Biomedical subjects

S Weng

Publications and source records attributed to S Weng.

At least 37 records · Page 2Linked to original sources

PubMed2000

[Effect of Al3+ on luminescence intensity of Tb in silica glasses].

The silica glasses doped with Tb3+ and Al3+ iones was synthesized through Sol-Gel process in this paper. The effect of Al3+ on luminescence properties of Tb3+ were studied. The results show that no obvious effect of Al3+ on the emission peak position of Tb3+, but the emission intensity of Tb3+ doped Al3+ by sol-gel process increased obviously for all samples. The emission intensity of 1% Al-99% SiO2 glass was 5 times larger than that of 100% SiO2 glass. We concluded that the relation between the energy levels of Tb3+ and the energy levels of Al3+ may be appropriate for the energy transfer, the function of Al3+ was to absorb efficiently energy and to transfer fully to Tb3+.

Aluminum↗

PubMed2000

[Influence on luminescence of Tb o-aminobenzolate complexes by second ligand].

Two Tb o-aminobenzolate complexes with different second ligands (phenanthroline and triphenyl phasphine oxide) were synthesized. Their structures and fluorescent properties were investigated by fluorescence spectroscopy and FTIR spectroscopy. The results indicate that the second ligand affected on the complexes luminescence by changing its structure.

Chelating Agents↗

PubMed2000

[FTIR study on the structures of bilirubin in solution].

The structures of bilirubin in solid-state, in HCCl3 and DMSO solution are investigated by FTIR spectroscopy. The results indicate that bilirubin have very different structures in solid-state and in solutions. The results also demonstrate that the structures vary in different solvents. There are six H-bonds in bilirubin molecule in solid-state, four in bilirubin molecule in HCCl3 solution and one in bilirubin molecule in DMSO solution.

Animals↗

PubMed2000

[The study of the microwave reaction of stearic acid and pentyl amine].

In this study, the microwave reaction of stearic acid and pentyl amine was investigated by FTIR spectroscopy. The results indicated that after mixing the two reactants together, pentyl ammonium stearate was created and it formed acid-salt structure with the stearic acid remained. The results also demonstrated that under microwave radiation, the pentyl ammonium stearate could be not only decomposed, but also dehydrated to form stearic pentyl amide. It suggested that the microwave radiation was an ideal technique to make this chemical reaction much faster and much more thorough.

Amines↗

PubMed2000

[FT-Raman spectroscopic investigation on stomach cancer].

FT-Raman spectroscopy was used to investigate 40 normal and malignant tissues from stomach. Statistic analysis shows that the bands related to OH, NH, C=O stretching and H-O-H bending are stronger in malignant tissues. This phenomenon suggests that the hydrogen bonding systems among water and protein vary in malignant tissues.

Humans↗

PubMed2000

[Luminescence enhancement of phthalate-Eu-Sr complex].

Using doped method low rare earth concentration and chelates matrix luminescence was successful in the chelates systems. The luminescence of phthalate-Eu-Sr complex is an example. The experimental results show that the complex luminescence would be enhanced co-doped other metal ions(shch as Mn), because other metal ions can transfer energy to rare earth ion. Addition of the second ligand will enhance the complex luminescence, too. In the FTIR spectra of co-doped complexes, the vibrations of nu a(COO-), nu as(COO-), nu CC have shifted, which show that the co-doped metal ions have influence on the molecular structure.

Chelating Agents↗

PubMed2000

[Orientation of H-bonds revealed by cryogenic FTIR spectroscopy].

We propose a new way to reveal structural arrangement of hydrogen bond network using FTIR spectroscopy. When KBr pellet and fluorolube mull methods are used to prepare samples for IR measurements, the resultant spectra sometimes show significant differences, sometimes not. The reason is unknown. We use cryogenic FTIR spectra to prove pressure effect accounts for spectral variation in different sampling process. The sensitivity of the FTIR spectra to external pressure is related to the three-dimensional arrangement of hydrogen bonding network in the sample. When hydrogen bonds are in one plane, they can not resist external pressure applied perpendicular to that plane. Consequently, large differences appear between the spectra obtained using KBr pellet and fluorolube mull methods. On the other hand, when hydrogen bonds orientate towards various directions, the hydrogen bonding system can resist pressure from any directions. Thus, the FTIR spectra exhibit little variation using different sampling methods. We propose that the spectral variation obtained using above methods is a criterion to judge whether the hyrogen bonds orientate toward various directions in three-dimensional space or not.

Cholesterol↗

PubMed2000

[Spectroscopic study on DL-homocysteic acid and it's complexes].

The main IR bands of the DL-Homocysteic acid was preliminary assigned. The complexes of DL-Homocysteic acid with Na+, K+, Ca2+ were synthesized. Element analysis and TGA-DTA were used to conclude the compositions of these complexes. The FTIR and FT-Raman spectra were studied to distinguish the different coordination structures. The bands of carboxyl, sulfonate and amino groups are all shifted. The peaks of-CH2- also changed a lot. The results indicated that the H-bonding structures among the moleculars were rearranged. The carboxyl and sulfonate groups of DLH both coordinated with the metal ions. And the coordination structure of C=O group in the three complexes were all monodentated.

Calcium↗

PubMed2000

[The FAR-IR study of several mono and disaccharides and metal-sugar complexes in solid state].

FIR spectra of saccharides have many peaks. Each saccharide has its characteristic spectrum. The first, the second, the third, the fourth strongest peak appear at different regions(a, b, c, d) and the sequence (the first in a, the second in b, the third in c, the fourth in d) is characteristic. Due to the sequence in relative intensity is different, we use a simple method encoding four strong peaks to distinguish between different saccharides. We divide 500-100 cm-1 into ten ranges and encode each region as follows: 1(100-140 cm-1); 2(141-180 cm-1); 3(181-220 cm-1); 4(221-260 cm-1); 5(261-300 cm-1); 6(301-340 cm-1); 7(341-380 cm-1); 8(381-420 cm-1); 9(421-460 cm-1); 0(461-500 cm-1). For example, the codes of xylose are 6,538 and the codes of d-arabinose are 7 486. Each saccharide has a number. In this way, we can easily differentiate between saccharides. When the complexes have formed, there are broad peaks of M-O. The phenomena illustrate that FIR technique is an useful mean to determine the formation of the complexes and possibly detect their structures.

Disaccharides↗

PubMed1999

Identification of a virulence-associated protein homolog gene and ISRa1 in a plasmid of Riemerella anatipestifer.

Riemerella anatipestifer is the causative agent of polyserositis of ducks and geese. We have previously reported that a 3.9-kb plasmid, pCFC1, carries protein genes (vapD1 and vapD2) that are similar to virulence-associated genes of other bacteria. In the present study, we report the complete sequence of a second plasmid of 5.6 kb, pCFC2. pCFC2 has a 28% G-C content and three large open reading frames (ORFs). One of the ORFs (designated asVapD1) encodes a polypeptide that shares 53.9, 53.9, 48.3, 48.3 and 46.1% identity with virulence-associated proteins of Dichelobacter nodosus, Actinobacillus actinomycetemcomitans, Neisseria gonorrhoeae, Helicobacter pylori and Haemophilus influenzae, respectively. The second ORF encodes a putative DNA replication protein (RepA3) with 309 amino acids and a molecular mass of approximately 36 kDa. A novel insertion sequence (IS) element, designated ISRa1, was found on the plasmid pCFC2. ISRa1 was flanked by 15-bp imperfect inverted repeats (only one mismatched nucleotide). ISRa1 contained an ORF encoding a putative transposase of 292 amino acids. Southern blot analysis indicated that in R. anatipestifer strains examined, ISRa1 was present with 2-20 copies (at least). ISRa1 displayed a sequence approximately 35% homologous to the putative IS982 and RSBst-alpha from Lactococcus lactis ssp. cremoris SK11 and Bacillus stearothermophilus CU21. Three hybridization patterns of genomic DNA of eight R. anatipestifer strains with an ISRa1 probe indicated that ISRa1 might be a useful tool for epidemiological studies.

Amino Acid Sequence↗

PubMed1999

Using the Saccharomyces Genome Database (SGD) for analysis of protein similarities and structure.

The Saccharomyces Genome Database (SGD) collects and organizes information about the molecular biology and genetics of the yeast Saccharomyces cerevisiae. The latest protein structure and comparison tools available at SGD are presented here. With the completion of the yeast sequence and the Caenorhabditis elegans sequence soon to follow, comparison of proteins from complete eukaryotic proteomes will be an extremely powerful way to learn more about a particular protein's structure, its function, and its relationships with other proteins. SGD can be accessed through the World Wide Web at http://genome-www.stanford.edu/Saccharomyces/

Computational Biology↗

PubMed1999

Unified display of Arabidopsis thaliana physical maps from AtDB, the A.thaliana database.

In the past several years, there has been a tremendous effort to construct physical maps and to sequence the genome of Arabidopsis thaliana. As a result, four of the five chromosomes are completely covered by overlapping clones except at the centromeric and nucleolus organizer regions (NOR). In addition, over 30% of the genome has been sequenced and completion is anticipated by the end of the year 2000. Despite these accomplishments, the physical maps are provided in many formats on laboratories' Web sites. These data are thus difficult to obtain in a coherent manner for researchers. To alleviate this problem, AtDB (Arabidopsis thaliana DataBase, URL: http://genome-www.stanford.edu/Arabidopsis/) has constructed a unified display of the physical maps where all publicly available physical-map data for all chromosomes are presented through the Web in a clickable, 'on-the-fly' graphic, created by CGI programs that directly consult our relational database.

Arabidopsis↗

PubMed1999

Inhibition of arterial thrombus formation by ApoA1 Milano.

The mutant form of human apoA1, known as apoA1 Milano, is formed as a result of arginine 173 to cysteine substitution and inhibits experimental atherosclerosis in cholesterol-fed animals. This study was designed to determine if apoA1 Milano would modify arterial thrombogenesis. Sprague Dawley rats were intravenously administered the carrier alone (n=8) or apoA1 Milano (20 mg. kg-1. d-1 for 4 to 10 days, n=17). The abdominal cavity was opened, and the abdominal aorta was isolated. Whatman paper impregnated with 35% FeCl3 was wrapped around the surface of the aorta, and aortic flow was recorded continuously. In carrier-treated rats, an occlusive platelet-fibrin-rich thrombus was formed in 21.2+/-4.1 (mean+/-SD) minutes. Treatment of rats with apoA1 Milano markedly delayed time to thrombus formation (38.8+/-11.9 versus 21.2+/-4.1 minutes, P<0. 01), inhibited platelet aggregation (25+/-7% versus 50+/-11%, P<0. 01), and reduced weight of the thrombus (18.5+/-1.8 versus 23.7+/-2. 3 mg/cm, P<0.01). Total cholesterol and HDL levels remained similar in both groups of rats, but plasma apoA1 Milano levels were elevated in apoA1 Milano-treated rats. In in vitro studies, incubation of platelets with apoA1 Milano reduced ADP-induced platelet aggregation by about 50%, but apoA1 Milano had no direct effect on vasoreactivity. This study provides further evidence for critical role of platelets in thrombosis. Use of apoA1 Milano offers a novel approach to inhibit arterial thrombosis.

Animals↗

PubMed1999

[Comparison of subclinical infection rates between vaccinated group with type I inactivated vaccine against hemorrhagic fever and controls].

OBJECTIVE: To compare subclinical infection rate in the vaccinated group with type I inactivated vaccine against hemorrhagic fever with renal syndrome (HFRS) with that in the controls and to understand its enhancement. METHODS: A trial field was selected in Jiande County, Zhejiang Province during July 1974 to November 1997. Paired-sera before and after vaccination were collected from 401 vaccinee and 360 controls, respectively. Serum titer of indirect immunofluorescent IgG antibody (IFAT) against HFRS was detected for each of them, and its cut-off value depended on the distribution of serum antibody titer in the second determination in the controls, which could be used to evaluate subclinical infection before vaccination. RESULTS: There was no significant difference in subclinical infection between those with positive and negative IFAT before vaccination, with different cut-off values for identifying subclinical infection. In both vaccinated and control groups with negative IFA before vaccination, subclinical infection rate was 7.62% in the controls, and 2.17% and 1.63% in the vaccinated ones, with cut-off values of 1:160 and 1:320, respectively, significantly different from that in the former. Subclinical infection rate was 11.38% and 6.78% in the vaccinated ones, as cut-off values of 1:20 and 1:40, respectively, without significant difference from the controls. CONCLUSION: No increase in subclinical infection in the vaccinated group with type I inactivated vaccine against HFRS was found.

Adolescent↗

PubMed1999

[A study on immunogenicity and safety of bivalent inactivated vaccine against hemorrhagic fever with renal syndrome].

OBJECTIVE: To study side effects and effectiveness of bivalent inactivated vaccine against hemorrhagic fever with renal syndrome in population of a randomized controlled field trial. METHODS: Serum indirect immunofluorescent antibody in 167 persons and neutralization antibody (types I and II) in 69 persons, who received three-dose vaccine, were determined two weeks after immunization, and side effects in 657 vaccinees were observed within 72 houses after immunization. RESULTS: Serum positive conversion rate of indirect immunofluorescent antibody was 99.04% (166/167) with GMT of 24.51 +/- 2.06. Serum positive conversion rate of neutralization antibody was 100% (69/69), 91.30% (63/69) for types I and 88.41% (61/69) for type II, respectively. GMTs for type I and II neutralization antibody were 18.27 +/- 2.21 and 12.47 +/- 2.16, respectively. Side effects at local site vaccinated of the body and temperature rising could be seen in 1.48% and 0.36% of the vaccinees, respectively. No severe side effect and abnormal reaction was found in vaccinees on the field. CONCLUSION: Immune response to bivalent inactivated vaccine against hemorrhagic fever with renal syndrome was satisfactory with slight side effect.

Adolescent↗

PubMed1999

[Studies on reduction of Au3+ by bacteria for preparing gold catalyst].

The strain D01, screened from different source bacterial strains, has relatively strong ability of adsorbing Au3+. The strain D01 was identified as Bacillus megatherium D01 and still grew well in the medium containing 600 mg/L Au3+. The results of electrochemical reaction indicated that the strain D01 had a strong ability of reduction. It could reduce the Au3+/alpha-Fe2O3(precursor of the gold catalyst) to highly dispersive Au0/alpha-Fe2O3 catalyst which could catalyze the reaction of CO + O2-->CO2.

Adsorption↗

PubMed1999

[FTIR and FT-Raman studies on interactions between water and surfactants in water/KDEHP (75%)-HDEHP (25%)/n-HEPTANE microemulsion systems].

The conformation of the hydrocarbon chains in water/KDEHP(75%)-HDEHP(25%)/n-HEPTANE microemulsion systems was studied by FT-Raman spectroscopy. The increase in the intensity ratio Ir (I2937/I2875) showed trans to gauche transformation. The hydration of the polar heads in microemulsions was investigated by FT-IR spectroscopy. Some probable structures of KDEHP and HDEHP in microemulsions were proposed.

Emulsions↗

PubMed1999

[Water structure in water/KDEHP-HDEHP/n-Heptane microemulsion by FTIR spectroscopy].

The structure of water in microemulsion is one of the basic subjects in the field of surface science. FTIR spectroscopy is considered as a powerful tool in the study on water structure. In this paper, we investigated water structure in the water/KDEHP (potassium bis (2-ethylhexyl) phosphate) -HDEHP/n-Heptane system. By using the Fourier self-deconvolution and curve-fitting method, the OH stretching band of water in the KDEHP-HDEHP microemulsion was resolved into four subpeaks which were tentatively assigned to absorbances of four different components of water. In order to explain the variations of peak positions of subpeaks with water content some probable hydration models of surfactants were proposed.

English Abstract↗