41 research outputs found

    Vapor deposition process provides new method for fabricating high temperature thermocouples

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    Fabrication techniques for high temperature thermocouples bind all components so that differential thermal expansion and contraction do not result in mechanical slippage and localized stress concentrations. Installation space is reduced or larger thermoelements and thicker insulation can be used to improve temperature measurement accuracy

    Interim report on thermocouple sheath development

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    RF and IF mixer optimum matching impedances extracted by large-signal vectorial measurements

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    This paper introduces a new technique that allows us to measure the admittance conversion matrix of a two-port device,using a Nonlinear Vector Network Analyzer.This method is applied to extract the conversion matrix of a 0.2 µµµµm pHEMT,driven by a 4.8 GHz pump signal,at different power levels,using an intermediate frequency of 600 MHz.The issue on data inconsistency due to phase randomization among different measurements is discussed and a proper pre- processing algorithm is proposed to fix the problem. The output of this work consists of a comprehensive experimental evaluation of up-and down-conversion maximum gain,stability,and optimal RF and IF impedances

    Cardiomyocyte Specific Ablation of p53 Is Not Sufficient to Block Doxorubicin Induced Cardiac Fibrosis and Associated Cytoskeletal Changes

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    Doxorubicin (Dox) is an anthracycline used to effectively treat several forms of cancer. Unfortunately, the use of Dox is limited due to its association with cardiovascular complications which are manifested as acute and chronic cardiotoxicity. The pathophysiological mechanism of Dox induced cardiotoxicity appears to involve increased expression of the tumor suppressor protein p53 in cardiomyocytes, followed by cellular apoptosis. It is not known whether downregulation of p53 expression in cardiomyocytes would result in decreased rates of myocardial fibrosis which occurs in response to cardiomyocyte loss. Further, it is not known whether Dox can induce perivascular necrosis and associated fibrosis in the heart. In this study we measured the effects of acute Dox treatment on myocardial and perivascular apoptosis and fibrosis in a conditional knockout (CKO) mouse model system which harbours inactive p53 alleles specifically in cardiomyocytes. CKO mice treated with a single dose of Dox (20 mg/kg), did not display lower levels of myocardial apoptosis or reactive oxygen and nitrogen species (ROS/RNS) compared to control mice with intact p53 alleles. Interestingly, CKO mice also displayed higher levels of interstitial and perivascular fibrosis compared to controls 3 or 7 days after Dox treatment. Additionally, the decrease in levels of the microtubule protein α-tubulin, which occurs in response to Dox treatment, was not prevented in CKO mice. Overall, these results indicate that selective loss of p53 in cardiomyocytes is not sufficient to prevent Dox induced myocardial ROS/RNS generation, apoptosis, interstitial fibrosis and perivascular fibrosis. Further, these results support a role for p53 independent apoptotic pathways leading to Dox induced myocardial damage and highlight the importance of vascular lesions in Dox induced cardiotoxicity

    Multisine signals for wireless system test and design [Application Notes]

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    Correlation-Based Uncertainty in Loaded Reverberation Chambers

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    Vertebral Compression Fractures: Pain Reduction and Improvement in Functional Mobility after Percutaneous Polymethylmethacrylate Vertebroplasty—Retrospective Report of 245 Cases

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    PURPOSE: To describe the immediate outcome of a large cohort of patients who underwent percutaneous polymethylmethacrylate (PMMA) vertebroplasty for treatment of one or more vertebral fractures. MATERIALS AND METHODS: This retrospective cohort study included seven university-based and private hospitals in the United States. Of 488 consecutive patients (mean age, 76 years) who underwent percutaneous PMMA vertebroplasty between 1996 and 1999, 245 were successfully interviewed retrospectively after vertebroplasty (median time, 7 months). Through telephone interview, patients completed our self-developed questionnaire designed to measure pain (10-point scale), ambulation (five-point scale), and ability to perform activities of daily living (ADL) (five-point scale) before and after vertebroplasty. Differences in reported pain, ambulation, and ability to perform ADL before and after vertebroplasty were evaluated with paired t tests. Differences in proportions were compared with the McNemar test. Subgroup analyses were performed to assess the consistency of differences in pre- and postprocedural pain and functional status by patient age, number of fractures, time from fracture to vertebroplasty, and time from vertebroplasty to questionnaire completion. RESULTS: On a 10-point scale, mean pain decreased from 8.9 before vertebroplasty to 3.4 afterward (P .001). Seventy-two percent of patients had substantially impaired ambulation before vertebroplasty compared with 28% afterward (P .001). Ability to perform ADL was also significantly improved following vertebroplasty (P .001). Twelve patients (4.9%) experienced symptomatic complications (none major or life threatening). CONCLUSION: Treatment of vertebral fractures with percutaneous PMMA vertebroplasty appears to be safe and results in substantial immediate pain reduction and improved functional status. A randomized controlled trial appears warranted to assess the efficacy and safety of vertebroplasty
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