人类活动影响下新疆生态环境的一些变化

人类活动引起的新疆生态环境变化主要有以下几方面:1.河流流程缩短,河水矿化度和泥沙含量增加;2.湖泊水位下降,湖面缩小或变干,湖水矿化度升高;3.森林破坏,面积缩小;4.草场的产草量降低,牧草质量下降; 5.土壤次生盐渍化、沼泽化和肥力下降;6.土地沙漠化不断扩大。     

Characteristics of Symmetric Surface Plasmon Polariton Mode in Glass–Metal–Glass Waveguide

The propagation characteristics of symmetric surface plasmon polariton mode in a glass–metal–glass waveguide are presented. Gallium lanthanum sulfide has been taken as the glass and silver (Ag) has been used as the metal. The analysis has been done both numerically and analytically. A two-dimensional finite-difference time-domain-based simulation model has been developed in order to analyze the propagation characteristics numerically. The obtained results using numerical and analytical methods have been compared and a very good agreement has been found.     

Imaging erythrocytes under physiological conditions by atomic force microscopy

Since its invention in the mid 1980s atomic force microscopy has revolutionised the way in which surfaces can be imaged. Close to atomic resolution has been achieved for some materials and numerous images of molecules on surfaces have been recorded. Atomic force microscopy has also been of benefit to biology where protein molecules on surfaces have been studied and even whole cells have been investigated. Here we report a study of red blood cells which have been imaged in a physiological medium. At high resolution, the underlying cytoskeleton of the blood cell has been resolved and flaws in the cytoskeleton structure may be observed. Comparison of the normal 'doughnut' shaped cells with swollen cells has been undertaken. Differences in both the global properties of the cells and in the local features in cytoskeleton structure have been observed.     

A quantitative assay for total fructans in burdock (Arctium spp.) roots

A quantitative assay of the total content of polysaccharides (fructans) in burdock roots in fructose equivalent has been elaborated. Extraction of free carbohydrates and polysaccharides has been studied using spectrophotometry and quantitative HPTLC. The optimal parameters for extracting the target group of compounds have been determined. Metrological analysis of the elaborated assay has been performed. It has been shown that the detection error does not exceed 3%.     

Melanocyte-directed enzyme prodrug therapy (MDEPT): development of a targeted treatment for malignant melanoma.

A novel prodrug rationally designed to function as a tyrosinase substrate has been synthesised to allow targeted treatment of malignant melanoma. This agent has been evaluated for tyrosinase-mediated drug release, and has been shown to act in the desired manner. Furthermore, differential cytotoxicity has been demonstrated in cell lines which express tyrosinase and those which do not.     

Purification and substrate specificity of BcmI restriction endonuclease

A strain producing the new specific restriction endonuclease BcmI has been found in the Bacillus generum. The enzyme has been purified by chromatography on the blue sepharose, phosphocellulose PII, heparin sepharose. The analogous purification has been obtained when the blue sepharose has been substituted for the orange sepharose, the home produced sorbent. The BcmI enzyme has been shown by the substrate specificity definition to be an isoschizomer of the restriction endonuclease ClaI.     

Photomyoclonic seizures in the baboon, Papio papio.

The inborn seizure response of Papio papio to intermittent light stimulation has been reviewed as a model of human epilepsy. The electrographic and clinical features have been described and useful methodology has been outlined. A diurnal cyclicity in seizure responsiveness has been described with greatest seizure severity at 8 AM in parallel with a rise in urinary output of cortisol. Hormonal influences on the seizure response have been described for ethinyl estradiol, thyroxin, and triiodothyronine. Evidence regarding neurotransmitter involvement has been reviewed. Data regarding use of the animal for anticonvulsant testing in single and chronic doses has been discussed. Particular advantages of the model for study of age-related drug effects and the assessment of the effects of chronically administered anticonvulsant agents on learning and memory have been described.     

Polymorphism of microsatellite DNA and study of maize genetic resources

Microsatellite loci PCR-analysis of 80 maize lines and hybrids from two regions of Ukraine has been carried out. Allelic sets individual for each maize genotype have been revealed and discrimination potential of applied marker system has been determined. Comparative analysis of frequencies of alleles and genotypes occurrence in both samples has been carried out and possible participation of the investigated SSR-loci in formation of maize adaptability system has been shown.     

Cloning, mapping and gene product identification of rhaT from Escherichia coli K12

Rhamnose utilization requires the function of a specific rhamnose transport system. Rhamnose transport mutants have been isolated and characterized. The structural gene, rhaT, encoding the rhamnose permease has been cloned from Escherichia coli. rhaT has been mapped in the rha locus (87.7 min) by analysis of cotransduction with glpK and other rha markers. The precise location of the gene has been determined by complementation analysis of rhamnose transport mutants transformed with recombinant plasmids containing different fragments of the cloned region. Gene order (counterclockwise) is established as glpK . . . rhaT-rhaR-rhaS-rhaB-rhaA-rhaD. The gene product has been identified by expression of rhaT in a T7 RNA polymerase/promoter system. This 23 kDa protein has been assigned to the rhaT product and has been shown to be located in the cell membrane.     

Shrubs of Vladivostok: Percentage in green plantings and resistance in urban ecosystems

Many years of study were devoted to fructicose flora of plantings in the city of Vladivostok. Species diversity bearing on the type of planting has been studied. Contribution of each species to the city’s landscaping has been assessed quantitatively. The vitality of shrubs has been diagnosed and their stability in the conditions of urban ecosystems has been estimated.     

Comparison of lipase-catalysed esterification in supercritical carbon dioxide and in n-hexane

Summary Oleic acid esterification by ethanol has been performed by an immobilized lipase fromMucor miehei in supercritical carbon dioxide and in n-hexane as solvents. In both media, determination of apparent kinetic constants has been achieved and influence of water content has been shown to be different due to various rates of water solubilities. Stability of the lipase has been proved to be correct and similar in both solvents. Inhibition by ethanol excess has been found but is greater in n-hexane. That can explain the higher initial velocities obtained in supercritical carbon dioxide for the highest ethanol concentrations.     

The effect of oligomycin on rat liver mitochondria respiring in state 4

It has been found that oligomycin inhibits up to at least 50% state-4 mitochondrial respiration. A time dependence of oligomycin inhibition has been shown. A titration curve for state-4 respiration of sigmoidal profile has been presented. The possibility of misreading this oligomycin effect, so far never reported, has been excluded by evaluating the quality of mitochondrial preparations used in respect to their morphological, functional and electrochemical properties. The conclusion has therefore been put forward that the most part of respiration in steady-state-4 is driven by ATP synthesis.     

Sampling Schemes for Studying Growth of Children

Efficiency of linked cross-sectional scheme has been compared with pure longitudinal schemes for generalised estimation of norm relaxing the condition of constancy of variances. The relevant theory of estimation has been developed and the expression for the optimum estimators alongwith their variances have been derived. The percentage gain in efficiency has been calculated. It has been observed that for higher values of Q, percentage gain in efficiency of proposed scheme over cross-sectional is very high.     

Light birefringence and molecular orientation in erythrocyte membranes and surface layers

The light birefringence in the surface layer of erythrocytes has been determined. A mathematical expression for the phase difference caused by birefringence in the spherical layer has been derived. Thickness of the anisotropic layer of erythrocytes has been evaluated. Birefringence in surface layers of erythrocytes has been shown to be caused not only by the membrane, but also by close to it structured proteins.     

Transmission acoustic microscopy of tissue sections (1 GHz). Histoacoustics and acoustic staining

The acoustic microstructure of mouse small intestine has been studied with a transmission acoustic microscope working at 1 GHz and the influence of the histologic processing on the microacoustic pattern has been tested. Unstained thin sections provide pictures rich in details and highly contrasted. Gelatin has been used as hydrosoluble embedding medium and has been compared to paraffin. The former embedding procedure retained the viscoelastic properties of the specimen far more and provided the most detailed pictures. Osmiun tetroxide has been used to demonstrate acoustic staining.     

3-acetyloleanolic acid from Phytolacca americana seeds

3-Acetyloleanolic acid has been obtained from the seeds of Phytolacca americana L. It has not been detected in other parts of the plant. Oleanolic acid has been detected in the roots.     

Sulfhydryl groups of cyclic AMP-dependent histone kinase from pig brain]

A preparative method of isolation of the histone kinase regulatory subunit has been developed. The total number of cysteine residues in the enzyme (13 residues) and in each of its subunits (3 residues in the catalytic subunit and 10 residues in the regulatory one), has been determined. Two disulfide bridges have been found in the regulatory subunits. The relative availability of the sulfhydryl groups with respect to different modifying agents has been studied. It has been demonstrated that SH-groups blocking does not change essentially the enzyme activity.     

Determination of amylase activity in bovine serum and its association with the Ami and Amll loci

Amylase activity has been estimated in the sera of 213 cattle by an amyloclastic method with potato amylose as the substrate with the addition of CaCl₂. The method has been developed from that of Street and Close to overcome the problems of the high colour of bovine serum which would otherwise interfere with the assay. A relationship has been found between the serum amylase genotype detected on starch-gel and the total enzyme activity. The enzymes AmI-B and AmII-B in homozygous combinations have been found to have the highest activities. Age of animal has no significant effect on the total enzyme activity. Activity has been investigated in sera from three separate cattle populations and it has been found to be a highly heritable character. Heritability estimates of 49 % and 39 % by sib analysis and 75 % by the twin method have been obtained.     

Transmission acoustic microscopy of tissue sections (1 GHz)

Summary The acoustic microstructure of mouse small intestine has been studied with a transmission acoustic microscope working at 1 GHz and the influence of the histologic processing on the microacoustic pattern has been tested. Unstained thin sections provide pictures rich in details and highly contrasted. Gelatin has been used as hydrosoluble embedding medium and has been compared to paraffin. The former embedding procedure retained the viscoelastic properties of the specimen far more and provided the most detailed pictures. Osmiun tetroxide has been used to demonstrate acoustic staining.     

Acute oxygen supply by infusion of hemoglobin solutions.

Preparations of 6% human hemoglobin have been investigated for 4 years. While the oxygen dissociation curve is shifted to the left, the hemoglobin solution has been shown to deliver oxygen adequately to the tissues in animal studies. Intracorporeal fate has been investigated by 131-I tagging, and the hemoglobin has not been found to accumulate in the tissues. Intravascular half-life has varied between 1.5 and 3.5 hours.