185 research outputs found
STR-944: EFFECTS OF FINITE ELEMENT MODELLING APPROACH FOR PRESTRESSING SYSTEM ON THE PRESSURE CAPACITY OF A CANDU CONTAINMENT STRUCTURE
The primary objective of this article is to investigate the response of a CANDU®1 nuclear power plant containment structure to a much higher internal pressure that could be encountered during a severe accident. In this study, for the prestressed containment structure, a detailed model is obtained by a full 3D model. Nonlinear finite element method is employed to predict the response of the structure using ANSYS software. The major challenges for modelling prestressing tendon elements are to accommodate parameters affecting prestressing forces. In previous research studies, the prestressing system is modelled using an equivalent pressure and tendon end forces, and tendons are modelled as smeared reinforcement in the concrete elements. In this study, the prestressing tendons are modelled using discrete elements. This method enables the capability of the model to update the prestressing forces accommodating the non-uniform losses. The difference in the response of the structure using the discrete model for the prestressing tendons and the smeared approach is 15 percent. It is observed that the containment structure, meets the design requirements of the current standards as it behaves linearly up to 1.5 times the design pressure, and the ultimate pressure capacity is estimated as 2.7 times the design pressure. The ultimate pressure capacity is reached when the prestressing tendon rupture at the dome
Structure of a Cell Entry Defective Human Adenovirus Provides Insights into Precursor Proteins and Capsid Maturation : Cryo-EM structure of ts1 virion of an adenovirus
Funding Information: We would like to thank Dr. Francisco Asturias for his advice on electron microscopy experiments and Dr. J.C. Ducom for installing Scipion and cisTEM packages on the HPC cluster and computational support in general. This work was supported by the NIH grant R21 AI146644 to V.S.R. Publisher Copyright: © 2021 Elsevier LtdMaturation of adenoviruses is distinguished by proteolytic processing of several interior minor capsid proteins and core proteins by the adenoviral protease and subsequent reorganization of adenovirus core. We report the results derived from the icosahedrally averaged cryo-EM structure of a cell entry defective form of adenovirus, designated ts1, at a resolution of 3.7 Å as well as of the localized reconstructions of unique hexons and penton base. The virion structure revealed the structures and organization of precursors of minor capsid proteins, pIIIa, pVI and pVIII, which are closely associated with the hexons on the capsid interior. In addition to a well-ordered helical domain (a.a. 310–397) of pIIIa, highlights of the structure include the precursors of VIII display significantly different structures near the cleavage sites. Moreover, we traced residues 4–96 of the membrane lytic protein (pVI) that includes an amphipathic helix occluded deep in the hexon cavity suggesting the possibility of co-assembly of hexons with the precursors of VI. In addition, we observe a second copy of pVI ordered up to residue L40 in the peripentonal hexons and a few fragments of density corresponding to 2nd and 3rd copies of pVI in other hexons. However, we see no evidence of precursors of VII binding in the hexon cavity. These findings suggest the possibility that differently bound pVI molecules undergo processing at the N-terminal cleavage sites at varying efficiencies, subsequently creating competition between the cleaved and uncleaved forms of VI, followed by reorganization, processing, and release of VI molecules from the hexon cavities.Peer reviewe
Machine learning applied to the h index of colombian authors with publications in scopus
Our research aims to establish how to predict the H index of Colombian authors with publications in Scopus until 2016. The selection of the date was because, as mentioned earlier, the number of documents indexed per year exceeded 10,000 and they obtained the highest number of documents cited. To accomplish this purpose, a quantitative, nonexperimental, cross-sectional, descriptive, explanatory, and predictive research was designed using supervised learning algorithms. These were applied to information from 8,840 Colombian authors. Among the findings we can highlight that: (i) Colombia is in the fifth position in the scope of countries of South America and the Caribbean, in terms of the number of products and citations; (ii) the largest number of Colombian authors with products in Scopus until 2016, belonged mainly to the area of natural sciences, followed by medical sciences and health; (iii) most of the Colombian authors were men (64.2%, or 5,442) and they have higher H index rates than women; (iv) using random cross validation for 10 iterations, the methods with the best predictive value using R2 and the minimization of mean absolute error (MAE) correspond to: AdaBoost (96.6% and 0.397, respectively); Random Forest (96.8% and 0.431, respectively); KNN (94.4% and 0.525, respectively); Tree (94.9% and 0.53, respectively); and Neural Network (93.3% and 0.7, respectively); and (v) the variables that help predict the H index in the case of the Colombian authors, in addition to the citations, correspond to: the quantity of products, number of products in Q1, and international collaboratio
Best practice considerations on the assessment of robotic assisted surgical systems:results from an international consensus expert panel
Background Health technology assessments (HTAs) of robotic assisted surgery (RAS) face several challenges in assessing the value of robotic surgical platforms. As a result of using different assessment methods, previous HTAs have reached different conclusions when evaluating RAS. While the number of available systems and surgical procedures is rapidly growing, existing frameworks for assessing MedTech provide a starting point, but specific considerations are needed for HTAs of RAS to ensure consistent results. This work aimed to discuss different approaches and produce guidance on evaluating RAS. Methods A consensus conference research methodology was adopted. A panel of 14 experts was assembled with international experience and representing relevant stakeholders: clinicians, health economists, HTA practitioners, policy makers, and industry. A review of previous HTAs was performed and seven key themes were extracted from the literature for consideration. Over five meetings, the panel discussed the key themes and formulated consensus statements. Results A total of ninety-eight previous HTAs were identified from twenty-five total countries. The seven key themes were evidence inclusion and exclusion, patient- and clinician-reported outcomes, the learning curve, allocation of costs, appropriate time horizons, economic analysis methods, and robotic ecosystem/wider benefits. Conclusions Robotic surgical platforms are tools, not therapies. Their value varies according to context and should be considered across therapeutic areas and stakeholders. The principles set out in this paper should help HTA bodies at all levels to evaluate RAS. This work may serve as a case study for rapidly developing areas in MedTech that require particular consideration for HTAs.</p
Minocycline combination therapy with fluvoxamine in moderate-to-severe obsessive�compulsive disorder: A placebo-controlled, double-blind, randomized trial
Aim: Several lines of evidence implicate glutamatergic dysfunction in the pathophysiology of obsessive�compulsive disorder (OCD), presenting this neurotransmitter as a target for the development of novel pharmacotherapy. The objective of this study was to assess the efficacy of minocycline as an augmentative agent to fluvoxamine in the treatment of patients with OCD. Methods: One hundred and two patients with the diagnosis of moderate-to-severe OCD were recruited to this study. A randomized double-blind trial was designed and patients received either L-carnosine or placebo as adjuvant to fluvoxamine for 10 weeks. The patients randomly received either minocycline 100 mg twice per day or placebo for 10 weeks. All patients received fluvoxamine (100 mg/day) for the first 4 weeks, followed by 200 mg/day for the rest of the trial, regardless of their treatment groups. Participants were evaluated using the Yale�Brown Obsessive Compulsive Scale (Y-BOCS). The main outcome measure was to assess the efficacy of minocycline in improving the OCD symptoms. Results: General linear model repeated measures demonstrated significant effect for time � treatment interaction on the Y-BOCS total scores, F(1.49, 137.93) = 7.1, P = 0.003, and Y-BOCS Obsession subscale score, F(1.54, 141.94) = 9.72, P = 0.001, and near significant effect for the Y-BOCS Compulsion subscale score, F(1.27, 117.47) = 2.92, P = 0.08. A significantly greater rate of partial and complete response was observed in the minocycline group (P < 0.001). The frequency of side-effects was not significantly different between the treatment arms. Conclusion: The results of this study suggest that minocycline could be a tolerable and effective adjuvant in the management of patients with OCD. © 2016 The Authors. Psychiatry and Clinical Neurosciences © 2016 Japanese Society of Psychiatry and Neurolog
Possible association of vitamin D status with lung involvement and outcome in patients with COVID-19: a retrospective study
Purpose: Vitamin D deficiency has been reported as a key factor in the development of infectious diseases such as respiratory tract infections and inflammatory processes like acute respiratory distress syndrome. However, the impact of vitamin D on the severity and outcome of COVID-19 is still not fully known. Herein, we aimed to evaluate the prognostic role of serum vitamin D concentration on the extent of lung involvement and final outcome in patients with COVID-19. Methods: Seventy-three subjects with confirmed diagnosis of COVID-19 were investigated in this study. The patients had been admitted to our academic hospital from February 28, 2020 to April 19, 2020. Demographic and clinical data, serum 25(OH)D levels, and findings of initial chest computed tomography were recorded. Linear and binary logistic regression, cox regression and ROC curve tests were used for statistical analysis. Results: The mean age of patients was 55.18 ± 14.98 years old; 46.4 were male. Mean serum 25(OH)D concentration was significantly lower in the deceased (13.83 ± 12.53 ng/ mL compared with discharged patients (38.41 ± 18.51 ng/mL) (P < 0.001). Higher levels of 25(OH)D were associated with significantly less extent of total lung involvement (β = � 0.10, P = 0.004). In addition, vitamin D deficiency 25(OH) D < 25 ng/mL was associated with a significant increase in the risk of mortality (hazard ratio = 4.15, P = 0.04). Conclusion: This study suggests that serum vitamin D status might provide useful information regarding the clinical course, extent of lung involvement and outcome of patients with COVID-19. However, further studies with larger sample size are needed to confirm these findings. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature
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