bluuebunny/crossref_metadata_2025 huggingface dataset:
Field effect transistors with layered two-dimensional SnS2−xSex conduction channels: Effects of selenium substitution
Authors: Pan T. S. , De D. , Manongdo J. , Guloy A. M. , Hadjiev V. G. , Lin Y. , Peng H. B.
Published: August 2013

A thorough characterization of field effect transistors with conduction channels made of SnS2−xSex nanocrystals having different selenium content is presented. The main effect of increasing the selenium content is a suppression of the drain-source current modulation by the gate voltage. The temperature dependence of SnS2−xSex conductivity for all compositions is characterized by an activation energy that gradually decreases with x. A simple donor model, with parameters of SnS2 and SnSe2 deduced from density functional theory, suggests that the change in the activation energy is mostly due to enhanced dielectric constants that accompany the band gap reduction in SnS2−xSex.
Interfacial band configuration and electrical properties of LaAlO3/Al2O3/hydrogenated-diamond metal-oxide-semiconductor field effect transistors
Authors: Liu J. W. , Liao M. Y. , Imura M. , Oosato H. , Watanabe E. , Tanaka A. , Iwai H. , Koide Y.
Published: August 2013

In order to search a gate dielectric with high permittivity on hydrogenated-diamond (H-diamond), LaAlO3 films with thin Al2O3 buffer layers are fabricated on the H-diamond epilayers by sputtering-deposition (SD) and atomic layer deposition (ALD) techniques, respectively. Interfacial band configuration and electrical properties of the SD-LaAlO3/ALD-Al2O3/H-diamond metal-oxide-semiconductor field effect transistors (MOSFETs) with gate lengths of 10, 20, and 30 μm have been investigated. The valence and conduction band offsets of the SD-LaAlO3/ALD-Al2O3 structure are measured by X-ray photoelectron spectroscopy to be 1.1 ± 0.2 and 1.6 ± 0.2 eV, respectively. The valence band discontinuity between H-diamond and LaAlO3 is evaluated to be 4.0 ± 0.2 eV, showing that the MOS structure acts as the gate which controls a hole carrier density. The leakage current density of the SD-LaAlO3/ALD-Al2O3/H-diamond MOS diode is smaller than 10−8 A cm−2 at gate bias from −4 to 2 V. The capacitance-voltage curve in the depletion mode shows sharp dependence, small flat band voltage, and small hysteresis shift, which implies low positive and trapped charge densities. The MOSFETs show p-type channel and complete normally off characteristics with threshold voltages changing from −3.6 ± 0.1 to −5.0 ± 0.1 V dependent on the gate length. The drain current maximum and the extrinsic transconductance of the MOSFET with gate length of 10 μm are −7.5 mA mm−1 and 2.3 ± 0.1 mS mm−1, respectively. The enhancement mode SD-LaAlO3/ALD-Al2O3/H-diamond MOSFET is concluded to be suitable for the applications of high power and high frequency electrical devices.
Instability of mixed convection in a vertical porous channel with uniform wall heat flux
Authors: Barletta A.
Published: August 2013

Mixed convection in a vertical plane channel filled with a saturated porous medium is investigated. The boundary planes are considered as subject to symmetric uniform heat fluxes, resulting into a net fluid heating or cooling. Either upflow or downflow conditions are considered, thus exhibiting two distinct regimes: buoyancy-assisted and buoyancy-opposed. A basic stationary and parallel flow directed vertically along the channel is examined. The linear stability of this basic solution is developed through the standard normal-mode analysis. The solution of the eigenvalue problem for neutral stability is carried out numerically for the general oblique modes. An analytical solution is provided for the longitudinal modes, with a horizontal wave vector having a direction parallel to the boundary planes. An asymptotic analytical solution is also allowed for oblique modes with either a vanishingly small Péclet number or a vanishingly small wave number. The longitudinal modes are the most unstable, displaying their parametric domain of instability under buoyancy-opposed regime. In this regime, the longitudinal modes with sufficiently small wave numbers are always unstable. This conclusion suggests that conditions of flow reversal or crossing of parametric singularities, characteristic of the parallel flow solution under buoyancy-opposed regime, are unlikely to be observed in an experiment.
Assessment of mesoscopic particle-based methods in microfluidic geometries
Authors: Zhao Tongyang , Wang Xiaogong , Jiang Lei , Larson Ronald G.
Published: August 2013

We assess the accuracy and efficiency of two particle-based mesoscopic simulation methods, namely, Dissipative Particle Dynamics (DPD) and Stochastic Rotation Dynamics (SRD) for predicting a complex flow in a microfluidic geometry. Since both DPD and SRD use soft or weakly interacting particles to carry momentum, both methods contain unavoidable inertial effects and unphysically high fluid compressibility. To assess these effects, we compare the predictions of DPD and SRD for both an exact Stokes-flow solution and nearly exact solutions at finite Reynolds numbers from the finite element method for flow in a straight channel with periodic slip boundary conditions. This flow represents a periodic electro-osmotic flow, which is a complex flow with an analytical solution for zero Reynolds number. We find that SRD is roughly ten-fold faster than DPD in predicting the flow field, with better accuracy at low Reynolds numbers. However, SRD has more severe problems with compressibility effects than does DPD, which limits the Reynolds numbers attainable in SRD to around 25–50, while DPD can achieve Re higher than this before compressibility effects become too large. However, since the SRD method runs much faster than DPD does, we can afford to enlarge the number of grid cells in SRD to reduce the fluid compressibility at high Reynolds number. Our simulations provide a method to estimate the range of conditions for which SRD or DPD is preferable for mesoscopic simulations.
A simple and reliable technique to characterize amplitude to phase modulation distortion for high-frequency amplifiers and nonlinear devices
Authors: Jauregui Rigoberto , Portilla Joaquin , Reynoso-Hernández J. A. , Hirata-Flores F. I.
Published: August 2013

This paper presents a simple and reliable measurement system for characterizing the amplitude to phase modulation (AM-PM) characteristics of high frequency amplifiers and nonlinear devices. The AM-PM measurement system is based on a null detector implemented with a double balanced mixer, and requires a voltmeter and a calibrated phase shifter. A 12 W class A radio frequency power amplifier has been designed using a GaN transistor, and the AM-PM has been measured using both the method proposed in this work and the classical method with a calibrated vector network analyzer. A good correlation between both methods is observed, which validates the proposed method.
Micro-sphere layered targets efficiency in laser driven proton acceleration
Authors: Floquet V. , Klimo O. , Psikal J. , Velyhan A. , Limpouch J. , Proska J. , Novotny F. , Stolcova L. , Macchi A. , Sgattoni A. , Vassura L. , Labate L. , Baffigi F. , Gizzi L. A. , Martin Ph. , Ceccotti T.
Published: August 2013

Proton acceleration from the interaction of high contrast, 25 fs laser pulses at >1019 W/cm2 intensity with plastic foils covered with a single layer of regularly packed micro-spheres has been investigated experimentally. The proton cut-off energy has been measured as a function of the micro-sphere size and laser incidence angle for different substrate thickness, and for both P and S polarization. The presence of micro-spheres with a size comparable to the laser wavelength allows to increase the proton cut-off energy for both polarizations at small angles of incidence (10∘). For large angles of incidence, however, proton energy enhancement with respect to flat targets is absent. Analysis of electron trajectories in particle-in-cell simulations highlights the role of the surface geometry in the heating of electrons.
Magnetic focusing with quantum point contacts in the non-equilibrium transport regime
Authors: Chen T.-M. , Pepper M. , Farrer I. , Ritchie D. A. , Jones G. A. C.
Published: August 2013

We report an experimental investigation of magnetic focusing in the 1D non-equilibrium transport regime and utilize it to study the energy variation of electrons propagating through a quantum point contact. The results give insight into the behavior of electrons with different energies when current is both unidirectional and bidirectional, in particular, a splitting of the focusing peaks which demonstrates that the intrinsic resistance within the point contact is negligible and that the voltage drop is at least 3 μm away from the ends of the point contact.
GaAs nanowires grown on Al-doped ZnO buffer layer
Authors: Haggren Tuomas , Perros Alexander , Dhaka Veer , Huhtio Teppo , Jussila Henri , Jiang Hua , Ruoho Mikko , Kakko Joona-Pekko , Kauppinen Esko , Lipsanen Harri
Published: August 2013

We report a pathway to grow GaAs nanowires on a variety of substrates using a combination of atomic layer deposition and metallo-organic vapor phase epitaxy (MOVPE). GaAs nanowires were grown via MOVPE at 430–540 °C on an atomic-layer-deposited Al:ZnO buffer layer. The resulting nanowires were affected only by the properties of the buffer layer, allowing nanowire growth on a number of substrates that withstand ∼400 °C. The growth occurred in two phases: initial in-plane growth and subsequent out-plane growth. The nanowires grown exhibited a strong photoluminescence signal both at room temperature and at 12 K. The 12 K photoluminescence peak was at 1.47 eV, which was attributed to Zn autodoping from the buffer layer. The crystal structure was zincblende plagued with either twin planes or diagonal defect planes, which were related to perturbations in the seed particle during the growth. The used method combines substrates with variable properties to nanowire growth on a transparent and conductive Al:ZnO buffer layer.
Postural Responses Accompanying Achilles Tendon Vibration Stimulation during Various Phases of Sit-to-Stand Movement
Authors: Kurokawa Nozomi , Fujiwara Katsuo , Kiyota Naoe
Published: August 2013

The aim of this study was to determine the postural response accompanying Achilles tendon vibration stimulation during various phases of the sit-to-stand movement. Twelve healthy young adults performed the sit-to-stand movement in response to an auditory signal 2 s after a first one. Vibration stimulation with a 100 Hz frequency was applied to both Achilles tendons during the following phases: (1) 10 s of sitting before standing up; (2) 10 s plus a period until the standing position was achieved; and (3) 5 s after standing. The postural response after standing was analyzed with the center of foot pressure in the anteroposterior direction. Forward-leaning responses were identified in 78.3% and 63.3% of trials under conditions 1 and 2, respectively. Backward-leaning responses were identified in 93.3% of the trials under condition 3. Response latency (± standard deviation) was significantly longer under conditions 1 and 2 than under condition 3 (1: 872 ± 576, 2: 1026 ± 542, and 3: 555 ± 322 ms; ps < 0.05). Sensory information at the standing point might be anticipated based on sensory information received while sitting. Consequently, postural response as a compensatory movement would occur via the sensory reference system within the supraspinal nervous system.
Lysine requirement of 1.5–5.5 kg pigs fed liquid diets
Authors: Eisemann J. H. , Lewis H. E. , Broome A. I. , Sullivan K. , Boyd R. D. , Odle J. , Harrell R. J.
Published: August 2013

An experiment was conducted to define the lysine requirement of neonatal pigs fed a liquid diet up to 5.5 kg bodyweight (BW). Neonatal pigs, 1–2 days old, with an initial bodyweight of 1.63 ± 0.04 kg, were randomly allotted to 10 isocaloric diets varying in lysine concentration from 0.76 to 1.62 g lysine/MJ gross energy (GE). Diets were formulated using whey protein concentrate and casein as protein sources and contained similar balance of indispensable amino acids. On day 1 of the experiment, pigs were fed 350 g liquid diet/kg metabolic bodyweight (BW0.75) according to the average BW of all pigs. On day 2, feeding rate was increased to 400 g/kg BW0.75. Increments were 100 g/kg BW0.75 per day for the subsequent 3 days until pigs reached 700 g/kg BW0.75 on day 5. Thereafter, feed was offered to pigs at a common feeding level of 700 g/kg BW0.75 each day until they reached 5.5 kg BW. Feed intake and BW were measured daily. Concentration of fat in the carcass decreased (P < 0.05) and the ratio of crude protein (CP) to fat in the carcass increased (P < 0.05) linearly as lysine inclusion increased. Both average daily gain and CP accretion increased (quadratic, P < 0.05), whereas fat accretion decreased (quadratic, P < 0.05) as lysine inclusion increased. Using the maximum point of the quadratic function, the estimated dietary lysine required for maximal growth (271 g/day) and CP accretion (45.2 g/day) was 1.41 and 1.32 g lysine/MJ GE, respectively. The dietary lysine required, estimating the requirement at the lower limit of the 95% confidence interval for CP accretion of 42.9 g/day, was 1.12 g lysine/MJ GE. Gross efficiency of CP deposition (CP deposition/CP intake) achieved a maximum of 0.85 at 1.01 g lysine/MJ GE.
Characterisation of Germanium Monohalides by Solid-State NMR Spectroscopy and First Principles Quantum Chemical Calculations
Authors: Hanson Margaret A. , Schnepf Andreas , Terskikh Victor V. , Huang Yining , Baines Kim M.
Published: August 2013

Germanium(i) monohalides are useful starting materials to synthesise small, well defined germanium nanoclusters. However, due to the amorphous nature of solid GeBr and GeCl, details of their solid-state structures remain largely unknown. We investigate the arrangement within these novel binary materials using 35Cl, 79Br, and 73Ge solid-state NMR spectroscopy at 21.1 T and first principles quantum chemical calculations in order to suggest a possible model for the structure.
Recovery of a top predator mediates negative eutrophic effects on seagrass
Authors: Hughes Brent B. , Eby Ron , Van Dyke Eric , Tinker M. Tim , Marks Corina I. , Johnson Kenneth S. , Wasson Kerstin
Published: August 2013

Significance

Many coastal vegetated ecosystems have declined, affected by human alterations to “bottom-up” forces such as nutrient loading from agriculture and by “top-down” forces such as overfishing of predators. Examining the interactions between such bottom-up and top-down changes is challenging, because top predators have disappeared from many of these ecosystems. A highly nutrient-loaded estuary in California recently colonized by a recovering sea otter population provided an unusual opportunity to examine these interactions. We demonstrate that top-down effects of sea otters mitigate negative effects of nutrient loading, enhancing growth of seagrass. Grazers that remove algae from seagrass are favored by decreased crabs resulting from otter predation. Recovery of top predators can thus support resilience of coastal vegetated ecosystems.
Integration of mTOR and estrogen–ERK2 signaling in lymphangioleiomyomatosis pathogenesis
Authors: Gu Xiaoxiao , Yu Jane J. , Ilter Didem , Blenis Nickolas , Henske Elizabeth Petri , Blenis John
Published: August 2013

Lymphangioleiomyomatosis (LAM) is a destructive lung disease of women associated with the metastasis of tuberin-null cells with hyperactive mammalian target of rapamycin complex 1 (mTORC1) activity. Clinical trials with the mTORC1 inhibitor rapamycin have revealed partial efficacy but are not curative. Pregnancy appears to exacerbate LAM, suggesting that estrogen (E
2
) may play a role in the unique features of LAM. Using a LAM patient-derived cell line (bearing biallelic Tuberin inactivation), we demonstrate that E
2
stimulates a robust and biphasic activation of ERK2 and transcription of the late response-gene
Fra1
associated with epithelial-to-mesenchymal transition. In a carefully orchestrated collaboration, activated mTORC1/S6K1 signaling enhances the efficiency of
Fra1
translation of
Fra1
mRNA transcribed by the E
2
–ERK2 pathway, through the phosphorylation of the S6K1-dependent eukaryotic translation initiation factor 4B. Our results indicate that targeting the E
2
–ERK pathway in combination with the mTORC1 pathway may be an effective combination therapy for LAM.
Inferring nucleosome positions with their histone mark annotation from ChIP data
Authors: Mammana Alessandro , Vingron Martin , Chung Ho-Ryun
Published: August 2013

Motivation: The nucleosome is the basic repeating unit of chromatin. It contains two copies each of the four core histones H2A, H2B, H3 and H4 and about 147 bp of DNA. The residues of the histone proteins are subject to numerous post-translational modifications, such as methylation or acetylation. Chromatin immunoprecipitiation followed by sequencing (ChIP-seq) is a technique that provides genome-wide occupancy data of these modified histone proteins, and it requires appropriate computational methods.

Results: We present NucHunter, an algorithm that uses the data from ChIP-seq experiments directed against many histone modifications to infer positioned nucleosomes. NucHunter annotates each of these nucleosomes with the intensities of the histone modifications. We demonstrate that these annotations can be used to infer nucleosomal states with distinct correlations to underlying genomic features and chromatin-related processes, such as transcriptional start sites, enhancers, elongation by RNA polymerase II and chromatin-mediated repression. Thus, NucHunter is a versatile tool that can be used to predict positioned nucleosomes from a panel of histone modification ChIP-seq experiments and infer distinct histone modification patterns associated to different chromatin states.

Availability: The software is available at http://epigen.molgen.mpg.de/nuchunter/.

Contact:  chung@molgen.mpg.de

Supplementary information:  Supplementary data are available at Bioinformatics online.
Poststernotomy Mediastinitis and the Role of Broken Steel Wires: Retrospective Study
Authors: Meeks Michelle D.M.E. , Lozekoot Pieter W.J. , Verstraeten Stefan E. , Nelis Mischa , Maessen Jos G.
Published: August 2013

Objective

Mediastinitis is a severe complication of cardiac surgery. Sternal instability is concomitantly present in most cases. Broken steel wires may cause sternal instability. In this study, the role of broken steel wires in sternal closure was evaluated in patients who developed poststernotomy mediastinitis.

Methods

Preoperative, perioperative, and postoperative data of patients who underwent thoracic surgery between 1996 and 2006 were retrieved from the SUMMIT registry database. Patients needing reoperation for mediastinitis were identified. Patients’ charts and chest radiographs from initial surgery to reoperation for mediastinitis were reviewed.

Results

Forty-five patients developed postoperative mediastinitis needing reoperation (0.6%). Because of loss to follow-up, 31 patients were evaluated. Eight patients (25.8%) presented fractured steel wires. Most of the broken steel wires (87.5%) manifested at the cranial site of figure-of-eight configurations. In the patients without broken steel wires, mediastinitis manifested after 14 days compared with 38 days in the patients with broken wires. Time until mediastinitis was not significantly different (P = 0.229). The mean time until steel wire disruption was 14 days (range, 4–48 days).

Conclusions

Broken steel wires were observed before mediastinitis became manifest. Fracturing occurred mainly at the cranial site of figure-of-eight configurations. The results of the present study emphasize that closure technique plays a prominent role in the development of mediastinitis. Because mediastinitis is associated with an increased risk for early morbidity, attention should be paid to patients presenting with broken steel wires. New techniques for median sternotomy closure are needed that are less prone to mechanical fatigue than are steel wires.
Evaluating the Effect of Three-Dimensional Visualization on Force Application and Performance Time during Robotics-Assisted Mitral Valve Repair
Authors: Currie Maria E. , Trejos Ana Luisa , Rayman Reiza , Chu Michael W.A. , Patel Rajni , Peters Terry , Kiaii Bob B.
Published: August 2013

Objective

The purpose of this study was to determine the effect of three-dimensional (3D) binocular, stereoscopic, and two-dimensional (2D) monocular visualization on robotics-assisted mitral valve annuloplasty versus conventional techniques in an ex vivo animal model. In addition, we sought to determine whether these effects were consistent between novices and experts in robotics-assisted cardiac surgery.

Methods

A cardiac surgery test-bed was constructed to measure forces applied during mitral valve annuloplasty. Sutures were passed through the porcine mitral valve annulus by the participants with different levels of experience in robotics-assisted surgery and tied in place using both robotics-assisted and conventional surgery techniques.

Results

The mean time for both the experts and the novices using 3D visualization was significantly less than that required using 2D vision (P < 0.001). However, there was no significant difference in the maximum force applied by the novices to the mitral valve during suturing (P = 0.7) and suture tying (P = 0.6) using either 2D or 3D visualization. The mean time required and forces applied by both the experts and the novices were significantly less using the conventional surgical technique than when using the robotic system with either 2D or 3D vision (P < 0.001).

Conclusions

Despite high-quality binocular images, both the experts and the novices applied significantly more force to the cardiac tissue during 3D robotics-assisted mitral valve annuloplasty than during conventional open mitral valve annuloplasty. This finding suggests that 3D visualization does not fully compensate for the absence of haptic feedback in robotics-assisted cardiac surgery.
Impact of Different Surgical Strategies on Perioperative Protein S100β Release in Elderly Patients Undergoing Coronary Artery Bypass Grafting
Authors: van Boven Wim Jan P. , Morariu Aurora , Salzberg Sacha P. , Gerritsen Wim B. , Waanders Frans G. , Korse Tiny C. , Aarts Leon P.
Published: August 2013

Objective

This study was designed to compare neurological injury–associated protein S100β release during three different treatment modalities, minimized closed circuit coronary artery bypass grafting (CABG) (MCABG), off-pump CABG (OPCAB), and conventional CABG (CCABG), comprising high-volume prime and cold crystalloid cardioplegia. Our working hypothesis was that fluid restriction as provided by MCABG may decrease neurological injury–associated protein S100β release.

Methods

In this prospective trial, in a tertiary center, 30 surgical patients (aged >70 years, 25 men and 5 women) undergoing first-time elective CABG were enrolled. The inclusion criteria were three-vessel disease and elective surgery. The exclusion criteria were left ventricular ejection fraction of less than 30%, use of clopidogrel, carotid disease, or needing fewer than three distal anastomoses. Protein S100β concentrations, hematocrit (Ht) levels, and PO2 levels were measured after induction of anesthesia, 10 minutes after reperfusion, upon arrival at the intensive care unit, 3 hours postoperatively at the intensive care unit, and the next morning. Statistics consisted of areas under the curve, peak levels, and correlation and variance tests.

Results

A significant negative correlation was found indicating higher S100β release at lower Ht levels and at lower PO2 levels in all study groups. The lowest S100β variance was measured during MCABG (Wilks Λ P = 0.052). The perioperative Ht was significantly higher in the MCABG group and in the OPCAB group compared with the CCABG group (P = 0.04 vs P < 0.01). At all time points, the S100β protein concentration showed no significant differences between the different surgical techniques. The mean (95% confidence interval) values of S100 area under the curve were the following: CCABG, 2.3 (1.06–3.5); MCABG, 1.44 (0.6–2.21); and OPCAB, 1.87 (1.5–2.19) [independent nonparametric Kruskal-Wallis test (P = 0.13)]. The mean (95% confidence interval) peak S100 values (calculated as the maximum value seen in a patient during the research period) were the following: CCABG, 1.07 (0.4–1.68); MCABG, 0.59 (0.28–0.90); and OPCAB, 0.83 (0.59–1.06) [independent nonparametric Kruskal-Wallis test (P = 0.22)].

Conclusions

Despite similar perioperative S100β protein release for all techniques studied, higher Ht and PO2 levels correlated with lower S100β release within all study groups. The low S100β variance during the fluid restrictive MCABG technique may be due to more efficient oxygen transport to the brain provided by significantly higher perioperative Ht levels. Further prospective data are required to better understand this complex issue.
Designing experiments to understand the variability in biochemical reaction networks
Authors: Ruess Jakob , Milias-Argeitis Andreas , Lygeros John
Published: August 2013

Exploiting the information provided by the molecular noise of a biological process has proved to be valuable in extracting knowledge about the underlying kinetic parameters and sources of variability from single-cell measurements. However, quantifying this additional informationa priori, to decide whether a single-cell experiment might be beneficial, is currently only possible in systems where either the chemical master equation is computationally tractable or a Gaussian approximation is appropriate. Here, we provide formulae for computing the information provided by measured means and variances from the first four moments and the parameter derivatives of the first two moments of the underlying process. For stochastic kinetic models for which these moments can be either computed exactly or approximated efficiently, the derived formulae can be used to approximate the information provided by single-cell distribution experiments. Based on this result, we propose an optimal experimental design framework which we employ to compare the utility of dual-reporter and perturbation experiments for quantifying the different noise sources in a simple model of gene expression. Subsequently, we compare the information content of a set of experiments which have been performed in an engineered light-switch gene expression system in yeast and show that well-chosen gene induction patterns may allow one to identify features of the system which remain hidden in unplanned experiments.
Age-dependent partnering and the HIV transmission chain: a microsimulation analysis
Authors: Bershteyn Anna , Klein Daniel J. , Eckhoff Philip A.
Published: August 2013

Efficient planning and evaluation of human immunodeficiency virus (HIV) prevention programmes requires an understanding of what sustains the epidemic, including the mechanism by which HIV transmission keeps pace with the ageing of the infected population. Recently, more detailed population models have been developed which represent the epidemic with sufficient detail to characterize the dynamics of ongoing transmission. Here, we describe the structure and parameters of such a model, called EMOD-HIV v. 0.7. We analyse the chains of transmission that allow the HIV epidemic to propagate across age groups in this model. In order to prevent the epidemic from dying out, the virus must find younger victims faster than its extant victims age and die. The individuals who enable such transmission events in EMOD-HIV v. 0.7 are higher concurrency, co-infected males aged 26–29 and females aged 23–24. Prevention programmes that target these populations could efficiently interrupt the mechanisms that allow HIV to transmit at a pace that is faster than the progress of time.
Evaluation of cytotoxicity, biophysics and biomechanics of cells treated with functionalized hybrid nanomaterials
Authors: Subbiah Ramesh , Ramasundaram Subramaniyan , Du Ping , Hyojin Kim , Sung Dongkyung , Park Kwideok , Lee Nae-Eung , Yun Kyusik , Choi Kyoung Jin
Published: August 2013

Hybrids consisting of carboxylated, single-walled carbon nanotube (c-SWNT)–silver nanoparticles (AgNPs)-DNA–poly vinyl alcohol (PVA) are synthesized via sequential functionalization to mimic the theragnostic (therapy and diagnosis) system. Carboxylation of SWNT has minimized the metal impurities with plenty of –COOH groups to produce hybrid (c-SWNT-AgNPs). The hybrid is further wrapped with DNA (hybrid-DNA) and encapsulated with PVA as hybrid composite (HC). Materials were tested against human alveolar epithelial cells (A549), mouse fibroblasts cells (NIH3T3) and human bone marrow stromal cells (HS-5). The composition-sensitive physico-chemical interactions, biophysics and biomechanics of materials-treated cells are evaluated. The cell viability was improved for HC, hybrid-PVA and c-SWNT when compared with SWNT and hybrid. SWNT and hybrid showed cell viability less than 60% at high dose (40 µg ml
−1
) and hybrid-PVA and HC retained 80% or more cell viability. The treatment of hybrid nanomaterials considerably changed cell morphology and intercellular interaction with respect to the composition of materials. Peculiarly, PVA-coated hybrid was found to minimize the growth of invadopodia of A549 cells, which is responsible for the proliferation of cancer cells. Surface roughness of cells increased after treatment with hybrid, where cytoplasmic regions specifically showed higher roughness. Nanoindentation results suggest that changes in biomechanics occurred owing to possible internalization of the hybrid. The changes in force spectra of treated cells indicated a possible greater interaction between the cells and hybrid with distinct stiffness and demonstrated the surface adherence and internalization of hybrid on or inside the cells.
Antagonism between two intestinal parasites in humans: the importance of co-infection for infection risk and recovery dynamics
Authors: Blackwell Aaron D. , Martin Melanie , Kaplan Hillard , Gurven Michael
Published: August 2013

Co-infection may affect transmission and recovery from infection, but remains an understudied element of disease ecology, particularly with regard to antagonism between parasites sharing a host. Helminth and giardia infections are often endemic in the same populations and both occupy the small intestine; yet few studies have examined interactions between these parasites. We report on helminth–giardia co-infections in a panel study of forager–horticulturalists in the Bolivian lowlands. Parasites were identified in faecal samples from 3275 participants, collected during 5235 medical exams over 6 years. Longitudinal co-infection patterns were examined using logistic mixed and multi-state Markov models. The most prevalent infections were hookworm (56%),
Giardia lamblia
(30%) and
Ascaris lumbricoides
(15%). Cross-sectionally, hookworm and
A. lumbricoides
were negatively associated with
G. lamblia
(OR = 0.60; OR = 0.65, respectively). Longitudinally, giardia infection was less likely in helminth-infected individuals (HR: 0.46). Infection with helminths was also less likely for individuals infected with giardia (HR: 0.71). Finally, treatment with mebendazole reduced subsequent hookworm infections, but resulted in a marginal increase in the odds of
G. lamblia
infection. Our results provide evidence for an antagonistic relationship between helminths and giardia, and suggest that co-infection should be considered in disease transmission models and treatment decisions.
Phylogenomics demonstrates that breviate flagellates are related to opisthokonts and apusomonads
Authors: Brown Matthew W. , Sharpe Susan C. , Silberman Jeffrey D. , Heiss Aaron A. , Lang B. Franz , Simpson Alastair G. B. , Roger Andrew J.
Published: August 2013

Most eukaryotic lineages belong to one of a few major groups. However, several protistan lineages have not yet been robustly placed in any of these groups. Both the breviates and apusomonads are two such lineages that appear to be related to the Amoebozoa and Opisthokonta (i.e. the ‘unikonts’ or Amorphea); however, their precise phylogenetic positions remain unclear. Here, we describe a novel microaerophilic breviate,Pygsuia biformagen. nov. sp. nov., isolated from a hypoxic estuarine sediment. Ultrastructurally, this species resembles the breviate generaBreviataandSubulatomonasbut has two cell morphologies, adherent and swimming. Phylogenetic analyses of the small sub-unit rRNA gene show thatPygsuiais the sister to the other breviates. We constructed a 159-protein supermatrix, including orthologues identified in RNA-seq data fromPygsuia. Phylogenomic analyses of this dataset show that breviates, apusomonads and Opisthokonta form a strongly supported major eukaryotic grouping we name the Obazoa. Although some phylogenetic methods disagree, the balance of evidence suggests that the breviate lineage forms the deepest branch within Obazoa. We also found transcripts encoding a nearly complete integrin adhesome fromPygsuia, indicating that this protein complex involved in metazoan multicellularity may have evolved earlier in eukaryote evolution than previously thought.
A problem is a problem is a benefit? Generation Y perceptions of open‐plan offices
Authors: Rasila Heidi , Rothe Peggie
Published: August 2013

Purpose

The purpose of this paper is to understand how the youngest generation at work perceives problems that are linked to open‐plan offices. They are the future users of the work environments and thus it is important to understand how they perceive different office solutions. The paper looks at one specific type of job and one group of office employees: generation Y – those born in the 1980s and early 1990s – working in a contact centre environment.

Design/methodology/approach

The research was carried out as a case study. In total, 20 thematic interviews were conducted among the representatives of generation Y from three different sites of one big Finnish telecommunications company. The themes of the interviews were outlined by a thorough literature review concerning problems that are often linked to open office solutions.

Findings

The findings suggest that in this case, the generation Y employees in fact liked their open‐plan office. They acknowledged most of the issues or “problems” that the literature suggests, but they did not necessarily see these purely in a negative way. Instead, they often perceived these issues as fair trade‐offs for some greater good. This result supports the idea that open‐plan offices are complex and interrelated systems where all parts affect the others.

Research limitation/implications

The main limitation of this research is the small sample size. The results cannot be generalized to all young office employees; rather, they are intended to give a first in‐depth insight into the experiences of one specific group of users in the complex interrelated open‐plan office system.

Originality/value

The paper's findings add to the understanding about how generation Y perceives their work environment. The research also highlights a limitation in earlier open‐plan offices and suggests that future research needs to take a broader perspective on this complex system.
An agent based model for the subsidized LPG with a closed distribution system
Authors: Cahyaningrum Asri , M. Simatupang Togar
Published: August 2013

Purpose

– This paper aims to explore major causes of the failure of the existing subsidized liquefied petroleum gas (LPG) distribution system and recommends alternative strategies.

Design/methodology/approach

– The analysis of subsidized LPG with a closed distribution system was carried out based on preliminary study, secondary data collection, and in-depth interviews to identify the root causes of the failure in achieving the desired service levels. In this research, agent based modeling and simulation was used to explain the phenomena occurred in the closed distribution system represented by three types of agents, namely selling agents, sub-selling agents, and end-users.

Findings

– Agent based modeling and simulation was successfully applied to describe the undesired symptoms in the closed distribution system. The simulation shows that the distribution system provides a service level of 81.61 percent by selling agents and 97.38 percent by sub-selling agents. The root cause analysis indicates that service and inventory levels in the LPG distribution system are strongly influenced by end-users demand variations, rationing system, and the occurrence of inventory leakage. To enhance the system quality, the Indonesian Government needs to implement the LPG with a closed distribution system using control card in real practice so that monitoring system can be significantly improved and ensure well-targeted subsidy.

Research limitations/implications

– This research is limited to the discussion of inventory level and availability. It does not include the issue of pricing, speculation, and targeting accuracy, because of the limitation of the existing data.

Practical implications

– This research will assist stakeholders involved in the distribution system such as selling agents and retailers to better understand the true potential of the LPG closed distribution system in preventing shortages.

Originality/value

– This paper describes that agent based modeling and simulation is very useful, especially to gain insights for improving the LPG closed distribution system.
Relations with stakeholders in Turkey: the sample of ISE‐50 Index
Authors: Cüneyt Arslantaş Cem , Afacan Fındıklı Mine
Published: August 2013

Purpose

The purpose of this paper is twofold: to examine to what extent the companies could adapt the corporate governance principles of the Capital Markets Board (CMB) to their own structures in terms of stakeholder relations; and second, to raise awareness of the deficiencies related to these relations.

Design/methodology/approach

The companies listed in ISE‐50 Index in the fourth quarter of 2010 were examined. The corporate governance principles compliance reports, activity reports and articles of associations of the companies that should be issued were examined to obtain the data. The research findings have been studied under five subtitles: company policies relating to stakeholders; promoting the participation of stakeholders in the management; human resources policies; relations with the customers and suppliers; ethical rules and social responsibility.

Findings

It is found that the companies have not taken any action for the representation of the employees in the board of directors. Also, it is seen that most of the companies, when any interest group is privileged, do not make the confidential business information obtained due to such privilege used so as to violate the equal opportunity principle. There are difficulties in paying attention to the confidentiality of the confidential business information related to the customers and suppliers.

Practical implications

The findings of this study can indicate that, effective handling of applications reflecting the perception related with the stakeholders of the corporate governance could only be probable if CMB corporate governance principles “practice and specify what you do not practice” have become compulsory.

Originality/value

The paper provides useful information on the relationships of the companies listed in the ISE‐50 Index with stakeholders.
Re‐examining and empirically validating the End User Computing Satisfaction models for satisfaction measurement in the internet banking context
Authors: Marakarkandy Bijith , Yajnik Nilay
Published: August 2013

Purpose

The main focus of the study was to validate the End User Computing Satisfaction (EUCS) model in the context of internet banking and to determine the major factors which contribute to level of satisfaction of internet banking users in India.

Design/methodology/approach

A survey questionnaire was administered on internet banking users and a total of 387 responses were collected. A factor analysis on the 12 items used in the EUCS model with oblique (non‐orthogonal) rotation and five fixed factors revealed the existence of the same latent constructs hypothesized in the original EUCS model. Confirmatory Factor Analysis (CFA) was then used to test and validate the four hypothesized models for model fit.

Findings

The current study confirms the evidence found in extant literature that EUCS is a second‐order construct. In this study the factor “Format” was found to have the highest loading and the factor “Content” had the lowest factor loading among all the five latent constructs in the EUCS model for internet banking. The factor “Accuracy” had the highest mean score and the factor “Content” had the lowest mean scores indicating that bank customers were satisfied with the accuracy of the information on the banks web site but were not comparatively satisfied by the information content on the web site.

Research limitations/implications

This study was done based on a call by Pikkarainen et al. (2006) to validate the EUCS instrument for internet banking satisfaction in different countries to enhance the generalizability of the findings. This research is limited to samples from India and results of other countries need to be considered before a generalization of the findings can be made. This study will be useful to policy makers and banks to devise strategies for increasing the use of internet banking.

Originality value

There is a myriad of literature on factors which lead to adoption of internet banking but extant literature on internet banking user satisfaction is limited particularly pertaining to banks operating in India. This study attempts to fill this gap in the literature.
A comparative study on static properties of a three‐main‐truss and three‐cable‐plane cable‐stayed bridge
Authors: Zheng Pengfei , Dai Gonglian
Published: August 2013

Purpose

This paper aims to obtain the further and overall generation about the static characteristics of the structure for the better application of the structure.

Design/methodology/approach

Through nonlinear finite element simulation, serials of comparative analyses are performed on this structure and other three assumed structures, which illustrate the effect of the main part of the structure on the structural static properties. Meanwhile, adopting the first order method, spatial cable force optimization makes the structural mechanic more rational.

Findings

Under same level stress, this three‐main‐truss and three‐cable‐plane bridge could save almost 38.8 percent vertical chords materials consumption at least. In contrast, this bridge has a lower lateral torsional stiffness, considering the key to raise the lateral and torsional stiffness is enhancing axial stiffness of plane bracing, the suitable plane bracing members area is twice as the original area. After rational optimization, the cable tension ratio between the mid‐cable plane and the two side‐cable planes ranges from 1.09 to 1.14.

Originality/value

The work in this paper of the comparative analysis could give other engineers a way to a deep analysis method for the structural analysis, especially in civil engineering. The conclusions would provide other designers some applied advice.
Pauline Arnold (1894‐1974): pioneer in market research
Authors: Brian Jones D.G.
Published: August 2013

Purpose

The purpose of this paper is to provide a biographical sketch of Pauline Arnold focusing on her pioneering contributions to the field of market research.

Design/methodology/approach

Archival source material included the Pauline Arnold Collection at the University of Minnesota and the Lucy Sallick Papers including correspondence, unpublished documents, and the transcript of a 1995 oral history interview with Matilda White Riley, who was Pauline Arnold's stepdaughter. Primary historical source material includes the scholarship, both published and unpublished, of the subject. An important primary, published source for this study is the periodical, Market Research, to which Arnold contributed under the auspices of the Market Research Corporation of America from 1934 through to 1938.

Findings

Pauline Arnold's contributions to the field of market research are documented.

Originality/value

Pauline Arnold has been cited as having made important but neglected contributions to market research, including her advocating an understanding of customers' motives, needs, and wants. However, there is no published account of Arnold's life and work.
Lillian Gilbreth's psychologically enriched scientific management of women consumers
Authors: Graham Laurel D.
Published: August 2013

Purpose

Lillian Moller Gilbreth (1878‐1972) extended scientific management into marketing practice in the late 1920s. This paper aims to illuminate several of these practical extensions.

Design/methodology/approach

The paper is an historical case study.

Findings

Gilbreth brought her psychologically enlightened brand of scientific management to Macy's Department Store in New York City in the mid‐1920s; she accomplished early marketing research for Johnson & Johnson in 1926; and she designed model kitchens in the late 1920s and 1930s which showed homemakers how to minimize wasted motion and unnecessary fatigue in housework while maximizing the psychological well‐being of their families.

Practical implications

Gilbreth's accomplishments show that marketing research has a longer history than was once assumed, offering further support for the revision of Keith's 1960 periodization of this history.

Originality/value

This paper is the first to reveal how Gilbreth's unique mix of psychology and scientific management entered the field of marketing in the interwar period.
Beyond “caste‐typing”?
Authors: Foster Davis Judy
Published: August 2013

Purpose

The purpose of this paper is to present a biographical review of the career of the late Caroline Robinson Jones (1942‐2001) in order to understand her challenges and contributions to the advertising profession. Prior to her death, she was considered the foremost African‐American woman in the advertising business. She was the first black woman to serve as a vice president of a major mainstream advertising agency and also established a respected agency bearing her own name. This paper focuses on Jones' contributions to marketing practice and her experiences as a woman of color in the advertising industry.

Design/methodology/approach

This paper uses a traditional historical narrative approach largely based on archival materials housed in the Caroline Jones Collection at the Archives Center of the National Museum of American History at the Smithsonian Institution. Relevant secondary literature was also employed to provide appropriate context.

Findings

While the advertising industry has historically been noted for its lack of diversity among its professional ranks, Jones made significant contributions to the industry. Yet, despite her trailblazing accomplishments, findings suggest her efforts were constrained by structural oppression in the industry concerning gender and race.

Originality/value

Scholarly literature reflecting the contributions and experiences of women of color in the advertising business is nearly non‐existent. This paper provides an analysis using sources which are valuable in understanding career opportunities and challenges for women of color in advertising professions.