bluuebunny/crossref_metadata_2025 huggingface dataset:
A Radio Emission Analysis of Classical Nova V351 Pup (1991)
Authors: Wendeln Carolyn , Chomiuk Laura , Finzell Thomas , Linford Justin D. , Strader Jay
Published: May 2017

Previously, Nova Puppis 1991 (V351 Pup) was measured to host one of the most massive ejections claimed in the literature. Multi-frequency radio detections from one epoch were published for this nova in the 1990's; and yet, the remaining data collected by the Karl G. Jansky Very Large Array (VLA) have remained unpublished. In this paper, we analyze the remaining unpublished data sets for V351 Pup at frequencies of 4.9, 8.4, 14.9, and 22.5 GHz. We fit the resulting light curve to a model of expanding thermal ejecta, under the assumption that the radio emission is dominated by free–free radiation and accounting for high levels of clumping in the ejecta. Images of V351 Pup in both the radio (from the VLA) and Hα+[N ii] (from Hubble Space Telescope) exhibit no aspherical structure, strengthening our assumption of spherical symmetry. From expansion parallax methods, we estimate the distance to V351 Pup to be 5.0 ± 1.5 kpc. Our light-curve fit yields a value of

for the ejecta mass, implying that V351 Pup is on the low end of expectations for ejecta mass from classical novae. A comparison between our derived ejecta mass and theoretical models gives evidence for a very massive (1.25

) white dwarf, which is consistent with spectroscopic evidence for an oxygen–neon white dwarf.
Anti-carbamylated Protein Antibodies Are Detectable in Various Connective Tissue Diseases
Authors: Nakabo Shuichiro , Yoshifuji Hajime , Hashimoto Motomu , Imura Yoshitaka , Nakashima Ran , Murakami Kosaku , Kuramoto Nobuo , Ito Shinji , Satoh Junko , Tanaka Masao , Fujii Takao , Mimori Tsuneyo , Ohmura Koichiro
Published: May 2017

Objective.

Anti-carbamylated protein (anti-CarP) antibodies are possible diagnostic biomarkers of anticitrullinated protein antibody (ACPA)-negative rheumatoid arthritis (RA). We aimed to elucidate the prevalence of anti-CarP antibodies in non-RA connective tissue diseases (CTD) because CTD are important in the differential diagnosis of ACPA-negative RA.

Methods.

The sera from 266 patients with RA and 616 patients with CTD and 80 healthy controls were examined using an in-house anti-CarP ELISA.

Results.

The prevalence and the level of anti-CarP antibodies in several CTD were comparable to those in ACPA-negative RA.

Conclusion.

Anti-CarP antibodies are not useful for differentiating ACPA-negative RA from CTD.
Influence of Lactobacillus reuteri L26 Biocenol™ on immune response against porcine circovirus type 2 infection in germ-free mice
Authors: Karaffová V. , Csank T. , Mudroňová D. , Király J. , Revajová V. , Gancarčíková S. , Nemcová R. , Pistl J. , Vilček Š. , Levkut M.
Published: May 2017

Probiotic bacteria are frequently used for prevention of bacterial infections of the gastrointestinal tract, but there are only limited studies on their efficacy against viral gut infections in animals. The aim of this study was to investigate the effect of probioticLactobacillus reuteriL26 BiocenolTMon the innate and adaptive immune responses in germ-free Balb/c mice, experimentally infected by porcine circovirus type 2 (PCV2), which confers immunosuppressive effect. A total of 30 six-week-old female mice were divided into 3 groups and animals in experimental group LPCV (n=10) were inoculated withL. reuteriL26, animals in the control group (C; n=10) and experimental group PCV (n=10) received sterile De Man-Rogosa-Sharpe broth for 7 days. Subsequently, mice from both experimental groups were infected with PCV2; however, mice in the control group received virus cultivation medium (mock). Virus load in faeces, ileum and mesenteric lymph nodes (MLN); as well as gene expression of selected cytokines, immunoglobulin A (IgA) and polymeric Ig receptor (PIgR) in the ileum, and percentage of CD8+, CD19+ and CD49b+CD8- cells in the MLN were evaluated. Our results showed thatL. reuterisignificantly decreased the amount of PCV2 in faeces and in the ileum, and up-regulated the gene expression of chemokines, interferon (IFN)-γ, IgA and PIgR in the ileum. Increased IFN-γ mRNA level was accompanied by higher proportion of natural killer cells and up-regulated IgA and PIgR gene expressions were in accordance with significantly higher percentage of CD19+ lymphocytes in the MLN. These findings indicate that probioticL. reuterihas an antiviral effect on PCV2 in the intestine which is mediated by stimulation of local gut immune response.
Lactobacillus rhamnosus CRL1505 nasal administration improves recovery of T-cell mediated immunity against pneumococcal infection in malnourished mice
Authors: Barbieri N. , Herrera M. , Salva S. , Villena J. , Alvarez S.
Published: May 2017

Immunobiotic lactic acid bacteria have become an interesting alternative for the prevention of respiratory infections. Previously, we demonstrated that the nasal administration of Lactobacillus rhamnosus CRL1505, during repletion of malnourished mice, resulted in diminished susceptibility to the challenge with the respiratory pathogen Streptococcus pneumoniae. Considering the known alterations induced by malnutrition on T lymphocytes and the importance of this cell population on the protection against respiratory pathogens, we aimed to study the effect of L. rhamnosus CRL1505 nasal administration on the recovery of T cell-mediated defences against pneumococcal infection in malnourished mice under nutritional recovery. Malnourished mice received a balanced conventional diet (BCD) for seven days or BCD for seven days with nasal L. rhamnosus CRL1505 supplementation during last two days of the treatment. After the treatments mice were infected with S. pneumoniae. Flow cytometry studies were carried out in bone marrow, thymus, spleen and lung to study T cells, and Th1/Th2 cytokine profiles were determined in broncho-alveolar lavages and serum. The administration of CRL1505 strain to malnourished mice under recovery reduced quantitative and qualitative alterations of CD4+ T cells in the bone marrow, thymus, spleen and lung induced by malnutrition. In addition, CRL1505 treatment augmented Th2-cytokines (interleukin 10 and 4) in respiratory and systemic compartments after pneumococcal infection. These results show that modulation of CD4+ T lymphocytes induced by L. rhamnosus CRL1505 has an important role in the beneficial effect induced by this strain on the recovery of malnourished mice. These data also indicate that nasally administered L. rhamnosus CRL1505 may represent a non-invasive alternative to modulate and improve the T cell-mediated immunity against respiratory pathogens in immunocompromised malnourished hosts.
Effects of Lactobacillus casei CCFM419 on insulin resistance and gut microbiota in type 2 diabetic mice
Authors: Li X. , Wang E. , Yin B. , Fang D. , Chen P. , Wang G. , Zhao J. , Zhang H. , Chen W.
Published: May 2017

The antidiabetic effect of Lactobacillus is increasingly recognized worldwide. In this research, the hypoglycemic activity of Lactobacillus casei CCFM419 was investigated in mice with high-fat and low-dose streptozotocin induced type 2 diabetes. Oral L. casei CCFM419 administration favourably regulated blood glucose balance, increased glucose tolerance and protected islets in the diabetic mice, accompanied by an improvement in lipid metabolism. The homeostasis model of insulin resistance, insulin level and insulin tolerance test and mRNA expression of PI3K/Akt signalling pathway indexes revealed that L. casei CCFM419 had a positive effect on insulin resistance. Furthermore, treatment with L. casei CCFM419 recovered the level of short-chain fatty acids and increased the abundance of butyrate-producing bacteria, such as Allobaculum and Bacteriodes. These results demonstrated that L. casei CCFM419 had the potential ability to ameliorate insulin resistance and hyperglycaemic in type 2 diabetic mice through underlying PI3K/Akt signalling pathway and short-chain fatty acids/gut microbiota pathways.
Intragastric administration of Lactobacillus casei BL23 induces regulatory FoxP3+RORγt+ T cells subset in mice
Authors: Cortes-Perez N.G. , Lozano-Ojalvo D. , Maiga M.A. , Hazebrouck S. , Adel-Patient K.
Published: May 2017

Many studies have highlighted the immunomodulatory properties of the probiotic strain Lactobacillus casei BL23. Recently, we demonstrated the ability of this strain to modulate the Th2-oriented immune response in a mouse model of cow’s milk allergy based on the induction of a Th17-biased immune response. The probiotic function of L. casei has been also linked to gut-microbiota modifications which could been potentially involved in the immune regulation; however, its precise mechanism of action remains poorly understood. In this regard, recent studies suggest that gut microbiota induces a specific subset of CD4+FoxP3+ Treg cells that also express RORγt+, the specific transcription factor of Th17 cells. This new type of regulatory T cells, called type 3 Treg, displays suppressive function during intestinal inflammation, participating in inflammation control. We thus explored the ability of L. casei BL23 to specifically induce type 3 Treg cells, both in vitro and in vivo. Our results showed that intragastric administration of L. casei BL23 to mice induces local and systemic FoxP3+ RORγt+ type 3 Treg cells that could then participate in the beneficial effects of L. casei BL23 in different intestinal-related disorders.
Bioactive compounds inDiospyros mafiensis roots inhibit growth, sporulation and aflatoxin production byAspergillus flavus andAspergillus parasiticus
Authors: Mmongoyo J.A. , Nair M.G. , Linz J.E. , Wu F. , Mugula J.K. , Dissanayake A.A. , Zhang C. , Day D.M. , Wee J.M. , Strasburg G.M.
Published: May 2017

Diospyros mafiensis F. White is a medicinal shrub or small tree (6 m tall) widely distributed in the Zanzibar-Inhambane regional mosaic and traditionally used to treat leprosy, diarrhoea, and skin fungal infections in Tanzania and Mozambique. Our objective was to determine the anti-aflatoxigenic properties of compounds fromD. mafiensis root bark against vegetative growth, sporulation and aflatoxin production byAspergillus flavus andAspergillus parasiticus. Bioassay-guided extraction, fractionation, and isolation of bioactive compounds usingA. parasiticus B62 were employed. The bioactive compounds were elucidated using1H and13CNMR and LC-MS. Growth inhibition was determined by measuring the colony diameter ofA. flavus AF3357 andA. parasiticus SU-1 ATCC56775. Inhibitory effects on sporulation were estimated using a haemocytometer. Total aflatoxin was quantified by direct competitive enzyme-linked immunosorbent assay (ELISA). Bioactive compounds diosquinone (DQ) and 3-hydroxydiosquinone (3HDQ) were identified. DQ weakly inhibitedA. flavus andA. parasiticus vegetative growth (MIC50 > 100 µg/ml) and 3HDQ strongly inhibitedA. flavus (MIC50 = 14.9 µg/ml) andA. parasiticus (MIC50 = 39.1 µg/ml). DQ strongly reduced total aflatoxin production byA. flavus from 157 to 36 ng/plate, and byA. parasiticus from 1,145 ng/plate to 45 ng/plate at 100 µg/ml. 3HDQ reduced total aflatoxin production byA. parasiticus from 1,145 to 32 ng/plate; stimulated production byA. flavus from 157 to 872 ng/plate at 12.5 µg/ml but reduced to 45 ng/plate at 100 µg/ml. In summary, DQ and 3HDQ could be used as natural antifungal compounds to prevent mould growth and aflatoxin accumulation in food and feed.
Monitoring aflatoxin M1 levels in donkey milk produced in Greece, intended for human consumption
Authors: Malissiova E. , Manouras A.
Published: May 2017

Donkey milk is considered as a precious food on nutritional and microbiological grounds. Nevertheless, there is lack of evidence on the issue of chemical contaminants present in donkey milk. Aflatoxin M1 is a contaminant with serious health hazards, that is frequently present in other types of milk. Therefore, this study aimed at assessing the levels of aflatoxin M1 in donkey milk in Greece, intended for human consumption. Thirty-six donkey milk samples were collected over a period of a year from 12 donkey farms, representing 80% of the donkey farms. Samples were analysed with ELISA and analytical results were statistically associated with seasonality and type of feeds used in donkey rearing. Aflatoxin M1 was found in 5 out of 36 samples (13.9%), with a range of 5-26.5 ng/l, while in no sample the toxin was found at a concentration above the EU limit (50 ng/l). There was no statistical difference found among seasons or different types of feed used in donkey farming (P>0.05). Donkey milk in Greece presents very low levels of aflatoxin M1, possibly due to the type of feeds used for donkeys rearing and also due to the very low carryover of aflatoxin B1 to M1 that has been reported for donkeys. Donkey milk is considered as safe with relation to aflatoxin M1, but constant monitoring is advised, as aflatoxin levels in plants for feed are affected by many factors.
Electric vehicle battery reuse: Preparing for a second life
Authors: Canals Casals Lluc , Amante García Beatriz , Cremades Lázaro V.
Published: May 2017

Purpose: On pursue of economic revenue, the second life of electric vehicle batteries is closer to reality. Common electric vehicles reach the end of life when batteries loss between a 20 or 30% of its capacity. However, battery technology is evolving fast and the next generation of electric vehicles will have between 300 and 400 km range. This study will analyze different End of Life scenarios according to battery capacity and their possible second life’s opportunities. Additionally, an analysis of the electric vehicle market will define possible locations for battery repurposing or remanufacturing plants.Design/methodology/approach: Calculating the barycenter of the electric vehicle market offers an optimal location to settle the battery repurposing plant from a logistic and environmental perspective.This paper presents several possible applications and remanufacture processes of EV batteries according to the state of health after their collection, analyzing both the direct reuse of the battery and the module dismantling strategy.Findings: The study presents that Netherlands is the best location for installing a battery repurposing plant because of its closeness to EV manufacturers and the potential European EV markets, observing a strong relation between the EV market share and the income per capita.15% of the batteries may be send back to the an EV as a reposition battery, 60% will be prepared for stationary or high capacity installations such as grid services, residential use, Hybrid trucks or electric boats, and finally, the remaining 25% is to be dismantled into modules or cells for smaller applications, such as bicycles or assisting robots.Originality/value: Most of studies related to the EV battery reuse take for granted that they will all have an 80% of its capacity. This study analyzes and proposes a distribution of battery reception and presents different 2nd life alternatives according to their state of health.
Green supply chain management using the queuing theory to handle congestion and reduce energy consumption and emissions from supply chain transportation fleet
Authors: Aziziankohan Arvin , Jolai Fariborz , Khalilzadeh Mohammad , Soltani Roya , Tavakkoli-Moghaddam Reza
Published: May 2017

Purpose: Nowadays, governments and people pay more attention to use green products due to environmental pollution, irreplaceable energy and shortage of resources. Green products are resulted from the application of green supply chain management strategies to the organizations' performance strategies, so that we can reduce environmental pollutants and wastes and take a step towards saving energy with limited resources.Methodology:  In this paper, the effect of reducing energy consumption in green supply chain is examined by using queuing theory and transportation models. Data was generated and solved by a commercial optimization epackage.Findings:  The findings indicate that suitable assignment of existing transportation fleet with specified capacity, and using queueing theory in a closed-loop network to reduce the queue length and handle congestion, can cause a reduction in energy consumption by optimizing transportation and waiting times in a green supply chain.Originality/value: Adopting investment strategy in improving the environmental performance of the supply chain, will yield in many advantages and benefits. This article investigates the effect of queuing theory on reducing waiting time, optimizing energy consumption in green supply chain, and consequently decreasing pollution.
Special issue: Supply chain and logistics decisions under environmental aspect
Authors: Demirel Neslihan
Published: May 2017

This editor’s note has a twofold objective: (1) to present a brief summary about the environmental issues in supply chain and logistics decisions (2) to present general information about the papers published in the special issue.
Outcome of Reverse Shoulder Arthroplasty for Patients With Parkinson's Disease: A Matched Cohort Study
Authors: Cusick Michael C. , Otto Randall J. , Clark Rachel E. , Frankle Mark A.
Published: May 2017

Parkinson's disease (PD) is a progressive neurologic disorder that affects the musculoskeletal system. Currently, the use of reverse shoulder arthroplasty (RSA) for patients with PD has not been adequately studied. The authors sought to determine if RSA provided similar functional outcomes for patients with PD compared with a matched cohort of patients without PD. Between 2004 and 2011, 10 patients with PD (4 men, 6 women) underwent RSA. Patients with PD were matched to patients without PD at a 1:4 ratio based on age (average, 76 years; range, 63–85 years), sex (16 men, 24 women), preoperative diagnosis, and length of follow-up (average, 43 months; range, 24–128 months). Outcome measures included range of motion, visual analog scale (VAS) score, Simple Shoulder Test (SST) score, American Shoulder and Elbow Society (ASES) score, and complication rates. Patients with PD had improvements in SST scores, ASES total scores, and forward flexion; however, they did not show statistically significant improvements in VAS scores, ASES function scores, or other range of motion parameters. There was a significant difference in postoperative functional outcome scores, SST scores, and internal/external rotation between the 2 groups, but no difference in postoperative pain scores, ASES total scores, forward flexion, or abduction. Complications occurred in 4 of 10 patients with PD and 6 of 40 patients without PD. Compared with the matched cohort, patients with PD achieved similar reduction of pain but inferior clinical function following RSA. Improvement in range of motion was less predictable and complication rates were significantly higher in patients with PD. [
Orthopedics.
2017; 40(4):e675–e680.]
Percutaneous Screw Fixation for Scaphoid Fractures
Authors: Al-Ashhab Mohamed E. , Elbegawi Hossam El-Dein A.
Published: May 2017

Treatment of nondisplaced scaphoid waist fractures has evolved from conventional cast immobilization to percutaneous screw insertion. This study assessed clinical and radiologic outcomes of volar percutaneous screw fixation for 15 type B2 scaphoid fractures (according to the Herbert and Fisher classification). All patients were followed for an average of 33 months (range, 6–50 months). All fractures achieved radiographic union at an average of 57 days (range, 35–70 days), requiring no additional procedures. None of the patients showed radiographic signs of osteoarthritis, osteonecrosis of the scaphoid, or hardware-related complications. For scaphoid waist fractures without collapse, percutaneous screw fixation provided satisfactory results with a high rate of union, early return of function, and minimal complications. [
Orthopedics.
2017; 40(4):e729–e734.]
Os Efeitos Alavancagem e Feedback na Volatilidade do Mercado Acionário Brasileiro
Authors: Carvalho Luciano Ferreira , Vieira Flávio Vilela , Ribeiro Kárem Cristina De Souza , Borges Wemerson Gomes
Published: May 2017

O objetivo deste estudo foi realizar uma comparação das volatilidades entre o segmento tradicional e o Novo mercado da BOVESPA de janeiro de 2008 a dezembro de 2012. Além disso, investigou-se a relação retorno das ações e sua volatilidade por meio das teorias da Alavancagem e Feedback. Como método, estimaram-se modelos ARCH/GARCH e regressões por Mínimos Quadrados Ordinários. As evidências empíricas mostram que a volatilidade das ações que fazem parte do novo mercado, é menos reativa e mais persistente quando comparada ao segmento tradicional. Os resultados empíricos revelam também que a volatilidade de longo prazo e a velocidade de convergência para o nível de longo prazo, foi menor para as ações com melhores práticas de governança. Além disso, pode se argumentar que tanto o efeito Alavancagem quanto o efeito Feedback não são os principais fatores explicativos da relação entre o retorno das ações e sua volatilidade, corroborando a teoria comportamental.
Introdução ao modelo de gestão de uma organização portuguesa do Antigo Regime, com particular referência à sua Contabilidade - o Colégio Real dos Nobres (1766)
Authors: Gonçalves Miguel Ângelo Caçoilo , Ribeiro Susana Da Fonseca , Marques Maria Da Conceição , Lira Miguel
Published: May 2017

O artigo explora introdutoriamente uma antiga instituição de ensino portuguesa: o Colégio Real dos Nobres. Este estabelecimento de ensino, fundado em Lisboa em 1761 e inaugurado em 1766, constituiu uma entidade integrante da reforma da instrução pública empreendida pelo Marquês de Pombal no reinado de D. José. O trabalho amplia os limites tradicionais da definição de organizações sem fins lucrativos para a estender a entidades de ensino do Antigo Regime português. O principal objetivo é o de expor os traços principais da organização, gestão e administração escolar desse remoto estabelecimento de ensino, à luz do discurso moderno aplicado na compreensão dos fenómenos adstritos às áreas da educação e da gestão de entidades do sector não lucrativo. Procura-se também efetuar referências no que respeita à ligação Colégio dos Nobres e Contabilidade. Usou-se a metodologia qualitativa e o método de análise de textos e documentos, em particular fontes primárias. As conclusões mais relevantes prendem-se com o facto de o colégio utilizar um sistema de contabilidade por partidas dobradas simplificado e de a entidade, apesar de ter modelos de governação, tanto executiva como financeira, absolutamente inovadores para a época, falhou em aspetos de índole pedagógica, como sejam a inadequação de programas curriculares à idade dos colegiais e o controlo pouco eficaz do comportamento disruptivo do corpo discente.
Efeito da Adoção Antecipada da IFRS 15 na Qualidade da Informação Contábil
Authors: Dani Andreia Carpes , Dos Santos Cleston Alexandre , Panucci Filho Laurindo , Klann Roberto Carlos
Published: May 2017

Diversas mudanças na legislação que rege as práticas contábeis de empresas do setor de construção impulsionaram o do processo de internacionalização das informações sobre receitas de contratos de clientes na contabilidade. O Brasil tem se destacado pela adoção voluntária antecipada da norma IFRS15. Assim, o estudo tem por objetivo verificar a relação entre a qualidade da informação contábil e a adoção antecipada da IFRS 15 pelas empresas brasileiras de construção civil, listadas na BM&FBovespa. O estudo caracteriza-se como descritivo, realizado por meio de análise documental e abordagem quantitativa. A amostra é composta por 23 empresas do setor de construção. Foram analisados dados trimestrais no período de 2013 a 2015. Para a análise dos dados fez-se uso da regressão linear múltipla com dados em painel, tendo como base para medição da qualidade da informação contábil o modelo de value relevance proposto por Ohlson (1995). Os resultados da pesquisa sugerem que a adoção antecipada da IFRS15 auxilia a reduzir o viés de não comparabilidade e possíveis inconsistências que poderiam existir anteriormente, devido à adoção de diferentes critérios de contabilização das receitas derivadas dos contratos de construção.  Além disso, as organizações que adotam voluntariamente a norma, na tentativa de contabilizar e reconhecer corretamente receitas de contratos de clientes, possuem maior relevância informacional, bem como atendem às expectativas do mercado. Diante disso, pode-se afirmar que a adoção antecipada de informações sobre receitas de contratos de construção apresentam relevância para o mercado de capitais, impactando no preço das ações após a publicação dos relatórios financeiros.
Evaluation of the Innovation Potential of an Industrial Enterprise
Authors: Skonieczny Jan , Vagonova Oleksandra , Vilyanskiy Andriy
Published: May 2017

This article discusses the initial stage of formation of an enterprise activity management aimed at the innovative development. The structure of the sources of financing innovative activity of an enterprise is considered. Philosophy of management of the innovative activity of an industrial enterprise is given; factors affecting the level of the innovative activity of an enterprise are outlined. Management algorithm of the innovative activity of an enterprise is worked out.
Improved Interface Trap Density Close to the Conduction Band Edge of a-Face 4H-SiC MOSFETs Revealed Using the Charge Pumping Technique
Authors: Rescher Gerald , Pobegen Gregor , Aichinger Thomas , Grasser Tibor
Published: May 2017

We study the interface properties of 4H silicon carbide Si-face 0001 and a-face 11220 power MOSFETs using the charge pumping technique. MOSFETs produced on the a-face show a higher electron mobility than Si-face devices, although their charge pumping signal is 5 times higher, indicating a higher interface/border trap density. We show the main contribution to the interface/border trap density on a-face devices originates from deep states in a wide range around midgap, whereas Si-face devices show a higher and exponentially increasing interface/border state density close to the conduction band edge of 4H silicon carbide, resulting in reduced mobility.
Three Dimensional Dislocation Analysis of Threading Mixed Dislocation Using Multi Directional Scanning Transmission Electron Microscopy
Authors: Sato Takahiro , Suzuki Yuya , Ito Hiroyuki , Isshiki Toshiyuki , Nakamura Kuniyasu
Published: May 2017

The recently developed multi directional scanning transmission electron microscopy (MD-STEM) technique has been applied to exactly determine the Burgers vector (b) and dislocation vector (u) of a threading mixed dislocation in a silicon carbide (SiC) as-epitaxial wafer. This technique utilizes repeated focused ion beam (FIB) milling and STEM observation of the same dislocation from three orthogonal directions (cross-section, plan-view, cross-section). Cross section STEM observation in the [1-100] viewing direction showed that the burgers vector have a and c components. Subsequent plan view STEM observation in the [000-1] direction indicated that the b=[u -2uuw] (u≠0 and w≠0). Final cross section STEM observation in the [11-20] direction confirmed that the dislocation was an extended dislocation, with the Burgers vector experimentally found to be b = [1-210]a/3 + [0001]c which decomposes into two partial dislocations of bp1 = [0-110]a/3 + [0001]c/2 and bp2 = [1-100]a/3 + [0001]c/2. The dislocation vector u is [-12-10]a/3 + [0001]c. This technique is an effective method to analyze the dislocation characteristics of power electronics devices.
Observation of Basal Plane Dislocation in 4H-SiC Wafer by Mirror Projection Electron Microscopy and Low-Energy SEM
Authors: Isshiki Toshiyuki , Hasegawa Masaki , Orai Yoshihisa , Miyaki Atsushi , Sato Takahiro
Published: May 2017

Basal plane dislocation (BPD) with dislocation lines in shallow areas near the surface in 4H-SiC epitaxial wafer was observed by mirror projection electron microscopy (MPJ) and low-energy scanning electron microscopy (LE-SEM). A contrast of dislocation line of BPD appeared in a MPJ observation as gradually weakened dark line toward the upper stream of offcut of wafer, and the contrast almost agreed with the LE-SEM image taken at the same BPD by not a morphology-sensitive imaging method but a potential-sensitive imaging method. Thus an origin of the contrast corresponding to BPD in MPJ is considered to surface potential change due to charging on dislocation line. MPJ observation can gives a BPD image with same quality as a potential-sensitive image by LE-SEM, in extremely short time and damage-and contamination-free condition at no electron irradiation on wafer.
Exploration of Bulk and Epitaxy Defects in 4H-SiC Using Large Scale Optical Characterization
Authors: Leonard R.T. , Paisley M.J. , Bubel S. , Sumakeris J.J. , Powell A.R. , Khlebnikov Y. , Seaman J.C. , Ambati J. , Burk Albert A. , O’Loughlin Michael J. , Balkas E.
Published: May 2017

In this work, aggregate epitaxial carrot distributions are observed at the crystal, wafer and dislocation defect levels, instead of individual extended carrot defect level. From combining large volumes of data, carrots are observed when both threading screw dislocations (TSD) and basal plane dislocations (BPD) densities are locally high as seen in full wafer maps. Dislocation density distributions in areas of carrot formation are shown, and suggest TSD limit the formation of carrots in regions containing BPD. These data also add support for mechanisms requiring the need for both dissociated BPD and TSD for carrot formation.
Density Functional Theory on NV Center in 4H SiC
Authors: Csóré András , Gali Ádám
Published: May 2017

Paramagnetic defects in solids have become attractive systems for quantum computing as well as magnetometry in recent years. One of the leading contenders is the negatively charged nitrogen-vacancy defect (NV center) in diamond proposed to be highly promising with respect the afore-mentioned applications. In our study we investigate the NCVSi defect in 3C, 4H and 6H SiC as alternative choices with superior properties. Electronic structure of NV center in SiC exhibits S = 1 triplet ground state with the possibility of optical spin polarization. On the other hand, our results obtained by density functional theory calculations may contribute to unambiguously identify the possible defect configurations.
Employing Scanning Spreading Resistance Microscopy (SSRM) for Improving TCAD Simulation Accuracy of Silicon Carbide
Authors: Elpelt Rudolf , Zippelius Bernd , Doering Stefan , Winkler Uwe
Published: May 2017

Computer-Aided-Design for the prediction of the technology process and the physical device properties (TCAD) is a key tool for the development and improvement of new device concepts as well as for the analysis and understanding of device properties and device behavior under application conditions. Apart from physical device models and parameters the precise process simulation of implanted doping profiles is mandatory for a sufficient prediction quality of the subsequent device simulations. In order to verify and improve the accuracy of process simulation, we employ the – for silicon carbide – relatively new method of Scanning Spreading Resistance Microscopy (SSRM) for the characterization of doping profiles.
Growth and Temperature-Depending Raman Characterization of Different Nitrogen-Doped 4H-SiC Crystals
Authors: Yang Xiang Long , Chen Xiu Fang , Peng Yan , Xie Xue Jian , Hu Xiao Bo , Xu Xian Gang , Yu Peng , Wang Rui Qi
Published: May 2017

Different nitrogen-doped 4H-SiC single crystals were grown by the physical vapor transport method through mixing nitrogen gas to the argon growth atmosphere in the composition range from 0% to 10%. The electrical properties of the crystals, including resistivity and mobility were measured by Hall effect and contactless eddy current measurements. The Raman spectra of different N-doped 4H-SiC single crystals were investigated from 173 to 473 K. The temperature and doping dependence of optical modes was analyzed with anharmonic effect. The phonon lifetime was derived from the linewidths of Raman spectra via the energy-time uncertainty relation.
Study of Etching Processes for SiC Defect Analysis
Authors: Wu Ping , Xu Xue Ping , Zwieback Ilya , Hostetler John
Published: May 2017

We investigated selective etching of SiC in molten KOH + NaOH + Na2O2 mixtures in application to defect analysis. Etch rate was measured as a function of etchant composition, temperature and other process variables. Optimal etching conditions were established for reliable differentiation between TSDs, TEDs, BPDs and stacking faults (SF).
Ni-Al-Ti Ohmic Contacts on Al Implanted 4H-SiC
Authors: Fedeli Paolo , Puzzanghera Maurizio , Moscatelli Francesco , Minamisawa Renato Amaral , Alfieri Giovanni , Grossner Ulrike , Nipoti Roberta
Published: May 2017

This study shows that an Al-Ti bilayer with an Al to Ti atomic ratio suitable forohmic contacts on p-type 4H-SiC can be covered by a Ni film during the high temperature alloying process, without altering the ohmic nature, while eliminating a detrimental contact morphology caused by the presence of molten Al-Si during alloying. On 1×1020 cm-3 Al-implanted 4H-SiC layer, the RT specific contact resistance of this Ni-Al-Ti contact measured by TLM-C method is (3 ± 1)×10-6 Ωcm2.
Laser Assisted SiC Wafering Using COLD SPLIT
Authors: Swoboda Marko , Beyer Christian , Rieske Ralf , Drescher Wolfram , Richter Jan
Published: May 2017

Kerf-free wafering techniques hold the potential to drastically reduce material losses in semiconductor manufacturing processes. Spalling processes use externally applied stresses to separate crystalline materials along crystal planes with well-defined thickness. Spalled substrates, however, exhibit striations from crack propagation along the crystal, a pattern called Wallner lines. Here, we demonstrate a wafering process that scales favorably for SiC substrates starting from 1 inch in diameter. To eliminate the Wallner line pattern, we use a laser-conditioning process with high numerical aperture at photon energies below the material bandgap energy, using multi-photon effects. The process leads to SiC surfaces with a roughness after spalling of Ra< 4μm.
Salicide-Like Process for the Formation of Gate and Source Contacts in 4H-SiC TSI-VJFETs
Authors: Stavrinidis Antonis , Konstantinidis George , Vamvoukakis Konstantinos , Zekentes Konstantinos
Published: May 2017

The self-aligned approach allowed to fabricate 4H-SiC VJFETs with conventional contact lithography with only 4 lithography steps. The main problem of this approach was the gate-source leakage current. In order to address this issue, a salicide process has been adopted resulting in a substantial reduction of the gate-source leakage current. The success of this approach paved the way for fabricating high power 4H-SiC devices with extremely low fabrication cost.
10+ kV Implantation-Free 4H-SiC PiN Diodes
Authors: Salemi Arash , Elahipanah Hossein , Zetterling Carl Mikael , Östling Mikael
Published: May 2017

Implantation-free mesa etched 10+ kV 4H-SiC PiN diodes are fabricated, measured and analyzed by device simulation. An area-optimized junction termination extension (O-JTE) is implemented in order to achieve a high breakdown voltage. The diodes design allows a high breakdown voltage of about 19.3 kV according to simulations by Sentaurus TCAD. No breakdown voltage is recorded up to 10 kV with a very low leakage current of 0.1 μA. The current spreading within the thick drift layer is considered and a voltage drop (VF) of 8.3 V and 11.4 V are measured at 50 A/cm2 and 100 A/cm2, respectively. The differential on-resistance (Diff. Ron) of 67.7 mΩ.cm2 and 55.7 mΩ.cm2 are measured at 50 A/cm2 and 100 A/cm2, respectively.
Lifetime Control in SiC PiN Diodes Using Radiation Defects
Authors: Hazdra Pavel , Popelka Stanislav
Published: May 2017

Application of radiation defects for lifetime control in contemporary SiC PiN diodes was investigated using the calibrated device simulator ATLAS from Silvaco, Inc. Recombination models accounting for the effect of deep levels introduced by the irradiation were set according to experimental results obtained by C-V and DLTS measurements performed on low-doped n-type SiC epilayers irradiated with 4.5 MeV electrons and 670 keV protons. Global (4.5 MeV electron irradiation) and local (700 keV proton irradiation) lifetime reduction was then applied on the 2A/10kV SiC PiN diode and the ON-state and reverse recovery characteristics were simulated and compared. Results show that the proton irradiation can substantially improve the trade‑off between the diode ON‑state and turn‑OFF losses. Compared to the electron irradiation, the local lifetime killing by protons allows achieving better trade-off and softer recovery curves.
Demonstration of SiC-MOSFET Embedding Schottky Barrier Diode for Inactivation of Parasitic Body Diode
Authors: Hino Shiro , Hatta Hideyuki , Sadamatsu Koji , Nagahisa Yuichi , Yamamoto Shigehisa , Iwamatsu Toshiaki , Yamamoto Yasuki , Imaizumi Masayuki , Nakata Shuhei , Yamakawa Satoshi
Published: May 2017

External Schottky barrier diodes (SBD) are generally used to suppress the conduction of the body diode of MOSFET. A large external SBD is required for a high voltage module because of its high specific resistance, while the forward voltage of SBD should be kept smaller than the built-in potential of the body diode. Embedding SBD into MOSFET with short cycle length increases maximum source-drain voltage where body diode remains inactive, resulting in high current density of SBD current. We propose a MOSFET structure where an SBD is embedded into each unit cell and an additional doping is applied, which allows high current density in reverse operation without any activation of body diode. The proposed MOSFET was successfully fabricated and much higher reverse current density was demonstrated compared to the external SBD. We can expect to reduce total chip size of high voltage modules using the proposed MOSFET embedding SBD.
Understanding High Temperature Static and Dynamic Characteristics of 1.2 kV SiC Power MOSFETs
Authors: Liu Si Yang , Jiang Yi Fan , Sung Woong Je , Song Xiao Qing , Baliga B. Jayant , Sun Wei Feng , Huang Alex Q.
Published: May 2017

High temperature capability of silicon carbide (SiC) power MOSFETs is becoming more important as power electronics faces wider applications in harsh environments. In this paper, comprehensive static and dynamic parameters of 1.2 kV SiC MOSFETs have been measured up to 250°C. The electrical behaviors with the temperature have been analyzed using the basic device physics and analytical models.
Electrical Stability Impact of Gate Oxide in Channel Implanted SiC NMOS and PMOS Transistors
Authors: Idris Muhammad I. , Weng Ming Hung , Chan H.K. , Murphy A.E. , Smith Dave A. , Young R.A.R. , Ramsay Ewan P. , Clark David T. , Wright Nick G. , Horsfall Alton B.
Published: May 2017

Operation of SiC MOSFETs beyond 300°C opens up opportunities for a wide range of CMOS based digital and analogue applications. However the majority of the literature focuses only on the optimization of a single type of MOS device (either PMOS or more commonly NMOS) and there is a lack of a comprehensive study describing the challenge of optimizing CMOS devices. This study reports on the impact of gate oxide performance in channel implanted SiC on the electrical stability for both NMOS and PMOS capacitors and transistors. Parameters including interface state density (Dit), flatband voltage (VFB), threshold voltage (VTH) and effective charge (NEFF) have been acquired from C-V characteristics to assess the effectiveness of the fabrication process in realising high quality gate dielectrics. The performance of SiC based CMOS transistors were analyzed by correlating the characteristics of the MOS interface properties, the MOSFET 1/f noise performance and transistor on-state stability at 300°C. The observed instability of PMOS devices is more significant than in equivalent NMOS devices. The results from MOS capacitors comprising interface state density (Dit), flatband voltage (VFB), threshold voltage (VTH) for both N and P MOS are in agreement with the expected characteristics of the respective transistors.
Novel Advanced Analytical Design Tool for 4H-SiC VDMOSFET Devices
Authors: di Benedetto Luigi , Licciardo Gian Domenico , Erlbacher Tobias , Bauer Anton J. , Rubino Alfredo
Published: May 2017

An analytical tool to design 4H-SiC power vertical Double-diffused Metal-Oxide-Semiconductor Field-Effect-Transistor is proposed. The model optimizes, in terms of the doping concentration in the Drift–region, the trade–off between the ON–resistance, RON, and the maximum blocking voltage, VBL, that is the Drain-Source voltage for which the avalanche breakdown appears at the p+–well/n-DRIFT junction together with the breakdown of the Gate oxide. Finding such trade-off means to maximize, Figure-Of-Merit. Our results are based on a novel full–analytical model of the electric field in the Gate oxide, EOX, whose generality is ensured by the absence of fitting and empirical parameters. Model results are successfully compared with 2D–simulations covering a wide range of device performances.
Cryogenic Characterisation and Modelling of Commercial SiC MOSFETs
Authors: Woodend Lee J. , Gammon Peter Michael , Shah Vishal A. , Pérez-Tomás Amador , Li Fan , Hamilton Dean P. , Myronov Maksym , Mawby Philip  Andrew
Published: May 2017

Two commercial 1.2 kV SiC MOSFETs have been extensively characterised from 30 to 320 K. The temperature dependence of their I/V characteristics, threshold voltage, and breakdown voltage has been examined and are presented in this paper. Overall, the measured characteristics of both devices demonstrate very similar temperature dependencies and it is shown that below ~100 K any further decrease in temperature has little effect on any of the tested characteristics. Increasing temperature beyond 100 K results in a decrease in drain current for a given drain-source and gate-source voltage, a decrease in threshold voltage, and an increase in breakdown voltage. Successful attempts have been made to model the results of these tests by applying theories found in the literature.
Performance Evaluation and Expected Challenges of Silicon Carbide Power MOSFETs for High Voltage Applications
Authors: Rahimo Munaf
Published: May 2017

This paper presents an overview of the main technical requirements of high voltage Silicon Carbide MOSFETs rated above 3300V when compared to the well-established requirements of Silicon IGBTs and diodes. Combined with a performance evaluation of existing 3300 V SiC MOSFET prototypes from ROHM, the paper will discuss the benefits and challenges facing these devices for targeting mainstream and future topologies employed in high power applications such as those in grid systems, railway traction and industrial drives. The paper will also attempt to provide an outlook into potential development trends towards exploiting the full benefits of SiC MOSFETs.
Thermal and Lattice Misfit Stress Relaxation in Growing AlN Crystal with Simultaneous Evaporation of SiC Substrate
Authors: Argunova Tatiana S. , Gutkin Mikhail Yu. , Shcherbachev Kirill D. , Nagalyuk Sergey , Kazarova Olga P. , Mokhov Evgeniy , Je Jung H.
Published: May 2017

AlN single crystals were prevented from cracking by simultaneous growth and evaporation of SiC substrates. The freestanding crystals (<1 mm thick) were proved continuous by synchrotron phase contrast imaging and used as a model system to investigate the type of dislocation structure near AlN/SiC interface by x-ray diffraction techniques. We have found that, unlike the situation in GaN films, where predominantly edge-type threading dislocations cross the layer along its normal, the dislocations configure to form mosaic structure. We suggest a theoretical model that describes the misfit stress relaxation in growing AlN crystal.
Nanostructuring of Graphene on Semi-Insulating SiC
Authors: Hähnlein Bernd , Breiter Manuela , Stauden Thomas , Pezoldt Jörg
Published: May 2017

Epitaxial graphene nanoribbons were fabricated and geometrically measured via scanning electron microscope in the width range of 3...45nm in a new approach. The critical dimension measurement was improved using Monte Carlo simulations for analyzing back scattering effects of the semi-insulating substrate and gaussian convolutions. Different bias powers during oxygen plasma etching allowed the identification of under-etching depths.
Investigation of Carrot Reduction Effect on 4H-Silicon Carbide Epitaxial Wafers with Optimized Buffer Layer
Authors: Mabuchi Yuichiro , Masuda Tatsuya , Muto Daisuke , Momose Kenji , Osawa Hiroshi
Published: May 2017

We investigated the carrot-defect reduction effect by optimizing the buffer layers of 4H-Silion Carbide (SiC) epitaxial wafers. The SiC epitaxial wafer with the 0.5 μm-thick optimized condition-B buffer layer show the carrot-defect density of 0.13 cm-2, since that with the conventional-A buffer layer were 0.68 cm-2. Although the average bunching length with the optimized condition-B buffer layer was 7-times longer than those with the conventional condition-A buffer layer, we could reduce the bunching length by applying the optimized condition-B only to the initial 0.05 μm-thick buffer layer. Finally, with the initial 0.05 μm-thick optimized condition-B buffer layers, we could achieve the SiC epitaxial wafers with only half the carrot-defect densities of those with the conventional condition-A buffer layers, while the average bunching lengths were less than 100 μm. With this condition, we could achieve the estimated yield of 90.1% with 4 x 4 mm chips, while that with the conventional condition-A buffer layer was 81.9%.
Gains from trade due to within-firm productivity: does services exporting matter?
Authors: Dincer N. Nergiz , Tekin-Koru Ayca
Published: May 2017

This paper focuses on gains from trade due to rising within-firm productivity in presence of services exporting. The complementarity between exporting and investing in productivity enhancements is investigated by using descriptive regressions using rich, firm-level data for the period 2003–2011 for Turkey. The authors use three productivity measures for robustness purposes. The results show that firms that export both goods and services throughout the sample have higher productivity compared to all other firms in the sample. Another important result of the paper is related to the firms that switch from being goods exporters to goods and services exporters, which exhibit higher productivity than firms that export only goods or firms that switch from services exporting to exporting both goods and services. Finally, within-firm gains from trade as measured by the productivity growth of firms is insensitive to the services exporting status. More importantly, the authors observe no effect of any of export status of firms considered in this paper on their productivity growth.