55 research outputs found
Facet modulation selective epitaxy–a technique for quantum-well wire doublet fabrication
The technique of facet modulation selective epitaxy and its application to quantum-well wire doublet fabrication are described. Successful fabrication of wire doublets in the AlxGa1–xAs material system is achieved. The smallest wire fabricated has a crescent cross section less than 140 Å thick and less than 1400 Å wide. Backscattered electron images, transmission electron micrographs, cathodoluminescence spectra, and spectrally resolved cathodoluminescence images of the wire doublets are presented
Distortion of surfactant lamellar phases with particles and rough interfaces
Even simple liquid crystal phases of surfactants display a rich variety of behavior and the understanding of the physical principles of factors that cause changes is important. It has been suggested recently that defects in liquid crystals can be important in respect of biological function of cells1. Inserting large colloidal particles even at low concentrations is known to perturb strongly the lamellar phases of non-ionic surfactants2. Our recent work has explored the difference between small perturbations of the order of the lamellar spacing and larger distortions that may primarily change the curvature and geometry by comparing effects of different size particles and by observing the modifications due to roughness in the proximity of solid/liquid interfaces. The interplay of thermal fluctuations as described by Helfrich3 that stabilize these phases and the perturbations is significant. For example both the spacing and orientation are modified with temperature and roughness near an interface. Studies of bulk and near surface behavior will be reported and discussed in terms of theoretical ideas.
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Surface acoustic wave/silicon monolithic sensor/processor
A new technique for sputter deposition of piezoelectric zinc oxide (ZnO) is described. An argon-ion milling system was converted to sputter zinc oxide films in an oxygen atmosphere using a pure zinc oxide target. Piezoelectric films were grown on silicon dioxide and silicon dioxide overlayed with gold. The sputtered films were evaluated using surface acoustic wave measurements, X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy, and resistivity measurements. The effect of the sputtering conditions on the film quality and the result of post-deposition annealing are discussed. The application of these films to the generation of surface acoustic waves is also discussed
Analysis of implications of organ donation on living donors in southeastern Iran: A qualitative study
Objectives: despite the annual increase in living donors and the positive and negative implications following organ donation, this issue had become a significant challenge for donors. The present study aimed to analyze the experiences and views of living donors to organ donation implications.Material and Methods. The present study was performed using qualitative content analysis. Twenty participants were selected using the purposive sampling method; data were collected by semi-structured interviews and analyzed based on Lundman and Graneheim contractual content analysis method after implementing MAX 12.Results. Data analysis elicitated 721 codes, 20 subcategories, six main categories, and two themes, including positive and negative implications of organ donation from the viewpoint of living donors. The main categories of positive effects resulting from organ donation included the «donor’s peace of mind», «fundamental strength», and «recipient’s achievements». On the other hand, the main categories of negative implications resulting from organ donation included «donor’s physical suffering», «damaged interactions», and «abandonment».Conclusion. Increasing the number of living donors makes us consider it essential to understand the efficiency of its two-way implications on many aspects of donor and recipient. Thus, managing the negative impacts of living organ donation and strengthening its positive side emphasizes the need to increase the awareness of organ donation associations, develop health policies at higher levels, and, most importantly, improve the satisfaction of live organ donors
Factors affecting the technical efficiency of rural primary health care centers in Hamadan, Iran: data envelopment analysis and Tobit regression
Background: Studying and monitoring the efficiency of primary health care centers has a special place in the health system. Although studies have been conducted in the field of efficiency in Iran, few have focused on rural primary health care centers. In addition, previous studies have not used the child mortality rate and Behvarzes as input and output. Objective: The present study was conducted aimed to estimate the technical efficiency of rural primary health care centers and determinant factors in Hamadan using data envelopment analysis and Tobit regression. Methods: This is a Longitudinal study of rural primary health care centers in Hamadan province (2002�2016). Data Envelopment Analysis was employed to estimate technical efficiency of sampled health facilities while Panel Tobit Analysis was applied to predict factors associated with efficiency levels. The outputs were child mortality rate under 1 year of age and child mortality rate 1 year to 5 years of age. The input was Behvarzes (rural health workers). Results: The results of efficiency analysis showed that the average efficiency scores of the centers had a fluctuating trend during the period of the study, but the average performance scores generally decreased in 2016, as compared with 2002. The highest and lowest average performance scores were observed in 2003 (0.78) and 2013 (0.56), respectively. Number of physicians and rural primary healthcare centers per population had a positive statistically significant and the number of midwives and the total fertility per population had a negative statistically significant effect on efficiency. Conclusions: The findings suggest some level of wastage of health resources in primary health centers. Findings indicate a level of waste of health resources in primary health centers. Behvarz functions in providing primary care services can be considered in the reallocation and optimal use of available resources at the level of rural health centers. © 2020, The Author(s)
Assessment of Service Quality in Teaching Hospitals of Yazd University of Medical Sciences: Using Multi-criteria Decision Making Techniques
Objectives Hospitals as integrated parts of the wide-ranging health care systems have dominant focus on health care provision to meet, maintain and promote people's health needs of a community. This study aimed to assess the service quality of teaching hospitals of Yazd University of Medical Sciences using Fuzzy Analytical Hierarchy Process (FAHP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Methods A literature review and a qualitative method were used to obtain experts� viewpoints about the quality dimensions of hospital services to design a questionnaire. Then, using a self-made questionnaire, perceptions of 300 patients about the quality of delivered services were gathered. Finally, FAHP was applied to weigh each quality dimension and TOPSIS method to rank hospital wards. Results Six dimensions including responsiveness, assurance, security, tangibles, health communication and Patient orientation were identified as affecting aspects of hospital services quality among which, security and tangibles got the highest and lowest importance respectively (0.25406, 0.06883). Findings also revealed that in hospital A, orthopedics and ophthalmology wards obtained the highest score in terms of quality while cardiology department got the lowest ranking (0.954, 0.323). In hospital B, the highest and the lowest ranking was belonged to cardiology and surgical wards (0.895, 0.00) while in hospital C, surgical units were rated higher than internal wards (0.959, 0.851). Conclusion Findings emphasized that the security dimension got the lowest ranking among SERVQUAL facets in studied hospitals. This requires hospital executives to pay special attention to the issue of patients� security and plan effectively for its promotion. © 201
The Nrf1 CNC-bZIP Protein Is Regulated by the Proteasome and Activated by Hypoxia
BACKGROUND: Nrf1 (nuclear factor-erythroid 2 p45 subunit-related factor 1) is a transcription factor mediating cellular responses to xenobiotic and pro-oxidant stress. Nrf1 regulates the transcription of many stress-related genes through the electrophile response elements (EpREs) located in their promoter regions. Despite its potential importance in human health, the mechanisms controlling Nrf1 have not been addressed fully. PRINCIPAL FINDINGS: We found that proteasomal inhibitors MG-132 and clasto-lactacystin-β-lactone stabilized the protein expression of full-length Nrf1 in both COS7 and WFF2002 cells. Concomitantly, proteasomal inhibition decreased the expression of a smaller, N-terminal Nrf1 fragment, with an approximate molecular weight of 23 kDa. The EpRE-luciferase reporter assays revealed that proteasomal inhibition markedly inhibited the Nrf1 transactivational activity. These results support earlier hypotheses that the 26 S proteasome processes Nrf1 into its active form by removing its inhibitory N-terminal domain anchoring Nrf1 to the endoplasmic reticulum. Immunoprecipitation demonstrated that Nrf1 is ubiquitinated and that proteasomal inhibition increased the degree of Nrf1 ubiquitination. Furthermore, Nrf1 protein had a half-life of approximately 5 hours in COS7 cells. In contrast, hypoxia (1% O(2)) significantly increased the luciferase reporter activity of exogenous Nrf1 protein, while decreasing the protein expression of p65, a shorter form of Nrf1, known to act as a repressor of EpRE-controlled gene expression. Finally, the protein phosphatase inhibitor okadaic acid activated Nrf1 reporter activity, while the latter was repressed by the PKC inhibitor staurosporine. CONCLUSIONS: Collectively, our data suggests that Nrf1 is controlled by several post-translational mechanisms, including ubiquitination, proteolytic processing and proteasomal-mediated degradation as well as by its phosphorylation status
Heat shock protein-90-alpha, a prolactin-STAT5 target gene identified in breast cancer cells, is involved in apoptosis regulation
Introduction The prolactin-Janus-kinase-2-signal transducer and activator of transcription-5 (JAK2-STAT5) pathway is essential for the development and functional differentiation of the mammary gland. The pathway also has important roles in mammary tumourigenesis. Prolactin regulated target genes are not yet well defined in tumour cells, and we undertook, to the best of our knowledge, the first large genetic screen of breast cancer cells treated with or without exogenous prolactin. We hypothesise that the identification of these genes should yield insights into the mechanisms by which prolactin participates in cancer formation or progression, and possibly how it regulates normal mammary gland development. Methods We used subtractive hybridisation to identify a number of prolactin-regulated genes in the human mammary carcinoma cell line SKBR3. Northern blotting analysis and luciferase assays identified the gene encoding heat shock protein 90-alpha (HSP90A) as a prolactin-JAK2-STAT5 target gene, whose function was characterised using apoptosis assays. Results We identified a number of new prolactin-regulated genes in breast cancer cells. Focusing on HSP90A, we determined that prolactin increased HSP90A mRNA in cancerous human breast SKBR3 cells and that STAT5B preferentially activated the HSP90A promoter in reporter gene assays. Both prolactin and its downstream protein effector, HSP90α, promote survival, as shown by apoptosis assays and by the addition of the HSP90 inhibitor, 17-allylamino-17-demethoxygeldanamycin (17-AAG), in both untransformed HC11 mammary epithelial cells and SKBR3 breast cancer cells. The constitutive expression of HSP90A, however, sensitised differentiated HC11 cells to starvation-induced wild-type p53-independent apoptosis. Interestingly, in SKBR3 breast cancer cells, HSP90α promoted survival in the presence of serum but appeared to have little effect during starvation. Conclusions In addition to identifying new prolactin-regulated genes in breast cancer cells, we found that prolactin-JAK2-STAT5 induces expression of the HSP90A gene, which encodes the master chaperone of cancer. This identifies one mechanism by which prolactin contributes to breast cancer. Increased expression of HSP90A in breast cancer is correlated with increased cell survival and poor prognosis and HSP90α inhibitors are being tested in clinical trials as a breast cancer treatment. Our results also indicate that HSP90α promotes survival depending on the cellular conditions and state of cellular transformation
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