Exposure from the Chernobyl accident had adverse effects on erythrocytes, leukocytes, and, platelets in children in the Narodichesky region, Ukraine: A 6-year follow-up study

<p>Abstract</p> <p>Background</p> <p>After the Chernobyl nuclear accident on April 26, 1986, all children in the contaminated territory of the Narodichesky region, Zhitomir Oblast, Ukraine, were obliged to participate in a yearly medical examination. We present the results from these examinations for the years 1993 to 1998. Since the hematopoietic system is an important target, we investigated the association between residential soil density of ¹³⁷Caesium (¹³⁷Cs) and hemoglobin concentration, and erythrocyte, platelet, and leukocyte counts in 1,251 children, using 4,989 repeated measurements taken from 1993 to 1998.</p> <p>Methods</p> <p>Soil contamination measurements from 38 settlements were used as exposures. Blood counts were conducted using the same auto-analyzer in all investigations for all years. We used linear mixed models to compensate for the repeated measurements of each child over the six year period. We estimated the adjusted means for all markers, controlling for potential confounders.</p> <p>Results</p> <p>Data show a statistically significant reduction in red and white blood cell counts, platelet counts and hemoglobin with increasing residential ¹³⁷Cs soil contamination. Over the six-year observation period, hematologic markers did improve. In children with the higher exposure who were born before the accident, this improvement was more pronounced for platelet counts, and less for red blood cells and hemoglobin. There was no exposure×time interaction for white blood cell counts and not in 702 children who were born after the accident. The initial exposure gradient persisted in this sub-sample of children.</p> <p>Conclusion</p> <p>The study is the first longitudinal analysis from a large cohort of children after the Chernobyl accident. The findings suggest persistent adverse hematological effects associated with residential ¹³⁷Cs exposure.</p

Factors Affecting the Crisis in Central Asia (From Ancient Times to the Middle Ages)

This article describes the dynasties and states that ruled Central Asia and the factors that led to the disintegration or collapse of state governance. The period covered in the article focuses on the dynastic states with a centralized state system in the Central Asian region from antiquity to the middle ages.&nbsp

RADIATION SUSPENSION POLYMERIZATION OF ACETYLENE MONOMERS

The regularity of the chemical initiation of ethacididimethylethyl ethynylate polymerization in the presence of solvents such as n-heptane and n-dioxane was studied. A uniform decrease in the relative velocity (Ws/Wm ) of the studied processes with an increase in the solvent fraction is shown, which indicates the identity of the mechanism of their occurrenc

Кинетика и технология переработки галенитсодержащего концентрата Кони Мансур

This study presents the characteristics of the Koni Mansur (Tajikistan) galena concentrate along with the kinetic study results for its leaching in the nitric acid solution. The main minerals (phases) of this concentrate are galena (PbS), sphalerite (ZnS), pyrite (FeS2), chalcopyrite (CuFeS2), anglesite (PbSO4) and quartz (SiO2). The study uses a sample of the concentrate with the following chemical composition, wt.%: Pb – 46.56, Zn – 4.01, Fe – 20.55, Cu – 2.03, S – 21.78, Si – 3.78 and Al – 1.29. The concentrate particle size varies between 0.84 and 148.26 μm. Optimal conditions for the concentrate nitric acid leaching are found to be: temperature t = 55÷65 °C, acid concentration 1.5–2.0 M and the time of concentrate and acid mixture processing 70–90 min. The leaching of concentrate minerals in the acid solution follows the shrinking core mechanism, at 45–65 °C within the kinetic region and with activation energy E = 46.78 kJ/mol. At temperatures below 45 °C, the concentrate nitric acid leaching reaction is inhibited by acid diffusion transfer to the surface of particles with activation energy E = 12.4 kJ/mol. The concentrate processing flow chart is proposed based on the kinetic study results obtained for the mineral leaching process with its main stages described as zero-emission and zero-waste, environmentally friendly, and implemented in a closed cyclic mode with nitric acid regeneration. This results in a significantly cost-effective route for the concentrate leaching process. The resulting associated chemicals are valuable for use in a wide range of industries.Приведены характеристики галенитсодержащего концентрата Кони Мансур (Респ. Таджикистан) и результаты кинетических исследований его выщелачивания в растворе азотной кислоты. Основными минералами (фазами) данного концентрата являются галенит (PbS), сфалерит (ZnS), пирит (FeS2), халькопирит (CuFeS2), англезит (PbSO4) и кварц (SiO2). В исследованиях использована проба концентрата следующего химического состава, мас.%: Pb – 46,56, Zn – 4,01, Fe – 20,55, Cu – 2,03, S – 21,78, Si – 3,78, Al – 1,29. Размер частиц концентрата варьируется в пределах 0,84–148,26 мкм. Оптимальными условиями осуществления азотно-кислотного выщелачивания концентрата являются: температура t = 55÷65 °С, концентрация кислоты 1,52,0 моль/дм3 , время переработки смеси концентрата с кислотой 70–90 мин. Выщелачивание минералов концентрата в растворе кислоты протекает, согласно механизму сокращения поверхности частиц, при температурах 45–65 °С в кинетической области с энергией активации Е = 46,78 кДж/моль, а при t &lt; 45 °С реакция азотно-кислотного выщелачивания концентрата тормозится диффузионным переносом кислоты к поверхности частиц с величиной Е = 12,4 кДж/моль. Предложена технологическая схема переработки концентрата, основанная на результатах кинетики реакции выщелачивания минералов, и охарактеризованы ее основные стадии, которые не имеют выбросов газов и отходов, экологически чистые, не загрязняют природную среду, выполняются в закрытом циклическом режиме с многократным применением азотной кислоты, что значительно снижает себестоимость процесса выщелачивания концентрата. Образующиеся попутные вещества являются ценным материалом для использования в различных производствах