bluuebunny/crossref_metadata_2025 huggingface dataset:
Hot Extrusion of Thin-Wall Multichannel Copper Profiles
Authors: Kraft Frank F. , Kochis Jonathan
Published: September 2013

This paper presents the development of a unique, net shape, hot-extrusion process to produce precision, thin-wall, multichannel copper profiles for high efficiency heat-exchangers. This process is a departure from conventional copper extrusion, which is a nonisothermal process used primarily to produce simple semifinished products and hollow profiles requiring cold drawing after hot extrusion. A lab-scale apparatus was developed to simultaneously extrude multiple heated billets through a porthole type hollow die to form the multi-channel profiles. The process is performed at 700–750 °C, essentially at isothermal extrusion conditions. Temperature and tooling strength considerations necessitated the use of superalloys for the apparatus (which included dies, container, ram stems, and support tooling). A 250 kN computer controlled servo-hydraulic MTS® machine was used to provide the extrusion ram force. Two part designs were extruded to demonstrate process feasibility and versatility. A two-channel design with 0.2 mm wall thicknesses and an 11-channel design with wall-thicknesses of 0.3 mm were extruded. The extrusion ratios for these profiles are 67 and 25, respectively. Experimental data and an approach to analytically model the process are presented. Because solid-state welds in the tube walls are necessitated by the use of hollow extrusion dies, the microstructure in these regions is also presented.
Study of Droplet Spray Behavior of an Atomization-Based Cutting Fluid Spray System for Machining Titanium Alloys
Authors: Nath Chandra , Kapoor Shiv G. , Srivastava Anil K. , Iverson Jon
Published: September 2013

The atomization-based cutting fluid (ACF) spray system has been found to be effective for improving the tool life and overall productivity during the machining of titanium alloys like Ti–6Al–4 V. The aim of this research is to study droplet spray characteristics of an ACF spray system including droplet entrainment zone (e.g., angle and distance) and droplet-gas co-flow development regions with respect to three ACF spray parameters, viz., droplet and gas velocities, and spray distance. ACF spray experiments are performed by varying droplet and gas velocities. Machining experiments are performed in order to understand the effect of the droplet spray behavior on the machining performance, viz., tool life/wear, and surface roughness during turning of a titanium alloy, Ti–6Al–4 V. The flow development behavior with respect to the spray distance is studied by modeling the droplets entrainment mechanism. The model is validated by the ACF spray experiments. Experiments and the modeling of flow development behavior reveal that a higher droplet velocity and a smaller gas velocity result in smaller droplet entrainment angle leading to a gradual and early development of the co-flow, and a better distribution of the droplets across the jet flare. Machining experiments also show that a higher droplet velocity, a lower gas velocity and a longer spray distance significantly improve tool life and surface finish.
New Discharge Coefficient of Throat Tap Nozzle Based on ASME Performance Test Code 6 for Reynolds Number From 2.4 × 105 to 1.4 × 107
Authors: Furuichi Noriyuki , Cheong Kar-Hooi , Terao Yoshiya , Nakao Shinichi , Fujita Keiji , Shibuya Kazuo
Published: September 2013

The throat tap nozzle of the American Society of Mechanical Engineers performance test code (ASME PTC) 6 is widely used in engineering fields, and its discharge coefficient is normally estimated by an extrapolation in Reynolds number range higher than the order of 107. The purpose of this paper is to propose a new relation between the discharge coefficient of the throat tap nozzle and Reynolds number by a detailed analysis of the experimental data and the theoretical models, which can be applied to Reynolds numbers up to 1.5 × 107. The discharge coefficients are measured for several tap diameters in Reynolds numbers ranging from 2.4 × 105 to 1.4 × 107 using the high Reynolds number calibration rig of the National Metrology Institute of Japan (NMIJ). Experimental results show that the discharge coefficients depend on the tap diameter and the deviation between the experimental results and the reference curve of PTC 6 is 0.75% at maximum. New equations to estimate the discharge coefficient are developed based on the experimental results and the theoretical equations including the tap effects. The developed equations estimate the discharge coefficient of the present experimental data within 0.21%, and they are expected to estimate more accurately the discharge coefficient of the throat tap nozzle of PTC 6 than the reference curve of PTC 6.
A Contribution to Improve the Accuracy of Chatter Prediction in Machine Tools Using the Stability Lobe Diagram
Authors: Galdino dos Santos Raphael , Teixeira Coelho Reginaldo
Published: September 2013

The chatter phenomenon can severely limit the power available for milling. The stability lobe diagram (SLD) is a very fast and simple method to predict the chatter free zone, allowing the selection of the most adequate spindle speed and depth of cut for higher productivity. However, the data used to calculate the SLD, coming from frequency response functions (FRFs), must be acquired adequately to improve the predictability. FRFs result differently depending on the activation of the spindle electronic control. The present work uses SLDs to investigate these differences and experimental end milling tests to assess the accuracy of SLDs curves. Results indicate that the inclusion of spindle electronic control provides better accuracy in predicting the chatter in milling.
Solving Thermal Issues in a Three-Dimensional-Stacked-Quad-Core Processor by Microprocessor Floor Planning, Microchannel Cooling, and Insertion of Through-Silicon-Vias
Authors: Chauhan Anjali , Sammakia Bahgat , Afram Furat F. , Ghose Kanad , Refai-Ahmed Gamal , Agonafer Dereje
Published: September 2013

The electronics industry is heading toward the three-dimensional (3D) microprocessor to cope with higher computing workloads. The 3D stacking of the processor and the memory components reduces the communication delay in multicore system-on-a-chip (SoCs), owing to reduced system size and shorter interconnects. The shorter interconnects in a multicore system lowers the memory access latencies and contributes to improvements in memory access bandwidth. The shorter interconnects in stacked architectures also enables small drivers for interconnections which further reduce interconnection-level-energy dissipations. On the down side, the 3D-stacked architectures have high thermal resistance, which in conjunction with poor thermal management techniques, poses a thermal threat to the reliability of the device. This paper establishes the significance of the microprocessor floor planning and single-phase microchannel cooling for solving the thermal issues arising in the 3D-stacked-quad-core processor. The 3D-stacked-quad-core processor considered in this study comprises of symmetric nonuniformly powered quad-core processor, liquid-cooled microchannel heat sink, dynamic random access memory (DRAM), thermal interface material (TIM), and heat spreader. The electrical through-silicon-vias (TSVs) between the processor and DRAM serve as interconnects, while the thermal TSVs reduce the internal thermal resistance. The effective cooling of the 3D-stacked-quad-core processor depends on the TSVs, quad-core layout and the optimized design of the microchannel heat sink for the desired coolant. The microchannel cooling of the 3D-stacked processor is done both by planar flow and impingement flow. The thermal efficiency of the cooling techniques is evaluated on the basis of hot spot temperature, hot spot spread, and number of hot spots.
Simulation of Static Performance of Air Foil Bearings Using Coupled Finite Element and Computational Fluid Dynamics Techniques
Authors: Paouris Leonidas I. , Bompos Dimitrios A. , Nikolakopoulos Pantelis G.
Published: September 2013

The main objective of the current work is to determine a relationship between the top and bump foil's geometry and load-carrying capacity in a journal compliant generation I air foil bearing, as well as determining the effect of the thermohydrodynamic phenomena in the performance of the air foil bearing (AFB). Static and steady-state operation is assumed throughout the analysis. A finite element model is adopted in order to investigate the operational characteristics of the specific bearing. Bump foil's elastic behavior is modeled using two node linear link spring elements. During the hydrodynamic analysis, incompressible viscous steady state Navier–Stokes equations are numerically solved, due to the low bearing compressibility number. During the thermohydrodynamic analysis, compressible, viscous, steady-state Navier–Stokes equations were solved, coupled with the energy equation. The material used during the structural analysis is Inconel X750, and it is assumed that it has linear and elastic behavior. Constant ambient pressure is applied at the free faces of the fluid as well as no slip condition at the surface of the fluid that faces the top foil. Computational fluid dynamics (CFD) and structural models are solved separately. At the beginning of the analysis, the CFD problem is solved with the assumption that the top foil has not yet been deformed. After the solution of the CFD problem, the pressure distribution at the surface of the fluid that faces the top foil is applied at the top foil and then the structural problem is solved. Consequently, the deflections of the top foil are applied on the corresponding surface of the CFD model and the algorithm continues until convergence is obtained. As soon as the converged solution for the pressure distribution is obtained, numerical integration is performed along the surface of the bearing in order to calculate its load-carrying capacity. Static bearing performance characteristics, such as pressure distribution, bump foil deflection, and load capacity are calculated and presented. Furthermore, fluid film thickness, top foil deflection, and fluid pressure are investigated as functions of the bearing angle as well as load-carrying capacity as a function of the bump and top foil stiffness. The same procedure is repeated for the thermohydrodynamic analysis. Moreover, in order to estimate the heat flux from the top foil to the bump foil channel as a function of the top foil temperature, a simple finite element model of the bump foil–cooling channel is constructed.
Bypass Mechanisms of Resistance to Receptor Tyrosine Kinase Inhibition in Lung Cancer
Authors: Niederst Matthew J. , Engelman Jeffrey A.
Published: September 2013

The mechanisms mediating kinase inhibitor resistance in lung cancer are reviewed.
CCR5-Maraviroc Structure
Authors: Pickersgill Helen
Published: September 2013

The crystal structure of the HIV co-receptor CCR5 bound to the HIV drug maraviroc provides insight into how HIV enters cells.
Stealth Nod Factor Recognition
Authors: Hines Pamela
Published: September 2013

Nitrogen-fixing bacteria dampen immune responses in their plant hosts.
Amyloid Binding Partners
Authors: Hines Pamela
Published: September 2013

A potential β-amyloid receptor in neurons regulates ocular dominance in mouse brain development.
Generation of Effector Memory T Cell–Based Mucosal and Systemic Immunity with Pulmonary Nanoparticle Vaccination
Authors: Li Adrienne V. , Moon James J. , Abraham Wuhbet , Suh Heikyung , Elkhader Jamal , Seidman Michael A. , Yen Minmin , Im Eung-Jun , Foley Maria H. , Barouch Dan H. , Irvine Darrell J.
Published: September 2013

A lipid nanocapsule vaccine promotes cross-presentation of antigen with enhanced draining lymph node delivery to elicit an effector memory CD8
+
T cell response.
Response to Comment on “Community-Wide Isoniazid Preventive Therapy Drives Drug-Resistant Tuberculosis: A Model-Based Analysis”
Authors: Mills Harriet L. , Cohen Ted , Colijn Caroline
Published: September 2013

Our modeling work suggests that isoniazid preventive therapy (IPT) can be effective in reducing drug-sensitive tuberculosis (TB) and that the risk of IPT driving resistance can be reduced by improving the detection and rapid treatment of individuals with drug-resistant disease and by limiting IPT to those in whom the intervention will have the largest benefit.
Human Skin in the Game
Authors: Clark Rachael A.
Published: September 2013

Clinical and experimental observations in atopic dermatitis and psoriasis reveal new mechanisms of inflammation and antiviral immunity.
Vaccine Economics: What Price Human Life?
Authors: Mekalanos John J.
Published: September 2013

The recent decision not to recommend a new vaccine that protects against meningococcal B disease prioritizes health care in economic rather than humanistic terms.
Big Genes Cause Big Problems
Authors: Gregg Christopher
Published: September 2013

Topoisomerases facilitate the transcription of long genes, including many that contribute to autism spectrum disorders.
An Association Between Peptidoglycan Synthesis and Organization of the Streptococcus pyogenes ExPortal
Authors: Vega Luis Alberto , Port Gary C. , Caparon Michael G.
Published: September 2013

The ExPortal of
Streptococcus pyogenes
is a focal microdomain of the cytoplasmic membrane that clusters the translocons of the general secretory pathway with accessory factors to facilitate the maturation of secreted polypeptides. While it is known that the ExPortal is enriched in anionic lipids, the mechanisms that organize the ExPortal are poorly understood. In the present study, we examined the role of the cell wall in organizing and maintaining the ExPortal. Removal of the cell wall resulted in a loss of ExPortal focal integrity accompanied by the circumferential redistribution of ExPortal lipid and protein components. A similar loss occurred upon treatment with gallidermin, a nonpermeabilizing lantibiotic that targets the lipid II precursor of peptidoglycan synthesis, and this treatment disrupted the secretion of several ExPortal substrates. Furthermore, several enzymes involved in the membrane-associated steps of lipid II synthesis, including MraY and MurN, were found to localize to a single discrete focus in the membrane that was coincident with the focal location of the secretory translocons and the anionic lipid microdomain. These data suggest that the ExPortal is associated with the site of peptidoglycan precursor synthesis and that peptidoglycan biogenesis influences ExPortal organization. These data add to an emerging literature indicating that cell wall biogenesis, cell division, and protein secretion are spatially coorganized processes.

IMPORTANCE
Since Gram-positive bacteria lack a periplasmic space, they lack a protected compartment to spatially coordinate interaction between newly secreted proteins and the factors required to process them. This represents a significant problem for pathogens that depend on the secretion of toxins and cell wall-associated adhesins to cause disease. Streptococci solve this dilemma by restricting secretion and processing factors to a defined region of the membrane. However, the mechanisms that promote restriction are not understood. In this study, we show that restriction of these factors in the pathogen
Streptococcus pyogenes
is intimately linked with the presence of the cell wall and its synthesis. Furthermore, several cell wall synthesis proteins are also restricted to the site of protein secretion. This study contributes to our understanding of how the Gram-positive cell is organized to coordinate protein secretion and biogenesis with cell wall synthesis and to the ongoing development of antibiotics that target these processes.
Basal Levels of (p)ppGpp in Enterococcus faecalis: the Magic beyond the Stringent Response
Authors: Gaca Anthony O. , Kajfasz Jessica K. , Miller James H. , Liu Kuanqing , Wang Jue D. , Abranches Jacqueline , Lemos José A.
Published: September 2013

The stringent response (SR), mediated by the alarmone (p)ppGpp, is a conserved bacterial adaptation system controlling broad metabolic alterations necessary for survival under adverse conditions. In
Enterococcus faecalis
, production of (p)ppGpp is controlled by the bifunctional protein RSH (for “Rel SpoT homologue”; also known as RelA) and by the monofunctional synthetase RelQ. Previous characterization of
E. faecalis
strains lacking
rsh
,
relQ
, or both revealed that RSH is responsible for activation of the SR and that alterations in (p)ppGpp production negatively impact bacterial stress survival and virulence. Despite its well-characterized role as the effector of the SR, the significance of (p)ppGpp during balanced growth remains poorly understood. Microarrays of
E. faecalis
strains producing different basal amounts of (p)ppGpp identified several genes and pathways regulated by modest changes in (p)ppGpp. Notably, expression of numerous genes involved in energy generation were induced in the ∆
rsh
∆
relQ
[(p)ppGpp
0
] strain, suggesting that a lack of basal (p)ppGpp places the cell in a “transcriptionally relaxed” state. Alterations in the fermentation profile and increased production of H
2
O
2
in the (p)ppGpp
0
strain substantiate the observed transcriptional changes. We confirm that, similar to what is seen in
Bacillus subtilis
, (p)ppGpp directly inhibits the activity of enzymes involved in GTP biosynthesis, and complete loss of (p)ppGpp leads to dysregulation of GTP homeostasis. Finally, we show that the association of (p)ppGpp with antibiotic survival does not relate to the SR but rather relates to basal (p)ppGpp pools. Collectively, this study highlights the critical but still underappreciated role of basal (p)ppGpp pools under balanced growth conditions.

IMPORTANCE
Drug-resistant bacterial infections continue to pose a significant public health threat by limiting therapeutic options available to care providers. The stringent response (SR), mediated by the accumulation of two modified guanine nucleotides collectively known as (p)ppGpp, is a highly conserved stress response that broadly remodels bacterial physiology to a survival state. Given the strong correlation of the SR with the ability of bacteria to survive antibiotic treatment and the direct association of (p)ppGpp production with bacterial infectivity, understanding how bacteria produce and utilize (p)ppGpp may reveal potential targets for the development of new antimicrobial therapies. Using the multidrug-resistant pathogen
Enterococcus faecalis
as a model, we show that small alterations to (p)ppGpp levels, well below concentrations needed to trigger the SR, severely affected bacterial metabolism and antibiotic survival. Our findings highlight the often-underappreciated contribution of basal (p)ppGpp levels to metabolic balance and stress tolerance in bacteria.
Opportunistic pathology-based screening for diabetes
Authors: Simpson Aaron J , Krowka Renata , Kerrigan Jennifer L , Southcott Emma K , Wilson J Dennis , Potter Julia M , Nolan Christopher J , Hickman Peter E
Published: September 2013

Objective

To determine the potential of opportunistic glycated haemoglobin (HbA1c) testing of pathology samples to detect previously unknown diabetes.

Design

Pathology samples from participants collected for other reasons and suitable for HbA1c testing were utilised for opportunistic diabetes screening. HbA1c was measured with a Biorad Variant II turbo analyser and HbA1c levels of ≥6.5% (48 mmol/mol) were considered diagnostic for diabetes. Confirmation of previously unknown diabetes status was obtained by a review of hospital medical records and phone calls to general practitioners.

Setting

Hospital pathology laboratory receiving samples from hospital-based and community-based (CB) settings.

Participants

Participants were identified based on the blood sample collection location in the CB, emergency department (ED) and inpatient (IP) groups. Exclusions pretesting were made based on the electronic patient history of: age <18 years, previous diabetes diagnosis, query for diabetes status in the past 12 months, evidence of pregnancy and sample collected postsurgery or transfusion. Only one sample per individual participant was tested.

Results

Of the 22 396 blood samples collected, 4505 (1142 CB, 1113 ED, 2250 IP) were tested of which 327 (7.3%) had HbA1c levels ≥6.5% (48 mmol/mol). Of these 120 (2.7%) were determined to have previously unknown diabetes (11 (1%) CB, 21 (1.9%) ED, 88 (3.9%) IP). The prevalence of previously unknown diabetes was substantially higher (5.4%) in hospital-based (ED and IP) participants aged over 54 years.

Conclusions

Opportunistic testing of referred pathology samples can be an effective method of screening for diabetes, especially in hospital-based and older persons.
Measuring a caring culture in hospitals: a systematic review of instruments
Authors: Hesselink G , Kuis E , Pijnenburg M , Wollersheim H
Published: September 2013

Objective

To identify instruments or components of instruments that aim to measure aspects of a caring culture-shared beliefs, norms and values that direct professionals and managers to act caring in hospitals, and to evaluate their psychometric properties.

Design

Systematic review.

Data sources

PubMed, CINAHL, EMBASE, PsychInfo, Web of Science and the International bibliography of the Social Sciences.

Study selection

Peer-reviewed articles describing (components of) instruments measuring aspects of a caring culture in a hospital setting. Studies had to report psychometric data regarding the reliability or validity of the instrument. Potentially useful instruments that were identified after the title and abstract scan were assessed on relevance by an expert panel (n=12) using the RAND-modified Delphi procedure.

Results

Of the 6399 references identified, 75 were examined in detail. 7 studies each covering a unique instrument met our inclusion criteria. On average, 24% of the instrument's items were considered relevant for measuring aspects of the hospital's caring culture. Studies showed moderate-to-high validity and reliability scores. Validity was addressed for 6 of the 7 instruments. Face, content (90%) and construct (60%) validity were the most frequently reported psychometric properties described. One study (14%) reported discriminant validity of the instrument. Reliability data were available for all of the instruments. Internal consistency was the most frequently reported psychometric property for the instruments and demonstrated by: a Cronbach's α coefficient (80%), subscale intercorrelations (60%), and item–total correlations (40%).

Conclusions

The ultimate standard for measuring a caring culture in hospitals does not exist. Existing instruments provide partial coverage and lack information on discriminant validity, responsiveness and feasibility. Characteristics of the instruments included in this review could provide useful input for the design of a reliable and valid instrument for measuring a caring culture in hospitals.
Trends in age at first hospital admission in relation to trends in life expectancy in Swedish men and women above the age of 60
Authors: Karampampa Korinna , Drefahl Sven , Andersson Tomas , Ahlbom Anders , Modig Karin
Published: September 2013

Objectives

To examine whether the first admission to hospital after the age of 60 has been postponed to higher ages for men and women in Sweden, in line with the shift in mortality.

Design

This nationwide observational study was based on data obtained from national registries in Sweden. The study cohort was created by linking the Register of the Total Population in Sweden with the National Patient Register and the Swedish Cause of Death Register.

Setting

The entire Swedish population born between 1895 and 1950 was followed up between 1987 and 2010 with respect to hospital admissions and deaths using the national registry data.

Primary outcome measures

The time from age 60 until the first admission to the hospital, regardless of the diagnosis, and the time from age 60 until death (remaining life expectancy, LE) were estimated for the years 1995–2010. The difference between these two measures was also estimated for the same period.

Results

Between 1995 and 2010 mortality as well as first hospital admission shifted to higher ages. The average time from age 60, 70, 80 and 90 until the first hospital admission increased at all ages. The remaining LE at age 60, 70 and 80 increased for men and women. For the 90-year-olds it was stable.

Conclusions

In Sweden, the first hospital admission after the age of 60 has been pushed to higher ages in line with mortality for the ages 60 and above. First admission to the hospital could indicate the onset of first severe morbidity; however, the reorganisation of healthcare may also have influenced the observed trends.
‘Do As We Say, Not as We Do:’ a cross-sectional survey of injuries in injury prevention professionals
Authors: Ezzat Allison , Brussoni Mariana , Schneeberg Amy , Jones Sarah J
Published: September 2013

Background

As the leading cause of death and among the top causes of hospitalisation in Canadians aged 1–44 years, injury is a major public health concern. Little is known about whether knowledge, training and understanding of the underlying causes and mechanisms of injury would help with one's own prevention efforts. Based on the Theory of Planned Behaviour, we hypothesised that injury prevention professionals would experience fewer injuries than the general population.

Methods

An online cross-sectional survey was distributed to Canadian injury prevention practitioners, researchers and policy makers to collect information on medically attended injuries. Relative risk of injury in the past 12 months was calculated by comparing the survey data with injury incidence reported by a comparable subgroup of adults from the (Canadian Community Health Survey (CCHS)) from 2009 to 2010.

Results

We had 408 injury prevention professionals complete the survey: 344 (84.5%) women and 63 (15.5%) men. In the previous 12 months, 86 individuals reported experiencing at least one medically attended injury (21 235 people per 100 000 people); with sports being the most common mechanism (41, 33.6%). Fully 84.8% individuals from our sample believed that working in the field had made them more careful. After accounting for age distribution, education level and employment status, injury prevention professionals were 1.69 (95% CI 1.41 to 2.03) times more likely to be injured in the past year.

Interpretation

Despite their convictions of increasing their own safety behaviour and that of others, injury prevention professionals’ knowledge and training did not help them prevent their own injuries.
Income inequality among American states and the incidence of major depression
Authors: Pabayo Roman , Kawachi Ichiro , Gilman Stephen E
Published: September 2013

Background

Although cross-sectional and ecological studies have shown that higher area-level income inequality is related to increased risk for depression, few longitudinal studies have been conducted. This investigation examines the relationship between state-level income inequality and major depression among adults participating in a population-based, representative longitudinal study.

Methods

We used data from the National Epidemiologic Survey on Alcohol and Related Conditions (n=34 653). Respondents completed structured diagnostic interviews at baseline (2001–2002) and follow-up (2004–2005). Weighted multilevel modelling was used to determine if US state-level income inequality (measured by the Gini coefficient) was a significant predictor of depression at baseline and at follow-up, while controlling for individual-level and state-level covariates. We also repeated the longitudinal analyses, excluding those who had a history of depression or at baseline, in order to test whether income inequality was related to incident depression.

Results

State-level inequality was associated with increased incidence of depression among women but not men. In comparison to women residing in states belonging to the lowest quintile of income inequality, women were at increased risk for depression in the second (OR=1.18, 95% CI 0.86 to 1.62), third (OR=1.22, 95% CI 0.91 to 1.62), fourth (OR=1.37, 95% CI 1.03 to 1.82) and fifth (OR=1.50, 95% CI 1.14 to 1.96) quintiles at follow-up (p<0.05 for the linear trend).

Conclusions

Living in a state with higher income inequality increases the risk for the development of depression among women.
Delayed ischemic stroke following spontaneous thrombosis of an arteriovenous malformation
Authors: Shah Ashish Harish , Haussen Diogo C , Snelling Brian M , Heros Roberto C , Yavagal Dileep R
Published: September 2013

Spontaneous obliteration of an arteriovenous malformation (SOAVM) is a rare event that is not completely understood. Less than 100 cases of SOAVMs have been reported in the literature. We present a unique case of a middle-aged patient with spontaneous obliteration of a cerebral arteriovenous malformation (AVM) who developed an ischemic stroke due to thrombosis of the stagnant proximal segment of the inferior branch of the middle cerebral artery feeder. Although the pathophysiology is not well understood, the arterial feeder hemodynamic changes post SOAVM may behave similarly to what occurs in rare cases after surgical resection of AVMs. Our case raises the hypothesis that stagnation of flow in spontaneous AVM obliteration may lead to delayed ischemic stroke in the territory of the feeding artery.
Effect of load shape on relationship between dissipated energy and residual excess pore pressure generation in cyclic triaxial tests
Authors: Polito Carmine , Green Russell A. , Dillon Erin , Sohn Changbum
Published: September 2013

The energy dissipated in soil during cyclic loading can be used to predict the change in the pore-water pressure developed in the soil. To examine whether the energy required to cause liquefaction is dependent on or independent of the load shape applied, a series of 28 cyclic triaxial tests were performed using five different load shapes having a range of cyclic stress ratios. The five load shapes were applied to identically prepared specimens of clean sand and the dissipated energy – pore pressure generation characteristics examined. It was found that that the dissipated energy to cause initial liquefaction was normally distributed and independent of the load shape, although it is seemingly somewhat dependent on duration of loading. A corollary to this finding is that laboratory data from specimens tested using sinusoidal loadings can be used to calibrate the Green, Mitchell, and Polito (GMP) energy-based pore pressure generation model for use in predicting in situ pore pressures in soils subjected to nonsinusoidal loadings (e.g., earthquake loadings). Given the relative simplicity of the GMP model, these findings make the model an attractive alternative to implement in effective stress dynamic response codes.
Creep behavior in Virginia Beach sand
Authors: Karimpour Hamid , Lade Poul V.
Published: September 2013

Triaxial compression tests were performed on dense specimens of Virginia Beach sand at low and high confining pressures to study time effects that relate to grain crushing due to static fatigue or delayed fracture. Experiments to study effects of loading strain rate on subsequent creep showed negligible time effects and no grain crushing at low confining pressures, while tests at high confining pressures indicated increasing amounts of creep with increasing initial loading strain rates and with increasing deviator stress at creep. Investigation of effects of grain-size distribution indicated stiffer initial response and smaller amounts of creep for more uniformly graded soils at high confining pressures. The experimental results showed that structuration effects were not present in the dense Virginia Beach sand. A long-term creep test at high confining pressure indicated continuous creep with no indication of its termination. Sieve analyses following each triaxial test showed that grain crushing, as quantified by Hardin’s relative breakage factor, was proportional to energy input and amount of creep observed for each soil specimen. The creep is due to the time-dependent static fatigue by which the grains crush and cause rearrangement of the grain structure, and this is the reason behind the time effects in granular materials.
Axial compressive capacity of helical piles from field tests and numerical study
Authors: Elsherbiny Zeyad H. , El Naggar M. Hesham
Published: September 2013

The compressive capacity of helical piles in sand and clay is investigated by means of field testing and numerical modeling. The numerical models are conducted using the computer program ABAQUS and are calibrated and verified using full-scale load testing data. The calibration was accomplished by using reasonable assumptions regarding soil–pile interaction and soil parameters reported from the literature. The model was verified by comparing its predictions with observed load–displacement curves obtained from full-scale pile load tests. The verified numerical model was used to perform a parametric study considering different pile configurations and soil parameters to evaluate the compressive capacity and load-transfer mechanism of helical piles. The compressive capacity obtained from the numerical models is compared with that obtained from existing theoretical methods for calculating the capacity. It is found that the predictions of theoretical equations for piles in cohesionless soil vary largely depending on the choice of bearing capacity factors and proper failure criteria. The interaction of closely spaced helices on the capacity of a helical pile is also evaluated. A bearing capacity reduction factor, R, and helix efficiency factor, EH, are proposed to evaluate the compressive capacity of helical piles in cohesionless soil considering an industry-acceptable ultimate load criterion corresponding to settlement equal to 5% of helix diameter, D.
THE PAMELA COSMIC RAY SPACE OBSERVATORY
Authors:   on behalf of the PAMELA Collaboration, CASOLINO MARCO
Published: September 2013

PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV–700 GeV, electrons 50 MeV–400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV–190 GeV), positrons (50 MeV–270 GeV) and search for antimatter with a precision of the order of 10-8). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, 15 2006 in a 350 × 600 km orbit with an inclination of 70 degrees. The detector is composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, Time-of-Flight and rigidity information. Lepton/hadron identification is performed by a Silicon-Tungsten calorimeter and a Neutron detector placed at the bottom of the device. An Anticounter system is used offline to reject false triggers coming from the satellite. In self-trigger mode the Calorimeter, the neutron detector and a shower tail catcher are capable of an independent measure of the lepton component up to 2 TeV. In this work we present some of its scientific results in its first five years of operation.
ARGO-YBJ: A MULTI-PURPOSE EXPERIMENT OPERATION FOR 5 YEARS
Authors:   on behalf of the ARGO-YBJ and LHAASO Collaborations, CAO ZHEN
Published: September 2013

The ARGO-YBJ experiment has been smoothly operated for 5 years and has achieved many scientific goals. Here, we summarize all the major contributions and report them to the community. A future experiment LHAASO is proposed. It will greatly enhance the capabilities in both gamma ray astronomy and cosmic ray research.
EMG AMPLITUDE ESTIMATORS BASED ON PROBABILITY DISTRIBUTION FOR MUSCLE–COMPUTER INTERFACE
Authors: PHINYOMARK ANGKOON , QUAINE FRANCK , LAURILLAU YANN , THONGPANJA SIRINEE , LIMSAKUL CHUSAK , PHUKPATTARANONT PORNCHAI
Published: September 2013

To develop an advanced muscle–computer interface (MCI) based on surface electromyography (EMG) signal, the amplitude estimations of muscle activities, i.e., root mean square (RMS) and mean absolute value (MAV) are widely used as a convenient and accurate input for a recognition system. Their classification performance is comparable to advanced and high computational time-scale methods, i.e., the wavelet transform. However, the signal-to-noise-ratio (SNR) performance of RMS and MAV depends on a probability density function (PDF) of EMG signals, i.e., Gaussian or Laplacian. The PDF of upper-limb motions associated with EMG signals is still not clear, especially for dynamic muscle contraction. In this paper, the EMG PDF is investigated based on surface EMG recorded during finger, hand, wrist and forearm motions. The results show that on average the experimental EMG PDF is closer to a Laplacian density, particularly for male subject and flexor muscle. For the amplitude estimation, MAV has a higher SNR, defined as the mean feature divided by its fluctuation, than RMS. Due to a same discrimination of RMS and MAV in feature space, MAV is recommended to be used as a suitable EMG amplitude estimator for EMG-based MCIs.
Valanginian isotopic and palaeoecological signals from the Bucegi Mountains, Southern Carpathians, Romania
Authors: Barbu Victor
Published: September 2013

The first carbon- and oxygen-isotope records from the Valanginian to earliest Hauterivian (Early Cretaceous) in the Southern Carpathians, Bucegi Mountains (Romania), are discussed. Stable-isotope (δ
13
C
carb
, δ
18
O
carb
) curves from bulk sedimentary carbonate have been generated from three sections. δ
13
C
carb
values fluctuate between 2.1 and 2.7‰ within the late Early Valanginian (middle NK3A–base NK3B Calcareous Nannofossil Subzone, that corresponds to late
B
.
campylotoxus
–early
S
.
Verrucosum
Ammonite Zone), and between 1.1 and 1.7‰ within the Late Valanginian–earliest Hauterivian (NK3B–base NC4A Calcareous Nannofossil Subzone, that corresponds to ? uppermost
S
.
verrucosum
–
N
.
peregrinus
–
C
.
furcillata
–earliest
Acanthodiscus radius
Ammonite Zone). The total organic carbon (loss on ignition method (LOI)) content fluctuates between 1.6 and 2.8% within the late Early Valanginian, and from 0.6 to 3.3% within the Late Valanginian–earliest Hauterivian. These results suggest the presence of Valanginian organic-rich deposition and a concurrent positive δ
13
C
carb
excursion, which has been interpreted to represent an increase in surface water productivity. The abundance of the nannofossils,
Biscutum constans
,
Discorhabdus rotatorius
,
Zeugrhabdotus erectus
and
Diazomatolithus lehmanii
suggest higher fertility and eutrophic conditions. Low oxygenation conditions leading to organic matter preservation are suggested by the presence of conical and trochospiral inflated benthic foraminiferal specimens. Furthermore, bottom-water dysaerobic conditions are suggested by the dominance of small
Spirillina
.

High fertility in the ocean could be related to a rise in atmospheric
p
CO2 levels, globally linked to the formation of the Paranà–Etendeka continental flood basalts and increased rates of oceanic crust production. Moreover, the palaeoenvironmental changes represented in the Southern Carpathians coincides with the initiation of carbonate platform drowning, as recorded globally in many sections.
A Microbial Fuel Cell Anode Model Applying Irreversible Thermodynamiics
Authors: Velez Juan Esteban , Sanchez Carlos
Published: September 2013

The electrical energy generation from biodegradable waste, has been gainingground due the growing demand of this resource and the environmental impactassociated. The latter creates a paradox, from one side we have the satisfaction of theenergy demand, in other hand we create a problem that in long term could be worst, forexample the contamination of the soil, air and water by the use of toxic products(petroleum, carbon, uranium, etc.) in order to satisfy the growing demand. In that way themicrobial fuel cells, try to solve both problems at the same time, generating electricalenergy by oxidation of waste water and treat it in the process, reducing the organicloading (8). However, this technology is far from be perfect, because of the low powergeneration, that is not near to satisfy the actual energy demand. This work is looking tomodel the anode of a MFC from thermodynamics of irreversible process theory thisbecause of the need to taking account the fluxes and forces behind the behavior showedby these devices that arise from the two thermodynamic laws, in order to theorize aboutthis phenomena and to define the most appropriate parameters that make possible anoptimal performance. The main goal of this work is to open a new methodology of designMFC to treat the water of streams in the metropolitan area of Medellin, emphasizing inthe improvement of the power level of the cell.
Altered body composition and energy expenditure but normal glucose tolerance among humans with a long-chain fatty acid oxidation disorder
Authors: Gillingham Melanie B. , Harding Cary O. , Schoeller Dale A. , Matern Dietrich , Purnell Jonathan Q.
Published: September 2013

The development of insulin resistance has been associated with impaired mitochondrial fatty acid oxidation (FAO), but the exact relationship between FAO capacity and glucose metabolism continues to be debated. To address this controversy, patients with long-chain 3-hydroxy acyl-CoA dehydrogenase (LCHAD) deficiency underwent an oral glucose tolerance test (OGTT) and measurement of energy expenditure, body composition, and plasma metabolites. Compared with controls, patients with LCHAD deficiency had a trend toward higher total body fat and extramyocellular lipid deposition but similar levels of intramyocelluar and intrahepatic lipids. Resting energy expenditure was similar between the groups, but respiratory quotient was higher and total energy expenditure was lower in LCHAD-deficient patients compared with controls. High-molecular-weight (HMW) adiponectin levels were lower and plasma long-chain acylcarnitines were higher among LCHAD-deficient patients. Fasting and post-OGTT levels of glucose, insulin, and ghrelin, along with estimates of insulin sensitivity, were the same between the groups. Despite decreased capacity for FAO, lower total energy expenditure and plasma HMW adiponectin, and increased plasma acylcarnitines, LCHAD-deficient patients exhibited normal glucose tolerance. These data suggest that inhibition of the FAO pathway in humans is not sufficient to induce insulin resistance.
Constructing stem cell microenvironments using bioengineering approaches
Authors: Brafman David A.
Published: September 2013

Within the adult organism, stem cells reside in defined anatomical microenvironments called niches. These architecturally diverse microenvironments serve to balance stem cell self-renewal and differentiation. Proper regulation of this balance is instrumental to tissue repair and homeostasis, and any imbalance can potentially lead to diseases such as cancer. Within each of these microenvironments, a myriad of chemical and physical stimuli interact in a complex (synergistic or antagonistic) manner to tightly regulate stem cell fate. The in vitro replication of these in vivo microenvironments will be necessary for the application of stem cells for disease modeling, drug discovery, and regenerative medicine purposes. However, traditional reductionist approaches have only led to the generation of cell culture methods that poorly recapitulate the in vivo microenvironment. To that end, novel engineering and systems biology approaches have allowed for the investigation of the biological and mechanical stimuli that govern stem cell fate. In this review, the application of these technologies for the dissection of stem cell microenvironments will be analyzed. Moreover, the use of these engineering approaches to construct in vitro stem cell microenvironments that precisely control stem cell fate and function will be reviewed. Finally, the emerging trend of using high-throughput, combinatorial methods for the stepwise engineering of stem cell microenvironments will be explored.
Pancreastatin is an endogenous peptide that regulates glucose homeostasis
Authors: Valicherla Guru Raghavendra , Hossain Zakir , Mahata Sushil K. , Gayen Jiaur R.
Published: September 2013

Pancreastatin (PST) is a regulatory peptide containing 49 amino acids, first isolated from porcine pancreas. Intracellular and extracellular processing of the prohormone Chromogranin A (Chga) results various bioactive peptides of which PST has dysglycemic activity. PST regulates glucose, lipid, and protein metabolism in liver and adipose tissues. It also regulates the secretion of leptin and expression of leptin and uncoupling protein 2 in adipose tissue. In Chga knockout mice, PST induces gluconeogenesis in the liver. PST reduces glucose uptake in mice hepatocytes and adipocytes. In rat hepatocytes, PST induces glycogenolysis and glycolysis and inhibits glycogen synthesis. In rat adipocytes, PST inhibits lactate production and lipogenesis. These metabolic effects are confirmed in humans. In the dual signaling mechanism of PST receptor, mostly PST activates Gαq/11protein leads to the activation of phospholipase C β3-isoform, therefore increasing cytoplasmic free calcium and stimulating protein kinase C. PST inhibits the cell growth in rat HTC hepatoma cells, mediated by nitric oxide and cyclic GMP production. Elevated levels of PST correlating with catecholamines have been found in gestational diabetes and essential hypertension. Rise in the blood PST level in Type 2 diabetes suggests that PST is a negative regulator of insulin sensitivity and glucose homeostasis.
Security Analysis of HMAC/NMAC by Using Fault Injection
Authors: Jeong Kitae , Lee Yuseop , Sung Jaechul , Hong Seokhie
Published: September 2013

In Choukri and Tunstall (2005), the authors showed that if they decreased the number of rounds in AES by injecting faults, it is possible to recover the secret key. In this paper, we propose fault injection attacks on HMAC/NMAC by applying the main idea of their attack. These attacks are applicable to HMAC/NMAC based on the MD-family hash functions and can recover the secret key with the negligible computational complexity. Particularly, these results on HMAC/NMAC-SHA-2 are the first known key recovery attacks so far.
Neuroprotective Effects of Hesperidin, a Plant Flavanone, on Rotenone-Induced Oxidative Stress and Apoptosis in a Cellular Model for Parkinson’s Disease
Authors: Tamilselvam Kuppusamy , Braidy Nady , Manivasagam Thamilarasan , Essa Musthafa Mohamed , Prasad Nagarajan Rajendra , Karthikeyan Subburayan , Thenmozhi Arokyasamy Justin , Selvaraju Subash , Guillemin Gilles J.
Published: September 2013

Rotenone a widely used pesticide that inhibits mitochondrial complex I has been used to investigate the pathobiology of PD bothin vitroandin vivo. Studies have shown that the neurotoxicity of rotenone may be related to its ability to generate reactive oxygen species (ROS), leading to neuronal apoptosis. The current study was carried out to investigate the neuroprotective effects of hesperidin, a citrus fruit flavanol, against rotenone-induced apoptosis in human neuroblastoma SK-N-SH cells. We assessed cell death, mitochondrial membrane potential, ROS generation, ATP levels, thiobarbituric acid reactive substances, reduced glutathione (GSH) levels, and the activity of catalase, superoxide dismutase (SOD) and glutathione peroxidase (GPx) using well established assays. Apoptosis was determined in normal, rotenone, and hesperidin treated cells, by measuring the protein expression of cytochrome c (cyt c), caspases 3 and 9, Bax, and Bcl-2 using the standard western blotting technique. The apoptosis in rotenone-induced SK-N-SH cells was accompanied by the loss of mitochondrial membrane potential, increased ROS generation, the depletion of GSH, enhanced activities of enzymatic antioxidants, upregulation of Bax, cyt c, and caspases 3 and 9, and downregulation of Bcl-2, which were attenuated in the presence of hesperidin. Our data suggests that hesperidin exerts its neuroprotective effect against rotenone due to its antioxidant, maintenance of mitochondrial function, and antiapoptotic properties in a neuroblastoma cell line.