Science.gov

Sample records for alis-flp amplified ligation

  1. A ligation-triggered DNAzyme cascade for amplified fluorescence detection of biological small molecules with zero-background signal.

    PubMed

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

    2011-08-03

    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.

  2. Highly sensitive and selective chemiluminescent imaging for DNA detection by ligation-mediated rolling circle amplified synthesis of DNAzyme.

    PubMed

    Dong, Haifeng; Wang, Chen; Xiong, Yi; Lu, Huiting; Ju, Huangxian; Zhang, Xueji

    2013-03-15

    A highly sensitive DNA biosensing method down to sub-femtomolar level with excellent selectivity was proposed by designing an amplified synthesis of horseradish peroxidase mimicking DNAzyme and introducing the amplified DNAzyme to chemiluminescent (CL) imaging. The amplified synthesis was achieved by combining a target DNA related ligase reaction with rolling circle amplification (RCA), which produced thousands of repeated sequences to bind hemin and form a mass of horseradish peroxidase-mimicing DNAzyme units. The amplification strategy greatly enhanced the CL emission of the luminol-H(2)O(2) system. The genotyping method displayed highly specific biochemistry in allele discrimination. The novel CL imaging strategy based on ligation-mediated RCA synthesis of DNAzyme showed high fidelity in discriminating single-base mismatch and efficiently facilitated signal amplification for sensitive target DNA detection. It could detect DNA ranging from 1×10(-15) M to 1×10(-11) M with a detection limit of 0.26 fM. The proposed approach provided a robust, cost-efficient, highly sensitive and specific platform for genetic target analysis in bioanalysis and clinic biomedical application. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Tubal ligation

    MedlinePlus

    ... tying; Tying the tubes; Hysteroscopic tubal occlusion procedure; Contraception - tubal ligation; Family planning - tubal ligation ... Tubal ligation is considered a permanent form of birth control. It is NOT recommended as a short-term ...

  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.

    PubMed

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

    2015-01-15

    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. Tubal Ligation

    MedlinePlus

    ... The insert causes scar tissue to form and seal off the tubes. Tubal ligation is an abdominal ... instruments passed through the abdominal wall, your doctor seals the fallopian tubes by destroying segments of the ...

  6. Ligation-based assembly for constructing mouse synthetic scFv libraries by chain shuffling with in vivo-amplified VH and VL fragments.

    PubMed

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

    2014-10-01

    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

  7. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn Ruth

    2011-12-13

    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

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn

    2006-10-17

    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

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn Ruth

    2010-11-23

    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

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn

    2003-05-27

    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

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn R.

    2010-02-23

    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

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn R.

    2011-04-12

    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. Chemoselective ligation

    DOEpatents

    Saxon, Eliana; Bertozzi, Carolyn R.

    2011-05-10

    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).

  14. Clinical application of a ligation-independent pathway of multiplex ligation-dependent probe amplification for the determination of quinolone susceptibility of Streptococcus pneumoniae.

    PubMed

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

    2016-09-01

    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. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Tubal ligation - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100044.htm Tubal ligation - Series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 3 Go to slide 2 ...

  16. PULSE AMPLIFIER

    DOEpatents

    Johnstone, C.W.

    1958-06-17

    The improvement of pulse amplifiers used with scintillation detectors is described. The pulse amplifier circuit has the advantage of reducing the harmful effects of overloading cause by large signal inputs. In general the pulse amplifier circuit comprises two amplifier tubes with the input pulses applied to one amplifier grid and coupled to the second amplifier tube through a common cathode load. The output of the second amplifier is coupled from the plate circuit to a cathode follower tube grid and a diode tube in connected from grid to cathode of the cathode follower tube. Degenerative feedback is provided in the second amplifier by coupling a signal from the cathode follower cathode to the second amplifier grid. The circuit proqides moderate gain stability, and overload protection for subsequent pulse circuits.

  17. Electronic amplifiers: A compilation

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Several types of amplifiers and amplifier systems are considered. These include preamplifiers, high power amplifiers, buffer and isolation amplifiers, amplifier circuits, and general purpose amplifiers.

  18. Self ligating lingual appliance

    PubMed Central

    Juneja, Pankaj; Chopra, S.S.; Jayan, B.K.

    2015-01-01

    Adult demand for orthodontics has grown considerably over the past 10 years propelling increased demand for Esthetic Orthodontics. Lingual appliances are a viable option toward providing Esthetic Orthodontics. The lingual surface of the teeth has a unique morphology that makes it difficult to place brackets in ideal positions. Indirect bonding has become the established methods of overcoming these discrepancies, along with the latest designs of self ligating brackets which offer more efficient mechanics and shorter treatment time. PMID:26843757

  19. Precise Sequential DNA Ligation on A Solid Substrate: Solid-Based Rapid Sequential Ligation of Multiple DNA Molecules

    PubMed Central

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

    2013-01-01

    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. PMID:23897972

  20. Oestrogen deficiency after tubal ligation.

    PubMed

    Cattanach, J

    1985-04-13

    4 of 7 women who had undergone tubal ligation within the past seven years were found to have oestrogen excretion concentrations at ovulation below the tenth percentile. A disturbance in the oestrogen/progesterone ratio as a consequence of localised hypertension at the ovary, when the utero-ovarian arterial loop is occluded at tubal ligation, is proposed as a possible cause of oestrogen deficiency syndrome, dysfunctional uterine bleeding, and menorrhagia after tubal ligation. Similar pathophysiology may occur after hysterectomy with ovarian conservation.

  1. LOGARITHMIC AMPLIFIER

    DOEpatents

    De Shong, J.A. Jr.

    1957-12-31

    A logarithmic current amplifier circuit having a high sensitivity and fast response is described. The inventor discovered the time constant of the input circuit of a system utilizing a feedback amplifier, ionization chamber, and a diode, is inversely proportional to the input current, and that the amplifier becomes unstable in amplifying signals in the upper frequency range when the amplifier's forward gain time constant equals the input circuit time constant. The described device incorporates impedance networks having low frequency response characteristic at various points in the circuit to change the forward gain of the amplifler at a rate of 0.7 of the gain magnitude for every two times increased in frequency. As a result of this improvement, the time constant of the input circuit is greatly reduced at high frequencies, and the amplifier response is increased.

  2. Operational Amplifiers.

    ERIC Educational Resources Information Center

    Foxcroft, G. E.

    1986-01-01

    Addresses the introduction of low cost equipment into high school and college physical science classes. Examines the properties of an "ideal" operational amplifier and discusses how it might be used under saturated and non-saturated conditions. Notes the action of a "real" operational amplifier. (TW)

  3. Operational Amplifiers.

    ERIC Educational Resources Information Center

    Foxcroft, G. E.

    1986-01-01

    Addresses the introduction of low cost equipment into high school and college physical science classes. Examines the properties of an "ideal" operational amplifier and discusses how it might be used under saturated and non-saturated conditions. Notes the action of a "real" operational amplifier. (TW)

  4. Amplifier Distortion

    NASA Astrophysics Data System (ADS)

    Keeports, David

    2006-12-01

    By definition, a high fidelity amplifier's instantaneous output voltage is directly proportional to its instantaneous input voltage. While high fidelity is generally valued in the amplification of recorded music, nonlinearity, also known as distortion, is desirable in the amplification of some musical instruments. In particular, guitar amplifiers exploit nonlinearity to increase both the harmonic content and sustain of a guitar's sound. I will discuss how both modifications in sound result from saturation of triode tubes and transistors. Additionally, I will describe the difference in the symmetry of saturation curves for transistors and tubes and the reason why tube guitar amplifiers are generally considered to be superior to solid-state amplifiers. Finally, I will discuss attempts to use solid-state electronics to replicate the sound of tube amplifiers.

  5. LOGARITHMIC AMPLIFIER

    DOEpatents

    Wade, E.J.; Stone, R.S.

    1959-03-10

    Electronic,amplifier circuits, especially a logai-ithmic amplifier characterizxed by its greatly improved strability are discussed. According to the in ention, means are provided to feed bach the output valtagee to a diode in the amplifier input circuit, the diode being utilized to produce the logarithmic characteristics. The diode is tics, The diode isition therewith and having its filament operated from thc same source s the filament of the logarithmic diode. A bias current of relatively large value compareii with the signal current is continuously passed through the compiting dioie to render the diode insensitivy to variations in the signal current. by this odes kdu to variaelled, so that the stability of the amlifier will be unimpaired.

  6. Bidirectional amplifier

    DOEpatents

    Wright, James T.

    1986-01-01

    A bilateral circuit is operable for transmitting signals in two directions without generation of ringing due to feedback caused by the insertion of the circuit. The circuit may include gain for each of the signals to provide a bidirectional amplifier. The signals are passed through two separate paths, with a unidirectional amplifier in each path. A controlled sampling device is provided in each path for sampling the two signals. Any feedback loop between the two signals is disrupted by providing a phase displacement between the control signals for the two sampling devices.

  7. Bidirectional amplifier

    DOEpatents

    Wright, J.T.

    1984-02-02

    A bilateral circuit is operable for transmitting signals in two directions without generation of ringing due to feedback caused by the insertion of the circuit. The circuit may include gain for each of the signals to provide a bidirectional amplifier. The signals are passed through two separate paths, with a unidirectional amplifier in each path. A controlled sampling device is provided in each path for sampling the two signals. Any feedback loop between the two signals is disrupted by providing a phase displacement between the control signals for the two sampling devices.

  8. Amplified Policymaking

    ERIC Educational Resources Information Center

    Prince, Katherine; Woempner, Carolyn

    2010-01-01

    This brief examines the policy implications of two drivers of change presented in the "2020 Forecast: Creating the Future of Learning"-- Pattern Recognition and Amplified Organization. These drivers point toward a series of cultural shifts and illuminate how we are developing new ways of organizing, constructing, and managing knowledge.…

  9. Tetrazine ligation for chemical proteomics.

    PubMed

    Kang, Kyungtae; Park, Jongmin; Kim, Eunha

    2016-01-01

    Determining small molecule-target protein interaction is essential for the chemical proteomics. One of the most important keys to explore biological system in chemical proteomics field is finding first-class molecular tools. Chemical probes can provide great spatiotemporal control to elucidate biological functions of proteins as well as for interrogating biological pathways. The invention of bioorthogonal chemistry has revolutionized the field of chemical biology by providing superior chemical tools and has been widely used for investigating the dynamics and function of biomolecules in live condition. Among 20 different bioorthogonal reactions, tetrazine ligation has been spotlighted as the most advanced bioorthogonal chemistry because of their extremely faster kinetics and higher specificity than others. Therefore, tetrazine ligation has a tremendous potential to enhance the proteomic research. This review highlights the current status of tetrazine ligation reaction as a molecular tool for the chemical proteomics.

  10. [Post-tubal ligation syndrome].

    PubMed

    Satoh, K; Osada, H

    1993-01-01

    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.

  11. The postal tubal ligation syndrome.

    PubMed

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

    1981-01-01

    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

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

    PubMed

    Ujhelyi, Gabriella; Dijk, Jeroen P van; Prins, Theo W; Voorhuijzen, Marleen M; Hoef, A M Angeline Van; Beenen, Henriek G; Morisset, Dany; Gruden, Kristina; Kok, Esther J

    2012-01-19

    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. 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). 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 interlaboratory exchange study it was shown that the selected

  13. [Latex ligation in treatment of chronic hemorrhoids].

    PubMed

    Ektov, V N; Somov, K A

    2015-01-01

    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.

  14. A novel, one-step amplification and oligonucleotide ligation procedure for multiplex genetic typing

    SciTech Connect

    Eggerding, F.A.

    1994-09-01

    A new technique, coupled amplification and oligonucleotide ligation (CAL), has been developed for simultaneous multiplex amplification and genotyping of DNA. CAL is a biphasic method which combines in one assay DNA amplification by the polymerase chain reaction (PCR) with DNA genotyping by the oligonucleotide ligation assay (OLA). By virtue of a difference in the melting temperatures of PCR primer-target DNA and OLA probe-target DNA hybrids, the method allows preferential amplification of DNA during stage I and oligonucleotide ligation during stage II of the reaction. In stage I target DNA is amplified using high-melting primers in a two-step PCR cycle that employs a 72{degrees}C anneal-elongation step. In stage II genotyping of PCR products by competitive oligonucleotide ligation with oligonucleotide probes located between PCR primers is accomplished by several cycles of denaturation at 94{degrees}C followed by anneal-ligation at 55{degrees}C. Ligation products are fluorochrome-labeled at their 3{prime}-ends and analyzed electrophoretically on a fluorescent DNA sequencer. The CAL procedure has been used for multiplex detection of 30 cystic fibrosis mutations and for analysis of ras gene point mutations. Because mutation detection occurs concurrently with target amplification, the technique is rapid, highly sensitive and specific, easily automatable, and requires minimal sample processing.

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

    SciTech Connect

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

    2008-05-27

    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.

  16. Fluorescent amplified fragment length polymorphism (fAFLP) analysis of Listeria monocytogenes.

    PubMed

    Amar, Corinne

    2014-01-01

    Fluorescent amplified fragment length polymorphism (fAFLP) is based on the selective PCR amplification of restriction fragments from a digest of total genomic DNA. Genomic DNA extracted from a purified bacterial isolate is completely digested with two endonucleases generating fragments which are ligated to specific double-stranded adaptors. The ligated fragments are then amplified by PCR using fluorescently labelled primers. Fluorescent amplified fragments are separated by size on an automated sequencer with a size standard. fAFLP is a rapid, highly reproducible technique which can be used to discriminate and subtype Listeria monocytogenes strains.

  17. Low cost instrumentation amplifier

    NASA Technical Reports Server (NTRS)

    Sturman, J. C.

    1974-01-01

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

  18. Determinants of tubal ligation in Puebla, Mexico.

    PubMed

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

    2011-06-21

    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.

  19. The "Floss-Ligature" Ligation Technique.

    PubMed

    Dugdale, Charlotte Anne; Malik, Ovais Humair; Waring, David Trevor

    2015-01-01

    This clinical pearl describes an alternative technique to aid effective ligation of rotated teeth during the aligning stage of fixed appliance treatment. This technique has the potential to improve patient experience and confidence, by reducing the risk of trauma and discomfort and treatment efficiency, by ensuring complete ligation of even severely rotated teeth.

  20. 21 CFR 876.4400 - Hemorrhoidal ligator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hemorrhoidal ligator. 876.4400 Section 876.4400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4400 Hemorrhoidal ligator. (a...

  1. 21 CFR 876.4400 - Hemorrhoidal ligator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hemorrhoidal ligator. 876.4400 Section 876.4400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4400 Hemorrhoidal ligator. (a...

  2. SQUARE WAVE AMPLIFIER

    DOEpatents

    Leavitt, M.A.; Lutz, I.C.

    1958-08-01

    An amplifier circuit is described for amplifying sigmals having an alternating current component superimposed upon a direct current component, without loss of any segnnent of the alternating current component. The general circuit arrangement includes a vibrator, two square wave amplifiers, and recombination means. The amplifier input is connected to the vibrating element of the vibrator and is thereby alternately applied to the input of each square wave amplifier. The detailed circuitry of the recombination means constitutes the novelty of the annplifier and consists of a separate, dual triode amplifier coupled to the output of each square wave amplifier with a recombination connection from the plate of one amplifier section to a grid of one section of the other amplifier. The recombination circuit has provisions for correcting distortion caused by overlapping of the two square wave voltages from the square wave amplifiers.

  3. Segmented amplifier configurations for laser amplifier

    DOEpatents

    Hagen, Wilhelm F.

    1979-01-01

    An amplifier system for high power lasers, the system comprising a compact array of segments which (1) preserves high, large signal gain with improved pumping efficiency and (2) allows the total amplifier length to be shortened by as much as one order of magnitude. The system uses a three dimensional array of segments, with the plane of each segment being oriented at substantially the amplifier medium Brewster angle relative to the incident laser beam and with one or more linear arrays of flashlamps positioned between adjacent rows of amplifier segments, with the plane of the linear array of flashlamps being substantially parallel to the beam propagation direction.

  4. Neurodevelopmental outcomes following two different treatment approaches (early ligation and selective ligation) for patent ductus arteriosus.

    PubMed

    Wickremasinghe, Andrea C; Rogers, Elizabeth E; Piecuch, Robert E; Johnson, Bridget C; Golden, Suzanne; Moon-Grady, Anita J; Clyman, Ronald I

    2012-12-01

    To examine whether a change in the approach to managing persistent patent ductus arteriosus (PDA) from early ligation to selective ligation is associated with an increased risk of abnormal neurodevelopmental outcomes. In 2005, we changed our PDA treatment protocol for infants born at ≤27 6/7 weeks' gestation from an early ligation approach, with prompt PDA ligation if the ductus failed to close after indomethacin therapy (period 1: January 1999 to December 2004), to a selective ligation approach, with PDA ligation performed only if specific criteria were met (period 2: January 2005 to May 2009). All infants in both periods received prophylactic indomethacin. Multivariate analysis was used to compare the odds of a composite abnormal neurodevelopmental outcome (Bayley Mental Developmental Index or Cognitive Score <70, cerebral palsy, blindness, and/or deafness) associated with each treatment approach at age 18-36 months (n = 224). During period 1, 23% of the infants in follow-up failed indomethacin treatment, and all underwent surgical ligation. During period 2, 30% of infants failed indomethacin, and 66% underwent ligation after meeting prespecified criteria. Infants treated with the selective ligation strategy demonstrated fewer abnormal outcomes than those treated with the early ligation approach (OR, 0.07; P = .046). Infants who underwent ligation before 10 days of age had an increased incidence of abnormal neurodevelopmental outcome. The significant difference in outcomes between the 2 PDA treatment strategies could be accounted for in part by the earlier age of ligation during period 1. A selective ligation approach for PDAs that fail to close with indomethacin therapy is not associated with worse neurodevelopmental outcomes at age 18-36 months. Copyright © 2012 Mosby, Inc. All rights reserved.

  5. Cloning of DNA fragments: ligation reactions in agarose gel.

    PubMed

    Furtado, Agnelo

    2014-01-01

    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.

  6. Hybrid matrix amplifier

    DOEpatents

    Martens, Jon S.; Hietala, Vincent M.; Plut, Thomas A.

    1995-01-01

    The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N.times.M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise.

  7. Cross-differential amplifier

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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.

  8. Cross-differential amplifier

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

  9. Cross-differential amplifier

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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.

  10. Cross-differential amplifier

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    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.

  11. Hybrid matrix amplifier

    DOEpatents

    Martens, J.S.; Hietala, V.M.; Plut, T.A.

    1995-01-03

    The present invention comprises a novel matrix amplifier. The matrix amplifier includes an active superconducting power divider (ASPD) having N output ports; N distributed amplifiers each operatively connected to one of the N output ports of the ASPD; and a power combiner having N input ports each operatively connected to one of the N distributed amplifiers. The distributed amplifier can included M stages of amplification by cascading superconducting active devices. The power combiner can include N active elements. The resulting (N[times]M) matrix amplifier can produce signals of high output power, large bandwidth, and low noise. 6 figures.

  12. Heterotopic Pregnancy Following Reversal of Tubal Ligation.

    PubMed

    Eschenbach, Stephanie; Entzian, Dirk; Baumgarten, Deborah A

    2008-01-01

    We describe the case of a 37-year-old woman who had undergone reversal of tubal ligation with subsequent heterotopic pregnancy. We review the initial radiological evaluation of heterotopic pregnancies and the subsequent radiologic findings following appropriate therapy.

  13. Portable musical instrument amplifier

    SciTech Connect

    Christian, David E.

    1990-07-24

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

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

    PubMed Central

    2012-01-01

    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 interlaboratory exchange study it

  15. Laser amplifier chain

    DOEpatents

    Hackel, Richard P.

    1992-01-01

    A laser amplifier chain has a plurality of laser amplifiers arranged in a chain to sequentially amplify a low-power signal beam to produce a significantly higher-power output beam. Overall efficiency of such a chain is improved if high-gain, low efficiency amplifiers are placed on the upstream side of the chain where only a very small fraction of the total pumped power is received by the chain and low-gain, high-efficiency amplifiers are placed on the downstream side where a majority of pumping energy is received by the chain.

  16. Laser amplifier chain

    DOEpatents

    Hackel, R.P.

    1992-10-20

    A laser amplifier chain has a plurality of laser amplifiers arranged in a chain to sequentially amplify a low-power signal beam to produce a significantly higher-power output beam. Overall efficiency of such a chain is improved if high-gain, low efficiency amplifiers are placed on the upstream side of the chain where only a very small fraction of the total pumped power is received by the chain and low-gain, high-efficiency amplifiers are placed on the downstream side where a majority of pumping energy is received by the chain. 6 figs.

  17. Ultrasensitive detection of DNA and RNA based on enzyme-free click chemical ligation chain reaction on dispersed gold nanoparticles.

    PubMed

    Kato, Daiki; Oishi, Motoi

    2014-10-28

    An ultrasensitive colorimetric DNA and RNA assay using a combination of enzyme-free click chemical ligation chain reaction (CCLCR) on dispersed gold nanoparticles (GNPs) and a magnetic separation process has been developed. The click chemical ligation between an azide-containing probe DNA-modified GNP and a dibenzocyclooctyne-containing probe biotinyl DNA occurred through hybridization with target DNA (RNA) to form the biotinyl-ligated GNPs (ligated products). Eventually, both the biotinyl-ligated GNPs and target DNA (RNA) were amplified exponentially using thermal cycling. After separation of the biotinyl-ligated GNPs using streptavidin-modified magnetic beads, the change in intensity of the surface plasmon band at 525 nm in the supernatants was observed by UV/vis measurement and was also evident visually. The CCLCR assay provides ultrasensitive detection (50 zM: several copies) of target DNA that is comparable to PCR-based approaches. Note that target RNA could also be detected with similar sensitivity without the need for reverse transcription to the corresponding cDNA. The amplification efficiency of the CCLCR assay was as high as 82% due to the pseudohomogeneous reaction behavior of CCLCR on dispersed GNPs. In addition, the CCLCR assay was able to discriminate differences in single-base mismatches and to specifically detect target DNA and target RNA from the cell lysate.

  18. Single universal primer multiplex ligation-dependent probe amplification with sequencing gel electrophoresis analysis.

    PubMed

    Shang, Ying; Zhu, Pengyu; Xu, Wentao; Guo, Tianxiao; Tian, Wenying; Luo, Yunbo; Huang, Kunlun

    2013-12-15

    In this study, a novel single universal primer multiplex ligation-dependent probe amplification (SUP-MLPA) technique that uses only one universal primer to perform multiplex polymerase chain reaction (PCR) was developed. Two reversely complementary common sequences were designed on the 5' or 3' end of the ligation probes (LPs), which allowed the ligation products to be amplified through only a single universal primer (SUP). SUP-MLPA products were analyzed on sequencing gel electrophoresis with extraordinary resolution. This method avoided the high expenses associated with capillary electrophoresis, which was the commonly used detection instrument. In comparison with conventional multiplex PCR, which suffers from low sensitivity, nonspecificity, and amplification disparity, SUP-MLPA had higher specificity and sensitivity and a low detection limit of 0.1 ng for detecting single crop species when screening the presence of genetically modified crops. We also studied the effect of different lengths of stuffer sequences on the probes for the first time. Through comparing the results of quantitative PCR, the LPs with different stuffer sequences did not affect the ligation efficiency, which further increased the multiplicity of this assay. The improved SUP-MLPA and sequencing gel electrophoresis method will be useful for food and animal feed identification, bacterial detection, and verification of genetic modification status of crops.

  19. Wireless Josephson amplifier

    SciTech Connect

    Narla, A.; Sliwa, K. M.; Hatridge, M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H.

    2014-06-09

    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.

  20. Wireless Josephson amplifier

    NASA Astrophysics Data System (ADS)

    Narla, A.; Sliwa, K. M.; Hatridge, M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H.

    2014-06-01

    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.

  1. Tubal ligation and risk of breast cancer

    PubMed Central

    Brinton, L A; Gammon, M D; Coates, R J; Hoover, R N

    2000-01-01

    Although it has been demonstrated in previous studies that tubal ligation can have widespread effects on ovarian function, including a decrease in the risk of subsequent ovarian cancer, few studies have evaluated effects on breast cancer risk. In a population-based case–control study of breast cancer among women 20–54 years of age conducted in three geographic areas, previous tubal ligations were reported by 25.3% of the 2173 cases and 25.8% of the 1990 controls. Initially it appeared that tubal ligations might impart a slight reduction in risk, particularly among women undergoing the procedure at young ages (< 25 years). However, women were more likely to have had the procedure if they were black, less educated, young when they bore their first child, or multiparous. After accounting for these factors, tubal ligations were unrelated to breast cancer risk (relative risk (RR) = 1.09, 95% confidence interval (CI) 0.9–1.3), with no variation in risk by age at, interval since, or calendar year of the procedure. The relationship of tubal ligations to risk did not vary according to the presence of a number of other risk factors, including menopausal status or screening history. Furthermore, effects of tubal ligation were similar for all stages at breast cancer diagnosis. Further studies would be worthwhile given the biologic plausibility of an association. However, future investigations should include information on type of procedure performed (since this may relate to biologic effects) as well as other breast cancer risk factors. © 2000 Cancer Research Campaign PMID:10789731

  2. Compact laser amplifier system

    DOEpatents

    Carr, R.B.

    1974-02-26

    A compact laser amplifier system is described in which a plurality of face-pumped annular disks, aligned along a common axis, independently radially amplify a stimulating light pulse. Partially reflective or lasing means, coaxially positioned at the center of each annualar disk, radially deflects a stimulating light directed down the common axis uniformly into each disk for amplification, such that the light is amplified by the disks in a parallel manner. Circumferential reflecting means coaxially disposed around each disk directs amplified light emission, either toward a common point or in a common direction. (Official Gazette)

  3. Torque expression in self-ligating orthodontic brackets and conventionally ligated brackets: A systematic review

    PubMed Central

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

    2017-01-01

    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

  4. Dye laser amplifier

    DOEpatents

    Moses, Edward I.

    1992-01-01

    An improved dye laser amplifier is disclosed. The efficiency of the dye lr amplifier is increased significantly by increasing the power of a dye beam as it passes from an input window to an output window within the dye chamber, while maintaining the intensity of the dye beam constant.

  5. Dye laser amplifier

    DOEpatents

    Moses, E.I.

    1992-12-01

    An improved dye laser amplifier is disclosed. The efficiency of the dye laser amplifier is increased significantly by increasing the power of a dye beam as it passes from an input window to an output window within the dye chamber, while maintaining the intensity of the dye beam constant. 3 figs.

  6. DIRECT COUPLED AMPLIFIER

    DOEpatents

    Dandl, R.A.

    1961-09-19

    A transistor amplifier is designed for vyery small currents below 10/sup -8/ amperes. The filrst and second amplifier stages use unusual selected transistors in which the current amplification increases markedly for values of base current below 10/sup -6/ amperes.

  7. DISTRIBUTED AMPLIFIER INCORPORATING FEEDBACK

    DOEpatents

    Bell, P.R. Jr.

    1958-10-21

    An improved distributed amplifier system employing feedback for stabilization is presented. In accordance with the disclosed invention, a signal to be amplified is applled to one end of a suitable terminated grid transmission line. At intervals along the transmission line, the signal is fed to stable, resistance-capacitance coupled amplifiers incorporating feedback loops therein. The output current from each amplifier is passed through an additional tube to minimize the electrostatic capacitance between the tube elements of the last stage of the amplifier, and fed to appropriate points on an output transmission line, similar to the grid line, but terminated at the opposite (input) end. The output taken from the unterminated end of the plate transmission line is proportional to the input voltage impressed upon the grid line.

  8. Versatile composite amplifier configuration

    NASA Astrophysics Data System (ADS)

    Gift, Stephan J. G.; Maundy, Brent

    2015-06-01

    This paper describes a versatile composite amplifier in which a current feedback amplifier (CFA) drives an operational amplifier (OPA). In the conventional OPA-CFA composite amplifier, an OPA drives a CFA resulting in a composite structure that combines the DC input stability of the OPA and the high speed capability of the CFA. The proposed composite configuration combines different features of the CFA and OPA, specifically the constant bandwidth property of the CFA and the high power and high current output capacity of the OPA. The new circuit is easily implemented in the standard inverting and non-inverting configurations using commercially available devices, and the accuracy and constant bandwidth features were experimentally verified. Local feedback around the associated CFA ensures that the proposed composite amplifier possesses a higher level of bandwidth constancy than a single CFA.

  9. Oligonucleotide Ligation Assay for Detecting Mutations in the Human Immunodeficiency Virus Type 1 pol Gene That Are Associated with Resistance to Zidovudine, Didanosine, and Lamivudine

    PubMed Central

    Edelstein, Reva E.; Nickerson, Deborah A.; Tobe, Vincent O.; Manns-Arcuino, Laura A.; Frenkel, Lisa M.

    1998-01-01

    This report describes the detection of mutations in the pol gene of human immunodeficiency virus type 1 associated with resistance to zidovudine, didanosine, and lamivudine by genotyping by an oligonucleotide ligation assay specific codons in the pol gene amplified by PCR. Our studies demonstrate the sensitivity, simplicity, and specificity of this genotyping system. PMID:9466779

  10. Post tubal ligation syndrome or iatrogenic hydrosalpinx.

    PubMed

    Gregory, M G

    1981-10-01

    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

  11. Auto-Zero Differential Amplifier

    NASA Technical Reports Server (NTRS)

    Quilligan, Gerard T. (Inventor); Aslam, Shahid (Inventor)

    2017-01-01

    An autozero amplifier may include a window comparator network to monitor an output offset of a differential amplifier. The autozero amplifier may also include an integrator to receive a signal from a latched window comparator network, and send an adjustment signal back to the differential amplifier to reduce an offset of the differential amplifier.

  12. Universal signal conditioning amplifier

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro J.; Hallberg, Carl; Cecil, Jim

    1994-01-01

    A state-of-the-art instrumentation amplifier capable of being used with most types of transducers has been developed at the Kennedy Space Center. This Universal Signal Conditioning Amplifier (USCA) can eliminate costly measurement setup item and troubleshooting, improve system reliability and provide more accurate data than conventional amplifiers. The USCA can configure itself for maximum resolution and accuracy based on information read from a RAM chip attached to each transducer. Excitation voltages or current are also automatically configured. The amplifier uses both analog and digital state-of-the-art technology with analog-to-digital conversion performed in the early stages in order to minimize errors introduced by offset and gain drifts in the analog components. A dynamic temperature compensation scheme has been designed to achieve and maintain 12-bit accuracy of the amplifier from 0 to 70 C. The digital signal processing section allows the implementation of digital filters up to 511th order. The amplifier can also perform real-time linearizations up to fourth order while processing data at a rate of 23.438 kS/s. Both digital and analog outputs are available from the amplifier.

  13. Tuning Broadband Microwave Amplifiers

    SciTech Connect

    Alaniz, Gabriel

    2003-09-05

    The PEP-II/DA {Phi} NE/ALS longitudinal feedback systems are complex wide bandwidth systems requiring analog, digital and microwave circuits. The solid-state amplifier is one of the components in the microwave circuit that is required to suppress the coupled bunch instabilities that exist in the PEP-II accelerator. The suppression is achieved by using an antenna as a kicker structure that provides an electric field in order to increase or decrease the energy of particles passing through the structure. The amplifier is made up of sixteen 30 to 35W microstrip GaAs FET modules that are combined to obtain 500W over a bandwidth of 850MHz to 1850MHz. The amplifier malfunctioned causing a reduction in the functionality and power output of the individual GaAs FET modules. The amplifier must be repaired. After repair, the amplifier must be tuned to optimize the gain while maintaining proper power output. The amplifier is tuned using microstrip circuit techniques. A variety of microstrip methods are used to obtain the proper line impedance. The result is a working amplifier that operates efficiently.

  14. Ligation-mediated PCR with a back-to-back adapter reduces amplification bias resulting from variations in GC content.

    PubMed

    Ishihara, Satoru; Kotomura, Naoe; Yamamoto, Naoki; Ochiai, Hiroshi

    2017-08-15

    Ligation-mediated polymerase chain reaction (LM-PCR) is a common technique for amplification of a pool of DNA fragments. Here, a double-stranded oligonucleotide consisting of two primer sequences in back-to-back orientation was designed as an adapter for LM-PCR. When DNA fragments were ligated with this adapter, the fragments were sandwiched between two adapters in random orientations. In the ensuing PCR, ligation products linked at each end to an opposite side of the adapter, i.e. to a distinct primer sequence, were preferentially amplified compared with products linked at each end to an identical primer sequence. The use of this adapter in LM-PCR reduced the impairment of PCR by substrate DNA with a high GC content, compared with the use of traditional LM-PCR adapters. This result suggested that our method has the potential to contribute to reduction of the amplification bias that is caused by an intrinsic property of the sequence context in substrate DNA. A DNA preparation obtained from a chromatin immunoprecipitation assay using pulldown of a specific form of histone H3 was successfully amplified using the modified LM-PCR, and the amplified products could be used as probes in a fluorescence in situ hybridization analysis. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. An optically isolated amplifier

    NASA Astrophysics Data System (ADS)

    Smith, C. J.

    1982-11-01

    The design presented was used for biomedical signal detection and monitoring. The amplifier was successfully applied for EMG and ECG research studies. The patient is safely isolated from the processing equipment when using the amplifier. This opto-isolated amplifier was also applied industrially for monitoring mercury arc rectifier control signals. The device has proved itself in an industrial environment as an interface for a microprocessor. This unit can be used whenever large offset voltages are found, and can therefore be put to good use in many power electrical engineering applications.

  16. Amplify Interest in STS.

    ERIC Educational Resources Information Center

    Chiappetta, Eugene L; Mays, John D.

    1992-01-01

    Presents activities in which students construct simple crystal radio sets and amplifiers out of diodes, transistors, and integrated circuits. Provides conceptual background, materials needed, instructions, diagrams, and classroom applications. (MDH)

  17. Amplify Interest in STS.

    ERIC Educational Resources Information Center

    Chiappetta, Eugene L; Mays, John D.

    1992-01-01

    Presents activities in which students construct simple crystal radio sets and amplifiers out of diodes, transistors, and integrated circuits. Provides conceptual background, materials needed, instructions, diagrams, and classroom applications. (MDH)

  18. Fully relayed regenerative amplifier

    DOEpatents

    Glass, Alexander J.

    1981-01-01

    A regenerative laser apparatus and method using the optical relay concept to maintain high fill factors, to suppress diffraction effects, and to minimize phase distortions in a regenerative amplifier.

  19. Neurodevelopmental Outcomes Following Two Different Treatment Approaches (Early Ligation versus Selective Ligation) for Patent Ductus Arteriosus

    PubMed Central

    Wickremasinghe, Andrea C.; Rogers, Elizabeth E.; Piecuch, Robert E.; Johnson, Bridget C.; Golden, Suzanne; Moon-Grady, Anita J.; Clyman, Ronald I.

    2012-01-01

    Objective To examine whether a change in the approach to management of persistent patent ductus arteriosus (PDA), from “early ligation” to “selective ligation,” is associated with an increased risk of abnormal neurodevelopmental outcome. Study design In 2005, we changed our PDA treatment protocol (in infants ≤27 6/7 weeks gestation) from an “early ligation” approach, with PDA ligation quickly if they failed to close after indomethacin (Period 1: 1/99–12/04), to a “selective ligation” approach, with PDA ligation only if specific criteria were met (Period 2: 1/05–5/09). All infants in both periods received prophylactic indomethacin. Multivariate analysis was used to compare the odds of a composite Abnormal Neurodevelopmental Outcome (Bayley MDI or Cognitive score <70, cerebral palsy, blindness, and/or deafness) associated with each treatment approach at 18–36 months (n=224). Results During Period 1, 23% of the infants in follow-up failed indomethacin treatment, and all were ligated; during Period 2, 30% of infants failed indomethacin, and 66% were ligated after meeting pre-specified criteria. Infants treated with the “selective ligation” strategy had fewer Abnormal Outcomes than infants treated with the “early ligation” approach (OR=0.07, p=0.046). Infants ligated before 10 days of age had an increased incidence of Abnormal Neurodevelopmental Outcome. The significant difference in outcomes between the two PDA treatment strategies could be accounted for, in part, by the earlier age of ligation during Period 1. Conclusions A “selective ligation” approach for PDAs that fail to close with indomethacin does not worsen neurodevelopmental outcome at 18–36 months. PMID:22795222

  20. High stability amplifier

    NASA Technical Reports Server (NTRS)

    Adams, W. A.; Reinhardt, V. S. (Inventor)

    1983-01-01

    An electrical RF signal amplifier for providing high temperature stability and RF isolation and comprised of an integrated circuit voltage regulator, a single transistor, and an integrated circuit operational amplifier mounted on a circuit board such that passive circuit elements are located on side of the circuit board while the active circuit elements are located on the other side is described. The active circuit elements are embedded in a common heat sink so that a common temperature reference is provided for changes in ambient temperature. The single transistor and operational amplifier are connected together to form a feedback amplifier powered from the voltage regulator with transistor implementing primarily the desired signal gain while the operational amplifier implements signal isolation. Further RF isolation is provided by the voltage regulator which inhibits cross-talk from other like amplifiers powered from a common power supply. Input and output terminals consisting of coaxial connectors are located on the sides of a housing in which all the circuit components and heat sink are located.

  1. A specific instrument to facilitate thoracoscopic ligation.

    PubMed

    Wei, Bo; Jiang, Fusheng; Yin, Jinshu

    2014-09-01

    The rigid wall of the thoracic cavity provides an ideal cavity for minimally invasive surgery without the need for the cumbersome CO2 insufflation that is essential to perform laparoscopic surgery. And by that, the novel ligation technique facilitating minithoracotomy, which we published before, is possible to be transferred to the video-assisted thoracoscopic surgery (VATS). We attempt to modify the structure of the conventional right angle forceps and its usage so as to accommodate VATS. The unique shape of this instrument facilitates its passage through a trocar or a true VATS intercostal access instead of a rib spreading minithoracotomy. Its clinical performance renders that it a cheaper and better alternative to commercially available products. This new device has the potential to make a substantial contribution to the manual ligation practice of VATS. Georg Thieme Verlag KG Stuttgart · New York.

  2. Left atrial laceration with epicardial ligation device.

    PubMed

    Keating, Vincent P; Kolibash, Christopher P; Khandheria, Bijoy K; Bajwa, Tanvir; Sra, Jasbir; Kress, David C

    2014-01-01

    Many new devices and techniques are being developed to attempt a reduction in embolic stroke risk for patients with atrial fibrillation who are either unable or unwilling to maintain long-term anticoagulation. One of these new devices (LARIAT®, SentreHEART Inc., Redwood City, California, USA) employs delivery of an epicardial suture to ligate the left atrial appendage after percutaneous pericardial and transseptal access. This series presents three clinical cases that demonstrate a serious and recurrent complication of left atrial laceration and cardiac tamponade shortly following delivery of an epicardial suture ligation to the left atrial appendage. Three clinical cases are described in detail with pre- and postprocedure angiography and echocardiography as well as illustrations reflecting the surgeon's findings on direct visualization of the left atrial lacerations postligation. Potential hypotheses of each injury are examined in light of the case timelines and findings at sternotomy. There was no suggestion that tamponade was related to pericardial or transseptal access, but rather a complication with device delivery. These three patients quickly progressed to clinical cardiac tamponade despite attempted drainage, stressing the importance of cardiovascular surgery backup, including a cardiopulmonary bypass pump, when delivering novel, percutaneous ligation devices for the left atrial appendage.

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

    SciTech Connect

    Delahunty, C.; Ankener, W.; Deng, Qiang

    1996-06-01

    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.

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

    PubMed Central

    Delahunty, C.; Ankener, W.; Deng, Q.; Eng, J.; Nickerson, D. A.

    1996-01-01

    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 colorimetric 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. Images Figure 2 PMID:8651301

  5. Usefulness of ligation-mediated PCR genotyping in tracking outbreak-associated Mycobacterium tuberculosis strains.

    PubMed

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

    2005-01-01

    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.

  6. Multiplexed analysis of fixed tissue RNA using Ligation in situ Hybridization.

    PubMed

    Credle, Joel J; Itoh, Christopher Y; Yuan, Tiezheng; Sharma, Rajni; Scott, Erick R; Workman, Rachael E; Fan, Yunfan; Housseau, Franck; Llosa, Nicolas J; Bell, W Robert; Miller, Heather; Zhang, Sean X; Timp, Winston; Larman, H Benjamin

    2017-08-21

    Clinical tissues are prepared for histological analysis and long-term storage via formalin fixation and paraffin embedding (FFPE). The FFPE process results in fragmentation and chemical modification of RNA, rendering it less suitable for analysis by techniques that rely on reverse transcription (RT) such as RT-qPCR and RNA-Seq. Here we describe a broadly applicable technique called 'Ligation in situ Hybridization' ('LISH'), which is an alternative methodology for the analysis of FFPE RNA. LISH utilizes the T4 RNA Ligase 2 to efficiently join adjacent chimeric RNA-DNA probe pairs hybridized in situ on fixed RNA target sequences. Subsequent treatment with RNase H releases RNA-templated ligation products into solution for downstream analysis. We demonstrate several unique advantages of LISH-based assays using patient-derived FFPE tissue. These include >100-plex capability, compatibility with common histochemical stains and suitability for analysis of decade-old materials and exceedingly small microdissected tissue fragments. High-throughput DNA sequencing modalities, including single molecule sequencing, can be used to analyze ligation products from complex panels of LISH probes ('LISH-seq'), which can be amplified efficiently and with negligible bias. LISH analysis of FFPE RNA is a novel methodology with broad applications that range from multiplexed gene expression analysis to the sensitive detection of infectious organisms. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  7. Oligonucleotide gap-fill ligation for mutation detection and sequencing in situ.

    PubMed

    Mignardi, Marco; Mezger, Anja; Qian, Xiaoyan; La Fleur, Linnea; Botling, Johan; Larsson, Chatarina; Nilsson, Mats

    2015-12-15

    In clinical diagnostics a great need exists for targeted in situ multiplex nucleic acid analysis as the mutational status can offer guidance for effective treatment. One well-established method uses padlock probes for mutation detection and multiplex expression analysis directly in cells and tissues. Here, we use oligonucleotide gap-fill ligation to further increase specificity and to capture molecular substrates for in situ sequencing. Short oligonucleotides are joined at both ends of a padlock gap probe by two ligation events and are then locally amplified by target-primed rolling circle amplification (RCA) preserving spatial information. We demonstrate the specific detection of the A3243G mutation of mitochondrial DNA and we successfully characterize a single nucleotide variant in the ACTB mRNA in cells by in situ sequencing of RCA products generated by padlock gap-fill ligation. To demonstrate the clinical applicability of our assay, we show specific detection of a point mutation in the EGFR gene in fresh frozen and formalin-fixed, paraffin-embedded (FFPE) lung cancer samples and confirm the detected mutation by in situ sequencing. This approach presents several advantages over conventional padlock probes allowing simpler assay design for multiplexed mutation detection to screen for the presence of mutations in clinically relevant mutational hotspots directly in situ.

  8. Surface ligation-based resonance light scattering analysis of methylated genomic DNA on a microarray platform.

    PubMed

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

    2016-05-10

    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.

  9. Ligating Internal Iliac Artery: Success beyond Hesitation.

    PubMed

    Singh, Abha; Kishore, Ruchi; Saxena, Saveri Sarbhai

    2016-10-01

    To study the outcomes, benefits and complications of internal iliac artery ligation in both obstetric and gynecological cases. To study the outcomes, effectiveness and complications of internal iliac artery ligation (IIAL). This is an analytical longitudinal study done among women who have undergone internal iliac artery ligation in Dr. BRAMH a tertiary referral center from July 2013 to June 2015. Follow-up was done through color Doppler analysis of pelvic arteries before discharge, after 6 weeks and after 6 months. The efficacy of IIAL was 96.87 %. The mean shock index was 0.94 ± 0.26. Sixty-four women underwent IIAL out of which placenta previa (21.8 %) was the major indication. There were four maternal deaths. There were no intraoperative or ischemic complications. The greater the time interval between onset of hemorrhage and IIAL, the graver the outcome. For all women in whom uterus could be salvaged, resumption of menstrual cycles was seen within 6 months of IIAL. There was a significant decrease in the RI and PI of uterine arteries. In the ovarian arteries, there was a significant increase in RI and no significant change in PI initially. Flow in distal part of ligated internal iliac arteries could be detected in 54 (90 %) women out of 60 after 6 months of ligation of internal iliac arteries. IIAL is an effective life-saving method to control obstetric and gynecological hemorrhage, and a hysterectomy can often be avoided. Early resort to IIAL is vital for improving the patient outcome. Uterine perfusion is well maintained, while there may be a decrease in ovarian perfusion. Resumption of menstrual cycles and presence of distal flow in internal iliac artery within 6 months suggest the preservation of future fertility; in order to better understand the impact of IIAL on ovarian functions and future fertility, larger studies with longer follow-up periods need to be conducted.

  10. Laser amplifier and method

    DOEpatents

    Backus, S.; Kapteyn, H.C.; Murnane, M.M.

    1997-07-01

    Laser amplifiers and methods for amplifying a laser beam are disclosed. A representative embodiment of the amplifier comprises first and second curved mirrors, a gain medium, a third mirror, and a mask. The gain medium is situated between the first and second curved mirrors at the focal point of each curved mirror. The first curved mirror directs and focuses a laser beam to pass through the gain medium to the second curved mirror which reflects and recollimates the laser beam. The gain medium amplifies and shapes the laser beam as the laser beam passes therethrough. The third mirror reflects the laser beam, reflected from the second curved mirror, so that the laser beam bypasses the gain medium and return to the first curved mirror, thereby completing a cycle of a ring traversed by the laser beam. The mask defines at least one beam-clipping aperture through which the laser beam passes during a cycle. The gain medium is pumped, preferably using a suitable pumping laser. The laser amplifier can be used to increase the energy of continuous-wave or, especially, pulsed laser beams including pulses of femtosecond duration and relatively high pulse rate. 7 figs.

  11. Laser amplifier and method

    DOEpatents

    Backus, Sterling; Kapteyn, Henry C.; Murnane, Margaret M.

    1997-01-01

    Laser amplifiers and methods for amplifying a laser beam are disclosed. A representative embodiment of the amplifier comprises first and second curved mirrors, a gain medium, a third mirror, and a mask. The gain medium is situated between the first and second curved mirrors at the focal point of each curved mirror. The first curved mirror directs and focuses a laser beam to pass through the gain medium to the second curved mirror which reflects and recollimates the laser beam. The gain medium amplifies and shapes the laser beam as the laser beam passes therethough. The third mirror reflects the laser beam, reflected from the second curved mirror, so that the laser beam bypasses the gain medium and return to the first curved mirror, thereby completing a cycle of a ring traversed by the laser beam. The mask defines at least one beam-clipping aperture through which the laser beam passes during a cycle. The gain medium is pumped, preferably using a suitable pumping laser. The laser amplifier can be used to increase the energy of continuous-wave or, especially, pulsed laser beams including pulses of femtosecond duration and relatively high pulse rate.

  12. Electrospun Amplified Fiber Optics

    PubMed Central

    2015-01-01

    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. PMID:25710188

  13. High input impedance amplifier

    NASA Technical Reports Server (NTRS)

    Kleinberg, Leonard L.

    1995-01-01

    High input impedance amplifiers are provided which reduce the input impedance solely to a capacitive reactance, or, in a somewhat more complex design, provide an extremely high essentially infinite, capacitive reactance. In one embodiment, where the input impedance is reduced in essence, to solely a capacitive reactance, an operational amplifier in a follower configuration is driven at its non-inverting input and a resistor with a predetermined magnitude is connected between the inverting and non-inverting inputs. A second embodiment eliminates the capacitance from the input by adding a second stage to the first embodiment. The second stage is a second operational amplifier in a non-inverting gain-stage configuration where the output of the first follower stage drives the non-inverting input of the second stage and the output of the second stage is fed back to the non-inverting input of the first stage through a capacitor of a predetermined magnitude. These amplifiers, while generally useful, are very useful as sensor buffer amplifiers that may eliminate significant sources of error.

  14. Amplified DNA Biosensors

    NASA Astrophysics Data System (ADS)

    Willner, Itamar; Shlyahovsky, Bella; Willner, Bilha; Zayats, Maya

    Amplified detection of DNA is a central research topic in modern bioanalytical science. Electronic or optical transduction of DNA recognition events provides readout signals for DNA biosensors. Amplification of the DNA analysis is accomplished by the coupling of nucleic acid-functionalized enzymes or nucleic acid-functionalized nanoparticles (NP) as labels for the DNA duplex formation. This chapter discusses the amplified amperometric analysis of DNA by redox enzymes, the amplified optical sensing of DNA by enzymes or DNAzymes, and the amplified voltammetric, optical, or microgravimetric analysis of DNA using metallic or semiconductor nanoparticles. Further approaches to amplify DNA detection involve the use of micro-carriers of redox compounds as labels for DNA complex formation on electrodes, or the use of micro-objects such as liposomes, that label the resulting DNA complexes on electrodes and alter the interfacial properties of the electrodes. Finally, DNA machines are used for the optical detection of DNA, and the systems are suggested as future analytical procedures that could substitute the polymerase chain reaction (PCR) process.

  15. Electrospun amplified fiber optics.

    PubMed

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

    2015-03-11

    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.

  16. STABILIZED FEEDBACK AMPLIFIER

    DOEpatents

    Fishbine, H.L.; Sewell, C. Jr.

    1957-08-01

    Negative feedback amplifiers, and particularly a negative feedback circuit which is economical on amode power consumption, are described. Basically, the disclosed circuit comprises two tetrode tubes where the output of the first tube is capacitamce coupled to the grid of the second tube, which in turn has its plate coupled to the cathode of the first tube to form a degenerative feedback circuit. Operating potential for screen of the second tube is supplied by connecting the cathode resistor of the first tube to the screen, while the screen is by-passed to the cathode of its tube for the amplified frequencies. Also, the amplifier incorporates a circuit to stabilize the transconductance of the tubes by making the grid potential of each tube interdependent on anode currents of both lubes by voltage divider circuitry.

  17. A grid amplifier

    NASA Technical Reports Server (NTRS)

    Kim, Moonil; Weikle, Robert M., II; Hacker, Jonathan B.; Delisio, Michael P.; Rutledge, David B.; Rosenberg, James J.; Smith, R. P.

    1991-01-01

    A 50-MESFET grid amplifier is reported that has a gain of 11 dB at 3.3 GHz. The grid isolates the input from the output by using vertical polarization for the input beam and horizontal polarization for the transmitted output beam. The grid unit cell is a two-MESFET differential amplifier. A simple calibration procedure allows the gain to be calculated from a relative power measurement. This grid is a hybrid circuit, but the structure is suitable for fabrication as a monolithic wafer-scale integrated circuit, particularly at millimeter wavelengths.

  18. Spatial Light Amplifier Modulators

    NASA Technical Reports Server (NTRS)

    Eng, Sverre T.; Olsson, N. Anders

    1992-01-01

    Spatial light amplifier modulators (SLAM's) are conceptual devices that effect two-dimensional spatial modulation in optical computing and communication systems. Unlike current spatial light modulators, these provide gain. Optical processors incorporating SLAM's designed to operate in reflection or transmission mode. Each element of planar SLAM array is optical amplifier - surface-emitting diode laser. Array addressed electrically with ac modulating signals superimposed on dc bias currents supplied to lasers. SLAM device provides both desired modulation and enough optical gain to enable splitting of output signal into many optical fibers without excessive loss of power.

  19. A grid amplifier

    NASA Technical Reports Server (NTRS)

    Kim, Moonil; Weikle, Robert M., II; Hacker, Jonathan B.; Delisio, Michael P.; Rutledge, David B.; Rosenberg, James J.; Smith, R. P.

    1991-01-01

    A 50-MESFET grid amplifier is reported that has a gain of 11 dB at 3.3 GHz. The grid isolates the input from the output by using vertical polarization for the input beam and horizontal polarization for the transmitted output beam. The grid unit cell is a two-MESFET differential amplifier. A simple calibration procedure allows the gain to be calculated from a relative power measurement. This grid is a hybrid circuit, but the structure is suitable for fabrication as a monolithic wafer-scale integrated circuit, particularly at millimeter wavelengths.

  20. Universal signal conditioning amplifier

    NASA Technical Reports Server (NTRS)

    Larson, William E.; Hallberg, Carl; Medelius, Pedro J.

    1994-01-01

    Engineers at NASA's Kennedy Space Center have designed a signal conditioning amplifier which automatically matches itself to almost any kind of transducer. The product, called Universal Signal Conditioning Amplifier (USCA), uses state-of-the-art technologies to deliver high accuracy measurements. USCA's features which can be either programmable or automated include: voltage, current, or pulsed excitation, unlimited resolution gain, digital filtering and both analog and digital output. USCA will be used at Kennedy Space Center's launch pads for environmental measurements such as vibrations, strains, temperatures and overpressures. USCA is presently being commercialized through a co-funded agreement between NASA, the State of Florida, and Loral Test and Information Systems, Inc.

  1. Fourier plane image amplifier

    DOEpatents

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

    1995-12-12

    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.

  2. New microelectronic power amplifier

    NASA Technical Reports Server (NTRS)

    New, T. C.

    1968-01-01

    Integrated push-pull power amplifier fabricated on a chip of silicon has interdigitated power transistors and is hermetically encapsulated in a beryllia flat package. It provides current output greater than the nominal 10 amperes from an input current drive of 1 ampere.

  3. The radical amplifier

    NASA Technical Reports Server (NTRS)

    Hastie, D. R.

    1994-01-01

    The radical amplifier as a method for measuring radical concentrations in the atmosphere has received renewed attention lately. In principle, it can measure the total concentration of HO(x) and RO(x) radicals by reacting ambient air with high concentrations of CO (3-10 percent) and NO (2-6 ppmv), and measuring the NO2 produced.

  4. Improved RF Isolation Amplifier

    NASA Technical Reports Server (NTRS)

    Stevens, G. L.; Macconnell, J.

    1985-01-01

    Circuit has high reverse isolation and wide bandwidth. Wideband isolation amplifier has low intermodulation distortion and high reverse isolation. Circuit does not require selected or matched components or directional coupling device. Circuit used in applications requiring high reverse isolation such as receiver intermediate-frequency (IF) strips and frequency distribution systems. Also applicable in RF and video signaling.

  5. Fourier plane image amplifier

    DOEpatents

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

    1995-01-01

    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.

  6. Enzyme-mediated ligation technologies for peptides and proteins.

    PubMed

    Schmidt, Marcel; Toplak, Ana; Quaedflieg, Peter Jlm; Nuijens, Timo

    2017-02-18

    With the steadily increasing complexity and quantity requirements for peptides in industry and academia, the efficient and site-selective ligation of peptides and proteins represents a highly desirable goal. Within this context, enzyme-mediated ligation technologies for peptides and proteins have attracted great interest in recent years as they represent an extremely powerful extension to the scope of chemical methodologies (e.g. native chemical ligation) in basic and applied research. Compared to chemical ligation methods, enzymatic strategies using ligases such as sortase, butelase, peptiligase or omniligase generally feature excellent chemoselectivity, therefore making them valuable tools for protein and peptide chemists.

  7. Detachable endoloop vs. elastic band ligation for bleeding esophageal varices.

    PubMed

    Naga, Mazen Ibrahim; Okasha, Hussein Hassan; Foda, Ayman Ragaei; Gomaa, Mohamed Saeed; Fouad, Ayman Mohamed; Masoud, Amgad Gerges; El-din, Hazem Hossam

    2004-06-01

    Variceal bleeding is a serious complication with a mortality rate that ranges from 20% to 50%. Patients who have variceal hemorrhage usually are treated by endoscopic injection sclerotherapy or elastic band ligation to eradicate the varices. Endoloop ligation is a newly developed technique for achieving hemostasis and variceal eradication. This study compared endoloop ligation with elastic band ligation in patients with acute esophageal variceal bleeding. Fifty patients with acute esophageal variceal bleeding were recruited: 25 were treated by elastic band ligation and 25 by endoloop ligation. Although the number of patients in whom bleeding recurred during a follow-up period of 6 months was smaller in the endoloop group (12%) vs. the band group (28%), this difference was not statistically significant. Furthermore, no statistically significant difference was found between the two groups with respect to the number of patients in whom variceal eradication was achieved, the number of treatment sessions required for variceal eradication, or the frequency of variceal recurrence. The total cost for variceal obliteration by endoloop ligation was 342 dollars per patient, whereas, the total cost of variceal eradication by elastic band ligation was 356 dollars per patient. The endoloop had certain technical advantages over band application: a better field of vision, tighter application, good results with junctional varices, and a lack of strain exerted by the device on the endoscope. Endoloop ligation is a promising new technique for management of patients with bleeding esophageal varices.

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

    PubMed

    Tiernan, Jim; Hind, Daniel; Watson, Angus; Wailoo, Allan J; Bradburn, Michael; Shephard, Neil; Biggs, Katie; Brown, Steven

    2012-10-25

    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. 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. A multi-centre, parallel group randomised controlled trial. The primary outcome is patient-reported symptom recurrence twelve months following the intervention. Secondary outcome measures relate to symptoms, complications, health resource use, health related quality of life and cost

  9. Efficient in situ detection of mRNAs using the Chlorella virus DNA ligase for padlock probe ligation.

    PubMed

    Schneider, Nils; Meier, Matthias

    2017-02-01

    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. © 2017 Schneider and Meier; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  10. Streamlined expressed protein ligation using split inteins.

    PubMed

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

    2013-01-09

    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.

  11. Respiratory variables during thoracotomy for PDA ligation.

    PubMed

    Puri, G D; Hariwir, S; Chari, P; Gujral, J S

    1996-06-01

    Physiological deadspace fraction of tidal volume (VD/VT), arterial to end-tidal carbon dioxide tension differences [P(a-E')CO2], arterial oxygen tension (PaO2) and respiratory system compliance were studied in twenty patients with patent ductus ateriosus scheduled for multiple ligation and transfixation through posterolateral thoracotomy under general anaesthesia with controlled ventilation. The study period was divided into six stages: stage 1--supine posture under anaesthesia, stage 2--lateral posture before start of surgery, stage 3--after chest opening before lung manipulation, stage 4--after ductus ligation and lung re-expansion before chest closure, stage 5--lateral posture, chest closed, stage 6--supine stage before reversal. There was a significant (P < 0.01) increase of VD/VT on attaining the lateral posture. The fraction decreased significantly (P < 0.05) on opening of the chest (stage 3) and subsequently increased at stage 4. There was no significant change in mean P(a-E')CO2 at various stages of thoracotomy. PaO2 fell significantly on opening of the chest and was lowest before chest closure (stage 4). PaO2 increased following chest closure but was still significantly lower than the pre-surgical supine stage. Respiratory system compliance was lowest at stage 4. Changes in deadspace fraction VD/VT do not correspond favourably to arterial oxygen tensions during posterolateral thoractomy.

  12. As fast and selective as enzymatic ligations: unpaired nucleobases increase the selectivity of DNA-controlled native chemical PNA ligation.

    PubMed

    Ficht, Simon; Dose, Christian; Seitz, Oliver

    2005-11-01

    DNA-controlled reactions offer interesting opportunities in biological, chemical, and nanosciences. In practical applications, such as in DNA sequence analysis, the sequence fidelity of the chemical-ligation reaction is of central importance. We present a ligation reaction that is as fast as and much more selective than enzymatic T4 ligase-mediated oligonucleotide ligations. The selectivity was higher than 3000-fold in discriminating matched from singly mismatched DNA templates. It is demonstrated that this enormous selectivity is the hallmark of the particular ligation architecture, which is distinct from previous ligation architectures designed as "nick ligations". Interestingly, the fidelity of the native chemical ligation of peptide nucleic acids was increased by more than one order of magnitude when performing the ligation in such a way that an abasic-site mimic was formed opposite an unpaired template base. It is shown that the high sequence fidelity of the abasic ligation could facilitate the MALDI-TOF mass-spectrometric analysis of early cancer onset by allowing the detection of as little as 0.2 % of single-base mutant DNA in the presence of 99.8 % wild-type DNA.

  13. PEAK LIMITING AMPLIFIER

    DOEpatents

    Goldsworthy, W.W.; Robinson, J.B.

    1959-03-31

    A peak voltage amplitude limiting system adapted for use with a cascade type amplifier is described. In its detailed aspects, the invention includes an amplifier having at least a first triode tube and a second triode tube, the cathode of the second tube being connected to the anode of the first tube. A peak limiter triode tube has its control grid coupled to thc anode of the second tube and its anode connected to the cathode of the second tube. The operation of the limiter is controlled by a bias voltage source connected to the control grid of the limiter tube and the output of the system is taken from the anode of the second tube.

  14. Optimization of plasma amplifiers

    DOE PAGES

    Sadler, James D.; Trines, Raoul M. G. M.; Tabak, Max; ...

    2017-05-24

    Here, plasma amplifiers offer a route to side-step limitations on chirped pulse amplification and generate laser pulses at the power frontier. They compress long pulses by transferring energy to a shorter pulse via the Raman or Brillouin instabilities. We present an extensive kinetic numerical study of the three-dimensional parameter space for the Raman case. Further particle-in-cell simulations find the optimal seed pulse parameters for experimentally relevant constraints. The high-efficiency self-similar behavior is observed only for seeds shorter than the linear Raman growth time. A test case similar to an upcoming experiment at the Laboratory for Laser Energetics is found tomore » maintain good transverse coherence and high-energy efficiency. Effective compression of a 10kJ, nanosecond-long driver pulse is also demonstrated in a 15-cm-long amplifier.« less

  15. STABILIZED TRANSISTOR AMPLIFIER

    DOEpatents

    Noe, J.B.

    1963-05-01

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

  16. Monolithic dye laser amplifier

    DOEpatents

    Kuklo, Thomas C.

    1993-01-01

    A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

  17. Monolithic dye laser amplifier

    DOEpatents

    Kuklo, T.C.

    1993-03-30

    A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

  18. Amplifying genetic logic gates.

    PubMed

    Bonnet, Jerome; Yin, Peter; Ortiz, Monica E; Subsoontorn, Pakpoom; Endy, Drew

    2013-05-03

    Organisms must process information encoded via developmental and environmental signals to survive and reproduce. Researchers have also engineered synthetic genetic logic to realize simpler, independent control of biological processes. We developed a three-terminal device architecture, termed the transcriptor, that uses bacteriophage serine integrases to control the flow of RNA polymerase along DNA. Integrase-mediated inversion or deletion of DNA encoding transcription terminators or a promoter modulates transcription rates. We realized permanent amplifying AND, NAND, OR, XOR, NOR, and XNOR gates actuated across common control signal ranges and sequential logic supporting autonomous cell-cell communication of DNA encoding distinct logic-gate states. The single-layer digital logic architecture developed here enables engineering of amplifying logic gates to control transcription rates within and across diverse organisms.

  19. Optimization of plasma amplifiers

    NASA Astrophysics Data System (ADS)

    Sadler, James D.; Trines, Raoul M. Â. G. Â. M.; Tabak, Max; Haberberger, Dan; Froula, Dustin H.; Davies, Andrew S.; Bucht, Sara; Silva, Luís O.; Alves, E. Paulo; Fiúza, Frederico; Ceurvorst, Luke; Ratan, Naren; Kasim, Muhammad F.; Bingham, Robert; Norreys, Peter A.

    2017-05-01

    Plasma amplifiers offer a route to side-step limitations on chirped pulse amplification and generate laser pulses at the power frontier. They compress long pulses by transferring energy to a shorter pulse via the Raman or Brillouin instabilities. We present an extensive kinetic numerical study of the three-dimensional parameter space for the Raman case. Further particle-in-cell simulations find the optimal seed pulse parameters for experimentally relevant constraints. The high-efficiency self-similar behavior is observed only for seeds shorter than the linear Raman growth time. A test case similar to an upcoming experiment at the Laboratory for Laser Energetics is found to maintain good transverse coherence and high-energy efficiency. Effective compression of a 10 kJ , nanosecond-long driver pulse is also demonstrated in a 15-cm-long amplifier.

  20. Man-Amplifying Exoskeleton

    NASA Astrophysics Data System (ADS)

    Rosheim, Mark E.

    1990-03-01

    This paper describes a design for a man-amplifying exoskeleton, an electrically powered, articulated frame worn by an operator. The design features modular construction and employ anthropomorphic pitch-yaw joints for arms and legs. These singularity-free designs offer a significant advancement over simple pivot-type joints used in older designs. Twenty-six degrees-of-freedom excluding the hands gives the Man-Amplifier its unique dexterity. A five hundred-pound load capacity is engineered for a diverse range of tasks. Potential applications in emergency rescue work, restoring functionality to the handicapped, and military applications ranging from material handling to an elite fighting core are discussed. A bibliography concludes this paper.

  1. Helical Fiber Amplifier

    DOEpatents

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

    2002-12-17

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

  2. Longitudinal space charge amplifier

    NASA Astrophysics Data System (ADS)

    Schneidmiller, E. A.; Yurkov, M. V.

    2013-05-01

    Longitudinal space charge (LSC) driven microbunching instability in electron beam formation systems of X-ray FELs is a recently discovered effect hampering beam instrumentation and FEL operation. The instability was observed in different facilities in infrared and visible wavelength ranges. In this paper we propose to use such an instability for generation of vacuum ultraviolet (VUV) and X-ray radiation. A typical longitudinal space charge amplifier (LSCA) consists of few amplification cascades (drift space plus chicane) with a short undulator behind the last cascade. If the amplifier starts up from the shot noise, the amplified density modulation has a wide band, on the order of unity. The bandwidth of the radiation within the central cone is given by inverse number of undulator periods. A wavelength compression could be an attractive option for LSCA since the process is broadband, and a high compression stability is not required. LSCA can be used as a cheap addition to the existing or planned short-wavelength FELs. In particular, it can produce the second color for a pump-probe experiment. It is also possible to generate attosecond pulses in the VUV and X-ray regimes. Some user experiments can profit from a relatively large bandwidth of the radiation, and this is easy to obtain in LSCA scheme. Finally, since the amplification mechanism is broadband and robust, LSCA can be an interesting alternative to self-amplified spontaneous emission free electron laser (SASE FEL) in the case of using laser-plasma accelerators as drivers of light sources.

  3. A simple ligation-based method to increase the information density in sequencing reactions used to deconvolute nucleic acid selections

    PubMed Central

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

    2008-01-01

    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

  4. The use of multiple displacement amplification to amplify complex DNA libraries

    PubMed Central

    Fullwood, Melissa J.; Tan, Jack J. S.; Ng, Patrick W. P.; Chiu, Kuo Ping; Liu, Jun; Wei, Chia Lin; Ruan, Yijun

    2008-01-01

    Complex libraries for genomic DNA and cDNA sequencing analyses are typically amplified using bacterial propagation. To reduce biases, large numbers of colonies are plated and scraped from solid-surface agar. This process is time consuming, tedious and limits scaling up. At the same time, multiple displacement amplification (MDA) has been recently developed as a method for in vitro amplification of DNA. However, MDA has no selection function for the removal of ligation multimers. We developed a novel method of briefly introducing ligation reactions into bacteria to select single insert DNA clones followed by MDA to amplify. We applied these methods to a Gene Identification Signatures with Paired-End diTags (GIS-PET) library, which is a complex transcriptome library created by pairing short tags from the 5′ and 3′ ends of cDNA fragments together, and demonstrated that this selection and amplification strategy is unbiased and efficient. PMID:18285362

  5. (Bio)molecular surface patterning by phototriggered oxime ligation.

    PubMed

    Pauloehrl, Thomas; Delaittre, Guillaume; Bruns, Michael; Meißler, Maria; Börner, Hans G; Bastmeyer, Martin; Barner-Kowollik, Christopher

    2012-09-03

    Making light work of ligation: A novel method utilizes light for oxime ligation chemistry. A quantitative, low-energy photodeprotection generates aldehyde, which subsequently reacts with aminooxy moieties. The spatial control allows patterning on surfaces with a fluoro marker and GRGSGR peptide, and can be imaged by time-of-flight secondary-ion mass spectrometry.

  6. 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.

    PubMed

    Yoshino, Yuki; Ishida, Masaharu; Horii, Akira

    2007-10-01

    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.

  7. Multiple pass laser amplifier system

    DOEpatents

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

    1977-01-01

    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.

  8. Improved-Bandwidth Transimpedance Amplifier

    NASA Technical Reports Server (NTRS)

    Chapsky, Jacob

    2009-01-01

    The widest available operational amplifier, with the best voltage and current noise characteristics, is considered for transimpedance amplifier (TIA) applications where wide bandwidth is required to handle fast rising input signals (as for time-of-flight measurement cases). The added amplifier inside the TIA feedback loop can be configured to have slightly lower voltage gain than the bandwidth reduction factor.

  9. A simple microfluidic assay for the detection of ligation product.

    PubMed

    Zhang, Lei; Wang, Jingjing; Roebelen, Johann; Tripathi, Anubhav

    2015-02-01

    We present a novel microfluidic-based approach to detect ligation products. The conformal specificity of ligases is used in various molecular assays to detect point mutations. Traditional methods of detecting ligation products include denaturing gel electrophoresis, sequence amplification, and melting curve analysis. Gel electrophoresis is a labor- and time-intensive process, while sequence amplification and melting curve analysis require instruments capable of accurate thermal ramping and sensitive optical detection. Microfluidics has been widely applied in genomics, proteomics, and cell cytometry to enable rapid and automated assays. We designed an assay that fluorogenically detects ligation products following a simple magnetic separation through a microfluidic channel. 100 nM of synthetic HIV-1 K103N minority mutant templates were successfully detected in 30 min. This simple and rapid method can be coupled with any ligation assay for the detection of ligation products.

  10. Irreversible sortase A-mediated ligation driven by diketopiperazine formation.

    PubMed

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

    2014-01-17

    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.

  11. Template-directed oligonucleotide ligation on hydroxylapatite

    NASA Technical Reports Server (NTRS)

    Acevedo, O. L.; Orgel, L. E.

    1986-01-01

    It has been suggested that the prebiotic synthesis of the precursors of biopolymers could have occurred on a solid surface such as that provided by clay or some other mineral. One such scheme envisages that growing polymers were localized by adsorption to a mineral surface where an activating agent or activated monomers were supplied continuously or cyclically. Here, it is reported that a sequence of reactions in which initially formed oligo(G)s are reactivated by conversion to phosphorimidazolides in the presence of poly(C) and then allowed to ligate is ideal, in that repeated cycles can be carried out on the surface of hydroxylapatite, whereas in the liquid phase the cycle could be achieved only with considerable difficulty.

  12. Endoscopic band ligation for colonic diverticular hemorrhage.

    PubMed

    Ishii, Naoki; Setoyama, Takeshi; Deshpande, Gautam A; Omata, Fumio; Matsuda, Michitaka; Suzuki, Shoko; Uemura, Masayo; Iizuka, Yusuke; Fukuda, Katsuyuki; Suzuki, Koyu; Fujita, Yoshiyuki

    2012-02-01

    The number of sample cases of colonic diverticular hemorrhage treated with endoscopic band ligation (EBL) has been small to date. To elucidate the safety and efficacy of EBL for colonic diverticular hemorrhage. Retrospective study. General hospital. A total of 29 patients with 31 colonic diverticula with stigmata of recent hemorrhage (SRH). Urgent colonoscopy was performed after bowel preparation. When diverticula with SRH were identified, marking with hemoclips was done near the diverticula. The endoscope was removed and reinserted after a band-ligator device was attached to the tip of endoscope. At first, EBL was attempted. In patients who could not be treated with EBL, epinephrine injection or endoscopic clipping was performed. Procedure time, rate of hemostasis and rebleeding, complications. The mean procedure time was 47 ± 19 minutes. EBL was successfully completed in 27 colonic diverticula (87%); except in 3 diverticula with a small orifice and large dome and 1 diverticula in which the orifice was too large. Early rebleeding after EBL occurred in 3 of 27 cases (11%). Although 2 cases of sigmoid rebleeding could be managed by repeat EBL or conservatively, right hemicolectomy was performed in 1 ascending diverticulum, in which the bleeding source was not identified on repeat colonoscopy. Scar formation at previously banded diverticula was identified in 7 of 11 patients who underwent follow-up colonoscopy. There were no complications after EBL in any of the patients. Retrospective study. EBL is a safe and effective treatment for colonic diverticular hemorrhage, and colonic diverticula resolve after EBL. Copyright © 2012 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  13. Robust detection and identification of multiple oomycetes and fungi in environmental samples by using a novel cleavable padlock probe-based ligation detection assay.

    PubMed

    van Doorn, R; Slawiak, M; Szemes, M; Dullemans, A M; Bonants, P; Kowalchuk, G A; Schoen, C D

    2009-06-01

    Simultaneous detection and identification of multiple pathogenic microorganisms in complex environmental samples are required in numerous diagnostic fields. Here, we describe the development of a novel, background-free ligation detection (LD) system using a single compound detector probe per target. The detector probes used, referred to as padlock probes (PLPs), are long oligonucleotides containing asymmetric target complementary regions at both their 5' and 3' ends which confer extremely specific target detection. Probes also incorporate a desthiobiotin moiety and an internal endonuclease IV cleavage site. DNA samples are PCR amplified, and the resulting products serve as potential targets for PLP ligation. Upon perfect target hybridization, the PLPs are circularized via enzymatic ligation, captured, and cleaved, allowing only the originally ligated PLPs to be visualized on a universal microarray. Unlike previous procedures, the probes themselves are not amplified, thereby allowing a simple PLP cleavage to yield a background-free assay. We designed and tested nine PLPs targeting several oomycetes and fungi. All of the probes specifically detected their corresponding targets and provided perfect discrimination against closely related nontarget organisms, yielding an assay sensitivity of 1 pg genomic DNA and a dynamic detection range of 10(4). A practical demonstration with samples collected from horticultural water circulation systems was performed to test the robustness of the newly developed multiplex assay. This novel LD system enables highly specific detection and identification of multiple pathogens over a wide range of target concentrations and should be easily adaptable to a variety of applications in environmental microbiology.

  14. Amplifying Electrochemical Indicators

    NASA Technical Reports Server (NTRS)

    Fan, Wenhong; Li, Jun; Han, Jie

    2004-01-01

    Dendrimeric reporter compounds have been invented for use in sensing and amplifying electrochemical signals from molecular recognition events that involve many chemical and biological entities. These reporter compounds can be formulated to target specific molecules or molecular recognition events. They can also be formulated to be, variously, hydrophilic or amphiphilic so that they are suitable for use at interfaces between (1) aqueous solutions and (2) electrodes connected to external signal-processing electronic circuits. The invention of these reporter compounds is expected to enable the development of highly miniaturized, low-power-consumption, relatively inexpensive, mass-producible sensor units for diverse applications.

  15. Amplified total internal reflection.

    PubMed

    Fan, J; Dogariu, A; Wang, L J

    2003-02-24

    Totally internal reflected beams can be amplified if the lowerindex medium has gain. We analyze the reflection and refraction of light, and analytically derive the expression for the Goos-Hänchen shifts of a Gaussian beam incident on a lower-index medium, both active and absorptive. We examine the energy flow and the Goos-Hänchen shifts for various cases. The analytical results are consistent with the numerical results. For the TE mode, the Goos-Hänchen shift for the transmitted beam is exactly half of that of the reflected beam, resulting in a "1/2" rule.

  16. REGENERATIVE TRANSISTOR AMPLIFIER

    DOEpatents

    Kabell, L.J.

    1958-11-25

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

  17. Efficient Ligation of the Schistosoma Hammerhead Ribozyme †

    PubMed Central

    Canny, Marella D.; Jucker, Fiona M.; Pardi, Arthur

    2011-01-01

    The hammerhead ribozyme from Schistosoma mansoni is the best characterized of the natural hammerhead ribozymes. Biophysical, biochemical, and structural studies have shown that the formation of the loop-loop tertiary interaction between stems I and II alters the global folding, cleavage kinetics, and conformation of the catalytic core of this hammerhead, leading to a ribozyme that is readily cleaved under physiological conditions. This study investigates the ligation kinetics and the internal equilibrium between cleavage and ligation for the Schistosoma hammerhead. Single turnover kinetic studies on a construct where the ribozyme cleaves and ligates substrate(s) in trans showed up to 23% ligation when starting from fully cleaved products. This was achieved by a ~2,000-fold increase in the rate of ligation compared to a minimal hammerhead without the loop-loop tertiary interaction, yielding an internal equilibrium that ranges from 2–3 at physiological Mg2+ ion concentrations (0.1 –1 mM). Thus, the natural Schistosoma hammerhead ribozyme is almost as efficient at ligation as it is at cleavage. The results here are consistent with a model where formation of the loop-loop tertiary interaction leads to a higher population of catalytically active molecules, and where formation of this tertiary interaction has a much larger effect on the ligation than the cleavage activity of the Schistosoma hammerhead ribozyme. PMID:17319693

  18. Universal Signal Conditioning Amplifier

    NASA Technical Reports Server (NTRS)

    Kinney, Frank

    1997-01-01

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

  19. DIAMOND AMPLIFIED PHOTOCATHODES.

    SciTech Connect

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

    2007-11-26

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

  20. Selective suppression of interleukin-12 induction after macrophage receptor ligation.

    PubMed

    Sutterwala, F S; Noel, G J; Clynes, R; Mosser, D M

    1997-06-02

    Interleukin (IL)-12 is a monocyte- and macrophage-derived cytokine that plays a crucial role in both the innate and the acquired immune response. In this study, we examined the effects that ligating specific macrophage receptors had on the induction of IL-12 by lipopolysaccharide (LPS). We report that ligation of the macrophage Fcgamma, complement, or scavenger receptors inhibited the induction of IL-12 by LPS. Both mRNA synthesis and protein secretion were diminished to near-undetectable levels following receptor ligation. Suppression was specific to IL-12 since IL-10 and tumor necrosis factor-alpha (TNF-alpha) production were not inhibited by ligating macrophage receptors. The results of several different experimental approaches suggest that IL-12 downregulation was due to extracellular calcium influxes that resulted from receptor ligation. First, preventing extracellular calcium influxes, by performing the assays in EGTA, abrogated FcgammaR-mediated IL-12(p40) mRNA suppression. Second, exposure of macrophages to the calcium ionophores, ionomycin or A23187, mimicked receptor ligation and inhibited IL-12(p40) mRNA induction by LPS. Finally, bone marrow-derived macrophages from FcR gamma chain-deficient mice, which fail to flux calcium after receptor ligation, failed to inhibit IL-12(p40) mRNA induction. These results indicate that the calcium influxes that occur as a result of receptor ligation are responsible for inhibiting the induction of IL-12 by LPS. Hence, the ligation of phagocytic receptors on macrophages can lead to a dramatic decrease in IL-12 induction. This downregulation may be a way of limiting proinflammatory responses of macrophages to extracellular pathogens, or suppressing the development of cell-mediated immunity to intracellular pathogens.

  1. Convergent synthesis of proteins by kinetically controlled ligation

    DOEpatents

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

    2010-03-09

    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.

  2. Chemical ligation of oligonucleotides using an electrophilic phosphorothioester

    PubMed Central

    Oikawa, Ryota; Hayakawa, Mayu; Takamori, Shono; Kimura, Yasuaki; Abe, Naoko; Tsuji, Genichiro; Matsuda, Akira; Shuto, Satoshi; Ito, Yoshihiro

    2017-01-01

    Abstract We developed a new approach for chemical ligation of oligonucleotides using the electrophilic phosphorothioester (EPT) group. A nucleophilic phosphorothioate group on oligonucleotides was converted into the EPT group by treatment with Sanger's reagent (1-fluoro-2,4-dinitrobenzene). EPT oligonucleotides can be isolated, stored frozen, and used for the ligation reaction. The reaction of the EPT oligonucleotide and an amino-modified oligonucleotide took place without any extra reagents at pH 7.0–8.0 at room temperature, and resulted in a ligation product with a phosphoramidate bond with a 39–85% yield. This method has potential uses in biotechnology and chemical biology. PMID:28520986

  3. Analysis of Genes, Transcripts, and Proteins via DNA Ligation

    NASA Astrophysics Data System (ADS)

    Conze, Tim; Shetye, Alysha; Tanaka, Yuki; Gu, Jijuan; Larsson, Chatarina; Göransson, Jenny; Tavoosidana, Gholamreza; Söderberg, Ola; Nilsson, Mats; Landegren, Ulf

    2009-07-01

    Analytical reactions in which short DNA strands are used in combination with DNA ligases have proven useful for measuring, decoding, and locating most classes of macromolecules. Given the need to accumulate large amounts of precise molecular information from biological systems in research and in diagnostics, ligation reactions will continue to offer valuable strategies for advanced analytical reactions. Here, we provide a basis for further development of methods by reviewing the history of analytical ligation reactions, discussing the properties of ligation reactions that render them suitable for engineering novel assays, describing a wide range of successful ligase-based assays, and briefly considering future directions.

  4. Formatting and ligating biopolymers using adjustable nanoconfinement

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    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.

  5. Amplified wind turbine apparatus

    NASA Technical Reports Server (NTRS)

    Hein, L. A.; Myers, W. N. (Inventor)

    1982-01-01

    An invention related to the utilization of wind energy and increasing the effects thereof for power generation is described. Amplified wind turbine apparatus is disclosed wherein ambient inlet air is prerotated in a first air rotation chamber having a high pressure profile increasing the turbulence and Reynolds number thereof. A second rotation chamber adjacent and downstream of the turbine has a low pressure core profile whereby flow across the turbine is accelerated and thereafter exits the turbine apparatus through a draft anti-interference device. Interference with ambient winds at the outlet of the turbine apparatus is thus eliminated. Pivotable vanes controlled in response to prevailing wind direction admit air to the chambers and aid in imparting rotation. A central core may be utilized for creating the desired pressure profile in the chamber.

  6. Nanoscale electromechanical parametric amplifier

    SciTech Connect

    Aleman, Benjamin Jose; Zettl, Alexander

    2016-09-20

    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.

  7. The microstrip SQUID amplifier

    NASA Astrophysics Data System (ADS)

    Therrien, Roy

    A Superconducting Quantum Interference Devices (SQUIDS) can operate at frequencies up to several GHz and can be cooled to less than 100 mK. Such characteristics make the SQUID---a flux-to-voltage transducer---an excellent candidate for use as a low-noise rf amplifier. Coupling of input signals of frequencies larger than 200 MHz, however, has been limited by the parasitic capacitance between the input coil and SQUID body. We present experimental observations of a do SQUID-based rf amplifier which circumvents this problem by incorporating the input coil as a microstrip resonator. The microstrip input configuration uses the capacitance and inductance of the input coil to form a resonant cavity capable of operating up to several GHz. The input signal is applied between the SQUID body and one end of the input coil, while the other end of the coil is left open. We present data from microstrip SQUID amplifiers with gains of up to 22 dB at 900 MHz. In order to understand the gain and input impedance of the microstrip SQUID in greater detail, we made and studied a 1:190 scale analog patterned on a double-sided printed circuit board consisting of copper deposited on a kapton sheet. The measured input impedance of the analog SQUID is successfully modeled by describing the microstrip input as a low-loss transmission line. When operated with the slit in the copper washer ground plane shorted, the input coil behaves exactly like a linear resonator with the resonant frequency given by f = 1/2ℓ(L 0C0)1/2, where L0 and C0 are the inductance and capacitance per unit length and ℓ is the coil length. With the slit in the washer left open, the inductance of the input coil is significantly altered in a manner partially consistent with the Ketchen-Jaycox model in which the reflected inductance of the input coil is Li = n2L, where L is the inductance of the washer loop and n is the number of turns in the coil. We present input impedance measurements on microstrip SQUIDs cooled to 4

  8. Open Surgical Management of Hypogastric Artery during Aortic Surgery: Ligate or Not Ligate?

    PubMed

    Marconi, Michele; Ceragioli, Sabrina; Mocellin, Davide M; Alberti, Aldo; Tomei, Francesca; Adami, Daniele; Berchiolli, Raffaella N; Ferrari, Mauro

    2015-01-01

    Abdominal aortic aneurysm (AAA) is associated with 43% of cases with common iliac artery aneurysms and an extension of prosthetic replacement distal to the iliac bifurcation is needed. The decision about preserving the hypogastric artery (HA) is a source of discussion, in particular when only one HA is interested. The low risk of pelvic ischemia, even if existing, has to be compared with the greater technical difficulty of the vascular reconstruction. The aim of this study is to evaluate retrospectively the perioperative results in patients who underwent ligation or reconstruction of the HA during open surgical procedures for AAA. Over a period of 11 years (January 2002 to December 2012), 1,487 patients were treated electively for AAA. In 235 cases (15.8%), the aneurysm involved the iliac bifurcation with need to extend distally the prosthetic reconstruction; among them, 63 patients were subjected to HA ligation (26.8%, group 1) and 172 to HA bypass (73.2%, group 2). Indication for ligation was the presence of extended HA aneurysm in 34 cases (54%) and heavy calcification of HA in 29 (46%). Perioperative mortality and morbidity rates were, respectively, 1.6% (1/63) and 7.9% (5/63) in group 1 and 1.2% (2/172) and 6.4% (11/172) in group 2 (P = 0.902 and 0.689). The incidence of buttock claudication was significantly higher in group 1 (6/63, 9.5% vs. 4/172, 2.3% P = 0.025), while there were no significant differences in other complications of pelvic ischemia. In group 2, higher intraoperative blood loss (754 ± 721 vs. 996 ± 608 mL, P = 0.011), longer operating time (283.2 ± 104.7 vs. 302 ± 109 min, P = 0.053), and longer postoperative length of stay (PLOS) (5.8 ± 2.2 vs. 6.7 ± 3.6 days, P = 0.049) occurred. HA bypass during open surgery for AAA is a safe procedure. If compared with ligation, it reduces the risk of buttock claudication without increasing perioperative morbidity and mortality. However, the increased complexity of the

  9. Analyzing ligation mixtures using a PCR based method

    PubMed Central

    Wikel, Stephen K.

    2005-01-01

    We have developed a simple and effective method (Lig-PCR) for monitoring ligation reactions using PCR and primers that are common to many cloning vectors. Ligation mixtures can directly be used as templates and the results can be analyzed by conventional gel electrophoresis. The PCR products are representative of the recombinant molecules created during ligation and the corresponding transformants. Orientation of inserts can also be determined using an internal primer. The usefulness of this method has been demonstrated using ligation mixtures of two cDNA’s derived from the salivary glands of Aedes aegypti mosquitoes. The method described here is sensitive and easy to perform compared to currently available methods. PMID:16136227

  10. Serine/threonine ligation for the chemical synthesis of proteins.

    PubMed

    Lee, Chi Lung; Li, Xuechen

    2014-10-01

    Advances in the development of efficient peptide ligation methods have enabled the total synthesis of complex proteins to be successfully undertaken. Recently, a Ser/Thr ligation has emerged as a new tool in synthetic protein chemistry. The chemoselective reaction between an N-terminal serine or threonine of an unprotected peptide segment and a C-terminal salicylaldehyde ester of another unprotected peptide segment gives rise to an N,O-benzylidene acetal linked product, which upon acidolysis produces a native peptide bond at the site of ligation. Ser/Thr ligation has been used for the synthesis of the human erythrocyte acylphosphatase protein and MUC1 glycopeptide segments, semisynthesis of peptoid/PEG-RNase S protein hybrids, and cyclic peptide synthesis including cyclic tetrapeptides, cyclomontanin B, yunnanin C, mahafacyclin B, and daptomycin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Cross-ligation and exchange reactions catalyzed by hairpin ribozymes.

    PubMed Central

    Komatsu, Y; Koizumi, M; Sekiguchi, A; Ohtsuka, E

    1993-01-01

    The negative strand of the satellite RNA of tobacco ringspot virus (sTobRV(-)) contains a hairpin catalytic domain that shows self-cleavage and self-ligation activities in the presence of magnesium ions. We describe here that the minimal catalytic domain can catalyze a cross-ligation reaction between two kinds of substrates in trans. The cross-ligated product increased when the reaction temperature was decreased during the reaction from 37 degrees C to 4 degrees C. A two-stranded hairpin ribozyme, divided into two fragments between G45 and U46 in a hairpin loop, showed higher ligation activity than the nondivided ribozyme. The two stranded ribozyme also catalyzed an exchange reaction of the 3'-portion of the cleavage site. Images PMID:8441626

  12. Hairpin ribozyme-catalyzed ligation in water-alcohol solutions.

    PubMed

    Vlassov, Alexander V; Johnston, Brian H; Kazakov, Sergei A

    2005-12-01

    The hairpin ribozyme (HPR) is a naturally existing RNA that catalyzes site-specific RNA cleavage and ligation. At 37 degrees C and in the presence of divalent metal ions (M(2+)), the HPR efficiently cleaves RNA substrates in trans. Here, we show that the HPR can catalyze efficient M(2+)-independent ligation in trans in aqueous solutions containing any of several alcohols, including methanol, ethanol, and isopropanol, and millimolar concentrations of monovalent cations. Ligation proceeds most efficiently in 60% isopropanol at 37 degrees C, whereas the reverse (cleavage) reaction is negligible under these conditions. We suggest that dehydration of the RNA is the key factor promoting HPR activity in water- alcohol solutions. Alcohol-induced ribozyme ligation may have practical applications.

  13. A Photo-Triggered Traceless Staudinger-Bertozzi Ligation Reaction.

    PubMed

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

    2016-08-08

    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.

  14. Reflex ring laser amplifier system

    DOEpatents

    Summers, Mark A.

    1985-01-01

    A laser pulse is injected into an unstable ring resonator-amplifier structure. Inside this resonator the laser pulse is amplified, spatially filtered and magnified. The laser pulse is recirculated in the resonator, being amplified, filtered and magnified on each pass. The magnification is chosen so that the beam passes through the amplifier in concentric non-overlapping regions similar to a single pass MOPA. After a number of passes around the ring resonator the laser pulse is spatially large enough to exit the ring resonator system by passing around an output mirror.

  15. Wavelength tunable alexandrite regenerative amplifier

    SciTech Connect

    Harter, D.J.; Bado, P.

    1988-11-01

    We describe a wavelength tunable alexandrite regenerative amplifier which is used to amplify nanosecond slices from a single-frequency cw dye laser or 50-ps pulses emitted by a diode laser to energies in the 10-mJ range. The amplified 5-ns slices generated by the cw-pumped line narrowed dye laser are Fourier transform limited. The 50-ps pulses emitted by a gain-switched diode laser are amplified by more than 10 orders of magnitude in a single stage.

  16. Optical Amplifier for Space Applications

    NASA Technical Reports Server (NTRS)

    Fork, Richard L.; Cole, Spencer T.; Gamble, Lisa J.; Diffey, William M.; Keys, Andrew S.

    1999-01-01

    We describe an optical amplifier designed to amplify a spatially sampled component of an optical wavefront to kilowatt average power. The goal is means for implementing a strategy of spatially segmenting a large aperture wavefront, amplifying the individual segments, maintaining the phase coherence of the segments by active means, and imaging the resultant amplified coherent field. Applications of interest are the transmission of space solar power over multi-megameter distances, as to distant spacecraft, or to remote sites with no preexisting power grid.

  17. [Rubber band ligation in treatment of hemorrhoids: our experience].

    PubMed

    Gaj, F; Biviano, I; Sportelli, G; Candeloro, L

    2015-01-01

    Hemorrhoids are a very common condition. The treatment depends upon persistence and severity of symptoms. For hemorrhoids of II and III grade the rubber band ligation may be therapeutic. Our aim is to report the outcomes of rubber band ligation of hemorrhoids, with a follow up of 6 months. A total of 50 patients underwent rubber band ligation for symptomatic hemorrhoids (grade II and III) without prolapse, between June 2012 and June 2014. All patients underwent plug test to rule out presence of rectal mucosal prolapse and were classified according to PATE classification (1). Each hemorrhoid was ligated with one rubber band through a ligator. All patients were evaluated immediately at the end of the procedure, after ten days and six months after the treatment. Patient's demographic and operative data were collected and analyzed. The mean patients age was 47.6±12.3 years (range 24-72). All procedures were performed without complications. Before rubber band ligation, 42 patients had rectal bleeding, 38 had perineal discomfort and 27 had itching. Ten days after the treatment, 12 patients presented self-limited rectal bleeding, but 10 of these had more hemorrhoids and underwent a second rubber band ligation. No patients complained perineal discomfort, and 8 patients had itching; 78% and 16% of patients respectively, experienced feeling of a foreign body inside the canal anal and anal pain. After 6 months, only 13 patients were occasionally symptomatic: 4 patients had rectal bleeding, 2 had perineal discomfort and 4 had itching. Three more patients presented both perineal discomfort and hitching. None had the feeling of a foreign body in anal canal or anal pain. Rubber band ligation is an efficacious, cost-effective and simple treatment for the second and third degree hemorrhoids without rectal mucosal prolapsed. In our hands, no severe complications developed and minor complications could be handled with ease.

  18. X-ray snapshots for metalloporphyrin axial ligation

    SciTech Connect

    Chen, L. X.; Zhang, X.; Wasinger, E. C.; Lockard, J. V.; Stickrath, A. B.; Mara, M. W.; Attenkofer, K.; Jennings, G.; Smolentsev, G.; Soldatov, A.

    2010-01-01

    Axial ligation mechanisms of a metalloporphyrin, nickel(II) tetramesitylporphyrin (NiTMP), were investigated by static and transient X-ray absorption spectroscopy at Ni K-edge (8.333 keV). A surprisingly broad (i.e. {approx}1.4 eV) linewidth for the 1s {yields} 3d{sub x2-y2} transition in the ground state was attributed to strong geometry dependent 3d molecular orbital (MO) energies due to coexisting conformers in solution. The broad distribution of 3d MO energy levels enables transient degeneracy of the 3d{sub z2} and 3d{sub x2-y2} MOs to produce a temporary vacancy in the 3d{sub z2} MO which favors axial ligation. Photoexcitation also induces the vacancy in the 3d{sub z2} MO, leading to a more than two-fold enhancement in the axial ligated species. Therefore, a unified axial ligation mechanism for both the ground and excited state is proposed based on the elucidation of the excited state structural dynamics, which will have a broad impact in understanding and controlling axial ligation in enzymatic reactions and molecular catalysis involving transient axial ligation.

  19. Irritable bowel syndrome in women undergoing hysterectomy and tubular ligation

    PubMed Central

    Khoshbaten, Manouchehr; Melli, Manigheh Syah; Fattahi, Monireh Jabar; Sharifi, Nasrin; Mostafavi, Seyed Abolfazl

    2011-01-01

    Aim The aim of this study was to assess the incidence of irritable bowel syndrome in women undergoing hysterectomy and tubular ligation. Background The results of previous studies have shown an increased incidence of irritable bowel syndrome after gynecological surgeries. Patients and methods Participants were patients of Alzahra and Taleghani University hospitals in Tabriz. One hundred and seventy two women without gastrointestinal symptoms or a diagnosis of the irritable bowel syndrome underwent tubular ligation and 164 women underwent hysterectomy. Patients were assessed every 3 month after hysterectomy and tubular ligation for 12 months. Irritable bowel syndrome was diagnosed by a questionnaire based on Rome II criteria. Results During 12 months after surgeries, 19 (11%) patients in tubular ligation group and 19 (11%) in hysterectomy group had abdominal pain with at least two symptoms of irritable bowel syndrome. Irritable bowel syndrome was diagnosed in 9 (5%) patients in the tubular ligation and 13 (8%) patients in hysterectomy groups (P>0.05). In both studied groups, the most prevalent symptoms along with abdominal pain were chronic constipation and abnormal bowel movement and the least prevalent were diarrhea and passage of mucus. Conclusion These results suggest that gynecological surgeries (tubular ligation and hysterectomy) may predispose to the development of the irritable bowel syndrome. PMID:24834172

  20. Rubber band ligation of hemorrhoids: A guide for complications

    PubMed Central

    Albuquerque, Andreia

    2016-01-01

    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

  1. Ligation with nucleic acid sequence-based amplification.

    PubMed

    Ong, Carmichael; Tai, Warren; Sarma, Aartik; Opal, Steven M; Artenstein, Andrew W; Tripathi, Anubhav

    2012-01-01

    This work presents a novel method for detecting nucleic acid targets using a ligation step along with an isothermal, exponential amplification step. We use an engineered ssDNA with two variable regions on the ends, allowing us to design the probe for optimal reaction kinetics and primer binding. This two-part probe is ligated by T4 DNA Ligase only when both parts bind adjacently to the target. The assay demonstrates that the expected 72-nt RNA product appears only when the synthetic target, T4 ligase, and both probe fragments are present during the ligation step. An extraneous 38-nt RNA product also appears due to linear amplification of unligated probe (P3), but its presence does not cause a false-positive result. In addition, 40 mmol/L KCl in the final amplification mix was found to be optimal. It was also found that increasing P5 in excess of P3 helped with ligation and reduced the extraneous 38-nt RNA product. The assay was also tested with a single nucleotide polymorphism target, changing one base at the ligation site. The assay was able to yield a negative signal despite only a single-base change. Finally, using P3 and P5 with longer binding sites results in increased overall sensitivity of the reaction, showing that increasing ligation efficiency can improve the assay overall. We believe that this method can be used effectively for a number of diagnostic assays.

  2. Rapamycin delays salivary gland atrophy following ductal ligation.

    PubMed

    Bozorgi, S S; Proctor, G B; Carpenter, G H

    2014-03-27

    Salivary gland atrophy is a frequent consequence of head and neck cancer irradiation therapy but can potentially be regulated through the mammalian target of rapamycin (mTOR). Excretory duct ligation of the mouse submandibular gland provokes severe glandular atrophy causing activation of mTOR. This study aims to discover the effects of blocking mTOR signaling in ligation-induced atrophic salivary glands. Following 1 week of unilateral submandibular excretory duct ligation: gland weights were significantly reduced, 4E-BP1 and S6rp were activated, and tissue morphology revealed typical signs of atrophy. However, 3 days following ligation with rapamycin treatment, a selective mTOR inhibitor, gland weights were maintained, 4E-BP1 and S6rp phosphorylation was inhibited, and there were morphological signs of recovery from atrophy. However, following 5 and 7 days of ligation and rapamycin treatment, glands expressed active mTOR and showed signs of considerable atrophy. This evidence suggests that inhibition of mTOR by rapamycin delays ligation-induced atrophy of salivary glands.

  3. Comparison of Doppler-guided haemorrhoidal artery ligation without mucopexy and rubber band ligation for haemorrhoids.

    PubMed

    Pol, Robert A; van der Zwet, Wil C; Kaijser, Mirjam; Schattenkerk, Marinus Eeftinck; Eddes, Eric-Hans

    2011-12-01

    Recurrences after Doppler-guided haemorrhoidal artery ligation (DG-HAL) tend to occur in patients with concurrent mucosal prolapse. We retrospectively compared the results of DG-HAL and rubber band ligation (RBL) for the treatment of haemorrhoidal disease. From 2005 to 2009, all patients who underwent either a DG-HAL procedure or RBL were selected. Follow-up was done by telephone using a standardised questionnaire survey to assess patient satisfaction and complaints. When recurrent disease was suspected, patients revisited the clinic for further examination and treatment. A total of 239 DG-HAL patients and 47 RBL patients were analysed. Sixty-seven percent in the DG-HAL group and 79% in the RBL group had an improvement in symptoms after one treatment (p=0.22). Forty-six DG-HAL patients (19%) needed a second procedure versus three patients (6%) in the RBL group (p<0.05). Cox regression analysis showed a significant difference in disease recurrence in favour of RBL (hazard ratio (HR) 3.71, 95% confidence interval (CI) 1.13-12.2). Patients in the DG-HAL group with recurrent haemorrhoids had a higher incidence of mucosal prolapse. DG-HAL seems very effective in treating lower-grade haemorrhoids. In more advanced disease, recurrence occurs due to persisting mucosal prolapse. RBL seems much more effective in reducing the prolapse and the chance of recurrence. Copyright © 2011 Arab Journal of Gastroenterology. Published by Elsevier Ltd. All rights reserved.

  4. Deflection amplifier for image dissectors

    NASA Technical Reports Server (NTRS)

    Salomon, P. M.

    1977-01-01

    Balanced symmetrical y-axis amplifier uses zener-diode level shifting to interface operational amplifiers to high voltage bipolar output stages. Nominal voltage transfer characteristic is 40 differential output volts per input volt; bandwidth, between -3-dB points, is approximately 8 kHz; loop gain is nominally 89 dB with closed loop gain of 26 dB.

  5. Suicide Risk: Amplifiers and Attenuators.

    ERIC Educational Resources Information Center

    Plutchik, Robert; Van Praag, Herman M.

    1994-01-01

    Attempts to integrate findings on correlates of suicide and violent risk in terms of a theory called a two-stage model of countervailing forces, which assumes that the strength of aggressive impulses is modified by amplifiers and attenuators. The vectorial interaction of amplifiers and attenuators creates an unstable equilibrium making prediction…

  6. Improved radiographic image amplifier panel

    NASA Technical Reports Server (NTRS)

    Brown, R. L., Sr.

    1968-01-01

    Layered image amplifier for radiographic /X ray and gamma ray/ applications, combines very high radiation sensitivity with fast image buildup and erasure capabilities by adding a layer of material that is both photoconductive and light-emitting to basic image amplifier and cascading this assembly with a modified Thorne panel.

  7. Suicide Risk: Amplifiers and Attenuators.

    ERIC Educational Resources Information Center

    Plutchik, Robert; Van Praag, Herman M.

    1994-01-01

    Attempts to integrate findings on correlates of suicide and violent risk in terms of a theory called a two-stage model of countervailing forces, which assumes that the strength of aggressive impulses is modified by amplifiers and attenuators. The vectorial interaction of amplifiers and attenuators creates an unstable equilibrium making prediction…

  8. DIAMOND AMPLIFIER FOR PHOTOCATHODES.

    SciTech Connect

    RAO,T.; BEN-ZVI,I.; BURRILL,A.; CHANG,X.; HULBERT,S.; JOHNSON,P.D.; KEWISCH,J.

    2004-06-21

    We report a new approach to the generation of high-current, high-brightness electron beams. Primary electrons are produced by a photocathode (or other means) and are accelerated to a few thousand electron-volts, then strike a specially prepared diamond window. The large Secondary Electron Yield (SEY) provides a multiplication of the number of electrons by about two orders of magnitude. The secondary electrons drift through the diamond under an electric field and emerge into the accelerating proper of the ''gun'' through a Negative Electron Affinity surface of the diamond. The advantages of the new approach include the following: (1) Reduction of the number of primary electrons by the large SEY, i.e. a very low laser power in a photocathode producing the primaries. (2) Low thermal emittance due to the NEA surface and the rapid thermalization of the electrons. (3) Protection of the cathode from possible contamination from the gun, allowing the use of large quantum efficiency but sensitive cathodes. (4) Protection of the gun from possible contamination by the cathode, allowing the use of superconducting gun cavities. (5) Production of high average currents, up to ampere class. (6) Encapsulated design, making the ''load-lock'' systems unnecessary. This paper presents the criteria that need to be taken into account in designing the amplifier.

  9. A ribozyme that ligates RNA to protein.

    PubMed

    Baskerville, Scott; Bartel, David P

    2002-07-09

    We have used a combination of in vitro selection and rational design to generate ribozymes that form a stable phosphoamide bond between the 5' terminus of an RNA and a specific polypeptide. This reaction differs from that of previously identified ribozymes, although the product is analogous to the enzyme-nucleotidyl intermediates isolated during the reactions of certain proteinaceous enzymes, such as guanyltransferase, DNA ligase, and RNA ligase. Comparative sequence analysis of the isolated ribozymes revealed that they share a compact secondary structure containing six stems arranged in a four-helix junction and branched pseudoknot. An optimized version of the ribozyme reacts with substrate-fusion proteins, allowing it to be used to attach RNA tags to proteins both in vitro and within bacterial cells, suggesting a simple way to tag a specific protein with amplifiable information.

  10. Tubal ligation and survival of ovarian cancer patients.

    PubMed

    Zhang, Min; Holman, C D'Arcy J

    2012-01-01

    The aim of the present study was to investigate associations between ovarian cancer survival and reproductive, gynecological and hormone factors. A prospective follow-up study was conducted in the Southeast of China. The cohort comprised 202 patients with histopathologically confirmed epithelial ovarian cancer who were enrolled during 1999-2000 and followed-up for 5years subsequently. One hundred and ninety five (96.5%) of the cohort or their close relatives were traced. Information was obtained on reproductive, gynecological and hormone factors prior to diagnosis, actual survival time and number of deaths. Cox proportional models were used to estimate mortality hazard ratios (HR) and associated 95% confidence intervals (CI) for tubal ligation, adjusting for age at diagnosis, body mass index (BMI), menopausal status, International Federation of Gynaecology and Obstetrics (FIGO) stage, histological grade of differentiation, cytology of ascites, and chemotherapy status. The HR was significantly increased and survival was worse in ovarian cancer patients with a previous tubal ligation, but not with any other reproductive, gynecological and hormone factor. Only 21 (38.9%) of 54 patients who had tubal ligation survived to the time of interview, in contrast to 95 women (67.4%) still alive among the 141 women without tubal ligation (P<0.001). Compared to the patients who had no tubal ligation, the adjusted HR was 1.62 (95% CI 1.01-2.59; P=0.04) for those who had tubal ligation. There was no association with age at menarche, menopausal status, parity, breastfeeding, hormone replacement therapy, oral contraceptive use, and hysterectomy. Previous tubal ligation was an independently adverse prognostic factor for epithelial ovarian cancer survival. Further studies that examine the relationship are warranted to confirm these results. © 2011 The Authors. Journal of Obstetrics and Gynaecology Research © 2011 Japan Society of Obstetrics and Gynecology.

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

    PubMed Central

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

    2010-01-01

    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 was considered significant. RBL had the advantages of being an OPD procedure requiring no anesthesia and was attended by significantly lesser postoperative recumbency (P < 0.001 ) and significantly lesser pain (P < 0.005 on day 1) as compared to KSL. However, Group II (KSL) scored better in terms of treatment outcome. In Group II, there was significantly high (P < 0.05) patient satisfaction index as compared to Group I. Group II reported 100% 'cure' (absence of hemorrhoidal masses even on proctoscopy) of internal hemorrhoidal prolapse as against 80

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

    PubMed

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

    2010-04-01

    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 was considered significant. RBL had the advantages of being an OPD procedure requiring no anesthesia and was attended by significantly lesser postoperative recumbency (P < 0.001 ) and significantly lesser pain (P < 0.005 on day 1) as compared to KSL. However, Group II (KSL) scored better in terms of treatment outcome. In Group II, there was significantly high (P < 0.05) patient satisfaction index as compared to Group I. Group II reported 100% 'cure' (absence of hemorrhoidal masses even on proctoscopy) of internal hemorrhoidal prolapse as against 80

  13. Capacities of quantum amplifier channels

    NASA Astrophysics Data System (ADS)

    Qi, Haoyu; Wilde, Mark M.

    2017-01-01

    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.

  14. Ectopic tubal pregnancy after hysterectomy and tubal ligation.

    PubMed

    Rosa, Marilin; Mohammadi, Amir; Monteiro, Carmela

    2009-01-01

    Posthysterectomy ectopic pregnancy is an unusual condition that may present soon after hysterectomy or several years later. Similarly, although tubal ligation is a widespread method of contraception, tubal pregnancy after tubal ligation is not common either. If any of these conditions are rare, having an ectopic pregnancy after hysterectomy and tubal ligation is even more infrequent and only one of such cases was found in our review of the literature. We describe the case of a 35-year-old patient, with history of bilateral tubal ligation and vaginal hysterectomy that looked for medical attention due to abdominal pain. A pregnancy test was positive and a transvaginal ultrasound demonstrated the presence of a gestational sac at the vaginal cuff, adjacent to the ovary. An exploratory laparotomy showed a ruptured ectopic pregnancy located in the distal portion of the left fallopian tube. The occurrence of an ectopic pregnancy several years following tubal ligation and vaginal hysterectomy is a rare phenomenon that appears to be secondary to a fistulous connection into the peritoneal cavity.

  15. Laser Amplifier Developments at Mercury

    DTIC Science & Technology

    1993-06-01

    particularly foil lifetime, with no degradation in pumping. Mercury Amplifier 2 (A2 or Pluto ) is a downsized version of the Aurora Large Aperture Module (LAM...everywhere above the 4.5% cm-I required. Modifications to Pluto (Amplifier 2) The second amplifier, Pluto , was constructed by modifying Aurora’s...discharge the PFLs into matched resistors when the output switches failed to fire. lJ Figure 3. The diode of Pluto has a 40-cm high by 200-cm long

  16. New chemistries for chemoselective peptide ligations and the total synthesis of proteins.

    PubMed

    Harmand, Thibault J R; Murar, Claudia E; Bode, Jeffrey W

    2014-10-01

    The identification of fast, chemoselective bond-forming reactions is one of the major contemporary challenges in chemistry. The requirements of the native chemical ligation - an N-terminal cysteine and C-terminal thioesters - have encouraged a search for alternative amide-forming ligation reactions. Among successful alternatives to native chemical ligation, are the α-ketoacid-hydroxylamine ligation with 5-oxaproline and, serine/threonine ligation, and potassium acyltrifluoroborate (KAT) ligation. In addition, the KAT ligation, along with the non-amide forming alkyne-azide ligation, is very useful for synthetic conjugations. All of these recent ligation methods were applied to synthesize different proteins, and have allowed chemists to incorporate unnatural amino acids, or to modify the peptide backbone. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. High-Common-Mode-Rejection Differential Amplifier

    NASA Technical Reports Server (NTRS)

    Lukens, F. E.

    1984-01-01

    High-common-mode-rejection differential amplifier amplifies low-level signals in presence of high frequency noise. Amplifier used in power system requiring current monitoring on high side of high-voltage powerline.

  18. Enhanced performance CCD output amplifier

    DOEpatents

    Dunham, Mark E.; Morley, David W.

    1996-01-01

    A low-noise FET amplifier is connected to amplify output charge from a che coupled device (CCD). The FET has its gate connected to the CCD in common source configuration for receiving the output charge signal from the CCD and output an intermediate signal at a drain of the FET. An intermediate amplifier is connected to the drain of the FET for receiving the intermediate signal and outputting a low-noise signal functionally related to the output charge signal from the CCD. The amplifier is preferably connected as a virtual ground to the FET drain. The inherent shunt capacitance of the FET is selected to be at least equal to the sum of the remaining capacitances.

  19. New Packaging for Amplifier Slabs

    SciTech Connect

    Riley, M.; Thorsness, C.; Suratwala, T.; Steele, R.; Rogowski, G.

    2015-03-18

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

  20. A single supply biopotential amplifier.

    PubMed

    Spinelli, E M; Martinez, N H; Mayosky, M A

    2001-04-01

    A biopotential amplifier for single supply operation is presented. It uses a Driven Right Leg Circuit (DRL) to drive the patient's body to a DC common mode voltage, centering biopotential signals with respect to the amplifier's input voltage range. This scheme ensures proper range operation when a single power supply is used. The circuit described is especially suited for low consumption, battery-powered applications, requiring a single battery and avoiding switching voltage inverters to achieve dual supplies. The generic circuit is described and, as an example, a biopotential amplifier with a gain of 60 dB and a DC input range of +/-200 mV was implemented using low power operational amplifiers. A Common Mode Rejection Ratio (CMRR) of 126 dB at 50 Hz was achieved without trimming.

  1. Characterization of SLUG microwave amplifiers

    NASA Astrophysics Data System (ADS)

    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.

    2015-03-01

    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. RNA-Catalyzed RNA Ligation on an External RNA Template

    NASA Technical Reports Server (NTRS)

    McGinness, Kathleen E.; Joyce, Gerald F.

    2002-01-01

    Variants of the hc ligase ribozyme, which catalyzes ligation of the 3' end of an RNA substrate to the 5' end of the ribozyme, were utilized to evolve a ribozyme that catalyzes ligation reactions on an external RNA template. The evolved ribozyme catalyzes the joining of an oligonucleotide 3'-hydroxyl to the 5'-triphosphate of an RNA hairpin molecule. The ribozyme can also utilize various substrate sequences, demonstrating a largely sequence-independent mechanism for substrate recognition. The ribozyme also carries out the ligation of two oligonucleotides that are bound at adjacent positions on a complementary template. Finally, it catalyzes addition of mononucleoside '5-triphosphates onto the '3 end of an oligonucleotide primer in a template-dependent manner. The development of ribozymes that catalyze polymerase-type reactions contributes to the notion that an RNA world could have existed during the early history of life on Earth.

  3. Splint ligation of RNA with T4 DNA ligase

    PubMed Central

    Kershaw, Christopher J.; O’Keefe, Raymond T.

    2014-01-01

    Splint ligation of RNA, whereby specific RNA molecules are ligated together, can be carried out using T4 DNA ligase and a bridging DNA oligonucleotide complementary to the RNAs. This method takes advantage of the property of T4 DNA ligase to join RNA molecules when they are in an RNA:DNA hybrid. Splint ligation is a useful tool for the introduction of modified nucleotides into RNA molecules, insertion of a radiolabel into a specific position within an RNA and for the assembly of smaller synthetic RNAs into longer RNA molecules. Such modifications enable a wide range of experiments to be carried out with the modified RNA including structural studies, co-immunoprecipitations, and the ability to map sites of RNA:RNA and RNA:protein interactions. PMID:23065567

  4. Template-Directed Ligation of Peptides to Oligonucleotides

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

    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.

  5. Development of an Improved Animal Model of Overactive Bladder: Transperineal Ligation versus Transperitoneal Ligation in Male Rats

    PubMed Central

    Kim, Woo Hyun; Bae, Woong Jin; Park, Jung Woo; Choi, Jin Bong; Kim, Su Jin; Cho, Hyuk Jin; Ha, U Syn; Hong, Sung Hoo; Lee, Ji Youl; Hwang, Sung Yeoun

    2016-01-01

    Purpose We compared a transperineal ligation model and a transperitoneal ligation model in male rats to determine which animal model of overactive bladder (OAB) was more useful based on cystometrography, estimations of oxidative stress, and measurements of pro-inflammatory cytokine levels. Materials and Methods Male rats were randomly divided into three groups (n=15 in each): the control group, the transperineal ligation group, and the transperitoneal ligation group. Four weeks after the ligation procedure, cystometrography was performed and oxidative stress, pro-inflammatory cytokine levels, and histologic changes were evaluated. Oxidative stress was assessed by measuring 8-hydroxy-20-deoxyguanosine and superoxide dismutase, and pro-inflammatory cytokine activity was investigated by measuring levels of interleukin (IL)-6, IL-8, and tumor necrosis factor-α. Results The transperineal model led to results similar to those observed for the transperitoneal model, namely (1) increased voiding frequency and reductions in the non-voiding contraction interval and the maximal vesical pressure, (2) increased levels of oxidative stress markers, (3) increased pro-inflammatory cytokine levels, and (4) fibrotic changes in the bladder tissue. Conclusions We suggest that the transperineal procedure can be used as an alternative OAB model in male rats. PMID:27574597

  6. 32-GHz Wideband Maser Amplifier

    NASA Technical Reports Server (NTRS)

    Shell, J. S.; Neff, D. E.

    1990-01-01

    High-gain, wideband, microwave amplifier based on ruby cooled by liquid helium. Features include low input equivalent noise temperature and 400-MHz bandwidth. Design basically extension of previous reflected-wave masers built for frequency range of 18 to 26 GHz. Maser amplifier includes eight stages connected in reflected-wave configuration. Particularly useful for detection of weak microwave signals in radio astronomy and communications.

  7. Dye laser traveling wave amplifier

    NASA Technical Reports Server (NTRS)

    Davidson, F.; Hohman, J.

    1984-01-01

    A flashlamp pumped dye laser suitable for use as a single stage amplifier is described. Particular emphasis is placed on the efforts to increase output pulse energy and improve the temporal profile of the injected pulse. By using high power thin film polarizers, output energies reach from 4 to 45 mJ. Various dispersive elements are used to develop an amplified pulse with an extremely clean temporal profile.

  8. 32-GHz Wideband Maser Amplifier

    NASA Technical Reports Server (NTRS)

    Shell, J. S.; Neff, D. E.

    1990-01-01

    High-gain, wideband, microwave amplifier based on ruby cooled by liquid helium. Features include low input equivalent noise temperature and 400-MHz bandwidth. Design basically extension of previous reflected-wave masers built for frequency range of 18 to 26 GHz. Maser amplifier includes eight stages connected in reflected-wave configuration. Particularly useful for detection of weak microwave signals in radio astronomy and communications.

  9. Operational amplifiers-some misconceptions

    NASA Astrophysics Data System (ADS)

    Summers, M. K.

    1980-03-01

    The simplified theoretical treatments of operational amplifier behaviour found in material for use by teachers and students is often misleading and sometimes inaccurate. The author identifies some of these inadequacies and describes some pedagogical pitfalls which are best avoided. The closed loop gain of an operational amplifier in the inverting configuration taken from the JMB publication Physics (Advanced)-Notes on the Core Syllabus (1978a) is reproduced to act as a focus for discussion.

  10. Butelase-mediated cyclization and ligation of peptides and proteins.

    PubMed

    Nguyen, Giang K T; Qiu, Yibo; Cao, Yuan; Hemu, Xinya; Liu, Chuan-Fa; Tam, James P

    2016-10-01

    Enzymes that catalyze efficient macrocyclization or site-specific ligation of peptides and proteins can enable tools for drug design and protein engineering. Here we describe a protocol to use butelase 1, a recently discovered peptide ligase, for high-efficiency cyclization and ligation of peptides and proteins ranging in size from 10 to >200 residues. Butelase 1 is the fastest known ligase and is found in pods of the common medicinal plant Clitoria ternatea (also known as butterfly pea). It has a very simple C-terminal-specific recognition motif that requires Asn/Asp (Asx) at the P1 position and a dipeptide His-Val at the P1' and P2' positions. Substrates for butelase-mediated ligation can be prepared by standard Fmoc (9-fluorenylmethyloxycarbonyl) chemistry or recombinant expression with the minimal addition of this tripeptide Asn-His-Val motif at the C terminus. Butelase 1 achieves cyclizations that are 20,000 times faster than those of sortase A, a commonly used enzyme for backbone cyclization. Unlike sortase A, butelase is traceless, and it can be used for the total synthesis of naturally occurring peptides and proteins. Furthermore, butelase 1 is also useful for intermolecular ligations and synthesis of peptide or protein thioesters, which are versatile activated intermediates necessary for and compatible with many chemical ligation methods. The protocol describes steps for isolation and purification of butelase 1 from plant extract using a four-step chromatography procedure, which takes ∼3 d. We then describe steps for intramolecular cyclization, intermolecular ligation and butelase-mediated synthesis of protein thioesters. Butelase reactions are generally completed within minutes and often achieve excellent yields.

  11. Results of rubber band ligation of esophageal varices.

    PubMed

    Leszczyszyn, J; Łebski, I; Massopust, R; Skoczylas, M; Janus, W

    2001-05-01

    The aim of the paper is to analyze the results of endoscopic rubber band ligation of esophageal varices performed between 1 January 1998 and 1 November 2000 at the Department of GI Surgery of 4th Military University Hospital. Cases of 50 patients with massive upper GI variceal bleeding present on admission or with the history of such a bleeding were reviewed. A total of 85 endoscopic procedures of rubber band ligation were performed. In 9 (18%) cases ligation was performed due to massive variceal bleeding, in 1 case the complementary obliteration of stomach fundus varices with Aethoxysclerol was performed. In 10 (20%) cases in grade C of Child-Pough scale of liver failure, 3 endoscopic procedures were performed, in 15 (30%) in grade B--2 procedures, in the remaining 25 (50%) cases, also in grade B--1 procedure was performed. Procedures were conducted with Wilson-Cook Multi-Band Ligator SAEED SixShooter. In all cases with non-bleeding esophageal varices the overall good result of treatment was achieved, with collapsing of variceal columns. In 8 (88.8%) of 9 cases treated due to variceal bleeding, good hemostasis was achieved and no reintervention was necessary. In 1 case of massive variceal bleeding endoscopic treatment failed and patient eventually died. In 25 (50%) cases the complementary (1 or 2) rubber band ligations were performed. Follow-up period has ranged from 1 to 34 months. No cases of severe complications after the procedure were noted. In early period after the procedure 43 (86%) patients complained of transient, mild retrosternal pain and mild to moderate dysphagia. Endoscopic rubber band ligation is a safe and effective treatment for esophageal varices both in cases of variceal bleeding and as elective procedure.

  12. Brachial artery aneurysms following brachio-cephalic AV fistula ligation.

    PubMed

    Khalid, Usman; Parkinson, Frances; Mohiuddin, Kamran; Davies, Paula; Woolgar, Justin

    2014-01-01

    Peripheral artery aneurysms proximal to a long-standing arteriovenous (AV) fistula can be a serious complication. It is important to be aware of this and manage it appropriately. Vascular access nurses input all data regarding patients undergoing dialysis access procedures into a securely held database prospectively. This was retrospectively reviewed to identify cases of brachial artery aneurysms over the last 3 years. In Morriston Hospital, around 200 forearm and arm AV fistulas are performed annually for vascular access in renal dialysis patients. Of these, approximately 15 (7.5%) are ligated. Three patients who had developed brachial artery aneurysms following AV fistula ligation were identified. All 3 patients had developed brachial artery aneurysms following ligation of a long-standing brachio-cephalic AV fistula. Two patients presented with pain and a pulsatile mass in the arm, and one presented with pins and needles and discoloration of fingertips. Two were managed with resection of the aneurysm and reconstruction with a reversed long saphenous vein interposition graft, the third simply required ligation of a feeding arterial branch. True aneurysm formation proximal to an AV fistula that has been ligated is a rare complication. There are several reasons for why these aneurysms develop in such patients, the most plausible one being the increase in blood flow and resistance following ligation of the AV fistula. Of note, all the patients in this study were on immunosuppressive therapy following successful renal transplantation. Vigilance by the vascular access team and nephrologists is paramount to identify those patients who may warrant further evaluation and investigation by the vascular surgeon.

  13. Tubal ligation, hysterectomy and ovarian cancer: A meta-analysis

    PubMed Central

    2012-01-01

    Purpose The purpose of this meta-analysis was to determine the strength of the association between gynecologic surgeries, tubal ligation and hysterectomy, and ovarian cancer. Methods We searched the PubMed, Web of Science, and Embase databases for all English-language articles dated between 1969 through March 2011 using the keywords “ovarian cancer” and “tubal ligation” or “tubal sterilization” or “hysterectomy.” We identified 30 studies on tubal ligation and 24 studies on hysterectomy that provided relative risks for ovarian cancer and a p-value or 95% confidence interval (CI) to include in the meta-analysis. Summary RRs and 95% CIs were calculated using a random-effects model. Results The summary RR for women with vs. without tubal ligation was 0.70 (95%CI: 0.64, 0.75). Similarly, the summary RR for women with vs. without hysterectomy was 0.74 (95%CI: 0.65, 0.84). Simple hysterectomy and hysterectomy with unilateral oophorectomy were associated with a similar decrease in risk (summery RR = 0.62, 95%CI: 0.49-0.79 and 0.60, 95%CI: 0.47-0.78, respectively). In secondary analyses, the association between tubal ligation and ovarian cancer risk was stronger for endometrioid tumors (summary RR = 0.45, 95%CI: 0.33, 0.61) compared to serous tumors. Conclusion Observational epidemiologic evidence strongly supports that tubal ligation and hysterectomy are associated with a decrease in the risk of ovarian cancer, by approximately 26-30%. Additional research is needed to determine whether the association between tubal ligation and hysterectomy on ovarian cancer risk differs by individual, surgical, and tumor characteristics. PMID:22587442

  14. Treatment of spontaneous tumours by temporary local ligation

    PubMed Central

    Allen, Frederick M.; Kaplan, Martin M.; Meranze, David R.; Gradess, Morton

    1960-01-01

    Previous work in some human cases and in laboratory animals has indicated that temporary local ligation of spontaneous tumours has a selective destructive effect on these tumours, with only temporary inflammation resulting in normal tissues. In the experiments described in this paper, 49 spontaneous accessible tumours in dogs were treated by this method, with periods of ligation of from 4 to 11 hours. Success, as measured by selective necrosis of tumour tissue as compared with normal tissue, was achieved in 29 out of 41 benign tumours, including lipomas, angiomas, adenomas and mixed mammary tumours. Treatment failures were encountered in two cases each of papillomas and fibromas, six mixed mammary tumours and two testicular tumours. Total necrosis of tumour cells occurred in all eight malignant tumours encountered in this series. The outstanding feature was the specific destruction of tumour tissue by a bodily process without participation of any outside agent. Emphasis was placed on an adequate inflammatory response following temporary anoxia, although a precise definition of this inflammation could not be offered. Post-ligation bacterial multiplication, which may be expected to occur in necrotic tumour tissue, is considered to be a secondary effect rather than a possible primary cause of regression and disappearance of the tumour. If ligation treatment can be shown to be successful for a particular type of tumour, it may be possible to apply it to human patients for the treatment of areas not amenable to surgery. The results reported here warrant new experimental approaches to the study of neoplasms at the cellular level to define more precisely the anoxic and inflammatory processes involved in the selective lethal effect on tumour tissues; and the authors suggest that trials should be undertaken of combinations of chemotherapy or irradiation with ligation to reduce ligation time and extend the possible benefits. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5FIG. 6FIG. 7

  15. Endocrine profile of patients with post-tubal-ligation syndrome.

    PubMed

    Hargrove, J T; Abraham, G E

    1981-07-01

    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.

  16. Sequelae of tubal ligation: an analysis of 75 consecutive hysterectomies.

    PubMed

    Stock, R J

    1984-10-01

    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.

  17. RNA self-ligation: from oligonucleotides to full length ribozymes.

    PubMed

    Gwiazda, Slawomir; Salomon, Kristina; Appel, Bettina; Müller, Sabine

    2012-07-01

    The RNA-world-theory is one possible explanation of how life on earth has evolved. In this context it is of high interest to search for molecular systems, capable of self-organization into structures with increasing complexity. We have engineered a simple catalytic system in which two short RNA molecules can catalyze their own ligation to form a larger RNA construct. The system is based on the hairpin ribozyme using a 2',3'-cyclophosphate as activated species for ligation. 2',3'-cyclic phosphates can be easily formed and occur in many natural systems, thus being superior candidates for activated building blocks in RNA world scenarios.

  18. Alternative Okazaki Fragment Ligation Pathway by DNA Ligase III.

    PubMed

    Arakawa, Hiroshi; Iliakis, George

    2015-06-23

    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

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

    PubMed

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

    2012-01-01

    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.

  20. The Microstrip DC SQUID Amplifier

    NASA Astrophysics Data System (ADS)

    Mück, Michael

    2000-03-01

    We have developed an extremely sensitive rf amplifier based on the dc superconducting quantum interference device (dc SQUID). Unlike a conventional semiconductor amplifier, a SQUID can be cooled to ultra low temperatures (300 mK or less) and thus potentially achieve a much lower noise temperature. In a conventional SQUID amplifier, where the integrated input coil is operated as a lumped element, parasitic capacitance between the coil and the SQUID washer limits the frequency up to which a substantial gain can be achieved to a few hundred MHz. This problem can be circumvented by operating the input coil of the SQUID as a microstrip resonator: instead of connecting the input signal between the two ends of the coil, it is connected between the SQUID washer and one end of the coil; the other end is left open. Such amplifiers have gains of 20 dB or more at frequencies up to 1.5 GHz. The resonant nature of the input circuit limits the -3 dB bandwidth of the amplifier to at most 100 MHz. The resonant frequency of the microstrip can be tuned, however, by means of a varactor diode connected across the otherwise open end of the resonator. The noise temperature of microstrip SQUID amplifiers was measured to be between 0.5 K ± 0.3 K at a resonant frequency of 80 MHz and 1.6 K ± 1.2 K at 1 GHz. An even lower noise temperature can be achieved by cooling the SQUID to about 0.4 K. In this case, a noise temperature of 100 mK ± 20 mK was achieved at 90 MHz, and of about 120 ± 100 mK at 440 MHz. The gain of the SQUID amplifier is sensitive to changes of the static magnetic flux through the SQUID. In order to prevent low frequency magnetic noise from changing the amplifier gain, we developed a directly coupled flux-locked loop which stabilizes the static flux bias of the SQUID. Finally, although the maximum output voltage of the SQUID amplifier is relatively small, two-tone intermodulation measurements show an intermodulation-free dynamic range of nearly 50 dB in a bandwidth of

  1. Magnetic Ligation Method for Quantitative Detection of MicroRNAs

    PubMed Central

    Liong, Monty; Im, Hyungsoon; Majmudar, Maulik D.; Aguirre, Aaron D.; Sebas, Matthew; Lee, Hakho; Weissleder, Ralph

    2014-01-01

    A magnetic ligation method is utilized for the detection of microRNAs amongst a complex biological background without polymerase chain reaction or nucleotide modification. The sandwich probes assay can be adapted to analyze a panel of microRNAs associated with cardiovascular diseases in heart tissue samples. PMID:24532323

  2. Thoracoscopic Pericardial Window Creation and Thoracic Duct Ligation in Neonates

    PubMed Central

    Ouzounian, Steven P.; Napoleon, Lori; Permut, Lester C.; Golombek, Sergio G.

    2003-01-01

    Objective: We describe 2 newborn infants with persistent pericardial effusion treated with thoracoscopic pericardial window and thoracic duct ligation. Methods: Patient 1 was a premature female newborn who presented with severe cardiac anomalies, including dextrocardia. She was treated with pulmonary artery banding and pacemaker placement for complete cardiac block. Postoperatively, she developed pericarditis with persistent symptomatic pericardial effusion. She did not improve despite pericardial drain placement. She was treated with a thoracoscopic pericardial window. Patient 2 was a newborn male who presented with cardiac tamponade secondary to congenital chylopericardium. He did not respond to pericardial drain placement or medical management with fasting, total parenteral nutrition, and octreotide. He was treated with thoracoscopic pericardial window and thoracic duct ligation. Results: Patient 1 improved rapidly. The pericardial effusion disappeared. The chest tube was removed 5 days following surgery. She died 6 weeks later of a cardiac arrhythmia secondary to pacemaker failure. The pericardial effusion had resolved. Patient 2 responded to the pericardial window and thoracic duct ligation. He was discharged 10 days following the procedure. Conclusions: Thoracoscopy provides an excellent approach to the pericardium. Pericardial windows and biopsy can be safely performed with this approach. The thoracic duct can be easily identified and ligated even in small babies. Recovery can be fast with minimal postoperative discomfort. Cosmetic results are excellent and length of hospitalization is minimized. PMID:14626403

  3. A Simple Suturing Technique for Laparoscopic Ligation of Vascular Pedicles

    PubMed Central

    Aqua, Keith A.

    1996-01-01

    We report on the performance of 348 adnexectomies and 35 uterine artery ligations for both benign and malignant disease using a simple laparoscopic suturing technique. Only 5-mm ports are required, and there was no morbidity directly associated with this approach. The procedure can be performed quickly, is relatively inexpensive, and allows hysterectomy and oophorectomy to be performed without bipolar electrocautery. PMID:18493392

  4. Protein chemical synthesis by α-ketoacid-hydroxylamine ligation.

    PubMed

    Harmand, Thibault J; Murar, Claudia E; Bode, Jeffrey W

    2016-06-01

    Total chemical synthesis of proteins allows researchers to custom design proteins without the complex molecular biology that is required to insert non-natural amino acids or the biocontamination that arises from methods relying on overexpression in cells. We describe a detailed procedure for the chemical synthesis of proteins with the α-ketoacid-hydroxylamine (KAHA ligation), using (S)-5-oxaproline (Opr) as a key building block. This protocol comprises two main parts: (i) the synthesis of peptide fragments by standard fluorenylmethoxycarbonyl (Fmoc) chemistry and (ii) the KAHA ligation between fragments containing Opr and a C-terminal peptide α-ketoacid. This procedure provides an alternative to native chemical ligation (NCL) that could be valuable for the synthesis of proteins, particularly targets that do not contain cysteine residues. The ligation conditions-acidic DMSO/H2O or N-methyl-2-pyrrolidinone (NMP)/H2O-are ideally suited for solubilizing peptide segments, including many hydrophobic examples. The utility and efficiency of the protocol is demonstrated by the total chemical synthesis of the mature betatrophin (also called ANGPTL8), a 177-residue protein that contains no cysteine residues. With this protocol, the total synthesis of the betatrophin protein has been achieved in around 35 working days on a multimilligram scale.

  5. Optimization of ligation reaction conditions in gene synthesis.

    PubMed

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

    1988-05-01

    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.

  6. Reflex ring laser amplifier system

    DOEpatents

    Summers, M.A.

    1983-08-31

    The invention is a method and apparatus for providing a reflex ring laser system for amplifying an input laser pulse. The invention is particularly useful in laser fusion experiments where efficient production of high-energy and high power laser pulses is required. The invention comprises a large aperture laser amplifier in an unstable ring resonator which includes a combination spatial filter and beam expander having a magnification greater than unity. An input pulse is injected into the resonator, e.g., through an aperture in an input mirror. The injected pulse passes through the amplifier and spatial filter/expander components on each pass around the ring. The unstable resonator is designed to permit only a predetermined number of passes before the amplified pulse exits the resonator. On the first pass through the amplifier, the beam fills only a small central region of the gain medium. On each successive pass, the beam has been expanded to fill the next concentric non-overlapping region of the gain medium.

  7. Sequence fidelity of a template-directed PNA-ligation reaction.

    PubMed

    Mattes, A; Seitz, O

    2001-10-21

    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.

  8. Click nucleic acid ligation: applications in biology and nanotechnology.

    PubMed

    El-Sagheer, Afaf H; Brown, Tom

    2012-08-21

    Biochemical strategies that use a combination of synthetic oligonucleotides, thermostable DNA polymerases, and DNA ligases can produce large DNA constructs up to 1 megabase in length. Although these ambitious targets are feasible biochemically, comparable technologies for the chemical synthesis of long DNA strands lag far behind. The best available chemical approach is the solid-phase phosphoramidite method, which can be used to assemble DNA strands up to 150 bases in length. Beyond this point, deficiencies in the chemistry make it impossible to produce pure DNA. A possible alternative approach to the chemical synthesis of large DNA strands is to join together carefully purified synthetic oligonucleotides by chemical methods. Click ligation by the copper-catalyzed azide-alkyne (CuAAC) reaction could facilitate this process. In this Account, we describe the synthesis, characterization, and applications of oligonucleotides prepared by click ligation. The alkyne and azide oligonucleotide strands can be prepared by standard protocols, and the ligation reaction is compatible with a wide range of chemical modifications to DNA and RNA. We have employed click ligation to synthesize DNA constructs up to 300 bases in length and much longer sequences are feasible. When the resulting triazole linkage is placed in a PCR template, various DNA polymerases correctly copy the entire base sequence. We have also successfully demonstrated both in vitro transcription and rolling circle amplification through the modified linkage. This linkage has shown in vivo biocompatibility: an antibiotic resistance gene containing triazole linkages functions in E. coli . Using click ligation, we have synthesized hairpin ribozymes up to 100 nucleotides in length and a hammerhead ribozyme with the triazole linkage located at the substrate cleavage site. At the opposite end of the length scale, click-ligated, cyclic mini-DNA duplexes have been used as models to study base pairing. Cyclic duplexes have

  9. Limit circuit prevents overdriving of operational amplifier

    NASA Technical Reports Server (NTRS)

    Openshaw, F. L.

    1967-01-01

    Cutoff-type high gain amplifier coupled by a diode prevents overdriving of operational amplifier. An amplified feedback signal offsets the excess input signal that tends to cause the amplifier to exceed its preset limit. The output is, therfore, held to the set clamp level.

  10. The effect of tubal ligation on the incidence of epithelial cancer of the ovary.

    PubMed

    Koch, M; Starreveld, A A; Hill, G B; Jenkins, H

    1984-01-01

    A retrospective review of 666 women who underwent tubal ligation between 1930 and 1969 in Alberta, Canada, was undertaken to assess the effect of tubal ligation on the incidence of ovarian cancer. Tubal ligation did not affect the risk of ulterior ovarian cancer except in women who underwent tubal ligation between the ages of 20 and 29. These women showed a slight but statistically significant (p = 0.03) increase in observed versus expected cases of ovarian cancer.

  11. Tubal ligation and ovarian cancer risk in African American women.

    PubMed

    McNamara, Chrissy; Abbott, Sarah E; Bandera, Elisa V; Qin, Bo; Peres, Lauren C; Camacho, Fabian; Moorman, Patricia G; Alberg, Anthony J; Barnholtz-Sloan, Jill S; Bondy, Melissa; Cote, Michele L; Funkhouser, Ellen; Peters, Edward S; Schwartz, Ann G; Schildkraut, Joellen M; Terry, Paul

    2017-09-04

    Tubal ligation has been associated with reduced risk of epithelial ovarian cancer (EOC) in studies of primarily white women, but less is known about the association in African American (AA) women. We sought to evaluate the associations among 597 invasive ovarian cancer cases and 742 controls of AA descent recruited from the African American Cancer Epidemiology Study, a population-based case-control study in 11 geographical areas in the US. Multivariable logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusted for potentially confounding factors. An inverse association between tubal ligation and EOC was observed that was not statistically significant (OR 0.88, 95% CI 0.68-1.14). However, an inverse association with EOC risk was observed among women who had a tubal ligation at age 35 years or older (OR 0.64; 95% CI 0.41-0.98), but not among those who had a tubal ligation before age 35 (OR 0.98; 95% CI 0.74-1.29) (p for interaction = 0.08). The association also varied considerably by tumor subtype. A strong inverse association was observed for endometrioid tumors (OR 0.31, 95% CI 0.14-0.70), whereas associations with mucinous (OR 0.87, 95% CI 0.36-2.12) and serous (OR 0.94, 95% CI 0.71-1.24) tumors were weaker and not statistically significant. A statistically non-significant positive association for clear cell tumors (OR 1.84, 95% CI 0.58-5.82) was based on a low number of cases. Our findings show that tubal ligation may confer a reduced risk for EOC among AA women that is comparable to the associations that have been previously observed in primarily white populations.

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

    PubMed Central

    Maia, Lúcio Henrique Esmeraldo Gurgel; Lopes Filho, Hibernon; Ruellas, Antônio Carlos de Oliveira; Araújo, Mônica Tirre de Souza; Vaitsman, Delmo Santiago

    2014-01-01

    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. PMID:24945521

  13. Frictional forces related to self-ligating brackets.

    PubMed

    Pizzoni, L; Ravnholt, G; Melsen, B

    1998-06-01

    Orthodontic tooth movement can be regarded as teeth sliding on a wire like pearls on a string, the force being supplied by springs or elastics. The movement implies friction between wire and bracket, taking up part of the force and leaving an uncontrolled amount to act on the teeth. The friction is likely to depend on bracket construction and wire material. Therefore, in this investigation the friction of self-ligating brackets and beta-titanium wires was evaluated, as opposed to more conventional configurations. Carried by low-friction linear ball bearings, a bracket was made to slide along an out-stretched archwire with minimal (and known) basic friction, either parallel or at an angle to the wire. Two self-ligating brackets were used in their closed position without any normal force. Friction was tested against four wires: stainless steel and beta-titanium, both in round and rectangular cross-sections. The force used to overcome friction and to move the bracket was measured on a testing machine at 10 mm/min, and the basic friction was subtracted. The results show that round wires had a lower friction than rectangular wires, the beta-titanium wires had a markedly higher friction than stainless steel wires, and friction increased with angulation for all bracket/wire combinations. The self-ligating brackets had a markedly lower friction than conventional brackets at all angulations, and self-ligating brackets, closed by the capping of a conventional design, exhibited a significantly lower friction than self-ligating brackets closed by a spring. The selection of bracket design, wire material, and wire cross-section significantly influences the forces acting in a continuous arch system.

  14. Application of an omonasteine ligation strategy for the total chemical synthesis of the BRD7 bromodomain.

    PubMed

    Van de Vijver, Pieter; Scheer, Liesbeth; van Beijnum, Judy; Griffioen, Arjan; Hackeng, Tilman M

    2012-09-28

    The use of omonasteine (Omo) in sequential peptide ligation strategies extends the scope of homocysteine (Hcy) ligation to longer, methionine-rich proteins. Hcy-to-Omo conversion can be performed on-resin, while the Omo-to-Hcy deprotection can be performed in situ after peptide ligation. This strategy was successfully applied in the synthesis of the BRD7 bromodomain.

  15. Laser system using regenerative amplifier

    DOEpatents

    Emmett, John L. [Pleasanton, CA

    1980-03-04

    High energy laser system using a regenerative amplifier, which relaxes all constraints on laser components other than the intrinsic damage level of matter, so as to enable use of available laser system components. This can be accomplished by use of segmented components, spatial filters, at least one amplifier using solid state or gaseous media, and separated reflector members providing a long round trip time through the regenerative cavity, thereby allowing slower switching and adequate time to clear the spatial filters, etc. The laser system simplifies component requirements and reduces component cost while providing high energy output.

  16. Optical amplifiers for coherent lidar

    NASA Technical Reports Server (NTRS)

    Fork, Richard

    1996-01-01

    We examine application of optical amplification to coherent lidar for the case of a weak return signal (a number of quanta of the return optical field close to unity). We consider the option that has been explored to date, namely, incorporation of an optical amplifier operated in a linear manner located after reception of the signal and immediately prior to heterodyning and photodetection. We also consider alternative strategies where the coherent interaction, the nonlinear processes, and the amplification are not necessarily constrained to occur in the manner investigated to date. We include the complications that occur because of mechanisms that occur at the level of a few, or one, quantum excitation. Two factors combine in the work to date that limit the value of the approach. These are: (1) the weak signal tends to require operation of the amplifier in the linear regime where the important advantages of nonlinear optical processing are not accessed, (2) the linear optical amplifier has a -3dB noise figure (SN(out)/SN(in)) that necessarily degrades the signal. Some improvement is gained because the gain provided by the optical amplifier can be used to overcome losses in the heterodyned process and photodetection. The result, however, is that introduction of an optical amplifier in a well optimized coherent lidar system results in, at best, a modest improvement in signal to noise. Some improvement may also be realized on incorporating more optical components in a coherent lidar system for purely practical reasons. For example, more compact, lighter weight, components, more robust alignment, or more rapid processing may be gained. We further find that there remain a number of potentially valuable, but unexplored options offered both by the rapidly expanding base of optical technology and the recent investigation of novel nonlinear coherent interference phenomena occurring at the single quantum excitation level. Key findings are: (1) insertion of linear optical

  17. Design considerations for neural amplifiers.

    PubMed

    Holleman, Jeremy

    2016-08-01

    The initial amplification stage is a critical element of a neural signal acquisition system, and the design of low-noise, low-power amplifiers has received a great deal of attention in recent publications. In this paper we discuss practical considerations for the design of amplifiers intended for neural interfaces. Noise is a major issue due to the low amplitude of neural signals. Practical system deployments also require adequate rejection of common-mode interference, such as that due to line power noise or muscle artifacts, and supply noise. This paper attempts to provide some guideance for system and circuit designers and point out opportunities for potential future exploration.

  18. Coherent amplified optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Rao, Bin; Chen, Zhongping

    2007-07-01

    A technique to improve the signal-to-noise ratio (SNR) of a high speed 1300 nm swept source optical coherence tomography (SSOCT) system was demonstrated. A semiconductor optical amplifier (SOA) was employed in the sample arm to coherently amplify the weak light back-scattered from sample tissue without increasing laser power illuminated on the sample. The image quality improvement was visualized and quantified by imaging the anterior segment of a rabbit eye at imaging speed of 20,000 A-lines per second. The theory analysis of SNR gain is given followed by the discussion on the technologies that can further improve the SNR gain.

  19. Reactanceless synthesized impedance bandpass amplifier

    NASA Technical Reports Server (NTRS)

    Kleinberg, L. L. (Inventor)

    1985-01-01

    An active R bandpass filter network is formed by four operational amplifier stages interconnected by discrete resistances. One pair of stages synthesize an equivalent input impedance of an inductance (L sub eq) in parallel with a discrete resistance (R sub o) while the second pair of stages synthesizes an equivalent input impedance of a capacitance (C sub eq) serially coupled to another discrete resistance (R sub i) coupled in parallel with the first two stages. The equivalent input impedances aggregately define a tuned resonant bandpass filter in the roll-off regions of the operational amplifiers.

  20. Laser system using regenerative amplifier

    DOEpatents

    Emmett, J.L.

    1980-03-04

    High energy laser system is disclosed using a regenerative amplifier, which relaxes all constraints on laser components other than the intrinsic damage level of matter, so as to enable use of available laser system components. This can be accomplished by use of segmented components, spatial filters, at least one amplifier using solid state or gaseous media, and separated reflector members providing a long round trip time through the regenerative cavity, thereby allowing slower switching and adequate time to clear the spatial filters, etc. The laser system simplifies component requirements and reduces component cost while providing high energy output. 10 figs.

  1. Balloon-augmented Onyx endovascular ligation: initial human experience and comparison with coil ligation.

    PubMed

    Osanai, Toshiya; Bain, Mark D; Toth, Gabor; Hussain, M Shazam; Hui, Ferdinand K

    2015-08-01

    Carotid artery sacrifice remains an important procedure for cerebral vascular disorders despite the development of new endovascular devices. Conventional carotid artery sacrifice with detachable coils alone often requires numerous coils to complete occlusion. To describe the initial human experience with balloon-augmented Onyx and coil vessel sacrifice based on our previous experience with animals. We performed a retrospective review of patients who underwent carotid artery sacrifice between 2008 and 2012 in accordance with local investigational review board approval. Two methods were used to occlude carotid arteries-namely, combined Onyx and coil embolization and traditional coil embolization. We compared the two methods for the cost of embolizate, time to occlude the vessels, and the number of coils. Eight consecutive patients (combined group n=3, traditional group n=5) were assessed. The median cost of embolic material was $6321 in the combined Onyx and coil embolization group and $29 996 in the traditional coil embolization group. The median time from first coil placement to achievement of vessel occlusion was 52 min in the Onyx group and 113 min in the coil embolization group. The median number of coils used was 4 in the Onyx group and 35 in the coil embolization group (p<0.05). No symptomatic complications or recurrences were seen in the combined group. Balloon-augmented Onyx endovascular ligation may reduce costs and fluoroscopy times during vessel sacrifice. Further studies in a larger number of patients are needed to confirm these findings. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  2. MALS: an efficient strategy for multiple site-directed mutagenesis employing a combination of DNA amplification, ligation and suppression PCR

    PubMed Central

    Fushan, Alexey A; Drayna, Dennis T

    2009-01-01

    Background Multiple approaches for the site-directed mutagenesis (SDM) have been developed. However, only several of them are designed for simultaneous introduction of multiple nucleotide alterations, and these are time consuming. In addition, many of the existing multiple SDM methods have technical limitations associated with type and number of mutations that can be introduced, or are technically demanding and require special chemical reagents. Results In this study we developed a quick and efficient strategy for introduction of multiple complex mutations in a target DNA without intermediate subcloning by using a combination of connecting SDM and suppression PCR. The procedure consists of sequential rounds, with each individual round including PCR amplification of target DNA with two non-overlapping pairs of oligonucleotides. The desired mutation is incorporated at the 5' end of one or both internal oligonucleotides. DNA fragments obtained during amplification are mixed and ligated. The resulting DNA mixture is amplified with external oligonucleotides that act as suppression adapters. Suppression PCR limits amplification to DNA molecules representing full length target DNA, while amplification of other types of molecules formed during ligation is suppressed. To create additional mutations, an aliquot of the ligation mixture is then used directly for the next round of mutagenesis employing internal oligonucleotides specific for another region of target DNA. Conclusion A wide variety of complex multiple mutations can be generated in a short period of time. The procedure is rapid, highly efficient and does not require special chemical reagents. Thus, MALS represents a powerful alternative to the existing methods for multiple SDM. PMID:19778447

  3. Treatment efficiency of conventional vs self-ligating brackets: effects of archwire size and material.

    PubMed

    Turnbull, Nicholas R; Birnie, David J

    2007-03-01

    In this prospective clinical study, we assessed the relative speed of archwire changes, comparing self-ligating brackets with conventional elastomeric ligation methods, and further assessed this in relation to the stage of orthodontic treatment represented by different wire sizes and types. The time taken to remove and ligate archwires for 131 consecutive patients treated with either self-ligating or conventional brackets was prospectively assessed. The study was carried out in the orthodontic department of a district general hospital in the United Kingdom. The main outcome measure was the time to remove or place elastomeric ligatures or open/close self-ligating brackets for 2 matched groups of fixed appliance patients: Damon2 self-ligating bracket (SDS Ormco, Orange, Calif) and a conventional mini-twin bracket (Orthos, SDS Ormco). The relative effects of various wire sizes and materials on ligation times were investigated. The study was carried out by 1 operator experienced in the use of self-ligating and conventional brackets. The Damon2 self-ligating system had a significantly shorter mean archwire ligation time for both placing (P <.001) and removing (P <.01) wires compared with the conventional elastomeric system. Ligation of an archwire was approximately twice as quick with the self-ligating system. Opening a Damon slide was on average 1 second quicker per bracket than removing an elastic from the mini-twin brackets, and closing a slide was 2 seconds faster per bracket. This difference in ligation time between the Damon2 and the conventional mini-twin brackets became more marked for larger wire sizes used in later treatment stages. The type of bracket and the size of wire used are statistically significant predictors for speed of ligation and chairside time. The self-ligating system offered quicker and arguably more efficient wire removal and placement for most orthodontic treatment stages.

  4. Dye laser traveling wave amplifier

    NASA Technical Reports Server (NTRS)

    Davidson, F.

    1983-01-01

    A flash lamp pumped dye laser suitable for use as an amplifier stage was developed. The desired output laser pulses are of nanosecond duration, tunable in center frequency, and of good optical quality. Its usefulness as a laser oscillator is emphasized, because it constitutes a compact, relatively efficient source of tunable dye laser light.

  5. Hybrid EDFA/Raman Amplifiers

    NASA Astrophysics Data System (ADS)

    Masuda, Hiroji

    This chapter describes the technologies needed for cascading an erbium-doped fiber amplifier (EDFA) and a fiber Raman amplifier (FRA or RA) to create a hybrid amplifier (HA), the EDFA/Raman HA. Two kinds of HA are defined in this chapter: the narrowband HA (NB-HA) and the seamless and wideband HA (SWB-HA). The NB-HA employs distributed Raman amplification in the transmission fiber together with an EDFA and provides low noise transmission in the C- or L-band. The noise figure of the transmission line is lower than it would be if only an EDFA were used. The SWB-HA, on the other hand, employs distributed or discrete Raman amplification together with an EDFA, and provides a low-noise and wideband transmission line or a low-noise and wideband discrete amplifier for the C- and L-bands. The typical gain bandwidth (Δλ) of the NB-HA is ~30 to 40 nm, whereas that of the SWB-HA is ~70 to 80 nm.

  6. Recent extensions to native chemical ligation for the chemical synthesis of peptides and proteins.

    PubMed

    Malins, Lara R; Payne, Richard J

    2014-10-01

    Native chemical ligation continues to play a pivotal role in the synthesis of increasingly complex peptide and protein targets twenty years after its initial report. This opinion article will highlight a number of recent, powerful extensions of the technology that have expanded the scope of the reaction, accelerated ligation rates, enabled chemoselective post-ligation modifications, and streamlined the ligation of multiple peptide fragments. These advances have facilitated the synthesis of a number of impressive protein targets to date and hold great promise for the continued application of native chemical ligation for the detailed study of protein structure and function. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Ligation-free ribosome profiling of cell type-specific translation in the brain.

    PubMed

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

    2016-07-05

    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.

  8. Addition of HOBt improves the conversion of thioester-Amine chemical ligation.

    PubMed

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

    2015-11-01

    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.

  9. Ligation-mediated PCR amplification of specific fragments from a class-II restriction endonuclease total digest.

    PubMed Central

    Guilfoyle, R A; Leeck, C L; Kroening, K D; Smith, L M; Guo, Z

    1997-01-01

    A method is described which permits the ligation- mediated PCR amplification of specific fragments from a Class-II restriction endonuclease total digest. Feasibility was tested using Bcl I and phage lambda DNA as a model enzyme and amplicon system, respectively. Bcl I is one of many widely used restriction enzymes which cleave at palindromic recognition sequences and leave 5'-protruding ends of defined sequence. Using a single pair of universal primers, a given fragment can be specifically amplified after joining the fragments to adaptors consisting of a duplex primer region and a 9-nucleotide protruding single-stranded 5'-end containing the sequence complementary to the cleaved restriction site and a 4-nucleotide 'indexing sequence.' The protruding strand anneals to a restriction fragment by displacing its corresponding strand in the same fragment-specific indexing sequence located juxtaposed to the restriction site. The adaptor is covalently linked to the restriction fragment by T4 DNA ligase, and amplification is carried out under conditions for long-distance PCR using the M13 forward and reverse primers. The technique discriminated robustly between mismatches and perfect matches for the 16 indexing sequences tested to allow individual lambda Bcl I fragments to be amplified from their respective adaptor pairs. A strategy is proposed enabling a non-cloning approach to the accession, physical mapping and sequencing of genomic DNA. The method could also have application in high-throughput genetic mapping and fingerprinting and should expand the enzyme base for ligation- mediated indexing technology which has previously been limited to the Class-IIS and IP restriction endonucleases. PMID:9108171

  10. Internal iliac artery ligation for severe postpartum hemorrhage and severe hemorrhage after postpartum hysterectomy.

    PubMed

    Camuzcuoglu, Hakan; Toy, Harun; Vural, Mehmet; Yildiz, Fahrettin; Aydin, Halef

    2010-06-01

    The aim of this study was to evaluate the effect of internal iliac artery (IIA) ligation performed for severe postpartum hemorrhage (PPH). Thirty-three women who underwent IIA ligation to control PPH in a tertiary referral center between June 2007 and May 2009 were included in this retrospective analysis. IIA ligation was performed as the primary surgical intervention or to control bleeding following hysterectomy. The 33 women underwent IIA ligation due to uterine atony (n = 22), placenta previa accreta/increta/percreta (n = 5), uterine rupture (n = 4), and placental abruption (n = 2). Twenty-four women underwent IIA ligation as the primary surgical intervention. IIA ligation resulted in control of bleeding in 18/24 women (75%), and only 6/24 women (25%) showed unsuccessful management of bleeding with IIA ligation. In the six women for whom the bleeding was not controlled with IIA ligation, hysterectomy was urgently performed before closure of the abdomen. After obtaining adequate hemostasis with IIA ligation, no women required relaparotomy in the postoperative period. Nine women with persistent bleeding following hysterectomy were also treated with IIA ligation. In our study, there were no intraoperative or postoperative complications related to the procedure. IIA ligation may be an effective and safe treatment option to arrest severe PPH. This procedure may also be useful to arrest persistent hemorrhage after hysterectomy. Increased understanding of the retroperitoneal anatomy is needed to reduce the risk of intraoperative and postoperative serious complications.

  11. Acute salivary gland hypofunction in the duct ligation model in the absence of inflammation

    PubMed Central

    Correia, PN; Carpenter, GH; Osailan, SM; Paterson, KL; Proctor, GB

    2008-01-01

    Objective The commonly associated aetiology of salivary gland inflammation and salivary hypofunction has led to the widely held belief that inflammation causes salivary gland hypofunction. Indeed, our own recent study seemed to support this contention. Here, we tested the hypothesis that, in an acute duct ligation model, eliminating inflammation the submandibular gland would recover normal function. Materials and methods Ligation of the rat submandibular gland excretory duct for 24 h was used to induce inflammation and salivary gland hypofunction. A group of duct ligated rats was compared with a second group given dexamethasone, on the day of duct ligation. Twenty-four hours later salivary gland function was assessed and salivary glands were collected. Results Histology and myeloperoxidase activity assay revealed a profound decrease in inflammatory cell infiltration of ligated glands from rats given dexamethasone, compared with ligated glands in the absence of dexamethasone. Salivary flow rate evoked by methacholine was decreased (P < 0.01) by approximately 56% (ligated vs control, 79 ± 9 μl min−1 g−1vs 177 ± 11 μl min−1 g−1) and salivary flow from ligated dexamethasone-treated and ligated glands was similar. Conclusion Despite eliminating the inflammatory reaction in the ligated gland, salivary hypofunction was not reversed, suggesting that other mechanisms must be at work in the ligation-induced salivary hypofunction. PMID:18221457

  12. Critical evaluation and rate constants of chemoselective ligation reactions for stoichiometric conjugations in water.

    PubMed

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

    2015-04-17

    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.

  13. The Fidelity of Template-Directed Oligonucleotide Ligation and the Inevitability of Polymerase Function

    NASA Astrophysics Data System (ADS)

    James, Kenneth D.; Ellington, Andrew D.

    1999-08-01

    The first living systems may have employed template-directed oligonucleotide ligation for replication. The utility of oligonucleotide ligation as a mechanism for the origin and evolution of life is in part dependent on its fidelity. We have devised a method for evaluating ligation fidelity in which ligation substrates are selected from random sequence libraries. The fidelities of chemical and enzymatic ligation are compared under a variety of conditions. While reaction conditions can be found that promote high fidelity copying, departure from these conditions leads to error-prone copying. In particular, ligation reactions with shorter oligonucleotide substrates are less efficient but more faithful. These results support a model for origins in which there was selective pressure for template-directed oligonucleotide ligation to be gradually supplanted by mononucleotide polymerization.

  14. Endoscopic band ligation: Beyond prevention and management of gastroesophageal varices

    PubMed Central

    Ji, Jeong-Seon; Cho, Young-Seok

    2013-01-01

    Endoscopic band ligation (EBL) is the preferred endoscopic technique for the endoscopic treatment of acute esophageal variceal bleeding. EBL has also been used to treat nonvariceal bleeding. Recently, Han et al demonstrated that EBL can be a feasible and safe alternate technique for the management of iatrogenic gastric perforation especially in cases in which closure with endoclips is difficult. EBL is technically simpler to perform than other methods and provides a good view of the lesions under direct pressure and suction from the transparent ligation cap. EBL can be used even if the diameter of the perforation is greater than 10 mm or if there is a severe tangential angle. In this commentary, we discuss the efficacy and safety of EBL for the closure of iatrogenic gastrointestinal perforation. We also discuss the advantages and disadvantages of EBL for the treatment of nonvariceal bleeding. PMID:23885137

  15. Endoscopic band ligation: beyond prevention and management of gastroesophageal varices.

    PubMed

    Ji, Jeong-Seon; Cho, Young-Seok

    2013-07-21

    Endoscopic band ligation (EBL) is the preferred endoscopic technique for the endoscopic treatment of acute esophageal variceal bleeding. EBL has also been used to treat nonvariceal bleeding. Recently, Han et al demonstrated that EBL can be a feasible and safe alternate technique for the management of iatrogenic gastric perforation especially in cases in which closure with endoclips is difficult. EBL is technically simpler to perform than other methods and provides a good view of the lesions under direct pressure and suction from the transparent ligation cap. EBL can be used even if the diameter of the perforation is greater than 10 mm or if there is a severe tangential angle. In this commentary, we discuss the efficacy and safety of EBL for the closure of iatrogenic gastrointestinal perforation. We also discuss the advantages and disadvantages of EBL for the treatment of nonvariceal bleeding.

  16. Alkene-tetrazine ligation for imaging cellular DNA.

    PubMed

    Rieder, Ulrike; Luedtke, Nathan W

    2014-08-25

    5-Vinyl-2'-deoxyuridine (VdU) is the first reported metabolic probe for cellular DNA synthesis that can be visualized by using an inverse electron demand Diels-Alder reaction with a fluorescent tetrazine. VdU is incorporated by endogenous enzymes into the genomes of replicating cells, where it exhibits reduced genotoxicity compared to 5-ethynyl-2'-deoxyuridine (EdU). The VdU-tetrazine ligation reaction is rapid (k≈0.02 M(-1) s(-1)) and chemically orthogonal to the alkyne-azide "click" reaction of EdU-modified DNA. Alkene-tetrazine ligation reactions provide the first alternative to azide-alkyne click reactions for the bioorthogonal chemical labeling of nucleic acids in cells and facilitate time-resolved, multicolor labeling of DNA synthesis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Reactions of buffers in cyanogen bromide-induced ligations.

    PubMed

    Vogel, Heike; Gerlach, Claudia; Richert, Clemens

    2013-01-01

    Rapid, template-directed ligation reactions between a phosphate-terminated oligonucleotide and an unphosphorylated reaction partner may be induced by cyanogen bromide (BrCN). Frequently, however, the reaction is low yielding, and even a large excess of the condensing agent can fail to induce quantitative conversions. In this study, we used BrCN to induce chemical primer extension reactions. Here, we report that buffers containing hydroxyl groups react with short oligodeoxynucleotides in the presence of BrCN. One stable adduct between HEPBS buffer and cytosine was characterized by mass spectrometry and NMR after HPLC purification, indicating that a side reaction occurred at this nucleobase. Further, a first example of a primer extension reaction between an unmodified oligodeoxynucleotide as primer and dGMP is reported. Together, our results shed light on the potency, as well as the drawbacks of BrCN as a highly reactive condensing reagent for the ligation of unmodified nucleic acids.

  18. Tubal ligation and the risk of ovarian carcinoma.

    PubMed

    Cornelison, T L; Natarajan, N; Piver, M S; Mettlin, C J

    1997-01-01

    To assess the relationship of tubal ligation and risk of ovarian carcinoma, we conducted a case-control, retrospective analysis of 300 ovarian carcinoma cases and 606 nonmalignant disease controls, seen between 1982 and 1988 at Roswell Park Cancer Institute, Buffalo, New York. Women who had a tubal ligation had reduced risk for the development of ovarian cancer. This relative risk was 0.52, with a 95% confidence interval 0.31 to 0.85 (p = 0.0076). Controls were matched by age. Multivariate analysis adjusted for socioeconomic level, marital status, parity, age at first pregnancy, menarche age, menopause age, irregular menses, breast-feeding duration, body habitus, and oral contraceptive use. Suggested explanations for this observation are offered.

  19. Click chemistry for rapid labeling and ligation of RNA.

    PubMed

    Paredes, Eduardo; Das, Subha R

    2011-01-03

    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.

  20. Is ligation the only solution to the pyrophosphate problem?

    NASA Technical Reports Server (NTRS)

    Visscher, J.; Jongbloets, R.; Schwartz, Alan W.

    1993-01-01

    Pyrophosphate linkages are easily formed during the nonenzymatic oligomerization of activated nucleotides. They often form `caps' which terminate an oligonucleotide with a 5'-5' pyrophosphate. Owing to their structural resemblance to the intermediates in enzymatic ligation reactions, it has been suggested that pyrophosphate caps might have been capable of acting as activating groups in chain elongation processes. We argue that an alternative possibility would have been the specific hydrolysis of pyrophosphates.

  1. Is ligation the only solution to the pyrophosphate problem?

    NASA Astrophysics Data System (ADS)

    Visscher, J.; Jongbloets, R.; Schwartz, Alan W.

    1993-12-01

    Pyrophosphate linkages are easily formed during the nonenzymatic oligomerization of activated nucleotides. They often form ‘caps’ which terminate an oligonucleotide with a 5'-5' pyrophosphate. Owing to their structural resemblance to the intermediates in enzymatic ligation reactions, it has been suggested that pyrophosphate caps might have been capable of acting as activating groups in chain elongation processes. We argue that an alternative possibility would have been the specific hydrolysis of pyrophosphates.

  2. Comparison of Hi-C results using in-solution versus in-nucleus ligation.

    PubMed

    Nagano, Takashi; Várnai, Csilla; Schoenfelder, Stefan; Javierre, Biola-Maria; Wingett, Steven W; Fraser, Peter

    2015-08-26

    Chromosome conformation capture and various derivative methods such as 4C, 5C and Hi-C have emerged as standard tools to analyze the three-dimensional organization of the genome in the nucleus. These methods employ ligation of diluted cross-linked chromatin complexes, intended to favor proximity-dependent, intra-complex ligation. During development of single-cell Hi-C, we devised an alternative Hi-C protocol with ligation in preserved nuclei rather than in solution. Here we directly compare Hi-C methods employing in-nucleus ligation with the standard in-solution ligation. We show in-nucleus ligation results in consistently lower levels of inter-chromosomal contacts. Through chromatin mixing experiments we show that a significantly large fraction of inter-chromosomal contacts are the result of spurious ligation events formed during in-solution ligation. In-nucleus ligation significantly reduces this source of experimental noise, and results in improved reproducibility between replicates. We also find that in-nucleus ligation eliminates restriction fragment length bias found with in-solution ligation. These improvements result in greater reproducibility of long-range intra-chromosomal and inter-chromosomal contacts, as well as enhanced detection of structural features such as topologically associated domain boundaries. We conclude that in-nucleus ligation captures chromatin interactions more consistently over a wider range of distances, and significantly reduces both experimental noise and bias. In-nucleus ligation creates higher quality Hi-C libraries while simplifying the experimental procedure. We suggest that the entire range of 3C applications are likely to show similar benefits from in-nucleus ligation.

  3. Immunodesign of experimental sepsis by cecal ligation and puncture

    PubMed Central

    Rittirsch, Daniel; Huber-Lang, Markus S; Flierl, Michael A; Ward, Peter A

    2009-01-01

    Sepsis remains a prevalent clinical challenge and the underlying pathophysiology is still poorly understood. To investigate the complex molecular mechanisms of sepsis, various animal models have been developed, the most frequently used being the cecal ligation and puncture (CLP) model in rodents. In this model, sepsis originates from a polymicrobial infectious focus within the abdominal cavity, followed by bacterial translocation into the blood compartment, which then triggers a systemic inflammatory response. A requirement of this model is that it is performed with high consistency to obtain reproducible results. Evidence is now emerging that the accompanying inflammatory response varies with the severity grade of sepsis, which is highly dependent on the extent of cecal ligation. In this protocol, we define standardized procedures for inducing sepsis in mice and rats by applying defined severity grades of sepsis through modulation of the position of cecal ligation. The CLP procedure can be performed in as little as 10 min for each animal by an experienced user, with additional time required for subsequent postoperative care and data collection. PMID:19131954

  4. DNA hybridization and ligation for directed colloidal assembly

    NASA Astrophysics Data System (ADS)

    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

  5. Low Cost RF Amplifier for Community TV

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

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

  6. Does surface roughness amplify wetting?

    SciTech Connect

    Malijevský, Alexandr

    2014-11-14

    Any solid surface is intrinsically rough on the microscopic scale. In this paper, we study the effect of this roughness on the wetting properties of hydrophilic substrates. Macroscopic arguments, such as those leading to the well-known Wenzel's law, predict that surface roughness should amplify the wetting properties of such adsorbents. We use a fundamental measure density functional theory to demonstrate the opposite effect from roughness for microscopically corrugated surfaces, i.e., wetting is hindered. Based on three independent analyses we show that microscopic surface corrugation increases the wetting temperature or even makes the surface hydrophobic. Since for macroscopically corrugated surfaces the solid texture does indeed amplify wetting there must exist a crossover between two length-scale regimes that are distinguished by opposite response on surface roughening. This demonstrates how deceptive can be efforts to extend the thermodynamical laws beyond their macroscopic territory.

  7. Transverse Bragg resonance laser amplifier.

    PubMed

    Yariv, Amnon; Xu, Yong; Mookherjea, Shayan

    2003-02-01

    We propose and analyze a new type of optical amplifier that is formed by addition of gain in the periodic cladding of a transverse Bragg resonance waveguide [Opt. Lett. 27, 936 (2002)]. Using the coupled-wave formalism, we calculate the mode profiles, the exponential gain constant, and, for comparison, the gain enhancement compared with those of conventional semiconductor optical amplifiers. In contrast with coupled-mode theory, in one-dimensional structures (e.g., the distributed-feedback laser) the exponential gain constant in the longitudinal direction is involved in both longitudinal and transverse confinement, and its solution has to be achieved self-consistently, together with the quantized guiding channel width.

  8. High temperature current mirror amplifier

    DOEpatents

    Patterson, III, Raymond B.

    1984-05-22

    A high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current mirror is provided with a biasing means and current means on the input leg.

  9. 338-GHz Semiconductor Amplifier Module

    NASA Technical Reports Server (NTRS)

    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

    2010-01-01

    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.

  10. High power gas laser amplifier

    DOEpatents

    Leland, Wallace T.; Stratton, Thomas F.

    1981-01-01

    A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

  11. Compact, harmonic multiplying gyrotron amplifiers

    SciTech Connect

    Guo, H.Z.; Granatstein, V.L.; Antonsen, T.M. Jr.; Levush, B.; Tate, J.; Chen, S.H.

    1995-12-31

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

  12. High power regenerative laser amplifier

    DOEpatents

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

    1994-02-08

    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.

  13. High power regenerative laser amplifier

    DOEpatents

    Miller, John L.; Hackel, Lloyd A.; Dane, Clifford B.; Zapata, Luis E.

    1994-01-01

    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.

  14. Small and lightweight power amplifiers

    NASA Astrophysics Data System (ADS)

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

    2002-07-01

    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.

  15. Highly stable biased amplifier and stretcher system

    NASA Technical Reports Server (NTRS)

    Roddick, R. G.

    1970-01-01

    Amplifier and stretcher system, which minimizes thermal effects and compensates for repetition-rate effects, maintains resolution levels in spectrum analysis. An additional inverting amplifier is used in the system to provide a noiseless charge restorer.

  16. Surgical ligation of patent ductus arteriosus in premature infants: trends and practice variation.

    PubMed

    Weinberg, Jacqueline G; Evans, Frank J; Burns, Kristin M; Pearson, Gail D; Kaltman, Jonathan R

    2016-08-01

    We sought to analyse the variation in the incidence of patent ductus arteriosus over three recent time points and characterise ductal ligation practices in preterm infants in the United States, adjusting for demographic and morbidity factors. Using the Kids' Inpatient Database from 2003, 2006, and 2009, we identified infants born at ⩽32 weeks of gestation with International Classification of Diseases, Ninth Revision diagnosis of patent ductus arteriosus and ligation code. We examined patient and hospital characteristics and identified patient and hospital variables associated with ligation. Of 182,610 preterm births, 30,714 discharges included a patent ductus arteriosus diagnosis. The rate of patent ductus arteriosus diagnosis increased from 14% in 2003 to 21% in 2009 (p<0.001). A total of 4181 ligations were performed, with an overall ligation rate of 14%. Ligation rate in infants born at ⩽28 weeks of gestation was 20% overall, increasing from 18% in 2003 to 21% in 2009 (p<0.001). The ligation rate varied by state (4-28%), and ligation was associated with earlier gestational age, associated diagnoses, hospital type, teaching hospital status, and region (p<0.001). The rates of patent ductus arteriosus diagnosis and ligation have increased in the recent years. Variation exists in the practice of patent ductus arteriosus ligation and is influenced by patient and non-patient factors.

  17. NASA developments in solid state power amplifiers

    NASA Technical Reports Server (NTRS)

    Leonard, Regis F.

    1990-01-01

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

  18. Solid state, S-band, power amplifier

    NASA Technical Reports Server (NTRS)

    Digrindakis, M.

    1973-01-01

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

  19. Remote Acquisition Amplifier For 50-Ohm Cable

    NASA Technical Reports Server (NTRS)

    Amador, Jose J.

    1995-01-01

    Buffer-amplifier unit designed to drive 50-Ohm cables up to 100 ft. (30 m) long, compensating for attenuation in cables and enabling remote operation of oscilloscopes. Variable resistor provides for adjustment of gain of amplifier, such that overall gain from input terminals of amplifier to output end of cable set to unity.

  20. Log amplifier with pole-zero compensation

    DOEpatents

    Brookshier, William

    1987-01-01

    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.

  1. Functional Electronic Amplifiers with Broad Dynamic Band,

    DTIC Science & Technology

    1983-09-27

    dynamic properties of amplifiers, assembled on this type of amplifier instruments, it is expedient to introduce the concept of the dynamic quality...qjvL> ql. 3. Amplifier has data: K" =K’/m; , vus,, q -q4cujvv.4 in Fig. 1). Functional amplifier is assembled on the block diagram Fig. 2b. It has...following data: K-mr’ vv;m-v-mvv’-" qpYmq j° ey" As can be seen from the given examples, dynamic quality of FU, assembled on the identical amplifier

  2. HIGH AVERAGE POWER OPTICAL FEL AMPLIFIERS.

    SciTech Connect

    BEN-ZVI, ILAN, DAYRAN, D.; LITVINENKO, V.

    2005-08-21

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

  3. Modern tools for the chemical ligation and synthesis of modified peptides and proteins.

    PubMed

    Gentilucci, Luca; Tosi, Pierluigi; Bauer, Adriano; Marco, Rossella De

    2016-12-01

    The ability to improve nature's capacity by introducing modification of biological interest in proteins and peptides (P&P) is one of the modern challenges in synthetic chemistry. Due to the unfavorable pharmacokinetic properties, many native P&P are of little use as therapeutic agents. Today, few methods for the preparation of modified proteins are available. Initially introduced to realize the ligation between two standard peptidic sequences, and hence to afford native proteins, the modern chemical methodologies, in other words native chemical ligation, expressed ligation, Staudinger ligation, auxiliary mediated ligation, aldehyde capture, etc., can be virtually utilized to ligate a variety of peptidomimetic partners, allowing a systematic access to modified, unnatural large P&P.

  4. The Wexham Criteria: defining severe epistaxis to select patients requiring sphenopalatine artery ligation.

    PubMed

    Lakhani, Raj; Syed, Irfan; Qureishi, Ali; Bleach, Nigel

    2013-07-01

    This study aims to provide guidance regarding patient selection and timing of intervention with sphenopalatine artery (SPA) ligation by defining 'severe epistaxis'. An analysis of all patients undergoing SPA ligation (January 2002-2010) was performed. SPA ligation was deemed necessary if at least one of the four identified criteria was fulfilled. The same analysis was also performed on all patients admitted with epistaxis who did not undergo SPA ligation over a 6-month period. All 27 patients who underwent SPA ligation met at least one of the criteria selected. Uncontrolled epistaxis (21/27) was fulfilled most often. In comparison, only 4/71 patients admitted with epistaxis who did not undergo SPA ligation fulfilled any single criterion. All criteria were satisfied in a significantly higher number of cases in the SPA group (p < 0.001) The criteria studied proved helpful in identifying patients admitted to hospital with epistaxis who had failed conservative measures.

  5. Tuboplasty as a reversal macrosurgery for tubal ligation, is pregnancy possible? A case series

    PubMed Central

    Yassaee, Fakhrolmolouk

    2014-01-01

    Background: Reversal of tubal ligation is requested by some women for various reasons. The present study aims to determine the rate of pregnancy after tubal ligation reversal. Case: In these case series, we reported fifteen women who requested tuboplasty after tubal ligation. In these cases reversal of tubal ligation was done in 15 women. Pregnancy occurred in 4 women (26.6%). Two term pregnancy and 2 abortions were determined. Conclusion: The success rate of pregnancy after macro surgical reversal of tubal ligation is good and can be considered before in vitro fertilization. The type of tubal ligation and the procedure used will determine the best procedure for reversal and have a major impact on chance of success for reversal surgery. PMID:25031582

  6. In Vitro Selection of Optimal DNA Substrates for Ligation by a Water-Soluble Carbodiimide

    NASA Technical Reports Server (NTRS)

    Harada, Kazuo; Orgel, Leslie E.

    1994-01-01

    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.

  7. In Vitro Selection of Optimal DNA Substrates for Ligation by a Water-Soluble Carbodiimide

    NASA Technical Reports Server (NTRS)

    Harada, Kazuo; Orgel, Leslie E.

    1994-01-01

    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.

  8. ULTRA-STABILIZED D. C. AMPLIFIER

    DOEpatents

    Hartwig, E.C.; Kuenning, R.W.; Acker, R.C.

    1959-02-17

    An improved circuit is described for stabilizing the drift and minimizing the noise and hum level of d-c amplifiers so that the output voltage will be zero when the input is zero. In its detailed aspects, the disclosed circuit incorporates a d-c amplifier having a signal input, a second input, and an output circuit coupled back to the first input of the amplifier through inverse feedback means. An electronically driven chopper having a pair of fixed contacts and a moveable contact alternately connects the two inputs of a difference amplifier to the signal input. The A. E. error signal produced in the difference amplifier is amplified, rectified, and applied to the second input of the amplifier as the d-c stabilizing voltage.

  9. Nondegenerate optical parametric chirped pulse amplifier

    DOEpatents

    Jovanovic, Igor; Ebbers, Christopher A.

    2005-03-22

    A system provides an input pump pulse and a signal pulse. A first dichroic beamsplitter is highly reflective for the input signal pulse and highly transmissive for the input pump pulse. A first optical parametric amplifier nonlinear crystal transfers part of the energy from the input pump pulse to the input signal pulse resulting in a first amplified signal pulse and a first depleted pump pulse. A second dichroic beamsplitter is highly reflective for the first amplified signal pulse and highly transmissive for the first depleted pump pulse. A second optical parametric amplifier nonlinear crystal transfers part of the energy from the first depleted pump pulse to the first amplified signal pulse resulting in a second amplified signal pulse and a second depleted pump pulse. A third dichroic beamsplitter receives the second amplified signal pulse and the second depleted pump pulse. The second depleted pump pulse is discarded.

  10. Direct solar-pumped iodine laser amplifier

    NASA Technical Reports Server (NTRS)

    Han, K. S.

    1985-01-01

    This semiannual progress report covers the period from April 1, 1985 to Sept. 30, 1985 under NASA grant NAS1-441 entitled direct solar pumped iodine laser amplifier. During this period the parametric studies of the iodine laser oscillator pumped by a Vortek simulator was carried out before the amplifier studies. The amplifier studies are postponed to the extended period following completion of the parametric studies. In addition, the kinetic modeling of a solar pumped iodine laser amplifier, and the experimental work for a solar pumped dye laser amplifier are in progress. This report contains three parts: (1) the radiation characteristics of solar simulator and the parametric characteristics of photodissociation iodine laser continuously pumped by a Vortek solar simulator; (2) kinetic modeling of a solar pumped iodine laser amplifier; and (3) the study of the dye laser amplifier pumped by a Tamarack solar simulator.

  11. High temperature charge amplifier for geothermal applications

    DOEpatents

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

    2015-12-08

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

  12. High temperature current mirror amplifier

    DOEpatents

    Patterson, R.B. III.

    1984-05-22

    Disclosed is a high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current mirror is provided with a biasing means and current means on the input leg. 2 figs.

  13. Charge amplifier with bias compensation

    DOEpatents

    Johnson, Gary W.

    2002-01-01

    An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

  14. Anal function after ligation of the intersphincteric fistula tract.

    PubMed

    Tsunoda, Akira; Sada, Haruki; Sugimoto, Takuya; Nagata, Hiroshi; Kano, Nobuyasu

    2013-07-01

    Although the ligation of the intersphincteric fistula tract is a promising anal sphincter-saving procedure for fistula-in-ano, the objective assessment of the sphincter preservation remains unknown. The primary end point was to measure the anal function before and after this procedure. The secondary end point measured was cure of the disease. This study is a prospective observational study. This study was conducted at the Department of Surgery, Kameda Medical Center, Japan, from March 2010 to August 2012. Twenty patients with transsphincteric or complex fistulas were evaluated. All patients underwent the ligation of the intersphincteric fistula tract with a loose seton for anal fistulas. Anal manometric study was performed before and 3 months after the procedure. Fecal incontinence was evaluated by using the fecal incontinence severity index. Failure was defined as nonhealing of the surgical wound or fistula. The median operation time was 42 minutes. No intraoperative complications were documented. The median follow-up duration was 18 (3-32) months. No patients reported any incontinence postoperatively. The median score of the fecal incontinence severity index before and 3 months after the procedure was 0. The median maximum resting pressure measured before and after operation were 125 (71-175) cm H2O and 133 (95-169) cm H2O. The median maximum squeeze pressure measured before and after operation were 390 (170-815) cm H2O and 432 (200-902) cm H2O. There were no significant postoperative changes in either the resting pressure or the squeeze pressure. Primary healing was observed in 19 (95%) patients, and the median healing time was 7 weeks; 1 wound remained incompletely healed. Short-term follow-up may not justify the use of the term definitive cure. The ligation of the intersphincteric fistula tract with a loose seton showed no postoperative deterioration on anal sphincter function with favorable healing rates.

  15. Menstrual Pattern following Tubal Ligation: A Historical Cohort Study

    PubMed Central

    Sadatmahalleh, Shahideh Jahanian; Ziaei, Saeideh; Kazemnejad, Anoshirvan; Mohamadi, Eesa

    2016-01-01

    Background Tubal ligation (TL) is recommended for women who have completed their family planning. The existence of the menstrual disorders following this procedure has been the subject of debate for decades. This study was conducted to identify the relationship between tubal ligation and menstrual disorders. Materials and Methods A historical cohort study was carried out on 140 women undergoing tubal ligation (TL group) and on 140 women using condom as the main contraceptive method (Non-TL group). They aged between 20 and 40 years and were selected from a health care center in Rudsar, Guilan Province, Iran, during 2013-2014. The two groups were comparable in demographic characteristics, obstetrical features and menstrual bleeding pattern using a routine questionnaire. A validated pictorial blood loss assessment chart (PBLAC) was also used to measure the menstrual blood loss. Results Women with TL had more menstrual irregularity than those without TL (24.3 vs. 10%, P=0.002). Women with TL had more polymenorrhea (9.3 vs. 1.4%, P=0.006), hypermenorrhea (12.1 vs. 2.1%, P=0.002), menorrhagia (62.9 vs. 22.1%, P<0.0001) and menometrorrhagia (15.7 vs. 3.6%, P=0.001) than those without TL. There is a significant difference in the PBLAC score between women with and without TL (P<0.0001). According to logistic regression, age odds ratio [(OR=1.08, con- fidence interval (CI):1.07-1.17, P=0.03)], TL (OR=5.95, CI:3.45-10.26, P<0.0001) and cesarean section (OR=2.72, CI:1.49-4.97, P=0.001) were significantly associated with menorrhagia. Conclusion We found significant differences in menstrual disorders between women with and without TL. Therefore, women should be informed by the health providers regarding the advantages and disadvantages of TL before the procedures. PMID:26985334

  16. Successful Thoracic Duct Ligation for Plastic Bronchitis in an Adult.

    PubMed

    Hess, Nicholas R; Piercecchi, Christopher; Desai, Nikita; Fisher, Micah R; Lee, Eun-Hyung; Force, Seth D

    2017-06-01

    Plastic bronchitis is a rare and potentially life-threatening disease characterized by the development of obstructive fibrinous tracheobronchial casts and hypoxic respiratory failure. With its poorly understood cause and rare occurrence in the adult population, few treatment strategies have been described in adults with this condition. In this report, we present a case of successful treatment of an adult with plastic bronchitis, using thoracic duct ligation and resulting in full resolution of airway cast development. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  17. Post-functionalization of polymers via orthogonal ligation chemistry.

    PubMed

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

    2013-05-27

    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.

  18. Evaluation of Micro-organism in Ligated Metal and Self-ligating Brackets using Scanning Electron Microscopy: An In Vivo Study.

    PubMed

    Sunil, P C; Michael, Tony; Raju, Aravind S; Paul, Renji K; Mamatha, J; Ebin, T M

    2015-07-01

    The objective of the study was to determine the sites of plaque accumulation and to compare the plaque accumulated with metal and self-ligating orthodontic brackets in order to know which bracket type had a higher plaque retaining capacity. The study was done on 20 subjects who were scheduled for orthodontic treatment including extraction of four premolars and fixed orthodontic appliances. Mesh-backed edgewise metal brackets ligated with steel ligatures and self-ligating brackets were bonded to the premolars to be extracted using composite (Transbond XT, 3M). The subjects were told to continue their normal oral hygiene regimen. Teeth were extracted at 1, 2, and 3 weeks after bracket bonding. Plaque attached to the buccal surfaces was stained using plaque disclosing agent. The teeth were then immersed in fixative containing 4% formaldehyde and 1% glutaraldehyde in phosphate buffer for 24 h, followed by 0.1 M phosphate buffer for 12 h. The specimens were then mounted on aluminum stubs, and sputter coated with gold prior to Scanning electron microscopy examination. The results showed that increased retention of plaque in metal brackets ligated with steel ligatures and comparatively less in self-ligating brackets at the base of the brackets. This study highlights that higher retention of plaque in metal brackets ligated with steel ligatures and comparatively less plaque retention in self-ligating brackets. Excess composite around the bracket base is the critical site of plaque accumulation associated with fixed appliances due to its rough surface texture.

  19. High power RF solid state power amplifier system

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  20. Binding-regulated click ligation for selective detection of proteins.

    PubMed

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

    2016-04-15

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Calcium Ligation in Photosystem II under Inhibiting Conditions

    PubMed Central

    Barry, Bridgette A.; Hicks, Charles; De Riso, Antonio; Jenson, David L.

    2005-01-01

    In oxygenic photosynthesis, PSII carries out the oxidation of water and reduction of plastoquinone. The product of water oxidation is molecular oxygen. The water splitting complex is located on the lumenal side of the PSII reaction center and contains manganese, calcium, and chloride. Four sequential photooxidation reactions are required to generate oxygen from water; the five sequentially oxidized forms of the water splitting complex are known as the Sn states, where n refers to the number of oxidizing equivalents stored. Calcium plays a role in water oxidation; removal of calcium is associated with an inhibition of the S state cycle. Although calcium can be replaced by other cations in vitro, only strontium maintains activity, and the steady-state rate of oxygen evolution is decreased in strontium-reconstituted PSII. In this article, we study the role of calcium in PSII that is limited in water content. We report that strontium substitution or 18OH2 exchange causes conformational changes in the calcium ligation shell. The conformational change is detected because of a perturbation to calcium ligation during the S1 to S2 and S2 to S3 transition under water-limited conditions. PMID:15985425

  2. Enzyme-linked electrochemical DNA ligation assay using magnetic beads.

    PubMed

    Stejskalová, Eva; Horáková, Petra; Vacek, Jan; Bowater, Richard P; Fojta, Miroslav

    2014-07-01

    DNA ligases are essential enzymes in all cells and have been proposed as targets for novel antibiotics. Efficient DNA ligase activity assays are thus required for applications in biomedical research. Here we present an enzyme-linked electrochemical assay based on two terminally tagged probes forming a nicked junction upon hybridization with a template DNA. Nicked DNA bearing a 5' biotin tag is immobilized on the surface of streptavidin-coated magnetic beads, and ligated product is detected via a 3' digoxigenin tag recognized by monoclonal antibody-alkaline phosphatase conjugate. Enzymatic conversion of napht-1-yl phosphate to napht-1-ol enables sensitive detection of the voltammetric signal on a pyrolytic graphite electrode. The technique was tested under optimal conditions and various situations limiting or precluding the ligation reaction (such as DNA substrates lacking 5'-phosphate or containing a base mismatch at the nick junction, or application of incompatible cofactor), and utilized for the analysis of the nick-joining activity of a range of recombinant Escherichia coli DNA ligase constructs. The novel technique provides a fast, versatile, specific, and sensitive electrochemical assay of DNA ligase activity.

  3. TLR9 ligation in pancreatic stellate cells promotes tumorigenesis

    PubMed Central

    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

    2015-01-01

    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. PMID:26481685

  4. TLR9 ligation in pancreatic stellate cells promotes tumorigenesis.

    PubMed

    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

    2015-11-16

    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.

  5. Ligation of complement receptor 1 increases erythrocyte membrane deformability.

    PubMed

    Glodek, Aleksandra M; Mirchev, Rossen; Golan, David E; Khoory, Joseph A; Burns, Jennie M; Shevkoplyas, Sergey S; Nicholson-Weller, Anne; Ghiran, Ionita C

    2010-12-23

    Microbes as well as immune complexes and other continuously generated inflammatory particles are efficiently removed from the human circulation by red blood cells (RBCs) through a process called immune-adherence clearance. During this process, RBCs use complement receptor 1 (CR1, CD35) to bind circulating complement-opsonized particles and transfer them to resident macrophages in the liver and spleen for removal. We here show that ligation of RBC CR1 by antibody and complement-opsonized particles induces a transient Ca(++) influx that is proportional to the RBC CR1 levels and is inhibited by T1E3 pAb, a specific inhibitor of TRPC1 channels. The CR1-elicited RBC Ca(++) influx is accompanied by an increase in RBC membrane deformability that positively correlates with the number of preexisting CR1 molecules on RBC membranes. Biochemically, ligation of RBC CR1 causes a significant increase in phosphorylation levels of β-spectrin that is inhibited by preincubation of RBCs with DMAT, a specific casein kinase II inhibitor. We hypothesize that the CR1-dependent increase in membrane deformability could be relevant for facilitating the transfer of CR1-bound particles from the RBCs to the hepatic and splenic phagocytes.

  6. Development of hepatorenal syndrome in bile duct ligated rats

    PubMed Central

    Pereira, Regina M; dos Santos, Robson AS; Oliveira, Eduardo A; Leite, Virgínia HR; Dias, Filipi LC; Rezende, Alysson S; Costa, Lincoln P; Barcelos, Lucíola S; Teixeira, Mauro M; Silva, Ana Cristina Simões e

    2008-01-01

    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. PMID:18680230

  7. Intermediate endocrine-acinar pancreatic cells in duct ligation conditions.

    PubMed

    Bertelli, E; Bendayan, M

    1997-11-01

    When tissues were subjected to 24 h of duct ligation, intermediate pancreatic cells simultaneously displaying endocrine and exocrine phenotypes appeared. Immunocytochemistry by laser scanning confocal microscopy revealed the appearance of a large number of these cells coexpressing insulin and amylase. These cells were located within the islets of Langerhans as well as in the acinar parenchyma. They were also detected in a culture system of isolated pancreatic cells. With the use of immunoelectron microscopy, two types of secretory granules were identified in these cells. One was insulin immunoreactive, whereas the other, resembling zymogen granules, contained amylase. Occasionally, some small granules displayed a double labeling for both secretory proteins. Numerous crinophagic bodies and autophagosomes containing insulin and/or amylase were also present. In situ hybridization, applied with the specific probes, confirmed the presence of both insulin and amylase mRNAs in these cells. Because duct ligation is known to induce insulin cell proliferation, the present results confirm that endocrine-acinar cells do appear in such condition and may represent intermediate steps in a transdifferentiating process.

  8. Signal-Conditioning Amplifier Recorders

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro J.; Taylor, John

    2003-01-01

    Signal-conditioning amplifier recorders (SCAmpRs) have been proposed as a means of simplifying and upgrading the Kennedy Space Center (KSC) Ground Measurement System (GMS), which is a versatile data-acquisition system that gathers and records a variety of measurement data before and during the launch of a space shuttle. In the present version of the GMS system, signal conditioning amplifiers digitize and transmit data to a VME chassis that multiplexes up to 416 channels. The data is transmitted via a high-speed data bus to a second VME chassis where it is available for snapshots. The data is passed from the second VME chassis to a high-speed data recorder. This process is duplicated for installations at two launch pads and the Vehicle Assembly Building (VAB). Since any failure of equipment in the data path results in loss of data, much of the system is redundant. The architecture of the existing GMS limits expansion or any modification to the system to meet changing requirements because of the cost and time required. A SCAmpR-based system is much more flexible. The basis of the simplification, flexibility, and reliability is the shifting of the recording function to the individual amplifier channels. Each SCAmpR is a self-contained single channel data acquisition system, which in its current implementation, has a data storage capacity of up to 30 minutes when operating at the fastest data sampling rates. The SCAmpR channels are self-configuring and self-calibrating. Multiple SCAmpR channels are ganged on printed circuit boards and mounted in a chassis that provides power, a network hub, and Inter-Range Instrument Group (IRIG) time signals. The SCAmpR channels share nothing except physical mounting on a circuit board. All circuitry is electrically separate for each channel. All that is necessary to complete the data acquisition system is a single master computer tied to the SCAmpR channels by standard network equipment. The size of the data acquisition system

  9. High-efficiency solid state power amplifier

    NASA Technical Reports Server (NTRS)

    Wallis, Robert E. (Inventor); Cheng, Sheng (Inventor)

    2005-01-01

    A high-efficiency solid state power amplifier (SSPA) for specific use in a spacecraft is provided. The SSPA has a mass of less than 850 g and includes two different X-band power amplifier sections, i.e., a lumped power amplifier with a single 11-W output and a distributed power amplifier with eight 2.75-W outputs. These two amplifier sections provide output power that is scalable from 11 to 15 watts without major design changes. Five different hybrid microcircuits, including high-efficiency Heterostructure Field Effect Transistor (HFET) amplifiers and Monolithic Microwave Integrated Circuit (MMIC) phase shifters have been developed for use within the SSPA. A highly efficient packaging approach enables the integration of a large number of hybrid circuits into the SSPA.

  10. Multistaged stokes injected Raman capillary waveguide amplifier

    DOEpatents

    Kurnit, Norman A.

    1980-01-01

    A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

  11. Fiber networks amplify active stress

    PubMed Central

    Ronceray, Pierre; Broedersz, Chase P.

    2016-01-01

    Large-scale force generation is essential for biological functions such as cell motility, embryonic development, and muscle contraction. In these processes, forces generated at the molecular level by motor proteins are transmitted by disordered fiber networks, resulting in large-scale active stresses. Although these fiber networks are well characterized macroscopically, this stress generation by microscopic active units is not well understood. Here we theoretically study force transmission in these networks. We find that collective fiber buckling in the vicinity of a local active unit results in a rectification of stress towards strongly amplified isotropic contraction. This stress amplification is reinforced by the networks’ disordered nature, but saturates for high densities of active units. Our predictions are quantitatively consistent with experiments on reconstituted tissues and actomyosin networks and shed light on the role of the network microstructure in shaping active stresses in cells and tissue. PMID:26921325

  12. Resonant isolator for maser amplifier

    NASA Technical Reports Server (NTRS)

    Clauss, R. C.; Quinn, R. B. (Inventor)

    1983-01-01

    An isolator is described for use in a low noise maser amplifier, which provides low loss across a wide bandwidth and which can be constructed at moderate cost. The isolator includes a train of garnet or ferrite elements extending along the length of a microwave channel parallel to the slow wave structure, with the elements being of staggered height, so that the thin elements which are resonant to the microwaves are separated by much thicker elements. The thick garnet or ferrite elements reduce the magnetic flux passing through the thin elements to permit altering of the shape of the thin elements so as to facilitate their fabrication and to provide better isolation with reduced loss, by increasing the thickness of the thin elements and decreasing their length and width.

  13. Transverse pumped laser amplifier architecture

    DOEpatents

    Bayramian, Andrew James; Manes, Kenneth R.; Deri, Robert; Erlandson, Alvin; Caird, John; Spaeth, Mary L.

    2015-05-19

    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.

  14. Transverse pumped laser amplifier architecture

    DOEpatents

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

    2013-07-09

    An optical gain architecture includes a pump source and a pump aperture. The architecture also includes a gain region including a gain element operable to amplify light at a laser wavelength. The gain region is characterized by a first side intersecting an optical path, a second side opposing the first side, a third side adjacent the first and second sides, and a fourth side opposing the third side. The architecture further includes a dichroic section disposed between the pump aperture and the first side of the gain region. The dichroic section is characterized by low reflectance at a pump wavelength and high reflectance at the laser wavelength. The architecture additionally includes a first cladding section proximate to the third side of the gain region and a second cladding section proximate to the fourth side of the gain region.

  15. Resonantly amplified vibronic symmetry breaking

    NASA Astrophysics Data System (ADS)

    Poliakoff, E. D.; Rathbone, G. J.; Bozek, J. D.; Lucchese, R. R.

    2002-05-01

    In photoelectron spectroscopy, it is normally assumed that excitation of a single quantum of a non-totally symmetric vibrational mode is forbidden owing to symmetry constraints. Using vibrationally resolved photoelectron spectroscopy over a broad spectral range, we have shown that a previously overlooked mechanism can lead to these nominally forbidden transitions. Specifically, the photoelectron can mediate the oscillator strength for such a transition via resonantly amplified vibronic symmetry breaking, and this effect results from intrachannel rather than interchannel coupling. In our first experiments, we focused on bending excitation accompanying CO2 photoionization. Photoelectron spectroscopy on the CO_2^+(C^2Σ_g^+) state showed that the excitation of the (010) vibrational mode is mediated by a shape resonant continuum electron. The degree of vibrational excitation can be substantial, and extensions to other types of symmetry breaking are currently being investigated.

  16. Hydraulically amplified PZT mems actuator

    DOEpatents

    Miles, Robin R.

    2004-11-02

    A hydraulically amplified microelectromechanical systems actuator. A piece of piezoelectric material or stacked piezo bimorph is bonded or deposited as a thin film. The piece is operatively connected to a primary membrane. A reservoir is operatively connected to the primary membrane. The reservoir contains a fluid. A membrane is operatively connected to the reservoir. In operation, energizing the piezoelectric material causing the piezoelectric material to bow. Bowing of the piezoelectric material causes movement of the primary membrane. Movement of the primary membrane results in a force in being transmitted to the liquid in the reservoir. The force in the liquid causes movement of the membrane. Movement of the membrane results in an operating actuator.

  17. A THEORY FOR BROADBAND VARACTOR PARAMETRIC AMPLIFIERS

    DTIC Science & Technology

    This thesis is concerned with the development of a general and rigorous broadbanding theory for varactor parametric amplifiers . Fundamental gain...bandwidth limitations of a varactor parametric amplifier are obtained which are independent of the equalizer. Results obtained in this theory lead to the...design and synthesis of broadband varactor parametric amplifiers . The circuit considered in this thesis is that of linear variable capacitors embedded

  18. A dc amplifier for nuclear particle measurement

    NASA Technical Reports Server (NTRS)

    Macnee, A. B.; Masnari, N. A.

    1978-01-01

    A monolithic preamplifier-postamplifier combination has been developed for use with solid state particle detectors. The direct coupled amplifiers employ interdigitated n-channel JFET's, diodes, and diffused resistors. The circuits developed demonstrate the feasibility of matching the performance of existing discrete component designs. The fabrication procedures for the monolithic amplifier fabrication are presented and the results of measurements on a limited number of sample amplifiers are given.

  19. Class E/F switching power amplifiers

    NASA Technical Reports Server (NTRS)

    Hajimiri, Seyed-Ali (Inventor); Aoki, Ichiro (Inventor); Rutledge, David B. (Inventor); Kee, Scott David (Inventor)

    2004-01-01

    The present invention discloses a new family of switching amplifier classes called class E/F amplifiers. These amplifiers are generally characterized by their use of the zero-voltage-switching (ZVS) phase correction technique to eliminate of the loss normally associated with the inherent capacitance of the switching device as utilized in class-E amplifiers, together with a load network for improved voltage and current wave-shaping by presenting class-F.sup.-1 impedances at selected overtones and class-E impedances at the remaining overtones. The present invention discloses a several topologies and specific circuit implementations for achieving such performance.

  20. Log amplifier with pole-zero compensation

    DOEpatents

    Brookshier, W.

    1985-02-08

    A logarithmic amplifier circuit provides pole-zero compensation for improved stability and response time over 6-8 decades of input signal frequency. The amplifer circuit includes a first operational amplifier with a first feedback loop which includes a second, inverting operational amplifier in a second feedstock 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 is offset by a compensating break point or zero.

  1. Retrodiction for optical attenuators, amplifiers, and detectors

    SciTech Connect

    Jedrkiewicz, Ottavia; Loudon, Rodney; Jeffers, John

    2004-09-01

    The transformation that an attenuator makes on the state of an optical field is the time reverse of that of an amplifier. Thus predicting the output state for an amplifier is equivalent to retrodicting the input state of an attenuator. We explore the consequences of this equivalence for simple optical quantum communication channels. One counterintuitive consequence is that the mean number of photons sent into an amplifier as retrodicted from a measurement of the number of output photons does not include the contribution of the amplifier noi0008.

  2. Photoinduced axial ligation and deligation dynamics of nonplanar nickel dodecaarylporphyrins.

    PubMed

    Retsek, Jennifer L; Drain, Charles Michael; Kirmaier, Christine; Nurco, Daniel J; Medforth, Craig J; Smith, Kevin M; Sazanovich, Igor V; Chirvony, Vladimir S; Fajer, Jack; Holten, Dewey

    2003-08-13

    The ground- and excited-state metal-ligand dynamics of nonplanar nickel(II) 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin (NiDPP) and two fluorinated analogues (NiF(20)DPP and NiF(28)DPP) have been investigated using static and time-resolved absorption spectroscopy in toluene and in ligating media that differ in basicity, aromaticity, and steric encumbrance. Because of the electronic and steric consequences of nonplanarity, NiDPP does not bind axial ligands in the ground state, but metal coordination does occur after photoexcitation with multistep dynamics that depend on the properties of the ligand. Following the structural relaxations that occur in all nickel porphyrins within approximately 10 ps, ligand binding to photoexcited NiDPP is progressively longer in pyridine, piperidine, and 3,5-lutidine (25-100 ps) but does not occur at all in 2,6-lutidine in which the ligating nitrogen is sterically encumbered. The transient intermediate that is formed, which nominally could be either a five- or six-coordinate species, also has a ligand-dependent lifetime (200-550 ps). Decay of this intermediate occurs partially via ligand release to re-form the uncoordinated species, in competition with binding of the second axial ligand and/or conformational/electronic relaxations (of a six-coordinate intermediate) to give the ground state of the bis-ligated photoproduct. The finding that the photoproduct channel principally depends on ligand characteristics along with the time-evolving spectra suggests that the transient intermediate may involve a five-coordinate species. In contrast to NiDPP, the fluorinated analogues NiF(20)DPP and NiF(28)DPP do coordinate axial ligands in the ground state but eject them after photoexcitation. Collectively, these results demonstrate the sensitivity with which the electronic and structural characteristics of the macrocycle, substituents, and solvent (ligands) can govern the photophysical and photochemical properties of nonplanar porphyrins

  3. A facile avenue to conductive polymer brushes via cyclopentadiene-maleimide Diels-Alder ligation.

    PubMed

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

    2013-10-07

    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.

  4. Ligation of the hairpin ribozyme in cis induced by freezing and dehydration

    PubMed Central

    KAZAKOV, SERGEI A.; BALATSKAYA, SVETLANA V.; JOHNSTON, BRIAN H.

    2006-01-01

    Although reducing the temperature slows most chemical reactions, freezing can stimulate some reactions by mechanisms that are only partially understood. Here we show that freezing stimulates the self-ligation (circularization) of linear forms of the hairpin ribozyme (HPR) containing 2′,3′-cyclic phosphate and 5′-OH termini. Divalent metal ions (M2+) are not required, but monovalent cations and anions at millimolar concentrations can have various effects on this reaction depending on the specific ion. Under optimal conditions, the observed rate of M2+-independent self-ligation reaches a peak (0.04 min−1) at −10°C with a yield of −60% after 1 h. In contrast, no ligation occurs either at above 0°C or in solutions that remain unfrozen when supercooled to subzero temperatures. Under freezing conditions, the cleavage–ligation equilibrium strongly favors ligation. Besides freezing, evaporation of the aqueous solvent as well as the presence of ethanol at levels of 40% or above can also induce M2+-independent HPR ligation at 25°C. We argue that partial RNA dehydration, which is a common feature of freezing, evaporation, and the presence of ethanol, is a key factor supporting HPR ligation activity at both above- and below-freezing temperatures. In the context of the RNA world hypothesis, freezing-induced ligation is an attractive mechanism by which complex RNAs could have evolved under conditions in which RNA was relatively protected against degradation. PMID:16495237

  5. One-pot native chemical ligation by combination of two orthogonal thioester precursors.

    PubMed

    Asahina, Yuya; Kawakami, Toru; Hojo, Hironobu

    2017-02-09

    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.

  6. Plant Enzymes but Not Agrobacterium VirD2 Mediate T-DNA Ligation In Vitro

    PubMed Central

    Ziemienowicz, Alicja; Tinland, Bruno; Bryant, John; Gloeckler, Veronique; Hohn, Barbara

    2000-01-01

    Agrobacterium tumefaciens, a gram-negative soil bacterium, transfers DNA to many plant species. In the plant cell, the transferred DNA (T-DNA) is integrated into the genome. An in vitro ligation-integration assay has been designed to investigate the mechanism of T-DNA ligation and the factors involved in this process. The VirD2 protein, which is produced in Agrobacterium and is covalently attached to T-DNA, did not, under our assay conditions, ligate T-DNA to a model target sequence in vitro. We tested whether plant extracts could ligate T-DNA to target oligonucleotides in our test system. The in vitro ligation-integration reaction did indeed take place in the presence of plant extracts. This reaction was inhibited by dTTP, indicating involvement of a plant DNA ligase. We found that prokaryotic DNA ligases could substitute for plant extracts in this reaction. Ligation of the VirD2-bound oligonucleotide to the target sequence mediated by T4 DNA ligase was less efficient than ligation of a free oligonucleotide to the target. T-DNA ligation mediated by a plant enzyme(s) or T4 DNA ligase requires ATP. PMID:10938108

  7. Ping-pong auto-zero amplifier with glitch reduction

    DOEpatents

    Larson, Mark R.

    2008-01-22

    A ping-pong amplifier with reduced glitching is described. The ping-pong amplifier includes a nulling amplifier coupled to a switching network. The switching network is used to auto-zero a ping amplifier within a ping-pong amplifier. The nulling amplifier drives the output of a ping amplifier to a proper output voltage level during auto-zeroing of the ping amplifier. By being at a proper output voltage level, glitches associated with transitioning between a ping amplifier and a pong amplifier are reduced or eliminated.

  8. [Is a hysterectomy justifiable to prevent post-tubal ligation syndrome?].

    PubMed

    Maheux, R; Fugère, P

    1980-12-01

    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)

  9. Tubal ligation in relation to menopausal symptoms and breast cancer risk

    PubMed Central

    Nichols, H B; Baird, D D; DeRoo, L A; Kissling, G E; Sandler, D P

    2013-01-01

    Background: Local inflammation after tubal ligation may affect ovarian function and breast cancer risk. Methods: We analysed tubal ligation, menopausal characteristics, and breast cancer risk in the Sister Study cohort (N=50 884 women). Results: Tubal ligation was associated with hot flashes (hazard ratio (HR) 1.09; 95% confidence interval (CI): 1.06–1.12) but not menopausal age (HR 0.99; 95% CI: 0.96–1.02). Tubal ligation did not have an impact on breast cancer overall (HR 0.95; 95% CI: 0.85–1.06), but had a suggested inverse relation with oestrogen receptor+/progesterone receptor+ invasive tumours (HR 0.84; 95% CI: 0.70–1.01), possibly because of subsequent hysterectomy/bilateral oophorectomy. Conclusion: Tubal ligation does not influence overall breast cancer risk. PMID:23922107

  10. Tubal ligation in relation to menopausal symptoms and breast cancer risk.

    PubMed

    Nichols, H B; Baird, D D; DeRoo, L A; Kissling, G E; Sandler, D P

    2013-09-03

    Local inflammation after tubal ligation may affect ovarian function and breast cancer risk. We analysed tubal ligation, menopausal characteristics, and breast cancer risk in the Sister Study cohort (N=50,884 women). Tubal ligation was associated with hot flashes (hazard ratio (HR) 1.09; 95% confidence interval (CI): 1.06-1.12) but not menopausal age (HR 0.99; 95% CI: 0.96-1.02). Tubal ligation did not have an impact on breast cancer overall (HR 0.95; 95% CI: 0.85-1.06), but had a suggested inverse relation with oestrogen receptor+/progesterone receptor+ invasive tumours (HR 0.84; 95% CI: 0.70-1.01), possibly because of subsequent hysterectomy/bilateral oophorectomy. Tubal ligation does not influence overall breast cancer risk.

  11. Left Atrial Appendage Ligation and Exclusion Technology in the Incubator

    PubMed Central

    Syed, Faisal F.; Noheria, Amit; DeSimone, Christopher V.; Asirvatham, Samuel J.

    2016-01-01

    Stroke is the most feared complication of atrial fibrillation (AF). Targeting the left atrial appendage (LAA) mechanically is attractive as a means to simultaneously reduce stroke risk, the need for anticoagulation, and hemorrhagic complications in patients with non-valvular AF. The results of the PROTECT-AF and PREVAIL randomized clinical trials support this approach as a viable therapeutic alternative to warfarin in selected patients and add to accumulating evidence regarding the importance of the LAA in thromboembolism in AF. A number of devices for percutaneous LAA closure are under investigation or development. In this article, key design features of these ligation and exclusion technologies will be discussed, with a focus on aspects of LAA morphology, relational anatomy, thrombosis, and thromboembolism relevant for successful device development and deployment. PMID:27087888

  12. Safe laparoscopic surgery: tubal ligation without prior pneumoperitoneum.

    PubMed

    Biojó, R G; Manzi, G B

    1995-04-01

    Twelve years of experience with tubal ligation by the laparoscopic route at two highly specialized centers of female sterilization are discussed; special attention is given to the technique and results achieved. The number of intraoperative and postoperative complications was very low compared with data reported elsewhere. This article attempts to present the knowledge gained by using the laparoscopic technique, at a time when the use of laparoscopic surgery is extending around the world. The direct insertion of trocars without prior pneumoperitoneum has proved to be safe, and the risks of intraabdominal (visceral or vascular) injuries are minimized by observing simple rules, such as clamping of the relaxed abdominal anterior wall with towel clips, maintaining sharpened trocars, and using the extended index finger as a limit to introduce only the tip of the trocars. We consider a medical history of previous laparotomy secondary to peritonitis and open abdominal treatment absolute contraindications for this technique.

  13. Bioorthogonal Oxime Ligation Mediated In Vivo Cancer Targeting

    PubMed Central

    Tang, Li; Yin, Qian; Xu, Yunxiang; Zhou, Qin; Cai, Kaimin; Yen, Jonathan; Dobrucki, Lawrence W.

    2015-01-01

    Current cancer targeting relying on specific biological interaction between cell surface antigen and respective antibody or its analogue has proven to be effective in the treatment of different cancers; however, this strategy has its own limitations, such as heterogeneity of cancer cells and immunogenicity of the biomacromolecule binding ligands. Bioorthogonal chemical conjugation has emerged as an attractive alternative to biological interaction for in vivo cancer targeting. Here, we report an in vivo cancer targeting strategy mediated by bioorthogonal oxime ligation. Oxyamine group, the artificial target, is introduced onto 4T1 murine breast cancer cells through liposome delivery and fusion. Poly(ethylene glycol) -polylactide (PEG-PLA) nanoparticle (NP) is surface-functionalized with aldehyde groups as targeting ligands. The improved in vivo cancer targeting of PEG-PLA NPs is achieved through specific and efficient chemical reaction between the oxyamine and aldehyde groups. PMID:26146536

  14. In Situ Vesicle Formation by Native Chemical Ligation

    PubMed Central

    Brea, Roberto J.; Cole, Christian M.

    2015-01-01

    Phospholipid vesicles are of intense fundamental and practical interest, yet methods for their de novo generation from reactive precursors are limited. A non-enzymatic and chemoselective method to spontaneously generate phospholipid membranes from water-soluble starting materials would be a powerful tool for generating vesicles and studying lipid membranes. Here we describe the use of native chemical ligation (NCL) to rapidly prepare phospholipids spontaneously from thioesters. While NCL is one of the most popular tools for synthesizing proteins and nucleic acids, to our knowledge this is the first example of using NCL to generate phospholipids de novo. The lipids are capable of in situ synthesis and self-assembly into vesicles that can grow to several microns in diameter. The selectivity of the NCL reaction enables compatibility of in situ membrane formation with biological materials such as proteins. This work expands the application of NCL to the formation of phospholipid membranes. PMID:25346090

  15. Bioorthogonal Oxime Ligation Mediated In Vivo Cancer Targeting.

    PubMed

    Tang, Li; Yin, Qian; Xu, Yunxiang; Zhou, Qin; Cai, Kaimin; Yen, Jonathan; Dobrucki, Lawrence W; Cheng, Jianjun

    2015-04-01

    Current cancer targeting relying on specific biological interaction between cell surface antigen and respective antibody or its analogue has proven to be effective in the treatment of different cancers; however, this strategy has its own limitations, such as heterogeneity of cancer cells and immunogenicity of the biomacromolecule binding ligands. Bioorthogonal chemical conjugation has emerged as an attractive alternative to biological interaction for in vivo cancer targeting. Here, we report an in vivo cancer targeting strategy mediated by bioorthogonal oxime ligation. Oxyamine group, the artificial target, is introduced onto 4T1 murine breast cancer cells through liposome delivery and fusion. Poly(ethylene glycol) -polylactide (PEG-PLA) nanoparticle (NP) is surface-functionalized with aldehyde groups as targeting ligands. The improved in vivo cancer targeting of PEG-PLA NPs is achieved through specific and efficient chemical reaction between the oxyamine and aldehyde groups.

  16. Sensitive detection of aggregated prion protein via proximity ligation

    PubMed Central

    Hammond, Maria; Wik, Lotta; Deslys, Jean-Philippe; Comoy, Emmanuel; Linné, Tommy; Landegren, Ulf; Kamali-Moghaddam, Masood

    2014-01-01

    The DNA assisted solid-phase proximity ligation assay (SP-PLA) provides a unique opportunity to specifically detect prion protein (PrP) aggregates by investigating the collocation of 3 or more copies of the specific protein. We have developed an SP-PLA that can detect PrP aggregates in brain homogenates from infected hamsters even after a 107-fold dilution. In contrast, brain homogenate from uninfected animals did not generate a detectable signal at 100-fold higher concentration. Using either of the 2 monoclonal anti-PrP antibodies, 3F4 and 6H4, we successfully detected low concentrations of aggregated PrP. The presented results provide a proof of concept that this method might be an interesting tool in the development of diagnostic approaches of prion diseases. PMID:25482604

  17. Detection of Protein SUMOylation In Situ by Proximity Ligation Assays.

    PubMed

    Sahin, Umut; Jollivet, Florence; Berthier, Caroline; de Thé, Hugues; Lallemand-Breitenbach, Valérie

    2016-01-01

    Sumoylation is a posttranslational process essential for life and concerns a growing number of crucial proteins. Understanding the influence of this phenomenon on individual proteins or on cellular pathways in which they function has become an intense area of research. A critical step in studying protein sumoylation is to detect sumoylated forms of a particular protein. This has proven to be a challenging task for a number of reasons, especially in the case of endogenous proteins and in vivo studies or when studying rare cells such as stem cells. Proximity ligation assays that allow detection of closely interacting protein partners can be adapted for initial detection of endogenous sumoylation or ubiquitination in a rapid, ultrasensitive, and cheap manner. In addition, modified forms of a given protein can be detected in situ in various cellular compartments. Finally, the flexibility of this technique may allow rapid screening of drugs and stress signals that may modulate protein sumoylation.

  18. [Premature recourse to tubal ligation in Quebec: some undesirable consequences?].

    PubMed

    Marcil-gratton, N

    1987-04-01

    Currently over 40% of fertile aged couples in Quebec have chosen voluntary sterilization as a fertility control method, and it is estimated that nearly 70% of women will be protected by sterilization before the natural end of their reproductive years. Under these circumstances the probability arises that some proportion will come to regret their decision to seek sterilization. Telephone interviews with 497 randomly selected sterilized women aged 25-44 in the Montreal area in 1985 provided data on their degree of satisfaction with their decisions. The response rate of 67.5% exceeded the expected 60% and the women were similar in characteristics to those of other samples of sterilized women. Some bias may however have been introduced if there were systematic differences in the women not responding. 2 questions were asked to provide estimates of women regretting the sterilization because they would have liked another child. The women were asked if they subsequently regretted their sterilization because they might have wanted another child. Those answering affirmatively were asked if they thought they would actually have attempted pregnancy. A positive answer to the 2nd question was used as the indicator of regret. The results indicated that physicians' estimates of regret are seriously underestimated. 3.9% of the sample said they had discussed the possibility of a reversal with their physicians, but a much higher 21.2% said they had felt regret without openly expressing it to their physician. 12.7% said they would have attempted a later pregnancy and 4.1% said they might have done so. The fundamental variable was age at sterilization. 35.9% of the 167 women aged 20-29 at ligation, 20.5% of the 222 aged 30-34, and 17.9% of the 106 aged 35 or older stated they had at some time regretted their sterilization. 8.4% of those 20-29 at ligation, 8.6% of those 30-34, and 9.4% of those over 35 said they would have tried to have another child. 70% of those who would have wanted

  19. Confinement-induced Molecular Templating and Controlled Ligation

    NASA Astrophysics Data System (ADS)

    Berard, Daniel; Shayegan, Marjan; Michaud, François; Henkin, Gil; Scott, Shane; Leith, Jason; Leslie, Sabrina; Leslie Lab Team

    Loading and manipulating long DNA molecules within sub-50 nm cross-section nanostructures for genomic and biochemical analyses, while retaining their structural integrity, present key technological challenges to the biotechnology sector, such as device clogging and molecular breakage. We overcome these challenges by using Convex Lens-induced Confinement (CLiC) technology to gently load DNA into nanogrooves from above. Here, we demonstrate single-fluorophore visualization of custom DNA barcodes as well as efficient top-loading of DNA into sub-50 nm nanogrooves of variable topographies. We study confinement-enhanced self-ligation of polymers loaded in circular nanogrooves. Further, we use concentric, circular nanogrooves to eliminate confinement gradient-induced drift of stretched DNA.

  20. Sensitive detection of aggregated prion protein via proximity ligation.

    PubMed

    Hammond, Maria; Wik, Lotta; Deslys, Jean-Philippe; Comoy, Emmanuel; Linné, Tommy; Landegren, Ulf; Kamali-Moghaddam, Masood

    2014-01-01

    The DNA assisted solid-phase proximity ligation assay (SP-PLA) provides a unique opportunity to specifically detect prion protein (PrP) aggregates by investigating the collocation of 3 or more copies of the specific protein. We have developed an SP-PLA that can detect PrP aggregates in brain homogenates from infected hamsters even after a 10(7)-fold dilution. In contrast, brain homogenate from uninfected animals did not generate a detectable signal at 100-fold higher concentration. Using either of the 2 monoclonal anti-PrP antibodies, 3F4 and 6H4, we successfully detected low concentrations of aggregated PrP. The presented results provide a proof of concept that this method might be an interesting tool in the development of diagnostic approaches of prion diseases.

  1. In vivo multiphoton imaging of bile duct ligation

    NASA Astrophysics Data System (ADS)

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

    2008-02-01

    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. Seamless Ligation Cloning Extract (SLiCE) cloning method.

    PubMed

    Zhang, Yongwei; Werling, Uwe; Edelmann, Winfried

    2014-01-01

    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.

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

    PubMed Central

    Hultman, Jenni; Ritari, Jarmo; Romantschuk, Martin; Paulin, Lars; Auvinen, Petri

    2008-01-01

    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. PMID:19116002

  4. Intraoperative ligation of residual haemorrhoids after stapled mucosectomy.

    PubMed

    Garg, P

    2009-03-01

    High recurrence rates are being reported with stapled mucosectomy (SM) in patients with high-grade haemorrhoids. A modification was at--tempted in which SM was followed by ligation and cutting of residual prolapsing haemorrhoids, and the procedure was compared with standard SM. The study included 45 patients with high-grade haemorrhoids (grades 3 and 4), who underwent SM. The patients were divided into an SM(std) group (SM by the standard procedure) and an SM(mod) group (SM by the modified procedure). There were 21 patients in the SM(std) group and 19 patients in the SM(mod) group. Five patients were lost to follow-up. The mean age, hospital stay, number of painful days during the postoperative period and the number of days before resumption of normal work were not significantly different between the groups (p>0.05). Recurrence rates were significantly lower in the SM(mod) group (2/19, 10.5%) than in the SM(std) group (14/21, 66.7%; p=0.0004). The percentage of patients highly satisfied (score -1) with the procedure was significantly higher in the SM(mod) group (73.7%, 14/19) than in the SM(std) group (33.3%, 7/21; p=0.014). Patients with high-grade haemorrhoids in whom a modified stapled mucosectomy (ligating and cutting the residual haemorrhoids on the operating table after the procedure) was performed had a significantly lower recurrence rate and better satisfaction rate than patients in whom standard stapled mucosectomy was performed. Long-term studies in a larger group of patients are needed to substantiate these results.

  5. Association of Endoscopic Esophageal Variceal Ligation with Duodenal Ulcer.

    PubMed

    Zhuang, Ze-Hao; Lin, Ai-Fang; Tang, Du-Peng; Wei, Jing-Jing; Liu, Zheng-Ji; Xin, Xiao-Mei; Pan, Yu-Feng

    2016-04-01

    To determine the frequency of duodenal ulcer (DU), as well as other clinical characteristics occurring after endoscopic variceal ligation (EVL) of the esophagus. Descriptive study. The First Affiliated Hospital of Fujian Medical University, Fuzhou, China, from April 2012 to April 2013. A total of 47 patients with esophageal varices (EVr) who had also undergone EVL and gastroscopic follow-up within 3 months of the procedure was retrospectively analyzed. The status of Helicobacter pylori(Hp) infection, Child-Pugh classification, and the grades of portal hypertensive gastropathy (PHG) were collected. Sixty EVr patients without EVL treatment, but with clinical data available, served as the control group. The frequency of DU in the EVL group (29.8%, 14/47) was higher than the control group (6.7%, 4/60) (p=0.02). Hp infection rate in EVLgroup was 19.15% (9/47), while in control group was 21.67% (13/60) (p=0.813). Hp positive rate (12.5%, 1/8) in patients exhibited new DUs after EVL was comparable to the patients without DU in the EVL group (12.1%, 4/33) (p=1.00). Patients with DU after EVL received 18.79 &plusmn;8.48 of ligating bands, while in those who did not exhibit DUs received 13.85 &plusmn;6.47 (z = -2.042, p = 0.041). Logistic regression analysis showed that the occurrence of DU was not associated with age, gender, Child-Pugh classification, or the grade of PHG (p &gt; 0.05). Esophageal EVL is associated with a higher frequency of developing DU, which is related to a larger number of applied bands but is not correlated with Hp infection status or other variables.

  6. High rate of right ventricular infarction after ligation of mid left anterior descending artery in rats.

    PubMed

    Samsamshariat, Seyed Ahmad; Movahed, Mohammad-Reza

    2005-01-01

    The left anterior descending artery (LAD) supplies the left ventricle in humans. LAD ligation has been commonly used in rats to induce left ventricular (LV) infarction for research purposes. However, the myocardial supply territories of LAD are not well established in rats. We measured the infarction zone in rats after ligation of the mid-LAD. Twenty-four male Sprague-Dawley rats weighing 300-350 g were selected for LAD ligation for the induction of ischemic cardiomyopathy. The surgery was performed under full anesthesia. Left-sided thoracotomy was performed through cuts in the fifth and sixth ribs. Ligation of the LAD was performed 1 to 2 mm distal to a line between the left border of the pulmonary conus and the right border of the left atrial appendage. LAD was ligated after the first diagonal and septal branches. After 24 h, the hearts were removed and stained with Tetrazolium Tetrachloride (TTC) for the detection of infracted areas. Ligation of LAD induces 85% infarction of the right anterior free wall and anterior right ventricular septum and induces 100% infarction of the anterior free wall of the left ventricle and anterior septum. Infarction after LAD ligation extends all the way to the distal of the ligation site down to the apex of the heart. Mid-LAD ligation after the first septal and diagonal branches causes substantial right ventricular infarction in addition to LV infarct in rats. Therefore, the hemodynamic effect of right ventricle infarct should be considered in research involving LAD ligation in rats.

  7. Noise figure of hybrid optical parametric amplifiers.

    PubMed

    Marhic, Michel E

    2012-12-17

    Following a fiber optical parametric amplifier, used as a wavelength converter or in the phase-sensitive mode, by a phase-insensitive amplifier (PIA) can significantly reduce four-wave mixing between signals in broadband systems. We derive the quantum mechanical noise figures (NF) for these two hybrid configurations, and show that adding the PIA only leads to a moderate increase in NF.

  8. DESIGN OF A MOLECULAR AMPLIFIER GROUP.

    DTIC Science & Technology

    would be capable of field operation. The Molecular Amplifier Group consists of a traveling -wave amplifier and sufficient support equipment to provide...Ferrite disks of yttrium iron garnet are incorporated in the traveling -wave maser structure to provide sufficient reverse loss for short-circuit

  9. Amplifiers and the origin of animal signals

    PubMed Central

    Johnstone, Rufus A.

    2016-01-01

    In 1989, Hasson introduced the concept of an ‘amplifier’ within animal communication. This display reduces errors in the assessment of traits for which there is direct selection and renders differences in quality among animals more obvious. Amplifiers can evolve to fixation via the benefit they confer on high-quality animals. However, they also impose a cost on low-quality animals by revealing their lower quality, potentially leading these to refrain from amplifying. Hence, it was suggested that, if the level of amplification correlates with quality, direct choice for the amplifying display might emerge. Using the framework of signal detection theory, this article shows that, if the use of an amplifier is observable, direct choice for the amplifying display can indeed evolve. Consequently, low-quality animals may choose to amplify to some extent as well, even though this reveals their lower quality. In effect, the amplifier evolves to become a signal in its own right. We show that, as amplifiers can evolve without direct female choice and are likely to become correlated with male quality, selection for quality-dependent amplification provides a simple explanation for the origin of reliable signals in the absence of pre-existing preferences.

  10. A multicarrier feed-forward amplifier design

    NASA Astrophysics Data System (ADS)

    Myer, Daniel P.

    1994-10-01

    Cellular base stations employ feed-forward amplifiers to maintain low levels of intermodulation distortion. The relative level of distortion depends on the characteristics of the signal (stimulus) as much as the design of the amplifier itself. Careful attention to details in both of these areas is essential for a successful feed-forward design.

  11. Method for reducing snap in magnetic amplifiers

    NASA Technical Reports Server (NTRS)

    Fischer, R. L. E.; Word, J. L.

    1968-01-01

    Method of reducing snap in magnetic amplifiers uses a degenerative feedback circuit consisting of a resistor and a separate winding on a magnetic core. The feedback circuit extends amplifier range by allowing it to be used at lower values of output current.

  12. Fiber networks amplify active stress

    NASA Astrophysics Data System (ADS)

    Lenz, Martin; Ronceray, Pierre; Broedersz, Chase

    Large-scale force generation is essential for biological functions such as cell motility, embryonic development, and muscle contraction. In these processes, forces generated at the molecular level by motor proteins are transmitted by disordered fiber networks, resulting in large-scale active stresses. While fiber networks are well characterized macroscopically, this stress generation by microscopic active units is not well understood. I will present a comprehensive theoretical study of force transmission in these networks. I will show that the linear, small-force response of the networks is remarkably simple, as the macroscopic active stress depends only on the geometry of the force-exerting unit. In contrast, as non-linear buckling occurs around these units, local active forces are rectified towards isotropic contraction and strongly amplified. This stress amplification is reinforced by the networks' disordered nature, but saturates for high densities of active units. I will show that our predictions are quantitatively consistent with experiments on reconstituted tissues and actomyosin networks, and that they shed light on the role of the network microstructure in shaping active stresses in cells and tissue.

  13. Ultrafast disk lasers and amplifiers

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    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.

  14. Multi-pass light amplifier

    NASA Technical Reports Server (NTRS)

    Plaessmann, Henry (Inventor); Grossman, William M. (Inventor)

    1997-01-01

    A multiple-pass laser amplifier that uses optical focusing between subsequent passes through a single gain medium so that a reproducibly stable beam size is achieved within the gain region. A confocal resonator or White Cell resonator is provided, including two or three curvilinearly shaped mirrors facing each other along a resonator axis and an optical gain medium positioned on the resonator axis between the mirrors (confocal resonator) or adjacent to one of the mirrors (White Cell). In a first embodiment, two mirrors, which may include adjacent lenses, are configured so that a light beam passing through the gain medium and incident on the first mirror is reflected by that mirror toward the second mirror in a direction approximately parallel to the resonator axis. A light beam translator, such as an optical flat of transparent material, is positioned to translate this light beam by a controllable amount toward or away from the resonator axis for each pass of the light beam through the translator. The optical gain medium may be solid-state, liquid or gaseous medium and may be pumped longitudinally or transversely. In a second embodiment, first and second mirrors face a third mirror in a White Cell configuration, and the optical gain medium is positioned at or adjacent to one of the mirrors. Defocusing means and optical gain medium cooling means are optionally provided with either embodiment, to controllably defocus the light beam, to cool the optical gain medium and to suppress thermal lensing in the gain medium.

  15. Post pulse shutter for laser amplifier

    DOEpatents

    Bradley, Laird P. [Livermore, CA; Carder, Bruce M. [Antioch, CA; Gagnon, William L. [Berkeley, CA

    1981-03-17

    Apparatus and method for quickly closing off the return path for an amplified laser pulse at the output of an amplifier so as to prevent damage to amplifiers and other optical components appearing earlier in the chain by the return of an amplified pulse. The apparatus consists of a fast retropulse or post pulse shutter to suppress target reflection and/or beam return. This is accomplished by either quickly placing a solid across the light transmitting aperture of a component in the chain, such as a spatial filter pinhole, or generating and directing a plasma with sufficiently high density across the aperture, so as to, in effect, close the aperture to the returning amplified energy pulse.

  16. Post pulse shutter for laser amplifier

    DOEpatents

    Bradley, L.P.; Carder, B.M.; Gagnon, W.L.

    1981-03-17

    Disclosed are an apparatus and method for quickly closing off the return path for an amplified laser pulse at the output of an amplifier so as to prevent damage to amplifiers and other optical components appearing earlier in the chain by the return of an amplified pulse. The apparatus consists of a fast retropulse or post pulse shutter to suppress target reflection and/or beam return. This is accomplished by either quickly placing a solid across the light transmitting aperture of a component in the chain, such as a spatial filter pinhole, or generating and directing a plasma with sufficiently high density across the aperture, so as to, in effect, close the aperture to the returning amplified energy pulse. 13 figs.

  17. Dual-range linearized transimpedance amplifier system

    DOEpatents

    Wessendorf, Kurt O.

    2010-11-02

    A transimpedance amplifier system is disclosed which simultaneously generates a low-gain output signal and a high-gain output signal from an input current signal using a single transimpedance amplifier having two different feedback loops with different amplification factors to generate two different output voltage signals. One of the feedback loops includes a resistor, and the other feedback loop includes another resistor in series with one or more diodes. The transimpedance amplifier system includes a signal linearizer to linearize one or both of the low- and high-gain output signals by scaling and adding the two output voltage signals from the transimpedance amplifier. The signal linearizer can be formed either as an analog device using one or two summing amplifiers, or alternately can be formed as a digital device using two analog-to-digital converters and a digital signal processor (e.g. a microprocessor or a computer).

  18. Bandwidth tunable amplifier for recording biopotential signals.

    PubMed

    Hwang, Sungkil; Aninakwa, Kofi; Sonkusale, Sameer

    2010-01-01

    This paper presents a low noise, low power, bandwidth tunable amplifier for bio-potential signal recording applications. By employing depletion-mode pMOS transistor in diode configuration as a tunable sub pA current source to adjust the resistivity of MOS-Bipolar pseudo-resistor, the bandwidth is adjusted without any need for a separate band-pass filter stage. For high CMRR, PSRR and dynamic range, a fully differential structure is used in the design of the amplifier. The amplifier achieves a midband gain of 39.8dB with a tunable high-pass cutoff frequency ranging from 0.1Hz to 300Hz. The amplifier is fabricated in 0.18εm CMOS process and occupies 0.14mm(2) of chip area. A three electrode ECG measurement is performed using the proposed amplifier to show its feasibility for low power, compact wearable ECG monitoring application.

  19. Calculations of superconducting parametric amplifiers performances

    NASA Astrophysics Data System (ADS)

    Goto, T.; Takeda, M.; Saito, S.; Shimakage, H.

    2017-07-01

    A superconducting parametric amplifier is an electromagnetic wave amplifier with high-quality characteristics such as a wide bandwidth, an extremely low noise, and a high dynamic range. In this paper, we report on the estimations of a YBCO superconducting parametric amplifier characteristic. The YBCO thin films were deposited on an MgO substrate by a pulsed laser deposition method. Based on the measured YBCO thin film parameters, theoretical calculations were implemented for evaluations of kinetic inductance nonlinearities and parametric gains. The nonlinearity of the YBCO thin film was estimated to be stronger than a single crystal NbTiN thin film. It is indicated that the YBCO parametric amplifier has a potential to be realized the amplifier with the high parametric gain. It is also expected that it could be operated in the range of the high frequency band, at the high temperature, and low applied current.

  20. Design and performance of the beamlet amplifiers

    SciTech Connect

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

    1996-06-01

    In future laser systems, such as the National Ignition Facility (NIF), multi-segment amplifiers (MSAs) will be used to amplify the laser beam to the required levels. As a prototype of such a laser architecture, the authors have designed, built, and tested flash-lamp-pumped, Nd:Glass, Brewster-angle slab MSAs for the Beamlet project. In this article, they review the fundamentals of Nd:Glass amplifiers, describe the MSA geometry, discuss parameters that are important in amplifier design, and present our results on the characterization of the Beamlet MSAs. In particular, gain and beam steering measurements show that the Beamlet amplifiers meet all optical performance specifications and perform close to model predictions.

  1. Direct solar-pumped iodine laser amplifier

    NASA Technical Reports Server (NTRS)

    Han, K. S.

    1986-01-01

    During this period the parametric studies of the iodine laser oscillator pumped by a Vortek simulator were carried out before amplifier studies. The amplifier studies are postponed to the extended period after completing the parametric studies. In addition, the kinetic modeling of a solar-pumped iodine laser amplifier, and the experimental work for a solar pumped dye laser amplifier are in progress. This report contains three parts: (1) a 10 W CW iodine laser pumped by a Vortek solar simulator; (2) kinetic modeling to predict the time to lasing threshold, lasing time, and energy output of solar-pumped iodine laser; and (3) the study of the dye laser amplifier pumped by a Tamarack solar simulator.

  2. Rapid identification and characterization of Penicillium marneffei using multiplex ligation-dependent probe amplification (MLPA) in paraffin-embedded tissue samples.

    PubMed

    Zhang, Jun-Min; Sun, Jiu-Feng; Feng, Pei-Ying; Li, Xi-Qing; Lu, Chang-Ming; Lu, Sha; Cai, Wen-Ying; Xi, Li-Yan; de Hoog, G S

    2011-04-01

    Penicillium marneffei infection is a deadly disease and early diagnosis leads to prompt and appropriate antifungal therapy. To develop a sensitive method to diagnose P. marneffei infection, a multiplex ligation-dependent probe amplification (MLPA) assay was adapted. This method can rapidly and specifically detect P. marneffei DNA in cultured cells and paraffin-embedded tissue samples. Three pairs of probes were designed for amplifying the internally (intergenic) transcribed spacer (ITS) region of P. marneffei rRNA using a systematic phylogenetic analysis. These three probe sets produced three amplicons of 198, 166, and 152 bp, respectively, specific for P. marneffei. In contrast, there was only one 198 bp amplicon produced for Talaromyces stipitatus, and one 152 bp amplicon for P. funiculosum, T. intermedius and T. derxii. The probes did not amplify any other reference strains. An array of 40 P. marneffei strains isolated from human patients, bamboo rat, and the local environment was tested by using MLPA, and all were positively identified. Most importantly, P. marneffei in paraffin-embedded tissue specimens from infected human patients was positively amplified by MLPA. The sensitivity and specificity of the MLPA assay could be a useful tool for prompt diagnosis, pathogen characterization, and epidemiological studies of fungal infections.

  3. Coarctation of the Aorta as a Complication of Surgical Ligation of Patent Ductus Arteriosus in a Premature Infant

    PubMed Central

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

    2017-01-01

    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

  4. Digital quantification of rolling circle amplified single DNA molecules in a resistive pulse sensing nanopore.

    PubMed

    Kühnemund, M; Nilsson, M

    2015-05-15

    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.

  5. Recursive directional ligation by plasmid reconstruction allows rapid and seamless cloning of oligomeric genes.

    PubMed

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

    2010-04-12

    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.

  6. Left ventricular efficiency after ligation of patent ductus arteriosus for premature infants.

    PubMed

    Nagata, Hazumu; Ihara, Kenji; Yamamura, Kenichiro; Tanoue, Yoshihisa; Shiokawa, Yuichi; Tominaga, Ryuji; Hara, Toshiro

    2013-12-01

    The purpose of this study was to evaluate the hemodynamic changes in left ventricular function before and after patent ductus arteriosus ligation in premature infants with regard to the energetic efficiency of left ventricular pumping. Thirty-five premature infants who underwent patent ductus arteriosus ligation were enrolled in this study. Left ventricular efficiency was evaluated at 4 points: within 24 hours before patent ductus arteriosus ligation, within 24 hours after patent ductus arteriosus ligation, between postoperative days 2 and 4, and on postoperative day 7. The indices of contractility (end-systolic elastance) and afterload (effective arterial elastance) were approximated on the basis of the systemic blood pressure and systolic or diastolic left ventricular volume. The ratio of stroke work and pressure-volume area, representing the ventricular efficiency, was estimated using the following theoretic formula: the ratio of stroke work and pressure-volume area = 1/(1 + 0.5 ventriculoarterial coupling). Left ventricular efficiency was transiently deteriorated within 24 hours after patent ductus arteriosus ligation because of the marked increase of the afterload and the slight increase of contraction, and then recovered to preoperation levels by 2 to 4 days after patent ductus arteriosus ligation. Analysis of indices representing the afterload, contractility, and energetic efficiency of the left ventricle may provide practical information for the management of premature infants during the postoperative period after patent ductus arteriosus ligation. Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

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

    PubMed Central

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

    2014-01-01

    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 Mn2+, but was strongly inhibited by concentrations of NaCl >100 mM. Abortive adenylylation was suppressed at low ATP concentrations (<100 µM) and pH >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. PMID:24203707

  8. Kinetic and mechanistic analysis of nonenzymatic, template-directed oligoribonucleotide ligation

    NASA Technical Reports Server (NTRS)

    Rohatgi, R.; Bartel, D. P.; Szostak, J. W.

    1996-01-01

    The role of divalent cations in the mechanism of pyrophosphate-activated, template-directed oligoribonucleotide ligation has been investigated. The dependence of the reaction rate on Mg2+ concentration suggests a kinetic scheme in which a Mg2+ ion must bind before ligation can proceed. Mn2+, Ca2+, Sr2+, and Ba2+ can also catalyze the reaction. Although Pb2+ and Zn2+ do not catalyze the reaction in the absence of other divalent ions, they significantly modulate the reaction rate when added in the presence of Mg2+, with Pb2+ stimulating the reaction (up to 65-fold) and Zn2+ inhibiting the reaction. The logarithm of the ligation rate increases linearly, with slope of 0.95, as a function of pH, indicating that the reaction involves a single critical deprotonation step. The ligation rates observed with the different divalent metal ion catalysts (Mn2+ > Mg2+ > Ca2+ > Sr2+ = Ba2+) vary inversely with the pKa values of their bound water molecules. The pH profile and these relative ligation rates suggest a mechanism in which a metal-bound hydroxide ion located near the ligation junction promotes catalysis, most likely by deprotonation of the hydroxl nucleophile. The effects of changing either the leaving group or the attacking hydroxyl, together with the large delta S(++) value for oligonucleotide ligation (about -20 eu), are consistent with an associative transition state.

  9. A prospective randomised study of local anaesthetic injection after multiple rubber band ligation of haemorrhoids.

    PubMed

    Gokalp, Avni; Baskonus, Ilyas; Maralcan, Gokturk

    2003-01-01

    One hundred and forty-two patients with second and third degree internal haemorrhoids were randomised to rubber band ligation only (n = 72) or rubber band ligation + local anaesthetic injection (n = 70). Pain was assessed by the patients at intervals of 6 hours and 1, 2, 3 and 4 days after banding. Other symptoms, complications, analgesic requirements and patient satisfaction were also recorded for 10 days following the treatment. There was a significant reduction in pain at 60 minutes and 6 hours after the procedure in the rubber band ligation plus local anaesthetic injection patients compared with the rubber band ligation only group (P < 0.05), but there was no reduction in pain when local anaesthetic was used compared with rubber band ligation only on days 1, 2, 3 and 4 days after ligation. On day 10 after banding, there was no difference between the two groups with respect to symptoms such as nausea, feeling of heaviness and/or tenesmus, fainting; complications, analgesic consumption or overall patient satisfaction. Bupivacaine injection after multiple rubber band ligation may be useful in reducing pain during the first 6 hours of the postbanding period.

  10. Is tubal ligation a risk factor for low bone density and increased risk of fracture?

    PubMed

    Fox, K M; Cummings, S R

    1995-01-01

    Osteoporosis is a major women's health problem, because it is responsible for about 1.3 million fractures in the United States each year. Estrogen deficiency is a major risk factor in the pathogenesis of osteoporosis. Recent evidence has indicated that tubal ligation may cause menstrual dysfunction and estrogen deficiency. This study examined the association between tubal ligation and bone mass in a group of elderly postmenopausal women. Subjects were 2215 white women > or = 65 years old participating in the Baltimore center of the Study of Osteoporotic Fractures. Bone mineral density of the proximal and distal radius and the calcaneus was measured by single photon absorptiometry. Multiple regression analysis was performed to determine whether tubal ligation had an independent effect on bone density. The effect of tubal ligation on the risk of hip and osteoporotic fractures was estimated by Cox proportional hazards model. Women who reported a tubal ligation had lower, although not statistically significant, bone density of the radius and calcaneus. The relative risk of hip (1.05, 95% confidence limit 0.84 to 1.32) and osteoporotic fractures (1.01, 0.80 to 1.29) was not significantly increased in women with tubal ligation. We conclude that elderly women who had a tubal ligation have small changes in bone density that are not of sufficient magnitude to increase their risk of osteoporotic fractures.

  11. Protein synthesis by native chemical ligation: Expanded scope by using straightforward methodology

    PubMed Central

    Hackeng, Tilman M.; Griffin, John H.; Dawson, Philip E.

    1999-01-01

    The total chemical synthesis of proteins has great potential for increasing our understanding of the molecular basis of protein function. The introduction of native chemical ligation techniques to join unprotected peptides next to a cysteine residue has greatly facilitated the synthesis of proteins of moderate size. Here, we describe a straightforward methodology that has enabled us to rapidly analyze the compatibility of the native chemical ligation strategy for X–Cys ligation sites, where X is any of the 20 naturally occurring amino acids. The simplified methodology avoids the necessity of specific amino acid thioester linkers or alkylation of C-terminal thioacid peptides. Experiments using matrix-assisted laser-desorption ionization MS analysis of combinatorial ligations of LYRAX-C-terminal thioester peptides to the peptide CRANK show that all 20 amino acids are suitable for ligation, with Val, Ile, and Pro representing less favorable choices because of slow ligation rates. To illustrate the method’s utility, two 124-aa proteins were manually synthesized by using a three-step, four-piece ligation to yield a fully active human secretory phospholipase A2 and a catalytically inactive analog. The combination of flexibility in design with general access because of simplified methodology broadens the applicability and versatility of chemical protein synthesis. PMID:10468563

  12. Kinetic and mechanistic analysis of nonenzymatic, template-directed oligoribonucleotide ligation

    NASA Technical Reports Server (NTRS)

    Rohatgi, R.; Bartel, D. P.; Szostak, J. W.

    1996-01-01

    The role of divalent cations in the mechanism of pyrophosphate-activated, template-directed oligoribonucleotide ligation has been investigated. The dependence of the reaction rate on Mg2+ concentration suggests a kinetic scheme in which a Mg2+ ion must bind before ligation can proceed. Mn2+, Ca2+, Sr2+, and Ba2+ can also catalyze the reaction. Although Pb2+ and Zn2+ do not catalyze the reaction in the absence of other divalent ions, they significantly modulate the reaction rate when added in the presence of Mg2+, with Pb2+ stimulating the reaction (up to 65-fold) and Zn2+ inhibiting the reaction. The logarithm of the ligation rate increases linearly, with slope of 0.95, as a function of pH, indicating that the reaction involves a single critical deprotonation step. The ligation rates observed with the different divalent metal ion catalysts (Mn2+ > Mg2+ > Ca2+ > Sr2+ = Ba2+) vary inversely with the pKa values of their bound water molecules. The pH profile and these relative ligation rates suggest a mechanism in which a metal-bound hydroxide ion located near the ligation junction promotes catalysis, most likely by deprotonation of the hydroxl nucleophile. The effects of changing either the leaving group or the attacking hydroxyl, together with the large delta S(++) value for oligonucleotide ligation (about -20 eu), are consistent with an associative transition state.

  13. Efficient DNA ligation in DNA-RNA hybrid helices by Chlorella virus DNA ligase.

    PubMed

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

    2014-02-01

    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) < 1 nM at 25 °C under conditions where T4 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 (<100 µM) and pH >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.

  14. Progress on diamond amplified photo-cathode

    SciTech Connect

    Wang, E.; Ben-Zvi, I.; Burrill, A.; Kewisch, J.; Chang, X.; Rao, T.; Smedley, J.; Wu, Q.; Muller, E.; Xin, T.

    2011-03-28

    Two years ago, we obtained an emission gain of 40 from the Diamond Amplifier Cathode (DAC) in our test system. In our current systematic study of hydrogenation, the highest gain we registered in emission scanning was 178. We proved that our treatments for improving the diamond amplifiers are reproducible. Upcoming tests planned include testing DAC in a RF cavity. Already, we have designed a system for these tests using our 112 MHz superconducting cavity, wherein we will measure DAC parameters, such as the limit, if any, on emission current density, the bunch charge, and the bunch length. The diamond-amplified photocathode, that promises to support a high average current, low emittance, and a highly stable electron beam with a long lifetime, is under development for an electron source. The diamond, functioning as a secondary emitter amplifies the primary current, with a few KeV energy, that comes from the traditional cathode. Earlier, our group recorded a maximum gain of 40 in the secondary electron emission from a diamond amplifier. In this article, we detail our optimization of the hydrogenation process for a diamond amplifier that resulted in a stable emission gain of 140. We proved that these characteristics are reproducible. We now are designing a system to test the diamond amplifier cathode using an 112MHz SRF gun to measure the limits of the emission current's density, and on the bunch charge and bunch length.

  15. Differences in bleeding behavior after endoscopic band ligation: a retrospective analysis

    PubMed Central

    2010-01-01

    Background Endoscopic band ligation (EBL) is generally accepted as the treatment of choice for bleeding from esophageal varices. It is also used for secondary prophylaxis of esophageal variceal hemorrhage. However, there is no data or guidelines concerning endoscopic control of ligation ulcers. We conducted a retrospective study of EBL procedures analyzing bleeding complications after EBL. Methods We retrospectively analyzed data from patients who underwent EBL. We analyzed several data points, including indication for the procedure, bleeding events and the time interval between EBL and bleeding. Results 255 patients and 387 ligation sessions were included in the analysis. We observed an overall bleeding rate after EBL of 7.8%. Bleeding events after elective treatment (3.9%) were significantly lower than those after treatment for acute variceal hemorrhage (12.1%). The number of bleeding events from ligation ulcers and variceal rebleeding was 14 and 15, respectively. The bleeding rate from the ligation site in the group who underwent emergency ligation was 7.1% and 0.5% in the group who underwent elective ligation. Incidence of variceal rebleeding did not vary significantly. Seventy-five percent of all bleeding episodes after elective treatment occurred within four days after EBL. 20/22 of bleeding events after emergency ligation occured within 11 days after treatment. Elective EBL has a lower risk of bleeding from treatment-induced ulceration than emergency ligation. Conclusions Patients who underwent EBL for treatment of acute variceal bleeding should be kept under medical surveillance for 11 days. After elective EBL, it may be reasonable to restrict the period of surveillance to four days or even perform the procedure in an out-patient setting. PMID:20074379

  16. Differences in bleeding behavior after endoscopic band ligation: a retrospective analysis.

    PubMed

    Petrasch, Florian; Grothaus, Johannes; Mössner, Joachim; Schiefke, Ingolf; Hoffmeister, Albrecht

    2010-01-15

    Endoscopic band ligation (EBL) is generally accepted as the treatment of choice for bleeding from esophageal varices. It is also used for secondary prophylaxis of esophageal variceal hemorrhage. However, there is no data or guidelines concerning endoscopic control of ligation ulcers. We conducted a retrospective study of EBL procedures analyzing bleeding complications after EBL. We retrospectively analyzed data from patients who underwent EBL. We analyzed several data points, including indication for the procedure, bleeding events and the time interval between EBL and bleeding. 255 patients and 387 ligation sessions were included in the analysis. We observed an overall bleeding rate after EBL of 7.8%. Bleeding events after elective treatment (3.9%) were significantly lower than those after treatment for acute variceal hemorrhage (12.1%). The number of bleeding events from ligation ulcers and variceal rebleeding was 14 and 15, respectively. The bleeding rate from the ligation site in the group who underwent emergency ligation was 7.1% and 0.5% in the group who underwent elective ligation. Incidence of variceal rebleeding did not vary significantly. Seventy-five percent of all bleeding episodes after elective treatment occurred within four days after EBL. 20/22 of bleeding events after emergency ligation occurred within 11 days after treatment. Elective EBL has a lower risk of bleeding from treatment-induced ulceration than emergency ligation. Patients who underwent EBL for treatment of acute variceal bleeding should be kept under medical surveillance for 11 days. After elective EBL, it may be reasonable to restrict the period of surveillance to four days or even perform the procedure in an out-patient setting.

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

    SciTech Connect

    Sakai, Hiroshi; Tagawa, Yoh-ichi; Tamai, Miho; Motoyama, Hiroaki; Ogawa, Shinichiro; Soeda, Junpei; Nakata, Takenari; Miyagawa, Shinichi

    2010-12-17

    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.

  18. The ligation of the intersphincteric fistula tract procedure for anal fistula: a mixed bag of results.

    PubMed

    Sirany, Anne-Marie E; Nygaard, Rachel M; Morken, Jeffrey J

    2015-06-01

    The ligation of the intersphincteric fistula tract procedure, a sphincter-preserving technique, aims to obtain complete, durable healing, while preserving fecal continence in the treatment of transsphincteric anal fistulas. This was a systematic review to evaluate the outcomes of the originally described (classic) ligation of the intersphincteric fistula tract procedure and the identified technical variations of the procedure. PubMed, Web of Science, and the archive of Diseases of the Colon & Rectum were searched with the terms "ligation of intersphincteric fistula" and "ligation of intersphincteric fistula tract." Original, English-language studies reporting the primary healing rate for each technical variation of the ligation of the intersphincteric fistula tract procedure were included. Studies were excluded when the technique used was unclear or when primary healing rate was reported in a pooled manner including outcomes from multiple technical variations of the ligation of the intersphincteric fistula tract procedure. Outcomes associated with all of the technical variations of the ligation of the intersphincteric fistula tract procedure were investigated. The main outcome measured was primary healing rate. Secondary outcome measures included time to healing, changes in continence, and risk factors for failure. In all, 26 studies met criteria for review, including 1 randomized controlled trial and 25 cohort/case series. Seven technical variations of the ligation of the intersphincteric fistula tract procedure were identified and classified according to the surgical technique. Primary healing rates ranged from 47% to 95%. The levels of evidence available in the published works are relatively low, as indicated by the Oxford Center for Evidence-Based Medicine evidence levels. The ligation of the intersphincteric fistula tract procedure is a promising treatment option for transsphincteric fistulas, with reasonable success rates and minimal impact on continence. The

  19. Quasi-optical constrained lens amplifiers

    NASA Astrophysics Data System (ADS)

    Schoenberg, Jon S.

    1995-09-01

    A major goal in the field of quasi-optics is to increase the power available from solid state sources by combining the power of individual devices in free space, as demonstrated with grid oscillators and grid amplifiers. Grid amplifiers and most amplifier arrays require a plane wave feed, provided by a far field source or at the beam waist of a dielectric lens pair. These feed approaches add considerable loss and size, which is usually greater than the quasi-optical amplifier gain. In addition, grid amplifiers require external polarizers for stability, further increasing size and complexity. This thesis describes using constrained lens theory in the design of quasi optical amplifier arrays with a focal point feed, improving the power coupling between the feed and the amplifier for increased gain. Feed and aperture arrays of elements, input/output isolation and stability, amplifier circuitry, delay lines and bias distribution are all contained on a single planar substrate, making monolithic circuit integration possible. Measured results of X band transmission lenses and a low noise receive lens are presented, including absolute power gain up to 13 dB, noise figure as low as 1.7 dB, beam scanning to +/-30 deg, beam forming and beam switching of multiple sources, and multiple level quasi-optical power combining. The design and performance of millimeter wave power combining amplifier arrays is described, including a Ka Band hybrid array with 1 watt output power, and a V Band 36 element monolithic array with a 5 dB on/off ratio.

  20. A Low-Noise Semiconductor Optical Amplifier

    SciTech Connect

    Ratowsky, R.P.; Dijaili, S.; Kallman, J.S.; Feit, M.D.; Walker, J.

    1999-03-23

    Optical amplifiers are essential devices for optical networks, optical systems, and computer communications. These amplifiers compensate for the inevitable optical loss in long-distance propagation (>50 km) or splitting (>10x). Fiber amplifiers such as the erbium-doped fiber amplifier have revolutionized the fiber-optics industry and are enjoying widespread use. Semiconductor optical amplifiers (SOAs) are an alternative technology that complements the fiber amplifiers in cost and performance. One obstacle to the widespread use of SOAs is the severity of the inevitable noise output resulting from amplified spontaneous emission (ASE). Spectral filtering is often used to reduce ASE noise, but this constrains the source spectrally, and improvement is typically limited to about 10 dB. The extra components also add cost and complexity to the final assembly. The goal of this project was to analyze, design, and take significant steps toward the realization of an innovative, low-noise SOA based on the concept of ''distributed spatial filtering'' (DSF). In DSF, we alternate active SOA segments with passive free-space diffraction regions. Since spontaneous emission radiates equally in all directions, the free-space region lengthens the amplifier for a given length of gain region, narrowing the solid angle into which the spontaneous emission is amplified [1,2]. Our innovation is to use spatial filtering in a differential manner across many segments, thereby enhancing the effect when wave-optical effects are included [3]. The structure quickly and effectively strips the ASE into the higher-order modes, quenching the ASE gain relative to the signal.

  1. Comments to 'Rubber band ligation versus excisional haemorrhoidectomy for haemorrhoids'.

    PubMed

    Brown, S R; Watson, A

    2016-09-01

    To review the efficacy and safety of the two most popular conventional methods of haemorrhoidal treatment, rubber band ligation and excisional haemorrhoidectomy (EH). The original study has now been updated using the same search strategy. We searched MEDLINE, EMBASE, CENTRAL, and CINAHL up to October 2010. Randomised controlled trials comparing rubber band ligation with EH for symptomatic haemorrhoids in adult human patients were included. We extracted data on to a previously designed data extraction sheet. Dichotomous data were presented as relative risk and 95 % confidence intervals, and continuous outcomes as weighted mean difference and 95 % confidence intervals. Three trials (of poor methodological quality) met the inclusion criteria. Complete remission of haemorrhoidal symptom was better with EH (three studies, 202 patients, RR 1.68, 95 % CI 1.00-2.83). There was a significant heterogeneity between the studies (I2 = 90.5 %; P = 0.0001). Similar analysis based on the grading of haemorrhoids revealed the superiority of EH over RBL for grade III haemorrhoids (prolapse that needs manual reduction) (two trials, 116 patients, RR 1.23, CI 1.04-1.45; P = 0.01). However, no significant difference was noticed in grade II haemorrhoids (prolapse that reduces spontaneously on cessation of straining) (one trial, 32 patients, RR 1.07, CI 0.94-1.21; P = 0.32). Fewer patients required re-treatment after EH (three trials, RR 0.20, CI 0.09-0.40; P < 0.00001). Patients undergoing EH were at significantly higher risk of post-operative pain (three trials, fixed effect; 212 patients, RR 1.94, 95 % CI 1.62-2.33, P < 0.00001) and of delayed complications (three trials, 204 patients, RR 6.32, CI 1.15-34.89; P = 0.03). The present systematic review confirms the long-term efficacy of EH, at least for grade III haemorrhoids, compared to the less invasive technique of RBL but at the expense of increased pain, higher complications and more time off work. However, despite

  2. Evaluation of small ligand-protein interaction by ligation reaction with DNA-modified ligand.

    PubMed

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

    2010-01-01

    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.

  3. A modified version of the digestion-ligation cloning method for more efficient molecular cloning.

    PubMed

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

    2014-05-15

    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.

  4. Phase noise in RF and microwave amplifiers.

    PubMed

    Boudot, Rodolphe; Rubiola, Enrico

    2012-12-01

    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

  5. Diode amplifier of modulated optical beam power

    SciTech Connect

    D'yachkov, N V; Bogatov, A P; Gushchik, T I; Drakin, A E

    2014-11-30

    Analytical relations are obtained between characteristics of modulated light at the output and input of an optical diode power amplifier operating in the highly saturated gain regime. It is shown that a diode amplifier may act as an amplitude-to-phase modulation converter with a rather large bandwidth (∼10 GHz). The low sensitivity of the output power of the amplifier to the input beam power and its high energy efficiency allow it to be used as a building block of a high-power multielement laser system with coherent summation of a large number of optical beams. (lasers)

  6. Self-Amplified Optical Pattern Recognizer

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang

    1993-01-01

    Self-amplified optical pattern recognizers developed for use in recognition of patterns, in optical computing, and in optoelectronic neural networks. In recognizer, photorefractive crystal serves as medium in which one holographically records diffraction-grating filter representing pattern with which recognition sought. Apparatus "self-amplified" because signal amplified within filter to many orders of magnitude greater than in prior optical pattern recognizers. Basic principle of operation applicable to many types of correlation filters, including (but not limited to) Vander Lugt matched filters, joint-transform filters, and phase-only filters.

  7. High Efficiency Microwave Power Amplifier (HEMPA) Design

    NASA Technical Reports Server (NTRS)

    Sims, W. Herbert

    2004-01-01

    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.

  8. Quantum coherence effects in a Raman amplifier

    NASA Astrophysics Data System (ADS)

    Ooi, C. H. Raymond; Harun, S. W.; Ahmad, H.

    2011-01-01

    We have studied optical pulse propagation in a Raman fiber amplifier doped with a three-level medium and driven by a control laser pulse. We analyze the spatial-temporal dynamics of pulse propagation for different atomic initial conditions. The propagation of an optical pulse through the amplifier can be sustained by a control laser that induces transparency via quantum coherence, which is useful for extending the distance between optical repeaters. Under certain conditions, amplification is achieved without population inversion. The results could be useful for laser control of optical pulses in amplifiers and waveguides.

  9. Achieving and maintaining cleanliness in NIF amplifiers

    SciTech Connect

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

    1998-07-28

    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.

  10. The 60 GHz solid state power amplifier

    NASA Technical Reports Server (NTRS)

    Mcclymonds, J.

    1991-01-01

    A new amplifier architecture was developed during this contract that is superior to any other solid state approach. The amplifier produced 6 watts with 4 percent efficiency over a 2 GHz band at 61.5 GHz. The unit was 7 x 9 x 3 inches in size, 5.5 pounds in weight, and the conduction cooling through the baseplate is suitable for use in space. The amplifier used high efficiency GaAs IMPATT diodes which were mounted in 1-diode circuits, called modules. Eighteen modules were used in the design, and power combining was accomplished with a proprietary passive component called a combiner plate.

  11. Simultaneous detection of genetically modified organisms by multiplex ligation-dependent genome amplification and capillary gel electrophoresis with laser-induced fluorescence.

    PubMed

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

    2010-07-01

    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.

  12. Efficiency of ligation-mediated PCR and TAIL-PCR methods for isolation of RbcS promoter sequences from green microalgae Ankistrodesmus convolutus.

    PubMed

    Thanh, Tran; Chi, Vu Thi Quynh; Abdullah, Mohd Puad; Omar, Hishamuddin; Napis, Suhaimi

    2012-01-01

    Isolation of promoter sequences from known gene sequences is a tedious task in genome-related research. An efficient method of obtaining the promoter sequences is necessary in order to successfully use targeted promoters for genetic manipulations. Here, efficiency and usefulness of two PCR-based methods, namely: ligation-mediated PCR and thermal asymmetric interlaced (TAIL) PCR, for isolation of promoter sequences of the ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (RbcS) gene from green microalgae Ankistrodesmus convolutus (A. convolutus) were evaluated. The results showed that the amplification efficiency of TAIL-PCR was higher than that of the ligation-mediated PCR method, i.e. the amplified promoter fragments of 1.2 and 0.8 kb in length or promoter sequences of 813 and 606 bp (after eliminating the unreadable sequences). The use of TAIL-PCR described here presents a low cost and efficient strategy for the isolation of promoter sequences of known genes, especially in GC-rich regions, and species with little or no available genome information such as A. convolutus.

  13. Multi-pass light amplifier

    NASA Technical Reports Server (NTRS)

    Plaessmann, Henry (Inventor); Grossman, William M. (Inventor); Olson, Todd E. (Inventor)

    1996-01-01

    A multiple-pass laser amplifier that uses optical focusing between subsequent passes through a single gain medium so that a reproducibly stable beam size is achieved within the gain region. A resonator or a White Cell cavity is provided, including two or more mirrors (planar or curvilinearly shaped) facing each other along a resonator axis and an optical gain medium positioned on a resonator axis between the mirrors or adjacent to one of the mirrors. In a first embodiment, two curvilinear mirrors, which may include adjacent lenses, are configured so that a light beam passing through the gain medium and incident on the first mirror is reflected by that mirror toward the second mirror in a direction approximately parallel to the resonator axis. A light beam translator, such as an optical flat of transparent material, is positioned to translate this light beam by a controllable amount toward or away from the resonator axis for each pass of the light beam through the translator. A second embodiment uses two curvilinear mirrors and one planar mirror, with a gain medium positioned in the optical path between each curvilinear mirror and the planar mirror. A third embodiment uses two curvilinear mirrors and two planar mirrors, with a gain medium positioned adjacent to a planar mirror. A fourth embodiment uses a curvilinear mirror and three planar mirrors, with a gain medium positioned adjacent to a planar mirror. A fourth embodiment uses four planar mirrors and a focusing lens system, with a gain medium positioned between the four mirrors. A fifth embodiment uses first and second planar mirrors, a focusing lens system and a third mirror that may be planar or curvilinear, with a gain medium positioned adjacent to the third mirror. A sixth embodiment uses two planar mirrors and a curvilinear mirror and a fourth mirror that may be planar or curvilinear, with a gain medium positioned adjacent to the fourth mirror. In a seventh embodiment, first and second mirrors face a third

  14. Effect of Ligation Method on Maxillary Arch Force/Moment Systems for a Simulated Lingual Incisor Malalignment

    PubMed Central

    Seru, Surbhi; Romanyk, Dan L; Toogood, Roger W; Carey, Jason P; Major, Paul W

    2014-01-01

    Introduction: The objectives of this study were to determine whether there is a difference in the magnitude of forces and moments produced by elastic ligation when compared to passive ligation, and whether these forces and moments propagate differently along the arch for the two ligation types. A lingual incisor malalignment was used in this study. Methods: The Orthodontic Simulator (OSIM) was used to quantify the three-dimensional forces and moments applied on the teeth given a lingually displaced incisor. A repeated measures MANOVA was performed to statistically analyze the data. Results: The interaction factor illustrated convincing evidence that there is a difference in maximum force and moment values for all outcome variables between ligation types considering all tooth positions along the arch. The mean differences for FX and FY between ligation types were found to be clinically significant, with values for elastic ligation consistently higher than passive ligation. Conclusion: It was found that the maximum forces and moments produced by elastic ligation are greater than those produced by passive ligation and that the magnitude of this difference for the mesiodistal and buccolingual forces is clinically relevant. Additionally, it was determined that elastic ligation causes forces and moments to propagate further along the arch than passive ligation for all outcome variables. PMID:25400715

  15. A Novel Model of Severe Gallstone Pancreatitis: Murine Pancreatic Duct Ligation Results in Systemic Inflammation and Substantial Mortality

    PubMed Central

    Samuel, Isaac; Yuan, Zuobiao; Meyerholz, David K.; Twait, Erik; Williard, Deborah E.; Kempuraj, Duraisamy

    2010-01-01

    Background Suitable experimental models of gallstone pancreatitis with systemic inflammation and mortality are limited. We developed a novel murine model of duct-ligation-induced acute pancreatitis associated with multiorgan dysfunction and severe mortality. Methods Laparotomy was done on C57/BL6 mice followed by pancreatic duct (PD) ligation, bile duct (BD) ligation without PD ligation, or sham operation. Results Only mice with PD ligation developed acute pancreatitis and had 100% mortality. Pulmonary compliance was significantly reduced after PD ligation but not BD ligation. Bronchoalveolar lavage fluid neutrophil count and interleukin-1β concentration, and the plasma creatinine level, were significantly elevated with PD ligation but not BD ligation. Pancreatic nuclear factor κB (p65) and activator protein 1 (c-Jun) were activated within 1 h of PD ligation. Conclusion PD-ligation-induced acute pancreatitis in mice is associated with systemic inflammation, acute lung injury, multiorgan dysfunction and death. The development of this novel model is an exciting and notable advance in the field. PMID:20975317

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

    PubMed

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

    2014-10-16

    To investigate the safety and efficacy of endoscopic band ligation (EBL) for bleeding lesions in the small bowel. This is a retrospective study evaluating EBL in six consecutive patients (three males, three females, 46-86 years of age) treated between May 2009 and February 2014: duodenal vascular ectasia; 1, jejunal 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 formation. Follow-up endoscopies were performed in four patients. 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 a repeat 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. EBL is a safe and effective endoscopic treatment for hemostasis of bleeding lesions in the small bowel.

  17. Acute bile duct ligation ameliorates ischemic renal failure.

    PubMed

    Jeyarajah, D Rohan; Kielar, Mariusz L; Zhou, Xin J; Zhang, Ying; Lu, Christopher Y

    2003-01-01

    Biliary obstruction affects the renal response to ischemia and also elicits a hepatic cytokine response. Using a murine model, we now test the hypothesis that these hepatic cytokines help determine the outcome of ischemic acute renal failure. C3H/HEN mice were subjected to bile duct ligation 24 h (ABDL) or 7 days (CBDL) prior to induction of acute ischemic renal failure (ARF). Serum creatinine (Scr), cytokine mRNA abundance, and renal histology were studied 24 h after renal ischemia. ABDL prior to ARF resulted in amelioration of renal injury (Scr 0.7 +/- 0.1 mg/dl compared to 2.5 +/- 0.1 mg/dl in sham/ARF group, (mean +/- SE, n = 11/group). CBDL exacerbated renal injury. Increased hepatic mRNA for interleukin-10 (IL10) and interleukin-1 receptor antagonist (IL1RA) was detected in the ABDL/ARF group but not in the CBDL/ARF group. These data suggest that hepatic production of IL10 and IL1RA in response to ABDL ameliorates ischemic ARF, an effect that is lost after several days of BDL. Our data support the concept that hepatic cytokines modulate renal injury. This adds a new dimension in our understanding of renal injury in the setting of hepatic disease. Copyright 2003 S. Karger AG, Basel

  18. Melatonin Alleviates Liver Apoptosis in Bile Duct Ligation Young Rats.

    PubMed

    Sheen, Jiunn-Ming; Chen, Yu-Chieh; Hsu, Mei-Hsin; Tain, You-Lin; Huang, Ying-Hsien; Tiao, Mao-Meng; Li, Shih-Wen; Huang, Li-Tung

    2016-08-20

    Bile duct ligation (BDL)-treated rats display cholestasis and liver damages. The potential protective activity of melatonin in young BDL rats in terms of apoptosis, mitochondrial function, and endoplasmic reticulum (ER) homeostasis has not yet been evaluated. Three groups of young male Sprague-Dawley rats were used: one group received laparotomy (Sham), a second group received BDL for two weeks (BDL), and a third group received BDL and intraperitoneal melatonin (100 mg/day) for two weeks (BDL + M). BDL group rats showed liver apoptosis, increased pro-inflamamtory mediators, caspases alterations, anti-apoptotic factors changes, and dysfunction of ER homeostasis. Melatonin effectively reversed apoptosis, mainly through intrinsic pathway and reversed ER stress. In addition, in vitro study showed melatonin exerted its effect mainly through the melatonin 2 receptor (MT2) in HepG2 cells. In conclusion, BDL in young rats caused liver apoptosis. Melatonin rescued the apoptotic changes via the intrinsic pathway, and possibly through the MT2 receptor. Melatonin also reversed ER stress induced by BDL.

  19. Laparoscopic ligation of varicoceles: an anatomically superior operation.

    PubMed Central

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

    1993-01-01

    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

  20. Archaeal RNA ligase from thermoccocus kodakarensis for template dependent ligation.

    PubMed

    Zhang, Lei; Tripathi, Anubhav

    2017-01-02

    Nicking-sealing RNA ligases play a significant biological role in host defense and cellular repair, and have become an important molecular tool in biomedical engineering. Due to the propensity for RNA to form secondary structures, RNA modifying enzymes with elevated optimum temperatures are highly desired. Current characterized double stranded RNA ligases, such as the bacteriophage T4 RNA ligase 2, while possessing good template dependency, are not active at elevated temperatures. The few characterized RNA ligases from thermophiles exhibit high template independency. We synthesize and characterize here, KOD RNA ligase (KOD1Rnl), a thermostable and template dependent RNA ligase from the archaeon, Thermoccocus Kodakarensis. We disclose that a 13 time reduction in template independent ligation can be achieved with the addition of a single stranded DNase, such as RecJ. We also elucidate the effects of the presence of blood proteins on the activity of KOD1Rnl. Template dependent and thermostable RNA ligases, such as KOD RNA ligase, can be utilized in RNA detection, modification and sequencing.

  1. Expanded utility of the native chemical ligation reaction.

    PubMed

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

    2004-10-04

    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.

  2. [High ligation of the spermatic vein and sperm DNA fragmentation].

    PubMed

    Hu, Yang-yang; Lin, Li-zhang; Li, Cheng-di; Cai, Jian

    2011-10-01

    To investigate the effect of high ligation of the spermatic vein (HLSV) on DNA fragmentation in varicocele (VC) patients. Thirty-four VC patients underwent HLSV. Sperm motion indexes and the results of papanicolaou staining and DNA fragmentation detection were analyzed before and 3 months after the operation according to the WHO guidelines. Compared with pre-operation, HLSV achieved a significant increase in the percentage of morphologically normal sperm (P < 0.01), and remarkable decreases in DNA fragmentation, sperm deformity index (SDI) and multiple anomalies index (MAI) (P < 0.01). The patients also showed significant increases in sperm concentration and the percentages of grade b sperm (P < 0.05) and grade a and a + b sperm (P < 0.01) after the operation. The post-operative percentages of sperm DNA fragmentation in those with grades I - III VC were markedly lower (P < 0.01), but showed no significant difference from that in those with subclinical VC (P > 0.05). The percentage of big-halo sperm was significantly increased (P < 0.01), while those of the medium-, small- and non-halo sperm remarkably decreased (P < 0.01) after HLSV. HLSV can effectively improve the sperm quality of VC patients.

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

    PubMed Central

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

    2014-01-01

    AIM: To investigate the safety and efficacy of endoscopic 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 females, 46-86 years of age) treated between May 2009 and February 2014: duodenal vascular ectasia; 1, jejunal 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 formation. 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 a repeat 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. PMID:25324920

  4. Melatonin Alleviates Liver Apoptosis in Bile Duct Ligation Young Rats

    PubMed Central

    Sheen, Jiunn-Ming; Chen, Yu-Chieh; Hsu, Mei-Hsin; Tain, You-Lin; Huang, Ying-Hsien; Tiao, Mao-Meng; Li, Shih-Wen; Huang, Li-Tung

    2016-01-01

    Bile duct ligation (BDL)-treated rats display cholestasis and liver damages. The potential protective activity of melatonin in young BDL rats in terms of apoptosis, mitochondrial function, and endoplasmic reticulum (ER) homeostasis has not yet been evaluated. Three groups of young male Sprague-Dawley rats were used: one group received laparotomy (Sham), a second group received BDL for two weeks (BDL), and a third group received BDL and intraperitoneal melatonin (100 mg/day) for two weeks (BDL + M). BDL group rats showed liver apoptosis, increased pro-inflamamtory mediators, caspases alterations, anti-apoptotic factors changes, and dysfunction of ER homeostasis. Melatonin effectively reversed apoptosis, mainly through intrinsic pathway and reversed ER stress. In addition, in vitro study showed melatonin exerted its effect mainly through the melatonin 2 receptor (MT2) in HepG2 cells. In conclusion, BDL in young rats caused liver apoptosis. Melatonin rescued the apoptotic changes via the intrinsic pathway, and possibly through the MT2 receptor. Melatonin also reversed ER stress induced by BDL. PMID:27556445

  5. Identification of members of several homeobox genes in a planarian using a ligation-mediated polymerase chain reaction technique.

    PubMed Central

    Balavoine, G

    1996-01-01

    I have used a novel single-sided specific polymerase chain reaction (PCR) strategy inspired by ligation-mediated PCR to clone fragments of divergent homeobox genes from a flatworm, the planarian Polycelis nigra. Eight homeobox-containing fragments were amplified, belonging to the Hox, msh, NK-1 and NK-2 classes. Together with the results obtained from several genomes of platyhelminths, my screening shows the presence of the same array of homeodomain developmental regulators in planarians, traditionally regarded as primitive metazoans in terms of body plan, as in coelomate organisms. However, the presence of a Ubx/abd-A homolog may indicate that platyhelminths are more closely related to protostomes than to deuterostomes and supports the idea that flatworms have inherited an elaborate HOX cluster (seven or eight genes) from their ancestor. Likely homologs of the fly genes tinman, bagpipe and S59 suggest that the mesoderm might be patterned by the same genes in all bilaterally symmetrical animals. Finally, a msh-like gene, a family known to be involved in inductive mechanisms in vertebrates, has been found. These results support the hypothesis that the tremendous diversity of metazoan body plans is specified by a largely conserved array of homeobox-containing developmental genes. PMID:8628690

  6. Ligation-mediated PCR, a fast and reliable technique for insertion sequence-based typing of Xanthomonas citri pv. citri.

    PubMed

    Ngoc, Lan Bui Thi; Vernière, Christian; Belasque, José Júnior; Vital, Karine; Boutry, Sébastien; Gagnevin, Lionel; Pruvost, Olivier

    2008-11-01

    Asiatic citrus canker, caused by Xanthomonas citri pv. citri, is a major disease threatening citrus crops throughout the world. The most common methods for strain differentiation of this pathogen are repetitive element sequence-based PCR (rep-PCR) and pulsed field gel electrophoresis (PFGE), using rare-cutting restriction enzyme analysis. We developed a ligation-mediated PCR targeting three insertion sequences (IS-LM-PCR) present as several copies in the genome of the fully sequenced strain 306 of X. citri pv. citri. This technique amplifies DNA fragments between an insertion sequence element and an MspI restriction site. The analysis of strains can be conducted within 24 h, starting from very small amounts of bacterial DNA, which makes IS-LM-PCR much less labor-intensive than PFGE. We used IS-LM-PCR to analyze a collection of 66 strains of X. citri pv. citri from around the world. The overall reproducibility of IS-LM-PCR reached 98% in this data set and its discriminatory power was markedly superior than rep-PCR. We suggest that IS-LM-PCR could be used for the global surveillance of non-epidemiologically related strains of X. citri pv. citri.

  7. Method for preparing single-stranded DNA templates for Pyrosequencing using vector ligation and universal biotinylated primers.

    PubMed

    Groth, Marco; Huse, Klaus; Reichwald, Kathrin; Taudien, Stefan; Hampe, Jochen; Rosenstiel, Philip; Birkenmeier, Gerd; Schreiber, Stefan; Platzer, Matthias

    2006-09-15

    In Pyrosequencing, the addition of nucleotides to a primer-template hybrid is monitored by enzymatic conversion of chemical energy into detectable light. The technique yields both qualitative and quantitative sequence information because the chemical energy is released by a stoichiometric split off of pyrophosphates from incorporated deoxynucleotide triphosphates and a defined nucleotide dispensation order is given. Because Pyrosequencing works best if single-stranded DNA templates are used, template generation usually requires PCR with a target-specific biotinylated primer and a subsequent purification involving interaction of the biotin label with immobilized streptavidin. To circumvent the need for numerous and expensive template-specific biotinylated primers, we developed a method that uses the ligation of amplified DNA fragments into a plasmid vector, thereby facilitating subsequent PCR using a universal vector-specific biotinylated primer. This approach allows easy and straightforward isolation of single-stranded templates of any PCR product. As a proof of principle, we used the method for genotyping two single-nucleotide polymorphisms in the human genes CARD15 and A2M and for characterization of four multisite variations in the human DEFB104 gene.

  8. Generating Entangled State with Parametric Amplifier

    NASA Astrophysics Data System (ADS)

    Huang, Jian

    2017-04-01

    We present a scheme for generating entangled state with parametric amplifier with different initial states. Its shown that the entangled state is always generated except some special cases by adjusting the coupling strength and the total number of photons.

  9. Operational Amplifier Experiments for the Chemistry Laboratory.

    ERIC Educational Resources Information Center

    Braun, Robert D.

    1996-01-01

    Provides details of experiments that deal with the use of operational amplifiers and are part of a course in instrumental analysis. These experiments are performed after the completion of a set of electricity and electronics experiments. (DDR)

  10. Noise in phase-preserving linear amplifiers

    SciTech Connect

    Pandey, Shashank; Jiang, Zhang; Combes, Joshua; Caves, Carlton M.

    2014-12-04

    The purpose of a phase-preserving linear amplifier is to make a small signal larger, so that it can be perceived by instruments incapable of resolving the original signal, while sacrificing as little as possible in signal-to-noise. Quantum mechanics limits how well this can be done: the noise added by the amplifier, referred to the input, must be at least half a quantum at the operating frequency. This well-known quantum limit only constrains the second moments of the added noise. Here we provide the quantum constraints on the entire distribution of added noise: any phasepreserving linear amplifier is equivalent to a parametric amplifier with a physical state σ for the ancillary mode; σ determines the properties of the added noise.

  11. Cryogenic Amplifier Based Receivers at Submillimeter Wavelengths

    NASA Technical Reports Server (NTRS)

    Chattopadhyay, Goutam; Reck, Theodore and; Schlecht, Erich; Lin, Robert; Deal, William

    2012-01-01

    The operating frequency of InP high electron mobility transistor (HEMT) based amplifiers has moved well in the submillimeter-wave frequencies over the last couple of years. Working amplifiers with usable gain in waveguide packages has been reported beyond 700 GHz. When cooled cryogenically, they have shown substantial improvement in their noise temperature. This has opened up the real possibility of cryogenic amplifier based heterodyne receivers at submillimeter wavelengths for ground-based, air-borne, and space-based instruments for astrophysics, planetary, and Earth science applications. This paper provides an overview of the science applications at submillimeter wavelengths that will benefit from this technology. It also describes the current state of the InP HEMT based cryogenic amplifier receivers at submillimeter wavelengths.

  12. High bandwidth differential amplifier for shock experimentsa)

    NASA Astrophysics Data System (ADS)

    Ross, P. W.; Tran, V.; Chau, R.

    2012-10-01

    We developed a high bandwidth differential amplifier for gas gun shock experiments of low-resistance metals. The circuit has a bandwidth up to 1 GHz, and is capable of measuring signals of ≤1.5 V with a common mode rejection of 250 V. Conductivity measurements of gas gun targets are measured by flowing high currents through the targets. The voltage is measured across the target using a technique similar to a four-point probe. Because of the design of the current source and load, the target voltage is ˜250 V relative to ground. Since the expected voltage change in the target is <1 V, the differential amplifier must have a large common mode rejection. Various amplifying designs are shown, although the increased amplification decreases bandwidth. Bench tests show that the amplifier can withstand significant common mode dc voltage and measure 10 ns, and 50 mV signals.

  13. How to characterize the nonlinear amplifier?

    NASA Technical Reports Server (NTRS)

    Kallistratova, Dmitri Kouznetsov; Cotera, Carlos Flores

    1994-01-01

    The conception of the amplification of the coherent field is formulated. The definition of the coefficient of the amplification as the relation between the mean value of the field at the output to the value at the input and the definition of the noise as the difference between the number of photons in the output mode and square of the modulus of the mean value of the output amplitude are considered. Using a simple example it is shown that by these definitions the noise of the nonlinear amplifier may be less than the noise of the ideal linear amplifier of the same amplification coefficient. Proposals to search another definition of basic parameters of the nonlinear amplifiers are discussed. This definition should enable us to formulate the universal fundamental lower limit of the noise which should be valid for linear quantum amplifiers as for nonlinear ones.

  14. Tester periodically registers dc amplifier characteristics

    NASA Technical Reports Server (NTRS)

    Cree, D.; Wenzel, G. E.

    1966-01-01

    Motor-driven switcher-recorder periodically registers the zero drift and gain drift signals of a dc amplifier subjected to changes in environment. A time coding method is used since several measurements are shared on a single recorder trace.

  15. Signal amplifier-shapers for multiwire detectors

    NASA Astrophysics Data System (ADS)

    Bushnin, Yu. B.; Konoplyannikov, A. K.

    Circuit diagram and specification of 8 and 16 channel modules of amplifier-shapers are described for multiwire detectors. The modules have input impedance 200 Ohm sensitivity threshold 1.5 micro-A, output pulse width 80 nsec.

  16. Ku band low noise parametric amplifier

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A low noise, K sub u-band, parametric amplifier (paramp) was developed. The unit is a spacecraft-qualifiable, prototype, parametric amplifier for eventual application in the shuttle orbiter. The amplifier was required to have a noise temperature of less than 150 K. A noise temperature of less than 120 K at a gain level of 17 db was achieved. A 3-db bandwidth in excess of 350 MHz was attained, while deviation from phase linearity of about + or - 1 degree over 50 MHz was achieved. The paramp operates within specification over an ambient temperature range of -5 C to +50 C. The performance requirements and the operation of the K sub u-band parametric amplifier system are described. The final test results are also given.

  17. Operational Amplifier Experiments for the Chemistry Laboratory.

    ERIC Educational Resources Information Center

    Braun, Robert D.

    1996-01-01

    Provides details of experiments that deal with the use of operational amplifiers and are part of a course in instrumental analysis. These experiments are performed after the completion of a set of electricity and electronics experiments. (DDR)

  18. Defibrillator-embedded rapid recovery electrocardiogram amplifier.

    PubMed

    Neycheva, T; Krasteva, V

    2003-01-01

    One of the most important performances of the defibrillator-embedded amplifier-monitor-recorder tract, connected to defibrillator electrodes, is its rapid recovery after the application of the shock pulse. Practically near-immediate restoration of the signal trace is mandatory for studies of post-shock effects on the myocardium. Automatic analysis of the electrocardiogram signal in public-access defibrillation, aiming for about 100% correct recognition of shockable and non-shockable rhythms, now requires fast amplifier settling, as the decision time should not exceed 10-20 s. Two circuits of post-shock amplifier transient suppressors were developed with non-linear feedback, resulting in second-order high-pass filtering, with gradual return to normally accepted first-order response. Simulation and testing in real conditions resulted in recovery periods in the range of 1-2 s for an amplifier tract of 1-30 Hz bandwidth, depending on the pulse waveform and electrode type.

  19. Amplifiers of free-space terahertz radiation

    DOE PAGES

    Kao, Tsung -Yu; Reno, John L.; Hu, Qing

    2017-07-20

    Here, amplifiers of free-space radiation are quite useful, especially in spectral ranges where the radiation is weak and sensitive detectors are hard to come by. A preamplification of the said weak radiation signal will significantly boost the S/N ratio in remote sensing and imaging applications. This is especially true in the terahertz (THz) range where the radiation signal is often weak and sensitive detectors require the cooling of liquid helium. Although quantum cascade structures are promising for providing amplification in the terahertz band from 2 to 5 THz, a THz amplifier has been demonstrated in an integrated form, in whichmore » the source is in close proximity to the amplifier, which will not be suitable for the aforementioned applications. Here we demonstrate what we believe is a novel approach to achieve significant amplification of free-space THz radiation using an array of short-cavity, surface-emitting THz quantum cascade lasers operating marginally below the lasing threshold as a Fabry–Perot amplifier. This free-space “slow light” amplifier provides 7.5 dB(×5.6) overall gain at ~3.1 THz. The proposed devices are suitable for low-noise pre-amplifiers in heterodyne detection systems and for THz imaging systems. With the sub-wavelength pixel size of the array, the reflective amplifier can also be categorized as active metasurface, with the ability to amplify or absorb specific frequency components of the input THz signal.« less

  20. Direct solar-pumped iodine laser amplifier

    NASA Technical Reports Server (NTRS)

    Han, Kwang S.; Hwang, In Heon; Stock, Larry V.

    1989-01-01

    This semiannual progress report covers the period from September 1, 1988 to February 28, 1989 under NASA grant NAG-1-441 entitled, Direct Solar-Pumped Iodine Laser Amplifier. During this period, the research effort was concentrated on the solar pumped master oscillator power amplifier (MOPA) system using n-C3F7I. In the experimental work, the amplification measurement was conducted to identify the optimum conditions for amplification of the center's Vortek solar simulator pumped iodine laser amplifier. A modeling effort was also pursued to explain the experimental results in the theoretical work. The amplification measurement of the solar simulator pumped iodine laser amplifier is the first amplification experiment on the continuously pumped amplifier. The small signal amplification of 5 was achieved for the triple pass geometry of the 15 cm long solar simulator pumped amplifier at the n-C3F7I pressure of 20 torr, at the flow velocity of 6 m/sec and at the pumping intensity of 1500 solar constants. The XeCl laser pumped iodine laser oscillator, which was developed in the previous research, was employed as the master oscillator for the amplification measurement. In the theoretical work, the rate equations of the amplifier was established and the small signal amplification was calculated for the solar simulator pumped iodine laser amplifier. The amplification calculated from the kinetic equations with the previously measured rate coefficients reveals very large disagreement with experimental measurement. Moreover, the optimum condition predicted by the kinetic equation is quite discrepant with that measured by experiment. This fact indicates the necessity of study in the measurement of rate coefficients of the continuously pumped iodine laser system.

  1. MMIC Amplifiers for 90 to 130 GHz

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    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.

  2. Efficient Power Amplifier for Motor Control

    NASA Technical Reports Server (NTRS)

    Brown, R. J.

    1986-01-01

    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.

  3. Bolometers - Ultimate sensitivity, optimization, and amplifier coupling

    NASA Technical Reports Server (NTRS)

    Mather, J. C.

    1984-01-01

    Theoretical expressions for Johnson noise and thermal noise in bolometers are considered, and optimization with respect to thermal conductivity and bias power is performed. Numerical approximations are given for the ultimate NEP of bolometers as a function of material parameters and compared with photon noise including photon correlations. A resonating capacitor is shown to improve the coupling to an amplifier, so that the amplifier need not limit performance even for very low temperature bolometers.

  4. Chemoselective modifications for the traceless ligation of thioamide-containing peptides and proteins.

    PubMed

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

    2016-07-14

    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.

  5. Western blot analysis of Src kinase assays using peptide substrates ligated to a carrier protein.

    PubMed

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

    2004-06-01

    We have applied intein-mediated peptide ligation (IPL) to the use of peptide substrates for kinase assays and subsequent Western blot analysis. IPL allows for the efficient ligation of a synthetic peptide with an N-terminal cysteine residue to an intein-generated carrier protein containing a cysteine reactive C-terminal thioester through a native peptide bond. A distinct advantage of this procedure is that each carrier protein molecule ligates only one peptide, ensuring that the ligation product forms a sharp band on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). We demonstrate the effectiveness of this approach by mutational analysis of peptide substrates derived from human cyclin-dependent kinase, Cdc2, which contains a phosphorylation site of human c-Src protein tyrosine kinase.

  6. The course and nature of acinar cell death following pancreatic ligation in the guinea pig.

    PubMed

    Zeligs, J D; Janoff, A; Dumont, A E

    1975-08-01

    The course and nature of acinar cell death (ACD) following pancreatic ligation in the guinea pig was studied as a possible model for human disease. Ultrastructural studies after various periods of ligation suggested a biphasic pattern of ACD. Early phase ACD involved only a small portion of acinar cells and occurred within a few hours of ligation. It was preceded by swelling and vesiculation of the rough endoplasmic reticulum. Morphometric measurements disclosed celular swelling at this time, and NaCl equilibration studies demonstrated a change in cellular osmoregulation. Late phase ACD, characterized by cellular wasting and autophagic vacuole formation, became prominent several days after ligation. Marked increases in lysosomal enzyme activities were found in tissue homogenates at this time, and acid phosphatase electron histochemistry localized the majority of this increased activity to lysosomes and autophagic vacuoles within the acinar cells. The etiology and nature of both phases of ACD are discussed.

  7. Heated oligonucleotide ligation assay (HOLA): an affordable single nucleotide polymorphism assay.

    PubMed

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

    2006-03-01

    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.

  8. Common Carotid Artery Ligation to Minimize Blood Loss During Oral and Maxillofacial Surgery.

    PubMed

    Goodman, Alice E; Goodman, Andrew R

    2016-09-01

    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.

  9. Nonenzymatic ligation of an RNA oligonucleotide analyzed by atomic force microscopy.

    PubMed

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

    2011-05-19

    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.

  10. Generating site-specifically modified proteins via a versatile and stable nucleophilic carbon ligation.

    PubMed

    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

    2015-02-19

    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.

  11. Interrupting Rivaling Access-flow with Nonsurgical Image-guided ligation: the "IRANI" Procedure.

    PubMed

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

    2015-01-01

    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.

  12. Some Notes on Wideband Feedback Amplifiers

    DOE R&D Accomplishments Database

    Fitch, V.

    1949-03-16

    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.

  13. V-band IMPATT power amplifier

    NASA Technical Reports Server (NTRS)

    Schell, S. W.

    1985-01-01

    This program is the result of the continuing demand and future requirement for a high data rate 60-GHz communications link. A reliable solid-state transmitter which delivers the necessary power over a wide bandwidth using the present IMPATT diode technology required the development of combining techniques. The development of a 60-GHz IMPATT power combiner amplifier is detailed. The results form a basis from which future wideband, high-power IMPATT amplifiers may be developed. As a result, several state-of-the-art advancements in millimeter-wave components technology were achieved. Specific achievements for the amplifier integration were: development of a nonresonant divider/combiner circuit; reproducible multiple junction circulator assemblies; and reliable high power 60-GHz IMPATT diodes. The various design approaches and tradeoffs which lead to the final amplifier configuration are discussed. A detailed circuit design is presented for the various amplifier components, and the conical line combiner, radial line combiner, and circulator development are discussed. The performance of the amplifier, the overall achievement of the program, the implications of the results, and an assessment of future development needs and recommendations are examined.

  14. Multiple excitation regenerative amplifier inertial confinement system

    DOEpatents

    George, Victor E. [Livermore, CA; Haas, Roger A. [Pleasanton, CA; Krupke, William F. [Pleasanton, CA; Schlitt, Leland G. [Livermore, CA

    1980-05-27

    The invention relates to apparatus and methods for producing high intensity laser radiation generation which is achieved through an optical amplifier-storage ring design. One or two synchronized, counterpropagating laser pulses are injected into a regenerative amplifier cavity and amplified by gain media which are pumped repetitively by electrical or optical means. The gain media excitation pulses are tailored to efficiently amplify the laser pulses during each transit. After the laser pulses have been amplified to the desired intensity level, they are either switched out of the cavity by some switch means, as for example an electro-optical device, for any well known laser end uses, or a target means may be injected into the regenerative amplifier cavity in such a way as to intercept simultaneously the counterpropagating laser pulses. One such well known end uses to which this invention is intended is for production of high density and temperature plasmas suitable for generating neutrons, ions and x-rays and for studying matter heated by high intensity laser radiation.

  15. Multiple excitation regenerative amplifier inertial confinement system

    DOEpatents

    George, V.E.; Haas, R.A.; Krupke, W.F.; Schlitt, L.G.

    1980-05-27

    The invention relates to apparatus and methods for producing high intensity laser radiation generation which is achieved through an optical amplifier-storage ring design. One or two synchronized, counterpropagating laser pulses are injected into a regenerative amplifier cavity and amplified by gain media which are pumped repetitively by electrical or optical means. The gain media excitation pulses are tailored to efficiently amplify the laser pulses during each transit. After the laser pulses have been amplified to the desired intensity level, they are either switched out of the cavity by some switch means, as for example an electro-optical device, for any well known laser end uses, or a target means may be injected into the regenerative amplifier cavity in such a way as to intercept simultaneously the counterpropagating laser pulses. One such well known end uses to which this invention is intended is for production of high density and temperature plasmas suitable for generating neutrons, ions and x-rays and for studying matter heated by high intensity laser radiation. 11 figs.

  16. The impact of a dedicated patent ductus arteriosus ligation team on neonatal health-care outcomes.

    PubMed

    Resende, M H F; More, K; Nicholls, D; Ting, J; Jain, A; McNamara, P J

    2016-06-01

    The decision to perform patent ductus arteriosus (PDA) ligation is controversial. Patient selection is oftentimes poorly standardized, leading to delays in referral and inappropriate intervention. A system for PDA ligation categorization and triaging process was introduced in 2006 at a quaternary hospital in Canada to streamline referrals and enhance perioperative care. We aimed to evaluate the impact of this dedicated PDA ligation triaging system comparing pre- and postimplementation of this system. We performed a retrospective chart review. Demographic and cardiorespiratory data of neonates ⩽30 weeks gestation age at birth, who were referred for and/or had a PDA ligation performed during two distinct epochs (EPOCH 1 (2003 to 2005) and EPOCH 2 (2010 to 2012)), were analyzed. All surgeries were performed at The Hospital for Sick Children, the regional referral center for PDA ligation. The primary outcome was incidence of PDA ligation and procedural cancellations. Secondary outcomes included postoperative need for cardiovascular or respiratory support. Subgroup analysis was performed in neonates <1000 vs >1000 g at the time of surgery during both epochs. A total of 198 neonates underwent surgery with no difference in baseline demographics between epochs. The incidence of PDA ligation as a proportion of total live births under 30 weeks in Central East Region of Ontario was lower in the second epoch (EPOCH 1: 117/1092 (10.7%) vs EPOCH 2: 81/1520 (5.3%)). During the second epoch, 24% of referrals for surgery were canceled after review by our PDA ligation team. There were no overall differences in the proportion of neonates with oxygenation failure, ventilation failure or Post-Ligation Cardiac Syndrome (PLCS), after surgery, between epochs. The proportion of neonates who developed systemic hypotension was higher in patients <1000 g (n=34 (34%) vs n=17 (17.4%), P=0.01) at the time of surgery. In addition, we identified a reduction in the proportion of neonates

  17. Hypermutable ligation of plasmid DNA ends in cells from patients with Werner syndrome.

    PubMed

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

    1994-01-01

    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.

  18. Gold nanoparticle-enabled real-time ligation chain reaction for ultrasensitive detection of DNA.

    PubMed

    Shen, Wei; Deng, Huimin; Gao, Zhiqiang

    2012-09-12

    A simple and ultrasensitive colorimetric DNA assay based on the detection of the product of a ligation chain reaction (LCR) and the use of gold nanoparticles (AuNPs) as signal generators has been developed. During LCR, the AuNPs were ligated together, resulting in a distinct color change in real time after a sufficient number of thermal cycles. The cumulative nature of the protocol produced a detection limit of 20 aM with a selectivity factor of 10(3).

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

    PubMed Central

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

    2008-01-01

    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. PMID:18567081

  20. Ligation-assisted endoscopic submucosal resection with circumferential mucosal incision for duodenal carcinoid tumor.

    PubMed

    Harada, Hideaki; Suehiro, Satoshi; Shimizu, Takanori; Katsuyama, Yasushi; Hayasaka, Kenji; Ito, Hideto

    2015-09-14

    Here we present the case of a 64-year-old female with a duodenal carcinoid tumor treated by ligation-assisted endoscopic submucosal resection (ESMR-L) with circumferential mucosal incision (CMI). Band ligation was effective in resecting the duodenal carcinoid tumor after CMI, with an uneventful post-procedural course. Histopathological examination showed clear tumor margins at deeper tissue levels. Thus, in the present case, ESMR-L with CMI was useful for the treatment of duodenal carcinoid tumor.

  1. Outcome following patent ductus arteriosus ligation in premature infants: a retrospective cohort analysis

    PubMed Central

    Lee, LLeona CL; Tillett, Angela; Tulloh, Robert; Yates, Robert; Kelsall, Wilf

    2006-01-01

    Background The patent ductus arteriosus (PDA) is an important problem in premature infants. Surgical PDA ligation is usually only be considered when medical treatment has either failed or was contraindicated. The aims of our study were to determine the mortality and morbidity following patent ductus arteriosus ligation in premature infants, and whether prostaglandin synthetase inhibitor (PSI) use prior to ligation affects outcome. Methods A retrospective case note review study to determine the outcome of premature infants undergoing patent ductus arteriosus ligation in one tertiary neonatal intensive care unit and two paediatric cardiothoracic centres. Results We had follow-up data on 87 infants. Cumulative mortality rates at 7 days, 30 days and at hospital discharge were 2%, 8% and 20% respectively. The incidence of chronic lung disease, intraventricular haemorrhage, necrotising enterocolitis and retinopathy of prematurity were 77%, 39%, 26% and 28% respectively. There was no difference in mortality, incidence of chronic lung disease or duration of oxygen dependence between those who had and those who had not received a PSI prior to surgical ligation. In those who had received 2 or more courses of PSI prior to surgical ligation, there was a trend to increase in the duration of oxygen therapy and chronic lung disease, but no difference in mortality. Conclusion This study shows that patent ductus arteriosus ligation is a relatively safe procedure (30 day survival 92%) but there is substantial late mortality and a high incidence of morbidity in the survivors. 2 or more courses of PSI prior to surgical ligation trends to increased oxygen dependence and chronic lung disease. This high risk population requires careful follow-up. A definitive prospective cohort study is lacking. PMID:16689986

  2. Triple rubber band ligation for hemorrhoids: prospective, randomized trial of use of local anesthetic injection.

    PubMed

    Law, W L; Chu, K W

    1999-03-01

    Rubber band ligation is a common office procedure for hemorrhoids. Triple rubber band ligation in a single session has been shown to be a safe and economical way of treating hemorrhoids. However, postligation discomfort after triple rubber band ligation is not uncommon. The aim of this study was to evaluate the effectiveness of local anesthetic injection to the banded hemorrhoidal tissue in reducing postligation discomfort. Patients attending an outpatient clinic for symptomatic hemorrhoids suitable for triple rubber band ligation were randomly assigned to two groups. In the treatment group rubber band ligation was performed at three columns of hemorrhoids, and 1 to 2 ml of 2 percent lignocaine was injected into the banded hemorrhoidal tissue. In the control group triple rubber band ligation was performed in a similar manner, but local anesthetic was not given. Patients were followed up by telephone at the second week and in the clinic after six weeks. From April to August 1996, 101 patients entered the trial and were treated with triple rubber band ligation. Sixty-two patients were randomly assigned to the local anesthetic injection group and 39 to the control group. Overall good to excellent results occurred in 89 percent of patients, and there was no difference between the two groups. Postligation pain occurred in 26 and 20 percent of patients in the treatment and control groups, respectively (P > 0.05). Postligation tenesmus occurred in 32 and 41 percent of patients in the treatment and control groups, respectively (P > 0.05). No patients suffered from septic complications or bleeding that required transfusion. Triple rubber band ligation in a single session is a safe, economical, and effective way of treating symptomatic hemorrhoids. Postligation pain and tenesmus occurred in 24 and 37 percent, respectively. Discomfort was usually tolerable. Local anesthetic injection to the banded hemorrhoidal tissue did not help to reduce postligation discomfort.

  3. Ligation-assisted endoscopic submucosal resection with circumferential mucosal incision for duodenal carcinoid tumor

    PubMed Central

    Harada, Hideaki; Suehiro, Satoshi; Shimizu, Takanori; Katsuyama, Yasushi; Hayasaka, Kenji; Ito, Hideto

    2015-01-01

    Here we present the case of a 64-year-old female with a duodenal carcinoid tumor treated by ligation-assisted endoscopic submucosal resection (ESMR-L) with circumferential mucosal incision (CMI). Band ligation was effective in resecting the duodenal carcinoid tumor after CMI, with an uneventful post-procedural course. Histopathological examination showed clear tumor margins at deeper tissue levels. Thus, in the present case, ESMR-L with CMI was useful for the treatment of duodenal carcinoid tumor. PMID:26379409

  4. Synthesis of cysteine-rich peptides by native chemical ligation without use of exogenous thiols.

    PubMed

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

    2015-04-03

    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.

  5. Combining ligation reaction and capillary gel electrophoresis to obtain reliable long DNA probes.

    PubMed

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

    2011-05-01

    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

  6. Low Noise Optically Pre-amplified Lightwave Receivers and Other Applications of Fiber Optic Parametric Amplifiers

    DTIC Science & Technology

    2010-07-27

    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

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

    PubMed Central

    Braun, Klaus; Wiessler, Manfred; Ehemann, Volker; Pipkorn, Ruediger; Spring, Herbert; Debus, Juergen; Didinger, Bernd; Koch, Mario; Muller, Gabriele; Waldeck, Waldemar

    2008-01-01

    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. PMID:19920915

  8. Insights into the mechanism and catalysis of the native chemical ligation reaction.

    PubMed

    Johnson, Erik C B; Kent, Stephen B H

    2006-05-24

    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.

  9. Formation of oligonucleotide-PNA-chimeras by template-directed ligation

    NASA Technical Reports Server (NTRS)

    Koppitz, M.; Nielsen, P. E.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1998-01-01

    DNA sequences have previously been reported to act as templates for the synthesis of PNA, and vice versa. A continuous evolutionary transition from an informational replicating system based on one polymer to a system based on the other would be facilitated if it were possible to form chimeras, that is molecules that contain monomers of both types. Here we show that ligation to form chimeras proceeds efficiently both on PNA and on DNA templates. The efficiency of ligation is primarily determined by the number of backbone bonds at the ligation site and the relative orientation of template and substrate strands. The most efficient reactions result in the formation of chimeras with ligation junctions resembling the structures of the backbones of PNA and DNA and with antiparallel alignment of both components of the chimera with the template, that is, ligations involving formation of 3'-phosphoramidate and 5'-ester bonds. However, double helices involving PNA are stable both with antiparallel and parallel orientation of the two strands. Ligation on PNA but not on DNA templates is, therefore, sometimes possible on templates with reversed orientation. The relevance of these findings to discussions of possible transitions between genetic systems is discussed.

  10. Prospective comparison of ligation and bipolar cautery technique in non-scalpel vasectomy

    PubMed Central

    Altok, Muammer; Şahin, Ali Feyzullah; Divrik, Rauf Taner; Yildirim, Ümit; Zorlu, Ferruh

    2015-01-01

    ABSTRACT Objectives: There is no trial comparing bipolar cautery and ligation for occlusion of vas in non-scalpel vasectomy. This study aimed to compare the effectiveness of these vasectomy occlusion techniques. Materials and Methods: Between January 2002-June 2009, patients were allocated in alternate order. We recruited 100 cases in cautery group and 100 cases in ligation group. Non-scalpel approach was performed during vasectomy and fascial interposition was performed in all cases. First semen analysis was done 3 months after vasectomy. Vasectomy success was defined as azoospermia or non-motile sperm lower than 100.000/mL. Results: Four patients from the cautery group were switched to the ligation group due to technical problem of cautery device. Thus, data of 96 patients as cautery group and 104 patients as ligation group were evaluated. After vasectomy, semen analyses were obtained from 59 of 96 (61.5%) patients in cautery group and to 66 of 104 (63.5%) patients in ligation group. There was no statistical significant difference between the two groups in terms of the success of vasectomy (p=0.863). Conclusion: Although bipolar cautery technique is safe, effective and feasible in non-scalpel vasectomy, it has no superiority to ligation. There was no statistically significant difference in terms of the success and complications between the two groups. PMID:26742977

  11. Blood flow changes after unilateral carotid artery ligation monitored by optical coherence tomography

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    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.

  12. Formation of oligonucleotide-PNA-chimeras by template-directed ligation

    NASA Technical Reports Server (NTRS)

    Koppitz, M.; Nielsen, P. E.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1998-01-01

    DNA sequences have previously been reported to act as templates for the synthesis of PNA, and vice versa. A continuous evolutionary transition from an informational replicating system based on one polymer to a system based on the other would be facilitated if it were possible to form chimeras, that is molecules that contain monomers of both types. Here we show that ligation to form chimeras proceeds efficiently both on PNA and on DNA templates. The efficiency of ligation is primarily determined by the number of backbone bonds at the ligation site and the relative orientation of template and substrate strands. The most efficient reactions result in the formation of chimeras with ligation junctions resembling the structures of the backbones of PNA and DNA and with antiparallel alignment of both components of the chimera with the template, that is, ligations involving formation of 3'-phosphoramidate and 5'-ester bonds. However, double helices involving PNA are stable both with antiparallel and parallel orientation of the two strands. Ligation on PNA but not on DNA templates is, therefore, sometimes possible on templates with reversed orientation. The relevance of these findings to discussions of possible transitions between genetic systems is discussed.

  13. Chemical Ligation of Folded Recombinant Proteins: Segmental Isotopic Labeling of Domains for NMR Studies

    NASA Astrophysics Data System (ADS)

    Xu, Rong; Ayers, Brenda; Cowburn, David; Muir, Tom W.

    1999-01-01

    A convenient in vitro chemical ligation strategy has been developed that allows folded recombinant proteins to be joined together. This strategy permits segmental, selective isotopic labeling of the product. The src homology type 3 and 2 domains (SH3 and SH2) of Abelson protein tyrosine kinase, which constitute the regulatory apparatus of the protein, were individually prepared in reactive forms that can be ligated together under normal protein-folding conditions to form a normal peptide bond at the ligation junction. This strategy was used to prepare NMR sample quantities of the Abelson protein tyrosine kinase-SH(32) domain pair, in which only one of the domains was labeled with 15N Mass spectrometry and NMR analyses were used to confirm the structure of the ligated protein, which was also shown to have appropriate ligand-binding properties. The ability to prepare recombinant proteins with selectively labeled segments having a single-site mutation, by using a combination of expression of fusion proteins and chemical ligation in vitro, will increase the size limits for protein structural determination in solution with NMR methods. In vitro chemical ligation of expressed protein domains will also provide a combinatorial approach to the synthesis of linked protein domains.

  14. KAHA ligations that form aspartyl aldehyde residues as synthetic handles for protein modification and purification.

    PubMed

    Murar, Claudia E; Thuaud, Frédéric; Bode, Jeffrey W

    2014-12-31

    Aldehydes are widely recognized as valuable synthetic handles for the chemoselective manipulation of peptides and proteins. In this report, we show that peptides and small proteins containing the aspartic acid semialdehyde (Asa) side chain can be easily prepared by a chemoselective amide-forming ligation that results in the formation of the Asa residue at the ligation site. This strategy employs the α-ketoacid-hydroxylamine (KAHA) ligation in combination with a new isoxazolidine monomer that forms a side-chain aldehyde upon ligation. This monomer is easily prepared on a preparative scale by a catalytic, enantioselective approach and is readily introduced onto the N-terminus of a peptide segment by solid phase peptide synthesis. The ligated product can be further functionalized by bioorthogonal reactions between the aldehyde residue and alkoxyamines or hydrazides. We demonstrated that glucagon aldehyde, an unprotected 29-mer peptide prepared by KAHA ligation, can be site specifically and chemoselectively modified with biotin, dyes, aliphatic oximes, and hydroxylamines. We further describe a simple and high recovery one-step purification process based on the capture of a 29-mer glucagon aldehyde and a 76-mer ubiquitin aldehyde by an alkoxyamine-functionalized polyethylene glycol resin. The peptide or protein was released from the resin by addition of a hydroxylamine to provide the corresponding oximes.

  15. Protein-templated fragment ligations - from molecular recognition to drug discovery.

    PubMed

    Jaegle, Mike; Wong, Ee Lin; Tauber, Carolin; Nawrotzky, Eric; Arkona, Christoph; Rademann, Jörg

    2017-01-24

    The understanding and manipulation of molecular recognition events is the key to modern approaches in drug discovery. Protein-templated fragment ligation is a novel concept to support drug discovery and can help to improve the efficacy of already existing protein ligands. Protein-templated fragment ligations are chemical reactions between small molecules ("fragments") that utilize a protein´s surface as a template to combine and to form a protein ligand with increased binding affinity. The approach exploits the molecular recognition of reactive small molecule fragments by proteins both for ligand assembly and for the identification of bioactive fragment combinations. Chemical synthesis and bioassay are thus integrated in one single step. In this article we portrait the biophysical basis of reversible and irreversible fragment ligations and the available methods to detect protein-templated ligation products. The scope of known chemical reactions providing templated ligation products is reviewed and the possibilities to extend the reaction portfolio are discussed. Selected recent applications of the method in protein ligand discovery are reported. Finally, the strengths and limitations of the concept are discussed and an outlook on the future impact of templated fragment ligations on the drug discovery process is given.

  16. An efficient ligation reaction promoted by a Varkud Satellite ribozyme with extended 5'- and 3'-termini.

    PubMed

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

    2001-12-15

    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.

  17. Electrochemical detection of point mutation based on surface ligation reaction and biometallization.

    PubMed

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

    2008-05-15

    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.

  18. Effects of 2'-O-methyl nucleotide on ligation capability of T4 DNA ligase.

    PubMed

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

    2014-09-01

    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.

  19. Real Time Calibration Method for Signal Conditioning Amplifiers

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro J. (Inventor); Mata, Carlos T. (Inventor); Eckhoff, Anthony (Inventor); Perotti, Jose (Inventor); Lucena, Angel (Inventor)

    2004-01-01

    A signal conditioning amplifier receives an input signal from an input such as a transducer. The signal is amplified and processed through an analog to digital converter and sent to a processor. The processor estimates the input signal provided by the transducer to the amplifier via a multiplexer. The estimated input signal is provided as a calibration voltage to the amplifier immediately following the receipt of the amplified input signal. The calibration voltage is amplified by the amplifier and provided to the processor as an amplified calibration voltage. The amplified calibration voltage is compared to the amplified input signal, and if a significant error exists, the gain and/or offset of the amplifier may be adjusted as necessary.

  20. Real Time Calibration Method for Signal Conditioning Amplifiers

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro J. (Inventor); Mata, Carlos T. (Inventor); Eckhoff, Anthony (Inventor); Perotti, Jose (Inventor); Lucena, Angel (Inventor)

    2004-01-01

    A signal conditioning amplifier receives an input signal from an input such as a transducer. The signal is amplified and processed through an analog to digital converter and sent to a processor. The processor estimates the input signal provided by the transducer to the amplifier via a multiplexer. The estimated input signal is provided as a calibration voltage to the amplifier immediately following the receipt of the amplified input signal. The calibration voltage is amplified by the amplifier and provided to the processor as an amplified calibration voltage. The amplified calibration voltage is compared to the amplified input signal, and if a significant error exists, the gain and/or offset of the amplifier may be adjusted as necessary.

  1. Endoscopic band ligation for colonic diverticular bleeding: possibility of standardization

    PubMed Central

    Shimamura, Yuto; Ishii, Naoki; Omata, Fumio; Imamura, Noriatsu; Okamoto, Takeshi; Ego, Mai; Nakano, Kaoru; Ikeya, Takashi; Nakamura, Kenji; Takagi, Koichi; Fukuda, Katsuyuki; Fujita, Yoshiyuki

    2016-01-01

    Background and aims: Endoscopic band ligation (EBL) has been used to achieve hemostasis in patients with colonic diverticular bleeding. The safety and effectiveness of EBL when performed by non-expert endoscopists have not been sufficiently verified. This study aimed to elucidate the feasibility of the EBL technique when performed by non-expert endoscopists and of considering EBL as a standard treatment for colonic diverticular bleeding. Patients and methods: A retrospective cohort study was conducted in a tertiary referral center in Tokyo, Japan, between June 2009 and October 2014. A total of 95 patients treated with EBL were included in the study and were divided into two groups according to whether they had been treated by expert or non-expert endoscopists. Comorbidities, medications, shock index, hemoglobin level on admission, location of the bleeding diverticula, rate of bowel preparation, procedure time, and EBL-associated adverse events were evaluated in each group. Multivariate linear regression analyses were used to investigate factors related to EBL procedure time, which is the time elapsed between marking the site of bleeding with hemoclips and completion of the band release. Results: A total of 47 (49.5 %) procedures were performed by expert endoscopists. In a bivariate analysis, the median EBL procedure times in the expert and non-expert groups were 15 minutes (range 4 – 45) and 11 minutes (range 4 – 36), respectively (P = 0.03). When a multivariate linear regression model was used, EBL for right-sided diverticula was the factor most significantly affecting EBL procedure time. No adverse events were encountered. Conclusion: EBL can be safely and effectively performed by non-expert endoscopists. A right-sided location of diverticula was the factor most significantly affecting EBL procedure time. PMID:26878056

  2. Endoscopic band ligation for colonic diverticular bleeding: possibility of standardization.

    PubMed

    Shimamura, Yuto; Ishii, Naoki; Omata, Fumio; Imamura, Noriatsu; Okamoto, Takeshi; Ego, Mai; Nakano, Kaoru; Ikeya, Takashi; Nakamura, Kenji; Takagi, Koichi; Fukuda, Katsuyuki; Fujita, Yoshiyuki

    2016-02-01

    Endoscopic band ligation (EBL) has been used to achieve hemostasis in patients with colonic diverticular bleeding. The safety and effectiveness of EBL when performed by non-expert endoscopists have not been sufficiently verified. This study aimed to elucidate the feasibility of the EBL technique when performed by non-expert endoscopists and of considering EBL as a standard treatment for colonic diverticular bleeding. A retrospective cohort study was conducted in a tertiary referral center in Tokyo, Japan, between June 2009 and October 2014. A total of 95 patients treated with EBL were included in the study and were divided into two groups according to whether they had been treated by expert or non-expert endoscopists. Comorbidities, medications, shock index, hemoglobin level on admission, location of the bleeding diverticula, rate of bowel preparation, procedure time, and EBL-associated adverse events were evaluated in each group. Multivariate linear regression analyses were used to investigate factors related to EBL procedure time, which is the time elapsed between marking the site of bleeding with hemoclips and completion of the band release. A total of 47 (49.5 %) procedures were performed by expert endoscopists. In a bivariate analysis, the median EBL procedure times in the expert and non-expert groups were 15 minutes (range 4 - 45) and 11 minutes (range 4 - 36), respectively (P = 0.03). When a multivariate linear regression model was used, EBL for right-sided diverticula was the factor most significantly affecting EBL procedure time. No adverse events were encountered. EBL can be safely and effectively performed by non-expert endoscopists. A right-sided location of diverticula was the factor most significantly affecting EBL procedure time.

  3. Long-term result after rubber band ligation for haemorrhoids.

    PubMed

    Forlini, Antonio; Manzelli, Antonio; Quaresima, Silvia; Forlini, Massimo

    2009-09-01

    Rubber band ligation (RBL) is a well-known and recognised outpatient procedure utilised for the treatment of symptomatic internal haemorrhoids. This paper describes a retrospective study which analyses the short- and long-term results of a personal series of patients. A consecutive group of 206 patients with symptomatic internal second- and third-degree haemorrhoids were treated with RBL as outpatients from 1982 to 1989. Two or three piles were legated in a single session. All patients were systematically visited after 1 month and 1 year. Respectively after 10 and 17 years, all the patients were contacted to obtain a telephone follow-up. The short-term follow-up at 1 month and at 1 year showed that 46% of the patients experienced moderate anal pain for 24 h post procedure. Two patients had severe pain (1%) and were admitted in the hospital to be submitted to an operative haemorrhoidectomy within a few days. Only 2.4% of the patients experienced rectal bleeding after a week, and 20% had a second session of RBL after 1 month. At 1 year follow-up, 90% of the patients with second-degree piles and 75% of patients with third-degree piles reported no residual symptoms. The long-term telephone follow-up at 10 and 17 years collected the history of 138 patients (67%). A group of 69% was asymptomatic, 28% had residual symptoms, and 3% needed further surgery. RBL is a safe and effective treatment for symptomatic internal haemorrhoids. Our long-term follow-up demonstrated good long-term results for internal second- and third-degree haemorrhoids.

  4. High-Efficiency Microwave Power Amplifier

    NASA Technical Reports Server (NTRS)

    Sims, Williams H.

    2005-01-01

    A high-efficiency power amplifier that operates in the S band (frequencies of the order of a few gigahertz) utilizes transistors operating under class-D bias and excitation conditions. Class-D operation has been utilized at lower frequencies, but, until now, has not been exploited in the S band. Nominally, in class D operation, a transistor is switched rapidly between "on" and "off" states so that at any given instant, it sustains either high current or high voltage, but not both at the same time. In the ideal case of zero "on" resistance, infinite "off" resistance, zero inductance and capacitance, and perfect switching, the output signal would be a perfect square wave. Relative to the traditional classes A, B, and C of amplifier operation, class D offers the potential to achieve greater power efficiency. In addition, relative to class-A amplifiers, class-D amplifiers are less likely to go into oscillation. In order to design this amplifier, it was necessary to derive mathematical models of microwave power transistors for incorporation into a larger mathematical model for computational simulation of the operation of a class-D microwave amplifier. The design incorporates state-of-the-art switching techniques applicable only in the microwave frequency range. Another major novel feature is a transmission-line power splitter/combiner designed with the help of phasing techniques to enable an approximation of a square-wave signal (which is inherently a wideband signal) to propagate through what would, if designed in a more traditional manner, behave as a more severely band-limited device (see figure). The amplifier includes an input, a driver, and a final stage. Each stage contains a pair of GaAs-based field-effect transistors biased in class D. The input signal can range from -10 to +10 dBm into a 50-ohm load. The table summarizes the performances of the three stages

  5. Injection- Seeded Optoplasmonic Amplifier in the Visible

    PubMed Central

    Gartia, Manas Ranjan; Seo, Sujin; Kim, Junhwan; Chang, Te-Wei; Bahl, Gaurav; Lu, Meng; Liu, Gang Logan; Eden, J. Gary

    2014-01-01

    A hybrid optoplasmonic amplifier, injection-seeded by an internally-generated Raman signal and operating in the visible (563–675 nm), is proposed and evidence for amplification is presented. Comprising a gain medium tethered to a whispering gallery mode (WGM) resonator with a protein, and a plasmonic surface, the optical system described here selectively amplifies a single (or a few) Raman line(s) produced within the WGM resonator and is well-suited for routing narrowband optical power on-a-chip. Over the past five decades, optical oscillators and amplifiers have typically been based on the buildup of the field from the spontaneous emission background. Doing so limits the temporal coherence of the output, lengthens the time required for the optical field intensity to reach saturation, and often is responsible for complex, multiline spectra. In addition to the spectral control afforded by injection-locking, the effective Q of the amplifier can be specified by the bandwidth of the injected Raman signal. This characteristic contrasts with previous WGM-based lasers and amplifiers for which the Q is determined solely by the WGM resonator. PMID:25156810

  6. High power, high beam quality regenerative amplifier

    DOEpatents

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

    1993-08-24

    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.

  7. High power, high beam quality regenerative amplifier

    DOEpatents

    Hackel, Lloyd A.; Dane, Clifford B.

    1993-01-01

    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.

  8. Plastic optical amplifier using europium complex

    NASA Astrophysics Data System (ADS)

    Oh, Doogie; Song, Namwoong; Kim, Jang-Joo

    2001-04-01

    Potential of polymer optical amplifier doped with europium complex has been analyzed for practical use in visible range. Europium this(2-thenoyltrifluoroacetonate)-1,10- phenanthroline was used as the amplification dopant and PMMA as matrix. Spectroscopic properties of the dopant such as metastable excited state lifetime, simulated emission cross section, and stimulated absorption cross section were obtained using the photoluminescence spectroscopy, UV visible spectrophotometry and time-resolved spectroscopy. Lifetime of 5D0 metastable state is 0.9 ms, which is longer than usual rare earth complex. Its emission cross section is comparable to erbium ions and absorption cross section is 4 orders of magnitude higher than bare rare earth ions. Optical amplifier was fabricated by the dip-coating method. The refractive index profile of the polymer optical amplifier was designed to manifest a single mode structure for the optimization of amplification performance. Amplification characteristics were simulated with respect to pump power, amplifier length, and number density of Eu(TTA)3phen. The simulations showed that optical gains are saturated above some maximum po9int. More than 30 dB optical gain can be achieved with 5 m long amplifier at 300 mW pump power.

  9. Thermal recovery of the NIF amplifiers

    SciTech Connect

    Beullier, J; Bicrel,; Erlandson, A; London, R; Manes, K; Marshall, C; Petty, C; Pierce, R; Smith, L; Sutton, S; Zapata, L

    1998-06-30

    With approximately 99% of the electrical energy supplied to the National Ignition Facility (NIF) appearing as heat in the amplifiers, thermal recovery of the NIF system is a major consideration in the design process. The NIF shot rate is one shot every 8 hours, with a goal of 4 hours between shots. This necessitates that thermal recovery take place in no more than 7 hours, with a goal of 3 hours for the accelerated shot rate. Residual optical distortions, which restrict the shot rate, are grouped into two discrete categories: (1) distortions associated with residual temperature gradients in the laser slabs, and (2) distortions associated with buoyantly driven convective currents in the amplifier cavity and beam-tube regions. Thermal recovery of the amplifiers is achieved by cooling the flashlamps and blastshields with a turbulent gas flow. The cooled blastshields then serve as a cold boundary to radiatively extract the residual heat deposited in the slabs and edge claddings. Advanced concepts, such as the use of slightly chilled gas to accelerate some aspects of recovery, are addressed. To quantify recovery rates of the amplifiers, experiments and numerical models are used to measure and calculate the temperatures and optical distortions in NIF-like amplifier elements. The calculation results are benchmarked against AMLAB temperature measurements, thus allowing a quantitative prediction of NIF thermal recovery. These results indicate that the NIF requirement of 7 hour thermal recovery can be achieved with chilled temperature cooling gas.

  10. Improved Grid-Array Millimeter-Wave Amplifier

    NASA Technical Reports Server (NTRS)

    Rosenberg, James J.; Rutledge, David B.; Smith, R. Peter; Weikle, Robert

    1993-01-01

    Improved grid-array amplifiers operating at millimeter and submillimeter wavelengths developed for use in communications and radar. Feedback suppressed by making input polarizations orthogonal to output polarizations. Amplifier made to oscillate by introducing some feedback. Several grid-array amplifiers concatenated to form high-gain beam-amplifying unit.

  11. Method to amplify variable sequences without imposing primer sequences

    DOEpatents

    Bradbury, Andrew M.; Zeytun, Ahmet

    2006-11-14

    The present invention provides methods of amplifying target sequences without including regions flanking the target sequence in the amplified product or imposing amplification primer sequences on the amplified product. Also provided are methods of preparing a library from such amplified target sequences.

  12. Complement component C5 deficiency reduces edema formation in murine ligation-induced acute pancreatitis.

    PubMed

    Merriam, L T; Webster, C; Joehl, R J

    1997-01-01

    The complement cascade is activated in humans and animals with acute pancreatitis. Activation of complement component C5 liberates C5a, C5a-desarg, and terminal complement complexes (TCCs) that increase capillary permeability, edema, and leukocyte chemotaxis at injured sites. Complement activation plays a major role in pathogenesis of capillary leak and edema formation in severe acute pancreatitis; however, the contribution of C5 (C5a/C5a-desarg, TCCs) has not been defined. Using He gene mutant mice lacking circulating C5, the role of C5 in ligation-induced acute pancreatitis was evaluated. We performed the following experiments: C5-sufficient (Hc1/Hc1) and C5-deficient (Hc0/Hc0) mice had bile and pancreatic ducts ligated. Sham-operated mice had ducts dissected but not ligated. Mice were killed at 4, 8, and 24 hr after bilepancreatic duct ligation. Serologic and morphologic evidences of acute pancreatitis were evaluated. Pancreatic edema was assessed using analysis of pancreatic water content, histologic edema score, and determination of wet weight ratio. After 4, 8, and 24 hr of bile-pancreatic duct ligation, hyperamylasemia and histologic changes of acute pancreatitis were observed in both C5-deficient and C5-sufficient mice. Edema developed in all mice with acute pancreatitis. However, when compared to C5-sufficient mice, mice deficient in C5 developed significantly less pancreatic edema at both 8 and 24 hr of bile-pancreatic duct ligation. This difference was not observed 4 hr after induction of acute pancreatitis. We conclude that C5 contributes to edema formation in murine ligation-induced acute pancreatitis. The presence of an early C5-independent phase, in conjunction with the observation of significant edema in mice deficient in C5, suggests there are other mediators of edema formation in this acute pancreatitis model.

  13. Frictional evaluations of dental typodont models using four self-ligating designs and a conventional design.

    PubMed

    Henao, Sandra P; Kusy, Robert P

    2005-01-01

    Abstract: After a previous study using typodonts and three standardized archwire (AW) sizes, the frictional evaluations of four self-ligating brackets were directed toward the optimal AW-bracket system. Four participating manufacturers suggested three AWs, which were a representation of the three stages of orthodontic treatment, to be coupled with their respective self-ligating design. Four replicated typodont models were mounted with a self-ligating design, and a fifth model was mounted with a conventional design that served as a control. The first experiment evaluated the manufacturer-suggested AWs against the respective self-ligating design. Because no third-stage AWs could engage their respective designs, a second experiment was implemented to gain more detailed analyses of the designs. This experiment included any successful manufacturer-suggested AWs from the first experiment against the four self-ligating designs and the control design. All self-ligating designs performed with the efficiency and reproducibility associated with expectations. Specifically, self-ligation outperformed the conventional brackets when coupled with up to 0.020- x 0.020-inch wires. The clearance of the various AW sizes and alloys changed with malocclusion. Furthermore, the parameter that best correlated with drawing forces was the bending stiffness of the AW, which was directly associated with the nominal dimension of each wire. The best AW-bracket system can be selected, when taking into account the stiffness (elastic modulus and size of the AW) along with the amount of malocclusion present, once the treatment plan is determined.

  14. Amitriptyline and phenytoin prevents memory deficit in sciatic nerve ligation model of neuropathic pain.

    PubMed

    Abdulmajeed, Wahab Imam; Ibrahim, Ridwan Babatunde; Ishola, Azeez Olakunle; Balogun, Wasiu Gbolahan; Cobham, Ansa Emmanuel; Amin, Abdulbasit

    2016-03-01

    Phenytoin and amitriptyline are often reported to attenuate pain in chronic conditions. Information on their ability to ameliorate cognitive impairment associated with neuropathic pain remains unclear due to mixed results from studies. This study investigated the effects of phenytoin and amitriptyline on memory deficit associated with neuropathic pain. Twenty-eight adult male Wistar rats were randomly divided into four groups: A, B, C, and D (n=7). Groups A, B, C, and D served as sham control, sciatic nerve ligated untreated, sciatic nerve ligated receiving amitriptyline (5 mg/kg), and sciatic nerve ligated receiving phenytoin (10 mg/kg) respectively. Treatments lasted for 14 days, after which both 'Y' maze and novel object recognition test (NOR) were performed. On the last day of treatment, the animals were anesthetized and their brain excised, and the prefrontal cortices and sciatic nerve were processed histologically using hematoxylin and eosin. There was memory impairment in the sciatic nerve ligated untreated group which was statistically significant (p<0.05) when compared to the phenytoin-treated, amitriptyline-treated, and sham control groups using the 'Y' maze and NOR tests. Histological quantification showed that the prefrontal cortices of the ligated animals showed increased neural population in comparison to normal control. These increases were significantly marked in the untreated ligated group. Sciatic nerve of untreated ligated group showed high demyelination and axonal degeneration which was ameliorated in the treated animals. The administration of amitriptyline and phenytoin can ameliorate neuronal injury, demyelination, and memory impairment associated with neuropathic pain in Wistar rats.

  15. The effect of lumbar sympathectomy on increased tactile sensitivity in spinal nerve ligated rats.

    PubMed

    Lee, D H; Katner, J; Iyengar, S; Lodge, D

    2001-02-02

    The aim of this study was to investigate the reason for the contradictory results following surgical sympathectomy on increased tactile sensitivity in spinal nerve ligated rats. For this purpose, firstly the results of L5 spinal nerve ligation alone and both L5 and L6 (L5/6) spinal nerve ligation were compared in Sprague-Dawley rats. Secondly, the difference in tactile sensitivity between the plantar surface (the middle glabrous area on the foot pads of the hind paw) and on the toe (the proximal half of the third and fourth toe of the hind paw) after the spinal nerve injury was studied. Third, we divided the L5 spinal nerve ligated rats into two groups, (i.e. low and high threshold groups) based on the degree of tactile sensitivity and investigated the effect of surgical lumbar sympathectomy (L2-L5) on tactile sensitivity in both the plantar and toe areas. The results show that the tactile sensitivities of L5 spinal nerve ligated rats and L5/6 spinal nerve ligated rats were not different. However, tactile sensitivities of the plantar surface were less than those of toe area suggesting that the response from toe is a better indicator of neuropathic pain. Surgical sympathectomy reduced the response from only the toe area and only in the low threshold group. These results suggest that the reason for the contradictory results of surgical sympathectomy in spinal nerve ligation models is, at least in part, the difference in the degree of mechanical allodynia in each study.

  16. Risk of pulmonary embolism with repair or ligation of major venous injury following penetrating trauma.

    PubMed

    Allen, Casey J; Hsu, Albert; Murray, Clark R; Meizoso, Jonathan P; Ray, Juliet J; Schulman, Carl I; Livingstone, Alan S; Lineen, Edward B; Ginzburg, Enrique; Namias, Nicholas; Proctor, Kenneth G

    2015-03-01

    There are many benefits of repair over ligation of major venous injuries (MVIs) following penetrating trauma, but the risk of pulmonary embolism (PE) is not well defined. We hypothesized that rates of PE are comparable between repair and ligation of MVI. All penetrating trauma patients with MVI requiring an operation from 2003 to 2012 (n = 158) were retrospectively reviewed. Propensity scores were based on a logistic regression model using patient and injury characteristics. A 1:1 fixed ratio nearest neighbor matching was performed to compare outcomes of the repair and ligation cohorts. Data are reported as mean ± SD if parametric, or median (interquartile range) if not, and compared using a t test, Mann-Whitney U-test, χ2, or Fisher's exact test, as appropriate. The population was 89% male, age 32 ± 12 years, 74% gunshot wound, Injury Severity Score of 19 ± 13, length of stay of 9 (18) days, 3.8% PE, and a mortality of 21.5%. Repair was performed in 37% (n = 59), ligation was performed in 60% (n = 94), and 3% required both. With ligation versus repair, ligation patients were generally more critically injured; 48-hour survival was 78% versus 93% (p = 0.0083), initial Glasgow Coma Scale (GCS) score was 12 ± 5 versus 14 ± 3 (p = 0.003), initial base excess was -9 ± 8 versus -5 ± 5 mEq/L (p = 0.003), more packed red blood cells were transfused (12 (14) U vs. 9 (12) U; p = 0.032), and major arterial injury was more likely (86% vs. 42%, p < 0.001), but the PE rate was identical (5.9%) in propensity-matched cohorts. In those who developed a PE, all were receiving standard thromboprophylaxis. Following penetrating trauma, the risk of PE between repair and ligation of MVI is comparable. Epidemiologic study, level III.

  17. Influence of coronary architecture on the variability in myocardial infarction induced by coronary ligation in rats.

    PubMed

    Kainuma, Satoshi; Miyagawa, Shigeru; Fukushima, Satsuki; Tsuchimochi, Hirotsugu; Sonobe, Takashi; Fujii, Yutaka; Pearson, James T; Saito, Atsuhiro; Harada, Akima; Toda, Koichi; Shirai, Mikiyasu; Sawa, Yoshiki

    2017-01-01

    It has been shown that the size of myocardial infarction in rats created by coronary ligation technique is not uniform, varying from 4% to 65%. We hypothesized that infarct size variability induced by coronary artery ligation might be caused by coronary artery branching pattern. Coronary artery angiography was performed in 50 normal Lewis rats and in chronic myocardial infarction models in which coronary artery was ligated immediately below the left atrial appendage or 2mm distal to the left atrial appendage (n = 25 for each), followed by histological analysis. Unlike the human, the rats had a single major septal artery arising from the proximal part of the left coronary artery (n = 30) or right coronary artery (n = 20). There were three branching patterns of left circumflex artery (LCX): 33 (66%) had LCX branching peripherally from a long left main coronary artery (LMCA), while the remainder 17 (34%) had the LCX branching from the proximal part of the septal artery or a short LMCA. The rats with distal coronary ligation presented myocardial infarction localized to an anterior territory irrespective of LCX branching pattern. In the rats with proximal coronary ligation, 64% (n = 16) had broad myocardial infarction involving the anterior and lateral territories, while the remainder (36%, n = 9) had myocardial infarction localized to an anterior territory with the intact LCX arising proximally from a short LMCA. The interventricular septum was spared from infarction in all rats because of its anatomical location. Infarct size variations were caused not only by ligation site but also by varying LCX branching patterns. There are potential risks to create different sizes of myocardial infarction, particularly when targeting a broad range of myocardial infarction. The territory of the septal artery always appears to be spared from myocardial infarction induced by the coronary ligation technique.

  18. Effects of ligation of lateral intermuscular septum perforating vessels on blood supply to the femur.

    PubMed

    Grob, K; Manestar, M; Lang, A; Ackland, T; Gilbey, H; Kuster, M S

    2015-12-01

    With a subvastus approach to the femur, the vessels that perforate the lateral intermuscular septum (LISP-vessels) must be ligated. The effect on the blood supply to the femur remains unclear. The purpose of the current study was to investigate the effect of ligation of the LISP-Vessels on the blood supply and to examine the anatomy of the LISP-vessels and the anastomoses around the femur. In six human cadavers the LISP vessels were ligated by a lateral subvastus approach on one side. The contralateral side served as control group. After bilateral injection of different coloured silicon dyes into the lateral and medial circumflex femoral artery (green), deep femoral artery (red) and the superficial femoral artery (blue) dissection was performed bilaterally. The arterial perfusion on both sides was compared and the anatomy of the LISP vessels studied. The medullary perfusion of the femur was not altered by the ligation of the LISP vessels. It did also not lead to a decrease in periosteal vessel filling. The LISP vessels were shown to be a part of a complex and rich anastomotic network and play an important role in the perfusion of the femur and quadriceps muscle group. The ligature could be compensated for by this anastomotic network. Branches to the periosteum separate from the LISP vessels immediately after perforating the lateral intermuscular septum. The linea aspera turned out to be an important area for the femoral blood supply. Exposure of the femur through a lateral subvastus approach with ligation of LISP vessels causes a certain degree of soft tissue trauma. However, by using a gentle surgical technique the periostal perfusion of the femur can be preserved by a potent anastomotic network after ligation of the LISP vessels if they are not ligated to close to the lateral intermuscular septum and the linea aspera is not unnecessarily exposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Advances in ligase chain reaction and ligation-based amplifications for genotyping assays: Detection and applications.

    PubMed

    Gibriel, Abdullah A; Adel, Ola

    2017-07-01

    Genetic variants have been reported to cause several genetic diseases. Various genotyping assays have been developed for diagnostic and screening purposes but with certain limitations in sensitivity, specificity, cost effectiveness and/or time savings. Since the discovery of ligase chain reaction (LCR) in the late nineties, it became one of the most favored platforms for detecting these variants and also for genotyping low abundant contaminants. Recent and powerful modifications with the integration of various detection strategies such as electrochemical and magnetic biosensors, nanoparticles (NPs), quantum dots, quartz crystal and leaky surface acoustic surface biosensors, DNAzyme, rolling circle amplification (RCA), strand displacement amplification (SDA), surface enhanced raman scattering (SERS), chemiluminescence and fluorescence resonance energy transfer have been introduced to both LCR and ligation based amplifications to enable high-throughput and inexpensive multiplex genotyping with improved robustness, simplicity, sensitivity and specificity. In this article, classical and up to date modifications in LCR and ligation based amplifications are critically evaluated and compared with emphasis on points of strength and weakness, sensitivity, cost, running time, equipment needed, applications and multiplexing potential. Versatile genotyping applications such as genetic diseases detection, bacterial and viral pathogens detection are also detailed. Ligation based gold NPs biosensor, ligation based RCA and ligation mediated SDA assays enhanced detection limit tremendously with a discrimination power approaching 1.5aM, 2aM and 0.1fM respectively. MLPA (multiplexed ligation dependent probe amplification) and SNPlex assays have been commercialized for multiplex detection of at least 48 SNPs at a time. MOL-PCR (multiplex oligonucleotide ligation) has high-throughput capability with multiplex detection of 50 SNPs/well in a 96 well plate. Ligase detection reaction (LDR

  20. Remote Perturbations in Tertiary Contacts Trigger Ligation of Lysine to the Heme Iron in Cytochrome c.

    PubMed

    Gu, Jie; Shin, Dong-Woo; Pletneva, Ekaterina V

    2017-06-13

    Perturbations in protein structure define the mechanism of allosteric regulation and biological information transfer. In cytochrome c (cyt c), ligation of Met80 to the heme iron is critical for the protein's electron-transfer (ET) function in oxidative phosphorylation and for suppressing its peroxidase activity in apoptosis. The hard base Lys is a better match for the hard ferric iron than the soft base Met is, suggesting the key role of the protein scaffold in favoring Met ligation. To probe the role of the protein structure in the maintenance of Met ligation, mutations T49V and Y67R/M80A were designed to disrupt hydrogen bonding and packing of the heme coordination loop, respectively. Electronic absorption, nuclear magnetic resonance, and electron paramagnetic resonance spectra reveal that ferric forms of both variants are Lys-ligated at neutral pH. A minor change in the tertiary contacts in T49V, away from the heme coordination loop, appears to be sufficient to execute a change in ligation, suggesting a cross-talk between the different regions of the protein structure and a possibility of built-in conformational switches in cyt c. Analyses of thermodynamic stability, kinetics of Lys binding and dissociation, and the pH-dependent changes in ligation provide a detailed characterization of the Lys coordination in these variants and relate these properties to the extent of structural perturbations. The findings emphasize the importance of the hydrogen-bonding network in controlling ligation of the native Met80 to the heme iron.

  1. EARLY MARKERS OF REGENERATION FOLLOWING DUCTAL LIGATION IN THE RAT SUBMANDIBULAR GLAND

    PubMed Central

    Cotroneo, Emanuele; Proctor, Gordon B.; Paterson, Katherine L.; Carpenter, Guy H.

    2008-01-01

    Rat submandibular glands can recover their function and secretory protein content following ductal ligation-induced atrophy. Morphological studies have established that following ligation, deligation of the gland regenerates new salivary gland tissue. However, little is know about changes happening during early regeneration following intra-oral duct ligation, which does not damage the parasympathetic nerves. Gland that had been 2 weeks ligated or 2 weeks ligated + 3 days deligation glands were compared. Tissue was prepared for histological, immunohistochemical (SMG-B and Ki 67) and immunocytochemical analyses (smooth muscle actin, aquaporin 5). H&E staining of deligated glands showed some acini have regained their cytoplasmic volume; moreover, the loss of AB/PAS staining from the lumen of ducts suggested successful deligation. The deligated gland was characterized by atypical acinar-ductal branched structures, which were less frequent in the ligated gland and rarely seen in normal unoperated tissue. Myoepithelial cells were also investigated since changes in their morphology reflected changes in the acini morphology not readily detected by conventional staining. Actin staining revealed the presence of some shrunken acini in the atrophic tissue whereas they had regained their normal morphology in the deligated gland suggesting the acini were recovering. Some acini during deligation regained aquaporin 5 expression which was decreased during atrophy. Furthermore SMG-B protein, located in the pro-acinar cell during gland development and usually located in the intercalated duct cells in the adult, has been detected in the newly formed acini of the deligated gland. This study suggests that morphological markers of regeneration are apparent after just 3 days following ligation removal. PMID:18335244

  2. Detection of metal ions (Cu2+, Hg2+) and cocaine by using ligation DNAzyme machinery.

    PubMed

    Wang, Fuan; Orbach, Ron; Willner, Itamar

    2012-12-07

    The Cu(2+)-dependent ligation DNAzyme is implemented as a biocatalyst for the colorimetric or chemiluminescence detection of Cu(2+) ions, Hg(2+) ions, or cocaine. These sensing platforms are based on the structural tailoring of the sequence of the Cu(2+)-dependent ligation DNAzyme for specific analytes. The tethering of a subunit of the hemin/G-quadruplex DNAzyme to the ligation DNAzyme sequence, and the incorporation of an imidazole-functionalized nucleic-acid sequence, which acts as a co-substrate for the ligation DNAzyme that is tethered to the complementary hemin/G-quadruplex subunit. In the presence of different analytes, Cu(2+) ions, Hg(2+) ions, or cocaine, the pretailored Cu(2+)-dependent ligation DNAzyme sequence stimulates the respective ligation process by combining the imidazole-functionalized co-substrate with the ligation DNAzyme sequence. These reactions lead to the self-assembly of stable hemin/G-quadruplex DNAzyme nanostructures that enable the colorimetric analysis of the substrate through the DNAzyme-catalyzed oxidation of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), ABTS(2-), by H(2)O(2) into the colored product ABTS(·-), or the chemiluminescence detection of the substrate through the DNAzyme-catalyzed oxidation of luminol by H(2)O(2). The detection limits for the sensing of Cu(2+) ions, Hg(2+) ions, and cocaine correspond to 1 nM, 10 nM and 2.5 μM, respectively. These different sensing platforms also reveal impressive selectivities. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Implementation of a nondeterministic optical noiseless amplifier.

    PubMed

    Ferreyrol, Franck; Barbieri, Marco; Blandino, Rémi; Fossier, Simon; Tualle-Brouri, Rosa; Grangier, Philippe

    2010-03-26

    Quantum mechanics imposes that any amplifier that works independently on the phase of the input signal has to introduce some excess noise. The impossibility of such a noiseless amplifier is rooted in the unitarity and linearity of quantum evolution. A possible way to circumvent this limitation is to interrupt such evolution via a measurement, providing a random outcome able to herald a successful-and noiseless-amplification event. Here we show a successful realization of such an approach; we perform a full characterization of an amplified coherent state using quantum homodyne tomography, and observe a strong heralded amplification, with about a 6 dB gain and a noise level significantly smaller than the minimal allowed for any ordinary phase-independent device.

  4. Ultraflexible organic amplifier with biocompatible gel electrodes.

    PubMed

    Sekitani, Tsuyoshi; Yokota, Tomoyuki; Kuribara, Kazunori; Kaltenbrunner, Martin; Fukushima, Takanori; Inoue, Yusuke; Sekino, Masaki; Isoyama, Takashi; Abe, Yusuke; Onodera, Hiroshi; Someya, Takao

    2016-04-29

    In vivo electronic monitoring systems are promising technology to obtain biosignals with high spatiotemporal resolution and sensitivity. Here we demonstrate the fabrication of a biocompatible highly conductive gel composite comprising multi-walled carbon nanotube-dispersed sheet with an aqueous hydrogel. This gel composite exhibits admittance of 100 mS cm(-2) and maintains high admittance even in a low-frequency range. On implantation into a living hypodermal tissue for 4 weeks, it showed a small foreign-body reaction compared with widely used metal electrodes. Capitalizing on the multi-functional gel composite, we fabricated an ultrathin and mechanically flexible organic active matrix amplifier on a 1.2-μm-thick polyethylene-naphthalate film to amplify (amplification factor: ∼200) weak biosignals. The composite was integrated to the amplifier to realize a direct lead epicardial electrocardiography that is easily spread over an uneven heart tissue.

  5. Ultraflexible organic amplifier with biocompatible gel electrodes

    PubMed Central

    Sekitani, Tsuyoshi; Yokota, Tomoyuki; Kuribara, Kazunori; Kaltenbrunner, Martin; Fukushima, Takanori; Inoue, Yusuke; Sekino, Masaki; Isoyama, Takashi; Abe, Yusuke; Onodera, Hiroshi; Someya, Takao

    2016-01-01

    In vivo electronic monitoring systems are promising technology to obtain biosignals with high spatiotemporal resolution and sensitivity. Here we demonstrate the fabrication of a biocompatible highly conductive gel composite comprising multi-walled carbon nanotube-dispersed sheet with an aqueous hydrogel. This gel composite exhibits admittance of 100 mS cm−2 and maintains high admittance even in a low-frequency range. On implantation into a living hypodermal tissue for 4 weeks, it showed a small foreign-body reaction compared with widely used metal electrodes. Capitalizing on the multi-functional gel composite, we fabricated an ultrathin and mechanically flexible organic active matrix amplifier on a 1.2-μm-thick polyethylene-naphthalate film to amplify (amplification factor: ∼200) weak biosignals. The composite was integrated to the amplifier to realize a direct lead epicardial electrocardiography that is easily spread over an uneven heart tissue. PMID:27125910

  6. Single mode terahertz quantum cascade amplifier

    SciTech Connect

    Ren, Y. Wallis, R.; Shah, Y. D.; Jessop, D. S.; Degl'Innocenti, R.; Klimont, A.; Kamboj, V.; Beere, H. E.; Ritchie, D. A.

    2014-10-06

    A terahertz (THz) optical amplifier based on a 2.9 THz quantum cascade laser (QCL) structure has been demonstrated. By depositing an antireflective coating on the QCL facet, the laser mirror losses are enhanced to fully suppress the lasing action, creating a THz quantum cascade (QC) amplifier. Terahertz radiation amplification has been obtained, by coupling a separate multi-mode THz QCL of the same active region design to the QC amplifier. A bare cavity gain is achieved and shows excellent agreement with the lasing spectrum from the original QCL without the antireflective coating. Furthermore, a maximum optical gain of ∼30 dB with single-mode radiation output is demonstrated.

  7. Ultrashort pulse amplification in cryogenically cooled amplifiers

    DOEpatents

    Backus, Sterling J.; Kapteyn, Henry C.; Murnane, Margaret Mary

    2004-10-12

    A laser amplifier system amplifies pulses in a single "stage" from .about.10.sup.-9 joules to more than 10.sup.-3 joules, with average power of 1-10 watts, and beam quality M.sup.2 <2. The laser medium is cooled substantially below room temperature, as a means to improve the optical and thermal characteristics of the medium. This is done with the medium inside a sealed, evacuated or purged cell to avoid moisture or other materials condensing on the surface. A "seed" pulse from a separate laser is passed through the laser medium, one or more times, in any of a variety of configurations including single-pass, multiple-pass, and regenerative amplifier configurations.

  8. Modulation instability in high power laser amplifiers.

    PubMed

    Rubenchik, Alexander M; Turitsyn, Sergey K; Fedoruk, Michail P

    2010-01-18

    The modulation instability (MI) is one of the main factors responsible for the degradation of beam quality in high-power laser systems. The so-called B-integral restriction is commonly used as the criteria for MI control in passive optics devices. For amplifiers the adiabatic model, assuming locally the Bespalov-Talanov expression for MI growth, is commonly used to estimate the destructive impact of the instability. We present here the exact solution of MI development in amplifiers. We determine the parameters which control the effect of MI in amplifiers and calculate the MI growth rate as a function of those parameters. The safety range of operational parameters is presented. The results of the exact calculations are compared with the adiabatic model, and the range of validity of the latest is determined. We demonstrate that for practical situations the adiabatic approximation noticeably overestimates MI. The additional margin of laser system design is quantified.

  9. High Bandwidth Differential Amplifier for Shock Experiments

    SciTech Connect

    Ross, P. W., Tran, V., Chau, R.

    2012-04-30

    We developed a high bandwidth differential amplifier for gas gun shock experiments/applications. The circuit has a bandwidth > 1 GHz, and is capable of measuring signals of ≤1.5 V with a common mode rejection of 250 V. Conductivity measurements of gas gun targets are measured by flowing high currents through the targets. The voltage is measured across the target using a technique similar to a four-point probe. Because of the design of the current source and load, the target voltage is approximately 250 V relative to ground. Since the expected voltage change in the target is < 1 V, the differential amplifier must have a large common mode rejection. High pass filters suppress internal ringing of operational amplifiers. Results of bench tests are shown.

  10. Noise in chi (3) and photorefractive amplifiers

    NASA Astrophysics Data System (ADS)

    Sternklar, Shmuel; Glick, Yaakov

    1995-12-01

    A comparison of the noise characteristics of chi (3) and photorefractive coherent amplifiers reveals basic differences in their dependence on operating parameters. Unlike all types of chi (3) amplifiers, which are shown to have a well-defined optimum working point in the region of the self-stimulated scattering threshold, the photorefractive amplifier can be made increasingly quieter by lowering the pump power. This is demonstrated by use of highly doped Co:BaTiO3 in a tight-focus reflection grating geometry. It is shown that scattering from inhomogeneities in the crystal is the major limiting noise source and is significantly higher than predictions resulting from fundamental considerations such as random space-charge noise. An extremely high small-signal gain of 107 was measured with this crystal and geometry. To our knowledge this is the highest photorefractive gain reported to date.

  11. Ultraflexible organic amplifier with biocompatible gel electrodes

    NASA Astrophysics Data System (ADS)

    Sekitani, Tsuyoshi; Yokota, Tomoyuki; Kuribara, Kazunori; Kaltenbrunner, Martin; Fukushima, Takanori; Inoue, Yusuke; Sekino, Masaki; Isoyama, Takashi; Abe, Yusuke; Onodera, Hiroshi; Someya, Takao

    2016-04-01

    In vivo electronic monitoring systems are promising technology to obtain biosignals with high spatiotemporal resolution and sensitivity. Here we demonstrate the fabrication of a biocompatible highly conductive gel composite comprising multi-walled carbon nanotube-dispersed sheet with an aqueous hydrogel. This gel composite exhibits admittance of 100 mS cm-2 and maintains high admittance even in a low-frequency range. On implantation into a living hypodermal tissue for 4 weeks, it showed a small foreign-body reaction compared with widely used metal electrodes. Capitalizing on the multi-functional gel composite, we fabricated an ultrathin and mechanically flexible organic active matrix amplifier on a 1.2-μm-thick polyethylene-naphthalate film to amplify (amplification factor: ~200) weak biosignals. The composite was integrated to the amplifier to realize a direct lead epicardial electrocardiography that is easily spread over an uneven heart tissue.

  12. Short pulse free electron laser amplifier

    DOEpatents

    Schlitt, Leland G.; Szoke, Abraham

    1985-01-01

    Method and apparatus for amplification of a laser pulse in a free electron laser amplifier where the laser pulse duration may be a small fraction of the electron beam pulse duration used for amplification. An electron beam pulse is passed through a first wiggler magnet and a short laser pulse to be amplified is passed through the same wiggler so that only the energy of the last fraction, f, (f<1) of the electron beam pulse is consumed in amplifying the laser pulse. After suitable delay of the electron beam, the process is repeated in a second wiggler magnet, a third, . . . , where substantially the same fraction f of the remainder of the electron beam pulse is consumed in amplification of the given short laser pulse in each wiggler magnet region until the useful electron beam energy is substantially completely consumed by amplification of the laser pulse.

  13. Design and analysis of a high efficiency linear power amplifier

    NASA Astrophysics Data System (ADS)

    Liu, Sucheng; Zhou, Luowei; Liu, Xiaodong; Lu, Weiguo

    2011-10-01

    A high efficiency linear power amplifier is introduced based on the idea of Switch-Linear Hybrid (SLH) power conversion. The SLH power amplifier developed from the conventional class B power amplifier, while the class B configuration power unit in the SLH power amplifier is fed by a dynamic switching power supply, not the usual constant DC power supply. Thus, the efficiency of the class B configuration power unit in SLH power amplifier can be greatly improved. By combining linear power amplifier with switching power supply, the SLH power amplifier has synthetic performance of high fidelity, high efficiency and excellent dynamic characteristics. In this article, analysis of SLH power amplifier is performed, especially focusing on its linear power unit which is the core of SLH power amplifier. Design considerations are also presented parallel with the analysis. Both the theoretical analysis and experimental results verify the validity of SLH power amplifier.

  14. Class E power amplifiers for wireless communications

    NASA Astrophysics Data System (ADS)

    Sowlati Hashjani, Tirdad

    In this thesis, the use of Class E power amplifiers for digital wireless communication applications is presented for the first time. A linear transmitter design using Class E amplifier is proposed for the North American Digital Cellular Standard. In this architecture, a phase correcting feedback loop is used to cancel the AM-PM distortion in Class E power amplifier. Several low voltage Class E power amplifiers, and the phase correcting feedback loop are designed and implemented in a commercially available 0.8 mum GaAs MESFET process. A fully integrated Class E power module operating at 835 MHz is presented. The power module consists of a Class F driver stage and a Class E power amplifier, and delivers 250 mW to the standard 50 Omega load with a power added efficiency of 51%. The design and implementation of a hybrid Class E power module operating at 835 MHz is also discussed. In this design, the output matching network is implemented on an alumina substrate, and has a lower power dissipation than its GaAs counterpart. The power module delivers 443 mW to the 50 Omega load with a power added efficiency of 67%. A 1.8 GHz fully integrated Class E power module is also presented. In this case, the power module delivers 200 mW of power to the 50 Omega load with a power added efficiency of 57%. The design and implementation of the phase correcting feedback loop, which consists of a limiting amplifier, a phase detector and two phase shifters, are discussed. The phase correcting feedback loop is used to linearize the 835 MHz Class E hybrid power module. With a loop gain of 20, the maximum phase distortion in the power module was reduced from 30sp° to 4sp° and the total power added efficiency was 65%.

  15. Transverse intensity transformation by laser amplifiers

    NASA Astrophysics Data System (ADS)

    Litvin, Igor A.; King, Gary; Collett, Oliver J. P.; Strauss, Hencharl J.

    2015-03-01

    Lasers beams with a specific intensity profile such as super-Gaussian, Airy or Dougnut-like are desirable in many applications such as laser materials processing, medicine and communications. We propose a new technique for laser beam shaping by amplifying a beam in an end-pumped bulk amplifier that is pumped with a beam that has a modified intensity profile. Advantages of this method are that it is relatively easy to implement, has the ability to reshape multimode beams and is naturally suited to high power/energy beams. Both three and four level gain materials can be used as amplifier media. However, a big advantage of using three level materials is their ability to attenuate of the seed beam, which enhances the contrast of the shaping. We first developed a numerical method to obtain the required pump intensity for an arbitrary beam transformation. This method was subsequently experimentally verified using a three level system. The output of a 2.07 μm seed laser was amplified in a Ho:YLF bulk amplifier which was being pumped by a 1.89 μm Tm:YLF laser which had roughly a TEM10 Hermit Gaussian intensity profile. The seed beam was amplified from 0.3 W to 0.55 W at the full pump power of 35 W. More importantly, the beam profile in one transverse direction was significantly shaped from Gaussian to roughly flat-top, as the model predicted. The concept has therefore been shown to be viable and can be used to optimise the beam profile for a wide range of applications.

  16. The effect of ligation of cauda epididymidis and vasectomy on testicular function in the adult gerbil (Meriones hurrianae).

    PubMed

    Dixit, V P; Lohiya, N K; Arya, M

    1975-08-01

    1. The effects of ligation of caput, cauda epididymides and vasectomy were studied in adult gerbils. 2. The operations were performed unilaterally, the testis and epididymides on the contralateral side serving as controls. 3. Ligation of cauda epididymides decrease testicular weight, whereas caput ligation did not change the testis weight. Accessory sex glands were reduced in size. 4. Ligation caused a drastic degeneration of the spermatogenic cells. There was a complete disruption of testicular function. Leydig cell hypertrophy was conspicuous. Caput and cauda ligation led to degenerative changes in the epididymides. Epididymal epithelium was regressed and the lumen was devoid of spermatozoa. 5. Caput and cauda ligation inhibited the synthesis of RNA, protein and sialic acid in testis and epididymides and depleted the fructose concentration in the seminal vesicle. 6. Vasectomy did not cause any alteration in sperm production during the 8 week period on the lighted side. The cytology and the biochemistry of the testis and epididymides appeared to be normal.

  17. Beyond nonlinear saturation of backward Raman amplifiers

    SciTech Connect

    Barth, Ido; Toroker, Zeev; Balakin, Alexey A.; Fisch, Nathaniel J.

    2016-06-27

    Backward Raman amplification is limited by relativistic nonlinear dephasing resulting in saturation of the leading spike of the amplified pulse. We employed pump detuning in order to mitigate the relativistic phase mismatch and to overcome the associated saturation. In an amplified pulse can then be reshaped into a monospike pulse with little precursory power ahead of it, with the maximum intensity increasing by a factor of two. Finally, this detuning can be employed advantageously both in regimes where the group velocity dispersion is unimportant and where the dispersion is important but small.

  18. Implementation of Digital Lock-in Amplifier

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    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.

  19. Master-Oscillator/Power-Amplifier Laser System

    NASA Technical Reports Server (NTRS)

    Yu, Anthony W.; Krainak, Michael A.; Unger, Glenn L.

    1994-01-01

    Master-oscillator/power-amplifier (MOPA) laser system operates in continuous-wave mode or in amplitude-modulation (e.g., pulse) mode by modulation of oscillator current. Power amplifier is laser-diode-pumped neodymium:yttrium lithium fluoride (Nd:YLF) laser; oscillator is laser diode. Offers relatively high efficiency and power. Because drive current to oscillator modulated, external electro-optical modulator not needed. Potential uses include free-space optical communications, coded laser ranging, and generation of high-power, mode-locked pulses.

  20. Master-Oscillator/Power-Amplifier Laser System

    NASA Technical Reports Server (NTRS)

    Yu, Anthony W.; Krainak, Michael A.; Unger, Glenn L.

    1994-01-01

    Master-oscillator/power-amplifier (MOPA) laser system operates in continuous-wave mode or in amplitude-modulation (e.g., pulse) mode by modulation of oscillator current. Power amplifier is laser-diode-pumped neodymium:yttrium lithium fluoride (Nd:YLF) laser; oscillator is laser diode. Offers relatively high efficiency and power. Because drive current to oscillator modulated, external electro-optical modulator not needed. Potential uses include free-space optical communications, coded laser ranging, and generation of high-power, mode-locked pulses.

  1. Beyond nonlinear saturation of backward Raman amplifiers

    DOE PAGES

    Barth, Ido; Toroker, Zeev; Balakin, Alexey A.; ...

    2016-06-27

    Backward Raman amplification is limited by relativistic nonlinear dephasing resulting in saturation of the leading spike of the amplified pulse. We employed pump detuning in order to mitigate the relativistic phase mismatch and to overcome the associated saturation. In an amplified pulse can then be reshaped into a monospike pulse with little precursory power ahead of it, with the maximum intensity increasing by a factor of two. Finally, this detuning can be employed advantageously both in regimes where the group velocity dispersion is unimportant and where the dispersion is important but small.

  2. Transportable setup for amplifier phase fidelity measurements

    NASA Astrophysics Data System (ADS)

    Tröbs, M.; Bogan, C.; Barke, S.; Kühn, G.; Reiche, J.; Heinzel, G.; Danzmann, K.

    2015-05-01

    One possible laser source for the Laser Interferometer Space Antenna (LISA) consists of an Ytterbium-doped fiber amplifier originally developed for inter-satellite communication, seeded by the laser used for the technology demonstrator mission LISA Pathfinder. LISA needs to transmit clock information between its three spacecraft to correct for phase noise between the clocks on the individual spacecraft. For this purpose phase modulation sidebands at GHz frequencies will be imprinted on the laser beams between spacecraft. Differential phase noise between the carrier and a sideband introduced within the optical chain must be very low. We report on a transportable setup to measure the phase fidelity of optical amplifiers.

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

    PubMed

    Pentelute, Brad L; Kent, Stephen B H

    2007-02-15

    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].

  4. Measurements of the torque moment in various archwire-bracket-ligation combinations.

    PubMed

    Hirai, Miyuki; Nakajima, Akira; Kawai, Nobuhiko; Tanaka, Eiji; Igarashi, Yu; Sakaguchi, Masahito; Sameshima, Glenn T; Shimizu, Noriyoshi

    2012-06-01

    The torque moment generated by third-order bends is important for tooth movement. The purpose of this study was to measure the torque moment that can be delivered by various archwire and bracket combinations at the targeted tooth. Stainless steel (SS) upper brackets with 0.018 and 0.022 inch slots, two sizes of nickel-titanium (Ni-Ti) alloy wires, and three sizes of SS wires for each bracket were used. The wire was ligated with elastics or wire. The torque moment delivered by the various archwire-bracket-ligation combinations was measured using a torque gauge. Statistical analysis was undertaken using analysis of variance (multiple comparison tests and post hoc using Tukey's honestly significant difference test. The torque moment increased as the degree of torque and wire size increased. There was no significant difference in torque moment between the SS and Ni-Ti wires at lower or higher than 40 degrees torque. The torque moment with wire ligation was significantly larger than that with elastic ligation with 0.016 × 0.022 and 0.017 × 0.025 inch Ni-Ti wires in the 0.018 inch slot brackets and the 0.017 × 0.025 and 0.019 × 0.025 inch SS and Ni-Ti wires in the 0.022 inch slot brackets. However, there was no significant difference in torque moment between either ligation method when using the full slot size wires.

  5. Feeding practices and patent ductus arteriosus ligation preferences-are they related?

    PubMed

    Jhaveri, Nami; Soll, Roger F; Clyman, Ronald I

    2010-09-01

    We hypothesized that there is a significant relationship between a neonatologist's belief that feedings must be stopped in the presence of a patent ductus arteriosus (PDA) and his or her willingness to ligate a PDA. We administered the same survey questionnaire to two separate populations of neonatologists to assess their beliefs regarding PDA treatment practices. Although >90% of U.S. and non-U.S. neonatologists reported that they would ligate a PDA when infants with birth weights <900 g required mechanical ventilation (and indomethacin was contraindicated or had failed to close the PDA), U.S. neonatologists reported that they were significantly more likely to ligate a PDA when less respiratory support was required. U.S. neonatologists were also more likely to stop feedings when a PDA was present. The reported likelihood that a neonatologist would ligate a PDA in infants who did not require mechanical ventilation was significantly increased if the neonatologist believed that feedings had to be stopped because of the PDA. After controlling for the belief that "feedings must be stopped in the presence of a PDA," the significant difference between U.S. and non-U.S. neonatologists, in their reported desire to ligate infants who did not require mechanical ventilation, was no longer present.

  6. A Relaxed Active Site After Exon Ligation by the Group I Intron

    SciTech Connect

    Lipchock,S.; Strobel, S.

    2008-01-01

    During RNA maturation, the group I intron promotes two sequential phosphorotransfer reactions resulting in exon ligation and intron release. Here, we report the crystal structure of the intron in complex with spliced exons and two additional structures that examine the role of active-site metal ions during the second step of RNA splicing. These structures reveal a relaxed active site, in which direct metal coordination by the exons is lost after ligation, while other tertiary interactions are retained between the exon and the intron. Consistent with these structural observations, kinetic and thermodynamic measurements show that the scissile phosphate makes direct contact with metals in the ground state before exon ligation and in the transition state, but not after exon ligation. Despite no direct exonic interactions and even in the absence of the scissile phosphate, two metal ions remain bound within the active site. Together, these data suggest that release of the ligated exons from the intron is preceded by a change in substrate-metal coordination before tertiary hydrogen bonding contacts to the exons are broken.

  7. The role of reactivity in DNA templated native chemical PNA ligation during PCR.

    PubMed

    Roloff, Alexander; Seitz, Oliver

    2013-06-15

    DNA templated fluorogenic reactions have been used as a diagnostic tool for the sequence specific detection of nucleic acids; and it has been shown that the native chemical ligation between thioester- and 1,2-aminothiol-modified PNA probes is amongst the most selective DNA detection methods reported. We explored whether a DNA templated reaction can be interfaced with the polymerase chain reaction (PCR). This endeavor posed a significant challenge. The reactive groups involved must be sufficiently stable to tolerate the high temperature applied in the PCR process. Nevertheless, the ligation reaction must proceed very rapidly and sequence specifically within the short time available in the annealing and primer extension steps before denaturation is used after approx. 1 min to commence the next PCR cycle. This required a careful optimization of the ternary complex architecture as well as adjustments of probe length and probe reactivities. Our results point to the prime importance of the ligation architecture. We show that once suitable annealing sites have been identified less reactive probe sets may be preferable if sequence specificity is of major concern. The reactivity tuning enabled the development of an in-PCR ligation, which was used for the single nucleotide specific typing of the V600E (T1799A) point mutation in the human BRaf gene. Showcasing the efficiency and sequence specificity of native chemical PNA ligation, attomolar template proofed sufficient to trigger signal while a 1000-fold higher load of single mismatched template failed to induce appreciable signal.

  8. Neonatal Patent Ductus Arteriosus Ligation Operations Performed by Adult Cardiac Surgeons.

    PubMed

    Chung, Yoon Sang; Cho, Dai Yun; Kang, Hyun; Lee, Na Mi; Hong, Joonhwa

    2017-08-01

    Patent ductus arteriosus (PDA) ligation is usually performed by congenital cardiac surgeons. However, due to the uneven distribution of congenital cardiac surgeons in South Korea, many institutions depend solely on adult cardiac surgeons for congenital cardiac diseases. We report the outcomes of PDA ligations performed by adult cardiac surgeons at our institution. The electronic medical records of 852 neonates at Chung-Ang University Hospital, Seoul, South Korea from November 2010 to May 2014 were reviewed to identify patients with PDA. Of the 111 neonates with a diagnosis of PDA, 26 (23%) underwent PDA ligation. PDAs were ligated within 28 days of birth (mean, 14.5±7.8 days), and the mean gestational age of these patients was 30.3±4.6 weeks (range, 26 to 40 weeks) with a mean birth weight of 1,292.5±703.5 g (range, 480 to 3,020 g). No residual shunts through the PDA were found on postoperative echocardiography. There was 1 case of 30-day mortality (3.8%) due to pneumonia, and 6 cases of in-hospital mortality (23.1%) after 30 days, which is comparable to results from other centers with congenital cardiac surgery programs. Although our outcomes may not be generalizable to all hospital settings without a congenital cardiac surgery program, in select centers, PDA ligations can be performed safely by adult cardiac surgeons if no congenital cardiac surgery program is available.

  9. Air-powder polishing on self-ligating brackets after clinical use: effects on debris levels

    PubMed Central

    Aragón, Mônica L. S. Castro; Lima, Leandro Santiago; Normando, David

    2016-01-01

    ABSTRACT Introduction: Debris buildup on brackets and arch surfaces is one of the main factors that can influence the intensity of friction between bracket and orthodontic wire. Objective: This study sought to evaluate the effect of air-powder polishing cleaning on debris levels of self-ligating ceramic brackets at the end of orthodontic treatment, compared to the behavior of conventional brackets. Methods: Debris levels were evaluated in metal conventional orthodontic brackets (n = 42) and ceramic self-ligating brackets (n = 42) on canines and premolars, arranged in pairs. There were brackets with and without air-powder polishing. At the end of orthodontic treatment, a hemiarch served as control and the contralateral hemiarch underwent prophylaxis with air-powder polishing. Debris buildup in bracket slots was assessed through images, and Wilcoxon test was used to analyze the results. Results: The median debris levels were statistically lower in the conventional metal brackets compared to self-ligating ones (p = 0.02), regarding brackets not submitted to air-powder polishing. Polishing significantly reduced debris buildup to zero in both systems, without differences between groups. Conclusions: Ceramic self-ligating brackets have a higher debris buildup in comparison to conventional metal brackets in vivo, but prophylaxis with sodium bicarbonate jet was effective in reducing debris levels in self-ligating and also in conventional brackets. PMID:27901234

  10. No Scalpel Vasectomy (NSV) with Ligation and Excision: A Single Centre Experience.

    PubMed

    Bhuyan, K; Ali, I; Sarma, G; Das, U

    2015-12-01

    No scalpel vasectomy (NSV) has proved to be a safe and simple procedure for permanent sterilization for men. Ligation and excision of the vas deferens followed by fascial interposition is the procedure of choice. It is believed that vas excision without fascial interposition has a risk of failure. The objective of this study was to evaluate the technique of NSV with ligation and excision only. No scalpel vasectomy performed in an urban centre was taken for this prospective study. Only ligation and excision procedure was applied in its execution. It was demonstrated and performed under the supervision of an expert. Information regarding early and late complications including failure was gathered. A total number of 3,392 NSVs were performed in an urban training centre between Apr' 2009 to Mar' 2013. The procedure applied was only excision and ligation of the vas deferens. The fascial interposition was not included in the procedure. Haematoma (1), bleeding (3), foreign body granuloma (1), scrotal pain (3), epididymitis (1) and sinus formations (1) were encountered. There was only one failure in the whole group of acceptors. NSV with ligation and excision is a simple and easy procedure to learn and perform. Complications and failures are negligible. The additional fascial interposition needs more surgical skill and is time-consuming, hence can be avoided where a large number of acceptors need to undergo NSV in a rural camp.

  11. An oxazetidine amino acid for chemical protein synthesis by rapid, serine-forming ligations

    NASA Astrophysics Data System (ADS)

    Pusterla, Ivano; Bode, Jeffrey W.

    2015-08-01

    Amide-forming ligation reactions allow the chemical synthesis of proteins by the union of unprotected peptide segments, and enable the preparation of protein derivatives not accessible by expression or bioengineering approaches. The native chemical ligation (NCL) of thioesters and N-terminal cysteines is unquestionably the most successful approach, but is not ideal for all synthetic targets. Here we describe the synthesis of an Fmoc-protected oxazetidine amino acid for use in the α-ketoacid-hydroxylamine (KAHA) amide ligation. When incorporated at the N-terminus of a peptide segment, this four-membered cyclic hydroxylamine can be used for rapid serine-forming ligations with peptide α-ketoacids. This ligation operates at low concentration (100 μM-5 mM) and mild temperatures (20-25 °C). The utility of the reaction was demonstrated by the synthesis of S100A4, a 12 kDa calcium-binding protein not easily accessible by NCL or other amide-forming reactions due to its primary sequence and properties.

  12. Unfavorable lipid profile and higher frequency of hot flashes during perimenopausal years after fallopian tube ligation.

    PubMed

    Özkaya, Enis; Gokmen, Oya; Tosun, Alptekin; Kucuk, Emine; Baris, Songül; Korkmaz, Vakkas; Usta, Murat

    2013-06-01

    We sought to study the effect of tubal ligation on lipid profile, ovarian reserve and hot flashes during perimenopausal years. A total of 210 perimenopausal women complaining of abnormal vaginal bleeding were enrolled for the study. Subjects' menstrual, reproductive and medical histories were recorded. Serum FSH, LH and estradiol levels were screened in all women to determine menopausal status. In order to rule out any gynecologic pathology, all subjects underwent transvaginal sonography. Women were divided into two groups according to presence (study group, n = 68) or absence (control group, n = 142) of tubal ligation history. Lipid profiles and ovarian reserve tests were compared between groups. Mean age, parity, serum hemoglobin (Hb), high density lipoprotein (HDL-C), triglyceride, estradiol levels, endometrial thickness and frequency of hot flashes were significantly different between groups (p < 0.05). Mean age was 42.8 ± 1.9 years in women with tubal ligation and 45.9 ± 3.5 years in control group. Mean serum estradiol level was lower in group with tubal ligation (41.4 versus 92.5 pg/ml). Mean endometrial thickness was higher in control group (10.2 versus 7.5 mm). Age-adjusted serum Hb, HDL-C, triglyceride, estradiol, FSH level, endometrial thickness and frequency of hot flashes remained significantly different between groups (p < 0.05). Tubal ligation is associated with unfavorable lipid profile and higher frequency of hot flashes during perimenopausal years.

  13. Nucleosome linker proteins HMGB1 and histone H1 differentially enhance DNA ligation reactions.

    PubMed

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

    2002-03-22

    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.

  14. In vitro oxidative stress induced by conventional and self-ligating brackets.

    PubMed

    Buljan, Zorana Ivankovic; Ribaric, Sonja Pezelj; Abram, Maja; Ivankovic, Ante; Spalj, Stjepan

    2012-03-01

    To determine the in vitro oxidative stress induced by conventional and self-ligating brackets made of different materials. The concentration of oxidative stress marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA of murine fibroblast cells L929 after in vitro exposure to three types of conventional and four types of self-ligating brackets was assessed. To determine viability and changes in the number of cells before and after exposure, trypan blue dye was used. Analysis of variance (ANOVA) was used for statistical analysis. No significant difference in cell viability was noted between metal, ceramic, and polymeric conventional brackets, and self-ligating brackets made of combinations of those materials, but viability was significantly higher compared with positive controls (P < .05). The conventional sapphire ceramic bracket (Inspire Ice) showed high viability, the largest increase in the number of cells, and the lowest oxidative stress. A higher concentration of markers of oxidative stress was observed in full metal conventional and self-ligating brackets (MiniSprint and Speed) and in conventional polyurethane brackets (Quantum) compared with negative controls (P < .05). All types of orthodontic brackets, regardless of the constituent materials, are a source of oxidative stress in vitro, but the highest stress was induced in the full metal and polyurethane brackets. Conventional ceramic brackets show the highest degree of biocompatibility compared with polymeric and metal brackets and self-ligating brackets made from combinations of these materials.

  15. A comparison of the Ameroid constrictor versus ligation in the surgical management of single extrahepatic portosystemic shunts.

    PubMed

    Murphy, S T; Ellison, G W; Long, M; Van Gilder, J

    2001-01-01

    Twenty-two dogs were managed surgically for a single extrahepatic portosystemic shunt; 12 with surgical ligation and 10 with an Ameroid constrictor. Utilization of the Ameroid constrictor significantly decreased surgery time to approximately half that of the ligation technique. A decreased intraoperative and postoperative complication rate was noted with the Ameroid constrictor group. Follow-up evaluation demonstrated comparable efficacy when comparing surgical techniques. The Ameroid constrictor offered a surgical occlusion technique for management of a single extra-hepatic portosystemic shunt that was equally effective to ligation while shortening surgical time and minimizing the risks that are commonly associated with ligation of the shunting vessel.

  16. Subtotal nephrectomy plus coronary ligation leads to more pronounced damage in both organs than either nephrectomy or coronary ligation.

    PubMed

    Bongartz, Lennart G; Joles, Jaap A; Verhaar, Marianne C; Cramer, Maarten J; Goldschmeding, Roel; Tilburgs, Chantal; Gaillard, Carlo A; Doevendans, Pieter A; Braam, Branko

    2012-02-01

    Coexistence of chronic kidney disease (CKD) and heart failure (HF) in humans is associated with poor outcome. We hypothesized that preexistent CKD worsens cardiac outcome after myocardial infarction, and conversely that ensuing HF worsens progression of CKD. Subtotally nephrectomized (SNX) or sham-operated (CON) rats were subjected to coronary ligation (CL) or sham surgery in week 9 to realize four groups: CON, SNX, CON + CL, and SNX + CL. Blood pressure and renal function were measured in weeks 8, 11, 13, and 15. In week 16, cardiac hemodynamics and end-organ damage were assessed. Blood pressure was significantly lower in SNX + CL vs. SNX. Despite this, glomerulosclerosis was more severe in SNX + CL vs. SNX. Two weeks after CL, SNX + CL had more cardiac dilatation compared with CON + CL (end-diastolic volume index: 0.28 ± 0.04 vs. 0.19 ± 0.03 ml/100 g body wt; mean ± SD, P < 0.001), although infarct size was similar. During follow-up in SNX + CL, ejection fraction declined. Mortality was only observed in SNX + CL (2 out of 9). In SNX + CL, end-diastolic pressure (18 ± 4 mmHg) and tau (29 ± 9 ms), the time constant of active relaxation, were significantly higher compared with SNX (13 ± 3 mmHg, 20 ± 4 ms; P < 0.01) and CON + CL (11 ± 5 mmHg, 17 ± 2 ms; P < 0.01). The diameter of small arterioles in the myocardium was significantly decreased in SNX + CL vs. CON + CL (P < 0.01). Urinary excretion of NO metabolites was significantly lower in SNX + CL compared with both CL and SNX. This study demonstrates the existence of more heart and more kidney damage in a new model of combined CKD and HF than in the individual models. Such enhanced damage appears to be separate from systemic hemodynamic changes. Reduced nitric oxide availability may have played a role in both worsened glomerulosclerosis and cardiac diastolic function and appears to be a connector in the cardiorenal syndrome.

  17. AMPLIFIED TELEPHONE AS A TEACHING MEDIUM.

    ERIC Educational Resources Information Center

    JOLLY, JOAN; MADDEN, CHARLES F.

    A GRANT TOTALING $58,400 FROM THE FUND FOR THE ADVANCEMENT OF EDUCATION ENABLED STEPHENS COLLEGE TO INITIATE AN EXPERIMENTAL EDUCATIONAL PROGRAM BY WHICH AMPLIFIED TELEPHONE COMMUNICATION BROUGHT HIGH-QUALITY INSTRUCTION TO GROUPS OF SMALL LIBERAL ARTS COLLEGES. A "MASTER TEACHER" ORGANIZED AND PRESENTED THE BASIC MATERIALS OF THE…

  18. LOW-LEVEL DIRECT CURRENT AMPLIFIER

    DOEpatents

    Kerns, Q.A.

    1959-05-01

    A d-c amplifier is described. Modulation is provided between a d-c signal and an alternating current to give an output signal proportional to the d- c signal. The circuit has high sensitivity and accuracy. (T.R.H.)

  19. Stereoscopy Amplifies Emotions Elicited by Facial Expressions

    PubMed Central

    Kätsyri, Jari; Häkkinen, Jukka

    2015-01-01

    Mediated facial expressions do not elicit emotions as strongly as real-life facial expressions, possibly due to the low fidelity of pictorial presentations in typical mediation technologies. In the present study, we investigated the extent to which stereoscopy amplifies emotions elicited by images of neutral, angry, and happy facial expressions. The emotional self-reports of positive and negative valence (which were evaluated separately) and arousal of 40 participants were recorded. The magnitude of perceived depth in the stereoscopic images was manipulated by varying the camera base at 15, 40, 65, 90, and 115 mm. The analyses controlled for participants’ gender, gender match, emotional empathy, and trait alexithymia. The results indicated that stereoscopy significantly amplified the negative valence and arousal elicited by angry expressions at the most natural (65 mm) camera base, whereas stereoscopy amplified the positive valence elicited by happy expressions in both the narrowed and most natural (15–65 mm) base conditions. Overall, the results indicate that stereoscopy amplifies the emotions elicited by mediated emotional facial expressions when the depth geometry is close to natural. The findings highlight the sensitivity of the visual system to depth and its effect on emotions. PMID:27551358

  20. Amplified Optomechanical Transduction of Virtual Radiation Pressure

    NASA Astrophysics Data System (ADS)

    Cirio, Mauro; Debnath, Kamanasish; Lambert, Neill; Nori, Franco

    2017-08-01

    Here we describe how, utilizing a time-dependent optomechanical interaction, a mechanical probe can provide an amplified measurement of the virtual photons dressing the quantum ground state of an ultrastrongly coupled light-matter system. We calculate the thermal noise tolerated by this measurement scheme and discuss an experimental setup in which it could be realized.