bluuebunny/crossref_metadata_2025 huggingface dataset:
Storage of apheresis platelet concentrates after manual replacement of >95% of plasma with PAS 5
Authors: Morrison A. , McMillan L. , Radwanski K. , Blatchford O. , Min K. , Petrik J.
Published: May 2014

Background and Objectives

Recently, a glucose‐ and bicarbonate‐containing additive solution termed PAS 5 demonstrated acceptable 7‐day platelet storage after >95% plasma replacement with PAS on the day of collection (Day 0). In this study, we examined platelet storage in >95% PAS 5 after manual washing of Day 1 apheresis platelets in plasma collected using either the Amicus or Trima plateletpheresis devices.

Material and Methods

Triple platelet donations in plasma were obtained from Amicus (n = 10) and Trima (n = 10) plateletpheresis devices and stored overnight before being centrifuged and manually processed into three units with the following storage media: 100% plasma, >95% PAS 5 or 65% PAS 5/35% plasma. Platelet units were sampled on Days 1, 5 and 7 of storage using a range of tests recommended by the UK guidelines.

Results

The majority of in vitro assay results for platelets in PAS 5 were similar to results in paired 100% plasma platelets (controls). The pH of PAS 5 stored platelet units was above the UK recommended guidelines of 7·4 by Day 5. PAS 5 platelets were no more activated than controls as evidenced by comparable soluble P‐selectin levels and CD62p and CD42b expression. PAS 5 platelets also exhibited adhesion and aggregation profiles higher than (Day 1) or comparable to (Days 5 and 7) controls as measured by Impact R.

Conclusion

The 7‐day in vitro storage parameters investigated were comparable between >95% PAS 5 and 100% plasma platelets derived from both Amicus and Trima plateletpheresis devices, with the exception that lactose dehydrogenase release rate and pH were significantly higher in PAS 5 units.
Performance Analysis of Oil Lubricated Foil Bearing With Flexible Supported Back Spring Structure—Part I: Model Development and Numerical Investigation
Authors: Zhang Guanghui , Liang Xie , Wang Yu , Liu Zhansheng
Published: May 2014

A new type of multileaf oil lubricated foil bearing with flexible supported back spring structure was proposed to satisfy the requirement of high rotating velocity for turbo pump, where the rotor was submerged in the hydraulic oil. The numerical analysis was carried out in this paper. Based on the structure of oil foil bearing, the film thickness model was established without foil deformation. By employing Castigliano's theorem, the total flexibility matrix including the elastic back spring and cantilevered curved beam was calculated, and then compared with commercial finite element software to verify the accuracy of the proposed model. The obtained flexibility matrix was brought into the static and dynamic oil lubricated Reynolds equation. The Reynolds boundary condition was considered to simulate the oil film rupture effect. The deformation equation for the structure and the Reynolds equation were solved coupled by the successive over relaxation method. The static and dynamic characteristics of the oil lubricated multileaf foil bearing with supported back spring were acquired. The effect of the foil thickness on the load capacity was discussed. The variation of the dynamic coefficients with bearing load was acquired. By employing Routh–Hurwitz method, the stability of the bearing was analyzed. The results indicated that the load capacity of the foil bearing with back supported spring was bigger than that of the foil bearing without back supported spring. The stability characteristics of the foil bearing with back supported structure was better than traditional rigid self-acting bearing, particular for the high rotating speed case.
A Computational Method for Predicting Inferior Vena Cava Filter Performance on a Patient-Specific Basis
Authors: Aycock Kenneth I. , Campbell Robert L. , Manning Keefe B. , Sastry Shankar P. , Shontz Suzanne M. , Lynch Frank C. , Craven Brent A.
Published: May 2014

A computational methodology for simulating virtual inferior vena cava (IVC) filter placement and IVC hemodynamics was developed and demonstrated in two patient-specific IVC geometries: a left-sided IVC and an IVC with a retroaortic left renal vein. An inverse analysis was performed to obtain the approximate in vivo stress state for each patient vein using nonlinear finite element analysis (FEA). Contact modeling was then used to simulate IVC filter placement. Contact area, contact normal force, and maximum vein displacements were higher in the retroaortic IVC than in the left-sided IVC (144 mm2, 0.47 N, and 1.49 mm versus 68 mm2, 0.22 N, and 1.01 mm, respectively). Hemodynamics were simulated using computational fluid dynamics (CFD), with four cases for each patient-specific vein: (1) IVC only, (2) IVC with a placed filter, (3) IVC with a placed filter and model embolus, all at resting flow conditions, and (4) IVC with a placed filter and model embolus at exercise flow conditions. Significant hemodynamic differences were observed between the two patient IVCs, with the development of a right-sided jet, larger flow recirculation regions, and lower maximum flow velocities in the left-sided IVC. These results support further investigation of IVC filter placement and hemodynamics on a patient-specific basis.
Scala-Tympani Phantom With Cochleostomy and Round-Window Openings for Cochlear-Implant Insertion Experiments
Authors: Leon Lisandro , Cavilla Matt S. , Doran Michael B. , Warren Frank M. , Abbott Jake J.
Published: May 2014

Experiments with scala-tympani (ST) phantoms are used to evaluate new electrode arrays and cochlear-implant insertion techniques. To date, phantoms have not accounted for clinical orientations and geometric differences between round-window (RW) insertions and anteroinferior cochleostomy insertions. For improved assessments of insertion experiments, we present a scala-tympani phantom that offers three distinct benefits over previous phantoms: it mimics the standard otologic position, it accommodates for both round-window and anteroinferior cochleostomy insertions, and it incorporates a visual coordinate system based on industry consensus making standardized angular measurements possible.
A Highly Adjustable Base Isolator Utilizing Magnetorheological Elastomer: Experimental Testing and Modeling
Authors: Li Yancheng , Li Jianchun
Published: May 2014

This paper presents a recent research advance on the development of a novel adaptive seismic isolation system to be used in seismic protection of civil structures. A highly adjustable laminated magnetorheological elastomer (MRE) base isolator was developed and experimental results show that the prototypical MRE base isolator provides increase in lateral stiffness up to 1630%. To facilitate the structural control development using such adaptive MRE base isolator, an analytical model was developed to simulate its behaviors. Comparison between the analytical model and experimental data proves the effectiveness of such model in reproducing the behavior of MRE base isolator.
Vigorous Physical Activity may be Important for the Insulin Sensitivity in Immigrants From the Middle East and Native Swedes
Authors: Arvidsson Daniel , Lindblad Ulf , Sundquist Jan , Sundquist Kristina , Groop Leif , Bennet Louise
Published: May 2014

Purpose:

To compare physical activity measures and their associations with insulin sensitivity, β-cell function and body mass index (BMI) between Iraqi immigrants and native Swedes.

Methods:

A cross-sectional study of 493 Iraqis (58% men) and 469 Swedes (54% men) aged 30 to 75 years living in the city of Malmö, Sweden. Accelerometry was used for physical activity measures (sedentary time, breaks in sedentary time, moderate and vigorous physical activity, total counts). Insulin sensitivity index and oral disposal index were determined from an oral glucose tolerance test and BMI by body weight and height.

Results:

Iraqi men were less physically active than Swedish men, while the physical activity was more similar in the women. BMI was a strong predictor of insulin sensitivity and β-cell function and frequently associated with the physical activity measures. BMI modified the associations of insulin sensitivity and β-cell function with the physical activity measures to such extent that only VPA and total counts show direct associations with insulin sensitivity in addition to the indirect associations via BMI. Iraqi women demonstrated weaker associations compared with Swedish women.

Conclusions:

Physical activity and performed at vigorous intensity may be important mainly for the insulin sensitivity in Iraqi immigrants and native Swedes.
Exercise and Food Compensation: Exploring Diet-Related Beliefs and Behaviors of Regular Exercisers
Authors: Dohle Simone , Wansink Brian , Zehnder Lorena
Published: May 2014

Background:

The goal of this qualitative study is to identify common beliefs and behaviors related to exercise and diet.

Methods:

Data were collected in focus group discussions with regular exercisers who were physically active between 1 and 5 h per week. Exercise objectives, beliefs and behaviors regarding food intake before, during, and after exercise, consumption of sport supplements, and dietary patterns on sedentary days were explored. All focus groups were audio-taped and transcribed verbatim. Transcripts were analyzed using a grounded theory approach.

Results:

Participants reported that they reward themselves for being active by consuming food. Other exercisers had specific beliefs about dietary needs and how to compensate for exercise-induced losses along with exercise-related food likes and dislikes. The participants’ food intake also depended on their personal exercise objectives, such as the goal of performing well in competitions. External and physiological factors also played a role in determining participants’ dietary patterns.

Conclusions:

Results of this study show that exercising and dietary patterns are closely intertwined. In addition, we articulate new hypotheses and outline a research agenda that can help improve how regular exercisers eat.
Three-Year Follow-Up of an Early Childhood Intervention: What About Physical Activity and Weight Status?
Authors: Barnett Lisa M. , Zask Avigdor , Rose Lauren , Hughes Denise , Adams Jillian
Published: May 2014

Background:

Fundamental movement skills are a correlate of physical activity and weight status. Children who participated in a preschool intervention had greater movement skill proficiency and improved anthropometric measures (waist circumference and BMI z scores) post intervention. Three years later, intervention girls had retained their object control skill advantage. The study purpose was to assess whether at 3-year follow up a) intervention children were more physically active than controls and b) the intervention effect on anthropometrics was still present.

Methods:

Children were assessed at ages 4, 5, and 8 years for anthropometric measures and locomotor and object control proficiency (Test of Gross Motor Development-2). At age 8, children were also assessed for moderate to vigorous physical activity (MVPA) (using accelerometry). Several general linear models were run, the first with MVPA as the outcome, intervention/control, anthropometrics, object control and locomotor scores as predictors, and age and sex as covariates. The second and third models were similar, except baseline to follow-up anthropometric differences were the outcome.

Results:

Overall follow-up rate was 29% (163/560), with 111 children having complete data. There were no intervention control differences in either MVPA or anthropometrics.

Conclusion:

Increased skill competence did not translate to increased physical activity.
Magnetic Resonance: It’s a Gas!
Authors: Drum Chester L.
Published: May 2014

A genetically encoded magnetic resonance imaging (MRI) reporter uses bacterial proteins to encapsulate nanosized bubbles of xenon gas.
Differences in Lactococcal Cell Wall Polysaccharide Structure Are Major Determining Factors in Bacteriophage Sensitivity
Authors: Ainsworth Stuart , Sadovskaya Irina , Vinogradov Evguenii , Courtin Pascal , Guerardel Yann , Mahony Jennifer , Grard Thierry , Cambillau Christian , Chapot-Chartier Marie-Pierre , van Sinderen Douwe
Published: May 2014

Analysis of the genetic locus encompassing a cell wall polysaccharide (CWPS) biosynthesis operon of eight strains of
Lactococcus lactis
, identified as belonging to the same CWPS type C genotype, revealed the presence of a variable region among the strains examined. The results allowed the identification of five subgroups of the C type named subtypes C
1
to C
5
. This variable region contains genes encoding glycosyltransferases that display low or no sequence homology between the subgroups. In this study, we purified an acidic polysaccharide from the cell wall of
L. lactis
3107 (subtype C
2
) and confirmed that it is structurally different from the previously established CWPS of subtype C
1
L. lactis
MG1363. The CWPS of
L. lactis
3107 is composed of pentasaccharide repeating units linked by phosphodiester bonds with the structure 6-α-Glc-3-β-Gal
f
-3-β-GlcNAc-2-β-Gal
f
-6-α-GlcNAc-1-
P
. Combinations of genes from the variable region of subtype C
2
were introduced into a mutant of subtype C
1
L. lactis
NZ9000 deficient in CWPS biosynthesis. The resulting recombinant mutant synthesized a polysaccharide with a composition characteristic of that of subtype C
2
L. lactis
3107 and not wild-type C
1
L. lactis
NZ9000. By challenging the recombinant mutant with various lactococcal phages, we demonstrated that CWPS is the host cell surface receptor of tested bacteriophages of both the P335 and 936 groups and that differences between the CWPS structures play a crucial role in determining phage host range
.

IMPORTANCE
Despite the efforts of nearly 80 years of lactococcal phage research, the precise nature of the cell surface receptors of the P335 and 936 phage group receptors has remained elusive. This work demonstrates the molecular nature of a P335 group receptor while bolstering the evidence of its role in host recognition by phages of the 936 group and at least partially explains why such phages have a very narrow host range. The information generated will be instrumental in understanding the molecular mechanisms of how phages recognize specific saccharidic receptors located on the surface of their bacterial host.
Microbiome Data Distinguish Patients with Clostridium difficile Infection and Non-C. difficile-Associated Diarrhea from Healthy Controls
Authors: Schubert Alyxandria M. , Rogers Mary A. M. , Ring Cathrin , Mogle Jill , Petrosino Joseph P. , Young Vincent B. , Aronoff David M. , Schloss Patrick D.
Published: May 2014

Antibiotic usage is the most commonly cited risk factor for hospital-acquired
Clostridium difficile
infections (CDI). The increased risk is due to disruption of the indigenous microbiome and a subsequent decrease in colonization resistance by the perturbed bacterial community; however, the specific changes in the microbiome that lead to increased risk are poorly understood. We developed statistical models that incorporated microbiome data with clinical and demographic data to better understand why individuals develop CDI. The 16S rRNA genes were sequenced from the feces of 338 individuals, including cases, diarrheal controls, and nondiarrheal controls. We modeled CDI and diarrheal status using multiple clinical variables, including age, antibiotic use, antacid use, and other known risk factors using logit regression. This base model was compared to models that incorporated microbiome data, using diversity metrics, community types, or specific bacterial populations, to identify characteristics of the microbiome associated with CDI susceptibility or resistance. The addition of microbiome data significantly improved our ability to distinguish CDI status when comparing cases or diarrheal controls to nondiarrheal controls. However, only when we assigned samples to community types was it possible to differentiate cases from diarrheal controls. Several bacterial species within the
Ruminococcaceae
,
Lachnospiraceae
,
Bacteroides
, and
Porphyromonadaceae
were largely absent in cases and highly associated with nondiarrheal controls. The improved discriminatory ability of our microbiome-based models confirms the theory that factors affecting the microbiome influence CDI.

IMPORTANCE
The gut microbiome, composed of the trillions of bacteria residing in the gastrointestinal tract, is responsible for a number of critical functions within the host. These include digestion, immune system stimulation, and colonization resistance. The microbiome’s role in colonization resistance, which is the ability to prevent and limit pathogen colonization and growth, is key for protection against
Clostridium difficile
infections. However, the bacteria that are important for colonization resistance have not yet been elucidated. Using statistical modeling techniques and different representations of the microbiome, we demonstrated that several community types and the loss of several bacterial populations, including
Bacteroides
,
Lachnospiraceae
, and
Ruminococcaceae
, are associated with CDI. Our results emphasize the importance of considering the microbiome in mediating colonization resistance and may also direct the design of future multispecies probiotic therapies.
Mycobacterial Esx-3 Requires Multiple Components for Iron Acquisition
Authors: Siegrist M. Sloan , Steigedal Magnus , Ahmad Rushdy , Mehra Alka , Dragset Marte S. , Schuster Brian M. , Philips Jennifer A. , Carr Steven A. , Rubin Eric J.
Published: May 2014

The type VII secretion systems are conserved across mycobacterial species and in many Gram-positive bacteria. While the well-characterized Esx-1 pathway is required for the virulence of pathogenic mycobacteria and conjugation in the model organism
Mycobacterium smegmatis
, Esx-3 contributes to mycobactin-mediated iron acquisition in these bacteria. Here we show that several Esx-3 components are individually required for function under low-iron conditions but that at least one, the membrane-bound protease MycP
3
of
M. smegmatis
, is partially expendable. All of the
esx-3
mutants tested, including the Δ
mycP

3ms

mutant, failed to export the native Esx-3 substrates EsxH

ms

and EsxG

ms

to quantifiable levels, as determined by targeted mass spectrometry. Although we were able to restore low-iron growth to the
esx-3
mutants by genetic complementation, we found a wide range of complementation levels for protein export. Indeed, minute quantities of extracellular EsxH

ms

and EsxG

ms

were sufficient for iron acquisition under our experimental conditions. The apparent separation of Esx-3 function in iron acquisition from robust EsxG

ms

and EsxH

ms

secretion in the
ΔmycP

3ms

mutant and in some of the complemented
esx-3
mutants compels reexamination of the structure-function relationships for type VII secretion systems.

IMPORTANCE
Mycobacteria have several paralogous type VII secretion systems, Esx-1 through Esx-5. Whereas Esx-1 is required for pathogenic mycobacteria to grow within an infected host, Esx-3 is essential for growth
in vitro
. We and others have shown that Esx-3 is required for siderophore-mediated iron acquisition. In this work, we identify individual Esx-3 components that contribute to this process. As in the Esx-1 system, most mutations that abolish Esx-3 protein export also disrupt its function. Unexpectedly, however, ultrasensitive quantitation of Esx-3 secretion by multiple-reaction-monitoring mass spectrometry (MRM-MS) revealed that very low levels of export were sufficient for iron acquisition under similar conditions. Although protein export clearly contributes to type VII function, the relationship is not absolute.
Detection of Evolutionarily Distinct Avian Influenza A Viruses in Antarctica
Authors: Hurt Aeron C. , Vijaykrishna Dhanasekaran , Butler Jeffrey , Baas Chantal , Maurer-Stroh Sebastian , Silva-de-la-Fuente M. Carolina , Medina-Vogel Gonzalo , Olsen Bjorn , Kelso Anne , Barr Ian G. , González-Acuña Daniel
Published: May 2014

Distinct lineages of avian influenza viruses (AIVs) are harbored by spatially segregated birds, yet significant surveillance gaps exist around the globe. Virtually nothing is known from the Antarctic. Using virus culture, molecular analysis, full genome sequencing, and serology of samples from Adélie penguins in Antarctica, we confirmed infection by H11N2 subtype AIVs. Their genetic segments were distinct from all known contemporary influenza viruses, including South American AIVs, suggesting spatial separation from other lineages. Only in the matrix and polymerase acidic gene phylogenies did the Antarctic sequences form a sister relationship to South American AIVs, whereas distant phylogenetic relationships were evident in all other gene segments. Interestingly, their neuraminidase genes formed a distant relationship to all avian and human influenza lineages, and the polymerase basic 1 and polymerase acidic formed a sister relationship to the equine H3N8 influenza virus lineage that emerged during 1963 and whose avian origins were previously unknown. We also estimated that each gene segment had diverged for 49 to 80 years from its most closely related sequences, highlighting a significant gap in our AIV knowledge in the region. We also show that the receptor binding properties of the H11N2 viruses are predominantly avian and that they were unable to replicate efficiently in experimentally inoculated ferrets, suggesting their continuous evolution in avian hosts. These findings add substantially to our understanding of both the ecology and the intra- and intercontinental movement of Antarctic AIVs and highlight the potential risk of an incursion of highly pathogenic AIVs into this fragile environment.

IMPORTANCE
Avian influenza viruses (AIVs) are typically maintained and spread by migratory birds, resulting in the existence of distinctly different viruses around the world. However, AIVs have not previously been detected in Antarctica. In this study, we characterized H11N2 viruses sampled from Adélie penguins from two geographically different sites in Antarctica and show that the segmented AIV genome diverged between 49 and 80 years ago from other AIVs, with several genes showing similarity and shared ancestry with H3N8 equine influenza viruses. This study provides the first insight into the ecology of AIVs in Antarctica and highlights the potential risk of an introduction of highly pathogenic AIVs into the continent.
The effects of an urban renewal project on health and health inequalities: a quasi-experimental study in Barcelona
Authors: Mehdipanah Roshanak , Rodríguez-Sanz Maica , Malmusi Davide , Muntaner Carles , Díez Elia , Bartoll Xavier , Borrell Carme
Published: May 2014

Background

In the last decade, the Neighbourhoods Law in Catalonia (Spain) funded municipalities that presented urban renewal projects within disadvantaged neighbourhoods focusing on physical, social and economic improvements. The objective of the study was to evaluate the effects of this law on the health and health inequalities of residents in the intervened neighbourhoods in the city of Barcelona.

Methods

A quasi-experimental predesign and postdesign was used to compare adult residents in five intervened neighbourhoods with eight non-intervened comparison neighbourhoods with similar socioeconomic characteristics. The Barcelona Health Survey was used for studying self-rated and mental health in pre (2001, 2006) and post (2011) years. Poisson regression models stratified by sex were used to compute prevalence ratios comparing 2011 with 2006, and later stratified by social class, to study health inequalities.

Results

The intervened neighbourhoods had a significant decrease in poor self-rated health in both sexes while no significant changes occurred in the comparison group. When stratified by social class, a significant improvement was observed in poor self-rated health in the manual group of the intervened neighbourhoods in both sexes, resulting in a decrease in self-rated health inequalities. Similar results were observed in poor mental health of women, while in men, poor mental health worsens in both neighbourhood groups but mostly in the comparison group.

Conclusions

The Neighbourhoods Law had a positive effect on self-rated health and seems to prevent poor mental health increases in both sexes and especially among manual social classes.
Modelling resilient modulus seasonal variation of silty sand subgrade soils with matric suction control
Authors: Salour Farhad , Erlingsson Sigurdur , Zapata Claudia E.
Published: May 2014

The resilient modulus of unbound materials is an important parameter in the mechanistic design of pavements. Although unbound layers are frequently in a partially saturated state, a total stress approach is conventionally used in modeling the material behaviour, and therefore pore pressure effects are not considered. In fine-grained unbound materials, the saturation state can affect their mechanical behaviour due to pore pressure effects. In this study a modified test procedure and a predictive resilient modulus model that takes into account the subgrade soil matric suction as a stress state variable is presented. Two different silty sand subgrade materials were tested in unsaturated conditions using a series of repeated load triaxial tests under controlled pore suction conditions to study its influence on the resilient modulus. The test data were further used to obtain the resilient modulus model regression parameters that account for moisture content variations through the matric suction parameter. Generally, the prediction model could effectively capture the resilient modulus behaviour of the subgrades with respect to changes in the normal stress state and the matric suction. Given the completeness of this method, this prediction model is recommended as an improved approach in capturing the moisture content effects on the material stiffness properties.
Constraining the anisotropy of the universe from supernovae and gamma-ray bursts
Authors: Chang Zhe , Li Xin , Lin Hai-Nan , Wang Sai
Published: May 2014

Recently, an anisotropic cosmological model was proposed. An arbitrary one-form, which picks out a privileged axis in the universe, was added to the Friedmann–Robertson–Walker (FRW) line element. The distance-redshift relation was modified such that it is direction-dependent. In this paper, we use the Union2 dataset and 59 high-redshift gamma-ray bursts (GRBs) to give constraints on the anisotropy of the universe. The results show that the magnitude of anisotropy is about D = -0.044±0.018, and the privileged axis points toward the direction (l0, b0) = (306.1°±18.7°, -18.2°±11.2°) in the galactic coordinate system. The anisotropy is small and the isotropic cosmological model is an excellent approximation.
Generalized relativistic wave equations with intrinsic maximum momentum
Authors: Ching Chee Leong , Ng Wei Khim
Published: May 2014

We examine the nonperturbative effect of maximum momentum on the relativistic wave equations. In momentum representation, we obtain the exact eigen-energies and wave functions of one-dimensional Klein–Gordon and Dirac equation with linear confining potentials, and the Dirac oscillator. Bound state solutions are only possible when the strength of scalar potential is stronger than vector potential. The energy spectrum of the systems studied is bounded from above, whereby classical characteristics are observed in the uncertainties of position and momentum operators. Also, there is a truncation in the maximum number of bound states that is allowed. Some of these quantum-gravitational features may have future applications.
Scalar-field theory of dark matter
Authors: Huang Kerson , Xiong Chi , Zhao Xiaofei
Published: May 2014

We develop a theory of dark matter based on a previously proposed picture, in which a complex vacuum scalar field makes the universe a superfluid, with the energy density of the superfluid giving rise to dark energy, and variations from vacuum density giving rise to dark matter. We formulate a nonlinear Klein–Gordon equation to describe the superfluid, treating galaxies as external sources. We study the response of the superfluid to the galaxies, in particular, the emergence of the dark-matter galactic halo, contortions during galaxy collisions and the creation of vortices due to galactic rotation.
Entropy of near-extremal rotating charged black holes in four-dimensional supergravity from AdS2/CFT1 correspondence
Authors: Peng Jun-Jin , Hu Qing-Ping
Published: May 2014

We study microscopic entropy of the near-extremal rotating black hole in four-dimensional (4D) 𝒩 = 2 supergravity with four charges set pairwise equal from AdS2/CFT1 correspondence. This correspondence is realized in terms of asymptotic symmetries of the AdS2 geometry and a two-dimensional near-horizon effective quantum theory of residual fields from a dimensional reduction proposed by Robinson and Wilczek. We compute the relevant central charge and derive the microscopic entropy of this near-extremal black hole by Cardy formula. Our results can be extended to more general near-extremal rotating black holes in 4D supergravity. They further support the notion that black hole entropy is generally controlled by near-horizon conformal symmetry.
Magnetoelectric effect in radially polarized disk–ring composites
Authors: Zhang Ru , Wu Gaojian , Zhang Ning
Published: May 2014

A theoretical model is presented for the frequency response of magnetoelectric (ME) effect in the magnetostrictive-piezoelectric (MS-PE) disk–ring composite structures with the PE ring polarized radially. Based on the governing equations of materials and elastodynamic equations of continuum media, the expressions of the ME voltage coefficients for the axial and vertical mode are derived in terms of materials parameters and geometry dimensions. Estimated ME voltage coefficient versus frequency profiles predict a giant ME effect at the electromechanical resonance (EMR) with strong interfacial mechanical coupling. It is shown that increased effective length due to radial polarization instead of thickness polarization of PE-ring is responsible for the improved ME effect in the radially polarized disk–ring structure. The dependences of low-frequency ME effect, resonance frequency and resonance ME effect on geometry dimensions are predicted by our model. Some of the theoretical results are compared with the experimental results, showing good coincidence. It is suggested that proper resonance frequency and better ME effect in the disk–ring structure can be obtained by selecting appropriate materials, optimizing polarization direction and varying its geometry dimensions, which is of interest for the potential application of ME composites in novel multifunctional devices, such as sensors, transducers and memories.
Generalized three-party sharing of operations on remote single qutrit
Authors: Xing Pengfei , Liu Yimin , Xie Chuanmei , Liu Xiansong , Zhang Zhanjun
Published: May 2014

Two three-party schemes are put forward for sharing quantum operations on a remote qutrit with local operation and classical communication as well as shared entanglements. The first scheme uses a two-qutrit and three-qutrit non-maximally entangled states as quantum channels, while the second replaces the three-qutrit non-maximally entangled state with a two-qutrit. Both schemes are treated and compared from the four aspects of quantum and classical resource consumption, necessary-operation complexity, success probability and efficiency. It is found that the latter is overall more optimal than the former as far as a restricted set of operations is concerned. In addition, comparisons of both schemes with other four relevant ones are also made to show their two features, including degree generalization and channel-state generalization. Furthermore, some concrete discussions on both schemes are made to expose their important features of security, symmetry and experimental feasibility. Particularly, it is revealed that the success probabilities and intrinsic efficiencies in both schemes are completely determined by the shared entanglement.
Space-Time Matching Algorithms for Interest Management in Distributed Virtual Environments
Authors: Liu Elvis S. , Theodoropoulos Georgios K.
Published: May 2014

Interest management in Distributed Virtual Environments (DVEs) is a data-filtering technique designed to reduce bandwidth consumption and therefore enhances the scalability of the system. This technique usually involves a process called
interest matching
, which determines what data should be sent to the participants as well as what data should be filtered. Although most of the existing interest matching approaches have been shown to meet their runtime performance requirements, they have a fundamental disadvantage—they perform interest matching at discrete time intervals. As a result, they would fail to report events between discrete timesteps. If participants of the DVE ignore these missing events, they would most likely perform incorrect simulations. This article presents a new approach called
space-time interest matching
, which aims to capture the missing events between discrete timesteps. Although this approach requires additional matching effort, a number of novel algorithms are developed to significantly improve its runtime efficiency.
Partial-Observation Stochastic Games
Authors: Chatterjee Krishnendu , Doyen Laurent
Published: May 2014

In two-player finite-state stochastic games of partial observation on graphs, in every state of the graph, the players simultaneously choose an action, and their joint actions determine a probability distribution over the successor states. The game is played for infinitely many rounds and thus the players construct an infinite path in the graph. We consider reachability objectives where the first player tries to ensure a target state to be visited almost-surely (i.e., with probability 1) or positively (i.e., with positive probability), no matter the strategy of the second player.

We classify such games according to the information and to the power of randomization available to the players. On the basis of information, the game can be
one-sided
with either (
a
) player 1, or (
b
) player 2 having partial observation (and the other player has perfect observation), or
two-sided
with (
c
) both players having partial observation. On the basis of randomization, (
a
) the players may not be allowed to use randomization (pure strategies), or (
b
) they may choose a probability distribution over actions but the actual random choice is external and not visible to the player (actions invisible), or (
c
) they may use full randomization.

Our main results for pure strategies are as follows: (1) For one-sided games with player 2 having perfect observation we show that (in contrast to full randomized strategies)
belief-based
(subset-construction based) strategies are not sufficient, and we present an exponential upper bound on memory both for almost-sure and positive winning strategies; we show that the problem of deciding the existence of almost-sure and positive winning strategies for player 1 is EXPTIME-complete and present symbolic algorithms that avoid the explicit exponential construction. (2) For one-sided games with player 1 having perfect observation we show that nonelementary memory is both necessary and sufficient for both almost-sure and positive winning strategies. (3) We show that for the general (two-sided) case finite-memory strategies are sufficient for both positive and almost-sure winning, and at least nonelementary memory is required. We establish the equivalence of the almost-sure winning problems for pure strategies and for randomized strategies with actions invisible. Our equivalence result exhibit serious flaws in previous results of the literature: we show a nonelementary memory lower bound for almost-sure winning whereas an exponential upper bound was previously claimed.
Parity Games and Propositional Proofs
Authors: Beckmann Arnold , Pudlák Pavel , Thapen Neil
Published: May 2014

A propositional proof system is
weakly automatizable
if there is a polynomial time algorithm that separates satisfiable formulas from formulas that have a short refutation in the system, with respect to a given length bound. We show that if the resolution proof system is weakly automatizable, then parity games can be decided in polynomial time. We give simple proofs that the same holds for depth-1 propositional calculus (where resolution has depth 0) with respect to mean payoff and simple stochastic games. We define a new type of combinatorial game and prove that resolution is weakly automatizable if and only if one can separate, by a set decidable in polynomial time, the games in which the first player has a positional winning strategy from the games in which the second player has a positional winning strategy. Our main technique is to show that a suitable weak bounded arithmetic theory proves that both players in a game cannot simultaneously have a winning strategy, and then to translate this proof into propositional form.
Approximate Inference for Observation-Driven Time Series Models with Intractable Likelihoods
Authors: Jasra Ajay , Kantas Nikolas , Ehrlich Elena
Published: May 2014

In this article, we consider approximate Bayesian parameter inference for observation-driven time series models. Such statistical models appear in a wide variety of applications, including econometrics and applied mathematics. This article considers the scenario where the likelihood function cannot be evaluated pointwise; in such cases, one cannot perform exact statistical inference, including parameter estimation, which often requires advanced computational algorithms, such as Markov Chain Monte Carlo (MCMC). We introduce a new approximation based upon Approximate Bayesian Computation (ABC). Under some conditions, we show that as
n
→ ∞, with
n
the length of the time series, the ABC posterior has, almost surely, a Maximum A Posteriori (MAP) estimator of the parameters that is often different from the true parameter. However, a noisy ABC MAP, which perturbs the original data, asymptotically converges to the true parameter, almost surely. In order to draw statistical inference, for the ABC approximation adopted, standard MCMC algorithms can have acceptance probabilities that fall at an exponential rate in
n
and slightly more advanced algorithms can mix poorly. We develop a new and improved MCMC kernel, which is based upon an exact approximation of a marginal algorithm, whose cost per iteration is random, but the expected cost, for good performance, is shown to be
O
(
n
2
) per iteration. We implement our new MCMC kernel for parameter inference from models in econometrics.
Sophisticated Access Control via SMT and Logical Frameworks
Authors: Arkoudas Konstantine , Chadha Ritu , Chiang Jason
Published: May 2014

We introduce a new methodology for formulating, analyzing, and applying access-control policies. Policies are expressed as formal theories in the SMT (satisfiability-modulo-theories) subset of typed first-order logic, and represented in a programmable logical framework, with each theory extending a core ontology of access control. We reduce both request evaluation and policy analysis to SMT solving, and provide experimental results demonstrating the practicality of these reductions. We also introduce a class of canonical requests and prove that such requests can be evaluated in linear time. In many application domains, access requests are either naturally canonical or can easily be put into canonical form. The resulting policy framework is more expressive than XACML and languages in the Datalog family, without compromising efficiency. Using the computational logic facilities of the framework, a wide range of sophisticated policy analyses (including consistency, coverage, observational equivalence, and change impact) receive succinct formulations whose correctness can be straightforwardly verified. The use of SMT solving allows us to efficiently analyze policies with complicated numeric (integer and real) constraints, a weak point of previous policy analysis systems. Further, by leveraging the programmability of the underlying logical framework, our system provides exceptionally flexible ways of resolving conflicts and composing policies. Specifically, we show that our system subsumes FIA (Fine-grained Integration Algebra), an algebra recently developed for the purpose of integrating complex policies.
A novel oral dual amylin and calcitonin receptor agonist (KBP-042) exerts antiobesity and antidiabetic effects in rats
Authors: Andreassen Kim V. , Feigh Michael , Hjuler Sara T. , Gydesen Sofie , Henriksen Jan Erik , Beck-Nielsen Henning , Christiansen Claus , Karsdal Morten A. , Henriksen Kim
Published: May 2014

The present study investigated a novel oral dual amylin and calcitonin receptor agonist (DACRA), KBP-042, in head-to-head comparison with salmon calcitonin (sCT) with regard to in vitro receptor pharmacology, ex vivo pancreatic islet studies, and in vivo proof of concept studies in diet-induced obese (DIO) and Zucker diabetic fatty (ZDF) rats. In vitro, KBP-042 demonstrated superior binding affinity and activation of amylin and calcitonin receptors, and ex vivo, KBP-042 exerted inhibitory action on stimulated insulin and glucagon release from isolated islets. In vivo, KBP-042 induced a superior and pronounced reduction in food intake in conjunction with a sustained pair-fed corrected weight loss in DIO rats. Concomitantly, KBP-042 improved glucose homeostasis and reduced hyperinsulinemia and hyperleptinemia in conjunction with enhanced insulin sensitivity. In ZDF rats, KBP-042 induced a superior attenuation of diabetic hyperglycemia and alleviated impaired glucose and insulin tolerance. Concomitantly, KBP-042 preserved insulinotropic and induced glucagonostatic action, ultimately preserving pancreatic insulin and glucagon content. In conclusion, oral KBP-042 is a novel DACRA, which exerts antiobesity and antidiabetic efficacy by dual modulation of insulin sensitivity and directly decelerating stress on the pancreatic α- and β-cells. These results could provide the basis for oral KBP-042 as a novel therapeutic agent in type 2 diabetes.
Insulin sensitivity is inversely related to cellular energy status, as revealed by biotin deprivation
Authors: Salvador-Adriano Ana , Vargas-Chávez Sonia , Hernández-Vázquez Alain de J. , Ortega-Cuellar Daniel , Tovar Armando R. , Velázquez-Arellano Antonio
Published: May 2014

We have reported an early decrease in glycemia in rats fed a biotin-deficient diet with reduced cellular ATP levels, suggesting increased insulin sensitivity. Here, we show that biotin-deprived rats are more tolerant of glucose, as shown by both oral and intraperitoneal glucose tolerance tests, during which insulin plasma levels were significantly diminished in deficient rats compared with controls. Biotin-deficient rats had lower blood glucose concentrations during intraperitoneal insulin sensitivity tests than controls. Furthermore, more glucose was infused to maintain euglycemia in the biotin-deficient rats during hyperinsulinemic euglycemic clamp studies. These results demonstrate augmented sensitivity to insulin in biotin-deprived rats. They are most likely the consequence of an insulin-independent effect of AMPK activation on GLUT4 membrane translocation with increased glucose uptake. In biotin-deficient cultured L6 muscle cells, there was increased phosphorylation of the energy sensor AMPK. We have now confirmed the augmented AMPK activation in both biotin-deprived in vivo muscle and cultured muscle cells. In these cells, glucose uptake is increased by AMPK activation by AICAR and diminished by its knockdown by the specific siRNAs directed against its α1- and α2-catalytic subunits, with all of these effects being largely independent of the activity of the insulin-signaling pathway that was inhibited with wortmannin. The enhanced insulin sensitivity in biotin deficiency likely has adaptive value for organisms due to the hormone promotion of uptake and utilization of not only glucose but other nutrients such as branched-chain amino acids, whose deficiency has been reported to increase insulin tolerance.
Identification of a novel phosphorylation site in adipose triglyceride lipase as a regulator of lipid droplet localization
Authors: Xie Xitao , Langlais Paul , Zhang Xiaodong , Heckmann Bradlee L. , Saarinen Alicia M. , Mandarino Lawrence J. , Liu Jun
Published: May 2014

Adipose triglyceride lipase (ATGL), the rate-limiting enzyme for triacylglycerol (TG) hydrolysis, has long been known to be a phosphoprotein. However, the potential phosphorylation events that are involved in the regulation of ATGL function remain incompletely defined. Here, using a combinatorial proteomics approach, we obtained evidence that at least eight different sites of ATGL can be phosphorylated in adipocytes. Among them, Thr372 resides within the hydrophobic region known to mediate lipid droplet (LD) targeting. Although it had no impact on the TG hydrolase activity, substitution of phosphorylation-mimic Asp for Thr372 eliminated LD localization and LD-degrading capacity of ATGL expressed in HeLa cells. In contrast, mutation of Thr372 to Ala gave a protein that bound LDs and functioned the same as the wild-type protein. In nonstimulated adipocytes, the Asp mutation led to decreased LD association and basal lipolytic activity of ATGL, whereas the Ala mutation produced opposite effects. Moreover, the LD translocation of ATGL upon β-adrenergic stimulation was also compromised by the Asp mutation. In accord with these findings, the Ala mutation promoted and the Asp mutation attenuated the capacity of ATGL to mediate lipolysis in adipocytes under both basal and stimulated conditions. Collectively, these studies identified Thr372 as a novel phosphorylation site that may play a critical role in determining subcellular distribution as well as lipolytic action of ATGL.
Sulforaphane reduction of testicular apoptotic cell death in diabetic mice is associated with the upregulation of Nrf2 expression and function
Authors: Wang Yonggang , Zhang Zhiguo , Guo Weiying , Sun Weixia , Miao Xiao , Wu Hao , Cong Xianling , Wintergerst Kupper A. , Kong Xiangbo , Cai Lu
Published: May 2014

Diabetes-induced testicular cell death is due predominantly to oxidative stress. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is an important transcription factor in controlling the antioxidative system and is inducible by sulforaphane (SFN). To test whether SFN prevents diabetes-induced testicular cell death, an insulin-defective stage of type 2 diabetes (IDS-T2DM) was induced in mice. This was accomplished by feeding them a high-fat diet (HFD) for 3 mo to induce insulin resistance and then giving one intraperitoneal injection of streptozotocin to induce hyperglycemia while age-matched control mice were fed a normal diet (ND). IDS-T2DM and ND-fed control mice were then further subdivided into those with or without 4-mo SFN treatment. IDS-T2DM induced significant increases in testicular cell death presumably through receptor and mitochondrial pathways, shown by increased ratio of Bax/Bcl2 expression and cleavage of caspase-3 and caspase-8 without significant change of endoplasmic reticulum stress. Diabetes also significantly increased testicular oxidative damage and inflammation. All of these diabetic effects were significantly prevented by SFN treatment with upregulated Nrf2 expression. These results suggest that IDS-T2DM induces testicular cell death presumably through caspase-8 activation and mitochondria-mediated cell death pathways and also by significantly downregulating testicular Nrf2 expression and function. SFN upregulates testicular Nrf2 expression and its target antioxidant expression, which was associated with significant protection of the testis from IDS-T2DM-induced germ cell death.