34 research outputs found

    Surface acoustic wave/silicon monolithic sensor/processor

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    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

    The Nrf1 CNC-bZIP Protein Is Regulated by the Proteasome and Activated by Hypoxia

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    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

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    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

    Organizational Learning: The Missing Link to Promote Nurses' Professional Self-Efficacy

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    Introduction: Nurses are one of the important sources of organizational learning, and the main elements of knowledge transfer in hospitals. They can play a major role in the process of organizational learning. One of the factors affecting nurses' learning is self-efficacy. Objective: The aim of this study was to evaluate the association between organizational learning and professional self-efficacy among nurses. Methodology: A cross-sectional study was conducted among 150 nurses in Ali Ibn Abitaleb Hospital in Zahedan City, Iran in 2018, selected by simple randomized sampling. Tools used were the Neefe Organizational Learning Questionnaire (Neefe, 2001), and Riggs and Knight's Self-Efficacy Questionnaire (1994). Results: The results showed a significant positive correlation (p <0.05) between self-efficacy scores and the organizational learning dimensions of systems thinking, team learning, and shared vision. Linear regression analysis showed that these three dimensions of organizational learning predicted 16.1 of the professional self-efficacy variations. Discussion: Organizational learning has a direct relationship with nurses' professional self-efficacy. Promotion of organizational learning characteristics in hospitals will enhance nurses' self-efficacy. © Copyright 2020 Creative Health Care Management

    Family achievements in struggling with schizophrenia: life experiences in a qualitative content analysis study in Iran

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    Background: The challenges of living with and taking care of a patient with schizophrenia can lead to positive changes depending on the experiences and reactions of family caregivers. Such changes may directly affect the family performance and the patient�s recovery stage. Present study aimed to explain the positive experiences reported by family caregivers of patients with schizophrenia. Methods: The present study is a qualitative study of content analysis. Data were collected using semi-structured and in-depth interviews with 15 family caregivers of patients with schizophrenia referring to one of the psychiatric hospitals in Zahedan, Southeast part of Iran. Purposive sampling method was applied and data analysis was conducted using conventional content analysis proposed by Graneheim and Lundman. Results: Data analysis created a theme entitled �family achievements in struggling with schizophrenia�. This theme included four categories including Developing positive personality traits in family members, Strengthening family ties, developing insight into the life, and social mobility. Conclusions: The results provided insights that the experience of taking care of patients with schizophrenia led to positive consequences for family caregivers. Thus, it is recommended that psychiatrists or consultants help families rely on positive experiences and share these experiences with families with a newly-suffered patient. © 2021, The Author(s)
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