bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanoanalytische Methoden und ihre Anwendungsfelder
Authors: Albers Peter 
Published: February 2011

AbstractDie Funktion feinteiliger Produkte wie Verstärkerfüllstoffe für Autoreifen und die Leistungsfähigkeit technischer Katalysatoren ist durch Morphologie und chemische Zusammensetzung bis in den Subnanometerbereich bestimmt. Diese Eigenschaften zu kontrollieren und zu optimieren, setzt verlässliche nanoanalytische Messdaten voraus.
Eine Chemikalie scheidet die Geister
Authors: Osterath Brigitte 
Published: February 2011

AbstractDie einen sehen Gefahren: Bisphenol A gehöre stark eingeschränkt. Die anderen verweisen auf die wissenschaftlichen Beweise, dass die Substanz in den vorherrschenden Mengen für den Menschen harmlos sei. Diese Ansicht hat die europäische Behörde für Lebensmittelsicherheit Ende September 2010 erneut bestätigt. Trotzdem verbietet die EU‐Kommission ab Juni Bisphenol A in Babyflaschen.
Die Seltenheit der Selten‐Erd‐Exporte
Authors: Wildemann Kathrin 
Published: February 2011

AbstractKein Handy, kein LCD‐Bildschirm, kein Hybridauto kommt ohne Seltene Erden aus. Fast den gesamten Weltbedarf deckt China — aber es schränkt die Exporte immer stärker ein.
Als Chemiker beim Umweltbundesamt
Authors: Pritzsche Marc 
Published: February 2011

AbstractDirekt nach meiner Promotion habe ich beim Umweltbundesamt eine Stelle im Fachgebiet Chemikalien angenommen. Meinen Kollegen an der Universität hatten teilweise nur wenig Verständnis dafür: Warum die Forschung verlassen und in einen vermeintlich trockenen Behördenjob wechseln? Heute, zwei Jahre später, weiß ich: Ich habe mich richtig entschieden.
Systemchemie — interdisziplinär und komplex
Authors: Dieckmann Arne 
Published: February 2011

AbstractMehrere Variablen gleichzeitig und nicht nur isoliert voneinander zu studieren, ist bei komplexen chemischen Reaktionssystemen unabdingbar. Um die erhaltenen Daten zu analysieren, muss ein Chemiker oft auch Programmierer sein.
Probing the growth of β‐FeSi2 nanoparticles for photovoltaic applications: a combined imaging and spectroscopy study using transmission electron microscopy
Authors: Wong A.S.W. , Ho G.W. , Liew S.L. , Chua K.C. , Chi D.Z. 
Published: February 2011

AbstractThe microstructure of β‐FeSi2 nanoparticles grown using magnetron sputtering on Si has been examined using various electron microscopy techniques. FeSi2 nanoparticles as small as ∼4 nm are found embedded in Si after growth using co‐sputtering of FeSi2 and Si, followed by rapid thermal annealing (RTA). The formation of nanoparticles and its variation in density with Fe content is discussed in terms of phase separation. Our study shows that the size and density of the nanoparticles as well as the extent of Fe diffusion into sputtered Si and substrate can be controlled by controlling the Fe content in the co‐sputtered film. Copyright © 2011 John Wiley & Sons, Ltd.
Photoluminescence study of Ge containing crystal defects
Authors: Kittler Martin , Arguirov Tzanimir , Oehme Michael , Yamamoto Yuji , Tillack Bernd , Abrosimov Nikolai V. 
Published: February 2011

AbstractMulti‐crystalline Ge (mc‐Ge) and Ge layers on Si substrate grown by MBE and CVD are studied. The photoluminescence (PL) spectra are analysed by comparison with those obtained for bulk Ge. We present a scheme which explains the temperature dependence of the peak positions of the direct and indirect lines observed in the PL spectra. The complex fine structure of the indirect band, consisting of different sub‐peaks, can be understood in terms of phonon assisted processes. Around 80 K emission of longitudinal acoustic (LA) phonons is the decisive process whereas at room temperature absorption of LA phonons dominates. Moreover, PL spectra measured in material with crystal defects suggest that multi‐phonon absorption is involved in the formation of the indirect sub‐peaks. As compared to mono‐Ge the overall luminescence intensity of MBE and CVD grown Ge layers on Si substrate is strongly reduced. In the CVD grown Ge layers the direct line dominates at room temperature whereas in the MBE grown layers the indirect lines are found to be decisive. A shift of the peak positions for the Ge layers to lower energy (10 meV and more) is caused by tensile strain. In the Ge layers on Si and in mc‐Ge, respectively, at 300 or 80 K several lines are observed, ranging roughly between 0.45 and 0.6 eV, which are originated by crystal defects/dislocations.
Enhanced Field Emission and Improved Supercapacitor Obtained from Plasma‐Modified Bucky Paper
Authors: Roy Soumyendu , Bajpai Reeti , Soin Navneet , Bajpai Preeti , Hazra Kiran S. , Kulshrestha Neha , Roy Susanta Sinha , McLaughlin James A. , Misra D. S. 
Published: February 2011

AbstractThe surface morphology of bucky papers (BPs) made from single‐walled carbon nanotubes (CNTs) is modified by plasma treatment resulting in the formation of vertical microstructures on the surface. The shapes of these structures are either pillarlike or conelike depending on whether the gas used during plasma treatment is Ar or CH4. A complex interplay between different factors, such as the electric field within the plasma sheath, polarization of the CNT, intertubular cohesive forces, and ion bombardment, result in the formation of these structures. The roles played by these factors are quantitatively and qualitatively analyzed. The final material is flexible, substrate‐free, composite‐free, made only of CNTs, and has discrete vertically aligned structures on its surface. It shows enhanced field emission and electrochemical charge‐storage capabilities. The field enhancement factor is increased by 6.8 times, and the turn‐on field drops by 3.5 times from an initial value of 0.35 to 0.1 V μm−1 as a result of the treatment. The increase in Brunauer–Emmett–Teller surface area results in about a fourfold improvement in the specific capacitance of the BP electrodes. Capacitance values before and after the treatments are 75 and 290 F g−1, respectively. It is predicted that this controlled surface modification technique could be put to good use in several applications based on macroscopic CNT films.
Application of wavelength dispersive X‐ray spectroscopy to improve detection limits in X‐ray analysis
Authors: Kavčič M. , Žitnik M. , Bučar K. , Szlachetko J. 
Published: February 2011

AbstractIn this work, a Johansson‐type crystal spectrometer was employed to record the high‐resolution L X‐ray emission spectra of pure Ag, Pd and Cd target in order to determine minimum detection limits (MDL) for trace amounts of Pd and Cd in silver. The X‐ray emission was induced by a 3 MeV proton beam as well as by monochromatic synchrotron radiation with excitation energy tuned just below the Ag L3 edge. As a direct consequence of extremely high spectrometer resolution reaching below the natural line widths of the measured L X‐ray lines, detection limits of a few tens of parts per million were reached in case of proton excitation. These limits were additionally lowered by an order of magnitude using energy‐selective photoexcitation with synchrotron radiation as the signal from the resonant Raman scattering (RRS) was completely separated from the Pd signal. The method presented in this work can be used in general to substantially improve detection limits in case of trace elements with atomic number in the close vicinity of the atomic number of the target matrix element. Copyright © 2011 John Wiley & Sons, Ltd.
Theoretical basis for the experimental determination of the intrinsic resolution of a strip detector
Authors: Samedov Victor V. 
Published: February 2011

AbstractThe principal contribution to the peak broadening is the broadening determined by the intrinsic particles' (iparticles) statistics. Iparticles are particles which are generated in the detector's absorber by incident X‐rays and cause signals at the detector's output. Detectors of this type are superconducting and scintillation detectors with quasiparticles and light photons as iparticles, correspondingly. In this work, the theory of branching cascade processes is applied to the description of signal formation in a detector with a single iparticles absorber and several outputs for soft X‐rays. From this theory, it follows the new method of experimental determination of the Fano factor. It is shown that the covariance between two signals of a strip detector depends on the fundamental combination of the Fano factor and the effective energy of the intrinsic particle creation in the absorber material. Independent determination of the effective energy of the intrinsic particle creation allows determining the value of the Fano factor. The important advantage of the proposed method is its independence from the sensors' electronic gains and noise. Copyright © 2011 John Wiley & Sons, Ltd.
Medical Student Surgery Elective in Rural Haiti: A Novel Approach to Satisfying Clerkship Requirements While Providing Surgical Care to an Underserved Population
Authors: Chin‐Quee Anthony , White Laura , Leeds Ira , MacLeod Jana , Master Viraj A. 
Published: February 2011

AbstractBackgroundThe addition of global health programs to medical school training results in graduates with enhanced clinical skills and increased sensitivity to cost issues. Funding from U.S. medical schools has been unable to meet student demand, and therefore it is often a critical limiting factor to the lack of development of these programs. We describe an alternative approach for global health surgical training for medical students.MethodsEmory University medical students and faculty, in collaboration with Project Medishare for Haiti, planned, raised funds, and executed a successful short‐term surgical camp to supplement available surgical services in rural Haiti. Learning objectives that satisfied Emory University School of Medicine surgery clerkship requirements were crafted, and third‐year students received medical school credit for the trip.ResultsIn the absence of house staff and placed in an under‐resourced, foreign clinical environment, the surgical elective described here succeeded in meeting learning objectives for a typical third‐year surgical clerkship. Objectives were met through a determined effort to ensure that home institution requirements were aligned properly with learning activities while students were abroad and through a close collaboration between medical students, faculty members, and the administration.ConclusionsEmory University’s international surgery elective for medical students demonstrates that opportunities for supervised, independent student‐learning and global health service can be integrated into a traditional surgical clerkship. These opportunities can be organized to meet the requirements and expectations for third‐year surgery clerkships at other medical colleges. This work also identifies how such trips can be planned and executed in a manner that does not burden strained academic budgets with further demands on resources.
Prognostic Role of Carcinoembryonic Antigen is Influenced by Microsatellite Instability Genotype and Stage in Locally Advanced Colorectal Cancers
Authors: Søreide Kjetil , Søreide Jon Arne , Kørner Hartwig 
Published: February 2011

AbstractBackgroundCarcinoembryonic antigen (CEA) is the most frequently used marker for colorectal cancer (CRC). Influence of genetic instability on tumor marker expression is not known. The aim of this study was to investigate microsatellite instability (MSI) of CEA serum levels in locally advanced CRC.MethodsThe observational cohort consisted of stage II–III CRC patients (n = 131) 75 years old or youngerwho underwent surgery with curative intent. CEA serum levels were measured before (preCEA) and immediately after surgery (postCEA). DNA from the extracted tumors was investigated for MSI. Survival was analyzed in univariate and multivariate analyses.ResultsThe median preCEA was 3 U/ml (IQR = 1–3, range = 1–136 U/ml). Stage III cancers with MSI had an elevated preCEA more often than those without MSI (25% vs. 0%; p = 0.026). A preCEA >10 U/ml was significantly associated with elevated postCEA (CEA >1 U/ml; odds ratio [OR] = 5.4, 95% CI = 2.1‐14.2; p < 0.001). Survival wasnot significantly different between those with postCEA <10 U/ml vs. postCEA ≥10 U/ml or when stratified by MSI status. A cutoff of postCEA ≤1 U/ml conferred significantly improved survival compared to higher CEA levels. Stratified for MSI status, this difference was significant for microsatellite stable (MSS) cancers only (p = 0.021). In multivariate analysis, postCEA >1 U/ml (hazard ratio [HR] = 3.5, 95% CI = 1.7–7.3, p = 0.001) and stage III (HR = 6.7, 95% CI = 3.0–14.9; p < 0.001) were predictors of decreased survival.ConclusionsPreoperative CEA levels were significantly higher in stage III cancers with the MSI genotype, and high preoperative CEA was associated with increased postoperative CEA. Absent postoperative CEA in serum conferred improved long‐term survival.
Life‐history and demographic variation in an alpine specialist at the latitudinal extremes of the range
Authors: Wilson Scott , Martin Kathy 
Published: February 2011

AbstractAlpine environments are unique systems to examine variation in life‐history strategies because temperature and seasonality are similar across broad latitudinal gradients. We studied the life‐history strategies, demography and population growth of white‐tailed ptarmigan Lagopus leucura, an alpine specialist, at the latitudinal extremes of the range in the Yukon (YK, studied from 2004 to 2008) and Colorado (CO, 1987–1996). The two populations were separated by 2,400 km of latitude, and the Yukon site was approximately 2,000 m lower in elevation than the Colorado site. Yukon females bred on average 9 days earlier than those in Colorado, but the latter study was conducted 15 years earlier and breeding dates may have advanced over this period. The length of the breeding season was similar between the two populations, and females had comparable probabilities of re‐nesting after failure. The two populations differed in how they allocated effort to the first clutch as Yukon females laid larger clutches (7.1 vs. 5.9 eggs) but smaller eggs (18.8 vs. 20.5 g) than those in Colorado. Demographic rates also differed; nest survival was higher in the Yukon (0.40) than in Colorado (0.24), and the resultant annual fecundity was nearly twice as high in the Yukon (3.92 vs. 1.77 chicks/female). In contrast, annual adult survival was higher in Colorado although the confidence intervals overlapped (females: YK = 0.35, CO = 0.44; males: YK = 0.48, CO = 0.59). Estimates of annual population growth (λ) indicated both populations were declining, especially in Colorado (λYK = 0.83, λCO = 0.66), and thus, dispersal movements are likely key to long‐term persistence in both cases. Our findings suggest that breeding‐season temperature and seasonality affect measures related to timing of reproduction, but not the costs and benefits of clutch and egg size.
UK experience of liver transplantation for erythropoietic protoporphyria
Authors: Dowman Joanna K. , Gunson Briget K. , Mirza Darius F. , Badminton Mike N. , Newsome Philip N. ,   on behalf of the UK Liver Selection and Allocation Working Party
Published: February 2011

AbstractErythropoietic protoporphyria (EPP) is characterised by excess production of free protoporphyrin from the bone marrow, most commonly due to deficiency of the enzyme ferrochelatase. Excess protoporphyrin gives rise to the cutaneous photosensitivity characteristic of the disease, and in a minority of patients leads to end‐stage liver disease necessitating liver transplantation (LT). There is limited information regarding the timing, impact and long‐term outcome of LT in such patients, thus we aimed to identify the indications and outcomes of all transplants performed for EPP in the UK using data from the UK Transplant Registry. Between 1987 and 2009, five patients underwent LT for EPP liver disease. Median follow‐up was 60 months, and there were two deaths at 44 and 95 months from causes unrelated to liver disease. The remaining recipients are alive at 22.4 years, 61 months and 55 months after transplant. A high rate of postoperative biliary stricturing requiring multiple biliary interventions was observed. Recurrent EPP‐liver disease occurred in 4/5 (80%) of patients but graft failure has not been observed. Given the role of biliary obstruction in inducing EPP‐mediated liver damage, we suggest that consideration should be given for construction of a Roux loop at the time of transplant. Thus we demonstrate that although EPP liver transplant recipients have a good long‐term survival, comparable to patients undergoing LT for other indications, biliary complications and disease recurrence are almost universal, and bone marrow transplantation should be considered where possible.
Temperature mediates competitive exclusion and diversity in benthic microalgae under different N:P stoichiometry
Authors: Hillebrand Helmut 
Published: February 2011

AbstractThe dependence of competitive interactions on abiotic conditions is attracting increasing interest in the face of globally rising temperatures and altered biogeochemical cycles of major nutrients. In a microcosm experiment involving a natural inoculum of benthic microalgae, temperature and nutrient supply ratios were manipulated in order to test three main hypotheses: (1) temperature and nutrient supply ratios determine species composition and diversity of the assemblage, (2) the identity of the dominating species depends on nutrient supply and temperature, and (3) higher temperature leads to faster competitive exclusion and thus more rapid decline in species richness. Over a period of 7 weeks, algal biomass reached an equilibrium carrying capacity, with was higher at colder temperatures and intermediate N:P supply ratios (N:P = 16). Initial growth rate increased with temperature and under high P‐supply. Species richness in the stationary phase of the experiment decreased with increasing temperature, reflecting a higher extinction rate in the warmer treatments, which were also characterized by higher dominance of single species. Thus, increasing temperature both altered the identity of the dominating species and accelerated competitive displacement. This experiment thus indicates that warming might influence outcome and temporal dynamics in species interactions, and thereby eventually local diversity.
Plastic changes in head size during juvenile development of the butterfly Pieris napi
Authors: Ohata Masaaki , Furumoto Atsuko , Ohsaki Naota 
Published: February 2011

AbstractAmong herbivorous insects, the ability to change adaptive traits plastically in response to novel host plants is advantageous for coping with sudden environmental shifts. The host plants in our study were two closely related species, viz., Arabis flagellosa (tougher leaves, i.e., they are physically defended) and A. gemmifera (softer leaves that are physiologically defended). We demonstrated that young larvae of the butterfly Pieris napi are able to plastically change head size during development in response to changes in food plant species. When larvae were fed the physically defended A. flagellosa, the head sizes of third instar larvae emerging from eggs originally collected from leaves of both A. flagellosa and A. gemmifera became identically larger. When larvae fed on the physiologically defended A. gemmifera, the head sizes of third instar larvae emerging from eggs originally collected from leaves of both A. flagellosa and A. gemmifera became identically smaller. When leaves of A. flagellosa were presented to fourth instars reared on A. flagellosa, larvae with larger heads consumed more food than those with smaller heads. In contrast, when leaves of the physiologically defended A. gemmifera were presented to fourth instar larvae reared on A. gemmifera, larvae with smaller heads processed more food than those with larger heads. Hence, larvae of P. napi retain the capacity for adaptive plastic responses to novel host plant species.
One‐step collagenase method for zona pellucida removal in unfertilized eggs: easy and gentle method for large‐scale preparation
Authors: Yamatoya Kenji , Ito Chizuru , Araki Motoyuki , Furuse Ryoji , Toshimori Kiyotaka 
Published: February 2011

AbstractPurposeZona pellucida (ZP)‐free eggs are often used for studies such as evaluating the interaction of sperm‐oolemma. To acquire ZP‐free eggs, the most commonly used methods employ acidified Tyrode's solution, enzymatic digestion with a trypsin‐like enzyme, or mechanical methods using micropipettes. However, acidified Tyrode's solution and trypsin‐like enzymes often damage the oolemma, especially when many eggs are treated at once for mass sample analyses. The mechanical method requires skill, and it is time‐consuming to prepare many ZP‐free eggs. Therefore, in this study, to establish an easy, reliable method for preparing ZP‐free eggs, we examined the ZP digestion method originally reported by Zuccotti et al. (J Reprod Fertil 93:515–520, 1991) that uses collagenase.MethodsMouse unfertilized eggs were treated with collagenase and acidified Tyrode's solution to compare the ZP‐free rates, the effect on the oolemma, and the two‐cell development rates of ZP‐free eggs by in vitro fertilization. The effects on the oolemma were gauged by observing the polarity of the transmembrane protein localization of enhanced green fluorescence protein tagged CD9 protein (CD9‐EGFP) and using differential interference contrast microscopy.ResultsCollagenase removed the ZP and the cumulus cells from the cumulus oocyte complex. The collagenase method had no influence on the localization of CD9‐EGFP, resulting in a high two‐cell development rate. Additionally, the collagenase method could exclude low quality eggs with hardened ZP, since collagenase could not digest the hardened ZP.ConclusionsThe one‐step collagenase method is an easy preparation method for large numbers of high‐quality ZP‐free eggs.
ON THE STABILITY OF STATIONARY LINE AND GRIM REAPER IN PLANAR CURVATURE FLOW
Authors: WANG XIAOLIU , WO WEIFENG 
Published: February 2011

AbstractThe asymptotic stability of two types of invariant solutions under a curvature flow in the whole plane is studied. First, by extending the work of others, we prove that the stationary line with nonzero slope will attract the graphical curves which surround it. Then a similar property is obtained for the grim reaper.
A CONTINUITY CHARACTERIZATION OF ASPLUND SPACES
Authors: GILES J. R. 
Published: February 2011

AbstractA Banach space is an Asplund space if every continuous gauge has a point where the subdifferential mapping is Hausdorff weak upper semi-continuous with weakly compact image. This contributes towards the solution of a problem posed by Godefroy, Montesinos and Zizler.
Money and happiness: does age make a difference?
Authors: HSIEH CHANG-MING 
Published: February 2011

ABSTRACTAlthough the factors that influence people's perception of happiness have long been a focus for scholars, research to date has not offered conclusive findings on the relationships between income, age and happiness. This study examined the relationship between money and happiness across age groups. Analysing data from United States General Social Surveys from 1972 to 2006, this study finds that even after controlling for all the major socio-demographic variables, income (whether household income or personal equivalised income) had a significant positive association with happiness for young and middle-age adults, but it was not the same case with older adults. After controlling for the major socio-demographic variables, there was no evidence of a significant relationship between income (whichever definition) and happiness for older adults. The results also showed that the effect of household income on happiness was significantly smaller for older adults than for young or middle-age adults in the model controlling for major socio-demographic variables. The relationship between household income and happiness no longer differed significantly across age groups after social comparison variables were included. The relationship between equivalised income and happiness did not vary significantly by age group after controlling for the major socio-demographic variables.