一例产前Silver-Russell综合征胎儿的基因变异分析

目的:对1例产前B超提示骨骼系统发育异常,疑似宫内生长受限的胎儿进行基因检测及生物信息学分析以明确其致病原因。方法:采集胎儿羊水及父母外周血,提取基因组DNA,利用高通量测序平台进行家系全外显子组测序(whole exome sequencing,WES)及拷贝数变异测序(copy number variation sequencing,CNV-seq)技术检测,可疑结果经Sanger测序进行验证。结果:胎儿高迁移率族蛋白A2(high mobility group protein AT-Hook-2,HMGA2)基因存在c.223C>T(p.R75W)新发变异,导致氨基酸改变为p.R75W(p.Arg75Trp),为错义突变。根据美国医学遗传学与基因组学学会(American College of Medical Genetics and Genomics,ACMG)指南评级,该变异判定为可能致病性(likely pathogenic):PS2+PM2_Supporting+PP3+PS4_Supporting。根据其临床表型,该胎儿被确诊为常染色体显性遗传的Silver-Russell综合征5型(Silver-Russell syndrome 5,SRS5)。Sanger测序确证了其变异的真实性。结论:HMGA2基因的c.223C>T(p.R75W)杂合致病性变异可能是SRS5的遗传学致病原因,扩充了该基因的变异谱,同时为该胎儿的产前遗传咨询和后续的干预措施提供了理论依据。

两例Silver-Russell综合征的临床特征和H19印迹基因甲基化分析

目的探讨Silver-Russell综合征的遗传学异常，提高对该病的认识并指导临床诊断。方法以2例疑似Silver-Russell综合征患者为研究对象，详细采集病史并进行归纳，同时取其外周血用基因组DNA试剂盒提取DNA并用亚硫酸氢盐转化处理，然后用PCR扩增目标序列，采用焦磷酸测序法检测11P15区的H19印迹基因上游的DMR区的甲基化状态。另收集10例健康儿童外周血标本作为对照组。结果2例患儿的临床特征及辅助检查均符合Silver-Russell综合征临床诊断，所测的H19印迹基因上游的DMR区6个甲基化位点的甲基化水平分别为16％～21％和15％-23％，该区域均表现出低甲基化状态；而正常对照组的6个甲基化位点的甲基化水平为48％～55％，明显高于病例组。结论Silver-Russell综合征临床表现多样，运用焦磷酸测序技术联合甲基化分析操作方便、定量准确，可考虑对临床诊断或疑似Silver-Russell综合征病例运用该技术进行检测。

Silver-ion HPLC测定1,3-二油酸-2-棕榈酸三酰甘油的含量

准确测定1,3-二油酸-2-棕榈酸三酰甘油(OPO)的含量,建立了一种以高效液相色谱结合银离子交换柱(Silver-ion HPLC)的测定方法。以ChromSpher 5 Lipid(25 cm×4.6 mm,5μm)银离子交换柱通过HPLC正相系统分离三酰甘油,配合蒸发光散射检测器(ELSD),以毒性较小的二氯甲烷和丙酮为流动相。流速0.6 mL/min,柱温30℃。漂移管温度30℃,空气压力0.35 MPa。在此条件下,1,3-二油酸-2-棕榈酸三酰甘油和1,2-二油酸-3-棕榈酸三酰甘油两种同分异构体基本达到分离,样品出峰完整,峰形良好。OPO色谱峰面积的自然对数与浓度的自然对数呈良好的线性关系(R2=0.998 8)。用该方法测定了母乳脂肪、实验室合成结构油脂样品、商品结构油脂、棕榈油和山茶油中OPO的含量。结果表明该方法的灵敏度高、重现性良好。

Antibacterial and Preservation Effects of Silver-doped TiO_2 Nanoparticles on Nanfeng Citrus

[Objective] This study aimed to investigate the antibacterial and preservation effects of silver-doped nano-TiO2 on Nanfeng citrus. [Method] Silverdoped nano-TiO2 preservative film was prepared, to investigate its preservation effects on Nanfeng citrus ripe fruits under novel preservation conditions and detect the influences of nano-composite coating on physiological quality indicators of Nanfeng citrus ripe fruits. [ Result ] Compared with the control, applying nano-compesite coating preservation technology could prevent fruit corruption and water loss and delay the rapid reductioh in contents of citric acid and Vc, without adverse influences on fruit quality. [ Conclusion] Silver-doped nano-TiO2 composite coating can be promoted and applied in frozen storage and preservation practices of Nanfeng citrus.

Long-term Antibacterial Properties and Bond Strength of Experimental Nano Silver-containing Orthodontic Cements

The purpose of this study was to evaluate the long time antibacterial properties and shear bond strength of experimental nano silver-containing cements （NSC）. Nano silver base inorganic antibacterial powder was added to the reinforced glass ionomer cement at five different weight ratios to obtain a series of nano silver-containing cements, then the antibacterial properties of three orthodontic cement products and five NSC samples were evaluated by the direct contact test （DCT） and the agar diffusion test （ADT）. The DCT, which was based on turbidness determination of bacterial growth in 96-well microtiter plates, was performed in both fresh and aged for 1 day, 1 week, 2 weeks, 3 weeks, 4 weeks, 6 weeks, and 8 weeks tested materials. The shear bond strengthes of three orthodontic cement products and five NSC samples were examined using a universal testing machine. The ADT results indicated that there were no significant differences between NSCs and ORTHO LC fresh specimens. In the DCT experiment, all fresh silver nanoparticles-containing tested samples presented powerful antibacterial properties, but they gradually lost the effective antimicrobial agents with the extension of aging time. Finally, none of the tested materials maintained its antibacterial property after aging for 8 weeks. A gradually decreasing trend of bond strength presented with the increasing incorporation of nano silver base inorganic antibacterial powder into the glass ionomer cement, even though all the tested material specimens reached the ideal bond strength range. We may conclude that NSCs can contribute to decrease the demineralization rate around brackets without compromising bond strength.

Mechanism of silver-influenced bacterial leaching of chalcopyrite, pyrite and a copper ore

The silver catalyzed bioleaching of chalcopyrite, pyrite and a chalcopyrite containing ore from Dexing Copper Mine (China) was investigated. It has been found that silver ions selectively accelerated the rate of copper dissolution from the ore while suppressed the iron leaching. Adding 2.0 g Ag per kg mineral, the copper recovery from chalcopyrite increased from 29.2% (without a catalyst) up to 78.4%, while the iron recovery decreased from 51.0% (no silver) to 27.4%, in the presence of microorganisms. It is believed that the enhancement of chalcopyrite bioleaching by Ag + ions is attributed to the formation of an intermediate, Ag 2S, which was confirmed by X ray diffraction of the solid leach residue of chalcopyrite and the analyses of the cyclic voltammetry for CuFeS 2 electrodes in silver containing 9 K medium. The inhibition of pyrite biooxidation is owing to the formation of metallic silver on the pyrite surface instead of Ag 2S, which was detected by X ray photoelectron spectroscopy (XPS).

NON-POLLUTION PROCESS FOR COMPLEX REFRACTORY SILVER-GOLD ORES

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Research on arc erosion of silver-based alloy contact materials under low voltage,resistive load and small current at 400 Hz and 50 Hz

By using a self-developed IF power and a ASTM contact material experimental system of small-capacity and variable frequency,the value of arcing characteristics and the welding force of the silver-based contact material are acquired under low voltage,resistive load and small current at 400 Hz and 50 Hz. By means of an electricity-ray analytical balance,SEM and EDAX,the weighing values of the contact materials and the changes of AgCdO,AgNi,AgC and AgW contact material surface profile and micro-area constituent are obtained and analyzed. The arc erosion causes of silver-based alloy contact materials at 400 Hz and 50 Hz are also discussed.

Tectonic Dynamic Metallization of Silver-GoldHydrothermal Fluids in Proterozoic GneissTerrene Shear Zones, Suichang, Zhejiang, China

The Suichang mine is the largest silicified vein-type silver-gold mineralization system in Southeast China, whose ore bodies are controlled by shear zones developing in Lower Proterozoic gneiss terrene with initial migmatization, which is covered by Upper Jurassic and Lower Cretaceous volcanic rock system and cut by acidic igneous veins of Jurassic and Cretaceous. The conclusions are as follows: (1) The ore-forming fluid is defined as superhigh tectonic-metamorphic fluid on the base of : 1 (D)-(18O) values 2 fluid inclusions;3 trace elements of pyrite from ores. (2) The shear zone silicified orebod-ies occurred in proterozoic, Jurassic and Cretaceous, which have been transforms in part by ore-bearing comb quartz vein of volcanism.

Antibacterial Properties of Nano Silver-containing Orthodontic Cements in the Rat Caries Disease Model

The purpose of this study was to evaluate the antibacterial properties of experimental nano silver-containing cements（NSCs） using rat caries disease model. Nano silver base inorganic antibacterial powder was added to the reinforced glass ionomer cement at three different weight ratios to obtain a series of nano silver-containing cements, then two orthodontic cement products and three NSC samples were implanted into rat caries disease model, and their antibacterial properties were evaluated by the scanning electron microscope（SEM）. Moreover, the rat caries disease model were established by inoculating cariogenic bacteria S mutans into antibiotics treated rat mouths and feeding with cariogenic diet. The tested materials were bonded on the surface of the buccal half crowns of the upper fi rst premolar, and then fi xed under the rats＇ front teeth lingual side to acquire enough retention. The SEM results indicated that the growth of streptococcus mutans was very active in group of Transbond XT. One month later, S mutans scattered on the GC Fuji ORTHO LC surface, and then the number signifi cantly increased and arranged in chains after three months. In groups of NSC2, NSC3 and NSC4, the number of S mutans presented the downward trend and tended to disperse individually with the increase of silver nanoparticle content. We may conclude that the incorporation of silver nanoparticle enhanced GC Fuji ORTHO LC the adhesion restrain and killing effect to S mutans.

Influence of Gadolinium with Small Content on Recrystallization Behaviour in Silver-Gold Alloys

The influence of small addition of RE element Gd on recrystallization behaviour in isomorphous Ag-Au alloys was studied by differential scanning calorimetry, optical microscopy, transmission electron microscopy and hardness measurement. It is shown that in alloys with 0.2% Gd, disperse second-phase particles are formed, which results in obvious increase in the recrystallization temperature and grain refining. The recrystallization temperature of AgAuGd0.2 alloys also increases with cold working. Small addition of Gd raises the apparent activation energy of recrystallization for Ag-Au alloys.

Silver-Russell综合征研究进展

Silver-Russell综合征是一组遗传异质性的疾病,主要临床表现为胎儿严重的宫内生长发育迟缓及出生后生长发育迟缓和矮身材。1953年Silver等首先报道报告了2例先天性的躯体不对称、低体重、矮身材、尿中促性腺激素增高的病例。以后陆续有零散病例报告。目前研究发现此病有三种遗传方式:即母源第7号染色体单亲双体、常染色体显性遗传及常染色体隐性遗传。本文综述了Silver-Russell综合征的临床诊断标准及研究进展。

Synthesis of 4A Zeolite and Characterization of Calcium- and Silver-Exchanged Forms

Calcium exchanged A type zeolite is extensively used as an adsorbent in petroleum and gas purification application. The precursor of calcium and silver-exchanged zeolite was prepared in a hydrothermal process, followed by an exchange process. In this study, LTA zeolite was synthesized. Calcium-ex- changed and silver-exchanged molecular sieves were prepared and characterized by a series of techniques, such as scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, etc. Physical properties of Ca- and Ag-exchanged zeolite A, such as surface structure, crystal structure, cation exchange capacity, and the ion-exchange properties were measured. Water adsorption studies using thermogravimetric method indicated that water molecules are more strongly bound in the Ca-A zeolite compared to Ag-A zeolite. XPS studies confirmed the presence of highly dispersed cationic silver species at exchange sites. The results of this study indicated that sodium was successfully exchanged with the calcium and silver in both Ca- and Ag-ex- changed zeolite frameworks. High cation exchange capacity, tailored aperture size, high porosity and specific surface area, as well as high thermal stability make cation-exchanged A type zeolite a successful candidate for adsorption, ion exchange, and catalysis applications.

Effect of Silver-Loaded Zeolite on the Susceptibility of <i>Escherichia Coli</i>Against Antibiotics

We investigated the effect of silver-loaded zeolite (Ag-Z) on antibacterial activity of some antibiotics against Es-cherichia coli against antibiotics. We treated the bacterial suspension of E. coli by Ag-Z to be the level which the decrease of viable cell count was not observed. Susceptibility test of E. coli treated with Ag-Z was carried out against four antibiotics with different mode of action. Apparent increase in susceptibility was found in the case of rifampicin, not in others. The result suggests that application of Ag-Z to ward environment might give a good outcome at the treatment with rifampicin and at the treatment for pathogenic microbe spread through the air, such as tubercle bacilli.

Anionic Nanochanneled Silver-Deficient Oxalatochromate(III) Complex with Hydroxonium as Counter Ion: Synthesis, Characterization and Crystal Structure

Reaction of Ba0.50[Ag2Cr(C2O4)3]·5H2O with Ag2SO4 in an aqueous solution of sulfuric acid (pH ≈ 3) yielded the silver(I)/chromium(III) oxalate salt H0.50[Ag2.50Cr(C2O4)3]·5H2O (1). Compound 1 can be best described as an anionic silver-deficient oxalatochromate(III) complex [Ag2.50Cr(C2O4)3]0.5- with nanochannels containing hydrogen-bonded water molecules and protons. Thermal analyses show significant weight losses corresponding to the elimination of water molecules of crystallization followed by the decomposition of the network.

Separation of silver from silver-manganese ore with cellulose as reductant

The silver in some silver-manganese ore with a grade of 3.15×10?4 was concentrated by a combined beneficiation technique including magnetic separation, flotation, reducing leaching and gravity desliming. The major silver contained in manganese ore as isomorphism was concentrated by magnetic separation, while around 8.50% of the silver individual minerals were separated by flotation. The manganese in the mixed concentrate of both magnetic separation and flotation was dissolved in a reducing leaching, in which some cellulose reductant named CMK was used. Part of the slime contained in leach residue was removed by a laboratory desliming equipment. A silver concentrate with a grade of 4.96×10?3 Ag and a recovery of 84.25% were obtained.

Silver-nanoparticle-coated biliary stent inhibits bacterial adhesion in bacterial cholangitis in swine

BACKGROUND： One of the major limitations of biliary stents is the stent occlusion, which is closely related to the over- growth of bacteria. This study aimed to evaluate the feasibility of a novel silver=nanoparticle-coated polyurethane （Ag/PU） stent in bacterial cholangitis model in swine. METHODS： Ag/PU was designed by coating silver nanopar- tides on polyurethane （PU） stent. Twenty-four healthy pigs with bacterial cholangitis using Ag/PU and PU stents were ran- domly divided into an Ag/PU stent group （n=12） and a PU stem group （n=12）, respectively. The stents were inserted by standard endoscopic retrograde cholangiopancreatography. Laboratory assay was performed for white blood cell （WBC） count, alanine aminotransferase （ALT）, interleukin-1 [l （IL- 1 p）, tumor necrosis factor-a （TNF-~） at baseline time, 8 hours, 1, 2, 3, and 7 days after stent placements. The segment of bile duct containing the stent was examined histologically ex vivo. Implanted bili- ary stents were examined by a scan electron microscope. The amount of silver release was also measured in vitro. RESULTS： The number of inflammatory cells and level of ALT, IL-1β and TNF-α were significantly lower in the Ag/PU stent group than in the PU stent group. Hyperplasia of the mucosa was more severe in the PU stent group than in the Ag/PU stent group. In contrast to the biofilm of bacteria on the PU stent, fewer bacteria adhered to the Ag/PU stent. CONCLUSIONS： PU biliary stents modified with silver nanoparticles are able to alleviate the inflammation of pigs with bacterial cholangitis. Silver-nanoparticle-coated stents are resistant to bacterial adhesion.

Improvement of flotation behavior of Mengzi lead-silver-zinc ore by pulp potential control flotation

The electrochemical behavior of Mengzi lead-silver-zinc ore flotation system was studied. Based on the electrochemical characteristics of sulfide mineral flotation system, a stage potential control flotation was developed with the main parameters of pulp potential(φp), pH value and collector dosage. Using N,N’ diphenylamino-dithiolphosphoric acid(NNDDC) as a collector, which has good selectivity for galena flotation at pH 8.8 and pulp potential 330 mV, DDTC is used as secondary collector to improve both the grade and recovery of Pb and Ag. The pulp potential values significantly influence the floatability of practical minerals and single minerals when using NNDDC as the collector. The flotation recovery of galena reaches 85% at about 0.3 V and pH8.8. With the usage of pulp potential control during grinding and flotation, the new pulp electrochemical technology for Mengzi lead-silver-zinc ore flotation was developed. The results show that the grades of Pb and Ag of galena concentrate are 55% and 1 800 g/t, respectively, while the recoveries of Pb and Ag are 86.5% and 65%, respectively, the grade of Zn of marmatite concentrate is 42.5%, and the recovery of Zn is 91.25%.

Lubrication properties of silver-palladium alloy prepared by ion plating method for high temperature stud bolt

As a solid lubricant, silver-palladium (Ag-Pd) alloy coating was investigated for the application to high temperature stud bolt. A glue layer nickel (Ni) film was deposited on the surface of the hex bolt sample and then Ag-Pd alloy coating was performed on it using ion plating method. The friction coefficient of Ag-Pd alloy film coated bolt was lower than that of N-5000 oil coated bolt by the result of axial force measurement. The cyclic test of heat treatment was conducted to evaluate the durability of Ag-Pd alloy film coated bolt. In a cycle, sample was assembled into the block using torque wrench, followed by heating and disassembling. It was not successful to disassemble the N-5000 oil coated bolt from the block after only one cycle. However, the Ag-Pd alloy film coated bolt was able to be disassembled softly till 12 cycles.

Silver-palladium alloy deposited by DC magnetron sputtering method as lubricant for high temperature application

The silver-palladium(Ag-Pd) alloy coating as a solid lubricant was investigated for its application to the high temperature stud bolts used in nuclear power plants.A hex bolt sample was prepared in the following steps:1) bolt surface treatment using alumina grit blasting for cleaning and increasing the surface area;2) nickel(Ni) film coating as a glue layer on the surface of the bolt;and 3) Ag-Pd alloy coating on the Ni film.The films were deposited by using a direct current(DC) magnetron sputtering system.The thickness and composition of the Ag-Pd alloy film have effect on the friction coefficient,which was determined using axial force measurement.A 500 nm-thick Ag-Pd(80-20,molar ratio) alloy film has the lowest friction coefficient of 0.109.A cyclic test was conducted to evaluate the durability of bolts coated with either the Ag-Pd(80-20) alloy film or N-5000 oil.In a cycle,the bolts were inserted into a block using a torque wrench,which was followed by heating and disassembling.After only one cycle,it was not possible to remove the bolts coated with the N-5000 oil from the block.However,the bolts coated with the Ag-Pd(80-20) alloy could be easily removed up until 15 cycles.