513 research outputs found

    The synthesis and biodistribution of 3‐(4′‐[ 125 I]‐iodophenyl)‐4‐aminobutyric acid, a radioiodinated analogue of baclofen

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    Baclofen has been found to bind to receptors in the central nervous system that are specific for γ‐aminobutyric acid (GABA), a well known inhibitory neurotransmitter. This paper describes the synthesis of a radioiodinated analog of baclofen as part of an effort to develop receptor probes useful in single photon emission computed tomography. Preliminary biodistribution studies showed the radioiodinationed analog to be essentially stable to in vivo deiodination and have a distribution profile similar to that of baclofen.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90073/1/2580280202_ftp.pd

    Murine terminal deoxynucleotidyl transferase: cellular distribution and response to cortisone

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    The mouse thymus contains two forms of terminal deoxynucleotidyl transferase (TdT) which are distinguishable by the salt concentration necessary to elute them from a phosphocellulose column, by their distrubtion among the thymocyte subpopulations, and by their sensitivity to cortisone treatment. In the whole thymus the later eluting peak (peak II) is the predominant one with about 3-10% of the total activity appearing in peak I. Both peak I and peak II activities are most sensitively assayed by the polymerization of dGMP onto an oligo(dA) primer. The minor population of thymocytes which is less dense and cortisone-resistant contains a higher specific activity of peak I TdT. The majority of TdT activity is, however, found in the major population of thymocytes which occurs in the center region of a bovine serum albumin gradient and is cortisone-sensitive. A very low level of an activity indistinguishable from peak II TdT activity is also detected in the mouse bone marrow. Other tissues, such as spleen, liver, heart, and brain lack detectable amounts of TdT activity

    Systolic and Hyper-Systolic Algorithms for the Gravitational N-Body Problem, with an Application to Brownian Motion

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    A systolic algorithm rhythmically computes and passes data through a network of processors. We investigate the performance of systolic algorithms for implementing the gravitational N-body problem on distributed-memory computers. Systolic algorithms minimize memory requirements by distributing the particles between processors. We show that the performance of systolic routines can be greatly enhanced by the use of non-blocking communication, which allows particle coordinates to be communicated at the same time that force calculations are being carried out. Hyper-systolic algorithms reduce the communication complexity at the expense of increased memory demands. As an example of an application requiring large N, we use the systolic algorithm to carry out direct-summation simulations using 10^6 particles of the Brownian motion of the supermassive black hole at the center of the Milky Way galaxy. We predict a 3D random velocity of 0.4 km/s for the black hole.Comment: 33 pages, 10 postscript figure

    Preoperative treatment with 5α-reductase inhibitors and the risk of hemorrhagic events in patients undergoing transurethral resection of the prostate – A population-based cohort study

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    OBJECTIVES: To assess the associations between preoperative treatment with 5-alpha reductase inhibitors and the risks of blood transfusion during transurethral resection of the prostate and blood clot evacuation or emergency department visits for hematuria within 1 month after surgery. METHODS: We used data from the Taiwan National Health Insurance Research Database in this population-based cohort study. A total of 3,126 patients who underwent first-time transurethral resection of the prostate from 2004 to 2013 were identified. Adjusted odds ratios estimated by multiple logistic regression models were used to assess the independent effects of the preoperative use of 5-alpha reductase inhibitors on the risks of perioperative hemorrhagic events after adjustment for potential confounders. RESULTS: Two hundred and ninety-seven (9.4%) patients were treated with 5-alpha reductase inhibitors fo

    ROR-γ drives androgen receptor expression and represents a therapeutic target in castration-resistant prostate cancer.

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    The androgen receptor (AR) is overexpressed and hyperactivated in human castration-resistant prostate cancer (CRPC). However, the determinants of AR overexpression in CRPC are poorly defined. Here we show that retinoic acid receptor-related orphan receptor γ (ROR-γ) is overexpressed and amplified in metastatic CRPC tumors, and that ROR-γ drives AR expression in the tumors. ROR-γ recruits nuclear receptor coactivator 1 and 3 (NCOA1 and NCOA3, also known as SRC-1 and SRC-3) to an AR-ROR response element (RORE) to stimulate AR gene transcription. ROR-γ antagonists suppress the expression of both AR and its variant AR-V7 in prostate cancer (PCa) cell lines and tumors. ROR-γ antagonists also markedly diminish genome-wide AR binding, H3K27ac abundance and expression of the AR target gene network. Finally, ROR-γ antagonists suppressed tumor growth in multiple AR-expressing, but not AR-negative, xenograft PCa models, and they effectively sensitized CRPC tumors to enzalutamide, without overt toxicity, in mice. Taken together, these results establish ROR-γ as a key player in CRPC by acting upstream of AR and as a potential therapeutic target for advanced PCa

    Prism-Based Sunlight Concentrator Layout: A Genetic Algorithm Solution

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    Solar energy is a promising source of energy because it is abundant and harmless to the environment. One of the critical issues involving solar energy is the layout design of sunlight concentrators. This study presents a computational method for reforming the layout of a special sunlight concentrator that consists of a set of prisms to significantly enhance its light intensity. Sunlight movement toward the prisms is modeled, and a genetic algorithm is applied to find a good concentrator layout. Experiments under various light transmission rates validate the performance of our proposed method. The proposed optimal sunlight concentrator layout improves the intensity of light by 55%

    2-(5,6-Dihydro­benzimidazo[1,2-c]quinazolin-6-yl)-5-meth­oxy­phenol

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    In the title quinazoline derivative, C21H17N3O2, the benzimidazole unit makes dihedral angles of 8.29 (5) and 81.79 (5)° with the benzene rings of the quinazoline and meth­oxy­phenol units, respectively. The nitro­gen-containing six-membered ring adopts a half-chair conformation. In the crystal, the mol­ecules are linked through O—H⋯N hydrogen bonds into screw chains along the b axis; adjacent chains are further connected by N—H⋯O hydrogen bonds, thereby forming a two-dimensional network lying parallel to the bc plane. Weak C—H⋯π and π⋯π inter­actions with centroid–centroid distances of 3.5258 (8) and 3.7184 (7) Å are present and N⋯O [2.6816 (15) and 3.0519 (15) Å] short contacts also occur

    Energy Conditions in f(G)f(G) Modified Gravity with Non-minimal Coupling to Matter

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    In this paper we study a model of modified gravity with non-minimal coupling between a general function of the Gauss-Bonnet invariant, f(G)f(G), and matter Lagrangian from the point of view of the energy conditions. Such model has been introduced in Ref. [21] for description of early inflation and late-time cosmic acceleration. We present the suitable energy conditions for the above mentioned model and then, we use the estimated values of the Hubble, deceleration and jerk parameters to apply the obtained energy conditions to the specific class of modified Gauss-Bonnet models.Comment: 12 pages, no figur, Accepted for publication in Astrophysics and Space Scienc
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