bluuebunny/crossref_metadata_2025_split huggingface dataset:
The potential of III‐nitride laser diodes for solid‐state lighting
Authors: Wierer Jonathan J. , Tsao Jeffrey Y. , Sizov Dmitry S. 
Published: February 2014

AbstractThe potential of III‐nitride based laser diodes (LDs) for solid‐state lighting (SSL) is discussed. State‐of‐the‐art blue LDs have higher efficiencies at high input power densities when compared to blue light‐emitting diodes (LEDs). This is because the processes that cause the drop in efficiency at high currents for LEDs are not present in the LD operated under stimulated emission. Projections of efficiency improvement show blue LDs have the potential to be nearly as efficient as blue LEDs and provide similar lumen output at much higher input powers. This result provides the possibility that white sources created from blue LD pumped phosphors could someday become a competitive and viable SSL source. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties and carrier dynamics in m ‐plane InGaN quantum wells
Authors: Marcinkevičius Saulius , Kelchner Kathryn M. , Nakamura Shuji , DenBaars Steven P. , Speck James S. 
Published: February 2014

AbstractScanning near‐field and time‐resolved photoluminescence spectroscopy have been applied to characterize single m‐plane InGaN QW structures. The PL spectra were found to be formed by emission from the extended and the localized states. Lateral dimensions of uniform potential regions were placed around a few tens of nm. It was shown that optimization of the template for the QW growth results in a more uniform emission spectrum and a reduced effect of carrier localization. The radiative recombination time at low temperatures was found to be short, about 0.5 ns. At room temperature, nonradiative recombination via efficient recombination centres was prevailing. Complexes of Ga vacancies with O were suggested to play this role. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atomistic simulations of InGaN/GaN random alloy quantum well LEDs
Authors: López M. , Pecchia A. , Auf der Maur M. , Sacconi F. , Penazzi G. , Di Carlo A. 
Published: February 2014

AbstractIn this work, a random distribution of Indium in a quantum well has been considered to study the effect on the energy gap of a GaN/InGaN/GaN LED device. Monte Carlo sampling technique has been used to generate hundreds of atomistic model structures of the device active region. In order to calculate pseudomorphic strain and internal deformations of the alloy, a multiscale method combining continuous media elasticity and atomistic valence force field models has been used. A multiphysic quantum/classical simulation coupling driftdiffusion with empirical tight‐binding in order to compute the electron and hole states of the system has been performed. The reliable sp3d5s* parametrization has been used in the calculations of the eigenstates. We have found an energy gap difference of 50.9 meV for x (In) = 0.1 molar fraction between using virtual crystal approximation and a random distribution of In which increase with increasing Indium concentration. Moreover, electrons wave function seems to be more sensitive than holes due to Indium fluctuations
Optical anisotropy of m ‐plane nitride air‐gap distributed Bragg reflector microcavities
Authors: Tao Renchun , Arita Munetaka , Kako Satoshi , Arakawa Yasuhiko 
Published: February 2014

AbstractWe investigated the optical anisotropy properties of m‐plane air/AlGaN distributed Bragg reflector microcavities fabricated by the thermal decomposition of GaN. Micro‐photoluminescence measurements were performed at room temperature. From the recorded spectrum, two cavity modes with different polarization direction (parallel to a and c) were observed, which are attributed to the birefringence properties of the non‐polar nitride structure.In addition, the mode with E ‖ a has a higher PL intensity than that of the mode with E ‖ c. Based on k · p Hamiltonians, the matrix elements were calculated around the Γ point, revealing the origin of the mode intensity difference. These results would be very helpful for exciton‐cavity coupling research in non‐polar microcavities. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Luminescence of erbium doped aluminum nitride nanoparticles synthesized using inert gas condensation
Authors: Pandya Sneha G. , Kordesch Martin E. 
Published: February 2014

AbstractErbium doped aluminum nitride (AlN:Er) nanoparticles (NPs) were synthesized using the inert gas condensation (IGC) technique. As deposited AlN:Er NPs with 30 nm to 100 nm diameters were observed using transmission electron microscopy and field emission scanning electron microscopy. Photoluminescence from selected NPs showed Er3+ ion emission peaks similar to those seen in Er doped AlN thin films: 540 nm and 560 nm with peak widths of 6 nm and 10 nm respectively.Luminescence from NPs that were heated in air at 1000 °C consisted of several sharp overlapping peaks in the range of 535 nm to 565 nm. As in thin films, the relative intensity of characteristic Er peaks of these AlN:Er NPs was confirmed to be temperature dependent. This makes Er doped NPs useful for nano‐thermometers. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Viability of the use of thin‐film a‐SiC:H photodiodes for protein identification
Authors: Louro P. , Silva V. , Karmali A. , Vieira M. 
Published: February 2014

AbstractIn this paper, we present a multilayer device based on a‐Si:H/a‐SiC:H that operates as photodetector and optical filter. The use of such device in protein detection applications is relevant in Fluorescence Resonance Energy Transfer (FRET) measurements. This method demands the detection of fluorescent signals located at specific wavelengths bands in the visible part of the electromagnetic spectrum. The device operates in the visible range with a selective sensitivity dependent on electrical and optical bias. Several nanosensors were tested with a commercial spectrophotometer to assess the performance of FRET signals using glucose solutions of different concentrations. The proposed device was used to demonstrate the possibility of FRET signals detection, using visible signals of similar wavelength and intensity. The device sensitivity was tuned to enhance the wavelength band of interest using steady state optical bias at 400 nm. Results show the ability of the device to detect signals in this range. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ab‐initio calculations and structural studies of (SiTe)2(Sb2Te3)n (n: 1, 2, 4 and 6) phase‐change superlattice films
Authors: Saito Y. , Tominaga J. , Fons P. , Kolobov A. V. , Nakano T. 
Published: February 2014

Abstract(SiTe)2(Sb2Te3)n phase‐change superlattices were investigated theoretically and experimentally. Ab‐initio first principle simulations predicted that the (SiTe)2(Sb2Te3)n structures are stable and possess a Dirac semimetal‐like band structure. Calculation of the Z2 invariant indicated that the structure was topologically nontrivial. (SiTe)2(Sb2Te3)n superlattice structures derived from first‐principles were successfully fabricated on a Si substrate by RF‐magnetron sputtering. XRD and TEM indicated that the superlattice films were highly oriented with the 00X planes of Sb2Te3 and the superlattice normal to the substrate surface. The (SiTe)2(Sb2Te3)n superlattice is suggested as new material system for interfacial phase‐change memory applications. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
EFFECTS OF FLOW REGULATION AND NON‐NATIVE SPECIES ON FEEDING HABITS OF EURASIAN OTTER Lutra lutra IN MEDITERRANEAN TEMPORARY RIVERS
Authors: Bueno‐Enciso J. , Díaz‐Ruiz F. , Almeida D. , Ferreras P. 
Published: February 2014

ABSTRACTIn Mediterranean temporary rivers, ecological resources greatly fluctuate because of the high hydrological variability throughout the year. However, flow regulation prevents this natural regime and commonly entails associated non‐native species, which change the structure of aquatic communities. Nonetheless, few studies have tested the interaction of these two disruptive factors (flow regulation and non‐native species) and their synergistic effects on the Eurasian otter (Lutra lutra) diet at the river scale. The aim of this study was to compare the seasonal feeding habits of the otter between a temporary non‐regulated stretch and two regulated stretches invaded by non‐native species in a Mediterranean water course. The Bullaque River (Guadiana River Basin, central Spain) was seasonally sampled for otter spraints and prey abundance assessed from December 2009 to November 2010. Three stretches were considered: high (source, non‐regulated), medium (transition, regulated) and low (confluence, regulated). Diet varied from native prey in the high stretch (amphibians, insects and endemic cyprinids) to non‐native species in the low stretch (red‐swamp crayfish Procambarus clarkii and pumpkinseed sunfish Lepomis gibbosus). Seasonally, ingested biomass of native prey increased in spring. Diet was more diverse in the high stretch. Otters neutrally selected native cyprinids in the high stretch throughout the year, whereas crayfish was selected in the other two stretches. Overall results showed that flow regulation and non‐native species have increased prey availability for the otter; however, this paper highlights the importance of maintaining natural regimes in Mediterranean temporary rivers to conserve native communities and thus minimally impact food webs in Iberian freshwaters. Copyright © 2014 John Wiley & Sons, Ltd.
Cell Senescence Abrogates the Therapeutic Potential of Human Mesenchymal Stem Cells in the Lethal Endotoxemia Model
Authors: Carlos Sepúlveda Juan , Tomé María , Eugenia Fernández María , Delgado Mario , Campisi Judith , Bernad Antonio , González Manuel A. 
Published: February 2014

Abstract
Mesenchymal stem cells (MSCs) possess unique paracrine and immunosuppressive properties, which make them useful candidates for cellular therapy. Here, we address how cellular senescence influences the therapeutic potential of human MSCs (hMSCs). Senescence was induced in bone marrow-derived hMSC cultures with gamma irradiation. Control and senescent cells were tested for their immunoregulatory activity in vitro and in vivo, and an extensive molecular characterization of the phenotypic changes induced by senescence was performed. We also compared the gene expression profiles of senescent hMSCs with a collection of hMSCs used in an ongoing clinical study of Graft Versus Host disease (GVHD). Our results show that senescence induces extensive phenotypic changes in hMSCs and abrogates their protective activity in a murine model of LPS-induced lethal endotoxemia. Although senescent hMSCs retain an ability to regulate the inflammatory response on macrophages in vitro, and, in part retain their capacity to significantly inhibit lymphocyte proliferation, they have a severely impaired migratory capacity in response to proinflammatory signals, which is associated with an inhibition of the AP-1 pathway. Additionally, expression analysis identified PLEC, C8orf48, TRPC4, and ZNF14, as differentially regulated genes in senescent hMSCs that were similarly regulated in those hMSCs which failed to produce a therapeutic effect in a GVHD trial. All the observed phenotypic alterations were confirmed in replicative-senescent hMSCs. In conclusion, this study highlights important changes in the immunomodulatory phenotype of senescent hMSCs and provides candidate gene signatures which may be useful to evaluate the therapeutic potential of hMSCs used in future clinical studies. Stem Cells 2014;32:1865–1877
Concise Review: Genetic Dissection of Hypoxia Signaling Pathways in Normal and Leukemic Stem Cells
Authors: Gezer Deniz , Vukovic Milica , Soga Tomoyoshi , Pollard Patrick J. , Kranc Kamil R. 
Published: February 2014

Abstract
Adult hematopoiesis depends on rare multipotent hematopoietic stem cells (HSCs) that self-renew and give rise to progenitor cells, which differentiate to all blood lineages. The strict regulation of the fine balance between self-renewal and differentiation is essential for normal hematopoiesis and suppression of leukemia development. HSCs and progenitor cells are commonly assumed to reside within the hypoxic BM microenvironment, however, there is no direct evidence supporting this notion. Nevertheless, HSCs and progenitors do exhibit a hypoxic profile and strongly express Hif-1α. Although hypoxia signaling pathways are thought to play important roles in adult HSC maintenance and leukemogenesis, the precise function of Hif-dependent signaling in HSCs remains to be uncovered. Here we discuss recent gain-of-function and loss-of-function studies that shed light on the complex roles of hypoxia-signaling pathways in HSCs and their niches in normal and malignant hematopoiesis. Importantly, we comment on the current and often contrasting interpretations of the role of Hif-dependent signaling in stem cell functions. Stem Cells 2014;32:1390–1397
Insulin-Like Growth Factor Promotes Cardiac Lineage Induction In Vitro by Selective Expansion of Early Mesoderm
Authors: Engels Marc C. , Rajarajan Kuppusamy , Feistritzer Rebecca , Sharma Arun , Nielsen Ulrik B. , Schalij Martin J. , Vries Antoine A.F. , Pijnappels Daniël A. , Wu Sean M. 
Published: February 2014

Abstract
A thorough understanding of the developmental signals that direct pluripotent stem cells (PSCs) toward a cardiac fate is essential for translational applications in disease modeling and therapy. We screened a panel of 44 cytokines/signaling molecules for their ability to enhance Nkx2.5+ cardiac progenitor cell (CPC) formation during in vitro embryonic stem cell (ESC) differentiation. Treatment of murine ESCs with insulin or insulin-like growth factors (IGF1/2) during early differentiation increased mesodermal cell proliferation and, consequently, CPC formation. Furthermore, we show that downstream mediators of IGF signaling (e.g., phospho-Akt and mTOR) are required for this effect. These data support a novel role for IGF family ligands to expand the developing mesoderm and promote cardiac differentiation. Insulin or IGF treatment could provide an effective strategy to increase the PSC-based generation of CPCs and cardiomyocytes for applications in regenerative medicine. Stem Cells 2014;32:1493–1502
Concise Review: Evidence for CD34 as a Common Marker for Diverse Progenitors
Authors: Sidney Laura E. , Branch Matthew J. , Dunphy Siobhán E. , Dua Harminder S. , Hopkinson Andrew 
Published: February 2014

AbstractCD34 is a transmembrane phosphoglycoprotein, first identified on hematopoietic stem and progenitor cells. Clinically, it is associated with the selection and enrichment of hematopoietic stem cells for bone marrow transplants. Due to these historical and clinical associations, CD34 expression is almost ubiquitously related to hematopoietic cells, and it is a common misconception that CD34-positive (CD34+) cells in nonhematopoietic samples represent hematopoietic contamination. The prevailing school of thought states that multipotent mesenchymal stromal cells (MSC) do not express CD34. However, strong evidence demonstrates CD34 is expressed not only by MSC but by a multitude of other nonhematopoietic cell types including muscle satellite cells, corneal keratocytes, interstitial cells, epithelial progenitors, and vascular endothelial progenitors. In many cases, the CD34+ cells represent a small proportion of the total cell population and also indicate a distinct subset of cells with enhanced progenitor activity. Herein, we explore common traits between cells that express CD34, including associated markers, morphology and differentiation potential. We endeavor to highlight key similarities between CD34+ cells, with a focus on progenitor activity. A common function of CD34 has yet to be elucidated, but by analyzing and understanding links between CD34+ cells, we hope to be able to offer an insight into the overlapping properties of cells that express CD34. Stem Cells 2014;32:1380–1389
Crude extract of Rheum palmatum L inhibits migration and invasion of LS1034 human colon cancer cells acts through the inhibition of matrix metalloproteinase‐2/‐9 by MAPK signaling
Authors: Ma Yi‐Shih , Hsiao Yu‐Ping , Lin Ju‐Hwa , Hsu Shu‐Chun , Chueh Fu‐Shin , Weng Shu‐Wen , Lai Kuang‐Chi , Lin Jaung‐Geng , Chung Jing‐Gung 
Published: February 2014

ABSTRACTCrude extract of Rheum palmatum L. (CERP) has been used to treat different diseases in the Chinese population for decades. In this study, we investigated the anti‐metastasis effects of CERP on LS1034 human colorectal cancer cells in vitro and examined potential mechanisms of its effects. CERP significantly inhibited cell migration and invasion of LS1034 cells. We also found that CERP inhibited protein levels of matrix metalloproteinases‐2 (MMP‐2) and matrix metalloproteinases‐9 (MMP‐9), and cytosolic NF‐kB p65, RHO A, ROCK 1. Furthermore, we found CERP inhibited protein levels of GRB2, SOS1, MKK7, FAK, Rho A, ROCK 1, VEGF, PKC, AKT, phosphor‐AKT (Thr308), Cyclin D, iNOS, COX2, NF‐kB p65, p‐ERK1/2, p‐JNK1/2, p‐p38, p‐c‐jun, MMP‐2, MMP‐9, MMP‐1, MMP‐7, MMP‐10, UPA and increased the protein level of Ras in LS1034 cells. In conclusion, our results suggest that CERP may be used as a novel anti‐metastasis agent for the treatment of human colon cancer cells. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 852–863, 2015.
Optimization of the Telluride Tl10–x–ySnxBiyTe6 for the Ther­moelectric Energy Conversion
Authors: Kuropatwa Bryan A. , Guo Quansheng , Assoud Abdeljalil , Kleinke Holger 
Published: February 2014

AbstractWe present the thermoelectric properties of the quaternary telluride series Tl10–x–ySnxBiyTe6 including Seebeck coefficient (S), electrical conductivity (σ), and thermal conductivity (κ). Three different Tl concentrations, namely 9, 8.67, and 8.33 Tl per formula unit, were selected followed by variations of the Sn:Bi ratio to tune the properties at each Tl concentration. Additionally, crystal structure data and electronic structure calculations were used to model the data and support the findings. The Tl9(Sn, Bi)Te6 system was found to have the highest power factor (S2σ) displaying a value of 8.1 μW·cm–1·K–2 at 587 K, realized with Tl9Sn0.2Bi0.8Te6. Tl8.67Sn0.50Bi0.83Te6 however, displays values closer to 4 μW·cm–1·K–2 at comparable temperatures. Ultimately, the thermoelectric Figure‐of‐merit was determined to reach a competitive 0.6 at 575 K and 525 K for Tl8.33Sn1.12Bi0.55Te6 and Tl8.67Sn0.50Bi0.83Te6, respectively, thereby outperforming the ternary variants Tl10–xSnxTe6.
Two 1D Coordination Polymers Constructed from Copper(II) Carboxylates and 4,4′‐Dipyridyl Sulfide/4,4′‐Dipyridyl Disulfide
Authors: Tang Long , Gao Loujun , Fu Feng , Cao Jia , Chao Dandan 
Published: February 2014

AbstractBy using pyridyl sulfide ligands, two CuII complexes, [{Cu2[CH3(CH)2COO]4(4‐dps)}2·1.5H2O] (1) and [Cu2[CH3(CH)2COO]4(4‐dpds)] (2) (4‐dps = 4,4′‐dipyridyl sulfide, 4‐dpds = 4,4′‐dipyridyl disulfide), were synthesized and structurally characterized. Complex 1 shows a 1D zigzag chain, further, the adjacent chains are interconnected through O–H···O hydrogen bonds to form 1D nanotubes. Complex 2 consists of alternate linking of a Cu2[CH3(CH)2COO]4 unit and a 4‐dpds ligand to construct same zigzag chains. According to the crystal structures, the full geometry optimizations of complexes 1 and 2 were carried out by using hybrid DFT methods at B3LYP/6‐31G(d) level. Meantime, the DFT‐BS approach was applied to study the magnetic coupling behavior for the two complexes, and the result reveals that the calculated exchange coupling constants J were in good agreement with the experimental θ data. Both 1 and 2 showed antiferromagnetic behavior.
Distributed predictive control of communicating and constrained systems
Authors: Groß D. , Stursberg O. 
Published: February 2014

AbstractThis paper is concerned with distributed model predictive control (DMPC) for distributed linear time invariant systems with decoupled dynamics but coupling via a common cost function and common convex state constraints. In the proposed scheme, local model predictive controllers exchange state measurements and predicted input sequences with bounded uncertainty via possibly delayed communication. A robust model predictive control (RMPC) problem is solved locally under consideration of uncertain information received from other subsystems. The local RMPCs separately optimize over nominal inputs as well as feedback policies for the delayed information and can be implemented as a tractable quadratic program. Under appropriate assumptions, the proposed scheme satisfies the coupling constraints and renders the system practically stable. Simulation results for the control of a platoon of autonomous vehicles relative to a lead vehicle illustrate the effectiveness of the approach.
Scattered Psammomatous Calcifications around Papillary Thyroid Carcinoma
Authors: Lee Yong Sang , Hong Soon Won , Chang Hang‐Seok , Park Cheong Soo 
Published: February 2014

AbstractBackgroundAlthough psammomatous calcification is a characteristic pathologic feature of papillary thyroid carcinoma (PTC), the clinical meaning of histologically determined scattered psammomatous calcifications around PTC is unknown.
ObjectiveThe aim of this study was to evaluate the clinical significance of scattered psammomatous calcifications around PTC.
Materials and methodsBetween January 2009 and July 2009, a total of 546 patients who underwent total thyroidectomy for PTC were enrolled. They were classified into two groups: patients with scattered psammomatous calcifications and patients without psammomatous calcifications. The clinical findings, preoperative diagnostic findings, and histopathologic features were compared between the two groups.
ResultsScattered psammomatous calcifications around PTC were found in 209 patients (38 %), and mostly in younger patients (p = 0.007), those with infiltrative tumor margin (p = 0.022), those with capsule invasion (p = 0.013), and those with lymph node metastasis (p < 0.001). No statistical significance was found in gender, tumor size, multiplicity, and coexisting lymphocytic thyroiditis.ConclusionsAlthough further studies with large‐scale, long‐term follow‐up will be necessary to validate the relationship between scattered psammomatous calcifications and prognosis, scattered psammomatous calcification around PTC may have correlations with the aggressiveness of the PTC.
Networks, Space, and Residents’ Perception of Cohesion
Authors: Boessen Adam , Hipp John R. , Smith Emily J. , Butts Carter T. , Nagle Nicholas N. , Almquist Zack 
Published: February 2014

AbstractCommunity scholars increasingly focus on the linkage between residents’ sense of cohesion with the neighborhood and their own social networks in the neighborhood. A challenge is that whereas some research only focuses on residents’ social ties with fellow neighbors, such an approach misses out on the larger constellation of individuals’ relationships and the spatial distribution of those relationships. Using data from the Twin Communities Network Study, the current project is one of the first studies to examine the actual spatial distribution of respondents’ networks for a variety of relationships and the consequences of these for neighborhood and city cohesion. We also examine how a perceived structural measure of cohesion—triangle degree—impacts their perceptions of neighborhood and city cohesion. Our findings suggest that perceptions of cohesion within the neighborhood and the city depend on the number of neighborhood safety contacts as well as on the types of people with which they discuss important matters. On the other hand, kin and social friendship ties do not impact cohesion. A key finding is that residents who report more spatially dispersed networks for certain types of ties report lower levels of neighborhood and city cohesion. Residents with higher triangle degree within their neighborhood safety networks perceived more neighborhood cohesion.