bluuebunny/crossref_metadata_2025 huggingface dataset:
Origin of radiative recombination and manifestations of localization effects in GaAs/GaNAs core/shell nanowires
Authors: Chen S. L. , Filippov S. , Ishikawa Fumitaro , Chen W. M. , Buyanova I. A.
Published: December 2014

Radiative carrier recombination processes in GaAs/GaNAs core/shell nanowires grown by molecular beam epitaxy on a Si substrate are systematically investigated by employing micro-photoluminescence (μ-PL) and μ-PL excitation (μ-PLE) measurements complemented by time-resolved PL spectroscopy. At low temperatures, alloy disorder is found to cause localization of photo-excited carriers leading to predominance of optical transitions from localized excitons (LE). Some of the local fluctuations in N composition are suggested to lead to strongly localized three-dimensional confining potential equivalent to that for quantum dots, based on the observation of sharp and discrete PL lines within the LE contour. The localization effects are found to have minor influence on PL spectra at room temperature due to thermal activation of the localized excitons to extended states. Under these conditions, photo-excited carrier lifetime is found to be governed by non-radiative recombination via surface states which is somewhat suppressed upon N incorporation.
Quantitative characterization of defect size in graphene using Raman spectroscopy
Authors: Pollard Andrew J. , Brennan Barry , Stec Helena , Tyler Bonnie J. , Seah Martin P. , Gilmore Ian S. , Roy Debdulal
Published: December 2014

The quantitative determination of the lattice disorder present in graphene layers will be crucial if this 2-D material is to be commercialized. Raman spectroscopy has been shown to be a powerful technique for characterizing the density of these defects in graphene layers. Here, we study the evolution of Raman spectra with defect size, for vacancy defects created via ion bombardment. Raman spectroscopy was used to analyze the variation in the D-peak and G-peak intensity ratio for single-layer graphene, whilst the equivalent defects in highly ordered pyrolytic graphite were characterized using scanning tunneling microscopy to determine their lateral dimensions. Vacancy defects of larger lateral sizes were shown to have an associated coalescence of defects at a larger inter-defect distance, through changes in the intensity ratio of the D- and G-peaks, as well as the D-peak width. This is in agreement with a phenomenological model previously determined for calculating the defect density in graphene layers, and experimentally reveals the effect of graphene defect size for Raman spectroscopy measurements. Importantly, these results show how the graphene defect size must be obtained separately to allow the quantification of the graphene defect density using Raman spectroscopy. The measurement of single-layer graphene with several different defect sizes has also enabled an accurate determination of the phase-breaking length of graphene of 2.4 ± 0.6 nm.
Experimental investigation of radiative thermal rectifier using vanadium dioxide
Authors: Ito Kota , Nishikawa Kazutaka , Iizuka Hideo , Toshiyoshi Hiroshi
Published: December 2014

Vanadium dioxide (VO2) exhibits a phase-change behavior from the insulating state to the metallic state around 340 K. By using this effect, we experimentally demonstrate a radiative thermal rectifier in the far-field regime with a thin film VO2 deposited on the silicon wafer. A rectification contrast ratio as large as two is accurately obtained by utilizing a one-dimensional steady-state heat flux measurement system. We develop a theoretical model of the thermal rectifier with optical responses of the materials retrieved from the measured mid-infrared reflection spectra, which is cross-checked with experimentally measured heat flux. Furthermore, we tune the operating temperatures by doping the VO2 film with tungsten (W). These results open up prospects in the fields of thermal management and thermal information processing.
Anomalous decrease of the specific heat capacity at the electrical and thermal conductivity percolation threshold in nanocomposites
Authors: Kim B.-W. , Park S.-H. , Bandaru P. R.
Published: December 2014

We report an unusual specific heat variation in nanotube/polymer composites, related to a reduction in its value at the electrical and the thermal conductivity percolation threshold, with a concomitant increase in the crystallinity. The reduction has been interpreted in terms of the partition of the total number of nanostructures into isolated or clustered/connected entities, the numbers of which vary as a function of the nanotube filler fraction, and the consequent modulation of the entropic characteristics as well as the conductivity.
Electrohydrodynamic direct-writing lithography: An alternative maskless technique for microstructure fabrication
Authors: He Jiankang , Xu Fangyuan , Cao Yi , Liu Yaxiong , Li Dichen , Jin Zhongmin
Published: December 2014

A maskless electrohydrodynamic direct-writing lithographic strategy was presented to flexibly fabricate user-specific micropatterns on silicon substrates. By optimizing the operating parameters, parallel lines as well as lattices with line width of about 2 μm could be stably deposited. The printed micropatterns were found to function as sacrificial template to transfer microstructures into silicon substrates and the etching processes had little effect on the predefined size. It is envisioned that this simple approach provides an alternative to the existing microfabrication techniques, which might enable the wide accessibility of microscale technologies to advance various research fields such as microfluidics, biomedical chips, and microscale tissue engineering.
Phase stabilized homodyne of infrared scattering type scanning near-field optical microscopy
Authors: Xu Xiaoji G. , Gilburd Leonid , Walker Gilbert C.
Published: December 2014

Scattering type scanning near-field optical microscopy (s-SNOM) allows sub diffraction limited spatial resolution. Interferometric homodyne detection in s-SNOM can amplify the signal and extract vibrational responses based on sample absorption. A stable reference phase is required for a high quality homodyne-detected near-field signal. This work presents the development of a phase stabilization mechanism for s-SNOM to provide stable homodyne conditions. The phase stability is found to be better than 0.05 rad for the mid infrared light source. Phase stabilization results in improved near field images and vibrational spectroscopies. Spatial inhomogeneities of the boron nitride nanotubes are measured and compared.
Morphology and chemical termination of HF-etched Si3N4 surfaces
Authors: Liu Li-Hong , Debenedetti William J. I. , Peixoto Tatiana , Gokalp Sumeyra , Shafiq Natis , Veyan Jean-François , Michalak David J. , Hourani Rami , Chabal Yves J.
Published: December 2014

Several reports on the chemical termination of silicon nitride films after HF etching, an important process in the microelectronics industry, are inconsistent claiming N-Hx, Si-H, or fluorine termination. An investigation combining infrared and x-ray photoelectron spectroscopies with atomic force and scanning electron microscopy imaging reveals that under some processing conditions, salt microcrystals are formed and stabilized on the surface, resulting from products of Si3N4 etching. Rinsing in deionized water immediately after HF etching for at least 30 s avoids such deposition and yields a smooth surface without evidence of Si-H termination. Instead, fluorine and oxygen are found to terminate a sizeable fraction of the surface in the form of Si-F and possibly Si-OH bonds. The relatively unique fluorine termination is remarkably stable in both air and water and could lead to further chemical functionalization pathways.
Modeling of high composition AlGaN channel high electron mobility transistors with large threshold voltage
Authors: Bajaj Sanyam , Hung Ting-Hsiang , Akyol Fatih , Nath Digbijoy , Rajan Siddharth
Published: December 2014

We report on the potential of high electron mobility transistors (HEMTs) consisting of high composition AlGaN channel and barrier layers for power switching applications. Detailed two-dimensional (2D) simulations show that threshold voltages in excess of 3 V can be achieved through the use of AlGaN channel layers. We also calculate the 2D electron gas mobility in AlGaN channel HEMTs and evaluate their power figures of merit as a function of device operating temperature and Al mole fraction in the channel. Our models show that power switching transistors with AlGaN channels would have comparable on-resistance to GaN-channel based transistors for the same operation voltage. The modeling in this paper shows the potential of high composition AlGaN as a channel material for future high threshold enhancement mode transistors.
Effect of increasing CO
2
on the terrestrial carbon cycle
Authors: Schimel David , Stephens Britton B. , Fisher Joshua B.
Published: December 2014

Significance

Feedbacks from terrestrial ecosystems to atmospheric CO
2
concentrations contribute the second-largest uncertainty to projections of future climate. These feedbacks, acting over huge regions and long periods of time, are extraordinarily difficult to observe and quantify directly. We evaluated in situ, atmospheric, and simulation estimates of the effect of CO
2
on carbon storage, subject to mass balance constraints. Multiple lines of evidence suggest significant tropical uptake for CO
2
, approximately balancing net deforestation and confirming a substantial negative global feedback to atmospheric CO
2
and climate. This reconciles two approaches that have previously produced contradictory results. We provide a consistent explanation of the impacts of CO
2
on terrestrial carbon across the 12 orders of magnitude between plant stomata and the global carbon cycle.
Experiment, monitoring, and gradient methods used to infer climate change effects on plant communities yield consistent patterns
Authors: Elmendorf Sarah C. , Henry Gregory H. R. , Hollister Robert D. , Fosaa Anna Maria , Gould William A. , Hermanutz Luise , Hofgaard Annika , Jónsdóttir Ingibjörg S. , Jorgenson Janet C. , Lévesque Esther , Magnusson Borgþór , Molau Ulf , Myers-Smith Isla H. , Oberbauer Steven F. , Rixen Christian , Tweedie Craig E. , Walker Marilyn D.
Published: December 2014

Significance

Methodological constraints can limit our ability to quantify potential impacts of climate warming. We assessed the consistency of three approaches in estimating warming effects on plant community composition: manipulative warming experiments, repeat sampling under ambient temperature change (monitoring), and space-for-time substitution. The three approaches showed agreement in the direction of change (an increase in the relative abundance of species with a warmer thermal niche), but differed in the magnitude of change estimated. Experimental and monitoring approaches were similar in magnitude, whereas space-for-time comparisons indicated a much stronger response. These results suggest that all three approaches are valid, but experimental warming and long-term monitoring are best suited for forecasting impacts over the coming decades.
HLA ligandome analysis identifies the underlying specificities of spontaneous antileukemia immune responses in chronic lymphocytic leukemia (CLL)
Authors: Kowalewski Daniel J. , Schuster Heiko , Backert Linus , Berlin Claudia , Kahn Stefan , Kanz Lothar , Salih Helmut R. , Rammensee Hans-Georg , Stevanovic Stefan , Stickel Juliane Sarah
Published: December 2014

Significance

Effective cancer immunotherapy relies on specific immune recognition of tumor-associated and tumor-specific antigens. In chronic lymphocytic leukemia (CLL), the highly variable course of disease implicates an underlying mechanism of tumor control by the immune system. In this study, we directly analyzed the landscape of naturally presented CLL antigens and identified targets conveying immune protection. These novel antigens might be valuable both for patient stratification and for inducing therapeutic antitumor immunity. Taken together, we demonstrate that CLL is subject to spontaneous T-cell responses targeting nonmutated antigens, which are associated with improved patient survival and provide novel options for the immunotherapy of CLL.
Ancestral duplications and highly dynamic opsin gene evolution in percomorph fishes
Authors: Cortesi Fabio , Musilová Zuzana , Stieb Sara M. , Hart Nathan S. , Siebeck Ulrike E. , Malmstrøm Martin , Tørresen Ole K. , Jentoft Sissel , Cheney Karen L. , Marshall N. Justin , Carleton Karen L. , Salzburger Walter
Published: December 2014

Significance

Gene and whole-genome duplications are important evolutionary forces promoting organismal diversification. Teleost fishes, for example, possess many gene duplicates responsible for photoreception (opsins), which emerged through gene duplication and allow fishes to adapt to the various light conditions of the aquatic environment. Here, we reevaluate the evolutionary history of the violet-blue–sensitive opsins [short wavelength-sensitive 2 (SWS2)] in modern teleosts using next generation genome sequencing. We uncover a gene duplication event specific to the most diverse lineage of vertebrates (the percomorphs) and show that SWS2 evolution was highly dynamic and involved gene loss, pseudogenization, and gene conversion. We, thus, clarify previous discrepancies regarding opsin annotations. Our study highlights the importance of integrative approaches to help us understand how species adapt and diversify.
Bacterial growth laws reflect the evolutionary importance of energy efficiency
Authors: Maitra Arijit , Dill Ken A.
Published: December 2014

Significance

Bacterial cells are remarkable machines. When food is present, bacteria shift gears into a fast-growth mode, whereby they duplicate all their proteins quickly. Cells do this by producing proportionately more ribosomes relative to other proteins. Ribosomes are the 55-protein complexes that a cell makes to synthesize all the cells proteins. Here, we develop a mathematical model of the mechanism of the cell’s gear-shifting and energy utilization under different growth conditions. A major conclusion from this modeling is that we can understand an evolutionary choice made by bacteria. We find that fast growing cells operate close to their optimal energy efficiency, which is a balance between the rates of translation and turnover of proteins and ribosomal assembly.
Distinct dopamine neurons mediate reward signals for short- and long-term memories
Authors: Yamagata Nobuhiro , Ichinose Toshiharu , Aso Yoshinori , Plaçais Pierre-Yves , Friedrich Anja B. , Sima Richard J. , Preat Thomas , Rubin Gerald M. , Tanimoto Hiromu
Published: December 2014

Significance

A biologically relevant event such as finding food under starvation conditions or being poisoned can drive long-term memory (LTM) in a single training session. Neuronal mechanisms by which such a strong reward or punishment induces stable memory are poorly understood. Here we show that distinct subsets of dopamine neurons signal reward for short- and long-term appetitive memories in
Drosophila.
The temporal dynamics of memory components triggered by the distinct reward signals are complementary, and together contribute to a temporally stable memory retention. Two subsets of dopamine neurons could signal different reward properties: sweet taste and nutritional value of sugar. Sugar reward is thus intricately encoded in the fly brain, given the importance of long-lasting food-related memory in survival.
Mouse BRWD1 is critical for spermatid postmeiotic transcription and female meiotic chromosome stability
Authors: Pattabiraman Shrivatsav , Baumann Claudia , Guisado Daniela , Eppig John J. , Schimenti John C. , De La Fuente Rabindranath
Published: December 2014

Postmeiotic gene expression is essential for development and maturation of sperm and eggs. We report that the dual bromodomain-containing protein BRWD1, which is essential for both male and female fertility, promotes haploid spermatid–specific transcription but has distinct roles in oocyte meiotic progression. Brwd1 deficiency caused down-regulation of ∼300 mostly spermatid-specific transcripts in testis, including nearly complete elimination of those encoding the protamines and transition proteins, but was not associated with global epigenetic changes in chromatin, which suggests that BRWD1 acts selectively. In females, Brwd1 ablation caused severe chromosome condensation and structural defects associated with abnormal telomere structure but only minor changes in gene expression at the germinal vesicle stage, including more than twofold overexpression of the histone methyltransferase MLL5 and LINE-1 elements transposons. Thus, loss of BRWD1 function interferes with the completion of oogenesis and spermatogenesis through sexually dimorphic mechanisms: it is essential in females for epigenetic control of meiotic chromosome stability and in males for haploid gene transcription during postmeiotic sperm differentiation.
BRWD1 shows its gender bias
Authors: Leslie Mitch
Published: December 2014

Protein necessary for fertility has distinct roles in sperm and eggs.
Angioedema–Urticaria Due to Acitretin
Authors: Solak Berna , Metin Nurcan , Erdem Mustafa Teoman
Published: December 2014

Acitretin is a synthetic oral retinoid that has been used for a number of dermatological diseases. Several side effects of acitretin have been reported such as teratogenicity, cheilitis, xerosis, dyslipidemia, and photosensitivity. Many drugs, mainly antibiotics and nonsteroidal anti-inflammatory drugs, can cause angioedema–urticaria. We present the case of angioedema–urticaria due to acitretin, confirmed by oral provocation test, in a 61-year-old man with psoriasis. To the best of our knowledge, only 1 case of angioedema due to oral acitretin has been reported in the literature so far. We report this case to draw attention that acitretin may cause angioedema–urticaria and to inform patients about this risk besides other side effects due to acitretin.
A Literature Review Revisiting Phenytoin-Induced Sinus Arrest
Authors: Parsai Shireen , Hariri Imad , Taleb Mohammad , Yoon Youngsook
Published: December 2014

Classically, phenytoin (PTN) infusion for the treatment of status epilepticus has been proven to be associated with cardiovascular toxicity, including dysrhythmias, hypotension, and cardiovascular collapse. Subsequently, fosphenytoin (FOS) was introduced on the market in 1997 with claims of having less cardiac toxicity. However, since then, many accounts of cardiac events have been reported undermining these claims. FOS gained popularity due to its water solubility, which allows 3 times faster infusion in comparison with PTN with less venous irritation and local toxicity. FOS is the phosphate ester prodrug of PTN and is rapidly converted to PTN independent of the dose and rate of administration. Intravenous FOS and PTN are bioequivalent. Adverse cardiac effects of both intravenous FOS and PTN have been correlated to the rate of infusion, concentration of the agent, known risk factors, or pre-existing hypersensitivity, and most cases have been identified after infusing a loading dose of these medications. This case report is unique, in that, the patient developed sinus arrest while concurrently receiving oral PTN and intravenous FOS. Clinicians should be more cognizant of the association of FOS and PTN with adverse cardiac events. Baseline electrocardiogram should be obtained on all patients prescribed FOS or PTN to identify underlying cardiac problems that may place the patient in a higher risk category. Telemetry should be performed on all patients receiving PTN in an inpatient setting.
Detecting event-related recurrences by symbolic analysis: applications to human language processing
Authors: beim Graben Peter , Hutt Axel
Published: December 2014

Quasi-stationarity is ubiquitous in complex dynamical systems. In brain dynamics, there is ample evidence that event-related potentials (ERPs) reflect such quasi-stationary states. In order to detect them from time series, several segmentation techniques have been proposed. In this study, we elaborate a recent approach for detecting quasi-stationary states as recurrence domains by means of recurrence analysis and subsequent symbolization methods. We address two pertinent problems of contemporary recurrence analysis: optimizing the size of recurrence neighbourhoods and identifying symbols from different realizations for sequence alignment. As possible solutions for these problems, we suggest a maximum entropy criterion and a Hausdorff clustering algorithm. The resulting recurrence domains for single-subject ERPs are obtained as partition cells reflecting quasi-stationary brain states.
Changes of sleep-stage transitions due to ageing and sleep disorder
Authors: Schlemmer A. , Parlitz U. , Luther S. , Wessel N. , Penzel T.
Published: December 2014

Transition patterns between different sleep stages are analysed in terms of probability distributions of symbolic sequences for young and old subjects with and without sleep disorder. Changes of these patterns due to ageing are compared with variations of transition probabilities due to sleep disorder.
Assessing levels of consciousness with symbolic analysis
Authors: Lee UnCheol , Blain-Moraes Stefanie , Mashour George A.
Published: December 2014

‘Covert consciousness’ is a state in which consciousness is present without the capacity for behavioural response, and it can occur in patients with intraoperative awareness or unresponsive wakefulness syndrome. To detect and prevent this undesirable state, it is critical to develop a reliable neurobiological assessment of an individual's level of consciousness that is independent of behaviour. One such approach that shows potential is measuring surrogates of cortical communication in the brain using electroencephalography (EEG). EEG is practicable in clinical application, but involves many fundamental signal processing problems, including signal-to-noise ratio and high dimensional complexity. Symbolic analysis of EEG can mitigate these problems, improving the measurement of brain connectivity and the ability to successfully assess levels of consciousness. In this article, we review the problem of covert consciousness, basic neurobiological principles of consciousness, current methods of measuring brain connectivity and the advantages of symbolic processing, with a focus on symbolic transfer entropy (STE). Finally, we discuss recent advances and clinical applications of STE and other symbolic analyses to assess levels of consciousness.
Detection of Norovirus and Sapovirus from diarrheic dogs and cats in Japan
Authors: Soma Takehisa , Nakagomi Osamu , Nakagomi Toyoko , Mochizuki Masami
Published: December 2014

Norovirus (NoV) and sapovirus (SaV) are important causes of human diarrhea. In this study, between 2007 and 2014 fecal samples were collected from 97 dogs and 83 cats with diarrhea and examined to determine the prevalence of NoV and SaV infections in Japan. To detect caliciviruses, approximately 300 bases targeting the polymerase gene were amplified using RT‐PCR and subjected to phylogenetic and homology analyses. Specific PCR products were obtained from four canine and nine feline samples: two canine and one feline isolate were classified as NoV, two canine isolates as SaV and the remaining eight feline isolates as vesivirus (VeV). The three NoV isolates were classified into the same clade as that of known canine and feline NoVs; their homologies (75.9–92.3%) were higher than those with human genogroup IV (GIV) NoVs (59.1–65.9%). The homology of the feline NoV isolate with previously reported feline NoV isolates was particularly high (91.7–92.3%). Regarding SaV, the two canine isolates were classified into the same clade as known canine SaVs and their homologies (72.5–86.5%) were higher than those with other mammal SaVs (20.7–58.0%). The eight feline VeV isolates were assumed to be feline calicivirus. The present study is the first report of the presence of NoV‐ and SaV‐infected dogs and cats in Japan. The findings suggest there are species‐specific circulations of NoV and SaV among dogs and cats, in Japan.
Global women's health: current clinical trials in low‐ and middle‐income countries
Authors: Merriel A , Harb HM , Williams H , Lilford R , Coomarasamy A
Published: December 2014

Background

Clinical trials in low‐ and middle‐income countries (LMICs) are necessary to develop evidence‐based approaches to improve women's health. Understanding what research is currently being conducted will allow the identification of research gaps, avoidance of duplication, planning of future studies, collaboration amongst research groups, and geographical targeting for research investments.

Objectives

To provide an overview of active women's health trials in LMICs.

Search strategy

The World Health Organization's International Clinical Trials Registry Platform was searched for trials registered between 1 April 2012 and 31 March 2014.

Selection criteria

Selected trials were randomised, conducted in LMICs, active, and with a women's health intervention or a significant outcome for the woman.

Data collection and analysis

Two reviewers extracted data. Analysis included geographical spread, speciality areas, pre‐enrolment registration, study size, and funders.

Main results

Of the 8966 records, 509 were eligible for inclusion. Gynaecology trials made up 57% of the research, whereas the remaining 43% of trials were in obstetrics. Research activity focused on fertility (17%), the antenatal period (15%), benign gynaecology (14%), intrapartum care (9%), and pre‐invasive disease and cancers (8%). The majority of trials (84%) took place in middle‐income countries (MICs). In low‐income countries (LICs) 83% of research investigated obstetrics, and in MICs 60% of research investigated gynaecology. Most trials (80%) had a sample size of 500 or fewer participants. The median size of trials in LICs was 815 compared with 128 in MICs. Pre‐enrolment registration occurred in 54% of trials. The majority (62%) of trials were funded locally.

Authors' conclusions

Many LMICs are active in women's health research. The majority of registered trials are located in MICs; however, the trials in LICs are often larger. The focus of research in MICs may be driven by local priorities and funding, with fertility being highly researched. In LICs, pregnancy is the focus, perhaps reflecting the international prioritisation of maternal health.
Shock index: an effective predictor of outcome in postpartum haemorrhage?
Authors: Nathan HL , El Ayadi A , Hezelgrave NL , Seed P , Butrick E , Miller S , Briley A , Bewley S , Shennan AH
Published: December 2014

Objectives

To compare the predictive value of the shock index (SI) with conventional vital signs in postpartum haemorrhage (PPH), and to establish ‘alert’ thresholds for use in low‐resource settings.

Design

Retrospective cohort study.

Setting

UK tertiary centre.

Population

Women with PPH ≥1500 ml (n = 233).

Methods

Systolic blood pressure (BP), diastolic BP, mean arterial pressure, pulse pressure, heart rate (HR) and SI (HR/systolic BP) were measured within the first hour following PPH. Values measured at the time of highest SI were selected for analysis. The area under the receiver operating characteristic curve (AUROC) for each parameter, used to predict admission to an intensive care unit and other adverse outcomes, was calculated. Sensitivity, specificity and negative/positive predictive values determined thresholds of the best predictor.

Main outcome measures

Intensive care unit (ICU) admission, blood transfusion ≥4 iu, haemoglobin level <7 g/dl, and invasive surgical procedures.

Results

Shock index has the highest AUROC to predict ICU admissions (0.75 for SI [95% CI 0.63–0.87] compared with 0.64 [95% CI 0.44–0.83] for systolic BP). SI compared favourably for other outcomes: SI ≥0.9 had 100% sensitivity (95% CI 73.5–100) and 43.4% specificity (95% CI 36.8–50.3), and SI ≥1.7 had 25.0% sensitivity (95% CI 5.5–57.2) and 97.7% specificity (CI 94.8–99.3), for predicting ICU admission.

Conclusions

Shock index compared favourably with conventional vital signs in predicting ICU admission and other outcomes in PPH, even after adjusting for confounding; SI <0.9 provides reassurance, whereas SI ≥1.7 indicates a need for urgent attention. In low‐resource settings this simple parameter could improve outcomes. It was not possible to adjust for resuscitative measures administered following vital sign measurement that may have influenced the outcome.
The global met need for emergency obstetric care: a systematic review
Authors: Holmer H , Oyerinde K , Meara JG , Gillies R , Liljestrand J , Hagander L
Published: December 2014

Background

Of the 287 000 maternal deaths every year, 99% happen in low‐ and middle‐income countries. The vast majority could be averted with timely access to appropriate emergency obstetric care (EmOC). The proportion of women with complications of pregnancy or childbirth who actually receive treatment is reported as ‘Met need for EmOC’.

Objective

To estimate the global met need for EmOC and to examine the correlation between met need, maternal mortality ratio and other indicators.

Search strategy

A systematic review was performed according to the PRISMA guidelines. Searches were made in PubMed, EMBASE and Google Scholar.

Selection criteria

Studies containing data on met need in EmOC were selected.

Data collection and analysis

Analysis was performed with data extracted from 62 studies representing 51 countries. World Bank data were used for univariate and multiple linear regression.

Main results

Global met need for EmOC was 45% (IQR: 28–57%), with significant disparity between low‐ (21% [12–31%]), middle‐ (32% [15‐56%]), and high‐income countries (99% [99–99%]), (P = 0.041). This corresponds to 11.4 million (8.8–14.8) untreated complications yearly and 951 million (645–1174 million) women without access to EmOC. We found an inverse correlation between met need and maternal mortality ratio (r = −0.42, P < 0.001). Met need was significantly correlated with the proportion of births attended by skilled birth attendants (β = 0.53 [95% CI 0.41–0.65], P < 0.001).

Authors’ conclusions

The results suggest a considerable inadequacy in global met need for EmOC, with vast disparities between countries of different income levels. Met need is a powerful indicator of the response to maternal mortality and strategies to improve EmOC act in synergy with the expansion of skilled birth attendance.
Next‐generation sequencing workflow for assembly of nonmodel mitogenomes exemplified with North Pacific albatrosses (Phoebastria spp.)
Authors: Lounsberry Z. T. , Brown S. K. , Collins P. W. , Henry R. W. , Newsome S. D. , Sacks B. N.
Published: December 2014

Use of complete mitochondrial genomes (mitogenomes) can greatly increase the resolution achievable in phylogeographic and historical demographic studies. Using next‐generation sequencing methods, it is now feasible to efficiently sequence mitogenomes of large numbers of individuals once a reference mitogenome is available. However, assembling the initial mitogenomes of nonmodel organisms can present challenges, for example, in birds, where mtDNA is often subject to gene rearrangements and duplications. We developed a workflow based on Illumina paired‐end, whole‐genome shotgun sequencing, which we used to generate complete 19‐kilobase mitogenomes for each of three species of North Pacific albatross, a group of birds known to carry a tandem duplication. Although this duplication had been described previously, our procedure did not depend on this prior knowledge, nor did it require a closely related reference mitogenome (e.g. a mammalian mitogenome was sufficient). We employed an iterative process including de novo assembly, reference‐guided assembly and gap closing, which enabled us to detect duplications, determine gene order and identify sequence for primer positioning to resolve any mitogenome ambiguity (via minimal targeted Sanger sequencing). We present full mtDNA annotations, including 22 tRNAs, 2 rRNAs, 13 protein‐coding genes, a control region and a duplicated feature for all three species. Pairwise comparisons supported previous hypotheses regarding the phylogenetic relationships within this group and occurrence of a shared tandem duplication. The resulting mitogenome sequences will enable rapid, high‐throughput NGS mitogenome sequencing of North Pacific albatrosses via direct reference‐guided assembly. Moreover, our approach to assembling mitogenomes should be applicable to any taxon.
Elevated frequencies of CD4+IL‐21+T, CD4+IL‐21R+T and IL‐21+Th17 cells, and increased levels of IL‐21 in bleomycin‐induced mice may be associated with dermal and pulmonary inflammation and fibrosis
Authors: Lei Ling , He Zhi‐Yi , Zhao Cheng , Sun Xue‐Jiao , Zhong Xiao‐Ning
Published: December 2014

Aim

Systemic sclerosis (SSc) is characterized by immune abnormalities, progressive fibrosis of the skin and internal organs, and microvascular injury and damage. Interleukin‐21 receptor (IL‐21R) is expressed in the epidermis from patients with SSc. However, information describing the role of IL‐21 in SSc is limited.

Methods

We established a mouse model of bleomycin (BLM)‐induced fibrosis. The frequency of CD4+IL‐21+T, CD4+IL‐21R+T and IL‐21+Th17 cells in peripheral blood, skin and lungs of BLM‐induced mice were detected by flow cytometry; IL‐21 levels in the peripheral blood were evaluated by enzyme‐linked immunosorbent assay (ELISA). CD4+T cells were isolated from the spleen of BLM‐induced and control mice and cultured in vitro alone or in the presence of mrIL‐21 or mrIL‐21 plus transforming growth factor (TGF)‐β1. The frequency of Th17 cells was detected by flow cytometry; levels of IL‐17 were evaluated by ELISA, and the expression of IL‐17A and retinoic‐acid‐receptor‐related orphan receptors gamma t (RORγt) messenger RNA were analyzed by real‐time polymerase chain reaction.

Results

Compared to control mice, the frequency of CD4+IL‐21+T, CD4+21R+T and IL‐21+Th17 cells and the levels of IL‐21 were significantly increased in BLM‐induced mice. The frequency of CD4+IL‐21+T, CD4+21R+T and IL‐21+Th17 cells and the levels of IL‐21 were correlated with dermal and pulmonary inflammation and fibrosis. In vitro analyses indicate that IL‐21 promoted the differentiation of Th17 cells from CD4+ cells isolated from the spleen of BLM‐induced mice.

Conclusion

IL‐21 may play an important role in the pathogenesis of SSc as a Th17 effector cytokine, and IL‐21 may induce the differentiation of Th17 cells in the BLM‐induced SSc mouse model.
Treatment of low back pain: Second extended follow up of an original trial (NCT00600197) comparing a multidisciplinary group‐based rehabilitation program with oral drug treatment alone up to 30 months
Authors: Tavafian Sedigheh S. , Jamshidi Ahmad R. , Mohammad Kazem
Published: December 2014

Background

The aim of this study is to investigate the effects of the extended 30‐month follow‐up of an original trial (NCT00600197) which has been published in the Clinical Journal of Pain.

Methods

Seventy‐four percent (146/197) of the participants who had taken part in the original study, including 69 patients in the intervention group and 77 patients in the control group, were followed up to 30 months after intervention. The intervention group continued receiving monthly motivational consultation and booster classes plus oral medication but the other group received just medication. Data on measures from the Short Form 36 (SF‐36), Quebec Disability Scale (QDS) and Ronald Morris Disability Questionnaire (RDQ) were collected at 3‐, 6‐, 12‐, 18‐, 24‐ and 30‐month follow‐ups and analyzed through repeated measures analysis of variance.

Results

The two groups were comparable regarding all baseline characteristics (P > 0.05) except for education level and mental health, which were better in the intervention group (P < 0.05). The two groups improved regarding all studied variables over time up to 30 months (P < 0.001). Moreover, the intervention group in comparison with the control group had consistently better outcomes regarding all variables. There were significant differences within each group by time in terms of mental health (P = 0.01) and disability measured through QDS (P = 0.005) and RDQ (P = 0.014).

Conclusion

The proposed multidisciplinary program could improve mental health and disability up to 30 months in chronic low back pain patients.
Reduced efficacy of transcatheter and surgical revascularization in Takayasu arteritis
Authors: Sammel Anthony M. , Wolfenden Hugh D. , Joshua Fredrick , Jepson Nigel
Published: December 2014

A 55‐year‐old woman with newly diagnosed Takayasu arteritis was followed for 7 years, during which time she underwent bare metal stenting, drug eluting stenting and coronary bypass grafting for critical coronary and renal artery stenoses. Interventions were initially successful but restenosis occurred within 24 months for all modalities. In contrast, native vessel disease was largely stable after the introduction of immunosuppressive therapy. We advocate a conservative revascularization approach in Takayasu arteritis in the absence of critical end organ ischemia and early optimization of medical therapy.
Histological transformation from non‐small cell to small cell lung carcinoma after treatment with epidermal growth factor receptor‐tyrosine kinase inhibitor
Authors: Kim Woo‐Jin , Kim Sunmin , Choi Hayoung , Chang Jinsun , Shin Hong‐Joon , Park Cheol‐Kyu , Oh In‐Jae , Kim Kyu‐Sik , Kim Young‐Chul , Choi Yoo‐Duk
Published: December 2014

Several cases of acquired resistance in patients with activating epidermal growth factor receptor (EGFR) mutation have been reported. However, rare clinical cases exist of a transformation to small cell lung cancer (SCLC) following treatment with EGFR‐tyrosine kinase inhibitors (TKIs). We report a case of non‐small cell lung cancer (NSCLC) with L858R mutation at the time of diagnosis. After failure of EGFR‐TKI therapy, we performed additional histopathologic examinations. We confirmed that the patient had a histological transformation from NSCLC to SCLC. We performed chemotherapy with etoposide and cisplatin against the SCLC and radiologic findings were improved.
Incidence of Positive Ventricular Late Potentials Differs in Postural Changes among Supine, Left, and Right Lateral Decubitus, and Prone and Sitting Positions in Brugada Syndrome
Authors: Yoshioka Koichiro , Amino Mari , Nakamura Mari , Kanda Shigetaka , Kobayashi Yoshinori , Ikari Yuji , Shima Makiyoshi , Tanabe Teruhisa
Published: December 2014

Background

High‐risk patients with Brugada syndrome (BrS) have inherent late potential (LP) fluctuations that might be explained by autonomic activity, electrolyte abnormality, and body temperature changes. However, the correlation between postural changes and LP determinates remains unknown.

Methods

Forty patients with BrS (38 men, 43.9 ± 13.5 years) and 15 controls (15 men, 42.4 ± 11.2 years) were enrolled. LP variations were investigated at five body positions using high‐resolution ambulatory monitoring electrocardiography (HR‐ambulatory ECG). The HR‐ambulatory ECG was recorded for 3 hours and LP parameters (fQRSd, LAS40, and RMS40) were obtained for at least 15 minutes in each at the supine, left and right lateral decubitus, and prone and sitting positions.

Results

Determinate LP in the BrS group was significantly abnormal in all positions. Among the five body positions, positive LP were much more frequent in the supine and left and right lateral decubitus positions than in the prone and sitting positions and normalized in the last two positions in patients with BrS. RMS40 variance by postural change was significantly larger in the coved group than in the saddle back group. Determinate LP improved in the sitting position compared to the supine position in the coved group.

Conclusions

Positive LP findings normalized in the sitting position in patients in the coved BrS group with a resuscitation history, suggesting that depolarization instability might be related to the risk of fatal ventricular arrhythmia. Posture‐induced LP variance should be examined using HR‐ambulatory ECG analysis in patients with BrS.
Individual maternal and child exposure to antibiotics in hospital – a national population‐based validation study
Authors: Almqvist C , Örtqvist AK , Gong T , Wallas A , Ahlén KM , Ye W , Lundholm C
Published: December 2014

Aim

Exposure to antibiotics in early life may affect future health. Most antibiotics are prescribed in outpatient care, but inpatient exposure is also important. We estimated how specific diagnoses in hospitals corresponded to individual antibiotic exposure.

Methods

All pregnant women and children from birth to 5 years of age with infectious diseases and common inpatient diagnoses between July 2005 and November 2011 were identified from the Swedish National Patient Register. Random samples of individuals from predefined groups were drawn, and medical records received from the clinics were manually reviewed for antibiotics.

Results

Medical records for 4319 hospital visits were requested and 3797 (88%) were received. A quarter (25%) of children diagnosed as premature had received antibiotics, and in children from one to 5 years of age, diagnoses associated with bacterial infections were more commonly treated with antibiotics (62.4–90.6%) than those associated with viruses (6.3–22.2%). Pregnant women who had undergone a Caesarean section were more likely to be treated with antibiotics than those who had had a vaginal delivery (40.1% versus 11.1%).

Conclusion

This study defines the proportion of new mothers and young children who received individual antibiotic treatment for specific inpatient diagnoses in Sweden and provides a useful basis for future studies focusing on antibiotic use.
Self‐reflection, growth goals, and academic outcomes: A qualitative study
Authors: Travers Cheryl J. , Morisano Dominique , Locke Edwin A.
Published: December 2014

Background

Goal‐setting theory continues to be among the most popular and influential theories of motivation and performance, although there have been limited academic applications relative to applications in other domains, such as organizational psychology.

Aims

This paper summarizes existing quantitative research and then employs a qualitative approach to exploring academic growth via an in‐depth reflective growth goal‐setting methodology.

Sample

The study focuses on 92 UK final‐year students enrolled in an elective advanced interpersonal skills and personal development module, with self‐reflection and growth goal setting at its core.

Method

Qualitative data in the form of regular reflective written diary entries and qualitative questionnaires were collected from students during, on completion of, and 6 months following the personal growth goal‐setting programme.

Results

About 20% of students' self‐set growth goals directly related to academic growth and performance; students reported that these had a strong impact on their achievement both during and following the reflective programme. Growth goals that were indirectly related to achievement (e.g., stress management) appeared to positively impact academic growth and other outcomes (e.g., well‐being). A follow‐up survey revealed that growth goal setting continued to impact academic growth factors (e.g., self‐efficacy, academic performance) beyond the reflective programme itself.

Conclusions

Academic growth can result from both academically direct and indirect growth goals, and growth goal setting appears to be aided by the process of simultaneous growth reflection. The implications for promoting academic growth via this unique learning and development approach are discussed.
The amoeboidal Dictyostelium aquaporin AqpB is gated via Tyr216 and aqpB gene deletion affects random cell motility
Authors: von Bülow Julia , Golldack André , Albers Tineke , Beitz Eric
Published: December 2014

Background information

Regulation of aquaporin (AQPs) water channels mostly occurs on the transcriptional level or by intracellular trafficking. Direct AQP gating is comparatively rare and is described mainly for fungi and plants. Earlier, we identified a gated water‐specific AQP in Dictyostelium discoideum, AqpB, which is opened by truncation of an extended intracellular loop D (AqpB Δ208–219).

Results

We show that Tyr216 of loop D is a key residue in the gating mechanism possibly involving phosphorylation. Mutation of Tyr216 to aspartate or glutamate initiated water permeability (Pf = 69 μm/s) to the same extent as AqpB Δ208–219, whereas neither replacement of Tyr216 by a positive arginine (Y216R) nor introduction of a negative charge in a neighbouring position (T217D) opened the channel. We overexpressed AqpB wildtype and AqpB Δ208–219 as GFP fusion constructs in Dictyostelium amoebae and found that the truncated, permanently open AqpB yielded cells with reduced capability to cope with hypotonic stress. Genetic deletion of aqpB yielded a strain with significantly reduced speed of random motility (4.5 μm/min vs. 6.3 μm/min of wildtype cells). Yet, chemotaxis towards folate and cAMP was unaffected. In this context, we identified a second, so‐far uncharacterised amoeboidal AQP, AqpD, whose role in directed cell locomotion needs to be established.

Conclusion

Our data add to the completion of the Dictyostelium model for cell motility and show that knowledge on the expression, permeability properties and localisation of amoeboidal AQPs are crucial for further development of the system.
Synthesis and Structure–Activity Relationships of Triazaspirodecanone Derivatives as Nociceptin/Orphanin FQ Receptor Ligands
Authors: Corrado Sandra , Battisti Umberto M. , Sorbi Claudia , Tait Annalisa , Malfacini Davide , Camarda Valeria , Calò Girolamo , Brasili Livio
Published: December 2014

Several spiroxatrine derivatives were synthesized and evaluated as potential NOP receptor ligands. Structural modifications of the 1,4‐benzodioxane moiety of spiroxatrine have been the focus of this research project. The structure–activity relationships that emerged indicate that the presence of an H‐bond donor group (hydroxyl group) is more favorable for NOP activity when it is positioned α with respect to the CH2 linked to the 1‐phenyl‐1,3,8‐triaza‐spiro[4.5]decan‐4‐one portion. Moreover, cis diastereoisomers of the hydroxyl derivatives4 and 22 show a moderately higher degree of stereoselectivity than trans isomers. In particular, the spiropiperidine derivative cis‐4 has submicromolar agonistic activity, and it will be the reference compound for the design and synthesis of new NOP agonists.
Simulated training in colonoscopic stenting of colonic strictures: validation of a cadaver model
Authors: Iordache F. , Bucobo J. C. , Devlin D. , You K. , Bergamaschi R.
Published: December 2014

Aim

There are currently no available simulation models for training in colonoscopic stent deployment. The aim of this study was to validate a cadaver model for simulation training in colonoscopy with stent deployment for colonic strictures.

Method

This was a prospective study enrolling surgeons at a single institution. Participants performed colonoscopic stenting on a cadaver model. Their performance was assessed by two independent observers. Measurements were performed for quantitative analysis (time to identify stenosis, time for deployment, accuracy) and a weighted score was devised for assessment. The Mann–Whitney U‐test and Student's t‐test were used for nonparametric and parametric data, respectively. Cohen's kappa coefficient was used for reliability.

Results

Twenty participants performed a colonoscopy with deployment of a self‐expandable metallic stent in two cadavers (groups A and B) with 20 strictures overall. The median time was 206 s. The model was able to differentiate between experts and novices (P = 0. 013). The results showed a good consensus estimate of reliability, with kappa = 0.571 (P < 0.0001).

Conclusion

The cadaver model described in this study has content, construct and concurrent validity for simulation training in colonoscopic deployment of self‐expandable stents for colonic strictures. Further studies are needed to evaluate the predictive validity of this model in terms of skill transfer to clinical practice.