bluuebunny/crossref_metadata_2025 huggingface dataset:
Heterodyne interference lithography for one-step micro/nano multiscale structuring
Authors: Kang Bongchul , Noh Jiwhan , Lee Joohyung , Yang Minyang
Published: December 2013

A heterodyne interference lithography method using two slightly different wavelengths for one-step multi-scale fabrication of micro/nano hybrid structures is presented. This method has been used to locally fabricate one- and two-dimensional periodical sub-wavelength nanopatterns with a spatial periodicity of several micrometers. Furthermore, multilayered nanostructures with different layer compositions were fabricated by simply controlling the intensity ratio of the two wavelengths. As a result, this method can cost-effectively maximize the degree of freedom of the interference lithography method. The heterodyne interference lithography method can potentially be used in the fabrication of unconventional bio-mimetically engineered surfaces as well as heterocomplexed optics.
Extreme ultra-violet movie camera for imaging microsecond time scale magnetic reconnection
Authors: Chai Kil-Byoung , Bellan Paul M.
Published: December 2013

An ultra-fast extreme ultra-violet (EUV) movie camera has been developed for imaging magnetic reconnection in the Caltech spheromak/astrophysical jet experiment. The camera consists of a broadband Mo:Si multilayer mirror, a fast decaying YAG:Ce scintillator, a visible light block, and a high-speed visible light CCD camera. The camera can capture EUV images as fast as 3.3 × 106 frames per second with 0.5 cm spatial resolution. The spectral range is from 20 eV to 60 eV. EUV images reveal strong, transient, highly localized bursts of EUV radiation when magnetic reconnection occurs.
Compact drain-current model for undoped cylindrical surrounding-gate metal-oxide-semiconductor field effect transistors including short channel effects
Authors: Smaani Billel , Latreche Saida , Iñiguez Benjamín
Published: December 2013

In this paper, we present a compact model for undoped short-channel cylindrical surrounding-gate MOSFETs. The drain-current model is expressed as a function of the mobile charge density, which is calculated using the analytical expressions of the surface potential and the difference between surface and center potentials model. The short-channel effects are well incorporated in the drain-current model, such as the drain-induced barrier lowering, the charge sharing effect (VT Roll-off), the subthreshold slope degradation, and the channel length modulation. A comparison of the model results with 3D numerical simulations using Silvaco Atlas-TCAD presents a good agreement from subthreshold to strong inversion regime and for different bias voltages.
Self-limiting lithiation of electrode nanoparticles in Li-ion batteries
Authors: Drozdov A. D. , Sommer-Larsen P. , deClaville Christiansen J.
Published: December 2013

A model is derived for the viscoplastic behavior of a host medium driven by stress-induced diffusion of guest atoms. The constitutive equations are applied to study development of stresses in a spherical electrode particle subjected to insertion of lithium. Numerical simulation demonstrates the ability of the model to capture basic phenomena observed in anode nanoparticles under lithiation: formation of a sharp interphase between a Li-poor core and a Li-rich shell, slowing down of the interphase motion revealed as self-limiting lithiation, and growth of tensile hoop stresses near the outer surface of a particle leading to its fracture.
Exciton-blocking phosphonic acid-treated anode buffer layers for organic photovoltaics
Authors: Zimmerman Jeramy D. , Song Byeongseop , Griffith Olga , Forrest Stephen R.
Published: December 2013

We demonstrate significant improvements in power conversion efficiency of bilayer organic photovoltaics by replacing the exciton-quenching MoO3 anode buffer layer with an exciton-blocking benzylphosphonic acid (BPA)-treated MoO3 or NiO layer. We show that the phosphonic acid treatment creates buffers that block up to 70% of excitons without sacrificing the hole extraction efficiency. Compared to untreated MoO3 anode buffers, BPA-treated NiO buffers exhibit a ∼ 25% increase in the near-infrared spectral response in diphenylanilo functionalized squaraine (DPSQ)/C60-based bilayer devices, increasing the power conversion efficiency under 1 sun AM1.5G simulated solar illumination from 4.8 ± 0.2% to 5.4 ± 0.3%. The efficiency can be further increased to 5.9 ± 0.3% by incorporating a highly conductive exciton blocking bathophenanthroline (BPhen):C60 cathode buffer. We find similar increases in efficiency in two other small-molecule photovoltaic systems, indicating the generality of the phosphonic acid-treated buffer approach to enhance exciton blocking.
A silicon-wafer based p-n junction solar cell by aluminum-induced recrystallization and doping
Authors: Gardelis S. , Nassiopoulou A. G. , Manousiadis P. , Vouroutzis Ν. , Frangis N.
Published: December 2013

We fabricated a silicon-wafer based p-n junction solar cell with conversion efficiency of 11% without conventional doping of the emitter or the use of anti-reflecting coatings. The emitter was originally nanocrystalline, grown on n-type crystalline Si and covered with a thin semi-transparent Al layer. Annealing in nitrogen at 430 °C promoted a simultaneous aluminum (Al)-induced recrystallization and Al-doping of the emitter. The recrystallized emitter consisted of considerably larger Si grains which were epitaxially crystallized on the Si substrate. These two effects led to a considerable improvement of the electrical and photovoltaic properties of the resulting p-n junction.
Acoustic emission and changes in dislocation structure and magnetostriction accompanying plastic deformation of [126]-oriented Fe-Ga alloy single crystals
Authors: Saha B. , Ramanathan M. , Ren C. , Appusamy K. , McCarter M. K. , Guruswamy S. , Cook R. , Miller D. J.
Published: December 2013

Controlled compressive deformation of [126]-oriented Fe-20 at. % Ga alloy single crystal along [126] direction results in large and asymmetric changes in the magnetostriction of the sample. This is in contrast to a much smaller change in magnetostriction observed in [100]-oriented single crystal deformed along [001] direction. Deformation of [126]-oriented crystal along [126] direction involved operation of only one of the slip systems. This is confirmed by TEM examination that showed only a single set of dislocation array which introduces asymmetric strain modulation in the crystal. The [100]-oriented crystal deformation involved operation of multiple slip systems and formation of several sets of dislocation arrays which introduce more symmetric strain modulations. The results suggest that the nature of strain modulation introduced by the dislocation arrays has a strong influence on the magnetostrictive behavior. Several sudden load drops accompanied by acoustic emissions and formation of slip bands were observed during [126]-oriented crystal deformation, while no such load drops or audible acoustic emissions were seen during the [001]-oriented crystal deformation.
Indium tin oxide and indium phosphide heterojunction nanowire array solar cells
Authors: Yoshimura Masatoshi , Nakai Eiji , Tomioka Katsuhiro , Fukui Takashi
Published: December 2013

Heterojunction solar cells were formed with a position-controlled InP nanowire array sputtered with indium tin oxide (ITO). The ITO not only acted as a transparent electrode but also as forming a photovoltaic junction. The devices exhibited an open-circuit voltage of 0.436 V, short-circuit current of 24.8 mA/cm2, and fill factor of 0.682, giving a power conversion efficiency of 7.37% under AM1.5 G illumination. The internal quantum efficiency of the device was higher than that of the world-record InP cell in the short wavelength range.
Control of the polarity of magnetization vortex by torsion
Authors: Wang Jie , Li Gui-Ping , Shimada Takahiro , Fang Hui , Kitamura Takayuki
Published: December 2013

The switching behavior of vortex polarity in a circular ferromagnetic nanodot subjected to torsion is investigated by using a real space phase field model, which explicitly includes the coupling between magnetization and mechanical strain. It is found that the vortex polarity of the nanodot can be switched by torsion when the sign of the torsion is opposite to that of vortex chirality whereas switching does not take place if the sign of torsion is the same as that of vortex chirality. The magneto-elastic coupling and demagnetization field play a decisive role in the polarity switching, which involves an intriguing interplay of magnetization, strain, and demagnetization. The results suggest another way to control vortex polarity by mechanical torsion other than magnetic field and electric current.
Long-term, intermittent testing of sandwich polymer light-emitting electrochemical cells
Authors: Li Xiaoyu , AlTal Faleh , Liu Guojun , Gao Jun
Published: December 2013

The long-term luminance decay of sandwich polymer light-emitting electrochemical cells has been investigated. The cells have been operated multiple times over a period of four months, all under a constant current density of 167 mA/cm2. In-between the constant-current runs, the cells were stored at room temperature for up to two months. We identify several factors that affect the luminance and its decay. The peak luminance reached during the virgin runs decreases if the cells are stored after the deposition of the top electrode. During operation, the luminance also decreases after reaching a peak value. However, extended storage at room temperature leads to the recovery of the peak luminance. The luminance recovery can be attributed to the relaxation of doping which reverses the effect of luminescence quenching. A long term, irreversible luminance decay is also observed and attributed to the formation of non-emitting, non-conductive black spots which leads to the loss of emitting area and an increased effective current density. The results illustrate the importance both On and Off states in characterizing the stability of polymer LECs.
Temperature dependence of diffusion length, lifetime and minority electron mobility in GaInP
Authors: Schultes F. J. , Christian T. , Jones-Albertus R. , Pickett E. , Alberi K. , Fluegel B. , Liu T. , Misra P. , Sukiasyan A. , Yuen H. , Haegel N. M.
Published: December 2013

The mobility of electrons in double heterostructures of p-type Ga0.50In0.50P has been determined by measuring minority carrier diffusion length and lifetime. The minority electron mobility increases monotonically from 300 K to 5 K, limited primarily by optical phonon and alloy scattering. Comparison to majority electron mobility over the same temperature range in comparably doped samples shows a significant reduction in ionized impurity scattering at lower temperatures, due to differences in interaction of repulsive versus attractive carriers with ionized dopant sites. These results should be useful in modeling and optimization for multi-junction solar cells and other optoelectronic devices.
The impact of nanoperforation on persistent photoconductivity and optical quenching effects in suspended GaN nanomembranes
Authors: Volciuc Olesea , Braniste Tudor , Tiginyanu Ion , Stevens-Kalceff Marion A. , Ebeling Jakob , Aschenbrenner Timo , Hommel Detlef , Ursaki Veaceslav , Gutowski Jürgen
Published: December 2013

We report on fabrication of suspended ∼15 nm thick GaN membranes nanoperforated in an ordered fashion using direct writing of negative charges by focused ion beam and subsequent photoelectrochemical etching of GaN epilayers. Both continuous and nanoperforated membranes exhibit persistent photoconductivity (PPC), which can be optically quenched under excitation by 546 nm radiation. Optical quenching of PPC occurs also under relatively intense intrinsic excitation of nanoperforated membranes by 355 nm radiation at T < 100 K. The proposed explanation is based on strong surface localization of charge carriers in nanoperforated membranes and UV-induced reactions occurring at surface states under intense intrinsic excitation.
Electron kinetics in a microdischarge in nitrogen at atmospheric pressure
Authors: Levko Dmitry
Published: December 2013

Electron kinetics during a microdischarge in nitrogen at atmospheric pressure is studied using the one-dimensional Particle-in-Cell/Monte Carlo Collisions model. It is obtained that the electron energy distribution function can be divided into three parts, namely, the non-equilibrium low-energy part, the Maxwellian function at moderate energies, and the high-energy tail. Simulation results showed that the role of the high-energy tail of electron energy distribution increases, when the distance between electrodes increases.
Fifteen microsatellite loci for use in non-invasive sampling studies of the antilopine wallaroo (Macropus antilopinus)
Authors: Wadley Jessica J. , Austin Jeremy J. , Gardner Michael G. , Fordham Damien A.
Published: December 2013

A set of 15 microsatellite loci was optimised for multilocus genotyping of non-invasively collected samples of Macropus antilopinus (antilopine wallaroo). Primers were combined in three PCR multiplexes in order to increase the quality of genotypes from scat samples and to allow for replication. In a screen of 104 scat samples from two populations in north-eastern Australia, three loci were found to be monomorphic while the remaining 12 loci had 2–10 alleles. Genotype frequencies for all 12 microsatellite loci from the two populations did not differ significantly from Hardy–Weinberg equilibrium, and there was no evidence of linkage disequilibrium. These informative markers are specifically designed for non-invasive samples and will be used to assess population structure and conservation genetics of this species in the future.
Compliance with Postexposure Screening and Treatment of Latent Tuberculosis Infection among Healthcare Workers in a Tertiary Care Hospital in Saudi Arabia
Authors: Balkhy Hanan H. , Miller Thaddeus L. , Ali Saira , Nuzzo Jennifer B. , Kentenyants Karine , El-Saed Aiman , McNabb Scott J. N.
Published: December 2013

Background.

Controlling tuberculosis (TB) infection among occupationally exposed healthcare workers (HCWs) may be challenging.

Methods.

We retrospectively reviewed clinical records of HCWs who were exposed to patients diagnosed with infectious TB at King Abdulaziz Medical City, Riyadh, Saudi Arabia, between 2008 and 2010. The collected data included baseline tuberculin skin test (TST) status, potential predictors of TST positivity, postexposure diagnosis of latent TB infection (LTBI), and postexposure compliance with LTBI therapy.

Results.

Thirteen patients were diagnosed with infectious pulmonary TB during the study period. A total of 298 HCWs met our definition for exposure. Exposed HCWs tended to be female (62.9%), non-Saudi (83.9%), nurses (68.6%), or respiratory therapists (24.0%) working in critical care locations (72.8%). Baseline (preemployment) TST documentation existed for 41.3% (123/298). Among those with documented baseline TSTs, 51.2% (63/123) were positive, representing 21.1% (63/298) of all HCWs. Only 48.9% (115/235) of exposed HCWs who had negative or unknown preexposure TST status had their TST tested after exposure. Approximately 46.1% (53/115) of them were diagnosed with postexposure LTBI, and 92.5% (49/53) of them were prescribed LTBI therapy. Among those, 93.9% (46/49) started LTBI therapy; however, 82.6% (38/46) failed to complete the recommended course.

Conclusions.

We found low rates of baseline TST documentation and postexposure screening among exposed HCWs. Compliance with initiating postexposure isoniazid prophylaxis among HCWs was fair, but only a small fraction of those who started prophylaxis completed the recommended course of therapy. These findings suggest substantial opportunities to implement administrative measures to enhance LTBI management among HCWs.
TDP1 deficiency sensitizes human cells to base damage via distinct topoisomerase I and PARP mechanisms with potential applications for cancer therapy
Authors: Alagoz Meryem , Wells Owen S. , El-Khamisy Sherif F.
Published: December 2013

Base damage and topoisomerase I (Top1)-linked DNA breaks are abundant forms of endogenous DNA breakage, contributing to hereditary ataxia and underlying the cytotoxicity of a wide range of anti-cancer agents. Despite their frequency, the overlapping mechanisms that repair these forms of DNA breakage are largely unknown. Here, we report that depletion of Tyrosyl DNA phosphodiesterase 1 (TDP1) sensitizes human cells to alkylation damage and the additional depletion of apurinic/apyrimidinic endonuclease I (APE1) confers hypersensitivity above that observed for TDP1 or APE1 depletion alone. Quantification of DNA breaks and clonogenic survival assays confirm a role for TDP1 in response to base damage, independently of APE1. The hypersensitivity to alkylation damage is partly restored by depletion of Top1, illustrating that alkylating agents can trigger cytotoxic Top1-breaks. Although inhibition of PARP activity does not sensitize TDP1-deficient cells to Top1 poisons, it confers increased sensitivity to alkylation damage, highlighting partially overlapping roles for PARP and TDP1 in response to genotoxic challenge. Finally, we demonstrate that cancer cells in which TDP1 is inherently deficient are hypersensitive to alkylation damage and that TDP1 depletion sensitizes glioblastoma-resistant cancer cells to the alkylating agent temozolomide.
Expression and promoter characterization of BbPacC, a pH response transcription factor gene of the entomopathogenic fungus Beauveria bassiana
Authors: Zhou Yong-Hong , Hou Lei , Zhang Yong-Jun , Fan Yan-Hua , Luo Zhi-Bing , Jin Dan , Zhou Qiao-Sheng , Li Yu-Jie , Wang You , Pei Yan
Published: December 2013

To survive, the entomopathogenic fungus Beauveria bassiana, which shows promise as a biocontrol agent for a variety of pests, including agricultural and forestry pests and vectors of human pathogens, must tailor gene expression to the particular pH of its environment. The pH response transcription factor gene BbPacC and its flanking sequence were cloned from this fungus. Quantitative reverse transcription (RT)-PCR revealed that it is highly induced by alkaline pH and salt stress, and the expression level achieved twice that of the housekeeping gene γ-actin. A microfluorometric assay indicated that the 1479 bp promoter region could activate the expression of enhanced green fluorescent protein (EGFP) under the same conditions. Truncation analysis showed that the 1479, 1274, 1040, 888 and 742 bp promoters have similar efficiencies in activating expression of β-glucuronidase (GUS). The GUS activities of corresponding transformants reached approximately 50 % that of those containing the strong constitutive promoter PtrpC. A truncation upstream at the –572 bp position (referenced to the translation start codon ATG), however, resulted in a significant loss of GUS activity. Both the upstream absences of the −502 and −387 bp positions caused almost complete loss of GUS activity. These results suggest that PPacC is an efficient, alkaline, and salt-inducible promoter, the core cis-elements are mainly located within the –742 to –502 bp region, and promoters equal to or longer than 742 bp may be feasible for regulating gene expression in response to an ambient pH or salt stress.
Extensive Phenotypic Changes Associated with Large-scale Horizontal Gene Transfer
Authors: Dougherty Kevin , Smith Brian A. , Moore Autumn F. , Maitland Shannon , Fanger Chris , Murillo Rachel , Baltrus David A.
Published: December 2013

Horizontal gene transfer often leads to phenotypic changes within recipient organisms independent of any immediate evolutionary benefits. While secondary phenotypic effects of horizontal transfer (i.e. changes in growth rates) have been demonstrated and studied across a variety of systems using relatively small plasmid and phage, little is known about how size of the acquired region affects the magnitude or number of such costs. Here we describe an amazing breadth of phenotypic changes which occur after a large-scale horizontal transfer event (~1Mb megaplasmid) withinPseudomonas stutzeriincluding sensitization to various stresses as well as changes in bacterial behavior. These results highlight the power of horizontal transfer to shift pleiotropic relationships and cellular networks within bacterial genomes. They also provide an important context for how secondary effects of transfer can bias evolutionary trajectories and interactions between species. Lastly, these results and system provide a foundation to investigate evolutionary consequences in real time as newly acquired regions are ameliorated and integrated into new genomic contexts.
Suicidal Carbon Monoxide Poisoning by Combining Formic Acid and Sulfuric Acid Within a Confined Space
Authors: Lin Peter T. , Dunn William A.
Published: December 2013

Suicide by inhalation of carbon monoxide produced by mixing formic acid and sulfuric acid within a confined space is a rare method of suicide. This method is similar to the so‐called “detergent suicide” method where an acid‐based detergent is mixed with a sulfur source to produce hydrogen sulfide. Both methods produce a toxic gas that poses significant hazards for death investigators, first responders and bystanders. Carbon monoxide is an odorless gas, while hydrogen sulfide has a characteristic rotten eggs odor, so the risks associated with carbon monoxide are potentially greater due to lack of an important warning signal. While detergent suicides have become increasingly common in the USA, suicide with formic acid and sulfuric acid is rare with only three prior cases being reported. Greater awareness of this method among death investigators is warranted because of the special risks of accidental intoxication by toxic gas and the possibility that this method of suicide will become more common in the future.
Pneumomediastinum and Soft Tissue Emphysema in Pediatric Hanging
Authors: Sieswerda‐Hoogendoorn Tessa , Strik Anne S. , Hilgersom Nick F. J. , Soerdjbalie‐Maikoe Vidija , van Rijn Rick R.
Published: December 2013

Postmortem computed tomography (CT) is increasingly being used as a tool in forensic pathology. The exact value of postmortem imaging in detecting specific conditions has not yet been established, but in specific cases, it can be used as a diagnostic tool demonstrating findings that remain undetected during autopsy, as in this case. Pneumomediastinum and soft tissue emphysema were detected with postmortem CT in a 3‐year‐old girl after hanging. It was not found during autopsy. This radiological finding matches 3 adult cases previously described. It is assumed that in this case, the first reported in a child, hanging was the most likely cause as well. In the adult cases, it was interpreted as a vital sign; the person must have been alive to create a pressure gradient causing rupture of the alveoli. This case demonstrates one of the added values of postmortem imaging, the possibility of demonstrating findings that remain undetected during autopsy.
The importance of native trees for forest bird conservation in tropical farmland
Authors: Douglas D. J. T. , Nalwanga D. , Katebaka R. , Atkinson P. W. , Pomeroy D. E. , Nkuutu D. , Vickery J. A.
Published: December 2013

Trees in farmland provide valuable ecosystem services that enhance agricultural productivity and income, as well as supporting biodiversity such as birds. A better understanding of the benefits of farmland trees for birds, specifically the relative value of native and exotic trees, is essential in developing effective management options, particularly within tropical regions with intense cultivation pressure. In farmland in central Uganda, neither total bird species richness nor richness of forest visitors (non‐forest dependent) were related to any measures of tree cover, whereas richness of forest‐dependent bird species showed a positive relationship with the number of native tree species. The density of 10 out of 17 forest‐dependent bird species within farmland showed at least one significant relationship with measures of tree cover; variables relating to native trees typically had more, and stronger, positive effects on bird density than exotic trees. The combined density of 17 forest‐dependent bird species on farmland was positively related to both the total number of native trees and number of large native trees. Increasing the density of forest‐dependent bird species by 1 bird ha−1 within a farmland site is predicted to require c. one to two large native trees, or c. 30 native trees of all sizes, per ha. Despite comprising c. 40% of all trees, exotics exerted little positive influence on forest birds, possibly because these offer poorer resources in terms of foraging, nesting and shelter. While numerous previous studies in the tropics have considered the value, for birds, of tree cover in farmland, few have focused on tree size or species composition. This study suggests that the retention or planting of native trees is an important tool for conserving forest birds within farmland, will provide additional ecosystem services, and should be encouraged through, for example, agricultural development schemes, extension advice and demonstration farms.
Effects of astaxanthin‐enriched yeast on mucosal IgA induction in the jejunum and ileum of weanling mice
Authors: Nagayama Tatsuhiko , Sugimoto Miki , Ikeda Shuntaro , Kume Shinichi
Published: December 2013

The present study was conducted to clarify the effects of astaxanthin‐enriched yeast on the concentration of immunoglobulin A (IgA), the numbers of IgA antibody‐secreting cells (ASC) and the messenger RNA (mRNA) expression of IgA C‐region in the jejunum and ileum of weanling mice. Weanling mice were fed rodent feed or astaxanthin‐enriched yeast‐supplemented rodent feed for 7, 14 or 21 days. Supplemental astaxanthin‐enriched yeast increased the numbers of IgA ASC in the jejunum and ileum after 7, 14 and 21 days of treatment. Supplemental astaxanthin‐enriched yeast increased IgA concentrations in the jejunum after 21 days of treatment, but IgA concentrations in the ileum were not affected by the treatment. The mRNA expressions of IgA C‐region in the jejunum after 14 and 21 days of treatment and the ileum after 14 days of treatment were enhanced by supplementation of astaxanthin‐enriched yeast. These results indicate that supplementation of astaxanthin‐enriched yeast is effective to enhance the numbers of IgA ASC in the jejunum and ileum and IgA concentrations in the ileum of weanling mice.
Effects of hypothalamic dopamine (DA) on salsolinol (SAL)‐induced prolactin (PRL) secretion in male goats
Authors: Jin Jin , Hara Sayaka , Sawai Ken , Fülöp Ferenc , Nagy György Miklos , Hashizume Tsutomu
Published: December 2013

The aim of the present study was to clarify the effects of hypothalamic dopamine (DA) on salsolinol (SAL)‐induced prolactin (PRL) release in goats. ThePRL‐releasing response to an intravenous (i.v.) injection ofSALwas examined after treatment with augmentation of centralDAusing carbidopa (carbi) andL‐dopa in male goats under 8‐h (8 h light, 16 h dark) or 16‐h (16 h light, 8 h dark) photoperiod conditions. The carbi andL‐dopa treatments reduced basalPRLconcentrations in the 16‐h photoperiod group (P < 0.05), while a reduction was not observed in the 8‐h photoperiod group. The mean basal plasmaPRLconcentration in the control group for the 8‐h photoperiod was lower than that for the 16‐h photoperiod (P < 0.05).SALsignificantly stimulated the release ofPRLpromptly after the injection in both the 8‐ and 16‐h photoperiod groups (P < 0.05).PRL‐releasing responses for the 16‐h photoperiod were greater than those for the 8‐h photoperiod (P < 0.05). The carbi andL‐dopa treatments bluntedSAL‐inducedPRLrelease in both the 8‐ and 16‐h photoperiods (P < 0.05). These results indicate that hypothalamicDAblunts theSAL‐induced release ofPRLin male goats, regardless of the photoperiod, which suggests that bothSALandDAare involved in regulating the secretion ofPRLin goats.
Medical Biostatistics, 3rd Edition by INDRAYAN, ABHAYA
Authors: Park Mira
Published: December 2013

EDITOR: TAESUNG PARK

Medical Biostatistics, 3rd Edition

(Abhaya Indrayan)

Mira Park

Introduction to Linear Regression Analysis (5th Ed.)

(Douglas C. Montgomery, Elizabeth A. Peck, and G. Geoffrey Vining)

Hee-Seok Oh

Statistical Methods with Applications to Demography and Life Insurance

(Estate V. Khmaladze)

Dong Wan Shin

Categorical Data Analysis, 3rd Edition

(Alan Agresti)

Donguk Kim
Mechanism of cytotoxic action of crambescidin‐816 on human liver‐derived tumour cells
Authors: Rubiolo J A , López‐Alonso H , Roel M , Vieytes M R , Thomas O , Ternon E , Vega F V , Botana L M
Published: December 2013

Background and Purpose

Marine sponges have evolved the capacity to produce a series of very efficient chemicals to combat viruses, bacteria, and eukaryotic organisms. It has been demonstrated that several of these compounds have anti‐neoplastic activity. The highly toxic sponge Crambe crambe has been the source of several molecules named crambescidins. Of these, crambescidin‐816 has been shown to be cytotoxic for colon carcinoma cells. To further investigate the potential anti‐carcinogenic effect of crambescidin‐816, we analysed its effect on the transcription of HepG2 cells by microarray analysis followed by experiments guided by the results obtained.

Experimental Approach

After cytotoxicity determination, a transcriptomic analysis was performed to test the effect of crambescidin‐816 on the liver‐derived tumour cell HepG2. Based on the results obtained, we analysed the effect of crambescidin‐816 on cell‐cell adhesion, cell‐matrix adhesion, and cell migration by Western blot, confocal microscopy, flow cytometry and transmission electron microscopy. Cytotoxicity and cell migration were also studied in a variety of other cell lines derived from human tumours.

Key Results

Crambescidin‐816 had a cytotoxic effect on all the cell lines studied. It inhibited cell‐cell adhesion, interfered with the formation of tight junctions, and cell‐matrix adhesion, negatively affecting focal adhesions. It also altered the cytoskeleton dynamics. As a consequence of all these effects on cells crambescidin‐816 inhibited cell migration.

Conclusions and Implications

The results indicate that crambescidin‐816 is active against tumour cells and implicate a new mechanism for the anti‐tumour effect of this compound.
Gating function of isoleucine‐116 in TM‐3 (position III:16/3.40) for the activity state of the CC‐chemokine receptor 5 (CCR5)
Authors: Steen A , Sparre‐Ulrich A H , Thiele S , Guo D , Frimurer T M , Rosenkilde M M
Published: December 2013

Background and Purpose

A conserved amino acid within a protein family indicates a significance of the residue. In the centre of transmembrane helix (TM)‐5, position V:13/5.47, an aromatic amino acid is conserved among class A 7TM receptors. However, in 37% of chemokine receptors – a subgroup of 7TM receptors – it is a leucine indicating an altered function. Here, we describe the significance of this position and its possible interaction with TM‐3 for CCR5 activity.

Experimental Approach

The effects of [L203F]‐CCR5 in TM‐5 (position V:13/5.47), [I116A]‐CCR5 in TM‐3 (III:16/3.40) and [L203F;G286F]‐CCR5 (V:13/5.47;VII:09/7.42) were determined in G‐protein‐ and β‐arrestin‐coupled signalling. Computational modelling monitored changes in amino acid conformation.

Key Results

[L203F]‐CCR5 increased the basal level of G‐protein coupling (20–70% of Emax) and β‐arrestin recruitment (50% of Emax) with a threefold increase in agonist potency. In silico, [I116A]‐CCR5 switched χ1‐angle in [L203F]‐CCR5. Furthermore, [I116A]‐CCR5 was constitutively active to a similar degree as [L203F]‐CCR5. Tyr244 in TM‐6 (VI:09/6.44) moved towards TM‐5 in silico, consistent with its previously shown function for CCR5 activation. On [L203F;G286F]‐CCR5 the antagonist aplaviroc was converted to a superagonist.

Conclusions and Implications

The results imply that an aromatic amino acid in the centre of TM‐5 controls the level of receptor activity. Furthermore, Ile116 acts as a gate for the movement of Tyr244 towards TM‐5 in the active state, a mechanism proposed previously for the β2‐adrenoceptor. The results provide an understanding of chemokine receptor function and thereby information for the development of biased and non‐biased antagonists and inverse agonists.
Burden of copy number variation in common variable immunodeficiency
Authors: Keller M , Glessner J , Resnick E , Perez E , Chapel H , Lucas M , Sullivan K E , Cunningham-Rundles C , Orange J S , Hakonarson H
Published: December 2013

Common variable immunodeficiency (CVID) has been associated recently with a dramatic increase in total copy number variation burden, the cause of which is unclear. In order to explore further the origin and clinical relevance of this finding, we quantified the total genomic copy number variation (CNV) burden in affected patients and evaluated clinical details in relationship to total CNV burden. No correlation was found between total CNV burden and either patient age or time elapsed since symptom onset, and higher total burden did not correlate with incidence of malignancy or other subphenotypes. These findings suggest that the increased CNV burden is static and intrinsic to CVID as a disease.
A rectal bleeding algorithm can successfully reduce emergency admissions
Authors: Patel R. , Clancy R. , Crowther E. , Vannahme M. , Pullyblank A.
Published: December 2013

Aim

Acute lower gastrointestinal bleeding (LGIB) is a common cause of emergency admissions yet rarely requires blood transfusion or radiological/surgical intervention. We aimed to develop a risk assessment tool to identify patients with acute LGIB who can be safely managed in primary care.

Method

We retrospectively applied an existing nomogram to 20 admissions to obtain criteria that could predict the need for transfusion. We simplified the algorithm to three criteria and developed an associated care pathway. If haemoglobin was > 13 g/dl, systolic blood pressure > 115 mmHg and the patient was not anticoagulated, admission could be avoided. These criteria were then applied to 57 prospective patients attending during a 16‐week period. This was implemented with education of primary and secondary care staff, access to an emergency clinic and provision of patient information.

Results

We applied our algorithm and care pathway to 57 patients with uncomplicated rectal bleeding. Thirty‐five per cent (20/57) of potential admissions were avoided. Instead, patients received written information and underwent flexible sigmoidoscopy as outpatients within 6 weeks. One discharged patient was readmitted from endoscopy with severe colitis. There were no other readmissions or complications. Of the 36 patients for whom the algorithm predicted admission was needed, 33% (12/36) were anticoagulated, 94% (34/36) had haemoglobin < 13 g/dl and 42% (15/36) had a systolic blood pressure < 115 mmHg. Only one admission (1.8%) did not fulfil the admission criteria and could have potentially been avoided. Avoidable admissions reduced from 50 to 1.8%.

Conclusion

The application of a simple rectal bleeding algorithm can safely prevent unnecessary admissions.
Post‐operative complications requiring hospitalization more than one yr after living donor liver transplantation
Authors: Takatsuki Mitsuhisa , Soyama Akihiko , Muraoka Izumi , Hara Takanobu , Kinoshita Ayaka , Yamaguchi Izumi , Tanaka Takayuki , Kuroki Tamotsu , Eguchi Susumu
Published: December 2013

Background/Purpose

The long‐term outcomes after living donor liver transplantation (LDLT) have not been clearly established. This retrospective study assessed long‐term outcomes after LDLT through reviewing complications requiring hospitalization more than one yr after engraftment.

Methods

Sixty‐five LDLT recipients alive more than one yr post‐transplantation were enrolled, 37 males and 28 females, with a median age at transplantation of 53 yr (range, 0–68 yr). We reviewed all post‐operative complications requiring hospitalization more than one yr after LDLT.

Results

There were 61 post‐operative complications requiring hospitalization in 43 of the 65 patients (66%), and the majority of these complications were transplantation related (59/61; 97%). Despite this, 43 (78%) of 55 surviving patients had normal liver function at their last follow‐up, and 50 patients (91%) achieved normal activity (Karnofsky score 100%).

Conclusions

More than one‐half of our LDLT recipients required hospitalization more than one yr post‐LDLT to treat a complication. Most were able to maintain their quality of life and liver function with appropriate treatment.
Downward accountability in response to collective actions
Authors: Li Yuan
Published: December 2013

Will autocratic governments implement policies to satisfy the people's demands in order to prevent large scale social unrest? This article explores this question through quantitative analysis of the political economy of public goods provision in Chinese provinces. Data were collected on the number of labour disputes to measure collective actions. My sample includes provincial leaders whose incentives to deliver public goods can either be explained as a result of upward accountability towards the Centre or downward accountability towards the citizens. The confounding factor of upward accountability is ruled out by using two‐step estimation, and the reverse causality between public goods provision and collective actions is controlled by using instrumental variables. This result suggests that provincial leaders will implement policies more in favour of the citizens in response to intensified labour disputes.
Region‐specific impairments in striatal synaptic transmission and impaired instrumental learning in a mouse model of Angelman syndrome
Authors: Hayrapetyan Volodya , Castro Stephen , Sukharnikova Tatyana , Yu Chunxiu , Cao Xinyu , Jiang Yong‐Hui , Yin Henry H.
Published: December 2013

Angelman syndrome (AS) is a neurodevelopmental disorder characterized by mental retardation and impaired speech. Because patients with this disorder often exhibit motor tremor and stereotypical behaviors, which are associated with basal ganglia pathology, we hypothesized that AS is accompanied by abnormal functioning of the striatum, the input nucleus of the basal ganglia. Using mutant mice with maternal deficiency of AS E6‐AP ubiquitin protein ligase Ube3a (Ube3am−/p+), we assessed the effects of Ube3a deficiency on instrumental conditioning, a striatum‐dependent task. We used whole‐cell patch‐clamp recording to measure glutamatergic transmission in the dorsomedial striatum (DMS) and dorsolateral striatum (DLS). Ube3am−/p+ mice were severely impaired in initial acquisition of lever pressing. Whereas the lever pressing of wild‐type controls was reduced by outcome devaluation and instrumental contingency reversal, the performance of Ube3am−/p+ mice were more habitual, impervious to changes in outcome value and action–outcome contingency. In the DMS, but not the DLS, Ube3am−/p+ mice showed reduced amplitude and frequency of miniature excitatory postsynaptic currents. These results show for the first time a selective deficit in instrumental conditioning in the Ube3a deficient mouse model, and suggest a specific impairment in glutmatergic transmission in the associative corticostriatal circuit in AS.
Gene markers in brain tumors: What the epileptologist should know
Authors: Ostrom Quinn , Cohen Mark L. , Ondracek Annie , Sloan Andrew , Barnholtz‐Sloan Jill
Published: December 2013

Gene markers or biomarkers can be used for diagnostic or prognostic purposes for all different types of complex disease, including brain tumors. Prognostic markers can be useful to explain differences not only in overall survival but also in response to treatment and for development of targeted therapies. Multiple genes with specific types of alterations have now been identified that are associated with improved response to chemotherapy and radiotherapy, such as O6‐methylguanine methyltranferase (MGMT) or loss of chromosomes 1p and/or 19q. Other alterations have been identified that are associated with improved overall survival, such as mutations in isocitrate dehydrogenase 1 (IDH1) and/or isocitrate dehydrogenase 2 (IDH2) or having the glioma CpG island DNA methylator phenotype (G‐CIMP). There are many biomarkers that may have relevance in brain tumor–associated epilepsy that do not respond to treatment. Given the rapidly changing landscape of high throughput “omics” technologies, there is significant potential for gaining further knowledge via integration of multiple different types of high genome‐wide data. This knowledge can be translated into improved therapies and clinical outcomes for patients with brain tumors.
The role of functional imaging in the tumor patient
Authors: Wehner Tim
Published: December 2013

Functional imaging studies complement structural magnetic resonance imaging (MRI) in the assessment of patients with brain tumor–associated focal epilepsy. 11C‐Methionine (MET) and 18F‐fluoro‐ethyl‐l‐tyrosine (FET) are amino acid analogues that highlight metabolically active areas in positron emission tomography (PET). Ictal single photon emission computed tomography (SPECT) can provide information about perilesional areas of seizure onset and early propagation. Functional MRI (fMRI) and diffusion tensor imaging (DTI) allow noninvasive identification of potentially eloquent motor, sensory, and language cortical areas and pathways with an accuracy of 10–15 mm compared to electrocortical stimulation (ECS). Repetitive navigated transcranial magnetic stimulation (TMS) allows even more precise noninvasive delineation of primary motor cortex. Information from functional imaging studies helps in the planning of brain tumor biopsies, resections, and the planning of intracranial video–electroencephalography (EEG) studies.
Is an epilepsy presurgical evaluation necessary for mid‐grade and high‐grade brain tumors presenting with seizures?
Authors: Hamer Hajo M. , Hong Seung Bong
Published: December 2013

Patients with epilepsy caused by mid‐grade and high‐grade tumors do not usually undergo formal presurgical epilepsy evaluations before tumor resection. However, a minority of these patients may benefit significantly from just such a structured presurgical evaluation especially when seizure freedom or seizure reduction is a surgical aim in addition to total tumor resection. Typical cases comprise patients with multifocal tumors, tumors with bilateral extension, tumors over eloquent cortex, and the need for differentiation of spells of an uncertain nature, for example, epileptic versus psychogenic nonepileptic seizures. If they are epileptic, the definition of the epileptic lesion versus the epileptogenic zone and eloquent cortex can be another reason for monitoring. In addition to noninvasive recordings, invasive studies that use subdural or depths electrodes can be of special importance in these patients, leading to an exact delineation of the epileptogenic zone, usually extending beyond the epileptic lesion, and allow safe differentiation of epileptic from eloquent cortex.
Resection strategies in tumoral epilepsy: Is a lesionectomy enough?
Authors: Tandon Nitin , Esquenazi Yoshua
Published: December 2013

Resection strategies in patients with tumor‐related epilepsy vary from lesionectomy to larger epilepsy operations with no consensus on optimal approaches. The objective of this study is to use our prior experience in the management of these patients, to derive optimal strategies for the surgical management of epilepsy related to brain tumors. A prospectively compiled database of epilepsy and tumor patients was used to identify patients who underwent surgical resection of a neoplasm but then developed epilepsy, or who presented with epilepsy and were found to harbor a brain tumor. Seizure frequency, histopathology, type of surgical resection, and outcomes were compiled. Of 235 epilepsy surgery patients and 75 low/intermediate grade glioma surgery patients, 13 (5.5%) and 21 (28%) patients, respectively, had tumoral epilepsy. Twenty‐two patients were male and 18 tumors were in the left hemisphere. Tumoral epilepsy occurred predominantly in temporal (50%) and perirolandic (26.5%) locations. The etiology was WHO grade I tumors in 29%, grade II in 35%, and grade III in 33%. In the epilepsy group, following lesionectomy in three and tailored resections in the majority, seizure outcomes were Engel class I in all except one case. In the tumor group, after the initial operation seven additional resections were performed due to seizure recurrence. Outcomes in this group were Engel class 1A in 18 patients and 1B, 1C and IIA in 1 patient each. Drawing upon these data, we propose a classification of the likely reasons of failure in seizure control in patients with tumoral epilepsy. This review reiterates the concept that a complete resection of the lesion is the best approach for dealing with tumors presenting with epilepsy. Overall excellent outcomes can be accomplished following aggressive initial tumor resection, re‐resection in the context of recurrence, and epilepsy style operations in selected patients with a longer history of seizures.
Brain mapping in tumors: Intraoperative or extraoperative?
Authors: Duffau Hugues
Published: December 2013

In nontumoral epilepsy surgery, the main goal for all preoperative investigation is to first determine the epileptogenic zone, and then to analyze its relation to eloquent cortex, in order to control seizures while avoiding adverse postoperative neurologic outcome. To this end, in addition to neuropsychological assessment, functional neuroimaging and scalp electroencephalography, extraoperative recording, and electrical mapping, especially using subdural strip‐ or grid‐electrodes, has been reported extensively. Nonetheless, in tumoral epilepsy surgery, the rationale is different. Indeed, the first aim is rather to maximize the extent of tumor resection while minimizing postsurgical morbidity, in order to increase the median survival as well as to preserve quality of life. As a consequence, as frequently seen in infiltrating tumors such as gliomas, where these lesions not only grow but also migrate along white matter tracts, the resection should be performed according to functional boundaries both at cortical and subcortical levels. With this in mind, extraoperative mapping by strips/grids is often not sufficient in tumoral surgery, since in essence, it allows study of the cortex but cannot map subcortical pathways. Therefore, intraoperative electrostimulation mapping, especially in awake patients, is more appropriate in tumor surgery, because this technique allows real‐time detection of areas crucial for cerebral functions—eloquent cortex and fibers—throughout the resection. In summary, rather than choosing one or the other of different mapping techniques, methodology should be adapted to each pathology, that is, extraoperative mapping in nontumoral epilepsy surgery and intraoperative mapping in tumoral surgery.
An Examination of Cannibalization Effects within the Riverboat Gaming Industry: The Case of Illinois‐Area Casinos
Authors: Gallagher Ryan M.
Published: December 2013

As states become increasingly reliant on taxable casino revenues to augment their budgets, questions concerning optimal casino location have entered into policy dialogues across the country. Notably, policy makers have become concerned with the presence and size of so‐called “cannibalization effects” within the casino industry whereby casinos operating within overlapping markets capture one another's business. However, the size, significance, and underlying mechanics of these effects have received very little attention in the academic literature. Using a unique data panel for the Illinois region that spans over a decade, this paper develops a working framework for identifying the presence of intra‐industry cannibalization effects for the riverboat gaming industry. Evidence suggests cannibalization effects do indeed exist and are largely a function of new casino development, not the expansion of pre‐existing casinos. These effects also attenuate rather quickly with distance.