Oxygen and structure transformations of h-BN in focal zone of an optical furnace

In this contribution the recent results on a synthesis of the new structures of boron nitride are presented. Light-induced catalyst-free heating of fine-grained graphite-like h-BN powders was performed in the flow of dried and purified nitrogen in an optical furnace. The new structures of boron nitride were obtained. Scanning electron microscopy JSM-6490 supplemented with combined Energy Dispersive X-ray Spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD) provided information about structures, phase and element transformation of fine-grained graphite-like h-BN powders. The coarse structures, thread-like nanostructures (whiskers or dendritic structures) and new morphologies were formed due to the interaction of BN plume with nitrogen ambient on the surface of the heated compacted h-BN samples. Complicated structure and element composition of the whiskers which were formed on the surface of heated samples of compacted h-BN powders were studied by scanning electron microscopy (SEM). X-ray Diffraction (XRD) study demonstrates presence of amorphous phase, pure boron of different modifications and boron nitride of different phase compositions on the surface of these substrates. The process of the synthesis, formation and growth of the nanostructures in an optical furnace was analyzed and understood. A role of oxygen in formation and growth mechanism of BN whiskers was proposed

BXD recombinant inbred mice as a model to study neurotoxicity

BXD recombinant inbred (RI) lines represent a genetic reference population derived from a cross between C57BL/6J mice (B6) and DBA/2J mice (D2), which through meiotic recombination events possesses recombinant chromosomes containing B6 or D2 haplotype segments. The quantitative trait loci (QTLs) are the locations of segregating genetic polymorphisms and are fundamental to understanding genetic diversity in human disease susceptibility and severity. QTL mapping represents the typical approach for identifying naturally occurring polymorphisms that influence complex phenotypes. In this process, genotypic values at markers of known genomic locations are associated with phenotypic values measured in a segregating population. Indeed, BXD RI strains provide a powerful tool to study neurotoxicity induced by different substances. In this review, we describe the use of BXD RI lines to understand the underlying mechanisms of neurotoxicity in response to ethanol and cocaine, as well as metals and pesticide exposures. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Serum copper, zinc, and iron levels, and markers of carbohydrate metabolism in postmenopausal women with prediabetes and type 2 diabetes mellitus

The objective of the present study was to evaluate serum level of copper, zinc, iron and metabolic parameters in postmenopausal women with diabetes. A total of 413 postmenopausal women were enrolled in the current study. Women were divided into 4 groups with equal age and body mass index according to glycated hemoglobin (HbA1c) levels (≤5.5; 5.5–6.0; 6.0–6.5; >6.5%). Serum Fe, Cu, and Zn levels were assessed using inductively-coupled plasma mass-spectrometry. Blood HbA1c, serum glucose, insulin, C-reactive protein (CRP), ferritin, and ceruloplasmin (Cp) were assessed using commercial kits. Homeostatic model assessment insulin resistance (HOMA-IR) and transferrin (Tf) saturation were calculated. The obtained data demonstrate that every 0.5% increase in HbA1c levels from 5.5% is associated with a significant elevation of glucose, insulin, CRP, and HOMA-IR values. Diabetic patients were characterized by significantly higher Fe (11%), Cu (8%), and Zn (6%) levels as compared to the controls. At the same time, the overall trend to increased metal levels in association with HbA1c was detected only for Fe (p < 0.05) and Cu (p < 0.05). Serum ferritin levels in diabetic women was 3-fold higher than in the controls, whereas Tf saturation was decreased by 35%. Serum Cp levels were significantly increased by 19% in prediabetes, whereas in diabetic postmenopausal women no such increase was observed. A significant elevation of total metal concentration in diabetic subjects without a concomitant elevation of transport proteins may be indicative of increased levels of “free” Fe and Cu, known to be toxic. © 2016 Elsevier Gmb

Влияние интенсивной физической нагрузки на механизмы регуляции обмена железа

Intense physical activity has a significant effect on iron metabolism in the human organism. This paper is a review of the world literature data focused on the mechanisms of regulation of iron metabolism in the body, as well as the influence of intense exercises on these regulatory mechanisms. We discussed the mechanisms of iron absorption and transport and the regulation of these processes in normal conditions. It was found that intensive exercise is accompanied by increased production of interleukin-6, a positive regulator of hepcidin production. The latter in turn has an inhibitory effect on the expression of the divalent metal transporter 1 and ferroportin, finally leading to both decreased iron absorption and iron sequestration in cells. All mentioned stages of the development of iron deficiency may be promising targets of iron balance correction and working ability in patients exposed to intense physical activity.Интенсивная физическая нагрузка оказывает существенное влияние на обмен железа в организме человека. Целью данной работы является обзор литературы, посвященной изучению регуляции обмена железа в организме, а также влияния интенсивной физической нагрузки на данные механизмы. Рассмотрены механизмы всасывания, транспорта железа, а также регуляции данных процессов. Литературные данные свидетельствуют о том, что интенсивная физическая нагрузка сопровождается увеличением продукции интерлейкина-6, являющегося положительным регулятором продукции гепсидина. Последний, в свою очередь, оказывает тормозное влияние на экспрессию транспортера двухвалентных металлов (DMT-1) и ферропортина, что приводит, с одной стороны, к снижению всасывания, а с другой, секвестрации железа в клетках. Воздействие на рассмотренные звенья развития железодефицита может являться перспективным средством коррекции баланса железа и работоспособности лиц, подверженных интенсивной физической нагрузке

The joint 16th symposium on Trace Elements in Man and Animals (TEMA16), International Society for Trace Element Research in Humans (ISTERH-2017) and Nordic Trace Element Society (NTES), Saint-Petersburg, Russia, 26–29 June, 2017

[No abstract available

Serum copper, zinc, and iron levels, and markers of carbohydrate metabolism in postmenopausal women with prediabetes and type 2 diabetes mellitus

The objective of the present study was to evaluate serum level of copper, zinc, iron and metabolic parameters in postmenopausal women with diabetes. A total of 413 postmenopausal women were enrolled in the current study. Women were divided into 4 groups with equal age and body mass index according to glycated hemoglobin (HbA1c) levels (≤5.5; 5.5–6.0; 6.0–6.5; >6.5%). Serum Fe, Cu, and Zn levels were assessed using inductively-coupled plasma mass-spectrometry. Blood HbA1c, serum glucose, insulin, C-reactive protein (CRP), ferritin, and ceruloplasmin (Cp) were assessed using commercial kits. Homeostatic model assessment insulin resistance (HOMA-IR) and transferrin (Tf) saturation were calculated. The obtained data demonstrate that every 0.5% increase in HbA1c levels from 5.5% is associated with a significant elevation of glucose, insulin, CRP, and HOMA-IR values. Diabetic patients were characterized by significantly higher Fe (11%), Cu (8%), and Zn (6%) levels as compared to the controls. At the same time, the overall trend to increased metal levels in association with HbA1c was detected only for Fe (p < 0.05) and Cu (p < 0.05). Serum ferritin levels in diabetic women was 3-fold higher than in the controls, whereas Tf saturation was decreased by 35%. Serum Cp levels were significantly increased by 19% in prediabetes, whereas in diabetic postmenopausal women no such increase was observed. A significant elevation of total metal concentration in diabetic subjects without a concomitant elevation of transport proteins may be indicative of increased levels of “free” Fe and Cu, known to be toxic. © 2016 Elsevier Gmb

Arsenic, cadmium, mercury, and lead levels in hair and urine in first-year RUDN University students of different geographic origins

The objective of the present study was to assess the markers of arsenic, cadmium, mercury, and lead exposure in first-year RUDN University students of different geographic origins. A total of 274 first-year students of the RUDN University originating from Russia (n = 65), Asia (n = 57), Middle East (n = 84), Africa (n = 40), and Latin America (n = 28) were enrolled in the present study. Evaluation of As, Cd, Hg, and Pb levels in urine and hair was performed using inductively coupled plasma-mass spectrometry. The obtained data demonstrate that hair As levels in foreign students exceed that in Russian examinees. The highest Cd and Pb levels were detected in subjects from Africa and Latin America, whereas hair Hg content was significantly higher in Latin America students. Urinary Cd levels in foreign students exceeded those in Russian counterparts. In turn, the highest Hg concentration in urine was revealed in students originating from Middle East and especially Latin America. Urinary Pb levels were found to be the highest in students from Africa. Multiple regression analysis demonstrated that Asian, African, and Latin American origins were considered as a significant predictor of hair Hg content. Higher urinary Hg levels were associated with Asia, Middle East, and Latin American origins. Prior habitation in Africa and Asia was considered as predictor of higher hair Pb and urinary Cd levels. The observed difference may be indicative of geographic difference in toxic metal exposure patterns. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature

A Case-Control Study of Essential and Toxic Trace Elements and Minerals in Hair of 0–4-Year-Old Children with Cerebral Palsy

The objective of the present study was to assess hair essential and toxic trace elements and minerals in children with cerebral palsy in relation to age of the examinees. A total of 70 children with cerebral palsy and 70 healthy controls aged 0–4 years old were enrolled in the present study. The examined children were also divided into two age groups of those younger and older than 2 years old. Hair trace element content was assessed using ICP-MS at NexION 300D (PerkinElmer, USA). The obtained data demonstrate that hair boron was more than 2-fold lower in CP children as compared with the control group. At the same time, hair Na, Se, and V levels were 21%, 12%, and 20% lower when compared with healthy controls, respectively. It is also notable that a 9% and 28% decrease in hair Fe and Li levels respectively were nearly significant. The observed alterations were more profound in a younger group of patients. No significant group difference in hair toxic metal and metalloid levels was observed between the general cohorts of children with and without CP. In regression models, only hair Al and Ca contents were significantly associated with the presence of cerebral palsy, whereas hair Mg, Na, Ni, and Se levels were characterized as significant negative predictors. The observed alteration in trace element metabolism may also provide an additional link between cerebral palsy, psychomotor delay, and certain diseases, including diabetes, epilepsy, and osteoporosis. However, further studies using other substrates (blood, urine) or biomarkers are required. © 2019, Springer Science+Business Media, LLC, part of Springer Nature

Influence of Physical Activity on the Regulation of Iron Metabolism

Abstract: Intense physical activity has a significant effect on iron metabolism in the human organism. This paper is a review of world literature data focused on the mechanisms of iron metabolism regulation in the human organism, as well as the influence of intense exercise on these regulatory mechanisms. We have discussed the mechanisms of iron absorption and transport and the regulation of these processes under normal conditions. It has been found that intense exercise is accompanied by increased production of interleukin-6, a positive regulator of hepcidin production. Hepcidin, in turn, has an inhibitory effect on the expression of divalent metal transporter 1 and ferroportin, finally leading to both decreased iron absorption and iron sequestration in cells. All of the mentioned stages of iron deficiency development may be promising targets for correction of iron balance and working ability in patients exposed to intense physical activity. © 2018, Pleiades Publishing, Inc