bluuebunny/crossref_metadata_2025 huggingface dataset:
P-h Curves and Hardness Value Prediction for Spherical Indentation Based on the Representative Stress Approach
Authors: Budiarsa I. Nyoman , Jamal Mikdam
Published: January 2014

In this work, finite element (FE) model of spherical indentation has been developed and validated. The relationships between constitutive materials parameters (σy and n) of elastic-plastic materials, indentation P-h curves and hardness on spherical indenters has been systematically investigated by combining representative stress analysis and FE modelling using steel as a typical model material group. Parametric FE models of spherical indentation have been developed. Two new approaches to characterise the P-h curves of spherical indentation have been developed and evaluated. Both approaches were proven to be adequate and effective in predicting indentation P-h curves. The concept and methodology developed is to be used to predict Rockwell hardness value of materials through direct analysis and validated with experimental data on selected sample of steels. The Hardness predicted are compared with the experimental data and showed a good agreement. The approaches established was successfully used to produce hardness values of a wide range of material properties, which is then used to establish the relationship between the hardness values with representative stress.
Effects of Heat Treatment and Titanium Nitride (TiN) Coating Deposited by Sputtering Technique PVD on Duylos 2510 Tool Steel Substrate
Authors: Malau Viktor , Subagyo Subagyo , Supriyanto Supriyanto
Published: January 2014

The objective of this research is to characterize the effects of heat treatment such as quenching, tempering and TiN coating on mechanical and physical properties of duylos 2510 steel. These mechanical properties include wear rate, hardness, impact toughness, whereas physical properties are microstructures. Duylos 2510 steel is a cold work tool steel and has chemical composition (wt %) of 1C; 0,6 Cr; 0,1 V; 1 Mn; 0,25 Si and 0,6 W.Quenching process has been conducted by heating the specimens on austenite temperature of 800 °C with the soaking time of 30 minutes and then cooling these specimens in oil medium. Tempering process was done at temperatures of 100, 200, 300, 400, 500 dan 600 °C with holding time of 2 hours.TiN coating has been deposited on substrates by sputtering technique of Physical Vapor Deposition at temperatures of 100, 150, 200 and 250 °C with sputtering time of 45 minutes. The mechanical and physical properties have been characterized by wear test, Vickers micro hardness test, Charpy impact test, and metallography test. This research was performed at room temperature and the major parameters of this research were tempering and sputtering temperatures.The results show that tempering temperature variations give significant modification of mechanical properties. In general, the Vickers micro-hardness decreases if tempering temperatures of the specimen increase. The highest Vickers micro-hardness of TiN coatings is 290 HV0,01 for the specimen having sputtering temperature of 200 °C. Wear rate and impact energy increase if tempering temperatures increase. The results also show that the Vickers micro-hardness of coated specimens is higher than the micro Vickers hardness of non-coated specimens
Effect of Electron Beam Irradiation on Mechanical and Thermal Properties of Ethylene Vinyl Acetate/Polyamide 6/High Density Polyethylene Nanocomposite
Authors: Hamid Farizah , Akhbar Suffiyana , Ku Hamid Ku Halim , Faizal Abdul Rahman Mohd
Published: January 2014

The effect of electron beam irradiation on mechanical properties of Ethylene vinyl acetate (EVA) with polyamide 6/high density polyethylene/HDPE-g-MAH and montmorillonite (MMT) were prepared by melt blending the characterization were investigated. The composites were characterized by Fourier Transform Infrared (FTIR) spectrophotometer and Thermogravimetric Analyzer (TGA) The samples were cross-linked by electron beam and irradiated at the dosage range of 0-200 kGy and 3.0 MeV. The mechanical properties of the samples which are tensile test and flexural test were measured by universal tensile machine whiles hardness was measured using Rockwell hardness tester. The gel content was performed to determine the formation of crosslinking and it showed improvement with increase dose up to 150 kGy. The result shows the increasing of tensile strength, tensile modulus, and hardness at the dosage 150 kGy but slightly decline at dose up to 200 kGy. Meanwhile TGA test showed that both irradiated and unirradiated samples have same trend characterization but irradiated samples are slightly more thermal stability. As a conclusion the electron beam irradiation enhance mechanical and thermal properties of ethylene vinyl acetate/polyamide 6/high density polyethylene nanocomposite.
Effect of Intercritical Annealing Temperature and Holding Time on Microstructure and Mechanical Properties of Dual Phase Low Carbon Steel
Authors: Alfirano Alfirano , Samdan Wibawa , Maulud Hidayat
Published: January 2014

Dual phase steels are an important advanced high strength steel, which have been widely used in the automotive industry for vehicle components requiring light weight and safety. In this study, the formation of dual phase structure with various volume fraction of martensite in a low carbon steel SS400 during intercritical annealing were investigated. It was found that intercritical annealing temperature and holding time affected the microstructure and mechanical properties of dual phase low carbon steel. The specimens were heated at intercritical annealing temperature of 750°C, 775°C, 800°C and 825°C, for holding periods of 6-18 minutes, followed by water quenching in order to get a dual phase ferrite and martensite. After quenching, it was obtained the optimal annealing conditions at 800°C with a holding periods of 10 minutes. In this condition, the tensile strength was increased up to 621 N/mm2 or 39.24% higher than the initial condition, while the elongation decreased up to 13.8%. The hardness of specimens increased from 127.7 to 235.83 HVN or up to 84.67% higher than the initial condition. Meanwhile the volume fraction of martensite was 24.08%. The higher the temperature of the heating value of grain growth rate constant (K) increases. In addition, at the optimal poin, the value of K (grain growth rate constant) and n (Avramis exponent) were 0.263 and 0.318, respectively, with activation energy (Q) of 3.98 J/mol.
The Influence of High Content of Silicon in Austenitic Stainless Steel to Corrosion Rate in Sulphuric Acid
Authors: Gapsari Femiana , Wahyudi Slamet , Sumawan Sumawan
Published: January 2014

This study is aimed at investigating the performance of saramet compared to other austenitic stainless steel (SS) types. Saramet is a type of austenitic SS which contains Silicon (Si) higher than others. The research treatment was divided into 2 activities which were at room temperature and high temperature. The material used were saramet, SS 304 and SS 316L. Corrosion test was conducted by using weight losing method and electrochemical. The findings show that saramet is more resistant to corrosion compared to SS 304 and SS 316L both at high and room temperature. Saramet has better performance at high temperature.
Slump Flow Modeling of Self-Compacting Concrete Using Smooth Support Vector Regression (SSVR)
Authors: Hadiwidodo Yoyok Setyo , Purnami Santi Wulan
Published: January 2014

A new method of prediction based on smooth support vector regression (SSVR) is introduced to resolve the slump flow modelling of self-compacting concrete (SCC). The slump flow is a function of the content of all concrete ingredients, including cement, silica fume, water, superplasticizer, coarse and fine aggregate. In this paper, the basic ideas underlying SSVR are reviewed, and the potential of the SSVR for multiple regression (modelling) problems is demonstrated by applying the method to model of slump flow from experimental data. The results of experimentation indicate that SSVR has excellent performance on slump flow prediction. Compared with traditional prediction method such as second order regression, SSVR has much more accurate and effective to prediction of slump flow and it is very promising result.
Effect of Starter Defect to GIIC of Unidirectional CFRP Composite
Authors: Nor Fethma M. , Lee H.Y. , Lim J.Y. , Tamin M.N. , Kurniawan Denni
Published: January 2014

Critical strain energy release rate in CFRP composites characterizes the delamination resistance. More study is still needed to measure the critical strain energy release rate in sliding shear mode (GIIC) considering various factors that influence its measurement. This study evaluates one of the influencing factors, the starter defect. Two types of on thin, unidirectional CFRP composites with one having thin film insert as starter defect and another one with pre-crack under Mode II loading were prepared and tested in three point bending end notch flexure (3ENF) test. It was found that the (GIIC) of the former was more than twice higher than that of the latter, supposedly due to the presence of resin rich region in the former.
Computational Fluid Dynamic Using Parallel Loop of Multi-Cores Processor
Authors: Siow C.L , Jaswar Jaswar , Afrizal Efi
Published: January 2014

Computational Fluid Dynamics (CFD) software is often used to study fluid flow and structures motion in fluids. The CFD normally requires large size of arrays and computer memory and then caused long execution time. However, Innovation of computer hardware such as multi-cores processor provides an alternative solution to improve this programming performance. This paper discussed loop parallelize multi-cores processor for optimization of sequential looping CFD code. This loop parallelize CFD was achieved by applying multi-tasking or multi-threading code into the original CFD code which was developed by one of the authors. The CFD code was developed based on Reynolds Average Navier-Stokes (RANS) method. The new CFD code program was developed using Microsoft Visual Basic (VB) programming language. In the early stage, the whole CFD code was constructed in a sequential flow before it is modified to parallel flow by using VBs multi-threading library. In the comparison, fluid flow around the hull of round-shaped FPSO was selected to compare the performance of both the programming codes. Besides, executed results of this self-developed code such as pressure distribution around the hull were also presented in this paper.
Empirical Correlations for Sizing Adiabatic Capillary Tube Using LPG as Refrigerant in Split-Type Air-Conditioner
Authors: Sulaimon Shodiya , Aziz Azhar Abdul , Darus Amer Nordin , Nasution Henry
Published: January 2014

This paper presents correlations for sizing adiabatic capillary tubes which serves as an expansion device in split-type air-conditioner with LPG, novel hydrocarbon (HC) mixtures of butane (HC600) and propane (HC290) as refrigerant. A homogenous two-phase flow model developed by the authors and also experimental investigation of the Liquified Petroluem Gas (LPG) refrigerant flow in adiabatic capillary tubes were used in this study. The theoretical model was used to assess various percentage compositions of these HC mixtures and validated with the experimental data. For each HC refrigerant mixture, correlations for sizing adiabatic capillary tube which contains the relevant factors, viz. capillary tube inner diameter, inlet pressure, refrigerant mass flow rate, capillary tube surface roughness and capillary tube inlet subcooling was developed. The proposed correlations were compared with the authors measured data and found to be in good agreement. Further validation was made by comparing the mass flow rates predictions of the correlations with experimental data of previous studies and found that these correlations are consistent. The correlations can be used in small vapour compression refrigeration systems working with the HC refrigerant mixtures for practical design and optimization.
Laser Cold Ablation as a Cutting Edge Method of Forming Silicon Wafers Used in Solar Cells
Authors: Sęk Piotr , Tofil Szymon
Published: January 2014

The article shows experimental results of mild cutting of surface layers of polycrystalline silicon photovoltaic cells with a picoseconds UV laser. Current technology makes a strong point on reliability and quality of photovoltaic microprocessing. Using short impulse lasers guarantee best quality of cutting edge without burr, HAZ and changing crystalline structure of the base material, with is very important due to electrical conductivity of the solar cell.
Factorial Approach to Assessment of GPU Computational Efficiency in Surrogate Models
Authors: Pietraszek Jacek , Szczotok Agnieszka , Kocyłowska Elżbieta
Published: January 2014

Surrogate models are very useful to replace very accurate but time-consuming huge data numerical models. The process of construction and optimization of surrogate models may require large computational power. It may be delivered by multi-core CPU or by massively multi-core GPGPU. This paper presents a consistent approach to make quantitative assessment of the computational efficiency with different hardware configurations: with one and multi-core CPU and with GPGPU card. The design of experiments factorial approach is used to analysis of the obtained data. The linear main effects model with two-way interaction is identified. The results show that the investment to multi-core CPU and GPGPU cards simultaneously is impractical due to negligible effects of CPU efficiency which is masked by dominated GPGPU performance.
Tribological Properties of Diamond-Like Carbon Coatings
Authors: Madej Monika
Published: January 2014

The aim of the study was to analyze the superhard anti-wear diamond-like carbon coatings produced by Plasma Assisted Chemical Vapor Deposition (PACVD) and Physical Vapour Deposition (PVD). The a-C:H and a-C:H:W coatings were deposited on steel elements operating under friction conditions. The analysis involved comparing the tribological properties of coated metal elements with those of uncoated elements. It was essential to analyze how the coating composition and structure influence the tribological behaviour of elements under dry and lubrication friction conditions. The coating structure was analyzed by observing the topography of the surface and the cross-sections using an atomic force microscope (AFM) and a scanning electron microscope (SEM). The results were employed to determine the elemental composition and thickness of the coatings. The tribological tests were performed applying a ball-on-disc tribometer and using a pin-on-plate tribometer. The tribological properties were analyzed also in a micro scale using a microtribometer. Compared with the substrate material - steel, the diamond-like carbon coatings showed lower linear wear, lower friction coefficient and higher hardness.
Improving Fatigue Life of Riveted Joints by Rivet Hole Sizing
Authors: Lipski Adam , Lis Zbigniew
Published: January 2014

The aim of this paper is to assess the impact of the rivet hole sizing process on the fatigue life based on the example of the structural connections characteristic for riveted joints used in aviation industry. Test specimens reflected the structural connection consisting in a riveted lap joint of an airplane plating stiffened with a T-bar. Connected plates and the T-bar are made of D16CzATW aluminum alloy. 3 mm diameter oval head solid rivets for aviation-related purposes were made of PA24 aluminum. During fatigue tests, individual specimens with non-sized holes and with sized holes were subjected to uniaxial, one-sided, fixed-amplitude loading (R = 0). It can be concluded from the fatigue life comparison that introduction of an additional operation in the riveting process, i.e. the hole sizing, results in significant, about two-fold increase of the fatigue life of the riveted structural connection, even at slight sizing degree. The difference of the specimen damage nature was observed between specimens with sized and non-sized holes.
Study on Fatigue Cracks in Steel – Concrete Shear Connectors Composite Dowels MCL
Authors: Rowiński Sławomir , Lorenc Wojciech , Kożuch Maciej
Published: January 2014

In recent years many experimental researches were carried out on steel-concrete composite beams with shear connectors of composite-dowels type. Shear connection is mainly used in bridge construction, where strength and fatigue durability of structure are important issues. Research on fatigue in the Preco-Beam project [1] have confirmed the hypothesis that the initiating and propagating crack in steel connecting beam may lead to the loss of its continuity, resulting in failure or even destruction of superstructure [2,. However, it should be noted that these studies were carried out for a specific type of mechanical connector, called PZ-type (Fig. 1). Within next years different shape was developed (MCL shape), which combines many advantages and eliminates disadvantages of the previous types of shapes [4]. In the study [5] complex fatigue tests of beams (in scale similar to natural) were conducted at the Wrocław University of Technology. The objective of that study was to describe the behavior of MCL-type steel connectors. Two failure mechanisms of steel connectors were presented: so-called tearing of steel flange and pulling out of steel dowel. This paper presents the course and the results of macroscopic and microscopic tests of observed fatigue cracks. For the selected crack a profilogram was prepared, which allowed explaining causes of its initiation and characteristics of its development.
Monosaccharidic Push-pull Butadienes: Versatile Synthetic Intermediates
Authors: Bari Ahmed
Published: January 2014

Monosaccharidic push-pull butadienes are interesting building blocks for the synthesis of various heterocyclic and natural products due to their biological prevalence and significant p-electron interactions between donor and acceptor groups. A series of 1,5-anhydro-3,4,6-tri-O-benzyl-2-deoxy- 2-formyl-D-arabino-hex-1-enitol (2) and 1,5-anhydro-3,4-di-O-benzyl-2-deoxy-2-formyl-L-erythrohex- 1-enitol (4) derived push-pull branched chain sugars have been synthesized by condensation with active methylene compounds using basic aluminum oxide (Al2O3) or anhydrous sodium acetate (NaOAc) at room temperature. The compounds have been fully characterized by spectroscopic techniques and elemental analyses.
Ab-initio Studies of the Electronic Structures of the Hexavalent Uranium Compounds K2UO4 and Na4UO5
Authors: Matar Samir F.
Published: January 2014

Band theoretical results within the density functional theory are reported for the uranates K2UO4 and Na4UO5. The two structures are differentiated respectively by uranyl and reverse uranyl-type short U-O distances characterizing the UO6 octahedra, as also reflected by larger compressibility and stability of the potassium-based uranate derived from energy-volume equations of states and the cohesive energy. A larger ionic character of Na4UO5 is inferred from comparative Bader charge analyses. The two uranates are insulators with a larger band gap and less extended valence and conduction bands for Na4UO5. Chemical bonding shows major interactions for U-O versus Na,K-O and is further differentiated as a function of the distances. The band structure results confirm the hexavalent character of the uranium atoms.
Intercalibration of GOES 8–15 solar proton detectors
Authors: Rodriguez J. V. , Krosschell J. C. , Green J. C.
Published: January 2014

This work provides a relative intercalibration of the high‐energy proton channels from the Energetic Particle Sensors (EPS) flown on the Geostationary Operational Environmental Satellites (GOES) since 1994 using a technique that depends on features that arise during high solar wind dynamic pressure. Based on observations of solar energetic protons from polar‐orbiting and geostationary satellites (1998–2013), solar proton fluxes are isotropic at geostationary orbit during periods of high solar wind dynamic pressure (Pdyn>5−10 nPa). The observed isotropy results from the solar proton fluxes having rigidities (momenta per unit charge) greater than their geomagnetic cutoffs over the complete energy and angular responses of the satellite‐borne detector. (The cutoff in a given direction is the rigidity below which an interplanetary particle cannot reach that location.) Under these conditions, we determine the relative responses of the EPS flown on GOES 8 through 15. These detectors are widely used for alerts of the radiation hazard posed to spacecraft and humans by solar energetic particle events; therefore, it is important to know their relative responses. The results of this low‐scatter intercalibration analysis show that the relative responses agree to 20% or better (sometimes better than 1%). The effect of such relative calibration differences on the derived integral fluxes used by NOAA for its real‐time solar radiation storm alerts is shown to be small (<10%). This method can be used to intercalibrate solar proton detectors of different design if their broad energy response functions are carefully accounted for.
Facile preparation of superhydrophobic polyester surfaces with fluoropolymer/SiO2 nanocomposites based on vinyl nanosilica hydrosols
Authors: Xu Lihui , Cai Zaisheng , Shen Yong , Wang Liming , Ding Ying
Published: January 2014

A facile method to prepare superhydrophobic fluoropolymer/SiO2 nanocomposites coating on polyester (PET) fabrics was presented. The vinyl nanosilica (VSiO2) hydrosols were prepared via one‐step water‐based sol‐gel reaction with vinyl trimethoxy silane as the precursors in the presence of the base catalyst and composite surfactant. Based on the VSiO2 hydrosol, a fluorinated acrylic polymer/silica (FAP/SiO2) nanocomposite was prepared by emulsion polymerization. The FAP/SiO2 nanocomposites were coated onto the polyester fabrics by one‐step process to achieve superhydrophobic surfaces. The results showed that silica nanoparticles were successfully incorporated into the FAP/SiO2 nanocomposites, and a specific surface topography and a low surface free energy were simultaneously introduced onto PET fibers. The prepared PET fabric showed excellent superhydrophobicity with a water contact angle of 151.5° for a 5 μL water droplet and a water shedding angle of 12° for a 15 μL. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40340.
Ageing and Community: Introduction to the Special Issue
Authors: Provencher Claudine , Keating Norah , Warburton Jeni , Roos Vera
Published: January 2014

Population ageing is one of the major contemporary issues facing societies across the world. Originally framed as a major social and economic challenge, demographic ageing is now beginning to be seen as offering huge potential to individuals as well as to their communities. It is this positive potential that we explore in this issue by utilising two key disciplinary approaches—social gerontology and social/community psychology. In this introduction, we argue that focus on only one or the other of these perspectives is limiting. Instead, a more critical approach is needed that incorporates the strengths of both disciplines in order to build a more complete and stronger understanding of ageing and community. Thus, a focus on social gerontology highlights ageing issues and explores the diversity of older people and their interactions with community. By incorporating a social/community psychology approach, there is potential to complement this body of work through a deeper level of analysis around community, as well as individual and relational dimensions. The result is a special issue that brings together these two perspectives to address some of the shortcomings of approaching ageing through solely one disciplinary lens. Copyright © 2013 John Wiley & Sons, Ltd.
Validation and incremental value of the hybrid algorithm for CTO PCI
Authors: Pershad Ashish , Eddin Moneer , Girotra Sudhakar , Cotugno Richard , Daniels David , Lombardi William
Published: January 2014

Objectives

To evaluate the outcomes and benefits of using the hybrid algorithm for chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

Background

The hybrid algorithm harmonizes antegrade and retrograde techniques for performing CTO PCI. It has the potential to increase success rates and improve efficiency for CTO PCI. No previous data have analyzed the impact of this algorithm on CTO PCI success rates and procedural efficiency.

Methods

Retrospective analysis of contemporary CTO PCI performed at two high‐volume centers with adoption of the hybrid technique was compared to previously published CTO outcomes in a well matched group of patients and lesion subsets.

Results

After adoption of the hybrid algorithm, technical success was significantly higher in the post hybrid algorithm group 189/198 (95.4%) vs the pre‐algorithm group 367/462 (79.4%) (P < 0.001). Procedural success in the post hybrid algorithm group 175/198 (88.3%) when compared to the pre‐algorithm group 360/462 (77.9%) (P < 0.001) was also significantly improved. Failure rates were significantly lower. Efficiency parameters including procedure time, contrast volume, fluoroscopy time, and radiation doses all favored the post hybrid group but did not reach statistical significance.

Conclusions

The validation of the hybrid algorithm has the potential to disseminate adoption of CTO PCI. © 2014 Wiley Periodicals, Inc.
Sensitivity of brachial versus femoral vein injection of agitated saline to detect right‐to‐left shunts with Transcranial Doppler
Authors: Gevorgyan Rubine , Perlowski Alice , Shenoda Michael , Mojadidi M. Khalid , Agrawal Harsh , Tobis Jonathan M.
Published: January 2014

Background

Transcranial Doppler (TCD) can detect a right‐to‐left shunt (RLS) with high sensitivity but has a 5% chance of a false negative study. TCD is usually performed with injection of agitated saline into an arm vein. We compared the sensitivity of TCD performed from the brachial versus femoral veins.

Methods

Patients presenting to the cardiac catheterization laboratory for percutaneous closure of a patent foramen ovale (PFO) were enrolled. Power M‐mode Transcranial Doppler (Terumo 150 PMD) was conducted. After injection of a mixture of 8 cc of agitated saline, 0.5 cc of air, and 1 cc of blood into the brachial vein, embolic tracks were counted over the middle cerebral arteries. The degree of RLS was evaluated by TCD at rest, and with Valsalva at 40 mmHg aided by visual feedback with a manometer device. The test was repeated using femoral venous injections.

Results

Sixty five patients were enrolled, mean age 52, 43% male. TCD grades were significantly higher with femoral injections compared to brachial injections at rest (p<0.0001), and with the Valsalva maneuver (p<0.0001). The presence of a RLS was confirmed by intracardiac echocardiography (ICE) during cardiac catheterization in 62 (95.4%) patients.

Conclusion

The sensitivity of TCD for detection of RLS is increased when agitated saline injections are performed through the femoral vein. In patients with a high clinical suspicion for RLS, low TCD grades obtained with traditional brachial venous access should be interpreted with caution. When possible, a repeat study using femoral venous access may be considered. © 2014 Wiley Periodicals, Inc.
Effect of Organic Sulfide in Precursors on the Pore Structure of High‐Surface Area Activated Carbons
Authors: Zhang Huaihao , Jiang Yuanyuan , Gu Jiangna , Zhao Jing , Zhang Xiaoxing , Wang Chengyin
Published: January 2014

Analogous precursors in the presence of sulfide dibenzothiophene (DBT) were employed to prepare high‐surface area activated carbons (HAC) by KOH chemical activation, in order to investigate the influence of the DBT content on the pore structure of the resultant HAC. The results indicate that the DBT in the precursor can react with and consume a certain amount of the activation agent KOH, thus reducing the actual KOH/coke ratio, which imposes a clear negative effect on the pore structure development. However, regardless of how high the DBT content is in the precursor, no residual sulfur is found in the obtained HAC. The HAC with developed porosity can also be achieved by just increasing the KOH dosage to compensate for the amount consumed in the DBT reaction during the activation process, which provides a high value‐added utilization way for organic sulfur‐containing minerals.
Career Exploration and Perceived Employability within an Emerging Economy Context
Authors: Forstenlechner Ingo , Selim Hassan , Baruch Yehuda , Madi Mohamed
Published: January 2014

Following four decades of unprecedented economic, social, and cultural change, the United Arab Emirates (UAE) labor market is highly segmented: The native population is almost exclusively employed in the government sector, while the private sector is effectively outsourced to foreigners. This has created an unsustainable situation with growing numbers of young citizens reaching working age and with a public sector that has reached the saturation point. Policymakers repeatedly try to legislate to encourage private‐sector employers to hire citizens. These policies have had limited success. We explored the career attitudes of 2,267 United Arab Emirates citizens prior to their entry into the labor market. Using structural equation modeling, we found that the social contract and resulting expectations toward state employment have strong implications for willingness to work in the private sector. © 2014 Wiley Periodicals, Inc.
S100A1 and S100B Expression Patterns Identify Differentiation Status of Human Articular Chondrocytes
Authors: Diaz‐Romero Jose , Quintin Aurelie , Schoenholzer Eric , Pauli Chantal , Despont Alain , Zumstein Matthias A. , Kohl Sandro , Nesic Dobrila
Published: January 2014

Many studies in the field of cell‐based cartilage repair have focused on identifying markers associated with the differentiation status of human articular chondrocytes (HAC) that could predict their chondrogenic potency. A previous study from our group showed a correlation between the expression of S100 protein in HAC and their chondrogenic potential. The aims of the current study were to clarify which S100 proteins are associated with HAC differentiation status and to provide an S100‐based assay for measuring HAC chondrogenic potential. The expression patterns of S100A1 and S100B were investigated in cartilage and in HAC cultured under conditions promoting dedifferentiation (monolayer culture) or redifferentiation (pellet culture or BMP4 treatment in monolayer culture), using characterized antibodies specifically recognizing S100A1 and S100B, by immunohistochemistry, immunocytochemistry, Western blot, and gene expression analysis. S100A1 and S100B were expressed homogeneously in all cartilage zones, and decreased during dedifferentiation. S100A1, but not S100B, was re‐expressed in pellets and co‐localized with collagen II. Gene expression analysis revealed concomitant modulation of S100A1, S100B, collagen type II, and aggrecan: down‐regulation during monolayer culture and up‐regulation upon BMP4 treatment. These results strongly support an association of S100A1, and to a lesser extent S100B, with the HAC differentiated phenotype. To facilitate their potential application, we established an S100A1/B‐based flow cytometry assay for accurate assessment of HAC differentiation status. We propose S100A1 and S100B expression as a marker to develop potency assays for cartilage regeneration cell therapies, and as a redifferentiation readout in monolayer cultures aiming to investigate stimuli for chondrogenic induction. J. Cell. Physiol. 229: 1106–1117, 2014. © 2014 Wiley Periodicals, Inc.
Chromosomal microarray analysis as a first‐tier clinical diagnostic test: Estonian experience
Authors: Žilina Olga , Teek Rita , Tammur Pille , Kuuse Kati , Yakoreva Maria , Vaidla Eve , Mölter‐Väär Triin , Reimand Tiia , Kurg Ants , Õunap Katrin
Published: January 2014

Chromosomal microarray analysis (CMA) is now established as the first‐tier cytogenetic diagnostic test for fast and accurate detection of chromosomal abnormalities in patients with developmental delay/intellectual disability (DD/ID), multiple congenital anomalies (MCA), and autism spectrum disorders (ASD). We present our experience with using CMA for postnatal and prenatal diagnosis in Estonian patients during 2009–2012. Since 2011, CMA is on the official service list of the Estonian Health Insurance Fund and is performed as the first‐tier cytogenetic test for patients with DD/ID, MCA or ASD. A total of 1191 patients were analyzed, including postnatal (1072 [90%] patients and 59 [5%] family members) and prenatal referrals (60 [5%] fetuses). Abnormal results were reported in 298 (25%) patients, with a total of 351 findings (1–3 per individual): 147 (42%) deletions, 106 (30%) duplications, 89 (25%) long contiguous stretches of homozygosity (LCSH) events (>5 Mb), and nine (3%) aneuploidies. Of all findings, 143 (41%) were defined as pathogenic or likely pathogenic; for another 143 findings (41%), most of which were LCSH, the clinical significance remained unknown, while 61 (18%) reported findings can now be reclassified as benign or likely benign. Clinically relevant findings were detected in 126 (11%) patients. However, the proportion of variants of unknown clinical significance was quite high (41% of all findings). It seems that our ability to detect chromosomal abnormalities has far outpaced our ability to understand their role in disease. Thus, the interpretation of CMA findings remains a rather difficult task requiring a close collaboration between clinicians and cytogeneticists.
Evidence‐Based Management: Implications for Nonprofit Organizations
Authors: Kovner Anthony R.
Published: January 2014

The article reviews evidence‐based management and its implications for practice and teaching. My focus is on strategic decision making in nonprofit organizations. Evidence‐based management is a process that includes framing the question, finding evidence, assuring accuracy, applicability, and actionability of evidence until the evidence is the best available.
System identification and modeling of viscoelastic behavior from capillary melt rheological data
Authors: Kazmer David O.
Published: January 2014

An investigation was conducted to identify and characterize the relaxation spectrum of polymer melts from transient capillary rheological data. System identification techniques using an iterative prediction‐error minimization (PEM) method were applied to isolate the viscoelastic melt response from the apparatus dynamics. Parameters for linear time invariant (LTI) models of varying complexity were estimated using capillary rheology data across a range of temperatures and shear rates using the principle of time‐temperature superposition. Melt capillary rheology data for polystyrene was found to exhibit viscoleastic behavior. Subsequently, three viscoelastic constitutive models were then implemented and their model coefficients directly fit using optimization techniques. The implemented methods provided useful relaxation behavior from melt capillary rheology data while also explaining much of the residual error in the purely viscous response as traditionally fit to the Cross‐WLF model. POLYM. ENG. SCI., 54:2824–2838, 2014. © 2014 Society of Plastics Engineers
Massive Growth of the Invasive Algae Didymosphenia Geminata Associated with Discharges from a Mountain Reservoir Alters the Taxonomic and Functional Structure of Macroinvertebrate Community
Authors: Ladrera Rubén , Rieradevall Maria , Prat Narcís
Published: January 2014

The objective of this paper is to determine the alteration of the taxonomic composition and functional structure of macroinvertebrate community associated with a massive growth of the invasive algae Didymosphenia geminata downstream of a mountain reservoir (Pajares Reservoir, La Rioja, Northern Spain). As the massive growth of the alga disappears a few kilometres downstream of the reservoir associated with the input of nutrients from a nearby village sewage, we may compare the community composition between nine stations in three different conditions: three stations heavily affected by the presence of D. geminata, three further downstream stations without the algal massive growth but affected by river regulation and three control stations (unregulated and without the algae). Results show a significant disturbance of the composition and structure of macroinvertebrate community in sites affected by the stream flow regulation downstream of the dam compared with unregulated streams, but the alterations are more dramatic in the area where the growth of D. geminata is massive because of the total substrate occupation by the algal filaments. Scrapers and others invertebrates living on the coarse substrate are especially affected at such sites. Moreover, an important increase in the relative abundance of chironomids is associated with the algal massive growth, especially in case of Eukiefferiella devonica and Cricotopus spp., reducing the assemblage diversity and leading to the taxonomic and functional homogenization of the community. Changes in the reservoir management (such as releasing the water from surface rather than from the hypolimnion) may be useful to control the massive growth of D. geminata and thus reducing the effects of river regulation on macroinvertebrate assemblage composition. Copyright © 2014 John Wiley & Sons, Ltd.
Ultrasound imaging of the pelvic floor: changes in anatomy during and after first pregnancy
Authors: van Veelen G. A. , Schweitzer K. J. , van der Vaart C. H.
Published: January 2014

Objectives

To describe changes in the absolute values of levator hiatal dimensions and in the contractility and distensibility of the levator hiatus during pelvic floor contraction and Valsalva maneuver, using three/four‐dimensional (3D/4D) transperineal ultrasound in women during and after their first pregnancy.

Methods

Two‐hundred and eighty nulliparous pregnant women underwent ultrasound examination at 12 and 36 weeks' gestation and 6 months postpartum. Hiatal dimensions were measured at rest, on pelvic floor contraction and on Valsalva maneuver. The contractility and distensibility were determined by the difference between hiatal dimensions at rest and those on contraction or Valsalva, respectively. After exclusions, there were 231 datasets from women at rest, 199 for pelvic floor contraction and 230 for Valsalva maneuver. Data at 36 weeks' gestation and 6 months postpartum were compared with data at 12 weeks' gestation.

Results

At 36 weeks' gestation, the absolute values of hiatal dimensions and the contractility and distensibility of the levator hiatus were significantly increased compared with those at 12 weeks' gestation. Women who delivered vaginally showed a persistent significant increase in hiatal dimensions on Valsalva, whereas women who delivered by prelabor or first‐stage Cesarean section showed no significant changes in hiatal dimensions on Valsalva. After both vaginal and Cesarean section delivery, there was a persistent increase in the distensibility of the hiatus during Valsalva compared with in early pregnancy.

Conclusion

During first pregnancy, the absolute values of levator hiatal dimensions and the contractility and distensibility of the levator hiatus increase. Regardless of delivery mode, increased distensibility of the levator hiatus during Valsalva persists after childbirth. This increased pelvic floor distensibility may play a role in the development of pelvic floor dysfunction in later life. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
Increased aortic stiffness and blood pressure in non‐classic Pompe disease
Authors: Wens Stephan C. A. , Kuperus Esther , Mattace‐Raso Francesco U. S. , Kruijshaar Michelle E. , Brusse Esther , van Montfort Kees C. A. G. M. , de Boer Marjan Scheltens‐ , Sijbrands Eric J. G. , van der Ploeg Ans T. , van Doorn Pieter A.
Published: January 2014

Vascular abnormalities and glycogen accumulation in vascular smooth muscle fibres have been described in Pompe disease. Using carotid‐femoral pulse wave velocity (cfPWV), the gold standard methodology for determining aortic stiffness, we studied whether aortic stiffness is increased in patients with Pompe disease. Eighty‐four adult Pompe patients and 179 age‐ and gender‐matched volunteers participated in this cross‐sectional case‐controlled study. Intima media thickness and the distensibility of the right common carotid artery were measured using a Duplex scanner. Aortic augmentation index, central pulse pressure, aortic reflexion time and cfPWV were assessed using the SphygmoCor® system. CfPWV was higher in patients than in volunteers (8.8 versus 7.4 m/s, p < 0.001). This difference was still present after adjustment for age, gender, mean arterial blood pressure (MAP), heart rate and diabetes mellitus (p = 0.001), and was shown by subgroup analysis to apply to the 40‐59 years age group (p = 0.004) and 60+ years age group (p = 0.01), but not to younger age groups (p = 0.99). Except for a shorter aortic reflexion time (p = 0.02), indirect indicators of arterial stiffness did not differ between patients and volunteers. Relative to volunteers (20 %), more Pompe patients had a history of hypertension (36 %, p = 0.005), and the MAP was higher than in volunteers (100 versus 92 mmHg, p < 0.001). This study shows that patients with non‐classic Pompe disease have increased aortic stiffness and blood pressure. Whether this is due to glycogen accumulation requires further investigation. To reduce the potential risk of cardiovascular diseases, we recommend that blood pressure and other common cardiovascular risk factors are monitored regularly.
A prospective study of adolescent risk and protective factors for problem gambling among young adults
Authors: Scholes‐Balog Kirsty E. , Hemphill Sheryl A. , Dowling Nicki A. , Toumbourou John W.
Published: January 2014

There is a paucity of research examining prospective predictors of problem gambling. The current study utilised a large longitudinal data set (N = 2328) to examine a large range of adolescent risk and protective factors for problem gambling in young adulthood. These risk and protective factors covered the domains of the community, family, school, peer group and individual. Numerous predictors associated with the family, school and peer‐individual were statistically significant in analyses adjusted for gender and age. However, in the fully adjusted multivariate analyses, only two predictors were statistically significant. Within this model, gender (female) was associated with a reduced risk of young adult problem gambling, while family rewards for prosocial involvement moderated the risk relationship between adolescent alcohol use and young adult problem gambling. These findings highlight the importance of adolescent alcohol use and family environment as potentially modifiable predictors of young adult problem gambling.
Risk factors for severe perineal lacerations during childbirth
Authors: Pergialiotis Vasileios , Vlachos Dimitrios , Protopapas Athanasios , Pappa Kaliopi , Vlachos Georgios
Published: January 2014

Background

Severe perineal lacerations represent a significant complication of normal labor with a strong impact on quality of life.

Objectives

To identify factors that lead to the occurrence of severe perineal lacerations.

Search strategy

We searched MEDLINE, Scopus, ClinicalTrials.gov, the Cochrane Central Register of Controlled Trials, Google Scholar and reference lists from all included studies.

Selection criteria

We included prospective and retrospective observational studies.

Data collection and analysis

Predetermined data were collected and analyzed with the Mantel–Haenszel fixed‐effects model or the DerSimonian–Laird random‐effects model.

Main results

The meta‐analysis included 22 studies (n = 651 934). Women with severe perineal tears were more likely to have had heavier infants (mean difference 192.88 g [95% CI, 139.80–245.96 g]), an episiotomy (OR 3.82 [95% CI, 1.96–7.42]), or an operative vaginal delivery (OR 5.10 [95% CI, 3.33–7.83]). Epidural anesthesia (OR 1.95 [95% CI, 1.63–2.32]), labor induction (OR 1.08 [95% CI, 1.02–1.14]), and labor augmentation (OR 1.95 [95% CI, 1.56–2.44]) were also more common among women with perineal lacerations.

Conclusions

Various factors contribute to the occurrence of perineal lacerations. Future studies should consistently evaluate all examined parameters to determine their possible interrelation.
BELLIGERENT REPRISALS IN NON-INTERNATIONAL ARMED CONFLICTS
Authors: Bílková Veronika
Published: January 2014

The paper offers the first comprehensive treatment of the applicability and regulation of belligerent reprisals in non-international armed conflicts. It introduces three approaches to the topic (‘extralegal’, ‘permissive’ and ‘restrictive’ approaches) which all enjoy some support among States and scholars. The paper shows that international humanitarian law (IHL) treaties, IHL customs and other legal sources do not make it possible to decide between these approaches, as they are either silent on the topic or allow for several interpretations. It is the assessment of extralegal considerations and of the general framework of IHL which allows us to conclude that belligerent reprisals are inapplicable in non-international armed conflicts (‘extralegal’ approach). Yet, there are signs indicating that a gradual shift toward the ‘restrictive’ approach could be under way. The paper cautions against a premature acceptance of this approach drawing attention to its limits.
Molecular phylogeny resolves a taxonomic misunderstanding and placesGeisleriaclose toAbsconditellas. str. (Ostropales:Stictidaceae)
Authors: APTROOT André , PARNMEN Sittiporn , LÜCKING Robert , BALOCH Elisabeth , JUNGBLUTH Patricia , CÁCERES Marcela E. S. , LUMBSCH H. Thorsten
Published: January 2014

The phylogenetic position of the genusGeisleriaand its type speciesG. sychnogonioideswas reconstructed using sequence data of the mitochondrial small subunit (mtSSU), the nuclear large subunit rDNA (nuLSU) and the first subunit of the RNA polymerase (RPB1). The species, previously classified inVerrucariaceae(Eurotiomycetes) andStrigulaceae(Dothideomycetes), is sister to the type of the genusAbsconditella,A. sphagnorum, and nested within the generaAbsconditellaandCryptodiscuscombined (which also includes the lichenizedBryophagus). At first glance it appears to be a further example of parallel evolution of perithecioid ascomata withinStictidaceae(Lecanoromycetes:Ostropales), besidesOstropaandRobergea, adding to the growing list of perithecioid forms nested within apothecioid lineages in Ostropomycetidae, and specificallyOstropales, with other examples known fromGraphidaceae(several genera),Gyalectaceae(Belonia), andPorinaceae. However, revision of type material collected by Nitschke revealed that the species actually develops typical apothecia with a narrowly exposed disc. We conclude thatGeisleria sychnogonoideswas erroneously considered a pyrenocarpous taxon, because in dry conditions the apothecia are closed and not recognizable as such. The species usually grows on unstable soil and therefore often only develops young, more or less closed ascomata (yet with mature ascospores), and has also been confused with the superficially similarBelonia incarnata, in which the ascomata remain closed even when mature.Geisleriasychnogonioideshas so far only been known as a rarely reported pioneer species from loamy soils in Europe and North America. Here it is reported to occur abundantly on lateritic soils in subtropical Brazil, suggesting that it is cosmopolitan and possibly common, but much overlooked.