Improving Sensitivity of a Micro Inductive Sensor for Wear Debris Detection with Magnetic Powder Surrounded.

The inductive detection of wear debris in lubrication oil is an effective method to monitor the machine status. As the wear debris is usually micro scale, a micro inductive sensor is always used to detect them in research papers or high-tech products. However, the improvement of detection sensitivity for micro inductive sensors is still a great challenge, especially for early wear debris of 20 µm or smaller diameter. This paper proposes a novel method to improve the detection sensitivity of a micro inductive sensor. Regarding the magnetic powder surrounding the sensor, the magnetic field in the core of the sensor where the wear debris pass through would be enhanced due to the increased relative permeability. Thus, the inductive signal would be improved and the detection sensitivity would be increased. It is found that the inductive signal would linearly increase with increasing the concentration of the magnetic powder and this enhancement would also be effective for wear debris of different sizes. In addition, the detection limit of the micro inductive sensor used in our experiment could be extended to 11 µm wear debris by the proposed method.

Establishment of immortalized Schwann cells derived from rat embryo dorsal root ganglia.

Schwann cells (SCs) play an important role in the development, function and regeneration of peripheral nerves. They can enhance both peripheral and central nerve regeneration by providing a supportive environment for neurite outgrowth through the release of neurotrophic factors. However, use of primary SCs for in vitro models is limited because these cells are difficult to prepare and maintain in high yield and purity under common cell culture conditions. Human telomerase reverse transcriptase (hTERT) expression induces immortalization of various cell types without substantial alterations of their phenotypes. Therefore, in this study we transfected SCs with hTERT to establish a reliable cell source and observed the effect of hTERT on SCs. In order to accomplish this, SCs were isolated from rat embryo dorsal root ganglions, transfected with hTERT at early passage (passage 3). SCs passage 4, 8, 12 and 30 after transfection (hTERT-SCs) were used for immunocytochemistry, RT-PCR and western blotting. Results showed that all the early (passage 4) and late (passage 30) passage hTERT-SCs expressed hTERT mRNA and gained full telomerase activity. The transfection did not alter the mRNA expression of senescence-associated genes, such as p53 and p16. The expression of BDNF (brain-derived neurotrophic factor) was significantly decreased as cell passage increased, compared to the untransfected control. On the other hand, the expression of NGF (nerve growth factor ) was elevated at early passages (passages 4 and 8) and decreased at late passages (12 and 30). These data indicate that the use of specific immortalization techniques can establish SC lines that retain characteristics of typical primary SCs, and different mechanisms responsible for regulating NGF and BDNF expression. This is the first report regarding the immortalization of SCs derived from rat embryo dorsal root ganglions. These cells are useful in studies investigating the cellular mechanisms and regenerative processes of SCs.

TAP1 and TAP2 polymorphisms associated with ankylosing spondylitis in genetically homogenous Chinese Han population.

Human leukocyte antigen (HLA)-B27 is strongly associated with the autoimmune disease ankylosing spondylitis (AS). Other autoimmune disease-associated genes, such as transporter associated with antigen processing (TAP) genes, could also influence AS susceptibility. In this study, we investigated the association of TAP1 and TAP2 polymorphisms in genetically homogenous Chinese AS patients. Six TAP1 single nucleotide polymorphisms (SNPs) and three TAP2 SNPs sites were analyzed in B27-positive AS cases, healthy B27-negative controls, and healthy B27-positive controls. In the allele and genotype analysis, the results indicated that TAP1 site 1910 allele G, genotype AG and TAP2 site 1693 genotype AA were associated with increased AS risk in a case-B27 negative control (p < 0.05). In the haplotype analysis, TAP1 SNP haplotype (GGGGGG, TAP1*020101) and TAP1-TAP2 SNP haplotypes (GGGGGG-GGG, TAP1*020101-TAP2*0101, and GGAAGG-GAG, TAP1*0101-TAP2*0102) increased AS risk in case-B27 negative control (p < 0.05). In contrast, TAP1-TAP2 SNP haplotype GGGGGG-GAG (TAP1*020101-TAP2*0102) was less common in cases than in B27-negative controls (p < 0.05). Moreover, TAP1-TAP2 SNP haplotype GGGAGG-GGG (TAP1*0301-TAP2*0101) was less common in cases than in B27-positive controls. The two haplotypes appeared to confer protection in AS (p < 0.05). These results suggest a potential mechanism of altered antigen-peptide selection and transport in AS pathogenesis.

[Distribution of tap1 and tap2 loci allelic and genotypic frequencies in Chinese Hans].

This study was aimed to investigate the distribution and implication of tap1 (transporter associated with antigen processing) and tap2 loci allelic and genotypic frequencies. The distribution of tap1 and tap2 loci allelic and genotypic frequencies in 339 random samples of healthy Chinese Hans was analyzed by TaqMan PCR. Several genetic information about power of discrimination, cumulative DP, polymorphism information content, expected heterozygosity and observed heterozygosity were calculated. The results indicated that 5 tap1 alleles (tap1*0101, 020101, 020102, 0301 and 0401) and 4 tap2 alleles (tap2*0101, 0102, 0103 and 0201) were detected in all samples. 8 tap1 genotypes were found which account for 53.3% of the theoretic genotype and 6 tap2 genotypes were found which account for 60% of the theoretic genotype. The genotyping results of tap1 and tap2 both conform to the Hardy-Weinberg expectations (p > 0.05). Tap1*0101 (79.79%) and tap2*0101 (82.74%) are the most common alleles in Chinese Hans. It is concluded that tap1*0101 and tap2*0101 are most common alleles in Chinese Hans, tap1 and tap2 loci carry some power of individual discrimination and polymorphism information content. These two locl can be used for the research in the fields of human genetics, linkage analysis of genetic disease genes, paternity test and individual identification and so on.

[Estimating genetic distance and phylogenetic tree of HPA-1-3, 5, and 15 in different populations].

According to the human platelet alloantigens (HPA) polymorphisms in five systems, the distributions of HPA-1 -3, 5, and 15 systems in 1 000 Chinese donors were carried out by using a polymerase chain reaction with sequence-specific primers (PCR-SSP) method. The genetic distance and phylogenetic tree between Chinese Hans and other populations were estimated by using DISPAN and PHYLIP software. As presented by the phylogenetic tree, Asian had a convergence with European first, and grouped together with African. Beninese which came from Africa was on the top of dendrogram. Indian was located between Asian and European. Brazilian was converged with other Europe populations. Oceanian Polynexiya had been shown specifically to cluster with Asia populations. These results proved the "out of Africa theory" from one side, and it also confirmed that early migration of Asian is from south to southeast, and east Asia., thus it is probable that Europeans are migrated from south to north, and west Europe. As genetic distance was estimated effectively by HPA systems, HPA systems could serve as the genetic marker in human migration and evolution research.

Molecular genetic analysis for the B subgroup revealing two novel alleles in the ABO gene.

BACKGROUND: B(x) is a very rare ABO blood group phenotype and the molecular mechanism underlying it still remains largely unknown. This study reports two novel B(x) alleles in two Chinese individuals. STUDY DESIGN AND METHODS: Serologic investigations including serum transferase activity assay were performed with standard methods. DNA sequences of all seven exons and exon-intron boundaries of ABO gene were analyzed using genomic DNA by polymerase chain reaction and direct DNA sequencing or sequencing after gene cloning. RESULTS: B(x) phenotypes were diagnosed in these two individuals. DNA analysis revealed that the ABO gene of the two B(x) individuals was heterozygous of O01/B alleles. Two novel heterozygous mutations 905A>G and 541T>C were identified, respectively, which resulted in the amino acid changes D302G and W181R in the B glycosyltransferases. The mutations were not found in 120 randomly selected samples. CONCLUSION: Amino acid substitutions resulted from novel mutations 905A>G and 541T>C on ABO gene change highly conserved regions of the enzyme and may reduce the activity of the glycosyltransferases, leading to the B(x) phenotype.

HLA-A, -B, -DR haplotype frequencies from DNA typing data of 26,266 Chinese bone marrow donors.

HLA phenotypes of 26,266 Chinese individuals who were recruited as potential hematopoietic stem cell donors by the Shanghai Red Cross Marrow Donor Registry, part of the China Marrow Donor Program, were determined for HLA-A, -B, and -DRB1 alleles at low to intermediate resolution using DNA-based typing methods. The large sample size of the study allowed accurate calculation of the Chinese HLA haplotype frequencies. The observed alleles correspond to 19 HLA-A, 44 -B, and 13 -DR split antigens. The serologic equivalents of HLA-A36, -A80, -B78, and -DR18 alleles were not observed. A total of 2,241 distinct HLA-A, -B, -DRB1 haplotypes were identified. Three-locus haplotype frequency was estimated using the maximum likelihood method. The lowest haplotype frequency that can be reliably estimated at a 95% confidence level was 0.000057. Using this cutoff value, 1,220 haplotypes (54%) were statistically reliable and their cumulative haplotype frequency was 0.9730. The cumulative haplotype frequency of the remaining 1,021 haplotypes (46%) was 0.0270. A regression equation of p = 0.192 log N - 0.576 was derived to estimate the probability (p) of finding an HLA-A, -B, -DR split antigens-matched donor in a pool of N Chinese donors.

[Polymorphism of the human platelet alloantigens HPA-3 and HPA-9w in the Chinese Han population].

OBJECTIVE: To study the polymorphism of human platelet alloantigens HPA-3 and HPA-9w in the Chinese Han population. METHODS: A total of 1000 unrelated Chinese Han blood donors from different provinces of China were genotyped for HPA-3 and HPA-9w using PCR-sequence specific primer assay. RESULTS: Gene frequencies of 1000 Chinese Hans for HPA-3a and HPA-3b were 0.5935 and 0.4065 respectively, and all of them were HPA-9a positive. The distributions of HPA-3, HPA-9w of Chinese Hans which detected by chi-square criterion fit Hardy-Weinberg equilibrium. There were significant differences of the HPA-3 alleles gene frequency between Guangdong province and other five investigated provinces which included Shanxi, Heilongjiang, Zhejiang, Yunnan and Jiangsu. In comparison to other ethnic groups, no significant differences were observed in the distributions of HPA-3 except the Vietnamese and Australian. CONCLUSION: The results show that the chance of HPA-3 incompatibility were 0.3661 in random transfusion, and also provide a basis for researching on alloimmune thrombocytopenia and HPA-matched transfusion.

[Case report of a rare platelet-specific antigen HPA-10bw allele found in Chinese mainland].

A total of 1,000 Chinese blood donors were typed for human platelet antigens (HPA) using a sequence specific primers -polymerase chain reaction (PCR-SSP) based HPA genotyping method. An individual with a rare HPA-10w(a+b+) genotype was found. In order to confirm the typing results, a fragment of HPA-10 gene was amplified by PCR and then sequenced. Sequencing data showed that a single G to A substitution at nucleotide 263 occurred, resulting in amino acid change from Arg(CGA) to Gln(CAA) at position 62 of GPa protein. The substitution generated antigenic specificity HPA-10bw. The detection of an HPA-10bw allele in the Chinese population suggests that this rare allele should be considered in platelet alloimmunization, such as neonatal alloimmune thrombocytopenia (NAIT), post-transfusion thrombocytopenic purpura (PTP) and post-transfusion refractoriness to platelets (PTR).

[Advances in the studies on human platelet alloantigen--review].

Human platelet alloantigens (HPA) are specific antigens carried by platelet glycoproteins, which genes showing single nucleotide polymorphism. HPA can induce alloantibodies bringing about alloimmune response. They play important roles in post-transfusion refractoriness to platelets, post-transfusion thrombocytopenic purpura, fetomaternal alloimmune thrombocytopenia, and graft-versus-host disease. Because of their side effects in clinical blood-transfusion, there were a great deal of studies on HPA during last few decades. This review focuses on the nomenclature of HPA, the polymorphisms of platelet glycoproteins, HPA typing of the serological and molecular technology, as well as the mechanism of alloimmunization to HPA and correlated diseases.

[Molecular study on CisAB and B(A) blood group in Chinese individuals].

OBJECTIVE: This is a study on some ABO subgroup samples which show discordant results of serological and molecular blood typing, the aim is to clarify their true ABO type by means of nucleotide analysis on exons 6 and 7 of their ABO gene. METHODS: Absorb-elution test and family investigation were conducted to study 7 samples which were involved in ABO grouping discrepancies. Duplex polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) method was used to identify their ABO genotypes. PCR products of exons 6 and 7 were cloned and sequenced. RESULTS: All the 7 ABO subgroup samples with the discordant results of serological and molecular blood typing were found to have the normal O gene. Four out of them were typed as ABsub by serology, they were all of the A*102/O genotype. Sequencing analysis found all their A gene having the nt467 (C-->T) and nt803 (G-->C) mutation by comparison with the A*101 allele, i.e. their real type should be CisAB/O. Three out of 7 were typed as AsubB by serology and as BO by genotype; and point mutation was detected in all of their B gene. One of them had the nt700 (C-->G) mutation, the other 2 unrelated individuals had the novel nt640 (A-->G) mutation in their B alleles. CONCLUSION: Through nucleotide analysis, 7 samples have been typed as AB subgroup in serology with the normal O gene, their real ABO type being CisAB in 4 cases and B(A) in 3 cases. At the same time, a kind of novel B (A)640 allele has been uncovered in this study.

[IR studies on the chloride polypropylene/alkyd resin blends].

The miscibility of CPP with alkyd resin in the specified mixing ratios has been studied by FTIR spectra. The results obtained indicate that the bands of hydroxyl groups noticeably shifted in the FTIR spectra of the blends in contrast with the infrared spectrum of alkyd resin, and the blends were miscible when the weight fraction of alkyd resin in the blends of CPP and alkyd resin was less than 0.5, and immiscible when greater than 0.5, which were proved by the glossiness of their films.

Desulfurizing absorbent for flue gas and its absorption mechanism.

A new desulfurizing absorbent for flue gas, i.e., an organic physical solvent of DMSO(dimethyl sulfoxide) mixed with a relatively small amount of chemical solvent (Mn2+) was studied. Compared with pure physical solvent of DMSO, the purification efficiency of the new absorbent was improved. And its absorption and reaction mechanism are discussed.