50 research outputs found

    Effect of Tensile and Compressive Stress on Martensitic Transformation and Deformation Behavior of Cu-Al-Ni Alloys (Supplement)

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    A supplemental study has been carried out on the effect of tensile and compressive stress on martensitic transformation and deformation behavior of Cu-Al-Ni alloys. The stress-strain behavior obtained in tension and compression tests with separate specimens were fundamentally similar to those in the previous tension-compression tests with single specimens. However, in compression tests for β_1 single crystals, it was newly found that a temperature dependence of the β_1→β_1\u27 or β_1→γ_1\u27 transformation stress depended on the orientation of specimens. In compression tests for single variant γ_1\u27 martensites below M_f, the deformation mode was found to be {121}_ twinning with the maximum Schmid factor but not {101}_ twinning. Tension-compression tests with an extensometer were fundamentally similar to the previous ones without an extensometer as to the temperature dependence of stress-strain behavior. Larger temperature dependence of critical stress and its resolved shear stress for the β_1→β_1\u27 and β_1→γ_1\u27 transformations on compression side than those on tension side was attributed to a different transformation strain due to the formation of different variants of martensites on tension and compression sides

    A Case of Pancreatic Ascites and Pleural Effusion: Confirmation of a Pancreatic Duct Contrast Leakage Using Computed Tomography after Endoscopic Retrograde Cholangiopancreatography

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    A seventy-two year old Japanese man with chronic alcoholism was admitted with increasing epigastric pain and abdominal fullness. He gave a history of bouts of epigastric pain radiating to the back for the past year. At admission, abdominal ultrasonography and computed tomography (CT) demonstrated massive ascites and a pseudocyst in the pancreatic body. A chest X-ray showed bilateral pleural effusion, and the level of amylase was elevated in the serum, urine, ascitic fluid and pleural effusion. First, the patient was treated with nothing by mouth but with intravenous hyperalimentation, however, no improvement was noted after 2 weeks. Then, the patient underwent endoscopic retrograde cholangiopancreatography (ERCP) and abdominal CT after ERCP. They showed irregular dilatation of the pancreatic main duct and branch, and an extravasation of contrast media from the pancreatic duct into the peritoneal cavity, after which the patient underwent surgery. Because no fistula was found during surgery, drainages were retained into the pseudocyst and peritoneal cavity. Due to marked elevation of amylase and protein levels in ascitic fluid and pleural effusion and findings from ERCP and CT after ERCP, pancreatic ascites and pleural effusion was diagnosed. The diagnosis of chronic pancreatitis is due to his history, laboratory data, and irregular dilatation of the pancreatic duct on ERCP. After surgery, his clinical status improved rapidly. We thus described a case of pancreaticoperitoneal fistula demonstrated by CT scan subsequent to ERCP which was treated successfully by surgery

    Out-of-hospital endotracheal intubation experience, confidence and confidence-associated factors among Northern Japanese emergency life-saving technicians: a population-based cross-sectional study

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    OBJECTIVE: Clinical procedural experience and confidence are both important when performing complex medical procedures. Since out-of-hospital endotracheal intubation (ETI) is a complex intervention, we sought to clarify clinical ETI experience among prehospital rescuers as well as their confidence in performing ETI and confidence-associated factors. DESIGN: Population-based cross-sectional study conducted from January to September 2017. SETTING: Northern Japan, including eight prefectures. PARTICIPANTS: Emergency life-saving technicians (ELSTs) authorised to perform ETI. OUTCOME MEASURES: Annual ETI exposure and confidence in performing ETI, according to a five-point Likert scale. To determine factors associated with ETI confidence, differences between confident ELSTs (those scoring 4 or 5 on the Likert scale) and non-confident ELSTs were evaluated. RESULTS: Questionnaires were sent to 149 fire departments (FDs); 140 agreed to participate. Among the 2821 ELSTs working at responding FDs, 2620 returned the questionnaire (response rate, 92.9%); complete data sets were available for 2567 ELSTs (complete response rate, 91.0%). Of those 2567 respondents, 95.7% performed two or fewer ETI annually; 46.6% reported lack of confidence in performing ETI. Multivariable logistic regression analysis showed that years of clinical experience (adjusted OR (AOR) 1.09; 95% CI 1.05 to 1.13), annual ETI exposure (AOR 1.79; 95% CI 1.59 to 2.03) and the availability of ETI skill retention programmes including regular simulation training (AOR 1.31; 95% CI 1.02 to 1.68) and operating room training (AOR 1.44; 95% CI 1.14 to 1.83) were independently associated with confidence in performing ETI. CONCLUSIONS: ETI is an uncommon event for most ELSTs, and nearly half of respondents did not have confidence in performing this procedure. Since confidence in ETI was independently associated with availability of regular simulation and operating room training, standardisation of ETI re-education that incorporates such methods may be useful for prehospital rescuers

    Serological Surveillance Development for Tropical Infectious Diseases Using Simultaneous Microsphere-Based Multiplex Assays and Finite Mixture Models

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    Background:A strategy to combat infectious diseases, including neglected tropical diseases (NTDs), will depend on the development of reliable epidemiological surveillance methods. To establish a simple and practical seroprevalence detection system, we developed a microsphere-based multiplex immunoassay system and evaluated utility using samples obtained in Kenya.Methods:We developed a microsphere-based immuno-assay system to simultaneously measure the individual levels of plasma antibody (IgG) against 8 antigens derived from 6 pathogens: Entamoeba histolytica (C-IgL), Leishmania donovani (KRP42), Toxoplasma gondii (SAG1), Wuchereria bancrofti (SXP1), HIV (gag, gp120 and gp41), and Vibrio cholerae (cholera toxin). The assay system was validated using appropriate control samples. The assay system was applied for 3411 blood samples collected from the general population randomly selected from two health and demographic surveillance system (HDSS) cohorts in the coastal and western regions of Kenya. The immunoassay values distribution for each antigen was mathematically defined by a finite mixture model, and cut-off values were optimized.Findings:Sensitivities and specificities for each antigen ranged between 71 and 100%. Seroprevalences for each pathogen from the Kwale and Mbita HDSS sites (respectively) were as follows: HIV, 3.0% and 20.1%; L. donovani, 12.6% and 17.3%; E. histolytica, 12.8% and 16.6%; and T. gondii, 30.9% and 28.2%. Seroprevalences of W. bancrofti and V. cholerae showed relatively high figures, especially among children. The results might be affected by immunological cross reactions between W. bancrofti-SXP1 and other parasitic infections; and cholera toxin and the enterotoxigenic E. coli (ETEC), respectively.Interpretation:A microsphere-based multi-serological assay system can provide an opportunity to comprehensively grasp epidemiological features for NTDs. By adding pathogens and antigens of interest, optimized made-to-order high-quality programs can be established to utilize limited resources to effectively control NTDs in Africa

    Non-invasive diagnostic tests for Helicobacter pylori infection

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    BACKGROUND: Helicobacter pylori (H pylori) infection has been implicated in a number of malignancies and non-malignant conditions including peptic ulcers, non-ulcer dyspepsia, recurrent peptic ulcer bleeding, unexplained iron deficiency anaemia, idiopathic thrombocytopaenia purpura, and colorectal adenomas. The confirmatory diagnosis of H pylori is by endoscopic biopsy, followed by histopathological examination using haemotoxylin and eosin (H & E) stain or special stains such as Giemsa stain and Warthin-Starry stain. Special stains are more accurate than H & E stain. There is significant uncertainty about the diagnostic accuracy of non-invasive tests for diagnosis of H pylori. OBJECTIVES: To compare the diagnostic accuracy of urea breath test, serology, and stool antigen test, used alone or in combination, for diagnosis of H pylori infection in symptomatic and asymptomatic people, so that eradication therapy for H pylori can be started. SEARCH METHODS: We searched MEDLINE, Embase, the Science Citation Index and the National Institute for Health Research Health Technology Assessment Database on 4 March 2016. We screened references in the included studies to identify additional studies. We also conducted citation searches of relevant studies, most recently on 4 December 2016. We did not restrict studies by language or publication status, or whether data were collected prospectively or retrospectively. SELECTION CRITERIA: We included diagnostic accuracy studies that evaluated at least one of the index tests (urea breath test using isotopes such as13C or14C, serology and stool antigen test) against the reference standard (histopathological examination using H & E stain, special stains or immunohistochemical stain) in people suspected of having H pylori infection. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the references to identify relevant studies and independently extracted data. We assessed the methodological quality of studies using the QUADAS-2 tool. We performed meta-analysis by using the hierarchical summary receiver operating characteristic (HSROC) model to estimate and compare SROC curves. Where appropriate, we used bivariate or univariate logistic regression models to estimate summary sensitivities and specificities. MAIN RESULTS: We included 101 studies involving 11,003 participants, of which 5839 participants (53.1%) had H pylori infection. The prevalence of H pylori infection in the studies ranged from 15.2% to 94.7%, with a median prevalence of 53.7% (interquartile range 42.0% to 66.5%). Most of the studies (57%) included participants with dyspepsia and 53 studies excluded participants who recently had proton pump inhibitors or antibiotics.There was at least an unclear risk of bias or unclear applicability concern for each study.Of the 101 studies, 15 compared the accuracy of two index tests and two studies compared the accuracy of three index tests. Thirty-four studies (4242 participants) evaluated serology; 29 studies (2988 participants) evaluated stool antigen test; 34 studies (3139 participants) evaluated urea breath test-13C; 21 studies (1810 participants) evaluated urea breath test-14C; and two studies (127 participants) evaluated urea breath test but did not report the isotope used. The thresholds used to define test positivity and the staining techniques used for histopathological examination (reference standard) varied between studies. Due to sparse data for each threshold reported, it was not possible to identify the best threshold for each test.Using data from 99 studies in an indirect test comparison, there was statistical evidence of a difference in diagnostic accuracy between urea breath test-13C, urea breath test-14C, serology and stool antigen test (P = 0.024). The diagnostic odds ratios for urea breath test-13C, urea breath test-14C, serology, and stool antigen test were 153 (95% confidence interval (CI) 73.7 to 316), 105 (95% CI 74.0 to 150), 47.4 (95% CI 25.5 to 88.1) and 45.1 (95% CI 24.2 to 84.1). The sensitivity (95% CI) estimated at a fixed specificity of 0.90 (median from studies across the four tests), was 0.94 (95% CI 0.89 to 0.97) for urea breath test-13C, 0.92 (95% CI 0.89 to 0.94) for urea breath test-14C, 0.84 (95% CI 0.74 to 0.91) for serology, and 0.83 (95% CI 0.73 to 0.90) for stool antigen test. This implies that on average, given a specificity of 0.90 and prevalence of 53.7% (median specificity and prevalence in the studies), out of 1000 people tested for H pylori infection, there will be 46 false positives (people without H pylori infection who will be diagnosed as having H pylori infection). In this hypothetical cohort, urea breath test-13C, urea breath test-14C, serology, and stool antigen test will give 30 (95% CI 15 to 58), 42 (95% CI 30 to 58), 86 (95% CI 50 to 140), and 89 (95% CI 52 to 146) false negatives respectively (people with H pylori infection for whom the diagnosis of H pylori will be missed).Direct comparisons were based on few head-to-head studies. The ratios of diagnostic odds ratios (DORs) were 0.68 (95% CI 0.12 to 3.70; P = 0.56) for urea breath test-13C versus serology (seven studies), and 0.88 (95% CI 0.14 to 5.56; P = 0.84) for urea breath test-13C versus stool antigen test (seven studies). The 95% CIs of these estimates overlap with those of the ratios of DORs from the indirect comparison. Data were limited or unavailable for meta-analysis of other direct comparisons. AUTHORS' CONCLUSIONS: In people without a history of gastrectomy and those who have not recently had antibiotics or proton ,pump inhibitors, urea breath tests had high diagnostic accuracy while serology and stool antigen tests were less accurate for diagnosis of Helicobacter pylori infection.This is based on an indirect test comparison (with potential for bias due to confounding), as evidence from direct comparisons was limited or unavailable. The thresholds used for these tests were highly variable and we were unable to identify specific thresholds that might be useful in clinical practice.We need further comparative studies of high methodological quality to obtain more reliable evidence of relative accuracy between the tests. Such studies should be conducted prospectively in a representative spectrum of participants and clearly reported to ensure low risk of bias. Most importantly, studies should prespecify and clearly report thresholds used, and should avoid inappropriate exclusions

    Specific Chromatographic Retentions on Polymer Pore Surface of Macroporous Spongy Monoliths

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    We examined chromatographic retention properties of macroporous spongy monolithic columns. Detailed chromatographic evaluations showed that planar compounds were strongly retained on poly(ethylene-co-vinyl acetate)-based monoliths, whereas sterically bulky or hydrophilic compounds were weakly retained. The comparison results with commonly used columns suggested that the specific retention abilities were a result of the differences in the polymer-chain orientation on polymer pore surface

    Transcriptional Regulation of Acyl-CoA:Glycerol-<i>sn</i>-3-Phosphate Acyltransferases

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    Acyl-CoA:glycerol-sn-3-phosphate acyltransferase (GPAT) is an enzyme responsible for the rate-limiting step in the synthesis of glycerophospholipids and triacylglycerol (TAG). The enzymes of mammalian species are classified into four isoforms; GPAT1 and GPAT2 are localized in the mitochondrial outer membrane, whereas GPAT3 and GPAT4 are localized in the endoplasmic reticulum membrane. The activity of each enzyme expressed is associated with physiological and pathological functions. The transcriptional regulation is well known, particularly in GPAT1. GPAT1 mRNA expression is mainly regulated by the binding of the transcriptional factor SREBP-1c to the specific element (the sterol regulatory element) flanking the GPAT1 promoter. The TAG level is controlled by the insulin-induced transcriptional expression of GPAT1, which occupies most of the GPAT activity in the liver. The transcriptional regulation of the other three GPAT isoforms remains undetermined in detail. It is predicted that retinoic acid serves as a transcription factor in the GPAT2 promoter. PPAR&#947; (peroxisome proliferator-activated receptor &#947;) increases the mRNA expression of GPAT3, which is associated with TAG synthesis in adipose tissues. Although GPAT has been considered to be a key enzyme in the production of TAG, unexpected functions have recently been reported, particularly in GPAT2. It is likely that GPAT2 is associated with tumorigenesis and normal spermatogenesis. In this review, the physiological and pathophysiological roles of the four GPAT isoforms are described, alongside the transcriptional regulation of these enzymes

    Congenital Erythropoietic Porphyria.

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    Data from: Out-of-hospital endotracheal intubation experience, confidence, and confidence-associated factors among Northern Japanese emergency life-saving technicians: a population-based cross-sectional study

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    Objective: Clinical procedural experience and confidence are both important when performing complex medical procedures. Because out-of-hospital endotracheal intubation (ETI) is a complex intervention, we sought to clarify clinical ETI experience among prehospital rescuers as well as their confidence in performing ETI and confidence-associated factors. Design: Population-based cross-sectional study conducted from January to September 2017. Setting: Northern Japan, including eight prefectures. Participants: Emergency life-saving technicians (ELSTs) authorized to perform ETI. Outcome measures: Annual ETI exposure and confidence in performing ETI, according to a 5-point Likert scale. To determine factors associated with ETI confidence, differences between confident ELSTs (those scoring 4 or 5 on the Likert scale) and non-confident ELSTs were evaluated. Results: Questionnaires were sent to 149 fire departments; 140 agreed to participate. Among the 2821 ELSTs working at responding fire departments, 2620 returned the questionnaire (response rate, 92.9%); complete data sets were available for 2567 ELSTs (complete response rate, 91.0%). Of those 2567 respondents, 95.7% performed two or fewer ETI annually; 46.6% reported lack of confidence in performing ETI. Multivariable logistic regression analysis showed that years of clinical experience (adjusted odds ratio [AOR], 1.09; 95% confidence interval [CI], 1.05–1.13), annual ETI exposure (AOR, 1.79; 95% CI, 1.59–2.03), and the availability of ETI skill retention programs including regular simulation training (AOR, 1.31; 95% CI, 1.02–1.68) and operating room training (AOR, 1.44; 95% CI, 1.14–1.83) were independently associated with confidence in performing ETI. Conclusions: ETI is an uncommon event for most ELSTs and nearly half of respondents did not have confidence in performing this procedure. Because confidence in ETI was independently associated with availability of regular simulation and operating room training, standardization of ETI reeducation that incorporates such methods may be useful for prehospital rescuers
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