C60 and C60-arginine aqueous solutions: In vitro toxicity and structural study

Abstract

Small-angle X-ray and neutron scattering was applied for the structural characterization of aggregates in water dispersions of fullerene C₆₀ prepared by dialysis method and its conjugate with amino acid arginine. Two compounds are also compared with respect to their toxic properties. Experiments on the cytotoxicity of these systems on the A549, HepG2 and HeLa cells showed no toxic effects of the dispersions.     

Development of new dominant selectable markers for the nonconventional yeasts Ogataea polymorpha and Candida famata

Nonconventional yeast Candida famata and Ogataea polymorpha are interesting organisms for basic and applied studies. O. polymorpha is methylotrophic thermotolerant yeast capable of xylose alcoholic fermentation whereas C. famata is capable of riboflavin overproduction. Still, the new tools for molecular research of these species are needed. The aim of this study was to develop the new dominant selective markers for C. famata and O. polymorpha usable in metabolic engineering experiments. In this work, the BSD gene from Aspergillus terreus coding for blasticidin S deaminase, O. polymorpha AUR1 gene required for sphingolipid synthesis and IMH3 gene, which encodes IMP dehydrogenase, were tested as the new dominant selective marker genes. Our results showed that AUR1 and IMH3 genes could be used as dominant selective markers for O. polymorpha with frequencies of transformation of 40 and 20 transformants per microgram of DNA, respectively. The IMH3 gene was successfully used as the marker for construction of O. polymorpha strains with increased ethanol production from xylose due to overexpression of TAL1, TKL1 and AOX1 genes. The BSD gene from A. terreus, conferring resistance to blasticidin, was found to be efficient for selection of C. famata transformants.     

Comment on“Hole-pinned defect-dipoles induced colossal permittivity in Bi doped SrTiO3ceramics with Sr deficiency”

With this contribution,as a comment to the publication in Journal of Mate rials Science&Technology 44(2020)54,reporting giant dielectric response,structural characterization and numerical simulations in Sr_(1-1.5 x)Bi_xTiO₃ceramics,we show that the re ported results are rather contradicting and not well analysed,while the suggested mechanism for the giant permittivity response is not valid or doubtful and has to be reconsidered.Moreover,many details and data are missing making impossible not only to call the obtained results very suitable for practical application but even to reproduce them.     

Simulation and Experimental Validation of Spacer Fabrics Based on their Structure and Yarn’s Properties

Warp-knitted spacer fabrics are considered, which are plates or shells composed of two knitted plane layers connected by vertical beams. Our aim is to compute the effective stiffness and permeability of such spacer fabrics on the basis of their structure and properties of yarns and the monofil. In order to reduce the computational effort and simplify the computational model, homogenization and dimension reduction techniques are applied. They replace the fabric by an equivalent two-dimensional plate or shell with effective elastic properties. To compute the effective permeability, the fluid simulation is done on the fully resolved micro-structure. The paper demonstrates the algorithm on application examples. We compute the elastic properties of a spacer fabric and its effective permeability for different outer-plane compression stages. Numerical examples were performed by applying the multi-scale simulation tools, developed at Fraunhofer ITWM and by comparing with the corresponding experimental results, based on measurements performed at the TU Dresden. The developed algorithms and simulation tools enable a full virtualisation of the material design adapted to exposure scenarios in various technical application cases, i.e. infiltration processes with polymers in the field of fiber reinforced composites, which enables new discoveries for the designing and manufacturing process of 3D warp-knitted spacer fabrics.     

Acceptance Sampling Plans with Truncated Life Tests for the Length-Biased Weighted Lomax Distribution

In this paper, we considered the Length-biased weighted Lomax distribution and constructed new acceptance sampling plans (ASPs) where the life test is assumed to be truncated at a pre-assigned time. For the new suggested ASPs, the tables of the minimum samples sizes needed to assert a specific mean life of the test units are obtained. In addition, the values of the corresponding operating characteristic function and the associated producer’s risks are calculated. Analyses of two real data sets are presented to investigate the applicability of the proposed acceptance sampling plans; one data set contains the first failure of 20 small electric carts, and the other data set contains the failure times of the air conditioning system of an airplane. Comparisons are made between the proposed acceptance sampling plans and some existing acceptance sampling plans considered in this study based on the minimum sample sizes. It is observed that the samples sizes based on the proposed acceptance sampling plans are less than their competitors considered in this study. The suggested acceptance sampling plans are recommended for practitioners in the field.     

Structural Determinants of Workforce Participation after Retirement in Poland

In this paper, we aim to analyse selected structural determinants of workforce participation after retirement in Poland. By structural determinants we mean characteristics of one’s socio-economic position that (a) result from the interplay of social conditions (mechanisms of power, differentiated access to resources) and individual agency, and (b) restrict or facilitate individuals’ choices. We conceptualise workforce participation as engaging in either part- or full-time paid employment despite receiving the old-age pension. Our general hypothesis is that working in older age is not only a matter of motivation or psychological traits but also a complex interplay of structural characteristics, accumulated by individuals during their life course. In the paper, we test a number of hypotheses about the role of specific components of socio-economic status (SES), i.e. occupational prestige, education, and wealth, for workforce participation among retirees. We argue that, in case of retirees, the prestige of the last job before retirement is a more reliable measure of the social position than education. Hence, we conduct a more detailed analysis of the role of occupational prestige for the chances of being employed after retirement. The analysis was based on data gathered in the years 2013–2014 within the sixth wave of the Polish Panel Survey POLPAN (www.polpan.org). We extracted a subsample of retirees from this dataset and used logistic regression to test the hypotheses described above. We found that both occupational prestige of the last job before retirement and educational attainments are strong predictors of being in paid work after retirement, however the impact of occupational prestige varies across the groups with the lowest and higher level of retirement pension. We also found that there are horizontal differences in the occupational structure of the chances for workforce participation after retirement and additionally found that being a farm owner increases the propensity to engage in economic activity after retirement. The paper contributes to the field of studies on the relationship between SES and workforce participation after retirement in line with the cumulative advantage/disadvantage theory and shows that resources that individuals have accumulated during the life course can determine their chances of working after retirement just as individual motivations or organisational characteristics do.     

Bromide substitution in lithium borohydride, LiBH4-LiBr

By means of in situ synchrotron radiation powder X-ray diffraction, powder neutron diffraction, attenuated total reflectance infrared spectroscopy, differential scanning calorimetry and the Sieverts techniques we have investigated how anion substitution in the LiBH₄-LiBr system leads to changes in the structural, physical, chemical and hydrogen storage properties of this material. Mechano-chemical treatment facilitates formation of a hexagonal solid solution h-Li(BH₄)_1−xBr_x whereas heating at elevated temperatures, i.e. T > 112 °C appears to allow full solubility in the system LiBH₄−LiBr. The first step in the anion substitution process may be dissolution of small amounts of LiBH₄ in α-LiBr deduced from observation of a hexagonal solid solution with unit cell volume similar to β-LiBr for a hand-mixed sample. The solid solution, Li(BH₄)_1−xBr_x, is isostructural to the hexagonal high temperature polymorph of LiBH₄. This solid solution melts at a significantly higher temperature depending on the composition as compared to h-LiBH₄. Furthermore, a new hexalithium borate tribromide, Li₆(BO₃)Br₃ was discovered and structurally characterized.