395 research outputs found
An Evaluation of Potential Compute Platforms for Picosatellites
What compute platform should picosatellites use? CubeSats, classified as nanosatellites, are transitioning from microcontrollers that cannot run modern operating systems and modern programming environments to Linux-capable compute platforms. As electronics continue to shrink, picosatellite missions are likely to become more common, perhaps using the PocketQube standard. This paper characterizes the requirements that compute platforms for picosatellites should satisfy and analyzes in detail 4 potential platforms. We show that suitable hardware does exist, but that it is not yet supported well enough to allow small teams to use it in satellites or other specialized sensor nodes
Regulation of CLL survival by hypoxia-inducible factor and its target genes
AbstractChronic lymphocytic leukemia (CLL), the most common adult leukemia in the Western world, is characterized by the progressive accumulation of small mature CD5+B lymphocytes in the peripheral blood, lymphoid organs, and bone marrow (BM). The main feature of the disease is decreased apoptosis, resulting in the pathologic accumulation of these malignant cells. Appropriate cellular responses to changes in oxygen tension during normal development or pathological processes, such as cardiovascular disease and cancer, are ultimately regulated by the transcription factor, hypoxia-inducible factor (HIF). Unlike their normal counterparts, CLL cells express HIF-1α even under normoxia. In addition, overexpression of HIF-1α has been observed in leukemic cells in BM specimens from CLL patients. The HIF transcription factor has been implicated in controlling the expression of a wide variety of genes implicated in apoptosis, angiogenesis, invasion, and metastasis. This review describes pathways regulating CLL survival with a focus on HIF-1α and its target genes, MIF and Midkine (MK), and the potential cross-talk between these factors
Gonadotropins in the Russian Sturgeon: Their Role in Steroid Secretion and the Effect of Hormonal Treatment on Their Secretion.
In the reproduction process of male and female fish, pituitary derived gonadotropins (GTHs) play a key role. To be able to specifically investigate certain functions of Luteinizing (LH) and Follicle stimulating hormone (FSH) in Russian sturgeon (Acipenser gueldenstaedtii; st), we produced recombinant variants of the hormones using the yeast Pichia pastoris as a protein production system. We accomplished to create in vitro biologically active heterodimeric glycoproteins consisting of two associated α- and β-subunits in sufficient quantities. Three dimensional modelling of both GTHs was conducted in order to study the differences between the two GTHs. Antibodies were produced against the unique β-subunit of each of the GTHs, in order to be used for immunohistochemical analysis and to develop an ELISA for blood and pituitary hormone quantification. This detection technique revealed the specific localization of the LH and FSH cells in the sturgeon pituitary and pointed out that both cell types are present in substantially higher numbers in mature males and females, compared to immature fish. With the newly attained option to prevent cross-contamination when investigating on the effects of GTH administration, we compared the steroidogeneic response (estradiol and 11-Keto testosterone (11-KT) in female and males, respectively) of recombinant stLH, stFSH, and carp pituitary extract in male and female sturgeon gonads at different developmental stages. Finally, we injected commercially available gonadotropin releasing hormones analog (GnRH) to mature females, and found a moderate effect on the development of ovarian follicles. Application of only testosterone (T) resulted in a significant increase in circulating levels of 11-KT whereas the combination of GnRH + T did not affect steroid levels at all. The response pattern for estradiol demonstrated a similar situation. FSH levels showed significant increases when GnRH + T was administered, while no changes were present in LH levels
Characterization of a novel fast-growing zebrafish: a new approach to growth hormone transgenesis
The manipulation of the somatotropic axis, governing growth, has been a focus of numerous transgenic approaches aimed at developing fast-growing fish for research, medicine and aquaculture purposes. However, the excessively high growth hormone (GH) levels in these transgenic fish often result in deformities that impact both fish health and consumer acceptance. In an effort to mitigate these issues and synchronize exogenous GH expression with reproductive processes, we employed a novel transgenic construct driven by a tilapia luteinizing hormone (LH) promoter. This approach was anticipated to induce more localized and lower exogenous GH secretion. In this study, we characterized the growth and reproduction of these transgenic LHp-GH zebrafish using hormonal and physiological parameters. Our findings reveal that LHp-GH fish exhibited accelerated growth in both length and weight, along with a lower feed conversion ratio, indicating more efficient feed utilization, all while maintaining unchanged body proportions. These fish demonstrated higher expression levels of LH and GH in the pituitary and elevated IGF-1 levels in the liver compared to wild-type fish. An examination of reproductive function in LHp-GH fish unveiled lower pituitary LH and FSH contents, smaller follicle diameter in female gonads, and reduced relative fecundity. However, in transgenic males, neither the distribution of spermatogenesis stages nor sperm concentrations differed significantly between the fish lines. These results suggest that coupling exogenous GH expression with endogenous LH expression in females directs resource investment toward somatic growth at the expense of reproductive processes. Consequently, we conclude that incorporating GH under the LH promoter represents a suitable construct for the genetic engineering of commercial fish species, providing accelerated growth while preserving body proportions
Statistics of Coulomb Blockade Peak Spacings within the Hartree-Fock Approximation
We study the effect of electronic interactions on the addition spectra and on
the energy level distributions of two-dimensional quantum dots with weak
disorder using the self-consistent Hartree-Fock approximation for spinless
electrons. We show that the distribution of the conductance peak spacings is
Gaussian with large fluctuations that exceed, in agreement with experiments,
the mean level spacing of the non-interacting system. We analyze this
distribution on the basis of Koopmans' theorem. We show furthermore that the
occupied and unoccupied Hartree-Fock levels exhibit Wigner-Dyson statistics.Comment: 5 pages, 2 figures, submitted for publicatio
Quantum-classical processing and benchmarking at the pulse-level
Towards the practical use of quantum computers in the NISQ era, as well as
the realization of fault-tolerant quantum computers that utilize quantum error
correction codes, pressing needs have emerged for the control hardware and
software platforms. In particular, a clear demand has arisen for platforms that
allow classical processing to be integrated with quantum processing. While
recent works discuss the requirements for such quantum-classical processing
integration that is formulated at the gate-level, pulse-level discussions are
lacking and are critically important. Moreover, defining concrete performance
benchmarks for the control system at the pulse-level is key to the necessary
quantum-classical integration. In this work, we categorize the requirements for
quantum-classical processing at the pulse-level, demonstrate these requirements
with a variety of use cases, including recently published works, and propose
well-defined performance benchmarks for quantum control systems. We utilize a
comprehensive pulse-level language that allows embedding universal classical
processing in the quantum program and hence allows for a general formulation of
benchmarks. We expect the metrics defined in this work to form a solid basis to
continue to push the boundaries of quantum computing via control systems,
bridging the gap between low-level and application-level implementations with
relevant metrics.Comment: 22 page
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Endogenous siRNAs promote proteostasis and longevity in germline-less Caenorhabditis elegans.
How lifespan and the rate of aging are set is a key problem in biology. Small RNAs are conserved molecules that impact diverse biological processes through the control of gene expression. However, in contrast to miRNAs, the role of endo-siRNAs in aging remains unexplored. Here, by combining deep sequencing and genomic and genetic approaches in Caenorhabditis elegans, we reveal an unprecedented role for endo-siRNA molecules in the maintenance of proteostasis and lifespan extension in germline-less animals. Furthermore, we identify an endo-siRNA-regulated tyrosine phosphatase, which limits the longevity of germline-less animals by restricting the activity of the heat shock transcription factor HSF-1. Altogether, our findings point to endo-siRNAs as a link between germline removal and the HSF-1 proteostasis and longevity-promoting somatic pathway. This establishes a role for endo siRNAs in the aging process and identifies downstream genes and physiological processes that are regulated by the endo siRNAs to affect longevity
Forty Five Percent of the Israeli Population were Infected with the Influenza B Victoria virus During the Winter season 2015-16
While infection with influenza A viruses has been extensively investigated, infections with influenza B viruses which are commonly categorized into the highly homologous Victoria and Yamagata lineages, are less studied, despite their considerable virulence. Here we used RT-PCR assays, hemagglutination inhibition assays and antibody titers to determine the levels of influenza B infection. We report of high influenza B Victoria virus prevalence in the 2015-16 winter season in Israel, affecting approximately half of the Israeli population. We further show that the Victoria B virus infected individuals of all ages and that it was present in the country throughout the entire winter season. The vaccine however included the inappropriate Yamagata virus. We propose that a quadrivalent vaccine, that includes both Yamagata and Victoria lineages, should be considered for future influenza vaccination
Addition Spectra of Chaotic Quantum Dots: Interplay between Interactions and Geometry
We investigate the influence of interactions and geometry on ground states of
clean chaotic quantum dots using the self-consistent Hartree-Fock method. We
find two distinct regimes of interaction strength: While capacitive energy
fluctuations follow approximately a random matrix prediction for
weak interactions, there is a crossover to a regime where is
strongly enhanced and scales roughly with interaction strength. This
enhancement is related to the rearrangement of charges into ordered states near
the dot edge. This effect is non-universal depending on dot shape and size. It
may provide additional insight into recent experiments on statistics of Coulomb
blockade peak spacings.Comment: 4 pages, final version to appear in Phys. Rev. Let
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