Chromosomal instability and double minute chromosomes in a breast cancer patient.

Cytogenetic analysis was performed in peripheral blood lymphocytes (PBL) of a woman with ductal breast carcinoma, who as a hospital employee was exposed professionally for 15 years to low doses of ionizing radiation. The most important finding after the chemotherapy in combination with radiotherapy was the presence of double minutes (DM) chromosomes, in combination with other chromosomal abnormalities (on 200 scored metaphases were found 2 chromatid breaks, 10 dicentrics, 11 acentric fragments, 2 gaps, and 3 double min chromosomes). In a repeated analysis (after 6 months), DM chromosomes were still present. To rule out the possibility that the patient was overexposed to ionizing radiation at work, her blood test was compared with a group of coworkers as well as with a group of professionally unexposed people. The data rejected this possibility, but the retroactive analysis showed that the patient even at the time of employment had a moderately increased number of chromosomal aberrations (3.5%) consisting of 3 isochromatids and 4 gaps, suggesting that her initial genomic instability enhanced the later development. The finding of a continuous presence of rare DM chromosomes in her PBL (4 and 10 months after radiochemotherapy) was considered as an indicator of additional risk, which might have some prognostic significance.</p

Comparison of chromosome aberrations in peripheral blood lymphocytes from people occupationally exposed to ionizing and radiofrequency radiation.

The genotoxic effects of occupational exposure to ionizing and non-ionizing radiation were investigated in 25 physicians and nurses working in hospitals and in 20 individuals working at radio-relay stations. Examination was conducted by chromosome aberration analysis of peripheral blood lymphocytes. The data showed that total number of chromosome aberrations in people exposed to ionizing and radio-frequency radiation (4.08 +/- 0.37 and 4.35 +/- 0.5 on 200 scored metaphases, respectively) were almost equally higher than those of non-irradiated subjects. The increase was in proportion to the number of individuals having more that 5-aberration/200 metaphases. Acentric fragments comprised the most frequently seen type of aberration. The average numbers in examined groups (11.8 x 10(-3) and 14.8 x 10(-3) per cell, respectively), were significantly higher than 4.2 x 10(-3), which was observed in controls, unexposed individuals. Dicentric fragments were also frequent (4.8 x 10(-3) and 6.25 x 10(-3), respectively, vs. 0.52 x 10(-3) in control). In contrast, the frequency of chromatid breaks increased only after ionizing radiation (3.8 x 10(-3) vs. 0.26 x 10(-3) in control). A positive correlation between the total number of chromosome aberrations and cumulative 6-years dosage was also found. The data emphasized the dangerous effects of prolonged exposure to both types of radiation and indicated that chromosomal aberration analysis should be obligatory for individuals working at radio-relay stations.</p

Picosecond Laser Ablation of Silicon Single Crystal in a Liquid Environment

The picosecond Nd:YAG laser at wavelengths of 1064 nm was used to produced the silicon-based nanoparticles in de-ionized water. The main goal of our work presented here was enlight the role of thermal effects on the process of laser ablation of solid target in liquid. To accieve this goal the additional heating of the target surface by continuous laser was applied during the experiment. The shift of nanoparticles size distribution caused by applying of additional continuous laser was reported in this work. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3492

Multiplication of microbes below 0.690 water activity: implications for terrestrial and extraterrestrial life

Since a key requirement of known life-forms is available water (water-activity; aw), searches for signatures of past life in terrestrial and extraterrestrial environments have recently targeted places known to have contained significant quantities of biologically available water. The lower limit of water activity that enables cell division is ~0.605 which, until now, was only known to be exhibited by a single eukaryote; the sugar-tolerant, fungal xerophile Xeromyces bisporus. The first forms of life on Earth were, however, prokaryotic. Furthermore, early life on Earth inhabited high-salt environments, suggesting an ability to withstand low water activity. Recent evidence indicates that some halophilic Archaea and Bacteria have water activity limits more or less equal to those of X. bisporus. Regardless of species, cellular systems are sensitive to minute differences in water activity (of w-units) so there is a need to determine water-activity values to three decimal places. We discuss water activity in relation to the limits of Earth’s present-day biosphere; the possibility of microbial multiplication by utilizing water from thin, aqueous films or non-liquid sources; whether prokaryotes were the first organisms able to multiply at the 0.605-aw limit; and whether extraterrestrial aqueous milieu of ≥0.605 aw can resemble fertile microbial habitats found on Earth

Interaction of ruby laser with carbon fibrous materials

Carbon fibrous materials are interesting because of their good properties and numerous possible applications. The characteristics of these materials can be programmed by careful selection of the modification process parameters. The laser technique can be successfully employed for these purposes. The high temperatures arising in the material during a short laser pulse can cause a number of changes in the material. Carbon fibrous materials with different textile shapes, during different stages of processing, were exposed to laser radiation. A ruby laser (lambda=694.3 nm) was used to modify the material. The structural changes were examined by scanning electron microscopy and Xray diffraction. It way established that the radiation of this laser induces structural changes leading to a better arrangement of the turbostratic carbon fiber structure.5th Young Researchers Seminar, Dec 25-26, 2006, Belgrade, Serbi

The Toxoplasma plant-like vacuolar compartment (PLVAC)

Toxoplasma gondii belongs to the phylum Apicomplexa and is an important cause of congenital disease and infection in immunocompromised patients. T. gondii shares several characteristics with plants including a nonphotosynthetic plastid termed apicoplast and a multivesicular organelle that was named the plant-like vacuole (PLV) or vacuolar compartment (VAC). The name plant-like vacuole was selected based on its resemblance in composition and function to plant vacuoles. The name VAC represents its general vacuolar characteristics. We will refer to the organelle as PLVAC in this review. New findings in recent years have revealed that the PLVAC represents the lysosomal compartment of T. gondii which has adapted peculiarities to fulfill specific Toxoplasma needs. In this review, we discuss the composition and functions of the PLVAC highlighting its roles in ion storage and homeostasis, endocytosis, exocytosis, and autophagy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/175241/1/jeu12951.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/175241/2/jeu12951_am.pd