bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnitude of Species Diversity Effect on Aboveground Plant Biomass Increases Through Successional Time of Abandoned Farmlands on the Eastern Tibetan Plateau of China
Authors: Li Wenjin , Li Jinhua , Liu Shuangshuang , Zhang Rulan , Qi Wei , Zhang Renyi , Knops Johannes M. H. , Lu Junfeng 
Published: September 2016

AbstractRecent empirical and theoretical studies have shown that magnitude and direction of biodiversity effects on ecosystem functioning can shifts over time. Here, we used species richness and plant abundance (total individual plant stem density) as proxies for species diversity and aboveground biomass for productivity. We used an analytical approach combining both chronosequence and 6 year of vegetation monitoring in a subalpine ecosystem as a model system to assess temporal species richness–abundance–aboveground biomass relationships at different successional stages and spatial scales. We observed that both species richness and plant aboveground biomass increased rapidly early in succession after land abandonment, then after 10 years of abandonment reached a steady state. We found that the relationship between species richness and plant abundance with aboveground biomass was strengthening over successional time. In all successional stages, species richness had stronger positive effects as compared with plant abundance on plant aboveground biomass. Species richness was linearly correlated with aboveground biomass, whereas plant abundance showed a humped‐back relationship with aboveground biomass across all successional stages. Our results showed an increase in the effect of plant diversity over time, and a combination of both plant species richness and abundance is correlated with plant productivity throughout successional time, knowledge that maybe important to managing ecological restoration and conservation. Copyright © 2016 John Wiley & Sons, Ltd.
Spatiotemporal Heterogeneity of Soil Available Nitrogen During Crop Growth Stages on Mollisol Slopes of Northeast China
Authors: Zhang Shaoliang , Huang Jing , Wang Yao , Shen Qingsong , Mu Linlin , Liu Zhihua 
Published: September 2016

AbstractSpatiotemporal heterogeneity of soil available nitrogen (AN) (sum of NO3−–N and NH4+–N) is the essential basis for soil management and highly correlates to crop yield. Both geostatistical and traditional analyses were used to describe the spatiotemporal distribution of AN in the 0–20‐cm soil depth on typical Mollisol slopes (S1 and S2) in Northeast China. The concentration of NO3−–N dynamics at slope positions was typically opposite to NH4+–N. The peak values of AN typically moved from the summit of the slope to the bottom from spring to autumn and were mainly influenced by the content of NO3−–N (S1, 7·9–18·9 mg kg−1; S2, 1·2–103·6 mg kg−1), both of NO3−–N (S1, 3·9–8·3 mg kg−1; S2, 2·2–28·0 mg kg−1) and NH4+–N (S1, 21·4–30·5 mg kg−1; S2, 2·1–23·3 mg kg−1), and NH4+–N (S1, 10·5–28·9 mg kg−1; S2, 5·0–39·0 mg kg−1) in the seedling stage, vegetative growth stage, and reproductive growth stage, respectively. The spatial autocorrelation of AN was strong and was mainly influenced by structural factors during crop growth stages. This was mainly determined by soil erosion–deposition (SED) and soil temperature–moisture (STM) in the seedling stage; this was also mainly influenced by SED, STM, crop type, and crop growth in the vegetative growth stage and by early STM and early SED in the reproductive growth stage. Generally, the content of AN, NO3−–N, and NH4+–N on the whole slope was mainly determined by the early SED and local fertilizer application, while their spatiotemporal heterogeneity, especially the evenness, was mainly changed by SED, STM, crop growth, and crop types on the slope scale. In order to increase more crop yields, additional N fertilizer application on both the summit and the bottom during the vegetative growth stage and conservation tillage systems or additional soil amendments on the back slopes was necessary. Copyright © 2016 John Wiley & Sons, Ltd.
Room temperature operation of a deep etched buried heterostructure photonic crystal quantum cascade laser
Authors: Peretti Romain , Liverini Valeria , Süess Martin J. , Liang Yong , Vigneron Pierre‐ Baptiste , Wolf Johanna M. , Bonzon Christopher , Bismuto Alfredo , Metaferia Wondwosen , Balaji Manavaimaran , Lourdudoss Sebastian , Gini Emilio , Beck Mattias , Faist Jérome 
Published: September 2016

AbstractHigh power single mode quantum cascade lasers with a narrow far field are important for several applications including surgery or military countermeasure. Existing technologies suffer from drawbacks such as operation temperature and scalability. In this paper we introduce a fabrication approach that potentially solves simultaneously these remaining limitations. We demonstrate and characterize deep etched, buried photonic crystal quantum cascade lasers emitting around a wavelength of 8.5 μm. The active region was dry etched before being regrown with semi‐insulating Fe:InP. This fabrication strategy results in a refractive index contrast of 10% allowing good photonic mode control, and simultaneously provides good thermal extraction during operation. Single mode emission with narrow far field pattern and peak powers up to 0.88 W at 263 K were recorded from the facet of the photonic crystal laser, and lasing operation was maintained up to room temperature. The lasing modes emitted from square photonic crystal mesas with a side length of 550μm, were identified as slow Bloch photonic crystal modes by means of three‐dimensional photonic simulations and measurements.
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Transmitting boundary conditions for 1D peridynamics
Authors: Wang Linjuan , Chen Yongshuai , Xu Jifeng , Wang Jianxiang 
Published: September 2016

SummaryThe peridynamic theory reformulates the equations of continuum mechanics in terms of integro‐differential equations instead of partial differential equations. It is not straightforward to apply the available artificial boundary conditions for continua to peridynamic modeling. We therefore develop peridynamic transmitting boundary conditions (PTBCs) for 1D wave propagation. Differently from the previous method where the matching boundary condition is constructed for only one boundary material point, the PTBCs are established by considering the interaction and exchange of information between a group of boundary material points and another group of inner material points. The motion of the boundary material points is recursively constructed in terms of their locations and is determined through matching the peridynamic dispersion relation. The effectiveness of the PTBCs is examined by reflection analyses, numerical tests, and numerical convergent conditions. Furthermore, two‐way interfacial conditions are proposed. The PTBCs are then applied to simulations of wave propagation in a bar with a defect, a composite bar with interfaces, and a domain with a seismic source. All the analyses and applications demonstrate that the PTBCs can effectively remove undesired numerical reflections at artificial boundaries. The methodology may be applied to modeling of wave propagation by other nonlocal theories. Copyright © 2016 John Wiley & Sons, Ltd.
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

AbstractSelf‐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

RationaleThe “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.MethodsThe 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.ResultsWe 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.ConclusionsA 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

RationaleMycotoxins 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.MethodsVarious 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).ResultsThe 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.ConclusionsThis 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.
Performance‐based durability design, carbonation part 2 – Classification of concrete
Authors: von Greve‐Dierfeld Stefanie , Gehlen Christoph 
Published: September 2016

AbstractAt 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.
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.1424This 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.1429This 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

AbstractThe 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

AbstractThis 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

AbstractObjectiveTo investigate anal incontinence following mediolateral or lateral episiotomy during a first vaginal delivery.MethodsThe 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.ResultsQuestionnaires 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.ConclusionAnal incontinence was comparable between primiparous patients who underwent mediolateral or lateral episiotomy. The association between lateral episiotomy and fecal urgency merits further scientific interest.
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

AbstractThe 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.