293 research outputs found
THE PHYSICIAN LABOR MARKET IN A MANAGED CARE-DOMINATED ENVIRONMENT
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74586/1/j.1465-7295.1999.tb01430.x.pd
Mice Transgenic for the Human Carcinoembryonic Antigen Gene Maintain Its Spatiotemporal Expression Pattern
The tumor marker carcinoembryonic antigen (CEA) is predominantly expressed in epithelial cells along the gastrointestinal tract and in a variety of adenocarcinomas. As a basis for investigating its in vivo regulation and for establishing an animal model for tumor immunotherapy, transgenic mice were generated with a 33-kilobase cosmid clone insert containing the complete human CEA gene and flanking sequences. CEA was found in the tongue, esophagus, stomach, small intestine, cecum, colon, and trachea and at low levels in the lung, testis, and uterus of adult mice of independent transgenic strains. CEA was first detected at day 10.5 of embryonic development (embryonic day 10.5) in primary trophoblast giant cells and was found in the developing gut, urethra, trachea, lung, and nucleus pulposus of the vertebral column from embryonic day 14.5 onwards. From embryonic day 16.5 CEA was also visible in the nasal mucosa and tongue. Because this spatiotemporal expression pattern correlates well with that known for humans, it follows that the transferred genomic region contains all of the regulatory elements required for the correct expression of CEA. Furthermore, although mice apparently lack an endogenous CEA gene, the entire repertoire of transcription factors necessary for correct expression of the CEA transgene is conserved between mice and humans. After tumor induction, these immunocompetent mice will serve as a model for optimizing various forms of immunotherapy, using CEA as a target antigen
Nucleation and growth of platelets in hydrogen-ion-implanted silicon
H ion implantation into crystalline Si is known to result in the precipitation of planar defects in the form of platelets. Hydrogen-platelet formation is critical to the process that allows controlled cleavage of Si along the plane of the platelets and subsequent transfer and integration of thinly sliced Si with other substrates. Here we show that H-platelet formation is controlled by the depth of the radiation-induced damage and then develop a model that considers the influence of stress to correctly predict platelet orientation and the depth at which platelet nucleation density is a maximum.This work was supported
by the U.S. Department of Energy, Office of Basic
Energy Sciences
Experimentelle Untersuchung akustischer Resonanzen in eindimensionalen WellentrÀgern mit Smartphone und Tablet-PC
In der Lehre ermöglichen Smartphones/Tablet-PCs aus messtechnischer Sicht durch interne Sensoren und durch die VerfĂŒgbarkeit geeigneter Anwendungsprogramme (Apps) vielfĂ€ltige Messungen ausreichender Messgenauigkeit. Eine groĂe Anzahl sensor- bzw. computerbasierter Messungen sind mittlerweile unter geringem Materialaufwand mit diesen mobilen EndgerĂ€ten durchfĂŒhrbar. Speziell in der Akustik erlauben Mikrofon, Lautsprecher und adĂ€quate Apps Schallwellen zwischen 20 Hz und 24 kHz auszusenden, zu detektieren und akustische GröĂen in Echtzeit grafisch darzustellen und anschlieĂend auszuwerten.Aus physikdidaktischer Sicht sind Smartphones/Tablet-PCs intuitiv handhabbare und fĂŒr den Lernenden jederzeit verfĂŒgbare Experimentiermittel mit hohem motivationalem Potenzial. Insbesondere erweitern diese mobilen Messlabore fĂŒr Lernende die Möglichkeiten zum eigenstĂ€ndigen Experimentieren.Am Beispiel akustischer Resonanzen in eindimensionalen endlichen LuftsĂ€ulen und MetallstĂ€ben werden Experimente fĂŒr die Schul- und Hochschullehre vorgestellt, die mit Smartphones/Tablet-PCs und auf Verwendbarkeit geprĂŒften Apps durchfĂŒhrbar sind. DarĂŒber hinaus wird die TemperaturabhĂ€ngigkeit der Schallgeschwindigkeit in Luft qualitativ und quantitativ untersucht sowie in Edelstahl bestimmt. AbschlieĂend werden die Experimente unter physikdidaktischen Gesichtspunkten eingeordnet und diskutiert
Experimentelle Untersuchung akustischer Resonanzen in eindimensionalen WellentrÀgern mit Smartphone und Tablet-PC
In der Lehre ermöglichen Smartphones/Tablet-PCs aus messtechnischer Sicht durch interne Sensoren und durch die VerfĂŒgbarkeit geeigneter Anwendungsprogramme (Apps) vielfĂ€ltige Messungen ausreichender Messgenauigkeit. Eine groĂe Anzahl sensor- bzw. computerbasierter Messungen sind mittlerweile unter geringem Materialaufwand mit diesen mobilen EndgerĂ€ten durchfĂŒhrbar. Speziell in der Akustik erlauben Mikrofon, Lautsprecher und adĂ€quate Apps Schallwellen zwischen 20 Hz und 24 kHz auszusenden, zu detektieren und akustische GröĂen in Echtzeit grafisch darzustellen und anschlieĂend auszuwerten.Aus physikdidaktischer Sicht sind Smartphones/Tablet-PCs intuitiv handhabbare und fĂŒr den Lernenden jederzeit verfĂŒgbare Experimentiermittel mit hohem motivationalem Potenzial. Insbesondere erweitern diese mobilen Messlabore fĂŒr Lernende die Möglichkeiten zum eigenstĂ€ndigen Experimentieren.Am Beispiel akustischer Resonanzen in eindimensionalen endlichen LuftsĂ€ulen und MetallstĂ€ben werden Experimente fĂŒr die Schul- und Hochschullehre vorgestellt, die mit Smartphones/Tablet-PCs und auf Verwendbarkeit geprĂŒften Apps durchfĂŒhrbar sind. DarĂŒber hinaus wird die TemperaturabhĂ€ngigkeit der Schallgeschwindigkeit in Luft qualitativ und quantitativ untersucht sowie in Edelstahl bestimmt. AbschlieĂend werden die Experimente unter physikdidaktischen Gesichtspunkten eingeordnet und diskutiert
iMobilePhysics: Seamless Learning durch Experimente mit Smartphones & Tablets in Physik
Der Beitrag erlĂ€utert ein Nutzungskonzept fĂŒr Smartphones und Tablets als physikalische Experimentiermittel (iMobilePhysics, kurz: iMP) und ordnet zwei Realisierungsbeispiele dieses Konzept fĂŒr Schule und Hochschule an Hand von Designkriterien in den Rahmen des Mobile Assisted Seamless Learning (MSL) ein. Zu den Beispielen werden Studien zur Lernwirksamkeit und Akzeptanz der medienbasierten LehransĂ€tze dargestellt. Die Ergebnisse liefern den BegrĂŒndungsrahmen, mobiles Experimentieren mit Smartphone und Tablets zur UnterstĂŒtzung von MSL in die schulische und universitĂ€re Lehre, insbesondere in die Lehramtsausbildung einzubinden.
12.08.2016 | Michael Hirth, Jochen Kuhn, Andreas MĂŒller, Matthias Rohs & Pascal Klein (Kaiserslautern, Genf
Crowdsourcing Technology to Support Academic Research
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Force-matched embedded-atom method potential for niobium
Large-scale simulations of plastic deformation and phase transformations in
alloys require reliable classical interatomic potentials. We construct an
embedded-atom method potential for niobium as the first step in alloy potential
development. Optimization of the potential parameters to a well-converged set
of density-functional theory (DFT) forces, energies, and stresses produces a
reliable and transferable potential for molecular dynamics simulations. The
potential accurately describes properties related to the fitting data, and also
produces excellent results for quantities outside the fitting range. Structural
and elastic properties, defect energetics, and thermal behavior compare well
with DFT results and experimental data, e.g., DFT surface energies are
reproduced with less than 4% error, generalized stacking-fault energies differ
from DFT values by less than 15%, and the melting temperature is within 2% of
the experimental value.Comment: 17 pages, 13 figures, 7 table
Transcriptional signature of an adult brain tumor in Drosophila.
BACKGROUND: Mutations and gene expression alterations in brain tumors have been extensively investigated, however the causes of brain tumorigenesis are largely unknown. Animal models are necessary to correlate altered transcriptional activity and tumor phenotype and to better understand how these alterations cause malignant growth. In order to gain insights into the in vivo transcriptional activity associated with a brain tumor, we carried out genome-wide microarray expression analyses of an adult brain tumor in Drosophila caused by homozygous mutation in the tumor suppressor gene brain tumor (brat). RESULTS: Two independent genome-wide gene expression studies using two different oligonucleotide microarray platforms were used to compare the transcriptome of adult wildtype flies with mutants displaying the adult bratk06028 mutant brain tumor. Cross-validation and stringent statistical criteria identified a core transcriptional signature of brat(k06028) neoplastic tissue. We find significant expression level changes for 321 annotated genes associated with the adult neoplastic brat(k06028) tissue indicating elevated and aberrant metabolic and cell cycle activity, upregulation of the basal transcriptional machinery, as well as elevated and aberrant activity of ribosome synthesis and translation control. One fifth of these genes show homology to known mammalian genes involved in cancer formation. CONCLUSION: Our results identify for the first time the genome-wide transcriptional alterations associated with an adult brain tumor in Drosophila and reveal insights into the possible mechanisms of tumor formation caused by homozygous mutation of the translational repressor brat.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Role of density fluctuations in the relaxation of random dislocation systems
We study the relaxation dynamics of systems of straight, parallel crystal
dislocations, starting from initially random and uncorrelated positions of the
individual dislocations. A scaling model of the relaxation process is
constructed by considering the gradual extinction of the initial density
fluctuations present in the system. The model is validated by ensemble
simulations of the discrete dynamics of dislocations. Convincing agreement is
found for systems of edge dislocations in single slip irrespective of the net
Burgers vector of the dislocation system. It is also demonstrated that the
model does not work in multiple slip geometries.Comment: 25 pages, 11 figures; submitted to Journal of Statistical Mechanics:
theory and experiment after 2nd round of referenc
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