Observation of a triple correlation in ternary fission: is time reversal invariance violated?

In ternary fission, besides the two main fission fragments, a third (usually light) charged particle is emitted. A triple correlation has been studied involving the momenta for a specific fission fragment , the momenta of the ternary particle and the spin of the polarized cold neutron inducing fission . The correlation observable reverses sign upon time reversal and thus a non-vanishing value for the expectation value B could possibly be due to TRI being violated. However, final-state interactions or specific properties of the emission mechanism for ternary particles could equally well lead to a non-zero B with TRI being perfectly conserved. The reaction chosen was ²³³U(n,f). An unexpectedly large correlation was observed. From the raw data the value for B is B=−(0.78±0.02)×10⁻³ with the sign corresponding to light fragments. Corrections for neutron polarization, geometric efficiency, resolution of detectors and background increase this figure by a factor of (1.5±0.3).     

Novel A-Ring Chalcone Derivatives of Oleanolic and Ursolic Amides with Anti-Proliferative Effect Mediated through ROS-Triggered Apoptosis

A series of A-ring modified oleanolic and ursolic acid derivatives including C28 amides (3-oxo-C2-nicotinoylidene/furfurylidene, 3β-hydroxy-C2-nicotinoylidene, 3β-nicotinoyloxy-, 2-cyano-3,4-seco-4(23)-ene, indolo-, lactame and azepane) were synthesized and screened for their cytotoxic activity against the NCI-60 cancer cell line panel. The results of the first assay of thirty-two tested compounds showed that eleven derivatives exhibited cytotoxicity against cancer cells, and six of them were selected for complete dose–response studies. A systematic study of local SARs has been carried out by comparative analysis of potency distributions and similarity relationships among the synthesized compounds using network-like similarity graphs. Among the oleanane type triterpenoids, C2-[4-pyridinylidene]-oleanonic C28-morpholinyl amide exhibited sub-micromolar potencies against 15 different tumor cell lines and revealed particular selectivity for non-small cell lung cancer (HOP-92) with a GI₅₀ value of 0.0347 μM. On the other hand, superior results were observed for C2-[3-pyridinylidene]-ursonic N-methyl-piperazinyl amide 29, which exhibited a broad-spectrum inhibition activity with GI₅₀ < 1 μM against 33 tumor cell lines and <2 μM against all 60 cell lines. This compound has been further evaluated for cell cycle analysis to decipher the mechanism of action. The data indicate that compound 29 could exhibit both cytostatic and cytotoxic activity, depending on the cell line evaluated. The cytostatic activity appears to be determined by induction of the cell cycle arrest at the S (MCF-7, SH-SY5Y cells) or G₀/G₁ phases (A549 cells), whereas cytotoxicity of the compound against normal cells is nonspecific and arises from apoptosis without significant alterations in cell cycle distribution (HEK293 cells). Our results suggest that the antiproliferative effect of compound 29 is mediated through ROS-triggered apoptosis that involves mitochondrial membrane potential depolarization and caspase activation.     

Formation of medium-range order in fluoride glasses

A possible solution to the problem of determining the medium-range order in fluoride glasses is proposed. The model of the formation of the glass network is advanced on the basis of the complex-cluster model for salt melts and the percolation hypothesis. The determination of the glass network topology reduces to the experimental determination of the percolation point and the geometric estimation of the second coordination number of a glass-former. It is shown that the functionalities of glass-formers as determined from both the percolation point and the crystal chemical constraints turn out to be identical.     

用于激光起爆的新型光敏炸药——过氯酰胺(英)

介绍了过氯酰胺盐的一些性质,指出过氯酰胺盐是激光起爆阈值低的光敏炸药。用１０％光学透明的聚合物分别５０ｍｇ／ｃｍ＾２的过氯酰胺钾和过氯酰胺钡制１ｃｍ＾２的光敏炸药薄板并进行了实验。Ⅱ的起爆阈值经久０．１Ｊ／ｃｍ＾２,Ⅳ的起爆阈值为５－７ｍＪ／ｃｍ＾２,皆低于压装的叠氮化铅药柱,全都实现了平面起爆。     

Plasmids as Key Players in Acinetobacter Adaptation

This review briefly summarizes the data on the mechanisms of development of the adaptability of Acinetobacters to various living conditions in the environment and in the clinic. A comparative analysis of the genomes of free-living and clinical strains of A. lwoffii, as well as the genomes of A. lwoffii and A. baumannii, has been carried out. It has been shown that plasmids, both large and small, play a key role in the formation of the adaptability of Acinetobacter to their living conditions. In particular, it has been demonstrated that the plasmids of various strains of Acinetobacter differ from each other in their structure and gene composition depending on the lifestyle of their host bacteria. Plasmids of modern strains are enriched with antibiotic-resistant genes, while the content of genes involved in resistance to heavy metals and arsenic is comparable to plasmids from modern and ancient strains. It is concluded that Acinetobacter plasmids may ensure the survival of host bacteria under conditions of various types of environmental and clinical stresses. A brief overview of the main mechanisms of horizontal gene transfer on plasmids inherent in Acinetobacter strains is also given.     

Transparent Glass-Ceramic Materials Based on Lead Fluoroborate Glasses Co-Activated by Eu/Gd

Glass and Ceramics - Transparent glass-ceramic materials co-activated by Eu3+/Gd3+ were obtained by heat treatment of the initial lead fluoroborate glasses. It was found that the rare-earth ions in...     

Influence of Nitriding on the Wear Resistance and Adhesion of Zinc Coatings on Steel

Russian Engineering Research - Chemicothermal treatment of steel is considered: specifically, diffusional zinc coating in a nitrogen-bearing medium; and nitriding of a preformed zinc-filled...