Lateral-torsional buckling of unrestrained steel beams under fire conditions: Improvement of EC3 proposal

The final draft of the EN version of part 1.1 of Eurocode 3 has introduced significant changes in the evaluation of the lateral-torsional buckling resistance of unrestrained beams at room temperature that reduce the over-conservative approach of ENV 1993-1-1 in the case of non-uniform bending. Numerical modelling of the lateral-torsional buckling of steel beams at elevated temperature has shown that the beam design curve from prEN 1993-1-2 is over-conservative for loadings other than uniform bending. In line with the safety format of the lateral-torsional buckling code provisions for cold design, an alternative proposal for rolled sections or equivalent welded sections subjected to fire is presented in this paper, that addresses the issue of the influence of the loading type on the resistance of the beam, achieving better agreement with the real behaviour while maintaining safety. (C) 2004 Elsevier Ltd. All rights reserved

Numerical study of steel beams in sub-frame assembly, Validation of existing hand calculation procedures

The design methods currently proposed by the codes prescribe the strength assessment of structures to be based on their strength limit state. These design methods can be applied to isolated steel members to determine their design strength in fire. The real response of a structural member is, however, more complex due to the thermal expansion and the presence of restraints against this expansion by the surrounding structure. It is therefore imperative to study the response of a structural member at high temperature in a way which includes its interaction with its surroundings. This paper will focus on the numerical investigation of steel beams in structural frames connected to concrete filled tubular (CFT) columns through reverse channel connections and comparison to hand calculation procedures

Características da angioarquitetura do testículo de cobaios

The branches of the testicular artery in guinea pig were a main capsular artery and some capsular branches with oblique-longitudinal and transverse-longitudinal dispositions, and variable patterns at the lateral and medial surfaces of the testes. Subcapsular branches arose through the proper testicular artery or by the capsular artery and the subcapsular branches emitted: the extralbuginic blood vessels placed between the mesothelium layer and the proper dense albuginea layer of the testis capsule, the intralbuginic vascular vessels characterised by presence of arterial and venous segments inside the myostromal structure of the testis albuginea and the subcapsular and intratesticular sequential vessels which appeared as small arteries and veins, arterioles and venules and capillaries of the capillary trees. The last vessels, mainly the arterioles, venules and capillaries of the testis showed a complex pattern of disposition, in which was viewed parallel and perpendicular vessels concerning to the spatial orientation of the seminiferous tubules.Os ramos da artéria testicular em cobaio são uma artéria capsular principal e alguns ramos capsulares com disposições oblíqua-longitudinal e transversa-longitudinal, mostrando um padrão distributivo variável em ambas as superfícies dos testículos. Os ramos subcapsulares se originam da própria artéria testicular ou da artéria capsular, sendo que estes ramos subcapsulares emitem vários outros ramos com disposição estratigrafica variável. Assim, se notam vasos sanguíneos extraalbugínicos colocados entre o estrato mesotelial e o próprio estrato denso da albugínea. Os vasos intra-albugínicos são caracterizados como seguimentos arteriasis e venosos dispostos na intimidade da albugínea testicular. Os vasos subcapsulares e intratesticulares sequentes aos anteriores aparecem na intimidade do testículo como pequenas artérias e veias, arteríolas e vênulas e capilares das redes capilares. Os vasos intratesticulares mostram um padrão complexo de disposição, sendo vistos, especialmente os capilares, com orientação espacial paralela ou perpendicular em relação aos túbulos seminíferos os quais circundam

Discrimination of hydrologic variations for spatial distribution of fish assemblage in a large subtropical temperate river

This study examines the effects of the flow and flood pulses on spatialdispersion of fish assemblages in the floodplain of the Paraná River in Argentina. Wetested the hypothesis that high water levels and greater lateral connectivity promotefish dispersal and spatial homogenization of assemblage structure. We sampled foursites during different phases of the annual hydrologic cycle from 2010 to 2016. Watersurface in the area was estimated during each phase. We computed multivariatestatistics and estimates of ß-diversity to analyze assemblage variations in relation tohydrological phases. Three hydrological phases were defined: low flow pulses (waterlevels between 2.3 and 3.2, approximately 10% of the floodplain covered by water),high flow pulses(between 3.2 and 4.5, from 11 to 84%), and floods (> 4.5 m, morethan 84%). Although difference between high flow pulses and flood was notsignificant, ß-diversity values for these stages were higher than for low flow pulses.This suggests that floods and high flow pulses increase the spatial variability of fishassemblages, whereas homogenization processes occur later during low flowperiods. This work provides further knowledge about the flood homogenization effectin a large unregulated floodplain where lateral connectivity still plays a significant roleon ecological structuring processes.Fil: Espínola, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Abrial, Elie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Rabuffetti, Ana Pia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Simoes Da Silva, Nadson Ressyé. Universidade Federal Do Sul Da Bahia. Centro de Formação Em Ciências Ambientais.; BrasilFil: Amsler, Mario Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Blettler, Martin Cesar Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Eurich, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Paira, Aldo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Statistical analysis of fatigue crack propagation data of materials from ancient portuguese metallic bridges

In Portugal there is a number of old metallic riveted railway and highway bridges that were erected by the end of the 19th century and beginning of the 20th century, and are still in operation, requiring inspections and remediation measures to overcome fatigue damage. Residual fatigue life predictions should be based on actual fatigue data from bridge materials which is scarce due to the material specificities. Fatigue crack propagation data of materials from representative Portuguese riveted bridges, namely the Pinhão and Luiz I road bridges, the Viana road/railway bridge, the Fão road bridge and the Trezói railway bridge were considered in this study. The fatigue crack growth rates were correlated using the Paris’s law. Also, a statistical analysis of the pure mode I fatigue crack growth (FCG) data available for the materials from the ancient riveted metallic bridges is presented. Based on this analysis, design FCG curves are proposed and compared with BS7910 standard proposal, for the Paris region, which is one important fatigue regime concerning the application of the Fracture Mechanics approaches, to predict the remnant fatigue life of structural details

α-actinin accounts for the bioactivity of actin preparations in inducing STAT target genes in

Damage-associated molecular patterns (DAMPs) are molecules exposed or released by dead cells that trigger or modulate immunity and tissue repair. In vertebrates, the cytoskeletal component F-actin is a DAMP specifically recognised by DNGR-1, an innate immune receptor. Previously we suggested that actin is also a DAMP in Drosophila melanogaster by inducing STATdependent genes (Srinivasan et al., 2016). Here, we revise that conclusion and report that aactinin is far more potent than actin at inducing the same STAT response and can be found in trace amounts in actin preparations. Recombinant expression of actin or a-actinin in bacteria demonstrated that only a-actinin could drive the expression of STAT target genes in Drosophila. The response to injected a-actinin required the same signalling cascade that we had identified in our previous work using actin preparations. Taken together, these data indicate that a-actinin rather than actin drives STAT activation when injected into Drosophila

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112