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Design of a Bandgap Reference with a Wide Supply Voltage Range 被引量:4
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作者 孙越明 赵梦恋 吴晓波 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第8期1529-1534,共6页
An on-chip voltage reference with a wide supply voltage range is required by some applications,especially that of power management (PM) controller chips applied to telecommunication, automotive, lighting equipment, ... An on-chip voltage reference with a wide supply voltage range is required by some applications,especially that of power management (PM) controller chips applied to telecommunication, automotive, lighting equipment, etc., when high power supply voltage is needed. Accordingly,a new bandgap reference with a wide supply voltage range is proposed. Due to the improved structure,it features a high power supply rejection ratio (PSRR) and high temperature stability. In addition, an auxiliary micro-power reference is introduced to support the sleep mode of the PM chip and reduce its standby power consumption. The auxiliary reference provides bias currents in normal mode and a 1.28V reference voltage in sleep mode to replace the main reference and save power. Simulation results show that the reference provides a reference volt- age of 1.27V,which has a 3.5mV drift over the temperature range from -20 to 120~C and 56t^V deviation over a supply voltage range from 3 to 40V. The PSRR is higher than 100dB for frequency below 10kHz. The circuit was completed in 1.5tzm BCD (Bipolar-CMOS-DMOS) technology. The experimental results show that all main expectations are achieved. 展开更多
关键词 wide supply voltage range bandgap reference line regulation sleep mode micro power
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Dynamic regulation of alternative splicing and chromatin structure in Drosophila gonads revealed by RNA-seq 被引量:11
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作者 Qiang Gan Iouri Chepelev +4 位作者 Gang Wei Lama Tarayrah Kairong Cui Keji Zhao Xin Chen 《Cell Research》 SCIE CAS CSCD 2010年第7期763-783,共21页
Both transcription and post-transcriptional processes, such as alternative splicing, play crucial roles in controlling developmental programs in metazoans. Recently emerged RNA-seq method has brought our understanding... Both transcription and post-transcriptional processes, such as alternative splicing, play crucial roles in controlling developmental programs in metazoans. Recently emerged RNA-seq method has brought our understanding of eukaryotic transcriptomes to a new level, because it can resolve both gene expression level and alternative splicing events simultaneously. To gain a better understanding of cellular differentiation in gonads, we analyzed mRNA profiles from Drosophila testes and ovaries using RNA-seq. We identified a set of genes that have sex-specific isoforms in wild-type (WT) gonads, including several transcription factors. We found that differentiation of sperms from undifferentiated germ cells induced a dramatic downregulation of RNA splicing factors. Our data confirmed that RNA splicing events are significantly more frequent in the undifferentiated cell-enriched bag of marbles (barn) mutant testis, but downregulated upon differentiation in WT testis. Consistent with this, we showed that genes required for meiosis and terminal differentiation in WT testis were mainly regulated at the transcriptional level, but not by alternative splicing. Unexpectedly, we observed an increase in expression of all families of chromatin remodeling factors and histone modifying enzymes in the undifferentiated cell-enriched bam testis. More interestingly, chromatin regulators and histone modifying enzymes with opposite enzymatic activities are coenriched in undifferentiated cells in testis, suggesting that these cells may possess dynamic chromatin architecture. Finally, our data revealed many new features of the Drosophila gonadal transcriptomes, and will lead to a more comprehensive understanding of how differential gene expression and splicing regulate gametogenesis in Drosophila. Our data provided a foundation for the systematic study of gene expression and alternative splicing in many interesting areas of germ cell biology in Droso- phila, such as the molecular basis for sexual dimorphism and the regulation of the proliferation vs terminal differentiation programs in germline stem cell lineages. The GEO accession number for the raw and analyzed RNA-seq data is GSE16960. 展开更多
关键词 TRANSCRIPTION alternative splicing differentiation TESTIS OVARY DROSOPHILA
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Diester Derivatives from Chemically Modified Waste Cooking Oil as Substitute for Petroleum Based Lubricating Oils 被引量:1
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作者 Xiang Shuo Chen Ligong +3 位作者 Xu Lan Li Liang Yang Xin Zhu Liye 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2015年第2期76-83,共8页
In order to provide a new way for waste cooking oil(WCO) resource utilization, several diester derivatives were obtained from WCO through a three-step chemical modifications, viz.: transesterification, epoxidation and... In order to provide a new way for waste cooking oil(WCO) resource utilization, several diester derivatives were obtained from WCO through a three-step chemical modifications, viz.: transesterification, epoxidation and oxirane ring opening with carboxylic acids. The effects of the chain length of side chain groups on the viscosity, acid value, low temperature fluidity, thermo-oxidative stability, tribological properties and surface tension of diester derivatives were investigated. The results showed that increasing the chain length of side chain groups had a positive influence on the viscosity, viscosity index, acid value, pour point, friction coefficient and wear scar diameter along with a negative influence on the oxidation onset temperature, volatile loss, insoluble deposit, maximum non-seizure load and surface tension. These diester derivatives exhibited improved physicochemical and tribological properties that make themselves promising environmentally friendly biolubricant basestocks. 展开更多
关键词 waste cooking oil diester derivative lubricating oil physicochemical property tribological property
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Coordinated regulation of active and repressive histone methylations by a dual-specificity histone demethylase ceKDM7A from Caenorhabditis elegans 被引量:2
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作者 Hanqing Lin Yiqin Wang +11 位作者 Yanru Wang Feng Tian Pu Pu Yi Yu Hailei Mao Ying Yang Ping Wang Lulu Hu Yan Lin Yi Liu Yanhui Xu Charlie Degui Chen 《Cell Research》 SCIE CAS CSCD 2010年第8期899-907,共9页
H3K9me2 and H3K27me2 are important epigenetic marks associated with transcription repression, while H3K4me3 is associated with transcription activation. It has been shown that active and repressive histone methylation... H3K9me2 and H3K27me2 are important epigenetic marks associated with transcription repression, while H3K4me3 is associated with transcription activation. It has been shown that active and repressive histone methylations distribute in a mutually exclusive manner, but the underlying mechanism was poorly understood. Here we identified ceKDM7A, a PHD (plant homeodomain)- and JmjC domain-containing protein, as a histone demethylase specific for H3K9me2 and H3K27me2. We further demonstrated that the PHD domain of ceKDM7A bound H3K4me3 and H3K4me3 co-localized with ceKDM7A at the genome-wide level. Disruption of the PHD domain binding to H3K4me3 reduced the demethylase activity in vivo, and loss of ceKDM7A reduced the expression of its associated target genes. These results indicate that ceKDM7A is recruited to the promoter to demethylate H3K9me2 and H3K27me2 and activate gene expression through the binding of the PHD domain to H3K4me3. Thus, our study identifies a dual-specificity histone demethylase and provides novel insights into the regulation of histone methylation. 展开更多
关键词 KDM7A DEMETHYLASE H3K9me2 H3K27me2 PHD JMJC HISTONE methylation
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Isolation of a pollen-specific promoter in tritordeum
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作者 Tu Zhiming Zhang Jiangzhou +3 位作者 Chen Lin Chuan Qin Yang Guangxiao He Guangyuan 《Engineering Sciences》 EI 2011年第1期72-75,共4页
The promoter is a cis-acting element in regulating gene expression. A promoterless plasmid containing UidA gene was transformed into tritordeum by barmbadment. Histochemical analysis of various tissues in transgenic t... The promoter is a cis-acting element in regulating gene expression. A promoterless plasmid containing UidA gene was transformed into tritordeum by barmbadment. Histochemical analysis of various tissues in transgenic tritordeum was carried to examine tissue-specific expression of GUS(beta-glucuronidase) activity. The pollen-specific promoter was trapped and identified successfully in a transformant line. PCR(polymerase chain reaction) method was used to isolate this pollen-specific promoter. By sequencing and analyzing the amplified fragment from PCR, a part of UidA gene and a flanking sequence were obtained. Some essential elements of plant promoters were found in the sequence. To determine the function of it, the cloned fragment was fused with UidA gene, then cloned and transformed into Triticum durum. The transgenic plant transformed by this vector showed GUS expression only in pollen. Therefore a pollen-specific promoter was isolated successfully. 展开更多
关键词 tissue-specific promoter TRANSCRIPTION POLLEN transformation TRANSGENE
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Comprehensive Evaluation Model of Reservoir Operation Based on Improved Set Pair Analysis 被引量:4
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作者 任炳昱 孙宜超 +2 位作者 周正印 程正飞 胡兴富 《Transactions of Tianjin University》 EI CAS 2013年第1期25-28,共4页
A comprehensive evaluation model based on improved set pair analysis is established. Considering the complexity in decision-making process, the model combines the certainties and uncertainties in the schemes, i.e., id... A comprehensive evaluation model based on improved set pair analysis is established. Considering the complexity in decision-making process, the model combines the certainties and uncertainties in the schemes, i.e., identical degree, different degree and opposite degree. The relations among different schemes are studied, and the traditional way of solving uncertainty problem is improved. By using the gray correlation to determine the difference degree, the problem of less evaluation indexes and inapparent linear relationship is solved. The difference between the evaluation parameters is smaller in both the fuzzy comprehensive evaluation model and fuzzy matter-element method, and the dipartite degree of the evaluation result is unobvious. However, the difference between each integrated connection degree is distinct in the improved set pair analysis. Results show that the proposed method is feasible and it obtains better effects than the fuzzy comprehensive evaluation method and fuzzy matter-element method. 展开更多
关键词 set pair analysis comprehensive evaluation model gray correlation reservoir operation
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Research progress on the relationship between BRCA1 and hereditary breast cancer 被引量:2
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作者 Ping Liu Chao Wu Shengli Yang 《The Chinese-German Journal of Clinical Oncology》 CAS 2013年第12期602-606,共5页
Breast cancer gene 1(BRCA1) gene was the first breast cancel susceptibility gene discovered in familial breast cancer.It has been revealed that BRCA1 can be combined with an array of important protein involved in cell... Breast cancer gene 1(BRCA1) gene was the first breast cancel susceptibility gene discovered in familial breast cancer.It has been revealed that BRCA1 can be combined with an array of important protein involved in cell cycle regulation,DNA repair,gene transcription control and apoptosis regulation.It plays a down-regulation effect on tumor growth and an important role in maintaining genomic stability.New research suggests that it also associate with the breast cancer stem cells and microRNA.Its mutations,promoter methylation and ectopic expression may one of the main reasons for the generation and development of hereditary breast cancer. 展开更多
关键词 breast cancer gene 1 (BRCA1) breast cancer tumor suppressor gene
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Genome-wide Identification and Analysis of DNA Methyltransferases in Grape 被引量:2
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作者 Fengshan REN Liying YANG +3 位作者 Ling SU Lei GONG Pengfei WANG Yongmei WANG 《Agricultural Science & Technology》 CAS 2017年第10期1781-1787,1794,共8页
DNA methylation is an important epigenetic regulation mechanism, which is catalyzed by DNA methyltransferases. In this study, eight DNA methyltransferase genes were identified in grape genome to analyze the selective ... DNA methylation is an important epigenetic regulation mechanism, which is catalyzed by DNA methyltransferases. In this study, eight DNA methyltransferase genes were identified in grape genome to analyze the selective pressure, gene expression and codon usage bias. The results showed grape DNA methyltransferase MET subfamily underwent relatively strong purifying selection during evolution, while chromomethylase CMT subfamily underwent positive selection during evolution. Under different abiotic(heat, drought or cold) stresses, the expression level of many grape DNA methyltransferase genes changed significantly. The expression level of these genes might be related with cis-regulatory elements of their promoters. The results of codon usage bias analysis showed that synonymous codon bias existed in grape DNA methyltransferase gene family, which might be affected by mutation pressure. These results laid a solid foundation for in-depth study of DNA methyltransferases in grape. 展开更多
关键词 DNA methylation DNA methyltransferase GRAPE Selective pressure Codon usage bias
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DNA Methylation Analysis of Cassava (Manihotesculenta Crantz) SC8 and Its Autotetraploid in Response to Cold Stress 被引量:1
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作者 Xue Jing jing Li Kaimian Chen Songbi 《Journal of Food Science and Engineering》 2017年第6期297-304,共8页
DNA methylation plays a vital role in the regulation of gene expression in response to environmental stress. However, little is known about the effect of DNA methylation on the cassava polyploidy. In the present study... DNA methylation plays a vital role in the regulation of gene expression in response to environmental stress. However, little is known about the effect of DNA methylation on the cassava polyploidy. In the present study, methylation-sensitive amplified polymorphisms (MSAP) were used to investigate DNA methylation profiles of cassava polyploidy following cold treatment to identify candidate genes involved in response to cold stress. The result showed that the genome-wide DNA methylation polymorphisms accounted for 34.02%-42.56% in SC8 and its autotetraploid exposed to 5 ~C for 2, 8, 24 and 48 h, respectively. The methylation levels of SC8 at 2 h-cold stress were the highest during 48h under cold treatments. With the time extension within 48 h under cold stress, the methylation levels gradually decreased to the same level as the control but DNA methylation levels of cassava autotetraploid were stable within 48 h. For future analysis of the methylation extent, the cold stress induced more DNA methylation than demethylation in SC8, where DNA methylation was consistent with demethylation in its autotetraploid. The expression analysis demonstrated increase in the transcription of one methylated gene and decrease in the transcription of two demethylated genes. The results revealed that gene methylations in specific sites would be a rapidly epigenetic response to cold stress, further elucidating the methylation functions in its autotetraploid. 展开更多
关键词 Cassava SC8 tissue culture seedling MSAP cold stress.
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Reduction of natural regulatory T cells in thymomas accompanying myasthenia gravis and its possible association with Foxp3 and thymic stromal lymphopoietin 被引量:3
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作者 Wang Zhongkui Wang Jinghua Deng Benqiang Ding Suju Wu Tao 《Journal of Medical Colleges of PLA(China)》 CAS 2009年第1期50-55,共6页
Objective: To investigate the expression of both thymic regulatory T cells (CD4+CD25+Foxp3+cells, Treg) and thymic stromal lymphopoietin (TSLP) in thymomas accompanying myasthenia gravis. Methods: We used immunohistoc... Objective: To investigate the expression of both thymic regulatory T cells (CD4+CD25+Foxp3+cells, Treg) and thymic stromal lymphopoietin (TSLP) in thymomas accompanying myasthenia gravis. Methods: We used immunohistochemistry and real-time reverse trancription polymerase chain reaction (real-time RT-PCR) techniques to determine Foxp3+ Treg counts and the expression levels of Foxp3 mRNA and TSLP mRNA in thymomas of 23 MG patients and thymuses of 4 healthy controls. Results: The CD4+ Foxp3+ nTreg (natural regulatory T cells) counts in thymomas were significantly lower than those in normal thymuses (P<0.01), and the expression levels of Foxp3 mRNA and TSLP mRNA were also lower in thymomas(P<0.01). Among the thymoma types, type B1 thymoma had the highest Foxp3+ nTreg count and standard values of Foxp3 mRNA and TSLP mRNA. There was a strong positive correlation between the mRNA transcriptional levels of Foxp3 and TSLP. Conclusion: The insufficient expression of Foxp3 in thymoma, which may be caused by decreased transcription of TSLP, may result in the reduction of Tregs and cause autoimmune disorders. 展开更多
关键词 Myasthenia gravis THYMOMA Regulatory T cell FOXP3 Thymic stromal lymphopoietin
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Analysis of Synonymous Codon Usage Bias in 09H1N1 被引量:3
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作者 Zhen-peng LI De-quan YING Peng LI Fei LI Xiao-chen BO Sheng-qi WANG 《Virologica Sinica》 SCIE CAS CSCD 2010年第5期329-340,共12页
A novel subtype of influenza A virus 09H1N1 has rapidly spread across the world. Evolutionary analyses of this virus have revealed that 09H1N1 is a triple reassortant of segments from swine, avian and human influenza ... A novel subtype of influenza A virus 09H1N1 has rapidly spread across the world. Evolutionary analyses of this virus have revealed that 09H1N1 is a triple reassortant of segments from swine, avian and human influenza viruses. In this study, we investigated factors shaping the codon usage bias of 09H1N1 and carried out cluster analysis of 60 strains of influenza A virus from different subtypes based on their codon usage bias. We discovered that more preferentially used codons of 09H1N1 are A-ended or U-ended, and the intra-genomic codon usage bias of 09H1N1 is quite low. Base composition constraint, dinucleotide biases and translational selection are the main factors influencing the codon usage bias of 09H1N1. At the genome level, we find that the codon usage bias of 09H1N1 is similar to H1N1 (A/swine/Kansas/77778/2007H1N1), H9N2 from Asia, H1N2 from Asia and North America and H3N2 from North America. Our results provide insight for understanding the processes governing evolution, regulation of gene expression, and revealing the evolution of 09H1N1. 展开更多
关键词 09H1N1 Correspondence analysis Codon usage bias
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A new polymorphism in the GRP78 is not associated with HBV invasion
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作者 Xiao Zhu Yi Wang +5 位作者 Tao Tao Dong-Pei Li Fei-Fei Lan Wei Zhu Dan Xie Hsiang-Fu Kung 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第39期4958-4961,共4页
AIM:To examine the association between -86 bp(T>A) in the glucose-regulated protein 78 gene(GRP78) and hepatitis B virus(HBV) invasion.METHODS:DNA was genotyped for the single-nucleotide polymorphism by polymerase ... AIM:To examine the association between -86 bp(T>A) in the glucose-regulated protein 78 gene(GRP78) and hepatitis B virus(HBV) invasion.METHODS:DNA was genotyped for the single-nucleotide polymorphism by polymerase chain reaction followed by sequencing in a sample of 382 unrelated HBV carriers and a total of 350 sex-and age-matched healthy controls.Serological markers for HBV infection were determined by enzyme-linked immunosorbent as-say kits or clinical chemistry testing.RESULTS:The distributions of allelotype and genotype in cases were not significantly different from those in controls.In addition,our fi ndings suggested that neither alanine aminotransferase/hepatitis B e antigen nor HBV-DNA were associated with the allele/genotype variation in HBV infected individuals.CONCLUSION:-86 bp T>A polymorphism in GRP78 gene is not related to the clinical risk and acute exacerbation of HBV invasion. 展开更多
关键词 Acute exacerbation Glucose-regulated protein 78 Hepatitis B virus Single-nucleotide polymorphism
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Characterization of the Xenopus homolog of animmediate early gene associated with cell activation: sequence analysis and regulation of its expression by thyroid hormone during amphibian metamorphosis
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作者 VIVIACTLIANG TIFFANYSEDGWICK 《Cell Research》 SCIE CAS CSCD 1997年第2期179-193,共15页
The complex transformation of a tadpole to a frogduring amphibian development is under the control of thyroid hormone (T3). T3 is known to regulate gene transcription through its nuclear receptors. We have previouslyi... The complex transformation of a tadpole to a frogduring amphibian development is under the control of thyroid hormone (T3). T3 is known to regulate gene transcription through its nuclear receptors. We have previouslyisolated many genes which are up-regulated by T3 in theintestine of Xenopus laevis tadpoles. We have now cloneda full- length cDNA for one such gene (IU12). Sequenceanalysis shows that the IU12 cDNA encodes a plasmamembrane protein with 12 transmembrane domains andhomologous to a mammalian gene associated with cell activation and organ development. Similarly, we have foundthat IU12 is activated during intestinal remodeling whenboth cell death and proliferation take place. Furthermore,IU12 is an early T3-response gene and its expression in theintestine during T3-induced metamorphosis mimics thatduring normal development. These results argue for a roleof IU12 in the signal transduction pathways leading to intestinal metamorphosis. 展开更多
关键词 Thyroid hormone Xenopus laevis cell proliferation ORGANOGENESIS transcription factor
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Total Phenolic Content and Antioxidative Activity in Seasoning Protein Hydrolysate as Affected by Pasteurization and Storage
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作者 K. Arunrat S. Siripongvutikom C. Thongraung 《Journal of Food Science and Engineering》 2011年第4期252-262,共11页
Protein hydrolysate prepared from fish and shrimp by-products were used to prepare a seasoning protein hydrolysate (SPH). The effects of pasteurization and storage on total phenolic content (TPC), DPPH radical sca... Protein hydrolysate prepared from fish and shrimp by-products were used to prepare a seasoning protein hydrolysate (SPH). The effects of pasteurization and storage on total phenolic content (TPC), DPPH radical scavenging activity, reducing power, and color of the SPH were investigated. Pasteurization at 90 ℃ for 10 minutes led to a reduction of TPC and DPPH radical scavenging activity and an increase of reducing power of solid fraction of SPH by about 30%, 99%, and 100%, respectively. Consequently it increased TPC DPPH radical scavenging activity, and reducing power of the liquid phase by about 32%, 600%, and 100%, respectively. Storage at 28, 35, or 45 ℃ for 12 weeks altered color values and increased brownness intensity (OD420). The storage led to an apparent increase of the TPC and antioxidative activity of the product. The results indicate the possibility of producing healthy appetizers from protein hydrolysate prepared from by-products of the seafood industry. 展开更多
关键词 Seasoning protein hydrolysate PASTEURIZATION DPPH storage and antioxidative activity.
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Adeno-associated virus mediated delivery of Tregitope 167 ameliorates experimental colitis
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作者 Sander van der Marel Anna Majowicz +8 位作者 Karin Kwikkers Richard van Logtenstein Anje A te Velde Anne S De Groot Sybren L Meijer Sander J van Deventer Harald Petry Daniel W Hommes Valerie Ferreira 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第32期4288-4299,共12页
AIM:To explore the anti-inflammatory potential of adeno-associated virus-mediated delivery of Tregitope 167 in an experimental colitis model.METHODS:The trinitrobenzene sulfonate(TNBS) model of induced colitis was use... AIM:To explore the anti-inflammatory potential of adeno-associated virus-mediated delivery of Tregitope 167 in an experimental colitis model.METHODS:The trinitrobenzene sulfonate(TNBS) model of induced colitis was used in Balb/c mice.Subsequently after intravenous adeno-associated virusmediated regulatory T-cell epitopes(Tregitope) delivery,acute colitis was initiated by intra-rectal administration of 1.5 mg TNBS in 40% ethanol followed by a second treatment with TNBS(0.75 mg in 20% ethanol) 8 d later.Control groups included mice not treated with TNBS(healthy control group) and mice treated by TNBS only(diseased group).At the time of sacrifice colon weight,the disease activity index and histology damage score were determined.Immunohistochemical staining of the colonic tissues was performed to asses the cellular infiltrate and the presence of transcription factor forkhead Box-P3(Foxp3).Thymus,mesenteric lymph nodes,liver and spleen tissue were collected and the corresponding lymphocyte populations were further assessed by flow cytometry analysis for the expression of CD4+ T cell and regulatory T cell associated markers.RESULTS:The Tregitope 167 treated mice gained an average of 4% over their initial body weight at the time of sacrifice.In contrast,the mice treated with TNBS alone(no Tregitope) developed colitis,and lost 4% of their initial body weight at the time of sacrifice(P < 0.01).The body weight increase that had been observed in the mice pre-treated with Tregitope 167 was substantiated by a lower disease activity index and a decreased colon weight as compared to the diseased control group(P < 0.01 and P < 0.001,respectively).Immunohistochemical staining of the colonic tissues for CD4+ showed that inflammatory cell infiltrates were present in TNBS treated mice with or without administration with tregitope 167 and that these cellular infiltrates consisted mainly of CD4+ cells.For both TNBS treated groups CD4+ T cell infiltrates were observed in the sub-epithelial layer and the lamina propria.CD4+ T cell infiltrates were also present in the muscularis mucosa layer of the diseased control mice,but were absent in the Tregitope 167 treated group.Numerous Foxp3 positive cells were detected in the lamina propria and sub-epithelium of the colon sections from mice treated with Tregitope 167.Furthermore,the Foxp3 and glycoprotein A repetitions predominant markers were significantly increased in the CD4+ T lymphocyte population in the thymus of the mice pre-treated with adeno-associated virus serotype 5(cytomegalovirus promoter-Tregitope 167),as cytomegalovirus promoter compared to lymphocyte populations in the thymus of diseased and the healthy control mice(P < 0.05 and P < 0.001,respectively).CONCLUSION:This study identifies adeno-associated virus-mediated delivery of regulatory T-cell epitope 167 as a novel anti-inflammatory approach with the capacity to decrease intestinal inflammation and induce longterm remission in inflammatory bowel disease. 展开更多
关键词 Adeno-associated virus Regulatory T cell epitope Inflammatory bowel diseases Adeno-associated virus
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Polymorphism in the Regulatory Region of the Aromatase CYP19a Gene in Nile Tilapia
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作者 Marilia Danyelle Nunes Rodrigues Rafael Aldrighi Tavares +5 位作者 Harold Julian Perez Gutierrez Diones Bender Almeida Carla Giovane Avila Moreira Cecilia Calabuig Josiane Bonel Raposo Heden Luiz MarquesMoreira 《Journal of Life Sciences》 2014年第2期101-105,共5页
The aim of this study was to evaluate the polymorphism in a portion of the gene regulatory region for ovarian aromatase (CYP19a) in three strains of Tilapia, Oreochomis niloticus (Linnaeus) (GIFT--Genetically Imp... The aim of this study was to evaluate the polymorphism in a portion of the gene regulatory region for ovarian aromatase (CYP19a) in three strains of Tilapia, Oreochomis niloticus (Linnaeus) (GIFT--Genetically Improved Farmed Tilapia, Chitralada and Supreme). A total of 90 animals per strain of Tilapia, Oreochromis niloticus (Linnaeus) were analysed. After DNA extraction, samples were subjected to PCR using primers designed to flank the region of interest encompassing the sites of transcription (WT1-KTS and SRY). Samples were analyzed by PCR-SSCP and subsequently sequenced. Three polymorphisms were identified in this region, resulting in two different sequences, in the GIFT strain while no polymorphism was found in both Supreme and Chitralada strains. At the position - 1178 the substitution of a guanine for a cytosine, at the - 1081 the exchange of guanine for adenine and at the position -1 138 we found a SNP, possible site of heterozygosity. Even with polymorphisms in the target study area, when taking the three strains into account, one can assume that the portion of the regulatory region of the ovarian aromatase gene in the Supreme strain and Chitralada does not show polymorphism. 展开更多
关键词 Ovarian aromatase Oreochromis niloticus POLYMORPHISM regulatory region.
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Preliminary Investigation on Somatic Embryogenesis from Immature Cotyledon Explants of Shea (Vitellaria paradoxa G,)
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作者 Paul Kwasi Krah Adu-Gyamfi Michael Teye Barnor +5 位作者 Abu Mustapha Dadzie Samuel Lowor Stephen Yaw Opoku Kwabena Opoku-Ameyaw Matilda Bissah Francis Kwame Padi 《Journal of Agricultural Science and Technology(B)》 2012年第11期1171-1176,共6页
Long juvenile phase and lack of effective protocols for large scale vegetative propagation are limitations to domestication and improvement of the shea tree. The present study seeks to develop a protocol for plant reg... Long juvenile phase and lack of effective protocols for large scale vegetative propagation are limitations to domestication and improvement of the shea tree. The present study seeks to develop a protocol for plant regeneration of shea (Vitellaria paradoxa) from immature cotyledon explants. Embryogenic callus cultures were induced on Murashige and Skoog medium (MS) containing 3% sucrose, 0.24% Phytagel, and various concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D) after four weeks of culture in darkness. Rates of embryogenic callus induction were significantly affected by the addition of 2, 4-D to the medium. Within 28 days of culture, the highest percentage of embyogenic calli (77.61%) occurred on MS media containing 0.45 ~tM of 2,4-D in the dark. Somatic embryos were obtained by culturing embryogenic callus (in the dark) on MS medium fortified with 3% sucrose, 0.24% phytagel and devoid of growth regulators. Culturing at 16 h photoperiod restricted both the induction of embryogenic calli cultures and somatic embryos. Somatic embryos germinated, developed shoots and rooted vigorously on MS medium devoid of growth regulators. Germinated plantlets were acclimatized, successfully. 展开更多
关键词 Embryogenic callus MICRO-PROPAGATION Sapoteaceae shea tree somatic embryos.
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Suppression to the cross-channel interference based on the short time Fourier transform
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作者 何密 Nian Yongjian +1 位作者 Li Yongzhen Xiao Shunping 《High Technology Letters》 EI CAS 2013年第3期309-314,共6页
A new cross-channel interference suppression method is proposed to decrease the cross-channel interference in beat signals based on the short time Fourier transform (STY3") and the inverse short time Fourier transf... A new cross-channel interference suppression method is proposed to decrease the cross-channel interference in beat signals based on the short time Fourier transform (STY3") and the inverse short time Fourier transform (ISTFT) when the dual-orthogonal polarimetric frequency-modulated continu- ous wave (FMCW) radar adopts the opposite-slope linear frequency modulation signal pair in the simultaneous measurement mode. The STFT is applied only on the signals in the cross-interference intervals in the four polarimetric channels to decrease the computation complexity. A mask matrix for suppressing the interference is constructed using the constant false alarm ratio (CFAR) detection on the spectrograms by the STFY. The simulative results show that the cross-channel interference is effi- ciently suppressed by the proposed method. The comparison between the proposed method and the rejection method verifies the improved performance of the proposed method. 展开更多
关键词 simultaneous measurement cross-channel interference suppression the short timeFourier transform (STFT) the inverse short time Fourier transform (ISTFT)
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COMPARISON OF ENERGY RESERVES AND UTILIZATION IN LIPOSCELIS BOSTRYCHOPHILA POPULATIONS SELECTED FOR TOLERANCE TO CONTROLLED ATMOSPHERE 被引量:2
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作者 王进军 赵志模 +2 位作者 邓新平 丁伟 李隆术 《Entomologia Sinica》 CSCD 2002年第4期41-46,共6页
One population of Liposcelis bostrychophila Badonnel (CA selected) was exposed to a controlled atmosphere(CA) (35% CO 2+1% O 2, balance N 2) for 30 generations. Another population (control) was reared under natural... One population of Liposcelis bostrychophila Badonnel (CA selected) was exposed to a controlled atmosphere(CA) (35% CO 2+1% O 2, balance N 2) for 30 generations. Another population (control) was reared under natural atmospheric conditions. Reserves of triacylglycerol, polysaccharides and free amino acids were evaluated in adults of the CA selected and the control populations in generations F 15 and F 30 The utilization rate of triacylglycerol and polysaccharides in the CA exposure were also determined in generation F 30. The results indicate that the reserves of triacylglycerol and polysaccharides increased significantly during selection for CA tolerance; the higher the tolerance level, the greater the reserves. A total of 15 free amino acids constituents were detected in both populations. The total amino acid content in the CA selected population was obviously higher than that in the control population. Exposure of this population to a controlled atmosphere was associated with a steady utilization of reserves. In contrast, the unselected population responded to the controlled atmosphere by accelerated utilization of triacylglycerol and polysachharides. Comparison of utilization rates during CA exposure showed that triacylglycerol is the main energy source, and polysaccharides contribute only a small extent to the metabolic energy supply. 展开更多
关键词 Liposcelis bostrychophila TRIACYLGLYCEROL POLYSACCHARIDE amino acid TOLERANCE controlled atmosphere
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A Piecewise Curvature-Corrected CMOS Bandgap Reference with Negative Feedback
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作者 李景虎 王永生 +1 位作者 喻明艳 叶以正 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第10期1974-1979,共6页
A piecewise curvature-corrected bandgap reference (BGR) with negative feedback is proposed. It features employing a temperature-dependent resistor ratio technique to get a piecewise corrected current, which corrects... A piecewise curvature-corrected bandgap reference (BGR) with negative feedback is proposed. It features employing a temperature-dependent resistor ratio technique to get a piecewise corrected current, which corrects the nonlinear temperature dependence of the first-order BGR. The piecewise corrected current generator also forms negative feedback to improve the line regulation and power supply rejection (PSR). Measurement results show the proposed BGR achieves a maximum temperature coefficient (TC) of 21.2ppm/℃ without trimming in the temperature range of - 50-125℃ and a PSR of - 60dB at 2.6V supply voltage. The line regulation is 0.8mV/V in the supply range of 2.6-5.6V. It is successfully implemented in an SMIC 0.35μm 5V n-well digital CMOS process with the effective chip area of 0.04mm^2 and power con- sumption of 0.18mW. The reference is applied in a 3,5V optical receiver trans-impedance amplifier. 展开更多
关键词 piecewise curvature-corrected bandgap reference line regulation PSR temperature coefficient
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