bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Phase Change Material in Sustainable Cooling of Data Centers
Authors: Dhiman Nikhil , Shah Jeet , Agonafer Dereje , Kannan Naveen , Hoverson James , Kaler Mike 
Published: April 2014

The ever increasing information technology heat load and data center cooling energy are the main reasons to investigate the performance of microencapsulated phase change slurry over other heat transfer fluids.
Microencapsulated phase change slurry is dispersion where the phase change material, microencapsulated by a polymeric capsule, is dispersed in water. Compared to water, these new fluids have a higher heat capacity during phase change and a possible enhancement, as a result of this phase change, in the heat transfer phenomenon. The composition of phase change material used in slurry greatly affects its efficiency, If not selected properly it can cause serious damage, e.g. agglomeration and clogging of pipes.
The main objective of this work is to develop standalone pumpable microencapsulated phase change slurry that is able to withstand shear stresses of the pump and other course surfaces of pipe and pipe joints. In this study, experiments were performed, to determine performance of microencapsulated phase change slurry over conventional heat transfer fluids. After certain pumping cycles, scanning electron microscopy (SEM) has been done to analyze the conditions of shell material of polymeric capsule. Results obtained from SEM show that centrifugal pump is compatible with mPCM particle size upto 3 μm.
It is true that selected mPCS have shown better performance over water in hot water bath in case of thermal storage. Also, closed loop final testing has shown that heat flux is about 2–3 times higher with mPCS than water.
Stochastic Multiscale Modeling and Damage Progression for Composite Materials
Authors: Johnston Joel , Chattopadhyay Aditi 
Published: April 2014

Modeling and characterization of complex composite structures is challenging due to uncertainties inherent in these materials. Uncertainty is present at each length scale in composites and must be quantified in order to accurately model the mechanical response and damage progression of this material. The ability to pass information between length scales permits multiscale models to transport uncertainties from one scale to the next. Limitations in the physics and errors in numerical methods pose additional challenges for composite models. By replacing deterministic inputs with random inputs, stochastic methods can be implemented within these multiscale models making them more robust.
This work focuses on understanding the sensitivity of multiscale models and damage progression variations to stochastic input parameters as well as quantifying these uncertainties within a modeling framework. A multiscale, sectional model is used due to its efficiency and capacity to incorporate stochastic methods with little difficulty. The sectional micromechanics in this model are similar to that of the Generalized Method of Cells with the difference being the discretization techniques of the unit cell and the continuity conditions. A Latin Hypercube sampling technique is used due to its reported computational savings over other methods such as a fully random Monte Carlo simulation. Specifically in the sectional model, the Latin Hypercube sampling method provides an approximate 35 % reduction in computations compared to the fully random Monte Carlo method. The Latin Hypercube sampling is a stratified technique which discretizes the distribution function and randomizes the input parameters within those discretized fields. Within this multiscale modeling framework, a progressive failure theory is implemented using these stochastic methods and a modified Hashin failure theory. With a combined stochastic method and progressive failure theory, this multiscale model is capable of modeling the uncertainty and material property variations for composite materials.
Two Equation Two-Fluid Model Analysis for Stratified Flow Under Kinematic and Dynamic Instabilities
Authors: Lopez de Bertodano Martin A. , Fullmer William D. 
Published: April 2014

The unstable one-dimensional incompressible two-fluid model including a hydrostatic force is reduced to a two equation model in terms of the liquid volume fraction and the liquid velocity. For small density ratios the model may be simplified to a formulation that is equivalent tothe Shallow Water Theory (SWT) equations [Whitham, 1975] with a source term corresponding to the two-fluid model constitutive relations for wall and interfacial shear and to a void gradient term that contains the Kelvin-Helmholtz mechanism.
Linear stability of the SWT equations shows that the model is made well-posed stable by the hydrostatic force. However, unlike the SWT equations, the two equation two-fluid model is only conditionally stable. As the gas velocity increases the model becomes unstable once the kinematic instability occurs, i.e., the Viscous Kelvin-Helmholtz (VKH) instability. When the gas velocity is increased further the model becomes dynamically unstable, i.e., it reaches the Inviscid Kelvin-Helmholtz (IKH) instability limit. Beyond the IKH limit the model becomes ill-posed and requires higher order modelling, e.g. surface tension. Simple analytic expressions for the two instabilities are obtained because of the simplified mathematics of the two equation model. Furthermore, the wave “sheltering” effect, which allows more accurate predictions of the flow regime transition, may be easily incorporated into the analysis. The theory is validated with the new HAWAC flow regime map [Vallee et al., 2010].
The two equation two-fluid model is consistent with all previous results of two-fluid model linear stability for stratified flow and, since it is a special case of SWT, it is amenable to non-linear stability analysis and a very broad body of mathematics literature on non-linear kinematic waves, e.g., Whitham (1974) is now directly applicable when the model is not IKH unstable.
CD4+T Cells: Guardians of the Phagosome
Authors: Tubo Noah J. , Jenkins Marc K. 
Published: April 2014

SUMMARYCD4+T cells are key cells of the adaptive immune system that use T cell antigen receptors to recognize peptides that are generated in endosomes or phagosomes and displayed on the host cell surface bound to major histocompatibility complex molecules. These T cells participate in immune responses that protect hosts from microbes such asMycobacterium tuberculosis,Cryptococcus neoformans,Leishmania major, andSalmonella enterica, which have evolved to live in the phagosomes of macrophages and dendritic cells. Here, we review studies indicating that CD4+T cells control phagosomal infections asymptomatically in most individuals by secreting cytokines that activate the microbicidal activities of infected phagocytes but in a way that inhibits the pathogen but does not eliminate it. Indeed, we make the case that localized, controlled, persistent infection is necessary to maintain large numbers of CD4+effector T cells in a state of activation needed to eradicate systemic and more pathogenic forms of the infection. Finally, we posit that current vaccines for phagosomal infections fail because they do not produce this “periodic reminder” form of CD4+T cell-mediated immune control.
Disease Manifestations and Pathogenic Mechanisms of Group A Streptococcus
Authors: Walker Mark J. , Barnett Timothy C. , McArthur Jason D. , Cole Jason N. , Gillen Christine M. , Henningham Anna , Sriprakash K. S. , Sanderson-Smith Martina L. , Nizet Victor 
Published: April 2014

SUMMARYStreptococcus pyogenes, also known as group AStreptococcus(GAS), causes mild human infections such as pharyngitis and impetigo and serious infections such as necrotizing fasciitis and streptococcal toxic shock syndrome. Furthermore, repeated GAS infections may trigger autoimmune diseases, including acute poststreptococcal glomerulonephritis, acute rheumatic fever, and rheumatic heart disease. Combined, these diseases account for over half a million deaths per year globally. Genomic and molecular analyses have now characterized a large number of GAS virulence determinants, many of which exhibit overlap and redundancy in the processes of adhesion and colonization, innate immune resistance, and the capacity to facilitate tissue barrier degradation and spread within the human host. This improved understanding of the contribution of individual virulence determinants to the disease process has led to the formulation of models of GAS disease progression, which may lead to better treatment and intervention strategies. While GAS remains sensitive to all penicillins and cephalosporins, rising resistance to other antibiotics used in disease treatment is an increasing worldwide concern. Several GAS vaccine formulations that elicit protective immunity in animal models have shown promise in nonhuman primate and early-stage human trials. The development of a safe and efficacious commercial human vaccine for the prophylaxis of GAS disease remains a high priority.
Durable Therapeutic Efficacy Utilizing Combinatorial Blockade against IDO, CTLA-4, and PD-L1 in Mice with Brain Tumors
Authors: Wainwright Derek A. , Chang Alan L. , Dey Mahua , Balyasnikova Irina V. , Kim Chung Kwon , Tobias Alex , Cheng Yu , Kim Julius W. , Qiao Jian , Zhang Lingjiao , Han Yu , Lesniak Maciej S. 
Published: April 2014

Abstract
Purpose: Glioblastoma (GBM) is the most common form of malignant glioma in adults. Although protected by both the blood–brain and blood–tumor barriers, GBMs are actively infiltrated by T cells. Previous work has shown that IDO, CTLA-4, and PD-L1 are dominant molecular participants in the suppression of GBM immunity. This includes IDO-mediated regulatory T-cell (Treg; CD4+CD25+FoxP3+) accumulation, the interaction of T-cell–expressed, CTLA-4, with dendritic cell-expressed, CD80, as well as the interaction of tumor- and/or macrophage-expressed, PD-L1, with T-cell–expressed, PD-1. The individual inhibition of each pathway has been shown to increase survival in the context of experimental GBM. However, the impact of simultaneously targeting all three pathways in brain tumors has been left unanswered.
Experimental Design and Results: In this report, we demonstrate that, when dually challenged, IDO-deficient tumors provide a selectively competitive survival advantage against IDO-competent tumors. Next, we provide novel observations regarding tryptophan catabolic enzyme expression, before showing that the therapeutic inhibition of IDO, CTLA-4, and PD-L1 in a mouse model of well-established glioma maximally decreases tumor-infiltrating Tregs, coincident with a significant increase in T-cell–mediated long-term survival. In fact, 100% of mice bearing intracranial tumors were long-term survivors following triple combination therapy. The expression and/or frequency of T cell expressed CD44, CTLA-4, PD-1, and IFN-γ depended on timing after immunotherapeutic administration.
Conclusions: Collectively, these data provide strong preclinical evidence that combinatorially targeting immunosuppression in malignant glioma is a strategy that has high potential value for future clinical trials in patients with GBM. Clin Cancer Res; 20(20); 5290–301. ©2014 AACR.
Remote Ischemic Postconditioning During Percutaneous Coronary Interventions
Authors: Lavi Shahar , D’Alfonso Sabrina , Diamantouros Pantelis , Camuglia Anthony , Garg Pallav , Teefy Patrick , Jablonsky George , Sridhar Kumar , Lavi Ronit 
Published: April 2014

Background—
Remote ischemic preconditioning may result in reduction in infarct size during percutaneous coronary intervention (PCI). It is unclear whether remote ischemic postconditioning (RIPost) will reduce the incidence of myocardial injury after PCI, and whether ischemic conditioning of a larger remote organ (thigh versus arm) would provide further myocardial protection.

Methods and Results—

We randomized 360 patients presenting with stable or unstable angina (28% of patients) and negative Troponin T at baseline to 3 groups: 2 groups received RIPost (induced by ischemia to upper or lower limb), and a third was the control group. RIPost was applied during PCI immediately after stent deployment, by three 5-minute cycles of blood pressure cuff inflation to >200 mm Hg in the arm or thigh (20 mm Hg in the control) with 5-minute breaks between each cycle. The primary end-point was the proportion of patients with Troponin T levels >3×ULN postprocedure (at 6 or 18–24 hours), where ULN stands for upper limit of normal. A total of 120 patients were randomized to each group. There were no differences in baseline characteristics between the 3 groups. The primary outcome occurred in 30%, 35%, and 35% of the arm, thigh, and control groups, respectively (
P
=0.64). There were no differences in creatine kinase or high sensitivity C-reactive protein levels after PCI or in the incidence of acute kidney injury between the groups.

Conclusions—
RIPost during PCI did not reduce the incidence of periprocedural myocardial injury. Similar effect was obtained when remote ischemia was induced to the upper or lower limb.

Clinical Trial Registration—

URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT00970827.
Stroke After Aortic Valve Surgery
Authors: Messé Steven R. , Acker Michael A. , Kasner Scott E. , Fanning Molly , Giovannetti Tania , Ratcliffe Sarah J. , Bilello Michel , Szeto Wilson Y. , Bavaria Joseph E. , Hargrove W. Clark , Mohler Emile R. , Floyd Thomas F. ,   The Determining Neurologic Outcomes from Valve Operations (DeNOVO) investigators include, Acker Michael A. , Bavaria Joseph E. , Floyd Thomas F. , Giovanetti Tania , Hargrove W. Clark , Kasner Scott E. , Messé Steven R. , Matthai William H. , Mohler Emile R. , Morris Rohinton J. , Pochettino Alberto A. , Price Catherine E. C. , Ratcliffe Sarah J. , Selnes Ola A. , Szeto Wilson Y. , Woo Y. Joseph , Desai Nimesh D. , Augostides John G. , Cheung Albert T. , Hanson C. William , Horak Jiri , Kohl Benjamin A. , Kukafka Jeremy D. , Levy Warren J. , Mickler Thomas A. , Milas Bonnie L. , Savino Joseph S. , Vernick William J. , Weiss Stuart J. 
Published: April 2014

Background—
The incidence and impact of clinical stroke and silent radiographic cerebral infarction complicating open surgical aortic valve replacement (AVR) are poorly characterized.

Methods and Results—

We performed a prospective cohort study of subjects ≥65 years of age who were undergoing AVR for calcific aortic stenosis. Subjects were evaluated by neurologists preoperatively and postoperatively and underwent postoperative magnetic resonance imaging. Over a 4-year period, 196 subjects were enrolled at 2 sites (mean age, 75.8±6.2 years; 36% women; 6% nonwhite). Clinical strokes were detected in 17%, transient ischemic attack in 2%, and in-hospital mortality was 5%. The frequency of stroke in the Society for Thoracic Surgery database in this cohort was 7%. Most strokes were mild; the median National Institutes of Health Stroke Scale was 3 (interquartile range, 1–9). Clinical stroke was associated with increased length of stay (median, 12 versus 10 days;
P
=0.02). Moderate or severe stroke (National Institutes of Health Stroke Scale ≥10) occurred in 8 (4%) and was strongly associated with in-hospital mortality (38% versus 4%;
P
=0.005). Of the 109 stroke-free subjects with postoperative magnetic resonance imaging, silent infarct was identified in 59 (54%). Silent infarct was not associated with in-hospital mortality or increased length of stay.

Conclusions—
Clinical stroke after AVR was more common than reported previously, more than double for this same cohort in the Society for Thoracic Surgery database, and silent cerebral infarctions were detected in more than half of the patients undergoing AVR. Clinical stroke complicating AVR is associated with increased length of stay and mortality.
Global-to-Regional Nested Grid Climate Simulations in the GFDL High Resolution Atmospheric Model
Authors: Harris Lucas M. , Lin Shian-Jiann 
Published: April 2014

A two-way nested grid version of the Geophysical Fluid Dynamics Laboratory High Resolution Atmosphere Model (HiRAM) has been developed that uses simple methods for providing nested grid boundary conditions and mass-conserving nested-to-global communication. Nested grid simulations over the Maritime Continent and over North America were performed, each at two different resolutions: a 110-km mean grid cell width refined by a factor of 3, and a 50-km mean grid cell width refined by a factor of 2. Nested grid simulations were compared against uniform-resolution simulations, and against reanalyses, to determine the effect of grid nesting on both the modeled global climate and the simulation of small-scale features. Orographically forced precipitation was robustly found to be simulated with more detail and greater realism in a nested grid simulation compared with when only the coarse grids were simulated alone. Tropical precipitation biases were reduced in the Maritime Continent region when a nested grid was introduced. Both results were robust to changes in the nested grid parameterization tunings. In North America, cold-season orographic precipitation was improved by nesting, but precipitation biases in the central and eastern United States were little changed. Improving the resolution through nesting also allowed for more intense rainfall events, greater Kelvin wave activity, and stronger tropical cyclones. Nested grid boundary artifacts were more pronounced when a one-way, noninteractive nested grid was used.
AUV Observations of the Diurnal Surface Layer in the North Atlantic Salinity Maximum
Authors: Hodges Benjamin A. , Fratantoni David M. 
Published: April 2014

Abstract
Autonomous underwater vehicle (AUV) surveys of temperature, salinity, and velocity in the upper 10 m of the ocean were carried out in low-wind conditions near the North Atlantic surface salinity maximum as part of the Salinity Processes in the Upper Ocean Regional Study (SPURS) project. Starting from a well-mixed state, the development, deepening, and decay of a warm salty diurnal surface layer was observed at &lt;1-h resolution. The evaporation rate deduced from the freshwater anomaly of the layer corroborates measurements at a nearby flux mooring. Profiles within a few hundred meters of the stationary research vessel showed evidence of mixing, highlighting the effectiveness of AUVs for collecting uncontaminated time series of near-surface thermohaline structure. A two-dimensional horizontal subsurface survey within the diurnal warm layer revealed coherent warm and cool bands, which are interpreted as internal waves on the diurnal thermocline.
Multiplicative and Additive Incremental Variational Data Assimilation for Mixed Lognormal–Gaussian Errors
Authors: Fletcher Steven J. , Jones Andrew S. 
Published: April 2014

Abstract
An advance that made Gaussian-based three- and four-dimensional variational data assimilation (3D- and 4DVAR, respectively) operationally viable for numerical weather prediction was the introduction of the incremental formulation. This reduces the computational costs of the variational methods by searching for a small increment to a background state whose evolution is approximately linear. In this paper, incremental formulations for 3D- and 4DVAR with lognormal and mixed lognormal–Gaussian-distributed background and observation errors are presented. As the lognormal distribution has geometric properties, a geometric version for the tangent linear model (TLM) is proven that enables the linearization of the observational component of the cost functions with respect to a geometric increment. This is combined with the additive TLM for the mixed distribution–based cost function. Results using the mixed incremental scheme with the Lorenz’63 model are presented for different observational error variances, observation set sizes, and assimilation window lengths. It is shown that for sparse accurate observations the scheme has a relative error of ±0.5% for an assimilation window of 100 time steps. This improves to ±0.3% with more frequent observations. The distributions of the analysis errors are presented that appear to approximate a lognormal distribution with a mode at 1, which, given that the background and observational errors are unbiased in Gaussian space, shows that the scheme is approximating a mode and not a median. The mixed approach is also compared against a Gaussian-only incremental scheme where it is shown that as the z-component observational errors become more lognormal, the mixed approach appears to be more accurate than the Gaussian approach.
Ketorolac After Free Tissue Transfer
Authors: Schleiffarth J. Robert , Bayon Rodrigo , Chang Kristi E. , Van Daele Douglas J. , Pagedar Nitin A. 
Published: April 2014

Objective: We sought to compare postoperative pain and complications in patients undergoing free tissue transfer for reconstruction of head and neck defects with and without ketorolac. Methods: In this retrospective cohort study, we identified patients who underwent head and neck free tissue transfer procedures at the University of Iowa between July 2010 and December 2012. A subset of patients received ketorolac as an anti-platelet agent. Main outcome measures include postoperative analgesic use, pain scores, and bleeding complications. Results: We identified 138 free tissue transfers, with 42 procedures in the ketorolac cohort. In the first 7 postoperative days, patients in the ketorolac and non-ketorolac cohorts received equivalent narcotic doses (morphine equivalents, 48.9 mg/day vs 46.6 mg/day, P = .72). The ketorolac group reported higher mean pain scores (3.1 vs 2.4, P = .004). Ketorolac use was not associated with need for transfusion ( P = .86) or number of days with neck drains ( P = .79). Conclusion: Ketorolac did not demonstrate a significant analgesic effect in this group of patients in terms of pain scores and opioid requirements. However, there also was no evidence to suggest a higher likelihood of bleeding complications. Ketorolac may be safely used as an anti-platelet agent, with narcotic requirements unchanged.
A Novel Device for the Clinical Assessment of Intranasal Trigeminal Sensitivity
Authors: Naka Asami , Wolf Axel , Renner Bertold , Mueller Christian A. 
Published: April 2014

Objective: Despite the significance of trigeminal pathology, practical clinical tests that accurately evaluate intranasal trigeminal function are scarce. The aim of the present study is to introduce a practical procedure for the assessment of intranasal trigeminal sensitivity. Methods: We developed a device to stimulate the nasal mucosa using carbon dioxide, which is self-administered intranasally by holding down a timed button until the required sensory response has been triggered. The trigeminal sensitivity is derived from the measured administration time in conjunction with the concentration of carbon dioxide administered. Sixty-three healthy participants were used to validate the device, after which the new device was compared with a standard lateralization task in an additional 16 participants. In 20 participants, the experiment was repeated to verify test–retest reliability. Results: Statistical analysis showed significant consistency in administration-duration in healthy individuals, including those in the test–retest group. Those participants with higher scores in the lateralization task were found to show higher intranasal sensitivity measured by the new device. Conclusion: Herein, we present the design and validation of a novel device for the practical assessment of intranasal trigeminal sensitivity. In this study, we demonstrate the efficacy and reliability of this device.