Identification and analysis of factors affecting thermal shock resistance of ceramic materials in solar receivers

An analysis was conducted of the possible modes of thermal stress failure of brittle ceramics for potential use in point-focussing solar receivers. The pertinent materials properties which control thermal stress resistance were identified for conditions of steady-state and transient heat flow, convective and radiative heat transfer, thermal buckling and thermal fatigue as well as catastrophic crack propagation. Selection rules for materials with optimum thermal stress resistance for a particular thermal environment were identified. Recommendations for materials for particular components were made. The general requirements for a thermal shock testing program quantitatively meaningful for point-focussing solar receivers were outlined. Recommendations for follow-on theoretical analyses were made

Awareness of Dentine Hypersensitivity among General Dental Practitioners in Mumbai, India.

Aim: The aim of this study was to describe the perception of dentists in general dental practice on the diagnosis and management of dentine hypersensitivity (DH) as perceived by a randomly selected sample of private dental practitioners in Mumbai. Methods: 500 dentists (Mean age 38-35 years [S.D = 11.3], 114 M: 92 F were randomly selected using the Indian Dental Association membership list and invited to participate in a questionnaire-based survey. Results: 206 private practitioners (GDPs) were included in the final analysis of the data. Most of these respondents [90.2%]) indicated that half of their patients reported problems with DH;78.2% respondents reported that the patients to usually initiated the conversation on DH; and 83.4% indicated that up to 25% of their patients considered DH as a serious problem. A greater part of the respondents (62.2%) reported that the pain due to DH lasted ≤4 weeks. There was an overall awareness regarding the current mechanisms underlying DH, with the majority of dentists (≥66%) reporting inadequate brushing of the teeth as an initiating cause and approximately 50% suggesting periodontal causes amongst the other recorded reasons. The most common management strategy employed by dentists was to prescribe desensitizing agents for home use. Conclusion: The conclusions from the present study were in agreement with the results from previous studies and generally consistent with the current scientific consensus on the management of DH by GDPs

Prevalence and Pattern of Dentine Hypersensitivity in a population of patients at MGM Dental College

Aim: The aim of this study was to determine the prevalence of Dentine Hypersensitivity (DH) in an Indian population and to assess the factors associated with this condition. Methods: 4200 subjects were examined in the Out-Patient Department (OPD) at the MGM Dental College, Navi Mumbai City. Patients who complained of dentine hypersensitivity were given the questionnaire to complete, in order to obtain the following information, demographics, dental history, eating habits and DH symptom data, and associated known factors relating to DH. In total 548 questionnaires were completed. Oral examinations assessed DH in participants who reported DH in at least one of their teeth. The subjects also quantified the severity of DH on 10-digit visual analogue scale. The diagnosis of DH was established by a short, sharp pain arising from exposed dentine in response to triple syringe air blast and explorer probe of the tooth surface. Results: The prevalence of self-reported DH was 13%; and that of clinically diagnosed DH was 8.2%. Numerically more males were examined compared to females although there were no differences in the prevalence of DH between the two groups. DH. The peak prevalence of DH was in the 30-39 years age group. Mandibular central incisors and first molars were significantly the most affected teeth. Cold (89.4%) was the most common cause of DH. Those subjects having moderate sensitivity for ≤ 6 months resorted to home remedies of brushing with a desensitizing paste to relieve the problem rather than visit their local dentist. However only 41 (8.8%) of the total participants claimed to have attended a dental practice. Conclusion: The results from the study would suggest that DH is a common prevalent dental condition in India. Although the condition appears to cause a degree of noticeable discomfort, most patients choose to either ignore the condition or simply tolerate it. Therefore, it can be assumed that the condition does not cause a significant effect on the quality of life or life style of the individual complaining of the problem

In vivo imaging of pyrrole-imidazole polyamides with positron emission tomography

The biodistribution profiles in mice of two pyrrole-imidazole polyamides were determined by PET. Pyrrole-imidazole polyamides are a class of small molecules that can be programmed to bind a broad repertoire of DNA sequences, disrupt transcription factor-DNA interfaces, and modulate gene expression pathways in cell culture experiments. The 18F-radiolabeled polyamides were prepared by oxime ligation between 4-[18F]-fluorobenzaldehyde and a hydroxylamine moiety at the polyamide C terminus. Small animal PET imaging of radiolabeled polyamides administered to mice revealed distinct differences in the biodistribution of a 5-ring β-linked polyamide versus an 8-ring hairpin, which exhibited better overall bioavailability. In vivo imaging of pyrrole-imidazole polyamides by PET is a minimum first step toward the translation of polyamide-based gene regulation from cell culture to small animal studies

X-ray structure of gelonin and gelonin-AMP complex

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An approach to verification and validation of MHD codes for fusion applications

We propose a new activity on verification and validation (V&V) of MHD codes presently employed by the fusion community as a predictive capability tool for liquid metal cooling applications, such as liquid metal blankets. The important steps in the development of MHD codes starting from the 1970s are outlined first and then basic MHD codes, which are currently in use by designers of liquid breeder blankets, are reviewed. A benchmark database of five problems has been proposed to cover a wide range of MHD flows from laminar fully developed to turbulent flows, which are of interest for fusion applications: (A) 2D fully developed laminar steady MHD flow, (B) 3D laminar, steady developing MHD flow in a non-uniform magnetic field, (C) quasi-two-dimensional MHD turbulent flow, (D) 3D turbulent MHD flow, and (E) MHD flow with heat transfer (buoyant convection). Finally, we introduce important details of the proposed activities, such as basic V&V rules and schedule. The main goal of the present paper is to help in establishing an efficient V&V framework and to initiate benchmarking among interested parties. The comparison results computed by the codes against analytical solutions and trusted experimental and numerical data as well as code-to-code comparisons will be presented and analyzed in companion paper/paper

Human carbonic anhydrase I-iodide complex: structure and inhibition mechanism

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