Sample records for alis-flp amplified ligation

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

    DEFF Research Database (Denmark)

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


    A DNA fingerprinting method known as ALIS-FLP (amplified ligation selected fragment-length polymorphism) has been developed for selective and specific amplification of restriction fragments from TspRI restriction endonuclease digested genomic DNA. The method is similar to AFLP, but differs in tha...... combining the advantages of the AFLP technique with a simple, rapid and cheap polymerase chain reaction product detection method.......A DNA fingerprinting method known as ALIS-FLP (amplified ligation selected fragment-length polymorphism) has been developed for selective and specific amplification of restriction fragments from TspRI restriction endonuclease digested genomic DNA. The method is similar to AFLP, but differs...... 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 highlighted, i.e. its...

  2. A ligation-triggered DNAzyme cascade for amplified fluorescence detection of biological small molecules with zero-background signal. (United States)

    Lu, Li-Min; Zhang, Xiao-Bing; Kong, Rong-Mei; Yang, Bin; Tan, Weihong


    Many types of fluorescent sensing systems have been reported for biological small molecules. Particularly, several methods have been developed for the recognition of ATP or NAD(+), but they only show moderate sensitivity, and they cannot discriminate either ATP or NAD(+) from their respective analogues. We have addressed these limitations and report here a dual strategy which combines split DNAzyme-based background reduction with catalytic and molecular beacon (CAMB)-based amplified detection to develop a ligation-triggered DNAzyme cascade, resulting in ultrahigh sensitivity. First, the 8-17 DNAzyme is split into two separate oligonucleotide fragments as the building blocks for the DNA ligation reaction, thereby providing a zero-background signal to improve overall sensitivity. Next, a CAMB strategy is further employed for amplified signal detection achieved through cycling and regenerating the DNAzyme to realize the true enzymatic multiple turnover (one enzyme catalyzes the cleavage of several substrates) of catalytic beacons. This combination of zero-background signal and signal amplification significantly improves the sensitivity of the sensing systems, resulting in detection limits of 100 and 50 pM for ATP and NAD(+), respectively, much lower than those of previously reported biosensors. Moreover, by taking advantage of the highly specific biomolecule-dependence of the DNA ligation reaction, the developed DNAzyme cascades show significantly high selectivity toward the target cofactor (ATP or NAD(+)), and the target biological small molecule can be distinguished from its analogues. Therefore, as a new and universal platform for the design of DNA ligation reaction-based sensing systems, this novel ligation-triggered DNAzyme cascade method may find a broad spectrum of applications in both environmental and biomedical fields.

  3. Antioxidant amplifies antibiotic protection in the cecal ligation and puncture model of microbial sepsis through interleukin-10 production. (United States)

    Kotake, Yashige; Moore, Danny R; Vasquez-Walden, Angelica; Tabatabaie, Tahereh; Sang, Hong


    Preadministration of antioxidants such as pyrrolidine dithiocarbamate (PDTC) and phenyl N-tert-butyl nitrone (PBN) protects animals from lethality in sepsis models. However, the requirement of preadministration greatly diminishes the clinical significance of these studies. Although the synthetic antioxidant PBN has been shown to effectively protect rodents from lethality in endotoxemia (lipopolysaccharide [LPS] model), preliminary screening indicates that pre- or postadministration of PBN does not protect in the rat cecal ligation and puncture (CLP) model. We show in this report that in a rat CLP model, the administration of PBN (150 mg/kg, 30 min after CLP) followed by the antibiotic imipenem (IMP; 10 mg/kg, 1 h after CLP) significantly increased survival compared with other single treatment groups. Previously, we have shown that PBN's protection in a rat LPS model is mediated by the overproduction of the anti-inflammatory cytokine interleukin (IL)-10. We show in this study that the increase in survival found in the PBN + IMP-treated group was abrogated by immunoneutralization with anti-IL-10 antibody, indicating that endogenous IL-10 is an effective protective factor. Plasma LPS levels were shown to be elevated after imipenem treatment, and the increased LPS level could have assisted to overproduce endogenous IL-10, as in the case of the PBN-treated LPS model. Statistical analysis indicated that the increase of IL-10 in PBN + IMP-treated group at early time period has significant association to the improvement of survival.

  4. Highly selective and sensitive electrochemical biosensor for ATP based on the dual strategy integrating the cofactor-dependent enzymatic ligation reaction with self-cleaving DNAzyme-amplified electrochemical detection. (United States)

    Lu, Lu; Si, Jing Cao; Gao, Zhong Feng; Zhang, Yu; Lei, Jing Lei; Luo, Hong Qun; Li, Nian Bing


    A dual strategy that combines the adenosine triphosphate (ATP)-dependent enzymatic ligation reaction with self-cleaving DNAzyme-amplified electrochemical detection is employed to construct the biosensor. In this design, the methylene blue-labeled hairpin-structured DNA was self-assembled onto a gold electrode surface to prepare the modified electrode through the interaction of Au-S bond. In the procedure of ATP-dependent ligation reaction, when the specific cofactor ATP was added, the two split oligonucleotide fragments of 8-17 DNAzyme were linked by T4 DNA ligase and then released to hybridize with the labeled hairpin-structured DNA substrate. The linked 8-17 DNAzyme catalyzes the cleavage of the hairpin-structured substrate by the addition of Zn(2+), causing the methylene blue which contains high electrochemical activity to leave the surface of the gold electrode, therefore generating a dramatic decrease of electrochemical signal. The decrease of peak current was readily measured by square wave voltammetry and a relatively low detection limit (0.05 nM) was obtained with a linear response range from 0.1 to 1000 nM. By taking advantage of the highly specific cofactor dependence of the DNA ligation reaction, the proposed ligation-induced DNAzyme cascades demonstrate ultrahigh selectivity toward the target cofactor ATP. A catalytic and molecular beacons strategy is further adopted to amplify the electrochemical signal detection achieved by cycling and regenerating the 8-17 DNAzyme to realize enzymatic multiple turnover, thus one DNAzyme can catalyze the cleavage of several hairpin-structured substrates, which improves the sensitivity of the newly designed electrochemical sensing system.

  5. Ligation-based assembly for constructing mouse synthetic scFv libraries by chain shuffling with in vivo-amplified VH and VL fragments. (United States)

    Nishi, Michiru; Jian, Nan; Yamamoto, Keiko; Seto, Haruyo; Nishida, Yuichi; Tonoyama, Yasuhiro; Shimizu, Nobuyoshi; Nishi, Yoshisuke


    In vitro assembly of two or three PCR fragments using primers is a common method of constructing scFv fragments for display on the surface of phage. However, mismatch annealing often occurs during in this step, leading to cloning and display of incomplete Fab or scFv fragments. To overcome this limitation, we developed a ligation-based two-fragment assembly (LTFA) protocol that involved separately cloning VH and Vκ fragments into the high-copy-number plasmid pUC18. The VH and Vκ fragments had randomized complementarity-determining region 3 (CDR3) and were joined with a peptidyl linker composed of (G4S)3. Using this approach, complete sequences of scFv fragments were successfully constructed, and the sequencing of 83 scFv clones revealed that none of the sequences, including the linker region, contained deletions or mutations. In contrast, linker sequences generated using a conventional two-fragment PCR assembly (TFPA) protocol often contained sequence anomalies, including large truncations. Using the LTFA protocol, a final library size of 1.0×10(8)cfu was achieved. Examination of the amino acid profiles of the generated scFv fragments within the randomized regions introduced using degenerate codons did not detect any bias from that expected based on stochastic distribution. After several cycles of panning with this library, antigen-specific scFvs against two reference antigens, hen egg lysozyme and streptavidin were detected. In addition, scFvs with specificity against peptidyl antigens in the loop region of the Medaka ortholog of human C6orf89, which encodes a histone deacetylase enhancer that interacts with the bombesin receptor, were also obtained. The LTFA protocol developed here is robust and allows for the easy construction of integral scFv fragments compared with conventional TFPA. Utilizing LTFA, other CDRs can be readily combined. This approach also allows for the in vitro maturation of scFv fragments by separately introducing randomization in CDRs or

  6. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana; Bertozzi, Carolyn


    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  7. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn (Berkeley, CA)


    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  8. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn R. (Berkeley, CA)


    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g. on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  9. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn Ruth (Berkeley, CA)


    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  10. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn Ruth (Berkeley, CA)


    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  11. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn R. (Berkeley, CA)


    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  12. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn R. (Berkeley, CA)


    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  13. Clinical application of a ligation-independent pathway of multiplex ligation-dependent probe amplification for the determination of quinolone susceptibility of Streptococcus pneumoniae. (United States)

    Uno, Naoki; Araki, Nobuko; Kaku, Norihito; Kosai, Kosuke; Hasegawa, Hiroo; Yanagihara, Katsunori


    We previously uncovered a ligation-independent pathway of multiplex ligation-dependent probe amplification (MLPA) through which products of MLPA could be amplified without both hybridization and ligation reactions. Here, we utilized this pathway to detect an antibiotic resistance mutation of quinolones in Streptococcus pneumoniae.

  14. Precise sequential DNA ligation on a solid substrate: solid-based rapid sequential ligation of multiple DNA molecules. (United States)

    Takita, Eiji; Kohda, Katsunori; Tomatsu, Hajime; Hanano, Shigeru; Moriya, Kanami; Hosouchi, Tsutomu; Sakurai, Nozomu; Suzuki, Hideyuki; Shinmyo, Atsuhiko; Shibata, Daisuke


    Ligation, the joining of DNA fragments, is a fundamental procedure in molecular cloning and is indispensable to the production of genetically modified organisms that can be used for basic research, the applied biosciences, or both. Given that many genes cooperate in various pathways, incorporating multiple gene cassettes in tandem in a transgenic DNA construct for the purpose of genetic modification is often necessary when generating organisms that produce multiple foreign gene products. Here, we describe a novel method, designated PRESSO (precise sequential DNA ligation on a solid substrate), for the tandem ligation of multiple DNA fragments. We amplified donor DNA fragments with non-palindromic ends, and ligated the fragment to acceptor DNA fragments on solid beads. After the final donor DNA fragments, which included vector sequences, were joined to the construct that contained the array of fragments, the ligation product (the construct) was thereby released from the beads via digestion with a rare-cut meganuclease; the freed linear construct was circularized via an intra-molecular ligation. PRESSO allowed us to rapidly and efficiently join multiple genes in an optimized order and orientation. This method can overcome many technical challenges in functional genomics during the post-sequencing generation.

  15. Operational amplifiers

    CERN Document Server

    Dostal, Jiri


    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

  16. [Post-tubal ligation syndrome]. (United States)

    Satoh, K; Osada, H


    Post-tubal ligation syndrome includes pain during intercourse, aching lower back, premenstrual tension syndrome, difficulty in menstruating, uterine hemorrhage, and absence of menstruation. The syndrome is caused by blood circulation problems in and around the Fallopian tubes and ovaries, pressure on nerves, and intrapelvic adhesion. Differentiating between this syndrome and endometritis during diagnosis and differentiating between functional hemorrhage due to hormonal abnormality and anatomical hemorrhage due to polyp or tumor is very important. Since the symptoms of this syndrome are mild, simple symptomatic treatment is sufficient in most cases. In some cases, however, desquamation surgery or reversal of tubal ligation may be necessary. Endoscopic surgery is also available. In Japan, because of widespread use of condoms and IUDs, tubal ligation is not very common.

  17. Ligation-Independent Mechanism of Multiplex Ligation-Dependent Probe Amplification


    Uno, Naoki; Yanagihara, Katsunori


    Multiplex ligation-dependent probe amplification (MLPA) is a widely used technique for detecting genomic structural variants. The technique is based on hybridization and ligation, followed by amplification of the ligation products. Therefore, ligation is considered a fundamental process that determines the feasibility and fidelity of MLPA. However, despite the widespread use of this technique, its reaction mechanism has not been fully analyzed. Herein, we describe a ligation-independent pathw...

  18. The postal tubal ligation syndrome. (United States)

    Faber, E; Rocko, J M; Timmes, J J; Zolli, A F


    The frequency of symptoms following tubal ligation calls for an examination of the basic problem with the methods now used. This discussion recommends a modification of tubal ligation which as performed during the past 2-1/2 years has been symptom free, post operatively. What is meant by symptom free is those symptoms which can be directly related to tubal ligation. Symptomatology is complex and insidious. Characteristically, there is a latent period of no symptoms. This asymptomatic period may be totally subjective and may last several years during which time the correlation between surgery and symptoms is obscured. This is particularly the case if purely symptomatic therapeusis has had some degree of success. The latest period is followed by the gradual development of the following: menstrual disorders; abdominal pain which is usually located in the lower abdomen and is of 2 varieties, i.e., dysmenorrhea and nonmenstrual pain; and infection. Physical examination demonstrates little. This set of symptoms, which has been documented also by Poma et al., and when taken as a whole, constitutes a syndrome which should be termed the posttubal ligation syndrome. These patients give a history of repeat X-rays, biopsies, endoscopies, and surgical exploration. Some of these patients have had 4 or 5 celiotomies. A modification of the traditional method of tubal ligation definitely requires consideration. The characteristics of the oviducts which need mention and emphasis are reviewed. On the basis of the reviewed considerations, it becomes obvious that smooth transport of the ovum is a necessity and that obstruction in the tubes will cause a reaction similar to obstruction anywhere in the body. Tubal ligation should be performed in such a manner so as not to obstruct the ova from passing down the tube. The tubes should be cut fairly close to the uterus and be tied. The rest of the tube from fimbria to the isthmus should be left open. In this manner, the ovum passes into the

  19. [Latex ligation in treatment of chronic hemorrhoids]. (United States)

    Ektov, V N; Somov, K A


    We analyzed the results of treatment of 432 patients with chronic hemorrhoids using different variants of latex ligation. New technique including ligation of mucosa and submucosa of low-ampullar rectum providing ligation of hemorrhoidalvessels, lifting and recto-anal repair is developed and suggested. This method is advisable to use in case of chronic internal hemorrhoids stages I and II. The authors recommend simultaneous combined ligation of mucosa of low-ampullar rectum and internal hemorrhoids for stages III and IV. Different variants of latex ligation with external hemorrhoids excision were used in 103 patients. Pointed variants of latex ligation preserve important advantages including mini-invasiveness, simplicity and wide availability, low cost. Good remote results were obtained after these procedures in 87.3% of observations. Suggested tactics extends use of latex ligation and increases its effectiveness in treatment of different stages and forms of chronic hemorrhoids.

  20. Enzymatic Ligation Creates Discrete Multi-Nanoparticle Building Blocks for Self-Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Claridge, Shelley A.; Mastroianni, Alexander J.; Au, Yeung B.; Liang, Huiyang W.; Micheel, Christine M.; Frechet, Jean M.J.; Alivisatos, A. Paul


    Enzymatic ligation of discrete nanoparticle?DNA conjugates creates nanoparticle dimer and trimer structures in which the nanoparticles are linked by single-stranded DNA, rather than double-stranded DNA as in previous experiments. Ligation is verified by agarose gel and small-angle X-ray scattering. This capability is utilized in two ways: first to create a new class of multiparticle building blocks for nanoscale self-assembly; second to develop a system which can amplify a population of discrete nanoparticle assemblies.

  1. Enzyme Treatment-Free and Ligation-Independent Cloning Using Caged Primers in Polymerase Chain Reactions

    Directory of Open Access Journals (Sweden)

    Akinori Kuzuya


    Full Text Available A new simple scheme for constructing recombinant vectors that does not require any restriction enzyme, ligase, or any other special enzyme treatment has been developed. By using caged primers in PCR, unnatural sticky-ends of any sequence, which are sufficiently long for ligation-independent cloning (LIC, are directly prepared on the product after a brief UVA irradiation. Target genes and vectors amplified by this light-assisted cohesive-ending (LACE PCR join together in the desired arrangement in a simple mixture of them, tightly enough to be repaired and ligated in competent cells.

  2. Determinants of tubal ligation in Puebla, Mexico. (United States)

    Rudzik, Alanna E F; Leonard, Susan H; Sievert, Lynnette L


    Tubal ligation provides an effective and reliable method by which women can choose to limit the number of children they will bear. However, because of the irreversibility of the procedure and other potential disadvantages, it is important to understand factors associated with women's choice of this method of birth control. Between May 1999 and August 2000, data were collected from 755 women aged 40 to 60 years from a cross-section of neighborhoods of varying socio-economic make-up in Puebla, Mexico, finding a tubal ligation rate of 42.2%. Multiple logistic regression models were utilized to examine demographic, socio-economic, and reproductive history characteristics in relation to women's choice of tubal ligation. Regression analyses were repeated with participants grouped by age to determine how the timing of availability of tubal ligation related to the decision to undergo the procedure. The results of this study suggest that younger age, more education, use of some forms of birth control, and increased parity were associated with women's decisions to undergo tubal ligation. The statistically significant difference of greater tubal ligation and lower hysterectomy rates across age groups reflect increased access to tubal ligation in Mexico from the early 1970s, supporting the idea that women's choice of tubal ligation was related to access.

  3. Cloning of DNA fragments: ligation reactions in agarose gel. (United States)

    Furtado, Agnelo


    Ligation reactions to ligate a desired DNA fragment into a vector can be challenging to beginners and especially if the amount of the insert is limiting. Although additives known as crowding agents, such as PEG 8000, added to the ligation mixes can increase the success one has with ligation reactions, in practice the amount of insert used in the ligation can determine the success or the failure of the ligation reaction. The method described here, which uses insert DNA in gel slice added directly into the ligation reaction, has two benefits: (a) using agarose as the crowding agent and (b) reducing steps of insert purification. The use of rapid ligation buffer and incubation of the ligation reaction at room temperature greatly increase the efficiency of the ligation reaction even for blunt-ended ligation.

  4. Orchidopexy san ligation technique of orchidopexy

    Directory of Open Access Journals (Sweden)

    Jain Vishal


    Full Text Available Pediatric hernia surgery is the most common operation done by pediatric general surgeons and it is a core competency for general surgeons in the developing world. Herniotomy is performed for the surgical repair of hernia and along with orchiopexy for the closure of associated patent processus vaginalis. Traditionally, ligation of hernial sac during orchiopexy is considered mandatory to prevent postoperative development of hernia. The present report was designed to study the results of non-ligation of the hernial sac during orchiopexy. It was found that non-ligation has no untoward effect on early complications and recurrence rate on long-term follow-up. It is suggested that it is not necessary to ligate the hernial sac during orchiopexy in children.

  5. Comparison and transfer testing of multiplex ligation detection methods for GM plants

    Directory of Open Access Journals (Sweden)

    Ujhelyi Gabriella


    Full Text Available Abstract Background With the increasing number of GMOs on the global market the maintenance of European GMO regulations is becoming more complex. For the analysis of a single food or feed sample it is necessary to assess the sample for the presence of many GMO-targets simultaneously at a sensitive level. Several methods have been published regarding DNA-based multidetection. Multiplex ligation detection methods have been described that use the same basic approach: i hybridisation and ligation of specific probes, ii amplification of the ligated probes and iii detection and identification of the amplified products. Despite they all have this same basis, the published ligation methods differ radically. The present study investigated with real-time PCR whether these different ligation methods have any influence on the performance of the probes. Sensitivity and the specificity of the padlock probes (PLPs with the ligation protocol with the best performance were also tested and the selected method was initially validated in a laboratory exchange study. Results Of the ligation protocols tested in this study, the best results were obtained with the PPLMD I and PPLMD II protocols and no consistent differences between these two protocols were observed. Both protocols are based on padlock probe ligation combined with microarray detection. Twenty PLPs were tested for specificity and the best probes were subjected to further evaluation. Up to 13 targets were detected specifically and simultaneously. During the interlaboratory exchange study similar results were achieved by the two participating institutes (NIB, Slovenia, and RIKILT, the Netherlands. Conclusions From the comparison of ligation protocols it can be concluded that two protocols perform equally well on the basis of the selected set of PLPs. Using the most ideal parameters the multiplicity of one of the methods was tested and 13 targets were successfully and specifically detected. In the

  6. Cross-differential amplifier (United States)

    Hajimiri, Seyed-Ali (Inventor); Kee, Scott D. (Inventor); Aoki, Ichiro (Inventor)


    A cross-differential amplifier is provided. The cross-differential amplifier includes an inductor connected to a direct current power source at a first terminal. A first and second switch, such as transistors, are connected to the inductor at a second terminal. A first and second amplifier are connected at their supply terminals to the first and second switch. The first and second switches are operated to commutate the inductor between the amplifiers so as to provide an amplified signal while limiting the ripple voltage on the inductor and thus limiting the maximum voltage imposed across the amplifiers and switches.

  7. Portable musical instrument amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Christian, David E. (Danbury, CT)


    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.

  8. Principles and applications of Ligation Mediated PCR methods for DNA-based typing of microbial organisms. (United States)

    Krawczyk, Beata; Kur, Józef; Stojowska-Swędrzyńska, Karolina; Śpibida, Marta


    A significant number of DNA-based techniques has been introduced into the field of microorganisms' characterization and taxonomy. These genomic fingerprinting methods were developed to detect DNA sequence polymorphisms by using general principles, such as restriction endonuclease analysis, molecular hybridization, and PCR amplification. In recent years, some alternative techniques based on ligation of oligonucleotide adapters before DNA amplification by PCR, known as Ligation-Mediated PCR methods (LM PCR), have been successfully applied for the typing of microorganisms below the species level. These molecular methods include: Amplified Fragment Length Polymorphism (AFLP), Amplification of DNA fragments Surrounding Rare Restriction Sites (ADSRRS), PCR Melting Profiles (PCR MP), Ligation Mediated PCR/Shifter (LM PCR/Shifter), Infrequent-Restriction-Site Amplification (IRS PCR), double digestion Ligation Mediated Suppression PCR (ddLMS PCR). These techniques are now applied more and more often because they involve less time, are comparably inexpensive, and require only standard lab equipment. Here, we present a general review of this group of methods showing their possibilities and limitations. We also identify questions and propose solutions which may be helpful in choosing a particular LM PCR method for the achievement of the required goal.

  9. Torque expression in self-ligating orthodontic brackets and conventionally ligated brackets: A systematic review (United States)

    Al-Thomali, Yousef; Mohamed, Roshan-Noor; Basha, Sakeenabi


    Background To evaluate the torque expression of self ligating (SL) orthodontic brackets and conventionally ligated brackets and the torque expression in active and passive SL brackets. Material and Methods Our systematic search included MEDLINE, EMBASE, CINAHL, PsychINFO, Scopus, and key journals and review articles; the date of the last search was April 4th 2016. We graded the methodological quality of the studies by means of the Quality Assessment Tool for Quantitative Studies, developed for the Effective Public Health Practice Project (EPHPP). Results In total, 87 studies were identified for screening, and 9 studies were eligible. The quality assessment rated one of the study as being of strong quality, 7 (77.78%) of these studies as being of moderate quality. Three out of 7 studies which compared SL and conventionally ligated brackets showed, conventionally ligated brackets with highest torque expression compared to SL brackets. Badawi showed active SL brackets with highest torque expression compared to passive SL brackets. Major and Brauchli showed no significant differences in torque expression of active and passive SL brackets. Conclusions Conventionally ligated brackets presented with highest torque expression compared to SL brackets. Minor difference was recorded in a torque expression of active and passive SL brackets. Key words:Systematic review, self ligation, torque expression, conventional ligation. PMID:28149476

  10. Increasing the efficiency of SAGE adaptor ligation by directed ligation chemistry (United States)

    So, Austin P.; Turner, Robin F. B.; Haynes, Charles A.


    The ability of Serial Analysis of Gene Expression (SAGE) to provide a quantitative picture of global gene expression relies not only on the depth and accuracy of sequencing into the SAGE library, but also on the efficiency of each step required to generate the SAGE library from the starting mRNA material. The first critical step is the ligation of adaptors containing a Type IIS recognition sequence to the anchored 3′ end cDNA population that permits the release of short sequence tags (SSTs) from defined sites within the 3′ end of each transcript. Using an in vitro transcript as a template, we observed that only a small fraction of anchored 3′ end cDNA are successfully ligated with added SAGE adaptors under typical reaction conditions currently used in the SAGE protocol. Although the introduction of ∼500-fold molar excess of adaptor or the inclusion of 15% (w/v) PEG-8000 increased the yield of the adaptor-modified product, complete conversion to the desired adaptor:cDNA hetero-ligation product is not achieved. An alternative method of ligation, termed as directed ligation, is described which exploits a favourable mass-action condition created by the presence of NlaIII during ligation in combination with a novel SAGE adaptor containing a methylated base within the ligation site. Using this strategy, we were able to achieve near complete conversion of the anchored 3′ end cDNA into the desired adaptor-modified product. This new protocol therefore greatly increases the probability that a SST will be generated from every transcript, greatly enhancing the fidelity of SAGE. Directed ligation also provides a powerful means to achieve near-complete ligation of any appropriately designed adaptor to its respective target. PMID:15247329

  11. Post tubal ligation syndrome or iatrogenic hydrosalpinx. (United States)

    Gregory, M G


    The purpose of this case report is as follows: to attempt to establish an association between the observed increase in hydrosalpinx and the phenomenal increase in surgical sterilization; to present a credible etiology for iatrogenic hydrosalpinx; and to discuss the pathogenesis of a disease process henceforth referred to as post tubal ligation syndrome. A 36-year-old white woman was admitted to Park View Hospital in Nashville, Tennessee on January 7, 1981 for evaluation of continuous lower abdominal pain, abdominal pressure, and dyspareunia for several months. The woman had 2 children who were delivered vaginally. An abdominal tubal ligation was performed for sterilization when she was 27, and vaginal hysterectomy, with anterior and posterior colporrhaphy, was done for symptomatic pelvic relaxation at age 33. Physical examination showed tenderness without palpable masses in the pelvic adnexal areas. Laboratory studies were within normal limits. On January 9, 1981, the patient underwent exploratory laparotomy, and bilateral salpingo-oophorectomy. She was found to have bilateral hydrosalpinx. Historically, hydrosalpinx has been considered an intermediary step in pelvic inflammatory disease. Iatrogenic hydrosalpinx is, in essence, initiated by an initial insult, e.g., tubal ligation, fulguration, or application of a mechanical clip or band. Theoretically, single point interruption of a fallopian tube should produce no ill effects. The popularity and success of tubal ligation attest to single point interruption of an otherwise normal fallopian tube as an innocuous procedure. A schematic drawing is provided of the same tube insulted a 2nd time and consequently the situation is prefactory to development of hydrosalpinx, i.e., a tube lined with secretory epithelium is closed at both ends. Secretion within this closed system will produce dilatation. This "2nd" insult to the normal fallopian tube, post tubal ligation, may take 1 of several forms. The symptoms of iatrogenic

  12. A comparative study of Barron's rubber band ligation with Kshar Sutra ligation in hemorrhoids



    Despite a long medical history of identification and treatment, hemorrhoids still pose a challenge to the medical fraternity in terms of finding satisfactory cure of the disease. In this study, Kshar Sutra Ligation (KSL), a modality of treatment described in Ayurveda, was compared with Barron's Rubber Band Ligation (RBL) for grade II and grade III hemorrhoids. This study was conducted in 20 adult patients of either sex with grade II and grade III hemorrhoids at two different hospitals. Patien...

  13. Wireless Josephson amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Narla, A.; Sliwa, K. M.; Hatridge, M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H. [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States)


    Josephson junction parametric amplifiers are playing a crucial role in the readout chain in superconducting quantum information experiments. However, their integration with current 3D cavity implementations poses the problem of transitioning between waveguide, coax cables, and planar circuits. Moreover, Josephson amplifiers require auxiliary microwave components, like directional couplers and/or hybrids, that are sources of spurious losses and impedance mismatches that limit measurement efficiency and amplifier tunability. We have developed a wireless architecture for these parametric amplifiers that eliminates superfluous microwave components and interconnects. This greatly simplifies their assembly and integration into experiments. We present an experimental realization of such a device operating in the 9–11 GHz band with about 100 MHz of amplitude gain-bandwidth product, on par with devices mounted in conventional sample holders. The simpler impedance environment presented to the amplifier also results in increased amplifier tunability.

  14. Oscillators and operational amplifiers

    DEFF Research Database (Denmark)

    Lindberg, Erik


    A generalized approach to the design of oscillators using operational amplifiers as active elements is presented. A piecewise-linear model of the amplifier is used so that it make sense to investigate the eigenvalues of the Jacobian of the differential equations. The characteristic equation...... of the general circuit is derived. The dynamic nonlinear transfer characteristic of the amplifier is investigated. Examples of negative resistance oscillators are discussed....

  15. Cost saving by reloading the multiband ligator in endoscopic esophageal variceal ligation: A proposal for developing countries

    Institute of Scientific and Technical Information of China (English)

    Zaigham Abbas; Lubna Rizvi; Umair Syed Ahmed; Khalid Mumtaz; Wasim Jafri


    AIM: To assess the cost savings of reloading the multiband ligator in endoscopic esophageal variceal ligation (EVL) used on the same patient for subsequent sessions,METHODS: This single centre retrospective descriptive study analysed patients undergoing variceal ligation at a tertiary care centre between 1st January, 2003 and 30th June, 2006. The multiband ligator was reloaded with six hemorrhoidal bands using hemorrhoidal ligator for the second and subsequent sessions. Analysis of cost saving was done for the number of follow-up sessions for the variceal eradication.RESULTS: A total of 261 patients underwent at least one session of endoscopic esophageal variceal ligation between January 2003 and June 2006. Out of 261, 108 patients (males 67) agreed to follow the eradication program and underwent repeated sessions. A total of 304 sessions was performed with 2.81 sessions per patient on average. Thirty-two patients could not complete the programm. In 76 patients (70%), variceal obliteration was achieved. The ratio of the costs for the session with reloaded ligator versus a session with a new ligator was 1:2.37. Among the patients who completed esophageal varices eradication, cost saving with reloaded ligator was 58%.CONCLUSION: EVL using reloaded multiband ligators for the follow-up sessions on patients undergoing variceal eradication is a cost saving procedure. Reloading the ligator thus is recommended especially for developing countries where most of the patients are not health insured.

  16. Testing the feasibility of DNA typing for human identification by PCR and an oligonucleotide ligation assay

    Energy Technology Data Exchange (ETDEWEB)

    Delahunty, C.; Ankener, W.; Deng, Qiang [Univ. of Washington, Seattle, WA (United States)] [and others


    The use of DNA typing in human genome analysis is increasing and finding widespread application in the area of forensic and paternity testing. In this report, we explore the feasibility of typing single nucleotide polymorphisms (SNPs) by using a semiautomated method for analyzing human DNA samples. In this approach, PCR is used to amplify segments of human DNA containing a common SNP. Allelic nucleotides in the amplified product are then typed by a calorimetric implementation of the oligonucleotide ligation assay (OLA). The results of the combined assay, PCR/OLA, are read directly by a spectrophotometer; the absorbances are compiled and the genotypes are automatically determined. A panel of 20 markers has been developed for DNA typing and has been tested using a sample panel from the CEPH pedigrees (CEPH parents). The results of this typing, as well as the potential to apply this method to larger populations, are discussed. 62 refs., 2 figs., 4 tabs.

  17. Usefulness of ligation-mediated PCR genotyping in tracking outbreak-associated Mycobacterium tuberculosis strains. (United States)

    Mardassi, H; Namouchi, A; Karbouli, A; Khabouchi, N; Haltiti, R; Zarrouk, M; Mhennii, B; Kaabi, S


    With the emergence of a multidrug resistant tuberculosis (MDR-TB) outbreak, the availability of a rapid typing method to carry out a nationwide prospective survey for the tracking of newly emerging MDR-TB foci became a priority. For this purpose, we have applied the IS6110 PCR-based genotyping assay, namely, LM-PCR (ligation-mediated PCR). The latter relies on ligation of a synthetic oligonucleotide priming site to a restriction site flanking IS6110. Sequences between the IS element and the restriction site are then amplified using an IS6110 specific outward primer and an oligonucleotide specific to the ligated priming site. Although it was found slightly less discriminative than the standard IS6110 restriction fragment length polymorphism analysis (IS6110 RFLP), LM-PCR allowed for the rapid and prospective identification of new outbreak-related cases within a large pool of circulating M. tuberculosis isolates. In comparison to IS6110 RFLP LM-PCR was found simple enough to justify its implementation in laboratories involved in MDR-TB surveillance at a nationwide scale.

  18. Surface ligation-based resonance light scattering analysis of methylated genomic DNA on a microarray platform. (United States)

    Ma, Lan; Lei, Zhen; Liu, Xia; Liu, Dianjun; Wang, Zhenxin


    DNA methylation is a crucial epigenetic modification and is closely related to tumorigenesis. Herein, a surface ligation-based high throughput method combined with bisulfite treatment is developed for analysis of methylated genomic DNA. In this method, a DNA microarray is employed as a reaction platform, and resonance light scattering (RLS) of nanoparticles is used as the detection principle. The specificity stems from allele-specific ligation of Taq DNA ligase, which is further enhanced by improving the fidelity of Taq DNA ligase in a heterogeneous reaction. Two amplification techniques, rolling circle amplification (RCA) and silver enhancement, are employed after the ligation reaction and a gold nanoparticle (GNP) labeling procedure is used to amplify the signal. As little as 0.01% methylated DNA (i.e. 2 pmol L(-1)) can be distinguished from the cocktail of methylated and unmethylated DNA by the proposed method. More importantly, this method shows good accuracy and sensitivity in profiling the methylation level of genomic DNA of three selected colonic cancer cell lines. This strategy provides a high throughput alternative with reasonable sensitivity and resolution for cancer study and diagnosis.

  19. Optoisolators simplify amplifier design (United States)

    Ting, Joseph Wee


    Simplicity and low parts count are key virtues to this high voltage amplifier. Optoisolators replace complex high voltage transistor biasing schemes. This amplifier employs only 2 optoisolators, 16 high voltage mosfets transistors, 2 low voltage ones, 6 linear IC's and a score of passive components. Yet it can amplify opamp signals to 5 kV peak-to-peak from DC to sine waves up to 20 kHz. Resistor feedback guarantees the fidelity of the signal. It can source and sink 10 mA of output current. This amplifier was conceived to power ion traps for biological whole cell mass measurements. It is a versatile tool for a variety of applications.

  20. RF Power Amplifier Analysis

    Directory of Open Access Journals (Sweden)

    M. Lokay


    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.

  1. Charge-sensitive amplifier

    Directory of Open Access Journals (Sweden)

    Startsev V. I.


    Full Text Available 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.

  2. Staudinger Ligation of Peptides at Non-Glycyl Residues


    Soellner, Matthew B.; Tam, Annie; Raines, Ronald T.


    The Staudinger ligation provides a means to form an amide bond between a phosphinothioester and azide. This reaction holds promise for the ligation of peptides en route to the total chemical synthesis of proteins. (Diphenylphosphino)methanethiol is the most efficacious of known reagents for mediating the Staudinger ligation of peptides, providing high (>90%) isolated yields for equimolar couplings in which a glycine residue is at the nascent junction. Surprisingly, the yields are lower (80%) ...

  3. The HubBLe trial: haemorrhoidal artery ligation (HAL versus rubber band ligation (RBL for haemorrhoids

    Directory of Open Access Journals (Sweden)

    Tiernan Jim


    Full Text Available Abstract Background Haemorrhoids (piles are a very common condition seen in surgical clinics. After exclusion of more sinister causes of haemorrhoidal symptoms (rectal bleeding, perianal irritation and prolapse, the best option for treatment depends upon persistence and severity of the symptoms. Minor symptoms often respond to conservative treatment such as dietary fibre and reassurance. For more severe symptoms treatment such as rubber band ligation may be therapeutic and is a very commonly performed procedure in the surgical outpatient setting. Surgery is usually reserved for those who have more severe symptoms, as well as those who do not respond to non-operative therapy; surgical techniques include haemorrhoidectomy and haemorrhoidopexy. More recently, haemorrhoidal artery ligation has been introduced as a minimally invasive, non destructive surgical option. There are substantial data in the literature concerning efficacy and safety of 'rubber band ligation including multiple comparisons with other interventions, though there are no studies comparing it to haemorrhoidal artery ligation. A recent overview has been carried out by the National Institute for Health and Clinical Excellence which concludes that current evidence shows haemorrhoidal artery ligation to be a safe alternative to haemorrhoidectomy and haemorrhoidopexy though it also highlights the lack of good quality data as evidence for the advantages of the technique. Methods/design The aim of this study is to establish the clinical effectiveness and cost effectiveness of haemorrhoidal artery ligation compared with conventional rubber band ligation in the treatment of people with symptomatic second or third degree (Grade II or Grade III haemorrhoids. Design: A multi-centre, parallel group randomised controlled trial. Outcomes: The primary outcome is patient-reported symptom recurrence twelve months following the intervention. Secondary outcome measures relate to symptoms

  4. Amplified-fragment length polymorphism fingerprinting of Mycoplasma species

    DEFF Research Database (Denmark)

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


    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...

  5. Efficient in situ detection of mRNAs using the Chlorella virus DNA ligase for padlock probe ligation. (United States)

    Schneider, Nils; Meier, Matthias


    Padlock probes are single-stranded DNA molecules that are circularized upon hybridization to their target sequence by a DNA ligase. In the following, the circulated padlock probes are amplified and detected with fluorescently labeled probes complementary to the amplification product. The hallmark of padlock probe assays is a high detection specificity gained by the ligation reaction. Concomitantly, the ligation reaction is the largest drawback for a quantitative in situ detection of mRNAs due to the low affinities of common DNA or RNA ligases to RNA-DNA duplex strands. Therefore, current protocols require that mRNAs be reverse transcribed to DNA before detection with padlock probes. Recently, it was found that the DNA ligase from Paramecium bursaria Chlorella virus 1 (PBCV-1) is able to efficiently ligate RNA-splinted DNA. Hence, we designed a padlock probe assay for direct in situ detection of mRNAs using the PBCV-1 DNA ligase. Experimental single-cell data were used to optimize and characterize the efficiency of mRNA detection with padlock probes. Our results demonstrate that the PBCV-1 DNA ligase overcomes the efficiency limitation of current protocols for direct in situ mRNA detection, making the PBCV-1 DNA ligase an attractive tool to simplify in situ ligation sequencing applications.

  6. Streamlined expressed protein ligation using split inteins. (United States)

    Vila-Perelló, Miquel; Liu, Zhihua; Shah, Neel H; Willis, John A; Idoyaga, Juliana; Muir, Tom W


    Chemically modified proteins are invaluable tools for studying the molecular details of biological processes, and they also hold great potential as new therapeutic agents. Several methods have been developed for the site-specific modification of proteins, one of the most widely used being expressed protein ligation (EPL) in which a recombinant α-thioester is ligated to an N-terminal Cys-containing peptide. Despite the widespread use of EPL, the generation and isolation of the required recombinant protein α-thioesters remain challenging. We describe here a new method for the preparation and purification of recombinant protein α-thioesters using engineered versions of naturally split DnaE inteins. This family of autoprocessing enzymes is closely related to the inteins currently used for protein α-thioester generation, but they feature faster kinetics and are split into two inactive polypeptides that need to associate to become active. Taking advantage of the strong affinity between the two split intein fragments, we devised a streamlined procedure for the purification and generation of protein α-thioesters from cell lysates and applied this strategy for the semisynthesis of a variety of proteins including an acetylated histone and a site-specifically modified monoclonal antibody.

  7. Electrospun amplified fiber optics. (United States)

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


    All-optical signal processing is the focus of much research 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 efficient signal transmission. However, the complex fabrication methods involving high-temperature processes performed in a highly pure environment slow the fabrication process and make amplified components expensive with respect to an ideal, high-throughput, room temperature production. Here, we report on near-infrared polymer fiber amplifiers working over a band of ∼20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and shown to have amplified spontaneous emission with good gain coefficients and low levels of optical losses (a few cm(-1)). The amplification process is favored by high fiber quality and low self-absorption. The found performance metrics appear to be suitable for short-distance operations, and the large variety of commercially available doping dyes might allow for effective multiwavelength operations by electrospun amplified fiber optics.

  8. Tubal ligation and risk of ovarian cancer subtypes

    DEFF Research Database (Denmark)

    Sieh, Weiva; Salvador, Shannon; McGuire, Valerie;


    Tubal ligation is a protective factor for ovarian cancer, but it is unknown whether this protection extends to all invasive histological subtypes or borderline tumors. We undertook an international collaborative study to examine the association between tubal ligation and ovarian cancer subtypes....

  9. A simple ligation-based method to increase the information density in sequencing reactions used to deconvolute nucleic acid selections (United States)

    Childs-Disney, Jessica L.; Disney, Matthew D.


    Herein, a method is described to increase the information density of sequencing experiments used to deconvolute nucleic acid selections. The method is facile and should be applicable to any selection experiment. A critical feature of this method is the use of biotinylated primers to amplify and encode a BamHI restriction site on both ends of a PCR product. After amplification, the PCR reaction is captured onto streptavidin resin, washed, and digested directly on the resin. Resin-based digestion affords clean product that is devoid of partially digested products and unincorporated PCR primers. The product's complementary ends are annealed and ligated together with T4 DNA ligase. Analysis of ligation products shows formation of concatemers of different length and little detectable monomer. Sequencing results produced data that routinely contained three to four copies of the library. This method allows for more efficient formulation of structure-activity relationships since multiple active sequences are identified from a single clone. PMID:18065718

  10. A new 10-min ligation method using a modified buffer system with a very low amount of T4 DNA ligase: the "Coffee Break Ligation" technique. (United States)

    Yoshino, Yuki; Ishida, Masaharu; Horii, Akira


    The ligation reaction is widely used in molecular biology. There are several kits available that complete the ligation reaction very rapidly but they are rather expensive. In this study, we successfully modified the ligation buffer with much lower cost than existing kits. The ligation reaction can be completed in 10 min using very low activities such as 0.01 U T4 DNA ligase, and costs only $1 for 100 reactions of 20 microl scale. We name this ligation system the "Coffee Break Ligation" system; one can complete ligation reaction while drinking a cup of coffee, and perform 100 reactions by spending money equivalent to a cup of coffee.

  11. Irreversible sortase A-mediated ligation driven by diketopiperazine formation. (United States)

    Liu, Fa; Luo, Ethan Y; Flora, David B; Mezo, Adam R


    Sortase A (SrtA)-mediated ligation has emerged as an attractive tool in bioorganic chemistry attributing to the remarkable specificity of the ligation reaction and the physiological reaction conditions. However, the reversible nature of this reaction limits the efficiency of the ligation reaction and has become a significant constraint to its more widespread use. We report herein a novel set of SrtA substrates (LPETGG-isoacyl-Ser and LPETGG-isoacyl-Hse) that can be irreversibly ligated to N-terminal Gly-containing moieties via the deactivation of the SrtA-excised peptide fragment through diketopiperazine (DKP) formation. The convenience of the synthetic procedure and the stability of the substrates in the ligation buffer suggest that both LPETGG-isoacyl-Ser and LPETGG-isoacyl-Hse are valuable alternatives to existing irreversible SrtA substrate sequences.

  12. Fourier plane image amplifier (United States)

    Hackel, L.A.; Hermann, M.R.; Dane, C.B.; Tiszauer, D.H.


    A solid state laser is frequency tripled to 0.3 {micro}m. A small portion of the laser is split off and generates a Stokes seed in a low power oscillator. The low power output passes through a mask with the appropriate hole pattern. Meanwhile, the bulk of the laser output is focused into a larger stimulated Brillouin scattering (SBS) amplifier. The low power beam is directed through the same cell in the opposite direction. The majority of the amplification takes place at the focus which is the fourier transform plane of the mask image. The small holes occupy large area at the focus and thus are preferentially amplified. The amplified output is now imaged onto the multichip module where the holes are drilled. Because of the fourier plane amplifier, only about 1/10th the power of a competitive system is needed. This concept allows less expensive masks to be used in the process and requires much less laser power. 1 fig.

  13. Fourier plane image amplifier (United States)

    Hackel, Lloyd A.; Hermann, Mark R.; Dane, C. Brent; Tiszauer, Detlev H.


    A solid state laser is frequency tripled to 0.3 .mu.m. A small portion of the laser is split off and generates a Stokes seed in a low power oscillator. The low power output passes through a mask with the appropriate hole pattern. Meanwhile, the bulk of the laser output is focused into a larger stimulated Brillouin scattering (SBS) amplifier. The low power beam is directed through the same cell in the opposite direction. The majority of the amplification takes place at the focus which is the fourier transform plane of the mask image. The small holes occupy large area at the focus and thus are preferentially amplified. The amplified output is now imaged onto the multichip module where the holes are drilled. Because of the fourier plane amplifier, only .about.1/10th the power of a competitive system is needed. This concept allows less expensive masks to be used in the process and requires much less laser power.

  14. Hexamine cobalt chloride promotes intermolecular ligation of blunt end DNA fragments by T4 DNA ligase.


    Rusche, J R; Howard-Flanders, P


    Hexamine cobalt chloride (HCC) increases the efficiency of blunt end ligation by T4 DNA ligase about 50 fold. Maximum stimulation occurs when standard buffers for ligation are supplemented with 1 mM HCC. All the ligation events are intermolecular regardless of the initial DNA concentration. In the presence of monovalent cations (eg. 25 mM KCl) HCC still increases the extent of T4 catalyzed ligation but intramolecular ligation products are also formed. Therefore, intermolecular ligation can be...

  15. Supported PCR: an efficient procedure to amplify sequences flanking a known DNA segment


    Rudenko, George N.; Rommens, Caius M.T.; Nijkamp, H. John J.; Hille, Jacques


    We describe a novel modification of the polymerase chain reaction for efficient in vitro amplification of genomic DNA sequences flanking short stretches of known sequence. The technique utilizes a target enrichment step, based on the selective isolation of biotinylated fragments from the bulk of genomic DNA on streptavidin-containing support. Subsequently, following ligation with a second universal linker primer, the selected fragments can be amplified to amounts suitable for further molecula...


    Noe, J.B.


    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)

  17. Convergent synthesis of proteins by kinetically controlled ligation (United States)

    Kent, Stephen; Pentelute, Brad; Bang, Duhee; Johnson, Erik; Durek, Thomas


    The present invention concerns methods and compositions for synthesizing a polypeptide using kinetically controlled reactions involving fragments of the polypeptide for a fully convergent process. In more specific embodiments, a ligation involves reacting a first peptide having a protected cysteyl group at its N-terminal and a phenylthioester at its C-terminal with a second peptide having a cysteine residue at its N-termini and a thioester at its C-termini to form a ligation product. Subsequent reactions may involve deprotecting the cysteyl group of the resulting ligation product and/or converting the thioester into a thiophenylester.

  18. Polarization effect in parametric amplifier

    Institute of Scientific and Technical Information of China (English)

    Junhe Zhou; Jianping Chen; Xinwan Li; Guiling Wu; Yiping Wang


    @@ Polarization effect in parametric amplifiers is studied. Coupled equations are derived from the basic propagation equations and numerical solutions are given for both one-wavelength-pump and two-wavelengthpump systems. Several parametric amplifiers driven by pumps at one wavelength and two wavelengths are analyzed and the polarization independent parametric amplifier is proposed.

  19. Radio Frequency Solid State Amplifiers

    CERN Document Server

    Jacob, J


    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.

  20. Multiple pass laser amplifier system (United States)

    Brueckner, Keith A.; Jorna, Siebe; Moncur, N. Kent


    A laser amplification method for increasing the energy extraction efficiency from laser amplifiers while reducing the energy flux that passes through a flux limited system which includes apparatus for decomposing a linearly polarized light beam into multiple components, passing the components through an amplifier in delayed time sequence and recombining the amplified components into an in phase linearly polarized beam.

  1. Formatting and ligating biopolymers using adjustable nanoconfinement (United States)

    Berard, Daniel J.; Shayegan, Marjan; Michaud, Francois; Henkin, Gil; Scott, Shane; Leslie, Sabrina


    Sensitive visualization and conformational control of long, delicate biopolymers present critical challenges to emerging biotechnologies and biophysical studies. Next-generation nanofluidic manipulation platforms strive to maintain the structural integrity of genomic DNA prior to analysis but can face challenges in device clogging, molecular breakage, and single-label detection. We address these challenges by integrating the Convex Lens-induced Confinement (CLiC) technique with a suite of nanotopographies embedded within thin-glass nanofluidic chambers. We gently load DNA polymers into open-face nanogrooves in linear, concentric circular, and ring array formats and perform imaging with single-fluorophore sensitivity. We use ring-shaped nanogrooves to access and visualize confinement-enhanced self-ligation of long DNA polymers. We use concentric circular nanogrooves to enable hour-long observations of polymers at constant confinement in a geometry which eliminates the confinement gradient which causes drift and can alter molecular conformations and interactions. Taken together, this work opens doors to myriad biophysical studies and biotechnologies which operate on the nanoscale.

  2. A comparative study of Barron's rubber band ligation with Kshar Sutra ligation in hemorrhoids (United States)

    Singh, Rakhi; Arya, Ramesh C.; Minhas, Satinder S.; Dutt, Anil


    Despite a long medical history of identification and treatment, hemorrhoids still pose a challenge to the medical fraternity in terms of finding satisfactory cure of the disease. In this study, Kshar Sutra Ligation (KSL), a modality of treatment described in Ayurveda, was compared with Barron's Rubber Band Ligation (RBL) for grade II and grade III hemorrhoids. This study was conducted in 20 adult patients of either sex with grade II and grade III hemorrhoids at two different hospitals. Patients were randomly allotted to two groups of 10 patients each. Group I patients underwent RBL, whereas patients of group II underwent KSL. Guggul-based Apamarga Kshar Sutra was prepared according to the principles laid down in ancient Ayurvedic texts and methodology standardized by IIIM, Jammu and CDRI, Lucknow. Comparative assessment of RBL and KSL was done according to 16 criteria. Although the two procedures were compared on 15 criteria, treatment outcome of grade II and grade III hemorrhoids was decided chiefly on the basis of patient satisfaction index (subjective criterion) and ability of each procedure to deal with prolapse of internal hemorrhoidal masses (objective criterion): Findings in each case were recorded over a follow-up of four weeks (postoperative days 1, 3, 7, 15 and 30). Statistical analysis was done using Student's t test for parametric data and Chi square test & Mann-Whitney test for non-parametric data. P 0.05). Both the groups were comparable statistically on all other grounds. Kshar Sutra Ligation is a useful form of treatment for Grades II and III internal hemorrhoids. PMID:20814519

  3. A Photo-Triggered Traceless Staudinger-Bertozzi Ligation Reaction. (United States)

    Hu, Peng; Feng, Tianshi; Yeung, Chi-Chung; Koo, Chi-Kin; Lau, Kai-Chung; Lam, Michael H W


    The use of light to control the course of a chemical/biochemical reaction is an attractive idea because of its ease of administration with high precision and fine spatial resolution. Staudinger ligation is one of the commonly adopted conjugation processes that involve a spontaneous reaction between azides and arylphosphines to form iminophosphoranes, which further hydrolyze to give stable amides. We designed an anthracenylmethyl diphenylphosphinothioester (1) that showed promising Staudinger ligation reactivity upon photo-excitation. Broadband photolysis at 360-400 nm in aqueous organic solvents induced heterolytic cleavage of its anthracenylmethyl-phosphorus bond, releasing a diphenylphosphinothioester (2) as an efficient traceless Staudinger-Bertozzi ligation reagent. The quantum yield of such a photo-induced heterolytic bond-cleavage at the optimal wavelength of photolysis (376 nm) at room temperature is ≥0.07. This work demonstrated the feasibility of photocaging arylphosphines to realize the photo-triggering of the Staudinger ligation reaction.

  4. Simplified design of IC amplifiers

    CERN Document Server

    Lenk, John


    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

  5. Electronic amplifiers for automatic compensators

    CERN Document Server

    Polonnikov, D Ye


    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

  6. RNA-templated DNA ligation for transcript analysis


    Nilsson, Mats; Antson, Dan-Oscar; Barbany, Gisela; Landegren, Ulf


    Ligase-mediated gene detection has proven valuable for detection and precise distinction of DNA sequence variants. We have recently shown that T4 DNA ligase can also be used to distinguish single nucleotide variants of RNA sequences. Here we describe parameters that influence RNA-templated DNA ligation by T4 DNA ligase. The reaction proceeds much more slowly, requiring more enzyme, compared to ligation of the same oligonucleotides hybridized to the corresponding DNA se...

  7. Building valve amplifiers

    CERN Document Server

    Jones, Morgan


    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


    Kabell, L.J.


    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.

  9. Wideband amplifier design

    CERN Document Server

    Hollister, Allen L


    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

  10. Intramyocardial activation in early ventricular arrhythmias following coronary artery ligation. (United States)

    Kaplinsky, E; Ogawa, S; Kmetzo, J; Balke, C W; Dreifus, L S


    Subendocardial, subepicardial and intramyocardial activation in the ischemic zone was investigated in 20 anesthetized open chest dogs 0-30 minutes after the ligation of the left anterior descending coronary artery. Single and composite electrograms and lead 2 of the ECG were recorded. Coronary artery ligation produced marked delay, fragmentation, and reduction in amplitude in the electrical activity of the subepicardial and intramyocardial muscle layers. The activation remained synchronous in the subendocardial muscle layers. Extension of electrical activity in the ischemic subepicardium and intramyocardium beyond the T wave of the surface ECG preceded the onset of immediate ventricular arrhythmias (IVA) during the initial ten minute period after coronary artery ligation. However, a second surge of delayed ventricular arrhythmias (DVA), 10-30 minutes after ligation, was not associated with the appearance of diastolic electrical activity in any of the subepicardial or myocardial layers. It appears that subepicardial as well as intramyocardial reentry could play an important role in the genesis of the immediate ventricular arrhythmias (1-10 minutes after ligation). In contrast, no obvious reentrant activity as evidenced by delayed and fragmented electrical activity could be observed in the electrogram from any of the myocardial electrical activity could be observed in the electrogram from any of the myocardial layers with the appearance of delayed ventricular ectopic activity 10-30 minutes after ligation.

  11. Rubber band ligation of hemorrhoids: A guide for complications (United States)

    Albuquerque, Andreia


    Rubber band ligation is one of the most important, cost-effective and commonly used treatments for internal hemorrhoids. Different technical approaches were developed mainly to improve efficacy and safety. The technique can be employed using an endoscope with forward-view or retroflexion or without an endoscope, using a suction elastic band ligator or a forceps ligator. Single or multiple ligations can be performed in a single session. Local anaesthetic after ligation can also be used to reduce the post-procedure pain. Mild bleeding, pain, vaso-vagal symptoms, slippage of bands, priapism, difficulty in urination, anal fissure, and chronic longitudinal ulcers are normally considered minor complications, more frequently encountered. Massive bleeding, thrombosed hemorrhoids, severe pain, urinary retention needing catheterization, pelvic sepsis and death are uncommon major complications. Mild pain after rubber band ligation is the most common complication with a high frequency in some studies. Secondary bleeding normally occurs 10 to 14 d after banding and patients taking anti-platelet and/or anti-coagulant medication have a higher risk, with some reports of massive life-threatening haemorrhage. Several infectious complications have also been reported including pelvic sepsis, Fournier’s gangrene, liver abscesses, tetanus and bacterial endocarditis. To date, seven deaths due to these infectious complications were described. Early recognition and immediate treatment of complications are fundamental for a favourable prognosis. PMID:27721924

  12. Mechanism of Imidazole-Promoted Ligation of Peptide Phenyl Esters

    Institute of Scientific and Technical Information of China (English)

    王晨; 刘磊


    Imidazole-promoted ligation of peptide phenyl esters was recently found to be a complementary method for protein chemical synthesis. Theoretical calculations have been carried out to understand the detailed mechanism of this particular ligation process. It is found that both the reaction of the phenyl ester with imidazole and the reaction of the acyl imidazole intermediate with cysteine proceed through an addition-elimination mechanism. The cleavage of the C--O bond in the reaction between the phenyl ester and imidazole is the rate-limiting step of the overall liga- tion process. Interestingly, although the imidazole-promoted phenyl ester ligation has a higher free energy barrier than the conventional thiophenol-promoted native chemical ligation for a sterically less hindered C-terminal amino acid (e.g. gylcine), for a sterically hindered C-terminal amino acid (e.g. proline) the imidazole-promoted phenyl ester ligation is calculated to be more favorable than the conventional thiophenol-promoted native chemical ligation.


    Directory of Open Access Journals (Sweden)



    Full Text Available AIMS AND OBJECTIVE Bilateral internal iliac artery ligation is a useful skill for the management of life-threatening post-partum hemorrhage. The procedure is not without risks and long-term complications. This study was conducted to ensure documentation and reporting of pregnancies following bilateral hypogastric artery ligation in cases of post-partum hemorrhage. We also aimed to compare the menstrual function and reproductive outcome after bilateral internal iliac artery ligation done for atonic post-partum haemorrhage. DESIGN Prospective Case Study. SETTING Department of Obstetrics and Gynaecology, Institute of Obstetrics and Gynaecology, Madras Medical College and Hospital, Chennai, Jan 2013 to March 2015. PARTICIPANTS Ten cases of bilateral internal iliac artery ligation were done for atonic post-partum hemorrhage. Main outcome measures: The primary outcome was assessed as the resumption of menstruation, regular cycles, and ability to conceive after surgery. Secondary outcome was incidence of intrauterine growth retardation and recurrent post-partum hemorrhage in subsequent pregnancies. RESULTS The mean duration of resumption of menstruation following internal iliac artery ligation was 3 months. Bilateral internal iliac artery ligation is preferred over unilateral ligation as the extensive collaterals from the contralateral side immediately fill the circulation. The cases of atonic post-partum hemorrhage may require B-Lynch sutures in addition to bilateral internal iliac artery ligation to regain tone. Successful pregnancy after bilateral internal iliac artery ligation occurred in three out of seven cases. In one case, there was intrauterine growth retardation in eighth month. The patient was admitted and closely monitored with Doppler scan. At 35 weeks of gestation, emergency lower segment caesarean section was done for absent diastolic flow. The preterm neonate was 2 kilograms. There was no post-partum hemorrhage in the subsequent

  14. Nanoscale electromechanical parametric amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Aleman, Benjamin Jose; Zettl, Alexander


    This disclosure provides systems, methods, and apparatus related to a parametric amplifier. In one aspect, a device includes an electron source electrode, a counter electrode, and a pumping electrode. The electron source electrode may include a conductive base and a flexible conductor. The flexible conductor may have a first end and a second end, with the second end of the flexible conductor being coupled to the conductive base. A cross-sectional dimension of the flexible conductor may be less than about 100 nanometers. The counter electrode may be disposed proximate the first end of the flexible conductor and spaced a first distance from the first end of the flexible conductor. The pumping electrode may be disposed proximate a length of the flexible conductor and spaced a second distance from the flexible conductor.

  15. 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....

  16. Ligation-assisted endoscopic mucosal resection of gastric heterotopic pancreas

    Institute of Scientific and Technical Information of China (English)

    Mouen A Khashab; Oscar W Cummings; John M DeWitt


    Heterotopic pancreas is a congenital anomaly characterized by ectopic pancreatic tissue.Treatment of heterotopic pancreas may include expectant observation,endoscopic resection or surgery.The aim of this report was to describe the technique of ligation-assisted endoscopic mucosal resection (EMR) for resection of heterotopic pancreas of the stomach.Two patients (both female,mean age 32 years) were referred for management of gastric subepithelial tumors.Endoscopic ultrasound in both disclosed small hypoechoic masses in the mucosa and submucosa.Band ligation-assisted EMR was performed in both cases without complications.Pathology from the resected tumors revealed heterotopic pancreas arising from the submucosa.Margins were free of pancreatic tissue.Ligation-assisted EMR is technically feasible and may be considered for the endoscopic management of heterotopic pancreas.

  17. A Generic Polymer-Protein Ligation Strategy for Vaccine Delivery. (United States)

    Lybaert, Lien; Vanparijs, Nane; Fierens, Kaat; Schuijs, Martijn; Nuhn, Lutz; Lambrecht, Bart N; De Geest, Bruno G


    Although the field of cancer immunotherapy is intensively investigated, there is still a need for generic strategies that allow easy, mild and efficient formulation of vaccine antigens. Here we report on a generic polymer-protein ligation strategy to formulate protein antigens into reversible polymeric conjugates for enhanced uptake by dendritic cells and presentation to CD8 T-cells. A N-hydroxypropylmethacrylamide (HPMA)-based copolymer was synthesized via RAFT polymerization followed by introduction of pyridyldisulfide moieties. To enhance ligation efficiency to ovalbumin, which is used as a model protein antigen, protected thiols were introduced onto lysine residues and deprotected in situ in the presence of the polymer. The ligation efficiency was compared for both the thiol-modified versus unmodified ovalbumin, and the reversibility was confirmed. Furthermore, the obtained nanoconjugates were tested in vitro for their interaction and association with dendritic cells, showing enhanced cellular uptake and antigen cross-presentation to CD8 T-cells.

  18. Template-Directed Ligation of Peptides to Oligonucleotides (United States)

    Bruick, Richard K.; Dawson, Philip E.; Kent, Stephen BH; Usman, Nassim; Joyce, Gerald F.


    Synthetic oligonucleotides and peptides have enjoyed a wide range of applications in both biology and chemistry. As a consequence, oligonucleotide-peptide conjugates have received considerable attention, most notably in the development of antisense constructs with improved pharmacological properties. In addition, oligonucleotide-peptide conjugates have been used as molecular tags, in the assembly of supramolecular arrays and in the construction of encoded combinatorial libraries. To make these chimeric molecules more accessible for a broad range of investigations, we sought to develop a facile method for joining fully deprotected oligonucleotides and peptides through a stable amide bond linkage. Furthermore, we wished to make this ligation reaction addressable, enabling one to direct the ligation of specific oligonucleotide and peptide components.To confer specificity and accelerate the rate of the reaction, the ligation process was designed to be dependent on the presence of a complementary oligonucleotide template.

  19. Endocrine profile of patients with post-tubal-ligation syndrome. (United States)

    Hargrove, J T; Abraham, G E


    The endocrine profile of the midluteal phase was assessed in 29 patients with the post-tubal-ligation syndrome, consisting of pain, bleeding and premenstrual tension. Compared to normal controls, the patients had a high serum estradiol and a low serum progesterone level. This abnormal luteal function may be responsible for the symptoms observed and may also explain the failure to conceive following successful reversal of tubal ligation. It is recommended that patients seeking sterilization reversal be screened for abnormal luteal function preoperatively. Selection of sterilization procedures that minimize alteration in luteal function should be given high priority.

  20. Sequelae of tubal ligation: an analysis of 75 consecutive hysterectomies. (United States)

    Stock, R J


    Seventy-five consecutive patients undergoing hysterectomy subsequent to elective sterilization were studied regarding the occurrence of the post-tubal-ligation syndrome of pelvic pain and/or menorrhagia. Twenty patients were clinically considered to have the syndrome. In none of the patients operated on specifically for menstrual abnormalities could the findings be remotely attributed to the sterilization procedure. Five of the 20 patients had pelvic varicosities and one had pelvic adhesions that may have been a consequence of previous sterilization and conceivably the cause for the pelvic pain for which the patients were undergoing hysterectomy. I question the legitimacy of the post-tubal-ligation syndrome as a reason for hysterectomy.

  1. Alternative Okazaki Fragment Ligation Pathway by DNA Ligase III

    Directory of Open Access Journals (Sweden)

    Hiroshi Arakawa


    Full Text Available Higher eukaryotes have three types of DNA ligases: DNA ligase 1 (Lig1, DNA ligase 3 (Lig3 and DNA ligase 4 (Lig4. While Lig1 and Lig4 are present in all eukaryotes from yeast to human, Lig3 appears sporadically in evolution and is uniformly present only in vertebrates. In the classical, textbook view, Lig1 catalyzes Okazaki-fragment ligation at the DNA replication fork and the ligation steps of long-patch base-excision repair (BER, homologous recombination repair (HRR and nucleotide excision repair (NER. Lig4 is responsible for DNA ligation at DNA double strand breaks (DSBs by the classical, DNA-PKcs-dependent pathway of non-homologous end joining (C-NHEJ. Lig3 is implicated in a short-patch base excision repair (BER pathway, in single strand break repair in the nucleus, and in all ligation requirements of the DNA metabolism in mitochondria. In this scenario, Lig1 and Lig4 feature as the major DNA ligases serving the most essential ligation needs of the cell, while Lig3 serves in the cell nucleus only minor repair roles. Notably, recent systematic studies in the chicken B cell line, DT40, involving constitutive and conditional knockouts of all three DNA ligases individually, as well as of combinations thereof, demonstrate that the current view must be revised. Results demonstrate that Lig1 deficient cells proliferate efficiently. Even Lig1/Lig4 double knockout cells show long-term viability and proliferate actively, demonstrating that, at least in DT40, Lig3 can perform all ligation reactions of the cellular DNA metabolism as sole DNA ligase. Indeed, in the absence of Lig1, Lig3 can efficiently support semi-conservative DNA replication via an alternative Okazaki-fragment ligation pathway. In addition, Lig3 can back up NHEJ in the absence of Lig4, and can support NER and HRR in the absence of Lig1. Supporting observations are available in less elaborate genetic models in mouse cells. Collectively, these observations raise Lig3 from a niche

  2. Alternative Okazaki Fragment Ligation Pathway by DNA Ligase III. (United States)

    Arakawa, Hiroshi; Iliakis, George


    Higher eukaryotes have three types of DNA ligases: DNA ligase 1 (Lig1), DNA ligase 3 (Lig3) and DNA ligase 4 (Lig4). While Lig1 and Lig4 are present in all eukaryotes from yeast to human, Lig3 appears sporadically in evolution and is uniformly present only in vertebrates. In the classical, textbook view, Lig1 catalyzes Okazaki-fragment ligation at the DNA replication fork and the ligation steps of long-patch base-excision repair (BER), homologous recombination repair (HRR) and nucleotide excision repair (NER). Lig4 is responsible for DNA ligation at DNA double strand breaks (DSBs) by the classical, DNA-PKcs-dependent pathway of non-homologous end joining (C-NHEJ). Lig3 is implicated in a short-patch base excision repair (BER) pathway, in single strand break repair in the nucleus, and in all ligation requirements of the DNA metabolism in mitochondria. In this scenario, Lig1 and Lig4 feature as the major DNA ligases serving the most essential ligation needs of the cell, while Lig3 serves in the cell nucleus only minor repair roles. Notably, recent systematic studies in the chicken B cell line, DT40, involving constitutive and conditional knockouts of all three DNA ligases individually, as well as of combinations thereof, demonstrate that the current view must be revised. Results demonstrate that Lig1 deficient cells proliferate efficiently. Even Lig1/Lig4 double knockout cells show long-term viability and proliferate actively, demonstrating that, at least in DT40, Lig3 can perform all ligation reactions of the cellular DNA metabolism as sole DNA ligase. Indeed, in the absence of Lig1, Lig3 can efficiently support semi-conservative DNA replication via an alternative Okazaki-fragment ligation pathway. In addition, Lig3 can back up NHEJ in the absence of Lig4, and can support NER and HRR in the absence of Lig1. Supporting observations are available in less elaborate genetic models in mouse cells. Collectively, these observations raise Lig3 from a niche-ligase to a

  3. Pros and cons of patent ductus arteriosus ligation: hemodynamic changes and other morbidities after patent ductus arteriosus ligation. (United States)

    Noori, Shahab


    Although surgical ligation of a persistent patent ductus arteriosus resolves the adverse hemodynamic consequences of the systemic-to-pulmonary shunt and may confer some long-term benefits, it is also associated with both immediate and long-term negative effects. The population that benefits from or is harmed by the procedure is not clearly defined. Although indiscriminate ligation of the patent ductus arteriosus in all patients is not supported by the available information, the recent suggestion declaring the ductus harmless is not supported either. As we await the results of appropriately designed randomized control studies to define the indications for ligation, we must use clinical and echocardiographic indicators of a hemodynamically significant ductus arteriosus and thoughtful assessment of each individual patient to help guide us in addressing this complex problem.

  4. Sensitive detection of Aβ protofibrils by proximity ligation - relevance for Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Gustafsdottir Sigrun


    Full Text Available Abstract Background Protein aggregation plays important roles in several neurodegenerative disorders. For instance, insoluble aggregates of phosphorylated tau and of Aβ peptides are cornerstones in the pathology of Alzheimer's disease. Soluble protein aggregates are therefore potential diagnostic and prognostic biomarkers for their cognate disorders. Detection of the aggregated species requires sensitive tools that efficiently discriminate them from monomers of the same proteins. Here we have established a proximity ligation assay (PLA for specific and sensitive detection of Aβ protofibrils via simultaneous recognition of three identical determinants present in the aggregates. PLA is a versatile technology in which the requirement for multiple target recognitions is combined with the ability to translate signals from detected target molecules to amplifiable DNA strands, providing very high specificity and sensitivity. Results For specific detection of Aβ protofibrils we have used a monoclonal antibody, mAb158, selective for Aβ protofibrils in a modified PLA, where the same monoclonal antibody was used for the three classes of affinity reagents required in the assay. These reagents were used for detection of soluble Aβ aggregates in solid-phase reactions, allowing detection of just 0.1 pg/ml Aβ protofibrils, and with a dynamic range greater than six orders of magnitude. Compared to a sandwich ELISA setup of the same antibody the PLA increases the sensitivity of the Aβ protofibril detection by up to 25-fold. The assay was used to measure soluble Aβ aggregates in brain homogenates from mice transgenic for a human allele predisposing to Aβ aggregation. Conclusions The proximity ligation assay is a versatile analytical technology for proteins, which can provide highly sensitive and specific detection of Aβ aggregates - and by implication other protein aggregates of relevance in Alzheimer's disease and other neurodegenerative disorders.

  5. Detection of human papillomaviruses by polymerase chain reaction and ligation reaction on universal microarray.

    Directory of Open Access Journals (Sweden)

    Jarmo Ritari

    Full Text Available Sensitive and specific detection of human papillomaviruses (HPV in cervical samples is a useful tool for the early diagnosis of epithelial neoplasia and anogenital lesions. Recent studies support the feasibility of HPV DNA testing instead of cytology (Pap smear as a primary test in population screening for cervical cancer. This is likely to be an option in the near future in many countries, and it would increase the efficiency of screening for cervical abnormalities. We present here a microarray test for the detection and typing of 15 most important high-risk HPV types and two low risk types. The method is based on type specific multiplex PCR amplification of the L1 viral genomic region followed by ligation detection reaction where two specific ssDNA probes, one containing a fluorescent label and the other a flanking ZipCode sequence, are joined by enzymatic ligation in the presence of the correct HPV PCR product. Human beta-globin is amplified in the same reaction to control for sample quality and adequacy. The genotyping capacity of our approach was evaluated against Linear Array test using cervical samples collected in transport medium. Altogether 14 out of 15 valid samples (93% gave concordant results between our test and Linear Array. One sample was HPV56 positive in our test and high-risk positive in Hybrid Capture 2 but remained negative in Linear Array. The preliminary results suggest that our test has accurate multiple HPV genotyping capability with the additional advantages of generic detection format, and potential for high-throughput screening.

  6. Detection of human papillomaviruses by polymerase chain reaction and ligation reaction on universal microarray. (United States)

    Ritari, Jarmo; Hultman, Jenni; Fingerroos, Rita; Tarkkanen, Jussi; Pullat, Janne; Paulin, Lars; Kivi, Niina; Auvinen, Petri; Auvinen, Eeva


    Sensitive and specific detection of human papillomaviruses (HPV) in cervical samples is a useful tool for the early diagnosis of epithelial neoplasia and anogenital lesions. Recent studies support the feasibility of HPV DNA testing instead of cytology (Pap smear) as a primary test in population screening for cervical cancer. This is likely to be an option in the near future in many countries, and it would increase the efficiency of screening for cervical abnormalities. We present here a microarray test for the detection and typing of 15 most important high-risk HPV types and two low risk types. The method is based on type specific multiplex PCR amplification of the L1 viral genomic region followed by ligation detection reaction where two specific ssDNA probes, one containing a fluorescent label and the other a flanking ZipCode sequence, are joined by enzymatic ligation in the presence of the correct HPV PCR product. Human beta-globin is amplified in the same reaction to control for sample quality and adequacy. The genotyping capacity of our approach was evaluated against Linear Array test using cervical samples collected in transport medium. Altogether 14 out of 15 valid samples (93%) gave concordant results between our test and Linear Array. One sample was HPV56 positive in our test and high-risk positive in Hybrid Capture 2 but remained negative in Linear Array. The preliminary results suggest that our test has accurate multiple HPV genotyping capability with the additional advantages of generic detection format, and potential for high-throughput screening.

  7. Capacities of quantum amplifier channels (United States)

    Qi, Haoyu; Wilde, Mark M.


    Quantum amplifier channels are at the core of several physical processes. Not only do they model the optical process of spontaneous parametric down-conversion, but the transformation corresponding to an amplifier channel also describes the physics of the dynamical Casimir effect in superconducting circuits, the Unruh effect, and Hawking radiation. Here we study the communication capabilities of quantum amplifier channels. Invoking a recently established minimum output-entropy theorem for single-mode phase-insensitive Gaussian channels, we determine capacities of quantum-limited amplifier channels in three different scenarios. First, we establish the capacities of quantum-limited amplifier channels for one of the most general communication tasks, characterized by the trade-off between classical communication, quantum communication, and entanglement generation or consumption. Second, we establish capacities of quantum-limited amplifier channels for the trade-off between public classical communication, private classical communication, and secret key generation. Third, we determine the capacity region for a broadcast channel induced by the quantum-limited amplifier channel, and we also show that a fully quantum strategy outperforms those achieved by classical coherent-detection strategies. In all three scenarios, we find that the capacities significantly outperform communication rates achieved with a naive time-sharing strategy.

  8. Small signal microwave amplifier design

    CERN Document Server

    Grosch, Theodore


    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

  9. Sequence fidelity of a template-directed PNA-ligation reaction. (United States)

    Mattes, A; Seitz, O


    The ligation method and an appended duplex-stabilizing dye affect both yield and sequence selectivity of a template-controlled PNA-ligation. The highest selectivity was obtained with a peptide condensation that formed an abasic site.

  10. Assessment and treatment of post patent ductus arteriosus ligation syndrome.

    LENUS (Irish Health Repository)

    El-Khuffash, Afif F


    To compare differences in tissue Doppler imaging, global longitudinal strain (GLS), and cardiac troponin T (cTnT) between infants with low (<200 mL\\/kg\\/min) and high (>200 mL\\/kg\\/min) left ventricular (LV) output 1 hour after duct ligation and assess the impact of milrinone treatment on cardiac output and myocardial performance.

  11. Synthesis of coumarin or ferrocene labeled nucleosides via Staudinger ligation

    Directory of Open Access Journals (Sweden)

    Kois Pavol


    Full Text Available Abstract Background Reaction of azides with triaryl phosphines under mild conditions gives iminophosphoranes which can react with almost any kind of electrophilic reagent, e.g. aldehydes/ketones to form imines or esters to form amides. This so-called Staudinger ligation has been employed in a wide range of applications as a general tool for bioconjugation including specific labeling of nucleic acids. Results A new approach for the preparation of labeled nucleosides via intermolecular Staudinger ligation is described. Reaction of azidonucleosides with triphenylphosphine lead to iminophosphorane intermediates, which react subsequently with derivatives of coumarin or ferrocene to form coumarin or ferrocene labeled nucleosides. Fluorescent properties of coumarin labeled nucleosides are determined. Conclusion New coumarin and ferrocene labeled nucleosides were prepared via intermolecular Staudinger ligation. This reaction joins the fluorescent coumarin and biospecific nucleoside to the new molecule with promising fluorescent and electrochemical properties. The isolated yields of products depend on the structure of azidonucleoside and carboxylic acids. A detailed study of the kinetics of the Staudinger ligation with nucleoside substrates is in progress.

  12. Endoscopic banding ligation can effectively resect hyperplastic Polyps of stomach

    Institute of Scientific and Technical Information of China (English)

    Ching-Chu Lo; Wen-Chi Chen; E-Ming Wang; Kwok-Hung Lai; Ping-I Hsu; Gin-Ho Lo; Hui-Hwa Tseng; Hui-Chun Chen; Ping-Ning Hsu; Chiun-Ku Lin; Hoi-Hung Chan; Wei-Lun Tsai


    AIM: Bleeding and perforation are the major and serious complications associated with endoscopic polypectomy. To develop a safe and effective method to resect hyperplastic polyps of the stomach, we employed rubber bands to strangulate hyperplastic polyps and to determine the possibility of inducing avascular necrosis in these lesions.METHODS: Forty-seven patients with 72 hyperplastic polyps were treated with endoscopic banding ligation (EBL). On 14 days after endoscopic ligation, follow-up endoscopies were performed to assess the outcomes of the strangulated polyps.RESULTS: After being strangulated by the rubber bands,all of the polyps immediately became congested (100 %),and then developed cyanotic changes (100 %) approximately 4 minutes later. On follow-up endoscopy 2 weeks later, all the polyps except one had dropped off. The only one residual polyp shrank with a rubber band in its base, and it also dropped off spontaneously during subsequent follow-up.No complications occurred during or following the ligation procedures.CONCLUSION: Gastric polyps develop avascular necrosis following ligation by rubber bands. Employing suction equipment, EBL can easily capture sessile polyps. It is an easy, safe and effective method to eradicate hyperplastic polyps of the stomach.


    Directory of Open Access Journals (Sweden)

    Ramica Sharma et al.


    Full Text Available The study has been designed to investigate the effect of aqueous extract of rind of Punica granatum in sciatic nerve ligation induced-neuropathic pain in rats. Surgical procedure was performed with sciatic nerve ligation to develop neuropathic pain in rats. The development of neuropathic pain was assessed by employing behaviour parameters such as hyperalgesia and allodynia. Further, the functionality of sciatic nerve was assessed using the histopathological study of myelinated and unmyelinated fibers in sciatic nerve. Moreover, the oxidative stress was assessed by estimating serum thiobarbituric acid reactive substances (TBARS, catalase, glutathione and tissue TBARS and Superoxide dismutase (SOD. Rats exposed to sciatic nerve ligation produced marked increase in oxidative stress, which was assessed in terms of TBARS and SOD along with decrease in the level of catalase and glutathione. Moreover, it develops neuropathic pain by impairing the normal functions of myelinated and unmyelinated fibers in sciatic nerve. Treatment with aqueous extract of Punica granatum extract (100mg/kg, p.o markedly prevented sciatic nerve ligation-induced neuropathy and oxidative stress by increasing the pain threshold, by improving the functionality of sciatic nerve, by decreasing serum and tissue TBARS and tissue SOD, by increasing levels of serum glutathione and catalase. It may be concluded that Punica granatum extract reduced the oxidative stress via inhibiting p38MAPK and alleviates neuropathic symptoms and consequently improved the functionality of sciatic nerve and prevents sciatic nerve ligation–induced neuropathic pain.

  14. Adrenal function in preterm infants undergoing patent ductus arteriosus ligation.

    LENUS (Irish Health Repository)

    El-Khuffash, Afif


    Targeted milrinone treatment for low left ventricular output (LVO) reduces the incidence of acute cardiorespiratory instability following ligation of patent ductus arteriosus (PDA) in preterm infants. Despite this, some infants continue to experience postoperative deterioration. Adrenal insufficiency related to prematurity has been postulated as a possible mechanism.

  15. Ectopic pregnancy after two times tubal ligation: a case report

    Directory of Open Access Journals (Sweden)

    Farideh Keypour


    Full Text Available Background: Tubal sterilization is the permanent and effective contraception method. This can be performed at any time, but at least half are performed in conjunction with cesarean or vaginal delivery and are termed puerperal. The most complication after tubal ligation is ectopic pregnancy. Ectopic pregnancy is the leading cause of maternal death in first trimester.Case presentation: We present a 33 years old woman gravida5, para4, all normal vaginal delivery, presented with complaints of delayed menstrual period, pelvic pain and spotting. She underwent tubal ligation for two times. For the first time she had puerperal Pomeroy tubal sterilization after third child delivery. Intra uterine pregnancy occurred three years later. One day after vaginal delivery of fourth child, she underwent post partum tubal ligation with the Parkland method. Tubal pregnancy occurred nine months later. Physical examination identified acute abdomen. Pelvic ultrasound showed no gestational sac in uterine cavity. The sac with fetal pole was in right adnexa. Beta-HCG was 2840mIU/ml. She underwent laparotomy. Surgical management included salpingectomy with cornual resection in both sides. The surgery identified Ectopic pregnancy.Conclusion: Any symptoms of pregnancy in a woman after tubal ligation must be investigated; an ectopic pregnancy should be excluded. Ectopic pregnancy must be considered, in any woman with lower abdominal pain, missed period and vaginal bleed-ing. Conception after tubal sterilization can be explained by fistula formation and re-canalization of fallopian tube.

  16. Optimization of ligation reaction conditions in gene synthesis. (United States)

    Theriault, N Y; Carter, J B; Pulaski, S P


    Several phosphorylation, annealing and ligation reaction conditions have been investigated for the enzymatic assembly of genes of interest. The use of longer oligodeoxyribonucleotides (40-60 bases long) also improved the enzymatic reaction. Furthermore, the use of longer oligonucleotides and the elimination of long stretches of G's or C's lowered the mutation rate.

  17. Subfascial endoscopic ligation in the treatment of incompetent perforating veins

    NARCIS (Netherlands)

    E.G.J.M. Pierik; C.H. Wittens; H. van Urk (Hero)


    textabstractObjectives: To assess the technique of subfascial endoscopic ligation of incompetent perforatory veins by use of a mediastinoscope. Design: Prospective open clinic study. Setting: Two Departments of Surgery. Materials and Methods: Thirty-eight consecutive patients (40 legs) with recu

  18. International Standardization Activities for Optical Amplifiers

    Institute of Scientific and Technical Information of China (English)

    Haruo Okamura


    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.

  19. Corrosion behavior of self-ligating and conventional metal brackets

    Directory of Open Access Journals (Sweden)

    Lúcio Henrique Esmeraldo Gurgel Maia


    Full Text Available Objective: To test the null hypothesis that the aging process in self-ligating brackets is not higher than in conventional brackets. Methods: Twenty-five conventional (GN-3M/Unitek; GE-GAC; VE-Aditek and 25 self-ligating (SCs-3M/Unitek; INs-GAC; ECs-Aditek metal brackets from three manufacturers (n = 150 were submitted to aging process in 0.9% NaCl solution at a constant temperature of 37 ± 1ºC for 21 days. The content of nickel, chromium and iron ions in the solution collected at intervals of 7, 14 and 21 days was quantified by atomic absorption spectrophotometry. After the aging process, the brackets were analyzed by scanning electron microscopy (SEM under 22X and 1,000X magnifications. Results: Comparison of metal release in self-ligating and conventional brackets from the same manufacturer proved that the SCs group released more nickel (p < 0.05 than the GN group after 7 and 14 days, but less chromium (p < 0.05 after 14 days and less iron (p < 0.05 at the three experimental time intervals. The INs group released less iron (p < 0.05 than the GE group after 7 days and less nickel, chromium and iron (p < 0.05 after 14 and 21 days. The ECs group released more nickel, chromium and iron (p < 0.05 than the VE group after 14 days, but released less nickel and chromium (p < 0.05 after 7 days and less chromium and iron (p < 0.05 after 21 days. The SEM analysis revealed alterations on surface topography of conventional and self-ligating brackets. Conclusions: The aging process in self-ligating brackets was not greater than in conventional brackets from the same manufacturer. The null hypothesis was accepted.

  20. Infrared coagulation versus rubber band ligation in early stage hemorrhoids

    Directory of Open Access Journals (Sweden)

    P.J. Gupta


    Full Text Available The ideal therapy for early stages of hemorrhoids is always debated. Some are more effective but are more painful, others are less painful but their efficacy is also lower. Thus, comfort or efficacy is a major concern. In the present randomized study, a comparison is made between infrared coagulation and rubber band ligation in terms of effectiveness and discomfort. One hundred patients with second degree bleeding piles were randomized prospectively to either rubber band ligation (N = 54 or infrared coagulation (N = 46. Parameters measured included postoperative discomfort and pain, time to return to work, relief in incidence of bleeding, and recurrence rate. The mean age was 38 years (range 19-68 years. The mean duration of disease was 17.5 months (range 12 to 34 months. The number of male patients was double that of females. Postoperative pain during the first week was more intense in the band ligation group (2-5 vs 0-3 on a visual analogue scale. Post-defecation pain was more intense with band ligation and so was rectal tenesmus (P = 0.0059. The patients in the infrared coagulation group resumed their duties earlier (2 vs 4 days, P = 0.03, but also had a higher recurrence or failure rate (P = 0.03. Thus, we conclude that band ligation, although more effective in controlling symptoms and obliterating hemorrhoids, is associated with more pain and discomfort to the patient. As infrared coagulation can be conveniently repeated in case of recurrence, it could be considered to be a suitable alternative office procedure for the treatment of early stage hemorrhoids.

  1. Characterization of SLUG microwave amplifiers (United States)

    Hoi, I.-C.; Zhu, S.; Thorbeck, T.; McDermott, R.; Mutus, J.; Jeffrey, E.; Barends, R.; Chen, Y.; Roushan, P.; Fowler, A.; Sank, D.; White, T.; Campbell, B.; Chen, Z.; Chiaro, B.; Dunsworth, A.; Kelly, J.; Megrant, A.; Neill, C.; O'Malley, P. J. J.; Quintana, C.; Vainsencher, A.; Wenner, J.; Martinis, J. M.


    With the rapid growth of superconducting circuits quantum technology, a near quantum-limited amplifier at GHz frequency is needed to enable high fidelity measurements. We describe such an amplifier, the SQUID based, superconducting low inductance undulatory galvanometer (SLUG) amplifier. We measure the full scattering matrix of the SLUG. In particular, we measure both forward and reverse gain, as well as reflection. We see 15dB forward gain with added noise from one quanta to several quanta. The -1 dB compression point is around -95 dBm, about two orders of magnitude higher than that of typical Josephson parametric amplifiers. With these properties, SLUG is well suited for the high fidelity, simultaneous multiplexed readout of superconducting qubits.

  2. PID Controller with Operational Amplifier

    Directory of Open Access Journals (Sweden)

    Cristian Paul Chioncel


    Full Text Available The paper presents a PID controller made with LM741 operational amplifier that implement the PID controllers laws and allow for a widerange of applications of in the field of automatic control of technicalprocesses and systems.

  3. 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)


    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.

  4. TARC: Carlo Rubbia's Energy Amplifier

    CERN Multimedia

    Laurent Guiraud


    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.

  5. Operational amplifiers theory and design

    CERN Document Server

    Huijsing, Johan


    This proven textbook guides readers to a thorough understanding of the theory and design of operational amplifiers (OpAmps). The core of the book presents systematically the design of operational amplifiers, classifying them into a periodic system of nine main overall configurations, ranging from one gain stage up to four or more stages. This division enables circuit designers to recognize quickly, understand, and choose optimal configurations. Characterization of operational amplifiers is given by macro models and error matrices, together with measurement techniques for their parameters. Definitions are given for four types of operational amplifiers depending on the grounding of their input and output ports. Many famous designs are evaluated in depth, using a carefully structured approach enhanced by numerous figures. In order to reinforce the concepts introduced and facilitate self-evaluation of design skills, the author includes problems with detailed solutions, as well as simulation exercises. Provides te...


    Institute of Scientific and Technical Information of China (English)



    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.

  7. Comparison of multiplex ligation dependent probe amplification to immunohistochemistry for assessing HER-2/neu amplification in invasive breast cancer. (United States)

    Purnomosari, D; Aryandono, T; Setiaji, K; Nugraha, S B; Pals, G; van Diest, P J


    The HER-2/neu transmembrane tyrosine kinase receptor is both a prognostic marker and a therapeutic target for breast cancer. Accurate determination of HER-2/neu status is a prerequisite for selecting breast tumors for HER-2/neu immunotherapy or for taxan based chemotherapy. Unfortunately, there is no consensus concerning how this determination should be reached. We compared assessment of HER-2/neu status using Multiplex ligation-dependent probe amplification (MLPA) and immunohistochemistry (IHC). The patient group comprised 60 Indonesian breast cancers patients. IHC was performed on paraffin sections using the CB11 antibody from Novocastra. Results were scored according to the Hercept test. For MLPA, DNA was extracted from frozen samples, PCR amplified with a probe set containing three hemi-primer sets for the HER-2 locus and another nine control probes spread over chromosome 17 and other chromosomes, and analyzed on a gene scanner. A ratio above two for at least two HER-2 locus probes compared to the control probes was regarded as amplification. IHC for HER-2/neu was negative in 36 cases, and 24 cases (40%) showed expression. Seven, eight and nine of the latter cases were 1+, 2+ and 3+ positive, respectively. Forty-seven cases showed no amplification by MLPA, and 13 cases (22%) were amplified. Comparison of IHC and MPLA showed that none of the 36 IHC-negative or seven IHC 1+ cases was amplified. Five of the eight (63%) 2+ cases were amplified, and eight of nine (89%) of the IHC 3+ tumors showed gene amplification by MLPA assay. For HER-2/neu, there is a good correlation between gene amplification detected by MLPA and overexpression by IHC in invasive breast cancer. It appears that MLPA can detect the HER-2 amplified cases in the IHC 2+ class. Because MLPA is quick and inexpensive, it is an attractive method for detecting HER-2/neu amplification in daily laboratory practice.

  8. Level of arterial ligation in rectal cancer surgery: Low tie preferred over high tie. A review

    NARCIS (Netherlands)

    M.M. Lange (Marilyne); M. Buunen (Mark); C.J.H. van de Velde (Cornelis)


    textabstractConsensus does not exist on the level of arterial ligation in rectal cancer surgery. From oncologic considerations, many surgeons apply high tie arterial ligation (level of inferior mesenteric artery). Other strategies include ligation at the level of the superior rectal artery, just cau

  9. Ligation-free ribosome profiling of cell type-specific translation in the brain. (United States)

    Hornstein, Nicholas; Torres, Daniela; Das Sharma, Sohani; Tang, Guomei; Canoll, Peter; Sims, Peter A


    Ribosome profiling has emerged as a powerful tool for genome-wide measurements of translation, but library construction requires multiple ligation steps and remains cumbersome relative to more conventional deep-sequencing experiments. We report a new, ligation-free approach to ribosome profiling that does not require ligation. Library construction for ligation-free ribosome profiling can be completed in one day with as little as 1 ng of purified RNA footprints. We apply ligation-free ribosome profiling to mouse brain tissue to identify new patterns of cell type-specific translation and test its ability to identify translational targets of mTOR signaling in the brain.

  10. Addition of HOBt improves the conversion of thioester-Amine chemical ligation. (United States)

    Todorovski, Toni; Suñol, David; Riera, Antoni; Macias, Maria J


    The syntheses of large peptides and of those containing non-natural amino acids can be facilitated by the application of convergent approaches, dissecting the native sequence into segments connected through a ligation reaction. We describe an improvement of the ligation protocol used to prepare peptides and proteins without cysteine residues at the ligation junction. We have found that the addition of HOBt to the ligation, improves the conversion of the ligation reaction without affecting the epimerization rate or chemoselectivity, and it can be efficiently used with peptides containing phosphorylated amino acids.

  11. EMI-resilient amplifier circuits

    CERN Document Server

    van der Horst, Marcel J; Linnenbank, André C


    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...

  12. Model-guided ligation strategy for optimal assembly of DNA libraries. (United States)

    Ng, Daphne T W; Sarkar, Casim A


    DNA ligation is essential to many molecular biology manipulations, but this reaction is often carried out by following generic guidelines or by trial and error. Maximizing the desired ligation product is especially important in DNA library construction for directed evolution experiments since library diversity is directly affected by ligation efficiency. Here, we suggest that display vectors that rely on Type IIP restriction sites for cloning should be redesigned to utilize Type IIS restriction sites instead because ligation yield is significantly improved: we observed up to 15- and 2.6-fold increases in desired products for circular and linear ligation reactions, respectively. To guide ligation optimization more rationally, we developed an easily parameterized thermodynamic model that predicts product distributions based on input DNA concentrations and free energies of the ligation events. We applied this model to study ligation reactions using a ribosome display vector redesigned with Type IIS restriction sites (pRDV2). We computationally predicted and experimentally validated the relative abundance of various products in three-piece linear ligations as well as the extent of transformation from vector-insert circular ligations. Based on our results, we provide general insights into ligation and we outline guidelines for optimizing this reaction for both in vivo and in vitro display methodologies.

  13. Critical evaluation and rate constants of chemoselective ligation reactions for stoichiometric conjugations in water. (United States)

    Saito, Fumito; Noda, Hidetoshi; Bode, Jeffrey W


    Chemoselective ligation reactions have contributed immensely to the development of organic synthesis and chemical biology. However, the ligation of stoichiometric amounts of large molecules for applications such as protein-protein conjugates is still challenging. Conjugation reactions need to be fast enough to proceed under dilute conditions and chemoselective in the presence of unprotected functional groups; the starting materials and products must be stable under the reaction conditions. To compare known ligation reactions for their suitability under these conditions, we determined the second-order rate constants of ligation reactions using peptide substrates with unprotected functional groups. The reaction conditions, the chemoselectivity of the reactions, and the stability of the starting materials and products were carefully evaluated. In some cases, the stability could be improved by modifying the substrate structure. These data obtained under the ligation conditions provide a useful guide to choose an appropriate ligation reaction for synthesis of large molecules by covalent ligation reactions of unprotected substrates in water.

  14. Ligation Bias in Illumina Next-Generation DNA Libraries

    DEFF Research Database (Denmark)

    Seguin-Orlando, Andaine; Schubert, Mikkel; Clary, Joel


    Ancient DNA extracts consist of a mixture of endogenous molecules and contaminant DNA templates, often originating from environmental microbes. These two populations of templates exhibit different chemical characteristics, with the former showing depurination and cytosine deamination by......-products, resulting from post-mortem DNA damage. Such chemical modifications can interfere with the molecular tools used for building second-generation DNA libraries, and limit our ability to fully characterize the true complexity of ancient DNA extracts. In this study, we first use fresh DNA extracts to demonstrate...... that library preparation based on adapter ligation at AT-overhangs are biased against DNA templates starting with thymine residues, contrarily to blunt-end adapter ligation. We observe the same bias on fresh DNA extracts sheared on Bioruptor, Covaris and nebulizers. This contradicts previous reports suggesting...

  15. Click chemistry for rapid labeling and ligation of RNA. (United States)

    Paredes, Eduardo; Das, Subha R


    The copper(I)-promoted azide-alkyne cycloaddition reaction (click chemistry) is shown to be compatible with RNA (with free 2'-hydroxyl groups) in spite of the intrinsic lability of RNA. RNA degradation is minimized through stabilization of the Cu(I) in aqueous buffer with acetonitrile as cosolvent and no other ligand; this suggests the general possibility of "ligandless" click chemistry. With the viability of click chemistry validated on synthetic RNA bearing "click"-reactive alkynes, the scope of the reaction is extended to in-vitro-transcribed or, indeed, any RNA, as a click-reactive azide is incorporated enzymatically. Once clickable groups are installed on RNA, they can be rapidly click labeled or conjugated together in click ligations, which may be either templated or nontemplated. In click ligations the resultant unnatural triazole-linked RNA backbone is not detrimental to RNA function, thus suggesting a broad applicability of click chemistry in RNA biological studies.

  16. A CMOS current-mode operational amplifier

    DEFF Research Database (Denmark)

    Kaulberg, Thomas


    current-mode feedback amplifier or a constant bandwidth in a transimpedance feedback amplifier. The amplifier is found to have a gain-bandwidth product of 3 MHz, an offset current of 0.8 μA (signal range ±700 μA), and a (theoretically) unlimited slew rate. The amplifier is realized in a standard CMOS 2...

  17. Elastic band ligation of hemorrhoids: Flexible gastroscope or rigid proctoscope?

    Institute of Scientific and Technical Information of China (English)

    M Cazemier; RJF Felt-Bersma; MA Cuesta; CJJ Mulder


    AIM: To compare rigid proctoscope and flexible endoscope for elastic band ligation of internal hemorrhoids.METHODS: Patients between 18 and 80 years old, with chronic complaints (blood loss, pain, itching or prolapse)of internal hemorrhoids of grade Ⅰ-Ⅲ, were randomized to elastic band ligation by rigid proctoscope or flexible endoscope (preloaded with 7 bands). Patients were retreated every 6 wk until the cessation of complaints.Evaluation by three-dimensional anal endosonography was performed.RESULTS: Forty-one patients were included (median age 52.0, range 27-79 years, 20 men). Nineteen patients were treated with a rigid proctoscope and twenty two with a flexible endoscope. Twenty-nine patients had grade Ⅰ hemorrhoids, 9 patients had grade Ⅱ hemorrhoids and 3 patients had grade Ⅲ hemorrhoids.All patients needed a minimum of 1 treatment and a maximum of 3 treatments. A median of 4.0 bands was used in the rigid proctoscope group and a median of 6.0 bands was used in the flexible endoscope group (P < 0.05). Pain after ligation tended to be more frequent in patients treated with the flexible endoscope (first treatment: 3 vs 10 patients, P < 0.05). Threedimensional endosonography showed no sphincter defects or alterations in submucosal thickness.CONCLUSION: Both techniques are easy to perform,well tolerated and have a good and fast effect. It is easier to perform more ligations with the flexible endoscope. Additional advantages of the flexible scope are the maneuverability and photographic documentation.However, treatment with the flexible endoscope might be more painful and is more expensive.

  18. Capacitively-coupled chopper amplifiers

    CERN Document Server

    Fan, Qinwen; Huijsing, Johan H


    This book describes the concept and design of the capacitively-coupled chopper technique, which can be used in precision analog amplifiers. Readers will learn to design power-efficient amplifiers employing this technique, which can be powered by regular low supply voltage such as 2V and possibly having a +\\-100V input common-mode voltage input. The authors provide both basic design concepts and detailed design examples, which cover the area of both operational and instrumentation amplifiers for multiple applications, particularly in power management and biomedical circuit designs. Discusses basic working principles and details of implementation for proven designs; Includes a diverse set of applications, along with measurement results to demonstrate the effectiveness of the technique; Explains advantages and drawbacks of the technique, given particular circumstances.

  19. DNA hybridization and ligation for directed colloidal assembly (United States)

    Shyr, Margaret

    Colloidal assembly using DNA hybridization has been pursued as a means assemble non-conventional ordered colloidal structures. However, to date it is undetermined whether DNA hybridization can be used to achieve non-FCC colloidal crystals. Using microcontact printing techniques, we have fabricated covalently bound single stranded DNA (ssDNA) two-dimensional arrays on glass surfaces, which were used to direct the assembly of complementary DNA functionalized polystyrene colloids. Two of the hallmarks of DNA hybridization, sequence specificity and thermal reversibility, were demonstrated. Due to the periodicity of these arrays, laser diffraction was used to directly monitor these structures during assembly. To demonstrate the versatility of the 2D colloidal array assembled via DNA hybridization, a catalytic DNA sequence or DNAzyme was incorporated into the colloidal array system. By tethering the enzymatic strand to the patterned glass surface and the substrate strand to polystyrene colloids, we showed that the DNAzyme could prevent the assembly of the arrays when the required Pb2+ cofactor was provided. Attempts to assemble the colloid arrays and disassemble via the Pb2+-DNAzyme induced cleavage were unsuccessful, likely due to the incomplete cleavage of the multitude of hybridized linkages between each colloid and the surface. Since DNA is not only capable of catalyzing reactions, but also capable of being reacted upon by a variety of biological enzymes, we examined the use of DNA ligase as a means to control the assembly of DNA-functionalized colloids. A three-sequence linker system was used for the hybridization mediated assembly of colloids: one sequence was tethered to the surface of the glass slide or colloids, one was tethered to another colloid surface, and the linker sequence hybridizes simultaneously to both tethered sequences. Once hybridized, the two tethered fragments can be ligated using DNA ligase, resulting in a continuous sequence tethered on one end

  20. Thermal recovery of NIF amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, S.; Marshall, C.; Petty, C.; Smith, L.; van Wonterghem, B.; Mills, S.


    The issue of thermal recovery of the NIF amplifiers has taken on increased emphasis as program goals move toward increasing the shot rate to once every four hours. This paper addresses the technical issues associated with achieving thermal recovery in the NIF amplifiers. We identify two temperature related thermal recovery quantities: (1) the difference between the average slab temperature and the temperature of other surfaces in the amplifier cavity, and (2) the temperature difference in the slab over the aperture. The first quantity relates to optical disturbances in the gas column in the system, while the second quantity is associated with optical aberrations in the laser media itself. Calculations and experiments are used to quantify recovery criteria, and develop cooling approaches. The cooling approaches discussed are (1) active cooling of the flashlamps with ambient gas and chilled gas, and (2) active cooling of the slab edge cladding. Calculations indicate that the NIF baseline cooling approach of 20 cfm per lamp ambient temperature gas flow in both the central and side flashlamp cassettes is capable of meeting thermal recovery requirements for an 8 hour shot period, while to achieve a 4 hour shot period requires use of chilled gas and edge cladding cooling. In addition, the effect of changing the amplifier cavity and beamtube fill gas from nitrogen to helium is addressed, showing that a factor of 8 reduction in the sensitivity to thermal disturbances is possible. 6 refs., 9 figs., 1 tab.

  1. Regulation of inter- and intramolecular ligation with T4 DNA ligase in the presence of polyethylene glycol.


    Hayashi, K.; NAKAZAWA, M.; Ishizaki, Y; Hiraoka, N.; Obayashi, A


    Polyethylene glycol (PEG) stimulates ligation with T4 DNA ligase. In 10% (w/v) PEG 6,000 solutions, only intermolecular ligation is enhanced by monovalent cations, while both inter- and intramolecular ligation occur without their presence. Similar stimulation was also caused by divalent cations or polyamines in the PEG 6,000 solutions. Such properties of the ligase could be applied to control the extent of inter- and intramolecular ligation. Ligation with cations or polyamines in 10% PEG 6,00...

  2. Selective amplification of cDNA sequence from total RNA by cassette-ligation mediated polymerase chain reaction (PCR): application to sequencing 6.5 kb genome segment of hantavirus strain B-1. (United States)

    Isegawa, Y; Sheng, J; Sokawa, Y; Yamanishi, K; Nakagomi, O; Ueda, S


    A method, referred to as cassette-ligation mediated polymerase chain reaction (PCR), has been developed to permit selective and specific amplification of cDNA sequence from total cellular RNA. This technique comprises (i) digestion of cDNA with multiple restriction enzymes, (ii) ligation of cleavage products to double-stranded DNA cassettes possessing a corresponding restriction site and (iii) amplification of cassette-ligated restriction fragments containing a short, known sequence (but not all the other ligation products) by PCR using the specific and cassette primers; the specific primer is designed to prime synthesis from the known sequence of the cDNA whereas the cassette primer anneals to one strand of the cassette. Sequencing from the cassette primer provides information to design a new primer for the next walking step. The amplified cDNA fragments are often larger than the maximum DNA fragments (500-600 bp) that can be sequenced without the need of synthesizing internal sequencing primer. Each of such large cDNA fragments is dissected into smaller DNA fragments by repeating cassette-ligation mediated PCR exploiting different restriction sites and different sets of cassette primers. This dissection process reduces the number of specific primers to a minimum, thereby increasing the speed of sequencing and minimizing the overall cost. We have successfully applied this cDNA walking and sequencing by the cassette-ligation mediated PCR to the sequencing of an entire 6.5 kb genome segment of hantavirus strain B-1.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. CMOS Current-mode Operational Amplifier

    DEFF Research Database (Denmark)

    Kaulberg, Thomas


    current-mode feedback amplifier or a constant bandwidth in a transimpedance feedback amplifier. The amplifier is found to have a gain bandwidth product of 8 MHz, an offset current of 0.8 ¿A (signal-range ±700¿A) and a (theoretically) unlimited slew-rate. The amplifier is realized in a standard CMOS 2......A fully differential-input differential-output current-mode operational amplifier (COA) is described. The amplifier utilizes three second generation current-conveyors (CCII) as the basic building blocks. It can be configured to provide either a constant gain-bandwidth product in a fully balanced...

  4. Constructing recombinant replication-defective adenoviral vectors that express glucose transporter-1 through in vitro ligation

    Institute of Scientific and Technical Information of China (English)

    Fangcheng Li; Junliang Li; Ranyi Liu; Xinke Xu; Kaichang Yuan; Zhonghua Wu


    BACKGROUND: We constructed a homologous recombination bacterial method based on the pAdEasy system, a widely used system, for generating recombinant adenoviral vectors that express glucose transporter-1 (GLUT1) in rats.OBJECTIVE: This study was designed to investigate the feasibility of generating recombinant replication-defective adenoviral vectors that express GLUT1 in rats by in vitro ligation based on the Adeno-XTM system. DESIGN: An in vitro cell-based experiment. SETTING: This study was performed at the Linbaixin Medical Research Center of the Second Hospital Affiliated to Sun Yat-sen University and Central Laboratory for Prevention and Treatment of Tumor, Sun Yat-sen University between January and August 2004. MATERIALS: Male, adult, Sprague Dawley rats were used to extract total RNA from brain tissue. E. coli DH5?and human embryonic kidney 293 cells (HEK293 cells) used in the present study were cryo-preserved by the Second Hospital Affiliated to Sun Yat-sen University. Rabbit anti-rat GLUT1 polyclonal antibody (Chemicon, U.S.A.) and primers (Shanghai Boya Bioengineering Co., Ltd) were also used. METHODS: E1/E3-deleted replication-defective adenoviral vectors were used. Using in vitro ligation, the target gene was first sub-cloned into a shuttle vector plasmid to obtain the fragment containing target gene expression cassettes by enzyme digestion. Subsequently, the fragment was co-transformed with linearized adenoviral backbone vector into the E. coli strain. The recombinant adenoviral plasmid was transfected into HEK293 cells to assembly recombinant adenoviral vectors with replication capabilities. The procedure was repeated several times for recombinant adenoviral vectors amplification. MAIN OUTCOME MEASURES: Efficiency of recombinant adenoviral vectors to express the target gene was measured by gene and protein expression through polymerase chain reaction and Western Blot assays, respectively.RESULTS: Results demonstrated that recombinant adenoviral

  5. In Vitro Selection of Optimal DNA Substrates for Ligation by a Water-Soluble Carbodiimide (United States)

    Harada, Kazuo; Orgel, Leslie E.


    We have used in vitro selection to investigate the sequence requirements for efficient template-directed ligation of oligonucleotides at 0 deg C using a water-soluble carbodiimide as condensing agent. We find that only 2 bp at each side of the ligation junction are needed. We also studied chemical ligation of substrate ensembles that we have previously selected as optimal by RNA ligase or by DNA ligase. As anticipated, we find that substrates selected with DNA ligase ligate efficiently with a chemical ligating agent, and vice versa. Substrates selected using RNA ligase are not ligated by the chemical condensing agent and vice versa. The implications of these results for prebiotic chemistry are discussed.

  6. Telmisartan attenuates hepatic fibrosis in bile duct-ligated rats

    Institute of Scientific and Technical Information of China (English)

    En-tong YI; Rui-xia LIU; Yan WEN; Cheng-hong YIN


    Aim: To evaluate the antifibrotic effect of telmisartan,an angiotensin Ⅱ receptor blocker,in bile duct-ligated rats.Methods: Adult Sprague-Dawley rats were allocated to 3 groups: sham-operated rats,model rats underwent common bile duct ligation (BDL),and BDL rats treated with telmisartan (8 mg/kg,po,for 4 weeks).The animals were sacrificed on d 29,and liver histology was examined,the Knodell and Ishak scores were assigned,and the expression of angiotensin-converting enzyme (ACE) and ACE2 was evaluated with immunohistochemical staining.The mRNAs and proteins associated with liver fibrosis were evaluated using RTQ-PCR and Western blot,respectively.Results: The mean fibrosis score of BDL rats treated with telmisartan was significantly lower than that of the model rats (1.66±0.87 vs 2.13±0.35,P=0.015).However,there was no significant difference in inflammation between the two groups,both of which showed moderate inflammation.Histologically,treatment with telmisartan significantly ameliorated BDL-caused the hepatic fibrosis.Treatment with telmisartan significantly upregulated the mRNA levels of ACE2 and MAS,and decreased the mRNA levels of ACE,angiotensin Ⅱ type 1 receptor (AT1-R),collagen type Ⅲ,and transforming growth factor β1 (TGF-β1).Moreover,treatment with telmisartan significantly increased the expression levels of ACE2 and MAS proteins,and inhibited the expression levels of ACE and AT1-R protein.Conclusion: Telmisartan attenuates liver fibrosis in bile duct-ligated rats via increasing ACE2 expression level.

  7. Synthesis of heteroglycoclusters by using orthogonal chemoselective ligations

    Directory of Open Access Journals (Sweden)

    Baptiste Thomas


    Full Text Available Synthetic heteroglycoclusters are being subjected to increasing interest due to their potential to serve as selective ligands for carbohydrate-binding proteins. In this paper, we describe an expedient strategy to prepare cyclopeptides displaying well-defined distributions and combinations of carbohydrates. By using both oxime ligation and copper(I-catalyzed alkyne–azide cycloaddition, two series of compounds bearing binary combinations of αMan, αFuc or βLac in an overall tetravalent presentation, and either 2:2 or 3:1 relative proportions, have been prepared.

  8. Post-functionalization of polymers via orthogonal ligation chemistry. (United States)

    Goldmann, Anja S; Glassner, Mathias; Inglis, Andrew J; Barner-Kowollik, Christopher


    The establishment of advanced living/controlled polymerization protocols allows for engineering synthetic polymers in a precise fashion. Combining advanced living/controlled polymerization techniques with highly efficient coupling chemistries facilitates quantitative, modular, and orthogonal functionalization of synthetic polymer strands at their chain termini as well as side-chain functionalization. The review highlights the current status of selected post-functionalization techniques of polymers via orthogonal ligation chemistries, major characteristics of the specific transformation chemistry, as well as the characterization of the products.

  9. Expressed protein ligation for metalloprotein design and engineering. (United States)

    Clark, Kevin M; van der Donk, Wilfred A; Lu, Yi


    Metalloproteins contain highly specialized metal-binding sites that are designed to accept specific metal ions to maintain correct function. Although many of the sites have been modified with success, the relative paucity of functional group availability within proteinogenic amino acids can sometimes leave open questions about specific functions of the metal binding ligands. Attaining a more thorough analysis of individual amino acid function within metalloproteins has been realized using expressed protein ligation (EPL). Here we describe our recent efforts using EPL to incorporate nonproteinogenic cysteine and methionine analogues into the type 1 copper site found in Pseudomonas aeruginosa azurin.

  10. Linearisation of RF Power Amplifiers

    DEFF Research Database (Denmark)

    Nielsen, Per Asbeck


    This thesis deals with linearisation techniques of RF power amplifiers (PA), PA design techniques and integration of the necessary building blocks in a CMOS technology. The opening chapters introduces the theory of transmitter architectures, RF-signal representation and the principles of digital...... modulation. Furthermore different types of power amplifiers, models and measures of non-linearities are presented. A chapter is also devoted to different types of linearisation systems. The work carried out and described in this thesis can be divided into a more theoretical and system oriented treatment...... 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...

  11. Single conversion stage amplifier - SICAM

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.


    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

  12. 338-GHz Semiconductor Amplifier Module (United States)

    Samoska, Lorene A.; Gaier, Todd C.; Soria, Mary M.; Fung, King Man; Rasisic, Vesna; Deal, William; Leong, Kevin; Mei, Xiao Bing; Yoshida, Wayne; Liu, Po-Hsin; Uyeda, Jansen; Lai, Richard


    Research findings were reported from an investigation of new gallium nitride (GaN) monolithic millimeter-wave integrated circuit (MMIC) power amplifiers (PAs) targeting the highest output power and the highest efficiency for class-A operation in W-band (75-110 GHz). W-band PAs are a major component of many frequency multiplied submillimeter-wave LO signal sources. For spectrometer arrays, substantial W-band power is required due to the passive lossy frequency multipliers.

  13. Small and lightweight power amplifiers (United States)

    Shams, Qamar A.; Barnes, Kevin N.; Fox, Robert L.; Moses, Robert W.; Bryant, Robert G.; Robinson, Paul C.; Shirvani, Mir


    The control of u wanted structural vibration is implicit in most of NASA's programs. Currently several approaches to control vibrations in large, lightweight, deployable structures and twin tail aircraft at high angles of attack are being evaluated. The Air Force has been examining a vertical tail buffet load alleviation system that can be integrated onboard an F/A-18 and flown. Previous wind tunnel and full-scale ground tests using distributed actuators have shown that the concept works; however, there is insufficient rom available onboard an F/A-18 to store current state-of- the-art system components such as amplifiers, DC-to-DC converter and a computer for performing vibration suppression. Sensor processing, power electronics, DC-to-DC converters, and control electronics that may be collocated with distributed actuators, are particularly desirable. Such electronic system would obviate the need for complex, centralized, control processing and power distribution components that will eliminate the weight associated with lengthy wiring and cabling networks. Several small and lightweight power amplifiers ranging from 300V pp to 650V pp have been designed using off the shelf components for different applications. In this paper, the design and testing of these amplifiers will be presented under various electrical loads.

  14. SPS RF System Amplifier plant

    CERN Multimedia


    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.

  15. High power regenerative laser amplifier (United States)

    Miller, J.L.; Hackel, L.A.; Dane, C.B.; Zapata, L.E.


    A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse. 7 figures.

  16. Evaluation of cerebral electrical activity and cardiac output after patent ductus arteriosus ligation in preterm infants.

    LENUS (Irish Health Repository)

    Leslie, A T F S


    To characterize and investigate the relationship between systemic blood flow and pre- and postoperative cerebral electrical activity in preterm neonates undergoing patent ductus arteriosus (PDA) ligation.

  17. Analog circuit design designing high performance amplifiers

    CERN Document Server

    Feucht, Dennis


    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.

  18. Higher order mode optical fiber Raman amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Friis, Søren Michael Mørk; Usuga Castaneda, Mario A.;


    We review higher order mode Raman amplifiers and discuss recent theoretical as well as experimental results including system demonstrations.......We review higher order mode Raman amplifiers and discuss recent theoretical as well as experimental results including system demonstrations....

  19. Challenges in higher order mode Raman amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Nielsen, Kristian; Friis, Søren Michael Mørk;


    A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed......A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed...

  20. Improved charge amplifier using hybrid hysteresis compensation (United States)

    Amin-Shahidi, Darya; Trumper, David L.


    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.

  1. European Research on THz Vacuum Amplifiers

    DEFF Research Database (Denmark)

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


    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...... of the European research, academy and industry in vacuum electronics. This paper describes the status of the project and progress towards the THz amplifier realization....

  2. low pump power photonic crystal fibre amplifiers

    DEFF Research Database (Denmark)

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


    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....

  3. A High-performance Small Signal Amplifier

    Institute of Scientific and Technical Information of China (English)


    According to questions in the design of high quality small signal amplifier, this paper gave a new-type high performance small signal amplifier. The paper selected the operational amplifier of ICL Company and designed a new-type circuit with simple, low cost and excellent performance.

  4. Vascular Z-shaped ligation technique in surgical treatmentof haemorrhoid

    Institute of Scientific and Technical Information of China (English)

    KazIm Gemici; Ahmet Okus; Serden Ay


    AIM To present the effectiveness of minimal invasivevascular zet ligation in the surgical treatment ofhaemorrhoidal disease (HD).METHODS: Among 138 patients with 2nd-4th gradeinternal HD having several complaints and operatedat our hospital between 2003-2013; 116 patients whoregularly attended 1-year control were included in thestudy. Operation times, postoperative early period pain,satisfaction score, complications and relapse detailswere obtained from computer records retrospectively.Visual Analogous Scale (VAS) scores were used forpatient satisfaction on the 3rd, 7th and 21st days.Technique; fixed suture which is constituted by thefirst leg of the Z-shaped suture (to pass by the mucosaand muscular layer) was put in the pile root in order toensure vascular ligation and fixation. The second legof the Z-shaped suture is constituted by mobile sutureand it passes by the pile mucosa and submucosa whichprolapses 5-10 mm below the first suture.RESULTS: Seventy-five of the patients (65%) weremale, 41 of them (35%) were female and their ageaverage was 41. The mean operation time was 12 ±4.8 min. VAS/satisfaction score was found as 2.2/4.3,1.8/4.0, 1.2/4.4 respectively on the 3rd, 7th, and 21stdays. Four of the patient (3.5%) had relapse.CONCLUSION: This technique is an easily applicable,cost efficient way of operation which increases patientsatisfaction.

  5. TLR9 ligation in pancreatic stellate cells promotes tumorigenesis. (United States)

    Zambirinis, Constantinos P; Levie, Elliot; Nguy, Susanna; Avanzi, Antonina; Barilla, Rocky; Xu, Yijie; Seifert, Lena; Daley, Donnele; Greco, Stephanie H; Deutsch, Michael; Jonnadula, Saikiran; Torres-Hernandez, Alejandro; Tippens, Daniel; Pushalkar, Smruti; Eisenthal, Andrew; Saxena, Deepak; Ahn, Jiyoung; Hajdu, Cristina; Engle, Dannielle D; Tuveson, David; Miller, George


    Modulation of Toll-like receptor (TLR) signaling can have protective or protumorigenic effects on oncogenesis depending on the cancer subtype and on specific inflammatory elements within the tumor milieu. We found that TLR9 is widely expressed early during the course of pancreatic transformation and that TLR9 ligands are ubiquitous within the tumor microenvironment. TLR9 ligation markedly accelerates oncogenesis, whereas TLR9 deletion is protective. We show that TLR9 activation has distinct effects on the epithelial, inflammatory, and fibrogenic cellular subsets in pancreatic carcinoma and plays a central role in cross talk between these compartments. Specifically, TLR9 activation can induce proinflammatory signaling in transformed epithelial cells, but does not elicit oncogene expression or cancer cell proliferation. Conversely, TLR9 ligation induces pancreatic stellate cells (PSCs) to become fibrogenic and secrete chemokines that promote epithelial cell proliferation. TLR9-activated PSCs mediate their protumorigenic effects on the epithelial compartment via CCL11. Additionally, TLR9 has immune-suppressive effects in the tumor microenvironment (TME) via induction of regulatory T cell recruitment and myeloid-derived suppressor cell proliferation. Collectively, our work shows that TLR9 has protumorigenic effects in pancreatic carcinoma which are distinct from its influence in extrapancreatic malignancies and from the mechanistic effects of other TLRs on pancreatic oncogenesis.

  6. Binding-regulated click ligation for selective detection of proteins. (United States)

    Cao, Ya; Han, Peng; Wang, Zhuxin; Chen, Weiwei; Shu, Yongqian; Xiang, Yang


    Herein, a binding-regulated click ligation (BRCL) strategy for endowing selective detection of proteins is developed with the incorporation of small-molecule ligand and clickable DNA probes. The fundamental principle underlying the strategy is the regulating capability of specific protein-ligand binding against the ligation between clickable DNA probes, which could efficiently combine the detection of particular protein with enormous DNA-based sensing technologies. In this work, the feasibly of the BRCL strategy is first verified through agarose gel electrophoresis and electrochemical impedance spectroscopy measurements, and then confirmed by transferring it to a nanomaterial-assisted fluorescence assay. Significantly, the BRCL strategy-based assay is able to respond to target protein with desirable selectivity, attributing to the specific recognition between small-molecule ligand and its target. Further experiments validate the general applicability of the sensing method by tailoring the ligand toward different proteins (i.e., avidin and folate receptor), and demonstrate its usability in complex biological samples. To our knowledge, this work pioneers the practice of click chemistry in probing specific small-molecule ligand-protein binding, and therefore may pave a new way for selective detection of proteins.

  7. Development of hepatorenal syndrome in bile duct ligated rats

    Institute of Scientific and Technical Information of China (English)

    Regina M Pereira; Ana Cristina Sim(o)es e Silva; Robson AS dos Santos; Eduardo A Oliveira; Virg(i)nia HR Leite; Filipi LC Dias; Alysson S Rezende; Lincoln P Costa; Luciola S Barcelos; Mauro M Teixeira


    AIM: To evaluate in bile duct ligated rats whether there were progressive alterations of renal function without changes in histopathology.METHODS: Male Wistar rats were submitted to sham-surgery or bile duct ligation (BDL) and divided according to the post-procedure time (2, 4 and 6-wk).To determine renal function parameters, rats were placed in metabolic cages and, at the end of the experiment, blood and urine samples were obtained.Histology and hydroxyproline content were analyzed in liver and renal tissue.RESULTS: Rats with 2 wk of BDL increased free water clearance (P = 0.02), reduced urinary osmolality (P =0.03) and serum creatinine (P = 0.01) in comparison to the sham group. In contrast, rats at 6 wk of BDL showed features of HRS, including significant increase in serum creatinine and reductions in creatinine clearance,water excretion and urinary sodium concentration. Rats with 4 wk of BDL exhibited an intermediate stage of renal dysfunction. Progressive hepatic fibrosis according to post-procedure time was confirmed by histology.The increased levels of liver hydroxyproline contrasted with the absence of structural changes in the kidney, as assessed by histology and unchanged hydroxyproline content in renal tissue.CONCLUSION: Our data show that BDL produced progressive renal dysfunction without structural changes in the kidney, characterizing HRS. The present model will be useful to understand the pathophysiology of HRS.

  8. Semisynthesis of Ribonuclease A using Intein-Mediated Protein Ligation

    Directory of Open Access Journals (Sweden)

    Ulrich Arnold


    Full Text Available The introduction of non-natural amino acid residues or modules into proteins provides a new means to explore the basis for conformational stability, folding/unfolding behavior, or biological function. We exploited intein-mediated protein ligation to produce a semisynthetic ribonuclease A. Of the 124 residues of RNase A, residues 1–94 were linked to an intein. After expression of the fusion protein and thiol-induced cleavage, the RNase A(1–94 fragment possessed a C-terminal thioester. A peptide identical to the C-terminal residues 95–124 of RNase A (with residue 95 being cysteine was successfully ligated to that thioester thereby reconstituting full-length wild-type RNase A. In mass spectrometry, this semisynthetic RNase A proved to be undistinguishable from the control protein, namely recombinant wild-type RNase A. Recombinant wild-type RNase A was obtained by expression of RNase A(1–124–intein fusion protein followed by thiol-induced cleavage and hydrolysis of the thioester. Both proteins showed thermal stabilities (Tm and catalytic activities comparable to the wild-type enzyme, indicating that both proteins folded properly. These results might serve as basis for the semisynthesis of RNase A variants containing non-natural modules in the aforementioned peptide.

  9. Log amplifier with pole-zero compensation (United States)

    Brookshier, William


    A logarithmic amplifier circuit provides pole-zero compensation for improved stability and response time over 6-8 decades of input signal frequency. The amplifier circuit includes a first operational amplifier with a first feedback loop which includes a second, inverting operational amplifier in a second feedback loop. The compensated output signal is provided by the second operational amplifier with the log elements, i.e., resistors, and the compensating capacitors in each of the feedback loops having equal values so that each break point or pole is offset by a compensating break point or zero.

  10. Semiconductor quantum-dot lasers and amplifiers

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Borri, Paola; Ledentsov, N. N.


    -power 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 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...

  11. 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 digital 0...

  12. High temperature charge amplifier for geothermal applications (United States)

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


    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.

  13. Audio power amplifier design handbook

    CERN Document Server

    Self, Douglas


    This book is essential for audio power amplifier designers and engineers for one simple 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

  14. Level of arterial ligation in total mesorectal excision (TME): An anatomical study

    NARCIS (Netherlands)

    M. Buunen (Mark); M.M. Lange (Marilyne); M. Ditzel (Max); G.J. Kleinrensink (Gert Jan); C.J.H. van de Velde (Cornelis)


    textabstractIntroduction: High-tie ligation is a common practice in rectal cancer surgery. However, it compromises perfusion of the proximal limb of the anastomosis. This anatomical study was designed to assess the value of low-tie ligation in order to obtain a tension-free anastomosis. Materials an

  15. A facile avenue to conductive polymer brushes via cyclopentadiene-maleimide Diels-Alder ligation. (United States)

    Yameen, Basit; Rodriguez-Emmenegger, Cesar; Preuss, Corinna M; Pop-Georgievski, Ognen; Verveniotis, Elisseos; Trouillet, Vanessa; Rezek, Bohuslav; Barner-Kowollik, Christopher


    Cyclopentadienyl end-capped poly(3-hexylthiophene) was employed to fabricate conductive surface tethered polymer brushes via a facile route based on cyclopentadiene-maleimide Diels-Alder ligation. The efficient nature of the Diels-Alder ligation was further combined with a biomimetic polydopamine-assisted functionalization of surfaces, making it an access route of choice for P3HT surface immobilization.

  16. Banding ligation versus beta-blockers as primary prophylaxis in esophageal varices

    DEFF Research Database (Denmark)

    Gluud, Lise L; Klingenberg, Sarah; Nikolova, Dimitrinka


    To compare banding ligation versus beta-blockers as primary prophylaxis in patients with esophageal varices and no previous bleeding.......To compare banding ligation versus beta-blockers as primary prophylaxis in patients with esophageal varices and no previous bleeding....

  17. One-pot native chemical ligation by combination of two orthogonal thioester precursors. (United States)

    Asahina, Yuya; Kawakami, Toru; Hojo, Hironobu


    We developed a one-pot peptide ligation method using two orthogonal thioester precursors and a protecting group for the ligation reaction between Asp and Cys. Combination of the two precursors facilitated the one-pot operation and yielded the entire polypeptide. The usefulness of this method was successfully demonstrated by the total synthesis of histone H4.

  18. Preparing a re-sequencing DNA library of 2 cancer candidate genes using the ligation-by-amplification protocol by two PCR reactions

    Institute of Scientific and Technical Information of China (English)

    SU YeYang; LIN Lin; TIAN Geng; CHEN Chen; LIU Tao; XU Xingya; QI XinPeng; ZHANG XiuQing; YANG HuanMing


    To meet the needs of large-scale genomic/genetic studies, the next-generation massively parallelized sequencing technologies provide high throughput, low cost and low labor-intensive sequencing ser-vice, with subsequent bioinformatic software and laboratory methods developed to expand their ap-plications in various types of research. PCR-based genomic/genetic studies, which have significant usage in association studies like cancer research, haven't benefited much from those next-generation sequencing technologies, because the shortgun re-sequencing strategy used by such sequencing machines as the Illumina/Solexa Genome Analyzer may not be applied to direct re-sequencing of short-length target regions like those in PCR-based genomic/genetic studies. Although several meth-ods have been proposed to solve this problem, including microarray-based genomic selections and selector-based technologies, they require advanced equipment and procedures which limit their ap-plications in many laboratories. By contrast, we overcame such potential drawbacks by utilizing a liga-tion by amplification (LBA) protocol, a method using a pair of Universal Adapters to randomly ligate target regions in a two-step-PCR procedure, whose Long LBA products were easily fragmented and sequenced on the next-generation sequencing machine. In this concept-proven study, we chose the consensus coding sequences of two human cancer genes: BRCA1 and BRCA2 as target regions, spe-cifically designed LBA primer pairs to amplify and randomly ligate them. 70 target sequences were successfully amplified and ligated into Long LBA products, which were then fragmented to construct DNA libraries for sequencing on both a conventional Sanger sequencer ABI 3730xl DNA Analyzer and the next-generation 'synthesis by sequencing technology' IlluminalSolexa Genome Analyzer. Bioin-formatic analysis demonstrated the utility and efficiency (including the coverage and depth of each target sequence and the SNPs detection

  19. Preparing a re-sequencing DNA library of 2 cancer candidate genes using the ligation-by-amplification protocol by two PCR reactions

    Institute of Scientific and Technical Information of China (English)


    To meet the needs of large-scale genomic/genetic studies, the next-generation massively parallelized sequencing technologies provide high throughput, low cost and low labor-intensive sequencing service, with subsequent bioinformatic software and laboratory methods developed to expand their applications in various types of research. PCR-based genomic/genetic studies, which have significant usage in association studies like cancer research, haven’t benefited much from those next-generation sequencing technologies, because the shortgun re-sequencing strategy used by such sequencing machines as the Illumina/Solexa Genome Analyzer may not be applied to direct re-sequencing of short-length target regions like those in PCR-based genomic/genetic studies. Although several methods have been proposed to solve this problem, including microarray-based genomic selections and selector-based technologies, they require advanced equipment and procedures which limit their applications in many laboratories. By contrast, we overcame such potential drawbacks by utilizing a ligation by amplification (LBA) protocol, a method using a pair of Universal Adapters to randomly ligate target regions in a two-step-PCR procedure, whose Long LBA products were easily fragmented and sequenced on the next-generation sequencing machine. In this concept-proven study, we chose the consensus coding sequences of two human cancer genes: BRCA1 and BRCA2 as target regions, specifically designed LBA primer pairs to amplify and randomly ligate them. 70 target sequences were successfully amplified and ligated into Long LBA products, which were then fragmented to construct DNA libraries for sequencing on both a conventional Sanger sequencer ABI 3730xl DNA Analyzer and the next-generation ’synthesis by sequencing technology’ Illumina/Solexa Genome Analyzer. Bioinformatic analysis demonstrated the utility and efficiency (including the coverage and depth of each target sequence and the SNPs detection

  20. [Is a hysterectomy justifiable to prevent post-tubal ligation syndrome?]. (United States)

    Maheux, R; Fugère, P


    Among 2057 tubal ligations performed between 1971-75 in "Hopital Saint-Luc" in Montreal, 78 patients had to be readmitted for hysterectomy. The main indication for hysterectomy among these patients was for menstrual disorders (65%). These menstrual disorders were present at the moment of the tubal ligation in about half of the patients. Among the patients who had to be reoperated for hysterectomy for menstrual disorders and who were asymptomatic at the momemt of their tubal ligation, 88% were using oral contraceptives for a mean period of 5.8 years. The low incidence of hysterectomy post-tubal ligation (3.8%) does not seem to justify a total hysterectomy to prevent what has been described as the "post tubal ligation syndrome" in the patients who are asymptomatic and desire a permanent sterilization. (Author's modified)

  1. In vivo multiphoton imaging of bile duct ligation (United States)

    Liu, Yuan; Li, Feng-Chieh; Chen, Hsiao-Chin; Chang, Po-shou; Yang, Shu-Mei; Lee, Hsuan-Shu; Dong, Chen-Yuan


    Bile is the exocrine secretion of liver and synthesized by hepatocytes. It is drained into duodenum for the function of digestion or drained into gallbladder for of storage. Bile duct obstruction is a blockage in the tubes that carry bile to the gallbladder and small intestine. However, Bile duct ligation results in the changes of bile acids in serum, liver, urine, and feces1, 2. In this work, we demonstrate a novel technique to image this pathological condition by using a newly developed in vivo imaging system, which includes multiphoton microscopy and intravital hepatic imaging chamber. The images we acquired demonstrate the uptake, processing of 6-CFDA in hepatocytes and excretion of CF in the bile canaliculi. In addition to imaging, we can also measure kinetics of the green fluorescence intensity.

  2. [Hypogastric artery ligation. Safety and efficacy of a training program]. (United States)

    García López, A; Martínez Aguirre, R; Hernández Romero, F; Naranjo Gutierrez, A; Montes Reyes, J


    Bilateral hypogastric artery ligation is a technique described in the antiquity to restrain the hemorrhage in the gynecological and obstetric surgery. There are few Gineco-obstetricians that dominate the technique, for what intended a training program, in which was to demonstrate their security and effectiveness. We carry out a program where were qualified 14 gineco-obstetricians, theoretical and surgically. Results were analyzed finding an acceptable security with 1.5% of complications and an effectiveness demonstrated when having to the program 92.9% of students that reached the competition. We intend to reply the course in other hospital units, in order to decrease the maternal mortality for hemorrhage obstetric or gynecological.

  3. Seamless Ligation Cloning Extract (SLiCE) cloning method. (United States)

    Zhang, Yongwei; Werling, Uwe; Edelmann, Winfried


    SLiCE (Seamless Ligation Cloning Extract) is a novel cloning method that utilizes easy to generate bacterial cell extracts to assemble multiple DNA fragments into recombinant DNA molecules in a single in vitro recombination reaction. SLiCE overcomes the sequence limitations of traditional cloning methods, facilitates seamless cloning by recombining short end homologies (15-52 bp) with or without flanking heterologous sequences and provides an effective strategy for directional subcloning of DNA fragments from bacterial artificial chromosomes or other sources. SLiCE is highly cost-effective and demonstrates the versatility as a number of standard laboratory bacterial strains can serve as sources for SLiCE extract. We established a DH10B-derived E. coli strain expressing an optimized λ prophage Red recombination system, termed PPY, which facilitates SLiCE with very high efficiencies.

  4. Universal ligation-detection-reaction microarray applied for compost microbes

    Directory of Open Access Journals (Sweden)

    Romantschuk Martin


    Full Text Available Abstract Background Composting is one of the methods utilised in recycling organic communal waste. The composting process is dependent on aerobic microbial activity and proceeds through a succession of different phases each dominated by certain microorganisms. In this study, a ligation-detection-reaction (LDR based microarray method was adapted for species-level detection of compost microbes characteristic of each stage of the composting process. LDR utilises the specificity of the ligase enzyme to covalently join two adjacently hybridised probes. A zip-oligo is attached to the 3'-end of one probe and fluorescent label to the 5'-end of the other probe. Upon ligation, the probes are combined in the same molecule and can be detected in a specific location on a universal microarray with complementary zip-oligos enabling equivalent hybridisation conditions for all probes. The method was applied to samples from Nordic composting facilities after testing and optimisation with fungal pure cultures and environmental clones. Results Probes targeted for fungi were able to detect 0.1 fmol of target ribosomal PCR product in an artificial reaction mixture containing 100 ng competing fungal ribosomal internal transcribed spacer (ITS area or herring sperm DNA. The detection level was therefore approximately 0.04% of total DNA. Clone libraries were constructed from eight compost samples. The LDR microarray results were in concordance with the clone library sequencing results. In addition a control probe was used to monitor the per-spot hybridisation efficiency on the array. Conclusion This study demonstrates that the LDR microarray method is capable of sensitive and accurate species-level detection from a complex microbial community. The method can detect key species from compost samples, making it a basis for a tool for compost process monitoring in industrial facilities.


    Directory of Open Access Journals (Sweden)

    I Made Arya Winangun


    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Hemorrhoid is regarded as the cases most seen in population. The prevalence of this cases about 4,4% with the incidence 12 of 1.000 patient. The current management of hemorrhoid is lifestyle modification, conservative management such as farmacology, minimally invasive treatment and more aggressive therapy using surgical procedure. Rubber band ligation was one of the minimally invasive procedures. This procedure was easy, inexpensive, and can be done outpatient using simple tools without complicated procedure like hemorrhoidectomy. Some studies explained rubber band ligation effectively done in internal hemorrhoid grade II and grade III even this procedure still had minimal complication such as bleeding and unpleasentness /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  6. High power RF solid state power amplifier system (United States)

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


    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.

  7. Quantum Noise in Amplifiers and Hawking/Dumb-Hole Radiation as Amplifier Noise

    CERN Document Server

    Unruh, W G


    The quantum noise in a linear amplifier is shown to be thermal noise. The theory of linear amplifiers is applied first to the simplest, single or double oscillator model of an amplifier, and then to linear model of an amplifier with continuous fields and input and outputs. Finally it is shown that the thermal noise emitted by black holes first demonstrated by Hawking, and of dumb holes (sonic and other analogs to black holes), arises from the same analysis as for linear amplifiers. The amplifier noise of black holes acting as amplifiers on the quantum fields living in the spacetime surrounding the black hole is the radiation discovered by Hawking. For any amplifier, that quantum noise is completely characterized by the attributes of the system regarded as a classical amplifier, and arises out of those classical amplification factors and the commutation relations of quantum mechanics.


    Directory of Open Access Journals (Sweden)

    Trunev A. P.


    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

  9. Coarctation of the Aorta as a Complication of Surgical Ligation of Patent Ductus Arteriosus in a Premature Infant (United States)

    Qasim, Amna; Jain, Sunil K.; Jiwani, Amyn K.


    Surgical ligation of a patent ductus arteriosus (PDA) is a commonly performed procedure. Complications are infrequent and most commonly include recurrent laryngeal nerve injury and rarely ligation of left pulmonary artery. We report a case of accidental ligation of the descending thoracic aorta leading to a clinically significant coarctation. PMID:28386503

  10. Locoregional MYCN-amplified neuroblastoma. (United States)

    Morales La Madrid, Andres; Volchenboum, Samuel; Gastier-Foster, Julie M; Pyatt, Robert; Liu, Don; Pytel, Peter; Lavarino, Cinzia; Rodriguez, Eva; Cohn, Susan L


    MYCN-amplification is strongly associated with other high-risk prognostic factors and poor outcome in neuroblastoma. Infrequently, amplification of MYCN has been identified in localized tumors with favorable biologic features. Outcome for these children is difficult to predict and optimal treatment strategies remain unclear. We report a 5-month-old who presented with an MYCN-amplified INSS stage 3, pelvic neuroblastoma. The tumor had favorable histology, hyperdiploidy, and lacked 1p36 and 11q23 aberrations. Although the patient met the criteria for high-risk neuroblastoma, because of the discordant prognostic markers we elected to treat her according to an intermediate-risk protocol. She remains event-free more than 18 months.

  11. Transverse pumped laser amplifier architecture (United States)

    Bayramian, Andrew James; Manes, Kenneth; Deri, Robert; Erlandson, Al; Caird, John; Spaeth, Mary


    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.

  12. Reflection amplifiers in self-regulated learning

    NARCIS (Netherlands)

    Verpoorten, Dominique


    Verpoorten, D. (2012). Reflection amplifiers in self-regulated learning. Doctoral thesis. November, 9, 2012, Heerlen, The Netherlands: Open Universiteit (CELSTEC). Datawyse / Universitaire Pers Maastricht.

  13. Enhanced Gain in Photonic Crystal Amplifiers

    DEFF Research Database (Denmark)

    Ek, Sara; Semenova, Elizaveta; Hansen, Per Lunnemann;


    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......We experimentally demonstrate enhanced gain in the slow-light regime of quantum well photonic crystal amplifiers. A strong gain enhancement is observed with the increase of the group refractive index, due to light slow-down. The slow light enhancement is shown in a amplified spontaneous emission...

  14. Design of an 1800nm Raman amplifier

    DEFF Research Database (Denmark)

    Svane, Ask Sebastian; Rottwitt, Karsten


    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...... 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....

  15. Dynamics of Soliton Cascades in Fiber Amplifiers

    CERN Document Server

    Arteaga-Sierra, F R; Agrawal, Govind P


    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.

  16. Persistent postpartum haemorrhage after failed arterial ligation: value of pelvic embolisation

    Energy Technology Data Exchange (ETDEWEB)

    Fargeaudou, Yann; Soyer, Philippe; Sirol, Marc; Boudiaf, Mourad; Dahan, Henri; Dref, Olivier le [Hopital Lariboisiere AP-HP et Universite Diderot-Paris 7, Department of Abdominal and Interventional Imaging, Paris (France); Morel, Olivier; Barranger, Emmanuel [Hopital Lariboisiere AP-HP, Department of Obstetrics and Gynecology, Paris (France); Gayat, Etienne; Mebazaa, Alexandre [Hopital Lariboisiere AP-HP, Department of Anesthesiology and Intensive Care Medicine, Paris (France)


    To evaluate the role and efficacy of pelvic embolisation in the treatment of persistent postpartum haemorrhage after failed arterial ligation and to identify the complications of this procedure in this specific population. The clinical files and angiographic examinations of 12 consecutive women (mean age 32 years) who were treated with pelvic embolisation because of persistent, severe postpartum haemorrhage after failed arterial ligation were reviewed. Angiography revealed that persistent bleeding was due to incomplete arterial ligation (n = 4) or the presence of newly developed anastomotic routes (n = 8). In 11 women, pelvic embolisation stopped the bleeding. Hysterectomy was needed in one woman with retained placenta. Two complications due to pelvic embolisation, including leg ischaemia and transient sciatic nerve ischaemia, were identified, both after internal iliac artery ligation. In women with persistent postpartum haemorrhage after failed arterial ligation, pelvic embolisation is an effective treatment in most cases. However, embolisation of the anastomotic routes that contribute to persistent bleeding may result in ischaemic complications. These potential complications reaffirm that arterial ligation should not be the favoured option for postpartum haemorrhage and that special care must be given during pelvic embolisation after failed arterial ligation. (orig.)

  17. Recursive directional ligation by plasmid reconstruction allows rapid and seamless cloning of oligomeric genes. (United States)

    McDaniel, Jonathan R; Mackay, J Andrew; Quiroz, Felipe García; Chilkoti, Ashutosh


    This paper reports a new strategy, recursive directional ligation by plasmid reconstruction (PRe-RDL), to rapidly clone highly repetitive polypeptides of any sequence and specified length over a large range of molecular weights. In a single cycle of PRe-RDL, two halves of a parent plasmid, each containing a copy of an oligomer, are ligated together, thereby dimerizing the oligomer and reconstituting a functional plasmid. This process is carried out recursively to assemble an oligomeric gene with the desired number of repeats. PRe-RDL has several unique features that stem from the use of type IIs restriction endonucleases: first, PRe-RDL is a seamless cloning method that leaves no extraneous nucleotides at the ligation junction. Because it uses type IIs endonucleases to ligate the two halves of the plasmid, PRe-RDL also addresses the major limitation of RDL in that it abolishes any restriction on the gene sequence that can be oligomerized. The reconstitution of a functional plasmid only upon successful ligation in PRe-RDL also addresses two other limitations of RDL: the significant background from self-ligation of the vector observed in RDL, and the decreased efficiency of ligation due to nonproductive circularization of the insert. PRe-RDL can also be used to assemble genes that encode different sequences in a predetermined order to encode block copolymers or append leader and trailer peptide sequences to the oligomerized gene.

  18. Efficient DNA ligation in DNA-RNA hybrid helices by Chlorella virus DNA ligase. (United States)

    Lohman, Gregory J S; Zhang, Yinhua; Zhelkovsky, Alexander M; Cantor, Eric J; Evans, Thomas C


    Single-stranded DNA molecules (ssDNA) annealed to an RNA splint are notoriously poor substrates for DNA ligases. Herein we report the unexpectedly efficient ligation of RNA-splinted DNA by Chlorella virus DNA ligase (PBCV-1 DNA ligase). PBCV-1 DNA ligase ligated ssDNA splinted by RNA with kcat ≈ 8 x 10(-3) s(-1) and K(M) DNA ligase produced only 5'-adenylylated DNA with a 20-fold lower kcat and a K(M) ≈ 300 nM. The rate of ligation increased with addition of Mn(2+), but was strongly inhibited by concentrations of NaCl >100 mM. Abortive adenylylation was suppressed at low ATP concentrations (8, leading to increased product yields. The ligation reaction was rapid for a broad range of substrate sequences, but was relatively slower for substrates with a 5'-phosphorylated dC or dG residue on the 3' side of the ligation junction. Nevertheless, PBCV-1 DNA ligase ligated all sequences tested with 10-fold less enzyme and 15-fold shorter incubation times than required when using T4 DNA ligase. Furthermore, this ligase was used in a ligation-based detection assay system to show increased sensitivity over T4 DNA ligase in the specific detection of a target mRNA.

  19. Isolation and characterization of portal branch ligation-stimulated Hmga2-positive bipotent hepatic progenitor cells

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Hiroshi [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 B51, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Tagawa, Yoh-ichi, E-mail: [Frontier Research Center, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 B51, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Tamai, Miho [Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 B51, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Motoyama, Hiroaki [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Ogawa, Shinichiro [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); McEwen Center for Regenerative Medicine, University Health Network, 190 Elizabeth Street, Toronto, Ont., Canada M5G 2C4 (Canada); Soeda, Junpei; Nakata, Takenari; Miyagawa, Shinichi [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan)


    Research highlights: {yields} Hepatic progenitor cells were isolated from the portal branch-ligated liver of mice. {yields} Portal branch ligation-stimulated hepatic progenitor cells (PBLHCs) express Hmga2. {yields} PBLHCs have bidirectional differentiation capability in vitro. -- Abstract: Hepatic stem/progenitor cells are one of several cell sources that show promise for restoration of liver mass and function. Although hepatic progenitor cells (HPCs), including oval cells, are induced by administration of certain hepatotoxins in experimental animals, such a strategy would be inappropriate in a clinical setting. Here, we investigated the possibility of isolating HPCs in a portal branch-ligated liver model without administration of any chemical agents. A non-parenchymal cell fraction was prepared from the portal branch-ligated or non-ligated lobe, and seeded onto plates coated with laminin. Most of the cells died, but a small number were able to proliferate. These proliferating cells were cloned as portal branch ligation-stimulated hepatic cells (PBLHCs) by the limiting dilution method. The PBLHCs expressed cytokeratin19, albumin, and Hmga2. The PBLHCs exhibited metabolic functions such as detoxification of ammonium ions and synthesis of urea on Matrigel-coated plates in the presence of oncostatin M. In Matrigel mixed with type I collagen, the PBLHCs became rearranged into cystic and tubular structures. Immunohistochemical staining demonstrated the presence of Hmga2-positive cells around the interlobular bile ducts in the portal branch-ligated liver lobes. In conclusion, successful isolation of bipotent hepatic progenitor cell clones, PBLHCs, from the portal branch-ligated liver lobes of mice provides the possibility of future clinical application of portal vein ligation to induce hepatic progenitor cells.

  20. Comparative Study of Compensatory Liver Regeneration in a Rat Model: Portal Vein Ligation Only versus Sequential Ligation of the Portal Vein and Hepatic Artery

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Soo Young [Dept. of Pathology, Dongnam Institute of Radiological and Medical Sciences, Busan (Korea, Republic of); Jeon, Gyeong Sik [Dept. of Radiology, CHA Bundang Medical Center, College of Medicine, CHA University, Seongnam (Korea, Republic of); Lee, Byung Mo [Dept. of Surgery, Seoul Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of)


    To compare the volume change and the regenerative capacity between portal vein ligation (embolization) (PVL) and heterochronous PVL with hepatic artery ligation (HAL) in a rodent model. The animals were separated into three groups: group I, ligation of the left lateral and median portal vein branches; group II, completion of PVL, followed by ligation of the same branches of the hepatic artery after 48 h; control group, laparotomy without ligation was performed. Five rats from each group were sacrificed on 1, 3, 5, and 7 days after the operation. Volume change measurement, liver function tests and immunohistochemical analysis were performed. The volume of the nonligated lobe between groups I and II was not significantly different by day 5 and day 7. Mean alanine aminotransferase and total bilirubin levels were significantly higher in group II, while the albumin level was higher in group I. Both c-kit- and MIB-5-positive cells used in the activity detection of regeneration were more prevalent in group I on day 1, 3, and 5, with statistical significance. There was no operation related mortality. PVL alone is safe and effective in compensatory liver regeneration. Performing both PVL and HAL does not confer any additional benefits.

  1. A modified version of the digestion-ligation cloning method for more efficient molecular cloning. (United States)

    Gao, Song; Li, Yanling; Zhang, Jiannan; Chen, Hongman; Ren, Daming; Zhang, Lijun; An, Yingfeng


    Here we describe a modified version of the digestion-ligation approach for efficient molecular cloning. In comparison with the original method, the modified method has the additional steps of gel purification and a second ligation after the first ligation of the linearized vector and DNA insert. During this process, the efficiency and reproducibility could be significantly improved for both stick-end cloning and blunt-end cloning. As an improvement of the very important molecular cloning technique, this method may find a wide range of applications in bioscience and biotechnology.

  2. Real time monitoring of nucleic acids ligation based on molecular beacon

    Institute of Scientific and Technical Information of China (English)


    A novel method has been developed to monitor the nucleic acids ligation process. Molecular beacon was employed here to convert the ligation information into fluorescence signal quickly and quantitatively. This method provides effective and original approach to researching the dynamic ligation process and the interactions between nucleic acids and ligase. An analytical method for T4 DNA ligase based on this way has been built up with a linear detection range from 2.3×10?4 U/mL to 0.23 U/mL. It is rapid and sensitive to detect 2.8×10?5 U T4 DNA ligase in 10 min.

  3. Evaluation of small ligand-protein interaction by ligation reaction with DNA-modified ligand. (United States)

    Sugita, Rie; Mie, Masayasu; Funabashi, Hisakage; Kobatake, Eiry


    A method for the evaluation of interactions between protein and ligand using DNA-modified ligands, including signal enhancement of the DNA ligation reactions, is described. For proof of principle, a DNA probe modified by biotin was used. Two DNA probes were prepared with complementary sticky-ends. While one DNA probe was modified at the 5'-end of the sticky-end, the other was not modified. The probes could be ligated together by T4 DNA ligase along the strand without biotin modification. However, in the presence of streptavidin or anti-biotin Fab, the ligation reaction joining the two probes could not occur on either strand.

  4. Efficient DNA ligation in DNA–RNA hybrid helices by Chlorella virus DNA ligase


    Lohman, Gregory J. S.; Zhang, Yinhua; Zhelkovsky, Alexander M.; Cantor, Eric J.; Evans, Thomas C.


    Single-stranded DNA molecules (ssDNA) annealed to an RNA splint are notoriously poor substrates for DNA ligases. Herein we report the unexpectedly efficient ligation of RNA-splinted DNA by Chlorella virus DNA ligase (PBCV-1 DNA ligase). PBCV-1 DNA ligase ligated ssDNA splinted by RNA with kcat ≈ 8 x 10−3 s−1 and KM < 1 nM at 25°C under conditions where T4 DNA ligase produced only 5′-adenylylated DNA with a 20-fold lower kcat and a KM ≈ 300 nM. The rate of ligation increased with addition of M...

  5. Distributed feedback laser amplifiers combining the functions of amplifiers and channel filters

    DEFF Research Database (Denmark)

    Wang, Z.; Durhuus, T.; Mikkelsen, Benny;


    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....

  6. Amplified spontaneous emission and its restraint in a terawatt Ti:sapphire amplifier

    Institute of Scientific and Technical Information of China (English)


    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.

  7. The new LM-PCR/shifter method for the genotyping of microorganisms based on the use of a class IIS restriction enzyme and ligation mediated PCR. (United States)

    Krawczyk, Beata; Leibner-Ciszak, Justyna; Stojowska, Karolina; Kur, Józef


    This study details and examines a novel ligation-mediated polymerase chain reaction (LM-PCR) method. Named the LM-PCR/Shifter, it relies on the use of a Class IIS restriction enzyme giving restriction fragments with different 4-base, 5' overhangs, this being the Shifter, and the ligation of appropriate oligonucleotide adapters. A sequence of 4-base, 5' overhangs of the adapter and a 4- base sequence of the 3' end of the primer(s) determine a subset of the genomic restriction fragments, which are amplified by PCR. The method permits the differentiation of bacterial species strains on the basis of the different DNA band patterns obtained after electrophoresis in polyacrylamide gels stained with ethidium bromide and visualized in UV light. The usefulness of the LM-PCR/ Shifter method for genotyping is analyzed by a comparison with the restriction endonuclease analysis of chromosomal DNA by the pulsed-field gel electrophoresis (REA-PFGE) and PCR melting profile (PCR MP) methods for isolates of clinical origin. The clustering of the LM-PCR/Shifter fingerprinting data matched those of the REA-PFGE and PCR MP methods. We found that the LM-PCR/Shifter is rapid, and offers good discriminatory power and excellent reproducibility, making it a method that may be effectively applied in epidemiological studies.

  8. Simultaneous detection of genetically modified organisms by multiplex ligation-dependent genome amplification and capillary gel electrophoresis with laser-induced fluorescence. (United States)

    García-Cañas, Virginia; Mondello, Monica; Cifuentes, Alejandro


    In this work, an innovative method useful to simultaneously analyze multiple genetically modified organisms is described. The developed method consists in the combination of multiplex ligation-dependent genome dependent amplification (MLGA) with CGE and LIF detection using bare-fused silica capillaries. The MLGA process is based on oligonucleotide constructs, formed by a universal sequence (vector) and long specific oligonucleotides (selectors) that facilitate the circularization of specific DNA target regions. Subsequently, the circularized target sequences are simultaneously amplified with the same couple of primers and analyzed by CGE-LIF using a bare-fused silica capillary and a run electrolyte containing 2-hydroxyethyl cellulose acting as both sieving matrix and dynamic capillary coating. CGE-LIF is shown to be very useful and informative for optimizing MLGA parameters such as annealing temperature, number of ligation cycles, and selector probes concentration. We demonstrate the specificity of the method in detecting the presence of transgenic DNA in certified reference and raw commercial samples. The method developed is sensitive and allows the simultaneous detection in a single run of percentages of transgenic maize as low as 1% of GA21, 1% of MON863, and 1% of MON810 in maize samples with signal-to-noise ratios for the corresponding DNA peaks of 15, 12, and 26, respectively. These results demonstrate, to our knowledge for the first time, the great possibilities of MLGA techniques for genetically modified organisms analysis.

  9. Self-pulsation in Raman fiber amplifiers

    DEFF Research Database (Denmark)

    Pedersen, Martin Erland Vestergaard; Ott, Johan Raunkjær; Rottwitt, Karsten


    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....


    DEFF Research Database (Denmark)


    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...

  11. Digital quantification of rolling circle amplified single DNA molecules in a resistive pulse sensing nanopore. (United States)

    Kühnemund, M; Nilsson, M


    Novel portable, sensitive and selective DNA sensor methods for bio-sensing applications are required that can rival conventionally used non-portable and expensive fluorescence-based sensors. In this paper, rolling circle amplification (RCA) products are detected in solution and on magnetic particles using a resistive pulse sensing (RPS) nanopore. Low amounts of DNA molecules are detected by padlock probes which are circularized in a strictly target dependent ligation reaction. The DNA-padlock probe-complex is captured on magnetic particles by sequence specific capture oligonucleotides and amplified by a short RCA. Subsequent RPS analysis is used to identify individual particles with single attached RCA products from blank particles. This proof of concept opens up for a novel non-fluorescent digital DNA quantification method that can have many applications in bio-sensing and diagnostic approaches.

  12. Ultrafast disk lasers and amplifiers (United States)

    Sutter, Dirk H.; Kleinbauer, Jochen; Bauer, Dominik; Wolf, Martin; Tan, Chuong; Gebs, Raphael; Budnicki, Aleksander; Wagenblast, Philipp; Weiler, Sascha


    Disk lasers with multi-kW continuous wave (CW) output power are widely used in manufacturing, primarily for cutting and welding applications, notably in the automotive industry. The ytterbium disk technology combines high power (average and/or peak power), excellent beam quality, high efficiency, and high reliability with low investment and operating costs. Fundamental mode picosecond disk lasers are well established in micro machining at high throughput and perfect precision. Following the world's first market introduction of industrial grade 50 W picosecond lasers (TruMicro 5050) at the Photonics West 2008, the second generation of the TruMicro series 5000 now provides twice the average power (100 W at 1030 nm, or 60 W frequency doubled, green output) at a significantly reduced footprint. Mode-locked disk oscillators achieve by far the highest average power of any unamplified lasers, significantly exceeding the 100 W level in laboratory set-ups. With robust long resonators their multi-microjoule pulse energies begin to compete with typical ultrafast amplifiers. In addition, significant interest in disk technology has recently come from the extreme light laser community, aiming for ultra-high peak powers of petawatts and beyond.

  13. Small gold nanoparticles for interfacial Staudinger-Bertozzi ligation. (United States)

    Gobbo, Pierangelo; Luo, Wilson; Cho, Sung Ju; Wang, Xiaoxiao; Biesinger, Mark C; Hudson, Robert H E; Workentin, Mark S


    Small gold nanoparticles (AuNPs) that possess interfacial methyl-2-(diphenylphosphino)benzoate moieties have been successfully synthesized (Staudinger-AuNPs) and characterized by multi-nuclear MR spectroscopy, transmission electron microscopy (TEM), UV-Vis spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy (XPS). In particular, XPS was remarkably sensitive for characterization of the novel nanomaterial, and in furnishing proof of its interfacial reactivity. These Staudinger-AuNPs were found to be stable to the oxidation of the phosphine center. The reaction with benzyl azide in a Staudinger-Bertozzi ligation, as a model system, was investigated using (31)P NMR spectroscopy. This demonstrated that the interfacial reaction was clean and quantitative. To showcase the potential utility of these Staudinger-AuNPs in bioorganic chemistry, a AuNP bioconjugate was prepared by reacting the Staudinger-AuNPs with a novel azide-labeled CRGDK peptide. The CRGDK peptide could be covalently attached to the AuNP efficiently, chemoselectively, and with a high loading.

  14. Expanded utility of the native chemical ligation reaction. (United States)

    Yeo, Dawn S Y; Srinivasan, Rajavel; Chen, Grace Y J; Yao, Shao Q


    The post-genomic era heralds a multitude of challenges for chemists and biologists alike, with the study of protein functions at the heart of much research. The elucidation of protein structure, localization, stability, post-translational modifications, and protein interactions will steadily unveil the role of each protein and its associated biological function in the cell. The push to develop new technologies has necessitated the integration of various disciplines in science. Consequently, the role of chemistry has never been so profound in the study of biological processes. By combining the strengths of recombinant DNA technology, protein splicing, organic chemistry, and the chemoselective chemistry of native chemical ligation, various strategies have been successfully developed and applied to chemoselectively label proteins, both in vitro and in live cells, with biotin, fluorescent, and other small molecule probes. The site-specific incorporation of molecular entities with unique chemical functionalities in proteins has many potential applications in chemical and biological studies of proteins. In this article, we highlight recent progress of these strategies in several areas related to proteomics and chemical biology, namely, in vitro and in vivo protein biotinylation, protein microarray technologies for large-scale protein analysis, and live-cell bioimaging.

  15. Laparoscopic ligation of varicoceles: an anatomically superior operation. (United States)

    al-Shareef, Z. H.; Koneru, S. R.; al-Tayeb, A.; Shehata, Z. M.; Aly, T. F.; Basyouni, A.


    Since December 1991, 25 consecutive symptomatic male patients with 26 varicoceles were treated by laparoscopic ligation of internal spermatic veins under general anaesthesia. Twenty-one patients had either scrotal discomfort or painful swelling and four patients presented with infertility. The mean follow-up period is 5 months (range 3 weeks to 9 months). The procedure has provided a satisfactory outcome in 19 out of 21 patients (90.5%) with scrotal symptoms. Of the four patients presenting with infertility due to oligospermia, three had significantly elevated sperm counts at 3 months which resulted in one pregnancy. So far there has been no recurrence of the varicocele. The main potential advantage of the laparoscopic approach is better visualisation of the anatomy, especially the testicular artery and the collateral venous circulation at the level of the internal inguinal ring. In addition to being less invasive with implied benefits, the endoscopic procedure has enabled identification of multiple veins in 22 out of 26 (84.6%) varicoceles in our series. PMID:8166797

  16. Design and performance of the beamlet amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Erlandson, A.C.; Rotter, M.D.; Frank, M.D.; McCracken, R.W.


    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.

  17. Amplified OTDR systems for multipoint corrosion monitoring. (United States)

    Nascimento, Jehan F; Silva, Marcionilo J; Coêlho, Isnaldo J S; Cipriano, Eliel; Martins-Filho, Joaquim F


    We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations.

  18. Amplified OTDR Systems for Multipoint Corrosion Monitoring

    Directory of Open Access Journals (Sweden)

    Joaquim F. Martins-Filho


    Full Text Available We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations.

  19. Detection of Non-Amplified Genomic DNA

    CERN Document Server

    Corradini, Roberto


    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...

  20. 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. 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 PSRR...

  1. Chemoselective modifications for the traceless ligation of thioamide-containing peptides and proteins. (United States)

    Wang, Yanxin J; Szantai-Kis, D Miklos; Petersson, E James


    Thioamides are single-atom substitutions of canonical amide bonds, and have been proven to be versatile and minimally perturbing probes in protein folding studies. Previously, our group showed that thioamides can be incorporated into proteins by native chemical ligation (NCL) with Cys as a ligation handle. In this study, we report the expansion of this strategy into non-Cys ligation sites, utilizing radical initiated desulfurization to "erase" the side chain thiol after ligation. The reaction exhibited high chemoselectivity against thioamides, which can be further enhanced with thioacetamide as a sacrificial scavenger. As a proof-of-concept example, we demonstrated the incorporation of a thioamide probe into a 56 amino acid protein, the B1 domain of Protein G (GB1). Finally, we showed that the method can be extended to β-thiol amino acid analogs and selenocysteine.

  2. Chemical ligation methods for the tagging of DNA-encoded chemical libraries. (United States)

    Keefe, Anthony D; Clark, Matthew A; Hupp, Christopher D; Litovchick, Alexander; Zhang, Ying


    The generation of DNA-encoded chemical libraries requires the unimolecular association of multiple encoding oligonucleotides with encoded chemical entities during combinatorial synthesis processes. This has traditionally been achieved using enzymatic ligation. We discuss a range of chemical ligation methods that provide alternatives to enzymatic ligation. These chemical ligation methods include the generation of modified internucleotide linkages that support polymerase translocation and other modified linkages that while not supporting the translocation of polymerases can also be used to generate individual cDNA molecules containing encoded chemical information specifying individual library members. We also describe which of these approaches have been successfully utilized for the preparation of DNA-encoded chemical libraries and those that were subsequently used for the discovery of inhibitors.

  3. Heated oligonucleotide ligation assay (HOLA): an affordable single nucleotide polymorphism assay. (United States)

    Black, W C; Gorrochotegui-Escalante, N; Duteau, N M


    Most single nucleotide polymorphism (SNP) detection requires expensive equipment and reagents. The oligonucleotide ligation assay (OLA) is an inexpensive SNP assay that detects ligation between a biotinylated "allele-specific detector" and a 3' fluorescein-labeled "reporter" oligonucleotide. No ligation occurs unless the 3' detector nucleotide is complementary to the SNP nucleotide. The original OLA used chemical denaturation and neutralization. Heated OLA (HOLA) instead uses a thermal stable ligase and cycles of denaturing and hybridization for ligation and SNP detection. The cost per genotype is approximately US$1.25 with two-allele SNPs or approximately US$1.75 with three-allele SNPs. We illustrate the development of HOLA for SNP detection in the Early Trypsin and Abundant Trypsin loci in the mosquito Aedes aegypti (L.) and at the a-glycerophosphate dehydrogenase locus in the mosquito Anopheles gambiae s.s.

  4. Common Carotid Artery Ligation to Minimize Blood Loss During Oral and Maxillofacial Surgery. (United States)

    Goodman, Alice E; Goodman, Andrew R


    Oral and maxillofacial surgery in veterinary medicine carries the risk of severe hemorrhage due to the great vascular supply of the head. Temporary hemostasis can be achieved with the application of pressure or hemostatic agents, but more definitive treatment may be needed to ensure bleeding will not resume once the patient is awake and normotensive. (1 , 2) Actively bleeding vessels encountered during maxillofacial surgery may be inaccessible, and vessels may recoil into bone, sometimes preventing definitive ligation. These scenarios may require ligation of the common carotid artery. (1) The purpose of this paper is to describe how to perform ligation of the common carotid artery in a step-by-step fashion. Both temporary and permanent ligation techniques are described.

  5. Interrupting Rivaling Access-flow with Nonsurgical Image-guided ligation: the "IRANI" Procedure. (United States)

    Cui, Jie; Freed, Robert; Liu, Fengyong; Irani, Zubin


    The presence of collateral veins is one of the most common causes of fistula failure to mature. The traditional approach to eliminate collateral vessel flow is coil embolization under fluoroscopy or surgical cut down and branch vessel ligation. However, both approaches are expensive and time consuming. Here, we described an image-guided nonsurgical method to ligate collateral veins. The collateral veins were ligated using Hawkins-Akins needle under ultrasound guidance. The average time for one ligation procedure was 17 minutes. There was a significant increase of blood flow in the venous outflow postligation procedure. Four weeks postprocedure ultrasound demonstrated occlusion of the target vessels. This procedure was well tolerated without major complications. In summary, the novel procedure described here offers an image-guided nonsurgical approach for collateral vein occlusion.

  6. Generating site-specifically modified proteins via a versatile and stable nucleophilic carbon ligation. (United States)

    Kudirka, Romas; Barfield, Robyn M; McFarland, Jesse; Albers, Aaron E; de Hart, Gregory W; Drake, Penelope M; Holder, Patrick G; Banas, Stefanie; Jones, Lesley C; Garofalo, Albert W; Rabuka, David


    There is a need for facile chemistries that allow for chemo- and regioselectivity in bioconjugation reactions. To address this need, we are pioneering site-specific bioconjugation methods that use formylglycine as a bioorthogonal handle on a protein surface. Here we introduce aldehyde-specific bioconjugation chemistry, the trapped-Knoevenagel ligation. The speed and stability of the trapped-Knoevenagel ligation further advances the repertoire of aldehyde-based bioconjugations and expands the toolbox for site-specific protein modifications. The trapped-Knoevenagel ligation reaction can be run at near neutral pH in the absence of catalysts to produce conjugates that are stable under physiological conditions. Using this new ligation, we generated an antibody-drug conjugate that demonstrates excellent efficacy in vitro and in vivo.

  7. Nonenzymatic ligation of an RNA oligonucleotide analyzed by atomic force microscopy. (United States)

    Pino, Samanta; Biasiucci, Mariano; Scardamaglia, Mattia; Gigli, Giuseppe; Betti, Maria Grazia; Mariani, Carlo; Di Mauro, Ernesto


    The products of ligation reaction of a 24 nucleotides long PolyA RNA adsorbed on mica were observed by atomic force microscopy. The occurrence of oligonucleotides at different degrees of polymerization has been quantitatively studied before and after ligation reaction. The microscopy images at the nanoscale show that nonenzymatic ligation of pristine RNA monomers results in the formation of supramolecular aggregates, with prevalence of dimers and tetramers. Analytical conditions were defined allowing the identification, the quantitative evaluation, and their distribution after ligation reaction, also providing an estimate of the degree of hydration of the objects. Such investigation is of particular biological relevance and provides the simplest yet model system for direct investigation of RNA reactions by advanced microscopy.

  8. Comparison of frictional resistance of esthetic and semi-esthetic self-ligating brackets

    Directory of Open Access Journals (Sweden)

    M S Kannan


    Full Text Available Aim: The frictional resistance encountered during sliding mechanics has been well established in the orthodontic literature, and it consists of complex interactions between the bracket, archwire, and method of ligation the claim of reduced friction with self-ligating brackets is often cited as a primary advantage over conventional brackets. This study was done to compare and evaluate the frictional forces generated between fully esthetic brackets and semi-aesthetic self-ligating brackets, which are of passive form and SEM (scanning electron microscope study of the Brackets after Frictional evaluation. Materials and Methods: Two types of self-ligating esthetic brackets, Damon clear (Ormco made of fully ceramic and Opal (Ultradent Products, USA and, Two types of self-ligating semi-esthetic brackets, Clarity SL (3M Unitek and Damon 3 (Ormco both of which are made of ceramic with metal slot. Arch wires with different dimensions and quality 17 × 25, 19 × 25 Titanium Molybdenum Alloy (TMA and 17 × 25, 19 × 25 stainless steel that came from plain strands of wire were used for frictional comparison test. The brackets used in this study had 0.022 × 0.028 inch slot. Results: The statistical tests showed significantly smaller amount of kinetic frictional forces is generated by Damon 3 (semi-esthetic self-ligating brackets. For each wire used, Damon 3 displayed significantly lower frictional forces (P ≤ 0.05 than any of the self-ligating system, followed by Opal (fully esthetic self-ligating brackets which generated smaller amount of frictional forces but relatively on the higher side when compared with Damon 3. Damon clear (fully esthetic self-ligating brackets generated the maximum amount of kinetic forces with all types of wire dimensions and properties when compared to the other three types of self-ligating system. Clarity SL (semi-esthetic self-ligating brackets generated smaller amount of frictional forces when compared with Damon clear and

  9. Can 5-aminosalicylic acid suppository decrease the pain after rectal band ligation?

    Institute of Scientific and Technical Information of China (English)

    Burcak Kayhan; Digdem Ozer; Meral Akdogan; Ersan Ozaslan; Osman Yuksel


    AIM: To investigate the effect of 5-aminosalicylic acid (5-ASA) suppositories on rectal band ligation-induced pain.METHODS: Sixty patients were randomized into two treatment groups.RESULTS: Our results showed that there was no difference between 5-ASA suppository group and the control group for pain control.CONCLUSION: 5-ASA may be an alternative treatment for hemorrhoids; however, it does not affect the rectal band ligation-induced pain.

  10. Hypermutable ligation of plasmid DNA ends in cells from patients with Werner syndrome. (United States)

    Rünger, T M; Bauer, C; Dekant, B; Möller, K; Sobotta, P; Czerny, C; Poot, M; Martin, G M


    Werner Syndrome is a rare autosomal recessive disorder characterized by an increased cancer risk and by symptoms suggestive of premature aging. Cells from these patients demonstrate a typical pattern of chromosomal instability and a spontaneous hypermutability with a high rate of unusually large deletions. We have studied the in vivo DNA ligation in three lymphoblast cell lines from Werner syndrome patients and three from normal donors. In our host cell ligation assay we transfected linearized plasmid pZ189 and measured the amount of plasmid DNA ends rejoined by these host cells as the ability of the recovered plasmid to transform bacteria. A mutagenesis marker gene close to the ligation site allowed screening for mutations. Subsequent mutation analysis provided information about the accuracy of the ligation process. The cells from Werner syndrome patients were as effective as normal cells in ligating DNA ends. However, mutation analysis revealed that the three Werner syndrome cell lines introduced 2.4-4.6 times more mutations (p < 0.001) than the normal cell lines during ligation of the DNA ends: the mutation rates were 69.4, 97.2, and 58.7%, as compared to 23.6, 21.7, and 24.4% in the normal cell lines. These increased mutation frequencies in plasmids ligated during passage through Werner syndrome cells were mainly due to a significant (p < 0.001) increase in deletions. This error-prone DNA ligation might be responsible for the spontaneous hypermutability and the genomic instability in Werner syndrome cells and related to the apparently accelerated aging and high cancer risk in affected patients.

  11. Effect of ZVAD-fmk on hepatocyte apoptosis after bile duct ligation in rat

    Institute of Scientific and Technical Information of China (English)

    Shyr-Ming Sheen-Chen; Hsin-Tsung Ho; Wei-Jen Chen; Hock-Liew Eng


    AIM: Retention and accumulation of toxic hydrophobic bile salts within hepatocyte may cause hepatocyte toxicity by inducing apoptosis. Apoptosis is a pathway of cell death orchestrated by a family of proteases called caspases. Z-ValAla-Asp (OMe)-fluoromethyl ketone (ZVAD-fmk) is a cellpermeable irreversible inhibitor of caspase. The purpose of this study was to evaluate the possible effect of ZVAD-fmk on hepatocyte apoptosis after bile duct ligation in the rat.METHODS: Male Sprague-Dawley rats, weighing 250-300 g,were randomized to five groups of five rats each. Group 1 underwent common bile duct ligation and simultaneous treatment with ZVAD-fmk (dissolved in dimethylsulfoxide (DMSO)). Group 2 underwent common bile duct ligation and simultaneous treatment with Z-Phe-Ala-fluoromethyl ketone ( ZFA-fmk, dissolved in DMSO). Group 3 underwent sham operation and simultaneous treatment with the same amount of DMSO. Group 4 underwent sham operation and simultaneous treatment with the same amount of normal saline. Group 5 underwent common bile duct ligation without other manipulation. After three days, liver tissue was harvested for histopathologic analysis and measurements of apoptosis.RESULTS: When compared with sham operation, common bile duct ligation significantly increased hepatocyte apoptosis (P= 0.008) and ductular proliferation (P= 0.007).ZVAD-fmk significantly diminished the increased hepatocyte apoptosis and ductular proliferation after common bile duct ligation (P = 0.008 and P = 0.007, respectively). ZFA did not show the same effects.CONCLUSION: Hepatocyte apoptosis and ductular proliferation significantly increased after common bile duct ligation. ZVAD-fmk effectively diminished the increased hepatocyte apoptosis and ductular proliferation after common bile duct ligation, whereas ZFA-fmk did not.

  12. Is Previous Tubal Ligation a Risk Factor for Hysterectomy because of Abnormal Uterine Bleeding?


    Sanam Moradan; Raheb Gorbani


    Objectives: Post tubal ligation syndrome (PTLS) is a term used to describe a variety of post tubal ligation side effects or symptoms. These include increased menstrual bleeding and hysterectomy. Whether or not post tubal syndrome is a real entity, it has been a subject of controversy in the medical literature for decades. Numerous studies have reported conflicting conclusions about these symptoms. In this study the incidence of hysterectomy for bleeding disorders among sterilized women was co...

  13. Cross-catalytic peptide nucleic acid (PNA) replication based on templated ligation

    DEFF Research Database (Denmark)

    Singhal, Abhishek; Nielsen, Peter E


    We report the first PNA self-replicating system based on template directed cross-catalytic ligation, a process analogous to biological replication. Using two template PNAs and four pentameric precursor PNAs, all four possible carbodiimide assisted amide ligation products were detected and identif...... oligonucleotides are feasible, thereby strengthening the foundation for the discussion of a possible role for PNA (like) genetic material in the prebiotic evolution of life and lay the ground for further studies into evolution of such potentially prebiotic systems....

  14. Superficial Dorsal Vein Injury/Thrombosis Presenting as False Penile Fracture Requiring Dorsal Venous Ligation

    Directory of Open Access Journals (Sweden)

    Arash Rafiei, MD


    Conclusion: Early exploration of patients with suspected penile fracture provides excellent results with maintenance of erectile function. Also, in the setting of dorsal vein thrombosis, ligation preserves the integrity of the penile tissues and avoids unnecessary complications from conservative management. Rafiei A, Hakky TS, Martinez D, Parker J, and Carrion R. Superficial dorsal vein injury/thrombosis presenting as false penile fracture requiring dorsal venous ligation. Sex Med 2014;2:182–185.

  15. Synthesis of cysteine-rich peptides by native chemical ligation without use of exogenous thiols. (United States)

    Tsuda, Shugo; Yoshiya, Taku; Mochizuki, Masayoshi; Nishiuchi, Yuji


    Native chemical ligation (NCL) performed without resorting to the use of thiol additives was demonstrated to be an efficient and effective procedure for synthesizing Cys-rich peptides. This method using tris(2-carboxyethyl)phosphine (TCEP) as a reducing agent facilitates the ligation reaction even at the Thr-Cys or Ile-Cys site and enables one-pot synthesis of Cys-rich peptides throughout NCL and oxidative folding.

  16. Combining ligation reaction and capillary gel electrophoresis to obtain reliable long DNA probes. (United States)

    García-Cañas, Virginia; Mondello, Monica; Cifuentes, Alejandro


    New DNA amplification methods are continuously developed for sensitive detection and quantification of specific DNA target sequences for, e.g. clinical, environmental or food applications. These new applications often require the use of long DNA oligonucleotides as probes for target sequences hybridization. Depending on the molecular technique, the length of DNA probes ranges from 40 to 450 nucleotides, solid-phase chemical synthesis being the strategy generally used for their production. However, the fidelity of chemical synthesis of DNA decreases for larger DNA probes. Defects in the oligonucleotide sequence result in the loss of hybridization efficiency, affecting the sensitivity and selectivity of the amplification method. In this work, an enzymatic procedure has been developed as an alternative to solid-phase chemical synthesis for the production of long oligonucleotides. The enzymatic procedure for probe production was based on ligation of short DNA sequences. Long DNA probes were obtained from smaller oligonucleotides together with a short sequence that acts as bridge stabilizing the molecular complex for DNA ligation. The ligation reactions were monitored by capillary gel electrophoresis with laser-induced fluorescence detection (CGE-LIF) using a bare fused-silica capillary. The capillary gel electrophoresis-LIF method demonstrated to be very useful and informative for the characterization of the ligation reaction, providing important information about the nature of some impurities, as well as for the fine optimization of the ligation conditions (i.e. ligation cycles, oligonucleotide and enzyme concentration). As a result, the yield and quality of the ligation product were highly improved. The in-lab prepared DNA probes were used in a novel multiplex ligation-dependent genome amplification (MLGA) method for the detection of genetically modified maize in samples. The great possibilities of the whole approach were demonstrated by the specific and sensitive

  17. Meta-analysis: banding ligation and medical interventions for the prevention of rebleeding from oesophageal varices

    DEFF Research Database (Denmark)

    Thiele, Maja; Krag, A; Rohde, Ulrich;


    In patients with oesophageal varices, the combination of endoscopic variceal ligation (EVL) and medical therapy is recommended as standard of care for prevention of rebleeding. The results of previous meta-analyses on this topic are equivocal.......In patients with oesophageal varices, the combination of endoscopic variceal ligation (EVL) and medical therapy is recommended as standard of care for prevention of rebleeding. The results of previous meta-analyses on this topic are equivocal....

  18. Measuring Optimal Length of the Amplifying Fiber in Different Working Conditions of the Amplifier

    Directory of Open Access Journals (Sweden)

    Radek Poboril


    Full Text Available The aim of this article is to highlight possible unwanted behaviour of an EDFA optical amplifier during temperature changes. After a brief introduction dealing with amplifiers and doped fibers in general we focus on the assembly of our own EDFA amplifier with standard construction and the IsoGain I-6 amplifying fiber, and on the parameters of its individual components. Since an erbium doped fiber has usually no direct thermal stabilization, temperature changes can affect performance of the entire amplifier. The next part of the article therefore describes the impacts of such changes on behaviour of our amplifier. At the very end we performed a measurement of the amplifier deployed in the actual WDM-PON the description of which can be found in the last chapter.

  19. Blood flow changes after unilateral carotid artery ligation monitored by optical coherence tomography (United States)

    Ma, Yushu; Liang, Chengbo; Suo, Yanyan; Zhao, Yuqian; Wang, Yi; Xu, Tao; Wang, Ruikang; Ma, Zhenhe


    Unilateral carotid artery ligation which could induce adaptive improvement is a classic model that has been widely used to study pathology of ischemic disease. In those studies, blood flow is an important parameter to characterize the ischemia. Optical coherence tomography (OCT) is a powerful imaging modality which can provide depth resolved images in biological tissue with high spatial and temporal resolution. SPF rats was anesthetized with isoflurane and divided into two groups. In first group, bilateral carotid artery was surgically exposed, and then left carotid artery was ligated. Blood flow changes of the contralateral carotid artery was monitored using high speed spectral domain optical coherence tomography, including the absolute flow velocity and the flow volume. In the other group, skull window was opened at the ipsilateral cerebral cortex of ligation and blood supply of small artery was measured before and after the ligation. The measured results demonstrate the blood supply compensation process after unilateral carotid artery ligation. With the superiority of high resolution, OCT is an effective technology in monitoring results of carotid artery after ligation.

  20. Cholestasis progression effects on long-term memory in bile duct ligation rats

    Directory of Open Access Journals (Sweden)

    Nasrin Hosseini


    Full Text Available Background : There is evidence that cognitive functions are affected by some liver diseases such as cholestasis. Bile duct ligation induces cholestasis as a result of impaired liver function and cognition. This research investigates the effect of cholestasis progression on memory function in bile duct ligation rats. Materials and Methods: Male Wistar rats were randomly divided into five groups, which include: control group for BDL-7, control group for BDL-21, sham group (underwent laparotomy without bile duct ligation, BDL-7 group (7 days after bile duct ligation, and BDL-21 group (21 days after bile duct ligation. Step-through passive avoidance test was employed to examine memory function. In all groups, short-term (7 days after foot shock and long-term memories (21 days after foot shock were assessed. Results: Our results showed that liver function significantly decreased with cholestasis progression (P < 0.01. Also our findings indicated BDL-21 significantly impaired acquisition time (P < 0.05. Memory retrieval impaired 7 (P < 0.05 and 21 days (P < 0.001 after foot shock in BDL-7 and BDL-21 groups, respectively. Conclusion: Based on these findings, liver function altered in cholestasis and memory (short-term and long-term memory impaired with cholestasis progression in bile duct ligation rats. Further studies are needed to better insight the nature of progression of brain damage in cholestatic disease.

  1. An efficient ligation reaction promoted by a Varkud Satellite ribozyme with extended 5'- and 3'-termini. (United States)

    Jones, F D; Ryder, S P; Strobel, S A


    The Neurospora Varkud Satellite (VS) RNA is capable of promoting a reversible self-cleavage reaction important for its replication pathway. In vivo the VS RNA performs a cis-cleavage reaction to generate monomeric length transcripts that are subsequently ligated to produce circular VS RNA. The predominant form of VS RNA observed in vivo is the closed circular form, though minimal VS ribozyme self-cleavage constructs lack detectable ligation activity. MFOLD analysis of the entire VS RNA sequence revealed an extended region 5' and 3' of the minimal self-cleaving region that could anneal to form a complementary helix, which we have termed helix 7. In full-length VS RNA, this helix appears to span over 40 bp of sequence and brings the 5'- and 3'-ends of the RNA into proximity for the ligation reaction. Here we report a variant of the VS ribozyme with an extended 5'- and 3'-terminus capable of forming a truncated helix 7 that promotes the ligation reaction in vitro. Through mutation and selection of this RNA we have identified a ribozyme containing two point mutations in the truncated helix 7 that ligates with >70% efficiency. These results show that an additional helical element absent in current VS ribozyme constructs is likely to be important for the ligation activity of VS RNA.

  2. Ligation reaction specificities of an NAD(+)-dependent DNA ligase from the hyperthermophile Aquifex aeolicus. (United States)

    Tong, J; Barany, F; Cao, W


    An NAD(+)-dependent DNA ligase from the hyperthermophilic bacterium Aquifex aeolicus was cloned, expressed in Escherichia coli and purified to homogeneity. The enzyme is most active in slightly alkaline pH conditions with either Mg(2+)or Mn(2+)as the metal cofactor. Ca(2+)and Ni(2+)mainly support formation of DNA-adenylate intermediates. The catalytic cycle is characterized by a low k (cat)value of 2 min(-1)with concomitant accumulation of the DNA - adenylate intermediate when Mg(2+)is used as the metal cofactor. The ligation rates of matched substrates vary by up to 4-fold, but exhibit a general trend of T/A ligation reaction is reaffirmed by results from 1 nt insertions on either the 3'- or 5'-side of the nick. Furthermore, most of the unligatable 3' mismatched base pairs prohibit formation of the DNA-adenylate intermediate, indicating that the substrate adenylation step is also a control point for ligation fidelity. Unlike previously studied ATP ligases, gapped substrates cannot be ligated and intermediate accumulation is minimal, suggesting that complete elimination of base pair complementarity on one side of the nick affects substrate adenylation on the 5'-side of the nick junction. Relationships among metal cofactors, ligation products and intermediate, and ligation fidelity are discussed.

  3. Electrochemical detection of point mutation based on surface ligation reaction and biometallization. (United States)

    Zhang, Peng; Chu, Xia; Xu, Xiangmin; Shen, Guoli; Yu, Ruqin


    A highly sensitive electrochemical method for point mutation detection based on surface enzymatic ligation reaction and biometallization is demonstrated. In this method the surface-immobilized allele-specific probe, complementary to the mutant target, undergoes allele-specific ligation with the 5'-phosphorylated ligation probe in the presence of the mutant oligonucleotide target and E. coli DNA ligase. If there is an allele mismatch, no ligation takes place. After thermal treatment at 90 degrees C, the formed duplex melts apart, which merely allows the ligation product to remain on the electrode surface. Then, biotinylated detection probes hybridize with the ligation product. With the binding of streptavidin-alkaline phosphatase (SA-ALP) to the biotinylated probes, a non-reductive substrate of alkaline phosphatase, ascorbic acid 2-phosphate (AA-P), can be converted into ascorbic acid (AA) at the electrode surface. Silver ions in solution are then reduced by AA, resulting in the deposition of silver metal onto the electrode surface. Linear sweep voltammetry (LSV) is used to detect the amount of deposited silver. The proposed approach has been successfully implemented for the identification of single base mutation in codon 12 of K-ras oncogene target with a detection limit of 80fM, demonstrating that this method provides a highly specific, sensitive and cost-efficient approach for point mutation detection.

  4. Insights into the mechanism and catalysis of the native chemical ligation reaction. (United States)

    Johnson, Erik C B; Kent, Stephen B H


    Native chemical ligation of unprotected peptide segments involves reaction between a peptide-alpha-thioester and a cysteine-peptide, to yield a product with a native amide bond at the ligation site. Peptide-alpha-thioalkyl esters are commonly used because of their ease of preparation. These thioalkyl esters are rather unreactive so the ligation reaction is catalyzed by in situ transthioesterification with thiol additives. The most common thiol catalysts used to date have been either a mixture of thiophenol/benzyl mercaptan, or the alkanethiol MESNA. Despite the use of these thiol catalysts, ligation reactions typically take 24-48 h. To gain insight into the mechanism of native chemical ligaton and in order to find a better catalyst, we investigated the use of a number of thiol compounds. Substituted thiophenols with pK(a) > 6 were found to best combine the ability to exchange rapidly and completely with thioalkyl esters, and to then act as effective leaving groups in reaction of the peptide-thioester with the thiol side chain of a cysteine-peptide. A highly effective and practical catalyst was (4-carboxylmethyl)thiophenol ('MPAA'), a nonmalodorous, water-soluble thiol. Use of MPAA gave an order of magnitude faster reaction in model studies of native chemical ligation and in the synthesis of a small protein, turkey ovomucoid third domain (OMTKY3). MPAA should find broad use in native chemical ligation and in the total synthesis of proteins.

  5. Effects of 2'-O-methyl nucleotide on ligation capability of T4 DNA ligase. (United States)

    Zhao, Bin; Tong, Zhaoxue; Zhao, Guojie; Mu, Runqing; Shang, Hong; Guan, Yifu


    To further understand the ligation mechanism, effects of 2'-O-methyl nucleotide (2'-OMeN) on the T4 DNA ligation efficiency were investigated. Fluorescence resonance energy transfer assay was used to monitor the nick-joining process by T4 DNA ligase. Results showed that substitutions at 5'- and 3'-ends of the nick decreased the ligation efficiency by 48.7% ± 6.7% and 70.6% ± 4.0%, respectively. Substitutions at both 5'- and 3'-ends decreased the ligation efficiency by 76.6% ± 1.3%. Corresponding kinetic parameters, Vmax, Km, and kcat, have been determined in each case by using the Michaelis-Menten equation. The kinetic data showed that the 2'-OMeN substitutions reduced the maximal initial velocity and increased the Michaelis constant of T4 DNA ligase. Mismatches at 5'- and 3'-ends of the nick have also shown different influences on the ligation. Results here showed that the sugar pucker conformation at 3'-end impairs the ligation efficiency more profoundly than that at 5'-end. Different concentrations of Mg(2+), Ca(2+), K(+), Na(+), and ATP were also demonstrated to affect the T4 DNA ligase activity. These results enriched our knowledge about the effects of 2'-OMeN substitutions on the T4 DNA ligase.

  6. Realizing Serine/Threonine Ligation: Scope and Limitations and Mechanistic Implication Thereof

    Directory of Open Access Journals (Sweden)

    Clarence T. T. Wong


    Full Text Available Serine/Threonine ligation (STL has emerged as an alternative tool for protein chemical synthesis, bioconjugations as well as macrocyclization of peptides of various sizes. Owning to the high abundance of Ser/Thr residues in natural peptides and proteins, STL is expected to find a wide range of applications in chemical biology research. Herein, we have fully investigated the compatibility of the serine/threonine ligation strategy for X-Ser/Thr ligation sites, where X is any of the 20 naturally occurring amino acids. Our studies have shown that 17 amino acids are suitable for ligation, while Asp, Glu, and Lys are not compatible. Among the working 17 C-terminal amino acids, the retarded reaction resulted from the bulky β-branched amino acid (Thr, Val and Ile is not seen under the current ligation condition. We have also investigated the chemoselectivity involving the amino group of the internal lysine which may compete with the N-terminal Ser/Thr for reaction with the C-terminal salicylaldehyde (SAL ester aldehyde group. The result suggested that the free internal amino group does not adversely slow down the ligation rate.

  7. High power Ka band TWT amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Golkowski, C.; Ivers, J.D.; Nation, J.A.; Wang, P.; Schachter, L.


    Two high power 35 GHz TWT amplifiers driven by a relativistic pencil, 850 kV, 200A electron beam have been assembled and tested. The first had a dielectric slow wave structure and was primarily used to develop diagnostics, and to gain experience in working with high power systems in Ka band. The source of the input power for the amplifier was a magnetron producing a 30 kW, 200ns long pulse of which 10 kW as delivered to the experiment. The 30 cm long dielectric (Teflon) amplifier produced output power levels of about 1 MW with a gain of about 23 dB. These results are consistent with expectations from PIC code simulations for this arrangement. The second amplifier, which is a single stage disk loaded slow wave structure, has been designed. It consists of one hundred uniform cells with two sets of ten tapered calls at the ends to lower the reflection coefficient. The phase advance per cell is {pi}/2. The amplifier passband extends from 28 to 40 GHz. It is designed to increase the output power to about 20 MW. The amplifier is in construction and will be tested in the near future. Details of the design of both systems will be provided and initial results from the new amplifier presented.

  8. Integrin Ligation Results in Nephrin Tyrosine Phosphorylation In Vitro.

    Directory of Open Access Journals (Sweden)

    Rakesh Verma

    Full Text Available Nephrin is expressed at the basolateral aspect of podocytes and is an important signaling protein at the glomerular slit diaphragm. In vitro studies have demonstrated that Nephrin phosphorylation-dependent signaling is able to assemble a protein complex that is able to polymerize actin. However, proximal signaling events that result in nephrin tyrosine phosphorylation are not well understood. Nephrin deletion in mice and human nephrin mutations result in developmental failure of the podocyte intercellular junction resutling in proteinuria. This has been presumed to be due to a failure to respond to an external polarized cue in the absence of nephrin or a failure to transduce an outside-in signal in patients with nephrin mutations. The nephrin extracellular domain binds to itself or neph1 across the foot process intercellular junction. Nephrin is tyrosine phosphorylation-silent in healthy glomeruli when presumably the nephrin extracellular domain is in an engaged state. These observations raise the possibility of an alternate proximal signaling mechanism that might be responsible for nephrin tyrosine phosphorylation. Here we present data showing that integrin engagement at the basal aspect of cultured podocytes results in nephrin tyrosine phosphorylation. This is abrogated by incubating podocytes with an antibody that prevents integrin β1 ligation and activation in response to binding to extracellular matrix. Furthermore, nephrin tyrosine phosphorylation was observed in podocytes expressing a membrane-targeted nephrin construct that lacks the extracellular domain. We propose, integrin-activation based signaling might be responsible for nephrin phosphorylation rather than engagment of the nephrin extracellular domain by a ligand.

  9. Endoscopic band ligation for bleeding lesions in the small bowel

    Institute of Scientific and Technical Information of China (English)

    Takashi; Ikeya; Naoki; Ishii; Yuto; Shimamura; Kaoru; Nakano; Mai; Ego; Kenji; Nakamura; Koichi; Takagi; Katsuyuki; Fukuda; Yoshiyuki; Fujita


    AIM: To investigate the safety and efficacy of endo-scopic band ligation(EBL) for bleeding lesions in the small bowel.METHODS: This is a retrospective study evaluating EBL in six consecutive patients(three males, three fe-males, 46-86 years of age) treated between May 2009 and February 2014: duodenal vascular ectasia; 1, je-junal bleeding diverticulum; 1, ileal Dieulafoy’s lesion; 1 and ileal bleeding diverticula; 3. The success of the initial hemostasis was evaluated, and patients were observed for early rebleeding(within 30 d after EBL), and complications such as perforation and abscess for-mation. Follow-up endoscopies were performed in four patients.RESULTS: Initial hemostasis was successfully achieved with EBL in all six patients. Eversion was not sufficient in four diverticular lesions. Early rebleeding occurred three days after EBL in one ileal diverticulum, and arepeat endoscopy revealed dislodgement of the O-band and ulcer formation at the banded site. This rebleeding was managed conservatively. Late rebleeding occurred in this case(13 and 21 mo after initial EBL), and re-EBL was performed. Follow-up endoscopies revealed scar formation and the disappearance of vascular lesions at the banded site in the case with a duodenal bleeding lesion, and unresolved ileal diverticula in three cases. Surgery or transarterial embolization was not required without any complications during the median follow-up period of 45(range, 2-83) mo.CONCLUSION: EBL is a safe and effective endoscopic treatment for hemostasis of bleeding lesions in the small bowel.

  10. An Envelope Hammerstein Model for Power Amplifiers

    Institute of Scientific and Technical Information of China (English)

    Hua-Dong Wang; Song-Bai He; Jing-Fu Bao; Zheng-De Wu


    In this paper, an envelope Hammerstein(EH) model is introduced to describe dynamic inputoutput characteristics of RF power amplifiers. In the modeling approach, we use a new truncation method and an established nonlinear time series method to determine model structure. Then, we discuss the process of model parameter extraction in detailed. Finally, a 2 W WCDMA power amplifier is measured to verify the performance of EH model, and good agreement between model output and measurement result shows our model can accurately predict output characteristic of the power amplifier.

  11. Quantum electronics maser amplifiers and oscillators

    CERN Document Server

    Fain, V M; Sanders, J H


    Quantum Electronics, Volume 2: Maser Amplifiers and Oscillators deals with the experimental and theoretical aspects of maser amplifiers and oscillators which are based on the principles of quantum electronics. It shows how the concepts and equations used in quantum electronics follow from the basic principles of theoretical physics.Comprised of three chapters, this volume begins with a discussion on the elements of the theory of quantum oscillators and amplifiers working in the microwave region, along with the practical achievements in this field. Attention is paid to two-level paramagnetic ma

  12. Effect of Soliton Propagation in Fiber Amplifiers

    Institute of Scientific and Technical Information of China (English)


    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.

  13. High Efficiency Microwave Power Amplifier (HEMPA) Design (United States)

    Sims, W. Herbert


    This paper will focus on developing an exotic switching technique that enhances the DC-to-RF conversion efficiency of microwave power amplifiers. For years, switching techniques implemented in the 10 kHz to 30 MHz region have resulted in DC-to-RF conversion efficiencies of 90-95-percent. Currently amplifier conversion efficiency, in the 2-3 GHz region approaches, 10-20-percent. Using a combination of analytical modeling and hardware testing, a High Efficiency Microwave Power Amplifier was built that demonstrated conversion efficiencies four to five times higher than current state of the art.

  14. Fundamentals of RF and microwave transistor amplifiers

    CERN Document Server

    Bahl, Inder J


    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

  15. Experimental design of laminar proportional amplifiers (United States)

    Hellbaum, R. F.


    An experimental program was initiated at Langley Research Center to study the effects of various parameters on the design of laminar proportional beam deflection amplifiers. Matching and staging of amplifiers to obtain high-pressure gain was also studied. Variable parameters were aspect ratio, setback, control length, receiver distance, receiver width, width of center vent, and bias pressure levels. Usable pressure gains from 4 to 19 per stage can now be achieved, and five amplifiers were staged together to yield pressure gains up to 2,000,000.

  16. Phase noise in RF and microwave amplifiers. (United States)

    Boudot, Rodolphe; Rubiola, Enrico


    Understanding amplifier phase noise is a critical issue in many fields of engineering and physics, such as oscillators, frequency synthesis, telecommunication, radar, and spectroscopy; in the emerging domain of microwave photonics; and in exotic fields, such as radio astronomy, particle accelerators, etc. Focusing on the two main types of base noise in amplifiers, white and flicker, the power spectral density of the random phase φ(t) is Sφ(f) = b(0) + b(-1)/f. White phase noise results from adding white noise to the RF spectrum in the carrier region. For a given RF noise level, b(0) is proportional to the reciprocal of the carrier power P(0). By contrast, flicker results from a near-dc 1/f noise-present in all electronic devices-which modulates the carrier through some parametric effect in the semiconductor. Thus, b(-1) is a parameter of the amplifier, constant in a wide range of P(0). The consequences are the following: Connecting m equal amplifiers in parallel, b(-1) is 1/m times that of one device. Cascading m equal amplifiers, b(-1) is m times that of one amplifier. Recirculating the signal in an amplifier so that the gain increases by a power of m (a factor of m in decibels) as a result of positive feedback (regeneration), we find that b(-1) is m(2) times that of the amplifier alone. The feedforward amplifier exhibits extremely low b(-1) because the carrier is ideally nulled at the input of its internal error amplifier. Starting with an extensive review of the literature, this article introduces a system-oriented model which describes the phase flickering. Several amplifier architectures (cascaded, parallel, etc.) are analyzed systematically, deriving the phase noise from the general model. There follow numerous measurements of amplifiers using different technologies, including some old samples, and in a wide frequency range (HF to microwaves), which validate the theory. In turn, theory and results provide design guidelines and give suggestions for CAD and

  17. Achieving and maintaining cleanliness in NIF amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Burnham, A. K.; Horvath, J. A.; Letts, S. A.; Menapace, J. A.; Stowers, I. F.


    Cleanliness measurements made on AMPLAB prototype National Ignition Facility (NIF) laser amplifiers during assembly, cassette transfer, and amplifier operation are summarized. These measurements include particle counts from surface cleanliness assessments using filter swipe techniques and from airborne particle monitoring. Results are compared with similar measurements made on the Beamlet and Nova lasers and in flashlamp test fixtures. Observations of Class 100,000 aerosols after flashlamp firings are discussed. Comparisons are made between typical damage densities on laser amplifier optics from Novette, NOVA, Beamlet, and AMPLAB.

  18. A comparative study on time efficiency management of self ligating brackets with conventional ligating brackets on orthodontic subjects in North Karnataka

    Directory of Open Access Journals (Sweden)

    Smita B. Patil


    Full Text Available Background: Self-Ligating brackets were originally designed with the intention to reduce the time needed to change wires compared with the use of wire ligatures. However, the advent of elastomeric ligatures meant that this perceived advantage was diminished. Objective: To compare aligning efficiency, rate of retraction and torque expression of Self Ligating bracket (SLB system with Conventional Pre adjusted Edgewise bracket (CLB system. Materials and Methods: Twelve patients were selected and divided into two groups treated with self ligating brackets (SLB, n=6 and conventional ligating brackets (CLB, n=6. The brackets used were 0.22 slot McLaughlin Bennet Trevesi (MBT prescription. Aligning was evaluated with 0.14 Niti followed by 19X25 Heat Activated Ni Ti and then 19X25 stainless steel wires for retraction within 4 months. The rate of retraction was evaluated per month and torque loss after space closure was also estimated. Results: Alignment Efficiency shows significant changes with SLB compared to CLB and also save more than 30% of chair side time during wire adjustments while rate of en masse retraction in SLB shows statistically non significance as compared to CLB system. In case of upper incisor changes when compared between two groups showed less torque loss in SLB than CLB although which was statistically no significant but % difference show SLB have better improvement result than CLB.

  19. Self-pulsation in Raman fiber amplifiers


    Pedersen, Martin Erland Vestergaard; Ott, Johan Raunkjær; Rottwitt, Karsten


    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.

  20. Laser Cooled High-Power Fiber Amplifier

    CERN Document Server

    Nemova, Galina


    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 of a small deviation in the value of the amplified signal on the temperature of the fiber with the fixed distribution of the Tm3+ions in the fiber cladding is investigated.

  1. High Energy Single Frequency Resonant Amplifier Project (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...

  2. Treatment of glioblastoma multiforme cells with temozolomide-BioShuttle ligated by the inverse Diels-Alder ligation chemistry

    Directory of Open Access Journals (Sweden)

    Klaus Braun


    Full Text Available Klaus Braun1, Manfred Wiessler1, Volker Ehemann2, Ruediger Pipkorn3, Herbert Spring4, Juergen Debus5, Bernd Didinger5, Mario Koch3, Gabriele Muller6, Waldemar Waldeck61German Cancer Research Center, Dept of Imaging and Radiooncology, Heidelberg, Germany; 2University of Heidelberg, Institute of Pathology, Heidelberg, Germany; 3German Cancer Research Center, Central Peptide Synthesis Unit, Heidelberg, Germany; 4German Cancer Research Center, Dept of Structural Analysis of Gene Structure and Function, Heidelberg, Germany; 5University of Heidelberg, Dept of Radiation Oncology, Heidelberg, Germany; 6German Cancer Research Center,Division of Biophysics of Macromolecules, Heidelberg, GermanyAbstract: Recurrent glioblastoma multiforme (GBM, insensitive against most therapeutic interventions, has low response and survival rates. Temozolomide (TMZ was approved for second-line therapy of recurrent anaplastic astrocytoma. However, TMZ therapy in GBM patients reveals properties such as reduced tolerability and inauspicious hemogram. The solution addressed here concerning GBM therapy consolidates and uses the potential of organic and peptide chemistry with molecular medicine. We enhanced the pharmacologic potency with simultaneous reduction of unwanted adverse reactions of the highly efficient chemotherapeutic TMZ. The TMZ connection to transporter molecules (TMZ-BioShuttle was investigated, resulting in a much higher pharmacological effect in glioma cell lines and also with reduced dose rate. From this result we can conclude that a suitable chemistry could realize the ligation of pharmacologically active, but sensitive and highly unstable pharmaceutical ingredients without functional deprivation. The TMZ-BioShuttle dramatically enhanced the potential of TMZ for the treatment of brain tumors and is an attractive drug for combination chemotherapy.Keywords: drug delivery, carrier molecules, facilitated transport, glioblastoma multiforme, temozolomide

  3. Efficient Power Amplifier for Motor Control (United States)

    Brown, R. J.


    Pulse-width-modulated amplifier supplies high current as efficiently as low current needed for starting and running motor. Key to efficiency of motor-control amplifier is V-channel metal-oxide/semiconductor transistor Q1. Device has low saturation resistance. However, has large gate input capacitance and small margin between its turn-on voltage and maximum allowable gate-to-source voltage. Circuits for output stages overcome limitations of VMOS device.

  4. Quantum cloning with an optical fiber amplifier

    CERN Document Server

    Fasel, S; Ribordy, G; Scarani, V; Zbinden, H; Fasel, Sylvain; Gisin, Nicolas; Ribordy, Gregoire; Scarani, Valerio; Zbinden, Hugo


    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 $1\\to 2$ we find a fidelity of 0.82, the optimal value being ${5/6}=0.83$.

  5. CMOS current amplifiers : speed versus nonlinearity



    This work deals with analogue integrated circuit design using various types of current-mode amplifiers. These circuits are analysed and realised using modern CMOS integration technologies. The dynamic nonlinearities of these circuits are discussed in detail as in the literature only linear nonidealities and static nonlinearities are conventionally considered. For the most important open-loop current-mode amplifier, the second-generation current-conveyor (CCII), a macromodel is derived tha...

  6. MMIC Amplifiers for 90 to 130 GHz (United States)

    Samoska, Lorene; Pukala, David; Peralta, Alejandro; Bryerton, Eric; Morgan, Matt; Boyd, T.; Hu, Ming; Schmitz, Adele


    This brief describes two monolithic microwave integrated-circuit (MMIC) amplifier chips optimized to function in the frequency range of 90 to 130 GHz, covering nearly all of F-band (90 - 140 GHz). These amplifiers were designed specifically for local-oscillator units in astronomical radio telescopes such as the Atacama Large Millimeter Array (ALMA). They could also be readily adapted for use in electronic test equipment, automotive radar systems, and communications systems that operate between 90 and 130 GHz.

  7. Multiple ligation of the proximal greater saphenous vein in the CHIVA treatment of primary varicose veins

    Directory of Open Access Journals (Sweden)

    Roberto Delfrate


    Full Text Available Saphenous femoral disconnection is the key point of most surgical techniques in the treatment of primary varicose vein surgery. The aim of this study is to compare and analyze different techniques for conservative saphenousfemoral ligation or disconnection. These techniques can be to perform mini invasive open surgery and are suitable for implementation of the conservative hemodynamic correction of venous insufficiency (CHIVA method. The aim was to present the follow-up by retrospective analysis of three different ligation-disconnection techniques of the proximal great saphenous vein (GSV according to the CHIVA method at the GSV end, i.e. between the very end of the GSV and the first arch tributary, according to the CHIVA method. The first thecnique consisted of a surgical division (crossotomy. The other two consisted of triple superposed ligation with No. 2 non-absorbable braided coated suture without division labeled TSFL (triple saphenous flush ligation and No. 0 polypropylenene ligation TPL (triple polypropylene ligation. The difference between TSFL and TPL was in the thickness and type of material of the thread, though both were non-absorbable. The follow up of 56 TPL procedures, 61 crossotomy procedures, and 82 TSFL procedures was analysed. The follow-up consisted of checking the sapheno-femoral junction occlusion with Duplex color ultra sound. The incidence rates of neovascularization (new vessels in the ligation or surgical disconnection site with saphenous-femoral reflux during the Valsalva maneuver were: 4.9% for the crossotomy group, 6.1% for the TSFL group and 37.5% for the TPL group. The data analysed show satisfactory results with both crossotomy and TSFL. Crossotomy has proven to be an effective technique for performing saphenous-femoral disconnection, but TSFL could also be a reliable, safe and low-cost varicose mini-invasive surgery in outpatients. TPL appeared to be less reliable.

  8. Effects of pulmonary veins ligation style for the patients' stress and cardiac on lung cancer

    Directory of Open Access Journals (Sweden)

    Yang SHENTU


    Full Text Available Background and objective It is needed to explore the effects of operation on stress statue, myocardial damage and arrhythmia to lung cancer. This study would compare the effects of two ligation styles of pulmonary vein on lung cancer patients' stress and cardiac postoperative. Methods 54 cases were divided into two groups randomly:the pulmonary vein trunk-ligation group (trunk group, 27 cases and the pulmonary vein branch-ligation group (branch group, 27 cases. The blood concentrations of hydrocortisone (HC, blood glucose (BG and cardial troponin-I (cTnI were determined at different time point. The surgical data, the quantum of pain and ECG also recorded. Results ① There were no significance difference of the operation time, blood loss during operation and drainage volume in first day after operation between two groups. ② There're no differences of the quantum of pain between two groups. ③ The HC of the two groups' ascend obviously on the end of operation and descend during postoperative. ④ The BG of the two groups' rise on the 1st day obviously, maintain high level on the 2nd day, descend on the 3rd day but still higher than that of preoperation.⑤ The BG and HC show a direct positive correlation postoperative. ⑥ The cTnIs of the trunk group ascend immediatelyafter operation, but there's no statistically significance between two groups. ⑦ The arrhythmia incidence is higher in the trunk group, but the arrhythmia incidences classified by the date after operation of the two groups' show no distinction. Conclusion ① The effects of two pulmonary vein ligation styles on postoperative stress show no significance differences.② The style of pulmonary vein trunk-ligation has a more obvious tendency to do harm to heart than that of branch-ligation. ③ The style of pulmonary vein branch-ligation may reduce the arrhythmia incidence after operation.

  9. Optimum level of inferior mesenteric artery ligation for the left-sided colorectal cancer (United States)

    Guraya, Salman Y.


    Objectives: To compares the effectiveness and impact of high inferior mesenteric artery (IMA) versus low IMA ligation on 5-year survival, lymph node yield rates, and peri-operative morbidity and mortality. Methods: The databases of Educational Resources Information Centre (ERIC), the Web of Science, EBSCO and MEDLINE were searched using MeSH terms ‘colorectal cancer’, ‘inferior mesenteric artery’, ‘high ligation’, ‘low ligation’, ‘mesenteric lymph nodes’, ‘prognosis’, and ‘survival’. Only clinical studies were selected and review articles and meta-analysis were excluded. In cases of duplicate cohorts, only the latest article was included. Irrelevant articles and the articles on both right and left sided CRC were excluded. The finally selected studies were analysed for the defined end-point outcomes. Results: The published data has shown that high IMA ligation improves the yield of harvested lymph node that allows accurate tumor staging and a more reliable estimation of prognosis. High ligation was not found to be positively correlated with increased anastomotic leakage or impaired genito-urinary function. However, high ligation demands advanced surgical expertise and longer operating time. There was no significant difference in 5-year survival rates for both techniques. Some studies have reported fatal complications of high ligation such as proximal bowel necrosis. Conclusion: Although there is no consensus, this research signals the routine use of high ligation for left-sided CRC. However, the published fatal complications following high ligation and no significant difference in 5-year survival rates demand more studies to establishing a unified protocol. PMID:27381531

  10. Some Notes on Wideband Feedback Amplifiers (United States)

    Fitch, V.


    The extension of the passband of wideband amplifiers is a highly important problem to the designer of electronic circuits. Throughout the electronics industry and in many research programs in physics and allied fields where extensive use is made of video amplifiers, the foremost requirement is a passband of maximum width. This is necessary if it is desired to achieve a more faithful reproduction of transient wave forms, a better time resolution in physical measurements, or perhaps just a wider band gain-frequency response to sine wave signals. The art of electronics is continually faced with this omnipresent amplifier problem. In particular, the instrumentation techniques of nuclear physics require amplifiers with short rise times, a high degree of gain stability, and a linear response to high signal levels. While the distributed amplifier may solve the problems of those seeking only a wide passband, the requirements of stability and linearity necessitate using feedback circuits. This paper considers feedback amplifiers from the standpoint of high-frequency performance. The circuit conditions for optimum steady-state (sinusoidal) and transient response are derived and practical circuits (both interstage and output) are presented which fulfill these conditions. In general, the results obtained may be applied to the low-frequency end.

  11. Low Noise Optically Pre-amplified Lightwave Receivers and Other Applications of Fiber Optic Parametric Amplifiers (United States)


    noise performance, optical gain bandwidth, and power efficiency. An interesting alternative to the mature Erbium-doped fiber amplifier ( EDFA ) is the...fibers (HNLF) and high power booster EDFAs . The FOPA can provide a very wide gain bandwidth [2], very high gain (70 dB was demonstrated in [3]), and...amplified spontaneous emission (ASE) noise in EDFAs is also generated. It is sometimes referred to as amplified quantum noise. Maximum gain (at the gain

  12. Selective desulfurization of cysteine in the presence of Cys(Acm) in polypeptides obtained by native chemical ligation. (United States)

    Pentelute, Brad L; Kent, Stephen B H


    Increased versatility for the synthesis of proteins and peptides by native chemical ligation requires the ability to ligate at positions other than Cys. Here, we report that Raney nickel can be used under standard conditions for the selective desulfurization of Cys in the presence of Cys(Acm). This simple and practical tactic enables the more common Xaa-Ala junctions to be used as ligation sites for the chemical synthesis of Cys-containing peptides and proteins. [reaction: see text].

  13. In Situ Proximity Ligation Assay (PLA) Analysis of Protein Complexes Formed Between Golgi-Resident, Glycosylation-Related Transporters and Transferases in Adherent Mammalian Cell Cultures. (United States)

    Maszczak-Seneczko, Dorota; Sosicka, Paulina; Olczak, Teresa; Olczak, Mariusz


    In situ proximity ligation assay (PLA) is a novel, revolutionary technique that can be employed to visualize protein complexes in fixed cells and tissues. This approach enables demonstration of close (i.e., up to 40 nm) proximity between any two proteins of interest that can be detected using a pair of specific antibodies that have been raised in distinct species. Primary antibodies bound to the target proteins are subsequently recognized by two PLA probes, i.e., secondary antibodies conjugated with oligonucleotides that anneal when brought into close proximity in the presence of two connector oligonucleotides and a DNA ligase forming a circular DNA molecule. In the next step, the resulting circular DNA is amplified by a rolling circle polymerase. Finally, fluorescent oligonucleotide probes hybridize to complementary fragments of the amplified DNA molecule, forming a typical, spot-like pattern of PLA signal that reflects subcellular localization of protein complexes. Here we describe the use of in situ PLA in adherent cultures of mammalian cells in order to visualize interactions between Golgi-resident, functionally related glycosyltransferases and nucleotide sugar transporters relevant to N-glycan biosynthesis.

  14. Effects of double ligation of Stensen's duct on the rabbit parotid gland. (United States)

    Maria, O M; Maria, S M; Redman, R S; Maria, A M; Saad El-Din, T A; Soussa, E F; Tran, S D


    Salivary gland duct ligation is an alternative to gland excision for treating sialorrhea or reducing salivary gland size prior to tumor excision. Duct ligation also is used as an approach to study salivary gland aging, regeneration, radiotherapy, sialolithiasis and sialadenitis. Reports conflict about the contribution of each salivary cell population to gland size reduction after ductal ligation. Certain cell populations, especially acini, reportedly undergo atrophy, apoptosis and proliferation during reduction of gland size. Acini also have been reported to de-differentiate into ducts. These contradictory results have been attributed to different animal or salivary gland models, or to methods of ligation. We report here a bilateral double ligature technique for rabbit parotid glands with histologic observations at 1, 7, 14, 30, 60 days after ligation. A large battery of special stains and immunohistochemical procedures was employed to define the cell populations. Four stages with overlapping features were observed that led to progressive shutdown of gland activities: 1) marked atrophy of the acinar cells occurred by 14 days, 2) response to and removal of the secretory material trapped in the acinar and ductal lumens mainly between 30 and 60 days, 3) reduction in the number of parenchymal (mostly acinar) cells by apoptosis that occurred mainly between 14-30 days, and 4) maintenance of steady-state at 60 days with a low rate of fluid, protein, and glycoprotein secretion, which greatly decreased the number of leukocytes engaged in the removal of the luminal contents. The main post- ligation characteristics were dilation of ductal and acinar lumens, massive transient infiltration of mostly heterophils (rabbit polymorphonuclear leukocytes), acinar atrophy, and apoptosis of both acinar and ductal cells. Proliferation was uncommon except in the larger ducts. By 30 days, the distribution of myoepithelial cells had spread from exclusively investing the intercalated ducts

  15. Template-directed ligation of tethered mononucleotides by t4 DNA ligase for kinase ribozyme selection.

    Directory of Open Access Journals (Sweden)

    David G Nickens

    Full Text Available BACKGROUND: In vitro selection of kinase ribozymes for small molecule metabolites, such as free nucleosides, will require partition systems that discriminate active from inactive RNA species. While nucleic acid catalysis of phosphoryl transfer is well established for phosphorylation of 5' or 2' OH of oligonucleotide substrates, phosphorylation of diffusible small molecules has not been demonstrated. METHODOLOGY/PRINCIPAL FINDINGS: This study demonstrates the ability of T4 DNA ligase to capture RNA strands in which a tethered monodeoxynucleoside has acquired a 5' phosphate. The ligation reaction therefore mimics the partition step of a selection for nucleoside kinase (deoxyribozymes. Ligation with tethered substrates was considerably slower than with nicked, fully duplex DNA, even though the deoxynucleotides at the ligation junction were Watson-Crick base paired in the tethered substrate. Ligation increased markedly when the bridging template strand contained unpaired spacer nucleotides across from the flexible tether, according to the trends: A(2>A(1>A(3>A(4>A(0>A(6>A(8>A(10 and T(2>T(3>T(4>T(6 approximately T(1>T(8>T(10. Bridging T's generally gave higher yield of ligated product than bridging A's. ATP concentrations above 33 microM accumulated adenylated intermediate and decreased yields of the gap-sealed product, likely due to re-adenylation of dissociated enzyme. Under optimized conditions, T4 DNA ligase efficiently (>90% joined a correctly paired, or TratioG wobble-paired, substrate on the 3' side of the ligation junction while discriminating approximately 100-fold against most mispaired substrates. Tethered dC and dG gave the highest ligation rates and yields, followed by tethered deoxyinosine (dI and dT, with the slowest reactions for tethered dA. The same kinetic trends were observed in ligase-mediated capture in complex reaction mixtures with multiple substrates. The "universal" analog 5-nitroindole (dNI did not support ligation when

  16. Nucleosome linker proteins HMGB1 and histone H1 differentially enhance DNA ligation reactions. (United States)

    Yamanaka, Shiho; Katayama, Eisaku; Yoshioka, Ken-ichi; Nagaki, Sumiko; Yoshida, Michiteru; Teraoka, Hirobumi


    We previously reported that HMGB1, which originally binds to chromatin in a manner competitive with linker histone H1 to modulate chromatin structure, enhances both intra-molecular and inter-molecular ligations. In this paper, we found that histone H1 differentially enhances ligation reaction of DNA double-strand breaks (DSB). Histone H1 stimulated exclusively inter-molecular ligation reaction of DSB with DNA ligase IIIbeta and IV, whereas HMGB1 enhanced mainly intra-molecular ligation reaction. Electron microscopy of direct DNA-protein interaction without chemical cross-linking visualized that HMGB1 bends and loops linear DNA to form compact DNA structure and that histone H1 is capable of assembling DNA in tandem arrangement with occasional branches. These results suggest that differences in the enhancement of DNA ligation reaction are due to those in alteration of DNA configuration induced by these two linker proteins. HMGB1 and histone H1 may function in non-homologous end-joining of DSB repair and V(D)J recombination in different manners.

  17. Bias in ligation-based small RNA sequencing library construction is determined by adaptor and RNA structure.

    Directory of Open Access Journals (Sweden)

    Ryan T Fuchs

    Full Text Available High-throughput sequencing (HTS has become a powerful tool for the detection of and sequence characterization of microRNAs (miRNA and other small RNAs (sRNA. Unfortunately, the use of HTS data to determine the relative quantity of different miRNAs in a sample has been shown to be inconsistent with quantitative PCR and Northern Blot results. Several recent studies have concluded that the major contributor to this inconsistency is bias introduced during the construction of sRNA libraries for HTS and that the bias is primarily derived from the adaptor ligation steps, specifically where single stranded adaptors are sequentially ligated to the 3' and 5'-end of sRNAs using T4 RNA ligases. In this study we investigated the effects of ligation bias by using a pool of randomized ligation substrates, defined mixtures of miRNA sequences and several combinations of adaptors in HTS library construction. We show that like the 3' adaptor ligation step, the 5' adaptor ligation is also biased, not because of primary sequence, but instead due to secondary structures of the two ligation substrates. We find that multiple secondary structural factors influence final representation in HTS results. Our results provide insight about the nature of ligation bias and allowed us to design adaptors that reduce ligation bias and produce HTS results that more accurately reflect the actual concentrations of miRNAs in the defined starting material.

  18. Transpermeance Amplifier Applied to Magnetic Bearings

    Directory of Open Access Journals (Sweden)

    Jossana Ferreira


    Full Text Available The most conventional approach of controlling magnetic forces in active magnetic bearings (AMBs is through current feedback amplifiers: transconductance. This enables the operation of the AMB to be understood in terms of a relatively simple current-based model as has been widely reported on in the literature. The alternative notion of using transpermeance amplifiers, which approximate the feedback of gap flux rather than current, has been in commercial use in some form for at least thirty years, however is only recently seeing more widespread acceptance as a commercial standard. This study explores how such alternative amplifiers should be modeled and then examines the differences in behavior between AMBs equipped with transconductance and transpermeance amplifiers. The focus of this study is on two aspects. The first is the influence of rotor displacement on AMB force, commonly modeled as a constant negative equivalent mechanical stiffness, and it is shown that either scheme actually leads to a finite bandwidth effect, but that this bandwidth is much lower when transpermeance is employed. The second aspect is the influence of eddy currents. Using a very simple model of eddy currents (a secondary short-circuited coil, it is demonstrated that transpermeance amplifiers can recover significant actuator bandwidth compared with transconductance, but at the cost of needing increased peak current headroom.

  19. High power, high beam quality regenerative amplifier (United States)

    Hackel, L.A.; Dane, C.B.


    A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

  20. Determination of the antiulcer properties of sodium cromoglycate in pylorus-ligated albino rats

    Directory of Open Access Journals (Sweden)

    Srivastava Vivek


    Full Text Available Objectives : To study the ulcer protective property of sodium cromoglycate in pylorus-ligated rats and the biochemical role in ulcer protection by various biochemical tests. Materials and Methods : The ulcer protective effect of sodium cromoglycate was studied using a Pyloric Ligation Model using Wistar albino rats. The antiulcer effect of sodium cromoglycate 40 mg/kg b.w., i.p., was compared with the reference drug ranitidine 27 mg/kg b.w., i.p. The ulcer index was calculated and other biochemical parameters like free acidity, total acidity, pH, mucin, pepsin and volume of gastric juice were determined. Results : Pylorus ligation showed a significant (P < 0.01 reduction in gastric volume, free acidity, total acidity and ulcer index as compared to the control. Conclusion : Sodium cromoglycate has activity equipotent to ranitidine.

  1. Ligation versus bipolar diathermy for hemostasis in tonsillectomy: a comparative study. (United States)

    Sharma, Karan; Kumar, Devinder


    Tonsillectomy despite being less performed nowadays still is a very common surgery performed by ENT surgeons. The use of various modalities like bipolar diathermy, laser, cryosurgery, radiofrequency and ionic coblation for hemostasis in tonsillectomy remains controversial so far. A thorough scan of literature comparing the ligation with diathermy has been presented. In this prospective study, we analysed 50 patients undergoing tonsillectomy by dissection method. Right sided tonsillectomies act as study group (bipolar diathermy used) and left sided tonsillectomies as the control group (ligation for hemostasis used). The aim of our study is to compare the amount of blood loss, number of ligatures applied, average time taken and incidence of postoperative haemorrhage following the use of ligation and bipolar diathermy. The study found that diathermy hemostatic technique is associated with a quicker procedure, less intraoperative blood loss, comparable postoperative pain.

  2. Influence of polyethylene glycol on the ligation reaction with calf thymus DNA ligases I and II. (United States)

    Teraoka, H; Tsukada, K


    High concentrations of the nonspecific macromolecule polyethylene glycol 6000 (PEG 6000) enabled DNA ligases I and II from calf thymus to catalyze intermolecular blunt-end ligation of duplex DNA. Intermolecular cohesive-end ligation with these enzymes was markedly stimulated in the presence of 10-16% (w/v) PEG 6000. The effect of PEG 6000 (4-16%) on the sealing of single-stranded breaks in duplex DNA with DNA ligases I and II was not appreciably stimulatory but rather inhibitory. PEG 6000 (15%) enhanced more twofold the rate of DNA ligase II-AMP complex formation, but moderately suppressed the rate of formation of DNA ligase 1-AMP complex. Polyamines and KCl inhibited blunt-end and cohesive-end ligations with DNA ligases I and II in the presence of PEG 6000.


    Directory of Open Access Journals (Sweden)

    Sanjay Jain*, Rakesh Barik, Nidhi Yadav and Shivpal Singh


    Full Text Available Tribulus terrestris L. (TT; Zygophyllaceae is employed in the folk medicine against sexual impotence, oedemas, abdominal distention and cardiovascular diseases. Gastroprotective (i.e. antiulcer and anti-secretory potential of methanolic extract of TT fruits was evaluated in pylorus-ligated rat model of Wistar rat. The methanolic extract of TT was tested orally at the doses of 150, 300 & 600 mg/kg, on gastric ulcerations experimentally induced by pylorus ligation. Preliminary phytochemical screening of the methanol extract of TT showed the presence of alkaloids, carbohydrates, cardiac glycosides, flavonoids, saponins, tannins and proteins. The methanolic extract at the doses of 300 & 600 mg/kg produced more significant inhibition when gastric ulcerations were induced by pylorus ligation respectively. The methanol extract of the fruits of Tribulus terrestris L. possess gastroprotective i.e. antiulcer and anti-secretory effect.

  4. The OPTHER Project: Progress toward the THz Amplifier

    DEFF Research Database (Denmark)

    Paoloni, C; Brunetti, F; Di Carlo, A


    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...

  5. Frictional resistance of self-ligating versus conventional brackets in different bracket-archwire-angle combinations

    Directory of Open Access Journals (Sweden)

    Maria Regina Guerra MONTEIRO


    Full Text Available Objective: To compare the influence of archwire material (NiTi, beta-Ti and stainless steel and brackets design (self-ligating and conventional on the frictional force resistance. Material and Methods: Two types of brackets (self-ligating brackets - Smartclip, 3M/Unitek - and conventional brackets - Gemini, 3M/Unitek with three (0, 5, and 10 degrees slot angulation attached with elastomeric ligatures (TP Orthodontics were tested. All brackets were tested with archwire 0.019"x0.025" nickel-titanium, beta-titanium, and stainless steel (Unitek/3M. The mechanical testing was performed with a universal testing machine eMIC DL 10000 (eMIC Co, Brazil. The wires were pulled from the bracket slots at a cross-head speed of 3 mm/min until 2 mm displacement. Results: Self-ligating brackets produced significantly lower friction values compared with those of conventional brackets. Frictional force resistance values were directly proportional to the increase in the bracket/ wire angulation. With regard to conventional brackets, stainless steel wires had the lowest friction force values, followed by nickel-titanium and beta-titanium ones. With regard to self-ligating brackets, the nickel-titanium wires had the lowest friction values, significantly lower than those of other materials. Conclusion: even at different angulations, the self-ligating brackets showed significantly lower friction force values than the conventional brackets. Combined with nickel-titanium wires, the self-ligating brackets exhibit much lower friction, possibly due to the contact between nickel-titanium clips and wires of the same material.

  6. The effect of ligation of the distal vein in snuff-box arteriovenous fistula

    Directory of Open Access Journals (Sweden)

    Beigi Ali


    Full Text Available Arterio-venous fistula (AVF in the snuff-box region is one of the current techniques used for creating a vascular access in patients undergoing dialysis. The aim of this study is to find out whether ligating the distal vein in AVF in the snuff-box will bring about any change in the efficiency and complications of the fistula. Sixty patients (30 males, 30 females suffering from chronic renal failure, who had been admitted for creating an AVF, were randomly divided into two groups after having filled out consent forms. After the AVF was made, the distal vein was ligated in the first group, but not in the second group. The patients were discharged after being given the necessary advice on how to take care of their fistula. They were examined on post-surgical days 1, 30 and 90. Early efficiency in the ligated and non-ligated groups was 100% and 96.7% respectively while late efficiency in the two groups was 90% and 83.4%, respectively (P > 0.05. The most common complication in both groups was thrombosis (11.7%. Venous hypertension and edema were observed in two patients (both from the non-ligated group and infection of the surgical site was observed in only one patient. Our study suggests that, considering the high efficiency level and low complication rate, AVF at the snuff-box region constitutes one of the best possible vascular accesses for patients undergoing hemodialysis. Ligation of the distal vein prevents the development of venous hypertension in the fistula.

  7. Isolation of novel ribozymes that ligate AMP-activated RNA substrates (United States)

    Hager, A. J.; Szostak, J. W.


    BACKGROUND: The protein enzymes RNA ligase and DNA ligase catalyze the ligation of nucleic acids via an adenosine-5'-5'-pyrophosphate 'capped' RNA or DNA intermediate. The activation of nucleic acid substrates by adenosine 5'-monophosphate (AMP) may be a vestige of 'RNA world' catalysis. AMP-activated ligation seems ideally suited for catalysis by ribozymes (RNA enzymes), because an RNA motif capable of tightly and specifically binding AMP has previously been isolated. RESULTS: We used in vitro selection and directed evolution to explore the ability of ribozymes to catalyze the template-directed ligation of AMP-activated RNAs. We subjected a pool of 10(15) RNA molecules, each consisting of long random sequences flanking a mutagenized adenosine triphosphate (ATP) aptamer, to ten rounds of in vitro selection, including three rounds involving mutagenic polymerase chain reaction. Selection was for the ligation of an oligonucleotide to the 5'-capped active pool RNA species. Many different ligase ribozymes were isolated; these ribozymes had rates of reaction up to 0.4 ligations per hour, corresponding to rate accelerations of approximately 5 x10(5) over the templated, but otherwise uncatalyzed, background reaction rate. Three characterized ribozymes catalyzed the formation of 3'-5'-phosphodiester bonds and were highly specific for activation by AMP at the ligation site. CONCLUSIONS: The existence of a new class of ligase ribozymes is consistent with the hypothesis that the unusual mechanism of the biological ligases resulted from a conservation of mechanism during an evolutionary replacement of a primordial ribozyme ligase by a more modern protein enzyme. The newly isolated ligase ribozymes may also provide a starting point for the isolation of ribozymes that catalyze the polymerization of AMP-activated oligonucleotides or mononucleotides, which might have been the prebiotic analogs of nucleoside triphosphates.

  8. Chronic heart failure model with sequential ligation of the homonymous artery and its diagonal branch in the sheep. (United States)

    Kim, W G; Park, J J; Oh, S I


    We report a reliable chronic heart failure model in sheep using sequential ligation of the homonymous artery and its diagonal branch. After a left anterior thoracotomy in Corridale sheep, the homonymous artery was ligated at a point approximately 40% of the distance from the apex to the base of the heart, and after 1 hour, the diagonal vessel was ligated at a point at the same level. Hemodynamic measurements were done preligation, 30 minutes after the homonymous artery ligation, and 1 hour after diagonal branch ligation. The electrocardiograms were obtained as needed, and cardiac function was also evaluated with ultrasonography. After a predetermined interval (2 months for five animals and 3 months for two animals), the animals were reevaluated in the same way as before, and were killed for postmortem examination of their hearts. All seven animals survived the experimental procedures. Statistically significant decreases in systemic arterial blood pressure and cardiac output and increases in pulmonary artery capillary wedge pressure were observed 1 hour after sequential ligation of the homonymous artery and its diagonal branch. Untrasonographic analyses demonstrated variable degrees of anteroseptal dyskinesia and akinesia in all animals. The data from animals at 2 months after coronary artery ligation showed significant increases in central venous pressure, pulmonary artery pressure, and pulmonary artery capillary wedge pressure. Left ventricular enddiastolic dimension and left ventricular end-systolic dimension on ultrasonographic studies were also increased. Electrocardiography showed severe ST elevation immediately after the ligation and pathologic Q waves were found at 2 months after ligation. The thin walled infarcted areas with chamber enlargement were clearly seen in the hearts removed at 2 and 3 months after ligation. In conclusion, we could achieve a reliable ovine model of chronic heart failure using a simple concept of sequential ligation of the

  9. Wideband pulse amplifiers for the NECTAr chip (United States)

    Sanuy, A.; Delagnes, E.; Gascon, D.; Sieiro, X.; Bolmont, J.; Corona, P.; Feinstein, F.; Glicenstein, J.-F.; Naumann, C. L.; Nayman, P.; Ribó, M.; Tavernet, J.-P.; Toussenel, F.; Vincent, P.; Vorobiov, S.


    The NECTAr collaboration's FE option for the camera of the CTA is a 16 bits and 1-3 GS/s sampling chip based on analog memories including most of the readout functions. This works describes the input amplifiers of the NECTAr ASIC. A fully differential wideband amplifier, with voltage gain up to 20 V/V and a BW of 400 MHz. As it is impossible to design a fully differential OpAmp with an 8 GHz GBW product in a 0.35 CMOS technology, an alternative implementation based on HF linearized transconductors is explored. The output buffer is a class AB miller operational amplifier, with special non-linear current boost.

  10. Wideband pulse amplifiers for the NECTAr chip

    Energy Technology Data Exchange (ETDEWEB)

    Sanuy, A., E-mail: [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Delagnes, E. [IRFU/DSM/CEA, CE-Saclay, Bat. 141 SEN Saclay, F-91191, Gif-sur-Yvette (France); Gascon, D. [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Sieiro, X. [Departament d' Electronica, Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Bolmont, J.; Corona, P. [LPNHE, Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Barre 12-22, 1er etage, 4 place Jussieu, 75252 Paris (France); Feinstein, F. [LUPM, Universite Montpellier II and IN2P3/CNRS, CC072, bat. 13, place Eugene Bataillon, 34095 Montpellier (France); Glicenstein, J-F. [IRFU/DSM/CEA, CE-Saclay, Bat. 141 SEN Saclay, F-91191, Gif-sur-Yvette (France); Naumann, C.L.; Nayman, P. [LPNHE, Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Barre 12-22, 1er etage, 4 place Jussieu, 75252 Paris (France); Ribo, M. [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); and others


    The NECTAr collaboration's FE option for the camera of the CTA is a 16 bits and 1-3 GS/s sampling chip based on analog memories including most of the readout functions. This works describes the input amplifiers of the NECTAr ASIC. A fully differential wideband amplifier, with voltage gain up to 20 V/V and a BW of 400 MHz. As it is impossible to design a fully differential OpAmp with an 8 GHz GBW product in a 0.35 CMOS technology, an alternative implementation based on HF linearized transconductors is explored. The output buffer is a class AB miller operational amplifier, with special non-linear current boost.

  11. The Electron Beam Semiconductor (EBS) amplifier (United States)

    True, R. M.; Baxendale, J. F.


    The Electron Beam Semiconductor (EBS) concept has existed for three decades; but only within the last decade has an active, well-defined program been underway to develop devices that can operate as high-power radio frequency(RF) amplifiers, fast risetime switches, and current and voltage pulse amplifiers. This report discusses the test procedures, data and results of reliability testing of RF and video pulse EBS amplifiers at Electronics Research and Development Command (ERADCOM), Fort Monmouth, New Jersey. Also, the experimental analysis of the series connected diode EBS device is described in detail. Finally, the report concludes with a discussion of the state-of-the-art of EBS and future trends of the technology.

  12. Design Of A Doherty Power Amplifier For GSM Systems

    Directory of Open Access Journals (Sweden)

    Saad Wasmi Osman


    Full Text Available This paper presents the design and analysis of Doherty power amplifier. The Doherty amplifier is used in  a base station for mobile system because of its high efficiency. The class AB power amplifier used in the configuration of the main and auxiliary amplifier. The result obtained shows that the Doherty power amplifier can be used on a wide band spectrum, the amplifier works at 900MHz and has very good power added efficiency (PAE and gain. The amplifier can also work at 1800MHz at input power greater than 20dBm. 


    Directory of Open Access Journals (Sweden)

    Vidyadhar Bangal


    Full Text Available Hemorrhage in pregnancy is the leading cause of maternal mortality in developing countries. Internaliliac artery ligation is one of the life saving procedures in intractable pelvic hemorrhage. Althougheffective, the procedure is not commonly performed by obstetricians and gynecologists. Present paper aims at sharing author’s experience about usefulness of this surgical procedure in arrest of pelvic hemorrhage and to remove the inhibition among practicing gynecologists regarding this procedure.Fifty four cases of pelvic hemorrhage were managed by internal iliac artery ligation over 15 year period at tertiary care center. Hemorrhage could be arrested in all cases.

  14. Coronary ligation reduces maximum sustained swimming speed in Chinook salmon, Oncorhynchus tshawytscha

    DEFF Research Database (Denmark)

    Farrell, A P; Steffensen, J F


    The maximum aerobic swimming speed of Chinook salmon (Oncorhynchus tshawytscha) was measured before and after ligation of the coronary artery. Coronary artery ligation prevented blood flow to the compact layer of the ventricular myocardium, which represents 30% of the ventricular mass, and produced...... a statistically significant 35.5% reduction in maximum swimming speed. We conclude that the coronary circulation is important for maximum aerobic swimming and implicit in this conclusion is that maximum cardiac performance is probably necessary for maximum aerobic swimming performance....

  15. Bis-ligated Ti and Zr complexes of chelating N-heterocyclic carbenes

    KAUST Repository

    El-Batta, Amer


    In this communication we report the synthesis of novel titanium and zirconium complexes ligated by bidentate "salicylaldimine-like" N-heterocyclic carbenes (NHC). Double addition of the NHC chelate to either TiCl4(thf)2 or ZrCl4 forms bis-ligated organometallic fragments with a distorted octahedral geometry. These complexes are rare examples of group IV transition-metal NHC adducts. Preliminary catalytic tests demonstrate that in the presence of methylaluminoxane (MAO) these complexes are useful initiators for the polymerization of ethylene and the copolymerization of ethylene with norbornene and 1-octene. © 2011 Elsevier B.V. All rights reserved.

  16. Impairment of the organization of locomotor and exploratory behaviors in bile duct-ligated rats

    DEFF Research Database (Denmark)

    Leke, Renata; de Oliveira, Diogo L; Mussulini, Ben Hur M.;


    female Wistar rats underwent common bile duct ligation (BDL rats) or the manipulation of common bile duct without ligation (control rats). Six weeks after surgery, control and BDL rats underwent open-field, plus-maze and foot-fault behavioral tasks. The BDL rats developed chronic liver failure...... from the control rats for the elevated plus-maze and foot-fault tasks. Therefore, the BDL rats demonstrated disturbed spontaneous locomotor and exploratory activities as a consequence of altered spatio-temporal organization of behavior....


    Directory of Open Access Journals (Sweden)



    Full Text Available Internal iliac artery (Hypogastric supplies the pelvic viscera. Bilateral ligation of the internal iliac arteries is a safe, rapid and very effective method of controlling bleeding from genital tract. It is also helpful in massive broad ligament hematoma, in torn vessels retracted within th e broad ligament, and even in postoperative hemorrhage after abdominal or vaginal hysterectomy where there are no definitive bleeding points detectable. Bilateral ligation of internal iliac arteries is also helpful in life threatening hemorrhagic condition s like postpartum hemorrhage, placenta previa, cervical and vaginal tear, cervical pregnancy and uterine rupture etc.

  18. An equation for calculating the volumetric ratios required in a ligation reaction. (United States)

    Cranenburgh, R M


    The ligation of two DNA fragments to create a new plasmid DNA molecule is a key reaction in molecular biology. Where the fragment lengths and concentrations are known, existing equations allow the desired relative molar ratio to be calculated, but this must then be related to the required volumes. Further calculations are then necessary if the maximum available volume is to consist of DNA solutions. The equation presented here allows the simple calculation of volumes of DNA solutions required to obtain a desired molar insert-to-vector ratio, and these can comprise all of the available volume in a ligation if required, thus maximising the yield of the recombinant plasmid.

  19. Associated Liver Partition and Portal Vein Ligation (ALPPS) vs Selective Portal Vein Ligation (PVL) for Staged Hepatectomy in a Rat Model. Similar Regenerative Response? (United States)

    García-Pérez, Rocío; Revilla-Nuin, Beatriz; Martínez, Carlos M; Bernabé-García, Angel; Baroja Mazo, Alberto; Parrilla Paricio, Pascual


    Associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a two-stage hepatectomy technique which can be associated with a hypertrophic stimulus on the future liver remnant (FLR) stronger than other techniques--such as portal vein ligation (PVL). However, the reason of such hypertrophy is still unclear, but it is suggested that liver transection combined with portal vein ligation (ALPPS) during the first stage of this technique may play a key role. The aim of this study is to compare the hypertrophic stimulus on the FLR and the clinical changes associated with both ALPPS and PVL in a rat surgical model. For this purpose, three groups of SD rats were used, namely ALPPS (n = 30), PVL (n = 30) and sham-treated (n = 30). The second stage of ALPPS (hepatectomy of the atrophic lobes), was performed at day 8. Blood and FLR samples were collected at 1, 24, 48 hours, 8 days and 12 weeks after the surgeries. ALPPS provoked a greater degree of hypertrophy of the FLR than the PVL at 48 hours and 8 days (pstimulus at 12 weeks, with a higher expression of HGF and TGF-β (presponse seems to be leaded by a complex interaction between pro-mitogenic (IL-6, HGF, TNF-α) and antiproliferative (IL1-β and TGF-β) cytokines.

  20. Implementation of Digital Lock-in Amplifier (United States)

    Bhattacharyya, Sabyasachi; Nasir Ahmed, Ragib; Bijoy Purkayastha, Basab; Bhattacharyya, Kaustubh


    The recovery of signal under the presence of noise is utmost essential for proper communication. The signals corrupted due to noise can be recovered using various techniques. However the weak signals are more prone to noise and hence they can be easily degraded due to noise. In such cases, a digital lock-in amplifier becomes an essential device for recovery of such weak signals. Keeping the cost, speed and other considerations, we will present the implementation of digital lock-in amplifier and how it recovers the weak signal under extreme noisy conditions.

  1. Double Clad Er-doped Fiber Amplifier

    Institute of Scientific and Technical Information of China (English)

    FU Yong-jun; MAO Xiang-qiao; WEI Huai; LI jian


    Presented is a theoretical study of double-clad Er-doped fiber power amplifier(EDFA). Two kinds of double clad fibers(DCF) with rectangular and "flower" inner clad shapes are studied, and these fibers have different coupling constants and propagation losses. We calculate the effective pump power absorption ratio along the fiber with different coupling constants from the first cladding to the doped core and with different propagation losses for the power in the inner cladding. Then the gains of the double clad Er-doped fiber amplifiers versus fiber lengths are calculated using the EDFA model based on propagation and rate equations of a homogeneous, two-level medium.

  2. Optimization of Pr3+:ZBLAN fiber amplifiers


    Pedersen, B.; Miniscalco, J. W.; Quimby, R. S.


    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

  3. Dynamic range meter for radiofrequency amplifiers

    Directory of Open Access Journals (Sweden)

    Drozd S. S.


    Full Text Available The new measurement setup having increased on 20…30 dB the own dynamic range in comparison with the standard circuit of the dynamic range meter is offered and the rated value of an error bringing by setup in the worst case does not exceed ± 2,8 dB. The measurement setup can be applied also to determinate levels of intermodulation components average power amplifiers and powerful amplifiers of a low-frequency at replacement of the quartz filter on meeting low-frequency the LC-filter and the spectrum analyzer.

  4. Analysis of bipolar and CMOS amplifiers

    CERN Document Server

    Sodagar, Amir M


    The classical approach to analog circuit analysis is a daunting prospect to many students, requiring tedious enumeration of contributing factors and lengthy calculations. Most textbooks apply this cumbersome approach to small-signal amplifiers, which becomes even more difficult as the number of components increases. Analysis of Bipolar and CMOS Amplifiers offers students an alternative that enables quick and intuitive analysis and design: the analysis-by-inspection method.This practical and student-friendly text demonstrates how to achieve approximate results that fall within an acceptable ran

  5. Linear Amplifier Model for Optomechanical Systems

    CERN Document Server

    Botter, Thierry; Brahms, Nathan; Schreppler, Sydney; Stamper-Kurn, Dan M


    We model optomechanical systems as linear optical amplifiers. This provides a unified treatment of diverse optomechanical phenomena. We emphasize, in particular, the relationship between ponderomotive squeezing and optomechanically induced transparency, two foci of current research. We characterize the amplifier response to quantum and deliberately applied fluctuations, both optical and mechanical. Further, we apply these results to establish quantum limits on external force sensing both on and off cavity resonance. We find that the maximum sensitivity attained on resonance constitutes an absolute upper limit, not surpassed when detuning off cavity resonance. The theory can be extended to a two-sided cavity with losses and limited detection efficiency.

  6. Operational amplifier circuits analysis and design

    CERN Document Server

    Nelson, J C C


    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


    Institute of Scientific and Technical Information of China (English)

    Chen Keneng; Yang Guoliang; Xie Wei; Hu Minbo; Feng Ruiqing; Shi Xiaotian


    Objective: Traditional method of closing bronchial stumps after lobectomy was whole layer suture by hand or by stapler. Little is known about the ligated bronchial stump following lobectomy. To evaluate the characteristics of ligation method for closing bronchial stumps. Methods: In this study 90 lobectomies on 15 mongrel dogs and 75 bronchial stump models on fresh cadaver bronchus were performed. Multivariables comparison experimental studies were made on the results of three different closing methods: simple ligation,manual suture and stapling. Results: In the ligation group, the operation time was significantly shortened (P<0.01). The depth of stump cavity between ligation group and suture group was of no difference significantly (P>0.05). The resistance against intrabronchial pressure was greater in the ligation group than in the suture group (P<0.01). Pathological studies illustrated earlier healing of mucosal membrane with milder inflammatory reactions.In clinical practice, 121 lobectomies were successfully performed with simple ligation of the stumps.Conclusion: Simple ligation is a safe, reliable, simple, and applicable method for closing bronchial stump following lobectomies.

  8. Swimming performance, venous oxygen tension and cardiac performance of coronary-ligated rainbow trout, Oncorhynchus mykiss, exposed to progressive hypoxia

    DEFF Research Database (Denmark)

    Steffensen, J F; Farrell, A P


    (Pva) increased significantly with hypoxic swimming in sham-operated fish, there was no such increase in coronary-ligated fish. In addition, cardiac arrhythmias occurred in coronary-ligated fish at fatigue, and these fish were slower to recover from exhaustion. We believe that the venous PO2 threshold...

  9. Kinetic characterization of on-chip DNA ligation on dendron-coated surfaces with nanoscaled lateral spacings (United States)

    Kim, Eung-Sam; Lee, Namgyu; Park, Joon Won; Choi, Kwan Yong


    We analyzed the enzymatic profiles of on-chip DNA ligation as we controlled the lateral spacing of surface-immobilized DNA substrates using dendron molecules with different sizes at the nanoscale. Enzymatic on-chip DNA ligation was performed on the dendron-coated surface within 20 min with no need for post-ligation gel electrophoresis. The enzymatic DNA repair was assessed by the fluorescence intensity at the repaired DNA duplex after thermally dissociating the unligated Cy3-labeled DNA from the DNA duplex, in which the Cy3-labeled DNA was hybridized prior to the on-chip DNA ligation. The rate of the nick-sealing reaction on the 27-acid dendron surface was 3-fold higher than that on the 9-acid dendron surface, suggesting that the wider lateral spacing determined by the larger dendron molecule could facilitate the access of DNA ligase to the nick site. The performance of on-chip DNA ligation was dropped to 10% and 3% when the nick was replaced by one- and two-nucleotide-long gaps, respectively. The 5‧ terminal phosphorylation of DNA strands by polynucleotide kinase and the on-chip DNA cleavage by endonucleases were also quantitatively monitored throughout the on-chip DNA ligation on the dendron-coated surface. A better understanding of the enzymatic kinetics of on-chip DNA ligation will contribute to a more reliable performance of various on-chip DNA ligation-based assays.

  10. A novel DNA deletion-ligation reaction catalyzed in vitro by a developmentally controlled activity from Tetrahymena cells. (United States)

    Robinson, E K; Cohen, P D; Blackburn, E H


    Developmentally controlled genomic deletion-ligations occur during ciliate macronuclear differentiation. We have identified a novel activity in Tetrahymena cell-free extracts that efficiently catalyzes a specific set of intramolecular DNA deletion-ligation reactions. When synthetic DNA oligonucleotide substrates were used, all the deletion-ligation products resembled those formed in vivo in that they resulted from deletions between pairs of short direct repeats. The reaction is ATP-dependent, salt-sensitive, and strongly influenced by the oligonucleotide substrate sequence. The deletion-ligation activity has an apparent size of 200-500 kd, no nuclease-sensitive component, and is highly enriched in cells developing new macronuclei. The temperature inactivation profile of the activity parallels the temperature lethality profile specific for Tetrahymena cells developing new macronuclei. We suggest that this deletion-ligation activity carries out the genomic deletions in developing macronuclei in vivo.

  11. A cascade amplification strategy based on rolling circle amplification and hydroxylamine amplified gold nanoparticles enables chemiluminescence detection of adenosine triphosphate. (United States)

    Wang, Ping; Zhang, Tonghuan; Yang, Taoyi; Jin, Nan; Zhao, Yanjun; Fan, Aiping


    A highly sensitive and selective chemiluminescent (CL) biosensor for adenosine triphosphate (ATP) was developed by taking advantage of the ATP-dependent enzymatic reaction (ATP-DER), the powerful signal amplification capability of rolling circle amplification (RCA), and hydroxylamine-amplified gold nanoparticles (Au NPs). The strategy relies on the ability of ATP, a cofactor of T4 DNA ligase, to trigger the ligation-RCA reaction. In the presence of ATP, the T4 DNA ligase catalyzes the ligation reaction between the two ends of the padlock probe, producing a closed circular DNA template that initiates the RCA reaction with phi29 DNA polymerase and dNTP. Therein, many complementary copies of the circular template can be generated. The ATP-DER is eventually converted into a detectable CL signal after a series of processes, including gold probe hybridization, hydroxylamine amplification, and oxidative gold metal dissolution coupled with a simple and sensitive luminol CL reaction. The CL signal is directly proportional to the ATP level. The results showed that the detection limit of the assay is 100 pM of ATP, which compares favorably with those of other ATP detection techniques. In addition, by taking advantage of ATP-DER, the proposed CL sensing system exhibits extraordinary specificity towards ATP and could distinguish the target molecule ATP from its analogues. The proposed method provides a new and versatile platform for the design of novel DNA ligation reaction-based CL sensing systems for other cofactors. This novel ATP-DER based CL sensing system may find wide applications in clinical diagnosis as well as in environmental and biomedical fields.

  12. Feedback analysis of transimpedance operational amplifier circuits

    DEFF Research Database (Denmark)

    Bruun, Erik


    The transimpedance or current feedback operational amplifier (CFB op-amp) is reviewed and compared to a conventional voltage mode op-amp using an analysis emphasizing the basic feedback characteristics of the circuit. With this approach the paradox of the constant bandwidth obtained from CFB op...

  13. High-Performance Operational and Instrumentation Amplifiers

    NARCIS (Netherlands)

    Shahi, B.


    This thesis describes techniques to reduce the offset error in precision instrumentation and operational amplifiers. The offset error which is considered a major error source associated with gain blocks, together with other errors are reviewed. Conventional and newer approaches to remove offset and

  14. Holographic preamplifier for a quantum amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Zemskov, K.I.; Kazarian, M.A.; Orlova, N.G.; Liuksiutov, S.F.; Odulov, S.G.


    Successive amplification of a weak optical signal was realized experimentally in holographic and quantum amplifiers. The signal was a coherent one with an intensity less than the actual noise of the copper-vapor active medium; the technique involved the use of a coherent holographic preamplifier based on a lithium niobate/sodium photorefractive crystal. 8 references.

  15. Optimization of Pr3+:ZBLAN fiber amplifiers

    DEFF Research Database (Denmark)

    Pedersen, B.; Miniscalco, J. W.; Quimby, R. S.


    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...

  16. Predistortion of a Bidirectional Cuk Audio Amplifier

    DEFF Research Database (Denmark)

    Birch, Thomas Hagen; Nielsen, Dennis; Knott, Arnold;


    Some non-linear amplifier topologies are capable of providing a larger voltage gain than one from a DC source, which could make them suitable for various applications. However, the non-linearities introduce a significant amount of harmonic distortion (THD). Some of this distortion could be reduce...


    design and synthesis of broadband varactor parametric amplifiers. The circuit considered in this thesis is that of linear variable capacitors embedded...second and more important inherent property is that, due to the frequency-coupling action of the variable capacitor , the scattering coefficient at the

  18. Offset Correction Techniques for Voltage Sense Amplifiers

    NARCIS (Netherlands)

    Groeneveld, S.


    This report deals with offset correction techniques for voltage sense amplifiers and is divided into two different parts: 1) mismatch and 2) offset correction techniques. First a literature study is done on the subject mismatch with specially focus on the future. Mismatch of a transistor is determin

  19. Ultra-low Voltage CMOS Cascode Amplifier

    DEFF Research Database (Denmark)

    Lehmann, Torsten; Cassia, Marco


    In this paper, we design a folded cascode operational transconductance amplifier in a standard CMOS process, which has a measured 69 dB DC gain, a 2 MHz bandwidth and compatible input- and output voltage levels at a 1 V power supply. This is done by a novel Current Driven Bulk (CDB) technique...

  20. Ligation of mouse L4 and L5 spinal nerves produces robust allodynia without major motor function deficit. (United States)

    Ye, Gui-Lan; Savelieva, Katerina V; Vogel, Peter; Baker, Kevin B; Mason, Sara; Lanthorn, Thomas H; Rajan, Indrani


    Spinal nerve L5/L6 ligation (SNL) in rats has become the standard for mechanistic studies of peripheral neuropathy and screening for novel analgesics. Conventional SNL in our hybrid mice resulted in a wide range of allodynia. Anatomical evaluation indicated that a variable number of lumbar vertebrae existed, resulting in L4/L5 or L5/L6 being ligated. Surprisingly, L4/L5 ligation did not result in ipsilateral hind limb paralysis and produced robust allodynia. Following a recent report that the mouse L4 neural segment is homologous with rat L5 we generated L4, L5 or both L4 and L5 (L4/L5) ligations in C57 mice after establishing a modified set of surgical landmarks. In contrast to rats, L4 ligation in these mice did not result in hind limb paralysis. Robust allodynia was observed in all three ligation groups. Nerve degeneration confirmed that L4 and L5, respectively, are primary contributors to the tibial and sural branches of the sciatic nerve in mice. A larger von Frey sensitive area reflected the wider distribution of Wallerian degeneration in the hindlimb of L4- compared to L5-ligated mice. Ligation of mouse L4 and L5 spinal nerves produces consistent, robust neuropathic pain behaviors and is suitable as a model for investigating mechanisms of neuropathic pain and for testing of novel analgesics. Gabapentin, used as a validation drug in neuropathic pain models and as a reference compound for novel analgesics, significantly reduced allodynia in the mice tested (L4/L5 ligations). Given the ease of surgery, robust allodynia, and larger von Frey sensitive area, we conclude that combined ligation of spinal nerves L4 and L5 optimizes the SNL model in mice.


    Directory of Open Access Journals (Sweden)

    Gulsen KESKiN


    We believe that VLBW preterm infants by having multiple system failure may have PDA ligation in operating room if there is no optimum conditions in ICU by obtaining safe transport, performing ketamine in anesthesia induction and maintenance. [J Contemp Med 2016; 6(1.000: 47-50

  2. Aneurysm after surgical ligation of patent ductus arteriosus: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Gyu; Yang, Sang Kyu; Chi, Jung Ik; Lee, Chang Jun [National Medical Center, Seoul (Korea, Republic of)


    Patent ductus arteriosus (PDA) is one of the most common congenital heart diseases. A rare complication occurring after its surgical treatment is the development of an aneurysm, and we report the radiologic findings in a case in which this occurred after surgical ligation.


    Energy Technology Data Exchange (ETDEWEB)

    Camarero, J A; Mitchell, A R


    C-terminal peptide {alpha}-thioesters are valuable intermediates in the synthesis/semisynthesis of proteins by native chemical ligation. They are prepared either by solid-phase peptide synthesis (SPPS) or biosynthetically by protein splicing techniques. The present paper reviews the different methods available for the chemical synthesis of peptide {alpha}-thioesters using Fmoc-based SPPS.

  4. Histamine receptors expressed in circulating progenitor cells have reciprocal actions in ligation-induced arteriosclerosis. (United States)

    Yamada, Sohsuke; Wang, Ke-Yong; Tanimoto, Akihide; Guo, Xin; Nabeshima, Atsunori; Watanabe, Takeshi; Sasaguri, Yasuyuki


    Histamine is synthesized as a low-molecular-weight amine from L-histidine by histidine decarboxylase (HDC). Recently, we demonstrated that carotid artery-ligated HDC gene-deficient mice (HDC(-/-)) showed less neointimal formation than wild-type (WT) mice, indicating that histamine participates in the process of arteriosclerosis. However, little is known about the roles of histamine-specific receptors (HHRs) in arteriosclerosis. To define the roles of HHRs in arteriosclerosis, we investigated intimal remodeling in ligated carotid arteries of HHR-deficient mice (H1R(-/-) or H2R(-/-)). Quantitative analysis showed that H1R(-/-) mice had significantly less arteriosclerogenesis, whereas H2R(-/-) mice had more, as compared with WT mice. Bone marrow transplantation from H1R(-/-) or H2R(-/-) to WT mice confirmed the above observation. Furthermore, the increased expression of monocyte chemoattractant protein (MCP-1), platelet-derived growth factor (PDGF), adhesion molecules and liver X receptor (LXR)-related inflammatory signaling factors, including Toll-like receptor (TLR3), interleukin-1 receptor (IL-1R) and tumor necrosis factor receptor (TNF-R), was consistent with the arteriosclerotic phenotype of H2R(-/-) mice. Peripheral progenitor cells in H2R(-/-) mice accelerate ligation-induced arteriosclerosis through their regulation of MCP-1, PDGF, adhesion molecules and LXR-related inflammatory signaling factors. In contrast, peripheral progenitor cells act to suppress arteriosclerosis in H1R(-/-) mice, indicating that HHRs reciprocally regulate inflammation in the ligation-induced arteriosclerosis.

  5. Ligation of pork skin gelatin with glucose moieties affects the junction zones in gelled networks

    NARCIS (Netherlands)

    Baigts Allende, Diana; Jongh, de H.H.J.


    This study aims to investigate the role of the ligation of steric moieties on the formation of junction zones during network formation of gelatin gels. The molecular conformational propensities, heat stability and mechanical properties of gradually chemically modified pork skin gelatin have been

  6. Comparative study of proton pump inhibitors on dexamethasone plus pylorus ligation induced ulcer model in rats

    Directory of Open Access Journals (Sweden)

    Thippeswamy A. H. M.


    Full Text Available The present study was designed to compare ulcer protective effect of proton pump inhibitors viz. omeprazole, rabeprazole and lansoprazole against dexamethasone plus pylorus ligation induced ulcer model. Dexamethasone (5 mg/kg was used as an ulcerogen. Dexamethasone suspended in 1% CMC in water was given orally to all the rats 15 min after the pylorus ligation. Omeprazole (20 mg/kg, rabeprazole (20 mg/kg, and lansoprazole (20 mg/kg were administered by oral route 30 min prior to ligation was used for ulcer protective studies, gastric secretion and mucosal studies. Effects of proton pump inhibitors were determined by the evaluation of various biochemical parameters such as ulcer index, free and total acidity, gastric pH, mucin, pepsin and total proteins. Oral administration of proton pump inhibitors showed significant reduction in gastric acid secretion and ulcer protective activity against dexamethasone plus pylorus ligation induced ulcer model. The % protection of omeprazole, rabeprazole and lansoprazole was 84.04, 89.36 and 79.78, respectively. Rabeprazole significantly inhibited the acid-pepsin secretion and increased the gastric mucin secretion. The observations made in the present study suggest that rabeprazole is the most effective gastric antisecretory and ulcer healing agent as compared to omeprazole and lansoprazole.

  7. Gingival response in orthodontic patients: Comparative study between self-ligating and conventional brackets. (United States)

    Folco, Alejandra A; Benítez-Rogé, Sandra C; Iglesias, Marina; Calabrese, Diana; Pelizardi, Cristina; Rosa, Alcira; Brusca, Marisa I; Hecht, Pedro; Mateu, María E


    Orthodontic brackets contribute to the accumulation of bacterial plaque on tooth surfaces because they hinder oral hygiene. In contrast to conventional brackets, self-ligating brackets do not require additional parts to support the arches, thus improving dental hygiene. The aim of this study was to compare the gingival response in orthodontic patients wearing self-ligating or conventional brackets. A sample of 22 patients aged 16 to 30 years was divided into two groups: Group A, treated with selfligating brackets (Damon system) and Group B, treated with conventional brackets (Roth technique). The following were assessed during the treatment: Plaque Index (PI), Gingival Index (GI) and Probing Depth (PD), and sub-gingival samples were taken from teeth 14/24 for microbiological observation. No statistically significant difference was found between Groups A and B; p>0.05 (sign-ranked) or between PI, GI and PD at the different times (Friedman's Analysis of Variance), even though the indices were found to increase at 14 days, particularly for self-ligating brackets. The quantity and quality of microorganisms present were compatible with health on days 0, 28 and 56. As from day 14 there is a predominance of microbiota compatible with gingivitis in both groups. In the samples studied, orthodontic treatment increases bacterial plaque and inflammatory gingival response, but gingival-periodontal health can be maintained with adequate basic therapy. Self-ligating and conventional brackets produced similar gingival response.

  8. Catecholamine-resistant hypotension and myocardial performance following patent ductus arteriosus ligation.

    LENUS (Irish Health Repository)

    Noori, S


    Objective:We performed a multicenter study of preterm infants, who were about to undergo patent ductus arteriosus ligation, to determine whether echocardiographic indices of impaired myocardial performance were associated with subsequent development of catecholamine-resistant hypotension following ligation.Study Design:A standardized treatment approach for hypotension was followed at each center. Infants were considered to have catecholamine-resistant hypotension if their dopamine infusion was >15 μg kg(-1)min(-1). Echocardiograms and cortisol measurements were obtained between 6 and 14 h after the ligation (prior to the presence of catecholamine-resistant hypotension).Result:Forty-five infants were enrolled, 10 received catecholamines (6 were catecholamine-responsive and 4 developed catecholamine-resistant hypotension). Catecholamine-resistant hypotension was not associated with decreased preload, shortening fraction or ventricular output. Infants with catecholamine-resistant hypotension had significantly lower levels of systemic vascular resistance and postoperative cortisol concentration.Conclusion:We speculate that low cortisol levels and impaired vascular tone may have a more important role than impaired cardiac performance in post-ligation catecholamine-resistant hypotension.Journal of Perinatology advance online publication, 14 August 2014; doi:10.1038\\/jp.2014.151.

  9. Ligation of the thoracic duct for the treatment of chylothorax in heart diseases

    Directory of Open Access Journals (Sweden)

    Pêgo-Fernandes Paulo M.


    Full Text Available In children, chylothorax occurs mainly after cardiac and thoracic surgeries. One of the recommended postsurgery treatments is ligation of the thoracic tract, when all other conservative treatments have failed. We report 4 cases of chylothorax in patients who were successfully treated with this approach, which resulted in a decrease in pleural drainage without recurrent chylothorax.

  10. A revised mechanism for the α-ketoacid hydroxylamine amide forming ligations. (United States)

    Patil, Mahendra


    Computational investigations of the α-ketoacid-hydroxylamine amide-forming (KAHA) ligation of O-unsubstituted (type-I) and O-benzoyl substituted (type-II) hydroxylamine have revealed a distinct mechanistic pathway for the KAHA ligation reactions. Instead of a pathway involving lactone and oxiridine intermediates for the reaction of O-unsubstituted hydroxylamine and ketoacids (type-I KAHA), as had been proposed in the experimental studies, the computational results favor the pathway which involves migration of the hydroxy group (-OH) to the adjacent carbon in one of the key steps. The new pathway for the type I KAHA reaction explains the distribution of the (18)O label in the final product (amide) that is observed in (18)O labeling experiments of type-I ligation reaction. A coherent mechanistic course is also identified for the reaction of O-benzoyl substituted hydroxylamine and ketoacid (type II KAHA) reactions. The proposed pathway for the type-II KAHA ligation reaction proceeds with the retention of an oxygen atom of the keto group of ketoacids rather than hydroxylamine in the final product (amide). These findings are consistent with the results of (18)O labeling experiments performed by Bode and coworkers on the KAHA reactions.

  11. Electronic Configuration of Five-Coordinate High-Spin Pyrazole-Ligated Iron(II) Porphyrinates (United States)

    Hu, Chuanjiang; Noll, Bruce C.; Schulz, Charles E.; Scheidt, W. Robert


    Pyrazole, a neutral nitrogen ligand and an isomer of imidazole, has been used as a fifth ligand to prepare two new species, [Fe(TPP)(Hdmpz)] and [Fe(Tp-OCH3PP)(Hdmpz)] (Hdmpz = 3,5-dimethylpyrazole), the first structurally characterized examples of five-coordinate iron(II) porphyrinates with a nonimidazole neutral ligand. Both complexes are characterized by X-ray crystallography, and structures show common features for five-coordinate iron(II) species, such as an expanded porphinato core, large equatorial Fe–Np bond distances and a significant out-of-plane displacement of the iron(II) atom. The Fe–N(pyrazole) and Fe–Np bond distances are similar to those in imidazole-ligated species. These suggest that the coordination abilities to iron(II) for imidazole and pyrazole are very similar even though pyrazole is less basic than imidazole. Mössbauer studies reveal that [Fe(TPP)(Hdmpz)] has the same behavior as those of imidazole-ligated species, such as negative quadrupole splitting values and relative large asymmetry parameters. Both the structures and Mössbauer spectra suggest pyrazole-ligated five-coordinate iron(II) porphyrinates have the same electronic configuration as imidazole-ligated species. PMID:21047081

  12. Actual versus theoretical torsional play in conventional and self-ligating bracket systems

    DEFF Research Database (Denmark)

    Dalstra, Michel; Eriksen, Henrik; Bergamini, Chiara;


    Abstract Objective: The aim of this study was to assess the amount of torsional play in 32 commercially available self-ligating and conventional 0·018-inch and 0·022-inch bracket systems in relation to 0·017×0·022-inch and 0·019×0·025-inch stainless steel wires, respectively, and compare the resu...

  13. Opening and closure forces of sliding mechanisms of different self-ligating brackets

    Directory of Open Access Journals (Sweden)

    Paola GANDINI


    Full Text Available Self-ligating brackets engage the wire by means of a slide mechanism. Forces that have to be applied to open and close the sliding mechanism of brackets are still unknown. Objective The aim of this study was to measure and compare the opening and closure forces of different self-ligating brackets. Material and Methods Three different stainless steel self-ligating brackets (Carriere LX, Ortho Organizers; F1000, Leone; Damon Q, Ormco were tested. For each different bracket, 20 maxillary right central incisors and 20 mandibular right central incisors were used. Opening and closure forces were measured using an Instron Universal Testing Machine. Statistical analysis was performed and ANOVA and Tukey tests were carried out. Results Opening forces were registered between 1.1 N and 5.6 N, whereas closure forces were recorded between 1.57 N and 4.87 N. Significant differences were detected among the different brackets and between the two prescriptions tested. Conclusion The knowledge of different opening and closure forces of self-ligating brackets can help the orthodontist in the clinical management of these devices.

  14. Multiplex Ligation-Dependent Probe Amplification of Uveal Melanoma : Correlation with Metastatic Death

    NARCIS (Netherlands)

    Damato, Bertil; Dopierala, Justyna; Klaasen, Annelies; van Dijk, Marcory; Sibbring, Julie; Coupland, Sarah E.


    PURPOSE. To evaluate multiplex ligation-dependent probe amplification (MLPA) of uveal melanoma as a predictive tool for metastatic death. METHODS. Uveal melanoma specimens of 73 patients treated between 1998 and 2000 were included. DNA samples were analyzed with MLPA evaluating 31 loci on chromosome

  15. Minimal access microsurgical ligation of spinal dural arteriovenous fistula with tubular retractor

    Directory of Open Access Journals (Sweden)

    Anderson Chun On Tsang


    Conclusion: With accurate localization of the fistulous point in each patient, only a hemilaminectomy and a small dura opening were required using the tube-assisted technique. This allows direct visualization and ligation of the fistulous point while minimizing postoperative morbidities.

  16. Electronic configuration of five-coordinate high-spin pyrazole-ligated iron(II) porphyrinates. (United States)

    Hu, Chuanjiang; Noll, Bruce C; Schulz, Charles E; Scheidt, W Robert


    Pyrazole, a neutral nitrogen ligand and an isomer of imidazole, has been used as a fifth ligand to prepare two new species, [Fe(TPP)(Hdmpz)] and [Fe(Tp-OCH(3)PP)(Hdmpz)] (Hdmpz = 3,5-dimethylpyrazole), the first structurally characterized examples of five-coordinate iron(II) porphyrinates with a nonimidazole neutral ligand. Both complexes are characterized by X-ray crystallography, and structures show common features for five-coordinate iron(II) species, such as an expanded porphyrinato core, large equatorial Fe-N(p) bond distances, and a significant out-of-plane displacement of the iron(II) atom. The Fe-N(pyrazole) and Fe-N(p) bond distances are similar to those in imidazole-ligated species. These suggest that the coordination abilities to iron(II) for imidazole and pyrazole are very similar even though pyrazole is less basic than imidazole. Mössbauer studies reveal that [Fe(TPP)(Hdmpz)] has the same behavior as those of imidazole-ligated species, such as negative quadrupole splitting values and relative large asymmetry parameters. Both the structures and the Mössbauer spectra suggest pyrazole-ligated five-coordinate iron(II) porphyrinates have the same electronic configuration as imidazole-ligated species.

  17. A balanced wide-band amplifier for microwave applications (United States)

    Panzariu, Mircea; Lupescu, Horia; Dumitrascu, Ana; Tamas, Razvan D.


    Due to its better performance, high fiability and large power capability, balanced amplifier is one of the most popular designs used in narrow band applications. However, with a balanced amplifier in class A operation, the band-pass is still narrow with classical coupler [1]. In this paper, we propose a new method for widen the band-pass and linearity of the amplifier, by using two Lange couplers and by adding two drivers, so that small signal could be amplified [2], [3], [4], [5]. The proposed amplifier works in the 0.9 - 2.4 GHz band, with good performances. We also propose an A class X-band amplifier, with Wilkinson power divider used as a combiner and divider. The amplifier will operate at 9,5 GHz with Continuous Wave (C.W). The two methods were validated by simulating the balanced amplifier with Lange coupler and the balanced amplifier with Wilkinson power divider, in class A operation.

  18. Multi-pass amplifier architecture for high power laser systems (United States)

    Manes, Kenneth R; Spaeth, Mary L; Erlandson, Alvin C


    A main amplifier system includes a first reflector operable to receive input light through a first aperture and direct the input light along an optical path. The input light is characterized by a first polarization. The main amplifier system also includes a first polarizer operable to reflect light characterized by the first polarization state. The main amplifier system further includes a first and second set of amplifier modules. Each of the first and second set of amplifier modules includes an entrance window, a quarter wave plate, a plurality of amplifier slablets arrayed substantially parallel to each other, and an exit window. The main amplifier system additionally includes a set of mirrors operable to reflect light exiting the first set of amplifier modules to enter the second set of amplifier modules and a second polarizer operable to reflect light characterized by a second polarization state.

  19. Prevalence and type of pain during conventional and self-ligating orthodontic treatment. (United States)

    Tecco, Simona; D'Attilio, Michele; Tetè, Stefano; Festa, Felice


    This study investigated the prevalence and type of pain experienced during orthodontic treatment in 30 subjects (12 males, 18 females, aged 12-18 years) with crowding. Fifteen patients were treated with conventional brackets (Victory Series) and 15 with self-ligating brackets (Damon SL II). The first archwire for all patients was a 0.014 inch nickel-titanium (NiTi) archwire with a force of approximately 100 g. Conventional brackets were ligated with elastomeric modules. A visual analogue scale (VAS) was used daily to assess the intensity of pain; the use of pain medication was also reported in a specially designed daybook for a total period of 3 months. Pearson's chi-square was used to investigate the difference between groups in the frequency of pain experience, its nature, and the use of analgesia. Non-parametric statistics (Mann-Whitney U-test) were computed to compare pain intensity between the groups. To investigate reported pain assessments, Friedman's two-way analysis of variance was used and the differences were estimated using Wilcoxon's signed-rank test. The results showed that pain was reported for a period of 9 days after archwire insertion. Patients treated with self-ligating brackets reported the highest pain intensity on the day following placement of the first archwire (VAS mean = 42.6), while those treated with conventional brackets experienced the greatest pain intensity at placement of the first archwire (VAS mean = 52) and after the second orthodontic appointment (VAS mean = 59.6). Analgesics were used by 16.5 per cent of patients treated with self-ligating brackets and by 10 per cent of those treated with conventional brackets, most often during the first 2 days after archwire placement. Patients treated with conventional brackets reported significantly more 'constant' pain than those treated with self-ligating brackets who complained of 'chewing/biting' pain. Pain appears to be common during orthodontic treatment but perhaps less intense when

  20. Inhibition of lung metastasis of osteosarcoma cell line POS-1 transplanted into mice by thigh ligation. (United States)

    Kamijo, Akira; Koshino, Tomihisa; Uesugi, Masaaki; Nitto, Hironori; Saito, Tomoyuki


    Using a model with external ligation of the thigh, the effect of ischemia-reperfusion injury on tumor growth and the activity of lung metastasis was investigated in mice inoculated a spontaneous murine osteosarcoma cell line (POS-1) in vivo. POS-1 cell suspension was inoculated into the right hind footpad of 70 mice. Four weeks after inoculation, the ipsilateral thigh was ligated for 3 h in 15 mice and the contralateral thigh in 15 mice. Another ten mice were inoculated with POS-1 without ligating the thigh. The number of metastatic foci on the lung surface 6 weeks after inoculation was 2.29+/-0.98 (mean+/-SE) foci/lungs in mice with ipsilateral ligation and 6.25+/-2.41 in mice with contralateral ligation, which were significantly lower than control (13.40+/-1.42 in mice no ligation) (P<0.01). The number of metastatic foci on the lung surface in mice with intraperitoneal injection of superoxide dismutase (SOD) and catalase was 3.25+/-0.65 (mean+/-SE) foci/lungs in mice with ligation which was significantly greater than that in mice without SOD and catalase injection 1.29+/-0.97 (P=0.04). Cell viability was 9.12+/-4.07% with 100 microM H(2)O(2) in 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. It revealed that at concentrations of 100 microM H(2)O(2) or higher was cytotoxic to POS-1. In cell invasion assay, the number of invading cells with 10 microM H(2)O(2) was 2.80+/-0.53 cells/field, which was significantly lower than control (5.93+/-0.18) (mean+/-SE), indicating that low-dose H(2)O(2) suppressed invasion of POS-1. These results suggested that reperfusion injury had selective cytotoxicity to POS-1 through producing reactive oxygen species. Activated oxygen was considered to inhibit the regional growth and the ability of lung metastasis of POS-1 cells.

  1. Ligation bias in illumina next-generation DNA libraries: implications for sequencing ancient genomes. (United States)

    Seguin-Orlando, Andaine; Schubert, Mikkel; Clary, Joel; Stagegaard, Julia; Alberdi, Maria T; Prado, José Luis; Prieto, Alfredo; Willerslev, Eske; Orlando, Ludovic


    Ancient DNA extracts consist of a mixture of endogenous molecules and contaminant DNA templates, often originating from environmental microbes. These two populations of templates exhibit different chemical characteristics, with the former showing depurination and cytosine deamination by-products, resulting from post-mortem DNA damage. Such chemical modifications can interfere with the molecular tools used for building second-generation DNA libraries, and limit our ability to fully characterize the true complexity of ancient DNA extracts. In this study, we first use fresh DNA extracts to demonstrate that library preparation based on adapter ligation at AT-overhangs are biased against DNA templates starting with thymine residues, contrarily to blunt-end adapter ligation. We observe the same bias on fresh DNA extracts sheared on Bioruptor, Covaris and nebulizers. This contradicts previous reports suggesting that this bias could originate from the methods used for shearing DNA. This also suggests that AT-overhang adapter ligation efficiency is affected in a sequence-dependent manner and results in an uneven representation of different genomic contexts. We then show how this bias could affect the base composition of ancient DNA libraries prepared following AT-overhang ligation, mainly by limiting the ability to ligate DNA templates starting with thymines and therefore deaminated cytosines. This results in particular nucleotide misincorporation damage patterns, deviating from the signature generally expected for authenticating ancient sequence data. Consequently, we show that models adequate for estimating post-mortem DNA damage levels must be robust to the molecular tools used for building ancient DNA libraries.

  2. Radiological study on the change of duct-ligated parotid gland

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, Takashi (Higashi Nippon Gakuen Univ., Tobetsu, Hokkaido (Japan). School of Dentistry)


    The change of the parotid gland with time following ligation of the main duct was investigated. The duct-ligated parotid gland in rabbit was examined by salivary gland scintigraphy with [sup 99m]Tc-pertechnetate ([sup 99m]TcO[sub 4][sup -]), sialography and microscopic observation. The third day after ligation of the main duct, the outward form of the parotid gland on the static scintigram was not well-defined. On the seventh day, [sup 99m]TcO[sub 4][sup -] accumulation was decreased slightly. On the 14th day, atrophy of the parotid gland occurred. The degree of atrophy produced by ligation increases as the duration of the ligation increases. On the 42nd day, the presence of the parotid gland was not recorded practically. The main duct was dilated on the third day. On the seventh day, the intraglandular ducts were bent and strictured. Disappearance of the peripheral duct and atrophy of the parotid gland parenchyma was observed. On microscopic observation, the intraglandular tributaries and the lumen were dilated on the third day. And the reticular fiber was observed that was irregularly formed in parts. The acinar cells were pressed by large and small dilated lumen on the seventh day. On the 14th day, the collagenous fiber around the acini and the duct was increased still more. In addition, fibrosis of the lobule interspace was observed. The degree of atrophy of the acini and lobule was increased maximally on the 42nd day. These results of the salivary gland scintigraphy closely connected with sialograms and microscopic findings. The parotid gland tissue decreases and changings of the duct system were indicated by these imaging methods in detail. (author).

  3. Routine chest drainage after patent ductus arteriosis ligation is not necessary.

    Directory of Open Access Journals (Sweden)

    Samuel Kai San YAPP


    Full Text Available Introduction: Chest drain insertion after surgical patent ductus arteriosus (PDA ligation creates significant morbidities in terms of pain, pleural space infection, reduced mobility as well as prolonged hospital stay. We investigated the safety and efficacy of performing drainless thoracotomy closure following PDA ligation in a paediatric population. Materials and Methods: Retrospective analysis of data collected from 13 paediatric patients undergoing PDA ligation at RIPAS hospital by a single surgeon over a period of five years (2001 to 2006 was performed. All continuous data were presented as mean ± standard deviation. Results: PDA ligation was performed via a left thoracotomy in 13 pediatric patients with a mean age of 2.24 ± 2.03 years (ten females and three males. Mean duration of the procedures was 67 ± 12 minutes. There was minimal blood loss and no transfusion was required. Postoperatively, ten patients required only oral paracetamol for pain relief. Two patients required additional non steroidal anti-inflammatory drugs (NSAIDs. One patient had one dose of pethidine immediately post-operatively. Post-operative chest radiographs confirmed full expansion of the left lung except in one patient who had a small apical pneumothorax. Two other patients developed mild surgical emphysema despite full expansion of the left lung. All three cases resolved spontaneously after a day. Median post-operative stay was two days. There were no cases of left recurrent nerve injuries and no mortality. Conclusion: Routine chest drainage is not necessary following uncomplicated surgical PDA ligation and patients recovered quicker and are discharge earlier.

  4. Ligation bias in illumina next-generation DNA libraries: implications for sequencing ancient genomes.

    Directory of Open Access Journals (Sweden)

    Andaine Seguin-Orlando

    Full Text Available Ancient DNA extracts consist of a mixture of endogenous molecules and contaminant DNA templates, often originating from environmental microbes. These two populations of templates exhibit different chemical characteristics, with the former showing depurination and cytosine deamination by-products, resulting from post-mortem DNA damage. Such chemical modifications can interfere with the molecular tools used for building second-generation DNA libraries, and limit our ability to fully characterize the true complexity of ancient DNA extracts. In this study, we first use fresh DNA extracts to demonstrate that library preparation based on adapter ligation at AT-overhangs are biased against DNA templates starting with thymine residues, contrarily to blunt-end adapter ligation. We observe the same bias on fresh DNA extracts sheared on Bioruptor, Covaris and nebulizers. This contradicts previous reports suggesting that this bias could originate from the methods used for shearing DNA. This also suggests that AT-overhang adapter ligation efficiency is affected in a sequence-dependent manner and results in an uneven representation of different genomic contexts. We then show how this bias could affect the base composition of ancient DNA libraries prepared following AT-overhang ligation, mainly by limiting the ability to ligate DNA templates starting with thymines and therefore deaminated cytosines. This results in particular nucleotide misincorporation damage patterns, deviating from the signature generally expected for authenticating ancient sequence data. Consequently, we show that models adequate for estimating post-mortem DNA damage levels must be robust to the molecular tools used for building ancient DNA libraries.

  5. Use of rigid tubal ligation scope: Serendipity in laparoscopic common bile duct exploration

    Directory of Open Access Journals (Sweden)

    Manash Ranjan Sahoo


    Full Text Available Aim : To assess the feasibility, safety of rigid tubal ligation scope in laparoscopic common bile duct (CBD exploration. Materials and Methods: Rigid nephroscope was used for laparoscopic CBD exploration until one day we tried the same with the rigid tubal ligation scope, which was passed easily into CBD both proximally and distally visualising the interior of the duct for presence of stone that were removed using endoscopic retrograde cholangiopancreaticography (ERCP basket. This serendipity led us to use this scope for numerous patients from then on. A total of 62 patients, including male and female, underwent laparoscopic CBD exploration after choledochotomy with rigid tubal ligation scope between March 2007 and December 2012 followed by cholecystectomy. All the patients had both cholelithiasis and choledocholithiasis with minimum duct diameter of 12 mm. A total of 48 patients were given T-tube through choledochotomy and closed, and the remaining 14 patients had primary closure of choledochotomy. Results: There were no intra-operative complications in any of the patients like CBD injury or portal vein injury. Post-operatively graded clamping of T-tube was done and was removed after 15 days in the patients who were given T-tube. None had retained the stone after T-tube cholangiography, which was done before removing the tube. Mean duration of follow up was 6 months. No patients had any complaints during the follow up. Conclusion: Laparoscopic CBD exploration is also feasible with rigid tubal ligation scope. With experienced surgeons, CBD injury is very minimal and stone clearance can be achieved in almost all patients. This rigid tubal ligation scope can be an alternative to other rigid and flexible scopes.

  6. Extrahepatic portal venous obstruction: The effects of early ligation of splenic artery during splenectomy

    Directory of Open Access Journals (Sweden)

    Gazula Suhasini


    Full Text Available Aim: To objectively demonstrate the gain in blood volume and blood components following early ligation of splenic artery during splenectomy and splenorenal shunts in children with extra hepatic portal venous obstruction (EHPVO. Methods: Twenty-eight children (20 males and 8 females, mean age: 9.9 (±3.2 years with EHPVO and hypersplenism were recruited. We followed a protocol of systematically locating and ligating the splenic artery first, followed by a 30-minute waiting period to allow the massive spleen to decongest via the splenic vein and venous collaterals and then completing the splenectomy by standard procedure. No intravenous fluid was administered during this 30-minute period. Blood samples were drawn just prior to splenic artery ligation and soon after splenectomy for the estimation of hematological and biochemical parameters. Results: We noticed a highly significant increase in the hemoglobin, hematocrit, leukocyte, platelet, and RBC counts by early ligation of the splenic artery (p < 0.0004. The gain in hemoglobin and hematocrit was equivalent to a transfusion of atleast 100-150 ml of packed RBC. The increase in platelet count was equivalent to a platelet transfusion of atleast 4 units of platelet concentrates in an adult. There is a positive correlation between the splenic weight and the platelet gain (p= 0.0568 and the splenic volume on preoperative imaging and the platelet gain (p= 0.0251. Conclusion: Early ligation of the splenic artery during splenectomy results in passive splenic decongestion and thereby a significant gain in blood components. This protocol appears to be a feasible blood conservation method to avoid blood transfusions in this group of hypersplenic EHPVO patients.

  7. Activation of neurotrophins in lumbar dorsal root probably contributes to neuropathic pain after spinal nerve ligation (United States)

    Kazemi, Abdolreza; Rahmati, Masoud; Eslami, Rasoul; Sheibani, Vahid


    Objective(s): Neurotrophins (NTs) exert various effects on neuronal system. Growing evidence indicates that NTs are involved in the pathophysiology of neuropathic pain. However, the exact role of these proteins in modulating nociceptive signaling requires being defined. Thus, the aim of this study was to evaluate the effects of spinal nerve ligation (SNL) on NTs activation in the lumbar dorsal root. Materials and Methods: Ten male Wistar rats were randomly assigned to two groups: tight ligation of the L5 spinal nerve (SNL: n=5) and Sham (n=5). In order to produce neuropathic pain, the L5 spinal nerve was tightly ligated (SNL). Then, allodynia and hyperalgesia tests were conducted weekly. After 4 weeks, tissue samples were taken from the two groups for laboratory evaluations. Here, Real-Time PCR quantity method was used for measuring NTs gene expression levels. Results: SNL resulted in a significant weight loss in the soleus muscle (Pthermal hyperalgesia thresholds (respectively, P<0.05; P<0.05). Also, NGF, NT-4, NT-3, TrkA, TrkB and TrkC expression were up-regulated following spinal nerve ligation group (respectively, P=0.025, P=0.013, P=0.001, P=0.002, P<0.001, P=001) (respectively, 4.7, 5.2, 7.5, 5.1, 7.2, 6.2 folds). Conclusion: The present study provides new evidence that neuropathic pain induced by spinal nerve ligation probably activates NTs and Trk receptors expression in DRG. However, further studies are needed to better elucidate the role of NTs in a neuropathic pain. PMID:28133521

  8. A new technique of combined endoscopic sclerotherapy and ligation for variceal bleeding

    Institute of Scientific and Technical Information of China (English)

    Radha K. Dhiman; Yogesh K. Chawla


    AIM: To develop a technique of combined endoscopic sclerotherapy and ligation (ESL) in which both techniques of endoscopic sclerotherapy (ES) and endoscopic variceal ligation (EVL) can be optimally used.METHODS: ESL was performed in 10 patients (age 46.4±7.9;9 males, 1 female) with cirrhosis of liver using sclerotherapy needle and Speedband, Superview multiple band ligater (Boston Scientific, Microvasive, Watertown, MA). A single band was placed 5-10 cm proximal to the gastro-esophageal junction over each varix from proximal to distal margin,followed by intravariceal injection of 1.5 % ethoxysclerol (4 ml each) 2 to 3 cm proximal to the gastroesophageal junction on the ligated varices distal to deployed band. EVL was then performed at the injection site. Similarly other varices were also injected and ligated from distal to proximally. In the subsequent sessions, ES alone was performed to sclerose small varices at the gastroesophageal junction.RESULTS: ESL was successfully performed in all patients.A median of 3 (ESL 1, ES 2) sessions (ranged 1-4) were required to eradicate the varices in 9 (90 %) of 10 patients.Recurrence of varices without bleed was seen in 1 patient during a mean follow-up of 10.3 months (ranged 6-15).Two patients died of liver failure. None died of variceal bleeding. None of the patients had procedure related complications.CONCLUSION: ESL may be useful in the fast eradication of esophageal varices. However, randomised controlled trials are required to find out its relative efficacy and impact on variceal recurrence in comparison to ES or EVL.

  9. The warm, rich sound of valve guitar amplifiers (United States)

    Keeports, David


    Practical solid state diodes and transistors have made glass valve technology nearly obsolete. Nevertheless, valves survive largely because electric guitar players much prefer the sound of valve amplifiers to the sound of transistor amplifiers. This paper discusses the introductory-level physics behind that preference. Overdriving an amplifier adds harmonics to an input sound. While a moderately overdriven valve amplifier produces strong even harmonics that enhance a sound, an overdriven transistor amplifier creates strong odd harmonics that can cause dissonance. The functioning of a triode valve explains its creation of even and odd harmonics. Music production software enables the examination of both the wave shape and the harmonic content of amplified sounds.

  10. Low phase noise oscillator using two parallel connected amplifiers (United States)

    Kleinberg, Leonard L.


    A high frequency oscillator is provided by connecting two amplifier circuits in parallel where each amplifier circuit provides the other amplifier circuit with the conditions necessary for oscillation. The inherent noise present in both amplifier circuits causes the quiescent current, and in turn, the generated frequency, to change. The changes in quiescent current cause the transconductance and the load impedance of each amplifier circuit to vary, and this in turn results in opposing changes in the input susceptance of each amplifier circuit. Because the changes in input susceptance oppose each other, the changes in quiescent current also oppose each other. The net result is that frequency stability is enhanced.

  11. Amplified spontaneous emission spectrum and gain characteristic of a two-electrode semiconductor optical amplifier*

    Institute of Scientific and Technical Information of China (English)

    Wang Hanchao; Huang Lirong; Shi Zhongwei


    A two-electrode multi-quantum-well semiconductor optical amplifier is designed and fabricated. The amplified spontaneous emission (ASE) spectrum and gain were measured and analyzed. It is shown that the ASE spectrum and gain characteristic are greatly influenced by the distribution of the injection current density. By changing the injection current density of two electrodes, the full width at half maximum, peak wavelength, peak power of the ASE spectrum and the gain characteristic can be easily controlled.

  12. Non-histone chromosomal proteins HMG1 and 2 enhance ligation reaction of DNA double-strand breaks. (United States)

    Nagaki, S; Yamamoto, M; Yumoto, Y; Shirakawa, H; Yoshida, M; Teraoka, H


    DNA ligase IV in a complex with XRCC4 is responsible for DNA end-joining in repair of DNA double-strand breaks (DSB) and V(D)J recombination. We found that non-histone chromosomal high mobility group (HMG) proteins 1 and 2 enhanced the ligation of linearized pUC119 DNA with DNA ligase IV from rat liver nuclear extract. Intra-molecular and inter-molecular ligations of cohesive-ended and blunt-ended DNA were markedly stimulated by HMG1 and 2. Recombinant HMG2-domain A, B, and (A + B) polypeptides were similarly, but non-identically, effective for the stimulation of DSB ligation reaction. Ligation of single-strand breaks (nicks) was only slightly activated by the HMG proteins. The DNA end-binding Ku protein singly or in combination with the catalytic component of DNA-dependent protein kinase (DNA-PK) as the DNA-PK holoenzyme was ineffective for the ligation of linearized pUC119 DNA. Although the stimulatory effect of HMG1 and 2 on ligation of DSB in vitro was not specific to DNA ligase IV, these results suggest that HMG1 and 2 are involved in the final ligation step in DNA end-joining processes of DSB repair and V(D)J recombination.

  13. Mutational Analysis of Bacterial NAD+-dependent DNA Ligase:Role of Motif Ⅳ in Ligation Catalysis

    Institute of Scientific and Technical Information of China (English)

    Hong FENG


    The bacterial DNA ligase as a multiple domain protein is involved in DNA replication, repair and recombination. Its catalysis of ligation can be divided into three steps. To delineate the roles of amino acid residues in motif Ⅳ in ligation catalysis, site-directed mutants were constructed in a bacterial NAD+-dependent DNA ligase from Thermus sp. TAK16D. It was shown that four conserved residues (D286, G287, V289 and K291) in motif Ⅳ had significant roles on the overall ligation. Under single turnover conditions, the observed apparent rates of D286E, G287A, V289I and K291R mutants were clearly reduced compared with that of WT ligase on both match and mismatch nicked substrates. The effects of D286E mutation on overall ligation may not only be ascribed to the third step. The G287A mutation has a major effect on the second step. The effects of V289I and K291R mutation on overall ligation are not on the third step, perhaps other aspects, such as conformation change of ligase protein in ligation catalysis, are involved. Moreover, the amino acid substitutions of above four residues were more sensitive on mismatch nicked substrate, indicating an enhanced ligation fidelity.

  14. Plaque accumulation and Streptococcus mutans levels around self-ligating bracket clips and elastomeric modules: A randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Dhaval Fadia


    Full Text Available Aim: To determine the effect of two different ligating systems that is, elastomeric modules and self-ligating (SL bracket systems (Smartclip - 3M Unitek with respect to harboring bacterial plaque in fixed orthodontic treatment. Objectives: To assess, evaluate, and compare the amount of plaque accumulation and Streptococcus mutans colonization around elastomeric ligation and SL clips in the smart clip appliance. Materials and Methods: A total of 111 orthodontic patients scheduled for fixed orthodontic treatments were selected for this split maxillary arch study. All the patients were bonded with smart-clip (3M Unitek SL brackets, and the wire was placed into the bracket slots, on the randomly selected hemi arch, elastomeric modules were placed for the study to be conducted. Microbial and periodontal plaque accumulation was recorded at 3-time intervals post ligation. Plaque index-by Silness and Loe, modified Quigely Hein index, bleeding on probing were evaluated, and biofilm was collected from the tooth surface after 30 days and placed in petri dishes containing Mitis Salivarius agar for bacterial culturing. Result: It was observed that the side where ligation was done with elastomeric modules accumulated more plaque and increase in S. mutans colony forming units as compared to the side without external ligation (P < 0.05. Conclusion: Reduced bacterial colonization and better plaque control was seen with SL orthodontic bracket appliance system as compared to conventional ligation method.

  15. Design of an 1800 nm Raman Amplifier

    DEFF Research Database (Denmark)

    Svane, Ask Sebastian; Rottwitt, Karsten

    in the pump power requirement and deteriorated noise properties. Here we demonstrate a Raman amplifier designed for signal wavelengths around 1800 nm. The amplification fiber is an OFS PM Raman fiber, and is pumped by a Raman fiber laser emitting at 1680 nm [4]. The amplifier was pumped co......-polarized and backward, with respect to the singal. In Fig. 2 a measured Raman on/off gain exceeding 9 dB for 285 mW of injected pump power is obtained in a 4.35 km long fiber. A broadband supercontinuum source was used as a signal from 1700 nm to 1900 nm.......Different approaches are being explored to increase the capacity of communication systems [1,2], both long and short range systems. One approach is by exploiting new optical wavelength bands, outside the conventional communication window from 1530 nm to 1625 nm. Hollow core fibers have been...

  16. Behavioral modeling of Digitally Adjustable Current Amplifier

    Directory of Open Access Journals (Sweden)

    Josef Polak


    Full Text Available This article presents the digitally adjustable current amplifier (DACA and its analog behavioral model (ABM, which is suitable for both ideal and advanced analyses of the function block using DACA as active element. There are four levels of this model, each being suitable for simulation of a certain degree of electronic circuits design (e.g. filters, oscillators, generators. Each model is presented through a schematic wiring in the simulation program OrCAD, including a description of equations representing specific functions in the given level of the simulation model. The design of individual levels is always verified using PSpice simulations. The ABM model has been developed based on practically measured values of a number of DACA amplifier samples. The simulation results for proposed levels of the ABM model are shown and compared with the results of the real easurements of the active element DACA.

  17. Noise Gain Features of Fiber Raman Amplifier

    Directory of Open Access Journals (Sweden)

    Georgii S. Felinskyi


    Full Text Available The formation dynamics of the optical noise in a silica single mode fiber (SMF as function of the pump power variation in the counter pumped fiber Raman amplifier (FRA is experimentally studied. The ratio between the power of amplified spontaneous emission and the power of incoherent optical noise is quantitatively determined by detailed analysis of experimental data in the pump powers range of 100–300 mW within the full band of Stokes frequencies, including FRA working wavelengths over the C + L transparency windows. It is found out the maximum of Raman gain coefficient for optical noise does not exceed ~60% of corresponding peak at the gain profile maximum of coherent signal. It is shown that the real FRA noise figure may be considerably less than 3 dB over a wide wavelength range (100 nm at a pump power of several hundreds of mW.

  18. Cryogenic cooling for high power laser amplifiers

    Directory of Open Access Journals (Sweden)

    Perin J.P.


    Full Text Available 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 100 K–170 K with a heat flux of 1 MW*m−2. This paper describes the thermo-mechanical analysis for the design of the amplification laser head, presents a preliminary proposal for the required cryogenic cooling system and finally outlines the gain of cryogenic operation for the efficiency of high pulsed laser.

  19. Linear control of oscillator and amplifier flows* (United States)

    Schmid, Peter J.; Sipp, Denis


    Linear control applied to fluid systems near an equilibrium point has important applications for many flows of industrial or fundamental interest. In this article we give an exposition of tools and approaches for the design of control strategies for globally stable or unstable flows. For unstable oscillator flows a feedback configuration and a model-based approach is proposed, while for stable noise-amplifier flows a feedforward setup and an approach based on system identification is advocated. Model reduction and robustness issues are addressed for the oscillator case; statistical learning techniques are emphasized for the amplifier case. Effective suppression of global and convective instabilities could be demonstrated for either case, even though the system-identification approach results in a superior robustness to off-design conditions.

  20. Fundamentals of fiber lasers and fiber amplifiers

    CERN Document Server

    Ter-Mikirtychev, Valerii (Vartan)


    This book covers the fundamental aspects of fiber lasers and fiber amplifiers, and includes a wide range of material from laser physics fundamentals to state-of-the-art topics in this rapidly growing field of quantum electronics. Emphasis is placed on the nonlinear processes taking place in fiber lasers and amplifiers, their similarities, differences to, and their advantages over other solid-state lasers. The reader will learn basic principles of solid-state physics and optical spectroscopy of laser active centers in fibers, main operational laser regimes, and practical recommendations and suggestions on fiber laser research, laser applications, and laser product development. The book will be useful for students, researchers, and professionals who work with lasers, in the optical communications, chemical and biological industries, etc.

  1. Design and simulation of a gyroklystron amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, M. S., E-mail:; Swati, M. V.; Jain, P. K. [Centre of Research in Microwave Tubes, Department of Electronics Engineering, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005 (India)


    In the present paper, a design methodology of the gyroklystron amplifier has been described and subsequently used for the design of a typically selected 200 kW, Ka-band, four-cavity gyroklystron amplifier. This conceptual device design has been validated through the 3D particle-in-cell (PIC) simulation and nonlinear analysis. Commercially available PIC simulation code “MAGIC” has been used for the electromagnetic study at the different location of the device RF interaction structure for the beam-absent case, i.e., eigenmode study as well as for the electron beam and RF wave interaction behaviour study in the beam present case of the gyroklystron. In addition, a practical problem of misalignment of the RF cavities with drift tubes within the tube has been also investigated and its effect on device performance studied. The analytical and simulation results confirmed the validity of the gyroklystron device design. The PIC simulation results of the present gyroklystron produced a stable RF output power of ∼218 kW for 0% velocity spread at 35 GHz, with ∼45 dB gain, 37% efficiency, and a bandwidth of 0.3% for a 70 kV, 8.2 A gyrating electron beam. The simulated values of RF output power have been found in agreement with the nonlinear analysis results within ∼5%. Further, the PIC simulation has been extended to study a practical problem of misalignment of the cavities axis and drift tube axis of the gyroklystron amplifier and found that the RF output power is more sensitive to misalignments in comparison to the device bandwidth. The present paper, gyroklystron device design, nonlinear analysis, and 3D PIC simulation using commercially available code had been systematically described would be of use to the high-power gyro-amplifier tube designers and research scientists.

  2. High-Performance Operational and Instrumentation Amplifiers


    Shahi, B.


    This thesis describes techniques to reduce the offset error in precision instrumentation and operational amplifiers. The offset error which is considered a major error source associated with gain blocks, together with other errors are reviewed. Conventional and newer approaches to remove offset and low frequency noise are discussed, with a focus on the work of this thesis “Chopper-Stabilized Auto-Zeroed Chopper Instrumentation Amplifiers”. The technique is demonstrated through the application...

  3. Self-amplifying mRNA vaccines. (United States)

    Brito, Luis A; Kommareddy, Sushma; Maione, Domenico; Uematsu, Yasushi; Giovani, Cinzia; Berlanda Scorza, Francesco; Otten, Gillis R; Yu, Dong; Mandl, Christian W; Mason, Peter W; Dormitzer, Philip R; Ulmer, Jeffrey B; Geall, Andrew J


    This chapter provides a brief introduction to nucleic acid-based vaccines and recent research in developing self-amplifying mRNA vaccines. These vaccines promise the flexibility of plasmid DNA vaccines with enhanced immunogenicity and safety. The key to realizing the full potential of these vaccines is efficient delivery of nucleic acid to the cytoplasm of a cell, where it can amplify and express the encoded antigenic protein. The hydrophilicity and strong net negative charge of RNA impedes cellular uptake. To overcome this limitation, electrostatic complexation with cationic lipids or polymers and physical delivery using electroporation or ballistic particles to improve cellular uptake has been evaluated. This chapter highlights the rapid progress made in using nonviral delivery systems for RNA-based vaccines. Initial preclinical testing of self-amplifying mRNA vaccines has shown nonviral delivery to be capable of producing potent and robust innate and adaptive immune responses in small animals and nonhuman primates. Historically, the prospect of developing mRNA vaccines was uncertain due to concerns of mRNA instability and the feasibility of large-scale manufacturing. Today, these issues are no longer perceived as barriers in the widespread implementation of the technology. Currently, nonamplifying mRNA vaccines are under investigation in human clinical trials and can be produced at a sufficient quantity and quality to meet regulatory requirements. If the encouraging preclinical data with self-amplifying mRNA vaccines are matched by equivalently positive immunogenicity, potency, and tolerability in human trials, this platform could establish nucleic acid vaccines as a versatile new tool for human immunization.

  4. Fast Electrocardiogram Amplifier Recovery after Defibrillation Shock

    Directory of Open Access Journals (Sweden)

    Ivan Dotsinsky


    Full Text Available A procedure for fast ECG amplifier recovery after defibrillation shocks was developed and simulated in the MATLAB environment. Exponentially decaying post-shock voltages have been recorded. Signals from the AHA database are taken and mixed with the recorded exponential disturbances. The algorithm applies moving averaging (comb filter on the compound input signal, thereby obtaining the samples of the disturbance. They are currently subtracted from the input signal. The results obtained show that its recovery is practically instantaneous.

  5. Amplifying the Hawking Signal in BECs

    Directory of Open Access Journals (Sweden)

    Roberto Balbinot


    Full Text Available We consider simple models of Bose-Einstein condensates to study analog pair-creation effects, namely, the Hawking effect from acoustic black holes and the dynamical Casimir effect in rapidly time-dependent backgrounds. We also focus on a proposal by Cornell to amplify the Hawking signal in density-density correlators by reducing the atoms’ interactions shortly before measurements are made.

  6. Electrically Pumped Vertical-Cavity Amplifiers

    DEFF Research Database (Denmark)

    Greibe, Tine


    In this work, the design of electrically pumped vertical cavity semiconductor optical amplifiers (eVCAs) for use in a mode-locked external-cavity laser has been developed, investigated and analysed. Four different eVCAs, one top-emitting and three bottom emitting structures, have been designed...... and discussed. The thesis concludes with recommendations for further work towards the realisation of compact electrically pumped mode-locked vertical externalcavity surface emitting lasers....

  7. Transportable setup for amplifier phase fidelity measurements


    Troebs, Michael; Bogan, C.; Barke, S.; Kuehn, G.; Reiche, J.; Heinzel, Gerhard; Danzmann, Karsten


    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 la...

  8. Short wavelength regenerative amplifier free electron lasers


    Dunning, D J; McNeil, B. W. J.; Thompson, N. R.


    In this paper we discuss extending the operating wavelength range of tunable Regenerative Amplifier FELs to shorter wavelengths than current design proposals, notably into the XUV regions of the spectrum and beyond where the reflectivity of broadband optics is very low. Simulation studies are presented which demonstrate the development of good temporal coherence in generic systems with a broadband radiation feedback of less than one part in ten thousand.

  9. Parallel reservoir computing using optical amplifiers. (United States)

    Vandoorne, Kristof; Dambre, Joni; Verstraeten, David; Schrauwen, Benjamin; Bienstman, Peter


    Reservoir computing (RC), a computational paradigm inspired on neural systems, has become increasingly popular in recent years for solving a variety of complex recognition and classification problems. Thus far, most implementations have been software-based, limiting their speed and power efficiency. Integrated photonics offers the potential for a fast, power efficient and massively parallel hardware implementation. We have previously proposed a network of coupled semiconductor optical amplifiers as an interesting test case for such a hardware implementation. In this paper, we investigate the important design parameters and the consequences of process variations through simulations. We use an isolated word recognition task with babble noise to evaluate the performance of the photonic reservoirs with respect to traditional software reservoir implementations, which are based on leaky hyperbolic tangent functions. Our results show that the use of coherent light in a well-tuned reservoir architecture offers significant performance benefits. The most important design parameters are the delay and the phase shift in the system's physical connections. With optimized values for these parameters, coherent semiconductor optical amplifier (SOA) reservoirs can achieve better results than traditional simulated reservoirs. We also show that process variations hardly degrade the performance, but amplifier noise can be detrimental. This effect must therefore be taken into account when designing SOA-based RC implementations.

  10. Charge sensitive amplifies. The state of arts

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Kunishiro [Clear Pulse Co., Tokyo (Japan)


    In the radiation detectors, signals are essentially brought with charges produced by radiation, then it is naturally the best way to use a charge sensitive amplifier (CSA) system to extract those signals. The CSA is thought to be the best amplifier suitable to almost all the radiation detectors, if neglecting economical points of view. The CSA has been only applied to special fields like radiation detection because the concept of `charges` is not so universal against the concepts of `voltage` and `current`. The CSA, however, is low in noise and a high speed amplifier and may be applicable not only to radiation measurement but also piezoelectric devices and also bolometers. In this article, noise in the CSA, basic circuit on the CSA, concepts of `equivalent noise charge` (ENC), a method for the ENC, and importance of the `open-loop gain` in the CSA to achieve better performance of it and how to realize in a practical CSA were described. And, characteristics on a counting rate of the CSA, various circuit used in the CSA, and CSAs which are commercially available at present and special purpose CSAs were also introduced. (G.K.)

  11. Microstrip SQUID amplifiers for quantum information science (United States)

    Defeo, M. P.; Plourde, B. L. T.


    Recent progress in SQUID amplifiers suggests that these devices might approach quantum-limited sensitivity in the microwave range, thus making them a viable option for measurement of superconducting quantum systems. In the microstrip SQUID amplifier configuration, gains of around 20dB are possible at frequencies of several hundred MHz, and the gain is limited by the maximum voltage modulation available from the SQUID. One route for increasing the voltage modulation involves using larger resistive shunts, however maintaining non-hysteretic device operation requires smaller junction capacitances than is possible with conventional photolithographically patterned junctions. Operating at higher frequencies requires a shorter input coil which reduces mutual inductance between the coil and washer and therefore gain. We have fabricated microstrip SQUID amplifiers using submicron Al-AlOx-Al junctions and large shunts. The input coil and SQUID washer are optimized for producing high gain at frequencies in the gigahertz range. Recent measurements of gain and noise temperature will be discussed as well as demonstrations of these devices as a first stage of amplification for a superconducting system

  12. Transistor circuit increases range of logarithmic current amplifier (United States)

    Gilmour, G.


    Circuit increases the range of a logarithmic current amplifier by combining a commercially available amplifier with a silicon epitaxial transistor. A temperature compensating network is provided for the transistor.

  13. Shortcut Access to Peptidosteroid Conjugates: Building Blocks for Solid-Phase Bile Acid Scaffold Decoration by Convergent Ligation

    Directory of Open Access Journals (Sweden)

    Sara Figaroli


    Full Text Available We present three versatile solid-supported scaffold building blocks based on the (deoxycholic acid framework and decorated with handles for further derivatization by modern ligation techniques such as click chemistry, Staudinger ligation or native chemical ligation. Straightforward procedures are presented for the synthesis and analysis of the steroid constructs. These building blocks offer a new, facile and shorter access route to bile acid-peptide conjugates on solid-phase with emphasis on heterodipodal conjugates with defined spatial arrangements. As such, we provide versatile new synthons to the toolbox for bile acid decoration.

  14. Ligation of double-stranded and single-stranded [Oligo(dT)] DNA by vaccinia virus DNA ligase



    Vaccinia virus DNA ligase has been expressed in Escherichia coli, purified, and biochemically characterized. The enzyme ligates double-stranded (ds) DNA substrates with either cohesive or blunt-end termini and the latter reaction is stimulated by PEG. Vaccinia virus DNA ligase can also ligate oligo(dT) when annealed to either a poly(dA) or a poly(rA) backbone and, remarkably, free oligo(dT). This ligation of a single-stranded (ss) substrate is unique among eukaryotic DNA ligases. The enzyme r...

  15. The Dynamics of Semiconductor Optical Amplifiers – Modeling and Applications

    DEFF Research Database (Denmark)

    Mørk, Jesper; Nielsen, Mads Lønstrup; Berg, Tommy Winther


    The importance of semiconductor optical amplifiers is discussed. A semiconductor optical amplifier (SOA) is a semiconductor laser with anti-reflection coated facets that amplifies an injected light signal by means of stimulated emission. SOAs have a number of unique properties that open up...

  16. Microwave parametric amplifiers using externally pumped Josephson junctions

    DEFF Research Database (Denmark)

    Sørensen, O. H.; Mygind, Jesper; Pedersen, Niels Falsig


    Externally pumped parametric amplifiers are discussed. Theory and experiments on the singly degenerate parametric amplifier based on a Josephson junction are presented. Advantages and limitations of the singly degenerate and doubly degenerate parametric amplifiers are discussed. Some plans and pr...... and proposals for future research are presented....

  17. An integrated charge amplifier for a pyroelectric sensor

    NARCIS (Netherlands)

    Setiadi, D.; Armitage, A.; Binnie, T.D.; Regtien, P.P.L.; Sarro, P.M.


    This paper presents an integrated charge amplifier that measures a small charge. This charge is generated by a pyroelectric detector. The charge amplifier consists of a single-stage c-annon source configuration with a passive feedback network. The charge amplifier has a bandwidth of 700 kHz and an o

  18. Polarization of Tapered Semiconductor Travelling-Wave Amplifiers

    Institute of Scientific and Technical Information of China (English)

    Huang Dexiu; Li Hong


    The polarization of a tapered semi-conductor travelling-wave amplifier has been investigated with the transfer matrix method based on convective equation. It is shown that the apparent polarization mode competition exists, and polarization-independent tapered semiconductor travellingwave amplifiers can be obtained through the optimization of amplifier parameters.

  19. Differential transimpedance amplifier circuit for correlated differential amplification (United States)

    Gresham, Christopher A.; Denton, M. Bonner; Sperline, Roger P.


    A differential transimpedance amplifier circuit for correlated differential amplification. The amplifier circuit increase electronic signal-to-noise ratios in charge detection circuits designed for the detection of very small quantities of electrical charge and/or very weak electromagnetic waves. A differential, integrating capacitive transimpedance amplifier integrated circuit comprising capacitor feedback loops performs time-correlated subtraction of noise.

  20. Multiplex ligation-dependent probe amplification (MLPA) screening for exon copy number variation in the calcium sensing receptor gene: no large rearrangements identified in patients with calcium metabolic disorders

    DEFF Research Database (Denmark)

    Nissen, Peter H; Christensen, Signe E; Wallace, Andrew;


    samples were previously found negative for CASR mutations. Multiplex ligation-dependent probe amplification was used to screen the patients for exon copy number variations. Results. All exons were amplified with mean normalised ratios between 0.98 and 1.06. We did not identify any exon copy number......Summary Background. Mutation screening of the CASR by DNA sequencing is commonly used in the diagnosis of disorders of calcium metabolism, such as familial hypocalciuric hypercalcaemia (FHH). Exon copy number variation is not detected by currently used molecular genetic screening methods, and might...... be a genetic cause of inherited forms of hyper- or hypocalcaemia caused by the CASR. Objective. We wanted to further evaluate possible genetic causes for disorders of calcium metabolism, by investigating the prevalence of exon copy number variations, such as large deletions or duplications of the CASR...

  1. Dual-pump wave mixing in semiconductor optical amplifiers: performance enhancement with long amplifiers (United States)

    Tomkos, Ioannis; Zacharopoulos, Ioannis; Syvridis, Dimitrios


    We demonstrate experimentally the improvement of the performance of the dual pump wave mixing scheme in semiconductor optical amplifiers, using long amplifier chips and high optical pump powers. The optical amplifiers used in the experiment had a ridge waveguide structure with bulk active layer and antireflective-coated angled facets. Measurements of the conversion efficiency and SBR as a function of wavelength shift are presented for a wavelength shift of more than 40 nm. The above measurements are carried out for three amplifier lengths (500 micrometers , 1000 micrometers , and 1500 micrometers ) and for different levels of the optical power of the two pumps. It will be shown that an increase in the amplifier length from 500 micrometers to 1500 micrometers results to an increase of more than 25 dB for the efficiency and more than 20 dB for the SBR. This improvement combined with the inherent advantages of the dual pump scheme (almost constant SBR and high efficiency for large wavelength shifts) results in a highly performing wavelength converter/phase conjugator, suitable for many applications.

  2. Microscope-assisted endoscopic interlaminar ligation of spinal arteriovenous fistulas: technical note. (United States)

    Wang, Chen; Chen, Chien-Min; Shen, Fang; Fang, Xiao-Dong; Ying, Guang-Yu; Ren, Yu-Cheng; Yu, Dan-Feng; Zhu, Liang-Liang; Zhu, Yong-Jian; Zhang, Jian-Min


    Spinal dural arteriovenous fistulas (SDAVFs) are the most common type of spinal arteriovenous malformations, and microsurgical ligation is the treatment modality most frequently used for these lesions. Developments in endoscopic techniques have made endoscopy an even less invasive alternative to routine microsurgical approaches in spine surgery, but endoscopic management of SDAVF or other intradural spinal lesions has not been reported to date. The authors describe the use of a microscope-assisted endoscopic interlaminar approach for the ligation of the proximal draining vein of an L-1 SDAVF in a 58-year-old man. A complete cure was confirmed by postoperative angiography. The postoperative course was uneventful, and short-term follow-up showed improvements in the patient's neurological function. The authors conclude that the endoscopic interlaminar approach with microscope assistance is a safe, minimally invasive, innovative technique for the surgical management of SDAVFs in selected patients.

  3. A multiplex ligation detection assay for the characterization of Salmonella enterica strains

    DEFF Research Database (Denmark)

    Aarts, Henk J.M.; Vos, Pieter; Larsson, Jonas T.


    A proof of principle of a multi-target assay for genotyping Salmonella has been developed targeting 62 genomic marker sequences of Salmonella related to pathogenicity. The assay is based on multiplex ligation detection reaction (LDR) followed by customized ArrayTube® microarray detection. The fea......A proof of principle of a multi-target assay for genotyping Salmonella has been developed targeting 62 genomic marker sequences of Salmonella related to pathogenicity. The assay is based on multiplex ligation detection reaction (LDR) followed by customized ArrayTube® microarray detection...... of four serovars each serovar was characterized by a unique virulence associated gene repertoire. The LDR microarray platform proved to be a convenient, rapid and easy to use tool with potential in tracing a Salmonella contamination in the food chain, for outbreak studies, and to provide data for risk...

  4. Ultrasensitive monitoring of ribozyme cleavage product using molecular-beacon-ligation system

    Institute of Scientific and Technical Information of China (English)

    MENG XiangXian; TANG ZhiWen; WANG KeMin; TAN WeiHong; YANG XiaoHai; LI Jun; GUO QiuPing


    This paper reports a new approach to detect ribozyme cleavage product based on the molecular- beacon-ligation system. The molecular beacon, designed in such a way that one-half of its loop is complementary to ribozyme cleavage product, is used to monitor ligation process of RNA/DNA complex in a homogeneous solution and to convert directly cleavage product information into fluorescence signal. The method need not label ribozyme and ribozyme substrate, which is fast, simple and ultrasensitive for detection of cleavage product. Detection limit of the assay is 0.05 nmol/L. The cleavage product of hammerhead ribozyme against hepatitis C virus RNA (HCV-RNA) was detected perfectly based on this assay. Owing to its ultrasensitivity, excellent specificity, convenience and fidelity, this method might hold out great promise in ribozyme reaction and ribozyme gene therapy.

  5. Generation of an affinity column for antibody purification by intein-mediated protein ligation. (United States)

    Sun, Luo; Ghosh, Inca; Xu, Ming-Qun


    Coupling an antigenic peptide to a solid support is a crucial step in the affinity purification of a peptide-specific antibody. Conventional methods for generating reactive agarose, cellulose or other matrices for peptide conjugation are laborious and can result in a significant amount of chemical waste. In this report, we present a novel method for the facile production of a peptide affinity column by employing intein-mediated protein ligation (IPL) in conjunction with chitin affinity chromatography. A reactive thioester was generated at the C-terminal of the chitin binding domain (CBD) from the chitinase A1 of Bacillus circulans WL-2 by thiol-induced cleavage of the peptide bond between the CBD and a modified intein. Peptide epitopes possessing an N-terminal cysteine were ligated to the chitin bound CBD tag. We demonstrate that the resulting peptide columns permit the highly specific and efficient affinity purification of antibodies from animal sera.


    Energy Technology Data Exchange (ETDEWEB)

    Kimura, R; Camarero, J A


    The present paper reviews the use of expressed protein ligation for the biosynthesis of backbone cyclic polypeptides. This general method allows the in vivo and in vitro biosynthesis of cyclic polypeptides using recombinant DNA expression techniques. Biosynthetic access to backbone cyclic peptides opens the possibility to generate cell-based combinatorial libraries that can be screened inside living cells for their ability to attenuate or inhibit cellular processes.

  7. Are self-ligating brackets related to less formation of Streptococcus mutans colonies? A systematic review

    Directory of Open Access Journals (Sweden)

    Leonard Euler Andrade Gomes do Nascimento


    Full Text Available OBJECTIVE: To verify, by means of a systematic review, whether the design of brackets (conventional or self-ligating influences adhesion and formation of Streptococcus mutans colonies. METHODS: Search strategy: four databases (Cochrane Central Register of Controlled Trials, Ovid ALL EMB Reviews, PubMed and BIREME were selected to search relevant articles covering the period from January 1965 to December 2012. Selection Criteria: in first consensus by reading the title and abstract. The full text was obtained from publications that met the inclusion criteria. Data collection and analysis: Two reviewers independently extracted data using the keywords: conventional, self-ligating, biofilm, Streptococcus mutans, and systematic review; and independently evaluated the quality of the studies. In case of divergence, the technique of consensus was adopted. RESULTS: The search strategy resulted in 1,401 articles. The classification of scientific relevance revealed the high quality of the 6 eligible articles of which outcomes were not unanimous in reporting not only the influence of the design of the brackets (conventional or self-ligating over adhesion and formation of colonies of Streptococcus mutans, but also that other factors such as the quality of the bracket type, the level of individual oral hygiene, bonding and age may have greater influence. Statistical analysis was not feasible because of the heterogeneous methodological design. CONCLUSIONS: Within the limitations of this study, it was concluded that there is no evidence for a possible influence of the design of the brackets (conventional or self-ligating over colony formation and adhesion of Streptococcus mutans.

  8. An enhanced method for sequence walking and paralog mining: TOPO® Vector-Ligation PCR

    Directory of Open Access Journals (Sweden)

    Davis Thomas M


    Full Text Available Abstract Background Although technological advances allow for the economical acquisition of whole genome sequences, many organisms' genomes remain unsequenced, and fully sequenced genomes may contain gaps. Researchers reliant upon partial genomic or heterologous sequence information require methods for obtaining unknown sequences from loci of interest. Various PCR based techniques are available for sequence walking - i.e., the acquisition of unknown DNA sequence adjacent to known sequence. Many such methods require rigid, elaborate protocols and/or impose narrowly confined options in the choice of restriction enzymes for necessary genomic digests. We describe a new method, TOPO® Vector-Ligation PCR (or TVL-PCR that innovatively integrates available tools and familiar concepts to offer advantages as a means of both targeted sequence walking and paralog mining. Findings TVL-PCR exploits the ligation efficiency of the pCR®4-TOPO® (Invitrogen, Carlsbad, California vector system to capture fragments of unknown sequence by creating chimeric molecules containing defined priming sites at both ends. Initially, restriction enzyme-digested genomic DNA is end-repaired to create 3' adenosine overhangs and is then ligated to pCR4-TOPO vectors. The ligation product pool is used directly as a template for nested PCR, using specific primers to target orthologous sequences, or degenerate primers to enable capture of paralogous gene family members. We demonstrated the efficacy of this method by capturing entire coding and partial promoter sequences of several strawberry Superman-like genes. Conclusions TVL-PCR is a convenient and efficient method for DNA sequence walking and paralog mining that is applicable to any organism for which relevant DNA sequence is available as a basis for primer design.

  9. Superficial Dorsal Vein Injury/Thrombosis Presenting as False Penile Fracture Requiring Dorsal Venous Ligation


    Arash Rafiei, MD; Tariq S. Hakky, MD; Daniel Martinez, MD; Justin Parker, MD; Rafael Carrion, MD


    Introduction: Conditions mimicking penile fracture are extremely rare and have been seldom described. Aim: To describe a patient with false penile fracture who presented with superficial dorsal vein injury/thrombosis managed with ligation. Methods: A 33‐year‐old male presented with penile swelling and ecchymosis after intercourse. A penile ultrasound demonstrated a thrombosed superficial dorsal vein but also questionable fracture of the tunica albuginea. As the thrombus was expanding, h...

  10. Clinical and psychological repercussions of videolaparoscopic tubal ligation: observational, single cohort, retrospective study

    Directory of Open Access Journals (Sweden)

    Daniel Spadoto Dias

    Full Text Available CONTEXT AND OBJECTIVE: Tubal ligation is one of the most commonly used contraceptive methods worldwide. Since the controversy over the potential effects of tubal sterilization still continues, this study aimed to evaluate the clinical and psychological repercussions of videolaparoscopic tubal ligation.DESIGN AND SETTING: Observational, single cohort, retrospective study, conducted in a tertiary public hospital.METHODS: A questionnaire was applied to 130 women aged 21-46 years who underwent videolaparoscopic tubal ligation by means of tubal ring insertion or bipolar electrocoagulation and sectioning, between January 1999 and December 2007. Menstrual cycle interval, intensity and duration of bleeding, premenstrual symptoms, dysmenorrhea, dyspareunia, noncyclic pelvic pain and degree of sexual satisfaction were assessed in this questionnaire. Each woman served as her own control, and comparisons were made between before and after the surgical procedure and between the two techniques used.RESULTS: The clinical and psychological repercussions were significant, with increases in bleeding (P = 0.001, premenstrual symptoms (P < 0.001, dysmenorrhea (P = 0.019 and noncyclic pelvic pain (P = 0.001; and reductions in the number of sexual intercourse occurrences per week (P = 0.001 and in libido (P = 0.001. Women aged ≤ 35 years at the time of sterilization were more likely to develop menstrual abnormalities. The bipolar electrocoagulation method showed greater clinical and psychological repercussions.CONCLUSION: Regardless of the technique used, videolaparoscopic tubal ligation had repercussions consisting of increased menstrual flow and premenstrual symptoms, especially in women aged ≤ 35 years, and also had a negative influence on sexual activity.

  11. Banding ligation versus beta-blockers for primary prevention in oesophageal varices in adults

    DEFF Research Database (Denmark)

    Gluud, Lise Lotte; Krag, Aleksander


    Non-selective beta-blockers are used as a first-line treatment for primary prevention in patients with medium- to high-risk oesophageal varices. The effect of non-selective beta-blockers on mortality is debated and many patients experience adverse events. Trials on banding ligation versus non......-selective beta-blockers for patients with oesophageal varices and no history of bleeding have reached equivocal results....

  12. Serum markers of the extracellular matrix remodeling reflect antifibrotic therapy in bile-duct ligated rats


    Robert eSchierwagen; Sabine eKlein; Diana Julie Leeming; Michaela eGranzow; Mette Juul Nielsen; Tilman eSauerbruch; Aleksander eKrag; Morten A Karlsdal; Jonel eTrebicka


    BackgroundProgression of liver fibrosis is characterized by synthesis and degradation of extracellular matrix (ECM). Matrix-metalloproteinases (MMP) cleave collagen fibers at a specific site and thereby generate soluble fragments of ECM (neo-epitopes). The levels of these neo-epitopes might reflect the stage of liver fibrosis and may allow monitoring of anti-fibrotic therapies. Here we analyzed these neo-epitopes as read-out for a liver directed therapy with statins.MethodsBile duct ligation ...

  13. Venous Ligation: A Novel Strategy for Glans Enhancement in Penile Prosthesis Implantation


    Geng-Long Hsu; Hill, James W.; Cheng-Hsing Hsieh; Shih-Ping Liu; Chih-Yuan Hsu


    Although penile implantation remains a final solution for patients with refractory impotence, undesirable postoperative effects, including penile size reduction and cold sensation of the glans penis, remain problematic. We report results of a surgical method designed to avoid these problems. From 2003 to 2013, 35 consecutive patients received a malleable penile implant. Of these, 15 men (the enhancing group) were also treated with venous ligation of the retrocoronal venous plexus, deep dorsal...

  14. Transversal changes in dental arches from non-extraction treatment with self ligating brackets


    Liliana Avila Maltagliati; Yasushi Inoue Myiahira; Liana Fattori; Leopoldino Capelozza Filho; Mauricio Cardoso


    OBJECTIVE: The present study aimed at analyzing, with the use of dental casts, the transverse changes of the upper and lower dental arches, after non-extraction orthodontic treatment, with self-ligating brackets. METHODS: The sample comprised 29 patients, all presenting Class I malocclusion with upper and lower crowding of at least 4 mm and treated only with a fixed appliance, without stripping, extraction or distalization. The dental casts were obtained before and after leveling with 0.019 x...

  15. Producing peptide arrays for epitope mapping by intein-mediated protein ligation. (United States)

    Sun, Luo; Rush, John; Ghosh, Inca; Maunus, Jeremy R; Xu, Ming-Qun


    Peptide arrays are increasingly used to define antibody epitopes and substrate specificities of protein kinases. Their use is hampered, however, by ineffective and variable binding efficiency of peptides, which often results in low sensitivity and inconsistent results. To overcome these limitations, we have developed a novel method for making arrays of synthetic peptides on various membranes after ligating the peptide substrates to an intein-generated carrier protein. We have conducted screening for optimal carrier proteins by immunoreactivity and direct assessment of binding using a peptide derivatized at a lysine sidechain with fluorescein, CDPEK(fluorescein)DS. Ligation of a synthetic peptide antigen to a carrier protein, HhaI methylase, resulted in an improved retention of peptides and an increased sensitivity of up to 10(4)-fold in immunoassay- and epitope-scanning experiments. Denaturing the ligation products with 2% sodium dodecyl sulfate (SDS) or an organic solvent (20% methanol) prior to arraying did not significantly affect the immunoreactivity of the HhaI methylase-peptide product. Because the carrier protein dominates the binding of ligation products and contains one peptide reactive site, the amount of peptide arrayed onto the membranes can be effectively normalized. This technique was utilized in the alanine scanning of hemagglutinin (HA) antigen using two monoclonal antibodies, resulting in distinguishing the different antigen epitope profiles. Furthermore, we show that this method can be used to characterize the antibodies that recognize phosphorylated peptides. This novel approach allows for synthetic peptides to be uniformly arrayed onto membranes, compatible with a variety of applications.

  16. Diamino-ligated platinum(II) and platinum(IV) phenoxide complexes; syntheses and crystal structures

    NARCIS (Netherlands)

    Koten, G. van; Kapteijn, G.M.; Meijer, M.D.; Grove, D.M.; Veldman, N.; Spek, A.L.


    The reaction of the diamino-ligated dimethylplatinum(II) complex [Pt(Me){2}(bpy)] (bpy=2, 2'-bipyridyl) with phenol affords the new complex [Pt(Me)(OPh)(bpy)] (1). The X-ray crystal structure of square-planar 1 is reported: orthorhombic, space group P2{1}2{1}2{1} (No. 19), a = 9.1625(12), b = 12.392

  17. Molecular identification of Clonorchis sinensis and discrimination with other opisthorchid liver fluke species using multiple Ligation-depended Probe Amplification (MLPA

    Directory of Open Access Journals (Sweden)

    Liang Chi


    Full Text Available Abstract Background Infections with the opisthorchid liver flukes Clonorchis sinensis, Opisthorchis viverrini, and O. felineus cause severe health problems globally, particularly in Southeast Asia. Early identification of the infection is essential to provide timely and appropriate chemotherapy to patients. Results In this study we evaluate a PCR-based molecular identification method, Multiplex Ligation-dependent Probe Amplification (MLPA, which allows rapid and specific detection of single nucleotide acid differences between Clonorchis sinensis, Opisthorchis viverrini and O. felineus. Three probe pairs were derived from the Internally Transcribed Spacer 1 (ITS1 of three opisthorchid liver flukes using a systematic phylogenetic analysis. Specific loci were detected in all three species, yielding three amplicons with 198,172 and 152 bp, respectively, while no cross reactions were observed. A panel of 66 C. sinensis isolates was screened using MLPA. All species were positively identified, and no inhibition was observed. The detection limit was 103 copies of the ITS gene for the three liver flukes, or about 60 pg genomic DNA for Clonorchis sinensis. Amplification products can be detected by electrophoresis on agarose gel or in a capillary sequencer. In addition, genomic DNA of Clonorchis sinensis in fecal samples of infected rats was positively amplified by MLPA. Conclusion The flexibility and specificity make MLPA a potential tool for specific identification of infections by opisthorchid liver flukes in endemic areas.

  18. Enhanced propagation of photon density waves in random amplifying media

    CERN Document Server

    Renthlei, Lalruatfela; Ramakrishna, S A


    We demonstrate enhanced wave-like character of diffuse photon density waves (DPDW) in an amplifying random medium. The amplifying nature makes it contingent to choose the wave solution that grows inside the amplifying medium, and has a propagation vector pointing opposite to the growth direction. This results in negative refraction of the DPDW at an absorbing-amplifying random medium interface as well as the possibility of supporting "anti"-surface-like modes at the interface. A slab of amplifying random medium sandwiched between two absorbing random media supports waveguide resonances that can be utilized to extend the imaging capabilities of DPDW.

  19. Enhanced propagation of photon density waves in random amplifying media (United States)

    Renthlei, Lalruatfela; Wanare, Harshawardhan; Ramakrishna, S. Anantha


    We demonstrate enhanced wavelike character of diffuse photon density waves (DPDW) in an amplifying random medium. The amplifying nature makes it necessary to choose the wave solution that grows inside the amplifying medium, and has a propagation vector pointing opposite to the growth direction. This results in negative refraction of the DPDW at an absorbing-amplifying random medium interface as well as the possibility of supporting "anti"-surface-like modes at the interface. A slab of an amplifying random medium sandwiched between two absorbing random media supports waveguide resonances that can be utilized to extend the imaging capabilities of DPDW.

  20. Entropy score, patent ductus arteriosus (PDA), and cardiopulmonary bypass (CPB): ligation of PDA on CPB can compromise cerebral blood flow. (United States)

    Neema, Praveen Kumar; Dharan, Baiju S; Singha, Subrata Kumar; Sethuraman, Manikandan; Rathod, Ramesh Chandra


    A patent ductus arteriosus (PDA) is often present in patients undergoing correction of congenital heart disease. It is well appreciated that during cardiopulmonary bypass (CPB), a PDA steals arterial inflow into pulmonary circulation, and may lead to systemic hypoperfusion, excessive pulmonary blood flow (PBF) and distention of the left heart. Therefore, PDA is preferably ligated before initiation of CPB. We describe acute decreases of arterial blood pressure and entropy score with the initiation of CPB and immediate increase in entropy score following the PDA ligation in a child undergoing intracardiac repair of ventricular septal defect and right ventricular infundibular stenosis. The observation strongly indicates that a PDA steals arterial inflow into pulmonary circulation and if the PDA is dissected and ligated on CPB or its ligation on CPB is delayed the cerebral perfusion is potentially compromised.

  1. Self-ligating versus Invisalign: analysis of dento-alveolar effects (United States)

    Pavoni, Chiara; Lione, Roberta; Laganà, Giuseppina; Cozza, Paola


    Summary Aim The aim of this study was to evaluate the changes in the transverse dimension and the perimeter of the maxillary arch produced by low friction self-ligating brackets TIME 3 compared to the Invisalign technique. Materials and methods Both the self-ligating sample and the Invisalign group were composed of 20 subjects, evaluated at the beginning (T0) and at the completion of therapy (T1). All subjects presented a Class I malocclusion with mild crowding in a permanent dentition, without craniofacial anomalies, missing teeth or a history of orthodontic treatment. Dento-alveolar measurements were made on the maxillary dental casts at T0 and T1. Significant differences between the treated groups were assessed with Independent Samples t test (pInvisalign group were recorded for CWC, FPWF, FPWL, SPWF, SPWL, and AP measurements. No significant changes were found for CWL, MWF, MWL, and AD values. There was not a statistically significant difference between the treatment durations of the groups: 1.8 years for both patients. These data suggest that Invisalign treatment cannot be somewhat faster than fixed appliances. Moreover the final occlusion might not be as ideal. Conclusions The low fiction self-ligating system produced statistically significant different outcomes in the transverse dento-alveolar width and the perimeter of the maxillary arch during treatment when compared to Invisalign tecnique. PMID:22238719

  2. DNA strand transfer catalyzed by vaccinia topoisomerase: ligation of DNAs containing a 3' mononucleotide overhang. (United States)

    Cheng, C; Shuman, S


    The specificity of vaccinia topoisomerase for transesterification to DNA at the sequence 5'-CCCTT and its versatility in strand transfer have illuminated the recombinogenic properties of type IB topoisomerases and spawned topoisomerase-based strategies for DNA cloning. Here we characterize a pathway of topoisomerase-mediated DNA ligation in which enzyme bound covalently to a CCCTT end with an unpaired +1T nucleotide rapidly and efficiently joins the CCCTT strand to a duplex DNA containing a 3' A overhang. The joining reaction occurs with high efficiency, albeit slowly, to duplex DNAs containing 3' G, T or C overhangs. Strand transfer can be restricted to the correctly paired 3' A overhang by including 0.5 M NaCl in the ligation reaction mixture. The effects of base mismatches and increased ionic strength on the rates of 3' overhang ligation provide a quantitative picture of the relative contributions of +1 T:A base pairing and electrostatic interactions downstream of the scissile phosphate to the productive binding of an unlinked acceptor DNA to the active site. The results clarify the biochemistry underlying topoisomerase-cloning of PCR products with non-templated 3' overhangs.

  3. External root resorption with the self-ligating Damon system—a retrospective study

    Directory of Open Access Journals (Sweden)

    Roberta Heiffig Handem


    Full Text Available Abstract Background The aim of this study was to compare the degree of external apical root resorption (EARR in patients treated with self-ligating Damon appliances and with conventional preadjusted appliances. Methods The sample comprised 52 patients, divided into two groups. Group 1 consisted of 25 patients treated with self-ligating Damon appliances, with an initial age of 16.04 years, final age of 18.06 years, and treatment time of 2.02 years. Group 2 consisted of 27 patients, treated with conventional preadjusted appliances, with an initial age of 16.77 years, final age of 18.47 years and treatment time of 1.70 years. The groups were matched regarding the initial and final ages, treatment time, type of malocclusion, and treatment protocol without extractions. Root resorption was evaluated on periapical radiographs of the maxillary and mandibular incisors at the end of orthodontic treatment with the scores of Levander and Malmgren. Intergroup comparisons of root resorption were performed with Mann-Whitney tests. Results No significant difference in the degree of root resorption between the two groups was found. Conclusions Similar degrees of resorption can be expected after non-extraction treatment with Damon self-ligating or conventional preadjusted appliances.

  4. Experiments to optimize enzyme substitution therapy in pancreatic duct-ligated pigs. (United States)

    Kammlott, E; Karthoff, J; Stemme, K; Gregory, P; Kamphues, J


    Ligation of the pancreatic duct in pigs leads to severe maldigestion and malabsorption of crude nutrients. Supplementation with 24 capsules of Creon (Solvay Pharmaceuticals GmbH, Hannover, Germany) per meal led to an increased digestibility of crude nutrients. With regard to optimization of the treatment of EPI no essential improvements can be achieved by adding omeprazol or lecithin to the diet. In pancreatic duct-ligated pigs the isolated addition of omeprazol led to an increase of the pre-caecal digestibility of crude fat and organic matter. With additional enzyme substitution, the application of omeprazol did not result in an improved fat digestibility. Isolated addition of lecithin to the diet resulted in a reduced total digestibility of crude fat. Offering the diet twice a day and using a higher frequency of enzyme applications (four or six instead of only two applications) had no effects on the digestibilty of crude fat or organic matter. According to the observations in pancreatic duct-ligated pigs, the addition of missing enzymes to the diet led to the best treatment results in EPI. Administration of omeprazol or a higher feeding frequency as well as the application of enzymes in small proportion of the whole meal or dosages given consecutively over the day showed no advantages. Furthermore, the present study suggests that the addition of lecithin cannot be recommended in EPI, when given diets with butter as the predominant fat source as in human dietetics.

  5. Evaluation of force released by deflection of orthodontic wires in conventional and self-ligating brackets

    Directory of Open Access Journals (Sweden)

    Rodrigo Hitoshi Higa

    Full Text Available ABSTRACT Introduction: The aim of the study was to evaluate deflection forces of rectangular orthodontic wires in conventional (MorelliTM, active (In-Ovation RTM and passive (Damon 3MXTM self-ligating brackets. Material and Methods: Two brands of stainless steel and nickel-titanium (NiTi wires (MorelliTM and GACTM, in addition to OrmcoTM copper-nickel-titanium wires were used. Specimens were assembled in a clinical simulation device especially designed for this study and tested in an Instron universal testing machine. For the testing procedures, an acrylic structure representative of the maxillary right central incisor was lingually moved in activations of 0 to 1 mm, with readings of the force released by deflection in unloading of 0.5, 0.8 and 1 mm at a constant speed of 2 mm/min. Inter-bracket forces with stainless steel, NiTi and CuNiTi were individually compared by two-way ANOVA, followed by Tukey’s tests. Results: Results showed that there were lower forces in conventional brackets, followed by active and passive self-ligating brackets. Within the brands, only for NiTi wires, the MorelliTM brand presented higher forces than GACTM wires. Conclusions: Bracket systems provide different degrees of deflection force, with self-ligating brackets showing the highest forces.

  6. Antioxidant Effect of Sepia Ink Extract on Extrahepatic Cholestasis Induced by Bile Duct Ligation in Rats

    Institute of Scientific and Technical Information of China (English)

    Hanan Saleh; Amel M Soliman; Ayman S Mohamed; Mohamed-Assem S Marie


    Objective The aim of our study was to assess the complications of hepatic fibrosis associated with bile duct ligation and the potential curative role of sepia ink extract in hepatic damage induced by bile duct ligation. Methods Rattus norvegicus rats were divided into 3 groups: Sham-operated group, model rats that underwent common bile duct ligation (BDL), and BDL rats treated orally with sepia ink extract (200 mg/kg body weight) for 7, 14, and 28 d after BDL. Results There was a significant reduction in hepatic enzymes, ALP, GGT, bilirubin levels, and oxidative stress in the BDL group after treatment with sepia ink extract. Collagen deposition reduced after sepia ink extract treatment as compared to BDL groups, suggesting that the liver was repaired. Histopathological examination of liver treated with sepia ink extract showed moderate degeneration in the hepatic architecture and mild degeneration in hepatocytes as compared to BDL groups. Conclusion Sepia ink extract provides a curative effect and an antioxidant capacity on BDL rats and could ameliorate the complications of liver cholestasis.

  7. Safety and effectiveness of total splenic vessel ligations in paediatric patients with splenomegaly

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    Chen Zhen


    Full Text Available Backgrounds: Splenomegaly may contribute to hypersplenism and can result in thrombocytopenia. Many approaches are used to treat splenomegaly; however, the current management of splenomegaly has intrinsic limitations or disadvantages. Now, we initiate a new approach, that of total splenic vessel (artery and vein ligations (TSVLs in paediatric patients with splenomegaly. The purpose of our study is to evaluate the results obtained with TVSLs procedure for paediatric patients. Patients and Methods: Seventeen paediatric patients with splenomegaly were screened for enrolment into this retrospective analysis. Procedure: We identified and dissociated the splenic vessel. Next, we ligated the splenic artery and we used clips to ligate the vein distally and proximally. Result: The mean [standard deviation (SD] splenic infarction rate of a total of 17 patients was 77.5 (5.1% in 6 months after operation. After TSVL, the mean count of platelet (PLT and white blood cell (WBC increased significantly and reached a steady state in the third month. Both the PLT and WBC had a significance higher than pre-TSVL in a 1-year follow-up. Conclusion: Based on the evidence, we make cautious conclusions that TSVLs are a safe and effective method in the treatment of paediatric patients with splenomegaly, achieving a satisfactory long-term haematological response and benefit.

  8. The exonuclease activity of DNA polymerase γ is required for ligation during mitochondrial DNA replication (United States)

    Macao, Bertil; Uhler, Jay P.; Siibak, Triinu; Zhu, Xuefeng; Shi, Yonghong; Sheng, Wenwen; Olsson, Monica; Stewart, James B.; Gustafsson, Claes M.; Falkenberg, Maria


    Mitochondrial DNA (mtDNA) polymerase γ (POLγ) harbours a 3′–5′ exonuclease proofreading activity. Here we demonstrate that this activity is required for the creation of ligatable ends during mtDNA replication. Exonuclease-deficient POLγ fails to pause on reaching a downstream 5′-end. Instead, the enzyme continues to polymerize into double-stranded DNA, creating an unligatable 5′-flap. Disease-associated mutations can both increase and decrease exonuclease activity and consequently impair DNA ligation. In mice, inactivation of the exonuclease activity causes an increase in mtDNA mutations and premature ageing phenotypes. These mutator mice also contain high levels of truncated, linear fragments of mtDNA. We demonstrate that the formation of these fragments is due to impaired ligation, causing nicks near the origin of heavy-strand DNA replication. In the subsequent round of replication, the nicks lead to double-strand breaks and linear fragment formation. PMID:26095671

  9. Evaluation of force released by deflection of orthodontic wires in conventional and self-ligating brackets (United States)

    Higa, Rodrigo Hitoshi; Semenara, Nayara Thiago; Henriques, José Fernando Castanha; Janson, Guilherme; Sathler, Renata; Fernandes, Thais Maria Freire


    ABSTRACT Introduction: The aim of the study was to evaluate deflection forces of rectangular orthodontic wires in conventional (MorelliTM), active (In-Ovation RTM) and passive (Damon 3MXTM) self-ligating brackets. Material and Methods: Two brands of stainless steel and nickel-titanium (NiTi) wires (MorelliTM and GACTM), in addition to OrmcoTM copper-nickel-titanium wires were used. Specimens were assembled in a clinical simulation device especially designed for this study and tested in an Instron universal testing machine. For the testing procedures, an acrylic structure representative of the maxillary right central incisor was lingually moved in activations of 0 to 1 mm, with readings of the force released by deflection in unloading of 0.5, 0.8 and 1 mm at a constant speed of 2 mm/min. Inter-bracket forces with stainless steel, NiTi and CuNiTi were individually compared by two-way ANOVA, followed by Tukey’s tests. Results: Results showed that there were lower forces in conventional brackets, followed by active and passive self-ligating brackets. Within the brands, only for NiTi wires, the MorelliTM brand presented higher forces than GACTM wires. Conclusions: Bracket systems provide different degrees of deflection force, with self-ligating brackets showing the highest forces. PMID:28125144

  10. Synthesizing and modifying peptides for chemoselective ligation and assembly into quantum dot-peptide bioconjugates. (United States)

    Algar, W Russ; Blanco-Canosa, Juan B; Manthe, Rachel L; Susumu, Kimihiro; Stewart, Michael H; Dawson, Philip E; Medintz, Igor L


    Quantum dots (QDs) are well-established as photoluminescent nanoparticle probes for in vitro or in vivo imaging, sensing, and even drug delivery. A critical component of this research is the need to reliably conjugate peptides, proteins, oligonucleotides, and other biomolecules to QDs in a controlled manner. In this chapter, we describe the conjugation of peptides to CdSe/ZnS QDs using a combination of polyhistidine self-assembly and hydrazone ligation. The former is a high-affinity interaction with the inorganic surface of the QD; the latter is a highly efficient and chemoselective reaction that occurs between 4-formylbenzoyl (4FB) and 2-hydrazinonicotinoyl (HYNIC) moieties. Two methods are presented for modifying peptides with these functional groups: (1) solid phase peptide synthesis; and (2) solution phase modification of pre-synthesized, commercial peptides. We further describe the aniline-catalyzed ligation of 4FB- and HYNIC-modified peptides, in the presence of a fluorescent label on the latter peptide, as well as subsequent assembly of the ligated peptide to water-soluble QDs. Many technical elements of these protocols can be extended to labeling peptides with other small molecule reagents. Overall, the bioconjugate chemistry is robust, selective, and modular, thereby potentiating the controlled conjugation of QDs with a diverse array of biomolecules for various applications.

  11. Real-Time NMR Studies of Oxyamine Ligations of Reducing Carbohydrates under Equilibrium Conditions. (United States)

    Baudendistel, Oliver R; Wieland, Daniel E; Schmidt, Magnus S; Wittmann, Valentin


    Ligation reactions at the anomeric center of carbohydrates have gained increasing importance in the field of glycobiology. Oxyamines are frequently used in labeling, immobilization, and bioconjugation of reducing carbohydrates. Herein, we present a systematic investigation of these ligation reactions under aqueous conditions. A series of four unprotected monosaccharides (glucose, N-acetylglucosamine, mannose, and 2-deoxyglucose) and one disaccharide (N,N'-diacetylchitobiose) was reacted with three primary and one secondary oxyamine. We monitored the concentrations of the starting materials and products by (1) H NMR spectroscopy and determined reaction times and equilibrium yields. Our experiments show that the outcome of the ligation reaction is not only dependent on the sugar and oxyamine used but also strongly on the reaction conditions. In the case of glucose, lowering the pH from 6 to 3 led to steadily increasing reaction rates, whereas the yields were decreasing at the same time. Variation of the temperature did not only influence the product ratio in equilibrium but can also have a strong impact on the equilibrium yield. In the case of reactions of a primary oxyamine, increased temperatures led to a higher proportion of acyclic products. Reaction of the secondary oxyamine with glucose unexpectedly led to lower yields at higher temperatures.

  12. Lipid Raft is required for PSGL-1 ligation induced HL-60 cell adhesion on ICAM-1.

    Directory of Open Access Journals (Sweden)

    Tingshuang Xu

    Full Text Available P-selectin glycoprotein ligand-1 (PSGL-1 and integrins are adhesion molecules that play critical roles in host defense and innate immunity. PSGL-1 mediates leukocyte rolling and primes leukocytes for integrin-mediated adhesion. However, the mechanism that PSGL-1 as a rolling receptor in regulating integrin activation has not been well characterized. Here, we investigate the function of lipid raft in regulating PSGL-1 induced β2 integrin-mediated HL-60 cells adhesion. PSGL-1 ligation with antibody enhances the β2 integrin activation and β2 integrin-dependent adhesion to ICAM-1. Importantly, with the treatment of methyl-β-cyclodextrin (MβCD, we confirm the role of lipid raft in regulating the activation of β2 integrin. Furthermore, we find that the protein level of PSGL-1 decreased in raft fractions in MβCD treated cells. PSGL-1 ligation induces the recruitment of spleen tyrosine kinase (Syk, a tyrosine kinase and Vav1 (the pivotal downstream effector of Syk signaling pathway involved in cytoskeleton regulation to lipid raft. Inhibition of Syk activity with pharmacologic inhibitor strongly reduces HL-60 cells adhesion, implicating Syk is crucial for PSGL-1 mediated β2 integrin activation. Taken together, we report that ligation of PSGL-1 on HL-60 cells activates β2 integrin, for which lipid raft integrity and Syk activation are responsible. These findings have shed new light on the mechanisms that connect leukocyte initial rolling with subsequent adhesion.

  13. Arterial Ligation for Infected Femoral Psuedo-Aneurysm in Drug Injecting Abusers

    Directory of Open Access Journals (Sweden)

    Mohammadzade Mohammad Ali


    Full Text Available Pseudo-aneurysm of the femoral artery is the most common arterial complication in drug injecting abusers. Scholars in vascular surgery have published debating statements regarding techniques of successful surgical management during last two decades. We present the results of simple arterial ligation in a series of 32 patients presenting with infected femoral pseudo-aneurysm. Most of the patients were males (89%. Young persons in the age group of 15-44 years were mostly affected. Site of lesion included common femoral artery in 65% , superficial femoral artery 28% and at bifurcation 6.2%. celulitis in 14 (53%, abscess & "ncelulitis in 6 (19%, necrosing fasciitis in 2 (6.2% and vascular abscess in 7 (22% cases were the forms of associated local infection. There was no hemorrhage, vascular thrombosis, amputation, or mortality. Claudicating were the only complications identified in 2 patients with Tripe ligation. Ligation is the optimal management for infected pseudo-aneurysms because it is easy, cost-effective, and safe. Early reconstruction is not recommended, since there is an extended infection in the location of the pseudo-aneurysm.

  14. Comparison of Ligation-Mediated PCR Methods in Differentiation of Mycobacterium tuberculosis Strains

    Directory of Open Access Journals (Sweden)

    Anna Zaczek


    Full Text Available Fast and inexpensive identification of epidemiological links between limited number of Mycobacterium tuberculosis strains is required to initially evaluate hospital outbreaks, laboratory crosscontaminations, and family or small community transmissions. The ligation-mediated PCR methods (LM-PCR appear sufficiently discriminative and reproducible to be considered as a good candidate for such initial, epidemiological analysis. Here, we compared the discriminative power of the recently developed in our laboratory fast ligation amplification polymorphism (FLAP method with fast ligation-mediated PCR (FLiP. Verification of the results was based on analyzing a set of reference strains and RFLP-IS6110 typing. The HGDI value was very similar for both LM-PCR methods and RFLP-IS6110 typing. However, only 52% of strains were correspondingly grouped by both FLiP and FLAP methods. Differentiation by FLAP method demonstrated a limited similarity to IS6110-RFLP (37,7%. As much as 78,7% of strains were grouped identically when differentiated by FLiP and IS6110-RFLP methods. The analysis differentiated 31, 35, and 36 groups when using FLAP, FLiP, and RFLP-IS6110 methods, respectively.

  15. Time amplifying techniques towards atomic time resolution

    Institute of Scientific and Technical Information of China (English)

    LI JingZhen


    High speed imaging technology has opened applications in many fields,such as collision,detonating,high voltage discharge,disintegration and transfer of phonon and exciton in solid,photosynthesis primitive reaction,and electron dynamics inside atom shell.In principle,all of the transient processes need to be explained theoretically and,st the same time,the time amplifying technique is required for observations of these processes.The present review concerns the atomic time amplifying mechanism of optical information and the extremely-high speed imaging methods,which are expressed in terms of the short time amplifying techniques.It is well-known that for extremely-high speed imaging with the converter tube,the temporal resolution is in the order of sub-picosecond of the streak imaging,and the imaging frequency is 6×10~8-5×10~9 fps(frame per second)of the frame imaging.On the other hand,for the tubeless extremely-high speed imaging,the imaging frequency is 10~7-10~(14) fps,and its mechanism of forming high speed and framing could involve a lot of factors of the light under investigation,for instance,light speed,light parallelism,the parameters of light wave such as amplitude,phase,polarization and wavelength,and even quantum properties of photon.In the cascaded system of electromagnetic wave and particle wave,it is possible to simultaneously realize extremely-high resolution in time and space,which is higher than a kite resolution.Then it would be possible to break the limit of the Heisenberg uncertainty relation of the optical frequency band.

  16. Time amplifying techniques towards atomic time resolution

    Institute of Scientific and Technical Information of China (English)


    High speed imaging technology has opened applications in many fields,such as collision,detonating, high voltage discharge,disintegration and transfer of phonon and exciton in solid,photosynthesis primitive reaction,and electron dynamics inside atom shell.In principle,all of the transient processes need to be explained theoretically and,at the same time,the time amplifying technique is required for observations of these processes.The present review concerns the atomic time amplifying mechanism of optical information and the extremely-high speed imaging methods,which are expressed in terms of the short time amplifying techniques.It is well-known that for extremely-high speed imaging with the converter tube,the temporal resolution is in the order of sub-picosecond of the streak imaging,and the imaging frequency is 6×10 8 ―5×10 9 fps(frame per second)of the frame imaging.On the other hand,for the tubeless extremely-high speed imaging,the imaging frequency is 10 7 ―10 14 fps,and its mechanism of forming high speed and framing could involve a lot of factors of the light under investigation,for instance,light speed,light parallelism,the parameters of light wave such as amplitude,phase,polari- zation and wavelength,and even quantum properties of photon.In the cascaded system of electro- magnetic wave and particle wave,it is possible to simultaneously realize extremely-high resolution in time and space,which is higher than a kite resolution.Then it would be possible to break the limit of the Heisenberg uncertainty relation of the optical frequency band.

  17. Investigations of electronic amplifiers supplying a piezobimorph actuator (United States)

    Milecki, Andrzej; Regulski, Roman


    Piezoelectric bending actuators, also known as bimorphs, are characterized by very good dynamic properties and by displacements in a range of a few millimeters. Therefore these actuators are used in a wide range of applications. However their usage is limited because they require supplying amplifiers with output voltage of about 200 V, which are rather expensive. This paper presents investigation results of such amplifiers with high voltage output. The model of a piezobending actuator is proposed and implemented in Matlab-Simulink software in order to simulate the behavior of the actuator supplied by the amplifiers. The simulation results are presented and compared with investigation results of high voltage amplifier used for supplying a piezoactuator. The influence of current limitation of operational amplifier on the actuator current is tested. Finally, a low cost audio power amplifier is proposed to control the piezobender actuator (as a cheaper alternative to the high-voltage amplifier) and its investigations results are presented in the paper.

  18. Low power RF amplifier circuit for ion trap applications (United States)

    Noriega, J. R.; García-Delgado, L. A.; Gómez-Fuentes, R.; García-Juárez, A.


    A low power RF amplifier circuit for ion trap applications is presented and described. The amplifier is based on a class-D half-bridge amplifier with a voltage mirror driver. The RF amplifier is composed of an RF class-D amplifier, an envelope modulator to ramp up the RF voltage during the ion analysis stage, a detector or amplitude demodulation circuit for sensing the output signal amplitude, and a feedback amplifier that linearizes the steady state output of the amplifier. The RF frequency is set by a crystal oscillator and the series resonant circuit is tuned to the oscillator frequency. The resonant circuit components have been chosen, in this case, to operate at 1 MHz. In testings, the class-D stage operated at a maximum of 78 mW at 1.1356 MHz producing 225 V peak.

  19. Gain flattened distributed fiber raman amplifiers

    Institute of Scientific and Technical Information of China (English)


    An S band and a C band distributed fiber Raman amplifiers (DFRAs) with flattened gain and compensated dispersion have been studied and implemented with 1 427 nm and 1 455 nm mono-wavelength fiber Raman lasers as the pumped sources respectively. The gain of single-wave pumped S band and C band can reach 10 dB and 15 dB respectively. And a 50 nm gain flattened width was successfully obtained by using a chirp fiber Bragg grating (CFBG) gain flattened filter with gain ripple of 0.6 dB. The C band DFRA has been applied to CDMA wireless communication system successfully.

  20. Feedback analysis of transimpedance operational amplifier circuits


    Bruun, Erik


    The transimpedance or current feedback operational amplifier (CFB op-amp) is reviewed and compared to a conventional voltage mode op-amp using an analysis emphasizing the basic feedback characteristics of the circuit. With this approach the paradox of the constant bandwidth obtained from CFB op-amps is explained. It is demonstrated in a simple manner that the constant gain-bandwidth product of the conventional op-amp and the constant bandwidth of the CFB op-amp are both in accordance with bas...

  1. Universal strategies for the DNA-encoding of libraries of small molecules using the chemical ligation of oligonucleotide tags. (United States)

    Litovchick, Alexander; Clark, Matthew A; Keefe, Anthony D


    The affinity-mediated selection of large libraries of DNA-encoded small molecules is increasingly being used to initiate drug discovery programs. We present universal methods for the encoding of such libraries using the chemical ligation of oligonucleotides. These methods may be used to record the chemical history of individual library members during combinatorial synthesis processes. We demonstrate three different chemical ligation methods as examples of information recording processes (writing) for such libraries and two different cDNA-generation methods as examples of information retrieval processes (reading) from such libraries. The example writing methods include uncatalyzed and Cu(I)-catalyzed alkyne-azide cycloadditions and a novel photochemical thymidine-psoralen cycloaddition. The first reading method "relay primer-dependent bypass" utilizes a relay primer that hybridizes across a chemical ligation junction embedded in a fixed-sequence and is extended at its 3'-terminus prior to ligation to adjacent oligonucleotides. The second reading method "repeat-dependent bypass" utilizes chemical ligation junctions that are flanked by repeated sequences. The upstream repeat is copied prior to a rearrangement event during which the 3'-terminus of the cDNA hybridizes to the downstream repeat and polymerization continues. In principle these reading methods may be used with any ligation chemistry and offer universal strategies for the encoding (writing) and interpretation (reading) of DNA-encoded chemical libraries.

  2. Design criteria for ultrafast optical parametric amplifiers (United States)

    Manzoni, C.; Cerullo, G.


    Optical parametric amplifiers (OPAs) exploit second-order nonlinearity to transfer energy from a fixed frequency pump pulse to a variable frequency signal pulse, and represent an easy way of tuning over a broad range the frequency of an otherwise fixed femtosecond laser system. OPAs can also act as broadband amplifiers, transferring energy from a narrowband pump to a broadband signal and thus considerably shortening the duration of the pump pulse. Due to these unique properties, OPAs are nowadays ubiquitous in ultrafast laser laboratories, and are employed by many users, such as solid state physicists, atomic/molecular physicists, chemists and biologists, who are not experts in ultrafast optics. This tutorial paper aims at providing the non-specialist reader with a self-consistent guide to the physical foundations of OPAs, deriving the main equations describing their performance and discussing how they can be used to understand their most important working parameters (frequency tunability, bandwidth, pulse energy/repetition rate scalability, control over the carrier-envelope phase of the generated pulses). Based on this analysis, we derive practical design criteria for OPAs, showing how their performance depends on the type of the nonlinear interaction (crystal type, phase-matching configuration, crystal length), on the characteristics of the pump pulse (frequency, duration, energy, repetition rate) and on the OPA architecture.

  3. Hot prospect for new gene amplifier

    Energy Technology Data Exchange (ETDEWEB)


    Molecular biologist Francis Barany is investigating one of the hottest areas in biotechnology: a gene-amplification technique called ligase chain reaction, or LCR. Already scientists have used LCR to detect the tiny mutation that causes sickle cell anemia and have adapted it to screen for a handful of other genetic diseases simultaneously - in a single test-tube. Some experts, in fact, are predicting that LCR will supplement the polymerase chain reaction (PCR), and in some cases even supplant it. LCR could revolutionize DNA diagnostics just as PCR transformed basic molecular biology following its introduction 6 years ago. With its ease of automation and ability to produce useful quantitative results, LCR could become a major player in the rapidly growing market for DNA diagnostics. LCR, like PCR, uses snippets of nucleic acid, or oligonucleotides, that anneal to a specific, complementary sequence on the target DNA to be amplified. But where PCR uses oligos that bracket the stretch to be amplified, LCR uses pairs of oligos that completely cover the target sequence.

  4. Backward Raman Amplifier for Laser Wakefield Accelerator (United States)

    Ludwig, Joshua; Masson-Laborde, Paul-Edouard; Huller, Stefan; Rozmus, Wojciech; Wilks, Scott C.


    Particle in cell simulations via SCPIC and theoretical work on Raman amplification and laser wake field acceleration will be presented. Laser energy depletion has been shown to be a limiting factor during wake field acceleration. This work focuses on optimizing parameters for Raman amplification to work in conjunction with wake field acceleration in order in order to sustain an accelerating laser pulse as it generates plasma waves. It has been shown that laser pulses undergo red shifting during wake generation. Our work demonstrates that this red shifting results in a detuning between pump and seed in the backward Raman Amplifier. This detuning limits the amount of energy that can be transferred from the pump to the seed, and places new limits on backward Raman amplification. To overcome this limiting factor, this study makes use of a chirped pump allowing for extended coupling to the accelerating pulse. Three wave coupling model of Raman amplifier with a frequency shift term due to wake field will also be discussed and compared with PIC simulations.

  5. Amplified Fiber-Loop Ringdown Spectroscopy (United States)

    Litman, Jessica; Barnes, Jack; Loock, Hans-Peter


    Many commercial liquid chemical analysis systems, such as high-performance liquid chromatography (HPLC) or capillary electrophoresis consist of a separation followed by optical detection. Besides small volumes and low detection limits, the system should also allow the detection of a large variety of analytes. Existing absorption and fluorescence detectors are often not very sensitive or require labelling. Here, an absorption detector is presented based on cavity ring-down spectroscopy (CRDS) where the optical cavity is made from fibre optic waveguides and the light source is a continuous wave (cw) diode laser. The purpose of this project is to increase the detection of analytes through their overtone absorption in the telecom region at 1300 to 1500 nm. This is done by increasing the ratio of desired loss (extinction caused by the sample), to undesirable loss (due to the waveguides or solvents) through amplification of the ringdown signal using a gain-clamped erbium doped fibre amplifier (EDFA). The amplified cavity has a round-trip time of 750 ns and we achieved a detection limit of at most 250 ppm when measuring acetylene at 1532.83 nm. The application of our method to detection of dissolved analytes or particles in liquids will be discussed.

  6. Development of 3 kW at 325 MHz solid-state RF power amplifier using four power amplifier modules (United States)

    Ramarao, B. V.; Sonal, S.; Mishra, J. K.; Pande, M.; Singh, P.; Kumar, G.; Mukherjee, J.


    A high power solid-state RF power amplifier of 3 kW at 325 MHz has been developed using only four RF power amplifier modules of 850 W power output each. The design and characterization of RF power modules have been presented. A four way Wilkinson power combiner adds the output of four power amplifier modules with a total transmission loss of less than 6%. The combined power amplifier has a power gain of 20.2 dB at 1-dB compression point, and the corresponding output power is 2.8 kW at 325 MHz. The drain efficiency of the power amplifier is 65.3% at 3 kW. All the harmonics of this amplifier are below -40 dBc. The amplifier has better characteristics like fewer numbers of active devices per kilo watt, high efficiency, high gain, and ruggedness etc for RF accelerator applications.

  7. Power amplifiers in CMOS technology : a contribution to power amplifier theory and techniques

    NARCIS (Netherlands)

    Acar, Mustafa


    In order to meet the demands from the market on cheaper, miniaturized mobile communications devices realization of RF power amplifiers(PAs) in the mainstream CMOS technology is essential. In general, CMOS PAs require high supply-voltage to decrease the matching network losses and for high output pow

  8. Gender Differences on the Use of Amplifiers in Academic Writings

    Institute of Scientific and Technical Information of China (English)



      This study aims to investigate the use of amplifiers in term of gender and disciplinary groups in academic research arti⁃cles, which is based on the British Academic Written English Corpus (BAWE).18 amplifiers were examined across two dimen⁃sions:gender and disciplinary groups. The results show amplifiers are more common in males’ academic writings than in those of females in general, amplifiers are used more often in AH discipline. However, not all amplifiers show significant gender differ⁃ences between men and women. Six words show a significant difference between male and female writers:pretty, by far, perfect⁃ly, quite, a great deal, totally, which are used more often by males. However, the interesting is in LS discipline, most amplifiers are used more often by female than male writers and males tend to use by far more frequently than females.

  9. Multiple Differential-Amplifier MMICs Embedded in Waveguides (United States)

    Kangaslahti, Pekka; Schlecht, Erich


    Compact amplifier assemblies of a type now being developed for operation at frequencies of hundreds of gigahertz comprise multiple amplifier units in parallel arrangements to increase power and/or cascade arrangements to increase gains. Each amplifier unit is a monolithic microwave integrated circuit (MMIC) implementation of a pair of amplifiers in differential (in contradistinction to single-ended) configuration. Heretofore, in cascading amplifiers to increase gain, it has been common practice to interconnect the amplifiers by use of wires and/or thin films on substrates. This practice has not yielded satisfactory results at frequencies greater than 200 Hz, in each case, for either or both of two reasons: Wire bonds introduce large discontinuities. Because the interconnections are typically tens of wavelengths long, any impedance mismatches give rise to ripples in the gain-vs.-frequency response, which degrade the performance of the cascade.


    Institute of Scientific and Technical Information of China (English)

    Mashhour Mustafa; Bani Amer


    This paper deals with internally generated noise of bioelectric amplifiers that are usually used for processing of bioelectric events. The main purpose of this paper is to present a procedure for analysis of the effects of internal noise generated by the active circuits and to evaluate the output noise of the author's new designed bioelectric amplifier that caused by internal effects to the amplifier circuit itself in order to compare it with the noise generated by conventional amplifiers. The obtained analysis results of internally generated noise showed that the total output noise of bioelectric active circuits does not increase when some of their resistors have a larger value. This behavior is caused by the different transfer functions for the signal and the respective noise sources associated with these resistors. Moreover, the new designed bioelectric amplifier has an output noise less than that for conventional amplifiers. The obtained analysis results were also experimentally verified and the final conclusions were drawn.

  11. Increased Expression of TGF-β Signaling Components in a Mouse Model of Fibrosis Induced by Submandibular Gland Duct Ligation.

    Directory of Open Access Journals (Sweden)

    Lucas T Woods

    Full Text Available Transforming growth factor-β (TGF-β is a multi-functional cytokine with a well-described role in the regulation of tissue fibrosis and regeneration in the liver, kidney and lung. Submandibular gland (SMG duct ligation and subsequent deligation in rodents is a classical model for studying salivary gland damage and regeneration. While previous studies suggest that TGF-β may contribute to salivary gland fibrosis, the expression of TGF-β signaling components has not been investigated in relation to mouse SMG duct ligation-induced fibrosis and regeneration following ductal deligation. Following a 7 day SMG duct ligation, TGF-β1 and TGF-β3 were significantly upregulated in the SMG, as were TGF-β receptor 1 and downstream Smad family transcription factors in salivary acinar cells, but not in ductal cells. In acinar cells, duct ligation also led to upregulation of snail, a Smad-activated E-cadherin repressor and regulator of epithelial-mesenchymal transition, whereas in ductal cells upregulation of E-cadherin was observed while snail expression was unchanged. Upregulation of these TGF-β signaling components correlated with upregulation of fibrosis markers collagen 1 and fibronectin, responses that were inhibited by administration of the TGF-β receptor 1 inhibitors SB431542 or GW788388. After SMG regeneration following a 28 day duct deligation, TGF-β signaling components and epithelial-mesenchymal transition markers returned to levels similar to non-ligated controls. The results from this study indicate that increased TGF-β signaling contributes to duct ligation-induced changes in salivary epithelium that correlate with glandular fibrosis. Furthermore, the reversibility of enhanced TGF-β signaling in acinar cells of duct-ligated mouse SMG after deligation indicates that this is an ideal model for studying TGF-β signaling mechanisms in salivary epithelium as well as mechanisms of fibrosis initiation and their resolution.

  12. Low-noise amplifiers for satellite communications (United States)

    Whelehan, J.


    It is pointed out that over the past several years significant advances have been made in the overall capability of both microwave and mm-wave receivers. This is particularly apparent in the telecom market. Integral parts of advanced receiver technology are low-noise receivers. The advances currently being achieved in low-noise technology are partly based on developments in GaAs semiconductor technology. The development of high-cutoff-frequency beam lead mixer diodes has led to the development of mm-wave low-noise mixers with excellent low-noise capability. The advanced techniques are now being employed in field-deployable systems. Low noise is an important factor in satellite communications applications. Attention is given to C-band fixed satellite service, C-band parametric amplifiers, C-band FET, and X band, the Ku band, and the 30/20 GHz band.

  13. Current feedback operational amplifiers and their applications

    CERN Document Server

    Senani, Raj; Singh, A K; Singh, V K


    This book describes a variety of current feedback operational amplifier (CFOA) architectures and their applications in analog signal processing/generation. Coverage includes a comprehensive survey of commercially available, off-the-shelf integrated circuit CFOAs, as well as recent advances made on the design of CFOAs, including design innovations for bipolar and CMOS CFOAs.  This book serves as a single-source reference to the topic, as well as a catalog of over 200 application circuits which would be useful not only for students, educators and researchers in apprising them about the recent developments in the area but would also serve as a comprehensive repertoire of useful circuits for practicing engineers who might be interested in choosing an appropriate CFOA-based topology for use in a given application.

  14. Stochastic phenomena in a fiber Raman amplifier

    CERN Document Server

    Kalashnikov, Vladimir; Ania-Castanón, Juan Diego; Jacobsen, Gunnar; Popov, Sergei


    The interplay of such cornerstones of modern nonlinear fiber optics as a nonlinearity, stochasticity and polarization leads to variety of the noise induced instabilities including polarization attraction and escape phenomena harnessing of which is a key to unlocking the fiber optic systems specifications required in high resolution spectroscopy, metrology, biomedicine and telecommunications. Here, by using direct stochastic modeling, the mapping of interplay of the Raman scattering-based nonlinearity, the random birefringence of a fiber, and the pump-to-signal intensity noise transfer has been done in terms of the fiber Raman amplifier parameters, namely polarization mode dispersion, the relative intensity noise of the pump laser, fiber length, and the signal power. The obtained results reveal conditions for emergence of the random birefringence-induced resonance-like enhancement of the gain fluctuations (stochastic anti-resonance) accompanied by pulse broadening and rare events in the form of low power outpu...

  15. Gain Characteristics of Fiber Optical Parametric Amplifier

    Institute of Scientific and Technical Information of China (English)

    高明义; 姜淳; 胡卫生


    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.

  16. Modeling and design techniques for RF power amplifiers

    CERN Document Server

    Raghavan, Arvind; Laskar, Joy


    The book covers RF power amplifier design, from device and modeling considerations to advanced circuit design architectures and techniques. It focuses on recent developments and advanced topics in this area, including numerous practical designs to back the theoretical considerations. It presents the challenges in designing power amplifiers in silicon and helps the reader improve the efficiency of linear power amplifiers, and design more accurate compact device models, with faster extraction routines, to create cost effective and reliable circuits.

  17. InP Heterojunction Bipolar Transistor Amplifiers to 255 GHz (United States)

    Radisic, Vesna; Sawdai, Donald; Scott, Dennis; Deal, William; Dang, Linh; Li, Danny; Cavus, Abdullah; To, Richard; Lai, Richard


    Two single-stage InP heterojunction bipolar transistor (HBT) amplifiers operate at 184 and 255 GHz, using Northrop Grumman Corporation s InP HBT MMIC (monolithic microwave integrated circuit) technology. At the time of this reporting, these are reported to be the highest HBT amplifiers ever created. The purpose of the amplifier design is to evaluate the technology capability for high-frequency designs and verify the model for future development work.

  18. Numerical Analysis of Modal Instability Onset in Fiber Amplifiers (United States)


    Evolution of the logarithmic frequency spectrum of the off-center optical intensity probe along the length of the co-pumped amplifier for the case of...Evolution of the logarithmic frequency spectrum of the off-center optical intensity probe along the length of the counter-pumped amplifier for the...ABSTRACT 16. SECURITY CLASSIFICATION OF: Numerical analysis of the onset of modal instability in fiber amplifiers is presented. Specifically calculations

  19. [Post-translational ligation of split CFTR severed before TMD2 and its chloride channel function]. (United States)

    Zhu, Fuxiang; Gong, Xiandi; Liu, Zelong; Yang, Shude; Qu, Huige; Chi, Xiaoyan


    Mutations of cystic fibrosis transmembrane conductance regulator (CFTR) gene leads to cystic fibrosis, an autosomal recessive genetic disorder affecting a number of organs including the lung airways, pancreas and sweat glands. In order to investigate the post-translational ligation of CFTR with reconstructed functional chloride ion channel and the split Ssp DnaB intein-mediated protein trans-splicing was explored to co-deliver CFTR gene into eukaryotic cells with two vectors. The human CFTR cDNA was split after Glu838 codon before the second transmembrane dome (TMD2) into two halves of N- and C-parts and fused with the coding sequences of split Ssp DnaB intein. Pair of eukaryotic expression vectors pEGFP-NInt and pEYFP-IntC were constructed by inserting them into the vectors pEGFP-N1 and pEYFP-N1 respectively. The transient expression was carried out for observing the ligation of CFTR by Western blotting and recording the chloride current by patch clamps when cotransfection of the pair of vectors into baby hamster kidney (BHK) cells. The results showed that an obvious protein band proven to be ligated intact CFTR can be seen and a higher chloride current and activity of chloride channel were recorded after cotransfection. These data demonstrated that split Ssp DnaB intein could be used as a strategy in delivering CFTR gene by two vectors providing evidence for application of dual adeno-associated virus (AAV) vectors to overcome the limitation of packaging size in cystic fibrosis gene therapy.

  20. Evidence of Liquid Crystal-Assisted Abiotic Ligation of Nucleic Acids (United States)

    Fraccia, Tommaso P.; Zanchetta, Giuliano; Rimoldi, Valeria; Clark, Noel A.; Bellini, Tommaso


    The emergence of early life must have been marked by the appearance in the prebiotic era of complex molecular structures and systems, motivating the investigation of conditions that could not only facilitate appropriate chemical synthesis, but also provide the mechanisms of molecular selection and structural templating necessary to pilot the complexification toward specific molecular patterns. We recently proposed and demonstrated that these functions could be afforded by the spontaneous ordering of ultrashort nucleic acids oligomers into Liquid Crystal (LC) phases. In such supramolecular assemblies, duplex-forming oligomers are held in average end-to-end contact to form chemically discontinuous but physically continuous double helices. Using blunt ended duplexes, we found that LC formation could both provide molecular selection mechanisms and boost inter-oligomer ligation. This paper provides an essential extension to this notion by investigating the catalytic effects of LC ordering in duplexes with mutually interacting overhangs. Specifically, we studied the influence of LC ordering of 5'-hydroxy-3'-phosphate partially self-complementary DNA 14mers with 3'-CG sticky-ends, on the efficiency of non-enzymatic ligation reaction induced by water-soluble carbodiimide EDC as condensing agent. We investigated the ligation products in mixtures of DNA with poly-ethylene glycol (PEG) at three PEG concentrations at which the system phase separates creating DNA-rich droplets that organize into isotropic, nematic LC and columnar LC phases. We observe remarkable LC-enhanced chain lengthening, and we demonstrate that such lengthening effectively promotes and stabilizes LC domains, providing the kernel of a positive feedback cycle by which LC ordering promotes elongation, in turn stabilizing the LC ordering.

  1. Intermolecular DNA ligation activity of eukaryotic toposiomerase II: Potential roles in nucleic acid recombination

    Energy Technology Data Exchange (ETDEWEB)

    Gale, K.C.R.


    Single-stranded [phi]X174 (+) strand DNA was used as a model substrate for topoisomerase II to determine whether double-stranded DNA cleavage observed in vitro reflects the in vivo intermediate in the enzyme's catalytic cycle and to investigate potential mechanisms for topoisomerase II-mediated DNA recombination. As found previously for topoisomerase II-mediated cleavage of double-stranded DNA, the enzyme was covalently linked to the 5[prime]-termini of cleaved [phi]X174 molecules. Optimal reaction conditions were similar for the two substrates. In contrast to results with double-stranded molecules, single-stranded DNA cleavage increased with time, was not reversible, and did not require the presence of SDS. Cleavage products generated in the absence of protein denaturant contained free 3[prime]-OH DNA termini. These results strongly suggest that the covalent topoisomerase II-cleaved DNA complex observed in vitro is the active intermediate in the enzyme's catalytic code. Topoisomerase II is capable of joining cleaved [phi]X174 (+) strand DNA to duplex oligonucleotide acceptor molecules by an intermolecular ligation reaction. Intermolecular DNA ligation proceeded in a time and oligonucleotide concentration dependent fashion. The covalent linkage is between the 5[prime]-phosphate of [phi]X174 (+) strand DNA and the 3[prime]-OH of oligonucleotide acceptor molecules. The reaction was dependent on the presence of a divalent cation, was inhibited by salt, and was not affected by the presence of ATP. The enzyme was capable of ligating [phi]X174 (+) strand DNA to double-stranded oligonucleotides that contained 5[prime]-overhang, 3[prime]-overhang, or blunt ends. Single-stranded, nicked, or gapped oligonucleotides could also be used as acceptor molecules. These results demonstrate that the type II enzyme has an intrinsic ability to mediate illegitimate DNA recombination in vitro and suggests possible roles for topoisomerase II in nucleic acid recombination in vivo.

  2. Application of a pig ligated intestinal loop model for early Lawsonia intracellularis infection

    Directory of Open Access Journals (Sweden)

    Agerholm Jørgen S


    Full Text Available Abstract Background Porcine proliferative enteropathy in pigs is caused by the obligate, intracellular bacterium Lawsonia intracellularis. In vitro studies have shown close bacterium-cell interaction followed by cellular uptake of the bacterium within 3 h post inoculation (PI. However, knowledge of the initial in vivo interaction between porcine intestinal epithelium and the bacterium is limited. The aims of the present study were to evaluate the usefulness of a ligated small intestinal loop model to study L. intracellularis infections and to obtain information on the very early L. intracellularis-enterocyte interactions. Methods A ligated small intestinal loop model using three different L. intracellularis inocula was applied to 10-11-week-old pigs. The inocula were 1 wild type bacteria derived from overnight incubation of L. intracellularis bacteria from spontaneous disease, 2 crude vaccine bacteria (Enterisol® Ileitis Vet, and 3 vaccine bacteria propagated in cell culture. The bacteria-enterocyte interaction was visualised using immunohistochemistry on specimens derived 1, 3 and 6 h PI respectively. Results Although at a low level, close contact between bacteria and the enterocyte brush border including intracellular uptake of bacteria in mature enterocytes was seen at 3 and 6 h PI for the vaccine and the propagated vaccine inocula. Interaction between the wild-type bacteria and villus enterocytes was scarce and only seen at 6 h PI, where a few bacteria were found in close contact with the brush border. Conclusions The ligated intestinal loop model was useful with respect to maintaining an intact intestinal morphology for up to 6 h. Furthermore, the study demonstrated that L. intracellularis interacts with villus enterocytes within 3 to 6 h after inoculation into intestinal loops and that the bacterium, as shown for the vaccine bacteria, propagated as well as non-propagated, was able to invade mature enterocytes. Thus, the study demonstrates

  3. [Post-translational ligation and function of dual-vector transferred split CFTR gene]. (United States)

    Zhu, Fu-Xiang; Liu, Ze-Long; Qu, Hui-Ge; Chi, Xiao-Yan


    The mutation of cystic fibrosis transmembrane conductance regulator (CFTR) gene leads to an autosomal recessive genetic disorder cystic fibrosis (CF). The gene therapy for CF using adeno-associated virus (AAV) vectors delivering CFTR gene is restricted by the contents limitation of AAV vectors. In this study the split CFTR genes severed at its regulatory domain were delivered by a dual-vector system with an intein-mediated protein trans-splicing as a technique to investigate the post-translational ligation of CFTR half proteins and its function as a chloride ion channel. A pair of eukaryotic expression vectors was constructed by breaking the human CFTR cDNA before Ser712 codon and fusing with Ssp DnaB intein coding sequences. After co-transfection into baby hamster kidney (BHK) cells followed by transient expression, patch clamps were carried out to record the chloride current of whole-cell and the activity of a single channel, and the ligation of two halves of CFTR was observed by Western blotting. The results showed that the intein-fused half genes co-transfected cells displayed a high whole cell chloride current and activity of a single channel indicating the functional recovery of chloride channel, and an intact CFTR protein band was figured out by CFTR-specific antibodies indicating that intein can efficiently ligate the separately expressed half CFTR proteins. The data demonstrated that protein splicing strategy could be used as a strategy in delivering CFTR gene by two vectors, encouraging our ongoing research program on dual AAV vector system based gene transfer in gene therapy for cystic fibrosis.

  4. Dual Band High Efficiency Power Amplifier Based on CRLH Lines

    Directory of Open Access Journals (Sweden)

    D. Segovia-Vargas


    Full Text Available In this paper we propose the use of Composite Right/Left Hand (CRLH and Extended Composite Right/Left Hand (ECRLH transmission lines for the design of dual band high efficiency power amplifiers working in CE class. The harmonic termination can be synthesized using the meta-lines is particularly suitable for CE class amplifiers, which have a termination not as sensitive to the third harmonic as F class amplifier. This paper presents the design procedure and the design equations. The nonlinear phase response of a CRLH and ECRLH transmission line has been utilized to design arbitrary dual-band amplifiers.

  5. Nylon Sleeve for Cavity Amplifier Holds Tuning Despite Heat (United States)

    Derr, Lloyd


    The problem: Detuning of cavity amplifiers with change in temperature. This results in deterioration of the performance of the amplifier at its design frequency. In cavity amplifiers and filters it is desirable that constant performance be maintained regardless of thermal changes. These changes often cause an "off resonance shift" in a cavity filter and a deterioration of performance in a cavity amplifier. The solution: Mount the tuning probe in a nylon sleeve. Thermal expansion and contraction of the nylon nullifies unwanted capacitive and inductive changes in the resonant elements.

  6. Modeling a Common-Source Amplifier Using a Ferroelectric Transistor (United States)

    Sayyah, Rana; Hunt, Mitchell; MacLeond, Todd C.; Ho, Fat D.


    This paper presents a mathematical model characterizing the behavior of a common-source amplifier using a FeFET. The model is based on empirical data and incorporates several variables that affect the output, including frequency, load resistance, and gate-to-source voltage. Since the common-source amplifier is the most widely used amplifier in MOS technology, understanding and modeling the behavior of the FeFET-based common-source amplifier will help in the integration of FeFETs into many circuits.

  7. Controlling the dynamic range of a Josephson parametric amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Eichler, Christopher; Wallraff, Andreas [ETH Zuerich, Department of Physics, Zuerich (Switzerland)


    One of the central challenges in the development of parametric amplifiers is the control of the dynamic range relative to its gain and bandwidth, which typically limits quantum limited amplification to signals which contain only a few photons per inverse bandwidth. Here, we discuss the control of the dynamic range of Josephson parametric amplifiers by using Josephson junction arrays. We discuss gain, bandwidth, noise, and dynamic range properties of both a transmission line and a lumped element based parametric amplifier. Based on these investigations we derive useful design criteria, which may find broad application in the development of practical parametric amplifiers. (orig.)

  8. Pulse-distortion in a quantum-dot optical amplifier

    DEFF Research Database (Denmark)

    Romstad, Francis Pascal; Borri, Paola; Mørk, Jesper;


    Distortion of a -150fs optical pulse after propagation through an InAs/InGaAs quantum-dot optical amplifier is measured for different input energies an bias currents. Pulse distortion is observed and compared with results on a bulk amplifier.......Distortion of a -150fs optical pulse after propagation through an InAs/InGaAs quantum-dot optical amplifier is measured for different input energies an bias currents. Pulse distortion is observed and compared with results on a bulk amplifier....

  9. Combination ring cavity and backward Raman waveguide amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Kurnit, N.A.


    A combination regenerative ring and backward Raman waveguide amplifier and a combination regenerative ring oscillator and backward Raman waveguide amplifier which produce Raman amplification, pulse compression, and efficient energy extraction from the CO/sub 2/ laser pump signal for conversion into a Stokes radiation signal. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman waveguide amplifier. The backward Raman waveguide amplifier configuration extracts a major portion of the remaining energy from the CO/sub 2/ laser pump signal for conversion to Stokes radiation.

  10. Parametric Amplifiers for Microwave Kinectic Inductance Detector (MKID) Readout Project (United States)

    National Aeronautics and Space Administration — Find numerical solutions to the non-linear partial differential equations describing our amplifier transmission lines. Optimize periodic choke structure to block...

  11. A new resorbable device for ligation of blood vessels - A pilot study

    Directory of Open Access Journals (Sweden)

    Borg Niklas


    Full Text Available Abstract Background During surgery, controlled haemostasis to prevent blood loss is vital for a successful outcome. It can be difficult to ligate vessels located deep in the abdomen. A device that is easy to use and enables secure ligatures could be beneficial. Cable ties made of nylon have been used for ligation but the non-resorbable material caused tissue reactions. The objective of this study was to use a resorbable material to construct a device with a self-locking mechanism and to test its mechanical strength and ligation efficiency. Methods The device was manufactured by injection moulding of polydioxanone, a resorbable polymer used for suture materials. Polydioxanone with inherent viscosities of 1.9 dL/g and 1.3 dL/g were tested. The device consisted of a perforated flexible band which could be pulled through a case with a locking mechanism. After a first version of the device had been tested, some improvements were made. The locking case was downsized, corners were rounded off, the band was made thicker and the mould was redesigned to produce longer devices. Tensile tests were performed with the second version. The first version of the device was used to ligate the ovarian pedicle in a euthanized dog and to test echogenicity of the device with ultrasound. Compression of vessels of the ovarian pedicle was examined by histology. Both versions of the device were tested for haemostasis of and tissue grip on renal arteries in six anaesthetised pigs. Results The tensile strength of the flexible band of the devices with inherent viscosity of 1.9 dL/g was 50.1 ± 5.5 N (range 35.2-62.9 N, n = 11 and the devices with inherent viscosity of 1.3 dL/g had a tensile strength of 39.8 ± 8.1 N (range 18.6-54.2 N, n = 11. Injection moulding of the polymer with lower inherent viscosity resulted in a longer flow distance. Both versions of the device had an effective tissue grip and complete haemostasis of renal arteries was verified. The device attached

  12. Ligation of lymph vessels for the treatment of recurrent inguinal lymphoceles following lymphadenectomy

    DEFF Research Database (Denmark)

    Toyserkani, Navid Mohamadpour; Nielsen, Henrik Toft; Bakholdt, Vivi;


    used this technique since 2007 in our very severe cases and herein present our results. METHODS: The study was a retrospective case series in a university hospital setting. All patients who had this procedure performed were included from the first procedure performed in 2007 until August 2015......, and their data was retrieved from electronic patient records. RESULTS: In total, eight patients had this procedure performed for a total of ten inguinal regions. In all regions, leaking lymph vessels were easily found by the blue color and a median of 3 (range 1-5 vessels) vessels per region were ligated using...

  13. Biomimetic Synthesis of Insulin Enabled by Oxime Ligation and Traceless "C-Peptide" Chemical Excision. (United States)

    Thalluri, Kishore; Kou, Binbin; Gelfanov, Vasily; Mayer, John P; Liu, Fa; DiMarchi, Richard D


    For decades, insulin has represented a preeminent synthetic target. Recently introduced "biomimetic" strategies based on convertible single-chain precursors require incorporation of a chemical linker or a unique proteolytic site, which limits their practicality. In this approach the A- and B-chains are linked by two sequential oxime ligations followed by disulfide bond formation under redox conditions and linker excision by diketopiperazine (DKP) formation and ester hydrolysis, yielding native two-chain insulin. The method is expected to be applicable to any member of the insulin superfamily.

  14. Ligation-based mutation detection and RCA in surface un-modified OSTE+ polymer microfluidic chambers

    DEFF Research Database (Denmark)

    Saharil, Farizah; Ahlford, Annika; Kuhnemund, Malte;


    For the first time, we demonstrate DNA mutation detection in surface un-modified polymeric microfluidic chambers without suffering from bubble trapping or bubble formation. Microfluidic devices were manufactured in off-stoichiometry thiol-ene epoxy (OSTE+) polymer using an uncomplicated and rapid...... fabrication scheme. The device performance was compared to that of PMMA and PDMS devices. In OSTE+ devices, we were able to perform ligation-based mutation detection and rolling circle amplification (RCA) assays directly on the un-modified surface without suffering from bubble formation or enzyme inhibition...... during bio-operation at elevated temperatures. In contrast, PMMA, PDMS and COP microfluidic devices required specific surface treatment....

  15. Multiplexed homogeneous proximity ligation assays for high throughput protein biomarker research in serological material

    DEFF Research Database (Denmark)

    Lundberg, Martin; Thorsen, Stine Buch; Assarsson, Erika;


    A high throughput protein biomarker discovery tool has been developed based on multiplexed proximity ligation assays (PLA) in a homogeneous format in the sense of no washing steps. The platform consists of four 24-plex panels profiling 74 putative biomarkers with sub pM sensitivity each consuming...... only 1 micro Litre of human plasma sample. The system uses either matched monoclonal antibody pairs or the more readily available single batches of affinity purified polyclonal antibodies to generate the target specific reagents by covalently linking with unique nucleic acid sequences. These paired...

  16. Ligation of MHC class I molecules on peripheral blood T lymphocytes induces new phenotypes and functions

    DEFF Research Database (Denmark)

    Bregenholt, S; Röpke, M; Skov, S;


    Microgram concentrations of immobilized anti-MHC class I (MHC-I) Ab induced proliferation of resting CD3+ T cells from peripheral blood. In contrast, soluble Ab did not activate T cells. Exposure of T cells to immobilized anti-MHC-I Ab for only 24 h was followed by proliferation and development....... These data clearly demonstrate that ligation of the MHC-I complex on T cells may induce both positive and negative signals. Since the physiologic ligands for MHC-I molecules are TCR and the CD8 molecules, our data may suggest that MHC-I molecules are instrumental in cellular interactions between T cells....

  17. Management of anal fistula by ligation of the intersphincteric fistula tract

    DEFF Research Database (Denmark)

    Zirak-Schmidt, Samira; Perdawood, Sharaf


    INTRODUCTION: Ligation of the intersphincteric fistula tract (LIFT) is a sphincter-preserving procedure for treatment of anal fistulas described in 2007 by Rojanasakul et al. Several studies have since then assessed the procedure with varied results. This review assesses the relevant literature...... fistula treatment techniques were excluded. Only reports in English were included. Most reports were case studies with no control groups. One report could not be retrieved. RESULTS: A total of 19 original reports were assessed. Details concerning preoperative assessment, antibiotic usage and tract...

  18. Evaluation of seamless ligation cloning extract preparation methods from an Escherichia coli laboratory strain. (United States)

    Okegawa, Yuki; Motohashi, Ken


    Seamless ligation cloning extract (SLiCE) is a simple and efficient method for DNA cloning without the use of restriction enzymes. Instead, SLiCE uses homologous recombination activities from Escherichia coli cell lysates. To date, SLiCE preparation has been performed using an expensive commercially available lytic reagent. To expand the utility of the SLiCE method, we evaluated different methods for SLiCE preparation that avoid using this reagent. Consequently, cell extracts prepared with buffers containing Triton X-100, which is a common and low-cost nonionic detergent, exhibited sufficient cloning activity for seamless gene incorporation into a vector.

  19. Enzymes involved in DNA ligation and end-healing in the radioresistant bacterium Deinococcus radiodurans

    Directory of Open Access Journals (Sweden)

    Shevelev Igor V


    Full Text Available Abstract Background Enzymes involved in DNA metabolic events of the highly radioresistant bacterium Deinococcus radiodurans are currently examined to understand the mechanisms that protect and repair the Deinococcus radiodurans genome after extremely high doses of γ-irradiation. Although several Deinococcus radiodurans DNA repair enzymes have been characterised, no biochemical data is available for DNA ligation and DNA endhealing enzymes of Deinococcus radiodurans so far. DNA ligases are necessary to seal broken DNA backbones during replication, repair and recombination. In addition, ionizing radiation frequently leaves DNA strand-breaks that are not feasible for ligation and thus require end-healing by a 5'-polynucleotide kinase or a 3'-phosphatase. We expect that DNA ligases and end-processing enzymes play an important role in Deinococcus radiodurans DNA strand-break repair. Results In this report, we describe the cloning and expression of a Deinococcus radiodurans DNA ligase in Escherichia coli. This enzyme efficiently catalyses DNA ligation in the presence of Mn(II and NAD+ as cofactors and lysine 128 was found to be essential for its activity. We have also analysed a predicted second DNA ligase from Deinococcus radiodurans that is part of a putative DNA repair operon and shows sequence similarity to known ATP-dependent DNA ligases. We show that this enzyme possesses an adenylyltransferase activity using ATP, but is not functional as a DNA ligase by itself. Furthermore, we identified a 5'-polynucleotide kinase similar to human polynucleotide kinase that probably prepares DNA termini for subsequent ligation. Conclusion Deinococcus radiodurans contains a standard bacterial DNA ligase that uses NAD+ as a cofactor. Its enzymatic properties are similar to E. coli DNA ligase except for its preference for Mn(II as a metal cofactor. The function of a putative second DNA ligase remains unclear, but its adenylyltransferase activity classifies it as a

  20. Modeling and analysis of overmodulation in erbium-doped fiber amplifiers including amplified spontaneous emission (United States)

    Sharma, Reena; Raghuwanshi, Sanjeev Kumar


    Line surveillance and management information in erbium-doped fiber amplifiers (EDFAs) can be broadcast by modulating the amplitude of the low-frequency lightwave information signal, the process termed as overmodulation in the literature. This paper presents systematic solutions for the overmodulated pump and information signal transfer functions for EDFA. It includes amplified spontaneous emission (ASE) that has an impact on outcomes in the high-gain system. To the extent of our belief, the methodical model simulated with the current approach leads to a distinct perspective of an outcome in the respective field. The test bed described here is realistic. It specifically represents the overmodulation behavior in an EDFA under the influence of ASE.

  1. Optimal Relay Power Allocation for Amplify-and-Forward Relay Networks with Non-linear Power Amplifiers


    Zhang, Chao; Ren, Pinyi; Peng, Jingbo; Wei, Guo; Du, Qinghe; Wang, Yichen


    In this paper, we propose an optimal relay power allocation of an Amplify-and-Forward relay networks with non-linear power amplifiers. Based on Bussgang Linearization Theory, we depict the non-linear amplifying process into a linear system, which lets analyzing system performance easier. To obtain spatial diversity, we design a complete practical framework of a non-linear distortion aware receiver. Consider a total relay power constraint, we propose an optimal power allocation scheme to maxim...

  2. Wideband high efficiency CMOS envelope amplifiers for 4G LTE handset envelope tracking RF power amplifiers


    Hassan, Muhammad


    Fourth generation cellular networks offer performance similar to cable modems while allowing wide mobility. Although the use of orthogonal frequency division multiplexing in fourth generation increases its spectral efficiency but it also increases the peak-to-average power ratio of the transmitted signal. If a conventional power amplifier is used to transmit a high peak-to-average power ratio signal, then to meet the stringent linearity requirements, it will be operating 6 to 10 dB back-off f...

  3. A pilot randomized control study to evaluate endoscopic resection using a ligation device for rectal carcinoid tumors

    Institute of Scientific and Technical Information of China (English)

    Hiroyuki Sakata; Sadahiro Amemori; Kotaro Mannen; Masanobu Mizuguchi; Kazuma Fujimoto; Ryuichi Iwakiri; Akifumi Ootani; Seiji Tsunada; Shinichi Ogata; Hibiki Ootani; Ryo Shimoda; Kanako Yamaguchi; Yasuhisa Sakata


    AIM: Rectal carcinoid tumors smaller than 10 mm can be resected with local excision using endoscopy. In order to remove rectal carcinoid tumors completely, we evaluated endoscopic mucosal resection with a ligation device in this pilot control randomized study.METHODS: Fifteen patients were diagnosed with rectal carcinoid tumor (less than 10 mm) in our hospital from 1993 to 2002. There were 9 males and 6 females,with a mean age 61.5 years (range, 34-77 years).The patientshad no complaints of carcinoid syndrome symptoms. Fifteen patients were randomly divided into 2 groups: 7 carcinoid tumors were treated by conventional endoscopic resection, and 8 carcinoid tumors were treated by endoscopic resection using a ligation device.RESULTS: All rectal carcinoid tumors were located at the middle to distal rectum. The size of the tumors varied from 3 mm to 10 mm and background characteristics of the patients were not different in the two groups.The rate of complete removal of carcinoid tumors using a ligation device (100%, 8/8) was significantly higher than that of conventional endoscopic resection (57.1%,4/7). The three patients had tumor involvement of deep margin, for which additional treatment was performed.No complications occurred during or after endoscopic resection using a ligation device. All patients in the both groups were alive during the 3-year observation period.CONCLUSION: Endoscopic resection using a ligation device is a useful and safe method for resection of small rectal carcinoid tumors.

  4. Alterations in plaque accumulation and gingival inflammation promoted by treatment with self-ligating and conventional orthodontic brackets

    Directory of Open Access Journals (Sweden)

    Mauricio de Almeida Cardoso


    Full Text Available OBJECTIVE: The aim of the present study was to evaluate, comparatively, the periodontal response during orthodontic treatment performed with self-ligating and conventional brackets. METHODS: Sixteen Caucasian individuals of both sexes, aged between 12 and 16 years old and in permanent dentition were selected. Eight individuals were treated with conventional brackets installed on the lower dental arch and self-ligating brackets on the upper arch. Another eight individuals received self-ligating brackets in the lower arch and conventional brackets in the upper arch. The subjects received material and instructions for oral hygiene. Visible plaque index (VPI, gingival bleeding index (GBI and clinical attachment level (CAL were evaluated just after installation of orthodontic appliances, and 30, 60 and 180 days later. Mann-Whitney test was used to compare differences between groups (self-ligating and conventional, two-way ANOVA followed by Tukey's test was used to assess CAL at each site of each tooth. Significance level was set at 5%. RESULTS: No significant changes were found with regard to the assessed parameters (VPI, GBI and CAL in either one of the systems. CONCLUSION: No significant changes were found with regard to the periodontal response to orthodontic treatment for the variables assessed and between subjects receiving passive self-ligating and conventional brackets. All individuals had received oral hygiene instructions and had their periodontal conditions monitored.

  5. Sensitive detection of mRNA decay products by use of reverse-ligation-mediated PCR (RL-PCR). (United States)

    Grange, Thierry


    Ligation-mediated PCR allows the detection and mapping of cleavage products of specific nucleic acid molecules out of complex nucleic acid mixtures. It can be applied to the detection of either degradation products of exogenously added nucleases in footprinting applications or natural decay products or reaction intermediates. We have developed various ligation-mediated PCR approaches to analyze mRNAs, all relying on RNA ligation, followed by reverse-transcription and PCR amplification. We have termed these approaches reverse-ligation-mediated PCR (RL-PCR). The ligation event involves either an RNA linker added to the 5'-end of cleaved RNA or RNA circularization, allowing, respectively, the mapping and quantification of the cleavage points or the simultaneous analysis of the presence or absence of the 5'-cap structure and the length of the poly(A) tail. These methods enabled us to develop a very efficient 5'-RACE procedure to map mRNA 5'-ends, to footprint in permeabilized cells the interaction of regulatory proteins with RNA, to detect the products of cellular ribozyme action and to analyze cellular decay pathways that involve deadenylation and/or decapping. I review herein the methodologic aspects and protocols of the various RL-PCR procedures we have developed.

  6. Development of 3 kW at 325 MHz solid-state RF power amplifier using four power amplifier modules

    Energy Technology Data Exchange (ETDEWEB)

    Ramarao, B.V., E-mail: [Ion Accelerator Development Division, Bhabha Atomic Research Center, Mumbai 400085 (India); Sonal, S.; Mishra, J.K.; Pande, M.; Singh, P. [Ion Accelerator Development Division, Bhabha Atomic Research Center, Mumbai 400085 (India); Kumar, G.; Mukherjee, J. [Indian Institute of Technology, Powai, Mumbai 400076 (India)


    A high power solid-state RF power amplifier of 3 kW at 325 MHz has been developed using only four RF power amplifier modules of 850 W power output each. The design and characterization of RF power modules have been presented. A four way Wilkinson power combiner adds the output of four power amplifier modules with a total transmission loss of less than 6%. The combined power amplifier has a power gain of 20.2 dB at 1-dB compression point, and the corresponding output power is 2.8 kW at 325 MHz. The drain efficiency of the power amplifier is 65.3% at 3 kW. All the harmonics of this amplifier are below −40 dBc. The amplifier has better characteristics like fewer numbers of active devices per kilo watt, high efficiency, high gain, and ruggedness etc for RF accelerator applications. -- Highlights: • High gain power amplifier, power gain at 20 dB. • High efficiency amplifier, efficiency >65%. • Minimum number of modules per kilo watt power output. • Heat sink with modules on both side, high density.

  7. Long-term outcome and efficacy of endoscopic hemorrhoid ligation for symptomatic internal hemorrhoids

    Institute of Scientific and Technical Information of China (English)

    Ming-Yao Su; Cheng-Tang Chiu; Wei-Pin Lin; Chen-Ming Hsu; Pang-Chi Chen


    AIM: To assess the long-term outcome of endoscopic hemorrhoid ligation (EHL) for the treatment of symptomatic internal hemorrhoids. METHODS: A total of 759 consecutive patients (415 males and 344 females) were enrolled. Clinical presentations were rectal bleeding (593 patients) and mucosal prolapse (166 patients). All patients received EHL at outpatient clinics. Hemorrhoid severity was classified by Goligher's grading. The mean follow-up period was 55.4 mo (range, 45-92 mo). RESULTS: The number of band ligations averaged 2.35 in the first session for bleeding and 2.69 for prolapsed patients. Bleeding was controlled in 587 (98.0%) patients, while prolapse was reduced in 137 (82.5%) patients. After treatment, 93 patients experienced anal pain and 48 patients had mild bleeding. Patient subjective satisfaction was 93.6%. Repeat treatment or surgery was performed if symptoms were not relieved in the first session. In the bleeding group, the recurrence rate was 3.7% (22 patients) at 1 year, and 6.6% and 13.0% at 2 and 5 years. In the prolapsed group, the recurrence rate was 3.0%, 9.6% and 16.9% at 1, 2 and 5 years, respectively. CONCLUSION: EHL is an easy and well-tolerated procedure for the treatment of symptomatic internal hemorrhoids, with good long-term results.

  8. Prospective randomized comparison of transumbilical two-port laparoscopic and conventional laparoscopic varicocele ligation (United States)

    Zhang, Guo-Xi; Yang, Jun; Long, Da-Zhi; Liu, Min; Zou, Xiao-Feng; Yuan, Yuan-Hu; Xiao, Ri-Hai; Xue, Yi-Jun; Zhong, Xin; Liu, Quan-Liang; Liu, Fo-Lin; Jiang, Bo; Xu, Rui-Quan; Xie, Kun-Lin


    We have established a novel method named transumbilical two-port laparoscopic varicocele ligation (TTLVL) for varicocele, which is still needed to evaluate. In this study, 90 patients with left idiopathic symptomatic varicoceles of grades II–III according to the Dubin grading system were randomly assigned to TTLVL (n = 45) and conventional laparoscopic varicocele ligation (CLVL) (n = 45). The demographic, intraoperative, postoperative, and follow-up data were recorded and compared between the two groups. All the procedures in the two groups were completed successfully with no intraoperative complications and no conversions to open surgery. No significant difference was found in the operative time, resuming ambulation, bowel recovery, postoperative hospital stay, and postoperative resolution of scrotal pain between the two groups (P > 0.05). However, the postoperative mean visual analog pain scale scores for TTLVL group were all less at 24 h, 48 h, 72 h, and 7 days postoperatively compared to CLVL (P = 0.001, 0.010, 0.006, and 0.027, respectively). The mean patient scar assessment questionnaire score in postoperative month 3 was 29.7 for TTLVL group compared with 32.1 for CLVL group (P < 0.001). There was no testicular atrophy observed in both groups during the follow-up period. The study shows that TTLVL is a safe, feasible, and effective minimally invasive surgical alternative to CLVL for the treatment of varicocele. Compared with CLVL, TTLVL may decrease postoperative pain and improve the cosmetic outcomes. PMID:26732104

  9. Design and validation of DNA libraries for multiplexing proximity ligation assays. (United States)

    Gobet, Nicolas; Ketterer, Simon; Meier, Matthias


    Here, we present an in silico, analytical procedure for designing and testing orthogonal DNA templates for multiplexing of the proximity ligation assay (PLA). PLA is a technology for the detection of protein interactions, post-translational modifications, and protein concentrations. To enable multiplexing of the PLA, the target information of antibodies was encoded within the DNA template of a PLA, where each template comprised four single-stranded DNA molecules. Our DNA design procedure followed the principles of minimizing the free energy of DNA cross-hybridization. To validate the functionality, orthogonality, and efficiency of the constructed template libraries, we developed a high-throughput solid-phase rolling-circle amplification assay and solid-phase PLA on a microfluidic platform. Upon integration on a microfluidic chip, 640 miniaturized pull-down assays for oligonucleotides or antibodies could be performed in parallel together with steps of DNA ligation, isothermal amplification, and detection under controlled microenvironments. From a large computed PLA template library, we randomly selected 10 template sets and tested all DNA combinations for cross-reactivity in the presence and absence of antibodies. By using the microfluidic chip application, we determined rapidly the false-positive rate of the design procedure, which was less than 1%. The combined theoretical and experimental procedure is applicable for high-throughput PLA studies on a microfluidic chip.

  10. Bile duct ligation in mice: induction of inflammatory liver injury and fibrosis by obstructive cholestasis. (United States)

    Tag, Carmen G; Sauer-Lehnen, Sibille; Weiskirchen, Sabine; Borkham-Kamphorst, Erawan; Tolba, René H; Tacke, Frank; Weiskirchen, Ralf


    In most vertebrates, the liver produces bile that is necessary to emulsify absorbed fats and enable the digestion of lipids in the small intestine as well as to excrete bilirubin and other metabolic products. In the liver, the experimental obstruction of the extrahepatic biliary system initiates a complex cascade of pathological events that leads to cholestasis and inflammation resulting in a strong fibrotic reaction originating from the periportal fields. Therefore, surgical ligation of the common bile duct has become the most commonly used model to induce obstructive cholestatic injury in rodents and to study the molecular and cellular events that underlie these pathophysiological mechanisms induced by inappropriate bile flow. In recent years, different surgical techniques have been described that either allow reconnection or reanastomosis after bile duct ligation (BDL), e.g., partial BDL, or other microsurgical methods for specific research questions. However, the most frequently used model is the complete obstruction of the common bile duct that induces a strong fibrotic response after 21 to 28 days. The mortality rate can be high due to infectious complications or technical inaccuracies. Here we provide a detailed surgical procedure for the BDL model in mice that induce a highly reproducible fibrotic response in accordance to the 3R rule for animal welfare postulated by Russel and Burch in 1959.

  11. Rubber band ligation for 750 cases of symptomatic hemorrhoids out of 2200 cases

    Institute of Scientific and Technical Information of China (English)

    Ayman M El Nakeeb; Hisham H Abd Elmoniam; Waiel W Khafagy; Mosaad H Horshed; Ramadan E El Lithy; Mohamed E Farid; Amir A Fikry; Waleed H Omar; Elyamani M Fouda; Tito A El Metwally; Hosam E Ghazy; Sabry A Badr; Mohmed Y Abu Elkhar; Salih M Elawady


    AIM: To study the results for the treatment of symptomatic hemorrhoids using rubber band ligation (RBL) method. METHODS: A retrospective study for 750 patients who came to the colorectal unit from June, 1998 to September, 2006, data was retrieved from archived files. RBL was performed using the Mc Gown applicator on an outpatient basis. The patients were asked to return to out-patient clinic for follow up at 2 wk, 1 mo, 6 mo and through telephone call every 6 mo for 2 years). RESULTS: After RBL, 696 patients (92.8%) were cured with no difference in outcome for second or third degree hemorrhoids (P = 0.31). Symptomatic recurrence was detected in 11.04% after 2 years. A total of 52 patients (6.93%) had 77 complications from RBL which required no hospitalization. Complications were pain, rectal bleeding and vaso-vagal symptoms (4.13%, 4.13% and 1.33% of patients, respectively). At 1 mo there were a significant improvement in mean SF-36 scores over baseline in five items, while after 2 years there were improvement in all items over baseline, but not significant. No significant manometeric changes after band ligation. CONCLUSION: RBL is a simple, safe and effective method for treating symptomatic second and third degree hemorrhoids as an out patient procedure with significant improvement in quality of life. RBL doesn't alter ano-rectal functions.

  12. Simultaneous bile duct and portal venous branch ligation in two-stage hepatectomy

    Institute of Scientific and Technical Information of China (English)

    Hiroya Iida; Chiaki Yasui; Tsukasa Aihara; Shinichi Ikuta; Hidenori Yoshie; Naoki Yamanaka


    Hepatectomy is an effective surgical treatment for multiple bilobar liver metastases from colon cancer; however, one of the primary obstacles to completing surgical resection for these cases is an insufficient volume of the future remnant liver, which may cause postoperative liver failure. To induce atrophy of the unilateral lobe and hypertrophy of the future remnant liver, procedures to occlude the portal vein have been conventionally used prior to major hepatectomy. We report a case of a 50-year-old woman in whom two-stage hepatectomy was performed in combination with intraoperative ligation of the portal vein and the bile duct of the right hepatic lobe. This procedure was designed to promote the atrophic effect on the right hepatic lobe more effectively than the conventional technique, and to the best of our knowledge, it was used for the first time in the present case. Despite successful induction of liver volume shift as well as the following procedure, the patient died of subsequent liver failure after developing recurrent tumors. We discuss the first case in which simultaneous ligation of the portal vein and the biliary system was successfully applied as part of the first step of two-stage hepatectomy.

  13. Prospective randomized comparison of transumbilical two-port laparoscopic and conventional laparoscopic varicocele ligation

    Directory of Open Access Journals (Sweden)

    Guo-Xi Zhang


    Full Text Available We have established a novel method named transumbilical two-port laparoscopic varicocele ligation (TTLVL for varicocele, which is still needed to evaluate. In this study, 90 patients with left idiopathic symptomatic varicoceles of grades II-III according to the Dubin grading system were randomly assigned to TTLVL (n = 45 and conventional laparoscopic varicocele ligation (CLVL (n = 45. The demographic, intraoperative, postoperative, and follow-up data were recorded and compared between the two groups. All the procedures in the two groups were completed successfully with no intraoperative complications and no conversions to open surgery. No significant difference was found in the operative time, resuming ambulation, bowel recovery, postoperative hospital stay, and postoperative resolution of scrotal pain between the two groups (P > 0.05. However, the postoperative mean visual analog pain scale scores for TTLVL group were all less at 24 h, 48 h, 72 h, and 7 days postoperatively compared to CLVL (P = 0.001, 0.010, 0.006, and 0.027, respectively. The mean patient scar assessment questionnaire score in postoperative month 3 was 29.7 for TTLVL group compared with 32.1 for CLVL group (P < 0.001. There was no testicular atrophy observed in both groups during the follow-up period. The study shows that TTLVL is a safe, feasible, and effective minimally invasive surgical alternative to CLVL for the treatment of varicocele. Compared with CLVL, TTLVL may decrease postoperative pain and improve the cosmetic outcomes.

  14. CD28 ligation increases macrophage suppression of T-cell proliferation. (United States)

    Silberman, Daniel; Bucknum, Amanda; Bartlett, Thomas; Composto, Gabriella; Kozlowski, Megan; Walker, Amanda; Werda, Amy; Cua, Jackelyn; Sharpe, Arlene H; Somerville, John E; Riggs, James E


    When compared to spleen or lymph node cells, resident peritoneal cavity cells respond poorly to T-cell activation in vitro. The greater proportional representation of macrophages in this cell source has been shown to actively suppress the T-cell response. Peritoneal macrophages exhibit an immature phenotype (MHC class II(lo), B7(lo)) that reduces their efficacy as antigen-presenting cells. Furthermore, these cells readily express inducible nitric oxide synthase (iNOS), an enzyme that promotes T-cell tolerance by catabolism of the limiting amino acid arginine. Here, we investigate the ability of exogenous T-cell costimulation to recover the peritoneal T-cell response. We show that CD28 ligation failed to recover the peritoneal T-cell response and actually suppressed responses that had been recovered by inhibiting iNOS. As indicated by cytokine ELISpot and neutralizing monoclonal antibody (mAb) treatment, this 'cosuppression' response was due to CD28 ligation increasing the number of interferon (IFN)-γ-secreting cells. Our results illustrate that cellular composition and cytokine milieu influence T-cell costimulation biology.Cellular & Molecular Immunology advance online publication, 23 April 2012; doi:10.1038/cmi.2012.13.

  15. Ligation of the adhesion-GPCR EMR2 regulates human neutrophil function. (United States)

    Yona, Simon; Lin, Hsi-Hsien; Dri, Pietro; Davies, John Q; Hayhoe, Richard P G; Lewis, Sion M; Heinsbroek, Sigrid E M; Brown, K Alun; Perretti, Mauro; Hamann, Jörg; Treacher, David F; Gordon, Siamon; Stacey, Martin


    At present, approximately 150 different members of the adhesion-G protein-coupled receptor (GPCR) family have been identified in metazoans. Surprisingly, very little is known about their function, although they all possess large extracellular domains coupled to a seven-transmembrane domain, suggesting a potential role in cell adhesion and signaling. Here, we demonstrate how the human-restricted adhesion-GPCR, EMR2 (epidermal growth factor-like module-containing mucin-like hormone receptor), regulates neutrophil responses by potentiating the effects of a number of proinflammatory mediators and show that the transmembrane region is critical for adhesion-GPCR function. Using an anti-EMR2 antibody, ligation of EMR2 increases neutrophil adhesion and migration, and augments superoxide production and proteolytic enzyme degranulation. On neutrophil activation, EMR2 is rapidly translocated to membrane ruffles and the leading edge of the cell. Further supporting the role in neutrophil activation, EMR2 expression on circulating neutrophils is significantly increased in patients with systemic inflammation. These data illustrate a definitive function for a human adhesion-GPCR within the innate immune system and suggest an important role in potentiating the inflammatory response. Ligation of the adhesion-GPCR EMR2 regulates human neutrophil function.

  16. Comparison of static friction with self-ligating, modified slot design and conventional brackets

    Directory of Open Access Journals (Sweden)

    Raquel Morais Castro


    Full Text Available OBJECTIVE: To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters. MATERIAL AND METHODS: The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA, with a modified slot design (Mini Uni TwinTM, 3M/Unitek, Monrovia, USA and conventional (Kirium, Abzil, São José do Rio Preto, Brazil. The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA. The static frictional force was measured using a universal testing machine (DL 500, EMIC®, São José dos Pinhais, Brazil with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni's post hoc test. RESULTS: There was a significant difference (p<0.05 in static friction when the three types of brackets were tested with the same wire size. The wire diameter influenced friction only when the brackets had a 10º angulation (p<0.05. The angulation influenced friction (p<0.05 when the brackets were associated with a 0.018" wire. CONCLUSION: Brackets with a modified slot design showed intermediate static frictional force values between the conventional and self-ligating brackets tested.

  17. Electronic Structure of Ligated CdSe Clusters: Dependence on DFT Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Albert, VV; Ivanov, SA; Tretiak, S; Kilina, SV


    Simulations of ligated semiconductor quantum dots (QDs) and their physical properties, such as morphologies, QD-ligand interactions, electronic structures, and optical transitions, are expected to be very sensitive to computational methodology. We utilize Density Functional Theory (DFT) and systematically study how the choice of density functional, atom-localized basis set, and a solvent affects the physical properties of the Cd{sub 33}Se{sub 33} cluster ligated with a trimethyl phosphine oxide ligand. We have found that qualitative performance of all exchange-correlation (XC) functionals is relatively similar in predicting strong QD-ligand binding energy ({approx}1 eV). Additionally, all functionals predict shorter Cd-Se bond lengths on the QD surface than in its core, revealing the nature and degree of QD surface reconstruction. For proper modeling of geometries and QD-ligand interactions, however, augmentation of even a moderately sized basis set with polarization functions (e.g., LANL2DZ* and 6-31G*) is very important. A polar solvent has very significant implications for the ligand binding energy, decreasing it to 0.2-0.5 eV. However, the solvent model has a minor effect on the optoelectronic properties, resulting in persistent blue shifts up to {approx}0.3 eV of the low-energy optical transitions. For obtaining reasonable energy gaps and optical transition energies, hybrid XC functionals augmented by a long-range Hartree-Fock orbital exchange have to be applied.

  18. Peripancreatic artery ligation and artery infusion chemotherapy for advanced pancreatic carcinoma

    Institute of Scientific and Technical Information of China (English)

    纪宗正; 王永向; 陈熹; 吴涛


    Objective To develop a new treatment for advanced pancreatic carcinoma. Methods Twenty-nine patients with advanced pancreatic carcinoma (12 patients with liver metastasis at the same time) were randomly divided into two groups. In group A (n=11), patients underwent bilio-enterostomy and/or gastro-enterostomy combined with systemic chemotherapy after surgery. In group B (n=18), patients underwent bilio-enterostomy and/or gastro-enterostomy combined with peripancreatic arterial ligation and arterial infusion regional chemotherapy. Twenty-four patients were followed up for 3-18 months. The palliation of clinical symptoms, changes in carcinoma size by B ultrasound (BUS) and CT scan, survival period and serum carcinoembryonic antigen (CEA) were observed and compared between the two groups. Results Symptoms were alleviated in most patients in group B, and BUS and CT scan showed that tumor volume decreased in group B. The response rate was 66.7% in group B and 18.2% in group A (P0.05). Conclusion Peripancreatic arterial ligation combined with arterial infusion regional chemotherapy is effective against both pancreatic carcinoma and with liver metastases. It can alleviate clinical symptoms, postpone the growth rate of tumor and prolong the survival period.


    Institute of Scientific and Technical Information of China (English)

    ZHONG Yi-sheng; CAI Kang; CHENG Yu; JIAO Qin; LIU Xiao-hong; YAO Hui-ping; ZHOU Xiao-qing


    Objective To develop and evaluate the rat model of chronic glaucoma by episcleral veins ligation (EVL). Methods Experimental glaucoma was induced unilaterally in 28 male Sprague-Dawley rats by ligating two episcleral veins. Intraocular pressure (IOP) in rats was measured by a Goldmann applanation tonometer under 3% pentobarbital sodium anesthesia. The optic nerve head and retinal vasculature were assessed by repeated fundus examinations. The amount of optic nerve axons was assessed by Image-Pro Plus image analysis system in a masked fashion. Results IOP without EVL was (19.21±1.23)mmHg, whereas the EVL eyes gained about 1.8-fold higher IOP [(33.96±2.73)mmHg] after EVL immediately (P<0.001). The elevated IOP gradually decreased over time. However, the differences were kept significant up to 8 weeks after EVL. The IOP was reduced to similar levels as contralateral eyes at 12 and 16 weeks after EVL. The glaucomatous optic nerve excavation appeared in EVL eyes at 8 weeks after EVL, and the optic nerve excavation enlarged gradually with the increasing post-operation time. The amount of optic nerve axons also significantly decreased in EVL eyes at 8 weeks after EVL, and the amount of axons decreased gradually with the increasing post-operation time. Conclusion Increase of IOP caused by EVL represents a useful and efficient model of experimental glaucoma in rats.

  20. Dang Gui Bu Xue Tang ameliorates coronary artery ligation-induced myocardial ischemia in rats. (United States)

    Chunhua, Ma; Hongyan, Long; Weina, Zhu; Xiaoli, He; Yajie, Zhang; Jie, Ruan


    Dang The present study was designed to investigate cardioprotective effects of Dang Gui Bu Xue Tang (DGBUT) on coronary artery ligation-induced myocardial ischemia. Myocardial ischemia (MI) model was induced in SD rats by surgical ligation of the left anterior descending coronary artery. ST segment elevation of Electrocardiograph (ECG) infarct size, levels of lactate dehydrogenase (LDH), creatine kinase (CK), glutathione (GSH) and catalase (CAT), catalase (SOD), malondialdehyde (MDA), and inflammatory cytokines and phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38, c-Jun NH2 terminal kinases (JNK), nuclear factor (NF)-κBp65, inhibitory kappa B (IκB) α, IκB kinase (IKK) α and IKKβ were evaluated in rats treated with or without DGBUT. DGBUT treatment significantly reduced the elevation of the ST segment of ECG, the myocardial infarct size of MI. The level of LDH, CK and MDA were suppressed, the contents of SOD, GSH and CAT were enhanced with DGBUT. The elevated concentration of inflammatory cytokines tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and IL-6 in MI rats were effectively reversed by the DGBUT administration. Also, highly expressed p-JNK, p-ERK, p-p38, p-NF-κBp65, p-IκBα, p-IKKα and p-IKKβ in MI rats were restored respectively by DGBUT treatment. The protective effect of DGBUT against MI injury might be associated with MAPK/NF-кB pathway.

  1. Electrochemical detection of aqueous Ag+ based on Ag+-assisted ligation reaction (United States)

    Miao, Peng; Han, Kun; Wang, Bidou; Luo, Gangyin; Wang, Peng; Chen, Mingli; Tang, Yuguo


    In this work, a novel strategy to fabricate a highly sensitive and selective biosensor for the detection of Ag+ is proposed. Two DNA probes are designed and modified on a gold electrode surface by gold-sulfur chemistry and hybridization. In the presence of Ag+, cytosine-Ag+-cytosine composite forms and facilitates the ligation event on the electrode surface, which can block the release of electrochemical signals labeled on one of the two DNA probes during denaturation process. Ag+ can be sensitively detected with the detection limit of 0.1 nM, which is much lower than the toxicity level defined by U.S. Environmental Protection Agency. This biosensor can easily distinguish Ag+ from other interfering ions and the performances in real water samples are also satisfactory. Moreover, the two DNA probes are designed to contain the recognition sequences of a nicking endonuclease, and the ligated DNA can thus be cleaved at the original site. Therefore, the electrode can be regenerated, which allows the biosensor to be reused for additional tests.

  2. Peptide Conjugation to a Polymer Coating via Native Chemical Ligation of Azlactones for Cell Culture. (United States)

    Schmitt, Samantha K; Trebatoski, David J; Krutty, John D; Xie, Angela W; Rollins, Benjamin; Murphy, William L; Gopalan, Padma


    Conjugation of biomolecules for stable presentation is an essential step toward reliable chemically defined platforms for cell culture studies. In this work, we describe the formation of a stable and site-specific amide bond via the coupling of a cysteine terminated peptide at low concentration to an azlactone containing copolymer coating. A copolymer of polyethylene glycol methyl ether methacrylate-ran-vinyl azlactone-ran-glycidyl methacrylate P(PEGMEMA-r-VDM-r-GMA) was used to form a thin coating (20-30 nm) on silicon and polycarbonate substrates. The formation and stability of coating-peptide bonds for peptides containing free thiols and amines were quantified by X-ray photoelectron spectroscopy (XPS) after exposure to cell culture conditions. Peptides containing a thiol as the only nucleophile coupled via a thioester bond; however, the bond was labile under cell culture conditions and almost all the bound peptides were displaced from the surface over a period of 2 days. Coupling with N-terminal primary amine peptides resulted in the formation of an amide bond with low efficiency (chemical ligation. Through a combination of XPS and cell culture studies, we show that the cysteine terminated peptides undergo a native chemical ligation process at low peptide concentration in aqueous media, short reaction time, and at room temperature resulting in the stable presentation of peptides beyond 2 weeks for cell culture studies.

  3. Sequencing by ligation variation with endonuclease V digestion and deoxyinosine-containing query oligonucleotides

    Directory of Open Access Journals (Sweden)

    Ho Antoine


    Full Text Available Abstract Background Sequencing-by-ligation (SBL is one of several next-generation sequencing methods that has been developed for massive sequencing of DNA immobilized on arrayed beads (or other clonal amplicons. SBL has the advantage of being easy to implement and accessible to all because it can be performed with off-the-shelf reagents. However, SBL has the limitation of very short read lengths. Results To overcome the read length limitation, research groups have developed complex library preparation processes, which can be time-consuming, difficult, and result in low complexity libraries. Herein we describe a variation on traditional SBL protocols that extends the number of sequential bases that can be sequenced by using Endonuclease V to nick a query primer, thus leaving a ligatable end extended into the unknown sequence for further SBL cycles. To demonstrate the protocol, we constructed a known DNA sequence and utilized our SBL variation, cyclic SBL (cSBL, to resequence this region. Using our method, we were able to read thirteen contiguous bases in the 3' - 5' direction. Conclusions Combining this read length with sequencing in the 5' - 3' direction would allow a read length of over twenty bases on a single tage. Implementing mate-paired tags and this SBL variation could enable > 95% coverage of the genome.

  4. Comparison of emergency endoscopic variceal ligation plus octride or octride alone for acute esophageal variceal bleeding

    Institute of Scientific and Technical Information of China (English)

    LIU Jin-song; LIU Jun


    Background Octride was the main method for the treatment of esophageal variceal bleeding (EVB). The aim of this study was to compare the cost-effect and safety between esophageal variceal ligation (EVL) plus octride and octride alone in acute esophageal bleeding.Methods A total of 101 cirrhotic patients with EVB were involved in this study and received emergency EVL+octride (EVL group) or only octride therapy randomly. The cost, efficacy and safety were analyzed and compared between the two groups.Results Among 51 patients in EVL group, 5 (10%) patients failed. Among 50 patients in the octride treatment group, 13 patients (26%) failed. The difference was significant (P<0.05). The average blood transfusion volume was (2.4±2.2) units in the EVL group and (6.4±3.4) units in the octride treatment group (P <0.05). Hospital stay was (7.4±1.3) days in the EVL group and (11.4±3.3) days in the octride treatment group (P<0.05). The average hospital cost was (10 983±1147) yuan in the EVL group and (13 921 ±2107) yuan in the octride treatment group (P<0.05). Conclusion Emergency endoscopic ligation plus octride is superior to octride alone in the treatment of acute EVB with lower cost and higher efficacy with enough safety.

  5. Risk factors for predicting early variceal rebleeding after endoscopic variceal ligation

    Institute of Scientific and Technical Information of China (English)

    Liang Xu; Feng Ji; Qin-Wei Xu; Mie-Qing Zhang


    AIM: To analyze the clinical risk factors for early variceal rebleeding after endoscopic variceal ligation (EVL). METHODS: 342 cirrhotic patients with esophageal varices who received elective EVL to prevent bleeding or rebleeding at our endoscopy center between January 2005 and July 2010. were included in this study. The early rebleeding cases after EVL were confirmed by clinical signs or endoscopy. A case-control study was performed comparing the patients presenting with early rebleeding with those without this complication. RESULTS: The incidence of early rebleeding after EVL was 7.60%, and the morbidity of rebleeding was 26.9%. Stepwise multivariate logistic regression analysis showed that four variables were independent risk factors for early rebleeding: moderate to excessive ascites [odds ratio (OR) 62.83, 95% CI: 9.39-420.56, P 18 s (OR 11.35, 95% CI: 1.93-66.70, P = 0.007). CONCLUSION: The early rebleeding rate after EVL is mainly affected by the volume of ascites, number of rubber bands used to ligate, severity of varices and prolonged PT. Effective measures for prevention and treatment should be adopted before and after EVL.


    Directory of Open Access Journals (Sweden)

    Sharath S S


    Full Text Available Peptic ulcer disease is a chronic problem of the gastrointestinal tract characterized by mucosal damage secondary to pepsin and gastric acid secretion. Herbal medicines are generally used in cases when drugs are to be used for chronic periods. The study was conducted to evaluate antiulcerogenic activity of convolvulus pluricaulis in wistar rats. The antiulcer activity was carried out employing - Pyloric ligation method. The rats were randomly divided into 4 groups of 6 animals each. First group was given 1ml of 0.1% of vehicle (Tween 80; the second group was treated with ranitidine 50 mg/kg in 1 ml Tween 80. The remaining groups receive 200 mg/kg and 400 mg/kg of Convolvulus pluricaulis alcoholic extract (CPAE in 1 ml Tween 80 respectively. All the drugs were administered orally for five days duration daily in two divided doses. Evaluation of antiulcer activity was done by Ulcer score/ulcer index. Volume of gastric juice secreted, gastric free acidity, total acidity, total protein, pepsin mucin and pH were also estimated. CPAE at a dose of 200 mg/kg inhibited ulcer index by 40.87% and at a dose of 400 mg/kg inhibited ulcer index by 26.64 %. Alcoholic extracts of Convolvulus pluricaulis have shown a significant protection against gastric ulcers in pyloric ligation model.

  7. Gain characteristics of a saturated fiber optic parametric amplifier

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Lorenzen, Michael Rodas; Noordegraaf, Danny


    In this work we discuss saturation performance of a fiber optic parametric amplifier. A simple numerical model is described and applied to specific cases. A system experiment using a saturated amplifier illustrates a 4 dB improvement in required signal to noise ratio for a fixed bit error ratio....

  8. Optically amplifying planar glass waveguides: Laser on a chip

    DEFF Research Database (Denmark)

    Guldberg-Kjær, Søren Andreas

    The objective of this work was to devlop optically amplifying planar wavguides, using erbium-doped germano-silicate glass films deposited by PECVD (Plasma Enhanced Chemical Vapour Deposition). The waveguides should exhibit enough gain to be useful as optical amplifiers in integrated planar lightw...

  9. The design of erbium-doped fiber amplifiers

    DEFF Research Database (Denmark)

    Pedersen, Bo; Bjarklev, Anders Overgaard; Povlsen, Jørn Hedegaard


    An accurate model for the erbium-doped fiber amplifier is presented. The model is used to design the index profile of the doped fiber, optimizing with regard to efficiency for inline- and preamplifiers as well as for power booster amplifiers. The predicted pump efficiencies (maximum gain to pump...

  10. Amplifying Islam : Pluralism, Secularism, and Religious Sounds in The Netherlands

    NARCIS (Netherlands)

    Tamimi Arab, P.


    This dissertation is an ethnographic study of the amplified azan, the Islamic call to prayer, in the Netherlands, adding a sonic dimension to analyses of the politics of Islamic aesthetics in the western world. Often rejected by opponents as noise pollution, facilitating the amplified azan is an exa

  11. Ferroelectric Field-Effect Transistor Differential Amplifier Circuit Analysis (United States)

    Phillips, Thomas A.; MacLeod, Todd C.; Ho, Fat D.


    There has been considerable research investigating the Ferroelectric Field-Effect Transistor (FeFET) in memory circuits. However, very little research has been performed in applying the FeFET to analog circuits. This paper investigates the use of FeFETs in a common analog circuit, the differential amplifier. The two input Metal-Oxide-Semiconductor (MOS) transistors in a general MOS differential amplifier circuit are replaced with FeFETs. Resistors are used in place of the other three MOS transistors. The FeFET model used in the analysis has been previously reported and was based on experimental device data. Because of the FeFET hysteresis, the FeFET differential amplifier has four different operating modes depending on whether the FeFETs are positively or negatively polarized. The FeFET differential amplifier operation in the different modes was analyzed by calculating the amplifier voltage transfer and gain characteristics shown in figures 2 through 5. Comparisons were made between the FeFET differential amplifier and the standard MOS differential amplifier. Possible applications and benefits of the FeFET differential amplifier are discussed.

  12. Saturation and noise properties of quantum-dot optical amplifiers

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper


    Based on extensive numerical calculations, quantum-dot (QD) amplifiers are predicted to offer higher output power and lower noise figure compared to bulk as well as quantum well amplifiers. The underlying physical mechanisms are analyzed in detail, leading to the identification of a few key...

  13. Energy Efficient and Compact RF High-Power Amplifiers

    NARCIS (Netherlands)

    Calvillo Cortés, D.A.


    The main objectives of this thesis are to improve the energy efficiency and physical form-factor of high-power amplifiers in base station applications. As such, the focus of this dissertation is placed on the outphasing amplifier concept, which can offer high-efficiency, good linearity and excellent

  14. Influence of higher order modes on angled-facet amplifiers

    DEFF Research Database (Denmark)

    Wang, Z.; Mikkelsen, B.; Stubkjær, Kristian


    The influence of the first-order mode on the residual reflectivity of angled-facet amplifiers is analyzed. For a 7 degrees angled-facet ridge waveguide amplifier with a single-layer antireflective (AR) coating, a gain ripple lower than 1-dB at 25-dB gain can be obtained independent...... by increasing the facet angles to 10 degrees...

  15. Design and Analysis of Hybrid CMOS SRAM Sense Amplifier

    Directory of Open Access Journals (Sweden)

    Karishma Bajaj


    Full Text Available Sense amplifiers are one of the very important peripheral components of CMOS memories. In a Hybrid Sense amplifier both current and voltage sensing techniques are used which makes it a better selection than a conventional current or voltage sense amplifiers. The hybrid sense amplifier works in three phases-Offset cancellation (200ps, Access phase (500ps and Evaluation phase. The offset cancellation is done simultaneously with word line decoding, so as to speed up the process. The sensing range of the hybrid sense amplifier is improved from 1.18mV to 92mV. Also hybrid sense amplifier consumes very low energy of about 6.84fj. This sense amplifier is analyzed with a column of 512 SRAM cells at 180nm technology node and compared to CMOS conventional voltage sense amplifier. The circuit consumes an average power of 1.57 µW with a negligible offset of 149.3µV.

  16. External Peltier Cooler For Low-Noise Amplifier (United States)

    Soper, Terry A.


    Inexpensive Peltier-effect cooling module made of few commercially available parts used to reduce thermal noise in microwave amplifier. Retrofitted to almost any microwave low-noise amplifier or receiver preamplifier used in communication, telemetry, or radar. Includes copper or aluminum cold plate held tightly against unit to be cooled by strap-type worm-gear clamps.

  17. An RF Power Amplifier in a Digital CMOS Process

    DEFF Research Database (Denmark)

    Nielsen, Per Asbeck; Fallesen, Carsten


    A two stage class B power amplifier for 1.9 GHz is presented. The amplifier is fabricated in a standard digital EPI-CMOS process with low resistivity substrate. The measured output power is 29 dBm in a 50 Omega load. A design method to find the large signal parameters of the output transistor...

  18. Switching-mode Audio Power Amplifiers with Direct Energy Conversion

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.


    This paper presents a new class of switching-mode audio power amplifiers, which are capable of direct energy conversion from the AC mains to the audio output. They represent an ultimate integration of a switching-mode power supply and a Class D audio power amplifier, where the intermediate DC bus...

  19. Phase Sensitive Amplifier Based on Ultrashort Pump Pulses

    CERN Document Server

    Gershikov, Alexander


    We demonstrate a narrow band phase sensitive amplifier in the pump degenerate configuration which employs ps pump pulses. Control of the amplifier bandwidth is achieved via changes of the pump spectral width. A phase sensitive gain between -6 and 6 decibels, with an overall system gain of 28dB was demonstrated.

  20. Series-Tuned High Efficiency RF-Power Amplifiers

    DEFF Research Database (Denmark)

    Vidkjær, Jens


    An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits.......An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits....

  1. A 300°C Dynamic-Feedback Instrumentation Amplifier

    NARCIS (Netherlands)

    Jong, P.C. de; Meijer, G.C.M.; Roermund, A.H.M. van


    A high-temperature instrumentation amplifier that uses dynamic feedback is presented. It realizes dynamic feedback by means of a rotating chain of resistors to compensate for resistor mismatches. An 11x dynamic-feedback instrumentation amplifier has been integrated in a standard junction-isolated 1.

  2. Implantable neurotechnologies: a review of integrated circuit neural amplifiers. (United States)

    Ng, Kian Ann; Greenwald, Elliot; Xu, Yong Ping; Thakor, Nitish V


    Neural signal recording is critical in modern day neuroscience research and emerging neural prosthesis programs. Neural recording requires the use of precise, low-noise amplifier systems to acquire and condition the weak neural signals that are transduced through electrode interfaces. Neural amplifiers and amplifier-based systems are available commercially or can be designed in-house and fabricated using integrated circuit (IC) technologies, resulting in very large-scale integration or application-specific integrated circuit solutions. IC-based neural amplifiers are now used to acquire untethered/portable neural recordings, as they meet the requirements of a miniaturized form factor, light weight and low power consumption. Furthermore, such miniaturized and low-power IC neural amplifiers are now being used in emerging implantable neural prosthesis technologies. This review focuses on neural amplifier-based devices and is presented in two interrelated parts. First, neural signal recording is reviewed, and practical challenges are highlighted. Current amplifier designs with increased functionality and performance and without penalties in chip size and power are featured. Second, applications of IC-based neural amplifiers in basic science experiments (e.g., cortical studies using animal models), neural prostheses (e.g., brain/nerve machine interfaces) and treatment of neuronal diseases (e.g., DBS for treatment of epilepsy) are highlighted. The review concludes with future outlooks of this technology and important challenges with regard to neural signal amplification.

  3. Slow Light at High Frequencies in an Amplifying Semiconductor Waveguide

    DEFF Research Database (Denmark)

    Öhman, Filip; Yvind, Kresten; Mørk, Jesper


    We demonstrate slow-down of a modulated light signal in a semiconductor waveguide. Concatenated amplifying and absorbing sections simultaneously achieve both amplification and a controllable time delay at 15 GHz.......We demonstrate slow-down of a modulated light signal in a semiconductor waveguide. Concatenated amplifying and absorbing sections simultaneously achieve both amplification and a controllable time delay at 15 GHz....

  4. Coherent Beam Combination of Two Polarization Maintaining Ytterbium Fibre Amplifiers

    Institute of Scientific and Technical Information of China (English)

    HOU Jing; XIAO Rui; JIANG Zong-Fu; CHENG Xiang-Ai; SHU Bai-Hong; CHEN Jin-Bao; LIU Ze-Jin


    @@ We investigate coherent beam combination of fibre laser beams by phase locking. Phase noise of a polarization maintaining ytterbium fibre amplifier is inspected with a fibre interferometer. In a feed back control loop, two fibre polarization maintaining ytterbium amplifiers are phase locked and coherent combined when the phase noise is properly controlled by a LiNO3 phase modulator.

  5. A 24 channel acoustic/vibration test power amplifier (United States)

    Barlett, F. R.


    In the present paper, the advantages and drawbacks of a multichannel amplifier operating in a vibration or acoustic facility are discussed. The configuration of the facility and the multichannel amplifier proposed is a compromise based on the particular requirements and anticipated work load in a specific case under consideration.

  6. Ultrafast Dynamics of Quantum-Dot Semiconductor Optical Amplifiers

    DEFF Research Database (Denmark)

    Poel, Mike van der; Hvam, Jørn Märcher


    We report on a series of experiments on the dynamical properties of quantum-dot semiconductor optical amplifiers. We show how the amplifier responds to one or several ultrafast (170 fs) pulses in rapid succession and our results demonstrate applicability and ultimate limitations to application...

  7. Transesophageal echocardiography, more than a diagnostic tool: use during surgical ligation of coronary artery fistulae - a case report

    Directory of Open Access Journals (Sweden)

    Chung Ping-Chen


    Full Text Available Abstract Coronary artery fistulae (CAF are an infrequent coronary abnormality. Herein, we describe the use of intraoperative transesophageal echocardiography (TEE in the treatment of CAF. A 61 year-old woman presented with chest pain and symptoms consistent with unstable angina. Subsequent coronary angiography revealed the presence of 2 CAF, one extending from the left anterior descending artery to the pulmonary artery (PA and the other extending from the proximal right coronary artery to the PA. Surgical ligation of the CAF without coronary bypass was arranged. Intraoperative TEE was successfully employed to localize the CAF, monitor fistula blood flow and heart wall motion, and confirm successful ligation. The patient recovered without complications. This case highlights the utility of intraoperative TEE during ligation of CAF.

  8. "Bis-Click" Ligation of DNA: Template-Controlled Assembly, Circularisation and Functionalisation with Bifunctional and Trifunctional Azides. (United States)

    Yang, Haozhe; Seela, Frank


    Ligation and circularisation of oligonucleotides containing terminal triple bonds was performed with bifunctional or trifunctional azides. Both reactions are high yielding. Template-assisted bis-click ligation of two individual non-complementary oligonucleotide strands was accomplished to yield heterodimers exclusively. In this context, the template fulfils two functions: it accelerates the ligation reaction and controls product assembly (heterodimer vs. homodimer formation). Intermolecular bis-click circularisation of one oligonucleotide strand took place without template assistance. For construction of oligonucleotides with terminal triple bonds in the nucleobase side chain, 7- or 5-functionalised 7-deaza-dA and dU residues were used. These oligonucleotides are directly accessible by solid-phase synthesis. When trifunctional azides were employed instead of bifunctional linkers, functionalisation of the remaining azido group was performed with small molecules such as 1-ethynyl pyrene, biotin propargyl amide or with ethynylated oligonucleotides. By this means, branched DNA was constructed.

  9. Fishing amplifies forage fish population collapses. (United States)

    Essington, Timothy E; Moriarty, Pamela E; Froehlich, Halley E; Hodgson, Emma E; Koehn, Laura E; Oken, Kiva L; Siple, Margaret C; Stawitz, Christine C


    Forage fish support the largest fisheries in the world but also play key roles in marine food webs by transferring energy from plankton to upper trophic-level predators, such as large fish, seabirds, and marine mammals. Fishing can, thereby, have far reaching consequences on marine food webs unless safeguards are in place to avoid depleting forage fish to dangerously low levels, where dependent predators are most vulnerable. However, disentangling the contributions of fishing vs. natural processes on population dynamics has been difficult because of the sensitivity of these stocks to environmental conditions. Here, we overcome this difficulty by collating population time series for forage fish populations that account for nearly two-thirds of global catch of forage fish to identify the fingerprint of fisheries on their population dynamics. Forage fish population collapses shared a set of common and unique characteristics: high fishing pressure for several years before collapse, a sharp drop in natural population productivity, and a lagged response to reduce fishing pressure. Lagged response to natural productivity declines can sharply amplify the magnitude of naturally occurring population fluctuations. Finally, we show that the magnitude and frequency of collapses are greater than expected from natural productivity characteristics and therefore, likely attributed to fishing. The durations of collapses, however, were not different from those expected based on natural productivity shifts. A risk-based management scheme that reduces fishing when populations become scarce would protect forage fish and their predators from collapse with little effect on long-term average catches.

  10. Chemically amplified resist modeling in OPC (United States)

    Zheng, Xin; Huang, Jason; Kuo, Fred; Kazarian, Aram; Chin, Fook; Fan, Yongfa


    The mechanism of chemically amplified resist plays a critical role in the modeling of the latent image. To achieve a practical model which can fit into the time frame of OPC, some simplifications and assumptions have to be made. We introduced regression kernels that take into account best exposure focus difference between isotropic pitch, dense, and line end features for the evaluation of image intensity. It compares the image intensity (signal) over small changes above and/or below the regressed "nominal" image position, which in principle corresponds to evaluating the intensity signal at various depths of a fixed resist profile thus can also be regressed for optimization during model development. Our calibration has shown that the model brought a great improvement in prediction for difficult structures such as dense features at or near the optical resolution limit and 2-dimensional features, which are the limiter of the overall model fitting accuracy for 45nm node and below. By replacing other existing techniques, total number of output kernels used for OPC operation is actually reduced with improvement of model accuracy. This model is proven to be a very effective yet accurate addition to the current OPC technology.

  11. Gold Nanoparticle Labels Amplify Ellipsometric Signals (United States)

    Venkatasubbarao, Srivatsa


    The ellipsometric method reported in the immediately preceding article was developed in conjunction with a method of using gold nanoparticles as labels on biomolecules that one seeks to detect. The purpose of the labeling is to exploit the optical properties of the gold nanoparticles in order to amplify the measurable ellipsometric effects and thereby to enable ultrasensitive detection of the labeled biomolecules without need to develop more-complex ellipsometric instrumentation. The colorimetric, polarization, light-scattering, and other optical properties of nanoparticles depend on their sizes and shapes. In the present method, these size-and-shape-dependent properties are used to magnify the polarization of scattered light and the diattenuation and retardance of signals derived from ellipsometry. The size-and-shape-dependent optical properties of the nanoparticles make it possible to interrogate the nanoparticles by use of light of various wavelengths, as appropriate, to optimally detect particles of a specific type at high sensitivity. Hence, by incorporating gold nanoparticles bound to biomolecules as primary or secondary labels, the performance of ellipsometry as a means of detecting the biomolecules can be improved. The use of gold nanoparticles as labels in ellipsometry has been found to afford sensitivity that equals or exceeds the sensitivity achieved by use of fluorescence-based methods. Potential applications for ellipsometric detection of gold nanoparticle-labeled biomolecules include monitoring molecules of interest in biological samples, in-vitro diagnostics, process monitoring, general environmental monitoring, and detection of biohazards.

  12. Efficient and Compact Optical Amplifier Using EYDF

    Directory of Open Access Journals (Sweden)

    Sulaiman Wadi Harun


    Full Text Available An efficient Erbium/Ytterbium doped fiber amplifier (EYDFA is demonstrated using a 1058nm pumping wavelength, where the amplification is assisted by energy transfer between Yb and Er ions. The energy transfer increases the limit of erbium doping concentration that is imposed by concentration quenching in Erbium-doped fiber (EDF. Therefore, the gain and noise figure are severely degraded with 1480 nm pumping, where the energy transfer cannot be achieved. The use of optical isolator improves the small signal gain and noise figure by about 4.8 dB and 1.6 dB, respectively. By employing a double-pass configuration, a higher gain can be obtained with an expense of a noise figure penalty. The gain improvement of 17.0 dB is obtained at 20 mW and -50 dBm of pump and input signal powers. This shows that the double-pass configuration is an important aspect to consider when designing an efficient EYDFA.

  13. Globalization to amplify economic climate losses (United States)

    Otto, C.; Wenz, L.; Levermann, A.


    Economic welfare under enhanced anthropogenic carbon emissions and associated future warming poses a major challenge for a society with an evolving globally connected economy. Unabated climate change will impact economic output for example through heat-stress-related reductions in productivity. Since meteorologically-induced production reductions can propagate along supply chains, structural changes in the economic network may influence climate-related losses. The role of the economic network evolution for climate impacts has been neither quantified nor qualitatively understood. Here we show that since the beginning of the 21st century the structural change of the global supply network has been such that an increase of spillover losses due to unanticipated climatic events has to be expected. We quantify primary, secondary and higher-order losses from reduced labor productivity under past and present economic and climatic conditions and find that indirect losses are significant and increase with rising temperatures. The connectivity of the economic network has increased in such a way as to foster the propagation of production loss. This supply chain connectivity robustly exhibits the characteristic distribution of self-organized criticality which has been shifted towards higher values since 2001. Losses due to this structural evolution dominated over the effect of comparably weak climatic changes during this decade. Our finding suggests that the current form of globalization may amplify losses due to climatic extremes and thus necessitate structural adaptation that requires more foresight than presently prevalent.

  14. Single Ion Quantum Lock-In Amplifier

    CERN Document Server

    Kotler, Shlomi; Glickman, Yinnon; Keselman, Anna; Ozeri, Roee


    We report on the implementation of a quantum analog to the classical lock-in amplifier. All the lock-in operations: modulation, detection and mixing, are performed via the application of non-commuting quantum operators on the electronic spin state of a single trapped Sr+ ion. We significantly increase its sensitivity to external fields while extending phase coherence by three orders of magnitude, to more than one second. With this technique we measure magnetic fields with sensitivity of 25 pT/sqrt(Hz) and light shifts with an uncertainty below 140 mHz after 1320 seconds of averaging. These sensitivities are limited by quantum projection noise and, to our knowledge, are more than two orders of magnitude better than with other single-spin probe technologies. In fact, our reported sensitivity is sufficient for the measurement of parity non-conservation, as well as the detection of the magnetic field of a single electronic-spin one micrometer from an ion-detector with nanometer resolution. As a first application ...

  15. Status Report on the Energy Amplifier

    CERN Document Server

    Rubbia, Carlo


    0ne year after its first presentation,the Energy Amplifier (EA) Project holds its promises for a environmentally acceptable form of energy extraction from nuclei, namely to eliminate or at least greatly reduce(i) the environmental impact of the long-lived highly radioactive waste;(ii) the possibility of diversions toward military applications;(iii) the risks of an accidental divergence related to the critical operation of the chain reaction and (iv) make a more efficient use of a fuel which is less radio-toxic to extract and more abundant on Earth than Uranium. In these respects the EA (or equivalent scenarios from Los Alamos and elsewhere) is comparable in performance to Thermonuclear Fusion. Bot h approches offer pratically unl;imited fuel resources: the energetic content of Lithium on the Earth's crust needed by Fusion is estimated to be seven times the one of Thorium and they are both adequate for millions of years of very intensived utilisation.However the EA can be built economically,in a variety of siz...

  16. Pulse laser imaging amplifier for advanced ladar systems (United States)

    Khizhnyak, Anatoliy; Markov, Vladimir; Tomov, Ivan; Murrell, David


    Security measures sometimes require persistent surveillance of government, military and public areas Borders, bridges, sport arenas, airports and others are often surveilled with low-cost cameras. Their low-light performance can be enhanced with laser illuminators; however various operational scenarios may require a low-intensity laser illumination with the object-scattered light intensity lower than the sensitivity of the Ladar image detector. This paper discusses a novel type of high-gain optical image amplifier. The approach enables time-synchronization of the incoming and amplifying signals with accuracy <= 1 ns. The technique allows the incoming signal to be amplified without the need to match the input spectrum to the cavity modes. Instead, the incoming signal is accepted within the spectral band of the amplifier. We have gauged experimentally the performance of the amplifier with a 40 dB gain and an angle of view 20 mrad.

  17. GHz bandwidth noise eater hybrid optical amplifier: design guidelines. (United States)

    Danion, Gwennaël; Bondu, François; Loas, Goulc'hen; Alouini, Mehdi


    This Letter describes the design of an optical amplifier system optimized to reduce the relative intensity noise (RIN) of the input signal, and discloses its performance in terms of intensity noise reduction and bandwidth, without phase noise degradation. This polarization-maintaining amplifier is composed of an erbium-doped fiber amplifier (EDFA) cascaded with a semiconductor optical amplifier (SOA). The EDFA is sized to feed the SOA with a constant power corresponding to the optimal saturation level for noise reduction, through coherent population oscillations. When properly optimized, such an amplifier provides, simultaneously, 17 dB optical gain, 5.4 dB noise factor, and 20 dB reduction of the input-RIN across a 3 GHz bandwidth, without any electronics feedback loop.

  18. Quantum Dot Semiconductor Optical Amplifiers - Physics and Applications

    DEFF Research Database (Denmark)

    Berg, Tommy Winther


    This thesis describes the physics and applications of quantum dot semiconductor optical amplifiers based on numerical simulations. These devices possess a number of unique properties compared with other types of semiconductor amplifiers, which should allow enhanced performance of semiconductor...... respects is comparable to those of fiber amplifiers. The possibility of inverting the optically active states to a large degree is essential in order to achieve this performance. Optical signal processing through cross gain modulation and four wave mixing is modeled and described. For both approaches...... and QW devices and to experiments on quantum dot amplifiers. These comparisons outline the qualitative differences between the different types of amplifiers. In all cases focus is put on the physical processes responsible the differences....

  19. A Review of High Voltage Drive Amplifiers for Capacitive Actuators

    DEFF Research Database (Denmark)

    Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.


    This paper gives an overview of the high voltage amplifiers, which are used to drive capacitive actuators. The amplifiers for both piezoelectric and DEAP (dielectric electroactive polymer) actuator are discussed. The suitable topologies for driving capacitive actuators are illustrated in detail, ......, including linear as well as switched mode amplifiers. In the past much attention has been paid on the driver for piezoelectric actuator. As DEAP is a type of new material, there is not much literature reference for it.......This paper gives an overview of the high voltage amplifiers, which are used to drive capacitive actuators. The amplifiers for both piezoelectric and DEAP (dielectric electroactive polymer) actuator are discussed. The suitable topologies for driving capacitive actuators are illustrated in detail...

  20. Digital Lock-in Amplifier Based on Microcontroller

    Institute of Scientific and Technical Information of China (English)

    An-li TAO; Guo-dong XU; Ke-xue LUO; Gang-ling ZHANG


    A method of implementing high cost-effective and highly integrated digital lock-in amplifier with microcontroller is discussed. And the digital lock-in amplifier is more suitable for measuring low-frequency weak signal.Digital signal sequence is obtained through sampling signal measured over an integer number of signal periods, but digital reference sequence is acquired through mathematical operation, then digital phase sensitive detection can be implemented by calculating the cross-correlation function of digital signal sequence and digital reference sequence.In addition, the frequency response and phase character of the digital lock-in amplifier is analyzed. Finally, the designed digital lock-in amplifier is achieved. Experimental results show that the digital lock-in amplifier can be used for measuring weak signal with low ignal-to-noise ratio.