A novel implementation technique of the information-theoretic approach to the independent component analysis problem is devised. This new algorithm uses the mixtures of densities as flexible models ...for the density functions of the source signals and they are tuned adaptively to approximate the marginal densities of the recovered signals. We suggest that the adaptive, flexible models for the density functions have the advantage that they can adapt source signals with any distribution, while pre-selected, fixed models, which appear as fixed nonlinearities in the algorithm, may only work on source signals with a particular class of distribution. Experiments have demonstrated the above assertions.
To evaluate the technique of native collagen fluorescence imaging for assessing the extent of welded areas for tissues exposed to different near-infrared (NIR) laser wavelengths.
Native fluorescence ...imaging may be used to identify the distribution of collagen and elastin in tissues. Our past work demonstrated that different welding strengths were obtained under the same laser power conditions using different NIR wavelengths. The role of collagen in tissue welding experiments is not well understood.
Two new NIR tunable lasers were used to weld canine skin. The welded areas on the surface and in cross sections were analyzed by measuring the spatial distribution of native collagen fluorescence at 380 nm excited by 340 nm radiation.
The results show that native collagen fluorescence imaging is a useful technique for analyzing the extent of tissue welds produced under a range of laser exposures. Fluorescence imaging reveals the depth of laser interaction with the tissue as well as evaluating collateral damage to the tissue surface. The welded volume obtained in skin using Cunyite laser exposure at 1,430 nm is deeper than that produced with Forsterite laser exposure at 1,250 nm. The post welded tensile strength for the same power density is greater for the Cunyite lasers. Ablated tissue on the surface is more prevalent with Forsterite laser welding at 1,250 nm than with Cunyite at 1,430 nm.
Native collagen fluorescence can distinguish between tissue welds that have been produced by different NIR wavelengths. Tissue welding using 1,430 nm radiation is more effective than that using 1,250 nm.
A clonal assay to determine the mutant frequency (MF) at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus in human lymphocytes has been used by a number of investigators to study ...exposure to mutagens and carcinogens in a variety of populations. We have studied hprt MF in 106 subjects (40 controls and 66 cases) enrolled in a case-control investigation of lung cancer. Epidemiological data collected included smoking history, intake of dietary micronutrients, and occupational and environmental exposures as well as medical history, all obtained from an interviewer-administered questionnaire. All subjects were also genotyped for the known polymorphism in glutathione S-transferase class mu (GST-mu). In analysis of cases and controls, hprt MF was not associated with age, smoking, the polymorphism in GST mu, dietary intake, occupational exposures, family history of cancer or usage of medications. Since MF and cloning efficiency (CE) are not independent when CE is low, further analysis in cases and controls with a CE greater than or equal to 30% (27 cases and 22 controls) was also conducted. In analysis of controls, hprt MF increased with age and was inversely associated with intake of folate and vitamins A and C. The presence of lung cancer was not associated with hprt MF. Thus, our study supports the previous observation that dietary components may affect the MF at the hprt locus.
The Argo profiling float project will enable, for the first time, continuous global observations of the temperature, salinity, and velocity of the upper ocean in near‐real time.This new capability ...will improve our understanding of the ocean's role in climate, as well as spawn an enormous range of valuable ocean applications. Because over 90% of the observed increase in heat content of the air/land/sea climate system over the past 50 years occurred in the ocean Leuitus et al., 2001, Argo will effectively monitor the pulse of the global heat balance.The end of 2003 was marked by two significant events for Argo. In mid‐November 2003, over 200 scientists from 22 countries met at Argo's first science workshop to discuss early results from the floats. Two weeks later, Argo had 1000 profiling floats—one‐third of the target total—delivering data. As of 7 May that total was 1171.
Two functional cytosolic thymidine kinase (tk) cDNA clones were isolated from a mouse L-cell library. An RNA blot analysis indicated that one of these clones contains a nearly full-length tk sequence ...and that LTK
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cells contain little or no TK message. The nucleotide sequences of both clones were determined, and the functional mouse tk cDNA contains 1,156 base pairs. An analysis of the sequence implied that there is an untranslated 32-nucleotide region at the 5′ end of the mRNA, followed by an open reading frame of 699 nucleotides. The 3′ untranslated region is 422 nucleotides long. Thus, the gene codes for a protein containing 233 amino acids, with a molecular weight of 25,873. A comparison of the coding sequences of the mouse tk cDNA with the human and chicken tk genes revealed about 86 and 70% homology, respectively. We also isolated the tk gene from a mouse C57BL/10J cosmid library. The structural organization was determined by restriction mapping, Southern blotting, and heteroduplex analysis of the cloned sequences, in combination with a mouse tk cDNA. The tk gene spans approximately 11 kilobases and contains at least five introns. Southern blot analysis revealed that this gene is deleted in mouse LTK
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cells, consistent with the inability of these cells to synthesize TK message. This analysis also showed that tk-related sequences are present in the genomes of several mouse strains, as well as in LTK
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cells. These segments may represent pseudogenes.
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