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 Wellenträgern mit Smartphone und Tablet-PC

In der Lehre ermöglichen Smartphones/Tablet-PCs aus messtechnischer Sicht durch interne Sensoren und durch die Verfügbarkeit geeigneter Anwendungsprogramme (Apps) vielfältige Messungen ausreichender Messgenauigkeit. Eine große Anzahl sensor- bzw. computerbasierter Messungen sind mittlerweile unter geringem Materialaufwand mit diesen mobilen Endgeräten durchführbar. Speziell in der Akustik erlauben Mikrofon, Lautsprecher und adäquate Apps Schallwellen zwischen 20 Hz und 24 kHz auszusenden, zu detektieren und akustische Größen in Echtzeit grafisch darzustellen und anschließend auszuwerten.Aus physikdidaktischer Sicht sind Smartphones/Tablet-PCs intuitiv handhabbare und für den Lernenden jederzeit verfügbare Experimentiermittel mit hohem motivationalem Potenzial. Insbesondere erweitern diese mobilen Messlabore für Lernende die Möglichkeiten zum eigenständigen Experimentieren.Am Beispiel akustischer Resonanzen in eindimensionalen endlichen Luftsäulen und Metallstäben werden Experimente für die Schul- und Hochschullehre vorgestellt, die mit Smartphones/Tablet-PCs und auf Verwendbarkeit geprüften Apps durchführbar sind. Darüber hinaus wird die Temperaturabhängigkeit der Schallgeschwindigkeit in Luft qualitativ und quantitativ untersucht sowie in Edelstahl bestimmt. Abschließend werden die Experimente unter physikdidaktischen Gesichtspunkten eingeordnet und diskutiert

Experimentelle Untersuchung akustischer Resonanzen in eindimensionalen Wellenträgern mit Smartphone und Tablet-PC

In der Lehre ermöglichen Smartphones/Tablet-PCs aus messtechnischer Sicht durch interne Sensoren und durch die Verfügbarkeit geeigneter Anwendungsprogramme (Apps) vielfältige Messungen ausreichender Messgenauigkeit. Eine große Anzahl sensor- bzw. computerbasierter Messungen sind mittlerweile unter geringem Materialaufwand mit diesen mobilen Endgeräten durchführbar. Speziell in der Akustik erlauben Mikrofon, Lautsprecher und adäquate Apps Schallwellen zwischen 20 Hz und 24 kHz auszusenden, zu detektieren und akustische Größen in Echtzeit grafisch darzustellen und anschließend auszuwerten.Aus physikdidaktischer Sicht sind Smartphones/Tablet-PCs intuitiv handhabbare und für den Lernenden jederzeit verfügbare Experimentiermittel mit hohem motivationalem Potenzial. Insbesondere erweitern diese mobilen Messlabore für Lernende die Möglichkeiten zum eigenständigen Experimentieren.Am Beispiel akustischer Resonanzen in eindimensionalen endlichen Luftsäulen und Metallstäben werden Experimente für die Schul- und Hochschullehre vorgestellt, die mit Smartphones/Tablet-PCs und auf Verwendbarkeit geprüften Apps durchführbar sind. Darüber hinaus wird die Temperaturabhängigkeit der Schallgeschwindigkeit in Luft qualitativ und quantitativ untersucht sowie in Edelstahl bestimmt. Abschließend werden die Experimente unter physikdidaktischen Gesichtspunkten eingeordnet und diskutiert

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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

How flat is an air-cleaved mica surface?

Ostendorf F, Schmitz C, Hirth S, Kühnle A, Kolodziej JJ, Reichling M. How flat is an air-cleaved mica surface? Nanotechnology. 2008;19(30):305705.Muscovite mica is an important mineral that has become a standard substrate, due to its easy cleavage along the {001} planes, revealing a very flat surface that is compatible with many biological materials. Here we study mica surfaces by dynamic atomic force microscopy (AFM) operated in the non-contact mode (NC-AFM) under ultra-high vacuum (UHV) conditions. Surfaces produced by cleaving in UHV cannot be imaged with NC-AFM due to large surface charges; however, cleavage in air yields much less surface charge and allows for NC-AFM imaging. We present highly resolved NC-AFM images of air-cleaved mica surfaces revealing a rough morphology originating from a high density of nanometre-sized particles. Among these particles, we find regularly shaped structures indicating the growth of crystallites on the surface. The contamination layer cannot be removed by degassing in UHV; even prolonged heating at a temperature of 560 K under UHV conditions does not yield an atomically flat surface