WorldWideScience

Sample records for amplified fragment length

  1. Amplified fragment length polymorphism and virulence polymorphism in Puccinia hordei

    Science.gov (United States)

    Puccinia hordei is the causal agent of barley leaf rust. To study the genetic diversity in P. hordei, 45 isolates with diverse virulence patterns and geographical origins were analyzed using amplified fragment length polymorphism markers. Two pathotypes of Puccinia graminis f. sp. tritici and one is...

  2. Amplified-fragment length polymorphism fingerprinting of Mycoplasma species

    DEFF Research Database (Denmark)

    Kokotovic, Branko; Friis, N.F.; Jensen, J.S.;

    1999-01-01

    Amplified-fragment length polymorphism (AFLP) is a whole-genome fingerprinting method based on selective amplification of restriction fragments. The potential of the method for the characterization of mycoplasmas was investigated in a total of 50 strains of human and animal origin, including......I restriction endonucleases and subsequent ligation of corresponding site-specific adapters. The amplification of AFLP templates with a single set of nonselective primers resulted in reproducible fingerprints of approximately 60 to 80 fragments in the size range of 50 to 500 bp, The method was able to...

  3. Amplified-fragment length polymorphism fingerprinting of Mycoplasma species

    DEFF Research Database (Denmark)

    Kokotovic, Branko; Friis, N.F.; Jensen, J.S.; Ahrens, Peter

    1999-01-01

    Amplified-fragment length polymorphism (AFLP) is a whole-genome fingerprinting method based on selective amplification of restriction fragments. The potential of the method for the characterization of mycoplasmas was investigated in a total of 50 strains of human and animal origin, including...... Mycoplasma genitalium (n = 11), Mycoplasma pneumoniae (n = 5), Mycoplasma hominis (n = 5), Mycoplasma hyopneunmoniae (n = 9), Myco plasma flocculare (n = 5), Mycoplasma hyosynoviae (n = 10), and Mycoplasma dispar (n = 5), AFLP templates were prepared by the digestion of mycoplasmal DNA with BglII and Mfe...... discriminate the analyzed strains at species and intraspecies levels as well, Each of the tested Mycoplasma species developed a banding pattern entirely different from those obtained from other species under analysis, Subtle intraspecies genomic differences were detected among strains of all of the Mycoplasma...

  4. Amplified fragment length polymorphism and pulsed field gel electrophoresis for subspecies differentiation of Serpulina pilosicoli

    DEFF Research Database (Denmark)

    Møller, Kristian; Jensen, Tim Kåre; Boye, Mette; Leser, T.D.; Ahrens, Peter

    Pulsed field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP) were compared for their ability to differentiate between 50 porcine Serpulina pilosicoli isolates. Both techniques were highly sensitive, dividing the isolates into 36 and 38 groups, respectively. Due to the...

  5. Genotyping and genetic diversity of Arcobacter butzleri by amplified fragment length polymorphism (AFLP) analysis

    DEFF Research Database (Denmark)

    On, Stephen L.W.; Atabay, H.I.; Amisu, K.O.;

    2004-01-01

    Aims: To investigate the potential of amplified fragment length polymorphism (AFLP) profiling for genotyping Arcobacter butzleri and to obtain further data on the genetic diversity of this organism. Methods and Results: Seventy-three isolates of Danish, British, Turkish, Swedish, Nigerian and Nor...

  6. Evaluation of Amplified Fragment Length Polymorphism for Differentiation of Avian Mycoplasma Species

    OpenAIRE

    Hong, Y; Garcia, M.; Levisohn, S; Lysnyansky, I.; Leiting, V.; Savelkoul, P. H. M.; Kleven, S. H.

    2005-01-01

    Amplified fragment length polymorphism (AFLP) was used for typing avian mycoplasma species. Forty-four avian mycoplasma strains were successfully typed into eight distinct groups, with each representing a different species. Homology of AFLP patterns of 35% or less was used as a cutoff value to differentiate avian mycoplasma strains into different species.

  7. GENETIC VARIATIONS AMONG AQUILARIA SPECIES AND GYRINOPS VERSTEEGII USING AMPLIFIED FRAGMENT LENGTH POLYMORPHISM MARKERS

    OpenAIRE

    NURITA TORUAN-MATHIUS; DEWI RAHMAWATI; ANIDAH

    2009-01-01

    Aquilaria sp. (Thymelaeaceae) is the most valuable non wood production of forestry plant in Indonesia. It produces a fragrant resin when subjected to fungal attack and has been traded internationally known as gaharu. Knowledge of genetic diversity and relationship among species and genus is important for breeding purposes and species conservation. In this study, genetic variabilityof six Aquilaria species were analyzed using the AmplifiedFragment Length Polymorphism (AFLP) markers. Ten ...

  8. Fluorescent Amplified Fragment Length Polymorphism Probabilistic Database for Identification of Bacterial Isolates from Urinary Tract Infections

    OpenAIRE

    Kassama, Yankuba; Rooney, Paul J.; Goodacre, Royston

    2002-01-01

    The ability of the fluorescent amplified fragment length polymorphism (FAFLP) technique to identify bacterial isolates from urinary tract infections (UTIs) was investigated. FAFLP was carried out using the single primer combination MseI plus CT and EcoRI plus 0, and information-rich FAFLP profiles were generated from all 69 UTI isolates studied, which comprised both gram-negative and gram-positive bacteria encompassing eight genera. The genetic relatedness of these 69 bacteria was determined ...

  9. Fluorescent Amplified Fragment Length Polymorphism Analysis of Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis Isolates

    OpenAIRE

    Hill, Karen K.; Ticknor, Lawrence O.; Okinaka, Richard T.; Asay, Michelle; Blair, Heather; Bliss, Katherine A.; Laker, Mariam; Pardington, Paige E.; Richardson, Amber P.; Tonks, Melinda; Beecher, Douglas J.; Kemp, John D.; Kolstø, Anne-Brit; Wong, Amy C. Lee; Keim, Paul

    2004-01-01

    DNA from over 300 Bacillus thuringiensis, Bacillus cereus, and Bacillus anthracis isolates was analyzed by fluorescent amplified fragment length polymorphism (AFLP). B. thuringiensis and B. cereus isolates were from diverse sources and locations, including soil, clinical isolates and food products causing diarrheal and emetic outbreaks, and type strains from the American Type Culture Collection, and over 200 B. thuringiensis isolates representing 36 serovars or subspecies were from the U.S. D...

  10. Genomic variations of Mycoplasma capricolum subsp capripneumoniae detected by amplified fragment length polymorphism (AFLP) analysis

    DEFF Research Database (Denmark)

    Kokotovic, Branko; Bolske, G.; Ahrens, Peter; Johansson, K.E.

    2000-01-01

    The genetic diversity of Mycoplasma capricolum subsp. capripneumoniae strains based on determination of amplified fragment length polymorphisms (AFLP) is described. AFLP fingerprints of 38 strains derived from different countries in Africa and the Middle East consisted of over 100 bands in the size...... found by 16S rDNA analysis. The present data support previous observations regarding genetic homogeneity of M. capricolum subsp. capripneumoniae, and confirm the two evolutionary lines of descent found by analysis of 16S rRNA genes....

  11. Fluorescent Amplified Fragment Length Polymorphism Subtyping of Multiresistant Salmonella enterica Serovar Typhimurium DT104

    OpenAIRE

    Lawson, Andrew J.; Stanley, John; Threlfall, E. John; Desai, Meeta

    2004-01-01

    Fluorescent amplified fragment length polymorphism (FAFLP) subtyping analysis was used to genotype multiresistant Salmonella enterica serovar Typhimurium definitive phage type 104. Thirteen distinct FAFLP profiles were found among 85 isolates exhibiting identical pulsed-field gel electrophoresis (PFGE) profiles. A single FAFLP profile was shared by 93% of outbreak-associated isolates and 82% of sporadic isolates. This study demonstrates the value of FAFLP as a high-resolution tool for epidemi...

  12. Analysis of genetic diversity identified by amplified fragment length polymorphism marker in hybrid wheat.

    Science.gov (United States)

    Ejaz, M; Qidi, Z; Gaisheng, Z; Na, N; Huiyan, Z; Qunzhu, W

    2015-01-01

    Amplified fragment length polymorphism markers were used to assess genetic diversity in 10 male sterile wheat crop lines (hetero-cytoplasm with the same nucleus) in relation to a restorer wheat line. These male sterile lines were evaluated using 64 amplified fragment length polymorphism primer combinations, and 13 primers produced polymorphic bands, generating a total 682 fragments. Of the 682 fragments, 113 were polymorphic. The polymorphic information content and marker index values demonstrated the utility of the primer combinations used in the present study. Unweighted pair group method with arithmetic mean and principal coordinate analysis of the genotypic data revealed clustering of accessions based on genetic relationships, and accessions were separated into 2 groups with their restorer line. Jaccard's similarity coefficient values suggested good variability among the male sterile lines, indicating their utility in breeding programs. The fallouts of analysis of molecular variance showed large within-group population variation, accounting for 77% of variation, while among-group comparison accounted for 23% of the total molecular variation, which was statistically significant. The molecular diversity observed in this study will be useful for selecting appropriate accessions for plant improvement and hybridization through molecular-breeding approaches and for developing suitable conservation strategies. PMID:26345825

  13. Application of fluorescent amplified fragment length polymorphism for comparison of human and animal isolates of Yersinia enterocolitica

    DEFF Research Database (Denmark)

    Fearnley, C.; On, S.L.W.; Kokotovic, Branko; Manning, G.; Cheasty, T.; Newell, D. G.

    2005-01-01

    An amplified fragment length polymorphism (AFLP) method, developed to genotype Yersinia enterocolitica, has been used to investigate 70 representative strains isolated from humans, pigs, sheep, and cattle in the United Kingdom. AFLP primarily distinguished Y enterocolitica strains according to th...

  14. [Recent advances of amplified fragment length polymorphism and its applications in forensic botany].

    Science.gov (United States)

    Li, Cheng-Tao; Li, Li

    2008-10-01

    Amplified fragment length polymorphism (AFLP) is a new molecular marker to detect genomic polymorphism. This new technology has advantages of high resolution, good stability, and reproducibility. Great achievements have been derived in recent years in AFLP related technologies with several AFLP expanded methodologies available. AFLP technology has been widely used in the fields of plant, animal, and microbes. It has become one of the hotspots in Forensic Botany. This review focuses on the recent advances of AFLP and its applications in forensic biology. PMID:18979924

  15. GENETIC VARIATIONS AMONG AQUILARIA SPECIES AND GYRINOPS VERSTEEGII USING AMPLIFIED FRAGMENT LENGTH POLYMORPHISM MARKERS

    Directory of Open Access Journals (Sweden)

    NURITA TORUAN-MATHIUS

    2009-01-01

    Full Text Available Aquilaria sp. (Thymelaeaceae is the most valuable non wood production of forestry plant in Indonesia. It produces a fragrant resin when subjected to fungal attack and has been traded internationally known as gaharu. Knowledge of genetic diversity and relationship among species and genus is important for breeding purposes and species conservation. In this study, genetic variabilityof six Aquilaria species were analyzed using the AmplifiedFragment Length Polymorphism (AFLP markers. Ten AFLP primercombinations amplified 1353 DNA fragments ranging in size from100 to 350 bp of which 1285 (95% of them were polymorphic. Genetic similarities among Aquilaria sp. consisted of A. malaccensis, A. beccariana, A. microcarpa, and A. crassna ranged from 63.90 to 72.00 % based on Dice coefficient. The dendrogram derivedby the unweighted pair group method with arithmetic mean of germplasm analysis were clustered into two main groups. Hence, a genetic variation among species is quiet high. Bootstrap valuesfor the groups supported 70% of the cluster using a linear relationship equation of (r = 0.724, P < 0.0001 was observedbetween known pedigrees and AFLP-derived genetic similarityfor 136 pairwise comparisons of Aquilaria species. For example, A. malacensis and A. microcarpa have the highest genetic similarity (72.00% compared with another Aquilaria species. Primer pairs E-ACG/M-CTA produced a specific fragment for A. beccariana (850 bp, A. crasna (550 bp, 180 bp, and 140 bp, A. malaccencis (1500 bp, A. microcarpa (250 bp and Gyrinops versteegii (150 bp. Primer pairs E-ACG/M-CAA produced a specific DNA fragment only for A. beccariana (1500 bp and 100 bp. Primer pairs E-ACC/M-CAC also produced only specific fragment for A. crassna (1500 bp. Study showed the usefulness of AFLPanalysis in Aquilaria sp. and its potential application for breedingand species conservation. Further, molecular diversity estimated in the present study combined with the datasets on other

  16. A NEW APPROACH TO GENE DIAGNOSIS OF DUCHENNE/BECKER MUSCULAR DYSTROPHY AMPLIFIED FRAGMENT LENGTH POLYMORPHISMS

    Institute of Scientific and Technical Information of China (English)

    许顺斌; 黄尚志; 罗会元

    1994-01-01

    Four (CA), repeats, located in introns,44,45,49 and 50 of the dystrophin gene,were evaluated in Chinese.These loci are highly polymorphic,with polymorphism information contents of 0.872,0.772,0.870 and 0.718,respectively.All four loci can be easily amplified and labelled using two duplex PCR reactions with α-32P-dCTP and can be detected by denaturing polyacrylamide gel electrophoresis.Using these four loci and the two polymorphic(CA)n repeats located at the 5′ and 3′ ends of the dystrophin gene,we have developed a new PCR-based procedure-Amp-FLP( amplified fragment length polymorphism)linkage analysis for the gene diagnosis of DMD/BMD.This method can detect intragenic recombination rapidly and efficiently and greatly improves the success rate of carrier deterction and prenatal diagnosis in non-deletion DMD/BMD families.All of the loci used in this procedure are intragenic.In addition ,the loci in introns 44,45,49 and 50 are located in the deletion-prone region of the dystrophin gene,making them valuable and usefui in the identification of deletion mutations.Here we report one case of deletion detection using these four loci.

  17. Identification and characterization of some aromatic rice mutants using amplified fragment length polymorphism (AFLP) technique

    International Nuclear Information System (INIS)

    Accurate identifying of the genotypes is considered one of the most important mechanisms used in the recording or the protection of plant varieties. The investigation was conducted at the experimental form belonging to the egyptian Atomic Energy Authority, Inshas. The aim was to evaluate grain quality characteristics and molecular genetic variation using Amplified Fragment Length Polymorphism (AFLP) technique among six rice genotypes, Egyptian Jasmine aromatic rice cultivar and five aromatic rice mutants in (M3 mutagenic generation). Two mutation (Egy22 and Egy24) were selected from irradiated Sakha 102 population with 200 and 400Gy of gamma rays in the M2 generation, respectively, and three mutations ( Egy32, Egy33, and Egy34) were selected from irradiated Sakha 103 population with 200, 300, 400Gy of gamma rays in the M2 generation, respectively. The obtained results showed that the strong aroma was obtained for mutant Egy22 as compared with Egyptian Jasmine rice cultivar (moderate aroma). Seven primer combinations were used through six rice genotypes on the molecular level using AFLP marker. The size of AFLP Fragments Were Ranged from 51- 494bp. The total number of amplified bands was 997 band among them 919 polymorphic bans representing 92.2%. The highest similarity index (89%) was observed between Egyptian Jasmine and Egy32 followed by (82%) observed between Egyptian Jasmine and Egy34. On the other hand, the lowest similarity index was (48%) between Egyptian Jasmine and Egy24. In six rice genotypes, Egy24 produced the highest number of the AFLP makers giving 49 unique markers (23 positive and 26 negative), then Egy22 showed 23 unique markers (27 positive and 6 negative) while Egy33 was characterized by 17 unique markers (12 positive and 5 negative). At last Egyptian Jasmine was discriminated by the lowest number of markets, 10 (6 positive and 4 negative). The study further confirmed that AFLP technique was able to differentiate rice genotypes by a higher number

  18. Veronaea botryosa: molecular identification with amplified fragment length polymorphism (AFLP) and in vitro antifungal susceptibility.

    Science.gov (United States)

    Badali, Hamid; Yazdanparast, Seyed Amir; Bonifaz, Alexandro; Mousavi, Bita; de Hoog, G Sybren; Klaassen, Corné H W; Meis, Jacques F

    2013-06-01

    Inter- and intraspecific genomic variability of 18 isolates of Veronaea botryosa originating from clinical and environmental sources was studied using amplified fragment length polymorphism (AFLP). The species was originally described from the environment, but several severe cases of disseminated infection in apparently healthy individuals have been reported worldwide. All tested strains of V. botryosa, identified on the basis of sequencing and phenotypic and physiological criteria prior to our study, were confirmed by AFLP analysis, yielding a clear separation of V. botryosa as a rather homogeneous group from related species. In vitro antifungal susceptibility testing resulted in MIC90s across all strains in increasing order posaconazole (0.25 μg/ml), itraconazole (1 μg/ml), voriconazole (4 μg/ml), terbinafine (4 μg/ml), caspofungin (8 μg/ml), anidulafungin (8 μg/ml), isavuconazole (16 μg/ml), amphotericin B (16 μg/ml), and fluconazole (32 μg/ml). Overall, the isolates showed a uniform pattern of low MICs of itraconazole and posaconazole, but high MICs for remaining agents. The echinocandins (caspofungin and anidulafungin) had no activity against V. botryosa. There was no statistically significant difference between susceptibilities of environmental (n = 11) and clinical (n = 7) isolates of V. botryosa (P > 0.05). PMID:23463524

  19. Genetic Variability in Rhizoctonia solani Isolated from Vitis vinifera Based on Amplified Fragment Length Polymorphism

    Directory of Open Access Journals (Sweden)

    Amparo Meza-Moller

    2011-01-01

    Full Text Available Problem statement: Rhizoctonia solani is a potential grapevine pathogen. In order to develop effective methods of control, it is necessary to document its genetic diversity. Approach: The objective of this study was to analyze the genetic variability of R. solani isolated from the rhizosphere of ungrafted V. vinifera var. perlette seedless planted in Sonora, Mexico using Amplified Fragment Length Polymorphism (AFLP. Results: In the selective amplification using eight primer combinations we obtained a total of 446 AFLP markers with a 100% polymorphism. Out of 41 isolates, 36 different AFLP patterns were observed and five were replicates of the same pattern. The dendrogram shows inter- and intrapopulation similarity indexes of 0.26, 0.98 and 0.31, 0.98, respectively. Six groups emerged from the principal components analysis, five of which were clearly defined, while the other one was spread out. Conclusion: We conclude that R. solani growing in Sonoran vineyards shows a high degree of genetic variability, even under similar environmental conditions.

  20. Genetic Variation among Isolates of Sarcocystis neurona, the Agent of Protozoal Myeloencephalitis, as Revealed by Amplified Fragment Length Polymorphism Markers

    OpenAIRE

    Elsheikha, H.M.; Schott, H. C.; Mansfield, L. S.

    2006-01-01

    Sarcocystis neurona causes serious neurological disease in horses and other vertebrates in the Americas. Based on epidemiological data, this parasite has recently emerged. Here, the genetic diversity of Sarcocystis neurona was evaluated using the amplified fragment length polymorphism (AFLP) method. Fifteen S. neurona taxa from different regions collected over the last 10 years were used; six isolates were from clinically diseased horses, eight isolates were from wild-caught opossums (Didelph...

  1. Delineation of Campylobacter concisus genomospecies by amplified fragment length polymorphism analysis and correlation of results with clinical data

    DEFF Research Database (Denmark)

    Aabenhus, R.; On, Stephen L.W.; Siemer, Berit L.; Permin, H.; Andersen, L.P.

    2005-01-01

    phenotypically indistinguishable but genetically distinct taxa (i.e., genornospecies) that may vary in pathogenicity. We examined 62 C concisus strains by amplified fragment length polymorphism (AFLP) profiling and correlated the results with clinical data. All C. concisus strains gave unique AFLP profiles, and...... numerical analysis of these data distributed the strains among four clusters. The clustering was of taxonomic significance: two clusters contained, respectively, the type strain (of oral origin) and a reference strain (from diarrhea) of each of the known genomospecies. Genomospecies 2 strains were more...

  2. High-resolution genotyping of Listeria monocytogenes by fluorescent amplified fragment length polymorphism analysis compared to pulsed-field gel electrophoresis, random amplified polymorphic DNA analysis, ribotyping, and PCR-restriction fragment length polymorphism analysis

    DEFF Research Database (Denmark)

    Vogel, Birte Fonnesbech; Fussing, V.; Ojeniyi, B.; Gram, Lone; Ahrens, Peter

    2004-01-01

    other methods. Isolates with identical DNA profiles were distributed across the spectrum of origin. It was not possible to associate certain types with specific food sectors or clinical cases, which is indicative of the spread of L. monocytogenes clones across species. Overall, AFLP fingerprinting was...... different origin. The AFLP technique was compared with three other molecular typing methods - ribotyping, random amplified polymorphic DNA analysis (RAPD), and pulsed-field gel electrophoresis (PFGE) - in terms of discriminatory ability. PCR-restriction fragment length polymorphism was included for...... virulence gene allele characterization. The 96 L. monocytogenes strains were divided into two major clusters by AFLP fingerprinting at a similarity level of 82% in concordance with the results of PFGE, RAPD, and ribotyping. One main cluster consisted of all of the 24 L. monocytogenes hly allele 1 strains...

  3. ALIS-FLP: Amplified ligation selected fragment-length polymorphism method for microbial genotyping

    DEFF Research Database (Denmark)

    Brillowska-Dabrowska, A.; Wianecka, M.; Dabrowski, Slawomir;

    2008-01-01

    only one specific restriction enzyme (TspRI) is used. The cohesive ends of the DNA fragments are ligated with two types of oligonucleotide. A long oligonucleotide containing the primer site and the specific 9 nt 3 prime end, which is complementary to specific 9 nt, cohesive 3 prime end of the Tsp......RI genomic DNA fragment, and a short, degenerated, oligonucleotide covering the remaining TspRI cohesive ends. Other cohesive ends are covered by a short degenerated oligonucleotide lacking the primer site. The ligation mixture is used as a template for amplification using a single primer corresponding to...... for differentiation of the organisms without previous knowledge of their DNA sequence. The usefulness of the method is confirmed by genotyping of 70 previously characterized clinical E. coli isolates. The grouping obtained was identical to the results of REA-PFGE. Versatility of the method is...

  4. Genetic differentiation of Octopus minor (Mollusca, Cephalopoda) off the northern coast of China as revealed by amplified fragment length polymorphisms.

    Science.gov (United States)

    Yang, J M; Sun, G H; Zheng, X D; Ren, L H; Wang, W J; Li, G R; Sun, B C

    2015-01-01

    Octopus minor (Sasaki, 1920) is an economically important cephalopod that is found in the northern coastal waters of China. In this study, we investigated genetic differentiation in fishery populations using amplified fragment length polymorphisms (AFLPs). A total of 150 individuals were collected from five locations: Dalian (DL), Yan-tai (YT), Qingdao (QD), Lianyungang (LY), and Zhoushan (ZS), and 243 reproducible bands were amplified using five AFLP primer combinations. The percentage of polymorphic bands ranged from 53.33 to 76.08%. Nei's genetic identity ranged from 0.9139 to 0.9713, and the genetic distance ranged from 0.0291 to 0.0900. A phylogenetic tree was constructed using the unweighted pair group method with arithmetic mean, based on the genetic distance. The DL and YT populations originated from one clade, while the QD, LY, and ZS populations originated from another. The results indicate that the O. minor stock consisted of two genetic populations with an overall significantly analogous FST value (0.1088, P < 0.05). Most of the variance was within populations. These findings will be important for more sustainable octopus fisheries, so that this marine resource can be conserved for its long-term utilization. PMID:26634529

  5. Amplified fragment length homoplasy: in silico analysis for model and non-model species

    Directory of Open Access Journals (Sweden)

    Poncet Bénédicte N

    2010-05-01

    Full Text Available Abstract Background AFLP markers are widely used in evolutionary genetics and ecology. However the frequent occurrence of non-homologous co-migrating fragments (homoplasy both at the intra- and inter-individual levels in AFLP data sets is known to skew key parameters in population genetics. Geneticists can take advantage of the growing number of full genome sequences available for model species to study AFLP homoplasy and to predict it in non-model species. Results In this study we performed in silico AFLPs on the complete genome of three model species to predict intra-individual homoplasy in a prokaryote (Bacillus thuringiensis ser. konkukian, a plant (Arabidopsis thaliana and an animal (Aedes aegypti. In addition, we compared in silico AFLPs to empirical data obtained from three related non-model species (Bacillus thuringiensis ser. israelensis, Arabis alpina and Aedes rusticus. Our results show that homoplasy rate sharply increases with the number of peaks per profile. However, for a given number of peaks per profile, genome size or taxonomical range had no effect on homoplasy. Furthermore, the number of co-migrating fragments in a single peak was dependent on the genome richness in repetitive sequences: we found up to 582 co-migrating fragments in Ae. aegypti. Finally, we show that in silico AFLPs can help to accurately predict AFLP profiles in related non-model species. Conclusions These predictions can be used to tackle current issues in the planning of AFLP studies by limiting homoplasy rate and population genetic estimation bias. ISIF (In SIlico Fingerprinting program is freely available at http://www-leca.ujf-grenoble.fr/logiciels.htm.

  6. Genome-wide macrosynteny among Fusarium species in the Gibberella fujikuroi complex revealed by amplified fragment length polymorphisms.

    Directory of Open Access Journals (Sweden)

    Lieschen De Vos

    Full Text Available The Gibberella fujikuroi complex includes many Fusarium species that cause significant losses in yield and quality of agricultural and forestry crops. Due to their economic importance, whole-genome sequence information has rapidly become available for species including Fusarium circinatum, Fusarium fujikuroi and Fusarium verticillioides, each of which represent one of the three main clades known in this complex. However, no previous studies have explored the genomic commonalities and differences among these fungi. In this study, a previously completed genetic linkage map for an interspecific cross between Fusarium temperatum and F. circinatum, together with genomic sequence data, was utilized to consider the level of synteny between the three Fusarium genomes. Regions that are homologous amongst the Fusarium genomes examined were identified using in silico and pyrosequenced amplified fragment length polymorphism (AFLP fragment analyses. Homology was determined using BLAST analysis of the sequences, with 777 homologous regions aligned to F. fujikuroi and F. verticillioides. This also made it possible to assign the linkage groups from the interspecific cross to their corresponding chromosomes in F. verticillioides and F. fujikuroi, as well as to assign two previously unmapped supercontigs of F. verticillioides to probable chromosomal locations. We further found evidence of a reciprocal translocation between the distal ends of chromosome 8 and 11, which apparently originated before the divergence of F. circinatum and F. temperatum. Overall, a remarkable level of macrosynteny was observed among the three Fusarium genomes, when comparing AFLP fragments. This study not only demonstrates how in silico AFLPs can aid in the integration of a genetic linkage map to the physical genome, but it also highlights the benefits of using this tool to study genomic synteny and architecture.

  7. Genotyping of human and porcine Yersinia enterocolitica, Yersinia intertmedia, and Yersinia bercovieri strains from Switzerland by amplified fragment length polymorphism analysis

    DEFF Research Database (Denmark)

    Kuehni-Boghenbor, Kathrin; On, Stephen L.W.; Kokotovic, Branko; Baumgartner, Andreas; Wassenaar, Trudy M.; Wittwer, Matthias; Bissig-Choisat, Beatrice; Frey, Joachim

    2006-01-01

    In this study, 231 strains of Yersinia enterocolitica, 25 strains of Y. intermedia, and 10 strains of Y. bercovieri from human and porcine sources (including reference strains) were analyzed using amplified fragment length polymorphism (AFLP), a whole-genome fingerprinting method for subtyping ba...

  8. Identification and molecular epidemiology of Campylobacter coli isolates from human gastroenteritis, food, and animal sources by amplified fragment length polymorphism analysis and Penner serotyping

    DEFF Research Database (Denmark)

    Siemer, B.L.; Nielsen, Elsa; On, Stephan L.w.

    2005-01-01

    Campylobacter coli is an infrequently studied but important food-borne pathogen with a wide natural distribution. We investigated its molecular epidemiology by use of amplified fragment length polymorphism (AFLP)-based genotyping and Penner serotyping. Serotype reference strains and 177 Danish is...

  9. Construction of the first high-density genetic linkage map of Salvia miltiorrhiza using specific length amplified fragment (SLAF) sequencing.

    Science.gov (United States)

    Liu, Tian; Guo, Linlin; Pan, Yuling; Zhao, Qi; Wang, Jianhua; Song, Zhenqiao

    2016-01-01

    Salvia miltiorrhiza is an important medicinal crop in traditional Chinese medicine (TCM). Knowledge of its genetic foundation is limited because sufficient molecular markers have not been developed, and therefore a high-density genetic linkage map is incomplete. Specific length amplified fragment sequencing (SLAF-seq) is a recently developed high-throughput strategy for large-scale SNP (Single Nucleotide Polymorphisms) discovery and genotyping based on next generation sequencing (NGS). In this study, genomic DNA extracted from two parents and their 96 F1 individuals was subjected to high-throughput sequencing and SLAF library construction. A total of 155.96 Mb of data containing 155,958,181 pair-end reads were obtained after preprocessing. The average coverage of each SLAF marker was 83.43-fold for the parents compared with 10.36-fold for the F1 offspring. The final linkage map consists of 5,164 SLAFs in 8 linkage groups (LGs) and spans 1,516.43 cM, with an average distance of 0.29 cM between adjacent markers. The results will not only provide a platform for mapping quantitative trait loci but also offer a critical new tool for S. miltiorrhiza biotechnology and comparative genomics as well as a valuable reference for TCM studies. PMID:27040179

  10. Use of Multienzyme Multiplex PCR Amplified Fragment Length Polymorphism Typing in Analysis of Outbreaks of Multiresistant Klebsiella pneumoniae in an Intensive Care Unit

    OpenAIRE

    van der Zee, Anneke; Steer, Niels; Thijssen, Eveline; Nelson, Jolande; van't Veen, Annemarie; Buiting, Anton

    2003-01-01

    We developed and optimized a new modified amplified fragment length polymorphism (AFLP) typing method to obtain a multibanding fingerprint that can be separated by agarose gel electrophoresis. Both to maximize the discriminatory power and to facilitate the computer-assisted analysis, bacterial DNA was digested with four different restriction enzymes. After ligation of adaptors to the DNA fragments, PCR testing of various single primers was performed. Two single primers that gave optimal resul...

  11. A High-Density Genetic Map of Tetraploid Salix matsudana Using Specific Length Amplified Fragment Sequencing (SLAF-seq)

    Science.gov (United States)

    Li, Min; Li, Yujuan; Wang, Ying; Ma, Xiangjian; Zhang, Yuan; Tan, Feng; Wu, Rongling

    2016-01-01

    As a salt-tolerant arbor tree species, Salix matsudana plays an important role in afforestation and greening in the coastal areas of China. To select superior Salix varieties that adapt to wide saline areas, it is of paramount importance to understand and identify the mechanisms of salt-tolerance at the level of the whole genome. Here, we describe a high-density genetic linkage map of S. matsudana that represents a good coverage of the Salix genome. An intraspecific F1 hybrid population was established by crossing the salt-sensitive “Yanjiang” variety as the female parent with the salt-tolerant “9901” variety as the male parent. This population, along with its parents, was genotyped by specific length amplified fragment sequencing (SLAF-seq), leading to 277,333 high-quality SLAF markers. By marker analysis, we found that both the parents and offspring were tetraploid. The mean sequencing depth was 53.20-fold for “Yanjiang”, 47.41-fold for “9901”, and 11.02-fold for the offspring. Of the SLAF markers detected, 42,321 are polymorphic with sufficient quality for map construction. The final genetic map was constructed using 6,737 SLAF markers, covering 38 linkage groups (LGs). The genetic map spanned 5,497.45 cM in length, with an average distance of 0.82 cM. As a first high-density genetic map of S. matsudana constructed from salt tolerance-varying varieties, this study will provide a foundation for mapping quantitative trait loci that modulate salt tolerance and resistance in Salix and provide important references for molecular breeding of this important forest tree. PMID:27327501

  12. Application of Amplified Fragment Length Polymorphism Fingerprinting for Taxonomy and Identification of the Soft Rot Bacteria Erwinia carotovora and Erwinia chrysanthemi

    OpenAIRE

    Avrova, Anna O; Hyman, Lizbeth J.; Toth, Rachel L.; Toth, Ian K

    2002-01-01

    The soft rot bacteria Erwinia carotovora and Erwinia chrysanthemi are important pathogens of potato and other crops. However, the taxonomy of these pathogens, particularly at subspecies level, is unclear. An investigation using amplified fragment length polymorphism (AFLP) fingerprinting was undertaken to determine the taxonomic relationships within this group based on their genetic relatedness. Following cluster analysis on the similarity matrices derived from the AFLP gels, four clusters (c...

  13. Mining candidate genes associated with powdery mildew resistance in cucumber via super-BSA by specific length amplified fragment (SLAF) sequencing

    OpenAIRE

    Peng ZHANG; Zhu, Yuqiang; Wang, Lili; CHEN, LIPING; Zhou, Shengjun

    2015-01-01

    Background Powdery mildew (PM) is the most common fungal disease of cucumber and other cucurbit crops, while breeding the PM-resistant materials is the effective way to defense this disease, and the recent development of modern genetics and genomics make us aware of that studying the resistance genes is the essential way to breed the PM high-resistance plant. With the ever increasing throughput of next-generation sequencing (NGS), the development of specific length amplified fragment sequenci...

  14. Characterization of Pseudomonas aeruginosa in Burn Patients Using PCR- Restriction Fragment Length Polymorphism and Random Amplified Polymorphic DNA Analysis

    Directory of Open Access Journals (Sweden)

    Abdolaziz Rastegar Lari

    2010-09-01

    Full Text Available One of the major opportunistic pathogens in patients with burninjuries is Pseudomonas aeruginosa, which causes severe infectionsin burned patients. The objective of the study was to examinethe molecular epidemiology of P. aeruginosa colonization inthe burn unit of Shahid Motahari Hospital in Tehran, Iran. Restrictionfragment length polymorphism (RFLP and random amplifiedpolymorphic DNA (RAPD analysis were employed tostudy 127 clinical and two environmental P. aeruginosa isolatescollected from January to June 2008. In RFLP, the PCR productsof 16S rRNA gene were digested with restriction enzyme Alu I,Hae III, and Rsa I, and the fragments generated were analyzed byagarose electrophoresis. Molecular typing by RFLP did show nodiscriminatory power for P. aeruginosa isolates, but RAPD-PCRrevealed eight different genotypes; RAPD1to RAPD8 in clinicaland environmental isolates. RAPD1 was the major genotype inclinical (n=64, 50.4% and environmental isolates (n=1, 50%.The findings suggest that RAPD might have a superior typeabilityand discriminatory power over RFLP to study P. aeruginusa.Moreover, they highlight the need for further attention to the controlof infection sources in Burn Units to prevent the transmissionof the bacterium.

  15. A High-Density Genetic Linkage Map for Cucumber (Cucumis sativus L.): Based on Specific Length Amplified Fragment (SLAF) Sequencing and QTL Analysis of Fruit Traits in Cucumber

    Science.gov (United States)

    Zhu, Wen-Ying; Huang, Long; Chen, Long; Yang, Jian-Tao; Wu, Jia-Ni; Qu, Mei-Ling; Yao, Dan-Qing; Guo, Chun-Li; Lian, Hong-Li; He, Huan-Le; Pan, Jun-Song; Cai, Run

    2016-01-01

    High-density genetic linkage map plays an important role in genome assembly and quantitative trait loci (QTL) fine mapping. Since the coming of next-generation sequencing, makes the structure of high-density linkage maps much more convenient and practical, which simplifies SNP discovery and high-throughput genotyping. In this research, a high-density linkage map of cucumber was structured using specific length amplified fragment sequencing, using 153 F2 populations of S1000 × S1002. The high-density genetic map composed 3,057 SLAFs, including 4,475 SNP markers on seven chromosomes, and spanned 1061.19 cM. The average genetic distance is 0.35 cM. Based on this high-density genome map, QTL analysis was performed on two cucumber fruit traits, fruit length and fruit diameter. There are 15 QTLs for the two fruit traits were detected. PMID:27148281

  16. Genetic relatedness among Campylobacter jejuni serotyped isolates of diverse origin as determined by numerical analysis of amplified fragment length polymorphism (AFLP) profiles

    DEFF Research Database (Denmark)

    Siemer, B.L.; Harrington, C.S.; Nielsen, E.M.;

    2004-01-01

    analysis of AFLP profiles derived from genomic DNA. Extensive genetic diversity was seen among the strains examined; however, 43 groups of isolates were identified at the 92% similarity (S-) level. Thirteen groups contained isolates from a single host, possibly representing genotypes of 'low risk' to human......Aims: To use amplified fragment length polymorphism (AFLP) analysis to evaluate the genetic relatedness among 254 Campylobacter jejuni reference and field strains of diverse origin representing all defined 'Penner' serotypes for this species. Methods and Results: Field strains (n = 207) from human...... diarrhoea and diverse animal and environmental sources were collected mainly through a National surveillance programme in Denmark and serotyped by use of the established 'Penner' scheme. Genetic relationships among these isolates, and the archetypal serotype reference strains, were assessed by numerical...

  17. Identification of Amplified Fragment Length Polymorphism (AFLP Markers Tightly Associated with Drought Stress Gene in Male Sterile and Fertile Salvia miltiorrhiza Bunge

    Directory of Open Access Journals (Sweden)

    Hongbo Guo

    2013-03-01

    Full Text Available Consistent grain yield in drought environment has attracted wide attention due to global climate change. However, the important drought-related traits/genes in crops have been rarely reported. Many near-isogenic lines (NILs of male sterile and fertile Salvia miltiorrhiza have been obtained in our previous work through testcross and backcross in continuous field experiments conducted in 2006–2009. Both segregating sterile and fertile populations were subjected to bulked segregant analysis (BSA and amplified fragment length polymorphism (AFLP with 384 and 170 primer combinations, respectively. One out of 14 AFLP markers (E9/M3246 was identified in treated fertile population as tightly linked to the drought stress gene with a recombination frequency of 6.98% and at a distance of 7.02 cM. One of 15 other markers (E2/M5357 was identified in a treated sterile population that is closely associated with the drought stress gene. It had a recombination frequency of 4.65% and at a distance of 4.66 cM. Interestingly, the E9/M3246 fragment was found to be identical to another AFLP fragment E11/M4208 that was tightly linked to the male sterile gene of S. miltiorrhiza with 95% identity and e-value 4 × 10−93. Blastn analysis suggested that the drought stress gene sequence showed higher identity with nucleotides in Arabidopsis chromosome 1–5.

  18. Characterization of Pseudomonas aeruginosa in Burn Patients Using PCR- Restriction Fragment Length Polymorphism and Random Amplified Polymorphic DNA Analysis

    OpenAIRE

    Abdolaziz Rastegar Lari; Bagher Yakhchali; Parviz Owlia; Hassan Salimi

    2010-01-01

    One of the major opportunistic pathogens in patients with burninjuries is Pseudomonas aeruginosa, which causes severe infectionsin burned patients. The objective of the study was to examinethe molecular epidemiology of P. aeruginosa colonization inthe burn unit of Shahid Motahari Hospital in Tehran, Iran. Restrictionfragment length polymorphism (RFLP) and random amplifiedpolymorphic DNA (RAPD) analysis were employed tostudy 127 clinical and two environmental P. aeruginosa isolatescollected fr...

  19. Physical and genetic mapping of amplified fragment length polymorphisms and the leaf rust resistance Lr3 gene on chromosome 6BL of wheat.

    Science.gov (United States)

    Diéguez, M J; Altieri, E; Ingala, L R; Perera, E; Sacco, F; Naranjo, T

    2006-01-01

    The Argentinian wheat cultivar Sinvalocho MA carries the Lr3 gene for leaf rust resistance on distal chromosome 6BL. In this cultivar, 33 spontaneous susceptible lines were isolated and cytogenetically characterized by C-banding. The analysis revealed deletions on chromosome 6BL in most lines. One line was nulli-6B, two lines were ditelo 6BS, two, three, and ten lines had long terminal deletions of 40, 30, and 20%, respectively, three lines showed very small terminal deletions, and one line had an intercalary deletion of 11%. Physical mapping of 55 amplified fragment length polymorphism (AFLP) markers detected differences between deletions and led to the division of 6BL into seven bins delimited by deletion breakpoints. The most distal bin, with a length smaller than 5% of 6BL, contained 22 AFLP markers and the Lr3 gene. Polymorphism for nine AFLPs between Sinvalocho MA and the rust leaf susceptible cultivar Gamma 6 was used to construct a linkage map of Lr3. This gene is at a genetic distance of 0.9 cM from a group of seven closely linked AFLPs. The location of the gene in a high recombinogenic region indicated a physical distance of approximately 1 Mb to the markers. PMID:16215730

  20. An Analysis on DNA Fingerprints of Thirty Papaya Cultivars (Carica papaya L., Grown in Thailand with the Use of Amplified Fragment Length Polymorphisms Technique

    Directory of Open Access Journals (Sweden)

    Janthasri Ratchadaporn

    2007-01-01

    Full Text Available The experiment was carried out at the Department of Horticulture, Ubon Ratchathani University, Ubon Ratchathani province, Northeast Thailand during June 2002 to May 2003 aims to identify DNA fingerprints of thirty papaya cultivars with the use of Amplified Fragment Length Polymorphisms (AFLP technique. Papaya cultivars were collected from six different research centers in Thailand. Papaya plants of each cultivar were grown under field conditions up to four months then leaf numbers 2 and 3 of each cultivar (counted from top were chosen for DNA extraction and the samples were used for AFLP analysis. Out of 64 random primers being used, 55 pairs gave an increase in DNA bands but only 12 pairs of random primers were randomly chosen for the final analysis of the experiment. The results showed that AFLP markers gave Polymorphic Information Contents (PIC of three ranges i.e., AFLP markers of 235 lied on a PIC range of 0.003-0.05, 47 for a PIC range of 0.15-0.20 and 12 for a PIC range of 0.35-0.40. The results on dendrogram cluster analysis revealed that the thirty papaya cultivars were classified into six groups i.e., (1 Kaeg Dum and Malador (2 Kaeg Nuan (3 Pakchong and Solo (4 Taiwan (5 Co Coa Hai Nan and (6 Sitong. Nevertheless, in spite of the six papaya groups all papaya cultivars were genetically related to each other where diversity among the cultivars was not significantly found.

  1. An analysis on DNA fingerprints of thirty papaya cultivars (Carica papaya L.), grown in Thailand with the use of amplified fragment length polymorphisms technique.

    Science.gov (United States)

    Ratchadaporn, Janthasri; Sureeporn, Katengam; Khumcha, U

    2007-09-15

    The experiment was carried out at the Department of Horticulture, Ubon Ratchathani University, Ubon Ratchathani province, Northeast Thailand during June 2002 to May 2003 aims to identify DNA fingerprints of thirty papaya cultivars with the use of Amplified Fragment Length Polymorphisms (AFLP) technique. Papaya cultivars were collected from six different research centers in Thailand. Papaya plants of each cultivar were grown under field conditions up to four months then leaf numbers 2 and 3 of each cultivar (counted from top) were chosen for DNA extraction and the samples were used for AFLP analysis. Out of 64 random primers being used, 55 pairs gave an increase in DNA bands but only 12 pairs of random primers were randomly chosen for the final analysis of the experiment. The results showed that AFLP markers gave Polymorphic Information Contents (PIC) of three ranges i.e., AFLP markers of 235 lied on a PIC range of 0.003-0.05, 47 for a PIC range of 0.15-0.20 and 12 for a PIC range of 0.35-0.40. The results on dendrogram cluster analysis revealed that the thirty papaya cultivars were classified into six groups i.e., (1) Kaeg Dum and Malador (2) Kaeg Nuan (3) Pakchong and Solo (4) Taiwan (5) Co Coa Hai Nan and (6) Sitong. Nevertheless, in spite of the six papaya groups all papaya cultivars were genetically related to each other where diversity among the cultivars was not significantly found. PMID:19090101

  2. Genetic Mapping of Laminaria japonica and L. longissima Using Amplified Fragment Length Polymorphism Markers in a "Two-Way Pseudo-Testcross" Strategy

    Institute of Scientific and Technical Information of China (English)

    Yuhui Li; Yingxia Yang; Jidong Liu; Xiuliang Wang; Tianxiang Gao; Delin Duan

    2007-01-01

    With a "two-way pseudo-testcross" mapping strategy, we applied the amplified fragment length polymorphism (AFLP) markers to construct two moderate density genetic linkage maps for Laminaria. The linkage maps were generated from the 60 progenies of the F1 cross family (Laminaria longissima Aresch. x L. japonica Miyabe) with twenty pairs of primer combinations. Of the 333 polymorphic loci scored in 60 progenies, 173 segregated in a 1:1ratio, corresponding to DNA polymorphisms heterozygous in a single parent, and the other 58 loci existing in both parents followed a 3:1 Mendelian segregation ratio. Among the loci with 1:1 segregating ratios, 79 loci were ordered in 14 linkage groups (648.6 cM) of the paternal map, and 72 loci were ordered in 14 linkage groups (601.9 cM) of the maternal map. The average density of loci was approximately 1 per 8 cM. To investigate the homologies between two parental maps, we used 58 loci segregated 3:1 for further analysis, and deduced one homologous linkage group. The linkage data developed in these maps will be useful for detecting loci-controlling commercially important traits for Laminaria.

  3. Examining the genetic variation of reference microbial cultures used within food and environmental laboratories using fluorescent amplified fragment length polymorphism analysis.

    Science.gov (United States)

    Cross, Lisa Jane; Russell, Julie Elizabeth; Desai, Meeta

    2011-08-01

    Fluorescent amplified fragment length polymorphism (FAFLP) analysis was applied to genetically fingerprint 'working culture control strains' used by accredited food microbiology laboratories. A working culture control strain is defined as a subculture from a strain initially obtained from an authenticated source [such as the National Collection of Type Cultures (NCTC)] that is maintained for use with routine testing within the laboratory. Working culture control strains from eight food examination laboratories, representing four bacterial species, were analysed by FAFLP; these were Salmonella Nottingham, Staphylococcus aureus, Listeria monocytogenes and Bacillus cereus. The resultant FAFLP profiles of the eight working culture control strains for each of these species were compared against the appropriate freeze-dried ampoules obtained directly from NCTC. FAFLP results demonstrated that within 50% of working cultures analysed, several laboratories were routinely using working cultures that were genetically different from the original reference NCTC strains. This study highlights the need for laboratories to review the protocols used to process and maintain control strains and working cultures, with a potential view to utilize single-use quality control materials. PMID:21623896

  4. Differential gene expression in response to Papaya ringspot virus infection in Cucumis metuliferus using cDNA-amplified fragment length polymorphism analysis.

    Directory of Open Access Journals (Sweden)

    Yu-Tsung Lin

    Full Text Available A better understanding of virus resistance mechanisms can offer more effective strategies to control virus diseases. Papaya ringspot virus (PRSV, Potyviridae, causes severe economical losses in papaya and cucurbit production worldwide. However, no resistance gene against PRSV has been identified to date. This study aimed to identify candidate PRSV resistance genes using cDNA-AFLP analysis and offered an open architecture and transcriptomic method to study those transcripts differentially expressed after virus inoculation. The whole genome expression profile of Cucumis metuliferus inoculated with PRSV was generated using cDNA-amplified fragment length polymorphism (cDNA-AFLP method. Transcript derived fragments (TDFs identified from the resistant line PI 292190 may represent genes involved in the mechanism of PRSV resistance. C. metuliferus susceptible Acc. 2459 and resistant PI 292190 lines were inoculated with PRSV and subsequently total RNA was isolated for cDNA-AFLP analysis. More than 400 TDFs were expressed specifically in resistant line PI 292190. A total of 116 TDFs were cloned and their expression patterns and putative functions in the PRSV-resistance mechanism were further characterized. Subsequently, 28 out of 116 candidates which showed two-fold higher expression levels in resistant PI 292190 than those in susceptible Acc. 2459 after virus inoculation were selected from the reverse northern blot and bioinformatic analysis. Furthermore, the time point expression profiles of these candidates by northern blot analysis suggested that they might play roles in resistance against PRSV and could potentially provide valuable information for controlling PRSV disease in the future.

  5. Differential gene expression in response to Papaya ringspot virus infection in Cucumis metuliferus using cDNA-amplified fragment length polymorphism analysis.

    Science.gov (United States)

    Lin, Yu-Tsung; Jan, Fuh-Jyh; Lin, Chia-Wei; Chung, Chien-Hung; Chen, Jo-Chu; Yeh, Shy-Dong; Ku, Hsin-Mei

    2013-01-01

    A better understanding of virus resistance mechanisms can offer more effective strategies to control virus diseases. Papaya ringspot virus (PRSV), Potyviridae, causes severe economical losses in papaya and cucurbit production worldwide. However, no resistance gene against PRSV has been identified to date. This study aimed to identify candidate PRSV resistance genes using cDNA-AFLP analysis and offered an open architecture and transcriptomic method to study those transcripts differentially expressed after virus inoculation. The whole genome expression profile of Cucumis metuliferus inoculated with PRSV was generated using cDNA-amplified fragment length polymorphism (cDNA-AFLP) method. Transcript derived fragments (TDFs) identified from the resistant line PI 292190 may represent genes involved in the mechanism of PRSV resistance. C. metuliferus susceptible Acc. 2459 and resistant PI 292190 lines were inoculated with PRSV and subsequently total RNA was isolated for cDNA-AFLP analysis. More than 400 TDFs were expressed specifically in resistant line PI 292190. A total of 116 TDFs were cloned and their expression patterns and putative functions in the PRSV-resistance mechanism were further characterized. Subsequently, 28 out of 116 candidates which showed two-fold higher expression levels in resistant PI 292190 than those in susceptible Acc. 2459 after virus inoculation were selected from the reverse northern blot and bioinformatic analysis. Furthermore, the time point expression profiles of these candidates by northern blot analysis suggested that they might play roles in resistance against PRSV and could potentially provide valuable information for controlling PRSV disease in the future. PMID:23874746

  6. Fluorescent amplified fragment length polymorphism (FAFLP genotyping demonstrates the role of biofilm-producing methicillin-resistant periocular Staphylococcus epidermidis strains in postoperative endophthalmitis

    Directory of Open Access Journals (Sweden)

    Hasnain Seyed E

    2006-01-01

    Full Text Available Abstract Background An observational case series was used to study the virulence characteristics and genotypes of paired Staphylococcus epidermidis isolates cultured from intraocular samples and from periocular environment of patients with postcataract surgery endophthalmitis. Methods Eight S. epidermidis isolates were obtained from three patients (2 from patients #1 and 2 and 4 from patient #3 whose vitreous and/or anterior chamber (AC specimens and preoperative lid/conjunctiva samples were culture positive. Cultures were identified by API-Staph phenotypic identification system and genotypically characterized by Fluorescent Amplified Fragment Length Polymorphism (FAFLP and checked for their antimicrobial susceptibility. The isolates were tested for biofilm-production and methicillin-resistance (MR by PCR amplification of icaAB and mecA gene respectively. Results Four out of eight S. epidermidis strains showed multiple drug resistance (MDR. All the eight strains were PCR positive for mecA gene whereas seven out of eight strains were positive for icaAB genes. In all three patients FAFLP typing established vitreous isolates of S. epidermidis strains to be indistinguishable from the strains isolated from the patient's conjunctival swabs. However, from patient number three there was one isolate (1030b from lid swab, which appeared to be nonpathogenic and ancestral having minor but significant differences from other three strains from the same patient. This strain also lacked icaAB gene. In silico analysis indicated possible evolution of other strains from this strain in the patient. Conclusion Methicillin-resistant biofilm positive S. epidermidis strains colonizing the conjunctiva and eyelid were responsible for postoperative endophthalmitis (POE.

  7. Identification of cultured isolates of clinically important yeast species using fluorescent fragment length analysis of the amplified internally transcribed rRNA spacer 2 region

    Directory of Open Access Journals (Sweden)

    Muylaert An

    2002-07-01

    Full Text Available Abstract Background The number of patients with yeast infection has increased during the last years. Also the variety of species of clinical importance has increased. Correct species identification is often important for efficient therapy, but is currently mostly based on phenotypic features and is sometimes time-consuming and depends largely on the expertise of technicians. Therefore, we evaluated the feasibility of PCR-based amplification of the internally transcribed spacer region 2 (ITS2, followed by fragment size analysis on the ABI Prism 310 for the identification of clinically important yeasts. Results A rapid DNA-extraction method, based on simple boiling-freezing was introduced. Of the 26 species tested, 22 could be identified unambiguously by scoring the length of the ITS2-region. No distinction could be made between the species Trichosporon asteroides and T. inkin or between T. mucoides and T. ovoides. The two varieties of Cryptococcus neoformans (var. neoformans and var. gattii could be differentiated from each other due to a one bp length difference of the ITS2 fragment. The three Cryptococcus laurentii isolates were split into two groups according to their ITS2-fragment lengths, in correspondence with the phylogenetic groups described previously. Since the obtained fragment lengths compare well to those described previously and could be exchanged between two laboratories, an internationally usable library of ITS2 fragment lengths can be constructed. Conclusions The existing ITS2 size based library enables identification of most of the clinically important yeast species within 6 hours starting from a single colony and can be easily updated when new species are described. Data can be exchanged between laboratories.

  8. Construction of a high-density genetic map based on large-scale markers developed by specific length amplified fragment sequencing (SLAF-seq) and its application to QTL analysis for isoflavone content in Glycine max

    OpenAIRE

    Li, Bin; Tian, Ling; Zhang, Jingying; Huang, Long; Han, Fenxia; Yan, Shurong; Wang, Lianzheng; Zheng, Hongkun; Sun, Junming

    2014-01-01

    Background Quantitative trait locus (QTL) mapping is an efficient approach to discover the genetic architecture underlying complex quantitative traits. However, the low density of molecular markers in genetic maps has limited the efficiency and accuracy of QTL mapping. In this study, specific length amplified fragment sequencing (SLAF-seq), a new high-throughput strategy for large-scale SNP discovery and genotyping based on next generation sequencing (NGS), was employed to construct a high-de...

  9. Development of fluorescent amplified fragment length polymorphism for Streptococcus suis%猪链球菌荧光DNA扩增片段长度多态性检测方法的建立

    Institute of Scientific and Technical Information of China (English)

    王楷成; Linda van der Graaf; 陆承平; 黄保续; 范伟兴

    2012-01-01

    The fluorescent amplified fragment length for Streptococcus suis was developed using 2 pairs of primers.51 to 98 fragments of highly polymorphic products were obtained by 2 pairs of primers in 12 Streptococcus suis isolates.The fluorescent amplified fragment length technique can be used to detect the DNA polymorphism of Streptococcus suis.Different serotypes or different isolates of the same serotype in Streptococcus suis can be distinguished by the method.It is available in identification or tracking for Streptococcus suis strains.%利用荧光标记技术,采用2对引物初步建立检测猪链球菌荧光DNA扩增片段长度多态性方法,结果表明12株猪链球菌扩增的多态性位点数从51~98条不等,该方法能够检测猪链球菌的多态性,区分不同血清型以及同一血清型不同特性的菌株,可用于菌株鉴定及流行病学研究中细菌源的追踪。

  10. Amplified fragment length polymorphism of clinical and environmental Vibrio cholerae from a freshwater environment in a cholera-endemic area, India

    Directory of Open Access Journals (Sweden)

    Sharma Naresh C

    2011-09-01

    Full Text Available Abstract Background The region around Chandigarh in India has witnessed a resurgence of cholera. However, isolation of V. cholerae O1 from the environment is infrequent. Therefore, to study whether environmental nonO1-nonO139 isolates, which are native to the aquatic ecosystem, act as precursors for pathogenic O1 strains, their virulence potential and evolutionary relatedness was checked. Methods V. cholerae was isolated from clinical cases of cholera and from water and plankton samples collected from freshwater bodies and cholera-affected areas. PCR analysis for the ctxA, ctxB, tcpA, toxT and toxR genes and AFLP with six primer combinations was performed on 52 isolates (13 clinical, 34 environmental and 5 reference strains. Results All clinical and 3 environmental isolates belonged to serogroup O1 and remaining 31 environmental V. cholerae were nonO1-nonO139. Serogroup O1 isolates were ctxA, tcpA (ElTor, ctxB (Classical, toxR and toxT positive. NonO1-nonO139 isolates possessed toxR, but lacked ctxA and ctxB; only one isolate was positive for toxT and tcpA. Using AFLP, 2.08% of the V. cholerae genome was interrogated. Dendrogram analysis showed one large heterogeneous clade (n = 41, with two compact and distinct subclades (1a and 1b, and six small mono-phyletic groups. Although V. cholerae O1 isolates formed a distinct compact subclade, they were not clonal. A clinical O1 strain clustered with the nonO1-nonO139 isolates; one strain exhibited 70% similarity to the Classical control strain, and all O1 strains possessed an ElTor variant-specific fragment identified with primer ECMT. Few nonO1-nonO139 isolates from widely separated geographical locations intermingled together. Three environmental O1 isolates exhibited similar profiles to clinical O1 isolates. Conclusion In a unique study from freshwater environs of a cholera-endemic area in India over a narrow time frame, environmental V. cholerae population was found to be highly heterogeneous

  11. Intestinal carriage of Campylobacter jejuni and Campylobacter coli among cattle from South-western Norway and comparative genotyping of bovine and human isolates by amplified-fragment length polymorphism

    Directory of Open Access Journals (Sweden)

    Vardund T

    2006-06-01

    Full Text Available Abstract In a survey conducted in 1999–2001, the carriage of thermotolerant Campylobacters in cattle was investigated, and the genetic diversity of C. jejuni within one herd was examined and compared with human isolates. C. jejuni, C. coli and other thermotolerant Campylobacter spp. were isolated from intestinal contents from 26%, 3% and 2% of 804 cattle, respectively. The carriage rate was higher in calves (46% than in adults (29%. Twenty-nine C. jejuni isolates from one herd and 31 human isolates from the study area were genotyped with amplified-fragment length polymorphism (AFLP. Eighty-three % of the bovine isolates fell into three distinct clusters with 95–100% similarity, persistent in the herd for 5–10 months. Among human isolates, 58% showed >90% similarity with bovine isolates. The results show that cattle are a significant and stable reservoir for C. jejuni in the study area. Transmission between individuals within the herd may be sufficient to maintain a steady C. jejuni population independent of environmental influx. The results of this study have provided new information on C. jejuni and C. coli transmission, and also on the carriage in cattle, genotypes stability and similarity between bovine and human isolates.

  12. Evidence of genotypic diversity among Candida auris isolates by multilocus sequence typing, matrix-assisted laser desorption ionization time-of-flight mass spectrometry and amplified fragment length polymorphism.

    Science.gov (United States)

    Prakash, A; Sharma, C; Singh, A; Kumar Singh, P; Kumar, A; Hagen, F; Govender, N P; Colombo, A L; Meis, J F; Chowdhary, A

    2016-03-01

    Candida auris is a multidrug-resistant nosocomial bloodstream pathogen that has been reported from Asian countries and South Africa. Herein, we studied the population structure and genetic relatedness among 104 global C. auris isolates from India, South Africa and Brazil using multilocus sequence typing (MLST), amplified fragment length polymorphism (AFLP) fingerprinting and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). RPB1, RPB2 and internal transcribed spacer (ITS) and D1/D2 regions of the ribosomal DNA were sequenced for MLST. Further, genetic variation and proteomic assessment was carried out using AFLP and MALDI-TOF MS, respectively. Both MLST and AFLP typing clearly demarcated two major clusters comprising Indian and Brazilian isolates. However, the South African isolates were randomly distributed, suggesting different genotypes. MALDI-TOF MS spectral profiling also revealed evidence of geographical clustering but did not correlate fully with the genotyping methods. Notably, overall the population structure of C. auris showed evidence of geographical clustering by all the three techniques analysed. Antifungal susceptibility testing by the CLSI microbroth dilution method revealed that fluconazole had limited activity against 87% of isolates (MIC90, 64 mg/L). Also, MIC90 of AMB was 4 mg/L. Candida auris is emerging as an important yeast pathogen globally and requires reproducible laboratory methods for identification and typing. Evaluation of MALDI-TOF MS as a typing method for this yeast is warranted. PMID:26548511

  13. Variable lipoprotein haemagglutinin (vlhA) gene sequence typing of mainly Dutch Mycoplasma synoviae isolates: comparison with vlhA sequences from Genbank and with amplified fragment length polymorphism analysis.

    Science.gov (United States)

    Dijkman, R; Feberwee, A; Landman, W J M

    2014-01-01

    Molecular typing techniques with sufficient discriminatory power are required to better understand the transmission of Mycoplasma synoviae, a poultry pathogen with increasing clinical and economic relevance. A promising molecular technique is polymerase chain reaction and subsequent sequencing based on the conserved 5' region of the M. synoviae variable lipoprotein and haemagglutinin (vlhA) gene. This technique was used for genotyping 27 mainly Dutch M. synoviae isolates from different organs of various categories of poultry housed on different farms and collected during a period of 10 years. The obtained vlhA sequences were compared with those of M. synoviae strains from Genbank and data obtained by amplified fragment length polymorphism (AFLP). Grouping based on 100% similarity revealed nine genotypes. Some isolates had identical vlhA gene sequences although they originated from different geographical areas, different years and organs. AFLP analysis results largely confirmed the results obtained by vlhA sequence typing. Our findings raise concern regarding the discriminatory power of these techniques for its use in molecular epidemiology of Dutch M. synoviae isolates and for the differentiation between M. synoviae vaccine strains and field isolates, and indicate that molecular typing based on additional markers should be considered. PMID:25189763

  14. Molecular epidemiology and in-vitro antifungal susceptibility of Aspergillus terreus species complex isolates in Delhi, India: evidence of genetic diversity by amplified fragment length polymorphism and microsatellite typing.

    Directory of Open Access Journals (Sweden)

    Shallu Kathuria

    Full Text Available Aspergillus terreus is emerging as an etiologic agent of invasive aspergillosis in immunocompromised individuals in several medical centers in the world. Infections due to A. terreus are of concern due to its resistance to amphotericin B, in vivo and in vitro, resulting in poor response to antifungal therapy and high mortality. Herein we examined a large collection of molecularly characterized, geographically diverse A. terreus isolates (n = 140 from clinical and environmental sources in India for the occurrence of cryptic A. terreus species. The population structure of the Indian A. terreus isolates and their association with those outside India was determined using microsatellite based typing (STR technique and Amplified Fragment Length Polymorphism analysis (AFLP. Additionally, in vitro antifungal susceptibility of A. terreus isolates was determined against 7 antifungals. Sequence analyses of the calmodulin locus identified the recently described cryptic species A. hortai, comprising 1.4% of Aspergillus section Terrei isolates cultured from cases of aspergilloma and probable invasive aspergillosis not reported previously. All the nine markers used for STR typing of A. terreus species complex proved to be highly polymorphic. The presence of high genetic diversity revealing 75 distinct genotypes among 101 Indian A. terreus isolates was similar to the marked heterogeneity noticed in the 47 global A. terreus population exhibiting 38 unique genotypes mainly among isolates from North America and Europe. Also, AFLP analysis showed distinct banding patterns for genotypically diverse A. terreus isolates. Furthermore, no correlation between a particular genotype and amphotericin B susceptibility was observed. Overall, 8% of the A. terreus isolates exhibited low MICs of amphotericin B. All the echinocandins and azoles (voriconazole, posaconazole and isavuconazole demonstrated high potency against all the isolates. The study emphasizes the need of

  15. Use of single-enzyme amplified fragment length polymorphism for typing Clostridium perfringens isolated from diarrheic piglets Uso do polimorfismo do comprimento de fragmentos amplificados para tipagem de Clostridium perfringens isolados de suínos com diarréia

    OpenAIRE

    Luciane Tieko Shinya; Maria Regina Baccaro; Andrea Micke Moreno

    2006-01-01

    Clostridium perfringens is an important pathogen in human and veterinary medicine. In swine, the agent is responsible for necrotic enteritis and enterotoxemia characterized by diarrhea, weight loss, delayed development and, in some cases, death. In the present study amplified fragment length polymorphism analyses (AFLP) was used to characterize 54 C. perfringens strains isolated from swine presenting diarrhea. Analysis of the results showed 29 distinct profiles with discriminatory index equal...

  16. AFLP (Amplified Fragment Length Polymorphism:増幅断片長多型)解析による3倍性ギンブナ(Carassius auratus langsdorfi)に特徴的なゲノムマーカーの探索

    OpenAIRE

    高瀬, 有加里; 藤谷, 英男; 村上, 賢; タカセ, ユカリ; フジタニ, ヒデオ; ムラカミ, マサル; Yukari, TAKASE; Hideo, Fujitani; Masaru, MURAKAMI

    2007-01-01

    The Japanese silver crucian carp (so-called ginbuna, Carassius auratus langsdrofi) has two reproduction systems; one is a sexual reproduction practiced by diploid individuals and the other is gynogenetic reproduction by triploid individuals. In this study, AFLP (Amplified Fragment Length Polymorphism) analysis was carried out to isolate and characterize genomic DNA markers for triploid ginbuna, as a step toward revealing the genomic makeup and origin of triploid ginbuna. Two valuable DNA mark...

  17. Identification of beef using restriction fragment length polymorphism–

    Directory of Open Access Journals (Sweden)

    R. A. Al-Sanjary

    2009-01-01

    Full Text Available To differentiate the beef from other types of meat consumed by human, DNA markers based on polymerase chain reaction restriction fragment length polymorphism technique is performed by using universal primers designed on mitochondrial cytochrome b gene to obtain amplified band 359 bp, then digested with some of restriction enzymes like Tru91, RsaI, Hinf I, Hae III, Alu I, Taq I, Mob I. The result revealed that, the Hinf I enzyme produce three bands 198, 117, 44 bp and the Hae III enzyme revealed two band 285, 74 bp, the Alu I enzyme also produced two band but the molecular weight are 190, 169 bp. The other enzymes did not reveal any digestion of the amplified bands and this result is a characteristic unique to beef compared with other types of meat when using same enzymes.

  18. Semiconductor optical amplifier length effects on gain dynamics

    International Nuclear Information System (INIS)

    We study theoretically semiconductor optical amplifier (SOA) length effects on gain dynamics when a short saturating pulse (pump) is either co- or counter-propagative with the probe. More specifically, we focus our attention on SOA recovery dynamics and gain overshoot. Analysis is also given when the input probe power and input pump energy are increased for different SOA lengths

  19. Community Structure of Denitrifiers, Bacteria, and Archaea along Redox Gradients in Pacific Northwest Marine Sediments by Terminal Restriction Fragment Length Polymorphism Analysis of Amplified Nitrite Reductase (nirS) and 16S rRNA Genes

    OpenAIRE

    Braker, Gesche; Ayala-del-Río, Héctor L.; Devol, Allan H.; Fesefeldt, Andreas; Tiedje, James M.

    2001-01-01

    Steep vertical gradients of oxidants (O2 and NO3−) in Puget Sound and Washington continental margin sediments indicate that aerobic respiration and denitrification occur within the top few millimeters to centimeters. To systematically explore the underlying communities of denitrifiers, Bacteria, and Archaea along redox gradients at distant geographic locations, nitrite reductase (nirS) genes and bacterial and archaeal 16S rRNA genes (rDNAs) were PCR amplified and analyzed by terminal restrict...

  20. An efficient method of constructing homologous recom binant baculovirus with PCR-amplified fragments

    Institute of Scientific and Technical Information of China (English)

    HOU; Songwang; (侯松旺); CHEN; Xinwen; (陈新文); WANG; Hanzhong; (王汉中); HU; Zhihong; (胡志红)

    2003-01-01

    This paper describes a rapid method of constructing homologous recombinant baculovirus in E. coli with PCR-amplified fragments. By using this method, the traditional steps of constructing transfer vector are omitted. The method is based on phage λ red system which can promote the recombination between the homologous fragments with the length above 36 bp. Taking HaSNPV as an example, this paper describes the rapid recombination process by using chloramphenicol resistance gene (CmR) to replace orf135 in HaSNPV genome. A pair of primers with length of 60 bp was synthesized, in which 40 bp was homologous to the each end sequence of orf135, and the rest 20 bp was homologous to the each end sequence of CmR. By using these primers, a linear fragment containing the complete CmR gene between 40 bp of homologous arms of orf135 was generated by PCR with the plasmid pKD3 which contains CmR as the template. By transforming the linear fragment into the E. coli containing the bacterial artificial chromosome of HaSNPV and with the help of a plasmid expressing λ recombinase, the recombinants on which the homologue replacement had taken place were selected by chloramphenicol resistance. This method greatly shortens the process of constructing recombinant baculovirus since the process was performed in E. coli and does not need to construct transfer vectors. It can be further used for gene replacement and gene deletion of other large viral genomes.

  1. Population structure of Salmonella investigated by amplified fragment length polymorphism

    DEFF Research Database (Denmark)

    Torpdahl, M.; Ahrens, Peter

    2004-01-01

    whereas others are highly divergent. Conclusions: AFLP clearly clustered strains representing the subgroups of Salmonella together with high bootstrap values and the serotypes of subspecies enterica were divided into polyphyletic or monophyletic types corresponding well with multilocus enzyme...

  2. Optimisation and evaluation of restriction fragment length polimorfism method for apolipoprotein E

    Directory of Open Access Journals (Sweden)

    Drljević Nevena

    2014-01-01

    Full Text Available Introduction. Apolipoprotein E gene polymorphism is characterized by the presence of three common alleles, e2, e3 and e4, which encode three isoforms of apolipoprotein E in plasma E2, E3 and E4. Genetic polymorphisms of apolipoprotein E gene are predictive markers for the development of numerous disorders of lipid metabolism, already proven in a large number of clinical trials. This study was aimed at assessing the success rate of restriction fragment length polymorphism method for the detections of genes coding for isoenzymes E2, E3 and E4. Material and Methods. Deoxyribonucleic acid, used in this study, was extracted from blood by standard procedure using chloroform and phenol. The polymerase chain reaction method was used to amplify the coding sequence of fourth exon of the apolipoprotein E gene. Amplification products were digested with HhaI. The fragments obtained were separated by electrophoresis and visualized with ultraviolet light. Results. Our results showed that the restriction fragment length polymorphism method is optimal for detection of apolipoprotein E polymorphisms. The restriction enzyme HhaI achieved the cleavage of the gene on the specific loci, directly depend of presence or absence of mutations at positions 112 and 158, of different alleles. Conclusion. This method enables simple, rapid and efficient analysis of restriction fragment length polymorphisms, directly determining the patient’s genotype.

  3. Comparison of seven techniques for typing international epidemic strains of Clostridium difficile: restriction endonuclease analysis, pulsed-field gel electrophoresis, PCR-ribotyping, multilocus sequence typing, multilocus variable-number tandem-repeat analysis, amplified fragment length polymorphism, and surface layer protein A gene sequence typing.

    Science.gov (United States)

    Killgore, George; Thompson, Angela; Johnson, Stuart; Brazier, Jon; Kuijper, Ed; Pepin, Jacques; Frost, Eric H; Savelkoul, Paul; Nicholson, Brad; van den Berg, Renate J; Kato, Haru; Sambol, Susan P; Zukowski, Walter; Woods, Christopher; Limbago, Brandi; Gerding, Dale N; McDonald, L Clifford

    2008-02-01

    Using 42 isolates contributed by laboratories in Canada, The Netherlands, the United Kingdom, and the United States, we compared the results of analyses done with seven Clostridium difficile typing techniques: multilocus variable-number tandem-repeat analysis (MLVA), amplified fragment length polymorphism (AFLP), surface layer protein A gene sequence typing (slpAST), PCR-ribotyping, restriction endonuclease analysis (REA), multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). We assessed the discriminating ability and typeability of each technique as well as the agreement among techniques in grouping isolates by allele profile A (AP-A) through AP-F, which are defined by toxinotype, the presence of the binary toxin gene, and deletion in the tcdC gene. We found that all isolates were typeable by all techniques and that discrimination index scores for the techniques tested ranged from 0.964 to 0.631 in the following order: MLVA, REA, PFGE, slpAST, PCR-ribotyping, MLST, and AFLP. All the techniques were able to distinguish the current epidemic strain of C. difficile (BI/027/NAP1) from other strains. All of the techniques showed multiple types for AP-A (toxinotype 0, binary toxin negative, and no tcdC gene deletion). REA, slpAST, MLST, and PCR-ribotyping all included AP-B (toxinotype III, binary toxin positive, and an 18-bp deletion in tcdC) in a single group that excluded other APs. PFGE, AFLP, and MLVA grouped two, one, and two different non-AP-B isolates, respectively, with their AP-B isolates. All techniques appear to be capable of detecting outbreak strains, but only REA and MLVA showed sufficient discrimination to distinguish strains from different outbreaks. PMID:18039796

  4. Identificación de Cultivares y Líneas de Mejoramiento de Arroz de Chile Mediante Amplificación de Fragmentos Polimórficos (AFLP Identification of Chilean Rice Cultivars And Breeding Lines by Means of Amplified Fragment Length Polymorphism (AFLP

    Directory of Open Access Journals (Sweden)

    Carlos Aguirre

    2005-12-01

    Full Text Available Doce cultivares y líneas de arroz (Oryza sativa L. desarrollados por el programa de fitomejoramiento del Instituto de Investigaciones Agropecuarias (INIA, Centro Regional de Investigación Quilamapu, fueron caracterizados genéticamente mediante amplificación de fragmentos polimórficos (AFLP. De 21 combinaciones ensayadas, sólo 16 fueron informativas, generando un total de 667 amplicones, 94 de ellos polimórficos (14,4%, con un rango entre 9 y 33% de polimorfismo por combinación. Esto indica que el material manejado por el programa de INIA presenta un bajo nivel de diversidad genética comparado tanto con germoplasma silvestre de la especie como con aquel usado por otros programas de fitomejoramiento de la especie. Los amplicones polimórficos detectados se usaron para preparar un dendrograma de distancias genéticas, detectándose cuatro grupos diferenciablesque sólo coinciden parcialmente con la información disponible de sus pedigrís. A pesar de la baja diversidad genética detectada, se determinó que con el uso de tres combinaciones de partidores de AFLP+3 (PE1G/PM1I, PE1H/PM1A y PE1G/PM1H es posible discriminar entre los cultivares estudiados.Twelve rice (Oryza sativa L. cultivars and breeding lines developed by the Rice Breeding Program at the National Institute of Agriculture Research (INIA,Quilamapu Regional ResearchCenter, were genetically characterized by amplified fragment length polymorphism (AFLP. Sixteen of 21 primer combinations evaluated were informative, generating a total of 667 amplicons, 94 of them polymorphic (14.4%, with a range between 9 to 33% of polymorphism per primer combination. This indicates that the material handled by the breeding program at INIA has low genetic diversity in comparison to wild germplasm of the species, or even compared to the material managed by other rice breeding programs. The detected polymorphic amplicons were used to prepare a dendrogram of the genetic distances, detecting four

  5. Restriction Fragment Length Polymorphism Analysis of Ribosomal DNA Intergenic Regions Is Useful for Differentiating Strains of Trichophyton mentagrophytes

    OpenAIRE

    Mochizuki, Takashi; Ishizaki, Hiroshi; Barton, Richard C.; Moore, Mary K.; Jackson, Colin J.; Kelly, Steven L.; Evans, E. Glyn V.

    2003-01-01

    Twenty isolates of Tricophyton mentagrophytes var. mentagrophytes and 47 isolates of T. mentagrophytes var. interdigitale, identified by morphological characteristics, were screened by restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified internal transcribed spacer (ITS) region of ribosomal DNA (rDNA). Sixty isolates (14 of 20 T. mentagrophytes var. mentagrophytes isolates and 46 of 47 T. mentagrophytes var. interdigitale isolates) shared an identical ITS RFLP profile...

  6. Differentiation of Neisseria gonorrhoeae strains by polymerase chain reaction and restriction fragment length polymorphism of outer membrane protein IB genes.

    OpenAIRE

    Lau, Q C; Chow, V T; Poh, C. L.

    1995-01-01

    OBJECTIVES--To employ polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis for the rapid differentiation of Neisseria gonorrhoeae protein IB (PIB) isolates and to compare its usefulness with the widely accepted auxotype/serovar classification scheme. METHODS--The outer membrane protein IB genes of 47 gonococcal isolates belonging to 10 different serovars were amplified by PCR. The approximately 1 kb DNA products were then digested separately with restri...

  7. Use of single-enzyme amplified fragment length polymorphism for typing Clostridium perfringens isolated from diarrheic piglets Uso do polimorfismo do comprimento de fragmentos amplificados para tipagem de Clostridium perfringens isolados de suínos com diarréia

    Directory of Open Access Journals (Sweden)

    Luciane Tieko Shinya

    2006-09-01

    Full Text Available Clostridium perfringens is an important pathogen in human and veterinary medicine. In swine, the agent is responsible for necrotic enteritis and enterotoxemia characterized by diarrhea, weight loss, delayed development and, in some cases, death. In the present study amplified fragment length polymorphism analyses (AFLP was used to characterize 54 C. perfringens strains isolated from swine presenting diarrhea. Analysis of the results showed 29 distinct profiles with discriminatory index equal to 0.97. Partial correlation between the origin of the isolates and groups was drawn, and correlation was possible in only 18.5% of the samples. Characterization of the strains in biotypes (A, B, C, D and E, production of beta-2 toxin and enterotoxin were performed by means of the polymerase chain reaction (PCR. Biotypes A, C and D were observed among the strains analyzed. All samples were positive for presence of the gene encoding beta-2 toxin and negative for the gene encoding enterotoxin. AFLP have shown to be a simple, fast, low cost method with high discriminative power and good reproducibility, presenting a great potential in epidemiological studies involving C. perfringens strains of animal origin.Clostridium perfringens é um importante agente infeccioso em medicina veterinária e humana. Em suínos, o agente é responsável pela enterite necrótica e enterotoxemia, caracterizadas por diarréia, perda de peso, atraso no desenvolvimento e morte. No presente estudo foi utilizado o polimorfismo do comprimento de fragmentos amplificados (AFLP, para caracterizar 54 isolados de C. perfringens obtidos de suínos com diarréia. A análise dos resultados do AFLP demonstrou 29 perfis distintos com índice discriminatório igual a 0,97. A correlação entre a origem dos isolados e os agrupamentos obtidos foi parcial, sendo apenas possível a correlação total de 18,5% das amostras estudadas. A caracterização das cepas em biotipos (A, B, C, D e E, produ

  8. Characterisation of Toxoplasma gondii isolates using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) of the non-coding Toxoplasma gondii (TGR)-gene sequences

    DEFF Research Database (Denmark)

    Høgdall, Estrid; Vuust, Jens; Lind, Peter;

    2000-01-01

    of using TGR gene variants as markers to distinguish among T. gondii isolates from different animals and different geographical sources. Based on the band patterns obtained by restriction fragment length polymorphism (RFLP) analysis of the polymerase chain reaction (PCR) amplified TGR sequences, the...

  9. Non PCR-amplified Transcripts and AFLP fragments as reduced representations of the quail genome for 454 Titanium sequencing

    Directory of Open Access Journals (Sweden)

    Leterrier Christine

    2010-07-01

    Full Text Available Abstract Background SNP (Single Nucleotide Polymorphism discovery is now routinely performed using high-throughput sequencing of reduced representation libraries. Our objective was to adapt 454 GS FLX based sequencing methodologies in order to obtain the largest possible dataset from two reduced representations libraries, produced by AFLP (Amplified Fragment Length Polymorphism for genomic DNA, and EST (Expressed Sequence Tag for the transcribed fraction of the genome. Findings The expressed fraction was obtained by preparing cDNA libraries without PCR amplification from quail embryo and brain. To optimize the information content for SNP analyses, libraries were prepared from individuals selected in three quail lines and each individual in the AFLP library was tagged. Sequencing runs produced 399,189 sequence reads from cDNA and 373,484 from genomic fragments, covering close to 250 Mb of sequence in total. Conclusions Both methods used to obtain reduced representations for high-throughput sequencing were successful after several improvements. The protocols may be used for several sequencing applications, such as de novo sequencing, tagged PCR fragments or long fragment sequencing of cDNA.

  10. Fragments of bounded arithmetic and the lengths of proofs

    Czech Academy of Sciences Publication Activity Database

    Pudlák, Pavel

    2008-01-01

    Roč. 73, č. 4 (2008), s. 1389-1406. ISSN 0022-4812 R&D Projects: GA AV ČR IAA1019401 Institutional research plan: CEZ:AV0Z10190503 Keywords : bounded arithmetic * length proofs * Herbrand´s theorem Subject RIV: BA - General Mathematics Impact factor: 0.439, year: 2008

  11. Changes in Mammalian Body Length over 175 Years—Adaptations to a Fragmented Landscape?

    Directory of Open Access Journals (Sweden)

    Per Moestrup Jensen

    2003-12-01

    Full Text Available The potential consequences of anthropogenic habitat fragmentation on species diversity and extinction have drawn considerable attention in recent decades. In many cases, traditional island biogeography theory has been applied to explain the observed patterns. Here, we propose that habitat fragmentation as a selective force can be traced in mammalian body length changes. By exploring historical sources, we are able to show that the body length of Danish mammals has altered over a period of 175 years, possibly in response to increasing habitat fragmentation. The rate of body length change was generally lowest in medium-sized mammals, and increased with both smaller and larger body mass. Small mammals have generally increased, whereas large mammals have decreased in length. In addition to habitat fragmentation, some species may experience other selective forces, such as traffic, and may be trapped in an evolutionary tug-of-war, where the selective forces pull in opposite directions.

  12. Development of deflector cavity and RF amplifier for bunch length detector system

    Science.gov (United States)

    Pandey, H. K.; Bhattacharya, T. K.; Chakrabarti, A.

    2016-02-01

    A minimally-interceptive bunch length detector system is being developed for measurement of longitudinal dimension of the bunch beam from RFQ of the radioactive ion beam (RIB) facility at VECC. This detector system is based on secondary electrons emission produced by the primary ion beam hitting a thin tungsten wire placed in the beam path. In this paper we report the design, development and off line testing results of deflector cavity together with its RF sysytem. The deflector cavity is a capacitive loaded helical type λ/2 resonator driven by RF source of 500 W at 37.8 MHz solid state amplifier, realized by combining two amplifier modules of 300 W each. The measured RF characteristics of the resonator, such as frequency, Q value and shunt impedance have been found to be reasonably good and close to the analytical estimation and results of simulation. The design philosophy and test results of individual components of the amplifier are discussed. The test result upto full power shows a good harmonic separation at the individual module level and this is found to improve further when modules are combined together.The results of high power performance test of the deflector cavity together with amplifier are also reported.

  13. Discrimination among individuals using terminal restriction fragment length polymorphism profiling of bacteria derived from forensic evidence.

    Science.gov (United States)

    Nishi, Eiji; Tashiro, Yukihiro; Sakai, Kenji

    2015-05-01

    DNA typing from forensic evidence is commonly used to identify individuals. However, when the quantity of the forensic evidence is insufficient, successful identification using DNA typing is impossible. Such evidence may also contain DNA from bacteria that occur naturally on the skin. In this study, we aimed to establish a profiling method using terminal restriction fragment length polymorphisms (T-RFLPs) of the amplified bacterial 16S ribosomal RNA (rRNA) gene. First, the extraction and digestion processes were investigated, and the T-RFLP profiling method using the 16S rRNA gene amplicon was optimized. We then used this method to compare the profiles of bacterial flora from the hands of 12 different individuals. We found that the T-RFLP profiles from one person on different days displayed higher similarity than those between individuals. In a principal component analysis (PCA), T-RFLPs from each individual were closely clustered in 11 out of 12 cases. The clusters could be distinguished from each other, even when the samples were collected from different conditions. No major change of the profile was observed after six months except in two cases. When handprints on glass plates were compared, 11 of 12 individuals were assigned to a few clusters including the cluster corresponding to the correct individual. In conclusion, a method for reproducible T-RFLP profiling of bacteria from trace amounts of handprints was established. The profiles were obtained for particular individuals clustered in PCA and were experimentally separable from other individuals in most cases. This technique could provide useful information for narrowing down a suspect in a criminal investigation. PMID:25335807

  14. Restriction Fragment Length Polymorphisms in the Mushrooms Agaricus brunnescens and Agaricus bitorquis

    OpenAIRE

    Castle, Alan J; Horgen, Paul A.; Anderson, James B.

    1987-01-01

    Two Agaricus species, A. brunnescens (a commercial mushroom) and A. bitorquis (a wild, edible species), were examined for restriction fragment length polymorphisms. EcoRI-digested nuclear DNA from isolates of both species were cloned in plasmid vector pUC18. Ten random recombinant clones were used in Southern DNA-DNA hybridizations to probe EcoRI-digested DNA from 11 A. brunnescens isolates (7 commercial, 2 wild type, and 2 homokaryotic) and 7 A. bitorquis isolates. Most cloned fragments were...

  15. Comparison of detection platforms and post-polymerase chain reaction DNA purification methods for use in conjunction with Cleavase fragment length polymorphism analysis.

    Science.gov (United States)

    Sander, T; Olson, S; Hall, J; Siebert, M; Grooms, K; Heisler, L; de Arruda, M; Neri, B

    1999-06-01

    The removal of impurities and contaminants from PCR-amplified fragments is important for mutation detection methods which identify mutations based on shifts in electrophoretic mobility. This is particularly critical for assays and detection methods which use target DNA that is labeled prior to analysis and electrophoretic detection. We examined several procedures for purifying DNA amplified by the polymerase chain reaction (PCR) and their use in conjunction with a novel DNA scanning method, the Cleavase fragment length polymorphism (CFLP)* assay. In this study, a 480 bp DNA fragment, fluorescently labeled on the 5'-end of one strand, was amplified and subjected to various widely used purification procedures, including several commercially available clean-up kits. We demonstrate that visualization of the fluorescent label, as opposed to simple ethidium bromide staining, reveals the presence of considerable levels of labeled, truncated, amplification products. The various procedures were evaluated on the basis of their ability to remove these unwanted DNA fragments as well as on the degree to which they inhibited or promoted the CFLP reaction. Several procedures are recommended for use with CFLP analysis, including isopropanol precipitation, gel excision, and several commercially available spin columns. Concurrently, we evaluated (compared) a number of commonly used visualization platforms, including fluorescence imaging, chemiluminescence, and post-electrophoretic staining, for the ability to detect CFLP pattern changes. The advantages and disadvantages of different methods are discussed and amounts of DNA to be used for CFLP analysis on different detection platforms are recommended. PMID:10380752

  16. Identification of Staphylococcus spp. by PCR-Restriction Fragment Length Polymorphism of gap Gene

    OpenAIRE

    Yugueros, Javier; Temprano, Alejandro; Sánchez, María; Luengo, José María; Naharro, Germán

    2001-01-01

    Oligonucleotide primers specific for the Staphylococcus aureus gap gene were previously designed to identify 12 Staphylococcus spp. by PCR. In the present study, AluI digestion of PCR-generated products rendered distinctive restriction fragment length polymorphism patterns that allowed 24 Staphylococcus spp. to be identified with high specificity.

  17. Single Cystosorus Isolate Production and Restriction Fragment Length Polymorphism Characterization of the Obligate Biotroph Spongospora subterranea f. sp. subterranea.

    Science.gov (United States)

    Qu, Xinshun; Christ, Barbara J

    2006-10-01

    ABSTRACT Spongospora subterranea f. sp. subterranea causes powdery scab in potatoes and is distributed worldwide. Genetic studies of this pathogen have been hampered due, in part, to its obligate parasitism and the lack of molecular markers for this pathogen. In this investigation, a single cystosorus inoculation technique was developed to produce large amounts of S. subterranea f. sp. subterranea plasmodia or zoosporangia in eastern black nightshade (Solanum ptycanthum) roots from which DNA was extracted. Cryopreservation of zoosporangia was used for long-term storage of the isolates. S. subterranea f. sp. subterranea-specific restriction fragment length polymorphism (RFLP) markers were developed from randomly amplified polymorphic DNA (RAPD) fragments. Cystosori of S. subterranea f. sp. subterranea were used for RAPD assays and putative pathogen-specific RAPD fragments were cloned and sequenced. The fragments were screened for specificity by Southern hybridization and subsequent DNA sequence BLAST search. Four polymorphic S. subterranea f. sp. subterranea-specific probes containing repetitive elements, and one containing single copy DNA were identified. These RFLP probes were then used to analyze 24 single cystosorus isolates derived from eight geographic locations in the United States and Canada. Genetic variation was recorded among, but not within, geographic locations. Cluster analysis separated the isolates into two major groups: group I included isolates originating from western North America, with the exception of those from Colorado, and group II included isolates originating from eastern North America and from Colorado. The techniques developed in this study, i.e., production of single cystosorus isolates of S. subterranea f. sp. subterranea and development of RFLP markers for this pathogen, provide methods to further study the genetic structure of S. subterranea f. sp. subterranea. PMID:18943505

  18. Differentiation of Helicobacter pylori isolates by polymerase chain reaction-restriction fragment length polymorphism

    Institute of Scientific and Technical Information of China (English)

    SHI Li; SUN Yong; ZHANG Ya-li; ZHANG Zhen-shu; ZHOU Dian-yuan

    2002-01-01

    Objective: To investigate the association between the diversity of urease gene and urease activity of clinical isolates of Helicobacter pylori (H. pylori). Methods: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of urease gene and rapid urease activity test were used to study the urease activity of different clinical isolates of H. pylori. Results: H. pylori clinical isolates were divided into 4types according to their PCR-RFLP results of urease gene and urease activity. Type I , possessing strong urease activity (0. 11) and presented 1 fragment of 1.7 kb by PCR-RFLP, had close relations with gastric ulcer; type Ⅱ , with the weakest urease activity (0. 07) and 2 fragments (1.3 and 0. 4 kb respectively), was associated with duodenal bulb ulcer; type Ⅱ , with the strongest urease activity (0. 12) and 2 fragments (0. 4and 0. 17 kb) with or without 1 fragment (0. 23 or 0. 37 kb) , was responsible for gastritis; type Ⅳ, with weak urease activity (0. 09) and 2 fragments (1.5 and 0. 2 kb), was shown to be related to both gastric and duodenal bulb ulcers. Conclusion: The diversity of urease gene decides different urease activities of different clinical isolates of H. pylori, hence the different possibilities of pathogenesis due to this bacteria.

  19. Molecular differentiation of Angiostrongylus costaricensis, A. cantonensis, and A. vasorum by polymerase chain reaction- restriction fragment length polymorphism

    Directory of Open Access Journals (Sweden)

    Caldeira Roberta L

    2003-01-01

    Full Text Available Angiostrongylus cantonensis, A. costaricensis, and A. vasorum are etiologic agents of human parasitic diseases. Their identification, at present, is only possible by examining the adult worm after a 40-day period following infection of vertebrate hosts with the third-stage larvae. In order to obtain a diagnostic tool to differentiate larvae and adult worm from the three referred species, polymerase chain reaction-restriction fragment length polymorphism was carried out. The rDNA second internal transcribed spacer (ITS2 and mtDNA cytochrome oxidase I regions were amplified, followed by digestion of fragments with the restriction enzymes RsaI, HapII, AluI, HaeIII, DdeI and ClaI. The enzymes RsaI and ClaI exhibited the most discriminating profiles for the differentiation of the regions COI of mtDNA and ITS2 of rDNA respectively. The methodology using such regions proved to be efficient for the specific differentiation of the three species of Angiostrongylus under study.

  20. Determination of genotypes of hepatitis C virus in Venezuela by restriction fragment length polymorphism.

    OpenAIRE

    Pujol, F. H.; Loureiro, C. L.; Devesa, M; Blitz, L.; Parra, K; Beker, S; Liprandi, F

    1997-01-01

    Hepatitis C virus genotypes in Venezuela were analyzed by restriction fragment length polymorphism in the 5' noncoding region. The absence of BstUI digestion was found to be a useful marker for genotype 2 specimens. From 122 serum samples, 66, 20, and 2.5% were classified as genotypes 1, 2, and 3, respectively; 0.8% were classified as genotype 4; and 10% appeared to be mixed infections.

  1. Analysis of Rumen Microbial Population of Cattle Given Silage and Probiotics Using Terminal Restriction Fragment Length Polymorphism

    Directory of Open Access Journals (Sweden)

    RONI RIDWAN

    2009-12-01

    Full Text Available Rumen ecology is an important observation in evaluating the effectivity of silage and probiotic additives relating to their roles in cattle productivity. The objective of this study was to examine the effects of silage and probiotics on ruminal ecosystems in vivo using a molecular approach. Terminal-restriction fragment-length-polymorphism (T-RFLP analysis was used to detect changes of ecological communities based on 16S-ribosomal deoxyribonucleic acid (16S-rDNA. Two rumen canulated PO cattle were fed several diets i.e.; (R0 basal diet dry matter basis (Pennisetum purpureum 70% and commercial concentrate 30%, (R1 silage (basal diet fermented using Lactobacillus plantarum BTCC570, (R2 silage + probiotics (L. plantarium Str BTCC531, (R3 Basal diet + probiotics (L. plantarium Str BTCC531. Digesta samples were collected 3 h after feeding for pH and T-RFLP analysis. T-RFLP analysis was performed using the 16S-rDNA amplified from each sample. The lengths of the terminal restriction fragments were analysed after digestion with HhaI, HaeIII and MspI. Results showed the effectivenes of silage and probiotics, given together, on the index of Smith and Wilson evenness applied to T-RFLP ecology data (Evar with 0.89±0.04 being the highest. The diversity of rumen microorganisms is influenced by individual differences of each animal. T-RFLP analysis has a potency to be used for comparisons of complex bacterial communities, especially to detect changes in community structure in response to different variables and to show rumen bacteria diversity in the rumen.

  2. Rapid Identification and Differentiation of the Soft Rot Erwinias by 16S-23S Intergenic Transcribed Spacer-PCR and Restriction Fragment Length Polymorphism Analyses

    OpenAIRE

    Toth, I. K.; Avrova, A. O.; Hyman, L. J.

    2001-01-01

    Current identification methods for the soft rot erwinias are both imprecise and time-consuming. We have used the 16S-23S rRNA intergenic transcribed spacer (ITS) to aid in their identification. Analysis by ITS-PCR and ITS-restriction fragment length polymorphism was found to be a simple, precise, and rapid method compared to current molecular and phenotypic techniques. The ITS was amplified from Erwinia and other genera using universal PCR primers. After PCR, the banding patterns generated al...

  3. Fluorescence and amplified spontaneous emission of glass forming compounds containing styryl-4H-pyran-4-ylidene fragment

    Energy Technology Data Exchange (ETDEWEB)

    Vembris, Aivars, E-mail: aivars.vembris@cfi.lu.lv [Institute of Solid State Physics, University of Latvia, 8 Kengaraga Street, Riga LV-1063 (Latvia); Muzikante, Inta [Institute of Solid State Physics, University of Latvia, 8 Kengaraga Street, Riga LV-1063 (Latvia); Karpicz, Renata; Sliauzys, Gytis [Institute of Physics, Center for Physical Sciences and Technology, A. Gostauto 11, LT-01108 Vilnius (Lithuania); Miasojedovas, Arunas; Jursenas, Saulius [Institute of Applied Research, Vilnius University, Sauletekio 9-III, LT-10222 Vilnius (Lithuania); Gulbinas, Vidmantas [Institute of Physics, Center for Physical Sciences and Technology, A. Gostauto 11, LT-01108 Vilnius (Lithuania)

    2012-09-15

    Potential of glassy films of newly synthesised low molecular weight organic molecules for light amplification and lasing applications has been investigated by analysing fluorescence, transient differential absorption and amplified spontaneous emission properties. These non-symmetric and symmetric molecules contain styryl-4H-pyran-4-ylidene fragment with three different electron acceptor groups: dicyanomethylene, barbituric acid, indene-1,3-dione. Fluorescence quantum yields of the investigated compounds in solutions are between 0.32 and 0.54, while they drop down by an order of magnitude in thin solid films. Incorporation of bulky side groups reduced excitonic interactions enabling manifestation of amplified spontaneous emission in the neat films of the investigated derivatives. - Highlights: Black-Right-Pointing-Pointer Bulky substituents attached to DCM dye enable formation of neat glassy films. Black-Right-Pointing-Pointer Investigated dyes show amplified spontaneous emission in neat films. Black-Right-Pointing-Pointer Two electron donor groups negatively influence light amplification.

  4. Fluorescence and amplified spontaneous emission of glass forming compounds containing styryl-4H-pyran-4-ylidene fragment

    International Nuclear Information System (INIS)

    Potential of glassy films of newly synthesised low molecular weight organic molecules for light amplification and lasing applications has been investigated by analysing fluorescence, transient differential absorption and amplified spontaneous emission properties. These non-symmetric and symmetric molecules contain styryl-4H-pyran-4-ylidene fragment with three different electron acceptor groups: dicyanomethylene, barbituric acid, indene-1,3-dione. Fluorescence quantum yields of the investigated compounds in solutions are between 0.32 and 0.54, while they drop down by an order of magnitude in thin solid films. Incorporation of bulky side groups reduced excitonic interactions enabling manifestation of amplified spontaneous emission in the neat films of the investigated derivatives. - Highlights: ► Bulky substituents attached to DCM dye enable formation of neat glassy films. ► Investigated dyes show amplified spontaneous emission in neat films. ► Two electron donor groups negatively influence light amplification.

  5. Genomic diversity among Danish field strains of Mycoplasma hyosynoviae assessed by amplified fragment length polymorphism analysis

    DEFF Research Database (Denmark)

    Kokotovic, Branko; Friis, Niels F.; Nielsen, Elisabeth O.;

    2002-01-01

    ) were concurrently examined for variance in BglII-MfeI and EcoRI-Csp6I-A AFLP markers. A total of 56 different genomic fingerprints having an overall similarity between 77 and 96% were detected. No correlation between AFLP variability and period of isolation or anatomical site of isolation could be...

  6. RESTRICTION FRAGMENT LENGTH POLYMORPHISM ANALYSIS OF PCR-AMPLIFIED NIFH SEQUENCES FROM WETLAND PLANT RHIZOSPHERE COMMUNITIES

    Science.gov (United States)

    We describe a method to assess the community structure of N2-fixing bacteria in the rhizosphere. Total DNA was extracted from Spartina alterniflora and Sesbania macrocarpa root zones by bead-beating and purified by CsCl-EtBr gradient centrifugation. The average DNA yield was 5.5 ...

  7. Detection of Polymorphism at the Insulin Like Growth Factor-I Gene in Mazandaran Native Chicken using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism Method

    Directory of Open Access Journals (Sweden)

    Hossein A. Abbasi

    2011-01-01

    Full Text Available Problem statement: Molecular genetics selection on individual genes is a promising method to genetically improve economically important traits in chickens. The Insulin like Growth Factor-I (IGF1 gene may play important roles in growth of multiple tissues, including muscle cells, cartilage and bone. Approach: In the present study polymorphism of the promoter and 5' untranslated region of IGF-1 gene of Mazandaran native fowls was investigated. In order to evaluate the IGF-1 gene polymorphism we have used a Restriction Fragment Length Polymorphism (RFLP method. Blood samples were collected from randomly chosen 100 Mazandaran native fowls. Genomic DNA was extracted using modified salting-out method and used amplified polymerase chain reaction technique. The promoter and 5' untranslated region of the fowl IGF-1 gene was amplified to produce a 621 bp fragment. The PCR products were electrophoresed on 2.5% agarose gel and stained by etidium bromide. Results: Then, they were digested of amplicon with PstI and revealed two alleles A and B. Data were analyzed using Pop Gene 32 package. In this population, AA, AB, BB genotype have been identified with the 25.88, 50.23, 23.89% frequencies. A and B alleles frequencies were 0.51, 0.49, respectively. The Chi-square (÷2 test was significant and the population was in Hardy-Weinberg equilibrium (pConclusion: The PCR technique amplified a DNA fragment of IGF-1 with 621 bp. The results of the RFLP analysis showed two fragment 257 and 354bp after restriction with enzyme with PstI that identify changes in 5' untranslated region. In according to action modes and importance of IGF-1, its polymorphisms can be related to economical traits such as body weight, muscle cells and bone.

  8. Genetic alterations of hepatocellular carcinoma by random amplified polymorphic DNA analysis and cloning sequencing of tumor differential DNA fragment

    Institute of Scientific and Technical Information of China (English)

    Zhi-Hong Xian; Wen-Ming Cong; Shu-Hui Zhang; Meng-Chao Wu

    2005-01-01

    AIM: To study the genetic alterations and their association with clinicopathological characteristics of hepatocellular carcinoma (HCC), and to find the tumor related DNA fragments.METHODS: DNA isolated from tumors and corresponding noncancerous liver tissues of 56 HCC patients was amplified by random amplified polymorphic DNA (RAPD)with 10 random 10-mer arbitrary primers. The RAPD bands showing obvious differences in tumor tissue DNA corresponding to that of normal tissue were separated,purified, cloned and sequenced. DNA sequences were analyzed and compared with GenBank data.RESULTS: A total of 56 cases of HCC were demonstrated to have genetic alterations, which were detected by at least one primer. The detestability of genetic alterations ranged from 20% to 70% in each case, and 17.9% to 50% in each primer. Serum HBV infection, tumor size,histological grade, tumor capsule, as well as tumor intrahepatic metastasis, might be correlated with genetic alterations on certain primers. A band with a higher intensity of 480 bp or so amplified fragments in tumor DNA relative to normal DNA could be seen in 27 of 56 tumor samples using primer 4. Sequence analysis of these fragments showed 91% homology with Homo sapiens double homeobox protein DUX10 gene.CONCLUSION: Genetic alterations are a frequent event in HCC, and tumor related DNA fragments have been found in this study, which may be associated with hepatocarcinogenesis. RAPD is an effective method for the identification and analysis of genetic alterations in HCC, and may provide new information for further evaluating the molecular mechanism of hepatocarcinogenesis.

  9. Identification of Thiobacillus ferrooxidans strains based on restriction fragment length polymorphism analysis of 16S rDNA.

    Science.gov (United States)

    Kamimura, K; Wakai, S; Sugio, T

    2001-01-01

    The 16S rDNA sequences from ten strains of Thiobacillus ferrooxidans were amplified by PCR. The products were compared by performing restriction fragment length polymorphism (RFLP) analysis with restriction endonucleases Alu I, Hap II, Hha I, and Hae III. The RFLP patterns revealed that T. ferrooxidans could be distinguished from other iron- or sulphur-oxidizing bacteria such as T. thiooxidans NB1-3, T. caldus GO-1, Leptospirillum ferrooxidans and the marine iron-oxidizing bacterium strain KU2-11. The RFLP patterns obtained with Alu I, Hap II, and Hae III were the same for nine strains of T. ferrooxidans except for strain ATCC 13661. The RFLP patterns for strains NASF-1 and ATCC 13661 with Hha I were distinct from those for other T. ferrooxidans strains. The 16S rDNA sequence of T. ferrooxidans NASF-1 possessed an additional restriction site for Hha I. These results show that iron-oxidizing bacteria isolated from natural environments were rapidly identified as T. ferrooxidans by the method combining RFLP analysis with physiological analysis. PMID:11414499

  10. Preliminary characterization of microbial communities in high altitude wetlands of northwestern Argentina by determining terminal restriction fragment length polymorphisms.

    Science.gov (United States)

    Ferrero, Marcela; Farías, María E; Siñeriz, Faustino

    2004-01-01

    Laguna de Pozuelos is an extensive wetland in Morthwestern Argentina at 3,600 m above sea level in the Argentinean Andes. The principal lake, placed in the central depression of endorheic basin, is rich in minerals like Cu, As, Fe, etc. It collects water from underground courses and from two main tributaries, namely Santa Catalina River to the north and Cincel River to the south. Following the dry and rainy seasons, the surface of the lake is subject to an annual contraction-expansion cycle, with increasing of salinity during evaporation period. Prokaryotes inhabitants these particular environments have been not described and a few of such places have been surveyed for microbial diversity studies. To systematically explore the underlying communities of Bacteria from the water lake of Laguna de Pozuelos wetland and Cincel River, bacterial 16S rRNA genes (rDNAs) were PCR amplified and analyzed by terminal restriction fragment length polymorphism (T-RFLP) analysis. Analysis of the microbial community with T-RFLP identified a minimum of 19 operational taxonomic units (OTU). T-RF patterns derived from multiple-enzyme digestion with RsaI, HaeIII and HhaI were analyzed in order to provide a preliminary picture of the relative diversity of this complex microbial community. By the combined use of the three restriction endonucleases bacterial populations of this particular place were identified. PMID:17061526

  11. Use of PCR-RFLP (Polymerase Chain Reaction - Restricted Fragment Length Polymorphism in the gene of the enzyme Stearoyl-CoA-Desaturase in Bubalus bubalis

    Directory of Open Access Journals (Sweden)

    H. Tonhati

    2010-02-01

    Full Text Available The milk is an important food because it contents Conjugated Linoleic Acids (CLA. These fatty acids are synthesized in mammary gland under action of the enzyme Stearoyl CoA-Desaturase (SCD and have showed some positive effects in human disease prevention and treatments. A variation of CLA in milk fat exists and can be partially explained by the different levels of expression of SCD. The aim was to study part of the encoding regions of SCD´s gene using PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism. Genomic DNA was extracted from lactating Murrah females. After this, PCR reactions were made by using primers Z43D1 that encloses exon I, II and intron I. The fragments amplified are composed by 938 pb. Then, RFLP techniques were applied in the fragments using the restriction enzymes Pst I and Sma I. The enzyme Pst I has generated fragments of 788pb and 150bp and the Sma I has generated fragments of 693pb and 245pb. All the animals showed the same migration standard for both enzymes, characterizing a genetic monomorphism for this region of SCD gene. The analysis determined that there aren’t genetic differences between these animals in the studied regions by using Pst I and Sma I enzymes.

  12. The effects of axial length on the fracture and fragmentation of expanding rings

    Directory of Open Access Journals (Sweden)

    Razorenov S.V.

    2012-08-01

    Full Text Available Rings of Ti-6Al-4V with aspect ratios (wall thickness:axial length of 1 : 1, 1 : 2 and 1 : 4 have been expanded to failure at radial strain rates εr ∼ 1 × 104 s−1 using 4340 (EN24T steel and Cu-ETP cylindrical drivers containing a column of RDX. Expansion velocity was measured using VISAR enabling calculation of the stress-strain history of the ring alongside fragment recovery with up to 98% original ring mass recovered. Using the recovered samples average fragment length and mass and final strain have been measured along with analysis of the fracture sites to determine the active failure mechanisms. Perfect rings (aspect ratio 1 : 1 were found to undergo necking before failure, whereas the longer rings failed though ductile tensile cracking at 45∘ to the radius. This data is then compared with finite element analysis results.

  13. Output Signal Power Analysis in Erbium-Doped Fiber Amplifier with Pump Power and Length Variation Using Various Pumping Techniques

    OpenAIRE

    Semmalar, S.; S. Malarkkan

    2013-01-01

    The scope of this paper is to analyze the output signal power with pump power and length variation in cascaded EDFA simulation model performance. This paper describes the simulation model of Erbium-Doped Fiber Amplifier (EDFA) of variable lengths (10 m, 50 m, and 120 m) with dual pumping techniques (dual forward pumping with two 980 nm wavelengths, dual forward and backward pumping with two 980 nm wavelengths) and Tri-pumping techniques. The simulation models consist of input source and pump ...

  14. Identification of blood meal sources of Lutzomyia longipalpis using polymerase chain reaction-restriction fragment length polymorphism analysis of the cytochrome B gene

    Directory of Open Access Journals (Sweden)

    Vítor Yamashiro Rocha Soares

    2014-06-01

    Full Text Available An analysis of the dietary content of haematophagous insects can provide important information about the transmission networks of certain zoonoses. The present study evaluated the potential of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP analysis of the mitochondrial cytochrome B (cytb gene to differentiate between vertebrate species that were identified as possible sources of sandfly meals. The complete cytb gene sequences of 11 vertebrate species available in the National Center for Biotechnology Information database were digested with Aci I, Alu I, Hae III and Rsa I restriction enzymes in silico using Restriction Mapper software. The cytb gene fragment (358 bp was amplified from tissue samples of vertebrate species and the dietary contents of sandflies and digested with restriction enzymes. Vertebrate species presented a restriction fragment profile that differed from that of other species, with the exception of Canis familiaris and Cerdocyon thous. The 358 bp fragment was identified in 76 sandflies. Of these, 10 were evaluated using the restriction enzymes and the food sources were predicted for four: Homo sapiens (1, Bos taurus (1 and Equus caballus (2. Thus, the PCR-RFLP technique could be a potential method for identifying the food sources of arthropods. However, some points must be clarified regarding the applicability of the method, such as the extent of DNA degradation through intestinal digestion, the potential for multiple sources of blood meals and the need for greater knowledge regarding intraspecific variations in mtDNA.

  15. Evidence of a normal mean telomere fragment length in patients with Ullrich-Turner syndrome

    DEFF Research Database (Denmark)

    Kveiborg, Marie; Gravholt, Claus Højbjerg; Kassem, M

    2001-01-01

    Clinical and epidemiological studies suggest that premature ageing and increased morbidity and mortality is present in Ullrich-Turner syndrome. We studied telomere restriction fragment length (TRFL) in 30 women with Ullrich-Turner syndrome and 30 age-matched control women. All Turner women had the...... 45,X karyotype verified by karyotyping. We found no difference in the mean TRFL in the young age group (TS: 7011+/-521 vs C: 7285+/-917 bp, P = 0.3), or in the older age group (TS: 7357+/-573 vs C: 7221+/-621 bp, P = 0.6). In conclusion, our data suggest that Ullrich-Turner syndrome is not associated...... with excessive telomere loss, at least when studied in peripheral blood leucocytes, and thus quite different from other premature ageing syndromes....

  16. Sac I Restriction Fragment Length Polymorphism (RFLP) related to the human CST2 gene.

    Science.gov (United States)

    Minaguchi, Kiyoshi; Kiriyama, Tateshi; Saitoh, Eiichi; Isemura, Satoko; Sanada, Kazuo

    2002-02-01

    Restriction Fragment Length Polymorphism (RFLP) related to cystatin gene (CST) family was detected in the Japanese population by using restriction enzyme Sac I. A polymorphic site, located at 0.9 kb from the 3' end of the CST2 gene, revealed a two allele polymorphism with band sizes of 3.5 kb and 8.3 kb by hybridization with probe including exon 2 of the CST1 gene. The gene frequencies in the Japanese population were 0.326 for 3.5 kb allele and 0.674 for 8.3 kb allele (n = 86). The phenotypes of the polymorphism showed no association with the previously reported electrophoretic cystatin SA protein phenotypes. PMID:12013824

  17. Restriction fragment length polymorphism of two HLA-B-associated transcripts genes in five autoimmune diseases

    DEFF Research Database (Denmark)

    Fugger, L; Morling, N; Ryder, L P;

    1991-01-01

    obtained shows that the HLA-B8 frequency is increased in BAT2/RsaI 2.7-kb positive pSS patients as compared to the corresponding controls indicating that the HLA-B8 association may be strongest. No missing or extra DNA fragments were observed in the disease groups when compared with controls indicating......The restriction fragment length polymorphism of the two human HLA-B-associated transcripts (BATs) genes, BAT1 and BAT2, identifying polymorphic bands of 12, 8, 2.5, and 1.1 kb, and at 3.3, 2.7, 2.3, and 0.9 kb, respectively, was investigated in patients with primary biliary cirrhosis (PBC...... significance when corrected for multiple comparisons. For pSS and SLE, the associations may be secondary to primary associations with HLA-B8 because the BAT2/RsaI 2.3-kb band, which is allelic to the BAT2/RsaI 2.7-kb band, is strongly negatively associated with HLA-B8 and HLA-DR3. The only significance...

  18. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP for rapid diagnosis of neonatal sepsis

    Directory of Open Access Journals (Sweden)

    Anusha Rohit

    2016-01-01

    Full Text Available Background & objectives: The difficulties in diagnosis of neonatal sepsis are due to varied clinical presentation, low sensitivity of blood culture which is considered the gold standard and empirical antibiotic usage affecting the outcome of results. Though polymerase chain reaction (PCR based detection of bacterial 16S rRNA gene has been reported earlier, this does not provide identification of the causative agent. In this study, we used restriction fragment length polymorphism (RFLP of amplified 16S rRNA gene to identify the organisms involved in neonatal sepsis and compared the findings with blood culture. Methods: Blood samples from 97 neonates were evaluated for diagnosis of neonatal sepsis using BacT/Alert (automated blood culture and PCR-RFLP. Results: Bacterial DNA was detected by 16S rRNA gene PCR in 55 cases, while BacT/Alert culture was positive in 34 cases. Staphylococcus aureus was the most common organism detected with both methods. Klebsiella spp. was isolated from four samples by culture but was detected by PCR-RFLP in five cases while Acinetobacter spp. was isolated from one case but detected in eight cases by PCR-RFLP. The sensitivity of PCR was found to be 82.3 per cent with a negative predictive value of 85.7 per cent. Eighty of the 97 neonates had prior exposure to antibiotics. Interpretation & conclusions:The results of our study demonstrate that PCR-RFLP having a rapid turnaround time may be useful for the early diagnosis of culture negative neonatal sepsis.

  19. Scalar wave propagation in random amplifying media: Influence of localization effects on length and time scales and threshold behavior

    International Nuclear Information System (INIS)

    We present a detailed discussion of scalar wave propagation and light intensity transport in three-dimensional random dielectric media with optical gain. The intrinsic length and time scales of such amplifying systems are studied and comprehensively discussed as well as the threshold characteristics of single- and two-particle propagators. Our semianalytical theory is based on a self-consistent Cooperon resummation, representing the repeated self-interference, and incorporates as well optical gain and absorption, modeled in a semianalytical way by a finite imaginary part of the dielectric function. Energy conservation in terms of a generalized Ward identity is taken into account.

  20. Mycobacterium tuberculosis complex differentiation using gyrB-restriction fragment length polymorphism analysis

    Directory of Open Access Journals (Sweden)

    Erica Chimara

    2004-11-01

    Full Text Available Mycobacterium tuberculosis complex (MTBC members are causative agents of human and animal tuberculosis. Differentiation of MTBC members is required for appropriate treatment of individual patients and for epidemiological purposes. Strains from six MTBC species - M. tuberculosis, M. bovis subsp. bovis, M. bovis BCG, M. africanum, M. pinnipedii, and "M. canetti" - were studied using gyrB-restriction fragment length polymorphism (gyrB-RFLP analysis. A table was elaborated, based on observed restriction patterns and published gyrB sequences. To evaluate applicability of gyrB-RFLP at Instituto Adolfo Lutz, São Paulo, Mycobacterial Reference Laboratory, 311 MTBC clinical isolates, previously identified using traditional methods as M. tuberculosis (306, M. bovis (3, and M. bovis BCG (2, were analyzed by gyrB-RFLP. All isolates were correctly identified by the molecular method, but no distinction between M. bovis and M. bovis BCG was obtained. Differentiation of M. tuberculosis and M. bovis is of utmost importance, because they require different treatment schedules. In conclusion, gyrB-RFLP is accurate and easy-to-perform, with potential to reduce time needed for conventional differentiation methods. However, application for epidemiological studies remains limited, because it cannot differentiate M. tuberculosis from M. africanum subtype II, and "M. canetti", M. africanum subtype I from M. pinnipedii, and. M. bovis from M. bovis BCG.

  1. Diversity analysis of magnetotactic bacteria in Lake Miyun, northern China, by restriction fragment length polymorphism.

    Science.gov (United States)

    Lin, Wei; Li, Jinhua; Schüler, Dirk; Jogler, Christian; Pan, Yongxin

    2009-08-01

    Magnetotactic bacteria (MTB) synthesize intracellular nano-scale crystals of magnetite or greigite within magnetosomes. MTB are ubiquitous in limnic and marine environments. In order to understand the diversity of MTB better, sediment samples were examined from Lake Miyun near Beijing by restriction fragment length polymorphism (RFLP). First, in silico analysis was used to evaluate the effectiveness of 12 sets of restriction endonucleases for distinguishing MTB sequences retrieved from the GenBank database. It was found that the tested restriction endonucleases had different power in the ability to differentiate the operational taxonomic units (OTUs) of MTB. Specifically, of the 12 sets of enzymes, MspI plus RsaI was found to be the most effective for correctly differentiating the OTUs of selected MTB sequences and it could detect 16 OTUs with appropriate OTUmin and OTUmax values (96.7% and 97.7%, respectively). The MspI plus RsaI RFLP analysis was then utilized to investigate the diversity of MTB in Lake Miyun sediment and it identified 8 OTUs (74.5% of the whole library) as MTB. Among these, 5 were affiliated to Alphaproteobacteria, while the rest belonged to the Nitrospira phylum. Interestingly, OTUs C, D and I displayed 91.8-98.4% similarity to "Magnetobacterium bavaricum". Together, these results demonstrated that the MspI plus RsaI RFLP analysis was useful for studying the diversity and change in community composition of uncultivated MTB from environmental samples. PMID:19168303

  2. Restriction fragment length polymorphism of the HLA-DP subregion and correlations to HLA-DP phenotypes

    DEFF Research Database (Denmark)

    Hyldig-Nielsen, J J; Morling, Niels; Ødum, Niels;

    1987-01-01

    The restriction fragment length polymorphism (RFLP) of the class II HLA-DP subregion of the major histocompatibility complex (MHC) of humans has been unraveled by Southern blotting using DP alpha and DP beta probes in a study of 46 unrelated individuals with known HLA-DP types. Contrary to earlier...

  3. Novel polymerase chain reaction-restriction fragment length polymorphism assay to determine internal transcribed spacer-2 group in the Chagas disease vector, Triatoma dimidiata (Latreille, 1811

    Directory of Open Access Journals (Sweden)

    Bethany Richards

    2013-06-01

    Full Text Available Triatoma dimidiata is the most important Chagas disease insect vector in Central America as this species is primarily responsible for Trypanosoma cruzi transmission to humans, the protozoan parasite that causes Chagas disease. T. dimidiata sensu lato is a genetically diverse assemblage of taxa and effective vector control requires a clear understanding of the geographic distribution and epidemiological importance of its taxa. The nuclear ribosomal internal transcribed spacer 2 (ITS-2 is frequently used to infer the systematics of triatomines. However, oftentimes amplification and sequencing of ITS-2 fails, likely due to both the large polymerase chain reaction (PCR product and polymerase slippage near the 5' end. To overcome these challenges we have designed new primers that amplify only the 3'-most 200 base pairs of ITS-2. This region distinguishes the ITS-2 group for 100% of known T. dimidiata haplotypes. Furthermore, we have developed a PCR-restriction fragment length polymorphism (RFLP approach to determine the ITS-2 group, greatly reducing, but not eliminating, the number of amplified products that need to be sequenced. Although there are limitations with this new PCR-RFLP approach, its use will help with understanding the geographic distribution of T. dimidiata taxa and can facilitate other studies characterising the taxa, e.g. their ecology, evolution and epidemiological importance, thus improving vector control.

  4. Large-Scale SNP Discovery and Genotyping for Constructing a High-Density Genetic Map of Tea Plant Using Specific-Locus Amplified Fragment Sequencing (SLAF-seq.

    Directory of Open Access Journals (Sweden)

    Jian-Qiang Ma

    Full Text Available Genetic maps are important tools in plant genomics and breeding. The present study reports the large-scale discovery of single nucleotide polymorphisms (SNPs for genetic map construction in tea plant. We developed a total of 6,042 valid SNP markers using specific-locus amplified fragment sequencing (SLAF-seq, and subsequently mapped them into the previous framework map. The final map contained 6,448 molecular markers, distributing on fifteen linkage groups corresponding to the number of tea plant chromosomes. The total map length was 3,965 cM, with an average inter-locus distance of 1.0 cM. This map is the first SNP-based reference map of tea plant, as well as the most saturated one developed to date. The SNP markers and map resources generated in this study provide a wealth of genetic information that can serve as a foundation for downstream genetic analyses, such as the fine mapping of quantitative trait loci (QTL, map-based cloning, marker-assisted selection, and anchoring of scaffolds to facilitate the process of whole genome sequencing projects for tea plant.

  5. Large-Scale SNP Discovery and Genotyping for Constructing a High-Density Genetic Map of Tea Plant Using Specific-Locus Amplified Fragment Sequencing (SLAF-seq).

    Science.gov (United States)

    Ma, Jian-Qiang; Huang, Long; Ma, Chun-Lei; Jin, Ji-Qiang; Li, Chun-Fang; Wang, Rong-Kai; Zheng, Hong-Kun; Yao, Ming-Zhe; Chen, Liang

    2015-01-01

    Genetic maps are important tools in plant genomics and breeding. The present study reports the large-scale discovery of single nucleotide polymorphisms (SNPs) for genetic map construction in tea plant. We developed a total of 6,042 valid SNP markers using specific-locus amplified fragment sequencing (SLAF-seq), and subsequently mapped them into the previous framework map. The final map contained 6,448 molecular markers, distributing on fifteen linkage groups corresponding to the number of tea plant chromosomes. The total map length was 3,965 cM, with an average inter-locus distance of 1.0 cM. This map is the first SNP-based reference map of tea plant, as well as the most saturated one developed to date. The SNP markers and map resources generated in this study provide a wealth of genetic information that can serve as a foundation for downstream genetic analyses, such as the fine mapping of quantitative trait loci (QTL), map-based cloning, marker-assisted selection, and anchoring of scaffolds to facilitate the process of whole genome sequencing projects for tea plant. PMID:26035838

  6. Characterization of western European field isolates and vaccine strains of avian infectious laryngotracheitis virus by restriction fragment length polymorphism and sequence analysis.

    Science.gov (United States)

    Neff, C; Sudler, C; Hoop, R K

    2008-06-01

    Infectious laryngotracheitis is a dramatic disease of the upper respiratory tract in poultry caused by a herpesvirus. In this study we investigated the characteristics of western European field isolates of infectious laryngotracheitis virus (ILTV) to gain more information on their diversity. The examined 104 isolates, collected from acute outbreaks during the last 35 years, originated from eight different countries: Switzerland (48), Germany (21), Sweden (14), the United Kingdom (9), Italy (5), Belgium (4), Austria (2), and Norway (1). Two vaccines, a chicken embryo origin product and a tissue culture origin product, were included in the survey. Polymerase chain reaction (PCR) was performed to amplify a 2.1-kb DNA fragment of ILTV using primers generated for the thymidine kinase (TK) gene. After digestion of the resulting PCR products by restriction endonuclease HaeIII, restriction fragment length polymorphism analysis was carried out. PCR amplicons of three field isolates and both vaccine strains were selected for sequencing. Here 98 field isolates showed the same cleavage pattern and were identical to both vaccine strains (clone 1). They differed from five Swiss isolates with identical cleavage pattern (clone 2) and one Swedish isolate (clone 3). The present study demonstrated that at least three clones of ILTV have been circulating in western Europe during the last 35 years. The 104 isolates analyzed showed a high genetic similarity regarding the TK gene, and a large majority of the field isolates (98/104) were genetically related to the vaccine strains. PMID:18646457

  7. Chemoattractive capacity of different lengths of nerve fragments bridging regeneration chambers for the repair of sciatic nerve defects

    Institute of Scientific and Technical Information of China (English)

    Jiren Zhang; Yubo Wang; Jincheng Zhang

    2012-01-01

    A preliminary study by our research group showed that 6-mm-long regeneration chamber bridging is equivalent to autologous nerve transplantation for the repair of 12-mm nerve defects.In this study,we compared the efficacy of different lengths (6,8,10 mm) of nerve fragments bridging 6-mm regeneration chambers for the repair of 12-mm-long nerve defects.At 16 weeks after the regeneration chamber was implanted,the number,diameter and myelin sheath thickness of the regenerated nerve fibers,as well as the conduction velocity of the sciatic nerve and gastrocnemius muscle wet weight ratio,were similar to that observed with autologous nerve transplantation.Our results demonstrate that 6-,8-and 10-mm-long nerve fragments bridging 6-mm regeneration chambers effectively repair 12-mm-long nerve defects.Because the chemoattractive capacity is not affected by the length of the nerve fragment,we suggest adopting 6-mm-long nerve fragments for the repair of peripheral nerve defects.

  8. A rapid and reliable PCR-restriction fragment length polymorphism (RFLP) marker for the identification of Amaranthus cruentus species

    OpenAIRE

    Park, Young-Jun; Nishikawa, Tomotaro; Matsushima, Kenichi; Minami, Mineo; Nemoto, Kazuhiro

    2014-01-01

    A rapid and reliable PCR-restriction fragment length polymorphism (RFLP) marker was developed to identify the Amaranthus cruentus species by comparing sequences of the starch branching enzyme (SBE) locus among the three cultivated grain amaranths. We determined the partial SBE genomic sequence in 72 accessions collected from diverse locations around the world by direct sequence analysis. Then, we aligned the gene sequences and searched for restriction enzyme cleavage sites specific to each sp...

  9. Chemoattractive capacity of different lengths of nerve fragments bridging regeneration chambers for the repair of sciatic nerve defects

    OpenAIRE

    Zhang, Jiren; Wang, Yubo; Zhang, Jincheng

    2012-01-01

    A preliminary study by our research group showed that 6-mm-long regeneration chamber bridging is equivalent to autologous nerve transplantation for the repair of 12-mm nerve defects. In this study, we compared the efficacy of different lengths (6, 8, 10 mm) of nerve fragments bridging 6-mm regeneration chambers for the repair of 12-mm-long nerve defects. At 16 weeks after the regeneration chamber was implanted, the number, diameter and myelin sheath thickness of the regenerated nerve fibers, ...

  10. A sex chromosomal restriction-fragment-length marker linked to melanoma-determining Tu loci in Xiphophorus

    OpenAIRE

    Schartl, Manfred

    2012-01-01

    In Xiphophorus, the causative genetic information for melanoma formation has been assigned by classical genetics to chromosomal loci, which are located on the sex chromosomes. In our attempts to molecularly clone these melanoma-determining loci, named Tu, we have looked for restriction-fragment-length markers (RFLMs) linked to the Tu loci. These RFLMs should be useful in obtaining a physical map of a Tu locus, which will aid in the cloning of the corresponding sequences. DNA samples from vari...

  11. DNA restriction fragment length polymorphism of HLA-DR2 haplotypes in normal individuals and in patients with rheumatoid arthritis.

    OpenAIRE

    Singal, D P; Reid, B.; Green, D; Bensen, W. G.; D'Souza, M

    1990-01-01

    A strong association between HLA-DR4 and rheumatoid arthritis (RA) has been found in a number of populations. In contrast, the incidence of DR2 is decreased in patients with RA, suggesting that this specificity may confer some protection against the disease. A number of subtypes of DR2 have been defined by serology, by responses in mixed lymphocyte culture reaction, and, more recently, by restriction fragment length polymorphism. These subtypes of DR2 are in linkage disequilibrium with differ...

  12. A sex chromosomal restriction-fragment-length marker linked to melanoma-determining Tu loci in Xiphophorus.

    Science.gov (United States)

    Schartl, M

    1988-07-01

    In Xiphophorus, the causative genetic information for melanoma formation has been assigned by classical genetics to chromosomal loci, which are located on the sex chromosomes. In our attempts to molecularly clone these melanoma-determining loci, named Tu, we have looked for restriction-fragment-length markers (RFLMs) linked to the Tu loci. These RFLMs should be useful in obtaining a physical map of a Tu locus, which will aid in the cloning of the corresponding sequences. DNA samples from various Xiphophorus strains and hybrids including those bearing different Tu wild-type, deletion and translocation chromosomes, were screened for the presence of random RFLMs using homologous or heterologous sequences as hybridization probes. We find an EcoRI restriction fragment which shows limited crosshybridization to the v-erb B gene--but not representing the authentic c-erb B gene of Xiphophorus--to be polymorphic with respect to different sex chromosomes. Linkage analysis revealed that a 5-kb fragment is linked to the Tu-Sd locus on the X chromosome, a 7-kb fragment is linked to the Tu-Sr locus on the Y chromosome, both of Xiphophorus maculatus, and that a 12-kb fragment is linked to the Tu-Li locus on the X chromosome of Xiphophorus variatus. Using different chromosomal mutants this RFLM has been mapped to a frequent deletion/translocation breakpoint of the X chromosome, less than 0.3 cM apart from the Tu locus. PMID:2841190

  13. Processing of Phonemic Consonant Length: Semantic and Fragment Priming Evidence from Bengali.

    Science.gov (United States)

    Kotzor, Sandra; Wetterlin, Allison; Roberts, Adam C; Lahiri, Aditi

    2016-03-01

    Six cross-modal lexical decision tasks with priming probed listeners' processing of the geminate-singleton contrast in Bengali, where duration alone leads to phonemic contrast ([pata] 'leaf' vs. [pat:a] 'whereabouts'), in order to investigate the phonological representation of consonantal duration in the lexicon. Four form-priming experiments (auditory fragment primes and visual targets) were designed to investigate listeners' sensitivity to segments of conflicting duration. Each prime derived from a real word ([k(h)[symbol: see text]m]/[g(h)en:]) was matched with a mispronunciation of the opposite duration (*[k(h)[symbol: see text]m:]/*[g(h)en]) and both were used to prime the full words [k(h)[symbol: see text]ma] ('forgiveness') and [g(h)en:a] ('disgust') respectively. Although all fragments led to priming, the results showed an asymmetric pattern. The fragments of words with singletons mispronounced as geminates led to equal priming, while those with geminates mispronounced as singletons showed a difference. The priming effect of the real-word geminate fragment was significantly greater than that of its corresponding nonword singleton fragment. In two subsequent semantic priming tasks with full-word primes a stronger asymmetry was found: nonword geminates (*[k(h)[symbol: see text]m:a]) primed semantically related words ([marjona] 'forgiveness') but singleton nonword primes (*[ghena]) did not show priming. This overall asymmetry in the tolerance of geminate nonwords in place of singleton words is attributed to a representational mismatch and points towards a moraic representation of duration. While geminates require a mora which cannot be derived from singleton input, the additional information in geminate nonwords does not create a similar mismatch. PMID:27089807

  14. HLA-DPB1 typing with polymerase chain reaction and restriction fragment length polymorphism technique in Danes

    DEFF Research Database (Denmark)

    Hviid, T V; Madsen, H O; Morling, N

    1992-01-01

    We have used the polymerase chain reaction (PCR) in combination with the restriction fragment length polymorphism (RFLP) technique for HLA-DBP1 typing. After PCR amplification of the polymorphic second exon of the HLA-DPB1 locus, the PCR product was digested with seven allele-specific restriction...... PCR-ASO technique. The frequencies of the HLA-DPB1 genotypes deduced from the results of PCR-RFLP typing were estimated in 71 healthy Danes.......We have used the polymerase chain reaction (PCR) in combination with the restriction fragment length polymorphism (RFLP) technique for HLA-DBP1 typing. After PCR amplification of the polymorphic second exon of the HLA-DPB1 locus, the PCR product was digested with seven allele-specific restriction...... endonucleases: RsaI, FokI, ApaI, SacI, BstUI, EcoNI, and DdeI, and the DNA fragments were separated by electrophoresis in agarose gels. Altogether, 71 individuals were investigated and 16 different HLA-DPB1 types were observed in 26 different heterozygotic combinations, as well as five possible homozygotes...

  15. Large-Scale SNP Discovery and Genotyping for Constructing a High-Density Genetic Map of Tea Plant Using Specific-Locus Amplified Fragment Sequencing (SLAF-seq)

    OpenAIRE

    Ma, Jian-Qiang; Huang, Long; Ma, Chun-Lei; Jin, Ji-Qiang; Li, Chun-Fang; Wang, Rong-Kai; Zheng, Hong-Kun; Yao, Ming-Zhe; Chen, Liang

    2015-01-01

    Genetic maps are important tools in plant genomics and breeding. The present study reports the large-scale discovery of single nucleotide polymorphisms (SNPs) for genetic map construction in tea plant. We developed a total of 6,042 valid SNP markers using specific-locus amplified fragment sequencing (SLAF-seq), and subsequently mapped them into the previous framework map. The final map contained 6,448 molecular markers, distributing on fifteen linkage groups corresponding to the number of tea...

  16. Genotyping of the fish rhabdovirus, viral haemorrhagic septicaemia virus, by restriction fragment length polymorphisms

    DEFF Research Database (Denmark)

    Einer-Jensen, Katja; Winton, J.; Lorenzen, Niels

    The aim of this study was to develop a standardized molecular assay that used limited resources and equipment for routine genotyping of isolates of the fish rhabdovirus, viral haemorrhagic septicaemia virus (VHSV). Computer generated restriction maps, based on 62 unique full-length (1524 nt...

  17. Rapid diagnosis and genotyping of Leishmania isolates from cutaneous and visceral leishmaniasis by microcapillary cultivation and polymerase chain reaction-restriction fragment length polymorphism of miniexon region.

    Science.gov (United States)

    Serin, Mehmet S; Daglioglu, Kenan; Bagirova, Melahat; Allahverdiyev, Adil; Uzun, Soner; Vural, Zeynep; Kayar, Begum; Tezcan, Seda; Yetkin, Mesut; Aslan, Gonul; Emekdas, Gurol; Koksal, Fatih

    2005-11-01

    We have performed a combination of microcapillary cultivation method and restriction fragment length polymorphism (RFLP) analysis of amplified products by 1 single PCR of miniexon region of Leishmania for molecular diagnosis and genotyping of different Leishmania species isolated from cutaneous leishmaniasis (CL) and visceral leishmaniasis. We have analyzed 10 microcapillary cultivated isolates from cutaneous cases and 5 microcapillary cultivated isolates from visceral cases (totally 15) by polymerase chain reaction-RFLP (PCR-RFLP). Of 10 isolates, 3 (30%) were genotyped as Leishmania infantum and 7 (70%) of 10 isolates were genotyped as Leishmania tropica from the microcapillary cultivated isolates of cutaneous cases. On the other hand, all 5 isolates (100%) were genotyped as L. infantum from microcapillary cultivated visceral cases. Our most interesting finding is the presence of 3 L. infantum isolates in CL cases without kala-azar history. Therefore, we suggest that further investigations must be done about this subject. On the other hand, we suggest the combination of microcapillary culture method and PCR-RFLP of miniexon region of leishmaniae can be used in routine laboratory experimentation because of their simple, cheap, and rapid benefits (within a week), whereas other different approaches offer a multitude of valid taxonomic characters for species identification. PMID:16249065

  18. Detection of disease-specific restriction fragment length polymorphisms in pemphigus vulgaris linked to the DQwl and DQw3 alleles of the HLA-D region

    International Nuclear Information System (INIS)

    Pemphigus vulgaris in Israeli Ashkenazi and non-Ashkenazi Jews and in Austrian non-Jewish patients is strongly associated with the DR4 and DRw6 alleles of the HLA-D region class II genes. Restriction fragment length polymorphism analysis was undertaken with DQβ, DQα, and DRβ cDNA probes. Hybridization with the DQβ probe identifies Pvu II, BamHI, and EcoRV fragments that absolutely discriminate pemphigus vulgaris patients from healthy DR-, DQ-, and ethnic-matched controls. In contrast the DQα and DRβ probes failed to identify disease-specific restriction fragment length polymorphism fragments. These studies indicate that DQw1 and DQw3 polymorphisms carried by pemphigus vulgaris patients may be directly involved in predisposition to the disease or may be tightly linked to the susceptibility gene itself. To our knowledge, this is the first example of an HLA restriction fragment length polymorphism that is highly associated with susceptibility to autoimmune disease

  19. Separation of Three Species of Ditylenchus and Some Host Races of D. dipsaci by Restriction Fragment Length Polymorphism.

    Science.gov (United States)

    Wendt, K R; Vrain, T C; Webster, J M

    1993-12-01

    This study examined the ribosomal cistron of Ditylenchus destructor, D. myceliophagus and seven host races of D. dipsaci from different geographic locations. The three species showed restriction fragment length polymorphisms (RFLPs) in the ribosomal cistron, the 18S rDNA gene, and the ribosomal internal transcribed spacer (ITS). Southern blot analysis with a 7.5-kb ribosomal cistron probe differentiated the five host races of D. dipsaci examined. Polymerase chain reaction (PCR) amplification of the ITS, followed by digestion with some restriction endonucleases (but not others), produced restriction fragments diagnostic of the giant race. Because the PCR product from D. myceliophagus and the host races of D. dipsaci was about 900 base pairs and the ITS size in D. destructor populations was 1,200 base pairs, mixtures of populations could be detected by PCR amplification. ITS fragments differentiated between D. dipsaci and Aphelenchoides rhyntium in mixed populations. This study establishes the feasibility of differentiation of the host races of D. dipsaci by probing Southern blots with the whole ribosomal cistron. PMID:19279809

  20. Restriction fragment length polymorphism within the class I gene loci of the equine major histocompatibility complex

    International Nuclear Information System (INIS)

    Fourteen standard bred horses were serotyped as homozygous for 1 of 6 Equine Leukocyte Antigen (ELA) specificities. DNA was purified from peripheral leukocytes and digested with Hind III or Pvu II. Southern blot hybridization analysis was carried out using a 32P-labeled mouse cDNA probe (PH2IIa) specific for class I MHC genes. Both enzymes generated blots that contained a large number of bands (23 to 30) per horse. Significant polymorphism existed among most fragment sizes, while a dozen highly conserved band sizes suggested the presence of Qa/tla - like genes. Only 2 animals (both W6's) showed identical band patterns. Polymorphism was greatest between horses of different serotypes and was significantly decreased within serotypes. Unique bands were present on both blots for both W1's and W6's and may account for the serologic specificity seen in ELA W1 and W6 horses. This study is consistent with the findings in other higher vertebrates and implies that the MHC of the horse includes a highly polymorphic class I multigene family

  1. GENETIC DIVERSITY OF CLINICAL AND ENVIRONMENTAL ISOLATES OF VIBRIO CHOLERAE DETERMINED BY AMPLIFIED FRAGMENT LENGTH POLYMORPHISM FINGERPRINTING. (R824995)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  2. GENETIC DIVERSITY OF VIBRIO CHOLERAE IN CHESAPEAKE BAY DETERMINED BY AMPLIFIED FRAGMENT LENGTH POLYMORPHISM FINGERPRINTING. (R824995)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  3. Origin of Spanish invasion by the zebra mussel, Dreissena polymorpha (Pallas, 1771) revealed by amplified fragment length polymorphism (AFLP) fingerprinting

    NARCIS (Netherlands)

    Rajagopal, S.; Pollux, B.J.A.; Peters, J.L.; Cremers, G.; Moon- van der Staay, S.Y.; Alen, van T.; Eygensteyn, J.; Hoek, van A.H.A.M.; Palau, A.; Vaate, de A.B.; Velde, van der G.

    2009-01-01

    The zebra mussel, Dreissena polymorpha is an aquatic nuisance invasive species originally native to the Ponto-Caspian region where it is found in lakes and delta areas of large rivers draining into the Black and Caspian seas. The dispersal of D. polymorpha began at the end of the 18th century, at a

  4. Exploration of amplified fragment length polymorphism analysis as an effective tool for discriminating pathogenic strains of bacteria

    OpenAIRE

    Allen, Robert; Weinbrecht,; Taylor,, Samuel ,; Beaumann,

    2012-01-01

    K Weinbrecht,1 A Taylor,2 C Beaumann,3 RW Allen11Department of Forensic Sciences, Center for Health Sciences, Oklahoma State University, Tulsa, OK; 2Centers for Disease Control, Atlanta, GA; 3PharmaNet-i3, Indianapolis, IN, USABackground: The detrimental effect pathogens used as bioweapons could have on the US is sufficient to warrant extensive efforts to establish preparedness to prevent, and, if necessary, respond to such an event. The objective of this research was to adapt and refine ampl...

  5. Genotypic characterization of Salmonella by multilocus sequence typing, pulsed-field gel electrophoresis and amplified fragment length polymorphism

    DEFF Research Database (Denmark)

    Torpdahl, Mia; Skov, Marianne N.; Sandvang, Dorthe; Baggesen, Dorte Lau

    2005-01-01

    Molecular typing is an important tool in surveillance and outbreak investigations Of human Salmonella infections. In this study, three molecular typing methods were used to investigate the discriminatory ability, reproducibility and the genetic relationship between 110 Salmonella enterica...... analyze when compared to AFLP. PFGE is the therefore the preferred molecular typing method for surveillance and outbreak investigations, whereas AFLP is most useful for local outbreak investigations....

  6. Use of amplified fragment length polymorphism analysis to identify medically important Candida spp., including C-dubliniensis

    NARCIS (Netherlands)

    Borst, A; Theelen, B; Reinders, E; Boekhout, T; Fluit, AC; Savelkoul, PHM

    2003-01-01

    Non-Candida albicans Candida species are increasingly being isolated. These species show differences in levels of resistance to antimycotic agents and mortality. Therefore, it is important to be able to correctly identify the causative organism to the species level. Identification of C. dubliniensis

  7. Characterization of Bovine Calpastatin Gene in Nelore Cattle Using Polymerase Chain Reaction-Restricted Fragment Length Polymorphisms

    Directory of Open Access Journals (Sweden)

    Alireza Majidi

    2009-01-01

    Full Text Available Problem statement: In beef cattle production, of meat quality and carcass traits are important. Traditionally beef cattle breeding programs unfortunately are time consuming and also recording of carcass and growth traits need heavy cost, Approach: Marker Assisted Selection (MAS should be utilized in beef herds, along with economically important phenotypic traits, for genetic progress to made with respect to improving the uniformity and consistency of beef. Blood samples were collected from 41 nelor cattle in Malaysia. Forward and reversed primers amplified a 1552 bp fragment from calpastatin gene. XmnI enzyme was used for restriction analysis of PCR products. Result: Overall, the frequency of alleles A and B in the studied breeds were estimated as 0.42 and 0.58, respectively. In this study we calculated genotype frequency AA, AB and BB 12.2, 58.53 and 29.27% respectively and also observed heterozygosity, expected heterozygosity and average value of heterozygosity were 0.58, 0.49 and 0.48 respectively. Highest frequency of allele was B (0.58 and lowest was A (0.42 This Nelor cattle population was in the Hardy-Weinberg equilibrium. Conclusion: Perhaps, this molecular genetic information helps breeders for designing the proper genetic selection program in the development direction of this breed.

  8. Molecular Characterization of Mycobacterium bovis Isolates with High Copy Number of IS6110 by Restriction Fragment Length Polymorphism

    Directory of Open Access Journals (Sweden)

    Behnam Rafiee

    2014-12-01

    Full Text Available Background: Mycobacterium bovis is the causative agent of bovine tuberculosis and belongs to the Mycobacterium tuberculosis complex. M. bovis usually carries only one or a few copies of the insertion sequence IS6110 in its genome. The aim of this study was evaluation of copy number of IS6110 in M. bovis isolates by restriction fragment length polymorphism (RFLP method. Materials and Methods: In this experimental study, 25 lymph node specimens of tuberculin-positive cattle were collected and cultured by standard methods, afterward genomic DNA was extracted by chloroform-isoamyl alcohol. Genetic studies were conducted by Pvull and DNA hybridization with IS6110. Results: Two isolates displayed more than of 4 copies of IS6110 by RFLP (IS6110-RFLP method. Conclusion: The results of this study are unique and specific in Iran but reported in the world rarely. Therefore the new strains of M. bovis imported to Iran from other countries of the world.

  9. The suitability of restriction fragment length polymorphism markers for evaluating genetic diversity among and synteny between mosquito species.

    Science.gov (United States)

    Severson, D W; Mori, A; Zhang, Y; Christensen, B M

    1994-04-01

    Restriction fragment length polymorphism (RFLP) markers derived from the yellow fever mosquito, Aedes aegypti, were used in hybridizations to genomic DNA of the following mosquito species: Ae. albopictus, Ae. togoi, Armigeres subalbatus, Culex pipiens, and Anopheles gambiae. Interspecific hybridization with Ae. aegypti probes varied from 50% (An. gambiae) to 100% (Ae. albopictus) under high stringency conditions. We demonstrated the usefulness of using RFLP profiles to examine genetic diversity between mosquito populations; Ae. aegypti RFLP markers were used to examine genetic relatedness between 10 laboratory strains of Ae. aegypti as well as between nine populations representing four Cx. pipiens subspecies. These results indicate that many Ae. aegypti RFLP markers should have direct applicability in gaining a better understanding of genome structure in other mosquito species, including RFLP linkage mapping and determinations of genetic relatedness among field populations. PMID:7909414

  10. A Glutamine/Asparagine-Rich Fragment of Gln3, but not the Full-Length Protein, Aggregates in Saccharomyces cerevisiae.

    Science.gov (United States)

    Antonets, K S; Sargsyan, H M; Nizhnikov, A A

    2016-04-01

    The amino acid sequence of protein Gln3 in yeast Saccharomyces cerevisiae has a region enriched with Gln (Q) and Asn (N) residues. In this study, we analyzed the effects of overexpression of Gln3 and its Q/N-rich fragment fused with yellow fluorescent protein (YFP). Being overexpressed, full-length Gln3-YFP does not form aggregates, inhibits vegetative growth, and demonstrates nuclear localization, while the Q/N-rich fragment (Gln3QN) fused with YFP forms aggregates that do not colocalize with the nucleus and do not affect growth of the cells. Although detergent-resistant aggregates of Gln3QN are formed in the absence of yeast prions, the aggregation of Gln3QN significantly increases in the presence of [PIN(+)] prion, while in the presence of two prions, [PSI(+)] and [PIN(+)], the percentage of cells with Gln3QN aggregates is significantly lower than in the strain bearing only [PIN(+)]. Data on colocalization demonstrate that this effect is mediated by interaction between Gln3QN aggregates and [PSI(+)] and [PIN(+)] prions. PMID:27293098

  11. Detection of a single base exchange in PCR-amplified DNA fragments using agarose gel electrophoresis containing bisbenzimide-PEG.

    OpenAIRE

    Müller, M; Kruse, L; Tabrett, A M; Barbara, D.J.

    1997-01-01

    Using PCR fragments of known sequences derived from isolates of two related fungal species, simple submarine electrophoresis in agarose gels containing a bisbenzimide-PEG conjugate (H.A.-Yellow) has been shown to be capable of distinguishing DNA fragments 567 bp long which differ by as little as a single base change. However, only changes affecting bisbenzimide binding sites (which consist of at least four consecutive A/T bases) alter mobility; other changes are ineffective. A second ligand (...

  12. Rational Design of High-Number dsDNA Fragments Based on Thermodynamics for the Construction of Full-Length Genes in a Single Reaction.

    Directory of Open Access Journals (Sweden)

    Bhagyashree S Birla

    Full Text Available Gene synthesis is frequently used in modern molecular biology research either to create novel genes or to obtain natural genes when the synthesis approach is more flexible and reliable than cloning. DNA chemical synthesis has limits on both its length and yield, thus full-length genes have to be hierarchically constructed from synthesized DNA fragments. Gibson Assembly and its derivatives are the simplest methods to assemble multiple double-stranded DNA fragments. Currently, up to 12 dsDNA fragments can be assembled at once with Gibson Assembly according to its vendor. In practice, the number of dsDNA fragments that can be assembled in a single reaction are much lower. We have developed a rational design method for gene construction that allows high-number dsDNA fragments to be assembled into full-length genes in a single reaction. Using this new design method and a modified version of the Gibson Assembly protocol, we have assembled 3 different genes from up to 45 dsDNA fragments at once. Our design method uses the thermodynamic analysis software Picky that identifies all unique junctions in a gene where consecutive DNA fragments are specifically made to connect to each other. Our novel method is generally applicable to most gene sequences, and can improve both the efficiency and cost of gene assembly.

  13. Ankylosing spondylitis and HLA-B27: restriction fragment length polymorphism and sequencing of an HLA-B27 allele from a patient with ankylosing spondylitis

    OpenAIRE

    1993-01-01

    Two groups of patients with ankylosing spondylitis (AS) from England and Poland were examined for restriction fragment length polymorphisms (RFLPs) associated with the disease. No preferential association was found between the 9.2 kb PvuII fragment in HLA-B27 positive patients with AS compared with HLA-B27 healthy subjects as had been previously reported. In the English group, however, a 14 kb PvuII fragment was more common in HLA-B27 positive subjects with AS than in normal controls. Also 4....

  14. Development of a PCR-restriction fragment length polymorphism protocol for rapid detection and differentiation of four cockroach vectors (group I "Dirty 22" species) responsible for food contamination and spreading of foodborne pathogens: public health importance.

    Science.gov (United States)

    Sulaiman, Irshad M; Anderson, Mickey; Khristova, Marina; Tang, Kevin; Sulaiman, Nikhat; Phifer, Edwin; Simpson, Steven; Kerdahi, Khalil

    2011-11-01

    Assessing the adulteration of food products and the presence of filth and extraneous materials is one of the measures that the U.S. Food and Drug Administration (FDA) utilizes in implementing regulatory actions of public health importance. To date, 22 common pest species (also known as the "Dirty 22" species) have been regarded by this agency as the spreaders of foodborne diseases. We have further categorized the Dirty 22 species into four groups: I has four cockroach species, II has two ant species, III has 12 fly species, and IV has four rodent species. The presence of any Dirty 22 species is also considered an indicator of unsanitary conditions in food processing and storage facilities. In this study, we describe the development of a two-step nested PCR protocol to amplify the small subunit ribosomal gene of group I Dirty 22 species that include four cockroach species: Blattella germanica, Blatta orientalis, Periplaneta americana, and Supella longipalpa, along with the development of a PCR-restriction fragment length polymorphism method for rapid detection and differentiation of these violative species. This method will be utilized when the specimen cannot be identified with conventional microscopic taxonomic methods, especially when only small body parts are separated and recovered from food samples for analysis or when these body parts are in a decomposed state. This new PCR-restriction fragment length polymorphism will provide correct identification of group I Dirty 22 species; this information can then be used in regulation and prevention of foodborne pathogens. PMID:22054189

  15. Prevalence of Trichomonas spp. in domestic pigeons in Shandong Province, China, and genotyping by restriction fragment length polymorphism.

    Science.gov (United States)

    Jiang, Xiyue; Sun, Jingjing; Wang, Fangkun; Li, Hongmei; Zhao, Xiaomin

    2016-05-01

    Oropharyngeal swabs (n = 609) were collected randomly from 80,000 domestic pigeons (Columba livia domestica) on five pigeon farms and at one pigeon slaughterhouse in Shandong Province, China, from September 2012 to July 2013. Trichomonas spp. were detected in 206/609 (33.8%) samples. The prevalence was 14.9-31.1%, depending on different levels of sanitation and management, and was 4.8% in nestling pigeons, 13.6% in breeding pigeons and 35.2% in adolescent pigeons. Trichomonas gallinae genotypes A and B, and Trichomonas tenax-like isolates were identified by PCR-restriction fragment length polymorphism (RFLP) analysis and sequencing of the 5.8S rDNA-internal transcribed spacer (ITS) regions. RFLP analysis with the restriction enzyme BsiEI generated different RFLP band patterns between T. gallinae and T.tenax-like isolates. When BsiEI RFLP analysis was combined with HaeIII RFLP analysis, all infection types of T. gallinae and T.tenax-like isolates could be identified. PMID:27068150

  16. Pst I restriction fragment length polymorphism of the human placental alkaline phosphatase gene in normal placentae and tumors

    International Nuclear Information System (INIS)

    The structure of the human placental alkaline phosphatase gene from normal term placentae was studied by restriction enzyme digestion and Southern blot analysis using a cDNA probe to the gene for the placental enzyme. The DNA digests fall into three distinct patterns based on the presence and intensity of an extra 1.1-kilobase Pst I Band. The extra 1.1-kilobase band is present in 9 of 27 placenta samples, and in 1 of these samples the extra band is present at double intensity. No polymorphism was revealed by digestion with restriction enzymes EcoRI, Sma I, BamHI, or Sac I. The extra Pst I-digestion site may lie in a noncoding region of the gene because no correlation was observed between the restriction fragment length polymorphism and the common placental alkaline phosphatase alleles identified by starch gel electrophoresis. In addition, because placental alkaline phosphatase is frequently re-expressed in neoplasms, the authors examined tissue from ovarian, testicular, and endometrial tumors and from BeWo choriocarcinoma cells in culture. The Pst I-DNA digestion patterns from these cells and tissues were identical to those seen in the normal ovary and term placentae. The consistent reproducible digestion patterns seen in DNA from normal and tumor tissue indicate that a major gene rearrangement is not the basis for the ectopic expression of placental alkaline phosphatase in neoplasia

  17. A novel hepatitis B virus genotyping system by using restriction fragment length polymorphism patterns of S gene amplicons

    Institute of Scientific and Technical Information of China (English)

    Guo-Bing Zeng; Shu-Juan Wen; Zhan-Hui Wang; Li Yan; Jian Sun; Jin-Lin Hou

    2004-01-01

    AIM: Traditional hepatitis B virus (HBV) genotyping methods using restriction fragment length polymorphism (RFLP) can reliably identify genotypes A to F. As HBV genotypes G and H have been recently identified, this study was to establish an accurate and simple genotyping method for all eight HBV genotypes (A to H).METHODS: Two hundred and forty HBV small S sequences obtained from GeneBank were analysed for restriction enzyme sites that would be genotype-specific. Restriction patterns following digestion with restriction enzymes BsrⅠ,StyⅠ, DpnⅠ, HpaⅡ, and EaeⅠ, were determined to identify all eight HBV genotypes. Mixed genotype infections were confirmed by cloning and further RFLP analysis.RESULTS: The new genotyping method could identify HBV genotypes A to H. Genotypes B and C could be determined by a single step digestion with BsrⅠ and StyⅠ in parallel. This was particularly useful in the Far East where genotypes B and C are predominant. Serum samples from 187 Chinese HBV carriers were analysed with this genotyping system, and the genotype distribution was 1.1% (2), 51.9% (97), 40.6% (76) and 4.8%(9) for genotypes A, B, C, and D, respectively. Mixed genotypes were found in only 3 patients (1.6%). Sequence data analysis confirmed the validity of this new method.CONCLUSION: This HBV genotyping system can identify all eight HBV genotypes. It is accurate and simple, and can be widely used for studies on HBV genotyping.

  18. Transmission of tuberculosis in Havana, Cuba: a molecular epidemiological study by IS6110 restriction fragment length polymorphism typing

    Directory of Open Access Journals (Sweden)

    Diaz R

    2001-01-01

    Full Text Available The combination of molecular and conventional epidemiological methods has improved the knowledge about the transmission of tuberculosis in urban populations. To examine transmission of tuberculosis in Havana, Cuba, with DNA fingerprinting, we studied 51 out of 92 Mycobacterium tuberculosis strains isolated from tuberculosis patients who resided in Havana and whose infection was culture-confirmed in the period from September 1997 to March 1998. Isolates from 28 patients (55% had unique IS6110 restriction fragment length polymorphism (RFLP patterns, while isolates from 23 others (45% had identical patterns and belonged to 7 clusters. Three clusters consisting of six, five and two cases were each related to small outbreaks that occurred in a closed setting. Three other clustered cases were linked to a large outbreak that occurred in another institution. Younger patients were more correlated to clustering than older ones. The finding that 45% of the isolates had clustered RFLP patterns suggests that recent transmission is a key factor in the tuberculosis cases in Havana. The IS6110 RFLP typing made it possible to define the occurrence of outbreaks in two closed institutions.

  19. Limits of a rapid identification of common Mediterranean sandflies using polymerase chain reaction-restriction fragment length polymorphism

    Directory of Open Access Journals (Sweden)

    Azzedine Bounamous

    2014-07-01

    Full Text Available A total of 131 phlebotomine Algerian sandflies have been processed in the present study. They belong to the species Phlebotomus bergeroti, Phlebotomus alexandri, Phlebotomus sergenti, Phlebotomus chabaudi, Phlebotomus riouxi, Phlebotomus perniciosus, Phlebotomus longicuspis, Phlebotomus perfiliewi, Phlebotomus ariasi, Phlebotomus chadlii, Sergentomyia fallax, Sergentomyia minuta, Sergentomyia antennata, Sergentomyia schwetzi, Sergentomyia clydei, Sergentomyia christophersi and Grassomyia dreyfussi. They have been characterised by sequencing of a part of the cytochrome b (cyt b, t RNA serine and NADH1 on the one hand and of the cytochrome C oxidase I of the mitochondrial DNA (mtDNA on the other hand. Our study highlights two sympatric populations within P. sergenti in the area of its type-locality and new haplotypes of P. perniciosus and P. longicuspis without recording the specimens called lcx previously found in North Africa. We tried to use a polymerase chain reaction-restriction fragment length polymorphism method based on a combined double digestion of each marker. These method is not interesting to identify sandflies all over the Mediterranean Basin.

  20. Pst I restriction fragment length polymorphism of the human placental alkaline phosphatase gene in normal placentae and tumors

    Energy Technology Data Exchange (ETDEWEB)

    Tsavaler, L.; Penhallow, R.C.; Kam, W.; Sussman, H.H.

    1987-07-01

    The structure of the human placental alkaline phosphatase gene from normal term placentae was studied by restriction enzyme digestion and Southern blot analysis using a cDNA probe to the gene for the placental enzyme. The DNA digests fall into three distinct patterns based on the presence and intensity of an extra 1.1-kilobase Pst I Band. The extra 1.1-kilobase band is present in 9 of 27 placenta samples, and in 1 of these samples the extra band is present at double intensity. No polymorphism was revealed by digestion with restriction enzymes EcoRI, Sma I, BamHI, or Sac I. The extra Pst I-digestion site may lie in a noncoding region of the gene because no correlation was observed between the restriction fragment length polymorphism and the common placental alkaline phosphatase alleles identified by starch gel electrophoresis. In addition, because placental alkaline phosphatase is frequently re-expressed in neoplasms, the authors examined tissue from ovarian, testicular, and endometrial tumors and from BeWo choriocarcinoma cells in culture. The Pst I-DNA digestion patterns from these cells and tissues were identical to those seen in the normal ovary and term placentae. The consistent reproducible digestion patterns seen in DNA from normal and tumor tissue indicate that a major gene rearrangement is not the basis for the ectopic expression of placental alkaline phosphatase in neoplasia.

  1. Restriction fragment length polymorphism (RFLP) of two HLA-B-associated transcripts (BATs) genes in healthy Danes

    DEFF Research Database (Denmark)

    Fugger, L; Morling, N; Ryder, L P;

    1990-01-01

    The restriction fragment length polymorphism (RFLP) of the two human HLA-B-associated transcripts (BATs) genes, BAT1 and BAT2, was investigated using 5 different restriction enzymes and two human BAT1 and BAT2 cDNA probes. Two of the enzymes, NcoI and RsaI, revealed polymorphic patterns which were...... investigated in healthy Danes. The cDNA/restriction enzyme combination BAT1/NcoI identifies polymorphic bands at 12 kb, 8 kb, 2.5 kb, and 1.1 kb, while the BAT2/RsaI combination identifies polymorphic bands at 3.3 kb, 2.7 kb, 2.3 kb, and 0.9 kb. The frequencies of these markers were determined in 90 unrelated...... associated with HLA-B8 and HLA-DR3 while there were no strong associations between the BAT1 and BAT2 markers, but the BAT2/RsaI 2.7 kb marker was strongly positively associated with the TNF alpha/NcoI 5.5 kb marker, which in turn is positively associated with HLA-B8 and HLA-DR3. The negative associations...

  2. Characterization of field strains of infectious laryngotracheitis virus in China by restriction fragment length polymorphism and sequence analysis.

    Science.gov (United States)

    Yan, Zhuanqiang; Li, Shengpeng; Xie, Qingmei; Chen, Feng; Bi, Yingzuo

    2016-01-01

    Nineteen strains of infectious laryngotracheitis virus (ILTV; Gallid herpesvirus 1) were isolated from dead or diseased birds in chicken flocks from different areas of China between 2010 and 2014 and used to investigate ILTV epidemiology. These strains were characterized using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) patterns and sequence analysis of the thymidine kinase (TK) gene. PCR-RFLP analysis showed that the TK gene generated 2 patterns when digested with restriction endonuclease enzymes. Pattern A corresponded to 2 virulent field strains, while pattern B was characteristic of 2 virulent field strains, 15 low pathogenicity field strains, and all vaccine strains. Sequence analysis of the TK gene indicated that the messenger RNA polyadenylation signals could be identified in some isolates where amino acid 252 was threonine, and in those with methionine at that position. The present study has demonstrated that most of the outbreaks of ILT in China were caused either by low virulence strains or by vaccine-related strains, and also emphasizes the importance of reinforcing ILTV surveillance in both vaccinated and nonvaccinated flocks. PMID:26699520

  3. Reverse restriction fragment length polymorphism (RRFLP): A novel technique for genotyping infectious laryngotracheitis virus (ILTV) live attenuated vaccines.

    Science.gov (United States)

    Callison, Scott A; Riblet, Sylva M; Rodríguez-Avila, Andres; García, Maricarmen

    2009-09-01

    A novel technique, the reverse restriction fragment length polymorphism (RRFLP) assay, was developed as a means of detecting specific informative polymorphic sites in the infectious laryngotracheitis virus (ILTV) genome. During the RRFLP procedure, DNA is digested with restriction enzymes targeting an informative polymorphic site and then used as template in a real-time polymerase chain reaction (PCR) with primers flanking the informative region. The analysis of the DeltaC(t) values obtained from digested and undigested template DNA provides the genotype of the DNA. In this study, the RRFLP assay was applied as a method to differentiate between the two types of infectious laryngotracheitis virus attenuated live vaccines. Sequence analysis of ILTV vaccines revealed an informative polymorphic site in the 5'-non-coding region of the infected cell protein (ICP4) gene. Unique AvaI and AlwI restriction enzyme sites were identified in the tissue culture origin and chicken embryo origin attenuated vaccines, respectively. These two informative polymorphic sites were used in a RRFLP assay to genotype rapidly and reproducibly ILTV attenuated live vaccines. PMID:19433109

  4. Intra-specific variability of hindlimb length in the palmate newt: an indicator of population isolation induced by habitat fragmentation?

    Science.gov (United States)

    Trochet, Audrey; Le Chevalier, Hugo; Baillat, Boris; Barthe, Laurent; Pottier, Gilles; Calvez, Olivier; Ribéron, Alexandre; Blanchet, Simon

    2016-04-01

    Habitat fragmentation is one of the main drivers of global amphibian decline. Anthropogenic landscape elements can act as barriers, hindering the dispersal that is essential for maintaining gene flow between populations. Dispersal ability can be influenced by locomotor performance, which in turn can depend on morphological traits, such as hindlimb length (HLL) in amphibians. Here, we tested relationships between HLL and environmental variables-road types, forests and agricultural lands-among 35 sub-populations of palmate newts (Lissotriton helveticus) in southwestern France. We expected roads to select for short-legged newts due to a higher mortality of more mobile individuals (long-legged newts) when crossing roads. Accordingly, short-legged newts were found in the vicinity of roads, whereas long-legged newts were found closer to forests and in ponds close geographically to another water body. HLL in newts was hence influenced by habitat types in a heterogeneous landscape, and could therefore be used as an indicator of population isolation in a meta-population system. PMID:27122009

  5. Analysis of ORF 1 in European porcine reproductive and respiratory syndrome virus by long RT-PCR and restriction fragment length polymorphism (RFLP) analysis

    DEFF Research Database (Denmark)

    Nielsen, H. S.; Storgaard, Torben; Oleksiewicz, M.B.

    2000-01-01

    A rapid method was developed for partial characterization of the replicase-encoding open reading frame 1 (ORF 1) of porcine reproductive and respiratory syndrome virus (PRRSV). It comprised long RT-PCR amplification of 11.1 kb (94%) of ORF 1, followed by restriction fragment length polymorphism...

  6. M protein typing of Thai group A streptococcal isolates by PCR-Restriction fragment length polymorphism analysis

    Directory of Open Access Journals (Sweden)

    Good Michael F

    2005-10-01

    Full Text Available Abstract Background Group A streptococcal (GAS infections can lead to the development of severe post-infectious sequelae, such as rheumatic fever (RF and rheumatic heart disease (RHD. RF and RHD are a major health concern in developing countries, and in indigenous populations of developed nations. The majority of GAS isolates are M protein-nontypeable (MNT by standard serotyping. However, GAS typing is a necessary tool in the epidemiologically analysis of GAS and provides useful information for vaccine development. Although DNA sequencing is the most conclusive method for M protein typing, this is not a feasible approach especially in developing countries. To overcome this problem, we have developed a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP-based assay for molecular typing the M protein gene (emm of GAS. Results Using one pair of primers, 13 known GAS M types showed one to four bands of PCR products and after digestion with Alu I, they gave different RFLP patterns. Of 106 GAS isolates examined from the normal Thai population and from patients with GAS-associated complications including RHD, 95 isolates gave RFLP patterns that corresponded to the 13 known M types. Only 11 isolates gave RFLP patterns that differed from the 13 known M types. These were then analyzed by DNA sequencing and six additional M types were identified. In addition, we found that M93 GAS was the most common M type in the population studied, and is consistent with a previous study of Thai GAS isolates. Conclusion PCR-RFLP analysis has the potential for the rapid screening of different GAS M types and is therefore considerably advantageous as an alternative M typing approach in developing countries in which GAS is endemic.

  7. Molecular characterization of Mycobacterium tuberculosis isolates from Tehran, Iran by restriction fragment length polymorphism analysis and spoligotyping.

    Science.gov (United States)

    Feyisa, Seifu Gizaw; Haeili, Mehri; Zahednamazi, Fatemeh; Mosavari, Nader; Taheri, Mohammad Mohammad; Hamzehloo, Gholamreza; Zamani, Samin; Feizabadi, Mohammad Mehdi

    2016-04-01

    INTRODUCTION Characterization of Mycobacterium tuberculosis (MTB) isolates by DNA fingerprinting has contributed to tuberculosis (TB) control. The aim of this study was to determine the genetic diversity of MTB isolates from Tehran province in Iran. METHODS MTB isolates from 60 Iranian and 10 Afghan TB patients were fingerprinted by standard IS6110-restriction fragment length polymorphism (RFLP) analysis and spoligotyping. RESULTS The copy number of IS6110 ranged from 10-24 per isolate. The isolates were classified into 22 clusters showing ≥ 80% similarity by RFLP analysis. Fourteen multidrug-resistant (MDR) isolates were grouped into 4 IS6110-RFLP clusters, with 10 isolates [71% (95% CI: 45-89%)] in 1 cluster, suggesting a possible epidemiological linkage. Eighteen Iranian isolates showed ≥ 80% similarity with Afghan isolates. There were no strains with identical fingerprints. Spoligotyping of 70 isolates produced 23 distinct patterns. Sixty (85.7%) isolates were grouped into 13 clusters, while the remaining 10 isolates (14.2%) were not clustered. Ural (formerly Haarlem4) (n = 22, 31.4%) was the most common family followed by Central Asian strain (CAS) (n = 18, 25.7%) and T (n = 9, 12.8%) families. Only 1strain was characterized as having the Beijing genotype. Among 60 Iranian and 10 Afghan MTB isolates, 25% (95% CI: 16-37) and 70% (95% CI: 39-89) were categorized as Ural lineage, respectively. CONCLUSIONS A higher prevalence of Ural family MTB isolates among Afghan patients than among Iranian patients suggests the possible transmission of this lineage following the immigration of Afghans to Iran. PMID:27192590

  8. Terminal Restriction Fragment Length Polymorphism for the Identification of Spirorchiid Ova in Tissues from the Green Sea Turtle, Chelonia mydas.

    Science.gov (United States)

    Chapman, Phoebe A; Traub, Rebecca J; Kyaw-Tanner, Myat T; Owen, Helen; Flint, Mark; Cribb, Thomas H; Mills, Paul C

    2016-01-01

    Blood flukes are among the most common disease causing pathogens infecting vertebrates, including humans and some of the world's most globally endangered fauna. Spirorchiid blood flukes are parasites of marine turtles, and are associated with pathology, strandings and mortalities worldwide. Their ova embolize in tissues and incite significant inflammatory responses, however attempts to draw correlations between species and lesions are frustrated by difficulties in identifying ova beyond the genus level. In this study, a newly developed terminal restriction fragment length polymorphism (T-RFLP) method was validated as a tool for differentiating between mixed spirorchiid ova in turtle tissue. Initially, a multiplex PCR was used to differentiate between the five genera of spirorchiid flukes. Following this, PCR was performed using genus/genera-specific fluorescently tagged primer pairs and PCR products digested analysis using restriction endonucleases. Using capillary electrophoresis, this T-RFLP method could differentiate between twelve species and genotypes of spirorchiid flukes in turtles. It was applied to 151 tissue samples and successfully identified the spirorchiid species present. It was found to be more sensitive than visual diagnosis, detecting infections in 28 of 32 tissues that were negative on histology. Spirorchiids were present in 96.7% of tissues tested, with Neospirorchis genotype 2 being the most prevalent, present in 93% of samples. Mixed infections were common, being present in 60.7% of samples tested. The method described here is, to our knowledge, the first use of the T-RFLP technique on host tissues or in an animal ecology context, and describes a significant advancement in the clinical capacity to diagnose a common cause of illness in our environment. It is proven as a sensitive, specific and cost-efficient means of identifying spirorchiid flukes and ova in turtles, with the potential to contribute valuable information to epidemiological and

  9. DNA restriction fragment length polymorphism of HLA-DR2 haplotypes in normal individuals and in patients with rheumatoid arthritis.

    Science.gov (United States)

    Singal, D P; Reid, B; Green, D; Bensen, W G; D'Souza, M

    1990-01-01

    A strong association between HLA-DR4 and rheumatoid arthritis (RA) has been found in a number of populations. In contrast, the incidence of DR2 is decreased in patients with RA, suggesting that this specificity may confer some protection against the disease. A number of subtypes of DR2 have been defined by serology, by responses in mixed lymphocyte culture reaction, and, more recently, by restriction fragment length polymorphism. These subtypes of DR2 are in linkage disequilibrium with different subspecificities of DQw1. It is thus likely that the distribution of these subtypic DR,DQ haplotypes in DR2 positive patients with RA may be important in understanding the genetic basis of susceptibility/resistance to RA. In this paper a study of the subtypes of DR2,DQw1 haplotypes in 18 patients with RA, who required sodium aurothiomalate as a disease remitting drug, and unrelated healthy individuals is reported. Three subtypes of DR2 haplotypes, DRw15 (Dw2),DQw1.2(DQw6), DRw15(Dw12),DQw1.12(DQw6), and DRw16(Dw21),DQw1, AZH (DQw5), were analysed with a cDNA probe for the DQ beta gene. The data show that DR2 positive patients with RA carried either the DRw15(Dw2),DQw6 or DRw15(Dw12),DQw6 haplotype. No patient with RA was positive for the DRw16(Dw21),DQw5 subspecificity. In contrast, six of 29 (21%) normal healthy DR2,DQw1 positive individuals carried the DRw16(Dw21),DQw5 haplotype. These data together with earlier results on the distribution of the DR4,DQw7 haplotype in patients with RA support the hypothesis that DQB1 chain polymorphism may be important in determining susceptibility to severe RA. Images PMID:1969727

  10. Sequence-related amplified polymorphism (SRAP) markers: A potential resource for studies in plant molecular biology1

    OpenAIRE

    Robarts, Daniel W. H.; Wolfe, Andrea D.

    2014-01-01

    In the past few decades, many investigations in the field of plant biology have employed selectively neutral, multilocus, dominant markers such as inter-simple sequence repeat (ISSR), random-amplified polymorphic DNA (RAPD), and amplified fragment length polymorphism (AFLP) to address hypotheses at lower taxonomic levels. More recently, sequence-related amplified polymorphism (SRAP) markers have been developed, which are used to amplify coding regions of DNA with primers targeting open readin...

  11. Identification of Candida species by PCR and restriction fragment length polymorphism analysis of intergenic spacer regions of ribosomal DNA.

    OpenAIRE

    Williams, D W; Wilson, M. J.; Lewis, M. A.; Potts, A J

    1995-01-01

    The PCR was used to amplify a targeted region of the ribosomal DNA from 84 Candida isolates. Unique product sizes were obtained for Candida guilliermondii, Candida (Torulopsis) glabrata, and Candida pseudotropicalis. Isolates of Candida albicans, Candida tropicalis, Candida stellatoidea, Candida parapsilosis, and Candida krusei could be identified following restriction digestion of the PCR products.

  12. Genetic Diversity of Trichomonas vaginalis Clinical Isolates Determined by EcoRI Restriction Fragment Length Polymorphism of Heat-Shock Protein 70 Genes

    OpenAIRE

    Meade, John C.; de Mestral, Jacqueline; Jonathan K Stiles; Secor, W. Evan; Finley, Richard W.; Cleary, John D.; Lushbaugh, William B.

    2009-01-01

    Restriction fragment length polymorphism (RFLP) analysis using a multilocus heat-inducible cytoplasmic heat-shock protein 70 (Hsp70) hybridization probe with EcoRI-digested genomic DNA was used in molecular typing of 129 Trichomonas vaginalis isolates. Results indicate that Trichomonas organisms exhibit considerable polymorphism in their Hsp70 RFLP patterns. Analysis of seven American Type Culture Collection reference strains and 122 clinical isolates, including 84 isolates from Jackson, Miss...

  13. Analysis of the rDNA internal transcribed spacer region of the Fusarium species by polymerase chain reaction-restriction fragment length polymorphism

    OpenAIRE

    Zarrin, Majid; GANJ, FARZANEH; FARAMARZI, SAMA

    2016-01-01

    The Fusarium species are a widely spread phytopathogen identified in an extensive variety of hosts. The Fusarium genus is one of the most heterogeneous fungi and is difficult to classify. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis is a useful method in detection of DNA polymorphism in objective sequences. The aim of the present study was to identify the phylogenetic associations and usefulness of the internal transcribed spacer (ITS) region as a gen...

  14. ISOLATION AND IDENTIFICATION OF cDNA FRAGMENTS AND FULL-LENGTH cDNA DIFFERENTIALLY EXPRESSEDIN HUMAN GLIOBLASTOMA CELL LINE BT-325 VERSUS ALL-TRANS RETINOIC ACID INDUCTION

    Institute of Scientific and Technical Information of China (English)

    金虎林; 胡松年; 李光涛; 涂纯; 袁建刚; 强伯勤

    2000-01-01

    Objective. To investigate the differentiation process of the human glioblastoma cells. Methods. Differential display reverse transcribed-PCR(DDRT-PCR) was used to isolate the genes differentially expressed in control and all-trans retinoic acid treated human glioblastoma cell line BT-325. Routine method of cDNA library screening was performed to clone full-length cDNA. Results. Thirty-six RT-PCR reactions were performed and 64 differentially expressed fragments were recovered, amplified and cloned. Of them,46 ESTs were sequenced and delivered into the GenBank. The homology comparison us-ing BLAST algorithm revealed that 22ESFs are highly homologous with the known genes and many of them play impor-tant roles in the cell differentiation progress. A dot-blot hybridization was conducted to certify the differemiation expres-sion. The result showed that 27 EST clones are expressed at different level in control and all-traus retinoic acid treated BT-325 cells. A full-length cDNA was cloned using the EST-HGBB098.Conclusion. DDRT-PCR was a simple and effective method to segally analyze the differentially expressed genes.

  15. ISOLATION AND IDENTIFICATION OF cDNA FRAGMENTS AND FULL-LENGTH cDNA DIFFERENTIALLY EXPRESSED IN HUMAN GLIOBLASTOMA CELL LINE BT-325 VERSUS ALL-TRANS RETINOIC ACID INDUCTION

    Institute of Scientific and Technical Information of China (English)

    金虎林; 胡松年; 李光涛; 涂纯; 袁建刚; 强伯勤

    2000-01-01

    Objective. To investigate the differentiation process of the human glioblastoma cells. Methods. Differential display reverse transcribed-PCR(DDRT-PCR) was used to isolate the genes differentially expressed in control and all-trans retinoic acid treated human glioblastoma cell line BT-325. Routine method of cDNA library screening was performed to clone full-length cDNA. Results. Thirty-six RT-PCR reactions were performed and 64 differentially expressed fragments were recovered, amplified and cloned. Of them,46 ESTs were sequenced and delivered into the GenBank. The homology comparison us ing BLAST algorithm revealed that 22ESTs are highly homologous with the known genes and many of them play impor tant roles in the cell differentiation progress. A dot-blot hybridization was conducted to certify the differentiation expres sion. The result showed that 27 EST clones are expressed at different level in control and all-trans retinoi c acid treated BT-325 cells. A full-length cDNA was cloned using the ES T-HGBB098. Conclusion. DDRT-PCR was a simple and effective method to serially analyze the differentially expressed genes.

  16. Differentiation of Candida glabrata, C. nivariensis and C. bracarensis based on fragment length polymorphism of ITS1 and ITS2 and restriction fragment length polymorphism of ITS and D1/D2 regions in rDNA

    DEFF Research Database (Denmark)

    Mirhendi, H; Bruun, B; Schønheyder, Henrik Carl;

    2011-01-01

    Different molecular methods for the discrimination of Candida glabrata, C. bracarensis and C. nivariensis were evaluated and the prevalence of these species among Danish blood isolates investigated. Control strains were used to determine fragment length polymorphism in the ITS1, ITS2, ITS1-5.8S...

  17. Fragmented mitochondrial genomes of the rat lice, Polyplax asiatica and Polyplax spinulosa: intra-genus variation in fragmentation pattern and a possible link between the extent of fragmentation and the length of life cycle

    OpenAIRE

    Dong, Wen-Ge; Song, Simon; Jin, Dao-Chao; Guo, Xian-Guo; Shao, Renfu

    2014-01-01

    Background Blood-sucking lice (suborder Anoplura) parasitize eutherian mammals with 67% of the 540 described species found on rodents. The five species of blood-sucking lice that infest humans and pigs have fragmented mitochondrial genomes and differ substantially in the extent of fragmentation. To understand whether, or not, any life-history factors are linked to such variation, we sequenced the mt genomes of Polyplax asiatica and Polyplax spinulosa, collected from the greater bandicoot rat,...

  18. RESTRICTION FRAGMENT LENGTH POLYMORPHISM (RFLP) ANALYSIS OF GENOMIC DNA OF 5 STRAINS OF TRICHINELLA SPIRALIS IN CHINA

    Institute of Scientific and Technical Information of China (English)

    王虹; 张月清; 劳为德; 吴赵永

    1995-01-01

    Five restriction endonucleases were used to digest genomic DNA from 5 isolates of Trichinella spiralis obtained from Changchun,Tianjin,Xian,Henan and Yunnan.All the isolates were secured from pigs ex-cept the Changchun strain which came from dog.The DNA fragments digested by endonuclease were sepa-mted by agarose gel electrophoesis.The DNA fragments digested by endonuclease were sepa-rated by agarose gel electrophoresis.The Changchun is olate had a EcoRI band at 1.12kb and a Dral band at 1.97kb which were unique to this isolate.A cloned specific repetitive DNA sequence(1.12kb) from the Changchun strain was selected to prepare a probe for the Southern blotting of EcoRI restriction DNA frag-ments for the 5 isolates.The 1.12kb hybridizing band did not appear except in the Changchun isolate.These results seem to indicate that there are differences between the isolates obtained from hosts in differ-ent geographical regions.

  19. Identification of planorbids from Venezuela by polymerase chain reaction amplification and restriction fragment length polymorphism of internal transcriber spacer of the RNA ribosomal gene

    Directory of Open Access Journals (Sweden)

    Caldeira Roberta L

    2000-01-01

    Full Text Available Snails of the genus Biomphalaria from Venezuela were subjected to morphological assessment as well as polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP analysis. Morphological identification was carried out by comparison of characters of the shell and the male and female reproductive apparatus. The PCR-RFLP involved amplification of the internal spacer region ITS1 and ITS2 of the RNA ribosomal gene and subsequent digestion of this fragment by the restriction enzymes DdeI, MnlI, HaeIII and MspI. The planorbids were compared with snails of the same species and others reported from Venezuela and present in Brazil, Cuba and Mexico. All the enzymes showed a specific profile for each species, that of DdeI being the clearest. The snails were identified as B. glabrata, B. prona and B. kuhniana.

  20. Analysis of ORF 1 in European porcine reproductive and respiratory syndrome virus by long RT-PCR and restriction fragment length polymorphism (RFLP) analysis

    DEFF Research Database (Denmark)

    Nielsen, H. S.; Storgaard, Torben; Oleksiewicz, M.B.

    2000-01-01

    A rapid method was developed for partial characterization of the replicase-encoding open reading frame 1 (ORF 1) of porcine reproductive and respiratory syndrome virus (PRRSV). It comprised long RT-PCR amplification of 11.1 kb (94%) of ORF 1, followed by restriction fragment length polymorphism...... analysis. The method was used to compare ORF 1 sequences of two divergent European-type PRRSV strains. Our results indicated that the structural and replicase parts of these two strains had evolved at overall similar rates....

  1. Detection and identification of bacterial pathogens of fish in kidney tissue using terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA genes.

    Science.gov (United States)

    Nilsson, William B; Strom, Mark S

    2002-04-01

    We report the application of a nucleic acid-based assay that enables direct detection and identification of bacterial pathogens in fish kidney tissue without the need for bacterial culture. The technique, known as terminal restriction fragment length polymorphism (T-RFLP), employs the polymerase chain reaction (PCR) using a primer pair that targets 2 highly conserved regions of the gene that encodes for the 16S small subunit of the bacterial ribosome. Each primer is 5' labeled with a different fluorescent dye, which results in each terminus of the resulting amplicon having a distinguishable fluorescent tag. The amplicon is then digested with a series of 6 restriction endonucleases, followed by size determination of the 2 labeled terminal fragments by capillary electrophoresis with laser-induced fluorescence detection. Comparison of the lengths of the full set of 12 terminal fragments with those predicted based on analyses of GenBank submissions of 16S sequences leads to presumptive identification of the pathogen to at least the genus, but more typically the species level. Results of T-RFLP analyses of genomic DNA from multiple strains of a number of fish bacterial pathogens are presented. The assay is further demonstrated on fish kidney tissue spiked with a known number of cells of Flavobacterium psychrophilum where a detection limit of ca. 30 CFU mg(-1) of tissue was estimated. A similar detection limit was observed for several other gram-negative pathogens. This procedure was also used to detect Aeromonas salmonicida and Renibacterium salmoninarum in the kidney tissue of 2 naturally infected salmonids. PMID:12033704

  2. Giardia duodenalis in Damascus, Syria: Identification of Giardia genotypes in a sample of human fecal isolates using polymerase chain reaction and restriction fragment length polymorphism analyzing method.

    Science.gov (United States)

    Skhal, Dania; Aboualchamat, Ghalia; Al Nahhas, Samar

    2016-02-01

    Giardia duodenalis is a common gastrointestinal parasite that infects humans and many other mammals. It is most prevalent in many developing and industrialized countries. G. duodenalis is considered to be a complex species. While no morphological distinction among different assemblages exist, it can be genetically differentiated into eight major assemblages: A to H. The aim of this study was to determine the genetic heterogeneity of G. duodenalis in human isolates (a study conducted for the first time in Syria). 40 fecal samples were collected from three different hospitals during the hot summer season of 2014. Extraction of genomic DNA from all Giardia positive samples (based on a microscopic examination) was performed using QIAamp DNA Stool Mini Kit. β-giardin gene was used to differentiate between different Giardia assemblages. The 514 bp fragment was amplified using the Polymerase Chain Reaction method, followed by digestion in HaeIII restriction enzyme. Our result showed that genotype A was more frequent than genotype B, 27/40 (67.5%); 4/40 (10%) respectively. A mixed genotype of A+B was only detected in 9 isolates (22.5%). This is the first molecular study performed on G. duodenalis isolates in Syria in order to discriminate among the different genotypes. Further expanded studies using more genes are needed to detect and identify the Giardia parasite at the level of assemblage and sub-assemblage. PMID:26524628

  3. New restriction fragment length polymorphisms in the cytochrome oxidase I gene facilitate host strain identification of fall armyworm (Lepidoptera: Noctuidae) populations in the southeastern United States.

    Science.gov (United States)

    Nagoshi, Rod N; Meagher, Robert L; Adamczyk, John J; Braman, S Kristine; Brandenburg, Rick L; Nuessly, Gregg

    2006-06-01

    Several restriction sites in the cytochrome oxidase I gene of fall armyworm, Spodoptera frugiperda (J.E. Smith), were identified by sequence analysis as potentially being specific to one of the two host strains. Strain specificity was demonstrated for populations in Florida, Texas, Mississippi, Georgia, and North Carolina, with an AciI and SacI site specific to the rice (Oryjza spp.)-strain and a BsmI and HinfI site joining an already characterized MspI site as diagnostic of the corn (Zea mays L.)-strain. All four of these sites can be detected by digestion of a single 568-bp polymerase chain reaction-amplified fragment, but the use of two enzymes in separate digests was found to provide accurate and rapid determination of strain identity. The effectiveness of this method was demonstrated by the analysis of almost 200 adult and larval specimens from the Mississippi delta region. The results indicated that the corn-strain is likely to be the primary strain infesting cotton (Gossypium spp.) and that an unexpected outbreak of fall armyworm on the ornamental tree Paulownia tomentosa (Thunb.) Sieb. & Zucc. ex Steud. was due almost entirely to the rice-strain. PMID:16813297

  4. Restriction fragment length polymorphism of the 5S-rRNA-NTS region: a rapid and precise method for plant identification.

    Science.gov (United States)

    Bertea, Cinzia Margherita; Gnavi, Giorgio

    2012-01-01

    Molecular genetic methods have several advantages over classical morphological and chemical analyses. The genetic method requires genotype instead than phenotype, therefore PCR-based techniques have been widely used for a rapid identification of plant species, varieties and chemotypes. Recently, the molecular discrimination of some higher plant species has been evaluated using sequences of a 5S-rRNA gene spacer region. The variation in the nontranscribed sequence (NTS) region has been used in a number of plant species for studying intraspecific variation, genome evolution, and phylogenetic reconstruction. Here, we describe a rapid method based on the use of the 5S-rRNA-NTS region as a tool for plant DNA fingerprinting, which combines PCR, sequencing and restriction fragment length polymorphism analyses. PMID:22419491

  5. Genetic Typing of Bovine Viral Diarrhoea Virus (BVDV by Restriction Fragment Length Polymorphism (RFLP and Identification of a New Subtype in Poland

    Directory of Open Access Journals (Sweden)

    Kuta Aleksandra

    2015-04-01

    Full Text Available Restriction fragment length polymorphism (RFLP analysis was developed for genetic typing of Polish strains of bovine viral diarrhoea virus (BVDV. The method was applied using 60 BVDV isolates, which included BVDV genotype 1, subtypes a, b, d, e, f, and g, and genotype 2a. RT-PCR products of the 5’untranslated region (5’UTR were digested using three enzymes. Restriction patterns classified the strains into seven groups, each with a specific and different pattern from other subtypes. These findings were confirmed by nucleotide sequencing and phylogenetic analysis. The results suggest that RFLP analysis is a simple, reliable, and fast genotyping method for BVDV strains in comparison with sequencing. This method can distinguish six subtypes of BVDV-1 including a new subtype 1e, identified exclusively by this method, and it allows differentiation of BVDV-1 from BVDV-2 genotype.

  6. Genetic diversity of Trichomonas vaginalis clinical isolates determined by EcoRI restriction fragment length polymorphism of heat-shock protein 70 genes.

    Science.gov (United States)

    Meade, John C; de Mestral, Jacqueline; Stiles, Jonathan K; Secor, W Evan; Finley, Richard W; Cleary, John D; Lushbaugh, William B

    2009-02-01

    Restriction fragment length polymorphism (RFLP) analysis using a multilocus heat-inducible cytoplasmic heat-shock protein 70 (Hsp70) hybridization probe with EcoRI-digested genomic DNA was used in molecular typing of 129 Trichomonas vaginalis isolates. Results indicate that Trichomonas organisms exhibit considerable polymorphism in their Hsp70 RFLP patterns. Analysis of seven American Type Culture Collection reference strains and 122 clinical isolates, including 84 isolates from Jackson, Mississippi, 18 isolates from Atlanta, Georgia, and 20 isolates from throughout the United States, showed 105 distinct Hsp70 RFLP pattern subtypes for Trichomonas. Phylogenetic analysis of the Hsp70 RFLP data showed that the T. vaginalis isolates were organized into two clonal lineages. These results illustrate the substantial genomic diversity present in T. vaginalis and indicate that a large number of genetically distinct Trichomonas isolates may be responsible for human trichomoniasis in the United States. PMID:19190222

  7. Pst I restriction fragment length polymorphism of human placental alkaline phosphatase gene: Mendelian in segregation and localization of mutation site in the gene

    International Nuclear Information System (INIS)

    The pattern of inheritance of a Pst I restriction fragment length polymorphism (RFLP) of the human placental alkaline phosphatase gene was studied in nine nuclear families by Southern blot hybridization analysis of genomic DNA. The dimorphic RFLP is defined by the presence of allelic fragments 1.0 kilobase and 0.8 kilobase long. The results of this study show that the two alleles of the Pst I RFLP of the placental alkaline phosphatase gene segregate as codominant traits according to Mendelian expectations. For a polymorphism to be useful as a genetic marker the probability that an offspring is informative (PIC) must be at least 0.15. The allelic frequency of the 1.0-kilobase allele is 0.21, which correlates to a probability that an offspring is informative of 0.275 and is indicative of a useful polymorphism. By using probes derived from different regions of the placental alkaline phosphatase cDNA, the mutated Pst I site causing the RFLP was located in the penultimate intron 2497 base pairs downstream from the transcriptional initiation site

  8. Characterization by restriction fragment length polymorphism and sequence analysis of field and vaccine strains of infectious laryngotracheitis virus involved in severe outbreaks.

    Science.gov (United States)

    Chacon, Jorge Luis; Mizuma, Matheus Y; Piantino Ferreira, Antonio J

    2010-12-01

    At the end of 2002 and throughout 2003, there was a severe outbreak of infectious laryngotracheitis (ILT) in an intensive production area of commercial hens in the Sao Paulo State of Brazil. ILT virus was isolated from 28 flocks, and 21 isolates were genotyped by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) using four genes and eight restriction enzymes, and by partial sequencing of the infected cell protein 4 (ICP4) and thymidine kinase (TK) genes. Three groups resulted from the combinations of PCR-RFLP patterns: 19 field isolates formed Group I, and the remaining two isolates together with the chicken embryo origin (CEO) vaccine strains formed Group II. Group III comprised the tissue-culture origin (TCO) vaccine strain by itself. The PCR-RFLP results agreed with the sequencing results of two ICP4 gene fragments. The ICP4 gene sequence analysis showed that the 19 field isolates classified into Group I by RFLP-PCR were identical among themselves, but were different to the TCO and CEO vaccines. The two Group II isolates could not be distinguished from one of the CEO vaccines. The nucleotide and amino acid sequence analyses discriminated between the Brazilian and non-Brazilian isolates, as well as between the TCO and CEO vaccines. Sequence analysis of the TK gene enabled classification of the field isolates (Group I) as virulent and non-vaccine. This work shows that the severe ILT outbreak was caused by a highly virulent, non-vaccine strain. PMID:21154050

  9. Response of soybean rhizosphere communities to human hygiene water addition as determined by community level physiological profiling (CLPP) and terminal restriction fragment length polymorphism (TRFLP) analysis

    Science.gov (United States)

    Kerkhof, L.; Santoro, M.; Garland, J.

    2000-01-01

    In this report, we describe an experiment conducted at Kennedy Space Center in the biomass production chamber (BPC) using soybean plants for purification and processing of human hygiene water. Specifically, we tested whether it was possible to detect changes in the root-associated bacterial assemblage of the plants and ultimately to identify the specific microorganism(s) which differed when plants were exposed to hygiene water and other hydroponic media. Plants were grown in hydroponics media corresponding to four different treatments: control (Hoagland's solution), artificial gray water (Hoagland's+surfactant), filtered gray water collected from human subjects on site, and unfiltered gray water. Differences in rhizosphere microbial populations in all experimental treatments were observed when compared to the control treatment using both community level physiological profiles (BIOLOG) and molecular fingerprinting of 16S rRNA genes by terminal restriction fragment length polymorphism analysis (TRFLP). Furthermore, screening of a clonal library of 16S rRNA genes by TRFLP yielded nearly full length SSU genes associated with the various treatments. Most 16S rRNA genes were affiliated with the Klebsiella, Pseudomonas, Variovorax, Burkholderia, Bordetella and Isosphaera groups. This molecular approach demonstrated the ability to rapidly detect and identify microorganisms unique to experimental treatments and provides a means to fingerprint microbial communities in the biosystems being developed at NASA for optimizing advanced life support operations.

  10. Differential Gene Expression in Response to Papaya ringspot virus Infection in Cucumis metuliferus Using cDNA- Amplified Fragment Length Polymorphism Analysis

    OpenAIRE

    Yu-Tsung Lin; Fuh-Jyh Jan; Chia-Wei Lin; Chien-Hung Chung; Jo-Chu Chen; Shy-Dong Yeh; Hsin-Mei Ku

    2013-01-01

    A better understanding of virus resistance mechanisms can offer more effective strategies to control virus diseases. Papaya ringspot virus (PRSV), Potyviridae, causes severe economical losses in papaya and cucurbit production worldwide. However, no resistance gene against PRSV has been identified to date. This study aimed to identify candidate PRSV resistance genes using cDNA-AFLP analysis and offered an open architecture and transcriptomic method to study those transcripts differentially exp...

  11. Characterization of Mycoplasma hyosynoviae strains by amplified fragment length polymorphism analysis, pulsed-field gel electrophoresis and 16S ribosomal DNA sequencing

    DEFF Research Database (Denmark)

    Kokotovic, Branko; Friis, N.F.; Ahrens, Peter

    2002-01-01

    Mycoplasma hyosynoviae strains from Denmark, Germany, Japan, Sweden, the Netherlands and the UK were examined for variations in the genomic DNA and within the 16S ribosomal RNA (rRNA) gene. Variations in the chromosomal DNA among 57 isolates recovered from the respiratory tract and joints of pigs...... examined for variation within the 16S rRNA gene. Ten field strains possessed the 16S rDNA sequences identical to the type strain, while the remaining six strains had sequences that differed by one to two nucleotides from that obtained from the type strain....

  12. Molecular epidemiology of contagious bovine pleuropneumonia in Tanzania based on amplified fragment length polymorphism and pulsed-field gel electrophoresis analysis

    DEFF Research Database (Denmark)

    Kusiluka, L.J.M.; Ojeniyi, B.; Friis, N.F.;

    2001-01-01

    The genetic diversity of 60 field strains of Mycoplasma mycoides ssp. mycoides, small colony type (M,. mycoides), comprising 56 isolates from cattle in Tanzania, one from Kenya, two from Botswana and one from Portugal, as well as the type (PG1(T)) and vaccine (T-1-SR49) strains, was ivestigated...

  13. TARC: Carlo Rubbia's Energy Amplifier

    CERN Multimedia

    Laurent Guiraud

    1997-01-01

    Transmutation by Adiabatic Resonance Crossing (TARC) is Carlo Rubbia's energy amplifier. This CERN experiment demonstrated that long-lived fission fragments, such as 99-TC, can be efficiently destroyed.

  14. The prevalence of cryptosporidiosis in Turkish children, and geno typing of isolates by nested polymerase chain reaction-restriction fragment length polymorphism

    International Nuclear Information System (INIS)

    Objective was to verify the incidence of cryptosporidiosis among Turkish elementary school students. The study was conducted in the Dept. of Parasitology, Faculty of Medicine, Ege University, Turkey during a 3-month period in 2006. We assessed the fecal samples of 707 children using modified acid-fast and phenol-auramine staining followed by modified Ritchie concentration method. All cryptosporidium species isolates were analysed by nested polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) to differentiate genotypes of the isolates. After the coprological examination, 4 samples were found to be positive for cryptosporidium species oocysts. In the present study, all 4 oocysts were of zoonotic origin and belonged to cryptoporodium parvum genotype 2 indicating that in Turkey the potential sources of human cryptosporidiosis is from animals. The application of genotyping to clinical isolates of cryptosporidium has significantly increased our knowledge and understanding of the distribution and epidemiology of this parasite. The PCR and RFLP techniques represent a more rapid and simple method of genotyping to support epidemiological and clinical investigations than conventional analytical DNA techniques. (author)

  15. Clustering of Beijing genotype Mycobacterium tuberculosis isolates from the Mekong delta in Vietnam on the basis of variable number of tandem repeat versus restriction fragment length polymorphism typing

    Directory of Open Access Journals (Sweden)

    Huyen Mai NT

    2013-02-01

    Full Text Available Abstract Background In comparison to restriction fragment length polymorphism (RFLP typing, variable number of tandem repeat (VNTR typing is easier to perform, faster and yields results in a simple, numerical format. Therefore, this technique has gained recognition as the new international gold standard in typing of Mycobacterium tuberculosis. However, some reports indicated that VNTR typing may be less suitable for Beijing genotype isolates. We therefore compared the performance of internationally standardized RFLP and 24 loci VNTR typing to discriminate among 100 Beijing genotype isolates from the Southern Vietnam. Methods Hundred Beijing genotype strains defined by spoligotyping were randomly selected and typed by RFLP and VNTR typing. The discriminatory power of VNTR and RFLP typing was compared using the Bionumerics software. Results Among 95 Beijing strains available for analysis, 14 clusters were identified comprising 34 strains and 61 unique profiles in 24 loci VNTR typing ((Hunter Gaston Discrimination Index (HGDI = 0.994. 13 clusters containing 31 strains and 64 unique patterns in RFLP typing (HGDI = 0.994 were found. Nine RFLP clusters were subdivided by VNTR typing and 12 VNTR clusters were split by RFLP. Five isolates (5% revealing double alleles or no signal in two or more loci in VNTR typing could not be analyzed. Conclusions Overall, 24 loci VNTR typing and RFLP typing had similar high-level of discrimination among 95 Beijing strains from Southern Vietnam. However, loci VNTR 154, VNTR 2461 and VNTR 3171 had hardly added any value to the level of discrimination.

  16. Restriction Fragment Length Polymorphism Analysis of Large Subunit rDNA of Symbiotic Dinoflagellates from Scleractinian Corals in the Zhubi Coral Reef of the Nansha Islands

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Zooxanthellae are very important for the coral reef ecosystem. The diversity of coral hosts is high in the South China Sea, but the diversity of zooxanthellae has not yet been investigated. We chose the Zhubi Coral Reef of the Nansha Islands as the region to be surveyed in the present study because it represents a typical tropical coral reef of the South China Sea and we investigated zooxanthellae diversity in 10 host scleractinian coral species using polymerase chain reaction (PCR) of the large subunit rRNA and restriction fragment length polymorphism (RFLP) patterns. Pocillopora verrucosa, Acropora pelifera, Acropora millepora, Fungia fungites, Galaxea fascicularis, and Acropora pruinosa harbor Clade C, Goniastrea aspera harbors Clade D, and Acropora formosa harbors Clades D and C. Therefore, the Clade C is the dominant type in the Zhubi Coral Reef of the NanshaIslands. Furthermore, the results of the present also disprove what has been widely accepted, namely that one coral host harbors only one algal symbiont. The coral-algal symbiosis is flexible, which may be an important mechanism for surviving coral bleaching. Meanwhile, on the basis of the results of the present study, we think that Symbiodinium Clade D may be more tolerant to stress than Symbiodinium Clade C.

  17. Double Gene Targeting Multiplex Polymerase Chain Reaction-Restriction Fragment Length Polymorphism Assay Discriminates Beef, Buffalo, and Pork Substitution in Frankfurter Products.

    Science.gov (United States)

    Hossain, M A Motalib; Ali, Md Eaqub; Abd Hamid, Sharifah Bee; Asing; Mustafa, Shuhaimi; Mohd Desa, Mohd Nasir; Zaidul, I S M

    2016-08-17

    Beef, buffalo, and pork adulteration in the food chain is an emerging and sensitive issue. Current molecular techniques to authenticate these species depend on polymerase chain reaction (PCR) assays involving long and single targets which break down under natural decomposition and/or processing treatments. This novel multiplex polymerase chain reaction-restriction fragment length polymorphism assay targeted two different gene sites for each of the bovine, buffalo, and porcine materials. This authentication ensured better security, first through a complementation approach because it is highly unlikely that both sites will be missing under compromised states, and second through molecular fingerprints. Mitochondrial cytochrome b and ND5 genes were targeted, and all targets (73, 90, 106, 120, 138, and 146 bp) were stable under extreme boiling and autoclaving treatments. Target specificity and authenticity were ensured through cross-amplification reaction and restriction digestion of PCR products with AluI, EciI, FatI, and CviKI-1 enzymes. A survey of Malaysian frankfurter products revealed rampant substitution of beef with buffalo but purity in porcine materials. PMID:27501408

  18. Unusual sequence length-dependent gold nanoparticles aggregation of the ssDNA sticky end and its application for enzyme-free and signal amplified colorimetric DNA detection

    Science.gov (United States)

    He, Hongfei; Dai, Jianyuan; Duan, Zhijuan; Zheng, Baozhan; Meng, Yan; Guo, Yong; Dan Xiao

    2016-08-01

    It is known that the adsorption of short single-stranded DNA (ssDNA) on unmodified gold nanoparticles (AuNPs) is much faster than that for long ssDNA, and thus leads to length-dependent AuNPs aggregation after addition of salt, the color of the solutions sequentially changed from red to blue in accordance with the increase of ssDNA length. However, we found herein that the ssDNA sticky end of hairpin DNA exhibited a completely different adsorption behavior compared to ssDNA, an inverse blue-to-red color variation was observed in the colloid solution with the increase of sticky end length when the length is within a certain range. This unusual sequence length-dependent AuNPs aggregation might be ascribed to the effect of the stem of hairpin DNA. On the basis of this unique phenomenon and catalytic hairpin assembly (CHA) based signal amplification, a novel AuNPs-based colorimetric DNA assay with picomolar sensitivity and specificity was developed. This unusual sequence length-dependent AuNPs aggregation of the ssDNA sticky end introduces a new direction for the AuNPs-based colorimetric assays.

  19. Unusual sequence length-dependent gold nanoparticles aggregation of the ssDNA sticky end and its application for enzyme-free and signal amplified colorimetric DNA detection

    Science.gov (United States)

    He, Hongfei; Dai, Jianyuan; Duan, Zhijuan; Zheng, Baozhan; Meng, Yan; Guo, Yong; Dan Xiao

    2016-01-01

    It is known that the adsorption of short single-stranded DNA (ssDNA) on unmodified gold nanoparticles (AuNPs) is much faster than that for long ssDNA, and thus leads to length-dependent AuNPs aggregation after addition of salt, the color of the solutions sequentially changed from red to blue in accordance with the increase of ssDNA length. However, we found herein that the ssDNA sticky end of hairpin DNA exhibited a completely different adsorption behavior compared to ssDNA, an inverse blue-to-red color variation was observed in the colloid solution with the increase of sticky end length when the length is within a certain range. This unusual sequence length-dependent AuNPs aggregation might be ascribed to the effect of the stem of hairpin DNA. On the basis of this unique phenomenon and catalytic hairpin assembly (CHA) based signal amplification, a novel AuNPs-based colorimetric DNA assay with picomolar sensitivity and specificity was developed. This unusual sequence length-dependent AuNPs aggregation of the ssDNA sticky end introduces a new direction for the AuNPs-based colorimetric assays. PMID:27477392

  20. Typing of human adenoviruses in specimens from immunosuppressed patients by PCR-fragment length analysis and real-time quantitative PCR.

    Science.gov (United States)

    Ebner, Karin; Rauch, Margit; Preuner, Sandra; Lion, Thomas

    2006-08-01

    Currently, 51 human adenovirus (AdV) serotypes, which are divided into six species (A to F), are known. AdV infections are a major cause of morbidity and mortality in immunosuppressed individuals, particularly in allogeneic stem cell transplant (SCT) recipients. Any AdV species may cause life-threatening disease, but little information is available on the clinical relevance of individual serotypes. The use of serological testing for serotype identification is limited due to the impaired immune response during the posttransplant period. A new molecular approach to serotype identification is presented here that exploits variable regions within the hexon gene. All serotypes belonging to the species A, B, C, E, and F can be determined by fragment length analysis of a single PCR product. For species C, which is the most prevalent in many geographic regions, an alternative technique based on serotype-specific real-time quantitative PCR was established. Of 135 consecutive pediatric patients screened for AdV infections after allogeneic SCT, 40 tested positive. Detailed analysis revealed the presence of 10 different serotypes; serotypes 1 and 2 from species C (C01 and C02) showed the highest prevalence, accounting for 77% of the AdV-positive cases. Representatives of other species were observed less commonly: serotype A12 in 6.5%; serotype A31 in 4.5%; and B03, B16, C05, C06, D19, and F41 in 2%. The approach to rapid molecular serotype analysis presented here provides a basis for detailed studies on adenovirus epidemiology and on the transmission of nosocomial infections. Moreover, in view of the increasing importance of tailored therapy approaches, serotype identification may in the future have implications for the selection of the most appropriate antiviral treatment. PMID:16891496

  1. A novel quantitative hemolytic assay coupled with restriction fragment length polymorphisms analysis enabled early diagnosis of atypical hemolytic uremic syndrome and identified unique predisposing mutations in Japan.

    Directory of Open Access Journals (Sweden)

    Yoko Yoshida

    Full Text Available For thrombotic microangiopathies (TMAs, the diagnosis of atypical hemolytic uremic syndrome (aHUS is made by ruling out Shiga toxin-producing Escherichia coli (STEC-associated HUS and ADAMTS13 activity-deficient thrombotic thrombocytopenic purpura (TTP, often using the exclusion criteria for secondary TMAs. Nowadays, assays for ADAMTS13 activity and evaluation for STEC infection can be performed within a few hours. However, a confident diagnosis of aHUS often requires comprehensive gene analysis of the alternative complement activation pathway, which usually takes at least several weeks. However, predisposing genetic abnormalities are only identified in approximately 70% of aHUS. To facilitate the diagnosis of complement-mediated aHUS, we describe a quantitative hemolytic assay using sheep red blood cells (RBCs and human citrated plasma, spiked with or without a novel inhibitory anti-complement factor H (CFH monoclonal antibody. Among 45 aHUS patients in Japan, 24% (11/45 had moderate-to-severe (≥50% hemolysis, whereas the remaining 76% (34/45 patients had mild or no hemolysis (<50%. The former group is largely attributed to CFH-related abnormalities, and the latter group has C3-p.I1157T mutations (16/34, which were identified by restriction fragment length polymorphism (RFLP analysis. Thus, a quantitative hemolytic assay coupled with RFLP analysis enabled the early diagnosis of complement-mediated aHUS in 60% (27/45 of patients in Japan within a week of presentation. We hypothesize that this novel quantitative hemolytic assay would be more useful in a Caucasian population, who may have a higher proportion of CFH mutations than Japanese patients.

  2. Mitochondrial restriction fragment length polymorphism (RFLP) and sequence variation among closely related avian species and the genetic characterization of hybrid Dendroica warblers.

    Science.gov (United States)

    Lovette, I J; Bermingham, E; Rohwer, S; Wood, C

    1999-09-01

    To address several interconnected goals, we used mitochondrial DNA (mtDNA) sequences to explore evolutionary relationships among four potentially hybridizing taxa in a North American avian superspecies (Dendroica occidentalis, D. townsendi, D. virens, and D. nigrescens). We first compared the results of a previous restriction fragment length polymorphism (RFLP)-based study with 1453 nucleotides from the mitochondrial cytochrome oxidase subunit I (COI), ATP-synthase 6 (ATPase 6), and ATP-synthase 8 (ATPase 8) genes. Separate phylogenetic analyses of the RFLP and sequence data provided identical and well-supported hierarchical species-level reconstructions that grouped occidentalis and townsendi as sister taxa. We then explored several general features of mitochondrial evolution via a comparison of the RFLP and sequence data sets. Qualitative rate differences that seemed evident in highly autocorrelated comparisons of RFLP vs. sequence pairwise distances were not supported when autocorrelation was removed. We also noted a high variance in corresponding RFLP and sequence distances after the removal of autocorrelation effects. This variance suggests that caution should be used when combining RFLP and sequence-based data in studies that require the large-scale synthesis of divergence estimates drawn from sources employing different molecular techniques. Finally, we used our parallel RFLP and sequence data to design and validate a rapid and inexpensive polymerase chain reaction-RFLP (PCR-RFLP) protocol for determining species-specific mitochondrial haplotypes. This PCR-RFLP technique will be applied in ongoing studies of the occidentalis/townsendi hybrid zone, where the historic and geographical complexity of the interbreeding populations necessitates the genotyping of thousands of individual warblers. PMID:10564448

  3. Characterization of infectious laryngotracheitis virus (ILTV) isolates from commercial poultry by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP).

    Science.gov (United States)

    Oldoni, Ivomar; Rodríguez-Avila, Andrés; Riblet, Sylva; García, Maricarmen

    2008-03-01

    Infectious laryngotracheitis (ILT) is a highly contagious, acute respiratory disease of chickens, of worldwide distribution, that affects growth and egg production and leads to significant economic losses during periodic outbreaks of the disease. Live attenuated vaccines (chicken embryo origin [CEO] and tissue-culture origin [TCO]) have been widely used to control the disease in the United States. It is believed that most of the outbreaks in the United States are caused by vaccine-related isolates that persist in the field and spill over into naïve poultry populations. The objective of this study was to utilize the previously developed polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis to genotype recent ILT virus (ILTV) isolates from commercial poultry. Forty-six samples were collected during January 2006 to April 2007 from five poultry production regions of the United States and were characterized within PCR-RFLP groups III-VI. Sixty-three percent of the samples analyzed were categorized as closely related to the vaccine strains (groups III-V), whereas 33% were categorized as group VI viruses that differed in six and nine PCR-RFLP patterns from the CEO and TCO vaccines; a mixture of group IV and V viruses was detected in two samples (4%). In general, groups V and VI were the most prevalent viruses, found in 52% and 33% of the samples tested respectively. Both types of viruses were detected in vaccinated and nonvaccinated flocks. Although genetically different, both viruses produced severe disease in the field. PMID:18459297

  4. Comparison of human gut microbiota in control subjects and patients with colorectal carcinoma in adenoma: Terminal restriction fragment length polymorphism and next-generation sequencing analyses.

    Science.gov (United States)

    Kasai, Chika; Sugimoto, Kazushi; Moritani, Isao; Tanaka, Junichiro; Oya, Yumi; Inoue, Hidekazu; Tameda, Masahiko; Shiraki, Katsuya; Ito, Masaaki; Takei, Yoshiyuki; Takase, Kojiro

    2016-01-01

    Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in Japan. The etiology of CRC has been linked to numerous factors including genetic mutation, diet, life style, inflammation, and recently, the gut microbiota. However, CRC-associated gut microbiota is still largely unexamined. This study used terminal restriction fragment length polymorphism (T-RFLP) and next-generation sequencing (NGS) to analyze and compare gut microbiota of Japanese control subjects and Japanese patients with carcinoma in adenoma. Stool samples were collected from 49 control subjects, 50 patients with colon adenoma, and 9 patients with colorectal cancer (3/9 with invasive cancer and 6/9 with carcinoma in adenoma) immediately before colonoscopy; DNA was extracted from each stool sample. Based on T-RFLP analysis, 12 subjects (six control and six carcinoma in adenoma subjects) were selected; their samples were used for NGS and species-level analysis. T-RFLP analysis showed no significant differences in bacterial population between control, adenoma and cancer groups. However, NGS revealed that i), control and carcinoma in adenoma subjects had different gut microbiota compositions, ii), one bacterial genus (Slackia) was significantly associated with the control group and four bacterial genera (Actinomyces, Atopobium, Fusobacterium, and Haemophilus) were significantly associated with the carcinoma-in-adenoma group, and iii), several bacterial species were significantly associated with each type (control: Eubacterium coprostanoligens; carcinoma in adenoma: Actinomyces odontolyticus, Bacteroides fragiles, Clostridium nexile, Fusobacterium varium, Haemophilus parainfluenzae, Prevotella stercorea, Streptococcus gordonii, and Veillonella dispar). Gut microbial properties differ between control subjects and carcinoma-in-adenoma patients in this Japanese population, suggesting that gut microbiota is related to CRC prevention and development. PMID:26549775

  5. Randomly Amplified DNA Fingerprinting: A Culmination of DNA Marker Technologies Based on Arbitrarily-Primed PCR Amplification

    OpenAIRE

    Waldron Julie; Peace Cameron P.; Searle Iain R.; Furtado Agnelo; Wade Nick; Findlay Ian; Graham Michael W.; Carroll Bernard J.

    2002-01-01

    Arbitrarily-primed DNA markers can be very useful for genetic fingerprinting and for facilitating positional cloning of genes. This class of technologies is particularly important for less studied species, for which genome sequence information is generally not known. The technologies include Randomly Amplified Polymorphic DNA (RAPD), DNA Amplification Fingerprinting (DAF), and Amplified Fragment Length Polymorphism (AFLP). We have modified the DAF protocol to produce a robust PCR-based DNA ma...

  6. Community analysis of ammonia oxidizer in the oxygen-limited nitritation stage of OLAND system by DGGE of PCR amplified 16S rDNA Fragments and FISH

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dan; ZHANG De-min; LIU Yao-ping; CAO Wen-wei; CHEN Guan-xiong

    2004-01-01

    OLAND(oxygen limited autotrophic nitrification and denitrification) nitrogen removal system was constructed by coupling with oxygen limited nitritation stage and anaerobic ammonium oxidation stage. Ammonia oxidizer, as a kind of key bacteria in N cycle, plays an important role at the oxygen limited nitritation stage of OLAND nitrogen removal system. In this study, specific amplification of 16S rDNA fragment of ammonia oxidizer by nested PCR, separation of mixed PCR samples by denaturing gradient gel electrophoresis(DGGE), and the quantification of ammonia oxidizer by Fluorescence in situ hybridization(FISH) were combined to investigate the shifts of community composition and quantity of ammonia oxidizer of the oxygen limited nitritation stage in OLAND system. It showed that the community composition of ammonia oxidizer changed drastically when dissolved oxygen was decreased gradually, and the dominant ammonia oxidizer of the steady nitrite accumulation stage were completely different from that of the early stage of oxygen limited nitritation identified by DGGE . It was concluded that the Nitrosomonas may be the dominant genus of ammonia oxidizer at the oxygen limited nitritation stage of OLAND system characterized by nested PCR-DGGE and FISH, and the percentage of Nitrosomonas was 72.5% ( 0.8% of ammonia oxidizer at the steady nitrite accumulation stage detected by FISH.

  7. Operational amplifiers

    CERN Document Server

    Dostal, Jiri

    1993-01-01

    This book provides the reader with the practical knowledge necessary to select and use operational amplifier devices. It presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits.Provides the reader with practical knowledge necessary to select and use operational amplifier devices. Presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits

  8. Dynamic changes of telomeric restriction fragment (TRF) lengths in cells during the developmental process from embryos to seedlings and a comparison with the embryonal calli in Ginkgo biloba L.

    Institute of Scientific and Technical Information of China (English)

    Liu Di; Zhang Xiao-mei; Hua Xin; Qiao Nan; Song Han; Lu Hai; Guo Hui-hong; Li Feng-lan

    2007-01-01

    Telomeres are the structures that locate at the terminals of linear eukaryotic chromosomes. They can play essential roles in many cellular processes. The terminal location of Arabidopsis-type TTTAGGG tandem repeats were thought to be highly conserved.The terminal location of Ginkgo biloba L. consisting of TTTAGGG tandem repeats, were confirmed by Bal31 exonuclease degradation and Southern blotting. By comparing telomeric restriction fragment (TRF) lengths at different developmental stages from embryos to seedlings, a fluctuant tendency towards variation was found in these samples. The TRF length of embryos was also compared with that of embryonal calli and an upward trend was discovered in callus culture. The results suggest that there should be a telomerase mechanism or/and ALT mechanism for the maintenance of telomere length.

  9. Pseudo-merohedral twinning and noncrystallographic symmetry in orthorhombic crystals of SIVmac239 Nef core domain bound to different-length TCRζ fragments

    International Nuclear Information System (INIS)

    P212121 crystals of SIV Nef core domain bound to a peptide fragment of the T-cell receptor ζ subunit exhibited noncrystallographic symmetry and nearly perfect pseudo-merohedral twinning simulating tetragonal symmetry. For a different peptide fragment, nontwinned tetragonal crystals were observed but diffracted to lower resolution. The structure was determined after assignment of the top molecular-replacement solutions to various twin or NCS domains followed by refinement under the appropriate twin law. HIV/SIV Nef mediates many cellular processes through interactions with various cytoplasmic and membrane-associated host proteins, including the signalling ζ subunit of the T-cell receptor (TCRζ). Here, the crystallization strategy, methods and refinement procedures used to solve the structures of the core domain of the SIVmac239 isolate of Nef (Nefcore) in complex with two different TCRζ fragments are described. The structure of SIVmac239 Nefcore bound to the longer TCRζ polypeptide (Leu51–Asp93) was determined to 3.7 Å resolution (Rwork = 28.7%) in the tetragonal space group P43212. The structure of SIVmac239 Nefcore in complex with the shorter TCRζ polypeptide (Ala63–Arg80) was determined to 2.05 Å resolution (Rwork = 17.0%), but only after the detection of nearly perfect pseudo-merohedral crystal twinning and proper assignment of the orthorhombic space group P212121. The reduction in crystal space-group symmetry induced by the truncated TCRζ polypeptide appears to be caused by the rearrangement of crystal-contact hydrogen-bonding networks and the substitution of crystallographic symmetry operations by similar noncrystallographic symmetry (NCS) operations. The combination of NCS rotations that were nearly parallel to the twin operation (k, h, −l) and a and b unit-cell parameters that were nearly identical predisposed the P212121 crystal form to pseudo-merohedral twinning

  10. Genetic polymorphism of toll-like receptors 4 gene by polymerase chain reaction-restriction fragment length polymorphisms, polymerase chain reaction-single-strand conformational polymorphism to correlate with mastitic cows

    Directory of Open Access Journals (Sweden)

    Pooja H. Gupta

    2015-05-01

    Full Text Available Aim: An attempt has been made to study the toll-like receptors 4 (TLR4 gene polymorphism from cattle DNA to correlate with mastitis cows. Materials and Methods: In present investigation, two fragments of TLR4 gene named T4CRBR1 and T4CRBR2 of a 316 bp and 382 bp were amplified by polymerase chain reaction (PCR, respectively from Kankrej (22 and Triple cross (24 cattle. The genetic polymorphisms in the two populations were detected by a single-strand conformational polymorphism in the first locus and by digesting the fragments with restriction endonuclease Alu I in the second one. Results: Results showed that both alleles (A and B of two loci were found in all the two populations and the value of polymorphism information content indicated that these were highly polymorphic. Statistical results of χ2 test indicated that two polymorphism sites in the two populations fit with Hardy–Weinberg equilibrium (p˂0.05. Meanwhile, the effect of polymorphism of TLR4 gene on the somatic cell score (SCS indicated the cattle with allele a in T4CRBR1 showed lower SCS than that of allele B (p<0.05. Thus, the allele A might play an important role in mastitis resistance in cows. Conclusion: The relationship between the bovine mastitis trait and the polymorphism of TLR4 gene indicated that the bovine TLR4 gene may play an important role in mastitis resistance.

  11. Discrimination of press fit candidate microorganism (Enterobacter cloacae, Bacillus licheniformis) by restriction fragment length polymorphic analysis of the 16SrRNA gene; 16S rRNA idenshi no sengen danpen kchotakei kaiseki niyoru atsunyukoho biseibutsu (Enterobacter cloacae, Bacillus licheni-formis) no shikibetsu

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, Kazuhiro; Tanaka, Shinji; Otsuka, Makiko; Ichimura, Naoya; Yonebayashi, Eiji; Enomoto, Heiji

    1999-09-01

    In MeOH viewed as one of the improvement method for recovery of the petroleum with hope, the development of discrimination technique of press fit candidate microorganism and oil reservoir resident microorganism which exists in the test object oil reservoir was tried in order to monitor the survival situation of the microorganism which inserted in the oil reservoir under pressure. 16S rRNA amplified by the PCR using the universal primer The microorganism that it cut off the gene at restriction enzyme HhaI,MspI, AluI and inhabits oil reservoir water and oil reservoir rock in the object oil reservoir by ( necessarily TaqI ) and restriction fragment length polymorphic analysis was classified. As the result, the effectiveness of the this PCR-RFLP method was indicated the microorganism which showed RFLP pattern which is identical with the press fit candidate microorganism in the oil reservoir resident microorganism for the discrimination of the press fit candidate microorganism without existing. And, it was indicated that the this PCR-RFLP method was effective for the investigation of oil reservoir resident microbial community which can positively utilize source of nutrition inserted to oil reservoir with the press fit candidate microorganism under pressure, and it was possible to grasp oil reservoir resident microorganism to be especially considered in MEOR. (translated by NEDO)

  12. Differentiation of canine distemper virus isolates in fur animals from various vaccine strains by reverse transcription-polymerase chain reaction-restriction fragment length polymorphism according to phylogenetic relations in china

    Directory of Open Access Journals (Sweden)

    Zhao Jianjun

    2011-02-01

    Full Text Available Abstract In order to effectively identify the vaccine and field strains of Canine distemper virus (CDV, a new differential diagnostic test has been developed based on reverse transcription-polymerase chain reaction (RT-PCR and restriction fragment length polymorphism (RFLP. We selected an 829 bp fragment of the nucleoprotein (N gene of CDV. By RFLP analysis using BamHI, field isolates were distinguishable from the vaccine strains. Two fragments were obtained from the vaccine strains by RT-PCR-RFLP analysis while three were observed in the field strains. An 829 nucleotide region of the CDV N gene was analyzed in 19 CDV field strains isolated from minks, raccoon dogs and foxes in China between 2005 and 2007. The results suggest this method is precise, accurate and efficient. It was also determined that three different genotypes exist in CDV field strains in fur animal herds of the north of China, most of which belong to Asian type. Mutated field strains, JSY06-R1, JSY06-R2 and JDH07-F1 also exist in Northern China, but are most closely related to the standard virulent strain A75/17, designated in Arctic and America-2 genetype in the present study, respectively.

  13. Variation of clonal, mesquite-associated rhizobial and bradyrhizobial populations from surface and deep soils by symbiotic gene region restriction fragment length polymorphism and plasmid profile analysis.

    Science.gov (United States)

    Thomas, P M; Golly, K F; Zyskind, J W; Virginia, R A

    1994-04-01

    Genetic characteristics of 14 Rhizobium and 9 Bradyrhizobium mesquite (Prosopis glandulosa)-nodulating strains isolated from surface (0- to 0.5-m) and deep (4- to 6-m) rooting zones were determined in order to examine the hypothesis that surface- and deep-soil symbiont populations were related but had become genetically distinct during adaptation to contrasting soil conditions. To examine genetic diversity, Southern blots of PstI-digested genomic DNA were sequentially hybridized with the nodDABC region of Rhizobium meliloti, the Klebsiella pneumoniae nifHDK region encoding nitrogenase structural genes, and the chromosome-localized ndvB region of R. meliloti. Plasmid profile and host plant nodulation assays were also made. Isolates from mesquite nodulated beans and cowpeas but not alfalfa, clover, or soybeans. Mesquite was nodulated by diverse species of symbionts (R. meliloti, Rhizobium leguminosarum bv. phaseoli, and Parasponia bradyrhizobia). There were no differences within the groups of mesquite-associated rhizobia or bradyrhizobia in cross-inoculation response. The ndvB hybridization results showed the greatest genetic diversity among rhizobial strains. The pattern of ndvB-hybridizing fragments suggested that surface and deep strains were clonally related, but groups of related strains from each soil depth could be distinguished. Less variation was found with nifHDK and nodDABC probes. Large plasmids (>1,500 kb) were observed in all rhizobia and some bradyrhizobia. Profiles of plasmids of less than 1,000 kb were related to the soil depth and the genus of the symbiont. We suggest that interacting selection pressures for symbiotic competence and free-living survival, coupled with soil conditions that restrict genetic exchange between surface and deep-soil populations, led to the observed patterns of genetic diversity. PMID:16349226

  14. Characterization of infectious laryngotracheitis virus isolates from the US by polymerase chain reaction and restriction fragment length polymorphism of multiple genome regions.

    Science.gov (United States)

    Oldoni, Ivomar; García, Maricarmen

    2007-04-01

    Infectious laryngotracheitis (ILT) is an acute viral respiratory disease, primarily of chickens. Economic losses attributable to ILT affect many poultry-producing areas throughout the United States (US) and the world. Despite efforts to control the disease by vaccination, prolonged epidemics of ILT remain a threat to the poultry industry. Earlier epidemiological and molecular evidence indicated that outbreaks in the US are caused by vaccine-related strains. In this study, polymerase chain reaction and restriction fragment polymorphism (PCR-RFLP) of four genome regions was utilized to characterize 25 isolates from commercial poultry and backyard flocks from the US. Combinations of PCR-RFLP patterns classified the ILT virus isolates into nine groups. Backyard flock isolates were categorized in three separate groups. The ILT virus US Department of Agriculture (USDA) reference strain and the tissue culture origin (TCO) vaccine strain were categorized into two separate groups. Twenty-two isolates from commercial poultry were categorized into four groups: one group, of six isolates, showed patterns identical to the chicken embryo origin (CEO) vaccines; a second group, of nine isolates, differed in only one pattern from the CEO vaccines; a third group, of two isolates, differed in only one pattern from the TCO vaccine; a fourth group, of five isolates, differed in six and nine patterns from the CEO and TCO vaccines, respectively. Results obtained from this study clearly demonstrated that most of the commercial poultry isolates (17 of 22 isolates) were closely related to the vaccine strains. However, isolates different to the vaccine strains were also identified in commercial poultry. PMID:17479379

  15. Research on microbial community structure of cholesterol calculus patients by terminal restriction fragment length polymorphism%胆固醇结石患者胆囊细菌的T-RFLP研究

    Institute of Scientific and Technical Information of China (English)

    叶吉云; 李洱花; 刘云霞; 田大广; 高波

    2013-01-01

    目的应用T-RFLP分析胆固醇结石中微生物群落结构。方法应用末端标记限制性片段长度多态性(Terminal Restriction Fragment Length Polymorphism,T-RFLP)和克隆文库分析,以微生物群落16S rRNA基因(16S rDNA)为目标,对8例常规细菌培养阴性的纯胆固醇患者胆囊结石和胆汁中的微生物群落结构进行解析和比较。结果发现8例纯胆固醇结石患者胆汁中未找到细菌存在的证据,结石中细菌16S rDNA阳性率为37.5%(3/8),细菌16S rDNA片段测序表明细菌群落与肠杆菌科和微球菌科的微生物有较高的相似性,同时细菌群落中检出了大量的未培养微生物(Uncultured bacterium clone)。结论运用T-RFLP方法分析16S rDNA克隆片段能够有效评估纯胆固醇结石中的细菌群落结构的多样性。%Objective To analysis of microbial community structure in cholesterol calculus by T-RFLP (Terminal Restriction Fragment Length Polymorphism). Methods Small subunit rRNA gene (16S rDNA) was retrieved from 8 patients' gallstone and bile with cholesterol calculus. The microbial community structure of these cholesterol calculus patients' gallstone and bile were investigated by T-RFLP and clone libraries approaches. Results There was no bacterium found in bile from 8 patients with cholesterol calculus. The positive rate of bacterial 16S rDNA in stone was 37.5%(3/8). Bacterial 16S rDNA sequencing fragments showed that microbial community and Enterobacteriaceae and Micrococcaceae microorganisms had high similarity. Meanwhile, there were detected a number of uncultured bacterium from microbial community. Conclusion Analysis of 16S rDNA cloned fragment could effectively evaluate the diversity of bacterial community structure by T-RFLP method in cholesterol stone.

  16. A truncated fragment of Ov-ASP-1 consisting of the core pathogenesis-related-1 (PR-1) domain maintains adjuvanticity as the full-length protein.

    Science.gov (United States)

    Guo, Jingjing; Yang, Yi; Xiao, Wenjun; Sun, Weilai; Yu, Hong; Du, Lanying; Lustigman, Sara; Jiang, Shibo; Kou, Zhihua; Zhou, Yusen

    2015-04-15

    The Onchocerca volvulus activation-associated secreted protein-1 (Ov-ASP-1) has good adjuvanticity for a variety of antigens and vaccines, probably due to its ability activate antigen-processing cells (APCs). However, the functional domain of Ov-ASP-1 as an adjuvant is not clearly defined. Based on the structural prediction of this protein family, we constructed a 16-kDa recombinant protein of Ov-ASP-1 that contains only the core pathogenesis-related-1 (PR-1) domain (residues 10-153), designated ASPPR. We found that ASPPR exhibits adjuvanticity similar to that of the full-length Ov-ASP-1 (residues 10-220) for various antigens, including ovalbumin (OVA), HBsAg protein antigen, and the HIV peptide 5 (Pep5) antigen, but it is more suitable for vaccine design in ASPPR-antigen fusion proteins, and more stable in PBS than Ov-ASP-1 stored at -70 °C. These results suggest that ASPPR might be the functional region of Ov-ASP-1 as an adjuvant, and therefore could be developed as an adjuvant for human use. PMID:25736195

  17. Diversity of nitrite reductase (nirK and nirS) gene fragments in forested upland and wetland soils

    DEFF Research Database (Denmark)

    Priemé, Anders; Braker, Gesche; Tiedje, James M.

    2002-01-01

    The genetic heterogeneity of nitrite reductase gene (nirK and nirS) fragments from denitrifying prokaryotes in forested upland and marsh soil was investigated using molecular methods. nirK gene fragments could be amplified from both soils, whereas nirS gene fragments could be amplified only from...... the marsh soil. PCR products were cloned and screened by restriction fragment length polymorphism (RFLP), and representative fragments were sequenced. The diversity of nirK clones was lower than the diversity of nirS clones. Among the 54 distinct nirK RFLP patterns identified in the two soils, only...... one pattern was found in both soils and in each soil two dominant groups comprised >35% of all clones. No dominance and few redundant patterns were seen among the nirS clones. Phylogenetic analysis of deduced amino acids grouped the nirK sequences into five major clusters, with one cluster...

  18. Identification and phyletic evolution analysis of Proteus mirabilis strains by PCR and restriction fragment length polymorphism of 16S-23S rRNA gene intergenic spacer region%16S-23S rRNA基因间隔序列PCR及RFLP对奇异变形杆菌分离株的鉴别与系统发育分析

    Institute of Scientific and Technical Information of China (English)

    崔国林; 朱瑞良; 左雪梅; 钟世勋; 杨世发; 梁漫飞; 孙婧; 刘静静

    2013-01-01

    根据临床常见致病菌16S-23S rRNA基因间隔序列(ISR)两端的16S及23S rRNA保守序列设计PCR扩增的通用引物,对9株奇异变形杆菌和6株相近菌株应用通用引物PCR扩增16S-23S rRNA ISR序列.通过PCR长度多态性比较、RFLP分析以及部分序列测序比较,分析鉴别奇异变形杆菌.结果显示,PCR长度多态性可以将奇异变形杆菌同其余菌种进行区分;RFLP分析可以将所有试验菌种进行区分;部分序列测序可以对奇异变形杆菌进行分型.由此表明,16S 23S rRNA ISR序列PCR及RFLP分析可以简单、快速、准确的鉴定奇异变形杆菌.%To establish a new method to identify Proteus mirabilis strains, according to the conserved sequences of 16S and 23S which located on both ends of the clinical common pathogenic bacteria 16S-23S rRNA gene intergenic spacer region (ISR),a pair of universal primers was designed. Nine Proteus mirabilis strains and six similar bacteria strains were amplified by PCR and identified by the PCR length polymorphism comparison,restriction fragment length polymorphism (RFLP) analysis and partial sequences sequencing. The result showed that Proteus mirabilis strains could be discriminated from other similar bacteria strains by PCR length polymorphism comparison,all of test organism could be discriminated by RFLP and Proteus mirabilis strains could be typed by partial sequences sequencing. The result indicated that the identification method based on the 16S-23S rRNA ISR, using PCR and PCR-RFLP,is very suitable for the rapid low-cost identification and discrimination of Proteus mirabilis strains from other phylogenetically related bacteria strains.

  19. Dielectric waveguide amplifiers and lasers

    NARCIS (Netherlands)

    Pollnau, M.

    2014-01-01

    The performance of semiconductor amplifiers and lasers has made them the preferred choice for optical gain on a micro-chip. In the past few years, we have demonstrated that also rare-earth-ion-doped dielectric waveguides show remarkable performance, ranging from a small-signal gain per unit length o

  20. In Vivo Dopamine Efflux is Decreased in Striatum of both Fragment (R6/2 and Full-length (YAC128 Transgenic Mouse Models of Huntington’s Disease

    Directory of Open Access Journals (Sweden)

    Joshua W Callahan

    2011-07-01

    Full Text Available Huntington’s disease (HD is characterized by alterations within the corticostriatal circuitry. The striatum is innervated by a dense array of dopaminergic (DA terminals and these DA synapses are critical to the proper execution of motor functions. As motor disturbances are prevalent in HD we examined DA neurotransmission in the striatum in transgenic (tg murine models of HD. We used in vivo microdialysis to compare extracellular concentrations of striatal DA in both a fragment (R6/2 model, which displays a rapid and severe phenotype, and a full-length (YAC128 model that expresses a more progressive phenotype. Extracellular striatal DA concentrations were significantly reduced in R6/2 mice and decreased concomitantly with age-dependent increasing motor impairments on the rotarod task (7, 9, and 11 weeks. In a sample of 11-week-old R6/2 mice, we also measured tissue concentrations of striatal DA and found that total levels of DA were significantly depleted. However, the loss of total DA content (<50% was insufficient to account for the full extent of DA depletion in the extracellular fluid (ECF (~75%. We also observed a significant reduction in extracellular DA concentrations in the striatum of 7-month-old YAC128 mice. In a separate set of experiments, we applied d-amphetamine (AMPH (10 μm locally into the striatum to stimulate the release of intracellular DA into the ECF. The AMPH-induced increase in extracellular DA levels was significantly blunted in 9-week-old R6/2 mice. There also was a decrease in AMPH-stimulated DA efflux in 7-month-old YAC128 mice in comparison to WT controls, although the effect was milder. In the same cohort of 7-month-old YAC128 mice we observed a significant reduction in the total locomotor activity in response to systemic AMPH (2 mg/kg. Our data demonstrate that extracellular DA release is attenuated in both a fragment and full-length tg mouse model of HD and support the concept of DA involvement in aspects of the

  1. Low cost instrumentation amplifier

    Science.gov (United States)

    Sturman, J. C.

    1974-01-01

    Amplifier can be used for many applications requiring high input impedance and common mode rejection, low drift, and gain accuracy on order of one percent. Performance of inexpensive amplifier approaches that of some commercial instrumentation amplifiers in many specifications.

  2. A mechanism of gene amplification driven by small DNA fragments.

    Directory of Open Access Journals (Sweden)

    Kuntal Mukherjee

    Full Text Available DNA amplification is a molecular process that increases the copy number of a chromosomal tract and often causes elevated expression of the amplified gene(s. Although gene amplification is frequently observed in cancer and other degenerative disorders, the molecular mechanisms involved in the process of DNA copy number increase remain largely unknown. We hypothesized that small DNA fragments could be the trigger of DNA amplification events. Following our findings that small fragments of DNA in the form of DNA oligonucleotides can be highly recombinogenic, we have developed a system in the yeast Saccharomyces cerevisiae to capture events of chromosomal DNA amplification initiated by small DNA fragments. Here we demonstrate that small DNAs can amplify a chromosomal region, generating either tandem duplications or acentric extrachromosomal DNA circles. Small fragment-driven DNA amplification (SFDA occurs with a frequency that increases with the length of homology between the small DNAs and the target chromosomal regions. SFDA events are triggered even by small single-stranded molecules with as little as 20-nt homology with the genomic target. A double-strand break (DSB external to the chromosomal amplicon region stimulates the amplification event up to a factor of 20 and favors formation of extrachromosomal circles. SFDA is dependent on Rad52 and Rad59, partially dependent on Rad1, Rad10, and Pol32, and independent of Rad51, suggesting a single-strand annealing mechanism. Our results reveal a novel molecular model for gene amplification, in which small DNA fragments drive DNA amplification and define the boundaries of the amplicon region. As DNA fragments are frequently found both inside cells and in the extracellular environment, such as the serum of patients with cancer or other degenerative disorders, we propose that SFDA may be a common mechanism for DNA amplification in cancer cells, as well as a more general cause of DNA copy number variation

  3. A mechanism of gene amplification driven by small DNA fragments.

    Science.gov (United States)

    Mukherjee, Kuntal; Storici, Francesca

    2012-01-01

    DNA amplification is a molecular process that increases the copy number of a chromosomal tract and often causes elevated expression of the amplified gene(s). Although gene amplification is frequently observed in cancer and other degenerative disorders, the molecular mechanisms involved in the process of DNA copy number increase remain largely unknown. We hypothesized that small DNA fragments could be the trigger of DNA amplification events. Following our findings that small fragments of DNA in the form of DNA oligonucleotides can be highly recombinogenic, we have developed a system in the yeast Saccharomyces cerevisiae to capture events of chromosomal DNA amplification initiated by small DNA fragments. Here we demonstrate that small DNAs can amplify a chromosomal region, generating either tandem duplications or acentric extrachromosomal DNA circles. Small fragment-driven DNA amplification (SFDA) occurs with a frequency that increases with the length of homology between the small DNAs and the target chromosomal regions. SFDA events are triggered even by small single-stranded molecules with as little as 20-nt homology with the genomic target. A double-strand break (DSB) external to the chromosomal amplicon region stimulates the amplification event up to a factor of 20 and favors formation of extrachromosomal circles. SFDA is dependent on Rad52 and Rad59, partially dependent on Rad1, Rad10, and Pol32, and independent of Rad51, suggesting a single-strand annealing mechanism. Our results reveal a novel molecular model for gene amplification, in which small DNA fragments drive DNA amplification and define the boundaries of the amplicon region. As DNA fragments are frequently found both inside cells and in the extracellular environment, such as the serum of patients with cancer or other degenerative disorders, we propose that SFDA may be a common mechanism for DNA amplification in cancer cells, as well as a more general cause of DNA copy number variation in nature. PMID

  4. Jet fragmentation

    International Nuclear Information System (INIS)

    The paper reviews studies on jet fragmentation. The subject is discussed under the topic headings: fragmentation models, charged particle multiplicity, bose-einstein correlations, identified hadrons in jets, heavy quark fragmentation, baryon production, gluon and quark jets compared, the string effect, and two successful models. (U.K.)

  5. Genetic Diversity of Human Pathogenic Members of the Fusarium oxysporum Complex Inferred from Multilocus DNA Sequence Data and Amplified Fragment Length Polymorphism Analyses: Evidence for the Recent Dispersion of a Geographically Widespread Clonal Lineage and Nosocomial Origin

    OpenAIRE

    O'Donnell, Kerry; Sutton, Deanna A.; Rinaldi, Michael G.; Magnon, Karen C.; Cox, Patricia A.; Revankar, Sanjay G.; Sanche, Stephen; Geiser, David M.; Juba, Jean H.; van Burik, Jo-Anne H.; Padhye, Arvind; Anaissie, Elias J.; Francesconi, Andrea; Thomas J Walsh; Robinson, Jody S.

    2004-01-01

    Fusarium oxysporum is a phylogenetically diverse monophyletic complex of filamentous ascomycetous fungi that are responsible for localized and disseminated life-threatening opportunistic infections in immunocompetent and severely neutropenic patients, respectively. Although members of this complex were isolated from patients during a pseudoepidemic in San Antonio, Tex., and from patients and the water system in a Houston, Tex., hospital during the 1990s, little is known about their genetic re...

  6. Genetic diversity of nifH gene sequences in Paenibacillus azotofixans strains and soil samples analyzed by denaturing gradiënt gel electrophoresis of PCR-amplified gene fragments

    NARCIS (Netherlands)

    Rosado, A.S.; Duarte, G.F.; Seldin, L.; Elsas, van J.D.

    1998-01-01

    The diversity of dinitrogenase reductase gene (nifH) fragments in Paenibacillus azotofixans strains was investigated by using molecular methods. The partial nifH gene sequences of eight P. azotofixans strains, as well as one strain each of the close relatives Paenibacillus durum, Paenibacillus polym

  7. Gain ranging amplifier

    International Nuclear Information System (INIS)

    A gain ranging amplifier system is provided for use in the acquisition of data. Voltage offset compensation is utilized to correct errors in the gain ranging amplifier system caused by thermal drift and temperature dependent voltage offsets, both of which are associated with amplifiers in the gain ranging amplifier system

  8. Novel enzyme immunoassay and optimized DNA extraction for the detection of polymerase-chain-reaction-amplified viral DNA from paraffin-embedded tissue.

    OpenAIRE

    Merkelbach, S.; Gehlen, J.; Handt, S.; Füzesi, L

    1997-01-01

    Four different DNA extraction methods were compared to determine their ability to provide DNA for amplification of viral sequences from paraffin-embedded human tissue samples by polymerase chain reaction (PCR). The suitability of extraction methods was assessed using parameters like DNA yield, length of recovered DNA fragments, and duration. Furthermore, the efficiency of amplifying a human single-copy gene, the beta-globin gene, from DNA samples was tested. The best preservation of DNA molec...

  9. Determination of genotypic diversity of Mycobacterium avium subspecies from human and animal origins by mycobacterial interspersed repetitive-unit-variable-number tandem-repeat and IS1311 restriction fragment length polymorphism typing methods.

    Science.gov (United States)

    Radomski, Nicolas; Thibault, Virginie C; Karoui, Claudine; de Cruz, Krystel; Cochard, Thierry; Gutiérrez, Cristina; Supply, Philip; Biet, Frank; Boschiroli, María Laura

    2010-04-01

    Members of the Mycobacterium avium complex (MAC) are ubiquitous bacteria that can be found in water, food, and other environmental samples and are considered opportunistic pathogens for numerous animal species, mainly birds and pigs, as well as for humans. We have recently demonstrated the usefulness of a PCR-based mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) typing for the molecular characterization of M. avium subsp. paratuberculosis and M. avium strains exclusively isolated from AIDS patients. In the present study we extended our analysis, based on eight MIRU-VNTR markers, to a strain collection comprehensively comprising the other M. avium subspecies, including M. avium subsp. avium, M. avium subsp. hominissuis, and M. avium subsp. silvaticum, isolated from numerous animal species, HIV-positive and HIV-negative humans, and environmental sources. All strains were fully typeable, with the discriminatory index being 0.885, which is almost equal to that obtained by IS1311 restriction fragment length polymorphism (RFLP) typing as a reference. In contrast to IS1311 RFLP typing, MIRU-VNTR typing was able to further discriminate M. avium subsp. avium strains. MIRU-VNTR alleles strongly associated with or specific for M. avium subspecies were detected in several markers. Moreover, the MIRU-VNTR typing-based results were consistent with a scenario of the independent evolution of M. avium subsp. avium/M. avium subsp. silvaticum and M. avium subsp. paratuberculosis from M. avium subsp. hominissuis, previously proposed on the basis of multilocus sequence analysis. MIRU-VNTR typing therefore appears to be a convenient typing method capable of distinguishing the three main subspecies and strains of the complex and providing new epidemiological knowledge on MAC. PMID:20107094

  10. Amplified Quantum Transforms

    OpenAIRE

    Cornwell, David

    2014-01-01

    In this thesis we investigate two new Amplified Quantum Transforms. In particular we create and analyze the Amplified Quantum Fourier Transform (Amplified-QFT) and the Amplified-Haar Wavelet Transform. First, we provide a brief history of quantum mechanics and quantum computing. Second, we examine the Amplified-QFT in detail and compare it against the Quantum Fourier Transform (QFT) and Quantum Hidden Subgroup (QHS) algorithms for solving the Local Period Problem. We calculate the probabiliti...

  11. Nuclear fragmentation

    International Nuclear Information System (INIS)

    An introduction to nuclear fragmentation, with emphasis in percolation ideas, is presented. The main theoretical models are discussed and as an application, the uniform expansion approximation is presented and the statistical multifragmentation model is used to calculate the fragment energy spectra. (L.C.)

  12. Digital fragment analysis of short tandem repeats by high-throughput amplicon sequencing.

    Science.gov (United States)

    Darby, Brian J; Erickson, Shay F; Hervey, Samuel D; Ellis-Felege, Susan N

    2016-07-01

    High-throughput sequencing has been proposed as a method to genotype microsatellites and overcome the four main technical drawbacks of capillary electrophoresis: amplification artifacts, imprecise sizing, length homoplasy, and limited multiplex capability. The objective of this project was to test a high-throughput amplicon sequencing approach to fragment analysis of short tandem repeats and characterize its advantages and disadvantages against traditional capillary electrophoresis. We amplified and sequenced 12 muskrat microsatellite loci from 180 muskrat specimens and analyzed the sequencing data for precision of allele calling, propensity for amplification or sequencing artifacts, and for evidence of length homoplasy. Of the 294 total alleles, we detected by sequencing, only 164 alleles would have been detected by capillary electrophoresis as the remaining 130 alleles (44%) would have been hidden by length homoplasy. The ability to detect a greater number of unique alleles resulted in the ability to resolve greater population genetic structure. The primary advantages of fragment analysis by sequencing are the ability to precisely size fragments, resolve length homoplasy, multiplex many individuals and many loci into a single high-throughput run, and compare data across projects and across laboratories (present and future) with minimal technical calibration. A significant disadvantage of fragment analysis by sequencing is that the method is only practical and cost-effective when performed on batches of several hundred samples with multiple loci. Future work is needed to optimize throughput while minimizing costs and to update existing microsatellite allele calling and analysis programs to accommodate sequence-aware microsatellite data. PMID:27386092

  13. Portable musical instrument amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Christian, David E. (Danbury, CT)

    1990-07-24

    The present invention relates to a musical instrument amplifier which is particularly useful for electric guitars. The amplifier has a rigid body for housing both the electronic system for amplifying and processing signals from the guitar and the system's power supply. An input plug connected to and projecting from the body is electrically coupled to the signal amplifying and processing system. When the plug is inserted into an output jack for an electric guitar, the body is rigidly carried by the guitar, and the guitar is operatively connected to the electrical amplifying and signal processing system without use of a loose interconnection cable. The amplifier is provided with an output jack, into which headphones are plugged to receive amplified signals from the guitar. By eliminating the conventional interconnection cable, the amplifier of the present invention can be used by musicians with increased flexibility and greater freedom of movement.

  14. Amplifier for nuclear spectrometry

    International Nuclear Information System (INIS)

    The spectroscopy amplifier model AE-020 is designed to adjust suitable the pulses coming from nuclear radiation detectors. Due to is capacity and specifications, the amplifier can be used together with high and medium resolution spectroscopy system

  15. [Analysis of full-length gene sequence of rabies vaccine virus aG strain].

    Science.gov (United States)

    Li, Jia; Cao, Shou-Chun; Shi, Lei-Tai; Wu, Xiao-Hong; Liu, Jing-Hua; Wang, Yun-Peng; Tang, Jian-Rong; Yu, Yong-Xin; Dong, Guan-Mu

    2013-06-01

    To sequence and analyze the full-length gene sequence of rabies vaccine virus aG strain. The full-length gene sequence of aG strain was amplified by RT-PCR by 8 fragments,each PCR product was cloned into vector pGEM-T respectively, sequenced and assemblied; The 5' leader sequence was sequenced with method of 5' RACE. The homology between aG and other rabies vaccine virus was analyzed by using DNAstar and Mega4. 0 software. aG strain was 11 925nt(GenBank accession number: JN234411) in length and belonged to the genotype I . The Bioinformatics revealed that the homology showed disparation form different rabies vaccine virus. the full-length gene sequence of rabies vaccine virus aG strain provided a support for perfecting the standard for quality control of virus strains for production of rabies vaccine for human use in China. PMID:23895005

  16. Laser Cooled High-Power Fiber Amplifier

    OpenAIRE

    Nemova, Galina

    2009-01-01

    A theoretical model for laser cooled continuous-wave fiber amplifier is presented. The amplification process takes place in the Tm3+-doped core of the fluoride ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) glass fiber. The cooling process takes place in the Yb3+:ZBLAN fiber cladding. It is shown that for each value of the pump power and the amplified signal there is a distribution of the concentration of the Tm3+ along the length of the fiber amplifier, which provides its athermal operation. The influence ...

  17. SPS RF System Amplifier plant

    CERN Multimedia

    1977-01-01

    The picture shows a 2 MW, 200 MHz amplifier plant with feeder lines. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X.

  18. High voltage distributed amplifier

    Science.gov (United States)

    Willems, D.; Bahl, I.; Wirsing, K.

    1991-12-01

    A high-voltage distributed amplifier implemented in GaAs MMIC technology has demonstrated good circuit performance over at least two octave bandwidth. This technique allows for very broadband amplifier operation with good efficiency in satellite, active-aperture radar, and battery-powered systems. Also, by increasing the number of FETs, the amplifier can be designed to match different voltage rails. The circuit does require a small amount of additional chip size over conventional distributed amplifiers but does not require power dividers or additional matching networks. This circuit configuration should find great use in broadband power amplifier design.

  19. Genotypic Characterization of Bradyrhizobium Strains Nodulating Endemic Woody Legumes of the Canary Islands by PCR-Restriction Fragment Length Polymorphism Analysis of Genes Encoding 16S rRNA (16S rDNA) and 16S-23S rDNA Intergenic Spacers, Repetitive Extragenic Palindromic PCR Genomic Fingerprinting, and Partial 16S rDNA Sequencing

    OpenAIRE

    Vinuesa, Pablo; Rademaker, Jan L. W.; de Bruijn, Frans J.; Werner, Dietrich

    1998-01-01

    We present a phylogenetic analysis of nine strains of symbiotic nitrogen-fixing bacteria isolated from nodules of tagasaste (Chamaecytisus proliferus) and other endemic woody legumes of the Canary Islands, Spain. These and several reference strains were characterized genotypically at different levels of taxonomic resolution by computer-assisted analysis of 16S ribosomal DNA (rDNA) PCR-restriction fragment length polymorphisms (PCR-RFLPs), 16S-23S rDNA intergenic spacer (IGS) RFLPs, and repeti...

  20. Sequence-Related Amplified Polymorphism (SRAP Markers: A Potential Resource for Studies in Plant Molecular Biology

    Directory of Open Access Journals (Sweden)

    Daniel W. H. Robarts

    2014-07-01

    Full Text Available In the past few decades, many investigations in the field of plant biology have employed selectively neutral, multilocus, dominant markers such as inter-simple sequence repeat (ISSR, random-amplified polymorphic DNA (RAPD, and amplified fragment length polymorphism (AFLP to address hypotheses at lower taxonomic levels. More recently, sequence-related amplified polymorphism (SRAP markers have been developed, which are used to amplify coding regions of DNA with primers targeting open reading frames. These markers have proven to be robust and highly variable, on par with AFLP, and are attained through a significantly less technically demanding process. SRAP markers have been used primarily for agronomic and horticultural purposes, developing quantitative trait loci in advanced hybrids and assessing genetic diversity of large germplasm collections. Here, we suggest that SRAP markers should be employed for research addressing hypotheses in plant systematics, biogeography, conservation, ecology, and beyond. We provide an overview of the SRAP literature to date, review descriptive statistics of SRAP markers in a subset of 171 publications, and present relevant case studies to demonstrate the applicability of SRAP markers to the diverse field of plant biology. Results of these selected works indicate that SRAP markers have the potential to enhance the current suite of molecular tools in a diversity of fields by providing an easy-to-use. highly variable marker with inherent biological significance.

  1. Jet fragmentation

    International Nuclear Information System (INIS)

    Data on jet fragmentation, in particular recent results from e+e- and anti pp collisions, are presented in the framework of phenomenological models. The Lund string model and the Webber QCD cluster model turn out to describe the data quite well. Shortcomings of both models are discussed. (orig.)

  2. Flame Length

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Flame length was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The tool...

  3. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and amplification refractory mutation system (ARMS) analyses of medicinally used Rheum species and their application for identification of Rhei Rhizoma.

    Science.gov (United States)

    Yang, Dong-Ye; Fushimi, Hirotoshi; Cai, Shao-Qing; Komatsu, Katsuko

    2004-05-01

    Previously, we have determined marker nucleotides on the chloroplast matK gene to identify Rheum palmatum, R. tanguticum and R. officinale used as Rhei Rhizoma officially. In the present study, we further developed a convenient and efficient identification method on the basis of marker nucleotides with Amplification Refractory Mutation System analysis. On the basis of the nucleotide substitutions at positions 367 and 937 among the three species on the matK gene, at each position two kinds of reverse primers with complementary 3'-terminal nucleotides were designed. Upon PCR amplification using three sets of primers and template DNA from each species, one or two fragments (202 bp or/and 770 bp) were detected. As the resultant three fragment profiles were species-specific, the procedure enabled us to classify the botanic origins of 22 drug samples of Rhei Rhizoma. PMID:15133241

  4. RF Power Amplifier Analysis

    OpenAIRE

    M. Lokay; K. Pelikan

    1993-01-01

    The special program is presented for the demonstration of RF power transistor amplifiers for the purposes of the high-school education in courses of radio transmitters. The program is written in Turbo Pascal 6. 0 and enables to study the waveforms in selected points of the amplifier and to draw the trajectories of the working point in a plot of output transistor characteristics.

  5. Amplifier improvement circuit

    Science.gov (United States)

    Sturman, J.

    1968-01-01

    Stable input stage was designed for the use with a integrated circuit operational amplifier to provide improved performance as an instrumentation-type amplifier. The circuit provides high input impedance, stable gain, good common mode rejection, very low drift, and low output impedance.

  6. Design of vortex fluid amplifiers with asymmetrical flow fields.

    Science.gov (United States)

    Lawley, T. J.; Price, D. C.

    1972-01-01

    Variation of geometric parameters, including supply area, control area, chamber length, and outlet diameter, of a large scale, modular design vortex fluid amplifier with single supply and control jets, has confirmed and extended a previously published design method, developed for vortex amplifiers with symmetric flow fields. This allows application of the method to devices which are more representative of practical, production type components.

  7. Productivity and biochemical properties of green tea in response to full-length and functional fragments of HpaGXooc, a harpin protein from the bacterial rice leaf streak pathogen Xanthomonas oryzae pv. oryzicola

    Indian Academy of Sciences (India)

    Xiaojing Wu; Tingquan Wu; Juying Long; Qian Yin; Yong Zhang; Lei Chen; Ruoxue Liu; Tongchun Gao; Hansong Dong

    2007-09-01

    Harpin proteins from plant pathogenic bacteria can stimulate hypersensitive cell death (HCD), drought tolerance, defence responses against pathogens and insects in plants, as well as enhance plant growth. Recently, we identified nine functional fragments of HpaGXooc, a harpin protein from Xanthomonas oryzae pv. oryzicola, the pathogen that causes bacterial leaf streak in rice. Fragments HpaG1–94, HpaG10–42, and HpaG62–138, which contain the HpaGXooc regions of the amino acid sequence as indicated by the number spans, exceed the parent protein in promoting growth, pathogen defence and HCD in plants. Here we report improved productivity and biochemical properties of green tea (Camellia sinensis) in response to the fragments tested in comparison with HpaGXooc and an inactive protein control. Field tests suggested that the four proteins markedly increased the growth and yield of green tea, and increased the leaf content of tea catechols, a group of compounds that have relevance in the prevention and treatment of human diseases. In particular, HpaG1–94 was more active than HpaGXooc in expediting the growth of juvenile buds and leaves used as green tea material and increased the catechol content of processed teas. When tea shrubs were treated with HpaHXooc and HpaG1–94 compared with a control, green tea yields were over 55% and 39% greater, and leaf catechols were increased by more than 64% and 72%, respectively. The expression of three homologues of the expansin genes, which regulate plant cell growth, and the CsCHS gene encoding a tea chalcone synthase, which critically regulates the biosynthesis of catechols, were induced in germinal leaves of tea plants following treatment with HpaG1–94 or HpaGXooc. Higher levels of gene expression were induced by the application of HpaG1–94 than HpaGXooc. Our results suggest that the harpin protein, especially the functional fragment HpaG1–94, can be used to effectively increase the yield and improve the biochemical

  8. Semiconductor optical amplifiers

    CERN Document Server

    Dutta, Niloy K

    2013-01-01

    This invaluable look provides a comprehensive treatment of design and applications of semiconductor optical amplifiers (SOA). SOA is an important component for optical communication systems. It has applications as in-line amplifiers and as functional devices in evolving optical networks. The functional applications of SOAs were first studied in the early 1990's, since then the diversity and scope of such applications have been steadily growing. This is the second edition of a book on Semiconductor Optical Amplifiers first published in 2006 by the same authors. Several chapters and sections rep

  9. CLONING AND SEQUENCING OF MATURED FRAGMENT OF HUMAN NEVER GROWTH FACTOR GENE

    Institute of Scientific and Technical Information of China (English)

    马巍; 吴玲; 王德利; 刘淼; 任惠民; 杨广笑; 王全颖

    2003-01-01

    Objective Molecular cloning and sequencing of the human matured fragment of human nerve growth factor(NGF) gene. Methods Extracting the human genomic DNA from the white blood cells as templates, the gene of NGF was cloned by using PCR and T-vector cloning method. Screening the positive clones and identified by the restriction enzymes, and then the cloned amplified fragment was sequenced and analyzed. Results DNA sequence comparison the cloned gene of NGF with the GenBank (V01511) sequence demonstrated that both of sequences were identical, 354bp length. Conclusion Cloning the NGF gene from the human genomic DNA has paved the way for further study on gene therapy of nerve system injury.

  10. Diversity of the marine picocyanobacteria Prochlorococcus and Synechococcus assessed by terminal restriction fragment length polymorphisms of 16S-23S rRNA internal transcribed spacer sequences Diversidad de las picocianobacterias marinas Prochlorococcus y Synechococcus por medio de polimorfismos de longitud de fragmentos de restricción terminal en secuencias del espaciador transcrito interno del ARNr 16S - 23S

    Directory of Open Access Journals (Sweden)

    PARIS LAVIN

    2008-12-01

    Full Text Available In order to assess the appropriateness of the use of internal transcribed spacer (ITS sequences for the study of population genetics of marine cyanobacteria, we amplified and cloned the 16S rRNA gene plus the 16S-23S ITS regions of six strains of Prochlorococcus and Synechococcus. We analyzed them by denaturing gradient gel electrophoresis (DGGE and terminal restriction fragment length polymorphisms (T-RFLP. When using the standard application of these techniques, we obtained more than one band or terminal restriction fragment (T-RF per strain or cloned sequence. Reports in literature have suggested that these anomalies can result from the formation of secondary structures. Secondary structures of the ITS sequences of Prochlorococcus and Synechococcus strains were computationally modelled at the different temperatures that were used during the polymerase chain reaction (PCR. Modelling results predicted the existence of hairpin loops that would still be present at the extensión temperature; it is likely that these loops produced incomplete and single stranded PCR products. We modified the standard T-RFLP procedure by adding the labelled ITS primer in the last two cycles of the PCR reaction; this resulted, in most cases, in only one T-RF per ribotype. Application of this technique to a natural picoplankton community in marine waters off northern Chile, showed that it was possible to identify the presence, and determine the relative abundance, of several phylogenetic lineages within the genera Prochlorococcus and Synechococcus inhabiting the euphotic zone. Phylogenetic analysis of ITS sequences obtained by cloning and sequencing DNA from the same sample confirmed the presence of the different genotypes. With the proposed modification, T-RFLP profiles should therefore be suitable for studying the diversity of natural populations of cyanobacteria, and should become an important tool to study the factors influencing the genetic structure and

  11. Sex determination in highly fragmented human DNA by high-resolution melting (HRM) analysis.

    Science.gov (United States)

    Álvarez-Sandoval, Brenda A; Manzanilla, Linda R; Montiel, Rafael

    2014-01-01

    Sex identification in ancient human remains is a common problem especially if the skeletons are sub-adult, incomplete or damaged. In this paper we propose a new method to identify sex, based on real-time PCR amplification of small fragments (61 and 64 bp) of the third exon within the amelogenin gene covering a 3-bp deletion on the AMELX-allele, followed by a High Resolution Melting analysis (HRM). HRM is based on the melting curves of amplified fragments. The amelogenin gene is located on both chromosomes X and Y, showing dimorphism in length. This molecular tool is rapid, sensitive and reduces the risk of contamination from exogenous genetic material when used for ancient DNA studies. The accuracy of the new method described here has been corroborated by using control samples of known sex and by contrasting our results with those obtained with other methods. Our method has proven to be useful even in heavily degraded samples, where other previously published methods failed. Stochastic problems such as the random allele drop-out phenomenon are expected to occur in a less severe form, due to the smaller fragment size to be amplified. Thus, their negative effect could be easier to overcome by a proper experimental design. PMID:25098828

  12. Sex determination in highly fragmented human DNA by high-resolution melting (HRM analysis.

    Directory of Open Access Journals (Sweden)

    Brenda A Álvarez-Sandoval

    Full Text Available Sex identification in ancient human remains is a common problem especially if the skeletons are sub-adult, incomplete or damaged. In this paper we propose a new method to identify sex, based on real-time PCR amplification of small fragments (61 and 64 bp of the third exon within the amelogenin gene covering a 3-bp deletion on the AMELX-allele, followed by a High Resolution Melting analysis (HRM. HRM is based on the melting curves of amplified fragments. The amelogenin gene is located on both chromosomes X and Y, showing dimorphism in length. This molecular tool is rapid, sensitive and reduces the risk of contamination from exogenous genetic material when used for ancient DNA studies. The accuracy of the new method described here has been corroborated by using control samples of known sex and by contrasting our results with those obtained with other methods. Our method has proven to be useful even in heavily degraded samples, where other previously published methods failed. Stochastic problems such as the random allele drop-out phenomenon are expected to occur in a less severe form, due to the smaller fragment size to be amplified. Thus, their negative effect could be easier to overcome by a proper experimental design.

  13. RF Power Amplifier Analysis

    Directory of Open Access Journals (Sweden)

    M. Lokay

    1993-04-01

    Full Text Available The special program is presented for the demonstration of RF power transistor amplifiers for the purposes of the high-school education in courses of radio transmitters. The program is written in Turbo Pascal 6. 0 and enables to study the waveforms in selected points of the amplifier and to draw the trajectories of the working point in a plot of output transistor characteristics.

  14. Noise in Optical Amplifiers

    DEFF Research Database (Denmark)

    Jeppesen, Palle

    1997-01-01

    Noise in optical amplifiers is discussed on the basis of photons and electromagntic fields. Formulas for quantum noise from spontaneous emission, signal-spontaneous beat noise and spontaneous-spontaneous beat noise are derived.......Noise in optical amplifiers is discussed on the basis of photons and electromagntic fields. Formulas for quantum noise from spontaneous emission, signal-spontaneous beat noise and spontaneous-spontaneous beat noise are derived....

  15. Charge-sensitive amplifier

    OpenAIRE

    Startsev V. I.; Yampolsky Ju. S.

    2008-01-01

    The authors consider design and circuit design techniques of reduction of the influence of the pyroelectric effect on operation of the charge sensitive amplifiers. The presented experimental results confirm the validity of the measures taken to reduce the impact of pyroelectric currents. Pyroelectric currents are caused by the influence of the temperature gradient on the piezoelectric sensor and on the output voltage of charge sensitive amplifiers.

  16. E-537 MWPC amplifier

    International Nuclear Information System (INIS)

    The design of a fast MWPC amplifier for the beam chambers and the absorber chamber is completed and all parts are on order. A prototype 16 channel board has been built and satisfactorily tested. Artwork is completed for the board and out to be photographed. The board fabrication contract has been let. Listed below is a summary of the amplifier characteristics as well as test results obtained with the prototype

  17. Electrospun Amplified Fiber Optics

    OpenAIRE

    Morello, Giovanni; Camposeo, Andrea; Moffa, Maria; Pisignano, Dario

    2015-01-01

    A lot of research is focused on all-optical signal processing, aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for an efficient signal transmission. However, the complex fabrication methods, involving high-temperature processes performed in highly pure environment, slow down the fabrication and make amplified components expensive with respect to an ideal, ...

  18. Framing Fragmentation

    DEFF Research Database (Denmark)

    Bundgaard, Charlotte

    2009-01-01

    , contain distinctive architectural traits, not only based on rational repetition, but also supporting composition and montage as dynamic concepts. Prefab architecture is an architecture of fragmentation, individualization and changeability, and this sets up new challenges for the architect. This paper...... tries to develop a strategy for the architect dealing with industrially based architecture; a strategy which exploits architectural potentials in industrial building, which recognizes the rules of mass production and which redefines the architect’s position among the agents of building. If recent...... developments within the construction sector imply a marginalized role for the architect, this strategy suggests a strong repositioning. In Danish building practice the construction industry is increasingly organized within terms like ”systemized prefab delivery” and ”digital building”. The building is divided...

  19. Seqüenciamento e variabilidade do fragmento genômico de Xylella fastidiosa amplificado pelos iniciadores RST31/33 Sequencing and variability of the Xylella fastidosa - specific genomic fragment amplified by the primer pair RST 31/33

    Directory of Open Access Journals (Sweden)

    Adriane Wendland

    2003-06-01

    Full Text Available Xylella fastidiosa é agente causal de diversas doenças de importância econômica como a clorose variegada dos citros (Citrus spp. (CVC, mal de Pierce da videira (Vitis vinifera, escaldadura da ameixeira (Prunus salicina e requeima do cafeeiro (Coffea arabica. A seqüência nucleotídica do fragmento genômico, específico de X. fastidiosa, amplificado pelo par de iniciadores RST31/33 foi determinada para 38 isolados de citros e para isolados de videira, cafeeiro e ameixeira objetivando avaliar o nível de polimorfismo entre isolados e a identidade genômica do fragmento. Não foi observado polimorfismo de seqüência nucleotídica entre isolados de citros, mas foi detectado polimorfismo entre isolados de citros e de videira, cafeeiro e ameixeira. A presença do sítio de clivagem RsaI, que distingue isolados de citros e videira de isolados de ameixeira e outras espécies arbóreas, foi identificada em um isolado de ameixeira proveniente dos EUA mas não em outro proveniente do Brasil.Xylella fastidiosa causes several plant diseases of economic importance such as citrus (Citrus spp. variegated chlorosis (CVC, Pierce's disease of grapevine (Vitis vinifera and leaf scorch of plum (Prunus salicina and coffee (Coffea arabica. The nucleotide sequence of the genomic fragment, specific to Xylella fastidosa, amplified by the pair of primers RST 31/33, was determined for 38 isolates from citrus and for isolates from grapevine, coffee and plum in order to assess the level of sequence polymorphism of this fragment among isolates, as well as its genomic identity. Sequence polymorphism was not observed among isolates from citrus, but was detected among isolates from citrus and from grapevine, coffee and plum. The presence of a RsaI restriction site, which distinguishes isolates from citrus and grapevine from plum and other arboreal species, was identified in a North American isolate from plum but not in a Brazilian one.

  20. Fragmentation of an axially impacted slender rod

    Science.gov (United States)

    Ji, W.; Waas, A. M.

    2010-02-01

    Motivated by experimental results on the dynamic buckling and fragmentation of a vertical column impacted by a falling mass, results from an analytical model for dynamic buckling which considers the dynamic interaction between the axial column deformation and the out-of-plane buckling displacements are used to interpret the fragmentation process and the resulting fragment lengths. It is shown that a critical time exists for the rod to undergo fragmentation. At this critical time, the rod deforms in a modulated pattern of waves, setting up the stage for the ensuing fragmentation as a result of induced large curvatures that exceed the critical bending strain of the rod material. The resulting fragment length distributions, which show two characteristics peaks at \\frac{\\lambda}{2} and \\frac{\\lambda}{4} , where λ is a characteristic half-wavelength, are found to compare favorably with the experimental results.

  1. Chemical Production using Fission Fragments

    International Nuclear Information System (INIS)

    Some reactor design considerations of the use of fission recoil fragment energy for the production of chemicals of industrial importance have been discussed previously in a paper given at the Second United Nations International Conference on the Peaceful Uses of Atomic Energy [A/Conf. 15/P.76]. The present paper summarizes more recent progress made on this topic at AERE, Harwell. The range-energy relationship for fission fragments is discussed in the context of the choice of fuel system for a chemical production reactor, and the experimental observation of a variation of chemical effect along the length of a fission fragment track is described for the irradiation of nitrogen-oxygen mixtures. Recent results are given on the effect of fission fragments on carbon monoxide-hydrogen gas mixtures and on water vapour. No system investigated to date shows any outstanding promise for large-scale chemical production. (author)

  2. Telomere Restriction Fragment (TRF) Analysis

    Science.gov (United States)

    Mender, Ilgen; Shay, Jerry W.

    2016-01-01

    While telomerase is expressed in ~90% of primary human tumors, most somatic tissue cells except transiently proliferating stem-like cells do not have detectable telomerase activity (Shay and Wright, 1996; Shay and Wright, 2001). Telomeres progressively shorten with each cell division in normal cells, including proliferating stem-like cells, due to the end replication (lagging strand synthesis) problem and other causes such as oxidative damage, therefore all somatic cells have limited cell proliferation capacity (Hayflick limit) (Hayflick and Moorhead, 1961; Olovnikov, 1973). The progressive telomere shortening eventually leads to growth arrest in normal cells, which is known as replicative senescence (Shay et al., 1991). Once telomerase is activated in cancer cells, telomere length is stabilized by the addition of TTAGGG repeats to the end of chromosomes, thus enabling the limitless continuation of cell division (Shay and Wright, 1996; Shay and Wright, 2001). Therefore, the link between aging and cancer can be partially explained by telomere biology. There are many rapid and convenient methods to study telomere biology such as Telomere Restriction Fragment (TRF), Telomere Repeat Amplification Protocol (TRAP) (Mender and Shay, 2015b) and Telomere dysfunction Induced Foci (TIF) analysis (Mender and Shay, 2015a). In this protocol paper we describe Telomere Restriction Fragment (TRF) analysis to determine average telomeric length of cells. Telomeric length can be indirectly measured by a technique called Telomere Restriction Fragment analysis (TRF). This technique is a modified Southern blot, which measures the heterogeneous range of telomere lengths in a cell population using the length distribution of the terminal restriction fragments (Harley et al., 1990; Ouellette et al., 2000). This method can be used in eukaryotic cells. The description below focuses on the measurement of human cancer cells telomere length. The principle of this method relies on the lack of

  3. 不同年龄组白细胞端粒DNA长度变化研究%Study on the dynamic changing profiles of telomeric restricted fragment length among sex balanced different age groups

    Institute of Scientific and Technical Information of China (English)

    葛璐璐; 刘超; 陶黎阳; 陈晓晖; 赵永忠

    2003-01-01

    目的探讨人外周血白细胞端粒DNA随年龄变化的规律.方法选取123例不同年龄健康人外周血样本,采用非同位素探针标记的Southern Blot方法检测了端粒DNA限制性酶切片段(Telomeric re-stricted fragment,TRF)长度的变化.结果对这123例样本就性别组成进行X2检验,得出P>0.05,说明这123例样品性别对TRF的差异不显著.123例外周血白细胞端粒TRF平均长度随年龄增长而逐渐缩短,且TRF随年龄缩短的速度是不均一的,人外周血白细胞染色体端粒DNA长度可能在5岁左右存在缩短加剧现象.对0~14岁、15~64岁及≥65岁三组进行方差分析(SNK检验),显示有显著性差异(P<0.01).结论不同年龄组人外周血白细胞端粒DNA长度具有显著差异且变化速率不同,该研究结果为通过端粒DNA长度推断个体年龄提供了可能.

  4. A micropower electrocardiogram amplifier.

    Science.gov (United States)

    Fay, L; Misra, V; Sarpeshkar, R

    2009-10-01

    We introduce an electrocardiogram (EKG) preamplifier with a power consumption of 2.8 muW, 8.1 muVrms input-referred noise, and a common-mode rejection ratio of 90 dB. Compared to previously reported work, this amplifier represents a significant reduction in power with little compromise in signal quality. The improvement in performance may be attributed to many optimizations throughout the design including the use of subthreshold transistor operation to improve noise efficiency, gain-setting capacitors versus resistors, half-rail operation wherever possible, optimal power allocations among amplifier blocks, and the sizing of devices to improve matching and reduce noise. We envision that the micropower amplifier can be used as part of a wireless EKG monitoring system powered by rectified radio-frequency energy or other forms of energy harvesting like body vibration and body heat. PMID:23853270

  5. A vircator amplifier

    International Nuclear Information System (INIS)

    A cavity vircator has demonstrated that formation of a virtual cathode in a cavity can improve microwave production efficiency and narrow the radiation bandwidth. When the virtual cathode radiates the microwave fields grow from noise. For each cavity, there is only one or a limited number of allowable modes for a given frequency. In this paper, a novel device - a vircator amplifier is described. The device consists of a relativistic magnetron and a cavity vircator with both devices powered by a 1 MeV, 3 Ω, 65 ns FWHM pulser. The idea is to inject a signal from the magnetron before and during virtual cathode formation in a cavity. The injected signal should lock the frequency and enhance electron bunching and therefore improve efficiency further. Experiments underway to evaluate the amplifier operating characteristics are discussed. The applicability of vircator amplifiers to the next generation of high-power microwave devices are addressed

  6. [Construction and sequencing of full-length cDNA of peste des petits ruminants virus].

    Science.gov (United States)

    Zhai, Jun-Jun; Dou, Yong-Xi; Zhang, Hai-Rui; Mao, Li; Meng, Xue-Lian; Luo, Xuo-Nong; Cai, Xue-Peng

    2010-07-01

    To develop a reverse genetics system of Peste des petits ruminants virus(PPRV), five pairs of oligonucleotide primers were designed on the basis of the full-length genomic sequence of PPRV Nigeria 75/ 1 strain. Using RT-PCR technique, five over-lapping cDNA fragments, designated as JF1, JF2, JF3, JF4 and JF5, respectively, were amplified, followed by cloning into pcDNA3.1(+)vector. An AscI restriction enzyme site and a T7 promoter sequence were introduced immediately upstream of 5'-end, while a PacI restriction enzyme site was engineered downstream of 3'-end. Using pok12 as a plasmid vector, the full-length cDNA clone pok12-PPRV of Nigeria 75/1 was assembled by connecting the five cDNA fragments via the unique restriction endonuclease site of PPRV genome. The resultant nucleotide sequence of the PPRV Nigeria 75/1 strain in the study was compared with other members of genus morbillivirus, and phylogenetic analysis was used to examine the evolutionary relationships. The results showed that PPRV Nigeria 75/ 1 was antigenically closely related to Rinderpest virus and Measles virus. Successful construction of full-length cDNA clone of PPRV Nigeria 75/1 strain lays the basis rescuing PPRV effectively and enables further research of PPRV at molecular level. PMID:20836386

  7. Development of a restriction length polymorphism combined with direct PCR technique to differentiate goose and Muscovy duck parvoviruses

    Science.gov (United States)

    WAN, Chun-He; CHEN, Hong-Mei; FU, Qiu-Ling; SHI, Shao-Hua; FU, Guang-Hua; CHENG, Long-Fei; CHEN, Cui-Teng; HUANG, Yu; HU, Kai-Hui

    2016-01-01

    A restriction fragment length polymorphism combined with direct PCR technique to differentiate goose and Muscovy duck parvoviruses (GPV and MDPV) was developed based on comparison of the NS gene of GPV and MDPV. Both GPV and MDPV genomic DNA can be amplified with 641 bp using the specific PCR primers. The PCR fragments can be cut into 463 bp and 178 bp only in the case of MDPV-derived PCR products, whereas the GPV-derived PCR products cannot. The method established in this study can be used to differentiate GPV and MDPV with high specificity and precision, by using a direct PCR kit and QuickCut enzyme, as quickly as conventional PCR. PMID:26854108

  8. STABILIZED TRANSISTOR AMPLIFIER

    Science.gov (United States)

    Noe, J.B.

    1963-05-01

    A temperature stabilized transistor amplifier having a pair of transistors coupled in cascade relation that are capable of providing amplification through a temperature range of - 100 un. Concent 85% F to 400 un. Concent 85% F described. The stabilization of the amplifier is attained by coupling a feedback signal taken from the emitter of second transistor at a junction between two serially arranged biasing resistances in the circuit of the emitter of the second transistor to the base of the first transistor. Thus, a change in the emitter current of the second transistor is automatically corrected by the feedback adjustment of the base-emitter potential of the first transistor and by a corresponding change in the base-emitter potential of the second transistor. (AEC)

  9. Principal modes in fiber amplifiers

    CERN Document Server

    Fridman, Moti; Dubinskii, Mark; Friesem, Asher A; Davidson, Nir

    2010-01-01

    The dynamics of the state of polarization in single mode and multimode fiber amplifiers are presented. The experimental results reveal that although the state of polarizations at the output can vary over a large range when changing the temperatures of the fiber amplifiers, the variations are significantly reduced when resorting to the principal states of polarization in single mode fiber amplifiers and principal modes in multimode fiber amplifiers.

  10. Helical Fiber Amplifier

    Science.gov (United States)

    Koplow, Jeffrey P.; Kliner, Dahy; Goldberg, Lew

    2002-12-17

    A multi-mode gain fiber is provided which affords substantial improvements in the maximum pulse energy, peak power handling capabilities, average output power, and/or pumping efficiency of fiber amplifier and laser sources while maintaining good beam quality (comparable to that of a conventional single-mode fiber source). These benefits are realized by coiling the multimode gain fiber to induce significant bend loss for all but the lowest-order mode(s).

  11. Radio Frequency Solid State Amplifiers

    CERN Document Server

    Jacob, J

    2015-01-01

    Solid state amplifiers are being increasingly used instead of electronic vacuum tubes to feed accelerating cavities with radio frequency power in the 100 kW range. Power is obtained from the combination of hundreds of transistor amplifier modules. This paper summarizes a one hour lecture on solid state amplifiers for accelerator applications.

  12. [Rescue of bovine Asia 1 serotype foot-and-mouth disease virus from a full-length cDNA clone].

    Science.gov (United States)

    Li, Shuang; Zhang, Runxiang; Song, Ge; Gao, Mingchun; Liu, Xiangtao; Wang, Junwei

    2009-11-01

    After sequencing the Asia 1 foot-and-mouth disease virus (FMDV) (As01 strain), we amplified the two fragments covering the whole genome by overlapping PCR and long PCR. The 5' fragment was 1.8 kb in length including 15Cs, and the 3' fragment was 6.7 kb in length. The two fragments were cloned into the pBluescript SK vector to construct recombinant plasmid pBSAs carrying the full-length cDNA of FMDV As01 strain. The RNA transcript was synthesized in vitro using T7 polymerase and transfected into BHK-21 cells. We observed the typical CPE caused by rescued FMDV. The harvested virus was confirmed to be Asia 1 FMDV by RT-PCR, indirect immunofluorescence assay (IFA) and electron microscope observation. The rescued virus showed a similar pathogenicity in suckling mouse (LD50) compared to its wild-type virus. The infectious cDNA clone of the FMDV As01 strain laid a new ground for further investigation of FMDV virulence determinants and development of novel vaccines against FMD. PMID:20222458

  13. Electronic amplifiers for automatic compensators

    CERN Document Server

    Polonnikov, D Ye

    1965-01-01

    Electronic Amplifiers for Automatic Compensators presents the design and operation of electronic amplifiers for use in automatic control and measuring systems. This book is composed of eight chapters that consider the problems of constructing input and output circuits of amplifiers, suppression of interference and ensuring high sensitivity.This work begins with a survey of the operating principles of electronic amplifiers in automatic compensator systems. The succeeding chapters deal with circuit selection and the calculation and determination of the principal characteristics of amplifiers, as

  14. Simplified design of IC amplifiers

    CERN Document Server

    Lenk, John

    1996-01-01

    Simplified Design of IC Amplifiers has something for everyone involved in electronics. No matter what skill level, this book shows how to design and experiment with IC amplifiers. For experimenters, students, and serious hobbyists, this book provides sufficient information to design and build IC amplifier circuits from 'scratch'. For working engineers who design amplifier circuits or select IC amplifiers, the book provides a variety of circuit configurations to make designing easier.Provides basics for all phases of practical design.Covers the most popular forms for amplif

  15. CARM and harmonic gyro-amplifier experiments at 17 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Menninger, W.L.; Danly, B.G.; Alberti, S.; Chen, C.; Rullier, J.L.; Temkin, R.J. [Massachusetts Inst. of Technology, Cambridge, MA (United States). Plasma Fusion Center; Giguet, E. [Massachusetts Inst. of Technology, Cambridge, MA (United States). Plasma Fusion Center]|[Thomson Tubes Electroniques, Velizy (France)

    1993-11-01

    Cyclotron resonance maser amplifiers are possible sources for applications such as electron cyclotron resonance heating of fusion plasmas and driving high-gradient rf linear accelerators. For accelerator drivers, amplifiers or phase locked-oscillators are required. A 17 GHz cyclotron autoresonance maser (CARM) amplifier experiment and a 17 GHz third harmonic gyro-amplifier experiment are presently underway at the MIT Plasma Fusion Center. Using the SRL/MIT SNOMAD II introduction accelerator to provide a 380 kV, 180 A, 30 ns flat top electron beam, the gyro-amplifier experiment has produced 5 MW of rf power with over 50 dB of gain at 17 GHz. The gyro-amplifier operates in the TE{sub 31} mode using a third harmonic interaction. Because of its high power output, the gyro-amplifier will be used as the rf source for a photocathode rf electron gun experiment also taking place at MIT. Preliminary gyro-amplifier results are presented, including measurement of rf power, gain versus interaction length, and the far-field pattern. A CARM experiment designed to operate in the TE{sub 11} mode is also discussed.

  16. CARM and harmonic gyro-amplifier experiments at 17 GHz

    International Nuclear Information System (INIS)

    Cyclotron resonance maser amplifiers are possible sources for applications such as electron cyclotron resonance heating of fusion plasmas and driving high-gradient rf linear accelerators. For accelerator drivers, amplifiers or phase locked-oscillators are required. A 17 GHz cyclotron autoresonance maser (CARM) amplifier experiment and a 17 GHz third harmonic gyro-amplifier experiment are presently underway at the MIT Plasma Fusion Center. Using the SRL/MIT SNOMAD II introduction accelerator to provide a 380 kV, 180 A, 30 ns flat top electron beam, the gyro-amplifier experiment has produced 5 MW of rf power with over 50 dB of gain at 17 GHz. The gyro-amplifier operates in the TE31 mode using a third harmonic interaction. Because of its high power output, the gyro-amplifier will be used as the rf source for a photocathode rf electron gun experiment also taking place at MIT. Preliminary gyro-amplifier results are presented, including measurement of rf power, gain versus interaction length, and the far-field pattern. A CARM experiment designed to operate in the TE11 mode is also discussed

  17. Building valve amplifiers

    CERN Document Server

    Jones, Morgan

    2013-01-01

    Building Valve Amplifiers is a unique hands-on guide for anyone working with tube audio equipment--as an electronics hobbyist, audiophile or audio engineer. This 2nd Edition builds on the success of the first with technology and technique revisions throughout and, significantly, a major new self-build project, worked through step-by-step, which puts into practice the principles and techniques introduced throughout the book. Particular attention has been paid to answering questions commonly asked by newcomers to the world of the valve, whether audio enthusiasts tackling their first build or

  18. Wideband amplifier design

    CERN Document Server

    Hollister, Allen L

    2007-01-01

    In this book, the theory needed to understand wideband amplifier design using the simplest models possible will be developed. This theory will be used to develop algebraic equations that describe particular circuits used in high frequency design so that the reader develops a ""gut level"" understanding of the process and circuit. SPICE and Genesys simulations will be performed to show the accuracy of the algebraic models. By looking at differences between the algebraic equations and the simulations, new algebraic models will be developed that include parameters originally left out of the model

  19. REGENERATIVE TRANSISTOR AMPLIFIER

    Science.gov (United States)

    Kabell, L.J.

    1958-11-25

    Electrical circults for use in computers and the like are described. particularly a regenerative bistable transistor amplifler which is iurned on by a clock signal when an information signal permits and is turned off by the clock signal. The amplifier porforms the above function with reduced power requirements for the clock signal and circuit operation. The power requirements are reduced in one way by employing transformer coupling which increases the collector circuit efficiency by eliminating the loss of power in the collector load resistor.

  20. Quantum entanglement degrees amplifier

    CERN Document Server

    Wu, Xiang-Yao; Liu, Xiao-Jing; Liang, Yu; Meng, Xiang-Dong; Li, Hong; Zhang, Si-Qi

    2015-01-01

    The quantum entangled degrees of entangled states become smaller with the transmission distance increasing, how to keep the purity of quantum entangled states is the puzzle in quantum communication. In the paper, we have designed a new type entanglement degrees amplifier by one-dimensional photonic crystal, which is similar as the relay station of classical electromagnetic communication. We find when the entangled states of two-photon and three-photon pass through photonic crystal, their entanglement degrees can be magnified, which make the entanglement states can be long range propagation and the quantum communication can be really realized.

  1. Restriction Fragment Length Polymorphisms of Virulence Plasmids in Rhodococcus equi

    OpenAIRE

    Takai, Shinji; Shoda, Masato; Sasaki, Yukako; Tsubaki, Shiro; Fortier, Guillaume; Pronost, Stephane; Rahal, Karim; Becu, Teotimo; Begg, Angela; Browning, Glenn; Nicholson, Vivian M.; Prescott, John F.

    1999-01-01

    Virulent Rhodococcus equi, which is a well-known cause of pyogranulomatous pneumonia in foals, possesses a large plasmid encoding virulence-associated 15- to 17-kDa antigens. Foal and soil isolates from five countries—Argentina, Australia, Canada, France, and Japan—were investigated for the presence of 15- to 17-kDa antigens by colony blotting, using the monoclonal antibody 10G5, and the gene coding for 15- to 17-kDa antigens by PCR. Plasmid DNAs extracted from positive isolates were digested...

  2. DIAMOND AMPLIFIED PHOTOCATHODES.

    Energy Technology Data Exchange (ETDEWEB)

    SMEDLEY,J.; BEN-ZVI, I.; BOHON, J.; CHANG, X.; GROVER, R.; ISAKOVIC, A.; RAO, T.; WU, Q.

    2007-11-26

    High-average-current linear electron accelerators require photoinjectors capable of delivering tens to hundreds of mA average current, with peak currents of hundreds of amps. Standard photocathodes face significant challenges in meeting these requirements, and often have short operational lifetimes in an accelerator environment. We report on recent progress toward development of secondary emission amplifiers for photocathodes, which are intended to increase the achievable average current while protecting the cathode from the accelerator. The amplifier is a thin diamond wafer which converts energetic (few keV) primary electrons into hundreds of electron-hole pairs via secondary electron emission. The electrons drift through the diamond under an external bias and are emitted into vacuum via a hydrogen-terminated surface with negative electron affinity (NEA). Secondary emission gain of over 200 has been achieved. Two methods of patterning diamond, laser ablation and reactive-ion etching (RIE), are being developed to produce the required geometry. A variety of diagnostic techniques, including FTIR, SEM and AFM, have been used to characterize the diamonds.

  3. Universal Signal Conditioning Amplifier

    Science.gov (United States)

    Kinney, Frank

    1997-01-01

    The Technological Research and Development Authority (TRDA) and NASA-KSC entered into a cooperative agreement in March of 1994 to achieve the utilization and commercialization of a technology development for benefiting both the Space Program and U.S. industry on a "dual-use basis". The technology involved in this transfer is a new, unique Universal Conditioning Amplifier (USCA) used in connection with various types of transducers. The project was initiated in partnership with I-Net Corporation, Lockheed Martin Telemetry & Instrumentation (formerly Loral Test and Information Systems) and Brevard Community College. The project consists of designing, miniaturizing, manufacturing, and testing an existing prototype of USCA that was developed for NASA-KSC by the I-Net Corporation. The USCA is a rugged and field-installable self (or remotely)- programmable amplifier that works in combination with a tag random access memory (RAM) attached to various types of transducers. This summary report comprises performance evaluations, TRDA partnership tasks, a project summary, project milestones and results.

  4. Fragman: an R package for fragment analysis

    OpenAIRE

    Covarrubias-Pazaran, Giovanny; Diaz-Garcia, Luis; Schlautman, Brandon; Salazar, Walter; Zalapa, Juan

    2016-01-01

    Background Determination of microsatellite lengths or other DNA fragment types is an important initial component of many genetic studies such as mutation detection, linkage and quantitative trait loci (QTL) mapping, genetic diversity, pedigree analysis, and detection of heterozygosity. A handful of commercial and freely available software programs exist for fragment analysis; however, most of them are platform dependent and lack high-throughput applicability. Results We present the R package ...

  5. 华山松疱锈病的重寄生真菌(深绿木霉)中几丁质酶基因cDNA片段的克隆%Cloning of cDNA Fragment of Chitinase Gene from the Mycoparasite Trichoderma atroviride on Armandii Pine Blister Rust

    Institute of Scientific and Technical Information of China (English)

    马长乐; 李靖; 陈玉惠; 刘小烛

    2008-01-01

    [Objective] The aim of this study was to isolate chitinase gene from Trichoderma atroviride strain SS003. [Method] With the aeciospore wall of armandii pine blister rust as inducer, chitinase gene was induced to express in Trichoderma atroviride cells. The cDNA fragment of chitinase gene was cloned by RT-PCR approach. [Result] The activity of chitinase induced reached 40.17 μg/10 min; and the specific fragment amplified was 834 bp in length and proved to be the fragment of chitinase gene by sequencing and sequence analysis. [Conclusion] The result showed the feasibility of isolating the full length of chitinase gene and its transformation, and further producing chitinase.

  6. High sensitivity amplifier/discriminator for PWC's

    International Nuclear Information System (INIS)

    The facility support group at Fermilab is designing and building a general purpose beam chamber for use in several locations at the laboratory. This pwc has 128 wires per plane spaced 1 mm apart. An initial production of 25 signal planes is anticipated. In proportional chambers, the size of the signal depends exponentially on the charge stored per unit of length along the anode wire. As the wire spacing decreases, the capacitance per unit length decreases, thereby requiring increased applied voltage to restore the necessary charge per unit length. In practical terms, this phenomenon is responsible for difficulties in constructing chambers with less than 2 mm wire spacing. 1 mm chambers, therefore, are frequently operated very near to their breakdown point and/or a high gain gas containing organic compounds such as magic gas is used. This argon/iso-butane mixture has three drawbacks: it is explosive when exposed to the air, it leaves a residue on the wires after extended use and is costly. An amplifier with higher sensitivity would reduce the problems associated with operating chambers with small wire spacings and allow them to be run a safe margin below their breakdown voltage even with an inorganic gas mixture such as argon/CO2, this eliminating the need to use magic gas. Described here is a low cost amplifier with a usable threshold of less than 0.5 μA. Data on the performance of this amplifier/discriminator in operation on a prototype beam chamber are given. This data shows the advantages of the high sensitivity of this design

  7. Characterisation Of Low Noise Amplifier

    OpenAIRE

    MAULIK B.PATEL; ABHISEK CHOBEY; SUNIL B.PATEL

    2012-01-01

    Amplification is one of the most basic and prevalent microwave circuit functions inmodern RF and microwave systems. Early microwave amplifiers relied on tubes, such asklystrons and traveling-wave tubes, or solid-state reflection amplifiers based on thenegative resistance characteristics of tunnel or varactor diodes. But due to the dramaticimprovements and innovations in solid-state technology that have occurred since the1970s, most RF and microwave amplifiers today use transistor devices such...

  8. Modeling of semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Mørk, Jesper; Bischoff, Svend; Berg, Tommy Winther;

    We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed.......We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed....

  9. Amplified leak detection

    Energy Technology Data Exchange (ETDEWEB)

    Mahony, James

    2011-12-15

    Leaks are one of the major concerns for oil and gas producers. But recently, a Calgary-based company developed a tool that can find natural gas leaks in wellbores. This has relieved the oil and gas producers because the optics of finding downhole leaks just got a little brighter. Since then, there have been continuous efforts to broaden and refine fiber optics based methods. This paper presents amplified leak detection using fiber optics to identify even the smallest liquid leaks downhole. At high volumes, detection of downhole leaks in liquids is not a problem but at lower flow rates, the leaks become harder to detect, and at very low flow rates, they might not be detected at all. Hifi Engineering Inc. has developed the LeakSonar fiber optic acoustic sensor array that is specifically designed to detect and locate fluid migration in wellbores, even through multiple strings of casing.

  10. Metatronic transistor amplifier

    Science.gov (United States)

    Chettiar, Uday K.; Engheta, Nader

    2015-10-01

    Utilizing the notion of metamaterials, in recent years the concept of a circuit and lumped circuit elements have been extended to the optical domains, providing the paradigm of optical metatronics, i.e., metamaterial-inspired optical nanocircuitry, as a powerful tool for design and study of more complex systems at the nanoscale. In this paper we present a design for a new metatronic element, namely, a metatronic transistor that functions as an amplifier. As shown by our analytical and numerical paper here, this metatronic transistor provides gain as well as isolation between the input and output ports of such two-port device. The cascadability and fan-out aspects of this element are also explored.

  11. Parton Fragmentation Functions

    CERN Document Server

    Metz, Andreas

    2016-01-01

    The field of fragmentation functions of light quarks and gluons is reviewed. In addition to integrated fragmentation functions, attention is paid to the dependence of fragmentation functions on transverse momenta and on polarization degrees of freedom. Higher-twist and di-hadron fragmentation functions are considered as well. Moreover, the review covers both theoretical and experimental developments in single-inclusive hadron production in electron-positron annihilation, deep-inelastic lepton-nucleon scattering, and proton-proton collisions.

  12. Optimal cloning of PCR fragments by homologous recombination in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Ana Paula Jacobus

    Full Text Available PCR fragments and linear vectors containing overlapping ends are easily assembled into a propagative plasmid by homologous recombination in Escherichia coli. Although this gap-repair cloning approach is straightforward, its existence is virtually unknown to most molecular biologists. To popularize this method, we tested critical parameters influencing the efficiency of PCR fragments cloning into PCR-amplified vectors by homologous recombination in the widely used E. coli strain DH5α. We found that the number of positive colonies after transformation increases with the length of overlap between the PCR fragment and linear vector. For most practical purposes, a 20 bp identity already ensures high-cloning yields. With an insert to vector ratio of 2:1, higher colony forming numbers are obtained when the amount of vector is in the range of 100 to 250 ng. An undesirable cloning background of empty vectors can be minimized during vector PCR amplification by applying a reduced amount of plasmid template or by using primers in which the 5' termini are separated by a large gap. DpnI digestion of the plasmid template after PCR is also effective to decrease the background of negative colonies. We tested these optimized cloning parameters during the assembly of five independent DNA constructs and obtained 94% positive clones out of 100 colonies probed. We further demonstrated the efficient and simultaneous cloning of two PCR fragments into a vector. These results support the idea that homologous recombination in E. coli might be one of the most effective methods for cloning one or two PCR fragments. For its simplicity and high efficiency, we believe that recombinational cloning in E. coli has a great potential to become a routine procedure in most molecular biology-oriented laboratories.

  13. The development of DUV chemically amplified resists

    Energy Technology Data Exchange (ETDEWEB)

    Thackeray, J.W.; Fedynyshyn, T.H.; Small, R.D. [Shipley Co. Inc., Marlboro, MA (United States)

    1993-12-31

    The development of deep ultraviolet (DUV) resists has necessitated the introduction of new concepts in resist materials and chemistry. Successful DUV resist systems now employ the concept of chemical amplification. This catalytic reaction leads to a substantial enhancement in the imaging dose. Another benefit of chemical amplified resists is that they allow the design of materials which can be transparent to DUV exposure wavelengths, yet they can still have high sensitivity. Commercial and prototype positive- and negative-tone resists are now readily available and these resists have been used in pilot production to make the most advanced integrated circuits with {le}0.35 {mu}m design rules. At Shipley, we have undertaken to develop both negative- and positive-tone chemically amplified resists for DUV lithography. These resists are capable of high resolution (0.3 {mu}m), fast photospeed ({le}30 mJ/sq. cm), and excellent etch resistance. This presentation will discuss the chemical and lithographic properties of the Shipley negative- and positive-tone DUV chemically amplified resists. General discussion of the importance of activation energy for the catalytic process, catalytic chain length, and environmental stability will be given.

  14. The Gain Dependence of the Power Transient in Raman Amplifier

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    It is observed that the amplitude of the power transient overshoot depends on the gain of the amplifier when the input signal powers are the same. The other system parameters, such as the input pump power and fiber length, have no effects on it.

  15. Semiconductor DC amplifier AEP 1487

    International Nuclear Information System (INIS)

    A semiconductor dc amplifier has been designed with the object of achieving low drift without component selection or special temperature-balancing adjustments. Modulator and ac-amplifier techniques have been adopted in order to avoid the drifts that occur when transistors are directly coupled. The diode-ring modulator described in CREL-902 has been used as the input chopper. (author)

  16. Estimation of genome length

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The genome length is a fundamental feature of a species. This note outlined the general concept and estimation method of the physical and genetic length. Some formulae for estimating the genetic length were derived in detail. As examples, the genome genetic length of Pinus pinaster Ait. and the genetic length of chromosome Ⅵ of Oryza sativa L. were estimated from partial linkage data.

  17. Giant optical gain in a rare-earth-ion-doped waveguide amplifier

    NARCIS (Netherlands)

    Geskus, D.; Aravazhi, S.; Garcia Blanco, S.M.; Pollnau, M.

    2011-01-01

    For optical amplification, typically rare-earth-ion (RE) doped fiber amplifiers (RDFA) or semiconductor optical amplifiers (SOAs) are selected. Despite the weak transition cross-sections of RE ions and their low doping level in silica fibers, resulting in very low gain per unit length, the extremely

  18. Modification of the full-length cDNA clone of Newcastle disease virus Isolated from an outbreak In the goose

    Institute of Scientific and Technical Information of China (English)

    LIU Yuliang; HU Shunli; ZHANG Yanmei; WU Yantao; LIU Xiufan; R(o)emer-Oberdoerfer Angela; Veits Jutta; Lange Martina

    2006-01-01

    A 6.5-kb specific fragment containing the T7 promoter and the transcription vector was excised from the full-length eDNA clone of the Newcastle disease virus (NDV) strain ZJI of goose origin,and thereafter it was self-ligated to form a high quality plasmid for mutagenesis.Site-directed mutagenesis was used for inserting three additional G nucleotides (nts) into the region between the T7 promoter and the leader sequence of the NDV genome.RT-PCR was employed to amplify the F/HN gene fragments,and then they were ligated by the shared restriction enzyme BsmBI.Finally,the corresponding fragment in the mutant full-length eDNA was substituted with the new one.The sequencing results showed that the three additional Gnts were successfully inserted and the mutant nts in the full-length eDNA were corrected.This study lays a good foundation for research on the reverse genetics of NDV strain ZJI.

  19. Small signal microwave amplifier design

    CERN Document Server

    Grosch, Theodore

    2000-01-01

    This book explains techniques and examples for designing stable amplifiers for high-frequency applications in which the signal is small and the amplifier circuit is linear. An in-depth discussion of linear network theory provides the foundation needed to develop actual designs. Examples throughout the book will show you how to apply the knowledge gained in each chapter leading to the complex design of low noise amplifiers. Many exercises at the end of each chapter will help students to practice their skills. The solutions to these design problems are available in an accompanying solutions book

  20. International Standardization Activities for Optical Amplifiers

    Institute of Scientific and Technical Information of China (English)

    Haruo Okamura

    2003-01-01

    International standardization activities for Optical Amplifiers at IECTC86 and ITU-T SG15 are reviewed. Current discussions include Optical Amplifier safety guideline, Reliability standard, Rest methods of Noise and PMD, Definitions of Raman amplifier parameters and OA classification.

  1. Broadband amplified spontaneous emission from Er3+-doped single-mode tellurite fibre

    Institute of Scientific and Technical Information of China (English)

    Chen Dong-Dan; Zhang Qin-Yuan; Liu Yue-Hui; Xu Shan-Hui; Yang Zhong-Min; Deng Zai-De; Jiang Zhong-Hong

    2006-01-01

    This paper reports on the fabrication and characterization of a newly erbium-doped single-mode tellurite glass-fibre applicable for 1.5-μm optical amplifiers. A very broad erbium amplified spontaneous emission in the range 1450-1650 nm from erbium-doped single-mode tclluritc glass-fibre is obtained upon excitation of a 980-nm laser diode. The effects of the length of glass-fibre and the pumping power of laser diode on the amplified spontaneous emission are discussed.The result indicates that the tellurite glass-fibre is a promising candidate for designing fibre-optic amplifiers and lasers.

  2. DNA fragmentation in apoptosis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Cleavage of chromosomal DNA into oligonucleosomal size fragments is an integral part of apoptosis. Elegant biochemical work identified the DNA fragmentation factor (DFF) as a major apoptotic endonuclease for DNA fragmentation in vitro. Genetic studies in mice support the importance of DFF in DNA fragmentation and possibly in apoptosis in vivo. Recent work also suggests the existence of additional endonucleases for DNA degradation. Understanding the roles of individual endonucleases in apoptosis, and how they might coordinate to degrade DNA in different tissues during normal development and homeostasis, as well as in various diseased states, will be a major research focus in the near future.

  3. Dispersion-Engineered Traveling Wave Kinetic Inductance Parametric Amplifier

    Science.gov (United States)

    Zmuidzinas, Jonas (Inventor); Day, Peter K. (Inventor)

    2014-01-01

    A traveling wave kinetic inductance parametric amplifier comprises a superconducting transmission line and a dispersion control element. The transmission line can include periodic variations of its dimension along its length. The superconducting material can include a high normal state resistivity material. In some instances the high normal state resistivity material includes nitrogen and a metal selected from the group consisting of titanium, niobium and vanadium. The traveling wave kinetic inductance parametric amplifier is expected to exhibit a noise temperature below 100 mK/GHz.

  4. Fragmentation characteristics analysis of sandstone fragments based on impact rockburst test

    Institute of Scientific and Technical Information of China (English)

    Dongqiao Liu; Dejian Li; Fei Zhao; Chengchao Wang

    2014-01-01

    Impact rockburst test on sandstone samples with a central hole is carried out under true triaxial static loads and vertical dynamic load conditions, and rock fragments after the test are collected. The fragments of sandstone generated from strain rockburst test and uniaxial compression test are also collected. The fragments are weighed and the length, width and thickness of each piece of fragments are measured respectively. The fragment quantities with coarse, medium, fine and micro grains in different size ranges, mass and particles distributions are also analyzed. Then, the fractal dimension of fragments is calculated by the methods of size-frequency, mass-frequency and length-to-thickness ratio-frequency. It is found that the crushing degree of impact rockburst fragments is higher, accompanied with blocky character-istics observably. The mass percentage of small grains, including fine and micro grains, in impact rock-burst test is higher than those in strain rockburst test and uniaxial compression test. Energy dissipation from rockburst tests is more than that from uniaxial compression test, as the quantity of micro grains generated does.

  5. A Transformer Class E Amplifier

    Directory of Open Access Journals (Sweden)

    Mikolajewski Miroslaw

    2014-12-01

    Full Text Available In a high-efficiency Class E ZVS resonant amplifier a matching and isolation transformer can replace some or even all inductive components of the amplifier thus simplifying the circuit and reducing its cost. In the paper a theoretical analysis, a design example and its experimental verification for a transformer Class E amplifier are presented. In the experimental amplifier with a transformer as the only inductive component in the circuit high efficiency ηMAX = 0.95 was achieved for supply voltage VI = 36 V, maximum output power POMAX = 100 W and the switching frequency f = 300 kHz. Measured parameters and waveforms showed a good agreement with theoretical predictions. Moreover, the relative bandwidth of the switching frequency was only 19% to obtain output power control from 4.8 W to POMAX with efficiency not less than 0.9 in the regulation range.

  6. New Packaging for Amplifier Slabs

    Energy Technology Data Exchange (ETDEWEB)

    Riley, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Thorsness, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Suratwala, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Steele, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rogowski, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-03-18

    The following memo provides a discussion and detailed procedure for a new finished amplifier slab shipping and storage container. The new package is designed to maintain an environment of <5% RH to minimize weathering.

  7. Transistor oscillator and amplifier grids

    OpenAIRE

    Weikle, Robert M., II; Kim, Moonil; Hacker, Jonathan B.; De Lisio, Michael P.; Popvić, Zoya B.; Rutledge, David B.

    1992-01-01

    Although quasi-optical techniques are applicable to a large variety of solid-state devices, special attention is given to transistors, which are attractive because they can be used as either amplifiers or oscillators. Experimental results for MESFET bar-grid and planar grid oscillators are presented. A MESFET grid amplifier that receives only vertically polarized waves at the input and radiates horizontally polarized waves at the output is discussed. These planar grids can be scaled for opera...

  8. A KIND OF NEW AMPLIFIER

    Institute of Scientific and Technical Information of China (English)

    YIN XUN-HE; FENG RU-PENG; REN YONG

    2000-01-01

    Chaotic characteristics in the iteration of logistic map (one-dimensional discrete dynamic system) are simulatedand analyzed. The circuit implementation of a kind of chaotic amplifier model is based on the chaotic characteristicsthat chaos is sensitively dependent on its initial conditions, and the circuit simulation result is given using simulationprogram with integrated circuit emphasis for personal computer (PSPICE), and is compared with linear amplifier.Advantages and disadvantages of such a model are indicated.

  9. Casimir force on amplifying bodies

    OpenAIRE

    Sambale, Agnes; Welsch, Dirk-Gunnar; Buhmann, Stefan Yoshi; Dung, Ho Trung

    2009-01-01

    Based on a unified approach to macroscopic QED that allows for the inclusion of amplification in a limited space and frequency range, we study the Casimir force as a Lorentz force on an arbitrary partially amplifying system of linearly locally responding (isotropic) magnetoelectric bodies. We demonstrate that the force on a weakly polarisable/magnetisable amplifying object in the presence of a purely absorbing environment can be expressed as a sum over the Casimir--Polder forces on the excite...

  10. Genetic Differentiation of Archachatina marginata Populations from Three Vegetation Zones Using Radom Amplified Polymorphic DNA Polymerase Chain Reaction

    Directory of Open Access Journals (Sweden)

    Comfort O. AFOLAYAN

    2015-09-01

    Full Text Available The genetic differentiation of Archachatina marginata populations from three different zones of Nigeria was studied with a view to delimiting them into sub-species. One hundred and nineteen (119 snail specimens were collected, comprising of forty (40 specimens from Yenagoa (Mangrove forest and from Kabba (Guinea Savanna and thirty nine (39 specimens were from Ile-Ife (Rainforest. Eight parameters of the shell specimens of A. marginata which included height of shell, width of shell, aperture height, aperture width, spire length, spire width, penultimate whorl length and first whorl length were subjected to Principal Component Analysis (PCA and Canonical Variates Analysis (CVA to delimit the populations into sub-species. DNA of the various populations was extracted from the foot muscle using CTAB (Cetyl Trimethyl Ammonium Bromide method, which was subjected to RAPD analysis. The RAPD studies employed five (5 oligonucleotide primers (OPB – 17, OPH – 12, OPH – 17, OPI – 06 and OPU – 14 to amplify DNA from 27 samples of A. marginata selected. All five primers produced different band patterns, and the number of fragments amplified per primer varied. Among them, OPB- 17 gave DNA profiles with more numerous bands than the others primers. Both PCA and CVA produced overlapped clusters of A. marginata specimens from the three vegetation zones. The height of shell was observed to be the most variable feature and preferably the most suitable parameter for population grouping. Analysis of the proportions of polymorphic loci and band sharing based on similarity indices for A. marginata samples indicated a relatively high level of genetic variation in the populations from the three areas.

  11. Flying between sky islands: the effect of naturally fragmented habitat on butterfly population structure.

    Directory of Open Access Journals (Sweden)

    Sandhya Sekar

    Full Text Available High elevation montane areas are called "sky islands" when they occur as a series of high mountains separated by lowland valleys. Different climatic conditions at high elevations makes sky islands a specialized type of habitat, rendering them naturally fragmented compared to more continuous habitat at lower elevations. Species in sky islands face unsuitable climate in the intervening valleys when moving from one montane area to another. The high elevation shola-grassland mosaic in the Western Ghats of southern India form one such sky island complex. The fragmented patches make this area ideal to study the effect of the spatial orientation of suitable habitat patches on population genetic structure of species found in these areas. Past studies have suggested that sky islands tend to have genetically structured populations, possibly due to reduced gene flow between montane areas. To test this hypothesis, we adopted the comparative approach. Using Amplified Fragment Length Polymorphisms, we compared population genetic structures of two closely related, similar sized butterfly species: Heteropsis oculus, a high elevation shola-grassland specialist restricted to the southern Western Ghats, and Mycalesis patnia, found more continuously distributed in lower elevations. In all analyses, as per expectation the sky island specialist H. oculus exhibited a greater degree of population genetic structure than M. patnia, implying a difference in geneflow. This difference in geneflow in turn appears to be due to the natural fragmentation of the sky island complexes. Detailed analysis of a subset of H. oculus samples from one sky island complex (the Anamalais showed a surprising genetic break. A possible reason for this break could be unsuitable conditions of higher temperature and lower rainfall in the intervening valley region. Thus, sky island species are not only restricted by lack of habitat continuity between montane areas, but also by the nature of the

  12. Fragments of Time

    DEFF Research Database (Denmark)

    Christiansen, Steen Ledet

    breaks down as the characters visit and re-visit the same episodes over and over, and we as spectators are never sure whether we are watching a narrative fragment in its "original" version, or one that has been altered. My paper will focus on the spectator's relation to the fragmented narrative that is...

  13. Performance Simulation and Optimization of Er3+/Pr3+ Doped Fiber Amplifiers by Optisystem

    Directory of Open Access Journals (Sweden)

    Jiuru Yang

    2013-01-01

    Full Text Available The joint amplifying system based Erbium Doped Fiber Amplifier (EDFA and Praseodymium Doped Fiber Amplifier (PDFA has been regarded as one of the promising technologies in optical core networks. However, due to the complex structure and high cost, it is unpractical to optimize the performance for these two amplifiers by experiments. In this study, to overcome this problem and enhance the output performance, the operation processes of EDFA and PDFA are modeled by adopting the Optisystem software. Then, according to the spectrum characteristics of the amplifying systems obtained, the analysis in detail is conducted respectively. Consequently, based on the quantitative results in terms of gain, flatness and noises, the optimal parameters with the respect of pumping power and the length of EDF/PDF are determinate and the output performance of these two amplifying system is also improved obviously.

  14. Fragmented Work Stories

    DEFF Research Database (Denmark)

    Humle, Didde Maria; Reff Pedersen, Anne

    2015-01-01

    Following a strand of narrative studies pointing to the living conditions of storytelling and the micro-level implications of working within fragmented narrative perspectives, this article contributes to narrative research on work stories by focusing on how meaning is created from fragmented stor...... of antenarrative practice approach that offers a contemporary method for exploring meaning creation in work stories.......Following a strand of narrative studies pointing to the living conditions of storytelling and the micro-level implications of working within fragmented narrative perspectives, this article contributes to narrative research on work stories by focusing on how meaning is created from fragmented...... stories. We argue that meaning by story making is not always created by coherence and causality; meaning is created by different types of fragmentation: discontinuities, tensions and editing. The objective of this article is to develop and advance antenarrative practice analysis of work stories...

  15. Silicon on Insulator MESFETs for RF Amplifiers.

    Science.gov (United States)

    Wilk, Seth J; Balijepalli, Asha; Ervin, Joseph; Lepkowski, William; Thornton, Trevor J

    2010-03-01

    CMOS compatible, high voltage SOI MESFETs have been fabricated using a standard 3.3V CMOS process without any changes to the process flow. A 0.6μm gate length device operates with a cut-off frequency of 7.3GHz and a maximum oscillation frequency of 21GHz. There is no degradation in device performance up to its breakdown voltage, which greatly exceeds that of CMOS devices on the same process. Other figures of merit of relevance to RF front-end design are presented, including the maximum stable gain and noise figure. An accurate representation of the device in SPICE has been developed using the commercially available TOM3 model. Using the SOI MESFET model, a source degenerated low noise RF amplifier targeting operation near 1GHz has been designed. The amplifier was fabricated on a PCB board and operates at 940MHz with a minimum NF of 3.8dB and RF gain of 9.9dB while only consuming 5mW of DC power. PMID:20657816

  16. Identificación de Cultivares y Líneas de Mejoramiento de Arroz de Chile Mediante Amplificación de Fragmentos Polimórficos (AFLP) Identification of Chilean Rice Cultivars And Breeding Lines by Means of Amplified Fragment Length Polymorphism (AFLP)

    OpenAIRE

    Carlos Aguirre; Roberto Alvarado; Patricio Hinrichsen

    2005-01-01

    Doce cultivares y líneas de arroz (Oryza sativa L.) desarrollados por el programa de fitomejoramiento del Instituto de Investigaciones Agropecuarias (INIA), Centro Regional de Investigación Quilamapu, fueron caracterizados genéticamente mediante amplificación de fragmentos polimórficos (AFLP). De 21 combinaciones ensayadas, sólo 16 fueron informativas, generando un total de 667 amplicones, 94 de ellos polimórficos (14,4%), con un rango entre 9 y 33% de polimorfismo por combinación. Esto indic...

  17. Low-Noise Band-Pass Amplifier

    Science.gov (United States)

    Kleinberg, L.

    1982-01-01

    Circuit uses standard components to overcome common limitation of JFET amplifiers. Low-noise band-pass amplifier employs JFET and operational amplifier. High gain and band-pass characteristics are achieved with suitable choice of resistances and capacitances. Circuit should find use as low-noise amplifier, for example as first stage instrumentation systems.

  18. Post-Fragmentation Whole Genome Amplification-Based Method

    Science.gov (United States)

    Benardini, James; LaDuc, Myron T.; Langmore, John

    2011-01-01

    This innovation is derived from a proprietary amplification scheme that is based upon random fragmentation of the genome into a series of short, overlapping templates. The resulting shorter DNA strands (DNA fragments with defined 3 and 5 termini. Specific primers to these termini are then used to isothermally amplify this library into potentially unlimited quantities that can be used immediately for multiple downstream applications including gel eletrophoresis, quantitative polymerase chain reaction (QPCR), comparative genomic hybridization microarray, SNP analysis, and sequencing. The standard reaction can be performed with minimal hands-on time, and can produce amplified DNA in as little as three hours. Post-fragmentation whole genome amplification-based technology provides a robust and accurate method of amplifying femtogram levels of starting material into microgram yields with no detectable allele bias. The amplified DNA also facilitates the preservation of samples (spacecraft samples) by amplifying scarce amounts of template DNA into microgram concentrations in just a few hours. Based on further optimization of this technology, this could be a feasible technology to use in sample preservation for potential future sample return missions. The research and technology development described here can be pivotal in dealing with backward/forward biological contamination from planetary missions. Such efforts rely heavily on an increasing understanding of the burden and diversity of microorganisms present on spacecraft surfaces throughout assembly and testing. The development and implementation of these technologies could significantly improve the comprehensiveness and resolving power of spacecraft-associated microbial population censuses, and are important to the continued evolution and advancement of planetary protection capabilities. Current molecular procedures for assaying spacecraft-associated microbial burden and diversity have inherent sample loss issues at

  19. Gain Characteristics of Fiber Optical Parametric Amplifier

    Institute of Scientific and Technical Information of China (English)

    高明义; 姜淳; 胡卫生

    2004-01-01

    The theory model of fiber optical parametric amplifier (FOPA) was introduced, which is based on optical nonlinear effect. And then numerical simulation was done to analyze and discuss the gain spectral characteristics of one-pump and two-pump FOPA. The results show that for one-pump FOPA, when pump wavelength is near to fiber zero-dispersion wavelength(ZDW), the gain flatness is better, and with the increase of the pump power, fiber length and its nonlinear coefficient, the gain value will increase while the gain bandwidth will become narrow. For two-pump FOPA, when the pump central wavelength is near to fiber ZDW, the gain flatness is better. Moreover, by decreasing the space of two pumps wavelength, the gain flatness can be improved. Finally, some problems existing in FOPA were addressed.

  20. EMI-resilient amplifier circuits

    CERN Document Server

    van der Horst, Marcel J; Linnenbank, André C

    2014-01-01

    This book enables circuit designers to reduce the errors introduced by the fundamental limitations and electromagnetic interference (EMI) in negative-feedback amplifiers.  The authors describe a systematic design approach for application specific negative-feedback amplifiers, with specified signal-to-error ratio (SER).  This approach enables designers to calculate noise, bandwidth, EMI, and the required bias parameters of the transistors used in  application specific amplifiers in order to meet the SER requirements.   ·         Describes design methods that incorporate electromagnetic interference (EMI) in the design of application specific negative-feedback amplifiers; ·         Provides designers with a structured methodology to avoid the use of trial and error in meeting signal-to-error ratio (SER) requirements; ·         Equips designers to increase EMI immunity of the amplifier itself, thus avoiding filtering at the input, reducing the number of components and avoiding detr...

  1. Spectroscopic amplifier for pin diode

    International Nuclear Information System (INIS)

    The photodiode remains the basic choice for the photo-detection and is widely used in optical communications, medical diagnostics and field of corpuscular radiation. In detecting radiation it has been used for monitoring radon and its progeny and inexpensive spectrometric systems. The development of a spectroscopic amplifier for Pin diode is presented which has the following characteristics: canceler Pole-Zero (P/Z) with a time constant of 8 μs; constant gain of 57, suitable for the acquisition system; 4th integrator Gaussian order to waveform change of exponential input to semi-Gaussian output and finally a stage of baseline restorer which prevents Dc signal contribution to the next stage. The operational amplifier used is the TLE2074 of BiFET technology of Texas Instruments with 10 MHz bandwidth, 25 V/μs of slew rate and a noise floor of 17 nv/(Hz)1/2. The integrated circuit has 4 operational amplifiers and in is contained the total of spectroscopic amplifier that is the goal of electronic design. The results show like the exponential input signal is converted to semi-Gaussian, modifying only the amplitude according to the specifications in the design. The total system is formed by the detector, which is the Pin diode, a sensitive preamplifier to the load, the spectroscopic amplifier that is what is presented and finally a pulse height analyzer (Mca) which is where the spectrum is shown. (Author)

  2. 利用12S rRNA基因的限制性酶切末端片段长度多态性鉴定动物种类%Identification of Animal Species by Terminal Restriction Fragment Length Polymorphism (T-RFLP) of Mitochondrial 12S rRNA Gene

    Institute of Scientific and Technical Information of China (English)

    汪琦; 张昕; 赵大贺; 马海萍; 陈广全; 张惠媛

    2010-01-01

    目的:建立一种精确可靠的鉴定常见的10种动物(猪、狗、牛、山羊、绵羊、马、鸡、鼠、三文鱼和鹿)的方法.方法:利用12S rRNA基因的限制性酶切末端片段长度多态性(terminal restriction fragment length polymorphism,T-RFLP)鉴别动物种类.将线粒体12S rRNA基因通过引物的5'端用FAM荧光标记,从基因组DNA中扩增450bp的目的片段.引物对1(下游引物FAM标记,上游引物不标记)扩增的PCR产物用限制性内切酶Alu Ⅰ酶切.引物对2(上游引物FAM标记,下游引物不标记)扩增的PCR产物用限制性内切酶Tru9 Ⅰ酶切.得到的酶切产物分别在遗传分析仪ABI 3100上进行毛细管电泳,片段大小用Peak Scanner 1.0软件分析.结果:根据Alu Ⅰ酶切图谱能够区分鸡、马、猪和三文鱼,而鹿和牛、山羊和绵羊、鼠和狗因酶切图谱相同无法分开.根据Tru9 Ⅰ酶切图谱,能够进一步将鹿和牛、山羊和绵羊、鼠和狗分开.同一种动物不同个体的酶切图谱完全相同,结果具有可重复性.没有出现物种内多态的现象.大多数情况下,实际得到的末端片段长度与理论值非常接近,只存在2~5bp的差异.结论:该方法操作简单、结果精确,适用于鉴定动物种类.

  3. Stratification of gallstone fragments: the key to more effective fragmentation.

    Science.gov (United States)

    Alderfer, J T; Laufer, I; Wisniewski, F; Malet, P F

    1992-04-01

    During previous experiments with in vitro fragmentation in a simulated gallbladder, we noticed that stone fragments tended to stratify with the dust and smaller fragments settled to the dependent portion, while the larger fragments settled on top. We reviewed the oral cholecystogram (OCG) of 10 patients examined 6 months following gallstone lithotripsy. In all cases with adequate visualization of stone fragments, the stratification phenomenon was observed. We hypothesized that adjusting the shock wave focus to target on these large fragments would improve the efficiency of fragmentation. To test this hypothesis, we fragmented three matched pairs of gallstones in vitro. For each pair, the stones were removed from the same gallbladder and the stone weights of the two stones were within 10%. The smaller member of each pair was fragmented using the "old method" with the focus on the fragment line. The larger stone was fragmented with the "new method" with the focus in the acoustic shadow deep to the echogenic line caused by the dust and small fragments in the dependent portion. The distribution of fragments was analyzed by passing the fragments through a series of filters. With the new method of targeting, the proportion of fragments less than 1.5 mm was doubled while the fragments greater than 5 mm were eliminated. The new method of targeting, taking into account the stratification of stone fragments, produces more effective fragmentation and should lead to more rapid clearance of fragments from the gallbladder. PMID:10149180

  4. The nonlinear fragmentation equation

    International Nuclear Information System (INIS)

    We study the kinetics of nonlinear irreversible fragmentation. Here, fragmentation is induced by interactions/collisions between pairs of particles and modelled by general classes of interaction kernels, for several types of breakage models. We construct initial value and scaling solutions of the fragmentation equations, and apply the 'non-vanishing mass flux' criterion for the occurrence of shattering transitions. These properties enable us to determine the phase diagram for the occurrence of shattering states and of scaling states in the phase space of model parameters. (fast track communication)

  5. Optical steganography based on amplified spontaneous emission noise.

    Science.gov (United States)

    Wu, Ben; Wang, Zhenxing; Tian, Yue; Fok, Mable P; Shastri, Bhavin J; Kanoff, Daniel R; Prucnal, Paul R

    2013-01-28

    We propose and experimentally demonstrate an optical steganography method in which a data signal is transmitted using amplified spontaneous emission (ASE) noise as a carrier. The ASE serving as a carrier for the private signal has an identical frequency spectrum to the existing noise generated by the Erbium doped fiber amplifiers (EDFAs) in the transmission system. The system also carries a conventional data channel that is not private. The so-called "stealth" or private channel is well-hidden within the noise of the system. Phase modulation is used for both the stealth channel and the public channel. Using homodyne detection, the short coherence length of the ASE ensures that the stealth signal can only be recovered if the receiver closely matches the delay-length difference, which is deliberately changed in a dynamic fashion that is only known to the transmitter and its intended receiver. PMID:23389187

  6. Isospin in nuclear fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Baran, V. [Bucharest Univ., IFIN-HH (Romania); Baran, V.; Colonna, M.; Di Toro, M. [Catania Univ., Laboratori Nazionali del Sud, INFN (Italy)

    2003-07-01

    The isospin dynamics when we explore various reaction mechanisms at intermediate energies is discussed. We are concerned with its peculiarities in the nuclear liquid-gas phase transition, in mid-rapidity fragment formation for semi-central collisions as well as in the diffusion process in binary, peripheral reactions. The connection of these effects to the density dependence of symmetry energy is analyzed in detail. In this work we showed how various reaction mechanism at Fermi energies can provide complementary information about the density dependence of symmetry term of the nuclear equation of state. In these reactions several observables are sensitive to the isovector channel: i) isospin distillation in multifragmentation, ii) isospin content of neck fragments, iii) iso-scaling parameters, and iv) isospin content of PLF (projectile-like fragments) and TLF (target-like fragments) in peripheral reaction.

  7. Fission fragment rocket concept

    International Nuclear Information System (INIS)

    A new propulsion scheme is outlined which may permit interstellar missions for spacecraft. This scheme is based on the idea of allowing fission fragments to escape from the core of a nuclear reactor. (orig.)

  8. Physics of projectile fragments

    International Nuclear Information System (INIS)

    This is a study report on the polarization phenomena of the projectile fragments produced by heavy ion reactions, and the beta decay of fragments. The experimental project by using heavy ions with the energy from 50 MeV/amu to 250 MeV/amu was designed. Construction of an angle-dispersion spectrograph for projectile fragments was proposed. This is a two-stage spectrograph. The first stage is a QQDQQ type separator, and the second stage is QDQD type. Estimation shows that Co-66 may be separated from the nuclei with mass of 65 and 67. The orientation of fragments can be measured by detecting beta-ray. The apparatus consists of a uniform field magnet, an energy absorber, a stopper, a RF coil and a beta-ray hodoscope. This system can be used for not only this purpose but also for the measurement of hyperfine structure. (Kato, T.)

  9. Fragmentation Main Model

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The fragmentation model combines patch size and patch continuity with diversity of vegetation types per patch and rarity of vegetation types per patch. A patch was...

  10. Gaussian amplifier for nuclear spectrometry

    International Nuclear Information System (INIS)

    One of the major goals of nuclear spectrometry is the determination of the energy spectrum of a radioactive source. To measure this spectrum with electronic instrumentation one need to use a nuclear spectrometry chain of which the amplifier is part of, and whose filter shaping considerably influences the final energy resolution achieved. The amplifier released accomplishes a 7th order Gaussian filter shape with Taylor series approximation synthesized by the Shifted Companion Form and mounted using only electronic components availablein Brazil. The final version has been tested and the results showed a very good performance and the energy resolution achieved was equivalent to the imported models. (Author)

  11. Electroeluting DNA Fragments

    OpenAIRE

    Zarzosa-Álvarez, Ana L.; Sandoval-Cabrera, Antonio; Torres-Huerta, Ana L.; Ma. Bermudez-Cruz, Rosa

    2010-01-01

    Purified DNA fragments are used for different purposes in Molecular Biology and they can be prepared by several procedures. Most of them require a previous electrophoresis of the DNA fragments in order to separate the band of interest. Then, this band is excised out from an agarose or acrylamide gel and purified by using either: binding and elution from glass or silica particles, DEAE-cellulose membranes, "crush and soak method", electroelution or very often expensive commercial purification ...

  12. Landscape Fragmentation in Iceland

    OpenAIRE

    Einar Hjörleifsson 1988

    2014-01-01

    Landscape fragmentation measurements provide baseline data of direct human influence on landscape and habitat systems through land use. In 2011, the European Environment Agency, the EEA and the Swiss Federal Office for the Environment or FOEN created a comprehensive report on the status of landscape fragmentation in 28 European countries, excluding Iceland. This thesis builds on EEA and FOEN methodology in order to create comparable data for Iceland. The Icelandic data set had to be adjusted ...

  13. Computer Aided Design and Analysis of a 2-4 GHz Broadband Balanced Microstrip Amplifier

    Directory of Open Access Journals (Sweden)

    S. H. Ibrahim

    2012-07-01

    Full Text Available In this paper, a computer-aided design and analysis of a 2-4 GHz broadband balanced microstrip amplifier using a full computer simulation program developed by the author and others is presented. A short and efficient CAD procedure for broadband amplifier design is introduced. The first step is to design an initial narrow-band high gain microstrip amplifier at 3-GHz central frequency. The second step is to optimize the initial lengths and widths of the input and output microstrip-matching circuits to get the broadband amplifier over the range 2-4 GHz. The analysis of both narrow and broadband amplifiers is investigated. In addition, with the design and analysis of a low-pass microstrip filter, the paper introduces the design and analysis of a Lange coupler. The final AC schematic diagram of the designed amplifier with the lengths and widths of microstrip lines is presented.Key Words: Computer-Aided Design and Analysis, Microstrip Amplifier, Microwave Amplifier.

  14. Individual Telomere Lengths in Chronic Myeloid Leukemia

    Directory of Open Access Journals (Sweden)

    Oumar Samassekou

    2009-11-01

    Full Text Available Chronic myeloid leukemia (CML is a neoplasia characterized by proliferation of a myeloid cell lineage and chromosome translocation t(9;22 (q34;q11.2. As in the case of most cancers, the average telomere length in CML cells is shorter than that in normal blood cells. However, there are currently no data available concerning specific individual telomere length in CML. Here, we studied telomere length on each chromosome arm of CML cells. In situ hybridization with peptide nucleic acid probes was performed on CML cells in metaphase. The fluorescence intensity of each specific telomere was converted into kilobases according to the telomere restriction fragment results for each sample. We found differences in telomere length between short arm ends and long arm ends. We observed recurrent telomere length changes as well as telomere length maintenance and elongation in some individual telomeres. We propose a possible involvement of individual telomere length changes to some chromosomal abnormalities in CML. We suggest that individual telomere length maintenance is chromosome arm-specific associated with leukemia cells.

  15. A wideband dc-coupled amplifier

    International Nuclear Information System (INIS)

    A method is described whereby an ac-coupled high-frequency amplifier and a dc-coupled low-frequency amplifier are connected in parallel in order to obtain a dc-coupled wideband amplifier. By using an operational amplifier which compares the output voltage with the input voltage, the low-frequency amplifier contributes to the overall gain only when the gain of the ac-coupled amplifier droops at low frequencies. Thus, no frequency splitting networks are necessary and the excellent low-frequency features of an operational amplifier are added to those of the ac-coupled wideband amplifier. As an example, a low noise amplifier is described which exhibits a hundredfold gain, a bandwidth from dc to 550 MHz, an input bias current of less than 1 nA, and an output voltage range of ±1 V

  16. Features of thermal adsorption spectroscopy to find the size distribution of biological polymers and their fragments

    International Nuclear Information System (INIS)

    The work deals with the determination of various biopolymer fragments' distribution (DNA and proteins) by their size on the basis of thermal adsorption technique. New features of thermal adsorption spectroscopy with the determination of the length of the DNA fragments and proteins, also analysis of the role of buffer solution in the thermal desorption of biopolymer fragments have been found. (authors)

  17. Characterisation Of Low Noise Amplifier

    Directory of Open Access Journals (Sweden)

    MAULIK B.PATEL

    2012-08-01

    Full Text Available Amplification is one of the most basic and prevalent microwave circuit functions inmodern RF and microwave systems. Early microwave amplifiers relied on tubes, such asklystrons and traveling-wave tubes, or solid-state reflection amplifiers based on thenegative resistance characteristics of tunnel or varactor diodes. But due to the dramaticimprovements and innovations in solid-state technology that have occurred since the1970s, most RF and microwave amplifiers today use transistor devices such as Si or SiGeBJTs, GaAs HBTs, GaAs or InP FETs, or GaAs HEMTs. Microwave transistor amplifiersare rugged, low-cost, reliable, and can be easily integrated in both hybrid andmonolithic integrated circuitry. Transistor amplifiers can be used at frequencies inexcess of 100 GHz in a wide range of applications requiring small size, low-noise figure,broad bandwidth, and low to medium power capacity. Although microwave tubes are stillrequired for very high power and/or very high frequency applications, continuingimprovement in the performance of microwave transistors is steadily reducing the needfor microwave tubes

  18. HIERARCHICAL FRAGMENTATION OF THE ORION MOLECULAR FILAMENTS

    International Nuclear Information System (INIS)

    We present a high angular resolution map of the 850 μm continuum emission of the Orion Molecular Cloud-3 (OMC 3) obtained with the Submillimeter Array (SMA); the map is a mosaic of 85 pointings covering an approximate area of 6.'5 × 2.'0 (0.88 × 0.27 pc). We detect 12 spatially resolved continuum sources, each with an H2 mass between 0.3-5.7 M ☉ and a projected source size between 1400-8200 AU. All the detected sources are on the filamentary main ridge (nH2≥106 cm–3), and analysis based on the Jeans theorem suggests that they are most likely gravitationally unstable. Comparison of multi-wavelength data sets indicates that of the continuum sources, 6/12 (50%) are associated with molecular outflows, 8/12 (67%) are associated with infrared sources, and 3/12 (25%) are associated with ionized jets. The evolutionary status of these sources ranges from prestellar cores to protostar phase, confirming that OMC-3 is an active region with ongoing embedded star formation. We detect quasi-periodical separations between the OMC-3 sources of ≈17''/0.035 pc. This spatial distribution is part of a large hierarchical structure that also includes fragmentation scales of giant molecular cloud (≈35 pc), large-scale clumps (≈1.3 pc), and small-scale clumps (≈0.3 pc), suggesting that hierarchical fragmentation operates within the Orion A molecular cloud. The fragmentation spacings are roughly consistent with the thermal fragmentation length in large-scale clumps, while for small-scale cores it is smaller than the local fragmentation length. These smaller spacings observed with the SMA can be explained by either a helical magnetic field, cloud rotation, or/and global filament collapse. Finally, possible evidence for sequential fragmentation is suggested in the northern part of the OMC-3 filament.

  19. Electrostatic turbulence with finite parallel correlation length and radial diffusion

    International Nuclear Information System (INIS)

    Particle diffusion in a given electrostatic turbulence with a finite correlation length along the confining magnetic field is studied in the test particle approach. An anomalous diffusion regime with amplified diffusion coefficient is found under the conditions when trajectory trapping in the structure of the stochastic potential is effective. (author)

  20. Performance analysis of a concatenated erbium-doped fiber amplifier supporting four mode groups

    Science.gov (United States)

    Qin, Zujun; Fan, Di; Zhang, Wentao; Xiong, Xianming

    2016-05-01

    An erbium-doped fiber amplifier (EDFA) supporting four mode groups has been theoretically designed by concatenating two sections of erbium-doped fibers (EDFs). Each EDF has a simple erbium doping profile for the purpose of reducing its fabrication complexity. We propose a modified genetic algorithm (GA) to provide detailed investigations on the concatenated amplifier. Both the optimal fiber length and erbium doping radius in each EDF have been found to minimize the gain difference between signal modes. Results show that the parameters of the central-doped EDF have a greater impact on the amplifier performance compared to those of the annular-doped one. We then investigate the influence of the small deviations of the erbium fiber length, doping radius and doping concentration of each EDF from their optimal values upon the amplifier performance, and discuss their design tolerances in obtaining a desirable amplification characteristics.

  1. Low Cost RF Amplifier for Community TV

    Science.gov (United States)

    Ch, Syafaruddin; Sasongko, Sudi Mariyanto Al; Made Budi Suksmadana, I.; Mustiko Okta Muvianto, Cahyo; Ariessaputra, Suthami

    2016-01-01

    he capability of television to deliver audio video makes this media become the most effective method to spread information. This paper presents an experiment of RF amplifier design having low-cost design and providing sufficient RF power particularly for community television. The RF amplifier consists of two stages of amplifier. The first stage amplifier was used to leverage output of TV modulator from 11dBm to enable to drive next stage amplifier. CAD simulation and fabrication were run to reach optimum RF amplifier design circuit. The associated circuit was made by determining stability circle, stability gain, and matching impedance. Hence, the average power of first stage RF amplifier was 24.68dBm achieved. The second stage used RF modules which was ready match to 50 ohm for both input and output port. The experiment results show that the RF amplifier may operate at frequency ranging from 174 to 230MHz. The average output power of the 2nd stage amplifier was 33.38 Watt with the overall gain of 20.54dB. The proposed RF amplifier is a cheap way to have a stable RF amplifier for community TV. The total budget for the designed RF amplifier is only a 1/5 compared to local design of final TV amplifier.

  2. Wavelength-Dependent Transient Characteristics Caused by Gain Saturation in Highly Nonlinear Fiber-Based Raman Amplifiers

    Institute of Scientific and Technical Information of China (English)

    Shinobu; Tamaoki; Tetsufumi; Tsuzaki; Motoki; Kakui; Masayuki; Shigematsu

    2003-01-01

    We have investigated the transient characteristics of discrete Raman Amplifiers and found that the response time caused by gain saturation is dependent upon the wavelength, which corresponds to the effective length of the pump light.

  3. Fragment screening: an introduction.

    Science.gov (United States)

    Leach, Andrew R; Hann, Michael M; Burrows, Jeremy N; Griffen, Ed J

    2006-09-01

    There are clearly many different philosophies associated with adapting fragment screening into mainstream Drug Discovery Lead Generation strategies. Scientists at Astex, for instance, focus entirely on strategies involving use of X-ray crystallography and NMR. However, AstraZeneca uses a number of different fragment screening strategies. One approach is to screen a 2000 compound fragment set (with close to "lead-like" complexity) at 100 microM in parallel with every HTS such that the data are obtained on the entire screening collection at 10 microM plus the extra samples at 100 microM; this provides valuable compound potency data in a concentration range that is usually unexplored. The fragments are then screen-specific "privileged structures" that can be searched for in the rest of the HTS output and other databases as well as having synthesis follow-up. A typical workflow for a fragment screen within AstraZeneca is shown below (Figure 24) and highlights the desirability (particularly when screening >100 microM) for NMR and X-ray information to validate weak hits and give information on how to optimise them. In this chapter, we have provided an introduction to the theoretical and practical issues associated with the use of fragment methods and lead-likeness. Fragment-based approaches are still in an early stage of development and are just one of many interrelated techniques that are now used to identify novel lead compounds for drug development. Fragment based screening has some advantages, but like every other drug hunting strategy will not be universally applicable. There are in particular some practical challenges associated with fragment screening that relate to the generally lower level of potency that such compounds initially possess. Considerable synthetic effort has to be applied for post-fragment screening to build the sort of potency that would be expected to be found from a traditional HTS. However, if there are no low-hanging fruit in a screening

  4. Optical architecture for a multi-megajoule ICF driver incorporating megajoule class KrF amplifiers

    International Nuclear Information System (INIS)

    A gaseous amplifying medium should be scalable to any arbitrary size. A system architecture is reported which will produce 10 MJ with only four amplifiers in the last stage by making use of this scalability. The system described uses optical angular multiplexing for efficient utilization of such large KrF amplifiers. For such large amplifiers, each multiplex beamline carries 16 kJ toward the target chamber. This is because the pump duration need only be increased as the cube root of the output energy and is only 2050 ns. While the use of angular multiplexing does not increase the total count of beamlines, it does increase their length since space has to be provided for the temporal decoder; a possible site plan is shown. Optical beam tubes are filled with He to avoid propagation problems and to promote cleanliness. Single shot sacrificial windows are proposed for large amplifiers. Relatively large multiplexing angles reduce crosstalk to a manageable level

  5. Influences of finite gain bandwidth on pulse propagation in parabolic fiber amplifiers with distributed gain profiles

    Institute of Scientific and Technical Information of China (English)

    Zhao Jia-Sheng; Li Pan; Chen Xiao-Dong; Feng Su-Juan; Mao Qing-He

    2012-01-01

    The evolutions of the pulses propagating in decreasing and increasing gain distributed fiber amplifiers with finite gain bandwidths are investigated by simulations with the nonlinear Schrodinger equation.The results show that the parabolic pulse propagations in both the decreasing and the increasing gain amplifiers are restricted by the finite gain bandwidth.For a given input pulse,by choosing a small initial gain coefficient and gain variation rate,the whole gain for the pulse amplification limited by the gain bandwidth may be higher,which is helpful for the enhancement of the output linearly chirped pulse energy.Compared to the decreasing gain distributed fiber amplifier,the increasing gain distributed amplifier may be more conducive to suppress the pulse spectral broadening and increase the critical amplifier length for achieving a larger output linearly chirped pulse energy.

  6. Fragmentation and lethality

    Directory of Open Access Journals (Sweden)

    V. R. Thiruvenkatachar

    1958-04-01

    Full Text Available "The lethality of a H.E. shell or bomb depends on its ability to produce high velocity fragments and blast. The relative importance of these two damaging agents depends on the nature of the targets it is proposed to destroy. Small, high-velocity fragments are effective for the attack of personnel in the open, but aircraft targets require larger fragments. The blast effect from shell-burst inside aircraft wings does considerable damage, but blast is of relatively little importance against heavily armoured targets such as tanks. Fragment effect ceases to be of primary importance here and if the HE shell is to be lethal to such targets it must carry a very large charge of explosive, which will either ""scab"" the armour or do extensive structural damage by blast and shock. For assessing the effectiveness of a fragmenting shell or bomb against a given type of target, we have to take into account different characteristics of ammunition and target. The solution of the problem of lethality of ammunition will involve a determination of fragmentation in regard to total number of a design with a specific level of lethality in a given situation, it will be necessary to predict the performance for given design data, a process which demands a theoretical treatment if possible, or at least a sufficient quantity of experimental data which can yield reliable empirical formulae. In this paper an account is given of the various theoretical and empirical aspects and a discussion of these with reference to certain special cases. "

  7. IMPACT fragmentation model developments

    Science.gov (United States)

    Sorge, Marlon E.; Mains, Deanna L.

    2016-09-01

    The IMPACT fragmentation model has been used by The Aerospace Corporation for more than 25 years to analyze orbital altitude explosions and hypervelocity collisions. The model is semi-empirical, combining mass, energy and momentum conservation laws with empirically derived relationships for fragment characteristics such as number, mass, area-to-mass ratio, and spreading velocity as well as event energy distribution. Model results are used for several types of analysis including assessment of short-term risks to satellites from orbital altitude fragmentations, prediction of the long-term evolution of the orbital debris environment and forensic assessments of breakup events. A new version of IMPACT, version 6, has been completed and incorporates a number of advancements enabled by a multi-year long effort to characterize more than 11,000 debris fragments from more than three dozen historical on-orbit breakup events. These events involved a wide range of causes, energies, and fragmenting objects. Special focus was placed on the explosion model, as the majority of events examined were explosions. Revisions were made to the mass distribution used for explosion events, increasing the number of smaller fragments generated. The algorithm for modeling upper stage large fragment generation was updated. A momentum conserving asymmetric spreading velocity distribution algorithm was implemented to better represent sub-catastrophic events. An approach was developed for modeling sub-catastrophic explosions, those where the majority of the parent object remains intact, based on estimated event energy. Finally, significant modifications were made to the area-to-mass ratio distribution to incorporate the tendencies of different materials to fragment into different shapes. This ability enabled better matches between the observed area-to-mass ratios and those generated by the model. It also opened up additional possibilities for post-event analysis of breakups. The paper will discuss

  8. Fission Fragments Discriminator

    International Nuclear Information System (INIS)

    Nuclear fission reaction between Uranium-235 nucleus and thermal neutron caused the high energy fission fragments with uncertainly direction. The particle direction discrimination was determined. The 2.5 x 3.0 mm2 polyethylene gratings with 1-6 mm thickness were used. The grating was placed between uranium screen that fabricated from ammonium-diurinate compound and polycarbonate nuclear track film recorder irradiated by neutron from Thai Research Reactor (TRR-1/M1) facility. The nuclear track density was inversely with grating thickness. It's only fission fragments normal to uranium screen pass through film recorder when grating thickness was 4-6 mm

  9. Fragmentation of kidney stones

    International Nuclear Information System (INIS)

    Complete text of publication follows. Fragmentation, i.e. the breaking of particulate materials into smaller pieces is abundant in nature and underlies several industrial processes, which attracted a continuous interest in scientific and engineering research over the past decades. In industrial applications, fragmentation processes are mostly used for the comminution of ores in various types of mills. Kidney stone is a well known human dis- ease which embitters the life of many people (in a country like the USA about 106 cases are registered yearly). In order to extract large kidney stones (diameter ≥ 1 cm) from the human body without operation, one of the most efficient treatment is the fragmentation of kidney stones by the so-called extracorporal shock wave lithography method: a shock wave penetrating the human body is generated by an electric pulse. The repeated application of the shock wave gradually fragments the stones into pieces of size ≤ 2 mm which then leave the body through the urine system. Recently, a novel type of lithographic method has been suggested by using widely focused shock waves which fragment the stones by a squeezing mechanism. Laboratory experiments showed that the widely focused squeezing waves achieve a higher fragmentation efficiency than the frequently used shock waves of sharp focus. Based on this method a novel medical treatment can be introduced which is less demanding for the patients. Before the application of the method in the clinical practice a detailed understanding of the fragmentation mechanism of kidney stones due to shock waves is required. Since analytic theoretical methods have serious limitations in this field, we develop a realistic model of the mechanical behavior of kidney stones and a simulation code which makes possible to study the mechanism of breakup under various external conditions. Computer simulations in two dimensions have revealed a peculiar way of crack formation, i.e. the crack which finally breaks

  10. Amplifying the evanescent field of free electrons

    OpenAIRE

    So, J.-K.; Ou, J.-Y.; Adamo, G.; García de Abajo, F. J.; MacDonald, K. F.; Zheludev, N.I.

    2013-01-01

    We provide the first experimental demonstration that the evanescent field of free electrons can be amplified by a plasmonic nanolayer in much that same way as optical evanescent fields are amplified in the ‘poor-man’s superlens’.

  11. Amplifying free-electron evanescent fields

    OpenAIRE

    So, J.-K.; Ou, J.-Y.; Adamo, G.; García de Abajo, F. J.; MacDonald, K. F.; Zheludev, N.I.

    2013-01-01

    We show experimentally for the first time that free-electron evanescent fields can be amplified by a plasmonic nanolayer in a manner analogous to the way in which optical fields are amplified in the poor-man's superlens.

  12. Analog circuit design designing high performance amplifiers

    CERN Document Server

    Feucht, Dennis

    2010-01-01

    The third volume Designing High Performance Amplifiers applies the concepts from the first two volumes. It is an advanced treatment of amplifier design/analysis emphasizing both wideband and precision amplification.

  13. Compact dual channel spectroscopy amplifier cum discriminator

    International Nuclear Information System (INIS)

    A single width NIM module having two channels of spectroscopy amplifier cum discriminator has been developed for Nuclear Physics experiments at IUAC. Each channel contains a shaping amplifier along with logic circuits to generate the energy and timing information respectively

  14. Single conversion stage amplifier - SICAM

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.

    2005-12-15

    This Ph.D. thesis presents a thorough analysis of the so called SICAM - SIngle Converter stage AMplifier approach to building direct energy conversion audio power amplifiers. The mainstream approach for building isolated audio power amplifiers today consists of isolated DC power supply and Class D amplifier, which essentially represents a two stage solution, where each of the components can be viewed as separate and independent part. The proposed SICAM solution strives for direct energy conversion from the mains to the audio output, by dedicating the operation of the components one to another and integrating their functions, so that the final audio power amplifier represents a single-stage topology with higher efficiency, lower volume, less board space, lower component count and subsequently lower cost. The SICAM approach is both applicable to non-isolated and isolated audio power amplifiers, but the problems encountered in these two cases are different. Non-isolated SICAM solutions are intended for both AC mains-connected and battery-powered devices. In non-isolated mains-connected SICAMs the main idea is to simplify the power supply or even provide integrated power factor correction (PFC) functions, while still maintaining low component stress and good audio performance by generally decreasing the input voltage level to the Class D audio power amplifier. On the other hand, non-isolated battery-powered SICAMs have to cope with the ever changing battery voltage and provide output voltage levels which are both lower and higher than the battery voltage, while still being simple and single-stage energy conversion solutions. In isolated SICAMs the isolation transformer adjusts the voltage level on the secondary side to the desired level, so the main challenges here are decreasing the size of the magnetic core and reducing the number and size of bulky reactive components as much as possible. The main focus of this thesis is directed towards the isolated SICAMs and

  15. European Research on THz Vacuum Amplifiers

    DEFF Research Database (Denmark)

    Brunetti, F.; Cojocarua, C.-S.; de Rossi, A.; Di Carlo, A.; Dispenza, M.; Dolfi, D.; Durand, A.; Fiorello, A.; Gohier, A.; Guiset, P.; Korantia, M.; Krozer, V.; Legagneux, P.; Marchesin, R.; Megtert, S.; Bouamrane, F.; Mineo, M.; Paoloni, C.; Pham, K.; Schnell, J.P.; Secchi, A.; Tamburri, E.; Terranova, M.L.; Ulisse, G.; Zhurbenko, Vitaliy

    The OPTHER (OPtically Driven TeraHertz AmplifiERs) project represents a considerable advancement in the field of high frequency amplification. The design and realization of a THz amplifier within this project is a consolidation of efforts at the international level from the main players of the Eu...... European research, academy and industry in vacuum electronics. This paper describes the status of the project and progress towards the THz amplifier realization....

  16. Improved charge amplifier using hybrid hysteresis compensation

    Science.gov (United States)

    Amin-Shahidi, Darya; Trumper, David L.

    2013-08-01

    We present a novel charge amplifier, with a robust feedback circuit and a method for compensating piezoelectric actuator's hysteresis at low frequencies. The amplifier uses a modified feedback circuit which improves robustness to the addition of series load impedance such as in cabling. We also describe a hybrid hysteresis compensation method for enabling the charge amplifier to reduce hysteresis at low frequencies. Experimental results demonstrate the utility of the new amplifier design.

  17. Quantum Theory of Laser Amplifiers.

    Science.gov (United States)

    Mander, Gillian Linda

    Available from UMI in association with The British Library. Requires signed TDF. We calculate the input-output characteristics of a below threshold laser amplifier. Expressions are derived for the output second- and fourth-order spectral and temporal correlation functions in terms of the corresponding input quantities, and for the photocount first and second factorial moments for both homodyne and direct detection. The general results are applied to several cases of practical interest, including specific non-classical input states. We show that a maximum of twofold amplification is permitted if squeezing in the input is to survive at the output. Similarly, for preservation of photon antibunching in amplification we show that only very small gains are allowed. The model treated here provides a detailed example of the amplifier noise limitations imposed by quantum mechanics. In particular, we show that minimum noise occurs in a cavity that is asymmetric with respect to the mirror reflectivities. The latter part of this work treats the above threshold laser amplifier. The laser output is back-scattered from a moving target to provide a weak Doppler-shifted signal which re-enters the laser cavity and is amplified. We show that the three-level atomic lasing medium is equivalent to a two-level medium pumped by an inverted bath. We use the methods of quantum statistical analysis to obtain time -evolution equations for the c-number amplitudes of the laser and signal fields. We show that the results may be applied to the below threshold regime for appropriate values of the pump parameter. By considering the amplitude differential gain we show explicitly that the behaviour of the laser around threshold is characteristic of a second -order phase transition. We calculate the output intensity gain appropriate to a heterodyne detection process, and find good agreement between the predicted gain profiles and measured data for both carbon dioxide and argon-ion lasers.

  18. Acid evaporation property in chemically amplified resists

    Science.gov (United States)

    Hashimoto, Shuichi; Itani, Toshiro; Yoshino, Hiroshi; Yamana, Mitsuharu; Samoto, Norihiko; Kasama, Kunihiko

    1997-07-01

    The lithographic performance of a chemically amplified resist system very much depends on the photo-generated acid structure. In a previous paper, we reported the molecular structure dependence of two typical photo-generated acids (aromatic sulfonic acid and alkyl sulfonic acid) from the viewpoints of lithographic performance and acid characteristics such as acid generation efficiency, acid diffusion behavior and acid evaporation property. In this paper, we evaluate the effect of the remaining solvent in a resist film on the acid evaporation property. Four types of two-component chemically amplified positive KrF resists were prepared consisting of tert-butoxycarbonyl (t-BOC) protected polyhydroxystyrene and sulfonic acid derivative photo-acid generator (PAG). Here, a different combination of two types of PAGs [2,4-dimethylbenzenesulfonic acid (aromatic sulfonic acid) derivative PAG and cyclohexanesulfonic acid (alkyl sulfonic acid) derivative PAG] and two types of solvents (propylene glycol monomethyl ether acetate; PGMEA and ethyl lactate; EL) were evaluated. The aromatic sulfonic acid was able to evaporate easily during post exposure bake (PEB) treatment, but the alkyl sulfonic acid was not. The higher evaporation property of aromatic sulfonic acid might be due to the higher vapor pressure and the longer acid diffusion length. Furthermore, the amount of aromatic sulfonic acid in the PGMEA resist was reduced by more than that in the EL resist. The amount of acid loss also became smaller at a higher prebake temperature. The concentration of the remaining solvent in the resist film decreased with the increasing prebake temperature. We think that the acid evaporation property was affected by the remaining solvent in the resist, film; the large amount of remaining solvent promoted the acid diffusion and eventually accelerated the acid evaporation from the resist film surface in the PGMEA resist. In summary, the acid evaporation property depends on both the acid

  19. Compact, harmonic multiplying gyrotron amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Guo, H.Z.; Granatstein, V.L.; Antonsen, T.M. Jr.; Levush, B.; Tate, J.; Chen, S.H. [Univ. of Maryland, College Park, MD (United States). Inst. for Plasma Research

    1995-12-31

    A compact, harmonic multiplying gyrotron traveling wave amplifier is being developed. The device is a three-stage tube with the output section running as a fourth harmonic gyro-TWT, the input section running as a fundamental gyro-TWT, and the middle operating at the second harmonic of the cyclotron frequency. Radiation is suppressed by servers between the sections. The operating beam of the tube is produced by a magnetron injection gun (MIG). A TE{sub 0n} mode selective interaction circuit consisting of mode converters and a filter waveguide is employed for both input and output sections to solve the mode competition problem, which is pervasive in gyro-TWT operation. The input section has an input coupler designed as a TE{sub 0n} mode launcher. It excites a signal at the fundamental cyclotron frequency (17.5 GHz), which is amplified in the first TWT interaction region. So far the device is similar to a two-stage harmonic gyro-TWT. The distinction is that in the three-stage device the second section will be optimized not for output power but for fourth harmonic bunching of the beam. A gyroklystron amplifier has also been designed. The configuration is similar to the gyro-TWT but with the traveling wave interaction structures replaced by mode selective special complex cavities. Cold test results of the wideband input coupler and the TE{sub 0n} mode selective interaction circuit have been obtained.

  20. European Research on THz Vacuum Amplifiers

    DEFF Research Database (Denmark)

    Brunetti, F.; Cojocarua, C.-S.; de Rossi, A.;

    2010-01-01

    The OPTHER (OPtically Driven TeraHertz AmplifiERs) project represents a considerable advancement in the field of high frequency amplification. The design and realization of a THz amplifier within this project is a consolidation of efforts at the international level from the main players of the Eu...

  1. NASA developments in solid state power amplifiers

    Science.gov (United States)

    Leonard, Regis F.

    1990-01-01

    Over the last ten years, NASA has undertaken an extensive program aimed at development of solid state power amplifiers for space applications. Historically, the program may be divided into three phases. The first efforts were carried out in support of the advanced communications technology satellite (ACTS) program, which is developing an experimental version of a Ka-band commercial communications system. These first amplifiers attempted to use hybrid technology. The second phase was still targeted at ACTS frequencies, but concentrated on monolithic implementations, while the current, third phase, is a monolithic effort that focusses on frequencies appropriate for other NASA programs and stresses amplifier efficiency. The topics covered include: (1) 20 GHz hybrid amplifiers; (2) 20 GHz monolithic MESFET power amplifiers; (3) Texas Instruments' (TI) 20 GHz variable power amplifier; (4) TI 20 GHz high power amplifier; (5) high efficiency monolithic power amplifiers; (6) GHz high efficiency variable power amplifier; (7) TI 32 GHz monolithic power amplifier performance; (8) design goals for Hughes' 32 GHz variable power amplifier; and (9) performance goals for Hughes' pseudomorphic 60 GHz power amplifier.

  2. Solid state, S-band, power amplifier

    Science.gov (United States)

    Digrindakis, M.

    1973-01-01

    The final design and specifications for a solid state, S-band, power amplifier is reported. Modifications from a previously proposed design were incorporated to improve efficiency and meet input overdrive and noise floor requirements. Reports on the system design, driver amplifier, power amplifier, and voltage and current limiter are included along with a discussion of the testing program.

  3. Solid state ku-band power amplifier

    Science.gov (United States)

    Bowers, H. C.; Lockyear, W. H.

    1972-01-01

    The design, fabrication, and testing of two types of IMPATT diode reflection amplifiers and a transmission amplifier are given. The Ku-band IMPATT diode development is discussed. Circuitry and electrical performance of the final version of the Ku-band amplifier is described. Construction details and an outline and mounting drawing are presented.

  4. low pump power photonic crystal fibre amplifiers

    DEFF Research Database (Denmark)

    Hougaard, Kristian G.; Broeng, Jes; Bjarklev, Anders Overgaard

    2003-01-01

    Designs of low pump power optical amplifiers, based on photonic crystal fibres are presented. The potential of these fibre amplifiers is investigated, and it is demonstrated that such amplifiers may deliver gains of more than 15 dB at 1550 nm with less than 1 mW of optical pump power....

  5. Design of Fragment Selector

    Directory of Open Access Journals (Sweden)

    Harbir Singh

    1981-10-01

    Full Text Available The existing manual process of weight categorization of Service shells into various standard weight groups is lengthy as well as time consuming. A method has been suggested for designing an apparatus 'Fragment Selector' which will save much labour and time in categorisation of shells.

  6. Einstein's Length Concept

    International Nuclear Information System (INIS)

    Einstein's length measuring procedure of a rod moving with velocity υ (0 ≤ |υ| < c) is discussed. The part of this procedure, namely measuring the length of the resting (υ = 0) rod, is realizable and leads to the elongation of the moving rod. The other part of Einstein's procedure, measuring the length of the moving (υ ≠ 0) rod, is not realizable and leads to the contraction of the moving rod. As the result of this procedure the moving rod contraction concept is supposed physically unfounded. (author). 8 refs; 1 fig

  7. A Characteristic Particle Length

    CERN Document Server

    Roberts, Mark D

    2015-01-01

    It is argued that there are characteristic intervals associated with any particle that can be derived without reference to the speed of light $c$. Such intervals are inferred from zeros of wavefunctions which are solutions to the Schr\\"odinger equation. The characteristic length is $\\ell=\\beta^2\\hbar^2/(8Gm^3)$, where $\\beta=3.8\\dots$; this length might lead to observational effects on objects the size of a virus.

  8. Investigation on 252Cf Fission Fragment Tracks in Polycarbonate Detectors

    Directory of Open Access Journals (Sweden)

    A. Bhattacharyya

    1992-10-01

    Full Text Available Registration and development of fission fragments emitted from /sup 252/Cf source have been carried out in three different polycarbonate detectors. The detectors have been characterised in terms of bulk etch rate and its behaviour. Maximum etchable cone lengths have been compared with the theoretically computed values. Identification of the fission fragments in terms of their mass and charge has been done with the help of the computer programme 'FFR'.

  9. NIF/LMJ prototype amplifier mechanical design

    International Nuclear Information System (INIS)

    Amplifier prototypes for the National Ignition Facility and the Laser Megajoule will be tested at Lawrence Livermore National Laboratory. The prototype amplifier, which is an ensemble of modules from LLNL and Centre d'Etudes de Limeil-Valenton, is cassette-based with bottom access for maintenance. A sealed maintenance transfer vehicle which moves optical cassettes between the amplifier and the assembly cleanroom, and a vacuum gripper which holds laser slabs during cassette assembly will also be tested. The prototype amplifier will be used to verify amplifier optical performance, thermal recovery time, and cleanliness of mechanical operations

  10. An Implantable CMOS Amplifier for Nerve Signals

    DEFF Research Database (Denmark)

    Nielsen, Jannik Hammel; Lehmann, Torsten

    In this paper, a low noise high gain CMOS amplifier for minute nerve signals is presented. The amplifier is constructed in a fully differential topology to maximize noise rejection. By using a mixture of weak- and strong inversion transistors, optimal noise suppression in the amplifier is achieved....... A continuous-time current-steering offset-compensation technique is utilized in order to minimize the noise contribution and to minimize dynamic impact on the amplifier input nodes. The method for signal recovery from noisy nerve signals is presented. A prototype amplifier is realized in a standard...

  11. Criterion of transverse coherence of self-amplified spontaneous emission in high gain free electron laser amplifiers

    International Nuclear Information System (INIS)

    In a high gain free electron laser amplifier based on Self-Amplified Spontaneous Emission (SASE) the spontaneous radiation generated by an electron beam near the undulator entrance is amplified many orders of magnitude along the undulator. The transverse coherence properties of the amplified radiation depends on both the amplification process and the coherence of the seed radiation (the undulator radiation generated in the first gain length or so). The evolution of the transverse coherence in the amplification process is studied based on the solution of the coupled Maxwell-Vlasov equations including higher order transverse modes. The coherence of the seed radiation is determined by the number of coherent modes in the phase space area of the undulator radiation. We discuss the criterion of transverse coherence and identify governing parameters over a broad range of parameters. In particular we re-examine the well known emittance criterion for the undulator radiation, which states that full transverse coherence is guaranteed if the rms emittance is smaller than the wavelength divided by 4π. It is found that this criterion is modified for SASE because of the different optimization conditions required for the electron beam. Our analysis is a generalization of the previous study by Yu and Krinsky for the case of vanishing emittance with parallel electron beam. Understanding the transverse coherence of SASE is important for the X-ray free electron laser projects now under consideration at SLAC and DESY

  12. HIGH AVERAGE POWER OPTICAL FEL AMPLIFIERS

    International Nuclear Information System (INIS)

    Historically, the first demonstration of the optical FEL was in an amplifier configuration at Stanford University [l]. There were other notable instances of amplifying a seed laser, such as the LLNL PALADIN amplifier [2] and the BNL ATF High-Gain Harmonic Generation FEL [3]. However, for the most part FELs are operated as oscillators or self amplified spontaneous emission devices. Yet, in wavelength regimes where a conventional laser seed can be used, the FEL can be used as an amplifier. One promising application is for very high average power generation, for instance FEL's with average power of 100 kW or more. The high electron beam power, high brightness and high efficiency that can be achieved with photoinjectors and superconducting Energy Recovery Linacs (ERL) combine well with the high-gain FEL amplifier to produce unprecedented average power FELs. This combination has a number of advantages. In particular, we show that for a given FEL power, an FEL amplifier can introduce lower energy spread in the beam as compared to a traditional oscillator. This properly gives the ERL based FEL amplifier a great wall-plug to optical power efficiency advantage. The optics for an amplifier is simple and compact. In addition to the general features of the high average power FEL amplifier, we will look at a 100 kW class FEL amplifier is being designed to operate on the 0.5 ampere Energy Recovery Linac which is under construction at Brookhaven National Laboratory's Collider-Accelerator Department

  13. Fragment mass analyzer project

    Energy Technology Data Exchange (ETDEWEB)

    Davids, C.N.; Back, B.B.; Blumenthal, D.J. [and others

    1995-08-01

    The FMA is now in routine operation, with about half the ATLAS experiments using the instrument. The beam time is split equally between target and focal-plane experiments. New spectroscopy-grade electronics for the FMA implantation system were acquired. This consists of 96 charge-sensitive preamps, 192 Gaussian shaping amplifier/discriminators, 96 channels of high-resolution ADCs, and 96 channels of medium resolution ADCs. This system is currently undergoing commissioning tests, and will be used in future proton radioactivity experiments.

  14. High temperature charge amplifier for geothermal applications

    Science.gov (United States)

    Lindblom, Scott C.; Maldonado, Frank J.; Henfling, Joseph A.

    2015-12-08

    An amplifier circuit in a multi-chip module includes a charge to voltage converter circuit, a voltage amplifier a low pass filter and a voltage to current converter. The charge to voltage converter receives a signal representing an electrical charge and generates a voltage signal proportional to the input signal. The voltage amplifier receives the voltage signal from the charge to voltage converter, then amplifies the voltage signal by the gain factor to output an amplified voltage signal. The lowpass filter passes low frequency components of the amplified voltage signal and attenuates frequency components greater than a cutoff frequency. The voltage to current converter receives the output signal of the lowpass filter and converts the output signal to a current output signal; wherein an amplifier circuit output is selectable between the output signal of the lowpass filter and the current output signal.

  15. Linear mode competition studies in multi-cavity gyroklystron amplifiers

    International Nuclear Information System (INIS)

    In multi-cavity gyroklystron amplifiers, the drift sections between cavities are generally designed to cutoff the mode of interest; it is the isolation between cavities that keeps the circuit from oscillating as a whole. Higher frequency modes, however, are not cutoff in the drift tubes. Because of their long effective length, these modes may have low start oscillation currents. Using the scattering matrix method, the authors find the modes in a complex, cylindrical cavity as an expansion in transverse eigenfunctions. They then compute the start oscillation current by numerically integrating the particles through the circuit. The start oscillation current determines the level of wall loading needed to suppress the mode. Results are presented for the two cavity gyroklystron amplifier to be used in an initial University of Maryland experiments. Curves of start oscillation current vs. magnetic field are shown for selected modes with azimuthal mode numbers of 0,1, and 2

  16. Recognition of an organism from fragments of its complete genome

    CERN Document Server

    Anh, V V; Yu, Z G

    2002-01-01

    This paper considers the problem of matching fragment to organism using its complete genome. Our method is based on the probability measure representation of a genome. We first demonstrate that these probability measures can be modelled as recurrent iterated function systems (RIFS) consisting of four contractive similarities. Our hypothesis is that the multifractal characteristic of the probability measure of a complete genome, as captured by the RIFS, is preserved in its reasonably long fragments. We compute the RIFS of fragments of various lengths and random starting points, and compare with that of the original sequence for recognition using the Euclidean distance. A demonstration on five randomly selected organisms supports the above hypothesis.

  17. Novel enzyme immunoassay and optimized DNA extraction for the detection of polymerase-chain-reaction-amplified viral DNA from paraffin-embedded tissue.

    Science.gov (United States)

    Merkelbach, S.; Gehlen, J.; Handt, S.; Füzesi, L.

    1997-01-01

    Four different DNA extraction methods were compared to determine their ability to provide DNA for amplification of viral sequences from paraffin-embedded human tissue samples by polymerase chain reaction (PCR). The suitability of extraction methods was assessed using parameters like DNA yield, length of recovered DNA fragments, and duration. Furthermore, the efficiency of amplifying a human single-copy gene, the beta-globin gene, from DNA samples was tested. The best preservation of DNA molecules could be achieved by binding the DNA onto a silica column before further purification. Viral DNA sequences could be amplified by PCR in DNA extracted from routinely processed paraffin blocks from cases with clinically or morphologically suspected cytomegalovirus or Epstein-Barr virus infections. The PCR products were specified by a novel liquid hybridization assay called PCR-enzyme-linked immunosorbent assay. Using this assay, the time-consuming Southern hybridization could be replaced and the time requirement for the detection of PCR products could be reduced from 1 day to 4 hours. The assay system described here represents a reliable, sensitive, and specific method for the detection of viral DNA from paraffin-embedded tissue samples. Images Figure 2 Figure 3 Figure 4 Figure 5 PMID:9137080

  18. Hot nuclei and fragmentation

    International Nuclear Information System (INIS)

    A review is made of the present status concerning the production of nuclei above 5 MeV temperature. Considerable progress has been made recently on the understanding of the formation and the fate of such hot nuclei. It appears that the nucleus seems more stable against temperature than predicted by static calculations. However, the occurrence of multifragment production at high excitation energies is now well established. The various experimental features of the fragmentation process are discussed. (author) 59 refs., 12 figs

  19. Fission fragment angular distributions

    International Nuclear Information System (INIS)

    Recently a Letter appeared (Phys. Rev. Lett., 522, 414(1984)) claiming that the usual expression for describing the angula distribution of fission fragments from compound nuclear decay is not a necessarily valid limit of a more general expression. In this comment we wish to point out that the two expressions arise from distinctly different models, and that the new expression as used in the cited reference is internally inconsistent

  20. Excited nuclei fragmentation

    International Nuclear Information System (INIS)

    Experimental indications leading to the thought of a very excited nucleus fragmentation are resumed. Theoretical approaches are briefly described; they are used to explain the phenomenon in showing off they are based on a minimum information principle. This model is based on time dependent Thomas-Fermi calculation which allows the mean field effect description, and with a site-bound percolation model which allows the fluctuation description

  1. Audio power amplifier design handbook

    CERN Document Server

    Self, Douglas

    2013-01-01

    This book is essential for audio power amplifier designers and engineers for one simple reason...it enables you as a professional to develop reliable, high-performance circuits. The Author Douglas Self covers the major issues of distortion and linearity, power supplies, overload, DC-protection and reactive loading. He also tackles unusual forms of compensation and distortion produced by capacitors and fuses. This completely updated fifth edition includes four NEW chapters including one on The XD Principle, invented by the author, and used by Cambridge Audio. Cro

  2. Cathode-follower power amplifier

    International Nuclear Information System (INIS)

    In circular accelerators and particularly in storage rings it is essential that the total impedance, as seen by the beam, be kept below some critical value. A model of the accelerating system was built using a single-ended cathode-follower amplifier driving a ferrite-loaded cavity. The system operated at 234.5 kHz with a peak output voltage of +-10 kV on the gap. The dynamic output impedance, as measured on the gap, was < 15 ohms

  3. Production and Characterization of Recombinant Light Chain and Carboxyterminal Heavy Chain Fragments of Tetanus Toxin

    OpenAIRE

    Yousefi, Mehdi; Khosravi-Eghbal, Roya; Hemmati, Azam; Shokri, Fazel

    2013-01-01

    Background Light chain (LC) and heavy chain carboxyterminal subdomain (HCC) fragments are the most important parts of tetanus neurotoxin (TeNT) which play key roles in toxicity and binding of TeNT, respectively. In the present study, these two fragments were cloned and expressed in a prokaryotic system and their identity was confirmed using anti-TeNT specific polyclonal and monoclonal antibodies. Methods LC and HCC gene segments were amplified from Clostridium tetani genomic DNA by PCR, clone...

  4. Optimal Cloning of PCR Fragments by Homologous Recombination in Escherichia coli

    OpenAIRE

    Jacobus, Ana Paula; Gross, Jeferson

    2015-01-01

    PCR fragments and linear vectors containing overlapping ends are easily assembled into a propagative plasmid by homologous recombination in Escherichia coli. Although this gap-repair cloning approach is straightforward, its existence is virtually unknown to most molecular biologists. To popularize this method, we tested critical parameters influencing the efficiency of PCR fragments cloning into PCR-amplified vectors by homologous recombination in the widely used E. coli strain DH5α. We found...

  5. Femtosecond time-resolved wave packet motion in molecular multiphoton ionization and fragmentation

    OpenAIRE

    Baumert, Thomas,; Bühler, B; Grosser, M.; Thalweiser, Rainer; Weiss, V.; Wiedenmann, Ernst; Gerber, Gustav

    1991-01-01

    The dynamics of molecular multiphoton ionization and fragmentation of a diatomic molecule (Na_2) have been studied in molecular beam experiments. Femtosecond laser pulses from an amplified colliding-pulse mode-locked (CPM) ring dye laser are employed to induce and probe the molecular transitions. The final continuum states are analyzed by photoelectron spectroscopy, by ion mass spectrometry and by measuring the kinetic energy of the formed ionic fragments. Pump-probe spectra emplo...

  6. A high-average power tapered FEL amplifier at submillimeter frequencies using sheet electron beams and short-period wigglers

    International Nuclear Information System (INIS)

    A high-average-power FEL amplifier operating at submillimeter frequencies is under development at the University of Maryland. Program goals are to produce a CW, ∼1 MW, FEL amplifier source at frequencies between 280 GHz and 560 GHz. To this end, a high-gain, high-efficiency, tapered FEL amplifier using a sheet electron beam and a short-period (superconducting) wiggler has been chosen. Development of this amplifier is progressing in three stages: (1) beam propagation through a long length (∼1 m) of short period (λω = 1 cm) wiggler, (2) demonstration of a proof-of-principle amplifier experiment at 98 GHz, and (3) designs of a superconducting tapered FEL amplifier meeting the ultimate design goal specifications. 17 refs., 1 fig., 1 tab

  7. Electroeluting DNA fragments.

    Science.gov (United States)

    Zarzosa-Alvarez, Ana L; Sandoval-Cabrera, Antonio; Torres-Huerta, Ana L; Bermudez-Cruz, Rosa M

    2010-01-01

    Purified DNA fragments are used for different purposes in Molecular Biology and they can be prepared by several procedures. Most of them require a previous electrophoresis of the DNA fragments in order to separate the band of interest. Then, this band is excised out from an agarose or acrylamide gel and purified by using either: binding and elution from glass or silica particles, DEAE-cellulose membranes, "crush and soak method", electroelution or very often expensive commercial purification kits. Thus, selecting a method will depend mostly of what is available in the laboratory. The electroelution procedure allows one to purify very clean DNA to be used in a large number of applications (sequencing, radiolabeling, enzymatic restriction, enzymatic modification, cloning etc). This procedure consists in placing DNA band-containing agarose or acrylamide slices into sample wells of the electroeluter, then applying current will make the DNA fragment to leave the agarose and thus be trapped in a cushion salt to be recovered later by ethanol precipitation. PMID:20834225

  8. High power RF solid state power amplifier system

    Science.gov (United States)

    Sims, III, William Herbert (Inventor); Chavers, Donald Gregory (Inventor); Richeson, James J. (Inventor)

    2011-01-01

    A high power, high frequency, solid state power amplifier system includes a plurality of input multiple port splitters for receiving a high-frequency input and for dividing the input into a plurality of outputs and a plurality of solid state amplifier units. Each amplifier unit includes a plurality of amplifiers, and each amplifier is individually connected to one of the outputs of multiport splitters and produces a corresponding amplified output. A plurality of multiport combiners combine the amplified outputs of the amplifiers of each of the amplifier units to a combined output. Automatic level control protection circuitry protects the amplifiers and maintains a substantial constant amplifier power output.

  9. Fragment-based lead design

    Science.gov (United States)

    Filz, O. A.; Poroikov, Vladimir V.

    2012-02-01

    State-of-the-art approaches to the fragment-based design of organic compounds with desired properties are considered. The review covers methods, which are used in different steps of the design, such as computational methods for fragment library design, experimental and computational methods for fragment discovery and methods for the generation of structures of organic compounds. Examples are given of drug candidates, which were constructed using the fragment-based approach. The bibliography includes 156 references.

  10. CONTROL OF FRAGMENTATION BY BLASTING

    OpenAIRE

    1998-01-01

    The degree of fragmentation influences the economy of the excavation operations. Characteristics of blasted rock such as fragment size, volume and mass are fundamental variables effecting the economics of a mining operation and are in effect the basis for evaluating the quality of a blast. The properties of fragmentation, such as size and shape, are very important information for the optimization of production. Three factors control the fragment size distribution: the rock structure, the q...

  11. Genotyping of bacteria belonging to the former Erwinia genus by PCR-RFLP analysis of a recA gene fragment.

    Science.gov (United States)

    Waleron, Małgorzata; Waleron, Krzysztof; Podhajska, Anna J; Lojkowska, Ewa

    2002-02-01

    Genotypic characterization, based on the analysis of restriction fragment length polymorphism of the recA gene fragment PCR product (recA PCR-RFLP), was performed on members of the former Erwinia genus. PCR primers deduced from published recA gene sequences of Erwinia carotovora allowed the amplification of an approximately 730 bp DNA fragment from each of the 19 Erwinia species tested. Amplified recA fragments were compared using RFLP analysis with four endonucleases (AluI, HinfI, TasI and Tru1I), allowing the detection of characteristic patterns of RFLP products for most of the Erwinia species. Between one and three specific RFLP groups were identified among most of the species tested (Erwinia amylovora, Erwinia ananas, Erwinia cacticida, Erwinia cypripedii, Erwinia herbicola, Erwinia mallotivora, Erwinia milletiae, Erwinia nigrifluens, Erwinia persicina, Erwinia psidii, Erwinia quercina, Erwinia rhapontici, Erwinia rubrifaciens, Erwinia salicis, Erwinia stewartii, Erwinia tracheiphila, Erwinia uredovora, Erwinia carotovora subsp. atroseptica, Erwinia carotovora subsp. betavasculorum, Erwinia carotovora subsp. odorifera and Erwinia carotovora subsp. wasabiae). However, in two cases, Erwinia chrysanthemi and Erwinia carotovora subsp. carotovora, 15 and 18 specific RFLP groups were detected, respectively. The variability of genetic patterns within these bacteria could be explained in terms of their geographic origin and/or wide host-range. The results indicated that PCR-RFLP analysis of the recA gene fragment is a useful tool for identification of species and subspecies belonging to the former Erwinia genus, as well as for differentiation of strains within E. carotovora subsp. carotovora and E. chrysanthemi. PMID:11832521

  12. Modeling Fibril Fragmentation in Real-Time

    CERN Document Server

    Tan, Pengzhen

    2012-01-01

    During the application of mass-action equation models to the study of amyloid fiber formation, time-consuming numerical calculations constitute a major bottleneck when no analytical solution is available. To conquer this difficulty, here an alternative efficient method is introduced for the fragmentation-only model. It includes two basic steps: (1) simulate close-formed time-evolution equations for the number concentration P(t) derived from the moment-closure method; (2) reconstruct the detailed fiber length distribution based on the knowledge of moments obtained in the first step. Compared to direct solution, current method speeds up the calculation by at least ten thousand times. The accuracy is also quite satastifactory if suitable forms of approximate distribution fucntion is taken. Further application to PI264-b-PFS48 micelles study performed by Guerin et al. confirms our method is very promising for the real-time analysis of the experimental data on fiber fragmentation.

  13. Heavy meson fragmentation at LHC

    Directory of Open Access Journals (Sweden)

    M. A. Gomshi Nobary

    2003-06-01

    Full Text Available   Large Hadron Collider (LHC at CERN will provide excellent opportunity to study the production and decay of heavy mesons and baryons with high statistics. We aim at the heavy mesons in this work and calculate their fragmentation functions consistent with this machine and present their total fragmentation probabilities and average fragmentation parameters.

  14. Kilowatt high-efficiency narrow-linewidth monolithic fiber amplifier operating at 1034 nm

    Science.gov (United States)

    Naderi, Nader A.; Flores, Angel; Anderson, Brian M.; Rowland, Ken; Dajani, Iyad

    2016-03-01

    Power scaling investigation of a narrow-linewidth, Ytterbium-doped all-fiber amplifier operating at 1034 nm is presented. Nonlinear stimulated Brillouin scattering (SBS) effects were suppressed through the utilization of an external phase modulation technique. Here, the power amplifier was seeded with a spectrally broadened master oscillator and the results were compared using both pseudo-random bit sequence (PRBS) and white noise source (WNS) phase modulation formats. By utilizing an optical band pass filter as well as optimizing the length of fiber used in the pre-amplifier stages, we were able to appreciably suppress unwanted amplified spontaneous emission (ASE). Notably, through PRBS phase modulation, greater than two-fold enhancement in threshold power was achieved when compared to the WNS modulated case. Consequently, by further optimizing both the power amplifier length and PRBS pattern at a clock rate of 3.5 GHz, we demonstrated 1 kilowatt of power with a slope efficiency of 81% and an overall ASE content of less than 1%. Beam quality measurements at 1 kilowatt provided near diffraction-limited operation (M2 knowledge, the power scaling results achieved in this work represent the highest power reported for a spectrally narrow all-fiber amplifier operating at < 1040 nm in Yb-doped silica-based fiber.

  15. Development of high sensitivity transimpedance amplifier module for self powered neutron detectors

    International Nuclear Information System (INIS)

    This paper describes design and development of a Transimpedance Amplifier for amplification of very low current from in core Self Powered Neutron Detectors (SPND). Measurement of neutron flux is very important for operation, control and protection of Nuclear Power Plant (NPP). SPND is used to measure Reactor incore flux/power. Based on sensitivity of emitter material used in SPND, pitch length and neutron flux (power level); the current output from SPND varies from few pA to few μA. The described amplifier is suitable to use for this current range. The amplifier provides a very high gain using a resistive T network feedback topology. The amplifier is designed in two stages using ultra low bias current FET OPAMPs. Design of Transimpedance amplifier is carefully done to include ultra low input bias current, low offset voltage and noise. The amplifier has in built test facility for calibration and on line test facility for measurement of insulation resistance (IR). The amplifier module has on board isolated DC-DC converter circuit complying MIL/STD/461C/D which generate isolated +/-15V and +12V supply to provide parameter to parameter ground isolation and independence among each module/signal.The output from the amplifier is 0V to 6V for 0 to 150%FP. The design is simulated in computer and amplifier used at TAPS-3 was modified as per new design and has been tested at TAPS-3 site. The amplifier performed satisfactorily. The results showed that the IR measurement technique adopted in the design can tolerate lower IR of SPND in existing design. (author)

  16. High-efficiency solid state power amplifier

    Science.gov (United States)

    Wallis, Robert E. (Inventor); Cheng, Sheng (Inventor)

    2005-01-01

    A high-efficiency solid state power amplifier (SSPA) for specific use in a spacecraft is provided. The SSPA has a mass of less than 850 g and includes two different X-band power amplifier sections, i.e., a lumped power amplifier with a single 11-W output and a distributed power amplifier with eight 2.75-W outputs. These two amplifier sections provide output power that is scalable from 11 to 15 watts without major design changes. Five different hybrid microcircuits, including high-efficiency Heterostructure Field Effect Transistor (HFET) amplifiers and Monolithic Microwave Integrated Circuit (MMIC) phase shifters have been developed for use within the SSPA. A highly efficient packaging approach enables the integration of a large number of hybrid circuits into the SSPA.

  17. Charm photoproduction via fragmentation

    International Nuclear Information System (INIS)

    The next-to-leading open charm production in γp collisions is calculated within the perturbative fragmentation functions formalism, to allow resummation of αslog(p2T/m2) terms. In the large pT region (pT>m) the result is consistent with the fixed order NLO calculation, small discrepancies being found for very large differ in the definition and the relative contribution of the direct and resolved terms, but essentially agree on their sum. The resummation is found to lead a reduced sensitivity to the choice of the renormalization/ factorization scale

  18. YANG-MILLS FIELD AMPLIFIER

    Directory of Open Access Journals (Sweden)

    Trunev A. P.

    2015-09-01

    Full Text Available The article presents a project of the Yang-Mills amplifier. Amplifier model is a multilayer spherical shell with increasing density towards the center. In the center of the amplifier is the core of high-density material. It is shown that in such a system, the amplitude of the Yang-Mills waves rises from the periphery to the center of several orders of magnitude. The role of the Yang-Mills field in the processes occurring in the nuclei of galaxies, stars and planets is discussed. The data modeling to strengthen the Yang-Mills field in the bowels of the planet, with an atomic explosion, and in some special devices such as the voltaic pile. To describe the mechanism of amplification chromodynamics field used as accurate results in Yang-Mills theory and numerical models developed based on an average and the exact equations as well. Among the exact solutions of the special role played by the centralsymmetric metric describing the contribution of the Yang-Mills field in the speed of recession of galaxies. Among the approximate numerical models can be noted the eight-scalar model we have developed for the simulation of non-linear color oscillations and chaos in the Yang-Mills theory. Earlier models were investigated spatio-temporal oscillations of the YangMills theory in the case of three and eight colors. The results of numerical simulation show that the nonlinear interaction does not lead to a spatial mixing of colors as it might be in the case of turbulent diffusion. Depending on the system parameters there is a suppression of the amplitude of the oscillations the first three by five colors or vice versa. The kinetic energy fluctuations or shared equally between the color components, or dominated by the kinetic energy of repressed groups of colors. In the present study, we found that amplification chromodynamic field leads to a sharp increase in the amplitude of the suppressed color, which can lead to an increase in entropy, excitation of nuclear

  19. Propagation of squeezed radiation through amplifying or absorbing random media

    CERN Document Server

    Patra, M

    2000-01-01

    We analyse how nonclassical features of squeezed radiation (in particular the sub-Poissonian noise) are degraded when it is transmitted through an amplifying or absorbing medium with randomly located scattering centra. Both the cases of direct photodetection and of homodyne detection are considered. Explicit results are obtained for the dependence of the Fano factor (the ratio of the noise power and the mean current) on the degree of squeezing of the incident state, on the length and the mean free path of the medium, the temperature, and on the absorption or amplification rate.

  20. Enhanced Gain in Photonic Crystal Amplifiers

    DEFF Research Database (Denmark)

    Ek, Sara; Semenova, Elizaveta; Hansen, Per Lunnemann;

    2012-01-01

    study of a 1 QW photonic crystal amplifier. Net gain is achieved which enables laser oscillation in photonic crystal micro cavities. The ability to freely tailor the dispersion in a semiconductor optical amplifier makes it possible to raise the optical gain considerably over a certain bandwidth. These...... results are promising for short and efficient semiconductor optical amplifiers. This effect will also benefit other devices, such as mode locked lasers....

  1. Simultaneous Measurements of Flight Times and Energies of Fission Fragments

    International Nuclear Information System (INIS)

    In a companion paper the results of measuring the prompt neutron emission from individual fission fragments arising in thermal fission are reported. In that experiment a large volume liquid scintillation counter was .used to. record the fission neutrons, and fragment mass was identified by a gold silicon surface barrier counter.- arrangement. An alternative Way of measuring the prompt neutron emission is described here. Fragment time-of- flight apparatus is mounted in an evacuated tube that passes laterally through the thermal column of the 5-MW research reactor HERALD. A centrally positioned thin source produces 3 x 105 fissions s-1. Fragments travel distances of 180 cm and 300 cm respectively to the terminal detectors, and in passing through a VYNS film, positioned 180 cm from the source along the longer flight path, eject electrons that are used to form a reference time-signal. Essentially the times of flight of both fission fragments are measured simultaneously with the kinetic energy of one of the pair. This is achieved by using a surface barrier counter for the 300-cm detector. The difficulty of maintaining good timing and energy resolutions simultaneously is overcome by routing the pulse to the charge sensitive preamplifier through a delay line amplifier from which a fast timing pulse is derived. The collected data enables the fragment mass to be determined both before and after prompt neutrons have been emitted. Hence the experiment provides a means for studying the behaviour of neutron emission from individual fragments. The experimental uncertainties are those associated with the measurement of small differences, and an appraisal is made of the errors and calibrations that enter into the measurements. Of particular importance, the response of the surface barrier counter to fission fragments is obtained directly, from the collected data from events in which the neutron emission is low. These calibrations are used in the measurements of postneutron mass

  2. Reflection amplifiers in self-regulated learning

    OpenAIRE

    Verpoorten, Dominique

    2012-01-01

    Verpoorten, D. (2012). Reflection amplifiers in self-regulated learning. Doctoral thesis. November, 9, 2012, Heerlen, The Netherlands: Open Universiteit (CELSTEC). Datawyse / Universitaire Pers Maastricht.

  3. Dynamics of Soliton Cascades in Fiber Amplifiers

    CERN Document Server

    Arteaga-Sierra, F R; Agrawal, Govind P

    2016-01-01

    We study numerically the formation of cascading solitons when femtosecond optical pulses are launched into a fiber amplifier with less energy than required to form a soliton of equal duration. As the pulse is amplified, cascaded fundamental solitons are created at different distances, without soliton fission, as each fundamental soliton moves outside the gain bandwidth through the Raman-induced spectral shifts. As a result, each input pulse creates multiple, temporally separated, ultrashort pulses of different wavelengths at the amplifier output. The number of pulses depends not only on the total gain of the amplifier but also on the width of input pulses.

  4. Ping-pong auto-zero amplifier with glitch reduction

    Science.gov (United States)

    Larson, Mark R.

    2008-01-22

    A ping-pong amplifier with reduced glitching is described. The ping-pong amplifier includes a nulling amplifier coupled to a switching network. The switching network is used to auto-zero a ping amplifier within a ping-pong amplifier. The nulling amplifier drives the output of a ping amplifier to a proper output voltage level during auto-zeroing of the ping amplifier. By being at a proper output voltage level, glitches associated with transitioning between a ping amplifier and a pong amplifier are reduced or eliminated.

  5. Linearisation of RF Power Amplifiers

    DEFF Research Database (Denmark)

    Nielsen, Per Asbeck

    2001-01-01

    linearisation systems with focus on polar modulation feedback, and a chip oriented part focusing on integrating of separate building blocks of the system on a chip. The system oriented part of this thesis deals with analog feedback linearisation systems. The Polar modulation feedback system is compared with the...... more traditional Cartesian modulation feedback system in terms of loop settlement and dependencies between the feedback signals. A method to calculate the distortion functions of the linearisation system (AM/AM and AM/PM)based on the distortion functions of the power amplifier is presented. Also the...... polar loop architecture and it’s suitability to modern digital transmitters is discussed. A proposal of an architecture that is suitable for digital transmitters, which means that it has an interface to the digital back-end, defined by low-pass signals in polar form, is presented. Simulation guidelines...

  6. Transverse pumped laser amplifier architecture

    Science.gov (United States)

    Bayramian, Andrew James; Manes, Kenneth; Deri, Robert; Erlandson, Al; Caird, John; Spaeth, Mary

    2013-07-09

    An optical gain architecture includes a pump source and a pump aperture. The architecture also includes a gain region including a gain element operable to amplify light at a laser wavelength. The gain region is characterized by a first side intersecting an optical path, a second side opposing the first side, a third side adjacent the first and second sides, and a fourth side opposing the third side. The architecture further includes a dichroic section disposed between the pump aperture and the first side of the gain region. The dichroic section is characterized by low reflectance at a pump wavelength and high reflectance at the laser wavelength. The architecture additionally includes a first cladding section proximate to the third side of the gain region and a second cladding section proximate to the fourth side of the gain region.

  7. An electron injector based on a high power X-band TWT amplifier

    International Nuclear Information System (INIS)

    Theoretical investigation of the interaction of electrons with an electromagnetic wave in a microwave amplifier indicates that nearly 50% of the electrons are in fact accelerated in the amplification process. These fast electrons are phase correlated at the output of an amplifier and they can be further accelerated. For a beam pulse of 100 nsec and an X-band amplifier, a train of about 1000 bunches can be achieved. Several schemes were considered. Here we present a uniform amplifier, a drift tube (were the slow electrons are dumped) and an accelerator section. With an initial current of 1200 A, and an input power of 20 kW we calculated electrons with energies of 6 MeV in buckets of 20 degree corresponding to about 1x1010 particles per bunch and an instantaneous current of more than 270 A; the total system length was 1.1 m

  8. Fragment oriented molecular shapes.

    Science.gov (United States)

    Hain, Ethan; Camacho, Carlos J; Koes, David Ryan

    2016-05-01

    Molecular shape is an important concept in drug design and virtual screening. Shape similarity typically uses either alignment methods, which dynamically optimize molecular poses with respect to the query molecular shape, or feature vector methods, which are computationally less demanding but less accurate. The computational cost of alignment can be reduced by pre-aligning shapes, as is done with the Volumetric-Aligned Molecular Shapes (VAMS) method. Here, we introduce and evaluate fragment oriented molecular shapes (FOMS), where shapes are aligned based on molecular fragments. FOMS enables the use of shape constraints, a novel method for precisely specifying molecular shape queries that provides the ability to perform partial shape matching and supports search algorithms that function on an interactive time scale. When evaluated using the challenging Maximum Unbiased Validation dataset, shape constraints were able to extract significantly enriched subsets of compounds for the majority of targets, and FOMS matched or exceeded the performance of both VAMS and an optimizing alignment method of shape similarity search. PMID:27085751

  9. Typing Candida Species Using Microsatellite Length Polymorphism and Multilocus Sequence Typing.

    Science.gov (United States)

    Garcia-Hermoso, Dea; Desnos-Ollivier, Marie; Bretagne, Stéphane

    2016-01-01

    To gain more insight into the epidemiological relationships between isolates of Candida spp. obtained from various origins, several molecular typing techniques have been developed. Two methods have emerged in the 2000s as soon as enough knowledge of the Candida spp. genomes was available to choose adequate loci and primers, namely microsatellite length polymorphism (MLP) and multilocus sequence typing (MLST). To contrast with previous PCR-based methods, specific amplifications with stringent conditions easily reproducible are the basis of MLP and MLST. MLST relies on Sanger sequencing to detect single-nucleotide polymorphisms within housekeeping genes. MLP needs a first in silico step to select tandemly repeated stretches of two to five nucleotides. One of the two primers used to amplify a microsatellite locus is labeled and fragment sizing is automatically performed using high-resolution electrophoresis platforms. MLST provides results easily comparable between laboratories and active MLST schemes are publicly available for the main Candida species. For comparative studies, MLP needs standards to compensate for the electrophoretic variations depending on the platforms used. Both methods can help us gain insight into the genetic relatedness of fungal isolates, both with advantages and drawbacks, and the choice of one method rather than the other depends on the task in question. PMID:26519075

  10. Intraspecific phylogeography of the gopher tortoise, Gopherus polyphemus: RFLP analysis of amplified mtDNA segments.

    Science.gov (United States)

    Osentoski, M F; Lamb, T

    1995-12-01

    The slow rate of mtDNA evolution in turtles poses a limitation on the levels of intraspecific variation detectable by conventional restriction fragment surveys. We examined mtDNA variation in the gopher tortoise (Gopherus polyphemus) using an alternative restriction assay, one in which PCR-amplified segments of the mitochondrial genome were digested with tetranucleotide-site endonucleases. Restriction fragment polymorphisms representing four amplified regions were analysed to evaluate population genetic structure among 112 tortoises throughout the species' range. Thirty-six haplotypes were identified, and three major geographical assemblages (Eastern, Western, and Mid-Florida) were resolved by UPGMA and parsimony analyses. Eastern and Western assemblages abut near the Apalachicola drainage, whereas the Mid-Florida assemblage appears restricted to the Brooksville Ridge. The Eastern/Western assemblage boundary is remarkably congruent with phylogeographic profiles for eight additional species from the south-eastern U.S., representing both freshwater and terrestrial realms. PMID:8564009

  11. Relativistic length agony continued

    Directory of Open Access Journals (Sweden)

    Redžić D.V.

    2014-01-01

    Full Text Available We made an attempt to remedy recent confusing treatments of some basic relativistic concepts and results. Following the argument presented in an earlier paper (Redžić 2008b, we discussed the misconceptions that are recurrent points in the literature devoted to teaching relativity such as: there is no change in the object in Special Relativity, illusory character of relativistic length contraction, stresses and strains induced by Lorentz contraction, and related issues. We gave several examples of the traps of everyday language that lurk in Special Relativity. To remove a possible conceptual and terminological muddle, we made a distinction between the relativistic length reduction and relativistic FitzGerald-Lorentz contraction, corresponding to a passive and an active aspect of length contraction, respectively; we pointed out that both aspects have fundamental dynamical contents. As an illustration of our considerations, we discussed briefly the Dewan-Beran-Bell spaceship paradox and the ‘pole in a barn’ paradox. [Projekat Ministarstva nauke Republike Srbije, br. 171028

  12. New concept for a regenerative amplifier for passive optical networks

    Science.gov (United States)

    Tervonen, A.; Mattila, M.; Weiershausen, W.; von Lerber, T.; Parsons, E.; Chaouch, H.; Kueppers, F.; Honkanen, S.

    2011-01-01

    Photonic balancing - a scheme where logically opposite pulses derived from the two outputs of a delay-line demodulator for phase shift keyed (PSK) signals counter-propagate in the saturated regime of a semiconductor optical amplifier (SOA) - has been proven to enhance the receiver performance, e.g. in terms of decreased optical signal-to-noise-ratio (OSNR) requirements for a given target bit error ratio (BER). Here, we extend the photonic balancing scheme towards a new concept for a regenerative amplifier targeted at extending the reach and/or the number of subscribers in passive optical networks (PON) in order to support major operators' plans to reduce the number of central offices and access areas by approximately 90%. For a given target BER, we demonstrate experimentally (a) an 8-dB higher post-amplifier loss tolerance, (b) an extended feeder line length (75 km) combined with high splitting ratio (10 layers) for a preamplified version, and (c) high input power variation tolerance (> 30 dB burst-to-burst) in upstream direction as needed for highly asymmetric tree structures.

  13. Amplified spontaneous emission and its restraint in a terawatt Ti:sapphire amplifier

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Amplified spontaneous emission (ASE) and its restraint in a femtosecond Ti: sapphire chirped_pulse amplifier were investigated. The noises arising from ASE were effectively filtered out in the spatial, temporal and spectral domain. Pulses as short as 38 fs were amplified to peak power of 1.4 TW. The power ratio between the amplified femtosecond pulse and the ASE was higher than 106:1.

  14. Distributed feedback laser amplifiers combining the functions of amplifiers and channel filters

    DEFF Research Database (Denmark)

    Wang, Z.; Durhuus, T.; Mikkelsen, Benny;

    1994-01-01

    A dynamic model for distributed feedback amplifiers, including the mode coupled equations and the carrier rate equation, is established. The presented mode coupled equations have taken into account the interaction between fast changing optical signal and the waveguide with corrugations. By showin...... the possibility of amplifying 100 ps pulses without pulse broadening, we anticipate that a distributed feedback amplifier can be used as a combined amplifier and channel filter in high bit rate transmission systems....

  15. Saturating representation of loop conformational fragments in structure databanks

    Directory of Open Access Journals (Sweden)

    Fiser András

    2006-07-01

    Full Text Available Abstract Background Short fragments of proteins are fundamental starting points in various structure prediction applications, such as in fragment based loop modeling methods but also in various full structure build-up procedures. The applicability and performance of these approaches depend on the availability of short fragments in structure databanks. Results We studied the representation of protein loop fragments up to 14 residues in length. All possible query fragments found in sequence databases (Sequence Space were clustered and cross referenced with available structural fragments in Protein Data Bank (Structure Space. We found that the expansion of PDB in the last few years resulted in a dense coverage of loop conformational fragments. For each loops of length 8 in the current Sequence Space there is at least one loop in Structure Space with 50% or higher sequence identity. By correlating sequence and structure clusters of loops we found that a 50% sequence identity generally guarantees structural similarity. These percentages of coverage at 50% sequence cutoff drop to 96, 94, 68, 53, 33 and 13% for loops of length 9, 10, 11, 12, 13, and 14, respectively. There is not a single loop in the current Sequence Space at any length up to 14 residues that is not matched with a conformational segment that shares at least 20% sequence identity. This minimum observed identity is 40% for loops of 12 residues or shorter and is as high as 50% for 10 residue or shorter loops. We also assessed the impact of rapidly growing sequence databanks on the estimated number of new loop conformations and found that while the number of sequentially unique sequence segments increased about six folds during the last five years there are almost no unique conformational segments among these up to 12 residues long fragments. Conclusion The results suggest that fragment based prediction approaches are not limited any more by the completeness of fragments in databanks but

  16. Locally Controlled Deeply Saturated Fiber Optic Parametric Amplifiers

    Science.gov (United States)

    Nissim, Ron Reuven

    A new class of highly efficient Optical Parametric Amplifiers (OPA) is explored in this dissertation, which have the potential to reduce the power requirement on the pump and enable new functionalities. This originates from the simple notion that figure of merit (FoM) of an OPA is proportional to the product of the pump power and amplifier's length and nonlinearity. Silica fibers have been developed for over five decades and offer unparalleled transparency. By merely extending the fiber, i.e. the amplifier's length, a high FoM amplifier can be formed while keeping the pump at a moderate, sub-Watt power level. Unfortunately, optical fibers are inherently non-uniform. Their core size fluctuates along the fiber on a nanometer scale which is on the order of the fiber's molecular constituents. It is currently established that the performance of a fiber-based OPA (FOPA) is dictated by its stochastic nature. In fact, given a moderate pump power level, the highly efficient OPA will be required to maintain a strict phase matching condition across hundreds of meters. Facing this challenge, this dissertation focuses on a locally-controlled, high FoM FOPA. A high FoM FOPA operates in the deeply saturated regime in which a weak signal saturates the amplifier and depletes the pump power, effectively generating an inverse response of the pump output power to the signal input power. Given FOPAs' inhomogeneous nature, the performance limit of deeply saturated FOPAs is studied. So far, FOPAs have been commonly treated as a uniform entity; however, this study discovers unique features of the system which originate from and are strongly influenced by the fiber's inhomogeneous nature. One major example is the non-reciprocal response of deeply saturated FOPAs. It was found that deeply saturated FOPAs perform very highly, as the pump can respond to a rapidly varying (sub-THz) weak (sub-muW) signal. This is a novel method which obtained orders of magnitude improvement over current

  17. Stone fragmentation by ultrasound

    Indian Academy of Sciences (India)

    S K Shrivastava; Kailash

    2004-08-01

    The presence of kidney stone in the kidney causes discomfort to patients. Hence, removal of such stones is important which is commonly done these days, non-destructively, with lithotripters without surgery. Commercially, lithotripters like extra-corporeal shock wave lithotripters (ESWL) made by Siemens etc are in routine use. These methods are very cumbersome and expensive. Treatment of the patients also takes comparatively more time because of more number of sittings. Some delicate nerves and fibres in the surrounding areas of the stones present in the kidney are also damaged by high ultrasonic intensity used in such systems. In the present work, enhancement of the kidney stone fragmentation by using ultrasound is studied. The cavitation bubbles are found to implode faster, with more disintegration efficiency of the lithotripters, which give better treatment to the patients.

  18. The Serendipity of Fragmentation

    DEFF Research Database (Denmark)

    Leixnering, Stephan; Meyer, Renate E.

    significant formal authority and an implicitly shared idea of the overall joint objectives and collective values of ‘the city‘ as a whole. To present our case, we use a twofold strategy of data collection. First, we explored publicly available sources for the architecture of the city’s organizational......Reform approaches in the public sector led to significant changes in the sector’s design. Especially NPM-inspired reform measures which had largely aimed at organizational disaggregation created pluriform landscapes of public sector organizations (PSOs). Following a core public governance principle......, it was the central government’s task to coordinate, steer and control the newly emerged decentralized organizations. This raises questions about the overall design of the public sector at present. Our paper engages with the prevalent public governance phenomenon of fragmentation from a design...

  19. Charm photoproduction via fragmentation

    International Nuclear Information System (INIS)

    The next-to-leading open charm production in γp collisions is calculated within the Perturbative Fragmentation Functions formalism, to allow resummation of αs log(pT2/m2) terms. In the large pT region (pT>m) the result is consistent with the fixed order NLO calculation, small discrepancies being found for very large pT and at the edge of phase space. The two approaches differ in the definition and the relative contribution of the direct and resolved terms, but essentially agree on their sum. The resummation is found to lead to a reduced sensitivity to the choice of the renormalization/factorization scale. (orig.)

  20. A general-purpose pulse amplifier

    International Nuclear Information System (INIS)

    In the paper proposals are made for using the technique, known from analogue computation, for transforming nuclear pulses to the shape and size desired by the means of ''operational amplifiers''. By using this technique it is possible, by means of one fundamental amplifier but with different feedback networks, to have pre-amplifiers and head-amplifiers with different pulse-handling performances and optimized with respect to the parameter of greatest interest, such as linearity, stability or overloading characteristics. As this technique involves the use of parallel-feedback it is specially suited for pre-amplifiers since most detectors are current-generators. An amplifier fulfilling the requirements necessary for use as an operational amplifier is described. The most important specifications are: 90 db gain from DC-10 kHz, then falling approximately 20 db/decade until 15 MHz (30 db gain). Four tubes are used in the amplifier. For most pulse-handling applications a stabilized power-supply is unnecessary and the stability will depend solely on the stability of the feedback network used. (author)

  1. Self-pulsation in Raman fiber amplifiers

    DEFF Research Database (Denmark)

    Pedersen, Martin Erland Vestergaard; Ott, Johan Raunkjær; Rottwitt, Karsten

    2009-01-01

    Dynamic behavior caused by Brillouin scattering in Raman fiber amplifiers is studied. Modes of self-pulsation steady state oscillations are found. Their dependence on amplification scheme is demonstrated.......Dynamic behavior caused by Brillouin scattering in Raman fiber amplifiers is studied. Modes of self-pulsation steady state oscillations are found. Their dependence on amplification scheme is demonstrated....

  2. High efficiency, low magnetic field gyroklystron amplifiers

    International Nuclear Information System (INIS)

    The possibility of operating a gyroklystron amplifier at high efficiency and low magnetic field is considered. Two devices are discussed: A two cavity second harmonic TE02 gyroklystron amplifier operating at 19.7 GHz with subharmonic bunching, and a fundamental mode TE01 gyrotwistron at 16 GHz. The nonlinear efficiency is given for both devices

  3. BROADBAND TRAVELLING WAVE SEMICONDUCTOR OPTICAL AMPLIFIER

    DEFF Research Database (Denmark)

    2010-01-01

    Broadband travelling wave semiconductor optical amplifier (100, 200, 300, 400, 800) for amplification of light, wherein the amplifier (100, 200, 300, 400, 800) comprises a waveguide region (101, 201, 301, 401, 801) for providing confinement of the light in transverse directions and adapted for...

  4. Waveguide optical amplifier for telecom applications

    OpenAIRE

    Taccheo, Stefano; Zannin, Marcelo; Ennser, Karin; Careglio, Davide; Solé Pareta, Josep; Aracil Rico, Javier

    2009-01-01

    In this paper we review progress in optical gain clamped waveguide amplifiers for applications to optical communications. We demonstrate that compact waveguide devices may offer advantages compared to standard fiber amplifiers. In particular we focus on the application of gain clamping and optical burst switching networks where physical impairments may occur due to variation of the input power. Peer Reviewed

  5. Telomere length in human liver diseases.

    Science.gov (United States)

    Urabe, Y; Nouso, K; Higashi, T; Nakatsukasa, H; Hino, N; Ashida, K; Kinugasa, N; Yoshida, K; Uematsu, S; Tsuji, T

    1996-10-01

    To determine the role of telomere-mediated gene stability in hepatocarcinogenesis, we examined the telomere length of human liver with or without chronic liver diseases and hepatocellular carcinomas (HCC). The mean telomere restriction fragment (TRF) length of normal liver (n = 13), chronic hepatitis (n = 11), liver cirrhosis (n = 24) and HCC (n = 24) was 7.8 +/- 0.2, 7.1 +/- 0.3, 6.4 +/- 0.2 and 5.2 +/- 0.2 kb, respectively (mean +/- standard error). TRF length decreased with a progression of chronic liver diseases and that in HCC was significantly shorter than that in other chronic liver diseases (p HCC to that of corresponding surrounding liver of well differentiated (n = 7), moderately differentiated (n = 10) and poorly differentiated (n = 4) HCCs were 0.83 +/- 0.06, 0.75 +/- 0.05 and 0.98 +/- 0.09, respectively. The ratio of poorly differentiated HCC was significantly higher than that of moderately differentiated HCC (p telomere length ratio of moderately differentiated HCCs revealed a decrease of the ratio with size until it reached 50 mm in diameter. In contrast, the ratio increased as the size enlarged over 50 mm. These findings suggest that the gene stability of the liver cells mediated by the telomere is reduced as chronic liver disease progresses and that telomerase is activated in poorly differentiated HCC and moderately differentiated HCC over 50 mm in diameter. PMID:8938628

  6. Fragment Identification and Statistics Method of Hypervelocity Impact SPH Simulation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaotian; JIA Guanghui; HUANG Hai

    2011-01-01

    A comprehensive treatment to the fragment identification and statistics for the smoothed particle hydrodynamics (SPH) simulation of hypervelocity impact is presented.Based on SPH method, combined with finite element method (FEM), the computation is performed.The fragments are identified by a new pre- and post-processing algorithm and then converted into a binary graph.The number of fragments and the attached SPH particles are determined by counting the quantity of connected domains on the binary graph.The size, velocity vector and mass of each fragment are calculated by the particles' summation and weighted average.The dependence of this method on finite element edge length and simulation terminal time is discussed.An example of tungsten rods impacting steel plates is given for calibration.The computation results match experiments well and demonstrate the effectiveness of this method.

  7. CONTROL OF FRAGMENTATION BY BLASTING

    Directory of Open Access Journals (Sweden)

    Branko Božić

    1998-12-01

    Full Text Available The degree of fragmentation influences the economy of the excavation operations. Characteristics of blasted rock such as fragment size, volume and mass are fundamental variables effecting the economics of a mining operation and are in effect the basis for evaluating the quality of a blast. The properties of fragmentation, such as size and shape, are very important information for the optimization of production. Three factors control the fragment size distribution: the rock structure, the quantity of explosive and its distribution within the rock mass. Over the last decade there have been considerable advances in our ability to measure and analyze blasting performance. These can now be combined with the continuing growth in computing power to develop a more effective description of rock fragmentation for use by future blasting practitioners. The paper describes a view of the fragmentation problem by blasting and the need for a new generation of engineering tools to guide the design and implementation of blasting operations.

  8. Fragmentation of suddenly heated liquids

    International Nuclear Information System (INIS)

    The rapid fragmentation of two-dimensional high-pressure disks of Lennard-Jones fluid was studied using molecular dynamics. The free expansion of 169-, 721-, 2611-, and 14 491-particle systems was studied for several sound-traversal times. The breakup into fragments (or clusters) can be roughly described by Grady's model, which balances the surface energy with the comoving (dilational) kinetic energy of the fragments. The model predicts that the number of fragments varies as the cube root of the system population and the 2D/3 power of the initial pressure where D (2 or 3) is the dimensionality of the system. The molecular-dynamics results confirm these predictions within about +- 0.1 and thereby rule out three other fragmentation models. The relatively high monomer temperatures and relatively uniform fragment temperatures found here correspond to temperatures found in recent three-dimensional Lennard-Jones simulations by Vicentini, Jacucci, and Pandharipande

  9. Fractal statistics of brittle fragmentation

    Directory of Open Access Journals (Sweden)

    M. Davydova

    2013-04-01

    Full Text Available The study of fragmentation statistics of brittle materials that includes four types of experiments is presented. Data processing of the fragmentation of glass plates under quasi-static loading and the fragmentation of quartz cylindrical rods under dynamic loading shows that the size distribution of fragments (spatial quantity is fractal and can be described by a power law. The original experimental technique allows us to measure, apart from the spatial quantity, the temporal quantity - the size of time interval between the impulses of the light reflected from the newly created surfaces. The analysis of distributions of spatial (fragment size and temporal (time interval quantities provides evidence of obeying scaling laws, which suggests the possibility of self-organized criticality in fragmentation.

  10. mm-wave solid state amplifiers

    Science.gov (United States)

    Wolfert, P. H.; Crowley, J. D.; Fank, F. B.

    The development of mm-wave amplifiers using InP Gunn diodes is reviewed including a low-noise eight-stage amplifier for replacement of a Ka-band TWTA and a three-stage amplifier for the 42.5 to 44.5 range with an output power of 100 mW and 20 dB associated gain. A detailed description of a three-stage amplifier for the 54 to 58 GHz range is given with 100 mW output power and 15 dB associated gain, a small signal gain of 30 dB and an N.F. of 15.5 to 16.5 dB. The design of a broad band, low-loss V-band circulator, which was used in the amplifier, is described.

  11. Detection of Non-Amplified Genomic DNA

    CERN Document Server

    Corradini, Roberto

    2012-01-01

    This book offers a state-of-the-art overview on non amplified DNA detection methods and provides chemists, biochemists, biotechnologists and material scientists with an introduction to these methods. In fact all these fields have dedicated resources to the problem of nucleic acid detection, each contributing with their own specific methods and concepts. This book will explain the basic principles of the different non amplified DNA detection methods available, highlighting their respective advantages and limitations. The importance of non-amplified DNA sequencing technologies will be also discussed. Non-amplified DNA detection can be achieved by adopting different techniques. Such techniques have allowed the commercialization of innovative platforms for DNA detection that are expected to break into the DNA diagnostics market. The enhanced sensitivity required for the detection of non amplified genomic DNA has prompted new strategies that can achieve ultrasensitivity by combining specific materials with specifi...

  12. Semiconductor quantum-dot lasers and amplifiers

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Borri, Paola; Ledentsov, N. N.;

    2002-01-01

    We have produced GaAs-based quantum-dot edge-emitting lasers operating at 1.16 mu m with record-low transparency current, high output power, and high internal quantum efficiencies. We have also realized GaAs-based quantum-dot lasers emitting at 1.3 mu m, both high-power edge emitters and low-power...... biased to positive net gain. We have further measured gain recovery times in quantum dot amplifiers that are significantly lower than in bulk and quantum-well semiconductor optical amplifiers. This is promising for future demonstration of quantum dot devices with high modulation bandwidth...... surface emitting VCSELs. We investigated the ultrafast dynamics of quantum-dot semiconductor optical amplifiers. The dephasing time at room temperature of the ground-state transition in semiconductor quantum dots is around 250 fs in an unbiased amplifier, decreasing to below 50 fs when the amplifier is...

  13. Radiation tolerant isolation amplifiers for temperature measurement

    International Nuclear Information System (INIS)

    This paper concentrates on the selection of radiation tolerant isolation amplifiers, which are suitable for the signal conditioners for cryogenic system in the Large Hadron Collider (LHC). The evolution and the results of different commercial isolation amplifiers' parameters under neutron and gamma radiation are presented. In most cases, the tested isolation amplifiers' input offset voltage, bias currents and output offset voltage hardly changed during the radiation. The DC gain in input stage was only affected for some isolation amplifiers with a small open loop gain. Transmission coefficient showed decrease for all the tested isolation amplifiers. Also, the DC output voltage increased and the ripple voltage decreased for all the build-in isolated regulators. In addition, results on 1B41 signal conditioner showed that it was tolerant to 7-8x1012 n/cm2, which was 50% higher than the expected dose in the LHC

  14. An Implantable CMOS Amplifier for Nerve Signals

    DEFF Research Database (Denmark)

    Nielsen, Jannik Hammel; Lehmann, Torsten

    2001-01-01

    In this paper, a low noise high gain CMOS amplifier for minute nerve signals is presented. By using a mixture of weak- and strong inversion transistors, optimal noise suppression in the amplifier is achieved. A continuous-time offset-compensation technique is utilized in order to minimize impact on...... the amplifier input nodes. The method for signal recovery from noisy nerve signals is presented. A prototype amplifier is realized in a standard digital 0.5 μm CMOS single poly, n-well process. The prototype amplifier features a gain of 80 dB over a 3.6 kHz bandwidth, a CMRR of more than 87 dB and a...

  15. Design and performance of the beamlet amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Erlandson, A.C.; Rotter, M.D.; Frank, M.D.; McCracken, R.W.

    1996-06-01

    In future laser systems, such as the National Ignition Facility (NIF), multi-segment amplifiers (MSAs) will be used to amplify the laser beam to the required levels. As a prototype of such a laser architecture, the authors have designed, built, and tested flash-lamp-pumped, Nd:Glass, Brewster-angle slab MSAs for the Beamlet project. In this article, they review the fundamentals of Nd:Glass amplifiers, describe the MSA geometry, discuss parameters that are important in amplifier design, and present our results on the characterization of the Beamlet MSAs. In particular, gain and beam steering measurements show that the Beamlet amplifiers meet all optical performance specifications and perform close to model predictions.

  16. Qubit readout with a directional parametric amplifier

    Science.gov (United States)

    Sliwa, K. M.; Abdo, B.; Narla, A.; Shankar, S.; Hatridge, M.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H.

    2014-03-01

    Josephson junction based quantum limited parametric amplifiers play an essential role in superconducting qubit measurements. These measurements necessitate circulators and isolators between the amplifier and qubit to add directionality and/or isolation. Unfortunately, this extra hardware limits both quantum measurement efficiency and experimental scalability. Here we present a quantum-limited Josephson-junction-based directional amplifier (JDA) based on a novel coupling between two nominally identical Josephson parametric converters (JPCs). The device achieves a forward gain of 11 dB with a 15 MHz dynamical bandwidth, but higher gains are possible at the expense of bandwidth. We also present measurements of a transmon qubit made with the JDA, and show minimal measurement back-action despite the absence of any isolator or circulator before the amplifier. These results provide a first step toward realizing on-chip integration of qubits and parametric amplifiers. Work supported by: IARPA, ARO, and NSF.

  17. Design of an 1800nm Raman amplifier

    DEFF Research Database (Denmark)

    Svane, Ask Sebastian; Rottwitt, Karsten

    2013-01-01

    We present the experimental results for a Raman amplifier that operates at 1810 nm and is pumped by a Raman fiber laser at 1680 nm. Both the pump laser and the Raman amplifier is polarization maintaining. A challenge when scaling Raman amplifiers to longer wavelengths is the increase in...... transmission loss, but also the reduction in the Raman gain coefficient as the amplifier wavelength is increased. Both polarization components of the Raman gain is characterized, initially for linearly co-polarized signal and pump, subsequently linearly polarized orthogonal signal and pump. The noise...... performance of the amplifier is also investigated for both configurations. Our results show an on/off gain exceeding 20 dB at 1810 nm for which the obtained effective noise figure is below 3 dB....

  18. Antibody fragments: Hope and hype

    OpenAIRE

    Nelson, Aaron L

    2010-01-01

    The antibody molecule is modular and separate domains can be extracted through biochemical or genetic means. It is clear from review of the literature that a wave of novel, antigen-specific molecular forms may soon enter clinical evaluation. This report examines the developmental histories of therapeutics derived from antigen-specific fragments of antibodies produced by recombinant processes. Three general types of fragments were observed, antigen-binding fragments (Fab), single chain variabl...

  19. Fragmentation in turbulent primordial gas

    CERN Document Server

    Glover, S C O; Klessen, R S; Bromm, V

    2010-01-01

    We report results from numerical simulations of star formation in the early universe that focus on the role of subsonic turbulence, and investigate whether it can induce fragmentation of the gas. We find that dense primordial gas is highly susceptible to fragmentation, even for rms turbulent velocity dispersions as low as 20% of the initial sound speed. The resulting fragments cover over two orders of magnitude in mass, ranging from 0.1 to 40 solar masses. However, our results suggest that the details of the fragmentation depend on the local properties of the turbulent velocity field and hence we expect considerable variations in the resulting stellar mass spectrum in different halos.

  20. Species–fragmented area relationship

    Science.gov (United States)

    Hanski, Ilkka; Zurita, Gustavo A.; Bellocq, M. Isabel; Rybicki, Joel

    2013-01-01

    The species–area relationship (SAR) gives a quantitative description of the increasing number of species in a community with increasing area of habitat. In conservation, SARs have been used to predict the number of extinctions when the area of habitat is reduced. Such predictions are most needed for landscapes rather than for individual habitat fragments, but SAR-based predictions of extinctions for landscapes with highly fragmented habitat are likely to be biased because SAR assumes contiguous habitat. In reality, habitat loss is typically accompanied by habitat fragmentation. To quantify the effect of fragmentation in addition to the effect of habitat loss on the number of species, we extend the power-law SAR to the species–fragmented area relationship. This model unites the single-species metapopulation theory with the multispecies SAR for communities. We demonstrate with a realistic simulation model and with empirical data for forest-inhabiting subtropical birds that the species–fragmented area relationship gives a far superior prediction than SAR of the number of species in fragmented landscapes. The results demonstrate that for communities of species that are not well adapted to live in fragmented landscapes, the conventional SAR underestimates the number of extinctions for landscapes in which little habitat remains and it is highly fragmented. PMID:23858440

  1. Species-fragmented area relationship.

    Science.gov (United States)

    Hanski, Ilkka; Zurita, Gustavo A; Bellocq, M Isabel; Rybicki, Joel

    2013-07-30

    The species-area relationship (SAR) gives a quantitative description of the increasing number of species in a community with increasing area of habitat. In conservation, SARs have been used to predict the number of extinctions when the area of habitat is reduced. Such predictions are most needed for landscapes rather than for individual habitat fragments, but SAR-based predictions of extinctions for landscapes with highly fragmented habitat are likely to be biased because SAR assumes contiguous habitat. In reality, habitat loss is typically accompanied by habitat fragmentation. To quantify the effect of fragmentation in addition to the effect of habitat loss on the number of species, we extend the power-law SAR to the species-fragmented area relationship. This model unites the single-species metapopulation theory with the multispecies SAR for communities. We demonstrate with a realistic simulation model and with empirical data for forest-inhabiting subtropical birds that the species-fragmented area relationship gives a far superior prediction than SAR of the number of species in fragmented landscapes. The results demonstrate that for communities of species that are not well adapted to live in fragmented landscapes, the conventional SAR underestimates the number of extinctions for landscapes in which little habitat remains and it is highly fragmented. PMID:23858440

  2. A Decidable Quantified Fragment of Set Theory Involving Ordered Pairs with Applications to Description Logics

    OpenAIRE

    Cantone, Domenico; Longo, Cristiano; Nicolosi Asmundo, Marianna

    2011-01-01

    We present a decision procedure for a quantified fragment of set theory involving ordered pairs and some operators to manipulate them. When our decision procedure is applied to formulae in this fragment whose quantifier prefixes have length bounded by a fixed constant, it runs in nondeterministic polynomial-time. Related to this fragment, we also introduce a description logic which provides an unusually large set of constructs, such as, for instance, Boolean constructs among role...

  3. Efficient double fragmentation ChIP-seq provides nucleotide resolution protein-DNA binding profiles

    NARCIS (Netherlands)

    Mokry, M.; Hatzis, P.; de Bruijn, E.; Koster, J.; Versteeg, R.; Schuijers, J.; van de Wetering, M.L.; Guryev, V.; Clevers, H.; Cuppen, E.

    2010-01-01

    Immunoprecipitated crosslinked protein-DNA fragments typically range in size from several hundred to several thousand base pairs, with a significant part of chromatin being much longer than the optimal length for next-generation sequencing (NGS) procedures. Because these larger fragments may be non-

  4. Fragment merger: an online tool to merge overlapping long sequence fragments.

    Science.gov (United States)

    Bell, Trevor G; Kramvis, Anna

    2013-03-01

    While PCR amplicons extend to a few thousand bases, the length of sequences from direct Sanger sequencing is limited to 500-800 nucleotides. Therefore, several fragments may be required to cover an amplicon, a gene or an entire genome. These fragments are typically sequenced in an overlapping fashion and assembled by manually sliding and aligning the sequences visually. This is time-consuming, repetitive and error-prone, and further complicated by circular genomes. An online tool merging two to twelve long overlapping sequence fragments was developed. Either chromatograms or FASTA files are submitted to the tool, which trims poor quality ends of chromatograms according to user-specified parameters. Fragments are assembled into a single sequence by repeatedly calling the EMBOSS merger tool in a consecutive manner. Output includes the number of trimmed nucleotides, details of each merge, and an optional alignment to a reference sequence. The final merge sequence is displayed and can be downloaded in FASTA format. All output files can be downloaded as a ZIP archive. This tool allows for easy and automated assembly of overlapping sequences and is aimed at researchers without specialist computer skills. The tool is genome- and organism-agnostic and has been developed using hepatitis B virus sequence data. PMID:23482300

  5. Fragment Merger: An Online Tool to Merge Overlapping Long Sequence Fragments

    Directory of Open Access Journals (Sweden)

    Anna Kramvis

    2013-03-01

    Full Text Available While PCR amplicons extend to a few thousand bases, the length of sequences from direct Sanger sequencing is limited to 500–800 nucleotides. Therefore, several fragments may be required to cover an amplicon, a gene or an entire genome. These fragments are typically sequenced in an overlapping fashion and assembled by manually sliding and aligning the sequences visually. This is time-consuming, repetitive and error-prone, and further complicated by circular genomes. An online tool merging two to twelve long overlapping sequence fragments was developed. Either chromatograms or FASTA files are submitted to the tool, which trims poor quality ends of chromatograms according to user-specified parameters. Fragments are assembled into a single sequence by repeatedly calling the EMBOSS merger tool in a consecutive manner. Output includes the number of trimmed nucleotides, details of each merge, and an optional alignment to a reference sequence. The final merge sequence is displayed and can be downloaded in FASTA format. All output files can be downloaded as a ZIP archive. This tool allows for easy and automated assembly of overlapping sequences and is aimed at researchers without specialist computer skills. The tool is genome- and organism-agnostic and has been developed using hepatitis B virus sequence data.

  6. Factors affecting SFHR gene correction efficiency with single-stranded DNA fragment

    International Nuclear Information System (INIS)

    A 606-nt single-stranded (ss) DNA fragment, prepared by restriction enzyme digestion of ss phagemid DNA, improves the gene correction efficiency by 12-fold as compared with a PCR fragment, which is the conventional type of fragment used in the small fragment homologous replacement method [H. Tsuchiya, H. Harashima, H. Kamiya, Increased SFHR gene correction efficiency with sense single-stranded DNA, J. Gene Med. 7 (2005) 486-493]. To reveal the characteristic features of this gene correction with the ss DNA fragment, the effects on the gene correction in CHO-K1 cells of the chain length, 5'-phosphate, adenine methylation, and transcription were studied. Moreover, the possibility that the ss DNA fragment is integrated into the target DNA was examined with a radioactively labeled ss DNA fragment. The presence of methylated adenine, but not the 5'-phosphate, enhanced the gene correction efficiency, and the optimal length of the ss DNA fragment (∼600 nt) was determined. Transcription of the target gene did not affect the gene correction efficiency. In addition, the target DNA recovered from the transfected CHO-K1 cells was radioactive. The results obtained in this study indicate that length and adenine methylation were important factors affecting the gene correction efficiency, and that the ss DNA fragment was integrated into the double-stranded target DNA

  7. Telomerase activity and telomere length in human hepatocellular carcinoma.

    Science.gov (United States)

    Huang, G T; Lee, H S; Chen, C H; Chiou, L L; Lin, Y W; Lee, C Z; Chen, D S; Sheu, J C

    1998-11-01

    Telomerase activity is activated and telomere length altered in various types of cancers, including hepatocellular carcinoma (HCC). A total of 39 HCC tissues and the corresponding non-tumour livers were analysed and correlated with clinical parameters. Telomere length was determined by terminal restriction fragment assay, and telomerase activity was assayed by telomeric repeat amplification protocol. Telomerase activity was positive in 24 of the 39 tumour tissues (1.15-285.13 total product generated (TPG) units) and in six of the 39 non-tumour liver tissues (1.05-1.73 TPG units). In the 28 cases analysed for telomere length, telomere length was shortened in 11 cases, lengthened in six cases, and unaltered in 11 cases compared with non-tumour tissues. Neither telomere length nor telomerase activity was correlated to any clinical parameters. PMID:10023320

  8. Fragmentation Considered Poisonous

    CERN Document Server

    Herzberg, Amir

    2012-01-01

    We present practical poisoning and name-server block- ing attacks on standard DNS resolvers, by off-path, spoofing adversaries. Our attacks exploit large DNS responses that cause IP fragmentation; such long re- sponses are increasingly common, mainly due to the use of DNSSEC. In common scenarios, where DNSSEC is partially or incorrectly deployed, our poisoning attacks allow 'com- plete' domain hijacking. When DNSSEC is fully de- ployed, attacker can force use of fake name server; we show exploits of this allowing off-path traffic analy- sis and covert channel. When using NSEC3 opt-out, attacker can also create fake subdomains, circumvent- ing same origin restrictions. Our attacks circumvent resolver-side defenses, e.g., port randomisation, IP ran- domisation and query randomisation. The (new) name server (NS) blocking attacks force re- solver to use specific name server. This attack allows Degradation of Service, traffic-analysis and covert chan- nel, and also facilitates DNS poisoning. We validated the attac...

  9. The CEBAF injector RF distribution and bunch-length measurement system

    International Nuclear Information System (INIS)

    The CEBAF injector includes 22 RF control modules which require an intermediate frequency (IF) of 70 MHz and a local oscillator (LO) frequency of 1427 MHz. A STAR network distributes the signals over coaxial cables that are of equal length so that all systems see the same phase drifts due to ambient temperature changes. To obtain the signal levels required by the individual RF control modules, amplifiers are used in both the LO and IF distribution. Temperature-dependent phase drifts associated with the amplifiers are minimized by a phase-lock loop around each amplifier. In addition to the frequency distribution, an automated beam bunch-length measurement is incorporated in the chopper cavities' intermediate frequency. This allows the phase of the chopper cavities to be modulated and bunch-length measurements to be performed on the electron beam downstream. (Author) 5 refs., 4 figs

  10. Fragmentation pathways of polymer ions.

    Science.gov (United States)

    Wesdemiotis, Chrys; Solak, Nilüfer; Polce, Michael J; Dabney, David E; Chaicharoen, Kittisak; Katzenmeyer, Bryan C

    2011-01-01

    Tandem mass spectrometry (MS/MS) is increasingly applied to synthetic polymers to characterize chain-end or in-chain substituents, distinguish isobaric and isomeric species, and determine macromolecular connectivities and architectures. For confident structural assignments, the fragmentation mechanisms of polymer ions must be understood, as they provide guidelines on how to deduce the desired information from the fragments observed in MS/MS spectra. This article reviews the fragmentation pathways of synthetic polymer ions that have been energized to decompose via collisionally activated dissociation (CAD), the most widely used activation method in polymer analysis. The compounds discussed encompass polystyrenes, poly(2-vinyl pyridine), polyacrylates, poly(vinyl acetate), aliphatic polyester copolymers, polyethers, and poly(dimethylsiloxane). For a number of these polymers, several substitution patterns and architectures are considered, and questions regarding the ionization agent and internal energy of the dissociating precursor ions are also addressed. Competing and consecutive dissociations are evaluated in terms of the structural insight they provide about the macromolecular structure. The fragmentation pathways of the diverse array of polymer ions examined fall into three categories, viz. (1) charge-directed fragmentations, (2) charge-remote rearrangements, and (3) charge-remote fragmentations via radical intermediates. Charge-remote processes predominate. Depending on the ionizing agent and the functional groups in the polymer, the incipient fragments arising by pathways (1)-(3) may form ion-molecule complexes that survive long enough to permit inter-fragment hydrogen atom, proton, or hydride transfers. PMID:20623599

  11. Refolding Technologies for Antibody Fragments

    OpenAIRE

    Tsutomu Arakawa; Daisuke Ejima

    2014-01-01

    Refolding is one of the production technologies for pharmaceutical grade antibody fragments. Detergents and denaturants are primarily used to solubilize the insoluble proteins. The solubilized and denatured proteins are refolded by reducing the concentration of the denaturants or detergents. Several refolding technologies have been used for antibody fragments, comprising dilution, dialysis, solid phase solvent exchange and size exclusion chromatography, as reviewed here. Aggregation suppresso...

  12. An Algebra for Program Fragments

    DEFF Research Database (Denmark)

    Kristensen, Bent Bruun; Madsen, Ole Lehrmann; Møller-Pedersen, Birger;

    1985-01-01

    Program fragments are described either by strings in the concrete syntax or by constructor applications in the abstract syntax. By defining conversions between these forms, both may be intermixed. Program fragments are constructed by terminal and nonterminal symbols from the grammar and by variab...

  13. The 60 GHz solid state power amplifier

    Science.gov (United States)

    Mcclymonds, J.

    1991-01-01

    A new amplifier architecture was developed during this contract that is superior to any other solid state approach. The amplifier produced 6 watts with 4 percent efficiency over a 2 GHz band at 61.5 GHz. The unit was 7 x 9 x 3 inches in size, 5.5 pounds in weight, and the conduction cooling through the baseplate is suitable for use in space. The amplifier used high efficiency GaAs IMPATT diodes which were mounted in 1-diode circuits, called modules. Eighteen modules were used in the design, and power combining was accomplished with a proprietary passive component called a combiner plate.

  14. Effect of Soliton Propagation in Fiber Amplifiers

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The propagation of optical solitons in fiber amplifiers is discussed by considering a model that includes linear high order dispersion, two-photon absorption, nonlinear high-order dispersion, self-induced Ramam and five-order nonlinear effects. Based on travelling wave method, the solutions of the nonlinear Schrdinger equations, and the influence on soliton propagation as well as high-order effect in the fiber amplifier are discussed in detail. It is found that because of existing five-order nonlinear effect, the solution is not of secant hyperbola type, but shows high gain state of the fiber amplifier which is very favourable to the propagation of solitons.

  15. Noise reduction in AC-coupled amplifiers

    OpenAIRE

    Serrano Finetti, Roberto Ernesto; Pallàs Areny, Ramon

    2014-01-01

    AC-coupled amplifiers are noisier than dc-coupled amplifiers because of the thermal noise of the resistor(s) in the ac-coupling network and the increased contribution of the amplifier input noise current i(n). Both contributions, however, diminish if the corner frequency f(c) of the high-pass filter observed by the signal is lowered, the cost being a longer transient response. At the same time, the presence of large resistors in the ac-coupling network suggests that the use of FET-input ampli...

  16. Fundamentals of RF and microwave transistor amplifiers

    CERN Document Server

    Bahl, Inder J

    2009-01-01

    A Comprehensive and Up-to-Date Treatment of RF and Microwave Transistor Amplifiers This book provides state-of-the-art coverage of RF and microwave transistor amplifiers, including low-noise, narrowband, broadband, linear, high-power, high-efficiency, and high-voltage. Topics covered include modeling, analysis, design, packaging, and thermal and fabrication considerations. Through a unique integration of theory and practice, readers will learn to solve amplifier-related design problems ranging from matching networks to biasing and stability. More than 240 problems are included to help read

  17. Dissection of SARS Coronavirus Spike Protein into Discrete Folded Fragments

    Institute of Scientific and Technical Information of China (English)

    LI Shuang; CAI Zhen; CHEN Yong; LIN Zhanglin

    2006-01-01

    The spike protein of the severe acute respiratory syndrome coronavirus (SARS-CoV) mediates cell fusion by binding to target cell surface receptors. This paper reports a simple method for dissecting the viral protein and for searching for foldable fragments in a random but systematic manner. The method involves digestion by DNase I to generate a pool of short DNA segments, followed by an additional step of reassembly of these segments to produce a library of DNA fragments with random ends but controllable lengths. To rapidly screen for discrete folded polypeptide fragments, the reassembled gene fragments were further cloned into a vector as N-terminal fusions to a folding reporter gene which was a variant of green fluorescent protein. Two foldable fragments were identified for the SARS-CoV spike protein, which coincide with various anti-SARS peptides derived from the hepated repeat (HR) region 2 of the spike protein. The method should be applicable to other viral proteins to isolate antigen or vaccine candidates, thus providing an alternative to the full-length proteins (subunits) or linear short peptides.

  18. Wideband 220 GHz solid state power amplifier MMIC within minimal die size

    Science.gov (United States)

    Cheron, Jerome; Grossman, Erich N.

    2014-05-01

    A wideband and compact solid state power amplifier MMIC is simulated around 220 GHz. It utilizes 6 μm emitter length common base HBTs from a 250 nm InP HBT technology. Specific power cells and power combiners are simulated in order to minimize the width of the die, which must not exceed 300 μm to avoid multimode propagation in the substrate. Four stages are implemented over a total area of the (275x1840) μm2. Simulations of this power amplifier indicate a minimum output power of 14 dBm associated with 16 dB of power gain from 213 GHz to 240 GHz.

  19. Gain performances of 980 nm-pumped erbium-doped fiber amplifiers

    Institute of Scientific and Technical Information of China (English)

    杜戈果; 陈国夫

    1999-01-01

    Through the introduction of the overlapping factors between the light (pump and signal) intensities and the erbium doping distributions inside the fiber core, analytical solutions of homogeneously broadened two-level systems for erbium-doped fiber amplifiers pumped in the 980 nm absorption band have been derived from EDFA rate equations and light propagation equations in steady-state case. By using these deduced expressions and numerical simulated methods, important features characterizing the amplifiers such as gain, pump threshold power, optimum fiber length have been analyzed and discussed.

  20. High Energy Single Frequency Resonant Amplifier Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a single frequency high energy resonant amplifier for remote sensing. Current state-of-art technologies can not provide all...

  1. Noise in phase-preserving linear amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Shashank; Jiang, Zhang; Combes, Joshua [Center for Quantum Information and Control, University of New Mexico, Albuquerque, NM 87131-0001 (United States); Caves, Carlton M. [Center for Quantum Information and Control, University of New Mexico, Albuquerque, NM 87131-0001, USA and Centre for Engineered Quantum Systems, School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072 (Australia)

    2014-12-04

    The purpose of a phase-preserving linear amplifier is to make a small signal larger, so that it can be perceived by instruments incapable of resolving the original signal, while sacrificing as little as possible in signal-to-noise. Quantum mechanics limits how well this can be done: the noise added by the amplifier, referred to the input, must be at least half a quantum at the operating frequency. This well-known quantum limit only constrains the second moments of the added noise. Here we provide the quantum constraints on the entire distribution of added noise: any phasepreserving linear amplifier is equivalent to a parametric amplifier with a physical state σ for the ancillary mode; σ determines the properties of the added noise.

  2. Noise in phase-preserving linear amplifiers

    Science.gov (United States)

    Pandey, Shashank; Jiang, Zhang; Combes, Joshua; Caves, Carlton M.

    2014-12-01

    The purpose of a phase-preserving linear amplifier is to make a small signal larger, so that it can be perceived by instruments incapable of resolving the original signal, while sacrificing as little as possible in signal-to-noise. Quantum mechanics limits how well this can be done: the noise added by the amplifier, referred to the input, must be at least half a quantum at the operating frequency. This well-known quantum limit only constrains the second moments of the added noise. Here we provide the quantum constraints on the entire distribution of added noise: any phasepreserving linear amplifier is equivalent to a parametric amplifier with a physical state σ for the ancillary mode; σ determines the properties of the added noise.

  3. Cryogenic Amplifier Based Receivers at Submillimeter Wavelengths

    Science.gov (United States)

    Chattopadhyay, Goutam; Reck, Theodore and; Schlecht, Erich; Lin, Robert; Deal, William

    2012-01-01

    The operating frequency of InP high electron mobility transistor (HEMT) based amplifiers has moved well in the submillimeter-wave frequencies over the last couple of years. Working amplifiers with usable gain in waveguide packages has been reported beyond 700 GHz. When cooled cryogenically, they have shown substantial improvement in their noise temperature. This has opened up the real possibility of cryogenic amplifier based heterodyne receivers at submillimeter wavelengths for ground-based, air-borne, and space-based instruments for astrophysics, planetary, and Earth science applications. This paper provides an overview of the science applications at submillimeter wavelengths that will benefit from this technology. It also describes the current state of the InP HEMT based cryogenic amplifier receivers at submillimeter wavelengths.

  4. Quantum cloning with an optical fiber amplifier

    OpenAIRE

    Fasel, Sylvain; Gisin, Nicolas; Ribordy, Grégoire; Scarani, Valerio; Zbinden, Hugo

    2002-01-01

    It has been shown theoretically that a light amplifier working on the physical principle of stimulated emission should achieve optimal quantum cloning of the polarization state of light. We demonstrate close-to-optimal universal quantum cloning of polarization in a standard fiber amplifier for telecom wavelengths. For cloning 1 --> 2 we find a fidelity of 0.82, the optimal value being 5/6 = 0.83.

  5. Fragmentation of Massive Protostellar Disks

    CERN Document Server

    Kratter, K M; Kratter, Kaitlin M.; Matzner, Christopher D.

    2006-01-01

    We examine whether massive-star accretion disks are likely to fragment due to self-gravity. Rapid accretion and high angular momentum push these disks toward fragmentation, whereas viscous heating and the high protostellar luminosity stabilize them. We find that for a broad range of protostar masses and for reasonable accretion times, massive disks larger than ~150 AU are prone to fragmentation. We develop an analytical estimate for the angular momentum of accreted material, extending the analysis of Matzner and Levin (2005) to account for strongly turbulent initial conditions. In a core-collapse model, we predict that disks are marginally prone to fragmentation around stars of about four to 15 solar masses -- even if we adopt conservative estimates of the disks' radii and tendency to fragment. More massive stars are progressively more likely to fragment, and there is a sharp drop in the stability of disk accretion at the very high accretion rates expected above 110 solar masses. Fragmentation may starve accr...

  6. V-band IMPATT power amplifier

    Science.gov (United States)

    Schell, S. W.

    1985-09-01

    This program is the result of the continuing demand and future requirement for a high data rate 60-GHz communications link. A reliable solid-state transmitter which delivers the necessary power over a wide bandwidth using the present IMPATT diode technology required the development of combining techniques. The development of a 60-GHz IMPATT power combiner amplifier is detailed. The results form a basis from which future wideband, high-power IMPATT amplifiers may be developed. As a result, several state-of-the-art advancements in millimeter-wave components technology were achieved. Specific achievements for the amplifier integration were: development of a nonresonant divider/combiner circuit; reproducible multiple junction circulator assemblies; and reliable high power 60-GHz IMPATT diodes. The various design approaches and tradeoffs which lead to the final amplifier configuration are discussed. A detailed circuit design is presented for the various amplifier components, and the conical line combiner, radial line combiner, and circulator development are discussed. The performance of the amplifier, the overall achievement of the program, the implications of the results, and an assessment of future development needs and recommendations are examined.

  7. Multiple excitation regenerative amplifier inertial confinement system

    International Nuclear Information System (INIS)

    The invention relates to apparatus and methods for producing high intensity laser radiation generation which is achieved through an optical amplifier-storage ring design. One or two synchronized, counterpropagating laser pulses are injected into a regenerative amplifier cavity and amplified by gain media which are pumped repetitively by electrical or optical means. The gain media excitation pulses are tailored to efficiently amplify the laser pulses during each transit. After the laser pulses have been amplified to the desired intensity level, they are either switched out of the cavity by some switch means, as for example an electro-optical device, for any well known laser end uses, or a target means may be injected into the regenerative amplifier cavity in such a way as to intercept simultaneously the counterpropagating laser pulses. One such well known end uses to which this invention is intended is for production of high density and temperature plasmas suitable for generating neutrons, ions and x-rays and for studying matter heated by high intensity laser radiation

  8. An improved AC-amplifier for electrophysiology

    Directory of Open Access Journals (Sweden)

    Jorgovanović Nikola

    2009-01-01

    Full Text Available We present the design, simulation and test results of a new AC amplifier for electrophysiological measurements based on a three op-amp instrumentation amplifier (IA. The design target was to increase the common mode rejection ratio (CMRR, thereby improving the quality of the recorded physiological signals in a noisy environment. The new amplifier actively suppresses the DC component of the differential signal and actively reduces the common mode signal in the first stage of the IA. These functions increase the dynamic range of the amplifier's first stage of the differential signal. The next step was the realization of the amplifier in a single chip technology. The design and tests of the new AC amplifier with a differential gain of 79.2 dB, a CMRR of 130 dB at 50 Hz, a high-pass cutoff frequency at 0.01 Hz and common mode reduction in the first stage of the 49.8 dB are presented in this paper.

  9. Heavy quark fragmenting jet functions

    International Nuclear Information System (INIS)

    Heavy quark fragmenting jet functions describe the fragmentation of a parton into a jet containing a heavy quark, carrying a fraction of the jet momentum. They are two-scale objects, sensitive to the heavy quark mass, mQ, and to a jet resolution variable, τN. We discuss how cross sections for heavy flavor production at high transverse momentum can be expressed in terms of heavy quark fragmenting jet functions, and how the properties of these functions can be used to achieve a simultaneous resummation of logarithms of the jet resolution variable, and logarithms of the quark mass. We calculate the heavy quark fragmenting jet function GQQ at O(αs), and the gluon and light quark fragmenting jet functions into a heavy quark, GgQ and GlQ, at O(αs2). We verify that, in the limit in which the jet invariant mass is much larger than mQ, the logarithmic dependence of the fragmenting jet functions on the quark mass is reproduced by the heavy quark fragmentation functions. The fragmenting jet functions can thus be written as convolutions of the fragmentation functions with the matching coefficients Jij, which depend only on dynamics at the jet scale. We reproduce the known matching coefficients Jij at O(αs), and we obtain the expressions of the coefficients JgQ and JlQ at O(αs2). Our calculation provides all the perturbative ingredients for the simultaneous resummation of logarithms of mQ and τN

  10. Observation of high seasonal variation in community structure of denitrifying bacteria in arable soil receiving artificial fertilizer and cattle manure by determining T-RFLP of nir gene fragments

    DEFF Research Database (Denmark)

    Priemé, Anders; Wolsing, Martin

    2004-01-01

    Temporal and spatial variation of communities of soil denitrifying bacteria at sites receiving mineral fertilizer (60 and 120 kg N ha-1 year-1) and cattle manure (75 and 150 kg N ha-1 year-1) were explored using terminal restriction fragment length polymorphism (T-RFLP) analyses of PCR amplified...... significant seasonal shift in the community structure of nirK-containing bacteria. Also, sites treated with mineral fertilizer or cattle manure showed different communities of nirK-containing denitrifying bacteria, since the T-RFLP patterns of soils treated with these fertilizers were significantly different...... investigated belonged to a yet uncultivated cluster of denitrifying bacteria....

  11. Velocity fluctuations of fission fragments

    CERN Document Server

    Llanes-Estrada, Felipe J; Martinez, Jose L Muñoz

    2015-01-01

    We propose event by event velocity fluctuations of nuclear fission fragments as an additional interesting observable that gives access to the nuclear temperature in an independent way from spectral measurements and relates the diffusion and friction coefficients for the relative fragment coordinate in Kramer-like models (in which some aspects of fission can be understood as the diffusion of a collective variable through a potential barrier). We point out that neutron emission by the heavy fragments can be treated in effective theory if corrections to the velocity distribution are needed.

  12. Velocity fluctuations of fission fragments

    Science.gov (United States)

    Llanes-Estrada, Felipe J.; Carmona, Belén Martínez; Martínez, Jose L. Muñoz

    2016-02-01

    We propose event by event velocity fluctuations of nuclear fission fragments as an additional interesting observable that gives access to the nuclear temperature in an independent way from spectral measurements and relates the diffusion and friction coefficients for the relative fragment coordinate in Kramers-like models (in which some aspects of fission can be understood as the diffusion of a collective variable through a potential barrier). We point out that neutron emission by the heavy fragments can be treated in effective theory if corrections to the velocity distribution are needed.

  13. The spectroscopy of fission fragments

    International Nuclear Information System (INIS)

    High-resolution measurements on γ rays from fission fragments have provided a rich source of information, unobtainable at the moment in any other way, on the spectroscopy of neutron-rich nuclei. In recent years important data have been obtained on the yrast- and near yrast-structure of neutron-rich fission fragments. We discuss the scope of measurements which can be made on prompt gamma rays from secondary fission fragments, the techniques used in the experiments and some results recently obtained. (author)

  14. A model for projectile fragmentation

    International Nuclear Information System (INIS)

    A model for projectile fragmentation is developed whose origin can be traced back to the Bevalac era. The model positions itself between the phenomenological EPAX parametrization and transport models like 'Heavy Ion Phase Space Exploration' (HIPSE) model and antisymmetrised molecular dynamics (AMD) model. A very simple impact parameter dependence of input temperature is incorporated in the model which helps to analyze the more peripheral collisions. The model is applied to calculate the charge, isotopic distributions, average number of intermediate mass fragments and the average size of largest cluster at different Zbound of different projectile fragmentation reactions at different energies.

  15. Fragmentation Function in Thermofield Dynamics

    Science.gov (United States)

    Ladrem, M.; Chekerker, M.; Khanna, F. C.; Santana, A. E.

    2013-04-01

    The fragmentation function at high energy experiments is introduced by using thermofield dynamics (TFD), a real-time finite-temperature quantum field formalism. Due to the structure of TFD, the results at T = 0 and T ≠ 0 are split in a direct way. As an application, we consider the temperature effect on the fragmentation function of a hadron leading to quark-antiquark pairs. Using a definition of Wilson-loop in real-time, we find that the fragmentation function decreases in magnitude with an increase in the temperature.

  16. A model for projectile fragmentation

    CERN Document Server

    Chaudhuri, G; Gupta, S Das

    2012-01-01

    A model for projectile fragmentation is developed whose origin can be traced back to the Bevalac era. The model positions itself between the phenomenological EPAX parametrization and microscopic transport models like "Heavy Ion Phase Space Exploration" (HIPSE) model and antisymmetrised molecular dynamics (AMD) model. A very simple impact parameter dependence of input temperature is incorporated in the model which helps to analyze the more peripheral collisions. The model is applied to calculate the charge, isotopic distributions, average number of intermediate mass fragments and the average size of largest cluster at different $Z_{bound}$ of different projectile fragmentation reactions at different energies.

  17. The spectroscopy of fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, W.R. [Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL (United Kingdom); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    High-resolution measurements on {gamma} rays from fission fragments have provided a rich source of information, unobtainable at the moment in any other way, on the spectroscopy of neutron-rich nuclei. In recent years important data have been obtained on the yrast- and near yrast-structure of neutron-rich fission fragments. We discuss the scope of measurements which can be made on prompt gamma rays from secondary fission fragments, the techniques used in the experiments and some results recently obtained. (author) 24 refs., 8 figs., 1 tab.

  18. A functional fragment of Tau forms fibers without the need for an intermolecular cysteine bridge

    Energy Technology Data Exchange (ETDEWEB)

    Huvent, Isabelle; Kamah, Amina; Cantrelle, François-Xavier [CNRS UMR 8576, University of Lille1, 59655 Villeneuve d’Ascq (France); Barois, Nicolas [Plate-forme BICeL-IFR142, Institut Pasteur de Lille, Lille (France); Slomianny, Christian [Inserm U1003, Laboratoire de physiologie cellulaire, Université Lille 1, 59650 Villeneuve d’Ascq (France); Smet-Nocca, Caroline; Landrieu, Isabelle [CNRS UMR 8576, University of Lille1, 59655 Villeneuve d’Ascq (France); Lippens, Guy, E-mail: Guy.Lippens@univ-lille1.fr [CNRS UMR 8576, University of Lille1, 59655 Villeneuve d’Ascq (France)

    2014-03-07

    Highlights: • A functional fragment of Tau forms bundled ribbon-like fibrils. • Nucleation of its fibril formation is faster than for full-length Tau. • In contrast to full-length Tau, without cysteines, the fragment still forms fibers. - Abstract: We study the aggregation of a fragment of the neuronal protein Tau that contains part of the proline rich domain and of the microtubule binding repeats. When incubated at 37 °C with heparin, the fragment readily forms fibers as witnessed by Thioflavin T fluorescence. Electron microscopy and NMR spectroscopy show bundled ribbon like structures with most residues rigidly incorporated in the fibril. Without its cysteines, this fragment still forms fibers of a similar morphology, but with lesser Thioflavin T binding sites and more mobility for the C-terminal residues.

  19. Specific Detection of Peronospora tabacina by PCR-amplified rDNA Sequences

    OpenAIRE

    Jwu-Guh Tsay; Chishih Chu; Ya-Han Chuang; Ruey-Shyang Chen

    2006-01-01

    Peronospora tabacina Adam, a downy mildew fungus, is a devastating disease of tobacco and a pathogen of import prohibition in Taiwan. For quarantine purpose, we developed a nested PCR method to detect this pathogen. With universal primer pair ITS1/ITS4, internal transcribed spacer (ITS) region of pathogen`s rDNA was amplified. Specific PCR primers (PT1/PT2) were designed based on ITS sequence and used to amplify a 493-bp rDNA fragments from P. tabacina. In order to increase the sensitivity, a...

  20. Transmission, reflection and localization of waves in one-dimensional amplifying media with nonlinear gain

    Science.gov (United States)

    Nguyen, Ba Phi; Kim, Kihong

    2014-06-01

    We study theoretically the influence of nonlinear gain effects on the transmission and the Anderson localization of waves in both uniform and random one-dimensional amplifying media by using the discrete nonlinear Schrödinger equation. In uniform amplifying media with nonlinear gain, we find that the strong oscillatory behavior of the transmittance and the reflectance for odd and even values of the sample length disappears for large nonlinearities. The exponential decay rate of the transmittance in the asymptotic limit is found to be independent of nonlinear gain. In random amplifying media, we find that the maximum values of the disorder-averaged logarithmic transmittance and reflectance depend nonmonotonically on the strength of nonlinear gain. We also find that the localization length is independent of nonlinear gain. In other words, the Anderson localization is neither enhanced nor weakened due to nonlinear gain. In both the uniform and the random cases, the crossover length, which is the critical length for the amplification to be efficient, is strongly reduced by the nonlinear nature of the gain.

  1. The dynamics of fragment formation

    International Nuclear Information System (INIS)

    We demonstrate that in the Quantum Molecular Dynamics model, dynamical correlations can result in the production rate for final state nucleon clusters (and hence composite fragments) being higher than would be expected if statistics and the available phase space were dominant in determining composite formation. An intranuclear cascade or a Boltzmann-Uehling-Uhlenbeck model, combined with a statistical approach in the late stage of the collision to determine composites, provides an equivalent description only under limited conditions of centrality and beam energy. We use data on participant fragment production in Au + Au collisions in the Bevalac's BOS time projection chamber to map out the parameter space where statistical clustering provides a good description. In particular, we investigate momentum-space densities of fragments up to 4He as a function of fragment transverse momentum, azimuth relative to the reaction plane, rapidity, multiplicity and beam energy

  2. Fragmentation of Neutron Star Matter

    CERN Document Server

    Alcain, P N

    2016-01-01

    Background: Neutron stars are astronomical systems with nucleons submitted to extreme conditions. Due to the long range coulomb repulsion between protons, the system has structural inhomogeneities. These structural inhomogeneities arise also in expanding systems, where the fragment distribution is highly dependent on the thermodynamic conditions (temperature, proton fraction, ...) and the expansion velocity. Purpose: We aim to find the different regimes of fragment distribution, and the existence of infinite clusters. Method: We study the dynamics of the nucleons with a semiclassical molecular dynamics model. Starting with an equilibrium configuration, we expand the system homogeneously until we arrive to an asymptotic configuration (i. e. very low final densities). We study the fragment distribution throughout this expansion. Results: We found the typical regimes of the asymptotic fragment distribution of an expansion: u-shaped, power law and exponential. Another key feature in our calculations is that, sinc...

  3. Medium Power 352 MHZ solid state pulsed RF amplifiers for the CERN LINAC4 Project

    CERN Document Server

    Broere, J; Gómez Martínez, Y; Rossi, M

    2011-01-01

    Economic, modular and highly linear pulsed RF amplifiers have recently been developed to be used for the three buncher cavities in the CERN Linac4. The amplifiers are water-cooled and can provide up to 33 kW pulsed RF Power, 1.5 ms pulse length and 50 Hz repetition rate. Furthermore a 60 kW unit is under construction to provide the required RF Power for the debuncher cavity. The concept is based on 1.2 kW RF power modules using the latest 6th generation LDMOS technology. For integration into the CERN control environment the amplifiers have an internal industrial controller, which will provide easy control and extended diagnostic functions. This paper describes the construction, performance, including linearity, phase stability and EMC compliance tests

  4. Generation of ultrashort radiation pulses by injection locking a regenerative free-electron-laser amplifier

    International Nuclear Information System (INIS)

    We demonstrate how a steady-state train of ultrashort radiation pulses can be produced utilizing a new free-electron laser (FEL) configuration, the injection-locked regenerative klystron amplifier (IRKA). This configuration consists of two elements: (1) a prebuncher, which microbunches the electron beams at the desired output wavelength, and (2) a multipass FEL operated at a very small cavity desynchronism and below the lasing threshold, in the regime of regenerative amplification. The regenerative amplifier is driven by the microbunched electron beam, so that the pulse-to-pulse stability is provided by the pre-buncher. The broad amplification bandwidth of this regenerative amplifier enables generation of ultrashort pulses, much shorter than a slippage length, with high efficiency. The IRKA configuration can produce such ultra-short radiation pulses while avoiding the chaotic dynamics that limits conventional FEL performance. copyright 1997 The American Physical Society

  5. Velocity fluctuations of fission fragment.

    OpenAIRE

    Llanes Estrada, Felipe José; Martínez Carmona, Belén; Muñoz Martínez, José L.

    2016-01-01

    We propose event by event velocity fluctuations of nuclear fission fragments as an additional interesting observable that gives access to the nuclear temperature in an independent way from spectral measurements and relates the diffusion and friction coefficients for the relative fragment coordinate in Kramers-like models (in which some aspects of fission can be understood as the diffusion of a collective variable through a potential barrier). We point out that neutron emission by the heavy fr...

  6. Laser spectroscopy of fission fragments

    International Nuclear Information System (INIS)

    The study of the nuclear structure of fission fragments is discussed. They are neutron-rich nuclei the structure of which possesses some peculiarities. Two regions of fission fragments are discussed: near the shell closures N = 50 and N = 82 and at the boundary of the deformation. A view on the optical properties of these elements is presented and different laser spectroscopic methods for their investigation are proposed. (author)

  7. [Telomere length and telomerase activity in hepatocellular carcinoma].

    Science.gov (United States)

    Nakashio, R; Kitamoto, M; Nakanishi, T; Takaishi, H; Takahashi, S; Kajiyama, G

    1998-05-01

    Telomerase activity and terminal restriction fragment (TRF) length were examined in hepatocellular carcinoma (HCC). Telomerase activity was assayed by telomeric repeat amplification protocol (TRAP) connected with an internal telomerase assay standard (ITAS). The incidence of strong telomerase activity (highly variable level compared with the activity of non-cancerous liver tissue) was 79% in well, 84% in moderately, and 100% in poorly differentiated HCC, while 0% in non-cancerous liver tissues. The incidence of TRF length alteration (reduction or elongation) was 53% in HCC. The incidence of TRF alteration was significantly higher in HCC exceeding 3 cm in diameter, moderately or poorly differentiated in histology. Telomerase activity was not associated with TRF length alteration in HCC. In conclusion, strong telomerase activity and TRF length alteration increased with HCC tumor progressions. PMID:9613130

  8. Population inversion in fluorescing fragments of super-excited molecules inside an air filament

    International Nuclear Information System (INIS)

    An original idea is reviewed. When a molecule is pumped into a super-excited state, one of its decay channels is neutral dissociation. One or more of the neutral fragments will fluoresce. Hence, if a lower state of such fluorescing fragments was populated through other channels but with a lower probability, population inversion of the fluorescing fragments would be naturally realized. This idea seems to be validated, so far, by comparing published work on three hydrocarbon molecules, CH4, C2H2, C2H4, and water vapor, H2O. After super-excitation in a femtosecond laser filament in air mixed with these molecules, the fluorescence from the CH or OH fragments exhibits population inversion, i.e., amplified spontaneous emission was observed in the backscattering direction of the filament. (paper)

  9. Isolator fragmentation and explosive initiation tests

    Energy Technology Data Exchange (ETDEWEB)

    Dickson, Peter [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Rae, Philip John [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Foley, Timothy J. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Novak, Alan M. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Armstrong, Christopher Lee [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Baca, Eva V. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Gunderson, Jake Alfred [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

    2015-09-30

    Three tests were conducted to evaluate the effects of firing an isolator in proximity to a barrier or explosive charge. The tests with explosive were conducted without barrier, on the basis that since any barrier will reduce the shock transmitted to the explosive, bare explosive represents the worst-case from an inadvertent initiation perspective. No reaction was observed. The shock caused by the impact of a representative plastic material on both bare and cased PBX9501 is calculated in the worst-case, 1-D limit, and the known shock response of the HE is used to estimate minimum run-to-detonation lengths. The estimates demonstrate that even 1-D impacts would not be of concern and that, accordingly, the divergent shocks due to isolator fragment impact are of no concern as initiating stimuli.

  10. Regime for a Self-ionizing Raman Laser Amplifier

    International Nuclear Information System (INIS)

    Backward Raman amplification and compression at high power might occur if a long pumping laser pulse is passed through a plasma to interact resonantly with a counter-propagating short seed pulse [V.M. Malkin, et al., Phys. Rev. Lett. 82 (1999) 4448-4451]. One critical issue, however, is that the pump may be unacceptably depleted due to spontaneous Raman backscatter from intrinsic fluctuations in the amplifying plasma medium prior to its useful interaction with the seed. Premature backscatter may be avoided, however, by employing a gaseous medium with pump intensities too low to ionize the medium, and using the intense seed to produce the plasma by rapid photoionization as it is being amplified [V.M. Malkin, et al., Phys. Plasmas (2001)]. In addition to allowing that only rather low power pumps be used, photoionization introduces a damping of the short pulse which must be overcome by the Raman growth rate for net amplification to occur. The parameter space of gas densities, laser wavelengths, and laser intensities is surveyed to identify favorable regimes for this effect. Output laser intensities of 10(superscript ''17'') W/cm(superscript ''2'') for 0.5 mm radiation are found to be feasible for such a scheme using a pump of 10(superscript ''13'') W/cm(superscript ''2'') and an initial seed of 5 x 10(superscript ''14'') W/cm(superscript ''2'') over an amplification length of 5.6 cm in hydrogen gas

  11. Regime for a self-ionizing Raman laser amplifier

    International Nuclear Information System (INIS)

    Backward Raman amplification and compression at high power might occur if a long pumping laser pulse is passed through a plasma to interact resonantly with a counter-propagating short seed pulse [V. M. Malkin et al., Phys. Rev. Lett. 82, 4448-4451 (1999)]. One critical issue, however, is that the pump may be unacceptably depleted due to spontaneous Raman backscatter from intrinsic fluctuations in the amplifying plasma medium prior to its useful interaction with the seed. Premature backscatter may be avoided, however, by employing a gaseous medium with pump intensities too low to ionize the medium and using the intense seed to produce the plasma by rapid photoionization as it is being amplified [V. M. Malkin et al., Phys. Plasmas 8, 4698-4699 (2001)]. In addition to allowing that only rather low power pumps be used, photoionization introduces a damping of the short pulse which must be overcome by the Raman growth rate for net amplification to occur. The parameter space of gas densities, laser wavelengths, and laser intensities is surveyed to identify favorable regimes for this effect. Output laser intensities of 2x1017 W/cm2 for 0.5 μm radiation are found to be feasible for such a scheme using a pump of 1x1013 W/cm2 and an initial seed of 5x1014 W/cm2 over an amplification length of 5.6 cm in hydrogen gas

  12. Spheromak reactor with poloidal flux-amplifying transformer

    Science.gov (United States)

    Furth, Harold P.; Janos, Alan C.; Uyama, Tadao; Yamada, Masaaki

    1987-01-01

    An inductive transformer in the form of a solenoidal coils aligned along the major axis of a flux core induces poloidal flux along the flux core's axis. The current in the solenoidal coil is then reversed resulting in a poloidal flux swing and the conversion of a portion of the poloidal flux to a toroidal flux in generating a spheromak plasma wherein equilibrium approaches a force-free, minimum Taylor state during plasma formation, independent of the initial conditions or details of the formation. The spheromak plasma is sustained with the Taylor state maintained by oscillating the currents in the poloidal and toroidal field coils within the plasma-forming flux core. The poloidal flux transformer may be used either as an amplifier stage in a moving plasma reactor scenario for initial production of a spheromak plasma or as a method for sustaining a stationary plasma and further heating it. The solenoidal coil embodiment of the poloidal flux transformer can alternately be used in combination with a center conductive cylinder aligned along the length and outside of the solenoidal coil. This poloidal flux-amplifying inductive transformer approach allows for a relaxation of demanding current carrying requirements on the spheromak reactor's flux core, reduces plasma contamination arising from high voltage electrode discharge, and improves the efficiency of poloidal flux injection.

  13. The OPTHER Project: Progress toward the THz Amplifier

    DEFF Research Database (Denmark)

    Paoloni, C; Brunetti, F; Di Carlo, A;

    2011-01-01

    This paper describes the status of the OPTHER (OPtically driven TeraHertz AmplifiERs) project and progress toward the THz amplifier realization. This project represents a considerable advancement in the field of high frequency amplification. The design and realization of a THz amplifier within th...

  14. Estimation of gestational age from gall-bladder length.

    Science.gov (United States)

    Udaykumar, K; Udaykumar, Padmaja; Nagesh, K R

    2016-01-01

    Establishing a precise duration of gestation is vital in situations such as infanticide and criminal abortions. The present study attempted to estimate the gestational age of the foetus from gall-bladder length. Foetuses of various gestational age groups were dissected, and the length of the gall bladder was measured. The results were analysed, and a substantial degree of correlation was statistically confirmed. This novel method is helpful when the foetus is fragmented, putrefied or eviscerated, where this method can be used as an additional parameter to improve the accuracy of foetal age estimation. PMID:25990829

  15. A modification to the SCAR (Sequence Characterized Amplified Region method provides phylogenetic insights within Ceratozamia (Zamiaceae Una modificación al método SCAR (Sequence Characterized Amplified Region aporta entendimiento filogenético en Ceratozamia (Zamiaceae

    Directory of Open Access Journals (Sweden)

    Dolores González

    2012-12-01

    Full Text Available Phylogenetic relationships among closely related plant species are still problematic. DNA intergenic regions often are insufficiently variable to provide desired resolution or support. In this study, a modification to the Sequence Characterized Amplified Region (SCAR method was used to find polymorphic loci for phylogenetic analyses within Ceratozamia. RAPD markers were first used to detect variation in 5 species. Then, equal length fragments found in 2 or more species were excised from the gel, purified and digested with frequent cutter restriction enzymes for isolating both ends, which have the same primer site. Digested fragments were sequenced with the RAPD primer. Variable sequences were used to design specific primers for amplifying and sequencing in all species for phylogenetic analyses. Our results confirmed the previously known high genome sequence resemblance within this genus that contrasts with its high morphological variation. Only 7 parsimony informative characters were found with this approach. Nonetheless, the Digested-SCAR (D-SCAR method provided some phylogenetic insights. Four main clades consistent with distribution ranges of the species were detected. The approach presented here was effective to solve some relationships within the genus and can potentially be implemented in other organisms to find polymorphic loci for phylogenetic studies at any taxonomic level.Las relaciones filogenéticas entre especies de plantas cercanamente relacionadas es aún problemático. Las regiones intergénicas del ADN son a menudo insuficientemente variables para proveer los niveles de resolución y soporte deseados. En este estudio, se usó una modificación al método Sequence Characterized Amplified Region (SCAR para encontrar loci polimórficos para análisis filogenéticos en Ceratozamia. Primero se usaron marcadores RAPD para detectar variación en 5 especies; luego, se cortaron del gel los fragmentos de la misma longitud en 2 o m

  16. Computer-aided design of broad band reflection type amplifiers

    DEFF Research Database (Denmark)

    Hammershaimb, Edgar; Jeppesen, Palle; Schjær-Jacobsen, Hans

    1974-01-01

    Microwave negative resistance reflection type amplifiers using stable transferred electron devices (TED's) are optimized by numerical optimization techniques programmed for an interactive graphic datascreen. The small signal impedance of packaged TED's is measured on an automatic network analyzer....... At the same time the impedance of unpackaged devices are obtained by on-line correction for the package parasitics. The microwave circuit chosen is a multiple slug coaxial cavity, that is modelled by sections of lossy transmission lines including step susceptances. The measured small signal impedance...... of the packaged TED's and the cavity model are used in a direct optimization procedure, in which the calculated minimum gain in the prescribed frequency range is progressively maximized by adjusting the lengths, characteristic impedances and positions of the slugs. The computed results are displayed...

  17. Amplifier Noise Based Optical Steganography with Coherent Detection

    Science.gov (United States)

    Wu, Ben; Chang, Matthew P.; Caldwell, Naomi R.; Caldwell, Myles E.; Prucnal, Paul R.

    2014-12-01

    We summarize the principle and experimental setup of optical steganography based on amplified spontaneous emission (ASE) noise. Using ASE noise as the signal carrier, optical steganography effectively hides a stealth channel in both the time domain and the frequency domain. Coherent detection is used at the receiver of the stealth channel. Because ASE noise has short coherence length and random phase, it only interferes with itself within a very short range. Coherent detection requires the stealth transmitter and stealth receiver to precisely match the optical delay,which generates a large key space for the stealth channel. Several methods to further improve optical steganography, signal to noise ratio, compatibility with the public channel, and applications of the stealth channel are also summarized in this review paper.

  18. Pulsed ti: sapphire laser power amplifier

    International Nuclear Information System (INIS)

    We have demonstrated an all solid state Ti:Sapphire laser system consisting of a power oscillator and single pass amplifier. The electrical-to-optical efficiency far exceeds that of the current CW systems. The pump lasers have lower capital and operating costs than the Argon-ion laser. In the future, we plan to scale the output power to higher levels by adding a fourth pump laser and improving the output power of the current pump lasers. Modeling results suggest that a large increase in efficiency can be realized by improving the beam quality of the pump lasers, even at the cost of reduced output power. We will explore this option by adding apertures to the cavity and/or reducing the rod diameter along with optimizing the resonator design. Other improvements in efficiency which will be investigated include double passing the amplifier for better extraction. To complete this work, the laser system will be converted into a two-stage amplifier. A narrow band, lower power oscillator currently under development will be injected in to the amplifier to study the extraction and efficiency characteristics of the amplifier throughout the tuning range of Ti:Sapphire. Detailed beam quality measurements will also be made. Other work will include doubling the narrow band output for materials processing applications

  19. Length Variation, Heteroplasmy and Sequence Divergence in the Mitochondrial DNA of Four Species of Sturgeon (Acipenser)

    OpenAIRE

    Brown, J R; Beckenbach, K.; Beckenbach, A. T.; Smith, M.J

    1996-01-01

    The extent of mtDNA length variation and heteroplasmy as well as DNA sequences of the control region and two tRNA genes were determined for four North American sturgeon species: Acipenser transmontanus, A. medirostris, A. fulvescens and A. oxyrhnychus. Across the Continental Divide, a division in the occurrence of length variation and heteroplasmy was observed that was concordant with species biogeography as well as with phylogenies inferred from restriction fragment length polymorphisms (RFL...

  20. Transmission Performance Analysis of Fiber Optical Parametric Amplifiers for WDM System

    Directory of Open Access Journals (Sweden)

    Xiaohong Jiang

    2009-01-01

    Full Text Available A numerical analysis is presented on the long-haul wavelength-division multiplexing (WDM transmission system employing fiber-optic parametric amplifier (FOPA cascades based on one-pump FOPA model with Raman Effect taken into account. The end-to-end equalization scheme is applied to optimize the system features in terms of proper output powers and signal-to-noise ratios (SNRs in all the channels. The numerical results show that—through adjusting the fiber spans along with the number of FOPAs as well as the channel powers at the terminals in a prescribed way—the transmission distance and system performance can be optimized. By comparing the results generated by different lengths of fiber span, we come to the optimal span length to achieve the best transmission performance. Furthermore, we make a comparison among the long-haul WDM transmission systems employing different inline amplifiers, namely, FOPA, erbium-doped fiber amplifier (EDFA, and Fiber Raman Amplifier (FRA. FOPA demonstrates its advantage over the other two in terms of system features.

  1. FETAL FOOT LENGTH AND HAND LENGTH: RELATIONSHIP WITH CROWN RUMP LENGTH AND GESTATIONAL AGE

    Directory of Open Access Journals (Sweden)

    Garima

    2015-12-01

    Full Text Available BACKGROUND Estimation of gestational age of fetus is of great medicolegal importance. Multiple parameters of the fetal anatomical measurements are in use. However, gestational age assessment may be difficult in fetus with anencephaly, hydrocephalus, short limb dysplasia, post mortem destruction or in mutilated case. Study of literature suggests that fetal foot has a characteristic pattern of normal growth and the fetal foot shows gradual increase in length relative to the length of the embryo and could be used to estimate gestational age. The purpose of the present study is to determine the accuracy in estimating gestational age using fetal foot and hand length by studying its relation with crown rump length in the foetuses of Manipuri origin. AIMS AND OBJECTIVES 1 To study the relationship between fetal crown rump length and fetal hand and foot length, thereby determining the accuracy in estimating gestational age by a cross-sectional study. MATERIALS AND METHODS A total of 100 formalin fixed fetuses of Manipuri origin, obtained from the Department of Obstetrics and Gynaecology, Regional Institute of Medical Sciences, Imphal, were included in the study, carried out in the Department of Anatomy, from February 2015 to July 2015. The parameters studied were crown rump length, foot length and hand length of fetuses. The data was analysed using SPSS software by regression analysis. Graphs were also plotted to determine pattern of growth and their correlation with crown rump length if any. RESULTS A total of 100 fetuses were studied, of which 43 were females and 57 were males. The mean foot length and hand length progressively increased with increase in crown rump length. Measurements were not significantly different in right or left side or among male and female fetuses. A statistically significant linear relationship was seen between foot length and crown rump length of the fetus (r=0.980, p<0.0001 and hand length and crown rump length of the fetus

  2. An X-band GaN combined solid-state power amplifier

    International Nuclear Information System (INIS)

    Based on a self-developed AlGaN/GaN HEMT with 2.5 mm gate width technology on a SiC substrate, an X-band GaN combined solid-state power amplifier module is fabricated. The module consists of an AlGaN/GaN HEMT, Wilkinson power couplers, DC-bias circuit and microstrip line. For each amplifier, we use a bipolar DC power source. Special RC networks at the input and output and a resistor between the DC power source and the gate of the transistor at the input are used for cancellation of self-oscillation and crosstalk of low-frequency of each amplifier. At the same time, branches of length 3λ/4 for Wilkinson power couplers are designed for the elimination of self-oscillation of the two amplifiers. Microstrip stub lines are used for input matching and output matching. Under Vds = 27 V, Vgs = -4.0 V, CW operating conditions at 8 GHz, the amplifier module exhibits a line gain of 5.6 dB with power added efficiency of 23.4%, and output power of 41.46 dBm (14 W), and the power gain compression is 3 dB. Between 8 and 8.5 GHz, the variation of output power is less than 1.5 dB.

  3. Theoretical and experimental research of supercontinuum generation in an ytterbium-doped fiber amplifier.

    Science.gov (United States)

    Lei, Chengmin; Jin, Aijun; Song, Rui; Chen, Zilun; Hou, Jing

    2016-05-01

    The theoretical research of supercontinuum (SC) generation in a fiber amplifier system has been seldom reported. For the purpose of further understanding the mechanism of SC generation in fiber amplifiers, we propose a combined numerical model of the laser rate equations and the generalized non-linear Schrödinger equation to simulate the amplification of 1060 nm picosecond pulses and their spectral broadening in an ytterbium-doped fiber amplifier. The calculation results of this model are compared with the experimental results under the same conditions and a good agreement is achieved. We find that the pulse is gain amplified initially, and then dominated by stimulated Raman scattering in the normal dispersion region. In anomalous dispersion region, modulation instability, higher-order soliton fission and soliton self-frequency shift dominates the spectral broadening. It is found numerically and experimentally that the length of the gain fiber and the 976 nm pump power are the most imperative parameters to control the output power, spectral range and flatness of the SC. The pulse width of signal pulse also plays a part in influencing SC generation. The results verify that our model is promising for analyzing the physical processes of pulse evolution and SC generation in a fiber amplifier system. PMID:27137540

  4. A megajoule class krypton fluoride amplifier for single shot, high gain ICF application

    International Nuclear Information System (INIS)

    A design study is underway to define the optimal architecture for a KrF laser system which will deliver 10 MJ of 248-nm light to an ICF target. The authors present one approach which incorporates final power amplifiers in the megajoule class, achieving 10 MJ with only four final amplifiers. Each double-pass laser amplifier employs two-sided electron-beam pumping of the laser gas medium. Analysis of the design is based on a Monte-Carlo electron-beam deposition code, a one-dimensional, time-dependent kinetics code, and pulsed power circuit modeling. Linear dimensions of the amplifier's extracted gain volume are 6.25 m in height and length and 5.12 m in width. Each amplifier handles 160 angularly multiplexed laser channels. The one-amagat, krypton-rich laser medium is e-beam pumped at 60 kW cm/sup -3/ (4 MA at 3.3 MV) over the 2-microsecond duration of the laser beam pulse train

  5. A megajoule class krypton fluoride amplifier for single shot, high gain ICF application

    International Nuclear Information System (INIS)

    A design study is underway to define the optimal architecture for a KrF laser system which will deliver 10 MJ of 248-nm light to an ICF target. We present one approach which incorporates final power amplifiers in the megajoule class, achieving 10 MJ with four final amplifiers. Each double-pass laser amplifier employs two-sided electron-beam pumping of the laser gas medium. Details of the design are based on a Monte-Carlo electron-beam deposition code, a one-dimensional, time-dependent kinetics code, and pulsed power circuit modeling. Linear dimensions of the amplifier's extracted gain volume are 6.25 m in height and length and 5.12 m in width. Each amplifier handles 160 angularly multiplexed laser channels. The one-amagat, krypton-rich laser medium is e-beam pumped at 60-kW cm/sup /minus/3/ (4-MA at3.3-MV) over the 2-microsecond duration of the laser beam pulse train. 5 refs., 4 figs

  6. Single mode terahertz quantum cascade amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Y., E-mail: yr235@cam.ac.uk; Wallis, R.; Shah, Y. D.; Jessop, D. S.; Degl' Innocenti, R.; Klimont, A.; Kamboj, V.; Beere, H. E.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge (United Kingdom)

    2014-10-06

    A terahertz (THz) optical amplifier based on a 2.9 THz quantum cascade laser (QCL) structure has been demonstrated. By depositing an antireflective coating on the QCL facet, the laser mirror losses are enhanced to fully suppress the lasing action, creating a THz quantum cascade (QC) amplifier. Terahertz radiation amplification has been obtained, by coupling a separate multi-mode THz QCL of the same active region design to the QC amplifier. A bare cavity gain is achieved and shows excellent agreement with the lasing spectrum from the original QCL without the antireflective coating. Furthermore, a maximum optical gain of ∼30 dB with single-mode radiation output is demonstrated.

  7. Ultrashort pulse amplification in cryogenically cooled amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Backus, Sterling J.; Kapteyn, Henry C.; Murnane, Margaret Mary

    2004-10-12

    A laser amplifier system amplifies pulses in a single "stage" from .about.10.sup.-9 joules to more than 10.sup.-3 joules, with average power of 1-10 watts, and beam quality M.sup.2 <2. The laser medium is cooled substantially below room temperature, as a means to improve the optical and thermal characteristics of the medium. This is done with the medium inside a sealed, evacuated or purged cell to avoid moisture or other materials condensing on the surface. A "seed" pulse from a separate laser is passed through the laser medium, one or more times, in any of a variety of configurations including single-pass, multiple-pass, and regenerative amplifier configurations.

  8. Transistorized pulse amplifiers (A.I.T.)

    International Nuclear Information System (INIS)

    The two amplifiers whose design and operation are described in this report have been studied for neutron detection units used in piles. They are designed to allow an important reduction of the volume and of the weight of the detector and its amplifier, and to simplify the operation of the detection assembly. To these characteristics can be added the mechanical and electrical robustness and the very reduced micro-phony. The first transistorized amplifier (AIT.1) is simple, very robust, and can be used for radioprotection installations. The second (AIT.4) has a better performance and makes it possible to replace the APT.2 in most of its applications (it has even been used satisfactorily in an apparatus where the micro-phony and the sensitivity to interference of the APT.2 made this latter unusable). (author)

  9. An automated test facility for neutronic amplifiers

    International Nuclear Information System (INIS)

    Neutronic amplifiers are used at the Chalk River Laboratory in applications such as neutron flux monitoring and reactor control systems. Routine preventive maintenance of control and safety systems included annual calibration and characterization of the neutronic amplifiers. An investigation into the traditional methods of annual routine maintenance of amplifiers concluded that frequency and phase response measurements in particular were labour intensive and subject to non-repeatable errors. A decision was made to upgrade testing methods and facilities by using programmable test equipment under the control of a computer. In order to verify the results of the routine measurements, expressions for the transfer functions were derived from the circuit diagrams. Frequency and phase responses were then calculated and plotted thus providing a bench-mark to which the test results can be compared. (author)

  10. Generation and characterization of the human neutralizing antibody fragment Fab091 against rabies virus

    OpenAIRE

    Li, Chen; Zhang, Feng; Lin, Hong; Wang, Zhong-can; Liu, Xin-jian; Feng, Zhen-qing; Zhu, Jin; Guan, Xiao-hong

    2011-01-01

    Aim: To transform the human anti-rabies virus glycoprotein (anti-RABVG) single-chain variable fragment (scFv) into a Fab fragment and to analyze its immunological activity. Methods: The Fab gene was amplified using overlap PCR and inserted into the vector pComb3XSS. The recombinant vector was then transformed into E coli Top10F' for expression and purification. The purified Fab was characterized using SDS-PAGE, Western blotting, indirect ELISA, competitive ELISA, and the fluorescent antibody ...

  11. The length distribution of frangible biofilaments.

    Science.gov (United States)

    Michaels, Thomas C T; Yde, Pernille; Willis, Julian C W; Jensen, Mogens H; Otzen, Daniel; Dobson, Christopher M; Buell, Alexander K; Knowles, Tuomas P J

    2015-10-28

    A number of different proteins possess the ability to polymerize into filamentous structures. Certain classes of such assemblies can have key functional roles in the cell, such as providing the structural basis for the cytoskeleton in the case of actin and tubulin, while others are implicated in the development of many pathological conditions, including Alzheimer's and Parkinson's diseases. In general, the fragmentation of such structures changes the total number of filament ends, which act as growth sites, and hence is a key feature of the dynamics of filamentous growth phenomena. In this paper, we present an analytical study of the master equation of breakable filament assembly and derive closed-form expressions for the time evolution of the filament length distribution for both open and closed systems with infinite and finite monomer supply, respectively. We use this theoretical framework to analyse experimental data for length distributions of insulin amyloid fibrils and show that our theory allows insights into the microscopic mechanisms of biofilament assembly to be obtained beyond those available from the conventional analysis of filament mass only. PMID:26520548

  12. The length distribution of frangible biofilaments

    Science.gov (United States)

    Michaels, Thomas C. T.; Yde, Pernille; Willis, Julian C. W.; Jensen, Mogens H.; Otzen, Daniel; Dobson, Christopher M.; Buell, Alexander K.; Knowles, Tuomas P. J.

    2015-10-01

    A number of different proteins possess the ability to polymerize into filamentous structures. Certain classes of such assemblies can have key functional roles in the cell, such as providing the structural basis for the cytoskeleton in the case of actin and tubulin, while others are implicated in the development of many pathological conditions, including Alzheimer's and Parkinson's diseases. In general, the fragmentation of such structures changes the total number of filament ends, which act as growth sites, and hence is a key feature of the dynamics of filamentous growth phenomena. In this paper, we present an analytical study of the master equation of breakable filament assembly and derive closed-form expressions for the time evolution of the filament length distribution for both open and closed systems with infinite and finite monomer supply, respectively. We use this theoretical framework to analyse experimental data for length distributions of insulin amyloid fibrils and show that our theory allows insights into the microscopic mechanisms of biofilament assembly to be obtained beyond those available from the conventional analysis of filament mass only.

  13. Cryogenic cooling for high power laser amplifiers

    OpenAIRE

    Perin J.P.; Millet F.; Divoky M.; Rus B.

    2013-01-01

    Using DPSSL (Diode Pumped Solid State Lasers) as pumping technology, PW-class lasers with enhanced repetition rates are developed. Each of the Yb YAG amplifiers will be diode-pumped at a wavelength of 940 nm. This is a prerequisite for achieving high repetition rates (light amplification duration 1 millisecond and repetition rate 10 Hz). The efficiency of DPSSL is inversely proportional to the temperature, for this reason the slab amplifier have to be cooled at a temperature in the range of 1...

  14. Transportable setup for amplifier phase fidelity measurements

    Science.gov (United States)

    Tröbs, M.; Bogan, C.; Barke, S.; Kühn, G.; Reiche, J.; Heinzel, G.; Danzmann, K.

    2015-05-01

    One possible laser source for the Laser Interferometer Space Antenna (LISA) consists of an Ytterbium-doped fiber amplifier originally developed for inter-satellite communication, seeded by the laser used for the technology demonstrator mission LISA Pathfinder. LISA needs to transmit clock information between its three spacecraft to correct for phase noise between the clocks on the individual spacecraft. For this purpose phase modulation sidebands at GHz frequencies will be imprinted on the laser beams between spacecraft. Differential phase noise between the carrier and a sideband introduced within the optical chain must be very low. We report on a transportable setup to measure the phase fidelity of optical amplifiers.

  15. Optimization of Pr3+:ZBLAN fiber amplifiers

    DEFF Research Database (Denmark)

    Pedersen, B.; Miniscalco, J. W.; Quimby, R. S.

    1992-01-01

    Experimental parameters have been measured and used in a quantitative model of Pr3+-doped fluorozirconate fiber amplifiers. The optimum cutoff wavelength was determined to be 800 nm and the gain for 400 mW of pump was found to increase from 12 to 34 dB if the NA was increased from 0.15 to 0.......25. Lengthening the metastable state lifetime from 110 to 300 μs would significantly improve amplifier performance while concentration quenching can appreciably degrade it...

  16. Beyond nonlinear saturation of backward Raman amplifiers

    Science.gov (United States)

    Barth, Ido; Toroker, Zeev; Balakin, Alexey A.; Fisch, Nathaniel J.

    2016-06-01

    Backward Raman amplification is limited by relativistic nonlinear dephasing resulting in saturation of the leading spike of the amplified pulse. Pump detuning is employed to mitigate the relativistic phase mismatch and to overcome the associated saturation. The amplified pulse can then be reshaped into a monospike pulse with little precursory power ahead of it, with the maximum intensity increasing by a factor of two. This detuning can be employed advantageously both in regimes where the group velocity dispersion is unimportant and where the dispersion is important but small.

  17. Operational amplifier circuits analysis and design

    CERN Document Server

    Nelson, J C C

    1995-01-01

    This book, a revised and updated version of the author's Basic Operational Amplifiers (Butterworths 1986), enables the non-specialist to make effective use of readily available integrated circuit operational amplifiers for a range of applications, including instrumentation, signal generation and processing.It is assumed the reader has a background in the basic techniques of circuit analysis, particularly the use of j notation for reactive circuits, with a corresponding level of mathematical ability. The underlying theory is explained with sufficient but not excessive, detail. A range of compu

  18. Optical Pulse Compression Based on High-doped Erbium Fiber Amplifier and Standard Single-mode Fiber

    Institute of Scientific and Technical Information of China (English)

    REN Jing; JIA Dong-fang; LIU Yang; LI Ya-bin

    2008-01-01

    Proposed is a novel optical pulse compression technique based on high-doped erbium fiber amplifier and standard single-mode fiber(SMF). We used the amplifier with the erbium ion concentration of 6.3×10-3 to amplify a hyperbolic secant pulse from a regeneratively mode-locked fiber laser. The central wavelength, pulsewidth and peak power of the pulse are 1 550 nm, 12.5 ps and 3 mW, respectively. Then the amplified pulse with peak power level corresponding to a higher-order soliton is compressed when it propagates through a 3-km-long single-mode fiber. Studied are the compressed pulses under different pump powers and fiber lengths. The results show that it can get a narrower pulse, and solve the difficulty that pulses at low power can not be compressed directly in the fiber. And the construct is compact.

  19. A W-band two-stage cascode amplifier with gain of 25.7 dB

    International Nuclear Information System (INIS)

    A W-band two-stage amplifier MMIC has been developed using a fully passivated 2 × 20 μm gate-width and 0.15 μm gate-length InP-based high electron mobility transistor (HEMT) technology. The two-stage amplifier has been realized in combination with a coplanar waveguide technique and cascode topology, thus leading to a compact chip-size of 1.85 × 0.932 mm2 and an excellent small-signal gain of 25.7 dB at 106 GHz. Additionally, an inter-digital coupling capacitor blocks low-frequency signal, thereby enhancing the stability of the amplifier. The successful design of the two-stage amplifier MMIC indicates that InP HEMT technology has a great potential for W-band applications. (semiconductor integrated circuits)

  20. Peak power tunable mid-infrared oscillator pumped by a high power picosecond pulsed fiber amplifier with bunch output

    Science.gov (United States)

    Wei, Kaihua; Guo, Yan; Lai, Xiaomin; Fan, Shanhui

    2016-07-01

    A high power mid-infrared optical parametric oscillator (OPO) with picosecond pulse bunch output is experimentally demonstrated. The pump source was a high power master oscillation power amplifier (MOPA) picosecond pulsed fiber amplifier. The seed of the MOPA was a gain-switched distributed Bragg reflector (DBR) laser diode (LD) with picosecond pulse operation at a high repetition rate. The seed laser was amplified to 50 W by two-stage pre-amplifiers and a large mode area (LMA) Yb fiber based power-amplifier. A fiber-pigtailed acousto-optic modulator with the first order diffraction transmission was inserted into the second pre-amplifier to form a picosecond pulse bunch train and to change the peak power simultaneously. The power-amplified pulse bunches were focused to pump a wavelength-tunable OPO for emitting high power mid-infrared laser. By adjusting the OPO cavity length, the maximum average idler powers obtained at 3.1, 3.3 and 3.5 μm were 7, 6.6 and 6.4 W respectively.