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Abstract: Superparamagnetic ascorbic acid-coated Fe3O4 nanoparticles with a high specific surface area were successfully synthesized via an environmentally friendly hydrothermal route in the absence of any templates. The as-synthesized ascorbic acid-coated Fe3O4 nanoparticles have a diameter of less than 10nm, thus leading to a high specific surface area of about 179m2/g, which is even larger than those of well-defined mesoporous structures. The only used capped agent is ascorbic acid, which serves as a functionalized molecule to make sure the high dispersibility and stability of the ascorbic acid-coated Fe3O4 nanoparticles in aqueous solution. The ascorbic acid-coated Fe3O4 nanoparticles exhibit superparamagnetic properties at room temperature and saturation magnetization approaches 40emug−1. The ascorbic acid-coated Fe3O4 nanoparticles were evaluated as an absorbent to remove heavy metal arsenic from wastewater. The adsorption data obeyed the Langmuir equation with a maximum adsorption capacity of 16.56mg/g for arsenic (V), and 46.06mg/g for arsenic (III). [Copyright &y& Elsevier]

A new model selection criterion, termed as the "quasi-likelihood under the independence model criterion" (QIC), was proposed by Pan (2001) for GEE models. Cui (2007) developed a general computing program to implement the QIC method for a range of statistical distributions. However, only a special case of the negative binomial distribution was considered in Cui (2007), where the dispersion parameter equals to unity. This article introduces a new computing program that can be applied for the general negative binomial model, where the dispersion parameter can be any fixed value. An example is also given in this article. [ABSTRACT FROM AUTHOR]

Abstract: Si3N4–SiCN composite ceramics were successfully fabricated through precursor infiltration pyrolysis (PIP) method using polysilazane as precursor and porous Si3N4 as preform. After annealed at temperatures varying from 900°C to 1400°C, the phase composition of SiCN ceramics, electrical conductivity and dielectric properties of Si3N4–SiCN composite ceramics over the frequency range of 8.2–12.4GHz (X-band) were investigated. With the increase of annealing temperature, the content of amorphous SiCN decreases and that of N-doped SiC nano-crystals increases, which leads to the increase of electrical conductivity. After annealed at 1400°C, the average real and imaginary permittivities of Si3N4–SiCN composite ceramics are increased from 3.7 and 4.68×10−3 to 8.9 and 1.8, respectively. The permittivities of Si3N4–SiCN composite ceramics show a typical ternary polarization relaxation, which are ascribed to the electric dipole and grain boundary relaxation of N-doped SiC nano-crystals, and dielectric polarization relaxation of the in situ formed graphite. The Si3N4–SiCN composite ceramics exhibit a promising prospect as microwave absorbing materials. [Copyright &y& Elsevier]

The mechanical and electromagnetic (EM) properties of Si3N4 ceramic were improved by infiltrating SiC into porous Si3N4 ceramic by chemical vapor infiltration (CVI). After CVI of SiC, the Si3N4–SiC ceramic possesses improved mechanical properties, high permittivity and dielectric loss, and excellent EM shielding effectiveness and EM absorbing properties compared to Si3N4 ceramic. The lowest EM reflection loss appears when the thickness of the Si3N4–SiC ceramic equals a quarter-wavelength, and the reflection loss remains unchanged for larger thicknesses. [Copyright &y& Elsevier]

Objective: To carry out prenatal screening and diagnosis for a woman with advanced maternal age., Methods: Non-invasive prenatal testing (NIPT) was carried out to determine the risk of fetal chromosome aneuploidy. Aminiocentesis was proceeded for fetal chromosomal karyotyping and copy number variation sequencing (CNV-seq). The fetus was subjected to systematic ultrasound screening in the second trimester., Results: NIPT has indicated there was a loss of fetal sex chromosome. Karotyping of the amniocyte showed a mosaic sex chromosome abnormality 45,X[53]/46,X,+mar[7]. The result of fetal DNA CNV-seq was seq[GRCh37]del(Yq11.1q12) chrY: g.13 104 553-28 819 361del, seq[GRCh37]del(Yp11.32p11.2) chrY: g.10 001-9 873 915del (mosaic ratio: 30%). Ultrasonography discovered that the fetus had renal dysplasia and male external genitalia. The karyotypes of the couple were both normal., Conclusion: Multiple genetic tests should be carried out for fetus with a high risk for chromosome aneuploidies signaled by NIPT. It is difficult to predict the post-natal phenotype for fetuses with mosaic sex chromosomal aneuploidies. The couple should be carefully counseled upon genetic counseling.

Objective: To delineate the nature and origin of chromosomal copy number variants (CNVs) in a boy with mental retardation and multiple congenital malformation., Methods: The karyotypes of the patient and his parents were analyzed with routine G-banded chromosomal analysis. Genome DNA was analyzed by next generation sequencing (NGS)., Results: The patient was found to harbor a structural aberration involving chromosome 3p. The karyotype of his father was 46,XY,t(3;7)(p26;q31), while his mother was found to be normal. NGS analysis of the patient revealed a 2.16 Mb microdeletion at 3p26.3-pter and a duplication at 7q31.33-qter., Conclusion: The structural aberration of 3p carried by the patient has derived from his father whom carried a balanced translocation of t(3;7), and his karyotype was finally determined as 46,XY,der(3) t(3;7)(p26.3;q31.33)pat. The abnormal phenotype of the patient can probably be attributed to the presence of 3p26.3-pter microdeletion and 7q31.33-qter duplication.