Developmental regulation of expression of the lactate dehydrogenase (LDH) multigene family during mouse spermatogenesis

Expression of the Lactate Dehydrogenase (LDH) genes during various stages of spermatogenesis was studied by using a combination of Northern blot analyses and in situ hybridization techniques. These studies have indicated that developmentally programmed expression of all three functional LDH genes occurs during differentiation of germ cells. The LDH/C (ldh-3) gene was expressed exclusively during meiosis and spermiogenesis, beginning in leptotene/zygotene spermatocytes and continuing through to the elongated spermatids. LDH/C (ldh-3) gene expression was accompanied by transient expression of the LDH/A (ldh-1) gene in pachytene spermatocytes and round spermatids. The LDH/B (ldh-2) gene was expressed mainly in Sertoli and spermatogonial cells. By using somatic cell hybrids, the LDH/C (ldh-3) gene has been mapped to mouse chromosome 7, establishing that it is syntenic with the LDH/A (ldh-1) gene locus. Experimental observations made in this study provide new insight into the order and sequence of events involved in the regulation of gene expression of the LDH gene family during spermatogenesis

Low power, compact charge coupled device signal processing system

A variety of charged coupled devices (CCDs) for performing programmable correlation for preprocessing environmental sensor data preparatory to its transmission to the ground were developed. A total of two separate ICs were developed and a third was evaluated. The first IC was a CCD chirp z transform IC capable of performing a 32 point DFT at frequencies to 1 MHz. All on chip circuitry operated as designed with the exception of the limited dynamic range caused by a fixed pattern noise due to interactions between the digital and analog circuits. The second IC developed was a 64 stage CCD analog/analog correlator for performing time domain correlation. Multiplier errors were found to be less than 1 percent at designed signal levels and less than 0.3 percent at the measured smaller levels. A prototype IC for performing time domain correlation was also evaluated

Erosion protection benefits of stabilized SnF2 dentifrice versus an arginine–sodium monofluorophosphate dentifrice:results from in vitro and in situ clinical studies

OBJECTIVES: The aim of these investigations was to assess the ability of two fluoride dentifrices to protect against the initiation and progression of dental erosion using a predictive in vitro erosion cycling model and a human in situ erosion prevention clinical trial for verification of effectiveness. MATERIALS AND METHODS: A stabilized stannous fluoride (SnF(2)) dentifrice (0.454 % SnF(2) + 0.077 % sodium fluoride [NaF]; total F = 1450 ppm F) [dentifrice A] and a sodium monofluorophosphate [SMFP]/arginine dentifrice (1.1 % SMFP + 1.5 % arginine; total F = 1450 ppm F) [dentifrice B] were tested in a 5-day in vitro erosion cycling model and a 10-day randomized, controlled, double-blind, two-treatment, four-period crossover in situ clinical trial. In each study, human enamel specimens were exposed to repetitive product treatments using a standardized dilution of test products followed by erosive acid challenges in a systematic fashion. RESULTS: Both studies demonstrated statistically significant differences between the two products, with dentifrice A providing significantly better enamel protection in each study. In vitro, dentifrice A provided a 75.8 % benefit over dentifrice B (p < 0.05, ANOVA), while after 10 days in the in situ model, dentifrice A provided 93.9 % greater protection versus dentifrice B (p < 0.0001, general linear mixed model). CONCLUSION: These results support the superiority of stabilized SnF(2) dentifrices for protecting human teeth against the initiation and progression of dental erosion. CLINICAL RELEVANCE: Stabilized SnF(2) dentifrices may provide more significant benefits to consumers than conventional fluoride dentifrices

Mothering and Professing in the Ivory Tower: Supporting Graduate Student Mothers

Women interested in becoming professors and mothers are often unsure of the besttime to start their families. Many women decide to become mothers in graduateschool. This article discusses the landscape for graduate students who decide to becomemothers ( gsm s) while still in school. There are several obstacles for gsm s who wishto become tenured faculty members. Institutional obstacles include the notion of idealworkers and ideal careers, which do not include the option of motherhood and oftenconflict with the notion of the ideal mother. Another obstacle is institutional genderbiases and assumptions about women, such as the bias against caregiving. Womenof any age are assumed to be responsible for caregiving of children and/or elders.Finally, women lack their own individual agency and do not have family supportto be able to be successful. gsm s can employ various strategies to overcome theseobstacles. Strategies can include institutional change strategies, department support,individual agency, and family support. Obstacles and strategies are illustrated throughpersonal vignettes from the authors’ own experiences: three authors are tenured withchildren, and two have infants and are gsm s. Two authors are or have been chairsof dissertation committees. Recommendations for institutions are offered that cansupport gsm s in their efforts to be successful at mothering and professing in theivory tower. The presented arguments make it clear that the mothering viewpointis sorely needed in the academy, and that gsm s need support from all stakeholdersin order to be successful

Electrokinetic Potentials at Liquid Surfaces

Aqueous solutions of potassium chloride were allowed to flow through air. The solutions were from 10-1 N to 10-7N. The hydrostatic pressure was from 23 to 80 cm. of solution. The flow was vertical and laminar, through a circular aperture in a thin platinum disc on to a second platinum disc. The diameter of the aperture was 0.05 cm. The discs served as electrodes. The potential difference was measured with a vacuum tube potentiometer. A F.P. 54 G. E. tube was used, so the potential difference was measured with essentially no current flow

A method for volume stabilization of single, dye-doped water microdroplets with femtoliter resolution

A self-control mechanism that stabilizes the size of Rhodamine B-doped water microdroplets standing on a superhydrophobic surface is demonstrated. The mechanism relies on the interplay between the condensation rate that was kept constant and evaporation rate induced by laser excitation which critically depends on the size of the microdroplets. The radii of individual water microdroplets (>5 um) stayed within a few nanometers during long time periods (up to 455 seconds). By blocking the laser excitation for 500 msec, the stable volume of individual microdroplets was shown to change stepwise.Comment: to appear in the J. Op. Soc. Am.

Leukotriene C4 biosynthesis in isolated August rat peritoneal leukocytes

The mixed leukocyte population obtained from the peritoneum of the August rat is a potentially important experimental model of inherent eosinophilia that has not been well characterized. In the present study, isolated cell preparations generated a concentration-dependent release of leukotriene (LT) C4 when exposed to the Ca2+ ionophore A23187, reaching maximal stimulation at 5.0 μM. This response was inhibited by the 5-lipoxygenase activating protein antagonist MK-886 (0.1 μM), nominally Ca2+ and Mg2+-free incubation media and by activation of protein kinase C via phorbol 12-myristate 13-acetate (50 nM). These findings establish a model system for investigating LTC4 profiles contingent with innate peritoneal eosinophilia and are consistent with the hypothesis that cellular LTC4 biosynthesis is phosphoregulated

Applying a community entrepreneurship development (CED) framework

This article develops a community entrepreneurship development (CED) framework and illustrates its use in a case study of the current and potential value of agriculture to the Barossa Valley in South Australia. The CED offers a framework for rural regional development that both practitioners and policymakers can use to develop and leverage entrepreneurial competencies and other forms of community capital to foster entrepreneurship at the community level. It assesses the potential for leveraging Emery and Flora’s [(2006). Spiraling-up: Mapping community transformation with community capitals framework. Community Development, 37(1), 19–35] community capital framework to build entrepreneurship and innovation. The findings suggest that the success of firm-level entrepreneurship is often dependent upon leveraging the rural region’s idiosyncratic natural capitals with human and social/entrepreneurial capitals to result in community-level entrepreneurial market development initiatives

Mussurana bicolor (Peracca, 1904) (Squamata, Colubridae): additional country records and first list of voucher specimens from Bolivia

We present country records and a list of voucher specimens for Mussurana bicolor (Peracca, 1904) (Serpentes, Colubridae) from Bolivia. There is scarce information on museum specimens and locality data from Bolivia for this species in the scientific literature. Additionally, we discuss two newly collected specimens from the Llanos de Moxos, a floodplain in the Beni Department. This account contributes to the knowledge of the northwestern distributional status of M. bicolor and summarizes available data for Bolivia

A Conserved Bicycle Model for Circadian Clock Control of Membrane Excitability

SummaryCircadian clocks regulate membrane excitability in master pacemaker neurons to control daily rhythms of sleep and wake. Here, we find that two distinctly timed electrical drives collaborate to impose rhythmicity on Drosophila clock neurons. In the morning, a voltage-independent sodium conductance via the NA/NALCN ion channel depolarizes these neurons. This current is driven by the rhythmic expression of NCA localization factor-1, linking the molecular clock to ion channel function. In the evening, basal potassium currents peak to silence clock neurons. Remarkably, daily antiphase cycles of sodium and potassium currents also drive mouse clock neuron rhythms. Thus, we reveal an evolutionarily ancient strategy for the neural mechanisms that govern daily sleep and wake