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Integration of microwave sources and detection circuits has led to the design of very compact electron paramagnetic resonance (EPR) instruments, so-called EPR on-a-chip (EPRoC). As recently demonstrated, this approach also offers opportunities for electrical detection of magnetic resonance (EDMR), a variant of EPR in which the magnetic resonance effect is detected via changes in the electrical properties of materials or devices. Here, we report the demonstration of EDMRoC on lateral SiC MOSFETs under charge pumping (CP) conditions. The detected CP current gives direct access to microscopic information about the recombination centers within the transistor gate inversion region under the gate dielectric. Efficient and selective microwave excitation of the region of interest of the device can be obtained by only modest modifications to both the MOSFET and the EPRoC electronic board. A comparative study between EDMRoC and a traditional resonant cavity configuration reveals comparable signal-to-noise ratios for CP-detected EDMR spectra. In addition to space- and cost-efficiency, EDMRoC offers alternative detection modes with scanning and modulation of the microwave frequency, as well as potentially easier sample mounting and exchange. We end with a discussion of the advantages, limitations, and perspectives of the EDMRoC set-up compared to EDMR in a conventional EPR spectrometer. [ABSTRACT FROM AUTHOR]

Absence of spermiogenesis in mice with meiotic defects complicates the staging of meiotic arrest using light microscopy. Consequently, new methodologies are required to establish accurate relationships among germ cells. In this study, we utilized a novel approach to analyze germ cell degeneration in juvenile mice. We used terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) in combination with meiosis-specific antibodies. Germ cell degeneration is a normal component of early spermatogenesis in juvenile mice. The incidence of germ cell death was monitored at various postnatal ages of mice using the TUNEL assay to quantify the incidence of apoptosis. Cell death occurred predominantly at 15.5 days after birth. It was found that groups of apoptotic cells were apparent in tubules containing two generations of spermatocytes that form in two progressive cohorts. Electron microscopic observations further illustrated that the majority of cells in the first cohort are in late pachytene, while groups of cells in the second cohort can degenerate in early pachytene. The methodology utilized in this study is significant because it allows one to accurately determine the point at which germ cells arrest. Consequently, we believe that these methods can be applied to study animals with meiotic defects that prevent spermiogenesis. Key words: spermatogenesis, cycle of seminiferous epithelium, mouse meiosis, apoptosis, immunocytology. L'absence de spermiogenese chez la souris presentant des defauts meiotiques complique l'etablissement du stade d'arret meiotique en microscopie. Consequemment, de nouvelles methodes sont necessaires pour etablir avec precision les relations entre cellules germinales. Dans ce travail, les auteurs ont employe une nouvelle approche pour analyser la degenerescence des cellules germinales chez les souris juveniles. Les auteurs ont employe le marquage de l'encoche a l'aide de la dUTP transferase terminale (ou TUNEL de l'anglais << terminal transferase dUTP nick end labeling >>) combine a l'emploi d'anticorps specifiques a la meiose. La mort des cellules germinales a ete suivie a divers ages postnataux chez les souris en utilisant l'analyse TUNEL pour quantifier l'incidence de l'apoptose. La mort cellulaire s'est produite principalement 15,5 jours apres la naissance. Il a ete observe que des groupes de cellules en apoptose etaient visibles au sein de tubules contenant deux generations de spermatocytes, issues de deux cohortes successives. Des observations en microscopie electronique ont permis de conclure que la majorite des cellules de la premiere cohorte etaient en fin de pachytene tandis que des groupes de cellules de la seconde cohorte peuvent degenerer au debut du pachytene. La methode employee dans ce travail est importante car elle permet de determiner avec precision le stade auquel sont arretees des cellules germinales. En consequence, les auteurs pensent que ces methodes pourraient s'appliquer a d'autres animaux avec des defauts meiotiques qui empechent la spermiogenese. Mots-cles: spermatogenese, cycle de l'epithelium seminifere, meiose chez la souris, apoptose, immunocytologie. [Traduit par la Redaction], Mouse spermatogenesis begins shortly after birth when gonocytes give rise to spermatogonia (Vergouwen et al. 1991). Light microscopy studies indicate that spermatogonia undergo mitotic divisions in the mouse seminiferous epithelium [...]

An n-type lateral insulated gate bipolar transistor (nLIGBT) with double buried layer structure integrated in an existing smart-power junction-isolated technology is analyzed. This device is compared to the rivaling drain extended MOSFET transistor in smart-power junction-isolated technology.

In most eukaryotes, recombination of homologous chromosomes during meiosis is necessary for proper chromosome pairing and subsequent segregation. The molecular mechanisms of meiosis are still relatively unknown, but numerous genes are known to be involved, among which are many mismatch repair genes. One of them, mlh1, colocalizes with presumptive sites of crossing over, but its exact action remains unclear. We studied meiotic processes in a knockout line for mlh1 in zebrafish. Male mlh1 mutants are sterile and display an arrest in spermatogenesis at metaphase I, resulting in increased testis weight due to accumulation of prophase I spermatocytes. In contrast, females are fully fertile, but their progeny shows high rates of dysmorphology and mortality within the first days of development. SNP-based chromosome analysis shows that this is caused by aneuploidy, resulting from meiosis I chromosomal missegregation. Surprisingly, the small percentage of progeny that develops normally has a complete triploid genome, consisting of both sets of maternal and one set of paternal chromosomes, As adults, these triploid fish are infertile males with wild-type appearance. The frequency of triploid progeny of mlh1 mutant females is much higher than could be expected for random chromosome segregation. Together, these results show that multiple solutions exist for meiotic crossover/segregation problems.

Abstract: With immunofluorescence microscopy, the positions of centromeres and MLH1 (MutL homolog) foci representing the sites of presumptive chiasmata are shown for zebrafish (Danio rerio Hamilton 1822) synaptonemal complexes (SCs) [...]

Several examples of proteins exhibiting functional differentiation between somatic DNA repair and meiotic homologous recombination are presented. Somatic repair functions and meiotic recombination diverged during evolution resulting in adaptations specific to sexual reproduction.

An investigation of the dynamics of integrated vertical DMOS transistors under 100-ns transmission line pulsing (TLP) stress is conducted using on-wafer TLP and TLM measurements. A traveling filament along the device width is observed, the traveling speed being estimated to be between 370 and 48z`0 m/s.

The degradation of a n-type lateral DMOS transistor is shown to be related to the injection of hot holes in the drift region field oxide. A new degradation model using the bulk current as the driving force reproduces the saturation effects observed in the parameter shifts.

The acquisition of genomic methylation in the male germ line is initiated prenatally in diploid gonocytes, while DNA methylation in the female germ line is initiated postnatally in growing oocytes. We compared the temporal expression patterns of the DNA methyltransferases, DNMT1, DNMT3a, DNMT3b, and DNMT31 in the male and female germ lines. DNMT1 expression was examined by immunocytochemistry and Northerns with an emphasis on the prenatal period. In the female, there is a gradual down-regulation of DNMT1 protein in prenatal meiotic prophase I oocytes that is not associated with the production of an untranslated transcript, as it is in the male; these results suggest that the mechanism of meiotic down-regulation differs between the sexes. In the male, DNMT1 is unlikely to play a role in the prenatal acquisition of germ line methylation patterns since it is down-regulated in gonocytes between 14.5 and 18.5 days of gestation and is absent at the time of initiation of DNA methylation. To search for candidate DNMTs that could be involved in establishing methylation patterns in both germ lines, real-time RT-PCR was used to simultaneously study the expression profiles of the three DNMT3 enzymes in developing testes and ovaries; DNMT1 expression was included as a control. Expression profiles of DNMT3a and DNMT31 provide support for an interaction of the two enzymes during prenatal germ cell development and de novo methylation in the male. DNMT31 is the predominant DNMT3 enzyme expressed at high levels in the postnatal female germ line at the time of acquisition of DNA methylation patterns. DNMT1 and DNMT3b expression levels peak concomitantly, shortly after birth in the male, consistent with a role in the maintenance of methylation patterns in proliferating spermatogonia. Together, the results provide clues to specific roles for the different DNMT family members in de novo and maintenance methylation in the developing testis and ovary. Keywords: DNA methyltransferases; DNMT1; DNMT3a; DNMT3b; DNMT31; Germ line; DNA methylation; Mouse; Real-time RT-PCR

The hot-carrier degradation behavior of both lateral and vertical integrated DMOS is investigated in detail by the analysis of the electrical data, charge pumping measurements and two-dimensional device simulations. Findings show that due to the specific nature of the vertical DMOS (VDMOS) device, the hot hole injection is absent in the device and the channel N(sub it) formation is substantially lower in the VDMOS.

With the phosphatase inhibitor, okadaic acid, we induce the precocious onset of the chiasmate stage and under those conditions show that the recombination nodules, MLH1 and MLH3 foci, are localized to the chiasmata. It is concluded that MLH1/3 foci are appropriate markers for the studies of crossovers/ chiasmata development and distribution at late meiotic prophase.

Mouse and human homologs of the Schizosaccharomyces pombe DNA damage checkpoint control gene rad1+ and the Saccharomyces cerevisiae homolog RAD17 have been identified. A link to meiosis in mammals and to checkpoint controlexists and its seems the yeast events are highly conserved in humans. HRAD1 is on chromosome 5p13 and is most homologous to S. pombe rad1+.