1,252 research outputs found

    Multipotent Genetic Suppression of Retrotransposon-Induced Mutations by Nxf1 through Fine-Tuning of Alternative Splicing

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    Cellular gene expression machinery has coevolved with molecular parasites, such as viruses and transposons, which rely on host cells for their expression and reproduction. We previously reported that a wild-derived allele of mouse Nxf1 (Tap), a key component of the host mRNA nuclear export machinery, suppresses two endogenous retrovirus-induced mutations and shows suggestive evidence of positive selection. Here we show that Nxf1CAST suppresses a specific and frequent class of intracisternal A particle (IAP)-induced mutations, including Ap3d1mh2J, a model for Hermansky-Pudlak syndrome, and Atcayhes, an orthologous gene model for Cayman ataxia, among others. The molecular phenotype of suppression includes ∼two-fold increase in the level of correctly-spliced mRNA and a decrease in mutant-specific, alternatively-processed RNA accumulating from the inserted allele. Insertional mutations involving ETn and LINE elements are not suppressed, demonstrating a high degree of specificity to this suppression mechanism. These results implicate Nxf1 in some instances of pre-mRNA processing, demonstrate the useful range of Nxf1CAST alleles for manipulating existing mouse models of disease, and specifically imply a low functional threshold for therapeutic benefit in Cayman ataxia

    Qualification of Electrical Ground Support Equipment for New Space Programs

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    With the Space Shuttle program coming to an end, the National Aeronautics and Space Administration (NASA) is moving to a new space flight program that will allow expeditions beyond low earth orbit. The space vehicles required to comply with these missions will be carrying heavy payloads. This implies that the Earth departure stage capabilities must be of higher magnitudes, given the current propulsion technology. The engineering design of the new flight hardware comes with some structural, thermal, propulsion and other subsystems' challenges. Meanwhile, the necessary ground support equipment (GSE) used to test, validate, verify and process the flight hardware must withstand the new program specifications. This paper intends to provide the qualification considerations during implementation of new electrical GSE for space programs. A team of engineers was formed to embark on this task, and facilitate the logistics process and ensure that the electrical, mechanical and fluids subsystems conduct the proper level of testing. Ultimately, each subsystem must certify that each piece of ground support equipment used in the field is capable of withstanding the strenuous vibration, acoustics, environmental, thermal and Electromagnetic Interference (EMf) levels experienced during pre-launch, launch and post-launch activities. The benefits of capturing and sharing these findings will provide technical, cost savings and schedule impacts infon11ation to both the technical and management community. Keywords: Qualification; Testing; Ground Support Equipment; Electromagnetic Interference Testing; Vibration Testing; Acoustic Testing; Power Spectral Density

    Evidence for quantum confinement in the photoluminescence of porous Si and SiGe

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    We have used anodization techniques to process porous surface regions in p-type Czochralski Si and in p-type Si0.85Ge0.15 epitaxial layers grown by molecular beam epitaxy. The SiGe layers were unrelaxed before processing. We have observed strong near-infrared and visible light emission from both systems. Analysis of the radiative and nonradiative recombination processes indicate that the emission is consistent with the decay of excitons localized in structures of one or zero dimensions

    Method for molding articles having non-planar portions from matted wood flakes

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    An article having non-planar portions, such as a pallet having a substantially flat deck member and a plurality of hollow leg members projecting integrally from the deck member, is molded as a one-piece unit from a loosely-felted, layered mat formed from a mixture of a resinous particle board binder and flake-like wood particles. The wood flakes have an average length of about 11/4 to about 6 inches, preferably about 2 to about 3 inches, an average thickness of about 0.005 to about 0.075 inch, preferably about 0.015 to about 0.025 inch, and an average width of 3 inches or less and no greater than the average length. Each layer of wood flakes in the mat lie substantially flat on a plane generally parallel to the major plane thereof and are randomly oriented to each other. The mat is placed between the male and female dies of a mold or press and compressed therein to substantially the desired shape under temperature and pressure conditions sufficient to bond the flakes together.https://digitalcommons.mtu.edu/patents/1118/thumbnail.jp

    Pallets molded from matted wood flakes

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    An article having non-planar portions, such as a pallet having a substantially flat deck member and a plurality of hollow leg members projecting integrally from the deck member, is molded as a one-piece unit from a loosely-felted, layered mat formed from a mixture of a resinous particle board binder and flake-like wood particles. The wood flakes have an average length of about 11/4 to about 6 inches, preferably about 2 to about 3 inches, an average thickness of about 0.005 to about 0.075 inch, preferably about 0.015 to about 0.025 inch, and an average width of 3 inches or less and no greater than the average length. Each layer of wood flakes in the mat lie substantially flat on a plane generally parallel to the major plane thereof and are randomly oriented to each other. The mat is placed between the male and female dies of a mold or press and compressed therein to substantially the desired shape under temperature and pressure conditions sufficient to bond the flakes together.https://digitalcommons.mtu.edu/patents/1125/thumbnail.jp

    Neuron-Specific HuR-Deficient Mice Spontaneously Develop Motor Neuron Disease

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    Human Ag R (HuR) is an RNA binding protein in the ELAVL protein family. To study the neuron-specific function of HuR, we generated inducible, neuron-specific HuR-deficient mice of both sexes. After tamoxifen-induced deletion of HuR, these mice developed a phenotype consisting of poor balance, decreased movement, and decreased strength. They performed significantly worse on the rotarod test compared with littermate control mice, indicating coordination deficiency. Using the grip-strength test, it was also determined that the forelimbs of neuron-specific HuR-deficient mice were much weaker than littermate control mice. Immunostaining of the brain and cervical spinal cord showed that HuR-deficient neurons had increased levels of cleaved caspase-3, a hallmark of cell apoptosis. Caspase-3 cleavage was especially strong in pyramidal neurons and α motor neurons of HuR-deficient mice. Genome-wide microarray and real-time PCR analysis further indicated that HuR deficiency in neurons resulted in altered expression of genes in the brain involved in cell growth, including trichoplein keratin filament-binding protein, Cdkn2c, G-protein signaling modulator 2, immediate early response 2, superoxide dismutase 1, and Bcl2. The additional enriched Gene Ontology terms in the brain tissues of neuron-specific HuR-deficient mice were largely related to inflammation, including IFN-induced genes and complement components. Importantly, some of these HuR-regulated genes were also significantly altered in the brain and spinal cord of patients with amyotrophic lateral sclerosis. Additionally, neuronal HuR deficiency resulted in the redistribution of TDP43 to cytosolic granules, which has been linked to motor neuron disease. Taken together, we propose that this neuron-specific HuR-deficient mouse strain can potentially be used as a motor neuron disease model

    Water & Nutrient Stress Increase Root Exudation

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    A presentation on how to develop procedures to grow healthy plants under sterile conditions, manipulate root exudation with stress, and quantify total organic carbon in exudates and determine composition of exudates using GC-MS

    The ClC-KbT481S chloride channel gene polymorphism, ischaemic stroke and hypertension

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    Stroke is a polygenic disorder. Previous genetic studies focused on candidate genes influencing pathogenic processes, with little emphasis on genes influencing vascular risk factors. Previous research linked the ClC-KbT481S poly- morphism to blood pressure (BP). We therefore undertook an association study to determine the relevance of this poly- morphism to stroke, particularly lacunar stroke, given its strong correlation with hypertension. We genotyped DNA from 180 patients with acute ischaemic stroke (44 having lacunar stroke) and 298 age- and gender-matched controls using a se- quence-specific polymerase chain reaction method (SS-PCR). We found no association between the ClC-KbT481S poly- morphism and ischaemic stroke (Odds Ratio (OR): 0.87, 95% Confidence Interval (CI): 0.57-1.33). Stratification for stroke subtype did not alter this finding. This polymorphism showed a borderline association with history of hypertension (p=0.06) but was not associated with systolic or diastolic BP (p>0.05). To our knowledge there are no other studies pub- lished on this polymorphism and stroke.J. Jannes, M.A. Hamilton-Bruce, A. Milton, S.A. Kobla
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