The Difference of Structural State and Deformation Behavior between Teenage and Mature Human Dentin

Objective. The cause of considerable elasticity and plasticity of human dentin is discussed in the relationship with its microstructure. Methods. Structural state of teenage and mature human dentin is examined by using XRD and TEM techniques, and their deformation behavior under compression is studied as well. Result. XRD study has shown that crystallographic type of calcium hydroxyapatite in human dentin (calcium hydrogen phosphate hydroxide Ca9HPO4(PO4)5OH; Space Group P63/m (176); a = 9,441 A; c = 6,881 A; c/a = 0,729; Crystallite (Scherrer) 200 A) is the same for these age groups. In both cases, dentin matrix is X-ray amorphous. According to TEM examination, there are amorphous and ultrafine grain phases in teenage and mature dentin. Mature dentin is stronger on about 20% than teenage dentin, while teenage dentin is more elastic on about 20% but is less plastic on about 15% than mature dentin. Conclusion. The amorphous phase is dominant in teenage dentin, whereas the ultrafine grain phase becomes dominant in mature dentin. Mechanical properties of human dentin under compression depend on its structural state, too

Cellular effects of terahertz waves

Significance: An increasing interest in the area of biological effects at exposure of tissues and cells to the terahertz (THz) radiation is driven by a rapid progress in THz biophotonics, observed during the past decades. Despite the attractiveness of THz technology for medical diagnosis and therapy, there is still quite limited knowledge about safe limits of THz exposure. Different modes of THz exposure of tissues and cells, including continuous-wave versus pulsed radiation, various powers, and number and duration of exposure cycles, ought to be systematically studied. Aim: We provide an overview of recent research results in the area of biological effects at exposure of tissues and cells to THz waves. Approach: We start with a brief overview of general features of the THz-wave–tissue interactions, as well as modern THz emitters, with an emphasis on those that are reliable for studying the biological effects of THz waves. Then, we consider three levels of biological system organization, at which the exposure effects are considered: (i) solutions of biological molecules;(ii) cultures of cells, individual cells, and cell structures; and (iii) entire organs or organisms; special attention is devoted to the cellular level. We distinguish thermal and nonthermal mechanisms of THz-wave–cell interactions and discuss a problem of adequate estimation of the THz biological effects’ specificity. The problem of experimental data reproducibility, caused by rareness of the THz experimental setups and an absence of unitary protocols, is also considered. Results: The summarized data demonstrate the current stage of the research activity and knowledge about the THz exposure on living objects. Conclusions: This review helps the biomedical optics community to summarize up-to-date knowledge in the area of cell exposure to THz radiation, and paves the ways for the development of THz safety standards and THz therapeutic applications

Разработка технологии переработки упорных золотосодержащих концентратов на покровском автоклавно-гидрометаллургическом комплексе

The chemical composition and mineralogy of Malomir and Pioneer gold-bearing ores were discussed. The main gold forms in the ores were indicated: the preferential gold association with sulfide minerals was noted. The chemical composition of sulfide flotation concentrates was shown. The laboratory and pilot tests results of concentrates pressure oxidation were introduced. The influence of organic carbon content in the concentrate and chloride ion content in the liquid phase of pressure oxidation slurry on the gold extraction from materials were noted and researched. The effect of preliminary treatment stages on POX indicators was shown. The positive effect of hot autoclave slurry conditioning on gold recovery was noted. The process flow sheet for treating both Malomir and Pioneer ores was developed and advisedРассмотрен химический состав и минералогия маломирских и пионерских золотоносных руд. Указаны основные формы золота в рудах: отмечено преимущественное соединение золота с сульфидными минералами. Показан химический состав сульфидных флотационных концентратов. Представлены результаты лабораторных и полупромышленных испытаний окисления концентратов под давлением. Отмечено и исследовано влияние содержания органического углерода в концентратах и содержания ионов хлорида в жидкой фазе суспензии окисления под давлением на извлечение золота из материалов. Показано влияние предварительных стадий обработки по показателям технологии автоклавного окисления. Отмечено положительное влияние обработки горячей автоклавной суспензией на извлечение золота. Разработана и рекомендована технологическая схема процесса обработки маломирских и пионерских ру

Effect of Abscisic Acid on Growth, Fatty Acid Profile, and Pigment Composition of the Chlorophyte <i>Chlorella (Chromochloris) zofingiensis</i> and Its Co-Culture Microbiome

Microalga Chlorella (Chromochloris) zofingiensis has been gaining increasing attention of investigators as a potential competitor to Haematococcus pluvialis for astaxanthin and other xanthophylls production. Phytohormones, including abscisic acid (ABA), at concentrations relevant to that in hydroponic wastewater, have proven themselves as strong inductors of microalgae biomass productivity and biosynthesis of valuable molecules. The main goal of this research was to evaluate the influence of phytohormone ABA on the physiology of C. zofingiensis in a non-aseptic batch experiment. Exogenous ABA stimulated C. zofingiensis cell division, biomass production, as well as chlorophyll, carotenoid, and lipid biosynthesis. The relationship between exogenous ABA concentration and the magnitude of the observed effects was non-linear, with the exception of cell growth and biomass production. Fatty acid accumulation and composition depended on the concentration of ABA tested. Exogenous ABA induced spectacular changes in the major components of the culture microbiome of C. zofingiensis. Thus, the abundance of the representatives of the genus Rhodococcus increased drastically with an increase in ABA concentration, whereas the abundance of the representatives of Reyranella and Bradyrhizobium genera declined. The possibilities of exogenous ABA applications for the enhancing of the biomass, carotenoid, and fatty acid productivity of the C. zofingiensis cultures are discussed

Разработка технологии переработки упорных золотосодержащих концентратов на покровском автоклавно-гидрометаллургическом комплексе

The chemical composition and mineralogy of Malomir and Pioneer gold-bearing ores were discussed. The main gold forms in the ores were indicated: the preferential gold association with sulfide minerals was noted. The chemical composition of sulfide flotation concentrates was shown. The laboratory and pilot tests results of concentrates pressure oxidation were introduced. The influence of organic carbon content in the concentrate and chloride ion content in the liquid phase of pressure oxidation slurry on the gold extraction from materials were noted and researched. The effect of preliminary treatment stages on POX indicators was shown. The positive effect of hot autoclave slurry conditioning on gold recovery was noted. The process flow sheet for treating both Malomir and Pioneer ores was developed and advisedРассмотрен химический состав и минералогия маломирских и пионерских золотоносных руд. Указаны основные формы золота в рудах: отмечено преимущественное соединение золота с сульфидными минералами. Показан химический состав сульфидных флотационных концентратов. Представлены результаты лабораторных и полупромышленных испытаний окисления концентратов под давлением. Отмечено и исследовано влияние содержания органического углерода в концентратах и содержания ионов хлорида в жидкой фазе суспензии окисления под давлением на извлечение золота из материалов. Показано влияние предварительных стадий обработки по показателям технологии автоклавного окисления. Отмечено положительное влияние обработки горячей автоклавной суспензией на извлечение золота. Разработана и рекомендована технологическая схема процесса обработки маломирских и пионерских ру

Geological objects and physical parameter fields in the subsurface: a review

International audienceGeologists and geophysicists often approach the study of the Earth using different and complementary perspectives. To simplify, geologists like to define and study objects and make hypotheses about their origin, whereas geo-physicists often see the earth as a large, mostly unknown multivariate parameter field controlling complex physical processes. This paper discusses about some strategies to combine both approaches. In particular, I review some practical and theoretical frameworks associating petrophysical heterogeneities to the geometry and the history of geological objects. These frameworks open interesting perspectives to define prior parameter space in geophysical inverse problems, which can be consequential in under-constrained cases