Linear time algorithm for finding a picture''s connected components

An algorithm that identifies the connnected components of a thresholded digitized picture is presented. The time complexity of the algorithm is linear in the number of runs of object pixels in the picture.     

Determination of antioxidative potential of biological fluids by using semiconductor chemical sensors

A procedure has been developed for determining the concentrations of superoxide anion radical (SOAR) in aprotonic fluids by using semiconductor chemical sensors. SOAR life in pure solutions is 6.3 hours. Supplements of biological fluids (blood, urine, plasma) increase the rate of SOAR death. There is a great difference in the reaction rate of SOAR with biological fluids in apparently healthy and ill individuals. It is suggested that the above procedure opens vistas both for studies of vital activity and for diagnosis of abnormalities.     

The secondary structure of amides of adenylic acid containing D- and L-aromatic amino acids

Adenylyl-(5'leads to N)-amino acids containing as amino components, methyl esters of D-, L- and DL-phenylalanine, D-, L- and DL-tyrosine, and D-, L- and DL-tryptophan have been investigated by proton magnetic resonance (PMR) spectroscopy and circular dichroism (CD). The temperature and pD dependences of proton chemical shifts of these compounds have been studied. These data, together with the magnitudes of the upfield chemical shifts of the PMR signals of adenine and aromatic amino acids residues in adenylyl-(5'leads to N)-amino acids, have enabled us to construct conformational models of these compounds. The proposed conformation has been substantiated by the CD results. It is shown that in adenylyl-(5'leads to N)-amino acids the planes of adenine and amino acid aromatic moieties are roughly parallel. The aromatic rings of phenylalanine and tyrosine are localized approximately above the centre of adenine. In adenylyl-(5'leads to N)-D, -(L)-tryptophan, the six-membered rings of the indole overlaps the five-membraned ring of adenine indole partially overlaps the six-membered ring of adenine. A difference in the non-covalent interactions of D- and L-amino acids with nucleotides has been revealed. The mutual localization of the aromatic systems of AMP and the amino acids and also the positions of -OCH3 group with respect to the centre of the amino acid aromatic moiety differs in the series of the studied nucleotide derivatives of D- and L-amino acids.     

Inversion of the substrate specificity of yeast alcohol dehydrogenase

The relationship between the size of the substrate binding pocket and the catalytic reactivities with varied alcohols was studied with the Saccharomyces cerevisiae alcohol dehydrogenase I (ScADH) and compared with the liver enzymes from horse (EqADH, EE isoenzyme) and monkey (MmADH alpha, alpha-isoenzyme). The yeast enzyme is most active with ethanol, and its activity decreases as the size of the alcohol is increased, whereas the activities of the liver enzymes increase with larger alcohols. The substrate pocket in ScADH was enlarged by single substitutions of Thr-48 to Ser (T48S), Trp-57 to Met (W57M), and Trp-93 to Ala (W93A), and a double change, T48S:W93A, and a triple, T48S:W57M:W93A. The T48S enzyme has the same pattern of activity (V/K) as wild-type ScADH for linear primary alcohols. The W57M enzymes have lowered reactivity with primary and secondary alcohols. The W93A and T48S:W93A enzymes resemble MmADH alpha in having an inverted specificity pattern for primary alcohols, being 3- and 10-fold more active on hexanol and 350- and 540-fold less active on ethanol, and are as reactive as the liver enzymes with long chain primary alcohols. The three Ala-93 enzymes also acquired weak activity on branched chain alcohols and cyclohexanol.     

后RoHS时代企业的应对方案(下)

(继接本刊2008年第21期第24页)2.4化学物质的控制化学物质的控制,还要和其他的要求结合在一起,还应该考虑材料或者产品的可靠性,应该和安规认证(如GS/CE/UL/VDE/NF等)结合在一起;除了要注意禁     

Radionuclides in the Kara sea bottom sediments

The contents and distribution of natural (214Pb, 214Bi, 228Ac, and 208Tl) and technogenic (90Sr, 137Cs, and 60Co) radionuclides in the Kara Sea bottom sediments was analyzed by using the materials collected by R/V "Pomor" (Murmansk Marine Biological Institute). In 1994, no high (critical) concentrations of technogenic radioisotopes were found in the sea sediments, while the spots (regions) of elevated 137Cs content found in 1984 were not confirmed in 1994. It was proposed that the main sources of entry of technogenic radionuclides in the sea sediments in the last years are the flow of the Ob'-Yenisei waters and container burials of radioactive waste in the sea, which appeared to have been markedly corroded. The latter is confirmed by detection in some places of 60Co, which was not previously found in the sediments.