bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination and verification of the gap dependent heat transfer coefficient during permanent mold casting of A356 aluminum alloy
Authors: Ahmadein M. , Pustal B. , Wolff N. , Bührig‐Polaczek A.
Published: January 2018

In complex castings, the heat transfer across the casting / mold interface depends on the local gap size and contact pressure. Thus, an experimental setup is constructed to measure and evaluate the air‐gap dependent heat transfer coefficient during solidification of an A356 permanent mold casting. In order to evaluate the heat transfer coefficient, the temperature gradient and air gap development is measured at the casting / mold interface. This allows the interface temperatures and the time‐dependent heat flux across the gap to be calculated as a function of the measured gap size. Furthermore, the heat transfer coefficient and gap size are correlated to the interface temperature of the casting. The experimental setup and the evaluation procedure provide consistent and reproducible results. The heat transfer coefficient thus evaluated is employed to simulate the experimental setup. The temperatures measured are well reproduced. The results of the present work are compared to simulations using two heat transfer coefficient functions found in literature. This comparison shows a substantial improvement over the state of the art. This improvement is due to the exact knowledge of gap formation and the corresponding values of the heat transfer coefficient.
Characterization of macromolecular baseline of human brain using metabolite cycled semi‐LASER at 9.4T
Authors: Giapitzakis Ioannis‐Angelos , Avdievich Nikolai , Henning Anke
Published: January 2018

Purpose

Macromolecular resonances (MM) arise mainly from cytosolic proteins and overlap with metabolites, influencing metabolite quantification. Macromolecules can serve as valuable biomarkers for diseases and pathologies. The objectives of this study were to characterize MM at 9.4T in the human brain (occipital and left parietal lobe) and to describe the RF coil setup used for MM acquisition in the two regions.

Methods

An adiabatic inversion pulse was optimised for metabolite nulling at 9.4T using double inversion recovery and was combined for the first time with metabolite cycled (MC) semi‐LASER and appropriate coil configuration. MM spectra (seven volunteers) from two brain locations were averaged and smoothed creating MM templates, which were then parametrized using simulated Voigt‐shaped lines within LCModel. Quantification was performed on individual data sets, including corrections for different tissue composition and the T1 and T2 relaxation of water.

Results

Our coil configuration method resulted in efficient
(>30 T/√kW) for both brain regions. The 15 MM components were detected and quantified in MM baselines of the two brain areas. No significant differences in concentration levels of MM between different regions were found. Two new MM peaks were reported (M7 & M8).

Conclusion

Double inversion, which was combined with MC semi‐LASER, enabled the acquisition of high spectral resolution MM spectra for both brain regions at 9.4T. The 15 MM components were detected and quantified. Two new MM peaks were reported for the first time (M7 & M8) and preliminarily assigned to β‐methylene protons of aspartyl‐groups. Magn Reson Med 80:462–473, 2018. © 2018 International Society for Magnetic Resonance in Medicine.
A bayesian method for accelerated magnetic resonance elastography of the liver
Authors: Ebersole Christopher , Ahmad Rizwan , Rich Adam V. , Potter Lee C. , Dong Huiming , Kolipaka Arunark
Published: January 2018

Purpose

Magnetic resonance elastography is a noninvasive tool for quantifying soft tissue stiffness. Magnetic resonance elastography has been adopted as a clinical method for staging liver fibrosis. However, the application of liver magnetic resonance elastography requires multiple lengthy breath‐holds. We propose a new data acquisition and processing method to reduce magnetic resonance elastography scan time.

Methods

A Bayesian image reconstruction method that uses transform sparsity and magnitude consistency across different phase offsets to recover images from highly undersampled data is proposed. The method is validated using retrospectively down‐sampled phantom data and prospectively down‐sampled in vivo data (N = 86).

Results

The proposed technique allows accurate quantification of mean liver stiffness up to an acceleration factor of R = 6, enabling acquisition of a slice in 4.3 s. Bland‐Altman analysis indicates that the proposed technique (R = 6) has a bias of −0.04 kPa and limits of agreement of −0.36 to + 0.28 kPa when compared with traditional generalized autocalibrating partial parallel acquisition reconstruction (R = 1.4).

Conclusion

By exploiting transform sparsity and magnitude consistency, accurate quantification of mean stiffness in the liver can be obtained at an acceleration rate of up to R = 6. This potentially enables the collection of three to four liver slices, as per clinical protocol, within a single breath‐hold. Magn Reson Med 80:1178–1188, 2018. © 2018 International Society for Magnetic Resonance in Medicine.
Age‐associated urethral dysfunction in urethane‐anesthetized rats
Authors: Kimura Ryu , Miyazato Minoru , Ashikari Asuka , Oshiro Takuma , Saito Seiichi
Published: January 2018

Aims

We aimed to investigate the age‐associated changes in movement coordination between the urinary bladder and the urethra in rats.

Methods

A total of 17 female Sprague‐Dawley rats were used. The rats were divided into young (3 months old) and middle‐aged (12‐15 months old) groups. In both groups, isovolumetric cystometry and urethral perfusion pressure (UPP) measurements were performed under urethane anesthesia. After the rhythmic bladder contractions stabilized, L‐arginine, a nitric oxide (NO) substrate (100 mg/kg), was administered intravenously in both groups. Subsequently, N‐nitro‐L‐arginine methyl ester hydrochloride (L‐NAME) (50 mg/kg) was injected intravenously to inhibit NO synthase activity in both groups.

Results

UPP change, defined as UPP nadir minus baseline UPP, was significantly smaller in middle‐aged rats (64%) than in young rats (P < 0.05). The mean amplitude of high‐frequency oscillations (HFOs) of the external urethral sphincter was also significantly lower (62%) in middle‐aged rats than that in young rats (P < 0.05). Urethral contraction during UPP change was also noted in middle‐aged rats. This urethral contraction disappeared after L‐arginine administration. UPP nadir during bladder contraction was inhibited by L‐NAME in both groups. UPP change was greater in middle‐aged rats than in young rats, and 3 out of 9 middle‐aged rats showed a detrusor‐sphincter dyssynergia pattern after L‐NAME.

Conclusions

The results indicated that aging induces dysfunction in movement coordination between the urinary bladder and the urethra. Thus, age‐associated urethral dysfunctions may lead to inefficient voiding with increased post‐void residual urine volume, which is often observed in elderly populations.
A novel hybrid model predictive control design with application to a quadrotor helicopter
Authors: Jalili Sadegh , Rezaie Behrooz , Rahmani Zahra
Published: January 2018

In this paper, a novel control design strategy based on a hybrid model predictive control in combination with fuzzy logic control is presented for a quadrotor helicopter system. In the proposed scheme, a 2‐part control structure is used. In the first part, a linear model predictive controller with receding horizon design strategy is combined with a nonlinear model predictive controller, which is applied as the main controller. In the second part, a 2‐level fuzzy logic controller is utilized to assist the first controller when the error exceeds a predefined value. The proposed nonlinear predictive control method utilizes a novel approach in which a prediction of the future outputs is used in the modeling stage. Using this simple technique, the problem can be solved using linear methods and, thereby, due to considerable reduction in the computational cost, it will be applicable for the systems with fast dynamics. Moreover, the fuzzy logic controller is used as a supervisor to adjust a proportional‐integral‐derivative controller to enhance the system performance by decreasing the tracking error. The proposed scheme is applied to a model of quadrotor system such that the difference between the predicted output of the system and the reference value is minimized while there are some constraints on inputs and outputs of the nonlinear quadrotor system. Simulation results demonstrate the efficiency of the proposed control scheme for the quadrotor system model.
Impact of baseline clinical and laboratory features on the risk of thrombosis in children with acute lymphoblastic leukemia: A prospective evaluation
Authors: Athale Uma H. , Mizrahi T. , Laverdière C. , Nayiager T. , Delva Y.‐L. , Foster G. , Thabane L. , David M. , Leclerc J.‐M. , Chan A. K. C.
Published: January 2018

Background

Children with acute lymphoblastic leukemia (ALL) have increased risk of thromboembolism (TE). However, the predictors of ALL‐associated TE are as yet uncertain.

Objective

This exploratory, prospective cohort study evaluated the effects of clinical (age, gender, ALL risk group) and laboratory variables (hematological parameters, ABO blood group, inherited and acquired prothrombotic defects [PDs]) at diagnosis on the development of symptomatic TE (sTE) in children (aged 1 to ≤18) treated on the Dana‐Farber Cancer Institute ALL 05‐001 study.

Procedures

Samples collected prior to the start of ALL therapy were evaluated for genetic and acquired PDs (proteins C and S, antithrombin, procoagulant factors VIII (FVIII:C), IX, XI and von Willebrand factor antigen levels, gene polymorphisms of factor V G1691A, prothrombin gene G20210A and methylene tetrahydrofolate reductase C677T, anticardiolipin antibodies, fasting lipoprotein(a), and homocysteine).

Results

Of 131 enrolled patients (mean age [range] 6.4 [1–17] years) 70 were male patients and 20 patients (15%) developed sTE. Acquired or inherited PD had no impact on the risk of sTE. Multivariable analyses identified older age (odds ratio [OR] 1.13; 95% confidence interval [CI]: 1.01, 1.26) and non‐O blood group (OR 3.64, 95% CI: 1.06, 12.51) as independent predictors for development of sTE. Patients with circulating blasts had higher odds of developing sTE (OR 6.66; 95% CI: 0.82, 53.85).

Conclusion

Older age, non‐O blood group, and presence of circulating blasts, but not PDs, predicted the risk of sTE during ALL therapy. We recommend evaluation of these novel risk factors in the development of ALL‐associated TE. If confirmed, these easily accessible variables at diagnosis can help develop a risk‐prediction model for ALL‐associated TE.
A Five–Factor Theory Perspective on Causal Analysis
Authors: McCrae Robert R. , Sutin Angelina R.
Published: January 2018

Five–Factor Theory provides a broad but largely blank template for causal personality research. Within Five–Factor Theory, there are three major categories of questions: (1) how do biological structures and functions lead to trait levels? (2) how do traits and the environment give rise to acquired psychological institutions? and (3) how do personality characteristics interact with specific situations to determine behaviours and reactions? Both practical and ethical issues complicate the search for the causes of trait change. Causal explanations of the development of characteristic adaptations are likely to be incomplete, because there are many different ways in which the same adaptation may be acquired. Studies of the determinants of behaviour are usually left to social, educational, or clinical psychologists—although personality psychologists may make distinctive contributions by emphasizing the role of the individual in selecting and creating situations. A causal understanding of the functioning of the personality system is possible through the integration of many lines of evidence, but it is likely to take a very long time. In the meanwhile, personality psychologists may fruitfully pursue the identification of practical causes by which individuals with a given set of traits can optimize their adaptation. Copyright © 2018 European Association of Personality Psychology
Device physics underlying silicon heterojunction and passivating‐contact solar cells: A topical review
Authors: Chavali Raghu V. K. , De Wolf Stefaan , Alam Muhammad A.
Published: January 2018

The device physics of commercially dominant diffused‐junction silicon solar cells is well understood, allowing sophisticated optimization of this class of devices. Recently, so‐called passivating‐contact solar cell technologies have become prominent, with Kaneka setting the world's silicon solar cell efficiency record of 26.63% using silicon heterojunction contacts in an interdigitated configuration. Although passivating‐contact solar cells are remarkably efficient, their underlying device physics is not yet completely understood, not in the least because they are constructed from diverse materials that may introduce electronic barriers in the current flow. To bridge this gap in understanding, we explore the device physics of passivating contact silicon heterojunction (SHJ) solar cells. Here, we identify the key properties of heterojunctions that affect cell efficiency, analyze the dependence of key heterojunction properties on carrier transport under light and dark conditions, provide a self‐consistent multiprobe approach to extract heterojunction parameters using several characterization techniques (including dark J‐V, light J‐V, C‐V, admittance spectroscopy, and Suns‐Voc), propose design guidelines to address bottlenecks in energy production in SHJ cells, and develop a process‐to‐module modeling framework to establish the module's performance limits. We expect that our proposed guidelines resulting from this multiscale and self‐consistent framework will improve the performance of future SHJ cells as well as other passivating contact‐based solar cells.
A comparison of the 1H‐, 13C‐, and 15N‐NMR data of chlorophyll a and chlorophyll b guided by quantum chemical calculation
Authors: Najdanova Marija , Siehl Hans‐Ullrich , Berger Stefan
Published: January 2018

Chlorophyll a and chlorophyll b have been isolated and purified by counter current chromatography. The 1H‐, 13C‐, and 15N‐NMR spectra were recorded and compared for the 2 molecules by using arguments based on classical structural properties. This interpretation is fully corroborated by high‐level ab initio quantum chemical calculations.
Bioconjugated Core–Shell Microparticles for High‐Force Optical Trapping
Authors: Cordova Juan Carlos , Reinemann Dana N. , Laky Daniel J. , Hesse William R. , Tushak Sophie K. , Weltman Zane L. , Best Kelsea B. , Bardhan Rizia , Lang Matthew J.
Published: January 2018

Due to their high spatial resolution and precise application of force, optical traps are widely used to study the mechanics of biomolecules and biopolymers at the single‐molecule level. Recently, core–shell particles with optical properties that enhance their trapping ability represent promising candidates for high‐force experiments. To fully harness their properties, methods for functionalizing these particles with biocompatible handles are required. Here, a straightforward synthesis is provided for producing functional titania core–shell microparticles with proteins and nucleic acids by adding a silane–thiol chemical group to the shell surface. These particles display higher trap stiffness compared to conventional plastic beads featured in optical tweezers experiments. These core–shell microparticles are also utilized in biophysical assays such as amyloid fiber pulling and actin rupturing to demonstrate their high‐force applications. It is anticipated that the functionalized core–shells can be used to probe the mechanics of stable proteins structures that are inaccessible using current trapping techniques.
Optical and Photoelectric Properties of Nanolamellar Structures Obtained by Thermal Annealing of InSe Plates in Zn Vapours
Authors: Untila Dumitru , Evtodiev Igor , Caraman Iuliana , Spalatu Nicolae , Dmitroglo Liliana , Caraman Mihail
Published: January 2018

The structural, optical and photoelectric properties of InSe crystals grown by Bridgman–Stockbarger method and ZnSe/InSe structures obtained on InSe by thermal annealing in Zn vapours are studied in this paper. The study of structural properties confirms that ZnSe compound is formed. The analysis of photoelectric properties reveal that both the ZnSe‐InSe composite layer and the composite/InSe heterojunction are photosensitive in the VIS‐NIR spectral region.
Strain Mediated in‐Plane Uniaxial Magnetic Anisotropy in Amorphous CoFeB Films Based on Structural Phase Transitions of BaTiO3 Single‐Crystal Substrates
Authors: Isogami Shinji , Taniyama Tomoyasu
Published: January 2018

The uniaxial in‐plane magnetic anisotropy constants (K1) of amorphous Co10Fe74B16 (CoFeB) films deposited on BaTiO3 (BTO) single‐crystal substrates are characterized using a vibrating sample magnetometer. As a result, a significant increase in K1 with temperature is observed by a factor of 26, from 0.267 × 105 erg cm−3 at 300 K to 6.88 × 105 erg cm−3 at 230 K, and the thermal/K1 cycling was reproduced. Estimation of the magnetoelastic effect at the CoFeB/BTO interface demonstrated that the external stress resulting from the structural phase transition from tetragonal to orthorhombic structure in the (001) plane of BTO substrate is the primary cause of the instant magnetic anisotropy in amorphous systems with isotropic magnetostriction such as CoFeB.
Polarity‐ and Site‐Controlled Metal Organic Vapor Phase Epitaxy of 3D‐GaN on Si(111)
Authors: Blumberg Christian , Grosse Simon , Weimann Nils , Tegude Franz‐Josef , Prost Werner
Published: January 2018

A site‐ and polarity‐controlled MOVPE growth of 3D‐GaN on Si(111) substrates is established using the polarity‐dependent growth speed of GaN on an intermediate AlN layer. For hydrogenated Si or elevated AlN growth temperatures mixed‐polar growth is observed. N‐polarity could be realized on oxidized Si(111) surfaces by a reduced AlN growth temperature of TAlN = 930 °C. Specific Si crystal facets (e.g., {100}, {11}) are determined as starting points for metal‐polar growth of AlN. By site‐controlled etching in Si, we intentionally expose these additional crystal facets prior to epitaxy to obtain defined starting points for metal‐polar growth. At TAlN = 930 °C, this leads to a site‐controlled growth of metal‐polar GaN, surrounded by N‐polar AlN on Si(111). Thus both, a polarity‐ and site‐controlled epitaxial growth of 3D‐GaN is achieved. The new developed method has been applied to a large variety of structure sizes from 650 nm to 1 mm. The results are supported by a schematic model, explaining the influence of surface termination, in situ desorption, and growth conditions. This paves the way to the development of future 3D‐opto‐electronic devices, directly established on Si.
Effects of Biaxial Strains and High Pressure on the Structural, Electronic, and Vibrational Properties of DC‐HgM2Te4 (M = Al, In)
Authors: Zhang Shaobo , Shi Liwei , Huang Chuanfu , Xia Wangsuo , Zhang Lanyang , Zhu Haiyan
Published: January 2018

First‐principles calculations are performed to study the effects of biaxial strains and high pressure on the structural, electronic, and lattice dynamical properties of defect chalcopyrite HgM2Te4 (M = Al, In) semiconductors. The evolutions of optimized structural parameters, band‐gap energy, crystal‐field splitting energy, and ‐point phonon frequencies with the biaxial strain and pressure have been analyzed. The optimized lattice parameters are reasonable compared with the existing experimental results. Both compounds undergo an indirect to direct band gap transition under tensile , however, the semiconductors retain their indirect band gap character under pressure. The increasing pressure pushes the crystal‐field‐splitting hole (CH) band downwards; in contrast, the increasing biaxial strain makes the CH band shift upwards, which results in that the crystal‐field splitting energies decrease from positive to negative. The pressure‐induced softness of low‐frequency modes around the X point suggests that both compounds become dynamically instable. Atomic displacement patterns show that the high frequency modes are mainly determined by the vibrations of group‐III cations.
Anxiety associated with ciprofloxacin
Authors: Lam Y. W. Francis
Published: January 2018

Ciprofloxacin is a commonly prescribed antibiotic from the fluoroquinolone class. In general, fluoroquinolones have a wide therapeutic index with a favorable safety profile. However, use of this class of drugs has been associated with neuropsychiatric adverse effects, with clinical symptoms that include anxiety, depression, and insomnia. The following case report describes an elderly patient experiencing an exacerbation of anxiety after taking ciprofloxacin.
Neural network–based reconfiguration control for spacecraft formation in obstacle environments
Authors: Zhou Ning , Chen Riqing , Xia Yuanqing , Huang Jie , Wen Guoxing
Published: January 2018

This paper proposes an adaptive formation reconfiguration control scheme based on the leader‐follower strategy for multiple spacecraft systems. By taking the predesigned desired velocities and the trajectories as reference signals, a set of coordination tracking controllers is constructed by combining the reconstructed dynamic system and the neural network–based reconfiguration algorithm together. To avoid collisions between spacecraft and obstacles during the formation configuration process, the null space–based behavioral control is integrated into the control design. Since the spacecraft dynamics contains unknown nonlinearity and disturbance, it is challenging to make the system robust to uncertainties and improve the control precision simultaneously. To solve this problem, both the adaptive neural network strategy and the finite‐time control theory are employed. Finally, 2 simulation examples are carried out to verify the proposed algorithm, showing that the formation reconfiguration task can be executed successfully while achieving high control precision.
Moment exponential stability of stochastic nonlinear delay systems with impulse effects at random times
Authors: Hu Wei , Zhu Quanxin
Published: January 2018

In this paper, we investigate the pth moment exponential stability for a class of impulsive stochastic functional differential equations with impulses at random times. The impulsive times considered in this paper are random times that are different from those investigated in the existing literature. By using the stochastic process theory, stochastic analysis theory, Razumikhin technique, and Lyapunov method, we obtain some new criteria of the pth moment exponential stability for the related system. Finally, some examples are provided to show the effectiveness of the theoretical results.
Nickelhexacyanoferrate‐Modified Glassy Carbon Electrode as a Voltammetric and Electrochemical Impedance Spectroscopic Sensor for Thiocyanate Ion
Authors: Deka Kangkana , Das Diganta K.
Published: January 2018

Thiocyanate (SCN−) is present in humane blood serum, saliva and urine which is high in case of smokers and is used to distinguish smokers from non‐smokers. Chronically elevated level of SCN− in body fluids is toxic causing goitre, vertigo, unconsciousness etc. We have developed two modified glassy carbon (GC) electrodes by electrodeposition of (i) Nickelhexacyanoferrate (NiHCF) and (ii) NiHCF and cetyltrimethylammonium bromide (CTAB). These electrodes show new oxidation peaks at +1.100 V and +1.000 V respectively on interaction with SCN− at μM level. Change in Bode plot on impedance spectroscopic measurement is also observed. Ions Na+, K+, NO3−, SO42−, Cl− and CH3COO− do not interfere.
Band Gap Tuning in Composites of Polypyrrole Derivatives and C60Pd3 Polymer as Models for p–n Junction: A First Principle Computational Study
Authors: Goclon Jakub , Winkler Krzysztof
Published: January 2018

In this work, the electronic properties of a substituted polypyrrole (PPy−R) deposited on a palladium–fullerene polymer (C60Pd2(‐2Pd)) were obtained by first principles DFT+vdW calculations. By introducing both electron‐withdrawing (COOH) and electron‐donating (NH2) substituents into the polypyrrole chain, we modulated the HOMO and LUMO levels of PPy−R/C60Pd2(‐2Pd). Furthermore, we also determined the influence of the second COOH group in each pyrrole ring and the CH3 group linked to the nitrogen atom on the electronic properties. The calculated data show that the type of substituent, as well as the termination of the palladium–fullerene polymer, strongly influences the band gap. The general picture of the mixed systems reveals that the HOMO corresponds to that of PPy/PPy−R and the LUMO corresponds to that of C60Pd2(‐2Pd). For isolated PPy−R, the substituent strongly influences the relative position of the HOMO and LUMO levels toward the vacuum level, and, based on this fact, we can easily tune the band gap of the mixed systems. For the sake of completeness, all configurations, as well as the corresponding total binding energies, were carefully analysed and compared. The adsorption of PPy(‐R) on the Pd‐terminated C60Pd2 led to the formation of surface Py⋅⋅⋅Pd complexes that have higher binding energies than in the case of the C60‐terminated polymer. Furthermore, composites with two PPy chains on C60Pd2 (‐2Pd) were also studied.
Sulfamic Acid: A Recyclable Catalyst for the Synthesis of Triaryl‐ and Triheteroarylmethanes from Aldehydes and Activated Arenes
Authors: Li ZhongXian , Liu XiaoPei , Yin Yuanyuan , Li Yujiang , Wang Junwei , Yu XueJun
Published: January 2018

A practical route to triarylmethanes: Sulfamic acid was found to efficiently catalyze Friedel–Crafts alkylations of 2‐methyl furan or 1, 2, 4‐trimethoxybenzene with a variety of simple or functionalized aldehydes to provide di‐ or triarylmethanes in high yields. The reaction tolerated variety of substitutions and functional groups under “open‐flask”, mild and solvent‐free conditions. Moreover, the Sulfamic acid can be conveniently recycled is especially noteworthy.
Synthesis of g‐C3N4/ZnGa1.9Al0.1O4 Heterojunction Using Narrow and Wide Band Gap Material for Enhanced Photoelectrochemical Water Splitting
Authors: Islam M. Merajul , Tentu Rama D. , Basu Suddhasatwa
Published: January 2018

We fabricated visible‐light responsive g‐C3N4/ZnGa1.9Al0.1O4 heterojunction nanocomposites using narrow band gap g‐C3N4 and wide band gap mesoporous ZnGa1.9Al0.1O4 by thermolysis and hydrothermal methods. The charge‐transfer, electrons‐holes separation and its kinetics across the intimate interface of g‐C3N4/ZnGa1.9Al0.1O4 were systematically investigated using photoelectrochemical (PEC) measurements. The high‐resolution transmission electron microscopy (HR‐TEM) shows an intimate interface between g‐C3N4 and ZnGa1.9Al0.1O4 nanocrystals in the heterojunctions. The PEC measurements revealed higher photocurrent density towards water splitting in case of heterojunction prepared by thermolysis method compared to hydrothermal process without noble metal co‐catalyst with excellent stability. The remarkable water splitting activity is mainly ascribed to the least recombination rate of electrons and holes, facile kinetics and least charge‐transfer resistance. This is further confirmed by kinetic studies using Tafel slope and exchange‐current density data.
The role of senior management in opportunity formation: Direct involvement or reactive selection?
Authors: Barney Jay B. , Foss Nicolai J. , Lyngsie Jacob
Published: January 2018

Research Summary: Much research suggests that entrepreneurial opportunities in established firms result from bottom‐up initiative in a diverse workforce, senior management's main role in the entrepreneurial process is to select among opportunities generated in the bottom‐up process, and it should refrain from directly getting involved in this process. We develop an alternative and more active view of the role of senior management in the opportunity formation process in which senior management intervenes in the entrepreneurial process to resolve coordination and collaboration problems across initiatives and decide on resource allocation. We proffer rival hypotheses concerning the effect of such senior management involvement in the entrepreneurial process. Specifically, we hypothesize that the positive relations between bottom‐up initiative/employee diversity and opportunity formation are positively (negatively) moderated by such direct involvement by senior management. We examine these ideas using two matched data sources: a double‐respondent survey of CEOs and HR managers and employer–employee register data. We find support for the view that senior management involvement positively moderates the relations between bottom‐up processes/diversity and opportunity formation.

Managerial Summary: What are the processes through which entrepreneurial opportunities emerge in established companies? Research has pointed to diversity and bottom‐up initiative, but our understanding is limited with respect to what senior managers should do to optimally promote entrepreneurship in such companies. In one view, senior management should keep a distance and limit their involvement to picking the best opportunities out of those they are presented with in the bottom‐up process. In contrast, we argue that given bottom‐up initiative in the context of a diverse workforce, senior management should play a more direct role in the entrepreneurial process. The reason is that senior‐management involvement at early stages of the opportunity formation process is required to handle the management challenges arising from diversity and bottom‐up initiative. Overall, our study suggests that firms that wish to seize the potential benefits (in terms of entrepreneurial opportunities) of having a more diverse workforce and more bottom‐up initiative need senior managers that directly engage in the entrepreneurial process.
Microfluidic Templated Multicompartment Microgels for 3D Encapsulation and Pairing of Single Cells
Authors: Zhang Liyuan , Chen Kaiwen , Zhang Haoyue , Pang Bo , Choi Chang‐Hyung , Mao Angelo S. , Liao Hongbing , Utech Stefanie , Mooney David J. , Wang Huanan , Weitz David A.
Published: January 2018

Controlled encapsulation and pairing of single cells within a confined 3D matrix can enable the replication of the highly ordered cellular structure of human tissues. Microgels with independently controlled compartments that can encapsulate cells within separately confined hydrogel matrices would provide precise control over the route of pairing single cells. Here, a one‐step microfluidic method is presented to generate monodisperse multicompartment microgels that can be used as a 3D matrix to pair single cells in a highly biocompatible manner. A method is presented to induce microgels formation on chip, followed by direct extraction of the microgels from oil phase, thereby avoiding prolonged exposure of the microgels to the oil. It is further demonstrated that by entrapping stem cells with niche cells within separate but adjacent compartments of the microgels, it can create complex stem cell niche microenvironments in a controlled manner, which can serve as a useful tool for the study of cell–cell interactions. This microfluidic technique represents a significant step toward high‐throughput single cells encapsulation and pairing for the study of intercellular communications at single cell level, which is of significant importance for cell biology, stem cell therapy, and tissue engineering.
Faculty Performance and Morale in Higher Education: A Systems Approach
Authors: Kim Hyunjung , Rehg Michael
Published: January 2018

Universities face problems that are complex and dynamic, which makes strategic planning particularly difficult. Traditional planning approaches in universities could be improved using systems approaches. In this paper, we present systems maps and insights from a series of participatory systems mapping sessions in a higher education institution. More specifically, we discuss key issues of faculty performance and morale. We look at how innovation attempts for improving quality and efficiency of education affect faculty morale. Then we explain unintended consequences of faculty hiring decisions. Finally, we discuss the issue of faculty salary inequity and how it may lead to performance and financial problems. We believe these maps will be of value to higher education administrators seeking to support faculty success and looking for ways to enhance their strategic planning process. Our study encourages a wider application of systems approaches as planning tools for higher education. Copyright © 2018 John Wiley & Sons, Ltd.
Versagen eines Regallagers in Athen
Authors: Vayas Ioannis , Avgerinou Stella , Thanopoulos Pavlos
Published: January 2018

Palettenregalsysteme weisen besondere Merkmale gegenüber üblichen Hochbauten auf, so dass sie ganz empfindlich auf Stabilitätsversagen reagieren. Hier wird ein Versagensfall vorgestellt, bei dem ein Regallager durch Biegedrillknicken seiner meistbelasteten Stützen versagt hat. Das Tragwerksverhalten wird mit Hilfe einer Kombination von experimentellen und rechnerischen Untersuchungen analysiert. Es werden Probebelastungen, Biegeversuche an Trägern, Druckversuche an kurzen Stützen und Versuche an Träger‐Stützen‐Verbindungen durchgeführt. Anschließend wird eine globale geometrisch nichtlineare Berechnung durchgeführt, deren Ergebnisse weitgehend mit den Bildern des Versagens übereinstimmen. Es werden Lehren gezogen, die auf statische und dynamische Berechnungen und deren Prüfung auf verbindlicher Basis hinausgehen.
Anwendungsgrenzen für eine teilweise Verdübelung von Verbundträgern mit oberflanschlosen Stahlprofilen und Verbunddübelleisten
Authors: Classen Martin , Wieneke Katrin , Komor Bernard
Published: January 2018

Im EC4 sind Anwendungsgrenzen für die plastische Biegebemessung teilverdübelter Verbundträger geregelt. Neben ausreichender Verbundmittelduktilität (die Kopfbolzendübel müssen ein Verformungsvermögen von mindestens 6 mm besitzen) wird gefordert, dass die Stahlträger identische oder maximal um den dreifachen Wert abweichende Flanschflächen von Ober‐ und Untergurt aufweisen. Darüber hinaus ist eine untere Grenze für die Schubtragfähigkeit der Verbundfuge (Mindestverdübelungsgrad) definiert. Für Verbundträger mit oberflanschlosen Stahlträgern und Verbunddübelleisten wurden entsprechende Anwendungsgrenzen bisher nicht erforscht. Aufgrund deutlicher Unterschiede im Hinblick auf die Querschnittsform des Stahlprofils und das Verformungsverhalten der Verbundmittel ist eine einfache Übertragung der Regeln aus EC4 allerdings nicht möglich und voraussichtlich unsicher. Im Rahmen des ersten von zwei Fachaufsätzen zu diesem Thema werden die theoretischen Grundlagen und die Untersuchungsmethodik zur Herleitung von Anwendungsgrenzen für den Teilverbund erläutert. Neben der plastischen Biegebemessung nach Teilverbundtheorie für verschiedene Querschnitte werden nichtlineare, dreidimensionale FE‐Modelle für Verbundträger mit oberflanschlosen Stahlträgern und Verbunddübelleisten entwickelt und an Versuchen aus der Literatur validiert.
Improving lazy abstraction for SCR specifications through constraint relaxation
Authors: Degiovanni Renzo , Ponzio Pablo , Aguirre Nazareno , Frias Marcelo
Published: January 2018

Formal requirements specifications, eg, software cost reduction (SCR) specifications, are challenging to analyse using automated techniques such as model checking. Since such specifications are meant to capture requirements, they tend to refer to real‐world magnitudes often characterized through variables over large domains. At the same time, they feature a high degree of nondeterminism, as opposed to other analysis contexts such as (sequential) program verification. This makes model checking of SCR specifications difficult even for symbolic approaches. Moreover, automated abstraction refinement techniques such as counterexample guided abstraction refinement fail in many cases in this context, since the concrete state space is typically large, and reaching specific states of interest may require complex executions involving many different states, causing these approaches to perform many abstraction refinements, and making them ineffective in practice. In this paper, an approach to tackle the above situation, through a 2‐stage abstraction, is presented. The specification is first relaxed, by disregarding the constraints imposed in the specification by physical laws or by the environment, before being fed to a counterexample guided abstraction refinement procedure, tailored to SCR. By relaxing the original specification, shorter spurious counterexamples are produced, favouring the abstraction refinement through the introduction of fewer abstraction predicates. Then, when a counterexample is concretizable with respect to the relaxed (concrete) specification but it is spurious with respect to the original specification, an efficient though incomplete refinement step is applied to the constraints, to cause the removal of the spurious case. This approach is experimentally assessed, comparing it with related techniques in the verification of properties and in automated test case generation, using various SCR specifications drawn from the literature as case studies. The experiments show that this new approach runs faster and scales better to larger, more complex specifications than related techniques.
An Online Faulty Sub‐Feeder Identification Method for the NUGS Single‐Phase Earth Fault Based on the Faulty Phase Current Feature Recognition
Authors: Lin Xiangning , Liu Peng , Lyu Ran , Li Zhengtian , Weng Hanli , Huang Jingguang , Tong Ning
Published: January 2018

Single‐phase earthing is a type of fault that occurs frequently in a distribution network. To improve the reliability of the power supply, neutral un‐effectively grounded system (NUGS) is adopted in many countries. However, it will lead to the difficulty of identification of the faulted components. Existing faulty sub‐feeder identification methods place severe limit on field feasibility in various aspects when dealing with this problem. In this paper, an online single‐phase earth faulty sub‐feeder identification method based on the faulty phase current feature recognition is introduced and assessed according to the universal distribution characteristics of the high‐frequency transient components. In comparison with existing location methods, the proposed method is independent of zero‐sequence current measurement and has the natural faulty feeder selection capability. Besides, it can be implemented economically by virtue of the existing distribution automation system in the NUGS. The effectiveness of the proposed method under various fault conditions is verified by Power Systems Computer Aided Design/Electromagnetic Transients including DC (PSCAD/EMTDC) simulation and comparison studies. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Trade and the organization of production: Efficiency and labour market outcomes
Authors: Viegelahn Christian , Wang Zheng , Soete Sophie , Delautre Guillaume
Published: January 2018

This chapter presents novel estimates on the numbers and shares of workers in exporting and importing firms of the formal private sector in 132 countries. It shows that the share of workers employed by exporting firms dropped significantly during the trade collapse caused by the global economic crisis and has stagnated ever since. For the same set of countries, the chapter also documents that exporters and importers are more productive and pay higher wages than their non‐trading counterparts. There is, however, a gap between the productivity and the wage premium of exporting and importing firms, indicating that gains from trade are only partially translated into gains for workers. Within exporting firms, heavy exporters tend to have lower labour productivity and pay lower wages than other exporters, while firms that supply inputs into GSCs have higher productivity and pay higher wages than other exporters. Exporters, especially those that form part of GSCs by assembling final goods, employ more women than non‐exporters, but at the same time tend to have higher shares of temporary employment. Importers are found to employ fewer temporary workers.
Pharmacokinetics, Antiviral Activity, and Safety of Rilpivirine in Pregnant Women with HIV-1 Infection: Results of a Phase 3b, Multicenter, Open-Label Study
Authors: Osiyemi Olayemi , Yasin Salih , Zorrilla Carmen , Bicer Ceyhun , Hillewaert Vera , Brown Kimberley , Crauwels Herta M.
Published: January 2018

Introduction

Physiologic changes during pregnancy may impact the pharmacokinetics of drugs. In addition, efficacy and safety/tolerability concerns have been identified for some antiretroviral agents.

Methods

Human immunodeficiency virus (HIV)-1–infected pregnant women (18–26 weeks gestation) receiving the non-nucleoside reverse transcriptase inhibitor rilpivirine 25 mg once daily were enrolled in this phase 3b, open-label study examining the impact of pregnancy on the pharmacokinetics of rilpivirine when it is given in combination with other antiretroviral agents. Blood samples (collected over the 24-h dosing interval) to assess total and unbound rilpivirine plasma concentrations were obtained during the second and third trimesters (24–28 and 34–38 weeks gestation, respectively) and 6–12 weeks postpartum. Pharmacokinetic parameters were derived using noncompartmental analysis and compared (pregnancy versus postpartum) using linear mixed effects modeling. Antiviral and immunologic response and safety were assessed.

Results

Nineteen women were enrolled; 15 had evaluable pharmacokinetic results. Total rilpivirine exposure was 29–31% lower during pregnancy versus postpartum; differences were less pronounced for unbound (pharmacodynamically active) rilpivirine. At study entry, 12/19 (63.2%) women were virologically suppressed; 10/12 (83.3%) women were suppressed at the postpartum visit. Twelve infants were born to the 12 women who completed the study (7 discontinued); no perinatal viral transmission was observed among 10 infants with available data. Rilpivirine was generally safe and well tolerated in women and infants exposed in utero.

Conclusion

Despite decreased rilpivirine exposure during pregnancy, treatment was effective in preventing mother-to-child transmission and suppressing HIV-1 RNA in pregnant women. Results suggest that rilpivirine 25 mg once daily, as part of individualized combination antiretroviral therapy, may be an appropriate option for HIV-1–infected pregnant women.

Trial Registration

ClinicalTrials.gov Identifier, NCT00855335.
Making Sense of Data Analytic Techniques used in a Cochrane Systematic Review
Authors: Gertler Paul , Cameron Ian D.
Published: January 2018

Systematic reviews have developed over the past 40 years as a method for integrating findings from the available studies relating to clinical problems and interventions into one publication. Systematic reviews employ a variety of data analytic techniques including meta-analysis, which combines treatment effects across disparate studies in order to produce a truer estimate of treatment effect. The Cochrane Collaboration was established in order to facilitate access to high-quality evidence and specifies stringent guidelines for the production of systematic reviews. A Cochrane Systematic Review (CSR) includes consideration of the risk-of-bias of the selected studies in reaching conclusions. A recent CSR is used as an example to demonstrate the process of conducting a CSR, the data analytic methods employed and the assumptions made when employing these methods. There is a discussion of issues the reader will need to be aware of when considering the findings of a CSR and how this might differ from other systematic reviews including some consideration of how CSRs apply to the brain impairment literature.
PARTY CARTELIZATION, INDONESIAN-STYLE: PRESIDENTIAL POWER-SHARING AND THE CONTINGENCY OF DEMOCRATIC OPPOSITION
Authors: Slater Dan
Published: January 2018

Democracy and opposition are supposed to go hand in hand. Opposition did not emerge as automatically as expected after Indonesia democratized, however, because presidents shared power much more widely than expected. The result has been what I call party cartelization, Indonesian-style. This differs significantly from canonical cases of party cartelization in Europe. Yet it exhibits the same troubling outcome for democratic accountability: the stunted development of a clearly identifiable party opposition. Since the advent of direct presidential elections in 2004, Indonesian democratic competition has unsurprisingly assumed somewhat more of a government vs. opposition cast. But this shift has arisen more from contingent failures of elite bargaining than from any decisive change in the power-sharing game. So long as Indonesia's presidents consider it strategically advantageous to share power with any party that declares its support, opposition will remain difficult to identify and vulnerable to being extinguished entirely in the world's largest emerging democracy.
Defining the Scope of Free Movement of Citizens in the East African Community: The East African Court of Justice and its Interpretive Approach
Authors: Nalule Caroline
Published: January 2018

Free movement of persons is one of the core tenets of the East African Community (EAC) common market, making it seem like a purely economic project. However the EAC ultimately aims to constitute itself as a political federation. This article argues that the free movement of persons within the EAC should be interpreted in broad terms with the aim of asserting it as a fundamental right of EAC citizens. Such an interpretation should be championed by the East African Court of Justice, whose mandate is the interpretation and application of community law. The court, however, seems to prefer a narrow, textual and cautious interpretive approach that may not necessarily advance the EAC's broader objectives. A human rights-oriented interpretive approach might just be the key to realizing a progressive transformation in the rationalization of the right to free movement within the EAC.
Improved exogenous DNA uptake in bovine spermatozoa and gene expression in embryos using membrane destabilizing agents in ICSI-SMGT
Authors: Sánchez-Villalba Esther , Arias María Elena , Zambrano Fabiola , Loren Pía , Felmer Ricardo
Published: January 2018

Sperm-mediated gene transfer (SMGT) is a simple, fast, and economical biotechnological tool for producing transgenic animals. However, transgene expression with this technique in bovine embryos is still inefficient due to low uptake and binding of exogenous DNA in spermatozoa. The present study evaluated the effects of sperm membrane destabilization on the binding capacity, location and quantity of bound exogenous DNA in cryopreserved bovine spermatozoa using Triton X-100 (TX-100), lysolecithin (LL) and sodium hydroxide (NaOH). Effects of these treatments were also evaluated by intracytoplasmic sperm injection (ICSI)-SMGT. Results showed that all treatments bound exogenous DNA to spermatozoa including the control. Spermatozoa treated with different membrane destabilizing agents bound the exogenous DNA throughout the head and tail of spermatozoa, compared with the control, in which binding occurred mainly in the post-acrosomal region and tail. The amount of exogenous DNA bound to spermatozoa was much higher for the different sperm treatments than the control (P < 0.05), most likely due to the damage induced by these treatments to the plasma and acrosomal membranes. Exogenous gene expression in embryos was also improved by these treatments. These results demonstrated that sperm membrane destabilization could be a novel strategy in bovine SMGT protocols for the generation of transgenic embryos by ICSI.