EXRERIMENTAL STUDY OF THE PULSED WATER-GAS JET

A new pulsed jet device is presented which can produce oscillatory pulsed wafergas jet. This device is used in the erasive experiment on the while sandbrick whose compressive resistance is 30 Mpa. The curves of the erasive effects of the oscillatory pulsed water-gas jet.the oscillatory pulsed jet and the ordinary jet are drawn in order to be compared.which are changed as the distances of the targets are changed. In addition the reason why the erasive effect of the new jet is superior to the other two jets is analyzed.     

On the Noise Analysing and Reducing for Refrigeratory compressors

This paper propose an approach to reduce the regular pulse noise from ofQD55A air flow refrigerator compressor.The Rource is analysed by spectral a nalyeis techiques.Thenoise level is droped 4dB via massive preduction testing verification,and a desirable result on noise reduction has been obtained.     

Study on Hydrokinetics of the Unsubmerged Premixed Abrasive Water Jet

A mono-liquid model is established according to formative character of the premixed abrasive water jet. The hydraulic structure is analyzed by the model. The relationship that is obtained between the axial shaft line velocity and the forget distance by the law of conservation of momentum is verified with the experiment.     

Molluscicidal saponins from Sapindus mukorossi,inhibitory agents of golden apple snails,Pomacea canaliculata

Extracts of soapnut, Sapindus mukorossi Gaertn. (Sapindaceae) showed molluscicidal effects against the golden apple snail, Pomacea canaliculata Lamarck. (Ampullariidae) with LC(50) values of 85, 22, and 17 ppm after treating 24, 48, and 72 h, respectively. Bioassay-directed fractionation of S. mukorossi resulted in the isolation of one new hederagenin-based acetylated saponin, hederagenin 3-O-(2,4-O-di-acetyl-alpha-l-arabinopyranoside)-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (1), along with six known hederagenin saponins, hederagenin 3-O-(3,4-O-di-acetyl-alpha-l-arabinopyranoside)-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (2), hederagenin 3-O-(3-O-acetyl-beta-d-xylopyranosyl)-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (3), hederagenin 3-O-(4-O-acetyl-beta-d-xylopyranosyl)-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (4), hederagenin 3-O-(3,4-O-di-acetyl-beta-d-xylopyranosyl)-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (5), hederagenin 3-O-beta-d-xylopyranosyl-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (6), and hederagenin 3-O-alpha-l-arabinopyranoside (7). The bioassay data revealed that 1-7 were molluscicidal, causing 70-100% mortality at 10 ppm against the golden apple snail.     

Influence of Maillard reaction products on DNA damage in human lymphocytes

The effect of Maillard reaction products (MRPs) on induced DNA damage in human lymphocytes was investigated using single-cell gel electrophoresis (comet assay). Three MRPs, Xyl-Lys MRP, Glu-Lys MRP, and Fru-Lys MRP, were prepared by heating lysine with xylose, glucose, and fructose, respectively, at pH 9.0 and 100 degrees C for 3 h and called undialyzed MRPs. The prepared MRPs were further dialyzed, and three undialyzable MRPs were obtained. The undialyzed MRPs caused significant (p < 0.05) DNA damage in human lymphocytes at a concentration of 0.05-0.1 mg/mL by the comet assay. Compared with the control, the undialyzable Xyl-Lys MRP and Glu-Lys MRP caused significant DNA damage in human lymphocytes at a concentration >0.1 mg/mL, whereas Fru-Lys MRP did so at a concentration >0.2 mg/mL. Moreover, undialyzed MRPs caused less DNA damage than did undialyzable MRPs. The undialyzable MRPs did not affect the activity of glutathione peroxidase or lipid peroxidation in human lymphocytes at a concentration of 0.05-0.8 mg/mL. However, these three undialyzable MRPs decreased the glutathione (GSH) contents and the activities of GSH reductase and catalase in human lymphocytes. On the basis of the results of the formation of 8-hydroxy-2'-deoxyguanosine, radicals, and hydrogen peroxide, the radicals might play an important role in the DNA damage in human lymphocytes induced by these MRPs in this reaction system.     

Addition of sugars influences color of oil-in-water emulsions

The influence of glucose, fructose, lactose, and glycerol on the color and appearance of surfactant-stabilized oil-in-water emulsions containing a red dye was investigated. A stabilized (Tween-20) oil-in-water emulsion was diluted into sugar solutions to give a range of oil droplet and sugar concentrations. Tristimulus coordinates (L, a, b) and reflectance spectra were measured using a spectrophotometer. With increasing sugar concentration, reflectance spectra shifted to lower reflectance values. Tristimulus coordinates were reduced by approximately 50% for emulsions containing high concentrations of sugar. Adding fructose to emulsions reduced L, a, b values more significantly than adding glucose, lactose, or glycerol. Tristimulus coordinates remained constant when the temperature was raised from 20 to 80 degrees C. The experimental results were explained in terms of the change of relative refractive index at the water-oil interface. The results have important implications for the food industry as they offer a new means to control and optimize the color of food emulsions.     

Simultaneous residue measurement of pendimethalin, isopropalin, and butralin in tobacco using high-performance liquid chromatography with ultraviolet detection and electrospray ionization/mass spectrometric identification

A simultaneous residue analysis of pendimethalin, isopropalin, and butralin in tobacco was developed with high-performance liquid chromatography with ultraviolet monitoring and electrospray ionization mass spectrometry (HPLC-UV-ESI/MS). The herbicide residues of pendimethalin, isopropalin, and butralin in tobaccos were extracted by ultrasonication with ethyl acetate, followed by a cleanup procedure with gel permeation chromatography. The three herbicides were separated within 15 min using a LiChrosorb 18 column with methanol-10 mmol/L ammonium acetate (85:15, v/v) as the eluent. The limits of quantitation, using HPLC-UV, were ca. 0.05, 0.08, and 0.06 mg/kg for pendimethalin, isopropalin, and butralin, respectively, whereas the overall recoveries ranged from 77.5 to 91.8%. The proposed method has been successfully applied to measure 300 real samples, and the residue profiles of three herbicides in tobacco samples were obtained and evaluated.     

Phenylpropanoid glycosides and triterpenoid of Pedicularis kansuensis Maxim

Phytochemical investigation of the ethanol extract of Pedicularis kansuensis Maxim. led to the isolation of one new triterpenoid and two new phenylpropanoid glycosides, along with ten known compounds. Their structures were established by extensive 1D and 2D NMR, as well as other spectrum analysis. Biological evaluation of the three new compounds against Hela cell and Hep-6 cell with MIC values ranging from 9 to 20 μg/ml.     

低植酸与高植酸含量日粮中植酸酶的添加量对于生长猪在粗蛋白、氨基酸及能量消化力上的影响

添加微生物植酸酶通常可以提高植物性饲料中磷的消化率和利用率。对于植酸酶的添加是否影响氨基酸的消化同样作了测定,但结果不一致。本研究测定植酸酶(Natuphos)的添加量(每千克日粮添加2000单位的植酸酶,设计两种基础日粮)对于GE、CP和AA回肠表观消化率(AID)以及CP和GE全消化道表观消化率(ATTD)的影响。两种基础日粮含CP18%,一种含较低量(0.22%)的植酸磷,另一种含较高量(0.48%)的植酸磷。高植酸含量的日粮含有20%的米糠,富含植酸而本身植酸酶活性较低。试验按照4×4拉丁方设计,对初始平均重为40.6 kg的8头阉猪回肠末端安装简易T型套管并饲喂4种日粮。饲喂2次/d,时间分别在8:00和20:00,每次的量相同,ME是维持需要量的2.4倍。每组试验期为14 d。第12、13及14 d收集回肠消化物,时间为8:00到20:00。粪便的收集是从第8 d的8:00到第12d的8:00。Cr2O3作为消化率测定的标记物。结果表明:高植酸含量日粮的GE、CP和AA回肠表观消化率(AID)以及CP和GE全消化道表观消化率(ATTD)低于低植酸含量的日粮(P<0.01);除谷氨酸外,植酸酶的添加量不会影响CP和AA的回肠表观消化率(P>0.10);植酸酶的添加量不影响CP和GE的全消化道表观消化率(P>0.05)。这些结果提示添加植酸酶的效果和日粮植酸含量无关。