1,878 research outputs found

    The Amino Terminus of the Yeast F_1-ATPase β-Subunit Precursor Functions as a Mitochondrial Import Signal

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    The ATP2 gene of Saccharomyces cerevisiae codes for the cytoplasmically synthesized beta-subunit protein of the mitochondrial F1-ATPase. To define the amino acid sequence determinants necessary for the in vivo targeting and import of this protein into mitochondria, we have constructed gene fusions between the ATP2 gene and either the Escherichia coli lacZ gene or the S. cerevisiae SUC2 gene (which codes for invertase). The ATP2-lacZ and ATP2-SUC2 gene fusions code for hybrid proteins that are efficiently targeted to yeast mitochondria in vivo. The mitochondrially associated hybrid proteins fractionate with the inner mitochondrial membrane and are resistant to proteinase digestion in the isolated organelle. Results obtained with the gene fusions and with targeting-defective ATP2 deletion mutants provide evidence that the amino-terminal 27 amino acids of the beta-subunit protein precursor are sufficient to direct both specific sorting of this protein to yeast mitochondria and its import into the organelle. Also, we have observed that certain of the mitochondrially associated Atp2-LacZ and Atp2-Suc2 hybrid proteins confer a novel respiration-defective phenotype to yeast cells

    MCViNE -- An object oriented Monte Carlo neutron ray tracing simulation package

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    MCViNE (Monte-Carlo VIrtual Neutron Experiment) is a versatile Monte Carlo (MC) neutron ray-tracing program that provides researchers with tools for performing computer modeling and simulations that mirror real neutron scattering experiments. By adopting modern software engineering practices such as using composite and visitor design patterns for representing and accessing neutron scatterers, and using recursive algorithms for multiple scattering, MCViNE is flexible enough to handle sophisticated neutron scattering problems including, for example, neutron detection by complex detector systems, and single and multiple scattering events in a variety of samples and sample environments. In addition, MCViNE can take advantage of simulation components in linear-chain-based MC ray tracing packages widely used in instrument design and optimization, as well as NumPy-based components that make prototypes useful and easy to develop. These developments have enabled us to carry out detailed simulations of neutron scattering experiments with non-trivial samples in time-of-flight inelastic instruments at the Spallation Neutron Source. Examples of such simulations for powder and single-crystal samples with various scattering kernels, including kernels for phonon and magnon scattering, are presented. With simulations that closely reproduce experimental results, scattering mechanisms can be turned on and off to determine how they contribute to the measured scattering intensities, improving our understanding of the underlying physics.Comment: 34 pages, 14 figure

    Acculturation and wellness of native american adolescents in the United States of North America

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    Cultural conflicts and the process of acculturation contribute to feelings of boredom, anxiety, depression, isolation, stress, self-doubt, alienation, and rejection among Native American high school students. Further, acculturation may have a negative impact on the identity development and wellness of these students. The purpose of this pilot study was to: (a) assess and compare the levels of acculturation of Native American and non-Native American 9th, 10th, 11th, and 12th grade students; and (b) examine the relationship between level of acculturation and wellness for the Native American students. Results indicated significant differences between Native American and non-Native American students’ levels of acculturation; and significant differences between the Native students’ three levels of acculturation on some of the 17 scales of wellness. Resumen: Conflictos culturales y el proceso de aculturación contribuyen a sentimientos de aburrimiento, ansiedad, depresión, aislamiento, presión, desconfianza, alienación, y del rechazo entre estudiantes de escuela superior que son indios americanos. Aún más, la aculturación puede tener un impacto negativo en el desarrollo de identidad y bienestar de estos estudiantes. El propósito de este estudio piloto fue: (a) evaluar y comparar los niveles de aculturación de estudiantes que eran indios americanos y no-indio americano en los grados académicos del noveno, décimo, décimo primero y de duodécimos; y (B) examinar la relación entre nivel de aculturación y bienestar de los estudiantes indio americanos. Los resultados indicaron diferencias significativas entre estudiantes indio americanos y estudiantes no-indio americano en los niveles de aculturación; y diferencias significativas entre los estudiantes indio americanos en tres niveles de aculturación en la parte de las 17 escalas del bienestar

    A game-based online tool to measure cognitive functions in students

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    Cognitive assessments can be expensive, lengthy and fatiguing for students and are often conducted in an artificial clinical context. In an effort to make the assessments more fun, researchers have started to introduce game elements to traditional cognitive tasks and training. This comes with a number of challenges. The main challenge is to develop an engaging tool that at the same time reliably assesses cognitive constructs in students. To address these challenges, this research aims to improve cognitive assessment with a new game-based assessment app that has been designed and developed in collaboration with researchers, teachers, students, and software engineers based on established cognitive theories, and subsequently validated through iterative testing in real world settings. The iterative development process is based on design-based research and includes cycles of design explorations, testing, analyses, redesign, and evaluation with students in authentic educational settings. The knowledge gained from the iterative process of designing a valid cognitive function app can inform other researchers who are aiming to develop cognitive assessment tools in an educational context

    Prostate cancer support groups: Canada-based specialists\u27 perspectives

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    To understand prostate cancer (PCa) specialists’ views about prostate cancer support groups (PCSGs), a volunteer sample of Canada-based PCa specialists ( n = 150), including urologists ( n = 100), radiation oncologists ( n = 40), and medical oncologists ( n = 10) were surveyed. The 56-item questionnaire used in this study included six sets of attitudinal items to measure prostate cancer specialists’ beliefs about positive and negative influences of PCSGs, reasons for attending PCSGs, the attributes of effective PCSGs, and the value of face-to-face and web-based PCSGs. In addition, an open-ended question was included to invite additional input from participants. Results showed that PCSGs were positively valued, particularly for information sharing, education and psychosocial support. Inclusivity, privacy, and accessibility were identified as potential barriers, and recommendations were made for better marketing PCSGs to increase engagement. Findings suggest prostate cancer specialists highly valued the role and potential benefits of face-to-face PCSGs. Information provision and an educational role were perceived as key benefits. Some concerns were expressed about the ability of web-based PCSGs to effectively engage and educate men who experience prostate cancer

    Perfect Cluster States from Imperfect Global Entanglement

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    The cluster state, the highly entangled state that is the central resource for one-way quantum computing, can be efficiently generated in a variety of physical implementations via global nearest-neighbor interactions. In practice, a systematic phase error is expected in the entangling process, resulting in imperfect cluster states. We present a stochastic measurement technique to generate large perfect cluster states and other graph states with high probability from imperfect cluster states even when their initial entanglement is weak.Comment: 16 pages IOP style, 4 EPS figures; major revisions to the strategy for growth of cluster states, 2 new figures, several new references; accepted for publication in NJ

    MicroRNA-183 Family Expression in Hair Cell Development and Requirement of MicroRNAs for Hair Cell Maintenance and Survival

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    MicroRNAs (miRNAs) post-transcriptionally repress complementary target gene expression and can contribute to cell differentiation. The coordinate expression of miRNA-183 family members (miR-183, miR-96, and miR-182) has been demonstrated in sensory cells of the mouse inner ear and other vertebrate sensory organs. To further examine hair cell miRNA expression in the mouse inner ear, we have analyzed miR-183 family expression in wild type animals and various mutants with defects in neurosensory development. miR-183 family member expression follows neurosensory cell specification, exhibits longitudinal (basal-apical) gradients in maturating cochlear hair cells, and is maintained in sensory neurons and most hair cells into adulthood. Depletion of hair cell miRNAs resulting from Dicer1 conditional knockout (CKO) in Atoh1-Cre transgenic mice leads to more disparate basal-apical gene expression profiles and eventual hair cell loss. Results suggest that hair cell miRNAs subdue cochlear gradient gene expression and are required for hair cell maintenance and survival

    An Overview of the Space Environments and Spacecraft Effects Organization Concept

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    The National Aeronautics and Space Administration (NASA) is embarking on a course to expand human presence beyond Low Earth Orbit (LEO) while also expanding its mission to explore our Earth, and the solar system. Destinations such as Near Earth Asteroids (NEA), Mars and its moons, and the outer planets are but a few of the mission targets. Each new destination presents an opportunity to increase our knowledge on the solar system and the unique environments for each mission target. NASA has multiple technical and science discipline areas specializing in specific space environments fields that will serve to enable these missions. To complement these existing discipline areas, a concept is presented focusing on the development of a space environment and spacecraft effects (SESE) organization. This SESE organization includes disciplines such as space climate, space weather, natural and induced space environments, effects on spacecraft materials and systems, and the transition of research information into application. This space environment and spacecraft effects organization will be composed of Technical Working Groups (TWG). These technical working groups will survey customers and users, generate products, and provide knowledge supporting four functional areas: design environments, engineering effects, operational support, and programmatic support. The four functional areas align with phases in the program mission lifecycle and are briefly described below. Design environments are used primarily in the mission concept and design phases of a program. Environment effects focuses on the material, component, sub-system, and system-level response to the space environment and include the selection and testing to verify design and operational performance. Operational support provides products based on real time or near real time space weather to mission operators to aid in real time and near-term decision-making. The programmatic support function maintains an interface with the numerous programs within NASA, other federal government agencies, and the commercial sector to ensure that communications are well established and the needs of the programs are being met. The programmatic support function also includes working in coordination with the program in anomaly resolution and generation of lessons learned documentation. The goal of this space environment and spacecraft effects organization is to develop decision-making tools and engineering products to support all mission phases from mission concept through operations by focusing on transitioning research to application. Products generated by this space environments and effects application are suitable for use in anomaly investigations. This paper will describe the scope and purpose of the space environments and spacecraft effects organization and describe the TWG's and their relationship to the functional areas

    360 deg Camera Head for Unmanned Sea Surface Vehicles

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    The 360 camera head consists of a set of six color cameras arranged in a circular pattern such that their overlapping fields of view give a full 360 view of the immediate surroundings. The cameras are enclosed in a watertight container along with support electronics and a power distribution system. Each camera views the world through a watertight porthole. To prevent overheating or condensation in extreme weather conditions, the watertight container is also equipped with an electrical cooling unit and a pair of internal fans for circulation

    A Mechanism Misregulating p27 in Tumors Discovered in a Functional Genomic Screen

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    The cyclin-dependent kinase inhibitor p27KIP1 is a tumor suppressor gene in mice, and loss of p27 protein is a negative prognostic indicator in human cancers. Unlike other tumor suppressors, the p27 gene is rarely mutated in tumors. Therefore misregulation of p27, rather than loss of the gene, is responsible for tumor-associated decreases in p27 protein levels. We performed a functional genomic screen in p27+/− mice to identify genes that regulate p27 during lymphomagenesis. This study demonstrated that decreased p27 expression in tumors resulted from altered transcription of the p27 gene, and the retroviral tagging strategy enabled us to pinpoint relevant transcription factors. inhibitor of DNA binding 3 (Id3) was isolated and validated as a transcriptional repressor of p27. We further demonstrated that p27 was a downstream target of Id3 in src-family kinase Lck-driven thymic lymphomagenesis and that p27 was an essential regulator of Lck-dependent thymic maturation during normal T-cell development. Thus, we have identified and characterized transcriptional repression of p27 by Id3 as a new mechanism decreasing p27 protein in tumors
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