bluuebunny/crossref_metadata_2025 huggingface dataset:
Explaining Social Disparities in Mathematical Achievement: The Role of Motivation
Authors: Kriegbaum Katharina , Spinath Birgit
Published: February 2016

This study examined the role of motivation as a mediator of the relationship between parents’ socio–economic status (SES) and children's standardized test achievement in math. We employed a one–year longitudinal approach using Programme for International Student Assessment (PISA) 2003 and a follow–up exam in 2004. The sample consisted of N = 6020 German students (mean age 15.5 years, SD = .55) who continued school after Grade 9 (PISA 2003) and were in Grade 10 at the time of PISA 2004. Children completed measures related to their parents’ SES, math–specific self–concept, task–specific and global self–efficacy, and interest, intelligence and mathematical competence. We found a small to moderate correlation between parents’ SES and children's achievement. All motivational constructs partially mediated the relationship between father's SES as well as a family index for SES (economic, social, and cultural status) and children's mathematical competence, but only math–specific self–concept and self–efficacy were significant mediators for mother's SES. Even when simultaneously considering the mediating effect of children's intelligence and prior achievement, the mediation effects of motivation remained significant. These results are important for our understanding of educational equality. Copyright © 2016 European Association of Personality Psychology
Sexuality‐related issues in borderline personality disorder: A comprehensive review
Authors: Frías Álvaro , Palma Carol , Farriols Núria , González Laura
Published: February 2016

Objective

Sexuality is somewhat neglected in clinical research on borderline personality disorder (BPD).

Method

We performed a systematic review from 1980 to November 2014 through PubMed and PsycINFO.

Results

Empirical evidence underscores that childhood sexual trauma may be considered a non‐specific risk factor for BPD. Furthermore, individuals with BPD also display higher sexual identity disturbances and homosexual relationships than non‐BPD individuals. Moreover, patients with BPD also exhibit higher sexual impulsivity than non‐BPD. In addition, sexual risk behaviours among individuals with BPD are related to increased rates of sexually transmitted diseases, unwanted pregnancies, rape and commercial sexual relationships, especially among drug abusers. Although psychotherapy is widely recommended for BPD, there has been little systematic research on the effect of these treatments with respect to co‐morbid post‐traumatic symptoms related to childhood sexual trauma.

Conclusions

Sexuality‐related issues represent a major clinical topic within this population. Findings are discussed concerning their methodological limitations and clinical implications. Copyright © 2016 John Wiley & Sons, Ltd.
Recent progress on cyclic polymers: Synthesis, bioproperties, and biomedical applications
Authors: Tu Xiao‐Yan , Liu Ming‐Zhu , Wei Hua
Published: February 2016

Polymer topologies exert a significant effect on its properties, and polymer nanostructures with advanced architectures, such as cyclic polymers, star‐shaped polymers, and hyperbranched polymers, are a promising class of materials with advantages over conventional linear counterparts. Cyclic polymers, due to the lack of polymer chain ends, have displayed intriguing physical and chemical properties. Such uniqueness has drawn considerable attention over the past decade. The current review focuses on the recent progress in the design and development of cyclic polymer with an emphasis on its synthesis and bio‐related properties and applications. Two primary synthetic strategies towards cyclic polymers, that is, ring‐expansion polymerization and ring‐closure reaction are summarized. The bioproperties and biomedical applications of cyclic polymers are then highlighted. In the end, the future directions of this rapidly developing research field are discussed. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1447–1458
Self‐consistent simulation of two‐dimensional electron gas characteristics of a novel (InxAl1–xN/AlN) MQWs/InN/GaN heterostructure
Authors: Li Wei , Wang Quan , Wang Cuimei , Yin Haibo , Yan Junda , Gong Jiamin , Li Baiquan , Wang Xiaoliang , Wang Zhanguo
Published: February 2016

In this paper, (InxAl1–xN/AlN) MQWs/InN/GaN heterostructure with a (InxAl1–xN/AlN) MQWs barrier layer and an InN channel layer is presented. The numerical calculations of 2DEG characteristics are made using a self‐consistent solution of the Schrödinger and Poisson equations. The influence of (InxAl1–xN/AlN) MQWs and InN layer on band diagrams, 2DEG sheet density and carrier confinement are studied. The results show that an InN insert layer can improve the carrier‐confinement ability without degrading the 2DEG sheet density in the heterostructure. The (InxAl1–xN/AlN) MQWs/InN/GaN heterostructure has both a larger 2DEG sheet density and better confinement of 2DEG than conventional InAlN/GaN and AlGaN/GaN heterojunctions. The 2DEG sheet density is as dramatically large as 3.85 × 1013 cm−2 with an AlN thickness of 1.5 nm, an In0.18Al0.82N thickness of 1.5 nm, an InN thickness of 0.5 nm, and pair number of 5. In addition, the influence of AlN thickness, InAlN thickness, indium content, and pair number on the 2DEG sheet density of the (InxAl1–xN/AlN) MQWs/InN/GaN heterostructure has been studied.
Integrated enhancement/depletion‐mode GaN MIS‐HEMTs for high‐speed mixed‐signal applications
Authors: Gao Tao , Xu Ruimin , Kong Yuechan , Zhou Jianjun , Zhang Kai , Kong Cen , Peng Daqing , Chen Tangsheng
Published: February 2016

Monolithically integrated enhancement/depletion (E/D)‐mode AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors (MIS‐HEMTs) are being developed for high‐speed mixed‐signal applications. Partially recessed gate combined with buffered gate insulator produce remarkably improved trade‐off between the threshold voltage (1.4 V) and current density (848 mA mm−1) in the E‐mode device. Record peak transconductances of 311 and 248 mA mm−1 are obtained for D‐ and E‐mode MIS‐HEMTs, respectively. A direct‐coupled FET logic (DCFL) 51‐stage ring oscillator implemented using the MIS‐HEMT technique is fabricated, which exhibits high‐speed performance with an oscillation frequency of 908 MHz and a high output voltage swing of 1.48 V.
Critical difference between optoelectronic properties of α‐ and β‐SnWO4 semiconductors: A DFT/HSE06 and experimental investigation
Authors: Harb Moussab , Ziani Ahmed , Takanabe Kazuhiro
Published: February 2016

The optoelectronic properties of β‐SnWO4 are investigated in details using experiments on thin film generated by rapid quenching and the first‐principles quantum calculations based on the density functional theory (DFT, including the perturbation approach DFPT) and employing the PBE and the range‐separated hybrid exchange–correlation HSE06 functionals. The obtained bandgap, optical absorption coefficient, dielectric constant, and charge‐carrier effective masses for β‐SnWO4 exhibit data irreconcilable with the reported values: e.g., a large and direct bandgap of 4.30 eV (UV‐responsive), inconsistent with the values in the literature (visible‐responsive). These properties obtained for β‐SnWO4 are distinctive from those for α‐SnWO4: an indirect bandgap of 1.52 eV with higher charge mobilities. These data of intrinsic stoichiometric materials suggest that the literature reported nonstoichiometric materials where defects significantly influence the optoelectronic properties.
Energetics and core structure of the undissociated basal screw dislocation in wurtzite GaN
Authors: Belabbas I. , Chen J. , Nouet G.
Published: February 2016

We have carried out computer atomistic simulations, based on Density Functional Theory, to investigate energetics and core structure of the undissociated basal screw dislocation in wurtzite GaN. Our calculations enabled us to establish the energetic hierarchy of two stable core configurations. The shuffle core configuration, which is formed by fully coordinated atoms, was demonstrated to be more energetically favorable than the glide configuration, which exhibits sp2‐like hybridization. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of QW growth temperature on the optical properties of blue and green InGaN/GaN QW structures
Authors: Hammersley Simon , Kappers Menno J. , Massabuau Fabien C.‐P. , Sahonta Suman‐Lata , Dawson Phil , Oliver Rachel A. , Humphreys Colin J.
Published: February 2016

In this paper we report on the impact that the quantum well growth temperature has on the internal quantum efficiency and carrier recombination dynamics of two sets of InGaN/GaN multiple quantum well samples, designed to emit at 460 and 530 nm, in which the indium content of the quantum wells within each sample set was maintained. Measurements of the internal quantum efficiency of each sample set showed a systematic variation, with quantum wells grown at a higher temperature exhibiting higher internal quantum efficiency and this variation was preserved at all excitation power densities. By investigating the carrier dynamics at both 10 K and 300 K we were able to attribute this change in internal quantum efficiency to a decrease in the non‐radiative recombination rate as the QW growth temperature was increased which we attribute to a decrease in incorporation of the point defects. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impact of interface traps on switching behavior of normally‐OFF AlGaN/GaN MOS‐HEMTs
Authors: Shi Yuanyuan , Zhou Qi , Jin Yang , Chen Bowen , Chen Wanjun , Huang Wei , Zhang Bo
Published: February 2016

In this paper, we report an experimental observation of the two‐stage turn‐on characteristic in normally‐OFF Al2O3/GaN metal‐oxide‐semiconductor high electron mobility transistors (MOS‐HEMTs) on Si substrate. The impact of oxide/GaN interface traps with different energy levels on the switching behavior of the device was extensively examined by simulation and verified by measurements. The interface traps at 0.4 eV below the bottom of the conduction band (Eit = EC‐0.4 eV) of GaN buffer with a density of Dit= 6.5×1012 cm‐2 was identified responsible for the observed two‐stage turn‐on characteristic. The weak Fermi‐level pinning (WFLP) induced by the dynamic electron filling of interface traps may hamper the electron from accumulating in the Al2O3/GaN MOS‐channel and then manifests a premature turn‐on during the switching‐on process. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth mode of nitride semiconductors on nano‐patterned sapphire substrates by molecular beam epitaxy
Authors: Song Bowen , Sun Haiding , Kao Chen‐Kai , Moustakas Theodore D.
Published: February 2016

In this paper we report on the growth mode by plasmaassisted MBE of nitride films on nano‐patterned sapphire substrates. Such substrates were fabricated using nano‐sphere and nano‐imprint lithographies, which led to cone‐and cylinder‐shaped patterns respectively. The data indicate that the pillars of the patterned substrate act a seeds for the subsequent growth and that the growth proceeds through the formation of a fully faceted pyramidal top surface. As the growth proceeds to more than 3 µm, the growth is dominated by the lateral growth of the top (0001) facets since the fluxes of the precursors on the inclined facets are lower. Eventually, these hexagonal (0001) facets coalesce leading to a continuous film with a smooth surface morphology.

This multifaceted growth mode at the initial stages has the potential of lateral expulsion of threading dislocation by the inclined facets leading to nitride pillars with minimum number of threading dislocations. Cathodoluminescence measurements indicate significant increase in the emission intensity from the films grown on the nanopatterned sapphire substrates, compared to the emission from the films grown on the un‐patterned sapphire substrates. This increase is partly due to improvements in light extraction and partly to the improved crystalline quality of the films. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence of high‐resistivity ZnTe crystals doped with gallium and indium
Authors: Seto Satoru , Suzuki Kazuhiko
Published: February 2016

We have measured photoluminescence spectra of high‐resistivity ZnTe crystals doped with gallium and indium in the wide energy range from near‐band‐edge energy to deep energy region up to 0.78 eV. In the near‐band‐edge energy, we detected a characteristic excitonic peak at 2.363 eV in both gallium and indium doped high resistivity ZnTe. By comparison with a similar PL peak observed in high resistivity CdTe, we identified the characteristic peak at 2.363 eV as emission from excitons bound to defects complex arising from a Zn vacancy and gallium or indium atoms (VZn‐2D). In lower energy range, a newly strong deep emission band near 1.0 eV has been observed for the first time in high‐resistivity ZnTe crystals. The intensity of the deep emission is two order magnitude stronger than that in undoped one. Furthermore, the intensity and peak position of the deep emission band are almost unchanged by Zn‐saturated anneal at 600‐680 °C. We specualte that this deep emission band is responsible for the high resistivity of ZnTe and prevent conversion of n‐type low resistivity. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystallographic and optical characterizations of Ag(Ga,Al)Te2 layers grown on c ‐plane sapphire substrates by closed space sublimation
Authors: Uruno Aya , Takeda Yuji , Inoue Tomohiro , Kobayashi Masakazu
Published: February 2016

Ag(Ga,Al)Te2 layers were grown by the closed space sublimation method on c ‐plane sapphire substrates. The source used was AgAlTe2/AgGaTe2 mixture or AgAlTe2/Ga2Te3 mixture. The crystallographic property of Ag(Ga,Al)Te2 layers was analyzed by X‐ray diffraction (XRD). XRD spectra of layers exhibited very strong 112 diffraction peaks regardless of the variation of the source material mixture. In addition to crystallographic characterizations, optical properties of the Ag(Ga,Al)Te2 layer were evaluated through transmittance measurements. The bandgap energy was decreased when the source mole ratio of Al to Ga was decreased. It was revealed that control regulation of x composition of Ag(Ga1‐x,Alx)Te2 was feasible by varying the source mole ratio Al/(Ga+Al). (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum confined Stark effect of polar and non‐polar ZnO/ZnMgO quantum wells grown by MBE
Authors: Abe Tomoki , Motoyama Tatsuya , Yamamoto Masaya , Yamamoto Atsushi , Iwagashita Shohei , Kasada Hirofumi , Ando Koshi , Ichino Kunio
Published: February 2016

We have investigated quantum confined Stark effects of polar (O‐polar) and non‐polar ZnO/ZnMgO quantum wells (QWs) by electroabsorption (EA) spectroscopy. The ZnO/ZnMgO QWs were grown by plasma assisted molecular beam epitaxy (PA‐MBE). The ZnO/ZnMgO QWs were grown on c‐plane sapphire for polar ZnO QWs, and on r‐plane sapphire for non‐polar ZnO QWs, respectively. The polar ZnO/ZnMgO QWs exhibited a blue‐shift of 20 meV in excitonic transition energy by applying external bias at room temperature. This blue‐shift is due to reverse quantum confined Stark effect (QCSE) in a piezo electric‐field induced QW structures of wurtzite ZnO/ZnMgO QWs with c‐axis orientation. We confirmed a large red‐shift of 29 meV for non‐polar ZnO/ZnMgO QWs. This energy shift is originated from normal QCSE in the flat potential QWs without built‐in piezo electric‐field. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin properties of localized hole and resident electron in ZnO epilayers
Authors: Kim Jungtaek , Puls J. , Sadofev S.
Published: February 2016

The spin dynamic of the hole localized inside the donor bound exciton (D0X) and donor electrons is studied in ZnO epilayer by time‐resolved optical orientation of the D0X photoluminescence and the absorption bleaching of the spin‐sensitive D0X transition, respectively. A D0X life time of 140 ps and hole spin relaxation time of 80 ps are extracted. The comparable times allows us for an effective pumping of the donor electron spin via circularly polarized excitation.

Long electron spin relaxation times in the 1 μs range are uncovered if the hyperfine interaction is suppressed by a proper longitudinal magnetic field B‖. A field strength of ≈2 mT is large enough to achieve that proving the extremely small Overhauser field BN acting on localized electrons. This is a direct result of the small abundance of magnetic nuclei interacting inside the small donor volume both specific for ZnO. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterisation of convective regimes over the British Isles
Authors: Flack David L. A. , Plant Robert S. , Gray Suzanne L. , Lean Humphrey W. , Keil Christian , Craig George C.
Published: February 2016

Convection‐permitting modelling has led to a step change in forecasting convective events. However, convection occurs within different regimes which exhibit different forecast behaviour. A convective adjustment timescale can be used to distinguish between these regimes and examine their associated predictability. The convective adjustment timescale is calculated from radiosonde ascents and found to be consistent with that derived from convection‐permitting model forecasts. The model‐derived convective adjustment timescale is then examined for three summers in the British Isles to determine characteristics of the convective regimes for this maritime region. Convection in the British Isles is predominantly in convective quasi‐equilibrium, with 85% of convection having a timescale less than or equal to 3 h. This percentage varies spatially with more non‐equilibrium events occurring in the south and southwest. The convective adjustment timescale exhibits a diurnal cycle over land. The non‐equilibrium regime occurs more frequently at mid‐range wind speeds and with winds from southerly to westerly sectors. Most non‐equilibrium convective events in the British Isles are initiated near large coastal orographic gradients or on the European continent. Thus, the convective adjustment timescale is greatest when the location being examined is immediately downstream of large orographic gradients and decreases with distance from the convective initiation region. The dominance of convective quasi‐equilibrium conditions over the British Isles argues for the use of large‐member ensembles in probabilistic forecasts for this region.
Atomic force microscopy study of ionomycin‐induced degranulation in RBL‐2H3 cells
Authors: Pi Jiang , Huang Lufen , Yang Fen , Jiang Jinhuan , Jin Hua , Liu Jianxin , Su Xiaohui , Wu Anguo , Cai Huaihong , Yang Peihui , Cai Jiye
Published: February 2016

Mast cell degranulation is the typical anaphylaxis process of mast cells associated with the release of cytokines, eicosanoids and their secretory granules, which play very important roles in the allergic inflammatory response of the human body upon anaphylactogen stimulation. The calcium ionophore ionomycin is widely used as a degranulation induction agent for mast cell degranulation studies. In the present work, ionomycin‐induced degranulation of RBL‐2H3 basophilic leukemia cell line cells was investigated in vitro by high resolution atomic force microscopy (AFM). Ionomycin, which could increase the intracellular free Ca2+ level and β‐Hexosaminidase release, was found to induce the formation of a kind of peculiar vesicles in the cytoplasm area of RBL‐2H3 cells. Those vesicles induced by ionomycin would desintegrate to release a larger amount of granules surrounding RBL‐2H3 cells by the controlling of F‐actin. These results provide the precise morphological information of ionomycin‐induced mast cell degranulation at nanoscale, which could benefit our understanding of ionomycin‐induced mast cell anaphylaxis model and also validate the applicability of AFM for the detection of allergic inflammatory response in mast cells. SCANNING 38:525–534, 2016. © 2016 Wiley Periodicals, Inc.
How Students View the Boundaries Between Their Science and Religious Education Concerning the Origins of Life and the Universe
Authors: BILLINGSLEY BERRY , BROCK RICHARD , TABER KEITH S. , RIGA FRAN
Published: February 2016

Internationally in secondary schools, lessons are typically taught by subject specialists, raising the question of how to accommodate teaching which bridges the sciences and humanities. This is the first study to look at how students make sense of the teaching they receive in two subjects (science and religious education [RE]) when one subject's curriculum explicitly refers to cross‐disciplinary study and the other does not. Interviews with 61 students in seven schools in England suggested that students perceive a permeable boundary between science and their learning in science lessons and also a permeable boundary between religion and their learning in RE lessons, yet perceive a firm boundary between science lessons and RE lessons. We concluded that it is unreasonable to expect students to transfer instruction about cross‐disciplinary perspectives across such impermeable subject boundaries. Finally, we consider the implications of these findings for the successful management of cross‐disciplinary education.
Pitch‐based steganography for Speex voice codec
Authors: Janicki Artur
Published: February 2016

This paper presents an improved version of a steganographic algorithm for IP telephony called HideF0. It is based on approximating the F0 parameter, which is responsible for conveying information about the pitch of the speech signal. The bits saved due to simplification of the pitch contour are used for the hidden transmission. In our experiments, the proposed method was applied to the narrowband Speex codec working in five different modes, with bitrates between 5,950 bps and 24,600 bps. We showed that HideF0 was able to create hidden channels with steganographic bandwidths of around 200 bps at the expense of a steganographic cost of between 0.5 and 0.7 MOS, depending on the Speex mode. Because of placing the approximation flag in the voice packet header, the improved version of the proposed algorithm yielded a significantly lower decrease in speech quality, when compared with the original version of HideF0. In addition, for low bitrates of the hidden channel (i.e., below ca. 50 bps) it was able to operate without introducing any steganographic cost. Copyright © 2016 John Wiley & Sons, Ltd.
A wavelet‐PCA method saves high mass resolution information in data treatment of SIMS molecular depth profiles
Authors: Tuccitto Nunzio , Zappalà Gabriella , Vitale Stefania , Torrisi Alberto , Licciardello Antonino
Published: February 2016

A detailed depth characterization of multilayered polymeric systems is a very attractive topic. Currently, the use of cluster primary ion beams in time‐of‐flight secondary ion mass spectrometry allows molecular depth profiling of organic and polymeric materials. Because typical raw data may contain thousands of peaks, the amount of information to manage grows rapidly and widely, so that data reduction techniques become indispensable in order to extract the most significant information from the given dataset. Here, we show how the wavelet‐based signal processing technique can be applied to the compression of the giant raw data acquired during time‐of‐flight secondary ion mass spectrometry molecular depth‐profiling experiments. We tested the approach on data acquired by analyzing a model sample consisting of polyelectrolyte‐based multilayers spin‐cast on silicon. Numerous wavelet mother functions and several compression levels were investigated. We propose some estimators of the filtering quality in order to find the highest ‘safe’ approximation value in terms of peaks area modification, signal to noise ratio, and mass resolution retention. The compression procedure allowed to obtain a dataset straightforwardly ‘manageable’ without any peak‐picking procedure or detailed peak integration. Moreover, we show that multivariate analysis, namely, principal component analysis, can be successfully combined to the results of the wavelet‐filtering, providing a simple and reliable method for extracting the relevant information from raw datasets. Copyright © 2016 John Wiley & Sons, Ltd.
Concise Review: When Colonies Are Not Clones: Evidence and Implications of Intracolony Heterogeneity in Mesenchymal Stem Cells
Authors: Rennerfeldt Deena A. , Van Vliet Krystyn J.
Published: February 2016

The emergence of heterogeneity in putative mesenchymal stem cell (MSC) populations during in vitro expansion is not appreciated fully by the various communities who study, engineer, and use such stem cells. However, this functional diversity holds direct implications for basic research and therapeutic applications of MSCs that require predictable phenotypic function and efficacy. Despite numerous clinical trials pursuing MSC therapies, the in vitro expansion of homogeneous populations to therapeutically relevant quantities remains an elusive goal. Variation in MSC cultures has been noted not only among donors and within populations expanded from the same donor, but also debatably within single-cell-derived colonies. The potential for even intracolony heterogeneity suggests that any purified subpopulation will inevitably become heterogeneous upon further expansion under current culture conditions. Here, we review the noted or retrospective evidence of intracolony MSC heterogeneity, to facilitate discussion of its possible causes and potential solutions to its mitigation. This analysis suggests that functional diversity within an MSC colony must be considered in design of experiments and trials for even nonclonal stem cell populations, and can be mitigated or even exploited when the mechanisms of onset are better understood.
Differentiation of Vascular Stem Cells Contributes to Ectopic Calcification of Atherosclerotic Plaque
Authors: Leszczynska Aleksandra , O'Doherty Aideen , Farrell Eric , Pindjakova Jana , O'Brien Fergal J. , O'Brien Timothy , Barry Frank , Murphy Mary
Published: February 2016

The cellular and molecular basis of vascular calcification (VC) in atherosclerosis is not fully understood. Here, we investigate role of resident/circulating progenitor cells in VC and contribution of inflammatory plaque environment to this process. Vessel-derived stem/progenitor cells (VSCs) and mesenchymal stem cells (MSCs) isolated from atherosclerotic ApoE−/− mice showed significantly more in vitro osteogenesis and chondrogenesis than cells generated from control C57BL/6 mice. To assess their ability to form bone in vivo, cells were primed chondrogenically or cultured in control medium on collagen glycosaminoglycan scaffolds in vitro prior to subcutaneous implantation in ApoE−/− and C57BL/6 mice using a crossover study design. Atherosclerotic ApoE−/− MSCs and VSCs formed bone when implanted in C57BL/6 mice. In ApoE−/− mice, these cells generated more mature bone than C57BL/6 cells. The atherosclerotic in vivo environment alone promoted bone formation by implanted C57BL/6 cells. Un-primed C57BL/6 VSCs were unable to form bone in either mouse strain. Treatment of ApoE−/− VSC chondrogenic cultures with interleukin (IL)-6 resulted in significantly increased glycosaminoglycan deposition and expression of characteristic chondrogenic genes at 21 days. In conclusion, resident vascular cells from atherosclerotic environment respond to the inflammatory milieu and undergo calcification. IL-6 may have a role in aberrant differentiation of VSCs contributing to vascular calcification in atherosclerosis.
Human Stem Cells Overexpressing miR-21 Promote Angiogenesis in Critical Limb Ischemia by Targeting CHIP to Enhance HIF-1α Activity
Authors: Zhou Yong , Zhu Youming , Zhang Li , Wu Tao , Wu Tingting , Zhang Wenjie , Decker Ann Marie , He Jiacai , Liu Jie , Wu Yiqun , Jiang Xinqun , Zhang Zhiyuan , Liang Chaozhao , Zou Duohong
Published: February 2016

Critical limb ischemia (CLI) is a severe blockage in the arteries of the lower extremities. However, the effective and optimal treatment for CLI remains to be elucidated. Previous therapeutic research is mainly focused on proangiogenic growth factors administrations. Recently, miR-21 has been revealed to play a crucial role in angiogenesis. Thus, we hypothesize that miR-21 over-expression in human umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) can effectively treat CLI. Herein, UCBMSCs were transduced with lentivirus-miR-21-Luciferase (Lenti-miR-21) or lentivirus- LacZ-Luciferase (Lenti-LacZ). The results indicated that miR-21 induced UCBMSCs proliferation, migration, and angiogenesis in vitro. Subsequently, general observation and laser Doppler perfusion imaging were introduced to detect perfusion in muscles of CLI-nude mice on 1, 4, 7, 14, and 28 day postoperation. There was a significant improvement in blood vessels of the ischemic limb in Lenti-miR-21 group at 7 day compared with the saline or Lenti-LacZ groups. At 28 day, histological analysis confirmed that UCBMSCs over-expressing miR-21 increased neovascularization in CLI. Furthermore, carboxyl terminus of Hsc70-interacting protein (CHIP) was found to be the target gene for miR-21-mediated activation of hypoxia-inducible factor 1α (HIF-1α) in UCBMSCs. In summary, our study demonstrated that over-expressing miR-21 in UCBMSCs could improve neovascularization in CLI through enhancing HIF-1α activity by targeting CHIP, which may hold great therapeutic promise in treating CLI.
siRNA and RNAi optimization
Authors: Alagia Adele , Eritja Ramon
Published: February 2016

The discovery and examination of the posttranscriptional gene regulatory mechanism known as RNA interference (RNAi) contributed to the identification of small interfering RNA (siRNA) and the comprehension of its enormous potential for clinical purposes. Theoretically, the ability of specific target gene downregulation makes the RNAi pathway an appealing solution for several diseases. Despite numerous hurdles resulting from the inherent properties of siRNA molecule and proper delivery to the target tissue, more than 50 RNA‐based drugs are currently under clinical testing. In this work, we analyze the recent literature in the optimization of siRNA molecules. In detail, we focused on describing the most recent advances of siRNA field aimed at optimize siRNA pharmacokinetic properties. Special attention has been given in describing the impact of RNA modifications in the potential off‐target effects (OTEs) such as saturation of the RNAi machinery, passenger strand‐mediated silencing, immunostimulation, and miRNA‐like OTEs as well as to recent developments on the delivery issue. The novel delivery systems and modified siRNA provide significant steps toward the development of reliable siRNA molecules for therapeutic use. WIREs RNA 2016, 7:316–329. doi: 10.1002/wrna.1337

This article is categorized under:

RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry

Regulatory RNAs/RNAi/Riboswitches > RNAi: Mechanisms of Action

RNA in Disease and Development > RNA in Disease
Laparoscopic Versus Open Distal Pancreatectomy for Pancreatic Adenocarcinoma
Authors: Stauffer John A. , Coppola Alessandro , Mody Kabir , Asbun Horacio J.
Published: February 2016

Background

Laparoscopic distal pancreatectomy (LDP) has been shown to have short‐term benefits over open distal pancreatectomy (ODP). Its application for pancreatic ductal adenocarcinoma (PDAC) remains controversial.

Methods

From 1995 to 2014, 72 patients underwent distal pancreatectomy for PDAC at a single institution and were included in the study. Postoperative and long‐term outcomes of patients undergoing LDP (n = 44) or ODP (n = 28) were compared.

Results

LDP was associated with less blood loss (332 vs. 874 mL, p = 0.0012) and lower transfusion rates than ODP (18.2 vs. 50 %, p = 0.0495). Operative time was similar (254 vs. 266 min) for LDP and ODP; five patients (11.4 %) required conversion to ODP. Pancreatic fistulas (13.6 vs. 7.1 %) and major complications (13.6 vs. 25 %), were similar between LDP and ODP, respectively. Length of hospital stay (5.1 vs. 9.4 days, p = 0.0001) and time to initiate adjuvant therapy (69.4 vs. 95.6 days, p = 0.0441) was shorter for LDP than ODP. Tumor characteristics were similar but LDP was associated with more resected lymph nodes than ODP (25.9 vs. 12.7, p = 0.0001). One‐, three‐, and five‐year survival rates were similar between LDP (69, 41, and 41 %, respectively) and ODP (78, 44, and 32 %, respectively).

Conclusion

LDP is associated with less blood loss and need for blood transfusion, shorter hospital stay, and faster time to initiate adjuvant therapy than ODP for patients with PDAC. Postoperative outcomes and long‐term survival are similar between the two groups. LDP appears to be safe in the treatment of patients with PDAC.
Perioperative Care of the Transgender Patient
Authors: Smith Francis Duval
Published: February 2016

Transgender patients are individuals whose gender identity is not related to their biological sex. Assuming a new gender identity that does not conform to societal norms often results in discrimination and barriers to health care. The exact number of transgender patients is unknown; however, these patients are increasingly seen in health care. Transgender individuals may experience provider‐generated discrimination in health care facilities, including refusal of service, disrespect, and abuse, which contribute to depression and low self‐esteem. Transgender therapies include mental health counseling for depression and low self‐esteem, hormone therapy, and sex reassignment surgery. Health care professionals require cultural competence, an understanding of the different forms of patient identification, and adaptive approaches to care for transgender patients. VA (Veterans Affairs) hospitals provide a model for the care for transgender patients and staff.
The effect of prenatal and intrapartum care on the stillbirth rate among women in rural Ethiopia
Authors: Ballard Karen , Belete Zelalem , Kinfu Hirut , Tadesse Mebkyou , Amin Mohammed , Atnafu Habtamu
Published: February 2016

Objective

To determine whether community‐based prenatal and intrapartum care in Ethiopia results in a lower stillbirth rate.

Methods

Between May and December 2014, a randomly selected sample of women in northern and eastern Ethiopia who had delivered a neonate in the preceding 12 months completed a face‐to‐face survey about their experiences of maternal services and the fetal outcome for each delivery. The stillbirth rates among women delivering at home and at health facilities were compared.

Results

Overall, 4442 women completed surveys. Stillbirth was reported by 42 (1.7%) of the 2437 women who had received prenatal care and 53 (2.8%) of the 1921 women who did not receive prenatal care (P = 0.01). The stillbirth rate was similar among women who delivered in a health center (27/1417 [1.9%]), in a hospital (6/126 [4.8%]), and at home (62/2725 [2.3%]; P = 0.13). However, women experiencing an intrapartum emergency were twice as likely to deliver in a health facility (odds ratio 2.6, 95% confidence interval 2.2–3.0). Satisfaction with health‐center care was moderately good (median score 77.5/100).

Conclusion

The stillbirth rate was reduced among women receiving prenatal care, although delivering in a health facility did not reduce the risk of stillbirth. Improving the quality of health‐center care could lead to their planned use for childbirth, which might reduce stillbirth rates.
Assessment of complications due to intratympanic injections
Authors: Liu Yu‐Chuan , Chi Fan‐Hsiang , Yang Ting‐Hua , Liu Tien‐Chen
Published: February 2016

Objective

The purpose of the study is to report and to analyze the complications following intratympanic injections (ITI) of steroids. The occurrence rate of complications at different ITI sites, four quadrants of eardrum, was also compared.

Methods

A retrospective clinical review in a medical center. Each patient received ITI twice in a week for 2–3 consecutive weeks as a salvage therapy for sudden sensorineural hearing loss. Post‐injection complications, especially transient dizziness and vertigo, were recorded. Patients with acute or chronic vertigo episodes in 1 month were excluded.

Results

A total of 59 patients with sudden sensorineural hearing loss and a total of 278 times of ITI were performed in 1 year. The post‐injection complications included pain, tongue numbness, transient dizziness, vertigo, tinnitus, and a small persistent perforation. There was no significant difference in the occurrence of these complications between the injections sites on the 4 quadrants of the tympanic membrane. However, there was statistical significance in the post‐injection vertiginous episode after IT injections to posterior‐inferior quadrant (Q3) and posterior‐superior quadrant (Q4) compared to anterior‐superior quadrant (Q1) and anterior‐inferior quadrant (Q2) (P = 0.0113).

Conclusion

IT injection is recommended to be applied to the Q2 since the Q1 and Q4 injections are more likely to induce the adverse effect of tongue numbness, while the Q3 and Q4 areas are more likely to induce post‐injection vertigo.
Dwelling in the Anthropocene: Reimagining University Learning Environments in Response to Social and Ecological Change
Authors: Rousell David
Published: February 2016

Over the last three decades, scientists have uncovered the extent of human impacts on the earth's operating systems with increasing clarity and precision. These findings have prompted scientific claims that we have transitioned out of the Holocene and into the Anthropocene epoch in the earth's geological history (Crutzen & Stoermer, 2000). At the same time, the traditional humanist underpinnings of the university have been eroded by the ongoing digitisation, massification, and decentralisation of higher education. This article argues that higher education has a crucial role to play in responding to the Anthropocene thesis, which at the same time provides a powerful impetus for reimagining the university through posthumanist concepts. In developing this analysis, conceptual distinctions are drawn between visions of hope and disaster, the local and the regional, dwelling and construction, and emplacement and displacement in the context of university learning environments. The learning environment is specifically addressed throughout as a fluid and transitional space for experimenting with concepts and practices that operate outside of humanist constructs and disciplinary boundaries. As the very idea of ‘the university campus’ threatens to become an anachronism, the author concludes with a speculative proposition for the reimagining of the university in the Anthropocene era.
The challenges of diagnosis and treatment of dementia in Down’s syndrome
Authors: Vaughan R. M. , McGee C. , Guerin S. , Tyrrell J. , Dodd P.
Published: February 2016

Objectives

People with Down syndrome (DS) are at high risk for developing dementia and early diagnosis is vital in enhancing quality of life. Our aim was to compare our practice to consensus recommendations on evaluation, diagnosis and pharmacological treatment of individuals with DS who develop dementia. We also aimed to establish the average time taken to make a diagnosis of dementia and to commence pharmacotherapy, and to assess tolerability to acetylcholinesterase inhibitors.

Methods

Retrospective chart review in an exhaustive sample containing all current service users attending our service with DS and a diagnosis of dementia (n=20).

Results

The sample was 75% female and 70% had a moderate intellectual disability. The average age at diagnosis of dementia was 52.42 years old. The average time to diagnosis from first symptom was 1.13 years and the average time to commence pharmacotherapy was 0.23 years. A total of 17 patients commenced on acetylcholinesterase inhibitors, and of these seven discontinued medication due to side-effects or lack of efficacy.

Conclusions

The results on anticholinesterases add to the limited pool of data on treatment of dementia in DS. There was an identified need to improve the rates of medical, vision and hearing assessments, and prospective screening. Deficiencies in screening and diagnosis may be addressed by implementing a standardised dementia assessment pathway to include prospective screening and longitudinal assessment using easily administered scales. We highlight the importance of improving the diagnostic process, as a vital window of opportunity to commence a comprehensive care plan may be lost.
Dynamics of laterally confined marine ice sheets
Authors: Kowal Katarzyna N. , Pegler Samuel S. , Worster M. Grae
Published: February 2016

We present an experimental and theoretical study of the dynamics of laterally confined marine ice sheets in the natural limit in which the long, narrow channel into which they flow is wider than the depth of the ice. A marine ice sheet comprises a grounded ice sheet in contact with bedrock that floats away from the bedrock at a ‘grounding line’ to form a floating ice shelf. We model the grounded ice sheet as a viscous gravity current resisted dominantly by vertical shear stresses owing to the no-slip boundary condition applied at the bedrock. We model the ice shelf as a floating viscous current resisted dominantly by horizontal shear stresses owing to no-slip boundary conditions applied at the sidewalls of the channel. The two shear-dominated regions are coupled by jump conditions relating force and fluid flux across a short transition region downstream of the grounding line. We find that the influence of the stresses within the transition region becomes negligible at long times and we model the transition region as a singular interface across which the ice thickness and mass flux can be discontinuous. The confined shelf buttresses the sheet, causing the grounding line to advance more than it would otherwise. In the case that the sheet flows on a base of uniform slope, we find asymptotically that the grounding line advances indefinitely as $t^{1/3}$, where $t$ is time. This contrasts with the two-dimensional counterpart, for which the shelf provides no buttressing and the grounding line reaches a steady state (Robison, J. Fluid Mech., vol. 648, 2010, pp. 363–380).
A numerical study of shear layer characteristics of low-speed transverse jets
Authors: Iyer Prahladh S. , Mahesh Krishnan
Published: February 2016

Direct numerical simulation (DNS) and dynamic mode decomposition (DMD) are used to study the shear layer characteristics of a jet in a crossflow. Experimental observations by Megerian et al. (J. Fluid Mech., vol. 593, 2007, pp. 93–129) at velocity ratios ($R=\overline{v}_{j}/u_{\infty }$) of 2 and 4 and Reynolds number ($Re=\overline{v}_{j}D/{\it\nu}$) of 2000 on the transition from absolute to convective instability of the upstream shear layer are reproduced. Point velocity spectra at different points along the shear layer show excellent agreement with experiments. The same frequency ($St=0.65$) is dominant along the length of the shear layer for $R=2$, whereas the dominant frequencies change along the shear layer for $R=4$. DMD of the full three-dimensional flow field is able to reproduce the dominant frequencies observed from DNS and shows that the shear layer modes are dominant for both the conditions simulated. The spatial modes obtained from DMD are used to study the nature of the shear layer instability. It is found that a counter-current mixing layer is obtained in the upstream shear layer. The corresponding mixing velocity ratio is obtained, and seen to delineate the two regimes of absolute or convective instability. The effect of the nozzle is evaluated by performing simulations without the nozzle while requiring the jet to have the same inlet velocity profile as that obtained at the nozzle exit in the simulations including the nozzle. The shear layer spectra show good agreement with the simulations including the nozzle. The effect of shear layer thickness is studied at a velocity ratio of 2 based on peak and mean jet velocity. The dominant frequencies and spatial shear layer modes from DNS/DMD are significantly altered by the jet exit velocity profile.
Determinants of serum 25-hydroxyvitamin D concentration in Finnish children: the Physical Activity and Nutrition in Children (PANIC) study
Authors: Soininen Sonja , Eloranta Aino-Maija , Lindi Virpi , Venäläinen Taisa , Zaproudina Nina , Mahonen Anitta , Lakka Timo A.
Published: February 2016

We studied vitamin D intake, serum 25-hydroxyvitamin D (S-25(OH)D) concentration, determinants of S-25(OH)D and risk factors for S-25(OH)D <50 nmol/l in a population sample of Finnish children. We studied 184 girls and 190 boys aged 6–8 years, analysed S-25(OH)D by chemiluminescence immunoassay and assessed diet quality using 4-d food records and other lifestyle factors by questionnaires. We analysed the determinants of S-25(OH)D using linear regression and risk factors for S-25(OH)D <50 nmol/l using logistic regression. Mean dietary intake of vitamin D was 5·9 (sd 2·1) µg/d. Altogether, 40·8 % of children used no vitamin D supplements. Of all children, 82·4 % did not meet the recommended total vitamin D intake of 10 µg/d. Milk fortified with vitamin D was the main dietary source of vitamin D, providing 48·7 % of daily intake. S-25(OH)D was <50 nmol/l in 19·5 % of children. Consumption of milk products was the main determinant of S-25(OH)D in all children (standardised regression coefficient β=0·262; P<0·001), girls (β=0·214; P=0·009) and boys (β=0·257; P=0·003) in multivariable models. Vitamin D intake from supplements (β=0·171; P=0·035) and age (β=−0·198; P=0·015) were associated with S-25(OH)D in girls. Children who drank ≥450 g/d of milk, spent ≥2·2 h/d in physical activity, had ≥13·1 h/d of daylight time or were examined in autumn had reduced risk for S-25(OH)D <50 nmol/l. Insufficient vitamin D intake was common among Finnish children, one-fifth of whom had S-25(OH)D <50 nmol/l. More attention should be paid to the sufficient intake of vitamin D from food and supplements, especially among children who do not use fortified milk products.
Survival outcomes after surgical resection of pulmonary metastases of head and neck tumours
Authors: Hosokawa S , Funai K , Sugiyama K , Takahashi G , Okamura J , Takizawa Y , Yamatodani T , Mineta H
Published: February 2016

Background:

There is limited information available regarding the benefits and outcomes of resection of pulmonary metastases arising from head and neck cancers.

Methods:

A retrospective review was performed of 21 patients who underwent resection of pulmonary metastases of primary head and neck malignancies at Hamamatsu University Hospital. Clinical staging, treatment methods, pathological subtype (particularly squamous cell carcinoma), disease-free interval and overall survival were evaluated.

Results:

The 5- and 10-year overall survival rates of the study participants were 67.0 per cent and 55.0 per cent, respectively, as determined by the Kaplan–Meier method. The prognosis for patients with a disease-free interval of less than 24 months was poor compared to those with a disease-free interval of greater than 24 months (p = 0.0234).

Conclusion:

Patients with short disease-free intervals, and possibly those who are older than 60 years, should be categorised as having severe disease. However, pulmonary metastases from head and neck malignancies are potentially curable by surgical resection.