Sample records for acid amplification technology

  1. Miniaturized isothermal nucleic acid amplification, a review. (United States)

    Asiello, Peter J; Baeumner, Antje J


    Micro-Total Analysis Systems (µTAS) for use in on-site rapid detection of DNA or RNA are increasingly being developed. Here, amplification of the target sequence is key to increasing sensitivity, enabling single-cell and few-copy nucleic acid detection. The several advantages to miniaturizing amplification reactions and coupling them with sample preparation and detection on the same chip are well known and include fewer manual steps, preventing contamination, and significantly reducing the volume of expensive reagents. To-date, the majority of miniaturized systems for nucleic acid analysis have used the polymerase chain reaction (PCR) for amplification and those systems are covered in previous reviews. This review provides a thorough overview of miniaturized analysis systems using alternatives to PCR, specifically isothermal amplification reactions. With no need for thermal cycling, isothermal microsystems can be designed to be simple and low-energy consuming and therefore may outperform PCR in portable, battery-operated detection systems in the future. The main isothermal methods as miniaturized systems reviewed here include nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP), helicase-dependent amplification (HDA), rolling circle amplification (RCA), and strand displacement amplification (SDA). Also, important design criteria for the miniaturized devices are discussed. Finally, the potential of miniaturization of some new isothermal methods such as the exponential amplification reaction (EXPAR), isothermal and chimeric primer-initiated amplification of nucleic acids (ICANs), signal-mediated amplification of RNA technology (SMART) and others is presented.

  2. Isothermal Amplification of Nucleic Acids. (United States)

    Zhao, Yongxi; Chen, Feng; Li, Qian; Wang, Lihua; Fan, Chunhai


    Isothermal amplification of nucleic acids is a simple process that rapidly and efficiently accumulates nucleic acid sequences at constant temperature. Since the early 1990s, various isothermal amplification techniques have been developed as alternatives to polymerase chain reaction (PCR). These isothermal amplification methods have been used for biosensing targets such as DNA, RNA, cells, proteins, small molecules, and ions. The applications of these techniques for in situ or intracellular bioimaging and sequencing have been amply demonstrated. Amplicons produced by isothermal amplification methods have also been utilized to construct versatile nucleic acid nanomaterials for promising applications in biomedicine, bioimaging, and biosensing. The integration of isothermal amplification into microsystems or portable devices improves nucleic acid-based on-site assays and confers high sensitivity. Single-cell and single-molecule analyses have also been implemented based on integrated microfluidic systems. In this review, we provide a comprehensive overview of the isothermal amplification of nucleic acids encompassing work published in the past two decades. First, different isothermal amplification techniques are classified into three types based on reaction kinetics. Then, we summarize the applications of isothermal amplification in bioanalysis, diagnostics, nanotechnology, materials science, and device integration. Finally, several challenges and perspectives in the field are discussed.

  3. Development of Lentivirus-Based Reference Materials for Ebola Virus Nucleic Acid Amplification Technology-Based Assays. (United States)

    Mattiuzzo, Giada; Ashall, James; Doris, Kathryn S; MacLellan-Gibson, Kirsty; Nicolson, Carolyn; Wilkinson, Dianna E; Harvey, Ruth; Almond, Neil; Anderson, Robert; Efstathiou, Stacey; Minor, Philip D; Page, Mark


    The 2013-present Ebola virus outbreak in Western Africa has prompted the production of many diagnostic assays, mostly based on nucleic acid amplification technologies (NAT). The calibration and performance assessment of established assays and those under evaluation requires reference materials that can be used in parallel with the clinical sample to standardise or control for every step of the procedure, from extraction to the final qualitative/quantitative result. We have developed safe and stable Ebola virus RNA reference materials by encapsidating anti sense viral RNA into HIV-1-like particles. The lentiviral particles are replication-deficient and non-infectious due to the lack of HIV-1 genes and Envelope protein. Ebola virus genes were subcloned for encapsidation into two lentiviral preparations, one containing NP-VP35-GP and the other VP40 and L RNA. Each reference material was formulated as a high-titre standard for use as a calibrator for secondary or internal standards, and a 10,000-fold lower titre preparation to serve as an in-run control. The preparations have been freeze-dried to maximise stability. These HIV-Ebola virus RNA reference materials were suitable for use with in-house and commercial quantitative RT-PCR assays and with digital RT-PCR. The HIV-Ebola virus RNA reference materials are stable at up to 37°C for two weeks, allowing the shipment of the material worldwide at ambient temperature. These results support further evaluation of the HIV-Ebola virus RNA reference materials as part of an International collaborative study for the establishment of the 1st International Standard for Ebola virus RNA.

  4. Higher specificity of nucleic acid sequence-based amplification isothermal technology than of real-time PCR for quantification of HIV-1 RNA on dried blood spots. (United States)

    Mercier-Delarue, Severine; Vray, Muriel; Plantier, Jean Christophe; Maillard, Theodora; Adjout, Zidan; de Olivera, Fabienne; Schnepf, Nathalie; Maylin, Sarah; Simon, Francois; Delaugerre, Constance


    Dried blood spots (DBS) are widely proposed as a plasma surrogate for monitoring antiretroviral treatment efficacy based on the HIV-1 RNA level (viral load [VL]) in resource-limited settings. Interfering coamplification of cell-associated HIV-1 DNA during reverse transcription (RT)-PCR can be avoided by using nucleic acid sequence-based amplification (NASBA) technology, which is based on an RNA template and isothermic conditions. We analyzed VL values obtained with DBS and plasma samples by comparing isothermic NASBA (NucliSENS EasyQ HIV-1 V2.0; bioMérieux) with real-time RT-PCR (Cobas TaqMan HIV-1 V2.0; Roche). Samples from 197 HIV-1-infected patients were tested (non-B subtypes in 51% of the cases). Nucleic acid extractions were performed by use of NucliSENS EasyMAG (bioMérieux) and Cobas AmpliPrep (Roche) before the NASBA and RT-PCR quantifications, respectively. Both quantification assays have lower limits of detection of 20 (1.3) and 800 (2.9) log10 copies/ml (log) in plasma and DBS, respectively. The mean (DBS minus plasma) differences were -0.39 and -0.46 log, respectively, for RT-PCR and NASBA. RT-PCR on DBS identified virological failure in 122 of 126 patients (sensitivity, 97%) and viral suppression in 58 of 70 patients (specificity, 83%), yielding 12 false-positive results (median, 3.2 log). NASBA on DBS identified virological failure in 85 of 96 patients (sensitivity, 89%) and viral suppression in 95 of 97 patients (specificity, 98%) and yielded 2 false-positive results (3.0 log for both). Both technologies detected HIV-1 RNA in DBS at a threshold of 800 copies/ml. This higher specificity of NASBA technology could avoid overestimation of poor compliance or the emergence of resistance when monitoring antiretroviral efficacy with the DBS method.

  5. Bioanalytical applications of isothermal nucleic acid amplification techniques. (United States)

    Deng, Huimin; Gao, Zhiqiang


    The most popular in vitro nucleic acid amplification techniques like polymerase chain reaction (PCR) including real-time PCR are costly and require thermocycling, rendering them unsuitable for uses at point-of-care. Highly efficient in vitro nucleic acid amplification techniques using simple, portable and low-cost instruments are crucial in disease diagnosis, mutation detection and biodefense. Toward this goal, isothermal amplification techniques that represent a group of attractive in vitro nucleic acid amplification techniques for bioanalysis have been developed. Unlike PCR where polymerases are easily deactivated by thermally labile constituents in a sample, some of the isothermal nucleic acid amplification techniques, such as helicase-dependent amplification and nucleic acid sequence-based amplification, enable the detection of bioanalytes with much simplified protocols and with minimal sample preparations since the entire amplification processes are performed isothermally. This review focuses on the isothermal nucleic acid amplification techniques and their applications in bioanalytical chemistry. Starting off from their amplification mechanisms and significant properties, the adoption of isothermal amplification techniques in bioanalytical chemistry and their future perspectives are discussed. Representative examples illustrating the performance and advantages of each isothermal amplification technique are discussed along with some discussion on the advantages and disadvantages of each technique.

  6. One New Method of Nucleic Acid Amplification-Loop-mediated Isothermal Amplification of DNA

    Institute of Scientific and Technical Information of China (English)

    Xue-en FANG; Jian LI; Qin CHEN


    Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method, which amplifies DNA with high specificity, sensitivity, rapidity and efficiency under isothermal conditions using a set of four specially designed primers and a Bst DNA polymerase with strand displacement activity. The basic principle, characteristics, development of LAMP and its applications are summarized in this article.

  7. Isothermal amplification detection of nucleic acids by a double-nicked beacon. (United States)

    Shi, Chao; Zhou, Meiling; Pan, Mei; Zhong, Guilin; Ma, Cuiping


    Isothermal and rapid amplification detection of nucleic acids is an important technology in environmental monitoring, foodborne pathogen detection, and point-of-care clinical diagnostics. Here we have developed a novel method of isothermal signal amplification for single-stranded DNA (ssDNA) detection. The ssDNA target could be used as an initiator, coupled with a double-nicked molecular beacon, to originate amplification cycles, achieving cascade signal amplification. In addition, the method showed good specificity and strong anti-jamming capability. Overall, it is a one-pot and isothermal strand displacement amplification method without the requirement of a stepwise procedure, which greatly simplifies the experimental procedure and decreases the probability of contamination of samples. With its advantages, the method would be very useful to detect nucleic acids in point-of-care or field use.

  8. Loop-mediated isothermal amplification for detection of nucleic acids. (United States)

    Tanner, Nathan A; Evans, Thomas C


    Sequence-specific isothermal nucleic acid amplification techniques are ideally suited for use in molecular diagnostic applications because they do not require thermal cycling equipment and the reactions are typically fast. One of the most widely cited isothermal techniques is termed loop-mediated isothermal amplification (LAMP). This protocol allows amplification times as fast as 5 to 10 min. Furthermore, various methodologies to detect amplification have been applied to LAMP to increase its utility for the point-of-care market. Basic LAMP protocols are provided herein for detection of specific DNA and RNA targets, along with a method to perform multiplex LAMP reactions, permitting even greater flexibility from this powerful technique.

  9. Nucleic acid amplification: Alternative methods of polymerase chain reaction. (United States)

    Fakruddin, Md; Mannan, Khanjada Shahnewaj Bin; Chowdhury, Abhijit; Mazumdar, Reaz Mohammad; Hossain, Md Nur; Islam, Sumaiya; Chowdhury, Md Alimuddin


    Nucleic acid amplification is a valuable molecular tool not only in basic research but also in application oriented fields, such as clinical medicine development, infectious diseases diagnosis, gene cloning and industrial quality control. A comperehensive review of the literature on the principles, applications, challenges and prospects of different alternative methods of polymerase chain reaction (PCR) was performed. PCR was the first nucleic acid amplification method. With the advancement of research, a no of alternative nucleic acid amplification methods has been developed such as loop mediated isothermal amplification, nucleic acid sequence based amplification, strand displacement amplification, multiple displacement amplification. Most of the alternative methods are isothermal obviating the need for thermal cyclers. Though principles of most of the alternate methods are relatively complex than that of PCR, they offer better applicability and sensitivity in cases where PCR has limitations. Most of the alternate methods still have to prove themselves through extensive validation studies and are not available in commercial form; they pose the potentiality to be used as replacements of PCR. Continuous research is going on in different parts of the world to make these methods viable technically and economically.

  10. Strand Invasion Based Amplification (SIBA®: a novel isothermal DNA amplification technology demonstrating high specificity and sensitivity for a single molecule of target analyte.

    Directory of Open Access Journals (Sweden)

    Mark J Hoser

    Full Text Available Isothermal nucleic acid amplification technologies offer significant advantages over polymerase chain reaction (PCR in that they do not require thermal cycling or sophisticated laboratory equipment. However, non-target-dependent amplification has limited the sensitivity of isothermal technologies and complex probes are usually required to distinguish between non-specific and target-dependent amplification. Here, we report a novel isothermal nucleic acid amplification technology, Strand Invasion Based Amplification (SIBA. SIBA technology is resistant to non-specific amplification, is able to detect a single molecule of target analyte, and does not require target-specific probes. The technology relies on the recombinase-dependent insertion of an invasion oligonucleotide (IO into the double-stranded target nucleic acid. The duplex regions peripheral to the IO insertion site dissociate, thereby enabling target-specific primers to bind. A polymerase then extends the primers onto the target nucleic acid leading to exponential amplification of the target. The primers are not substrates for the recombinase and are, therefore unable to extend the target template in the absence of the IO. The inclusion of 2'-O-methyl RNA to the IO ensures that it is not extendible and that it does not take part in the extension of the target template. These characteristics ensure that the technology is resistant to non-specific amplification since primer dimers or mis-priming are unable to exponentially amplify. Consequently, SIBA is highly specific and able to distinguish closely-related species with single molecule sensitivity in the absence of complex probes or sophisticated laboratory equipment. Here, we describe this technology in detail and demonstrate its use for the detection of Salmonella.

  11. Isothermal nucleic acid amplification technology applied in detection of Salmonella%恒温扩增核酸法检测沙门菌属效果分析

    Institute of Scientific and Technical Information of China (English)

    肖征; 刘秀贞


    目的 观察核酸恒温扩增商品试剂盒对沙门菌属的检测效果.方法 对商品销售的两种恒温扩增检测试剂与普通PCR试剂盒进行检测灵敏度、特异性及操作简便性的比较.结果 常规PCR法A、恒温扩增试剂B及C检测沙门菌属的灵敏度分别为约4×103 CFU/ml、4×103 CFU/ml和约4×104 CFU/ml;对21株临床分离的沙门菌属的检测阳性率分别为76.2%、28.6%和100.0%;用11株非沙门肠道菌株直接检测的特异性均为100.0%;检测过程除常规的核酸提取外,核酸扩增常规法、试剂B、C的核酸检测和结果观察的时间约为2、2、2.5h,以常规法及试剂C的结果观察方式比较方便.结论 试剂C操作时间短、使用方便、检测敏感度及特异性比较好,是一种适用于对沙门菌属快速检测的恒温扩增试剂;对待商品试剂应做好试用工作,以选择好真正适用的产品.%OBJECTIVE To evaluate the efficacy of commercially available isothermal nucleic amplification technology reagents in detecting Salmonella spp. METHODS The routine PCR reagent (A) was compared with two commercially available isothermal nucleic amplification reagents (B and C) for their sensitivity, specificity and operation flexibility in detecting Salmonella spp. RESULTS Reagent A, B and C showed sensitivity of detecting 4 X103 CFU/ml, 4 X 103 CFU/ml and 4 X 104 CFU/ml of Salmonella spp, respectively. The positive rates of detection of clinically isolated Salmonella spp were 76. 2%, 28. 6% and 100. 0%, respectively; all reagents showed no reactions with 11 non-Salmonella enteric bacteria strains with the specificity of 100. 0%; the methods A,B and C took 2, 2 and 2. 5 hours respectively to complete the amplification and results reading after the common procedure of DNA extraction. It was more convenient to observe the results with reagents A and C than B. CONCLUSION Reagent C can be used in field test for Salmonella .spp detection. It is suggested that

  12. Parametric Analog Signal Amplification Applied to Nanoscale CMOS Technologies

    CERN Document Server

    Oliveira, João P


    This book is dedicated to the analysis of parametric amplification with special emphasis on the MOS discrete-time implementation. This implementation is demonstrated by the presentation of several circuits where the MOS parametric amplifier cell is used: small gain amplifier, comparator with embedded pre-amplification, discrete-time mixer/IIR-Filter, and analog-to-digital converter (ADC).  Experimental results are shown to validate the overall design technique. Provides the complete theoretical analysis, supported by electrical simulations, of the parametric amplification technique in both continuous time and discrete time domains; Describes the design flow of an ADC fully based on discrete-time parametric amplification in CMOS technology; Presents a high speed time-interleaved pipeline ADC, based on parametric MOS amplification techniques described, complementing theory discussed with experimental results.

  13. Real-time electrochemical monitoring of isothermal helicase-dependent amplification of nucleic acids. (United States)

    Kivlehan, Francine; Mavré, François; Talini, Luc; Limoges, Benoît; Marchal, Damien


    We described an electrochemical method to monitor in real-time the isothermal helicase-dependent amplification of nucleic acids. The principle of detection is simple and well-adapted to the development of portable, easy-to-use and inexpensive nucleic acids detection technologies. It consists of monitoring a decrease in the electrochemical current response of a reporter DNA intercalating redox probe during the isothermal DNA amplification. The method offers the possibility to quantitatively analyze target nucleic acids in less than one hour at a single constant temperature, and to perform at the end of the isothermal amplification a DNA melt curve analysis for differentiating between specific and non-specific amplifications. To illustrate the potentialities of this approach for the development of a simple, robust and low-cost instrument with high throughput capability, the method was validated with an electrochemical system capable of monitoring up to 48 real-time isothermal HDA reactions simultaneously in a disposable microplate consisting of 48-electrochemical microwells. Results obtained with this approach are comparable to that obtained with a well-established but more sophisticated and expensive fluorescence-based method. This makes for a promising alternative detection method not only for real-time isothermal helicase-dependent amplification of nucleic acid, but also for other isothermal DNA amplification strategies.

  14. Application of a Non-amplification based Technology to Detect Invasive Fungal Pathogens (United States)

    Hsu, Joe L.; Binkley, Jon; Clemons, Karl V.; Stevens, David A.; Nicolls, Mark R.; Holodniy, Mark


    Current diagnostic techniques for fungal diseases could be improved with respect to sensitivity, specificity and timeliness. To address this clinical need, we adapted a non-amplification based nucleic acid detection technology to identify fungal pathogens. We demonstrate a high-specificity, detection sensitivity, reproducibility and multiplex capacity for detecting fungal strains. PMID:24359934

  15. Novel bioluminescent quantitative detection of nucleic acid amplification in real-time.

    Directory of Open Access Journals (Sweden)

    Olga A Gandelman

    Full Text Available BACKGROUND: The real-time monitoring of polynucleotide amplification is at the core of most molecular assays. This conventionally relies on fluorescent detection of the amplicon produced, requiring complex and costly hardware, often restricting it to specialised laboratories. PRINCIPAL FINDINGS: Here we report the first real-time, closed-tube luminescent reporter system for nucleic acid amplification technologies (NAATs enabling the progress of amplification to be continuously monitored using simple light measuring equipment. The Bioluminescent Assay in Real-Time (BART continuously reports through bioluminescent output the exponential increase of inorganic pyrophosphate (PPi produced during the isothermal amplification of a specific nucleic acid target. BART relies on the coupled conversion of inorganic pyrophosphate (PPi produced stoichiometrically during nucleic acid synthesis to ATP by the enzyme ATP sulfurylase, and can therefore be coupled to a wide range of isothermal NAATs. During nucleic acid amplification, enzymatic conversion of PPi released during DNA synthesis into ATP is continuously monitored through the bioluminescence generated by thermostable firefly luciferase. The assay shows a unique kinetic signature for nucleic acid amplifications with a readily identifiable light output peak, whose timing is proportional to the concentration of original target nucleic acid. This allows qualitative and quantitative analysis of specific targets, and readily differentiates between negative and positive samples. Since quantitation in BART is based on determination of time-to-peak rather than absolute intensity of light emission, complex or highly sensitive light detectors are not required. CONCLUSIONS: The combined chemistries of the BART reporter and amplification require only a constant temperature maintained by a heating block and are shown to be robust in the analysis of clinical samples. Since monitoring the BART reaction requires only a

  16. Integrated Microfluidic Nucleic Acid Isolation, Isothermal Amplification, and Amplicon Quantification


    Mauk, Michael G.; Changchun Liu; Jinzhao Song; Bau, Haim H.


    Microfluidic components and systems for rapid (<60 min), low-cost, convenient, field-deployable sequence-specific nucleic acid-based amplification tests (NAATs) are described. A microfluidic point-of-care (POC) diagnostics test to quantify HIV viral load from blood samples serves as a representative and instructive example to discuss the technical issues and capabilities of “lab on a chip” NAAT devices. A portable, miniaturized POC NAAT with performance comparable to conventional PCR (poly...

  17. Polyethersulfone improves isothermal nucleic acid amplification compared to current paper-based diagnostics. (United States)

    Linnes, J C; Rodriguez, N M; Liu, L; Klapperich, C M


    Devices based on rapid, paper-based, isothermal nucleic acid amplification techniques have recently emerged with the potential to fill a growing need for highly sensitive point-of-care diagnostics throughout the world. As this field develops, such devices will require optimized materials that promote amplification and sample preparation. Herein, we systematically investigated isothermal nucleic acid amplification in materials currently used in rapid diagnostics (cellulose paper, glass fiber, and nitrocellulose) and two additional porous membranes with upstream sample preparation capabilities (polyethersulfone and polycarbonate). We compared amplification efficiency from four separate DNA and RNA targets (Bordetella pertussis, Chlamydia trachomatis, Neisseria gonorrhoeae, and Influenza A H1N1) within these materials using two different isothermal amplification schemes, helicase dependent amplification (tHDA) and loop-mediated isothermal amplification (LAMP), and traditional PCR. We found that the current paper-based diagnostic membranes inhibited nucleic acid amplification when compared to membrane-free controls; however, polyethersulfone allowed for efficient amplification in both LAMP and tHDA reactions. Further, observing the performance of traditional PCR amplification within these membranes was not predicative of their effects on in situ LAMP and tHDA. Polyethersulfone is a new material for paper-based nucleic acid amplification, yet provides an optimal support for rapid molecular diagnostics for point-of-care applications.

  18. Use of signal-mediated amplification of RNA technology (SMART) to detect marine cyanophage DNA. (United States)

    Hall, M J; Wharam, S D; Weston, A; Cardy, D L N; Wilson, W H


    Here, we describe the application of an isothermal nucleic acid amplification assay, signal-mediated amplification of RNA technology (SMART), to detect DNA extracted from marine cyanophages known to infect unicellular cyanobacteria from the genus Synechococcus. The SMART assay is based on the target-dependent production of multiple copies of an RNA signal, which is measured by an enzyme-linked oligosorbent assay. SMART was able to detect both synthetic oligonucleotide targets and genomic cyanophage DNA using probes designed against the portal vertex gene (g20). Specific signals were obtained for each cyanophage strain (S-PM2 and S-BnMI). Nonspecific genomic DNA did not produce false signals or inhibit the detection of a specific target. In addition, we found that extensive purification of target DNA may not be required since signals were obtained from crude cyanophage lysates. This is the first report of the SMART assay being used to discriminate between two similar target sequences.

  19. Integrated Microfluidic Nucleic Acid Isolation, Isothermal Amplification, and Amplicon Quantification

    Directory of Open Access Journals (Sweden)

    Michael G. Mauk


    Full Text Available Microfluidic components and systems for rapid (<60 min, low-cost, convenient, field-deployable sequence-specific nucleic acid-based amplification tests (NAATs are described. A microfluidic point-of-care (POC diagnostics test to quantify HIV viral load from blood samples serves as a representative and instructive example to discuss the technical issues and capabilities of “lab on a chip” NAAT devices. A portable, miniaturized POC NAAT with performance comparable to conventional PCR (polymerase-chain reaction-based tests in clinical laboratories can be realized with a disposable, palm-sized, plastic microfluidic chip in which: (1 nucleic acids (NAs are extracted from relatively large (~mL volume sample lysates using an embedded porous silica glass fiber or cellulose binding phase (“membrane” to capture sample NAs in a flow-through, filtration mode; (2 NAs captured on the membrane are isothermally (~65 °C amplified; (3 amplicon production is monitored by real-time fluorescence detection, such as with a smartphone CCD camera serving as a low-cost detector; and (4 paraffin-encapsulated, lyophilized reagents for temperature-activated release are pre-stored in the chip. Limits of Detection (LOD better than 103 virons/sample can be achieved. A modified chip with conduits hosting a diffusion-mode amplification process provides a simple visual indicator to readily quantify sample NA template. In addition, a companion microfluidic device for extracting plasma from whole blood without a centrifuge, generating cell-free plasma for chip-based molecular diagnostics, is described. Extensions to a myriad of related applications including, for example, food testing, cancer screening, and insect genotyping are briefly surveyed.

  20. Nuclemeter: A Reaction-Diffusion Column for Quantifying Nucleic Acids Undergoing Enzymatic Amplification (United States)

    Bau, Haim; Liu, Changchun; Killawala, Chitvan; Sadik, Mohamed; Mauk, Michael


    Real-time amplification and quantification of specific nucleic acid sequences plays a major role in many medical and biotechnological applications. In the case of infectious diseases, quantification of the pathogen-load in patient specimens is critical to assessing disease progression, effectiveness of drug therapy, and emergence of drug-resistance. Typically, nucleic acid quantification requires sophisticated and expensive instruments, such as real-time PCR machines, which are not appropriate for on-site use and for low resource settings. We describe a simple, low-cost, reactiondiffusion based method for end-point quantification of target nucleic acids undergoing enzymatic amplification. The number of target molecules is inferred from the position of the reaction-diffusion front, analogous to reading temperature in a mercury thermometer. We model the process with the Fisher Kolmogoroff Petrovskii Piscounoff (FKPP) Equation and compare theoretical predictions with experimental observations. The proposed method is suitable for nucleic acid quantification at the point of care, compatible with multiplexing and high-throughput processing, and can function instrument-free. C.L. was supported by NIH/NIAID K25AI099160; M.S. was supported by the Pennsylvania Ben Franklin Technology Development Authority; C.K. and H.B. were funded, in part, by NIH/NIAID 1R41AI104418-01A1.

  1. Shortening distance of forward and reverse primers for nucleic acid isothermal amplification. (United States)

    Haitao, Qu; Wenchao, Zhang; Xiaohui, Zhang; Xiujun, Wang; Sulong, Li


    Existent nucleic acid isothermal detection techniques for clinical diseases are difficult to promote greatly due to limitations in such aspects as methodology, costs of detection, amplification efficiency and conditions for operation. There is therefore an urgent need for a new isothermal amplification method with the characteristics of high accuracy, easy operation, short time of detection and low costs. We have devised a new method of nucleic acid isothermal amplification using Bst DNA polymerase under isothermal conditions (60-65°C). We call this method of amplification by shortening the distance between forward and reverse primers for nucleic acid isothermal amplification SDAMP. The results demonstrated that this technique is highly sensitive, specific and has short reaction times (40-60 min). Results of sequencing show that the products of SDAMP amplification are mainly polymers formed by series connection of monomers formed through linkage of forward primer and complementary sequences in reverse primer via a few bases. The method is different from current methods of nucleic acid amplification. Our study shows, however, that it is a specific method of nucleic acid isothermal amplification depending on interactions between primers and DNA template.

  2. Integrated Microfluidic Nucleic Acid Isolation, Isothermal Amplification, and Amplicon Quantification. (United States)

    Mauk, Michael G; Liu, Changchun; Song, Jinzhao; Bau, Haim H


    Microfluidic components and systems for rapid (microfluidic point-of-care (POC) diagnostics test to quantify HIV viral load from blood samples serves as a representative and instructive example to discuss the technical issues and capabilities of "lab on a chip" NAAT devices. A portable, miniaturized POC NAAT with performance comparable to conventional PCR (polymerase-chain reaction)-based tests in clinical laboratories can be realized with a disposable, palm-sized, plastic microfluidic chip in which: (1) nucleic acids (NAs) are extracted from relatively large (~mL) volume sample lysates using an embedded porous silica glass fiber or cellulose binding phase ("membrane") to capture sample NAs in a flow-through, filtration mode; (2) NAs captured on the membrane are isothermally (~65 °C) amplified; (3) amplicon production is monitored by real-time fluorescence detection, such as with a smartphone CCD camera serving as a low-cost detector; and (4) paraffin-encapsulated, lyophilized reagents for temperature-activated release are pre-stored in the chip. Limits of Detection (LOD) better than 10³ virons/sample can be achieved. A modified chip with conduits hosting a diffusion-mode amplification process provides a simple visual indicator to readily quantify sample NA template. In addition, a companion microfluidic device for extracting plasma from whole blood without a centrifuge, generating cell-free plasma for chip-based molecular diagnostics, is described. Extensions to a myriad of related applications including, for example, food testing, cancer screening, and insect genotyping are briefly surveyed.

  3. Nucleic acid tool enzymes-aided signal amplification strategy for biochemical analysis: status and challenges. (United States)

    Qing, Taiping; He, Dinggeng; He, Xiaoxiao; Wang, Kemin; Xu, Fengzhou; Wen, Li; Shangguan, Jingfang; Mao, Zhengui; Lei, Yanli


    Owing to their highly efficient catalytic effects and substrate specificity, the nucleic acid tool enzymes are applied as 'nano-tools' for manipulating different nucleic acid substrates both in the test-tube and in living organisms. In addition to the function as molecular scissors and molecular glue in genetic engineering, the application of nucleic acid tool enzymes in biochemical analysis has also been extensively developed in the past few decades. Used as amplifying labels for biorecognition events, the nucleic acid tool enzymes are mainly applied in nucleic acids amplification sensing, as well as the amplification sensing of biorelated variations of nucleic acids. With the introduction of aptamers, which can bind different target molecules, the nucleic acid tool enzymes-aided signal amplification strategies can also be used to sense non-nucleic targets (e.g., ions, small molecules, proteins, and cells). This review describes and discusses the amplification strategies of nucleic acid tool enzymes-aided biosensors for biochemical analysis applications. Various analytes, including nucleic acids, ions, small molecules, proteins, and cells, are reviewed briefly. This work also addresses the future trends and outlooks for signal amplification in nucleic acid tool enzymes-aided biosensors.

  4. Powerful Amplification Cascades of FRET-Based Two-Layer Nonenzymatic Nucleic Acid Circuits. (United States)

    Quan, Ke; Huang, Jin; Yang, Xiaohai; Yang, Yanjing; Ying, Le; Wang, He; Xie, Nuli; Ou, Min; Wang, Kemin


    Nucleic acid circuits have played important roles in biological engineering and have increasingly attracted researchers' attention. They are primarily based on nucleic acid hybridizations and strand displacement reactions between nucleic acid probes of different lengths. Signal amplification schemes that do not rely on protein enzyme show great potential in analytical applications. While the single amplification circuit often achieves linear amplification that may not meet the need for detection of target in a very small amount, it is very necessary to construct cascade circuits that allow for larger amplification of inputs. Herein, we have successfully engineered powerful amplification cascades of FRET-based two-layer nonenzymatic nucleic acid circuits, in which the outputs of catalyzed hairpin assembly (CHA) activate hybridization chain reactions (HCR) circuits to induce repeated hybridization, allowing real-time monitoring of self-assembly process by FRET signal. The cascades can yield 50000-fold signal amplification with the help of the well-designed and high-quality nucleic acid circuit amplifiers. Subsequently, with coupling of structure-switching aptamer, as low as 200 pM adenosine is detected in buffer, as well as in human serum. To our knowledge, we have for the first time realized real-time monitoring adaptation of HCR to CHA circuits and achieved amplified detection of nucleic acids and small molecules with relatively high sensitivity.


    Sperm RNA Amplification for Gene Expression Profiling by DNA Microarray TechnologyHongzu Ren, Kary E. Thompson, Judith E. Schmid and David J. Dix, Reproductive Toxicology Division, NHEERL, Office of Research and Development, US Environmental Protection Agency, Research Triang...

  6. Comparison of nucleic acid sequence-based amplification and loop-mediated isothermal amplification for diagnosis of human African trypanosomiasis. (United States)

    Mugasa, Claire M; Katiti, Diana; Boobo, Alex; Lubega, George W; Schallig, Henk D F H; Matovu, Enock


    Diagnosis of human African trypanosomiasis (HAT) using molecular tests should ideally achieve high sensitivity without compromising specificity. This study compared 2 simplified tests, nucleic acid sequence-based amplification (NASBA) combined with oligochromatography (OC) and loop-mediated isothermal amplification (LAMP), executed on 181 blood samples from 65 Trypanosoma brucei gambiense HAT patients, 86 controls, and 30 serological suspects from Uganda. Basing on the composite reference standard, the diagnostic sensitivity and specificity of NASBA were 93.9% (95% confidence interval [CI] = 84.9-98.3%) and 100% (95% CI = 94.9-100%), respectively. The same parameters for LAMP were 76.9% (95% CI = 64.8-86.5%) and 100% (95% CI = 91.6-100%), respectively. The level of agreement between LAMP and microscopy was good with a kappa (κ) value of 79.2% (95% CI = 69.4-88.9%), while that of NASBA-OC/microscopy was very good (κ value 94.6%; 95% CI = 89.3-99.8%). The sensitivity of NASBA-OC was significantly higher than that of LAMP (Z = 2.723; P = 0.007). These tests have potential application to HAT surveillance.

  7. Influence of sequence mismatches on the specificity of recombinase polymerase amplification technology. (United States)

    Daher, Rana K; Stewart, Gale; Boissinot, Maurice; Boudreau, Dominique K; Bergeron, Michel G


    Recombinase polymerase amplification (RPA) technology relies on three major proteins, recombinase proteins, single-strand binding proteins, and polymerases, to specifically amplify nucleic acid sequences in an isothermal format. The performance of RPA with respect to sequence mismatches of closely-related non-target molecules is not well documented and the influence of the number and distribution of mismatches in DNA sequences on RPA amplification reaction is not well understood. We investigated the specificity of RPA by testing closely-related species bearing naturally occurring mismatches for the tuf gene sequence of Pseudomonas aeruginosa and/or Mycobacterium tuberculosis and for the cfb gene sequence of Streptococcus agalactiae. In addition, the impact of the number and distribution of mismatches on RPA efficiency was assessed by synthetically generating 14 types of mismatched forward primers for detecting five bacterial species of high diagnostic relevance such as Clostridium difficile, Staphylococcus aureus, S. agalactiae, P. aeruginosa, and M. tuberculosis as well as Bacillus atropheus subsp. globigii for which we use the spores as internal control in diagnostic assays. A total of 87 mismatched primers were tested in this study. We observed that target specific RPA primers with mismatches (n > 1) at their 3'extrimity hampered RPA reaction. In addition, 3 mismatches covering both extremities and the center of the primer sequence negatively affected RPA yield. We demonstrated that the specificity of RPA was multifactorial. Therefore its application in clinical settings must be selected and validated a priori. We recommend that the selection of a target gene must consider the presence of closely-related non-target genes. It is advisable to choose target regions with a high number of mismatches (≥36%, relative to the size of amplicon) with respect to closely-related species and the best case scenario would be by choosing a unique target gene.

  8. Nucleic acid sequence-based amplification with oligochromatography for detection of Trypanosoma brucei in clinical samples

    NARCIS (Netherlands)

    C.M. Mugasa; T. Laurent; G.J. Schoone; P.A. Kager; G.W. Lubega; H.D.F.H. Schallig


    Molecular tools, such as real-time nucleic acid sequence-based amplification (NASBA) and PCR, have been developed to detect Trypanosoma brucei parasites in blood for the diagnosis of human African trypanosomiasis (HAT). Despite good sensitivity, these techniques are not implemented in HAT control pr

  9. Multi-Terabit Long-Haul Transmission System Utilizing Distributed Raman Amplification Technologies

    Institute of Scientific and Technical Information of China (English)

    Takao Naito; Toshiki Tanaka


    Here we summarize multi-terabit long-haul transmission experiment and distributed Raman amplification (DRA) technologies. As well, we investigate the configuration of dispersion-managed fibers for the DRA-based system from the viewpoint of the fiber non-linear effect and required pumping power.

  10. Automated nucleic acid amplification testing in blood banks: An additional layer of blood safety

    Directory of Open Access Journals (Sweden)

    Pragati Chigurupati


    Full Text Available Context: A total of 30 million blood components are transfused each year in India. Blood safety thus becomes a top priority, especially with a population of around 1.23 billion and a high prevalence rate of human immunodeficiency virus (HIV, hepatitis B virus (HBV and hepatitis C virus (HCV in general population. Nucleic acid amplification testing (NAT in blood donor screening has been implemented in many developed countries to reduce the risk of transfusion-transmitted viral infections (TTIs. NAT takes care of the dynamics of window period of viruses and offers the safest blood pack for donation. Aims: The aim of this study is to show the value of NAT in blood screening. Settings and Design: Dhanavantari Blood Bank, Rajahmundry, Andhra Pradesh, India. Subjects and Methods: Over a period of 1 year from January 2012 to December 2012, a total number of 15,000 blood donor samples were subjected to tests for HIV, HBV, and HCV by enzyme-linked immunosorbent assay (ELISA method and 8000 ELISA nonreactive samples were subjected for NAT using multiplex polymerase chain reaction technology. Results: Of the 15,000 donors tested, 525 were seroreactive. In 8000 ELISA negative blood samples subjected to NAT, 4 donor samples were reactive for HBV. The NAT yield was 1 in 2000. Conclusions: NAT could detect HIV, HBV, and HCV cases in blood donor samples those were undetected by serological tests. NAT could interdict 2500 infectious donations among our approximate 5 million annual blood donations.

  11. Two-stage sample-to-answer system based on nucleic acid amplification approach for detection of malaria parasites. (United States)

    Liu, Qing; Nam, Jeonghun; Kim, Sangho; Lim, Chwee Teck; Park, Mi Kyoung; Shin, Yong


    Rapid, early, and accurate diagnosis of malaria is essential for effective disease management and surveillance, and can reduce morbidity and mortality associated with the disease. Although significant advances have been achieved for the diagnosis of malaria, these technologies are still far from ideal, being time consuming, complex and poorly sensitive as well as requiring separate assays for sample processing and detection. Therefore, the development of a fast and sensitive method that can integrate sample processing with detection of malarial infection is desirable. Here, we report a two-stage sample-to-answer system based on nucleic acid amplification approach for detection of malaria parasites. It combines the Dimethyl adipimidate (DMA)/Thin film Sample processing (DTS) technique as a first stage and the Mach-Zehnder Interferometer-Isothermal solid-phase DNA Amplification (MZI-IDA) sensing technique as a second stage. The system can extract DNA from malarial parasites using DTS technique in a closed system, not only reducing sample loss and contamination, but also facilitating the multiplexed malarial DNA detection using the fast and accurate MZI-IDA technique. Here, we demonstrated that this system can deliver results within 60min (including sample processing, amplification and detection) with high sensitivity (malaria in low-resource settings.

  12. Comparison of Three Nucleic Acid Amplification Assays of Cerebrospinal Fluid for Diagnosis of Cytomegalovirus Encephalitis (United States)

    Bestetti, Arabella; Pierotti, Chiara; Terreni, Mariarosa; Zappa, Alessandra; Vago, Luca; Lazzarin, Adriano; Cinque, Paola


    The diagnostic reliabilities of three cytomegalovirus (CMV) nucleic acid amplification assays of cerebrospinal fluid (CSF) were compared by using CSF samples from human immunodeficiency virus-infected patients with a postmortem histopathological diagnosis of CMV encephalitis (n = 15) or other central nervous system conditions (n = 16). By using a nested PCR assay, the quantitative COBAS AMPLICOR CMV MONITOR PCR, and the NucliSens CMV pp67 nucleic acid sequence-based amplification assay, sensitivities were 93.3, 86.6, and 93.3%, respectively, and specificities were 93.7, 93.7, and 87.5%, respectively. The COBAS AMPLICOR assay revealed significantly higher CMV DNA levels in patients with diffuse ventriculoencephalitis than in patients with focal periventricular lesions. PMID:11230445

  13. Application of Isothermal Amplification Technology in Molecular Diagnosis%恒温扩增技术在分子诊断中的应用

    Institute of Scientific and Technical Information of China (English)



    聚合酶链反应(PCR)技术是近年来广泛应用于科学研究和临床检验的一项技术.目前传统的PCR技术中核酸的扩增存在效率不高且需要专用的仪器设备等缺陷,而恒温扩增技术由于引物种类多样,检测方法多变,从而克服了传统PCR核酸扩增技术的缺点,使其越来越多地被应用于分子诊断中.经国内外学者的研究证实,恒温扩增技术有着广泛的应用前景,现着重对恒温扩增技术予以综述.%Polymerase chain reaction( PCR ) is a technology which is widely applied in scientific research and Clinical examination. At present, the conventional PCR employed by nucleic acid amplification has some shortcomings , surh as low efficiency , needing of special instrument ,etc. On the contrary, . the isothermal amplification methods have overcome these disadvantages by utilizing a rich variety of primers and testing methods. It is confirmed by domestic and oversea scholars that a wide range of medical applications of isothermal amplification technology is expected. Here is to provide an overview of isothermal amplification technology.

  14. An integrated portable hand-held analyser for real-time isothermal nucleic acid amplification. (United States)

    Smith, Matthew C; Steimle, George; Ivanov, Stan; Holly, Mark; Fries, David P


    A compact hand-held heated fluorometric instrument for performing real-time isothermal nucleic acid amplification and detection is described. The optoelectronic instrument combines a Printed Circuit Board/Micro Electro Mechanical Systems (PCB/MEMS) reaction detection/chamber containing an integrated resistive heater with attached miniature LED light source and photo-detector and a disposable glass waveguide capillary to enable a mini-fluorometer. The fluorometer is fabricated and assembled in planar geometry, rolled into a tubular format and packaged with custom control electronics to form the hand-held reactor. Positive or negative results for each reaction are displayed to the user using an LED interface. Reaction data is stored in FLASH memory for retrieval via an in-built USB connection. Operating on one disposable 3 V lithium battery >12, 60 min reactions can be performed. Maximum dimensions of the system are 150 mm (h) x 48 mm (d) x 40 mm (w), the total instrument weight (with battery) is 140 g. The system produces comparable results to laboratory instrumentation when performing a real-time nucleic acid sequence-based amplification (NASBA) reaction, and also displayed comparable precision, accuracy and resolution to laboratory-based real-time nucleic acid amplification instrumentation. A good linear response (R2 = 0.948) to fluorescein gradients ranging from 0.5 to 10 microM was also obtained from the instrument indicating that it may be utilized for other fluorometric assays. This instrument enables an inexpensive, compact approach to in-field genetic screening, providing results comparable to laboratory equipment with rapid user feedback as to the status of the reaction.

  15. Effect of nucleic acid binding dyes on DNA extraction, amplification, and STR typing. (United States)

    Haines, Alicia M; Tobe, Shanan S; Kobus, Hilton J; Linacre, Adrian


    We report on the effects of six dyes used in the detection of DNA on the process of DNA extraction, amplification, and detection of STR loci. While dyes can be used to detect the presence of DNA, their use is restricted if they adversely affect subsequent DNA typing processes. Diamond™ Nucleic Acid Dye, GelGreen™, GelRed™, RedSafe™, SYBR(®) Green I, and EvaGreen™ were evaluated in this study. The percentage of dye removed during the extraction process was determined to be: 70.3% for SYBR(®) Green I; 99.6% for RedSafe™; 99.4% for EvaGreen™; 52.7% for Diamond™ Dye; 50.6% for GelRed™, and; could not be determined for GelGreen™. It was then assumed that the amount of dye in the fluorescent quantification assay had no effect on the DNA signal. The presence of all six dyes was then reviewed for their effect on DNA extraction. The t-test showed no significant difference between the dyes and the control. These extracts were then STR profiled and all dyes and control produced full DNA profiles. STR loci in the presence of GelGreen(TM) at 1X concentration showed increased amplification products in comparison to the control samples. Full STR profiles were detected in the presence of EvaGreen™ (1X), although with reduced amplification products. RedSafe™ (1X), Diamond™ Dye (1X), and SYBR(®) Green I (1X) all exhibited varying degrees of locus drop-out with GelRed™ generating no loci at all. We provide recommendations for the best dye to visualize the presence of DNA profile as a biological stain and its subsequent amplification and detection.

  16. Detection of virus mRNA within infected host cells using an isothermal nucleic acid amplification assay: marine cyanophage gene expression within Synechococcus sp

    Directory of Open Access Journals (Sweden)

    Hall Matthew J


    Full Text Available Abstract Background Signal-Mediated Amplification of RNA Technology (SMART is an isothermal nucleic acid amplification technology, developed for the detection of specific target sequences, either RNA (for expression or DNA. Cyanophages are viruses that infect cyanobacteria. Marine cyanophages are ubiquitous in the surface layers of the ocean where they infect members of the globally important genus Synechococcus. Results Here we report that the SMART assay allowed us to differentiate between infected and non-infected host cultures. Expression of the cyanophage strain S-PM2 portal vertex gene (g20 was detected from infected host Synechococcus sp. WH7803 cells. Using the SMART assay, we demonstrated that g20 mRNA peaked 240 – 360 minutes post-infection, allowing us to characterise this as a mid to late transcript. g20 DNA was also detected, peaking 10 hours post-infection, coinciding with the onset of host lysis. Conclusion The SMART assay is based on isothermal nucleic acid amplification, allowing the detection of specific sequences of DNA or RNA. It was shown to be suitable for differentiating between virus-infected and non-infected host cultures and for the detection of virus gene expression: the first reported use of this technology for such applications.

  17. The origin of biased sequence depth in sequence-independent nucleic acid amplification and optimization for efficient massive parallel sequencing.

    Directory of Open Access Journals (Sweden)

    Toon Rosseel

    Full Text Available Sequence Independent Single Primer Amplification is one of the most widely used random amplification approaches in virology for sequencing template preparation. This technique relies on oligonucleotides consisting of a 3' random part used to prime complementary DNA synthesis and a 5' defined tag sequence for subsequent amplification. Recently, this amplification method was combined with next generation sequencing to obtain viral sequences. However, these studies showed a biased distribution of the resulting sequence reads over the analyzed genomes. The aim of this study was to elucidate the mechanisms that lead to biased sequence depth when using random amplification. Avian paramyxovirus type 8 was used as a model RNA virus to investigate these mechanisms. We showed, based on in silico analysis of the sequence depth in relation to GC-content, predicted RNA secondary structure and sequence complementarity to the 3' part of the tag sequence, that the tag sequence has the main contribution to the observed bias in sequence depth. We confirmed this finding experimentally using both fragmented and non-fragmented viral RNAs as well as primers differing in random oligomer length (6 or 12 nucleotides and in the sequence of the amplification tag. The observed oligonucleotide annealing bias can be reduced by extending the random oligomer sequence and by in silico combining sequence data from SISPA experiments using different 5' defined tag sequences. These findings contribute to the optimization of random nucleic acid amplification protocols that are currently required for downstream applications such as viral metagenomics and microarray analysis.

  18. Improved sensitivity of nucleic acid amplification for rapid diagnosis of tuberculous meningitis

    DEFF Research Database (Denmark)

    Johansen, Isik Somuncu; Lundgren, Bettina; Tabak, Fehmi


    Early diagnosis of tuberculous meningitis (TBM) is essential for a positive outcome; but present microbiological diagnostic techniques are insensitive, slow, or laborious. We evaluated the standard BDProbeTec ET strand displacement amplification method (the standard ProbeTec method) for the detec......Early diagnosis of tuberculous meningitis (TBM) is essential for a positive outcome; but present microbiological diagnostic techniques are insensitive, slow, or laborious. We evaluated the standard BDProbeTec ET strand displacement amplification method (the standard ProbeTec method......) for the detection of Mycobacterium tuberculosis complex organisms in parallel with the ProbeTec method with a modified pretreatment procedure with 101 prospectively collected cerebrospinal fluid specimens from 94 patients with suspected TBM. By the modified method, the sample-washing step was omitted. A definitive...... diagnosis was attained by culture. Thirteen specimens from 12 patients were culture positive for M. tuberculosis complex organisms; three specimens (23%) were microscopy positive for acid-fast bacilli. Among the culture-positive specimens, the standard ProbeTec method was positive for 8 (61...

  19. Ternary surface monolayers for ultrasensitive (zeptomole) amperometric detection of nucleic acid hybridization without signal amplification. (United States)

    Wu, Jie; Campuzano, Susana; Halford, Colin; Haake, David A; Wang, Joseph


    A ternary surface monolayer, consisting of coassembled thiolated capture probe, mercaptohexanol and dithiothreitol, is shown to offer dramatic improvements in the signal-to-noise characteristics of electrochemical DNA hybridization biosensors based on common self-assembled monolayers. Remarkably low detection limits down to 40 zmol (in 4 μL samples) as well as only 1 CFU Escherichia coli per sensor are thus obtained without any additional amplification step in connection to the commonly used horseradish peroxidase/3,3',5,5'-tetramethylbenzidine system. Such dramatic improvements in the detection limits (compared to those of common binary alkanethiol interfaces and to those of most electrochemical DNA sensing strategies without target or signal amplification) are attributed primarily to the remarkably higher resistance to nonspecific adsorption. This reflects the highly compact layer (with lower pinhole density) produced by the coupling of the cyclic- and linear-configuration "backfillers" that leads to a remarkably low background noise even in the presence of complex sample matrixes. A wide range of surface compositions have been investigated, and the ternary mixed monolayer has been systematically optimized. Detailed impedance spectroscopy and cyclic voltammetric studies shed useful insights into the surface coverage. The impressive sensitivity and high specificity of the simple developed methodology indicate great promise for a wide range of nucleic acid testing, including clinical diagnostics, biothreat detection, food safety, and forensic analysis.

  20. Review of 2005 Public Health Laboratory Network Neisseria gonorrhoeae nucleic acid amplification tests guidelines. (United States)

    Whiley, David M; Lahra, Monica M


    At the request of the Public Health Laboratory Network (PHLN), the National Neisseria Network (NNN) met to discuss the 2009 PHLN Neisseria gonorrhoeae nucleic acid amplification test (NAAT) guidelines and the need for supplementary testing. A central point of discussion at this NNN meeting, which took place in May 2013, was the potential for N. gonorrhoeae supplementary testing to lead to false-negative results. Data were presented at the meeting that questioned the sensitivity of commonly used in-house supplementary methods as compared with later generation commercial NAAT systems. It was the opinion of the NNN that supplementary testing remains best practice, but that caution should be used when reporting negative results. The NNN recommends that urogenital samples providing a positive result in a screening method and a negative result by a supplemental method should not be reported as negative for N. gonorrhoeae without an appropriate explanatory comment indicating that gonococcal infection cannot be excluded.

  1. Advances in isothermal amplification: novel strategies inspired by biological processes. (United States)

    Li, Jia; Macdonald, Joanne


    Nucleic acid amplification is an essential process in biological systems. The in vitro adoption of this process has resulted in powerful techniques that underpin modern molecular biology. The most common tool is polymerase chain reaction (PCR). However, the requirement for a thermal cycler has somewhat limited applications of this classic nucleic acid amplification technique. Isothermal amplification, on the other hand, obviates the use of a thermal cycler because reactions occur at a single temperature. Isothermal amplification methods are diverse, but all have been developed from an understanding of natural nucleic acid amplification processes. Here we review current isothermal amplification methods as classified by their enzymatic mechanisms. We compare their advantages, disadvantages, efficiencies, and applications. Finally, we mention some new developments associated with this technology, and consider future possibilities in molecular engineering and recombinant technologies that may develop from an appreciation of the molecular biology of natural systems.

  2. Culture confirmation of gonococcal infection by recall of subjects found to be positive by nucleic acid amplification tests in general practice

    DEFF Research Database (Denmark)

    Møller, Jens Kjølseth


    To evaluate a routine notification of general practitioners to recall nucleic acid amplification test (NAAT)-positive subjects for culture of Neisseria gonorrhoeae to confirm gonococcal infection in the community.......To evaluate a routine notification of general practitioners to recall nucleic acid amplification test (NAAT)-positive subjects for culture of Neisseria gonorrhoeae to confirm gonococcal infection in the community....

  3. Immunocytochemistry versus nucleic acid amplification in fine needle aspirates and tissues of extrapulmonary tuberculosis

    Directory of Open Access Journals (Sweden)

    Madhu Mati Goel


    Full Text Available Background: Immunocytochemistry (ICC is an established routine diagnostic adjunct to cytology and histology for tumor diagnosis but has received little attention for diagnosis of tuberculosis. Aims: To have an objective method of direct visualization of mycobacteria or their products in clinical extrapulmonary tuberculosis (EPTB specimens, immunocytochemical localization of M. tuberculosis antigen by staining with species specific monoclonal antibody to 38-kDa antigen of Mycobacterium tuberculosis complex. Materials and Methods: Immunostaining with specific monoclonal antibody to 38-kDa antigen of Mycobacterium tuberculosis complex was done in fresh and archival fine needle aspirates and tissue granulomata of 302 cases of extrapulmonary tuberculosis and was compared with the molecular diagnostic i.e., nucleic amplification and conventional [Cytomorphology, Ziehl Neelsen (ZN staining and culture] tests and 386 controls. Results: Diagnostic indices by Bayesian analysis for all types of archival and fresh material varied from 64 to 76% in nucleic acid amplification (NAA and 96 to 98% in ICC. There was no significant difference in the diagnostic indices of ZN staining and/ or ICC in fresh or archival material whereas the sensitivity of NAA differed significantly in fresh versus archival material both in cytology (71.4% vs 52.1% and histology (51.1% vs 38.8%. ICC can be easily used on archival smears and formalin-fixed paraffin-embedded tissue sections with almost equal sensitivity and specificity as with fresh material, in contrast to NAA which showed significant difference in test results on archival and fresh material. Conclusions: Low detection sensitivity of MTB DNA in archival material from known tuberculous cases showed the limitation of in-house NAA-based molecular diagnosis. ICC was found to be sensitive, specific and a better technique than NAA and can be used as an adjunct to conventional morphology and ZN staining for the diagnosis of

  4. Enhanced nucleic acid amplification with blood in situ by wire-guided droplet manipulation (WDM). (United States)

    Harshman, Dustin K; Reyes, Roberto; Park, Tu San; You, David J; Song, Jae-Young; Yoon, Jeong-Yeol


    There are many challenges facing the use of molecular biology to provide pertinent information in a timely, cost effective manner. Wire-guided droplet manipulation (WDM) is an emerging format for conducting molecular biology with unique characteristics to address these challenges. To demonstrate the use of WDM, an apparatus was designed and assembled to automate polymerase chain reaction (PCR) on a reprogrammable platform. WDM minimizes thermal resistance by convective heat transfer to a constantly moving droplet in direct contact with heated silicone oil. PCR amplification of the GAPDH gene was demonstrated at a speed of 8.67 s/cycle. Conventional PCR was shown to be inhibited by the presence of blood. WDM PCR utilizes molecular partitioning of nucleic acids and other PCR reagents from blood components, within the water-in-oil droplet, to increase PCR reaction efficiency with blood in situ. The ability to amplify nucleic acids in the presence of blood simplifies pre-treatment protocols towards true point-of-care diagnostic use. The 16s rRNA hypervariable regions V3 and V6 were amplified from Klebsiella pneumoniae genomic DNA with blood in situ. The detection limit of WDM PCR was 1 ng/μL or 10(5)genomes/μL with blood in situ. The application of WDM for rapid, automated detection of bacterial DNA from whole blood may have an enormous impact on the clinical diagnosis of infections in bloodstream or chronic wound/ulcer, and patient safety and morbidity.

  5. Entropy Beacon: A Hairpin-Free DNA Amplification Strategy for Efficient Detection of Nucleic Acids. (United States)

    Lv, Yifan; Cui, Liang; Peng, Ruizi; Zhao, Zilong; Qiu, Liping; Chen, Huapei; Jin, Cheng; Zhang, Xiao-Bing; Tan, Weihong


    Here, we propose an efficient strategy for enzyme- and hairpin-free nucleic acid detection called an entropy beacon (abbreviated as Ebeacon). Different from previously reported DNA hybridization/displacement-based strategies, Ebeacon is driven forward by increases in the entropy of the system, instead of free energy released from new base-pair formation. Ebeacon shows high sensitivity, with a detection limit of 5 pM target DNA in buffer and 50 pM in cellular homogenate. Ebeacon also benefits from the hairpin-free amplification strategy and zero-background, excellent thermostability from 20 °C to 50 °C, as well as good resistance to complex environments. In particular, based on the huge difference between the breathing rate of a single base pair and two adjacent base pairs, Ebeacon also shows high selectivity toward base mutations, such as substitution, insertion, and deletion and, therefore, is an efficient nucleic acid detection method, comparable to most reported enzyme-free strategies.

  6. Simple, rapid and accurate molecular diagnosis of acute promyelocytic leukemia by loop mediated amplification technology. (United States)

    Spinelli, Orietta; Rambaldi, Alessandro; Rigo, Francesca; Zanghì, Pamela; D'Agostini, Elena; Amicarelli, Giulia; Colotta, Francesco; Divona, Mariadomenica; Ciardi, Claudia; Coco, Francesco Lo; Minnucci, Giulia


    The diagnostic work-up of acute promyelocytic leukemia (APL) includes the cytogenetic demonstration of the t(15;17) translocation and/or the PML-RARA chimeric transcript by RQ-PCR or RT-PCR. This latter assays provide suitable results in 3-6 hours. We describe here two new, rapid and specific assays that detect PML-RARA transcripts, based on the RT-QLAMP (Reverse Transcription-Quenching Loop-mediated Isothermal Amplification) technology in which RNA retrotranscription and cDNA amplification are carried out in a single tube with one enzyme at one temperature, in fluorescence and real time format. A single tube triplex assay detects bcr1 and bcr3 PML-RARA transcripts along with GUS housekeeping gene. A single tube duplex assay detects bcr2 and GUSB. In 73 APL cases, these assays detected in 16 minutes bcr1, bcr2 and bcr3 transcripts. All 81 non-APL samples were negative by RT-QLAMP for chimeric transcripts whereas GUSB was detectable. In 11 APL patients in which RT-PCR yielded equivocal breakpoint type results, RT-QLAMP assays unequivocally and accurately defined the breakpoint type (as confirmed by sequencing). Furthermore, RT-QLAMP could amplify two bcr2 transcripts with particularly extended PML exon 6 deletions not amplified by RQ-PCR. RT-QLAMP reproducible sensitivity is 10(-3) for bcr1 and bcr3 and 10(-)2 for bcr2 thus making this assay particularly attractive at diagnosis and leaving RQ-PCR for the molecular monitoring of minimal residual disease during the follow up. In conclusion, PML-RARA RT-QLAMP compared to RT-PCR or RQ-PCR is a valid improvement to perform rapid, simple and accurate molecular diagnosis of APL.

  7. Picoliter Well Array Chip-Based Digital Recombinase Polymerase Amplification for Absolute Quantification of Nucleic Acids (United States)

    Li, Zhao; Liu, Yong; Wei, Qingquan; Liu, Yuanjie; Liu, Wenwen; Zhang, Xuelian; Yu, Yude


    Absolute, precise quantification methods expand the scope of nucleic acids research and have many practical applications. Digital polymerase chain reaction (dPCR) is a powerful method for nucleic acid detection and absolute quantification. However, it requires thermal cycling and accurate temperature control, which are difficult in resource-limited conditions. Accordingly, isothermal methods, such as recombinase polymerase amplification (RPA), are more attractive. We developed a picoliter well array (PWA) chip with 27,000 consistently sized picoliter reactions (314 pL) for isothermal DNA quantification using digital RPA (dRPA) at 39°C. Sample loading using a scraping liquid blade was simple, fast, and required small reagent volumes (i.e., <20 μL). Passivating the chip surface using a methoxy-PEG-silane agent effectively eliminated cross-contamination during dRPA. Our creative optical design enabled wide-field fluorescence imaging in situ and both end-point and real-time analyses of picoliter wells in a 6-cm2 area. It was not necessary to use scan shooting and stitch serial small images together. Using this method, we quantified serial dilutions of a Listeria monocytogenes gDNA stock solution from 9 × 10-1 to 4 × 10-3 copies per well with an average error of less than 11% (N = 15). Overall dRPA-on-chip processing required less than 30 min, which was a 4-fold decrease compared to dPCR, requiring approximately 2 h. dRPA on the PWA chip provides a simple and highly sensitive method to quantify nucleic acids without thermal cycling or precise micropump/microvalve control. It has applications in fast field analysis and critical clinical diagnostics under resource-limited settings. PMID:27074005

  8. Picoliter Well Array Chip-Based Digital Recombinase Polymerase Amplification for Absolute Quantification of Nucleic Acids. (United States)

    Li, Zhao; Liu, Yong; Wei, Qingquan; Liu, Yuanjie; Liu, Wenwen; Zhang, Xuelian; Yu, Yude


    Absolute, precise quantification methods expand the scope of nucleic acids research and have many practical applications. Digital polymerase chain reaction (dPCR) is a powerful method for nucleic acid detection and absolute quantification. However, it requires thermal cycling and accurate temperature control, which are difficult in resource-limited conditions. Accordingly, isothermal methods, such as recombinase polymerase amplification (RPA), are more attractive. We developed a picoliter well array (PWA) chip with 27,000 consistently sized picoliter reactions (314 pL) for isothermal DNA quantification using digital RPA (dRPA) at 39°C. Sample loading using a scraping liquid blade was simple, fast, and required small reagent volumes (i.e., PEG-silane agent effectively eliminated cross-contamination during dRPA. Our creative optical design enabled wide-field fluorescence imaging in situ and both end-point and real-time analyses of picoliter wells in a 6-cm(2) area. It was not necessary to use scan shooting and stitch serial small images together. Using this method, we quantified serial dilutions of a Listeria monocytogenes gDNA stock solution from 9 × 10(-1) to 4 × 10(-3) copies per well with an average error of less than 11% (N = 15). Overall dRPA-on-chip processing required less than 30 min, which was a 4-fold decrease compared to dPCR, requiring approximately 2 h. dRPA on the PWA chip provides a simple and highly sensitive method to quantify nucleic acids without thermal cycling or precise micropump/microvalve control. It has applications in fast field analysis and critical clinical diagnostics under resource-limited settings.

  9. 核酸扩增技术在病原体检测中的应用%Application of nucleic acid amplification in pathogen detection

    Institute of Scientific and Technical Information of China (English)

    范吉云; 郭晓奎; 李擎天


    传统的病原体检测方法在检测敏感性、特异性、应用范围等方面存在许多不足.PCR技术已被用于感染早期的病原体检测,但在应用过程中也面临不少问题.近年来出现的新的核酸扩增技术可弥补普通PCR技术的缺点.此文就其中依赖核酸序列的扩增技术、PCR-胶体金免疫层析技术和多重荧光实时PcR技术进行综述.%The traditional pathogen detection mathods have many disadvantages in the sensitivity, specificity and application range. There are still some problems in PCB, which has been used for pathogen detection in the early stage of infection. New nucleic acid amplification technologies may make up the deficiency of PCR. In this review, three methods including nucleic acid sequence-based amplification (NASBA), PCR-immunochromatography test and multiplex fluorescent real-time PCR technology are described.

  10. Early detection of Mycobacterium tuberculosis complex in BACTEC MGIT cultures using nucleic acid amplification. (United States)

    Lin, S Y; Hwang, S C; Yang, Y C; Wang, C F; Chen, Y H; Chen, T C; Lu, P L


    We evaluated the application of nucleic acid amplification (NAA) in liquid cultures for the early detection of Mycobacterium tuberculosis. The Cobas TaqMan MTB test, IS6110 real-time PCR, and hsp65 PCR-restriction fragment length polymorphism (RFLP) analysis were used to detect BACTEC MGIT 960 (MGIT) cultures on days 3, 5, 7, and 14. The procedure was initially tested with a reference strain, H37Rv (ATCC 27294). Subsequently, 200 clinical specimens, including 150 Acid Fast bacillus (AFB) smear-positive and 50 AFB smear-negative samples, were examined. The Cobas TaqMan MTB test and IS6110-based PCR analysis were able to detect M. tuberculosis after 1 day when the inoculum of H37Rv was >3 x 10(-2) CFU/ml. After a 5-day incubation in the MGIT system, all three NAA assays had a positive detection regardless of the inoculum size. After a 1-day incubation of the clinical specimens in the MGIT system, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the Cobas TaqMan MTB assay were 70.2%, 100%, 100%, and 82.3% respectively. For IS6110-based PCR analysis, these values were 63.1%, 100%, 100%, and 78.9%, and were 88.1%, 100%, 100%, and 92.1% respectively for hsp65 PCR-RFLP analysis. After a 3-day incubation, the specificity and PPV were 100% for all three NAA tests; the Cobas TaqMan MTB assay had the best sensitivity (97.6%) and NPV (98.3%). The sensitivity, specificity, PPV, and NPV for conventional culture analysis were 98.8%, 100%, 100%, and 99.1%. Thus, NAA may be useful for the early detection of M. tuberculosis after 3 days in MGIT.

  11. Loop-Mediated Isothermal Amplification (LAMP): Emergence As an Alternative Technology for Herbal Medicine Identification. (United States)

    Li, Jing-Jian; Xiong, Chao; Liu, Yue; Liang, Jun-Song; Zhou, Xing-Wen


    Correct identification of medicinal plant ingredients is essential for their safe use and for the regulation of herbal drug supply chain. Loop-mediated isothermal amplification (LAMP) is a recently developed approach to identify herbal medicine species. This novel molecular biology technique enables timely and accurate testing, especially in settings where infrastructures to support polymerase chain reaction facilities are lacking. Studies that used this method have altered our view on the extent and complexity of herbal medicine identification. In this review, we give an introduction into LAMP analysis, covers the basic principles and important aspects in the development of LAMP analysis method. Then we presented a critical review of the application of LAMP-based methods in detecting and identifying raw medicinal plant materials and their processed products. We also provide a practical standard operating procedure (SOP) for the utilization of the LAMP protocol in herbal authentication, and consider the prospects of LAMP technology in the future developments of herbal medicine identification and the challenges associated with its application.

  12. Multiplex, rapid and sensitive isothermal detection of nucleic-acid sequence by endonuclease restriction-mediated real-time multiple cross displacement amplification

    Directory of Open Access Journals (Sweden)

    Yi eWang


    Full Text Available We have devised a novel isothermal amplification technology, termed endonuclease restriction-mediated real-time multiple cross displacement amplification (ET-MCDA, which facilitated multiplex, rapid, specific and sensitive detection of nucleic-acid sequences at a constant temperature. The ET-MCDA integrated multiple cross displacement amplification strategy, restriction endonuclease cleavage and real-time fluorescence detection technique. In the ET-MCDA system, the functional cross primer E-CP1 or E-CP2 was constructed by adding a short sequence at the 5’ end of CP1 or CP2, respectively, and the new E-CP1 or E-CP2 primer was labelled at the 5’ end with a fluorophore and in the middle with a dark quencher. The restriction endonuclease Nb.BsrDI specifically recognized the short sequence and digested the newly synthesized double-stranded terminal sequences (5’ end short sequences and their complementary sequences, which released the quenching, resulting on a gain of fluorescence signal. Thus, the ET-MCDA allowed real-time detection of single or multiple targets in only a single reaction, and the positive results were observed in as short as 12 minutes, detecting down to 3.125 fg of genomic DNA per tube. Moreover, the analytical specificity and the practical application of the ET-MCDA were also successfully evaluated in this study. Here we provided the details on the novel ET-MCDA technique and expounded the basic ET-MCDA amplification mechanism.

  13. Successful Combination of Nucleic Acid Amplification Test Diagnostics and Targeted Deferred Neisseria gonorrhoeae Culture. (United States)

    Wind, Carolien M; de Vries, Henry J C; Schim van der Loeff, Maarten F; Unemo, Magnus; van Dam, Alje P


    Nucleic acid amplification tests (NAATs) are recommended for the diagnosis of N. gonorrhoeae infections because of their superior sensitivity. Increasing NAAT use causes a decline in crucial antimicrobial resistance (AMR) surveillance data, which rely on culture. We analyzed the suitability of the ESwab system for NAAT diagnostics and deferred targeted N. gonorrhoeae culture to allow selective and efficient culture based on NAAT results. We included patients visiting the STI Clinic Amsterdam, The Netherlands, in 2013. Patient characteristics and urogenital and rectal samples for direct N. gonorrhoeae culture, standard NAAT, and ESwab were collected. Standard NAAT and NAAT on ESwab samples were performed using the Aptima Combo 2 assay for N. gonorrhoeae and C. trachomatis. Two deferred N. gonorrhoeae cultures were performed on NAAT-positive ESwab samples after storage at 4°C for 1 to 3 days. We included 2,452 samples from 1,893 patients. In the standard NAAT, 107 samples were N. gonorrhoeae positive and 284 were C. trachomatis positive. The sensitivities of NAAT on ESwab samples were 83% (95% confidence interval [CI], 75 to 90%) and 87% (95% CI, 82 to 90%), respectively. ESwab samples were available for 98 of the gonorrhea-positive samples. Of these, 82% were positive in direct culture and 69% and 56% were positive in the 1st and 2nd deferred cultures, respectively (median storage times, 27 and 48 h, respectively). Deferred culture was more often successful in urogenital samples or when the patient had symptoms at the sampling site. Deferred N. gonorrhoeae culture of stored ESwab samples is feasible and enables AMR surveillance. To limit the loss in NAAT sensitivity, we recommend obtaining separate samples for NAAT and deferred culture.

  14. A sensitive SERS assay for detecting proteins and nucleic acids using a triple-helix molecular switch for cascade signal amplification. (United States)

    Ye, Sujuan; Wu, Yanying; Zhang, Wen; Li, Na; Tang, Bo


    A novel surface-enhanced Raman scattering (SERS) detection system is developed for proteins and nucleic acids based on a triple-helix molecular switch for multiple cycle signal amplification, achieving high sensitivity, universality, rapid analysis, and high selectivity.


    Discussed are acid rain control options available to the electric utility industry. They include coal switching, flue gas desulfurization, and such emerging lower cost technologies as Limestone Injection Multistage Burners (LIMB) and Advanced Silicate (ADVACATE), both developed ...

  16. Rapid Point-of-Care Isothermal Amplification Assay for the Detection of Malaria without Nucleic Acid Purification. (United States)

    Modak, Sayli S; Barber, Cheryl A; Geva, Eran; Abrams, William R; Malamud, Daniel; Ongagna, Yhombi Serge Yvon


    Malaria remains one of the most prevalent infectious diseases and results in significant mortality. Isothermal amplification (loop-mediated isothermal amplification) is used to detect malarial DNA at levels of ~1 parasite/µL blood in ≤30 minutes without the isolation of parasite nucleic acid from subject's blood or saliva. The technique targets the mitochondrial cytochrome oxidase subunit 1 gene and is capable of distinguishing Plasmodium falciparum from Plasmodium vivax. Malarial diagnosis by the gold standard microscopic examination of blood smears is generally carried out only after moderate-to-severe symptoms appear. Rapid diagnostic antigen tests are available but generally require infection levels in the range of 200-2,000 parasites/µL for a positive diagnosis and cannot distinguish if the disease has been cleared due to the persistence of circulating antigen. This study describes a rapid and simple molecular assay to detect malarial genes directly from whole blood or saliva without DNA isolation.

  17. Detection of Salmonella invA by isothermal and chimeric primer-initiated amplification of nucleic acids (ICAN) in Zambia. (United States)

    Isogai, Emiko; Makungu, Chitwambi; Yabe, John; Sinkala, Patson; Nambota, Andrew; Isogai, Hiroshi; Fukushi, Hideto; Silungwe, Manda; Mubita, Charles; Syakalima, Michelo; Hang'ombe, Bernard Mudenda; Kozaki, Shunji; Yasuda, Jun


    The isothermal and chimeric primer-initiated amplification of nucleic acids (ICAN) is a new isothermal DNA amplification method composed of exo Bca DNA polymerase, RNaseH and DNA-RNA chimeric primers. We detected invA of Salmonella from chicken carcasses, egg yolk and cattle fecal samples. Fifty-three of 59 isolates were invA-positive in ICAN-chromatostrip detection. The result was consistent with those obtained by standard PCR. Salmonella invA was detected in 12 of 14 carcass rinses by ICAN, while in 7 of 14 rinses by standard PCR. These results indicate that ICAN is an efficient, sensitive and simple system to detect invA of Salmonella species in developing countries such as Zambia.

  18. Isothermal strand displacement amplification (iSDA): a rapid and sensitive method of nucleic acid amplification for point-of-care diagnosis. (United States)

    Toley, Bhushan J; Covelli, Isabela; Belousov, Yevgeniy; Ramachandran, Sujatha; Kline, Enos; Scarr, Noah; Vermeulen, Nic; Mahoney, Walt; Lutz, Barry R; Yager, Paul


    We present a method of rapid isothermal amplification of DNA without initial heat denaturation of the template, and methods and probes for (a) real-time fluorescence detection and (b) lateral flow detection of amplicons. Isothermal strand displacement amplification (iSDA) can achieve >10(9)-fold amplification of the target sequence in isothermal DNA amplification methods. iSDA initiates at sites where DNA base pairs spontaneously open or transiently convert into Hoogsteen pairs, i.e. "breathe", and proceeds to exponential amplification by repeated nicking, extension, and displacement of single strands. We demonstrate successful iSDA amplification and lateral flow detection of 10 copies of a Staphylococcus aureus gene, NO.-inducible l-lactate dehydrogenase (ldh1) (Richardson, Libby, and Fang, Science, 2008, 319, 1672-1676), in a clean sample and 50 copies in the presence of high concentrations of genomic DNA and mucins in isothermal amplification reactions. Finally, we demonstrate the multiplexing capability of iSDA by the simultaneous amplification of the target gene and an engineered internal control sequence. The speed, sensitivity, and specificity of iSDA make it a powerful method for point-of-care molecular diagnosis.

  19. Diagnostic value of nine nucleic acid amplification test systems for Mycobacterium tuberculosis complex

    Directory of Open Access Journals (Sweden)

    Gülnur Tarhan


    Full Text Available Objective: In this study, nine commercial Nucleic Acid Amplification Test Systems (NAATs were evaluated for diagnostic performance of Mycobacterium tuberculosis complex (MTBC from smear positive sputum species (SPss and smear negative sputum specimens (SNss. Methods: Sixty SPss and 55 SNss were examined icroscopically by Ehrlich Ziehl Neelsen (EZN staining method, and also inoculated on Löwenstein Jensen (LJ medium for culture. The sensitivity and specificity of nine NAATs were calculated according to LJ culture method accepted as gold standard. Results: When LJ culture results were taken as gold standard; the sensitivity rates of method COBAS Amplicor MTB (Method A, GenProbe MTD (Method B, Cobas TaqMan MTB PCR Method C, iCycler iQ RT PCR (Method D, TaqMan PCR AB 5700 (Method E, TaqMan PCR AB7700 (Method F, ightCycler® 480 RT PCR (Method G, Rotor Gene RT PCR (Method H and the AdvanSure TB/NTM RT PCR (Method I for SPss were 98.3 %, 93.3 %, 96.7 %, 100 %, 93.3 %, 100 %, 100 %, 100 % and 100 %, respectively. The sensitivity was 53.84% for the methods A, B, D, E, G and I; 38.46% for the method C and H; 61.5% for the method F for the method I in SNss. There were no statistical significant differences between the nine NAATs (p≥0.05. The specificity was 100% for all nine NAATs in SNss. The positivity rates of methods were 53.8% for methods A, B, D, E, G, I; 38.5% for methods C and H, and 61.5% for method F in SNss. These rates were 100% for D, F, G, H and I; 98.3% for method A; 96.7% for method C; 93,3% for methods B and E in SPss. Statistical analysis showed that there was no statistically significant differences among the nine NAATs (p≥0.05. Conclusion: It is concluded that the nine NAATs might be useful for detecting MTBC from SPss, but not effective for SNss. J Microbiol Infect Dis 2015;5(3: 103-109

  20. Nucleic acid specific-based amplification and its application in inspection and quarantine%NASBA技术及其在检验检疫中的应用

    Institute of Scientific and Technical Information of China (English)

    王英超; 王宁宁; 吴兴海; 陈长法; 魏晓棠; 封立平; 张成标


    Nucleic acid specific-based amplification (NASBA) is a new technology to amplify RNA originated in PCR. As a new research means, NASBA has the characteristics of convenience, good accuracy, high sensitivity and short periods, especially applicable to RNA analysis. The nucleic acid analysis technology is an important means in entry-exit inspection and quarantine, which can be used to detect and identify pathogenic microorganism in food, pests and pathogen in animals and plants. The paper briefly introduced basic principle of NASBA, compared NASBA to RT-PCR, realtime RT-PCR and other isothermal amplification methods and revealed their differences and similarity. According to the usage characteristics of NASBA, the paper reviewed the application and prospect of NASBA in food safety detection and animal and plant quarantine in entry-exit inspection and quarantine.%序列特异性核酸体外扩增技术(nucleic acid specific-based amplification, NASBA)是在PCR基础上发展起来的一种扩增RNA的新技术,作为一种新型研究手段,具有便捷、准确性好、灵敏度高、周期短的特点,尤其适用于RNA的分析研究。核酸分析技术是出入境检验检疫工作的重要手段,可用于食品病原微生物、动植物产品中的有害生物、病原的分析及鉴定。本文简要介绍了NASBA技术的基本原理,在论证对比NASBA技术与普通PCR方法、荧光PCR方法及其他恒温扩增等核酸分析技术的差异及相似性后,根据其使用特点进一步对NASBA在进出境检验检疫的食品安全检测及动植物检疫的应用予以综述及展望。

  1. Locked nucleic acid inhibits amplification of contaminating DNA in real-time PCR

    DEFF Research Database (Denmark)

    Hummelshoj, Lone; Ryder, Lars P; Madsen, Hans O


    and real-time PCR, the addition of LNA showed blocking of the amplification of genomic XBP1 but not cDNA XBP1. To test the effect of melting temperature (Tm) on the LNA, we investigated the number of LNA nucleotides that could be replaced with DNA nucleotides and still retain the blocking activity. More...

  2. Phosphoric Acid Fuel Cell Technology Status (United States)

    Simons, S. N.; King, R. B.; Prokopius, P. R.


    A review of the current phosphoric acid fuel cell system technology development efforts is presented both for multimegawatt systems for electric utility applications and for multikilowatt systems for on-site integrated energy system applications. Improving fuel cell performance, reducing cost, and increasing durability are the technology drivers at this time. Electrodes, matrices, intercell cooling, bipolar/separator plates, electrolyte management, and fuel selection are discussed.

  3. Label-free electrochemical nucleic acid biosensing by tandem polymerization and cleavage-mediated cascade target recycling and DNAzyme amplification. (United States)

    Liu, Shufeng; Gong, Hongwei; Wang, Yanqun; Wang, Li


    Owing to the intrinsic importance of nucleic acid as bio-targets, the achievement of its simple and sensitive detection with high confidence is very essential for biological studies and diagnostic purposes. Herein, a label-free, isothermal, and ultrasensitive electrochemical detection of target DNA was developed by using a tandem polymerization and cleavage-mediated cascade target recycling and DNAzyme releasing amplification strategy. Upon sensing of the nucleic acid analyte for the assembled hairpin-like probe DNA on the electrode, the DNA polymerase guided the target recycling and simultaneously triggered the lambda exonuclease cleavage, accompanied by the cascade recycling of the released new complementary strand and the amplified liberation of the G-rich sequence of the HRP-mimicking DNAzyme. The electrocatalytic reduction of H2O2 by the generated hemin/G-quadruplex DNAzyme was used for the signal readout and further amplification toward target response. Such tandem functional operation by DNA polymerase, lambda exonuclease and DNAzyme endows the developed biosensor with a high sensitivity and also a high confidence. A low detection limit of 5 fM with an excellent selectivity toward target DNA could be achieved. It also exhibits the distinct advantages of simplicity in probe design and biosensor fabrication, and label-free electrochemical detection, thus may offer a promising avenue for the applications in disease diagnosis and clinical biomedicine.

  4. Chip-based device for parallel sorting, amplification, detection, and identification of nucleic acid subsequences

    Energy Technology Data Exchange (ETDEWEB)

    Beer, Neil Reginald; Colston, Jr, Billy W.


    An apparatus for chip-based sorting, amplification, detection, and identification of a sample having a planar substrate. The planar substrate is divided into cells. The cells are arranged on the planar substrate in rows and columns. Electrodes are located in the cells. A micro-reactor maker produces micro-reactors containing the sample. The micro-reactor maker is positioned to deliver the micro-reactors to the planar substrate. A microprocessor is connected to the electrodes for manipulating the micro-reactors on the planar substrate. A detector is positioned to interrogate the sample contained in the micro-reactors.

  5. On-Chip Isothermal Nucleic Acid Amplification on Flow-Based Chemiluminescence Microarray Analysis Platform for the Detection of Viruses and Bacteria. (United States)

    Kunze, A; Dilcher, M; Abd El Wahed, A; Hufert, F; Niessner, R; Seidel, M


    This work presents an on-chip isothermal nucleic acid amplification test (iNAAT) for the multiplex amplification and detection of viral and bacterial DNA by a flow-based chemiluminescence microarray. In a principle study, on-chip recombinase polymerase amplification (RPA) on defined spots of a DNA microarray was used to spatially separate the amplification reaction of DNA from two viruses (Human adenovirus 41, Phi X 174) and the bacterium Enterococcus faecalis, which are relevant for water hygiene. By establishing the developed assay on the microarray analysis platform MCR 3, the automation of isothermal multiplex-amplification (39 °C, 40 min) and subsequent detection by chemiluminescence imaging was realized. Within 48 min, the microbes could be identified by the spot position on the microarray while the generated chemiluminescence signal correlated with the amount of applied microbe DNA. The limit of detection (LOD) determined for HAdV 41, Phi X 174, and E. faecalis was 35 GU/μL, 1 GU/μL, and 5 × 10(3) GU/μL (genomic units), which is comparable to the sensitivity reported for qPCR analysis, respectively. Moreover the simultaneous amplification and detection of DNA from all three microbes was possible. The presented assay shows that complex enzymatic reactions like an isothermal amplification can be performed in an easy-to-use experimental setup. Furthermore, iNAATs can be potent candidates for multipathogen detection in clinical, food, or environmental samples in routine or field monitoring approaches.

  6. BNL Citric Acid Technology: Pilot Scale Demonstration

    Energy Technology Data Exchange (ETDEWEB)



    The objective of this project is to remove toxic metals such as lead and cadmium from incinerator ash using the Citric Acid Process developed at Brookhaven National Laboratory. In this process toxic metals in bottom ash from the incineration of municipal solid waste were first extracted with citric acid followed by biodegradation of the citric acid-metal extract by the bacterium Pseudomonas fluorescens for metals recovery. The ash contained the following metals: Al, As, Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Se, Sr, Ti, and Zn. Optimization of the Citric Acid Process parameters which included citric acid molarity, contact time, the impact of mixing aggressiveness during extraction and pretreatment showed lead and cadmium removal from incinerator ash of >90%. Seeding the treated ash with P. fluorescens resulted in the removal of residual citric acid and biostabilization of any leachable lead, thus allowing it to pass EPA?s Toxicity Characteristic Leaching Procedure. Biodegradation of the citric acid extract removed >99% of the lead from the extract as well as other metals such as Al, Ca, Cu, Fe, Mg, Mn, Ti, and Zn. Speciation of the bioprecipitated lead by Extended X-ray Absorption Fine Structure at the National Synchrotron Light Source showed that the lead is predominantly associated with the phosphate and carboxyl functional groups in a stable form. Citric acid was completely recovered (>99%) from the extract by sulfide precipitation technique and the extraction efficiency of recovered citric acid is similar to that of the fresh citric acid. Recycling of the citric acid should result in considerable savings in the overall treatment cost. We have shown the potential application of this technology to remove and recover the metal contaminants from incinerator ash as well as from other heavy metal bearing wastes (i.e., electric arc furnace dust from steel industry) or soils. Information developed from this project is being applied to demonstrate the remediation of

  7. Nucleic acid amplification tests in the diagnosis of tuberculous pleuritis: a systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    Riley Lee W


    Full Text Available Abstract Background Conventional tests for tuberculous pleuritis have several limitations. A variety of new, rapid tests such as nucleic acid amplification tests – including polymerase chain reaction – have been evaluated in recent times. We conducted a systematic review to determine the accuracy of nucleic acid amplification (NAA tests in the diagnosis of tuberculous pleuritis. Methods A systematic review and meta-analysis of 38 English and Spanish articles (with 40 studies, identified via searches of six electronic databases, hand searching of selected journals, and contact with authors, experts, and test manufacturers. Sensitivity, specificity, and other measures of accuracy were pooled using random effects models. Summary receiver operating characteristic curves were used to summarize overall test performance. Heterogeneity in study results was formally explored using subgroup analyses. Results Of the 40 studies included, 26 used in-house ("home-brew" tests, and 14 used commercial tests. Commercial tests had a low overall sensitivity (0.62; 95% confidence interval [CI] 0.43, 0.77, and high specificity (0.98; 95% CI 0.96, 0.98. The positive and negative likelihood ratios for commercial tests were 25.4 (95% CI 16.2, 40.0 and 0.40 (95% CI 0.24, 0.67, respectively. All commercial tests had consistently high specificity estimates; the sensitivity estimates, however, were heterogeneous across studies. With the in-house tests, both sensitivity and specificity estimates were significantly heterogeneous. Clinically meaningful summary estimates could not be determined for in-house tests. Conclusions Our results suggest that commercial NAA tests may have a potential role in confirming (ruling in tuberculous pleuritis. However, these tests have low and variable sensitivity and, therefore, may not be useful in excluding (ruling out the disease. NAA test results, therefore, cannot replace conventional tests; they need to be interpreted in parallel

  8. Non-instrumented nucleic acid amplification (NINA): instrument-free molecular malaria diagnostics for low-resource settings. (United States)

    Labarre, Paul; Gerlach, Jay; Wilmoth, Jared; Beddoe, Andrew; Singleton, Jered; Weigl, Bernhard


    We have achieved the first complete, non-instrumented nucleic acid amplification test (NAAT) using a calcium oxide heat source thermally linked to an engineered phase change material. These two components alone maintain a thermal profile suitable for the loop-mediated isothermal amplification assay. Starting with computational fluid dynamics analysis, we identified nominal geometry for the exothermic reaction chamber, phase change material chamber, thermal insulation, and packaging. Using this model, we designed and fabricated an alpha prototype assay platform. We have verified the function of this multi-pathogen-capable platform with both fluorescent and visual turbidity indications using samples spiked with malaria DNA. Both the exothermically heated platform samples and samples heated on a Perkin-Elmer GeneAmp9600 thermocycler were first incubated at 62°C for 45 minutes, then heated to 95°C to terminate enzyme activity, then analyzed. Results from the exothermically heated, non-instrumented platform were comparable to those from the thermocycler. These developments will enable point-of-care diagnostics using accurate NAATs which until now have required a well-equipped laboratory. The aim of this research is to provide pathogen detection with NAAT-level sensitivity in low-resource settings where assays such as immunochromatographic strip tests are successfully used but where there is no access to the infrastructure and logistics required to operate and maintain instrument-based diagnostics.

  9. A novel, sensitive and label-free loop-mediated isothermal amplification detection method for nucleic acids using luminophore dyes. (United States)

    Roy, Sharmili; Wei, Sim Xiao; Ying, Jean Liew Zhi; Safavieh, Mohammadali; Ahmed, Minhaz Uddin


    Electrochemiluminescence (ECL) has been widely rendered for nucleic acid testing. Here, we integrate loop-mediated isothermal amplification (LAMP) with ECL technique for DNA detection and quantification. The target LAMP DNA bound electrostatically with [Ru(bpy)3](+2) on the carbon electrode surface, and an ECL reaction was triggered by tripropylamine (TPrA) to yield luminescence. We illustrated this method as a new and highly sensitive strategy for the detection of sequence-specific DNA from different meat species at picogram levels. The proposed strategy renders the signal amplification capacities of TPrA and combines LAMP with inherently high sensitivity of the ECL technique, to facilitate the detection of low quantities of DNA. By leveraging this technique, target DNA of Sus scrofa (pork) meat was detected as low as 1pg/µL (3.43×10(-1)copies/µL). In addition, the proposed technique was applied for detection of Bacillus subtilis DNA samples and detection limit of 10pg/µL (2.2×10(3)copies/µL) was achieved. The advantages of being isothermal, sensitive and robust with ability for multiplex detection of bio-analytes makes this method a facile and appealing sensing modality in hand-held devices to be used at the point-of-care (POC).

  10. Acid-Breakable Resin-Based Chemical Amplification Positive Resist for Electron-Beam Mastering: Design and Lithographic Performance (United States)

    Sakamizu, Toshio; Shiraishi, Hiroshi


    A positive chemical amplification resist based on acid-catalyzed fragmentation of acetal groups in its main chain has been developed as a means of reducing line-edge roughness. The resist consists of an acid generator, an acid-diffusion controller and an acid-breakable (AB) resin that is synthesized through a co-condensation reaction between polyphenol and aromatic multifunctional vinylether compound. The effects of the fractionation of AB resins on resin properties and line-edge roughness (LER) are evaluated. Although AB resins have wide molecular weight distributions, the density of acetal groups in this AB resin is found to be almost constant except in the lower molecular weight components. The resist with a fractionated resin from which such components are removed provides high-resolution patterns (70-nm-wide pit) with fairly low LER. AFM analysis shows that the surface roughness (SR) of the resist with the fractionated resin is smaller than that of a resist using nonfractionated AB resin, and that the SR value is not altered throughout the range of exposure doses up to just below the start of dissolution. By using the fractionated AB resin, the AB resin-based resist (ABR) is capable of forming sub-100 nm L/S patterns with less than 5 nm of LER (3σ).

  11. Ultrasensitive detection of nucleic acids by template enhanced hybridization followed by rolling circle amplification and catalytic hairpin assembly. (United States)

    Song, Weiling; Zhang, Qiao; Sun, Wenbo


    An ultrasensitive protocol for fluorescent detection of DNA is designed by combining the template enhanced hybridization process (TEHP) with Rolling Circle Amplification (RCA) and Catalytic Hairpin Assembly (CHA), showing a remarkable amplification efficiency.

  12. Microsatellite loci in the tiger shark and cross-species amplification using pyrosequencing technology (United States)

    Mendes, Natália J.; Cruz, Vanessa P.; Ashikaga, Fernando Y.; Camargo, Sâmia M.; Oliveira, Claudio; Piercy, Andrew N.; Burgess, George H.; Coelho, Rui; Santos, Miguel N.; Foresti, Fausto


    The tiger shark (Galeocerdo cuvier) has a global distribution in tropical and warm temperate seas, and it is caught in numerous fisheries worldwide, mainly as bycatch. It is currently assessed as near threatened by the International Union for Conservation of Nature (IUCN) Red List. In this study, we identified nine microsatellite loci through next generation sequencing (454 pyrosequencing) using 29 samples from the western Atlantic. The genetic diversity of these loci were assessed and revealed a total of 48 alleles ranging from 3 to 7 alleles per locus (average of 5.3 alleles). Cross-species amplification was successful at most loci for other species such as Carcharhinus longimanus, C. acronotus and Alopias superciliosus. Given the potential applicability of genetic markers for biological conservation, these data may contribute to the population assessment of this and other species of sharks worldwide. PMID:27635306

  13. Development and implementation of real-time nucleic acid amplification for the detection of enterovirus infections in comparison to rapid culture of various clinical specimens

    NARCIS (Netherlands)

    van Doornum, G J J; Schutten, Martin; Voermans, J; Guldemeester, G J J; Niesters, H G M


    Several real-time PCR and nucleic acid sequence-based amplification (NASBA) primer pairs and a modified real-time PCR primer pair for the detection of enteroviruses were compared. The modified real-time PCR primer pair was evaluated on clinical samples in comparison with cell culture using the Magna

  14. Reliability of nucleic acid amplification methods for detection of Chlamydia trachomatis in urine: results of the first international collaborative quality control study among 96 laboratories

    NARCIS (Netherlands)

    R.P.A.J. Verkooyen (Roel); G.T. Noordhoek; P.E. Klapper; J. Reid; J. Schirm; G.M. Cleator; M. Ieven; G. Hoddevik


    textabstractThe first European Quality Control Concerted Action study was organized to assess the ability of laboratories to detect Chlamydia trachomatis in a panel of urine samples by nucleic acid amplification tests (NATs). The panel consisted of lyophilized urine samples, includ

  15. Implementation of Oral and Rectal Gonococcal and Chlamydial Nucleic Acid Amplification-Based Testing as a Component of Local Health Department Activities. (United States)

    Nall, Jennifer; Barr, Breona; McNeil, Candice J; Bachmann, Laura H


    From January 1, 2014, to May 31, 2015, 452 individuals received extragenital nucleic acid amplification-based Neisseria gonorrhoeae and Chlamydia trachomatis testing through public health venues. Seventy-four individuals (16%) tested positive for Neisseria gonorrhoeae and/or Chlamydia trachomatis at an extragenital site and 40 (54%) would not have been effectively diagnosed and treated in the absence of extragenital testing.

  16. Highly sensitive chemiluminescence technology for protein detection using aptamer-based rolling circle amplification platform

    Institute of Scientific and Technical Information of China (English)

    Zhi-Juan Cao; Qian-Wen Peng; Xue Qiu; Cai-Yun Liu; Jian-Zhong Lu


    A robust, selective and highly sensitive chemiluminescent (CL) platform for protein assay was presented in this paper. This novel CL approach utilized rolling circle amplification (RCA) as a signal enhancement technique and the 96-well plate as the immobilization and separation carrier. Typically, the antibody immobilized on the surface of 96-well plate was sandwiched with the protein target and the aptamer-primer sequence. This aptamer-primer sequence was then employed as the primer of RCA. Based on this design, a number of the biotinylated probes and streptavidin-horseradish peroxidase (SA-HRP) were captured on the plate, and the CL signal was amplified. In summary, our results demonstrated a robust biosensor with a detection limit of 10 fM that is easy to be established and utilized, and devoid of light source. Therefore, this new technique .will broaden the perspective for future development of DNA-based biosensors for the detection of other protein biomarkers related to clinical diseases, by taking advantages of high sensitivity and selectivity.

  17. Sugar-assisted kinetic resolution of amino acids and amplification of enantiomeric excess of organic molecules. (United States)

    Córdova, Armando; Sundén, Henrik; Xu, Yongmei; Ibrahem, Ismail; Zou, Weibiao; Engqvist, Magnus


    The origins of biological homochirality have intrigued researchers since Pasteur's discovery of the optical activity of biomolecules. Herein, we propose and demonstrate a novel alternative for the evolution of homochirality that is not based on autocatalysis and forges a direct relationship between the chirality of sugars and amino acids. This process provides a mechanism in which a racemic mixture of an amino acid can catalyze the formation of an optically active organic molecule in the presence of a sugar product of low enantiomeric excess.

  18. Detection of Staphylococcus epidermidis by a Quartz Crystal Microbalance Nucleic Acid Biosensor Array Using Au Nanoparticle Signal Amplification

    Directory of Open Access Journals (Sweden)

    Weiling Fu


    Full Text Available Staphylococcus epidermidis is a critical pathogen of nosocomial blood infections, resulting in significant morbidity and mortality. A piezoelectric quartz crystal microbalance (QCM nucleic acid biosensor array using Au nanoparticle signal amplification was developed to rapidly detect S. epidermidis in clinical samples. The synthesized thiolated probes specific targeting S. epidermidis 16S rRNA gene were immobilized on the surface of QCM nucleic acid biosensor arrays. Hybridization was induced by exposing the immobilized probes to the PCR amplified fragments of S. epidermidis, resulting in a mass change and a consequent frequency shift of the QCM biosensor. To further enhance frequency shift results from above described hybridizations, streptavidin coated Au nanoparticles were conjugated to the PCR amplified fragments. The results showed that the lowest detection limit of current QCM system was 1.3×103 CFU/mL. A linear correlation was found when the concentration of S. epidermidis varied from 1.3×103 to 1.3×107 CFU/mL. In addition, 55 clinical samples were detected with both current QCM biosensor system and conventional clinical microbiological method, and the sensitivity and specificity of current QCM biosensor system were 97.14% and 100%, respectively. In conclusion, the current QCM system is a rapid, low-cost and sensitive method that can be used to identify infection of S. epidermidis in clinical samples.

  19. Detection of microRNAs in frozen tissue sections by fluorescence in situ hybridization using locked nucleic acid probes and tyramide signal amplification. (United States)

    Silahtaroglu, Asli N; Nolting, Dorrit; Dyrskjøt, Lars; Berezikov, Eugene; Møller, Morten; Tommerup, Niels; Kauppinen, Sakari


    The ability to determine spatial and temporal microRNA (miRNA) accumulation at the tissue, cell and subcellular levels is essential for understanding the biological roles of miRNAs and miRNA-associated gene regulatory networks. This protocol describes a method for fast and effective detection of miRNAs in frozen tissue sections using fluorescence in situ hybridization (FISH). The method combines the unique miRNA recognition properties of locked nucleic acid (LNA)-modified oligonucleotide probes with FISH using the tyramide signal amplification (TSA) technology. Although both approaches have previously been shown to increase detection sensitivity in FISH, combining these techniques into one protocol significantly decreases the time needed for miRNA detection in cryosections, while simultaneously retaining high detection sensitivity. Starting with fixation of the tissue sections, this miRNA FISH protocol can be completed within approximately 6 h and allows miRNA detection in a wide variety of animal tissue cryosections as well as in human tumor biopsies at high cellular resolution.

  20. Nucleic acid amplification tests (NAATs for gonorrhoea diagnosis in women: Experience of a tertiary care hospital in north India

    Directory of Open Access Journals (Sweden)

    Seema Sood


    Full Text Available Background & objectives: Gonorrhoea is among the most frequent of the estimated bacterial sexually transmitted infections (STIs and has significant health implications in women. The use of nucleic acid amplification tests (NAATs has been shown to provide enhanced diagnosis of gonorrhoea in female patients. However, it is recommended that an on-going assessment of the test assays should be performed to check for any probable sequence variation occurring in the targeted region. In this study, an in-house PCR targeting opa-gene of Neisseria gonorrhoeae was used in conjunction with 16S ribosomal PCR to determine the presence of gonorrhoea in female patients attending the tertiary care hospitals. Methods: Endocervical samples collected from 250 female patients with complaints of vaginal or cervical discharge or pain in lower abdomen were tested using opa and 16S ribosomal assay. The samples were also processed by conventional methods. Results: Of the 250 female patients included in the study, only one was positive by conventional methods (microscopy and culture whereas 17 patients were found to be positive based on PCR results. Interpretation & conclusions: The clinical sensitivity of conventional methods for the detection of N. gonorrhoeae in female patients was low. The gonococcal detection rates increased when molecular method was used giving 16 additional positives. Studies should be done to find out other gene targets that may be used in the screening assays to detect the presence of gonorrhoea.

  1. Improved sensitivity of nucleic acid amplification for rapid diagnosis of tuberculous meningitis

    DEFF Research Database (Denmark)

    Johansen, Isik Somuncu; Lundgren, Bettina; Tabak, Fehmi;


    ) for the detection of Mycobacterium tuberculosis complex organisms in parallel with the ProbeTec method with a modified pretreatment procedure with 101 prospectively collected cerebrospinal fluid specimens from 94 patients with suspected TBM. By the modified method, the sample-washing step was omitted. A definitive...... diagnosis was attained by culture. Thirteen specimens from 12 patients were culture positive for M. tuberculosis complex organisms; three specimens (23%) were microscopy positive for acid-fast bacilli. Among the culture-positive specimens, the standard ProbeTec method was positive for 8 (61...... was adjusted from the recommended value of 3,400 to 1,000, the sensitivity of the modified procedure increased to 84.7%, with unchanged specificity. Results were obtained in 3 to 4 h. The new pretreatment procedure with the ProbeTec assay described here provides a rapid, simple, and sensitive tool...

  2. Quantitative nucleic acid amplification methods and their implications in clinical virology. (United States)

    Singh, Mini P; Galhotra, Shipra; Saigal, Karnika; Kumar, Archit; Ratho, Radha Kanta


    Recently, a number of techniques have been approved for quantification of viral nucleic acids in clinical samples. Viral load (VL) tests have considerable importance in the management of patients and are widely used in routine diagnosis. In clinical virology, VL testing are important to monitor the antiviral treatment, to initiate preemptive therapy, to understand pathogenesis, and to evaluate the infectivity. These tests have now become a part of many diagnostic and treatment guidelines. Considering the various challenges for in-house viral testing related to the standardization, validation, and precision; they are gradually being replaced by the United States Food and Drug Administration (US FDA) cleared tests. This review summarizes the various viral quantification methods and also discusses the clinical applicability of these in human immunodeficiency virus, Hepatitis B virus, Hepatitis C virus, Cytomegalovirus, and Epstein Barr virus infected patients. Further the challenges and future perspectives of VL testing have also been discussed.

  3. Quantitative nucleic acid amplification methods and their implications in clinical virology (United States)

    Singh, Mini P; Galhotra, Shipra; Saigal, Karnika; Kumar, Archit; Ratho, Radha Kanta


    Recently, a number of techniques have been approved for quantification of viral nucleic acids in clinical samples. Viral load (VL) tests have considerable importance in the management of patients and are widely used in routine diagnosis. In clinical virology, VL testing are important to monitor the antiviral treatment, to initiate preemptive therapy, to understand pathogenesis, and to evaluate the infectivity. These tests have now become a part of many diagnostic and treatment guidelines. Considering the various challenges for in-house viral testing related to the standardization, validation, and precision; they are gradually being replaced by the United States Food and Drug Administration (US FDA) cleared tests. This review summarizes the various viral quantification methods and also discusses the clinical applicability of these in human immunodeficiency virus, Hepatitis B virus, Hepatitis C virus, Cytomegalovirus, and Epstein Barr virus infected patients. Further the challenges and future perspectives of VL testing have also been discussed.

  4. Gene expression profiling of RNA extracted from FFPE tissues: NuGEN technologies' whole-transcriptome amplification system. (United States)

    Turner, Leah; Heath, Joe Don; Kurn, Nurith


    Gene expression profiling of RNA isolated from formalin fixed, paraffin-embedded (FFPE) tissue samples has been historically challenging. Yet FFPE samples are sought-after because of the in-depth retrospective records typically associated with them rendering these samples a valuable resource for translational medicine studies. Extensive degradation, chemical modifications, and cross-linking have made it difficult to isolate RNA of sufficient quality required for large-scale gene expression profiling studies. NuGEN Technologies' WT-Ovation™ FFPE System linearly amplifies RNA from FFPE samples through a robust and simple whole-transcriptome approach using as little as 50 ng total RNA isolated from FFPE samples. The amplified material may be labeled with validated kits and/or protocols from NuGEN for analysis on any of the major gene expression microarray platforms, including: Affymetrix, Agilent, and Illumina gene expression arrays. Results compare well with those obtained using RNA from fresh-frozen samples. RNA quality from FFPE samples varies significantly and neither sample age nor sample size analysis via gel electrophoresis or the Agilent Bioanalyzer system accurately predict materials suitable for amplification. Therefore, NuGEN has validated a correlative qPCR-based analytical method for the RNA derived from FFPE samples which effectively predicts array results. The NuGEN approach enables fast and successful analysis of samples previously thought to be too degraded for gene expression analysis.

  5. Detection of influenza A and B with the Alere™ i Influenza A & B: a novel isothermal nucleic acid amplification assay (United States)

    Hazelton, Briony; Gray, Timothy; Ho, Jennifer; Ratnamohan, V Mala; Dwyer, Dominic E; Kok, Jen


    Background Rapid influenza diagnostic tests (RIDTs) have an important role in clinical decision-making; however, the performances of currently available assays vary widely. Objectives We evaluated the performance of the Alere™ i Influenza A&B (Alere™ iNAT), a rapid isothermal nucleic acid amplification assay that has recently received FDA clearance, for the detection of influenza A and B viruses during the Australian influenza season of 2013. Results were compared to two other RIDTs tested in parallel; Quidel Sofia® Influenza A+B fluorescent immunoassay (FIA) and Alere™ BinaxNOW® Influenza A & B immunochromatographic (ICT) assay. Methods A total of 202 paired nasopharyngeal swabs collected from patients ≥16 years old with an influenza-like illness (ILI) were eluted in 2 ml of universal transport medium (UTM) that was used to perform all three RIDTs in parallel. Reverse-transcription polymerase chain reaction (RT-PCR) was used as the reference standard. Results Compared to RT-PCR, Alere™ iNAT detected 77·8% influenza A positive samples versus 71·4% and 44·4% for the Quidel Sofia® Influenza A+B FIA and BinaxNOW® Influenza A & B ICT assay, respectively. For influenza B, Alere™ iNAT detected 75% of those positive by RT-PCR, versus 33·3% and 25·0% for Sofia® and BinaxNOW®, respectively. The specificity of Alere™ iNAT was 100% for influenza A and 99% for influenza B. Conclusions Alere™ i Influenza A&B is a promising new rapid influenza diagnostic assay with potential point-of-care applications. PMID:25728758

  6. [Studies on rapid detection of food-borne pathogenic bacteria by nucleic acid testing and related technology]. (United States)

    Cao, Wei; Wang, Mingzhong; Wang, Xiaoying; Liu, Xiumei


    The traditional methods of bacteria isolation, cultivation and identification are time-consuming, which can't meet the needs of the control and prevention of food-borne diseases. Recently, various kinds of rapid methods for food-borne pathogenic bacteria detection have emerged with the prompt development of nucleic acid testing technology. The application studies on polymerase chain reaction and the techniques derived from it, nucleic acid isothermal amplification, oligonucleotide microarray, immunomagnetic separation and DNA biosensing on food-borne pathogenic bacteria including Salmonella, Staphylococcus aureus and Enterohemorrhagic Escherchia coli, etc. were reviewed.

  7. Clinical performance of automated real-time nucleic acid amplification technology for rapid and simultaneous detection of tuberculosis and rifampicin resistance assay in diagnosis of pulmonary tuberculosis in 214 cases%利福平耐药结核分枝杆菌实时荧光定量核酸扩增检测技术在214例诊断肺结核患者中的临床应用评价

    Institute of Scientific and Technical Information of China (English)

    何贵清; 李涛; 施伎蝉; 宁洪叶; 吴祥兵; 蔡明明; 吴正兴; 胡陈婵; 蒋贤高


    目的:评估利福平耐药结核分枝杆菌实时荧光定量核酸扩增检测技术(Xpert M TB/RIF)在温州地区诊断肺结核及利福平耐药的临床应用价值。方法纳入可疑肺结核、临床诊断肺结核和可疑耐药肺结核患者214例,采集痰标本同时送检抗酸染色涂片、液体培养和 Xpert M TB/RIF 检测。以临床最终诊断结果为金标准,比较三种方法检测结核分枝杆菌的敏感度、特异度。以液体药物敏感试验结果为金标准,Xpert M TB/RIF 检测利福平耐药的敏感度和特异度。率的比较采取卡方检验。结果以临床最终诊断结果作为金标准,Xpert M TB/RIF 检测结核分枝杆菌的敏感度高于抗酸染色涂片(69.5%比44.1%,χ2=23.31,P <0.01),而与液体培养比较敏感度差异无统计学意义(69.5%比62.1%,χ2=2.15,P>0.05);Xpert M TB/RIF 在痰涂片阳性与阴性的标本中检测结核分枝杆菌的敏感度分别为97.4%和47.5%,在痰涂片阳性与阴性的标本中检测结核分枝杆菌的特异度均为100.0%。以液体药物敏感试验结果为金标准,Xpert M TB/RIF 检测痰标本利福平耐药的敏感度和特异度分别为92.9%和98.8%。结论 Xpert M TB/RIF 能够快速、准确地检测结核分枝杆菌及其利福平耐药性,且敏感度较高,具有很好的应用价值。%Objective To evaluate the clinical application of the automated nucleic acid amplification technology for rapid and simultaneous detection of tuberculosis and rifampicin resistance (Xpert M TB/RIF) in diagnosis of pulmonary tuberculosis in Wenzhou .Methods A total of 214 patients with suspected pulmonary tuberculosis , clinical diagnosed tuberculosis or suspected drug‐resistant tuberculosis were enrolled in this study .The patients′ sputum specimens were collected for acid‐fast smear ,liquid culture and Xpert M TB/RIF assay .The sensitivity

  8. Detection and identification of human Plasmodium species with real-time quantitative nucleic acid sequence-based amplification

    Directory of Open Access Journals (Sweden)

    Kager Piet A


    Full Text Available Abstract Background Decisions concerning malaria treatment depend on species identification causing disease. Microscopy is most frequently used, but at low parasitaemia (Plasmodium antigen detection do often not allow for species discrimination as microscopy does, but also become insensitive at Methods This paper reports the development of a sensitive and specific real-time Quantitative Nucleic Acid Sequence Based Amplification (real-time QT-NASBA assays, based on the small-subunit 18S rRNA gene, to identify the four human Plasmodium species. Results The lower detection limit of the assay is 100 – 1000 molecules in vitro RNA for all species, which corresponds to 0.01 – 0.1 parasite per diagnostic sample (i.e. 50 μl of processed blood. The real-time QT-NASBA was further evaluated using 79 clinical samples from malaria patients: i.e. 11 Plasmodium. falciparum, 37 Plasmodium vivax, seven Plasmodium malariae, four Plasmodium ovale and 20 mixed infections. The initial diagnosis of 69 out of the 79 samples was confirmed with the developed real-time QT-NASBA. Re-analysis of seven available original slides resolved five mismatches. Three of those were initially identified as P. malariae mono-infection, but after re-reading the slides P. falciparum was found, confirming the real-time QT-NASBA result. The other two slides were of poor quality not allowing true species identification. The remaining five discordant results could not be explained by microscopy, but may be due to extreme low numbers of parasites present in the samples. In addition, 12 Plasmodium berghei isolates from mice and 20 blood samples from healthy donors did not show any reaction in the assay. Conclusion Real-time QT-NASBA is a very sensitive and specific technique with a detection limit of 0.1 Plasmodium parasite per diagnostic sample (50 μl of blood and can be used for the detection, identification and quantitative measurement of low parasitaemia of Plasmodium species, thus


    Directory of Open Access Journals (Sweden)

    K. Leshukov


    Full Text Available The technology of butter with the "OmegaTrin" complex with the balanced content of polynonsaturated fat acids is developed. Studied the fatty acid composition of milk - raw materials, optimal amount of insertion of polyunsaturated fatty acids, organoleptic characteristics of enriched butter; studied physico-chemical properties and biological value (biological effectiveness of the final product, fatty acid composition of a new product, set the shelf life and developed an oil recipe.

  10. Sensitive electrochemical detection of telomerase activity using spherical nucleic acids gold nanoparticles triggered mimic-hybridization chain reaction enzyme-free dual signal amplification. (United States)

    Wang, Wen-Jing; Li, Jing-Jing; Rui, Kai; Gai, Pan-Pan; Zhang, Jian-Rong; Zhu, Jun-Jie


    We report an electrochemical sensor for telomerase activity detection based on spherical nucleic acids gold nanoparticles (SNAs AuNPs) triggered mimic-hybridization chain reaction (mimic-HCR) enzyme-free dual signal amplification. In the detection strategy, SNAs AuNPs and two hairpin probes were employed. SNAs AuNPs as the primary amplification element, not only hybridized with the telomeric repeats on the electrode to amplify signal but also initiated the subsequent secondary amplification, mimic-hybridization chain reaction of two hairpin probes. If the cells' extracts were positive for telomerase activity, SNAs AuNPs could be captured on the electrode. The carried initiators could trigger an alternative hybridization reaction of two hairpin probes that yielded nicked double helices. The signal was further amplified enzyme-free by numerous hexaammineruthenium(III) chloride ([Ru(NH3)6](3+), RuHex) inserting into double-helix DNA long chain by electrostatic interaction, each of which could generate an electrochemical signal at appropriate potential. With this method, a detection limit of down to 2 HeLa cells and a dynamic range of 10-10,000 cells were achieved. Telomerase activities of different cell lines were also successfully evaluated.

  11. Label-free and sensitive fluorescence detection of nucleic acid, based on combination of a graphene oxid /SYBR green I dye platform and polymerase assisted signal amplification (United States)

    Zhu, Xiao; Xing, Da


    A new label-free isothermal fluorescence amplification detection for nucleic acid has been developed. In this paper, we first developed a novel sensitive and specific detection platform with an unmodified hairpin probe (HP) combination of the graphene oxid (GO)/ SYBR green I dye (SG), which was relied on the selective principle of adsorption and the high quenching efficiency of GO. Then for the application of this new strategy, we used Mirco RNA-21 (Mir-21) as the target to evaluate this working principle of our design. When the target was hybridizing with the HP and inducing its conformation of change, an efficient isothermal circular strand-displacement polymerization reaction was activating to assist the first signal amplification. In this format, the formed complex conformation of DNA would interact with its high affinity dye, then detached from the surface of GO after incubating with the platform of GO/intercalating dye. This reaction would accompany with obvious fluorescence recovery, and accomplish farther signal enhancement by a mass of intercalating dye inserting into the minor groove of the long duplex replication product. By taking advantage of the multiple amplification of signal, this method exerted substantial enhancement in sensitivity and could be used for rapid and selective detection of Mir-21 with attomole range. It is expected that this cost-effective GO based sensor might hold considerable potential to apply in bioanalysis studies.

  12. Detection of Campylobacter jejuni and Campylobacter coli in chicken meat samples by real-time nucleic acid sequence-based amplification with molecular beacons. (United States)

    Churruca, E; Girbau, C; Martínez, I; Mateo, E; Alonso, R; Fernández-Astorga, A


    A nucleic acid sequence-based amplification (NASBA) assay based on molecular beacons was used for real-time detection of Campylobacter jejuni and Campylobacter coli in samples of chicken meat. A set of specific primers and beacon probe were designed to target the 16S rRNA of both species. The real-time NASBA protocol including the RNA isolation was valid for both of the cell suspensions in buffered saline and the artificially contaminated chicken meat samples. The presence of rRNA could be correlated with cellular viability, following inactivation of the bacteria by heating, in inoculated chicken meat samples but not in RNase-free cell suspensions.

  13. Lead-acid battery technologies fundamentals, materials, and applications

    CERN Document Server

    Jung, Joey; Zhang, Jiujun


    Lead-Acid Battery Technologies: Fundamentals, Materials, and Applications offers a systematic and state-of-the-art overview of the materials, system design, and related issues for the development of lead-acid rechargeable battery technologies. Featuring contributions from leading scientists and engineers in industry and academia, this book:Describes the underlying science involved in the operation of lead-acid batteriesHighlights advances in materials science and engineering for materials fabricationDelivers a detailed discussion of the mathematical modeling of lead-acid batteriesAnalyzes the

  14. Point of care nucleic acid detection of viable pathogenic bacteria with isothermal RNA amplification based paper biosensor (United States)

    Liu, Hongxing; Xing, Da; Zhou, Xiaoming


    Food-borne pathogens such as Listeria monocytogenes have been recognized as a major cause of human infections worldwide, leading to substantial health problems. Food-borne pathogen identification needs to be simpler, cheaper and more reliable than the current traditional methods. Here, we have constructed a low-cost paper biosensor for the detection of viable pathogenic bacteria with the naked eye. In this study, an effective isothermal amplification method was used to amplify the hlyA mRNA gene, a specific RNA marker in Listeria monocytogenes. The amplification products were applied to the paper biosensor to perform a visual test, in which endpoint detection was performed using sandwich hybridization assays. When the RNA products migrated along the paper biosensor by capillary action, the gold nanoparticles accumulated at the designated Test line and Control line. Under optimized experimental conditions, as little as 0.5 pg/μL genomic RNA from Listeria monocytogenes could be detected. The whole assay process, including RNA extraction, amplification, and visualization, can be completed within several hours. The developed method is suitable for point-of-care applications to detect food-borne pathogens, as it can effectively overcome the false-positive results caused by amplifying nonviable Listeria monocytogenes.

  15. A simple, inexpensive device for nucleic acid amplification without electricity-toward instrument-free molecular diagnostics in low-resource settings.

    Directory of Open Access Journals (Sweden)

    Paul LaBarre

    Full Text Available BACKGROUND: Molecular assays targeted to nucleic acid (NA markers are becoming increasingly important to medical diagnostics. However, these are typically confined to wealthy, developed countries; or, to the national reference laboratories of developing-world countries. There are many infectious diseases that are endemic in low-resource settings (LRS where the lack of simple, instrument-free, NA diagnostic tests is a critical barrier to timely treatment. One of the primary barriers to the practicality and availability of NA assays in LRS has been the complexity and power requirements of polymerase chain reaction (PCR instrumentation (another is sample preparation. METHODOLOGY/PRINCIPAL FINDINGS: In this article, we investigate the hypothesis that an electricity-free heater based on exothermic chemical reactions and engineered phase change materials can successfully incubate isothermal NA amplification assays. We assess the heater's equivalence to commercially available PCR instruments through the characterization of the temperature profiles produced, and a minimal method comparison. Versions of the prototype for several different isothermal techniques are presented. CONCLUSIONS/SIGNIFICANCE: We demonstrate that an electricity-free heater based on exothermic chemical reactions and engineered phase change materials can successfully incubate isothermal NA amplification assays, and that the results of those assays are not significantly different from ones incubated in parallel in commercially available PCR instruments. These results clearly suggest the potential of the non-instrumented nucleic acid amplification (NINA heater for molecular diagnostics in LRS. When combined with other innovations in development that eliminate power requirements for sample preparation, cold reagent storage, and readout, the NINA heater will comprise part of a kit that should enable electricity-free NA testing for many important analytes.

  16. Technological Aspects of Chemoenzymatic Epoxidation of Fatty Acids, Fatty Acid Esters and Vegetable Oils: A Review

    Directory of Open Access Journals (Sweden)

    Eugeniusz Milchert


    Full Text Available The general subject of the review is analysis of the effect of technological parameters on the chemoenzymatic epoxidation processes of vegetable oils, fatty acids and alkyl esters of fatty acids. The technological parameters considered include temperature, concentration, amount of hydrogen peroxide relative to the number of unsaturated bonds, the amounts of enzyme catalysts, presence of solvent and amount of free fatty acids. Also chemical reactions accompanying the technological processes are discussed together with different technological options and significance of the products obtained.

  17. Microfluidic Digital Chip for Absolute Quantification of Nucleic Acid Amplification%一种可绝对定量核酸的数字PCR微流控芯片

    Institute of Scientific and Technical Information of China (English)

    朱强远; 杨文秀; 高一博; 于丙文; 邱琳; 周超; 金伟; 金钦汉; 牟颖


    quantitatively using 18sRNA cDNA from A549. The sample was serially diluted and target DNA molecules were randomly distributed in chip, which can be described by Poisson distribution. If a panel contains template DNA much less than on average 0. 5 template molecules per chamber, then there would be 0 or 1 copy in a chamber; the chambers containing template DNA are amplified by PCR and analyzed to be positive, while the chambers without template molecule are analyzed to be negative, the copy number of target DNA molecules of the sample can be read out accurately just by counting positive reactions. The result has proved the feasibility and flexibility of the microfluidic chip that single molecule amplification and absolute quantification of nucleic acid amplification can be succeeded. The design of the chip has the potential to meet the requirements for the general labs: inexpensive, sensitive, economizing labor time and reagent, and simple operation. It is possible to make the digital PCR technology into ordinary laboratory, and make it become one of the common tools in biology research, especially in the developing world. This technique is useful for molecular genetic analysis in cancer and infectious diseases, single cell analysis, bacterial determination, non-invasive prenatal diagnosis in which many biologists are interested.


    Directory of Open Access Journals (Sweden)



    Full Text Available Citric acid, C3H4OH(COOH3, (Scheele and Wehmer 1897 can be generally manufactured by chemical synthesis which is not much preferred now-a-days because of high costs involved in it and also by fermentation of sugar containing sources in the presence of fungus Aspergillus niger. Citric acid is used in confections and soft drinks ( as a flavouring agent, in metal-cleaning compositions, and in improving the stability of foods and other organic substances by suppressing the deleterious action of dissolved metal salts. Fermentation results in the breakdown of complex organic substances into simpler ones through the action of catalysis. This project involves the production of citric acid from fungal strain of Aspergillus niger ATCC 9142, using various sources like cane molasses, beet molasses, sweet potato and grape sugar by employing submerged and surface fermentation. The fermentation process has been carried out at ph 4.5 and temperature 28 0C. The recovery of citric acid from fermented broth is generally performed through three procedures-precipitation, extraction and adsorption(mainly using ion-exchange resins. The main aim of the project is to achieve a cost reduction in citric acid production by using less expensive substrates.

  19. Nucleic acid amplification tests for diagnosis of smear-negative TB in a high HIV-prevalence setting: a prospective cohort study.

    Directory of Open Access Journals (Sweden)

    J Lucian Davis

    Full Text Available Nucleic acid amplification tests are sensitive for identifying Mycobacterium tuberculosis in populations with positive sputum smears for acid-fast bacilli, but less sensitive in sputum-smear-negative populations. Few studies have evaluated the clinical impact of these tests in low-income countries with high burdens of TB and HIV.We prospectively enrolled 211 consecutive adults with cough ≥2 weeks and negative sputum smears at Mulago Hospital in Kampala, Uganda. We tested a single early-morning sputum specimen for Mycobacterium tuberculosis DNA using two nucleic acid amplification tests: a novel in-house polymerase chain reaction targeting the mycobacterial secA1 gene, and the commercial Amplified® Mycobacterium tuberculosis Direct (MTD test (Gen-Probe Inc, San Diego, CA. We calculated the diagnostic accuracy of these index tests in reference to a primary microbiologic gold standard (positive mycobacterial culture of sputum or bronchoalveolar lavage fluid, and measured their likely clinical impact on additional tuberculosis cases detected among those not prescribed initial TB treatment.Of 211 patients enrolled, 170 (81% were HIV-seropositive, with median CD4+ T-cell count 78 cells/µL (interquartile range 29-203. Among HIV-seropositive patients, 94 (55% reported taking co-trimoxazole prophylaxis and 29 (17% reported taking antiretroviral therapy. Seventy-five patients (36% had culture-confirmed TB. Sensitivity of MTD was 39% (95% CI 28-51 and that of secA1 was 24% (95% CI 15-35. Both tests had specificities of 95% (95% CI 90-98. The MTD test correctly identified 18 (24% TB patients not treated at discharge and led to a 72% relative increase in the smear-negative case detection rate.The secA1 and MTD nucleic acid amplification tests had moderate sensitivity and high specificity for TB in a predominantly HIV-seropositive population with negative sputum smears. Although newer, more sensitive nucleic acid assays may enhance detection of

  20. Biomaterials in light amplification (United States)

    Mysliwiec, Jaroslaw; Cyprych, Konrad; Sznitko, Lech; Miniewicz, Andrzej


    Biologically produced or inspired materials can serve as optical gain media, i.e. they can exhibit the phenomenon of light amplification. Some of these materials, under suitable dye-doping and optical pumping conditions, show lasing phenomena. The emerging branch of research focused on obtaining lasing action in highly disordered and highly light scattering materials, i.e. research on random lasing, is perfectly suited for biological materials. The use of biomaterials in light amplification has been extensively reported in the literature. In this review we attempt to report on progress in the development of biologically derived systems able to show the phenomena of light amplification and random lasing together with the contribution of our group to this field. The rich world of biopolymers modified with molecular aggregates and nanocrystals, and self-organized at the nanoscale, offers a multitude of possibilities for tailoring luminescent and light scattering properties that are not easily replicated in conventional organic or inorganic materials. Of particular importance and interest are light amplification and lasing, or random lasing studies in biological cells and tissues. In this review we will describe nucleic acids and their complexes employed as gain media due to their favorable optical properties and ease of manipulation. We will report on research conducted on various biomaterials showing structural analogy to nucleic acids such as fluorescent proteins, gelatins in which the first distributed feedback laser was realized, and also amyloids or silks, which, due to their dye-doped fiber-like structure, allow for light amplification. Other materials that were investigated in that respect include polysaccharides, like starch exhibiting favorable photostability in comparison to other biomaterials, and chitosan, which forms photonic crystals or cellulose. Light amplification and random lasing was not only observed in processed biomaterials but also in living

  1. Detection of Vibrio cholerae by isothermal cross-priming amplification combined with nucleic acid detection strip analysis. (United States)

    Zhang, Xia; Du, Xin-Jun; Guan, Chun; Li, Ping; Zheng, Wen-Jie; Wang, Shuo


    Vibrio cholerae is a water- and food-borne human pathogen, and V. cholerae serotypes O1 and O139 have attracted attention because of their severe pathogenesis. However, non-O1, non-O139 cholera vibrios (NCVs) were also recently recognized as having virulence properties. In this study, we developed a cross-priming amplification (CPA) method for the detection of all serotypes of V. cholerae. The specificity of the CPA method was tested using a panel of 60 different bacterial strains. All of the V. cholerae strains showed positive results, and 41 other types of bacteria gave negative results. The limit of detection of the CPA method was 79.28 fg of genomic DNA, 4.2 × 10(2) CFU/ml for bacteria in pure culture, and 5.6 CFU per 25 g of sample with pre-enrichment. This method showed a higher sensitivity than the loop-mediated isothermal amplification (LAMP) method did and was more convenient to perform. These results indicate that the CPA method can be used for the rapid preliminary screening of V. cholerae.

  2. Sensitivity and Specificity of Nucleic Acid Sequence-Based Amplification Method (NASBA for Diagnosis of Cutaneous Leishmaniasis

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    Niazi, A


    Full Text Available Background and Objective: Employing advanced diagnostics for molecular identification of the Lishmania parasite is has a more sensitivity and specificity in comparison to the microscopic methods. RT- PCR is also introduced as one of the best known techniques for diagnosis of this parasite; however, the method is not widely used due to its expensive equipments and the time requested.the application of NASBA method is shown high efficient for diagnosis of live parasite. The aim of this study is comparison sensivity and specificity between NASBA isothermal amplification and RT-PCR for molecular detection of lishmania major. Material and Methods: 28 skin biopsy from Oscar of patients was prepared and total RNA was extracted. Then, the using of specific primers designed for 18srRNA region, this region was amplified using NASBA isothemal amplification. The RNA amplicons were produced in less than 90 minutes and then identified via electrophoresed agaros gel after staining with Syber Gold flourecent probes for the purpose increasing sensitivity and specificity Result: In this study, NASBA and RT-PCR method are sensitivity 81%, specificity of 51% and 100% respectively for detection of Leishmania parasites inscars Conclusion: NASBA isothermal method can be applied with high sensitivity and specificity for the identification of cutaneous leishmaniasis, this method can be fed with live microorganisms and response to treatment in patients examined. Keywords: Cutaneous Leishmanisis, NASBA, 18S rRNA

  3. A microfluidic platform for transcription- and amplification-free detection of zepto-mole amounts of nucleic acid molecules. (United States)

    Mayr, Reinhard; Haider, Michaela; Thünauer, Roland; Haselgrübler, Thomas; Schütz, Gerhard J; Sonnleitner, Alois; Hesse, Jan


    Here we report the development of a device for the transcription- and amplification-free detection of DNA and RNA molecules down to the zepto-mole range. A microfluidic chip with a built-in microarray was used for manipulation of nano-liter sample volumes. Specific staining and immobilization of the target molecules was achieved via a double hybridization approach thereby avoiding bias due to enzymatic processes like reverse transcription and PCR amplification. Therefore, target molecules were indirectly labeled by pre-hybridization to complementary Cy5-labeled probes. The remaining single-stranded portion of each target molecule could subsequently hybridize to complementary capture probes of a microarray. Thus a target-mediated immobilization of labeled DNA took place. By means of an ultra-sensitive fluorescence readout, all molecules hybridized to the microarray could be detected. The combination of minimized sample volume and single molecule detection yielded a detection limit of 39 fM (831 molecules in 35.4 nl assay volume) for target DNA and 16 fM (338 molecules) for target RNA after 1h on-chip hybridization.

  4. Visual detection and differentiation of Classic Swine Fever Virus strains using nucleic acid sequence-based amplification (NASBA) and G-quadruplex DNAzyme assay (United States)

    Lu, Xiaolu; Shi, Xueyao; Wu, Gege; Wu, Tiantian; Qin, Rui; Wang, Yi


    The split G-quadruplex DNAzyme has emerged as a valuable tool for visual DNA detection. Here, we successfully integrated colorimetric split G-quadruplex DNAzyme assay with nucleic acid sequence-based amplification to generate a novel detection approach, allowing visual and rapid detection for the RNA of Shimen and HCLV strains of Classic Swine Fever Virus (CSFV). CSFV is a RNA virus that causes a highly contagious disease in domestic pigs and wild boar. With this method, we were able to detect as little as 10 copies/ml of CSF viral RNA within 3 h in serum samples taken from the field. No interference was encountered in the amplification and detection of Classic Swine Fever Virus in the presence of non-target RNA or DNA. Moreover, Shimen and HCLV strains of Classic Swine Fever Virus could be easily differentiated using the NASBA-DNAzyme system. These findings indicate the NASBA-DNAzyme system is a rapid and practical technique for detecting and discriminating CSFV strains and may be applied to the detection of other RNA viruses. PMID:28287135


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    Ricardo Luiz Dantas MACHADO


    Full Text Available We report an adaptation of a technique for the blood sample collection (GFM as well as for the extraction and amplification of Plasmodium DNA for the diagnosis of malaria infection by the PCR/ELISA. The method of blood sample collection requires less expertise and saves both time and money, thus reducing the cost by more than half. The material is also suitable for genetic analysis in either fresh or stored specimens prepared by this method.Relatamos a adaptação de uma técnica para coleta de amostras (MFV e outra para extração, amplificação de DNA de parasitas da malária para diagnóstico por PCR/ELISA. O método de coleta de amostras requer menos habilidade e economisa tempo e dinheiro, assim reduzindo a mais da metade o custo. O material é também adequado para análise genética em especimens frescos ou estocados, preparados por este método.

  6. Technology and economic assessment of lactic acid production and uses

    Energy Technology Data Exchange (ETDEWEB)

    Datta, R.; Tsai, S.P.


    Lactic acid has been an intermediate-volume specialty chemical (world production {approximately}50,000 tons/yr) used in a wide range of food-processing and industrial applications. Potentially, it can become a very large-volume, commodity-chemical intermediate produced from carbohydrates for feedstocks of biodegradable polymers, oxygenated chemicals, environmentally friendly ``green`` solvents, and other intermediates. In the past, efficient and economical technologies for the recovery and purification of lactic acid from fermentation broths and its conversion to the chemical or polymer intermediates had been the key technology impediments and main process cost centers. Development and deployment of novel separations technologies, such as electrodialysis with bipolar membranes, extractive and catalytic distillations, and chemical conversion, can enable low-cost production with continuous processes in large-scale operations. The emerging technologies can use environmentally sound lactic acid processes to produce environmentally useful products, with attractive process economics. These technology advances and recent product and process commercialization strategies are reviewed and assessed.

  7. Identification and complete genome sequencing of paramyxoviruses in mallard ducks (Anas platyrhynchos using random access amplification and next generation sequencing technologies

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    van den Berg Thierry


    Full Text Available Abstract Background During a wildlife screening program for avian influenza A viruses (AIV and avian paramyxoviruses (APMV in Belgium, we isolated two hemagglutinating agents from pools of cloacal swabs of wild mallards (Anas platyrhynchos caught in a single sampling site at two different times. AIV and APMV1 were excluded using hemagglutination inhibition (HI testing and specific real-time RT-PCR tests. Methods To refine the virological identification of APMV2-10 realized by HI subtyping tests and in lack of validated molecular tests for APMV2-10, random access amplification was used in combination with next generation sequencing for the sequence independent identification of the viruses and the determination of their genomes. Results Three different APMVs were identified. From one pooled sample, the complete genome sequence (15054 nucleotides of an APMV4 was assembled from the random sequences. From the second pooled sample, the nearly complete genome sequence of an APMV6 (genome size of 16236 nucleotides was determined, as well as a partial sequence for an APMV4. This APMV4 was closely related but not identical to the APMV4 isolated from the first sample. Although a cross-reactivity with other APMV subtypes did not allow formal identification, the HI subtyping revealed APMV4 and APMV6 in the respective pooled samples but failed to identify the co-infecting APMV4 in the APMV6 infected pool. Conclusions These data further contribute to the knowledge about the genetic diversity within the serotypes APMV4 and 6, and confirm the limited sensitivity of the HI subtyping test. Moreover, this study demonstrates the value of a random access nucleic acid amplification method in combination with massive parallel sequencing. Using only a moderate and economical sequencing effort, the characterization and full genome sequencing of APMVs can be obtained, including the identification of viruses in mixed infections.

  8. Full scale phosphoric acid fuel cell stack technology development (United States)

    Christner, L.; Faroque, M.


    The technology development for phosphoric acid fuel cells is summarized. The preparation, heat treatment, and characterization of carbon composites used as bipolar separator plates are described. Characterization included resistivity, porosity, and electrochemical corrosion. High density glassy carbon/graphite composites performed well in long-term fuel cell endurance tests. Platinum alloy cathode catalysts and low-loaded platinum electrodes were evaluated in 25 sq cm cells. Although the alloys displayed an initial improvement, some of this improvement diminished after a few thousand hours of testing. Low platinum loading (0.12 mg/sq cm anodes and 0.3 mg/sq cm cathodes) performed nearly as well as twice this loading. A selectively wetproofed anode backing paper was tested in a 5 by 15 inch three-cell stack. This material may provide for acid volume expansion, acid storage, and acid lateral distribution.

  9. Technology development for phosphoric acid fuel cell powerplant (phase 2) (United States)

    Christner, L.


    The status of technology for the manufacturing and testing of 1200 sq. cm cell materials, components, and stacks for on-site integrated energy systems is assessed. Topics covered include: (1) preparation of thin layers of silicon carbide; (2) definition and control schemes for volume changes in phosphoric acid fuel cells; (3) preparation of low resin content graphite phenolic resin composites; (4) chemical corrosion of graphite-phenolic resin composites in hot phosphoric acid; (5) analysis of electrical resistance of composite materials for fuel cells; and (6) fuel cell performance and testing.

  10. Enzymatic electrochemical detection of epidemic-causing Vibrio cholerae with a disposable oligonucleotide-modified screen-printed bisensor coupled to a dry-reagent-based nucleic acid amplification assay. (United States)

    Yu, Choo Yee; Ang, Geik Yong; Chan, Kok Gan; Banga Singh, Kirnpal Kaur; Chan, Yean Yean


    In this study, we developed a nucleic acid-sensing platform in which a simple, dry-reagent-based nucleic acid amplification assay is combined with a portable multiplex electrochemical genosensor. Preparation of an amplification reaction mix targeting multiple DNA regions of interest is greatly simplified because the lyophilized reagents need only be reconstituted with ultrapure water before the DNA sample is added. The presence of single or multiple target DNAs causes the corresponding single-stranded DNA (ssDNA) amplicons to be generated and tagged with a fluorescein label. The fluorescein-labeled ssDNA amplicons are then analyzed using capture probe-modified screen-printed gold electrode bisensors. Enzymatic amplification of the hybridization event is achieved through the catalytic production of electroactive α-naphthol by anti-fluorescein-conjugated alkaline phosphatase. The applicability of this platform as a diagnostic tool is demonstrated with the detection of toxigenic Vibrio cholerae serogroups O1 and O139, which are associated with cholera epidemics and pandemics. The platform showed excellent diagnostic sensitivity and specificity (100%) when challenged with 168 spiked stool samples. The limit of detection was low (10 colony-forming units/ml) for both toxigenic V. cholerae serogroups. A heat stability assay revealed that the dry-reagent amplification reaction mix was stable at temperatures of 4-56 °C, with an estimated shelf life of seven months. The findings of this study highlight the potential of combining a dry-reagent-based nucleic acid amplification assay with an electrochemical genosensor in a more convenient, sensitive, and sequence-specific detection strategy for multiple target nucleic acids.

  11. Technological and economic potential of poly(lactic acid) and lactic acid derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Datta, R.; Tsai, S.P.; Bonsignore, P.; Moon, S.H.; Frank, J.R.


    Lactic acid has been an intermediate-volume specialty chemical (world production {approximately}40,000 tons/yr) used in a wide range of food processing and industrial applications. lactic acid h,as the potential of becoming a very large volume, commodity-chemical intermediate produced from renewable carbohydrates for use as feedstocks for biodegradable polymers, oxygenated chemicals, plant growth regulators, environmentally friendly ``green`` solvents, and specially chemical intermediates. In the past, efficient and economical technologies for the recovery and purification of lactic acid from crude fermentation broths and the conversion of tactic acid to the chemical or polymer intermediates had been the key technology impediments and main process cost centers. The development and deployment of novel separations technologies, such as electrodialysis (ED) with bipolar membranes, extractive distillations integrated with fermentation, and chemical conversion, can enable low-cost production with continuous processes in large-scale operations. The use of bipolar ED can virtually eliminate the salt or gypsum waste produced in the current lactic acid processes. In this paper, the recent technical advances in tactic and polylactic acid processes are discussed. The economic potential and manufacturing cost estimates of several products and process options are presented. The technical accomplishments at Argonne National Laboratory (ANL) and the future directions of this program at ANL are discussed.

  12. An assessment of acid rock drainage continuous monitoring technology (United States)

    Fytas, K.; Hadjigeorgiou, J.


    In order to assess the magnitude and impact at affected mine sites of acid rock drainage (ARD), fixed-frequency sampling is often employed. This often involves manual sampling, at regular time intervals, of water and solids. It is felt that such sampling does not adequately describe the system evolution. Continuous monitoring offers a viable alternative in that it can better follow the seasonal fluctuations and high-frequency variations that characterize ARD. This paper evaluates existing continuous monitoring technology.

  13. Selective Adsorption and Chiral Amplification of Amino Acids in Vermiculite Clay -Implications for the origin of biochirality

    CERN Document Server

    Fraser, Donald G; Jakschitz, Thomas; Rode, Bernd M


    Smectite clays are hydrated layer silicates that, like micas, occur naturally in abundance. Importantly, they have readily modifiable interlayer spaces that provide excellent sites for nanochemistry. Vermiculite is one such smectite clay and in the presence of small chain-length alkyl-NH3Cl ions, forms sensitive, 1-D ordered model clay systems with expandable nano-pore inter-layer regions. These inter-layers readily adsorb organic molecules. N-propyl NH3Cl vermiculite clay gels were used to determine the adsorption of alanine, lysine and histidine by chiral HPLC. The results show that during reaction with fresh vermiculite interlayers, significant chiral enrichment of either L- and D-enantiomers occurs depending on the amino acid. Chiral enrichment of the supernatant solutions is up to about 1% per pass. In contrast, addition to clay interlayers already reacted with amino acid solutions resulted in little or no change in D/L ratio during the time of the experiment. Adsorption of small amounts of amphiphilic o...

  14. Towards a “Sample-In, Answer-Out” Point-of-Care Platform for Nucleic Acid Extraction and Amplification: Using an HPV E6/E7 mRNA Model System

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    Anja Gulliksen


    Full Text Available The paper presents the development of a “proof-of-principle” hands-free and self-contained diagnostic platform for detection of human papillomavirus (HPV E6/E7 mRNA in clinical specimens. The automated platform performs chip-based sample preconcentration, nucleic acid extraction, amplification, and real-time fluorescent detection with minimal user interfacing. It consists of two modular prototypes, one for sample preparation and one for amplification and detection; however, a common interface is available to facilitate later integration into one single module. Nucleic acid extracts (n=28 from cervical cytology specimens extracted on the sample preparation chip were tested using the PreTect HPV-Proofer and achieved an overall detection rate for HPV across all dilutions of 50%–85.7%. A subset of 6 clinical samples extracted on the sample preparation chip module was chosen for complete validation on the NASBA chip module. For 4 of the samples, a 100% amplification for HPV 16 or 33 was obtained at the 1 : 10 dilution for microfluidic channels that filled correctly. The modules of a “sample-in, answer-out” diagnostic platform have been demonstrated from clinical sample input through sample preparation, amplification and final detection.

  15. Evaluation of three enzyme immunoassays and a nucleic acid amplification test for the diagnosis of Clostridium difficile-associated diarrhea at a university hospital in Brazil

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    Rodrigo Otávio Silveira Silva


    Full Text Available Introduction Despite the known importance of Clostridium difficile as a nosocomial pathogen, few studies regarding Clostridium difficile infection (CDI in Brazil have been conducted. To date, the diagnostic tests that are available on the Brazilian market for the diagnosis of CDI have not been evaluated. The aim of this study was to compare the performances of four commercial methods for the diagnosis of CDI in patients from a university hospital in Brazil. Methods Three enzyme immunoassays (EIAs and one nucleic acid amplification test (NAAT were evaluated against a cytotoxicity assay (CTA and toxigenic culture (TC. Stool samples from 92 patients with suspected CDI were used in this study. Results Twenty-five (27.2% of 92 samples were positive according to the CTA, and 23 (25% were positive according to the TC. All EIAs and the NAAT test demonstrated sensitivities between 59 and 68% and specificities greater than 91%. Conclusions All four methods exhibited low sensitivities for the diagnosis of CDI, which could lead to a large number of false-negative results, an increased risk of cross-infection to other patients, and overtreatment with empirical antibiotics.

  16. Development of Reverse Transcription Loop-Mediated Isothermal Amplification for Simple and Rapid Detection of Promyelocytic Leukemia–Retinoic Acid Receptor α mRNA (United States)

    Hashimoto, Yuki; Hatayama, Yuki; Kojima, Nao; Morishita, Shota; Matsumoto, Satoko; Hosoda, Yuzuru; Hara, Ayako; Motokura, Toru


    Background Acute promyelocytic leukemia (APL) is a disease characterized by expression of Promyelocytic Leukemia–Retinoic Acid Receptor α (PML-RARα) chimeric mRNA. Although APL is curable, early death due to hemorrhage is a major problem. Here, we report the development of a simple and rapid diagnostic method for APL based on reverse transcription loop-mediated isothermal amplification (RT-LAMP). Methods An RT-LAMP primer set was designed to detect three types of PML-RARα mRNA in a single reaction. Serial dilutions of plasmid DNA containing bcr1, bcr2, or bcr3 PML-RARα sequences and RNA extracted from bone marrow aspirates of 6 patients with APL were used to compare the results of RT-LAMP and nested PCR assays. Results Plasmid DNA was amplified by RT-LAMP, for which the reaction time was > 4 h shorter and the lower detection limit was higher than for nested RT-PCR. Six of 7 samples tested positive by both methods. Conclusion We developed an RT-LAMP assay for simple and rapid PML-RARα mRNA detection that may be clinically useful for point-of-care testing and APL diagnosis. PMID:28070163

  17. Selective adsorption and chiral amplification of amino acids in vermiculite clay-implications for the origin of biochirality. (United States)

    Fraser, Donald G; Fitz, Daniel; Jakschitz, T; Rode, Bernd M


    Smectite clays are hydrated layer silicates that, like micas, occur naturally in abundance. Importantly, they have readily modifiable interlayer spaces that provide excellent sites for nanochemistry. Vermiculite is one such smectite clay and in the presence of small chain-length alkyl-NH(3)Cl ions forms sensitive, 1-D ordered model clay systems with expandable nano-pore inter-layer regions. These inter-layers readily adsorb organic molecules. n-Propyl NH(3)Cl vermiculite clay gels were used to determine the adsorption of alanine, lysine and histidine by chiral HPLC. The results show that during reaction with fresh vermiculite interlayers, significant chiral enrichment of either L- and D-enantiomers occurs depending on the amino acid. Chiral enrichment of the supernatant solutions is up to about 1% per pass. In contrast, addition to clay interlayers already reacted with amino acid solutions resulted in little or no change in D/L ratio during the time of the experiment. Adsorption of small amounts of amphiphilic organic molecules in clay inter-layers is known to produce Layer-by-Layer or Langmuir-Blodgett films. Moreover atomistic simulations show that self-organization of organic species in clay interlayers is important. These non-centrosymmetric, chirally active nanofilms may cause clays to act subsequently as chiral amplifiers, concentrating organic material from dilute solution and having different adsorption energetics for D- and L-enantiomers. The additional role of clays in RNA oligomerization already postulated by Ferris and others, together with the need for the organization of amphiphilic molecules and lipids noted by Szostak and others, suggests that such chiral separation by clays in lagoonal environments at normal biological temperatures might also have played a significant role in the origin of biochirality.

  18. Quantitation of viral load using real-time amplification techniques

    NARCIS (Netherlands)

    Niesters, H G


    Real-time PCR amplification techniques are currently used to determine the viral load in clinical samples for an increasing number of targets. Real-time PCR reduces the time necessary to generate results after amplification. In-house developed PCR and nucleic acid sequence-based amplification (NASBA

  19. Amplification of electrolyte uptake in the absorptive glass mat (AGM) separator for valve regulated lead acid (VRLA) batteries (United States)

    Kumar, Vijay; Kameswara Rao, P. V.; Rawal, Amit


    Absorptive glass mat (AGM) separators are widely used for valve regulated lead acid (VRLA) batteries due to their remarkable fiber and structural characteristics. Discharge performance and recharge effectiveness of VRLA batteries essentially rely on the distribution and saturation levels of the electrolyte within the AGM separator. Herein, we report an analytical model for predicting the wicking characteristics of AGM battery separators under unconfined and confined states. The model of wicking behavior of AGM is based upon Fries and Dreyer's approach that included the effect of gravity component which was neglected in classic Lucas-Washburn's model. In addition, the predictive model of wicking accounted for realistic structural characteristics of AGM via orientation averaging approach. For wicking under confined state, the structural parameters have been updated under defined level of compressive stresses based upon the constitutive equation derived for a planar network of fibers in AGM under transverse loading conditions. A comparison has been made between the theoretical models and experimental results of wicking behavior under unconfined and confined states. Most importantly, the presented work has highlighted the questionable validity of classic Lucas-Washburn model for predicting the wicking characteristics of AGM separator over longer time duration.

  20. 环介导恒温扩增(LAMP)技术及其在寄生虫检测中的应用%Loop-mediated isothermal amplification (LAMP) technology and its application in parasites detection

    Institute of Scientific and Technical Information of China (English)

    莫秀玲; 张鸿满; 黄维义


    近年来开发出一种新的恒温核酸扩增方法,即环介导恒温扩增(loop-mediated isithermal amplification,LAMP)法.LAMP技术具有简便、快速、高效、特异性强等优点,尤其适用于人类和动物疾病的检测.该文简要介绍了LAMP技术的原理,并对其在检测寄生虫如锥虫、疟原虫、巴贝虫、隐孢子虫和水生动物孢子虫等方面的应用进行综述.%In recent years,a new isothermal nucleic acid amplification method,100p-mediated isothermal amplification (LAMP)method has been developed and applied.LAMP is a simple,rapid,highlv efficient,highly specific gene amplification method,particularly suitable for human and animal disease detection.This paper briefly summarized the principal of LAMP and its applications in parasites detection,such as Trypanosoma,Plusmodium,Babesia,Cryptosporidium and Tetracapsuloides bryosalmonae in aquatic animals.

  1. Evaluation of a viral microarray based on simultaneous extraction and amplification of viral nucleotide acid for detecting human herpesviruses and enteroviruses.

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    Yi Liu

    Full Text Available In this study, a viral microarray based assay was developed to detect the human herpesviruses and enteroviruses associated with central nervous system infections, including herpes simplex virus type 1, type 2 (HSV1 and HSV2, Epstein-Barr virus (EBV, cytomegalovirus (CMV, enterovirus 71 (EV71, coxsackievirus A 16 (CA16 and B 5(CB5. The DNA polymerase gene of human herpesviruses and 5'-untranslated region of enteroviruses were selected as the targets to design primers and probes. Human herpesviruses DNA and enteroviruses RNA were extracted simultaneously by using a guanidinium thiocyanate acid buffer, and were subsequently amplified through a biotinylated asymmetry multiplex RT-PCR with the specific primer of enteroviruses. In total, 90 blood samples and 49 cerebrospinal fluids samples with suspected systemic or neurological virus infections were investigated. Out of 139 samples, 66 were identified as positive. The specificities of this multiplex RT-PCR microarray assay were over 96% but the sensitivities were various from 100% for HSV1, HSV2, EV71 and CB5, 95.83% for CMV, 80% for EBV to 71.43% for CA16 in comparison with reference standards of TaqMan qPCR/qRT-PCR. The high Kappa values (>0.90 from HSV1, HSV2, CMV, EV71 and CB5 were obtained, indicating almost perfect agreement in term of the 5 viruses detection. But lower Kappa values for EBV (0.63 and CA16 (0.74 displayed a moderate to substantial agreement. This study provides an innovation of simultaneous extraction, amplification, hybridization and detection of DNA viruses and RNA viruses with simplicity and specificity, and demonstrates a potential clinical utility for a variety of viruses' detection.

  2. Concordance study between one-step nucleic acid amplification and morphologic techniques to detect lymph node metastasis in papillary carcinoma of the thyroid. (United States)

    del Carmen, Sofía; Gatius, Sonia; Franch-Arcas, Guzmán; Baena, José Antonio; Gonzalez, Oscar; Zafon, Carlos; Cuevas, Dolors; Valls, Joan; Pérez, Angustias; Martinez, Mercedes; Ros, Susana; Macías, Carmen García; Iglesias, Carmela; Matías-Guiu, Xavier; de Álava, Enrique


    Tumor resection in papillary thyroid carcinoma (PTC) is often accompanied by lymph node (LN) removal of the central and lateral cervical compartments. One-step nucleic acid amplification (OSNA) is a polymerase chain reaction-based technique that quantifies cytokeratin 19 (CK19) messenger RNA copies. Our aim is to assess the value of OSNA in detection of LN metastases in PTC, in comparison with imprints and microscopic analysis of formalin-fixed, paraffin-embedded (FFPE) tissue. A total of 387 LNs from 37 patients were studied. From each half LN, 2 imprints were taken and analyzed with hematoxylin and eosin (H&E) and CK19 immunostaining. One half of the LN was submitted to OSNA and one half to FFPE processing and H&E and CK19 staining. For concordance analysis, every single LN was considered as a case. A group of 11 cases with discordant results between OSNA and H&E/CK19 FFPE sections were subjected to additional FFPE serial sectioning and H&E and CK19 staining. We found a high degree of concordance between the assays used, with sensitivities ranging from 0.81 to 0.95, and specificities ranging from 0.87 and 0.98. OSNA allowed upstaging of patients from pN0 to pN1, in comparison with standard pathologic analysis. Identification of a metastatic LN with more than 15000 CK19 messenger RNA copies predicted the presence of a second LN with macrometastasis (<5000 copies). In summary, the study shows that OSNA application in sentinel or suspicious LN may be helpful in assessing nodal status in PTC patients.

  3. Can mailed swab samples be dry-shipped for the detection of Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis by nucleic acid amplification tests? (United States)

    Gaydos, Charlotte A.; Farshy, Carol; Barnes, Mathilda; Quinn, Nicole; Agreda, Patricia; Rivers, Charles A.; Schwebke, Jane; Papp, John


    Background Dry-shipped and mailed vaginal swabs collected at home have been used in research studies for the detection of C. trachomatis (CT), N. gonorrhoeae (GC), and Trichomonas vaginalis (TV) by nucleic acid amplification tests (NAATs) in screening programs. A verification study was performed to compare the limit of detection of CT, GC, and TV on swabs that were dry-shipped to paired swabs that were wet-shipped in transport media through the U.S. mail. Methods The Centers for Disease Control and Prevention prepared inocula in sterile water to mock simulated urogenital swabs with high to low concentrations of CT and GC. Replicate swabs were inoculated with 100µl of dilutions, were dry transported or placed into commercial transport media (“wet”) for mailing for NAAT testing. The University of Alabama prepared replicate concentrations of TV, which were similarly shipped and tested by NAAT. Results All paired dry and wet swabs were detectable for CT. For GC, all paired dry and wet swabs were detectable for GC at concentrations ≥103. At 102 and 10 CFU/ml, the 10 replicate GC results were variably positive. For TV, wet and dry shipped concentrations > 102 TV/ml tested positive, while results at 10 TV/ml were negative for dry swabs. Holding replicate dry swabs at 55°C 5 days before testing did not affect results. Conclusion NAATs were able to detect CT, GC, and TV on dry transported swabs. Using NAATs for testing home-collected, urogenital swabs mailed in a dry state to a laboratory may be useful for outreach screening programs. PMID:22578934

  4. Clinical utility of a nested nucleic acid amplification format in comparison to viral culture for the diagnosis of mucosal herpes simplex infection in a genitourinary medicine setting

    Directory of Open Access Journals (Sweden)

    Wyatt Dorothy E


    Full Text Available Abstract Background Nested nucleic acid amplification tests are often thought too sensitive or prone to generatingfalse positive results for routine use. The current study investigated the specificity and clinicalutility of a routine multiplex nested assay for mucosal herpetic infections. Methods Ninety patients, categorised into those clinically diagnosed to (a have and (b not haveherpetic infection, were enrolled. Swabs from oral and ano-genital sites were assayed by thenested assay and culture and the results assessed against clinical evaluation for diagnosingherpetic infections; cell content was also recorded. Results Twenty-six and 64 patients were thought to (a have and (b not have mucosal herpeticinfection. Taking the clinical evaluation as indicating the presence of herpetic infection, thenested polymerase chain reaction and culture had respective sensitivities of 19/26 (73% and12/26 (46% (Χ2 p = 0.02. There was no significant difference in specificities between nPCR62/64 (97% and culture 63/64 (98% (Χ2 p = 1.0. Cell content was important for viraldetection by nPCR (Χ2 p = 0.07 but not culture. Nesting was found necessary for sensitivity anddid not reduce specificity. Assay under-performance appeared related to sub-optimal cellcontent (20% but may have reflected clinical over-diagnosis. The results suggest the need forvalidating specimen cell quality. Conclusions This study questions the value of routine laboratory confirmation of mucosal herpetic infection. The adoption of a more discriminatory usage of laboratory diagnostic facilities for genital herpetic infection, taking account of cell content, and restricting it to those cases where it actually affects patient management, may be warranted.

  5. A touchdown nucleic acid amplification protocol as an alternative to culture backup for immunofluorescence in the routine diagnosis of acute viral respiratory tract infections

    Directory of Open Access Journals (Sweden)

    Feeney Susan A


    Full Text Available Abstract Background Immunofluorescence and virus culture are the main methods used to diagnose acute respiratory virus infections. Diagnosing these infections using nucleic acid amplification presents technical challenges, one of which is facilitating the different optimal annealing temperatures needed for each virus. To overcome this problem we developed a diagnostic molecular strip which combined a generic nested touchdown protocol with in-house primer master-mixes that could recognise 12 common respiratory viruses. Results Over an 18 month period a total of 222 specimens were tested by both immunofluorescence and the molecular strip. The specimens came from 103 males (median age 3.5 y, 80 females (median age 9 y and 5 quality assurance scheme specimens. Viruses were recovered from a number of specimen types including broncho-alveolar lavage, nasopharyngeal secretions, sputa, post-mortem lung tissue and combined throat and nasal swabs. Viral detection by IF was poor in sputa and respiratory swabs. A total of 99 viruses were detected in the study from 79 patients and 4 quality control specimens: 31 by immunofluorescence and 99 using the molecular strip. The strip consistently out-performed immunofluorescence with no loss of diagnostic specificity. Conclusions The touchdown protocol with pre-dispensed primer master-mixes was suitable for replacing virus culture for the diagnosis of respiratory viruses which were negative by immunofluorescence. Results by immunofluorescence were available after an average of 4–12 hours while molecular strip results were available within 24 hours, considerably faster than viral culture. The combined strip and touchdown protocol proved to be a convenient and reliable method of testing for multiple viruses in a routine setting.

  6. Diagnosis of tuberculosis by using a nucleic acid amplification test in an urban population with high HIV prevalence in the United States.

    Directory of Open Access Journals (Sweden)

    Miwako Kobayashi

    Full Text Available BACKGROUND: Use of nucleic acid amplification tests (NAAT for the diagnosis of Mycobacterium tuberculosis (TB has been recommended on respiratory specimens submitted for acid-fast bacilli (AFB testing. It also helps distinguish between TB and non-tuberculous mycobacteria (NTM species in a setting where NTM rates are relatively high. The purposes of this study are to describe the trend and characteristics of all AFB smear-positive respiratory samples that underwent amplified Mycobacterium tuberculosis direct (MTD testing, a type of NAAT, and to evaluate the clinical utility and necessity of the test for diagnosis of TB in a population with high-HIV prevalence. METHODS: Prospective diagnostic testing and retrospective data analyses were conducted on all AFB smear-positive respiratory samples that underwent MTD testing from 2001 to 2011 at Grady Memorial Hospital (GMH, Atlanta, USA. The test performance was compared to culture. RESULTS: A total of 2,240 AFB smear-positive specimens from 1,412 patients were tested and analyzed in the study. The proportion of specimens that were culture-positive for TB was 28.5%. Sensitivity, specificity, positive predictive value, and negative predictive value of the MTD were 99.0%, 98.0%, 95.3% and 99.6%, respectively. A downward trend was observed in the yearly numbers as well as the proportions of MTD-positive specimens during the study period (p<0.01. There were 2,027 (90.5% specimens from patients with known HIV status, of which 70.6% was HIV positive and the majority of them (81.8% had CD4 counts of less than 200 cells/µL. HIV-positives were more likely to have NTM compared to HIV negatives (67.7% vs. 35.4%, p<0.01. CONCLUSION: Despite the decrease in the incidence of TB, NAAT continues to be an accurate and important diagnostic test in a population with high HIV prevalence, and it differentiates TB and NTM organisms.

  7. Application of a molecular beacon based real-time isothermal amplification (MBRTIA) technology for simultaneous detection of Bacillus cereus and Staphylococcus aureus. (United States)

    Mandappa, I M; Joglekar, Prasanna; Manonmani, H K


    A multiplex real-time isothermal amplification assay was developed using molecular beacons for the detection of Bacillus cereus and Staphylococcus aureus by targeting four important virulence genes. A correlation between targeting highly accessible DNA sequences and isothermal amplification based molecular beacon efficiency and sensitivity was demonstrated using phi(Φ)29 DNA polymerase at a constant isothermal temperature of 30 °C. It was very selective and consistently detected down to 10(1) copies of DNA. The specificity and sensitivity of this assay, when tested with pure culture were high, surpassing those of currently used PCR assays for the detection of these organisms. The molecular beacon based real-time isothermal amplification (MBRTIA) assay could be carried out entirely in 96 well plates or well strips, enabling a rapid and high-throughput detection of food borne pathogens.

  8. Role of deoxyribonucleic acid technology in forensic dentistry

    Directory of Open Access Journals (Sweden)

    Pankaj Datta


    Full Text Available In the last few years, Deoxyribonucleic Acid (DNA analysis methods have been applied to forensic cases. Forensic dental record comparison has been used for human identification in cases where destruction of bodily tissues or prolonged exposure to the environment has made other means of identification impractical, that is, after fire exposure or mass disaster. Teeth play an important role in identification and criminology, due to their unique characteristics and relatively high degree of physical and chemical resistance. The use of a DNA profile test in forensic dentistry offers a new perspective in human identification. The DNA is responsible for storing all the genetic material and is unique to each individual. The currently available DNA tests have high reliability and are accepted as legal proofs in courts. This article gives an overview of the evolution of DNA technology in the last few years, highlighting its importance in cases of forensic investigation.

  9. Role of deoxyribonucleic acid technology in forensic dentistry. (United States)

    Datta, Pankaj; Datta, Sonia Sood


    In the last few years, Deoxyribonucleic Acid (DNA) analysis methods have been applied to forensic cases. Forensic dental record comparison has been used for human identification in cases where destruction of bodily tissues or prolonged exposure to the environment has made other means of identification impractical, that is, after fire exposure or mass disaster. Teeth play an important role in identification and criminology, due to their unique characteristics and relatively high degree of physical and chemical resistance. The use of a DNA profile test in forensic dentistry offers a new perspective in human identification. The DNA is responsible for storing all the genetic material and is unique to each individual. The currently available DNA tests have high reliability and are accepted as legal proofs in courts. This article gives an overview of the evolution of DNA technology in the last few years, highlighting its importance in cases of forensic investigation.

  10. Electricity-free amplification and detection for molecular point-of-care diagnosis of HIV-1. (United States)

    Singleton, Jered; Osborn, Jennifer L; Lillis, Lorraine; Hawkins, Kenneth; Guelig, Dylan; Price, Will; Johns, Rachel; Ebels, Kelly; Boyle, David; Weigl, Bernhard; LaBarre, Paul


    In resource-limited settings, the lack of decentralized molecular diagnostic testing and sparse access to centralized medical facilities can present a critical barrier to timely diagnosis, treatment, and subsequent control and elimination of infectious diseases. Isothermal nucleic acid amplification methods, including reverse transcription loop-mediated isothermal amplification (RT-LAMP), are well-suited for decentralized point-of-care molecular testing in minimal infrastructure laboratories since they significantly reduce the complexity of equipment and power requirements. Despite reduced complexity, however, there is still a need for a constant heat source to enable isothermal nucleic acid amplification. This requirement poses significant challenges for laboratories in developing countries where electricity is often unreliable or unavailable. To address this need, we previously developed a low-cost, electricity-free heater using an exothermic reaction thermally coupled with a phase change material. This heater achieved acceptable performance, but exhibited considerable variability. Furthermore, as an enabling technology, the heater was an incomplete diagnostic solution. Here we describe a more precise, affordable, and robust heater design with thermal standard deviation electricity-free heater and NALF-detection platform, we demonstrate sensitive and repeatable detection of HIV-1 with a ß-actin positive internal amplification control from processed sample to result in less than 80 minutes. Together, these elements are building blocks for an electricity-free platform capable of isothermal amplification and detection of a variety of pathogens.

  11. A novel thermostable polymerase for RNA and DNA Loop-mediated isothermal amplification (LAMP

    Directory of Open Access Journals (Sweden)

    Yogesh eChander


    Full Text Available Meeting the goal of providing point of care (POC tests for molecular detection of pathogens in low resource settings places stringent demands on all aspects of the technology. OmniAmp DNA polymerase (Pol is a thermostable viral enzyme that enables true POC use in clinics or in field by overcoming important barriers to isothermal amplification. In this paper, we describe the multiple advantages of OmniAmp Pol as an isothermal amplification enzyme and provide examples of its use in loop-mediated isothermal amplification (LAMP for pathogen detection. The inherent reverse transcriptase activity of OmniAmp Pol allows single enzyme detection of RNA targets in RT-LAMP. Common methods of nucleic acid amplification are highly susceptible to sample contaminants, necessitating elaborate nucleic acid purification protocols that are incompatible with POC or field use. OmniAmp Pol was found to be less inhibited by whole blood components typical in certain crude sample preparations . Moreover, the thermostability of the enzyme compared to alternative DNA polymerases (Bst and reverse transcriptases allows pretreatment of complete reaction mixes immediately prior to amplification, which facilitates amplification of highly structured genome regions. Compared to Bst, OmniAmp Pol has a faster time to result, particularly with more dilute templates. Molecular diagnostics in field settings can be challenging due to the lack of refrigeration. The stability of OmniAmp Pol is compatible with a dry format that enables long term storage at ambient temperatures. A final requirement for field operability is compatibility with either commonly available instruments or, in other cases, a simple, inexpensive, portable detection mode requiring minimal training or power. Detection of amplification products is shown using lateral flow strips and analysis on a real-time PCR instrument. Results of this study show that OmniAmp Pol is ideally suited for low resource molecular

  12. Evaluation of a field-portable DNA microarray platform and nucleic acid amplification strategies for the detection of arboviruses, arthropods, and bloodmeals. (United States)

    Grubaugh, Nathan D; Petz, Lawrence N; Melanson, Vanessa R; McMenamy, Scott S; Turell, Michael J; Long, Lewis S; Pisarcik, Sarah E; Kengluecha, Ampornpan; Jaichapor, Boonsong; O'Guinn, Monica L; Lee, John S


    Highly multiplexed assays, such as microarrays, can benefit arbovirus surveillance by allowing researchers to screen for hundreds of targets at once. We evaluated amplification strategies and the practicality of a portable DNA microarray platform to analyze virus-infected mosquitoes. The prototype microarray design used here targeted the non-structural protein 5, ribosomal RNA, and cytochrome b genes for the detection of flaviviruses, mosquitoes, and bloodmeals, respectively. We identified 13 of 14 flaviviruses from virus inoculated mosquitoes and cultured cells. Additionally, we differentiated between four mosquito genera and eight whole blood samples. The microarray platform was field evaluated in Thailand and successfully identified flaviviruses (Culex flavivirus, dengue-3, and Japanese encephalitis viruses), differentiated between mosquito genera (Aedes, Armigeres, Culex, and Mansonia), and detected mammalian bloodmeals (human and dog). We showed that the microarray platform and amplification strategies described here can be used to discern specific information on a wide variety of viruses and their vectors.

  13. Process technology for the application of d-amino acid oxidases in pharmaceutical intermediate manufacturing

    DEFF Research Database (Denmark)

    Tindal, Stuart; Carr, Reuben; Archer, Ian V. J.


    Recent advances in biocatalysis have seen increased interest in the use of D-amino acid oxidase to synthesize optically pure amino acids. However, the creation of a genuine oxidase based platform technology will require suitable process technology as well as an understanding of the challenges and...

  14. The Seneca Amplification Construction

    Directory of Open Access Journals (Sweden)

    Wallace Chafe


    Full Text Available The polysynthetic morphology of the Northern Iroquoian languages presents a challenge to studies of clause combining. The discussion here focuses on a Seneca construction that may appear within a single clause but may also straddle clause boundaries. It amplifies the information provided by a referent, here called the trigger, that is introduced by the pronominal prefix within a verb or occasionally in some other way. The particle neh signals that further information about that referent will follow. This construction is found at four levels of syntactic complexity. At the first level the trigger and its amplification occur within the same prosodic phrase and the amplification is a noun. At the second level the amplification occurs in a separate prosodic phrase but remains a noun. At the third level the amplification exhibits verb morphology but has been lexicalized with a nominal function. At the fourth level the amplification functions as a full clause and neh serves as a marker of clause combining. Several varieties of amplification are discussed, as are cases in which the speaker judges that no amplification is needed. It is suggested that the typologically similar Caddo language illustrates a situation in which this construction could never arise, simply because Caddo verbs lack the pronominal element that triggers the construction in Seneca.

  15. Post-Fragmentation Whole Genome Amplification-Based Method (United States)

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


    This innovation is derived from a proprietary amplification scheme that is based upon random fragmentation of the genome into a series of short, overlapping templates. The resulting shorter DNA strands (genomic hybridization microarray, SNP analysis, and sequencing. The standard reaction can be performed with minimal hands-on time, and can produce amplified DNA in as little as three hours. Post-fragmentation whole genome amplification-based technology provides a robust and accurate method of amplifying femtogram levels of starting material into microgram yields with no detectable allele bias. The amplified DNA also facilitates the preservation of samples (spacecraft samples) by amplifying scarce amounts of template DNA into microgram concentrations in just a few hours. Based on further optimization of this technology, this could be a feasible technology to use in sample preservation for potential future sample return missions. The research and technology development described here can be pivotal in dealing with backward/forward biological contamination from planetary missions. Such efforts rely heavily on an increasing understanding of the burden and diversity of microorganisms present on spacecraft surfaces throughout assembly and testing. The development and implementation of these technologies could significantly improve the comprehensiveness and resolving power of spacecraft-associated microbial population censuses, and are important to the continued evolution and advancement of planetary protection capabilities. Current molecular procedures for assaying spacecraft-associated microbial burden and diversity have inherent sample loss issues at practically every step, particularly nucleic acid extraction. In engineering a molecular means of amplifying nucleic acids directly from single cells in their native state within the sample matrix, this innovation has circumvented entirely the need for DNA extraction regimes in the sample processing scheme.

  16. Loop-mediated isothermal amplification as an emerging technology for detection of Yersinia ruckeri the causative agent of enteric red mouth disease in fish

    Directory of Open Access Journals (Sweden)

    Soliman Hatem


    Full Text Available Abstract Background Enteric Redmouth (ERM disease also known as Yersiniosis is a contagious disease affecting salmonids, mainly rainbow trout. The causative agent is the gram-negative bacterium Yersinia ruckeri. The disease can be diagnosed by isolation and identification of the causative agent, or detection of the Pathogen using fluorescent antibody tests, ELISA and PCR assays. These diagnostic methods are laborious, time consuming and need well trained personnel. Results A loop-mediated isothermal amplification (LAMP assay was developed and evaluated for detection of Y. ruckeri the etiological agent of enteric red mouth (ERM disease in salmonids. The assay was optimised to amplify the yruI/yruR gene, which encodes Y. ruckeri quorum sensing system, in the presence of a specific primer set and Bst DNA polymerase at an isothermal temperature of 63°C for one hour. Amplification products were detected by visual inspection, agarose gel electrophoresis and by real-time monitoring of turbidity resulted by formation of LAMP amplicons. Digestion with HphI restriction enzyme demonstrated that the amplified product was unique. The specificity of the assay was verified by the absence of amplification products when tested against related bacteria. The assay had 10-fold higher sensitivity compared with conventional PCR and successfully detected Y. ruckeri not only in pure bacterial culture but also in tissue homogenates of infected fish. Conclusion The ERM-LAMP assay represents a practical alternative to the microbiological approach for rapid, sensitive and specific detection of Y. ruckeri in fish farms. The assay is carried out in one hour and needs only a heating block or water bath as laboratory furniture. The advantages of the ERM-LAMP assay make it a promising tool for molecular detection of enteric red mouth disease in fish farms.

  17. Amplification of NOON States

    CERN Document Server

    Agarwal, G S; Rai, Amit


    We examine the behavior of a Non Gaussian state like NOON state under phase insensitive amplification. We derive analytical result for the density matrix of the NOON state for arbitrary gain of the amplifier. We consider cases of both symmetric and antisymmetric amplification of the two modes of the NOON state. We quantitatively evaluate the loss of entanglement by the amplifier in terms of the logarithmic negativity parameter. We find that NOON states are more robust than their Gaussian counterparts.

  18. Amplification of NOON States



    We examine the behavior of a Non Gaussian state like NOON state under phase insensitive amplification. We derive analytical result for the density matrix of the NOON state for arbitrary gain of the amplifier. We consider cases of both symmetric and antisymmetric amplification of the two modes of the NOON state. We quantitatively evaluate the loss of entanglement by the amplifier in terms of the logarithmic negativity parameter. We find that NOON states are more robust than their Gaussian coun...

  19. 表面等离子共振技术结合滚环扩增法检测丙型肝炎病毒%Surface plasmon resonance technology combined with rolling circle amplification for detection of hepatitis C virus

    Institute of Scientific and Technical Information of China (English)

    季明辉; 刘春晓; 赵纯中; 徐云庆; 徐华; 欧青叶; 孙秋香; 滕娟; 胡贵方; 郑义; 顾大勇; 龙军; 鲁卫平; 何建安; 谈书勤; 史蕾


    Objective To develop rolling circle amplification (RCA) method combined with specific surface plasmon resonance ( SPR) nucleic acid gold-chip for the deteclion of hepatitis C virus ( HCV). Methods According to the specific test sequence of HCV x-tail region, probes and primers for detecting HCV with RCA method were designed and synthesized, and were divided into test group, negative sample group and positive sample group for RCA experiments to detect HCV. The template concentration was diluted into ten gradients, and the detection limit of SPR combined with RCA method was evaluated. Based on the ordinary gold chip, through the surface chemical processing, the nucleic acid chip with high specificity was obtained, and the anti-protein capacity of protein chip was verified by anti-protein experiment. Real-time detection of RCA reaction and signal magnification reaction was conducted with double channel SPR apparatus. Sixty-three blood samples collected from clinics were delected by SPR combined with RCA method, comparisons were made with Real-Time PCR, and the sensitivity and specificity were evaluated. Results The minimum detection concentration of SPR combined with RCA method in HCV testing was 1 pmol/L, which was lower than the detection limit of Real-Time PCR (0. 1 nmol/L). SPR chip had the favorable anti-protein absorptive capacity. The signal-to-noise ratio of double channel SPR apparatus in detection of RCA chip system was 100, which achieved the detection of HCV. The sensitivity of SPR combined with RCA method in detection of clinical samples was 90.0% (27/30), and the specificity was 84. 8% (28/33) (x2 = 8-10, P = 0. 004). Conclusion SPR combined with RCA method combines biological sensing technology with in situ amplification technology, which may detect HCV in a fast, label-free and real-time way.%目的 研究滚环扩增(RCA)技术结合特异性表面等离子共振(SPR)金膜芯片检测丙型肝炎病毒(HCv)的方法.方法 根据丙型肝炎x-tail

  20. 多重连接探针扩增(MLPA)技术同时检测五种病毒的研究%Simultaneous Detection of Five Virues by Multiplex Ligation-dependent Probe Amplification(MLPA) Technology

    Institute of Scientific and Technical Information of China (English)

    史喜菊; 马贵平; 乔彩霞; 郭志红; 张伟; 刘全国; 李炎鑫; 李冰玲


    Current detection technologies for diagnosis of animal diseases is mostly targeted at single pathogen,but the prevalence of animal diseases is characterized by mixed infection with more than one pathogen.In order to resolve the trouble,here we describe the new multiparameter assay,which is based on multiplex ligation-dependent probe amplification(MLPA) technology with the advantages of specificity,sensitivity and high-throughput.Five pairs of specific probe targeted at Swine influenza virus(SIV),Pseudorabies virus(PRV),Foot and mouth disease virus (FMDV),Transmissible gastroenteritis virus (TGEV) and Porcine reproductive and respiratory syndrome virus (PRRSV),were designed,respectiviely.The mixture of five standard RNA/DNA was used as template,together with the mixture of these probes as probe and the PCR universal primer,one MLPA method for simultaneous detection of the five porcine viruses was developed.The result of specificity test showed that the designed probes had good specificity without mismatch between each virus-specific probe pair and other six viruses,and that the mixture of the five pairs of probe only amplified the corresponding one specific fragment from the eight virus templates,respectively,no amplification signal was produced among Porcine parvovirus(PPV),Classical swine fever virus(CSFV) and Porcine epidemic diarrhea virus(PEDV) with the same probe mixture.The result of sensitivity test showed that the concentration of nucleic acid of single virus in one MLPA reaction was up to 3 000~6 000 copies.All the results showed that the developed MLPA method in this article accomplished the simultaneous detection of five viruses in one reaction,which indicates MLPA technology may be an alternative to simultaneous detection of many pathogens in the future in the field of veterinary medicine.%现有的动物疫病诊断技术多是针对单一病原进行的,而动物疫病的流行却出现了多种病毒混合感染,现有诊断技术不能很好地

  1. Plasminogen-based capture combined with amplification technology for the detection of PrP(TSE in the pre-clinical phase of infection.

    Directory of Open Access Journals (Sweden)

    Christiane Segarra

    Full Text Available BACKGROUND: Variant Creutzfeldt-Jakob disease (vCJD is a neurodegenerative infectious disorder, characterized by a prominent accumulation of pathological isoforms of the prion protein (PrP(TSE in the brain and lymphoid tissues. Since the publication in the United Kingdom of four apparent vCJD cases following transfusion of red blood cells and one apparent case following treatment with factor VIII, the presence of vCJD infectivity in the blood seems highly probable. For effective blood testing of vCJD individuals in the preclinical or clinical phase of infection, it is considered necessary that assays detect PrP(TSE concentrations in the femtomolar range. METHODOLOGY/PRINCIPAL FINDINGS: We have developed a three-step assay that firstly captures PrP(TSE from infected blood using a plasminogen-coated magnetic-nanobead method prior to its serial amplification via protein misfolding cyclic amplification (PMCA and specific PrP(TSE detection by western blot. We achieved a PrP(TSE capture yield of 95% from scrapie-infected material. We demonstrated the possibility of detecting PrP(TSE in white blood cells, in buffy coat and in plasma isolated from the blood of scrapie-infected sheep collected at the pre-clinical stage of the disease. The test also allowed the detection of PrP(TSE in human plasma spiked with a 10(-8 dilution of vCJD-infected brain homogenate corresponding to the level of sensitivity (femtogram required for the detection of the PrP(TSE in asymptomatic carriers. The 100% specificity of the test was revealed using a blinded panel comprising 96 human plasma samples. CONCLUSION/SIGNIFICANCE: We have developed a sensitive and specific amplification assay allowing the detection of PrP(TSE in the plasma and buffy coat fractions of blood collected at the pre-clinical phase of the disease. This assay represents a good candidate as a confirmatory assay for the presence of PrP(TSE in blood of patients displaying positivity in large scale screening

  2. A New Homogenizing Technology to Obtain Rosmarinic Acid from Perilla Oil Meal

    Institute of Scientific and Technical Information of China (English)

    TANG Wei-zhuo; LIU Yan-ze; ZHAO Yu-qing


    Objective To optimize the extraction technology of the active component,rosmarinic acid,an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid,in perilla oil meal for the first time by a new homogenizing technology called smashing tissue extraction (STE).Methods Orthogonal design was used to optimize the extraction condition.The content of rosmarinic acid was quantified from the methanol crude extract with the help of HPLC.Results The optimization of STE process to get rosmarinic acid from the perilla oil meal was the ratio of liquid to solid material at 10∶1 and the power of extraction at 150 V,extracting twice (2 min for each time).Conclusion STE could be applied to extracting the active ingredients from the oil meals due to its high extraction efficiency.This new homogenizing technology has advantages on saving extraction time,raising extraction efficiency,and maintaining the temperature sensitive constituents.

  3. Gene amplification in carcinogenesis

    Directory of Open Access Journals (Sweden)

    Lucimari Bizari


    Full Text Available Gene amplification increases the number of genes in a genome and can give rise to karyotype abnormalities called double minutes (DM and homogeneously staining regions (HSR, both of which have been widely observed in human tumors but are also known to play a major role during embryonic development due to the fact that they are responsible for the programmed increase of gene expression. The etiology of gene amplification during carcinogenesis is not yet completely understood but can be considered a result of genetic instability. Gene amplification leads to an increase in protein expression and provides a selective advantage during cell growth. Oncogenes such as CCND1, c-MET, c-MYC, ERBB2, EGFR and MDM2 are amplified in human tumors and can be associated with increased expression of their respective proteins or not. In general, gene amplification is associated with more aggressive tumors, metastases, resistance to chemotherapy and a decrease in the period during which the patient stays free of the disease. This review discusses the major role of gene amplification in the progression of carcinomas, formation of genetic markers and as possible therapeutic targets for the development of drugs for the treatment of some types of tumors.

  4. Establishment of the Nucleic Acid Sequence-based Amplification Method for Detecting Vibio Alginolyticus%溶藻弧菌的依赖于核酸序列恒温扩增检测方法的建立

    Institute of Scientific and Technical Information of China (English)

    秦胜利; 王建广


    A new method, based on Nucleic Acid Sequence-based Amplification (NAS-BA) to detect Vibio alginolyticus of samples, was established. A highly specific set of primers was synthesized to target the hsp60 gene of Vibio alginolyticus so as to establish Nucleic Acid Sequence-based Amplification method. Specificity and sensitivity were tested. The results showed that the sensitivity of NASBA was 6. 9×102cfu ? mL-1 which was higher than the result of PCR method. Detecting Vibio alginolyticus with NASBA was more specific and sensitive than PCR method and has lower instrumental requirement. So,there is a broad prospect.%采用自行建立和优化的依赖于核酸序列恒温扩增(NASBA)检测体系,对溶藻弧菌进行检测.采用溶藻弧菌的hsp60基因为目的片段设计特异性引物,建成可快速检测溶藻弧菌的NASBA检测法,并进行了特异性和灵敏度试验.结果表明:所建立起的NASBA检测方法,灵敏度为6.9× 102 cfu·mL-1,高于普通PCR方法.溶藻弧菌的依赖于核酸序列恒温扩增检测方法具有较高灵敏度和和良好特异性,并且对仪器要求更低,用普通恒温设备即可进行反应,具有广阔的推广前景.

  5. Development of Acetic Acid Removal Technology for the UREX+Process

    Energy Technology Data Exchange (ETDEWEB)

    Robert M. Counce; Jack S. Watson


    It is imperative that acetic acid is removed from a waste stream in the UREX+process so that nitric acid can be recycled and possible interference with downstreatm steps can be avoidec. Acetic acid arises from acetohydrozamic acid (AHA), and is used to suppress plutonium in the first step of the UREX+process. Later, it is hydrolyzed into hydroxyl amine nitrate and acetic acid. Many common separation technologies were examined, and solvent extraction was determined to be the best choice under process conditions. Solvents already used in the UREX+ process were then tested to determine if they would be sufficient for the removal of acetic acid. The tributyl phosphage (TBP)-dodecane diluent, used in both UREX and NPEX, was determined to be a solvent system that gave sufficient distribution coefficients for acetic acid in addition to a high separation factor from nitric acid.

  6. A modified PCR protocol for consistent amplification of fatty acid desaturase (FAD) alleles in marker-assisted backcross breeding for high oleic trait in peanut (United States)

    High oleic acid, such as is found in olive oil, is desirable for the healthy cholesterol-lowering benefits. The oxidative stability of the oil with high oleic acid also gives longer “shelve life” for peanut products. These benefits drive the breeding effort toward developing high oleic peanuts worl...

  7. Identification and evaluation of a new nucleic acid amplification test target for specific detection of Mycobacterium tuberculosis complex%鉴别结核分枝杆菌复合群的新型核酸扩增检测靶标评价

    Institute of Scientific and Technical Information of China (English)

    高诗会; 赵英伟; 胡忠义; 王洁; 陆俊梅; 闫丽萍; 郭琪; 马慧; 秦莲花


    Objective To identify and evaluate a new nucleic acid amplification (NAA) test target for specific detection of Mycobacterium tuberculosis (MTB) complex (MTC).Methods MTC-specific fragment was obtained by ISSR genotyping technology.Primer pairs were designed based on the sequences of MTC-specific fragment and tested in 211 mycobacterial strains including 107 MTC strains and 104 nontuberculous mycobacteria (NTM) strains.IS6110 element (specific identification of MTC strains) and 16s rRNA gene (specific identification of Mycobacterium) amplification were used as a control to evaluate the efficacy of the NAA test target in the detection of MTC strains.Results One MTC-specific fragment with the length of 588 bp,located in 315947-316534 of the genome from MTB reference strain H37 Rv,were obtained,cloned and sequenced.MTC-specific primer pairs MTCF/R were designed based on these sequences.All 211 mycobacterial strains accurately produced the genus-specific 16s rRNA amplicon.All MTC strains were positive in the MTCF/R PCR amplification while 99% MTC strains (106/107) were positive in the amplification of IS6110 sequences.All NTM strains were negative in both IS6110 and MTCF/R PCR amplification.Conclusions The MTC-specific fragment developed in this study can be used as a new NAA test target to correctly distinguish MTC from NTM.%目的 寻找新的鉴别诊断MTB复合群(MTC)高特异度和敏感的核酸靶标.方法 利用简单序列重复区间(ISSR)分型技术平台筛选MTC的特征片段,克隆测序获得特征序列并进行序列同源性分析,以该序列为基础设计MTC特征引物,并对211株分枝杆菌菌株(其中MTC107株、非结核分枝杆菌104株)进行鉴别检测.利用分枝杆菌属特征序列16s rRNA和MTC特征序列IS6110的鉴别结果,对MTC特征引物检测结果进行评估.结果 通过ISSR分型获得588 bp的MTC特征片段,该序列为MTC菌株的特征序列,位于MTB标准株H37Rv基因组的315947 ~316534位,以该序

  8. Fieldwork Report for the Nucleic Acid Technology Lab

    DEFF Research Database (Denmark)

    Ramos, Juan David Hincapie

    The development of new technologies requires an understanding of the social issues technologies would confront when deployed. Such is the case of e-Science solutions like the Mini-Grid, whose future users are molecular biologists. The successful adoption of the Mini-Grid requires its design...... to account to the existing conditions of the molecular biologists. In this technical report we present the results of an initial fieldwork study of molecular biologists. We present their organization structure, their roles, their tools, their activities, and information management behaviors and collaboration...

  9. Complementarity of ELISA and nucleic acid amplification test in blood screening%血筛用酶联免疫吸附试验与核酸检测互补性探讨和研究

    Institute of Scientific and Technical Information of China (English)

    曾劲峰; 叶贤林; 马兰; 张红; 庄乃保; 李活


    目的 为了提高临床输血的安全性,探讨核酸检测(NAT)与酶联免疫吸附试验(ELISA)技术在血液筛查工作中的互补特性.方法 对2007年6月至2008年3月采集的无偿献血者标本共计45 022例用ELISA血清学检测方法对血液传染性指标HBsAg、抗-HCV、抗-HIV、梅毒螺旋体、丙氨酸氨基转移酶(ALT)进行检测,各项指标均正常的标本用NAT技术检测,以研究2种检测方法的互补性.结果 45 022例标本中血清学检测及ALT不合格人数共计803例,不合格率为1.98%.对各项检测指标合格的36 806例标本进行核酸检测,结果HBV-DNA呈阳性3例.HBV-RNA、HIV-RNA均未检出.结论 NAT与ELISA的血液筛查检测互补作用主要体现在3个方面:1)病理生理过程互补,检测窗口期的长短主要由检测对象的生理属性来决定,而非检测方法缺陷.2)检测方法学互补,由于检测方法学的不同使得NAT技术的检测灵敏度明显高于ELISA血清学检测方法.3)影响各自实验的错误发生各不相同.%Objective To investigate the complementarity of ELISA and nucleic acid amplification test(NAT)in blood screening,and to improve the security of clinieal blood transfusion.Methods A total of 45 022 blood samples from the blood donors without payment from June 2007to March 2008 were enrolled in the study.ELISA was applied to determining HBsAg,anti-HCV,anti-HIV,anti-treponema pallidum(anti-TP)and ALT,and then the normal samples for the above parameters(serologically negative for HBsAg.anti-HCV, anti-HIV,anti-TP and ALT)were detected with NAT.The complementarity of ELISA and NAT was analyzed.Results Totally 803 cases(1.98%)were unqualified(serologically positive)out of the 45 022 blood samples.The qualified 36 806samples were further detected with NAT.The results showed 3 cases were HBV-DNA positive,but none was positive for HBV-RNA and HIV-RNA.Conclusion The complementary action of ELISA and NAT is due to different window phase for detected

  10. Label-free and ratiometric detection of nuclei acids based on graphene quantum dots utilizing cascade amplification by nicking endonuclease and catalytic G-quadruplex DNAzyme. (United States)

    Wang, Guang-Li; Fang, Xin; Wu, Xiu-Ming; Hu, Xue-Lian; Li, Zai-Jun


    Herein, we report a ratiometric fluorescence assay based on graphene quantum dots (GQDs) for the ultrasensitive DNA detection by coupling the nicking endonuclease assisted target recycling and the G-quadruplex/hemin DNAzyme biocatalysis for cascade signal amplifications. With o-phenylenediamine acted as the substrate of G-quadruplex/hemin DNAzyme, whose oxidization product (that is, 2,3-diaminophenazine, DAP) quenched the fluorescence intensity of GQDs (at 460nm) obviously, accompanied with the emergence of a new emission of DAP (at 564nm). The ratiometric signal variations at the emission wavelengths of 564 and 460nm (I564/I460) were utilized for label-free, sensitive, and selective detection of target DNA. Utilizing the nicking endonuclease assisted target recycling and the G-quadruplex/hemin DNAzyme biocatalysis for amplified cascade generation of DAP, the proposed bioassay exhibited high sensitivity toward target DNA with a detection limit of 30fM. The method also had additional advantages such as facile preparation and easy operation.

  11. Novel technology for sewage sludge utilization: preparation of amino acids chelated trace elements (AACTE) fertilizer. (United States)

    Liu, Yangsheng; Kong, Sifang; Li, Yaqiong; Zeng, Hui


    This study developed a novel technology for sewage sludge utilization. The bacteria proteins in the sewage sludge were extracted to produce the amino acid chelated trace elements (AACTE) fertilizer by virtue of several chemical processes. Firstly, the sewage sludge was hydrolyzed under hot hydrochloric acid solution to obtain protein solution. The effects of hydrolysis temperature, reaction time and pH on the extraction ratio of protein from the sewage sludge were investigated. Secondly, the protein solution was further hydrolyzed into amino acids under hot acid condition. The effects of the HCl dosage, hydrolysis temperature and reaction time on the yields of amino acids were investigated in detail. Thirdly, the raw amino acids solution was purified by activated carbon decolorization and glacial acetic acid dissolution. Finally, the purified amino acids were used to produce the AACTE fertilizer by chelating with trace elements. Results showed that, under optimum hydrolysis conditions, 78.5% of protein was extracted from the sewage sludge and the amino acids yield was 10-13 g per 100g of dry sludge. The AACTE fertilizer produced was in accordance with China Standard for Amino Acids Foliar Fertilizer. This novel technology is more environmentally friendly compared with the conventional sludge treatments.

  12. RNA amplification of bromodeoxyuridine labeled newborn neurons in the monkey hippocampus. (United States)

    Counts, Scott E; Chen, Er-Yun; Ginsberg, Stephen D; Kordower, Jeffrey H; Mufson, Elliott J


    Neurogenesis has been demonstrated in the adult mammalian hippocampus by the immunohistochemical identification of cells co-labeled with the neuronal marker NeuN and bromodeoxyuridine (BrdU), a marker for DNA synthesis. Whether these newly born neurons exhibit a genetic signature similar to that of existing hippocampal cells remains unknown. Recent advances in single cell RNA amplification techniques provide a unique method for profiling the mRNA complement of cells developed during adult neurogenesis. Standard protocols for identifying BrdU-positive cells requires an acid denaturation step that may preclude the amplification of cellular RNA for expression analysis. We first tested whether the BrdU reaction product was visible in monkey hippocampal tissue following treatment with dilutions of HCl (2-0.2 M) or citric acid (1.0-0.1 M). BrdU-labeled cells were visible only in tissue sections treated with 2 M HCl. RNA amplification was not compromised in cells dual-labeled for BrdU and NeuN using the 2 M HCl acid denaturation step. These cells express mRNAs encoding a wide variety of functional protein subclasses including glutamate receptors. The present study demonstrates for the first time that BrdU immunohistochemisty is compatable with gene array technology in the primate hippocampus to evaluate subclasses of genes in newborn neurons.

  13. Application of Locked Nucleic Acid (LNA) Primer and PCR Clamping by LNA Oligonucleotide to Enhance the Amplification of Internal Transcribed Spacer (ITS) Regions in Investigating the Community Structures of Plant-Associated Fungi. (United States)

    Ikenaga, Makoto; Tabuchi, Masakazu; Kawauchi, Tomohiro; Sakai, Masao


    The simultaneous extraction of host plant DNA severely limits investigations of the community structures of plant-associated fungi due to the similar homologies of sequences in primer-annealing positions between fungi and host plants. Although fungal-specific primers have been designed, plant DNA continues to be excessively amplified by PCR, resulting in the underestimation of community structures. In order to overcome this limitation, locked nucleic acid (LNA) primers and PCR clamping by LNA oligonucleotides have been applied to enhance the amplification of fungal internal transcribed spacer (ITS) regions. LNA primers were designed by converting DNA into LNA, which is specific to fungi, at the forward primer side. LNA oligonucleotides, the sequences of which are complementary to the host plants, were designed by overlapping a few bases with the annealing position of the reverse primer. Plant-specific DNA was then converted into LNA at the shifted position from the 3' end of the primer-binding position. PCR using the LNA technique enhanced the amplification of fungal ITS regions, whereas those of the host plants were more likely to be amplified without the LNA technique. A denaturing gradient gel electrophoresis (DGGE) analysis displayed patterns that reached an acceptable level for investigating the community structures of plant-associated fungi using the LNA technique. The sequences of the bands detected using the LNA technique were mostly affiliated with known isolates. However, some sequences showed low similarities, indicating the potential to identify novel fungi. Thus, the application of the LNA technique is considered effective for widening the scope of community analyses of plant-associated fungi.

  14. Detection of Shigella with helicase-dependent isothermal DNA amplification technology%志贺菌依赖解旋酶DNA恒温扩增技术建立

    Institute of Scientific and Technical Information of China (English)

    王建广; 雷质文; 刘云国; 张健; 姜英辉; 祝素珍; 房保海; 石琰璟


    Objective To establishe a new rapid method to detect Shigella based on helicase-dependent isothermal DNA amplification (HAD). Methods A highly specific set of primers was synthesized to target ipaH gene of Shigella and then HAD condition and the reaction system were optimized simultaneously. Specificity and sensitivity of the method were evaluated. Results The results of all three strains of Shigella were positive,and the othes were negative. The sensitivity was 5. 1×103 cfu/mL,which was similar to the result of PCR method. Conclusion Detecting Shigella with HAD is specific and sensitive as PCR method and has lower instrumental requirement.%目的 利用依赖解旋酶DNA恒温扩增技术(HDA),建立一种快速检测志贺菌(Shigella)的新方法.方法 根据志贺菌的ipaH基因序列设计特异性引物,优化反应体系和反应条件;并对方法进行特异性和灵敏度评价.结果 对21株实验菌株检测,3株志贺菌均为阳性,其余18株非志贺菌均为阴性,灵敏度为5.1×103 cfu/mL,与普通PCR方法检测结果相当.结论 HDA法检测志贺菌具有特异、灵敏及仪器要求低等特点,具有广阔的应用前景.

  15. Detection and identification of 32 Escherichia coli by nuclear acid amplification%32株大肠埃希菌核酸检测鉴定分析

    Institute of Scientific and Technical Information of China (English)

    朱水荣; 潘军航; 余昭; 张政; 王志刚


    目的:对本实验室保存多年的32株大肠埃希菌进行核酸检测鉴定,同时验证所用引物的特异性及改用改良方法的可行性.方法:应用环介导等温扩增(Loop-mediated isothermal amplification,LAMP)技术,参照最新LAMP改良方法,对32株大肠埃希菌及其它9株非大肠埃希菌实验对照株分别进行大肠埃希菌malB、不耐热性肠毒素I(heat labile I enterotoxin,LTI)和耐热性肠毒素I(heat stable I enterotoxin,STI)基因检测.结果:32株大肠埃希菌均扩增出大肠埃希菌malB基因,其中3株均扩增出LTI和STI基因,14株只扩增出LTI基因,1株只扩增出STI基因.整个检测过程仅需1.5 h,可通过肉眼目测绿色钙锰复合物是否生成判断结果.结论:32株大肠埃希菌从基因水平均得到鉴定;试验再次证实参考文献中设计的引物其特异性好;改用改良LAMP方法目测结果直观可行,可免去电泳、拍照两步,具有更快速、简便、经济等特点,极适合基层实验室人员应用于对可疑大肠埃希菌的鉴定检测.

  16. Technology development for phosphoric acid fuel cell powerplant, phase 2 (United States)

    Christner, L.


    The development of materials, cell components, and reformers for on site integrated energy systems is described. Progress includes: (1) heat-treatment of 25 sq cm, 350 sq cm and 1200 sq cm cell test hardware was accomplished. Performance of fuel cells is improved by using this material; (2) electrochemical and chemical corrosion rates of heat-treated and as-molded graphite/phenolic resin composites in phosphoric acid were determined; (3) three cell, 5 in. x 15 in. stacks operated for up to 10,000 hours and 12 in. x 17 in. five cell stacks were tested for 5,000 hours; (4) a three cell 5 in. x 15 in. stack with 0.12 mg Pt/sq cm anodes and 0.25 mg Pt/sq cm cathodes was operated for 4,500 hours; and (5) an ERC proprietary high bubble pressure matrix, MAT-1, was tested for up to 10,000 hours.

  17. Advanced Acid Gas Separation Technology for Clean Power and Syngas Applications

    Energy Technology Data Exchange (ETDEWEB)

    Amy, Fabrice [Air Products and Chemicals Inc., Allentown, PA (United States); Hufton, Jeffrey [Air Products and Chemicals Inc., Allentown, PA (United States); Bhadra, Shubhra [Air Products and Chemicals Inc., Allentown, PA (United States); Weist, Edward [Air Products and Chemicals Inc., Allentown, PA (United States); Lau, Garret [Air Products and Chemicals Inc., Allentown, PA (United States); Jonas, Gordon [Air Products and Chemicals Inc., Allentown, PA (United States)


    Air Products has developed an acid gas removal technology based on adsorption (Sour PSA) that favorably compares with incumbent AGR technologies. During this DOE-sponsored study, Air Products has been able to increase the Sour PSA technology readiness level by successfully operating a two-bed test system on coal-derived sour syngas at the NCCC, validating the lifetime and performance of the adsorbent material. Both proprietary simulation and data obtained during the testing at NCCC were used to further refine the estimate of the performance of the Sour PSA technology when expanded to a commercial scale. In-house experiments on sweet syngas combined with simulation work allowed Air Products to develop new PSA cycles that allowed for further reduction in capital expenditure. Finally our techno economic analysis of the use the Sour PSA technology for both IGCC and coal-to-methanol applications suggests significant improvement of the unit cost of electricity and methanol compared to incumbent AGR technologies.

  18. Study on screening blood donors by nucleic acid amplification technique combined with Enzyme- linked immunosorbent assay%核酸扩增与酶联免疫法联合在血液筛查中的初步应用

    Institute of Scientific and Technical Information of China (English)

    杜勇; 杨亮; 蒋炜; 王佳维; 张哲


    Objective;The purpose of this study was to improve security level of clinical blood transfusion and e-valuate the necessity and practicability of the testing methodology based on nucleic acid amplification technique (NAT) in addition to the regular immunoassay test (EIA). Methods; The samples tested as negative by ELISA were screened by NAT with two work flow ( single detection or combined detection). The NAT - positive samples were further tested by Roche COBAS CAP_CTM system and eletro - cheniluminescence(ECL) system to evaluate the virus load and serological properties. Results; 28 NAT-positive samples were detected in the 20,925 ELISA negative donor samples. All samples were HBV DNA positive and 11 among the 28 samples were serology positive. The remaining risk of HBV infection was 0.13% under the routine EIA test. Conclusion; The risk of HBV infection still remain under the current blood donor screening method using repeated ELISA testing. The introduction of NAT test can help to reduce the risk of transfusion - transmitted disease which has a great value to increase the safety of blood.%目的:在酶联免疫法( enzyme immunoassay,EIA)检测的基础上,探讨HBV核酸扩增检测(nucleic acid amplification testing NAT)技术应用于血液筛查的意义.方法:分别使用两种模式(单检或混检)NAT与EIA两遍检测方式同时进行血液筛查,对NAT阳性标本作进一步做鉴别试验和病毒血清标志物.结果:20925份EIA(-)标本共发现28份核酸三项(HBV DNA、HCV RNA、HIV RNA)呈反应性,均为HBV- DNA,即EIA两遍检测合格后的HBV- DNA阳性率0.13%,检测其中11份血清,乙肝标志物均呈阳性.结论:EIA阴性献血者中仍有极少数的HBV感染者,核酸扩增检测和酶联免疫检测互补能够检测出EIA漏检的HBV携带者,对提高HBsAg阴性血液标本中HBV感染检出率具有重要价值.

  19. Loop mediated isothermal amplification: An innovative gene amplification technique for animal diseases. (United States)

    Sahoo, Pravas Ranjan; Sethy, Kamadev; Mohapatra, Swagat; Panda, Debasis


    India being a developing country mainly depends on livestock sector for its economy. However, nowadays, there is emergence and reemergence of more transboundary animal diseases. The existing diagnostic techniques are not so quick and with less specificity. To reduce the economy loss, there should be a development of rapid, reliable, robust diagnostic technique, which can work with high degree of sensitivity and specificity. Loop mediated isothermal amplification assay is a rapid gene amplification technique that amplifies nucleic acid under an isothermal condition with a set of designed primers spanning eight distinct sequences of the target. This assay can be used as an emerging powerful, innovative gene amplification diagnostic tool against various pathogens of livestock diseases. This review is to highlight the basic concept and methodology of this assay in livestock disease.

  20. Loop mediated isothermal amplification: An innovative gene amplification technique for animal diseases

    Directory of Open Access Journals (Sweden)

    Pravas Ranjan Sahoo


    Full Text Available India being a developing country mainly depends on livestock sector for its economy. However, nowadays, there is emergence and reemergence of more transboundary animal diseases. The existing diagnostic techniques are not so quick and with less specificity. To reduce the economy loss, there should be a development of rapid, reliable, robust diagnostic technique, which can work with high degree of sensitivity and specificity. Loop mediated isothermal amplification assay is a rapid gene amplification technique that amplifies nucleic acid under an isothermal condition with a set of designed primers spanning eight distinct sequences of the target. This assay can be used as an emerging powerful, innovative gene amplification diagnostic tool against various pathogens of livestock diseases. This review is to highlight the basic concept and methodology of this assay in livestock disease.

  1. Amplification of an MFS Transporter Encoding Gene penT Significantly Stimulates Penicillin Production and Enhances the Sensitivity of Penicillium chrysogenum to Phenylacetic Acid

    Institute of Scientific and Technical Information of China (English)

    Jing Yang; Xinxin Xu; Gang Liu


    Penicillin is historically important as the first discovered drug against bacterial infections in human.Although the penicillin biosynthetic pathway and regulatory mechanism have been well studied in Penicillium chrysogenum,the compartnentation and molecular transport of penicillin or its precursors are still poorly understood.In search of the genomic database,more than 830 open reading frames (ORFs) were found to encode transmembrane proteins of P.chrysogenum.In order to investigate their roles on penicillin production,one of them (penT) was selected and cloned.The deduced protein of penT belongs to the major facilitator superfamily (MFS) and contains 12transmembrane spanning domains (TMS).During fermentation,the transcription of penT was greatly induced by penicillin precursors phenylacetic acid (PAA) and phenoxyacetic acid (POA).Knock-down of penT resulted in significant decrease of penicillin production,while over-expression of penT under the promoter of trpC enhanced the penicillin production.Introduction of an additional penT in the wild-type strain of P.chrysogenum doubled the penicillin production and enhanced the sensitivity of P.chrysogenum to the penicillin precursors PAA or POA.These results indicate that penT stimulates penicillin production probably through enhancing the translocation of penicillin precursors across fungal cellular membrane.

  2. Amplification of an MFS transporter encoding gene penT significantly stimulates penicillin production and enhances the sensitivity of Penicillium chrysogenum to phenylacetic acid. (United States)

    Yang, Jing; Xu, Xinxin; Liu, Gang


    Penicillin is historically important as the first discovered drug against bacterial infections in human. Although the penicillin biosynthetic pathway and regulatory mechanism have been well studied in Penicillium chrysogenum, the compartmentation and molecular transport of penicillin or its precursors are still poorly understood. In search of the genomic database, more than 830 open reading frames (ORFs) were found to encode transmembrane proteins of P. chrysogenum. In order to investigate their roles on penicillin production, one of them (penT) was selected and cloned. The deduced protein of penT belongs to the major facilitator superfamily (MFS) and contains 12 transmembrane spanning domains (TMS). During fermentation, the transcription of penT was greatly induced by penicillin precursors phenylacetic acid (PAA) and phenoxyacetic acid (POA). Knock-down of penT resulted in significant decrease of penicillin production, while over-expression of penT under the promoter of trpC enhanced the penicillin production. Introduction of an additional penT in the wild-type strain of P. chrysogenum doubled the penicillin production and enhanced the sensitivity of P. chrysogenum to the penicillin precursors PAA or POA. These results indicate that penT stimulates penicillin production probably through enhancing the translocation of penicillin precursors across fungal cellular membrane.

  3. Using CD-ROM technology to increase folic acid knowledge among physician assistant students. (United States)

    Morgan, Christine; Klein, Diane Austrin; Selbst, Melissa


    The purpose of this study was to examine the effectiveness of incorporating CD-ROM technology to increase the knowledge of folic acid among physician assistant students. Participants included 76 first-year physician assistant students enrolled in a Women's Health course. A pretest and posttest was used to evaluate the knowledge gain after viewing the CD-ROM over a 2-week period. Of the 76 students in the course, 73 completed the pretest and the post-test. Posttest scores were significantly better than pretest scores (t = -11.83; p folic acid information in a clear and effective manner, (2) adequately covered the folic acid information, (3) increased student awareness and knowledge about folic acid, and (4) may promote early commitment by students to recommend daily folic acid intake to their patients.

  4. Reading Out Single-Molecule Digital RNA and DNA Isothermal Amplification in Nanoliter Volumes with Unmodified Camera Phones. (United States)

    Rodriguez-Manzano, Jesus; Karymov, Mikhail A; Begolo, Stefano; Selck, David A; Zhukov, Dmitriy V; Jue, Erik; Ismagilov, Rustem F


    Digital single-molecule technologies are expanding diagnostic capabilities, enabling the ultrasensitive quantification of targets, such as viral load in HIV and hepatitis C infections, by directly counting single molecules. Replacing fluorescent readout with a robust visual readout that can be captured by any unmodified cell phone camera will facilitate the global distribution of diagnostic tests, including in limited-resource settings where the need is greatest. This paper describes a methodology for developing a visual readout system for digital single-molecule amplification of RNA and DNA by (i) selecting colorimetric amplification-indicator dyes that are compatible with the spectral sensitivity of standard mobile phones, and (ii) identifying an optimal ratiometric image-process for a selected dye to achieve a readout that is robust to lighting conditions and camera hardware and provides unambiguous quantitative results, even for colorblind users. We also include an analysis of the limitations of this methodology, and provide a microfluidic approach that can be applied to expand dynamic range and improve reaction performance, allowing ultrasensitive, quantitative measurements at volumes as low as 5 nL. We validate this methodology using SlipChip-based digital single-molecule isothermal amplification with λDNA as a model and hepatitis C viral RNA as a clinically relevant target. The innovative combination of isothermal amplification chemistry in the presence of a judiciously chosen indicator dye and ratiometric image processing with SlipChip technology allowed the sequence-specific visual readout of single nucleic acid molecules in nanoliter volumes with an unmodified cell phone camera. When paired with devices that integrate sample preparation and nucleic acid amplification, this hardware-agnostic approach will increase the affordability and the distribution of quantitative diagnostic and environmental tests.

  5. Performance of self-collected penile-meatal swabs compared to clinician-collected urethral swabs for the detection of Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and Mycoplasma genitalium by nucleic acid amplification assays. (United States)

    Dize, Laura; Barnes, Perry; Barnes, Mathilda; Hsieh, Yu-Hsiang; Marsiglia, Vincent; Duncan, Della; Hardick, Justin; Gaydos, Charlotte A


    Men were enrolled in a study to assess the performance and acceptability of self-collected penile meatal swabs as compared to clinician-collected urethral swabs for sexually transmitted infections (STIs). We expected penile-meatal swabs to perform favorably to urethral swabs for Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Trichomonas vaginalis (TV), and Mycoplasma genitalium (MG) detection by nucleic acid amplification assays (NAATs). Of 203 swab pairs tested; for CT, penile-meatal swab sensitivity was 96.8% and specificity was 98.8%. NG sensitivity and specificity were 100% and 98.9%, respectively. For TV, sensitivity was 85.0% and specificity was 96.7%. For MG sensitivity and specificity were 79.3% and 99.4%, respectively. No significant statistical differences between sample type accuracy (CT: P=0.625; NG: P=0.248; TV: P=0.344; and MG: P=0.070) existed. Most men, 90.1%, reported self-collection of penile-meatal swabs as "Very Easy" or "Easy". Self-collected penile-meatal swabs appeared acceptable for NAAT STI detection and an acceptable collection method by men.

  6. Comparison of levels of human immunodeficiency virus type 1 RNA in plasma as measured by the NucliSens nucleic acid sequence-based amplification and Quantiplex branched-DNA assays. (United States)

    Ginocchio, C C; Tetali, S; Washburn, D; Zhang, F; Kaplan, M H


    This study compared levels of human immunodeficiency virus type 1 RNA in plasma as measured by the Quantiplex branched-DNA and NucliSens nucleic acid sequence-based amplification assays. RNA was detectable in 118 of 184 samples (64.13%) by the Quantiplex assay and in 171 of 184 samples (92.94%) by the NucliSens assay. Regression analysis indicated that a linear relationship existed between the two sets of values (P < 0.0001), although the Quantiplex and NucliSens values were significantly different (P < 0.001), with the NucliSens values being approximately 0.323 log higher. Spearman correlation analysis indicated that the overall changes in patient viral load patterns were highly correlative between the two assays: r = 0.912, P < 0.0001. The lower limits of sensitivity were determined to be approximately 100 copies/ml and 1,200 to 1,400 copies/ml for the NucliSens and Quantiplex assays, respectively.

  7. Multiplex isothermal solid-phase recombinase polymerase amplification for the specific and fast DNA-based detection of three bacterial pathogens. (United States)

    Kersting, Sebastian; Rausch, Valentina; Bier, Frank F; von Nickisch-Rosenegk, Markus


    We report on the development of an on-chip RPA (recombinase polymerase amplification) with simultaneous multiplex isothermal amplification and detection on a solid surface. The isothermal RPA was applied to amplify specific target sequences from the pathogens Neisseria gonorrhoeae, Salmonella enterica and methicillin-resistant Staphylococcus aureus (MRSA) using genomic DNA. Additionally, a positive plasmid control was established as an internal control. The four targets were amplified simultaneously in a quadruplex reaction. The amplicon is labeled during on-chip RPA by reverse oligonucleotide primers coupled to a fluorophore. Both amplification and spatially resolved signal generation take place on immobilized forward primers bount to expoxy-silanized glass surfaces in a pump-driven hybridization chamber. The combination of microarray technology and sensitive isothermal nucleic acid amplification at 38 °C allows for a multiparameter analysis on a rather small area. The on-chip RPA was characterized in terms of reaction time, sensitivity and inhibitory conditions. A successful enzymatic reaction is completed in isothermal nucleic acid amplification with RPA and spatially-resolved signal generation on specific immobilized oligonucleotides.


    As part of the Superfund Innovative Technology Evaluation (SITE) program, an evaluation of the compost-free bioreactor treatment of acid rock drainage (ARD) from the Aspen Seep was conducted at the Leviathan Mine Superfund site located in a remote, high altitude area of Alpine Co...


    Two-page article describing three SITE demonstration projects underway on the Leviathan mine site in California. BiPhasic lime treatment, lime treatment lagoons and compost free BioReactors are being evaluated as innovative technologies for treating acid mine drainage.


    As part of the Superfund Innovative Technology Evaluation (SITE) program, an evaluation of the compost-free bioreactor treatment of acid rock drainage (ARD) from the Aspen Seep was conducted at the Leviathan Mine Superfund site located in a remote, high altitude area of Alpine Co...

  11. Coproduction of acetic acid and electricity by application of microbial fuel cell technology to vinegar fermentation. (United States)

    Tanino, Takanori; Nara, Youhei; Tsujiguchi, Takuya; Ohshima, Takayuki


    The coproduction of a useful material and electricity via a novel application of microbial fuel cell (MFC) technology to oxidative fermentation was investigated. We focused on vinegar production, i.e., acetic acid fermentation, as an initial and model useful material that can be produced by oxidative fermentation in combination with MFC technology. The coproduction of acetic acid and electricity by applying MFC technology was successfully demonstrated by the simultaneous progress of acetic acid fermentation and electricity generation through a series of repeated batch fermentations. Although the production rate of acetic acid was very small, it increased with the number of repeated batch fermentations that were conducted. We obtained nearly identical (73.1%) or larger (89.9%) acetic acid yields than that typically achieved by aerated fermentation (75.8%). The open-cycle voltages measured before and after fermentation increased with the total fermentation time and reached a maximum value of 0.521 V prior to the third batch fermentation. The maximum current and power densities measured in this study (19.1 μA/cm² and 2.47 μW/cm², respectively) were obtained after the second batch fermentation.

  12. Development of a Technology for Treating Wastewater Contaminated with Nitric Acid

    Directory of Open Access Journals (Sweden)

    Liz Mabel Ríos Hidalgo


    Full Text Available The production process of nitroaromatic hazardous compounds, with the generation of acidic wastewater, represents a significant danger for the health and safety of the workers and the environment. The present study is focused on the development of an efficient installation to treat acidic wastewater resulting from the synthesis process of nitroaromatic compound, considering workers safety and environmental criteria. In this research, a detailed study of the different alternatives that can be used for effective and safe treatment of acidic wastewater was performed. The analysis of several technological schemes for the acidic wastewaters neutralization and the selection of the most feasible alternative from a technical-economic point of view were carried out. The simulation and mathematical modeling developed in this research represent a significant advance in the knowledge of this process for working in a much more secure form. The technological scheme of the process was defined, and the design of the main and auxiliary equipment as well as the piping system was carried out using different computational programs. Finally, this paper proposes a technological design for the treatment of acidic wastewater generated by the production process of nitroaromatic compound, which represents the basic criteria for the further design, construction, and equipment installation of the plant.

  13. Towards the routine application of nucleic acid technology for avian disease diagnosis. (United States)

    Cavanagh, D; Mawditt, K; Shaw, K; Britton, P; Naylor, C


    The use of nucleic acid technology (polymerase chain reaction, probing, restriction fragment analysis and nucleotide sequencing) in the study of avian diseases has largely been confined to fundamental analysis and retrospective studies. More recently these approaches have been applied to diagnosis and what one might call real-time epidemiological studies on chickens and turkeys. At the heart of these approaches is the identification and characterisation of pathogens based on their genetic material, RNA or DNA. Among the objectives has been the detection of pathogens quickly combined with the simultaneous identification of serotype, subtype or genotype. Nucleic acid sequencing also gives a degree of characterisation unmatched by other approaches. In this paper we describe the use of nucleic acid technology for the diagnosis and epidemiology of infectious bronchitis virus, turkey rhinotracheitis virus (avian pneumovirus) and Newcastle disease virus.

  14. Camera-based ratiometric fluorescence transduction of nucleic acid hybridization with reagentless signal amplification on a paper-based platform using immobilized quantum dots as donors. (United States)

    Noor, M Omair; Krull, Ulrich J


    Paper-based diagnostic assays are gaining increasing popularity for their potential application in resource-limited settings and for point-of-care screening. Achievement of high sensitivity with precision and accuracy can be challenging when using paper substrates. Herein, we implement the red-green-blue color palette of a digital camera for quantitative ratiometric transduction of nucleic acid hybridization on a paper-based platform using immobilized quantum dots (QDs) as donors in fluorescence resonance energy transfer (FRET). A nonenzymatic and reagentless means of signal enhancement for QD-FRET assays on paper substrates is based on the use of dry paper substrates for data acquisition. This approach offered at least a 10-fold higher assay sensitivity and at least a 10-fold lower limit of detection (LOD) as compared to hydrated paper substrates. The surface of paper was modified with imidazole groups to assemble a transduction interface that consisted of immobilized QD-probe oligonucleotide conjugates. Green-emitting QDs (gQDs) served as donors with Cy3 as an acceptor. A hybridization event that brought the Cy3 acceptor dye in close proximity to the surface of immobilized gQDs was responsible for a FRET-sensitized emission from the acceptor dye, which served as an analytical signal. A hand-held UV lamp was used as an excitation source and ratiometric analysis using an iPad camera was possible by a relative intensity analysis of the red (Cy3 photoluminescence (PL)) and green (gQD PL) color channels of the digital camera. For digital imaging using an iPad camera, the LOD of the assay in a sandwich format was 450 fmol with a dynamic range spanning 2 orders of magnitude, while an epifluorescence microscope detection platform offered a LOD of 30 fmol and a dynamic range spanning 3 orders of magnitude. The selectivity of the hybridization assay was demonstrated by detection of a single nucleotide polymorphism at a contrast ratio of 60:1. This work provides an

  15. Hardness amplification in nondeterministic logspace


    Gupta, Sushmita


    A hard problem is one which cannot be easily computed by efficient algorithms. Hardness amplification is a procedure which takes as input a problem of mild hardness and returns a problem of higher hardness. This is closely related to the task of decoding certain error-correcting codes. We show amplification from mild average case hardness to higher average case hardness for nondeterministic logspace and worst-to-average amplification for nondeterministic linspace. Finally we explore possible ...

  16. Efficiency of membrane technology, activated charcoal, and a micelle-clay complex for removal of the acidic pharmaceutical mefenamic acid. (United States)

    Khalaf, Samer; Al-Rimawi, Fuad; Khamis, Mustafa; Nir, Shlomo; Bufo, Sabino A; Scrano, Laura; Mecca, Gennaro; Karaman, Rafik


    The efficiency of sequential advanced membrane technology wastewater treatment plant towards removal of a widely used non-steroid anti-inflammatory drug (NSAID) mefenamic acid was investigated. The sequential system included activated sludge, ultrafiltration by hollow fibre membranes with 100 kDa cutoff, and spiral wound membranes with 20 kDa cutoff, activated carbon and a reverse osmosis (RO) unit. The performance of the integrated plant showed complete removal of mefenamic acid from spiked wastewater samples. The activated carbon column was the most effective component in removing mefenamic acid with a removal efficiency of 97.2%. Stability study of mefenamic acid in pure water and Al-Quds activated sludge revealed that the anti-inflammatory drug was resistant to degradation in both environments. Batch adsorption of mefenamic acid by activated charcoal and a composite micelle (otadecyltrimethylammonium (ODTMA)-clay (montmorillonite) was determined at 25.0°C. Langmuir isotherm was found to fit the data with Qmax of 90.9 mg g(-1) and 100.0 mg g(-1) for activated carbon and micelle-clay complex, respectively. Filtration experiment by micelle-clay columns mixed with sand in the mg L(-1) range revealed complete removal of the drug with much larger capacity than activated carbon column. The combined results demonstrated that an integration of a micelle-clay column in the plant system has a good potential to improve the removal efficiency of the plant towards NSAID drugs such as mefenamic acid.

  17. Optimization of Extraction Technology of Ellagic Acid from Pomegranate Peels with Orthogonal Experiment

    Institute of Scientific and Technical Information of China (English)


    [Objective] This study aimed to investigate the optimal condition for extrac- tion of ellagic acid from pomegranate peels. [Method] With ellagic acid yield as an indicator, ultrasound extraction method was adopted to extract the ellagic acid from pomegranate peels, and the concentration of ellagic acid was measured by using ul- traviolet spectrophotometry; L9(34) orthogonal experiment was designed with four fac- tors at three levels, to investigate the effect of extraction temperature, extraction du- ration, solid-liquid ratio and ultrasound power on extraction rate of ellagic acid. [Re- sult] The optimal extraction condition for ellagic acid is extraction temperature of 30 ~C, solid-liquid ratio of 1:200, extraction duration of 20 min, and ultrasound power of 50 W. The relationship between primary and secondary factors affecting experimental indicators was solid-liquid ratio 〉 extraction duration 〉 ultrasound power 〉 extraction temperature. [Conclusion] Solid-liquid ratio has the maximum effect on extraction rate of ellagic acid. The ellagic acid extraction technology identified in this study is rea- sonable and feasible.


    Directory of Open Access Journals (Sweden)

    János Csapó


    Full Text Available D-amino acids occurring in dietary proteins originate as a consequence of technological intervention while basic materials are being prepared for consumption. Foodstuffs are the most significant sources of D-amino acids, as in the process of cooking or during the various processing procedures used in the food industry dietary proteins undergo racemisation to a greater or lesser degree. Food stores are now selling increasing quantities of foods (such as breakfast cereals, baked potatoes, liquid and powdered infant foods, meat substitutes and other supplements which in some cases contain substantial quantities of D-amino acids, which in turn possess characteristics harmful with respect to digestion and health. Alkali treatment catalyses the racemisation of optically active amino acids. The degree of racemisation undergone varies from protein to protein, but the relative order of the degree of racemisation of the individual amino acids within proteins shows a high level of similarity. The principal factors influencing racemisation are the pH of the medium, heat treatment, the duration of the application of alkaline treatment and the structure of the respective amino acids. D-amino acids formed in the course of treatment with alkalis or heat give rise to a deterioration in quality and reduce the extent to which food thus treated can be used safely. The presence of D-amino acids in proteins leads to a decrease in digestibility and the availability of the other amino acids. This results in a reduction in the quantities of the L-enantiomers of the essential amino acids, as the peptide bonds cannot split in the normal way. Some D-amino acids can exert an isomer-toxic effect and have the capacity to give rise to changes in the biological effect of lysinoalanine.

  19. 核酸扩增技术在广州市献血员血液筛查中的应用价值%Evaluation of Nucleic Acid Amplification Screening for Blood Donors in Guangzhou

    Institute of Scientific and Technical Information of China (English)

    明凯华; 雷秀霞; 徐邦牢; 罗丽香; 胡洁洁


    【目的】评价核酸扩增技术(NAT)在广州市献血员血液筛查的应用价值。【方法】收集22139名无偿献血员血样,采用酶联免疫吸附试验(ELISA)检测乙型肝炎病毒(HBV)、丙型肝炎病毒(HCV)、梅毒螺旋体(TP)和人免疫缺陷病毒(HIV),并检测谷丙转氨酶(ALT)水平。对四项ELISA检测阴性和ALT≤40U/L者血样,用COBASs201系统进行HBVDNA、HCVRNA、HIVRNA检测。NAT反应性样本、HBV、HCV和HIVELISA检测阳性血样以COBASAmpliScreen试剂盒鉴定。【结果】22139名献血员中,21776例双试剂血清免疫学检测阴性,其中19例为NAT反应阳性,检出率0.087%(19/21776),后经NAT鉴定检测,HBV、HCV和HIV反应阳性检出率分别为0.051%(11/21776)、0.028%(6/21776)和0.009%(2/21776)。126例HBsAg阳性样本中,25例NAT阴性,其中15例HBsAg中和试验阳性,为低水平慢性感染携带者。50例anti‐HCV阳性血样,4例为NAT阴性,补充ELISA检测为anti‐HCV阴性。16例anti‐HIV阳性样本中,7例为NAT阴性,其单样品核酸检测(ID‐NAT)和补充ELISA检测均为anti‐HIV阴性。【结论】NAT血液筛查对HBV、HCV和HIV经ELISA检测阴性样本的检出率较高,在该地开展NAT血液筛查,对于降低输血残余危险有重大意义。少量HBsAg阳性的低水平感染慢性携带者,汇集核酸检测(MP‐NAT)阴性,HBsAg筛查依然是必不可少的筛查手段。%[Objective] To evaluate the application value of nucleic acid amplification technology (NAT) in screening of blood donors in Guangzhou .[Methods] Blood samples from 22 ,139 blood donors in Guangzhou were collected .Enzyme‐linked immunosorbent assay (ELISA) was used to detect the levels of hepatitis B sur‐face antigen (HBsAg ) ,anti‐hepatitis C virus (anti‐HCV ) ,anti‐human immunodeficiency virus (anti‐HIV ) and anti‐Treponemia pallid (anti‐TP) .And the

  20. Simultaneous detection of human mitochondrial DNA and nuclear-inserted mitochondrial-origin sequences (NumtS) using forensic mtDNA amplification strategies and pyrosequencing technology. (United States)

    Bintz, Brittania J; Dixon, Groves B; Wilson, Mark R


    Next-generation sequencing technologies enable the identification of minor mitochondrial DNA variants with higher sensitivity than Sanger methods, allowing for enhanced identification of minor variants. In this study, mixtures of human mtDNA control region amplicons were subjected to pyrosequencing to determine the detection threshold of the Roche GS Junior(®) instrument (Roche Applied Science, Indianapolis, IN). In addition to expected variants, a set of reproducible variants was consistently found in reads from one particular amplicon. A BLASTn search of the variant sequence revealed identity to a segment of a 611-bp nuclear insertion of the mitochondrial control region (NumtS) spanning the primer-binding sites of this amplicon (Nature 1995;378:489). Primers (Hum Genet 2012;131:757; Hum Biol 1996;68:847) flanking the insertion were used to confirm the presence or absence of the NumtS in buccal DNA extracts from twenty donors. These results further our understanding of human mtDNA variation and are expected to have a positive impact on the interpretation of mtDNA profiles using deep-sequencing methods in casework.

  1. Novel technologies provide more engineering strategies for amino acid-producing microorganisms. (United States)

    Gu, Pengfei; Su, Tianyuan; Qi, Qingsheng


    Traditionally, amino acid-producing strains were obtained by random mutagenesis and subsequent selection. With the development of genetic and metabolic engineering techniques, various microorganisms with high amino acid production yields are now constructed by rational design of targeted biosynthetic pathways. Recently, novel technologies derived from systems and synthetic biology have emerged and open a new promising avenue towards the engineering of amino acid production microorganisms. In this review, these approaches, including rational engineering of rate-limiting enzymes, real-time sensing of end-products, pathway optimization on the chromosome, transcription factor-mediated strain improvement, and metabolic modeling and flux analysis, were summarized with regard to their application in microbial amino acid production.

  2. Confirmation of Structural Variants of Hemoglobin Using Acid Gel in Hydrasis Technology

    Directory of Open Access Journals (Sweden)

    Jacqueline Pérez Rodríguez


    Full Text Available Background: The National Medical Genetics Center has conducted a research on the major hemoglobin abnormalities of clinical interest (HbS, HbC present in pregnant women in the province of Artemisa, using Hydrasis technology with alkaline agarose gels. The use of these gels does not allow distinguishing hemoglobin S from hemoglobin D or hemoglobin C from hemoglobin E, as these hemoglobins migrate in the same position. Objective: to assess the use of acid gel to differentiate haemoglobin D from haemoglobin E by their mobility in hemoglobin electrophoresis. Methods: a descriptive study was conducted using hemoglobin electrophoresis with Hydrasis technology to analyze 200 biological samples of whole blood from pregnant women and individuals with sicklemia or carrying the disease. The acceptance limits included a correlation of electrophoresis run in acid gel in relation to alkaline gel, b correct migration of the hemoglobin bands and c good interpretation of the results. Results: 98 % of the samples analyzed with acid gel showed correspondence with those obtained with alkaline gel. It was not possible to determine and confirm the hemoglobin variant in three samples. Conclusions: the use of acid gels in electrophoresis run with the Hydrasis technology provided results which confirm the diagnosis of hemoglobinopathies.

  3. Quality control for quantitative PCR based on amplification compatibility test. (United States)

    Tichopad, Ales; Bar, Tzachi; Pecen, Ladislav; Kitchen, Robert R; Kubista, Mikael; Pfaffl, Michael W


    Quantitative qPCR is a routinely used method for the accurate quantification of nucleic acids. Yet it may generate erroneous results if the amplification process is obscured by inhibition or generation of aberrant side-products such as primer dimers. Several methods have been established to control for pre-processing performance that rely on the introduction of a co-amplified reference sequence, however there is currently no method to allow for reliable control of the amplification process without directly modifying the sample mix. Herein we present a statistical approach based on multivariate analysis of the amplification response data generated in real-time. The amplification trajectory in its most resolved and dynamic phase is fitted with a suitable model. Two parameters of this model, related to amplification efficiency, are then used for calculation of the Z-score statistics. Each studied sample is compared to a predefined reference set of reactions, typically calibration reactions. A probabilistic decision for each individual Z-score is then used to identify the majority of inhibited reactions in our experiments. We compare this approach to univariate methods using only the sample specific amplification efficiency as reporter of the compatibility. We demonstrate improved identification performance using the multivariate approach compared to the univariate approach. Finally we stress that the performance of the amplification compatibility test as a quality control procedure depends on the quality of the reference set.

  4. Parametric nanomechanical amplification at very high frequency. (United States)

    Karabalin, R B; Feng, X L; Roukes, M L


    Parametric resonance and amplification are important in both fundamental physics and technological applications. Here we report very high frequency (VHF) parametric resonators and mechanical-domain amplifiers based on nanoelectromechanical systems (NEMS). Compound mechanical nanostructures patterned by multilayer, top-down nanofabrication are read out by a novel scheme that parametrically modulates longitudinal stress in doubly clamped beam NEMS resonators. Parametric pumping and signal amplification are demonstrated for VHF resonators up to approximately 130 MHz and provide useful enhancement of both resonance signal amplitude and quality factor. We find that Joule heating and reduced thermal conductance in these nanostructures ultimately impose an upper limit to device performance. We develop a theoretical model to account for both the parametric response and nonequilibrium thermal transport in these composite nanostructures. The results closely conform to our experimental observations, elucidate the frequency and threshold-voltage scaling in parametric VHF NEMS resonators and sensors, and establish the ultimate sensitivity limits of this approach.

  5. Efficient audio power amplification - challenges

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Michael A.E.


    For more than a decade efficient audio power amplification has evolved and today switch-mode audio power amplification in various forms are the state-of-the-art. The technical steps that lead to this evolution are described and in addition many of the challenges still to be faced and where extensive research and development are needed is covered. (au)

  6. Potential effects of clean coal technologies on acid precipitation, greenhouse gases, and solid waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Blasing, T.J.; Miller, R.L.; McCold, L.N.


    The US Department of Energy`s (DOE`s) Clean Coal Technology Demonstration Program (CCTDP) was initially funded by Congress to demonstrate more efficient, economically feasible, and environmentally acceptable coal technologies. Although the environmental focus at first was on sulfur dioxide (SO{sub 2}) and nitrogen oxides (NO{sub x}) because their relationship to acid precipitation, the CCTDP may also lead to reductions in carbon dioxide (CO{sub 2}) emissions and in the volume of solid waste produced, compared with conventional technologies. The environmental effects of clean coal technologies (CCTs) depend upon which (if any) specific technologies eventually achieve high acceptance in the marketplace. In general, the repowering technologies and a small group of retrofit technologies show the most promise for reducing C0{sub 2} emissions and solid waste. These technologies also compare favorably with other CCTs in terms of SO{sub 2} and NO{sub x} reductions. The upper bound for CO{sup 2} reductions in the year 2010 is only enough to reduce global ``greenhouse`` warming potential by about 1%. However, CO{sub 2} emissions come from such variety of sources around the globe that no single technological innovation or national policy change could realistically be expected to reduce these emissions by more than a few percent. Particular CCTs can lead to either increases or decreases in the amount of solid waste produced. However, even if decreases are not achieved, much of the solid waste from clean coal technologies would be dry and therefore easier to dispose of than scrubber sludge.

  7. Peracetic acid as an alternative disinfection technology for wet weather flows. (United States)

    Coyle, Elizabeth E; Ormsbee, Lindell E; Brion, Gail M


    Rain-induced wet weather flows (WWFs) consist of combined sewer overflows, sanitary sewer overflows, and stormwater, all of which introduce pathogens to surface waters when discharged. When people come into contact with the contaminated surface water, these pathogens can be transmitted resulting in severe health problems. As such, WWFs should be disinfected. Traditional disinfection technologies are typically cost-prohibitive, can yield toxic byproducts, and space for facilities is often limited, if available. More cost-effective alternative technologies, requiring less space and producing less harmful byproducts are currently being explored. Peracetic acid (PAA) was investigated as one such alternative and this research has confirmed the feasibility and applicability of using PAA as a disinfectant for WWFs. Peracetic acid doses ranging from 5 mg/L to 15 mg/L over contact times of 2 to 10 minutes were shown to be effective and directly applicable to WWF disinfection.

  8. Biodiesel production using fatty acids from food industry waste using corona discharge plasma technology. (United States)

    Cubas, A L V; Machado, M M; Pinto, C R S C; Moecke, E H S; Dutra, A R A


    This article aims to describe an alternative and innovative methodology to transform waste, frying oil in a potential energy source, the biodiesel. The biodiesel was produced from fatty acids, using a waste product of the food industry as the raw material. The methodology to be described is the corona discharge plasma technology, which offers advantages such as acceleration of the esterification reaction, easy separation of the biodiesel and the elimination of waste generation. The best conditions were found to be an oil/methanol molar ratio of 6:1, ambient temperature (25 °C) and reaction time of 110 min and 30 mL of sample. The acid value indicates the content of free fatty acids in the biodiesel and the value obtained in this study was 0.43 mg KOH/g. Peaks corresponding to octadecadienoic acid methyl ester, octadecanoic acid methyl ester and octadecenoic acid methyl ester, from the biodiesel composition, were identified using GC-MS. A major advantage of this process is that the methyl ester can be obtained in the absence of chemical catalysts and without the formation of the co-product (glycerin).


    Directory of Open Access Journals (Sweden)

    Amanda de Souza Motta


    Full Text Available Eacters of coccus or rods Gram-positive, catalase negative, non-sporulating, which produce lactic acid as the major end product during the fermentation of carbohydrates. When applied on food, provides beneficial effects to consumers through its functional and technological properties. With this the present review article, explore the potential application of lactic acid bacteria in food. The following genera are considered the principal lactic acid bacteria: Aerococcus, Carnobacterium, Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Oenococcus, Pediococcus, Streptococcus, Tetragenococcus, Vagococcus and Weissella. These cultures have been used as starter or adjunct cultures for the fermentation of foods and beverages due to their contributions to the sensorial characteristics of these products and by microbiological stability. Their probiotic properties have also been investigated. More recent studies by indigenous cultures have received increased attention in light of the search for isolated cultures of a given raw material and a certain region. These microorganisms are being investigated for its functional and technological potential that may be applied in product development with its own characteristics and designation of origin. Those properties will be discussed in the present review in order to highlight the performance of these bacteria and the high degree of control over the fermentation process and standardization of the final product. The use of autochthonous cultures will be considered due the increase of studies of new cultures of lactic acid bacteria isolated of milk and meat of distinct products.

  10. Application of acid-catalyzed hydrolysis of dispersed organic solvent in developing new microencapsulation process technology. (United States)

    Lee, Honghwa; Lee, Sunhwa; Bhattacharjee, Himanshu; Sah, Hongkee


    The aim of this study was to evaluate a new microencapsulation technology employing an acid-catalyzed solvent extraction method in conjunction to an emulsion-based microencapsulation process. Its process consisted of emulsifying a dispersed phase of poly(D,L-lactide-co-glycolide) and isopropyl formate in an aqueous phase. This step was followed by adding hydrochloric acid to the resulting oil-in-water emulsion, in order to initiate the hydrolysis of isopropyl formate dissolved in the aqueous phase. Its hydrolysis caused the liberation of water-soluble species, that is, isopropanol and formic acid. This event triggered continual solvent leaching out of emulsion droplets, thereby initiating microsphere solidification. This new processing worked well for encapsulation of progesterone and ketoprofen that were chosen as a nonionizable model drug and a weakly acidic one, respectively. Furthermore, the structural integrity of poly(D,L-lactide-co-glycolide) was retained during microencapsulation. The new microencapsulation technology, being conceptually different from previous approaches, might be useful in preparing various polymeric particles.

  11. RNA amplification for successful gene profiling analysis

    Directory of Open Access Journals (Sweden)

    Wang Ena


    Full Text Available Abstract The study of clinical samples is often limited by the amount of material available to study. While proteins cannot be multiplied in their natural form, DNA and RNA can be amplified from small specimens and used for high-throughput analyses. Therefore, genetic studies offer the best opportunity to screen for novel insights of human pathology when little material is available. Precise estimates of DNA copy numbers in a given specimen are necessary. However, most studies investigate static variables such as the genetic background of patients or mutations within pathological specimens without a need to assess proportionality of expression among different genes throughout the genome. Comparative genomic hybridization of DNA samples represents a crude exception to this rule since genomic amplification or deletion is compared among different specimens directly. For gene expression analysis, however, it is critical to accurately estimate the proportional expression of distinct RNA transcripts since such proportions directly govern cell function by modulating protein expression. Furthermore, comparative estimates of relative RNA expression at different time points portray the response of cells to environmental stimuli, indirectly informing about broader biological events affecting a particular tissue in physiological or pathological conditions. This cognitive reaction of cells is similar to the detection of electroencephalographic patterns which inform about the status of the brain in response to external stimuli. As our need to understand human pathophysiology at the global level increases, the development and refinement of technologies for high fidelity messenger RNA amplification have become the focus of increasing interest during the past decade. The need to increase the abundance of RNA has been met not only for gene specific amplification, but, most importantly for global transcriptome wide, unbiased amplification. Now gene

  12. Loop-mediated isothermal amplification technology in the rapid detection of Bacillus anthracis%环介导等温扩增技术在快速检测炭疽芽胞杆菌中的应用

    Institute of Scientific and Technical Information of China (English)

    段圣亮; 陆晔; 田桢干; 王桂江


    The present paper aims to establish a rapid detection method for Bacillus anthracis. The primes were designed according to Bacillus anthracis strain-specific gene fragment, and loop-mediated isothermal amplification (LAMP) was used to establish the detection method . The results showed that LAMP can effectively identify the specific target bacteria with sensitivity of 102 -103 CFU/ml. It is suggested that LAMP is simple and fast in detection of bioterrorism bacteria such as Bacillus anthracis in acidic , alkaline and viscous media. High-salt environment influences LAMP results , so it is necessary to effectively remove salt out of nucleic acid before application of LAMP .%本文旨在建立适合国境口岸现场应用的生物恐怖防控快速检测方法,从而保障口岸安全.针对生物恐怖炭疽芽胞杆菌,选择目标菌种特异性基因片段,设计引物,运用环介导等温扩增(LAMP)技术建立一套简便、高效的检测方法,并模拟生物恐怖炭疽芽胞杆菌可能存在的基质条件,评价LAMP技术在快速筛查中的适用性.结果显示,LAMP技术排查生物恐怖炭疽芽胞杆菌简便、快速、特异,检测灵敏度为102~103 CFU/ml;且能有效检出在偏酸、偏碱及黏稠基质中的炭疽芽胞杆菌.而高盐环境对该反应影响较大,有必要采用能有效去除盐分的核酸抽提方法.

  13. Comparison between NuGEN's WT-Ovation Pico and one-direct amplification systems. (United States)

    Morse, Alison M; Carballo, Valentina; Baldwin, Donald A; Taylor, Christopher G; McIntyre, Lauren M


    Differential gene expression between groups of homogenous cell types is a biological question whose time has come. RNA can be extracted from small numbers of cells, such as those isolated by laser-capture microdissection, but the small amounts obtained often require amplification to enable whole genome transcriptome profiling by technologies such as microarray analysis and RNA-seq. Recently, advances in amplification procedures make amplification directly from whole cell lysates possible. The aim of this study was to compare two amplification systems for variations in observed RNA abundance attributable to the amplification procedure for use with small quantities of cells isolated by laser-capture microdissection. Arabidopsis root cells undergoing giant cell formation as a result of nematode infestation and uninfested control root cells were laser-captured and used to evaluate two amplification systems. One, NuGEN's WT-Ovation Pico (Pico) amplification system, uses total RNA as starting material, and the other, NuGEN's WT-One-Direct (One-Direct) amplification system, uses lysate containing the captured cells. The reproducibility of whole genome transcript profiling and correlations of both systems were investigated after microarray analysis. The One-Direct system was less reproducible and more variable than the Pico system. The Pico amplification kit resulted in the detection of thousands of differentially expressed genes between giant cells and control cells. This is in marked contrast to the relatively few genes detected after amplification with the One-Direct amplification kit.

  14. One-pot isothermal DNA amplification Hybridisation and detection by a disc-based method



    [EN] An integrated sensor comprising isothermal DNA amplification and in situ detection is presented. The method principle is based on recombinase polymerase amplification (RPA) and detection in the microarray format by compact disc technology as a high-throughput sensing platform. Primers were immobilised on the polycarbonate surface of digital versatile discs (DVD) and, after hemi-nested amplification, multiplexing identification of each tethered product was achieved by optical scanning wit...

  15. Next generation Chirped Pulse Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Nees, J.; Biswal, S.; Mourou, G. [Univ. Michigan, Center for Ultrafast Optical Science, Ann Arbor, MI (United States); Nishimura, Akihiko; Takuma, Hiroshi


    The limiting factors of Chirped Pulse Amplification (CPA) are discussed and experimental results of CPA in Yb:glass regenerative amplifier are given. Scaling of Yb:glass to the petawatt level is briefly discussed. (author)

  16. Atmospheric leaching of nickel and cobalt from nickel saprolite ores using the Starved Acid Leaching Technology (United States)

    Dreisinger, David


    There is great potential to recover nickel from below cut-off grade nickel saprolite ores using the Starved Acid Leach Technology (SALT). Nickel saprolite ores are normally mined as feed to Fe-Ni smelters or Ni matte smelting operations. The smelting processes typically require high Ni cut-off grades of 1.5 to 2.2% Ni, depending on the operation. These very high cutoff grades result in a significant portion of the saprolite profile being regarded as "waste" and hence having little to no value. The below cut-off grade (waste) material can be processed by atmospheric acid leaching with "starvation" levels of acid addition. The leached nickel and cobalt may be recovered as a mixed hydroxide (or alternate product). The mixed hydroxide may be added to the saprolite smelting operation feed system to increase the nickel production of the smelter or may be refined separately. The technical development of the SALT process will be described along with an economic summary. The SALT process has great potential to treat many Indonesian Nickel ores that are too low a grade for current technology.

  17. A review on the current status and production technology of {sup 32,} {sup 33}P-orthophosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ul Jae; Han, Hyun Soo; Cho, Woon Kap; Kuznetsov, Rostislav A


    The current status of {sup 32}, {sup 33}P-Orthophosphoric acid production technology is reviewed. The following aspects of the technology are covered: - production of phosphorus-32 and phosphorus-33 using various nuclear reactions; - chemical properties of sulfur and phosphorus effecting the technology of radioactive phosphorus production; - chemical state of {sup 32}, {sup 33}P in neutron irradiated sulfur; - the technology of radioactive phosphorus isolation from neutron irradiated target and orthophosphoric acid production; - purification of {sup 32}, {sup 33}P-orthophosphoric acid from impurities and some related problems, like the nature of impurities, the storage of the final product, etc. - the quality control procedures of carrier-free ({sup 32}, {sup 33}P)-orthophosphoric acid preparations.

  18. Optical Parametric Amplification for High Peak and Average Power

    Energy Technology Data Exchange (ETDEWEB)

    Jovanovic, I


    Optical parametric amplification is an established broadband amplification technology based on a second-order nonlinear process of difference-frequency generation (DFG). When used in chirped pulse amplification (CPA), the technology has been termed optical parametric chirped pulse amplification (OPCPA). OPCPA holds a potential for producing unprecedented levels of peak and average power in optical pulses through its scalable ultrashort pulse amplification capability and the absence of quantum defect, respectively. The theory of three-wave parametric interactions is presented, followed by a description of the numerical model developed for nanosecond pulses. Spectral, temperature and angular characteristics of OPCPA are calculated, with an estimate of pulse contrast. An OPCPA system centered at 1054 nm, based on a commercial tabletop Q-switched pump laser, was developed as the front end for a large Nd-glass petawatt-class short-pulse laser. The system does not utilize electro-optic modulators or multi-pass amplification. The obtained overall 6% efficiency is the highest to date in OPCPA that uses a tabletop commercial pump laser. The first compression of pulses amplified in highly nondegenerate OPCPA is reported, with the obtained pulse width of 60 fs. This represents the shortest pulse to date produced in OPCPA. Optical parametric amplification in {beta}-barium borate was combined with laser amplification in Ti:sapphire to produce the first hybrid CPA system, with an overall conversion efficiency of 15%. Hybrid CPA combines the benefits of high gain in OPCPA with high conversion efficiency in Ti:sapphire to allow significant simplification of future tabletop multi-terawatt sources. Preliminary modeling of average power limits in OPCPA and pump laser design are presented, and an approach based on cascaded DFG is proposed to increase the average power beyond the single-crystal limit. Angular and beam quality effects in optical parametric amplification are modeled

  19. [Optimization of extraction technology for salidroside, tyrosol, crenulatin and gallic acid in Rhodiolae Crenulatae Radix et Rhizoma with orthogonal test]. (United States)

    Luo, Xin; Wang, Xue-jing; Zhao, Yi-wu; Huang, Wen-zhe; Wang, Zhen-zhong; Xiao, Wei


    The extracting technology of salidroside, tyrosol, crenulatin and gallic acid from Rhodiolae Crenulatae Radix et Rhizoma was optimized. With extraction rate of salidroside, tyrosol, crenulatin and gallic acid as indexes, orthogonal test was used to evaluate effect of 4 factors on extracting technology, including concentration of solvent, the dosage of solvent, duration of extraction, and frequency of extraction. The results showed that, the best extracting technology was to extract in 70% alcohol with 8 times the weight of herbal medicine for 2 times, with 3 hours once. High extraction rate of salidroside, tyrosol, crenulatin and gallic acid were obtained with the present technology. The extracting technology was stable and feasible with high extraction rate of four compounds from Rhodiolae Crenulatae Radix et Rhizoma, it was suitable for industrial production.

  20. Genetic diversity, safety and technological characterization of lactic acid bacteria isolated from artisanal Pico cheese. (United States)

    Domingos-Lopes, M F P; Stanton, C; Ross, P R; Dapkevicius, M L E; Silva, C C G


    A total of 114 lactic acid bacteria were isolated at one and 21 days of ripening from a traditional raw cow's milk cheese without the addition of starter culture, produced by three artisanal cheese-makers in Azores Island (Pico, Portugal). Identification to species and strain level was accomplished by16S rRNA gene and PFGE analysis. Carbohydrate utilization profiles were obtained with the relevant API kits. Isolates were evaluated according to safety and technological criteria. The most frequently observed genus identified by 16S rRNA sequencing analysis was Enterococcus, whereas API system mostly identified Lactobacillus. The highest percentages of antibiotic resistance were to nalidixic acid (95%), and aminoglycosides (64-87%). All isolates were sensitive to several beta-lactam antibiotics and negative for histamine and DNase production. Gelatinase activity was detected in 49.1% of isolates, 43% were able to degrade casein and 93% were α-hemolytic. Most enterococci presented virulence genes, such as gelE, asaI, ace. Diacetyl production was found to be species dependent and one strain (Leu. citreum) produced exopolysaccharides. Selected strains were further studied for technological application and were found to be slow acid producers in milk and experimental cheeses, a desirable trait for adjunct cultures. Two strains were selected on the basis of technological and safety application as adjunct cultures in cheese production and presented the best cheese aroma and flavor in consumer preference tests. This is the first effort to characterize Pico cheese LAB isolates for potential application as adjunct cultures; the results suggest the potential of two strains to improve the quality of this traditional raw milk product.

  1. Inhibition of fungal spore adhesion by zosteric Acid as the basis for a novel, nontoxic crop protection technology. (United States)

    Stanley, Michele S; Callow, Maureen E; Perry, Ruth; Alberte, Randall S; Smith, Robert; Callow, James A


    ABSTRACT To explore the potential for nontoxic crop protection technologies based on the inhibition of fungal spore adhesion, we have tested the effect of synthetic zosteric acid (p-(sulfo-oxy) cinnamic acid), a naturally occurring phenolic acid in eelgrass (Zostera marina L.) plants, on spore adhesion and infection in two pathosystems: rice blast caused by Magnaporthe grisea and bean anthracnose caused by Colletotrichum lindemuthianum. We have shown that zosteric acid inhibits spore adhesion to model and host leaf surfaces and that any attached spores fail to develop appressoria, and consequently do not infect leaf cells. Low concentrations of zosteric acid that are effective in inhibiting adhesion are not toxic to either fungus or to the host. The inhibition of spore adhesion in the rice blast pathogen is fully reversible. On plants, zosteric acid reduced (rice) or delayed (bean) lesion development. These results suggest that there is potential for novel and environmentally benign crop protection technologies based on manipulating adhesion.

  2. Advanced Acid Gas Separation Technology for the Utilization of Low Rank Coals

    Energy Technology Data Exchange (ETDEWEB)

    Kloosterman, Jeff


    Air Products has developed a potentially ground-breaking technology – Sour Pressure Swing Adsorption (PSA) – to replace the solvent-based acid gas removal (AGR) systems currently employed to separate sulfur containing species, along with CO{sub 2} and other impurities, from gasifier syngas streams. The Sour PSA technology is based on adsorption processes that utilize pressure swing or temperature swing regeneration methods. Sour PSA technology has already been shown with higher rank coals to provide a significant reduction in the cost of CO{sub 2} capture for power generation, which should translate to a reduction in cost of electricity (COE), compared to baseline CO{sub 2} capture plant design. The objective of this project is to test the performance and capability of the adsorbents in handling tar and other impurities using a gaseous mixture generated from the gasification of lower rank, lignite coal. The results of this testing are used to generate a high-level pilot process design, and to prepare a techno-economic assessment evaluating the applicability of the technology to plants utilizing these coals.

  3. Uncertainties in Site Amplification Estimation (United States)

    Cramer, C. H.; Bonilla, F.; Hartzell, S.


    Typically geophysical profiles (layer thickness, velocity, density, Q) and dynamic soil properties (modulus and damping versus strain curves) are used with appropriate input ground motions in a soil response computer code to estimate site amplification. Uncertainties in observations can be used to generate a distribution of possible site amplifications. The biggest sources of uncertainty in site amplifications estimates are the uncertainties in (1) input ground motions, (2) shear-wave velocities (Vs), (3) dynamic soil properties, (4) soil response code used, and (5) dynamic pore pressure effects. A study of site amplification was conducted for the 1 km thick Mississippi embayment sediments beneath Memphis, Tennessee (see USGS OFR 04-1294 on the web). In this study, the first three sources of uncertainty resulted in a combined coefficient of variation of 10 to 60 percent. The choice of soil response computer program can lead to uncertainties in median estimates of +/- 50 percent. Dynamic pore pressure effects due to the passing of seismic waves in saturated soft sediments are normally not considered in site-amplification studies and can contribute further large uncertainties in site amplification estimates. The effects may range from dilatancy and high-frequency amplification (such as observed at some sites during the 1993 Kushiro-Oki, Japan and 2001 Nisqually, Washington earthquakes) or general soil failure and deamplification of ground motions (such as observed at Treasure Island during the 1989 Loma Prieta, California earthquake). Examples of two case studies using geotechnical data for downhole arrays in Kushiro, Japan and the Wildlife Refuge, California using one dynamic code, NOAH, will be presented as examples of modeling uncertainties associated with these effects. Additionally, an example of inversion for estimates of in-situ dilatancy-related geotechnical modeling parameters will be presented for the Kushiro, Japan site.

  4. Field experience and improvements with thin tubular-plate lead/acid technology

    Energy Technology Data Exchange (ETDEWEB)

    Merz, K.D. [CMP Batteries, Bolton (United Kingdom)


    The Classic 25 is the product name for a motive-power lead/acid cell using thin positive tubular plates. This cell was developed for use in electric vehicles and other applications where high specific energy and reliable cycle life is required. It would appear that the best approach is to provide a lead/acid battery that has the highest specific energy while still maintaining excellent cycle life. This technology was implemented by use of 6 V modules, followed by a 2-V design. Since this was first introduced in 1989, more than 20 000 cells and monoblocs have been delivered to various electric vehicle applications such as vans, trucks, and buses. The field experience with this product is therefore excellent, and development is continuing on the battery design and manufacturing techniques to improve performance and life even further. Today, a wide range of products using this technology is available, and the latest developments are a new 6 V monobloc and some maintenance-free cells. (orig.)

  5. Dual-coated lactic acid bacteria: an emerging innovative technology in the field of probiotics. (United States)

    Alvarez-Calatayud, Guillermo; Margolles, Abelardo


    Probiotics are living micro-organisms that do not naturally have shelf life, and normally are weakly protected against the digestive action of the GI tract. A new dual coating technology has been developed in an effort to maximize survival, that is, to be able to reach the intestine alive and in sufficient numbers to confer the beneficial health effects on the host. Dual-coating of lactic acid bacteria (LAB) is the result of fourth-generation coating technology for the protection of these bacteria at least 100-fold or greater than the uncoated LAB. This innovative technique involves a first pH-dependent protein layer that protects bacteria from gastric acid and bile salt, and a second polysaccharide matrix that protects bacteria from external factors, such as humidity, temperature and pressure, as well as the digestive action during the passage through the GI tract. Dual-coated probiotic formulation is applicable to different therapeutic areas, including irritable bowel syndrome, atopic dermatitis, acute diarrhea, chronic constipation, Helicobacter pylori eradication, and prevention of antibiotic-associated diarrhea. An updated review of the efficacy of doubly coated probiotic strains for improving bacterial survival in the intestinal tract and its consequent clinical benefits in humans is here presented.

  6. Amplification of Short Pulse High Power UV Laser

    Institute of Scientific and Technical Information of China (English)


    At recent year, with the development of CPA and other amplification technology, laser intensity achieves great increase and laser power can be high to PW(105) now, this ultrashort pulse lasers offer scientists a route to investigate laser-matter interaction in an absolute new regime.So far the researches on ultrashort pulse laser-matter interaction concentrated on infrared regime, yet ultraviolet laser has the advantage in intense field physics and ICF researches for its short wavelength and less nonlinear effects. KrF excimer is the best medium in UV ultrashort pulse amplification for its small saturation energy and high contrast ratio accessible.

  7. Review and assessment of technologies for the separation of cesium from acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Orth, R.J.; Brooks, K.P.; Kurath, D.E.


    A preliminary literature survey has been conducted to identify and evaluate methods for the separation of cesium from acidic waste. The most promising solvent extraction, precipitation, and ion exchange methods, along with some of the attributes for each method, are listed. The main criteria used in evaluating the separation methods were as follows: (1) good potential for cesium separation must be demonstrated (i.e., cesium decontamination factors on the order of 50 to 100). (2) Good selectivity for cesium over bulk components must be demonstrated. (3) The method must show promise for evolving into a practical and fairly simple process. (4) The process should be safe to operate. (5) The method must be robust (i.e., capable of separating cesium from various acidic waste types). (6) Secondary waste generation must be minimized. (7) The method must show resistance to radiation damage. The most promising separation methods did not necessarily satisfy all of the above criteria, thus key areas requiring further development are suggested for each method. The report discusses in detail these and other areas requiring further development, as well as alternative solvent extraction, precipitation, ion exchange, and {open_quote}other{close_quote} technologies that, based on current information, show less promise for the separation of cesium from acidic wastes because of significant process limitations. When appropriate, the report recommends areas of future development.

  8. Method for chemical amplification based on fluid partitioning in an immiscible liquid

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Brian L.; Colston, Bill W.; Elkin, Christopher J.


    A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

  9. A DNA nanomachine based on rolling circle amplification-bridged two-stage exonuclease III-assisted recycling strategy for label-free multi-amplified biosensing of nucleic acid. (United States)

    Xue, Qingwang; Lv, Yanqin; Cui, Hui; Gu, Xiaohong; Zhang, Shuqiu; Liu, Jifeng


    An autonomous DNA nanomachine based on rolling circle amplification (RCA)-bridged two-stage exonuclease III (Exo III)-induced recycling amplification (Exo III-RCA-Exo III) was developed for label-free and highly sensitive homogeneous multi-amplified detection of DNA combined with sensitive fluorescence detection technique. According to the configuration, the analysis of DNA is accomplished by recognizing the target to a unlabeled molecular beacon (UMB) that integrates target-binding and signal transducer within one multifunctional design, followed by the target-binding of UMB in duplex DNA removed stepwise by Exo III accompanied by the releasing of target DNA for the successive hybridization and cleavage process and autonomous generation of the primer that initiate RCA process with a rational designed padlock DNA. The RCA products containing thousands of repeated catalytic sequences catalytically hybridize with a hairpin reporter probe that includes a "caged" inactive G-quadruplex sequence (HGP) and were then detected by Exo III-assisted recycling amplification, liberating the active G-quadruplex and generating remarkable ZnPPIX/G-quadruplex fluorescence signals with the help of zinc(II)-protoporphyrin IX (ZnPPIX). The proposed strategy showed a wide dynamic range over 7 orders of magnitude with a low limit of detection of 0.51 aM. In addition, this designed protocol can discriminate mismatched DNA from perfectly matched target DNA, and holds a great potential for early diagnosis in gene-related diseases.

  10. Isothermal Amplification of Insect DNA (United States)

    The loop-mediated isothermal amplification of DNA (LAMP) method can amplify a target DNA sequence at a constant temperature in about one hour. LAMP has broad application in agriculture and medicine because of the need for rapid and inexpensive diagnoses. LAMP eliminates the need for temperature cycl...

  11. Treatment of allergic asthma by targeting transcription factors using nucleic-acid based technologies. (United States)

    Sel, Serdar; Henke, Wolfgang; Dietrich, Alexander; Herz, Udo; Renz, Harald


    There is considerable evidence that T-helper 2 (Th2) cells play a central role in the pathogenesis of allergic diseases such as bronchial asthma, hay fever or food allergy. The differentiation of naïve T cells into Th2 cells producing a specific pattern of cytokines is tightly controlled and regulated by transcription factors. Thus down-regulation of mRNA-levels of a single transcription factor leads to a "knock-down" of several mediators simultaneously, representing an advantage compared to earlier approaches involving down-regulation of one intercellular inflammatory mediator, which is unlikely to influence all pathophysiological aspects of the disease. We review the impact of specific and master transcription factors involved in Th2 cell commitment and evaluate approaches for the down-regulation of these proteins by degradation of their mRNA using nucleic-acid based technologies including antisense oligonucleotides, ribozymes, DNAzymes, decoys oligonucleotides and RNA interference.

  12. Technological and functional applications of low-calorie sweeteners from lactic acid bacteria. (United States)

    Patra, F; Tomar, S K; Arora, S


    Lactic acid bacteria (LAB) have been extensively used for centuries as starter cultures to carry out food fermentations and are looked upon as burgeoning "cell factories" for production of host of functional biomolecules and food ingredients. Low-calorie sugars have been a recent addition and have attracted a great deal of interest of researchers, manufacturers, and consumers for varied reasons. These sweeteners also getting popularized as low-carb sugars have been granted generally recommended as safe (GRAS) status by the U.S. Federal Drug Administration (USFDA) and include both sugars and sugar alcohols (polyols) which in addition to their technological attributes (sugar replacer, bulking agent, texturiser, humectant, cryoprotectant) have been observed to exert a number of health benefits (low calories, low glycemic index, anticariogenic, osmotic diuretics, obesity control, prebiotic). Some of these sweeteners successfully produced by lactic acid bacteria include mannitol, sorbitol, tagatose, and trehalose and there is a potential to further enhance their production with the help of metabolic engineering. These safe sweeteners can be exploited as vital food ingredients for development of low-calorie foods with added functional values especially for children, diabetic patients, and weight watchers.

  13. Diversity and technological potential of lactic acid bacteria of wheat flours. (United States)

    Alfonzo, Antonio; Ventimiglia, Giusi; Corona, Onofrio; Di Gerlando, Rosalia; Gaglio, Raimondo; Francesca, Nicola; Moschetti, Giancarlo; Settanni, Luca


    Lactic acid bacteria (LAB) were analysed from wheat flours used in traditional bread making throughout Sicily (southern Italy). Plate counts, carried out in three different media commonly used to detect food and sourdough LAB, revealed a maximal LAB concentration of approximately 4.75 Log CFU g(-1). Colonies representing various morphological appearances were isolated and differentiated based on phenotypic characteristics and genetic analysis by randomly amplified polymorphic DNA (RAPD)-PCR. Fifty unique strains were identified. Analysis by 16S rRNA gene sequencing grouped the strains into 11 LAB species, which belonged to six genera: Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus and Weissella. Weissella cibaria, Lactobacillus plantarum, Leuconostoc pseudomesenteroides and Leuconostoc citreum were the most prevalent species. The strains were not geographically related. Denaturing gradient gel electrophoresis (DGGE) analysis of total DNA of flour was used to provide a more complete understanding of the LAB population; it confirmed the presence of species identified with the culture-dependent approach, but did not reveal the presence of any additional LAB species. Finally, the technological characteristics (acidifying capacity, antimicrobial production, proteolytic activity, organic acid, and volatile organic compound generation) of the 50 LAB strains were investigated. Eleven strains were selected for future in situ applications.

  14. Controlled Microwave Heating Accelerates Rolling Circle Amplification. (United States)

    Yoshimura, Takeo; Suzuki, Takamasa; Mineki, Shigeru; Ohuchi, Shokichi


    Rolling circle amplification (RCA) generates single-stranded DNAs or RNA, and the diverse applications of this isothermal technique range from the sensitive detection of nucleic acids to analysis of single nucleotide polymorphisms. Microwave chemistry is widely applied to increase reaction rate as well as product yield and purity. The objectives of the present research were to apply microwave heating to RCA and indicate factors that contribute to the microwave selective heating effect. The microwave reaction temperature was strictly controlled using a microwave applicator optimized for enzymatic-scale reactions. Here, we showed that microwave-assisted RCA reactions catalyzed by either of the four thermostable DNA polymerases were accelerated over 4-folds compared with conventional RCA. Furthermore, the temperatures of the individual buffer components were specifically influenced by microwave heating. We concluded that microwave heating accelerated isothermal RCA of DNA because of the differential heating mechanisms of microwaves on the temperatures of reaction components, although the overall reaction temperatures were the same.

  15. Genotyping of the CCR5 chemokine receptor by isothermal NASBA amplification and differential probe hybridization. (United States)

    Romano, J W; Tetali, S; Lee, E M; Shurtliff, R N; Wang, X P; Pahwa, S; Kaplan, M H; Ginocchio, C C


    The human CCR5 chemokine receptor functions as a coreceptor with CD4 for infection by macrophage-tropic isolates of human immunodeficiency virus type 1 (HIV-1). A mutated CCR5 allele which encodes a protein that does not function as a coreceptor for HIV-1 has been identified. Thus, expression of the wild-type and/or mutation allele is relevant to determining the infectability of patient peripheral blood mononuclear cells (PBMC) and affects disease progression in vivo. We developed a qualitative CCR5 genotyping assay using NASBA, an isothermal nucleic acid amplification technology. The method involves three enzymes and two oligonucleotides and targets the CCR5 mRNA, which is expressed in PBMC at a copy number higher than 2, the number of copies of DNA present encoding the gene. The single oligonucleotide set amplifies both alleles, and genotyping is achieved by separate hybridizations of wild-type- and mutation-specific probes directly to the single-stranded RNA amplification product. Assay sensitivity and specificity were demonstrated with RNAs produced in vitro from plasmid clones bearing the DNA encoding each allele. No detectable cross-reactivity between wild-type and mutation probes was found, and 50 copies of each allele were readily detectable. Analysis of patient samples found that 20% were heterozygous and 1% were homozygous for the CCR5 mutation. Thus, NASBA is a sensitive and specific means of rapidly determining CCR5 genotype and provides several technical advantages over alternative assay systems.

  16. Web technology in the separation of strontium and cesium from INEL-ICPP radioactive acid waste (WM-185)

    Energy Technology Data Exchange (ETDEWEB)

    Bray, L.A.; Brown, G.N.


    Strontium and cesium were successfully removed from radioactive acidic waste (WM-185) at the Idaho National Engineering Laboratory, Idaho Chemical Processing Plant (ICPP), with web technology from 3M and IBC Advanced Technologies, Inc. (IBC). A technical team from Pacific Northwest Laboratory, ICPP, 3M and IBC conducted a very successful series of experiments from August 15 through 18, 1994. The ICPP, Remote Analytical Laboratory, Idaho Falls, Idaho, provided the hot cell facilities and staff to complete these milestone experiments. The actual waste experiments duplicated the initial `cold` simulated waste results and confirmed the selective removal provided by ligand-particle web technology.

  17. Detection of rpoB mutations in rifampin-resistant Mycobacterium tuberculosis by use of rolling circle amplification combined with the DNA chip technology%RCA技术联合DNA芯片检测结核分枝杆菌rpoB基因突变

    Institute of Scientific and Technical Information of China (English)

    张江峰; 张亚丽; 曾照芳


    目的:应用滚环扩增(rolling circle amplification,RCA)技术以DNA芯片为载体建立一种对结核分枝杆菌耐药基因单碱基突变的快速检测方法.方法:根据结核分枝杆菌利福平耐药rpoB基因序列,设计针对该基因常见突变位点的锁式探针,及固定于基因芯片上的捕获探针.针对临床结核分枝杆菌样本的基因组DNA,PCR扩增含有rpoB基因常见突变位点的特异性DNA片段.将与突变型特异性互补结合并环化的锁式探针与芯片上固定的捕获探针进行杂交,并运用滚环扩增技术,将含有生物素标记的dUTP掺入扩增产物,最后通过与亲和素标记的纳米金反应,并银染增强显色.同时与临床样本的测序结果比较.结果:通过优化反应条件,能特异性的检测出结核分枝杆菌耐利福平rpoB基因的单碱基突变,通过对临床样本的检测,结果与测序结果一致.结论:该方法结合了DNA芯片和滚环扩增技术,能够快速有效的检测出耐药结核的单碱基突变,具有高特异性、高灵敏度.%Objective:To establish a method for rapid detection of single base mutations in resistant Myeobacterium tuberculosis by use of rolling circle amplification combined with the DNA chip technology. Methods According to rpoB gene sequence of Myeobacterium tuberculosis rifampicin resistant, padlock probes of the gene mutation types and the capture probe fixed on the gene chip were designed. Amplification of PCR containing rpoB gene mutation types of specific DNA fragments. Padlock probes via connection and cycclization, hybridization with the capture probe fixed on the gene chip. Using rolling circle amplification doped biotin labeled dUTP into the amplification product, finally through with streptavidin labeled gold nanoparticles reaction, and silver enhancement staining, compared with sequencing. Reults By optimizing the reaction conditions, specific detection of Myeobacterium tuberculosis is rifampicin resistant rpo

  18. Spheromak Impedance and Current Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, T K; Hua, D D; Stallard, B W


    It is shown that high current amplification can be achieved only by injecting helicity on the timescale for reconnection, {tau}{sub REC}, which determines the effective impedance of the spheromak. An approximate equation for current amplification is: dI{sub TOR}{sup 2}/dt {approx} I{sup 2}/{tau}{sub REC} - I{sub TOR}{sup 2}/{tau}{sub closed} where I is the gun current, I{sub TOR} is the spheromak toroidal current and {tau}{sub CLOSED} is the ohmic decay time of the spheromak. Achieving high current amplification, I{sub TOR} >> I, requires {tau}{sub REC} <<{tau}{sub CLOSED}. For resistive reconnection, this requires reconnection in a cold zone feeding helicity into a hot zone. Here we propose an impedance model based on these ideas in a form that can be implemented in the Corsica-based helicity transport code. The most important feature of the model is the possibility that {tau}{sub REC} actually increases as the spheromak temperature increases, perhaps accounting for the ''voltage sag'' observed in some experiments, and a tendency toward a constant ratio of field to current, B {proportional_to} I, or I{sub TOR} {approx} I. Program implications are discussed.

  19. Evaluation of application of pooling nucleic acid amplification testing in men who have sex with men population in China%HIV集合核酸检测在男男性行为人群中的应用评价

    Institute of Scientific and Technical Information of China (English)

    江华洲; 沈圣; 裴丽健; 黄晓婕; 吴昊; 闫红梅; 潘品良; 蒋岩


    Objective To evaluate the application of pooling HIV nucleic acid amplification testing (NAAT) among men who had sex with men (MSM) population, and to investigate suitable HIV screening strategy and the feasibility of calculation of HIV incidence using pooling NAAT among MSM population in China.Methods Four thousand eight hundred and fifty-six samples were collected from MSM population from April 2008 to September 2009 among with 4 156 were in Heilongjiang province and 700 were in Beijing in China. After standard testing with an HIV ELISA and WB confirmation testing, HIV antibody-negative samples were pooled and screened for HIV using NAAT.A three-stage pooling strategy was adopted.The HIV positive rate estimated by the four HIV screening strategies was calculated.In addition, 4 156 HIV positive specimens from Heilongjiang province were screened with the BED capture enzyme immunoassay (BED-CEIA).The HIV-1 incidences were estimated by BED-CEIA assay and pooling NAAT individually.ResultsOne hundred and forty-three of 4 856 subjects were HIV infected.130 were 3rd and 4th generation ELISA positive; 13 were antibody-negative but acutely HIV infected.According to the evaluation of four HIV screening strategies, routine HIV screening test together with pooling NAAT was more effective than other strategies for screening out window period generation ELISA+WB+pooling NAAT' were 2.68%(95% confidence interval CI=2.22%-3.14%), 2.82%(95%CI=2.35%-3.29%), 2.94%(95%CI=2.46%-3.42%) and 2.94%(95%CI=2.46%-3.42%), respectively.The differences were not significant (χ2=0.854 3, P=0.836 4).Of the 88 HIV positive samples from Heilongjiang province, 44 participants were tested as recent HIV infections by BED-CEIA assay. The estimated HIV-1 incidence was 2.36% (95%CI=1.63%-3.08%) and 2.92% (95%CI=1.01%-4.83%) based on BED-CEIA assay and pooling NAAT,respectively.Conclusions Pooling NAAT is a effective screening test in HIV negative population to detect window period infection among MSM

  20. Next generation sequencing (NGS)technologies and applications

    Energy Technology Data Exchange (ETDEWEB)

    Vuyisich, Momchilo [Los Alamos National Laboratory


    NGS technology overview: (1) NGS library preparation - Nucleic acids extraction, Sample quality control, RNA conversion to cDNA, Addition of sequencing adapters, Quality control of library; (2) Sequencing - Clonal amplification of library fragments, (except PacBio), Sequencing by synthesis, Data output (reads and quality); and (3) Data analysis - Read mapping, Genome assembly, Gene expression, Operon structure, sRNA discovery, and Epigenetic analyses.

  1. Synthesis of hemicellulose-acrylic acid graft copolymer super water absorbent resin by ultrasonic irradiation technology

    Directory of Open Access Journals (Sweden)

    Fangfang LIU


    Full Text Available The hemicellulose super water absorbent resin is prepared by using ultrasonic irradiation technology, with the waste liquid produced during the preparation of viscose fiber which contains a large amount of hemicellulose as raw material, acrylic acid as graft monomer, N,N’-methylene bis acrylamide (NMBA as cross linking agent, and (NH42S2O8-NaHSO3 as the redox initiation system. The synthesis conditions, structure and water absorption ability of resin are discussed. The results indicate that water absorbency of the resin is 311 g/g, the tap water absorbency is 102 g/g, the normal saline absorbency is 55 g/g, and the artificial urine absorbency is 31 g/g under the optimal synthesis conditions, so the resin has great water absorption rate and water retaining capacity. The FT-IR and SEM analysis shows that the resin with honeycomb network structure is prepared. The successfully synthesized of the resin means that the hemicellulose waste liquid can be highly effectively recycled, and it provides a kind of new raw material for the synthesis of super water absorbent resin.

  2. Final technical report: Commercialization of the Biofine technology for levulinic acid production from paper sludge

    Energy Technology Data Exchange (ETDEWEB)

    Fitzpatrick, Stephen W.


    This project involved a three-year program managed by BioMetics, Inc. (Waltham, MA) to demonstrate the commercial feasibility of Biofine thermochemical process technology for conversion of cellulose-containing wastes or renewable materials into levulinic acid, a versatile platform chemical. The program, commencing in October 1995, involved the design, procurement, construction and operation of a plant utilizing the Biofine process to convert 1 dry ton per day of paper sludge waste. The plant was successfully designed, constructed, and commissioned in 1997. It was operated for a period of one year on paper sludge from a variety of source paper mills to collect data to verify the design for a commercial scale plant. Operational results were obtained for four different feedstock varieties. Stable, continuous operation was achieved for two of the feedstocks. Continuous operation of the plant at demonstration scale provided the opportunity for process optimization, development of operational protocols, operator training and identification of suitable materials of construction for scale up to commercial operation . Separated fiber from municipal waster was also successfully processed. The project team consisted of BioMetics Inc., Great Lakes Chemical Corporation (West Lafayette, IN), and New York State Energy Research and Development Authority (Albany, NY).

  3. Emerging technologies for amino acid nutrition research in the post-genome era. (United States)

    Wang, Junjun; Wu, Guoyao; Zhou, Huaijun; Wang, Fenglai


    Amino acids (AA) are not only the building blocks of proteins but are also key regulators of metabolic pathways in cells. However, the mechanisms responsible for the effects of AA are largely unknown. With the completion of human and other mammalian genome projects, revolutionary technologies in life sciences characterized by high throughput, high efficiency, and rapid computation are now available for AA nutrition research. These advanced tools include genetics (the genomic variety), epigenetics (stable and heritable changes in gene expression or cellular phenotype that occurs without changes in DNA sequence), transcriptomics (alternative mRNA splicing, microRNAs, and gene transcription), proteomics (protein expression and interactions), metabolomics (metabolite profiles in cells and tissues), and bioinformatics (analysis of metabolic pathways using systems biology approach). These robust, powerful methods can be employed for the analysis of DNA, RNA, protein, and low-molecular-weight metabolites, whose expression and concentration are affected by the interaction between genes and dietary AA. With the omics and other advanced methodologies, we expect that the molecular actions of AA on target tissues can be defined and that optimal dietary recommendations for these nutrients can be devised for individual humans (personalized nutrition) and animals (targeted feeding) in response to changes in physiological and pathological conditions.

  4. Lactic acid bacteria from "Sheep's Dhan", a traditional butter: Isolation, identification and major technological traits

    Directory of Open Access Journals (Sweden)


    Full Text Available Twenty six lactic acid bacteria were isolated from sheep’s Dhan, a traditional butter made from sheep’s milk in Jijel (East of Algeria. These strains belong to three genera: Lactococcus, Leuconostoc and Lactobacillus. The results showed that Lactococcus lactis ssp diacetylactis was the predominant species in this traditional butter. The results of the assessment of the technological aptitude indicate that a major strain has a good acidification aptitude, some of them show good proteolytic activity and only Leuconostoc mesenteroides ssp. dextranicum isolates were able to produce exopolysaccharide.

    Veintiséis bacterias lácticas fueron aisladas de “Sheep´s Dhan”, una mantequilla tradicional hecha con leche de oveja en Jijel (al Este de Argelia. Estas cepas pertenecen a tres géneros: Lactococcus, Leuconostoc y Lactobacillus. Los resultados mostraron que Lactococcus lactis ssp diacetylactis fue la especie predominante en esta mantequilla tradicional. Los resultados de la evaluación de la aptitud tecnológica indican que la principal cepa tiene una buena aptitud de acidificación, algunas de ellas mostraron una buena actividad proteolítica y únicamente Leuconostoc mesenteroides ssp. dextranicum fue capaz de producir exopolisacárido.

  5. Parasitic bipolar amplification in a single event transient and its temperature dependence

    Institute of Scientific and Technical Information of China (English)

    Liu Zheng; Chen Shu-Ming; Chen Jian-Jun; Qin Jun-Rui; Liu Rong-Rong


    Using three-dimensional technology computer-aided design (TCAD) simulation,parasitic bipolar amplification in a single event transient (SET) current of a single transistor and its temperature dependence are studied.We quantify the contributions of different current components in a SET current pulse,and it is found that the proportion of parasitic bipolar amplification in total collected charge is about 30% in both 130-nm and 90-nm technologies.The temperature dependence of parasitic bipolar amplification and the mechanism of the SET pulse are also investigated and quantified.The results show that the proportion of charge induced by parasitic bipolar increases with rising temperature,which illustrates that the parasitic bipolar amplification plays an important role in the charge collection of a single transistor.

  6. Simple system for isothermal DNA amplification coupled to lateral flow detection.

    Directory of Open Access Journals (Sweden)

    Kristina Roskos

    Full Text Available Infectious disease diagnosis in point-of-care settings can be greatly improved through integrated, automated nucleic acid testing devices. We have developed an early prototype for a low-cost system which executes isothermal DNA amplification coupled to nucleic acid lateral flow (NALF detection in a mesofluidic cartridge attached to a portable instrument. Fluid handling inside the cartridge is facilitated through one-way passive valves, flexible pouches, and electrolysis-driven pumps, which promotes a compact and inexpensive instrument design. The closed-system disposable prevents workspace amplicon contamination. The cartridge design is based on standard scalable manufacturing techniques such as injection molding. Nucleic acid amplification occurs in a two-layer pouch that enables efficient heat transfer. We have demonstrated as proof of principle the amplification and detection of Mycobacterium tuberculosis (M.tb genomic DNA in the cartridge, using either Loop Mediated Amplification (LAMP or the Exponential Amplification Reaction (EXPAR, both coupled to NALF detection. We envision that a refined version of this cartridge, including upstream sample preparation coupled to amplification and detection, will enable fully-automated sample-in to answer-out infectious disease diagnosis in primary care settings of low-resource countries with high disease burden.

  7. Dynamics and Control of DNA Sequence Amplification

    CERN Document Server

    Marimuthu, Karthikeyan


    DNA amplification is the process of replication of a specified DNA sequence \\emph{in vitro} through time-dependent manipulation of its external environment. A theoretical framework for determination of the optimal dynamic operating conditions of DNA amplification reactions, for any specified amplification objective, is presented based on first-principles biophysical modeling and control theory. Amplification of DNA is formulated as a problem in control theory with optimal solutions that can differ considerably from strategies typically used in practice. Using the Polymerase Chain Reaction (PCR) as an example, sequence-dependent biophysical models for DNA amplification are cast as control systems, wherein the dynamics of the reaction are controlled by a manipulated input variable. Using these control systems, we demonstrate that there exists an optimal temperature cycling strategy for geometric amplification of any DNA sequence and formulate optimal control problems that can be used to derive the optimal tempe...

  8. Dynamics and control of DNA sequence amplification

    Energy Technology Data Exchange (ETDEWEB)

    Marimuthu, Karthikeyan [Department of Chemical Engineering and Center for Advanced Process Decision-Making, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Chakrabarti, Raj, E-mail:, E-mail: [Department of Chemical Engineering and Center for Advanced Process Decision-Making, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Division of Fundamental Research, PMC Advanced Technology, Mount Laurel, New Jersey 08054 (United States)


    DNA amplification is the process of replication of a specified DNA sequence in vitro through time-dependent manipulation of its external environment. A theoretical framework for determination of the optimal dynamic operating conditions of DNA amplification reactions, for any specified amplification objective, is presented based on first-principles biophysical modeling and control theory. Amplification of DNA is formulated as a problem in control theory with optimal solutions that can differ considerably from strategies typically used in practice. Using the Polymerase Chain Reaction as an example, sequence-dependent biophysical models for DNA amplification are cast as control systems, wherein the dynamics of the reaction are controlled by a manipulated input variable. Using these control systems, we demonstrate that there exists an optimal temperature cycling strategy for geometric amplification of any DNA sequence and formulate optimal control problems that can be used to derive the optimal temperature profile. Strategies for the optimal synthesis of the DNA amplification control trajectory are proposed. Analogous methods can be used to formulate control problems for more advanced amplification objectives corresponding to the design of new types of DNA amplification reactions.


    Directory of Open Access Journals (Sweden)

    Rozália Veronika Salamon


    Full Text Available The fatty acid composition of cow’s milk with fat contents of 3.6%, Dalia cheese with fat contents of 44%, butter with fat contents of 80% and margarine with fat contents of 24% was determined after a heat treatment performed on cooking plate and microwave treatment, respectively of different durations. The biggest difference was obtained for oleic acid and elaidic acid since, with the exception of the margarine, in each case proportion of the cis-configurated oleic acid decreased while that of the trans-configurated elaidic acid increased. For all of the other fatty acids in the foodstuffs examined no such differences were obtained regarding change in fatty acid composition whose differences could influence healthy nutrition to considerable extent. Therefore we can take it as a fact that neither heat treatment performed on a traditional cooking plate nor microwave treatment affects considerably the composition of food fats.

  10. Chirality Amplification in Tactoids of Lyotropic Chromonic Liquid Crystals (United States)

    Peng, Chenhui; Lavrentovich, Oleg


    We demonstrate an effective chirality amplification based on the long-range forces, extending over the scales of tens of micrometers, much larger than the single molecule (nanometer) scale. The mechanism is rooted in the long-range elastic nature of orientational order in lyotropic chromonic liquid crystals (LCLCs) that represent water solutions of achiral disc-like molecules. Minute quantities of chiral molecules such as amino acid L-alanine and limonene added to the droplets of LCLC lead to chiral amplification characterized by an increase of optical activity by a factor of 103 - 104. This effect allows one to discriminate and detect the absolute configuration of chiral molecules in an aqueous system, thus opening new possibilities in biosensing and other biological applications.

  11. Clostridium difficile testing algorithms using glutamate dehydrogenase antigen and C. difficile toxin enzyme immunoassays with C. difficile nucleic acid amplification testing increase diagnostic yield in a tertiary pediatric population. (United States)

    Ota, Kaede V; McGowan, Karin L


    We evaluated the performance of the rapid C. diff Quik Chek Complete's glutamate dehydrogenase antigen (GDH) and toxin A/B (CDT) tests in two algorithmic approaches for a tertiary pediatric population: algorithm 1 entailed initial testing with GDH/CDT followed by loop-mediated isothermal amplification (LAMP), and algorithm 2 entailed GDH/CDT followed by cytotoxicity neutralization assay (CCNA) for adjudication of discrepant GDH-positive/CDT-negative results. A true positive (TP) was defined as positivity by CCNA or positivity by LAMP plus another test (GDH, CDT, or the Premier C. difficile toxin A and B enzyme immunoassay [P-EIA]). A total of 141 specimens from 141 patients yielded 27 TPs and 19% prevalence. Sensitivity, specificity, positive predictive value, and negative predictive value were 56%, 100%, 100%, and 90% for P-EIA and 81%, 100%, 100%, and 96% for both algorithm 1 and algorithm 2. In summary, GDH-based algorithms detected C. difficile infections with superior sensitivity compared to P-EIA. The algorithms allowed immediate reporting of half of all TPs, but LAMP or CCNA was required to confirm the presence or absence of toxigenic C. difficile in GDH-positive/CDT-negative specimens.

  12. Phenotypic and technological diversity of lactic acid bacteria and staphylococci isolated from traditionally fermented sausages in southern Greece. (United States)

    Drosinos, Eleftherios H; Paramithiotis, Spiros; Kolovos, George; Tsikouras, Ioannis; Metaxopoulos, Ioannis


    The physicochemical and microbiological characteristics of spontaneously fermented sausages made by two medium-sized enterprises (MSE) located in southern Greece have been studied. A total of 300 lactic acid bacteria and 300 staphylococcal strains have been isolated and identified by their physiological characteristics. Lactobacillus plantarum strains were found to dominate the lactic acid bacteria microbiota in most of the cases with L. sakei strains prevailing in some of them and L. rhamnosus strains occasionally accompanying the dominant lactic acid bacteria microbiota. On the other hand, S. saprophyticus strains were found to dominate the staphylococcal microbiota in all spontaneously fermented sausages with of S. simulans, S. xylosus, S. gallinarum and S. cohnii cohnii strains being sporadically present. Following the identification, an evaluation of their technological properties, namely proteolytic and lipolytic capacities as well as production of biogenic amines and antimicrobial compounds, took place. None of the lactic acid bacteria and staphylococci was found to possess lipolytic activity whereas a total of 6 lactic acid bacteria and 51 staphylococci strains were found to be able to hydrolyse either the sarcoplasic, myofibrillar or both protein fractions. Furthermore, only one L. sakei strain and 185 staphylococci strains were found to possess decarboxylase activity against lysine, tyrosine, ornithine or histidine. Finally none of the staphylococcal microbiota and 3 lactic acid bacteria strains were found to be able to produce antimicrobial compounds of proteinaceous nature against Listeria monocytogenes.

  13. LAMP (Loop-mediated isothermal amplification of DNA) - A technique for biotype discrimination in Bemisia tabaci (United States)

    Loop-mediated isothermal amplification of DNA (LAMP) can amplify a target DNA sequence at a constant temperature in about 1 hour. LAMP technology has great potential for agricultural applications because of the need for rapid and inexpensive diagnoses. Assays based on LAMP technology are well suited...

  14. Role of modifier in microwave assisted extraction of oleanolic acid from Gymnema sylvestre: application of green extraction technology for botanicals. (United States)

    Mandal, Vivekananda; Dewanjee, Saikat; Mandal, Subhash C


    This work highlights the development of a green extraction technology for botanicals with the use of microwave energy. Taking into consideration the extensive time involved in conventional extraction methods, coupled with usage of large volumes of organic solvent and energy resources, an ecofriendly green method that can overcome the above problems has been developed. The work compares the effect of sample pretreatment with untreated sample for improved yield of oleanolic acid from Gymnema sylvestre leaves. The pretreated sample with water produced 0.71% w/w oleanolic acid in one extraction cycle with 500 W microwave power, 25 mL methanol and only an 8 min extraction time. On the other hand, a conventional heat reflux extraction for 6 hours could produce only 0.62% w/w oleanolic acid. The detailed mechanism of extraction has been studied through scanning electron micrographs. The environmental impact of the proposed green method has also been evaluated.

  15. An evaluation of multiple annealing and looping based genome amplification using a synthetic bacterial community

    Institute of Scientific and Technical Information of China (English)

    WANG Yong; GAO Zhaoming; XU Ying; LI Guangyu; HE Lisheng; QIAN Peiyuan


    The low biomass in environmental samples is a major challenge for microbial metagenomic studies. The amplification of a genomic DNA was frequently applied to meeting the minimum requirement of the DNA for a high-throughput next-generation-sequencing technology. Using a synthetic bacterial community, the amplification efficiency of the Multiple Annealing and Looping Based Amplification Cycles (MALBAC) kit that is originally developed to amplify the single-cell genomic DNA of mammalian organisms is examined. The DNA template of 10 pg in each reaction of the MALBAC amplification may generate enough DNA for Illumina sequencing. Using 10 pg and 100 pg templates for each reaction set, the MALBAC kit shows a stable and homogeneous amplification as indicated by the highly consistent coverage of the reads from the two amplified samples on the contigs assembled by the original unamplified sample. Although GenomePlex whole genome amplification kit allows one to generate enough DNA using 100 pg of template in each reaction, the minority of the mixed bacterial species is not linearly amplified. For both of the kits, the GC-rich regions of the genomic DNA are not efficiently amplified as suggested by the low coverage of the contigs with the high GC content. The high efficiency of the MALBAC kit is supported for the amplification of environmental microbial DNA samples, and the concerns on its application are also raised to bacterial species with the high GC content.

  16. By-Product Formation in Repetitive PCR Amplification of DNA Libraries during SELEX

    DEFF Research Database (Denmark)

    Tolle, Fabian; Wilke, Julian; Wengel, Jesper


    The selection of nucleic acid aptamers is an increasingly important approach to generate specific ligands binding to virtually any molecule of choice. However, selection-inherent amplification procedures are prone to artificial by-product formation that prohibits the enrichment of target-recogniz......The selection of nucleic acid aptamers is an increasingly important approach to generate specific ligands binding to virtually any molecule of choice. However, selection-inherent amplification procedures are prone to artificial by-product formation that prohibits the enrichment of target......-recognizing aptamers. Little is known about the formation of such by-products when employing nucleic acid libraries as templates. We report on the formation of two different forms of by-products, named ladder- and non-ladder-type observed during repetitive amplification in the course of in vitro selection experiments...

  17. Nitrogen dioxide reducing ascorbic acid technologies in the ventilator circuit leads to uniform NO concentration during inspiration. (United States)

    Pezone, Matthew J; Wakim, Matthew G; Denton, Ryan J; Gamero, Lucas G; Roscigno, Robert F; Gilbert, Richard J; Lovich, Mark A


    Conventional inhaled NO systems deliver NO by synchronized injection or continuous NO flow in the ventilator circuitry. Such methods can lead to variable concentrations during inspiration that may differ from desired dosing. NO concentrations in these systems are generally monitored through electrochemical methods that are too slow to capture this nuance and potential dosing error. A novel technology that reduces NO2 into NO via low-resistance ascorbic-acid cartridges just prior to inhalation has recently been described. The gas volume of these cartridges may enhance gas mixing and reduce dosing inconsistency throughout inhalation. The impact of the ascorbic-acid cartridge technology on NO concentration during inspiration was characterized through rapid chemiluminescence detection during volume control ventilation, pressure control ventilation, synchronized intermittent mandatory ventilation and continuous positive airway pressure using an in vitro lung model configured to simulate the complete uptake of NO. Two ascorbic acid cartridges in series provided uniform and consistent dosing during inspiration during all modes of ventilation. The use of one cartridge showed variable inspiratory concentration of NO at the largest tidal volumes, whereas the use of no ascorbic acid cartridge led to highly inconsistent NO inspiratory waveforms. The use of ascorbic acid cartridges also decreased breath-to-breath variation in SIMV and CPAP ventilation. The ascorbic-acid cartridges, which are designed to convert NO2 (either as substrate or resulting from NO oxidation during injection) into NO, also provide the benefit of minimizing the variation of inhaled NO concentration during inspiration. It is expected that the implementation of this method will lead to more consistent and predictable dosing.

  18. Multiscale image contrast amplification (MUSICA) (United States)

    Vuylsteke, Pieter; Schoeters, Emile P.


    This article presents a novel approach to the problem of detail contrast enhancement, based on multiresolution representation of the original image. The image is decomposed into a weighted sum of smooth, localized, 2D basis functions at multiple scales. Each transform coefficient represents the amount of local detail at some specific scale and at a specific position in the image. Detail contrast is enhanced by non-linear amplification of the transform coefficients. An inverse transform is then applied to the modified coefficients. This yields a uniformly contrast- enhanced image without artefacts. The MUSICA-algorithm is being applied routinely to computed radiography images of chest, skull, spine, shoulder, pelvis, extremities, and abdomen examinations, with excellent acceptance. It is useful for a wide range of applications in the medical, graphical, and industrial area.

  19. Amplification of cellular oncogenes in solid tumors

    Directory of Open Access Journals (Sweden)

    Ozkan Bagci


    Full Text Available The term gene amplification refers to an increase in copy number of a gene. Upregulation of gene expression through amplification is a general mechanism to increase gene dosage. Oncogene amplifications have been shown in solid human cancers and they are often associated with progression of cancer. Defining oncogene amplification is useful since it is used as a prognostic marker in clinical oncology nowadays, especially v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2 (HER2 targeted agents are used in breast cancer patients with high level of HER2 overexpression as a therapeutic approach. However, patients without HER2 overexpression do not appear to benefit from these agents. We concluded that determination of oncogene amplification in solid tumors is an important factor in treatment of human cancers with many unknowns. We have referred to PubMed and some databases to prepare this article.

  20. Application of organic acid Composite Blockage Removal Technology%低碳复合有机酸解堵技术

    Institute of Scientific and Technical Information of China (English)

    陈锐; 余海棠


    义正油田长6油层酸敏性强,矿物中的高岭石和绿泥石含量较高,不宜采用常规酸化解堵措施。该区油层伤害以敏感性伤害、措施及开采过程中的有机、无机物堵塞为主。低碳复合有机酸主要有缓速酸、有机溶剂、氧化剂等组成,依靠缓释酸的溶蚀性,有机溶剂的溶解性及其它成分的协同作用,达到解堵的目的。室内评价结果表明,低碳复合有机酸可以有效解除油井的高分子聚合物、无机垢的堵塞。在合理选井的基础上,将其应用于现场,取得了良好的效果。%Yizheng oilfield C6 oil reservoir is acid sensitivity,and the main reservoir minerals of C6 oil reservoir are kaolinite and chlorite,thus,the conventional acidizing blockage removal technology is not suitable for C6 oil reservoir. Reservoir damage is mainly sensibility damage,pluged by organic and inorganic matter produced by stimulation and exploitation process in this area. Co-organic acid is mainly compose of retarded acid,organic solvent,oxidant,etc. Depending on dissolution by slowly releasing acids,solubility in organic solvents and synergism of other components to achieve the goal of blockage removal.The test indoor results showed that organic acid composite blockage removal technology can remove blockage produced by high molecule polymer,inorganic scale effectively.The organic acid composite blockage removal technology has been applied to the scene to remove the reservoir blockage successfully and it has made a good effect on the basis of selecting oil well correctly.

  1. Characterization of Humic Acid in the Chemical Oxidation Technology (II) - Characteristics by Ozonation -

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.S.; Jung, Y.R. [Kangwon National University, Chunchon (Korea)


    In this paper, ozonation of humic acid in water was characterized using UV{sub 254} absorbance, TOC, Ultra Filtration and {sup 13}C-NMR. Also, carbonyl compounds in ozonated water were analyzed by GC/MS using PFBOA method. Ozonation by-products of water containing humic acid were determined as formaldehyde, acetaldehyde, acetone, glyoxal and methylglyoxal. Results of UV{sub 254} absorbance and TOC with ozonation time at humic acid 20, 100 ppm represent that decrease rate of 80% within ozonation time is 20 min and TOC removal rate of 40-50% within ozonation time is 30 min. Results for {sup 13}C-NMR and Ultra Filtration, humic acid of high molecular weight by ozonation are oxidated and decomposed so that it was conversed low molecular weight such as aldehydes, carboxylic acid. (author). 7 refs., 3 tabs., 9 figs.

  2. Pulse Compression And Raman Amplification In Optical Fibres (United States)

    Byron, Kevin C.


    Experimental and theoretical investigations on Raman amplification in fibres have been carried out and simultaneous amplification and pulse compression observed. With a fibre design optimised for amplification high gain may be obtained at practical pump power levels.

  3. The effect of acid hydrolysis on the technological functional properties of pinhão (Araucaria brasiliensis starch

    Directory of Open Access Journals (Sweden)

    Roberta Cruz Silveira Thys


    Full Text Available Technological functional properties of native and acid-thinned pinhão (seeds of Araucária angustifolia, Brazilian pine starches were evaluated and compared to those of native and acid-thinned corn starches. The starches were hydrolyzed (3.2 mol.L-1 HCl, 44 ºC, 6 hours and evaluated before and after the hydrolysis reaction in terms of formation, melting point and thermo-reversibility of gel starches, retrogradation (in a 30-day period and measurements every three days, paste freezing and thawing stability (after six freezing and thawing cycles, swelling power, and solubility. The results of light transmittance (% of pastes of native and acid-thinned pinhão starches was higher (lower tendency to retrogradation than that obtained for corn starches after similar storage period. Native pinhão starch (NPS presented lower syneresis than native corn starch (NCS when submitted to freeze-thaw cycles. The acid hydrolysis increased the syneresis of the two native varieties under storage at 5 ºC and after freezing and thawing cycles. The solubility of NPS was lower than that of native corn starch at 25, 50, and 70 ºC. However, for the acid-thinned pinhão starch (APS, this property was significantly higher (p < 0.05 when compared to that of acid-thinned corn starch (ACS. From the results obtained, it can be said that the acid treatment was efficient in producing a potential fat substitute from pinhão starch variety, but this ability must be further investigated.

  4. A new unnatural base pair system between fluorophore and quencher base analogues for nucleic acid-based imaging technology. (United States)

    Kimoto, Michiko; Mitsui, Tsuneo; Yamashige, Rie; Sato, Akira; Yokoyama, Shigeyuki; Hirao, Ichiro


    In the development of orthogonal extra base pairs for expanding the genetic alphabet, we created novel, unnatural base pairs between fluorophore and quencher nucleobase analogues. We found that the nucleobase analogue, 2-nitropyrrole (denoted by Pn), and its 4-substitutions, such as 2-nitro-4-propynylpyrrole (Px) and 4-[3-(6-aminohexanamido)-1-propynyl]-2-nitropyrrole (NH(2)-hx-Px), act as fluorescence quenchers. The Pn and Px bases specifically pair with their pairing partner, 7-(2,2'-bithien-5-yl)imidazo[4,5-b]pyridine (Dss), which is strongly fluorescent. Thus, these unnatural Dss-Pn and Dss-Px base pairs function as reporter-quencher base pairs, and are complementarily incorporated into DNA by polymerase reactions as a third base pair in combination with the natural A-T and G-C pairs. Due to the static contact quenching, the Pn and Px quencher bases significantly decreased the fluorescence intensity of Dss by the unnatural base pairings in DNA duplexes. In addition, the Dss-Px pair exhibited high efficiency and selectivity in PCR amplification. Thus, this new unnatural base pair system would be suitable for detection methods of target nucleic acid sequences, and here we demonstrated the applications of the Dss-Pn and Dss-Px pairs as molecular beacons and in real-time PCR. The genetic alphabet expansion system with the replicable, unnatural fluorophore-quencher base pair will be a useful tool for sensing and diagnostic applications, as well as an imaging tool for basic research.

  5. Ancient DNA: genomic amplification of Roman and medieval bovine bones

    Directory of Open Access Journals (Sweden)

    A. Valentini


    Full Text Available Cattle remains (bones and teeth of both roman and medieval age were collected in the archaeological site of Ferento (Viterbo, Italy with the aim of extracting and characterising nucleic acids. Procedures to minimize contamination with modern DNA and to help ancient DNA (aDNA preservation of the archaeological remains were adopted. Different techniques to extract aDNA (like Phenol/chloroform extraction from bovine bones were tested to identify the method that applies to the peculiar characteristics of the study site. Currently, aDNA investigation is mainly based on mtDNA, due to the ease of amplification of the small and high-copied genome and to its usefulness in evolutionary studies. Preliminary amplification of both mitochondrial and nuclear aDNA fragments from samples of Roman and medieval animals were performed and partial specific sequences of mitochondrial D-loop as well as of nuclear genes were obtained. The innovative amplification of nuclear aDNA could enable the analysis of genes involved in specific animal traits, giving insights of ancient economic and cultural uses, as well as providing information on the origin of modern livestock population.

  6. Linking Arctic amplification and local feedbacks (United States)

    Balcerak, Ernie


    Climate simulations show that as the Earth warms, the Arctic warms more than the average global warming. However, models differ on how much more the Arctic warms, and although scientists have proposed a variety of mechanisms to explain the Arctic warming amplification, there is no consensus on the main reasons for it. To shed light on this issue, Hwang et al. investigated the relationship between Arctic amplification and poleward energy transport and local Arctic feedbacks, such as changes in cloud cover or ice loss, across a group of models. The researchers noted that differences in atmospheric energy transport did not explain the ranges of polar amplification; rather, models with more amplification showed less energy transport into high latitudes. The authors found that decreasing energy transport is due to a coupled relationship between Arctic amplification and energy transport: Arctic amplification reduces the equator-to-pole temperature gradient, which strongly decreases energy transport. They suggest that this coupled relationship should be taken into account in studies of Arctic amplification. (Geophysical Research Letters, doi:10.1029/2011GL048546, 2011)

  7. Quantum Amplitude Amplification and Estimation

    CERN Document Server

    Brassard, G; Mosca, M; Tapp, A; Brassard, Gilles; Hoyer, Peter; Mosca, Michele; Tapp, Alain


    Consider a Boolean function $\\chi: X \\to \\{0,1\\}$ that partitions set $X$ between its good and bad elements, where $x$ is good if $\\chi(x)=1$ and bad otherwise. Consider also a quantum algorithm $\\mathcal A$ such that $A \\ket{0} = \\sum_{x\\in X} \\alpha_x \\ket{x}$ is a quantum superposition of the elements of $X$, and let $a$ denote the probability that a good element is produced if $A \\ket{0}$ is measured. If we repeat the process of running $A$, measuring the output, and using $\\chi$ to check the validity of the result, we shall expect to repeat $1/a$ times on the average before a solution is found. *Amplitude amplification* is a process that allows to find a good $x$ after an expected number of applications of $A$ and its inverse which is proportional to $1/\\sqrt{a}$, assuming algorithm $A$ makes no measurements. This is a generalization of Grover's searching algorithm in which $A$ was restricted to producing an equal superposition of all members of $X$ and we had a promise that a single $x$ existed such tha...

  8. GMO detection using a bioluminescent real time reporter (BART of loop mediated isothermal amplification (LAMP suitable for field use

    Directory of Open Access Journals (Sweden)

    Kiddle Guy


    Full Text Available Abstract Background There is an increasing need for quantitative technologies suitable for molecular detection in a variety of settings for applications including food traceability and monitoring of genetically modified (GM crops and their products through the food processing chain. Conventional molecular diagnostics utilising real-time polymerase chain reaction (RT-PCR and fluorescence-based determination of amplification require temperature cycling and relatively complex optics. In contrast, isothermal amplification coupled to a bioluminescent output produced in real-time (BART occurs at a constant temperature and only requires a simple light detection and integration device. Results Loop mediated isothermal amplification (LAMP shows robustness to sample-derived inhibitors. Here we show the applicability of coupled LAMP and BART reactions (LAMP-BART for determination of genetically modified (GM maize target DNA at low levels of contamination (0.1-5.0% GM using certified reference material, and compare this to RT-PCR. Results show that conventional DNA extraction methods developed for PCR may not be optimal for LAMP-BART quantification. Additionally, we demonstrate that LAMP is more tolerant to plant sample-derived inhibitors, and show this can be exploited to develop rapid extraction techniques suitable for simple field-based qualitative tests for GM status determination. We also assess the effect of total DNA assay load on LAMP-BART quantitation. Conclusions LAMP-BART is an effective and sensitive technique for GM detection with significant potential for quantification even at low levels of contamination and in samples derived from crops such as maize with a large genome size. The resilience of LAMP-BART to acidic polysaccharides makes it well suited to rapid sample preparation techniques and hence to both high throughput laboratory settings and to portable GM detection applications. The impact of the plant sample matrix and genome loading

  9. 松萝酸制备工艺的研究%Reserch the Preparatory Technology of Usnic Acid

    Institute of Scientific and Technical Information of China (English)

    肖旭平; 周莉


    目的:探讨松萝酸提取工艺新方法及进行检测鉴定.方法:采用热乙醇回流提取法,离心分离得到松萝酸、蒸发皿蒸干,收集后为纯品.用紫外UV-2204型光谱仪、熔点测定仪进行定性分析,用高效液相色谱仪对纯度进行测定.结果:从植物松萝中提取松萝酸纯度达到99.87%,熔点、紫外吸收光谱分析与标准品相一致.结论:该提取工艺简单,成本低,适合规模化生产,对环境无污染,有利于松萝酸的开发利用.%Objective :Porbe into a new technological method of abstract Usnic Acid and analysis and identification method.Method:Use an abstract method by heat Alcohol regurgitation, make centrifugation and separation to gain Usnic Acid,then evaporate by an evaporating dish ,form the pure quality ,use an UV -2204 type ultraviolate spectrometer and a king of fusion - pointmeter to make the qualitive analysis and measure the purified quality by a liquid phase Chromatograph.Result: Usnea could achieve 99.87% ,fusion point and ultravionlat absorption spectrum analysis agree to the standard samples.Conclusion:this abstracted technological scale.Conclusion:This abstracted technological method is very simple,its cost is low, suits to bigger scale production, no environment pollution, profits to develpoe and use Usnic Acid.

  10. Experiments Study on Charge Technology of Lead-Acid Electric Vehicle Batteries

    Institute of Scientific and Technical Information of China (English)

    LI Wen; ZHANG Cheng-ning


    The basic theory of the fast charge and several charge methods are introduced. In order to heighten charge efficiency of valve-regulated lead-acid battery and shorten the charge time, five charge methods are investigated with experiments done on the Digatron BNT 400-050 test bench. Battery current, terminal voltage, capacity, energy and terminal pole temperature during battery experiment were recorded, and corresponding curves were depicted. Battery capacity-time ratio, energy efficiency and energy-temperature ratio are put forward to be the appraising criteria of lead-acid battery on electric vehicle (EV). According to the appraising criteria and the battery curves, multistage-current/negative-pulse charge method is recommended to charge lead-acid EV battery.

  11. Raman amplification in optical communication systems

    DEFF Research Database (Denmark)

    Kjær, Rasmus


    Fiber Raman amplifiers are investigated with the purpose of identifying new applications and limitations for their use in optical communication systems. Three main topics are investigated, namely: New applications of dispersion compensating Raman amplifiers, the use Raman amplification to increase...

  12. Can Anomalous Amplification be Attained Without Postselection?

    CERN Document Server

    Martínez-Rincón, Julián; Viza, Gerardo I; Howell, John C


    We present a parameter estimation technique based on performing joint measurements of a weak interaction away from the weak-value-amplification approximation. Two detectors are used to collect full statistics of the correlations between two weakly entangled degrees of freedom. Without the need of postselection, the protocol resembles the anomalous amplification of an imaginary-weak-value-like response. The amplification is induced in the difference signal of both detectors allowing robustness to different sources of technical noise, and offering in addition the advantages of balanced signals for precision metrology. All of the Fisher information about the parameter of interest is collected, and a phase controls the amplification response. We experimentally demonstrate the proposed technique by measuring polarization rotations in a linearly polarized laser pulse. The effective sensitivity and precision of a split detector is increased when compared to a conventional continuous-wave balanced detection technique...

  13. Theoretical principles of in vitro selection using combinatorial nucleic acid libraries. (United States)

    Vant-Hull, B; Gold, L; Zichi, D A


    A new paradigm for drug discovery and biological research has developed from technologies that integrate combinatorial chemistry with rounds of selection and amplification, a technique called in vitro selection or systematic evolution of ligands by exponential enrichment (SELEX). This overview unit discusses nucleic acid libraries that can be used, affinity probability distributions, an equilibrium model for SELEX, and optimal conditions including concentrations and signal-to-noise ratios.

  14. The predictive power of synthetic nucleic acid technologies in RNA biology. (United States)

    Chakraborty, Saikat; Mehtab, Shabana; Krishnan, Yamuna


    CONSPECTUS: The impact of nucleic acid nanotechnology in terms of transforming motifs from biology in synthetic and translational ways is widely appreciated. But it is also emerging that the thinking and vision behind nucleic acids as construction material has broader implications, not just in nanotechnology or even synthetic biology, but can feed back into our understanding of biology itself. Physicists have treated nucleic acids as polymers and connected physical principles to biology by abstracting out the molecular interactions. In contrast, biologists delineate molecular players and pathways related to nucleic acids and how they may be networked. But in vitro nucleic acid nanotechnology has provided a valuable framework for nucleic acids by connecting its biomolecular interactions with its materials properties and thereby superarchitecture ultramanipulation that on multiple occasions has pre-empted the elucidation of how living cells themselves are exploiting these same structural concepts. This Account seeks to showcase the larger implications of certain architectural principles that have arisen from the field of structural DNA/RNA nanotechnology in biology. Here we draw connections between these principles and particular molecular phenomena within living systems that have fed in to our understanding of how the cell uses nucleic acids as construction material to achieve different functions. We illustrate this by considering a few exciting and emerging examples in biology in the context of both switchable systems and scaffolding type systems. Due to the scope of this Account, we will focus our discussion on examples of the RNA scaffold as summarized. In the context of switchable RNA architectures, the synthetic demonstration of small molecules blocking RNA translation preceded the discovery of riboswitches. In another example, it was after the description of aptazymes that the first allosteric ribozyme, glmS, was discovered. In the context of RNA architectures

  15. Rolling circle amplification of metazoan mitochondrialgenomes

    Energy Technology Data Exchange (ETDEWEB)

    Simison, W. Brian; Lindberg, D.R.; Boore, J.L.


    Here we report the successful use of rolling circle amplification (RCA) for the amplification of complete metazoan mt genomes to make a product that is amenable to high-throughput genome sequencing techniques. The benefits of RCA over PCR are many and with further development and refinement of RCA, the sequencing of organellar genomics will require far less time and effort than current long PCR approaches.

  16. Using electromagnetic induction technology to predict volatile fatty acid, source area differences (United States)

    Subsurface sampling techniques have been adapted to measure manure accumulation on feedlot surface. Objectives of this study were to determine if sensor data could be used to predict differences in volatile fatty acids (VFA) and other volatiles produced on the feedlot surface three days following a...

  17. Clean coal technology and acid rain compliance: An examination of alternative incentive proposals

    Energy Technology Data Exchange (ETDEWEB)

    McDermott, K.A. [Center for Regulatory Studies, Normal, IL (United States); South, D.W. [Argonne National Lab., IL (United States)


    The Clean Air Act Amendments (CAAA) of 1990 rely primarily on the use of market incentives to stimulate least-cost compliance choices by electric utilities. Because of the potential risks associated with selecting Clean Coal Technologies (CCTs) and the public-good nature of technology commercialization, electric utilities may be reluctant to adopt CCTs as part of their compliance strategies. This paper examines the nature of the risks and perceived impediments to adopting CCTs as a compliance option. It also discusses the incentives that regulatory policy makers could adopt to mitigate these barriers to CCT adoption. (VC)

  18. Clean coal technology and acid rain compliance: An examination of alternative incentive proposals

    Energy Technology Data Exchange (ETDEWEB)

    McDermott, K.A. (Center for Regulatory Studies, Normal, IL (United States)); South, D.W. (Argonne National Lab., IL (United States))


    The Clean Air Act Amendments (CAAA) of 1990 rely primarily on the use of market incentives to stimulate least-cost compliance choices by electric utilities. Because of the potential risks associated with selecting Clean Coal Technologies (CCTs) and the public-good nature of technology commercialization, electric utilities may be reluctant to adopt CCTs as part of their compliance strategies. This paper examines the nature of the risks and perceived impediments to adopting CCTs as a compliance option. It also discusses the incentives that regulatory policy makers could adopt to mitigate these barriers to CCT adoption. (VC)

  19. Water recycling from mixed chromic acid waste effluents by membrane technology

    NARCIS (Netherlands)

    Frenzel, I.; Stamatialis, D.F.; Wessling, M.


    Approaching zero discharge waste on site requires economical treatment technologies for the plating industry, recovering high quality rinse water for reuse. The combination of membranes and evaporation could be an efficient way to downsize the cost and the energy intensive evaporation equipment. In

  20. Amplification of RNA by NASBA allows direct detection of viable cells of Ralstonia solanacearum in potato

    NARCIS (Netherlands)

    Bentsink, L.; Leone, G.O.M.; Beckhoven, van J.R.C.M.; Schijndel, van H.B.; Gemen, van B.; Wolf, van der J.M.


    Aims: The objective of this study was to develop a Nucleic Acid Sequence Based Amplification (NASBA) assay, targeting 16S rRNA sequences, for direct detection of viable cells of Ralstonia solanacearum, the causal organism of bacterial wilt. The presence of intact 16S rRNA is considered to be a usefu

  1. Heat induces gene amplification in cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Bin, E-mail: [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS 39213 (United States); Mercy Cancer Center, Mercy Medical Center-North Iowa, Mason City, IA 50401 (United States); Ouyang, Ruoyun [Department of Respiratory Medicine, The Second Xiangya Hospital, Xinagya School of Medicine, Central South University, Changsha 410011 (China); Huang, Chenghui [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS 39213 (United States); Department of Oncology, The Third Xiangya Hospital, Xinagya School of Medicine, Central South University, Changsha 410013 (China); Liu, Franklin [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States); Neill, Daniel [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS 39213 (United States); Li, Chuanyuan [Dermatology, Duke University Medical Center, Durham, NC 27710 (United States); Dewhirst, Mark [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States)


    Highlights: Black-Right-Pointing-Pointer This study discovered that heat exposure (hyperthermia) results in gene amplification in cancer cells. Black-Right-Pointing-Pointer Hyperthermia induces DNA double strand breaks. Black-Right-Pointing-Pointer DNA double strand breaks are considered to be required for the initiation of gene amplification. Black-Right-Pointing-Pointer The underlying mechanism of heat-induced gene amplification is generation of DNA double strand breaks. -- Abstract: Background: Hyperthermia plays an important role in cancer therapy. However, as with radiation, it can cause DNA damage and therefore genetic instability. We studied whether hyperthermia can induce gene amplification in cancer cells and explored potential underlying molecular mechanisms. Materials and methods: (1) Hyperthermia: HCT116 colon cancer cells received water-submerged heating treatment at 42 or 44 Degree-Sign C for 30 min; (2) gene amplification assay using N-(phosphoacetyl)-L-aspartate (PALA) selection of cabamyl-P-synthetase, aspartate transcarbarmylase, dihydro-orotase (cad) gene amplified cells; (3) southern blotting for confirmation of increased cad gene copies in PALA-resistant cells; (4) {gamma}H2AX immunostaining to detect {gamma}H2AX foci as an indication for DNA double strand breaks. Results: (1) Heat exposure at 42 or 44 Degree-Sign C for 30 min induces gene amplification. The frequency of cad gene amplification increased by 2.8 and 6.5 folds respectively; (2) heat exposure at both 42 and 44 Degree-Sign C for 30 min induces DNA double strand breaks in HCT116 cells as shown by {gamma}H2AX immunostaining. Conclusion: This study shows that heat exposure can induce gene amplification in cancer cells, likely through the generation of DNA double strand breaks, which are believed to be required for the initiation of gene amplification. This process may be promoted by heat when cellular proteins that are responsible for checkpoints, DNA replication, DNA repair and

  2. Technology. (United States)

    Online-Offline, 1998


    Focuses on technology, on advances in such areas as aeronautics, electronics, physics, the space sciences, as well as computers and the attendant progress in medicine, robotics, and artificial intelligence. Describes educational resources for elementary and middle school students, including Web sites, CD-ROMs and software, videotapes, books,…

  3. Technology and kinetics of free fatty acids esterification in tung oil

    Institute of Scientific and Technical Information of China (English)

    GAN Meng-yu; PAN Deng; LI Xiao-mei; HE Ling; CHEN Qi


    We studied the esterificatien of free fatty acids (FFA) in tung oil with methanol by using activated carbon treated with sulfuric acid as a catalyst, and investigated the effect of different temperatures, methanol/oil mole ratio and catalyst amount on the conversion of FFA. Results show that the optimal reaction condition is when the reaction time is 2 h, the mass fraction of the catalyst to total material is 5%, the molar ratio of menthol to FFA is 15 : 1, and the reaction temperature is 368.15 K. We also investigated the kinetics of esterification at various temperatures. Results indicate that the rate-control step could be attributed to the surface reaction, and within the range of the experimental conditions, the as-calculated kinetics formula can depict the esterification processes well.

  4. Non-instrumented incubation of a recombinase polymerase amplification assay for the rapid and sensitive detection of proviral HIV-1 DNA.

    Directory of Open Access Journals (Sweden)

    Lorraine Lillis

    Full Text Available Sensitive diagnostic tests for infectious diseases often employ nucleic acid amplification technologies (NAATs. However, most NAAT assays, including many isothermal amplification methods, require power-dependent instrumentation for incubation. For use in low resource settings (LRS, diagnostics that do not require consistent electricity supply would be ideal. Recombinase polymerase amplification (RPA is an isothermal amplification technology that has been shown to typically work at temperatures ranging from 25-43°C, and does not require a stringent incubation temperature for optimal performance. Here we evaluate the ability to incubate an HIV-1 RPA assay, intended for use as an infant HIV diagnostic in LRS, at ambient temperatures or with a simple non-instrumented heat source. To determine the range of expected ambient temperatures in settings where an HIV-1 infant diagnostic would be of most use, a dataset of the seasonal range of daily temperatures in sub Saharan Africa was analyzed and revealed ambient temperatures as low as 10°C and rarely above 43°C. All 24 of 24 (100% HIV-1 RPA reactions amplified when incubated for 20 minutes between 31°C and 43°C. The amplification from the HIV-1 RPA assay under investigation at temperatures was less consistent below 30°C. Thus, we developed a chemical heater to incubate HIV-1 RPA assays when ambient temperatures are between 10°C and 30°C. All 12/12 (100% reactions amplified with chemical heat incubation from ambient temperatures of 15°C, 20°C, 25°C and 30°C. We also observed that incubation at 30 minutes improved assay performance at lower temperatures where detection was sporadic using 20 minutes incubation. We have demonstrated that incubation of the RPA HIV-1 assay via ambient temperatures or using chemical heaters yields similar results to using electrically powered devices. We propose that this RPA HIV-1 assay may not need dedicated equipment to be a highly sensitive tool to diagnose

  5. Phosphorus recovery by one or two-step technology with use of acids and bases

    Energy Technology Data Exchange (ETDEWEB)

    Stark, Kristina; Hultman, Bengt


    The method of using sludge fractionation is considered to be a sustainable solution where the sludge is seen as the raw material from which products are recovered. This paper will present solutions of advanced technology system for a large wastewater treatment plant. Use of enhanced biological phosphorus removal and fractionation of the sludge in two stages is advantageous both with respect to low necessary chemical and energy demands and recovery efficiency. Phosphorous recovery may be based on one- or two-step technology. Experimental studies have shown that it is possible to recover phosphorus from sludge by the combination of supercritical water oxidation process and alkaline leaching. When the concentration of sodium hydroxide is around 1 M, approximate 50 % of total phosphorus is recovered in room temperature. Meanwhile, over 98 % of the soluble phosphorus is recovered from the liquid phase by adding calcium chloride (CaCl{sub 2}). (author)

  6. Genealogy analysis of duchenne muscular dystrophy by multiplex ligation-dependent probe amplification and sequencing technology%MLPA及测序技术在DMD/BMD家系分析中的应用

    Institute of Scientific and Technical Information of China (English)

    古艳; 谢建生; 都莉; 韩春锡; 万琼


    Objective To analyze the DMD genealogy by MLPA technique in combine with DNA and cDNA sequencing technology. Methods There were 31 individuals accepted DMD gene diagnosis,including 6 DMD/BMD patients, 13 possible carriers and 6 healthy men in 2 DMD/BMD families,moreover 6 healthy women and men were selected from health examination people. Genomic DNA of the peripheral blood was extracted from the pedigrees' members with DMD. RNA was extracted from the bioptic muscle of the DMD patients and was reversed transcription to cDNA. Gene diagnosis was performed for theses pedigrees members using MLPA technique,the mutation was analyzed applying with DNA and/or cDNA sequence technique. Simultaneously,compare the effects of these methods on detecting DMD gene deletion. Results 4 patients of the first DMD family was deleted exon50,and the fetus was confirmed no DMD exons deletion. 2 patients were found deletion exon43 in the second family. MLPA analysis、DNA and cDNA sequencing technology showed the same result. Conclusion MLPA in company with DNA and cDNA sequencing technology could applied into clinical gene diagnosis for DMD.%目的 运用MLPA技术和DNA及cDNA测序技术对DMD/BMD进行家系分析,对患者、可能携带者基因诊断并探讨诊断流程的临床可行性.方法 对2个DMD/BMD家系中6例患者、13例女性可能携带者、6例男性家系成员,6例女性和男性健康对照共31例采集外周血提取DNA,运用MLPA技术分析对以上31例的DMD基因79个外显子;患者取右侧腓肠肌10~30 mg肌肉提取RNA,逆转录cDNA;分别进行DNA及cDNA序列测定,测序结果与MLPA结果进行比较.结果 经MLPA检测,家系1的4例患者均缺失DMD基因Exon50,家系2中2例患者均缺失Exon43.以上结果经肌肉cDNA测序证实了相应外显子缺失.结论 MLPA技术结合DNA及cDNA测序技术进行DMD家系分析具有可靠的临床应用价值.

  7. Single-tube linear DNA amplification for genome-wide studies using a few thousand cells

    NARCIS (Netherlands)

    Shankaranarayanan, P.; Mendoza-Parra, M.A.; Gool, van W.; Trindade, L.M.; Gronemeyer, H.


    Linear amplification of DNA (LinDA) by T7 polymerase is a versatile and robust method for generating sufficient amounts of DNA for genome-wide studies with minute amounts of cells. LinDA can be coupled to a great number of global profiling technologies. Indeed, chromatin immunoprecipitation coupled

  8. 适于转基因产品检测的核酸扩增技术%Alternative DNA Amplification Methods Propitious to GMO Detection

    Institute of Scientific and Technical Information of China (English)



    Nucleic acids, especially forign recombinant DNA, are targets for analysis of genetically modified organisms (GMO). ONA amplification of targets has become the core technology in CMO detection, such as qualitative and quantitative PCR. Along with the increase of GMO and the expansion of planting range, original detection methods have some limitations such as lack of true multiplexing properties. Alternative nucleic acid amplification methods with promising characteristics are summarized in the paper. Special focus is given to the possibilities of using these alternative methods for GMO detection in future.%目前,转基因产品检测主要以核酸为对象,特别是外源重组DNA.靶DNA序列的扩增是转基因产品检测的核心技术,如已经广泛应用的定性、定量PCR技术.随着转基因作物种类的增多、种植范围的扩大,已有方法在某些情况下已不能完全满足检测要求,如高通量多靶标分析.综述了近年来基于核酸水平的检测新技术,并对其未来应用于转基因产品检测进行了分析.

  9. Optimizing Technology to Reduce Mercury and Acid Gas Emissions from Electric Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey C. Quick; David E. Tabet; Sharon Wakefield; Roger L. Bon


    County-average hydrogen values are calculated for the part 2, 1999 Information Collection Request (ICR) coal-quality data, published by the U.S. Environmental Protection Agency. These data are used together with estimated, county-average moisture values to calculate average net heating values for coal produced in U.S. counties. Finally, 10 draft maps of the contiguous U.S. showing the potential uncontrolled sulfur, chlorine and mercury emissions of coal by U.S. county-of-origin, as well as expected mercury emissions calculated for existing emission control technologies, are presented and discussed.

  10. Multiplex amplification of large sets of human exons. (United States)

    Porreca, Gregory J; Zhang, Kun; Li, Jin Billy; Xie, Bin; Austin, Derek; Vassallo, Sara L; LeProust, Emily M; Peck, Bill J; Emig, Christopher J; Dahl, Fredrik; Gao, Yuan; Church, George M; Shendure, Jay


    A new generation of technologies is poised to reduce DNA sequencing costs by several orders of magnitude. But our ability to fully leverage the power of these technologies is crippled by the absence of suitable 'front-end' methods for isolating complex subsets of a mammalian genome at a scale that matches the throughput at which these platforms will routinely operate. We show that targeting oligonucleotides released from programmable microarrays can be used to capture and amplify approximately 10,000 human exons in a single multiplex reaction. Additionally, we show integration of this protocol with ultra-high-throughput sequencing for targeted variation discovery. Although the multiplex capture reaction is highly specific, we found that nonuniform capture is a key issue that will need to be resolved by additional optimization. We anticipate that highly multiplexed methods for targeted amplification will enable the comprehensive resequencing of human exons at a fraction of the cost of whole-genome resequencing.

  11. Organo-erbium systems for optical amplification at telecommunications wavelengths. (United States)

    Ye, H Q; Li, Z; Peng, Y; Wang, C C; Li, T Y; Zheng, Y X; Sapelkin, A; Adamopoulos, G; Hernández, I; Wyatt, P B; Gillin, W P


    Modern telecommunications rely on the transmission and manipulation of optical signals. Optical amplification plays a vital part in this technology, as all components in a real telecommunications system produce some loss. The two main issues with present amplifiers, which rely on erbium ions in a glass matrix, are the difficulty in integration onto a single substrate and the need of high pump power densities to produce gain. Here we show a potential organic optical amplifier material that demonstrates population inversion when pumped from above using low-power visible light. This system is integrated into an organic light-emitting diode demonstrating that electrical pumping can be achieved. This opens the possibility of direct electrically driven optical amplifiers and optical circuits. Our results provide an alternative approach to producing low-cost integrated optics that is compatible with existing silicon photonics and a different route to an effective integrated optics technology.

  12. Regenerative amplification and bifurcations in a burst-mode Nd:YAG laser. (United States)

    Mance, Jason G; Slipchenko, Mikhail N; Roy, Sukesh


    An Nd:YAG-based burst-mode regenerative amplifier laser was developed that offers high extraction efficiency at high repetition rates with low seed energies. The regenerative amplification technique, combined with the burst-mode laser technology, shows promise as an efficient method for amplification of femtojoule-nanojoule pulses up to millijoule energies at repetition rates exceeding 100 kHz. Output energies at repetition rates near the inverse upper state lifetime are limited by bifurcations in the pulse energies of the burst. A model is developed and advantages and limitations are discussed.

  13. Signal amplification in biological and electrical engineering systems: universal role of cascades. (United States)

    Grubelnik, Vladimir; Dugonik, Bogdan; Osebik, Davorin; Marhl, Marko


    In this paper we compare the cascade mechanisms of signal amplification in biological and electrical engineering systems, and show that they share the capacity to considerably amplify signals, and respond to signal changes both quickly and completely, which effectively preserves the form of the input signal. For biological systems, these characteristics are crucial for efficient and reliable cellular signaling. We show that this highly-efficient biological mechanism of signal amplification that has naturally evolved is mathematically fully equivalent with some man-developed amplifiers, which indicates parallels between biological evolution and successful technology development.

  14. Time varying arctic climate change amplification

    Energy Technology Data Exchange (ETDEWEB)

    Chylek, Petr [Los Alamos National Laboratory; Dubey, Manvendra K [Los Alamos National Laboratory; Lesins, Glen [DALLHOUSIE U; Wang, Muyin [NOAA/JISAO


    During the past 130 years the global mean surface air temperature has risen by about 0.75 K. Due to feedbacks -- including the snow/ice albedo feedback -- the warming in the Arctic is expected to proceed at a faster rate than the global average. Climate model simulations suggest that this Arctic amplification produces warming that is two to three times larger than the global mean. Understanding the Arctic amplification is essential for projections of future Arctic climate including sea ice extent and melting of the Greenland ice sheet. We use the temperature records from the Arctic stations to show that (a) the Arctic amplification is larger at latitudes above 700 N compared to those within 64-70oN belt, and that, surprisingly; (b) the ratio of the Arctic to global rate of temperature change is not constant but varies on the decadal timescale. This time dependence will affect future projections of climate changes in the Arctic.

  15. Amplification, Redundancy, and Quantum Chernoff Information (United States)

    Zwolak, Michael; Riedel, C. Jess; Zurek, Wojciech H.


    Amplification was regarded, since the early days of quantum theory, as a mysterious ingredient that endows quantum microstates with macroscopic consequences, key to the "collapse of the wave packet," and a way to avoid embarrassing problems exemplified by Schrödinger's cat. Such a bridge between the quantum microworld and the classical world of our experience was postulated ad hoc in the Copenhagen interpretation. Quantum Darwinism views amplification as replication, in many copies, of the information about quantum states. We show that such amplification is a natural consequence of a broad class of models of decoherence, including the photon environment we use to obtain most of our information. This leads to objective reality via the presence of robust and widely accessible records of selected quantum states. The resulting redundancy (the number of copies deposited in the environment) follows from the quantum Chernoff information that quantifies the information transmitted by a typical elementary subsystem of the environment.

  16. On Arbitrary Phases in Quantum Amplitude Amplification

    CERN Document Server

    Hoyer, P


    We consider the use of arbitrary phases in quantum amplitude amplification which is a generalization of quantum searching. We prove that the phase condition in amplitude amplification is given by $\\tan(\\phi/2)=\\tan(\\phi/2)(1-2a)$, where $\\phi$ and $\\phi$ are the phases used and where $a$ is the success probability of the given algorithm. Thus the choice of phases depends nontrivially and nonlinearly on the success probability. Utilizing this condition, we give methods for constructing quantum algorithms that succeed with certainty and for implementing arbitrary rotations. We also conclude that phase errors of order up to $\\frac{1}{\\sqrt{a}}$ can be tolerated in amplitude amplification.

  17. Assessment of technological options and economical feasibility for cyanophycin biopolymer and high-value amino acid production (United States)

    Oosterhuis, Nico; Giuseppin, Marco; Toonen, Marcel; Franssen, Henk; Scott, Elinor; Sanders, Johan; Steinbüchel, Alexander


    Major transitions can be expected within the next few decades aiming at the reduction of pollution and global warming and at energy saving measures. For these purposes, new sustainable biorefinery concepts will be needed that will replace the traditional mineral oil-based synthesis of specialty and bulk chemicals. An important group of these chemicals are those that comprise N-functionalities. Many plant components contained in biomass rest or waste stream fractions contain these N-functionalities in proteins and free amino acids that can be used as starting materials for the synthesis of biopolymers and chemicals. This paper describes the economic and technological feasibility for cyanophycin production by fermentation of the potato waste stream Protamylasse™ or directly in plants and its subsequent conversion to a number of N-containing bulk chemicals. PMID:17876577

  18. Sulfur Recovery from Acid Gas Using the Claus Process and High Temperature Air Combustion (HiTAC Technology

    Directory of Open Access Journals (Sweden)

    Mohamed Sassi


    Full Text Available Sulfur-bearing compounds are very detrimental to the environment and to industrial process equipment. They are often obtained or formed as a by-product of separation and thermal processing of fuels containing sulfur, such as coal, crude oil and natural gas. The two sulfur compounds, which need special attention, are: hydrogen sulfide (H2S and sulfur dioxide (SO2. H2S is a highly corrosive gas with a foul smell. SO2 is a toxic gas responsible for acid rain formation and equipment corrosion. Various methods of reducing pollutants containing sulfur are described in this paper, with a focus on the modified Claus process, enhanced by the use of High Temperature Air Combustion (HiTAC technology in the Claus furnace. The Claus process has been known and used in the industry for over 100 years. It involves thermal oxidation of hydrogen sulfide and its reaction with sulfur dioxide to form sulfur and water vapor. This process is equilibrium-limited and usually achieves efficiencies in the range of 94-97%, which have been regarded as acceptable in the past years. Nowadays strict air pollution regulations regarding hydrogen sulfide and sulfur dioxide emissions call for nearly 100% efficiency, which can only be achieved with process modifications. High temperature air combustion technology or otherwise called flameless (or colorless combustion is proposed here for application in Claus furnaces, especially those employing lean acid gas streams, which cannot be burned without the use of auxiliary fuel or oxygen enrichment under standard conditions. With the use of HiTAC it has been shown, however, that fuel-lean, Low Calorific Value (LCV fuels can be burned with very uniform thermal fields without the need for fuel enrichment or oxygen addition. The uniform temperature distribution favors clean and efficient burning with an additional advantage of significant reduction of NOx, CO and hydrocarbon emission.

  19. Continuous phase amplification with a Sagnac interferometer

    CERN Document Server

    Starling, David J; Williams, Nathan S; Jordan, Andrew N; Howell, John C


    We describe a weak value inspired phase amplification technique in a Sagnac interferometer. We monitor the relative phase between two paths of a slightly misaligned interferometer by measuring the average position of a split-Gaussian mode in the dark port. Although we monitor only the dark port, we show that the signal varies linearly with phase and that we can obtain similar sensitivity to balanced homodyne detection. We derive the source of the amplification both with classical wave optics and as an inverse weak value.

  20. Effective Privacy Amplification for Secure Classical Communications

    CERN Document Server

    Horvath, Tamas; Scheuer, Jacob


    We study the effectiveness of privacy amplification for classical key-distribution schemes. We find that, unlike quantum key distribution schemes, the high fidelity of the raw key in classical systems allow the users to always sift a secure shorter key, given that they have an upper bound of eavesdropper probability to correctly guess the exchanged key-bits. We establish the number of privacy amplification iterations needed to achieve information leak of 10^-8 in several classical systems and highlight the inherent tradeoff between the number of iterations and the security of the raw key.

  1. Parametric Amplification For Detecting Weak Optical Signals (United States)

    Hemmati, Hamid; Chen, Chien; Chakravarthi, Prakash


    Optical-communication receivers of proposed type implement high-sensitivity scheme of optical parametric amplification followed by direct detection for reception of extremely weak signals. Incorporates both optical parametric amplification and direct detection into optimized design enhancing effective signal-to-noise ratios during reception in photon-starved (photon-counting) regime. Eliminates need for complexity of heterodyne detection scheme and partly overcomes limitations imposed on older direct-detection schemes by noise generated in receivers and by limits on quantum efficiencies of photodetectors.

  2. A dual amplification fluorescent strategy for sensitive detection of DNA methyltransferase activity based on strand displacement amplification and DNAzyme amplification. (United States)

    Cui, Wanling; Wang, Lei; Jiang, Wei


    DNA methyltransferase (MTase) plays a critical role in many biological processes and has been regarded as a predictive cancer biomarker and a therapeutic target in cancer treatment. Sensitive detection of DNA MTase activity is essential for early cancer diagnosis and therapeutics. Here, we developed a dual amplification fluorescent strategy for sensitive detection of DNA MTase activity based on strand displacement amplification (SDA) and DNAzyme amplification. A trifunctional double-stranded DNA (dsDNA) probe was designed including a methylation site for DNA MTase recognition, a complementary sequence of 8-17 DNAzyme for synthesizing DNAzyme, and a nicking site for nicking enzyme cleavage. Firstly, the trifunctional dsDNA probe was methylated by DNA MTase to form the methylated dsDNA. Subsequently, HpaII restriction endonuclease specifically cleaved the residue of unmethylated dsDNA. Next, under the action of polymerase and nicking enzyme, the methylared dsDNA initiated SDA, releasing numbers of 8-17 DNAzymes. Finally, the released 8-17 DNAzymes triggered DNAzyme amplification reaction to induce a significant fluorescence enhancement. This strategy could detect DNA MTase activity as low as 0.0082U/mL. Additionally, the strategy was successfully applied for evaluating the inhibitions of DNA MTase using two anticancer drugs, 5-azacytidine and 5-aza-2'-deoxycytidine. The results indicate the proposed strategy has a potential application in early cancer diagnosis and therapeutics.

  3. Fatty-acid alkyl esters in table olives in relation to abnormal fermentation and poorly conducted technological treatments

    Directory of Open Access Journals (Sweden)

    Lanza, B.


    Full Text Available There are several methods to prepare table olives, and each of the steps and conditions during this processing can affect the composition and nutritional value of the product. The influence of abnormal fermentation and poorly conducted technological treatments was examined here in terms of the lipid fraction of table olives. In ‘Greek style’ olives, a low concentration of brine can allow the growth of spontaneous microflora and consequent organoleptic defects (‘putrid/butyric fermentation’, ‘winey-vinegary’. Here, the ‘Kalamata’ and ‘Moresca’ cultivars can produce methyl esters (methyl oleate/ linoleate: 553 and 450 mg·kg-1 oil, respectively and ethyl esters (ethyl oleate/ inoleate: 4764 and 4195; palmitate: 617 and 886 mg·kg-1 oil, respectively. In ‘Sevillan style’ olives, a high NaOH concentration influences the fatty-acid composition less, but is difficult to eliminate, for a ‘soapy’ defect. The ‘Giarraffa’ and ‘Nocellara del Belice’ cultivars produce only ethyl esters (ethyl oleate/ linoleate: 222 and 289 mg·kg-1 oil, respectively. With this production of ethyl and methyl esters from the principal fatty acids in the lipid fractions of table olives, methods that provide only biological treatments (i.e., Greek style pose more risk than methods that provide only chemical treatments (i.e., Sevillan style.H

  4. The art of strain improvement of industrial lactic acid bacteria without the use of recombinant DNA technology. (United States)

    Derkx, Patrick M F; Janzen, Thomas; Sørensen, Kim I; Christensen, Jeffrey E; Stuer-Lauridsen, Birgitte; Johansen, Eric


    The food industry is constantly striving to develop new products to fulfil the ever changing demands of consumers and the strict requirements of regulatory agencies. For foods based on microbial fermentation, this pushes the boundaries of microbial performance and requires the constant development of new starter cultures with novel properties. Since the use of ingredients in the food industry is tightly regulated and under close scrutiny by consumers, the use of recombinant DNA technology to improve microbial performance is currently not an option. As a result, the focus for improving strains for microbial fermentation is on classical strain improvement methods. Here we review the use of these techniques to improve the functionality of lactic acid bacteria starter cultures for application in industrial-scale food production. Methods will be described for improving the bacteriophage resistance of specific strains, improving their texture forming ability, increasing their tolerance to stress and modulating both the amount and identity of acids produced during fermentation. In addition, approaches to eliminating undesirable properties will be described. Techniques include random mutagenesis, directed evolution and dominant selection schemes.

  5. The application of nucleic acid sequence?based amplification,real?time PCR and GM test in invasive aspergillosis diagnosis%核酸序列依赖性扩增、Real?time PCR及GM试验诊断侵袭性曲霉菌感染的临床应用评价

    Institute of Scientific and Technical Information of China (English)

    王立朋; 鲍翠霞; 于丽梅; 张晓录; 于威娟; 张霞; 李玮; 黄葆华; 李杰


    Objective To study the diagnostic performance of nucleic acid sequence?based amplification ( NASBA) assay,real?time PCR and GM test in detecting invasive aspergillosis for clinical diagnosis.Methods Blood samples from 80 patients at a high risk for IA were collected during from November 2013 to June 2014.These patients were categorized as 8 proven IA,26 probable IA, and 46 non?IA according to the 2008 revised definitions of EORTC/MSG.Blood samples were tested by NASBA,real?time PCR and GM test and their diagnostic parameters were calculated,respectively.Result The sensitivity of NASBA,real?time PCR and GM test was 76.47%,67.65% and 52.94%,while their specificity was 80.43%,89.13%,80.43%,respectively.The efficiency of various com?binations of tests was also evaluated.Perfect specificity (100%) and positive predictive value (100%) were achieved by combining NASBA and real?time PCR as a serial testing.A combination of NASBA and real?time PCR as a parallel testing was the most sensitive (94.12%).Conclusion The sensitivity and specificity of NASBA and real?time PCR were superior to GM test.Combination of these assays could be particularly useful in specific clinical situations.%目的 核酸序列依赖性扩增 ( nucleic acid sequence?based amplification,NASBA)、Real?time PCR及GM试验在侵袭性曲霉菌感染中的诊断价值. 方法 收集2013年11月~2014年6月临床上曲霉菌感染高危病患的血液标本80例,并根据EORTC/MSG诊断标准分为确诊组8例,拟诊组26例,非感染组46例,分别利用NASBA、real?time PCR及GM试验进行检测,计算3种方法的诊断指标并分析评价. 结果 NASBA、real?time PCR及GM试验3种方法的灵敏度分别为76.47%、67.65%、52.94%,特异度分别为80.43%、89.13%、80.43%. 联合诊断结果显示,NASBA与real?time PCR串联方案有最好的特异度 (100%)及阳性预测值(100%);NASBA与real?time PCR并联方案则最为灵敏(94.12%). 结论 NASBA用于诊断IA最为敏感,而real?time PCR


    Gokadze, S; Barbakadze, V; Mulkijanyan, K; Bakuridze, L; Bakuridze, A


    One of the most actual problems of pharmacy is the development of medication forms for external application with complex effects on (gel, emplastro, aerosol, etc.) skin wounds, burns and inflammatory factors. The centuries-old practice of using phyto-preparations (herbal remedies) proved that they have fewer side effects in comparison with synthetic drugs. Despite the wide application of herbal preparations, in the literature there is a little information about their application in development of wound and burn healing modern dosage forms. Among the medicinal plants with the mentioned pharmacological actions, comfrey (Symphytum L.) should be distinguished. Phenolic polymer poly[3-(3,4-dihydroxyphenyl)glyceric acid] (PDGA) or poly[oxy-1-carboxy-2-(3,4-dihydroxyphenyl)ethylene], amounting approximately 25% of polysaccharides and 1.5-2.5% of dry plant material, were isolated from the roots and stems of Caucasian comfrey species (S. asperum, S. caucasicum). Contrary to polysaccharides this phenolic polymer of Comfrey appeared to have a high immunomodulatory (anticomplement), antioxidative, antilipoperoxidantive, anti-inflammatory and wound-healing efficacy/activities. The aim of the study was development of the composition and technology of PDGA-containing gel. According to the results of complex biopharmaceutical studies PDGA gel optimal composition has been proved. The technological scheme for preparation of PDGA gel has been developed. PDGA gel stability under normal conditions of storage at +40С was studied. The gel has a shelf life (determined expiration date) of 2 year.


    Directory of Open Access Journals (Sweden)

    Sofia Ton


    Full Text Available Near infrared transmittance (NIT, 850 to 1048 nm spectroscopy was used to predict groups of fatty acids (FA, namely saturated FA (SFA, monounsaturated FA (MUFA and polyunsaturated FA (PUFA, in commercial ground meat samples aiming to develope a fast and reliable method for their determination in support of label declaration by the new EC Regulation 1169/2011. Dataset was built using 81 samples of commercial ground meat from different species: beef, pork, chicken and turkey. In some samples, meat was mixtured with different ingredients such as bread, cheese, spices and additives. Samples were first analysed by NIT instrument for spectral information and reference FA values were obtained by gas chromatographic analysis. Prediction models for SFA, MUFA and PUFA expressed on total FA exhibited coefficients of determination of calibration of 0.822, 0.367 and 0.780 on intact samples, and 0.879, 0.726 and 0.908 on minced samples, respectively. Good results were also obtained when FA groups were expressed as g/100g of fresh meat: the coefficient of determination of calibration increased to values larger than 0.915. Moreover, comparing the slightly lower coefficient of determination in crossvalidation of intact compared with minced meat suggested that equations developed for minced samples were more accurate than those built for intact products. Results highlighted the effectiveness of NIT spectroscopy to predict the major FA groups in commercial meat products.

  8. Genetic and Technological Characterisation of Vineyard- and Winery-Associated Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Aspasia A. Nisiotou


    Full Text Available Vineyard- and winery-associated lactic acid bacteria (LAB from two major PDO regions in Greece, Peza and Nemea, were surveyed. LAB were isolated from grapes, fermenting musts, and winery tanks performing spontaneous malolactic fermentations (MLF. Higher population density and species richness were detected in Nemea than in Peza vineyards and on grapes than in fermenting musts. Pediococcus pentosaceus and Lactobacillus graminis were the most abundant LAB on grapes, while Lactobacillus plantarum dominated in fermenting musts from both regions. No particular structure of Lactobacillus plantarum populations according to the region of origin was observed, and strain distribution seems random. LAB species diversity in winery tanks differed significantly from that in vineyard samples, consisting principally of Oenococcus oeni. Different strains were analysed as per their enological characteristics and the ability to produce biogenic amines (BAs. Winery-associated species showed higher resistance to low pH, ethanol, SO2, and CuSO4 than vineyard-associated isolates. The frequency of BA-producing strains was relatively low but not negligible, considering that certain winery-associated Lactobacillus hilgardii strains were able to produce BAs. Present results show the necessity of controlling the MLF by selected starters in order to avoid BA accumulation in wine.

  9. Method Of Signal Amplification In Multi-Chromophore Luminescence Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Levitsky, Igor A. (Fall River, MA); Krivoshlykov, Sergei G. (Shrewsbury, MA)


    A fluorescence-based method for highly sensitive and selective detection of analyte molecules is proposed. The method employs the energy transfer between two or more fluorescent chromophores in a carefully selected polymer matrix. In one preferred embodiment, signal amplification has been achieved in the fluorescent sensing of dimethyl methylphosphonate (DMMP) using two dyes, 3-aminofluoranthene (AM) and Nile Red (NR), in a hydrogen bond acidic polymer matrix. The selected polymer matrix quenches the fluorescence of both dyes and shifts dye emission and absorption spectra relative to more inert matrices. Upon DMMP sorption, the AM fluorescence shifts to the red at the same time the NR absorption shifts to the blue, resulting in better band overlap and increased energy transfer between chromophores. In another preferred embodiment, the sensitive material is incorporated into an optical fiber system enabling efficient excitation of the dye and collecting the fluorescent signal form the sensitive material on the remote end of the system. The proposed method can be applied to multichromophore luminescence sensor systems incorporating N-chromophores leading to N-fold signal amplification and improved selectivity. The method can be used in all applications where highly sensitive detection of basic gases, such as dimethyl methylphosphonate (DMMP), Sarin, Soman and other chemical warfare agents having basic properties, is required, including environmental monitoring, chemical industry and medicine.

  10. DNA Extraction and Amplification from Contemporary Polynesian Bark-Cloth (United States)

    Moncada, Ximena; Payacán, Claudia; Arriaza, Francisco; Lobos, Sergio; Seelenfreund, Daniela; Seelenfreund, Andrea


    Background Paper mulberry has been used for thousands of years in Asia and Oceania for making paper and bark-cloth, respectively. Museums around the world hold valuable collections of Polynesian bark-cloth. Genetic analysis of the plant fibers from which the textiles were made may answer a number of questions of interest related to provenance, authenticity or species used in the manufacture of these textiles. Recovery of nucleic acids from paper mulberry bark-cloth has not been reported before. Methodology We describe a simple method for the extraction of PCR-amplifiable DNA from small samples of contemporary Polynesian bark-cloth (tapa) using two types of nuclear markers. We report the amplification of about 300 bp sequences of the ITS1 region and of a microsatellite marker. Conclusions Sufficient DNA was retrieved from all bark-cloth samples to permit successful PCR amplification. This method shows a means of obtaining useful genetic information from modern bark-cloth samples and opens perspectives for the analyses of small fragments derived from ethnographic materials. PMID:23437166

  11. DNA extraction and amplification from contemporary Polynesian bark-cloth.

    Directory of Open Access Journals (Sweden)

    Ximena Moncada

    Full Text Available BACKGROUND: Paper mulberry has been used for thousands of years in Asia and Oceania for making paper and bark-cloth, respectively. Museums around the world hold valuable collections of Polynesian bark-cloth. Genetic analysis of the plant fibers from which the textiles were made may answer a number of questions of interest related to provenance, authenticity or species used in the manufacture of these textiles. Recovery of nucleic acids from paper mulberry bark-cloth has not been reported before. METHODOLOGY: We describe a simple method for the extraction of PCR-amplifiable DNA from small samples of contemporary Polynesian bark-cloth (tapa using two types of nuclear markers. We report the amplification of about 300 bp sequences of the ITS1 region and of a microsatellite marker. CONCLUSIONS: Sufficient DNA was retrieved from all bark-cloth samples to permit successful PCR amplification. This method shows a means of obtaining useful genetic information from modern bark-cloth samples and opens perspectives for the analyses of small fragments derived from ethnographic materials.

  12. 滚环扩增技术及其在生物分子诊断中的应用%Rolling Circle Amplification and Its Application in bio-molecular Diagnosis

    Institute of Scientific and Technical Information of China (English)

    周小明; 邢达


    滚环扩增技术(RCA)是近年来发展起来的一种新型的核酸扩增技术.该技术是基于连接酶连接、引物延伸、与链置换扩增反应的一种等温核酸扩增方法.在恒温的条件下,可以产生大量的与环型探针互补的重复序列.与传统的核酸扩增方法相比,它具有扩增条件简单,特异性高,能在恒温条件下进行等特点.滚环扩增技术结合荧光、电化学、电化学发光等检测技术可以实现高灵敏的生物分子检测.这些特点使得滚环扩增技术在生物分子诊断领域具有潜在的应用价值.本文概述了滚环扩增技术的基本原理,详细地介绍了滚环扩增技术在当前生物检测中的应用现状,并对其前景作了展望.%Rolling circle amplification ( RCA) is a new type of nucleic acid amplification technology developed in recent years. It is based on the amplification of a circularizable oligonucleotide probe ( C-probe) , which is ligated by DNA ligase. Under isothermal condition, C-probe can be amplified and can generate multimeric single-stranded DNA ( ssDNA) complementary to C-probe. Compared with traditional nucleic acid amplification method, RCA is a simpler amplification method with high specificity. Combined with fluorescence detection, electrochemical detection, electrochemiluminescence detection, et al, RCA can be applied to high sensitive analysis of bio-molecules. Due to the fact that RCA can be carried out under constant temperature conditions, this feature make RCA hold great potential in the field of point-of-care diagnosis. This article outlines the basic principles of RCA, the detailed description of the current status of rolling circle amplification in biological detection, and its future prospects.

  13. Intelligence amplification framework for enhancing scheduling processes

    NARCIS (Netherlands)

    Dobrkovic, Andrej; Liu, Luyao; Iacob, Maria-Eugenia; Hillegersberg, van Jos


    The scheduling process in a typical business environment consists of predominantly repetitive tasks that have to be completed in limited time and often containing some form of uncertainty. The intelligence amplification is a symbiotic relationship between a human and an intelligent agent. This partn

  14. Social amplification of risk: a conceptual framework

    Energy Technology Data Exchange (ETDEWEB)

    Kasperson, R.E.; Renn, O.; Slovic, P.; Brown, H.S.; Emel, J.; Goble, R.; Kasperson, J.X.; Ratick, S.


    One of the most perplexing problems in risk analysis is why some relatively minor risks or risk events, as assessed by technical experts, often elicit strong public concerns and result in substantial impacts upon society and economy. This article sets forth a conceptual framework that seeks to link systematically the technical assessment of risk with psychological, sociological, and cultural perspectives of risk perception and risk-related behavior. The main thesis is that hazards interact with psychological, social, institutional, and cultural processes in ways that may amplify or attenuate public responses to the risk or risk event. A structural description of the social amplification of risk is now possible. Amplification occurs at two stages: in the transfer of information about the risk, and in the response mechanisms of society. Signals about risk are processed by individual and social amplification stations, including the scientist who communicates the risk assessment, the news media, cultural groups, interpersonal networks, and others. Key steps of amplifications can be identified at each stage. The amplified risk leads to behavioral responses, which, in turn, result in secondary impacts. Models are presented that portray the elements and linkages in the proposed conceptual framework.

  15. Desert Amplification in a Warming Climate (United States)

    Zhou, Liming


    Here I analyze the observed and projected surface temperature anomalies over land between 50°S-50°N for the period 1950–2099 by large-scale ecoregion and find strongest warming consistently and persistently seen over driest ecoregions such as the Sahara desert and the Arabian Peninsula during various 30-year periods, pointing to desert amplification in a warming climate. This amplification enhances linearly with the global mean greenhouse gases(GHGs) radiative forcing and is attributable primarily to a stronger GHGs-enhanced downward longwave radiation forcing reaching the surface over drier ecoregions as a consequence of a warmer and thus moister atmosphere in response to increasing GHGs. These results indicate that desert amplification may represent a fundamental pattern of global warming associated with water vapor feedbacks over land in low- and mid- latitudes where surface warming rates depend inversely on ecosystem dryness. It is likely that desert amplification might involve two types of water vapor feedbacks that maximize respectively in the tropical upper troposphere and near the surface over deserts, with both being very dry and thus extremely sensitive to changes of water vapor.

  16. Fin width and height dependence of bipolar amplification in bulk FinFETs submitted to heavy ion irradiation

    Institute of Scientific and Technical Information of China (English)

    于俊庭; 陈书明; 陈建军; 黄鹏程


    FinFET technologies are becoming the mainstream process as technology scales down. Based on a 28-nm bulk p-FinFET device, we have investigated the fin width and height dependence of bipolar amplification for heavy-ion-irradiated FinFETs by 3D TCAD numerical simulation. Simulation results show that due to a well bipolar conduction mechanism rather than a channel (fin) conduction path, the transistors with narrower fins exhibit a diminished bipolar amplification effect, while the fin height presents a trivial effect on the bipolar amplification and charge collection. The results also indicate that the single event transient (SET) pulse width can be mitigated about 35%at least by optimizing the ratio of fin width and height, which can provide guidance for radiation-hardened applications in bulk FinFET technology.


    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey C. Quick; David E. Tabet; Sharon Wakefield; Roger L. Bon


    Maps showing potential mercury, sulfur, chlorine, and moisture emissions for U.S. coal by county of origin were made from publicly available data (plates 1, 2, 3, and 4). Published equations that predict mercury capture by emission control technologies used at U.S. coal-fired utilities were applied to average coal quality values for 169 U.S. counties. The results were used to create five maps that show the influence of coal origin on mercury emissions from utility units with: (1) hot-side electrostatic precipitator (hESP), (2) cold-side electrostatic precipitator (cESP), (3) hot-side electrostatic precipitator with wet flue gas desulfurization (hESP/FGD), (4) cold-side electrostatic precipitator with wet flue gas desulfurization (cESP/FGD), and (5) spray-dry adsorption with fabric filter (SDA/FF) emission controls (plates 5, 6, 7, 8, and 9). Net (lower) coal heating values were calculated from measured coal Btu values, and estimated coal moisture and hydrogen values; the net heating values were used to derive mercury emission rates on an electric output basis (plate 10). Results indicate that selection of low-mercury coal is a good mercury control option for plants having hESP, cESP, or hESP/FGD emission controls. Chlorine content is more important for plants having cESP/FGD or SDA/FF controls; optimum mercury capture is indicated where chlorine is between 500 and 1000 ppm. Selection of low-sulfur coal should improve mercury capture where carbon in fly ash is used to reduce mercury emissions. Comparison of in-ground coal quality with the quality of commercially mined coal indicates that existing coal mining and coal washing practice results in a 25% reduction of mercury in U.S. coal before it is delivered to the power plant. Further pre-combustion mercury reductions may be possible, especially for coal from Texas, Ohio, parts of Pennsylvania and much of the western U.S.

  18. Assessment of whole genome amplification-induced bias through high-throughput, massively parallel whole genome sequencing

    Directory of Open Access Journals (Sweden)

    Plant Ramona N


    Full Text Available Abstract Background Whole genome amplification is an increasingly common technique through which minute amounts of DNA can be multiplied to generate quantities suitable for genetic testing and analysis. Questions of amplification-induced error and template bias generated by these methods have previously been addressed through either small scale (SNPs or large scale (CGH array, FISH methodologies. Here we utilized whole genome sequencing to assess amplification-induced bias in both coding and non-coding regions of two bacterial genomes. Halobacterium species NRC-1 DNA and Campylobacter jejuni were amplified by several common, commercially available protocols: multiple displacement amplification, primer extension pre-amplification and degenerate oligonucleotide primed PCR. The amplification-induced bias of each method was assessed by sequencing both genomes in their entirety using the 454 Sequencing System technology and comparing the results with those obtained from unamplified controls. Results All amplification methodologies induced statistically significant bias relative to the unamplified control. For the Halobacterium species NRC-1 genome, assessed at 100 base resolution, the D-statistics from GenomiPhi-amplified material were 119 times greater than those from unamplified material, 164.0 times greater for Repli-G, 165.0 times greater for PEP-PCR and 252.0 times greater than the unamplified controls for DOP-PCR. For Campylobacter jejuni, also analyzed at 100 base resolution, the D-statistics from GenomiPhi-amplified material were 15 times greater than those from unamplified material, 19.8 times greater for Repli-G, 61.8 times greater for PEP-PCR and 220.5 times greater than the unamplified controls for DOP-PCR. Conclusion Of the amplification methodologies examined in this paper, the multiple displacement amplification products generated the least bias, and produced significantly higher yields of amplified DNA.

  19. 电子级氢氟酸的纯化技术及其配套技术%Purification Technology for Electronic -Grade Hydrofluoric Acid and Its Associated Technology

    Institute of Scientific and Technical Information of China (English)

    洪海江; 应振洲; 余锋; 陈文亮; 赵景平


    With the shift of the semiconductor chip and Liquid Crystal Display (LCD) manufactuning to China, and the increasing demand for electronic - grade hydrofluoric acid in china, the fine fluorine chemical industry has become a trend for the the development of hydrofluoric Acid industry in China. The application area, quality criteria and purification technology for electronic -grade hydrofluoric acid are outlined, as well as associated tech- nology for production of electronic - grade hydrofluoric acid. It is suggested that while improving the production technology for electronic -grade hydrofluoric acid, the R&D for its associated technology should also be strengthened.%随着半导体芯片和液晶显示器(LCD)制造业向我国转移,以及国内电子级氢氟酸需求量的日益增长,精细氟化工已成为我国氟化工业发展的必然趋势。阐述了电子级氢氟酸的应用领域、质量标准、纯化技术,以及生产电子级氢氟酸的配套技术,认为我国在提高电子级氢氟酸生产工艺水平的同时,应加强其配套技术的研发。

  20. Rapid microfluidic thermal cycler for nucleic acid amplification

    Energy Technology Data Exchange (ETDEWEB)

    Beer, Neil Reginald; Vafai, Kambiz


    A system for thermal cycling a material to be thermal cycled including a microfluidic heat exchanger; a porous medium in the microfluidic heat exchanger; a microfluidic thermal cycling chamber containing the material to be thermal cycled, the microfluidic thermal cycling chamber operatively connected to the microfluidic heat exchanger; a working fluid at first temperature; a first system for transmitting the working fluid at first temperature to the microfluidic heat exchanger; a working fluid at a second temperature, a second system for transmitting the working fluid at second temperature to the microfluidic heat exchanger; a pump for flowing the working fluid at the first temperature from the first system to the microfluidic heat exchanger and through the porous medium; and flowing the working fluid at the second temperature from the second system to the heat exchanger and through the porous medium.

  1. A new evolutionary theory deduced mathematically from entropy amplification

    Institute of Scientific and Technical Information of China (English)


    A new evolutionary theory which is able to unite the present evolutionary debates is deduced mathematically from the principle of entropy amplification.It suggests that the extensive evolution is driven by the amplification of entropy,or microscopic diversity,and the biological evolution is driven by the amplification of biodiversity.Forming high hierarchies is the most important way for the amplification and brings out spontaneously three kinds of selection.This theory has some positive cultural meanings.

  2. Integrated sample-to-detection chip for nucleic acid test assays. (United States)

    Prakash, R; Pabbaraju, K; Wong, S; Tellier, R; Kaler, K V I S


    Nucleic acid based diagnostic techniques are routinely used for the detection of infectious agents. Most of these assays rely on nucleic acid extraction platforms for the extraction and purification of nucleic acids and a separate real-time PCR platform for quantitative nucleic acid amplification tests (NATs). Several microfluidic lab on chip (LOC) technologies have been developed, where mechanical and chemical methods are used for the extraction and purification of nucleic acids. Microfluidic technologies have also been effectively utilized for chip based real-time PCR assays. However, there are few examples of microfluidic systems which have successfully integrated these two key processes. In this study, we have implemented an electro-actuation based LOC micro-device that leverages multi-frequency actuation of samples and reagents droplets for chip based nucleic acid extraction and real-time, reverse transcription (RT) PCR (qRT-PCR) amplification from clinical samples. Our prototype micro-device combines chemical lysis with electric field assisted isolation of nucleic acid in a four channel parallel processing scheme. Furthermore, a four channel parallel qRT-PCR amplification and detection assay is integrated to deliver the sample-to-detection NAT chip. The NAT chip combines dielectrophoresis and electrostatic/electrowetting actuation methods with resistive micro-heaters and temperature sensors to perform chip based integrated NATs. The two chip modules have been validated using different panels of clinical samples and their performance compared with standard platforms. This study has established that our integrated NAT chip system has a sensitivity and specificity comparable to that of the standard platforms while providing up to 10 fold reduction in sample/reagent volumes.

  3. Amplification and Re-Generation of LNA-Modified Libraries

    DEFF Research Database (Denmark)

    Doessing, Holger; Hansen, Lykke H.; Veedu, Rakesh N.;


    Locked nucleic acids (LNA) confer high thermal stability and nuclease resistance to oligonucleotides. The discovery of polymerases that accept LNA triphosphates has led us to propose a scheme for the amplification and re-generation of LNA-containing oligonucleotide libraries. Such libraries could...... be used for in vitro selection of e.g., native LNA aptamers. We maintained an oligonucleotide library encoding 40 randomized positions with LNA ATP, GTP, CTP, and TTP for 7 rounds of ‘mock’ in vitro selection in the absence of a target and analyzed the sequence composition after rounds 1, 4 and 7. We...... observed a decrease in LNA-A content from 20.5% in round 1 to 6.6% in round 7. This decrease was accompanied by a substantial bias against successive LNA-As (poly-LNA adenosine tracts) and a relative over-representation of single LNA-As. Maintaining a library with LNA TTP yielded similar results. Together...

  4. Effects of different fat sources, technological forms and characteristics of the basal diet on milk fatty acid profile in lactating dairy cows - a meta-analysis

    NARCIS (Netherlands)

    Sterk, A.R.; Vuuren, van A.M.; Hendriks, W.H.; Dijkstra, J.


    A meta-analysis was conducted to study milk fatty acid (FA) profile in dairy cows in response to changes in dietary nutrient composition in relation to supplementation of fat sources, their technological form, addition of fish oil and main forage type in the basal diet. Data comprised 151 treatment

  5. Isothermal DNA amplification in bioanalysis: strategies and applications. (United States)

    Kim, Joonyul; Easley, Christopher J


    Isothermal DNA amplification is an alternative to PCR-based amplification for point-of-care diagnosis. Since the early 1990s, the approach has been refined into a simple, rapid and cost-effective tool by means of several distinct strategies. Input signals have been diversified from DNA to RNA, protein or small organic molecules by translating these signals into input DNA before amplification, thus allowing assays on various classes of biomolecules. In situ detection of single biomolecules has been achieved using an isothermal method, leveraging localized signal amplification in an intact specimen. A few pioneering studies to develop a homogenous isothermal protein assay have successfully translated structure-switching of a probe upon target binding into input DNA for isothermal amplification. In addition to the detection of specific targets, isothermal methods have made whole-genome amplification of single cells possible owing to the unbiased, linear nature of the amplification process as well as the large size of amplified products given by ϕ29 DNA polymerase. These applications have been devised with the four isothermal amplification strategies covered in this review: strand-displacement amplification, rolling circle amplification, helicase-dependent amplification and recombinase polymerase amplification.

  6. Plasmonic Terahertz Amplification in Graphene-Based Asymmetric Hyperbolic Metamaterial

    Directory of Open Access Journals (Sweden)

    Igor Nefedov


    Full Text Available We propose and theoretically explore terahertz amplification, based on stimulated generation of plasmons in graphene asymmetric hyperbolic metamaterials (AHMM, strongly coupled to terahertz radiation. In contrast to the terahertz amplification in resonant nanocavities, AHMM provides a wide-band THz amplification without any reflection in optically thin graphene multilayers.

  7. Plasmonic Terahertz Amplification in Graphene-Based Asymmetric Hyperbolic Metamaterial


    Igor Nefedov; Leonid Melnikov


    We propose and theoretically explore terahertz amplification, based on stimulated generation of plasmons in graphene asymmetric hyperbolic metamaterials (AHMM), strongly coupled to terahertz radiation. In contrast to the terahertz amplification in resonant nanocavities, AHMM provides a wide-band THz amplification without any reflection in optically thin graphene multilayers.

  8. Blending problem-based learning with Web technology positively impacts student learning outcomes in acid-base physiology. (United States)

    Taradi, Suncana Kukolja; Taradi, Milan; Radic, Kresimir; Pokrajac, Niksa


    World Wide Web (Web)-based learning (WBL), problem-based learning (PBL), and collaborative learning are at present the most powerful educational options in higher education. A blended (hybrid) course combines traditional face-to-face and WBL approaches in an educational environment that is nonspecific as to time and place. To provide educational services for an undergraduate second-year elective course in acid-base physiology, a rich, student-centered educational Web-environment designed to support PBL was created by using Web Course Tools courseware. The course is designed to require students to work in small collaborative groups using problem solving activities to develop topic understanding. The aim of the study was to identify the impact of the blended WBL-PBL-collaborative learning environment on student learning outcomes. Student test scores and satisfaction survey results from a blended WBL-PBL-based test group (n = 37) were compared with a control group whose instructional opportunities were from a traditional in-class PBL model (n = 84). WBL students scored significantly (t = 3.3952; P = 0.0009) better on the final acid-base physiology examination and expressed a positive attitude to the new learning environment in the satisfaction survey. Expressed in terms of a difference effect, the mean of the treated group (WBL) is at the 76th percentile of the untreated (face-to-face) group, which stands for a "medium" effect size. Thus student progress in the blended WBL-PBL collaborative environment was positively affected by the use of technology.

  9. New Developments in Quantitative Real-time Polymerase Chain Reaction Technology. (United States)

    Gadkar, Vija yJ; Filion, Martin


    Real time-quantitative PCR (RT-qPCR) technology has revolutionized the detection landscape in every area of molecular biology. The fundamental basis of this technology has remained unchanged since its inception, however various modifications have enhanced the overall performance of this highly versatile technology. These improvements have ranged from changes in the individual components of the enzymatic reaction cocktail (polymerizing enzymes, reaction buffers, probes, etc.) to the detection system itself (instrumentation, software, etc.). The RT-qPCR technology currently available to researchers is more sensitive, faster and affordable than when this technology was first introduced. In this article, we summarize the developments of the last few years in RT-qPCR technology and nucleic acid amplification.

  10. Detection of microRNAs in frozen tissue sections by fluorescence in situ hybridization using locked nucleicacid probes and tyramide signal amplification

    DEFF Research Database (Denmark)

    Silahtaroglu, Asli N.; Nolting, Dorrit; Andersen, Lars Dyrskjøt;


    The ability to determine spatial and temporal microRNA (miRNA) accumulation at the tissue, cell and subcellular levels is essential for understanding the biological roles of miRNAs and miRNA-associated gene regulatory networks. This protocol describes a method for fast and effective detection of mi......RNAs in frozen tissue sections using fluorescence in situ hybridization (FISH). The method combines the unique miRNA recognition properties of locked nucleic acid (LNA)-modified oligonucleotide probes with FISH using the tyramide signal amplification (TSA) technology. Although both approaches have previously...... protocol can be completed within approximately 6 h and allows miRNA detection in a wide variety of animal tissue cryosections as well as in human tumor biopsies at high cellular resolution....

  11. Nucleic acid detection technology used in blood screening of blood donors%核酸检测技术在献血者血液筛查中的应用

    Institute of Scientific and Technical Information of China (English)

    梁启忠; 程玉根


    Objective To evaluate the necessity and feasibility of nucleic acid test for donors blood screening .Methods From July 1 ,2011 to December 31 ,2014 ,a total of 170 316 blood samples which were negative in enzyme-linked immunosorbent assay (ELISA)and qualified in aianine aminotransferase detection ,were selected in this study stochastically .All the samples were detected hepatitis B virus(HBV) ,hepatitis C virus(HCV) ,human immunodeficiency virus(HIV) by nucleic acid amplification technology (NAT) .NAT positive samples were reconfirmed in National Center for Clinical Laboratories(NCCL) .Results A total of 160 cases of nucleic acid reactive samples were found out ,the total response rate was 0 .09% ,The response rate of Roche nucleic acid detec-tion system was 0 .10% ,response rate of David nucleic acid detection system was 0 .08% ,there was no significant difference be-tween the two methods(P>0 .05) .In 27 cases of specimens ,14 cases were confirmed as HBV DNA positive ,no HCV RNA and HIV RNA were detected ,the confirmed positive rate was 51 .85% .There were 2 samples detected by chemiluminescence HBsAg reactivity .Conclusion ELISA screening of blood donors has missing phenomenon ,nucleic acid detection method could be used as an effective supplement of the ELISA ,could improve the safety of blood for clinical use ,detection sensitivity is better than ELISA .%目的:探讨核酸检测技术应用于献血者血液筛查的必要性和可行性。方法对2011年7月1日至2014年12月31日经ELISA检测均合格的献血者标本170316份,再采用核酸检测技术联合检测乙型肝炎病毒、丙型肝炎病毒、人类免疫缺陷病毒核酸,对筛查呈反应性的部分标本再送卫计委临床检验中心进行确证。结果共筛查出160份核酸反应性标本,总反应性率为0.09%,其中罗氏核酸检测系统反应性率为0.10%,达安核酸检测系统反应性率为0.08%,两者差异无统计学意义( P>0.05

  12. Effect of farming system and cheesemaking technology on the physicochemical characteristics, fatty acid profile, and sensory properties of Caciocavallo Palermitano cheese. (United States)

    Bonanno, A; Tornambè, G; Bellina, V; De Pasquale, C; Mazza, F; Maniaci, G; Di Grigoli, A


    Caciocavallo Palermitano is a typical stretched-curd cheese that has been produced over the centuries in Sicily according to traditional cheesemaking technology and using raw milk from autochthonous cow breeds reared at pasture. The objective of this experiment was to evaluate the effects of the farming system and processing technology on the characteristics of Caciocavallo Palermitano cheese, with particular regard to the fatty acid profile. The farming system was either extensive, using autochthonous cows fed a pasture-based diet, or intensive, with specialized dairy cow breeds fed mainly hay and concentrate. The cheese-processing technology was either artisanal, using traditional wooden tools and endemic lactic bacteria, or advanced, using modern steel equipment and selected lactic bacteria. Twelve Caciocavallo Palermitano cheeses, 3 from each of the 4 experimental theses (2 farming systems × 2 cheesemaking technologies), were obtained and aged for 1, 30, 60, and 120 d. Milk of origin and cheeses were analyzed for the main chemical and rheological parameters. Fatty acids were methylated in lyophilized cheese and analyzed by gas chromatography. Sensory analysis was carried out by trained panelists. The PROC GLM of SAS 9.1.2 (SAS Institute Inc., Cary, NY) was used for the statistical analysis. The physical, chemical, and sensory characteristics of Caciocavallo Palermitano cheese were influenced more by the farming system than by the cheesemaking technology. Compared with cheese produced through intensive farming, cheese from extensive farming was richer in polyunsaturated, n-3, and odd- and branched-chain fatty acids, as well as in conjugated linoleic acid (cis-9,trans-11 C18:2), with accompanying improved human health benefits. The cheesemaking technology produced variation in the evolution of proteolysis during aging, due presumably to the different active microflora, which influenced the sensory profile of the resulting cheese. Indeed, cheese produced by

  13. Flux variability scanning based on enforced objective flux for identifying gene amplification targets

    Directory of Open Access Journals (Sweden)

    Park Jong


    Full Text Available Abstract Background In order to reduce time and efforts to develop microbial strains with better capability of producing desired bioproducts, genome-scale metabolic simulations have proven useful in identifying gene knockout and amplification targets. Constraints-based flux analysis has successfully been employed for such simulation, but is limited in its ability to properly describe the complex nature of biological systems. Gene knockout simulations are relatively straightforward to implement, simply by constraining the flux values of the target reaction to zero, but the identification of reliable gene amplification targets is rather difficult. Here, we report a new algorithm which incorporates physiological data into a model to improve the model’s prediction capabilities and to capitalize on the relationships between genes and metabolic fluxes. Results We developed an algorithm, flux variability scanning based on enforced objective flux (FVSEOF with grouping reaction (GR constraints, in an effort to identify gene amplification targets by considering reactions that co-carry flux values based on physiological omics data via “GR constraints”. This method scans changes in the variabilities of metabolic fluxes in response to an artificially enforced objective flux of product formation. The gene amplification targets predicted using this method were validated by comparing the predicted effects with the previous experimental results obtained for the production of shikimic acid and putrescine in Escherichia coli. Moreover, new gene amplification targets for further enhancing putrescine production were validated through experiments involving the overexpression of each identified targeted gene under condition-controlled batch cultivation. Conclusions FVSEOF with GR constraints allows identification of gene amplification targets for metabolic engineering of microbial strains in order to enhance the production of desired bioproducts. The algorithm

  14. Some Technological Properties of Lactic Acid Bacteria Isolated from Dahi and Datshi, Naturally Fermented Milk Products of Bhutan (United States)

    Shangpliang, H. N. J.; Sharma, Sharmila; Rai, Ranjita; Tamang, Jyoti P.


    Dahi and datshi are common naturally fermented milk (NFM) products of Bhutan. Population of lactic acid bacteria (LAB) in dahi (pH 3.7) and datshi (pH 5.2) was 1.4 × 107 and 3.9 × 108 cfu/ml, respectively. Based on 16S rRNA gene sequencing isolates of LAB from dahi and datshi were identified as Enterococcus faecalis, E. faecium, Lactococcus lactis subsp. lactis. LAB strains were tested for some technological properties. All LAB strains except E. faecalis CH2:17 caused coagulation of milk at both 30°C for 48 h. Only E. faecium DH4:05 strain was resistant to pH 3. No significant difference (P > 0.05) of viable counts was observed in MRS broth with and without lysozyme. All LAB strains grew well in 0.3% bile showing their ability to tolerate bile salt. None of the LAB strains showed >70% hydrophobicity. This study, being the first of its microbiological analysis of the NFM of Bhutan, has opened up to an extent of research work that gives a new insight to the products. PMID:28203227

  15. Modifying the fatty acid profile of dairy products through feedlot technology lowers plasma cholesterol of humans consuming the products. (United States)

    Noakes, M; Nestel, P J; Clifton, P M


    Intake of milk and butter has been clearly associated with higher coronary heart disease rates in different countries and this is likely to be mediated by the hypercholesterolemic effect of dairy fat. Fat-modified dairy products are an innovation involving a technology in which protected unsaturated lipids are fed to ruminants resulting in milk and tissue lipids with reduced saturated fatty acids. We examined the impact of these novel dairy fats on plasma lipids in a human dietary trial. Thirty-three men and women participated in an 8-wk randomized crossover trial comparing fat-modified with conventional dairy products. The trial consisted of a 2-wk low-fat baseline period followed by two 3-wk intervention phases. During the test periods, the fat-modified products resulted in a significant 0.28-mmol/L (4.3%) lowering of total cholesterol (P dairy products, if applied to populations typical of developed Western countries, represents a potential strategy to lower the risk of coronary heart disease without any appreciable change in customary eating patterns.

  16. Gravito-magnetic amplification in cosmology

    CERN Document Server

    Tsagas, Christos G


    Magnetic fields interact with gravitational waves in various ways. We consider the coupling between the Weyl and the Maxwell fields in cosmology and study the effects of the former on the latter. The approach is fully analytical and the results are gauge-invariant. We show that the nature and the outcome of the gravito-magnetic interaction depends on the electric properties of the cosmic medium. When the conductivity is high, gravitational waves reduce the standard (adiabatic) decay rate of the B-field, leading to its superadiabatic amplification. In poorly conductive environments, on the other hand, Weyl-curvature distortions can result into the resonant amplification of large-scale cosmological magnetic fields. Driven by the gravitational waves, these B-fields oscillate with an amplitude that is found to diverge when the wavelengths of the two sources coincide. We present technical and physical aspects of the gravito-magnetic interaction and discuss its potential implications.

  17. Amplification of postwildfire peak flow by debris (United States)

    Kean, J. W.; McGuire, L. A.; Rengers, F. K.; Smith, J. B.; Staley, D. M.


    In burned steeplands, the peak depth and discharge of postwildfire runoff can substantially increase from the addition of debris. Yet methods to estimate the increase over water flow are lacking. We quantified the potential amplification of peak stage and discharge using video observations of postwildfire runoff, compiled data on postwildfire peak flow (Qp), and a physically based model. Comparison of flood and debris flow data with similar distributions in drainage area (A) and rainfall intensity (I) showed that the median runoff coefficient (C = Qp/AI) of debris flows is 50 times greater than that of floods. The striking increase in Qp can be explained using a fully predictive model that describes the additional flow resistance caused by the emergence of coarse-grained surge fronts. The model provides estimates of the amplification of peak depth, discharge, and shear stress needed for assessing postwildfire hazards and constraining models of bedrock incision.

  18. Internal entanglement amplification by external interactions



    We propose a scheme to control the level of entanglement between two fixed spin-1/2 systems by interaction with a third particle. For specific designs, entanglement is shown to be "pumped" into the system from the surroundings even when the spin-spin interaction within the system is small or nonexistent. The effect of the external particle on the system is introduced by including a dynamic spinor in the Hamiltonian. Controlled amplification of the internal entanglement to its maximum value is...


    Boese, B. J.; Corbino, K.; Breaker, R. R.


    We sought to create new cellulose-binding RNA aptamers for use as modular components in the engineering of complex functional nucleic acids. We designed our in vitro selection strategy to incorporate self-sustained sequence replication (3SR), which is an isothermal nucleic acid amplification protocol that allows for the rapid amplification of RNAs with little manipulation. The best performing aptamer representative was chosen for reselection and further optimization. The aptamer exhibits robust affinity for cellulose in both the powdered and paper form, but did not show any significant affinity for closely related polysaccharides. The minimal cellulose-binding RNA aptamer also can be grafted onto other RNAs to permit the isolation of RNAs from complex biochemical mixtures via cellulose affinity chromatography. This was demonstrated by fusing the aptamer to a glmS ribozyme sequence, and selectively eluting ribozyme cleavage products from cellulose using the glucosamine 6-phosphate to activate glmS ribozyme function. PMID:18696364

  20. Application of internal control in nucleic acid amplification technology in blood screening on system evaluation%血液筛查核酸检测内标在系统评价的应用分析

    Institute of Scientific and Technical Information of China (English)

    陈少彬; 何子毅; 陈庆恺; 王庆; 余霖; 陈静文; 邹姣丽; 苏婉兰; 邓妙玲


    目的 分析COBASs201核酸血筛系统内标(internal control,IC)检测结果差异的影响因素,探讨利用IC的Ct值评价检测系统的稳定性.方法 随机抽取本室2015年1-10月共131批次的核酸检测的IC结果,按不同仪器(A、B仪器)、试剂批号(批号1、批号2和批号3)和标本类型(MPC、HIV-1O、HIV-2、NC和献血者标本)分别分成3组,分析各组间及组内各IC的Ct均值的差异.结果 本室测定IC的Ct均值的95%参考范围为35.18-37.34;95%置信区间为[36.21,36.30];A、B仪器间以及3个试剂批号间的IC结果差异均有统计学意义(P<0.05),其中A仪器IC均值小于B仪器(P<0.05),批号2 IC的Ct均值分别小于批号1和批号3(P<0.05);不同试剂批号间IC结果差异(F =94.487,P<0.05)明显高于不同仪器检测的IC结果差异(F=16.609,P<0.05);此外,5种不同标本类型的IC也存在显著差异(P<0.05),其中标本组和NC组IC的Ct值分别大干MPC组、HIV-1O组和HIV-2组(P<0.05),MPC组、HIV-IO组和HIV-2组间的IC差异无统计学意义(P>0.05),NC组和标本组的IC值差异不显著(P>0.05).结论 不同试剂批号和仪器能引起IC值检测差异,做好试剂使用前性能确认和仪器定期维护校准是保障核酸检测结果准确稳定的有效方法;监测IC变化可作为实验室内部质量控制的评价指标.

  1. Analysis of nucleic acid amplification technology in different screening modes%核酸检测技术在不同血液安全筛查模式的应用分析

    Institute of Scientific and Technical Information of China (English)

    何子毅; 余霖; 王庆; 陈少彬; 刘仁强; 车嘉琳


    目的 比较核酸检测技术(NAT)在无偿献血不同血液安全筛查模式下阳性反应率.方法 在2010年1月1日-2013年8月31日期间,采用2遍ELISA检测,无反应性样本采用CobasTaqsceen MPX Test进行1遍NAT;2013年9月1日-2014年9月29日期间,采用1遍ELISA检测,无反应性样本采用CobasTaqseeen MPX Test进行1遍NAT;2014年9月29日-2015年8月31日期间,采用1遍ELISA检测,无反应性样本采用CobasTaqsceen MPXTest v2.0(MPX v2.0)进行1遍NAT.对NAT混检阳性pool采用MPX v2.0拆分单检,并鉴别病毒种类;对ELISA检测抗-HIV无反应性、HIV RNA有反应性的献血者定期进行追踪分析,观察有无血清学转换,以确定感染状态.结果 3个阶段共完成NAT标本422 667份,混检阳性898pools,阳性率0.21%,其中HBVDNA混检阳性率为0.209%(893/422 667),HCVRNA混检阳性1例(1/422 667),HIVRNA混检阳性4例(4/422 667);拆分单检总阳性率为0.126% (551/422 667),拆分阳性率为61.35%(551/898),拆分后单检HBVDNA阳性545例,HCVRNA阳性2例,HIVRNA阳性4例.对HIVRNA阳性样本进行定期追踪分析,4例献血者均在献血后3个月内发生血清学阳转,确定均为窗口期感染HIV.3个阶段采用不同的检测模式,NAT总阳性反应率无显著性差异;拆分单检阳性反应率Ⅲ阶段高于Ⅰ阶段(P<0.05).结论 NAT检测的总阳性反应率与检测模式无关;应用NAT可降低输血风险,尤其对HBV窗口期感染的阳性检出率较高.

  2. Spellbinding and crooning: sound amplification, radio, and political rhetoric in international comparative perspective, 1900-1945. (United States)

    Wijfjes, Huub


    This article researches in an interdisciplinary way the relationship of sound technology and political culture at the beginning of the twentieth century. It sketches the different strategies that politicians--Franklin D. Roosevelt, Adolf Hitler, Winston Churchill, and Dutch prime minister Hendrikus Colijn--found for the challenges that sound amplification and radio created for their rhetoric and presentation. Taking their different political styles into account, the article demonstrates that the interconnected technologies of sound amplification and radio forced a transition from a spellbinding style based on atmosphere and pathos in a virtual environment to "political crooning" that created artificial intimacy in despatialized simultaneity. Roosevelt and Colijn created the best examples of this political crooning, while Churchill and Hitler encountered problems in this respect. Churchill's radio successes profited from the special circumstances during the first period of World War II. Hitler's speeches were integrated into a radio regime trying to shape, with dictatorial powers, a national socialistic community of listeners.

  3. Improvement of Fatty Acid Profile and Studio of Rheological and Technological Characteristics in Breads Supplemented with Flaxseed, Soybean, and Wheat Bran Flours

    Directory of Open Access Journals (Sweden)

    Mariana B. Osuna


    Full Text Available Functional breads constitute an interesting alternative as vehicle of new essential fatty acids sources. The aim of this study was to improve the fatty acids (FA profile of bakery products, producing breads with low saturated fatty acid (SFA content and with high polyunsaturated fatty acid (PUFA content, through partial substitution of wheat flour by other ingredients (soy flour, flax flour, and wheat bran and to analyze the effect of this change on the technological, rheological, and sensorial characteristics of breads. Flaxseed flour (FF, soybeans flour (SF, or wheat bran (WB was used to replace 50, 100, and 150 g kg−1 of wheat flour (WF in breads. FF or SF produced a decrease in monounsaturated and SFA and an increase of PUFA in these breads. Furthermore, breads replaced with FF presented considerable increase in the content of n3 FA, while, SF or WB contributed to rise of linoleic and oleic FA, respectively. The substitution percentage increase of FF, SF, or WB to formulation produced changes in the colour, rheological, textural, and technological characteristics of breads. This replacement resulted in improved lipid profile, being breads with 50 g kg−1 SF, the better acceptance, baking features, and enhanced fatty acid profile.

  4. Improvement of Fatty Acid Profile and Studio of Rheological and Technological Characteristics in Breads Supplemented with Flaxseed, Soybean, and Wheat Bran Flours (United States)

    Osuna, Mariana B.; Judis, María A.; Romero, Ana M.; Avallone, Carmen M.; Bertola, Nora C.


    Functional breads constitute an interesting alternative as vehicle of new essential fatty acids sources. The aim of this study was to improve the fatty acids (FA) profile of bakery products, producing breads with low saturated fatty acid (SFA) content and with high polyunsaturated fatty acid (PUFA) content, through partial substitution of wheat flour by other ingredients (soy flour, flax flour, and wheat bran) and to analyze the effect of this change on the technological, rheological, and sensorial characteristics of breads. Flaxseed flour (FF), soybeans flour (SF), or wheat bran (WB) was used to replace 50, 100, and 150 g kg−1 of wheat flour (WF) in breads. FF or SF produced a decrease in monounsaturated and SFA and an increase of PUFA in these breads. Furthermore, breads replaced with FF presented considerable increase in the content of n3 FA, while, SF or WB contributed to rise of linoleic and oleic FA, respectively. The substitution percentage increase of FF, SF, or WB to formulation produced changes in the colour, rheological, textural, and technological characteristics of breads. This replacement resulted in improved lipid profile, being breads with 50 g kg−1 SF, the better acceptance, baking features, and enhanced fatty acid profile. PMID:25478592

  5. Complementary RNA amplification methods enhance microarray identification of transcripts expressed in the C. elegans nervous system

    Directory of Open Access Journals (Sweden)

    Levy Shawn


    Full Text Available Abstract Background DNA microarrays provide a powerful method for global analysis of gene expression. The application of this technology to specific cell types and tissues, however, is typically limited by small amounts of available mRNA, thereby necessitating amplification. Here we compare microarray results obtained with two different methods of RNA amplification to profile gene expression in the C. elegans larval nervous system. Results We used the mRNA-tagging strategy to isolate transcripts specifically from C. elegans larval neurons. The WT-Ovation Pico System (WT-Pico was used to amplify 2 ng of pan-neural RNA to produce labeled cDNA for microarray analysis. These WT-Pico-derived data were compared to microarray results obtained with a labeled aRNA target generated by two rounds of In Vitro Transcription (IVT of 25 ng of pan-neural RNA. WT-Pico results in a higher fraction of present calls than IVT, a finding consistent with the proposal that DNA-DNA hybridization results in lower mismatch signals than the RNA-DNA heteroduplexes produced by IVT amplification. Microarray data sets from these samples were compared to a reference profile of all larval cells to identify transcripts with elevated expression in neurons. These results were validated by the high proportion of known neuron-expressed genes detected in these profiles and by promoter-GFP constructs for previously uncharacterized genes in these data sets. Together, the IVT and WT-Pico methods identified 2,173 unique neuron-enriched transcripts. Only about half of these transcripts (1,044, however, are detected as enriched by both IVT and WT-Pico amplification. Conclusion We show that two different methods of RNA amplification, IVT and WT-Pico, produce valid microarray profiles of gene expression in the C. elegans larval nervous system with a low rate of false positives. However, our results also show that each method of RNA amplification detects a unique subset of bona fide neural

  6. 蓖麻油脂肪酸镁生产技术研究与应用%Production Technology Research and Application of Magnesium Castor Oil Fatty Acid

    Institute of Scientific and Technical Information of China (English)

    王恩; 许广秀


    In this thesis,the production technology of Magnesium castor oil fatty acid was studied,saponification reaction,double decomposition reaction,spin-drying,drying processes,etc were studied specially to determine the appropriate technology specification.%研究了蓖麻油脂肪酸镁的生产技术,对生产过程中的皂化反应、复分解反应、甩干、烘干工序等进行了专题研究,确定了相应的工艺技术指标.

  7. Advances in technologies for hydrogenation of acetic acid and acetates to ethanol%醋酸和醋酸酯加氢制乙醇技术进展

    Institute of Scientific and Technical Information of China (English)

    王彪; 王熙庭; 徐国辉


      Advances in the technologies for hydrogenation of acetic acid and acetates to ethanol were reviewed. The tow kinds of technology had their advantages and disadvantages, and both should be further improved and developed.%  综述了醋酸直接加氢制乙醇技术与醋酸酯化加氢制乙醇技术的研究进展,指出两种技术各有优缺点,都应进一步完善和发展。

  8. Technological challenges to assess n-3 polyunsaturated fatty acids from marine oils for nutritional and pharmacological use


    A. Valenzuela; Nieto, S.; Uauy, R


    The benefits ascribed to marine oils rich in n-3 polyunsaturated fatty acids has led to efforts to improve the chemical and organoleptic characteristics of these oils and to develop procedures for the obtention of pure or highly concentrated fractions of some n-3 fatty acids. Two n-3 fatty acids are of main interest; the eicosapentaenoic acid (C20:5, EPA) and the docosahexaenoic acid (022:6, DHA). The present review is referred to the identification of the main sources of marine n-3 polyunsat...

  9. [Technological advances in single-cell genomic analyses]. (United States)

    Pan, Xing-Hua; Zhu, Hai-Ying; Marjani, Sadie L


    The technological progress of the genomics has transformed life science research. The main objectives of genomics are sequencing of new genomes and genome-wide identification of the function and the interaction of genes and their products. The recently developed second generation or next generation sequencing platforms and DNA microarray technology are immensely important and powerful tools for functional genomic analyses. However, their application is limited by the requirement of sufficient amounts of high quality nucleic acid samples. Therefore, when only a single cell or a very small number of cells are available or are preferred, the whole genomic sequencing or functional genomic objectives cannot be achieved conventionally and require a robust amplification method. This review highlights DNA amplification technologies and summarizes the strategies currently utilized for whole genome sequencing of a single cell, with specific focus on studies investigating microorganisms; An outline for targeted re-sequencing enabling the analysis of larger genomes is also provided. Furthermore, the review presents the emerging functional genomic applications using next-generation sequencing or microarray analysis to examine genome-wide transcriptional profile, chromatin modification and other types of protein-DNA binding profile, and CpG methylation mapping in a single cell or a very low quantity of cells. The nature of these technologies and their prospects are also addressed.

  10. Ultrasensitive electrochemical aptasensor for ochratoxin A based on two-level cascaded signal amplification strategy. (United States)

    Yang, Xingwang; Qian, Jing; Jiang, Ling; Yan, Yuting; Wang, Kan; Liu, Qian; Wang, Kun


    Ochratoxin A (OTA) has a number of toxic effects to both humans and animals, so developing sensitive detection method is of great importance. Herein, we describe an ultrasensitive electrochemical aptasensor for OTA based on the two-level cascaded signal amplification strategy with methylene blue (MB) as a redox indicator. In this method, capture DNA, aptamers, and reporter DNA functionalized-gold nanoparticles (GNPs) were immobilized on the electrode accordingly, where GNPs were used as the first-level signal enhancer. To receive the more sensitive response, a larger number of guanine (G)-rich DNA was bound to the GNPs' surface to provide abundant anchoring sites for MB to achieve the second-level signal amplification. By employing this novel strategy, an ~8.5 (±0.3) fold amplification in signal intensity was obtained. Afterward, OTA was added to force partial GNPs/G-rich DNA to release from the sensing interface and thus decreased the electrochemical response. An effective sensing range from 2.5pM to 2.5nM was received with an extremely low detection limit of 0.75 (±0.12) pM. This amplification strategy has the potential to be the main technology for aptamer-based electrochemical biosensor in a variety of fields.

  11. Photoacoustic imaging using lock-in amplification and pulsed fiber lasers (United States)

    Shi, Wei; Hajireza, Parsin; Zemp, Roger


    Photoacoustic (PA) imaging is a non-invasive, non-ionizing imaging technology with high optical contrast between blood and tissue, and with high sensitivity of hemoglobin concentration and oxygen saturation due to different optical absorption spectra resulting from different oxygenation of hemoglobin. Most PA imaging systems implement a nanosecond pulsed laser source as excitation source to induce PA signal, and rely on broadband amplifiers to record time-domain PA signals [1-6]. Some groups, however, have reported using modulated continuous-wave lasers as an excitation source for frequency-domain imaging [7-9]. Frequency-domain imaging offers the potential of lock-in amplification which has sensitivities as low as nV even in noise orders of magnitude higher than the signal. However, although modulated CW sources works for low cost and compact PA imaging, it does not satisfy thermal and stress confinement conditions required for optimal PA signal strength. Here, we investigate a PA methodology using pulsed fiber lasers as excitation laser source combined with lock-in amplification technology. For comparison, we also studied time-domain PA methodology. Phantom studies show that signal-to-noise ratio (SNR) obtained with frequency domain PA imaging is significantly more sensitive than that obtained using time-domain PA imaging when the laser pulse repetition rate (PRR) matches the bandwidth of ultrasound transducer. Therefore, high sensitive PA imaging technology using pulsed fiber laser sources with lock-in amplification may potentially greatly extend the depth of PA imaging.

  12. Final Report: Evaluation of Alternative Technologies for Ethylene, Caustic-Chlorine, Ethylene Oxide, Ammonia, and Terephthalic Acid

    Energy Technology Data Exchange (ETDEWEB)



    This report evaluates alternative technologies for chemicals manufacturing which may present energy efficiency improvements compared to existing technologies. It is an extension of the Chemical Bandwidth Study, which evaluates energy and exergy losses in the U.S. chemicals industry.


    Directory of Open Access Journals (Sweden)

    Lisovets U. A.


    Full Text Available The results of the study of amino acids of white table wines depending on the yeast strain, continuous contact of wine with yeast biomass and the presence of lees stirring are presented. The dynamics of amino acids, which affect wine organoleptic characteristics and the formation of wine defects, specifically, tyrosine, methionine, threonine and lysine is shown. Conducted researches made it possible to divide the amino acids into three groups depending on the carrying out the batonnage or lack of it. The first group consisted of amino acids, the concentration of which practically has not changed in the presence or lack of stirring. The second and third groups include amino acids, the concentration of which increased and decreased, respectively during batonnage. The stirring of the wine with yeast biomass facilitated to the activation of mass transfer processes between cell and medium, and the access of air lead to oxidation of some amino acids and the change of its concentration. The absence of stirring influenced to a slight increase in the concentration of such amino acids as cystine, cysteine, β-phenylalanine, serine, α-alanine, leucine and glutamic acid. The experimental data allowed to arrange amino acids in a row depending on the speed of release into the medium: ά-aminobutyric acid > glutamic acid > α-alanine > leucine

  14. Amplification Without Inversion in Semiconductor Quantum Dot (United States)

    Hajibadali, A.; Abbasian, K.; Rostami, A.

    In this paper, we have realized amplification without inversion (AWI) in quantum dot (QD). A Y-type four-level system of InxGa1-xN quantum dot has been obtained and investigated for AWI. It has been shown that, with proper setting of control fields' amplitude, we can obtain reasonable gain. With proper setting of phase difference of control fields and probe field, we can obtain considerable gain in resonant wavelength. We have designed this system by solving the Schrödinger-Poisson equations for InxGa1-xN quantum dot in GaN substrate, self-consistently.

  15. Amplification Effects and Unconventional Monetary Policies

    Directory of Open Access Journals (Sweden)



    Full Text Available Global financial crises trigger off amplification effects, which allow relatively small shocks to propagate through the whole financial system. For this reason, the range of Central banks policies is now widening beyond conventional monetary policies and lending of last resort. The aim of this paper is to establish a rule for this practice. The model is based on the formalization of funding conditions in various types of markets. We conduct a comprehensive analysis of the “unconventional monetary policies”, and especially quantify government bonds purchases by the Central bank.

  16. Amplification and characterization of eukaryotic structural genes. (United States)

    Maniatis, T; Efstratiadis, A; Sim, G K; Kafatos, F


    An approach to the study of eukaryotic structural genes which are differentially expressed during development is described. This approach involves the isolation and amplification of mRNA sequences by in vitro conversion of mRNA to double-stranded cDNA followed by molecular cloning in bacterial plasmids. This procedure provides highly specific hybridization probes that can be used to identify genes and their contiguous DNA sequences in genomic DNA, and to detect specific RNA transcripts during development. The nature of the method allows the isolation of individual mRNA sequences from a complex population of molecules at different stages of development.

  17. Development Status of High Acid Crude Oil Deacidification Technologies%国内外高酸原油脱酸发展现状

    Institute of Scientific and Technical Information of China (English)

    陈清涛; 朱玉龙; 秦一鸣; 田义斌


    近年来,随着常规原油资源日益减少和原油开采技术的提高,非常规原油的产量逐年增加。非常规原油的酸值一般较高,基本都属于高酸原油,高酸原油在加工的过程中会对设备造成严重的腐蚀,而且对石油产品的使用性能产生较大影响,因此,解决高酸原油加工问题具有重大的意义。介绍了国内外高酸原油脱酸的几种工艺,如碱洗脱酸、醇氨法脱酸、酯化脱酸、加氢法、热分解法等方法,并对各种方法进行了对比。%In recent years, with the decreasing of conventional crude oil resources and the improvement of crude oil developing technologies, unconventional crude oil production is increasing year by year. Generally, the acid number of unconventional crude oil is high. The crude oil with high acid number may cause serious corrosion to the processing equipment in the refining process. The acid number of crude oil will also impact the performance of oil products. Therefore, it is great significance to solve the processing problems of the crude oil with high acid number. In this paper, several deacidification technologies of high acid crude oil were introduced, such as alkaline wash deacidification, alcohol-ammonia deacidification, esterification deacidification, hydrogenation deacidification ,thermal decomposition deacidification and so on. At last, these oil deacidification technologies were analyzed and compared.

  18. 菜籽饼中植酸的醋酸法提取工艺及其体外抗氧化性研究%Technology of Extracting Phytic Acid with Acetic Acid and Its Antioxidant Activity in Vitro

    Institute of Scientific and Technical Information of China (English)

    汤务霞; 熊治渝; 邓颖强; 吴艳


    Rapeseed meal was the main by-products of pressing rapeseed oil and a good resource of phytic acid extraction. Using rapeseed meal as material, technology of extracting phytic acid with acetic acid and its antioxidant activity in vitro were discussed. According to the yield of phytic acid, optimal extraction conditions of phytic acid of repeseed meal by acetic acid was determined by single factor and response surface experiment, selecting extraction temperature, liquid-solid rate, acetic acid mass fraction and extraction time. The result demonstrated that the yield of phytic acid reached 20.22 mg/g on the optimal extraction conditions that extraction temperature was 65℃, liquid-solid rate was 11 : 1, acetic acid mass fraction was 0.75%, and extraction time was 75 min. With phytic acid and vitamin C as a control, by measuring the reduction ability, scavenging capacity of hydroxyl radical and DPpHo of phytic acid extract, the results showed that nhvtic acid extract had certain antinxidant aetlvitv in vitrn%菜籽饼是菜籽压榨制油的副产物,是提取植酸的良好原料。试验以菜籽饼为材料,探索采用醋酸法提取植酸的工艺条件及其体外抗氧化性。以植酸得卒为参考指标,选取提取温度、液料比、醋酸质量分数、提取时间进行单因素和响应面优化试验,得到醋酸法提取菜籽饼中植酸的工艺条件为提取温度65℃、液料比11:1、醋酸质量分数O.75%、提取时N75min。在此工艺条件下植酸得率为20.22mg/g。以标准植酸、维生素C为对照。研究植酸提取液的还原能力及对羟自由基和DPPH-的清除率,试验结果表明,植酸提取液具有一定的体外抗氧化性。

  19. Mechanism of seasonal Arctic sea ice evolution and Arctic amplification


    Kim, Kwang-Yul; Hamlington, Benjamin D.; Na, Hanna; Kim, Jinju


    Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the p...

  20. Capture and Amplification by Tailing and Switching (CATS). An ultrasensitive ligation-independent method for generation of DNA libraries for deep sequencing from picogram amounts of DNA and RNA. (United States)

    Turchinovich, Andrey; Surowy, Harald; Serva, Andrius; Zapatka, Marc; Lichter, Peter; Burwinkel, Barbara


    Massive parallel sequencing (MPS) technologies have paved the way into new areas of research including individualized medicine. However, sequencing of trace amounts of DNA or RNA still remains a major challenge, especially for degraded nucleic acids like circulating DNA. This together with high cost and time requirements impedes many important applications of MPS in medicine and fundamental science. We have established a fast, cheap and highly efficient protocol called 'Capture and Amplification by Tailing and Switching' (CATS) to directly generate ready-to-sequence libraries for MPS from nanogram and picogram quantities of both DNA and RNA. Furthermore, those DNA libraries are strand-specific, can be prepared within 2-3 h and do not require preliminary sample amplification steps. To exemplify the capacity of the technique, we have generated and sequenced DNA libraries from hundred-picogram amounts of circulating nucleic acids isolated from human blood plasma, one nanogram of mRNA-enriched total RNA from cultured cells and few nanograms of bisulfite-converted DNA. The approach for DNA library preparation from minimal and fragmented input described here will find broad application in diverse research areas such as translational medicine including therapy monitoring, prediction, prognosis and early detection of various human disorders and will permit high-throughput DNA sequencing from previously inaccessible material such as minute forensic and archeological samples.

  1. Magnetic Field Amplification in Young Galaxies

    CERN Document Server

    Schober, Jennifer; Klessen, Ralf S


    The Universe at present is highly magnetized, with fields of the order of a few 10^-5 G and coherence lengths larger than 10 kpc in typical galaxies like the Milky Way. We propose that the magnetic field was amplified to this values already during the formation and the early evolution of the galaxies. Turbulence in young galaxies is driven by accretion as well as by supernova (SN) explosions of the first generation of stars. The small-scale dynamo can convert the turbulent kinetic energy into magnetic energy and amplify very weak primordial magnetic seed fields on short timescales. The amplification takes place in two phases: in the kinematic phase the magnetic field grows exponentially, with the largest growth on the smallest non-resistive scale. In the following non-linear phase the magnetic energy is shifted towards larger scales until the dynamo saturates on the turbulent forcing scale. To describe the amplification of the magnetic field quantitatively we model the microphysics in the interstellar medium ...

  2. Experimental noiseless linear amplification using weak measurements (United States)

    Ho, Joseph; Boston, Allen; Palsson, Matthew; Pryde, Geoff


    The viability of quantum communication schemes rely on sending quantum states of light over long distances. However, transmission loss can degrade the signal strength, adding noise. Heralded noiseless amplification of a quantum signal can provide a solution by enabling longer direct transmission distances and by enabling entanglement distillation. The central idea of heralded noiseless amplification—a conditional modification of the probability distribution over photon number of an optical quantum state—is suggestive of a parallel with weak measurement: in a weak measurement, learning partial information about an observable leads to a conditional back-action of a commensurate size. Here we experimentally investigate the application of weak, or variable-strength, measurements to the task of heralded amplification, by using a quantum logic gate to weakly couple a small single-optical-mode quantum state (the signal) to an ancilla photon (the meter). The weak measurement is carried out by choosing the measurement basis of the meter photon and, by conditioning on the meter outcomes, the signal is amplified. We characterise the gain of the amplifier as a function of the measurement strength, and use interferometric methods to show that the operation preserves the coherence of the signal.

  3. Comparison of recombinase-aid amplification and traditional polymerase chain reaction in DNA methylation detection of thyroid cancer%重组酶介导扩增技术与传统聚合酶链反应技术在甲状腺癌DNA甲基化检测中的应用比较

    Institute of Scientific and Technical Information of China (English)

    廖萍; 刘茶珍; 朱佩云; 刘国星; 王文静


    Objective To find a new technology and compare it with methylation specific polymerase chain reaction (MSP) in DNA methylation detection of thyroid cancer.Methods OXTR was selected as object of study.After samples DNA were extracted and were modified,the recombinase-aid amplification(RAA) and traditional MSP were separately used to amplify the target gene OXTR which was modified with bisulfite.Results Both the two technology succeeded in amplifying unmethylated OXTR gene.RAA succeeded in amplifying the methylated gene band.Conclusions RAA is a novel isothermal amplification technology in nucleic acid amplification technologies.It could be performed at 37 ℃ with no need to initial heat denaturation at a high temperature followed by amplification at a lower temperature,and this isothermal amplification technology may successfully compete with its widely used non-isothermal predecessor (PCR) for molecular biological study and application.%目的 建立重组酶介导的核酸扩增(RAA)技术特异性检测DNA甲基化的新方法并与传统的DNA甲基化特异性PCR(MSP)方法进行比较.方法 选取OXTR基因作为目的基因,提取样品外周血基因组DNA,经亚硫酸氢盐修饰后分别以MSP和RAA技术进行特异性检测DNA甲基化实验.结果 2种技术皆能扩增出OXTR非甲基化条带,而RAA技术成功扩增OXTR甲基化条带.结论 RAA是一种新型的等温体外核酸扩增技术,实现了在37℃恒温下的核酸快速扩增,可成为替代MSP乃至其他PCR实验的新方法.

  4. Seismic Wave Amplification in 3D Alluvial Basins: 3D/1D Amplification Ratios from Fast Multipole BEM Simulations

    CERN Document Server

    Fajardo, Kristel C Meza; Chaillat, Stéphanie; Lenti, Luca


    In this work, we study seismic wave amplification in alluvial basins having 3D standard geometries through the Fast Multipole Boundary Element Method in the frequency domain. We investigate how much 3D amplification differs from the 1D (horizontal layering) case. Considering incident fields of plane harmonic waves, we examine the relationships between the amplification level and the most relevant physical parameters of the problem (impedance contrast, 3D aspect ratio, vertical and oblique incidence of plane waves). The FMBEM results show that the most important parameters for wave amplification are the impedance contrast and the so-called equivalent shape ratio. Using these two parameters, we derive simple rules to compute the fundamental frequency for various 3D basin shapes and the corresponding 3D/1D amplification factor for 5% damping. Effects on amplification due to 3D basin asymmetry are also studied and incorporated in the derived rules.

  5. Rapid detection of microbial DNA by a novel isothermal genome exponential amplification reaction (GEAR) assay. (United States)

    Prithiviraj, Jothikumar; Hill, Vincent; Jothikumar, Narayanan


    In this study we report the development of a simple target-specific isothermal nucleic acid amplification technique, termed genome exponential amplification reaction (GEAR). Escherichia coli was selected as the microbial target to demonstrate the GEAR technique as a proof of concept. The GEAR technique uses a set of four primers; in the present study these primers targeted 5 regions on the 16S rRNA gene of E. coli. The outer forward and reverse Tab primer sequences are complementary to each other at their 5' end, whereas their 3' end sequences are complementary to their respective target nucleic acid sequences. The GEAR assay was performed at a constant temperature 60 °C and monitored continuously in a real-time PCR instrument in the presence of an intercalating dye (SYTO 9). The GEAR assay enabled amplification of as few as one colony forming units of E. coli per reaction within 30 min. We also evaluated the GEAR assay for rapid identification of bacterial colonies cultured on agar media directly in the reaction without DNA extraction. Cells from E. coli colonies were picked and added directly to GEAR assay mastermix without prior DNA extraction. DNA in the cells could be amplified, yielding positive results within 15 min.

  6. First improvements in the detection and quantification of label-free nucleic acids by laser-induced breakdown spectroscopy: Application to the deoxyribonucleic acid micro-array technology

    Energy Technology Data Exchange (ETDEWEB)

    Le Meur, Julien [Laboratoire de Cancerologie Experimentale, Commissariat a l' Energie Atomique de Fontenay-aux-Roses, Direction des Sciences du Vivant, Departement de Radiobiologie et Radiopathologie, Fontenay-aux-Roses (France); Menut, Denis [Laboratoire de Reactivite des Surfaces et des Interfaces, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Wodling, Pascal [Laboratoire d' Interaction Laser-Matiere, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Salmon, Laurent [Laboratoire de Reactivite des Surfaces et des Interfaces, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Thro, Pierre-Yves [Laboratoire d' Interaction Laser-Matiere, Commissariat a l' Energie Atomique de Saclay, Direction de l' Energie Nucleaire, Departement de Physico-Chimie, Gif sur Yvette (France); Chevillard, Sylvie [Laboratoire de Cancerologie Experimentale, Commissariat a l' Energie Atomique de Fontenay-aux-Roses, Direction des Sciences du Vivant, Departement de Radiobiologie et Radiopathologie, Fontenay-aux-Roses (France); Ugolin, Nicolas [Laboratoire de Cancerologie Experimentale, Commissariat a l' Energie Atomique de Fontenay-aux-Roses, Direction des Sciences du Vivant, Departement de Radiobiologie et Radiopathologie, Fontenay-aux-Roses (France)], E-mail:


    The accurate quantification of nucleic acids is essential in many fields of modern biology and industry, and in some cases requires the use of fluorescence labeling. Yet, in addition to standardization problems and quantification reproducibility, labeling can modify the physicochemical properties of molecules or affect their stability. To address these limitations, we have developed a novel method to detect and quantify label-free nucleic acids. This method is based on stoichiometric proportioning of phosphorus in the nucleic acid skeleton, using laser-induced breakdown spectroscopy, and a specific statistical analysis, which indicates the error probability for each measurement. The results obtained appear to be quantitative, with a limit of detection of 10{sup 5} nucleotides/{mu}m{sup 2} (i.e. 2 x 10{sup 13} phosphorus atoms/cm{sup 2}). Initial micro-array analysis has given very encouraging results, which point to new ways of quantifying hybridized nucleic acids. This is essential when comparing molecules of different sequences, which is presently very difficult with fluorescence labeling.

  7. Allele-specific amplification in cancer revealed by SNP array analysis.

    Directory of Open Access Journals (Sweden)

    Thomas LaFramboise


    Full Text Available Amplification, deletion, and loss of heterozygosity of genomic DNA are hallmarks of cancer. In recent years a variety of studies have emerged measuring total chromosomal copy number at increasingly high resolution. Similarly, loss-of-heterozygosity events have been finely mapped using high-throughput genotyping technologies. We have developed a probe-level allele-specific quantitation procedure that extracts both copy number and allelotype information from single nucleotide polymorphism (SNP array data to arrive at allele-specific copy number across the genome. Our approach applies an expectation-maximization algorithm to a model derived from a novel classification of SNP array probes. This method is the first to our knowledge that is able to (a determine the generalized genotype of aberrant samples at each SNP site (e.g., CCCCT at an amplified site, and (b infer the copy number of each parental chromosome across the genome. With this method, we are able to determine not just where amplifications and deletions occur, but also the haplotype of the region being amplified or deleted. The merit of our model and general approach is demonstrated by very precise genotyping of normal samples, and our allele-specific copy number inferences are validated using PCR experiments. Applying our method to a collection of lung cancer samples, we are able to conclude that amplification is essentially monoallelic, as would be expected under the mechanisms currently believed responsible for gene amplification. This suggests that a specific parental chromosome may be targeted for amplification, whether because of germ line or somatic variation. An R software package containing the methods described in this paper is freely available at


    Directory of Open Access Journals (Sweden)

    D. A. Stepanenko


    Full Text Available The paper contains a theoretical underpinning on creation of ultrasonic vibration concentrators based on annular elastic elements with non-circular (ellipse-like eccentric shape of internal contour. Shape of internal contour in polar coordinates is described by Fourier series relative to angular coordinate that consists of a constant term and first and second harmonics. An effect of geometric parameters of the concentrator on amplification factor and natural vibration frequencies has been investigated with the help of a finite element method. The paper reveals the possibility to control an amplification factor of annular concentrators while varying eccentricity of internal contour and mean value of cross-section thickness. The amplification factor satisfies a condition K < N, where N is thickness ratio of amplifier input and output sections, and it is decreasing with increase of vibration mode order. The similar condition has been satisfied for conical bar concentrator with the difference that in the case of bar concentrators an amplification is ensured due to variation of diameter and N will represent ratio of diameters. It has been proved that modification of internal contour shape makes it possible to carry out a wide-band tuning of natural frequencies of concentrator vibrations without alteration of its overall dimensions and substantial change of amplification factor, which is important for frequency matching of the concentrator and ultrasonic vibratory system. Advantages of the proposed concentrators include simplicity of design and manufacturing, small overall dimensions, possibility for natural frequency tuning by means of static load variation. The developed concentrators can find their application in ultrasonic devices and instruments for technological and medical purposes.

  9. Compared the New Molecular Method for Rapid Detection of Avian Leukemia Virus by Using Denaturing High Performance Liquid Chromatography Combined with Nucleic Acid Amplification and Real-time PCR%PCR结合变性高效液相色谱法与荧光定量PCR法在检测禽白血病中的比较与应用

    Institute of Scientific and Technical Information of China (English)

    孙涛; 张太翔; 徐彪; 梁成珠; 朱来华; 岳志芹


    Compared the new molecular method for rapid detection of avian leukemia virus by using denaturing high performance liquid chromatography(DHPLC) combined with nucleic acid amplification and Real-time PCR in this study. According to the sequence of pol gene of ALV, one pair of primers and the TaqMan probe were designed by using Primer Premier 5. 0. The PCR fragment which was amplified by the primers were analysised by DHPLC and the results of Real-time PCR by the primers and the TaqMan probe. They all compared to normal chicken embryo allantoic fluid, duck plague virus(DPV),infectious bronchitis virus(IBV) ,goose parvovirus(GPV) ,avian influenza virus(H5Nl AIV),Newcastle disease virus(NDV), infectious bursal disease virus (IBDV) ,EDSV. There were tested to confirm the specificity of the PCR-DHPLC assay and no positive absorption peaks occurred. The detection limit of ALV AV228 by PCR-DHPLC was 3 pg,10 fold iower than the ordinary Realtime PCR. The results of detcting organ samples from the chickens were tested by PCR-DHPLC and Real-time PCR,showing 100% agreement.%本研究旨在比较PCR结合变性高效液相色谱技术(PCR-DHPLC)与荧光定量PCR (Real-time PCR)两种方法在检测禽白血病中的应用.根据禽白血病pol基因序列,设计1对引物和1条探针,利用引物进行禽白血病模板的RT-PCR扩增,产物经变性高效液相色谱上样处理;利用引物及探针进行荧光定量PCR扩增,结果与PCR-DHPLC进行比对.两种方法同时用正常鸡胚尿囊液、鸭瘟病毒、传染性支气管炎病毒、鹅细小病毒、H5N1亚型禽流感病毒、新城疫病毒、传染性法氏囊病毒、减蛋综合症病毒做特异性检测;以稀释成不同梯度的AV228毒株核酸做敏感性检测.试验结果表明PCR-DHPLC方法只对禽白血病病原有阳性扩增的吸收峰,Real-time PCR也只对禽白血病病原有阳性扩增,两法均对其他禽源病毒核酸无特异性扩增;PCR-DHPLC与Real-time PCR法

  10. Amplification of Chirality through Self-Replication of Micellar Aggregates in Water

    KAUST Repository

    Bukhriakov, Konstantin


    We describe a system in which the self-replication of micellar aggregates results in a spontaneous amplification of chirality in the reaction products. In this system, amphiphiles are synthesized from two "clickable" fragments: a water-soluble "head" and a hydrophobic "tail". Under biphasic conditions, the reaction is autocatalytic, as aggregates facilitate the transfer of hydrophobic molecules to the aqueous phase. When chiral, partially enantioenriched surfactant heads are used, a strong nonlinear induction of chirality in the reaction products is observed. Preseeding the reaction mixture with an amphiphile of one chirality results in the amplification of this product and therefore information transfer between generations of self-replicating aggregates. Because our amphiphiles are capable of catalysis, information transfer, and self-assembly into bounded structures, they present a plausible model for prenucleic acid "lipid world" entities. © 2015 American Chemical Society.

  11. Optofluidic analysis system for amplification-free, direct detection of Ebola infection (United States)

    Cai, H.; Parks, J. W.; Wall, T. A.; Stott, M. A.; Stambaugh, A.; Alfson, K.; Griffiths, A.; Mathies, R. A.; Carrion, R.; Patterson, J. L.; Hawkins, A. R.; Schmidt, H.


    The massive outbreak of highly lethal Ebola hemorrhagic fever in West Africa illustrates the urgent need for diagnostic instruments that can identify and quantify infections rapidly, accurately, and with low complexity. Here, we report on-chip sample preparation, amplification-free detection and quantification of Ebola virus on clinical samples using hybrid optofluidic integration. Sample preparation and target preconcentration are implemented on a PDMS-based microfluidic chip (automaton), followed by single nucleic acid fluorescence detection in liquid-core optical waveguides on a silicon chip in under ten minutes. We demonstrate excellent specificity, a limit of detection of 0.2 pfu/mL and a dynamic range of thirteen orders of magnitude, far outperforming other amplification-free methods. This chip-scale approach and reduced complexity compared to gold standard RT-PCR methods is ideal for portable instruments that can provide immediate diagnosis and continued monitoring of infectious diseases at the point-of-care.

  12. 多重连接依赖式探针扩增技术在α地中海贫血基因诊断与产前诊断中的应用%The application of multiplex ligation-dependent probe amplification technology in diagnosis and prenatal diagnosis of α-thalassemia

    Institute of Scientific and Technical Information of China (English)

    陈亚军; 杨学煌; 曾宪琪; 乔伶俐


    Objective To investigate the multiplex ligation-dependent probe amplification (MLPA) technology in the detection of gene deletion and prenatal diagnosis of α-thalassaemia.Methods Phenotypes were analyzed by whole blood cell counting and hemoglobin component detection of peripheral blood samples from the subjects.The gene deletions and point mutations of α-thalassaemia were detected with regular gap-PCR and reverse dot blot (RDB) method.At last,the MLPA method was applied for detection of α-globin gene deletion.All the prenatal diagnosis samples were detected with both gap-PCR and MLPA method.Results α-thalassaemia phenotype was found in 75 samples from 1256 (628 couples) peripheral blood samples for pre-pregnancy or prenatal thalassemia gene screening.Among them,71 samples carrying α-gene mutations and consistent with phenotypes were detected by routine methods.Inthe other 3 samples with no α-gene mutations detected and 1 sample with HbH phenotype but genotype of-α42/αα were analyzed by MLPA and found each one samples of whole α-globin gene cluster deletion,respectively.Seventeen high risk couples were screened.Among the 17 prenatal diagnosis samples,2 villus samples contaminated by exogenous DNA were confirmed by MLPA method.Conclusions MLPA is an effective complement for α-thalassaemia gene deletion detection.The molecular diagnosis strategy and process of gap-PCR combined with MLPA for α-thalassaemia gene deletion detection can prevent the missing of gene deletion,and false-positive or false-negative misdiagnosis of α-thalassaemia in prenatal diagnosis.%目的 探讨多重连接依赖式探针扩增(M LPA)技术在α地中海贫血(地贫)基因缺失检测及产前诊断中的应用.方法 采用全血细胞计数和血红蛋白成分检测对受检者外周血标本进行表型分析,采用常规跨越裂点PCR(gap-PCR)技术及反向斑点杂交(RDB)法检测α地贫基因缺失及点突变,采用MLPA技术检测α珠蛋白基因缺失;产前

  13. 乙醇酸生产技术的研究进展%The Research Progress of Glycolic Acid Production Technology

    Institute of Scientific and Technical Information of China (English)

    黄燕; 梁朝林


      Several existing methods of industrial production of glycolic acid ,chloroacetic acid hydrolysis ,hydroxy acetonitrile hydrolysis , formaldehyde carbonylation ,oxalic acid method ,could produce glycolic acid but under safety and environmental requirements .The research direction of glycolic acid production technology was analyzed comprehensively ,such as glyoxal oxidation ,formaldehyde and formic acid or carboxylic acid methyl ester coupling method ,hydrogenation of dimethyl oxalate ,glycol selective oxidation ,and microbiological method . Finally ,the best development direction of glycolic should be glycol selective oxidation .%  首先概述现有的几种工业生产乙醇酸的方法,即氯乙酸水解法、羟基乙氰水解法、甲醛羰基化法、草酸电解法等,虽然能生产乙醇酸,但不符合安全环保理念;综合分析了当前改进乙醇酸生产技术路线的研究方向,如乙二醛氧化法、甲醛与甲酸或甲酸甲酯偶联法、草酸二甲酯加氢法、乙二醇选择性氧化法、微生物法;最后指出,乙醇酸工业生产的最佳发展方向,应当是以乙二醇为原料选择性氧化生产乙醇酸。

  14. Broadening and Amplification of an Infrared Femtosecond Pulse for Optical Parametric Chirped-Pulse Amplification

    Institute of Scientific and Technical Information of China (English)

    WANG He-Lin; YANG Ai-Jun; LENG Yu-Xin


    A high-average-power diode-pumped narrowband regenerative chirped pulse amplifier is developed using the thin-rod Nd:YAG laser architecture for optical parametric chirped-pulse amplification (OPCPA).The effect of the etalons on the amplified pulse in the regenerative cavity is studied experimentally and theoretically.By inserting glass etalons of thickness 1 mm and 5 mm into the regenerative cavity,the pre-stretching pulse from an (O)ffner stretcher is further broadened to above 200ps,which matches the amplification windows of the signal pulses in OPCPA and is suitable for use as a pump source in the OPCPA system.The bandwidth of the amplified pulse is 1.5 nm,and an output energy of 2mJ is achieved at a repetition rate of 10 Hz.Optical parametric chirped pulse amplification (OPCPA)[1-4] has attracted a great deal of attention as the most promising technique for generating ultrashort ultrahigh-peak-power laser pulses because of its very broad gain bandwidth,negligible thermal load on the nonlinear crystal,and extremely high singlepass gain as compared to amplifiers based on laser gain media.For efficient amplification and high fidelity of dispersion compensation in OPCPA,a femtosecond seed pulse is first stretched to several tens of picoseconds with a bulk grating stretcher or a fiber stretcher.%A high-average-power diode-pumped narrowband regenerative chirped pulse amplifier is developed using the thin-rod Nd:YAG laser architecture for optical parametric chirped-pulse amplification (OPCPA). The effect of the etalons on the amplified pulse in the regenerative cavity is studied experimentally and theoretically. By inserting glass etalons of thickness 1 mm and 5 mm into the regenerative cavity, the pre-stretching pulse from an (O)finer stretcher is further broadened to above 200 ps, which matches the amplification windows of the signal pulses in OPCPA and is suitable for use as a pump source in the OPCPA system. The bandwidth of the amplified pulse is 1.5 nm, and an

  15. Development of internal amplification controls for DNA profiling with the AmpFℓSTR(®) SGM Plus(®) kit. (United States)

    Zahra, Nathalie; Hadi, Sibte; Smith, Judith A; Iyengar, Arati; Goodwin, William


    DNA extracted from forensic samples can be degraded and also contain co-extracted contaminants that inhibit PCR. The effects of DNA degradation and PCR inhibition are often indistinguishable when examining a DNA profile. Two internal amplification controls (IACs) were developed to improve quality control of PCR using the AmpFℓSTR® SGM Plus® kit. The co-amplification of these controls with DNA samples was used to monitor amplification efficiency and detect PCR inhibitors. IAC fragments of 90 and 410 bp (IAC₉₀ and IAC₄₁₀) were generated from the plasmid pBR322 using tailed primers and then amplified with ROX-labelled primers. Co-amplification of IAC₉₀ and IAC₄₁₀ was performed with varying amounts of template DNA, degraded DNA and DNA contaminated with humic acid, heme and indigo dye. Both IAC₉₀ and IAC₄₁₀ were successfully amplified with human DNA without significantly affecting the quality of the DNA profile, even with DNA amounts lower than 0.5 ng. In the presence of inhibitors, the IAC₉₀ signal was still present after all human DNA loci fail to amplify; in contrast, the IAC₄₁₀ signal was reduced or absent at low levels of inhibition. Amplification of the two IACs provided an internal PCR control and allowed partial profiles caused by inhibition to be distinguished from degraded DNA profiles.

  16. Utilization of nanoparticle labels for signal amplification in ultrasensitive electrochemical affinity biosensors: a review. (United States)

    Ding, Liang; Bond, Alan M; Zhai, Jianping; Zhang, Jie


    Nanoparticles with desirable properties not exhibited by the bulk material can be readily synthesized because of rapid technological developments in the fields of materials science and nanotechnology. In particular their highly attractive electrochemical properties and electrocatalytic activity have facilitated achievement of the high level of signal amplification needed for the development of ultrasensitive electrochemical affinity biosensors for the detection of proteins and DNA. This review article explains the basic principles of nanoparticle based electrochemical biosensors, highlights the recent advances in the development of nanoparticle based signal amplification strategies, and provides a critical assessment of the likely drawbacks associated with each strategy. Finally, future perspectives for achieving advanced signal simplification in nanoparticles based biosensors are considered.

  17. Active Amplification of the Terrestrial Albedo to Mitigate Climate Change: An Exploratory Study

    CERN Document Server

    Hamwey, R M


    This study explores the potential to enhance the reflectance of solar insolation by the human settlement and grassland components of the Earth's terrestrial surface as a climate change mitigation measure. Preliminary estimates derived using a static radiative transfer model indicate that such efforts could amplify the planetary albedo enough to offset the current global annual average level of radiative forcing caused by anthropogenic greenhouse gases by as much as 30 percent or 0.76 W/m2. Terrestrial albedo amplification may thus extend, by about 25 years, the time available to advance the development and use of low-emission energy conversion technologies which ultimately remain essential to mitigate long-term climate change. However, additional study is needed to confirm the estimates reported here and to assess the economic and environmental impacts of active land-surface albedo amplification as a climate change mitigation measure.

  18. Rapid amplification of genetically modified organisms using a circular ferrofluid-driven PCR microchip. (United States)

    Sun, Yi; Kwok, Yien-Chian; Foo-Peng Lee, Peter; Nguyen, Nam-Trung


    The use of genetically modified organisms (GMOs) as food and in food products is becoming more and more widespread. Polymerase chain reaction (PCR) technology is extensively used for the detection of GMOs in food products in order to verify compliance with labeling requirements. In this paper, we present a novel close-loop ferrofluid-driven PCR microchip for rapid amplification of GMOs. The microchip was fabricated in polymethyl methacrylate by CO2 laser ablation and was integrated with three temperature zones. PCR solution was contained in a circular closed microchannel and was driven by magnetic force generated by an external magnet through a small oil-based ferrofluid plug. Successful amplification of genetically modified soya and maize were achieved in less than 13 min. This PCR microchip combines advantages of cycling flexibility and quick temperature transitions associated with two existing microchip PCR techniques, and it provides a cost saving and less time-consuming way to conduct preliminary screening of GMOs.

  19. Control and amplification of cortical neurodynamics (United States)

    Liljenstroem, Hans; Aronsson, P.


    We investigate different mechanisms for the control and amplification of cortical neurodynamics, using a neural network model of a three layered cortical structure. We show that different dynamical states can be obtained by changing a control parameter of the input-output relation, or by changing the noise level. Point attractor, limit cycle, and strange attractor dynamics occur at different values of the control parameter. For certain, optimal noise levels, system performance is maximized, analogous to stochastic resonance phenomena. Noise can also be used to induce different dynamical states. A few noisy network units distributed in a network layer can result in global synchronous oscillations, or waves of activity moving across the network. We further demonstrate that fast synchronization of network activity can be obtained by implementing electromagnetic interactions between network units.

  20. Amplification sans bruit d'images optiques (United States)

    Gigan, S.; Delaubert, V.; Lopez, L.; Treps, N.; Maitre, A.; Fabre, C.


    Nous utilisons un Oscillateur Paramétrique Optique (OPO) pompé sous le seuil dans le but d'amplifier une image multimode transverse sans dégradation du rapport signal à bruit. Le dispositif expérimental met en œuvre un OPO de type II triplement résonant et semi-confocal pour le faisceau amplifié. L'existence d'effets quantiques lors de l'amplification multimode dans un tel dispositif a été montrée expérimentalement. Plus généralement, ceci nous a amené à étudier les propriétés quantiques transverses des faisceaux lumineux amplifiés. Une telle étude peut trouver des applications non seulement en imagerie, mais également dans le traitement quantique de l'information.

  1. Dispersion compensation in chirped pulse amplification systems (United States)

    Bayramian, Andrew James; Molander, William A.


    A chirped pulse amplification system includes a laser source providing an input laser pulse along an optical path. The input laser pulse is characterized by a first temporal duration. The system also includes a multi-pass pulse stretcher disposed along the optical path. The multi-pass pulse stretcher includes a first set of mirrors operable to receive input light in a first plane and output light in a second plane parallel to the first plane and a first diffraction grating. The pulse stretcher also includes a second set of mirrors operable to receive light diffracted from the first diffraction grating and a second diffraction grating. The pulse stretcher further includes a reflective element operable to reflect light diffracted from the second diffraction grating. The system further includes an amplifier, a pulse compressor, and a passive dispersion compensator disposed along the optical path.

  2. Magnetic field amplification in turbulent astrophysical plasmas

    CERN Document Server

    Federrath, Christoph


    Magnetic fields play an important role in astrophysical accretion discs, and in the interstellar and intergalactic medium. They drive jets, suppress fragmentation in star-forming clouds and can have a significant impact on the accretion rate of stars. However, the exact amplification mechanisms of cosmic magnetic fields remain relatively poorly understood. Here I start by reviewing recent advances in the numerical and theoretical modelling of the 'turbulent dynamo', which may explain the origin of galactic and inter-galactic magnetic fields. While dynamo action was previously investigated in great detail for incompressible plasmas, I here place particular emphasis on highly compressible astrophysical plasmas, which are characterised by strong density fluctuations and shocks, such as the interstellar medium. I find that dynamo action works not only in subsonic plasmas, but also in highly supersonic, compressible plasmas, as well as for low and high magnetic Prandtl numbers. I further present new numerical simu...

  3. Anisotropic metamaterials with simultaneous attenuation and amplification

    CERN Document Server

    Mackay, Tom G


    Anisotropic metamaterials that are neither wholly dissipative nor wholly active at a specific frequency are permitted by classical electromagnetic theory. Well-established formalisms for the homogenization of particulate composite materials indicate that such a metamaterial may be conceptualized quite simply as a random mixture of electrically small spheroidal particles of at least two different isotropic dielectric materials, one of which must be dissipative but the other active. The realization of this metametarial is influenced by the volume fraction, spatial distribution, particle shape and size, and the relative permittivities of the component materials. Metamaterials displaying both dissipation and amplification at the same frequency with more complicated linear as well as nonlinear constitutive properties are possible.

  4. Integrated Amplification Microarrays for Infectious Disease Diagnostics

    Directory of Open Access Journals (Sweden)

    Darrell P. Chandler


    Full Text Available This overview describes microarray-based tests that combine solution-phase amplification chemistry and microarray hybridization within a single microfluidic chamber. The integrated biochemical approach improves microarray workflow for diagnostic applications by reducing the number of steps and minimizing the potential for sample or amplicon cross-contamination. Examples described herein illustrate a basic, integrated approach for DNA and RNA genomes, and a simple consumable architecture for incorporating wash steps while retaining an entirely closed system. It is anticipated that integrated microarray biochemistry will provide an opportunity to significantly reduce the complexity and cost of microarray consumables, equipment, and workflow, which in turn will enable a broader spectrum of users to exploit the intrinsic multiplexing power of microarrays for infectious disease diagnostics.

  5. Magnetic Field Amplification and Blazar Flares

    CERN Document Server

    Chen, Xuhui; Fossati, Giovanni; Pohl, Martin


    Recent multiwavelength observations of PKS 0208-512 by SMARTS, Fermi, and Swift revealed that gamma-ray and optical light curves of this flat spectrum radio quasars are highly correlated, but with an exception of one large optical flare having no corresponding gamma-ray activity or even detection. On the other hand, recent advances in SNRs observations and plasma simulations both reveal that magnetic field downstream of astrophysical shocks can be largely amplified beyond simple shock compression. These amplifications, along with their associated particle acceleration, might contribute to blazar flares, including the peculiar flare of PKS 0208-512. Using our time dependent multizone blazar emission code, we evaluate several scenarios that may represent such phenomena. This code combines Monte Carlo method that tracks the radiative processes including inverse Compton scattering, and Fokker-Planck equation that follows the cooling and acceleration of particles. It is a comprehensive time dependent code that ful...

  6. Optimization of Extract Technology for Chlorogenic Acid in Burdock%牛蒡根中绿原酸提取工艺的优化

    Institute of Scientific and Technical Information of China (English)



    The extraction technology with methanol was studied for chlorogenic acid in burdock. The sin-gle factor test was conducted to study the effects of methanol concentration, temperature, extracting time and Ph value on extracting rate of chlorogenic acid, and the orthogonal test was carried out to optimize the factors. The results showed that the optimal extraction technology was extracting chlorogenic acid from burdock with 40% methanol concentration under 60℃ and 4. 0 of Ph value for 1. 5 hours, and the extracting rate could reach 0.539%.%研究了醇法提取牛蒡根绿原酸的工艺.通过单因素试验探讨甲醇浓度、温度、时间、pH值对绿原酸提取率的影响,并通过正交试验对影响绿原酸提取率的参数进行优化.结果表明:牛蒡根绿原酸提取的最佳工艺条件为:甲醇浓度40%、温度60℃、时间1.5h、pH4.0,此条件下绿原酸提取率为0.539%.

  7. Ethosomes® and transfersomes® containing linoleic acid: physicochemical and technological features of topical drug delivery carriers for the potential treatment of melasma disorders. (United States)

    Celia, Christian; Cilurzo, Felisa; Trapasso, Elena; Cosco, Donato; Fresta, Massimo; Paolino, Donatella


    Two vesicular colloidal carriers, ethosomes® and transfersomes® were proposed for the topical delivery of linoleic acid, an active compound used in the therapeutic treatment of hyperpigmentation disorders, i.e. melasma, which is characterized by an increase of the melanin production in the epidermis. Dynamic light scattering was used for the physicochemical characterization of vesicles and mean size, size distribution and zeta potential were evaluated. The stability of formulations was also evaluated using the Turbiscan Lab® Expert based on the analysis of sample transmittance and photon backscattering. Ethosomes® and transfersomes® were prepared using Phospholipon 100 G®, as the lecithin component, and ethanol and sodium cholate, as edge activator agents, respectively. Linoleic acid at 0.05% and 0.1% (w/v) was used as the active ingredient and entrapped in colloidal vesicles. Technological parameters, i.e. entrapment efficacy, drug release and permeation profiles, were also investigated. Experimental findings showed that physicochemical and technological features of ethosomes® and transfersomes® were influenced by the lipid composition of the carriers. The percutaneous permeation experiments of linoleic acid-loaded ethosomes® and transfersomes® through human stratum corneum-epidermidis membranes showed that both carriers are accumulated in the skin membrane model as a function of their lipid compositions. The findings reported in this investigation showed that both vesicular carriers could represent a potential system for the topical treatment of hyperpigmentation disorders.

  8. Short-Pulse Amplification by Strongly-Coupled Brillouin Scattering

    CERN Document Server

    Edwards, Matthew R; Mikhailova, Julia M; Fisch, Nathaniel J


    We examine the feasibility of strongly-coupled stimulated Brillouin scattering as a mechanism for the plasma-based amplification of sub-picosecond pulses. In particular, we use fluid theory and particle-in-cell simulations to compare the relative advantages of Raman and Brillouin amplification over a broad range of achievable parameters.

  9. A Theoretical Evaluation of Optical Parametric Amplification in BBO Crystal

    Institute of Scientific and Technical Information of China (English)

    邵敏; 薛绍林; 林尊琪


    The noncollinear optical parametric amplification in BBO crystal is theoretically investigated. The phase matching angle, gain bandwidth, optimal noncollinear angle and conversion efficiency for both type-Ⅰ and type-Ⅱ BBO are simulated. The numerical simulation results are important to the practical optical parametric amplification experiments with BBO crystal.

  10. Communications technology (United States)

    Cuccia, C. Louis; Sivo, Joseph


    The technologies for optimized, i.e., state of the art, operation of satellite-based communications systems are surveyed. Features of spaceborne active repeater systems, low-noise signal amplifiers, power amplifiers, and high frequency switches are described. Design features and capabilities of various satellite antenna systems are discussed, including multiple beam, shaped reflector shaped beam, offset reflector multiple beam, and mm-wave and laser antenna systems. Attitude control systems used with the antenna systems are explored, along with multiplexers, filters, and power generation, conditioning and amplification systems. The operational significance and techniques for exploiting channel bandwidth, baseband and modulation technologies are described. Finally, interconnectivity among communications satellites by means of RF and laser links is examined, as are the roles to be played by the Space Station and future large space antenna systems.

  11. Targeting HER2 amplifications in gastric cancer

    Directory of Open Access Journals (Sweden)

    Ung L


    Full Text Available Lawson Ung, Terence C Chua, Neil D Merrett Department of Surgery, South Western Sydney Upper GI Surgical Unit, Bankstown Hospital, University of Western Sydney, Sydney, NSW, Australia Abstract: While multimodality treatments, including neoadjuvant and adjuvant chemotherapy or chemoradiation, have become the global standard of care in patients with locally advanced and metastatic gastric cancers (GCs, long-term outcomes for patients remain poor. This reflects the aggressive tumor biology of GCs and occult nature of the disease, often presenting in its advanced stages, as well as the challenges of developing effective targeted therapy to treat this disease. The Trastuzumab for Gastric Cancer trial demonstrates that the addition of human epidermal growth factor 2 (HER2 monoclonal antibody trastuzumab to standard chemotherapy regimen consisting of 5-fluorouracil (5-FU or capecitabine with cisplatin results in significant improvement in overall and progression-free survival. Although questions remain regarding the best methods by which to determine HER2 mutation positivity and amplification, through immunohistochemistry or in situ hybridization, and whether trastuzumab is effective for locally advanced, nonmetastatic GC in an adjuvant setting, the trial has led to a surge of clinical trials investigating the potential role of other HER2- and non-HER2-targeted therapies to improve patient outcomes. This review will discuss our current understanding of GC pathogenesis, current available treatments, and the potential impact that targeting HER2 amplifications may have in our efforts to individualize and optimize cancer care in GC individuals. Keywords: Personalized cancer therapy, surgical oncology, gastrectomy, adjuvant treatment, targeted therapies

  12. Mutualism breakdown by amplification of Wolbachia genes. (United States)

    Chrostek, Ewa; Teixeira, Luis


    Most insect species are associated with vertically transmitted endosymbionts. Because of the mode of transmission, the fitness of these symbionts is dependent on the fitness of the hosts. Therefore, these endosymbionts need to control their proliferation in order to minimize their cost for the host. The genetic bases and mechanisms of this regulation remain largely undetermined. The maternally inherited bacteria of the genus Wolbachia are the most common endosymbionts of insects, providing some of them with fitness benefits. In Drosophila melanogaster, Wolbachia wMelPop is a unique virulent variant that proliferates massively in the hosts and shortens their lifespan. The genetic bases of wMelPop virulence are unknown, and their identification would allow a better understanding of how Wolbachia levels are regulated. Here we show that amplification of a region containing eight Wolbachia genes, called Octomom, is responsible for wMelPop virulence. Using Drosophila lines selected for carrying Wolbachia with different Octomom copy numbers, we demonstrate that the number of Octomom copies determines Wolbachia titers and the strength of the lethal phenotype. Octomom amplification is unstable, and reversion of copy number to one reverts all the phenotypes. Our results provide a link between genotype and phenotype in Wolbachia and identify a genomic region regulating Wolbachia proliferation. We also prove that these bacteria can evolve rapidly. Rapid evolution by changes in gene copy number may be common in endosymbionts with a high number of mobile elements and other repeated regions. Understanding wMelPop pathogenicity and variability also allows researchers to better control and predict the outcome of releasing mosquitoes transinfected with this variant to block human vector-borne diseases. Our results show that transition from a mutualist to a pathogen may occur because of a single genomic change in the endosymbiont. This implies that there must be constant selection on

  13. Technological challenges to assess n-3 polyunsaturated fatty acids from marine oils for nutritional and pharmacological use

    Directory of Open Access Journals (Sweden)

    Valenzuela, A.


    Full Text Available The benefits ascribed to marine oils rich in n-3 polyunsaturated fatty acids has led to efforts to improve the chemical and organoleptic characteristics of these oils and to develop procedures for the obtention of pure or highly concentrated fractions of some n-3 fatty acids. Two n-3 fatty acids are of main interest; the eicosapentaenoic acid (C20:5, EPA and the docosahexaenoic acid (022:6, DHA. The present review is referred to the identification of the main sources of marine n-3 polyunsaturated fatty acids, and to the stabilization of these fatty acids against oxidative rancidity. In addition the procedures for the obtention of EPA and DHA concentrates and the utilization of these fatty acids for nutritional or pharmacological purposes are also discussed.

    Los beneficios atribuidos a los aceites marinos ricos en ácidos grasos n-3 poliinsaturados han conducido a un esfuerzo por mejorar las características químicas y organolépticas de estos aceites y al desarrollo de procedimientos para la obtención de fracciones altamente concentradas o puras de ácidos grasos n-3. Dos ácidos grasos n-3 de interés principal son el ácido eicosapentaenoico (C20:5, EPA y el ácido docosahexaenoico (022:6, DHA. La presente revisión está referida a la identificación de las principales fuentes de ácidos grasos n-3 poliinsaturados marinos, y a la estabilización de estos ácidos frente a la rancidez oxidativa. Además de los procedimientos para la obtención de concentrados de EPA y DHA, es también discutida la utilización de estos ácidos grasos para usos nutricionales y farmacológicos.

  14. Hendra virus detection using Loop-Mediated Isothermal Amplification. (United States)

    Foord, Adam J; Middleton, Deborah; Heine, Hans G


    Hendra virus (HeV) is a zoonotic paramyxovirus endemic in Australian Pteropus bats (fruit bats or flying foxes). Although bats appear to be unaffected by the virus, HeV can spread from fruit bats to horses, causing severe disease. Human infection results from close contact with the blood, body fluids and tissues of infected horses. HeV is a biosecurity level 4 (BSL-4) pathogen, with a high case-fatality rate in humans and horses. Current assays for HeV detection require complex instrumentation and are generally time consuming. The aim of this study was to develop a Loop-Mediated Isothermal Amplification (LAMP) assay to detect nucleic acid from all known HeV strains in horses without the requirement for complex laboratory equipment. A LAMP assay targeting a conserved region of the HeV P-gene was combined with a Lateral Flow Device (LFD) for detection of amplified product. All HeV isolates, the original HeV isolated in 1994 as well as the most recent isolates from 2011 were detected. Analytical sensitivity and specificity of the HeV-LAMP assay was equal to a TaqMan assay developed previously. Significantly, these assays detected HeV in horses before clinical signs were observed. The combined LAMP-LFD procedure is a sensitive method suitable for HeV diagnosis in a resource-limited situation or where rapid test results are critical.

  15. Production Technology of Liquid Humic Acid Bio-fertilizer%腐植酸液体生物肥料的工艺技术改进

    Institute of Scientific and Technical Information of China (English)



    The market prospects of liquid humic acid bio-fertilizer are introduced in this paper. The core of technical formula, process flow, the rate of raw material consumption, the results of practical application are also introduced. Thus a comprehensive description and summary of liquid humic acid bio-fertilizers' technology is given.%通过对腐植酸液体生物肥料的市场前景、改进后的核心技术配方、工艺流程、原材料消耗定额、实际应用结果等介绍,对腐植酸液体生物肥料的工艺技术进行较为全面的叙述和总结。

  16. Study on Brewing Technology of Vinegar with High Amino Acid%高氨基酸食醋酿造技术的研究

    Institute of Scientific and Technical Information of China (English)

    张春杰; 张茜; 李丽华; 宋春雪


    通过原料创新和工艺创新,融合国内知名食醋酿造工艺,靶向调控食醋中氨基酸含量,研制出鲜香浓郁的高氨基酸醋。该技术增加了中国醋类新品种,提升了食醋品质和营养保健价值。%With innovation of raw materials and process,the brewing process of famous vinegar is fused in the fermentation for target regulating the amino acids in vinegar and a kind of delicious full-bodied vinegar with high amino acid is developed.This technology has increased new varieties of Chi-nese vinegar and enhanced the quality and nutritional value of vinegar.

  17. Use of Peltier effect for small signal amplification and conversion (United States)

    Ageyev, Y. I.; Akperov, M. M.; Kobakhidze, K. Z.; Nebuchinov, M. V.


    It is possible to use thermocouples operating as heat pumps with small temperature gradients to effect the control of elements whose properties are temperature dependent. This enables the construction of a number of electrical and optical signal transducers. The cooling or heating gain of a thermocouple used as a heat pump is proportional to the ratio of the cold or hot junction temperature to the temperature drop across the thermocouple. As this temperature gradient becomes quite small, the efficiency of such converters theoretically rises without limit. Under these conditions, the thermocouple can control any device whose properties change sharply in a narrow temperature range. Simple circuits for small signal amplification, frequency conversion, and detection were discussed. The gain of one such amplifier was plotted as a function of the input signal using various metal-semiconductor phase transition devices; the detection gain was plotted as a function of the input signal for a posistor and a metal-semiconductor phase transition device. Gains on the order of 100 and more were obtained with the latter. While such devices have the advantage of electrically isolating the input from the output, the speed is governed primarily by the rate of the thermal processes and is approximately inversely proportional to the square of thermocouple branch length. The speed is presently limited to tens of milliseconds, though with the transition to film technology, it may increase by a few orders of magnitude.

  18. Progress in multiplex loop-mediated isothermal amplification tech-nology%多重环介导等温扩增技术研究进展

    Institute of Scientific and Technical Information of China (English)

    林文慧; 邹秉杰; 宋沁馨; 周国华


    Loop-mediated isothermal amplification (LAMP) has been widely applied in nucleic acid diagnostics due to its high sensitivity and specificity, high speed and low requirement of equipment. In order to fully leverage these merits, achieve high efficiency and reliability in diagnostics, and expand the applicable fields while keeping low reagent cost, multiplex LAMP technology has been extensively explored in recent years. Common methods for LAMP products detection are mostly based on the double-stranded DNA amplicons or byproducts from the polymerization reaction, so they can only identify the occurrence of amplification reaction but not the origins or specificity of the products. To achieve specific LAMP products detection, researchers developed various multiplex methods by im-proving the conventional LAMP technology or coupling LAMP with other assays. However, the interference and/or the different amplification efficiencies among different primer sets often lead to biased amplification and thus limited multiplexing level. We here defined these methods as narrow-sensed multiplex LAMP. The research on miniaturized amplification technology which is booming in recent years has given rise to the novel general-sensed multiplex LAMP technology that breaks this limitation by its capability to perform highly parallel and miniaturized simplex reactions in independent compartments. Methods of this type have additional benefits such as lower reagent cost, higher level of automation, lower risk of cross-contamination and better suitability for on-site detection of multiple targets. In this review, we summarize the recent research progress in multiplex LAMP technology from the following aspects: the principle and design of narrow-sensed LAMP and its amplification optimization, the general-sensed LAMP, and the various applications of all multiplex LAMP technologies in diagnostics.%环介导等温扩增技术(Loop-mediated isothermal amplification, LAMP)因其扩增速度快、

  19. Lactic acid bacteria from Sheep's Dhan, a traditional butter from sheep's milk: Isolation, identification and major technological traits

    Energy Technology Data Exchange (ETDEWEB)

    Idoui, T.; Boudjerda, J.; Leghouchi, E.; Karam, N. E.


    Twenty six lactic acid bacteria were isolated from sheep's Dhan, a traditional butter made from sheep's milk in Jijel (East of Algeria). These strains belong to three genera: Lactococcus, Leuconostoc and Lactobacillus. The results showed that Lactococcus lactic ssp diacetylactis was the predominant species in this traditional butter. The results of the assessment of the technological aptitude indicate that a major strain has a good acidification aptitude, some of them show good proteolytic activity and only Leuconostoc mesenteroides ssp. dextranicum isolates were able to produce exo polysaccharide. (Author) 42 refs.

  20. 丁二酸生产工艺技术进展%Research progress of production technology on succinic acid

    Institute of Scientific and Technical Information of China (English)

    杨如惠; 杨效军


    The present development of succic acid were introduced,and the main methods of production were reviewed,including the electrochemical process,the catalytic hydrogenation of maleic anhydride process and the biological fermentation process.It was pointed out the research direction of succinic acid.%简述了丁二酸的发展现状,介绍了目前丁二酸的主要生产方法,包括电化学法、顺酐催化加氢法和生物发酵法,并指出丁二酸的发展前景。

  1. Rapid detection of Brucella spp. using loop-mediated isothermal amplification (LAMP). (United States)

    Chen, Shouyi; Li, Xunde; Li, Juntao; Atwill, Edward R


    Brucella spp. are facultative intracellular bacteria that cause zoonotic disease of brucellosis worldwide. Livestock that are most vulnerable to brucellosis include cattle, goats, and pigs. Brucella spp. cause serious health problems to humans and animals and economic losses to the livestock industry. Traditional methods for detection of Brucella spp. take 48-72 h (Kumar et al., J Commun Dis 29:131-137, 1997; Barrouin-Melo et al., Res Vet Sci 83:340-346, 2007) that do not meet the food industry's need of rapid detection. Therefore, there is an urgent need of fast, specific, sensitive, and inexpensive method for diagnosing of Brucella spp. Loop-mediated isothermal amplification (LAMP) is a method to amplify nucleic acid at constant temperatures. Amplification can be detected by visual detection, fluorescent stain, turbidity, and electrophoresis. We targeted at the Brucella-specific gene omp25 and designed LAMP primers for detection of Brucella spp. Amplification of DNA with Bst DNA polymerase can be completed at 65 °C in 60 min. Amplified products can be detected by SYBR Green I stain and 2.0% agarose gel electrophoresis. The LAMP method is feasible for detection of Brucella spp. from blood and milk samples.

  2. Development of a Loop-Mediated Isothermal Amplification Assay for Porcine Circovirus Type 2

    Institute of Scientific and Technical Information of China (English)

    Ye-bing Liu; Lei Zhang; Qin-hong Xue; Yi-bao Ning; Zhi-gang Zhang


    In this study,the loop-mediated isothermal amplification(LAMP)method was used to develop a rapid and simple detection system for porcine circovirus type 2(PCV2).According to the PCV2 sequences published in GenBank,multiple LAMP primers were designed targeting conserved sequences of PCV2.Using the DNA extracted from PCV2 isolates HUN-09 and SD-09 as the template,LAMP reactions in a PCV2 LAMP system was performed,the amplification products were detected by adding SYBR Green I and could be observed directly by the naked eye.The results showed highly-efficient and specific amplification in 30 min at 63℃ with a LAMP real-time turbidimeter.Furthermore,PCV2 DNA templates,with a detection limit of 5.5×10-5ng of nucleic acid,indicated that this assay was highly sensitive.The results obtained with the naked eye after SYBR Green I staining were consistent with those detected by the real-time turbidimeter,showing the potential simplicity of interpretation of the assay results.The LAMP assay appeared to have greater accuracy than PCR and virus isolation for the analysis of 18 clinical samples.In addition it offers higher specificity and sensitivity,shorter reaction times and simpler procedures than the currently available methods of PCV2 detection.It is therefore a promising tool for the effective and efficient detection of PCV2.

  3. GMO detection in food and feed through screening by visual loop-mediated isothermal amplification assays. (United States)

    Wang, Cong; Li, Rong; Quan, Sheng; Shen, Ping; Zhang, Dabing; Shi, Jianxin; Yang, Litao


    Isothermal DNA/RNA amplification techniques are the primary methodology for developing on-spot rapid nucleic acid amplification assays, and the loop-mediated isothermal amplification (LAMP) technique has been developed and applied in the detection of foodborne pathogens, plant/animal viruses, and genetically modified (GM) food/feed contents. In this study, one set of LAMP assays targeting on eight frequently used universal elements, marker genes, and exogenous target genes, such as CaMV35S promoter, FMV35S promoter, NOS, bar, cry1Ac, CP4 epsps, pat, and NptII, were developed for visual screening of GM contents in plant-derived food samples with high efficiency and accuracy. For these eight LAMP assays, their specificity was evaluated by testing commercial GM plant events and their limits of detection were also determined, which are 10 haploid genome equivalents (HGE) for FMV35S promoter, cry1Ac, and pat assays, as well as five HGE for CaMV35S promoter, bar, NOS terminator, CP4 epsps, and NptII assays. The screening applicability of these LAMP assays was further validated successfully using practical canola, soybean, and maize samples. The results suggested that the established visual LAMP assays are applicable and cost-effective for GM screening in plant-derived food samples.

  4. Kinetic Hairpin Oligonucleotide Blockers for Selective Amplification of Rare Mutations (United States)

    Jia, Yanwei; Sanchez, J. Aquiles; Wangh, Lawrence J.


    Detection of rare mutant alleles in an excess of wild type alleles is increasingly important in cancer diagnosis. Several methods for selective amplification of a mutant allele via the polymerase chain reaction (PCR) have been reported, but each of these methods has its own limitations. A common problem is that Taq DNA polymerase errors early during amplification generate false positive mutations which also accumulate exponentially. In this paper, we described a novel method using hairpin oligonucleotide blockers that can selectively inhibit the amplification of wild type DNA during LATE-PCR amplification. LATE-PCR generates double-stranded DNA exponentially followed by linear amplification of single-stranded DNA. The efficiency of the blocker is optimized by adjusting the LATE-PCR temperature cycling profile. We also demonstrate that it is possible to minimize false positive signals caused by Taq DNA polymerase errors by using a mismatched excess primer plus a modified PCR profile to preferentially enrich for mutant target sequences prior to the start of the exponential phase of LATE-PCR amplification. In combination these procedures permit amplification of specific KRAS mutations in the presence of more than 10,000 fold excess of wild type DNA without false positive signals. PMID:25082368

  5. An integrated closed-tube 2-plex PCR amplification and hybridization assay with switchable lanthanide luminescence based spatial detection. (United States)

    Lahdenperä, Susanne; Spangar, Anni; Lempainen, Anna-Maija; Joki, Laura; Soukka, Tero


    Switchable lanthanide luminescence is a binary probe technology that inherently enables a high signal modulation in separation-free detection of DNA targets. A luminescent lanthanide complex is formed only when the two probes hybridize adjacently to their target DNA. We have now further adapted this technology for the first time in the integration of a 2-plex polymerase chain reaction (PCR) amplification and hybridization-based solid-phase detection of the amplification products of the Staphylococcus aureus gyrB gene and an internal amplification control (IAC). The assay was performed in a sealed polypropylene PCR chip containing a flat-bottom reaction chamber with two immobilized capture probe spots. The surface of the reaction chamber was functionalized with NHS-PEG-azide and alkyne-modified capture probes for each amplicon, labeled with a light harvesting antenna ligand, and covalently attached as spots to the azide-modified reaction chamber using a copper(i)-catalyzed azide-alkyne cycloaddition. Asymmetric duplex-PCR was then performed with no template, one template or both templates present and with a europium ion carrier chelate labeled probe for each amplicon in the reaction. After amplification europium fluorescence was measured by scanning the reaction chamber as a 10 × 10 raster with 0.6 mm resolution in time-resolved mode. With this assay we were able to co-amplify and detect the amplification products of the gyrB target from 100, 1000 and 10,000 copies of isolated S. aureus DNA together with the amplification products from the initial 5000 copies of the synthetic IAC template in the same sealed reaction chamber. The addition of 10,000 copies of isolated non-target Escherichia coli DNA in the same reaction with 5000 copies of the synthetic IAC template did not interfere with the amplification or detection of the IAC. The dynamic range of the assay for the synthetic S. aureus gyrB target was three orders of magnitude and the limit of detection of 8 p

  6. Optimization of Acetic Acid Fermentation Technology of Gujube Vinegar%枣醋醋酸发酵工艺优化

    Institute of Scientific and Technical Information of China (English)

    郑战伟; 张宝善; 王静; 陈菁; 祁春燕


    On the basis of previous studies, the author studied jujube vinegar fermented by static fermentation, and the four single factors on the impact of acetic acid fermentation. The results showed that acetic acid fermentation temperature reached 32T, kiwi mash with the acidity levels of 2.4g/100mL added 6.67%, the ratio of membrane area and volume of wort was 0.2cm2/ml, and the alcohol into acetic acid fermentation was adjusted to 9%. While the orthogonal test to optimize the design, the optimal combination was obtained.%文章在前人研究用表面静止法发酵酿制枣醋的基础上,进一步研究探讨了四个单因素对其醋酸发酵产酸含量的影响,得出结论:醋酸发酵温度为35℃,添加含量为6.67%,酸度为2.4g/100mL的猕猴桃醪液,膜面积与醪液体积比为0.2cm2/mL,调整进入醋酸发酵时酒精度至9%,同时通过正交试验对其进行优化设计,得出最优组合.

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

    Directory of Open Access Journals (Sweden)

    Kuntal Mukherjee

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

  8. Detection of HIV cDNA point mutations with rolling-circle amplification arrays. (United States)

    Wu, Lingwei; Liu, Quanjun; Wu, Zhongwei; Lu, Zuhong


    In this paper we describe an isothermal rolling-circle amplification (RCA) protocol to detect gene point mutations on chips. The method is based on an allele-specific oligonucleotide circularization mediated by a special DNA ligase. The probe is circularized when perfect complementary sequences between the probe oligonucleotide and HIV cDNA gene. Mismatches around the ligation site can prevent probe circularization. The circularized probe (C-probe) can be amplified by rolling circle amplification to generate multimeric singlestranded DNA (ssDNA) under isothermal conditions. There are four sequence regions to bind respectively with fluorescent probe, RCA primer, solid probe and HIV cDNA template in the C-probe which we designed. These ssDNA products are hybridized with fluorescent probes and solid probes which are immobilized on a glass slide composing a regular microarray pattern. The fluorescence signals can be monitored by a scanner in the presence of HIV cDNA templates, whereas the probes cannot be circularized and signal of fluorescence cannot be found. The RCA array has capability of high-throughput detection of the point mutation and the single-nucleotide polymorphism (SNP).The development of C-probe-based technologies offers a promising prospect for situ detection, microarray, molecular diagnosis, single nucleotide polymorphism, and whole genome amplification.

  9. A Novel Low Temperature PCR Assured High-Fidelity DNA Amplification

    Directory of Open Access Journals (Sweden)

    Shaoxia Zhou


    Full Text Available As previously reported, a novel low temperature (LoTemp polymerase chain reaction (PCR catalyzed by a moderately heat-resistant (MHR DNA polymerase with a chemical-assisted denaturation temperature set at 85 °C instead of the conventional 94–96 °C can achieve high-fidelity DNA amplification of a target DNA, even after up to 120 PCR thermal cycles. Furthermore, such accurate amplification is not achievable with conventional PCR. Now, using a well-recognized L1 gene segment of the human papillomavirus (HPV type 52 (HPV-52 as the template for experiments, we demonstrate that the LoTemp high-fidelity DNA amplification is attributed to an unusually high processivity and stability of the MHR DNA polymerase whose high fidelity in template-directed DNA synthesis is independent of non-existent 3'–5' exonuclease activity. Further studies and understanding of the characteristics of the LoTemp PCR technology may facilitate implementation of DNA sequencing-based diagnostics at the point of care in community hospital laboratories.

  10. Real-time quantitative nicking endonuclease-mediated isothermal amplification with small molecular beacons. (United States)

    Xu, Wentao; Wang, Chenguang; Zhu, Pengyu; Guo, Tianxiao; Xu, Yuancong; Huang, Kunlun; Luo, Yunbo


    Techniques of isothermal amplification have recently made great strides, and have generated significant interest in the field of point-of-care detection. Nicking endonuclease-mediated isothermal amplification (NEMA) is an example of simple isothermal technology. In this paper, a real-time quantitative nicking endonuclease-mediated isothermal amplification with small molecular beacons (SMB-NEMA) of improved specificity and sensitivity is described. First, we optimized the prohibition of de novo synthesis by choosing Nt·BstNBI endonuclease. Second, the whole genome was successfully amplified with Nt·BstNBI (6 U), betaine (1 M) and trehalose (60 mM) for the first time. Third, we achieved 10 pg sensitivity for the first time after adding a small molecular beacon that spontaneously undergoes a conformational change when hybridizing to target, and the practical test validated the assay's application. The small molecular beacon has a similar melting temperature to the reaction temperature, but is approximately 10 bp shorter than the length of a traditional molecular beacon. A new threshold regulation was also established for isothermal conditions. Finally, we established a thermodynamic model for designing small molecular beacons. This multistate model is more correct than the traditional algorithm. This theoretical and practical basis will help us to monitor SMB-NEMA in a quantitative way. In summary, our SMB-NEMA method allows the simple, specific and sensitive assessment of isothermal DNA quantification.

  11. Detection of HIV cDNA Point Mutations with Rolling-Circle Amplification Arrays

    Directory of Open Access Journals (Sweden)

    Zhongwei Wu


    Full Text Available In this paper we describe an isothermal rolling-circle amplification (RCA protocol to detect gene point mutations on chips. The method is based on an allele-specific oligonucleotide circularization mediated by a special DNA ligase. The probe is circularized when perfect complementary sequences between the probe oligonucleotide and HIV cDNA gene. Mismatches around the ligation site can prevent probe circularization. The circularized probe (C-probe can be amplified by rolling circle amplification to generate multimeric singlestranded DNA (ssDNA under isothermal conditions. There are four sequence regions to bind respectively with fluorescent probe, RCA primer, solid probe and HIV cDNA template in the C-probe which we designed. These ssDNA products are hybridized with fluorescent probes and solid probes which are immobilized on a glass slide composing a regular microarray pattern. The fluorescence signals can be monitored by a scanner in the presence of HIV cDNA templates, whereas the probes cannot be circularized and signal of fluorescence cannot be found. The RCA array has capability of high-throughput detection of the point mutation and the single-nucleotide polymorphism (SNP.The development of C-probe-based technologies offers a promising prospect for situ detection, microarray, molecular diagnosis, single nucleotide polymorphism, and whole genome amplification.

  12. A novel modification of real-time AS-qPCR by using locked nucleic acid-modified oligonucleotide probe as wild type allele amplification blockers for quantitative detection of the JAK2 V617F mutation%评价AS-LNA-qPCR法检测JAK2 V617F突变率的临床应用价值

    Institute of Scientific and Technical Information of China (English)

    邵冬华; 梁国威; 何美琳; 曹清芸


    Objective To develop a novel real-time PCR for sensitively quantitative detection of JAK2 V617F allele burden in peripheral blood.Methods Based on the real-time allele-specific PCR (AS-qPCR),the locked nucleic acid (LNA)-modified oligonucleotide probe was used for selectively blocking amplification of wild-type alleles in AS-qPCR,and then a novel AS-LNA-qPCR method was established.The percentages of sample JAK2 V617F alleles were directly calculated by its threshold cycle (Ct) values according to the standard curve which generated by JAK2 V617F alleles with its Ct values.We validated intra-and inter-assay variability for quantifying JAK2 V617F.We also assayed 623 apparent healthy donors by our method to validate its clinical application value.Results The quantitative lower limit of this method for JAK2 V617F was 0.01%,and the intra-and inter-assay average variability for quantifying percentage of JAK2 V617F in total DNA was 6.3% and 8.6%,respectively.Nineteen JAK2 V617F-positive individuals were identified using AS-LNA-qPCR in blood of 623 apparently healthy donors,and the range of percentages of JAK2 V617F alleles were 0.01%-5.49%.Conclusion The AS-LNA-qPCR with highly sensitive and reproducible quantification of JAK2 V617F mutant burden can be used clinically for diagnosis as well as evaluation of disease prognosis and efficacy of therapy in patients with myeloproliferative neoplasms.%目的 建立一种定量检测外周血细胞酪氨酸激酶2(JAK2)基因V617F突变率的等位基因特异性实时荧光定量PCR(AS-qPCR)方法.方法 在AS-qPCR基础上,引入1条锁核酸(LNA)修饰的寡核苷酸探针,用以选择性抑制AS-qPCR中突变引物对野生等位基因的非特异性扩增,定量检测JAK2 V617F突变率,称之为AS-LNA-qPCR法.通过AS-LNA-qPCR法测定样本的循环阈值(Ct值),根据AS-LNA-qPCR法检测不同JAK2 V617F突变率标准品的Ct值,绘制标准曲线,根据标准曲线直接获得检测样本中JAK2 V617F突变率.

  13. 一步核酸扩增仪术中诊断乳腺癌前哨淋巴结转移的前瞻性、多中心临床观察%Prospective multi-center study of one-step nucleic acid amplification assay for the detection of sentinel lymph nodes metastases in breast cancer patients

    Institute of Scientific and Technical Information of China (English)

    王永胜; 欧阳涛; 吴炅; 刘艳辉; 曹旭晨; 孙晓; 付丽; 廖宁; 杨文涛


    Objective To evaluate the roles of Sysmex RD100i one-step nucleic acid amplification (OSNA) assay in the intraoperative assessments of breast cancer sentinel lymph nodes (SLNs).Methods A total of 552 consecutive prospective patients were enrolled from five centers nationwide from February to December 2010.And SLNs were sliced into alternating 2 mm blocks.The odd blocks were tested by the OSNA assay intraoperatively and the even ones assessed by postoperative histology.In addition,intraoperative histological assessments were performed on the even blocks of 211 patients by frozen section and all blocks by touch imprint cytology.Results A total of 1188 SLNs were removed.The mean turnaround time of the assay was 37.3 min.Thcrc was no significant difference of turnaround time at each center (P =0.074).As compared to postoperative histology,the overall performance of the assay had an accuracy of 91.4% (1086/1188),a sensitivity of 83.7% (159/190) and a specificity of 92.9% (927/998).The sensitivity of the assay was higher than frozen section (77.6% (59/76) vs 69.7% (53/76),P =0.286) and was significantly higher than touch imprint cytology (83.6% (158/189) vs 76.2% (144/189),P =0.044).For nodes with micro-metastases,the sensitivity of the assay was higher than frozen section (8/17 vs 4/17,P =0.289) and was significantly higher than touch imprint cytology (62.5% (30/48) vs 35.4% (17/48),P = 0.007).Conclusion As an accurate and rapid intraoperative assay for assessing breast SLNs,the OSNA assay may replace frozen section and touch imprint cytology for clinical applications.%目的 评估应用一步核酸扩增(OSNA)技术进行乳腺癌前哨淋巴结(SLN)术中检测诊断的价值.方法 共入组2010年2至12月全国5个乳腺病中心的552例原发性乳腺癌患者,术中将SLN根据其质量及短轴长度进行切分后,行OSNA检测和印片细胞学检测,术后行逐层切片病理检测.另外,211例患者术中同时行快速冰

  14. Limits for superfocusing with finite evanescent wave amplification

    CERN Document Server

    Gordon, Reuven


    Perfect lensing using negative refractive index materials and radiationless electromagnetic interference both provide extreme subwavelength focusing by "amplifying" evanescent wave components that are usually lost. This paper provides a relation between the achievable focus spot size, the amplification available and the focal length. This may be considered as a revised version of Abbe's diffraction limit for focusing systems that have evanescent wave amplification. It is useful in comparing the amplification achieved in various subwavelength focusing implementations, as well as determining when it is better to use existing near-field techniques, such as simple diffraction from an aperture or slit, than to attempt complicated superfocusing.

  15. Complementary weak-value amplification with concatenated postselections

    CERN Document Server

    Viza, Gerardo I; Liu, Wei-Tao; Howell, John C


    We measure a transverse momentum kick in a Sagnac interferometer using weak-value amplification with two postselections. The first postselection is controlled by a polarization dependent phase mismatch between both paths of a Sagnac interferometer and the second postselection is controlled by a polarizer at the exit port. By monitoring the darkport of the interferometer, we study the complementary amplification of the concatenated postselections, where the polarization extinction ratio is greater than the contrast of the spatial interference. In this case, we find an improvement in the amplification of the signal of interest by introducing a second postselection to the system.

  16. Fluorescence amplification by electrochemically deposited silver nanowires with fractal architecture. (United States)

    Goldys, Ewa M; Drozdowicz-Tomsia, Krystyna; Xie, Fang; Shtoyko, Tanya; Matveeva, Eva; Gryczynski, Ignacy; Gryczynski, Zygmunt


    Electrochemically deposited silver structures with nanowires 50-100 nm in diameter show high fluorescence amplification and strongly reduced fluorescence lifetimes. Both quantities depend on the structure thickness. With increasing thickness the fluorescence amplification proportionally increases and the fluorescence lifetime decreases. This thickness dependence is caused by fluorophore interaction with a system of plasmon excitations in coupled nanowires extending over micrometer size regions. Thus the amplification is attributed to a combination of extended structure area and strong plasmonic coupling between nanowires which also help to radiatively scatter the fluorescence emission.

  17. Backward Raman amplification in the long-wavelength infrared (United States)

    Johnson, L. A.; Gordon, D. F.; Palastro, J. P.; Hafizi, B.


    The wealth of work in backward Raman amplification in plasma has focused on the extreme intensity limit; however, backward Raman amplification may also provide an effective and practical mechanism for generating intense, broad bandwidth, long-wavelength infrared radiation (LWIR). An electromagnetic simulation coupled with a relativistic cold fluid plasma model is used to demonstrate the generation of picosecond pulses at a wavelength of 10 μm with terawatt powers through backward Raman amplification. The effects of collisional damping, Landau damping, pump depletion, and wave breaking are examined, as well as the resulting design considerations for an LWIR Raman amplifier.

  18. Low cost extraction and isothermal amplification of DNA for infectious diarrhea diagnosis. (United States)

    Huang, Shichu; Do, Jaephil; Mahalanabis, Madhumita; Fan, Andy; Zhao, Lei; Jepeal, Lisa; Singh, Satish K; Klapperich, Catherine M


    In order to counter the common perception that molecular diagnostics are too complicated to work in low resource settings, we have performed a difficult sample preparation and DNA amplification protocol using instrumentation designed to be operated without wall or battery power. In this work we have combined a nearly electricity-free nucleic acid extraction process with an electricity-free isothermal amplification assay to detect the presence of Clostridium difficile (C. difficile) DNA in the stool of infected patients. We used helicase-dependent isothermal amplification (HDA) to amplify the DNA in a low-cost, thermoplastic reaction chip heated with a pair of commercially available toe warmers, while using a simple Styrofoam insulator. DNA was extracted from known positive and negative stool samples. The DNA extraction protocol utilized an air pressure driven solid phase extraction device run using a standard bicycle pump. The simple heater setup required no electricity or battery and was capable of maintaining the temperature at 65°C±2°C for 55 min, suitable for repeatable HDA amplification. Experiments were performed to explore the adaptability of the system for use in a range of ambient conditions. When compared to a traditional centrifuge extraction protocol and a laboratory thermocycler, this disposable, no power platform achieved approximately the same lower limit of detection (1.25×10(-2) pg of C. difficile DNA) while requiring much less raw material and a fraction of the lab infrastructure and cost. This proof of concept study could greatly impact the accessibility of molecular assays for applications in global health.

  19. In vitro amplification of ovine prions from scrapie-infected sheep from Great Britain reveals distinct patterns of propagation

    Directory of Open Access Journals (Sweden)

    Thorne Leigh


    Full Text Available Abstract Background Protein misfolding cyclic amplification (PMCA is a method that facilitates the detection of prions from many sources of transmissible spongiform encephalopathy (TSE. Sheep scrapie represents a unique diversity of prion disease agents in a range of susceptible PRNP genotypes. In this study PMCA was assessed on a range of Great Britain (GB sheep scrapie isolates to determine the applicability to veterinary diagnosis of ovine TSE. Results PrPSc amplification by protein misfolding cyclic amplification (PMCA was assessed as a diagnostic tool for field cases of scrapie. The technique was initially applied to thirty-seven isolates of scrapie from diverse geographical locations around GB, and involved sheep of various breeds and PRNP genotypes. All samples were amplified in either VRQ and/or ARQ PrPC substrate. For PrPSc from sheep with at least one VRQ allele, all samples amplified efficiently in VRQ PrPC but only PrPSc from ARH/VRQ sheep amplified in both substrates. PrPSc from ARQ/ARQ sheep displayed two amplification patterns, one that amplified in both substrates and one that only amplified in ARQ PrPC. These amplification patterns were consistent for a further 14/15 flock/farm mates of these sheep. Furthermore experimental scrapie strains SSBP1, Dawson, CH1641 and MRI were analysed. SSBP1 and Dawson (from VRQ/VRQ sheep amplified in VRQ but not ARQ substrate. MRI scrapie (from ARQ/ARQ sheep nor CH1641 did not amplify in ARQ or VRQ substrate; these strains required an enhanced PMCA method incorporating polyadenylic acid (poly(A to achieve amplification. Conclusions PrPsc from 52 classical scrapie GB field isolates amplified in VRQ or ARQ or both substrates and supports the use of PMCA as a rapid assay for the detection of a wide range of ovine classical scrapie infections involving multiple PRNP genotypes and scrapie strains.

  20. 论电子级氢氟酸的纯化技术及其发展%On Electronic-Grade Hydrofluoric Acid Purification Technology and its Development

    Institute of Scientific and Technical Information of China (English)

    陈林; 邵勇; 朱龙


    After due phosphate rock as the main raw material for the production of fluorine by the national limit for fluoride products have a certain influence.With the rapid development of the international economy,the semiconductor industry has developed rapidly. Electronic grade hydrofluoric acid is the main chemical raw materials and a half monomers.From the current situation of electronic-grade hydrofluoric acid purification technology and the future development of two aspects of the research is intended to explore the development of purification technology,and produce the fluorite strategic conservation to create greater benefits for the economy and society.%磷矿石作为氟生产的主要原料,受到国家限制后,对于氟产品有了一定的影响。随着国际经济的快速发展,半导体产业也迅速发展。电子级氢氟酸是半单体的主要化学原料。从电子级氢氟酸纯化技术的现状和未来发展两个方面展开了研究,意在探索纯化技术的发展,以及对于萤石产生战略性保护,为经济和社会创造更大的效益。

  1. KASER: Knowledge Amplification by Structured Expert Randomization. (United States)

    Rubin, Stuart H; Murthy, S N Jayaram; Smith, Michael H; Trajković, Ljiljana


    In this paper and attached video, we present a third-generation expert system named Knowledge Amplification by Structured Expert Randomization (KASER) for which a patent has been filed by the U.S. Navy's SPAWAR Systems Center, San Diego, CA (SSC SD). KASER is a creative expert system. It is capable of deductive, inductive, and mixed derivations. Its qualitative creativity is realized by using a tree-search mechanism. The system achieves creative reasoning by using a declarative representation of knowledge consisting of object trees and inheritance. KASER computes with words and phrases. It possesses a capability for metaphor-based explanations. This capability is useful in explaining its creative suggestions and serves to augment the capabilities provided by the explanation subsystems of conventional expert systems. KASER also exhibits an accelerated capability to learn. However, this capability depends on the particulars of the selected application domain. For example, application domains such as the game of chess exhibit a high degree of geometric symmetry. Conversely, application domains such as the game of craps played with two dice exhibit no predictable pattern, unless the dice are loaded. More generally, we say that domains whose informative content can be compressed to a significant degree without loss (or with relatively little loss) are symmetric. Incompressible domains are said to be asymmetric or random. The measure of symmetry plus the measure of randomness must always sum to unity.

  2. Local Runup Amplification By Resonant Wave Interactions

    CERN Document Server

    Stefanakis, Themistoklis; Dutykh, Denys


    Until now the analysis of long wave runup on a plane beach has been focused on finding its maximum value, failing to capture the existence of resonant regimes. One-dimensional numerical simulations in the framework of the Nonlinear Shallow Water Equations (NSWE) are used to investigate the Boundary Value Problem (BVP) for plane and non-trivial beaches. Monochromatic waves, as well as virtual wave-gage recordings from real tsunami simulations, are used as forcing conditions to the BVP. Resonant phenomena between the incident wavelength and the beach slope are found to occur, which result in enhanced runup of non-leading waves. The evolution of energy reveals the existence of a quasi-periodic state for the case of sinusoidal waves, the energy level of which, as well as the time required to reach that state, depend on the incident wavelength for a given beach slope. Dispersion is found to slightly reduce the value of maximum runup, but not to change the overall picture. Runup amplification occurs for both leadin...

  3. Protein misfolding cyclic amplification of infectious prions. (United States)

    Morales, Rodrigo; Duran-Aniotz, Claudia; Diaz-Espinoza, Rodrigo; Camacho, Manuel V; Soto, Claudio


    Prions are proteinaceous infectious agents responsible for the transmission of prion diseases. The lack of a procedure for cultivating prions in the laboratory has been a major limitation to the study of the unorthodox nature of this infectious agent and the molecular mechanism by which the normal prion protein (PrP(C)) is converted into the abnormal isoform (PrP(Sc)). Protein misfolding cyclic amplification (PMCA), described in detail in this protocol, is a simple, fast and efficient methodology to mimic prion replication in the test tube. PMCA involves incubating materials containing minute amounts of infectious prions with an excess of PrP(C) and boosting the conversion by cycles of sonication to fragment the converting units, thereby leading to accelerated prion replication. PMCA is able to detect the equivalent of a single molecule of infectious PrP(Sc) and propagate prions that maintain high infectivity, strain properties and species specificity. A single PMCA assay takes little more than 3 d to replicate a large amount of prions, which could take years in an in vivo situation. Since its invention 10 years ago, PMCA has helped to answer fundamental questions about this intriguing infectious agent and has been broadly applied in research areas that include the food industry, blood bank safety and human and veterinary disease diagnosis.

  4. A PCR amplification method without DNA extraction. (United States)

    Li, Hongwei; Xu, Haiyue; Zhao, Chunjiang; Sulaiman, Yiming; Wu, Changxin


    To develop a simple and inexpensive method for direct PCR amplification of animal DNA from tissues, we optimized different components and their concentration in lysis buffer systems. Finally, we acquired the optimized buffer system composed of 10 mmol tris(hydroxymethyl)aminomethane (Tris)-Cl (pH 8.0), 2 mmol ethylene diamine tetraacetic (EDTA) (pH 8.0), 0.2 mol NaCl and 200 μg/mL Proteinase K. Interestingly, the optimized buffer is also very effective when working with common human sample types, including blood, buccal cells and hair. The direct PCR method requires fewer reagents (Tris-Cl, EDTA, Protease K and NaCl) and less incubation time (only 35 min). The cost of treating every sample is less than $0.02, and all steps can be completed on a thermal cycler in a 96-well format. So, the proposed method will significantly improve high-throughput PCR-based molecular assays in animal systems and in common human sample types.

  5. Small Sample Whole-Genome Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Hara, C A; Nguyen, C P; Wheeler, E K; Sorensen, K J; Arroyo, E S; Vrankovich, G P; Christian, A T


    Many challenges arise when trying to amplify and analyze human samples collected in the field due to limitations in sample quantity, and contamination of the starting material. Tests such as DNA fingerprinting and mitochondrial typing require a certain sample size and are carried out in large volume reactions; in cases where insufficient sample is present whole genome amplification (WGA) can be used. WGA allows very small quantities of DNA to be amplified in a way that enables subsequent DNA-based tests to be performed. A limiting step to WGA is sample preparation. To minimize the necessary sample size, we have developed two modifications of WGA: the first allows for an increase in amplified product from small, nanoscale, purified samples with the use of carrier DNA while the second is a single-step method for cleaning and amplifying samples all in one column. Conventional DNA cleanup involves binding the DNA to silica, washing away impurities, and then releasing the DNA for subsequent testing. We have eliminated losses associated with incomplete sample release, thereby decreasing the required amount of starting template for DNA testing. Both techniques address the limitations of sample size by providing ample copies of genomic samples. Carrier DNA, included in our WGA reactions, can be used when amplifying samples with the standard purification method, or can be used in conjunction with our single-step DNA purification technique to potentially further decrease the amount of starting sample necessary for future forensic DNA-based assays.

  6. [Technological process of cell disruption for extracting astaxanthin from Phaffia rhodozyma by acid method under autoclave conditions]. (United States)

    Lu, Baoju; Xiao, Anfeng; Lil, Lijun; Ni, Hui; Cai, Huinong; Su, Wenjin


    Phaffia rhodozyma is one of the organisms for production of astaxanthin, and the key process for extracting intracellular astaxanthin is cell disruption. In this work, cell disruption for extracting astaxanthin from Phaffia rhodozyma was studied with autoclave method at low acid concentration. The optimum disrupting conditions were: autoclave pressure 0.1 MPa, 121 degrees C; hydrochloric acid concentration 0.5 mol/L; liquid to material ratio (V/W) 30 mL/g dry cell weight and disruption time 2 min. Under the optimum conditions, medium scale experiment showed that astaxanthin and total carotenoids recovery from Phaffia rhodozyma were (84.8 +/- 3.2)% and (93.3 +/- 2)%, respectively. This new method can lead to no poisonous residues and get high extraction yield, which have good prospects to be put into industrial production.

  7. Mechanisms of Vanadium Recovery from Stone Coal by Novel BaCO3/CaO Composite Additive Roasting and Acid Leaching Technology

    Directory of Open Access Journals (Sweden)

    Zhenlei Cai


    Full Text Available In this report, the vanadium recovery mechanisms by novel BaCO3/CaO composite additive roasting and acid leaching technology, including the phase transformations and the vanadium leaching kinetics, were studied. The purpose of this manuscript is to realize and improve the vanadium recovery from stone coal using BaCO3/CaO as the composite additive. The results indicated that during the composite additive BaCO3/CaO roasting process, the monoclinic crystalline structure of muscovite (K(Al,V2[Si3AlO10](OH2 was converted into the hexagonal crystalline structure of BaSi4O9 and the tetragonal crystalline structure of Gehlenite (Ca2Al2SiO7, which could, therefore, facilitate the release and extraction of vanadium. Vanadium in leaching residue was probably in the form of vanadate or pyrovanadate of barium and calcium, which were hardly extracted during the sulfuric acid leaching process. The vanadium leaching kinetic analysis indicated that the leaching process was controlled by the diffusion through a product layer. The apparent activation energy could be achieved as 46.51 kJ/mol. The reaction order with respect to the sulfuric acid concentration was 1.1059. The kinetic model of vanadium recovery from stone coal using novel composite additive BaCO3/CaO could be finally established.

  8. Quantum dot layer-by-layer assemblies as signal amplification labels for ultrasensitive electronic detection of uropathogens. (United States)

    Xiang, Yun; Zhang, Haixia; Jiang, Bingying; Chai, Yaqin; Yuan, Ruo


    The preparation and use of a new class of signal amplification label, quantum dot (QD) layer-by-layer (LBL) assembled polystyrene microsphere composite, for amplified ultrasensitive electronic detection of uropathogen-specific DNA sequences is described. The target DNA is sandwiched between the capture probes immobilized on the magnetic beads and the signaling probes conjugated to the QD LBL assembled polystyrene beads. Because of the dramatic signal amplification by the numerous QDs involved in each single DNA binding event, subfemtomolar level detection of uropathogen-specific DNA sequences is achieved, which makes our strategy among the most sensitive electronic approach for nucleic acid-based monitoring of pathogens. Our signal amplified detection scheme could be readily expanded to monitor other important biomolecules (e.g., proteins, peptides, amino acids, cells, etc.) in ultralow levels and thus holds great potential for early diagnosis of disease biomarkers.

  9. Technological, physicochemical and sensory characteristics of a Brazilian semi-hard goat cheese (coalho with added probiotic lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Maria Elieidy Gomes de Oliveira


    Full Text Available Over the past few years, the use of probiotics, which are capable of exerting beneficial effects on the composition of intestinal microbiota, has increased. Cheeses have been suggested as a better carrier of probiotic bacteria than other fermented milk products. The effect of added cultures of probiotic lactic acid bacteria on the quality of a Brazilian goat semi-hard cheese (coalho was assessed during 21 days of storage at 10 ºC as follows: C1, Lactococcus lactis subsp. lactis and L. lactis subsp. Cremoris (standard cheese; C2, Lactobacillus acidophilus (LA-5; C3, Lactobacillus paracasei (Lactobacillus casei-01; C4, BBifidobacterium lactis (BB12; and C5, L. acidophilus, L. paracasei and B. lactis. Differences in some physico-chemical, experimental texture and proteolysis parameters were found among the assessed cheeses. All of them presented high luminosity (L* with predominance of the yellow component (b*. Numbers of lactic acid bacteria in the cheeses were greater than 10(7 cfu g-1 during storage. Cheeses with the added probiotic strains alone and in co-culture were better accepted than cheeses without the probiotic strains. It is suggested that goat "coalho" cheese could be a potential carrier of probiotic lactic acid bacteria.

  10. The determination of calcium, glucose, urea and uric acid using the Kodak EKTACHEM multilayer film technology: an evaluation. (United States)

    Knoll, E; Hafner, F; Dettmer, K; Wisser, H


    Calcium, glucose, urea and uric acid determinations on the "'Kodak Ektachem Four Chemistry Analyzer" were tested for precision and an estimation of the accuracy was performed with our laboratory routine methods using patients' sera and proficiency fluids. Precision -- examined over a period of six weeks -- was very good. Even the very stringent claim of the College of American Pathologists (CAP) -- that analytical dispersion should be less than 1/16th of the normal range -- was fulfilled in almost all control samples. The results from patients' sera measured using both the Ektachem and the routine laboratory methods showed very good correlation. Proficiency fluids tested for calcium, glucose and uric acid all resulted in values well within the assigned interval. Some negative bias was noted for the urea determination however. This could not be completely eliminated even though the samples had been reconstituted with a bicarbonate solution according to the manufacturer's instructions. The linear range of the four determinations was checked: calcium is linear up to 4.2 mmol/l, glucose up to 33 mmol/l, urea up to 60 mmol/l and uric acid up to 1370 mumol/l. Our results confirmed the long-term stability of analyzer and slides to be so high that one calibration per week is sufficient.

  11. Study of reconstruction methods for a time projection chamber with GEM gas amplification system

    Energy Technology Data Exchange (ETDEWEB)

    Diener, R.


    A new e{sup +}e{sup -} linear collider with an energy range up to 1TeV is planned in an international collaboration: the International Linear Collider (ILC). This collider will be able to do precision measurements of the Higgs particle and of physics beyond the Standard Model. In the Large Detector Concept (LDC) - which is one proposal for a detector at the ILC - a Time Projection Chamber (TPC) is foreseen as the main tracking device. To meet the requirements on the resolution and to be able to work in the environment at the ILC, the application of new gas amplification technologies in the TPC is necessary. One option is an amplification system based on Gas Electron Multipliers (GEMs). Due to the - in comparison with older technologies - small spatial width of the signals, this technology poses new requirements on the readout structures and the reconstruction methods. In this work, the performance and the systematics of different reconstruction methods have been studied, based on data measured with a TPC prototype in high magnetic fields of up to 4T and data from a Monte Carlo simulation. The latest results of the achievable point resolution are presented and their limitations have been investigated. (orig.)

  12. Amplification options for patients with mixed hearing loss.

    NARCIS (Netherlands)

    Zwartenkot, J.W.; Snik, A.F.M.; Mylanus, E.A.M.; Mulder, J.J.S.


    OBJECTIVES: To compare amplification options for patients with mixed hearing loss. Devices tested include percutaneous and transcutaneous bone conductors (BCDs) and middle ear implants with their actuator directly coupled to the cochlea. SETTING: Tertiary academic medical center. METHOD AND PARTICIP

  13. Nonlinear Zel'dovich effect: Parametric amplification from medium rotation

    CERN Document Server

    Faccio, Daniele


    The interaction of light with rotating media has attracted recent interest for both fundamental and applied studies including rotational Doppler shift measurements. It is also possible to obtain amplification through the scattering of light with orbital angular momentum from a rotating and absorbing cylinder, as proposed by Zel'dovich more than 40 years ago. This amplification mechanism has never been observed experimentally yet has connections to other fields such as Penrose superradiance in rotating black holes. Here we propose a nonlinear optics system whereby incident light carrying orbital angular momentum drives parametric interaction in a rotating medium. The crystal rotation is shown to take the phase-mismatched parametric interaction with negligible energy exchange at zero rotation to amplification for sufficiently large rotation rates. The amplification is shown to result from breaking of anti-PT symmetry induced by the medium rotation.

  14. Nonlinear Zel'dovich Effect: Parametric Amplification from Medium Rotation (United States)

    Faccio, Daniele; Wright, Ewan M.


    The interaction of light with rotating media has attracted recent interest for both fundamental and applied studies including rotational Doppler shift measurements. It is also possible to obtain amplification through the scattering of light with orbital angular momentum from a rotating and absorbing cylinder, as proposed by Zel'dovich more than forty years ago. This amplification mechanism has never been observed experimentally yet has connections to other fields such as Penrose superradiance in rotating black holes. Here we propose a nonlinear optics system whereby incident light carrying orbital angular momentum drives parametric interaction in a rotating medium. The crystal rotation is shown to take the phase-mismatched parametric interaction with negligible energy exchange at zero rotation to amplification for sufficiently large rotation rates. The amplification is shown to result from breaking of anti-P T symmetry induced by the medium rotation.

  15. The Amplification in FEL with Inhomogeneous Magnetic Field

    CERN Document Server

    Oganesyan, K B


    The gain in a plane wiggler with inhomogeneous magnetic field is calculated.. It is shown, that the account of inhomogenity of the magnetic field leads to appearance of additional peaks in the amplification

  16. Targeting helicase-dependent amplification products with an electrochemical genosensor for reliable and sensitive screening of genetically modified organisms. (United States)

    Moura-Melo, Suely; Miranda-Castro, Rebeca; de-Los-Santos-Álvarez, Noemí; Miranda-Ordieres, Arturo J; Dos Santos Junior, J Ribeiro; da Silva Fonseca, Rosana A; Lobo-Castañón, Maria Jesús


    Cultivation of genetically modified organisms (GMOs) and their use in food and feed is constantly expanding; thus, the question of informing consumers about their presence in food has proven of significant interest. The development of sensitive, rapid, robust, and reliable methods for the detection of GMOs is crucial for proper food labeling. In response, we have experimentally characterized the helicase-dependent isothermal amplification (HDA) and sequence-specific detection of a transgene from the Cauliflower Mosaic Virus 35S Promoter (CaMV35S), inserted into most transgenic plants. HDA is one of the simplest approaches for DNA amplification, emulating the bacterial replication machinery, and resembling PCR but under isothermal conditions. However, it usually suffers from a lack of selectivity, which is due to the accumulation of spurious amplification products. To improve the selectivity of HDA, which makes the detection of amplification products more reliable, we have developed an electrochemical platform targeting the central sequence of HDA copies of the transgene. A binary monolayer architecture is built onto a thin gold film where, upon the formation of perfect nucleic acid duplexes with the amplification products, these are enzyme-labeled and electrochemically transduced. The resulting combined system increases genosensor detectability up to 10(6)-fold, allowing Yes/No detection of GMOs with a limit of detection of ∼30 copies of the CaMV35S genomic DNA. A set of general utility rules in the design of genosensors for detection of HDA amplicons, which may assist in the development of point-of-care tests, is also included. The method provides a versatile tool for detecting nucleic acids with extremely low abundance not only for food safety control but also in the diagnostics and environmental control areas.

  17. 重组酶聚合酶扩增技术的研究进展%Advances in recombinase polymerase amplification

    Institute of Scientific and Technical Information of China (English)

    孙魁; 邢微微; 徐东刚


    重组酶聚合酶扩增技术(recombinase polymerase amplification,RPA),是Piepenburg 等于2006年首先提出的一种新型的恒温核酸扩增技术,其最显著的优势就是可在25~43℃的恒温下实现特定核酸序列的扩增,且能在5~20 min观察结果。 RPA技术设备要求低,扩增过程不仅可采用传统的反应管,还可在纸片等反应载体上进行。通过结合探针或横向流动试纸条( LFD)等方法,可实现扩增产物的定量分析或可视化判别。 RPA作为一种操作简便、反应快速、灵敏度高、特异性强、无需精密仪器的检测技术,是目前最有潜力成为快速分子诊断的工具,其在床旁诊断及防疫现场检测中都具有良好的应用前景。该文介绍了RPA技术在反应条件、产物检测等方面的优势及发展,总结了此技术近几年在实际应用中的情况,展望了RPA技术在床旁诊断及疾病防控中的未来方向。%Recombinase polymerase amplification (RPA) is a novel isothermal DNA amplification technology first re-ported in 2006 by Piepenburg et al.This technology has been shown to typically work at temperatures ranging from 25 to 43℃and can detect products within 5-20 min.RPA technology requires little instrumentation for the nucleic acid amplifi-cation reaction and can be performed not only in PCR tubes , but also in simple devices′such as paper .Combined with probe-based detection methods or lateral flow dipstick assay , it can perform quantitative or visual detection respectively . RPA is a technology that is potentially ideal for point-of-care diagnosis and disease prevention and control ,characterized by high sensitivity, high efficiency, high specificity and user-friendliness.This paper introduces the advantages and develop-ment of RPA technology in reaction conditions and product detection ,summarizes the current applications of this technolo-gy,and predicts the trend of application of RPA

  18. Competitive reporter monitored amplification (CMA--quantification of molecular targets by real time monitoring of competitive reporter hybridization.

    Directory of Open Access Journals (Sweden)

    Thomas Ullrich

    Full Text Available BACKGROUND: State of the art molecular diagnostic tests are based on the sensitive detection and quantification of nucleic acids. However, currently established diagnostic tests are characterized by elaborate and expensive technical solutions hindering the development of simple, affordable and compact point-of-care molecular tests. METHODOLOGY AND PRINCIPAL FINDINGS: The described competitive reporter monitored amplification allows the simultaneous amplification and quantification of multiple nucleic acid targets by polymerase chain reaction. Target quantification is accomplished by real-time detection of amplified nucleic acids utilizing a capture probe array and specific reporter probes. The reporter probes are fluorescently labeled oligonucleotides that are complementary to the respective capture probes on the array and to the respective sites of the target nucleic acids in solution. Capture probes and amplified target compete for reporter probes. Increasing amplicon concentration leads to decreased fluorescence signal at the respective capture probe position on the array which is measured after each cycle of amplification. In order to observe reporter probe hybridization in real-time without any additional washing steps, we have developed a mechanical fluorescence background displacement technique. CONCLUSIONS AND SIGNIFICANCE: The system presented in this paper enables simultaneous detection and quantification of multiple targets. Moreover, the presented fluorescence background displacement technique provides a generic solution for real time monitoring of binding events of fluorescently labelled ligands to surface immobilized probes. With the model assay for the detection of human immunodeficiency virus type 1 and 2 (HIV 1/2, we have been able to observe the amplification kinetics of five targets simultaneously and accommodate two additional hybridization controls with a simple instrument set-up. The ability to accommodate multiple controls

  19. The application of loop-mediated isothermal amplification for detection of common pathogenic bacteria in lower respiratory tract infections

    Institute of Scientific and Technical Information of China (English)



    Objective To investigate the spectrum of common pathogenic bacteria of low respiratory tract infection by loop-mediated isothermal amplification(LAMP)of nucleic acid test and to prove the clinical significance of this method.Methods A total of 289 qualified sputum samples from patients with lower respiratory tract infections in Fujian Province were detected by LAMP technique,and then the distribution of pathogenic bacteria was analyzed.The positive cases(the patients whose specific3

  20. Rapid ultrasonic isothermal amplification of DNA with multiplexed melting analysis – applications in the clinical diagnosis of sexually transmitted diseases. (United States)

    Xu, Gaolian; Gunson, Rory N; Cooper, Jonathan M; Reboud, Julien


    We describe a nucleic acid testing (NAT) platform for infectious disease diagnostics at the point-of-care, using surface acoustic waves (SAW) to perform a multiplexed loop-mediated isothermal amplification (LAMP) test for sexually transmitted diseases. The ultrasonic actuation not only enables faster NAT reactions but also provides a route towards integrating low-cost, low-power molecular diagnostics into disposable sensors.

  1. Human identification from forensic materials by amplification of a human-specific sequence in the myoglobin gene.


    Ono T; Miyaishi S; Yamamoto Y; Yoshitome K; Ishikawa T.; Ishizu H


    We developed a method for human identification of forensic biological materials by PCR-based detection of a human-specific sequence in exon 3 of the myoglobin gene. This human-specific DNA sequence was deduced from differences in the amino acid sequences of myoglobins between humans and other animal species. The new method enabled amplification of the target DNA fragment from 30 samples of human DNA, and the amplified sequences were identical with that already reported. Using this method, we ...

  2. Methods for microbial DNA extraction from soil for PCR amplification


    Yeates C; Gillings, MR; Davison AD; Altavilla N; Veal DA


    Amplification of DNA from soil is often inhibited by co-purified contaminants. A rapid, inexpensive, large-scale DNA extraction method involving minimal purification has been developed that is applicable to various soil types (1). DNA is also suitable for PCR amplification using various DNA targets. DNA was extracted from 100g of soil using direct lysis with glass beads and SDS followed by potassium acetate precipitation, polyethylene glycol precipitation, phenol extraction and isopropanol pr...

  3. Pulse Distortion in Saturated Fiber Optical Parametric Chirped Pulse Amplification

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Da Ros, Francesco; Rottwitt, Karsten


    Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation.......Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation....

  4. Aerosol Lidar for the Relative Backscatter Amplification Measurements (United States)

    Razenkov, Igor A.; Banakh, Victor A.; Nadeev, Alexander I.


    Backscatter amplification presents only in a turbulent atmosphere, when the laser beam is propagates twice through the same inhomogeneities. We proposed technical solution to detect backscatter amplification. An aerosol micro pulse lidar with a beam expansion via receiving telescope was built to study this effect. Our system allows simultaneous detection of two returns from the same scattering volume: exactly on the axis of the laser beam and off the axis.

  5. The emergence of surface-based Arctic amplification

    Directory of Open Access Journals (Sweden)

    M. C. Serreze


    Full Text Available Rises in surface and lower troposphere air temperatures through the 21st century are projected to be especially pronounced over the Arctic Ocean during the cold season. This Arctic amplification is largely driven by loss of the sea ice cover, allowing for strong heat transfers from the ocean to the atmosphere. Consistent with observed reductions in sea ice extent, fields from the NCEP/NCAR reanalysis suggest emergence of surface-based Arctic amplification in the last decade.

  6. Controllable Amplification of Entanglement for Two Qutrits under Decoherence

    Institute of Scientific and Technical Information of China (English)

    ZHENG Qiang; XIE Xiao-Yao; ZHI Qi-Jun; REN Zhong-Zhou


    Entanglement dynamics of a two-qutrit Heisenberg spin chain with the external magnetic fields and DM interaction under the intrinsic decoherence is investigated. Depending on whether there is inhomogeneous magnetic field,the entanglement amplification, i.e. the phenomenon that the finally stable entanglement is bigger than that of the initial one, is found for one kind of initial states. The reasons for the controllable entanglement amplification are discussed.

  7. Engineering targeted chromosomal amplifications in human breast epithelial cells. (United States)

    Springer, Simeon; Yi, Kyung H; Park, Jeenah; Rajpurohit, Anandita; Price, Amanda J; Lauring, Josh


    Chromosomal amplifications are among the most common genetic alterations found in human cancers. However, experimental systems to study the processes that lead to specific, recurrent amplification events in human cancers are lacking. Moreover, some common amplifications, such as that at 8p11-12 in breast cancer, harbor multiple driver oncogenes, which are poorly modeled by conventional overexpression approaches. We sought to develop an experimental system to model recurrent chromosomal amplification events in human cell lines. Our strategy is to use homologous-recombination-mediated gene targeting to deliver a dominantly selectable, amplifiable marker to a specified chromosomal location. We used adeno-associated virus vectors to target human MCF-7 breast cancer cells at the ZNF703 locus, in the recurrent 8p11-12 amplicon, using the E. coli inosine monophosphate dehydrogenase (IMPDH) enzyme as a marker. We applied selective pressure using IMPDH inhibitors. Surviving clones were found to have increased copy number of ZNF703 (average 2.5-fold increase) by droplet digital PCR and FISH. Genome-wide array comparative genomic hybridization confirmed that amplifications had occurred on the short arm of chromosome 8, without changes on 8q or other chromosomes. Patterns of amplification were variable and similar to those seen in primary human breast cancers, including "sawtooth" patterns, distal copy number loss, and large continuous regions of copy number gain. This system will allow study of the cis- and trans-acting factors that are permissive for chromosomal amplification and provide a model to analyze oncogene cooperativity in amplifications harboring multiple candidate driver genes.

  8. The emergence of surface-based Arctic amplification


    SERREZE, M. C.; A. P. Barrett; J. C. Stroeve; Kindig, D. N.; Holland, M. M.


    Rises in surface and lower troposphere air temperatures through the 21st century are projected to be especially pronounced over the Arctic Ocean during the cold season. This Arctic amplification is largely driven by loss of the sea ice cover, allowing for strong heat transfers from the ocean to the atmosphere. Consistent with observed reductions in sea ice extent, fields from both the NCEP/NCAR and JRA-25 reanalyses point to emergence of surface-based Arctic amplification in the last decade.

  9. Clinical significance of fluorescence in situ hybridization for detection of hTERC gene amplification in cervical cancer and precancerous tissues cases

    Directory of Open Access Journals (Sweden)

    Shuang LIU


    Full Text Available Objective  To detect the human telomerase RNA gene (hTERC amplification in cervical lesions, and explore its clinical significance. Methods  The tissues of the cervical lesions were collected from 195 patients, including 33 of chronic cervicitis, 34 of CINⅠ, 37 of CIN Ⅱ-Ⅲ, 30 of cervical squamous cell carcinoma, and 61 of cervica1 adenocarcinoma, and abnormal hTERC was detected with amplification of fluorescence in situhybridization (FISH. The relationship between hTERC gene amplification and clinicopathological parameters was analyzed. Results  Among the 195 patients, the positive rate of hTERC gene amplification was 3.03% (1/33, 29.41% (10/34, 72.97% (27/37, 100% (30/30, 91.8% (56/61 in chronic cervicitis, CINⅠ, CIN Ⅱ-Ⅲ, cervical squamous cell carcinoma and cervica1 adenocarcinoma respectively, and the results showed that hTERC amplification rate was significantly higher in group CIN Ⅱ-Ⅲthan in group CINⅠ(P 0.05. Conclusion  Detection of gene amplification by FISH technology can be used as a means for accurate diagnosis and prediction of the histologically difficult-to-diagnose lesion and for risk assessment after treatment of cervical precancerous lesions.

  10. 浓磷酸沉降与澄清技术的进展%Progress for Precipitation and Clarification Technologies of Concentrated Phosphoric Acid

    Institute of Scientific and Technical Information of China (English)



    Author has introduced the phosphoric acid plant with a capacity of 280 000 t/a in the Yuntianhua Yunfeng Sub-company, in allusion to go-ing down for phosphorus ore grade, impurity content was continuously increased,acid product quality was decreased with more fluctuation, therefore having formed the problem influencing downstream phosphoric compound fertilizer product , precipitation and clarification technologies were adopted for the con-centrated phosphoric acid, and the adding type for flocculent was changed.Result indicates that the solid content in concentrated phosphoric acid is aver-agely 0.917% during January to July month in 2013,it creates a condition for producing qualified DAP with a ratio of 18-46-0 .%介绍了云天化云峰分公司产能为28万t/a磷酸装置,针对磷矿品位的不断下降,杂质含量的不断升高,造成酸品质差,波动较大,从而影响到下游磷复肥产品的问题,采用了浓磷酸沉降与澄清技术,并改变絮凝剂加入方式。结果表明,2013年1~7月浓酸含固量平均为0.917%,为生产合格的18-46-0的DAP创造了条件。

  11. Targeting MET Amplification as a New Oncogenic Driver

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Hisato [Department of Medical Oncology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Okamoto, Isamu, E-mail: [Department of Medical Oncology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Center for Clinical and Translational Research, Kyushu University Hospital, 3-1-1 Maidashi, Higashiku, Fukuoka 812-8582 (Japan); Okamoto, Wataru [Department of Medical Oncology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Division of Transrlational Research, Exploratory Oncology Research & Clinical Trial Center, National Cancer Center, 6-5-1 Kashiwanoha, Kashiwa, Chiba 277-8577 (Japan); Tanizaki, Junko [Department of Medical Oncology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, HIM223, 450 Brookline Avenue, Boston, MA 02215 (United States); Nakagawa, Kazuhiko [Department of Medical Oncology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan); Nishio, Kazuto [Department of Genome Biology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511 (Japan)


    Certain genetically defined cancers are dependent on a single overactive oncogene for their proliferation and survival, a phenomenon known as “oncogene addiction”. A new generation of drugs that selectively target such “driver oncogenes” manifests a clinical efficacy greater than that of conventional chemotherapy in appropriate genetically defined patients. MET is a proto-oncogene that encodes a receptor tyrosine kinase, and aberrant activation of MET signaling occurs in a subset of advanced cancers as result of various genetic alterations including gene amplification, polysomy, and gene mutation. Our preclinical studies have shown that inhibition of MET signaling either with the small-molecule MET inhibitor crizotinib or by RNA interference targeted to MET mRNA resulted in marked antitumor effects in cancer cell lines with MET amplification both in vitro and in vivo. Furthermore, patients with non-small cell lung cancer or gastric cancer positive for MET amplification have shown a pronounced clinical response to crizotinib. Accumulating preclinical and clinical evidence thus suggests that MET amplification is an “oncogenic driver” and therefore a valid target for treatment. However, the prevalence of MET amplification has not been fully determined, possibly in part because of the difficulty in evaluating gene amplification. In this review, we provide a rationale for targeting this genetic alteration in cancer therapy.

  12. Targeting MET Amplification as a New Oncogenic Driver

    Directory of Open Access Journals (Sweden)

    Hisato Kawakami


    Full Text Available Certain genetically defined cancers are dependent on a single overactive oncogene for their proliferation and survival, a phenomenon known as “oncogene addiction”. A new generation of drugs that selectively target such “driver oncogenes” manifests a clinical efficacy greater than that of conventional chemotherapy in appropriate genetically defined patients. MET is a proto-oncogene that encodes a receptor tyrosine kinase, and aberrant activation of MET signaling occurs in a subset of advanced cancers as result of various genetic alterations including gene amplification, polysomy, and gene mutation. Our preclinical studies have shown that inhibition of MET signaling either with the small-molecule MET inhibitor crizotinib or by RNA interference targeted to MET mRNA resulted in marked antitumor effects in cancer cell lines with MET amplification both in vitro and in vivo. Furthermore, patients with non-small cell lung cancer or gastric cancer positive for MET amplification have shown a pronounced clinical response to crizotinib. Accumulating preclinical and clinical evidence thus suggests that MET amplification is an “oncogenic driver” and therefore a valid target for treatment. However, the prevalence of MET amplification has not been fully determined, possibly in part because of the difficulty in evaluating gene amplification. In this review, we provide a rationale for targeting this genetic alteration in cancer therapy.

  13. Influence of technological processes on phenolic compounds, organic acids, furanic derivatives, and antioxidant activity of whole-lemon powder. (United States)

    García-Salas, Patricia; Gómez-Caravaca, Ana María; Arráez-Román, David; Segura-Carretero, Antonio; Guerra-Hernández, Eduardo; García-Villanova, Belén; Fernández-Gutiérrez, Alberto


    The healthy properties of citrus fruits have been attributed to ascorbic acid and phenolic compounds, mainly to flavonoids. Flavonoids are important phytonutrients because they have a wide range of biological effects that provide health-related properties. In this context, this study seeks to characterise the phenolic compounds in lemon and their stability in different drying processes (freeze-drying and vacuum-drying) and storage conditions (-18 and 50°C for 1 and 3months). A powerful high-performance liquid chromatography coupled to DAD and electrospray-ionization time-of-flight mass spectrometry (HPLC-ESI-TOF-MS) method has been applied for the separation, identification, and quantification of 19 phenolic compounds and 4 organic acids. To our knowledge, two hydroxycinnamic acids have been identified for the first time in lemon. Folin-Ciocalteu was applied to determine total phenolic compounds and TEAC, FRAP, and ORAC were applied to determine the antioxidant capacity of lemon. Total phenolic content significantly differed in the samples analysed, vacuum-dried lemon showing the highest phenolic content, followed by freeze-dried lemon and, finally, vacuum-dried lemon stored at 50°C for 1 and 3months. The content in furanic compounds was determined to evaluate the heat damage in lemon and it was showed an increase with the thermal treatment because of the triggering of Maillard reaction. As exception of ORAC, antioxidant-capacity assays were not correlated to phenolic content by HPLC due to the formation of antioxidant compounds during Maillard reaction.

  14. Loop-Mediated Isothermal Amplification Method and Its Application in Pathogen Inspection%环介导等温扩增技术在病原菌检测中的应用

    Institute of Scientific and Technical Information of China (English)

    刘芳; 黄静敏; 何永盛; 李传礼


    Loop-mediated isothermal amplification (LAMP) is an established nucleic acid amplification method offering a rapid, accurate, and cost-effective diagnosis of infectious diseases. This technology has been developed for a variety of pathogens, including bacteria and viruses. The current focus on LAMP methodology is to explore LAMP as a diagnostic system in resource-limited laboratories in developing countries, where many fatal tropical diseases are endemic. The combination of LAMP and novel microfluidic technologies may facilitate the realization of genetic point-of-care testing systems to be used in the near future. This review described the historical, current, and future developments of such technologies.%环介导等温扩增是一种新的核酸扩增技术,具有简单、快速、特异性强的特点。针对多种食源性致病菌和病毒的环介导等温扩增检测方法已建立了起来,现在主要是发展成为发展中国家一些高发传染病的快速诊断方法,今后环介导等温扩增和微流体等技术的联用有望推动基因床边诊断的实现。本文针对环介导等温扩增技术过去、现在的应用和未来的发展方向展开了论述。

  15. 苦杏仁酸制备工艺研究%Study on Preparation Technology of Bitter Almond Acid

    Institute of Scientific and Technical Information of China (English)



    Using TEBA quaternary ammonium salt as phase transfer catalyst,the synthesis of bitter almond acid by using phenyl formaldehyde as raw material is a new synthetic method.Greatly accelerate the reaction speed improve the yield,but also simplifies the operation,instead of the previous by benzaldehyde and sodium cyanide addition to cyanohydrin then hydrolyzing the long route, inconvenient operation,labor protection requirements of the shortcomings of high.The specific effects of the experimental conditions on the synthesis of bitter almond acid were introduced,and the optimum conditions for the synthesis of bitter almond were found.%以TEBA季铵盐为相转移催化剂,苯甲醛为原料合成苦杏仁酸是一种新的合成方法。新的合成方法加快了反应速度提高了收率,也简化了操作,代替了以往多由苯甲醛与氰化钠加成得氰醇再水解制得的传统方法,克服了路线长,操作不便,劳动保护要求高的缺点。介绍了实验条件对合成苦杏仁酸反应的具体影响,找到了合成实验的最佳条件。

  16. Sebacic Acid and Industrial Production Technology%癸二酸与工业制取技术

    Institute of Scientific and Technical Information of China (English)



    由蓖麻油酸生产癸二酸,属于蓖麻油的第三代衍生产品,工业用途广而重要,文章对其物化性质、制取方法作了系统介绍,意在推动蓖麻种植、蓖麻油产业发展,为化学工业提供再生原料,并与油脂工作者同瞻蓖麻油的开发前景。%Originating from ricinoleic acid, sebacic acid belongs to the third generation derivatives of castor oil, whose industrial use is widely and important. In order to promote the development of castor plant and castor oil industry, this paper systematically introduces its physical and chemical properties, thus providing renewable raw materials for chemical industry, and looking forward future of castor oil with oil workers.

  17. Label-free thioflavin T/G-quadruplex-based real-time strand displacement amplification for biosensing applications. (United States)

    Du, Yi-Chen; Zhu, Li-Na; Kong, De-Ming


    To promote application of strand-displacement amplification (SDA) techniques in biosensing, a label-free, real-time monitoring strategy for isothermal nucleic acid amplification reactions was designed. G-quadruplex structures were introduced into SDA products using specific recognition of G-quadruplexes by the fluorogenic dye thioflavin T. Performance was good for real-time monitoring of traditional SDA by a linear-amplification mechanism and for exponential cross-triggered SDA amplification. The strategy worked on a commercial real-time PCR instrument, making it suitable for biosensing platforms. As examples, two highly sensitive and specific biosensors were designed for analysis of the activity of uracil-DNA glycosylase (UDG) and the restriction endonuclease EcoRI. Detection limits were 6×10(-5)U/mL for UDG and 0.016U/mL for EcoRI. Detection of corresponding targets in complex matrices such as cell lysates or human serum was also demonstrated. Compared to traditional end-point detection methods, real-time SDA-based approaches have the advantages of simple, fast operation; high sensitivity; low risk of carryover contamination; and very high throughput. The introduction of real-time monitoring strategies may promote application of SDA reactions in biosensor design.

  18. Continuous-flow ATP amplification system for increasing the sensitivity of quantitative bioluminescence assay. (United States)

    Satoh, Tetsuya; Shinoda, Yasuharu; Alexandrov, Maxym; Kuroda, Akio; Murakami, Yuji


    We constructed a novel ATP amplification reactor using a continuous-flow system, and this allowed us to increase the sensitivity of a quantitative bioluminescence assay by controlling the number of ATP amplification cycles. We previously developed a bioluminescence assay coupled with ATP amplification using a batch system. However, it was difficult to control the number of amplification cycles. In this study, ATP amplification was performed using a continuous-flow system, and significant linear correlations between amplified luminescence and initial ATP concentration were observed. When performing four cycles of continuous-flow ATP amplification, the gradient of amplification was 1.87(N). Whereas the lower quantifiable level was 500 pM without amplification, values as low as 50 pM ATP could be measured after amplification. The sensitivity thus increased 10-fold, with further improvements expected with additional amplification cycles. The continuous-flow system thus effectively increased the sensitivity of the quantitative bioluminescence assay.

  19. Metastatic basal cell carcinoma with amplification of PD-L1: exceptional response to anti-PD1 therapy (United States)

    Ikeda, Sadakatsu; Goodman, Aaron M; Cohen, Philip R; Jensen, Taylor J; Ellison, Christopher K; Frampton, Garrett; Miller, Vincent; Patel, Sandip P; Kurzrock, Razelle


    Metastatic basal cell carcinomas are rare malignancies harbouring Hedgehog pathway alterations targetable by SMO antagonists (vismodegib/sonidegib). We describe, for the first time, the molecular genetics and response of a patient with Hedgehog inhibitor-resistant metastatic basal cell carcinoma who achieved rapid tumour regression (ongoing near complete remission at 4 months) with nivolumab (anti-PD1 antibody). He had multiple hallmarks of anti-PD1 responsiveness including high mutational burden (> 50 mutations per megabase; 19 functional alterations in tissue next-generation sequencing (NGS; 315 genes)) as well as PDL1/PDL2/JAK2 amplification (as determined by both tissue NGS and by analysis of plasma-derived cell-free DNA). The latter was performed using technology originally developed for the genome-wide detection of sub-chromosomal copy-number alterations (CNAs) in noninvasive prenatal testing and showed numerous CNAs including amplification of the 9p24.3-9p22.2 region containing PD-L1, PD-L2 and JAK2. Of interest, PD-L1, PD-L2 and JAK2 amplification is a characteristic of Hodgkin lymphoma, which is exquisitely sensitive to nivolumab. In conclusion, selected SMO antagonist-resistant metastatic basal cell carcinomas may respond to nivolumab based on underlying molecular genetic mechanisms that include PD-L1 amplification and high tumour mutational burden. PMID:27942391

  20. Development of Rapid Isothermal Amplification Assays for Detection of Phytophthora spp. in Plant Tissue. (United States)

    Miles, Timothy D; Martin, Frank N; Coffey, Michael D


    Several isothermal amplification techniques recently have been developed that are tolerant of inhibitors present in many plant extracts, which can reduce the need for obtaining purified DNA for running diagnostic assays. One such commercially available technique that has similarities with real-time polymerase chain reaction (PCR) for designing primers and a labeled probe is recombinase polymerase amplification (RPA). This technology was used to develop two simple and rapid approaches for detection of Phytophthora spp.: one genus-specific assay multiplexed with a plant internal control and the other species-specific assays for Phytophthora ramorum and P. kernoviae. All assays were tested for sensitivity (ranging from 3 ng to 1 fg of DNA) and specificity using DNA extracted from more than 136 Phytophthora taxa, 21 Pythium spp., 1 Phytopythium sp., and a wide range of plant species. The lower limit of linear detection using purified DNA was 200 to 300 fg of DNA in all pathogen RPA assays. Six different extraction buffers were tested for use during plant tissue maceration and the assays were validated in the field by collecting 222 symptomatic plant samples from over 50 different hosts. Only 56 samples were culture positive for Phytophthora spp. whereas 91 were positive using the Phytophthora genus-specific RPA test and a TaqMan real-time PCR assay. A technique for the generation of sequencing templates from positive RPA amplifications to confirm species identification was also developed. These RPA assays have added benefits over traditional technologies because they are rapid (results can be obtained in as little as 15 min), do not require DNA extraction or extensive training to complete, use less expensive portable equipment than PCR-based assays, and are significantly more specific than current immunologically based methods. This should provide a rapid, field-deployable capability for pathogen detection that will facilitate point-of-sample collection processing

  1. Application of nucleic acid detection technology in blood screening of blood donors%核酸检测技术在献血人员血液筛查中的应用

    Institute of Scientific and Technical Information of China (English)

    柯苑; 赵静; 马成平; 黄敏; 姚慧兰; 张立波; 马贵明


    Objective To explore the value of nucleic acid detection technology (NAT ) for blood screening to decrease the infection induced by blood donors in the window period and infected insidiously .Methods A total of 54 358 blood samples were detected by ELISA for hepatitis B surface antigen (HBsAg) ,antibody of human immuno-deficiency virus (HIV-Ab ) ,antibody of hepatitis C virus (anti-HCV ) ,and transcription-mediated amplification (TMA)method were used to detecte the DNA of hepatitis B virus (HBV-DNA ) ,the RNA of hepatitis C virus (HCV-RNA)and the RNA of type 1 human immunodeficiency virus(HIV-1 RNA) .Results Fifty-one samples were positive by NAT ,but negative by ELISA .A total of 33 samples in these 51 samples were identified .The HBV-DNA of 32 donors were positive ,and the HIV-1 RNA of one donor was positive ,who was identified as suspected HIV-1 positive (gp160 and p24 ± ) by western blot method in Nanjing municipal center for disease control and prevention . Six months later ,this blood donor was identified as HIV-1 positive (gp160 ,gp120 ,p66 ,p51 ,gp41 ,p31 ,p24 ,p17 + ) by western blot method in Nanjing municipal center for disease control and prevention .Conclusion NAT could effec-tively decrease the infection induced by blood donors in the window period and infected insidiously ,so as to reduce the risk of blood transfusion .%目的:采取核酸检测(NAT )技术进行血液筛查,减少由献血者感染“窗口期”及隐匿感染献血引起的疾病传播。方法采用酶联免疫吸附法(ELISA)对54358份献血者标本进行乙型肝炎表面抗原(HBsAg)、人类免疫缺陷病毒抗体(抗-HIV)、丙型肝炎病毒抗体(HCV-Ab)检测,同时用转录介导扩增技术(TMA)进行 HBV-DNA 、HCV-RNA 检测,人类免疫缺陷病毒1型(HIV-1)RNA 核酸检测。结果 NAT 检测阳性 ELISA 检测阴性标本共51份。51份标本有鉴别试验结果的33份,其中32份 HBV-DNA 阳性,1份 HIV-1 RNA

  2. Amplification of thermostable lipase genes fragment from thermogenic phase of domestic waste composting process (United States)

    Nurhasanah, Nurbaiti, Santi; Madayanti, Fida; Akhmaloka


    Lipases are lipolytic enzymes, catalyze the hydrolysis of fatty acid ester bonds of triglycerides to produce free fatty acids and glycerol. The enzyme is widely used in various fields of biotechnological industry. Hence, lipases with unique properties (e.g.thermostable lipase) are still being explored by variation methods. One of the strategy is by using metagenomic approach to amplify the gene directly from environmental sample. This research was focused on amplification of lipase gene fragment directly from the thermogenic phase of domestic waste composting in aerated trenches. We used domestic waste compost from waste treatment at SABUGA, ITB for the sample. Total chromosomal DNA were directly extracted from several stages at thermogenic phase of compost. The DNA was then directly used as a template for amplification of thermostable lipase gene fragments using a set of internal primers namely Flip-1a and Rlip-1a that has been affixed with a GC clamp in reverse primer. The results showed that the primers amplified the gene from four stages of thermogenic phase with the size of lipase gene fragment of approximately 570 base pairs (bp). These results were further used for Denaturing Gradient Gel Electrophoresis (DGGE) analysis to determine diversity of thermostable lipase gene fragments.

  3. Direct ultrasensitive electrochemical biosensing of pathogenic DNA using homogeneous target-initiated transcription amplification (United States)

    Yan, Yurong; Ding, Shijia; Zhao, Dan; Yuan, Rui; Zhang, Yuhong; Cheng, Wei


    Sensitive and specific methodologies for detection of pathogenic gene at the point-of-care are still urgent demands in rapid diagnosis of infectious diseases. This work develops a simple and pragmatic electrochemical biosensing strategy for ultrasensitive and specific detection of pathogenic nucleic acids directly by integrating homogeneous target-initiated transcription amplification (HTITA) with interfacial sensing process in single analysis system. The homogeneous recognition and specific binding of target DNA with the designed hairpin probe triggered circular primer extension reaction to form DNA double-strands which contained T7 RNA polymerase promoter and served as templates for in vitro transcription amplification. The HTITA protocol resulted in numerous single-stranded RNA products which could synchronously hybridized with the detection probes and immobilized capture probes for enzyme-amplified electrochemical detection on the biosensor surface. The proposed electrochemical biosensing strategy showed very high sensitivity and selectivity for target DNA with a dynamic response range from 1 fM to 100 pM. Using salmonella as a model, the established strategy was successfully applied to directly detect invA gene from genomic DNA extract. This proposed strategy presented a simple, pragmatic platform toward ultrasensitive nucleic acids detection and would become a versatile and powerful tool for point-of-care pathogen identification.

  4. 柠檬酸生产废水处理技术%Technology for Treatment of Wastewater from Citric Acid Production

    Institute of Scientific and Technical Information of China (English)



    分析了柠檬酸生产废水的来源及水质特性,综述了厌氧生物法、厌氧-好氧生物组合法、乳状液膜法等在柠檬酸废水处理中的应用,介绍了中和废水回用和利用柠檬酸发酵废液开发糖化酶制剂的技术。%The sources and characteristics of the wastewater from citric acid production are described.The application of the treatment processes,such as anaerobic biological process,anaerobic-aerobic biological combined process,emulsion liquid membrane process in the treatment of the wastewater are reviewed.The technologies for recycling the neutralized wastewater and preparation of saccharifying enzyme from the spent fermentation liquor are presented.

  5. Performance and techno-economic assessment of several solid-liquid separation technologies for processing dilute-acid pretreated corn stover. (United States)

    Sievers, David A; Tao, Ling; Schell, Daniel J


    Solid-liquid separation of pretreated lignocellulosic biomass slurries is a critical unit operation employed in several different processes for production of fuels and chemicals. An effective separation process achieves good recovery of solute (sugars) and efficient dewatering of the biomass slurry. Dilute acid pretreated corn stover slurries were subjected to pressure and vacuum filtration and basket centrifugation to evaluate the technical and economic merits of these technologies. Experimental performance results were used to perform detailed process simulations and economic analysis using a 2000 tonne/day biorefinery model to determine differences between the various filtration methods and their process settings. The filtration processes were able to successfully separate pretreated slurries into liquor and solid fractions with estimated sugar recoveries of at least 95% using a cake washing process. A continuous vacuum belt filter produced the most favorable process economics.

  6. Utility of lab-on-a-chip technology for high-throughput nucleic acid and protein analysis

    DEFF Research Database (Denmark)

    Hawtin, Paul; Hardern, Ian; Wittig, Rainer


    On-chip electrophoresis can provide size separations of nucleic acids and proteins similar to more traditional slab gel electrophoresis. Lab-on-a-chip (LoaC) systems utilize on-chip electrophoresis in conjunction with sizing calibration, sensitive detection schemes, and sophisticated data analysis...... to achieve rapid analysis times (C systems to enable and augment systems biology investigations. RNA quality, as assessed by an RNA integrity number score, is compared to existing quality control (QC) measurements. High-throughput DNA analysis of multiplex PCR...... samples is used to stratify gene sets for disease discovery. Finally, the applicability of a high-throughput LoaC system for assessing protein purification is demonstrated. The improvements in workflow processes, speed of analysis, data accuracy and reproducibility, and automated data analysis...

  7. ASAP: Amplification, sequencing & annotation of plastomes

    Directory of Open Access Journals (Sweden)

    Folta Kevin M


    Full Text Available Abstract Background Availability of DNA sequence information is vital for pursuing structural, functional and comparative genomics studies in plastids. Traditionally, the first step in mining the valuable information within a chloroplast genome requires sequencing a chloroplast plasmid library or BAC clones. These activities involve complicated preparatory procedures like chloroplast DNA isolation or identification of the appropriate BAC clones to be sequenced. Rolling circle amplification (RCA is being used currently to amplify the chloroplast genome from purified chloroplast DNA and the resulting products are sheared and cloned prior to sequencing. Herein we present a universal high-throughput, rapid PCR-based technique to amplify, sequence and assemble plastid genome sequence from diverse species in a short time and at reasonable cost from total plant DNA, using the large inverted repeat region from strawberry and peach as proof of concept. The method exploits the highly conserved coding regions or intergenic regions of plastid genes. Using an informatics approach, chloroplast DNA sequence information from 5 available eudicot plastomes was aligned to identify the most conserved regions. Cognate primer pairs were then designed to generate ~1 – 1.2 kb overlapping amplicons from the inverted repeat region in 14 diverse genera. Results 100% coverage of the inverted repeat region was obtained from Arabidopsis, tobacco, orange, strawberry, peach, lettuce, tomato and Amaranthus. Over 80% coverage was obtained from distant species, including Ginkgo, loblolly pine and Equisetum. Sequence from the inverted repeat region of strawberry and peach plastome was obtained, annotated and analyzed. Additionally, a polymorphic region identified from gel electrophoresis was sequenced from tomato and Amaranthus. Sequence analysis revealed large deletions in these species relative to tobacco plastome thus exhibiting the utility of this method for structural and

  8. Rapid genome detection of Schmallenberg virus and bovine viral diarrhea virus by use of isothermal amplification methods and high-speed real-time reverse transcriptase PCR. (United States)

    Aebischer, Andrea; Wernike, Kerstin; Hoffmann, Bernd; Beer, Martin


    Over the past few years, there has been an increasing demand for rapid and simple diagnostic tools that can be applied outside centralized laboratories by using transportable devices. In veterinary medicine, such mobile test systems would circumvent barriers associated with the transportation of samples and significantly reduce the time to diagnose important infectious animal diseases. Among a wide range of available technologies, high-speed real-time reverse transcriptase quantitative PCR (RT-qPCR) and the two isothermal amplification techniques loop-mediated isothermal amplification (LAMP) and recombinase polymerase amplification (RPA) represent three promising candidates for integration into mobile pen-side tests. The aim of this study was to investigate the performance of these amplification strategies and to evaluate their suitability for field application. In order to enable a valid comparison, novel pathogen-specific assays have been developed for the detection of Schmallenberg virus and bovine viral diarrhea virus. The newly developed assays were evaluated in comparison with established standard RT-qPCR using samples from experimentally or field-infected animals. Even though all assays allowed detection of the target virus in less than 30 min, major differences were revealed concerning sensitivity, specificity, robustness, testing time, and complexity of assay design. These findings indicated that the success of an assay will depend on the integrated amplification technology. Therefore, the application-specific pros and cons of each method that were identified during this study provide very valuable insights for future development and optimization of pen-side tests.

  9. A continuous-flow ATP amplification system for increasing the sensitivity of quantitative bioluminescence assay


    Satoh, Tetsuya; Shinoda, Yasuharu; Alexandrov, Maxym; Kuroda, Akio; Murakami, Yuji


    We constructed a novel ATP amplification reactor using a continuous-flow system, and this allowed us to increase the sensitivity of quantitative bioluminescence assay by controlling the number of ATP amplification cycles. We previously developed a bioluminescence assay coupled with ATP amplification using a batch system. However, it was difficult to control the number of amplification cycles. In this study, ATP amplification was performed using a continuous-flow system, and significant linear...

  10. Regulation of ribosomal DNA amplification by the TOR pathway. (United States)

    Jack, Carmen V; Cruz, Cristina; Hull, Ryan M; Keller, Markus A; Ralser, Markus; Houseley, Jonathan


    Repeated regions are widespread in eukaryotic genomes, and key functional elements such as the ribosomal DNA tend to be formed of high copy repeated sequences organized in tandem arrays. In general, high copy repeats are remarkably stable, but a number of organisms display rapid ribosomal DNA amplification at specific times or under specific conditions. Here we demonstrate that target of rapamycin (TOR) signaling stimulates ribosomal DNA amplification in budding yeast, linking external nutrient availability to ribosomal DNA copy number. We show that ribosomal DNA amplification is regulated by three histone deacetylases: Sir2, Hst3, and Hst4. These enzymes control homologous recombination-dependent and nonhomologous recombination-dependent amplification pathways that act in concert to mediate rapid, directional ribosomal DNA copy number change. Amplification is completely repressed by rapamycin, an inhibitor of the nutrient-responsive TOR pathway; this effect is separable from growth rate and is mediated directly through Sir2, Hst3, and Hst4. Caloric restriction is known to up-regulate expression of nicotinamidase Pnc1, an enzyme that enhances Sir2, Hst3, and Hst4 activity. In contrast, normal glucose concentrations stretch the ribosome synthesis capacity of cells with low ribosomal DNA copy number, and we find that these cells show a previously unrecognized transcriptional response to caloric excess by reducing PNC1 expression. PNC1 down-regulation forms a key element in the control of ribosomal DNA amplification as overexpression of PNC1 substantially reduces ribosomal DNA amplification rate. Our results reveal how a signaling pathway can orchestrate specific genome changes and demonstrate that the copy number of repetitive DNA can be altered to suit environmental conditions.

  11. Loop-mediated isothermal amplification (LAMP): A novel rapid detection platform for pathogens. (United States)

    Li, Yanmei; Fan, Penghui; Zhou, Shishui; Zhang, Li


    Foodborne bacterial infections and diseases have been considered to be a major threat for public health in the worldwide. Increased incidence of human diseases caused by foodborne pathogens have been correlated with growing world population and mobility. Loop-mediated isothermal amplification (LAMP) has been regarded as an innovative gene amplification technology and emerged as an alternative to PCR-based methodologies in both clinical laboratory and food safety testing. Nowadays, LAMP has been applied to detection and identification on pathogens from microbial diseases, as it showed significant advantage in high sensitivity, specificity and rapidity. The high sensitivity of LAMP enables detection of the pathogens in sample materials even without time consuming sample preparation. An overview of LAMP mainly containing the development history, reaction principle and its application to four kind of foodborne pathogens detection are presented in this paper. As concluded, with the advantages of rapidity, simplicity, sensitivity, specificity and robustness, LAMP is capable of applications for clinical diagnosis as well as surveillance of infection diseases. Moreover, the main purpose of this paper is to provide theoretical basis for the clinical application of LAMP technology.

  12. Diversity and technological properties of predominant lactic acid bacteria from fermented cassava used for the preparation of Gari, a traditional African food. (United States)

    Kostinek, Melanie; Specht, Ingrid; Edward, Vinodh A; Schillinger, Ulrich; Hertel, Christian; Holzapfel, Wilhelm H; Franz, Charles M A P


    Traditional fermentation of cassava is dominated by a lactic acid bacteria (LAB) population. Fermentation is important for improving product flavour and aroma as well as safety, especially by reduction of its toxic cyanogenic glucosides. The production of Gari from cassava in Benin typically occurs on a household or small industrial scale, and consequently suffers from inconsistent product quality and may not always be safe for consumption. Therefore, the diversity of LAB from a typical cassava fermentation for the preparation of Gari, and their technologically relevant characteristics were investigated with a view towards selection of appropriate starter cultures. A total of 139 predominant strains isolated from fermenting cassava were identified using phenotypic tests and genotypic methods such as rep-PCR and RAPD-PCR. DNA-DNA hybridisation and sequencing of the 16S rRNA genes were done for selected strains. Lactobacillus plantarum was the most abundantly isolated species (54.6% of isolates), followed by Leuconostoc fallax (22.3%) and Lactobacillus fermentum (18.0%). Lactobacillus brevis, Leuconostoc pseudomesenteroides and Weissella paramesenteroides were sporadically isolated. The L. plantarum strains were shown to be better acid producers and capable of faster acid production than the L. fallax or L. fermentum strains. The incidence of beta-glucosidase (linamarase) activity was also highest among strains of this species. Production of antagonistic substances such as H2O2 and bacteriocins, however, was more common among L. fallax and L. fermentum strains. Strains of all three species were capable of utilising the indigestible sugars raffinose and stachyose. Therefore, a starter culture containing a mixture of strains from all three species was recommended.

  13. 蔬菜腌制及其乳酸菌技术的研究进展%Pickling Process of Vegetables and its Lactic Acid Bacteria Technology

    Institute of Scientific and Technical Information of China (English)

    吴祖芳; 赵永威; 翁佩芳


    Pickled vegetables processing is an important part of the vegetable processing industry. With the gradual deepening developing of lactic acid bacteria research and new technologies of agricultural products processing, one of the great research interests-was focused on the study of pickled vegetables process. In this paper, the microbial diversity, metabolite of lactic bacteria and flavor compound formation, the functional properties evaluations as well as the ferment starter application of pickled vegetables were elucidated among the domestic and foreign research progress. This can provide the references for technology development and research of pickled vegetables processing.%蔬菜腌制加工是蔬菜加工产业中的重要组成部分,随着农产品加工新技术及乳酸菌研究的逐步深入和发展,腌制蔬菜也成为一个新的研究热点.作者分析了国内外有关蔬菜腌制过程中微生态、乳酸菌的代谢及其蔬菜腌制风味发生机制、腌制蔬菜功能特性评价以及发酵剂开发等方面的研究进展,为蔬菜腌制技术的发展等提供参考.

  14. Magnetic Amplification by Magnetized Cosmic Rays in SNR Shocks

    CERN Document Server

    Riquelme, Mario A


    (Abridged) X-ray observations of synchrotron rims in supernova remnant (SNR) shocks show evidence of strong magnetic field amplification (a factor of ~100 between the upstream and downstream medium). This amplification may be due to plasma instabilities driven by shock-accelerated cosmic rays (CRs). One candidate is the cosmic ray current-driven (CRCD) instability (Bell 2004), caused by the electric current of large Larmor radii CRs propagating parallel to the upstream magnetic field. Particle-in-cell (PIC) simulations have shown that the back-reaction of the amplified field on CRs would limit the amplification factor of this instability to less than ~10 in galactic SNRs. In this paper, we study the possibility of further amplification driven near shocks by "magnetized" CRs, whose Larmor radii are smaller than the length scale of the field that was previously amplified by the CRCD instability. We find that additional amplification can occur due to a new instability, driven by the CR current perpendicular to t...

  15. Processes and impacts of Arctic amplification: A research synthesis (United States)

    Serreze, Mark C.; Barry, Roger G.


    The past decade has seen substantial advances in understanding Arctic amplification — that trends and variability in surface air temperature tend to be larger in the Arctic region than for the Northern Hemisphere or globe as a whole. We provide a synthesis of research on Arctic amplification, starting with a historical context and then addressing recent insights into processes and key impacts, based on analysis of the instrumental record, modeling studies, and paleoclimate reconstructions. Arctic amplification is now recognized as an inherent characteristic of the global climate system, with multiple intertwined causes operating on a spectrum of spatial and temporal scales. These include, but are not limited to, changes in sea ice extent that impact heat fluxes between the ocean and the atmosphere, atmospheric and oceanic heat transports, cloud cover and water vapor that alter the longwave radiation flux to the surface, soot on snow and heightened black carbon aerosol concentrations. Strong warming over the Arctic Ocean during the past decade in autumn and winter, clearly associated with reduced sea ice extent, is but the most recent manifestation of the phenomenon. Indeed, periods of Arctic amplification are evident from analysis of both warm and cool periods over at least the past three million years. Arctic amplification being observed today is expected to become stronger in coming decades, invoking changes in atmospheric circulation, vegetation and the carbon cycle, with impacts both within and beyond the Arctic.

  16. Amplification of Information by Photons and the Quantum Chernoff Bound (United States)

    Zwolak, Michael; Riedel, C. Jess; Zurek, Wojciech H.


    Amplification was regarded, since the early days of quantum theory, as a mysterious ingredient that endows quantum microstates with macroscopic consequences, key to the ``collapse of the wavepacket,'' and a way to avoid embarrassing problems exemplified by Schrödinger's cat. This bridge between the quantum microworld and the classical world of our experience was postulated ad hoc in the Copenhagen Interpretation. Quantum Darwinism views amplification as replication, in many copies, of information about quantum states. We show that such amplification is a natural consequence of a broad class of models of decoherence, including the photon environment we use to obtain most of our information. The resultant amplification is huge, proportional to # ξQCB . Here, #  is the environment size and ξQCB is the ``typical'' Quantum Chernoff Information, which quantifies the efficiency of the amplification. The information communicated though the environment is imprinted in the states of individual environment subsystems, e.g., in single photons, which document the transfer of information into the environment and result in the emergence of the classical world. See,

  17. Local seismic site amplification: effects of obliquely incident antiplane motions (United States)

    Cherid, D.; Hammoutene, M.; Tiliouine, B.; Berrah, M. K.


    Seismic site amplification studies are generally used to assess the effects of local geology and soil conditions on ground motion characteristics. Although extensive reviews on site amplification phenomena associated with stratigraphic effects can be found in the specialized literature, it should be pointed out that most of the practical applications have been limited to the study of vertically propagating shear horizontal (SH) waves, i.e., to the 1-D soil amplification problem. Furthermore, little attention, if any, has been devoted to the study of the effects of non-vertically incident SH waves on surface accelerograms and on the earthquake response of structures. In the present work, the study is extended to an investigation of 2-D site amplification of non-vertically propagating seismic shear waves in multilayered viscoelastic soil deposits. Sensitivity analyses of the effects of non-vertical incidence on site amplification functions are performed based on site geotechnical data collected from post-seismic investigations of the 1980 El-Asnam earthquake. Analytical results are discussed in terms of seismic site transfer functions, spectral ratios, surface acceleration time histories, and structural response spectra for different values of wave incidence angle. Both bedrock and rock outcropping cases are examined.

  18. Adaptive base-isolation of civil structures using variable amplification

    Institute of Scientific and Technical Information of China (English)

    Kenneth K. Walsh; Makola M. Abdullah


    Semi-active dampers are used in base-isolation to reduce the seismic response of civil engineering structures.In the present study, a new semi-active damping system using variable amplification will be investigated for adaptive baseisolation. It uses a novel variable amplification device (VAD) connected in series with a passive damper. The VAD is capable of producing multiple amplification factors, each corresponding to a different amplification state. Forces from the damper are amplified to the structure according to the current amplification state, which is selected via a semi-active control algorithm specifically tailored to the system's unique damping characteristics. To demonstrate the effectiveness of the VAD-damper system for adaptive base-isolation, numerical simulations are conducted for three and seven-story base-isolated buildings subject to both far and near-field ground motions. The results indicate that the system can achieve significant reductions in response compared to the base-isolated buildings with no damper. The proposed system is also found to perform well compared to a typical semi-active damper.

  19. Evaluating the displacement amplification factors of concentrically braced steel frames (United States)

    Mahmoudi, Mussa; Zaree, Mahdi


    According to seismic design codes, nonlinear performance of structures is considered during strong earthquakes. Seismic design provisions estimate the maximum roof and story drifts occurring during major earthquakes by amplifying the drifts computed from elastic analysis at the prescribed seismic force level with a displacement amplification factor. The present study tries to evaluate the displacement amplification factors of conventional concentric braced frames (CBFs) and buckling restrained braced frames (BRBFs). As such, static nonlinear (pushover) analysis and nonlinear dynamic time history analysis have been performed on the model buildings with single and double bracing bays, and different stories and brace configurations (chevron V, invert V, and X bracing). It is observed that the displacement amplification factors for BRBFs are higher than that of CBFs. Also, the number of bracing bays and height of buildings have a profound effect on the displacement amplification factors. The evaluated ratios between displacement amplification factors and response modification factors are from 1 to 1.12 for CBFs and from 1 to 1.4 for BRBFs.

  20. Modeling the amplification dynamics of human Alu retrotransposons.

    Directory of Open Access Journals (Sweden)

    Dale J Hedges


    Full Text Available Retrotransposons have had a considerable impact on the overall architecture of the human genome. Currently, there are three lineages of retrotransposons (Alu, L1, and SVA that are believed to be actively replicating in humans. While estimates of their copy number, sequence diversity, and levels of insertion polymorphism can readily be obtained from existing genomic sequence data and population sampling, a detailed understanding of the temporal pattern of retrotransposon amplification remains elusive. Here we pose the question of whether, using genomic sequence and population frequency data from extant taxa, one can adequately reconstruct historical amplification patterns. To this end, we developed a computer simulation that incorporates several known aspects of primate Alu retrotransposon biology and accommodates sampling effects resulting from the methods by which mobile elements are typically discovered and characterized. By modeling a number of amplification scenarios and comparing simulation-generated expectations to empirical data gathered from existing Alu subfamilies, we were able to statistically reject a number of amplification scenarios for individual subfamilies, including that of a rapid expansion or explosion of Alu amplification at the time of human-chimpanzee divergence.

  1. Somatic recombination, gene amplification and cancer. (United States)

    Ramel, C; Cederberg, H; Magnusson, J; Vogel, E; Natarajan, A T; Mullender, L H; Nivard, J M; Parry, J M; Leyson, A; Comendador, M A; Sierra, L M; Ferreiro, J A; Consuegra, S


    The principle objective of this research programme, to analyse chemical induction of somatic recombination and related endpoints, i.e., mobilization of transposing elements and gene amplification, has been approached by means of several assay systems. These have included Drosophila, Saccharomyces and mammalian cell cultures. 6.1. Screening assays for mitotic recombination. A large number of chemicals have been investigated in the three Drosophila assay systems employed--the multiple wing hair/flare wing spot system developed by Graf et al., 1984, the white-ivory system developed by Green et al., 1986 and the white/white+ eye spot assay developed by Vogel (Vogel and Nivard, 1993). Particularly the screening of 181 chemicals, covering a wide array of chemical classes, by the last mentioned assay has shown that measurement of somatic recombination in Drosophila constitutes a sensitive and efficient short-term test which shows a remarkably good correlation with the agent score of 83 short-term tests analysed by ICPEMC (Mendelsohn et al., 1992; Table 2) as well as the assay performance in international collaborative programmes measuring carcinogen/non-carcinogens (de Serres and Ashby, 1981; Ashby et al., 1985, 1988). Also the wing spot assay has gained wide international recognition as a similarly sensitive test. These two assay systems in Drosophila measure both intrachromosomal events and interchromosomal recombination. The white-ivory system on the other hand is based on the loss of a tandem duplication in the white locus, the mechanism of which is less known, but probably involves intrachromosomal recombination. The difference in the mechanism between this assay and the former two was indicated by the lack of response to methotrexate in the white-ivory assay, while this compound was strongly recombinogenic in both the wing spot and white/white+ assays. The use of different strains of Drosophila with the white/white+ assay demonstrated the importance of the


    Institute of Scientific and Technical Information of China (English)

    Wang Haibin


    The real-time PCR technique for detection and quantification of hepatitis B virus DNA has been used broadly in clinic diagnosis in the world ,especially in china. But the HBV DNA used in amplification must be extracted by many steps of tube to tube, repeating washes centrifugations and other operations, such as Phenol-chloroform, Guanidinium thiocyanate (GuSCN)-silica and QIAamp, which was time-consuming and labor intensive and increased the risk of contamination and inaccurate results.

  3. Study on the Production Technology of Cheese by Acid Coagulation%酸凝奶酪生产工艺研究

    Institute of Scientific and Technical Information of China (English)

    付香斌; 宋淑红; 王明道


    [Objective] The research aimed to develop a simulated chess with lactic acid as coagulator. [ Method] The process flow of this experiment was:raw milk→pasteurization→cooling→adding lactic acid starter→insulated fermentation→adding lactic acid→milk coagulation→discharge whey→filtration→pressing→molding. The quality testing of produced cheese was carried out according to the requirement of national standard GB5421 -85. [Result] The cheese produced with lactic acid as coagulator was milk -white,tasted moderately sour,heavy milk fragrant, refined and soft and showed plasticity and it got 89 scores in comprehensive sensory evaluation. The lactic acid should be added slowly and stirring should be continuous to make pH value of the whole environment be uniform. As the addition of lactic acid was increased, the milk coagulation effect of cheese was better and better,but when the addition exceeded 0.17% ,the milk coagulation effect of cheese was becoming worse. The coagulation effect of cheese was best at 42 ℃. [ Conclusion ] It was feasible to produce cheese with lactic acid as coagulator and its optimum technological condition was as follows :0.17% lactic acid was added as coagulator, the milk coagulation temperature and time were 42 ℃ and 4 h.%[目的]开发一种以乳酸为凝结剂的模拟干酪.[方法]该试验的工艺流程为:原料乳→巴氏杀菌→冷却→添加发酵剂→保温发酵→加酸→凝乳→排乳清→过滤→压榨→成型,干酪质量检测按照国家标准GB5421-85进行.[结果]以乳酸为凝结剂生产的奶酪,呈乳白色,酸味适中,奶香浓郁,口感细腻柔软,有可塑性,综合感官评分为89分.要缓慢加入乳酸并不断搅拌,以使整个环境的pH均匀一致,随着乳酸添加量的增加,干酪的凝乳效果越来越好,但超过0.17%时干酪凝乳状态又呈下降趋势.42℃下干酪的凝结效果最好.[结论]以乳酸为凝结剂生产奶酪是可行的,其最佳生产工

  4. Novel degenerate PCR method for whole genome amplification applied to Peru Margin (ODP Leg 201 subsurface samples

    Directory of Open Access Journals (Sweden)

    Amanda eMartino


    Full Text Available A degenerate PCR-based method of whole-genome amplification, designed to work fluidly with 454 sequencing technology, was developed and tested for use on deep marine subsurface DNA samples. The method, which we have called Random Amplification Metagenomic PCR (RAMP, involves the use of specific primers from Roche 454 amplicon sequencing, modified by the addition of a degenerate region at the 3’ end. It utilizes a PCR reaction, which resulted in no amplification from blanks, even after 50 cycles of PCR. After efforts to optimize experimental conditions, the method was tested with DNA extracted from cultured E. coli cells, and genome coverage was estimated after sequencing on three different occasions. Coverage did not vary greatly with the different experimental conditions tested, and was around 62% with a sequencing effort equivalent to a theoretical genome coverage of 14.10X. The GC content of the sequenced amplification product was within 2% of the predicted values for this strain of E. coli. The method was also applied to DNA extracted from marine subsurface samples from ODP Leg 201 site 1229 (Peru Margin, and results of a taxonomic analysis revealed microbial communities dominated by Proteobacteria, Chloroflexi, Firmicutes, Euryarchaeota, and Crenarchaeota, among others. These results were similar to those obtained previously for those samples; however, variations in the proportions of taxa show that community analysis can be sensitive to both the amplification technique used and the method of assigning sequences to taxonomic groups. Overall, we find that RAMP represents a valid methodology for amplifying metagenomes from low biomass samples.

  5. Measurement-based noiseless linear amplification for quantum communication (United States)

    Chrzanowski, H. M.; Walk, N.; Haw, J. Y.; Thearle, O.; Assad, S. M.; Janousek, J.; Hosseini, S.; Ralph, T. C.; Symul, T.; Lam, P. K.


    Entanglement distillation is an indispensable ingredient in extended quantum communication networks. Distillation protocols are necessarily non-deterministic and require non-trivial experimental techniques such as noiseless amplification. We show that noiseless amplification could be achieved by performing a post-selective filtering of measurement outcomes. We termed this protocol measurement-based noiseless linear amplification (MBNLA). We apply this protocol to entanglement that suffers transmission loss of up to the equivalent of 100km of optical fibre and show that it is capable of distilling entanglement to a level stronger than that achievable by transmitting a maximally entangled state through the same channel. We also provide a proof-of-principle demonstration of secret key extraction from an otherwise insecure regime via MBNLA. Compared to its physical counterpart, MBNLA not only is easier in term of implementation, but also allows one to achieve near optimal probability of success.

  6. Linear Amplification of Optical Signal in Coupled Photonic Crystal Waveguides

    CERN Document Server

    Jandieri, Vakhtang


    We introduce a weakly coupled photonic crystal waveguide as a promising and realistic model for all-optical amplification. A symmetric pillar type coupled photonic crystal waveguide consisting of dielectric rods periodically distributed in a free space is proposed as all-optical amplifier. Using the unique features of the photonic crystals to control and guide the light, we have properly chosen the frequency at which only one mode (odd mode) becomes the propagating mode in the coupled photonic crystal waveguide, whereas another mode (even mode) is completely reflected from the guiding structure. Under this condition, the all-optical amplification is fully realized. The amplification coefficient for the continuous signal and the Gaussian pulse is calculated.

  7. Determining Parameters for Images Amplification by Pulses Interpolation

    Directory of Open Access Journals (Sweden)

    Morera-Delfín Leandro


    Full Text Available This paper presents the implementation of a method for image samples interpolation based on a physical scanning model. It uses the theory to take digital image samples and to perform an implementation of such mechanism through software. This allows us to get the appropriate parameters for the images amplification using a truncated sampler arrangement. The shown process copies the physical model of image acquisition in order to incorporate the required samples for the amplification. This process is useful in the reconstruction of details in low resolution images and for images compression. The proposed method studies the conservation of high frequency in the high resolution plane for the generation of the amplification kernel. A new way of direct application of the physical model for scanning images in analytic mode is presented.

  8. An Intrinsically Digital Amplification Scheme for Hearing Aids

    Directory of Open Access Journals (Sweden)

    Brenton R. Steele


    Full Text Available Results for linear and wide-dynamic range compression were compared with a new 64-channel digital amplification strategy in three separate studies. The new strategy addresses the requirements of the hearing aid user with efficient computations on an open-platform digital signal processor (DSP. The new amplification strategy is not modeled on prior analog strategies like compression and linear amplification, but uses statistical analysis of the signal to optimize the output dynamic range in each frequency band independently. Using the open-platform DSP processor also provided the opportunity for blind trial comparisons of the different processing schemes in BTE and ITE devices of a high commercial standard. The speech perception scores and questionnaire results show that it is possible to provide improved audibility for sound in many narrow frequency bands while simultaneously improving comfort, speech intelligibility in noise, and sound quality.

  9. The efficiency of magnetic field amplification at shocks by turbulence (United States)

    Ji (), Suoqing; Oh, S. Peng; Ruszkowski, M.; Markevitch, M.


    Turbulent dynamo field amplification has often been invoked to explain the strong field strengths in thin rims in supernova shocks ( ˜ 100 μG) and in radio relics in galaxy clusters ( ˜ μG). We present high-resolution magnetohydrodynamic simulations of the interaction between pre-shock turbulence, clumping and shocks, to quantify the conditions under which turbulent dynamo amplification can be significant. We demonstrate numerically converged field amplification which scales with Alfvén Mach number, B/B_0 ∝ M_A, up to M_A ˜ 150. This implies that the post-shock field strength is relatively independent of the seed field. Amplification is dominated by compression at low M_A, and stretching (turbulent amplification) at high M_A. For high M_A, the B-field grows exponentially and saturates at equipartition with turbulence, while the vorticity jumps sharply at the shock and subsequently decays; the resulting field is orientated predominately along the shock normal (an effect only apparent in 3D and not 2D). This agrees with the radial field bias seen in supernova remnants. By contrast, for low M_A, field amplification is mostly compressional, relatively modest, and results in a predominantly perpendicular field. The latter is consistent with the polarization seen in radio relics. Our results are relatively robust to the assumed level of gas clumping. Our results imply that the turbulent dynamo may be important for supernovae, but is only consistent with the field strength, and not geometry, for cluster radio relics. For the latter, this implies strong pre-existing B-fields in the ambient cluster outskirts.

  10. Identification of genetic elements associated with EPSPs gene amplification.

    Directory of Open Access Journals (Sweden)

    Todd A Gaines

    Full Text Available Weed populations can have high genetic plasticity and rapid responses to environmental selection pressures. For example, 100-fold amplification of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS gene evolved in the weed species Amaranthus palmeri to confer resistance to glyphosate, the world's most important herbicide. However, the gene amplification mechanism is unknown. We sequenced the EPSPS gene and genomic regions flanking EPSPS loci in A. palmeri, and searched for mobile genetic elements or repetitive sequences. The EPSPS gene was 10,229 bp, containing 8 exons and 7 introns. The gene amplification likely proceeded through a DNA-mediated mechanism, as introns exist in the amplified gene copies and the entire amplified sequence is at least 30 kb in length. Our data support the presence of two EPSPS loci in susceptible (S A. palmeri, and that only one of these was amplified in glyphosate-resistant (R A. palmeri. The EPSPS gene amplification event likely occurred recently, as no sequence polymorphisms were found within introns of amplified EPSPS copies from R individuals. Sequences with homology to miniature inverted-repeat transposable elements (MITEs were identified next to EPSPS gene copies only in R individuals. Additionally, a putative Activator (Ac transposase and a repetitive sequence region were associated with amplified EPSPS genes. The mechanism controlling this DNA-mediated amplification remains unknown. Further investigation is necessary to determine if the gene amplification may have proceeded via DNA transposon-mediated replication, and/or unequal recombination between different genomic regions resulting in replication of the EPSPS gene.

  11. Gene amplification: developments, and applications for medical diagnostics. January 1985-February 1989 (Citations from the Biobusiness data base). Report for January 1985-February 1989

    Energy Technology Data Exchange (ETDEWEB)


    This bibliography contains citations concerning genetic amplification, a revolutionary new DNA probe technology. Companies on the cutting edge of this technology are discussed, and mention is made of their licensing agreements. Applications in clinical diagnosis for such diseases as acquired immune deficiency syndrome and leukemia, and applications for prenatal testing, and forensic testing are examined. (Contains 55 citations fully indexed and including a title list.)

  12. Incorporating Novel Mobile Health Technologies Into Management of Knee Osteoarthritis in Patients Treated With Intra-Articular Hyaluronic Acid: Rationale and Protocol of a Randomized Controlled Trial (United States)

    Skrepnik, Nebojsa; Toselli, Richard M; Leroy, Bruno


    Background Osteoarthritis (OA) of the knee is one of the leading causes of disability in the United States. One relatively new strategy that could be helpful in the management of OA is the use of mHealth technologies, as they can be used to increase physical activity and promote exercise, which are key components of knee OA management. Objective Currently, no published data on the use of a mHealth approach to comprehensively monitor physical activity in patients with OA are available, and similarly, no data on whether mHealth technologies can impact outcomes are available. Our objective is to evaluate the effectiveness of mHealth technology as part of a tailored, comprehensive management strategy for patients with knee OA. Methods The study will assess the impact of a smartphone app that integrates data from a wearable activity monitor (thereby both encouraging changes in mobility as well as tracking them) combined with education about the benefits of walking on patient mobility. The results from the intervention group will be compared with data from a control group of individuals who are given the same Arthritis Foundation literature regarding the benefits of walking and wearable activity monitors but who do not have access to the data from those monitors. Activity monitors will capture step count estimates and will compare those with patients’ step goals, calories burned, and distance walked. Patients using the novel smartphone app will be able to enter information on their daily pain, mood, and sleep quality. The relationships among activity and pain, activity and mood, and sleep will be assessed, as will patient satisfaction with and adherence to the mobile app. Results We present information on an upcoming trial that will prospectively assess the ability of a mobile app to improve mobility for knee OA patients who are treated with intra-articular hyaluronic acid. Conclusions We anticipate the results of this study will support the concept that m

  13. Rapid detection of sacbrood virus (SBV by one-step reverse transcription loop-mediated isothermal amplification assay

    Directory of Open Access Journals (Sweden)

    Jin-Long Yang


    Full Text Available Abstract Background Sacbrood virus (SBV primarily infects honeybee broods, and in order to deal with the problem cost effective detection methods are required. Findings A one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP assay was developed for the rapid identification of SBV. The data demonstrated that, in a simple water bath, SBV RNA could be detected as early as 20 min at 65°C, and a positive amplification reaction was visible to the naked eye due to a color change brought on by the addition of nucleic acid stain SYBR Green. Conclusions The current study presents a method for the rapid and simple detection of SBV by RT-LAMP with high sensitivity and analytic specificity.

  14. High accuracy genotyping directly from genomic DNA using a rolling circle amplification based assay

    Directory of Open Access Journals (Sweden)

    Du Yuefen


    Full Text Available Abstract Background Rolling circle amplification of ligated probes is a simple and sensitive means for genotyping directly from genomic DNA. SNPs and mutations are interrogated with open circle probes (OCP that can be circularized by DNA ligase when the probe matches the genotype. An amplified detection signal is generated by exponential rolling circle amplification (ERCA of the circularized probe. The low cost and scalability of ligation/ERCA genotyping makes it ideally suited for automated, high throughput methods. Results A retrospective study using human genomic DNA samples of known genotype was performed for four different clinically relevant mutations: Factor V Leiden, Factor II prothrombin, and two hemochromatosis mutations, C282Y and H63D. Greater than 99% accuracy was obtained genotyping genomic DNA samples from hundreds of different individuals. The combined process of ligation/ERCA was performed in a single tube and produced fluorescent signal directly from genomic DNA in less than an hour. In each assay, the probes for both normal and mutant alleles were combined in a single reaction. Multiple ERCA primers combined with a quenched-peptide nucleic acid (Q-PNA fluorescent detection system greatly accellerated the appearance of signal. Probes designed with hairpin structures reduced misamplification. Genotyping accuracy was identical from either purified genomic DNA or genomic DNA generated using whole genome amplification (WGA. Fluorescent signal output was measured in real time and as an end point. Conclusions Combining the optimal elements for ligation/ERCA genotyping has resulted in a highly accurate single tube assay for genotyping directly from genomic DNA samples. Accuracy exceeded 99 % for four probe sets targeting clinically relevant mutations. No genotypes were called incorrectly using either genomic DNA or whole genome amplified sample.

  15. Theory of light amplification in active fishnet metamaterials

    CERN Document Server

    Hamm, Joachim M; Tsakmakidis, Kosmas L; Hess, Ortwin


    We establish a theory that traces light amplification in an active double-fishnet metamaterial back to its microscopic origins. Based on ab initio calculations of the light/plasmon fields we extract energy rates and conversion efficiencies associated with gain/loss channels directly from Poynting's theorem. We find that for the negative refactive index mode both radiative loss and gain outweigh resistive loss by more than a factor of two, opening a broad window of steady-state amplification (free of instabilities) accessible even when a gain reduction close to the metal is taken into account.

  16. High-frequency electric field amplification in a magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, Aleksandr V [Russian Research Centre ' Kurchatov Institute' , Moscow (Russian Federation)


    In the investigation of cyclotron ion heating in systems designed for plasma isotope separation, the high-frequency (HF) electric field amplification effect was found to occur in equilibrium plasma. In the present article this effect is treated as a result of the interaction of the plasma placed in a constant external magnetic field with the HF modes of the vacuum chamber. Consistent elaboration of this approach allowed obtaining a clear interpretation of the HF electric field amplification effect and constructing a simple model of HF field excitation in a plasma column embedded in the external magnetic field. (methodological notes)

  17. Exponential quadruplex priming amplification for DNA-based isothermal diagnostics. (United States)

    Partskhaladze, Tamar; Taylor, Adam; Lomidze, Levan; Gvarjaladze, David; Kankia, Besik


    Polymerase chain reaction (PCR) is a method of choice for molecular diagnostics. However, PCR relies on thermal cycling, which is not compatible with the goals of point-of-care diagnostics. A simple strategy to turn PCR into an isothermal method would be to use specific primers, which upon polymerase elongation can self-dissociate from the primer-binding sites. We recently demonstrated that a monomolecular DNA quadruplex, GGGTGGGTGGGTGGG, meets these requirements, which led to the development of the linear versions of quadruplex priming amplification (QPA). Here we demonstrate exponential version of isothermal QPA, which allows an unprecedented 10(10)-fold amplification of DNA signal in less than 40 min.

  18. Methods for microbial DNA extraction from soil for PCR amplification

    Directory of Open Access Journals (Sweden)

    Yeates C


    Full Text Available Amplification of DNA from soil is often inhibited by co-purified contaminants. A rapid, inexpensive, large-scale DNA extraction method involving minimal purification has been developed that is applicable to various soil types (1. DNA is also suitable for PCR amplification using various DNA targets. DNA was extracted from 100g of soil using direct lysis with glass beads and SDS followed by potassium acetate precipitation, polyethylene glycol precipitation, phenol extraction and isopropanol precipitation. This method was compared to other DNA extraction methods with regard to DNA purity and size.

  19. The emergence of surface-based Arctic amplification

    Directory of Open Access Journals (Sweden)

    M. C. Serreze


    Full Text Available Rises in surface and lower troposphere air temperatures through the 21st century are projected to be especially pronounced over the Arctic Ocean during the cold season. This Arctic amplification is largely driven by loss of the sea ice cover, allowing for strong heat transfers from the ocean to the atmosphere. Consistent with observed reductions in sea ice extent, fields from both the NCEP/NCAR and JRA-25 reanalyses point to emergence of surface-based Arctic amplification in the last decade.

  20. Influence of environmental noise on the weak value amplification (United States)

    Zhu, Xuannmin; Zhang, Yu-Xiang


    Quantum systems are always disturbed by environmental noise. We have investigated the influence of the environmental noise on the amplification in weak measurements. Three typical quantum noise processes are discussed in this article. The maximum expectation values of the observables of the measuring device decrease sharply with the strength of the depolarizing and phase damping channels, while the amplification effect of weak measurement is immune to the amplitude damping noise. To obtain significantly amplified signals, we must ensure that the preselection quantum systems are kept away from the depolarizing and phase damping processes.

  1. Ultra-broad bandwidth parametric amplification at degeneracy. (United States)

    Limpert, J; Aguergaray, C; Montant, S; Manek-Hönninger, I; Petit, S; Descamps, D; Cormier, E; Salin, F


    We report on a novel approach of ultra-broad bandwidth parametric amplification around degeneracy. A bandwidth of up to 400 nm centered around 800 nm is amplified in a BBO crystal by using chirped pump pulses with a bandwitdth as broad as 10 nm. A supercontinuum signal is generated in a microstructured fiber, having to first order a quadratic chirp, which is necessary to ensure temporal overlap of the interacting waves over this broad bandwidth. Furthermore, we discuss the potential of this approach for an octave-spanning parametric amplification.

  2. Raman amplification in the broken-wave regime

    CERN Document Server

    Farmer, John P


    In regimes far beyond the wavebreaking theshold of Raman amplification, we show that significant amplifcation can occur after the onset of wavebreaking, before phase mixing destroys the coupling between pump and probe. The amplification efficiency in this regime is therefore strongly dependent on the energy-transfer rate when wavebreaking occurs, and is, as such, sensitive to both the probe amplitude and profile. In order to access the higher-efficiency broken-wave regime, a short, intense probe is required. Parameter scans show the marked difference in behaviour compared to below wavebreaking, where longer, more energetic pulses lead to improved efficiencies.

  3. Amplification of maximally-path-entangled number states (United States)

    Agarwal, G. S.; Chaturvedi, S.; Rai, Amit


    We examine the behavior of a non-Gaussian state like the maximally path-entangled number state commonly known as a N00N state under phase-insensitive amplification. We derive an analytical result for the density matrix of the N00N state for arbitrary gain of the amplifier. We consider cases of both symmetric and antisymmetric amplification of the two modes of the N00N state. We quantitatively evaluate the loss of entanglement by the amplifier in terms of the logarithmic negativity parameter. We find that N00N states are more robust than their Gaussian counterparts.

  4. 杏皮渣醋醋酸发酵工艺条件的研究%Optimization of Technology Conditions for Acetic Acid Fermentation of Apricot Dregs Vinegar

    Institute of Scientific and Technical Information of China (English)

    张富县; 王文文; 李丽; 傅力


    为了提高杏皮渣醋醋酸发酵产量,对杏皮渣醋醋酸发酵工艺进行优化,采用均匀设计对杏皮渣醋醋酸发酵阶段中初始pH 值、初始酒精度、装瓶量、接种量、发酵时间和发酵温度进行优化,并建立二次多项式回归模型。结果表明:初始pH 值为4.24,初始酒精度为6.53%(V/V),装瓶量为30%,接种量为12.92%,发酵时间为25天,发酵温度为30.1℃,杏皮渣醋的产酸量可达到8.11%。在最优条件的基础上简化操作,在 pH 自然,接种量为13%,装瓶量为30%的条件下,采用静止发酵法30℃发酵24天,产酸量达到7.49 g/dL,占预测值的92.36%。%In order to improve the production of acetic acid fermentation,the technical parameters for acetic acid fermentation of apricot dregs vinegar are optimized by uniform design.The effects of initial pH,initial alcohol content,bottle capacity,inoculums,fermentation time and fermentation tempera-ture on acetic acid yield are studied.The regression equation of six factors to acetic acid yield is found. The results are as follows:initial pH of 4.24,initial alcohol content of 6.53% (V/V),bottle capacity of 30%,inoculums of 12.92%,fermentation time of 25 days and fermentation temperature of 30.1 ℃.In this case,the acetic acid yield reaches 8.11%.The technology conditions could be simpli-fied in the optimal conditions:they are natural pH,inoculums of 13%,which is 92.36% of the pre-dicted value,the bottle capacity of 30%.The acetic acid yield reaches 7.49 g/dL at 30 ℃for 24 days.

  5. Tuberculosis Biomarker Extraction and Isothermal Amplification in an Integrated Diagnostic Device. (United States)

    Creecy, Amy; Russ, Patricia K; Solinas, Francesca; Wright, David W; Haselton, Frederick R


    In this study, we integrated magnetic bead-based sample preparation and isothermal loop mediated amplification (LAMP) of TB in a single tube. Surrogate sputum samples produced by the Program for Appropriate Technology in Health containing inactivated TB bacteria were used to test the diagnostic. In order to test the sample preparation method, samples were lysed, and DNA was manually extracted and eluted into water in the tube. In a thermal cycler, LAMP amplified TB DNA from 103 TB cells/mL of sputum at 53.5 ± 3.3 minutes, 104 cells/mL at 46.3 ± 2.2 minutes, and 105 cells/mL at 41.6 ± 1.9 minutes. Negative control samples did not amplify. Next, sample preparation was combined with in-tubing isothermal LAMP amplification by replacing the water elution chamber with a LAMP reaction chamber. In this intermediate configuration, LAMP amplified 103 cells/mL at 74 ± 10 minutes, 104 cells/mL at 60 ± 9 minutes, and 105 TB cells/mL of sputum at 54 ± 9 minutes. Two of three negative controls did not amplify; one amplified at 100 minutes. In the semi-automated system, DNA was eluted directly into an isothermal reaction solution containing the faster OptiGene DNA polymerase. The low surrogate sputum concentration, 103 TB cells/mL, amplified at 52.8 ± 3.3 minutes, 104 cells/mL at 45.4 ± 11.3 minutes, and 105 cells/mL at 31.8 ± 2.9 minutes. TB negative samples amplified at 66.4 ± 7.4 minutes. This study demonstrated the feasibility of a single tube design for integrating sample preparation and isothermal amplification, which with further development could be useful for point-of-care applications, particularly in a low-resource setting.

  6. The research of combining high resolution melting with multiplex ligation-dependent probe amplification technology in the mutation scanning for PAH gene%联合应用高分辨率熔解曲线和多重连接依赖探针扩增技术对PAH基因突变筛查研究

    Institute of Scientific and Technical Information of China (English)

    季春燕; 孙莉莉; 曹丽华; 胡煜; 黄宏; 王述森; 罗阳


    目的 联合应用高分辨率熔解曲线(high resolution melting,HRM)和多重连接依赖探针扩增(multiplex ligation-dependent probe amplification,MLPA)技术检测苯丙酮尿症(phenylketonuria,PKU)患者基因突变,并探讨两种技术联合运用对于突变筛查的价值.方法 采用HRM和MLPA技术对26例临床诊断为PKU的患者苯丙氨酸羟化酶基因(phenylalanine hydroxylase,PAH)进行检测,并通过测序验证;针对未报道的基因改变进行聚合酶链反应-限制性片段长度多态性分析.结果 在52个等位基因中检测到44个突变等位基因(共21种不同突变),包括第4外显子拷贝数的增加,总检出率达84.62%(44/52),其中c.584_585insA和IVS10+ 1G>T突变在国内外未见报道.此外,R243Q(25%)突变为中国最常见的突变种类.结论 应用HRM和MLPA技术相对提高了PAH基因突变筛查的检出率,检测结果丰富了基因突变数据库,并为临床诊断与产前诊断提供实验室依据.%Objective To explore the value of combining high resolution melting (HRM) with multiplex ligation-dependent probe amplification ( MLPA ) for detecting mutations underlying phenylketonuria.Methods HRM was used for detecting small mutations in phenylalanine hydroxylase gene (PAH) of 26 phenylketonuria patients.The results were verified with DNA sequencing.MLPA was used for detecting potential deletions/duplications in the PAH gene. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was performed for additional potential mutations.Results A total of 21 mutations were found in 44/52 alleles (84.62%),which included a dupEx4.Among the 21 types of mutation,19 were reported previously,and the remaining two were novel mutations:c.584_585insA and IVS10+1G>T.In addition,the mutation of R243Q (25%) was the most common type in China.Conclusion The study showed that the combination of HRM and MLPA could increase the detection rate for mutation in PKU.The study

  7. Experimental observation of sub-terahertz backward-wave amplification in a multi-level microfabricated slow-wave circuit

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Chan-Wook, E-mail:; Ahn, Ho Young; Kim, Yongsung; Lee, Jooho; Hong, Seogwoo; Lee, Sang Hun; Choi, Jun Hee; Kim, Sunil; Kim, Jong Min; Hwang, Sungwoo [Samsung Advanced Institute of Technology, Suwon 443-803 (Korea, Republic of); Jeon, So-Yeon; Yu, SeGi [Department of Physics, Hankuk University of Foreign Studies, Yongin 449-791 (Korea, Republic of); Collins, George; Read, Michael E.; Lawrence Ives, R. [Calabazas Creek Research, Inc., San Mateo, California 94404-1010 (United States)


    In our earlier paper dealing with dispersion retrieval from ultra-deep, reactive-ion-etched, slow-wave circuits on silicon substrates, it was proposed that splitting high-aspect-ratio circuits into multilevels enabled precise characterization in sub-terahertz frequency regime. This achievement prompted us to investigate beam-wave interaction through a vacuum-sealed integration with a 15-kV, 85-mA, thermionic, electron gun. Our experimental study demonstrates sub-terahertz, backward-wave amplification driven by an external oscillator. The measured output shows a frequency downshift, as well as power amplification, from beam loading even with low beam perveance. This offers a promising opportunity for the development of terahertz radiation sources, based on silicon technologies.

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

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


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

  9. A biomimetic multilayer nanofiber fabric fabricated by electrospinning and textile technology from polylactic acid and Tussah silk fibroin as a scaffold for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Weili [Key Laboratory of Advanced Textile Composites, Ministry of Education, Institute of Textile Composites, Tianjin Polytechnic University, Tianjin 300387 (China); Henan provincial key laboratory of functional textile materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, Zhengzhou 450007 (China); He, Jianxin, E-mail: [Henan provincial key laboratory of functional textile materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, Zhengzhou 450007 (China); Han, Qiming [Henan provincial key laboratory of functional textile materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, Zhengzhou 450007 (China); Sang, Feng [Department of Acquired Immune Deficiency Syndrome Treatment and Research Center, The First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou 450000 (China); Wang, Qian [Henan provincial key laboratory of functional textile materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, Zhengzhou 450007 (China); Chen, Li [Key Laboratory of Advanced Textile Composites, Ministry of Education, Institute of Textile Composites, Tianjin Polytechnic University, Tianjin 300387 (China); Cui, Shizhong [Key Laboratory of Advanced Textile Composites, Ministry of Education, Institute of Textile Composites, Tianjin Polytechnic University, Tianjin 300387 (China); Henan provincial key laboratory of functional textile materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Collaborative Innovation Center of Textile and Garment Industry, Henan Province, Zhengzhou 450007 (China); and others


    To engineer bone tissue, a scaffold with good biological properties should be provided to approximate the hierarchical structure of collagen fibrils in natural bone. In this study, we fabricated a novel scaffold consisting of multilayer nanofiber fabrics (MLNFFs) by weaving nanofiber yarns of polylactic acid (PLA) and Tussah silk fibroin (TSF). The yarns were fabricated by electrospinning, and we found that spinnability, as well as the mechanical properties of the resulting scaffold, was determined by the ratio between polylactic acid and Tussah silk fibroin. In particular, a 9:1 mixture can be spun continuously into nanofiber yarns with narrow diameter distribution and good mechanical properties. Accordingly, woven scaffolds based on this mixture had excellent mechanical properties, with Young's modulus 417.65 MPa and tensile strength 180.36 MPa. For nonwoven scaffolds fabricated from the same materials, the Young's modulus and tensile strength were 2- and 4-fold lower, respectively. Woven scaffolds also supported adhesion and proliferation of mouse mesenchymal stem cells, and promoted biomineralization via alkaline phosphatase and mineral deposition. Finally, the scaffolds significantly enhanced the formation of new bone in damaged femoral condyle in rabbits. Thus, the scaffolds are potentially suitable for bone tissue engineering because of biomimetic architecture, excellent mechanical properties, and good biocompatibility. - Highlights: • A novel strategy to mimic the hierarchical collagen fibril in bone is proposed by electrospinning and conventional textile technology. • The tensile strength of the woven scaffold was nearly 4-fold larger than that of nonwoven mats. • The nanofiber woven scaffolds show excellent cytocompatibility and accelerate osteoblast differentiation. • The composite scaffold significantly enhanced formation of new bone in damaged condyles in rabbit femur.

  10. Micro-hybrid electric vehicle application of valve-regulated lead-acid batteries in absorbent glass mat technology: Testing a partial-state-of-charge operation strategy (United States)

    Schaeck, S.; Stoermer, A. O.; Hockgeiger, E.

    The BMW Group has launched two micro-hybrid functions in high volume models in order to contribute to reduction of fuel consumption in modern passenger cars. Both the brake energy regeneration (BER) and the auto-start-stop function (ASSF) are based on the conventional 14 V vehicle electrical system and current series components with only little modifications. An intelligent control algorithm of the alternator enables recuperative charging in braking and coasting phases, known as BER. By switching off the internal combustion engine at a vehicle standstill the idling fuel consumption is effectively reduced by ASSF. By reason of economy and package a lead-acid battery is used as electrochemical energy storage device. The BMW Group assembles valve-regulated lead-acid (VRLA) batteries in absorbent glass mat (AGM) technology in the micro-hybrid electrical power system since special challenges arise for the batteries. By field data analysis a lower average state-of-charge (SOC) due to partial state-of-charge (PSOC) operation and a higher cycling rate due to BER and ASSF are confirmed in this article. Similar to a design of experiment (DOE) like method we present a long-term lab investigation. Two types of 90 Ah VRLA AGM batteries are operated with a test bench profile that simulates the micro-hybrid vehicle electrical system under varying conditions. The main attention of this lab testing is focused on capacity loss and charge acceptance over cycle life. These effects are put into context with periodically refresh charging the batteries in order to prevent accelerated battery aging due to hard sulfation. We demonstrate the positive effect of refresh chargings concerning preservation of battery charge acceptance. Furthermore, we observe moderate capacity loss over 90 full cycles both at 25 °C and at 3 °C battery temperature.

  11. Highly efficient amplification of chronic wasting disease agent by protein misfolding cyclic amplification with beads (PMCAb.

    Directory of Open Access Journals (Sweden)

    Chad J Johnson

    Full Text Available Protein misfolding cyclic amplification (PMCA has emerged as an important technique for detecting low levels of pathogenic prion protein in biological samples. The method exploits the ability of the pathogenic prion protein to convert the normal prion protein to a proteinase K-resistant conformation. Inclusion of Teflon® beads in the PMCA reaction (PMCAb has been previously shown to increase the sensitivity and robustness of detection for the 263 K and SSLOW strains of hamster-adapted prions. Here, we demonstrate that PMCAb with saponin dramatically increases the sensitivity of detection for chronic wasting disease (CWD agent without compromising the specificity of the assay (i.e., no false positive results. Addition of Teflon® beads increased the robustness of the PMCA reaction, resulting in a decrease in the variability of PMCA results. Three rounds of serial PMCAb allowed detection of CWD agent from a 6.7 × 10(-13 dilution of 10% brain homogenate (1.3 fg of source brain. Titration of the same brain homogenate in transgenic mice expressing cervid prion protein (Tg(CerPrP1536(+/- mice allowed detection of CWD agent from the 10(-6 dilution of 10% brain homogenate. PMCAb is, thus, more sensitive than bioassay in transgenic mice by a factor exceeding 10(5. Additionally, we are able to amplify CWD agent from brain tissue and lymph nodes of CWD-positive white-tailed deer having Prnp alleles associated with reduced disease susceptibility.

  12. Highly efficient amplification of chronic wasting disease agent by protein misfolding cyclical amplification with beads (PMCAb) (United States)

    Johnson, Chad J.; Aiken, Judd M.; McKenzie, Debbie; Samuel, Michael D.; Pedersen, Joel A.


    Protein misfolding cyclic amplification (PMCA) has emerged as an important technique for detecting low levels of pathogenic prion protein in biological samples. The method exploits the ability of the pathogenic prion protein to convert the normal prion protein to a proteinase K-resistant conformation. Inclusion of Teflon® beads in the PMCA reaction (PMCAb) has been previously shown to increase the sensitivity and robustness of detection for the 263 K and SSLOW strains of hamster-adapted prions. Here, we demonstrate that PMCAb with saponin dramatically increases the sensitivity of detection for chronic wasting disease (CWD) agent without compromising the specificity of the assay (i.e., no false positive results). Addition of Teflon® beads increased the robustness of the PMCA reaction, resulting in a decrease in the variability of PMCA results. Three rounds of serial PMCAb allowed detection of CWD agent from a 6.7×10−13 dilution of 10% brain homogenate (1.3 fg of source brain). Titration of the same brain homogenate in transgenic mice expressing cervid prion protein (Tg(CerPrP)1536+/−mice) allowed detection of CWD agent from the 10−6 dilution of 10% brain homogenate. PMCAb is, thus, more sensitive than bioassay in transgenic mice by a factor exceeding 105. Additionally, we are able to amplify CWD agent from brain tissue and lymph nodes of CWD-positive white-tailed deer having Prnp alleles associated with reduced disease susceptibility.

  13. Rapid DNA amplification using a battery-powered thin-film resistive thermocycler. (United States)

    Herold, Keith E; Sergeev, Nikolay; Matviyenko, Andriy; Rasooly, Avraham


    A prototype handheld, compact, rapid thermocycler was developed for multiplex analysis of nucleic acids in an inexpensive, portable configuration. Instead of the commonly used Peltier heating/cooling element, electric thin-film resistive heater and a miniature fan enable rapid heating and cooling of glass capillaries leading to a simple, low-cost Thin-Film Resistive Thermocycler (TFRT). Computer-based pulse width modulation control yields heating rates of 6-7 K/s and cooling rates of 5 K/s. The four capillaries are closely coupled to the heater, resulting in low power consumption. The energy required by a nominal PCR cycle (20 s at each temperature) was found to be 57+/-2 J yielding an average power of approximately 1.0 W (not including the computer and the control system). Thus the device can be powered by a standard 9 V alkaline battery (or other 9 V power supply). The prototype TFRT was demonstrated (in a benchtop configuration) for detection of three important food pathogens (E. coli ETEC, Shigella dysenteriae, and Salmonella enterica). PCR amplicons were analyzed by gel electrophoresis. The 35 cycle PCR protocol using a single channel was completed in less then 18 min. Simple and efficient heating/cooling, low cost, rapid amplification, and low power consumption make the device suitable for portable DNA amplification applications including clinical point of care diagnostics and field use.

  14. Distinguishing mechanisms of plasma-based amplification for short laser pulses (United States)

    Jia, Qing; Edwards, Matthew; Barth, Ido; Mikhailova, Julia; Fisch, Nathaniel


    Several plasma-based amplification mechanisms have been proposed to obtain short laser pulses with ultrahigh intensities beyond the damage threshold of solid-state devices, including Compton-like superradiant amplification, backward Raman amplification and strongly-coupled Brillouin amplification. These three mechanisms are all based on the periodic structure of particle (electrons for the former two and ions for Brillouin amplification) density fluctuations that function as a grating. By turning off the ion motion in particle-in-cell simulations, we can distinguish Brillouin from Raman, and show that Raman amplification is responsible for the main leading spike amplification of ultrashort pulses. By artificially turning off the longitudinal electric field (Ex) in simulations, we can distinguish Raman from Compton-like superradiant amplification. Interestingly, we find that the superradiant amplification in Ex-off simulation is similar to the amplification in pair plasmas, with roughly half amplification efficiency of the latter due to absence of equal contribution from positrons. In addition, we also discuss the competition between Brillouin amplification and superradiant amplification in pair plasmas by comparing the dominance of thermal pressure and ponderomotive force.

  15. Study on the Technology of Detoxification of Rapeseed Meal by Acid Solvent%酸溶液对菜籽粕脱毒工艺探讨