156 research outputs found

    The rectifying property of polarized barium titanate

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    February 8, 1955.Two titles published in one volume. "Ternary system ethyl alcohol--n--heptane-water at 30 [degrees] C" by Joseph L. Schweppe and James R. Lorah and "The rectifying property of polarized barium titanate" by Donald L. Waidelich.Ternary system ethyl alcohol--n--heptane-water at 30 [degrees] C ; "Reprinted from Industrial and Engineering Chemistry, Vol. 26, November 1954"The rectifying property of polarized barium titanate ; "Reprinted from Journal of the Acoustical Society of America, Vol. 25 July 1953.

    MatricS—A novel tool for monitoring professional role development in surgical disciplines

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    Introduction: Mentoring is an effective method for human resource development. Monitoring the process is important for individual mentee/mentor pairs as well as for program directors. Due to individual personality differences of both mentees and mentors and their respective interactions, it is challenging to monitor the individual development process of mentees in a structured manner. This study investigates to what extent a novel instrument, the mentee-based assessment tool for role development of interpersonal competencies in surgical professions (MatricS) can adequately monitor the professional role development process of residents during an established mentoring program. Material and methods: In a prospective longitudinal study, the competence development of 31 mentees in two subsequent cohorts was assessed by a modified role matrix based on Canadian Medical Education Directives for Specialists. The evaluation focused on three defined roles (D, developer; N, networker; M, multiplicator) at three levels (private, employer-related, national/international) with four stages of development. For validation of mentee self-assessments, the assessments of the respective mentors were recorded alongside. For correlation analyses, Pearson coefficients were calculated, pre-post-comparisons were done by paired t-tests; significance was assumed at p < 0.05, respectively. Results: Mentee self-assessments overall correlated well with the objective mentor assessments (Pearson's r 0.8, p 75% of all roles and levels. Conclusion: The role development process during mentoring can be reliably monitored by using MatricS. MatricS scores highly correlate between mentees and mentors, indicating that mentee self-assessments are suitable and sufficient for monitoring. These findings help to lessen the work burden on senior surgeons and thus can help to increase the acceptance of mentoring programs in surgical disciplines

    Detection of prostate cancer with complexed PSA and complexed/total PSA ratio - is there any advantage?

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    OBJECTIVE: To evaluate the performance of total PSA (tPSA), the free/total PSA ratio (f/tPSA), complexed PSA (cPSA) and the complexed/total PSA ratio (c/tPSA) in prostate cancer detection. METHODS: Frozen sera of 442 patients have been analysed for tPSA, free PSA (fPSA) and cPSA. 131 patients had prostate cancer and 311 patients benign prostatic hyperplasia. RESULTS: Differences in the distribution of the biomarkers were seen as follows: tPSA, cPSA and c/tPSA were significantly higher in the PC group, and f/tPSA was significantly higher in the BPH group. In the tPSA-range of 0-4 ng/ml none of the biomarkers showed a significant difference in the distribution between both groups. In the tPSA-ranges of 0-10 ng/ml, 2-10 ng/ml, 4-10 ng/ml and <10 ng/ml, f/tPSA showed the highest specificity at high sensitivtities, followed by c/tPSA, cPSA, and tPSA, respectively. In tPSA-ranges greater than 10 ng/ml, cPSA offered the best discriminatory ability. GPSA compared to tPSA offered better specificity at high sensitivities in all tPSA-ranges. CONCLUSION: F/tPSA offers the best ability to distinguish between both groups in lower tPSA-ranges, followed by c/tPSA. CPSA compared to tPSA offers a better ability to discriminate between both groups in all PSA-ranges and could be used as an initial test for PC

    Sending Granny to Chiang Mai: debating global outsourcing of care for the elderly

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    This article ties in with existing discussions on global care chains, family separation and the devaluation of social-reproductive work. We explore the new trend of outsourcing care for the elderly to countries with lower wages. We base our analysis on the debate in the German press and supplement it with insights from ethnographic field observations in two care homes in Thailand. We identify a discourse of abandonment, which shows how outsourcing the care of the elderly unsettles the privilege of sedentarism that is often taken for granted in the Global North. Furthermore, the newspaper articles tend to villainize people who seek care for their loved ones abroad. We argue that both discourses foster a neoliberal rationale of individualized responsibility and obfuscate the deep systemic roots of the care crisis in the Global North. However, by extending the discussion on outsourcing care for the elderly beyond the dominant media discourses, we envisage a rich potential for provoking political debate on the revaluation of care

    Methotrexate used in combination with aminolaevulinic acid for photodynamic killing of prostate cancer cells

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    Photodynamic therapy (PDT) using 5-aminolaevulinic acid (ALA) to drive production of an intracellular photosensitiser, protoporphyrin IX (PpIX), is a promising cancer treatment. However, ALA-PDT is still suboptimal for thick or refractory tumours. Searching for new approaches, we tested a known inducer of cellular differentiation, methotrexate (MTX), in combination with ALA-PDT in LNCaP cells. Methotrexate alone promoted growth arrest, differentiation, and apoptosis. Methotrexate pretreatment (1 mg l−1, 72 h) followed by ALA (0.3 mM, 4 h) resulted in a three-fold increase in intracellular PpIX, by biochemical and confocal analyses. After exposure to 512 nm light, killing was significantly enhanced in MTX-preconditioned cells. The reverse order of treatments, ALA-PDT followed by MTX, yielded no enhancement. Methotrexate caused a similar relative increase in PpIX, whether cells were incubated with ALA, methyl-ALA, or hexyl-ALA, arguing against a major effect upon ALA transport. Searching for an effect among porphyrin synthetic enzymes, we found that coproporphyrinogen oxidase (CPO) was increased three-fold by MTX at the mRNA and protein levels. Transfection of LNCaP cells with a CPO-expressing vector stimulated the accumulation of PpIX. Our data suggest that MTX, when used to modulate intracellular production of endogenous PpIX, may provide a new combination PDT approach for certain cancers

    Qualitative and quantitative analyses of protein phosphorylation in naive and stimulated mouse synaptosomal preparations

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    Activity-dependent protein phosphorylation is a highly dynamic yet tightly regulated process essential for cellular signaling. Although recognized as critical for neuronal functions, the extent and stoichiometry of phosphorylation in brain cells remain undetermined. In this study, we resolved activity-dependent changes in phosphorylation stoichiometry at specific sites in distinct subcellular compartments of brain cells. Following highly sensitive phosphopeptide enrichment using immobilized metal affinity chromatography and mass spectrometry, we isolated and identified 974 unique phosphorylation sites on 499 proteins, many of which are novel. To further explore the significance of specific phosphorylation sites, we used isobaric peptide labels and determined the absolute quantity of both phosphorylated and non-phosphorylated peptides of candidate phosphoproteins and estimated phosphorylation stoichiometry. The analyses of phosphorylation dynamics using differentially stimulated synaptic terminal preparations revealed activity-dependent changes in phosphorylation stoichiometry of target proteins. Using this method, we were able to differentiate between distinct isoforms of Ca2+/calmodulin-dependent protein kinase (CaMKII) and identify a novel activity-regulated phosphorylation site on the glutamate receptor subunit GluR1. Together these data illustrate that mass spectrometry-based methods can be used to determine activity-dependent changes in phosphorylation stoichiometry on candidate phosphopeptides following large scale phosphoproteome analysis of brain tissue

    Laser-Anwendung in der Urologie (physikalische und biophysikalische Grundlagen)

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