ABSTRACT
Objective:To determine the disinfection effect in child care institutions in Qingpu District of Shanghai， and provide evidence for improving the disinfection quality and preventing and controlling infectious diseases. Methods:According to the monitoring program of disinfection quality in child care institutions in Shanghai， disinfection quality was monitored for 3 years. Results:A total of 979 samples were monitored in the consecutive three years， in which 895 samples were qualified with a total qualification rate of 91.42%. The qualification rate of air samples was 100.00%， while the rate of staff hand samples was the lowest， with an average of 79.60%. During 2016-2018， the difference among the annual qualification rates was statistically significant（χ2=23.809，P<0.05）， whereas it was not significant in the rates between public institutions and private ones （χ2=0.141，P>0.05）. Conclusion:The quality of preventive disinfection in child care institutions in Qingpu District is generally good， but the disinfection of tableware， surface of objects and staff needs to be further improved.
ABSTRACT
Portable low-cost magnetic resonance imaging (MRI) systems have the potential to enable “point-of-care” and timely MRI diagnosis, and to make this imaging modality available to routine scans and to people in underdeveloped countries and areas. With simplicity, no maintenance, no power consumption, and low cost, permanent magnets/magnet arrays/magnet assemblies are attractive to be used as a source of static magnetic field to realize the portability and to lower the cost for an MRI scanner. However, when taking the canonical Fourier imaging approach and using linear gradient fields, homogeneous fields are required in a scanner, resulting in the facts that either a bulky magnet/magnet array is needed, or the imaging volume is too small to image an organ if the magnet/magnet array is scaled down to a portable size. Recently, with the progress on image reconstruction based on non-linear gradient field, static field patterns without spatial linearity can be used as spatial encoding magnetic fields (SEMs) to encode MRI signals for imaging. As a result, the requirements for the homogeneity of the static field can be relaxed, which allows permanent magnets/magnet arrays with reduced sizes, reduced weight to image a bigger volume covering organs such as a head. It offers opportunities of constructing a truly portable low-cost MRI scanner. For this exciting potential application, permanent magnets/magnet arrays have attracted increased attention recently. A magnet/magnet array is strongly associated with the imaging volume of an MRI scanner, image reconstruction methods, and RF excitation and RF coils, etc. through field patterns and field homogeneity. This paper offers a review of permanent magnets and magnet arrays of different kinds, especially those that can be used for spatial encoding towards the development of a portable and low-cost MRI system. It is aimed to familiarize the readers with relevant knowledge, literature, and the latest updates of the development on permanent magnets and magnet arrays for MRI. Perspectives on and challenges of using a permanent magnet/magnet array to supply a patterned static magnetic field, which does not have spatial linearity nor high field homogeneity, for image reconstruction in a portable setup are discussed.
Subject(s)
Diagnosis , Head , Image Processing, Computer-Assisted , Magnetic Fields , Magnetic Resonance ImagingABSTRACT
Objective To genetically correct a disease-causing point mutation in human induced pluripotent stem cells (iPSCs) derived from a hemophilia B patient. Methods First, the disease-causing mutation was detected by sequencing the encoding area of human coagulation factor IX (F IX) gene. Genomic DNA was extracted from the iPSCs, and the primers were designed to amplify the eight exons of F IX. Next, the point mutation in those iPSCs was genetically corrected using CRISPR/Cas9 technology in the presence of a 129-nucleotide homologous repair template that contained two synonymous mutations. Then, top 8 potential off-target sites were subsequently analyzed using Sanger sequencing. Finally, the corrected clones were differentiated into hepatocyte-like cells, and the secretion of F IX was validated by immunocytochemistry and ELISA assay. Results The cell line bore a missense mutation in the 6coding exon (c.676 C>T) of F IX gene. Correction of the point mutation was achieved via CRISPR/Cas9 technology in situ with a high efficacy at about 22% (10/45) and no off-target effects detected in the corrected iPSC clones. F IX secretion, which was further visualized by immunocytochemistry and quantified by ELISA in vitro, reached about 6 ng/ml on day 21 of differentiation procedure. Conclusions Mutations in human disease-specific iPSCs could be precisely corrected by CRISPR/Cas9 technology, and corrected cells still maintained hepatic differentiation capability. Our findings might throw a light on iPSC-based personalized therapies in the clinical application, especially for hemophilia B.
ABSTRACT
Objective To analyze the stability of chromosome variant ratio of three available transformed corneal cell lines. Methods Chromosome specimens of transformed cells including human corneal epithelial cells(HCE),bovine corneal endothelial cells(BCE) and rabbit corneal epithelial cells(RCE) were prepared by a direct method using regular Giemsa staining. Chromosomes of cells in metaphase were counted under the microscope. Then, the variant ratio of chromosomes and their nuclear types were analyzed. Results The chromosome numbers were 56 to 65, 27 to 34 and 74 to 88 for HCE, BCE and RCE, respectively. Chromosome numbers in the three commonly used and transformed corneal cell lines were changed in comparison to their parent tissues. Conclusion Genotyping study may provide important information for using HCE、BCE、RCE in functional studies.