Analysis of Relation Between Lifetime Rates and Incorporation of Plutonium-239 in Atomic Production Workers Regarding Tumor and Non-Tumor Causes of Death

Purpose: The objective of the study was in quantitative assessment of the effect of internal exposure to lifetime in Mayak PA workers based on analyzing dependence of certain lifetime rates on incorporation of plutonium-239 regarding tumor and non-tumor causes of death. Material and methods: The cohort of deceased Mayak PA workers employed in1948–1958 with known Pu-239 body burden comprising 2343 individuals, of them 1739 males and 604 females, was investigated. Using regression analysis we have assessed dependence of general lifetime and lifetime after start of work as well as of proportion of individuals who did not survive until standard age in general and after start of work from incorporated Pu-239 separately for workers of different age regarding tumor and non-tumor causes of death. Statistical values were defined using Statistica software. Results: It was stated that in case of increase of plutonium-239 body burden in males and females reliably increased shortening of lifetime and lifetime after start of work was observed as well as increased proportion of individuals who did not survive until standard lifetime rate and until standard lifetime after start of work. Reliable regression equations for dependence of the studied lifetime values from radionuclide incorporation rate were obtained based on regression analysis. Generally, changes in the studied characteristics of lifetime after start of work were more evident than in general lifetime characteristics. Conclusion: Reliable dependence of shortening of lifetime and lifetime after start of work, of increased proportion of individuals who did not survive until standard lifetime and lifetime after start of work among Mayak PA workers of different gender from incorporation of plutonium-239 regarding tumor and non-tumor causes of death was stated. Dependence of lifetime after start of work on incorporated plutonium-239 was higher than of general lifetime that could be probably due to direct contact of workers with radionuclide after start of work. The results obtained indicate feasibility of using not only general lifetime but also lifetime after start of work in assessment of lifetime among workers who are in contact with production hazardous factors.

Strength index analysis of concrete with large size recycled aggregate based on back propagation neural network

A back propagation (BP) neural network (NN) model was used to analyze the relationship between the cube compressive strength and various strength indicators of concrete with large-sized recycled aggregates (LSRA) (80 mm maximum size). Factors such as strength and replacement rate of recycled aggregates were used as input parameters to establish the neural network model. The BP-NN model was optimized by analyzing the influence and sensitivity of each parameter in the model. Then the mechanical properties of concrete with LSRA were predicted. Results showed that the strength of new concrete had a more significant impact on the strength of recycled concrete with LSRA, followed by the strength of old concrete. While considering all the factors, including the mechanical strength and the replacement ratio regarding the maximum utilization of RA, the 30% incorporation rate was suggested as an ideal incorporation rate.

Individual growth models support the quantification of isotope incorporation rate, trophic discrimination and their interactions

Two large but independent bodies of literature exist on two essential components of the dynamics of isotopic incorporation: the isotopic incorporation rate (λ) and the trophic discrimination factor (Δ). Understanding the magnitude of these two parameters and the factors that shape them is fundamental to interpret the results of ecological studies that rely on stable isotopes. λ scales allometrically with body mass among species and depends on growth within species. Both are often assumed to be constant and independent of each other but evidence accumulates that might be linked and to vary with growth. We built and analyzed a model (IsoDyn) that connects individual growth and isotopic incorporation of nitrogen into whole body and muscle tissues. The model can assume a variety of individual growth patterns including exponential or asymptotic growths. λ depends on the rate of body mass gains which scales allometrically with body mass. Δ is a dynamic response variable that depends partly on the ratio between fluxes of gains and losses and covaries negatively with λ. The model can be parameterized either from existing large databases of animal growth models or directly from experimental results. The model was applied to experimental results on three ectotherms and one endotherm and compared to the results of the simpler and widely used time model. IsoDyn model gave a better fit with relatively little calibration. IsoDyn clarifies and expands the interpretation of isotopic incorporation data.

Correction: Rapid kinetic evaluation of homogeneous single-site metallocene catalysts and cyclic diene: how do the catalytic activity, molecular weight, and diene incorporation rate of olefins affect each other?

Correction for ‘Rapid kinetic evaluation of homogeneous single-site metallocene catalysts and cyclic diene: how do the catalytic activity, molecular weight, and diene incorporation rate of olefins affect each other?’ by Amjad Ali et al., RSC Adv., 2021, 11, 31817–31826, DOI: 10.1039/D1RA06243C.

Syndiospecific coordination (Co)polymerization of carbazole-substituted styrene derivatives using the scandium catalyst system

Perfect syndiospecific polymerization of carbazole-substituted styrene derivatives was achieved using a rare-earth metal catalyst. Also copolymerization of FSt with styrene afforded copolymers with gradient sequence distributions and easily tunable incorporation rate.

Rapid kinetic evaluation of homogeneous single-site metallocene catalysts and cyclic diene: how do the catalytic activity, molecular weight, and diene incorporation rate of olefins affect each other?

The kinetics and mechanism of ethylene and 5-ethylidene-2-norbornene copolymerization catalyzed by rac-Et(Ind)2ZrCl2 were investigated using 2-thiophenecarbonyl chloride.

The mathematical model for forecasting the accumulation of heavy metals in pig production

The results of research represent the impact of extensive doses of heavy metals such as lead and cadmium in store pigs bodies. Heavy metals were fed jointly and individually in the doses exceeding the maximum allowable concentrations in the fodder by 10 and 20 times. Therefore, the process of intoxication of the biological object (a swine) by heavy metals is modeled in a way similar to that, which might occur as the result of environmental pollution. The study was performed in order to determine the targets and the extent of the impact of heavy metals exerted upon the body weight, weight of inner parts of the animal body, and the incorporation rate of heavy metals in the swine breeding products. Statistical processing of the obtained data allowed developing mathematical models and determining the correlational relationships between the aspects under investigation. It is determined that heavy metals exert an essential negative impact upon the rate of animal growth and the power of influence increases with the dose. It is also confirmed by a high value of correlational relationship between these parameters (the correlation coefficient (r) is 0.854). Thus, the body weight of swine during the latter of I-II stagesdecreased by 5.5 to 14.8% as it was compared to the control under the influence of hemotoxic substances. The extent of the impact was also dependent upon the toxin itself. Thus, the largest negative effect was observed both under the impact of cadmium only and of cadmium and lead taken together. The highest accumulation of heavy metals was observed in the liver and kidneys, whereas the lowest – in the muscles. The built regression equations showed that increasing of the dose of the relevant element in the fodder exerted the main impact on concentration of cadmium and lead in the body and meat. The content of cadmium in the fodder exerted an impact upon concentration of lead in the meat – with the increase of cadmium concentration the content of lead in the meat decreased. The results of the studies provide an overview of the targets and the extent of the impact exerted by heavy metals upon biological objects. The mathematical models may be used for prediction of the impact and the incorporation rate value of the hemotoxic substances in the swine breeding products. Key words: lead, cadmium, swine breeding products, ecocide environmental impact, migration of xenobiotic, mathematical model.

Development of Monolithically Grown Coaxial GaInN/GaN Multiple Quantum Shell Nanowires by MOCVD

Broadened emission was demonstrated in coaxial GaInN/GaN multiple quantum shell (MQS) nanowires that were monolithically grown by metalorganic chemical vapor deposition. The non-polar GaInN/GaN structures were coaxially grown on n-core nanowires with combinations of three different diameters and pitches. To broaden the emission band in these three nanowire patterns, we varied the triethylgallium (TEG) flow rate and the growth temperature of the quantum barriers and wells, and investigated their effects on the In incorporation rate during MQS growth. At higher TEG flow rates, the growth rate of MQS and the In incorporation rate were promoted, resulting in slightly higher cathodoluminescence (CL) intensity. An enhancement up to 2–3 times of CL intensity was observed by escalating the growth temperature of the quantum barriers to 800 °C. Furthermore, decreasing the growth temperature of the quantum wells redshifted the peak wavelength without reducing the MQS quality. Under the modified growth sequence, monolithically grown nanowires with a broaden emission was achieved. Moreover, it verified that reducing the filling factor (pitch) can further promote the In incorporation probability on the nanowires. Compared with the conventional film-based quantum well LEDs, the demonstrated monolithic coaxial GaInN/GaN nanowires are promising candidates for phosphor-free white and micro light-emitting diodes (LEDs).