bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silica Nanosphere Lithography Defined Light Trapping Structures for Ultra-thin Si Photovoltaics
Authors: Vulic Natasa , Choi Jea-Young , Honsberg Christiana B. , Goodnick Stephen M. 
Published: June 2015

ABSTRACTPeriodic arrays of low-aspect ratio silicon nanopillars strongly reduce front surface reflection over a broad wavelength range. In this study, we numerically simulate the reflection of light for thick crystalline silicon substrates nanostructured through a combination of silica nanosphere lithography (SNL) and metal-assisted chemical etching (MaCE), producing ordered arrays of nanopillars with hexagonal periodicity. Using statistical methods, we show that the simulated measurements are in good agreement with the spectrophotometry measurements of the fabricated nanopillars.
Potential of Polarized PVDF/Carbon Nanotube Nanocomposite Scaffolds for Cell Growth
Authors: Lim Jun Young , Park Sook Young , Kim Hyun Jeong , Seo Yongsok 
Published: June 2015

ABSTRACTWe investigated the effects of varying the multiwalled carbon nanotube (MWCNT) contents, as well as the additional use of drawing and poling on the polymorphic behavior and electroactive (piezoelectric) properties of the cast poly(vinylidene fluoride) (PVDF)/MWCNT membranes. Dramatic changes occurred in the polar β-phase crystal contents with the MWCNT loading. An optimum concentration of MWCNT exists for PVDF film polarization. On the other hand, films prepared by electrospinning process exhibited almost constant amount of β-phase with the MWCNT concentration. In this process, polymer fibers with diameters down to the nanometer range, or nanofibers, are formed by subjecting a fluid jet to a high electric field. The remanent polarization and piezoelectric response increased with the β-phase crystals. Cell adhesion and proliferation measured with MTT (Methylthiazolyl diphenyl-tetrazolium bromide) assay coincidentally responded to the polarized PVDF films (β-phase amount).
Surface-Initiated Group-Transfer Polymerization – A Catalytic Approach to Stimuli-Responsive Silicon Nanocrystal Hybrid Materials
Authors: Kehrle Julian , Helbich Tobias , Iqbal Muhammad , Hadidi Lida , Veinot Jonathan G.C. , Rieger Bernhard 
Published: June 2015

ABSTRACTSilicon nanocrystals are photoluminescent materials with a tremendous scope in various niche applications especially the generation of hybrid materials. Our approach for the preparation of stimuli responsive SiNC hybrid materials is based on the application of surface-initiated group-transfer polymerization. As a first step we used photografting of ethyleneglycol di(methacrylate). Then we impregnated remaining methyl acrylic surface groups with the catalyst Cp2YCH2TMS(thf). We performed polymerization studies regarding catalyst and diethyl vinylphosphonate (DEVP) concentrations, highlighting that surface grafting is dependent upon catalyst concentration and independent from added monomer amount. Furthermore, we successfully polymerized methyl methacrylate, dimethyl vinylphosphonate and diisopropyl vinylphosphonate from the SiNC surface.
Characterization of Ge1-x-ySixSny Ternary Alloy Surfaces and Ni/Ge1-x-ySixSny Bilayer Reactions by X-Ray Techniques
Authors: Grzybowski Gordon J. , Kiefer Arnold , Claflin Bruce 
Published: June 2015

ABSTRACTInterest in next generation devices that integrate photonic and electronic functionality is focused on extending the capability of existing group IV material systems while maintaining compatibility with existing processing methods and procedures. One such class of materials which has been recently developed, Ge1-x-ySixSny ternary alloys, is being investigated for integrated Si photonics, solar cell materials, telecommunication applications, and for IR photodetectors. These alloys afford the opportunity to decouple the band gap energies and lattice constants over a wide range of values, potentially yielding direct and indirect character that can be coupled with a variety of different substrates dependent on composition.In the present work, we report X-ray photoelectron spectroscopy (XPS) characterization of Ge1-x-ySixSny alloys grown by gas-source molecular beam epitaxy (GS-MBE) and investigate Ni- Ge1-x-ySiySny bilayer reactions with x-ray diffraction (XRD). The surface oxidation of samples stored in ambient conditions were measured with XPS. High resolution spectra showed chemical shifts of Ge, Si and Sn peaks consistent with Ge-O, Si-O and Sn-O bond formation. Depth profiling indicates a homogeneous composition throughout the bulk of the sample with surface oxidation confined to the top few nanometers. A highly tin-enriched layer was indicated at the surface of the material, while silicon was observed to be either enriched or depleted at the surface depending on the sample.To study the interaction of the ternary with an ohmic contact commonly used in device fabrication processes today, nickel layers 30 nm thick were evaporated onto the alloys and were annealed in nitrogen up to 400 °C for periods as long as 1 hour. The XRD data show that the Ni2(Ge1-x-ySixSny) phase forms first followed by Ni(Ge1-x-ySixSny).
Nano-laminating of SiO2 and TiO2: Atomic layer deposition as a tool to gain new insight into interfaces
Authors: Sobel Nicolas , Hess Christian 
Published: June 2015

ABSTRACTAtomic layer deposition (ALD) was used to deposit a laminate structure of alternating SiO2 and TiO2 monolayers onto a Si wafer. The resulting samples were analyzed in detail by X-ray photoelectron spectroscopy (XPS) revealing a distinct O 1s signature due to the presence of Si-O-Ti species. These findings are in good agreement with those reported for thin ALD films of TiO2 grown on SiO2.
MOF-177/graphene composite as a selective sensor for nitro aromatic compounds
Authors: Neti Venkata 
Published: June 2015

ABSTRACTA zinc-based metal-organic framework, MOF-177, was synthesized on the surface of benzoic acid functionalized reduced graphene oxide (BFG). Large amount of BFG (30wt %) slightly improved the stability of the MOF on the graphene surface, decreased the porosity of the composite, and resulted in 1mm long and 50µm wide microrods of MOF-177/BFG composites which act as a selective sensor for trinitrophenol compared to trinitrotoluene.
Nanofiber-Based Membrane Separators for Lithium-ion Batteries
Authors: Alcoutlabi Mataz , Lee Hun , Zhang Xiangwu 
Published: June 2015

ABSTRACTNanofiber-based membranes were prepared by two different methods for use as separators for Lithium-ion batteries (LIBs). In the first method, Electrospinning was used for the fabrication of Polyvinylidene fluoride PVDF nanofiber coatings on polyolefin microporous membrane separators to improve their electrolyte uptake and electrochemical performance. The nanofiber-coated membrane separators show better electrolyte uptake and ionic conductivity than that for the uncoated membranes. In the second method, Forcespinning® (FS) was used to fabricate fibrous cellulose membranes as separators for LIBs. The cellulose fibrous membranes were made by the Forcespinning® of a cellulose acetate solution precursor followed by a subsequent alkaline hydrolysis treatment. The results show that the fibrous cellulose membrane-based separator exhibits high electrolyte uptake and good electrolyte/electrode wettability and therefore can be a good candidate for high performance and high safety LIB separators.
Relevance of Threading Dislocations for the Thermal Oxidation of GaN (0001)
Authors: Reiner Maria , Koller Christian , Pekoll Kurt , Pietschnig Rudolf , Ostermaier Clemens 
Published: June 2015

ABSTRACTThe influence of threading dislocations (TDs) on the dry thermal oxidation of c-plane gallium nitride (GaN) is investigated for oxidation temperatures above 800°C. The transformation of GaN to gallium oxide (Ga2O3) is preferably found at TDs and grain boundaries, showing enhanced vertical oxidation, compared to defect free surface sites. Therefore, the increase in surface roughness commonly obtained upon oxidation is explained by an inhomogeneous chemical reactivity associated with those crystal defects. Additionally, annealing in an N2 atmosphere showed that also decomposition is favored at such chemically reactive spots. Comparison between decomposition and oxidation suggests that at temperatures above 950°C, the Ga2O3 formation is supported by the decomposition of GaN and subsequent oxidation of the metallic gallium.
COMPARATIVE ANALYSIS OF THREE-DIMENSIONAL NANOSTRUCTURE OF POROUS BIOCOMPATIBLE SCAFFOLDS MADE OF RECOMBINANT SPIDROIN AND SILK FIBROIN FOR REGENERATIVE MEDICINE
Authors: Agapova O. I. , Efimov A. E. , Moisenovich M. M. , Bogush V. G. , Agapov I. I. 
Published: June 2015

Aim.To perform a comparison of three-dimensional nanostructure of porous biocompatible scaffolds made of fibroinBombix moriand recombinant spidroin rS1/9.Materials and methods.Three-dimensional porous scaffolds were produced by salt leaching technique. The comparison of biological characteristics of the scaffolds shows that adhesion and proliferation of mouse fibroblastsin vitroon these two types of scaffolds do not differ significantly. Comparative experimentsin vivoshow that regeneration of bone tissue of rats is faster with implantation of recombinant spidroin scaffolds. Three-dimensional nanostructure of scaffolds and interconnectivity of nanopores were studied with scanning probe nanotomography (SPNT) to explain higher regenerative activity of spidroin-based scaffolds.Results.Significant differences were detected in the integral density and volume of pores: the integral density of nanopores detected on 2D AFM images is 46 μm–2 and calculated volume porosity is 24% in rS1/9-based scaffolds; in fibroin-based three-dimensional structures density of nanopores and calculated volume porosity were 2.4 μm–2 and 0.5%, respectively. Three-dimensional reconstruction system of nanopores and clusters of interconnected nanopores in rS1/9-based scaffolds showed that volume fraction of pores interconnected in percolation clusters is 35.3% of the total pore volume or 8.4% of the total scaffold volume.Conclusion.Scanning probe nanotomography method allows obtaining unique information about topology of micro – and nanopore systems of artificial biostructures. High regenerative activity of rS1/9-based scaffolds can be explained by higher nanoporosity of the scaffolds.
Molecular Phenotype of Breast Cancer According to Time Since Last Pregnancy in a Large Cohort of Young Women
Authors: Collins Laura C. , Gelber Shari , Marotti Jonathan D. , White Sarah , Ruddy Kathryn , Brachtel Elena F. , Schapira Lidia , Come Steven E. , Borges Virginia F. , Schedin Pepper , Warner Ellen , Wensley Taylor , Tamimi Rulla M. , Winer Eric P. , Partridge Ann H. 
Published: May 2015

Abstract

Background.
The increase in breast cancer risk during pregnancy and postpartum is well known; however, the molecular phenotype of breast cancers occurring shortly after pregnancy has not been well studied. Given this, we investigated whether nulliparity and the time interval since pregnancy among parous women affects the breast cancer phenotype in young women.

Materials and Methods.
We examined molecular phenotype in relation to time since pregnancy in a prospective cohort of 707 young women (aged ≤40 years) with breast cancer. Parity was ascertained from study questionnaires. Using tumor histologic grade on central review and biomarker expression, cancers were categorized as luminal A- or B-like, HER2 enriched, and triple negative.

Results.
Overall, 32% were luminal A-like, 41% were luminal B-like, 9% were HER2 enriched, and 18% were triple negative. Although, numerically, patients diagnosed &gt;5 years after pregnancy had more luminal A-like subtypes than women with shorter intervals since pregnancy, there was no evidence of a relationship between these intervals and molecular subtypes once family history of breast cancer and age at diagnosis were considered.

Conclusion.
Distribution of breast cancer molecular phenotype did not differ significantly among young women by parity or time interval since parturition when important predictors of tumor phenotype such as age and family history were considered.

Implications for Practice:
Distribution of breast cancer molecular phenotype did not differ among parous young women by time interval since pregnancy. The implication of these findings for clinical practice suggests that pregnancy-associated breast cancers may be seen up to 5 years beyond parturition.
Orientación de las flores de dos poblaciones norteñas de Pachycereus pecten-aboriginum (Cactaceae)
Authors: Aguilar Gastelum Ileem , Molina-Freaner Francisco 
Published: May 2015

Varios estudios previos han documentado que algunas cactáceas columnares muestran orientación ecuatorial de sus flores. Sin embargo, se desconoce qué tan general es este patrón de orientación entre las cactáceas que producen flores laterales. Pachycereus pecten-aboriginum es una especie que produce flores laterales y que tiene una amplia distribución en México. En este trabajo se describe el patrón de distribución de las flores de dos poblaciones norteñas de P. pecten-aboriginum y se explora su relación con la intercepción de radiación fotosintéticamente activa (RFA). Se eligieron dos poblaciones de P. pecten-aboriginum del estado de Sonora donde se midió el azimut de las costillas y el número de estructuras reproductivas por costilla. Para una de las poblaciones se estimó la RFA interceptada por las costillas de diferente orientación, se colectaron flores orientadas al este, sur y oeste y se contó el número de óvulos por flor. Las flores de ambas poblaciones tuvieron un promedio de orientación de 191.5º ± 69.7º y 194.6º ± 61.8º, mostrando una orientación significativa hacia el sur. El análisis del número de óvulos por flor no mostró diferencias significativas entre costillas de diferente orientación. Los valores diarios de intercepción de RFA mostraron que las costillas orientadas hacia el sur y el ápice son las superficies que más radiación interceptan, mientras que las costillas orientadas hacia el norte son las que menos interceptan. Los resultados se comparan con los datos de otras especies y se discute el posible mecanismo involucrado en la orientación de las flores de esta especie.
The bumble bees (Hymenoptera: Apidae: <i>Bombus</i>) of Arkansas, fifty years later
Authors: Tripodi Amber D. , Szalanski Allen L. 
Published: June 2015

Many species of bumble bees (Hymenoptera: Apidae: Bombus Latreille) are declining throughout their ranges in North America, yet detecting population trends can be difficult when historical survey data are lacking. In the present study, contemporary data is compared to a 1965 survey to detect changes in bumble bee distributions throughout Arkansas. Using county-level records as a point of comparison to look for changes in state-wide occurrence among species over time, we find that state-level changes reflect national trends. Contemporary records of Bombus bimaculatus Cresson and B. impatiens Cresson have more than tripled, while records for B. pensylvanicus (De Geer) show a decline to 61% of historical levels. Although B. fervidus (Fabricius) has been reported infrequently in the state, misidentifications may have led to an overestimation of the state’s species richness. In addition to an updated assessment of the bumble bees of Arkansas, we also provide new, localized information on the seasonal phenology and plant preferences of each species that can be used to guide conservation efforts.
An Application of Subgroup Discovery Algorithm on the Case of Decentralization and Quality of Governance in EU
Authors: Umek Lan 
Published: June 2015

This paper analyses a statistical relationship between the decentralization of the EU countries and the quality of their governance. The degree of decentralization is measured from a fiscal and political point of view, and the quality of governance by multiple indicators and citizen opinions. The paper presents a subgroup discovery algorithm which is capable of analysing two sets of several variables, and uses it for the analysis of EU countries. The paper is one of the first to use the data mining methods from the social sciences domain. The used algorithm has discovered some interesting patterns which show a desired relationship. We have discovered that the proportion of public sector employees is one of the most important indicators, which strongly correlates with the degree of trust in the European and national institutions, the government effectiveness and the perception of corruption.
Collective Agreement for Members of Slovenian Armed Forces: Reflections on Features of Collective Negotiations in the Public Sector for the Military Profession
Authors: Štampar Ljubo 
Published: June 2015

In the Republic of Slovenia, the military is an organization that, like elsewhere in the European Union (EU), belongs to the public sector. The military service is a part of the public service sector and treated with a single collective agreement for the public sector. Despite certain theses (Janowitz 1977, Moskos 1986, Callaghan and Kernic 2003, Garb 2008) about the growing similarity of the military profession with professions in the public sector or other civilian occupations, work in the military is unique because of the specific role of the military in society. However, the military profession has sufficient similarities with other public sector professions in peacetime circumstances, so that soldiers should be granted the right to bargain the economic conditions of their employment. Through the process of collective bargaining, either within the public sector or individually, they could ensure compensation for the restrictions and requirements contained in the work of soldiers. The most important European institutions, in terms of safety and protection of the rights in the European region, are following the trend of changes in the security environment, new tasks of the military organization, the changed nature of the military profession in the postmodern era, and defend the concept of the “citizen in uniform”. Through resolutions, recommendations and memorandums, they are following the trend of increasing demands for the equalization of the rights of soldiers with the rights of other citizens. In particular, the right of unions to organize and the right for the possibilities to negotiate conditions of employment are emphasized. In the EU, there are two approaches regarding the possibility of bargaining on the economic conditions of employment for soldiers. Both provide the possibility of obtaining a special allowance for soldiers serving the country.
Valuing the Seed of an Improved Switchgrass Cultivar
Authors: Gouzaye Amadou , Epplin Francis M. , Wu Yanqi 
Published: June 2015

ABSTRACTSwitchgrass (Panicum virgatum L.) has been identified as a model perennial grass species to compete with alternative sources for providing biomass to fulfill cellulosic biofuels provisions of the US Energy Independence and Security Act of 2007. The objective of this study is to determine the value of a more productive switchgrass variety relative to that of the best available alternative. Biomass data were produced in an experiment with four commercial switchgrass cultivars (Alamo, Blackwell, Kanlow, and Cave‐in‐Rock) and five experimental lines over 4 yr at Stillwater, OK. One of the experimental lines, Cimarron, was released as a cultivar in 2008 during the experiment. The remaining four experimental lines were NL93‐2, NSL 2001‐1, NL 94‐2001‐1, and NSU 95‐2001. An ANOVA model is used to test for differences in switchgrass yield. Enterprise budgets are used to calculate net returns and stochastic efficiency analysis is used to investigate yield risk. For a farm‐gate biomass price of $50 Mg−1, expected net returns were estimated to be $80 ha−1 yr−1 greater in postestablishment years for Cimarron than for Alamo. Assuming a year for establishment, nine postestablishment production years, a farm‐gate biomass price of $50 Mg−1, a discount rate of 6.5%, and environmental conditions similar to those that prevailed during the field experiment, the net present value of seeding a field in the region to Cimarron rather than Alamo would be $501 ha−1.
Industry‐Scale Evaluation of Maize Hybrids Selected for Increased Yield in Drought‐Stress Conditions of the US Corn Belt
Authors: Gaffney Jim , Schussler Jeff , Löffler Carlos , Cai Weiguo , Paszkiewicz Steve , Messina Carlos , Groeteke Jeremy , Keaschall Joe , Cooper Mark 
Published: June 2015

ABSTRACTMaize (Zea mays L.) is among the most important grains contributing to global food security. Eighty years of genetic gain for yield of maize under both favorable and unfavorable stress‐prone drought conditions have been documented for the US Corn Belt, yet maize remains vulnerable to drought conditions, especially at the critical developmental stage of flowering. Optimum AQUAmax (Dupont Pioneer) maize hybrids were developed for increased grain yield under drought and favorable conditions in the US Corn Belt. Following the initial commercial launch in 2011, a large on‐farm data set has been accumulated (10,731 locations) comparing a large sample of the AQUAmax hybrids (78 hybrids) to a large sample of industry‐leading hybrids (4287 hybrids) used by growers throughout the US Corn Belt. Following 3 yr (2011–2013) of on‐farm industry‐scale testing, the AQUAmax hybrids were on average 6.5% higher yielding under water‐limited conditions (2006 locations) and 1.9% higher yielding under favorable growing conditions (8725 locations). In a complementary study, 3 yr (2010–2012) of hybrid‐by‐management‐by‐environment evaluation under water‐limited conditions (14 locations) indicated that the AQUAmax hybrids had greater yield at higher plant populations when compared to non‐AQUAmax hybrids. The combined results from research (2008–2010) and on‐farm (2011–2013) testing throughout the US Corn Belt over the 6‐yr period from 2008 to 2013 indicate that the AQUAmax hybrids offer farmers greater yield stability under water‐limited conditions with no yield penalty when the water limitations are relieved and growing conditions are favorable.
Spatial Variation and Improving Measures of the Utilization Efficiency of Accumulated Temperature
Authors: Liu Yuee , Hou Peng , Xie Ruizhi , Hao Weiping , Li Shaokun , Mei Xurong 
Published: June 2015

ABSTRACTTemperature, especially accumulated temperature, is very important for agricultural productivity. Fully using the heat resource is important for increasing yields of maize (Zea maysL.). To understand spatial variation and improving measures of the utilization efficiency of accumulated temperature, we conducted experiments during the period of 2007 to 2012 at 52 locations in the north spring maize (NM) and Huanghuaihai summer maize (HM) regions of China. We found that the utilization efficiency of ≥10°C accumulated temperature for the whole year (hereafter, UE10y) and residual accumulated temperature for maize were highly correlated with latitude. The UE10y increased by 1.3 and 1.4% for 1° increases in latitude moving northward for NM and HM, respectively. In NM, the variation in residual accumulated temperature was large across the experiment locations, ranging from 76 to 1655°C degree days. To make full use of the heat resource, we studied the effects of delaying harvest, optimum sowing date, and planting‐adapted cultivars on the UE10y and maize yield. We found that, compared to conventional harvest time, delaying harvest significantly increased UE10y and maize yield. For different sowing dates, maize yield increased significantly with increasing UE10y in the northern area of NM but not in the southern area of NM. Regarding the use of different planting‐adapted cultivars, yield potentials of the longest maturity cultivars and cultivars adapted to mechanical grain harvest averaged 17.12 and 14.39 Mg ha–1in NM, which were 27.9 and 7.5% higher than the yield potential of traditional cultivars, respectively.