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1.
Sphaerotilus natans is a sheathed bacterium existing in the activated sludge of wastewater treatment plants. IT is one of the filamentous bacteria causing the bulking and foaming difficulties of activated sludge. Isolating the strain and culturing it in an axenic environment could not only provide the metabolic knowledge of the strains that would be useful in the development of wastewater treatment methods, but also could enable us to gain an understanding of the mechanism by which poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (poly[3-HB-co-3-HV]) is produced by this strain. This article reports the screening and isolation of the strain from the activated sludge using the Nile blue staining method together with Fourier transform infrared analysis. We investigated the ability of the selected strain to produce poly(3-HB-co-3-HV) copolymer using glucose and peptone, or by adding valeric acid or sodium propionate as precursor. Proper precursor feeding could dramatically enhance its 3HV content in the copolymer P(3HB-co-3HV). By controlling the different feeding times in fed-batch fermentation, different desired copolymers were obtained with 15, 40, and 70% 3HV mole fraction of the copolymer. Polymer properties were analyzed by gas chromatography, differential scanning calorimetry, thermo-gravimetry, and nuclear magnetic resonance analysis. Open laboratory of Chirotechnology of the Institute of Molecular Technology for Drug Discovery and Synthesis The University Grants Committee Area of Excellence Scheme (Hong Kong).  相似文献   

2.
Garlicnin A (1), a new stable, sulfur-containing compound isolated from a fraction of the acetone extracts of Allium sativum L. garlic bulbs, showed the potential to suppress tumor cell proliferation by inhibiting the polarization of M2 alternatively activated macrophages, and its structure was characterized as 3,4-dimethyl-5-(4,5-dithia-1E,7-octadiene)-tetrahydrothiophene-2-sulfoxide-S-oxide, on the basis of the results of spectroscopic analysis results.  相似文献   

3.
From the fruiting bodies of Dictyostelium polycephalum, we obtained four aromatic compounds: dictyobiphenyl A (1) and B (2) and dictyoterphenyl A (3) and B (4). The synthesis of 14 was performed to confirm the structures and obtain sufficient material for biological evaluation. Compound 3 was the first example of nitrogen-containing natural m-terphenyls, and the isolation of novel classes of compounds such as 3 shows that cellular slime molds are promising sources in natural product chemistry. Moreover, dictyoterphenyl A (3) showed cancer cell-selective antiproliferative activity (IC50 2.3–8.6 μM).  相似文献   

4.
New hydrofining catalysts based on molybdenum, nickel, and aluminum nitride nanopowders produced by electrical explosion are obtained. Their physicochemical properties are studied. The direct sulfurizing of molybdenum nanopowders with sulfides from straight-run diesel oil fraction is shown to be possible. The high hydrodesulfurization capability of nanopowder catalysts is established.  相似文献   

5.
Kalimeris indica (L) Sch-Bip is a medicinal plant used by the Miao ethnic group in the Guizhou province of China. It is widely used as a fresh vegetable to treat colds, diarrhea and gastric ulcers. However, few studies have been conducted on the mechanism of its effect on colds, and its quality control. The anticomplement and antitussive activities of different polar extracts of K. indica were evaluated. Fifty-nine compounds, mainly including phenols and flavonoids, were identified in K. indica extract by ultra-high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry. A method was established through ultra-high-performance liquid chromatography with a photodiode array to simultaneously determine the anticomplement and antitussive activity of five compounds in K. indica combining chemical identification with chemometrics for discrimination and quality assessment. Also, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid exhibited significantly higher anticomplementary activity than the other three compounds. The quantitative data were further analyzed by principal component analysis and orthogonal partial least-squares discriminant analysis. Heatmap visualization was conducted to clarify the distribution of the major compounds in different geographical origins. Screening pharmacological activities by a combination of chemometrics and chemical identification might be an effective method for the quality control of K. indica.  相似文献   

6.
从中/低温煤焦油中切取重组分,提取了重组分C7-沥青质,并以此重组分为原料进行了高压釜加氢实验,通过1H-NMR、XRD、FT-IR、SEM、元素分析和相对分子量测定等手段对重组分沥青质结构参数、官能团、表观形态等方面进行了分析,并将其与加氢过程中生焦情况进行了关联。结果表明,C7-沥青质基本结构单元以稠环芳烃为中心,周围分布少而短的侧链,侧链以小于3个碳的短直链正构烷基为主,相对分子量小,芳香片层没有堆积结构。O是该沥青质中氢键主要来源,大多分布在环氧烷烃和醚类结构中,外围的O数量低,分子间氢键更难形成,结构单元之间缔合性弱,沉积聚合慢而均匀。沥青质中短侧链不易断裂,在反应过程中产生的稠环芳烃自由基少,缩合能力小,使该馏分油生焦能力低,具有较高的加氢潜质。  相似文献   

7.

Background

Anthropogenic activities introduce materials increasing levels of many dangerous substances for the environmental quality and being hazardous to human health. Major attention has been given to those elements able to alter the environment and endanger human health.The airborne particulate matter pollutant is considered one of the most difficult task in environmental chemistry for its complex composition and implications complicating notably the behavior comprehension. So, for investigating deeply the elemental composition we used two nuclear techniques, Neutron Activation Analysis and Photon Activation Analysis, characterized by high sensitivity, precision and accuracy. An important task has been devoted to the investigation of Quality Control (QC) and Quality Assurance (QA) of the methodology used in this study.This study was therefore extended as far back as possible in time (from 1965 until 2000) in order to analyze the trend of airborne concentration of pollutant elements in connection with the industrial and lifestyle growth during the entire period.

Results

Almost all the elements may be attributed to long-range transport phenomena from other natural and/or anthropogenic sources: this behavior is common to all the periods studied even if a very light decreasing trend can be evidenced from 1970 to 2002. Finally, in order to investigate a retrospective study of elements in PM10 and their evolution in relationship with the natural or anthropogenic origins, we have investigated the Enrichment Factors. The study shows the EF trends for some elements in PM10 during four decades.

Conclusions

The two nuclear techniques have allowed to reach elevated sensibility/accuracy levels for determining elements at very low concentrations (trace and ultra-trace levels). The element concentrations determined in this study do not basically show a significant level of attention from a toxicological point of view.
  相似文献   

8.
Brief history and current status of activation analysis in Korea are described. About 120 papers have been published since the first paper was reported in 1960. They are sorted out into 5 consecutive periods according to the publication year, and typical feature of each period is described.  相似文献   

9.
Obrunsník I  Adámek A 《Talanta》1968,15(5):433-440
A new method based on the substoichiometry principle has been developed. Instead of substoichiometric amounts of chelating agent, substoichiometric amounts of aqueous solution of a competing metal are used. Theoretical relationships have been derived for this method of substoichiometric replacement. Possibilities for its application are discussed.  相似文献   

10.
Reaction rate constants have been measured for the oxidation of cholesterol by atmospheric oxygen in the presence of tetra-meso-substituted metalloporphyrins [MP] (M = Ni, Cr, Mn, Fe, Co). The results have been interpreted by the use of data on the structure of metal complexes and reaction mechanisms. It has been established that the reaction proceeds at a high rate when the oxygen in the composition of the intermediate complex [MO2P] is in the singlet spin state. The singlet state of O2 is occupied in the case in wich the metal ion in the porphyrin complex is in a high-spin state. The spin state and related catalytic activity of the metalloporphyrin is regulated by meso-substituents in the porphine ring. The influence of meso-substituents is predicted theoretically within the framework of a generalized orienting effect, the presence of which is supported by an analysis of 13C NMR data for meso-substituted metalloporphyrins.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 4, pp. 428–435, July–August 1987.  相似文献   

11.
The amounts of protein and the activities of the proteinase (trypsin) inhibitors of 16 varieties of pea have been studied. The amount of protein ranged from 19.3 to 25.2% and the amidase activities of the trypsin inhibitors from 18 to 40.8 IU. It was found that the electrophoretic spectrum of the inhibitor-containing fraction of the pea seed protein consisted of 12–16 components with molecular masses of 14–89 kDa. Features of the electrophoretic spectrum of some varieties of pea have been established.V. F. Kuprevich Institute of Experimental Botany, Belorussian SSR Academy of Sciences, Minsk. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 243–247, March–April, 1989.  相似文献   

12.
Neutron activation analysis (NAA), along with multivariate statistical methods, were employed as a proposed method to measure concentrations of some 30 elements in filtered air particulates and to estimate the fraction of particulate matter originating from crustal sources. The new method may provide a means for certain agricultural industries, in particular cattle feedlots, to take advantage of the proposed crustal credit in emission regulations, if such a credit is implemented by the US Environment Protection Agency (EPA). Chemical composition of particulate source materials as well as environmental air particulate samples were determined and results compared using computer modelling techniques to determine contribution from each potential source.  相似文献   

13.
We investigated the constituents of Dictyostelium discoideum to clarify the diversity of secondary metabolites of Dictyostelium cellular slime molds and to explore biologically active substances that could be useful in the development of novel drugs. From a methanol extract of the multicellular fruit body of D. discoideum, we isolated two novel amino sugar analogues, furanodictine A (1) and B (2). They are the first 3,6-anhydrosugars to be isolated from natural sources. Their relative structures were elucidated by spectral means, and the absolute configurations were confirmed by asymmetric syntheses of 1 and 2. These furanodictines potently induce neuronal differentiation of rat pheochromocytoma (PC-12) cells.  相似文献   

14.
An antioxidant activity of indapamide (IDP) and its metabolite (OH-IDP) is demonstrated in this study. Both IDP and OH-IDP were found to scavenge 1,1-diphenyl-2-picryl-hydrazyl free radical. The scavenging effect of OH-IDP was stronger than that of IDP. Lipid peroxidation of rat liver microsomes initiated by reduced nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine diphosphate (ADP)-Fe3+ was inhibited by IDP and OH-IDP with IC50 values of about 6 and 2 microM, respectively. The lipid peroxidation in human erythrocyte membrane, induced by 2,2'-azobis-(2-amidinopropane dihydrochloride) treatment, was also inhibited by 10 microM IDP. The antioxidant capacity of OH-IDP was at almost the same level as that of alpha-tocopherol, tested for comparison. The present data show that IDP and OH-IDP at micromolar concentrations are able to trap the free radicals involved in the lipid peroxidation.  相似文献   

15.
This review of the literature and of the authors' own investigations is devoted to the biological activity of gossypol and its derivatives. Certain results of the structural—functional analysis of gossypol ethers and the products of its condensation with amines and CH-acids are discussed. The results of pharmacokinetic investigations of radioactively labeled samples of gossypol and its physiologically active derivatives are given.A. S. Sadykov Institute of Bioorganic Chemistry of the Academy of Sciences of the Uzbekistan Republic, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 334–349, May–June, 1993.  相似文献   

16.
This review of the literature and of the authors' own investigations is devoted to the biological activity of gossypol and its derivatives. Certain results of the structural—functional analysis of gossypol ethers and the products of its condensation with amines and CH-acids are discussed. The results of pharmacokinetic investigations of radioactively labeled samples of gossypol and its physiologically active derivatives are given.  相似文献   

17.
Antitumor activity of shikonin and its derivatives   总被引:11,自引:0,他引:11  
  相似文献   

18.
Non-destructive neutron activation analysis, employing a high-resolution Ge(Li) detector, was applied to determine the concentration of 24 trace elements in the tobacco of the Zarrin cigarette which is commercially made in Iran. These elements are: Na, K, Sc, Cr, Mn, Fe, Co, Zn, Se, Br, Rb, Ag, Sb, Cs, Ba, La, Ce, Sm, Eu, Tb, Hf, Au, Hg and Th. The smokes from the combustion of this tobacco and of the cigarette paper were also analysed for these elements and the percentage transference values were calculated.  相似文献   

19.
The influence of mechanical activation on the structure and catalytic activity of MoO3 was studied. It was established that as a result of mechanical treatment grinding, secondary aggregation of particles and accumulation of materials from the grinding machine occurred. An increase in the catalytic activity was observed in the oxidation of methanol to formaldehyde.  相似文献   

20.
The concentration of 28 elements in tobacco and cigarette paper in an Egyptian Cigarette were determined using instrumental neutron activation analysis. These elements are: Al, As, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mg, Mn, Na, Ni, Rb, Sb, Sc, Se, Sr, Th, Ti, V and Zn. The cigarette filter (before and after normal smoking) and the produced ash were analyzed to determine the adsorption of the elements on the filter and their remains in ash. The material balance for the determined elements were calculated.  相似文献   

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