Anticancer activity of bovine α‐lactalbumin treated with microbial transglutaminase

This study investigated the effects of bovine α‐lactalbumin (α‐La) treated with microbial transglutaminase on human cancer cells, cell cultures and growth rate assays. The anticancer activity for 10 mg/mL of bovine α‐lactalbumin (α‐La) was measured as ～90% in a human colorectal cancer cell line HCT 116. For the human bone cancer cell line SJSA‐1, α‐La hydrolysis resulted in higher cytotoxicity compared to untreated tumour cells. The formation of polymers of α‐La was suppressed by the addition of ethylenediaminetetraacetic acid, indicating that polymers of α‐La are promoted by metal ions such as Ca²⁺. The effect of α‐La on the morphology of SJSA‐1 cells was manifested as morphological changes compatible with apoptosis. Bovine milk α‐La with and without microbial transglutaminase is considered a valuable food ingredient and a nutraceutical for human health.     

PURIFICATION AND CHARACTERIZATION OF PROTEASES FROM HEPATOPANCREAS OF CRAWFISH (PROCAMBARVS CLARKII)1

Four trypsin‐like enzymes (CP‐I, II, III and IV in order of elution on DEAE‐Sepharose chromatography), purified from the hepatopancreas of crawfish, were inhibited by protease inhibitors such as phenyl methyl suifonyl fluoride (PMSF), soybean trypsin inhibitor (SBTI), aprotinin and tosyl lysine chloromethyl ketone (TICK). The molecular weights of CP‐I, II, III and IV were determined to be 35.0, 41.2, 37.9 and 39.5 kDa, respectively, using sodium dodecyl sulfate polyacryl‐amide gel electrophoresis (SDS‐PAGE), These proteases had optimal esterase activity at pH 8.0–8.5 and showed the highest activity at 60–70C. Crawfish proteases were rich in acidic amino acids. Activation energies for hydrolysis of tosyl arginine methyl ester (TAME) by these proteases were 6.98 – 8.34 kcal/mole. Unlike other serine proteases, the activities of CP‐I and CP‐II were activated by mercury while CP‐HI and IV were inhibited.     

Electrochemical behavior of dental implant system before and after clinical use

Electrochemical behavior of dental implant system before and after clinical use (in vivo and in vitro) was researched by using abutment and titanium fixture. To simulate an oral environment, the samples of clinically used and non-used implant systems as a working electrode were exposed to artificial saliva at (36.5±1) °C. Electrochemical tests were carried out using a potentiostat. After electrochemical test, the corrosion morphology of each sample was investigated by FE-SEM and EDS. The corrosion potential and pitting potential of clinically used implant system are lower than those of non-used implant system, and clinically used implant system exhibits a lower range of passivation, indicating a less degree of inherent resistance against chloride ion. The polarization resistance decreases in the case of clinically used implant system, whereas, R_p for clinically non-used implant system increases compared with clinically used implant system.     

Water sorption characteristics of dried red peppers (Capsicum annum L.)

The water sorption isotherms of whole dried red pepper pods at 15, 25, 40°C were measured, and the results were used to test the applicability of the GAB equation, BET equation, and modified BET equation. the GAB, BET, and modified BET equations fitted the data well for water activities up to 0.93, 0.43, and 0.75, respectively. the monolayer values were found to range between 6 and 10 g H₂O per 100g solid, depending on temperature and the equation used for estimation. the excess heat of sorption as a function of moisture content was also determined.     

Diurnal Variations of Summer Precipitation in the Beijing Area and the Possible Effect of Topography and Urbanization

The present study examined the diurnal variations of summer precipitation in the Beijing area by using subdaily precipitation and wind observations.A combined effect of topography and urbanization on the characteristics of diurnal variations was suggested.It was shown that stations located in the plain area exhibited typical night rain peaks,whereas those in the mountainous area exhibited clear afternoon peaks of precipitation diurnal variations.The precipitation peaks were associated with wind fields around the Beijing area,which were found to be highly modulated by mountain-valley circulation and urban-country circulation.The lower-tropospheric wind exhibited a clear diurnal shift in its direction from north at 0800 LST to south at 2000 LST,which reflected mountain-valley circulation.The transitions from valley to mountain wind and the opposite generally happened after sunset and sunrise,respectively,and both occurred earlier for the stations located closer to mountains.By comparing the diurnal variations of precipitation at stations in a northeast suburb,an urban area,and a southwest suburb,it was revealed that the northeast suburb group had the highest normalized rainfall frequency,but the southwest group had the lowest from late afternoon to late evening.On the contrary,in the early morning from about 0200 to 1000 LST,the southwest group and urban group had the highest normalized rainfall frequency.This pattern might originate from the combined effects of mountain-valley topography and urbanization.     

EFFECT of PLASTICIZER LEVEL and TEMPERATURE ON WATER VAPOR TRANSMISSION of CELLULOSE-BASED EDIBLE FILMS1

This study was conducted to determine water sorption isotherms of cellulose-based films made from methyl cellulose (MC) and hydroxypropyl cellulose (HPC), and to evaluate the effect of plasticizer concentration and temperature on water vapor permeability coefficient in those films. the equilibrium moisture contents of MC film and HPC film increased slowly with an increase in water activity (a_w) up to 0.75, but increased greatly after 0.75 a_w. the water vapor permeability coefficient of HPC film increased as the concentration of polyethylene glycol (PEG) increased; however, the water vapor permeability coefficient of MC film which contained 0.22 ml PEG/g cellulose was lower than of films which contained no or higher PEG. an Arrhenius-type relationship was fitted to examine temperature dependence of water vapor permeability coefficients of cellulose films. the edible films studied exhibited relatively low activation energies (14.56–16.43 kJ/mol) compared with typical food packaging materials.     

生物植入用碳纳米管增强混合功能梯度材料的力学性能(英文)

利用羟基磷灰石(HA)、不锈钢316L(SS316L)和碳纳米管(CNT)制备生物医学植入体用混合功能梯度材料(FGM)。加入SS316L和CNT增强功能梯度材料离散层的HA制成三种不同类型的功能梯度材料。第一种功能梯度材料加入10%~40%(质量分数)的SS316L强化微米HA,浓度梯度为10%。第二种功能梯度材料,在第一种功能梯度材料的基础上加入0.5%(质量分数)的功能化碳纳米管。第三种功能梯度材料在第二种功能梯度材料的基础上加入微米HA和纳米HA(1:1)的混合物。所有类型的功能梯度材料在相似的压缩参数和烧结参数下,进行单轴压缩实验,并采用无压烧结技术进行烧结。结果表明,加入碳纳米管和纳米晶体HA提高了功能梯度材料的致密度。碳纳米管增强的功能梯度材料的硬度和断裂韧性增加,但是微米和纳米晶体HA增强的功能梯度材料的硬度和断裂韧性的增加更明显。     

玻璃制作工具用5%ZrO_2纳米铂材的机械合金化制备(英文)

对机械合金化制备的玻璃工业中用作结构零件的Pt-5%ZrO2(体积分数)的进行表征。通过锆丝电爆炸法制备氧化锆(ZrO2)纳米颗粒(粒径100 nm),并在室温下与铂粉(粒径44?m)球磨2~72 h。普通球磨至48 h时,铂粒径遵循经典的递减趋势,至72 h时观测到颗粒团聚现象。晶粒尺寸演变规律与颗粒尺寸规律相似,48 h后减至50 nm左右。但是,铂晶粒的均方根应变规律相反,一直在增长,直至48 h时得到最大值,然后出现弛豫。粉末球磨48 h后,采用放电等离子体烧结制成块体。根据测量得到烧结体的质量损失表明:合金虽然相对密度较低,但有较好的热稳定性。     

AN ANALYTICAL SOLUTION FOR A TUBULAR REACTOR MODEL WITH DISPERSION IN BOTH RADIAL AND AXIAL DIRECTIONS

An analytical solution for an unsteady-state tubular reactor model with dispersion in the radial as well as in the axial direction is presented. An arbitrary initial concentration profile and an arbitrary time-varying feed concentration are allowed; and the reaction occurs also on the interior surface wall of the reactor. The problem is recast into a more tractable form by an exponential transformation and then the method of Green's function combined with the orthonormal eigenfunction expansions based on the solution of the associated Helmholtz equation is used to arrive at the solution.     

玻璃制作工具用5%ZrO2纳米铂材的机械合金化制备（英文）

对机械合金化制备的玻璃工业中用作结构零件的Pt-5%ZrO2(体积分数)的进行表征。通过锆丝电爆炸法制备氧化锆(ZrO2)纳米颗粒(粒径<100 nm),并在室温下与铂粉(粒径<44?m)球磨2~72 h。普通球磨至48 h时,铂粒径遵循经典的递减趋势,至72 h时观测到颗粒团聚现象。晶粒尺寸演变规律与颗粒尺寸规律相似,48 h后减至50 nm左右。但是,铂晶粒的均方根应变规律相反,一直在增长,直至48 h时得到最大值,然后出现弛豫。粉末球磨48 h后,采用放电等离子体烧结制成块体。根据测量得到烧结体的质量损失表明:合金虽然相对密度较低,但有较好的热稳定性。