bluuebunny/crossref_metadata_2025 huggingface dataset:
Увеличение порогового напряжения отпирания силовых GaN-транзисторов при использовании низкотемпературной обработки в потоке атомарного водорода
Authors: Ерофеев Е.В. , Федин И.В. , Кутков И.В. , Юрьев Ю.Н.
Published: February 2017

Транзисторы с высокой подвижностью электронов на основе эпитаксиальных гетероструктур AlGaN/GaN являются перспективной элементной базой для создания устройств силовой электроники следующего поколения. Это обусловлено как высокой подвижностью носителей заряда в канале транзистора, так и высокой электрической прочностью материала, позволяющей достичь высоких напряжений пробоя. Для применения в силовых коммутационных устройствах требуются нормально-закрытые GaN-транзисторы, работающие в режиме обогащения. Для создания нормально-закрытых GaN-транзисторов чаще всего используют подзатворную область на основе GaN p-типа проводимости, легированного магнием (p-GaN). Однако оптимизация толщины эпитаксиального слоя p-GaN и уровня легирования позволяет добиться порогового напряжения отпирания GaN-транзисторов, близкого к Vth=+2 В. В настоящей работе показано, что применение низкотемпературной обработки в потоке атомарного водорода подзатворной области на основе p-GaN перед осаждением слоев затворной металлизации позволяет увеличить пороговое напряжение транзистора до Vth=+3.5 В. Наблюдаемые эффекты могут быть обусловлены формированием дипольного слоя на поверхности p-GaN, индуцированного воздействием атомарного водорода. Термическая обработка GaN-транзисторов, подвергшихся водородной обработке, в среде азота при температуре T=250oC в течение 12 ч не выявила деградации электрических параметров транзистора, что может быть обусловено формированием термически стабильного дипольного слоя на границе раздела металл/p-GaN в результате гидрогенезации. DOI: 10.21883/FTP.2017.02.44114.8298
Ориентационный магнитный фазовый переход, индуцированный при ударном нагружении сплава Fe-Cr-Co
Authors: Судьенков Ю.В. , Сарнацкий В.М. , Смирнов И.В.
Published: February 2017

В процессе исследований прочностных характеристик при высокоскоростном деформировании сплавов Fe-Cr-Co обнаружено, что в результате ударного нагружения в образцах и их фрагментах возникает значительная остаточная намагниченность, обусловленная ориентационным магнитным фазовым переходом. В работе определены пороговые давления магнитного фазового перехода и исследовано распределение остаточной намагниченности в образцах. Работа осуществлена в рамках проекта РНФ N 15-19-00182. DOI: 10.21883/FTT.2017.02.44048.113
Атомная подвижность в тройном жидком сплаве Ga--In--Sn эвтектического состава
Authors: Нефедов Д.Ю. , Антоненко А.О. , Подорожкин Д.Ю. , Усков А.В. , Чарная Е.В. , Lee M.K. , Chang J.L. , Haase J. , Michel D. , Кумзеров Ю.А. , Фокин А.В. , Самойлович М.И. , Бугаев А.С.
Published: February 2017

Проведены исследования ядерной спин-решеточной релаксации и сдвига Найта ядер 71Ga, 69Ga и 115In в жидком тройном сплаве галлия, индия и олова эвтектического состава, введенном в поры опаловой матрицы и пористых стекол с размером пор 18 и 7 nm, в сравнении с объемным расплавом. Обнаружено ускорение продольной релаксации и уменьшение сдвига Найта, зависящие от размера пор. Рассчитано время корреляции атомного движения для наноструктурированного расплава в пористых матрицах. Показано, что атомная подвижность в расплаве понижается с уменьшением размера пор. DOI: 10.21883/FTT.2017.02.44062.254
Определение формы инденторов нанотвердомеров интерферометрическим способом
Authors: Казиева Т.В. , Кузнецов А.П. , Губский К.Л. , Понарина М.В. , Решетов В.Н.
Published: February 2017

Предложен способ определения функций площади поверхности алмазных инденторов нанотвердомеров с помощью метрологического атомно-силового микроскопа с трехкоординатным лазерным интерферометром. Были проведены измерения формы граней ряда инденторов типа пирамиды Берковича. Точность измерения координат точек поверхности индентора составила 1 nm. Показано, что в процессе использования инденторов происходит изменение формы их вершины, в частности на первых 100 nm отклонение от идеальной пирамидальной формы может превышать 30 nm. Таким образом, одним из способов верификации функции площади поверхности индентора может быть периодическая поверка инденторов на метрологическом атомно-силовом микроскопе. DOI: 10.21883/PJTF.2017.03.44223.16487
Особенности токопрохождения в гетеропереходных солнечных элементах на основе alpha-Si : H/Si
Authors: Саченко А.В. , Костылев В.П. , Соколовский И.О. , Бобыль А.В. , Вербицкий В.Н. , Теруков Е.И. , Шварц М.З.
Published: February 2017

Рассмотрена специфика формирования темновых ВАХ I(V) гетеропереходных солнечных элементов на основе alpha-Si : H/Si с учетом соотношения между уровнем легирования кремния Nd и величиной избыточной концентрации электронно-дырочных пар Delta n. Показано, что при Delta n≥ Nd ВАХ принципиально отличается от ВАХ классического диода Шокли из-за влияния тыльной поверхности (вследствие дополнительного падения приложенного напряжения). Результаты анализа применены для описания экспериментальных ВАХ, наблюдаемых в работах по исследованию гетеропереходных солнечных элементов на основе alpha-Si : H/Si. Из сравнения экспериментальных и расчетных зависимостей I(V) получены численные значения факторов идеальности их темновых ВАХ. DOI: 10.21883/PJTF.2017.03.44224.16473
Атомно-силовая микроскопия устройства поверхностных слоев интактных фибробластов
Authors: Халисов М.М. , Анкудинов А.В. , Пеннияйнен В.А. , Няпшаев И.А. , Кипенко А.В. , Тимощук К.И. , Подзорова С.А. , Крылов Б.В.
Published: February 2017

Интактные фибробласты, находящиеся на обработанной коллагеном подложке, исследованы с помощью атомно-силового микроскопа с использованием двух типов зондов: стандартных, с радиусом закругления кончика 2-10 nm, и специальных, с закрепленным на кончике SiO2 шариком калиброванного радиуса 325 nm. Установлено, что независимо от выбранного типа зонда средняя максимальная высота фибробласта оказывается на уровне ~ 1.7 mum, а средняя жесткость контакта зонда с клеткой составляет ~ 16.5 mN/m. Результат проявляет особенность устройства фибробласта, заключающуюся в том, что по отношению к внутреннему содержимому клетки ее внешние слои ведут себя как жесткая оболочка, которая продавливается зондом на глубину, зависящую только от величины нагрузки. DOI: 10.21883/PJTF.2017.04.44298.16461
Directors, auditors and secretaries roles and corporate governance system: Identity theory perspective
Authors: Osemeke Louis
Published: February 2017

The interest in researching corporate governance in the broader context continues unabated. The research in this area continues to be dominated by test of agency theory in advanced capitalist economies. Few researches are seen in developing countries like Nigeria. Though there have been calls for new theories to be tested in the field of corporate governance, only few have been tested, predominantly stakeholder and resource dependence theories (Barkema and Gomez-Mejia, 1998). This paper departs from previous literature in two ways. First, it tests the identity theory. Second, it uses the case study drawing empirical data from Nigeria, an emerging economy from a developing capital market to provide insights into the corporate governance mechanisms. This study explores appropriate framework and principles governing the duties and obligations of directors, auditors and secretaries. This is crucial because there is increased reliance by the stakeholders on the three actors (directors, auditors and secretaries) as it concern corporate governance both regionally and internationally. Therefore, an exploratory case study was carried out to explore the level of development of corporate governance mechanism in developing economies like Nigeria. Despite the huge challenges, issues and bottlenecks hampering good corporate governance, the study finds growth in the number of directorships, auditors and secretaries of listed companies. Also, the study reveals the code governing the responsibilities of directors; auditors and secretaries have not produced the desired result pertaining to accountability, transparency and good corporate financial reporting. Thus this adds to the body of knowledge by contributing to the corporate governance system in developing countries
Practical guidelines to formulate an operational risk appetite statement for corporate organisations: A South African perspective
Authors: Young Jacobus
Published: February 2017

Risk appetite is currently a much debated topic and a new concept being researched and implemented by various large organisations. However, currently there seems to be much confusion on this topic in terms of an overall risk appetite statement. Uncertainty exists, for example, if there must be a statement for each primary risk type the organisation faces, or should there be an overall risk appetite statement for the organisation? This article approaches a risk appetite statement from an operational risk perspective, which could serve as a platform for other risk types. Therefore, the significance of this research aims to provide guidelines to corporate organisations during the setting of a realistic operational risk appetite statement that could add value during the pursuance of business objectives within the approved tolerance levels
Salmonella daarle and Salmonella hiduddify associated with acute gastroenteritis in piglets in India
Authors: Kylla Hosterson , Dutta Tapan Kumar , Roychoudhury Parimal , Mandakini Rajkumari , Subudhi Prasant Kumar
Published: February 2017

The present study was conducted to investigate an acute gastroenteritis outbreak in an unorganized pig farm in the North Eastern Hilly Region of India. Fecal samples were collected from 20 pigs including 5 piglets, which were suffering from acute gastroenteritis and were processed for detection of E. coli, Salmonella, Clostridium sp., Rotavirus, Picobirnavirus as well as parasitic eggs and larvae by standard laboratory techniques. Virulence genes for pathogenic E. coli and Salmonella were detected by specific PCR assays. A total of 77 E. coli were isolated, all of which were found to be negative for any putative virulence genes of STEC/VTEC, ETEC, EHEC and EPEC pathotype by PCR. A total of 5 salmonellae were also isolated from 5 affected piglets, of which 1 and 4 were recorded as Salmonella daarle and Salmonella hiduddify, respectively. All the Salmonellae were positive for enterotoxin (stn) and invasion (invA) genes by PCR. In conclusion it may be stated that this is the first report of S. daarle and S. hiduddify associated with piglet diarrhoea and also first report from India with any type of enteric infection in man and animalsMicrobes and Health, December 2016, 5(1): 1-3
White Paper — Open Science in a Digital Republic — Strategic Guide
Authors: Scientific and Technical Information
Published: February 2017

These Study Review and Proposals have been designed to structure and facilitate the implementation of the Act: they therefore concur with the positions adopted by the sponsors of the White Paper Open Science in a Digital Republic, who all clearly wish to associate this new vision for research with practices that will enable it to become a reality.

As a supplementary report to the White Paper, these Guidelines aim to assist players in what are often complex procedures: researchers, technicians, publishers and users of the results of public science now need to move forward in the same spirit of discovery that characterises the major digital projects for science. First among these is the ISTEX Investments for the Future project, which is the driving force.
Financial Literacy
Authors: Valencia Álvarez Adriana Berenice , Valenzuela González Jaime Ricardo
Published: February 2017

Financial literacy is a combination of financial knowledge, attitudes and behaviors, key for making informed decisions and for solving financial problems. This descriptive study explored the applied, conceptual and procedural financial knowledge of 243 Mexican students via three financial knowledge tests. In addition, these students were surveyed about their financial behavior, their attitudes towards money, and their experience with money using a self-report questionnaire. The study aims to identify financial-education needs and gaps between school levels and systems. Therefore, the analysis focuses on the differences and similarities between two subgroups: (1) students in public and in private education, and between (2) middle school (ages 12 to 15) and high school students (ages 15 to 18). Middle school and high school students differed significantly only in their conceptual knowledge and in their financial experience, while public and private students showed statistical significant differences on their financial knowledge, behavior, attitudes and experience.
Assessing Authentic Intellectual Work in Mathematics Tasks
Authors: Rodríguez Martínez Lesly Yahaira , Pérez Martínez María Guadalupe , Mercado Salas Adriana
Published: February 2017

This paper reports an analysis of the tasks included in the Mathematical Challenges book. The analysis was based on the proposals of the Authentic Intellectual Work (AIW). The purpose of the study focuses on assessing the potential of the mathematical challenges to promote in-depth and meaningful learning through the connection with different contexts, and other features including purpose, multiple-solution pathways, construction of knowledge and higher order thinking. Participants in this study were 3 elementary school teachers, 2 mathematics specialists and the authors of this paper; they assessed the Mathematical Challenges through a questionnaire based on specific rubrics. The study used a mixed methods approach. The analysis produced two main findings. First, challenges vary in their connections to students' lives according to the context they come from. Second, almost all mathematical challenges are related to the highest levels of others AIW criteria.
Cardioembolic Stroke: A Case Study
Authors: Babkair Lisa A.
Published: February 2017

Cardioembolic stroke is a critical health condition that requires immediate intervention. Cardiac emboli are the most common type of embolism and account for 14% to 30% of all ischemic strokes. Atrial fibrillation is the most common cause of cardioembolic strokes, and its prevalence increases substantially with age. Other factors that increase the risk for cardioembolic stroke include hypertension, diabetes mellitus, hyperlipidemia, cardiac disease, and lifestyle choices. General supportive care and treatment of the acute phase and subsequent complications should be started immediately. Nurses must play an active role in screening patients for stroke subtypes, using appropriate diagnostic tools, and providing medical and nursing interventions. Nurses also play a crucial role in prevention by providing education to patients and patients’ families on how to recognize stroke signs and symptoms. This case study discusses the course of illness, treatment, and prevention strategies for patients who have suffered cardioembolic stroke due to atrial fibrillation.
Reducing Acute Kidney Injury Due to Contrast Material: How Nurses Can Improve Patient Safety
Authors: Lambert Peggy , Chaisson Kristine , Horton Susan , Petrin Carmen , Marshall Emily , Bowden Sue , Scott Lynn , Conley Sheila , Stender Janette , Kent Gertrude , Hopkins Ellen , Smith Brian , Nicholson Anita , Roy Nancy , Homsted Brenda , Downs Cindy , Ross Cathy S. , Brown Jeremiah
Published: February 2017

BACKGROUND

Acute kidney injury due to contrast material occurs in 3% to 15% of the 2 million cardiac catheterizations done in the United States each year.

OBJECTIVE

To reduce acute kidney injury due to contrast material after cardiovascular interventional procedures.

METHODS

Nurse leaders in the Northern New England Cardiovascular Disease Study Group, a 10-center quality improvement consortium in Maine, New Hampshire, and Vermont, formed a nursing task force to reduce acute kidney injury due to contrast material after cardiovascular interventional procedures. Data were prospectively collected January 1, 2007, through June 30, 2012, on consecutive nonemergent patients (n = 20 147) undergoing percutaneous coronary interventions.

RESULTS

Compared with baseline rates, adjusted rates of acute kidney injury among the 10 centers were significantly reduced by 21% and by 28% in patients with baseline estimated glomerular filtration rate less than 60 mL/min per 1.73 m2. Key qualitative system factors associated with improvement included use of multidisciplinary teams, standardized fluid orders, use of an intravenous fluid bolus, patient education about oral hydration, and limiting the volume of contrast material.

CONCLUSIONS

Standardization of evidence-based best practices in nursing care may reduce the incidence of acute kidney injury due to contrast material.
Secondary chondrosarcoma: Malignant transformation of pre-existing hereditary and non-hereditary cartilaginous lesions
Authors: Vlok Susanna C.S. , Wagener Georg W.W. , Zaharie Dan
Published: February 2017

Secondary chondrosarcoma is a malignant hyaline cartilage tumour originating from a cartilaginous precursor, either osteochondroma or enchondroma. We contrast two different cases of biopsy-proven secondary chondrosarcomas resulting from benign, pre-existing cartilaginous lesions – our aim is to contrast and compare these two benign conditions consisting of multiple cartilaginous lesions – one hereditary and the other non-hereditary – and emphasise their potential for malignant transformation.
Pearls in paediatric trauma neuroimaging reporting – What not to miss
Authors: Ramlakhan Raksha , Wieselthaler Nicky
Published: February 2017

The features of paediatric head trauma are well described. This article aims to highlight review areas and ‘do not miss’ lesions over and above the known and easily recognised injuries often sought when analysing computed tomography (CT) brains for head injury. Particular attention is paid to fractures and three-dimensional (3D) imaging. Emphasis is also placed on bridging vein thrombosis, retroclival hematomas and corpus callosum injuries.
Presentation of "Architecture and Narrativity"
Authors: Lelièvre Samuel , Inizan Yvon
Published: February 2017

Presentation of the Ricoeur's text "Architecture and Narrativity, published in that issue" (english version)
Digital Ricoeur
Authors: Taylor George H. , Nascimento Fernando
Published: February 2017

As Ricœur scholars know, the literature by and on Ricœur is vast. Material written by Ricœur that is not collected in published volumes is often difficult to locate, and even in the published volumes it is frequently a challenge to locate where Ricœur discusses a particular topic. Given the amount of his work it can be a challenge too to determine changes in his analyses over the life of his corpus. And locating secondary literature on Ricœur can be equally problematic. In response, we have been working to establish a model for how Ricœur’s corpus might be digitized so that the issues of access, keyword location, and pattern might all be addressed. To develop the model, we are starting with Ricœur’s primary texts in English and plan to expand over time to other languages and to the secondary literature on Ricœur. In the present article we discuss our model and its five steps: digital access; copyright; text preparation for digital searches and analysis; examples of digital searches and analyses; and an archive portal interface that allows users to query based on an extensible set of search variables without needing to know or access the underlying search logic. We also invite interested researchers to help assist the development of this digitization project.
Octavio Ruiz-Manjón, mi amigo
Authors: Langa Laorga Alicia
Published: February 2017

Octavio Ruiz-Manjón, mi amigo
¿De qué crisis hablamos? Algunas ideas en perspectiva histórica sobre la crisis actual del proceso de integración europea
Authors: Moreno Juste Antonio
Published: February 2017

El fin de la Guerra Fría indudablemente supone el fin de un era en Europa y posiblemente una de las principales consecuencias haya sido el agotamiento de la utopía europea como un sueño vivo a comienzos del siglo XXI. El objetivo de este artículo es comprender desde la perspectiva del historiador la influencia de la noción de “crisis” sobre el relato europeo al objeto de intentar explicar algunas de las deficiencias más comunes en el análisis político en relación con la génesis de la actual crisis del proceso de integración.
Determining Agency Theory Framework through Financial Leverage & Insider Ownership: Evidence from Pakistan
Authors: Javaid Hafiz Mustansar , Javid Snober
Published: February 2017

Sound practices of corporate governance help firms to lift their performance and bring in investors’ confidence while enabling shareholders’ rights protection, qualifying the legal requirements and spotlight the vast public image about how they are operating their business. Most of the previous literature on agency theory in Pakistan has demonstrated connection among ownership structure on firm performance, value and profitability. This study extends the literature by proposing the effect of change in leverage & insider equity ownership on agency cost mitigation. Proxy is used to measure agency cost: Expense ratio: Operating expense / annual sales. We applied “Fixed effect” method on sample of 41 non-financial firms from four economic groups listed in Pakistan Stock Exchange from the period of 2010-2014. The practical implications of the study is that those investors who desire long term performance of the firm may perhaps invested in those firms which are owned by insiders or containing acceptable amount of debt, for the reason that such firms try to maintain & continue long term performance by agency cost minimization & shareholders’ interests protections.
Problematizações, desafios e possibilidades da inserção da religiosidade/espiritualidade (R/E) no contexto hospitalar brasileiro
Authors: Silva Tiago D'Oliveira , Marques Luciana Fernandes
Published: February 2017

O Brasil é um país reconhecidamente religioso e espiritualizado, embora os censos do IBGE de 1990, 2000 e 2010 tenham apontado aumento progressivo do número daqueles que se consideram sem religião. Em comparação com outros países, também o Brasil aparece como um país de predominância religiosa. Esses números revelam que a religião é um tema de interesse para o brasileiro, que atravessa a cultura e se faz presente no cotidiano influenciando suas crenças, comportamento e visão de mundo. A partir dessas constatações, pode-se inferir que a demanda para trabalhar as intersecções da R/E nos atendimentos de saúde pode ser maior do que o esperado e maior do que os profissionais de saúde estejam preparados para lidar. Pode-se indagar se esses profissionais têm algum aprendizado formal dentro das suas formações sobre o tema da R/E e o quanto estão receptivos para lidar com religiosidades/espiritualidades diferentes da sua e talvez desconhecidas, tendo em vista a diversidade religiosa no Brasil e até a multirreligiosidade (quando a pessoa frequenta mais de uma religião simultaneamente). O objetivo deste trabalho é problematizar o tema da Religiosidade e da Espiritualidade (R/E) na área da saúde, especialmente no contexto hospitalar brasileiro.
Building Mathematics Discourse in Students
Authors: Gresham Gina , Shannon Tracy
Published: February 2017

Engaging activities and discussions within a three-station instructional approach strengthened these first graders' mathematics skills and performance.
The ‘Morning Line’: What Are the Odds That the Case You're Mediating Will Settle?
Authors: Freund James C.
Published: February 2017

I have a theory about why some mediations fail—an overly simplistic view, perhaps, but one that I've developed through years of personal experience.
The wavelength dependence of gold nanorod‐mediated optical breakdown during infrared ultrashort pulses
Authors: Davletshin Yevgeniy R. , Kumaradas J. Carl
Published: February 2017

This paper investigates the wavelength dependence of the threshold of gold nanorod‐mediated optical breakdown during picosecond and femtosecond near infrared optical pulses. It was found that the wavelength dependence in the picosecond regime is governed solely by the changes of a nanorod's optical properties. On the other hand, the optical breakdown threshold during femtosecond pulse exposure falls within one of two regimes. When the ratio of the maximum electric field from the outside to the inside of the nanorod is less then 7 (the absorption regime) the seed electrons are initiated by photo‐thermal emission, and the wavelength dependence in the threshold of optical breakdown is the result of optical properties of the nanoparticle. When the ratio is greater than 7 (the near‐field regime) more seed electrons are initiated by multiphoton ionization, and the wavelength dependence of the threshold of optical breakdown results from a combination of nanorod's optical properties and transitions in the order of multiphoton ionization. The findings of this study can guide the design of nanoparticle based optical breakdown applications. This analysis also deepens the understanding of nanoparticle‐mediated laser induced breakdown for picosecond and femtosecond pulses at near infrared wavelengths.

image
Anaerobe‐Inspired Anticancer Nanovesicles
Authors: Qian Chenggen , Feng Peijian , Yu Jicheng , Chen Yulei , Hu Quanyin , Sun Wujin , Xiao Xuanzhong , Hu Xiuli , Bellotti Adriano , Shen Qun‐Dong , Gu Zhen
Published: February 2017

Anaerobic bacteria, such as Clostridium and Salmonella, can selectively invade and colonize in tumor hypoxic regions (THRs) and deliver therapeutic products to destroy cancer cells. Herein, we present an anaerobe nanovesicle mimic that can not only be activated in THRs but also induce hypoxia in tumors by themselves. Moreover, inspired by the oxygen metabolism of anaerobes, we construct a light‐induced hypoxia‐responsive modality to promote dissociation of vehicles and activation of bioreductive prodrugs simultaneously. In vitro and in vivo experiments indicate that this anaerobe‐inspired nanovesicle can efficiently induce apoptotic cell death and significantly inhibit tumor growth. Our work provides a new strategy for engineering stimuli‐responsive drug delivery systems in a bioinspired and synergistic fashion.
Induction of Strong and Tunable Circularly Polarized Luminescence of Nonchiral, Nonmetal, Low‐Molecular‐Weight Fluorophores Using Chiral Nanotemplates
Authors: Goto Taisei , Okazaki Yutaka , Ueki Masahiro , Kuwahara Yutaka , Takafuji Makoto , Oda Reiko , Ihara Hirotaka
Published: February 2017

A new strategy is described for generating strong circularly polarized luminescence with highly tunable emission bands through chiral induction in nonchiral, totally organic, low‐molecular‐weight fluorescent dyes by chiral nanotemplate systems. Our approach allows the first systematic investigation to clarify the correlation between the circular dichroism and circularly polarized luminescence intensities. As a result, a dilute solution system with the highest circularly polarized luminescence intensity achieved to date and a dissymmetry factor of over 0.1 was identified.
Poly(p‐phenyleniminoboran): ein Bor‐Stickstoff‐Analogon von Poly(p‐phenylenvinylen)
Authors: Lorenz Thomas , Crumbach Merian , Eckert Thomas , Lik Artur , Helten Holger
Published: February 2017

Der isoelektronische und isostere Austausch ausgewählter CC‐ durch BN‐Einheiten in π‐konjugierten organischen Systemen (BN/CC‐Isosterie) hat sich als erfolgreiche Strategie zur Entwicklung BN‐dotierter polycyclischer aromatischer Kohlenwasserstoffe (PAKs) mit faszinierenden Eigenschaften und Funktionen erwiesen. Unlängst haben erste Beispiele die Nützlichkeit dieses Konzepts in der Polymerchemie gezeigt. Hier stellen wir die Synthese und Charakterisierung des ersten Poly(p‐phenyleniminoborans) vor. Dieses neue anorganisch‐organische Hybridpolymer kann als BN‐Analogon des bekannten Poly(p‐phenylenvinylens) (PPV) angesehen werden. Photophysikalische Untersuchungen am Polymer und einer Reihe von Modelloligomeren geben eindeutige Hinweise auf π‐Konjugation über die B=N‐Bindungen und eine Erweiterung der Konjugationslänge mit wachsender Kettenlänge. TD‐DFT‐Rechnungen verschaffen einen tieferen Einblick in die elektronische Struktur der neuen Materialien.
Einfluss der Wärmespeicherfähigkeit auf Heizwärmebedarf und thermischen Komfort
Authors: Schlitzberger Stephan , Kempkes Christoph , Maas Anton , Schäfers Martin
Published: February 2017

Anhand eines Einfamilienhauses und eines Mehrfamilienhauses wird mithilfe dynamisch‐thermischer Simulationsberechnungen der Einfluss der Wärmekapazität der Außen‐ und Innenbauteile auf den Nutzenergiebedarf für Heizen einerseits und den sommerlichen Temperaturkomfort andererseits aufgezeigt. Hierbei werden baupraktische Wand‐, Decken‐ und Bodenkonstruktionen jeweils in einer Ausführung in Kalksandstein (schwere Bauart) bzw. Holz (leichte Bauart) zugrunde gelegt und es werden die Fälle mit und ohne nächtliche Temperaturreduktion betrachtet. Das Wärmeschutzniveau wird dabei in drei Varianten entsprechend den Niveaus EnEV 2016, KfW‐Effizienzhaus 55 sowie KfW‐Effizienzhaus 40 gewählt. Die Nutzungsrandbedingungen entsprechen soweit möglich den Vorgaben gemäß DIN V 4108‐6, DIN V 18599‐10 und DIN 4108‐2; für die Klimarandbedingungen wird generell der Klimadatensatz TRY04 (Potsdam, Normaljahr) zugrunde gelegt.

Es zeigt sich, dass eine schwere Bauart Vorteile sowohl hinsichtlich des Nutzenergiebedarfs Heizen als auch besonders hin sichtlich des thermischen Komforts im Sommer aufweist. Die ermittelten Einsparungen an Heizwärme betragen abhängig von der Gebäudegeometrie, dem Wärmeschutzniveau und den Nutzungsrandbedingungen (Nachtabsenkung) bis zu 4 %, ein thermischer Komfort im Sommer lässt sich im Vergleich zur leichten Bauart auch ohne Kühlung relativ leicht bewerkstelligen, ebenso wie die Einhaltung der gesetzlichen Mindestanforderungen.
Assessment of knowledge of participants on basic molecular biology techniques after 5‐day intensive molecular biology training workshops in Nigeria
Authors: Yisau J. I. , Adagbada A. O. , Bamidele T. , Fowora M. , Brai B. I. C. , Adebesin O. , Bamidele M. , Fesobi T. , Nwaokorie F. O. , Ajayi A. , Smith S. I.
Published: February 2017

The deployment of molecular biology techniques for diagnosis and research in Nigeria is faced with a number of challenges, including the cost of equipment and reagents coupled with the dearth of personnel skilled in the procedures and handling of equipment. Short molecular biology training workshops were conducted at the Nigerian Institute of Medical Research (NIMR), to improve the knowledge and skills of laboratory personnel and academics in health, research, and educational facilities. Five‐day molecular biology workshops were conducted annually between 2011 and 2014, with participants drawn from health, research facilities, and the academia. The courses consisted of theoretical and practical sessions. The impact of the workshops on knowledge and skill acquisition was evaluated by pre‐ and post‐tests which consisted of 25 multiple choice and other questions. Sixty‐five participants took part in the workshops. The mean knowledge of molecular biology as evaluated by the pre‐ and post‐test assessments were 8.4 (95% CI 7.6–9.1) and 13.0 (95 CI 11.9–14.1), respectively. The mean post‐test score was significantly greater than the mean pre‐test score (p < 0.0001). The five‐day molecular biology workshop significantly increased the knowledge and skills of participants in molecular biology techniques. © 2017 by The International Union of Biochemistry and Molecular Biology, 45(4):313–317, 2017.
Simultaneous determination of eight bioactive components of Qishen Yiqi dripping pills in rat plasma using UFLC–MS/MS and its application to a pharmacokinetic study
Authors: Shao Yaping , Zhang Wen , Tong Ling , Huang Jingyi , Li Dongxiang , Nie Wei , Zhu Yan , Li Yunfei , Lu Tao
Published: February 2017

In this study, a rapid and reliable ultra‐fast liquid chromatography–tandem mass spectrometry method was developed and validated for the simultaneous determination of eight active ingredients, including astragaloside IV, ononin, tanshinol, protocatechualdehyde, protocatechuic acid, salvianolic acid D, rosmarinic acid and ginsenoside Rg1, in rat plasma. The plasma samples were pretreated by protein precipitation with acetonitrile. Chromatographic separation was performed on a Waters Acquity UPLC® BEH C18 column (1.7 μm particles, 2.1 × 100 mm). The mobile phase consisted of 0.1% aqueous formic acid (A)–acetonitrile with 0.1% formic acid (B) at a flow rate of 0.4 mL/min. Quantification was performed on a triple quadruple tandem mass spectrometry with electrospray ionization by multiple reaction monitoring both in the negative and in the positive ion mode. The lower limit of quantification of tanshinol was 2.0 ng/mL and the others were 5.0 ng/mL. The extraction recoveries, matrix effects, intra‐ and inter‐day precision and accuracy of eight tested components were all within acceptable limits. The validated method was successfully applied to the pharmacokinetic study of the eight active constituents after intragastric administration of three doses (1.0, 3.0, 6.0 g/kg body weight) of Qishen Yiqi Dripping Pills to rats.
Development and validation of a reversed‐phase high‐performance liquid chromatographic method with solid‐phase extraction for the quantification of hydrochlorothiazide in ex vivo permeation studies
Authors: Onnainty R. , Schenfeld E.M. , Longhi M.R. , Quevedo M.A. , Granero G.E.
Published: February 2017

Hydrochlorothiazide (HCT) is a diuretic used to treat hypertension. In order to study its intestinal permeation behavior applying an ex vivo methodology, a rapid, sensitive and selective reversed‐phase liquid chromatography (RP‐HPLC) method coupled with UV detection (RP‐HPLC UV) was developed for the analysis of HCT in TC199 culture medium used as mucosal and serosal solutions in the everted rat intestinal sac model. Also, analytical procedures for the quantification of HCT by RP‐HPLC with UV detection required a sample preparation step by solid‐phase extraction. The method was validated in the concentration range of 8.05 × 10−7 to 3.22 × 10−5 m for HCT. Chromatographic parameters, namely carry‐over, lower limit of quantification (1.4491 × 10−7 m), limit of detection (3.8325 × 10−8 m), selectivity, inter‐ and intraday precision and extraction recovery, were determined and found to be adequate for the intended purposes. The validated method was successfully used for permeability assays across rat intestinal epithelium applying the ex vivo everted rat gut sac methodology to study the permeation behavior of HCT.
Crystal Structures of Diaryliodonium Fluorides and Their Implications for Fluorination Mechanisms
Authors: Lee Yong‐Sok , Chun Joong‐Hyun , Hodošček Milan , Pike Victor W.
Published: February 2017

The radiofluorination of diaryliodonium salts is of value for producing radiotracers for positron emission tomography. We report crystal structures for two diaryliodonium fluorides. Whereas diphenyliodonium fluoride (1 a) exists as a tetramer bridged by four fluoride ions, 2‐methylphenyl(phenyl)iodonium fluoride (2 a) forms a fluoride‐bridged dimer that is further halogen bonded to two other monomers. We discuss the topological relationships between the two and their implications for fluorination in solution. Both radiofluorination and NMR spectroscopy show that thermolysis of 2 a gives 2‐fluorotoluene and fluorobenzene in a 2 to 1 ratio that is in good agreement with the ratio observed from the radiofluorination of 2‐methylphenyl(phenyl)iodonium chloride (2 b). The constancy of the product ratio affirms that the fluorinations occur via the same two rapidly interconverting transition states whose energy difference dictates chemoselectivity. From quantum chemical studies with density functional theory we attribute the “ortho‐effect” to the favorable electrostatic interaction between the incoming fluoride and the o‐methyl in the transition state. By utilizing the crystal structures of 1 a and 2 a, the mechanisms of fluoroarene formation from diaryliodonium fluorides in their monomeric, homodimeric, heterodimeric, and tetrameric states were also investigated. We propose that oligomerization energy dictates whether the fluorination occurs through a monomeric or an oligomeric pathway.
Das Molkonzept durch Experiential Learning
Authors: Barke Hans‐Dieter , Indriyanti Nurma Yunita
Published: February 2017

Der Einsatz des Molbegriffs wird an deutschen Schulen heftig diskutiert: an Realschulen verzichtet man oftmals auf das Stöchiometrische Rechnen, weil Lernende uninteressiert und intellektuell überfordert sind. Deshalb wird ein Weg erprobt, das „Zählen durch Wiegen“ mit Hilfe von Bonbons handlungsorientiert einzuführen und eine durch Lernende kreierte, fiktive Zähleinheit auf den Molbegriff zu übertragen. Es werden gute, aber unterschiedliche Ergebnisse in beiden Ländern festgestellt – vor allem verbessert sich die Motivationslage der deutschen Probanden.
Inhibition of α5 subunit‐containing GABAA receptors facilitated spinal nociceptive transmission and plasticity
Authors: Xue M. , Liu J.P. , Yang Y.H. , Suo Z.W. , Yang X. , Hu X.D.
Published: February 2017

Background

γ‐Aminobutyric acid (GABA) type A receptors (GABAARs) locate at both synaptic and extrasynaptic membrane, which generate phasic and tonic inhibition, respectively. In spinal cord dorsal horn, the phasic inhibition produced by transient activation of synaptic GABAARs plays an important role in the gating control over nociceptive conveyance. Although extrasynaptic GABAARs that contain α5 subunits (α5‐GABAARs) are also detectable in spinal dorsal horn, much less is known about the function of these receptors.

Methods

The C fibre‐evoked field potentials were recorded in superficial dorsal horn of spinal cord, and the effects of α5‐GABAAR inverse agonist L‐655708 on basal synaptic transmission and long‐term potentiation (LTP) of C‐fibre responses were examined. The possible changes of glutamate receptor function and pain sensitivity after α5‐GABAAR inhibition were investigated by western blot and behavioural tests.

Results

Inhibition of α5‐GABAARs by L‐655708 boosted the basal synaptic transmission and facilitated the induction of N‐methyl‐d‐aspartate subtype glutamate receptors (NMDARs)‐dependent LTP. L‐655708 was found to enhance the phosphorylation and synaptic accumulation of NMDARs and α‐Amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionic Acid receptors (AMPARs). Intrathecal L‐655708 injection also decreased the pain thresholds of intact mice in a dose‐dependent manner.

Conclusions

α5‐GABAARs were critical for the tonic inhibition of glutamatergic neurotransmission and plasticity in spinal dorsal horn.

Significance

Tonic inhibition generated by α5‐GABAARs is important for information processing. However, whether and how α5‐GABAARs regulate the conveyance of nociceptive signals in spinal cord is largely unknown. Here, we revealed a negative control by α5‐GABAARs over nociceptive transmission and plasticity.
Structural Analysis of G1691S Variant in the Human Filamin B Gene Responsible for Larsen Syndrome: A Comparative Computational Approach
Authors: P Sneha , D Kumar Thirumal , Tanwar Himani , R Siva , C George Priya Doss , Zayed Hatem
Published: February 2017

Larsen syndrome (LRS) is a rare genetic disease associated with variable manifestations including skeletal malformations, dislocations of the large joints, and notable changes in facial and limb features. Genetic variants in the Filamin B (FLNB) gene are associated with the development of LRS. We searched two literature databases (OMIM and PubMed) and three gene variant databases (HGMD, UniProt, & dbSNP) to capture all the possible variants associated with LRS phenotype, which may have an impact on the FLNB function. Our search yielded 77 variants that might impact the FLNB protein function in patients with LRS. We performed rigorous computational analysis such as conservational, biochemical, pathogenicity, and structural computational analyses to understand the deleterious effect of the G1691S variant. Further, the structural changes of the G1691S variant was compared with a null variant (G1691A) and the native protein through a molecular dynamic simulation study of 50 ns. We found that the variant G1691S was highly deleterious and destabilize the protein when compared to the native and variant G1691A. This might be due to the physicochemical changes in the variant G1691S when compared to the native and variant G1691A. The destabilization was further supported by transformation of bend to coil in variant G1691S whereas bend was retained in native and variant G1691A through molecular dynamics analysis. Our study shed light on the importance of computational methods to understand the molecular nature of genetic variants and structural insights on the function of the FLNB protein. J. Cell. Biochem. 118: 1900–1910, 2017. © 2017 Wiley Periodicals, Inc.
GD2‐targeted immunotherapy and potential value of circulating microRNAs in neuroblastoma
Authors: Gholamin Sharareh , Mirzaei Hamed , Razavi Seyed‐Mostafa , Hassanian Seyed Mahdi , Saadatpour Leila , Masoudifar Aria , ShahidSales Soodabeh , Avan Amir
Published: February 2017

Neuroblastoma (NB) with various clinical presentation is a known childhood malignancy. Despite significant progress in treatment of NB afflicted patients, high risk disease is usually associated with poor outcome, resulting in long‐term survival of less that 50%. Known as a disease most commonly originated form the nerve roots, the variants involved in NB imitation and progression remain to be elucidated. The outcome of low to intermediate risk disease is favorable whereas the high risk NB disease with dismal prognosis, positing the necessity of novel approaches for early detection and prognostication of advanced disease. Tailored immunotherapy approaches have shown significant improvement in high‐risk NB patients. It has found a link between Gangliosides and progression of NB. The vast majority of neuroblastoma tumors express elevated levels of GD2, opening new insight into using anti‐GD2 drugs as potential treatments for NBs. Implication of anti‐GD2 monoclonal antibodies for treatment of high risk NBs triggers further investigation to unearth novel biomarkers as prognostic and response biomarker to guide additional multimodal tailored treatment approaches. A growing body of evidence supports the usefulness of miRNAs to evaluate high risk NBs response to anti‐GD2 drugs and further prevent drug‐related toxicities in refractory or recurrent NBs. miRNAs and circulating proteins in body fluids (plasma and serum) present as potential biomarkers in early detection of NBs. Here, we summarize various biomarkers involved in diagnosis, prognosis and response to treatment in patients with NB. We further attempted to overview prognostic biomarkers in response to treatment with anti‐GD2 drugs.
Computational Modelling of Cough Function and Airway Penetrant Behavior in Patients with Disorders of Laryngeal Function
Authors: Hoffman Ruddy Bari , Nadun Kuruppumullage Don , Carnaby Giselle , Crary Michael , Lehman Jeffery , Ilegbusi Olusegun J.
Published: February 2017

Objective/Hypothesis

Patients with laryngeal disorders often exhibit changes to cough function contributing to aspiration episodes. Two primary cough variables (peak cough flow: PCF and compression phase duration: CPD) were examined within a biomechanical model to determine their impact on characteristics that impact airway compromise.

Study Design

Computational study

Methods

A Computational Fluid Dynamics (CFD) technique was used to simulate fluid flow within an upper airway model reconstructed from patient CT images. The model utilized a finite‐volume numerical scheme to simulate cough‐induced airflow, allowing for turbulent particle interaction, collision, and break‐up. Liquid penetrants at 8 anatomical release locations were tracked during the simulated cough. Cough flow velocity was computed for a base case and four simulated cases. Airway clearance was evaluated through assessment of the fate of particles in the airway following simulated cough.

Results

Peak‐expiratory phase resulted in very high airway velocities for all simulated cases modelled. The highest velocity predicted was 49.96 m/s, 88 m/s, and 117 m/s for Cases 1 and 3, Base case, and Cases 2 and 4 respectively. In the base case, 25% of the penetrants cleared the laryngeal airway. The highest percentage (50%) of penetrants clearing the laryngeal airway are observed in Case 2 (with −40% CPD, +40% PCF), while only 12.5% cleared in Case 3 (with +40% CPD, −40% PCF). The proportion that cleared in Cases 1 and 4 was 37.5%.

Conclusion

Airway modelling may be beneficial to the study of aspiration in patients with impaired cough function including those with upper airway and neurological diseases. It can be used to enhance understanding of cough flow dynamics within the airway and to inform strategies for treatment with “cough‐assist devices” or devices to improve cough strength.

Level of Evidence

N/A.
On mechanical waves and Doppler shifts from moving boundaries
Authors: Christov Ivan C. , Christov Christo I.
Published: February 2017

We investigate the propagation of infinitesimal harmonic mechanical waves emitted from a boundary with variable velocity and arriving at a stationary observer. In the classical Doppler effect, Xs(t)=vt is the location of the source with constant velocity v. In the present work, however, we consider a source co‐located with a moving boundary x=Xs(t), where Xs(t) can have an arbitrary functional form. For ‘slowly moving’ boundaries (i.e., ones for which the timescale set by the mechanical motion is large in comparison to the inverse of the frequency of the emitted wave), we present a multiple‐scale asymptotic analysis of the moving boundary problem for the linear wave equation. We obtain a closed‐form leading‐order (with respect to the latter small parameter) solution and show that the variable velocity of the boundary results not only in frequency modulation but also in amplitude modulation of the received signal. Consequently, our results extend the applicability of two basic tenets of the theory of a moving source on a stationary domain, specifically that (i)
for non‐uniform boundary motion can be inserted in place of the constant velocity v in the classical Doppler formula and (ii) that the non‐uniform boundary motion introduces variability in the amplitude of the wave. The specific examples of decelerating and oscillatory boundary motion are worked out and illustrated. Copyright © 2017 John Wiley & Sons, Ltd.
Chemiegeschichte: Staudingers Kautschukmodell auf dem Prüfstand
Authors: Requardt Axel
Published: February 2017

Hermann Staudinger konzipierte im Jahr 1920 seine Theorie der Makromoleküle, die sein Doktorand Jakob Fritschi von 1920 bis 1922 experimentell untersuchte. Fritschi prüfte, ob die Kautschukkolloidteilchen Moleküle oder Mizellen sind, und verwendete als Erster in einer Publikation den Begriff „Makromolekül“.
Bei den Briten abgeguckt
Authors: Osterath Brigitte
Published: February 2017

Erster Präsident der vor 150 Jahren gegründeten Deutschen Chemischen Gesellschaft war August Wilhelm Hofmann. Die Idee für eine chemische Gesellschaft brachte er aus London mit, wo er 20 Jahre gelehrt hatte und sehr beliebt war.
Workshop für junge Wissenschaftler im tunesischen Hammamet
Authors: Hopf Henning , Limbach Hans , Ellouze Mohamed
Published: February 2017

Bereits zum sechsten Male gab es einen von GDCh und Alexander‐von‐Humboldt‐Stiftung unterstützten Workshop für junge Wissenschaftler aus arabischen Ländern: Dieses Mal fand die zweitägige Veranstaltung im September 2016 in Hammamet statt, einem Ferienort in Tunesien.