Diagnosis of Macular, Papular, and Mixed Papulo-Nodular Lesions of Post-Kala-Azar Dermal Leishmaniasis
Authors: Verma Neena , Singh Dharmendra , Pandey Krishna , Das Vidya Nand Rabi , Lal Chandra Shekhar , Verma Rakesh Bihari , Sinha Prabhat Kumar , Das Pradeep
Published: September 2013

Diagnosis of post-kala-azar dermal leishmaniasis (PKDL), particularly the macular form, is difficult when based on microscopy. This study compared the results of nested PCR (91.9% positive samples) with imprint smear microscopy (70.9% positive samples) for 62 PKDL samples. We found that nested PCR, which indicated 87.5% positivity for the macular lesions, compared to 41.6% positivity by imprint smear microscopy, is an efficient method for early diagnosis of PKDL.
Molecular Characterization of Staphylococcus aureus and Influenza Virus Coinfections in Patients with Fatal Pneumonia
Authors: Denison Amy M. , DeLeon-Carnes Marlene , Blau Dianna M. , Shattuck Eric C. , McDougal Linda K. , Rasheed James K. , Limbago Brandi M. , Zaki Sherif R. , Paddock Christopher D.
Published: September 2013

Molecular techniques were used to characterize genetic features of
Staphylococcus aureus
in 66 fatal cases of pneumonia caused by
S. aureus
and influenza A or B viruses. Nucleic acids were extracted from formalin-fixed, paraffin-embedded tissues. The majority of cases revealed genetic markers for Panton-Valentine leukocidin,
mecA
, and
spa
type t008.
Genome Scale Evolution of Myxoma Virus Reveals Host-Pathogen Adaptation and Rapid Geographic Spread
Authors: Kerr Peter J. , Rogers Matthew B. , Fitch Adam , DePasse Jay V. , Cattadori Isabella M. , Twaddle Alan C. , Hudson Peter J. , Tscharke David C. , Read Andrew F. , Holmes Edward C. , Ghedin Elodie
Published: September 2013

The evolutionary interplay between myxoma virus (MYXV) and the European rabbit (Oryctolagus cuniculus) following release of the virus in Australia in 1950 as a biological control is a classic example of host-pathogen coevolution. We present a detailed genomic and phylogeographic analysis of 30 strains of MYXV, including the Australian progenitor strain Standard Laboratory Strain (SLS), 24 Australian viruses isolated from 1951 to 1999, and three isolates from the early radiation in Britain from 1954 and 1955. We show that in Australia MYXV has spread rapidly on a spatial scale, with multiple lineages cocirculating within individual localities, and that both highly virulent and attenuated viruses were still present in the field through the 1990s. In addition, the detection of closely related virus lineages at sites 1,000 km apart suggests that MYXV moves freely in geographic space, with mosquitoes, fleas, and rabbit migration all providing means of transport. Strikingly, despite multiple introductions, all modern viruses appear to be ultimately derived from the original introductions of SLS. The rapidity of MYXV evolution was also apparent at the genomic scale, with gene duplications documented in a number of viruses. Duplication of potential virulence genes may be important in increasing the expression of virulence proteins and provides the basis for the evolution of novel functions. Mutations leading to loss of open reading frames were surprisingly frequent and in some cases may explain attenuation, but no common mutations that correlated with virulence or attenuation were identified.
Tetherin Restricts Herpes Simplex Virus 1 and Is Antagonized by Glycoprotein M
Authors: Blondeau Caroline , Pelchen-Matthews Annegret , Mlcochova Petra , Marsh Mark , Milne Richard S. B. , Towers Greg J.
Published: September 2013

Tetherin is a broadly active antiviral effector that works by tethering nascent enveloped virions to a host cell membrane, thus preventing their release. In this study, we demonstrate that herpes simplex virus 1 (HSV-1) is targeted by tetherin. We identify the viral envelope glycoprotein M (gM) as having moderate anti-tetherin activity. We show that gM but not gB or gD efficiently removes tetherin from the plasma membrane and can functionally substitute for the human immunodeficiency virus type 1 (HIV-1) Vpu protein, the prototypic viral tetherin antagonist, in rescuing HIV-1 release from tetherin-expressing cells. Our data emphasize that tetherin is a broadly active antiviral effector and contribute to the emerging hypothesis that viruses must suppress or evade an array of host cell countermeasures in order to establish a productive infection.
Viroplasm Protein P9-1 of
Rice Black-Streaked Dwarf Virus
Preferentially Binds to Single-Stranded RNA in Its Octamer Form, and the Central Interior Structure Formed by This Octamer Constitutes the Major RNA Binding Site
Authors: Wu Jianyan , Li Jia , Mao Xiang , Wang Weiwu , Cheng Zhaobang , Zhou Yijun , Zhou Xueping , Tao Xiaorong
Published: September 2013

The P9-1 protein of
Rice black-streaked dwarf virus
(RBSDV) is an essential part of the viroplasm. However, little is known about its nature or biological function in the viroplasm. In this study, the structure and function of P9-1 were analyzed for
in vitro
binding to nucleic acids. We found that the P9-1 protein preferentially bound to single-stranded versus double-stranded nucleic acids; however, the protein displayed no preference for RBSDV versus non-RBSDV single-stranded ssRNA (ssRNA). A gel mobility shift assay revealed that the RNA gradually shifted as increasing amounts of P9-1 were added, suggesting that multiple subunits of P9-1 bind to ssRNA. By using discontinuous blue native gel and chromatography analysis, we found that the P9-1 protein was capable of forming dimers, tetramers, and octamers. Strikingly, we demonstrated that P9-1 preferentially bound to ssRNA in the octamer, rather than the dimer, form. Deletion of the C-terminal arm resulted in P9-1 no longer forming octamers; consequently, the deletion mutant protein bound to ssRNA with significantly lower affinity and with fewer copies bound per ssRNA. Alanine substitution analysis revealed that electropositive amino acids among residues 25 to 44 are important for RNA binding and map to the central interior structure that was formed only by P9-1 octamers. Collectively, our findings provide novel insights into the structure and function of RBSDV viroplasm protein P9-1 binding to RNA.
Comprehensive Mapping and Analysis of Kaposi's Sarcoma-Associated Herpesvirus 3′ UTRs Identify Differential Posttranscriptional Control of Gene Expression in Lytic versus Latent Infection
Authors: McClure Lydia V. , Kincaid Rodney P. , Burke James M. , Grundhoff Adam , Sullivan Christopher S.
Published: September 2013

3′ untranslated regions (UTRs) are known to play an important role in posttranscriptional regulation of gene expression. Here we map the 3′ UTRs of Kaposi's sarcoma-associated herpesvirus (KSHV) using next-generation RNA sequencing, 3′ rapid amplification of cDNA ends (RACE), and tiled microarray analyses. Chimeric reporters containing the KSHV 3′ UTRs show a general trend toward reduced gene expression under conditions of latent infection. Those 3′ UTRs with a higher GC content are more likely to be associated with reduced gene expression. KSHV transcripts display an extensive use of shared polyadenylation sites allowing for partially overlapping 3′ UTRs and regulatory activities. In addition, a subset of KSHV 3′ UTRs is sufficient to convey increased gene expression under conditions of lytic infection. These results suggest a role for viral 3′ UTRs in contributing to differential gene expression during latent versus lytic infection.
Local Blockade of Epithelial PDL-1 in the Airways Enhances T Cell Function and Viral Clearance during Influenza Virus Infection
Authors: McNally Beth , Ye Fang , Willette Meredith , Flaño Emilio
Published: September 2013

In order to maintain the gas exchange function of the lung following influenza virus infection, a delicate orchestration of positive and negative regulatory pathways must be maintained to attain viral eradication while minimizing local inflammation. The programmed death receptor 1 ligand/programmed death receptor 1 (PDL-1/PD-1) pathway plays an important immunoregulatory role, particularly in the context of T cell function. Here, we have shown that influenza virus infection of primary airway epithelial cells strongly enhances PDL-1 expression and does so in an alpha interferon receptor (IFNAR) signaling-dependent manner. PD-1 is expressed primarily on effector T cells in the lung, compared to effector memory and central memory cells, and shortly after influenza virus infection, an increased number of PD-1
+
T cells are recruited to the airways. Using
in vitro
cocultures of airway epithelial cells and T cells and
in vivo
models of influenza virus infection, we have demonstrated that blockade of airway epithelial PDL-1 improves CD8 T cell function, defined by increased production of gamma interferon (IFN-γ) and granzyme B and expression of CD107ab. Furthermore, PDL-1 blockade in the airways served to accelerate influenza virus clearance and enhance infection recovery. Our findings suggest that local manipulation of the PDL-1/PD-1 axis in the airways may represent a therapeutic alternative during acute influenza virus infection.
Impact of corticofugal fibre involvement in subcortical stroke
Authors: Phan Thanh G , van der Voort Sanne , Chen Jian , Beare Richard , Ma Henry , Clissold Benjamin , Ly John , Foster Emma , Thong Eleanor , Srikanth Velandai
Published: September 2013

Objective

To correlate motor deficit with involvement of corticofugal fibres in patients with subcortical stroke. The descending motor corticofugal fibres originate from the primary motor cortex (M1), dorsal and ventral premotor area (PMdv) and supplementary motor area (SMA).

Design

Retrospective study.

Setting

Single tertiary teaching hospital.

Participants

57 patients (57% men) with subcortical infarcts on MRI (2009–2011) were included. The mean age was 64.3±14.4 years.

Interventions

None.

Primary and secondary outcome measures

National Institute of Health Stroke Scale subscores for arm and leg motor deficit at 90 days.

Results

An area under the receiver operating characteristics curve (AUC) for the volume of overlap with infarct (and M1/PMdv/SMA fibres) and motor outcome was calculated. The AUC for the association with arm motor deficit from M1 fibres involvement was 0.80 (95% CI 0.66 to 0.94), PMdv was 0.76 (95% CI 0.61 to 0.91) and SMA was 0.73 (95% CI 0.58 to 0.88). The AUC for leg motor deficit from M1 fibres involvement was 0.69 (95% CI 0.52 to 0.85), PMdv was 0.67 (95% CI 0.50 to 0.85), SMA was 0.66 (95% CI 0.48 to 0.84).

Conclusions

Following subcortical stroke, the correlations between involvement of the corticofugal fibres for upper and lower limbs motor deficit were variable. A poor motor outcome was not universal following subcortical stroke.
Reactive tissue proliferation and damage of elastic lamina caused by hydrogel coated coils in experimental rat aneurysms
Authors: Zhang Chao , Chaudhary Neeraj , Gemmete Joseph J , Thompson B Gregory , Xi Guohua , Pandey Aditya S
Published: September 2013

Background and objective

The HydroCoil Endovascular Aneurysm Occlusion and Packing Study clinical trial, comparing HydroCoil with platinum coils, reported an 8.6% reduction in significant recurrence following cerebral aneurysm coil embolization. We sought to better understand the mechanism of aneurysmal healing following HydroCoil implantation using the rat external carotid artery (ECA) sidewall aneurysm model.

Methods

We ligated the proximal ECA, creating a blind pouch in our rat model. HydroCoil or bare platinum coil segments (5 mm) were inserted into aneurysms. Sham operated rats underwent identical procedures without coil insertion. 14 days after coil embolization, animals were sacrificed and the common carotid artery/internal carotid artery/ECA complex removed. Sac and surrounding vasculature underwent microscopic and histopathologic evaluation. Cellular and fibrotic components within the sac were defined as the organized area. Percentage of organized area and residual length of internal elastic lamina were calculated.

Results

Organized tissue area in ECA sac 2 weeks following coil embolization was significantly greater in the HydroCoil group than the bare coil (60.42±22.58% vs 15.62±19.24%; p=0.01) and sham (60.42±22.58% vs 4.61±3.86%; p=0.002) groups. Elastic lamina was significantly reduced in the HydroCoil group compared with the sham and bare coil groups (21.67±16.50% vs 100% and 96.06±8.78%; both p<0.001). No significant difference was found between the bare coil and sham groups for organized tissue formation or reduction in elastic lamina. Greater numbers of B cells, T cells, and neutrophils were present within HydroCoil induced organized tissue compared with the platinum group; this difference was not statistically significant.

Conclusions

In the rat ECA sidewall aneurysm model, hydrogel coated coils cause more tissue reaction and organization compared with bare platinum coils, possibly attributed to observed elastic lamina damage and vascular smooth muscle cell proliferation.
Physiological and metabolic responses as function of the mechanical load in resistance exercise
Authors: Buitrago Sebastian , Wirtz Nicolas , Flenker Ulrich , Kleinöder Heinz
Published: October 2013

The present study aimed to investigate the relationship between the mechanical load during resistance exercise and the elicited physiological responses. Ten resistance-trained healthy male subjects performed 1 set of resistance exercise each at 55%, 70%, and 85% of 1 repetition maximum for as many repetitions as possible and in 4 training modes: 4-1-4-1 (4 s concentric, 1 s isometric, 4 s eccentric, and 1 s isometric successive actions), 2-1-2-1, 1-1-1-1, and explosive (maximum velocity concentric). Mean concentric power and total concentric work were determined. Oxygen uptake (V̇O2) was measured during exercise and for 30 min post exercise. Total volume of consumed oxygen (O2 consumed) and excess post-exercise oxygen consumption (EPOC) were calculated. Maximum blood lactate concentration (LAmax) was also determined. V̇O2 exhibited a linear dependency on mean concentric power. Mean concentric power did not have a detectable effect on EPOC and LAmax. An augmentation of total concentric work resulted in significant linear increase of O2 consumed and EPOC. Total concentric work caused a significant increase in LAmax. In general, a higher mechanical load induced a larger physiological response. An increase in mean concentric power elicited higher aerobic energy turnover rates. However, a higher extent of total concentric work augments total energy cost covered by oxidative and (or) glycolytic pathways.
Model for prediction of resilient modulus incorporating matric suction for recycled unbound granular materials
Authors: Azam A.M. , Cameron D.A. , Rahman M.M.
Published: September 2013

This paper presents experimental results on the effect of matric suction on the resilient modulus of four recycled unbound granular materials. The recycled materials were prepared at moisture contents ranging between 70% and 90% of optimum moisture content (OMC) and tested in a repeated load triaxial test (RLTT) apparatus under various stress regimes. Soil-water characteristic curves (SWCC) were established for each material by preparing samples at various moisture contents and measuring matric suction with filter papers. To obtain the wet end of the SWCC, further samples were conditioned on a tension plate at suctions controlled by the hanging water column method. Some published models for prediction of resilient modulus were applied to the experimental data, but the correlations were unsatisfactory generally, and so an improved model was sought. Subsequently, a model with four terms and six constants was developed, which followed the general power law. A single set of material constants was found for all recycled materials to provide satisfactory predictions of resilient modulus (R2 = 0.88), over a wide range of stresses and moisture states.
NONRADIAL APPROACH TO ALLOCATING FIXED-COSTS AND COMMON REVENUE USING CENTRALIZED DEA
Authors: LOZANO SEBASTIÁN
Published: October 2013

In this paper, a simple approach to allocating fixed costs and common revenue among different units is presented. It is based on centralized data envelopment analysis (DEA) and uses a weighted, slacks-based, nonradial metric. The approach is units-invariant and takes into account the inefficiencies in the assessed decision making units (DMUs). The approach works when the fixed cost is a complement of another input as well as when no other inputs exist. The proposed approach is compared with existing allocation methods using several datasets from the literature.
A blueprint for building a quantum computer
Authors: Van Meter Rodney , Horsman Dominic
Published: September 2013

Quantum computer architecture holds the key to building commercially viable systems.
The naming of hosts is a difficult matter
Authors: Neville-Neil George V.
Published: September 2013

Also, the perils of premature rebooting.
Software helps linguists reconstruct, decipher ancient languages
Authors: Hyman Paul
Published: September 2013

Linguists who once spent an entire career reconstructing a major language family now can accomplish that in just a few hours.
Online algorithms in high-frequency trading
Authors: Loveless Jacob , Stoikov Sasha , Waeber Rolf
Published: September 2013

The challenges faced by competing HFT algorithms.
Formal verification of phase-locked loops using reachability analysis and continuization
Authors: Althoff Matthias , Rajhans Akshay , Krogh Bruce H. , Yaldiz Soner , Li Xin , Pileggi Larry
Published: September 2013

We present a scalable and formal technique to verify locking time and stability for charge-pump phase-locked loops (PLLs). In contrast to the traditional simulation approach that only validates the PLL at a given operation condition, our proposed technique formally verified the PLL at all possible operation conditions. The dynamics of the PLL is described by a hybrid automaton, which incorporates the differential equations of the analog circuit elements as well as the switching logic of the digital circuit elements. Existing methods for computing reachable sets for hybrid automata cannot be used to verify the PLL model due to the large number of cycles required for locking. We develop a new method for computing effective overapproximations of the sets of states reached on each cycle by using uncertain parameters in a discrete-time model to represent the range of possible switching times, a technique we call
continuization
. Using this new method for reachability analysis, it is possible to verify locking specifications for a charge-pump PLL design for all possible initial states and parameter values in time comparable to the time required for a few simulation runs of the same behavioral model.
What is Public and Private Anyway? A Pragmatic Take on Privacy and Democracy
Authors: Birkbak Andreas
Published: September 2013

Revealing private content on the Web can also spark public engagement. To understand this, we need to challenge our common sense notions of privacy and democracy.
What is Bitcoin?
Authors: Hobson Dominic
Published: September 2013

Strengths and weaknesses of the leader in a new generation of emerging cryptocurrencies.
ColPack
Authors: Gebremedhin Assefaw H. , Nguyen Duc , Patwary Md. Mostofa Ali , Pothen Alex
Published: October 2013

We present a suite of fast and effective algorithms, encapsulated in a software package called ColPack, for a variety of graph coloring and related problems. Many of the coloring problems model partitioning needs arising in compression-based computation of Jacobian and Hessian matrices using Algorithmic Differentiation. Several of the coloring problems also find important applications in many areas outside derivative computation, including frequency assignment in wireless networks, scheduling, facility location, and concurrency discovery and data movement operations in parallel and distributed computing. The presentation in this article includes a high-level description of the various coloring algorithms within a common design framework, a detailed treatment of the theory and efficient implementation of known as well as new vertex ordering techniques upon which the coloring algorithms rely, a discussion of the package's software design, and an illustration of its usage. The article also includes an extensive experimental study of the major algorithms in the package using real-world as well as synthetically generated graphs.
Algorithm 932
Authors: Gander Martin J. , Japhet Caroline
Published: October 2013

We design and analyze an algorithm with linear complexity to perform projections between 2D and 3D nonmatching grids. This algorithm, named the PANG algorithm, is based on an advancing front technique and neighboring information. Its implementation is surprisingly short, and we give the entire Matlab code. For computing the intersections, we use a direct and numerically robust approach. We show numerical experiments both for 2D and 3D grids, which illustrate the optimal complexity and negligible overhead of the algorithm. An outline of this algorithm has already been presented in a short proceedings paper of the 18th International Conference on Domain Decomposition Methods (see Gander and Japhet [2008]).
Algorithm 933
Authors: Foster Leslie V. , Davis Timothy A.
Published: October 2013

The SPQR_RANK package contains routines that calculate the numerical rank of large, sparse, numerically rank-deficient matrices. The routines can also calculate orthonormal bases for numerical null spaces, approximate pseudoinverse solutions to least squares problems involving rank-deficient matrices, and basic solutions to these problems. The algorithms are based on SPQR from SuiteSparseQR (ACM Transactions on Mathematical Software 38, Article 8, 2011). SPQR is a high-performance routine for forming QR factorizations of large, sparse matrices. It returns an estimate for the numerical rank that is usually, but not always, correct. The new routines improve the accuracy of the numerical rank calculated by SPQR and reliably determine the numerical rank in the sense that, based on extensive testing with matrices from applications, the numerical rank is almost always accurately determined when our methods report that the numerical rank should be correct. Reliable determination of numerical rank is critical to the other calculations in the package. The routines work well for matrices with either small or large null space dimensions.
Ascorbate infusion increases skeletal muscle fatigue resistance in patients with chronic obstructive pulmonary disease
Authors: Rossman Matthew J. , Garten Ryan S. , Groot H. Jonathan , Reese Van , Zhao Jia , Amann Markus , Richardson Russell S.
Published: September 2013

Chronic obstructive pulmonary disease (COPD) is associated with systemic oxidative stress and skeletal muscle dysfunction. The purpose of this study was to examine the impact of intravenous ascorbate administration (AO) on biological markers of antioxidant capacity and oxidative stress, and subsequently skeletal muscle function during dynamic, small muscle mass exercise in patients with COPD. Ten patients with spirometric evidence of COPD performed single-leg knee extensor (KE) trials matched for intensity and time (isotime) following intravenous ascorbate (2 g) or saline infusion (PL). Quadriceps fatigue was quantified by changes in force elicited by maximal voluntary contraction (MVC) and magnetic femoral nerve stimulation (Qtw,pot). AO administration significantly increased antioxidant capacity, as measured by the ferric-reducing ability of plasma (PL: 1 ± 0.1 vs. AO: 5 ± 0.2 mM), and significantly reduced malondialdehyde levels (PL: 1.16 ± 0.1 vs. AO: 0.97 ± 0.1 mmol). Additionally, resting blood pressure was significantly reduced (PL: 104 ± 4 vs. AO: 93 ± 6 mmHg) and resting femoral vascular conductance was significantly elevated after AO (PL: 2.4 ± 0.2 vs. AO: 3.6 ± 0.4 ml·min−1·mmHg−1). During isotime exercise, the AO significantly attenuated both the ventilatory and metabolic responses, and patients accumulated significantly less peripheral quadriceps fatigue, as illustrated by less of a fall in MVC (PL: −11 ± 2% vs. AO: −5 ± 1%) and Qtw,pot (PL: −37 ± 1% vs. AO: −30 ± 2%). These data demonstrate a beneficial role of AO administration on skeletal muscle fatigue in patients with COPD and further implicate systemic oxidative stress as a causative factor in the skeletal muscle dysfunction observed in this population.
Altered cortical spectrotemporal processing with age-related hearing loss
Authors: Trujillo Michael , Razak Khaleel A.
Published: September 2013

Presbycusis (age-related hearing loss) is a prevalent disability associated with aging that impairs spectrotemporal processing, but the mechanisms of such changes remain unclear. The goal of this study was to quantify cortical responses to frequency-modulated (FM) sweeps in a mouse model of presbycusis. Previous studies showed that cortical neurons in young mice are selective for the rate of frequency change in FM sweeps. Here single-unit data on cortical selectivity and response variability to FM sweeps of either direction and different rates (0.08–20 kHz/ms) were compared across young (1–3 mo), middle-aged (6–8 mo), and old (14–20 mo) groups. Three main findings are reported. First, there is a reduction in FM rate selectivity in the old group. Second, there is a slowing of the sweep rates at which neurons likely provide best detection and discrimination of sweep rates. Third, there is an increase in trial-to-trial variability in the magnitude and timing of spikes in response to sweeps. These changes were only observed in neurons that were selective for the fast or intermediate range of sweep rates and not in neurons that preferred slow sweeps or were nonselective. Increased variability of response magnitude, but not changes in temporal fidelity or selectivity, was seen even in the middle-aged group. The results show that spectrotemporal processing becomes slow and noisy with presbycusis in specific types of neurons, suggesting receptive field mechanisms that are altered. These data suggest neural correlates of presbycusis-related reduction in the ability of humans to process rapid spectrotemporal changes.
Dynamic Characteristics of Rotating Stall in Mixed Flow Pump
Authors: Li Xiaojun , Yuan Shouqi , Pan Zhongyong , Li Yi , Liu Wei
Published: October 2013

Rotating stall, a phenomenon that causes flow instabilities and pressure hysteresis by propagating at some fraction of the impeller rotational speed, can occur in centrifugal impellers, mixed impellers, radial diffusers, or axial diffusers. Despite considerable efforts devoted to the study of rotating stall in pumps, the mechanics of this phenomenon are not sufficiently understood. The propagation mechanism and onset of rotating stall are not only affected by inlet flow but also by outlet flow as well as the pressure gradient in the flow passage. As such, the complexity of these concepts is not covered by the classical explanation. To bridge this research gap, the current study investigated prerotation generated at the upstream of the impeller, leakage flow at the tip clearance between the casing and the impeller, and strong reserve flow at the inlet of the diffuser. Understanding these areas will clarify the origin of the positive slope of the head-flow performance curve for a mixed flow pump. Nonuniform pressure distribution and adverse pressure gradient were also introduced to evaluate the onset and development of rotating stall within the diffuser.
Formation of a Tunnel under the Major Hepatic Vein Mouths during Removal of IVC Tumor Thrombus
Authors: Shchukin Dmytro
Published: September 2013

This study describes a clinical observation of successful implementation of a new surgical maneuver: formation of a cross tunnel under the mouths of the major hepatic veins during removal of a tumor thrombus of the inferior vena cava. This surgical technique helps avoid the usage of   “piggyback” mobilization of the liver and the complications associated with it. However, for objective evaluation of this approach, a further clinical study is required.
The Bifurcations of Traveling Wave Solutions of the Kundu Equation
Authors: Yi Yating , Liu Zhengrong
Published: October 2013

We use the bifurcation method of dynamical systems to study the bifurcations of traveling wave solutions for the Kundu equation. Various explicit traveling wave solutions and their bifurcations are obtained. Via some special phase orbits, we obtain some new explicit traveling wave solutions. Our work extends some previous results.
Synchronization of Complex Dynamical Networks with Nonidentical Nodes and Derivative Coupling via Distributed Adaptive Control
Authors: Shi Miao , Li Junmin , He Chao
Published: September 2013

Adaptive synchronization control is proposed for a new complex dynamical network model with nonidentical nodes and nonderivative and derivative couplings. The distributed adaptive learning laws of periodically time-varying and constant parameters and distributed adaptive control are designed. The new method which can obtain the synchronization error of closed-loop complex network system is asymptotic convergence in the sense of square error norm. What is more, the coupling matrix is not assumed to be symmetric or irreducible. Finally, a simulation example shows the feasibility and effectiveness of the approach.
Global Asymptotic Stability for Nonlinear Functional Integral Equation of Mixed Type
Authors: Xia Zhinan
Published: October 2013

The existence results of global asymptotic stability of the solution are proved for functional integral equation of mixed type. The measure of noncompactness and the fixed-point theorem of Darbo are the main tools in carrying out our proof. Furthermore, some examples are given to show the efficiency and usefulness of the main findings.
Prenatal Ultrasound Screening for Fetal Anomalies and Outcomes in High-Risk Pregnancies due to Maternal HIV Infection: A Retrospective Study
Authors: Reitter A. , Stücker A. U. , Buxmann H. , Herrmann E. , Haberl A. E. , Schlößer R. , Louwen F.
Published: September 2013

Objective. To assess the prevalence of prenatal screening and of adverse outcome in high-risk pregnancies due to maternal HIV infection.Study Design. The prevalence of prenatal screening in 330 pregnancies of HIV-positive women attending the department for prenatal screening and/or during labour between January 1, 2002 and December 31, 2012, was recorded. Screening results were compared with the postnatal outcome and maternal morbidity, and mother-to-child transmission (MTCT) was evaluated.Results. One hundred of 330 women (30.5%) had an early anomaly scan, 252 (74.5%) had a detailed scan at 20–22 weeks, 18 (5.5%) had a detailed scan prior to birth, and three (0.9%) had an amniocentesis. In seven cases (2.12%), a fetal anomaly was detected prenatally and confirmed postnatally, while in eight (2.42%) an anomaly was only detected postnatally, even though a prenatal scan was performed. There were no anomalies in the unscreened group. MTCT occurred in three cases (0.9%) and seven fetal and neonatal deaths (2.1%) were reported.Conclusion. The overall prevalence of prenatal ultrasound screening in our cohort is 74.5%, but often the opportunity for prenatal ultrasonography in the first trimester is missed. In general, the aim should be to offer prenatal ultrasonography in the first trimester in all pregnancies. This allows early reassurance or if fetal disease is suspected, further steps can be taken.