Post-earthquake fire performance of building structures

The potential of fire event after a strong earthquake is quite high and the damage caused by this fire could be significantly higher as compared to normal fire not accompanied by an earthquake. Thus it is important to know the behavior of structures under such circumstances. Modern buildings are designed to have adequate resistance against an expected level earthquake, and sufficient fire safety, considering these events to occur separately. However, fire following a seismic excitation is not uncommon. After an earthquake the structure may sustain a considerable damage and the fire resistance of the system will be significantly impaired. In this case, the fire performance of the structure will be significantly reduced, and such condition may pose a serious threat to structural integrity, which is detrimental to the life safety of the occupants and rescue workers. Thus, it is necessary to consider such scenarios in the design of a building constructed in a seismic zone. In this study the performance of two types of structures has been studied. Load bearing wood stud walls and moment resistant steel frames under such condition has been modeled and analyzed. The performance analysis of the wood stud wall in fire has been verified with the results from the NRC fire tests. For the steel frames, the results are validated with different finite element systems such as SAFIR and ANSYS. The analysis includes heat transfer analysis and thermal stress analysis by using numerical model for wood wall and finite element solver for steel frame. Existing numerical model for stability analysis of wood frame walls cannot be applied to cases with fire and earthquake induced fire. Modifications are proposed to the existing methods in order to account for the time dependent changes in strength, stiffness and geometry due to earthquake and fire in order to determine the fire resistance of the structures. Two analytical approaches have been proposed for modeling the damage in the steel structure after earthquake. Fire resistance rates are investigated for both normal and post earthquake fire scenarios. It is observed from the study that the fire followed by an earthquake reduces the fire resistance of a structure in both wood-frame and steel-frame structures. The study presented here forms a preliminary understanding of the PEF phenomenon and its effect on structures. Further studies are needed to enhance the understanding, quantify the parametric changes and formulate design guidelines to account for PEF hazard to structures in seismic zones. Keywords. post-earthquake fire hazards, conflagration, performance-based design, structural strengthening, monitoring, simulation

Nonlinear seismic soil-pile interaction analysis for bridges founded in Quebec soil

This doctorate program focuses on the nonlinear behavior of seismic soil-structure interaction of deep foundations with particular emphasis in Quebec soil. Soil-structure interaction (SSI) plays a crucial role when analyzing and designing important or essential structures, such as skyscrapers, nuclear reactor facilities and highway bridges. For the latter, deep foundations are commonly used to support the bridge superstructure. Historically, the analysis of the interaction between the piles and the embedment soil under lateral loadings used the beam on Winkler theory which is implemented through the p-y curves general method. The commonly-used springs are driven originally from full-scale tests on piles with static or slow cyclic lateral load application. Evidences, from disturbed or damaged structures after earthquake, indicate that SSI follows different curve from the static p-y curve used in the design. The main objective of this research study is to contribute bridge the gap by carrying comprehensive nonlinear seismic analyses on soil-pile interaction for Quebec soils. Extensive numerical investigations have been conducted on 600 parametrical models in order to evaluate these variations and gaps. Results from this research study shows that the following parameters have a direct impact on the seismic soil-pile interaction: the length of the pile, the mass of the structure, as well as the intensity of the seismic record. The seismic soil-pile interaction (SPSI) is normally investigated by dynamic time history analysis on continuum soil-structure models. However, this process is long and time consuming particularly in engineering practice. A new simplified method is proposed in this study to scale the static p-y curves in order to simulate the dynamic behavior of SPSI. The results indicate a reasonable matching between the results from time-history and static analysis. Scaling the current p-y curves in order to simulate the SPSI, would results in a more accurate estimation for the seismic demands on the bridge. Furthermore it will reduce the computation cost by benefiting from currently-used and fast to implement p-y curve method. Field experiments on several types of soil are recommended in order to normalize these findings for engineering practice

Novel heterocyclic derivatives of pyrano[3,2-c]quinolinone from 3-(1-ethy1-4-hydroxy-2-oxo-2(1H)-quinolin-3-yl)-3-oxopropanoic acid

3-(1-Ethyl-4-hydroxy-2-oxo-2(1H)-quinolin-3-yl)-3-oxopropanoic acid (2) has been synthesized. The chemical behaviour of β-ketoacid 2 was studied towards condensation reactions with salicylaldelyde, 2-hydroxy-1-naphthaldehyde, 1-phenyl-4-hydroxy-2-oxo-quinoline-3-carboxaldehyde, 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxalde-hyde, 2-amino-3-formylchromone and its 8-allyl analog, 3-cyanochromone and its 8-allyl analog. Structures of the newly synthesized products have been deduced from their elemental analysis and spectral data

Optimizing the Thermal Resistance of Concrete Using The Palm Tree Fronds Fibers

In the past few years, the issue of global warming has become increasingly visible. Record high as well as record low temperatures are being broken worldwide. Snow is melting in the poles and less sunrays are being reflected causing more temperature to be absorbed by Earth. One of the main reasons of global warming is burning the fossil fuels for producing electrical energy. One of the household items that consumes a lot of electricity is the air conditioner. In the U.S. alone, it is estimated that every airconditioned house produces two tons of carbon dioxide every year. It is believed that if better insulation systems are used in our houses, especially in the GCC area, the use of air conditioners can be optimized to consume less electricity. The main aim of this project is to come up with an environmentally friendly building insulation system that reduces the electrical consumption used in air conditioners in our houses. PTF was prepared and used as a natural free resource that is available locally in the GCC. Several mixes with different PTF ratios have been prepared and tested for thermal insulation and structural integrity. The results indicate a significant improvement in the R value of concrete. This additive also affected the compressive strength of concrete. It was found that replacing of fine aggregate with less than 1% of PTF will increase the R value of concrete without affecting the strength capacity significantly

Stereotactic Body Radiotherapy in Bulky Hepatocellular Carcinoma with or without Portal Vein Thrombosis: A Feasibility Review in an Egyptian Cohort

Background: Hepatocellular carcinoma (HCC) complicated by portal vein thrombosis presents significant clinical challenges. This study aims to retrospectively assess the feasibility of stereotactic irradiation for treating bulky HCC, with or without vascular invasion. Method: In this retrospective analysis, the radiotherapy treatment plans and clinical follow-up data of 22 patients diagnosed with HCC, with or without portal vein thrombosis, were reviewed. These patients underwent stereotactic body radiation therapy (SBRT) between September 2019 and September 2022. Treatment involved administering 40-50 Gy in 5 fractions using SBRT with volumetric modulated arc therapy (VMAT)/4D-computed tomography. Descriptive statistics were utilized without the application of statistical tests. Results: The mean age of the patients was 65 years, with 77% being male. Portal vein thrombosis was present in 73% of the cases, and the average tumor size was 7.2 cm (range 5-12 cm). 59% of patients were classified as Child-Pugh B. The median follow-up duration was 8 months (range 3-36 months). At 3 months, tumor response assessments revealed that 59% of patients had a partial response and 41% had stable disease; by 6 months, 37% achieved complete response, 26% maintained a partial response, and 37% had stable condition. Failure patterns included intrahepatic failure in two patients (at 7 and 9 months) and extrahepatic loss in two others (at 6 and 10 months). Radiation-induced liver disease occurred in two patients at 9- and 11-weeks post-treatment, respectively. Liver cancer-specific mortality was 13.6%, while non-liver cancer-specific mortality stood at 9%. The progression-free survival rate was 82%. Conclusion: SBRT via VMAT represents a highly cost-effective, non-invasive local therapy with a favorable therapeutic ratio for treating bulky HCC cases, with or without vascular invasion

Metal-Bound Methisazone; Novel Drugs Targeting Prophylaxis and Treatment of SARS-CoV-2, a Molecular Docking Study.

SARS-CoV-2 currently lacks effective first-line drug treatment. We present promising data from in silico docking studies of new Methisazone compounds (modified with calcium, Ca; iron, Fe; magnesium, Mg; manganese, Mn; or zinc, Zn) designed to bind more strongly to key proteins involved in replication of SARS-CoV-2. In this in silico molecular docking study, we investigated the inhibiting role of Methisazone and the modified drugs against SARS-CoV-2 proteins: ribonucleic acid (RNA)-dependent RNA polymerase (RdRp), spike protein, papain-like protease (PlPr), and main protease (MPro). We found that the highest binding interactions were found with the spike protein (6VYB), with the highest overall binding being observed with Mn-bound Methisazone at -8.3 kcal/mol, followed by Zn and Ca at -8.0 kcal/mol, and Fe and Mg at -7.9 kcal/mol. We also found that the metal-modified Methisazone had higher affinity for PlPr and MPro. In addition, we identified multiple binding pockets that could be singly or multiply occupied on all proteins tested. The best binding energy was with Mn-Methisazone versus spike protein, and the largest cumulative increases in binding energies were found with PlPr. We suggest that further studies are warranted to identify whether these compounds may be effective for treatment and/or prophylaxis

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Sex difference and intra-operative tidal volume: Insights from the LAS VEGAS study

BACKGROUND: One key element of lung-protective ventilation is the use of a low tidal volume (VT). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients.OBJECTIVES: The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if present what factors drive this difference.DESIGN, PATIENTS AND SETTING: This is a posthoc analysis of LAS VEGAS, a 1-week worldwide observational study in adults requiring intra-operative ventilation during general anaesthesia for surgery in 146 hospitals in 29 countries.MAIN OUTCOME MEASURES: Women and men were compared with respect to use of LTVV, defined as VT of 8 ml kg-1 or less predicted bodyweight (PBW). A VT was deemed 'default' if the set VT was a round number. A mediation analysis assessed which factors may explain the sex difference in use of LTVV during intra-operative ventilation.RESULTS: This analysis includes 9864 patients, of whom 5425 (55%) were women. A default VT was often set, both in women and men; mode VT was 500 ml. Median [IQR] VT was higher in women than in men (8.6 [7.7 to 9.6] vs. 7.6 [6.8 to 8.4] ml kg-1 PBW, P < 0.001). Compared with men, women were twice as likely not to receive LTVV [68.8 vs. 36.0%; relative risk ratio 2.1 (95% CI 1.9 to 2.1), P < 0.001]. In the mediation analysis, patients' height and actual body weight (ABW) explained 81 and 18% of the sex difference in use of LTVV, respectively; it was not explained by the use of a default VT.CONCLUSION: In this worldwide cohort of patients receiving intra-operative ventilation during general anaesthesia for surgery, women received a higher VT than men during intra-operative ventilation. The risk for a female not to receive LTVV during surgery was double that of males. Height and ABW were the two mediators of the sex difference in use of LTVV.TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov, NCT01601223

PANC Study (Pancreatitis: A National Cohort Study): national cohort study examining the first 30 days from presentation of acute pancreatitis in the UK

Abstract Background Acute pancreatitis is a common, yet complex, emergency surgical presentation. Multiple guidelines exist and management can vary significantly. The aim of this first UK, multicentre, prospective cohort study was to assess the variation in management of acute pancreatitis to guide resource planning and optimize treatment. Methods All patients aged greater than or equal to 18 years presenting with acute pancreatitis, as per the Atlanta criteria, from March to April 2021 were eligible for inclusion and followed up for 30 days. Anonymized data were uploaded to a secure electronic database in line with local governance approvals. Results A total of 113 hospitals contributed data on 2580 patients, with an equal sex distribution and a mean age of 57 years. The aetiology was gallstones in 50.6 per cent, with idiopathic the next most common (22.4 per cent). In addition to the 7.6 per cent with a diagnosis of chronic pancreatitis, 20.1 per cent of patients had a previous episode of acute pancreatitis. One in 20 patients were classed as having severe pancreatitis, as per the Atlanta criteria. The overall mortality rate was 2.3 per cent at 30 days, but rose to one in three in the severe group. Predictors of death included male sex, increased age, and frailty; previous acute pancreatitis and gallstones as aetiologies were protective. Smoking status and body mass index did not affect death. Conclusion Most patients presenting with acute pancreatitis have a mild, self-limiting disease. Rates of patients with idiopathic pancreatitis are high. Recurrent attacks of pancreatitis are common, but are likely to have reduced risk of death on subsequent admissions. </jats:sec

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries