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Science China(Life Sciences) 2008年第5期51卷 445-452页

作者： LI ZiHui1,2, FENG XianMin1, LU SiQi1, ZHANG Fan1, WANG FengYun1 & HUANG Song1 1 Department of Pathogenic Biology, Capital Medical University, Beijing 100069, China 2 Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101100, China Department of Pathogenic Biology Capital Medical University Beijing China Beijing Tuberculosis and Thoracic Tumor Research Institute Beijing China

To clarify the phylogenetic relationships and species status of Pneumocystis, the 5.8S rRNA gene and the internal transcribed spacers (ITS, 1 and 2) of Pneumocystis rRNA derived from rat, gerbil and human were amplified, cloned and sequenced. The genetic distance matrix of six Pneumocystis species compared with other fungi like Taphrina and Saccharomyces indicated that the Pneumocystis genus contained multiple species including Pneumocystis from gerbil. The phylogenetic tree also showed that Pneumocystis from human and monkey formed one group and four rodent Pneumocystis formed another group. Among the four members, Pneumocystis wakefieldiae was most closely related to Pneumocystis murina and Pneumocystis carinii, and was least related to gerbil Pneumocystis.

关键词： Pneumocystis phylogeny 5.8S rRNA gene internal transcribed spacers

Blue emitting exciplex for yellow and white organic light‑emitting diodes

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Frontiers of Optoelectronics 2023年第4期16卷 191-203页

作者： Kavya Rajeev C.K.Vipin Anjali K.Sajeev Atul Shukla Sarah K.M.McGregor Shih‑Chun Lo Ebinazar B.Namdas K.N.Narayanan Unni Centre for Sustainable Energy Technologies CSIR-National Institute for Interdisciplinary Science and TechnologyThiruvananthapuram 695019India Academy of Scientifc and Innovative Research(AcSIR) Ghaziabad 201002India Centre for Organic Photonics&Electronics The University of QueenslandBrisbaneQLD 4072Australia School of Mathematics and Physics The University of QueenslandBrisbaneQLD 4072Australia School of Chemistry and Molecular Biosciences The University of QueenslandBrisbaneQLD 4072Australia

White organic light-emitting diodes(WOLEDs)have several desirable features,but their commercialization is hindered by the poor stability of blue light emitters and high production costs due to complicated device structures.Herein,we investigate a standard blue emitting hole transporting material(HTM)N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidine(NPB)and its exciplex emission upon combining with a suitable electron transporting material(ETM),3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole(TAZ).Blue and yellow OLEDs with simple device structures are developed by using a blend layer,NPB:TAZ,as a blue emitter as well as a host for yellow phosphorescent dopant iridium(III)bis(4-phenylthieno[3,2-c]pyridinato-N,C2')acetylacetonate(PO-01).Strategic device design then exploits the ambipolar charge transport properties of tetracene as a spacer layer to connect these blue and yellow emitting units.The tetracene-linked device demonstrates more promising results compared to those using a conventional charge generation layer(CGL).Judicious choice of the spacer prevents exciton difusion from the blue emitter unit,yet facilitates charge carrier transport to the yellow emitter unit to enable additional exciplex formation.This complementary behavior of the spacer improves the blue emission properties concomitantly yielding reasonable yellow emission.The overall white light emission properties are enhanced,achieving CIE coordinates(0.36,0.39)and color temperature(4643 K)similar to daylight.Employing intermolecular exciplex emission in OLEDs simplifes the device architecture via its dual functionality as a host and as an emitter.

关键词： Organic light-emitting diodes Dual functional exciplex spacers Device design strategy Blue exciplex Yellow OLEDs White light emission

THE EFFECT OF SUBSTITUENT ON THE THERMAL PROPERTIES OF POLYESTERS CONSISTING OF AROMATIC TYPE SCHIFF BASE MESOGENIC UNITS AND POLYMETHYLENE spacers

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Chinese Journal of Polymer Science 1995年第1期13卷 51-58页

作者： Amar H.Al-Dujaili Iman F.Mustafa Amir T.Atto Department of Chemistry College of Education Ibn Al-Hytham University of Baghdad Baghdad P. O. Box 7358 IraqDepartment of Chemistry College of Education Ibn Al-Hytham University of Baghdad Baghdad P. O. Box 7358 IraqDepartment of Chemistry College of Sciences University of Sadaam Baghdad Iraq

Polyesters consisting of substituted aromatic type Schiff base mesogenic unit andpolymethylene spacers were synthesized and their thermal transitions and liquid crystallineproperties were studied. The liquid crystalline behaviour has been characterized by differentialscanning calorimetry (DSC) and optical polarizing microscopy. Structural broadening bysubstitution of methoxy group in 2, 2' positions of the mesogenic core produce polymers withlower transition temperatures. Polymers synthesized from ortho and meta substituted phenylenediamine did not form a liquid crystal phase.

关键词： Liquid crystal polymer Polyesters Aromatic type schiff base Mesogenic units spacers

Characterization of Xanthomonas citri pv.citri from China based on spoligotyping

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Horticultural Plant Journal 2022年第6期8卷 727-736页

作者： Wenting Li Zhenxi Li Jiaquan Huang Meirong Xu Zheng Zheng Xiaoling Deng Guangdong Province Key Laboratory of Microbial Signals and Disease Control College of Plant ProtectionSouth China Agricultural UniversityGuangzhou 510642China

Xanthomonas citri pv.citri(Xcc),a gram-negative bacterium,is the causal agent of citrus canker,one of the most devastating diseases threatening the citrus industry worldwide.Understanding the diversity and population structure of Xcc is a prerequisite for disease epidemiological monitoring and effective disease management.Recent characterization of the clustered regularly interspaced short palindromic repeats(CRISPR)/cas(CRISPR-associated proteins genes)system with a highly variable repeat number among species provides a new molecular typing method for bacterial genetic analysis.In this study,we performed systematic in silico analyses of 28 Xcc genomes and identified a credible CRISPR/cas in Xcc strains.Further analysis of CRISPR polymorphisms(repeat number and spacer types)in 129 Xcc A strains collected from six provinces in China identified 15 types of CRISPR arrays with 25 spacers.Phylogenetic analysis of Xcc strains based on the CRISPR locus produced a more reliable and accurate typing result compared to the commonly used loci.In addition,seven associated cas genes—cas1,cas2,cas3,cas4,cas5,cas7(csd2),and cas8(csd1)—were found located adjacent to the CRISPR array.BLAST results showed>99%similarity of seven cas genes among Xcc strains.Homology analysis of spacer sequences showed that six spacers had possible phage/prophage origin.The characterization of the CRISPR/cas system among Xcc strains provided an updated strain typing method for Xcc diversity analysis and yielded a panoramic view of CRISPR evolution for further studies of Xcc-phage interactions.

关键词： Xanthomonas citri pv.citri CRISPR Diversity spacers Typing method

Phylogenetic Relationships of <i>Termitomyces aurantiacus</i>Inferred from Internal Transcribed spacers DNA Sequences

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Advances in Bioscience and Biotechnology 2015年第5期6卷 358-367页

作者： Shafiquzzaman Siddiquee Kobun Rovina Laila Naher Kenneth F. Rodrigues Md Akhter Uzzaman Biotechnology Research Institute Universiti Malaysia Sabah Kota Kinabalu Malaysia Faculty of Agro-Based Industry Universiti Malaysia Kelantan Jeli Campus-17600 Kelantan Malaysia Planning and Development Division Bangladesh Atomic Energy Commission Dhaka Bangladesh

Fungus-growing termites cultivate species of the mutualistic basidiomycete genus Termitomyces on a substrate called the fungal comb. Identification of fungal species based on morphological features is complicated, tedious, and prone to errors. As an alternative, nuclear ribosomal DNA sequences consisting of the internal transcribed spacers (ITS1 and ITS2) and 5.8S rDNA were used to identify Malaysian isolates of Termitomyces sp. The morphological characteristics and molecular data indicate that Malaysian Termitomyces isolated is clearly monophyletic and belongs to the Tricholomataceae family. The Malaysian isolates analyzed in this study represent the termite fungus species called T. aurantiacus.

关键词： Fungal Comb Internal Transcribed spacers Morphological Feature Phylogenetic Relationship

Imaging characteristics of metallic interbody spacers: in vitro score evaluation of susceptibility artifacts considering different MRI sequences

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Journal of Biomedical Science and Engineering 2010年第2期3卷 181-186页

作者： T. Ernstberger G. Heidrich G. Buchhorn 不详

Aim: Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium, carbon or cobalt-chrome, which can affect the post- fusion MRI scans. Implant-related susceptibility artifacts can decrease the quality of MRI scans, thwar- ting proper evaluation. This cadaver study aimed to demonstrate the extent that implant-related MRI artifacting affects the post-fusion evaluation of intervertebral spacers. Methods: In a cadaveric porcine spine, we evaluated the post-implantation MRI scans of 2 metallic intervertebral spacers (TiAL6V4, CoCrMo) that differed in shape, material, surface qualities and implantation technique. A spacer made of human cortical bone was used as a control. The median sagittal MRI slice was divided into 12 regions of interest (ROI). Results: No significant differences were found on 15 different MRI sequences read independently by an interobserver-validated team of specialists (P>0.05). Artifact-affected image quality was rated on a score of 0-1-2. A maximum score of 24 points (100%) was possible. Turbo spin echo sequences produced the best scores for all spacers and the control. Only the control achieved a score of 100%. The titanium and cobalt-chrome spacers scored 62.5% and 50%, respectively. Conclusions: Our scoring system allowed us to create an implant-related rank- ing of MRI scan quality in reference to the control that was independent of artifact dimensions. Even with turbo spin echo sequences, the susceptibility artifacts produced by the metallic spacers showed a high degree of variability. Despite optimum sequen- cing, implant design and material are relevant factors in MRI artifacting.

关键词： Intervertebral spacers Metallic Implant Materials MRI Susceptibility Artifacts

Internal transcribed spacer guided multiplex PCR for species identification of Convolvulus prostratus and Evolvulus alsinoides

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Acta Pharmaceutica Sinica B 2016年第3期6卷 253-258页

作者： Sonal Sharma Neeta Shrivastava B.V. Patel Pharmaceutical Education and Research Development (PERD) Centre Sarkhej-Gandhinagar Highway Nirma University

Shankhpushpi is a reputed drug from an Indian system of medicine for treating mental disorders and enhancing memory. Two herbs, namely Convolvulus prostratus Forssk. and Evolvulus alsinoides(L.) L., are commonly known as Shankhpushpi. Ambiguous vernacular identity can affect the scientific validity of the Shankpushpi-based herbal drug therapy. In the present investigation, a novel and sensitive multiplex PCR method based on polymorphism in the internal transcribed spacer(ITS) region was developed to establish the molecular identity of C. prostratus and E. alsinoides. DNA was isolated and the ITS region was amplified, sequenced and assembled. Sequences were aligned to identify variable nucleotides in order to develop plant-specific primers. Primers were validated in singleplex reactions and eventually a multiplex assay was developed. This assay was tested for sensitivity and validated by amplifying DNA isolated from the simulated blended powdered plant material. Primers developed for C. prostratus resulted into a 200 bp amplicon and 596 bp for E. alsinoides. The assay was found to be sensitive enough for amplification of low quantities of DNA. The method can detect 10% of the mixing of plants with each other in blended material. This PCR assay can be used for rapid botanical identification of Shankhpushpi plant materials and will improve evidence-based herbal drug therapy.

关键词： PCR Internal transcribed spacers Shankhpushpi Botanical identification Adulteration Substitution Herbal drugs DNA barcoding

SYNTHESIS AND PROPERTIES OF NEW MESOGEN-JACKETED LIQUID CRYSTALLINE POLYMERS

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Chinese Journal of Polymer Science 2000年第2期18卷 139-148页

作者： Qi-ding Mi Qi-feng Zhou Department of Polymer Science & Engineering, College of Chemistry Peking University, Beijing 100871, China 北京大学北京

Some new mesogen-jacketed liquid crystalline polymers (MJLCP) with polymer backbones, spacers, and mesogenic units of different structures were synthesized by radical polymerization. The mesomorphic behavior of these polymers was examined using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Their liquid crystallinity is influenced by the variation of polymer backbone, spacer, mesogenic unit and its terminal groups. The results show that 1) a more flexible polymer main-chain is more favorable to the formation of a liquid crystal phase, while 2) a flexible spacer will decrease the 'Jacket Effect' and the liquid crystallinity and 3) a subtle modification of the terminal groups on the mesogenic unit may also have a significant influence on properties of the polymers.

关键词： mesogen-jacketed liquid crystalline polymers polymer backbones spacers mesogenic units liquid crystallinity

Phylogenetic status of Pneumocystis from corticosteroid-treated gerbils

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Science China(Life Sciences) 2010年第10期53卷 1239-1246页

作者： RODNEY D Adam Department of Medicine and Immunobiology University of Arizona College of Medicine

Pneumocystis spp. infect the lungs of multiple mammalian species and cause disease in immunosuppressed individuals. The Pneumocystis isolates that have been studied to date fall into two major clades, those from primates and those from rodents. Within each of these clades, different species have been described on the basis of host specificity and differences in sequence and morphology. Here, we demonstrate that dexamethasone immunosuppression consistently results in histologically apparent lung infection in gerbils (28/35 animals). Sequence analysis of the 18S, 5.8S and internal transcribed spacer regions of the rDNA and a portion of the mitochondrial large subunit rDNA demonstrated that this gerbil Pneumocystis is grouped with other rodent Pneumocystis spp., but is distinct from them. Our results suggest that gerbil Pneumocystis differs sufficiently from Pneumocystis species found in other rodents to be considered a separate species.

关键词： 5.8S rRNA gene gerbil internal transcribed spacers (ITS) mitochondrial large subunit (mtLS) rRNA gene 18S rRNA gene Pneumocystis

ERROR ANALYSIS IN DIFFERENTIAL QUADRATURE METHOD

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Transactions of Nanjing University of Aeronautics and Astronautics 1994年第2期11卷 194-200页

作者： He Beiqing(College of Science,NUAA 29 Yudao Street,Nanjing 210016,P.R.China)Wang Xinwei(Department of Aircraft Engineering ,NUAA 29 Yudao Street,Nanjing 210016,P.R.China)

Error estimation for the differential quadrature (DQ)with various sets of grid spacing is presented. A general formula is given to compute the weighting coefficients directly. It is found that the maximum error of the Do method with roots of Chebyshev polynomials including two end POints (-1 and + 1 ) is the smallest among the several sets of grid spacing investigated herein.

关键词： error estimate weight grid spacers differential quadrature harmonic differential quadrature