Bioactivity and constituents of several common seaweeds

Bioactivity and constituents of 8 common seaweeds from Dalian intertidal zone of northern Yellow Sea were investigated. In the anti-methicillin-resistant Staphylococcus aureus (MRSA) test, Symphyocladia latiuscula and Enteromorpha intestinalis showed obvious activities with MICs much lower than 1.0 mg·mL-1 . In the DNA damage repair test (DDRT), Chondrus ocellatu showed selective inhibitory activity against the DNA repair-defective E. coli strain vs. the wild-type E. coli strain; while Sym. latiuscula, Enteromorpha intestinalis and Sar. kjellmanianum showed significant anti-E. coli activity with MICs of 64-128 g·mL-1 . In the anti-Pyricularia oryzae test, Sym. latiuscula and Rh. confervoides strongly inhibited the germination of the spores of P. oryzae on agar plate. In the brine shrimp larvicidal test, Sym. latiuscula, Rh. confervoides and Sar. kjellmanianum exhibited potent toxicity against brine shrimp larvae, with LC50 much lower than 1 mg·mL-1 . The HPTLC analysis revealed their diversified secondary metabolites. The HPLC-DAD-MS analysis of the strongest species Sym. latiuscula and database searching showed that it can produce quite diversified metabolites, including halogenated ones, some of which may be new natural products. The results demonstrated the potentials of these seaweeds in the development of new antibiotics, antitumor drugs, agricultural fungicides and pesticides.     

(1→3)-α-D葡聚糖的季铵盐合成及其抗菌活性(1→3)-α-D葡聚糖的季铵盐合成及其抗菌活性

来源于Penicillium chrysongenum的碱溶性 (1→3)-α-D葡聚糖与缩水甘油基三甲基季铵盐酸盐（glycidyl trimethylammonium chloride, GTMAC）反应，生成葡聚糖季铵盐。IR图谱中季铵基团上的甲基的变角振动峰1480cm^-1、伸缩振动峰2872cm^-1变化明显，¹H-NMR表征确定季铵基团在糖环2、4位连接。该葡聚糖的最低抑菌浓度对大肠杆菌为1.0mg/mL，对金黄色葡萄球菌为2.0mg/mL。细胞质释放检测结果显示，葡聚糖季铵盐通过作用于细菌细胞膜而发挥抗菌作用。     

Photoautotrophic Growth and Net Photosynthetic Rate of Sweet Potato Plantlets In Vitro as Affected by the Number of Air Exchanges of the Vessel and Type of Supporting Material

Introduction Micropropagation, a plant tissue culture technique, has contributed to producing virus-free, genetically supe-rior plantlets. However, its commercial application is still limited due to its relatively high production costs. The high costs are…     

Antibacterial activity and structure-activity relationships of Schiff bases on <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> by microcalorimetry

The growth of Staphylococcus aureus under the action of six kinds of Schiff bases(A,B,C,D,E,F) was studied by means of microcalorimetry. Growth constant k and inhibition ratio I were calculated. Also,the antibacterial activity,the action characteristics and the structure-activity relationships of the compounds on S. aureus were analyzed. Results indicate that B,F show good antibacterial activity(IC50:293.6 mg · L-1 and 307.8 mg · L-1) ,D,E show moderate antibacterial activity(IC50:966.3 mg · L-1 and 1 126.7...     

InAsSb thick epilayers applied to long wavelength photoconductors

InAs_0.052Sb_0.948 epilayers with cutoff wavelengths longer than 8 μm were successfully grown on InAs substrates using melt epitaxy (ME). Scanning electron microscopy observations show that the interface between the epilayers and substrates is flat, indicating the good quality of the epilayers, and the thickness of the epilayers is 40 μm. Photoconductors were fabricated using InAs_0.052Sb_0.948 thick epilayers grown by ME. Ge optical lenses were set on the photoconductors. At room temperature, the photoresponse wavelength range was 2–10 μm. The peak detectivity D_λp* reached 5.4 × 109 cm·Hz1/2·W?1 for the immersed detectors. The detectivity D* was 9.3 × 108 and 1.3 × 108 cm·Hz1/2·W?1 at the wavelength of 8 and 9 μm, respectively. The good performance of the uncooled InAsSb detectors was experimentally validated.     

基于反应体系的表面增强拉曼光谱快速检测乙基麦芽酚

以铁离子(Fe~(3+))为媒介,鞣酸还原氯金酸制备的金纳米粒子(Au NPs)作为表面增强拉曼散射(SERS)基底,实现比色-散射光谱双响应,快速鉴别食品中的乙基麦芽酚.其中比色法中,对乙基麦芽酚的检测限为0.50 mg·mL~(-1).SERS检测中,利用Fe~(3+)和乙基麦芽酚的络合作用,乙基麦芽酚的最低检测限降低到0.01 mg·mL~(-1),线性范围为0.05～1.00 mg·mL~(-1).该方法使用的仪器简单,操作方便,可对样品中的乙基麦芽酚进行现场直接测定.     

Flow-injection microcolumn on-line preconcentration for the determination of chromium (VI)

A rapid and sensitive on-line preconcentration method for spectrophotometric determination of chromium (VI) in nature water is described. Preconcentration and determination are based on (i) the quantitative and fast adsorption of chromium (VI) on the high surface area nanometer-size TiO₂ (anatase) powders, which prepared by a sol-gel method from hydrolysis of TiCl₄ and (ii) the quantitative and reproducible elution of Cr (VI) by 2.0 mol·L⁻¹ HCl. A mini-column system for preconcentration is developed, Cr(VI) on the mini-column is eluted and merged with a stream water and DPCB (1,5-diphenylcarbazide) as the chromogenic reagent. The proposed system permits throughputs of 6 sample h⁻¹ (0.001 μg·mL⁻¹ Cr(VI)) or 20 sample h⁻¹ (0.1 μg·mL⁻¹ Cr(VI)). The preconcentration factor is 55. The detection limit is 0.8 ng · mL⁻¹ Cr(VI). The reproducibility is satisfactory with a relative standard deviation of less than 3.35% (0.01 μg·mL⁻¹ Cr(VI),n=5). Supported by the National Natural Science Foundation of China Ma Wanhong: born in 1961, Ph. D. Graduate student, Associate professor     

Efficient transfer and expression of human clotting factor IX cDNA in neonatal hemophilia B mice mediated by VSV-G pseudotyped retrovirus

The feasibility of in vivo gene therapy for hemophilia B by VSV-G pseudotyped retroviral vector was introduced. The novel packaging cell line 293GPG was used to produce VSV-G/G1NaBAIX pseudotyped virus with the highest titers up to 8.5×10⁸ cfu·mL^-1. In contrast to the conventional retrovirus, VSV-G pseudotyped virus was more resistant to inactivation by serum complements (P＜0.001). Our results also demonstrated that VSV-G pseudotyped virus was more stable in neonatal mice serum than in adult mice serum (P＜0.01). After intraperitoneal injection of different doses of virus, hFIX antigen was detected and lasted for more than 120 d, the highest level reached (72.5±6.1) ng·mL^-1. Moreover, the functional activity was improved to some extent in all hFIX-treated mice, the most remarkable improvement was observed in the mice treated with higher dose of virus whose clotting activity increased to (3.4±1.5)% and APTT (activated partial thromboplastin time) reduced to (43.2±7.2) s. The anti-hFIX antibody was not detected by the method of Bethesda, no germ line transmission and any side effects associated with gene transfer were found. Our results indicated that neonatal gene therapy for hemophilia B mice by VSV-G pseudotyped retrovirus is promising.     

SBDR显色剂固相萃取光度法测烟草中的铅

 研究了对磺酸基苯基亚甲基若丹宁(SBDR)与铅的显色反应,在pH为4.0的HAc-NaAc缓冲介质中,吐温-60存在下,该络合物可被WatersSep-Pak-C18固相萃取小柱萃取,小柱上富集的络合物用无水乙醇洗脱后在乙醇介质中,体系λ_max=560nm,ε=1.12×10⁵L·mol^-1·cm^-1.可用分光光度法测定,铅含量在0~6μg/50mL内符合比尔定律,方法用于烟草中铅含量的测定,结果令人满意.     

不同生长调节剂提高香荚兰抗逆能力的研究

 研究了6种不同生长调节剂脱落酸(abscisic acid,ABA,5μg·L^-1)、膨大剂(CPPU,5μg·L^-1)、那氏试剂(778诱导剂,5×10⁶μg·L^-1)、烯效唑(uniconazole,10μg·L^-1)、长效BR-120(0.2μg·L^-1)、几丁质(chitin,10μg·L^-1)喷施香荚兰植株对其抗逆能力的影响.结果表明:各种处理后叶片内超氧化物歧化酶(SOD)、过氧化物酶(POD)活性提高和丙二醛(MDA)含量降低.其中,烯效唑的效果最佳,其次为BR-120,其它调节剂也有一定的作用效果此外,还对ABA处理后随取样时间不同植株抗逆能力的变化作了初探.     

犁头草抗菌活性及其有效部位研究

本实验将犁头草全草作为研究对象,采用不同方法对犁头草全草的有效成分进行提取,评价并比较各提取物的抗菌活性。并将粗提物按照极性高低分布在石油醚、乙酸乙酯和水相中,评价不同萃取相的抗菌活性。结果显示,乙醇回流法和甲醇冷浸法获得的提取物抗菌活性明显,而水煎煮得到的提取物几乎未见抗菌活性。此外,乙酸乙酯萃取相的抗菌作用要优于石油醚相,而水萃取相抗菌活性最小。甲醇冷浸法和乙醇回流法获得的乙酸乙酯萃取组对金葡菌ATCC 33591和金葡菌ATCC 43300的抗菌活性最佳,最小抑菌浓度（MIC）值达到0.3125 mg/mL,对其他细菌的MIC值在0.3125~1.25 mg/mL之间;而其他萃取组分对金葡菌、枯草芽孢杆菌、铜绿假单胞菌以及耐药菌的MIC值大约在1.25~5 mg/mL之间。本研究确定了犁头草具有广谱的抗菌活性,尤其对耐甲氧西林金葡菌效果较好。研究发现乙醇回流与甲醇冷浸法可用于犁头草的抗菌物质提取,且它的抗菌有效部位为乙酸乙酯萃取相。     

Effect of irrigation with saline water on soil water-salt dynamics and maize yield in Arid Northwest China

An experiment was conducted in non-weighing lysimeters to study the effect of irrigation with saline water on water movement and salt accumulation and maize yield. The experiment was carried out in northwest China,both sufficient and insufficient irrigation were applied in the first year,and only sufficient treatments in the second year. Irrigation with solute concentration of 9 g·L-1 and 6 g·L-1 led to salt accumulation about 6-8 dS·m-1 in certain depths,even downwards to 160 cm received about 4 dS·m-1 for 9 g·L-1 and 2 dS·m-1 for 6 g·L-1,which was two times more than initial. Salt-affected water extracted from soil behaved as low evapotranspiration under sufficient irrigation,and more water was left in the soil. Yield of spring maize was not affected when saturated soil paste electrical conductivity did not exceeded 1.2 dS·m-1.     

Sensitive Determination of DNA by RLS Enhancement of Metal Ions

0　IntroductionThequantitativeanalysisofnucleicacids,especiallythemi cro determinationofnucleicacids,isbecomingmoreandmoreimportantinmanybiologicalstudies.Recently ,apromisingspectraltechnique ,whichwasbasedonthemeasurementofen hancedresonancelightscattering (RLS) [1 ,2 ] ,hasgivenrisetostronginterestbyanalystsandbiochemistsfornucleicacidsandproteinassay[3 9] .Uptonow ,manykindscompoundshavebeenfoundRLSenhancementwhilebindingtoDNA ,andallthesecompoundsarecharacterizedofpositivechargewhicha…     

Effects of zinc on physiologic characterization and cadmium accumulation and chemical forms in different varieties of pepper

The effects of zinc(Zn) at different spray concentrations(0, 500, and 1 0001μmol L) on the plant growth, the activities of antioxidant enzymes chemical forms of cadmium(Cd), and the accumulation of Cd were studied and compared between two varieties, Shijichaotianjiao(SJCTJ) and Yanjiao425(YJ425) of pepper(Capsicum annuum L.) in Cd-contaminated soil(Cd 10 1mg kg). The activities of catalase(CAT) and peroxidase(POD) were generally enhanced by Zn. However, superoxide dismutase(SOD) decreased. Addition of Zn decreased the ethanol-extractable Cd, NaCl-extractable Cd, and acetic acid-extractable Cd in the fruit by 34.6%- 55.3%, 2.0%-17.7% and 0.4%-32.9%, and reduced the accumulation of Cd in fruit and plant total Cd by 12.8%- 68.6% and 9.0%-29.3% in both varieties, respectively.     

Kinetic analysis and strain-compensated constitutive models of Ti-42.9Al-4.6Nb–2Cr during isothermal compression

The hot deformation behavior of Ti-42.9Al-4.6Nb–2Cr (at. %) was investigated by isothermal compression tests at the deformation temperature range of 1373–1573 K, strain rate range of 0.001–1.0 s⁻¹, up to the strain of 0.69. The flow stress test results of Ti-42.9Al-4.6Nb–2Cr showed negative temperature and positive strain rate sensitivity. Besides, strain had a great effect on the hot deformation behavior of Ti-42.9Al-4.6Nb–2Cr. Kinetic analysis was adopted to assess the hot workability of Ti-42.9Al-4.6Nb–2Cr via apparent activation energy (Q) of hot deformation, strain-rate sensitivity index (m) and strain hardening index (n). The Q value varied from 607.1 ± 0.7 kJ·mol⁻¹ to 512.6 ± 10.8 kJ mol⁻¹ with the increasing of strain from 0.1 to 0.6. The effect of strain on the Q value at the deformation temperatures below 1473 K was mainly related to dynamic recrystallization of γ phase and kinking of γ lamellae, while the Q value at the deformation temperature above 1473 K might be linked to γ→α phase transformation and DRV of α phase. Based on the kinetic analysis, strain-compensated Arrhenius model and Hensel-Spittel model were successfully established to predict the hot workability (flow stress). Average absolute relative errors of established strain-compensated Arrhenius model and Hensel-Spittel model were 7.52% and 11.95%, respectively. Moreover, both established constitutive models can be extrapolated for predicting the flow stress of Ti-42.9Al-4.6Nb–2Cr to larger strain levels.     

Dynamic recrystallization behavior of the Ti–48Al–2Cr–2Nb alloy during isothermal hot deformation

The hot deformation behavior of the as-cast Ti–48Al–2Cr–2Nb alloy was investigated by isothermal compression tests at deformation temperatures ranging from 1000℃ to 1200℃,and strain rates from 0.001 s~(-1)to 0.1 s~(-1).The single peak stress features common to all flow curves indicate that DRX is the dominating softening mechanism.The calculated values of the hot deformation activation energy Q and stress index n are 296.5 kJ mol~(-1)and 3.97,respectively.Based on this,the Arrhenius type constitutive equation was successfully established.The DRX critical condition model and relationship among DRX volume fractions,deformation temperatures and strain rates were obtained to optimize the process.Combined with microstructure analysis,it's concluded that 1200℃/0.01s~(-1)is the optimization parameter.Besides,both DDRX and CDRX were observed in theγphase evolution.The deformation mechanism from the inter-grain dislocation motion to the grain boundary migration and grain rotation was discussed.     

On a Reduction of the Kadomtsev-Petviashvili Hierarchy

Introduction Many (1 1)-dimensional integrable systems can be re- duced from the Kadomtsev-Petviashvili (KP) hierarchy, with the most typical examples including the Gelfand- Dickey hierarchy (N-Korteweg de Vries (KdV) hierar- chy)[1] and the so called con…     

Synthesis of glass ceramics from kaolin and dolomite mixture

Cordierite-and anorthite-based binary glass ceramics of the CaO-MgO-Al₂O₃-SiO₂ (CMAS) system were synthesized by mixing local and abundant raw minerals (kaolin and doloma by mass ratio of 82/18). A kinetics study reveals that the activation energy of crystallization (Ea) calculated by the methods of Kissinger and Marotta are 438 kJ·mol-1 and 459 kJ·mol-1, respectively. The Avrami parameter (n) is estimated to be approximately equal to 1, corresponding to the surface crystallization mechanism. X-ray diffraction (XRD) analysis shows that the anorthite and cordierite crystals are precipitated from the parent glass as major phases. Anorthite crystals first form at 850℃, whereas the μ-cordierite phase appears after heat treatment at 950℃. Thereafter, the cordierite allotropically transforms to α-cordierite at 1000℃. Complete densification is achieved at 950℃; however, the density slightly decreases at higher temperatures, reaching a stable value of 2.63 kg·m-3 between 1000℃ and 1100℃. The highest Vickers hardness of 6 GPa is also obtained at 950℃. However, a substantial decrease in hardness is recorded at 1000℃; at higher sintering temperatures, it slightly increases with increasing temperature as the α-cordierite crystallizes.     

药物中半胱氨酸的流动注射荧光测定方法研究

 在近中性介质及聚乙烯醇(PVA)存在下,半胱氨酸能熄灭一个新的荧光试剂5-(4-氯苯基)-8-苯磺酰氨基喹啉(CPBSQ)与Cu(Ⅱ)络合体系的荧光的反应.基于此现象,本文建立了一个测定半胱氨酸的流动注射荧光熄灭方法.结果表明,在λ_ex/λ_em=327/368nm处测定,方法的进样频率为64h-1,检测范围为0.05～5.5μg·mL^-1,检出下限为0.01μg·mL^-1,对4.0μg·mL^-1半胱氨酸平行测定11次的相对标准偏差为1.52%.大量存在的常见金属离子、蛋白质及很多不带巯基的氨基酸不干扰测定.应用此方法测定了某些注射液针剂中半胱氨酸的含量,结果满意.     

Isothermal Kinetics of the Pentlandite Exsolution from mss/Pyrrhotite Using Model-Free Method

Introduction Pyrrhotite(Fe,Ni)1?xS and pentlandite(Fe,Ni)9S8areimportant constituents of primary nickel sulfide oredeposits.Pentlandite is invariably associated with pyr-rhotite.At high temperatures(above610℃)(Fe,Ni)1?xS has the NiAs structure and is kno…