Stony Brook University

About: Stony Brook University is a education organization based out in Stony Brook, New York, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 32534 authors who have published 68218 publications receiving 3035131 citations. The organization is also known as: State University of New York at Stony Brook & SUNY Stony Brook.

Calculating the Jet Quenching Parameter

Abstract: Models of medium-induced radiative parton energy loss account for the strong suppression of high-p{sub T} hadron spectra in {radical}(s{sub NN})=200 GeV Au-Au collisions at BNL RHIC in terms of a single 'jet quenching parameter' q-circumflex. We observe that q-circumflex can be given a model-independent, nonperturbative, quantum field theoretic definition in terms of the short-distance behavior of a particular lightlike Wilson loop. We then use the anti-de Sitter/conformal-field-theory correspondence to obtain a strong-coupling calculation of q-circumflex in hot N=4 supersymmetric QCD, finding q-circumflex{sub SYM}=26.69{radical}({alpha}{sub SYM}N{sub c})T{sup 3} in the limit in which both N{sub c} and 4{pi}{alpha}{sub SYM}N{sub c} are large. Thus, at strong coupling q-circumflex is not proportional to the entropy density s, or to some ''number density of scatterers'' since, unlike the number of degrees of freedom, q-circumflex does not grow like N{sub c}{sup 2}.

Interleukin 1 regulates synthesis of amyloid beta-protein precursor mRNA in human endothelial cells.

Abstract: We have analyzed the modulation of amyloid beta-protein precursor (APP) gene expression in human umbilical vein endothelial cells (HUVEC). The level of the APP mRNA transcripts increased as HUVEC reached confluency. In confluent culture the half-life of the APP mRNA was 4 hr. Treatment of the cells with human-recombinant interleukin 1 (IL-1), phorbol 12-myristate 13-acetate, or heparin-binding growth factor 1 enhanced the expression of APP gene in these cells, but calcium ionophore A23187 and dexamethasone did not. The protein kinase C inhibitor 1-(isoquinolinsulfonyl)-2-methylpiperazine (H7) inhibited IL-1-mediated increase of the level of APP transcripts. To map IL-1-responsive elements of the APP promoter, truncated portions of the APP promoter were fused to the human growth hormone reporter gene. The recombinant plasmids were transfected into mouse neuroblastoma cells, and the cell medium was assayed for the human growth hormone. A 180-base-pair region of the APP promoter located between position -485 and -305 upstream from the transcription start site was necessary for IL-1-mediated induction of the reporter gene. This region contains the upstream transcription factor AP-1 binding site. These results suggest that IL-1 upregulates APP gene expression in HUVEC through a pathway mediated by protein kinase C, utilizing the upstream AP-1 binding site of the APP promoter.

Removal of interstitial H2O in hexacyanometallates for a superior cathode of a sodium-ion battery.

Abstract: Sodium is globally available, which makes a sodium-ion rechargeable battery preferable to a lithium-ion battery for large-scale storage of electrical energy, provided a host cathode for Na can be found that provides the necessary capacity, voltage, and cycle life at the prescribed charge/discharge rate. Low-cost hexacyanometallates are promising cathodes because of their ease of synthesis and rigid open framework that enables fast Na+ insertion and extraction. Here we report an intriguing effect of interstitial H2O on the structure and electrochemical properties of sodium manganese(II) hexacyanoferrates(II) with the nominal composition Na2MnFe(CN)6·zH2O (Na2−δMnHFC). The newly discovered dehydrated Na2−δMnHFC phase exhibits superior electrochemical performance compared to other reported Na-ion cathode materials; it delivers at 3.5 V a reversible capacity of 150 mAh g–1 in a sodium half cell and 140 mAh g–1 in a full cell with a hard-carbon anode. At a charge/discharge rate of 20 C, the half-cell capacity ...