Mechanism of the interaction between Au nanoparticles and polymerase in nanoparticle PCR

Nanoparticle PCR is a novel method to optimize DNA amplification. It performs well in improving specificity, enhancing sensitivity and speed. Several mechanisms were proposed in previous studies: one was based on the interaction between gold nanoparticles (AuNPs) and DNA while the other was attributed to the heat transfer property of AuNPs. In this paper, we propose that the interaction between AuNPs and DNA polymerase can significantly influence PCR. First, the addition of DNA polymerase can eliminate the inhibitory effects of excess AuNPs. Second, the addition of AuNPs will increase yield of the desired PCR product and make the optimum concentration of DNA polymerase move to higher value. Third, while excess polymerase might inhibit amplification efficiency, AuNPs can reverse this process and the yield of PCR amplification. Based on these results we propose a possible mechanism that AuNPs might modulate the activity of polymerase and improve PCR amplification.     

Home risk factors for childhood pneumonia in Nanjing, China

Pneumonia is a major cause of childhood morbidity in China. Many studies of rural areas have found an association between pneumonia and air pollution from burning of bio-mass. The present study is of children living in urban, modern homes without burning of bio-mass. In order to investigate potential home risk factors associated with children’s pneumonia, China Child Home Health (CCHH) questionnaires were randomly distributed to parents of 6461 children in 23 kindergartens in all 11 districts of Nanjing, covering urban, suburban, and industrial areas. The 4014 valid questionnaires (response rate 65.7%) were returned and have been analyzed. The lifetime incidence of pneumonia in Nanjing children 1–8 years old is 26.7%. The incidence of croup, asthma and frequent common colds was strongly associated with pneumonia, as was a history of allergies in the family, and persons other than parents (for example grandparents or nanny) taking care of the child. Several home environmental factors, namely, dampness, lack of ventilation, using coal or natural gas (electricity as reference) for cooking, new furniture, and “modern” floor and wall covering materials were also significantly associated with pneumonia. The indoor environment typical of modern apartments in China was a risk factor for pneumonia among children.     

Preparation and characterization of 3-aminopropyltriethoxysilane grafted montmorillonite and acid-activated montmorillonite

3-aminopropyltriethoxysilane grafted montmorillonites were synthesized with montmorillonite, acidactivated montmorillonites and 3-aminopropyltriethoxysilane in ethanol-water mixture. The resulting products were investigated using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TG). XRD patterns demonstrated that silane was intercalated into the montmorillonite gallery, indicated by increasing basal spacings. These intercalated silanes probably adopt bilay...     

Synthesis, characterization and size control of zerovalent iron nanoparticles anchored on montmorillonite

Zerovalent iron nanoparticles have been successfully synthesized using sodium borohydride solution reduction of ferric trichloride hexahydrate in the presence of montmorillonite as an effective protective reagent and support as well. A combination of characterizations reveals that with high monodispersity these obtained iron nanoparticles are well dispersed on clay surface, virginal from boron related impurity, and oxidation resistant well with iron core-iron oxide shell structure. The shell thickness of 3 ...     

Abnormal gonad development in Kit W-2Bao mice caused by a Kit gene missense mutation

Kit ^W-2Bao mice are single-gene autosomal dominant mutation mice with a B6 background that were bred in our laboratory. Heterozygotes had morphological characteristics including albinism of the abdomen, extremities, and tail, whereas the homozygotes had albinism of the body, black eyes, and infertility. The homozygous mutants showed small, structurally abnormal gonads, and lacked germ cells. Heterozygous male mice lacked germ cells in some contorted seminiferous tubules. This mutation has been mapped at 43.8 cM from the centromere in chromosome 5 by linkage analysis and Kit has been identified as the candidate gene. After Kit full-length mRNA amplification, it was found that a G to T conversion at position 1228 in the ORF changed the 410th amino acid from V to F. This amino acid change could affect the protein’s secondary structure. Heterozygous mutant mice were intercrossed and homozygous mutant mice were bred and genotyped. We found that no primordial germ cells (PGCs) appeared in the urogenital ridge area at fetus day 11.5 in the homozygotes. The number of PGCs also significantly decreased in heterozygotes. At fetus day 15.5, the differentiation of the testis tubule structure was unclear; as well, they contained no spermatogonia. Female homozygotes contained no primordial follicles in the ovary. The numbers of PGCs and primordial follicles were significantly decreased in heterozygous mice. W ^?2Bao is the only mutated site in the extracellular 4th Ig-like domain and this mutant mouse model provides new material for the study of the mechanism of reproductive system development.     

微机联用的电化学渗氢测量系统

设计?电化?氢测量系统,可用于?氢的时滞法测定和频率响应法测定,通过简单的D/A转换时控制电路同AppleⅡ微机联接,实现了自动化的测量控制,数据采集相数据处理,该系统改善了测量精度,??了工作效率。     

Review on development of volumetric particle image velocimetry

Volumetric particle image velocimetry （PIV） is a laser technique measuring three-component velocity field in a volume. Common volumetric PIV techniques are defocusing PIV, multi-view PIV and holographic PIV. Tomographic PIV is an advanced approach of multi-view PIV, which significantly improves the spatial resolution of the measurement by using the multiplicative algebraic reconstruction technique （MART） to reconstruct the particle field. Due to the rapid progress being made in volumetric PIV meas- urements, this article focuses on introducing the principles of different volumetric PIV methods from aspects of particle recon- struction and velocity reconstruction. Advantages and limitations on applications are elaborated. Issues specific to volumetric PIV regarding illumination, digital imaging, depth of focus, ghost particle and spatial resolution are discussed.