共查询到20条相似文献，搜索用时 421 毫秒
1.
介绍了适用于环上椭圆曲线的加法公式,完善了局部环Z/pnZ上椭圆曲线密码学的基础理论,构造了环Z/pnZ上的基于角色的椭圆曲线密码系统.根据环Z/pnZ的结构特点,简化了其上椭圆曲线的加法完备系统,从而大大提高了环Z/pnZ上的椭圆曲线计算点加的效率;另外,给出了E(Z/pnZ)上密码群生成元的选取方法;证明Z/pnZ上的密码体系与有限域Fp的椭圆曲线密码体系有相同的安全程度;最后在环Z/pnZ上给出一个基于角色的椭圆曲线密码方案. 相似文献
2.
When the genus Yinshania Ma et Y. Z. Zhao was published, it had
only a single species, Y. albiflora Ma et Y. Z. Zhao which was indicated as the
type of the genus (Acta Phytotax. Sin. 1979). Y. Z. Zhao 155. was indicated as
the type specimen of Y. albiflora. It is adequate to cite Y. albiflora Ma et Y. Z.
Zhao as the type of genus Yinshania Ma et Y. Z. Zhao. In a revision (Acta Phyto-
tax. Sin. 25(3): 204-219, 1987) Y. H. Zhang made a combintion, Yinshania
acutangula (O. E. Schulz) Y. H. Zhang (=Cochlearia acutangula O. E. Schulz)
and reduced Yinshania albiflora Ma et Y. Z. Zhao as a variety of Y. acutangula,i.
e. Y. acutangula var. albiflora (Ma et Y. Z. Zhao) Y. H. Zhang. She is uncorrect,
however, when she cited Y. acutangula (O. E. Schulz) Y. H . Zhang as the type
of the genus Yinshania Ma et Y. Z. Zhao. It should be cited as follows:
Yinshania Ma et Y. Z. Zhao
Typus generis: Yinshania albiflora Ma et Y. Z. Zhao (=Yinshania acutangula(O. E. Schulz) Y. H. Zhang var. albiflora (Ma et Y. Z. Zhao) Y. H. Zhang) 相似文献
3.
Cara Young Kester Rozario Christophe Serra Laura Poole-Warren Penny Martens 《Biomicrofluidics》2013,7(4)
Biosynthetic microspheres have the potential to address some of the limitations in cell microencapsulation; however, the generation of biosynthetic hydrogel microspheres has not been investigated or applied to cell encapsulation. Droplet microfluidics has the potential to produce more uniform microspheres under conditions compatible with cell encapsulation. Therefore, the aim of this study was to understand the effect of process parameters on biosynthetic microsphere formation, size, and morphology with a co-flow microfluidic method. Poly(vinyl alcohol) (PVA), a synthetic hydrogel and heparin, a glycosaminoglycan were chosen as the hydrogels for this study. A capillary-based microfluidic droplet generation device was used, and by varying the flow rates of both the polymer and oil phases, the viscosity of the continuous oil phase, and the interfacial surface tension, monodisperse spheres were produced from ∼200 to 800 μm. The size and morphology were unaffected by the addition of heparin. The modulus of spheres was 397 and 335 kPa for PVA and PVA/heparin, respectively, and this was not different from the bulk gel modulus (312 and 365 for PVA and PVA/heparin, respectively). Mammalian cells encapsulated in the spheres had over 90% viability after 24 h in both PVA and PVA/heparin microspheres. After 28 days, viability was still over 90% for PVA-heparin spheres and was significantly higher than in PVA only spheres. The use of biosynthetic hydrogels with microfluidic and UV polymerisation methods offers an improved approach to long-term cell encapsulation. 相似文献
4.
关于密度函数公式的注记 总被引：11，自引：1，他引：11
给出了Z=X^2/a^2＋Y^2/b^2,Z=X^2/a^2-Y^2/b^2,Z=√X^2/a^2＋Y^2/b^2,Z=Y/aX^2的密度函数公式. 相似文献
5.
Sajitha GR Jose R Andrews A Ajantha KG Augustine P Augusti KT 《Indian journal of clinical biochemistry : IJCB》2010,25(3):280-288
Daily feeding of drinking water containing lead acetate (160 mg/l) or 10% alcohol by volume or a combination of both to rats
for a month produced certain deleterious effects through oxidative stress. Both heavy metal lead and alcohol are capable of
doing such damages. The deleterious alterations observed were in the parameters of blood, serum and tissues, viz; Hb, Pb,
proteins, lipids, lipid per oxidation, Vitamins C and E levels and enzyme activities of AST, ALT, and catalase. Simultaneous
feeding of either of the two antioxidants garlic oil (GO) and vitamin E at equal doses of 100 mg/kg/day, to the rats counteracted
the deleterious effects of the above two chemicals significantly. The maximum damage was brought about by feeding of drinking
water containing both lead acetate and alcohol. The protective effects of GO and Vitamin E were not significantly different.
The mechanism of actions of the Vitamin E and GO is probably due to their efficiency as detoxifying agents and antioxidants,
to scavenging free radicals as well as an independent action of GO on the removal of lead salt as lead sulfide. 相似文献
6.
BackgroundLarge amounts of β-alanine are required in fine chemical and pharmaceutical synthesis and other fields. Profitable and green methods are required for the industrial production of β-alanine.ResultsReplacing endogenous panD of Escherichia coli with heterologous CgpanD from Corynebacterium glutamicum enabled β-alanine synthesis of 0.67 g/L by strain B0016-082BB. Overexpressing CgpanD on both plasmids and chromosomes to enhance the rate-limiting step improved the β-alanine titer to 4.25 g/L in strain B0016-083BB/pPL451-panD with a slighter metabolic burden. Growth factors were introduced by addition of yeast extract, and 6.65 g/L of β-alanine was synthesized by strain B0016-083BB/pPL451-panD in the M9-3Y medium.ConclusionsEnhancement of the rate-limiting steps in the β-alanine biosynthetic pathway, recruitment of the temperature-sensitive inducible pL promoter, and optimization of the fermentation process could efficiently increase β-alanine production in E. coli.How to cite: Xua J, Zhua Y, Zhou Z. Systematic engineering of the rate-limiting step of β-alanine biosynthesis in Escherichia col. Electron J Biotechnol 2021;51. https://doi.org/10.1016/j.ejbt.2021.03.002. 相似文献
7.
8.
Optofluidics may hold the key to greater success of photocatalytic water treatment. This is evidenced by our findings in this paper that the planar microfluidic reactor can overcome the limitations of mass transfer and photon transfer in the previous photocatalytic reactors and improve the photoreaction efficiency by more than 100 times. The microreactor has a planar chamber (5 cm×1.8 cm×100 μm) enclosed by two TiO(2)-coated glass slides as the top cover and bottom substrate and a microstructured UV-cured NOA81 layer as the sealant and flow input∕output. In experiment, the microreactor achieves 30% degradation of 3 ml 3×10(-5)M methylene blue within 5 min and shows a reaction rate constant two orders higher than the bulk reactor. Under optimized conditions, a reaction rate of 8% s(-1) is achieved under solar irradiation. The average apparent quantum efficiency is found to be only 0.25%, but the effective apparent quantum efficiency reaches as high as 25%. Optofluidic reactors inherit the merits of microfluidics, such as large surface∕volume ratio, easy flow control, and rapid fabrication and offer a promising prospect for large-volume photocatalytic water treatment. 相似文献
9.
针对WRF模式自带土地利用数据更新不及时及精度不高的现象,本文将国内外主要土地利用数据（MODIS2012、GLC2009、GLC2000）与WRF模式耦合进行土地利用数据的优选,并将优选数据初步应用于枣庄城市热岛模拟中。结果表明：①MODIS2012数据能够较好地反映研究区域土地利用类型的空间分布特征,有较好的模拟结果;②研究区10月份热岛强度最大为0.671℃,其次是1月份和7月份分别为0.570℃和0.550℃,而4月份热岛强度较小为0.467℃;城市热岛强度日最大值出现在22~23点,最小值出现在13~14点;③由于盛行风向的影响,滕州市与枣庄市中区城市热岛中心均存在春夏季北进、秋冬季南移的现象;④枣庄地区城市热岛主要受枣庄市中区的影响,各土地利用类型对城市热岛的贡献率大小排序为：城镇建设用地>农田>林地>未利用地>草地>水体。 相似文献
10.
将Plantago erosa Wall. var. fengdouensis Z. E. Zhao & Y. Wang提升为一独立的种，即丰都车前P. fengdouensis (Z. E. Zhao & Y. Wang) Y. Wang & Z. Y. Li。该种由于花冠无毛，花丝着生于花冠近基部，子叶在种子中与腹面（种脐面）相平行，应属于车前亚属subgen. Plantago。丰都车前P. fengdouensis以植株干后变黑和种子较大的特征接近湿生车前P. cornuti Gouan，但其叶具牙齿或羽状锐裂，具3脉，苞片三角状卵形，花冠裂片狭三角形，蒴果纺锤状椭圆球形，近中部周裂，种子腹侧具1纵槽而不同于后者。 相似文献
11.
BackgroundZymomonas mobilis is a Gram-negative microaerophilic bacterium with excellent ethanol-producing capabilities. The RecET recombination system provides an efficient tool for direct targeting of genes in the bacterial chromosome by PCR fragments.ResultsThe plasmids pSUZM2a-RecET and pSUZM2a-RecE588T were first developed to co-express RecE or RecE588 and RecT for homologous recombination. Thereafter, the PCR fragments of the tetracycline resistance marker gene flanked by 60 bp of adhA (alcohol dehydrogenase I) or adhB (alcohol dehydrogenase II) homologous sequences were electroporated directly into ZM4 cells harboring pSUZM2a-RecET or pSUZM2a-RecE588T. Both adhA and adhB were replaced by the tetracycline resistance gene in ZM4, yielding two mutant strains, Z. mobilis ZM4 ΔadhA and Z. mobilis ZM4 ΔadhB. These two mutants showed varying extent of reduction in ethanol production, biomass generation, and glucose metabolism. Furthermore, enzyme activity of alcohol dehydrogenase II in Z. mobilis ZM4 ΔadhB exhibited a significant reduction compared to that of wild-type ZM4.ConclusionThis approach provided a simple and useful method for introducing mutations and heterologous genes in the Z. mobilis genome. 相似文献
12.
在机械强度好,孔隙率高、阻力小的涤纶滤布上涂覆强亲水性的聚乙烯醇材料,制备了滤布-PVA素水膜.研究了利用该膜处理油水乳化液的可行性.结果表明,在操作压力为0.05Mpa下处理质量浓度为1 000mg/L的O/W型乳化液,可获得140L/m2·h的膜通量,除油率达到82.3%. 相似文献
13.
对中国31个省级行政区2006—2011年工程勘察设计行业投入产出面板数据,采用随机前沿分析方法测定各地区的行业生产效率及其变化,并对影响行业非技术效率的因素进行定量计算和回归分析。结果表明:产出函数的技术非效率项对产出具有显著的影响,市场化程度、执业注册人数占比和规模经济同技术非效率项之间存在负向关联,而科研投入和中高级职称人数占比则对技术非效率项具有正向影响;该行业劳动力投入产出弹性(0.672 1)远大于资本投入的产出弹性(0.440 3)。 相似文献
14.
Ramesh Chander Farhan Rizvi A. K Khanna Ram Pratap 《Indian journal of clinical biochemistry : IJCB》2003,18(2):71-79
Guggulsterone, a mixture of cis (E) and trans (Z) isomers (7∶3 w/w) was synthesized from 16-DPA. The isomers were separated
by column chromatography and evaluated for cardioprotective and antioxidant activities. Myocardial necrosis induced by isoproterenol
in rats caused marked increase in serum creatine phosphokinase and glutamate pyruvate transaminase. Simultaneously in ischemic
heart, phospholipase, xanthine oxidase and lipid peroxides were enhanced following depletion of glycogen, phospholipids and
cholesterol. Treatment with guggulsterone and its both isomers at the dose of 50 mg/kg po., significantly protected cardiac
damage as assessed by the reversal of blood and heart biochemical parameters in ischemic rats. The cardioprotective activity
of guggulsterone and of both the isomers were compared with that of gemfibrozil at the same doses. Guggulsterone and both
the isomers at tested concentrations (5–20mM) inhibited oxidative degradation of lipids in human low-density lipoprotein and
rat liver microsomes induced by metal ionsin vitro. The drug counteracted against the generation of superoxide anions (O2) and hydroxyl radicals (OH−) in non-enzymic test systems. It is suggested that cardioprotective and antioxidant activities of synthetic guggulsterone
and guggulsterone obtained from gum resinCommiphora mukul that contains isomers E & Z in the ratio of 46∶54w/w are the same. 相似文献
15.
Definable surface chemistry is essential for many applications of microfluidic polymer systems. However, small cross-section channels with a high surface to volume ratio enhance passive adsorption of molecules that depletes active molecules in solution and contaminates the channel surface. Here, we present a one-step photochemical process to coat the inner surfaces of closed microfluidic channels with a nanometer thick layer of poly(ethylene glycol) (PEG), well known to strongly reduce non-specific adsorption, using only commercially available reagents in an aqueous environment. The coating consists of PEG diacrylate (PEGDA) covalently grafted to polymer surfaces via UV light activation of the water soluble photoinitiator benzoyl benzylamine, a benzophenone derivative. The PEGDA coating was shown to efficiently limit the adsorption of antibodies and other proteins to <5% of the adsorbed amount on uncoated polymer surfaces. The coating could also efficiently suppress the adhesion of mammalian cells as demonstrated using the HT-29 cancer cell line. In a subsequent equivalent process step, protein in aqueous solution could be anchored onto the PEGDA coating in spatially defined patterns with a resolution of <15 μm using an inverted microscope as a projection lithography system. Surface patterns of the cell binding protein fibronectin were photochemically defined inside a closed microfluidic device that was initially homogeneously coated by PEGDA. The resulting fibronectin patterns were shown to greatly improve cell adhesion compared to unexposed areas. This method opens for easy surface modification of closed microfluidic systems through combining a low protein binding PEG-based coating with spatially defined protein patterns of interest. 相似文献
16.
描述了湖北省神农架地区发现的石竹科一新种——神农架无心菜Arenaria shennongjiaensis Z. E. Zhao & Z. H. Shen,并绘出了线图。该种与秦岭无心菜A. giraldii (Diels) Mattf.相近,为柔弱草本,具纺锤形块根,花瓣顶端齿裂;不同之处在于其茎有1列腺毛,花瓣顶端具4齿裂,裂片又2浅裂。 相似文献
17.
描述了湖北省神农架地区发现的石竹科一新种——神农架无心菜Arenaria shennongjiaensis Z. E. Zhao & Z. H. Shen,并绘出了线图。该种与秦岭无心菜A. giraldii (Diels) Mattf.相近,为柔弱草本,具纺锤形块根,花瓣顶端齿裂;不同之处在于其茎有1列腺毛,花瓣顶端具4齿裂,裂片又2浅裂。 相似文献
18.
黄燮才 《中国科学院研究生院学报》1984,22(6):486-489
Guangdougen is generally known as Shandougen. It is a traditional
Chinese drug. It can be used as antipyretic, antidote, anodyne or antiinflammation ag-
ent. In recent years, some compounds (alkaloids, flavones and a new glycoside) such
as cytisine, matrine, oxymatrine, pterocarpin and isoprenyl chalcone, have been isola-
ted from roots of Guangdougen for medicinal purposes. They give effects of antiarrhy-
thmia, anticancer or antiulcer.
A recent investigation reveals that the Guangdougen comes from Sophora tonki-
nensis Gagnep. (syn. Sophora subprostrata Chun et T. Chen) and Sophora tonkinensis
Gagnep. var. polyphylla S. Z. Huang et Z. C. Zhou, var. nov.
Gnangdougen is geographically restricted to SE. and NW. Guangxi and SE. Gui-
zhou and Yunnan (103-109°E, 22-26°N). They have an ecological preference for li-
mestone regions, very commonly growing in mountains of 500-800 m alt. 相似文献
19.
T. A. Ajith 《Indian journal of clinical biochemistry : IJCB》2010,25(1):67-73
Iron is an essential nutrient for a number of cellular activities. However, excess cellular iron can be toxic by producing
reactive oxygen species (ROS) such as superoxide anion (O2−) and hydroxyl radical (HO·) that damage proteins, lipids and DNA. Mutagenic and genotoxic end products of lipid peroxidation can induce the decline
of mitochondrial respiration and are associated with various human ailments including aging, neurodegenerative disorders,
cancer etc. Zingiber officinale Roscoe (ginger) is a widely used spice around the world. The protective effect of aqueous
ethanol extract of Z. officinale against ROS-induced in vitro lipid peroxidation and DNA damage was evaluated in this study.
The lipid peroxidation was induced by hydroxyl radical generated from Fenton’s reaction in rat liver and brain homogenates
and mitochondrial fraction (isolated from rat liver). The DNA protection was evaluated using H2O2-induced changes in pBR-322 plasmid and Fenton reaction-induced DNA fragmentation in rat liver. The results indicated that
Z. officinale significantly (P<0.001) protected the lipid peroxidation in all the tissue homogenate/mitochondria. The extract
at 2 and 0.5 mg/ml could protect 92 % of the lipid peroxidation in brain homogenate and liver mitochondria respectively. The
percent inhibition of lipid peroxidation at 1mg/ml of Z. officinale in the liver homogenate was 94 %. However, the extract
could partially alleviate the DNA damage. The protective mechanism can be correlated to the radical scavenging property of
Z. officinale. The results of the study suggest the possible nutraceutical role of Z. officinale against the oxidative stress
induced human ailments. 相似文献
20.
Photocatalytic water purification using visible light is under intense research in the hope to use sunlight efficiently, but the conventional bulk reactors are slow and complicated. This paper presents an integrated microfluidic planar reactor for visible-light photocatalysis with the merits of fine flow control, short reaction time, small sample volume, and long photocatalyst durability. One additional feature is that it enables one to use both the light and the heat energy of the light source simultaneously. The reactor consists of a BiVO4-coated glass as the substrate, a blank glass slide as the cover, and a UV-curable adhesive layer as the spacer and sealant. A blue light emitting diode panel (footprint 10 mm × 10 mm) is mounted on the microreactor to provide uniform irradiation over the whole reactor chamber, ensuring optimal utilization of the photons and easy adjustments of the light intensity and the reaction temperature. This microreactor may provide a versatile platform for studying the photocatalysis under combined conditions such as different temperatures, different light intensities, and different flow rates. Moreover, the microreactor demonstrates significant photodegradation with a reaction time of about 10 s, much shorter than typically a few hours using the bulk reactors, showing its potential as a rapid kit for characterization of photocatalyst performance. 相似文献