Mechanical and Durability Properties of Hybrid Fiber Reinforced High Performance Concrete using Multiple Mineral Admixtures

A study has been made for the high performance concrete of grade M70, where two mineral admixtures like GGBS and Metakaolin has been used with the two fibers, one B glass fibers and asbestos fibers. If two fibers are used in the concrete then we are call is having a fiber reinforced concrete the asbestos fibers percentage was kept constant of about 0.33% and glass fibers % have been changed from 0.25, 0.75 and 1.0%. The cubes are casted for different water cement ratios which is 0.25,0.30 and 0.35. there cubes are tested for the strength teste and durability zero.

Mesothelioma Malignancy and the Microenvironment: Molecular Mechanisms

Several studies have reported that cellular and soluble components of the tumor microenvironment (TME) play a key role in cancer-initiation and progression. Considering the relevance and the complexity of TME in cancer biology, recent research has focused on the investigation of the TME content, in terms of players and informational exchange. Understanding the crosstalk between tumor and non-tumor cells is crucial to design more beneficial anti-cancer therapeutic strategies. Malignant pleural mesothelioma (MPM) is a complex and heterogenous tumor mainly caused by asbestos exposure with few treatment options and low life expectancy after standard therapy. MPM leukocyte infiltration is rich in macrophages. Given the failure of macrophages to eliminate asbestos fibers, these immune cells accumulate in pleural cavity leading to the establishment of a unique inflammatory environment and to the malignant transformation of mesothelial cells. In this inflammatory landscape, stromal and immune cells play a driven role to support tumor development and progression via a bidirectional communication with tumor cells. Characterization of the MPM microenvironment (MPM-ME) may be useful to understand the complexity of mesothelioma biology, such as to identify new molecular druggable targets, with the aim to improve the outcome of the disease. In this review, we summarize the known evidence about the MPM-ME network, including its prognostic and therapeutic relevance.

Recent progress and perspectives on the mechanisms underlying Asbestos toxicity

Most cases of mesothelioma are known to result from exposure to asbestos fibers in the environment or occupational ambient air. The following questions regarding asbestos toxicity remain partially unanswered: (i) why asbestos entering the alveoli during respiration exerts toxicity in the pleura; and (ii) how asbestos causes mesothelioma, even though human mesothelial cells are easily killed upon exposure to asbestos. As for the latter question, it is now thought that the frustrated phagocytosis of asbestos fibers by macrophages prolongs inflammatory responses and gives rise to a “mutagenic microenvironment” around mesothelial cells, resulting in their malignant transformation. Based on epidemiological and genetic studies, a carcinogenic model has been proposed in which BRCA1-associated protein 1 mutations are able to suppress cell death in mesothelial cells and increase genomic instability in the mutagenic microenvironment. This leads to additional mutations, such as CDKN2A [p16], NF2, TP53, LATS2, and SETD2, which are associated with mesothelioma carcinogenesis. Regarding the former question, the receptors involved in the intracellular uptake of asbestos and the mechanism of transfer of inhaled asbestos from the alveoli to the pleura are yet to be elucidated. Further studies using live-cell imaging techniques will be critical to fully understanding the mechanisms underlying asbestos toxicity.

POTENTIAL SOURCES OF AIR POLLUTION BY INDUSTRIAL FIBERS

Resume. Currently almost no attention is paid to the potential possibility of air pollution of premises for various purposes by industrial fibers (natural (asbestos) and man-made mineral fibers) in the Russian Federation while there is increasing use of materials containing such fibers in industrial and civil construction. Purpose. To conduct a survey of premises for various purposes to identify materials containing industrial fibers and assess the potential possibility of releasing fibers from them using research methods adopted in modern world practice. Materials and methods. A visual and instrumental survey of premises was carried out; 169 materials samples, 57 dust samples and 45 air samples were sampled and analyzed. Results. The numerical fiber concentrations in air samples did not exceed the standarts for working area air (0.2 f/ml for man-made mineral fibers (MMMF) and 0.01 f/ml for asbestos fibers), used in modern world practice. MMMF were detected in half of the dust samples, chrysotile asbestos fibers (CAF) were detected in 3 dust samples, MMMF together with CAF were detected in 9 dust samples. CAF were presented in 85 of 169 materials samples, MMVF were presented in 34 materials samples, organic fiber were presented in 18 materials samples, no fibers were presented in 32 materials samples. When using the algorithm for estimating the probability of fiber releasing, 43 materials containing CAF had a very low chance of fiber releasing, 18 – low, 21 – medium, and 3 – high chance, and 15 materials containing MMVF had a very low chance of fiber releasing, 11 – low, 7 – medium, 1 – high. Conclusion. Materials containing industrial fibers are widely used in premises for various purposes. Visual and instrumental survey allows detecting such materials and assessing their condition for the development of measures set to control working area air pollution. The detection of fibers in dust samples makes it possible to establish the presence of sources of air pollution, as well as to identify them in most cases.

CHRYSOTILE-RELATED ASBESTOSIS IN THE POST-EXPOSURE PERIOD. STUDY DESIGN AND PRELIMINARY RESULTS

Abstract. A retrospective case-control study among former workers of PJSC Uralasbest has been launched to establish the main clinical features of the disease as well as causes and structure of mortality in patients with chrysotile-related asbestosis in the post-exposure period taking into cumulative dust exposure. First, we collected information about 850 asbestosis cases diagnosed in the Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers in 1946-2000. Control group of workers without asbestosis, matched by sex, duration of work, working conditions, cumulative dust exposure, social and living conditions, was set up as a control group. All primary information was entered in a specially developed database. Second, we established the vital status of the cases and the controls as of January 1, 2020. A considerable improvement of working conditions for the main jobs at PJSC Uralasbest in the second half of the 20th century leading to a statistically significant decrease in the cumulative exposure both by total dust and respirable chrysotile asbestos fibers. Improved working conditions have influenced increasing the duration of work until the development of the disease as shown by the rise in the proportion of workers with diagnosed asbestosis, mainly stage I, workers with 20 or more years after the first exposure.

COMPARATIVE EVALUATION OF THE CAUSES OF DEATH IN A COHORT OF WORKERS IN THE MINING AND ENRICHMENT OF CHRYSOTILE ASBESTOS

A retrospective cohort study was carried out to investigate the mortality of workers occupationally exposed to dust containing chrysotile asbestos fibers. In its chemical and physical properties, it differs from the fibers of other types of asbestos and is the only type of asbestos that is currently approved for use in many countries of the world. The members of the cohort are current and former employees who have worked for at least one year at the production sites of the complex of enterprises for the mining and enrichment of chrysotile asbestos (JSC «Uralasbest», Asbest, Sverdlovsk region) in the period from 01.01.1975 to 31.12.2010. Of the 35837 members of the cohort, 12729 (35.5%) people died (2373 of them were malignant neoplasms of various localizations, including 10 mesotheliomas), 18799 (52.5%) were alive at the end of the observation period (2015), and 4309 people (12.0%) were censored by the end of 2015. The mean follow-up period was 21.7 years for men and 25.9 years for women. The average age at death was 59.4 years for men and 66.5 years for women. This paper presents a general comparative evaluation of the causes of death of cohort members. Further processing of data obtained is currently underway.

Hazardous Elements in Asbestos Tremolite from the Basilicata Region, Southern Italy: A First Step

In this paper, we report the quantification of potentially toxic elements (PTEs) hosted into two tremolite asbestos from Episcopia and San Severino Lucano villages (Basilicata region, Southern Italy). Micro X-ray fluorescence and Inductively Coupled Plasma spectroscopy with Optical Emission Spectrometry techniques were used to quantify the concentration of major, minor (Si, Mg, Ca, Al, Fe, Mn) and trace elements (As, Ba, Cd, Co, Cr, Cu, Li, Mo, Ni, Pb, Sb, Sn Sr, Ti, Te, V, W, Zn, Zr), with the aim of providing available data useful for the determination of the asbestos fibers toxicity. Results show that in the two studied samples there exist high concentrations of Fe, Mn, Cr and Ni which could lead to the high toxicity of the mineral fibers. By considering the pseudo-total PTEs amounts in each tremolite asbestos, it is possible to affirm that one of the samples is more enriched in toxic elements than the other one (3572 ppm versus 1384 ppm). These PTEs can represent a source of risk to human health since they may be transported away from the geological outcrops, through asbestos in the air, water and soils and thus encountering the human body.