bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling of tensile modulus of polyolefin-layered silicate nanocomposites: modified micro-mechanical and statistical methods
Authors: Mittal Vikas 
Published: November 2012

Abstract
Applicability and subsequent modification of various composite models for the prediction of the relative tensile modulus of polyolefin nanocomposites has been studied. A number of models, such as the modified Halpin-Tsai, Guth, Mori-Tanaka, Hui and Shia and Takayanagi models, as well as factorial and mixture designs, were considered. Various assumptions in the models, such as uniform shape and size of filler (i.e., complete exfoliation), alignment, as well as interfacial bonding between the components, restrict their application for the prediction of the nanocomposite modulus. The modified Guth model and Halpin-Tsai model, with the ∅m concept, were developed further to incorporate the modulus reduction factors for polyolefin nanocomposites. This allowed the generation of master curves of the modulus reduction factor as a function of the aspect ratio of the filler in the composite. It was observed that the Mori Tanaka model, modified by constructing models of various representative volume elements (RVEs) of the underlying structure of the nanoclay filled polymers, matched the experimental values of the tensile modulus of polyolefin nanocomposites. The modified Hui and Shia model, incorporating the non-bonding interfacial effects, as well as the three component modified Takayanagi model, were also able to predict the tensile modulus of polyolefin nanocomposites efficiently. Factorial and mixture designs did not require the conventionally used assumptions and satisfactorily reflected the material behavior, and were specific to the particular components used to generate nanocomposites. These models were also helpful in predicting the aspect ratio of the filler in the composites, when synergistically combined with other modified models.
Thermal and mechanical characteristics of cement nanocomposites
Authors: Jalal Mostafa , Mansouri Esmaeel 
Published: November 2012

AbstractWidespread applications and advantages of different types of composite materials have drawn researchers’ attention toward the science and technology of composites. Among these materials, cementitious composites have a special place, as they have many applications in various fields of structural and civil engineering. Due to the importance of cementitious composites and their behavior, investigation of their properties is of great importance. Thus in the present study, thermal and mechanical properties of the self-compacting cementitious composites containing different fractions of nano TiO2 have been investigated. Mechanical properties were assessed through compressive, split tensile and flexural tests. The thermal properties were assessed through thermogravimetric analysis (TGA) and conduction calorimetry tests. Accelerated peak appearance in conduction calorimetry tests and more weight loss in thermogravimetric analysis could indicate that TiO2 nanoparticles could lead to strength development at earlier ages and improve the properties of the self-compacting cementitious composites.
Prediction of tensile capacity of adhesive anchors including edge and group effects using neural networks
Authors: Ozturk Murat 
Published: November 2012

AbstractAdhesive anchors are widely used in seismic strengthening applications to add new structural members or sections to existing concrete members due to their high tensile and compressive strengths, low cost, and easy and fast installation. To safely design such anchors, it is very important to know their pullout capacity under axial tensile forces. This paper explores the pullout capacity of both single and groups of adhesive anchors loaded in tension in uncracked concrete. Quadruple anchor groups were considered for group effect. To this end, 142 single anchor tests including edge effect (located near a concrete edge) and 175 quadruple group anchor tests (totally 317 tests) were obtained from literature. The formulated three-layered artificial neural network method (ANN) was trained using 75% of the data set by using different learning algorithms. The methods were tested with the remaining 25%. The variables taken into account in this study are anchor diameter, embedment length, concrete compressive strength, concrete body height, edge distance (for single anchors), and anchor spacing (for group anchors). It was determined that experimental data can be estimated to a notably close extent via the ANN model.
Use of marble dust and fly ash in stabilization of base material
Authors: Zorluer Ismail , Demirbas Abdullah 
Published: November 2012

AbstractMarble dust and fly ash are waste materials and used in various area and industries as an additive material. However, there are still significant amounts of marble dust and fly ash left as waste. Therefore, the reuse of these wastes provides benefits to reduce construction costs and increase sustainability. In this study, a laboratory testing program was conducted on granular soil specimens amended with marble dust and fly ash. The specimens were prepared with granular soil and marble dust-fly ash at different mixing ratios. They were compacted with standard and modified Proctor energies. The specimens were subjected to unconfined compression, California bearing ratio, and freezing-thawing tests. The results of the study show that the strength of a specimen is dependent on the additive ratio, the curing period, compaction energy, and the number of freeze-thaw (F-T) cycles. Generally, unconfined compressive strength (qu) and California bearing ratio (CBR) increased with additive materials, curing times, and high compaction energy. qu decreased and weight loss increased with increasing additives and increasing F-T cycles.
Influence on variation in process parameters for the design of xanthan-gum-facilitated ethyl cellulose microparticles for intestinal specific delivery
Authors: Banerjee Subham , Tiwari Aashish , Yadav Santosh Kumar , Bhattacharya Shiv Sankar , Dagaji Aher Vaibhav , Mondal Pabitra 
Published: November 2012

AbstractXanthan-gum-facilitated aspirin-loaded ethyl cellulose microparticles were prepared by multiple-emulsion solvent evaporation technology and the impact on variation in process parameters was investigated systematically. Scanning electron microscopy was performed to determine the surface morphology of the microparticles before and after dissolution study. X-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) analysis were performed, and yield value, swelling study, encapsulation efficiency, flow properties and dissolution profiles of the prepared formulations were evaluated. The size of microparticles varied between 247 and 410 μm, and 58.34% drug entrapment efficiency was achieved depending on the variation in process parameters. The drug release in acid solutions was slower than in alkaline solution. The microparticles provided extended drug release in alkaline dissolution medium, and the drug release was found to be controlled by Fickian diffusion mechanism. XRD and DSC analyses revealed the amorphous nature of drug in the microparticles. FTIR data indicated the stable character of the encapsulated drug in the microparticles. Thus, variation in process parameters showed a slow and prolonged release of aspirin in simulated intestinal fluid.
CaV1.3-Driven SK Channel Activation Regulates Pacemaking and Spike Frequency Adaptation in Mouse Chromaffin Cells
Authors: Vandael David H. F. , Zuccotti Annalisa , Striessnig Joerg , Carbone Emilio 
Published: November 2012

Mouse chromaffin cells (MCCs) fire spontaneous action potentials (APs) at rest. Cav1.3 L-type calcium channels sustain the pacemaker current, and their loss results in depolarized resting potentials (Vrest), spike broadening, and remarkable switches into depolarization block after BayK 8644 application. A functional coupling between Cav1.3 and BK channels has been reported but cannot fully account for the aforementioned observations.Here, using Cav1.3−/−mice, we investigated the role of Cav1.3 on SK channel activation and how this functional coupling affects the firing patterns induced by sustained current injections. MCCs express SK1–3 channels whose tonic currents are responsible for the slow irregular firing observed at rest. Percentage of frequency increase induced by apamin was found inversely correlated to basal firing frequency. Upon stimulation, MCCs build-up Cav1.3-dependent SK currents during the interspike intervals that lead to a notable degree of spike frequency adaptation (SFA). The major contribution of Cav1.3 to the subthreshold Ca2+charge during an AP-train rather than a specific molecular coupling to SK channels accounts for the reduced SFA of Cav1.3−/−MCCs. Low adaptation ratios due to reduced SK activation associated with Cav1.3 deficiency prevent the efficient recovery of NaVchannels from inactivation. This promotes a rapid decline of AP amplitudes and facilitates early onset of depolarization block following prolonged stimulation. Thus, besides serving as pacemaker, Cav1.3 slows down MCC firing by activating SK channels that maintain NaVchannel availability high enough to preserve stable AP waveforms, even upon high-frequency stimulation of chromaffin cells during stress responses.
Demographic Inference Reveals African and European Admixture in the North AmericanDrosophila melanogasterPopulation
Authors: Duchen Pablo , Živković Daniel , Hutter Stephan , Stephan Wolfgang , Laurent Stefan 
Published: November 2012

AbstractDrosophila melanogaster spread from sub-Saharan Africa to the rest of the world colonizing new environments. Here, we modeled the joint demography of African (Zimbabwe), European (The Netherlands), and North American (North Carolina) populations using an approximate Bayesian computation (ABC) approach. By testing different models (including scenarios with continuous migration), we found that admixture between Africa and Europe most likely generated the North American population, with an estimated proportion of African ancestry of 15%. We also revisited the demography of the ancestral population (Africa) and found—in contrast to previous work—that a bottleneck fits the history of the population of Zimbabwe better than expansion. Finally, we compared the site-frequency spectrum of the ancestral population to analytical predictions under the estimated bottleneck model.
Genetic Dissection of Peroxisome-Associated Matrix Protein Degradation in Arabidopsis thaliana
Authors: Burkhart Sarah E , Lingard Matthew J , Bartel Bonnie 
Published: November 2012

Abstract
Peroxisomes are organelles that sequester certain metabolic pathways; many of these pathways generate H2O2, which can damage proteins. However, little is known about how damaged or obsolete peroxisomal proteins are degraded. We exploit developmentally timed peroxisomal content remodeling in Arabidopsis thaliana to elucidate peroxisome-associated protein degradation. Isocitrate lyase (ICL) is a peroxisomal glyoxylate cycle enzyme necessary for early seedling development. A few days after germination, photosynthesis begins and ICL is degraded. We previously found that ICL is stabilized when a peroxisome-associated ubiquitin-conjugating enzyme and its membrane anchor are both mutated, suggesting that matrix proteins might exit the peroxisome for ubiquitin-dependent cytosolic degradation. To identify additional components needed for peroxisome-associated matrix protein degradation, we mutagenized a line expressing GFP–ICL, which is degraded similarly to endogenous ICL, and identified persistent GFP-ICLfluorescence (pfl) mutants. We found three pfl mutants that were defective in PEROXIN14 (PEX14/At5g62810), which encodes a peroxisomal membrane protein that assists in importing proteins into the peroxisome matrix, indicating that proteins must enter the peroxisome for efficient degradation. One pfl mutant was missing the peroxisomal 3-ketoacyl-CoA thiolase encoded by the PEROXISOME DEFECTIVE1 (PED1/At2g33150) gene, suggesting that peroxisomal metabolism influences the rate of matrix protein degradation. Finally, one pfl mutant that displayed normal matrix protein import carried a novel lesion in PEROXIN6 (PEX6/At1g03000), which encodes a peroxisome-tethered ATPase that is involved in recycling matrix protein receptors back to the cytosol. The isolation of pex6-2 as a pfl mutant supports the hypothesis that matrix proteins can exit the peroxisome for cytosolic degradation.
toca-1 Is in a Novel Pathway That Functions in Parallel with a SUN-KASH Nuclear Envelope Bridge to Move Nuclei in Caenorhabditis elegans
Authors: Chang Yu-Tai , Dranow Daniel , Kuhn Jonathan , Meyerzon Marina , Ngo Minh , Ratner Dmitry , Warltier Karin , Starr Daniel A 
Published: November 2012

Abstract
Moving the nucleus to an intracellular location is critical to many fundamental cell and developmental processes, including cell migration, differentiation, fertilization, and establishment of cellular polarity. Bridges of SUN and KASH proteins span the nuclear envelope and mediate many nuclear positioning events, but other pathways function independently through poorly characterized mechanisms. To identify and characterize novel mechanisms of nuclear migration, we conducted a nonbiased forward genetic screen for mutations that enhanced the nuclear migration defect of unc-84, which encodes a SUN protein. In Caenorhabditis elegans larvae, failure of hypodermal P-cell nuclear migration results in uncoordinated and egg-laying–defective animals. The process of P-cell nuclear migration in unc-84 null animals is temperature sensitive; at 25° migration fails in unc-84 mutants, but at 15° the migration occurs normally. We hypothesized that an additional pathway functions in parallel to the unc-84 pathway to move P-cell nuclei at 15°. In support of our hypothesis, forward genetic screens isolated eight emu (enhancer of the nuclearmigration defect ofunc-84) mutations that disrupt nuclear migration only in a null unc-84 background. The yc20 mutant was determined to carry a mutation in the toca-1 gene. TOCA-1 functions to move P-cell nuclei in a cell-autonomous manner. TOCA-1 is conserved in humans, where it functions to nucleate and organize actin during endocytosis. Therefore, we have uncovered a player in a previously unknown, likely actin-dependent, pathway that functions to move nuclei in parallel to SUN-KASH bridges. The other emu mutations potentially represent other components of this novel pathway.
Circadian Rhythm Sleep Disorders
Authors: Saiprakash B. Venkateshiah  
Published: November 2012

Suprachiasmatic nucleus is the master circadian clock that regulates various endogenous circadian rhythms. Light and social cues are important factors that help align the endogenous circadian rhythms to the 24 hour day. Circadian rhythm sleep disorders can be due to abnormalities in the endogenous circadian clock (“intrinsic disorders”) such as delayed sleep phase type, advanced sleep phase type, free running type, and irregular sleep wake rhythm type. Shift work or air travel leads to an artificial mismatch between the endogenous circadian clock and the external environment (“extrinsic disorders”) leading to shift work disorder and jet lag disorder. Individuals with circadian rhythm sleep disorders are presented with insomnia or excessive sleepiness or both.These disorders are under recognized in the general population but they can affect a significant number of people if a the large number of shift workers and air travelers are considered. The symptoms may be misdiagnosed for other common sleep disorders such as sleep apnea or insomnia. Meticulous history and sleep diary data are integral tools in diagnosing CRSD. Actigraphs (activity monitors) may supplement the sleep diary data. In the past two decades major advances have been made in understanding the genetic basis of these disorders. Understanding the circadian principles has led to various therapeutic options such as phototherapy and exogenous melatonin.
A Balancing Act? The Implications of Mixed Strategies for Performance Measurement System Design
Authors: Dekker Henri C. , Groot Tom , Schoute Martijn 
Published: November 2012

ABSTRACT
This paper examines how firms design performance measurement systems (PMSs) to support the pursuit of mixed strategies. In particular, we examine the implications of firms' joint strategic emphasis on both low cost and differentiation for their use of performance measurement and incentive compensation. Analysis of survey data of 387 firms shows that more than half of the sample to some extent or fully mixes strategic priorities, while strategic priorities resembling strategic archetypes (primarily low cost or differentiation) populate only 36 percent of the sample. Our analyses support that, as compared to archetypal strategies, pursuing mixed strategies elicits design of more comprehensive and complex PMSs that are aimed at balancing effort and decisions toward the multiple strategies pursued.
Decreased Reactivity of Skin Microcirculation in Response to l-Arginine in Later-Onset Type 1 Diabetes
Authors: Neubauer-Geryk Jolanta , Kozera Grzegorz M. , Wolnik Bogumil , Szczyrba Sebastian , Nyka Walenty M. , Bieniaszewski Leszek 
Published: November 2012

OBJECTIVE
The aim of our study was to evaluate the vasodilatory effect of l-arginine infusion on the skin microcirculation and to assess the relationship between this effect and the presence of microangiopathy in patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS
Capillaroscopy was performed before and after l-arginine infusion in 48 diabetic patients (26 women and 22 men; age, 39.8 ± 6.3 years) and 24 volunteers free of any chronic disease (13 women and 11 men; age, 38.0 ± 6.7 years). The skin microcirculation reactivity, as expressed by the percentage of area covered by capillaries (coverage) and the distance between capillaries (distance), and the relationship between microcirculation reactivity and the presence of microangiopathic complications were assessed.

RESULTS
The distance before l-arginine infusion was significantly lower in patients than in controls (221 [153–311] vs. 240 [185–356] µm; P = 0.02) and did not differ after l-arginine infusion (223.5 [127–318] vs. 242.5 [181–341] µm; P = 0.27). The difference between the coverage values obtained before and after l-arginine infusion (Δcoverage) was significantly different from zero in the control group but not in the diabetes group. Patients with later onset of diabetes were characterized by decreased skin microcirculation reactivity when compared with patients with earlier onset of diabetes (−1.18 [−5.07 to 11.60] vs. 1.36 [−6.00 to 8.06]; P = 0.02) despite the higher prevalence of retinopathy in patients with earlier onset of diabetes (64% vs. 26%; P = 0.02).

CONCLUSIONS
Skin microvascular reactivity is impaired in patients with later onset of type 1 diabetes. Capillaroscopy with l-arginine infusion is useful for the identification of skin microangiopathy in type 1 diabetes.
Population-Based Cohort Analyses of the Bidirectional Relationship Between Type 2 Diabetes and Depression
Authors: Chen Pei-Chun , Chan Yen-Ting , Chen Hua-Fen , Ko Ming-Chung , Li Chung-Yi 
Published: November 2012

OBJECTIVE
This study addresses the strength of association for the bidirectional relationship between type 2 diabetes and depression.

RESEARCH DESIGN AND METHODS
We used two cohort studies with the same source of database to determine the link between depression and type 2 diabetes. The data analyzed included a random sample of 1 million beneficiaries selected from the National Health Insurance claims in 2000. The analysis of diabetes predicting the depression onset consisted of 16,957 diabetic patients and the same number of sex- and age-matched nondiabetic control subjects. The analysis of depression predicting diabetes onset included 5,847 depressive patients and 5,847 sex- and age-matched nondepressive control subjects. The follow-up period was between 2000 and 2006, and onset of end points was identified from ambulatory care claims. The Cox proportional hazards regression model adjusted for potential confounders was used to estimate relative hazards.

RESULTS
The first cohort analysis noted an incidence density (ID) of 7.03 per 1,000 person-years (PY) and 5.04 per 1,000 PY for depression in diabetic and nondiabetic subjects, respectively, representing a covariate-adjusted hazard ratio (HR) of 1.43 (95% CI 1.16–1.77). The second cohort analysis noted an ID of 27.59 per 1,000 PY and 9.22 per 1,000 PY for diabetes in depressive and nondepressive subjects, respectively. The covariate-adjusted HR was stronger at 2.02 (1.80–2.27) for incident diabetes associated with baseline depression.

CONCLUSIONS
The two cohort studies provided evidence for the bidirectional relationship between diabetes and depression, with a stronger association noted for the depression predicting onset of diabetes.
Generic Medications and Blood Pressure Control in Diabetic Hypertensive Subjects
Authors: Cummings Doyle M. , Letter Abraham J. , Howard George , Howard Virginia J. , Safford Monika M. , Prince Valerie , Muntner Paul 
Published: November 2012

OBJECTIVE
To investigate temporal improvements in blood pressure (BP) control in subjects with diabetes and policy changes regarding generic antihypertensives.

RESEARCH DESIGN AND METHODS
In a cross-sectional study we used logistic regression models to investigate the temporal relationship between access to generic antihypertensive medications and BP control (&lt;130/80 mmHg) in 5,375 subjects (mean age, 66 ± 9 years; 61% African American) with diabetes and hypertension (HTN) enrolled in the national Results from the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort study between 2003 and 2007. At enrollment, BP was measured and medications in the home determined by medication label review by a trained professional. Generic antihypertensive medication status was ascertained from the U.S. Food and Drug Administration.

RESULTS
The percentage of subjects accessing generically available antihypertensive medications increased significantly from 66% in 2003 to 81% in 2007 (P &lt; 0.0001), and the odds of achieving a BP &lt;130/80 mmHg in 2007 was 66% higher (odds ratio 1.66 [95% CI 1.30–2.10]) than in 2003. Nevertheless, &lt;50% of participants achieved this goal. African American race, male sex, limited income, and medication nonadherence were significant predictors of inadequate BP control. There was no significant relationship between access to generic antihypertensives and BP control when other demographic factors were included in the model (0.98 [0.96–1.00]).

CONCLUSIONS
Among African American and white subjects with HTN and diabetes, BP control remained inadequate relative to published guidelines, and racial disparities persisted. Although access to generic antihypertensives increased, this was not independently associated with improved BP control, suggesting that poor BP control is multifactorial.