碳酸奶生产工艺评价

在乳酸菌发酵和直接加乳酸调配2种工艺的基础上,研制了一种较好的酸奶生产工艺.试验表明这种工艺生产的碳酸奶风味好,组织细腻润滑,强化贮存1个月后各项指标均稳定.     

Does DDT inhibit carbonic anhydrase?

At a concentration of 50 to 100 micrograms per milliliter, p,p'-DDT (and p,p'-DDE) did not inhibit the rate of hydration or dehydration of carbon dioxide by carbonic anhydrase. At concentrations greater than 500 micrograms per milliliter, partial inhibition of the rate of dehydration of carbonic acid was observed, but this involved precipitation of drug in the reaction vessel. This degree of inhibition suggests that DDT may not inhibit carbonic anhydrase effectively at the usual concentrations found in tissue after exposure of organisms to DDT in the environment.     

蛋壳中碳酸钙转化为柠檬酸钙的研究

【目的】通过酸性介于碳酸和柠檬酸之间的有机酸与蛋壳反应制得有机酸钙,再与柠檬酸反应,置换出柠檬酸钙。【方法】试验对有机酸进行筛选,选定有机酸为乙酸。对试验过程中的各个影响因子进行研究,得到最佳工艺条件。采用三元二次回归正交旋转组合设计对试验进行优化,然后对产品进行纯化处理。【结果】优化后的最佳工艺条件为蛋壳过量30%、固液比1∶19.8、蛋壳粉与乙酸在25.4℃下反应3.5 h、柠檬酸与乙酸钙在50℃下反应3 h、加入柠檬酸的不足量为25.4%。【结论】在优化后的最佳工艺条件下利用蛋壳制备柠檬酸钙的产率为86.2%,纯化后的最终产率为85.4%,纯度达99%以上。     

Deep-Sea pH

In the northeastern Pacific Ocean, north of 22 degrees N and east of 180 degrees W, a deep-sea pH maximum of 7.9 exists near 4000 meters. The effect of hydrostatic pressure on the dissociation constants of carbonic acid in sea water appears to be important in its formation.     

大豆子叶中的碳酸酐酶活性和光合特性研究

水培大豆幼苗,研究大豆子叶生理过程中,其叶绿素a,b和类胡萝卜素含量,光合速率以及碳酸酐酶活性,进一步认识子叶在幼苗初期生长中的作用。试验结果表明,在大豆子叶中有大量的光合色素合成,大豆子叶能够进行光合作用,并能够测出子叶中碳酸酐酶活性,并且子叶净光合速率、碳酸酐酶活性大小与光合色素含量显著相关。大豆子叶中光合色素含量、碳酸酐酶活性和光合能力随着子叶的生理作用变化而变化,开始随着子叶的发育而增加,第7天达到最大值,然后随着子叶的凋零而不断下降。     

盐胁迫下小黑麦碳酸酐酶基因表达及其酶活性分析

[目的]探究盐胁迫下小黑麦中碳酸酐酶(CA)基因表达特点及酶活性变化规律.[方法]采用0.15M NaCI对两个六倍体小黑麦品种幼苗进行胁迫处理,通过实时荧光定量PCR对胁迫条件下CA基因表达量的变化进行检测,并利用pH计法对相应材料中的碳酸酐酶活性进行测定.[结果]盐胁迫条件下两个小黑麦品种幼苗中的CA基因表达量及酶活性均较对照有所增强.随胁迫时间的不同,参试的两个小黑麦品种中CA基因表达量及酶活性变化的幅度有一定差异.[结论]盐胁迫对小黑麦中CA基因的表达量和酶活性均具有促进作用.     

Forest floor leaching: contributions from mineral, organic, and carbonic acids in new hampshire subalpine forests

Analyses of soil water and groundwater samples from a high-elevation coniferous ecosystem in New England indicate that sulfate anions supply 76 percent of the electrical charge balance in the leaching solution. This result implies that atmospheric inputs of sulfuric acid provide the dominant source of both H(+) for cation replacement and mobile anions for cation transport in subalpine soils of the northeastern region affected by acid precipitation. In soils of relatively unpolluted regions, carbonic and organic acids dominate the leaching processes.     

Plasma 3S gamma-1-globulin: identity with erythrocyte carbonic anhydrase B

The 3S (gamma1), 2S (gamma2), and 0.5S (gamma2) fractions of human plasma are heterogeneous in protein composition. Although each fraction contained a relatively small amount of protein antigenically related to the immunoglobulin light chains, most of the proteins were unrelated to immunogloublin G or its light chains. Of the 3S (gamma1)-globulins the greater part was immunochemically identical to carbonic anhydrase B and had carbonic anhydrase activity. These findings explain earlier reports of an immunochemical similarity between 3S (gamma1)-globulins and immunoglobulin light chains in spite of marked differences in amino acid and peptide composition between the two. Apparently not all plasma gamma-globulins are necessarily immunoglobulins.     

生长调节物质对油菜碳酸酐酶活性的影响

利用植物生长调节物质处理油菜幼苗,结果表明不同生长调节物质以及不同浓度下的油菜碳酸酐酶活性不同,其中,6-BA与GA的适宜浓度为5.00μmol/L,而NAA的浓度为0.50μmol/L,各处理下油菜碳酸酐酶活性都有一个先上升后下降的过程,说明极低浓度的生长调节物质都会对油菜碳酸酐酶活性与生长产生明显的效果。     

竹材表面润湿性能研究

以毛竹为研究对象,通过表面改性措施,增加毛竹界面的润湿性,达到直接胶接热压的目的。改性方法主要有酸处理、碱处理和等离子体处理,3种方法通过不同试验水平处理后,通过接触角的测定表征竹材界面润湿性的处理效果。酸处理对表面的接触角影响较大,竹青最大降幅为53.6%,竹黄为23.0%。碱处理后,竹青最大降幅为48.4%,竹黄为18.5%,略次于酸,效果明显。等离子体用较短的时间处理,竹青接触角即可显著降低,界面润湿性有很大提高,但竹黄面处理前后接触角的差异较小。综合得出,HCl处理效果最佳,NaOH处理次之,相对酸碱处理,等离子体处理效果较弱。3种处理方法均是竹青接触角的降幅很明显,竹黄次之。     

碳钢二氧化碳腐蚀研究现状

二氧化碳腐蚀是油气中的二氧化碳（ＣＯ２）溶解于水后生成碳酸后引起的腐蚀。综述了在二氧化碳环境中,碳钢金属表面有产物膜和无产物膜存在的情况下腐蚀机理。分析了温度、二氧化碳分压、流速、ｐＨ值及腐蚀产物膜对二氧化碳腐蚀的影响。认为碳钢的二氧化碳腐蚀机理因金属是否形成碳酸铁（ＦｅＣＯ３）膜而不同,二氧化碳分压和洗速影响着腐蚀的阴极过程,而温度主要是影响腐蚀产物膜的形成条件。在局部腐蚀领域内开展基础性和应用     

Vertical distribution of water in the atmosphere of venus: a simple thermochemical explanation

Several lines of evidence concerning the vertical abundance profile of water in the atmosphere of Venus lead to strikingly unusual distributions (the water vapor abundance decreases sharply in the immediately vicinity of the surface) or to serious conflicts in the profiles (different infrared bands suggest water abundances that are discrepant by a factor of 2.5 to 10). These data sets can be reconciled if (i) water molecules associate with carbon dioxide and sulfur trioxide to make gaseous carbonic acid and sulfuric acid in the lower atmosphere, and (ii) the discrepant 0.94-micrometer water measurements are due to gaseous sulfuric acid, requiring it to be a somewhat stronger absorber than water vapor inthis wavelength region. A mean total water abundance of 50 +/- 20 parts per million and a near-surface free water vapor abundance of 10 +/- 4 parts per million are derived.     

Carbonic anhydrase and osteoclasts: localization by labeled inhibitor autoradiography

Autoradiography with tritiated acetazolamide indicates that osteoclasts of the hen and chick contain concentrations of carbonic anhydrase which are similar to those in pancreatic acinar cells. Grain counts of osteoblasts and osteocytes were not different from background. Thus, a sufficient quantity of carbonic anhydrase seems to be present in osteoclasts to be of physiological importance in bone resorption.     

循环水结垢和腐蚀的机理及其控制

从理论上论述了循环水系统水垢的形成和水对循环系统的腐蚀机理，指出，当循环水系统普遍存在结垢时，由于水垢隔绝了金属与水的接触，腐蚀不会发生；而当水垢倾向于溶解时就会发生腐蚀，水垢的形成主要是由于循环水中含有碳酸钙。     

饱和CO2对亚心形扁藻生长及碳酸酐酶活性的影响

[目的]研究饱和CO_2对亚心形扁藻生长及细胞内、外碳酸酐酶活性的影响。[方法]在每个光周期的光照阶段开始时通入CO_2至饱和,在每个光周期的黑暗阶段结束时取样测定亚心形扁藻细胞的生物量、叶绿素含量及碳酸酐酶比活性。[结果]与未通入CO_2的对照组相比,通入CO_2至饱和时亚心形扁藻的适应期缩短,进入生长期后生物量增加明显,至培养结束时的生物量、叶绿素a和叶绿素b含量、细胞内外碳酸酐酶、总碳酸酐酶比活性分别是对照组的1.19、1.75、1.66、1.32、1.26、1.43倍。[结论]在培养体系中通入CO_2至饱和时,亚心形扁藻通过提高细胞内、外碳酸酐酶的活性来保持高光合作用效率,促进自身生长繁殖。     

构树与桑树叶片的碳酸酐酶胞外酶活力比较

[目的]为研究碳酸酐酶胞外酶在植物生理活动过程中的调节作用提供理论依据。[方法]以构树和桑树上部叶片为材料,采用pH锑微电极代替传统的pH玻璃电极测定其碳酸酐酶及碳酸酐酶胞外酶活力。[结果]构树的碳酸酐酶及碳酸酐酶胞外酶活力明显高于桑树,但2树种碳酸酐酶胞外酶活力占总酶活力的比例无显著差异。构树的碳酸酐酶胞外酶活力为1 500-3 000 WAU/g（FW）,占碳酸酐酶总酶活力的20%-40%;桑树的碳酸酐酶胞外酶活力为200-400 WAU/g（FW）,占碳酸酐酶总酶活力的25%-35%。[结论]该研究为探索构树和桑树对生理逆境的生态适应性机制提供了新的证据。     

埋地高温稠油集输管道内防腐研究

辽河油田稠油开发主要以热力采油为主，人为地使油井采出物中二氧化碳的含量增加。集输管道内的二氧化碳溶于水后生成稀碳酸溶液，形成了腐蚀环境，管道所输送的油井采出物中还含有氯化氢、硫化氢及氢气，在这样的腐蚀环境和腐蚀介质中。集输管道遭受严重的腐蚀破坏。通过现场调查和技术经济对比，提出采用管道内防腐挤涂施工工艺，使管道内壁形成保护层，可以完全控制腐蚀。     

光质对组培苗叶绿素含量和碳酸酐酶活性及生长的影响

以十字花科植物诸葛菜和油菜组培苗为试材,研究4种不同光质对组培苗叶绿素含量、碳酸酐酶活性和生长量的影响,结果表明：红蓝混合光能明显促进组培苗叶片叶绿素含量和碳酸酐酶活性,植株形态建成最佳,但是对生长量没有显著影响;认为红蓝混合光（灯）能提高组培苗的光合自养能力,适合作为组培室光源。     

从形态学特征和腐殖质组分谈内蒙古黑垆土的演化

黑垆土作为１个独立的土类,在内蒙古自治区南部温带地区分布有其特殊意义。该土类的形态学特征是具有深厚的暗褐色的腐殖质层,耕作层较黄土高原的黑垆土薄,无古老的耕作层;土体中有碳酸盐假菌丝状新生体、碳酸盐含量较低在１％上下。腐殖质含量较低在１％～３％,胡敏酸和富里酸比值在剖面中下部达到２以上,胡敏素相对含量较低,一般不超５０％。该区域分布的黑垆土是温带草甸草原黑钙土演变的结果。     

Identification of specific transducin alpha subunits in retinal rod and cone photoreceptors

Transducin is a guanyl nucleotide-binding protein that couples rhodopsin photolysis to hydrolysis of guanosine 3',5'-monophosphate in rod photoreceptor cells of vertebrate retinas. Several complementary DNA clones encoding transducin subunits have recently been characterized. One clone, isolated from a bovine retina complementary DNA library, encodes a previously unidentified polypeptide with an amino acid sequence 78% identical to the sequence of the alpha subunit of bovine rod outer segment transducin. Antibodies to a synthetic peptide with amino acid sequence derived specifically from this novel polypeptide recognize a 41-kilodalton polypeptide in homogenates of bovine retina. Localization of this polypeptide in bovine retina by indirect immunofluorescence demonstrates that it is expressed only in cone outer segments. Antibodies to specific sequences found only in the rod transducin alpha subunit recognize a polypeptide localized only in the rod outer segment. Therefore, bovine rod and cone cells each express structurally related yet significantly different forms of transducin.