11,765 research outputs found

    The magnitude of the non-adiabatic pressure in the cosmic fluid

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    Understanding the non-adiabatic pressure, or relative entropy, perturbation is crucial for studies of early-universe vorticity and Cosmic Microwave Background observations. We calculate the evolution of the linear non-adiabatic pressure perturbation from radiation domination to late times, numerically solving the linear governing equations for a wide range of wavenumbers. Using adiabatic initial conditions consistent with WMAP seven year data, we find nevertheless that the non-adiabatic pressure perturbation is non-zero and grows at early times, peaking around the epoch of matter/radiation equality and decaying in matter domination. At early times or large redshifts (z=10,000) its power spectrum peaks at a comoving wavenumber k~0.2h/Mpc, while at late times (z=500) it peaks at k~0.02 h/Mpc.Comment: 5 pages, 4 figures. Replaced with version accepted by MNRAS. One figure removed, added some discussio

    The androgen receptor and signal-transduction pathways in hormone-refractory prostate cancer. Part 1: modifications to the androgen receptor

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    Prostate cancer is the second most common male malignancy in the western world an increasing incidence in an ageing population. Treatment of advanced prostate cancer relies on androgen deprivation. Although the majority of patients initially respond favourably to androgen deprivation therapy, the mean time to relapse is 12-18 months. Currently there are few treatments available for men who have developed resistance to hormone therapy, due to the lack of understanding of the molecular mechanisms underlying development of this disease. Recently, however, major advances have been made in understanding both androgen receptor (AR) dependent and independent pathways which promote development of hormone resistant prostate cancer. This review will focus on modifications to the AR and associated pathways. Molecular modifications to the androgen receptor itself, e.g. mutations and/or amplification, although involved in the development of hormone resistance cannot explain all cases. Phosphorylation of AR, via either Ras/MAP kinase or PI3K/Akt signal transduction pathways, have been shown to activate AR in both a ligand (androgen) dependent and independent fashion. During this review we will discuss the clinical evidence to support AR dependent pathways as mediators of hormone resistance

    Determination of genetic variability of Asian rice (Oryza sativa L.) varieties using microsatellite markers

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    The microsatellite or simple sequence repeat (SSR) marker analysis was done to determine the allelic diversity and relationship among thirty-five Asian cultivars of rice including 19 aromatic, 13 nonaromaticand 3 japonica type cultivars. A total of 144 alleles were detected at the 32 SSR loci, of which 141 (98%) were polymorphic. The number of alleles generated by each marker ranged from 2 to 13 with an average of 4.5 alleles per marker. The size of smallest and largest allele ranged from 8(RM122) to as high as 71 (RM302). Polymorphism information content (PIC) values ranged between 0.157 (RM19, RM55) and 0.897 (RM70), with an average of 0.603 per marker. Basmati rice varieties amplified different alleles at 15 of the SSR loci than those in the japonica and/ or indica rice varieties. A number of SSRs were identified that could be utilized to differentiate between basmati and other non-basmati rice varieties. The RM252 and RM310 showed a clear differentiation of japonica cultivarsfrom other ones. Pair-wise Nei and Li’s similarity coefficients ranged from 0.19 to 0.90. The dendrogram based on the cluster analysis by microsatellite polymorphism, grouped 35 rice cultivars into two major groups effectively differentiating the tall, late maturing and slender aromatic cultivars from the short statured, early, short bold and long bold non-aromatic cultivars. These results could be useful for monitoring purity, genotype identification and for plant variety protection

    Electronic Tuning of Zinc Oxide by Direct Fabrication of Chromium (Cr) incorporated photoanodes for Visible-light driven Water Splitting Applications

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    This is the final version. Available on open access from Nature Research via the DOI in this recordHerein, we report the synthesis of Cr incorporated ZnO sheets arrays microstructures and construction of photoelectrode through a direct aerosol assisted chemical vapour deposition (AACVD) method. The as-prepared Cr incorporated ZnO microstructures were characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, powdered X-ray spectroscopy, X-ray photoelectron spectroscopy and UV-Vis diffused reflectance spectroscopy. The Cr incorporation in ZnO red shifted the optical band gap of as-prepared photoanodes. The 15% Cr incorporation in ZnO has shown enhanced PEC performance. The AACVD method provides an efficient in situ incorporation approach for the manipulation of morphological aspects, phase purity, and band structure of photoelectrodes for an enhanced PEC performance.Higher Education Commission of PakistanUniversity of Mancheste

    A novel CYP1A1 gene polymorphism and the risk of head and neck cancer in Pakistani population

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    Several polymorphisms in the CYP1A1 locus have been identified and their genotypes appear to exhibit population frequencies that depend on ethnicity. In this study, we assessed the role of CYP1A1 genotype in 388 head and neck cancer patients in Pakistani population via a case-control study. Polymerase chain reaction (PCR) and single stranded conformational polymorphism assays were used. Most of the patients (51%) enrolled for the study, were from the age group of 40 to 60 years (±16.59). Mean age of the cancer patients involved in the study was 48 ± 16.59 years. Statistical analysis has shown that, tobacco users have more chances of head and neck cancer (P < 0.05) than non tobacco users, whereas male to female ratio is 1:1 (P > 0.05). Jobless persons are more prone to head and neck cancer (P < 0.01) compared with employers and housewives. After the genetic analysis, it was found that no already reported variants of CYP1A1 gene were found in Pakistani population. A novel mutation in CYP1A1 gene at exon 2 in 21 patients (P < 0.001, Odd Ratio (OR) = 9.4 and 95% confidence interval (CI) 1.3 to 70.8) has been found with a serine formation instead of tyrosine at amino acid 110. The patients showing this mutation have the mean age of 51.75 (±15.7). Therefore, mutation in CYP1A1 gene may be one of several factors that increase the chance of developing head and neck cancer.Key words: Cytochrome P450 1A1 gene (CYP1A1), head and neck cancer (HNC), mutation, novel polymorphism, Pakistani population

    In-Hand Object Rotation via Rapid Motor Adaptation

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    Generalized in-hand manipulation has long been an unsolved challenge of robotics. As a small step towards this grand goal, we demonstrate how to design and learn a simple adaptive controller to achieve in-hand object rotation using only fingertips. The controller is trained entirely in simulation on only cylindrical objects, which then - without any fine-tuning - can be directly deployed to a real robot hand to rotate dozens of objects with diverse sizes, shapes, and weights over the z-axis. This is achieved via rapid online adaptation of the controller to the object properties using only proprioception history. Furthermore, natural and stable finger gaits automatically emerge from training the control policy via reinforcement learning. Code and more videos are available at https://haozhi.io/horaComment: CoRL 2022. Code and Website: https://haozhi.io/hor
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