Masking device Patent

Reusable masking boot for chemical machining operation

Time Course of PR of UV-Induced Chromosomal Aberrations and Lethal Damage in G1 Xenopus Cells

Synchronous cultures of early G1 cells were exposed to UV and their ability to photoreactivate lethal and aberrational damage was determined as a function of time following UV exposure. Lesions leading to cell death were converted to a non-photoreactivable state before cells entered S phase, while lesions leading to chromosomal aberrations were converted to a non-photoreactivable state as the cells entered S phase. These results indicate that the intracellular mechanism which expresses photoreactivable UV-induced lesions in G1 cells as cell death is not identical to the mechanism which expresses such lesions as chromosomal aberrations, and the two mechanisms operate primarily in different phases of the cell cycle

Time Course of PR of UV-Induced Chromosomal Aberrations and Lethal Damage in S and G2 Xenopus Cells

Sand G2 phase cells were exposed to 150 ergs mm⁻² UV and their ability to photoreactivate the induced cell killing (loss of colony forming ability) and chromosomal aberrations was determined as a function of time following the UV exposure. In S phase cells, the lesions leading to cell death and those leading to aberrations were both converted to a non-photoreactivable state shortly after the UV exposure. A significant fraction of the lesions induced in G2 cells, that led to cell death, were converted to a non-photoreactivable state before the progeny of the exposed cells reached the next succeeding S phase. Few, if any, lesions were induced in G2 cells that were expressed as aberrations at the first mitosis following exposure. Some of the lesions induced in G2 cells led to aberrations that were observable in the progeny that progressed to the second mitosis following exposure. These lesions were converted to a nonphotoreactivable state as the progeny of the exposed G2 cells progressed through the first S phase following exposure

Study of Ultraviolet-Induces Chromatid and Chromosome Aberrations as a Function of Dose in G1 Phase Vertebrate Tissue Cultures

G1 phase A8 Xenopus laevis (toad) and V79B Cricetulus griseus (hamster) tissue cultures were used to observe the frequency of ultraviolet-induced chromosomal aberrations as a function of dose. When cultures are irradiated with ultraviolet light, visible aberrations are virtually absent until a threshold of approximately 80 ergs mm⁻¹ is reached. Aberrations then occur as a nonlinear function of dose. Chromatid aberrations are by far the most prevalent until doses in excess of 200 ergs mm⁻¹ are administered, at which point chromosome aberrations become common

Photoreactivation of Lethal Damage Induced in Hamster X Xenopus Hybrid Cells and Their Parentals by UV Light

A85 Xenopus cells that exhibited a high level of photoreactivation (PR) and V79B2 hamster cells that exhibited little PR were fused to produce the V79B2 x A85 cell line — a hybrid line which possessed a relatively stable karyotype, with most cells containing the entire V79B2 and A85 genomes. UV and UV plus PR fluence-survival relations were then determined and compared for the hybrid and parental lines in a first attempt to elucidate interactions of the parental PR mechanisms in the hybrid. It was anticipated that the A85 genome in the hybrid would produce PR enzyme in sufficient concentration and of such a nature as to efficiently PR UV-induced lethal damage in both A85 and V79B2 DNA, and little difference would be observed in the levels of PR exhibited by the V79B2 x A85 and A85 lines. To the contrary, the level of PR observed for the hybrid was substantially below that observed for the A85 line. To assist in the interpretation of this unexpected observation, three additional preliminary studies were carried out: 1) Comparison of the optimum PR schemes for the A85 and hybrid lines, 2) examination of relations between the PR and dark UV repair mechanisms possessed by these lines, and 3) comparison of the levels of PR of chromatid deletions induced by UV in selected V79B2 and A85 chromosomes of the hybrid. The results suggested that the relatively low level of PR manifested by the hybrid cells was a consequence of their inability to efficiently PR pyrimidine dimers induced by UV in V79B2 DNA

Fundamentals of Signal Processing Applied to Rotating Machinery Diagnostics

TutorialRotating machinery diagnostics have been, and will be, a critical area in the Oil and Gas Industry. Though in the early days oscilloscopes and spectrum analyzers were typically used to analyze vibration data, in recent years, technological advances in computers have made it possible to make use of them in solving machinery problems. However, it becomes critical to accept the fact that in order to manipulate vibration signals in a software environment, they have to be previously transformed into digital format. Even though information on the various signal processing techniques are readily available, most of the time, the manner in which this topic is discussed tends to be somehow theoretical. This tutorial intends to provide a summary of these techniques, but most importantly, the link between the basic theory and real applications. It also emphasizes how choosing the wrong parameters in the data acquisition device will definitely affect the quality of vibration data, critical to solving machinery problems

The Effects of a Perceptual-Motor Training Program on the Development of Motor Perception Skills on Kindergarten Children

The purpose of this study was to partially evaluate the effectiveness of a kindergarten perceptual-motor training program in regard to improvement of motor skills. In this evaluation the primary effort will be to measure those aspects of readiness which are closely related to the specific objectives of the perceptual motor training program. A secondary effort will be made to evaluate the general efforts of the training on aspects of readiness less closely related to the specific objectives of the program. The hypothesis upon which the present study is predicated is that there will be significant difference in motor perception skills of the kindergarten children participating in perceptual motor training when compared with kindergarten children participating in a regular physical education program. A second hypothesis was that the experimental group i.e., the motor perception group would be significantly different as tested by the Johnson Fundamental Skill Test

Mapping biodiversity value worldwide: combining higher-taxon richness from different groups

Maps of large-scale biodiversity are urgently needed to guide conservation, and yet complete enumeration of organisms is impractical at present. One indirect approach is to measure richness at higher taxonomic ranks, such as families. The difficulty is how to combine information from different groups on numbers of higher taxa, when these taxa may in effect have been defined in different ways, particularly for more distantly related major groups. In this paper, the regional family richness of terrestrial and freshwater seed plants, amphibians, reptiles and mammals is mapped worldwide by combining: (i) absolute family richness; (ii) proportional family richness; and (iii) proportional family richness weighted for the total species richness in each major group. The assumptions of the three methods and their effects on the results are discussed, although for these data the broad pattern is surprisingly robust with respect to the method of combination. Scores from each of the methods of combining families are used to rank the top five richness hotspots and complementary areas, and hotspots of endemism are mapped by unweighted combination of range-size rarity scores