25,491 research outputs found

    Scotin, a novel p53-inducible proapoptotic protein located in the ER and the nuclear membrane

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    p53 is a transcription factor that induces growth arrest or apoptosis in response to cellular stress. To identify new p53-inducible proapoptotic genes, we compared, by differential display, the expression of genes in spleen or thymus of normal and p53 nullizygote mice after γ-irradiation of whole animals. We report the identification and characterization of human and mouse Scotin homologues, a novel gene directly transactivated by p53. The Scotin protein is localized to the ER and the nuclear membrane. Scotin can induce apoptosis in a caspase-dependent manner. Inhibition of endogenous Scotin expression increases resistance to p53-dependent apoptosis induced by DNA damage, suggesting that Scotin plays a role in p53-dependent apoptosis. The discovery of Scotin brings to light a role of the ER in p53-dependent apoptosis

    Mott g-Ratios in Rbx(NH3)1-x and Oxidation state of Rubidium Compounds from XAS

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    The x-ray absorption spectra (XAS) of Rb metal, Rh,( JH,J, ,, 2H-NbSe2Rb111x and RbBr near the Rb K-edge have been used to ascertain that the oxidation state V of rubidium dissolved in ammonia and intt:rcalated in the layer compound is in the range 0 \u3c V \u3c I. Theobservededge shifts with temperature for semimctals are explainedin terms of the population of band states, and the ratio of the density states near the mobility edge over that calculated for a free electron model, i.e. the Mott ratio g, is ascertained using a semiempirical relation developed for the x-ray absorbance from Is levels to empty states ncar the mobility edge

    Estimation of Seismic Compression in Dry Soils Using the CPT

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    A popular method to evaluate earthquake induced settlements in dry sands is the approach proposed by Pradel (1998) which was based on standard penetration test (SPT) results and is only applicable to clean sands. A simple modification of the Pradel (1998) method is proposed based on cone penetration test (CPT) results and is extended to cover a wide range of unsaturated soils. A key parameter in the method by Pradel (1998) is the small strain shear modulus, Go, which can be estimated from the CPT or measured using the seismic CPT. The CPT can provide a continuous evaluation of seismic compression that allows the expeditious analysis of complicated soil profiles and a framework for sensitivity analyses. Soil parameters, such as soil type, fines content, and equivalent SPT blow count interpolated from CPTs, were compared with adjacent borings and related laboratory test results from a ground improvement site. Both vibro-stone columns and compaction grouting were adopted to mitigate the site seismic settlement. The proposed simple modification of the Pradel method provided a valuable tool to evaluate the effectiveness of ground improvement work

    Transport theory yields renormalization group equations

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    We show that dissipative transport and renormalization can be described in a single theoretical framework. The appropriate mathematical tool is the Nakajima-Zwanzig projection technique. We illustrate our result in the case of interacting quantum gases, where we use the Nakajima-Zwanzig approach to investigate the renormalization group flow of the effective two-body interaction.Comment: 11 pages REVTeX, twocolumn, no figures; revised version with additional examples, to appear in Phys. Rev.

    A possible mechanism of ultrafast amorphization in phase-change memory alloys: an ion slingshot from the crystalline to amorphous position

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    We propose that the driving force of an ultrafast crystalline-to-amorphous transition in phase-change memory alloys are strained bonds existing in the (metastable) crystalline phase. For the prototypical example of GST, we demonstrate that upon breaking of long Ge-Te bond by photoexcitation Ge ion shot from an octahedral crystalline to a tetrahedral amorphous position by the uncompensated force of strained short bonds. Subsequent lattice relaxation stabilizes the tetrahedral surroundings of the Ge atoms and ensures the long-term stability of the optically induced phase.Comment: 6 pages, 3 figure

    Could health information systems enhance the quality of Aboriginal health promotion? A retrospective audit of Aboriginal health programs in the Northern Territory of Australia.

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    BACKGROUND:In Australia, health services are seeking innovative ways to utilize data stored in health information systems to report on, and improve, health care quality and health system performance for Aboriginal Australians. However, there is little research about the use of health information systems in the context of Aboriginal health promotion. In 2008, the Northern Territory's publicly funded healthcare system introduced the quality improvement program planning system (QIPPS) as the centralized online system for recording information about health promotion programs. The purpose of this study was to explore the potential for utilizing data stored in QIPPS to report on quality of Aboriginal health promotion, using chronic disease prevention programs as exemplars. We identify the potential benefits and limitations of health information systems for enhancing Aboriginal health promotion. METHODS:A retrospective audit was undertaken on a sample of health promotion projects delivered between 2013 and 2016. A validated, paper-based audit tool was used to extract information stored in the QIPPS online system and report on Aboriginal health promotion quality. Simple frequency counts were calculated for dichotomous and categorical items. Text was extracted and thematically analyzed to describe community participation processes and strategies used in Aboriginal health promotion. RESULTS:39 Aboriginal health promotion projects were included in the analysis. 34/39 projects recorded information pertaining to the health promotion planning phases, such as statements of project goals, 'needs assessment' findings, and processes for consulting Aboriginal people in the community. Evaluation findings were reported in approximately one third of projects and mostly limited to a recording of numbers of participants. For almost half of the projects analyzed, community participation strategies were not recorded. CONCLUSION:This is the first Australian study to shed light on the feasibility of utilizing data stored in a purposefully designed health promotion information system. Data availability and quality were limiting factors for reporting on Aboriginal health promotion quality. Based on our learnings of QIPPS, strategies to improve the quality and accuracy of data entry together with the use of quality improvement approaches are needed to reap the potential benefits of future health promotion information systems

    Studies in synthetic carbonatite systems: Solidus relationships for CaO-MgO-CO_2-H_2O to 40 kbar and CaO-MgO-SiO_2-CO_2-H_2O to 10 kbar

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    The system CaO-MgO-SiO_2-CO_2-H_2O is an important model for many igneous and metamorphic processes, including the generation and differentiation of carbonatite and associated silicate magmas. We have experimentally established the vapor-saturated solidus for the system CaO-MgO-CO_2-H_2O from 595°C/1 kbar to <500°C/40 kbar, about 25°C lower than the corresponding temperatures for the CaO-CO_2-H_2O system. Brucite replaces periclase on the vapor-saturated solidus at about 750 bars pressure, remaining as the stable phase to pressures of at least 40 kbar; no dolomite or magnesite was encountered. At a pressure between 35 and 40 kbar, the assemblage portlandite + brucite + aragonite + vapor changes to one containing phase W, a previously unreported Ca-Mg carbonate. At 20 kbar, the vapor-saturated liquid contains at least 24 wt % H_2O. The vapor-saturated solidus for the system CaO-MgO-SiO_2-CO_2-H_2O ranges from 613°C/1 kbar to 565°C/10 kbar, experimentally indistinguishable from that for CaO-MgO-CO_2-H_2O, about 10°C lower than that for CaO-CO_2-H_2O, and about 25°C lower than that for CaO-SiO_2-CO_2-H_2O. In the quinary system, monticellite is replaced by dellaite and an unidentified silicate on the vapor-saturated solidus above 4.1 kbar. MgO-poor liquids are similar in composition to the magma from which the Magnet Cove calcite carbonatite crystallized. More magnesian magmas would produce dolomite at moderate depths, such as at Alnö Island

    Making Sense of the Legendre Transform

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    The Legendre transform is an important tool in theoretical physics, playing a critical role in classical mechanics, statistical mechanics, and thermodynamics. Yet, in typical undergraduate or graduate courses, the power of motivation and elegance of the method are often missing, unlike the treatments frequently enjoyed by Fourier transforms. We review and modify the presentation of Legendre transforms in a way that explicates the formal mathematics, resulting in manifestly symmetric equations, thereby clarifying the structure of the transform algebraically and geometrically. Then we bring in the physics to motivate the transform as a way of choosing independent variables that are more easily controlled. We demonstrate how the Legendre transform arises naturally from statistical mechanics and show how the use of dimensionless thermodynamic potentials leads to more natural and symmetric relations.Comment: 11 pages, 3 figure
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