Determination of Aggregate Elastic Properties of Powder-Beds in Additive Manufacturing Using Convolutional Neural Networks

The most popular strategy for the estimation of effective elastic properties of powder-beds in Additively Manufactured structures (AM structures) is through either the Finite Element Method (FEM) or the Discrete Element Method (DEM). Both of these techniques, however, are computationally expensive for practical applications. This paper presents a novel Convolutional Neural Network (CNN) regression approach to estimate the effective elastic properties of powder-beds in AM structures. In this approach, the time-consuming DEM is used for CNN training purposes and not at run time. The DEM is used to model the interactions of powder particles and to evaluate the macro-level continuum-mechanical state variables (volume average of stress and strain). For the Neural Network training purposes, the DEM code creates a dataset, including hundreds of AM structures with their corresponding mechanical properties. The approach utilizes methods from deep learning to train a CNN capable of reducing the computational time needed to predict the effective elastic properties of the aggregate. The saving in computational time could reach 99.9995% compared to DEM, and on average, the difference in predicted effective elastic properties between the DEM code and trained CNN is less than 4%. The resulting sub-second level computational time can be considered as a step towards the development of a near real-time process control system capable of predicting the effective elastic properties of the aggregate at any given stage of the manufacturing process

Comparative study of efficacy and safety of intravenous ferric carboxy maltose versus iron sucrose in treatment of postpartum iron deficiency anemia

Background: As postpartum iron deficiency anemia is observed in about 65% of women in India, it is the major contributing factor and indirect cause of maternal death. Postpartum anemia may lead to postpartum depression, stress, anxiety and cognitive impairment. Adequate treatment of anemia in postpartum period will have improved life quality in women in child bearing age so this study was designed with the objective to compare the safety and efficacy of intravenous FCM versus iron sucrose in treatment of postpartum iron deficiency anemia.Methods: It was a prospective observational study of postpartum women (within 10 days of delivery) with iron deficiency anemia (7-9 gm%) who delivered in LG hospital, Ahmedabad. A sample size of 215 women was estimated based on prevalence of anemia which is 65% among postpartum women in India including dropout rate of 10% which were further divided into 2 groups. Group 1: iron sucrose group, Group 2: ferric carboxy maltose group.Results: FCM has greater rise in Hb, less side effects, and easy administration of dose as compared to iron sucrose. The rise in Hb with FCM as compared to iron sucrose is (4.6 versus 3.5 respectively).Conclusions: FCM has more safety and efficacy as compared to iron sucrose in treatment of postpartum iron deficiency anemia

Willingness to participate in a randomized trial comparing catheters to fistulas for vascular access in incident hemodialysis patients: an international survey of nephrologists

BACKGROUND: Current guidelines favor fistulas over catheters as vascular access. Yet, the observational literature comparing fistulas to catheters has important limitations and biases that may be difficult to overcome in the absence of randomization. However, it is not clear if physicians would be willing to participate in a clinical trial comparing fistulas to catheters. OBJECTIVES: We also sought to elicit participants' opinions on willingness to participate in a future trial regarding catheters and fistulas. DESIGN: We created a three-part survey consisting of 19 questions. We collected demographic information, respondents' knowledge of the vascular access literature, appropriateness of current guideline recommendations, and their willingness to participate in a future trial. SETTING: Participants were recruited from Canada, Europe, Australia, and New Zealand. PARTICIPANTS: Participants include physicians and trainees who are involved in the care of end-stage renal disease patients requiring vascular access. MEASUREMENTS: Descriptive statistics were used to describe baseline characteristics of respondents according to geographic location. We used logistic regression to model willingness to participate in a future trial. METHODS: We surveyed nephrologists from Canada, Europe, Australia, and New Zealand to assess their willingness to participate in a randomized trial comparing fistulas to catheters in incident hemodialysis patients. RESULTS: Our results show that in Canada, 86 % of respondents were willing to participate in a trial (32 % in all patients; 54 % only in patients at high risk of primary failure). In Europe and Australia/New Zealand, the willingness to participate in a trial that included all patients was lower (28 % in Europe; 25 % in Australia/New Zealand), as was a trial that included patients at high risk of primary failure (38 % in Europe; 39 % in Australia/New Zealand). Nephrologists who have been in practice for a few years, saw a larger volume of patients, or self-identified as experts in vascular access literature were more likely to participate in a trial. LIMITATIONS: Survey distribution was limited to vascular access experts in participating European countries and ultimately led to a discrepancy in numbers of European to non-European respondents overall. Canadian views are likely over-represented in the overall outcomes. CONCLUSIONS: Our survey results suggest that nephrologists believe there is equipoise surrounding the optimal vascular access strategy and that a randomized controlled study should be undertaken, but restricted to those individuals with a high risk of primary fistula failure

Effects of lockdown on emergency room admissions for psychiatric evaluation: an observational study from the AUSL Romagna, Italy

Objectives: An observation of the admissions to the emergency room (ER) requiring psychiatric evaluation during the lockdown and investigation of the demographic and clinical variables. Methods: Retrospective longitudinal observational study of ER accesses for psychiatric evaluation was performed, comparing two periods (9 March–3 May 2020 vs. 9 March–3 May 2019). Data (number of admissions, key baseline demographic and clinical variables) were extracted from the ER databases of referral centres in a well-defined geographic area of North-Eastern Italy (Cesena, Ravenna, Forlì, and Rimini). Results: A 15% reduction of psychiatric referrals was observed, together with a 17% reduction in the total number of patients referring to the ER. This reduction was most evident in the first month of the lockdown period (almost 25% reduction of both referrals and patients). Female gender (OR: 1.52: 95%, CI: 1.12–2.06) and being a local resident (OR: 1.54: 95%CI: 1.02–2.34) were factors associated with the decrease. Conclusions: Lockdown changed dramatically health priorities in the local population, including people with mental health. We speculate that our observations do not only refer to the confinement due to the lockdown regime but also to fear of contagion and adoption of different coping strategies, especially in women.Key-points During lockdown 15% reduction of psychiatric visits and >17% reduction in the number of psychiatric patients referring to the ER was observed. in the first four weeks of the lockdown almost 25% reduction of both visits and patients was observed Female gender and being a local resident were factors associated with the decrease

Kidney Function, Albuminuria and Life Expectancy

Background: Lower estimated glomerular filtration rate is associated with reduced life expectancy. Whether this association is modified by the presence or absence of albuminuria, another cardinal finding of chronic kidney disease, is unknown. Objective: Our objective was to estimate the life expectancy of middle-aged men and women with varying levels of eGFR and concomitant albuminuria. Design: A retrospective cohort study. Setting: A large population-based cohort identified from the provincial laboratory registry in Alberta, Canada. Participants: Adults aged ≥30 years who had outpatient measures of serum creatinine and albuminuria between May 1, 2002 and March 31, 2008. Measurements: Predictor : Baseline levels of kidney function identified from serum creatinine and albuminuria measurements. Outcomes : all cause mortality during the follow-up. Methods: Patients were categorized based on their estimated glomerular filtration rate (eGFR) (≥60, 45–59, 30–44, and 15–29 mL/min/1 · 73 m 2 ) as well as albuminuria (normal, mild, and heavy) measured by albumin-to-creatinine ratio or urine dipstick. The abridged life table method was applied to calculate the life expectancies of men and women from age 40 to 80 years across combined eGFR and albuminuria categories. We also categorized participants by severity of kidney disease (low risk, moderately increased risk. high risk, and very high risk) using the combination of eGFR and albuminuria levels. Results: Among men aged 50 years and with eGFR ≥60 mL/min/1.73 m 2 , estimated life expectancy was 24.8 (95% CI: 24.6–25.0), 17.5 (95% CI: 17.1–17.9), and 13.5 (95% CI: 12.6–14.3) years for participants with normal, mild and heavy albuminuria respectively. Life expectancy for men with mild and heavy albuminuria was 7.3 (95% CI: 6.9–7.8) and 11.3 (95% CI: 10.5–12.2) years shorter than men with normal proteinuria, respectively. A reduction in life expectancy was associated with an increasing severity of kidney disease; 24.8 years for low risk (95% CI: 24.6–25.0), 19.1 years for moderately increased risk (95% CI: 18.7–19.5), 14.2 years for high risk (95% CI: 13.5–15.0), and 9.6 years for very high risk (95% CI: 8.4–10.8). Among women of similar age and kidney function, estimated life expectancy was 28.9 (95% CI: 28.7–29.1), 19.8 (95% CI: 19.2–20.3), and 14.8 (95% CI: 13.5–16.0) years for participants with normal, mild and heavy albuminuria respectively. Life expectancy for women with mild and heavy albuminuria was 9.1 (95% CI: 8.5–9.7) and 14.2 (95% CI: 12.9–15.4) years shorter than the women with normal proteinuria, respectively. For women also a graded reduction in life expectancy was observed across the increasing severity of kidney disease; 28.9 years for low risk (95% CI: 28.7–29.1), 22.5 years for moderately increased risk (95% CI: 22.0–22.9), 16.5 years for high risk (95% CI: 15.4–17.5), and 9.2 years for very high risk (95% CI: 7.8–10.7). Limitations: Possible misclassification of long-term kidney function categories cannot be eliminated. Possibility of confounding due to concomitant comorbidities cannot be ruled out. Conclusion: The presence and degree of albuminuria was associated with lower estimated life expectancy for both gender and was especially notable in those with eGFR ≥30 mL/min/1.73 m 2 . Life expectancy associated with a given level of eGFR differs substantially based on the presence and severity of albuminuria

Renal outcome in patients with congenital anomalies of the kidney and urinary tract.

15openopenSanna-Cherchi S; Ravani P; Corbani V; Parodi S; Haupt R; Piaggio G; Innocenti ML; Somenzi D; Trivelli A; Caridi G; Izzi C; Scolari F; Mattioli G; Allegri L; Ghiggeri GM.Sanna Cherchi, S; Ravani, P; Corbani, V; Parodi, S; Haupt, R; Piaggio, G; Innocenti, Ml; Somenzi, D; Trivelli, A; Caridi, G; Izzi, C; Scolari, Francesco; Mattioli, G; Allegri, L; Ghiggeri, G. M

Estimating the effect of referral for nephrology care on the survival of adults with advanced chronic kidney disease in a real-world clinical setting

Introduction Longitudinal studies ascertain exposure, covariates, and outcomes over time. For estimating treatment effect on mortality, ignoring the time-varying nature of an exposure may lead to immortal time bias. Time-dependent confounding that affects future treatment may bias the estimated effects. Differences in baseline prognosis between treatment groups further complicate this issue. Objectives and Approach We applied sequential Cox modeling to estimate the causal effect of referral for nephrology care on the survival of adults with advanced chronic kidney disease, linking laboratory and administrative data from Alberta, Canada. We created pseudo-data by mimicking successive randomized controlled trials. To address immortal time bias, each “mini-trial” consisted of individuals starting treatment, and those not yet treated, in each 3-month time interval. We incorporated inverse-probability-of-treatment-weights (IPTW) to minimize treatment selection bias for each “mini-trial. ” We fit a “mini-trial”-stratified, weighted Cox model to estimate the overall hazard ratio for death by averaging the effect estimates across “mini-trials.” Results We included 9,675 patients who entered the cohort between 2002 and 2013. The mean age was 82 years; 35% were male; and 33% were ultimately referred to a nephrologist after a median wait-period of 6 months. Compared to non-referred patients, those referred were younger and had fewer comorbidities at baseline. Referral was associated with a significant 45% lower hazard for death in an adjusted Cox model. The effect was attenuated in a multivariate Cox model with a time-varying exposure and in a sequential Cox model further controlling for potential time-dependent confounding by measures reflecting kidney-, cardiovascular-, and cerebrovascular-health. After incorporating IPTW for addressing treatment selection bias in the same sequential Cox model, the effect estimate was toward the null and no longer significant. Conclusion/Implications We found that applying analytical strategies that addressed immortal time bias, time-dependent confounding, and treatment selection bias, the survival benefit associated with nephrology referral was attenuated. Inverse-probability-of treatment weighted sequential Cox approach may be used to address these important biases and confounding that are common in real-world clinical settings