579 research outputs found

    The bias-extension test for the analysis of in-plane shear properties of textile composite reinforcements and prepregs: a review

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    The bias-extension test is a rather simple experiment aiming to determine in-plane shear properties of textile composite reinforcements. However the mechanics during the test involves fibrous material at large shear strains and large rotations of the fibres. Several aspects are still being studied and are not yet modeled in a consensual manner. The standard analysis of the test is based on two assumptions: inextensibility of the fibers and rotations at the yarn crossovers without slippage. They lead to the development of zones with constant fibre orientations proper to the bias-extension test. Beyond the analysis of the test within these basic assumptions, the paper presents studies that have been carried out on the lack of verification of these hypothesis (slippage, tension in the yarns, effects of fibre bending). The effects of temperature, mesoscopic modeling and tension locking are also considered in the case of the bias-extension test

    Occupational exposure to formaldehyde and risk of non hodgkin lymphoma: A meta-Analysis

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    Background: Formaldehyde, a widely used chemical, is considered a human carcinogen. We report the results of a meta-Analyses of studies on the relationship between occupational exposure to formaldehyde and risk of non-Hodgkin lymphoma (NHL). Methods: We performed a systematic review and meta-Analysis according to international guidelines and we identified 12 reports of occupational populations exposed to formaldehyde. We evaluated inter-study heterogeneity and we applied a random effects model. We conducted a cumulative meta-Analysis and a meta-Analysis according to estimated average exposure of each study population. Results: The meta-Analysis resulted in a summary relative risk (RR) for NHL of 0.93 (95% confidence interval 0.83-1.04). The cumulative meta-Analysis suggests that higher RRs were detected in studies published before 1986, while studies available after 1986 did not show an association. No differences were found between different levels of occupational exposure. Conclusions Notwithstanding some limitations, the results of this meta-Analysis do not support the hypothesis of an association between occupational exposure to formaldehyde and risk of NHL

    The added value of operator’s judgement in thyroid nodule ultrasound classification arising from histologically based comparison of different risk stratification systems.

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    Objective: Several ultrasound classifications for thyroid nodules were proposed but their accuracy is still debated, since mainly estimated on cytology and not on histology. The aim of this study was to test the diagnostic accuracy and the inter-classification agreement of AACE/ACE-AME, American Thyroid Association (ATA), British Thyroid Association (BTA), and Modena Ultrasound Thyroid Classification (MUT) that stratifies malignancy risk considering also the clinician subjective impression. Methods: A prospective study collecting thyroid nodule features at ultrasound and histological diagnosis was conducted. Ultrasound features were collected following a preformed checklist in candidates for surgery because of indeterminate, suspicious, or malignant cytology. All the nodules, besides the cytologically suspicious one, were blinded analyzed. MUT score was applied prospectively, and the others retrospectively. Sensitivity, specificity, diagnostic cut-off value, and accuracy of each classification were calculated. The overall agreement between classifications was tested by Bland-Altman, and agreement between single nodule analysis by different classifications by Weighted Cohen's Kappa. Results: In classifying a total of 457 nodules, MUT has the highest accuracy (AUC 0.808) and specificity (89%), followed by ATA and BTA, and finally by AACE/ACE-AME. ATA, BTA, and MUT are highly interchangeable. Considering agreement between single nodule analyses, ATA and BTA had the best (κ = 0.723); AACE/ACE-AME showed slight agreement with BTA (κ = 0.177) and MUT (κ = 0.183), and fair agreement with ATA (κ = 0.282); MUT had fair agreement with both ATA (κ = 0.291) and BTA (κ = 0.271). Conclusion: Classifications have an acceptable overall diagnostic accuracy, improved using a less rigid system that takes into consideration operator subjective impression

    Moral Distress in the Pediatric Intensive Care Unit : an Italian Study

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    Introduction: There is paucity of data within the Italian context regarding moral distress in intensive pediatric settings. The aim of the present study was to assess the frequency, intensity, and level of moral distress experienced by nurses working in a sample of pediatric intensive care units (PICUs). Materials and Methods: A cross-sectional questionnaire survey was conducted in eight PICUs from five northern Italian regions in a convenience sample of 136 nurses. Moral distress was evaluated using the modified Italian version of the Moral Distress Scale Neonatal-Pediatric Version (MDSNPV). Each item was scored in terms of frequency and intensity on a five-point Likert scale, ranging from 0 to 4. The total frequency and intensity scores for all the 21 clinical items were comprised between 0 and 84. For each item, the level of moral distress was derived by multiplying the frequency score by the intensity score and quantified with a score ranging from 0 to 16. The total score of the moral distress level for the 21 items ranged from 0 to 336. Results: The mean total scores for the frequency, intensity and level of moral distress were 24.1 \ub1 10.4, 36.2 \ub1 18.6, and 57.7 \ub1 37.1, respectively. The clinical situations identified as the major causes of moral distress among nurses in the present study involved end-of-life care and resuscitation. At multivariate logistic regression analysis, number of deaths occurring in PICUs, having children and intention to leave work due to moral distress resulted to be independently associated with a higher total moral distress level. Conclusions: The results of the present study contribute to the understanding of moral distress experience in acute pediatric care settings, including the clinical situations associated with a higher moral distress level, and highlight the importance of sharing thoughts, feelings and information within the multidisciplinary health care professional team for effective shared decision making, particularly in situations involving end-of-life care and resuscitation

    Whole lifespan microscopic observation of budding yeast aging through a microfluidic dissection platform

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    Important insights into aging have been generated with the genetically tractable and short-lived budding yeast. However, it is still impossible today to continuously track cells by high-resolution microscopic imaging (e.g., fluorescent imaging) throughout their entire lifespan. Instead, the field still needs to rely on a 50-y-old laborious and time-consuming method to assess the lifespan of yeast cells and to isolate differentially aged cells for microscopic snapshots via manual dissection of daughter cells from the larger mother cell. Here, we are unique in achieving continuous and high-resolution microscopic imaging of the entire replicative lifespan of single yeast cells. Our microfluidic dissection platform features an optically prealigned single focal plane and an integrated array of soft elastomer-based micropads, used together to allow for trapping of mother cells, removal of daughter cells, monitoring gradual changes in aging, and unprecedented microscopic imaging of the whole aging process. Using the platform, we found remarkable age-associated changes in phenotypes (e.g., that cells can show strikingly differential cell and vacuole morphologies at the moment of their deaths), indicating substantial heterogeneity in cell aging and death. We envision the microfluidic dissection platform to become a major tool in aging research.

    Effect of a standard schema of self-monitoring blood glucose in patients with poorly controlled, non-insulin-treated type 2 diabetes mellitus: A controlled longitudinal study

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    The effect of self-monitoring of blood glucose (SMBG) on glycemic control with regard to non-insulintreated Type 2 diabetes mellitus (NIT-Type 2 DM) is still a controversial topic. Against this backdrop, we sought to compare the effect of a continuous short-term SMBG schema with as-usual treatment, based on changes in oral antidiabetic treatment in patients with poorly controlled Type 2 DM. We reviewed 492 NIT-Type 2 DM record charts, selecting 27 patients, with poor glycemic control, who were thought to self-monitor their blood glucose levels (SMBG group). We then compared them with 27 patients treated with modifying drugs or diets to achieve and maintain the glycemic target (Control Group). Haemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) were evaluated at baseline, after 3 and 6 months. HbA1c values decreased after 3 and 6 months in the SMBG group (P < 0.001 on both occasions) and in the control group (P < 0.05 and P < 0.01, respectively), but without a significant difference between the two groups when compared at the same time. The FPG progressively decreased in both groups, reaching a significant difference in the SMBG group after 3 months and in the control group after 6 months, and without a significant difference between the two groups. The SMBG schema used in our study could be adopted for target groups before proceeding to the next therapeutic enhancement drug step, representing a useful tool that can help diabetic patients in raising awareness of and treating their disease
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