bluuebunny/crossref_metadata_2025 huggingface dataset:
Egophony: is this classic semeiological sign still helpful?
Authors: Viviani Domenico , Gasbarrini Giovanni
Published: April 2013

BACKGROUND Egophony, also known as “E to A change”, is a classical, clinical sign detected by chest auscultation, consisting into a change in timbre, but not pitch or volume, produced by solid interposed between the resonator and the stethoscope head. Egophony was first described in 1916 by R.T.H. Laënnec, but today it is almost unknown. Yet it is a powerful tool to detect pleural effusion as well as other pathological conditions associated with lung compression or consolidation, such as hemothorax or atelectasis of the lung. AIM OF THE STUDY The aim of this paper is to remember the value of this frequently neglected clinical sign and to stress the importance of physical examination, that should always precede – and could often replace – instrumental tests, which are quite expensive and sometimes unnecessary.
Long-term care in orthotopic liver transplantation
Authors: Morelli Maria C. , Pinna Antonio D.
Published: April 2013

Orthotopic liver transplantation is the treatment of choice for selected patients with end-stage liver disease or acute liver failure. Given the excellent long-term survival associated with this procedure, increasing emphasis is being placed on the recognition and prevention of post-transplant complications, detection of recurrent liver disease, and effective management of immunosuppressive drug therapy, which involves regular monitoring of blood levels and the identification of adverse effects and drug interactions. In this context, close interaction between the transplant surgeon, the hepatologist, and the family physician is of great value. The purpose of the present article is to review the multidisciplinary, long-term care of liver transplant recipients, the detection and management of the most common post-transplant complications, and the effects of immunosuppression. The article is based on a PubMed search for articles (original research, reviews, meta-analyses) published between 1995 and 2010. The search terms used were ‘‘liver transplantation’’ AND any of the following: cardiovascular complications, long-term complications, malignancy, post-transplant care.
Prasugrel
Authors: Airoldi Gianluca , Campanini Mauro
Published: April 2013

Antiplatelet drugs are the cornerstone of treatment for patiens with Acute Coronary Syndromes (ACS) undergoing percutaneous coronary intervention. Clopidogrel and aspirin improve longterm vascular clinical outcomes in these patients and have become a standard of care. However, many patients still experience ischemic/thrombotic events due to potential insufficient platelet inhibition. Prasugrel is a novel third-generation oral thienopyridine analog with a structure similar to that of clopidogrel and ticlopidine. Like the other thienopyridines, prasugrel is a pro-drug requiring hepatic metabolism to its active form to inhibit platelet aggregation induced by Adenosine Diphosphate (ADP) by irreversibly binding to the ADP purinergic receptor (P2Y12) on the platelet surface. Laboratory results with prasugrel support more potent antiplatelet effects, a lower interpatient variability in antiplatelet response, and a reduced time to onset of antiplatelet activity compared with clopidogrel, even when clopidogrel is administered at doses higher than the currently approved 300-mg loading dose and 75-mg/day maintenance dose. These differences may have mainly a pharmacokinetic basis.While the active metabolites of prasugrel and clopidogrel show similar levels of platelet inhibitioninvitro, theamount of eachactivemetabolite generatedinvivomaybequite different, expecially in some substet of patients (e.g., the so called ‘‘CYP2C9 poor metabolizers’’). However, it is not yet clear whether these pharmacologic improvements can translate to clinical benefits. The results of the large TRITON-TIMI 38 trial, which compared prasugrel and clopidogrel in patients with acute coronary syndrome who were scheduled to receive coronary stents, demonstrated a significant reduction in ischemic events with prasugrel, although this was associated with a greater risk of bleeding. More studies with prasugrel should determine its optimal dosage regimen to minimize bleeding risks and evaluate its outcomes in ACS in varius subset of patiens. The exact role of prasugrel in the management of coronary heart disease remains to be defined.
Emergence of rabies in the Gauteng Province, South Africa: 2010–2011
Authors: Sabeta Claude T. , Weyer Jacqueline , Geertsma Peter , Mohale Debra , Miyen Jacobeth , Blumberg Lucille H. , Leman Patricia A. , Phahladira Baby , Shumba Wonderful , Walters Johan , Paweska Janusz T.
Published: April 2013

Canine rabies is enzootic throughout Sub-Saharan Africa, including the Republic of South Africa. Historically, in South Africa the coastal provinces of KwaZulu-Natal and Eastern Cape were most affected. Alarmingly, outbreaks of canine rabies have been increasingly reported in the past decade from sites where it has previously been under control. From January 2010 to December 2011, 53 animal rabies cases were confirmed; these were mostly in domestic dogs from southern Johannesburg, which was previously considered to be rabies free. In addition, one case was confirmed in a 26-month old girl who had been scratched by a pet puppy during this period. The introduction of rabies into Gauteng Province was investigated through genetic analysis of rabies positive samples confirmed during the outbreak period. In addition, the nucleotide sequences of incidental cases reported in the province for the past ten years were also included in the analysis. It was found that the recent canine rabies outbreak in the Gauteng Province came from the introduction of the rabies virus from KwaZulu-Natal, with subsequent local spread in the susceptible domestic dog population of southern Johannesburg. The vulnerability of the province was also highlighted through multiple, dead-end introductions in the past ten years. This is the first report of a rabies outbreak in the greater Johannesburg area with evidence of local transmission in the domestic dog population.
Natural Convection in a Concentric Annulus: A Lattice Boltzmann Method Study with Boundary Condition-Enforced Immersed Boundary Method
Authors: Hu Yang , Niu Xiao-Dong , Shu Shi , Yuan Haizhuan , Li Mingjun
Published: April 2013

In this paper, a boundary condition-enforced IBM is introduced into the LBM in order to satisfy the non-slip and temperature boundary conditions, and natural convections in a concentric isothermal annulus between a square outer cylinder and a circular inner cylinder are simulated. The obtained results show that the boundary condition-enforced method gives a better solution for the flow field and the complicated physics of the natural convections in the selected case is correctly captured. The calculated average Nusselt numbers agree well with the previous studies.
The Sistah Powah Structured Writing Intervention: A Feasibility Study for Aging, Low-Income, HIV-Positive Black Women
Authors: DeMarco Rosanna F. , Chan Keith
Published: April 2013

Purpose.

The purpose of this study was to test the feasibility and assess outcomes of health care adherence based on whether participants engage in particular risky behaviors relevant to general health or living with human immunodeficiency virus (HIV) infection and the frequency of these adherent behaviors. Health adherent behaviors include both self-advocacy and decreased stigma as underlying key components.

Design.

A randomized control trial comparing peer-led attention control support and intervention groups.

Setting.

Community-based women's drop-in center in an urban, black neighborhood of Boston, Massachusetts.

Subjects.

Aging, low-income, black women living with HIV infection.

Intervention.

Peer-led, small-group, structured writing using film clips from Women's Voices Women's Lives as a writing prompt.

Measures.

Demographic and outcome data that included adherence, self-advocacy, and stigma; collected at baseline, 6 weeks, and 6 months.

Analysis.

Repeated-measures analysis of variance scores were examined between groups and waves. Paired-sample t-tests were used to examine mean differences across time.

Results.

Sample included 110 women (intervention, n = 56; comparison, n = 54). Retention was 85.5%. Repeated-measures analysis indicated intervention group condom use (n = 69, F = 8.02, df = 1, p < .01) and safe sex (n = 71, F = 13.02, df = 1, p < .01) was higher than that of comparison group. A time effect was also found in the Silencing the Self Scale (n = 91, Pillai's trace = 7.21, df = 2, p < .01).

Conclusion.

This study demonstrates the feasibility of a tailored, peer-led, and culturally relevant interventions and tentative efficacy in populations affected by health disparities. Key limitations include no comparison intervention format with women who can't write and the need to test generalizability.
Lifestyle Behavior Change and Repeat Health Risk Appraisal Participation: A Structural Equation Modeling Approach
Authors: Simpson Vicki L. , Hyner Gerald C. , Anderson James G.
Published: April 2013

Purpose.

Health risk appraisals (HRAs) have been used to address multiple health concerns and lifestyle behaviors. We explore the longitudinal relationship between emotional health, stage of change for five lifestyle behaviors, and lifestyle risks using HRA-generated data.

Design.

Secondary analysis of 3 years of HRA data.

Setting.

A large health care management services provider.

Subjects.

A total of 7535 adults employed across three companies who completed consecutive HRAs over a 3-year period.

Measures.

Self-report items concerning participant health, lifestyle behaviors, disease risk factors, job/life satisfaction, safety, and biometrics.

Analysis.

Structural equation modeling tested a hypothesized longitudinal, fully cross-lagged panel design.

Results.

Results indicated that greater numbers of physical and behavioral risks classified as high risk were associated with greater intention to change or an actual change in lifestyle behavior in the following year. In addition, poorer emotional health was associated with a higher number of risks.

Conclusion.

Data from repeat participation in HRAs can be useful in studying multiple risk behaviors and related health measures, supporting the design and evaluation of effective, individualized, and responsive health promotion activities for working adults.
Kadhis Courts in Kenya’s Constitutional Review (1998–2010): A Changing Approach to Politics and State Among Kenyan Muslim Leaders
Authors: Tayob Abdulkader
Published: April 2013

Debate over Kadhis courts in the constitutional review process (1998–2010) in Kenya antagonized relations between Muslims and Christians. Generally, Muslims found themselves on the defensive as some Christian groups mounted a sustained campaign against the place of Kadhis courts in the constitution. This paper presents Muslim responses to this public debate in the larger framework of Muslims in the nation-state. Since the 1990s, the Kenyan state was engaged in a search for a new politics. This paper turns to this question, and finds that beneath the rhetoric about Kadhis courts, Muslim responses were focused on politics. They were placing the Kadhis court debate within the larger question of how Muslims relate to the nation-state of Kenya.
A Place at the Table: The Political Integration of Muslims in Kenya, 1963–2007
Authors: Bakari Mohamed
Published: April 2013

Kenyan Muslims are well integrated within the Kenyan political system. This process of political integration gained momentum when President Daniel Arap Moi regained power after the aborted military coup attempt by the Kenya Air Force in August 1982. His increasingly authoritarian rule faced a challenge from the younger generation of politicians who began to challenge his legitimacy because of the loss of basic democratic rights through mass demonstrations and civil disobedience. A new generation of Muslim politicians and activists joined the fray. This new Muslim leadership was the product of social transformations that were ushered in by new educational opportunities that presented themselves immediately after Kenya gained independence. Muslims were able to be integrated gradually within the political system through social mobility and pragmatic policies of Jomo Kenyatta and later through the politics of cronyism and co-option under Moi. With the widening of political space and the new politics of inclusion, Muslims have now been completely integrated within Kenyan society.
AUTOMATIC CROWD ANALYSIS FROM VERY HIGH RESOLUTION SATELLITE IMAGES
Authors: Sirmacek B. , Reinartz P.
Published: April 2013

Abstract. Recently automatic detection of people crowds from images became a very important research field, since it can provide crucial information especially for police departments and crisis management teams. Due to the importance of the topic, many researchers tried to solve this problem using street cameras. However, these cameras cannot be used to monitor very large outdoor public events. In order to bring a solution to the problem, herein we propose a novel approach to detect crowds automatically from remotely sensed images, and especially from very high resolution satellite images. To do so, we use a local feature based probabilistic framework. We extract local features from color components of the input image. In order to eliminate redundant local features coming from other objects in given scene, we apply a feature selection method. For feature selection purposes, we benefit from three different type of information; digital elevation model (DEM) of the region which is automatically generated using stereo satellite images, possible street segment which is obtained by segmentation, and shadow information. After eliminating redundant local features, remaining features are used to detect individual persons. Those local feature coordinates are also assumed as observations of the probability density function (pdf) of the crowds to be estimated. Using an adaptive kernel density estimation method, we estimate the corresponding pdf which gives us information about dense crowd and people locations. We test our algorithm usingWorldview-2 satellite images over Cairo and Munich cities. Besides, we also provide test results on airborne images for comparison of the detection accuracy. Our experimental results indicate the possible usage of the proposed approach in real-life mass events.
MULTISCALE HAAR TRANSFORM FOR BLUR ESTIMATION FROM A SET OF IMAGES
Authors: Lelégard L. , Vallet B. , Brédif M.
Published: April 2013

Abstract. This paper proposes a method to estimate the local sharpness of an optical system through the wavelet-based analysis of a large set of images it acquired. Assuming a space-invariant distribution of image features, such as in the aerial photography context, the proposed approach produces a sharpness map of the imaging device over 16 × 16 pixels blocks that enables, for instance, the detection of optical defects and the qualification of the mosaicking of multiple sensor images into a larger composite image. The proposed analysis is based on accumulating of the edge maps corresponding to the first levels of the Haar Transform of each image of the dataset, following the intuition that statistically, each pixel will see the same image structures. We propose a calibration method to transform these accumulated edge maps into a sharpness map by approximating the local PSF (Point Spread Function) with a Gaussian blur.
Engineering geologic assessment of the slope movements and liquefaction failures of the 23 October 2011 Van earthquake (Mw= 7.2)
Authors: Karakaş A. , Coruk Ö. , Doğan B.
Published: April 2013

Abstract. On 23 October 2011, a Mw = 7.2 earthquake occurred in the Van Province in eastern Turkey, killing 604 people. The earthquake was triggered by a thrust fault due to a compression stress in the region, and caused extensive damage over a large area. Many structures in the earthquake region collapsed, and the damage spread from the city of Van to the town of Erciş, in a distance of 60 km. The earthquake generated several slope movements and liquefaction failures in the region, and this study evaluates these processes from the perspective of engineering geology, and presents field and laboratory results related to these processes. Attenuation relationships were used for estimation of peak ground accelerations (PGAs), and an empirical liquefaction evaluation method employing ground accelerations was used to define threshold accelerations initiating the liquefaction. The results demonstrate that landslides were widespread and more frequently observed in the field in comparison with earthflows and rockfalls. Flow-type liquefaction and lateral spreading was found to be widespread and more common than the liquefaction-related settlement. The minimum threshold acceleration value for the initiation of soil liquefaction was calculated to be 188.87 cm s−2 (~0.19 g) in the earthquake region. Laboratory results indicated that the soil liquefaction was closely associated with grain size. The slope instabilities, liquefaction and associated ground failures occurred mainly in rural areas, and their impact on structures was quite low as compared to the human loss and structural damage by the earthquake.
Modeling of the near-field distribution of pollutants coming from a coastal outfall
Authors: Lyubimova T. P. , Roux B. , Luo S. , Parshakova Y. N. , Shumilova N. S.
Published: April 2013

Abstract. The present study concerns the 3-D distribution of pollutants emitted from a coastal outfall in the presence of strong sea currents. The problem is solved using the nonlinear Reynolds-averaged Navier–Stokes equations in the framework of the k-ε model. The constants of the logarithmic law for the vertical velocity profile in the bottom boundary layer are obtained by processing experimental data from acoustic Doppler current profilers (ADCPs). The near-field distribution of pollutants at different distances from the diffuser is obtained in terms of the ambient flow velocity (steady or with tidal effect) and outfall discharge characteristics. It is shown that even in the case where the effluent density is substantially lower than the ambient sea water density the plume can impact the seabed, creating a risk of pollution of removable bottom sediments.
Building Leadership Capacity
Authors: Mukoza Stella Kyobula , Goodman Suki
Published: April 2013

Universities worldwide are becoming increasingly interested in the importance of emerging co-curricula that focus on developing graduate attributes beyond specific academic disciplines. This is being influenced by industry demands for graduates with behavioural and cognitive skills aligned to the work they will do in their early careers. This paper presents findings of a formative evaluation of the Emerging Student Leaders Programme (ESLP) implemented by the University of Cape Town (UCT) in South Africa. The authors adopted a theory and implementation evaluation design and their findings show that the programme conforms to established best practice and, given the pressure on universities to offer specialized training, may serve as a model for other higher education institutions in South Africa and elsewhere.
Interaction Behaviours Among Special Solitons in the (2+1)-Dimensional Modified Dispersive Water-Wave System
Authors: Zhang Wen-Ting , Chen Wei-Lu , Zhang Li-Pu , Dai Chao-Qing
Published: April 2013

A modified mapping method is used to obtain variable separation solutions with two arbitrary functions of the (2+1)-dimensional modified dispersive water-wave system. Based on the variable separation solution and by selecting appropriate functions, we discuss interaction behaviours among special anti-solitons constructed by multi-valued functions. The analysis results exhibit that the interaction behaviours among special anti-dromion, dromion-like anti-peakon, and dromion-like anti-semifoldon are all non-completely elastic and phase shifts exist, while the interaction behaviour among dromionlike anti-semifoldons is completely elastic and without phase shifts.
Authors: Ogungbamila Bolanle
Published: April 2013

Studies on occupational burnout among health workers, especially in Nigeria have been at best isolated. No adequate inter-occupational comparative study on burnout among health workers, police personnel, and teachers has been conducted. This study, therefore, investigated the extent to which health workers were different from police personnel, and teachers in the manifestations of emotional exhaustion, depersonalization, reduced personal accomplishment, and overall occupational burnout. Participants were 455 employees (203 males; 252 females) sampled from 3 service occupations (police = 139; health = 159; teaching = 157), whose ages averaged 35.94 years (SD = 7.93). Health workers reported higher levels of emotional exhaustion, depersonalization, and overall occupational burnout than either police personnel or teachers. Although health workers reported a higher level of reduced personal accomplishment than police personnel, results indicated that teachers felt as underachieving as health workers. The findings were discussed in terms of the perceived imbalance in the job demands-rewards ratio in the job situations.
Europeana: Digital Access to Europe's Cultural Heritage
Authors: Purday Jonathan
Published: April 2013

Europeana is a web-based portal that enables people to explore the digital resources of Europe's museums, libraries, archives and audio-visual collections. It promotes discovery and networking opportunities in a multilingual space where users can engage, share in and be inspired by the rich diversity of Europe's cultural and scientific heritage. The environment in which Europeana operates is volatile, and influenced by unpredictable technological, political and financial forces. While the volatility of these forces can act as a threat, right now they also highlight the potential of Europeana as a force for cross-border integration, a platform for digital innovation and a vehicle for growth. This paper provides an overview of Europeana's success stories over the past year, which has been one of substantial change, fresh initiatives and significant innovation, as well as some of the discussions surrounding the technical challenges of heritage digitization (e.g. copyright, licensing, content sourcing, data models) and the project's plans for distribution and engagement in the forthcoming years.
Algorithm for Generating Train Calendar Texts
Authors: Greiner Karel
Published: April 2013

The article describes a possibility of generating train calendar text for the needs of compiling the annual timetable in the conditions of the Czech Republic. Based on the analysis of the types of texts of calendars that appear in various print outputs, a heuristic algorithm was designed to generate a text from a set of calendar days. The algorithm is a part of an application that also provides a tool to define the text of the calendar by using a mask of sub-periods and calendars to be displayed in them. The algorithm was tested on real data of the timetable. In most cases, the algorithm shows the same or better results than the previously used tools. In several cases, however, a better result can be obtained by the user. The described algorithm to generate the text of the calendar is a part of a program that is used for compiling the timetable for trains in the Czech Republic.
Utilization of Flexible Airspace Structure in Flight Efficiency Optimization
Authors: Mihetec Tomislav , Steiner Sanja , Odić Denis
Published: April 2013

With increasing air traffic demand in the Pan-European airspace there is a need for optimizing the use of the airspace structure (civilian and military) in a manner that would satisfy the requirements of civil and military users. In the area of Europe with the highest levels of air traffic (Core area) 32% of the volume of airspace above FL 195 is shared by both civil and military users. Until the introduction of the concept of flexible use of airspace, flexible airspace structures were 24 hours per day unavailable for commercial air transport. Flexible use of airspace concept provides a substantial level of dynamic airspace management by the usage of conditional routes. This paper analyses underutilization of resources, flexible airspace structures in the Pan-European airspace, especially in the south-eastern part of the traffic flows (East South Axis), reducing the efficiency of flight operations, as result of delegating the flexible structures to military users. Based on previous analysis, utilization model for flexible use of airspace is developed (scenarios) with defined airspace structure. The model is based on the temporal, vertical, and modular airspace sectorisation parameters in order to optimize flight efficiency. The presented model brings significant improvement in flight efficiency (in terms of reduced flight distance) for air carriers that planned to fly through the selected flexible airspace structure (LI_RST-49).
Isolation of volatiles from Nigella sativa seeds using microwave‐assisted extraction: effect of whole extracts on canine and murine CYP1A
Authors: Liu Xue , Park Jong‐Hyouk , Abd El‐Aty A. M. , Assayed M. E. , Shimoda Minoru , Shim Jae‐Han
Published: April 2013

The volatile components of Nigella sativa seeds were isolated using microwave‐assisted extraction (MAE) and identified using gas chromatography. Further investigations were carried out to demonstrate the effects of whole extracts on canine (dog) and murine (rat) cytochrome P450 1A (CYP1A). The optimal extraction conditions of MAE were as follows: 25 mL of water, medium level of microwave oven power and 10 min of extraction time. A total of 32 compounds were identified under the conditions using GC‐FID and GC‐MS. Thymoquinone (38.23%), p‐cymene (28.61%), 4‐isopropyl‐9‐methoxy‐1‐methyl‐1‐cyclohexene (5.74%), longifolene (5.33%), α‐thujene (3.88) and carvacol (2.31%) were the main compounds emitted from N. sativa seeds. Various extracts including pure compounds, essential oil, nonpolar partition, relatively high‐polar/nonpolar partition, and polar partition extracts effectively inhibited the reaction of ethoxyresorufin O‐de‐ethylation, which is specified for CYP1A activity both in dog and rat. This in vitro data should be heeded as a signal of possible in vivo interactions. The use of human liver preparations would considerably strengthen the practical impact of the data generated from this study. Copyright © 2013 John Wiley & Sons, Ltd.
Collecting Informed Consent with Juvenile Justice Populations: Issues and Implications for Research
Authors: Wolbransky Melinda , Goldstein Naomi E. S. , Giallella Christy , Heilbrun Kirk
Published: April 2013

Researchers must provide participants with opportunities to make informed decisions about whether to participate in research studies. Investigators conducting research with youth in the juvenile justice system face unique ethical, legal, and practical challenges to obtaining informed consent. Juvenile justice researchers must navigate multiple legal and ethical standards for collecting informed consent, take into account youths’ dual vulnerabilities as children and prisoners, and overcome practical limitations to obtaining parental/guardian permission. Given the challenges and complexity of obtaining standard informed consent of youth in juvenile justice facilities, this paper provides suggestions for overcoming obstacles to recruiting these youth for research participation. It offers guidance for fostering the enrollment of juvenile justice youth in research studies using procedures that comply with ethical and legal standards for research with this dually vulnerable population. Copyright © 2013 John Wiley & Sons, Ltd.
Analysis of Permeation and Filtration Behavior of Ceramic Membranes under Hydrothermal Conditions
Authors: Felix Alexander , Herdegen Volker , Haseneder Roland , Härtel Georg , Repke Jens‐Uwe
Published: April 2013

Wasser unter erhöhten Temperaturen und Drücken stellt aufgrund seiner physiologischen Unbedenklichkeit sowie vorteilhaften physikalisch‐chemischen Eigenschaften eine interessante Alternative gegenüber einer Vielzahl von organischen und umweltgefährdenden Lösungs‐ und Reaktionsmitteln dar. Um derartigen Verfahren künftig größere Anwendungschancen zu eröffnen, wurden keramische Membranen zur Stofftrennung unter hydrothermalen Druck‐ und Temperaturbedingungen untersucht. Dies beinhaltet den Aufbau einer Permeations‐ und Filtrationsanlage, Parameterstudien zum Transportverhalten des reinen Wassers sowie Untersuchungen zum Trennverhalten der Membranen gegenüber gelösten organischen Modellsubstanzen.
Simulation of Coalescence in Multiphase Systems Using a Mesh‐Free Simulation Method
Authors: Hirschler Manuel , Keller Franz , Huber Manuel , Säckel Winfried , Nieken Ulrich
Published: April 2013

Die Modellierung der Koaleszenz innerhalb von Blasenkollektiven ist mit gitterbasierten Verfahren aufgrund des adaptiven Vernetzungsaufwands eine Herausforderung. Eine Alternative für Systeme mit stark veränderlichen freien Oberflächen und komplexer Geometrie stellen gitterfreie Simulationsmethoden wie der Smoothed‐particle‐hydrodynamics‐Ansatz (SPH‐Ansatz) dar. In dieser Forschungsarbeit wird die Eignung der SPH‐Methode zur Simulation von Blasenkollektiven untersucht. Dazu wird die Dynamik der Koaleszenz einer Einzelblase mit einer planaren Oberfläche analysiert und die Möglichkeit zur Modellierung von Blasenkollektiven am Beispiel eines Blasenkollektivs mit zwei Blasen verschiedener Größe aufgezeigt.
Characterization of thin‐film a‐Si:H/µc‐Si:H tandem solar cells on glass substrates
Authors: Klossek A. , Krause C. , Arguirov T. , Krause H.‐M. , Seifert W. , Friedrich F. , Calnan S. , Gabriel O. , Stannowski B. , Kittler M.
Published: April 2013

Techniques, such as photoluminescence (PL) and electron‐beam‐induced current (EBIC), have already proven their effectiveness and applicability for solar materials. Although, the methods are standard techniques for multicrystalline Si PV, their application to thin films is challenging and requires special adjustment and a careful selection of the measuring parameters. Here we report on the investigation of thin‐film tandem solar cells consisting of hydrogenated amorphous (a‐Si:H) and microcrystalline silicon (µc‐Si:H) on glass substrates. We observe a homogeneous spatial distribution of the PL signals caused by the dominance of the surface recombination. A typical PL spectrum exhibits sub‐band gap features of a‐Si:H. We relate the sub‐band‐gap spectral features mainly to transitions of carriers trapped in deep states. Observations on partially processed stacks support this supposition. PL is only detectable on the a‐Si:H layer, while EBIC signal is generated mainly in the µc‐Si:H layer. It is found out that the luminescence features of the thin a‐Si:H layer resemble those on bulk a‐Si:H.
Breaking the curse of dimensionality in quadratic discriminant analysis models with a novel variant of a Bayes classifier enhances automated taxa identification of freshwater macroinvertebrates
Authors: Ärje J. , Kärkkäinen S. , Turpeinen T. , Meissner K.
Published: April 2013

Macroinvertebrate samples are commonly used in biomonitoring to study changes on aquatic ecosystems. Traditionally, specimens are identified manually to taxa by human experts being time‐consuming and cost intensive. Using the image data of 35 taxa and 64 features, we propose a novel variant of the quadratic discriminant analysis for breaking the curse of dimensionality in quadratic discriminant analysis models. Our variant, called a random Bayes array (RBA), uses bagging and random feature selection similar to random forest. We explore several variations of RBA. We consider three classification (i.e taxa identification) decisions: majority vote, averaged posterior probabilities, and a novel approach; a score of weighted votes. Besides modifying the voting, we propose to weight features according to their importance instead of eliminating the least important features. We compared the performance of RBA with traditional Bayesian and several other popular classification methods and assessed how the methods behave in relation to each other and the different macroinvertebrate species. Further, we investigate how severely misclassifications affect the performance of different methods when set into a biomonitoring context. We found that the lowest and least severe classification error (i.e. most accurate taxa identification) was achieved with RBA by using averaged posterior probabilities and weighted features. Copyright © 2013 John Wiley & Sons, Ltd.
Dendronized Polymer Architectures for Fuel Cell Membranes
Authors: Nielsen M. M. , Dimitrov I. , Takamuku S. , Jannasch P. , Jankova K. , Hvilsted S.
Published: April 2013

Multi‐step synthetic pathways to low‐ion exchange capacity (IEC) polysulfone (PSU) with sulfonic acid functionalized aliphatic dendrons and sulfonated comb‐type PSU structures are developed and investigated in a comparative study as non‐fluorinated proton exchange membrane (PEM) candidates. In each case the side chains are synthesized and introduced in their sulfonated form onto an azide‐functionalized PSU via click chemistry. Three degrees of substitution of each architecture were prepared in order to evaluate the dependence on number of sulfonated side chains. Solution cast membranes were evaluated as PEMs for use in fuel cells by proton conductivity measurements, and in the case of dendronized architectures: thermal stability. The proposed synthetic strategy facilitates exploration of a non‐fluorous system with various flexible side chains where IEC is tunable by the degree of substitution.
Graphene and Functionalized Graphene Supported Platinum Catalyst for PEMFC
Authors: Ghosh A. , Basu S. , Verma A.
Published: April 2013

The graphene was synthesized by chemical oxidation followed by thermal exfoliation of natural graphite. The functionalized graphene (FG) was prepared by chemical treatment of the synthesized graphene. The as‐synthesized graphene and FG were characterized and used as Pt support materials. The 20 wt.% Pt/G and 20 wt.% Pt/FG catalysts were prepared by precipitation method. The prepared catalysts were characterized for particle size using X‐ray diffraction, surface morphology, electrochemical performance, and stability using cyclic voltammetry. The electrochemical surface area of the FG supported platinum catalyst was found to be more than 45% as compared to the commercial carbon supported platinum catalyst. The stability of the developed catalyst (Pt/G and Pt/FG) was significantly higher than the commercial Pt/C. The membrane electrode assembly was developed using the catalysts and tested in a PEMFC. The maximum power densities of the fuel cell were found to be 314, 426, and 455 mW cm–2 using Pt/C, Pt/G, and Pt/FG, respectively.
Siglec‐h on activated microglia for recognition and engulfment of glioma cells
Authors: Kopatz Jens , Beutner Clara , Welle Kristian , Bodea Liviu G. , Reinhardt Julia , Claude Janine , Linnartz‐Gerlach Bettina , Neumann Harald
Published: April 2013

Sialic‐acid‐binding immunoglobulin‐like lectin‐h (Siglec‐h) is a recently identified mouse‐specific CD33‐related Siglec that signals via DAP12/TYROBP. Expression of Siglec‐h has been observed on plasmacytoid dendritic cells and microglia, but the ligand and the function of Siglec‐h remained elusive. Here, we demonstrate gene transcription and protein expression of Siglec‐h by mouse microglia after interferon‐γ treatment or polarization into a M1‐subtype. Microglial Siglec‐h acted as phagocytosis receptor since targeting of microsphere beads to Siglec‐h triggered their uptake into the microglia. The extracellular domain of Siglec‐h protein bound to mouse glioma lines, but not to astrocytes or other normal mouse cells. Microglial cells stimulated to express Siglec‐h engulfed intact glioma cells without prior induction of apoptosis and slightly reduced glioma cell number in culture. Phagocytosis of glioma cells by activated microglia was dependent on Siglec‐h and its adapter molecule DAP12. Thus, data show that M1‐polarized microglial cells can engulf glioma cells via a DAP12‐mediated Siglec‐h dependent mechanism.
Assessment of tonotopically organised subdivisions in human auditory cortex using volumetric and surface‐based cortical alignments
Authors: Langers Dave R.M.
Published: April 2013

Although orderly representations of sound frequency in the brain play a guiding role in the investigation of auditory processing, a rigorous statistical evaluation of cortical tonotopic maps has so far hardly been attempted. In this report, the group‐level significance of local tonotopic gradients was assessed using mass‐multivariate statistics. The existence of multiple fields on the superior surface of the temporal lobe in both hemispheres was shown. These fields were distinguishable on the basis of tonotopic gradient direction and may likely be identified with the human homologues of the core areas AI and R in primates. Moreover, an objective comparison was made between the usage of volumetric and surface‐based registration methods. Although the surface‐based method resulted in a better registration across subjects of the grey matter segment as a whole, the alignment of functional subdivisions within the cortical sheet did not appear to improve over volumetric methods. This suggests that the variable relationship between the structural and the functional characteristics of auditory cortex is a limiting factor that cannot be overcome by morphology‐based registration techniques alone. Finally, to illustrate how the proposed approach may be used in clinical practice, the method was used to test for focal differences regarding the tonotopic arrangements in healthy controls and tinnitus patients. No significant differences were observed, suggesting that tinnitus does not necessarily require tonotopic reorganisation to occur. Hum Brain Mapp 35:1544–1561, 2014. © 2013 Wiley Periodicals, Inc.
3D interconnected porous biomimetic scaffolds: In vitro cell response
Authors: Panzavolta Silvia , Torricelli Paola , Amadori Sofia , Parrilli Annapaola , Rubini Katia , della Bella Elena , Fini Milena , Bigi Adriana
Published: April 2013

Bone cell response to 3D bioinspired scaffolds was tested on osteoblast culture supernatants and by means of quantitative polymerase chain reaction (qPCR). Foaming and freeze‐drying method was optimized in order to obtain three‐dimensional interconnected porous scaffolds of gelatin at different contents of nanocrystalline hydroxyapatite (HA). Addition of a non toxic crosslinking agent during foaming stabilized the scaffolds, as confirmed by the slow and relatively low gelatin release in phosphate buffer up to 28 days. Micro‐computed tomography reconstructed images showed porous interconnected structures, with interconnected pores displaying average diameter ranging from about 158 to about 71 μm as the inorganic phase content increases from 0 to 50 wt %. The high values of connectivity (>99%), porosity (> 60%), and percentage of pores with a size in the range 100–300 μm (>50%) were maintained up to 30 wt % HA, whereas higher content provoked a reduction of these parameters, as well as of the average pore size, and a significant increase of the compressive modulus and collapse strength up to 8 ± 1 and 0.9 ± 0.2 MPa, respectively. Osteoblast cultured on the scaffolds showed good adhesion, proliferation and differentiation. The presence of HA promoted ALP activity, TGF‐β1, and osteocalcin production, in agreement with the observed upregulation of ALP, OC, Runx2, and TGF‐β1 gene in qPCR analysis, indicating that the composite scaffolds enhanced osteoblast activation and extra‐cellular matrix mineralization processes. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3560–3570, 2013.
A model for partitioning the light absorption coefficient of suspended marine particles into phytoplankton and nonalgal components
Authors: Zheng Guangming , Stramski Dariusz
Published: April 2013

We developed a model for partitioning the spectral absorption coefficient of suspended marine particles, ap(λ), into phytoplankton, aph(λ), and nonalgal, ad(λ), components based on the stacked‐constraints approach. The key aspect of our model is the use of a set of inequality constraints that account for large variability in the aph(λ) and ad(λ) coefficients within the world's oceans. The bounds of inequality constraints were determined from the analysis of a comprehensive set of 505 field determinations of absorption coefficients in various oceanic environments. The feasible solutions of the model are found by simultaneously satisfying all inequality constraints. The optimal solutions represented by the median values of feasible solutions for aph(λ) and ad(λ) generally agree well with field measurements and are superior in terms of error statistics compared with previous partitioning models. For example, on the basis of comparisons of optimal model solutions with field determinations of absorption coefficients, the systematic error calculated as the median ratio of model‐derived to measured values for both aph(443) and ad(443) is within ±1% for our model. The random error represented by the mean absolute percent difference for aph(443) and ad(443) is <5% and <20%, respectively. This study suggests that our model has the potential for successful applications with input data of ap(λ) which can be collected from various oceanographic platforms.
Large shield volcanoes on the Moon
Authors: Spudis Paul D. , McGovern Patrick J. , Kiefer Walter S.
Published: April 2013

The volcanic style of the Moon has long been understood to consist almost exclusively of flood basalts erupted from fissures along with minor pyroclastic activity; large central vent shield volcanoes that characterize basaltic volcanism on the other terrestrial planets appeared to be absent. Small (few kilometers diameter) central vent constructs have long been recognized in the lunar maria and often are found clustered in fields throughout the lunar maria. New global topographic data from the LOLA and LROC instruments on LRO reveal that almost all of these volcanic complexes on the Moon occur on large, regional topographic rises in the lunar maria, tens to hundreds of kilometers in extent and between several hundred to several thousand meters high. We propose that these topographic swells are shield volcanoes and are the lunar equivalents of the large basaltic shields found on the Earth, Venus, and Mars. The newly recognized lunar shields are found peripheral to the large, deeply flooded impact basins Imbrium and Serenitatis, suggesting a genetic relation to those features. Loading of the lithosphere by these basalt‐filled basins may be responsible for inducing a combination of flexural and membrane stress, inducing a pressure distribution on vertically oriented dikes favorable to magma ascent. This condition would occur in a zone annular to the large circular loads produced by the basins, where the shield volcanoes occur.
New insights into the global composition of the lunar surface from high‐energy gamma rays measured by Lunar Prospector
Authors: Peplowski Patrick N. , Lawrence David J.
Published: April 2013

An analysis of the lunar gamma‐ray spectrum as measured by the Lunar Prospector Gamma‐Ray Spectrometer has revealed that 8–8.9 MeV gamma rays contain information about the elemental composition of near‐surface materials. These high‐energy gamma rays are found to be primarily sensitive to the total Fe and Mg content of the surface, although other elements also contribute. This information has been used to identify several regions with unique compositions, including the Hertzsprung and Orientale basins. A method for deriving global Mg abundances from high‐energy gamma‐ray measurements is presented. The physical mechanism for high‐energy gamma‐ray production is proposed to be radiation produced during the decay of galactic cosmic ray produced pions within the lunar surface. Laboratory measurements of pion production cross sections are found to be consistent with the empirically derived relationship between the lunar Fe, Mg, and Ti abundances and the measured high‐energy gamma‐ray count rates.
Exposures of olivine‐rich rocks in the vicinity of Ares Vallis: Implications for Noachian and Hesperian volcanism
Authors: Wilson J. H. , Mustard J. F.
Published: April 2013

The igneous evolution of Mars is well represented in stratigraphic settings that transition across major time stratigraphic boundaries. Here we analyze in detail the morphology and composition, determined through visible–near‐infrared spectroscopy, of igneous volcanic terrains in Ares Vallis, Mars. Upland plateau units with crater‐filling volcanic plains are of Noachian age; smooth units to the west and north of the mouth of Ares Vallis have been mapped as Hesperian in age. The age and origin of the units that comprise the floor of Ares Vallis, connecting the upland plateau units and the smooth units to the west and north of the mouth of Ares Vallis, is less certain due to the small area available for crater counting. The mafic mineral compositions of these units are well resolved with OMEGA (Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activité) and CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) data. The data show that the Noachian volcanic units are distinctly olivine‐rich, while the plains units to the west and the floor of Ares Vallis volcanics show diagnostic absorptions of olivine‐pyroxene, typical of Hesperian volcanics elsewhere on Mars. Based on these findings, we propose there has been a change in the temperature and/or degree of partial melting in the mantle over time for this region of Mars.
Functional nasal morphology of chimaerid fishes
Authors: Howard Lauren E. , Holmes William M. , Ferrando Sara , Maclaine James S. , Kelsh Robert N. , Ramsey Andrew , Abel Richard L. , Cox Jonathan P.L.
Published: April 2013

Holocephalans (chimaeras) are a group of marine fishes comprising three families: the Callorhinchidae (callorhinchid fishes), the Rhinochimaeridae (rhinochimaerid fishes) and the Chimaeridae (chimaerid fishes). We have used X‐ray microcomputed tomography and magnetic resonance imaging to characterise in detail the nasal anatomy of three species of chimaerid fishes:Chimaera monstrosa,C. phantasmaandHydrolagus colliei. We have shown that the nasal chamber of these three species is linked to the external environment by an incurrent channel and to the oral cavity by an excurrent channel via an oral groove. A protrusion of variable morphology is present on the medial wall of the incurrent channel in all three species, but is absent in members of the two other holocephalan families that we inspected. A third nasal channel, the lateral channel, functionally connects the incurrent nostril to the oral cavity, by‐passing the nasal chamber. From anatomical reconstructions, we have proposed a model for the circulation of water, and therefore the transport of odorant, in the chimaerid nasal region. In this model, water could flow through the nasal region via the nasal chamber or the lateral channel. In either case, the direction of flow could be reversed. Circulation through the entire nasal region is likely to be driven primarily by the respiratory pump. We have identified several anatomical features that may segregate, distribute, facilitate and regulate flow in the nasal region and have considered the consequences of flow reversal. The non‐sensory cilia lining the olfactory sensory channels appear to be mucus‐propelling, suggesting that these cilia have a common protective role in cartilaginous fishes (sharks, rays and chimaeras). The nasal region of chimaerid fishes shows at least two adaptations to a benthic lifestyle, and suggests good olfactory sensitivity, with secondary folding enhancing the hypothetical flat sensory surface area by up to 70%. J. Morphol. 274:987–1009, 2013. © 2013 Wiley Periodicals, Inc.