373 research outputs found

    Qualifications of Bonding Process of Temperature Sensors to Deep-Space Missions

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    A process has been examined for bonding a platinum resistance thermometer (PRT) onto potential aerospace materials such as flat aluminum surfaces and a flexible copper tube to simulate coaxial cables for flight applications. Primarily, PRTs were inserted into a silver-plated copper braid to avoid stresses on the sensor while the sensor was attached with the braid to the base material for long-duration, deep-space missions. A1-1145/graphite composite (planar substrate) and copper tube have been used in this study to assess the reliability of PRT bonding materials. A flexible copper tube was chosen to simulate the coaxial cable to attach PRTs. The substrate materials were cleaned with acetone wipes to remove oils and contaminants. Later, the surface was also cleaned with ethyl alcohol and was air-dried. The materials were gently abraded and then were cleaned again the same way as previously mentioned. Initially, shielded (silver plated copper braid) PRT (type X) test articles were fabricated and cleaned. The base antenna material was pretreated and shielded, and CV-2566 NuSil silicone was used to attach the shielded PRT to the base material. The test articles were cured at room temperature and humidity for seven days. The resistance of the PRTs was continuously monitored during the thermal cycling, and the test articles were inspected prior to, at various intermediate steps during, and at the end of the thermal cycling as well. All of the PRTs survived three times the expected mission life for the JUNO project. No adhesion problems were observed in the PRT sensor area, or under the shielded PRT. Furthermore, the PRT resistance accurately tracked the thermal cycling of the chamber

    Development of a face mask detection pipeline for mask-wearing monitoring in the era of the COVID-19 pandemic: A modular approach

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    During the SARS-Cov-2 pandemic, mask-wearing became an effective tool to prevent spreading and contracting the virus. The ability to monitor the mask-wearing rate in the population would be useful for determining public health strategies against the virus. However, artificial intelligence technologies for detecting face masks have not been deployed at a large scale in real-life to measure the mask-wearing rate in public. In this paper, we present a two-step face mask detection approach consisting of two separate modules: 1) face detection and alignment and 2) face mask classification. This approach allowed us to experiment with different combinations of face detection and face mask classification modules. More specifically, we experimented with PyramidKey and RetinaFace as face detectors while maintaining a lightweight backbone for the face mask classification module. Moreover, we also provide a relabeled annotation of the test set of the AIZOO dataset, where we rectified the incorrect labels for some face images. The evaluation results on the AIZOO and Moxa 3K datasets showed that the proposed face mask detection pipeline surpassed the state-of-the-art methods. The proposed pipeline also yielded a higher mAP on the relabeled test set of the AIZOO dataset than the original test set. Since we trained the proposed model using in-the-wild face images, we can successfully deploy our model to monitor the mask-wearing rate using public CCTV images.Comment: Accepted at the 19th International Joint Conference on Computer Science and Software Engineering (JCSSE 2022

    Pilot study to investigate differences in middle molecules, oxidative stress and markers of peripheral vascular disease in patients treated by high flux haemodialysis and haemodiafiltration

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    BACKGROUND: Dialysis patients have an increased risk of mortality. Recently treatment with haemodiafiltration (HDF) has been reported to reduce mortality, particularly cardiovascular mortality, compared to standard high-flux haemodialysis (HD). However, why HDF may offer a survival advantage remains to be determined. So, we conducted a pilot study to explore differences in middle-molecules, inflammation and markers of vascular disease in patients treated by HD and HDF. METHODS: Observational cross-sectional study measuring serum β2-microglobulin (β2M), Advanced Glycosylation End Products (AGEs) by skin autofluorescence (SAF), oxidative stress with ischaemia modified albumin ratio (IMAR) and peripheral vascular disease assessment using Ankle-Brachial Index (ABI), and arterial stiffness using Cardio-Ankle Vascular Index (CAVI). RESULTS: We studied 196 patients, mean age 69.1 ± 12.4 years, 172 (87.8%) treated by HD and 24 (12.2%) by HDF. Age, body mass index, co-morbidity and dialysis vintage were not different between HD and HDF groups. Middle molecules; β2M (31±9.9 vs 31.2±10 ug/mL) and SAF (2.99±0.72 vs 3.0±0.84 AU), ABI (1.06±0.05 vs 1.07±0.10) and CAVI (9.34±1.55 vs 9.35±1.23) were not different, but IMAR was higher in the HD patients (38.4±14.8 vs 31.3 ± 17.4, P = 0.035). CONCLUSIONS: In this pilot observational study, we found patients treated by HDF had lower oxidative stress as measured by IMAR, with no differences in middle molecules. Lower oxidative stress would be expected to have diverse protective effects on the cardiovascular system Although we found no differences in ABI and CAVI, future studies are required to determine whether reduced oxidative stress translates into clinically relevant differences over time

    Bioimpedance Analysis-Guided Volume Expansion for the Prevention of Contrast-Induced Acute Kidney Injury (the BELIEVE Pilot Randomized Controlled Trial)

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    Introduction: Peri-procedural i.v. fluid administration is important for the prevention of contrast-induced acute kidney injury (CI-AKI). However, standardized fluid management protocols may not be suitable for all patients. We therefore wished to determine whether an individualized fluid administration protocol guided by measuring extracellular water (ECW) using bioimpedance analysis (BIA) would be safe and would reduce the incidence CI-AKI compared to a standardized fluid administration prescription. Methods: In this pilot, randomized, parallel-group, single-blind, controlled trial, we compared the effect of BIA-guided isotonic bicarbonate administration according to the ratio of ECW to total body water (ECW/TBW) to our standard isotonic bicarbonate protocol in regard to the safety and efficacy of preventing CI-AKI in chronic kidney disease patients undergoing elective cardiac angiography. Our primary outcome was the incidence of CI-AKI, which was defined as a ≥0.3 mg/dl or 150% increase in serum creatinine concentration within 48 to 72 hours after cardiac angiography. Results: We studied 61 patients, 30 in the bioimpedance group and 31 in the control group. Age was similar (72.5 ± 7 vs. 71.4 ± 7.9 years), as were body mass index (25.5 vs. 25.8 kg/m2) and baseline serum creatinine (1.3 ± 0.3 vs. 1.4 ± 0.4 mg/dl). The peri-procedural fluid volume administered was significantly greater in the BIA-guided hydration group (899.0 ± 252.7 ml vs. 594.4 ± 125.9 ml, P < .01). The incidence of CI-AKI was 3.3% in BIA-guided hydration group and 6.5% in the control group (relative risk = 0.52, 95% confidence interval = 0.05−5.40, P = 1.00). Adverse events reported were comparable between groups (6.7% vs. 6.5%, P = 1.00). Conclusions: The overall incidence of CI-AKI after cardiac angiography in our patients with mild-to-moderate renal insufficiency was lower than anticipated. Isotonic bicarbonate administration guided by bioimpedance measurements was safe, and probably led to a lower incidence of CI-AKI, although this not reach statistical significance

    Regional differences in admissions and treatment outcomes for hepatocellular carcinoma patients in Thailand

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    Background: Hepatocellular carcinoma (HCC) is one of the commonest cancers in Thailand. We report the stage and survival of patients who were admitted under the public universal health fund (NHSO) covering 47 million people to determine if there were regional disparities in the treatment outcomes in the country. Method: We used the 2009-2013 Nationwide Hospital Admission Data, Thailand. Patients with hepatocellular carcinoma (HCC) were identified by the ICD10 code C22.0. Procedures were identified by ICD9-CM codes, and deaths were confirmed from the NHSO database and the national citizen registry. Thailand is divided into 6 regions and Bangkok. Hospitals were identified according to their specific reimbursement codes. Survival time started from the day of first admission and was estimated using the Kaplan-Meier method. The statistical method used to compare regions was Chi-squared tests (Pearson, likelihood ratio, linear-by linear association and Mantel-cox). Results: There were 36,956 HCC patients admitted during the study period. The overall median survival was 36 days. 1.63% of the patients had surgery, 0.96% had radiofrequency ablation (RFA), and 5.24% had trans-arterial chemoembolization (TACE). 90.24% did not have any tumor-specific therapy. The proportion of patients admitted for tumor-specific therapy vs. no tumor-specific therapy was significantly different between regions in all treatment modalities (p<0.01). Each treatment modality showed a wide range of median survival values across the regions (p<0.01). The best survival was seen in Bangkok, the South and the North (for surgery, RFA and TACE) and was often more than twice as long as the regions with the lowest survival, Central, East and West. Conclusions: There was a large previously-unreported disparity in admissions and outcomes in Thailand for different treatment modalities for HCC. Bangkok and the South had the best treatment outcomes and often had median survivals more than twice as long as those in the West and East. Public policy to reduce this disparity will need to be implemented in the future

    Incomplete Distal Renal Tubular Acidosis with Nephrocalcinosis

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    We report the case of a female patient with incomplete distal renal tubular acidosis with nephrocalcinosis. She was admitted to the hospital because of acute pyelonephritis. Imaging studies showed dual medullary nephrocalcinosis. Subsequent evaluations revealed hypokalemia, hypocalcemia, hypercalciuria, and hypocitraturia with normal acid-base status. A modified tubular acidification test with NH4Cl confirmed a defect of urine acidification, which is compatible with incomplete distal tubular acidosis. We treated our patient with potassium citrate, which corrects hypokalemia and prevents further deposition of calcium salts

    Roles of kininogen-1, basement membrane specific heparan sulfate proteoglycan core protein, and roundabout homolog 4 as potential urinary protein biomarkers in diabetic nephropathy

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    Diabetic nephropathy, a major complication of diabetes mellitus (DM), is increasing worldwide and the large majority of patients have type 2 DM. Microalbuminuria has been used as a diagnostic marker of diabetic nephro­pathy. But owing to its insufficient sensitivity and specificity, other biomarkers are being sought. In addition, the pathophysiology of diabetic nephropathy is not fully understood and declines in renal function occur even without microalbuminuria. In this study, we investigated urinary proteins from three study groups (controls, and type 2 diabetic subjects with or without microalbuminuria). Non-targeted label-free Nano-LC QTOF analysis was conducted to discover underlying mechanisms and protein networks, and targeted label-free Nano-LC QTOF with SWATH was performed to qualify discovered protein candidates. Twenty-eight proteins were identified as candidates and functionally analyzed via String DB, gene ontology and pathway analysis. Four predictive mechanisms were analyzed: i) response to stimulus, ii) platelet activation, signaling and aggregation, iii) ECM-receptor interaction, and iv) angiogenesis. These mechanisms can provoke kidney dysfunction in type 2 diabetic patients via endothelial cell damage and glomerulus structural alteration. Based on these analyses, three proteins (kininogen-1, basement membrane-specific heparan sulfate proteoglycan core protein, and roundabout homolog 4) were proposed for further study as potential biomarkers. Our findings provide insights that may improve methods for both prevention and diagnosis of diabetic nephropathy

    Involvement of the renin–angiotensin system in the development of vascular damage in a rat model of arthritis: Effect of angiotensin receptor blockers

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    Objective To explore the involvement of the renin–angiotensin system (RAS) in the development of vascular damage in adjuvant-induced arthritis (AIA) in rats. Methods Angiotensin II (Ang II; 0.25 or 1.0 mg/kg/day) was infused in control rats and rats with AIA for 21 days, and the impact of systemic inflammation on Ang II–induced hypertension, endothelial dysfunction, and vascular hypertrophy was evaluated. Expression of angiotensin II type 1 receptor (AT 1 R) and angiotensin-converting enzyme (ACE) in the aortas of rats with AIA were examined by real-time polymerase chain reaction (PCR) and Western blot analyses. Losartan (3 mg/kg/day) or irbesartan (5 mg/kg/day), both of which are AT 1 R blockers, was administered orally to rats with AIA for 21 days. In situ superoxide production in aortas was assessed according to the fluorogenic oxidation of dihydroethidium to ethidium. The expression and activity of NAD(P)H oxidases in aortas were examined by real-time PCR analysis and lucigenin chemiluminescence assay. Endothelial function in rats with AIA treated in vivo or ex vivo with AT 1 R blockers was also determined. Results The Ang II–induced hypertensive response, endothelial dysfunction, and vascular hypertrophy were exacerbated in rats with AIA. Expression of AT 1 R and ACE was increased in the aortas of rats with AIA. Both losartan and irbesartan decreased the levels of superoxide and the expression and activity NAD(P)H oxidases in the aortas of rats with AIA. The endothelial dysfunction in AIA was improved by the in vivo or ex vivo treatment with AT 1 R blockers. Conclusion The locally activated RAS is involved in the increased vascular oxidative stress and endothelial dysfunction in AIA. Our findings have important implications for clinical approaches to the reduction of cardiovascular risk in patients with rheumatoid arthritis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75773/1/27384_ftp.pd

    Fluvastatin reverses endothelial dysfunction and increased vascular oxidative stress in rat adjuvant-induced arthritis

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    Objective To investigate the effect of statins on vascular dysfunction in rat adjuvant-induced arthritis (AIA). Methods Fluvastatin (5 mg/kg/day) was administered orally to rats with AIA, for 21 days after the onset of arthritis. The vasodilatory response to acetylcholine of aortic rings isolated from rats with AIA that were not treated or were treated with fluvastatin and from normal rats was determined. The amounts of 4-hydroxy-2-nonenal (HNE) and nitrotyrosine in aortas were measured by Western blotting. In vitro and in situ superoxide production in aortas was evaluated based on fluorogenic oxidation of dihydroethidium to ethidium. Expression of NAD(P)H components and endothelial nitric oxide synthase (eNOS) in aortas was examined by real-time reverse transcriptase–polymerase chain reaction and Western blotting. Serum levels of tetrahydrobiopterin, a critical eNOS cofactor, were determined by high-performance liquid chromatography. Results Fluvastatin reversed endothelial dysfunction in AIA without affecting the clinical severity of arthritis or serum cholesterol concentration. Fluvastatin reduced the amounts of HNE and nitrotyrosine in the aorta, and the levels of superoxide expressed in endothelial cells and smooth muscle cells in the tissue, in rats with AIA. NADH- or L -arginine–induced superoxide production was not observed in the aortic samples from fluvastatin-treated rats with AIA. Fluvastatin decreased the levels of expression of messenger RNA for p22phox, a NAD(P)H oxidase component, in the aortas of rats with AIA, but did not affect the expression of eNOS. Serum levels of tetrahydrobiopterin were significantly reduced in rats with AIA, and were increased by administration of fluvastatin. Conclusion Our findings demonstrate that fluvastatin has potent vascular protective effects in AIA and provide additional scientific rationale for the use of statins to reduce cardiovascular mortality in patients with rheumatoid arthritis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56040/1/22632_ftp.pd
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