962 resultados para Aggregate disruption


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"National Economics Division, Economics and Statistics Service, U.S. Dept. of Agriculture"--P. iii.

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"Prepared by Ronald L. Oaxaca ... and Carol A. Taylor."

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Mode of access: Internet.

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Mode of access: Internet.

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Previous research shows that correlations tend to increase in magnitude when individuals are aggregated across groups. This suggests that uncorrelated constellations of personality variables (such as the primary scales of Extraversion and Neuroticism) may display much higher correlations in aggregate factor analysis. We hypothesize and report that individual level factor analysis can be explained in terms of Giant Three (or Big Five) descriptions of personality, whereas aggregate level factor analysis can be explained in terms of Gray's physiological based model. Although alternative interpretations exist, aggregate level factor analysis may correctly identify the basis of an individual's personality as a result of better reliability of measures due to aggregation. We discuss the implications of this form of analysis in terms of construct validity, personality theory, and its applicability in general. Copyright (C) 2003 John Wiley Sons, Ltd.

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Options for skin cancer treatment currently include surgery, radiotherapy, topical chemotherapy, cryosurgery, curettage, and electrodes-sication. Although effective, surgery is costly and unsuitable for certain patients. Radiotherapy can leave a poor cosmetic effect, and current chemotherapy is limited by low cure rates and extended treatment schedules. Here, we describe the preclinical activity of a novel topical chemotherapeutic agent for the treatment of skin cancer, 3-ingenyl angelate (PEP005), a hydrophobic diterpene ester isolated from the plant Euphorbia peplus. Three daily topical applications of 42 nmol (18 mug) of PEP005 cured a series of s.c. mouse tumors (B16 melanoma, LK2 UV-induced squamous cell carcinoma, and Lewis lung carcinoma; it = >14 tumors/group) and human tumors (DO4 melanoma, HeLa cervical carcinoma, and PC3 and DU145 prostate carcinoma; it = >4 tumors/group) previously established (5-10 mm(3)) on C57BL/6 or Fox1(nu) mice. The treatment produced a mild, short-term erythema and eschar formation but, ultimately, resulted in excellent skin cosmesis. The LD90 for PEP005 for a panel of tumor cell lines was 180-220 muM. Electron microscopy showed that treatment with PEP005 both ill vitro (230 tot) and ill vivo (42 nmol) rapidly caused swelling of mitochondria and cell death by primary necrosis. Cr-51 release, uptake of propidium iodide, and staining with the mitochondria dye JC1, revealed that PEP005 (230 muM) treatment of tumor cells ill vitro resulted in a rapid plasma membrane perturbation and loss of mitochondrial membrane potential. PEP005 thus emerges as a new topical anti-skin cancer agent that has a novel mode of action involving plasma membrane and mitochondrial disruption and primary necrosis, ultimately resulting in an excellent cosmetic outcome.

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The efficiency of physical separation of inclusion bodies from cell debris is related to cell debris size and inclusion body release and both factors should be taken into account when designing a process. In this work, cell disruption by enzymatic treatment with lysozyme and cellulase, by homogenization, and by homogenization with ammonia pretreatment is discussed. These disruption methods are compared on the basis of inclusion body release, operating costs, and cell debris particle size. The latter was measured with cumulative sedimentation analysis in combination with membrane-associated protein quantification by SDS-PAGE and a spectrophotometric pepticloglycan quantification method. Comparison of the results obtained with these two cell debris quantification methods shows that enzymatic treatment yields cell debris particles with varying chemical composition, while this is not the case with the other disruption methods that were investigated. Furthermore, the experiments show that ammonia pretreatment with homogenization increases inclusion body release compared to homogenization without pretreatment and that this pretreatment may be used to control the cell debris size to some extent. The enzymatic disruption process gives a higher product release than homogenization with or without ammonia pretreatment at lower operating costs, but it also yields a much smaller cell debris size than the other disruption process. This is unfavorable for centrifugal inclusion body purification in this case, where cell debris is the component going to the sediment and the inclusion body is the floating component. Nevertheless, calculations show that centrifugal separation of inclusion bodies from the enzymatically treated cells gives a high inclusion body yield and purity. (C) 2004 Wiley Periodicals, Inc.

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Bloom syndrome and ataxia-telangiectasia are autosomal recessive human disorders characterized by immunodeficiency, genome instability and predisposition to develop cancer. Recent data reveal that the products of these two genes, BLM and ATM, interact and function together in recognizing abnormal DNA structures. To investigate the function of these two molecules in DNA damage recognition, we generated double knockouts of ATM(-/-) BLM-/- in the DT40 chicken B-lymphocyte cell line. The double mutant cells were viable and exhibited a variety of characteristics of both ATM(-/-) and BLM-/- cells. There was no evidence for exacerbation of either phenotype; however, the more extreme radiosensitivity seen in ATM(-/-) and the elevated sister chromatid exchange seen in BLM-/- cells were retained in the double mutants. These results suggest that ATM and BLM have largely distinct roles in recognizing different forms of damage in DNA, but are also compatible with partially overlapping functions in recognizing breaks in radiation-damaged DNA.

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In this paper, we report data drawn from a larger project on the functioning of the Queensland community service delivery system, particularly that providing services to people with disabilities. Our reasoning for focusing at this level is that, from the service user's perspective, support is derived from the service delivery system, not just individual service providers. Defining the service delivery system as formal services and informal support networks, we undertook interviews and focus groups with service providers in six areas in Queensland: inner urban, outer urban, rural and remote. The period on which we report is one in which considerable reform activity had been undertaken by funding bodies of the Commonwealth and State governments. We report on those factors we identified which promote the integrated functioning of the service delivery system, as well as those factors that disrupt it. We conclude with a brief evaluative analysis of the current status of the system.

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In this paper, we assess the relative performance of the direct valuation method and industry multiplier models using 41 435 firm-quarter Value Line observations over an 11 year (1990–2000) period. Results from both pricingerror and return-prediction analyses indicate that direct valuation yields lower percentage pricing errors and greater return prediction ability than the forward price to aggregated forecasted earnings multiplier model. However, a simple hybrid combination of these two methods leads to more accurate intrinsic value estimates, compared to either method used in isolation. It would appear that fundamental analysis could benefit from using one approach as a check on the other.