Application of Pre-fabricated Concrete Elements (PCE) in construction projects in Iran

Abstract: In recent decades, construction waste has become a serious environmental problem in many large cities around the globe. The construction sector in Tehran/Iran produced 50,000 tonnes of waste each day in 2010. Furthermore the growing young population, changing lifestyles and rising demand for housing increases the construction material consumption, hence generating more waste. Two main materials are used to construct buildings in Iran: steel and concrete. Various studies have exposed that use of PCE significantly decrease in the amount of waste production. This study aims to explore advantages, barriers, and potential improvement activities on PCE in Iran based on interviews and a questionnaire survey. Moreover, the three methods of concrete construction that are used in the Iranian, namely in-situ concrete, ready-mixed concrete and PCE have been examined. A case study in Tehran was used to illustrate the concrete waste generation and financial issues of these three concrete work methods. The results of questionnaires illustrate that the main advantages of applying PCE in Iran areon-site concrete waste reduction; improve environmental performance; and shorten project time. Moreover, the most significant hindrances are higher project costs; lack of legislation and regulations; limited manufacturers; and limited products. The findingsof the case study indicate that use of PCE has the most cost and the least on-site concrete waste than the other two methods. Finally, the most mentioned recommendation for improving use of PCE in Iran were governmental incentives for using PCE; and education and training

Association of IL-12B rs3212227 and IL-6 rs1800795 polymorphisms with susceptibility to cervical cancer: A systematic review and meta-analysis

Background: Primary studies have shown that the IL-12B rs3212227 and IL-6 rs1800795 polymorphisms are associated with an increased risk of cervical cancer. However, conflicting results warrant a meta-analysis to obtain more precise estimates. Methods: A comprehensive literate search on PubMed, Web of Science, Scopus, CNKI, and SciELO was performed to collect all eligible studies up to November 10, 2019. The pooled odds ratios (OR) and 95 confidence intervals (CI) were used to calculate the risk. This meta-analysis was carried out by utilizing CMA software. Results: A total of eleven case-control studies including four studies on IL-12B rs3212227 and seven studies on IL-6 rs1800795 were selected. Pooled ORs revealed that the IL-6 rs1800795 polymorphism was significantly associated with an increased risk of cervical cancer (C vs. G: OR = 1.294, 95 CI 1.071-1.564, p= 0.007; CC vs. GG: OR = 1.633, 95 CI 1.059-2.520, p= 0.027; CC+CG vs. GG: OR = 1.312, 95 CI 1.048-1.643, p= 0.018; and CC vs. CG+GG: OR = 1.592, 95 CI 1.268-1.999, p�0.001), but not IL-12B rs3212227 polymorphism. Stratified analysis by ethnicity revealed that both IL-12B rs3212227 and IL-6 rs1800795 polymorphisms were associated with risk of cervical cancer in Asian women. Conclusions: Our pooled data revealed that the IL-12B rs3212227 and IL-6 rs1800795 polymorphisms may be used to identify individuals at high risk of cervical cancer in Asian women. © 2020, Asian Pacific Organization for Cancer Prevention

The association of tobacco smoking and bone health in the elderly population of Iran: results from Bushehr elderly health (BEH) program

Smoking has been linked with osteoporosis, but further evidence is required, especially concerning the effects of different types of tobacco smoking. We sought to examine the association between smoking and bone health in a large cohort of elderly Iranians. Methods: The data from 2377 participants aged >60 years of Bushehr Elderly Health (BEH) program were used. Regardless of the type of smoking, participants were initially classified as non-smokers, ex-smokers and current smokers. Current smokers were also categorized based on the smoking type (pure cigarette, pure hookah and both). Dual-energy X-ray absorptiometry was used to evaluate bone density as well as Trabecular Bone Score (TBS). T-score ≤ −2.5 in either of the femoral neck, total hip or spinal sites was applied to determine the osteoporosis. The association of smoking and osteoporosis was assessed using multivariable modified Poisson regression model and reported as adjusted prevalence ratios (APR). The linear regression model was used to assess the association between smoking and TBS, adjusting for potential factors. Results: A total of 2377 (1225 women) were enrolled [mean age: 69.3 (±6.4) years], among which 1054 (44.3%) participants were nonsmokers. In all, 496 (20.9%) participants were current smokers. Multivariable regression analysis revealed no significant association between smoking (either current or past) and osteoporosis in women. In men, current smoking was negatively associated with osteoporosis (APR: 1.51, 95%CI: 1.16–1.96). Among current users, cigarette smoking was associated with osteoporosis (APR: 1.57, 95%CI: 1.20–2.03); however, we could not detect a significant association between current smoking of hookah and osteoporosis. In men, a significant association was also detected between current cigarette smoking and TBS (coefficient: -0.03, 95%CI: −0.01, −0.04). Conclusion: Current cigarette smoking is associated with both the quantity and quality of bone mass in elderly men. Although we could not detect a significant association between hookah and osteoporosis in men, considering the prevalence of hookah smoking in the middle eastern countries, further studies are needed to determine the effect of hookah smoking on bone health

Review of thermo-physical properties, wetting and heat transfer characteristics of nanofluids and their applicability in industrial quench heat treatment

The success of quenching process during industrial heat treatment mainly depends on the heat transfer characteristics of the quenching medium. In the case of quenching, the scope for redesigning the system or operational parameters for enhancing the heat transfer is very much limited and the emphasis should be on designing quench media with enhanced heat transfer characteristics. Recent studies on nanofluids have shown that these fluids offer improved wetting and heat transfer characteristics. Further water-based nanofluids are environment friendly as compared to mineral oil quench media. These potential advantages have led to the development of nanofluid-based quench media for heat treatment practices. In this article, thermo-physical properties, wetting and boiling heat transfer characteristics of nanofluids are reviewed and discussed. The unique thermal and heat transfer characteristics of nanofluids would be extremely useful for exploiting them as quench media for industrial heat treatment

Association of MTHFR 677C>T polymorphism with IUGR and placental abruption risk: A systematic review and meta-analysis

Objective: The effects of the MTHFR 677C > T polymorphism on the intrauterine growth restriction (IUGR) and placental abruption risk have been evaluated in some studies. However, those studies results were conflicting and ambiguous. Therefore, we carried out the current meta-analysis to evaluate the association of MTHFR 677C > T polymorphism with risk of IUGR and placental abruption from all eligible studies. Methods: An electronic search of the PubMed, Embase, Scopus and CNKI databases was performed up to February 25, 2020. Results: A total of 25 case-control studies including eight studies with 687 cases and 2336 controls for IUGR and 17 studies with 1574 cases and 5758 controls for placental abruption were selected. The analysis results indicated that MTHFR 677C > T polymorphism was associated with an increased risk of IUGR and placental abruption in global population. When stratified by ethnicity a significant association between the MTHFR 677C > T polymorphism and IUGR risk was found in Caucasians and Africans. However, there was no a significant association between the MTHFR 677C > T polymorphism and placental abruption risk by ethnicity. Conclusions: Our pooled data indicated that the MTHFR 677C > T polymorphism might play a role in development of IUGR and placental abruption. © 2020 Elsevier B.V