786 research outputs found

    Synthesis of single-component metallic glasses by thermal spray of nanodroplets on amorphous substrates

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    We show that single component metallic glasses can be synthesized by thermal spray coating of nanodroplets onto an amorphous substrate. We demonstrate this using molecular dynamics simulations of nanodroplets up to 30 nm that the spreading of the nanodroplets during impact on a substrate leads to sufficiently rapid cooling (10^(12)–10^(13) K/s) sustained by the large temperature gradients between the thinned nanodroplets and the bulk substrate. However, even under these conditions, in order to ensure that the glass transition outruns crystal nucleation, it is essential that the substrate be amorphous (eliminating sites for heterogeneous nucleation of crystallization)

    Experimental Investigation of Blast-Pressure Attenuation by Cellular Concrete

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    Results from an experimental investigation of the dynamic response of cellular concrete subjected to blast-pressure loading are presented. The cellular concrete has large entrained porosity in the form of uniformly distributed air cells in a matrix of hardened cement. Under quasi-static loading, once the applied stress exceeds the crushing strength of the cellular concrete, crushing and densification of material results in an upward concave stress-strain response. The shock-tube experimental test setup used for generating blast-pressure loading in a controlled manner is described. Experimental results from the cellular concrete subjected to blast-pressure loading with pressure amplitude greater than its crushing strength indicate that a compression stress wave, which produces compaction of the material due to collapse of the cellular structure, is produced in the material. As the compaction front propagates in the material, there is a continuous decrease in its amplitude. The impulse of the blast pressure wave is conserved. When a sufficient length of the cellular concrete is present, the applied blast pressure wave is completely attenuated to a rectangular stress pulse. The transmitted stress to a substrate from cellular concrete when an applied blast pressure wave is completely attenuated resembles a rectangular stress pulse of amplitude slightly higher than the crushing strength of the material with a duration predicted by the applied blast impulse

    Suppression of high pTp_T hadron spectra in p+Ap+A collisions

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    Multiple hard and semi-hard parton scatterings in high-energy p+Ap+A collisions involve multi-parton correlation in both momentum and flavor inside the projectile proton which will lead to modification of the final hadron spectra relative to that in p+pp+p collisions. Such modification of final hadron transverse momentum spectra in p+Ap+A collisions is studied within HIJING 2.1 Monte Carlo model which includes nuclear shadowing of the initial parton distributions and transverse momentum broadening. Multi-parton flavor and momentum correlation inside the projectile are incorporated through flavor and momentum conservation which are shown to modify the flavor content and momentum spectra of final partons and most importantly lead to suppression of large pTp_{T} hadron spectra in p+Ap+A collisions at both RHIC and LHC energies.Comment: 4 pages, 3 figures, talk given at the 5th international conference on Hard and Electromagnetic Probes of High Energy nuclear Collisions (Hard Probes 2012

    HDAC8 and STAT3 Repress BMF Gene Activity in Colon Cancer Cells

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    Histone deacetylase (HDAC) inhibitors are undergoing clinical trials as anticancer agents, but some exhibit resistance mechanisms linked to anti-apoptotic Bcl-2 functions, such as BH3-only protein silencing. HDAC inhibitors that reactivate BH3-only family members might offer an improved therapeutic approach. We show here that a novel seleno-α-keto acid triggers global histone acetylation in human colon cancer cells and activates apoptosis in a p21-independent manner. Profiling of multiple survival factors identified a critical role for the BH3-only member Bcl-2-modifying factor (Bmf). On the corresponding BMF gene promoter, loss of HDAC8 was associated with signal transducer and activator of transcription 3 (STAT3)/specificity protein 3 (Sp3) transcription factor exchange and recruitment of p300. Treatment with a p300 inhibitor or transient overexpression of exogenous HDAC8 interfered with BMF induction, whereas RNAi-mediated silencing of STAT3 activated the target gene. This is the first report to identify a direct target gene of HDAC8 repression, namely, BMF. Interestingly, the repressive role of HDAC8 could be uncoupled from HDAC1 to trigger Bmf-mediated apoptosis. These findings have implications for the development of HDAC8-selective inhibitors as therapeutic agents, beyond the reported involvement of HDAC8 in childhood malignancy

    PENGEMBANGAN ENERGI TERBARUKAN MELALUI EVALUASI PROGRAM KONVERSI MINYAK TANAH KE LPG DI PULAU GILI RAJA-SUMENEP (Developing Renewable Energy Through An Evaluation for A Program of Kerosene Conversion to LPG in Gili Raja Island - Sumenep)

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    ABSTRAKPenelitian ini mengevaluasi program konversi minyak tanah ke Liquefied Petroleum Gas (LPG) pada kelompok sasaran di pulau Gili Raja kabupaten Sumenep Jawa Timur. Kajian sebelumnya terhadap program ini masih bersifat formatif dengan fokus efisiensi dan efektivitas implementasi. Dengan menggunakan metode Minimum Evaluation Procedure (MEP) penelitian ini mempertanyakan implementasi program secara runtut, mulai output, outcome sampai impact. Melalui pendekatan kualitatif penelitian ini dapat mendeskripsikan konteks dan setting secara alamiah. Hasil penelitian menunjukkan adanya pungutan dalam proses distribusi paket program, rendahnya akses atau penggunaan paket program serta tidak adanya dampak program. Selain itu, ditemukan adanya potensi lokal berupa kotoran ternak yang dapat dikembangkan menjadi sumber daya energi terbarukan. Berdasarkan hal itu, disarankan sebuah program dapat dikembangkan secara asimetris sesuai dengan kondisi lokasi dan kelompok sasaran, terjadinya komunikasi intensif antara pelaksana program dengan kelompok sasaran serta stakeholders lainnya. Berdasarkan potensi kelompok sasaran di pulau Gili Raja, hendaknya dikembangkan kebijakan energi alternatif biogas untuk memenuhi kebutuhan energi masyarakat serta mendukung pencapaian tujuan kebijakan energi nasional. ABSTRACTThe purpose of this research is to evaluate the conversion programfrom kerosene to Liquefied Petroleum Gas (LPG) on a target group in Gili Raja island of SumenepMunicipal, East Java. Previous study on this program was quite formative one and focusing on the efficiency and the effectiveness of the program implementation. In addition, by applying Minimum Evaluation Procedure’s (MEP) method, this research questioned the implementation of the program consecutively from the output, the outcome as well as the impact. Furthermore, through a qualitative approach, this research will be able to describe context and setting naturally. Result of the research shows that there is illegal fees (levies) in the process of distributing the program package, also the limited access or the low utilization of the program package, as well as the non-existing evidence of the program’s impact. Furthermore, it is found a local potential in the form of renewable energy that is generated from livestock’s feces. Hence, it is recommended to establish a program, asymmetrically, in accordance with the local condition and the target group that ensures the occurrence of an intensive communication amongst program implementer, target group, and other stakeholders. Moreover, based on the potency of the target group of Gili Raja, an alternative policy on renewable energy should be developed in order to fulfill the need of energy for Gili Raja’s people, as well as to support the achievement of the National energy policy

    E2F1 Suppresses Oxidative Metabolism and Endothelial Differentiation of Bone Marrow Progenitor Cells

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    RATIONALE: The majority of current cardiovascular cell therapy trials use bone marrow progenitor cells (BM PCs) and achieve only modest efficacy; the limited potential of these cells to differentiate into endothelial-lineage cells is one of the major barriers to the success of this promising therapy. We have previously reported that the E2F transcription factor 1 (E2F1) is a repressor of revascularization after ischemic injury. OBJECTIVE: We sought to define the role of E2F1 in the regulation of BM PC function. METHODS AND RESULTS: Ablation of E2F1 (E2F1 deficient) in mouse BM PCs increases oxidative metabolism and reduces lactate production, resulting in enhanced endothelial differentiation. The metabolic switch in E2F1-deficient BM PCs is mediated by a reduction in the expression of pyruvate dehydrogenase kinase 4 and pyruvate dehydrogenase kinase 2; overexpression of pyruvate dehydrogenase kinase 4 reverses the enhancement of oxidative metabolism and endothelial differentiation. Deletion of E2F1 in the BM increases the amount of PC-derived endothelial cells in the ischemic myocardium, enhances vascular growth, reduces infarct size, and improves cardiac function after myocardial infarction. CONCLUSION: Our results suggest a novel mechanism by which E2F1 mediates the metabolic control of BM PC differentiation, and strategies that inhibit E2F1 or enhance oxidative metabolism in BM PCs may improve the effectiveness of cell therapy

    The electronic structure of amorphous silica: A numerical study

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    We present a computational study of the electronic properties of amorphous SiO2. The ionic configurations used are the ones generated by an earlier molecular dynamics simulations in which the system was cooled with different cooling rates from the liquid state to a glass, thus giving access to glass-like configurations with different degrees of disorder [Phys. Rev. B 54, 15808 (1996)]. The electronic structure is described by a tight-binding Hamiltonian. We study the influence of the degree of disorder on the density of states, the localization properties, the optical absorption, the nature of defects within the mobility gap, and on the fluctuations of the Madelung potential, where the disorder manifests itself most prominently. The experimentally observed mismatch between a photoconductivity threshold of 9 eV and the onset of the optical absorption around 7 eV is interpreted by the picture of eigenstates localized by potential energy fluctuations in a mobility gap of approximately 9 eV and a density of states that exhibits valence and conduction band tails which are, even in the absence of defects, deeply located within the former band gap.Comment: 21 pages of Latex, 5 eps figure

    Calculating Dilepton Rates from Monte Carlo Simulations of Parton Production

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    To calculate dilepton rates in a Monte Carlo simulation of ultrarelativistic heavy ion collisions, one usually scales the number of similar QCD processes by a ratio of the corresponding differential probabilities. We derive the formula for such a ratio especially for dilepton bremsstrahlung processes. We also discuss the non-triviality of including higher order corrections to direct Drell-Yan process. The resultant mass spectra from our Monte Carlo simulation are consistent with the semi-analytical calculation using dilepton fragmentation functions.Comment: 14 pages in RevTex, 3 figures in uuencoded files, LBL-3466

    Pengaruh Pembelajaran Problem Based Learning (PBL) Terhadap Kemampuan Representasi Matematis Siswa Di Kelas VIII Yayasan Perguruan Islam SMP Cerdasmurni Tembung

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    Compositions and methods for inhibiting and/or sensitizing or re-sensitizing a parasite to an antiparasitic drug are provided. The compositions can comprise a rifamycin derivative or a pharmaceutically acceptable salt, hydrate, or prodrug thereof in an amount and formulation sufficient to inhibit or induce drug-sensitization in a parasite. The methods can comprise administering a rifamycin derivative or a pharmaceutically acceptable salt, hydrate, or prodrug thereof to a parasite in an amount and formulation sufficient to inhibit or induce drug-sensitization in the parasite.U

    Estimating Mass of Sigma-Meson and Study on Application of the Linear Sigma-Model

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    Whether the σmeson\sigma-meson (f0(600)f_0(600)) exists as a real particle is a long-standing problem in both particle physics and nuclear physics. In this work, we analyze the deuteron binding energy in the linear σ\sigma model and by fitting the data, we are able to determine the range of mσm_{\sigma} and also investigate applicability of the linear σ\sigma model for the interaction between hadrons in the energy region of MeV's. Our result shows that the best fit to the data of the deuteron binding energy and other experimental data about deuteron advocates a narrow range for the σ\sigma-meson mass as 520mσ580520\leq m_{\sigma}\leq 580 MeV and the concrete values depend on the input parameters such as the couplings. Inversely fitting the experimental data, our results set constraints on the couplings. The other relevant phenomenological parameters in the model are simultaneously obtained.Comment: 12 page
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