ABSTRACT
Objective To develop a new type of Raman-enhanced substrate for rapid detection of E.coli based on label-free surface-enhanced Raman scattering( SERS) technology.Methods Stober’ s improved method was used to prepare 360 nm silica ( SiO2 ) nanospheres.Prepared gold core-silver shell nanoparticles( Au@Ag) of different size were attached to 360 nm SiO2 to fabricate the nanocomposites ( SiO2-Au@Ag ) that were characterized by transmission electron microscopy (TEM) and UV-visucl light adsorption spectra (UV-Vis).PATP was detected to select SiO2-Au@Ag with optimal SERS effect.This optimal SiO2-Au@Ag was used to obtain the sensitivity of PATP and E.coli detection after a simple mixed culti-vation.Results TEM images showed that Au@Ag aggregated with the size of Au@Ag attached to 360 nm SiO2 .UV-Vis spectra indicated that the maximum absorption of Au@Ag and SiO2-Au@Ag had a red shift with the invrease of Au@Ag size.The experiment results suggested that detection sensitivity of PATP by SiO2-100 nm Au@Ag 10 -10 mol/L, while the lowest detectable E.coli concentration was 105 CFU/ml.Conclusion The 360 nm SiO2 binding with 100nm Au@Ag exhibits great potential for SERS applications.
ABSTRACT
As a weapon of mass destruction ,the biological weapon , composed of biological warfare agents and their re-lease devices,is characterized by strong pathogenicity , large pollution areas, various routes of infection, low cost, user-friendliness and a large number of impact factors .Although the United Nations has banned the use of biological weapons , there are still some countries and regions that continue biological weapon researches .In addition, illegal use of biological warfare agents in the field of terrorism and non-military arena poses a serious threat to public safety .Early detection of bio-logical warfare agent use and determination of its type are crucial to biological weapon defense and epidemic control .There-fore, to enhance researches on rapid detection and early warning of biological warfare agents is of great significance .This paper reviews the main technologies currently applied to the field of biological warfare agent detection and their progress .
ABSTRACT
The effect of riboflavin deficiency on the fluidity of erythrocyte (RBC) membrane, the level of membrane MDA, the activity of RBC SOD and lipid peroxidation were studied. Growing male rats were fed with an experimental (riboflavin-deficient, RD) or a control (riboflavin-supplemented, RS, 22mg/ kg) diet for 7 weeks.The RBC membrane of RD rats contained higher level of MDA (0.6868?0.1732 nmol/mg protein) compared with the control (0.5548?0.0980 nmol/mg protein), while the activity of RBC SOD (7.745210.6101 nU/mg protein) of RD rats were significantly decreared compared with the control (8.2685?0.3010 nU/mg protein), which indicated the lipid peroxidation was elevated.Membrane fluidity was studied with fluorescence polarization (P) and mean microviscosity (?) using DPH as probe. The value of P and? of RD rats (0.2976 ? 0.0198, 3.9483? 0.3680, respectively) were significantly higher than the RS rats (0.2760 ? 0.0207, 2.875310.4634, respectively), which showed the membrane fluidity in RD rats was decreased according with the increase in lipid peroxidation. This study demonstrated that the RBC membrane fluidity was dicrcased in riboflovin deficient rats. It was relative to the increasing lipid peroxidation and decreasing RBC SOD activity.
ABSTRACT
This paper was designed to study the effects of cellulose, pectin and ag-ar at 10% level on the concentration of serum total cholesterol (TC), trigly-ceride (TG) and high density lipoprotein cholesterol (HDL-C) in rats. Male adult Wistar rats were randomly divided into 5 groups and fed on basal diet, hypercholesterolemic diet (control diet) and 3 test diets (contain 10% cellulose, pectin or agar respectively) for 6 weeks. The results showed that all three fibrous diets were significantly lowered serum TC (P
ABSTRACT
The 5 foods, apple, bran, cabbage, carrot and pear, were fed to rats as part of 5 diets each containing 2.5% neutral detergent fiber (NDF) and the effect on increasing dry stool weight (DSW) and the digestibility of dietary fiber (DF) components of the foods were studied. The results showed that DSW increased with increased NDF intake, cabbage being the most effective. The mean DSW of the test food groups was 2.27 times compared with non-fiberous controls. The SDW was correlated with intake of NDF and cellulose from analysis of individual variation. The regression equation was y =- 1.9040 + 3.5644X1 (NDF) + 3.5644X2 (cellulose).The digestion of DF components from carrot was the most complete, while hemice-llulose was 1.3 times as digestible as cellulose. Lignin was found to have an influence on DF breakdown. Increasing hemicellulose level might decrease the digestibility of cellulose. The variation of DF digestibility of di- fferent food may also be ascribed to the physical and biological properties of the food.