Effect of elevated temperature on mechanical properties of normal strength concrete: An overview

Concrete is frequently used in construction owing to its advantageous mechanical characteristics, including its high compressive strength, durability, workability, and fire resistance. Nevertheless, sustained exposure to fire can result in these qualities deteriorating, which poses a serious risk to concrete buildings. As a result, it is critical that researchers investigate how exposure to fire affects the mechanical characteristics of concrete in order to address this problem. Temperature, environmental conditions, the composition of the concrete mixture, and other factors all have an impact on the thermal and mechanical characteristics of concrete. This work seeks to give an overview of how exposure to fire affects the mechanical characteristics of concrete and to highlight areas that require further research. According to the study, there are three main stages that normal concrete strength goes through. The first stage sees a slight increase in strength between 20 and 300°Celsius, followed by a sharp decrease between 300 and 800°Celsius, and finally a complete loss of strength above 800°. Moreover, the fire response of concrete is strongly influenced by factors including the kind of aggregate, moisture content, concrete grade, additives, heating rate, and heating time. By making optimal use of admixtures, the fire behavior can be significantly improved

Prevalence of genetic polymorphisms in the promoter region of the alpha-1 antitrypsin (SERPINA1) gene in chronic liver disease: a case control study

Contains fulltext : 89639.pdf (publisher's version ) (Open Access)BACKGROUND: Alpha-1 antitrypsin (A1AT) deficiency, caused by the Z allele (p.E342K) and S allele (p.E264V) in the SERPINA1 gene, can induce liver and pulmonary disease. Different mechanisms appear to be responsible for the pathogenesis of these divergent disease expressions. The c.-1973T >C polymorphism located in the SERPINA1 promoter region is found more frequent in A1AT deficiency patients with liver disease compared to patients with pulmonary disease, but data are lacking regarding contribution to the development of liver diseases caused by other aetiologies. AIM: To study the prevalence of c.-1973T >C, Z allele and S allele in a cohort of patients with liver disease of various aetiologies compared with healthy controls and to evaluate its effect on disease progression. METHODS: A total of 297 patients with liver disease from various aetiologies and 297 age and gender matched healthy controls were included. The c.-1973T >C polymorphism and Z and S alleles of the SERPINA1 gene were analyzed by real-time PCR. RESULTS: c.-1973T >C was similarly distributed between patients with liver disease of various origins and healthy controls. Furthermore, the distribution of c.-1973T >C was independent from aetiology subgroup. In patients with liver disease mean ages at of onset of liver disease were 44.4, 42.3 and 40.7 years for the c.-1973 T/T, T/C and C/C genotype respectively (NS). S allele heterozygosity was increased in patients with drug induced liver injury (DILI), (OR 4.3; 95%CI 1.1-17.2). CONCLUSION: In our study, c.-1973T >C polymorphism was not a risk factor for liver disease of various aetiologies. In addition, S allele heterozygosity might contribute to the development of DILI

Clinical and functional characteristics of individuals with alpha-1 antitrypsin deficiency: EARCO international registry

Background: Alpha-1 antitrypsin deficiency (AATD) is a rare disease that is associated with an increased risk of pulmonary emphysema. The European AATD Research Collaboration (EARCO) international registry was founded with the objective of characterising the individuals with AATD and investigating their natural history.Methods: The EARCO registry is an international, observational and prospective study of individuals with AATD, defined as AAT serum levels1000 individuals with AATD from 15 countries in its first 2 years. Baseline cross sectional data provide relevant information about the clinical phenotypes of the disease, the patterns of functional impairment and factors associated with poor lung function.Pathogenesis and treatment of chronic pulmonary disease

Lung transplantation and survival outcomes in patients with oxygen-dependent COPD with regard to their alpha-1 antitrypsin deficiency status

Magnus Ekström, Hanan Tanash Department of Respiratory Medicine and Allergology, Skåne University Hospital, Lund University, Lund, Sweden Background: Individuals with severe alpha-1 antitrypsin deficiency (AATD) have an increased risk of developing COPD. However, outcomes during long-term oxygen therapy (LTOT) in patients with severe AATD and hypoxemia are unknown.Patients and methods: This was a prospective, population-based, consecutive cohort study of patients on LTOT due to COPD in the period from January 1, 1987, to June 30, 2015, in the Swedish National Registry for Respiratory Failure (Swedevox). Severe AATD was identified using the Swedish AATD registry and confirmed by isoelectric focusing. Data on lung transplantation (LTx) were obtained from the two lung transplantation centers in Sweden. Mortality and causes of death were assessed based on the National Causes of Death Registry and analyzed using multivariable Cox regression.Results: A total of 14,644 patients who started LTOT due to COPD were included in this study. No patient was lost to follow up. Patients with AATD were younger, included more males and more never smokers, and had fewer comorbidities. During a median follow-up of 1.6 years (interquartile range [IQR], 2.7) on LTOT, patients without severe AATD had a higher mortality, hazard ratio [HR] 1.53 (95% CI, 1.24–1.88), adjusting for age, sex, smoking status, body mass index, performance status, level of hypoxemia, and comorbidities. Cardiovascular deaths were increased. A higher proportion of AATD patients underwent LTx, 53 (19%) vs 118 (1%). Survival after LTx was similar for AATD and non-AATD patients and was predicted by age.Conclusion: In oxygen-dependent COPD, patients with severe AATD have a longer survival time on LTOT, but they have a similar prognosis after lung transplantation compared with patients without AATD. Keywords: COPD, long-term oxygen therapy, lung transplantation, severe alpha-1 antitrypsin deficiency, surviva

Decline in FEV1 and hospitalized exacerbations in individuals with severe alpha-1 antitrypsin deficiency

Adriana-Maria Hiller,1 Eeva Piitulainen,1 Lars Jehpsson,2 Hanan Tanash11Department of Respiratory Medicine and Allergology, Skåne University Hospital, Lund University, Lund, Sweden; 2Department of Clinical Sciences, Skåne University Hospital, Lund University, Lund, SwedenBackground and aim: The value of the forced expiratory volume in one second (FEV1) is useful in the diagnosis and prognosis of chronic obstructive pulmonary disease (COPD). Previous studies on lung function in individuals with severe alpha-1 antitrypsin deficiency (AATD) have shown a variable annual decline in FEV1 (∆FEV1). The aim of this study was to analyze ∆FEV1 and to identify risk factors for ∆FEV1 in individuals with severe AATD.Material and methods: Data on smoking habits, symptoms, results of lung function tests and exacerbations were obtained from the Swedish AATD Register and the Swedish National Patient Register (SNPR). The ∆FEV1 was analyzed by random-effects modeling and adjusted for age and FEV1 at baseline.Results: One hundred and four (9%) current smokers, 539 (48%) ex-smokers and 489 (43%) never-smokers were included in the study and followed-up from 1991 to 2016. A total of 584 (52%) individuals with severe AATD had COPD at inclusion. The median (IQR) annual severe exacerbation rate was 0.66 (1.4). The adjusted mean ∆FEV1 was significantly higher in the current smokers compared with the ex-smokers and never-smokers (70 [95% CI 56–83] vs 42 [95% CI 36–48] and 32 [95% CI 25–38) mL·yr−1,], in the middle–aged individuals compared with the young individuals (48 [95% CI 41–55] vs 32 [95% CI 18–45] mL·yr−1,), in the individuals with respiratory symptoms at inclusion compared with the asymptomatic individuals (46 [95% CI 40–52] vs 30 [95% CI 22–38]mL·yr−1,), and in the individuals with frequent exacerbations compared with those with infrequent exacerbations (57 [95% CI 47–68] vs 27 [95% CI 17–37] mL·yr−1,).Conclusion: Active smoking, age, respiratory symptoms at baseline and repeated severe exacerbations of COPD are factors associated with an accelerated decline of lung function in individuals with severe AATD.Keywords: alpha-1 antitrypsin, decline, exacerbation, lung function, smokin

Tolerant Fuel for WWER-1200 Reactors with High Thermal Conductivity

The main factor of destruction of fuel rods in accidents with loss of coolant is associated with the vapor-zirconium reaction occurring between the fuel rod shell and the coolant (water). Improving the reliability of fuel cells can be obtained by modifying or replacing the fuel shell, materials that do not interact with the coolant during normal operation and in emergency situations. Increasing the reliability and economic characteristics of nuclear power plants is possible by replacing uranium dioxide with fissile compositions with a high content of fissile isotopes and with greater thermal conductivity. These two provisions form the concept of ATF (tolerant fuel). Variants of creation of tolerant fuel are considered., variants of modernization of shells and fissile compositions are studied for nuclear power plants with WWER reactors.</jats:p

Indications and patterns of use of benzodiazepines and opioids in severe interstitial lung disease: a population-based longitudinal study.

BackgroundDespite evidence that opioids might relieve chronic breathlessness, physicians may still be reluctant to prescribe them due to safety concerns. By contrast, benzodiazepine (BDZ) prescribing often seeks to reduce chronic breathlessness despite no evidence of net benefit. Prescribing patterns and indications for these medications in severe interstitial lung disease (ILD) are unknown. Here, our objective was to evaluate the indications, medications and temporal patterns of BDZ and opioid prescriptions in people with oxygen-dependent ILD.MethodsThis was an observational, population-based, longitudinal study of adults starting long-term oxygen therapy (LTOT) for ILD between 2005 and 2014 in the Swedish National Registry for Respiratory Failure (Swedevox). People dispensed BDZs (n=2000) and opioids (n=2000) from 6 months before start of LTOT throughout follow-up (first of death or study end) were analysed.ResultsOf 1635 included patients, 651 (39.8%) received BDZs and 710 (43.4%) received opioids during the study period; 373 (22.8%) patients received both. The most frequently prescribed BDZs and opioids were oxazepam (85.6%) and oxycodone (28.7%), respectively. Indications for breathlessness were uncommon for BDZs (1.4%) and opioids (6.4%). During the last year of life, opioid indications for breathlessness increased from 2.5% (12-10 months before death) to 10.2% in the last 3 months of life (p=0.048).ConclusionsIn oxygen-dependent ILD, opioids are rarely prescribed for breathlessness even in the last months of life, when chronic breathlessness often increases in prevalence and intensity