bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluorescence Spectroscopy in Process Analytical Technology (PAT): Simultaneous Quantification of Two Active Pharmaceutical Ingredients in a Tablet Formulation
Authors: Warnecke Solveig , Rinnan Åsmund , Allesø Morten , Engelsen Soren B.
Published: March 2015

Many pharmaceuticals include highly potent active pharmaceutical ingredients (API), which only require a small dosage to obtain the desired therapeutic effect. This leads to a challenge for quantification of the API using process analytical technology, since the standard nondestructive measurement technique, near-infrared spectroscopy, is not able to quantify below 1% (weight/weight (w/ w)) API content. In formulations with more than one API, this challenge is further increased. The purpose of this study is to scrutinize the potential of fluorescence spectroscopy for the simultaneous quantification of two APIs: flupentixol (FLU) in low dosage (0.208–0.625% w/w free base) and melitracen (MEL) (4.17–12.5% w/w free base) in a tablet formulation. Despite internal quenching between the ingredients and the two APIs, this paper demonstrates that it is possible to establish calibrations using partial least squares (PLS) regression on unfolded fluorescence landscapes with a root mean square error of prediction and relative error of 0.038% (w/w) and 9.1%, for FLU and 0.344% (w/w) and 4.1% for MEL, respectively.
Independent Component Analysis-Based Algorithm for Automatic Identification of Raman Spectra Applied to Artistic Pigments and Pigment Mixtures
Authors: Gonzáiez-Vidal Juan José , Pérez-Pueyo Rosanna , Soneira Maria José , Ruiz-Moreno Sergio
Published: March 2015

A new method has been developed to automatically identify Raman spectra, whether they correspond to single- or multicomponent spectra. The method requires no user input or judgment. There are thus no parameters to be tweaked. Furthermore, it provides a reliability factor on the resulting identification, with the aim of becoming a useful support tool for the analyst in the decision-making process. The method relies on the multivariate techniques of principal component analysis (PCA) and independent component analysis (ICA), and on some metrics. It has been developed for the application of automated spectral analysis, where the analyzed spectrum is provided by a spectrometer that has no previous knowledge of the analyzed sample, meaning that the number of components in the sample is unknown. We describe the details of this method and demonstrate its efficiency by identifying both simulated spectra and real spectra. The method has been applied to artistic pigment identification. The reliable and consistent results that were obtained make the methodology a helpful tool suitable for the identification of pigments in artwork or in paint in general.
Coupled Turbidity and Spectroscopy Problems: A Simple Algorithm for the Volumetric Analysis of Optically Thin or Dilute Two-Phase Systems
Authors: Dent Paul , Deng Bin , Goodisman Jerry , Chaiken Joseph
Published: March 2015

We report an algorithm for measuring the phase volume fraction and solute concentration of a two-phase system, applicable to either optically thin or optically dilute spatially homogeneous systems. Probing light is directed into the sample, and the elastically scattered light (EE) is collected as one signal and the inelastically scattered light (IE) collected as another signal. The IE can be pure fluorescence or Raman or an unresolved combination of the two. As the IE and the EE are produced by fundamentally different processes, they are independent. The algorithm, derived from radiation transfer theory, shows that phase volume and concentration are linear functions of the EE and IE. The parameters are derived from a training set. We present examples of how the algorithm performs when the assumption of spatial homogeneity is violated and when light-induced photochemistry causes changes in the IE. Although this is a generally valid algorithm with many potential applications, its use is discussed briefly in the context of blood and tissue analysis since the algorithm was originally designed for noninvasive in vivo probing of human skin.
‘Transatlantic connection’: K-pop and K-drama fandom in Spain and Latin America
Authors: Madrid-Morales Dani , Lovric Bruno
Published: March 2015

The global circulation of Asian cultural products has been on a constant rise since the 1990s. However, the arrival to Spanish-speaking audiences is a more recent phenomenon, one that is linked to the consolidation of web-based tools for consumption, distribution and discussion of cultural artefacts. The different stages in which Hallyu, or the ‘Korean Wave’, reached different countries determined the intensity of scholarly interest in the phenomenon. If the research gap between Asia and Europe is wide, the later arrival to Spain and Latin America means that studies on the reception of Korean popular culture, including those dealing with fandom, are quasi-non-existent. This article is a first attempt at mapping the demographics of K-pop and K-drama fans in the Spanish-speaking world, through an analysis of an online survey. Drawing from the uses and gratifications approach in mass communication research, we discuss fans’ appropriation of K-pop, describe their shared iconography and analyse the peculiarities of male fans by studying their self-narratives. We conclude with a discussion on the need for studies of fandom to transcend national boundaries as exemplified by the advent of a ‘transatlantic connection’ linking fans in Spain and in Latin America via South Korea.
Queering spectatorship in K-pop: The androgynous male dancing body and western female fandom
Authors: Oh Chuyun
Published: March 2015

Employing performance studies and queer studies, this article explores the subversive nature of western female fandom’s consumption of male dancing bodies in Korean pop (K-pop) culture. By offering close readings of fan-made compilation videos and analysing fans’ comments on YouTube, this article analyses how K-pop male idols’ androgynous gender fluidity provides a space for queering female desire against normative white masculinity. Through video editing, fans ‘choreograph’ their desire by fetishizing K-pop male dancers’ specific body parts and movements and transform themselves from displayed objects to subjects of the gaze. Moreover, through active engagement online, fans transcend their status from spectators to performers who actively enact alternative sexualities and gender roles in a public space. K-pop male singers’ gender performativity is significant, as it challenges rigid gender binaries in western culture – homosexuality/heterosexuality, masculine/feminine body and behaviour, and masculinized gaze/feminized object – as embodiments of hybridized male femininity, which this article calls liminal masculinity.
Reshaped, reconnected and redefined: Media portrayals of Korean pop idol fandom in Korea
Authors: Kim Ju Oak
Published: March 2015

This article examines how Korean pop (K-pop) idol fans develop their public image through the construction of participatory culture. K-pop idol fans, mostly teenaged girls, have long-provoked criticism in Korean society due to their fanatic behaviours. In the late 2000s, however, the transnational popularity of K-pop idol groups encouraged the public to reconsider the negative stereotype of K-pop idol fandom. This social atmosphere is indebted to news journalism, which sheds light on the contribution of fan communities in the K-pop music industry. Donation activities are one of the main items that journalists focus on in covering idol fan communities. Through an analysis of news articles, this article argues that Korean idol fandom strategically employs donation activities in order to reshape stereotypes about idol fandom, reconnect with the public and redefine the notion of idol fandom in Korean society.
From Holy Land to ‘Hallyu Land’: The symbolic journey following the Korean Wave in Israel
Authors: Lyan Irina , Levkowitz Alon
Published: March 2015

The majority of academic literature on Hallyu, or the Korean Wave, focuses on its acceptance in the geographically and culturally proximate societies in Asia and the economically wealthy markets of North America. Very little attention has been given to other regions such as Africa, South America and the Middle East. Thus, looking at the Israeli case study allows us to examine how Korean culture is being accepted in non-Asian, non-western and non-English contexts. The most salient characteristic of Hallyu fans in Israel is that the majority of them have never been to Korea. They experience Korean culture mostly through Korean TV dramas, and fandom itself becomes a cultural journey between the known and the unknown. This journey resembles the practice of pilgrimage, e.g. an emotional exploration of new places accompanied by a deep sense of fulfilment. Korean culture is perceived as an exotic and distant ‘other’. At the same time, this ‘other’ is domesticated by local fan communities and serves as a means to connect one’s own identity with Hallyu’s ‘promised land’. Based on media and discourse analysis, an online survey and interviews with Israeli fans, this article examines the popularity of the Korean Wave in Israel and its impact on Korea’s image among fans. The article also explores the inner world created among fans of the Korean world, the formation of a fan community and their fictional ‘Hallyu Land’.
Acknowledging a ‘Missing History?’
Authors: Doyle Susan
Published: March 2015

A unique grassroots project is under way to write the first-ever textbook on the History of Illustration. The effort, which benefits from a base of over 30 writers internationally, is backed by a consortium of more than 60 educators, researchers, curators and illustration practitioners collaborating under the aegis of the History of Illustration Project (HIP). The volume, now in development with Fairchild Books (a Bloomsbury imprint), evolved initially through an online conversation about the need for more critical assessment of illustration and its history. Many of the points of that debate are detailed in the article that follows. The summary rationale for the HIP textbook (of which I am lead editor) is to expand the art historical investigation of illustration and address its synergistic relationship to history, science, visual culture and literature.
Alchemy, image and text: The waning of alchemy and the decline of visual discourse in the late Renaissance
Authors: Holme Adrian
Published: March 2015

From its obscure origins in antiquity the alchemical tradition enjoyed a late flowering in seventeenth-century Europe with the appointment of alchemists at European Courts and a profusion of alchemical publications within the rapidly expanding output of printed books. Works, such as Michael Maier’s Atalanta fugiens (1618) and Robert Fludd’s Utriusque cosmi (1617, 1621) incorporated fine engravings, with imagery that reflected the Renaissance spirit of synthesis, resemblance, analogy and allegory, and the deployment of a widely accepted range of symbols and emblems. Microcosm and Macrocosm, matter and spirit, the human and the scientific were presented by Fludd and others as a unified cosmos, linked by complex systems of analogy and resemblance, within a framework of NeoPlatonism and Christianity. Alchemical literature employed a balance of text and image, in which visual argument, using analogy, resemblance, emblem and allegory, complemented text. The question of why this system gave way, in the late seventeenth century and ensuing Enlightenment to modern scientific and other serious discourse, progressively stripped of images, is discussed with reference to the writings of Francis Bacon, Edmund Burke, Ernst Gombrich, WJT Mitchell and Marshall McLuhan. The enduring influence of alchemy upon visual artists, from William Blake to Yves Klein and Anselm Kiefer, reflects a continuing concern with the integration of the material and the spiritual, and challenges a linguistics-based semiotics as well as an excessively reductionist science.
Illustrating Elizabeth Bennet and Mr Darcy: Jane Austen’s Pride and Prejudice
Authors: Newman Emily L.
Published: March 2015

Throughout the nineteenth century, Jane Austen’s Pride and Prejudice (1813) was repeatedly picked up for publication; however, it was slow to be illustrated. Austen tells the story of the Bennet family, as the five girls in the family come of age and are seeking husbands. Mr Darcy and Elizabeth Bennet become the titular characters, and have inspired millions of readers for them to root for their union. The book, of which the countless film adaptations attest, has found a lasting audience. Through an examination of the publishers and the various artists that worked on the editions, I want to examine how the book epitomized trends in the publishing industry. Key publishers like Richard Bentley and J. M. Dent, hired some of the most important illustrators of the time, including John Gilbert, John Proctor, C. E. Brock, Hugh Thomson and Chris Hammond. Through an examination of the artists and the illustrations, we can begin to examine the popularity of the book and why this endearing novel’s popularity is so lasting. Focusing on characters, fanciful clothing and revelatory conversations, these illustrators contributed to the books’ position as one of the most popular romance novels of the century.
The marks and modes of modernism: The Puffin Picture Books (1940–1965)
Authors: Cory-Wright Harriet
Published: March 2015

Casting a proximate net across concurrent artistic, social and political activity in relation to the Puffin Picture books reveals a cultural codification that structured the creation of the populist, pedagogical and practical print practices that materalise in the books. In framing and forming a greater understanding around the circumstances of conception of the books has formed a complex multiplicity of interior views that at once supports, calibrates and challenges familiar early twentieth-century artistic and cultural narratives.
Episódios hidrometeorológicos extremos noticiados no distrito de Coimbra durante a segunda metade do século XIX
Authors: Nunes Adélia , Lourenço Luciano , Pinho João , Bento-Gonçalves António , Vieira António
Published: March 2015

Identificar as áreas que sofreram eventos históricos constitui o primeiro passo para uma análise integral do risco. Com o presente trabalho pretende-se analisar a incidência espacial de episódios hidrometeorológicos extremos, no decurso da segunda metade do século XIX, no distrito de Coimbra. Para o efeito, recorreu-se aos jornais da época como fontes de informação fidedigna, uma vez que nesse período não existiam recolhas sistemáticas dos principais elementos do sistema hidroclimático.
Desastres naturais de origem hidro-geomorfológica no baixo Mondego no período 1961-2010
Authors: Tavares Alexandre O. , Barros Leandro , Santos Pedro P. , Zêzere José L.
Published: March 2015

Apresenta-se uma base de dados de desastres naturais de origem hidro-geomorfológica reportados na imprensa escrita local, para a região do Baixo Mondego, no período 1961-2010. Os resultados salientam espacialmente a relevância das inundações em espaço urbano e das cheias progressivas em espaços de interface urbano/rural, assim como os movimentos de massa associados a infraestruturas viárias. A distribuição temporal das ocorrências mostra a diminuição dos impactos por cheias progressivas, com incremento dos relacionados com cheias rápidas.
Inducing gene expression by targeting promoter sequences using small activating RNAs
Authors: Wang Ji , F. Place Robert , Portnoy Victoria , Huang Vera , Kang Moo Rim , Kosaka Mika , Chung Ho Maurice Kwok , Li Long-Cheng
Published: March 2015

Vector-based systems comprised of exogenous nucleic acid sequences remain the standard for ectopic expression of a particular gene. Such systems offer robust overexpression, but have inherent drawbacks such the tedious process of construction, excluding sequences (e.g. introns and untranslated regions) important for gene function and potential insertional mutagenesis of host genome associated with the use of viral vectors. We and others have recently reported that short double-stranded RNAs (dsRNAs) can induce endogenous gene expression by targeting promoter sequences in a phenomenon referred to as RNA activation (RNAa) and such dsRNAs are termed small activating RNAs (saRNAs). To date, RNAa has been successfully utilized to induce the expression of different genes such as tumor suppressor genes. Here, we describe a detailed protocol for target selection and dsRNA design with associated experiments to facilitate RNAa in cultured cells. This technique may be applied to selectively activate endogenous gene expression for studying gene function, interrogating molecular pathways and reprogramming cell fate.
Behavioral strategies of automated vehicles in critical right of way
situations on intersections
Authors: Stoff Alexander , Winner Hermann
Published: March 2015

This paper analyzes and evaluates alternative options for action and earliest possible dates for intervention for an automated safety
function to avoid or mitigate collisions in priority situations in which the right of way regulations are violated by the crossing road
users. Based on a simulation of the collision avoidance strategies, the potential safety benefits could be predicted.
Bosch's approach toward automated driving
Authors: Becker Jan , Kammel Sören , Pink Oliver , Fausten Michael
Published: March 2015

Advanced driver assistance systems already help drivers reach their destinations safely and more comfortably. Future systems will
evolve from driver assistance over highly automated vehicles to fully automated driving. With an increasing level of automation,
automated functions will reduce the driver's burden more and more, thereby creating space for productivity, communication or
entertainment while driving. In this article we outline our roadmap for future automated vehicles, assess the key challenges for
introduction and give an overview of the major algorithmic components.
Einführungsstrategie des Automatischen Fahrens
Authors: Bartels Arne , Ruchatz Thomas
Published: March 2015

Dieser Artikel adressiert die klare Definition von Begrifflichkeiten für die unterschiedlichen Stufen der Automatischen Fahrzeugführung. Er illustriert eine stufenweise Einführungsstrategie ausgehend von teilautomatischen Funktionen (Stau- & Park-Assistent), gefolgt von automatischen Funktionen, bei denen sich der Fahrer unter bestimmten Voraussetzungen von der Fahraufgabe abwenden darf (Stau-Chauffeur, Autobahn-Chauffeur). Ebenfalls aufgezeigt werden technische Herausforderungen sowie Status und Weiterarbeit zur Anpassung der rechtlichen Rahmenbedingungen.
Pointwise Computation in an Ill-Posed Spherical Pseudo-Differential Equation
Authors: Pereverzyev Sergei V. , Tkachenko Pavlo
Published: March 2015

In the present paper, we consider the approximation of the solution of an ill-posed spherical pseudo-differential equation at a given point. While the methods for approximating the whole solution are well-studied in Hilbert spaces, such as the space of square-summable functions, the computation of values of the solution at given points is much less studied. This can be explained, in particular, by the fact that for square-summable functions the functional of pointwise evaluation is, in general, not well defined. To overcome this limitation we adjust the regularized least-squares method of An, Chen, Sloan and Womersley [Siam J. Numer. Anal. 50 (2012), no. 3, 1513–1534]
by using a special a posteriori parameter choice rule. We also illustrate our theoretical findings by numerical results for the reconstruction of the solution at a given point.
Using Stepping Stones to Enter Distant Export Markets
Authors: Lejour Arjan , Creusen Harold
Published: March 2015

This paper analyses firms’ export entry decisions and their subsequent expansion to other export markets using Dutch firm-level international transaction data. In particular new exporters increase quickly the distance between their export markets and their home country. They are also going to export to countries in which the institutional and regulatory quality is lower. We show that firms follow a stepping stone approach for learning to export and to enter distant markets. The probability to enter a market at 1,000 km from the Netherlands increases by about 25% if the firm already exports to a market at 500 km from the new one.
Economic Sector Choices of Mexican Migrants to the USA: Evidence from the 2011 EMIF Border Survey
Authors: de Oliveira André Rossi , Wooster Rossitza B.
Published: March 2015

This paper investigates the economic sector choices of Mexican labor migrants who intended to cross the US border in 2011 using data from the EMIF Norte Border Survey. We identify migrants according to prior work experience and intended sector of work in an effort to determine what demographic and socioeconomic characteristics explain economic sector mobility. We begin by estimating a probit model with sample selection to identify migrant characteristics that explain differences between industry of employment at place of origin and the intended sector of work at their destination. We find that sector mobility is significantly more likely for migrants who are documented and those with higher educational attainment, specifically, spoken English skills. The probability that prior and intended sectors of work coincide is significantly higher for migrants who are male, married, from large households, have family in the USA and earned a higher wage prior to migration. We also estimate a multinomial probit of the choice of sector and find that work sector prior to migration is more likely to match intended sector in the agriculture, construction, transportation and trade industries and significantly less likely to match in the services sector relative to other occupational categories.
Evaluation of Genotoxic and Inhibitory Effects of Invasive Weed Wild Poinsettia (Euphorbia heterophylla Linn.) in Sunflower
Authors: Safahani Langeroodi Ali Reza , Dadgar Teena , Kamkar Behnam , Teixeira da Silva Jaime A.
Published: March 2015

Determining the mode of action of allelochemicals is one of the challenging aspects in the allelopathic studies. In this research, the methanolic extracts of wild poinsettia (Euphorbia heterophyllaLinn.) at different concentrations (0, as untreated control, 8%, 12% and 16%) were tested for genotoxic and inhibitor activity on morphological, biochemical and molecular traits of sunflower (Helianthus annuusL.). Seedling emergence was reduced with wild poinsettia leaf extracts in sunflower. Leaf extracts of wild poinsettia decreased chlorophyllaandblevels and consequently the soluble sugar content was proportional to the increase in the concentrations of the leaf leachates. Some changes occurred in random amplification of polymorphic DNA (RAPD) profiles, profiles of protein bands and total soluble protein of germinated treated seed. These included variation in band intensity, loss of bands and appearance of new bands compared with control. Increased concentration of extracts caused increasing the total soluble protein content, decreasing genome template stability (GTS) value and increasing polymorphism values, the results indicated that they were dose dependent. For instance, the highest and lowest amounts of GTS were observed in 8% and 16%, respectively. In a dendrogram constructed based on genetic similarity coefficients, the treatments were grouped into two main clusters: (a) 8%, 12% and 16% dose clustered together and (b) untreated control grouped alone. Also, we concluded that the basis of interaction between plants, like allelopathy, may be related with genotoxic effects.
Knowing the Parasite: Biology and Genetics of Orobanche
Authors: Delavault Philippe
Published: March 2015

Due to their forms and colors, parasitic plants are most often considered to be botanical curiosities. However, in some cases, these are proved to be also deadly pests with the capacity to exploit other plants. Among the obligate root parasitic weeds, the holoparasites that are devoid of chlorophyll and thus unable to carry out photosynthesis totally rely on their hosts for their water, mineral, and carbohydrate supplies. Members of the genus Orobanche and Phelipanche, belonging to the Orobanchaceae family (the broomrape family), are thus the final result of this evolutionary transition from autotrophism to heterotrophism. The underlying process of this trophic exploitation, governed by a fine-tuned molecular dialogue between both partners, is an extraordinary example of adaptive plant biology operated by these parasitic organisms in the course of evolution. This transition is associated with remarkable morphological and physiological adaptations, such as the requirement for the seeds to germinate to perceive molecules produced by host roots, the development of a novel organ, the haustorium, which invades host tissues and establishes a physiological continuum between the parasite and the host, the establishment of a sink strength required for translocation of host resources, the loss of photosynthesis, and a reduced leaf and root architecture.
Characterization of technical lignins by NMR spectroscopy: optimization of functional group analysis by 31P NMR spectroscopy
Authors: Korntner Philipp , Sumerskii Ivan , Bacher Markus , Rosenau Thomas , Potthast Antje
Published: March 2015

31P nuclear magnetic resonance (NMR) based on the derivatization reagent 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane is a common approach for the hydroxyl group determination of lignins, but the results are sometimes less reproducible compared to other methods. In the present work, common pitfalls in 31P NMR analysis of kraft lignin (KL) and lignosulfonates (LS) are addressed and the results are compared to those obtained by 1H NMR spectroscopy. Several experimental parameters are revisited in terms of the reliability of the obtained data, such as the choice of relaxation delay, internal standards, and the best solution technique for the 31P NMR analysis of LS. For the first time, 31P NMR data of LS are presented based on a new dissolution protocol. The analytical data of a set of lignins consisting of three KLs, one LS, and one milled wood lignin are presented based on the optimized 31P NMR approach.
Opportunistic feeding by the little yellow-shouldered bat Sturnira lilium (Phyllostomidae, Stenodermatinae) in northern Guatemala: a comparative approach
Authors: Kraker-Castañeda Cristian , Cajas-Castillo José Octavio , Lou Salvador
Published: March 2015

During simultaneous surveys in northern Guatemala, we studied the feeding habits of frugivorous bats. We found that
Serum tryptophan, kynurenine, phenylalanine, tyrosine and neopterin concentrations in 100 healthy blood donors
Authors: Geisler Simon , Mayersbach Peter , Becker Kathrin , Schennach Harald , Fuchs Dietmar , Gostner Johanna M.
Published: March 2015

Formation of neopterin, a biomarker of the activated human immune system, is linked with tryptophan (TRP) and phenylalanine (PHE) metabolism. To obtain normal values, in this study, serum concentrations of neopterin as well as of TRP, PHE and their respective metabolites kynurenine (KYN) and tyrosine (TYR) were investigated in 100 successive blood donor serum specimens from the University Clinics of Innsbruck, Austria. In addition, nitrite concentrations were determined. Donors had passed anamnestic examination at entry and were therefore considered as healthy. The mean age of participants was 49±11.4 (mean±SD) years; 18% were older than 60 years. Both genders were included in the analysis. Neopterin concentrations measured by enzyme-linked immunosorbent assay were 5.9±1.6 nmol/L (mean±SD). Levels of amino acids and metabolites were determined by HPLC. Mean KYN and TRP concentrations were 1.78±0.42 μmol/L and 67.4±10.2 μmol/L, respectively. KYN to TRP ratio (KYN/TRP), an estimate for the activity of tryptophan-degrading enzyme indoleamine 2,3-dioxygenase, was 26.7±6.2 μmol/mmol. Mean PHE and TYR concentrations were 65.2±11.1 μmol/L and 90.6±22.9 μmol/L. PHE to TYR ratio (PHE/TYR), an estimate for the activity of PHE-converting enzyme phenylalanine hydroxylase, was 0.75±0.14 μmol/μmol. Nitrite concentrations, estimated by Griess-Ilosvay reagent, were 44.9±32.0 μmol/L. Males were taller and heavier than females (both p<0.01), but body mass index did not differ. Males presented with significantly higher TRP and TYR concentrations than females (both p<0.05). There existed significant correlations between neopterin and KYN (rs=0.368), KYN/TRP (rs=0.453), TYR (rs=–0.267; all p<0.01) and PHE/TYR (rs=0.236; p<0.05) concentrations. Data indicate that also in a population of healthy individuals an association exists between “low-grade” immune activation as is indicated by slightly higher neopterin concentrations and biochemical alterations in the amino acid metabolism. Although minor, such changes may interfere with psychoneuroimmunological regulatory networks and thus be of clinical relevance.
Genetic associations of leukoaraiosis indicate pathophysiological mechanisms in white matter lesions etiology
Authors: Lin Qing , Huang Wen-Qing , Tzeng Chi-Meng
Published: March 2015

Leukoaraiosis (LA), also called white matter lesions (WMLs) and white matter hyperintensities (WMHs), is a frequent neuroimaging finding commonly seen on magnetic resonance imaging brain scans of elderly people with prevalence ranging from 50% to 100%. Although it remains asymptomatic, LA is not considered to be benign, and it is showed to be related to a host of poor clinical outcomes and increases the risk of disability, dementia, depression, stroke, and the overall morbidity and mortality. Pathologically, LA is characterized by loss of myelin and axons, patchy demyelination, and denudation of ependyma in regions of WMH. Age and hypertension are the most importantly established risk factors for LA. However, the precise pathogenic mechanisms remain unclear. Together with the previous findings, our recent genetic results strongly supported that LA is associated with immune response and neuroinflammation. Therefore, we confidently hypothesized that LA was not only a common neuroimaging phenomenon in the elderly but also an emerging neuroinflammatory disorder in the central nervous system. This article focusing on neuroimaging classification, genetics basis, and putative molecular mechanism introduced the basic knowledge and current status of LA and put forward some of our research ideas and results from our molecular genetics research, which may pave the way for deciphering the putative pathogenic mechanism, risk factor, epigenetic index, and its application in diagnostic agents or drug target for prevention and treatment. Thus, it could provide clinicians and researchers with a specific and modern overview of LA to enable the understanding of recent progress and future directions in this illness.
The distribution of random motion with Erlang-3 sojourn times
Authors: Kolomiiets Tamila , Pogorui Anatoliy A. , Rodríguez-Dagnino Ramón M.
Published: March 2015

In this paper, we study a one-dimensional random motion with switching process having an Erlang-3 distribution for the sojourn times. We obtain the solution of the associated hyperbolic PDE of sixth order through algebraic techniques.
Synthesis, structure and thermal study of a new 3-aminopyrazine-2-carboxylate based zinc(II) coordination polymer
Authors: Karmakar Anirban , Hazra Susanta
Published: March 2015

A two-dimensional coordination polymer [Zn(L)2]n (1) (L = 3-aminopyrazine-2-carboxylate) synthesized from the solvothermal reaction of zinc(II) salt with 3-aminopyrazine-2-carboxylic acid (HL) is described. Compound 1 has been characterized by single X-ray diffraction, IR spectra and thermogravimetric analyses. Crystal structure analysis reveals that each hexacoordinated zinc(II) center adopts a distorted octahedral geometry occupied by three Ocarboxylate and three Npyrazine atoms. The L– ligand binds the metal cation by means of a pyrazine N-atom and one, or both, carboxylate O-atoms. A three-dimensional supramolecular associate in the crystal lattice of 1 has been stabilized by a number of non-covalent interactions. The IR spectroscopic and TGA properties are investigated in this work. Topological analysis of the two-dimensional network has been also discussed.
Massenspektrometrische Untersuchung der Vorgänge beim Verdampfen von Indiumarsenid
Authors: Gutbier H. B.
Published: March 2015

InAs wurde auf etwa 1000°K erhitzt und die Verdampfungsprodukte massenspektrometrisch analysiert. Es wurde festgestellt, daß das Arsen fraktioniert in Form von As4- und As2-Molekülen verdampft. Der Verdampfungsvorgang kann in drei Zeitabschnitte eingeteilt werden: 1. Sublimation von Arsen aus festem InAs, dabei Ausbildung einer mit Indium angereicherten flüssigen Phase an der Oberfläche; 2. Verdampfen des Arsens aus der flüssigen Phase unter fortschreitender Auflösung des festen InAs-Kristalles und 3. Verdampfen des in flüssigem Indium vorhandenen restlichen Arsens mit exponentiell abklingenden Verdampfungsraten. Aus der Temperaturabhängigkeit der Verdampfungsrate von As4 bzw. As2 wurde eine Aktivierungsenergie der Verdampfung von 88 ± 5 bzw. 78 ± 5 kcal pro Mol bestimmt.
Erlaubte und verbotene Gebiete bei der Bewegung elektrisch geladener Teilchen in axial-symmetrischen Magnetfeldern
Authors: Fisser H. , Kippenhahn R.
Published: March 2015

The trajectories of a charged particle in a magnetic field of rotational symmetry can be characterized by their two integrals of motion: the kinetic energy I2
2 and the generalized angular momentum I1. Orbits with different values of I1 and I2 correspond to different points in the I1 — I2-plane. By the aid of this I1 — I2-diagram we easily can get a survey of the allowed and forbidden regions in the meridional plane. In another diagram the boundaries of these regions are transformed into straight lines. Both methods are applied to the field of a magnetic dipole and to that of a circular line-current. By the example of the circular current it is shown how the problem of the so-called particle-loss can be attacked.
Die Bewegung geladener Teilchen im Magnetfeld eines geraden stromdurchflossenen Drahtes
Authors: Hebtweck F.
Published: March 2015

The motion of a charged particle in the magnetic field of a straight electric line current of infinite length is investigated. Using the numerical solutions of the equations of motion the drift velocity of the particle along the wire is calculated. For small particle energies it turns out to be in agreement with ALFVÉN'S approximation. Also the limits of the region to which the particle is confined are calculated for different values of the particle energy and its angular momentum.
Berechnung des Einflusses der Anisotropie und eines zusätzlichen Magnetfeldes auf den elektrischen Durchschlag mit Anwendung auf Germanium
Authors: Frie Wolfgang
Published: March 2015

Es werden die von FRANZ1 angegebenen Formeln auf den elektromagnetischen Fall erweitert und für Germanium ausgewertet. Die Formeln für die Erhöhung der Durchschlagsfeldstärke durch das Magnetfeld lassen sich mit den von FINKE 2 gemessenen Kurven vergleichen. Sie liefern Aussagen über die Richtungsabhängigkeit des Effektes. Die Formeln lassen sich durch einen verhältnismäßig einfachen Formalismus gewinnen.
Über das Verhalten von n-Ge-Einkristallen im Temperaturgebiet des flüssigen Heliums.
Authors: Finke Günter , Lautz Günter
Published: March 2015

Nach theoretischen Betrachtungen von CONWELL und MOTT soll der Übergang vom normalen Leitungsmechanismus eines Halbleiters zur Störbandleitung im Gebiet tiefster Temperaturen durch eine Kompensation der Störstellenarten des Kristalls begünstigt werden. In der vorliegenden Arbeit wird durch Messungen der Temperaturabhängigkeit des elektrischen Widerstandes und des HALL-Effektes für kleine elektrische Felder an n-Ge-Einkristallen unterschiedlicher Störstellenstruktur diese theoretische Aussage auch experimentell belegt.

Die oberhalb einer bestimmten elektrischen Feldstärke UD von einigen Volt/cm für Meßtemperaturen unter 10°K beobachtete reversible Abnahme des elektrischen Widerstandes und der HALL-Konstanten in Abhängigkeit vom angelegten Feld kann bei normalem Leitungsmechanismus mit einer Ladungsträgervervielfachung durch Stoßionisation neutraler Störstellen gedeutet werden. Diese Erklärung wird insbesondere durch die Abnahme der „Durchschlagsfeldstärke“ UD mit zunehmender Beweglichkeit der Ladungsträger und durch die Zunahme von UD in einem äußeren Magnetfeld gestützt. Quantitativ können durch die Behinderung der Stoßionisation in einem Magnetfeld außergewöhnlich hohe Widerstandsänderungen von 10 000% bei 300 Gauß für elektrische Feldstärken U ≈ UD beobachtet werden. Im Bereich überwiegender Störbandleitung wird zur Deutung der Feldstärkeabhängigkeiten des Widerstandes und des HALL-Effektes nach SCHOTTKY ein neuer Mechanismus der „Ionisierung“ von Elektronen im Störband benutzt.
Theorie der Kleinwinkelstreuung von Röntgen-Strahlen und Neutronen durch innere Spannungen in festen Körpern, insbesondere durch Versetzungen
Authors: Seeger Alfred , Kröner Ekkehart
Published: March 2015

Die von Versetzungen herrührende Kleinwinkelstreuung, die bisher als Integral über das Dilatatationsfeld der Versetzungen (und anderer Fehlstellen) ermittelt werden mußte, wird (soweit sie sich nach der linearen Elastizitätstheorie behandeln läßt) als Integral über die Versetzungsdichte dargestellt. Für Versetzungslinien (sog. singuläre Versetzungen) reduziert sich dieses Integral auf ein entlang der Versetzungslinien zu erstreckendes Linienintegral, mit dessen Hilfe die Rechnungen über die Kleinwinkelstreuung von Versetzungen sehr vereinfacht werden. Als Beispiel wird die Kleinwinkelstreuung durch kreisförmige Stufenversetzungsringe behandelt. Solche Ringe können durch die Kondensation von Leerstellen in Kristallen entstehen und spielen neuerdings eine Rolle bei der Diskussion der Vorgänge in abgeschreckten Metallen.
Exakte Berechnung von Franck-Condon-Integralen
Authors: Wagner Max
Published: March 2015

Bei optischen und strahlungslosen Übergängen zwischen Elektronenzuständen an einem Kristallstörzentrum werden die Ruhelagen der Gitteroszillatoren (d. h. die Nullpunkte der Normalkoordinaten) verschoben. Der Oszillatoranteil der FRANCK-CONDON-Integrale solcher Übergänge wird exakt berechnet, zunächst unter der Annahme, daß die Oszillatorfrequenzen sich bei dem Übergang nicht ändern. Diese Integrale können durch ein Laguerresches Polynom dargestellt werden. Sodann werden FRANCK-CONDON-Integrale behandelt, die auftreten, wenn man die Abhängigkeit der Wellenfunktion des Störstellenelektrons von den Gitterschwingungen in erster Näherung berücksichtigt. Sie können auf die Integrale der nullten Näherung zurückgeführt werden. Schließlich werden noch solche FRANCK-CoNDON-Integrale untersucht, die sich ergeben, wenn man die Änderung der Oszillatoreigenfrequenzen beachtet. Auch sie können exakt berechnet werden, aber man gelangt nicht zu einem expliziten Ausdruck durch ein gebräuchliches Polynom. Abschließend wird am einfachen Beispiel eines optischen Überganges demonstriert, wie die Integrale anzuwenden sind und wie sie durch einfachere Funktionen approximiert werden können.
Der Unterschied der Protonenresonanzspektren von Cyclopentadienylmetallverbindungen mit Doppelkegel (Sandwich)-Struktur und lokalisierter Metall-Kohlenstoffbindung
Authors: Strohmeier Walter , Lemmon Richard M.
Published: March 2015

Mit Hilfe der kernmagnetischen Resonanzmethode wurden die Protonenresonanzspektren von Cyclopentadienylmetallverbindungen, welche Doppelkegel(Sandwich)-Struktur und lokalisierte Metall-Kohlenstoffbindungen haben, aufgenommen.

Untersucht wurden die Verbindungen: Ferrocen, 1-1′-Dimethylferrocen, Cyclopentadienylmangantricarbonyl, Methylcyclopentadienylmangantricarbonyl, Dicyclopentadienylquecksilber und Cyclopentadienyltrimethylsilicium.

Die chemical shift δ der Ringprotonen variiert von δCH = —1,4 ppm in Dimethylferrocen bis zu δCH=+1,3 ppm in Cyclopentadienyltrimethylsilicium. Die bisherigen Untersuchungen führen zu dem Schluß, daß mit zunehmendem aromatischem Charakter des Cyclopentadienringes die chemical shift nach negativeren Werten verschoben wird, während die Verbindungen mit positiveren Werten der chemical shift δCH eine höhere Reaktivität gegen Maleinsäureanhydrid besitzen. Dicyclopentadienylquecksilber besitzt nur eine einzige scharfe Protonenresonanzlinie bei δCH = +0,7 ppm, so daß es fraglich erscheint, ob diese Substanz eine, im strengen Sinne, lokalisierte Metall-Kohlenstoffbindung besitzt. Für Cyclopentadienyltrimethylsilicium wurden jedoch 2 Resonanzlinien mit dem Intensitätsverhältnis 1 : 4 für die Ringprotonen gefunden, so daß für diese Verbindung eine lokalisierte Metall-Kohlenstoffbindung sichergestellt ist.

Eine Analyse von Gemischen der untersuchten Verbindungen mit Hilfe der kernmagnetischen Protonenresonanzmethode ist möglich.
Calculation of the Ion Optical Properties of Inhomogeneous Magnetic Sector Fields, including the Second Order Aberrations in the Median Plane
Authors: Tasman H. A. , Boerboom A. J. H.
Published: March 2015

Investigation is made of the ion optical properties of inhomogeneous magnetic sector fields. In first order approximation the field is assumed to vary proportional to r—n (0 ≦ n < 1); the term in the magnetic field expansion which determines the second order aberrations is chosen independent of n, which makes the elimination possible of e. g. the second order angular aberration. From the EULER— LAGRANGE equations the second order approximation of the ion trajectories in the median plane and the first order approximation outside the median plane are derived for the case of normal incidence and exit of the central path in the sector field. An equation is presented giving the shape of the pole faces required to produce the desired field. The influence of stray fields is neglected. The object ana image distances are derived, as well as the mass dispersion, the angular, lateral and axial magnification, the resolving power, and the inclination of the plane of focus of the mass spectrum. The maximum transmitted angle in the z-direction is calculated. The resolving power proves to be proportional to (1—n) -1 whereas the length of the central path is proportional to (1—n) -½. An actual example is given of a 180° sector field with n=0.91, where the mass resolving power is increased by a factor 11 as compared with a homogeneous sector field of the same radius and slit widths.
Aufbau und Erprobung eines doppelfokussierenden stigmatisch abbildenden Massenspektrographen
Authors: Sauermann G. , Ewald H.
Published: March 2015

Es wurde ein doppelfokussierender Massenspektrograph gebaut, der an Stelle des üblichen Zylinderkondensators mit einem Toroidkondensator ausgerüstet ist, um zusätzlich zur Doppelfokussierung in radialer Richtung stigmatische Abbildung der Spaltpunkte in die Punkte der Massenlinien zu erhalten. Die Korrektur des zum Quadrat des axialen Öffnungswinkels az proportionalen radialen Bildfehlers /33 wurde durch eine zusätzliche Zylinderkrümmung der Austrittsstirnfläche des Toroidkondensators erreicht. Es konnten damit reproduzierbar scharfe und sehr intensive Massenlinien erhalten werden. Das erreichte Auflösungsvermögen betrug bei einem Ablenkradius von ae = 120 mm im elektrischen Feld etwa 25 000. Infolge der Verkürzung der Massenlinien durch die stigmatische Abbildung betragen die Belichtungszeiten für die intensivsten Linien der Spektren jetzt weniger als 0,1 sec.
Anwendung der nichtlinearen Elastizitätstheorie auf Fehlstellen in Kristallen
Authors: Seeger Alfred , Mann Erich
Published: March 2015

Vom Kontinuumsstandpunkt aus betrachtet können Fehlstellen in Kristallen als Eigenspannungszustände mit Singularitäten (in manchen Fällen auch als Eigenspannungen in mehrfach zusammenhängenden Körpern) beschrieben werden. Die vorliegende Arbeit befaßt sich mit der systematischen Anwendung der nichtlinearen Elastizitätstheorie auf derartige Probleme. Man erreicht dadurch eine gegenüber der üblicherweise verwendeten linearen Theorie verbesserte Beschreibung der Verhältnisse in der unmittelbaren Umgebung der Fehlstellen, in der sehr große Verzerrungen auftreten können. Außerdem lassen sich mit der nichtlinearen Theorie einige in Abschnitt 1 aufgeführte Effekte beschreiben, die von der linearen Theorie prinzipiell nicht wiedergegeben werden können. In Abschnitt 2 wird kurz der Formalismus der sog. Elastizitätstheorie 2. Ordnung (die im Hookeschen Gesetz die Quadrate der Ableitungen der Verschiebungen berücksichtigt) und die experimentelle Bestimmung der hier auftretenden elastischen Konstanten höherer Ordnung besprochen. Abschnitt 3 behandelt ein praktisch wichtiges Sonderproblem, nämlich die Bestimmung der Dilatation, die für die Kleinwinkelstreuung von RÖNTGEN-Strahlen und Neutronen sowie für die Streuung der Leitungselektronen durch Fehlstellen wichtig ist. Wie in den beiden folgenden Abschnitten wird dabei als Rechenmethode die von der linearen Lösung ausgehende Störungsrechnung benützt. Abschnitt 4 gibt die ausführliche und vollständige Lösung für das Verschiebungsfeld einer Schraubenversetzung in einem isotropen Medium. Als letztes, knapper dargestelltes Beispiel wird in Abschnitt 5 als Modell für ein auf einem Zwischengitterplatz eingebautes Atom eine in eine Kugelschale eingezwängte Kugel gleicher elastischer Konstanten behandelt. Bei beiden Problemen wird gefunden, daß eine von ZENER angegebene allgemeine Formel für die Volumänderung infolge von Eigenspannungen in homogenen Medien zutrifft.
Zur Theorie der inneren Feldemission
Authors: Kamphusmann Josef
Published: March 2015

Bei der quantenmechanischen Behandlung der inneren Feldemission stört der Potentialanteil e

des elektrischen Feldes

die Periodizität der SCHRÖDINGER-Gleichung. Deswegen muß man, um sie durch eine Entwicklung nach HOUSTONschen Funktionen lösen zu können, ein unendliches Grundgebiet wählen. In der vorliegenden Arbeit wird gezeigt, wie man diese Bedingung vermeiden kann. Nimmt man nämlich statt der HOUSTONschen Funktionen Wellenpakete aus BLOCHschen Funktionen zu einem endlichen Grundgebiet, die sich als Ganzes nach der klassischen Beschleunigungsgleichung für den Impuls durch den Wellenzahlraum bewegen, so ist es möglich, hiermit den nichtperiodischen Potentialanteil e

zu eliminieren. Es werden Determinantenwellenfunktionen für das Vielelektronenproblem angesetzt. Dabei ergibt sich, daß in dieser Näherung die innere Feldemission ein Einelektronenvorgang ist. Geht man in den Ergebnissen wieder zu einem unendlichen Grundgebiet über, so erhält man genau die HOUSTONsche Theorie.
Trithiadiazyl-hexafluorarsenate S3N2X+AsF6
- / Trithiadiazyl-hexafluoroarsenates S3N2X+AsF6
-
Authors: Padma D. K. , Mews R.
Published: March 2015

The preparation of trithiadiazyl-hexafluoroarsenates by three different methods is reported: (a) reaction of S3N2Cl2 (3) with AgAsF6 (to give S3N2Cl+ ASF6
-), (b) halogen or radical addition to S3N2
+ ASF6
- to give S3N2Br+AsF6
- (5) or S3N2ON(CF3)2 + ASF6
- (6), and (c) cycloaddition of NSF to the NS2
+ -cation to give S3N2F+AsF6
- (9).
Organoborierung von Alkinylstannanen, XX [1] Oligomerisation von 1-Propinyltrimethylstannan / Organoboration of Alkynylstannanes, XX [1] Oligomerisation of 1-Propynyltrimethylstannane
Authors: Bihlmayer Christoph , Kerschl Susanna , Wrackmeyer Bernd , Bihlmayer Christoph , Kerschl Susanna , Wrackmeyer Bernd
Published: March 2015

1-Propynylstannane (1) reacts with B-ethyl-9-borabicyclo[3.3.1]nonane (10) (ratio 2:1) to giva a new butadiene derivative (11). Attempts to oligomerize 1 by organoboration with trimethyl-borane (13) (ratio 2:1) lead to a hexatriene derivative (14). A larger excess of 1 (5:1) gives a mixture of higher oligomers, analogous to 14. The proposed structures of the new compounds 11, 14 are supported by 11B, 13C and 119Sn NMR and mass spectra.