bluuebunny/crossref_metadata_2025 huggingface dataset:
Hole localization energy of 1.18 eV in GaSb quantum dots embedded in GaP
Authors: Bonato Leo , Arikan Ismail Firat , Desplanque Ludovic , Coinon Christophe , Wallart Xavier , Wang Yi , Ruterana Pierre , Bimberg Dieter
Published: September 2016

Self‐organized GaSb quantum dots are embedded in GaP by molecular beam epitaxy and ‐diodes are fabricated. The structure of the sample is investigated using transmission electron microscopy with atomic resolution. The presence of quantum dots on top of a wetting layer and interdiffusion processes between Sb and P are observed. The localization energy, capture cross‐section, and storage time of holes in the ground state of the quantum dots are determined via deep‐level transient spectroscopy. Their localization energy of eV is found to agree with the theoretical prediction of 1.4 eV once the observed interdiffusion is taken into account. A storage time of holes of  days at room temperature is calculated, marking an improvement of 3 orders of magnitude from previous record figures. GaSb/GaP quantum dots are, thus, promising candidates for future non‐volatile DRAMs or fast Flash.

Schematic representation of the quantum dots (left) and of the valence band in their vicinity (right). The localization energy is marked on the scheme. The localization of the quantum dots prevents thermal emission of holes, generating a storage time at room temperature of 3.9 days.
Nitrogen isotopic discrimination in dietary amino acids: The threonine anomaly
Authors: Wallace Carmichael J. A. , Hedges Robert E. M.
Published: September 2016

Rationale

The “Threonine Anomaly” relates to an observation made 25 years ago on the change in Thr nitrogen isotopic ratio in mammalian metabolism. Unlike all other amino acids, Thr in body protein is found to be depleted (rather than enriched) in 15N relative to dietary Thr. Interpreting isotopic discrimination has become a useful source of ecological and palaeodietary information and it is desirable that the underlying processes are understood.

Methods

The principal enzyme of threonine catabolism, suggested to be responsible for the anomaly, threonine dehydratase, was prepared from rat liver. A time course of incubation of the enzyme with pure threonine was followed, and samples of residual threonine prepared for isotopic analysis by combustion in an automated carbon and nitrogen analyser coupled to a continuous flow isotope ratio mass spectrometer.

Results

We show experimentally, in vitro, that the enzymic reaction catabolising Thr cannot be responsible for its 15N depletion. Plots of delta 15N against both reaction time course and percentage completion show in fact an accelerating enrichment.

Conclusions

A previously advanced suggestion that the unique catabolic mechanism for threonine was responsible for the anomalous depletion in 15N is clearly not the case. We therefore offer alternative explanations, based on threonine's role at an organismal rather than cellular level. Copyright © 2016 John Wiley & Sons, Ltd.
Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry imaging of ochratoxin A and fumonisins in mold‐infected food
Authors: Hickert Sebastian , Cramer Benedikt , Letzel Matthias C. , Humpf Hans‐Ulrich
Published: September 2016

Rationale

Mycotoxins are toxic secondary metabolites produced by various fungi. Their distribution within contaminated material is of high interest to obtain insight into infection mechanisms and the possibility of reducing contamination during food processing.

Methods

Various vegetable foodstuffs were infected with fungi of the genera Fusarium and Aspergillus. The localization of the produced mycotoxins was studied by matrix‐assisted laser desorption/ionization time‐of flight mass spectrometry imaging (MALDI‐MSI) of cryosections obtained from infected material. The results were confirmed by high‐performance liquid chromatography/electrospray ionization triple quadrupole mass spectrometry (HPLC/MS/MS).

Results

The mycotoxins ochratoxin A (OTA) and fumonisins of the B‐ and C‐series (FB1, FB2, FB3, FB4, FC1, FC2/3, and FC4) as well as partially hydrolyzed fumonisins (pHFB1, pHFB2, pHFB3, pHFC1, and pHFC2/3) could successfully be detected by MALDI‐MSI in mold‐infested foodstuffs. The toxins are distributed differently in the material: OTA is co‐localized with visible fungal spoilage while fumonisins could be detected throughout the whole sample.

Conclusions

This work shows the applicability of MALDI‐MSI to mycotoxin analysis. It has been demonstrated that the analyzed mycotoxins are differently distributed within moldy foodstuffs. These findings show the potential of MALDI‐MSI for the localization of these hazardous compounds in various plant tissues. Copyright © 2016 John Wiley & Sons, Ltd.
A Conceptual Framework for a Systems Thinking Approach to US Population Health
Authors: Kapp Julie M. , Simoes Eduardo J. , DeBiasi Anne , Kravet Steven J.
Published: September 2016

US health outcomes remain poorer than those of high‐income peer countries despite collective efforts directed at improving health and healthcare. Regarding population health, such collective impact efforts increasingly come from community‐based organizations, as federal budgets have been cut over the years. The Institute of Medicine recently identified core metrics to facilitate collective efforts and specified the Secretary of Health and Human Services as the position to lead the nation's efforts to improve the health of the population. However, integration across such a complex system requires a clear, deliberate systems approach. We adapt The Malcolm Baldrige Framework for Performance Excellence as a conceptual model with which to apply systems thinking to population health improvement. We offer specific recommendations necessary to build a national systems thinking approach towards improving the health of communities and populations if we hope to ameliorate the US health disadvantage. Copyright © 2016 The Authors Systems Research and Behavioral Science published by International Federation for Systems Research and John Wiley & Sons Ltd.
Performance‐based durability design, carbonation part 2 – Classification of concrete
Authors: von Greve‐Dierfeld Stefanie , Gehlen Christoph
Published: September 2016

At present, prescriptive regulations with regard to concrete cover and composition are applied to provide sufficient durability of reinforced concrete members under exposure conditions with different degrees of severity. In view of current knowledge on deterioration mechanisms and their modelling, it is planned to change from these deemed‐to‐satisfy specifications to a performance‐based design approach in future standards. In such specifications, concrete durability design is based on the statistically characterized performance of concrete, determined in standardized tests with respect to defined classes of concretes with similar performance.

This paper presents the results of a study in which concrete mixes were tested and analysed with respect to their carbonation resistance. Compositions with similar performance are grouped into carbonation resistance classes. These classes are described statistically and requirements for performance testing are given. In addition, composition requirements are introduced in order to determine concrete performance depending on mix composition prescriptively. Finally, an example is given for the assessment of concrete performance with regard to carbonation.

This work was carried out at the request of JWG under CEN TC 250/SC2 and CEN TC 104/SC1 as an input and starting point for the ongoing committee work to implement the methodology from the fib Model Code for Concrete Structures 2010 in the next generation (2021) of European concrete standards.
Bioelectromagnetics researches in Japan for human protection from electromagnetic field exposures
Authors: Taki Masao
Published: September 2016

Research works on bioelectromagnetics in Japan are reviewed with a focus on the efforts devoted to the issue of human protection from electromagnetic field (EMF) exposures. History of this issue in Japan is briefly reviewed first for all EMF spectra. Then research works on radiofrequency (RF) EMF are summarized in more detail. The RF studies reviewed are mainly conducted in the framework of research program by the Ministry of Internal Affairs and Communications (MIC) started in 1997. Because of this program, collaborations between biology/medicine and engineering have been promoted. The results consistently show no evidence against the safety of RF‐EMF within the exposure levels of internationally accepted guidelines. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Critical Thinking Instruction in English for Academic Purposes Writing Courses: A Dialectical Thinking Approach
Authors: Tanaka Jay , Gilliland Betsy
Published: September 2016

Critical thinking (CT) is usually taught as a list of practical skills for students to master. In this article, the authors argue that CT instruction should go beyond skills to engage students with issues of identifying their own biases and understanding multiple perspectives on issues. This explicit attention to one's own bias is essential for dealing with the issues of sociocentrism and egocentrism, which hinder expansive thought. This article presents students’ perspectives on an English for academic purposes writing course where they engaged in dialectical CT instruction, reading and writing responses to articles on topics with multiple perspectives. Interview data reveal that students viewed CT as new and valuable, but also challenging. Furthermore, although students also elaborated on the ways CT is culturally distinct from their home culture, they nevertheless recognized the value of it not only for their future academic purposes but also for their lives outside the classroom.
α‐Helical coiled‐coil peptide materials for biomedical applications
Authors: Wu Yaoying , Collier Joel H.
Published: September 2016

Self‐assembling coiled coils, which occur commonly in native proteins, have received significant interest for the design of new biomaterials‐based medical therapies. Considerable effort over recent years has led to a detailed understanding of the self‐assembly process of coiled coils, and a diverse collection of strategies have been developed for designing functional materials using this motif. The ability to engineer the interface between coiled coils allows one to achieve variously connected components, leading to precisely defined structures such as nanofibers, nanotubes, nanoparticles, networks, gels, and combinations of these. Currently these materials are being developed for a range of biotechnological and medical applications, including drug delivery systems for controlled release, targeted nanomaterials, ‘drug‐free’ therapeutics, vaccine delivery systems, and others. WIREs Nanomed Nanobiotechnol 2017, 9:e1424. doi: 10.1002/wnan.1424

This article is categorized under:

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology

Biology-Inspired Nanomaterials > Peptide-Based Structures
Recent advances of using polyhydroxyalkanoate‐based nanovehicles as therapeutic delivery carriers
Authors: Li Zibiao , Loh Xian Jun
Published: September 2016

Polyhydroxyalkanoates (PHAs) are a class of diverse biodegradable polyesters that can be produced either by natural bioconversion process or by chemical synthesis via the ring‐opening polymerization of β‐lactones. Because of the excellent biodegradability and biocompatibility, the development of PHA‐based nanovehicles as therapeutic delivery carriers, including nanoparticles, micelles, liposomes, and vesicles, has received considerable attention in recent years, and these sophisticated materials have demonstrated significant impact on the drug bioavailability, better encapsulation, and less toxic properties of biodegradable polymers. In this review, the most recent advances of using PHA‐based nanovehicles as therapeutic delivery carriers are summarized with respect to different material types including intrinsic bulk PHA and functionalized PHA through biological and chemical approaches. The bio‐significance of using different carriers in the controlled and targeted delivery of hydrophobic drugs, proteins, vaccines, nucleic acids (DNA and siRNA), and biological macromolecules in cancer therapy is also discussed. WIREs Nanomed Nanobiotechnol 2017, 9:e1429. doi: 10.1002/wnan.1429

This article is categorized under:

Implantable Materials and Surgical Technologies > Nanomaterials and Implants

Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement
Assessing silicon deposits in Zilfi province, Saudi Arabia, using XRF and XRD techniques
Authors: Attaelmanan Atta G. , Suleman Nawal M. , El Agib Ibrahim A. , Al‐Sewaidan Hamed A
Published: September 2016

The aim of this project is to create a geochemical database of the Nafud Desert in Zilfi Province, which lies 260 km northwest of Riyadh, capital of Saudi Arabia, and assess its potential as a silicon mine. The area of study was surveyed during December 2012 collecting 21 geological samples from 7 places (Alsabla, Almatal, Shlwan, Alaaga, Jaway, Magra and Althuare).

Elemental composition was determined using X‐ray fluorescence spectrometry, while mineral content and crystallography analysis was performed using X‐ray diffraction.

Analysis results revealed that silicon was abundant in the area, in fairly homogeneous amounts. Silica was found in concentrations of around 93% per sampled mass, and silicon concentrations were around 42%, in the surface layers down to the depth of 40 cm.

Other elements (Al, K, Ca, Ti, Cr, Mn, Fe, Sr, Zr and Pd ) were present in very low concentrations, except for aluminium oxide, which was present in three areas (Jaway, Magra and Althuare) at concentrations around 5%, while Alsabla samples showed higher concentrations of CaO. Thus, according to the results, the Nafud Desert is a rich source of silicon that can be exploited very cheaply because of the presence of the raw material on the surface. Copyright © 2016 John Wiley & Sons, Ltd.
Phenols and Volatiles of Istarska Bjelica and Leccino Virgin Olive Oils Produced with Talc, NaCl and KCl as Processing Aids
Authors: Majetić Germek Valerija , Butinar Bojan , Pizzale Lorena , Bučar‐Miklavčič Milena , Conte Lanfranco S. , Koprivnjak Olivera
Published: September 2016

The effect of processing aids (2.5 % of talc, NaCl or KCl) on oil extractability and the profile of phenolic and volatile compounds of Istarska bjelica and Leccino oils was studied. Talc significantly increased extractability in both cultivars, while salts increased extractability in Leccino cv. In the laboratory extracted oils, phenols were determined by a RP‐HPLC–DAD method, whereas volatiles were determined by SPME/GC–MS. Talc addition significantly decreased hydroxytyrosol and increased ligstroside derivatives in produced oils, but did not affect the total phenol content. Among volatile compounds, only Z‐2‐penten‐1‐ol in Leccino and 1‐pentene‐3‐one in Istarska bjelica oils significantly increased by talc addition. Salts improved transfer of most individual phenols into oil, particularly oleuropein derivatives, and increased C6 aldehydes and C5 volatiles in Leccino oils. NaCl exerted a stronger effect in increasing individual phenols and volatiles than KCl.
Gravity-driven 1-D consolidation of cemented paste backfill in 3-m-high columns
Authors: Belem Tikou , El Aatar Omar , Bussière Bruno , Benzaazoua Mostafa
Published: September 2016

This paper investigates and simulates the effect of underground placement conditions of cemented paste backfill (CPB) on the evolution of its physical and mechanical properties. Experimental setups that consist of PVC+Makrolon®GP polycarbonate sheet columns, each 3 m high, were built and filled with CPB at two different backfill plants. These setups allow simulating undrained (UD), partial lateral drainage (PLD) and full lateral drainage (FLD) conditions and the measurement of resulting self-weight consolidation settlement of CPB. The results show that maximum drainage water percentages of 15 and 8 % of the CPB total initial water were observed for the FLD and the PLD columns. The results also suggest that in situ backfilled stopes behave in a similar way to that of FLD or PLD conditions.
Anal incontinence and fecal urgency following vaginal delivery with episiotomy among primiparous patients
Authors: Rusavy Zdenek , Karbanova Jaroslava , Jansova Magdalena , Kalis Vladimir
Published: September 2016

Objective

To investigate anal incontinence following mediolateral or lateral episiotomy during a first vaginal delivery.

Methods

The present prospective follow‐up study enrolled primiparous patients who underwent vaginal delivery including mediolateral or lateral episiotomy between April 1, 2010 and March 31, 2012. Participants completed interviews before delivery, and were given anal‐incontinence questionnaires to be returned for analysis at 3 months and 6 months postpartum. Anal incontinence was defined as a St Mark's incontinence score above four and individual anal‐incontinence components were analyzed separately; results were compared between the two episiotomy techniques.

Results

Questionnaires were returned by 300 and 366 patients who underwent mediolateral and lateral episiotomies, respectively; baseline characteristics were similar. Anal incontinence at 3 months and 6 months was recorded among 21 (7.0%) and 9 (3.0%) patients who underwent mediolateral and 27 (7.4%) and 20 (5.5%) who underwent lateral episiotomy, respectively. The study was underpowered to confirm equivalence between the groups; however, no statistically significant differences were observed in the rates of anal incontinence, flatus, solid or liquid incontinence, and de novo incontinence. Fecal urgency (P = 0.017) and de novo fecal urgency (P = 0.008) were more prevalent among patients who underwent lateral episiotomies at 6 months.

Conclusion

Anal incontinence was comparable between primiparous patients who underwent mediolateral or lateral episiotomy. The association between lateral episiotomy and fecal urgency merits further scientific interest.
Short stature in men is associated with subclinical peripheral arterial disease
Authors: Heikkilä Arto , Venermo Maarit , Kautiainen Hannu , Aarnio Pertti , Korhonen Päivi
Published: September 2016

Abstract. Background: Peripheral arterial disease (PAD) affects approximately 202 million individuals around the world and is associated with a high risk of myocardial infarction, stroke and death. Although there is a clear inverse association between adult height and the risk of cardiovascular disease, little is known about the relationship between height and PAD. The aim of our study was to assess the relationship between subclinical PAD and height. Patients and methods: In a cross-sectional cardiovascular risk factor study in southwestern Finland, ankle brachial index (ABI) and other risk factors were measured from a total of 972 cardiovascular risk subjects derived from the general population. None of them had previously diagnosed diabetes, cardiovascular or renal disease or intermittent claudication. Subjects with an ABI ≤ 0.90 were categorized as having subclinical PAD. Results: The average age of the study subjects was 58.1 ± 6.7 years for men and 58.8 ± 6.9 years for women. The prevalence of subclinical PAD was 5 % (95 % CI 3 % − 7 %) (23/455) among men and 5 % (95 % CI 3 %−7 %) (26/517) among women. The mean ABI among men and women was 1.09 ± 0.12 and 1.08 ± 0.12, respectively. In men, there was an inverse association between height and the prevalence of subclinical PAD (p < 0.001) along with a positive association between height and ABI values (p < 0.001). In a multivariate model, height, age and current smoking status remained independent factors that were associated with subclinical PAD in men, whereas in women, only pulse pressure was associated with subclinical PAD. Conclusions: Short stature in men is associated with subclinical PAD and lower ABI values.
Transarterial embolization of peripheral arteriovenous malformations with ethylenevinyl alcohol copolymer - feasibility, technical outcomes, and clinical outcomes
Authors: De Beule Tom , Vranckx Jan , Verhamme Peter , Labarque Veerle , Morren Marie-Anne , Fourneau Inge , Maleux Geert
Published: September 2016

Abstract. Background: The technical and clinical outcomes of catheter-directed embolization for peripheral arteriovenous malformations (AVM) using Onyx® (ethylene-vinyl alcohol copolymer) are not well documented. The purpose of this study was to retrospectively assess the safety, technical outcomes and clinical outcomes of catheter-directed Onyx® embolisation for the treatment of symptomatic peripheral AVMs. Patients and methods: Demographics, (pre-)interventional clinical and radiological data were assessed. Follow-up was based on hospital medical records and telephone calls to the patients’ general practitioners. Radiological success was defined as complete angiographic eradication of the peripheral AVM nidus. Clinical success was defined as major clinical improvement or complete disappearance of the initial symptoms. Results: 25 procedures were performed in 22 patients. The principal indications for treatment were pain (n = 10), limb swelling (n = 6), recurrent bleeding (n = 2), tinnitus (n = 3), and exertional dyspnoea (n = 1). Complete radiological success was obtained in eight patients (36 %); near-complete eradication of the nidus was achieved in the remaining 14 patients. Adjunctive embolic agents were used in nine patients (41 %). Clinical success was observed in 18 patients (82%). Major complications were reported in two patients (9 %). During follow-up, seven patients (32 %) presented with symptom recurrence, which required additional therapy in three patients. Conclusions: Catheter-directed embolisation of peripheral AVMs with Onyx® resulted in major clinical improvement or complete disappearance of symptoms in the vast majority of patients, although complete angiographic exclusion of the AVMs occurred in only a minority of patients.
Comparison of temporary abdominal aortic occlusion with internal iliac artery occlusion for patients with placenta accreta – a non-randomised prospective study
Authors: Wang Yan-Li , Duan Xu-Hua , Han Xin-Wei , Wang Ling , Zhao Xian-Lan , Chen Zhi-Min , Chu Qin-Jun , Zhang Wei
Published: September 2016

Abstract. Background: To compare the efficacy of temporary abdominal aortic occlusion with internal iliac artery occlusion for the management of placenta accreta. Patients and methods: 105 patients with placenta accreta were selected for treatment with temporary abdominal aortic occlusion (n = 57, group A) or bilateral iliac artery occlusion (n = 48, group B). Temporary abdominal aortic and internal iliac artery balloon occlusions were performed during caesarean sections. Data regarding the clinical success, blood loss, blood transfusion, balloon insertion time, fluoroscopy time, balloon occlusion time, foetal radiation dose, and complications were collected. Results: Temporary abdominal aortic occlusion and bilateral internal iliac artery occlusion were technically successful in all patients. The amount of blood loss (P < 0.001), amount of blood transfusion (P < 0.001), balloon insertion time (P < 0.001), foetal radiation dose (P < 0.001) and fluoroscopy time (P < 0.01) in group A were significantly lower than those of patients in group B. No marked differences were found between these 2 groups with respect to age, mean postoperative hospital stay, balloon occlusion time, and Apgar score (p > 0.05). Conclusions: Temporary abdominal aortic balloon occlusion resulted in better clinical outcomes with less blood loss, blood transfusion, balloon insertion time, fluoroscopy time and foetal radiation dose than those in bilateral internal iliac balloon occlusion.
Applications of stable, nonradioactive isotope tracers in in vivo human metabolic research
Authors: Kim Il-Young , Suh Sang-Hoon , Lee In-Kyu , Wolfe Robert R
Published: September 2016

The human body is in a constant state of turnover, that is, being synthesized, broken down and/or converted to different compounds. The dynamic nature of in vivo kinetics of human metabolism at rest and in stressed conditions such as exercise and pathophysiological conditions such as diabetes and cancer can be quantitatively assessed with stable, nonradioactive isotope tracers in conjunction with gas or liquid chromatography mass spectrometry and modeling. Although measurements of metabolite concentrations have been useful as general indicators of one’s health status, critical information on in vivo kinetics of metabolites such as rates of production, appearance or disappearance of metabolites are not provided. Over the past decades, stable, nonradioactive isotope tracers have been used to provide information on dynamics of specific metabolites. Stable isotope tracers can be used in conjunction with molecular and cellular biology tools, thereby providing an in-depth dynamic assessment of metabolic changes, as well as simultaneous investigation of the molecular basis for the observed kinetic responses. In this review, we will introduce basic principles of stable isotope methodology for tracing in vivo kinetics of human or animal metabolism with examples of quantifying certain aspects of in vivo kinetics of carbohydrate, lipid and protein metabolism.
Limited clonal relatedness between gut IgA plasma cells and memory B cells after oral immunization
Authors: Bemark Mats , Hazanov Helena , Strömberg Anneli , Komban Rathan , Holmqvist Joel , Köster Sofia , Mattsson Johan , Sikora Per , Mehr Ramit , Lycke Nils Y.
Published: September 2016

Understanding how memory B cells are induced and relate to long-lived plasma cells is important for vaccine development. Immunity to oral vaccines has been considered short-lived because of a poor ability to develop IgA B-cell memory. Here we demonstrate that long-lived mucosal IgA memory is readily achieved by oral but not systemic immunization in mouse models with NP hapten conjugated with cholera toxin and transfer of B1-8high/GFP+NP-specific B cells. Unexpectedly, memory B cells are poorly related to long-lived plasma cells and less affinity-matured. They are α4β7-integrin+CD73+PD-L2+CD80+and at systemic sites mostly IgM+, while 80% are IgA+in Peyer’s patches. On reactivation, most memory B cells in Peyer’s patches are GL7−, but expand in germinal centres and acquire higher affinity and more mutations, demonstrating strong clonal selection. CCR9 expression is found only in Peyer’s patches and appears critical for gut homing. Thus, gut mucosal memory possesses unique features not seen after systemic immunization.
Opportunities for biodiversity gains under the world’s largest reforestation programme
Authors: Hua Fangyuan , Wang Xiaoyang , Zheng Xinlei , Fisher Brendan , Wang Lin , Zhu Jianguo , Tang Ya , Yu Douglas W. , Wilcove David S.
Published: September 2016

Reforestation is a critical means of addressing the environmental and social problems of deforestation. China’s Grain-for-Green Program (GFGP) is the world’s largest reforestation scheme. Here we provide the first nationwide assessment of the tree composition of GFGP forests and the first combined ecological and economic study aimed at understanding GFGP’s biodiversity implications. Across China, GFGP forests are overwhelmingly monocultures or compositionally simple mixed forests. Focusing on birds and bees in Sichuan Province, we find that GFGP reforestation results in modest gains (via mixed forest) and losses (via monocultures) of bird diversity, along with major losses of bee diversity. Moreover, all current modes of GFGP reforestation fall short of restoring biodiversity to levels approximating native forests. However, even within existing modes of reforestation, GFGP can achieve greater biodiversity gains by promoting mixed forests over monocultures; doing so is unlikely to entail major opportunity costs or pose unforeseen economic risks to households.
LECT2 drives haematopoietic stem cell expansion and mobilization via regulating the macrophages and osteolineage cells
Authors: Lu Xin-Jiang , Chen Qiang , Rong Ye-Jing , Yang Guan-Jun , Li Chang-Hong , Xu Ning-Yi , Yu Chao-Hui , Wang Hui-Ying , Zhang Shun , Shi Yu-Hong , Chen Jiong
Published: September 2016

Haematopoietic stem cells (HSCs) can differentiate into cells of all lineages in the blood. However, the mechanisms by which cytokines in the blood affect HSC homeostasis remain largely unknown. Here we show that leukocyte cell-derived chemotaxin 2 (LECT2), a multifunctional cytokine, induces HSC expansion and mobilization. Recombinant LECT2 administration results in HSC expansion in the bone marrow and mobilization to the blood via CD209a. The effect of LECT2 on HSCs is reduced after specific depletion of macrophages or reduction of osteolineage cells. LECT2 treatment reduces the tumour necrosis factor (TNF) expression in macrophages and osteolineage cells. In TNF knockout mice, the effect of LECT2 on HSCs is reduced. Moreover, LECT2 induces HSC mobilization in irradiated mice, while granulocyte colony-stimulating factor does not. Our results illustrate that LECT2 is an extramedullar cytokine that contributes to HSC homeostasis and may be useful to induce HSC mobilization.
Colossal Seebeck effect enhanced by quasi-ballistic phonons dragging massive electrons in FeSb2
Authors: Takahashi H. , Okazaki R. , Ishiwata S. , Taniguchi H. , Okutani A. , Hagiwara M. , Terasaki I.
Published: September 2016

Phonon transport is an essential property of thermoelectric materials. Although the phonon carries heat, which reduces the thermoelectric efficiency, it contributes positively to the Seebeck coefficient S through the phonon-drag effect, as typified by the high-purity semiconductors, which show fairly large S at cryogenic temperatures. Although such a large S is attractive in terms of Peltier cooling, a clear guiding principle for designing thermoelectric materials enriched by the phonon-drag effect remains to be established. Here we demonstrate that a correlated semiconductor, FeSb2, is a promising thermoelectric material featuring quasi-ballistic phonons dragging d electrons with large effective mass. By changing the sample size within the sub-millimetre order for high-purity single crystals, we succeed in substantially increasing S to as much as −27 mV K−1 at low temperatures. Our results exemplify a strategy for exploring phonon-drag-based thermoelectric materials, the performance of which can be maximized by combining heavy electrons with ballistic phonons.
Genetic linkage of distinct adaptive traits in sympatrically speciating crater lake cichlid fish
Authors: Fruciano Carmelo , Franchini Paolo , Kovacova Viera , Elmer Kathryn R. , Henning Frederico , Meyer Axel
Published: September 2016

Our understanding of how biological diversity arises is limited, especially in the case of speciation in the face of gene flow. Here we investigate the genomic basis of adaptive traits, focusing on a sympatrically diverging species pair of crater lake cichlid fishes. We identify the main quantitative trait loci (QTL) for two eco-morphological traits: body shape and pharyngeal jaw morphology. These traits diverge in parallel between benthic and limnetic species in the repeated adaptive radiations of this and other fish lineages. Remarkably, a single chromosomal region contains the highest effect size QTL for both traits. Transcriptomic data show that the QTL regions contain genes putatively under selection. Independent population genomic data corroborate QTL regions as areas of high differentiation between the sympatric sister species. Our results provide empirical support for current theoretical models that emphasize the importance of genetic linkage and pleiotropy in facilitating rapid divergence in sympatry.
Longitudinal assessment of neuronal 3D genomes in mouse prefrontal cortex
Authors: Mitchell Amanda C. , Javidfar Behnam , Bicks Lucy K. , Neve Rachael , Garbett Krassimira , Lander Sharon S. , Mirnics Karoly , Morishita Hirofumi , Wood Marcelo A. , Jiang Yan , Gaisler-Salomon Inna , Akbarian Schahram
Published: September 2016

Neuronal epigenomes, including chromosomal loopings moving distal cis-regulatory elements into proximity of target genes, could serve as molecular proxy linking present-day-behaviour to past exposures. However, longitudinal assessment of chromatin state is challenging, because conventional chromosome conformation capture assays essentially provide single snapshots at a given time point, thus reflecting genome organization at the time of brain harvest and therefore are non-informative about the past. Here we introduce ‘NeuroDam’ to assess epigenome status retrospectively. Short-term expression of the bacterial DNA adenine methyltransferase Dam, tethered to the Gad1 gene promoter in mouse prefrontal cortex neurons, results in stable GmethylATC tags at Gad1-bound chromosomal contacts. We show by NeuroDam that mice with defective cognition 4 months after pharmacological NMDA receptor blockade already were affected by disrupted chromosomal conformations shortly after drug exposure. Retrospective profiling of neuronal epigenomes is likely to illuminate epigenetic determinants of normal and diseased brain development in longitudinal context.
Socio-economic factors, gender and smoking as determinants of COPD in a low-income country of sub-Saharan Africa: FRESH AIR Uganda
Authors: van Gemert Frederik , Chavannes Niels , Kirenga Bruce , Jones Rupert , Williams Sian , Tsiligianni Ioanna , Vonk Judith , Kocks Janwillem , de Jong Corina , van der Molen Thys
Published: September 2016

In Uganda, biomass smoke seems to be the largest risk factor for the development of COPD, but socio-economic factors and gender may have a role. Therefore, more in-depth research is needed to understand the risk factors. The aim of this study was to investigate the impact of socio-economic factors and gender differences on the COPD prevalence in Uganda. The population comprised 588 randomly selected participants (>30 years) who previously completed the FRESH AIR Uganda study. In this post hoc analysis, the impact of several socio-economic characteristics, gender and smoking on the prevalence of COPD was assessed using a logistic regression model. The main risk factors associated with COPD were non-Bantu ethnicity (odds ratio (OR) 1.73, 95% confidence interval (CI) 1.06–2.82, P=0.030), biomass fuel use for heating (OR 1.76, 95% CI 1.03–3.00, P=0.038), former smoker (OR 1.87, 95% CI 0.97–3.60, P=0.063) and being unmarried (OR 0.087, 95% CI 0.93–2.95, P=0.087). A substantial difference in the prevalence of COPD was seen between the two ethnic groups: non-Bantu 20% and Bantu 12.9%. Additional analysis between these two groups showed significant differences in socio-economic circumstances: non-Bantu people smoked more (57.7% vs 10.7%), lived in tobacco-growing areas (72% vs 14.8%) and were less educated (28.5% vs 12.9% had no education). With regard to gender, men with COPD were unmarried (OR 3.09, 95% CI 1.25–7.61, P=0.015) and used more biomass fuel for heating (OR 2.15, 95% CI 1.02–4.54, P=0.045), and women with COPD were former smokers (OR 3.35, 95% CI 1.22–9.22, P=0.019). Only a few socio-economic factors (i.e., smoking, biomass fuel use for heating, marital status and non-Bantu ethnicity) have been found to be associated with COPD. This applied for gender differences as well (i.e., for men, marital status and biomass fuel for heating, and for women being a former smoker). More research is needed to clarify the complexity of the different risk factors.
Characterizing the International Migration Barriers with a Probabilistic Multilateral Migration Model
Authors: Li Xiaomeng , Xu Hongzhong , Chen Jiawei , Chen Qinghua , Zhang Jiang , Di Zengru
Published: September 2016

Human migration is responsible for forming modern civilization and has had an important influence on the development of various countries. There are many issues worth researching, and “the reason to move” is the most basic one. The concept of migration cost in the classical self-selection theory, which was introduced by Roy and Borjas, is useful. However, migration cost cannot address global migration because of the limitations of deterministic and bilateral choice. Following the idea of migration cost, this paper developed a new probabilistic multilateral migration model by introducing the Boltzmann factor from statistical physics. After characterizing the underlying mechanism or driving force of human mobility, we reveal some interesting facts that have provided a deeper understanding of international migration, such as the negative correlation between migration costs for emigrants and immigrants and a global classification with clear regional and economic characteristics, based on clustering of migration cost vectors. In addition, we deconstruct the migration barriers using regression analysis and find that the influencing factors are complicated but can be partly (12.5%) described by several macro indexes, such as the GDP growth of the destination country, the GNI per capita and the HDI of both the source and destination countries.
Circulating Biomarkers of Immune Activation, Oxidative Stress and Inflammation Characterize Severe Canine Visceral Leishmaniasis
Authors: Solcà Manuela S. , Andrade Bruno B. , Abbehusen Melissa Moura Costa , Teixeira Clarissa R. , Khouri Ricardo , Valenzuela Jesus G. , Kamhawi Shaden , Bozza Patrícia Torres , Fraga Deborah Bittencourt Mothé , Borges Valeria Matos , Veras Patrícia Sampaio Tavares , Brodskyn Claudia Ida
Published: September 2016

Clinical manifestations in canine visceral leishmaniasis (CVL) have not been clearly associated with immunological status or disease progression. We simultaneously assessed biomarkers of inflammation, immune activation, oxidative stress, and anti-sand fly saliva IgG concentrations in dog sera with different clinical manifestations to characterize a biosignature associated with CVL severity. In a cross-sectional exploratory study, a random population of 70 dogs from an endemic area in Brazil was classified according to CVL clinical severity and parasitological evaluation. A panel of biomarkers and anti–sand fly saliva IgG were measured in canine sera. Assessment of protein expression of profile biomarkers identified a distinct biosignature that could cluster separately animal groups with different clinical scores. Increasing severity scores were associated with a gradual decrease of LTB4 and PGE2, and a gradual increase in CXCL1 and CCL2. Discriminant analyses revealed that combined assessment of LTB4, PGE2 and CXCL1 was able to distinguish dogs with different clinical scores. Dogs with the highest clinical score values also exhibited high parasite loads and higher concentrations of anti-saliva antibodies. Our findings suggest CVL clinical severity is tightly associated with a distinct inflammatory profile hallmarked by a differential expression of circulating eicosanoids and chemokines.
Smad4 suppresses the tumorigenesis and aggressiveness of neuroblastoma through repressing the expression of heparanase
Authors: Qu Hongxia , Zheng Liduan , Jiao Wanju , Mei Hong , Li Dan , Song Huajie , Fang Erhu , Wang Xiaojing , Li Shiwang , Huang Kai , Tong Qiangsong
Published: September 2016

Heparanase (HPSE) is the only endo-β-D-glucuronidase that is correlated with the progression of neuroblastoma (NB), the most common extracranial malignancy in childhood. However, the mechanisms underlying HPSE expression in NB still remain largely unknown. Herein, through analyzing cis-regulatory elements and mining public microarray datasets, we identified SMAD family member 4 (Smad4) as a crucial transcription regulator of HPSE in NB. We demonstrated that Smad4 repressed the HPSE expression at the transcriptional levels in NB cells. Mechanistically, Smad4 suppressed the HPSE expression through directly binding to its promoter and repressing the lymphoid enhancer binding factor 1 (LEF1)-facilitated transcription of HPSE via physical interaction. Gain- and loss-of-function studies demonstrated that Smad4 inhibited the growth, invasion, metastasis, and angiogenesis of NB cells in vitro and in vivo. Restoration of HPSE expression prevented the NB cells from changes in these biological features induced by Smad4. In clinical NB specimens, Smad4 was under-expressed and inversely correlated with HPSE levels, while LEF1 was highly expressed and positively correlated with HPSE expression. Patients with high Smad4 expression, low LEF1 or HPSE levels had greater survival probability. These results demonstrate that Smad4 suppresses the tumorigenesis and aggressiveness of NB through repressing the HPSE expression.
Genome-wide identification and comparison of legume MLO gene family
Authors: Rispail Nicolas , Rubiales Diego
Published: September 2016

MLO proteins are highly conserved proteins with seven trans-membrane domains. Specific MLO genes have been linked to plant disease susceptibility. Others are involved in plant reproduction and in root thigmomorphogenesis. Functions of the remaining MLOs are still unknown. Here we performed a genome-wide survey of the MLO family in eight legume species from different clades of the Papillionoideae sub-family. A total of 118 MLO sequences were identified and characterized. Their deduced protein sequences shared the characteristics of MLO proteins. The total number of MLO genes per legume species varied from 13 to 20 depending on the species. Legume MLOs were evenly distributed over their genomes and tended to localize within syntenic blocks conserved across legume genomes. Phylogenetic analysis indicated that these sequences clustered in seven well-defined clades. Comparison of MLO protein sequences revealed 34 clade-specific motifs in the variable regions of the proteins. Comparative analyses of the MLO family between legume species also uncovered several evolutionary differences between the tropical legume species from the Phaseoloid clades and the other legume species. Altogether, this study provides interesting new features on the evolution of the MLO family. It also provides valuable clues to identify additional MLO genes from non-sequenced species.
One-year Outcomes of Pachymetry and Epithelium Thicknesses after Accelerated (45 mW/cm2) Transepithelial Corneal Collagen Cross-linking for Keratoconus Patients
Authors: Zhang Xiaoyu , Sun Ling , Chen Yingjun , Li Meiyan , Tian Mi , Zhou Xingtao
Published: September 2016

The thickness of corneal pachymetry and the epithelium after accelerated (45 mW/cm2) transepithelial corneal collagen cross-linking (CXL) for keratoconus were assessed in this prospective case series study. Twenty-eight patients were treated for keratoconus. The mean Kmax was 56.18 ± 7.90. The thinnest point, as assessed by optical coherence tomography (OCT), was 443.18 ± 39.75 μm. Accelerated transepithelial CXL was performed, and corrected distance visual acuity (CDVA), corneal topography, and OCT were recorded at 1 week postoperatively as well as at 1, 3, 6, and 12 months. The surgery was uneventful in all eyes. Postoperative epithelial edema was observed and faded in 3 days. The postoperative Kmax was 54.56 ± 8.81, 55.78 ± 8.11, 56.37 ± 8.71, 55.80 ± 7.92, and 55.47 ± 8.24 at 1 week, 1 month, 3 months, 6 months, and 12 months, respectively (all, P > 0.05). The thinnest postoperative corneal point, 439.04 ± 44.99 μm, was observed at 12 months (P = 0.109). The epithelial thickness decreased during the first postoperative week then showed a gradual recovery. Postoperative pachymetry thickness showed no significant changes for up to 12 months. Postoperative epithelial thickness decreased temporarily, then stabilized at month 12. Accelerated transepithelial CXL was shown to be effective and safe for the treatment of keratoconus.
On the mobility, membrane location and functionality of mechanosensitive channels in Escherichia coli
Authors: van den Berg Jonas , Galbiati Heloisa , Rasmussen Akiko , Miller Samantha , Poolman Bert
Published: September 2016

Bacterial mechanosensitive channels protect cells from structural damage during hypoosmotic shock. MscS, MscL and MscK are the most abundant channels in E. coli and arguably the most important ones in osmoprotection. By combining physiological assays with quantitative photo-activated localization microscopy (qPALM), we find an almost linear relationship between channel abundance and cell survival. A minimum of 100 MscL (or MscS) channels is needed for protection when a single type of channel is expressed. Under native-like conditions MscL, MscS as well as MscK distribute homogeneously over the cytoplasmic membrane and the lateral diffusion of the channels is in accordance with their relative protein mass. However, we observe cluster formation and a reduced mobility of MscL when the majority of the subunits of the pentameric channel contain the fluorescent mEos3.2 protein. These data provide new insights into the quantitative biology of mechanosensitive channels and emphasizes the need for care in analysing protein complexes even when the fluorescent tag has been optimized for monomeric behaviour.
Biogeography and Adaptive evolution of Streptomyces Strains from saline environments
Authors: Zhao Fei , Qin Yu-Hua , Zheng Xin , Zhao Hong-Wei , Chai Dong-Yan , Li Wei , Pu Ming-Xiang , Zuo Xing-Sheng , Qian Wen , Ni Ping , Zhang Yong , Mei Han , He Song-Tao
Published: September 2016

The genus Streptomyces is a widespread genus within the phylum Actinobacteria and has been isolated from various environments worldwide. However, little is known about whether biogeography affects distributional pattern of Streptomyces in salty environments. Such information is essential for understanding the ecology of Streptomyces. Here we analyzed four house-keeping genes (16S rRNA, rpoB, recA and atpD) and salty-tolerance related genes (ectA-ectD) of 38 Streptomyces strains isolated from saline environments in Yunnan and Xinjiang Provinces of western China. The obtained Streptomyces strains were classified into three operational taxonomic units, each comprising habitat-specific geno- and ecotype STs. In combination with expressional variations of salty-tolerance related genes, the statistical analyses showed that spatial distance and environmental factors substantially influenced Streptomyces distribution in saline environments: the former had stronger influence at large spatial scales (>700 km), whereas the latter was influential at large (>700 km) and small spatial scales (<700 km). Plus, the quantitative analyses of salty-tolerence related genes (ectA-D) indicated that Streptomyces strains from salt lakes have higher expression of ectA-D genes and could accumulate larger quantities of ectoine and hydroxyectoine than strains from salt mines, which could help them resist to salinity in the hypersaline environments.