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  1. Cyclophilin B enhances HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    DeBoer, Jason; Madson, Christian J. [Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE (United States); Belshan, Michael, E-mail: michaelbelshan@creighton.edu [Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE (United States); The Nebraska Center for Virology, University of Nebraska, Lincoln, NE (United States)

    2016-02-15

    Cyclophilin B (CypB) is a member of the immunophilin family and intracellular chaperone. It predominantly localizes to the ER, but also contains a nuclear localization signal and is secreted from cells. CypB has been shown to interact with the Gag protein of human immunodeficiency type 1 (HIV-1). Several proteomic and genetic studies identified it as a potential factor involved in HIV replication. Herein, we show that over-expression of CypB enhances HIV infection by increasing nuclear import of viral DNA. This enhancement was unaffected by cyclosporine treatment and requires the N-terminus of the protein. The N-terminus contains an ER leader sequence, putative nuclear localization signal, and is required for secretion. Deletion of the N-terminus resulted in mislocalization from the ER and suppression of HIV infection. Passive transfer experiments showed that secreted CypB did not impact HIV infection. Combined, these experiments show that intracellular CypB modulates a pathway of HIV nuclear import. - Highlights: • CypB has been identified in several proteomic studies of HIV-1 infection. • CypB expression is upregulated in activated and infected T-cells. • Over-expression of CypB enhances HIV nuclear import and infection. • The N-terminus of CypB is necessary for these effects.

  2. Blocking type I interferon signaling enhances T cell recovery and reduces HIV-1 reservoirs

    Science.gov (United States)

    Cheng, Liang; Ma, Jianping; Li, Jingyun; Li, Dan; Li, Guangming; Li, Feng; Zhang, Qing; Yu, Haisheng; Yasui, Fumihiko; Ye, Chaobaihui; Tsao, Li-Chung; Zhang, Liguo

    2016-01-01

    Despite the efficient suppression of HIV-1 replication that can be achieved with combined antiretroviral therapy (cART), low levels of type I interferon (IFN-I) signaling persist in some individuals. This sustained signaling may impede immune recovery and foster viral persistence. Here we report studies using a monoclonal antibody to block IFN-α/β receptor (IFNAR) signaling in humanized mice (hu-mice) that were persistently infected with HIV-1. We discovered that effective cART restored the number of human immune cells in HIV-1–infected hu-mice but did not rescue their immune hyperactivation and dysfunction. IFNAR blockade fully reversed HIV-1–induced immune hyperactivation and rescued anti–HIV-1 immune responses in T cells from HIV-1–infected hu-mice. Finally, we found that IFNAR blockade in the presence of cART reduced the size of HIV-1 reservoirs in lymphoid tissues and delayed HIV-1 rebound after cART cessation in the HIV-1–infected hu-mice. We conclude that low levels of IFN-I signaling contribute to HIV-1–associated immune dysfunction and foster HIV-1 persistence in cART-treated hosts. Our results suggest that blocking IFNAR may provide a potential strategy to enhance immune recovery and reduce HIV-1 reservoirs in individuals with sustained elevations in IFN-I signaling during suppressive cART. PMID:27941247

  3. Interactions Between HIV-1 Gag and Viral RNA Genome Enhance Virion Assembly

    DEFF Research Database (Denmark)

    Dilley, Kari A; Nikolaitchik, Olga A; Galli, Andrea

    2017-01-01

    in this process. The mechanism that allows HIV-1 to achieve such high efficiency of genome packaging when a packageable viral RNA is not required for virus assembly is currently unknown. In this report, we examined the role of HIV-1 RNA in virus assembly and found that packageable HIV-1 RNA enhances particle......Most HIV-1 virions contain two copies of full-length viral RNA, indicating that genome packaging is efficient and tightly regulated. However, the structural protein Gag is the only component required for the assembly of noninfectious virus-like particles and the viral RNA is dispensable...... into each nascent virion. These studies shed light on the mechanism by which HIV-1 achieves efficient genome packaging during virus assembly.IMPORTANCE Retrovirus assembly is a well-choreographed event, during which many viral and cellular components come together to generate infectious virions. The viral...

  4. Interactions Between HIV-1 Gag and Viral RNA Genome Enhance Virion Assembly

    DEFF Research Database (Denmark)

    Dilley, Kari A; Nikolaitchik, Olga A; Galli, Andrea

    2017-01-01

    Most HIV-1 virions contain two copies of full-length viral RNA, indicating that genome packaging is efficient and tightly regulated. However, the structural protein Gag is the only component required for the assembly of noninfectious virus-like particles and the viral RNA is dispensable...... in this process. The mechanism that allows HIV-1 to achieve such high efficiency of genome packaging when a packageable viral RNA is not required for virus assembly is currently unknown. In this report, we examined the role of HIV-1 RNA in virus assembly and found that packageable HIV-1 RNA enhances particle...... into each nascent virion. These studies shed light on the mechanism by which HIV-1 achieves efficient genome packaging during virus assembly.IMPORTANCE Retrovirus assembly is a well-choreographed event, during which many viral and cellular components come together to generate infectious virions. The viral...

  5. Electroluminescence Efficiency Enhancement using Metal Nanoparticles

    National Research Council Canada - National Science Library

    Soref, Richard A; Khurgin, J. B; Sun, G

    2008-01-01

    We apply the "effective mode volume" theory to evaluate enhancement of the electroluminescence efficiency of semiconductor emitters placed in the vicinity of isolated metal nanoparticles and their arrays...

  6. HIV Coinfection Enhances Complement Activation During Sepsis

    NARCIS (Netherlands)

    Huson, Michaëla A. M.; Wouters, Diana; van Mierlo, Gerard; Grobusch, Martin P.; Zeerleder, Sacha S.; van der Poll, Tom

    2015-01-01

    Human immunodeficiency virus (HIV)-induced complement activation may play a role in chronic immune activation in patients with HIV infection and influence the complement system during acute illness. We determined the impact of HIV infection on the complement system in patients with asymptomatic HIV

  7. [Enhanced prenatal HIV couple oriented counselling session and couple communication about HIV (ANRS 12127 Prenahtest Trial)].

    Science.gov (United States)

    Plazy, M; Orne-Gliemann, J; Balestre, E; Miric, M; Darak, S; Butsashvili, M; Tchendjou, P; Dabis, F; Desgrées du Loû, A

    2013-08-01

    The Prenahtest study investigated the efficacy of a couple-oriented HIV counselling session (COC) in encouraging couple HIV counselling and testing, and improving intra-couple communication about sexual and reproductive health. We report here on the effect of COC on intra-couple communication about HIV. Within this 4-country trial (India, Georgia, Dominican Republic and Cameroon), 484 to 491 pregnant women per site were recruited and individually randomized to receive either the COC intervention, enhanced counselling with role playing, or standard post-test HIV counselling. Women were interviewed at recruitment, before HIV testing (T0), and 2 to 8 weeks after post-test HIV counselling (T1). Four dichotomous variables documented intra-couple communication about HIV at T1: 1) discussion about HIV, 2) discussion about condom use, 3) suggesting HIV testing and 4) suggesting couple HIV counselling to the partner. An intra-couple HIV communication index was created: low degree of communication ("yes" response to zero or one of the four variables), intermediate degree of communication ("yes" to two or three variables) or high degree of communication ("yes" to the four variables). To estimate the impact of COC on the intra-couple HIV communication index, multivariable logistic regressions were conducted. One thousand six hundred and seven women were included in the analysis of whom 54 (3.4%) were HIV-infected (49 in Cameroon). In the four countries, the counselling group was associated with intra-couple HIV communication (P≤0.03): women allocated to the COC group were significantly more likely to report high or intermediate degrees of intra-couple communication about HIV (versus low degree of communication) than women allocated to standard counselling. COC improved short-term communication about HIV within couples in different sociocultural contexts, a positive finding for a couple approach to HIV prevention. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  8. Aerodynamic Efficiency Enhancements for Air Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The need for aerodynamics-based efficiency enhancements for air vehicles is presented. The results of the Phase I investigation of concepts for morphing aircraft are...

  9. Aerodynamic Efficiency Enhancements for Air Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The need for aerodynamics-based efficiency enhancements for air vehicles is presented. Concepts are presented for morphing aircraft, to enable the aircraft to...

  10. evolution of hiv training for enhanced care provision in kenya

    African Journals Online (AJOL)

    12 (Supplement) December 2013. EVOLUTION OF HIV TRAINING FOR ENHANCED CARE PROVISION IN KENYA: CHALLENGES AND ... Objective: To provide an overview of the evolution of HIV training in Kenya, from. 2003 to date ..... for training, lack of necessary equipment, inadequate remuneration and benefit and.

  11. Interactions Between HIV-1 Gag and Viral RNA Genome Enhance Virion Assembly

    DEFF Research Database (Denmark)

    Dilley, Kari A; Nikolaitchik, Olga A; Galli, Andrea

    2017-01-01

    in this process. The mechanism that allows HIV-1 to achieve such high efficiency of genome packaging when a packageable viral RNA is not required for virus assembly is currently unknown. In this report, we examined the role of HIV-1 RNA in virus assembly and found that packageable HIV-1 RNA enhances particle...... production when Gag is expressed at levels similar to those in cells containing one provirus. However, such enhancement is diminished when Gag is overexpressed, suggesting that the effects of viral RNA can be replaced by increased Gag concentration in cells. We also showed that the specific interactions...... between Gag and viral RNA are required for the enhancement of particle production. Taken together, these studies are consistent with our previous hypothesis that specific dimeric viral RNA:Gag interactions are the nucleation event of infectious virion assembly, ensuring that one RNA dimer is packaged...

  12. Heroin Inhibits HIV-Restriction miRNAs and Enhances HIV Infection of Macrophages

    Directory of Open Access Journals (Sweden)

    Xu eWang

    2015-11-01

    Full Text Available Although opioids have been extensively studied for their impact on the immune system, limited information is available about the specific actions of opioids on intracellular antiviral innate immunity against HIV infection. Thus, we investigated whether heroin, one of the most abused drugs, inhibits the expression of intracellular HIV restriction microRNA (miRNA and facilitates HIV replication in macrophages. Heroin treatment of macrophages enhanced HIV replication, which was associated with the downregulation of several HIV restriction miRNAs. These heroin-mediated actions on the miRNAs and HIV could be antagonized by naltrexone, an opioid receptor antagonist. Furthermore, the in vitro negative impact of heroin on HIV-associated miRNAs was confirmed by the in vivo observation that heroin addicts had significantly lower levels of macrophage-derived HIV restriction miRNAs than those in the control subjects. These in vitro and in vivo findings indicate that heroin use compromises intracellular anti-HIV innate immunity, providing a favorable microenvironment for HIV survival in the target cells.

  13. Delocalized Quantum States Enhance Photocell Efficiency

    CERN Document Server

    Zhang, Yiteng; Alharbi, Fahhad H; Engel, Greg; Kais, Sabre

    2014-01-01

    The high quantum efficiency of photosynthetic complexes has inspired researchers to explore new routes to utilize this process for photovoltaic devices. Quantum coherence has been demonstrated to play a crucial role within this process. Herein, we propose a three-dipole system as a model of a new photocell type which exploits the coherence among its three dipoles. We have proved that the efficiency of such a photocell is greatly enhanced by quantum coherence. We have also predicted that the photocurrents can be enhanced by about 49.5 % in such a coherent coupled dipole system compared with the uncoupled dipoles. These results suggest a promising novel design aspect of photosynthesis-mimicking photovoltaic devices.

  14. Factors of intermittent HIV-1 excretion in semen and efficiency of sperm processing in obtaining spermatozoa without HIV-1 genomes.

    Science.gov (United States)

    Bujan, Louis; Daudin, Myriam; Matsuda, Tomohiro; Righi, Laurence; Thauvin, Laurence; Berges, Laetitia; Izopet, Jacques; Berrebi, Alain; Massip, Patrice; Pasquier, Christophe

    2004-03-26

    To study the risk factors for HIV-1 in semen according to the localization of HIV-1 in sperm cell fractions and to assess the efficiency of sperm processing in obtaining spermatozoa without HIV-1 genomes. Ninety-four HIV-infected patients provided 281 paired blood and semen samples. Sperm cell separation was performed using two successive methods. HIV-1 RNA was quantified in blood and seminal plasma. HIV-1 RNA and DNA were detected in cell fractions. HIV-1 RNA was found in 14% of seminal plasma samples and up to 8.7% of native semen cells were positive for HIV-1 RNA and DNA. Ten seminal plasma samples had detectable RNA although blood viral load was undetectable. Antiretroviral treatment reduced the likelihood of RNA detection in seminal plasma. For semen with polynuclear cells and HIV-1 RNA in seminal plasma, the likelihood of detecting HIV-1 genomes in semen cells was increased fourfold and sixfold, respectively. In 25% of patients, HIV-1 excretion was intermittent. In the group of patients with systematic negative seminal plasma, HIV-1 genomes were detected in up to 10% of sperm cell samples. Our method of sperm processing always enabled us to obtain spermatozoa without detectable HIV-1 genomes. Polynuclear cells in semen are a risk factor for seminal HIV-1 excretion. Blood viral load was the only predictive factor for the intermittence of HIV-1 excretion in semen over time. Sperm processing using two successive methods was effective in obtaining spermatozoa without detectable HIV-1 genomes regardless of the viral load level in native semen.

  15. Enhancement of Probe Signal for Screening of HIV-1 Protease Inhibitors in Living Cells

    Directory of Open Access Journals (Sweden)

    Huantong Yao

    2012-12-01

    Full Text Available The global human immunodeficiency virus infection/acquired immuno-deficiency syndrome (HIV/AIDS epidemic is one of the biggest threats to human life. Mutation of the virus and toxicity of the existing drugs necessitate the development of new drugs for effective AIDS treatment. Previously, we developed a molecular probe that utilizes the Förster resonance energy transfer (FRET principle to visualize HIV-1 protease inhibition within living cells for drug screening. We explored using AcGFP1 (a fluorescent mutant of the wild-type green fluorescent protein as a donor and mCherry (a mutant of red fluorescent protein as an acceptor for FRET microscopy imaging measurement of HIV-1 protease activity within living cells and demonstrated that the molecular probe is suitable for the High-Content Screening (HCS of anti-HIV drugs through an automated FRET microscopy imaging measurement. In this study, we genetically engineered a probe with a tandem acceptor protein structure to enhance the probe’s signal. Both in vitro and in vivo studies revealed that the novel structure of the molecular probe exhibits a significant enhancement of FRET signals, reaching a probe FRET efficiency of 34%, as measured by fluorescence lifetime imaging microscopy (FLIM measurement. The probe developed herein would enable high-content screening of new anti-HIV agents.

  16. A novel trifunctional IgG-like bispecific antibody to inhibit HIV-1 infection and enhance lysis of HIV by targeting activation of complement

    Directory of Open Access Journals (Sweden)

    Tomlinson Stephen

    2010-06-01

    Full Text Available Abstract Background The complement system is not only a key component of innate immunity but also provides a first line of defense against invading pathogens, especially for viral pathogens. Human immunodeficiency virus (HIV, however, possesses several mechanisms to evade complement-mediated lysis (CoML and exploit the complement system to enhance viral infectivity. Responsible for this intrinsic resistance against complement-mediated virolysis are complement regulatory membrane proteins derived from the host cell that inherently downregulates complement activation at several stages of the cascade. In addition, HIV is protected from complement-mediated lysis by binding soluble factor H (fH through the viral envelope proteins, gp120 and gp41. Whereas inhibition of complement activity is the desired outcome in the vast majority of therapeutic approaches, there is a broader potential for complement-mediated inhibition of HIV by complement local stimulation. Presentation of the hypothesis Our previous studies have proven that the complement-mediated antibody-dependent enhancement of HIV infection is mediated by the association of complement receptor type 2 bound to the C3 fragment and deposited on the surface of HIV virions. Thus, we hypothesize that another new activator of complement, consisting of two dsFv (against gp120 and against C3d respectively linked to a complement-activating human IgG1 Fc domain ((anti-gp120 × anti-C3d-Fc, can not only target and amplify complement activation on HIV virions for enhancing the efficiency of HIV lysis, but also reduce the infectivity of HIV through blocking the gp120 and C3d on the surface of HIV. Testing the hypothesis Our hypothesis was tested using cell-free HIV-1 virions cultivated in vitro and assessment of virus opsonization was performed by incubating appropriate dilutions of virus with medium containing normal human serum and purified (anti-gp120 × anti-C3d-Fc proteins. As a control group, viruses

  17. Interactions between HIV-1 Gag and Viral RNA Genome Enhance Virion Assembly.

    Science.gov (United States)

    Dilley, Kari A; Nikolaitchik, Olga A; Galli, Andrea; Burdick, Ryan C; Levine, Louis; Li, Kelvin; Rein, Alan; Pathak, Vinay K; Hu, Wei-Shau

    2017-08-15

    Most HIV-1 virions contain two copies of full-length viral RNA, indicating that genome packaging is efficient and tightly regulated. However, the structural protein Gag is the only component required for the assembly of noninfectious viruslike particles, and the viral RNA is dispensable in this process. The mechanism that allows HIV-1 to achieve such high efficiency of genome packaging when a packageable viral RNA is not required for virus assembly is currently unknown. In this report, we examined the role of HIV-1 RNA in virus assembly and found that packageable HIV-1 RNA enhances particle production when Gag is expressed at levels similar to those in cells containing one provirus. However, such enhancement is diminished when Gag is overexpressed, suggesting that the effects of viral RNA can be replaced by increased Gag concentration in cells. We also showed that the specific interactions between Gag and viral RNA are required for the enhancement of particle production. Taken together, these studies are consistent with our previous hypothesis that specific dimeric viral RNA-Gag interactions are the nucleation event of infectious virion assembly, ensuring that one RNA dimer is packaged into each nascent virion. These studies shed light on the mechanism by which HIV-1 achieves efficient genome packaging during virus assembly.IMPORTANCE Retrovirus assembly is a well-choreographed event, during which many viral and cellular components come together to generate infectious virions. The viral RNA genome carries the genetic information to new host cells, providing instructions to generate new virions, and therefore is essential for virion infectivity. In this report, we show that the specific interaction of the viral RNA genome with the structural protein Gag facilitates virion assembly and particle production. These findings resolve the conundrum that HIV-1 RNA is selectively packaged into virions with high efficiency despite being dispensable for virion assembly

  18. Arctigenin efficiently enhanced sedentary mice treadmill endurance.

    Science.gov (United States)

    Tang, Xuan; Zhuang, Jingjing; Chen, Jing; Yu, Liang; Hu, Lihong; Jiang, Hualiang; Shen, Xu

    2011-01-01

    Physical inactivity is considered as one of the potential risk factors for the development of type 2 diabetes and other metabolic diseases, while endurance exercise training could enhance fat oxidation that is associated with insulin sensitivity improvement in obesity. AMP-activated protein kinase (AMPK) as an energy sensor plays pivotal roles in the regulation of energy homeostasis, and its activation could improve glucose uptake, promote mitochondrial biogenesis and increase glycolysis. Recent research has even suggested that AMPK activation contributed to endurance enhancement without exercise. Here we report that the natural product arctigenin from the traditional herb Arctium lappa L. (Compositae) strongly increased AMPK phosphorylation and subsequently up-regulated its downstream pathway in both H9C2 and C2C12 cells. It was discovered that arctigenin phosphorylated AMPK via calmodulin-dependent protein kinase kinase (CaMKK) and serine/threonine kinase 11(LKB1)-dependent pathways. Mice treadmill based in vivo assay further indicated that administration of arctigenin improved efficiently mice endurance as reflected by the increased fatigue time and distance, and potently enhanced mitochondrial biogenesis and fatty acid oxidation (FAO) related genes expression in muscle tissues. Our results thus suggested that arctigenin might be used as a potential lead compound for the discovery of the agents with mimic exercise training effects to treat metabolic diseases.

  19. Arctigenin efficiently enhanced sedentary mice treadmill endurance.

    Directory of Open Access Journals (Sweden)

    Xuan Tang

    Full Text Available Physical inactivity is considered as one of the potential risk factors for the development of type 2 diabetes and other metabolic diseases, while endurance exercise training could enhance fat oxidation that is associated with insulin sensitivity improvement in obesity. AMP-activated protein kinase (AMPK as an energy sensor plays pivotal roles in the regulation of energy homeostasis, and its activation could improve glucose uptake, promote mitochondrial biogenesis and increase glycolysis. Recent research has even suggested that AMPK activation contributed to endurance enhancement without exercise. Here we report that the natural product arctigenin from the traditional herb Arctium lappa L. (Compositae strongly increased AMPK phosphorylation and subsequently up-regulated its downstream pathway in both H9C2 and C2C12 cells. It was discovered that arctigenin phosphorylated AMPK via calmodulin-dependent protein kinase kinase (CaMKK and serine/threonine kinase 11(LKB1-dependent pathways. Mice treadmill based in vivo assay further indicated that administration of arctigenin improved efficiently mice endurance as reflected by the increased fatigue time and distance, and potently enhanced mitochondrial biogenesis and fatty acid oxidation (FAO related genes expression in muscle tissues. Our results thus suggested that arctigenin might be used as a potential lead compound for the discovery of the agents with mimic exercise training effects to treat metabolic diseases.

  20. Arctigenin Efficiently Enhanced Sedentary Mice Treadmill Endurance

    Science.gov (United States)

    Chen, Jing; Yu, Liang; Hu, Lihong; Jiang, Hualiang; Shen, Xu

    2011-01-01

    Physical inactivity is considered as one of the potential risk factors for the development of type 2 diabetes and other metabolic diseases, while endurance exercise training could enhance fat oxidation that is associated with insulin sensitivity improvement in obesity. AMP-activated protein kinase (AMPK) as an energy sensor plays pivotal roles in the regulation of energy homeostasis, and its activation could improve glucose uptake, promote mitochondrial biogenesis and increase glycolysis. Recent research has even suggested that AMPK activation contributed to endurance enhancement without exercise. Here we report that the natural product arctigenin from the traditional herb Arctium lappa L. (Compositae) strongly increased AMPK phosphorylation and subsequently up-regulated its downstream pathway in both H9C2 and C2C12 cells. It was discovered that arctigenin phosphorylated AMPK via calmodulin-dependent protein kinase kinase (CaMKK) and serine/threonine kinase 11(LKB1)-dependent pathways. Mice treadmill based in vivo assay further indicated that administration of arctigenin improved efficiently mice endurance as reflected by the increased fatigue time and distance, and potently enhanced mitochondrial biogenesis and fatty acid oxidation (FAO) related genes expression in muscle tissues. Our results thus suggested that arctigenin might be used as a potential lead compound for the discovery of the agents with mimic exercise training effects to treat metabolic diseases. PMID:21887385

  1. COFFEE - Coherent Optical System Field Trial for Spectral Efficiency Enhancement

    DEFF Research Database (Denmark)

    Imran, Muhammad; Fresi, Francesco; Rommel, Simon

    2016-01-01

    The scope, aims, and contributions of the COFFEE project for spectral efficiency enhancement and market exposure are presented.......The scope, aims, and contributions of the COFFEE project for spectral efficiency enhancement and market exposure are presented....

  2. Efficient and robust gradient enhanced Kriging emulators.

    Energy Technology Data Exchange (ETDEWEB)

    Dalbey, Keith R.

    2013-08-01

    %E2%80%9CNaive%E2%80%9D or straight-forward Kriging implementations can often perform poorly in practice. The relevant features of the robustly accurate and efficient Kriging and Gradient Enhanced Kriging (GEK) implementations in the DAKOTA software package are detailed herein. The principal contribution is a novel, effective, and efficient approach to handle ill-conditioning of GEK's %E2%80%9Ccorrelation%E2%80%9D matrix, RN%CC%83, based on a pivoted Cholesky factorization of Kriging's (not GEK's) correlation matrix, R, which is a small sub-matrix within GEK's RN%CC%83 matrix. The approach discards sample points/equations that contribute the least %E2%80%9Cnew%E2%80%9D information to RN%CC%83. Since these points contain the least new information, they are the ones which when discarded are both the easiest to predict and provide maximum improvement of RN%CC%83's conditioning. Prior to this work, handling ill-conditioned correlation matrices was a major, perhaps the principal, unsolved challenge necessary for robust and efficient GEK emulators. Numerical results demonstrate that GEK predictions can be significantly more accurate when GEK is allowed to discard points by the presented method. Numerical results also indicate that GEK can be used to break the curse of dimensionality by exploiting inexpensive derivatives (such as those provided by automatic differentiation or adjoint techniques), smoothness in the response being modeled, and adaptive sampling. Development of a suitable adaptive sampling algorithm was beyond the scope of this work; instead adaptive sampling was approximated by omitting the cost of samples discarded by the presented pivoted Cholesky approach.

  3. First Phase I human clinical trial of a killed whole-HIV-1 vaccine: demonstration of its safety and enhancement of anti-HIV antibody responses.

    Science.gov (United States)

    Choi, Eunsil; Michalski, Chad J; Choo, Seung Ho; Kim, Gyoung Nyoun; Banasikowska, Elizabeth; Lee, Sangkyun; Wu, Kunyu; An, Hwa-Yong; Mills, Anthony; Schneider, Stefan; Bredeek, U Fritz; Coulston, Daniel R; Ding, Shilei; Finzi, Andrés; Tian, Meijuan; Klein, Katja; Arts, Eric J; Mann, Jamie F S; Gao, Yong; Kang, C Yong

    2016-11-28

    Vaccination with inactivated (killed) whole-virus particles has been used to prevent a wide range of viral diseases. However, for an HIV vaccine this approach has been largely negated due to inherent safety concerns, despite the ability of killed whole-virus vaccines to generate a strong, predominantly antibody-mediated immune response in vivo. HIV-1 Clade B NL4-3 was genetically modified by deleting the nef and vpu genes and substituting the coding sequence for the Env signal peptide with that of honeybee melittin signal peptide to produce a less virulent and more replication efficient virus. This genetically modified virus (gmHIV-1NL4-3) was inactivated and formulated as a killed whole-HIV vaccine, and then used for a Phase I human clinical trial (Trial Registration: Clinical Trials NCT01546818). The gmHIV-1NL4-3 was propagated in the A3.01 human T cell line followed by virus purification and inactivation with aldrithiol-2 and γ-irradiation. Thirty-three HIV-1 positive volunteers receiving cART were recruited for this observer-blinded, placebo-controlled Phase I human clinical trial to assess the safety and immunogenicity. Genetically modified and killed whole-HIV-1 vaccine, SAV001, was well tolerated with no serious adverse events. HIV-1NL4-3-specific PCR showed neither evidence of vaccine virus replication in the vaccine virus-infected human T lymphocytes in vitro nor in the participating volunteers receiving SAV001 vaccine. Furthermore, SAV001 with adjuvant significantly increased the pre-existing antibody response to HIV-1 proteins. Antibodies in the plasma of vaccinees were also found to recognize HIV-1 envelope protein on the surface of infected cells as well as showing an enhancement of broadly neutralizing antibodies inhibiting tier I and II of HIV-1 B, D, and A subtypes. The killed whole-HIV vaccine, SAV001, is safe and triggers anti-HIV immune responses. It remains to be determined through an appropriate trial whether this immune response prevents HIV

  4. Complement-mediated enhancement of HIV-1 infection in peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Nielsen, S D; Sørensen, A M; Schønning, Kristian

    1997-01-01

    We investigated if complement-mediated enhancement of HIV infection occurs in peripheral blood mononuclear cells (PBMC). In 7 experiments, we evaluated the effect of human complement on HIVIIIB infection in vitro. We measured HIV antigen production on day 4 and found that pre-incubation of HIV wi...

  5. Quantum Dot Spectrum Converters for Enhanced High Efficiency Photovoltaics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This research proposes to enhance solar cell efficiency, radiation resistance and affordability. The Quantum Dot Spectrum Converter (QDSC) disperses quantum dots...

  6. Hiv/aids and farms' production efficiency in benue state, nigeria ...

    African Journals Online (AJOL)

    The paper evaluates the impact of the health status of farm households with respect to HIV/AIDS on their cropping patterns, incomes and technical efficiencies in Benue State of Nigeria. Primary data was collected from 155 farm households made up of 55 HIV/AIDS and related sicknesses infected households and 100 non- ...

  7. HIV-antibody complexes enhance production of type I interferon by plasmacytoid dendritic cells.

    Science.gov (United States)

    Veenhuis, Rebecca T; Freeman, Zachary T; Korleski, Jack; Cohen, Laura K; Massaccesi, Guido; Tomasi, Alessandra; Boesch, Austin W; Ackerman, Margaret E; Margolick, Joseph B; Blankson, Joel N; Chattergoon, Michael A; Cox, Andrea L

    2017-10-30

    Type I IFN production is essential for innate control of acute viral infection; however, prolonged high-level IFN production is associated with chronic immune activation in HIV-infected individuals. Although plasmacytoid DCs (pDCs) are a primary source of IFN, the mechanisms that regulate IFN levels following the acute phase are unknown. We hypothesized that HIV-specific Ab responses regulate late IFN production. We evaluated the mechanism through which HIV-activated pDCs produce IFN as well as how both monoclonal HIV-specific Abs and Abs produced in natural HIV infection modulated normal pDC sensing of HIV. We found that HIV-induced IFN production required TLR7 signaling, receptor-mediated entry, fusion, and viral uncoating, but not endocytosis or HIV life cycle stages after uncoating. Abs directed against the HIV envelope that do not interfere with CD4 binding markedly enhanced the IFN response, irrespective of their ability to neutralize CD4+ T cell infection. Ab-mediated enhancement of IFN production required Fc γ receptor engagement, bypassed fusion, and initiated signaling through both TLR7 and TLR9, which was not utilized in the absence of Ab. Polyclonal Abs isolated from HIV-infected subjects also enhanced pDC production of IFN in response to HIV. Our data provide an explanation for high levels of IFN production and immune activation in chronic HIV infection.

  8. Enhancing psychosocial support for HIV positive adolescents in Harare, Zimbabwe.

    Directory of Open Access Journals (Sweden)

    Webster Mavhu

    Full Text Available There is a recognized gap in the evidence base relating to the nature and components of interventions to address the psycho-social needs of HIV positive young people. We used mixed methods research to strengthen a community support group intervention for HIV positive young people based in Harare, Zimbabwe.A quantitative questionnaire was administered to HIV positive Africaid support group attendees. Afterwards, qualitative data were collected from young people aged 15-18 through tape-recorded in-depth interviews (n=10, 3 focus group discussions (FGDs and 16 life history narratives. Data were also collected from caregivers, health care workers, and community members through FGDs (n=6 groups and in-depth interviews (n=12. Quantitative data were processed and analysed using STATA 10. Qualitative data were analysed using thematic analysis.229/310 young people completed the quantitative questionnaire (74% participation. Median age was 14 (range 6-18 years; 59% were female. Self-reported adherence to antiretrovirals was sub-optimal. Psychological well being was poor (median score on Shona Symptom Questionnaire 9/14; 63% were at risk of depression. Qualitative findings suggested that challenges faced by positive children include verbal abuse, stigma, and discrimination. While data showed that support group attendance is helpful, young people stressed that life outside the confines of the group was more challenging. Caregivers felt ill-equipped to support the children in their care. These data, combined with a previously validated conceptual framework for family-centred interventions, were used to guide the development of the existing programme of adolescent support groups into a more comprehensive evidence-based psychosocial support programme encompassing caregiver and household members.This study allowed us to describe the lived experiences of HIV positive young people and their caregivers in Zimbabwe. The findings contributed to the enhancement of

  9. Enhanced efficiency of internal combustion engines by employing spinning gas.

    Science.gov (United States)

    Geyko, V I; Fisch, N J

    2014-08-01

    The efficiency of the internal combustion engine might be enhanced by employing spinning gas. A gas spinning at near sonic velocities has an effectively higher heat capacity, which allows practical fuel cycles, which are far from the Carnot efficiency, to approach more closely the Carnot efficiency. A remarkable gain in fuel efficiency is shown to be theoretically possible for the Otto and Diesel cycles. The use of a flywheel, in principle, could produce even greater increases in efficiency.

  10. Complement-mediated enhancement of HIV-1 infection in peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Nielsen, S D; Sørensen, A M; Schønning, Kristian

    1997-01-01

    We investigated if complement-mediated enhancement of HIV infection occurs in peripheral blood mononuclear cells (PBMC). In 7 experiments, we evaluated the effect of human complement on HIVIIIB infection in vitro. We measured HIV antigen production on day 4 and found that pre-incubation of HIV...... with complement led to enhanced production of antigen with a median enhancement of 2.5-fold (range 1.1-6.8). This complement-mediated increase in antigen production was statistically significant (p tested in CD4 cells enriched from PBMC, and CD4...... cells persistently gave higher levels of infection enhancement than PBMC. Thus, CD4 cells appear to be sufficient for complement-mediated enhancement of HIV infection to occur. In addition, we tested if it was possible to detect complement-mediated enhancement of primary HIV isolates in PBMC. We tested...

  11. Traveling-Wave Tube Efficiency Enhancement

    Science.gov (United States)

    Dayton, James A., Jr.

    2011-01-01

    Traveling-wave tubes (TWT's) are used to amplify microwave communication signals on virtually all NASA and commercial spacecraft. Because TWT's are a primary power user, increasing their power efficiency is important for reducing spacecraft weight and cost. NASA Glenn Research Center has played a major role in increasing TWT efficiency over the last thirty years. In particular, two types of efficiency optimization algorithms have been developed for coupled-cavity TWT's. The first is the phase-adjusted taper which was used to increase the RF power from 420 to 1000 watts and the RF efficiency from 9.6% to 22.6% for a Ka-band (29.5 GHz) TWT. This was a record efficiency at this frequency level. The second is an optimization algorithm based on simulated annealing. This improved algorithm is more general and can be used to optimize efficiency over a frequency bandwidth and to provide a robust design for very high frequency TWT's in which dimensional tolerance variations are significant.

  12. Nano-materials for enhanced thermoelectric efficiencies

    Science.gov (United States)

    Boukai, Akram

    2010-04-01

    Energy is the ultimate currency that drives the world economy. Without energy, the global economy would cease to function normally. Most of the world's energy comes from the burning of fossil fuels such as coal and oil. Unfortunately, these fossil fuels are limited and pollute the atmosphere. The rising costs and demand of energy products and the alarming rate of global warming have focused research efforts into alternative forms of renewable energy. Thermoelectrics are one class of renewable energy producing devices. Thermoelectrics operate by converting temperature differences into electrical power and vice versa. They find limited use due to their low efficiencies and high cost. This article will review the operation of thermoelectrics and their current state-of-the-art. It will also explore future promising research endeavors that aim to increase their efficiency.

  13. Cognitive radio applications for enhanced spectrum efficiency

    OpenAIRE

    Petrini, Valeria

    2013-01-01

    The aim of this thesis is the study of techniques for efficient management and use of the spectrum based on cognitive radio technology. The ability of cognitive radio technologies to adapt to the real-time conditions of its operating environment, offers the potential for more flexible use of the available spectrum. In this context, the international interest is particularly focused on the “white spaces” in the UHF band of digital terrestrial television. Spectrum sensing and geo-location da...

  14. Mechanisms of enhanced HIV spread through T-cell virological synapses.

    Science.gov (United States)

    Dale, Benjamin M; Alvarez, Raymond A; Chen, Benjamin K

    2013-01-01

    An elaborate network of cell-cell interactions in the immune system is essential for vertebrates to mount adaptive immune responses against invading pathogens. For lymphotropic viruses such as the human immunodeficiency virus type 1 (HIV-1), these immune cell interactions can also promote the spread of the virus within the host. The main target of HIV-1 infection is the CD4(+) helper T lymphocyte, a cell type that is responsible for coordinating immune responses and modulating effector responses to foreign antigens. As part of their normal immune surveillance duties, these cells migrate actively within lymphoid tissues and can travel from inductive sites to effector sites in search of their cognate antigen. For CD4(+) T cells, there is an ongoing search for a unique peptide antigen presented in the context of class II MHC that can activate a proliferative or tolerogenic response. This iterative and continual probing and interrogation of other cells determine the outcome of immune responses. Recent studies in vitro have revealed that the viral infection program induces cell-cell interactions called virological synapses between infected and uninfected CD4(+) T cells. These long-lived, virally induced adhesive contacts greatly enhance the rate of productive infection and may be central to the spread of the virus in vivo. Here, we review aspects of this efficient mode of cell-to-cell infection and the implications for our understanding of HIV-1 pathogenesis. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

  15. Novel formulation for enhancing efficiency of metribuzin.

    Science.gov (United States)

    Karakotov, S D; Zheltova, E V; Putsykin, Yu G; Balakin, K V; Shapovalov, A A

    2006-01-01

    The biological efficiency of systemic herbicide metribuzin in water dispersible granules (WG) and solution colloid concentrate (SCC) formulations was studied in field experiments. Metribuzin formulation in SCC state was prepared by the addition of a mixture of anionic and non-ionic surfactants and alkoxylated sorbitan esters as specific adjuvants. The ability of herbicide formulation containing Metribuzin in SCC state to provide increases in control of broadleaf and grassy weeds in comparison to WG was observed. The possibility to reduce application rate of Metribuzin from high-dose to low-dose without losing efficacy of weed control was demonstrated.

  16. Intuitive information technology: enhancing clinician efficiency.

    Science.gov (United States)

    Procuniar, Molly; Murphy, Sue

    2008-11-06

    Although medical technology is making great strides in improved diagnosis and treatment, the technologies used to document, communicate, and manage those activities are limiting its progress by converting clinicians into computer operators. In an environment of nurse and doctor shortages, reducing their efficiency is counter productive. Technology in healthcare that does not serve patients by improving cost, quality, or care delivery is technology that serves no purpose. Requiring clinicians to chart away from the bedside using technologies that do not feel intuitive, such as keyboarding and mouse use reduces efficiency of workflow, impedes direct care, and increases the cost of training. Intuitive forms of technology such as surface technology, voice activated charting, or digital pens, if embraced, could cause significant changes in healthcare workflows. Clinicians could be more focused on direct care and less utilized in clerical activity. The time it takes to access information could be decreased exponentially--and the opportunities to interact with that information would present a nearly endless horizon. This impact would be especially crucial in high acuity areas and emergency patient care situations. In short, technology should embrace familiar, natural movements and develop intuitive interfaces to improve effectiveness in the healthcare market of the future.

  17. Is there scope for cost savings and efficiency gains in HIV services? A systematic review of the evidence from low- and middle-income countries.

    Science.gov (United States)

    Siapka, Mariana; Remme, Michelle; Obure, Carol Dayo; Maier, Claudia B; Dehne, Karl L; Vassall, Anna

    2014-07-01

    To synthesize the data available--on costs, efficiency and economies of scale and scope--for the six basic programmes of the UNAIDS Strategic Investment Framework, to inform those planning the scale-up of human immunodeficiency virus (HIV) services in low- and middle-income countries. The relevant peer-reviewed and "grey" literature from low- and middle-income countries was systematically reviewed. Search and analysis followed Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Of the 82 empirical costing and efficiency studies identified, nine provided data on economies of scale. Scale explained much of the variation in the costs of several HIV services, particularly those of targeted HIV prevention for key populations and HIV testing and treatment. There is some evidence of economies of scope from integrating HIV counselling and testing services with several other services. Cost efficiency may also be improved by reducing input prices, task shifting and improving client adherence. HIV programmes need to optimize the scale of service provision to achieve efficiency. Interventions that may enhance the potential for economies of scale include intensifying demand-creation activities, reducing the costs for service users, expanding existing programmes rather than creating new structures, and reducing attrition of existing service users. Models for integrated service delivery--which is, potentially, more efficient than the implementation of stand-alone services--should be investigated further. Further experimental evidence is required to understand how to best achieve efficiency gains in HIV programmes and assess the cost-effectiveness of each service-delivery model.

  18. DC-SIGN-mediated infectious synapse formation enhances X4 HIV-1 transmission from dendritic cells to T cells

    NARCIS (Netherlands)

    Arrighi, Jean-François; Pion, Marjorie; Garcia, Eduardo; Escola, Jean-Michel; van Kooyk, Yvette; Geijtenbeek, Teunis B.; Piguet, Vincent

    2004-01-01

    Dendritic cells (DCs) are essential for the early events of human immunodeficiency virus (HIV) infection. Model systems of HIV sexual transmission have shown that DCs expressing the DC-specific C-type lectin DC-SIGN capture and internalize HIV at mucosal surfaces and efficiently transfer HIV to CD4+

  19. Efficient inhibition of HIV-1 replication by an artificial polycistronic miRNA construct

    Directory of Open Access Journals (Sweden)

    Zhang Tao

    2012-06-01

    Full Text Available Abstract Background RNA interference (RNAi has been used as a promising approach to inhibit human immunodeficiency virus type 1 (HIV-1 replication for both in vitro and in vivo animal models. However, HIV-1 escape mutants after RNAi treatment have been reported. Expressing multiple small interfering RNAs (siRNAs against conserved viral sequences can serve as a genetic barrier for viral escape, and optimization of the efficiency of this process was the aim of this study. Results An artificial polycistronic transcript driven by a CMV promoter was designed to inhibit HIV-1 replication. The artificial polycistronic transcript contained two pre-miR-30a backbones and one pre-miR-155 backbone, which are linked by a sequence derived from antisense RNA sequence targeting the HIV-1 env gene. Our results demonstrated that this artificial polycistronic transcript simultaneously expresses three anti-HIV siRNAs and efficiently inhibits HIV-1 replication. In addition, the biosafety of MT-4 cells expressing this polycistronic miRNA transcript was evaluated, and no apparent impacts on cell proliferation rate, interferon response, and interruption of native miRNA processing were observed. Conclusions The strategy described here to generate an artificial polycistronic transcript to inhibit viral replication provided an opportunity to select and optimize many factors to yield highly efficient constructs expressing multiple siRNAs against viral infection.

  20. HealthCall for the smartphone: technology enhancement of brief intervention in HIV alcohol dependent patients

    OpenAIRE

    Hasin, Deborah S; Aharonovich, Efrat; Greenstein, Eliana

    2014-01-01

    Background Heavy drinking jeopardizes the health of patients in HIV primary care. In alcohol dependent patients in HIV primary care, a technological enhancement of brief intervention, HealthCall administered via interactive voice response (HealthCall-IVR) was effective at reducing heavy drinking. The smartphone offered a technology platform to improve HealthCall. Methods Working with input from patients, technology experts, and HIV clinic personnel, we further developed HealthCall, harnessing...

  1. A Comprehensive HIV Stigma-reduction and Wellness-enhancement Community Intervention: A Case Study.

    NARCIS (Netherlands)

    French, H.; Greeff, M.; Watson, M.J.; Doak, C.M.

    2014-01-01

    We describe the implementation of a comprehensive HIV stigma-reduction and wellness-enhancement community intervention that focused on people living with HIV (PLWH), as well as people living close to them (PLC) from six designated groups. A holistic multiple case study design was used in urban and

  2. HIV screening at health facilities and community pharmacies in Kenya : Enhancing test uptake and early diagnosis

    NARCIS (Netherlands)

    Mugo, P.M.

    2017-01-01

    Despite a tremendous scale-up of antiretroviral therapy, as many as 54% of HIV-infected persons globally remain undiagnosed hence are not on treatment. This thesis presents findings from a series of studies conducted in Coastal Kenya aiming to enhance HIV test uptake and early diagnosis. We found

  3. 77 FR 41190 - Office of Clinical and Preventive Services Funding Opportunity: National HIV Program for Enhanced...

    Science.gov (United States)

    2012-07-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Indian Health Service Office of Clinical and Preventive Services Funding Opportunity: National HIV Program for Enhanced HIV/AIDS Screening and Engagement in Care AGENCY: Indian Health Service...

  4. Enhancing School HIV and AIDS Strategic Plan through Expanded Stakeholder Involvement

    Science.gov (United States)

    Mgomezulu, V. Y.; Kruger, A. G.

    2011-01-01

    This article focuses on the need for expanded stakeholder involvement as a means of enhancing the Botswana Department of Secondary Education (DSE) HIV and AIDS strategic plan. Research has indicated that the effects of HIV and AIDS on the supply of and demand for education are considerable. Using a questionnaire and interviews, the research has…

  5. Herpes simplex virus type 2 enhances HIV-1 susceptibility by affecting langerhans cell function

    NARCIS (Netherlands)

    M.A.W.P. de Jong (Marein); L. de Witte (Lot); M.E. Taylor (Maureen); T.B.H. Geijtenbeek (Teunis)

    2010-01-01

    textabstractGenital herpes is the most prevalent viral sexually transmitted infection worldwide and is mainly caused by HSV type 2 (HSV-2). HSV-2 infection enhances HIV-1 susceptibility, even in the absence of clinical symptoms. In this study, we investigated the effect of HSV-2 on HIV-1

  6. Opportunities for improving the efficiency of paediatric HIV treatment programmes

    OpenAIRE

    Revill, Paul A.; Walker, Simon; Mabugu, Travor; Nathoo, Kusum J.; Mugyenyi, Peter; Kekitinwa, Adeodata; Munderi, Paula; Bwakura-Dangarembizi, Mutsawashe; Musiime, Victor; Bakeera-Kitaka, Sabrina; NAHIRYA-NTEGE, Patricia; Walker, A. Sarah; Sculpher, Mark J; Gibb, Diana M.

    2015-01-01

    Objectives: To conduct two economic analyses addressing whether to: routinely monitor HIV-infected children on antiretroviral therapy (ART) clinically or with laboratory tests; continue or stop cotrimoxazole prophylaxis when children become stabilized on ART. Design and methods: The ARROW randomized trial investigated alternative strategies to deliver paediatric ART and cotrimoxazole prophylaxis in 1206 Ugandan/Zimbabwean children. Incremental cost-effectiveness and value of implementation an...

  7. Change-over-time : a comprehensive community-based HIV stigma reduction and wellness enhancement intervention / Helena Christa Chidrawi

    OpenAIRE

    Chidrawi, Helena Christa

    2014-01-01

    This study forms part of a larger SANPAD project focusing on a comprehensive community-based HIV stigma reduction and wellness enhancement intervention, responding to the continuous burden of HIV stigma on both national and international levels and the paucity of research in sustainable HIV stigma reduction interventions. HIV stigma is considered all over the world as a complex, far-reaching and powerful phenomenon that continues to affect people living with HIV (PLWH) and also people living ...

  8. The Fc and not CD4 Receptor Mediates Antibody Enhancement of HIV Infection in Human Cells

    Science.gov (United States)

    Homsy, Jacques; Meyer, Mia; Tateno, Masatoshi; Clarkson, Sarah; Levy, Jay A.

    1989-06-01

    Antibodies that enhance human immunodeficiency virus (HIV) infectivity have been found in the blood of infected individuals and in infected or immunized animals. These findings raise serious concern for the development of a safe vaccine against acquired immunodeficiency syndrome. To address the in vivo relevance and mechanism of this phenomenon, antibody-dependent enhancement of HIV infectivity in peripheral blood macrophages, lymphocytes, and human fibroblastoid cells was studied. Neither Leu3a, a monoclonal antibody directed against the CD4 receptor, nor soluble recombinant CD4 even at high concentrations prevented this enhancement. The addition of monoclonal antibody to the Fc receptor III (anti-FcRIII), but not of antibodies that react with FcRI or FcRII, inhibited HIV type 1 and HIV type 2 enhancement in peripheral blood macrophages. Although enhancement of HIV infection in CD4+ lymphocytes could not be blocked by anti-FcRIII, it was inhibited by the addition of human immunoglobulin G aggregates. The results indicate that the FcRIII receptor on human macrophages and possibly another Fc receptor on human CD4+ lymphocytes mediate antibody-dependent enhancement of HIV infectivity and that this phenomenon proceeds through a mechanism independent of the CD4 protein.

  9. Dependence of АRT efficiency from the infection route in HIV infected patients

    Directory of Open Access Journals (Sweden)

    D. H. Zhyvytsia

    2017-06-01

    Full Text Available The most rapid growth rate of the epidemic process of HIV in Ukraine is observed among injection drug users (IDUs. Substitution maintenance therapy (SMT with methadone and buprenorphine significantly increases the patients’ maintenance in treatment due to increased adherence to antiretroviral therapy (ART, which is a mandatory component of comprehensive medical care for HIV-infected. The aim of our study was to determine the impact of SMT on the efficiency of ART for IDUs with HIV infection compared with patients infected through sexual contact. Materials and methods. The study included 95 patients with HIV that were divided into three groups. The first group included 33 IDUs patients who were treated with SMT. The second group included 32 IDUs patients without SMT. The third group included 30 patients with the sexual way of HIV infection. After the inclusion into the research all the patients were prescribed ART. Immunological examination and determination of viral load were carried out before the appointment of ART after 6 and 12 months during the treatment. Results and discussion. During the treatment with ART harder immunosuppression was recorded in the second group of patients, while the average viral load did not statistically differ in the research groups. After 6 months of the treatment the increase (P <0.05 of the number of CD4-lymphocytes was noted in all groups of patients, and the proportion of patients with full suppression of HIV in the first and the third groups was higher than in the second group, however this difference was not significant. After 12 months of the treatment, there was a further increase (P <0.05 of the absolute number of CD4-lymphocytes in the research groups, and in the virological efficiency of ART assessing a significantly higher (P <0.01 percentage was found in patients of the first and the third groups, who achieved the full viral suppression. It should be noted, that within 6-12 months of the treatment

  10. Quantitative effect of suboptimal codon usage on translational efficiency of mRNA encoding HIV-1 gag in intact T cells.

    Directory of Open Access Journals (Sweden)

    Kholiswa C Ngumbela

    Full Text Available BACKGROUND: The sequences of wild-isolate strains of Human Immunodeficiency Virus-1 (HIV-1 are characterized by low GC content and suboptimal codon usage. Codon optimization of DNA vectors can enhance protein expression both by enhancing translational efficiency, and by altering RNA stability and export. Although gag codon optimization is widely used in DNA vectors and experimental vaccines, the actual effect of altered codon usage on gag translational efficiency has not been quantified. METHODOLOGY AND PRINCIPAL FINDINGS: To quantify translational efficiency of gag mRNA in live T cells, we transfected Jurkat cells with increasing doses of capped, polyadenylated synthetic mRNA corresponding to wildtype or codon-optimized gag sequences, measured Gag production by quantitative ELISA and flow cytometry, and estimated the translational efficiency of each transcript as pg of Gag antigen produced per microg of input mRNA. We found that codon optimization yielded a small increase in gag translational efficiency (approximately 1.6 fold. In contrast when cells were transfected with DNA vectors requiring nuclear transcription and processing of gag mRNA, codon optimization resulted in a very large enhancement of Gag production. CONCLUSIONS: We conclude that suboptimal codon usage by HIV-1 results in only a slight loss of gag translational efficiency per se, with the vast majority of enhancement in protein expression from DNA vectors due to altered processing and export of nuclear RNA.

  11. Quantitative effect of suboptimal codon usage on translational efficiency of mRNA encoding HIV-1 gag in intact T cells.

    Science.gov (United States)

    Ngumbela, Kholiswa C; Ryan, Kieran P; Sivamurthy, Rohini; Brockman, Mark A; Gandhi, Rajesh T; Bhardwaj, Nina; Kavanagh, Daniel G

    2008-06-04

    The sequences of wild-isolate strains of Human Immunodeficiency Virus-1 (HIV-1) are characterized by low GC content and suboptimal codon usage. Codon optimization of DNA vectors can enhance protein expression both by enhancing translational efficiency, and by altering RNA stability and export. Although gag codon optimization is widely used in DNA vectors and experimental vaccines, the actual effect of altered codon usage on gag translational efficiency has not been quantified. To quantify translational efficiency of gag mRNA in live T cells, we transfected Jurkat cells with increasing doses of capped, polyadenylated synthetic mRNA corresponding to wildtype or codon-optimized gag sequences, measured Gag production by quantitative ELISA and flow cytometry, and estimated the translational efficiency of each transcript as pg of Gag antigen produced per microg of input mRNA. We found that codon optimization yielded a small increase in gag translational efficiency (approximately 1.6 fold). In contrast when cells were transfected with DNA vectors requiring nuclear transcription and processing of gag mRNA, codon optimization resulted in a very large enhancement of Gag production. We conclude that suboptimal codon usage by HIV-1 results in only a slight loss of gag translational efficiency per se, with the vast majority of enhancement in protein expression from DNA vectors due to altered processing and export of nuclear RNA.

  12. Enhancing HIV status disclosure and partners' testing through ...

    African Journals Online (AJOL)

    Background: In Tanzania HIV Testing and Counselling (HTC) is being implemented through voluntary counselling and testing (VCT), provider initiated counselling and testing (PITC) and work place counselling and testing (HTC). Within these programmes, HIV status disclosure is emphasized. However, among persons who ...

  13. An efficient procedure for the expression and purification of HIV-1 protease from inclusion bodies.

    Science.gov (United States)

    Nguyen, Hong-Loan Thi; Nguyen, Thuy Thi; Vu, Quy Thi; Le, Hang Thi; Pham, Yen; Trinh, Phuong Le; Bui, Thuan Phuong; Phan, Tuan-Nghia

    2015-12-01

    Several studies have focused on HIV-1 protease for developing drugs for treating AIDS. Recombinant HIV-1 protease is used to screen new drugs from synthetic compounds or natural substances. However, large-scale expression and purification of this enzyme is difficult mainly because of its low expression and solubility. In this study, we constructed 9 recombinant plasmids containing a sequence encoding HIV-1 protease along with different fusion tags and examined the expression of the enzyme from these plasmids. Of the 9 plasmids, pET32a(+) plasmid containing the HIV-1 protease-encoding sequence along with sequences encoding an autocleavage site GTVSFNF at the N-terminus and TEV plus 6× His tag at the C-terminus showed the highest expression of the enzyme and was selected for further analysis. The recombinant protein was isolated from inclusion bodies by using 2 tandem Q- and Ni-Sepharose columns. SDS-PAGE of the obtained HIV-1 protease produced a single band of approximately 13 kDa. The enzyme was recovered efficiently (4 mg protein/L of cell culture) and had high specific activity of 1190 nmol min(-1) mg(-1) at an optimal pH of 4.7 and optimal temperature of 37 °C. This procedure for expressing and purifying HIV-1 protease is now being scaled up to produce the enzyme on a large scale for its application. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Photovoltaic cell with light trapping for enhanced efficiency

    Science.gov (United States)

    Brener, Igal; Fofang, Nche Tumasang; Luk, Ting S.

    2015-11-19

    The efficiency of a photovoltaic cell is enhanced by light trapping using Mie-scattering nanostructures. In one embodiment, an array of nanocylinders is formed on the front surface of a silicon film to enhance forward scattering into the film, and an array of nanocylinders is formed on the back surface to enhance backscattering so that more light is absorbed within the silicon film. In an alternate embodiment, a mirror layer is formed on the back surface of the silicon film to reflect light within the film back toward the front-surface nanocylinder array.

  15. A simple and efficient procedure to enhance artemisinin content in ...

    African Journals Online (AJOL)

    Artemisinin is an effective anti-malarial drug extracted from Artemisia annua L. Due to the low content of artemisinin in A. annua, great efforts have been devoted to improve artemisinin production. Here we report a simple and efficient procedure to enhance artemisinin content in A. annua by seeding to salinity stress.

  16. Shared Services for enhancing municipal planning efficiency in ...

    African Journals Online (AJOL)

    The past five years have seen a growing trend towards the notion of a Shared Services approach to enhancing municipal efficiency in the local government sector in South Africa. In KwaZulu-Natal (KZN), this approach is receiving more focused attention. In this regard, the Department of Co-operative Governance and ...

  17. Efficient Vpu-Mediated Tetherin Antagonism by an HIV-1 Group O Strain.

    Science.gov (United States)

    Mack, Katharina; Starz, Kathrin; Sauter, Daniel; Langer, Simon; Bibollet-Ruche, Frederic; Learn, Gerald H; Stürzel, Christina M; Leoz, Marie; Plantier, Jean-Christophe; Geyer, Matthias; Hahn, Beatrice H; Kirchhoff, Frank

    2017-03-15

    Simian immunodeficiency viruses (SIVs) use their Nef proteins to counteract the restriction factor tetherin. However, a deletion in human tetherin prevents antagonism by the Nef proteins of SIVcpz and SIVgor, which represent the ape precursors of human immunodeficiency virus type 1 (HIV-1). To promote virus release from infected cells, pandemic HIV-1 group M strains evolved Vpu as a tetherin antagonist, while the Nef protein of less widespread HIV-1 group O strains acquired the ability to target a region adjacent to this deletion. In this study, we identified an unusual HIV-1 group O strain (RBF206) that evolved Vpu as an effective antagonist of human tetherin. While both RBF206 Vpu and Nef exert anti-tetherin activity in transient-transfection assays, mainly Vpu promotes RBF206 release in infected CD4(+) T cells. Although mutations distinct from the adaptive changes observed in group M Vpus (M-Vpus) were critical for the acquisition of its anti-tetherin activity, RBF206 O-Vpu potently suppresses NF-κB activation and reduces CD4 cell surface expression. Interestingly, RBF206 Vpu counteracts tetherin in a largely species-independent manner, degrading both the long and short isoforms of human tetherin. Downmodulation of CD4, but not counteraction of tetherin, by RBF206 Vpu was dependent on the cellular ubiquitin ligase machinery. Our data present the first example of an HIV-1 group O Vpu that efficiently antagonizes human tetherin and suggest that counteraction by O-Nefs may be suboptimal.IMPORTANCE Previous studies showed that HIV-1 groups M and O evolved two alternative strategies to counteract the human ortholog of the restriction factor tetherin. While HIV-1 group M switched from Nef to Vpu due to a deletion in the cytoplasmic domain of human tetherin, HIV-1 group O, which lacks Vpu-mediated anti-tetherin activity, acquired a Nef protein that is able to target a region adjacent to the deletion. Here we report an unusual exception, identifying a strain of HIV-1

  18. Relative Efficiency of Field and Online Strategies in the Recruitment of HIV-Positive Men Who Have Sex With Men.

    Science.gov (United States)

    Vial, Andrea C; Starks, Tyrel J; Parsons, Jeffrey T

    2015-04-01

    Efforts to reach HIV-positive men who have sex with men (MSM) and link them to care must be expanded; however, finding and recruiting them remains a challenge. We compared the efficiency of three recruitment sources in reaching self-identified HIV-positive MSM with various characteristics. Relative to recruitment online and at clubs and bars, AIDS Service Organizations (ASOs) were significantly more efficient in reaching HIV-positive MSM in general. This was also true for those with specific characteristics of interest such as substance/stimulant use, and HIV-positive MSM who were racial/ethnic minorities. Both ASOs and online recruitment were more efficient than clubs and bars in reaching HIV-positive MSM not taking HIV medication. This was also the case for White HIV-positive MSM in general, and White HIV-positive MSM who used substances and stimulants. Online recruitment was also more efficient than clubs and bars in reaching HIV-positive MSM who were young across the board.

  19. Enhanced prenatal HIV couple oriented counselling session and couple communication about HIV (ANRS 12127 Prenahtest Trial)

    NARCIS (Netherlands)

    Plazy, M.; Orne-Gliemann, J.; Balestre, E.; Miric, M.; Darak, S.; Butsashvili, M.; Tchendjou, P.; Dabis, F.; du Lou, A. Desgrees

    Background. - The Prenahtest study investigated the efficacy of a couple-oriented HIV counselling session (COC) in encouraging couple HIV counselling and testing, and improving intra-couple communication about sexual and reproductive health. We report here on the effect of COC on intra-couple

  20. Enhancing HIV Treatment Access and Outcomes Amongst HIV Infected Children and Adolescents in Resource Limited Settings.

    Science.gov (United States)

    Goga, Ameena Ebrahim; Singh, Yagespari; Singh, Michelle; Noveve, Nobuntu; Magasana, Vuyolwethu; Ramraj, Trisha; Abdullah, Fareed; Coovadia, Ashraf H; Bhardwaj, Sanjana; Sherman, Gayle G

    2017-01-01

    Introduction Increasing access to HIV-related care and treatment for children aged 0-18 years in resource-limited settings is an urgent global priority. In 2011-2012 the percentage increase in children accessing antiretroviral therapy was approximately half that of adults (11 vs. 21 %). We propose a model for increasing access to, and retention in, paediatric HIV care and treatment in resource-limited settings. Methods Following a rapid appraisal of recent literature seven main challenges in paediatric HIV-related care and treatment were identified: (1) lack of regular, integrated, ongoing HIV-related diagnosis; (2) weak facility-based systems for tracking and retention in care; (3) interrupted availability of dried blood spot cards (expiration/stock outs); (4) poor quality control of rapid HIV testing; (5) supply-related gaps at health facility-laboratory interface; (6) poor uptake of HIV testing, possibly relating to a fatalistic belief about HIV infection; (7) community-associated reasons e.g. non-disclosure and weak systems for social support, resulting in poor retention in care. Results To increase sustained access to paediatric HIV-related care and treatment, regular updating of Policies, review of inter-sectoral Plans (at facility and community levels) and evaluation of Programme implementation and impact (at national, subnational, facility and community levels) are non-negotiable critical elements. Additionally we recommend the intensified implementation of seven main interventions: (1) update or refresher messaging for health care staff and simple messaging for key staff at early childhood development centres and schools; (2) contact tracing, disclosure and retention monitoring; (3) paying particular attention to infant dried blood spot (DBS) stock control; (4) regular quality assurance of rapid HIV testing procedures; (5) workshops/meetings/dialogues between health facilities and laboratories to resolve transport-related gaps and to facilitate return of

  1. Materials That Enhance Efficiency and Radiation Resistance of Solar Cells

    Science.gov (United States)

    Sun, Xiadong; Wang, Haorong

    2012-01-01

    A thin layer (approximately 10 microns) of a novel "transparent" fluorescent material is applied to existing solar cells or modules to effectively block and convert UV light, or other lower solar response waveband of solar radiation, to visible or IR light that can be more efficiently used by solar cells for additional photocurrent. Meanwhile, the layer of fluorescent coating material remains fully "transparent" to the visible and IR waveband of solar radiation, resulting in a net gain of solar cell efficiency. This innovation alters the effective solar spectral power distribution to which an existing cell gets exposed, and matches the maximum photovoltaic (PV) response of existing cells. By shifting a low PV response waveband (e.g., UV) of solar radiation to a high PV response waveband (e.g. Vis-Near IR) with novel fluorescent materials that are transparent to other solar-cell sensitive wavebands, electrical output from solar cells will be enhanced. This approach enhances the efficiency of solar cells by converting UV and high-energy particles in space that would otherwise be wasted to visible/IR light. This innovation is a generic technique that can be readily implemented to significantly increase efficiencies of both space and terrestrial solar cells, without incurring much cost, thus bringing a broad base of economical, social, and environmental benefits. The key to this approach is that the "fluorescent" material must be very efficient, and cannot block or attenuate the "desirable" and unconverted" waveband of solar radiation (e.g. Vis-NIR) from reaching the cells. Some nano-phosphors and novel organometallic complex materials have been identified that enhance the energy efficiency on some state-of-the-art commercial silicon and thin-film-based solar cells by over 6%.

  2. HIV-1 Tat potently stabilises Mdm2 and enhances viral replication.

    Science.gov (United States)

    Raja, Rameez; Ronsard, Larance; Lata, Sneh; Trivedi, Shubhendu; Banerjea, Akhil C

    2017-07-11

    Murine double minute 2 (Mdm2) is known to enhance the transactivation potential of human immunodeficiency virus (HIV-1) Tat protein by causing its ubiquitination. However, the regulation of Mdm2 during HIV-1 infection and its implications for viral replication have not been well studied. Here, we show that the Mdm2 protein level increases during HIV-1 infection and this effect is mediated by HIV-1 Tat protein. Tat appears to stabilise Mdm2 at the post-translational level by inducing its phosphorylation at serine-166 position through AKT. Although p53 is one of the key players for Mdm2 induction, Tat-mediated stabilisation of Mdm2 appears to be independent of p53. Moreover, the non-phosphorylatable mutant of Mdm2 (S166A) fails to interact with Tat and shows decreased half-life in the presence of Tat compared with wild-type Mdm2. Furthermore, the non-phosphorylatable mutant of Mdm2 (S166A) is unable to support HIV-1 replication. Thus, HIV-1 Tat appears to stabilise Mdm2, which in turn enhances Tat-mediated viral replication. This study highlights the importance of post-translational modifications of host cellular factors in HIV-1 replication and pathogenesis. © 2017 The Author(s).

  3. Enhancing Solar Cell Efficiencies through 1-D Nanostructures

    Directory of Open Access Journals (Sweden)

    Yu Kehan

    2008-01-01

    Full Text Available Abstract The current global energy problem can be attributed to insufficient fossil fuel supplies and excessive greenhouse gas emissions resulting from increasing fossil fuel consumption. The huge demand for clean energy potentially can be met by solar-to-electricity conversions. The large-scale use of solar energy is not occurring due to the high cost and inadequate efficiencies of existing solar cells. Nanostructured materials have offered new opportunities to design more efficient solar cells, particularly one-dimensional (1-D nanomaterials for enhancing solar cell efficiencies. These 1-D nanostructures, including nanotubes, nanowires, and nanorods, offer significant opportunities to improve efficiencies of solar cells by facilitating photon absorption, electron transport, and electron collection; however, tremendous challenges must be conquered before the large-scale commercialization of such cells. This review specifically focuses on the use of 1-D nanostructures for enhancing solar cell efficiencies. Other nanostructured solar cells or solar cells based on bulk materials are not covered in this review. Major topics addressed include dye-sensitized solar cells, quantum-dot-sensitized solar cells, and p-n junction solar cells.

  4. Identification of unique reciprocal and non reciprocal cross packaging relationships between HIV-1, HIV-2 and SIV reveals an efficient SIV/HIV-2 lentiviral vector system with highly favourable features for in vivo testing and clinical usage

    Directory of Open Access Journals (Sweden)

    Caldwell Maeve

    2005-09-01

    Full Text Available Abstract Background Lentiviral vectors have shown immense promise as vehicles for gene delivery to non-dividing cells particularly to cells of the central nervous system (CNS. Improvements in the biosafety of viral vectors are paramount as lentiviral vectors move into human clinical trials. This study investigates the packaging relationship between gene transfer (vector and Gag-Pol expression constructs of HIV-1, HIV-2 and SIV. Cross-packaged vectors expressing GFP were assessed for RNA packaging, viral vector titre and their ability to transduce rat primary glial cell cultures and human neural stem cells. Results HIV-1 Gag-Pol demonstrated the ability to cross package both HIV-2 and SIV gene transfer vectors. However both HIV-2 and SIV Gag-Pol showed a reduced ability to package HIV-1 vector RNA with no significant gene transfer to target cells. An unexpected packaging relationship was found to exist between HIV-2 and SIV with SIV Gag-Pol able to package HIV-2 vector RNA and transduce dividing SV2T cells and CNS cell cultures with an efficiency equivalent to the homologous HIV-1 vector however HIV-2 was unable to deliver SIV based vectors. Conclusion This new non-reciprocal cross packaging relationship between SIV and HIV-2 provides a novel way of significantly increasing bio-safety with a reduced sequence homology between the HIV-2 gene transfer vector and the SIV Gag-Pol construct thus ensuring that vector RNA packaging is unidirectional.

  5. Determinants in HIV-1 Nef for enhancement of virus replication and depletion of CD4+ T lymphocytes in human lymphoid tissue ex vivo

    Directory of Open Access Journals (Sweden)

    Sertel Serkan

    2009-01-01

    Full Text Available Abstract Background HIV-1 Nef critically contributes to AIDS in part by augmenting virus titers in infected individuals. Analyzing which of Nef's activities contribute to HIV pathogenesis has been hampered by the lack of a cell culture model in which Nef exerts pronounced effects on HIV replication. The human lymphoid aggregate culture (HLAC from tonsil maintains the cell populations and cytokine milieu found in vivo, supports a productive infection without exogenous stimulation, and Nef contributes to efficient HIV-1 replication as well as CD4+ T cell depletion in this experimental ex vivo-model. Results To identify determinants in Nef that mediate these activities, we infected HLAC with a panel of isogenic HIV-1NL4-3 strains that encode for well-characterized mutants of HIV-1SF2 Nef. Determination of HIV-1 replication revealed that enhancement of the virus spread by Nef is governed by a complex set of protein interaction surfaces. In contrast, increased CD4+ T lymphocyte depletion depended on only two protein interaction surfaces in Nef that mediate either downregulation of cell surface CD4 or interaction with the NAKC signalosome. Consistently, in HLAC from 9 out of 14 donors, Nef enhanced CD4+ T cell depletion in the absence of a significant effect on virus replication. Moreover, our results suggest that this Nef-dependent enhancement in depletion occurred predominately in uninfected bystander CD4+ T cells. Conclusion Our findings suggest that Nef facilitates depletion of CD4+ T lymphocytes in HIV-1-infected lymphoid tissue ex vivo by increasing the pool of productively infected cells and by sensitizing bystander cells for killing. This ability might contribute to Nef's pathogenic potential in vivo.

  6. Human prostate supports more efficient replication of HIV-1 R5 than X4 strains ex vivo

    Directory of Open Access Journals (Sweden)

    Denis Hélène

    2008-12-01

    Full Text Available Abstract Background In order to determine whether human prostate can be productively infected by HIV-1 strains with different tropism, and thus represent a potential source of HIV in semen, an organotypic culture of prostate from men undergoing prostatic adenomectomy for benign prostate hypertrophy (BPH was developed. The presence of potential HIV target cells in prostate tissues was investigated using immunohistochemistry. The infection of prostate explants following exposures with HIV-1 R5, R5X4 and X4 strains was analyzed through the measure of RT activity in culture supernatants, the quantification of HIV DNA in the explants and the detection of HIV RNA+ cells in situ. Results The overall prostate characteristics were retained for 21/2 weeks in culture. Numerous potential HIV-1 target cells were detected in the prostate stroma. Whilst HIV-1 R5SF162 strain consistently productively infected prostatic T lymphocytes and macrophages, the prototypic X4IIIB strain and a primary R5X4 strain showed less efficient replication in this organ. Conclusion The BPH prostate is a site of HIV-1 R5 replication that could contribute virus to semen. A limited spreading of HIV-1 X4 and R5X4 in this organ could participate to the preferential sexual transmission of HIV-1 R5 strains.

  7. Human prostate supports more efficient replication of HIV-1 R5 than X4 strains ex vivo.

    Science.gov (United States)

    Le Tortorec, Anna; Satie, Anne-Pascale; Denis, Hélène; Rioux-Leclercq, Nathalie; Havard, Laurence; Ruffault, Annick; Jégou, Bernard; Dejucq-Rainsford, Nathalie

    2008-12-31

    In order to determine whether human prostate can be productively infected by HIV-1 strains with different tropism, and thus represent a potential source of HIV in semen, an organotypic culture of prostate from men undergoing prostatic adenomectomy for benign prostate hypertrophy (BPH) was developed. The presence of potential HIV target cells in prostate tissues was investigated using immunohistochemistry. The infection of prostate explants following exposures with HIV-1 R5, R5X4 and X4 strains was analyzed through the measure of RT activity in culture supernatants, the quantification of HIV DNA in the explants and the detection of HIV RNA+ cells in situ. The overall prostate characteristics were retained for 21/2 weeks in culture. Numerous potential HIV-1 target cells were detected in the prostate stroma. Whilst HIV-1 R5SF162 strain consistently productively infected prostatic T lymphocytes and macrophages, the prototypic X4IIIB strain and a primary R5X4 strain showed less efficient replication in this organ. The BPH prostate is a site of HIV-1 R5 replication that could contribute virus to semen. A limited spreading of HIV-1 X4 and R5X4 in this organ could participate to the preferential sexual transmission of HIV-1 R5 strains.

  8. Lithographic antennas for enhancement of solar cell efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Kotter, D.K. [Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States); Boreman, G. [Univ. of Central Florida, Orlando, FL (United States). Center for Research and Education in Optics and Lasers

    1998-04-01

    This report documents proof-of-concept demonstration of the use of lithographic antennas for enhancement of solar-cell efficiency. A micro-sized lithographic antenna array was theoretically modeled, designed and fabricated. Experimental research was performed to validate the ability of the antenna array to concentrate infrared and visible energy onto photovoltaic (PV) materials. The research will serve as the basis for the design of a miniature power source for remote sensors.

  9. Unpolarized release of vaccinia virus and HIV antigen by colchicine treatment enhances intranasal HIV antigen expression and mucosal humoral responses.

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    Full Text Available The induction of a strong mucosal immune response is essential to building successful HIV vaccines. Highly attenuated recombinant HIV vaccinia virus can be administered mucosally, but even high doses of immunization have been found unable to induce strong mucosal antibody responses. In order to solve this problem, we studied the interactions of recombinant HIV vaccinia virus Tiantan strain (rVTT-gagpol in mucosal epithelial cells (specifically Caco-2 cell layers and in BALB/c mice. We evaluated the impact of this virus on HIV antigen delivery and specific immune responses. The results demonstrated that rVTT-gagpol was able to infect Caco-2 cell layers and both the nasal and lung epithelia in BALB/c mice. The progeny viruses and expressed p24 were released mainly from apical surfaces. In BALB/c mice, the infection was limited to the respiratory system and was not observed in the blood. This showed that polarized distribution limited antigen delivery into the whole body and thus limited immune response. To see if this could be improved upon, we stimulated unpolarized budding of the virus and HIV antigens by treating both Caco-2 cells and BALB/c mice with colchicine. We found that, in BALB/c mice, the degree of infection and antigen expression in the epithelia went up. As a result, specific immune responses increased correspondingly. Together, these data suggest that polarized budding limits antigen delivery and immune responses, but unpolarized distribution can increase antigen expression and delivery and thus enhance specific immune responses. This conclusion can be used to optimize mucosal HIV vaccine strategies.

  10. Cocaine enhances HIV-1 gp120-induced lymphatic endothelial dysfunction in the lung.

    Science.gov (United States)

    Zhang, Xuefeng; Jiang, Susan; Yu, Jinlong; Kuzontkoski, Paula M; Groopman, Jerome E

    2015-08-01

    Pulmonary complications are common in both AIDS patients and cocaine users. We addressed the cellular and molecular mechanisms by which HIV and cocaine may partner to induce their deleterious effects. Using primary lung lymphatic endothelial cells (L-LECs), we examined how cocaine and HIV-1 gp120, alone and together, modulate signaling and functional properties of L-LECs. We found that brief cocaine exposure activated paxillin and induced cytoskeletal rearrangement, while sustained exposure increased fibronectin (FN) expression, decreased Robo4 expression, and enhanced the permeability of L-LEC monolayers. Moreover, incubating L-LECs with both cocaine and HIV-1 gp120 exacerbated hyperpermeability, significantly enhanced apoptosis, and further impaired in vitro wound healing as compared with cocaine alone. Our studies also suggested that the sigma-1 receptor (Sigma-1R) and the dopamine-4 receptor (D4R) are involved in cocaine-induced pathology in L-LECs. Seeking clinical correlation, we found that FN levels in sera and lung tissue of HIV(+) donors were significantly elevated as compared to HIV(-) donors. Our in vitro data demonstrate that cocaine and HIV-1 gp120 induce dysfunction and damage of lung lymphatics, and suggest that cocaine use may exacerbate pulmonary edema and fibrosis associated with HIV infection. Continued exploration of the interplay between cocaine and HIV should assist the design of therapeutics to ameliorate HIV-induced pulmonary disorders within the drug using population. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  11. IL-10-secreting T cells from HIV-infected pregnant women downregulate HIV-1 replication: effect enhanced by antiretroviral treatment.

    Science.gov (United States)

    Bento, Cleonice A M; Hygino, Joana; Andrade, Regis M; Saramago, Carmen S M; Silva, Renato G; Silva, Agostinho A L; Linhares, Ulisses C; Brindeiro, Rodrigo; Tanuri, Amilcar; Rosenzwajg, Michelle; Klatzmann, David; Andrade, Arnaldo F B

    2009-01-02

    This study aimed to evaluate the impact of pregnancy-related immune events on the HIV-1 replication and to analyze their relationship with the risk of vertical transmission. The peripheral blood from HIV-1-infected pregnant women who controlled (G1) or not controlled (G2) their plasma viral load was drawn, and the plasma and the T cells were obtained. The T-cell cultures were activated in vitro with anti-CD3 and anti-CD28, and the proliferation and cytokine production profile were evaluated after 3 days of incubation. The in-vitro HIV-1 replication was measured in culture supernatants in the seventh day following stimulation. The cytokines were also analyzed in the plasma. Our results demonstrated a lower T-cell proliferation and a lower interleukin-1beta, tumor necrosis factor-alpha and interferon-gamma production in polyclonally activated T-cell cultures from G1 patients, when compared with G2. Furthermore, high levels of interleukin-10 were produced both systemically and by activated T-cell cultures from G1 patients. Interestingly, the neutralization of endogenous interleukin-10 by anti-interleukin-10 monoclonal antibody elevated both the inflammatory cytokines' release and the HIV-1 replication in the polyclonally activated T-cell cultures from G1 patients. Additionally, the maternal antiretroviral treatment significantly enhanced the systemic interleukin-10 production. Finally, the higher systemic interleukin-10 levels were inversely correlated with vertical virus transmission risk. These results indicate that a high tendency of pregnant women to produce interleukin-10 can help them control the HIV-1 replication, and this can reduce the risk of vertical transmission. Furthermore, our data suggest a role for maternal antiretroviral treatment in enhancing this phenomenon.

  12. Evolution of HIV Training for Enhanced Care Provision in Kenya ...

    African Journals Online (AJOL)

    Data sources: Various Government of Kenya publications, policy documents and websites on training for HIV service delivery. Publications and websites of stakeholders, donors and partners as well. Journal articles, published peer reviewed literature, abstracts, websites and programme reports related to training for HIV ...

  13. evolution of hiv training for enhanced care provision in kenya

    African Journals Online (AJOL)

    Objective: To provide an overview of the evolution of HIV training in Kenya, from. 2003 to date ... demand for the development of human resource base to respond to the evolving ... AIDS management despite the causative virus of. AIDS having ...

  14. Morphine enhances HIV-1SF162-mediated neuron death and delays recovery of injured neurites.

    Science.gov (United States)

    Masvekar, Ruturaj R; El-Hage, Nazira; Hauser, Kurt F; Knapp, Pamela E

    2014-01-01

    HIV-1 enters the CNS soon after initial systemic infection; within the CNS parenchyma infected and/or activated perivascular macrophages, microglia and astrocytes release viral and cellular toxins that drive secondary toxicity in neurons and other cell types. Our previous work has largely modeled HIV-neuropathology using the individual viral proteins Tat or gp120, with murine striatal neurons as targets. To model disease processes more closely, the current study uses supernatant from HIV-1-infected cells. Supernatant from HIV-1SF162-infected differentiated-U937 cells (HIV+sup) was collected and p24 level was measured by ELISA to assess the infection. Injection drug abuse is a significant risk factor for HIV-infection, and opiate drug abusers show increased HIV-neuropathology, even with anti-retroviral treatments. We therefore assessed HIV+sup effects on neuronal survival and neurite growth/pruning with or without concurrent exposure to morphine, an opiate that preferentially acts through µ-opioid receptors. Effects of HIV+sup ± morphine were assessed on neuronal populations, and also by time-lapse imaging of individual cells. HIV+sup caused dose-dependent toxicity over a range of p24 levels (10-500 pg/ml). Significant interactions occurred with morphine at lower p24 levels (10 and 25 pg/ml), and GSK3β was implicated as a point of convergence. In the presence of glia, selective neurotoxic measures were significantly enhanced and interactions with morphine were also augmented, perhaps related to a decreased level of BDNF. Importantly, the arrest of neurite growth that occurred with exposure to HIV+sup was reversible unless neurons were continuously exposed to morphine. Thus, while reducing HIV-infection levels may be protective, ongoing exposure to opiates may limit recovery. Opiate interactions observed in this HIV-infective environment were similar, though not entirely concordant, with Tat/gp120 interactions reported previously, suggesting unique interactions

  15. Morphine enhances HIV-1SF162-mediated neuron death and delays recovery of injured neurites.

    Directory of Open Access Journals (Sweden)

    Ruturaj R Masvekar

    Full Text Available HIV-1 enters the CNS soon after initial systemic infection; within the CNS parenchyma infected and/or activated perivascular macrophages, microglia and astrocytes release viral and cellular toxins that drive secondary toxicity in neurons and other cell types. Our previous work has largely modeled HIV-neuropathology using the individual viral proteins Tat or gp120, with murine striatal neurons as targets. To model disease processes more closely, the current study uses supernatant from HIV-1-infected cells. Supernatant from HIV-1SF162-infected differentiated-U937 cells (HIV+sup was collected and p24 level was measured by ELISA to assess the infection. Injection drug abuse is a significant risk factor for HIV-infection, and opiate drug abusers show increased HIV-neuropathology, even with anti-retroviral treatments. We therefore assessed HIV+sup effects on neuronal survival and neurite growth/pruning with or without concurrent exposure to morphine, an opiate that preferentially acts through µ-opioid receptors. Effects of HIV+sup ± morphine were assessed on neuronal populations, and also by time-lapse imaging of individual cells. HIV+sup caused dose-dependent toxicity over a range of p24 levels (10-500 pg/ml. Significant interactions occurred with morphine at lower p24 levels (10 and 25 pg/ml, and GSK3β was implicated as a point of convergence. In the presence of glia, selective neurotoxic measures were significantly enhanced and interactions with morphine were also augmented, perhaps related to a decreased level of BDNF. Importantly, the arrest of neurite growth that occurred with exposure to HIV+sup was reversible unless neurons were continuously exposed to morphine. Thus, while reducing HIV-infection levels may be protective, ongoing exposure to opiates may limit recovery. Opiate interactions observed in this HIV-infective environment were similar, though not entirely concordant, with Tat/gp120 interactions reported previously, suggesting

  16. Sialoadhesin expressed on IFN-induced monocytes binds HIV-1 and enhances infectivity.

    Directory of Open Access Journals (Sweden)

    Hans Rempel

    Full Text Available BACKGROUND: HIV-1 infection dysregulates the immune system and alters gene expression in circulating monocytes. Differential gene expression analysis of CD14(+ monocytes from subjects infected with HIV-1 revealed increased expression of sialoadhesin (Sn, CD169, Siglec 1, a cell adhesion molecule first described in a subset of macrophages activated in chronic inflammatory diseases. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed sialoadhesin expression on CD14(+ monocytes by flow cytometry and found significantly higher expression in subjects with elevated viral loads compared to subjects with undetectable viral loads. In cultured CD14(+ monocytes isolated from healthy individuals, sialoadhesin expression was induced by interferon-alpha and interferon-gamma but not tumor necrosis factor-alpha. Using a stringent binding assay, sialoadhesin-expressing monocytes adsorbed HIV-1 through interaction with the sialic acid residues on the viral envelope glycoprotein gp120. Furthermore, monocytes expressing sialoadhesin facilitated HIV-1 trans infection of permissive cells, which occurred in the absence of monocyte self-infection. CONCLUSIONS/SIGNIFICANCE: Increased sialoadhesin expression on CD14(+ monocytes occurred in response to HIV-1 infection with maximum expression associated with high viral load. We show that interferons induce sialoadhesin in primary CD14(+ monocytes, which is consistent with an antiviral response during viremia. Our findings suggest that circulating sialoadhesin-expressing monocytes are capable of binding HIV-1 and effectively delivering virus to target cells thereby enhancing the distribution of HIV-1. Sialoadhesin could disseminate HIV-1 to viral reservoirs during monocyte immunosurveillance or migration to sites of inflammation and then facilitate HIV-1 infection of permissive cells.

  17. λ Light Chain Bias Associated With Enhanced Binding and Function of Anti-HIV Env Glycoprotein Antibodies.

    Science.gov (United States)

    Sajadi, Mohammad M; Farshidpour, Maham; Brown, Eric P; Ouyang, Xin; Seaman, Michael S; Pazgier, Marzena; Ackerman, Margaret E; Robinson, Harriet; Tomaras, Georgia; Parsons, Matthew S; Charurat, Manhattan; DeVico, Anthony L; Redfield, Robert R; Lewis, George K

    2016-01-01

    The humoral response to human immunodeficiency virus (HIV) remains incompletely understood. In this report, we describe biased λ light chain use during the HIV Env glycoprotein (Env) response in HIV infection and vaccination. We examined HIV Env binding (and neutralization) in the context of light chain use in subjects with acute HIV infection, chronic HIV infection, and among HIV vaccinees. In all populations tested, there was a λ chain bias for HIV Env binding antibodies, compared with other HIV antigens (such as p24) or tetanus toxoid. In subjects with chronic HIV infection, a λ bias was noted for neutralization, with λ antibodies accounting for up to 90% of all neutralization activity observed. This is the first report of antibody function in a human infection being tied to light chain use. In HIV infection, antibodies expressing λ light chains tended to have longer CDRL3s, increased light chain contact with HIV Env, and less hypermutation in the heavy chain, compared with antibodies using the κ light chain. These data also support an evolutionary model for the understanding the various κ to λ light chain ratios observed across species and suggest that the λ light chain bias against HIV provides the host an advantage in developing a more efficient humoral response. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  18. Biocompatible polymer enhances the in vitro and in vivo transfection efficiency of HVJ envelope vector.

    Science.gov (United States)

    Mima, Hidetoshi; Tomoshige, Ryuji; Kanamori, Toshihide; Tabata, Yasuhiko; Yamamoto, Seiji; Ito, Susumu; Tamai, Katsuto; Kaneda, Yasufumi

    2005-07-01

    Vector development is critical for the advancement of human gene therapy. However, the use of viral vectors raises many safety concerns and most non-viral methods are less efficient for gene transfer. One of the breakthroughs in vector technology is the combination of the vector with various polymers. HVJ (hemagglutinating virus of Japan) envelope vector (HVJ-E) has been developed as a versatile gene transfer vector. In this study, we combined HVJ-E with cationized gelatin to make it a more powerful tool and assessed its transfection efficiency in vitro and in vivo. In addition, we investigated the mechanism of the gene transfer by means of the inhibition of fusion or endocytosis. The combination of both protamine sulfate and cationized gelatin with HVJ-E, referred to as PS-CG-HVJ-E, further enhanced the in vitro transfection efficiency. In CT26 cells, the luciferase gene expression of PS-CG-HVJ-E was approximately 10 times higher than that of the combination of protamine sulfate with HVJ-E or the combination of cationized gelatin with HVJ-E, referred to as PS-HVJ-E or CG-HVJ-E, respectively. Furthermore, the luciferase gene expression in liver mediated by intravenous administration of CG-HVJ-E was much higher than the luciferase gene expression mediated by PS-HVJ-E or PS-CG-HVJ-E and approximately 100 times higher than that mediated by HVJ-E alone. Cationized gelatin-conjugated HVJ-E enhanced gene transfection efficiency both in vitro and in vivo. These results suggest that low molecular weight cationized gelatin may be appropriate for complex formation with various envelope viruses, such as retrovirus, herpes virus and HIV. Copyright 2005 John Wiley & Sons, Ltd.

  19. HIV-1 gp41-targeting fusion inhibitory peptides enhance the gp120-targeting protein-mediated inactivation of HIV-1 virions.

    Science.gov (United States)

    Qi, Qianqian; Wang, Qian; Chen, Weizao; Du, Lanying; Dimitrov, Dimiter S; Lu, Lu; Jiang, Shibo

    2017-06-21

    Protein- or peptide-based viral inactivators are being developed as novel antiviral drugs with improved efficacy, pharmacokinetics and toxicity profiles because they actively inactivate cell-free human immunodeficiency virus type 1 (HIV-1) virions before attachment to host cells. By contrast, most clinically used antiviral drugs must penetrate host cells to inhibit viral replication. In this study, we pre-treated HIV-1 particles with a gp120-targeting bispecific multivalent protein, 2Dm2m or 4Dm2m, in the presence or absence of the gp41-targeting HIV-1 fusion inhibitory peptides enfuvirtide (T20), T2635, or sifuvirtide (SFT). HIV-1 virions were separated from the inhibitors using PEG-6000, followed by testing of the residual infectivity of the HIV-1 virions. 2Dm2m and 4Dm2m exhibited significant inactivation activity against all HIV-1 strains tested with EC50 values at the low nanomolar level, whereas none of the gp41-targeting peptides showed inactivation activity at concentrations up to 250 nM. Notably, these three peptides significantly enhanced protein-mediated inactivation against cell-free HIV-1 virions, including HIV-1 laboratory-adapted and primary HIV-1 strains, as well as those resistant to T20 or T2635 and virions released from reactivated latently HIV-1-infected cells. These results indicate that the gp120-targeting bispecific multivalent proteins 2Dm2m and 4Dm2m have potential for further development as HIV-1 inactivator-based antiviral drugs for use in the clinic, either alone or in combination with a gp41-targeting HIV-1 fusion inhibitor such as T20, to treat patients with HIV-1 infection and AIDS.

  20. The use of erection enhancing medication and party drugs among men living with HIV in Europe.

    Science.gov (United States)

    De Ryck, Iris; Van Laeken, David; Noestlinger, Christiana; Platteau, Tom; Colebunders, Robert

    2013-08-01

    Studies have shown more erectile dysfunction (ED) in men living with HIV (MLHIV), relative to age matched HIV-negative men. Erection enhancing medication (EEM) is more frequently used by HIV-positive men than in the general male population. Increased sexually transmitted infection has been described in HIV-positive men with ED using EEM. This study investigated the use of EEM and party drugs (methyleendioxymethamfetamine (XTC), gammahydroxybutyrate (GHB) "fluid XTC" and alkyl nitrites "poppers") among MLHIV. Self-administered questionnaires were distributed consecutively to all patients attending 17 European HIV treatment centers. The sample included 1118 HIV-positive men, among whom 74.5% men having sex with men (MSM). The use of EEM was more frequent in MSM than in heterosexual men (odds ratio (OR) 3.33, pparty drugs (OR 2.30, p=0.01). Physicians taking care of MLHIV need to be aware of the high prevalence of (nonmedical) use of EEM and party drugs. Medical provision of EEM should be combined with a discussion on safer sex behavior and the risk related to concomitant use of party drugs and illegal EEM.

  1. Intracellular spectral recompositioning of light enhances algal photosynthetic efficiency.

    Science.gov (United States)

    Fu, Weiqi; Chaiboonchoe, Amphun; Khraiwesh, Basel; Sultana, Mehar; Jaiswal, Ashish; Jijakli, Kenan; Nelson, David R; Al-Hrout, Ala'a; Baig, Badriya; Amin, Amr; Salehi-Ashtiani, Kourosh

    2017-09-01

    Diatoms, considered as one of the most diverse and largest groups of algae, can provide the means to reach a sustainable production of petrochemical substitutes and bioactive compounds. However, a prerequisite to achieving this goal is to increase the solar-to-biomass conversion efficiency of photosynthesis, which generally remains less than 5% for most photosynthetic organisms. We have developed and implemented a rapid and effective approach, herein referred to as intracellular spectral recompositioning (ISR) of light, which, through absorption of excess blue light and its intracellular emission in the green spectral band, can improve light utilization. We demonstrate that ISR can be used chemogenically, by using lipophilic fluorophores, or biogenically, through the expression of an enhanced green fluorescent protein (eGFP) in the model diatom Phaeodactylum tricornutum. Engineered P. tricornutum cells expressing eGFP achieved 28% higher efficiency in photosynthesis than the parental strain, along with an increased effective quantum yield and reduced nonphotochemical quenching (NPQ) induction levels under high-light conditions. Further, pond simulator experiments demonstrated that eGFP transformants could outperform their wild-type parental strain by 50% in biomass production rate under simulated outdoor sunlight conditions. Transcriptome analysis identified up-regulation of major photosynthesis genes in the engineered strain in comparison with the wild type, along with down-regulation of NPQ genes involved in light stress response. Our findings provide a proof of concept for a strategy of developing more efficient photosynthetic cell factories to produce algae-based biofuels and bioactive products.

  2. Enhancing wind turbines efficiency with passive reconfiguration of flexible blades

    Science.gov (United States)

    Cognet, Vincent P. A.; Thiria, Benjamin; Courrech Du Pont, Sylvain; MSC Team; PMMH Team

    2015-11-01

    Nature provides excellent examples where flexible materials are advantageous in a fluid stream. By folding, leaves decrease the drag caused by air stream; and birds' flapping is much more efficient with flexible wings. Motivated by this, we investigate the effect of flexible blades on the performance of a wind turbine. The effect of chordwise flexible blades is studied both experimentally and theoretically on a small wind turbine in steady state. Four parameters are varied: the wind velocity, the resisting torque, the pitch angle, and the blade's bending modulus. We find an optimum efficiency with respect to the bending modulus. By tuning our four parameters, the wind turbine with flexible blades has a high-efficiency range significantly larger than rigid blades', and, furthermore enhances the operating range. These results are all the more important as one of the current issues concerning wind turbines is the enlargement of their operating range. To explain these results, we propose a simple two-dimensional model by discretising the blade along the radius. We take into account the variation of drag and lift coefficients with the bending ability. This model matches experimental observations and demonstrates the contribution of the reconfiguration of the blade. Matiere et Systemes Complexes.

  3. High performance metamaterial device with enhanced electromagnetic energy harvesting efficiency

    Science.gov (United States)

    Shang, Shuai; Yang, Shizhong; Shan, Meng; Liu, Jing; Cao, Hailin

    2017-10-01

    A high performance metamaterial device for electromagnetic energy harvesting is presented. The unit cell of the metamaterial device consists of four identical omega ring resonators arranged in rotational symmetry, and each omega ring is loaded with a 50 Ω resistor that mimics the input impedance of a rectifier circuit. A proof-of-concept prototype is designed for operation at the frequency of 5.8 GHz. Here, the efficient energy harvesting is validated by the energy dissipated in each resistor. Based on the full absorption concept, the metamaterial device achieves a harvesting efficiency up to 93.1% under normal incidence. In addition, the energy harvester shows polarization independent and wide-angle incident frequency responses with good harvesting characteristics over the entire operating range. The surface current distribution is analyzed to gain an insight into the energy harvesting mechanism. Moreover, the harvester prototype is manufactured and measured, and the simulated and measured results are in good agreement. Due to the enhanced electromagnetic energy harvesting efficiency, the proposed device is a good candidate for microwave power transmission.

  4. Enhancement of HIV-1 infection and intestinal CD4+ T cell depletion ex vivo by gut microbes altered during chronic HIV-1 infection.

    Science.gov (United States)

    Dillon, Stephanie M; Lee, Eric J; Donovan, Andrew M; Guo, Kejun; Harper, Michael S; Frank, Daniel N; McCarter, Martin D; Santiago, Mario L; Wilson, Cara C

    2016-01-14

    Early HIV-1 infection is characterized by high levels of HIV-1 replication and substantial CD4 T cell depletion in the intestinal mucosa, intestinal epithelial barrier breakdown, and microbial translocation. HIV-1-induced disruption of intestinal homeostasis has also been associated with changes in the intestinal microbiome that are linked to mucosal and systemic immune activation. In this study, we investigated the impact of representative bacterial species that were altered in the colonic mucosa of viremic HIV-1 infected individuals (HIV-altered mucosal bacteria; HAMB) on intestinal CD4 T cell function, infection by HIV-1, and survival in vitro. Lamina propria (LP) mononuclear cells were infected with CCR5-tropic HIV-1BaL or mock infected, exposed to high (3 gram-negative) or low (2 gram-positive) abundance HAMB or control gram-negative Escherichia coli and levels of productive HIV-1 infection and CD4 T cell depletion assessed. HAMB-associated changes in LP CD4 T cell activation, proliferation and HIV-1 co-receptor expression were also evaluated. The majority of HAMB increased HIV-1 infection and depletion of LP CD4 T cells, but gram-negative HAMB enhanced CD4 T cell infection to a greater degree than gram-positive HAMB. Most gram-negative HAMB enhanced T cell infection to levels similar to that induced by gram-negative E. coli despite lower induction of T cell activation and proliferation by HAMB. Both gram-negative HAMB and E. coli significantly increased expression of HIV-1 co-receptor CCR5 on LP CD4 T cells. Lipopolysaccharide, a gram-negative bacteria cell wall component, up-regulated CCR5 expression on LP CD4 T cells whereas gram-positive cell wall lipoteichoic acid did not. Upregulation of CCR5 by gram-negative HAMB was largely abrogated in CD4 T cell-enriched cultures suggesting an indirect mode of stimulation. Gram-negative commensal bacteria that are altered in abundance in the colonic mucosa of HIV-1 infected individuals have the capacity to enhance

  5. Assessing cost and technical efficiency of HIV prevention interventions in sub-Saharan Africa: the ORPHEA study design and methods.

    Science.gov (United States)

    Bautista-Arredondo, Sergio; Sosa-Rubí, Sandra G; Opuni, Marjorie; Kwan, Ada; Chaumont, Claire; Coetzee, Jenny; Condo, Jeanine; Dzekedzeke, Kumbutso; Galárraga, Omar; Martinson, Neil; Masiye, Felix; Nsanzimana, Sabin; Wamai, Richard; Wang'ombe, Joseph

    2014-11-29

    Scaling up services to achieve HIV targets will require that countries optimize the use of available funding. Robust unit cost estimates are essential for the better use of resources, and information on the heterogeneity in the unit cost of delivering HIV services across facilities - both within and across countries - is critical to identifying and addressing inefficiencies. There is limited information on the unit cost of HIV prevention services in sub-Saharan Africa and information on the heterogeneity within and across countries and determinants of this variation is even more scarce. The "Optimizing the Response in Prevention: HIV Efficiency in Africa" (ORPHEA) study aims to add to the empirical body of knowledge on the cost and technical efficiency of HIV prevention services that decision makers can use to inform policy and planning. ORPHEA is a cross-sectional observational study conducted in 304 service delivery sites in Kenya, Rwanda, South Africa, and Zambia to assess the cost, cost structure, cost variability, and the determinants of efficiency for four HIV interventions: HIV testing and counselling (HTC), prevention of mother-to-child transmission (PMTCT), voluntary medical male circumcision (VMMC), and HIV prevention for sex workers. ORPHEA collected information at three levels (district, facility, and individual) on inputs to HIV prevention service production and their prices, outputs produced along the cascade of services, facility-level characteristics and contextual factors, district-level factors likely to influence the performance of facilities as well as the demand for HIV prevention services, and information on process quality for HTC, PMTCT, and VMMC services. ORPHEA is one of the most comprehensive studies on the cost and technical efficiency of HIV prevention interventions to date. The study applied a robust methodological design to collect comparable information to estimate the cost of HTC, PMTCT, VMMC, and sex worker prevention services in

  6. Use of expenditure analysis to enhance returns on investments in HIV services.

    Science.gov (United States)

    Honermann, Brian; O'Hagan, Richael

    2017-09-01

    Globally, the response to the HIV epidemic is at a crisis point. International investments in the HIV response have been essentially flat for 8 years and domestic budgets in low and middle-income countries - still recovering from the global recession - have not been able to fill the resource gap to drive a full-fledged HIV response. Still, efficiencies and prioritization of evidence-based interventions enable a significant scale-up of treatment, but millions more people remain without treatment. This review looks at recent data and research to evaluate interventions that may help close gaps in service provision that undermine testing and treatment programs. The President's Emergency Plan for AIDS Relief recently began publicly releasing vast programmatic and expenditure data. These data reveal potential efficiency gaps in testing and treatment programs, particularly in the area of linkage and retention. Interventions such as HIV self-testing have been proposed to help, but whether they can deliver better results remains unclear. Same-day initiation on treatment improves initiation, retention, and viral suppression rates. Near real-time analysis of data and active response is critical in improving efficiencies in programs. More investment in implementation research is necessary to improve linkage to care and treatment to reach 90-90-90 goals.

  7. Efficient Biologically Inspired Photocell Enhanced by Delocalized Quantum States

    Science.gov (United States)

    Creatore, C.; Parker, M. A.; Emmott, S.; Chin, A. W.

    2013-12-01

    Artificially implementing the biological light reactions responsible for the remarkably efficient photon-to-charge conversion in photosynthetic complexes represents a new direction for the future development of photovoltaic devices. Here, we develop such a paradigm and present a model photocell based on the nanoscale architecture and molecular elements of photosynthetic reaction centers. Quantum interference of photon absorption and emission induced by the dipole-dipole interaction between molecular excited states guarantees an enhanced light-to-current conversion and power generation for a wide range of electronic, thermal, and optical parameters for optimized dipolar geometries. This result opens a promising new route for designing artificial light-harvesting devices inspired by biological photosynthesis and quantum technologies.

  8. Enhanced efficiency for propagation of anthurium by tissue culture technique

    Directory of Open Access Journals (Sweden)

    Te-chato, S.

    2005-09-01

    Full Text Available Enhanced efficiency for clonal propagation of anthurium could be carried out by increasing the concentration of adenine sulfate and overlaying liquid medium on solid medium. The results revealed that increasing concentration of adenine sulfate form 0.1 to 1 mg/l yielded an average number of shoot of 21 per explant. Addition of half strength liquid MS medium without phytohormone to the old cultures (agar solidified medium gave optimum results in growth, healthy stem and leaves. In case of gelling agent, gelrite yielded a high number of shoots without callus formation. Proliferation rate of the shoots in gelrite solidified medium in the following subculture was not found. Thus, agar-agar was suitable for propagation in terms of low cost production and proliferation rate.

  9. Dental ergonomics: Basic steps to enhance work efficiency

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    Abdul Rahim Shaik

    2015-01-01

    Full Text Available The nature of the dental profession and the postures assumed by the dental surgeons during their professional work has a huge impact on the dental surgeon′s body and carries with it a high risk of musculoskeletal disorders (MSDs. To perform efficiently and effectively, they shall always like to attain a position that allows them to achieve optimum access, visibility, comfort, and control at all times. Good ergonomic design of the workplace is a basic requirement for facilitating the balanced musculoskeletal health that will enable longer, healthier career, enhance productivity, and minimize MSDs among dental surgeons. While treating the patients, they are concerned about patients′ comfort and pay little attention to their own health till they begin to experience discomfort in their body. With a little attention and creativity, dental surgeons can improve their comfort on the job during the course of their career.

  10. Crystal Structure of NFAT Bound to the HIV-1 LTR Tandem κB Enhancer Element

    Energy Technology Data Exchange (ETDEWEB)

    Bates, Darren L.; Barthel, Kristen K.B.; Wu, Yongqing; Kalhor, Reza; Stroud, James C.; Giffin, Michael J.; Chen, Lin (UCLA); (Colorado)

    2008-05-27

    Here, we have determined the crystal structure of the DNA binding domain of NFAT bound to the HIV-1 long terminal repeat (LTR) tandem {kappa}B enhancer element of 3.05 {angstrom} resolution. NFAT binds as a dimer to the upstream {kappa}B site (Core II), but as a monomer to the 3' end of the downstream {kappa}B site (Core I). The DNA shows a significant bend near the 5' end of Core I, where a lysine residue from NFAT bound to the 3' end of Core II inserts into the minor groove and seems to cause DNA bases to flip out. Consistent with this structural feature, the 5' end of Core I become hypersensitive to dimethylsulfate in the in vivo footprinting upon transcriptional activation of the HIV-1 LTR. Our studies provide a basis for futher investigating the functional mechanism of NFAT in HIV-1 transcription and replication.

  11. A Peptide Derived from the HIV-1 gp120 Coreceptor-Binding Region Promotes Formation of PAP248-286 Amyloid Fibrils to Enhance HIV-1 Infection.

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    Jinquan Chen

    Full Text Available Semen is a major vehicle for HIV transmission. Prostatic acid phosphatase (PAP fragments, such as PAP248-286, in human semen can form amyloid fibrils to enhance HIV infection. Other endogenous or exogenous factors present during sexual intercourse have also been reported to promote the formation of seminal amyloid fibrils.Here, we demonstrated that a synthetic 15-residue peptide derived from the HIV-1 gp120 coreceptor-binding region, designated enhancing peptide 2 (EP2, can rapidly self-assemble into nanofibers. These EP2-derivated nanofibers promptly accelerated the formation of semen amyloid fibrils by PAP248-286, as shown by Thioflavin T (ThT and Congo red assays. The amyloid fibrils presented similar morphology, assessed via transmission electron microscopy (TEM, in the presence or absence of EP2. Circular dichroism (CD spectroscopy revealed that EP2 accelerates PAP248-286 amyloid fibril formation by promoting the structural transition of PAP248-286 from a random coil into a cross-β-sheet. Newly formed semen amyloid fibrils effectively enhanced HIV-1 infection in TZM-bl cells and U87 cells by promoting the binding of HIV-1 virions to target cells.Nanofibers composed of EP2 promote the formation of PAP248-286 amyloid fibrils and enhance HIV-1 infection.

  12. Cognitive Training Enhances Auditory Attention Efficiency in Older Adults

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    Jennifer L. O’Brien

    2017-10-01

    Full Text Available Auditory cognitive training (ACT improves attention in older adults; however, the underlying neurophysiological mechanisms are still unknown. The present study examined the effects of ACT on the P3b event-related potential reflecting attention allocation (amplitude and speed of processing (latency during stimulus categorization and the P1-N1-P2 complex reflecting perceptual processing (amplitude and latency. Participants completed an auditory oddball task before and after 10 weeks of ACT (n = 9 or a no contact control period (n = 15. Parietal P3b amplitudes to oddball stimuli decreased at post-test in the trained group as compared to those in the control group, and frontal P3b amplitudes show a similar trend, potentially reflecting more efficient attentional allocation after ACT. No advantages for the ACT group were evident for auditory perceptual processing or speed of processing in this small sample. Our results provide preliminary evidence that ACT may enhance the efficiency of attention allocation, which may account for the positive impact of ACT on the everyday functioning of older adults.

  13. Cognitive Training Enhances Auditory Attention Efficiency in Older Adults.

    Science.gov (United States)

    O'Brien, Jennifer L; Lister, Jennifer J; Fausto, Bernadette A; Clifton, Gregory K; Edwards, Jerri D

    2017-01-01

    Auditory cognitive training (ACT) improves attention in older adults; however, the underlying neurophysiological mechanisms are still unknown. The present study examined the effects of ACT on the P3b event-related potential reflecting attention allocation (amplitude) and speed of processing (latency) during stimulus categorization and the P1-N1-P2 complex reflecting perceptual processing (amplitude and latency). Participants completed an auditory oddball task before and after 10 weeks of ACT (n = 9) or a no contact control period (n = 15). Parietal P3b amplitudes to oddball stimuli decreased at post-test in the trained group as compared to those in the control group, and frontal P3b amplitudes show a similar trend, potentially reflecting more efficient attentional allocation after ACT. No advantages for the ACT group were evident for auditory perceptual processing or speed of processing in this small sample. Our results provide preliminary evidence that ACT may enhance the efficiency of attention allocation, which may account for the positive impact of ACT on the everyday functioning of older adults.

  14. Efficient Enhancement for Spatial Scalable Video Coding Transmission

    Directory of Open Access Journals (Sweden)

    Mayada Khairy

    2017-01-01

    Full Text Available Scalable Video Coding (SVC is an international standard technique for video compression. It is an extension of H.264 Advanced Video Coding (AVC. In the encoding of video streams by SVC, it is suitable to employ the macroblock (MB mode because it affords superior coding efficiency. However, the exhaustive mode decision technique that is usually used for SVC increases the computational complexity, resulting in a longer encoding time (ET. Many other algorithms were proposed to solve this problem with imperfection of increasing transmission time (TT across the network. To minimize the ET and TT, this paper introduces four efficient algorithms based on spatial scalability. The algorithms utilize the mode-distribution correlation between the base layer (BL and enhancement layers (ELs and interpolation between the EL frames. The proposed algorithms are of two categories. Those of the first category are based on interlayer residual SVC spatial scalability. They employ two methods, namely, interlayer interpolation (ILIP and the interlayer base mode (ILBM method, and enable ET and TT savings of up to 69.3% and 83.6%, respectively. The algorithms of the second category are based on full-search SVC spatial scalability. They utilize two methods, namely, full interpolation (FIP and the full-base mode (FBM method, and enable ET and TT savings of up to 55.3% and 76.6%, respectively.

  15. P. falciparum enhances HIV replication in an experimental malaria challenge system.

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    Marika Orlov

    Full Text Available Co-infection with HIV and P. falciparum worsens the prognosis of both infections; however, the mechanisms driving this adverse interaction are not fully delineated. To evaluate this, we studied HIV-1 and P. falciparum interactions in vitro using peripheral blood mononuclear cells (PBMCs from human malaria naïve volunteers experimentally infected with P. falciparum in a malaria challenge trial. PBMCs collected before the malaria challenge and at several time points post-infection were infected with HIV-1 and co-cultured with either P. falciparum infected (iRBCs or uninfected (uRBCs red blood cells. HIV p24Ag and TNF-α, IFN-γ, IL-4, IL-6, IL-10, IL-17, and MIP-1α were quantified in the co-culture supernatants. In general, iRBCs stimulated more HIV p24Ag production by PBMCs than did uRBCs. HIV p24Ag production by PBMCs in the presence of iRBCs (but not uRBCs further increased during convalescence (days 35, 56, and 90 post-challenge. In parallel, iRBCs induced higher secretion of pro-inflammatory cytokines (TNF-α, IFN-γ, and MIP-1α than uRBCs, and production increased further during convalescence. Because the increase in p24Ag production occurred after parasitemia and generalized immune activation had resolved, our results suggest that enhanced HIV production is related to the development of anti-malaria immunity and may be mediated by pro-inflammatory cytokines.

  16. Efficiency Enhancement of Silicon Solar Cells by Porous Silicon Technology

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    Eugenijus SHATKOVSKIS

    2012-09-01

    Full Text Available Silicon solar cells produced by a usual technology in p-type, crystalline silicon wafer were investigated. The manufactured solar cells were of total thickness 450 mm, the junction depth was of 0.5 mm – 0.7 mm. Porous silicon technologies were adapted to enhance cell efficiency. The production of porous silicon layer was carried out in HF: ethanol = 1 : 2 volume ratio electrolytes, illuminating by 50 W halogen lamps at the time of processing. The etching current was computer-controlled in the limits of (6 ÷ 14 mA/cm2, etching time was set in the interval of (10 ÷ 20 s. The characteristics and performance of the solar cells samples was carried out illuminating by Xenon 5000 K lamp light. Current-voltage characteristic studies have shown that porous silicon structures produced affect the extent of dark and lighting parameters of the samples. Exactly it affects current-voltage characteristic and serial resistance of the cells. It has shown, the formation of porous silicon structure causes an increase in the electric power created of solar cell. Conversion efficiency increases also respectively to the initial efficiency of cell. Increase of solar cell maximum power in 15 or even more percent is found. The highest increase in power have been observed in the spectral range of Dl @ (450 ÷ 850 nm, where ~ 60 % of the A1.5 spectra solar energy is located. It has been demonstrated that porous silicon technology is effective tool to improve the silicon solar cells performance.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2428

  17. Image enhancement for increased dot-counting efficiency in FISH.

    Science.gov (United States)

    Shah, Shishir

    2007-11-01

    The most commonly used molecular cytogenetic technique is fluorescence in situ hybridization (FISH). It has been widely applied in many areas of diagnosis and research, including pre-natal and post-natal screening of chromosomal aberrations, pre-implantation genetic diagnosis, cancer cytogenetics, gene mapping, molecular pathology and developmental molecular biology. The analysis of FISH images consists of detecting fluorescent dots, after which the number of dots per cell can be counted or their relative positions can be measured. A major impediment in the analysis of FISH specimens is signal (dot) quality, which is influenced by the hybridization efficiency and/or the sensitivity of the camera that records the images. In this paper, we present an approach to improve the efficiency of detecting fluorescent signals in FISH images by recovering the radiance map of the camera. This allows us to generate a high-dynamic-range image wherein an extended range of the sample radiance captured by the camera can be visualized at distinct intensity values. The resulting higher-order numeric complexity of the transformed image is adjusted (or simplified) by examining the intensity distribution in each of the three colour channels (red, green and blue), and remapping the intensity values to generate a high-contrast image with a lower-order (compressed) dynamic range. The remapping is based on a criterion that optimizes the detection of the hybridized signals, allowing attenuation of saturated intensity values while amplifying low-intensity signals. A simple dot-counting algorithm is used to automatically process 2000 FISH images. The images are taken for lymphocytes from cultured blood specimens for cytogenetic testing. Images are manually analyzed by an expert to obtain ground truth for dot counts. A quantitative analysis is performed by comparing results of automated dot detection on images before and after enhancement with the developed algorithms. In addition, common errors

  18. An improved protocol for efficient engraftment in NOD/LTSZ-SCIDIL-2Rγnull mice allows HIV replication and development of anti-HIV immune responses.

    Directory of Open Access Journals (Sweden)

    Maneesh Singh

    Full Text Available Cord blood hematopoietic progenitor cells (CB-HPCs transplanted immunodeficient NOD/LtsZ-scidIL2Rγ(null (NSG and NOD/SCID/IL2Rγ(null (NOG mice need efficient human cell engraftment for long-term HIV-1 replication studies. Total body irradiation (TBI is a classical myeloablation regimen used to improve engraftment levels of human cells in these humanized mice. Some recent reports suggest the use of busulfan as a myeloablation regimen to transplant HPCs in neonatal and adult NSG mice. In the present study, we further ameliorated the busulfan myeloablation regimen with fresh CB-CD34+cell transplantation in 3-4 week old NSG mice. In this CB-CD34+transplanted NSG mice engraftment efficiency of human CD45+cell is over 90% in peripheral blood. Optimal engraftment promoted early and increased CD3+T cell levels, with better lymphoid tissue development and prolonged human cell chimerism over 300 days. These humanized NSG mice have shown long-lasting viremia after HIV-1JRCSF and HIV-1Bal inoculation through intravenous and rectal routes. We also saw a gradual decline of the CD4+T cell count, widespread immune activation, up-regulation of inflammation marker and microbial translocation after HIV-1 infection. Humanized NSG mice reconstituted according to our new protocol produced, moderate cellular and humoral immune responses to HIV-1 postinfection. We believe that NSG mice reconstituted according to our easy to use protocol will provide a better in vivo model for HIV-1 replication and anti-HIV-1 therapy trials.

  19. Treatment for stable HIV patients in England: can we increase efficiency and improve patient care?

    Science.gov (United States)

    Adams, Elisabeth; Ogden, David; Ehrlich, Alice; Hay, Phillip

    2014-07-01

    To estimate the costs and potential efficiency gains of changing the frequency of clinic appointments and drug dispensing arrangements for stable HIV patients compared to the costs of hospital pharmacy dispensing and home delivery. We estimated the annual costs per patient (HIV clinic visits and either first-line treatment or a common second-line regimen, with some patients switching to a second-line regimen during the year). The cost of three-, four- and six-monthly clinic appointments and drug supply was estimated assuming hospital dispensing (incurring value-added tax) and home delivery. Three-monthly appointments and hospital drug dispensing (baseline) were compared to other strategies. The baseline was the most costly option (£10,587 if first-line treatment and no switch to second-line regimen). Moving to six-monthly appointments and home delivery yielded savings of £1883 per patient annually. Assuming patients start on different regimens and may switch to second-line therapies, six-monthly appointments and three-monthly home delivery of drugs is the least expensive option and could result in nearly £2000 savings per patient. This translates to annual cost reduction of about £8 million for the estimated 4000 eligible patients not currently on home delivery in London, England. Different appointment schedules and drug supply options should be considered for stable HIV patients based on efficiency gains. However, this should be assessed for individual patients to meet their needs, especially around adherence and patient support. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  20. Adenosine deaminase enhances the immunogenicity of human dendritic cells from healthy and HIV-infected individuals.

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    Víctor Casanova

    Full Text Available ADA is an enzyme implicated in purine metabolism, and is critical to ensure normal immune function. Its congenital deficit leads to severe combined immunodeficiency (SCID. ADA binding to adenosine receptors on dendritic cell surface enables T-cell costimulation through CD26 crosslinking, which enhances T-cell activation and proliferation. Despite a large body of work on the actions of the ecto-enzyme ADA on T-cell activation, questions arise on whether ADA can also modulate dendritic cell maturation. To this end we investigated the effects of ADA on human monocyte derived dendritic cell biology. Our results show that both the enzymatic and non-enzymatic activities of ADA are implicated in the enhancement of CD80, CD83, CD86, CD40 and CCR7 expression on immature dendritic cells from healthy and HIV-infected individuals. These ADA-mediated increases in CD83 and costimulatory molecule expression is concomitant to an enhanced IL-12, IL-6, TNF-α, CXCL8(IL-8, CCL3(MIP1-α, CCL4(MIP-1β and CCL5(RANTES cytokine/chemokine secretion both in healthy and HIV-infected individuals and to an altered apoptotic death in cells from HIV-infected individuals. Consistently, ADA-mediated actions on iDCs are able to enhance allogeneic CD4 and CD8-T-cell proliferation, globally yielding increased iDC immunogenicity. Taken together, these findings suggest that ADA would promote enhanced and correctly polarized T-cell responses in strategies targeting asymptomatic HIV-infected individuals.

  1. Late gadolinium enhancement and subclinical cardiac dysfunction on cardiac MRI in asymptomatic HIV-positive men

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    A Loy

    2012-11-01

    Full Text Available Background: HIV is associated with an increased risk of cardiovascular disease (CVD and related clinical events. While traditional risk factors play an important role in the pathology of cardiovascular disease, HIV infection and its sequelae of immune activation and inflammation may have significant effects on the myocardium before becoming clinically evident. Cardiac MRI (CMR can be used to detect the pattern of these subclinical changes. This will lead to a better understanding of risk factors contributing to cardiovascular disease prior to it becoming clinically significant in HIV-positive patients. Methods: Prospective cohort study of 127 asymptomatic HIV-positive men on ART compared to 35 matched controls. Baseline demographics, HIV parameters, 12-lead ECG, routine biochemistry, and traditional cardiovascular risk factors were recorded. Images were acquired on a 3T Achieva Philips MRI scanner with 5 channel phase array cardiac coil and weight-based IV gadolinium was given at 0.15 mmol/kg dose with post-contrast inversion recovery imaging after 10 minutes. Results: 6/127 (4.7% of asymptomatic HIV-positive men had late gadolinium enhancement (LGE on MRI verses 1/35 (2.9% in the control group. In 3/6 (50% of cases this was in a classical infarction pattern with subendocardial involvement. 3/6 (50% were consistent with prior myocarditis. There was no significant difference in mean LVEF (66.93% vs 65.18%, LVMI (60.05g/m2 vs 55.94g/m2 or posterolateral wall thickness (8.28 mm and 8.16 mm between cases and controls respectively. There was significantly more diastolic dysfunction, E:A ratio < 1, found in the HIV-positive group, 18% vs 7% of controls (p = 0.037. Framingham risk did not predict either of these outcomes. Conclusions: There is an increased incidence of LGE detected on CMR in this asymptomatic HIV-positive cohort. Two distinct pathological processes were identifed as causing these changes, myocardial infarction and myocarditis

  2. The effect of multispectral image fusion enhancement on human efficiency.

    Science.gov (United States)

    Bittner, Jennifer L; Schill, M Trent; Mohd-Zaid, Fairul; Blaha, Leslie M

    2017-01-01

    The visual system can be highly influenced by changes to visual presentation. Thus, numerous techniques have been developed to augment imagery in an attempt to improve human perception. The current paper examines the potential impact of one such enhancement, multispectral image fusion, where imagery captured in varying spectral bands (e.g., visible, thermal, night vision) is algorithmically combined to produce an output to strengthen visual perception. We employ ideal observer analysis over a series of experimental conditions to (1) establish a framework for testing the impact of image fusion over the varying aspects surrounding its implementation (e.g., stimulus content, task) and (2) examine the effectiveness of fusion on human information processing efficiency in a basic application. We used a set of rotated Landolt C images captured with a number of individual sensor cameras and combined across seven traditional fusion algorithms (e.g., Laplacian pyramid, principal component analysis, averaging) in a 1-of-8 orientation task. We found that, contrary to the idea of fused imagery always producing a greater impact on perception, single-band imagery can be just as influential. Additionally, efficiency data were shown to fluctuate based on sensor combination instead of fusion algorithm, suggesting the need for examining multiple factors to determine the success of image fusion. Our use of ideal observer analysis, a popular technique from the vision sciences, provides not only a standard for testing fusion in direct relation to the visual system but also allows for comparable examination of fusion across its associated problem space of application.

  3. Epidemiology of tuberculosis in a high HIV prevalence population provided with enhanced diagnosis of symptomatic disease.

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    Elizabeth L Corbett

    2007-01-01

    Full Text Available Directly observed treatment short course (DOTS, the global control strategy aimed at controlling tuberculosis (TB transmission through prompt diagnosis of symptomatic smear-positive disease, has failed to prevent rising tuberculosis incidence rates in Africa brought about by the HIV epidemic. However, rising incidence does not necessarily imply failure to control tuberculosis transmission, which is primarily driven by prevalent infectious disease. We investigated the epidemiology of prevalent and incident TB in a high HIV prevalence population provided with enhanced primary health care.Twenty-two businesses in Harare, Zimbabwe, were provided with free smear- and culture-based investigation of TB symptoms through occupational clinics. Anonymised HIV tests were requested from all employees. After 2 y of follow-up for incident TB, a culture-based survey for undiagnosed prevalent TB was conducted. A total of 6,440 of 7,478 eligible employees participated. HIV prevalence was 19%. For HIV-positive and -negative participants, the incidence of culture-positive tuberculosis was 25.3 and 1.3 per 1,000 person-years, respectively (adjusted incidence rate ratio = 18.8; 95% confidence interval [CI] = 10.3 to 34.5: population attributable fraction = 78%, and point prevalence after 2 y was 5.7 and 2.6 per 1,000 population (adjusted odds ratio = 1.7; 95% CI = 0.5 to 6.8: population attributable fraction = 14%. Most patients with prevalent culture-positive TB had subclinical disease when first detected.Strategies based on prompt investigation of TB symptoms, such as DOTS, may be an effective way of controlling prevalent TB in high HIV prevalence populations. This may translate into effective control of TB transmission despite high TB incidence rates and a period of subclinical infectiousness in some patients.

  4. Nonequilibrium Enhances Adaptation Efficiency of Stochastic Biochemical Systems.

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    Chen Jia

    Full Text Available Adaptation is a crucial biological function possessed by many sensory systems. Early work has shown that some influential equilibrium models can achieve accurate adaptation. However, recent studies indicate that there are close relationships between adaptation and nonequilibrium. In this paper, we provide an explanation of these two seemingly contradictory results based on Markov models with relatively simple networks. We show that as the nonequilibrium driving becomes stronger, the system under consideration will undergo a phase transition along a fixed direction: from non-adaptation to simple adaptation then to oscillatory adaptation, while the transition in the opposite direction is forbidden. This indicates that although adaptation may be observed in equilibrium systems, it tends to occur in systems far away from equilibrium. In addition, we find that nonequilibrium will improve the performance of adaptation by enhancing the adaptation efficiency. All these results provide a deeper insight into the connection between adaptation and nonequilibrium. Finally, we use a more complicated network model of bacterial chemotaxis to validate the main results of this paper.

  5. Adhesion and fusion efficiencies of human immunodeficiency virus type 1 (HIV-1) surface proteins

    Science.gov (United States)

    Dobrowsky, Terrence M.; Rabi, S. Alireza; Nedellec, Rebecca; Daniels, Brian R.; Mullins, James I.; Mosier, Donald E.; Siliciano, Robert F.; Wirtz, Denis

    2013-10-01

    In about half of patients infected with HIV-1 subtype B, viral populations shift from utilizing the transmembrane protein CCR5 to CXCR4, as well as or instead of CCR5, during late stage progression of the disease. How the relative adhesion efficiency and fusion competency of the viral Env proteins relate to infection during this transition is not well understood. Using a virus-cell fusion assay and live-cell single-molecule force spectroscopy, we compare the entry competency of viral clones to tensile strengths of the individual Env-receptor bonds of Env proteins obtained from a HIV-1 infected patient prior to and during coreceptor switching. The results suggest that the genetic determinants of viral entry were predominantly enriched in the C3, HR1 and CD regions rather than V3. Env proteins can better mediate entry into cells after coreceptor switch; this effective entry capacity does not correlate with the bond strengths between viral Env and cellular receptors.

  6. An Enhanced Emtricitabine-Loaded Long-Acting Nanoformulation for Prevention or Treatment of HIV Infection.

    Science.gov (United States)

    Mandal, Subhra; Belshan, Michael; Holec, Ashley; Zhou, You; Destache, Christopher J

    2017-01-01

    Among various FDA-approved combination antiretroviral drugs (cARVs), emtricitabine (FTC) has been a very effective nucleoside reverse transcriptase inhibitor. Thus far, FTC is the only deoxycytidine nucleoside analog. However, a major drawback of FTC is its large volume distribution (averaging 1.4 liters/kg) and short plasma half-life (8 to 10 h), necessitating a high daily dosage. Thus, we propose an innovative fabrication method of loading FTC in poly(lactic-co-glycolic acid) polymeric nanoparticles (FTC-NPs), potentially overcoming these drawbacks. Our nanoformulation demonstrated enhanced FTC loading (size of HIV-1 inhibition study demonstrated that FTC-NP treatment results in a 50% inhibitory concentration (IC 50 ) ∼43 times lower in TZM-bl cells (0.00043 μg/ml) and ∼3.7 times lower (0.009 μg/ml) in peripheral blood mononuclear cells (PBMCs) than with FTC solution (TZM-bl cells, 0.01861, and PBMCs, 0.033 μg/ml). Further, on primary PBMCs, FTC-NPs also illustrate an HIV-1 infection blocking efficacy comparable to that of FTC solution. All the above-described studies substantiate that FTC nanoformulation prolongs intracellular FTC concentration and inhibition of HIV infection. Therefore, FTC-NPs potentially could be a long-acting, stable formulation to ensure once-biweekly dosing to prevent or treat HIV infection. Copyright © 2016 American Society for Microbiology.

  7. Enhanced immunogenicity of an HIV-1 DNA vaccine delivered with electroporation via combined intramuscular and intradermal routes.

    Science.gov (United States)

    Mann, Jamie F S; McKay, Paul F; Fiserova, Anezka; Klein, Katja; Cope, Alethea; Rogers, Paul; Swales, Julie; Seaman, Michael S; Combadiere, Behazine; Shattock, Robin J

    2014-06-01

    It is accepted that an effective prophylactic HIV-1 vaccine is likely to have the greatest impact on viral transmission rates. As previous reports have implicated DNA-priming, protein boost regimens to be efficient activators of humoral responses, we sought to optimize this regimen to further augment vaccine immunogenicity. Here we evaluated single versus concurrent intradermal (i.d.) and intramuscular (i.m.) vaccinations as a DNA-priming strategy for their abilities to elicit humoral and cellular responses against a model HIV-1 vaccine antigen, CN54-gp140. To further augment vaccine-elicited T and B cell responses, we enhanced cellular transfection with electroporation and then boosted the DNA-primed responses with homologous protein delivered subcutaneously (s.c.), intranasally (i.n.), i.m., or transcutaneously (t.c.). In mice, the concurrent priming regimen resulted in significantly elevated gamma interferon T cell responses and high-avidity antigen-specific IgG B cell responses, a hallmark of B cell maturation. Protein boosting of the concurrent DNA strategy further enhanced IgG concentrations but had little impact on T cell reactivity. Interestingly protein boosting by the subcutaneous route increased antibody avidity to a greater extent than protein boosting by either the i.m., i.n., or t.c. route, suggesting that this route may be preferential for driving B cell maturation. Using an alternative and larger animal model, the rabbit, we found the concurrent DNA-priming strategy followed by s.c. protein boosting to again be capable of eliciting high-avidity humoral responses and to also be able to neutralize HIV-1 pseudoviruses from diverse clades (clades A, B, and C). Taken together, we show that concurrent multiple-route DNA vaccinations induce strong cellular immunity, in addition to potent and high-avidity humoral immune responses. The route of vaccination has profound effects on prevailing immune responses. Due to the insufficient immunogenicity and

  8. Efavirenz Enhances HIV-1 Gag Processing at the Plasma Membrane through Gag-Pol Dimerization

    Science.gov (United States)

    Sudo, Sho; Haraguchi, Hiyori; Hirai, Yoko; Gatanaga, Hiroyuki; Sakuragi, Jun-ichi; Momose, Fumitaka

    2013-01-01

    Efavirenz (EFV), a nonnucleoside reverse transcriptase (RT) inhibitor, also inhibits HIV-1 particle release through enhanced Gag/Gag-Pol processing by protease (PR). To better understand the mechanisms of the EFV-mediated enhancement of Gag processing, we examined the intracellular localization of Gag/Gag-Pol processing products and their precursors. Confocal microscopy revealed that in the presence of EFV, the N-terminal p17 matrix (p17MA) fragment was uniformly distributed at the plasma membrane (PM) but the central p24 capsid (p24CA) and the Pol-encoded RT antigens were diffusely distributed in the cytoplasm, and all of the above were observed in puncta at the PM in the absence of EFV. EFV did not impair PM targeting of Gag/Gag-Pol precursors. Membrane flotation analysis confirmed these findings. Such uniform distribution of p17MA at the PM was not seen by overexpression of Gag-Pol and was suppressed when EFV-resistant HIV-1 was used. Forster's fluorescence resonance energy transfer assay revealed that Gag-Pol precursor dimerization occurred mainly at the PM and that EFV induced a significant increase of the Gag-Pol dimerization at the PM. Gag-Pol dimerization was not enhanced when HIV-1 contained the EFV resistance mutation in RT. Bacterial two-hybrid assay showed that EFV enhanced the dimerization of PR-RT fragments and restored the dimerization impaired by the dimerization-defective mutation in the RT tryptophan repeat motif but not that impaired by the mutation at the PR dimer interface. Collectively, our data indicate that EFV enhances Gag-Pol precursor dimerization, likely after PM targeting but before complete particle assembly, resulting in uniform distribution of p17MA to and dissociation of p24CA and RT from the PM. PMID:23302874

  9. HIV

    African Journals Online (AJOL)

    Introduction. The·human immunodeficiency virus (HIV) can be transmiHed from one person to onother through the use of non-sterile nee- dles, syringes, and other skin-piercing and invasive instruments. Proper .sterilization of all such instruments is therefore important to prevent its transmission. HIV is very sensitive to ...

  10. hiv

    African Journals Online (AJOL)

    2016-03-31

    Mar 31, 2016 ... Indexed By: African Journal Online (AJOL); Texila American University; Genamics; Scholarsteer; EIJASR; CAS-American Chemical. Society; and IRMS Informatics India (J-Gate). ABSTRACT. This study evaluated the effect of HIV infection on CD4 T-lymphocyte depletion in people living with HIV/AIDS.

  11. Equity and efficiency in HIV-treatment in South Africa: the contribution of mathematical programming to priority setting.

    Science.gov (United States)

    Cleary, Susan; Mooney, Gavin; McIntyre, Di

    2010-10-01

    The HIV-epidemic is one of the greatest public health crises to face South Africa. A health care response to the treatment needs of HIV-positive people is a prime example of the desirability of an economic, rational approach to resource allocation in the face of scarcity. Despite this, almost no input based on economic analysis is currently used in national strategic planning. While cost-utility analysis is theoretically able to establish technical efficiency, in practice this is accomplished by comparing an intervention's ICER to a threshold level representing society's maximum willingness to pay to avoid death and improve health-related quality of life. Such an approach has been criticised for a number of reasons, including that it is inconsistent with a fixed budget for health care and that equity is not taken into account. It is also impractical if no national policy on the threshold exists. As an alternative, this paper proposes a mathematical programming approach that is capable of highlighting technical efficiency, equity, the equity/efficiency trade-off and the affordability of alternative HIV-treatment interventions. Government could use this information to plan an HIV-treatment strategy that best meets equity and efficiency objectives within budget constraints.

  12. A sensitive HIV-1 envelope induced fusion assay identifies fusion enhancement of thrombin

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, De-Chun; Zhong, Guo-Cai; Su, Ju-Xiang [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Liu, Yan-Hong [Second Affiliated Hospital of Harbin Medical University, 246 Xuefu Road, Harbin, Heilongjiang 150081 (China); Li, Yan; Wang, Jia-Ye [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Hattori, Toshio [Department of Emerging Infectious Diseases, Division of Internal Medicine, Graduate School of Medicine, Tohoku University, Sendai 9808574 (Japan); Ling, Hong, E-mail: lingh@ems.hrbmu.edu.cn [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Department of Parasitology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Key Lab of Heilongjiang Province for Infection and Immunity, Key Lab of Heilongjiang Province Education Bureau for Etiology, Harbin, Heilongjiang 150081 (China); Zhang, Feng-Min, E-mail: fengminzhang@yahoo.com.cn [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Key Lab of Heilongjiang Province for Infection and Immunity, Key Lab of Heilongjiang Province Education Bureau for Etiology, Harbin, Heilongjiang 150081 (China)

    2010-01-22

    To evaluate the interaction between HIV-1 envelope glycoprotein (Env) and target cell receptors, various cell-cell-fusion assays have been developed. In the present study, we established a novel fusion system. In this system, the expression of the sensitive reporter gene, firefly luciferase (FL) gene, in the target cells was used to evaluate cell fusion event. Simultaneously, constitutively expressed Renilla luciferase (RL) gene was used to monitor effector cell number and viability. FL gave a wider dynamic range than other known reporters and the introduction of RL made the assay accurate and reproducible. This system is especially beneficial for investigation of potential entry-influencing agents, for its power of ruling out the false inhibition or enhancement caused by the artificial cell-number variation. As a case study, we applied this fusion system to observe the effect of a serine protease, thrombin, on HIV Env-mediated cell-cell fusion and have found the fusion enhancement activity of thrombin over two R5-tropic HIV strains.

  13. Assessing the relevance, efficiency, and sustainability of HIV/AIDS in-service training in Nigeria.

    Science.gov (United States)

    Burlew, Randi; Puckett, Amanda; Bailey, Rebecca; Caffrey, Margaret; Brantley, Stephanie

    2014-04-17

    More than three million people in Nigeria are living with HIV/AIDS. In order to reduce the HIV/AIDS burden in Nigeria, the US Government (USG) has dedicated significant resources to combating the epidemic through the President's Emergency Plan for AIDS Relief (PEPFAR). In-service training (IST) of health workers is one of the most commonly used strategies to improve the quality and coverage of HIV/AIDS services. At USAID/Nigeria's request, the USAID-funded CapacityPlus project conducted an assessment of PEPFAR-funded IST for all cadres of health workers in Nigeria. Using the IST Improvement Framework, developed by the USAID Applying Sciences to Strengthen and Improve Systems Project (ASSIST), as a guide, the authors developed a survey tool to assess the efficiency, effectiveness and sustainability of IST provided between January 2007 and July 2012 by PEPFAR-funded implementing partners in Nigeria. The instrument was adapted to the Nigerian context and refined through a stakeholder engagement process. It was then distributed via an online platform to more than 50 PEPFAR-funded implementing partners who provided IST in Nigeria. A total of 39 implementing partners completed the survey. Our survey found that PEPFAR implementing partners have been providing a wide range of IST to a diverse group of health workers in Nigeria since 2007. Most trainings are developed using national curricula, manuals and/or other standard operating procedures. Many of the partners are conducting Training Needs Assessments to inform the planning, design and development of their training programs. However, the assessment also pointed to a number of recommendations to increase the efficiency, effectiveness and sustainability of PEPFAR-funded IST. These actions are as follows: improve collaboration and coordination among implementing partners; apply a more diverse and cost-effective set of training modalities; allocate funding specifically for the evaluation of the effectiveness of training

  14. ADAR1 and PACT contribute to efficient translation of transcripts containing HIV-1 trans-activating response (TAR) element.

    Science.gov (United States)

    Chukwurah, Evelyn; Handy, Indhira; Patel, Rekha C

    2017-03-23

    Human immunodeficiency virus type 1 (HIV-1) has evolved various measures to counter the host cell's innate antiviral response during the course of infection. Interferon (IFN)-stimulated gene products are produced following HIV-1 infection to limit viral replication, but viral proteins and RNAs counteract their effect. One such mechanism is specifically directed against the IFN-induced Protein Kinase PKR, which is centrally important to the cellular antiviral response. In the presence of viral RNAs, PKR is activated and phosphorylates the translation initiation factor eIF2α. This shuts down the synthesis of both host and viral proteins, allowing the cell to mount an effective antiviral response. PACT (protein activator of PKR) is a cellular protein activator of PKR, primarily functioning to activate PKR in response to cellular stress. Recent studies have indicated that during HIV-1 infection, PACT's normal cellular function is compromised and that PACT is unable to activate PKR. Using various reporter systems and in vitro kinase assays, we establish in this report that interactions between PACT, ADAR1 and HIV-1-encoded Tat protein diminish the activation of PKR in response to HIV-1 infection. Our results highlight an important pathway by which HIV-1 transcripts subvert the host cell's antiviral activities to enhance their translation. © 2017 The Author(s).

  15. HIV-1 Tat Protein Enhances Expression and Function of Breast Cancer Resistance Protein.

    Science.gov (United States)

    Zhou, Yancong; Zhang, Kun; Yin, Xiaojie; Nie, Qichang; Ma, Yonggang

    2016-01-01

    ATP binding cassette (ABC) transporters can transfer a variety of antiviral agents from the cytoplasm to body fluid, which results in a reduced intracellular concentration of the drugs. Proteins of HIV-1, e.g., Tat and gp120, altered some types of ABC transporter expression in brain microvascular endothelial cells and astrocytes. However, the effect of Tat on ABC transporters in T lymphocytes is unclear. In this study the status of breast cancer resistance protein (BCRP) in Tat expressing cell lines was examined with real-time PCR and flow cytometry. It was found that HIV-1 Tat protein upregulated BCRP expression and enhanced efflux mediated by BCRP significantly, which could inhibit antiviral drugs from entering infected cells and interfere with the therapeutic effect of HAART.

  16. Using quartz sand to enhance the removal efficiency of M. aeruginosa by inorganic coagulant and achieve satisfactory settling efficiency

    OpenAIRE

    Pei, Haiyan; Jin, Yan; Xu, Hangzhou; Ma, Chunxia; Sun, Jiongming; Li, Hongmin

    2017-01-01

    In this study, low-cost and non-polluting quartz sand was respectively mixed with AlCl3, FeCl3 and PAFC to synergistically remove Microcystis aeruginosa. Results showed that quartz sand could markedly increase the algae removal efficiency and decrease the coagulant doses. The increase of removal efficiency with AlCl3 and FeCl3 was only due to the enhancement of floc density by the quartz sand. However, the removal efficiency with PAFC was increased not only by the enhanced floc density, but a...

  17. Balancing efficiency, equity and feasibility of HIV treatment in South Africa

    DEFF Research Database (Denmark)

    Baltussen, Rob; Mikkelsen, Evelinn; Tromp, Noor

    2013-01-01

    South Africa, the country with the largest HIV epidemic worldwide, has been scaling up treatment since 2003 and is rapidly expanding its eligibility criteria. The HIV treatment programme has achieved significant results, and had 1.8 million people on treatment per 2011. Despite these achievements...... on the design of the present HIV treatment programme in South Africa can be considered suboptimal. We argue there are two fundamental reasons to this. First, while there is a rapidly growing evidence-base to guide priority setting decisions on HIV treatment, its included studies typically consider only one......, and holds large potential to improve HIV priority setting in South Africa....

  18. Potential impact of enhanced practice efficiency on endoscopy waiting times.

    LENUS (Irish Health Repository)

    Harewood, G C

    2009-06-01

    With the growing demand on endoscopy services, optimising practice efficiency has assumed increasing importance. Prior research has identified practice changes, which increase the efficiency in endoscopy. In this study, the potential impact of these practice changes on the current and projected future endoscopy waiting times at our institution was assessed.

  19. HIV-1 Tat protein enhances the intracellular growth of Leishmania amazonensis via the ds-RNA induced protein PKR.

    Science.gov (United States)

    Vivarini, Áislan de Carvalho; Pereira, Renata de Meirelles Santos; Barreto-de-Souza, Victor; Temerozo, Jairo Ramos; Soares, Deivid C; Saraiva, Elvira M; Saliba, Alessandra Mattos; Bou-Habib, Dumith Chequer; Lopes, Ulisses Gazos

    2015-11-26

    HIV-1 co-infection with human parasitic diseases is a growing public health problem worldwide. Leishmania parasites infect and replicate inside macrophages, thereby subverting host signaling pathways, including the response mediated by PKR. The HIV-1 Tat protein interacts with PKR and plays a pivotal role in HIV-1 replication. This study shows that Tat increases both the expression and activation of PKR in Leishmania-infected macrophages. Importantly, the positive effect of Tat addition on parasite growth was dependent on PKR signaling, as demonstrated in PKR-deficient macrophages or macrophages treated with the PKR inhibitor. The effect of HIV-1 Tat on parasite growth was prevented when the supernatant of HIV-1-infected macrophages was treated with neutralizing anti-HIV-1 Tat prior to Leishmania infection. The addition of HIV-1 Tat to Leishmania-infected macrophages led to inhibition of iNOS expression, modulation of NF-kB activation and enhancement of IL-10 expression. Accordingly, the expression of a Tat construct containing mutations in the basic region (49-57aa), which is responsible for the interaction with PKR, favored neither parasite growth nor IL-10 expression in infected macrophages. In summary, we show that Tat enhances Leishmania growth through PKR signaling.

  20. High prevalence of tuberculosis in newly enrolled HIV patients in Zambia: need for enhanced screening approach.

    Science.gov (United States)

    Henostroza, G; Harris, J B; Chitambi, R; Siyambango, M; Turnbull, E R; Maggard, K R; Krüüner, A; Kapata, N; Reid, S E

    2016-08-01

    Tuberculosis (TB) remains a leading cause of morbidity and mortality in sub-Saharan Africa. In Zambia, smear microscopy and chest radiography (CXR) are the primary TB diagnostic tools, and most cases are not bacteriologically confirmed. We implemented enhanced screening to determine the TB burden among new human immunodeficiency virus (HIV) clinic enrollees. Consecutive adult HIV clinic enrollees were screened, regardless of symptoms. All underwent microscopy (Ziehl-Neelsen/fluorescence microscopy) on three sputum specimens, physical examination, and digital CXR. Sputum, blood and urine specimens were cultured. Xpert(®) MTB/RIF testing was performed retrospectively. From July 2011 to April 2012, 399 patients were enrolled. The median age was 34.4 years; body mass index was 20.8 kg/m(2), CD4 count was 202 cells/μl and 86% were symptomatic. Culture-confirmed TB was diagnosed in 72/399 (18%) patients; an additional 31/399 (8%) were culture-negative but diagnosed clinically. Symptom screening for any cough, fever, weight loss or night sweats had high sensitivity (95%) but low specificity (14%) for detecting culture-confirmed cases. Among culture-confirmed cases, 35/72 (49%) were missed clinically and detected only by culture. Xpert was 64% sensitive and 98% specific. High TB prevalence was found in Zambians newly enrolled into HIV care. Screening with sensitive diagnostics should be considered with culture when feasible in this population.

  1. Enhanced immunogenicity of HIV-1 envelope gp140 proteins fused to APRIL.

    Science.gov (United States)

    Isik, Gözde; Sliepen, Kwinten; van Montfort, Thijs; Sanders, Rogier W

    2014-01-01

    Current HIV-1 vaccines based on the HIV-1 envelope glycoprotein spike (Env), the only relevant target for broadly neutralizing antibodies, are unable to induce protective immunity. Env immunogenicity can be enhanced by fusion to costimulatory molecules involved in B cell activation, such as APRIL and CD40L. Here, we found that Env-APRIL signaled through the two receptors, BCMA and TACI. In rabbits, Env-APRIL induced significantly higher antibody responses against Env compared to unconjugated Env, while the antibody responses against the APRIL component were negligible. To extend this finding, we tested Env-APRIL in mice and found minimal antibody responses against APRIL. Furthermore, Env-CD40L did not induce significant anti-CD40L responses. Thus, in contrast to the 4-helix cytokines IL-21 and GM-CSF, the TNF-superfamily members CD40L and APRIL induced negligible autoantibodies. This study confirms and extends previous work and shows that fusion of Env-based immunogens to APRIL can improve Env immunogenicity and might help in designing HIV vaccines that induce protective humoral immunity.

  2. Enhanced immunogenicity of HIV-1 envelope gp140 proteins fused to APRIL.

    Directory of Open Access Journals (Sweden)

    Gözde Isik

    Full Text Available Current HIV-1 vaccines based on the HIV-1 envelope glycoprotein spike (Env, the only relevant target for broadly neutralizing antibodies, are unable to induce protective immunity. Env immunogenicity can be enhanced by fusion to costimulatory molecules involved in B cell activation, such as APRIL and CD40L. Here, we found that Env-APRIL signaled through the two receptors, BCMA and TACI. In rabbits, Env-APRIL induced significantly higher antibody responses against Env compared to unconjugated Env, while the antibody responses against the APRIL component were negligible. To extend this finding, we tested Env-APRIL in mice and found minimal antibody responses against APRIL. Furthermore, Env-CD40L did not induce significant anti-CD40L responses. Thus, in contrast to the 4-helix cytokines IL-21 and GM-CSF, the TNF-superfamily members CD40L and APRIL induced negligible autoantibodies. This study confirms and extends previous work and shows that fusion of Env-based immunogens to APRIL can improve Env immunogenicity and might help in designing HIV vaccines that induce protective humoral immunity.

  3. Optical Downconverting Nanomaterials for Enhanced Photovoltaic Efficiency Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For photovoltaic cells used to power space missions, such as those based on silicon, CuInGaSe2, and III-V materials, optical-to-electrical conversion efficiency is...

  4. Graphene substrates enhance optical transfection efficiency in pluripotent stem cells

    CSIR Research Space (South Africa)

    Khanyile, T

    2013-09-01

    Full Text Available on graphene coated glass resulted in an improvement in optical transfection efficiencies. Future perspectives involve the testing of cytokines, growth factors and integrins to investigate the stimulation of extracellular matrix through graphene...

  5. Efficiency enhancement of InGaN amber MQWs using nanopillar structures

    DEFF Research Database (Denmark)

    Ou, Yiyu; Iida, Daisuke; Liu, Jin

    2018-01-01

    We have investigated the use of nanopillar structures on high indium content InGaN amber multiple quantum well (MQW) samples to enhance the emission efficiency. A significant emission enhancement was observed which can be attributed to the enhancement of internal quantum efficiency and light...... extraction efficiency. The size-dependent strain relaxation effect was characterized by photoluminescence, Raman spectroscopy and time-resolved photoluminescence measurements. In addition, the light extraction efficiency of different MQW samples was studied by finite-different time-domain simulations...

  6. Abbreviated HIV counselling and testing and enhanced referral to care in Uganda: a factorial randomised controlled trial.

    Science.gov (United States)

    Wanyenze, Rhoda K; Kamya, Moses R; Fatch, Robin; Mayanja-Kizza, Harriet; Baveewo, Steven; Szekeres, Gregory; Bangsberg, David R; Coates, Thomas; Hahn, Judith A

    2013-09-01

    HIV counselling and testing and linkage to care are crucial for successful HIV prevention and treatment. Abbreviated counselling could save time; however, its effect on HIV risk is uncertain and methods to improve linkage to care have not been studied. We did this factorial randomised controlled study at Mulago Hospital, Uganda. Participants were randomly assigned to abbreviated or traditional HIV counselling and testing; HIV-infected patients were randomly assigned to enhanced linkage to care or standard linkage to care. All study personnel except counsellors and the data officer were masked to study group assignment. Participants had structured interviews, given once every 3 months. We compared sexual risk behaviour by counselling strategy with a 6·5% non-inferiority margin. We used Cox proportional hazards analyses to compare HIV outcomes by linkage to care over 1 year and tested for interaction by sex. This trial is registered with ClinicalTrials.gov (NCT00648232). We enrolled 3415 participants; 1707 assigned to abbreviated counselling versus 1708 assigned to traditional. Unprotected sex with an HIV discordant or status unknown partner was similar in each group (232/823 [27·9%] vs 251/890 [28·2%], difference -0·3%, one-sided 95% CI 3·2). Loss to follow-up was lower for traditional counselling than for abbreviated counselling (adjusted hazard ratio [HR] 0·61, 95% CI 0·44-0·83). 1003 HIV-positive participants were assigned to enhanced linkage (n=504) or standard linkage to care (n=499). Linkage to care did not have a significant effect on mortality or receipt of co-trimoxazole. Time to treatment in men with CD4 cell counts of 250 cells per μL or fewer was lower for enhanced linkage versus standard linkage (adjusted HR 0·60, 95% CI 0·41-0·87) and time to HIV care was decreased among women (0·80, 0·66-0·96). Abbreviated HIV counselling and testing did not adversely affect risk behaviour. Linkage to care interventions might decrease time to enrolment

  7. Efficacy of enhanced HIV counseling for risk reduction during pregnancy and in the postpartum period: a randomized controlled trial.

    Directory of Open Access Journals (Sweden)

    Suzanne Maman

    Full Text Available INTRODUCTION: Pregnancy and the postpartum period present important intervention opportunities. Counseling can leverage the motivation women have during this time to change behaviors that may negatively affect their health and the heath of their infants. METHODS: Pregnant women attending an antenatal clinic in South Africa were randomly allocated to treatment (n=733 and control arms (n=747. Treatment arm participants received enhanced HIV pre- and post-test counseling, legal support and access to support groups at baseline, which occurred at the first antenatal visit, and then six and ten weeks postpartum. Control arm participants received standard HIV testing and counseling (HTC and two postpartum attention control sessions. Outcomes were incidence of sexually transmitted infection (STI by 14 weeks postpartum and past 30-day inconsistent condom use at 14 weeks and 9 months postpartum. RESULTS: There were no intervention effects on incident STIs for either HIV-negative (adjusted risk ratio (aRR 1.01, 95% CI 0.71-1.44 or HIV-positive participants (aRR 0.86, 95% CI 0.61-1.23. The intervention was associated with a 28% decrease in risk of past 30-day inconsistent condom use at nine-months among HIV-negative women (aRR 0.72,95% CI 0.59-0.88, but did not affect inconsistent condom use among HIV-positive women (aRR1.08; 95% CI 0.67-1.75. DISCUSSION: An enhanced counseling intervention during pregnancy and the postpartum period can lead to reductions in inconsistent condom use among HIV-negative women. Results underscore the importance of the counseling that accompanies HIV HTC. More work is needed to understand how to promote and sustain risk reduction among HIV-positive women. TRIAL REGISTRATION: ClinicalTrials.gov NCT01683461.

  8. Enhancing Solar Cell Efficiency Using Photon Upconversion Materials

    Science.gov (United States)

    Shang, Yunfei; Hao, Shuwei; Yang, Chunhui; Chen, Guanying

    2015-01-01

    Photovoltaic cells are able to convert sunlight into electricity, providing enough of the most abundant and cleanest energy to cover our energy needs. However, the efficiency of current photovoltaics is significantly impeded by the transmission loss of sub-band-gap photons. Photon upconversion is a promising route to circumvent this problem by converting these transmitted sub-band-gap photons into above-band-gap light, where solar cells typically have high quantum efficiency. Here, we summarize recent progress on varying types of efficient upconversion materials as well as their outstanding uses in a series of solar cells, including silicon solar cells (crystalline and amorphous), gallium arsenide (GaAs) solar cells, dye-sensitized solar cells, and other types of solar cells. The challenge and prospect of upconversion materials for photovoltaic applications are also discussed. PMID:28347095

  9. Efficiency enhancements for MCP-based beta autoradiography imaging

    CERN Document Server

    Lees, J E

    2002-01-01

    We describe three approaches to increase the beta detection efficiency of microchannel plate detectors for biological beta autoradiography:(a)reversing the microchannel plate (MCP) bias polarity, changing the conventional high negative voltage on the input MCP to a grounded input, (b) a reduction in MCP pore size from 12.5 to 6 mu m, (c) using a CsI coating as an efficient secondary electron emitter. We also present our first measurements of double-tracer ( sup 3 H and sup 1 sup 4 C) imaging using pulse height analysis to distinguish between isotopes.

  10. Using Backscattering to Enhance Efficiency in Neutron Detectors

    DEFF Research Database (Denmark)

    Kittelmann, T.; Kanaki, K.; Klinkby, Esben Bryndt

    2017-01-01

    The principle of using strongly scattering materials to recover efficiency in detectors for neutron instruments, via backscattering of unconverted thermal neutrons, is discussed in general. The feasibility of the method is illustrated through Geant4-based simulations involving thermal neutrons...... impinging on a specific setup with a layer of polyethylene placed behind a single-layered boron-10 thin-film gaseous detector. The results show that detection efficiencies can be as much as doubled in the most ideal scenario, but with associated adverse contributions to spatial and timing resolutions of...

  11. Efficient contrast enhancement through log-power histogram modification

    NARCIS (Netherlands)

    Wu, T.; Toet, A.

    2014-01-01

    A simple power-logarithm histogram modification operator is proposed to enhance digital image contrast. First a logarithm operator reduces the effect of spikes and transforms the image histogram into a smoothed one that approximates a uniform histogram while retaining the relative size ordering of

  12. A simple and efficient procedure to enhance artemisinin content in ...

    African Journals Online (AJOL)

    SERVER

    2007-06-18

    Jun 18, 2007 ... antimalarial drug: biochemical and molecular approaches for enhanced production. Planta Med. 69: 289-299. Aharoni A, Jongsma MA, Bouwmeester HJ (2005). Volatile science. Metabolic engineering of terpenoids in plants. Trends Plant Sci. 10: 594-602. Avery MA, Chong WKM, Jennings-White C (1992).

  13. A simple and efficient procedure to enhance artemisinin content in ...

    African Journals Online (AJOL)

    SERVER

    2007-06-18

    Jun 18, 2007 ... duction in A. annua and our result demonstrated that by simply treating A. annua with NaCl, the content of artemisinin in the plant could be significantly enhanced. MATERIALS AND METHODS. Plant material, growth condition and salinity treatments. A. annua L. was collected from Sichuan Province, China.

  14. Phytoremediation of heavy metals with several efficiency enhancer ...

    African Journals Online (AJOL)

    It is no doubt that the contamination of water, air and soil has worsened, and this occurs as a result of the increase in population. However, the need for remediation technologies has to be seriously considered. Phytoremediation is one of the remediation techniques with a relatively slow procedure and low efficiency.

  15. DNA supercoiling enhances cooperativity and efficiency of an epigenetic switch

    DEFF Research Database (Denmark)

    Norregaard, Kamilla; Andersson, Magnus; Sneppen, Kim

    2013-01-01

    Bacteriophage λ stably maintains its dormant prophage state but efficiently enters lytic development in response to DNA damage. The mediator of these processes is the λ repressor protein, CI, and its interactions with λ operator DNA. This λ switch is a model on the basis of which epigenetic switc...

  16. Enhanced efficiency in double junction polymer: Fullerene solar cells

    NARCIS (Netherlands)

    Moet, D.J.D.; Bruyn, P. de; Kotlarski, J.D.; Blom, P.W.M.

    2010-01-01

    Polymer solar cells based on the polyfluorene copolymer poly[9,9-didecanefluorene-alt-(bis-thienylene) benzothiadiazole] (PF10TBT) and the fullerene derivative [6,6]-phenyl C61-butyric acid methyl ester (PCBM) exhibit a power conversion efficiency of 4%. However, the optimum thickness of the

  17. Enhancement of callus induction and regeneration efficiency from ...

    African Journals Online (AJOL)

    Carbon source in the medium is considered to be an essential component for the high production costs of callus and plantlets in tissue culture. We report here the establishment of an efficient tissue culture cycle (callus induction and plant regeneration) for Datura stramonium by adjusting carbon sources and concentrations.

  18. Enhancing Instructional Design Efficiency: Methodologies Employed by Instructional Designers

    Science.gov (United States)

    Roytek, Margaret A.

    2010-01-01

    Instructional systems design (ISD) has been frequently criticised as taking too long to implement, calling for a reduction in cycle time--the time that elapses between project initiation and delivery. While instructional design research has historically focused on increasing "learner" efficiencies, the study of what instructional designers do to…

  19. How bilayer excitons can greatly enhance thermoelectric efficiency

    Science.gov (United States)

    Wu, Kai; Rademaker, Louk; Zaanen, Jan

    2015-03-01

    Presently, a major nanotechnological challenge is to design thermoelectric devices that have a high figure of merit. To that end, we propose to use bilayer excitons in two-dimensional nanostructures. Bilayer exciton systems are shown to have an improved thermopower and an enhanced electric counterflow and thermal conductivity, with respect to regular semiconductor-based thermoelectrics. We suggest an experimental realization of a bilayer exciton thermocouple. Based on current experimental parameters, a bilayer exciton heterostructures of p- and n-doped Bi2Te3 can enhance the figure of merit an order of magnitude compared to bulk Bi2Te3. Another material suggestion is to make a bilayer out of electron-doped SrTiO3 and hole-doped Ca3Co4O9.

  20. The Effect of Multispectral Image Fusion Enhancement on Human Efficiency

    Science.gov (United States)

    2017-03-20

    describe a rapid- innovation challenge to combat and deal with the problem of internal, insider physical threats (e.g., active shooters) and...designed to be innovative , low-cost, and (relatively) easy-to-implement, and to provide support across the spectrum of possible users including...Aerospace & Technologies Corp., 2875 Presidential Drive, Fairborn, OH 45324, USA visual enhancements are particularly important in appli- cations of

  1. Absorption enhancement in graphene with an efficient resonator

    DEFF Research Database (Denmark)

    Xiao, Binggang; Gu, Mingyue; Qin, Kang

    2017-01-01

    Graphene can be utilized in designing tunable terahertz (THz) devices due to its tunability of sheet conductivity, suffering however with weak light-graphene interactions. In this paper, an absorption enhancement in graphene using a Fabry–Perot resonator is presented, and its performance has been...... of graphene which could be conveniently achieved by applying a bias voltage. The proposed structure here has a promising potential for developing advanced THz optics-electronics devices....

  2. Energy Efficiency and Productivity Enhancement of Microbial Electrosynthesis of Acetate

    Directory of Open Access Journals (Sweden)

    Edward V. LaBelle

    2017-05-01

    Full Text Available It was hypothesized that a lack of acetogenic biomass (biocatalyst at the cathode of a microbial electrosynthesis system, due to electron and nutrient limitations, has prevented further improvement in acetate productivity and efficiency. In order to increase the biomass at the cathode and thereby performance, a bioelectrochemical system with this acetogenic community was operated under galvanostatic control and continuous media flow through a reticulated vitreous carbon (RVC foam cathode. The combination of galvanostatic control and the high surface area cathode reduced the electron limitation and the continuous flow overcame the nutrient limitation while avoiding the accumulation of products and potential inhibitors. These conditions were set with the intention of operating the biocathode through the production of H2. Biofilm growth occurred on and within the unmodified RVC foam regardless of vigorous H2 generation on the cathode surface. A maximum volumetric rate or space time yield for acetate production of 0.78 g/Lcatholyte/h was achieved with 8 A/Lcatholyte (83.3 A/m2projected surface area of cathode supplied to the continuous flow/culture bioelectrochemical reactors. The total Coulombic efficiency in H2 and acetate ranged from approximately 80–100%, with a maximum of 35% in acetate. The overall energy efficiency ranged from approximately 35–42% with a maximum to acetate of 12%.

  3. Using quartz sand to enhance the removal efficiency of M. aeruginosa by inorganic coagulant and achieve satisfactory settling efficiency.

    Science.gov (United States)

    Pei, Haiyan; Jin, Yan; Xu, Hangzhou; Ma, Chunxia; Sun, Jiongming; Li, Hongmin

    2017-10-19

    In this study, low-cost and non-polluting quartz sand was respectively mixed with AlCl3, FeCl3 and PAFC to synergistically remove Microcystis aeruginosa. Results showed that quartz sand could markedly increase the algae removal efficiency and decrease the coagulant doses. The increase of removal efficiency with AlCl3 and FeCl3 was only due to the enhancement of floc density by the quartz sand. However, the removal efficiency with PAFC was increased not only by the enhanced floc density, but also by the enlarged floc size. Flocs from 50 mg/L sand addition were larger than that with other sand doses, which was on account of the appropriate enhancement of collision efficiency at this dose. After coagulation, the extracellular organic matter (EOM) and microcystins (MCs) in system with quartz sand was remarkably reduced. That's because quartz sand can enhance the coagulation so as to improve capping the EOM and MCs in flocs during coagulation process. Owing to 200 mg/L quartz sand could damage the cell's membrane during coagulation proces, algal cells in the system lysed two days earlier than with 50 mg/L sand during flocs storage. In addition, cells with PAFC incurred relatively moderate cellular oxidative damage and could remain intact for longer time.

  4. Enhanced extraction efficiency of fluorescent SiC by surface nanostructuring

    DEFF Research Database (Denmark)

    Ou, Yiyu; Jokubavicius, Valdas; Yakimova, Rositza

    2012-01-01

    Antireflective structures were fabricated on fluorescent 6H-SiC for white LEDs to enhance the extraction efficiency. Average surface reflectance decreased from 22.1% to 5.1% over a broad range, and luminescence intensity was enhanced by 41%.......Antireflective structures were fabricated on fluorescent 6H-SiC for white LEDs to enhance the extraction efficiency. Average surface reflectance decreased from 22.1% to 5.1% over a broad range, and luminescence intensity was enhanced by 41%....

  5. Biological optimization systems for enhancing photosynthetic efficiency and methods of use

    Science.gov (United States)

    Hunt, Ryan W.; Chinnasamy, Senthil; Das, Keshav C.; de Mattos, Erico Rolim

    2012-11-06

    Biological optimization systems for enhancing photosynthetic efficiency and methods of use. Specifically, methods for enhancing photosynthetic efficiency including applying pulsed light to a photosynthetic organism, using a chlorophyll fluorescence feedback control system to determine one or more photosynthetic efficiency parameters, and adjusting one or more of the photosynthetic efficiency parameters to drive the photosynthesis by the delivery of an amount of light to optimize light absorption of the photosynthetic organism while providing enough dark time between light pulses to prevent oversaturation of the chlorophyll reaction centers are disclosed.

  6. Photonic multilayer structure of Begonia chloroplasts enhances photosynthetic efficiency.

    Science.gov (United States)

    Jacobs, Matthew; Lopez-Garcia, Martin; Phrathep, O-Phart; Lawson, Tracy; Oulton, Ruth; Whitney, Heather M

    2016-10-24

    Enhanced light harvesting is an area of interest for optimizing both natural photosynthesis and artificial solar energy capture1,2. Iridescence has been shown to exist widely and in diverse forms in plants and other photosynthetic organisms and symbioses3,4, but there has yet to be any direct link demonstrated between iridescence and photosynthesis. Here we show that epidermal chloroplasts, also known as iridoplasts, in shade-dwelling species of Begonia5, notable for their brilliant blue iridescence, have a photonic crystal structure formed from a periodic arrangement of the light-absorbing thylakoid tissue itself. This structure enhances photosynthesis in two ways: by increasing light capture at the predominantly green wavelengths available in shade conditions, and by directly enhancing quantum yield by 5-10% under low-light conditions. These findings together imply that the iridoplast is a highly modified chloroplast structure adapted to make best use of the extremely low-light conditions in the tropical forest understorey in which it is found5,6. A phylogenetically diverse range of shade-dwelling plant species has been found to produce similarly structured chloroplasts7-9, suggesting that the ability to produce chloroplasts whose membranes are organized as a multilayer with photonic properties may be widespread. In fact, given the well-established diversity and plasticity of chloroplasts10,11, our results imply that photonic effects may be important even in plants that do not show any obvious signs of iridescence to the naked eye but where a highly ordered chloroplast structure may present a clear blue reflectance at the microscale. Chloroplasts are generally thought of as purely photochemical; we suggest that one should also think of them as a photonic structure with a complex interplay between control of light propagation, light capture and photochemistry.

  7. Temporal adaptation enhances efficient contrast gain control on natural images.

    Directory of Open Access Journals (Sweden)

    Fabian Sinz

    Full Text Available Divisive normalization in primary visual cortex has been linked to adaptation to natural image statistics in accordance to Barlow's redundancy reduction hypothesis. Using recent advances in natural image modeling, we show that the previously studied static model of divisive normalization is rather inefficient in reducing local contrast correlations, but that a simple temporal contrast adaptation mechanism of the half-saturation constant can substantially increase its efficiency. Our findings reveal the experimentally observed temporal dynamics of divisive normalization to be critical for redundancy reduction.

  8. Efficient Inhibition of HIV Replication in the Gastrointestinal and Female Reproductive Tracts of Humanized BLT Mice by EFdA.

    Directory of Open Access Journals (Sweden)

    Uma Shanmugasundaram

    Full Text Available The nucleoside reverse transcriptase inhibitor (NRTI 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA in preclinical development exhibits improved safety and antiviral activity profiles with minimal drug resistance compared to approved NRTIs. However, the systemic antiviral efficacy of EFdA has not been fully evaluated. In this study, we utilized bone marrow/liver/thymus (BLT humanized mice to investigate the systemic effect of EFdA treatment on HIV replication and CD4+ T cell depletion in the peripheral blood (PB and tissues. In particular, we performed a comprehensive analysis of the female reproductive tract (FRT and gastrointestinal (GI tract, major sites of transmission, viral replication, and CD4+ T cell depletion and where some current antiretroviral drugs have a sub-optimal effect.EFdA treatment resulted in reduction of HIV-RNA in PB to undetectable levels in the majority of treated mice by 3 weeks post-treatment. HIV-RNA levels in cervicovaginal lavage of EFdA-treated BLT mice also declined to undetectable levels demonstrating strong penetration of EFdA into the FRT. Our results also demonstrate a strong systemic suppression of HIV replication in all tissues analyzed. In particular, we observed more than a 2-log difference in HIV-RNA levels in the GI tract and FRT of EFdA-treated BLT mice compared to untreated HIV-infected control mice. In addition, HIV-RNA was also significantly lower in the lymph nodes, liver, lung, spleen of EFdA-treated BLT mice compared to untreated HIV-infected control mice. Furthermore, EFdA treatment prevented the depletion of CD4+ T cells in the PB, mucosal tissues and lymphoid tissues.Our findings indicate that EFdA is highly effective in controlling viral replication and preserving CD4+ T cells in particular with high efficiency in the GI and FRT tract. Thus, EFdA represents a strong potential candidate for further development as a part of antiretroviral therapy regimens.

  9. Consolidating HIV testing in a public health laboratory for efficient and sustainable early infant diagnosis (EID) in Uganda.

    Science.gov (United States)

    Kiyaga, Charles; Sendagire, Hakim; Joseph, Eleanor; Grosz, Jeff; McConnell, Ian; Narayan, Vijay; Esiru, Godfrey; Elyanu, Peter; Akol, Zainab; Kirungi, Wilford; Musinguzi, Joshua; Opio, Alex

    2015-05-01

    Uganda introduced an HIV Early Infant Diagnosis (EID) program in 2006, and then worked to improve the laboratory, transportation, and clinical elements. Reported here are the activities involved in setting up a prospective analysis in which the Ministry of Health, with its NGO partners, determined it would be more effective and efficient to consolidate the initial eight-laboratory system for EID testing of HIV dried blood samples offered by two nongovernmental partners operating research facilities into a single well-equipped and staffed laboratory within the Ministry. A retrospective analysis confirmed that redesign reduced overhead cost per PCR test of HIV dried blood samples from US$22.20 to an average of $5. Along with the revamped system of sample collection, transportation, and result communication, Uganda has been able to vastly increase the HIV diagnosis of babies and engagement of them and their mothers in clinical care, including antiretroviral therapy. Uganda reduced turnaround times for results reporting to clinicians from more than a month in 2006 to just 2 weeks by 2014, even as samples tested increased dramatically. The next challenge is overcoming loss of babies and mothers to follow up.

  10. HIV-1 TAT protein enhances sensitization to methamphetamine by affecting dopaminergic function.

    Science.gov (United States)

    Kesby, James P; Najera, Julia A; Romoli, Benedetto; Fang, Yiding; Basova, Liana; Birmingham, Amanda; Marcondes, Maria Cecilia G; Dulcis, Davide; Semenova, Svetlana

    2017-10-01

    Methamphetamine abuse is common among humans with immunodeficiency virus (HIV). The HIV-1 regulatory protein TAT induces dysfunction of mesolimbic dopaminergic systems which may result in impaired reward processes and contribute to methamphetamine abuse. These studies investigated the impact of TAT expression on methamphetamine-induced locomotor sensitization, underlying changes in dopamine function and adenosine receptors in mesolimbic brain areas and neuroinflammation (microgliosis). Transgenic mice with doxycycline-induced TAT protein expression in the brain were tested for locomotor activity in response to repeated methamphetamine injections and methamphetamine challenge after a 7-day abstinence period. Dopamine function in the nucleus accumbens (Acb) was determined using high performance liquid chromatography. Expression of dopamine and/or adenosine A receptors (ADORA) in the Acb and caudate putamen (CPu) was assessed using RT-PCR and immunohistochemistry analyses. Microarrays with pathway analyses assessed dopamine and adenosine signaling in the CPu. Activity-dependent neurotransmitter switching of a reserve pool of non-dopaminergic neurons to a dopaminergic phenotype in the ventral tegmental area (VTA) was determined by immunohistochemistry and quantified with stereology. TAT expression enhanced methamphetamine-induced sensitization. TAT expression alone decreased striatal dopamine (D1, D2, D4, D5) and ADORA1A receptor expression, while increasing ADORA2A receptors expression. Moreover, TAT expression combined with methamphetamine exposure was associated with increased adenosine A receptors (ADORA1A) expression and increased recruitment of dopamine neurons in the VTA. TAT expression and methamphetamine exposure induced microglia activation with the largest effect after combined exposure. Our findings suggest that dopamine-adenosine receptor interactions and reserve pool neuronal recruitment may represent potential targets to develop new treatments for

  11. Efficiency enhancement of InGaN amber MQWs using nanopillar structures

    KAUST Repository

    Ou, Yiyu

    2017-09-09

    We have investigated the use of nanopillar structures on high indium content InGaN amber multiple quantum well (MQW) samples to enhance the emission efficiency. A significant emission enhancement was observed which can be attributed to the enhancement of internal quantum efficiency and light extraction efficiency. The size-dependent strain relaxation effect was characterized by photoluminescence, Raman spectroscopy and time-resolved photoluminescence measurements. In addition, the light extraction efficiency of different MQW samples was studied by finite-different time-domain simulations. Compared to the as-grown sample, the nanopillar amber MQW sample with a diameter of 300 nm has demonstrated an emission enhancement by a factor of 23.8.

  12. Flexible organic solar cells including efficiency enhancing grating structures

    DEFF Research Database (Denmark)

    Oliveira Hansen, Roana Melina de; Liu, Yinghui; Madsen, Morten

    2013-01-01

    In this work, a new method for the fabrication of organic solar cells containing functional light-trapping nanostructures on flexible substrates is presented. Polyimide is spin-coated on silicon support substrates, enabling standard micro- and nanotechnology fabrication techniques......, such as photolithography and electron-beam lithography, besides the steps required for the bulk-heterojunction organic solar cell fabrication. After the production steps, the solar cells on polyimide are peeled off the silicon support substrates, resulting in flexible devices containing nanostructures for light absorption...... enhancement. Since the solar cells avoid using brittle electrodes, the performance of the flexible devices is not affected by the peeling process. We have investigated three different nanostructured grating designs and conclude that gratings with a 500 nm pitch distance have the highest light...

  13. Efficient rewirings for enhancing synchronizability of dynamical networks

    Science.gov (United States)

    Rad, Ali Ajdari; Jalili, Mahdi; Hasler, Martin

    2008-09-01

    In this paper, we present an algorithm for optimizing synchronizability of complex dynamical networks. Starting with an undirected and unweighted network, we end up with an undirected and unweighted network with the same number of nodes and edges having enhanced synchronizability. To this end, based on some network properties, rewirings, i.e., eliminating an edge and creating a new edge elsewhere, are performed iteratively avoiding always self-loops and multiple edges between the same nodes. We show that the method is able to enhance the synchronizability of networks of any size and topological properties in a small number of steps that scales with the network size. For numerical simulations, an optimization algorithm based on simulated annealing is used. Also, the evolution of different topological properties of the network such as distribution of node degree, node and edge betweenness centrality is tracked with the iteration steps. We use networks such as scale-free, Strogatz-Watts and random to start with and we show that regardless of the initial network, the final optimized network becomes homogeneous. In other words, in the network with high synchronizability, parameters, such as, degree, shortest distance, node, and edge betweenness centralities are almost homogeneously distributed. Also, parameters, such as, maximum node and edge betweenness centralities are small for the rewired network. Although we take the eigenratio of the Laplacian as the target function for optimization, we show that it is also possible to choose other appropriate target functions exhibiting almost the same performance. Furthermore, we show that even if the network is optimized taking into account another interpretation of synchronizability, i.e., synchronization cost, the optimal network has the same synchronization properties. Indeed, in networks with optimized synchronizability, different interpretations of synchronizability coincide. The optimized networks are Ramanujan graphs

  14. Enhancing Efficiency of Perovskite Solar Cells via Surface Passivation with Graphene Oxide Interlayer.

    Science.gov (United States)

    Li, Hao; Tao, Leiming; Huang, Feihong; Sun, Qiang; Zhao, Xiaojuan; Han, Junbo; Shen, Yan; Wang, Mingkui

    2017-11-08

    Perovskite solar cells have been demonstrated as promising low-cost and highly efficient next-generation solar cells. Enhancing VOC by minimization the interfacial recombination kinetics can further improve device performance. In this work, we for the first time reported on surface passivation of perovskite layers with chemical modified graphene oxides, which act as efficient interlayer to reduce interfacial recombination and enhance hole extraction as well. Our modeling points out that the passivation effect mainly comes from the interaction between functional group (4-fluorophenyl) and under-coordinated Pb ions. The resulting perovskite solar cells achieved high efficient power conversion efficiency of 18.75% with enhanced high open circuit VOC of 1.11 V. Ultrafast spectroscopy, photovoltage/photocurrent transient decay, and electronic impedance spectroscopy characterizations reveal the effective passivation effect and the energy loss mechanism. This work sheds light on the importance of interfacial engineering on the surface of perovskite layers and provides possible ways to improve device efficiency.

  15. Enhancement in Photoelectrochemical Efficiency by Fabrication of BiVO4@MWCNT Nanocomposites

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2011-01-01

    Full Text Available An enormous enhancement in the photo-to-current conversion efficiency over the nanocomposite material composed by BiVO4 on the surface of MWCNTs, with respect to electrode of pure BiVO4, was observed. The heterojunction formed between MWCNTs and nano-BiVO4 is beneficial for the separation of photogenerated electrons and holes, resulting in more electrons that are able to transport efficiently to the surface and therefore enhance the photoefficiency.

  16. Changeover-time in psychosocial wellbeing of people living with HIV and people living close to them after an HIV stigma reduction and wellness enhancement community intervention.

    Science.gov (United States)

    Chidrawi, H Christa; Greeff, Minrie; Temane, Q Michael; Ellis, Suria

    2015-01-01

    HIV stigma continues to affect the psychosocial wellbeing of people living with HIV (PLWH) and people living close to them (PLC). Literature unequivocally holds the view that HIV stigma and psychosocial wellbeing interact with and have an impact on each other. This study, which is part of a larger research project funded by the South Africa Netherlands research Programme on Alternatives in Development (SANPAD), responds to the lack of interventions mitigating the impactful interaction of HIV stigma and psychosocial wellbeing and tests one such intervention. The research objectives were to test the changeover-time in the psychosocial wellbeing of PLWH and PLC in an urban and a rural setting, following a comprehensive community-based HIV stigma reduction and wellness enhancement intervention. An experimental quantitative single system research design with a pre- and four repetitive post-tests was used, conducting purposive voluntary sampling for PLWH (n = 18) and snowball sampling for PLC (n = 60). The average age of participants was 34 years old. The five measuring instruments used for both groups were the mental health continuum short-form scale, the patient health questionnaire, the satisfaction with life scale, the coping self-efficacy scale and the spirituality wellbeing scale. No significant differences were found between the urban-rural settings and data were pooled for analysis. The findings show that initial psychosocial wellbeing changes after the intervention were better sustained (over time) by the PLC than by the PLWH and seemed to be strengthened by interpersonal interaction. Recommendations included that the intervention should be re-utilised and that its tenets, content and activities be retained. A second intervention three to six months after the first should be included to achieve more sustainability and to add focused activities for the enhancement of psychosocial wellbeing. PLWH and PLC are to be encouraged to engage with innovative community

  17. Efficient and specific internal cleavage of a retroviral palindromic DNA sequence by tetrameric HIV-1 integrase.

    Directory of Open Access Journals (Sweden)

    Olivier Delelis

    Full Text Available BACKGROUND: HIV-1 integrase (IN catalyses the retroviral integration process, removing two nucleotides from each long terminal repeat and inserting the processed viral DNA into the target DNA. It is widely assumed that the strand transfer step has no sequence specificity. However, recently, it has been reported by several groups that integration sites display a preference for palindromic sequences, suggesting that a symmetry in the target DNA may stabilise the tetrameric organisation of IN in the synaptic complex. METHODOLOGY/PRINCIPAL FINDINGS: We assessed the ability of several palindrome-containing sequences to organise tetrameric IN and investigated the ability of IN to catalyse DNA cleavage at internal positions. Only one palindromic sequence was successfully cleaved by IN. Interestingly, this symmetrical sequence corresponded to the 2-LTR junction of retroviral DNA circles-a palindrome similar but not identical to the consensus sequence found at integration sites. This reaction depended strictly on the cognate retroviral sequence of IN and required a full-length wild-type IN. Furthermore, the oligomeric state of IN responsible for this cleavage differed from that involved in the 3'-processing reaction. Palindromic cleavage strictly required the tetrameric form, whereas 3'-processing was efficiently catalysed by a dimer. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that the restriction-like cleavage of palindromic sequences may be a general physiological activity of retroviral INs and that IN tetramerisation is strongly favoured by DNA symmetry, either at the target site for the concerted integration or when the DNA contains the 2-LTR junction in the case of the palindromic internal cleavage.

  18. Linearization and efficiency enhancement of power amplifiers using digital predistortion

    Energy Technology Data Exchange (ETDEWEB)

    Safari, Nima

    2008-07-01

    Today, demand of higher spectral efficiency forces wireless communication systems to employ non-constant envelope modulation schemes such as Quadrature Amplitude Modulations (QAM), Code Division Multiple Access (CDMA) and Orthogonal Frequency-Division Multiplexing (OFDM) schemes. These modulation techniques generate signals with wide range of envelope fluctuation. This property makes these schemes sensitive to nonlinear amplifications. Nonlinearities introduced by Power Amplifiers (PA) cause both a distortion of the signal and an increased out of band output spectrum, which leads to a rise in adjacent channel interference. Thus, in order to ensure a high spectral efficiency and to avoid spectral regrowth, a linearization technique is required. Among all the linearization techniques, basedband Digital Predistortion (DPD) is one of the commonly used linearization techniques, which is characterized by robust operation, low implementation cost and high accuracy. In the first chapter of this thesis, an introduction on the motivation and necessity of using PA linearization techniques is presented. Digital Predistortion as a popular linearization technique aims to improve the efficiency and linearity of RF power amplifiers. The scope of the thesis, the goals to be achieved and the contributions are also discussed in chapter one. Chapter two, mainly discusses sample-by-sample updating algorithm in Digital Predistorters to adaptively linearize the PA memoryless nonlinearities. Look-up Table (LUT) and polynomial approaches are studied and implemented in Hardware using a test-bed provided by Nera Research. The experimental results together with a discussion are then given. A new DPD algorithm based on block estimation is proposed in chapter three to avoid realtime signal processing, reduce the complexity and also avoid the bad performance during the slow adaptation of adaptive the Adjacent Channel Power Ratio (ACPR) and the Error Vector Magnitude (EVM) requirements. In

  19. TLR2-Modulating Lipoproteins of the Mycobacterium tuberculosis Complex Enhance the HIV Infectivity of CD4+ T Cells.

    Science.gov (United States)

    Skerry, Ciaran; Klinkenberg, Lee G; Page, Kathleen R; Karakousis, Petros C

    2016-01-01

    Co-infection with Mycobacterium tuberculosis accelerates progression from HIV to AIDS. Our previous studies showed that M. tuberculosis complex, unlike M. smegmatis, enhances TLR2-dependent susceptibility of CD4+ T cells to HIV. The M. tuberculosis complex produces multiple TLR2-stimulating lipoproteins, which are absent in M. smegmatis. M. tuberculosis production of mature lipoproteins and TLR2 stimulation is dependent on cleavage by lipoprotein signal peptidase A (LspA). In order to determine the role of potential TLR2-stimulating lipoproteins on mycobacterial-mediated HIV infectivity of CD4+ T cells, we generated M. smegmatis recombinant strains overexpressing genes encoding various M. bovis BCG lipoproteins, as well as a Mycobacterium bovis BCG strain deficient in LspA (ΔlspA). Exposure of human peripheral blood mononuclear cells (PBMC) to M. smegmatis strains overexpressing the BCG lipoproteins, LprF (p<0.01), LprH (p<0.05), LprI (p<0.05), LprP (p<0.001), LprQ (p<0.005), MPT83 (p<0.005), or PhoS1 (p<0.05), resulted in increased HIV infectivity of CD4+ T cells isolated from these PBMC. Conversely, infection of PBMC with ΔlspA reduced HIV infectivity of CD4+ T cells by 40% relative to BCG-infected cells (p<0.05). These results may have important implications for TB vaccination programs in areas with high mother-to-child HIV transmission.

  20. Enhanced activity of carbosilane dendrimers against HIV when combined with reverse transcriptase inhibitor drugs: searching for more potent microbicides

    Science.gov (United States)

    Vacas-Córdoba, Enrique; Galán, Marta; de la Mata, Francisco J; Gómez, Rafael; Pion, Marjorie; Muñoz-Fernández, M Ángeles

    2014-01-01

    Self-administered topical microbicides or oral preexposure prophylaxis could be very helpful tools for all risk groups to decrease the human immunodeficiency virus (HIV)-1 infection rates. Up until now, antiretrovirals (ARVs) have been the most advanced microbicide candidates. Nevertheless, the majority of clinical trials has failed in HIV-1 patients. Nanotechnology offers suitable approaches to develop novel antiviral agents. Thereby, new nanosystems, such as carbosilane dendrimers, have been shown to be safe and effective compounds against HIV with great potential as topical microbicides. In addition, because most of the attempts to develop effective topical microbicides were unsuccessful, combinatorial strategies could be a valid approach when designing new microbicides. We evaluated various combinations of anionic carbosilane dendrimers with sulfated (G3-S16) and naphthyl sulfonated (G2-NF16) ended groups with different ARVs against HIV-1 infection. The G3-S16 and G2-NF16 dendrimers showed a synergistic or additive activity profile with zidovudine, efavirenz, and tenofovir in the majority of the combinations tested against the X4 and R5 tropic HIV-1 in cell lines, as well as in human primary cells. Therefore, the combination of ARVs and polyanionic carbosilane dendrimers enhances the antiviral potency of the individual compounds, and our findings support further clinical research on combinational approaches as potential microbicides to block the sexual transmission of HIV-1. PMID:25114528

  1. Elimination of Mother-To-Child Transmission of HIV Infection: The Drug Resource Enhancement against AIDS and Malnutrition Model

    Directory of Open Access Journals (Sweden)

    Giuseppe Liotta

    2015-10-01

    Full Text Available The Drug Resource Enhancement against AIDS and Malnutrition Program (DREAM gathered professionals in the field of Elimination of HIV-Mother-To-Child Transmission (EMTCT in Maputo in 2013 to discuss obstacles and solutions for the elimination of HIV vertical transmission in sub-Saharan Africa. During this workshop, the benefits of administrating combined antiretroviral therapy (cART to HIV positive women from pregnancy throughout breastfeeding were reviewed. cART is capable of reducing vertical transmission to less than 5% at 24 months of age, as well as maternal mortality and infant mortality in both HIV infected and exposed populations to levels similar to those of uninfected individuals. The challenge for programs targeting eMTCT in developing countries is retention in care and treatment adherence. Both are intrinsically related to the model of care. The drop-out from eMTCT programs before cART initiation ranges from 33%–88% while retention rates at 18–24 months are less than 50%. Comprehensive strategies including peer-to-peer education, social support and laboratory monitoring can reduce refusals to less than 5% and attain retention rates approaching 90%. Several components of the model of care for reduction of HIV-1 MTCT are feasible and implementable in scale-up strategies. A review of this model of care for HIV eMTCT is provided.

  2. HIV-1 nucleocapsid protein localizes efficiently to the nucleus and nucleolus

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Kyung Lee; Lee, Sun Hee; Lee, Eun Soo; You, Ji Chang, E-mail: jiyou@catholic.ac.kr

    2016-05-15

    The HIV-1 nucleocapsid (NC) is an essential viral protein containing two highly conserved retroviral-type zinc finger (ZF) motifs, which functions in multiple stages of the HIV-1 life cycle. Although a number of functions for NC either in its mature form or as a domain of Gag have been revealed, little is known about the intracellular localization of NC and, moreover, its role in Gag protein trafficking. Here, we have investigated various forms of HIV-1 NC protein for its cellular localization and found that the NC has a strong nuclear and nucleolar localization activity. The linker region, composed of a stretch of basic amino acids between the two ZF motifs, was necessary and sufficient for the activity. - Highlights: • HIV-1 NC possess a NLS and leads to nuclear and nucleolus localization. • Mutations in basic residues between two ZFs in NC decrease the nucleus localization. • ZFs of NC affect cytoplasmic organelles localization rather than nucleus localization.

  3. Energy efficient heterogeneous DEEC protocol for enhancing lifetime in WSNs

    Directory of Open Access Journals (Sweden)

    Samayveer Singh

    2017-02-01

    Full Text Available In this paper, we propose a 3-level heterogeneous network model for WSNs to enhance the network lifetime, which is characterized by a single parameter. Depending upon the value of the model parameter, it can describe 1-level, 2-level, and 3-level heterogeneity. Our heterogeneous network model also helps to select cluster heads and their respective cluster members by using weighted election probability and threshold function. We compute the network lifetime by implementing DEEC protocol for our network model. The DEEC implementation for the existing 1-level, 2-level, and 3-level heterogeneous network models are denoted as DEEC-1, DEEC-2, and DEEC-3, respectively, and for our proposed 3-level heterogeneous network model, the DEEC implementations are denoted as hetDEEC-1, hetDEEC-2, and hetDEEC-3, respectively. The network lifetime in DEEC-3 and hetDEEC-3 increases by 154.17% and 182.67%, respectively by increasing the total network energy 100% with respect to the original DEEC.

  4. Stacked microbial desalination cells to enhance water desalination efficiency.

    Science.gov (United States)

    Chen, Xi; Xia, Xue; Liang, Peng; Cao, Xiaoxin; Sun, Haotian; Huang, Xia

    2011-03-15

    Microbial desalination cell (MDC) is a new method to obtain clean water from brackish water using electricity generated from organic matters by exoelectrogenic bacteria. Anions and cations, derived from salt solution filled in the desalination chamber between the anode and cathode, move to the anode and cathode chambers under the force of electrical field, respectively. On the basis of the primitive single-desalination-chambered MDC, stacked microbial desalination cells (SMDCs) were developed in order to promote the desalination rate in the present study. The effects of desalination chamber number and external resistance were investigated. Results showed that a remarkable increase in the total desalination rate (TDR) could be obtained by means of increasing the desalination cell number and reducing the external resistance, which caused the charge transfer efficiency increased since the SMDCs enabled more pairs of ions separated while one electron passed through the external circuit. The maximum TDR of 0.0252 g/h was obtained using a two-desalination-chambered SMDC with an external resistance of 10 Ω, which was 1.4 times that of single-desalination-chambered MDC. SMDCs proved to be an effective approach to increase the total water desalination rate if provided a proper desalination chamber number and external resistance.

  5. Enhancing efficacy and mucosa-tropic distribution of an oral HIV-PsV DNA vaccine in animal models.

    Science.gov (United States)

    Fu, Jie; Bian, Guangxing; Zhao, Bijun; Dong, Zengxiang; Sun, Xiao; Chen, Fang; Ou, Lun; Song, Haifeng

    2009-12-01

    A strategy combined the oral delivery route and bovine papillomavirus (BPV) pseudovirus (PsV)-based human immunodeficiency virus (HIV) DNA vaccine, which has been proven to enhance the mucosal immunization compared with the systemic immunization and in general does not induce effective mucosal immune responses. In this study, the immune responses against the BPV expressing HIV gp41 epitopes (ELDKWA, NWFDIT) after oral administration in Cynomolgus monkeys (Macaca fascicularis) were assessed, and the biodistribution of plasmid DNA encapsulated in the papillomavirus-like particles (VLPs) were evaluated in murine models. Results showed that oral immunization with the HIV-PsV DNA vaccine in monkey generated p24 and gp41 epitopes-specific serum IgG. Importantly, these induced antibodies had been shown to neutralize HIV-1 primary strain. In addition, the advantage of VLPs as vehicles delivering genes had been first revealed in biodistribution results. Therefore, orally administered HIV-PsV DNA vaccine was well-tolerated, enhanced the mucosa targeting property of the plasmid DNA, and reduced the nontargeting distribution, which indicate that it would reduce stress associated with systemic vaccination.

  6. Efficiency enhancement of liquid crystal projection displays using light recycle technology

    Science.gov (United States)

    Wang, Y.

    2002-01-01

    A new technology developed at JPL using low absorption color filters with polarization and color recycle system, is able to enhance efficiency of a single panel liquid crytal display (LCD) projector to the same efficiency of a 3 panel LCD projector.

  7. Curcumin-loaded apotransferrin nanoparticles provide efficient cellular uptake and effectively inhibit HIV-1 replication in vitro.

    Directory of Open Access Journals (Sweden)

    Upendhar Gandapu

    Full Text Available Curcumin (diferuloylmethane shows significant activity across a wide spectrum of conditions, but its usefulness is rather limited because of its low bioavailability. Use of nanoparticle formulations to enhance curcumin bioavailability is an emerging area of research.In the present study, curcumin-loaded apotransferrin nanoparticles (nano-curcumin prepared by sol-oil chemistry and were characterized by electron and atomic force microscopy. Confocal studies and fluorimetric analysis revealed that these particles enter T cells through transferrin-mediated endocytosis. Nano-curcumin releases significant quantities of drug gradually over a fairly long period, ∼50% of curcumin still remaining at 6 h of time. In contrast, intracellular soluble curcumin (sol-curcumin reaches a maximum at 2 h followed by its complete elimination by 4 h. While sol-curcumin (GI(50 = 15.6 µM is twice more toxic than nano-curcumin (GI(50 = 32.5 µM, nano-curcumin (IC(50<1.75 µM shows a higher anti-HIV activity compared to sol-curcumin (IC(50 = 5.1 µM. Studies in vitro showed that nano-curcumin prominently inhibited the HIV-1 induced expression of Topo II α, IL-1β and COX-2, an effect not seen with sol-curcumin. Nano-curcumin did not affect the expression of Topoisomerase II β and TNF α. This point out that nano-curcumin affects the HIV-1 induced inflammatory responses through pathways downstream or independent of TNF α. Furthermore, nano-curcumin completely blocks the synthesis of viral cDNA in the gag region suggesting that the nano-curcumin mediated inhibition of HIV-1 replication is targeted to viral cDNA synthesis.Curcumin-loaded apotransferrin nanoparticles are highly efficacious inhibitors of HIV-1 replication in vitro and promise a high potential for clinical usefulness.

  8. HIV-1 efficient entry in inner foreskin is mediated by elevated CCL5/RANTES that recruits T cells and fuels conjugate formation with Langerhans cells.

    Directory of Open Access Journals (Sweden)

    Zhicheng Zhou

    2011-06-01

    Full Text Available Male circumcision reduces acquisition of HIV-1 by 60%. Hence, the foreskin is an HIV-1 entry portal during sexual transmission. We recently reported that efficient HIV-1 transmission occurs following 1 h of polarized exposure of the inner, but not outer, foreskin to HIV-1-infected cells, but not to cell-free virus. At this early time point, Langerhans cells (LCs and T-cells within the inner foreskin epidermis are the first cells targeted by the virus. To gain in-depth insight into the molecular mechanisms governing inner foreskin HIV-1 entry, foreskin explants were inoculated with HIV-1-infeceted cells for 4 h. The chemokine/cytokine milieu secreted by the foreskin tissue, and resulting modifications in density and spatial distribution of T-cells and LCs, were then investigated. Our studies show that in the inner foreskin, inoculation with HIV-1-infected cells induces increased CCL5/RANTES (1.63-fold and decreased CCL20/MIP-3-alpha (0.62-fold secretion. Elevated CCL5/RANTES mediates recruitment of T-cells from the dermis into the epidermis, which is blocked by a neutralizing CCL5/RANTES Ab. In parallel, HIV-1-infected cells mediate a bi-phasic modification in the spatial distribution of epidermal LCs: attraction to the apical surface at 1 h, followed by migration back towards the basement membrane later on at 4 h, in correlation with reduced CCL20/MIP-3-alpha at this time point. T-cell recruitment fuels the continuous formation of LC-T-cell conjugates, permitting the transfer of HIV-1 captured by LCs. Together, these results reveal that HIV-1 induces a dynamic process of immune cells relocation in the inner foreskin that is associated with specific chemokines secretion, which favors efficient HIV-1 entry at this site.

  9. HIV-1 Efficient Entry in Inner Foreskin Is Mediated by Elevated CCL5/RANTES that Recruits T Cells and Fuels Conjugate Formation with Langerhans Cells

    Science.gov (United States)

    Zhou, Zhicheng; Barry de Longchamps, Nicolas; Schmitt, Alain; Zerbib, Marc; Vacher-Lavenu, Marie-Cécile; Bomsel, Morgane; Ganor, Yonatan

    2011-01-01

    Male circumcision reduces acquisition of HIV-1 by 60%. Hence, the foreskin is an HIV-1 entry portal during sexual transmission. We recently reported that efficient HIV-1 transmission occurs following 1 h of polarized exposure of the inner, but not outer, foreskin to HIV-1-infected cells, but not to cell-free virus. At this early time point, Langerhans cells (LCs) and T-cells within the inner foreskin epidermis are the first cells targeted by the virus. To gain in-depth insight into the molecular mechanisms governing inner foreskin HIV-1 entry, foreskin explants were inoculated with HIV-1-infeceted cells for 4 h. The chemokine/cytokine milieu secreted by the foreskin tissue, and resulting modifications in density and spatial distribution of T-cells and LCs, were then investigated. Our studies show that in the inner foreskin, inoculation with HIV-1-infected cells induces increased CCL5/RANTES (1.63-fold) and decreased CCL20/MIP-3-alpha (0.62-fold) secretion. Elevated CCL5/RANTES mediates recruitment of T-cells from the dermis into the epidermis, which is blocked by a neutralizing CCL5/RANTES Ab. In parallel, HIV-1-infected cells mediate a bi-phasic modification in the spatial distribution of epidermal LCs: attraction to the apical surface at 1 h, followed by migration back towards the basement membrane later on at 4 h, in correlation with reduced CCL20/MIP-3-alpha at this time point. T-cell recruitment fuels the continuous formation of LC-T-cell conjugates, permitting the transfer of HIV-1 captured by LCs. Together, these results reveal that HIV-1 induces a dynamic process of immune cells relocation in the inner foreskin that is associated with specific chemokines secretion, which favors efficient HIV-1 entry at this site. PMID:21738469

  10. Operational Efficiency And Customer Satisfaction of Restaurants: Basis For Business Operation Enhancement

    OpenAIRE

    Annie Gay Barlan-Espino

    2017-01-01

    Restaurants’ primary objective is to provide comfort and satisfaction to guest without compromising the operational efficiency of the business. This research aimed to determine the operational efficiency and customer satisfaction of restaurants as a basis for business operation enhancement. Specifically to determine the operational efficiency of the restaurant in terms of kitchen operations and dining operations and the level of customer satisfaction of the restaurant business in ...

  11. Enhancing Energy Efficiency of Wireless Sensor Network through the Design of Energy Efficient Routing Protocol

    Directory of Open Access Journals (Sweden)

    Noor Zaman

    2016-01-01

    Full Text Available Wireless Sensor Network (WSN is known to be a highly resource constrained class of network where energy consumption is one of the prime concerns. In this research, a cross layer design methodology was adopted to design an energy efficient routing protocol entitled “Position Responsive Routing Protocol” (PRRP. PRRP is designed to minimize energy consumed in each node by (1 reducing the amount of time in which a sensor node is in an idle listening state and (2 reducing the average communication distance over the network. The performance of the proposed PRRP was critically evaluated in the context of network lifetime, throughput, and energy consumption of the network per individual basis and per data packet basis. The research results were analyzed and benchmarked against the well-known LEACH and CELRP protocols. The outcomes show a significant improvement in the WSN in terms of energy efficiency and the overall performance of WSN.

  12. Enhancing Photon Utilization Efficiency for Astaxanthin Production from Haematococcus lacustris Using a Split-Column Photobioreactor.

    Science.gov (United States)

    Kim, Z-Hun; Park, Hanwool; Lee, Ho-Sang; Lee, Choul-Gyun

    2016-07-28

    A split-column photobioreactor (SC-PBR), consisting of two bubble columns with different sizes, was developed to enhance the photon utilization efficiency in an astaxanthin production process from Haematococcus lacustris. Among the two columns, only the smaller column of SC-PBR was illuminated. Astaxanthin productivities and photon efficiencies of the SC-PBRs were compared with a standard bubble-column PBR (BC-PBR). Astaxanthin productivity of SC-PBR was improved by 28%, and the photon utilization efficiencies were 28-366% higher than the original BC-PBR. The results clearly show that the effective light regime of SC-PBR could enhance the production of astaxanthin.

  13. Decreased chronic morbidity but elevated HIV associated cytokine levels in HIV-infected older adults receiving HIV treatment: benefit of enhanced access to care?

    Directory of Open Access Journals (Sweden)

    Portia C Mutevedzi

    Full Text Available The association of HIV with chronic morbidity and inflammatory markers (cytokines in older adults (50+years is potentially relevant for clinical care, but data from African populations is scarce.To examine levels of chronic morbidity by HIV and ART status in older adults (50+years and subsequent associations with selected pro-inflammatory cytokines and body mass index.Ordinary, ordered and generalized ordered logistic regression techniques were employed to compare chronic morbidity (heart disease (angina, arthritis, stroke, hypertension, asthma and diabetes and cytokines (Interleukins-1 and -6, C-Reactive Protein and Tumor Necrosis Factor-alpha by HIV and ART status on a cross-sectional random sample of 422 older adults nested within a defined rural South African population based demographic surveillance.Using a composite measure of all morbidities, controlling for age, gender, BMI, smoking and wealth quintile, HIV-infected individuals on ART had 51% decreased odds (95% CI:0.26-0.92 of current morbidity compared to HIV-uninfected. In adjusted regression, compared to HIV-uninfected, the proportional odds (aPOR of having elevated inflammation markers of IL6 (>1.56 pg/mL was nearly doubled in HIV-infected individuals on (aPOR 1.84; 95%CI: 1.05-3.21 and not on (aPOR 1.94; 95%CI: 1.11-3.41 ART. Compared to HIV-uninfected, HIV-infected individuals on ART had >twice partial proportional odds (apPOR=2.30;p=0.004 of having non-clinically significant raised hsCRP levels(>1 ug/mL; ART-naïve HIV-infected individuals had >double apPOR of having hsCRP levels indicative of increased heart disease risk(>3.9 ug/mL;p=0.008.Although HIV status was associated with increased inflammatory markers, our results highlight reduced morbidity in those receiving ART and underscore the need of pro-actively extending these services to HIV-uninfected older adults, beyond mere provision at fixed clinics. Providing health services through regular community chronic disease

  14. Influence of socio-demographic factors on distances travelled to access HIV services: enhanced surveillance of HIV patients in north west England

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    Tocque Karen

    2009-03-01

    Full Text Available Abstract Background Patient choice and access to health care is compromised by many barriers including travel distance. Individuals with the human immunodeficiency virus (HIV can seek free specialist care in Britain, without a referral, providing flexible access to care services. Willingness to travel beyond local services for preferred care has funding and service implications. Data from an enhanced HIV surveillance system were used to explore geodemographic and clinical factors associated with accessing treatment services. Methods We extracted data on the location, type and frequency of care services utilized by HIV positive persons (n = 3983 accessing treatment in north west England between January 1st 2005 and June 30th 2006. Individuals were allocated a deprivation score and grouped by urban/rural residence, and distance to care services was calculated. Analysis identified independent predictors of distance travelled (general linear modelling and, for those bypassing their nearest clinic, the probability of accessing a specialist service (logistic regression, SPSS ver 14. Inter-relationships between variables and distance travelled were visualised using detrended correspondence analysis (PC-ORD ver 4.1. Results HIV infected persons travelled an average of 4.8 km (95% confidence intervals (CI 4.6–4.9 per trip and had on average 6 visits (95% CI 5.9–6.2 annually for care. Longer trips were made by males (4.8 km vs 4.5 km, white people (6.2 km, the young (>15 years, 6.8 km and elderly (60+ years, 6.3 km, those on multiple therapy (5.3 km vs 4.0 km, and the more affluent living in rural areas (16.1 km, P Conclusion Distance travelled, and type of HIV services used, were associated with socioeconomic status, even after accounting for ethnicity, route of infection and age. Thus despite offering an 'equitable' service, travel costs may advantage those with higher income.

  15. Underwater giant enhancement of broadband diffraction efficiency of surface diffraction gratings fabricated by femtosecond laser

    Science.gov (United States)

    Zhang, Fan; Wang, Cong; Yin, Kai; Dong, Xinran; Song, Yuxin; Tian, Yaxiang; Duan, Ji'an

    2017-06-01

    In this study, a simple approach is proposed to improve the diffraction efficiency of surface diffraction gratings on fused silica fabricated by femtosecond laser. Effects of grating period, pulse energy, scanning speed and wavelength on the total diffraction efficiency are also investigated. In addition, the mechanism of the diffraction efficiency's giant enhancement is discussed by finite difference time domain (FDTD) and optical phase shift structure calculation. It is revealed that: (1) Compared with the diffraction efficiency obtained in air, the underwater image via diffraction grating is clearer than that in air and diffraction pattern in water is much brighter; (2) The diffraction efficiency increases with an increase in wavelength and scanning speed, whereas it decreases while the laser pulse energy is high; and (3) This giant enhancement is attributed to the degree of Mie scattering and refraction, which is effectively reduced for the existence of water.

  16. Enhanced normalisation of CD4/CD8 ratio with early antiretroviral therapy in primary HIV infection

    Directory of Open Access Journals (Sweden)

    John Thornhill

    2014-11-01

    association between normal CD4/CD8 ratio and being virally suppressed (<400 copies HIV RNA/ml p<0.001. CD4 count normalization was also significantly more likely for those initiating early (HR 5.00, 95% CI 1.52 – 16.41, p=0.008. Conclusions: The likelihood of achieving normalization of CD4/CD8 ratios was increased if ART was initiated within six months of PHI. Higher CD4/CD8 ratio may reflect a more “normal” immune phenotype conferring enhanced prognosis and predict post-treatment control.

  17. Energy efficient low-noise neural recording amplifier with enhanced noise efficiency factor.

    Science.gov (United States)

    Majidzadeh, V; Schmid, A; Leblebici, Y

    2011-06-01

    This paper presents a neural recording amplifier array suitable for large-scale integration with multielectrode arrays in very low-power microelectronic cortical implants. The proposed amplifier is one of the most energy-efficient structures reported to date, which theoretically achieves an effective noise efficiency factor (NEF) smaller than the limit that can be achieved by any existing amplifier topology, which utilizes a differential pair input stage. The proposed architecture, which is referred to as a partial operational transconductance amplifier sharing architecture, results in a significant reduction of power dissipation as well as silicon area, in addition to the very low NEF. The effect of mismatch on crosstalk between channels and the tradeoff between noise and crosstalk are theoretically analyzed. Moreover, a mathematical model of the nonlinearity of the amplifier is derived, and its accuracy is confirmed by simulations and measurements. For an array of four neural amplifiers, measurement results show a midband gain of 39.4 dB and a -3-dB bandwidth ranging from 10 Hz to 7.2 kHz. The input-referred noise integrated from 10 Hz to 100 kHz is measured at 3.5 μVrms and the power consumption is 7.92 μW from a 1.8-V supply, which corresponds to NEF = 3.35. The worst-case crosstalk and common-mode rejection ratio within the desired bandwidth are - 43.5 dB and 70.1 dB, respectively, and the active silicon area of each amplifier is 256 μm × 256 μm in 0.18-μm complementary metal-oxide semiconductor technology.

  18. Antibodies raised to short synthetic peptides with sequences derived from HIV-1 SF2 gp120 can both neutralize and enhance HIV-1 SF13: a later variant isolated from the same host.

    Science.gov (United States)

    Davis, D; Trischmann, H; Stephens, D M; Lachmann, P J

    2001-07-01

    HIV-1 SF13 emerged in a patient with immunity to HIV-1 SF2. This study determined the effect of antibodies raised to HIV-1 SF2 on the replication of the later variant. Antisera in rats were raised previously to a complete set of overlapping, synthetic 15mer peptides following the sequence of HIV-1 SF2 gp120. These sera have now been used in neutralization and enhancement assays against viruses derived from molecular clones of both variants. The sets of peptides inducing neutralizing antibodies to the two variants overlap. Antibodies to the third variable region of HIV-1 SF2 only neutralize the homologous virus whereas those to the second and fourth variable regions neutralize both variants. In contrast, the sets of major epitopes involved in enhancement do not overlap. Epitopes for both variants form two clusters when superimposed on the conformation of the conserved regions. To determine if antibodies with the potential to enhance or neutralize HIV-1 SF2 change over time in infected individuals sera from chimpanzees were used because no material was still available from the original patient. Antibodies to HIV-1 SF2 neutralizing epitopes and HIV-1 SF13 enhancing epitopes were present in the circulation of chimpanzees infected with HIV-1 SF2. Once antibodies to the neutralizing epitopes were induced they persisted whereas antibodies to the enhancing epitopes varied with time after infection. Conditions may therefore exist within individual hosts where not only neutralizing but also enhancing antibodies have the potential to contribute to the selection pressure operating on the circulating population of polymorphic variants. Copyright 2001 Wiley-Liss, Inc.

  19. Heat Shock-Enhanced Conjugation Efficiency in Standard Campylobacter jejuni Strains.

    Science.gov (United States)

    Zeng, Ximin; Ardeshna, Devarshi; Lin, Jun

    2015-07-01

    Campylobacter jejuni, the leading bacterial cause of human gastroenteritis in the United States, displays significant strain diversity due to horizontal gene transfer. Conjugation is an important horizontal gene transfer mechanism contributing to the evolution of bacterial pathogenesis and antimicrobial resistance. It has been observed that heat shock could increase transformation efficiency in some bacteria. In this study, the effect of heat shock on C. jejuni conjugation efficiency and the underlying mechanisms were examined. With a modified Escherichia coli donor strain, different C. jejuni recipient strains displayed significant variation in conjugation efficiency ranging from 6.2 × 10(-8) to 6.0 × 10(-3) CFU per recipient cell. Despite reduced viability, heat shock of standard C. jejuni NCTC 11168 and 81-176 strains (e.g., 48 to 54°C for 30 to 60 min) could dramatically enhance C. jejuni conjugation efficiency up to 1,000-fold. The phenotype of the heat shock-enhanced conjugation in C. jejuni recipient cells could be sustained for at least 9 h. Filtered supernatant from the heat shock-treated C. jejuni cells could not enhance conjugation efficiency, which suggests that the enhanced conjugation efficiency is independent of secreted substances. Mutagenesis analysis indicated that the clustered regularly interspaced short palindromic repeats system and the selected restriction-modification systems (Cj0030/Cj0031, Cj0139/Cj0140, Cj0690c, and HsdR) were dispensable for heat shock-enhanced conjugation in C. jejuni. Taking all results together, this study demonstrated a heat shock-enhanced conjugation efficiency in standard C. jejuni strains, leading to an optimized conjugation protocol for molecular manipulation of this organism. The findings from this study also represent a significant step toward elucidation of the molecular mechanism of conjugative gene transfer in C. jejuni. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  20. 78 FR 45246 - Office of Clinical and Preventive Services National HIV Program: Enhanced HIV/AIDS Screening and...

    Science.gov (United States)

    2013-07-26

    ..., reduce stigma, make HIV testing routine, and improve engagement in care. Emphasis should be placed on... meant to address and reduce stigma. 3. Reaching a wide range of persons including diverse age and sex... care, or early childhood development services are provided to children. This is consistent with the HHS...

  1. A novel strategy for inducing enhanced mucosal HIV-1 antibody responses in an anti-inflammatory environment.

    Directory of Open Access Journals (Sweden)

    Frank Wegmann

    2011-01-01

    Full Text Available Prophylactic vaccination against HIV-1 sexual transmission will probably require antibody elicitation at genital mucosal surfaces. However, HIV-1 envelope glycoprotein (Env-based antigens are weakly immunogenic, particularly when applied mucosally. The polyanion PRO 2000 is safe for human vaginal application, and thus may represent a potential formulating agent for vaginal delivery of experimental vaccine immunogens. Based upon its biochemical properties, we hypothesized that PRO 2000 might enhance mucosal immunogenicity of HIV-1 envelope glycoprotein (Env-based antigens, promoting local and systemic immune responses. Vaginal immunization with Env-PRO 2000 resulted in significantly increased titres of Env-specific mucosal IgA and IgG in mice and rabbits, respectively, compared to Env alone, revealing modest but significant mucosal adjuvant activity for PRO 2000. In vitro, PRO 2000 associated with Env, protecting the glycoprotein from proteolytic degradation in human vaginal lavage. Unexpectedly, PRO 2000 antagonized TLR4 activation, suppressing local production of inflammatory cytokines. Since inflammation-mediated recruitment of viral target cells is a major risk factor in HIV-1 transmission, the immune modulatory and anti-inflammatory activities of PRO 2000 combined with its intravaginal safety profile suggests promise as an HIV-1 mucosal vaccine formulating agent.

  2. The MSHA strain of Pseudomonas aeruginosa activated TLR pathway and enhanced HIV-1 DNA vaccine immunoreactivity.

    Directory of Open Access Journals (Sweden)

    Jue Hou

    Full Text Available The mannose-sensitive hemagglutination pilus strain of Pseudomonas aeruginosa (PA-MSHA has been shown to trigger naïve immune responses through the activation of monocytes, macrophages, natural killer cells (NK cells and antigen presenting cells (APCs. Based on the hypothesis that PA-MSHA activates natural immunity through the Toll-like receptor (TLR pathway, we scanned several critical TLR pathway molecules in mouse splenocytes using high-throughput real-time QRT-PCR and co-stimulatory molecule in bone marrow-derived dendritic cells (BMDCs following in vitro stimulation by PA-MSHA. PA-MSHA enabled activation of the TLR pathway mediated by NF-κB and JNK signaling in splenocytes, and the co-stimulatory molecule CD86 was up-regulated in BMDCs. We then assessed the adjuvant effect of PA-MSHA for HIV-1 DNA vaccines. In comparison to DNA inoculation alone, co-inoculation with low dosage of PA-MSHA enhanced specific immunoreactivity against HIV-1 Env in both cellular and humoral responses, and promoted antibody avidity maturation. However, high doses of adjuvant resulted in an immunosuppressive effect; a two- or three-inoculation regimen yielded low antibody responses and the two-inoculation regimen exhibited only a slight cellular immunity response. To our knowledge, this is the first report demonstrating the utility of PA-MSHA as an adjuvant to a DNA vaccine. Further research is needed to investigate the exact mechanisms through which PA-MSHA achieves its adjuvant effects on innate immune responses, especially on dendritic cells.

  3. A candidate HIV/AIDS vaccine (MVA-B lacking vaccinia virus gene C6L enhances memory HIV-1-specific T-cell responses.

    Directory of Open Access Journals (Sweden)

    Juan García-Arriaza

    Full Text Available The vaccinia virus (VACV C6 protein has sequence similarities with the poxvirus family Pox_A46, involved in regulation of host immune responses, but its role is unknown. Here, we have characterized the C6 protein and its effects in virus replication, innate immune sensing and immunogenicity in vivo. C6 is a 18.2 kDa protein, which is expressed early during virus infection and localizes to the cytoplasm of infected cells. Deletion of the C6L gene from the poxvirus vector MVA-B expressing HIV-1 Env, Gag, Pol and Nef antigens from clade B (MVA-B ΔC6L had no effect on virus growth kinetics; therefore C6 protein is not essential for virus replication. The innate immune signals elicited by MVA-B ΔC6L in human macrophages and monocyte-derived dendritic cells (moDCs are characterized by the up-regulation of the expression of IFN-β and IFN-α/β-inducible genes. In a DNA prime/MVA boost immunization protocol in mice, flow cytometry analysis revealed that MVA-B ΔC6L enhanced the magnitude and polyfunctionality of the HIV-1-specific CD4+ and CD8+ T-cell memory immune responses, with most of the HIV-1 responses mediated by the CD8+ T-cell compartment with an effector phenotype. Significantly, while MVA-B induced preferentially Env- and Gag-specific CD8+ T-cell responses, MVA-B ΔC6L induced more Gag-Pol-Nef-specific CD8+ T-cell responses. Furthermore, MVA-B ΔC6L enhanced the levels of antibodies against Env in comparison with MVA-B. These findings revealed that C6 can be considered as an immunomodulator and that deleting C6L gene in MVA-B confers an immunological benefit by enhancing IFN-β-dependent responses and increasing the magnitude and quality of the T-cell memory immune responses to HIV-1 antigens. Our observations are relevant for the improvement of MVA vectors as HIV-1 vaccines.

  4. ENHANCING THE EFFICIENCY OF AZO-BASED DYE SENSITIZED SOLAR CELLS BY SURFACE TREATMENTS

    Directory of Open Access Journals (Sweden)

    JEANINA LUNGU

    2015-05-01

    Full Text Available We studied the conductive glass and/or the semiconductor surface treatments with aluminum ions as a technique to enhance the characteristics of dye sensitized solar cells (DSSCs based on Al-doped ZnO. The aluminum ions were deposited on the surfaces using aluminum isopropoxide as precursor, by an easy and efficient method. We measured the characteristics of the dye sensitized solar cells based on pre- and/or post-treated electrodes. Our study showed a clear enhancement of cells efficiencies for the DSSCs based on Al(III pre-treated electrodes (i.e. a percentage increase of almost 18 % and also a smaller improvement in the efficiencies of DSSCs based on Al(III post-treated photoelectrodes (i.e. a percentage increase of almost 10 %, giving a overall enhance of about 21 % reported to the untreated photoelectrode based DSSC.

  5. Comparative effectiveness of a faith-based HIV intervention for African American women: importance of enhancing religious social capital.

    Science.gov (United States)

    Wingood, Gina M; Robinson, LaShun R; Braxton, Nikia D; Er, Deja L; Conner, Anita C; Renfro, Tiffaney L; Rubtsova, Anna A; Hardin, James W; Diclemente, Ralph J

    2013-12-01

    We assessed the effectiveness of P4 for Women, a faith-based HIV intervention. We used a 2-arm comparative effectiveness trial involving 134 African American women aged 18 to 34 years to compare the effectiveness of the Centers for Disease Control and Prevention-defined evidence-based Sisters Informing Sisters about Topics on AIDS (SISTA) HIV intervention with P4 for Women, an adapted faith-based version of SISTA. Participants were recruited from a large black church in Atlanta, Georgia, and completed assessments at baseline and follow-up. Both SISTA and P4 for Women had statistically significant effects on this study's primary outcome-consistent condom use in the past 90 days-as well as other sexual behaviors. However, P4 for Women also had statistically significant effects on the number of weeks women were abstinent, on all psychosocial mediators, and most noteworthy, on all measures of religious social capital. Results were achieved by enhancing structural social capital through ministry participation, religious values and norms, linking trust and by reducing negative religious coping. High intervention attendance may indicate the feasibility of conducting faith-based HIV prevention research for African American women. P4 for Women enhanced abstinence and safer sex practices as well as religious social capital, and was more acceptable than SISTA. Such efforts may assist faith leaders in responding to the HIV epidemic in African American women.

  6. Post-transcriptional m6A editing of HIV-1 mRNAs enhances viral gene expression

    Science.gov (United States)

    Kennedy, Edward M.; Bogerd, Hal P.; Kornepati, Anand V. R.; Kang, Dong; Ghoshal, Delta; Marshall, Joy B.; Poling, Brigid C.; Tsai, Kevin; Gokhale, Nandan S.; Horner, Stacy M.; Cullen, Bryan R.

    2016-01-01

    Summary Covalent addition of a methyl group to the adenosine N6 (m6A) is an evolutionarily conserved and common RNA modification that is thought to modulate several aspects of RNA metabolism. While the presence of multiple m6A editing sites on diverse viral RNAs was reported starting almost 40 years ago, how m6A editing affects virus replication has remained unclear. Here, we used photo-crosslinking-assisted m6A sequencing techniques to precisely map several m6A editing sites on the HIV-1 genome and report that they cluster in the HIV-1 3’ untranslated region (3'UTR). Viral 3'UTR m6A sites or analogous cellular m6A sites strongly enhanced mRNA expression in cis by recruiting the cellular YTHDF m6A “reader” proteins. Reducing YTHDF expression inhibited, while YTHDF overexpression enhanced, HIV-1 protein and RNA expression, and virus replication in CD4+ T cells. These data identify m6A editing, and the resultant recruitment of YTHDF proteins, as major positive regulators of HIV-1 mRNA expression. PMID:27117054

  7. BCN Checkpoint, a community-based centre for men who have sex with men in Barcelona, Catalonia, Spain, shows high efficiency in HIV detection and linkage to care.

    Science.gov (United States)

    Meulbroek, M; Ditzel, E; Saz, J; Taboada, H; Pérez, F; Pérez, A; Carrillo, A; Font, G; Marazzi, G; Uya, J; Cabrero, J; Ingrami, M; Marín, R; Coll, J; Pujol, F

    2013-10-01

    We assessed the efficiency of BCN Checkpoint in detecting new cases of HIV infection and efficiently linking newly diagnosed individuals to care. This study analysed during 2007-2012 the number of tests performed and the number of persons tested in BCN Checkpoint, the HIV prevalence, global and in first visits, the capacity of HIV detection compared to the reported cases in MSM in Catalonia, and the linkage to care rate. During the six years a total of 17.319 tests were performed and 618 HIV-positive cases were detected. Median prevalence of clients who visited the centre for the first time was 5.4% (4.1-5.8). BCN Checkpoint detected 36.3% (35.0-40.4) of all reported cases in MSM during 2009-2011. Linkage to care was achieved directly in 90.5% of the cases and only 2.4% of cases were lost to follow-up. A community-based centre, addressed to a key population at risk, can be less effort consuming (time and funding) and show high efficiency in HIV detection and linkage to care. © 2013 British HIV Association.

  8. Enhancement of light extraction efficiency in OLED with two-dimensional photonic crystal slabs

    Science.gov (United States)

    Yan, Rongjin; Wang, Qingkang

    2006-06-01

    Light extraction efficiency of organic light emitting diode (OLED) based on various photonic crystal slab (PCS) structures was studied. By using the finite-difference time-domain (FDTD) method, we investigated the effect of several parameters, including filling factor and lattice constant, on the enhancement of light extraction efficiency of three basic PCSs, and got the most effective one. Two novel designs of "interlaced" and "double-interlaced" PCS structures based on the most effective basic PCS structure were introduced, and the "interlaced" one was proved to be even more efficient than its prototype. Large enhancement of light extraction efficiency resulted from the coupling to leaky modes in the expended light cone of a band structure, the diffraction in the space between columns, as well as the strong scattering at indium-tin-oxide/glass interfaces.

  9. Efficiency Enhancement of Gallium Arsenide Photovoltaics Using Solution-Processed Zinc Oxide Nanoparticle Light Scattering Layers

    Directory of Open Access Journals (Sweden)

    Yangsen Kang

    2015-01-01

    Full Text Available We demonstrate a high-throughput, solution-based process for subwavelength surface texturing of a III-V compound solar cell. A zinc oxide (ZnO nanoparticle ink is spray-coated directly on top of a gallium arsenide (GaAs solar cell. The nanostructured ZnO films have demonstrated antireflection and light scattering properties over the visible/near-infrared (NIR spectrum. The results show a broadband spectral enhancement of the solar cell external quantum efficiency (EQE, a 16% enhancement of short circuit current, and a 10% increase in photovoltaic efficiency.

  10. ENHANCING THE EFFICIENCY OF AZO-BASED DYE SENSITIZED SOLAR CELLS BY SURFACE TREATMENTS

    OpenAIRE

    JEANINA LUNGU; ADRIAN GEORGESCU; ANCA DUMBRAVA

    2015-01-01

    We studied the conductive glass and/or the semiconductor surface treatments with aluminum ions as a technique to enhance the characteristics of dye sensitized solar cells (DSSCs) based on Al-doped ZnO. The aluminum ions were deposited on the surfaces using aluminum isopropoxide as precursor, by an easy and efficient method. We measured the characteristics of the dye sensitized solar cells based on pre- and/or post-treated electrodes. Our study showed a clear enhancement of cells efficiencies ...

  11. A mechanistic understanding of processing additive-induced efficiency enhancement in bulk heterojunction organic solar cells

    KAUST Repository

    Schmidt, Kristin

    2013-10-31

    The addition of processing additives is a widely used approach to increase power conversion efficiencies for many organic solar cells. We present how additives change the polymer conformation in the casting solution leading to a more intermixed phase-segregated network structure of the active layer which in turn results in a 5-fold enhancement in efficiency. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Improved Efficiency of Miscible CO2 Floods and Enhanced Prospects for CO2 Flooding Heterogeneous Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, Reid B.; Schechter, David S.

    1999-10-15

    The goal of this project is to improve the efficiency of miscible CO2 floods and enhance the prospects for flooding heterogeneous reservoirs. This report provides results of the second year of the three-year project that will be exploring three principles: (1) Fluid and matrix interactions (understanding the problems). (2) Conformance control/sweep efficiency (solving the problems. 3) Reservoir simulation for improved oil recovery (predicting results).

  13. Enhancing the Emotional Wellbeing of Perinatally HIV Infected Youth across Global Contexts

    OpenAIRE

    Small, Latoya; Mercado, Micaela; Gopalan, Priya; Pardo, Gisselle; Ann Mellins, Claude; McKay, Mary McKernan

    2014-01-01

    Increased access to antiretroviral treatment worldwide makes it more possible for children diagnosed with HIV before their 15th birthday to age into adolescence and beyond. Many HIV+ youth navigate stressors including poverty and resource scarcity, which may converge to produce emotional distress. For over a decade, CHAMP (Collaborative HIV Prevention and Adolescent Mental Health Project) investigators partnered with youth, caregivers, providers and community stakeholders to address the healt...

  14. Policies to enhance prescribing efficiency in Europe: findings and future implications

    Directory of Open Access Journals (Sweden)

    Brian eGodman

    2011-01-01

    Full Text Available Introduction: European countries need to learn from each other to address unsustainable increases in pharmaceutical expenditures. Objective: To assess the influence of the many supply and demand side initiatives introduced across Europe to enhance prescribing efficiency in ambulatory care. As a result provide future guidance to countries. Methods: Cross national retrospective observational study of utilisation (DDDs - Defined Daily Doses and expenditure (Euros and local currency of Proton Pump Inhibitors (PPIs and statins among 19 European countries and regions principally from 2001 to 2007. Demand side measures categorised under the ‘4Es’ – education engineering, economics and enforcement. Results: Instigating supply side initiatives to lower the price of generics combined with demand side measures to enhance their prescribing is important to maximise prescribing efficiency. Just addressing one component will limit potential efficiency gains. The influence of demand side reforms appears additive, with multiple initiatives typically having a greater influence on increasing prescribing efficiency than single measures apart from potentially ‘enforcement’. There are also appreciable differences in expenditure (€/1000 inhabitants/ year between countries. Countries that have not introduced multiple measures to counteract commercial pressures to enhance the prescribing of generics have seen expenditures up to ten fold or more greater than countries that have instigated multiple demand side measures, although in selected populations. Conclusions: There are considerable opportunities for European countries to enhance their prescribing efficiency, with countries already learning from each other. The 4E methodology allows European countries to concisely capture the range of current demand side measures and plan for the future knowing that initiatives can be additive to further enhance their prescribing efficiency.

  15. TLR2-Modulating Lipoproteins of the Mycobacterium tuberculosis Complex Enhance the HIV Infectivity of CD4+ T Cells.

    Directory of Open Access Journals (Sweden)

    Ciaran Skerry

    Full Text Available Co-infection with Mycobacterium tuberculosis accelerates progression from HIV to AIDS. Our previous studies showed that M. tuberculosis complex, unlike M. smegmatis, enhances TLR2-dependent susceptibility of CD4+ T cells to HIV. The M. tuberculosis complex produces multiple TLR2-stimulating lipoproteins, which are absent in M. smegmatis. M. tuberculosis production of mature lipoproteins and TLR2 stimulation is dependent on cleavage by lipoprotein signal peptidase A (LspA. In order to determine the role of potential TLR2-stimulating lipoproteins on mycobacterial-mediated HIV infectivity of CD4+ T cells, we generated M. smegmatis recombinant strains overexpressing genes encoding various M. bovis BCG lipoproteins, as well as a Mycobacterium bovis BCG strain deficient in LspA (ΔlspA. Exposure of human peripheral blood mononuclear cells (PBMC to M. smegmatis strains overexpressing the BCG lipoproteins, LprF (p<0.01, LprH (p<0.05, LprI (p<0.05, LprP (p<0.001, LprQ (p<0.005, MPT83 (p<0.005, or PhoS1 (p<0.05, resulted in increased HIV infectivity of CD4+ T cells isolated from these PBMC. Conversely, infection of PBMC with ΔlspA reduced HIV infectivity of CD4+ T cells by 40% relative to BCG-infected cells (p<0.05. These results may have important implications for TB vaccination programs in areas with high mother-to-child HIV transmission.

  16. Enhanced efficiency in single-host white organic light-emitting diode by triplet exciton conversion

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qingyang, E-mail: wqy1527@163.com [State Key laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Zhang, Shiming [State Key laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Département of Chemical Engineering, École Polytechnique de Montréal, Montréal, Québec, Canada H3C3J7 (Canada); Yue, Shouzhen; Zhang, Zhensong [State Key laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Xie, Guohua [Institut für Angewandte Photophysik, Technische Universtität Dresden, Dresden 01062 (Germany); Zhao, Yi; Liu, Shiyong [State Key laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

    2013-11-15

    The authors observe that the external quantum efficiency (EQE) of the Iridium (III) bis(4-phenylthieno [3,2-c]pyridinato-N,C{sup 2′})acetylacetonate (PO-01) based yellow organic light-emitting diode (OLED) is significantly increased by uniformly co-doping Iridium (III)bis[(4,6-difluorophenyl)-pyridinato-N,C{sup 2−}] (FIrpic) and PO-01 into the same wide band-gap host of N,N{sup ′}-dicarbazolyl-3, 5-benzene (mCP). Detailed investigation indicates that the efficiency enhancement is ascribed to effective triplet exciton gathering by FIrpic, followed by energy transfer to PO-01. Compared to the control device, which has maximum EQE of 10.5%, an improved maximum EQE of 13.2% is obtained in the optimization white device based on FIrpic and PO-01 emission according to this principle. This work makes it easier for a single host white OLED to simultaneously harvest high efficiency in both blue and yellow units. Comprehensive experimental results show that this phenomenon can also be found and utilized in other popular hosts to realize more efficient white devices. -- Highlights: • This work makes easier for a single host white OLED to harvest high efficiency in both blue and yellow units. • Efficiency enhancement is ascribed to effective triplet exciton gathering by FIrpic, followed by energy transfer to PO-01. • This phenomenon can also be found and utilized in other popular hosts to realize more efficient white devices.

  17. Fullerene bisadducts for enhanced open-circuit voltages and efficiencies in polymer solar cells

    NARCIS (Netherlands)

    Lenes, Martijn; Wetzelaer, Gert-Jan A.H.; Kooistra, Floris B.; Veenstra, Sjoerd; Hummelen, Jan C.; Blom, Paul W.M.

    2008-01-01

    A fullerene bisadduct can enhance the efficiency of polymer:fullerene bulk heterojunction solar cells. The bisadduct has a LUMO that is 100 meV higher compared to that of [6,6]-phenyl C-61 butyric acid methyl ester (PCBM). This increases the open-circuit voltage of polymer: fullerene bulk

  18. Enhancement of Radiative Efficiency with Staggered InGaN Quantum Well Light Emitting Diodes

    Energy Technology Data Exchange (ETDEWEB)

    Tansu, Nelson; Dierolf, Volkmar; Huang, Gensheng; Penn, Samson; Zhao, Hongping; Liu, Guangyu; Li, Xiaohang; Poplawsky, Jonathan

    2011-07-14

    The technology on the large overlap InGaN QWs developed in this program is currently implemented in commercial technology in enhancing the internal quantum efficiency in major LED industry in US and Asia. The scientific finding from this work supported by the DOE enabled the implementation of this step-like staggered quantum well in the commercial LEDs.

  19. Enhancing Decoding Efficiency in Poor Readers via a Word Identification Game

    Science.gov (United States)

    Gorp, Karly; Segers, Eliane; Verhoeven, Ludo

    2017-01-01

    The effects of a word identification game aimed at enhancing decoding efficiency in poor readers were tested. Following a pretest-posttest-retention design with a waiting control group, 62 poor-reading Dutch second graders received a five-hour tablet intervention across a period of five weeks. During the intervention, participants practiced…

  20. Enhancing decoding efficiency in poor readers via a word identification game

    NARCIS (Netherlands)

    Gorp, K. van; Segers, P.C.J.; Verhoeven, L.T.W.

    2017-01-01

    The effects of a word identification game aimed at enhancing decoding efficiency in poor readers were tested. Following a pretest-posttest-retention design with a waiting control group, 62 poor-reading Dutch second graders received a five-hour tablet intervention across a period of five weeks.

  1. Efficient HIV-1 inhibition by a 16 nt-long RNA aptamer designed by combining in vitro selection and in silico optimisation strategies

    Science.gov (United States)

    Sánchez-Luque, Francisco J.; Stich, Michael; Manrubia, Susanna; Briones, Carlos; Berzal-Herranz, Alfredo

    2014-09-01

    The human immunodeficiency virus type-1 (HIV-1) genome contains multiple, highly conserved structural RNA domains that play key roles in essential viral processes. Interference with the function of these RNA domains either by disrupting their structures or by blocking their interaction with viral or cellular factors may seriously compromise HIV-1 viability. RNA aptamers are amongst the most promising synthetic molecules able to interact with structural domains of viral genomes. However, aptamer shortening up to their minimal active domain is usually necessary for scaling up production, what requires very time-consuming, trial-and-error approaches. Here we report on the in vitro selection of 64 nt-long specific aptamers against the complete 5'-untranslated region of HIV-1 genome, which inhibit more than 75% of HIV-1 production in a human cell line. The analysis of the selected sequences and structures allowed for the identification of a highly conserved 16 nt-long stem-loop motif containing a common 8 nt-long apical loop. Based on this result, an in silico designed 16 nt-long RNA aptamer, termed RNApt16, was synthesized, with sequence 5'-CCCCGGCAAGGAGGGG-3'. The HIV-1 inhibition efficiency of such an aptamer was close to 85%, thus constituting the shortest RNA molecule so far described that efficiently interferes with HIV-1 replication.

  2. Enhanced Conversion Efficiency of III–V Triple-junction Solar Cells with Graphene Quantum Dots

    Science.gov (United States)

    Lin, Tzu-Neng; Santiago, Svette Reina Merden S.; Zheng, Jie-An; Chao, Yu-Chiang; Yuan, Chi-Tsu; Shen, Ji-Lin; Wu, Chih-Hung; Lin, Cheng- An J.; Liu, Wei-Ren; Cheng, Ming-Chiang; Chou, Wu-Ching

    2016-01-01

    Graphene has been used to synthesize graphene quantum dots (GQDs) via pulsed laser ablation. By depositing the synthesized GQDs on the surface of InGaP/InGaAs/Ge triple-junction solar cells, the short-circuit current, fill factor, and conversion efficiency were enhanced remarkably. As the GQD concentration is increased, the conversion efficiency in the solar cell increases accordingly. A conversion efficiency of 33.2% for InGaP/InGaAs/Ge triple-junction solar cells has been achieved at the GQD concentration of 1.2 mg/ml, corresponding to a 35% enhancement compared to the cell without GQDs. On the basis of time-resolved photoluminescence, external quantum efficiency, and work-function measurements, we suggest that the efficiency enhancement in the InGaP/InGaAs/Ge triple-junction solar cells is primarily caused by the carrier injection from GQDs to the InGaP top subcell. PMID:27982073

  3. Enhanced Conversion Efficiency of III-V Triple-junction Solar Cells with Graphene Quantum Dots

    Science.gov (United States)

    Lin, Tzu-Neng; Santiago, Svette Reina Merden S.; Zheng, Jie-An; Chao, Yu-Chiang; Yuan, Chi-Tsu; Shen, Ji-Lin; Wu, Chih-Hung; Lin, Cheng-An J.; Liu, Wei-Ren; Cheng, Ming-Chiang; Chou, Wu-Ching

    2016-12-01

    Graphene has been used to synthesize graphene quantum dots (GQDs) via pulsed laser ablation. By depositing the synthesized GQDs on the surface of InGaP/InGaAs/Ge triple-junction solar cells, the short-circuit current, fill factor, and conversion efficiency were enhanced remarkably. As the GQD concentration is increased, the conversion efficiency in the solar cell increases accordingly. A conversion efficiency of 33.2% for InGaP/InGaAs/Ge triple-junction solar cells has been achieved at the GQD concentration of 1.2 mg/ml, corresponding to a 35% enhancement compared to the cell without GQDs. On the basis of time-resolved photoluminescence, external quantum efficiency, and work-function measurements, we suggest that the efficiency enhancement in the InGaP/InGaAs/Ge triple-junction solar cells is primarily caused by the carrier injection from GQDs to the InGaP top subcell.

  4. Gene transfer occurs with enhanced efficiency in biofilms and induces enhanced stabilisation of the biofilm structure

    DEFF Research Database (Denmark)

    Molin, Søren; Tolker-Nielsen, Tim

    2003-01-01

    There has been much interest in bioremediation based on the introduction of bacteria able to catabolise recalcitrant compounds deposited in the environment. In particular, the delivery of catabolic information in the form of conjugative plasmids to bacterial populations in situ has great potential....... As most bacteria in the environment live in surface-associated communities (biofilms), the gene transfer systems within these communities need to be better characterised for bio-enhancement strategies to be developed. Recent findings suggest that gene transfer does take place within biofilms, but studies...... also identified limitations and bottlenecks of the process. The dense population structure in biofilms increases plasmid dispersal by conjugation, and the conjugation mechanism itself may stimulate biofilm development. Moreover, DNA release and transformation seem to be part of a biofilm-related life...

  5. Novel mucosal DNA-MVA HIV vaccination in which DNA-IL-12 plus cholera toxin B subunit (CTB) cooperates to enhance cellular systemic and mucosal genital tract immunity.

    Science.gov (United States)

    Maeto, Cynthia; Rodríguez, Ana María; Holgado, María Pía; Falivene, Juliana; Gherardi, María Magdalena

    2014-01-01

    Induction of local antiviral immune responses at the mucosal portal surfaces where HIV-1 and other viral pathogens are usually first encountered remains a primary goal for most vaccines against mucosally acquired viral infections. Exploring mucosal immunization regimes in order to find optimal vector combinations and also appropriate mucosal adjuvants in the HIV vaccine development is decisive. In this study we analyzed the interaction of DNA-IL-12 and cholera toxin B subunit (CTB) after their mucosal administration in DNA prime/MVA boost intranasal regimes, defining the cooperation of both adjuvants to enhance immune responses against the HIV-1 Env antigen. Our results demonstrated that nasal mucosal DNA/MVA immunization schemes can be effectively improved by the co-delivery of DNA-IL-12 plus CTB inducing elevated HIV-specific CD8 responses in spleen and more importantly in genital tract and genito-rectal draining lymph nodes. Remarkably, these CTL responses were of superior quality showing higher avidity, polyfunctionality and a broader cytokine profile. After IL-12+CTB co-delivery, the cellular responses induced showed an enhanced breadth recognizing with higher efficiency Env peptides from different subtypes. Even more, an in vivo CTL cytolytic assay demonstrated the higher specific CD8 T-cell performance after the IL-12+CTB immunization showing in an indirect manner its potential protective capacity. Improvements observed were maintained during the memory phase where we found higher proportions of specific central memory and T memory stem-like cells T-cell subpopulations. Together, our data show that DNA-IL-12 plus CTB can be effectively employed acting as mucosal adjuvants during DNA prime/MVA boost intranasal vaccinations, enhancing magnitude and quality of HIV-specific systemic and mucosal immune responses.

  6. Enhanced Solar Photoelectrochemical Conversion Efficiency of ZnO:Cu Electrodes for Water-Splitting Application

    Directory of Open Access Journals (Sweden)

    Rekha Dom

    2013-01-01

    Full Text Available n-type ZnO:Cu photoanodes were fabricated by simple spray pyrolysis deposition technique. Influence of low concentration (range ~10−4–10−1% of Cu doping in hexagonal ZnO lattice on its photoelectrochemical performance has been investigated. The doped photoanodes displayed 7-time enhanced conversion efficiencies with respect to their undoped counterpart, as estimated from the photocurrents generated under simulated solar radiation. This is the highest enhancement in the solar conversion efficiency reported so far for the Cu-doped ZnO. This performance is attributed to the red shift in the band gap of the Cu-doped films and is in accordance with the incident-photon-current-conversion efficiency (IPCE measurements. Electrochemical studies reveal an n-type nature of these photoanodes. Thus, the study indicates a high potential of doped ZnO films for solar energy applications, in purview of the development of simple nanostructuring methodologies.

  7. Efficiency Enhancement of Silicon Heterojunction Solar Cells via Photon Management Using Graphene Quantum Dot as Downconverters

    KAUST Repository

    Tsai, Meng-Lin

    2015-12-16

    By employing graphene quantum dots (GQDs), we have achieved a high efficiency of 16.55% in n-type Si heterojunction solar cells. The efficiency enhancement is based on the photon downconversion phenomenon of GQDs to make more photons absorbed in the depletion region for effective carrier separation, leading to the enhanced photovoltaic effect. The short circuit current and the fill factor are increased from 35.31 to 37.47 mA/cm2 and 70.29% to 72.51%, respectively. The work demonstrated here holds the promise for incorporating graphene-based materials in commercially available solar devices for developing ultra-high efficiency photovoltaic cells in the future.

  8. 77 FR 36550 - Office of Clinical and Preventive Services Funding Opportunity: National HIV Program for Enhanced...

    Science.gov (United States)

    2012-06-19

    ... PLWHA. Awardee activities will seek to: increase access to HIV related services, reduce stigma, make HIV... reduce stigma. 3. Reaching a wide range of persons including diverse age and sex categories. If specific..., day care, health care, or early childhood development services are provided to children. This is...

  9. Operational Efficiency And Customer Satisfaction of Restaurants: Basis For Business Operation Enhancement

    Directory of Open Access Journals (Sweden)

    Annie Gay Barlan-Espino

    2017-02-01

    Full Text Available Restaurants’ primary objective is to provide comfort and satisfaction to guest without compromising the operational efficiency of the business. This research aimed to determine the operational efficiency and customer satisfaction of restaurants as a basis for business operation enhancement. Specifically to determine the operational efficiency of the restaurant in terms of kitchen operations and dining operations and the level of customer satisfaction of the restaurant business in terms of: Product, Policies, People, Processes and Proactivity as well as the problems encountered by the restaurant in their operation and customer service. Descriptive research design was used with managers and customers as respondents of the study. It was concluded that majority of the restaurants are operating for more than a year with sufficient number of employees having enough seating capacity that accommodate large volume of customers. Restaurants are efficient on the aspect of kitchen and dining operations and sometimes encountered problems. Customers are satisfied in terms of 5 P’s. It was found out that there is no significant difference in the operational efficiency of restaurant when grouped according to profile variables. An action plan for continuous business operation enhancement on operational efficiency and customer satisfaction was proposed.

  10. Internal quantum efficiency enhancement of GaInN/GaN quantum-well structures using Ag nanoparticles

    DEFF Research Database (Denmark)

    Iida, Daisuke; Fadil, Ahmed; Chen, Yuntian

    2015-01-01

    We report internal quantum efficiency enhancement of thin p-GaN green quantumwell structure using self-assembled Ag nanoparticles. Temperature dependent photoluminescence measurements are conducted to determine the internal quantum efficiency. The impact of excitation power density...

  11. Slow-light-enhanced energy efficiency for graphene microheaters on silicon photonic crystal waveguides.

    Science.gov (United States)

    Yan, Siqi; Zhu, Xiaolong; Frandsen, Lars Hagedorn; Xiao, Sanshui; Mortensen, N Asger; Dong, Jianji; Ding, Yunhong

    2017-02-09

    Slow light has been widely utilized to obtain enhanced nonlinearities, enhanced spontaneous emissions and increased phase shifts owing to its ability to promote light-matter interactions. By incorporating a graphene on a slow-light silicon photonic crystal waveguide, here we experimentally demonstrate an energy-efficient graphene microheater with a tuning efficiency of 1.07 nmmW-1 and power consumption per free spectral range of 3.99 mW. The rise and decay times (10-90%) are only 750 and 525 ns, which, to the best of our knowledge, are the fastest reported response times for microheaters in silicon photonics. The corresponding figure of merit of the device is 2.543 nW s, one order of magnitude better than results reported in previous studies. The influence of the length and shape of the graphene heater to the tuning efficiency is further investigated, providing valuable guidelines for enhancing the tuning efficiency of the graphene microheater.

  12. Enhanced bioleaching efficiency of metals from E-wastes driven by biochar

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shuhua; Zheng, Yue; Yan, Weifu; Chen, Lixiang [CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Dummi Mahadevan, Gurumurthy [CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 (China); Zhao, Feng, E-mail: fzhao@iue.ac.cn [CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 (China)

    2016-12-15

    Electronic wastes (E-wastes) contain a huge amount of valuable metals that are worth recovering. Bioleaching has attracted widespread attention as an environment-friendly and low-cost technology for the recycling of E-wastes. To avoid the disadvantages of being time-consuming or having a relatively low efficiency, biochar with redox activity was used to enhance bioleaching efficiency of metals from a basic E-waste (i.e., printed circuit boards in this study). The role of biochar was examined through three basic processes: Carbon-mediated, Sulfur-mediated and Iron-mediated bioleaching pathways. Although no obvious enhancement of bioleaching performance was observed in the C-mediated and S-mediated systems, Fe-mediated bioleaching was significantly promoted by the participation of biochar, and its leaching time was decreased by one-third compared with that of a biochar-free system. By mapping the dynamic concentration of Fe(II) and Cu(II), biochar was proved to facilitate the redox action between Fe(II) to Fe(III), which resulted in effective leaching of Cu. Two dominant functional species consisting of Alicyclobacillus spp. and Sulfobacillus spp. may cooperate in the Fe-mediated bioleaching system, and the ratio of these two species was regulated by biochar for enhancing the efficiency of bioleaching. Hence, this work provides a method to improve bioleaching efficiency with low-cost solid redox media.

  13. Enhancing global control of alcohol to reduce unsafe sex and HIV in sub-Saharan Africa

    Directory of Open Access Journals (Sweden)

    Rees Helen V

    2009-11-01

    Full Text Available Abstract Sub-Saharan Africa carries a massive dual burden of HIV and alcohol disease, and these pandemics are inextricably linked. Physiological and behavioural research indicates that alcohol independently affects decision-making concerning sex, and skills for negotiating condoms and their correct use. More than 20 studies in Africa have reported higher occurrence of HIV among people with problem drinking; a finding strongly consistent across studies and similar among women and men. Conflation of HIV and alcohol disease in these setting is not surprising given patterns of heavy-episodic drinking and that drinking contexts are often coterminous with opportunities for sexual encounters. HIV and alcohol also share common ground with sexual violence. Both perpetrators and victims of sexual violence have a high likelihood of having drunk alcohol prior to the incident, as with most forms of violence and injury in sub-Saharan Africa. Reducing alcohol harms necessitates multi-level interventions and should be considered a key component of structural interventions to alleviate the burden of HIV and sexual violence. Brief interventions for people with problem drinking (an important component of primary health care, must incorporate specific discussion of links between alcohol and unsafe sex, and consequences thereof. Interventions to reduce alcohol harm among HIV-infected persons are also an important element in positive-prevention initiatives. Most importantly, implementation of known effective interventions could alleviate a large portion of the alcohol-attributable burden of disease, including its effects on unsafe sex, unintended pregnancy and HIV transmission.

  14. A novel strategy for efficient production of anti-V3 human scFvs against HIV-1 clade C

    Directory of Open Access Journals (Sweden)

    Kumar Rajesh

    2012-11-01

    phage. After selection, the phage clones were propagated in a clonal manner. Conclusions This strategy can be efficiently used and is cost effective for the generation of diverse recombinant antibodies. This is the first study to generate anti-V3 scFvs against HIV-1 Clade C.

  15. Disordered photonics coupled with embedded nano-Au plasmonics inducing efficient photocurrent enhancement.

    Science.gov (United States)

    Li, Jing; Wang, Junling; Dai, Zhihui; Li, Hongbo

    2018-01-01

    Spatial order used to be considered as a benefit for photonics; but recently the study of disorder has broken into people's horizons for its strong random scattering of light. In this work, disordered photonics coupled with plasmonics for efficiently enhanced photocurrent was first investigated using Au-ZnO nanowire array as a model. The embedded Au-ZnO nanowire array was facilely prepared using a template-free electrodeposition method. On the optimal plasmonic substrate, the photocurrent of disorder-enhanced Au-ZnO nanowire array is about 20-fold that of ZnO nanowire array. Both the plasmonic effect of Au NPs such as localized surface plasmons, surface plasmon polarizations and the disorder-enhanced photonics in the hybrid structure are available to improve the photoelectric conversion efficiency by enhancing the trapping of the simulated sunlight and the collection of charge carriers. Herein, disordered photonics was coupled with plasmonics to explain for the enhanced photocurrent. This work also provided a facile fabricating avenue for plasmonic noble metal embedded in semiconductor devices. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Plasmonic organic photovoltaic devices with graphene based buffer layers for stability and efficiency enhancement

    Science.gov (United States)

    Stratakis, Emmanuel; Stylianakis, Minas M.; Koudoumas, Emmanuel; Kymakis, Emmanuel

    2013-05-01

    Enhancement of photoconversion efficiency (PCE) and stability in bulk heterojunction (BHJ) plasmonic organic photovoltaic devices (OPVs) incorporating graphene oxide (GO) thin films as the hole transport layer (HTL) and surfactant free Au nanoparticles (NPs) between the GO HTL and the photoactive layers is demonstrated. In particular the plasmonic GO-based devices exhibited a performance enhancement by 30% compared to the devices using the traditional PEDOT:PSS layer. Likewise, they preserved 50% of their initial PCE after 45 h of continuous illumination, contrary to the PEDOT:PSS-based ones that die after 20 h. The performance increase is attributed to the improved photocurrent and fill factor owing to the enhanced exciton generation rate due to NP-induced plasmon absorption enhancement. Besides this, the stability enhancement can be attributed to limited oxygen and/or indium diffusion from the indium tin oxide (ITO) electrode into the active layer. The industrial exploitation of composite GO/NPs as efficient buffer layers in OPVs is envisaged.

  17. Enhanced efficiency of solar-driven thermoelectric generator with femtosecond laser-textured metals.

    Science.gov (United States)

    Hwang, Taek Yong; Vorobyev, A Y; Guo, Chunlei

    2011-07-04

    Through femtosecond laser irradiation, we produce in this work a unique type of surface nanostructure on Al that have enhanced absorption at UV and visible but a relatively small emissivity in infrared. By integrating this laser-treated Al to a solar-driven thermoelectric generator, we show that the thermoelectric generator integrated with the femtosecond laser-treated Al foil generates a significantly higher power than the ones without. Our study shows that our technique can dramatically enhance the efficiency of solar-driven thermoelectric devices that may lead to a leap forward in solar energy harnessing.

  18. Enhancement of thermoelectric efficiency by quantum interference effects in trilayer silicene flakes.

    Science.gov (United States)

    Cortés, Natalia; Rosales, L; Chico, Leonor; Pacheco, M; Orellana, P A

    2017-01-11

    In recent years, the enhancement of thermoelectric efficiencies has been accomplished in nanoscale systems by making use of quantum effects. We exploit the presence of quantum interference phenomena such as bound states in the continuum and Fano antiresonances in trilayer silicene flakes to produce sharp changes in the electronic transmission of the system. By applying symmetric gate voltages the thermoelectric properties can be tuned and, for particular flake lengths, a great enhancement of the figure of merit can be achieved. We show that the most favorable configurations are those in which the electronic transmission is dominated by the coupling of bound states to the continuum, tuned by an external gate.

  19. Efficient Surface Enhanced Raman Scattering substrates from femtosecond laser based fabrication

    Science.gov (United States)

    Parmar, Vinod; Kanaujia, Pawan K.; Bommali, Ravi Kumar; Vijaya Prakash, G.

    2017-10-01

    A fast and simple femtosecond laser based methodology for efficient Surface Enhanced Raman Scattering (SERS) substrate fabrication has been proposed. Both nano scaffold silicon (black silicon) and gold nanoparticles (Au-NP) are fabricated by femtosecond laser based technique for mass production. Nano rough silicon scaffold enables large electromagnetic fields for the localized surface plasmons from decorated metallic nanoparticles. Thus giant enhancement (approximately in the order of 104) of Raman signal arises from the mixed effects of electron-photon-phonon coupling, even at nanomolar concentrations of test organic species (Rhodamine 6G). Proposed process demonstrates the low-cost and label-less application ability from these large-area SERS substrates.

  20. Linearization and efficiency enhancement techniques for silicon power amplifiers from RF to mmW

    CERN Document Server

    Kerhervé, Eric

    2015-01-01

    This book provides an overview of current efficiency enhancement and linearization techniques for silicon power amplifier designs. It examines the latest state of the art technologies and design techniques to address challenges for RF cellular mobile, base stations, and RF and mmW WLAN applications. Coverage includes material on current silicon (CMOS, SiGe) RF and mmW power amplifier designs, focusing on advantages and disadvantages compared with traditional GaAs implementations. With this book you will learn: The principles of linearization and efficiency improvement techniquesThe arch

  1. Heat management methodology for enhanced global efficiency in hybrid electric vehicles

    Directory of Open Access Journals (Sweden)

    F. Claude

    2017-09-01

    Full Text Available The transportation impact on pollution and global climate change, has forced the automotive sector to search for more ecological solutions. Owing to the different properties of Fuel Cell (FC, real potential for reducing vehicles’ emissions has been witnessed. The optimization of FC integration within Electric Vehicles (EVs is one of the original solutions. This paper presents an innovating solution of multi-stack Fuel Cell Electrical Vehicle (FCEV in terms of efficiency, durability and ecological impact on environment. The main objective is to illustrate the interest of using the multi-stack FC system on the global autonomy, cycling, and efficiency enhancement, besides optimizing its operation performance.

  2. Exploring vortex enhancement and manipulation mechanisms in jellyfish that contributes to energetically efficient propulsion.

    Science.gov (United States)

    Gemmell, Brad J; Costello, John H; Colin, Sean P

    2014-01-01

    The ability of animals to propel themselves efficiently through a fluid medium is ecologically advantageous. Flexible components that influence vortex interactions are widespread among animal propulsors. However the mechanisms by which vortices are enhanced and appropriately positioned for thrust generation are still poorly understood. Here, we describe how kinematic propulsor movements of a jellyfish can enhance and reposition a vortex ring that allows the recapture of wake energy for secondary thrust generation and efficient locomotion. We use high-speed video and digital particle image velocimetry (DPIV) to resolve kinematics simultaneously with fluid structures. These results provide new insight into how animals can manipulate fluid structures to reduce metabolic energy demands of swimming muscles and may have implications in bio-inspired design.

  3. Efficient Hardware Implementation For Fingerprint Image Enhancement Using Anisotropic Gaussian Filter.

    Science.gov (United States)

    Khan, Tariq Mahmood; Bailey, Donald G; Khan, Mohammad A U; Kong, Yinan

    2017-05-01

    A real-time image filtering technique is proposed which could result in faster implementation for fingerprint image enhancement. One major hurdle associated with fingerprint filtering techniques is the expensive nature of their hardware implementations. To circumvent this, a modified anisotropic Gaussian filter is efficiently adopted in hardware by decomposing the filter into two orthogonal Gaussians and an oriented line Gaussian. An architecture is developed for dynamically controlling the orientation of the line Gaussian filter. To further improve the performance of the filter, the input image is homogenized by a local image normalization. In the proposed structure, for a middle-range reconfigurable FPGA, both parallel compute-intensive and real-time demands were achieved. We manage to efficiently speed up the image-processing time and improve the resource utilization of the FPGA. Test results show an improved speed for its hardware architecture while maintaining reasonable enhancement benchmarks.

  4. Molecular Lock: A Versatile Key to Enhance Efficiency and Stability of Organic Solar Cells.

    Science.gov (United States)

    Cheng, Pei; Yan, Cenqi; Lau, Tsz-Ki; Mai, Jiangquan; Lu, Xinhui; Zhan, Xiaowei

    2016-07-01

    4,4'-Biphenol (BPO), a common, cheap chemical, is employed as a "molecular lock" in blends of fluorine-containing polymer or small molecule donors and fullerene acceptors to lock donors via hydrogen bond formed between the donor and BPO. The molecular lock is a versatile key to enhance the efficiency and stability of organic solar cells simultaneously. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Hydrodynamic cavitation as a strategy to enhance the efficiency of lignocellulosic biomass pretreatment

    DEFF Research Database (Denmark)

    Terán Hilares, Ruly; Ramos, Lucas; da Silva, Silvio Silvério

    2017-01-01

    Hydrodynamic cavitation (HC) is a process technology with potential for application in different areas including environmental, food processing, and biofuels production. Although HC is an undesirable phenomenon for hydraulic equipment, the net energy released during this process is enough...... to accelerate certain chemical reactions. The application of cavitation energy to enhance the efficiency of lignocellulosic biomass pretreatment is an interesting strategy proposed for integration in biorefineries for the production of bio-based products. Moreover, the use of an HC-assisted process...

  6. Kazakhstan can achieve ambitious HIV targets despite expected donor withdrawal by combining improved ART procurement mechanisms with allocative and implementation efficiencies.

    Directory of Open Access Journals (Sweden)

    Andrew J Shattock

    Full Text Available Despite a non-decreasing HIV epidemic, international donors are soon expected to withdraw funding from Kazakhstan. Here we analyze how allocative, implementation, and technical efficiencies could strengthen the national HIV response under assumptions of future budget levels.We used the Optima model to project future scenarios of the HIV epidemic in Kazakhstan that varied in future antiretroviral treatment unit costs and management expenditure-two areas identified for potential cost-reductions. We determined optimal allocations across HIV programs to satisfy either national targets or ambitious targets. For each scenario, we considered two cases of future HIV financing: the 2014 national budget maintained into the future and the 2014 budget without current international investment.Kazakhstan can achieve its national HIV targets with the current budget by (1 optimally re-allocating resources across programs and (2 either securing a 35% [30%-39%] reduction in antiretroviral treatment drug costs or reducing management costs by 44% [36%-58%] of 2014 levels. Alternatively, a combination of antiretroviral treatment and management cost-reductions could be sufficient. Furthermore, Kazakhstan can achieve ambitious targets of halving new infections and AIDS-related deaths by 2020 compared to 2014 levels by attaining a 67% reduction in antiretroviral treatment costs, a 19% [14%-27%] reduction in management costs, and allocating resources optimally.With Kazakhstan facing impending donor withdrawal, it is important for the HIV response to achieve more with available resources. This analysis can help to guide HIV response planners in directing available funding to achieve the greatest yield from investments. The key changes recommended were considered realistic by Kazakhstan country representatives.

  7. Nanoparticle-enhanced synergistic HIFU ablation and transarterial chemoembolization for efficient cancer therapy

    Science.gov (United States)

    You, Yufeng; Wang, Zhigang; Ran, Haitao; Zheng, Yuanyi; Wang, Dong; Xu, Jinshun; Wang, Zhibiao; Chen, Yu; Li, Pan

    2016-02-01

    High-intensity focused ultrasound (HIFU) is being generally explored as a non-invasive therapeutic modality to treat solid tumors. However, the clinical use of HIFU for large and deep tumor-ablation applications such as hepatocellular carcinoma (HCC) is currently entangled with long treatment duration and high operating energy. This critical issue can be potentially resolved by the introduction of HIFU synergistic agents (SAs). Traditional SAs such as microbubbles and microparticles face the problem of large size, short cycle time, damage to mononuclear phagocytic system and unsatisfactory targeting efficiency. In this work, we have developed a facile and versatile nanoparticle-based HIFU synergistic cancer surgery enhanced by transarterial chemoembolization for high-efficiency HCC treatment based on elaborately designed Fe3O4-PFH/PLGA nanocapsules. Multifunctional Fe3O4-PFH/PLGA nanocapsules were administrated into tumor tissues via transarterial injection combined with Lipiodol to achieve high tumor accumulation because transarterial chemoembolization by Lipiodol could block the blood vessels. The high synergistic HIFU ablation effect was successfully achieved against HCC tumors based on the phase-transformation performance of the perfluorohexane (PFH) inner core in the composite nanocapsules, as systematically demonstrated in VX2 liver tumor xenograft in rabbits. Multifunctional Fe3O4-PFH/PLGA nanocapsules were also demonstrated as efficient contrast agents for ultrasound, magnetic resonance and photoacoustic tri-modality imagings, potentially applicable for imaging-guided HIFU synergistic surgery. Therefore, the elaborate integration of traditional transarterial chemoembolization with recently developed nanoparticle-enhanced HIFU cancer surgery could efficiently enhance the HCC cancer treatment outcome, initiating a new and efficient therapeutic protocol/modality for clinic cancer treatment.

  8. A new hardware-efficient algorithm and reconfigurable architecture for image contrast enhancement.

    Science.gov (United States)

    Huang, Shih-Chia; Chen, Wen-Chieh

    2014-10-01

    Contrast enhancement is crucial when generating high quality images for image processing applications, such as digital image or video photography, liquid crystal display processing, and medical image analysis. In order to achieve real-time performance for high-definition video applications, it is necessary to design efficient contrast enhancement hardware architecture to meet the needs of real-time processing. In this paper, we propose a novel hardware-oriented contrast enhancement algorithm which can be implemented effectively for hardware design. In order to be considered for hardware implementation, approximation techniques are proposed to reduce these complex computations during performance of the contrast enhancement algorithm. The proposed hardware-oriented contrast enhancement algorithm achieves good image quality by measuring the results of qualitative and quantitative analyzes. To decrease hardware cost and improve hardware utilization for real-time performance, a reduction in circuit area is proposed through use of parameter-controlled reconfigurable architecture. The experiment results show that the proposed hardware-oriented contrast enhancement algorithm can provide an average frame rate of 48.23 frames/s at high definition resolution 1920 × 1080.

  9. Efficiency enhancement of octave-bandwidth traveling wave tubes by use of multistage depressed collectors

    Science.gov (United States)

    Ramins, P.; Fox, T. A.

    1979-01-01

    Small, three- and five-stage depressed collectors were evaluated in conjunction with a 4.8- to 9.6-GHz TWT of 325- to 675-W power output and a beam of 0.5 microperv. The multistage depressed collector (MDC) performed well even though its design had been optimized for a TWT of identical design but considerably less output power. Despite large, fixed losses significant efficiency enhancement was demonstrated with both the three- and five-stage depressed collectors. At saturated rf power output, the improvement in the overall efficiency ranged from a factor of 2.5 to 3.0 for the three-stage collector and a factor of 3.0 to 3.5 for the five-stage collector. At saturation three-stage collector efficiencies of 77 to 80 percent and five-stage collector efficiencies of 81 to 84 percent were obtained across the frequency band. An overall efficiency of 37.0 to 44.3 percent across the frequency band of 4.8 to 9.6 GHz was demonstrated with the use of harmonic injection. For operation below saturation, even larger relative improvements in the overall TWT efficiency were demonstrated. Collector performance was relatively insensitive to the degree of regulation of the collector power supply.

  10. Flexible Grouping for Enhanced Energy Utilization Efficiency in Battery Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Weiping Diao

    2016-06-01

    Full Text Available As a critical subsystem in electric vehicles and smart grids, a battery energy storage system plays an essential role in enhancement of reliable operation and system performance. In such applications, a battery energy storage system is required to provide high energy utilization efficiency, as well as reliability. However, capacity inconsistency of batteries affects energy utilization efficiency dramatically; and the situation becomes more severe after hundreds of cycles because battery capacities change randomly due to non-uniform aging. Capacity mismatch can be solved by decomposing a cluster of batteries in series into several low voltage battery packs. This paper introduces a new analysis method to optimize energy utilization efficiency by finding the best number of batteries in a pack, based on capacity distribution, order statistics, central limit theorem, and converter efficiency. Considering both battery energy utilization and power electronics efficiency, it establishes that there is a maximum energy utilization efficiency under a given capacity distribution among a certain number of batteries, which provides a basic analysis for system-level optimization of a battery system throughout its life cycle. Quantitative analysis results based on aging data are illustrated, and a prototype of flexible energy storage systems is built to verify this analysis.

  11. Motivational Interviewing among HIV Health Care Providers: Challenges and opportunities to enhance engagement and retention in care in Buenos Aires, Argentina

    Science.gov (United States)

    Bofill, Lina; Weiss, Stephen M; Lucas, Mar; Bordato, Alejandra; Dorigo, Analia; Fernandez-Cabanillas, Graciela; Aristegui, Ines; Lopez, Maria; Waldrop-Valverde, Drenna; Jones, Deborah

    2016-01-01

    Providers’ response to Motivational Interviewing (MI) to improve engagement and retention in care among challenging patients with HIV in Argentina were evaluated. 12 HIV care physicians participated and video recordings pre- and post-MI training were obtained. One week post-training 11/12 participants were committed to using MI strategies during consult session. 9/12 participants demonstrated appropriate utilization of MI techniques and increased adherence focused discussion and care (t = 3.59, p = .006). MI appears to be a viable strategy to enhance engagement and retention in challenging HIV patients. PMID:26056148

  12. Quantum efficiency enhancement in nanocrystals using nonradiative energy transfer with optimized donor-acceptor ratio for hybrid LEDs

    Science.gov (United States)

    Nizamoglu, Sedat; Akin, Onur; Demir, Hilmi Volkan

    2009-06-01

    The quantum efficiency enhancement in nanocrystal solids is critically important for their efficient use as luminophors on color-conversion light emitting diodes (LEDs). For this purpose, we investigate energy gradient mixture of nanocrystal solids for recycling their trapped excitons by varying their donor-acceptor nanocrystal ratios and study the resulting quantum efficiency enhancement as a function of the donor-acceptor ratio in the solid film for hybrid LEDs. We achieve a maximum quantum efficiency enhancement of 17% in these nanocrystal solids when the donor-acceptor ratio is 1:1, demonstrating their highly modified time-resolved photoluminescence decays to reveal the kinetics of strong energy transfer between them.

  13. Enhancing Public Health HIV Interventions: A Qualitative Meta-Synthesis and Systematic Review of Studies to Improve Linkage to Care, Adherence, and Retention

    Directory of Open Access Journals (Sweden)

    Joseph D. Tucker

    2017-03-01

    Full Text Available Although HIV services are expanding, few have reached the scale necessary to support universal viral suppression of individuals living with HIV. The purpose of this systematic review was to summarize the qualitative evidence evaluating public health HIV interventions to enhance linkage to care, antiretroviral drug (ARV adherence, and retention in care. We searched 19 databases without language restrictions. The review collated data from three separate qualitative evidence reviews addressing each of the three outcomes along the care continuum. 21,738 citations were identified and 24 studies were included in the evidence review. Among low and middle-income countries in Africa, men living with HIV had decreased engagement in interventions compared to women and this lack of engagement among men also influenced the willingness of their partners to engage in services. Four structural issues (poverty, unstable housing, food insecurity, lack of transportation mediated the feasibility and acceptability of public health HIV interventions. Individuals living with HIV identified unmet mental health needs that interfered with their ability to access HIV services. Persistent social and cultural factors contribute to disparities in HIV outcomes across the continuum of care, shaping the context of service delivery among important subpopulations.

  14. Enhancing Public Health HIV Interventions: A Qualitative Meta-Synthesis and Systematic Review of Studies to Improve Linkage to Care, Adherence, and Retention.

    Science.gov (United States)

    Tucker, Joseph D; Tso, Lai Sze; Hall, Brian; Ma, Qingyan; Beanland, Rachel; Best, John; Li, Haochu; Lackey, Mellanye; Marley, Gifty; Rich, Zachary C; Sou, Ka-Lon; Doherty, Meg

    2017-03-01

    Although HIV services are expanding, few have reached the scale necessary to support universal viral suppression of individuals living with HIV. The purpose of this systematic review was to summarize the qualitative evidence evaluating public health HIV interventions to enhance linkage to care, antiretroviral drug (ARV) adherence, and retention in care. We searched 19 databases without language restrictions. The review collated data from three separate qualitative evidence reviews addressing each of the three outcomes along the care continuum. 21,738 citations were identified and 24 studies were included in the evidence review. Among low and middle-income countries in Africa, men living with HIV had decreased engagement in interventions compared to women and this lack of engagement among men also influenced the willingness of their partners to engage in services. Four structural issues (poverty, unstable housing, food insecurity, lack of transportation) mediated the feasibility and acceptability of public health HIV interventions. Individuals living with HIV identified unmet mental health needs that interfered with their ability to access HIV services. Persistent social and cultural factors contribute to disparities in HIV outcomes across the continuum of care, shaping the context of service delivery among important subpopulations. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Plasmon-Assisted Efficiency Enhancement of Eu3+-Doped Tellurite Glass-Covered Solar Cells

    Science.gov (United States)

    Lima, Bismarck C.; Gómez-Malagón, L. A.; Gomes, A. S. L.; Garcia, J. A. M.; Kassab, L. R. P.

    2017-12-01

    Rare-earth-doped tellurite glass containing metallic nanoparticles can be exploited to manage the solar spectrum in order to increase solar cell efficiency. It is therefore possible to modify the incident solar spectrum profile to the spectrum that optimizes the solar cell recombination process by covering the solar cell with plasmonic luminescent downshifting layers. With this approach, the losses due to thermalization are minimized and the efficiency is increased. Due to the down-conversion process that couples the plasmon resonance of the metallic nanoparticles and the rare-earth electronic energy levels, it is possible to convert photons from the ultraviolet region to the visible and near-band-gap region of the semiconductor. It is demonstrated here that plasmon-assisted efficiency enhancements of 14.0% and 34.5% can be obtained for commercial Si and GaP solar cells, respectively, covered with Eu3+-doped TeO2-ZnO glass containing silver nanoparticles.

  16. Efficiency enhancement of octave-bandwidth TWT's by the use of multistage depressed collectors

    Science.gov (United States)

    Ramins, P.; Fox, T. A.

    1977-01-01

    A small size two and four stage depressed collector was evaluated in conjunction with a 4.8 to 9.6 GHz traveling wave tube of 325 to 675 W power output. In spite of large fixed traveling wave tube losses, very significant efficiency enhancement was demonstrated with both the two and four stage multistage depressed collectors (MDC). The improvement in the overall efficiency ranged from a factor of 2.5 to 3.0 for the two stage MDC and a factor of 3.0 to 3.5 for the four stage MDC. An overall efficiency of 37.0 to 44.3 percent across the frequency band was demonstrated with the use of harmonic injection.

  17. Enhanced continuous-wave four-wave mixing efficiency in nonlinear AlGaAs waveguides.

    Science.gov (United States)

    Apiratikul, Paveen; Wathen, Jeremiah J; Porkolab, Gyorgy A; Wang, Bohan; He, Lei; Murphy, Thomas E; Richardson, Christopher J K

    2014-11-03

    Enhancements of the continuous-wave four-wave mixing conversion efficiency and bandwidth are accomplished through the application of plasma-assisted photoresist reflow to reduce the sidewall roughness of sub-square-micron-modal area waveguides. Nonlinear AlGaAs optical waveguides with a propagation loss of 0.56 dB/cm demonstrate continuous-wave four-wave mixing conversion efficiency of -7.8 dB. Narrow waveguides that are fabricated with engineered processing produce waveguides with uncoated sidewalls and anti-reflection coatings that show group velocity dispersion of +0.22 ps²/m. Waveguides that are 5-mm long demonstrate broadband four-wave mixing conversion efficiencies with a half-width 3-dB bandwidth of 63.8-nm.

  18. Enhancing the Efficiency of Silicon-Based Solar Cells by the Piezo-Phototronic Effect.

    Science.gov (United States)

    Zhu, Laipan; Wang, Longfei; Pan, Caofeng; Chen, Libo; Xue, Fei; Chen, Baodong; Yang, Leijing; Su, Li; Wang, Zhong Lin

    2017-02-28

    Although there are numerous approaches for fabricating solar cells, the silicon-based photovoltaics are still the most widely used in industry and around the world. A small increase in the efficiency of silicon-based solar cells has a huge economic impact and practical importance. We fabricate a silicon-based nanoheterostructure (p(+)-Si/p-Si/n(+)-Si (and n-Si)/n-ZnO nanowire (NW) array) photovoltaic device and demonstrate the enhanced device performance through significantly enhanced light absorption by NW array and effective charge carrier separation by the piezo-phototronic effect. The strain-induced piezoelectric polarization charges created at n-doped Si-ZnO interfaces can effectively modulate the corresponding band structure and electron gas trapped in the n(+)-Si/n-ZnO NW nanoheterostructure and thus enhance the transport process of local charge carriers. The efficiency of the solar cell was improved from 8.97% to 9.51% by simply applying a static compress strain. This study indicates that the piezo-phototronic effect can enhance the performance of a large-scale silicon-based solar cell, with great potential for industrial applications.

  19. Enhancing stability and efficiency of perovskite solar cells with crosslinkable silane-functionalized and doped fullerene

    Science.gov (United States)

    Bai, Yang; Dong, Qingfeng; Shao, Yuchuan; Deng, Yehao; Wang, Qi; Shen, Liang; Wang, Dong; Wei, Wei; Huang, Jinsong

    2016-10-01

    The instability of hybrid perovskite materials due to water and moisture arises as one major challenge to be addressed before any practical application of the demonstrated high efficiency perovskite solar cells. Here we report a facile strategy that can simultaneously enhance the stability and efficiency of p-i-n planar heterojunction-structure perovskite devices. Crosslinkable silane molecules with hydrophobic functional groups are bonded onto fullerene to make the fullerene layer highly water-resistant. Methylammonium iodide is introduced in the fullerene layer for n-doping via anion-induced electron transfer, resulting in dramatically increased conductivity over 100-fold. With crosslinkable silane-functionalized and doped fullerene electron transport layer, the perovskite devices deliver an efficiency of 19.5% with a high fill factor of 80.6%. A crosslinked silane-modified fullerene layer also enhances the water and moisture stability of the non-sealed perovskite devices by retaining nearly 90% of their original efficiencies after 30 days' exposure in an ambient environment.

  20. Bioinformatic analysis of neurotropic HIV envelope sequences identifies polymorphisms in the gp120 bridging sheet that increase macrophage-tropism through enhanced interactions with CCR5

    Energy Technology Data Exchange (ETDEWEB)

    Mefford, Megan E., E-mail: megan_mefford@hms.harvard.edu [Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA (United States); Kunstman, Kevin, E-mail: kunstman@northwestern.edu [Northwestern University Medical School, Chicago, IL (United States); Wolinsky, Steven M., E-mail: s-wolinsky@northwestern.edu [Northwestern University Medical School, Chicago, IL (United States); Gabuzda, Dana, E-mail: dana_gabuzda@dfci.harvard.edu [Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA (United States); Department of Neurology (Microbiology and Immunobiology), Harvard Medical School, Boston, MA (United States)

    2015-07-15

    Macrophages express low levels of the CD4 receptor compared to T-cells. Macrophage-tropic HIV strains replicating in brain of untreated patients with HIV-associated dementia (HAD) express Envs that are adapted to overcome this restriction through mechanisms that are poorly understood. Here, bioinformatic analysis of env sequence datasets together with functional studies identified polymorphisms in the β3 strand of the HIV gp120 bridging sheet that increase M-tropism. D197, which results in loss of an N-glycan located near the HIV Env trimer apex, was detected in brain in some HAD patients, while position 200 was estimated to be under positive selection. D197 and T/V200 increased fusion and infection of cells expressing low CD4 by enhancing gp120 binding to CCR5. These results identify polymorphisms in the HIV gp120 bridging sheet that overcome the restriction to macrophage infection imposed by low CD4 through enhanced gp120–CCR5 interactions, thereby promoting infection of brain and other macrophage-rich tissues. - Highlights: • We analyze HIV Env sequences and identify amino acids in beta 3 of the gp120 bridging sheet that enhance macrophage tropism. • These amino acids at positions 197 and 200 are present in brain of some patients with HIV-associated dementia. • D197 results in loss of a glycan near the HIV Env trimer apex, which may increase exposure of V3. • These variants may promote infection of macrophages in the brain by enhancing gp120–CCR5 interactions.

  1. Resveratrol Co-Treatment Attenuates the Effects of HIV Protease Inhibitors on Rat Body Weight and Enhances Cardiac Mitochondrial Respiration.

    Directory of Open Access Journals (Sweden)

    Burger Symington

    Full Text Available Since the early 1990s human immunodeficiency virus (HIV/acquired immunodeficiency syndrome (AIDS emerged as a global health pandemic, with sub-Saharan Africa the hardest hit. While the successful roll-out of antiretroviral (ARV therapy provided significant relief to HIV-positive individuals, such treatment can also elicit damaging side-effects. Here especially HIV protease inhibitors (PIs are implicated in the onset of cardio-metabolic complications such as type-2 diabetes and coronary heart disease. As there is a paucity of data regarding suitable co-treatments within this context, this preclinical study investigated whether resveratrol (RSV, aspirin (ASP or vitamin C (VitC co-treatment is able to blunt side-effects in a rat model of chronic PI exposure (Lopinavir/Ritonavir treatment for 4 months. Body weights and weight gain, blood metabolite levels (total cholesterol, HDL, LDL, triglycerides, echocardiography and cardiac mitochondrial respiration were assessed in PI-treated rats ± various co-treatments. Our data reveal that PI treatment significantly lowered body weight and cardiac respiratory function while no significant changes were found for heart function and blood metabolite levels. Moreover, all co-treatments ameliorated the PI-induced decrease in body weight after 4 months of PI treatment, while RSV co-treatment enhanced cardiac mitochondrial respiratory capacity in PI-treated rats. This pilot study therefore provides novel hypotheses regarding RSV co-treatment that should be further assessed in greater detail.

  2. Efficiency enhancement in solution processed organic and organic-inorganic perovskite solar cells

    Science.gov (United States)

    Xiao, Zhengguo

    Solution processed thin film photovoltaic devices are one of the most promising renewable energy sources. Organic solar cells have been intensively studied due to their advantages of light-weight, flexibility and low-cost materials and manufacturing. The organic-inorganic hybrid perovskite materials have recently shown great potential application in solar cells. The PCE increased dramatically from 3.8% in 2009 to a certified efficiency of 20.1% in 2014. In this dissertation, we focus on the efficiency enhancement for solution processed organic and organic-inorganic solar cells. In Chapter 2, I demonstrated that the crystallinity of the ferroelectric polymer P(VDF-TrFE) at the organic active layer/ electrode interface plays a critical role in the efficiency enhancement of organic solar cells. Then, The ferroelectric P(VDF-TrFE) nanocrystals was synthesized and successfully applied in the low band gap polymers. A high efficiency of 6.8% was achieved in the PCDTBT:PCBM system. Another small polar molecule, TPACA, was also applied to increase the efficiency of organic solar cells. In Chapter 3, I developed a universal approach of solvent fluxing to fabricate graded bulk heterojunction (BHJ) polymer:fullerene films to increase the device efficiency. The solvent fluxing process can extract part of the fullerene inside the BHJ film to the top surface to form graded BHJ. The PCE of the devices after solvent fluxing is increased by 15%--50% compared with the control devices without solvent fluxing. In Chapter 5, a two-step spin coating approach was developed to fabricate the continuous and compact organolead trihalide perovskite (OTP) films. The average PCE of methylammonium lead iodide (MAPbI3) perovskite devices reached 14.5% and 85% of the devices had efficiency above 14%. In Chapter 6, I discovered that the solvent annealing can be used to increase the grain size and crystallinity of the perovskite films. The highest device efficiency reached 15.6%, and device

  3. Nef functions in BLT mice to enhance HIV-1 replication and deplete CD4+CD8+ thymocytes

    Directory of Open Access Journals (Sweden)

    Zou Wei

    2012-05-01

    Full Text Available Abstract Background The outcome of untreated HIV-1 infection is progression to AIDS and death in nearly all cases. Some important exceptions are the small number of patients infected with HIV-1 deleted for the accessory gene, nef. With these infections, disease progression is entirely suppressed or greatly delayed. Whether Nef is critical for high levels of replication or is directly cytotoxic remains controversial. The major problem in determining the role of Nef in HIV/AIDS has been the lack of tractable in vivo models where Nef’s complex pathogenic phenotype can be recapitulated. Results Intravenous inoculation (3000 to 600,000 TCIU of BLT humanized mice with HIV-1LAI reproducibly establishes a systemic infection. HIV-1LAI (LAI replicates to high levels (peak viral load in blood 8,200,000 ± 1,800,000 copies of viral RNA/ml, range 3,600,000 to 20,400,000; n = 9 and exhaustively depletes CD4+ T cells in blood and tissues. CD4+CD8+ thymocytes were also efficiently depleted but CD4+CD8- thymocytes were partially resistant to cell killing by LAI. Infection with a nef-deleted LAI (LAINefdd gave lower peak viral loads (1,220,000 ± 330,000, range 27,000 to 4,240,000; n = 17. For fourteen of seventeen LAINefdd-infected mice, there was little to no loss of either CD4+ T cells or thymocytes. Both LAI- and LAINefdd-infected mice had about 8% of total peripheral blood CD8+ T cells that were CD38+HLA-DR+ compared dd-infected mice that lost CD4+ T cells received 600,000 TCIU. All three exhibited peak viral loads over 3,000,000 copies of LAINefdd RNA/ml. Over an extended time course, substantial systemic CD4+ T cell loss was observed for the three mice, but there was no loss of CD4+CD8+ or CD4+CD8- thymocytes. Conclusion We conclude Nef is necessary for elevated viral replication and as a result indirectly contributes to CD4+ T cell killing. Further, Nef was not necessary for the activation of peripheral blood CD8+ T cells following

  4. Efficient, high rep rate, large-bore kinetically enhanced copper vapor laser with low (thermal assembly.

    Science.gov (United States)

    Singh, Bijendra; Subramaniam, V V; Daultabad, S R; Chakraborty, Ashim

    2009-10-01

    Large-bore kinetically enhanced copper vapor laser (CVL) based on new thermal assembly consisting of different density zones of insulation material (alumina fiber) around the discharge tube is demonstrated for the first time with efficiency eta > or = 1% at extremely low specific input power (SIP) of insulation material, efficiency of approximately 1.2% was achieved at lowest SIP of approximately 0.75 kW/l. Net reduction in the input power of approximately 1 kW was observed on using this thermal assembly as compared to nonprofiled thermal assembly. These results show significant improvement (25%-30%) at low input requirements of the laser on using new thermal assembly around the discharge tube with overall electro-optical efficiency eta > or = 1%. Maximum laser power achieved from the laser was approximately 78 W at approximately 9.8 kHz rep rate with efficiency of approximately 1.4%. This large-bore CVL is also capable of operating efficiently (eta approximately 1%) at high rep rate of -17 kHz with maximum laser power of approximately 50 W. Performance of the laser under various operating conditions is also presented in this short paper.

  5. Enhancement in recovery of drugs with high protein binding efficiency from human plasma using magnetic nanoparticles.

    Science.gov (United States)

    Bhati, Aniruddha; Desai, Rucha P; Ramchand, C N

    2017-09-05

    In this paper, we propose an alternate method for bioanalytical extraction of drugs from human plasma samples using bare magnetic nanoparticles. The magnetic nanoparticles (MNPs) were used for deproteination of biological samples that further assist in extraction of plasma bound drugs for bioanalytical studies. The method uses basic solvents (ethanol, methanol, etc.) rather than the expensive and toxic solvents. The MNPs provide several advantages like avoiding the use of centrifuge machine, and making extraction time effective. The average time involved for the sample preparation is around 30-40min. The developed method was examined for seven different drugs having moderate (40-70%) to high (>80%) plasma protein binding efficiency. The present study focuses on the principle of magnetic nanoparticle based extraction of drug that binds with the plasma protein. In calcitriol (protein binding efficiency >99%), it was observed that the drug extraction efficiency could be enhanced by 16% using the present method. However, we assume that still there is a scope for improving the extraction efficiency by optimizing proper solvent for the specific drug. The use of magnetic nanoparticles makes the extraction cost effective and quick with improved efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. HIV-1 infection of human intestinal lamina propria CD4+ T cells in vitro is enhanced by exposure to commensal Escherichia coli.

    Science.gov (United States)

    Dillon, Stephanie M; Manuzak, Jennifer A; Leone, Amanda K; Lee, Eric J; Rogers, Lisa M; McCarter, Martin D; Wilson, Cara C

    2012-07-15

    Microbial translocation has been linked to systemic immune activation in HIV-1 disease, yet mechanisms by which microbes may contribute to HIV-associated intestinal pathogenesis are poorly understood. Importantly, our understanding of the impact of translocating commensal intestinal bacteria on mucosal-associated T cell responses in the context of ongoing viral replication that occurs early in HIV-1 infection is limited. We previously identified commensal Escherichia coli-reactive Th1 and Th17 cells in normal human intestinal lamina propria (LP). In this article, we established an ex vivo assay to investigate the interactions between Th cell subsets in primary human LP mononuclear cells (LPMCs), commensal E. coli, and CCR5-tropic HIV-1(Bal). Addition of heat-killed E. coli to HIV-1-exposed LPMCs resulted in increases in HIV-1 replication, CD4 T cell activation and infection, and IL-17 and IFN-γ production. Conversely, purified LPS derived from commensal E. coli did not enhance CD4 T cell infection. E. coli exposure induced greater proliferation of LPMC Th17 than Th1 cells. Th17 cells were more permissive to infection than Th1 cells in HIV-1-exposed LPMC cultures, and Th17 cell infection frequencies significantly increased in the presence of E. coli. The E. coli-associated enhancement of infection was dependent on the presence of CD11c(+) LP dendritic cells and, in part, on MHC class II-restricted Ag presentation. These results highlight a potential role for translocating microbes in impacting mucosal HIV-1 pathogenesis during early infection by increasing HIV-1 replication and infection of intestinal Th1 and Th17 cells.

  7. The microvesicle component of HIV-1 inocula modulates dendritic cell infection and maturation and enhances adhesion to and activation of T lymphocytes.

    Directory of Open Access Journals (Sweden)

    Sarah K Mercier

    2013-10-01

    Full Text Available HIV-1 is taken up by immature monocyte derived dendritic cells (iMDDCs into tetraspanin rich caves from which the virus can either be transferred to T lymphocytes or enter into endosomes resulting in degradation. HIV-1 binding and fusion with the DC membrane results in low level de novo infection that can also be transferred to T lymphocytes at a later stage. We have previously reported that HIV-1 can induce partial maturation of iMDDCs at both stages of trafficking. Here we show that CD45⁺ microvesicles (MV which contaminate purified HIV-1 inocula due to similar size and density, affect DC maturation, de novo HIV-1 infection and transfer to T lymphocytes. Comparing iMDDCs infected with CD45-depleted HIV-1BaL or matched non-depleted preparations, the presence of CD45⁺ MVs was shown to enhance DC maturation and ICAM-1 (CD54 expression, which is involved in DC∶T lymphocyte interactions, while restricting HIV-1 infection of MDDCs. Furthermore, in the DC culture HIV-1 infected (p24⁺ MDDCs were more mature than bystander cells. Depletion of MVs from the HIV-1 inoculum markedly inhibited DC∶T lymphocyte clustering and the induction of alloproliferation as well as limiting HIV-1 transfer from DCs to T lymphocytes. The effects of MV depletion on these functions were reversed by the re-addition of purified MVs from activated but not non-activated SUPT1.CCR5-CL.30 or primary T cells. Analysis of the protein complement of these MVs and of these HIV-1 inocula before and after MV depletion showed that Heat Shock Proteins (HSPs and nef were the likely DC maturation candidates. Recombinant HSP90α and β and nef all induced DC maturation and ICAM-1 expression, greater when combined. These results suggest that MVs contaminating HIV-1 released from infected T lymphocytes may be biologically important, especially in enhancing T cell activation, during uptake by DCs in vitro and in vivo, particularly as MVs have been detected in the circulation of HIV-1

  8. Enhancing NGO capacity in HIV / AIDS materials development: experiences from Nepal.

    Science.gov (United States)

    Frey, M; Pyakuryal, N

    1995-07-01

    With the goal of improving the communication skills of Nepali nongovernmental organizations (NGO) involved in HIV/AIDS prevention programs and activities, Save the Children, US (SC/US) invited 12 leading NGOs in HIV/AIDS prevention to attend an information, education, and communication (IEC) workshop at the end of 1993 addressing the principles of materials development and how the groups could coordinate their activities and improve the quality of materials developed. The Nepal NGO HIV/AIDS IEC Coordination Committee resulted. 17 organizations now comprise the committee which has reviewed and commented upon 60 draft educational materials developed by member organizations and other NGOs working in more remote areas of the country. The committee has proved to be a good forum for improving materials development and distribution in Nepal and for providing technical assistance to the NGO community. NGO communication skills have increased markedly. The group has also facilitated the transfer of technical skills, coordination, and resource allocation.

  9. Efficient in vitro inhibition of HIV-1 gag reverse transcription by peptide nucleic acid (PNA) at minimal ratios of PNA/RNA

    DEFF Research Database (Denmark)

    Koppelhus, Uffe; Zachar, Vladimir; Nielsen, P.E.

    1997-01-01

    We have tested the inhibitory potential of peptide nucleic acid (PNA) on in vitro reverse transcription of the HIV-1 gag gene. PNA was designed to target different regions of the HIV-1 gag gene and the effect on reverse transcription by HIV-1, MMLV and AMV reverse transcriptases (RTs...... that would indicate PNA-mediated RNase H activation of the tested RTs. In conclusion, PNA appears to have a potential to become a specific and efficient inhibitor of reverse transcription in vivo , provided sufficient intracellular levels are achievable.......) was investigated. We found that a bis-PNA (parallel antisense 10mer linked to antiparallel antisense 10mer) was superior to both the parallel antisense 10mer and antiparallel antisense 10mer in inhibiting reverse transcription of the gene, thus indicating triplex formation at the target sequence. A complete arrest...

  10. Ionizing and ultraviolet radiation enhances the efficiency of DNA mediated gene transfer in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Perez, C.F.

    1984-08-01

    The enhancement effects of ionizing and non-ionizing radiation on the efficiency of DNA mediated gene transfer were studied. Confluent Rat-2 cells were transfected with purified SV40 viral DNA, irradiated with either X-rays or ultraviolet, trypsinized, plated, and assayed for the formation of foci on Rat-2 monolayers. Both ionizing and ultraviolet radiation enhanced the frequency of A-gene transformants/survivor compared to unirradiated transfected cells. These enhancements were non-linear and dose dependent. A recombinant plasmid, pOT-TK5, was constructed that contained the SV40 virus A-gene and the Herpes Simplex virus (HSV) thymidine kinase (TK) gene. Confluent Rat-2 cells transfected with pOT-TK5 DNA and then immediately irradiated with either X-rays or 330 MeV/amu argon particles at the Berkeley Bevalac showed a higher frequency of HAT/sup +/ colonies/survivor than unirradiated transfected cells. Rat-2 cells transfected with the plasmid, pTK2, containing only the HSV TK-gene were enhanced for TK-transformation by both X-rays and ultraviolet radiation. The results demonstrate that radiation enhancement of the efficiency of DNA mediated gene transfer is not explained by increased nuclear uptake of the transfected DNA. Radiation increases the competence of the transfected cell population for genetic transformation. Three models for this increased competence are presented. The targeted integration model, the inducible recombination model, the partition model, and the utilization of DNA mediated gene transfer for DNA repair studies are discussed. 465 references.

  11. Interferon-alpha administration enhances CD8+ T cell activation in HIV infection.

    Directory of Open Access Journals (Sweden)

    Maura Manion

    Full Text Available Type I interferons play important roles in innate immune defense. In HIV infection, type I interferons may delay disease progression by inhibiting viral replication while at the same time accelerating disease progression by contributing to chronic immune activation.To investigate the effects of type I interferons in HIV-infection, we obtained cryopreserved peripheral blood mononuclear cell samples from 10 subjects who participated in AIDS Clinical Trials Group Study 5192, a trial investigating the activity of systemic administration of IFNα for twelve weeks to patients with untreated HIV infection. Using flow cytometry, we examined changes in cell cycle status and expression of activation antigens by circulating T cells and their maturation subsets before, during and after IFNα treatment.The proportion of CD38+HLA-DR+CD8+ T cells increased from a mean of 11.7% at baseline to 24.1% after twelve weeks of interferon treatment (p = 0.006. These frequencies dropped to an average of 20.1% six weeks after the end of treatment. In contrast to CD8+ T cells, the frequencies of activated CD4+ T cells did not change with administration of type I interferon (mean percentage of CD38+DR+ cells = 2.62% at baseline and 2.17% after 12 weeks of interferon therapy. As plasma HIV levels fell with interferon therapy, this was correlated with a "paradoxical" increase in CD8+ T cell activation (p<0.001.Administration of type I interferon increased expression of the activation markers CD38 and HLA DR on CD8+ T cells but not on CD4+ T cells of HIV+ persons. These observations suggest that type I interferons may contribute to the high levels of CD8+ T cell activation that occur during HIV infection.

  12. Optimization of the enhanced membrane coagulation reactor for sewage concentration efficiency and energy recovery.

    Science.gov (United States)

    Odey, Emmanuel Alepu; Wang, Kaijun; Li, Zifu; Gao, Ruiling; Etokidem, Esther Uduak; Jin, Zhengyu

    2017-09-16

    The application of an enhanced membrane coagulation reactor (E-MCR) for sewage concentration and energy recovery through anaerobic digestion (AD) was investigated. The results show that the addition of powder-activated carbon (PAC) and polyaluminum chloride (PACl) enhanced the sewage concentration efficiency and minimized the membrane fouling. The reactor was operated for 100 d with 70 d without severe fouling. The flux of 6 L/(m(2) h) with sludge retention time of 2 d recorded a long-term stable performance and recovered concentrates with about 6000-9800 mg/L of chemical oxygen demand (COD) values. The concentrate was used as feed for AD using a continuous stirred tank reactor. The results show that at a thermophilic temperature of 35°C, a high biogas yield was achieved at 20 and 30 d hydraulic retention time (HRT). Meanwhile, biogas yields of 10, 220, and 295 mL/(gCOD) were achieved at 10, 20, and 30 d HRT, respectively. The addition of PAC/PACl and the low flux condition enhanced the concentration efficiency and minimized the membrane fouling during the long-term operation. Thus, with the optimization of the operation, E-MCR becomes a promising option for sewage concentration and energy recovery.

  13. Specialization versus adaptation: two strategies employed by cyanophages to enhance their translation efficiencies.

    Science.gov (United States)

    Limor-Waisberg, Keren; Carmi, Asaf; Scherz, Avigdor; Pilpel, Yitzhak; Furman, Itay

    2011-08-01

    Effective translation of the viral genome during the infection cycle most likely enhances its fitness. In this study, we reveal two different strategies employed by cyanophages, viruses infecting cyanobacteria, to enhance their translation efficiency. Cyanophages of the T7-like Podoviridae family adjust their GC content and codon usage to those of their hosts. In contrast, cyanophages of the T4-like Myoviridae family maintain genomes with low GC content, thus sometimes differing from that of their hosts. By introducing their own specific set of tRNAs, they appear to modulate the tRNA pools of hosts with tRNAs that fit the viral low GC preferred codons. We assessed the possible effects of those viral tRNAs on cyanophages and cyanobacterial genomes using the tRNA adaptation index, which measures the extent to which a given pool of tRNAs translates efficiently particular genes. We found a strong selective pressure to gain and maintain tRNAs that will boost translation of myoviral genes when infecting a high GC host, contrasted by a negligible effect on the host genes. Thus, myoviral tRNAs may represent an adaptive strategy to enhance fitness when infecting high GC hosts, thereby potentially broadening the spectrum of hosts while alleviating the need to adjust global parameters such as GC content for each specific host.

  14. Prescribing restrictions – a necessary strategy among some European countries to enhance future prescribing efficiency?

    Directory of Open Access Journals (Sweden)

    Brian Godman

    2012-01-01

    Full Text Available The unsustainable growth in pharmaceutical expenditure has resulted in multiple initiatives across Europe to lower prices of generics and enhance their utilisation. These include prescribing restrictions. However, there have been concerns with their impact on subsequent quality of care as well as their influence in reality. OBJECTIVES: (a Review the influence of prescribing restrictions and whether there are any differences depending on their nature and drug classes; (b Ascertain whether prescribing restrictions can be added to existing demand-side measures to further enhance prescribing efficiency; (c Whether they compromise subsequent quality of care. RESULTS: Prescribing restrictions have a variable impact on subsequent utilisation of patented protected products versus generics in a class, with their influence depending on the nature and follow-up of the restrictions rather than the class of drug. This is seen among the proton pump inhibitors, statins, and renin-angiotensin drugs. Prescribing restrictions can be successfully added to existing measures to further enhance prescribing efficiency, and do not appear to compromise subsequent quality of care. CONCLUSIONS: Prescribing restrictions can be a successful strategy as countries strive to maintain the European ideals for healthcare. However, care is needed when planning these programmes: else health authorities could be disappointed with their outcome.

  15. Enhanced diffraction efficiency of mixed volume gratings with nanorod dopants in polymeric nanocomposite

    Science.gov (United States)

    Cao, Liangcai; Wu, Shenghan; Hao, Jinping; Zhu, Chen; He, Zehao; Zhang, Zheyuan; Zong, Song; Zhang, Fushi; Jin, Guofan

    2017-10-01

    We propose a method to improve the holographic performance of a volume holographic material by the particle-shape dependence of doped nanoparticles. Previously reported methods are based on changing the doping concentration of dopants and the diameter of nanoparticles or modifying the surface of nanoparticles. When transverse surface plasmon resonance of optimized gold nanorods shifts near the recording wavelength, experiments confirmed that enhancement of diffraction efficiency by efficient dopants of gold nanorods is better than that of gold nanospheres. The enhancement effects under optimal mixing conditions occur with a crucial factor of maximum absorption intensity at the recording wavelength using the particle-shape dependence of doping nanorods. The gold nanorods with an average diameter of 10 ± 2.1 nm and an average length of 34 ± 5 nm are doped in Phenanthrenequinone-doped poly(methyl methacrylate) photopolymers. The diffraction efficiency of volume holographic grating in the photopolymer doped with nanorods is 18.5% higher than that in the photopolymer doped with nanospheres and 29.6% higher than that in the pure photopolymer.

  16. RS-1 enhances CRISPR/Cas9- and TALEN-mediated knock-in efficiency.

    Science.gov (United States)

    Song, Jun; Yang, Dongshan; Xu, Jie; Zhu, Tianqing; Chen, Y Eugene; Zhang, Jifeng

    2016-01-28

    Zinc-finger nuclease, transcription activator-like effector nuclease and CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated protein 9) are becoming major tools for genome editing. Importantly, knock-in in several non-rodent species has been finally achieved thanks to these customizable nucleases; yet the rates remain to be further improved. We hypothesize that inhibiting non-homologous end joining (NHEJ) or enhancing homology-directed repair (HDR) will improve the nuclease-mediated knock-in efficiency. Here we show that the in vitro application of an HDR enhancer, RS-1, increases the knock-in efficiency by two- to five-fold at different loci, whereas NHEJ inhibitor SCR7 has minimal effects. We then apply RS-1 for animal production and have achieved multifold improvement on the knock-in rates as well. Our work presents tools to nuclease-mediated knock-in animal production, and sheds light on improving gene-targeting efficiencies on pluripotent stem cells.

  17. Multiscale Modeling of Plasmon-Enhanced Power Conversion Efficiency in Nanostructured Solar Cells.

    Science.gov (United States)

    Meng, Lingyi; Yam, ChiYung; Zhang, Yu; Wang, Rulin; Chen, GuanHua

    2015-11-05

    The unique optical properties of nanometallic structures can be exploited to confine light at subwavelength scales. This excellent light trapping is critical to improve light absorption efficiency in nanoscale photovoltaic devices. Here, we apply a multiscale quantum mechanics/electromagnetics (QM/EM) method to model the current-voltage characteristics and optical properties of plasmonic nanowire-based solar cells. The QM/EM method features a combination of first-principles quantum mechanical treatment of the photoactive component and classical description of electromagnetic environment. The coupled optical-electrical QM/EM simulations demonstrate a dramatic enhancement for power conversion efficiency of nanowire solar cells due to the surface plasmon effect of nanometallic structures. The improvement is attributed to the enhanced scattering of light into the photoactive layer. We further investigate the optimal configuration of the nanostructured solar cell. Our QM/EM simulation result demonstrates that a further increase of internal quantum efficiency can be achieved by scattering light into the n-doped region of the device.

  18. Charge carrier trapping and enhanced electroluminescent efficiency of blue light emitting polymer with gold nanoparticles.

    Science.gov (United States)

    Park, Jong Hyeok; Choi, Yu-Ri; Chin, Byung Doo

    2009-12-01

    We investigated the current injection, transport, and luminous efficiency behavior of organic light emitting diode (OLED) containing the 5-10 nm-sized gold particles mixed in the polyfluorene-type copolymer. This nanoparticle-conjugated polymer mixture layer was used as hole injection, transport, and light emitting layer for various structures of OLED based on the phosphorescent and fluorescent emitters. Due to the hole trapping at the nanopaticle, carrier injection is significantly reduced while the hole transport behavior is found to be barely affected. Hole trapping of nanoparticle in light emitting layer (at 4.7 approximately 9.4 x 10(-5) w/w fraction) resulted in an enhancement of efficiency (from 5.23 cd/A to 6.50 cd/A). The existence of the outcoupling effect also supports the carrier trapping behavior, which is amended mechanism of the improved efficiency compared to previously reported mechanism of enhanced photoluminescent stability by a hindrance of photo-oxidation.

  19. Improved Efficiency of Miscible C02 Floods and Enhanced Prospects for C02 Flooding Heterogeneous Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Boyun (Gordon) Guo; David S. Schechter; Jyun-Syung Tsau; Reid B. Grigg; Shih-Hsien (Eric) Chang

    1997-01-23

    A grant, �Improved Efficiency of Miscible CO2 Floods and Enhanced Prospects for CO2 Flooding Heterogeneous Reservoirs,� DOE Contract No. DE-FG26-97BC15047, was awarded and started on June 1, 1997. This project examines three major areas in which CO2 flooding can be improved: fluid and matrix interactions, conformance control/sweep efficiency, and reservoir simulation for improved oil recovery. In this quarter we continued the examination of synergistic effects of mixed surfactant versus single surfactant systems to enhance the properties of foams used for improving oil recovery in CO2 floods. The purpose is to reduce the concentration of surfactants and find less expensive surfactants. Also, we are refining reservoir models to handle the complex relationships of CO2-foam and heterogeneous reservoirs. The third area of our report this quarter comprises the results from experiments on CO2-assisted gravity drainage in naturally fractured oil reservoirs. Two more CO2 core flood experiments have been conducted under reservoir conditions to investigate the effect of pressure on oil recovery efficiency during CO2-assisted gravity drainage.

  20. Enhancing Scalability and Efficiency of the TOUGH2_MP for LinuxClusters

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Keni; Wu, Yu-Shu

    2006-04-17

    TOUGH2{_}MP, the parallel version TOUGH2 code, has been enhanced by implementing more efficient communication schemes. This enhancement is achieved through reducing the amount of small-size messages and the volume of large messages. The message exchange speed is further improved by using non-blocking communications for both linear and nonlinear iterations. In addition, we have modified the AZTEC parallel linear-equation solver to nonblocking communication. Through the improvement of code structuring and bug fixing, the new version code is now more stable, while demonstrating similar or even better nonlinear iteration converging speed than the original TOUGH2 code. As a result, the new version of TOUGH2{_}MP is improved significantly in its efficiency. In this paper, the scalability and efficiency of the parallel code are demonstrated by solving two large-scale problems. The testing results indicate that speedup of the code may depend on both problem size and complexity. In general, the code has excellent scalability in memory requirement as well as computing time.

  1. Enhancing HIV Prevention Among Young Men Who Have Sex With Men: A Systematic Review of HIV Behavioral Interventions for Young Gay and Bisexual Men.

    Science.gov (United States)

    Hergenrather, Kenneth C; Emmanuel, Diona; Durant, Sarah; Rhodes, Scott D

    2016-06-01

    Men who have sex with men (MSM) represent 64.0% of people living with HIV (PLWH) over the age of 13 years. Young men who have sex with men (YMSM) are particularly affected by HIV/AIDS; the rate of HIV infection for YMSM between the ages of 13 and 24 represents 72.0% of new infections among youth. To understand the current state of the science meant to prevent HIV for YMSM, we reviewed studies of HIV behavioral prevention interventions for YMSM. Five literature databases were searched, from their inception through October 2015, using key words associated with HIV prevention intervention evaluation studies for YMSM. The review criteria included behavioral HIV/AIDS prevention interventions, articles published in English-language peer-reviewed journals, YMSM between 13 and 24 years of age, and longitudinal repeated measures design. A total of 15 YMSM behavioral HIV prevention intervention studies were identified that met inclusion criteria and reported statistically significant findings. Common outcomes included unprotected sexual intercourse, HIV/AIDS risk behavior, condom use, HIV testing, safer sex attitude, and HIV prevention communication. Participant age, representation of Black/African American YMSM, application of theoretical and model underpinnings, congruence of assessment measures used, follow-up assessment times, and application of process evaluation were inconsistent across studies. To advance HIV prevention intervention research for YMSM, future studies should be theory-based, identify common constructs, utilize standard measures, include process evaluation, and evaluate sustained change over standard periods of time. HIV prevention interventions should incorporate the needs of the diverse, well-educated, web-connected millennial generation and differentiate between adolescent YMSM (13 to 18 years of age) and young adulthood YMSM (19 to 24 years of age). Because Black/African American YMSM represent more than 50% of new HIV infections, future HIV

  2. HIV controllers exhibit enhanced frequencies of major histocompatibility complex class II tetramer+ Gag-specific CD4+ T cells in chronic clade C HIV-1 infection

    DEFF Research Database (Denmark)

    Laher, Faatima; Ranasinghe, Srinika; Porichis, Filippos

    2017-01-01

    = 0.0001), and these expanded Gag-specific CD4+ T cells in HIV controllers showed higher levels of expression of the cytolytic proteins granzymes A and B. Importantly, targeting of the immunodominant Gag41 peptide in the context of HLA class II DRB1*1101 was associated with HIV control (r = -0.5, P......Immune control of viral infections is heavily dependent on helper CD4+ T cell function. However, the understanding of the contribution of HIV-specific CD4+ T cell responses to immune protection against HIV-1, particularly in clade C infection, remains incomplete. Recently, major histocompatibility......, and then used these to define the magnitude, function, and relation to the viral load of HIV-specific CD4+ T cell responses in a cohort of untreated HIV clade C-infected persons. We observed significantly higher frequencies of MHC class II tetramer-positive CD4+ T cells in HIV controllers than progressors (P...

  3. P. falciparum Enhances HIV Replication in an Experimental Malaria Challenge System: e39000

    National Research Council Canada - National Science Library

    Marika Orlov; Florin Vaida; Olivia C Finney; David M Smith; Angela K Talley; Ruobing Wang; Stefan H Kappe; Qianqian Deng; Robert T Schooley; Patrick E Duffy

    2012-01-01

    ... naïve volunteers experimentally infected with P. falciparum in a malaria challenge trial.PBMCs collected before the malaria challenge and at several time points post-infection were infected with HIV-1 and co-cultured with either P...

  4. Responding to Changes in HIV Policy: Updating and Enhancing the "Families Matter!" Curriculum

    Science.gov (United States)

    Miller, Kim S; Winskell, Kate; Berrier, Faith L

    2016-01-01

    Objectives: The past decade has seen changes in US HIV policy in sub-Saharan Africa in response to a new Administration and far-reaching technical, scientific and programmatic developments. These include dramatically increased access to life-saving anti-retroviral therapy (ART) and related services, the roll-out of voluntary medical male…

  5. HIV/AIDS Infected Mothers' Experience of a Group Intervention to Enhance Their Children's Behavior

    Science.gov (United States)

    Eloff, Irma; Finestone, Michelle; Forsyth, Brian

    2016-01-01

    A secondary study was conducted within a broader National Institutes of Health (NIH)-funded longitudinal study on resilience in South African mothers and children affected by HIV/AIDS (Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome). The aim of this study was to evaluate the effect of a 24-week support group intervention…

  6. Laser contrast and other key parameters enhancing the laser conversion efficiency in ion acceleration regime

    Science.gov (United States)

    Torrisi, Lorenzo

    2018-01-01

    Measurements of ion acceleration in plasma produced by fs lasers at intensity of the order of 1018 W/cm2 have been performed in different European laboratories. The forward emission in target-normal-sheath-acceleration (TNSA) regime indicated that the maximum energy is a function of the laser parameters, of the irradiation conditions and of the target properties.In particular the laser intensity and contrast play an important role to maximize the ion acceleration enhancing the conversion efficiency. Also the use of suitable prepulses, focal distances and polarized laser light has important roles. Finally the target composition, surface, geometry and multilayered structure, permit to enhance the electric field driving the forward ion acceleration.Experimental measurements will be reported and discussed.

  7. Novel fungal consortium pretreatment of waste oat straw to enhance economic and efficient biohydrogen production

    Directory of Open Access Journals (Sweden)

    Lirong Zhou

    2016-12-01

    Full Text Available Bio-pretreatment using a fungal consortium to enhance the efficiency of lignocellulosic biohydrogen production was explored.  A fungal consortium comprised of T. viride and P. chrysosporium as microbial inoculum was compared with untreated and single-species-inoculated samples. Fungal bio-pretreatment was carried out at atmospheric conditions with limited external energy input.  The effectiveness of the pretreatment is evaluated according to its lignin removal and digestibility. Enhancement of biohydrogen production is observed through scanning electron microscopy (SEM analysis. Fungal consortium pretreatment effectively degraded oat straw lignin (by >47% in 7 days leading to decomposition of cell-wall structure as revealed in SEM images, increasing biohydrogen yield. The hydrogen produced from the fungal consortium pretreated straw increased by 165% 6 days later, and was more than produced from either a single fungi species of T. viride or P. chrysosponium pretreated straw (94% and 106%, respectively. No inhibitory effect on hydrogen production was observed.

  8. Enhanced Locomotion Efficiency of a Bio-inspired Walking Robot using Contact Surfaces with Frictional Anisotropy

    DEFF Research Database (Denmark)

    Manoonpong, Poramate; Petersen, Dennis; Kovalev, Alexander

    2016-01-01

    Based on the principles of morphological computation, we propose a novel approach that exploits the interaction between a passive anisotropic scale-like material (e.g., shark skin) and a non-smooth substrate to enhance locomotion efficiency of a robot walking on inclines. Real robot experiments...... show that passive tribologically-enhanced surfaces of the robot belly or foot allow the robot to grip on specific surfaces and move effectively with reduced energy consumption. Supplementing the robot experiments, we investigated tribological properties of the shark skin as well as its mechanical...... robot locomotion but also provides a better understanding of the functionalities and mechanical properties of anisotropic surfaces. That understanding will assist developing new types of material for other real-world applications....

  9. Enhanced quantum efficiency for CsI grown on a graphite-based substrate coating

    CERN Document Server

    Friese, J; Homolka, J; Kastenmüller, A; Maier-Komor, P; Peter, M; Zeitelhack, K; Kienle, P; Körner, H J

    1999-01-01

    Quantum efficiencies (QE) in the vacuum ultraviolet (VUV) wavelength region have been measured for solid CsI layers on various substrates. The CsI films were deposited applying electron beam evaporation. The QE measurements were performed utilizing synchrotron radiation as well as light from a deuterium lamp. A GaAsP diode with a sensitivity calibration traceable to a primary radiation standard was used for normalization. For CsI layers grown on resin-stabilized graphite films a significant enhancement of QE was observed. Substrates suitable for gas detector applications and aging properties were investigated. The procedures to prepare and reproduce high quantum efficient CsI layers are described.

  10. Enhancement of mosquito trapping efficiency by using pulse width modulated light emitting diodes

    Science.gov (United States)

    Liu, Yu-Nan; Liu, Yu-Jen; Chen, Yi-Chian; Ma, Hsin-Yi; Lee, Hsiao-Yi

    2017-01-01

    In this study, a light-driving bug zapper is presented for well controlling the diseases brought by insects, such as mosquitoes. In order to have the device efficient to trap the insect pests in off-grid areas, pulse width modulated light emitting diodes (PWM-LED) combined with a solar power module are proposed and implemented. With specific PWM electric signals to drive the LED, it is found that no matter what the ability of catching insects or the consumed power efficiency can be enhanced thus. It is demonstrated that 40% of the UV LED consumed power and 25.9% of the total load power consumption can be saved, and the trapped mosquitoes are about 250% increased when the PWM method is applied in the bug zapper experiments.

  11. Efficient Video Transcoding from H.263 to H.264/AVC Standard with Enhanced Rate Control

    Directory of Open Access Journals (Sweden)

    Nguyen Viet-Anh

    2006-01-01

    Full Text Available A new video coding standard H.264/AVC has been recently developed and standardized. The standard represents a number of advances in video coding technology in terms of both coding efficiency and flexibility and is expected to replace the existing standards such as H.263 and MPEG-1/2/4 in many possible applications. In this paper we investigate and present efficient syntax transcoding and downsizing transcoding methods from H.263 to H.264/AVC standard. Specifically, we propose an efficient motion vector reestimation scheme using vector median filtering and a fast intraprediction mode selection scheme based on coarse edge information obtained from integer-transform coefficients. Furthermore, an enhanced rate control method based on a quadratic model is proposed for selecting quantization parameters at the sequence and frame levels together with a new frame-layer bit allocation scheme based on the side information in the precoded video. Extensive experiments have been conducted and the results show the efficiency and effectiveness of the proposed methods.

  12. Preparing the Gut with Antibiotics Enhances Gut Microbiota Reprogramming Efficiency by Promoting Xenomicrobiota Colonization

    Directory of Open Access Journals (Sweden)

    Shou K. Ji

    2017-06-01

    Full Text Available Gut microbiota plays multiple important roles in intestinal and physiological homeostasis, and using fecal microbiota transplantation (FMT to reprogram gut microbiota has demonstrated promise for redressing intestinal and physiological disorders. This study tested the alterations in reprogramming efficiency caused by different gut preparation procedures and explored the associated underlying mechanisms. We prepared the guts of mice for FMT by administering one of the three most-clinically used pretreatments [antibiotics, bowel cleansing (BC solution, or no pretreatment], and we found that preparing the gut with antibiotics induced a more efficient modification of the gut bacterial community than was induced by either of the other two pretreatment types. The increased efficiency of antibiotic treatment appeared to occur via increasing the xenomicrobiota colonization. Further analysis demonstrated that antibiotic treatment of mice induced intestinal microbiota disruption, mostly by expelling antibiotic-sensitive bacteria, while the indigenous microbiota was maintained after treatment with a BC solution or in the absence of pretreatment. The amount of antibiotic-resistant bacteria increased shortly after antibiotics usage but subsequently decreased after FMT administration. Together, these results suggest that FMT relied on the available niches in the intestinal mucosa and that preparing the gut with antibiotics facilitated xenomicrobiota colonization in the intestinal mucosa, which thus enhanced the overall gut microbiota reprogramming efficiency.

  13. An Enhanced Light-Load Efficiency Step Down Regulator with Fine Step Frequency Scaling.

    Science.gov (United States)

    Anabtawi, Nijad; Ferzli, Rony; Harmanani, Haidar M

    2016-05-01

    This paper presents a switching DC-DC Buck converter with enhanced light-load efficiency for use in noise-sensitive applications. Low noise, spur free operation is achieved by using a sigma-delta-modulator (ΣΔ) based controller, while light load efficiency is realized through the introduction of fine step frequency scaling (FSFS) which continuously adjusts the switching frequency of the converter with load conditions. Regulation efficiency is further improved by adoption of mode hopping (continuous conduction mode (CCM)/discontinuous conduction mode (DCM)) and utilization of a fully digital implementation. Furthermore, the presented converter maintains low output voltage ripple across its entire load range by reconfiguring the ΣΔ modulator's quantization step and introducing dither to the loop filter. The proposed modulator was implemented in 14nm bulk CMOS process and validated with post layout simulations. It attains a peak efficiency of 95% at heavy load conditions and 79% at light loads with a maximum voltage ripple of 15mV at light loads.

  14. Efficiency improvements of silicon solar cells by absorption enhancement with germanium

    Energy Technology Data Exchange (ETDEWEB)

    Borne, E.; Boyeaux, J.P.; Laugier, A. [Inst. National des Sciences Appliquees, Villeurbanne (France). Lab. de Physique de la Matiere

    1994-12-31

    This paper presents a theoretical investigation of the germanium effect on the absorption coefficient in polycrystalline silicon alloys to improve solar cell efficiency. The underlying objective is to enhance the efficiency or reduce the cell thickness of the standard photovoltaic system for terrestrial application without sacrificing the benefits of the well known silicon cell technology. The study is based on the comparison of a standard polycrystalline Si cell (taken as reference) and the same cell with 8% atomic of germanium. The Si and SiGe material was processed by an extension of the POLIX method, and samples were characterized by infrared spectroscopy in the near infrared range. The authors find an optical absorption gain three times greater for Si{sub 0.92}Ge{sub 0.08} as compared to Si. Parameters of each cell are taken to be equal except for the absorption coefficient in the infrared range. The authors show, as a result of computer device modeling, that significant gains in cell efficiencies can be obtained. They have also studied the influence of the Si{sub 0.92}Ge{sub 0.08} cell thickness, and half the thickness shows an efficiency still greater than the reference Si cell.

  15. Rigid aromatic linking moiety in cationic lipids for enhanced gene transfection efficiency.

    Science.gov (United States)

    Wang, Bing; Zhao, Rui-Mo; Zhang, Ji; Liu, Yan-Hong; Huang, Zheng; Yu, Qing-Ying; Yu, Xiao-Qi

    2017-08-18

    Although numerous cationic lipids have been developed as non-viral gene vectors, the structure-activity relationship (SAR) of these materials remains unclear and needs further investigation. In this work, a series of lysine-derived cationic lipids containing linkages with different rigidity were designed and synthesized. SAR studies showed that lipids with rigid aromatic linkage could promote the formation of tight liposomes and enhance DNA condensation, which is essential for the gene delivery process. These lipids could give much higher transfection efficiency than those containing more flexible aliphatic linkage in various cell lines. Moreover, the rigid aromatic linkage also affords the material higher serum tolerance ability. Flow cytometry assay revealed that the target lipids have good cellular uptake, while confocal microscopy observation showed weaker endosome escape than Lipofectamine 2000. To solve such problem and further increase the transfection efficiency, some lysosomotropic reagents were used to improve the endosome escape of lipoplex. As expected, higher transfection efficiency than Lipofectamine 2000 could be obtained via this strategy. Cytotoxicity assay showed that these lipids have lower toxicity in various cell lines than Lipofectamine 2000, suggesting their potential for further application. This work demonstrates that a rigid aromatic linkage might distinctly improve the gene transfection abilities of cationic lipids and affords information to construct safe and efficient gene vector towards practical application. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  16. Glycosylphosphatidylinositol-Anchored Anti-HIV scFv Efficiently Protects CD4 T Cells from HIV-1 Infection and Deletion in hu-PBL Mice.

    Science.gov (United States)

    Ye, Chaobaihui; Wang, Weiming; Cheng, Liang; Li, Guangming; Wen, Michael; Wang, Qi; Zhang, Qing; Li, Dan; Zhou, Paul; Su, Lishan

    2017-02-01

    Despite success in viral inhibition and CD4 T cell recovery by highly active antiretroviral treatment (HAART), HIV-1 is still not curable due to the persistence of the HIV-1 reservoir during treatment. One patient with acute myeloid leukemia who received allogeneic hematopoietic stem cell transplantation from a homozygous CCR5 Δ32 donor has had no detectable viremia for 9 years after HAART cessation. This case has inspired a field of HIV-1 cure research focusing on engineering HIV-1 resistance in permissive cells. Here, we employed a glycosylphosphatidylinositol (GPI)-scFv X5 approach to confer resistance of human primary CD4 T cells to HIV-1. We showed that primary CD4 T cells expressing GPI-scFv X5 were resistant to CCR5 (R5)-, CXCR4 (X4)-, and dual-tropic HIV-1 and had a survival advantage compared to control cells ex vivo In a hu-PBL mouse study, GPI-scFv X5-transduced CD4 T cells were selected in peripheral blood and lymphoid tissues upon HIV-1 infection. Finally, GPI-scFv X5-transduced CD4 T cells, after being cotransfused with HIV-infected cells, showed significantly reduced viral loads and viral RNA copy numbers relative to CD4 cells in hu-PBL mice compared to mice with GPI-scFv AB65-transduced CD4 T cells. We conclude that GPI-scFv X5-modified CD4 T cells could potentially be used as a genetic intervention against both R5- and X4-tropic HIV-1 infections. Blocking of HIV-1 entry is one of most promising approaches for therapy. Genetic disruption of the HIV-1 coreceptor CCR5 by nucleases in T cells is under 2 clinical trials and leads to reduced viremia in patients. However, the emergence of viruses using the CXCR4 coreceptor is a concern for therapies applying single-coreceptor disruption. Here, we report that HIV-1-permissive CD4 T cells engineered with GPI-scFv X5 are resistant to R5-, X4-, or dual-tropic virus infection ex vivo In a preclinical study using hu-PBL mice, we show that CD4 T cells were protected and that GPI-scFv X5-transduced cells were

  17. An aptamer cocktail-functionalized photocatalyst with enhanced antibacterial efficiency towards target bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Song, Min Young [Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792 (Korea, Republic of); Jurng, Jongsoo [Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792 (Korea, Republic of); Department of Energy and Environmental Engineering, University of Science and Technology (UST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792 (Korea, Republic of); Park, Young-Kwon [School of Environmental Engineering, University of Seoul, Seoulsiripdae-ro 163, Dongdaemun-gu, Seoul 02504 (Korea, Republic of); Kim, Byoung Chan, E-mail: bchankim@kist.re.kr [Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792 (Korea, Republic of); Department of Energy and Environmental Engineering, University of Science and Technology (UST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792 (Korea, Republic of)

    2016-11-15

    Highlights: • Aptamer-conjugated TiO{sub 2} was developed for target-specific bacterial inactivation. • TiO{sub 2}-aptamer cocktail can enhance inactivation of target bacteria faster than TiO{sub 2}. • TiO{sub 2}-aptamer cocktail can enhance inactivation of target bacteria in mixed culture. • Efficient ROS transfer to the bacteria is caused by close contact of TiO{sub 2}-aptamer. - Abstract: We developed TiO{sub 2} particles conjugated with an Escherichia coli surface-specific ssDNA aptamer cocktail (composed of three different aptamers isolated from E. coli) for targeted and enhanced disinfection of E. coli. We examined the target-specific and enhanced inactivation of this composite (TiO{sub 2}-Apc), which were compared to those of TiO{sub 2} conjugated with a single aptamer (one of the three different aptamers, TiO{sub 2}-Aps) and non-modified TiO{sub 2}. We found that TiO{sub 2}-Apc enhanced the inactivation of targeted E. coli under UV irradiation compared to both the non-modified TiO{sub 2} and TiO{sub 2}-Aps. A higher number of TiO{sub 2}-Apc than TiO{sub 2}-Aps particles was observed on the surface of E. coli. The amount of TiO{sub 2}-Apc required to inactivate ∼99.9% of E. coli (10{sup 6} CFU/ml) was 10 times lower than that of non-modified TiO{sub 2}. The close proximity of functionalized particles with E. coli resulting from the interaction between the target surface and the aptamer induced the efficient and fast transfer of reactive oxygen species to the cells. In a mixed culture of different bacteria (E. coli and Staphylococcus epidermidis), TiO{sub 2}-Apc enhanced the inactivation of only E. coli. Taken together, these results support the use of aptamer cocktail-conjugated TiO{sub 2} for improvement of the target-specific inactivation of bacteria.

  18. Carbohydrate-binding agents efficiently prevent dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN)-directed HIV-1 transmission to T lymphocytes.

    Science.gov (United States)

    Balzarini, Jan; Van Herrewege, Yven; Vermeire, Kurt; Vanham, Guido; Schols, Dominique

    2007-01-01

    Exposure of HIV-1 to dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN)-expressing B-lymphoblast Raji cells (Raji/DC-SIGN) but not to wild-type Raji/0 cells results in the capture of HIV-1 particles to the cells as measured by the quantification of cell-associated p24 antigen. Cocultivation of HIV-1-captured Raji/DC-SIGN cells with uninfected CD4+ T lymphocyte C8166 cells results in abundant formation of syncytia within 36 h after cocultivation. Short preexposure of HIV-1 to carbohydrate-binding agents (CBA) dose dependently prevents the Raji/DC-SIGN cells from efficiently binding the virus particles, and no syncytia formation occurs upon subsequent cocultivation with C8166 cells. Thus, the mannose-specific [i.e., the plant lectins Hippeastrum hybrid agglutinin (HHA), Galanthus nivalis agglutinin (GNA), Narcissus pseudonarcissus agglutinin; and Cymbidium agglutinin (CA); the procaryotic cyanovirin-N (CV-N); and the monoclonal antibody 2G12) and N-acetylglucosamine-specific (i.e., the plant lectin Urtica dioica agglutinin) CBAs efficiently abrogate the DC-SIGN-directed HIV-1 capture and subsequent transmission to T lymphocytes. In this assay, the CD4-down-regulating cyclotriazodisulfonamide derivative, the CXCR4 and CCR5 coreceptor antagonists 1-[[4-(1,4,8,11-tetrazacyclotetradec-1-ylmethyl)phenyl]methyl] - 1,4,8,11 - tetrazacyclotetradecane (AMD3100) and maraviroc, the gp41-binding enfuvirtide, and the polyanionic substances dextran sulfate (M(r) 5000), sulfated polyvinyl alcohol, and the naphthalene sulfonate polymer PRO-2000 were markedly less efficient or even completely ineffective. Similar observations were made in primary monocyte-derived dendritic cell cultures that were infected with HIV-1 particles that had been shortly pre-exposed to the CBAs CV-N, CA, HHA, and GNA and the polyanions DS-5000 and PRO-2000. The potential of CBAs, but not polyanions and other structural/functional classes of entry inhibitors, to impair

  19. Efficient mammalian germline transgenesis by cis-enhanced Sleeping Beauty transposition.

    Science.gov (United States)

    Carlson, Daniel F; Geurts, Aron M; Garbe, John R; Park, Chang-Won; Rangel-Filho, Artur; O'Grady, Scott M; Jacob, Howard J; Steer, Clifford J; Largaespada, David A; Fahrenkrug, Scott C

    2011-02-01

    Heightened interest in relevant models for human disease increases the need for improved methods for germline transgenesis. We describe a significant improvement in the creation of transgenic laboratory mice and rats by chemical modification of Sleeping Beauty transposons. Germline transgenesis in mice and rats was significantly enhanced by in vitro cytosine-phosphodiester-guanine methylation of transposons prior to injection. Heritability of transgene alleles was also greater from founder mice generated with methylated versus non-methylated transposon. The artificial methylation was reprogrammed in the early embryo, leading to founders that express the transgenes. We also noted differences in transgene insertion number and structure (single-insert versus concatemer) based on the influence of methylation and plasmid conformation (linear versus supercoiled), with supercoiled substrate resulting in efficient transpositional transgenesis (TnT) with near elimination of concatemer insertion. Combined, these substrate modifications resulted in increases in both the frequency of transgenic founders and the number of transgenes per founder, significantly elevating the number of potential transgenic lines. Given its simplicity, versatility and high efficiency, TnT with enhanced Sleeping Beauty components represents a compelling non-viral approach to modifying the mammalian germline.

  20. Heat stress is a potent stimulus for enhancing rescue efficiency of recombinant Borna disease virus.

    Science.gov (United States)

    Kojima, Shohei; Honda, Tomoyuki; Matsumoto, Yusuke; Tomonaga, Keizo

    2014-11-01

    Recently developed vector systems based on Borna disease virus (BDV) hold promise as platforms for efficient and stable gene delivery to the central nervous system (CNS). However, because it currently takes several weeks to rescue recombinant BDV (rBDV), an improved rescue procedure would enhance the utility of this system. Heat stress reportedly enhances the rescue efficiency of other recombinant viruses. Here, heat stress was demonstrated to increase the amount of BDV genome in persistently BDV-infected cells without obvious cytotoxicity. Further analyses suggested that the effect of heat stress on BDV infection is not caused by an increase in the activity of BDV polymerase. More cells in which BDV replication occurs were obtained in the initial phase of rBDV rescue by using heat stress than when it was not used. Thus, heat stress is a useful improvement on the published rescue procedure for rBDV. The present findings may accelerate the practical use of BDV vector systems in basic science and the clinic and thus enable broader adoption of this viral vector, which is uniquely suited for gene delivery to the CNS. © 2014 The Societies and Wiley Publishing Asia Pty Ltd.

  1. Efficient and Security Enhanced Anonymous Authentication with Key Agreement Scheme in Wireless Sensor Networks.

    Science.gov (United States)

    Jung, Jaewook; Moon, Jongho; Lee, Donghoon; Won, Dongho

    2017-03-21

    At present, users can utilize an authenticated key agreement protocol in a Wireless Sensor Network (WSN) to securely obtain desired information, and numerous studies have investigated authentication techniques to construct efficient, robust WSNs. Chang et al. recently presented an authenticated key agreement mechanism for WSNs and claimed that their authentication mechanism can both prevent various types of attacks, as well as preserve security properties. However, we have discovered that Chang et al's method possesses some security weaknesses. First, their mechanism cannot guarantee protection against a password guessing attack, user impersonation attack or session key compromise. Second, the mechanism results in a high load on the gateway node because the gateway node should always maintain the verifier tables. Third, there is no session key verification process in the authentication phase. To this end, we describe how the previously-stated weaknesses occur and propose a security-enhanced version for WSNs. We present a detailed analysis of the security and performance of our authenticated key agreement mechanism, which not only enhances security compared to that of related schemes, but also takes efficiency into consideration.

  2. Efficient and Security Enhanced Anonymous Authentication with Key Agreement Scheme in Wireless Sensor Networks

    Science.gov (United States)

    Jung, Jaewook; Moon, Jongho; Lee, Donghoon; Won, Dongho

    2017-01-01

    At present, users can utilize an authenticated key agreement protocol in a Wireless Sensor Network (WSN) to securely obtain desired information, and numerous studies have investigated authentication techniques to construct efficient, robust WSNs. Chang et al. recently presented an authenticated key agreement mechanism for WSNs and claimed that their authentication mechanism can both prevent various types of attacks, as well as preserve security properties. However, we have discovered that Chang et al’s method possesses some security weaknesses. First, their mechanism cannot guarantee protection against a password guessing attack, user impersonation attack or session key compromise. Second, the mechanism results in a high load on the gateway node because the gateway node should always maintain the verifier tables. Third, there is no session key verification process in the authentication phase. To this end, we describe how the previously-stated weaknesses occur and propose a security-enhanced version for WSNs. We present a detailed analysis of the security and performance of our authenticated key agreement mechanism, which not only enhances security compared to that of related schemes, but also takes efficiency into consideration. PMID:28335572

  3. Enhanced efficiency fertilisers: a review of formulation and nutrient release patterns.

    Science.gov (United States)

    Timilsena, Yakindra Prasad; Adhikari, Raju; Casey, Phil; Muster, Tim; Gill, Harsharn; Adhikari, Benu

    2015-04-01

    Fertilisers are one of the most important elements of modern agriculture. The application of fertilisers in agricultural practices has markedly increased the production of food, feed, fuel, fibre and other plant products. However, a significant portion of nutrients applied in the field is not taken up by plants and is lost through leaching, volatilisation, nitrification, or other means. Such a loss increases the cost of fertiliser and severely pollutes the environment. To alleviate these problems, enhanced efficiency fertilisers (EEFs) are produced and used in the form of controlled release fertilisers and nitrification/urease inhibitors. The application of biopolymers for coating in EEFs, tailoring the release pattern of nutrients to closely match the growth requirement of plants and development of realistic models to predict the release pattern of common nutrients have been the foci of fertiliser research. In this context, this paper intends to review relevant aspects of new developments in fertiliser production and use, agronomic, economic and environmental drives for enhanced efficiency fertilisers and their formulation process and the nutrient release behaviour. Application of biopolymers and complex coacervation technique for nutrient encapsulation is also explored as a promising technology to produce EEFs. © 2014 Society of Chemical Industry.

  4. Nitrogen fertilization enhances water-use efficiency in a saline environment.

    Science.gov (United States)

    Martin, Katherine C; Bruhn, Dan; Lovelock, Catherine E; Feller, Ilka C; Evans, John R; Ball, Marilyn C

    2010-03-01

    Effects of salinity and nutrients on carbon gain in relation to water use were studied in the grey mangrove, Avicennia marina, growing along a natural salinity gradient in south-eastern Australia. Tall trees characterized areas of seawater salinities (fringe zone) and stunted trees dominated landward hypersaline areas (scrub zone). Trees were fertilized with nitrogen (+N) or phosphorus (+P) or unfertilized. There was no significant effect of +P on shoot growth, whereas +N enhanced canopy development, particularly in scrub trees. Scrub trees maintained greater CO(2) assimilation per unit water transpired (water-use efficiency, WUE) and had lower nitrogen-use efficiency (NUE; CO(2) assimilation rate per unit leaf nitrogen) than fringe trees. The CO(2) assimilation rates of +N trees were similar to those in other treatments, but were achieved at lower transpiration rates, stomatal conductance and intercellular CO(2) concentrations. Maintaining comparable assimilation rates at lower stomatal conductance requires greater ribulose 1.5-bisphosphate carboxylase/oxygenase activity, consistent with greater N content per unit leaf area in +N trees. Hence, +N enhanced WUE at the expense of NUE. Instantaneous WUE estimates were supported by less negative foliar delta(13)C values for +N trees and scrub control trees. Thus, nutrient enrichment may alter the structure and function of mangrove forests along salinity gradients.

  5. Enhanced Locomotion Efficiency of a Bio-inspired Walking Robot using Contact Surfaces with Frictional Anisotropy

    Science.gov (United States)

    Manoonpong, Poramate; Petersen, Dennis; Kovalev, Alexander; Wörgötter, Florentin; Gorb, Stanislav N.; Spinner, Marlene; Heepe, Lars

    2016-12-01

    Based on the principles of morphological computation, we propose a novel approach that exploits the interaction between a passive anisotropic scale-like material (e.g., shark skin) and a non-smooth substrate to enhance locomotion efficiency of a robot walking on inclines. Real robot experiments show that passive tribologically-enhanced surfaces of the robot belly or foot allow the robot to grip on specific surfaces and move effectively with reduced energy consumption. Supplementing the robot experiments, we investigated tribological properties of the shark skin as well as its mechanical stability. It shows high frictional anisotropy due to an array of sloped denticles. The orientation of the denticles to the underlying collagenous material also strongly influences their mechanical interlocking with the substrate. This study not only opens up a new way of achieving energy-efficient legged robot locomotion but also provides a better understanding of the functionalities and mechanical properties of anisotropic surfaces. That understanding will assist developing new types of material for other real-world applications.

  6. Feasible, Efficient and Necessary, without Exception - Working with Sex Workers Interrupts HIV/STI Transmission and Brings Treatment to Many in Need.

    Science.gov (United States)

    Steen, Richard; Wheeler, Tisha; Gorgens, Marelize; Mziray, Elizabeth; Dallabetta, Gina

    2015-01-01

    High rates of partner change in sex work-whether in professional, 'transactional' or other context-disproportionately drive transmission of HIV and other sexually transmitted infections. Several countries in Asia have demonstrated that reducing transmission in sex work can reverse established epidemics among sex workers, their clients and the general population. Experience and emerging research from Africa reaffirms unprotected sex work to be a key driver of sexual transmission in different contexts and regardless of stage or classification of HIV epidemic. This validation of the epidemiology behind sexual transmission carries an urgent imperative to realign prevention resources and scale up effective targeted interventions in sex work settings, and, given declining HIV resources, to do so efficiently. Eighteen articles in this issue highlight the importance and feasibility of such interventions under four themes: 1) epidemiology, data needs and modelling of sex work in generalised epidemics; 2) implementation science addressing practical aspects of intervention scale-up; 3) community mobilisation and 4) the treatment cascade for sex workers living with HIV. Decades of empirical evidence, extended by analyses in this collection, argue that protecting sex work is, without exception, feasible and necessary for controlling HIV/STI epidemics. In addition, the disproportionate burden of HIV borne by sex workers calls for facilitated access to ART, care and support. The imperative for Africa is rapid scale-up of targeted prevention and treatment, facilitated by policies and action to improve conditions where sex work takes place. The opportunity is a wealth of accumulated experience working with sex workers in diverse settings, which can be tapped to make up for lost time. Elsewhere, even in countries with strong interventions and services for sex workers, an emerging challenge is to find ways to sustain them in the face of declining global resources.

  7. Efficiency of an enhanced linear optical Bell-state measurement scheme with realistic imperfections

    Science.gov (United States)

    Wein, Stephen; Heshami, Khabat; Fuchs, Christopher A.; Krovi, Hari; Dutton, Zachary; Tittel, Wolfgang; Simon, Christoph

    2016-09-01

    We compare the standard 50%-efficient single beam splitter method for Bell-state measurement to a proposed 75%-efficient auxiliary-photon-enhanced scheme [W. P. Grice, Phys. Rev. A 84, 042331 (2011), 10.1103/PhysRevA.84.042331] in light of realistic conditions. The two schemes are compared with consideration for high input state photon loss, auxiliary state photon loss, detector inefficiency and coupling loss, detector dark counts, and non-number-resolving detectors. We also analyze the two schemes when multiplexed arrays of non-number-resolving detectors are used. Furthermore, we explore the possibility of utilizing spontaneous parametric down-conversion as the auxiliary photon pair source required by the enhanced scheme. In these different cases, we determine the bounds on the detector parameters at which the enhanced scheme becomes superior to the standard scheme and describe the impact of the different imperfections on measurement success rate and discrimination fidelity. This is done using a combination of numeric and analytic techniques. For many of the cases discussed, the size of the Hilbert space and the number of measurement outcomes can be very large, which makes direct numerical solutions computationally costly. To alleviate this problem, all of our numerical computations are performed using pure states. This requires tracking the loss modes until measurement and treating dark counts as variations on measurement outcomes rather than modifications to the state itself. In addition, we provide approximate analytic expressions that illustrate the effect of different imperfections on the Bell-state analyzer quality.

  8. Mesoporous SnO2-coated metal nanoparticles with enhanced catalytic efficiency.

    Science.gov (United States)

    Zhou, Na; Polavarapu, Lakshminarayana; Wang, Qing; Xu, Qing-Hua

    2015-03-04

    Aggregation of plasmonic nanoparticles under harsh conditions has been one of the major obstacles to their potential applications. Here we present the preparation of uniform mesoporous SnO2 shell coated Au nanospheres, Au nanorods and Au/Ag core-shell nanorods and their applications in molecular sensing and catalysis. In these nanostructures, the mesoporous SnO2 shell stabilizes the metal nanoparticle and allows the metal core to be exposed to the surrounding environment for various applications at the same time. These nanostructures display high refractive index sensitivity, which makes them promising materials for LSPR based molecular sensing. Applications of these materials as catalysts for reduction of 4-nitrophenol by NaBH4 have also been demonstrated. Both uncoated and SnO2-coated anisotropic Au and Au/Ag nanorods were found to display significantly better catalytic efficiency compared to the corresponding spherical Au nanoparticles. Catalytic activities of different metal nanoparticles were significantly enhanced by 4-6 times upon coating with the mesoporous SnO2 shell. The enhanced catalytic activity of metal nanoparticles upon SnO2 coating was attributed to charge-redistribution between noble metal and SnO2 that disperses the electrons to a large area and prolonged electron lifetime in SnO2-coated metal nanoparticles. The charge transfer mechanism of enhanced catalytic efficiency for SnO2-coated metal nanoparticles has been further demonstrated by photochemical reduction of silver ions on the outer surface of these NPs. These metal/semiconductor core-shell nanomaterials are potentially useful for various applications such as molecular sensing and catalysis.

  9. Enhanced metabolic efficiency contributes to weight regain after weight loss in obesity-prone rats.

    Science.gov (United States)

    MacLean, Paul S; Higgins, Janine A; Johnson, Ginger C; Fleming-Elder, Brooke K; Donahoo, William T; Melanson, Edward L; Hill, James O

    2004-12-01

    Metabolic adjustments occur with weight loss that may contribute to a high rate of weight regain. We have previously observed in obesity-prone, obese rats that weight reduction is accompanied by a suppression in resting metabolic rate beyond what would be predicted for the change in metabolic mass. In the present study, we examine if this adjustment in metabolic efficiency is affected by the length of time in weight maintenance and if it contributes to the propensity to regain after weight loss. Twenty-four-hour, nonresting, and resting energy expenditure (REE) were obtained by indirect calorimetry and normalized to metabolic mass estimated by dual-energy X-ray absorptiometry. A 10% loss in body weight in weight-reduced rats was accompanied by a 15% suppression in adjusted REE. This enhancement in metabolic efficiency was not altered with either 8 or 16 wk of weight maintenance, but it did resolve when the forced control of intake was removed and the weight was regained. The rate of weight regain increased with the time in weight maintenance and was exceptionally high early during the relapse period. During this high rate of weight gain, the suppression in REE persists while consumption increases to a level that is higher than when they were obese. In summary, an enhanced metabolic efficiency and an elevated appetite both contribute (60% and 40%, respectively) to a large potential energy imbalance that, when the forcible control of energy intake is relieved, becomes actualized and results in an exceptionally high rate of weight regain.

  10. Families as catalysts for peer adherence support in enhancing hope for people living with HIV/AIDS in South Africa.

    Science.gov (United States)

    Masquillier, Caroline; Wouters, Edwin; Mortelmans, Dimitri; Booysen, Frederik le Roux

    2014-01-01

    Hope is an essential dimension of successful coping in the context of illnesses such as HIV/AIDS, because positive expectations for the future alleviate emotional distress, enhance quality of life and have been linked to the capacity for behavioural change. The social environment (e.g. family, peers) is a regulator of hope for people living with HIV/AIDS (PLWHA). In this regard, the dual aim of this article is (1) to analyze the influence of a peer adherence support (PAS) intervention and the family environment on the state of hope in PLWHA and (2) to investigate the interrelationship between the two determinants. The Effective AIDS Treatment and Support in the Free State study is a prospective randomized controlled trial. Participants were recruited from 12 public antiretroviral treatment (ART) clinics across five districts in the Free State Province of South Africa. Each of these patients was assigned to one of the following groups: a control group receiving standard care, a group receiving additional biweekly PAS or a group receiving PAS and nutritional support. Latent cross-lagged modelling (Mplus) was used to analyse the impact of PAS and the family environment on the level of hope in PLWHA. The results of the study indicate that neither PAS nor the family environment has a direct effect on the level of hope in PLWHA. Subsequent analysis reveals a positive significant interaction between family functioning and PAS at the second follow-up, indicating that better family functioning increases the positive effect of PAS on the state of hope in PLWHA. The interplay between well-functioning families and external PAS generates higher levels of hope, which is an essential dimension in the success of lifelong treatment. This study provides additional insight into the important role played by family dynamics in HIV/AIDS care, and it underscores the need for PAS interventions that are sensitive to the contexts in which they are implemented.

  11. Families as catalysts for peer adherence support in enhancing hope for people living with HIV/AIDS in South Africa

    Directory of Open Access Journals (Sweden)

    Caroline Masquillier

    2014-04-01

    Full Text Available Introduction: Hope is an essential dimension of successful coping in the context of illnesses such as HIV/AIDS, because positive expectations for the future alleviate emotional distress, enhance quality of life and have been linked to the capacity for behavioural change. The social environment (e.g. family, peers is a regulator of hope for people living with HIV/AIDS (PLWHA. In this regard, the dual aim of this article is (1 to analyze the influence of a peer adherence support (PAS intervention and the family environment on the state of hope in PLWHA and (2 to investigate the interrelationship between the two determinants. Methods: The Effective AIDS Treatment and Support in the Free State study is a prospective randomized controlled trial. Participants were recruited from 12 public antiretroviral treatment (ART clinics across five districts in the Free State Province of South Africa. Each of these patients was assigned to one of the following groups: a control group receiving standard care, a group receiving additional biweekly PAS or a group receiving PAS and nutritional support. Latent cross-lagged modelling (Mplus was used to analyse the impact of PAS and the family environment on the level of hope in PLWHA. Results: The results of the study indicate that neither PAS nor the family environment has a direct effect on the level of hope in PLWHA. Subsequent analysis reveals a positive significant interaction between family functioning and PAS at the second follow-up, indicating that better family functioning increases the positive effect of PAS on the state of hope in PLWHA. Conclusions: The interplay between well-functioning families and external PAS generates higher levels of hope, which is an essential dimension in the success of lifelong treatment. This study provides additional insight into the important role played by family dynamics in HIV/AIDS care, and it underscores the need for PAS interventions that are sensitive to the contexts in

  12. Enhanced Th17 phenotype in uninfected neonates born from viremic HIV-1-infected pregnant women.

    Science.gov (United States)

    Hygino, Joana; Vieira, Morgana M; Guillermo, Landi V; Silva-Filho, Renato G; Saramago, Carmen; Lima-Silva, Agostinho A; Andrade, Regis M; Andrade, Arnaldao F B; Brindeiro, Rodrigo M; Tanuri, Amilcar; Guimarães, Vander; de Melo Bento, Cleonice Alves

    2011-04-01

    Our objective was to evaluate the in vitro functional profile of T cells from uninfected neonates born from HIV-1-infected pregnant women who controlled (G1) or not (G2) the virus replication. We demonstrated that the lymphoproliferation of T cell to polyclonal activators was higher in the G2 as compared with G1. Nevertheless, no detectable proliferative response was observed in response to HIV-1 antigens in both neonate groups. Cytokine dosage in the supernatants of these polyclonally activated T cell cultures demonstrated that, while IL-10 was the dominant cytokine produced in G1, Th17-related cytokines were significantly higher in G2 neonates. The higher Th17 phenotype tendency in G2 was related to high production of IL-23 by lipopolysaccharide-activated monocyte-derived dendritic cells from these neonates. Our results demonstrated immunological disorders in uninfected neonates born from viremic HIV-1-infected mothers that can help to explain why some of these children have elevated risk of clinical morbidity and mortality due to pathological hypersensitivity.

  13. Observation of Significant Quantum Efficiency Enhancement from a Polarized Photocathode with Distributed Bragg Reflector

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shukui [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Poelker, Matthew [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Stutzman, Marcy L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Chen, Yiqiao [SVT Associates, Inc., Eden Prairie, MN (United States); Moy, Aaron [SVT Associates, Inc., Eden Prairie, MN (United States)

    2015-09-01

    Polarized photocathodes with higher Quantum efficiency (QE) would help to reduce the technological challenge associated with producing polarized beams at milliampere levels, because less laser light would be required, which simplifies photocathode cooling requirements. And for a given amount of available laser power, higher QE would extend the photogun operating lifetime. The distributed Bragg reflector (DBR) concept was proposed to enhance the QE of strained-superlattice photocathodes by increasing the absorption of the incident photons using a Fabry-Perot cavity formed between the front surface of the photocathode and the substrate that includes a DBR, without compromising electron polarization. Here we present recent results showing QE enhancement of a GaAs/GaAsP strained-superlattice photocathode made with a DBR structure. Typically, a GaAs/GaAsP strained-superlattice photocathode without DBR provides a QE of 1%, at a laser wavelength corresponding to peak polarization. In comparison, the GaAs/GaAsP strained-superlattice photocathodes with DBR exhibited an enhancement of over 2 when the incident laser wavelength was tuned to meet the resonant condition for the Fabry-Perot resonator.

  14. Protonation process of conjugated polyelectrolytes on enhanced power conversion efficiency in the inverted polymer solar cells

    Science.gov (United States)

    Yi, Chao; Hu, Rong; Ren, He; Hu, Xiaowen; Wang, Shu; Gong, Xiong; Cao, Yong

    2014-01-01

    In this study, two conjugated polyelectrolytes, polythiophene derivative (PTP) and poly[(9,9-bis [6‧-N, N, N-trimethylammonium] hexyl)-fluorenylene-phenylene] dibromide (PFP), are utilized to modify the surface properties of ZnO electron extraction layer (EEL) in the inverted polymer solar cells (PSCs). Both higher short-circuit current densities and larger open-circuit voltages were observed from the inverted PSCs with ZnO/PFP or ZnO/PTP as compared with those only with ZnO EEL. The protonation process for PTP and PFP in solution is distinguished. Overall, more than 40% enhanced power conversion efficiency (PCE) from the inverted PSCs with ZnO/PFP, in which the PFP could be fully ionized in deionized water, and more than 30% enhanced PCE from the inverted PSCs with ZnO/PTP, as the case that the PTP could not be fully ionized in deionized water, as compared with the inverted PSCs with ZnO EEL were observed, respectively. These results demonstrate that the conjugated polyelectrolytes play an important role in enhancement of device performance of inverted PSCs and that the protonation process of the conjugated polyelectrolytes is critical to the modification for EEL in PSCs.

  15. Overcoming Intrinsic Restriction Enzyme Barriers Enhances Transformation Efficiency in Arthrospira platensis C1.

    Science.gov (United States)

    Jeamton, Wattana; Dulsawat, Sudarat; Tanticharoen, Morakot; Vonshak, Avigad; Cheevadhanarak, Supapon

    2017-04-01

    The development of a reliable genetic transformation system for Arthrospira platensis has been a long-term goal, mainly for those trying either to improve its performance in large-scale cultivation systems or to enhance its value as food and feed additives. However, so far, most of the attempts to develop such a transformation system have had limited success. In this study, an efficient and stable transformation system for A. platensis C1 was successfully developed. Based on electroporation and transposon techniques, exogenous DNA could be transferred to and stably maintained in the A. platensis C1 genome. Most strains of Arthrospira possess strong restriction barriers, hampering the development of a gene transfer system for this group of cyanobacteria. By using a type I restriction inhibitor and liposomes to protect the DNA from nuclease digestion, the transformation efficiency was significantly improved. The transformants were able to grow on a selective medium for more than eight passages, and the transformed DNA could be detected from the stable transformants. We propose that the intrinsic endonuclease enzymes, particularly the type I restriction enzyme, in A. platensis C1 play an important role in the transformation efficiency of this industrial important cyanobacterium. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  16. Novel Efficient Cell-Penetrating, Peptide-Mediated Strategy for Enhancing Telomerase Inhibitor Oligonucleotides.

    Science.gov (United States)

    Muñoz-Alarcón, Andrés; Eriksson, Jonas; Langel, Ülo

    2015-12-01

    At present, there are several therapeutic approaches for targeting telomerase in tumors. One in particular, currently undergoing clinical trials, is based on synthetic lipid-modified oligonucleotide antagonists aimed at inhibiting the ribonucleoprotein subunit of human telomerase. However, while enabling efficient uptake, the lipid modifications reduce the potency of the therapeutic oligonucleotides compared to nonmodified oligonucleotides. Moreover, lipid modification may increase oligonucleotide accumulation in the liver causing undesirable hepatotoxicity. Noncovalent complexation strategies for cell-penetrating peptide (CPP)-mediated delivery present an option to circumvent the need for potency-reducing modifications, while allowing for a highly efficient uptake, and could significantly improve the efficiency of telomerase-targeting cancer therapeutics. Delivery of a nonlipidated locked nucleic acid/2'-O-methyl mixmer significantly inhibits the telomerase activity in treated HeLa cells. The inhibitory effect was further improved through addition of a CPP. Furthermore, calculated IC50-values for the oligonucleotide delivered by CPPs into HeLa cells are more than 20 times lower than telomerase inhibitor Imetelstat, currently undergoing clinical trials. These results emphasize the potential of CPP-mediated delivery of future pharmaceuticals and provide means by which to enhance an already promising therapeutic strategy for cancer treatment.

  17. High-Efficiency, High-Capacity, Low-NOx Aluminum Melting Using Oxygen-Enhanced Combustion

    Energy Technology Data Exchange (ETDEWEB)

    D' Agostini, M.D.

    2000-06-02

    This report describes the development and application of a novel oxygen enhanced combustion system with an integrated vacuum swing adsorption (VSA) oxygen supply providing efficient, low NOx melting in secondary aluminum furnaces. The mainstay of the combustion system is a novel air-oxy-natural gas burner that achieves high productivity and energy efficiency with low NOx emissions through advanced mixing concepts and the use of separate high- and low-purity oxidizer streams. The technology was installed on a reverberatory, secondary aluminum melting plant at the Wabash Aluminum Alloy's Syracuse, N.Y. plant, where it is currently in operation. Field testing gave evidence that the new burner technology meets the stringent NOx emissions target of 0.323 lb NO2/ton aluminum, thus complying with regulations promulgated by Southern California's South Coast Air Quality Management District (SCAQMD). Test results also indicated that the burner technology exceeded fuel efficiency and melting capacity goals. Economic modeling showed that the novel air-oxy-fuel (ADF) combustion technology provides a substantial increase in furnace profitability relative to air-fuel operation. Model results also suggest favorable economics for the air-oxy-fuel technology relative to a full oxy-fuel conversion of the furnace.

  18. Hybrid silicon honeycomb/organic solar cells with enhanced efficiency using surface etching

    Science.gov (United States)

    Liu, Ruiyuan; Sun, Teng; Liu, Jiawei; Wu, Shan; Sun, Baoquan

    2016-06-01

    Silicon (Si) nanostructure-based photovoltaic devices are attractive for their excellent optical and electrical performance, but show lower efficiency than their planar counterparts due to the increased surface recombination associated with the high surface area and roughness. Here, we demonstrate an efficiency enhancement for hybrid nanostructured Si/polymer solar cells based on a novel Si honeycomb (SiHC) structure using a simple etching method. SiHC structures are fabricated using a combination of nanosphere lithography and plasma treatment followed by a wet chemical post-etching. SiHC has shown superior light-trapping ability in comparison with the other Si nanostructures, along with a robust structure. Anisotropic tetramethylammonium hydroxide etching not only tunes the final surface morphologies of the nanostructures, but also reduces the surface roughness leading to a lower recombination rate in the hybrid solar cells. The suppressed recombination loss, benefiting from the reduced surface-to-volume ratio and roughness, has resulted in a high open-circuit voltage of 600 mV, a short-circuit current of 31.46 mA cm-2 due to the light-trapping ability of the SiHCs, and yields a power conversion efficiency of 12.79% without any other device structure optimization.

  19. Heterogeneous photocatalysis for air and water treatment: Fundamental needs for quantum efficiency enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Ollis, D.F. [North Carolina State Univ., Raleigh, NC (United States)

    1996-09-01

    In the remediation industries, a useful treatment technology must be {open_quotes}general, robust, and cheap{close_quotes}. Among oxidation processes, heterogeneous photocatalysis is now broadly demonstrated to destroy common water and air contaminants. The potential process uses of highly stable titania, long lived lamps (one year), and room temperature operation, indicating a simple and robust process. We are left to address the third criterion: Can photocatalysis be {open_quotes}cheap{close_quotes}? In both liquid phase and gas phase treatment and purification by photocatalysis, it is established that the primary barrier to commercialization is often cost. Cost in return is dominated by the efficiency with which solar or lamp photons are harvested for productive light, and subsequent dark, reactions. This paper therefore defines fundamental needs in photocatalysis for pollution control in terms of activities which could lead to quantum efficiency enhancement. We first recall three related definitions. The quantum yield (QY) is the ratio of molecules of reactant converted per photon absorbed, a fundamental quantity. A less fundamental, but more easily measured variable is the quantum efficiency (QE), the ratio of molecules converted per photon entering the reactor. A third variable is the energy required per order of magnitude pollutant reduction, or EEO, a definition which provides for easy energy cost comparisons among different technologies. Each measure cited here reflects the photon, and thus the electrical, cost of this photochemistry.

  20. Enhancement of optics-to-THz conversion efficiency by metallic slot waveguides.

    Science.gov (United States)

    Ruan, Zhichao; Veronis, Georgios; Vodopyanov, Konstantin L; Fejer, Marty M; Fan, Shanhui

    2009-08-03

    A metallic slot waveguide, with a dielectric strip embedded within, is investigated for the purpose of enhancing the optics-to-THz conversion efficiency using the difference-frequency generation (DFG) process. To describe the frequency conversion process in such lossy waveguides, a fully-vectorial coupled-mode theory is developed. Using the coupled-mode theory, we outline the basic theoretical requirements for efficient frequency conversion, which include the needs to achieve large coupling coefficients, phase matching, and low propagation loss for both the optical and THz waves. Following these requirements, a metallic waveguide is designed by considering the trade-off between modal confinement and propagation loss. Our numerical calculation shows that the conversion efficiency in these waveguide structures can be more than one order of magnitude larger than what has been achieved using dielectric waveguides. Based on the distinct impact of the slot width on the optical and THz modal dispersion, we propose a two-step method to realize the phase matching for general pump wavelengths.

  1. Bifacial dye-sensitized solar cells with enhanced rear efficiency and power output.

    Science.gov (United States)

    Cai, Hongyuan; Tang, Qunwei; He, Benlin; Li, Ru; Yu, Liangmin

    2014-12-21

    Pursuing a high power conversion efficiency with no sacrifice of cost-effectiveness has been a persistent objective for dye-sensitized solar cells (DSSCs). One promising solution to this impasse is increased light harvesting. Previous efforts in light harvesting have been made on setting blocking layers or reflecting layers, or adding a light harvester, resulting in tedious procedures without reducing the expenses. We present a mild solution strategy for synthesizing transparent Ru-Se alloy counter electrodes (CEs) for bifacial DSSC applications, displaying optimal front and rear efficiencies of 8.76% and 5.90%, respectively. In comparison with pristine Pt-based solar cells, the maximum power output has also been markedly enhanced. Moreover, fast start-up, high multiple start capability, and good stability are observed in the bifacial DSSCs with transparent Ru-Se binary alloy electrodes. The impressive efficiencies along with simple preparation of the cost-effective Ru-Se alloy CEs demonstrates their potential application in robust DSSCs.

  2. αEnv-decorated phosphatidylserine liposomes trigger phagocytosis of HIV-virus-like particles in macrophages.

    Science.gov (United States)

    Gramatica, Andrea; Petazzi, Roberto A; Lehmann, Maik J; Ziomkowska, Joanna; Herrmann, Andreas; Chiantia, Salvatore

    2014-07-01

    Macrophages represent an important cellular target of HIV-1. Interestingly, they are also believed to play a potential role counteracting its infection. However, HIV-1 is known to impair macrophage immune functions such as antibody-mediated phagocytosis. Here, we present immunoliposomes that can bind HIV-1 virus-like particles (HIV-VLPs) while being specifically phagocytosed by macrophages, thus allowing the co-internalization of HIV-VLPs. These liposomes are decorated with anti-Env antibodies and contain phosphatidylserine (PS). PS mediates liposome internalization by macrophages via a mechanism not affected by HIV-1. Hence, PS-liposomes mimic apoptotic cells and are internalized into the macrophages due to specific recognition, carrying the previously bound HIV-VLPs. With a combination of flow cytometry, confocal live-cell imaging and electron microscopy we demonstrate that the PS-immunoliposomes presented here are able to elicit efficient HIV-VLPs phagocytosis by macrophages and might represent a new nanotechnological approach to enhance HIV-1 antigen presentation and reduce the ongoing inflammation processes. This team of authors demonstrate that specific phosphatidylserin immunoliposomes are able to elicit efficient phagocytosis of HIV-virus-like particle by macrophages and might represent a new nanomedicine approach to enhance HIV-1 antigen presentation and reduce ongoing inflammation processes. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Enhanced emission efficiency in organic light-emitting diodes using deoxyribonucleic acid complex as an electron blocking layer

    Science.gov (United States)

    Hagen, J. A.; Li, W.; Steckl, A. J.; Grote, J. G.

    2006-04-01

    Enhanced electroluminescent efficiency using a deoxyribonucleic acid (DNA) complex as an electron blocking (EB) material has been demonstrated in both green- and blue-emitting organic light-emitting diodes (OLEDs). The resulting so-called BioLEDs showed a maximum luminous efficiency of 8.2 and 0.8cd/A, respectively. The DNA-based BioLEDs were as much as 10× more efficient and 30× brighter than their OLED counterparts.

  4. Does integration of HIV and sexual and reproductive health services improve technical efficiency in Kenya and Swaziland? An application of a two-stage semi parametric approach incorporating quality measures

    Science.gov (United States)

    Obure, Carol Dayo; Jacobs, Rowena; Guinness, Lorna; Mayhew, Susannah; Vassall, Anna

    2016-01-01

    Theoretically, integration of vertically organized services is seen as an important approach to improving the efficiency of health service delivery. However, there is a dearth of evidence on the effect of integration on the technical efficiency of health service delivery. Furthermore, where technical efficiency has been assessed, there have been few attempts to incorporate quality measures within efficiency measurement models particularly in sub-Saharan African settings. This paper investigates the technical efficiency and the determinants of technical efficiency of integrated HIV and sexual and reproductive health (SRH) services using data collected from 40 health facilities in Kenya and Swaziland for 2008/2009 and 2010/2011. Incorporating a measure of quality, we estimate the technical efficiency of health facilities and explore the effect of integration and other environmental factors on technical efficiency using a two-stage semi-parametric double bootstrap approach. The empirical results reveal a high degree of inefficiency in the health facilities studied. The mean bias corrected technical efficiency scores taking quality into consideration varied between 22% and 65% depending on the data envelopment analysis (DEA) model specification. The number of additional HIV services in the maternal and child health unit, public ownership and facility type, have a positive and significant effect on technical efficiency. However, number of additional HIV and STI services provided in the same clinical room, proportion of clinical staff to overall staff, proportion of HIV services provided, and rural location had a negative and significant effect on technical efficiency. The low estimates of technical efficiency and mixed effects of the measures of integration on efficiency challenge the notion that integration of HIV and SRH services may substantially improve the technical efficiency of health facilities. The analysis of quality and efficiency as separate dimensions of

  5. Enhancing the health of women living with HIV: the SMART/EST Women's Project

    Directory of Open Access Journals (Sweden)

    Stephen M Weiss

    2011-02-01

    Full Text Available Stephen M Weiss1, Jonathan N Tobin2, Michael Antoni1, Gail Ironson1, Mary Ishii1, Anita Vaughn2, Andrea Cassells2, Deborah Jones1, Neil Schneiderman1, Elizabeth Brondolo3, Arthur LaPerriere1, Maria Lopez1, Olga Villar-Loubet1, Joanne Camille2, Mahendra Kumar1, J Bryan Page1, SMART/EST Women's Project Team*1University of Miami, Miami, FL, USA; 2Clinical Directors Network, New York, NY, USA; 3St Johns University, Queens, NY, USA; *The SMART/EST Womens' Project Team: DeVieux J, Jean-Gilles M, Gousse Y, Alexander K, Bustamonte V, Lopez E, Casani J, Stanley H, Asthana D, Van Splunteren F, Goldstein A, Nasajon R, Wiesner Y, Zukerman M, Segal-Isaacson CJ, Romanowsky A, Masheb R, Coma C, Ubiera M, D'Andrea SM, Ittai N.Abstract: The principal objective of these multisite studies (Florida, New York, New Jersey: epicenters for human immunodeficiency virus [HIV] among women was to develop and implement effective combinations of behavioral interventions to optimize the health status of the most neglected and understudied population affected by the acquired immunodeficiency syndrome (AIDS epidemic in the United States: poor women of color living with HIV. The two studies enrolled nearly 900 women randomly assigned to “high intensity” (cognitive–behavioral stress management training combined with expressive–supportive therapy [CBSM]+ group or “low intensity” (individual psychoeducational program treatment conditions over a period of 9 years. The initial study of the stress management and relaxation training/expressive–supportive therapy (SMART/EST Women's Project (SWP I focused on reducing depression and anxiety, as well as improving self-efficacy and overall quality of life for women with case-defined AIDS. Findings from this study demonstrated the utility of CBSM+ in reducing distress (depression, anxiety and denial, while improving social support, self-efficacy, coping skills, and quality of life. The second study (SWP II, which included all

  6. Enhanced Locomotion Efficiency of a Bio-inspired Walking Robot using Contact Surfaces with Frictional Anisotropy

    DEFF Research Database (Denmark)

    Manoonpong, Poramate; Petersen, Dennis; Kovalev, Alexander

    2016-01-01

    show that passive tribologically-enhanced surfaces of the robot belly or foot allow the robot to grip on specific surfaces and move effectively with reduced energy consumption. Supplementing the robot experiments, we investigated tribological properties of the shark skin as well as its mechanical...... stability. It shows high frictional anisotropy due to an array of sloped denticles. The orientation of the denticles to the underlying collagenous material also strongly influences their mechanical interlocking with the substrate. This study not only opens up a new way of achieving energy-efficient legged...... robot locomotion but also provides a better understanding of the functionalities and mechanical properties of anisotropic surfaces. That understanding will assist developing new types of material for other real-world applications....

  7. Printable luminescent down shifter for enhancing efficiency and stability of organic photovoltaics

    DEFF Research Database (Denmark)

    Kettle, J.; Bristow, N.; Gethin, D.T.

    2016-01-01

    , with a 51% enhancement in the measured stability (T75%). Significantly, the work provides clear experimental evidence that the LDS layer can act as a UV filter in OPVs without compromising the efficiency of the solar cell, thus providing an added benefit over commercial UV filters.......The proof of concept of using luminescent down shifting (LDS) layers as alternative UV filters for P3HT:PCBM OPVs is demonstrated using a lanthanide-based metal complex. The results are verified using a combination of indoor light soaking, with single cell devices, and outdoor performance...... half-life (T50%). The OPV modules were encapsulated and tested for outdoor stability over a 70 day period in the Negev desert, Israel. The modules made with the LDS filter are shown to match the stability of those made with a commercial UV filter and outperform the modules with no filter applied...

  8. Regulating the spatial distribution of metal nanoparticles within metal-organic frameworks to enhance catalytic efficiency

    Science.gov (United States)

    Yang, Qiu; Liu, Wenxian; Wang, Bingqing; Zhang, Weina; Zeng, Xiaoqiao; Zhang, Cong; Qin, Yongji; Sun, Xiaoming; Wu, Tianpin; Liu, Junfeng; Huo, Fengwei; Lu, Jun

    2017-01-01

    Composites incorporating metal nanoparticles (MNPs) within metal-organic frameworks (MOFs) have broad applications in many fields. However, the controlled spatial distribution of the MNPs within MOFs remains a challenge for addressing key issues in catalysis, for example, the efficiency of catalysts due to the limitation of molecular diffusion within MOF channels. Here we report a facile strategy that enables MNPs to be encapsulated into MOFs with controllable spatial localization by using metal oxide both as support to load MNPs and as a sacrificial template to grow MOFs. This strategy is versatile to a variety of MNPs and MOF crystals. By localizing the encapsulated MNPs closer to the surface of MOFs, the resultant MNPs@MOF composites not only exhibit effective selectivity derived from MOF cavities, but also enhanced catalytic activity due to the spatial regulation of MNPs as close as possible to the MOF surface. PMID:28195131

  9. Michrohole Arrays Drilled with Advanced Abrasive Slurry Jet Technology to Efficiently Exploit Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Oglesby, Kenneth [Impact Technologies, Tulsa, OK (United States); Finsterle, Stefan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhang, Yingqi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Pan, Lehua [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dobson, Parick [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mohan, Ram [Univ. of Tulsa, OK (United States); Shoham, Ovadia [Univ. of Tulsa, OK (United States); Felber, Betty [Impact Technologies, Tulsa, OK (United States); Rychel, Dwight [Impact Technologies, Tulsa, OK (United States)

    2014-03-12

    This project had two major areas of research for Engineered/ Enhanced Geothermal System (EGS) development - 1) study the potential benefits from using microholes (i.e., bores with diameters less than 10.16 centimeters/ 4 inches) and 2) study FLASH ASJ to drill/ install those microbores between a well and a fracture system. This included the methods and benefits of drilling vertical microholes for exploring the EGS reservoir and for installing multiple (forming an array of) laterals/ directional microholes for creating the in-reservoir heat exchange flow paths. Significant benefit was found in utilizing small microbore sized connecting bores for EGS efficiency and project life. FLASH ASJ was deemed too complicated to optimally work in such deep reservoirs at this time.

  10. Triphenyl Phosphine-Functionalized Chitosan Nanoparticles Enhanced Antitumor Efficiency Through Targeted Delivery of Doxorubicin to Mitochondria

    Science.gov (United States)

    Hou, Jiahui; Yu, Xiwei; Shen, Yaping; Shi, Yijie; Su, Chang; Zhao, Liang

    2017-02-01

    Mitochondria as an important organ in eukaryotic cells produced energy through oxidative phosphorylation and also played an important role in regulating the apoptotic signal transduction process. Importantly, mitochondria like nuclei also contained the functional DNA and were very sensitive to anticancer drugs which could effectively inhibit the synthesis of nucleic acid, especially the production of DNA. In this work, we designed novel triphenyl phosphine (TPP)-conjugated chitosan (CS) nanoparticles (NPs) for efficient drug delivery to cell mitochondria. The results showed that compared with free doxorubicin (Dox), Dox-loaded TPP-NPs were specifically distributed in mitochondria of tumor cells and interfered with the function of mitochondria, thus resulted in the higher cytotoxicity and induced the significant cell apoptosis effect. Taken together, triphenyl phosphine-conjugated chitosan nanoparticles may become a promising mitochondria-targeting nanocarrier candidate for enhancing antitumor effects.

  11. Enhancement of HIV-1 DNA vaccine immunogenicity by BCG-PSN, a novel adjuvant.

    Science.gov (United States)

    Sun, Jing; Hou, Jue; Li, Dingfeng; Liu, Yong; Hu, Ningzhu; Hao, Yanling; Fu, Jingjing; Hu, Yunzhang; Shao, Yiming

    2013-01-07

    Although the importance of DNA vaccines, especially as a priming immunization has been well established in numerous HIV vaccine studies, the immunogenictiy of DNA vaccines is generally moderate. Novel adjuvant is in urgent need for improving the immunogenicity of DNA vaccine. Polysaccharide and nucleic acid fraction extracted by hot phenol method from Mycobacterium bovis bacillus Calmette-Guérin, known as BCG-PSN, is a widely used immunomodulatory product in China clinical practice. In this study, we evaluated whether the BCG-PSN could serve as a novel adjuvant of DNA vaccine to trigger better cellular and humoral immune responses against the HIV-1 Env antigen in Balb/C mouse model. The BCG-PSN was mixed with 10 μg or 100 μg of pDRVI1.0gp145 (HIV-1 CN54 gp145 gene) DNA vaccine and intramuscularly immunized two or three times. We found that BCG-PSN could significantly improve the immunogenicity of DNA vaccine when co-administered with DNA vaccine. Further, at the same vaccination schedule, BCG-PSN co-immunization with 10 μg DNA vaccine could elicit cellular and humoral immune responses which were comparable to that induced by 100 μg DNA vaccine alone. Moreover, our results demonstrate that BCG-PSN can activate TLR signaling pathways and induce Th1-type cytokines secretion. These findings suggest that BCG-PSN can serve as a novel and effective adjuvant for DNA vaccination. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Effect of heterogeneity on enhanced reductive dechlorination: Analysis of remediation efficiency and groundwater acidification

    Science.gov (United States)

    Brovelli, A.; Lacroix, E.; Robinson, C. E.; Gerhard, J.; Holliger, C.; Barry, D. A.

    2011-12-01

    Enhanced reductive dehalogenation is an attractive in situ treatment technology for chlorinated contaminants. The process includes two acid-forming microbial reactions: fermentation of an organic substrate resulting in short-chain fatty acids, and dehalogenation resulting in hydrochloric acid. The accumulation of acids and the resulting drop of groundwater pH are controlled by the mass and distribution of chlorinated solvents in the source zone, type of electron donor, alternative terminal electron acceptors available and presence of soil mineral phases able to buffer the pH (such as carbonates). Groundwater acidification may reduce or halt microbial activity, and thus dehalogenation, significantly increasing the time and costs required to remediate the aquifer. In previous work a detailed geochemical and groundwater flow simulator able to model the fermentation-dechlorination reactions and associated pH change was developed. The model accounts for the main processes influencing microbial activity and groundwater pH, including the groundwater composition, the electron donor used and soil mineral phase interactions. In this study, the model was applied to investigate how spatial variability occurring at the field scale affects dechlorination rates, groundwater pH and ultimately the remediation efficiency. Numerical simulations were conducted to examine the influence of heterogeneous hydraulic conductivity on the distribution of the injected, fermentable substrate and on the accumulation/dilution of the acidic products of reductive dehalogenation. The influence of the geometry of the DNAPL source zone was studied, as well as the spatial distribution of soil minerals. The results of this study showed that the heterogeneous distribution of the soil properties have a potentially large effect on the remediation efficiency. For examples, zones of high hydraulic conductivity can prevent the accumulation of acids and alleviate the problem of groundwater acidification. The

  13. Enhanced Efficiency in Plastic Solar Cells via Energy Matched Solution Processed NiOx Interlayers

    Energy Technology Data Exchange (ETDEWEB)

    Steirer, K. Xerxes [Colorado School of Mines, Golden, CO (United States); Ndione, Paul F. [National Renewable Energy Lab. (NREL), Golden, CO (United States). National Center for Photovoltaics; Widjonarko, N. Edwin [Univ. of Colorado, Boulder, CO (United States). Dept. of Physics; Lloyd, Matthew T. [National Renewable Energy Lab. (NREL), Golden, CO (United States). National Center for Photovoltaics; Meyer, Jens [Princeton Univ., NJ (United States). Electrical Engineering Dept.; Ratcliff, Erin L. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Chemistry and Biochemistry and Center for Interface Science: Solar Electric Materials (CISSEM); Kahn, Antoine [Princeton Univ., NJ (United States). Electrical Engineering Dept.; Armstrong, Neal R. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Chemistry and Biochemistry and Center for Interface Science: Solar Electric Materials (CISSEM); Curtis, Calvin J. [National Renewable Energy Lab. (NREL), Golden, CO (United States). National Center for Photovoltaics; Ginley, David S. [National Renewable Energy Lab. (NREL), Golden, CO (United States). National Center for Photovoltaics; Berry, Joseph J. [National Renewable Energy Lab. (NREL), Golden, CO (United States). National Center for Photovoltaics; Olson, Dana C. [National Renewable Energy Lab. (NREL), Golden, CO (United States). National Center for Photovoltaics

    2011-07-18

    We show enhanced efficiency and stability of a high performance organic solar cell (OPV) when the work-function of the hole collecting indium-tin oxide (ITO) contact, modified with a solution-processed nickel oxide (NiOx) hole-transport layer (HTL), is matched to the ionization potential of the donor material in a bulk-heterojunction solar cell. Addition of the NiOx HTL to the hole collecting contact results in a power conversion efficiency (PCE) of 6.7%, which is a 17.3% net increase in performance over the 5.7% PCE achieved with a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL on ITO. The impact of these NiOx films is evaluated through optical and electronic measurements as well as device modeling. The valence and conduction band energies for the NiOx HTL are characterized in detail through photoelectron spectroscopy studies while spectroscopic ellipsometry is used to characterize the optical properties. Oxygen plasma treatment of the NiOx HTL is shown to provide superior contact properties by increasing the ITO/NiOx contact work-function by 500 meV. Enhancement of device performance is attributed to reduction of the band edge energy offset at the ITO/NiOx interface with the poly(N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothidiazole) (PCDTBT):[6,6]-phenyl-C61 butyric acid methyl ester PCBM and [6,6]-phenyl-C71 butyric acid methyl ester (PC₇₀BM) active layer. A high work-function hole collecting contact is therefore the appropriate choice for high ionization potential donor materials in order to maximize OPV performance.

  14. Enhanced Efficiency in Plastic Solar Cells via Energy Matched Solution Processed NiOx Interlayers

    Energy Technology Data Exchange (ETDEWEB)

    Steirer, K. Xerxes; Ndione, Paul F.; Widjonarko, N. Edwin; Lloyd, Matthew T.; Meyer, Jens; Ratcliff, Erin L.; Kahn, Antoine; Armstrong, Neal R.; Curtis, Calvin J.; Ginley, David S.; Berry, Joseph J.; Olson, Dana C.

    2011-07-18

    We show enhanced efficiency and stability of a high performance organic solar cell (OPV) when the work-function of the hole collecting indium-tin oxide (ITO) contact, modified with a solution-processed nickel oxide (NiOx) hole-transport layer (HTL), is matched to the ionization potential of the donor material in a bulk-heterojunction solar cell. Addition of the NiOx HTL to the hole collecting contact results in a power conversion efficiency (PCE) of 6.7%, which is a 17.3% net increase in performance over the 5.7% PCE achieved with a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL on ITO. The impact of these NiOx films is evaluated through optical and electronic measurements as well as device modeling. The valence and conduction band energies for the NiOx HTL are characterized in detail through photoelectron spectroscopy studies while spectroscopic ellipsometry is used to characterize the optical properties. Oxygen plasma treatment of the NiOx HTL is shown to provide superior contact properties by increasing the ITO/NiOx contact work-function by 500 meV. Enhancement of device performance is attributed to reduction of the band edge energy offset at the ITO/NiOx interface with the poly(N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothidiazole) (PCDTBT):[6,6]-phenyl-C61 butyric acid methyl ester PCBM and [6,6]-phenyl-C71 butyric acid methyl ester (PC70BM) active layer. A high work-function hole collecting contact is therefore the appropriate choice for high ionization potential donor materials in order to maximize OPV performance.

  15. Methods for enhancing the efficiency of dental/oral health clinical trials: current status, future possibilities.

    Science.gov (United States)

    Barnett, M L; Pihlstrom, B L

    2004-10-01

    In recent years, there has been an increasing demand for clinical trials to study oral, dental, and craniofacial diseases and conditions. This has resulted from such factors as the increasing pace of discoveries requiring translational research to develop them for clinical use, FDA requirements for product approval, a need for additional data to support evidence-based dental practice, and the expansion of the NIDCR's clinical research programs. The complexity, size, and duration of clinical trials often make them quite costly to conduct, and may impede the development of novel diagnostic, preventive, and therapeutic methods that could have a significant impact on clinical practice and inform public health policy. Recent advances in such areas as genomics and proteomics, coupled with the development of new technologies, have expanded our knowledge of the etiology and pathogenesis of disease and, from this, have provided new insights into the design and conduct of clinical trials. The workshop, "Methods for Enhancing the Efficiency of Dental/Oral Health Clinical Trials: Current Status, Future Possibilities", held on May 6-7, 2004, considered a variety of ways in which these insights are being, or have the potential to be, applied to clinical trials so as to enhance their efficiency and, hence, their cost-effectiveness, without diminishing the quality of information produced. The focus of this workshop was to assess the state of the science and identify research needs for the use of biomarkers, surrogate endpoints, and new technologies in oral disease clinical trials. Examples of ways in which clinical trials of other diseases have benefited from the use of new methods and technologies and FDA considerations were also discussed.

  16. Enhanced-efficiency fertilizers are not a panacea for resolving the nitrogen problem.

    Science.gov (United States)

    Li, Tingyu; Zhang, Weifeng; Yin, Jiao; Chadwick, David; Norse, David; Lu, Yuelai; Liu, Xuejun; Chen, Xinping; Zhang, Fusuo; Powlson, David; Dou, Zhengxia

    2017-10-03

    Improving nitrogen (N) management for greater agricultural output while minimizing unintended environmental consequences is critical in the endeavor of feeding the growing population sustainably amid climate change. Enhanced-efficiency fertilizers (EEFs) have been developed to better synchronize fertilizer N release with crop uptake, offering the potential for enhanced N use efficiency (NUE) and reduced losses. Can EEFs play a significant role in helping address the N management challenge? Here we present a comprehensive analysis of worldwide studies published in 1980-2016 evaluating four major types of EEFs (polymer-coated fertilizers PCF, nitrification inhibitors NI, urease inhibitors UI, and double inhibitors DI, i.e. urease and nitrification inhibitors combined) regarding their effectiveness in increasing yield and NUE and reducing N losses. Overall productivity and environmental efficacy depended on the combination of EEF type and cropping systems, further affected by biophysical conditions. Best scenarios include: (i) DI used in grassland (n = 133), averaging 11% yield increase, 33% NUE improvement, and 47% decrease in aggregated N loss (sum of NO3- , NH3 , and N2 O, totaling 84 kg N/ha); (ii) UI in rice-paddy systems (n = 100), with 9% yield increase, 29% NUE improvement, and 41% N-loss reduction (16 kg N/ha). EEF efficacies in wheat and maize systems were more complicated and generally less effective. In-depth analysis indicated that the potential benefits of EEFs might be best achieved when a need is created, for example, by downward adjusting N application from conventional rate. We conclude that EEFs can play a significant role in sustainable agricultural production but their prudent use requires firstly eliminating any fertilizer mismanagement plus the implementation of knowledge-based N management practices. © 2017 John Wiley & Sons Ltd.

  17. Adaptive Splitting Integrators for Enhancing Sampling Efficiency of Modified Hamiltonian Monte Carlo Methods in Molecular Simulation.

    Science.gov (United States)

    Akhmatskaya, Elena; Fernández-Pendás, Mario; Radivojević, Tijana; Sanz-Serna, J M

    2017-10-24

    The modified Hamiltonian Monte Carlo (MHMC) methods, i.e., importance sampling methods that use modified Hamiltonians within a Hybrid Monte Carlo (HMC) framework, often outperform in sampling efficiency standard techniques such as molecular dynamics (MD) and HMC. The performance of MHMC may be enhanced further through the rational choice of the simulation parameters and by replacing the standard Verlet integrator with more sophisticated splitting algorithms. Unfortunately, it is not easy to identify the appropriate values of the parameters that appear in those algorithms. We propose a technique, that we call MAIA (Modified Adaptive Integration Approach), which, for a given simulation system and a given time step, automatically selects the optimal integrator within a useful family of two-stage splitting formulas. Extended MAIA (or e-MAIA) is an enhanced version of MAIA, which additionally supplies a value of the method-specific parameter that, for the problem under consideration, keeps the momentum acceptance rate at a user-desired level. The MAIA and e-MAIA algorithms have been implemented, with no computational overhead during simulations, in MultiHMC-GROMACS, a modified version of the popular software package GROMACS. Tests performed on well-known molecular models demonstrate the superiority of the suggested approaches over a range of integrators (both standard and recently developed), as well as their capacity to improve the sampling efficiency of GSHMC, a noticeable method for molecular simulation in the MHMC family. GSHMC combined with e-MAIA shows a remarkably good performance when compared to MD and HMC coupled with the appropriate adaptive integrators.

  18. High throughput virtual screening and in silico ADMET analysis for rapid and efficient identification of potential PAP248-286 aggregation inhibitors as anti-HIV agents

    Science.gov (United States)

    Malik, Ruchi; Bunkar, Devendra; Choudhary, Bhanwar Singh; Srivastava, Shubham; Mehta, Pakhuri; Sharma, Manish

    2016-10-01

    Human semen is principal vehicle for transmission of HIV-1 and other enveloped viruses. Several endogenous peptides present in semen, including a 39-amino acid fragments of prostatic acid phosphatase (PAP248-286) assemble into amyloid fibrils named as semen-derived enhancer of viral infection (SEVI) that promote virion attachment to target cells which dramatically enhance HIV virus infection by up to 105-fold. Epigallocatechin-3-gallate (EGCG), a polyphenolic compound, is the major catechin found in green tea which disaggregates existing SEVI fibers, and inhibits the formation of SEVI fibers. The aim of this study was to screen a number of relevant polyphenols to develop a rational approach for designing PAP248-286 aggregation inhibitors as potential anti-HIV agents. The molecular docking based virtual screening results showed that polyphenolic compounds 2-6 possessed good docking score and interacted well with the active site residues of PAP248-286. Amino acid residues of binding site namely; Lys255, Ser256, Leu258 and Asn265 are involved in binding of these compounds. In silico ADMET prediction studies on these hits were also found to be promising. Polyphenolic compounds 2-6 identified as hits may act as novel leads for inhibiting aggregation of PAP248-286 into SEVI.

  19. The determinants of technical efficiency of a large scale HIV prevention project: application of the DEA double bootstrap using panel data from the Indian Avahan.

    Science.gov (United States)

    Lépine, Aurélia; Vassall, Anna; Chandrashekar, Sudhashree

    2015-01-01

    In 2004, the largest HIV prevention project (Avahan) conducted globally was implemented in India. Avahan was implemented by NGOs supported by state lead partners in order to provide HIV prevention services to high-risk population groups. In 2007, most of the NGOs reached full coverage. Using a panel data set of the NGOs that implemented Avahan, we investigate the level of technical efficiency as well as the drivers of technical inefficiency by using the double bootstrap procedure developed by Simar & Wilson (2007). Unlike the two-stage traditional method, this method allows valid inference in the presence of measurement error and serial correlation. We find that over the 4 years, Avahan NGOs could have reduced the level of inputs by 43% given the level of outputs reached. We find that efficiency of the project has increased over time. Results indicate that main drivers of inefficiency come from the characteristics of the state lead partner, the NGOs and the catchment area. These organisational factors are important to explicitly consider and assess when designing and implementing HIV prevention programmes and in setting benchmarks in order to optimise the use and allocation of resources. C14, I1.

  20. Nonlinear predictive control for durability enhancement and efficiency improvement in a fuel cell power system

    Science.gov (United States)

    Luna, Julio; Jemei, Samir; Yousfi-Steiner, Nadia; Husar, Attila; Serra, Maria; Hissel, Daniel

    2016-10-01

    In this work, a nonlinear model predictive control (NMPC) strategy is proposed to improve the efficiency and enhance the durability of a proton exchange membrane fuel cell (PEMFC) power system. The PEMFC controller is based on a distributed parameters model that describes the nonlinear dynamics of the system, considering spatial variations along the gas channels. Parasitic power from different system auxiliaries is considered, including the main parasitic losses which are those of the compressor. A nonlinear observer is implemented, based on the discretised model of the PEMFC, to estimate the internal states. This information is included in the cost function of the controller to enhance the durability of the system by means of avoiding local starvation and inappropriate water vapour concentrations. Simulation results are presented to show the performance of the proposed controller over a given case study in an automotive application (New European Driving Cycle). With the aim of representing the most relevant phenomena that affects the PEMFC voltage, the simulation model includes a two-phase water model and the effects of liquid water on the catalyst active area. The control model is a simplified version that does not consider two-phase water dynamics.

  1. Dimensional scale effects on surface enhanced Raman scattering efficiency of self-assembled silver nanoparticle clusters

    Energy Technology Data Exchange (ETDEWEB)

    Fasolato, C. [Dip. Fisica, Università Sapienza, P.le Aldo Moro, 5, 00185 Rome (Italy); Center for Life Nanoscience@Sapienza, Istituto Italiano di Tecnologia, V.le Regina Elena, 291, 00185 Rome (Italy); Domenici, F., E-mail: fabiodomenici@gmail.com, E-mail: paolo.postorino@roma1.infn.it; De Angelis, L.; Luongo, F.; Postorino, P., E-mail: fabiodomenici@gmail.com, E-mail: paolo.postorino@roma1.infn.it [Dip. Fisica, Università Sapienza, P.le Aldo Moro, 5, 00185 Rome (Italy); Sennato, S. [Dip. Fisica, Università Sapienza, P.le Aldo Moro, 5, 00185 Rome (Italy); CNR-IPCS UOS Roma, Dip. Fisica, Università Sapienza, P.le Aldo Moro, 5, 00185 Rome (Italy); Mura, F. [Dip. Scienze di Base Applicate all' Ingegneria, Università Sapienza, Via A. Scarpa, 16, 00185 Rome (Italy); Costantini, F. [Dip. Ingegneria Astronautica Elettrica ed Energetica, Università Sapienza, Via Eudossiana, 18, 00184 Rome (Italy); Bordi, F. [Dip. Fisica, Università Sapienza, P.le Aldo Moro, 5, 00185 Rome (Italy); Center for Life Nanoscience@Sapienza, Istituto Italiano di Tecnologia, V.le Regina Elena, 291, 00185 Rome (Italy); CNR-IPCS UOS Roma, Dip. Fisica, Università Sapienza, P.le Aldo Moro, 5, 00185 Rome (Italy)

    2014-08-18

    A study of the Surface Enhanced Raman Scattering (SERS) from micrometric metallic nanoparticle aggregates is presented. The sample is obtained from the self-assembly on glass slides of micro-clusters of silver nanoparticles (60 and 100 nm diameter), functionalized with the organic molecule 4-aminothiophenol in water solution. For nanoparticle clusters at the micron scale, a maximum enhancement factor of 10{sup 9} is estimated from the SERS over the Raman intensity ratio normalized to the single molecule contribution. Atomic force microscopy, correlated to spatially resolved Raman measurements, allows highlighting the connection between morphology and efficiency of the plasmonic system. The correlation between geometric features and SERS response of the metallic structures reveals a linear trend of the cluster maximum scattered intensity as a function of the surface area of the aggregate. On given clusters, the intensity turns out to be also influenced by the number of stacking planes of the aggregate, thus suggesting a plasmonic waveguide effect. The linear dependence results weakened for the largest area clusters, suggesting 30 μm{sup 2} as the upper limit for exploiting the coherence over large scale of the plasmonic response.

  2. Influence of enhancing electrolytes on the removal efficiency of heavy metals from Gabes marine sediments (Tunisia).

    Science.gov (United States)

    Missaoui, Amel; Said, Imen; Lafhaj, Zoubeir; Hamdi, Essaieb

    2016-12-15

    This study focused on the feasibility of the treatment of heavy metals-contaminated sediments from Gabes harbor (Tunisia) using enhanced electrokinetic process. It presented a laboratory short-time electrokinetic experiment. The enhancing agents, as citric, acetic acids and sodium dodecyl sulfate (SDS) were used regarding their low environmental hazard. The electrokinetic cell was specially designed in order to elaborate two experiments at the same time. This paper is composed of three parts. The first part introduces the characterization of Gabes sediments. The second part describes the design of laboratory electrokinetic cell and the followed methods. The third part is dedicated to the results analysis. Treatment efficiency revealed that more than 80% of lead was removed from Gabes marine sediments. The reduction of cooper concentration, in sediments after treatment, ranged from 74 to 87%. Despite, the high removal of cadmium that ranged from 58 to 79%, treated sediments presented Cd concentration above the threshold limit. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Microalgae pretreatment with liquid hot water to enhance enzymatic hydrolysis efficiency.

    Science.gov (United States)

    Yuan, Tao; Li, Xiekun; Xiao, Shiyuan; Guo, Ying; Zhou, Weizheng; Xu, Jingliang; Yuan, Zhenhong

    2016-11-01

    Nowadays, microalgae are being considered as promising raw material for bioethanol production. In this work, three process variables during liquid hot water (LHW) pretreatment prior to enzymatic hydrolysis by response surface methodology on Scenedesmus sp. WZKMT were investigated to enhance glucose recovery. Results indicated that the order of significance for three parameters was temperature>solid-to-liquid ratio>time. The optimal condition was 1:13 (w/v), 147°C and 40min. The concentration and recovery of glucose under this condition were 14.223g·L(-1) and 89.32%, respectively, which were up to 5-fold higher than the samples without LHW pretreatment. In addition, the surface morphologies of microalgae cells before and after LHW pretreatment were also verified using scanning electron microscopy (SEM). LHW pretreatment can greatly enhance the enzymatic efficiency, and can be regarded as an ideal pretreatment method for glucose recovery from microalgae. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. A MultiAir®/MultiFuel Approach to Enhancing Engine System Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Reese, Ronald [Chrysler Group LLC., Auburn Hills, MI (United States)

    2015-05-20

    FCA US LLC (formally known as Chrysler Group LLC, and hereinafter “Chrysler”) was awarded an American Recovery and Reinvestment Act (ARRA) funded project by the Department of Energy (DOE) titled “A MultiAir®/MultiFuel Approach to Enhancing Engine System Efficiency” (hereinafter “project”). This award was issued after Chrysler submitted a proposal for Funding Opportunity Announcement DE-FOA- 0000079, “Systems Level Technology Development, Integration, and Demonstration for Efficient Class 8 Trucks (SuperTruck) and Advanced Technology Powertrains for Light-Duty Vehicles (ATP-LD).” Chrysler started work on this project on June 01, 2010 and completed testing activities on August 30, 2014. Overall objectives of this project were; Demonstrate a 25% improvement in combined Federal Test Procedure (FTP) City and Highway fuel economy over a 2009 Chrysler minivan; Accelerate the development of highly efficient engine and powertrain systems for light-duty vehicles, while meeting future emissions standards; and Create and retain jobs in accordance with the American Recovery and Reinvestment Act of 2009

  5. Flow Pickering Emulsion Interfaces Enhance Catalysis Efficiency and Selectivity for Cyclization of Citronellal.

    Science.gov (United States)

    Chen, Huan; Zou, Houbing; Hao, Yajuan; Yang, Hengquan

    2017-05-09

    Cyclization of citronellal is a necessary intermediate step to produce the important flavor chemical (-)-menthol. Here, a continuous-flow Pickering emulsion (FPE) strategy for selective cyclization of citronellal to (-)-isopulegol by using water droplets hosting a heteropolyacid (HPA) catalyst to fill a column reactor is demonstrated. Owing to the large liquid-liquid interface and the excellent confinement ability of droplets toward HPA, the FPE system exhibited a much higher catalysis efficiency than its batch counterpart (2-5-fold) and an excellent durability (two months). Moreover, a remarkably enhanced selectivity was observed from 34.8 % for batch reactions to 64 % for the FPE reactions. It was found that the water droplet size and the flow rate significantly impact the catalysis selectivity and efficiency. This study not only represents an unprecedented and sustainable process for the selective cyclization of citronellal but also demonstrates a new flow-interface catalysis effect that can be useful for designing innovative catalysis systems in the future. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Efficiency Enhancement of Cocktail Dye of Ixora coccinea and Tradescantia spathacea in DSSC

    Science.gov (United States)

    Zolkepli, Zularif; Lim, Andery; Ekanayake, Piyasiri; Tennakoon, Kushan

    2015-01-01

    The use of anthocyanin dyes extracted from epidermal leaves of Tradescantia spathacea (Trant) and petals of Ixora coccinea (IX) was evaluated in the application of dye-sensitized solar cells (DSSCs). Subsequently, cocktail anthocyanin dyes from these dyes were prepared and how they enhanced the cell's overall performance was assessed using five different volume-to-volume ratios. Cocktail dyes absorbed a wider range of light in the visible region, thus increasing the cell efficiencies of the cocktail dyes when compared to the DSSC sensitized by individual dyes. The surface charge (zeta-potential), average size of aggregated anthocyanin molecules (zetasizer), and anthocyanin stability in different storage temperatures were analyzed and recorded. Lower size of aggregated dye molecules as revealed from the cocktail dyes ensured better adsorption onto the TiO2 film. Tradescantia/Ixora pigments mixed in 1 : 4 ratio showed the highest cell efficiency of η = 0.80%, under the irradiance of 100 mW cm−2, with a short-circuit current density 4.185 mA/cm2, open-circuit voltage of 0.346 V, and fill factor of 0.499. It was found that the desired storage temperature for these cocktail dyes to be stable over time was −20°C, in which the anthocyanin half-life was about approximately 1727 days. PMID:26793239

  7. Efficiency Enhancement of Cocktail Dye of Ixora coccinea and Tradescantia spathacea in DSSC

    Directory of Open Access Journals (Sweden)

    Zularif Zolkepli

    2015-01-01

    Full Text Available The use of anthocyanin dyes extracted from epidermal leaves of Tradescantia spathacea (Trant and petals of Ixora coccinea (IX was evaluated in the application of dye-sensitized solar cells (DSSCs. Subsequently, cocktail anthocyanin dyes from these dyes were prepared and how they enhanced the cell’s overall performance was assessed using five different volume-to-volume ratios. Cocktail dyes absorbed a wider range of light in the visible region, thus increasing the cell efficiencies of the cocktail dyes when compared to the DSSC sensitized by individual dyes. The surface charge (zeta-potential, average size of aggregated anthocyanin molecules (zetasizer, and anthocyanin stability in different storage temperatures were analyzed and recorded. Lower size of aggregated dye molecules as revealed from the cocktail dyes ensured better adsorption onto the TiO2 film. Tradescantia/Ixora pigments mixed in 1 : 4 ratio showed the highest cell efficiency of η=0.80%, under the irradiance of 100 mW cm−2, with a short-circuit current density 4.185 mA/cm2, open-circuit voltage of 0.346 V, and fill factor of 0.499. It was found that the desired storage temperature for these cocktail dyes to be stable over time was −20°C, in which the anthocyanin half-life was about approximately 1727 days.

  8. Enhanced thermoelectric efficiency via orthogonal electrical and thermal conductances in phosphorene.

    Science.gov (United States)

    Fei, Ruixiang; Faghaninia, Alireza; Soklaski, Ryan; Yan, Jia-An; Lo, Cynthia; Yang, Li

    2014-11-12

    Thermoelectric devices that utilize the Seebeck effect convert heat flow into electrical energy and are highly desirable for the development of portable, solid state, passively powered electronic systems. The conversion efficiencies of such devices are quantified by the dimensionless thermoelectric figure of merit (ZT), which is proportional to the ratio of a device's electrical conductance to its thermal conductance. In this paper, a recently fabricated two-dimensional (2D) semiconductor called phosphorene (monolayer black phosphorus) is assessed for its thermoelectric capabilities. First-principles and model calculations reveal not only that phosphorene possesses a spatially anisotropic electrical conductance, but that its lattice thermal conductance exhibits a pronounced spatial-anisotropy as well. The prominent electrical and thermal conducting directions are orthogonal to one another, enhancing the ratio of these conductances. As a result, ZT may reach the criterion for commercial deployment along the armchair direction of phosphorene at T = 500 K and is close to 1 even at room temperature given moderate doping (∼2 × 10(16) m(-2) or 2 × 10(12) cm(-2)). Ultimately, phosphorene hopefully stands out as an environmentally sound thermoelectric material with unprecedented qualities. Intrinsically, it is a mechanically flexible material that converts heat energy with high efficiency at low temperatures (∼300 K), one whose performance does not require any sophisticated engineering techniques.

  9. A knee-mounted biomechanical energy harvester with enhanced efficiency and safety

    Science.gov (United States)

    Chen, Chao; Chau, Li Yin; Liao, Wei-Hsin

    2017-06-01

    Energy harvesting is becoming a major limiting issue for many portable devices. When undertaking any activity, the human body generates a significant amount of biomechanical energy, which can be collected by means of a portable energy harvester. This energy provides a method of powering portable devices such as prosthetic limbs. In this paper, a knee-mounted energy harvester with enhanced efficiency and safety is proposed and developed to convert mechanical energy into electricity during human motion. This device can change the bi-directional knee input into uni-directional rotation for an electromagnetic generator using a specially designed transmission system. Without the constraint of induced impact on the human body, this device can harvest biomechanical energy from both knee flexion and extension, improving the harvesting efficiency over previous single-direction energy harvesters. It can also provide protection from device malfunction, and increase the safety of current biomechanical energy harvesters. A highly compact and light prototype is developed taking into account human kinematics. The biomechanical energy harvesting system is also modeled and analyzed. The prototype is tested under different conditions including walking, running and climbing stairs, to evaluate the energy harvesting performance and effect on the human gait. The experimental results show that the prototype can harvest an average power of 3.6 W at 1.5 m s-1 walking speed, which is promising for portable electronic devices.

  10. Adaptive tool servo diamond turning for enhancing machining efficiency and surface quality of freeform optics.

    Science.gov (United States)

    Zhu, Zhiwei; To, Suet

    2015-08-10

    Fast tool servo/ slow tool servo (FTS/STS) diamond turning is a very promising technique for the generation of freeform optics. However, the currently adopted constant scheme for azimuth sampling and side-feeding motion possesses no adaptation to surface shape variation, leading to the non-uniform surface quality and low machining efficiency. To overcome this defect, this paper reports on a novel adaptive tool servo (ATS) diamond turning technique which is essentially based on the novel two-degree-of-freedom (2-DOF) FTS/STS. In the ATS, the sampling interval and the side-feeding motion are actively controlled at any cutting point to adapt the machining process to shape variation of the desired surface, making both the sampling induced interpolation error and the side-feeding induced residual tool mark be within the desired tolerances. Characteristic of the required cutting motion suggests that besides the conventional z-axis servo motion, another servo motion along the x-axis synthesizing by the c-axis is mandatory for implementing the ATS. Comparative studies of surface generation of typical micro-structured surfaces in FTS/STS and ATS are thoroughly conducted both theoretically and experimentally. The result demonstrates that the ATS outperforms the FTS/STS with improved surface quality while simultaneously enhanced machining efficiency.

  11. Enhanced pathway efficiency of Saccharomyces cerevisiae by introducing thermo-tolerant devices.

    Science.gov (United States)

    Liu, Yueqin; Zhang, Genli; Sun, Huan; Sun, Xiangying; Jiang, Nisi; Rasool, Aamir; Lin, Zhanglin; Li, Chun

    2014-10-01

    In this study, thermo-tolerant devices consisting of heat shock genes from thermophiles were designed and introduced into Saccharomyces cerevisiae for improving its thermo-tolerance. Among ten engineered thermo-tolerant yeasts, T.te-TTE2469, T.te-GroS2 and T.te-IbpA displayed over 25% increased cell density and 1.5-4-fold cell viability compared with the control. Physiological characteristics of thermo-tolerant strains revealed that better cell wall integrity, higher trehalose content and enhanced metabolic energy were preserved by thermo-tolerant devices. Engineered thermo-tolerant strain was used to investigate the impact of thermo-tolerant device on pathway efficiency by introducing β-amyrin synthesis pathway, showed 28.1% increased β-amyrin titer, 28-35°C broadened growth temperature range and 72h shortened fermentation period. The results indicated that implanting heat shock proteins from thermophiles to S. cerevisiae would be an efficient approach to improve its thermo-tolerance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Transmitted/founder and chronic subtype C HIV-1 use CD4 and CCR5 receptors with equal efficiency and are not inhibited by blocking the integrin α4β7.

    Directory of Open Access Journals (Sweden)

    Nicholas F Parrish

    Full Text Available Sexual transmission of human immunodeficiency virus type 1 (HIV-1 most often results from productive infection by a single transmitted/founder (T/F virus, indicating a stringent mucosal bottleneck. Understanding the viral traits that overcome this bottleneck could have important implications for HIV-1 vaccine design and other prevention strategies. Most T/F viruses use CCR5 to infect target cells and some encode envelope glycoproteins (Envs that contain fewer potential N-linked glycosylation sites and shorter V1/V2 variable loops than Envs from chronic viruses. Moreover, it has been reported that the gp120 subunits of certain transmitted Envs bind to the gut-homing integrin α4β7, possibly enhancing virus entry and cell-to-cell spread. Here we sought to determine whether subtype C T/F viruses, which are responsible for the majority of new HIV-1 infections worldwide, share biological properties that increase their transmission fitness, including preferential α4β7 engagement. Using single genome amplification, we generated panels of both T/F (n = 20 and chronic (n = 20 Env constructs as well as full-length T/F (n = 6 and chronic (n = 4 infectious molecular clones (IMCs. We found that T/F and chronic control Envs were indistinguishable in the efficiency with which they used CD4 and CCR5. Both groups of Envs also exhibited the same CD4+ T cell subset tropism and showed similar sensitivity to neutralization by CD4 binding site (CD4bs antibodies. Finally, saturating concentrations of anti-α4β7 antibodies failed to inhibit infection and replication of T/F as well as chronic control viruses, although the growth of the tissue culture-adapted strain SF162 was modestly impaired. These results indicate that the population bottleneck associated with mucosal HIV-1 acquisition is not due to the selection of T/F viruses that use α4β7, CD4 or CCR5 more efficiently.

  13. Effects of biochar on enhanced nutrient use efficiency of green bean, Vigna radiata L.

    Science.gov (United States)

    Prapagdee, Songkrit; Tawinteung, Nukoon

    2017-04-01

    Biochar is the carbonized material produced from biomass and is used in several environmental applications. The biochar characteristics depend on the carbonization conditions and feedstock. The suitability of a given biochar for soil improvement depends on the biochar characteristics, soil properties, and target plants. Biochar has been applied at 1-20% (w/w) in the soil, but currently there is a lack of information on what type and concentration of biochar are most suitable for a specific plant and soil quality. Too much biochar will reduce plant growth because of the high alkalinity of biochar, which will cause long-term soil alkalinity. In contrast, too little biochar might be insufficient to enhance plant productivity. In this study, a suitable concentration of cassava stem (an abundant agricultural waste in Thailand) biochar produced at 350 °C was evaluated for green bean (Vigna radiata L.) growth from germination to seed production in pots over 8 weeks. The soil fertility was increased with increasing biochar concentration. At 5% (w/w) biochar, the soil fertility and plant growth were significantly enhanced, while 10% (w/w) biochar significantly enhanced bean growth and bean pod production. The increased biochar concentration in the soil significantly increased the soil total nitrogen and extractable potassium (K) levels but did not affect the amount of available phosphorous. Biochar at 10% (w/w) significantly induced the accumulation of K in the stems, leaves, nut shells, and roots but not in nut seeds. Moreover, biochar not only increased the K concentration in soil but also increased the plant nutrient use efficiency of K, which is important for plant growth. Graphical abstract ᅟ.

  14. NARINGENIN ENHANCED EFFICIENCY OF GUS ACTIVITY IN Passiflora mollissima (H.B.K. Bailey

    Directory of Open Access Journals (Sweden)

    G.O. Cancino

    2004-06-01

    Full Text Available The flavonoid naringenin has been investigated as a possible vir gene inducer in Agrobacterium-mediated transformation in Passiflora mollissima, P. giberti and Nicotiana tabacum cv. Xanthi. The transformation efficiency percentage of explants showing blue GUS expression and the extent of staining following inoculation with Agrobacterium tumefaciens strains EHA 105 and 1065, carrying gus and nptII genes was enhanced with the supplementation of the co-cultivation medium with naringenin. Supplementation of medium with 100µM (strain EHA 105 and 300 µM (strain 1065 naringenin was most effective at enhancing mean (±s.e.m., n=3 GUS activity in leaf explants (20.3 ± 2.4%, strain EHA; 105; 6.0 ± 0.57%, strain 1065 and nodal segments (16.7 ± 2.4% strain EHA 105; 8.3 ± 0.57% strain 1065 of P. mollissima. In P. giberti and N. tabacum maximum GUS activity was obtained in leaf and root explants with 100µM naringenin for both strains analysed. Additionally, when naringenin was added to Luria Bertani (LB medium, both bacterial growth via optical density and colony forming units were higher when compared to control. This is the first report of the use of naringenin to enhance gene transfer from Agrobacterium to plants. These findings suggest that naringenin can be used as an alternative to acetosyringone for vir gene induction in Agrobacterium. This approach may be especially useful in plants that are generally recalcitrant to Agrobacterium-mediatedtransformation.

  15. Synthesis of novel chitosan–silica/CpG oligodeoxynucleotide nanohybrids with enhanced delivery efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Song, E-mail: CHEN.Song@nims.go.jp [JSPS Research Fellow, 8 Ichibancho, Chiyoda-ku, Tokyo 102-8472 (Japan); Biomaterials Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Zhang, Huijie [Biomaterials Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Graduate School of Life Science, Hokkaido University, N10W8, Kita-ku, Sapporo 060-0812 (Japan); Chinnathambi, Shanmugavel [Biomaterials Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Department of Medical Physics, Anna University, Chennai 600-025 (India); Hanagata, Nobutaka, E-mail: HANAGATA.Nobutaka@nims.go.jp [Biomaterials Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Graduate School of Life Science, Hokkaido University, N10W8, Kita-ku, Sapporo 060-0812 (Japan); Nanotechnology Innovation Station, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan)

    2013-08-01

    Chitosan–silica/CpG oligodeoxynucleotide (ODN) nanohybrids were synthesized to stimulate Toll-like receptor 9-mediated induction of interleukin-6 (IL-6). The chitosan–silica hybrid was first synthesized from a mixture of chitosan and 3-glycidoxypropyl trimethoxysilane under acidic conditions via a sol–gel process, and then used to condense CpG ODN2006x3-PD to yield chitosan–silica/CpG ODN nanohybrids. Scanning electron microscopy and atomic force microscopy showed that the chitosan–silica/CpG ODN nanohybrids had an elliptic shape with a diameter of 100–200 nm. After soaking in HAc–NaAc buffer solution (pH 5.5), the nanohybrids exhibited sustained release of CpG ODN. When the nanohybrids were separately exposed to 293XL-hTLR9 cells and peripheral blood mononuclear cells, no significant toxicity was observed. An immunochemical assay for cellular uptake revealed that the nanohybrids were taken up by the cells and located in endolysosomes. An enzyme-linked immunosorbent assay for cytokines indicated that the nanohybrids effectively stimulated the induction of IL-6. Chitosan–silica/CpG ODN nanohybrids underwent cellular uptake and enhanced induction of IL-6 to a greater degree than conventional chitosan/CpG ODN nanocomplexes, indicating that they have an enhanced delivery efficiency. - Highlights: • Chitosan-silica/CpG ODN nanohybrids (100 nm–200 nm) were synthesized. • Nanohybrids exhibited a sustained release behavior for CpG ODN. • Cellular uptake of nanohybrids was enhanced due to presence of silica. • The released CpG ODN stimulated production of cell cytokine.

  16. STIMULI-RESPONSIVE POLYMERS WITH ENHANCED EFFICIENCY IN RESERVOIR RECOVERY PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    Charles McCormick; Roger Hester

    2004-09-30

    This sixth and final progress report for DOE Award Number DE-FC26-01BC15317 describes research during the period March 01, 2004 through August 31, 2004 performed at the University of Southern Mississippi on ''Stimuli Responsive Polymers with Enhanced Efficiency in Reservoir Recovery'' processes. Significantly, terpolymers that are responsive to changes in pH and ionic strength have been synthesized, characterized, and their solution properties have been extensively examined. Terpolymers composed of acrylamide, a carboxylated acrylamido monomer (AMBA), and a quaternary ammonium monomer (AMBATAC) with balanced compositions of the latter two, exhibit increases in aqueous solution viscosity as NaCl concentration is increased. This increase in polymer coil size can be expected upon injection of this type of polymer into oil reservoirs of moderate-to-high salinity, leading to better mobility control. The opposite effect (loss of viscosity) is observed for conventional polymer systems. Additionally polymer mobility characteristics have been conducted for a number of hydrophilic copolymers utilizing an extensional flow apparatus and size exclusion chromatography. This study reveled that oil recovery enhancement through use of polymers in a water flood is due to the polymer's resistance to deformation as it flows through the reservoir. Individual polymers when in aqueous solution form coils. The larger the polymer's coil size, the greater the polymer's resistance to extensional flow and the more effective the polymer is in enhancing oil recovery. Large coil sizes are obtained by increasing the polymer molecular weight and having macromolecular structures that favor greater swelling of the coil by the aqueous solvent conditions (temperature, pH and electrolyte concentration) existing in the reservoir.

  17. Time-efficient myocardial contrast partition coefficient measurement from early enhancement with magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Shi-Jun Zhang

    Full Text Available OBJECTIVE: Our purpose was to validate an early enhancement time point for accurately measuring the myocardial contrast partition coefficient (lambda using dynamic-equilibrium magnetic resonance imaging. MATERIALS AND METHODS: The pre- and post-contrast longitudinal relaxation rates (reciprocal of T1 of the interventricular septum (R1(m and blood pool (R1(b were obtained from fifteen healthy volunteers and three diabetic patients with hypertension using two optimized T1 mapping sequences (modified Look-Locker inversion recovery on a 3-Tesla magnetic resonance scanner. Reference lambda values were calculated as the slope of the regression line of R1(m versus R1(b at dynamic equilibrium (multi-point regression method. The simplified pre-/post-enhancement two-acquisition method (two-point method was used to calculate lambda by relating the change in R1(m and R1(b using different protocols according to the acquisition stage of the post-enhancement data point. The agreement with the referential method was tested by calculating Pearson's correlation coefficient and the intra-class correlation coefficient. RESULTS: The lambda values measured by the two-point method increased (from 0.479 ± 0.041 to 0.534 ± 0.043 over time from 6 to 45 minutes after contrast and exhibited good correlation with the reference at each time point (r ≥ 0.875, p<0.05. The intra-class correlation coefficient on absolute agreement with the reference lambda was 0.946, 0.929 and 0.922 at the 6th, 7th and 8th minutes and dropped from 0.878 to 0.403 from the 9th minute on. CONCLUSIONS: The time-efficient two-point method at 6-8 minutes after the Gd-DTPA bolus injection exhibited good agreement with the multi-point regression method and can be applied for accurate lambda measurement in normal myocardium.

  18. Thermal Stability-Enhanced and High-Efficiency Planar Perovskite Solar Cells with Interface Passivation.

    Science.gov (United States)

    Zhang, Weihai; Xiong, Juan; Jiang, Li; Wang, Jianying; Mei, Tao; Wang, Xianbao; Gu, Haoshuang; Daoud, Walid A; Li, Jinhua

    2017-11-08

    As the electron transport layer (ETL) of perovskite solar cells, oxide semiconductor zinc oxide (ZnO) has been attracting great attention due to its relatively high mobility, optical transparency, low-temperature fabrication, and good environment stability. However, the nature of ZnO will react with the patron on methylamine, which would deteriorate the performance of cells. Although many methods, including high-temperature annealing, doping, and surface modification, have been studied to improve the efficiency and stability of perovskite solar cells with ZnO ETL, devices remain relatively low in efficiency and stability. Herein, we adopted a novel multistep annealing method to deposit a porous PbI 2 film and improved the quality and uniformity of perovskite films. The cells with ZnO ETL were fabricated at the temperature of <150 °C by solution processing. The power conversion efficiency (PCE) of the device fabricated by the novel annealing method increased from 15.5 to 17.5%. To enhance the thermal stability of CH 3 NH 3 PbI 3 (MAPbI 3 ) on the ZnO surface, a thin layer of small molecule [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) was inserted between the ZnO layer and perovskite film. Interestingly, the PCE of PCBM-passivated cells could reach nearly 19.1%. To our best knowledge, this is the highest PCE value of ZnO-based perovskite solar cells until now. More importantly, PCBM modification could effectively suppress the decomposition of MAPbI 3 and improve the thermal stability of cells. Therefore, the ZnO is a promising candidate of electron transport material for perovskite solar cells in future applications.

  19. Enhanced conversion efficiency in nanocrystalline solar cells using optically functional patterns

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yang Doo; Park, Sang Jun [Department of Materials and Science Engineering, Korea University, 5-1 Anam-dong, Sungbuk-Gu, Seoul 136-701 (Korea, Republic of); Jang, Eunseok [Photovoltaic Laboratory, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Oh, Kyoung Suk [KIER-UNIST Advanced Center for Energy, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Cho, Jun-Sik, E-mail: jscho@kier.re.kr [Photovoltaic Laboratory, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Lee, Heon, E-mail: heonlee@korea.ac.kr [Department of Materials and Science Engineering, Korea University, 5-1 Anam-dong, Sungbuk-Gu, Seoul 136-701 (Korea, Republic of)

    2015-07-31

    The lower conversion efficiency of nanocrystalline silicon (nc-Si:H) solar cells is a result of its lower photon absorption capability of nc-Si:H. To increase photon absorption of nc-Si:H, the Ag substrates were fabricated with optically functional patterns. Two types of patterns, with random and regular structures, were formed by direct imprint technology. Owing to these optically functional patterns, the scattering of reflected light at the surface of the patterned Ag was enhanced and the optical path became longer. Thus, a greater amount of photons was absorbed by the nc-Si:H layer. Compared to flat Ag (without a surface pattern), the light absorption value of the nc-Si:H layer with a random structure pattern was increased at wavelengths ranging from 600 to 1100 nm. In the case of the regular patterned Ag, the light absorption value of the nc-Si:H layer was higher than the flat Ag at 300 to 1100 nm. Subsequently, nc-Si:H solar cells constructed on the optically functional pattern exhibit a 15.7% higher J{sub sc} value and a 19.5% higher overall conversion efficiency, compared to an identical solar cell on flat Ag. - Highlights: • Optically functional patterns were fabricated by direct printing technique. • The light absorption of solar cells was increased by the patterned Ag substrate. • Current density of solar cells on patterned Ag increased by approximately 15.7%. • The efficiency of solar cells on patterned Ag increased by 19.5%.

  20. Modulation of HIV-1 Gag NC/p1 cleavage efficiency affects protease inhibitor resistance and viral replicative capacity

    Czech Academy of Sciences Publication Activity Database

    Maarseveen van, N. M.; Andersson, Dan; Lepšík, Martin; Fun, A.; Schipper, P. J.; Jong de, D.; Boucher, Ch. A. B.; Nijhuis, M.

    2012-01-01

    Roč. 9, č. 29 (2012), s. 1-7 ISSN 1742-4690 EU Projects: European Commission(XE) 37693 - HIV PI RESISTANCE Grant - others:Dutch AIDS Fund(XE) 2006028; (NWO) VIDI(XE) 91796349 Institutional research plan: CEZ:AV0Z40550506 Keywords : HIV -1 * protease * Gag * resistance * cleavage Subject RIV: CE - Biochemistry Impact factor: 5.657, year: 2012

  1. An Efficient Microarray-Based Genotyping Platform for the Identification of Drug-Resistance Mutations in Majority and Minority Subpopulations of HIV-1 Quasispecies.

    Directory of Open Access Journals (Sweden)

    Verónica Martín

    Full Text Available The response of human immunodeficiency virus type 1 (HIV-1 quasispecies to antiretroviral therapy is influenced by the ensemble of mutants that composes the evolving population. Low-abundance subpopulations within HIV-1 quasispecies may determine the viral response to the administered drug combinations. However, routine sequencing assays available to clinical laboratories do not recognize HIV-1 minority variants representing less than 25% of the population. Although several alternative and more sensitive genotyping techniques have been developed, including next-generation sequencing (NGS methods, they are usually very time consuming, expensive and require highly trained personnel, thus becoming unrealistic approaches in daily clinical practice. Here we describe the development and testing of a HIV-1 genotyping DNA microarray that detects and quantifies, in majority and minority viral subpopulations, relevant mutations and amino acid insertions in 42 codons of the pol gene associated with drug- and multidrug-resistance to protease (PR and reverse transcriptase (RT inhibitors. A customized bioinformatics protocol has been implemented to analyze the microarray hybridization data by including a new normalization procedure and a stepwise filtering algorithm, which resulted in the highly accurate (96.33% detection of positive/negative signals. This microarray has been tested with 57 subtype B HIV-1 clinical samples extracted from multi-treated patients, showing an overall identification of 95.53% and 89.24% of the queried PR and RT codons, respectively, and enough sensitivity to detect minority subpopulations representing as low as 5-10% of the total quasispecies. The developed genotyping platform represents an efficient diagnostic and prognostic tool useful to personalize antiviral treatments in clinical practice.

  2. HIV Controllers Exhibit Enhanced Frequencies of Major Histocompatibility Complex Class II Tetramer+Gag-Specific CD4+T Cells in Chronic Clade C HIV-1 Infection.

    Science.gov (United States)

    Laher, Faatima; Ranasinghe, Srinika; Porichis, Filippos; Mewalal, Nikoshia; Pretorius, Karyn; Ismail, Nasreen; Buus, Søren; Stryhn, Anette; Carrington, Mary; Walker, Bruce D; Ndung'u, Thumbi; Ndhlovu, Zaza M

    2017-04-01

    Immune control of viral infections is heavily dependent on helper CD4 + T cell function. However, the understanding of the contribution of HIV-specific CD4 + T cell responses to immune protection against HIV-1, particularly in clade C infection, remains incomplete. Recently, major histocompatibility complex (MHC) class II tetramers have emerged as a powerful tool for interrogating antigen-specific CD4 + T cells without relying on effector functions. Here, we defined the MHC class II alleles for immunodominant Gag CD4 + T cell epitopes in clade C virus infection, constructed MHC class II tetramers, and then used these to define the magnitude, function, and relation to the viral load of HIV-specific CD4 + T cell responses in a cohort of untreated HIV clade C-infected persons. We observed significantly higher frequencies of MHC class II tetramer-positive CD4 + T cells in HIV controllers than progressors ( P = 0.0001), and these expanded Gag-specific CD4 + T cells in HIV controllers showed higher levels of expression of the cytolytic proteins granzymes A and B. Importantly, targeting of the immunodominant Gag41 peptide in the context of HLA class II DRB1*1101 was associated with HIV control ( r = -0.5, P = 0.02). These data identify an association between HIV-specific CD4 + T cell targeting of immunodominant Gag epitopes and immune control, particularly the contribution of a single class II MHC-peptide complex to the immune response against HIV-1 infection. Furthermore, these results highlight the advantage of the use of class II tetramers in evaluating HIV-specific CD4 + T cell responses in natural infections. IMPORTANCE Increasing evidence suggests that virus-specific CD4 + T cells contribute to the immune-mediated control of clade B HIV-1 infection, yet there remains a relative paucity of data regarding the role of HIV-specific CD4 + T cells in shaping adaptive immune responses in individuals infected with clade C, which is responsible for the majority of HIV

  3. The Chinese Life-Steps Program: A Cultural Adaptation of a Cognitive-Behavioral Intervention to Enhance HIV Medication Adherence

    Science.gov (United States)

    Shiu, Cheng-Shi; Chen, Wei-Ti; Simoni, Jane; Fredriksen-Goldsen, Karen; Zhang, Fujie; Zhou, Hongxin

    2013-01-01

    China is considered to be the new frontier of the global AIDS pandemic. Although effective treatment for HIV is becoming widely available in China, adherence to treatment remains a challenge. This study aimed to adapt an intervention promoting HIV-medication adherence--favorably evaluated in the West--for Chinese HIV-positive patients. The…

  4. Efficient perovskite/organic integrated solar cells with extended photoresponse to 930 nm and enhanced near-infrared external quantum efficiency of over 50.

    Science.gov (United States)

    Guo, Qiang; Liu, Hao; Shi, Zhenzhen; Wang, Fuzhi; Zhou, Erjun; Bian, Xingming; Zhang, Bing; Alsaedi, Ahmed; Hayat, Tasawar; Tan, Zhan'ao

    2018-02-15

    Enhancing the light-harvesting activity is an effective way to improve the power conversion efficiency of solar cells. Although rapid enhancement in the PCE up to a value of 22.1% has been achieved for perovskite solar cells, only part of the sunlight, i.e., with wavelengths below 800-850 nm is utilized due to the limited bandgap of the perovskite materials, resulting in most of the near infrared light being wasted. To broaden the photoresponse of perovskite solar cells, we demonstrate an efficient perovskite/organic integrated solar cell containing both CH 3 NH 3 PbI 3 perovskite and PBDTTT-E-T:IEICO organic photoactive layers. By integrating a low band gap PBDTTT-E-T:IEICO active layer on a perovskite layer, the maximum wavelength for light harvesting of the ISC increased to 930 nm, sharply increasing the utilization of near infrared radiation. In addition, the external quantum efficiency of the integrated device exceeded 50% in the near infrared range. The MAPbI 3 /PBDTTT-E-T:IEICO ISCs show an enhanced short-circuit current density of over 24 mA cm -2 , which is the highest existing value among perovskite/organic integrated solar cells and much higher than the traditional MAPbI 3 based perovskite solar cells. The results reveal that a perovskite/organic integrated structure is a promising strategy to extend and enhance sunlight utilization for perovskite solar cells.

  5. Assessment of the range of the HIV-1 infectivity enhancing effect of individual human semen specimen and the range of inhibition by EGCG

    Directory of Open Access Journals (Sweden)

    Hartjen Philip

    2012-01-01

    Full Text Available Abstract Recently, it has been shown that human ejaculate enhances human immunodeficiency virus 1 (HIV-1 infectivity. Enhancement of infectivity is conceived to be mediated by amyloid filaments from peptides that are proteolytically released from prostatic acid phosphatase (PAP, termed Semen-derived Enhancer of Virus Infection (SEVI. The aim of this study was to test the range of HIV-1 infectivity enhancing properties of a large number of individual semen samples (n = 47 in a TZM-bl reporter cell HIV infection system. We find that semen overall increased infectivity to 156% of the control experiment without semen, albeit with great inter- and intraindividual variability (range -53%-363%. Using transmission electron microscopy, we provide evidence for SEVI fibrils in fresh human semen for the first time. Moreover, we confirm that the infectivity enhancing property can be inhibited by the major green tea ingredient epigallocatechin-3-gallate (EGCG at non-toxic concentrations. The median inhibition of infection by treatment with 0.4 mM EGCG was 70.6% (p

  6. Increasing the efficiency of organic solar cells by photonic and electrostatic-field enhancements

    Energy Technology Data Exchange (ETDEWEB)

    Nalwa, Kanwar [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    recombination of charge carriers. Thus it becomes imperative to understand the effect of processing conditions such as spin coating speed and drying rate on defect density and hence induced carrier recombination mechanism. In this study, It is shown that slow growth (longer drying time) of the active-layer leads to reduction of sub-bandgap traps by an order of magnitude as compared to fast grown active-layer. By coupling the experimental results with simulations, it is demonstrated that at one sun condition, slow grown device has bimolecular recombination as the major loss mechanism while in the fast grown device with high trap density, the trap assisted recombination dominates. It has been estimated that non-radiative recombination accounts nearly 50% of efficiency loss in modern OPVs. Generally, an external bias (electric field) is required to collect all the photogenerated charges and thus prevent their recombination. The motivation is to induce additional electric field in otherwise low mobility conjugated polymer based active layer by incorporating ferroelectric dipoles. This is expected to facilitate singlet exciton dissociation in polymer matrix and impede charge transfer exciton (CTE) recombination at polymer:fullerene interface. For the first time, it is shown that the addition of ferroelectric dipoles to modern bulk heterojunction (BHJ) can significantly improve exciton dissociation, resulting in a ~50% enhancement of overall solar cell efficiency. The devices also exhibit the unique ferroelectric-photovoltaic effect with polarization-controlled power conversion efficiency.

  7. Lack of enhancing effect of human anti-human immunodeficiency virus type 1 (HIV-1) antibody on HIV-1 infection of human blood monocytes and peritoneal macrophages.

    OpenAIRE

    Shadduck, P P; Weinberg, J B; Haney, A. F.; Bartlett, J. A.; Langlois, A J; Bolognesi, D P; Matthews, T J

    1991-01-01

    The influence of human anti-human immunodeficiency virus type 1 (HIV-1) antibody on HIV-1 infection of freshly isolated normal human peritoneal macrophages and blood monocytes was examined. Each of 14 HIV antibody-positive human serum samples was found to block the infection of four virus isolates (human T-cell lymphotropic virus type IIIBa-L [HTLV-IIIBa-L], HTLV-IIIB, D.U. 6587-7, and D.U. 7887-8) at serum dilutions ranging from 10(-1) to 10(-2). Three of these isolates (HTLV-IIIBa-L, D.U. 6...

  8. Histological Evidence of Chronic Mycoplasma genitalium���Induced Cervicitis in HIV-Infected Women: A Retrospective Cohort Study

    OpenAIRE

    Dehon, Patricia M.; Hagensee, Michael E; Sutton, Kimberly J.; Oddo, Hope E.; Nelson, Nia; McGowin, Chris L.

    2016-01-01

    Background.���Mycoplasma genitalium is an emerging sexually transmitted pathogen implicated in inflammatory syndromes of the female reproductive tract. The objective of this study was to investigate human immunodeficiency virus (HIV)���infected women for an association between M. genitalium and cervicitis, a putative mechanism for enhanced HIV transmission efficiency to an uninfected partner.

  9. No evidence for selection of HIV-1 with enhanced gag-protease or Nef function among breakthrough infections in the CAPRISA 004 tenofovir microbicide trial.

    Directory of Open Access Journals (Sweden)

    Denis R Chopera

    Full Text Available Use of antiretroviral-based microbicides for HIV-1 prophylaxis could introduce a transmission barrier that inadvertently facilitates the selection of fitter viral variants among incident infections. To investigate this, we assessed the in vitro function of gag-protease and nef sequences from participants who acquired HIV-1 during the CAPRISA 004 1% tenofovir microbicide gel trial.We isolated the earliest available gag-protease and nef gene sequences from 83 individuals and examined their in vitro function using recombinant viral replication capacity assays and surface protein downregulation assays, respectively. No major phylogenetic clustering and no significant differences in gag-protease or nef function were observed in participants who received tenofovir gel versus placebo gel prophylaxis.Results indicate that the partial protective effects of 1% tenofovir gel use in the CAPRISA 004 trial were not offset by selection of transmitted/early HIV-1 variants with enhanced Gag-Protease or Nef fitness.

  10. Removal of viable bioaerosol particles with a low-efficiency HVAC filter enhanced by continuous emission of unipolar air ions.

    Science.gov (United States)

    Huang, R; Agranovski, I; Pyankov, O; Grinshpun, S

    2008-04-01

    Continuous emission of unipolar ions has been shown to improve the performance of respirators and stationary filters challenged with non-biological particles. In this study, we investigated the ion-induced enhancement effect while challenging a low-efficiency heating, ventilation and air-conditioning (HVAC) filter with viable bacterial cells, bacterial and fungal spores, and viruses. The aerosol concentration was measured in real time. Samples were also collected with a bioaerosol sampler for viable microbial analysis. The removal efficiency of the filter was determined, respectively, with and without an ion emitter. The ionization was found to significantly enhance the filter efficiency in removing viable biological particles from the airflow. For example, when challenged with viable bacteria, the filter efficiency increased as much as four- to fivefold. For viable fungal spores, the ion-induced enhancement improved the efficiency by a factor of approximately 2. When testing with virus-carrying liquid droplets, the original removal efficiency provided by the filter was rather low: 9.09 +/- 4.84%. While the ion emission increased collection about fourfold, the efficiency did not reach 75-100% observed with bacteria and fungi. These findings, together with our previously published results for non-biological particles, demonstrate the feasibility of a new approach for reducing aerosol particles in HVAC systems used for indoor air quality control. Recirculated air in HVAC systems used for indoor air quality control in buildings often contains considerable number of viable bioaerosol particles because of limited efficiency of the filters installed in these systems. In the present study, we investigated - using aerosolized bacterial cells, bacterial and fungal spores, and virus-carrying particles - a novel idea of enhancing the performance of a low-efficiency HVAC filter utilizing continuous emission of unipolar ions in the filter vicinity. The findings described in

  11. A compensatory mutation provides resistance to disparate HIV fusion inhibitor peptides and enhances membrane fusion.

    Directory of Open Access Journals (Sweden)

    Matthew P Wood

    Full Text Available Fusion inhibitors are a class of antiretroviral drugs used to prevent entry of HIV into host cells. Many of the fusion inhibitors being developed, including the drug enfuvirtide, are peptides designed to competitively inhibit the viral fusion protein gp41. With the emergence of drug resistance, there is an increased need for effective and unique alternatives within this class of antivirals. One such alternative is a class of cyclic, cationic, antimicrobial peptides known as θ-defensins, which are produced by many non-human primates and exhibit broad-spectrum antiviral and antibacterial activity. Currently, the θ-defensin analog RC-101 is being developed as a microbicide due to its specific antiviral activity, lack of toxicity to cells and tissues, and safety in animals. Understanding potential RC-101 resistance, and how resistance to other fusion inhibitors affects RC-101 susceptibility, is critical for future development. In previous studies, we identified a mutant, R5-tropic virus that had evolved partial resistance to RC-101 during in vitro selection. Here, we report that a secondary mutation in gp41 was found to restore replicative fitness, membrane fusion, and the rate of viral entry, which were compromised by an initial mutation providing partial RC-101 resistance. Interestingly, we show that RC-101 is effective against two enfuvirtide-resistant mutants, demonstrating the clinical importance of RC-101 as a unique fusion inhibitor. These findings both expand our understanding of HIV drug-resistance to diverse peptide fusion inhibitors and emphasize the significance of compensatory gp41 mutations.

  12. Glucopyranosyl lipid A adjuvant significantly enhances HIV specific T and B cell responses elicited by a DNA-MVA-protein vaccine regimen.

    Directory of Open Access Journals (Sweden)

    Paul F McKay

    Full Text Available Using a unique vaccine antigen matched and single HIV Clade C approach we have assessed the immunogenicity of a DNA-poxvirus-protein strategy in mice and rabbits, administering MVA and protein immunizations either sequentially or simultaneously and in the presence of a novel TLR4 adjuvant, GLA-AF. Mice were vaccinated with combinations of HIV env/gag-pol-nef plasmid DNA followed by MVA-C (HIV env/gag-pol-nef with HIV CN54gp140 protein (+/-GLA-AF adjuvant and either co-administered in different muscles of the same animal with MVA-C or given sequentially at 3-week intervals. The DNA prime established a population of B cells that were able to mount a statistically significant anamnestic response to the boost vaccines. The greatest antigen-specific antibody response was observed in animals that received all vaccine components. Moreover, a high proportion of the total mucosal IgG (20 - 50% present in the vaginal vault of these vaccinated animals was vaccine antigen-specific. The potent elicitation of antigen-specific immune responses to this vaccine modality was also confirmed in rabbits. Importantly, co-administration of MVA-C with the GLA-AF adjuvanted HIV CN54gp140 protein significantly augmented the antigen-specific T cell responses to the Gag antigen, a transgene product expressed by the MVA-C vector in a separate quadriceps muscle. We have demonstrated that co-administration of MVA and GLA-AF adjuvanted HIV CN54gp140 protein was equally effective in the generation of humoral responses as a sequential vaccination modality thus shortening and simplifying the immunization schedule. In addition, a significant further benefit of the condensed vaccination regime was that T cell responses to proteins expressed by the MVA-C were potently enhanced, an effect that was likely due to enhanced immunostimulation in the presence of systemic GLA-AF.

  13. A Cross-Site Intervention in Chinese Rural Migrants Enhances HIV/AIDS Knowledge, Attitude and Behavior

    Directory of Open Access Journals (Sweden)

    Ning Li

    2014-04-01

    Full Text Available Background: With the influx of rural migrants into urban areas, the spread of HIV has increased significantly in Shaanxi Province (China. Migrant workers are at high risk of HIV infection due to social conditions and hardships (isolation, separation, marginalization, barriers to services, etc.. Objective: We explored the efficacy of a HIV/AIDS prevention and control program for rural migrants in Shaanxi Province, administered at both rural and urban sites. Methods: Guidance concerning HIV/AIDS prevention was given to the experimental group (266 migrants for 1 year by the center of disease control, community health agencies and family planning department. The intervention was conducted according to the HIV/AIDS Prevention Management Manual for Rural Migrants. A control group of migrants only received general population intervention. The impact of the intervention was evaluated by administering HIV/AIDS knowledge, attitudes and sexual behavior (KAB questionnaires after 6 and 12 months. Results: In the experimental group; 6 months of intervention achieved improvements in HIV/AIDS related knowledge. After 12 months; HIV/AIDS-related knowledge reached near maximal scores. Attitude and most behaviors scores were significantly improved. Moreover; the experimental group showed significant differences in HIV-AIDS knowledge; attitude and most behavior compared with the control group. Conclusions: The systematic long-term cross-site HIV/AIDS prevention in both rural and urban areas is a highly effective method to improve HIV/AIDS KAB among rural migrants.

  14. HIV-1 gp41-targeting fusion inhibitory peptides enhance the gp120-targeting protein-mediated inactivation of HIV-1 virions

    OpenAIRE

    Qi, Qianqian; Wang, Qian; Chen, Weizao; Du, Lanying; Dimitrov, Dimiter S; Lu, Lu; Jiang, Shibo

    2017-01-01

    Protein- or peptide-based viral inactivators are being developed as novel antiviral drugs with improved efficacy, pharmacokinetics and toxicity profiles because they actively inactivate cell-free human immunodeficiency virus type 1 (HIV-1) virions before attachment to host cells. By contrast, most clinically used antiviral drugs must penetrate host cells to inhibit viral replication. In this study, we pre-treated HIV-1 particles with a gp120-targeting bispecific multivalent protein, 2Dm2m or ...

  15. Envelope deglycosylation enhances antigenicity of HIV-1 gp41 epitopes for both broad neutralizing antibodies and their unmutated ancestor antibodies.

    Directory of Open Access Journals (Sweden)

    Ben-Jiang Ma

    2011-09-01

    Full Text Available The HIV-1 gp41 envelope (Env membrane proximal external region (MPER is an important vaccine target that in rare subjects can elicit neutralizing antibodies. One mechanism proposed for rarity of MPER neutralizing antibody generation is lack of reverted unmutated ancestor (putative naive B cell receptor antibody reactivity with HIV-1 envelope. We have studied the effect of partial deglycosylation under non-denaturing (native conditions on gp140 Env antigenicity for MPER neutralizing antibodies and their reverted unmutated ancestor antibodies. We found that native deglycosylation of clade B JRFL gp140 as well as group M consensus gp140 Env CON-S selectively increased the reactivity of Env with the broad neutralizing human mAbs, 2F5 and 4E10. Whereas fully glycosylated gp140 Env either did not bind (JRFL, or weakly bound (CON-S, 2F5 and 4E10 reverted unmutated ancestors, natively deglycosylated JRFL and CON-S gp140 Envs did bind well to these putative mimics of naive B cell receptors. These data predict that partially deglycoslated Env would bind better than fully glycosylated Env to gp41-specific naïve B cells with improved immunogenicity. In this regard, immunization of rhesus macaques demonstrated enhanced immunogenicity of the 2F5 MPER epitope on deglyosylated JRFL gp140 compared to glycosylated JRFL gp140. Thus, the lack of 2F5 and 4E10 reverted unmutated ancestor binding to gp140 Env may not always be due to lack of unmutated ancestor antibody reactivity with gp41 peptide epitopes, but rather, may be due to glycan interference of binding of unmutated ancestor antibodies of broad neutralizing mAb to Env gp41.

  16. Nano-architecture based photoelectrochemical water oxidation efficiency enhancement by CdS photoanodes

    Science.gov (United States)

    Pareek, Alka; Kim, Hyun Gyu; Paik, Pradip; Joardar, Joydip; Borse, Pramod H.

    2017-02-01

    In the present work, 2D nanostructuring has been utilized to impart an efficiency improvement to the hexagonal phase CdS films for the photoelectrochemical (PEC) cells those were deposited by spray pyrolysis technique. By controlling the aerosol droplet- size, population and impingement time during the spray pyrolysis deposition, various nano-features viz. randomly aligned nanorods, nanotubes and nanowires of CdS has been demonstrated for the first time. A growth mechanism has been proposed to predict the temporal evolution of the nanostructures. The prominent nanoscale structures show improved optical properties in the visible range of solar spectrum. The structural studies validate the morphological differences of nanostructures in terms of the texture coefficient analysis as well as 2D micro x-ray diffraction imaging. Electrochemical characterization is carried out to understand the effect of nanostructuring on the PEC performance of the CdS photoanodes in the sulphide (0.1 M Na2S  +  0.02 M Na2SO3) electrolyte at applied bias of 0.2 V (versus SCE). The evolution of morphology from randomly aligned rods to nanowire is responsible for improved photocurrent (3.5 times). CdS film morphology can be tuned to nanotubes, nano- rose buds and nanorod bunches even by doping Zn2+ ions in CdS lattice. Nano-structuring of doped CdS has shown enhanced performance of the photoanodes. The nanotubes structures yielded highest photocurrent density of 1.6 mA cm-2. Whereas modifying the 2D-nanostructured CdS film by simple MoO3 spray coating yields the photocurrent enhancement to 2.1 mA cm-2.

  17. Plasmon enhanced power conversion efficiency in inverted bulk heterojunction organic solar cell

    Science.gov (United States)

    Mohan, Minu; Ramkumar, S.; Namboothiry, Manoj A. G.

    2017-08-01

    P3HT:PCBM is one of the most studied polymer-fullerene system. However the reported power conversion efficiency (PCE) values falls within the range of 4% to 5%. The thin film architecture in OPVs exhibits low PCE compared to inorganic photovoltaic cells. This is mainly due to the low exciton diffusion length that limits the active layer thickness which in turn reduces the absorption of incident light. Several strategies are adapted in order to increase the absorption in the active layer without increasing the film thickness. Inclusion of metal nanoparticles into the polymer layer of bulk heterojunction (BHJ) solar cells is one of the promising methods. Incorporation of metal nanostructures increases the absorption of organic materials due to the high electromagnetic field strength in the vicinity of the excited surface plasmons. In this work, we used 60 nm Au plasmonic structures to improve the efficiency of organic solar cell. The prepared metal nano structures were characterized through scanning electron microscopy (SEM), and UV-Visible spectroscopy techniques. These prepared metallic nanoparticles can be incorporated either into the electron transport layer (ETL) or into the active P3HT:PC71BM layer. The effect of incorporation of plasmonic gold (Au) nanoparticle in the inverted bulk heterojunction organic photovoltaic cells (OPVs) of P3HT:PC71BM fabricated in ambient air condition is in progress. Initial studies shows an 8.5% enhancement in the PCE with the incorporation of Au nanoparticles under AM1.5G light of intensity 1 Sun.

  18. A saw-tooth plasma actuator for film cooling efficiency enhancement of a shaped hole

    Science.gov (United States)

    Li, Guozhan; Yu, Jianyang; Liu, Huaping; Chen, Fu; Song, Yanping

    2017-08-01

    This paper reports the large eddy simulations of the effects of a saw-tooth plasma actuator and the laidback fan-shaped hole on the film cooling flow characteristics, and the numerical results are compared with a corresponding standard configuration (cylindrical hole without the saw-tooth plasma actuator). For this numerical research, the saw-tooth plasma actuator is installed just downstream of the cooling hole and a phenomenological plasma model is employed to provide the 3D plasma force vectors. The results show that thanks to the downward force and the momentum injection effect of the saw-tooth plasma actuator, the cold jet comes closer to the wall surface and extends further downstream. The saw-tooth plasma actuator also induces a new pair of vortex which weakens the strength of the counter-rotating vortex pair (CRVP) and entrains the coolant towards the wall, and thus the diffusion of the cold jet in the crossflow is suppressed. Furthermore, the laidback fan-shaped hole reduces the vertical jet velocity causing the disappearance of downstream spiral separation node vortices, this compensates for the deficiency of the saw-tooth plasma actuator. Both effects of the laidback fan-shaped hole and the saw-tooth plasma actuator effectively control the development of the CRVP whose size and strength are smaller than those of the anti-counter rotating vortex pair in the far field, thus the centerline and the spanwise-averaged film cooling efficiency are enhanced. The average film cooling efficiency is the biggest in the Fan-Dc = 1 case, which is 80% bigger than that in the Fan-Dc = 0 case and 288% bigger than that in the Cyl-Dc = 0 case.

  19. Solution-processed photonic crystals to enhance the light outcoupling efficiency of organic light-emitting diodes.

    Science.gov (United States)

    Cho, Hwan-Hee; Park, Boik; Kim, Hyong-Jun; Jeon, Sohee; Jeong, Jun-Ho; Kim, Jang-Joo

    2010-07-20

    We report an effective solution process to fabricate planarized photonic crystal substrates to enhance the outcoupling efficiency of organic light-emitting diodes (OLEDs). The photonic crystal structure was fabricated using nanoimprint lithography using a UV-curable acrylate and was planarized by using a ZnO layer formed by the solgel process. The solgel process resulted in a smooth surface, and OLEDs have been successfully integrated on the planarized photonic crystal layer with a low leakage current. The resulting light outcoupling efficiency was enhanced by 38% compared with that of conventional OLEDs, which is well matched with a theoretical prediction.

  20. Enhanced Emission Efficiency of Size-Controlled InGaN/GaN Green Nanopillar Light-Emitting Diodes

    DEFF Research Database (Denmark)

    Ou, Yiyu; Iida, Daisuke; Fadil, Ahmed

    2016-01-01

    Nanopillar InGaN/GaN green light-emitting diode (LED) arrays were fabricated by self-assembled Au nanoparticles patterning and dry etching process. Structure size and density of the nanopillar arrays have been modified by varying the Au film thickness in the nanopatterning process. Fabricated....... Meanwhile light extraction efficiency can also be enhanced significantly due to the increased light scattering at nanopillar sidewall. Compared to the planar LED, the nanopillar LED demonstrates the greatest external quantum efficiency enhancement by a factor of 4.08. It is believed that this nanopillar...

  1. Efficient Techniques of Sparse Signal Analysis for Enhanced Recovery of Information in Biomedical Engineering and Geosciences

    KAUST Repository

    Sana, Furrukh

    2016-11-01

    Sparse signals are abundant among both natural and man-made signals. Sparsity implies that the signal essentially resides in a small dimensional subspace. The sparsity of the signal can be exploited to improve its recovery from limited and noisy observations. Traditional estimation algorithms generally lack the ability to take advantage of signal sparsity. This dissertation considers several problems in the areas of biomedical engineering and geosciences with the aim of enhancing the recovery of information by exploiting the underlying sparsity in the problem. The objective is to overcome the fundamental bottlenecks, both in terms of estimation accuracies and required computational resources. In the first part of dissertation, we present a high precision technique for the monitoring of human respiratory movements by exploiting the sparsity of wireless ultra-wideband signals. The proposed technique provides a novel methodology of overcoming the Nyquist sampling constraint and enables robust performance in the presence of noise and interferences. We also present a comprehensive framework for the important problem of extracting the fetal electrocardiogram (ECG) signals from abdominal ECG recordings of pregnant women. The multiple measurement vectors approach utilized for this purpose provides an efficient mechanism of exploiting the common structure of ECG signals, when represented in sparse transform domains, and allows leveraging information from multiple ECG electrodes under a joint estimation formulation. In the second part of dissertation, we adopt sparse signal processing principles for improved information recovery in large-scale subsurface reservoir characterization problems. We propose multiple new algorithms for sparse representation of the subsurface geological structures, incorporation of useful prior information in the estimation process, and for reducing computational complexities of the problem. The techniques presented here enable significantly

  2. Design, fabrication, and characterization of polymer based bulk heterojunction solar cells with enhanced efficiencies

    Science.gov (United States)

    Lu, Haiwei

    Polymer based bulk heterojunction (BHJ) solar cells offer promising technological advantages for actualization of low-cost and large-area fabrication on flexible substrates. To reach the envisaged market entry figure of 10% power conversion efficiency (PCE), it is crucial that more solar energy is utilized in the active layer, requiring both higher energy conversion efficiency and expansion of the absorption spectrum of the active layer to near infrared (NIR) region. The research introduced in this dissertation is an effort to increase PCE of solar cells from the aforementioned two directions. In the first method, carbon nanotubes (CNTs) were incorporated into polymer-fullerene BHJ solar cells to increase the hole-collection efficiency. Devices with CNT monolayer networks placed at different positions were fabricated, and the impact of CNTs on device performance was studied. It was demonstrated that CNTs placed on the hole-collection side of the device resulted in optimized performance, with PCE increased from 4% to 4.9%. To realize the controlled deposition of a uniform layer of CNTs on different positions, a mild plasma treatment of the active-layer was employed, and the influence of plasma treatment on device performance was also studied. In the second strategy, I developed an approach to expand the absorption spectrum to NIR region. In this case, hybrid polymer based BHJ solar cells composed of pyridine-capped PbS (PbS-py) quantum dots (QDs) and poly(3-hexylthiophene) (P3HT) were proposed. With pyridines as capping ligands, devices showed superior performance compared to with conventionally used oleate agents. PbS QDs with bandgaps of ˜1.13-1.38 eV offered the advantage of energetically favorable charge separation between P3HT and PbS QDs for photoexcitons in both visible and NIR regions. It was also found that thermal annealing leads to the removal of excess and interfacial pyridine ligands in polymer/QDs composites, and thus provides intimate electrical

  3. Development of Human Dendritic Cells and their Role in HIV Infection: Antiviral Immunity vs HIV Transmission

    Directory of Open Access Journals (Sweden)

    Yasuko eTsunetsugu-Yokota

    2013-07-01

    Full Text Available Although dendritc cells (DC represent a small cell population in the body, they have been recognized as professional antigen presenting cells and key players of both innate and acquired immunity. The recent expansion of basic knowledge concerning differentiation and function of various DC subsets will greatly help to understand the nature of protective immunity required in designing AIDS vaccines. However, HIV not only targets CD4+ T cells but also myeloid cells, including macrophages and DC. When HIV infects DC, its replication is highly restricted in DC. Nevertheless, even a low level of HIV production is sufficient to enhance HIV replication in activated CD4+ T cells, through antigen presentation activity by HIV-infected DC. Considering how antiviral immunity is initiated and memory response is maintained, such efficient DC-T cell transmission of HIV should play an important role in the disturbed immune responses associated with HIV infection. Recently, accessory proteins encoded by HIV have been shown to interact with various proteins in DC, and thereby affect DC-T cell transmission. In this review, we summarize the current understanding about DC biology and discuss what needs to be known in order to successfully manipulate DC for the development of an effective AIDS vaccine in the future.

  4. Designing the inner surface corrugations of hollow fibers to enhance CO2 absorption efficiency.

    Science.gov (United States)

    Fashandi, Hossein; Zarrebini, Mohammad; Ghodsi, Ali; Saghafi, Reza

    2016-08-15

    For the first time, a low cost strategy is introduced to enhance the efficiency of CO2 absorption using gas-liquid membrane contactors. This is implemented by designing the corrugations in the inner layer of poly(vinyl chloride) hollow fibers (PVC HFs) through changing the bore fluid composition. In fact, the number of corrugations in the HF inner layer is engineered via changing the phase separation time within the inner layer. Such that expedited phase separation leads to highly corrugated inner layer. In contrast, decelerated phase separation is responsible for reduced number of inner layer corrugations. Phase separation causes the initial polymer solution with low viscoelastic moduli to be transferred into polymer-rich domains with high viscoelastic moduli. These domains resist against stretching-induced radial forces toward the center of HF; therefore, the inner layer of HF buckles. Delayed phase separation defers formation of polymer-rich domains and hence, HF with less corrugated inner surface is expected. The phase separation within the HF inner layer is controlled through changing the rate of solvent/nonsolvent exchange. This is conducted by variation the solvent content in the bore fluid; as higher as solvent content, as slower as solvent/nonsolvent exchange. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Enhanced water use efficiency in global terrestrial ecosystems under increasing aerosol loadings

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiaoliang; Chen, Min; Liu, Yaling; Miralles, Diego G.; Wang, Faming

    2017-05-01

    Aerosols play a crucial role in the climate system, affecting incoming radiation and cloud formation. Based on a modelling framework that couples ecosystem processes with the atmospheric transfer of radiation, we analyze the effect of aerosols on surface incoming radiation, gross primary productivity (GPP), water losses from ecosystems through evapotranspiration (ET) and ecosystem water use efficiency (WUE, defined as GPP/ET) for 2003–2010 and validate them at global FLUXNET sites. The total diffuse radiation increases under relatively low or intermediate aerosol loadings, but decreases under more polluted conditions. We find that aerosol-induced changes in GPP depend on leaf area index, aerosol loading and cloudiness. Specifically, low and moderate aerosol loadings cause increases in GPP for all plant types, while heavy aerosol loadings result in enhancement (decrease) in GPP for dense (sparse) vegetation. On the other hand, ET is mainly negatively affected by aerosol loadings due to the reduction in total incoming radiation. Finally, WUE shows a consistent rise in all plant types under increasing aerosol loadings. Overall, the simulated daily WUE compares well with observations at 43 eddy-covariance tower sites (R2=0.84 and RMSE=0.01gC (kg H2O)-1) with better performance at forest sites. In addition to the increasing portions of diffuse light, the rise in WUE is also favored by the reduction in radiation- and heat-stress caused by the aerosols, especially for wet and hot climates.

  6. Enhanced THz emission efficiency of composition-tunable InGaAs nanowire arrays

    Science.gov (United States)

    BeleckaitÄ--, I.; Treu, J.; Morkötter, S.; Döblinger, M.; Xu, X.; Adomavičius, R.; Finley, J. J.; Koblmüller, G.; Krotkus, A.

    2017-05-01

    We report the terahertz (THz) emission properties of composition-tunable, intrinsically n-type InGaAs nanowire (NW) arrays using THz time-domain spectroscopy. By tuning the alloy composition of In1-xGaxAs NWs from pure InAs (x(Ga)=0) up to the intermediate composition (x(Ga)˜0.5), a substantially enhanced (>3-fold) THz emission efficiency is found, which is ascribed to a reduction in electron accumulation at the NW surface and respective electron scattering at donor-type surface defects. These findings are also confirmed by photoexcitation wavelength dependent measurements, while the THz emission characteristics are further found to be different from corresponding bulk-type planar InGaAs. In particular, NWs exhibit no distinct maxima in THz excitation spectra as caused by electron scattering to subsidiary conduction band valleys and commonly observed in the majority of bulk semiconductors. The wavelength-dependent emission spectra further reveal distinct signatures of modified intervalley scattering, revealing the underlying polytypism of intermixed wurtzite and zincblende phases in the investigated InGaAs NWs.

  7. Enhanced Laser-to-Electron Energy Conversion Efficiency using Micro-Plasma Waveguide (MPW) Targets

    Science.gov (United States)

    Nasir, Derek; Snyder, Joseph; Ji, Liang; George, Kevin; Willis, Christopher; Cochran, Ginevra; Zingale, Anthony; Daskalova, Rebecca; Schumacher, Doug; van Woerkom, Linn

    2017-10-01

    We present experiments from the Scarlet laser facility and 3D Particle in Cell (PIC) simulations detailing the improved hot electron spectrum of MPW targets over flat targets. We observe an increase in the electron cutoff energy by a factor of 3 and a 10x enhancement of the total signal of electrons above 5MeV. From PIC simulations, we see strong transverse electric fields extract electron bunches from the MPW walls with the laser period, which are then accelerated by the usual vxB force. In addition, quasi-static longitudinal electric fields arise and are observed to increase the acceleration length of electrons along the tube walls. In this way, the micro-engineered structures provide a geometry more conducive to efficient direct laser acceleration and offer a new dimension in target design. We present evidence that by varying the structure's geometry we can alter the laser plasma interactions with applications in high field science, laser based proton therapy and relativistic nonlinear optics. In particular, the relationship between the MPW tube and laser-electron dephasing length is examined. AFOSR #FA9550-14-1-0085; NNSA #DE-NA0003107; DOE #DE-SC0012333.

  8. ENHANCEMENT OF PHENOL REMOVAL EFFICIENCY IN DORA REFINERY WASTEWATER TREATMENT PLANT

    Directory of Open Access Journals (Sweden)

    Salah F. Sharif

    2013-05-01

    Full Text Available Because the sanctions imposed on Iraq by the United Nations, programmed maintenance and wearing parts replacement has not been performed according to schedules in DORA Refinery Wastewater Unit, which resulted in higher phenol content and BOD5 in effluents disposed to river. The investigations showed that two main reasons were behind this problem: Firstly, increased emissions of hydrocarbons in the complexity of refinery equipment and Secondly, the decreased efficiency of the aerators in the biological. During the last few months, phenol average concentration in the effluent, after biological treatment was found to be between 0.06-0.13 mg/L, while COD was exceeding 110 mg/L after treatment in the same period. Considerable enhancement, has been indicated recently, after the following performances: First: Recycling wastewater from some heat exchangers, and the segregation of low and high strength of wastewaters, Second: Minimizing emissions of hydrocarbons from fluid catalytic cracking and steam cracking, Third: Replacement of driving motors of the aerators in the biological treatment unit. After replacement of these units, a significant decrease in phenol concentration was obtained in purified water (0.03-0.05 mg/L and COD of 60 mg/L before the tertiary treatment. It is concluded that a better quality of effluents has been obtained after a series of emissions control and wastewater treatment unit equipment maintenance performances.

  9. Microwave Enhanced Direct Cracking of Hydrocarbon Feedstock for Energy Efficient Production of Ethylene and Propylene.

    Energy Technology Data Exchange (ETDEWEB)

    Shulman, Holly; Fall, Morgana; Wagner, Eric; Bowlin, Ricardo

    2012-02-13

    This project demonstrated microwave cracking of ethane with good product conversion and ethylene selectivity, with a short residence time ({approx}0.001 sec). The laboratory scale equipment was designed and built, along with concept designs for larger scale implementation. The system was operated below atmospheric pressures, in the range of 15-55 torr, with argon as a carrier gas. The measured products included hydrogen, methane, acetylene, and ethylene. The results followed similar trends to those predicted by the modeling software SPYRO{reg_sign}, with the exception that the microwave appeared to produce slightly lower amounts of ethylene and methane, although enhanced analytical analysis should reduce the difference. Continued testing will be required to verify these results and quantify the energy consumption of microwave vs. conventional. The microwave cracking process is an attractive option due to the possibility of selectively heating the reaction volume rather than the reactor walls, which may allow novel reactor designs that result in more efficient production of ethylene. Supplemental studies are needed to continue the laboratory testing and refine processing parameters.

  10. Trial for Enhancing Technical Writing Skills to Improve Training Efficiency in Writing Technical Papers

    Science.gov (United States)

    Uneda, Michio; Ishikawa, Ken-Ichi

    One of the important undertakings of student in laboratory education practiced in higher educational institutions, such as universities, is the development of technical communication skills based on training in technical writing for preparing not only bachelor‧s and master‧s theses but also papers to be submitted to society journals. However, technical writing is difficult for students who are not trained in writing papers, and it might become a burden for the teaching staff. Considering this situation, we have examined methods that may enhance the technical writing skills of students and also improve the training efficiency of the teaching staff. Specifically, the methods include distributing checklists to students, providing as few corrections as possible using underlines and adding comments when correcting students‧ writings, and instructing students to exchange their writings to check each other‧s work. In this paper, we summarize and analyze the effects of practicing the above methods on the basis of the answers to a questionnaire provided by students.

  11. Enhancing physical function in HIV-infected older adults: A randomized controlled clinical trial.

    Science.gov (United States)

    Shah, Krupa N; Majeed, Zahraa; Yoruk, Yilmaz B; Yang, Hongmei; Hilton, Tiffany N; McMahon, James M; Hall, William J; Walck, Donna; Luque, Amneris E; Ryan, Richard M

    2016-06-01

    HIV-infected older adults (HOA) are at risk of functional decline. Interventions promoting physical activity that can attenuate functional decline and are easily translated into the HOA community are of high priority. We conducted a randomized, controlled clinical trial to evaluate whether a physical activity counseling intervention based on self-determination theory (SDT) improves physical function, autonomous motivation, depression and the quality of life (QOL) in HOA. In total, 67 community-dwelling HOA with mild-to-moderate functional limitations were randomized to 1 of 2 groups: a physical activity counseling group or the usual care control group. We used SDT to guide the development of the experimental intervention. Outcome measures that were collected at baseline and final study visits included a battery of physical function tests, levels of physical activity, autonomous motivation, depression, and QOL. The study participants were similar in their demographic and clinical characteristics in both the treatment and control groups. Overall physical performance, gait speed, measures of endurance and strength, and levels of physical activity improved in the treatment group compared to the control group (p autonomous regulation such as identified regulation, and measures of depression and QOL improved significantly in the treatment group compared with the control group (p autonomous motivation, depression, and QOL in HOA with functional limitations. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  12. Efficiency Enhancement Mechanism for Poly(3, 4-ethylenedioxythiophene):Poly(styrenesulfonate)/Silicon Nanowires Hybrid Solar Cells Using Alkali Treatment

    Science.gov (United States)

    Jiang, Yurong; Gong, Xiu; Qin, Ruiping; Liu, Hairui; Xia, Congxin; Ma, Heng

    2016-05-01

    The efficiency enhancement mechanism of the alkali-treated Si nanowire (SiNW) solar cells is discussed and analyzed in detail, which is important to control the useful photovoltaic process. All the results demonstrate that the photovoltaic performance enhancement of alkali-treated SiNW device steps from the formation of the good core-shell heterojunction, which consequently enhances the junction area, promotes fast separating and transporting of electron and hole pairs, and reduces the carrier surface combination. It also indicates that alkali treatment for SiNWs is a promising processing as an economical method for the formation of good core-shell SiNW/polymer heterojunction.

  13. Efficiency Enhancement Mechanism for Poly(3, 4-ethylenedioxythiophene):Poly(styrenesulfonate)/Silicon Nanowires Hybrid Solar Cells Using Alkali Treatment.

    Science.gov (United States)

    Jiang, Yurong; Gong, Xiu; Qin, Ruiping; Liu, Hairui; Xia, Congxin; Ma, Heng

    2016-12-01

    The efficiency enhancement mechanism of the alkali-treated Si nanowire (SiNW) solar cells is discussed and analyzed in detail, which is important to control the useful photovoltaic process. All the results demonstrate that the photovoltaic performance enhancement of alkali-treated SiNW device steps from the formation of the good core-shell heterojunction, which consequently enhances the junction area, promotes fast separating and transporting of electron and hole pairs, and reduces the carrier surface combination. It also indicates that alkali treatment for SiNWs is a promising processing as an economical method for the formation of good core-shell SiNW/polymer heterojunction.

  14. Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems

    Science.gov (United States)

    Xiong, Jin Wen; Wan, Man Pun

    2017-01-01

    The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency. PMID:28594862

  15. Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV systems.

    Directory of Open Access Journals (Sweden)

    Bing Feng Ng

    Full Text Available The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

  16. Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems.

    Science.gov (United States)

    Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

    2017-01-01

    The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

  17. Packet size optimization for goodput and energy efficiency enhancement in slotted IEEE 802.15.4 networks

    NARCIS (Netherlands)

    Zhang, Y.; Shu, F.

    2009-01-01

    To address system goodput and energy efficiency enhancement, this paper studies packet size optimization for IEEE 802.15.4 networks. Taking into account of the CSMA-CA contention, protocol overhead, and channel condition, new analytical models are proposed to calculate the goodput and the energy

  18. [Evaluation of efficiency of the sonotherapy in enhancement of venous leg ulcer healing in patients after surgical and conservative treatment].

    Science.gov (United States)

    Franek, Andrzej; Brzezińska-Wcisło, Ligia; Cierpka, Lech; Chmielewska, Daria; Dolibog, Patrycja; Błaszczak, Edward; Taradaj, Jakub

    2008-07-01

    The aim of the study was to evaluate the application of sonotherapy in enhancement venous leg ulcer healing after conservative and surgical therapy. The 60 patients were included into the study. The 30 patients, who agreed on operation and were accepted by medical team to the surgical treatment, had been included to A and B group. The others, 30 patients were treated conservatively, and had been included to C and D group. The patients in group A and C were additionally treated in use of sonotherapy. The evaluated factors were to estimate the sonotherapy promotes total wound closure and causes any changes of the relative surface, longest and widest dimensions, and volume of tissue defect, pus and granulation degree. After study in all groups, we noticed a therapeutic effect. Treatment was more efficient in patients after surgical operation than in patients after conservative methods. Beneficial effects of sonotherapy in conservative enhancement of ulcer healing were observed. No impact of sonotherapy after surgical procedure was noticed. The sonotherapy is useful and efficient method only in enhancement of venous leg ulcer healing after conservative treatment. In surgically treated patients is not efficient method, because there is no accelerating impact on wound healing. As well conducted surgical operation more efficiently enhance a healing process than conservative pharmacological procedures.

  19. Large Stokes shift downshifting Eu(III) films as efficiency enhancing UV blocking layers for dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, M.; Ahmed, H.; Doran, J.; Norton, B. [Dublin Energy Laboratory, Dublin Institute of Technology (Ireland); Bosch-Jimenez, P.; Della Pirriera, M.; Torralba-Calleja, E.; Gutierrez Tauste, D.; Aubouy, L. [Leitat Technological Center, Terrassa (Spain); Daren, S.; Solomon-Tsvetkov, F. [Daren Laboratories, Ness-Ziona (Israel); Galindo, S.; Voz, C.; Puigdollers, J. [Universitat Politecnica Catalunya, Barcelona (Spain)

    2015-01-01

    Large Stokes shift downshifting organolanthanide complex, Eu(tta){sub 3}phen, is examined for inclusion in polymeric layers to replace the UV blocking layer in dye sensitized solar cell (DSSC) technology. The UV blocking layer increases stability but power conversion efficiency decreases as incident UV photons are not converted into photocurrent. Eu(tta){sub 3}phen doped polymeric film are prepared and attached to DSSC devices following optimized thickness and concentration from a ray-trace numerical model for the specific DSSC. External quantum efficiency is significantly increased in the UV spectral region compared to DSSCs utilizing a passive, non-luminescent, UV-BL. High Eu(tta){sub 3}phen film transparency in the visible range minimizes DSSC EQE losses at visible wavelengths. Short-circuit current (I{sub sc}) enhancement due to downshifting is demonstrated (∝1%) in small-scale DSSC prototypes, where the specific geometry limits the photon collection efficiency and overall enhancement. Model predictions indicate that 2%-3% Isc enhancement is realizable in flexible single DSSC compared to, non-luminescent, UV-BL. Added to this, in outdoor conditions taking into account diffuse light, the increment in I{sub sc} can increase 50% more. Although photostability of the blended LSS-DS polymer films is not sufficient to be useful for medium-long term outdoor PV applications, the results demonstrate that significant efficiency enhancement can be realized. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Enhanced external quantum efficiency in GaN-based vertical-type light-emitting diodes by localized surface plasmons

    Science.gov (United States)

    Yao, Yung-Chi; Hwang, Jung-Min; Yang, Zu-Po; Haung, Jing-Yu; Lin, Chia-Ching; Shen, Wei-Chen; Chou, Chun-Yang; Wang, Mei-Tan; Huang, Chun-Ying; Chen, Ching-Yu; Tsai, Meng-Tsan; Lin, Tzu-Neng; Shen, Ji-Lin; Lee, Ya-Ju

    2016-01-01

    Enhancement of the external quantum efficiency of a GaN-based vertical-type light emitting diode (VLED) through the coupling of localized surface plasmon (LSP) resonance with the wave-guided mode light is studied. To achieve this experimentally, Ag nanoparticles (NPs), as the LSP resonant source, are drop-casted on the most top layer of waveguide channel, which is composed of hydrothermally synthesized ZnO nanorods capped on the top of GaN-based VLED. Enhanced light-output power and external quantum efficiency are observed, and the amount of enhancement remains steady with the increase of the injected currents. To understand the observations theoretically, the absorption spectra and the electric field distributions of the VLED with and without Ag NPs decorated on ZnO NRs are determined using the finite-difference time-domain (FDTD) method. The results prove that the observation of enhancement of the external quantum efficiency can be attributed to the creation of an extra escape channel for trapped light due to the coupling of the LSP with wave-guided mode light, by which the energy of wave-guided mode light can be transferred to the efficient light scattering center of the LSP. PMID:26935648

  1. Infection with HIV and HCV enhances the release of fatty acid synthase into circulation: evidence for a novel indicator of viral infection

    Directory of Open Access Journals (Sweden)

    Aragonès Gerard

    2010-08-01

    Full Text Available Abstract Background Fatty acid synthase (FASN is an enzyme synthesized by the liver and plays an important role in lipogenesis. The present study aimed to investigate whether serum FASN concentration may provide a direct link between HIV and/or HCV viral infections and lipid metabolic disorders commonly observed in HIV/HCV-infected patients. Methods We evaluated serum FASN concentration in 191 consecutive HIV-infected patients in the absence or presence of HCV co-infection. For comparison, 102 uninfected controls were included. Metabolic and inflammatory phenotype was also compared with respect to the presence of HCV co-infection. Results Serum FASN concentration was significantly higher in HIV-infected patients than in healthy participants and HCV co-infected patients showed higher levels than those without co-infection. Levels were also affected by treatment regimen, but marginally influenced by virological variables. Insulin concentration was the sole variable among metabolic parameters that demonstrated a significant correlation with serum FASN concentrations. Serum alanine aminotransferase (ALT values correlated significantly with serum FASN concentration and provided the best discrimination with respect to the presence or absence of HCV co-infection. In multivariate analysis, only ALT, monocyte chemoattractant protein-1 (MCP-1 and the presence of antiretroviral treatment regimen significantly contributed to explain serum FASN concentration in HIV/HCV co-infected patients. Conclusion Serum FASN concentration is significantly increased in HIV-infected individuals. The release of FASN into the circulation is further enhanced in patients who are co-infected with HCV. Subsequent studies should explore the usefulness of this indicator to monitor the effect of viral infections on disease progression and survival.

  2. Infection with HIV and HCV enhances the release of fatty acid synthase into circulation: evidence for a novel indicator of viral infection.

    Science.gov (United States)

    Aragonès, Gerard; Alonso-Villaverde, Carlos; Oliveras-Ferraros, Cristina; Beltrán-Debón, Raúl; Rull, Anna; Rodríguez-Sanabria, Fernando; Camps, Jordi; Martín, Alejandro Vázquez; Menéndez, Javier A; Joven, Jorge

    2010-08-13

    Fatty acid synthase (FASN) is an enzyme synthesized by the liver and plays an important role in lipogenesis. The present study aimed to investigate whether serum FASN concentration may provide a direct link between HIV and/or HCV viral infections and lipid metabolic disorders commonly observed in HIV/HCV-infected patients. We evaluated serum FASN concentration in 191 consecutive HIV-infected patients in the absence or presence of HCV co-infection. For comparison, 102 uninfected controls were included. Metabolic and inflammatory phenotype was also compared with respect to the presence of HCV co-infection. Serum FASN concentration was significantly higher in HIV-infected patients than in healthy participants and HCV co-infected patients showed higher levels than those without co-infection. Levels were also affected by treatment regimen, but marginally influenced by virological variables. Insulin concentration was the sole variable among metabolic parameters that demonstrated a significant correlation with serum FASN concentrations. Serum alanine aminotransferase (ALT) values correlated significantly with serum FASN concentration and provided the best discrimination with respect to the presence or absence of HCV co-infection. In multivariate analysis, only ALT, monocyte chemoattractant protein-1 (MCP-1) and the presence of antiretroviral treatment regimen significantly contributed to explain serum FASN concentration in HIV/HCV co-infected patients. Serum FASN concentration is significantly increased in HIV-infected individuals. The release of FASN into the circulation is further enhanced in patients who are co-infected with HCV. Subsequent studies should explore the usefulness of this indicator to monitor the effect of viral infections on disease progression and survival.

  3. Fusion proteins of HIV-1 envelope glycoprotein gp120 with CD4-induced antibodies showed enhanced binding to CD4 and CD4 binding site antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Weizao, E-mail: chenw3@mail.nih.gov [Protein Interactions Group, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States); Feng, Yang [Protein Interactions Group, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States); Wang, Yanping [Protein Interactions Group, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States); The Basic Research Program, Science Applications International Corporation-Frederick, Inc., National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States); Zhu, Zhongyu; Dimitrov, Dimiter S. [Protein Interactions Group, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States)

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer Some recombinant HIV-1 gp120s do not preserve their conformations on gp140s. Black-Right-Pointing-Pointer We hypothesize that CD4i antibodies could induce conformational changes in gp120. Black-Right-Pointing-Pointer CD4i antibodies enhance binding of CD4 and CD4bs antibodies to gp120. Black-Right-Pointing-Pointer CD4i antibody-gp120 fusion proteins could have potential as vaccine immunogens. -- Abstract: Development of successful AIDS vaccine immunogens continues to be a major challenge. One of the mechanisms by which HIV-1 evades antibody-mediated neutralizing responses is the remarkable conformational flexibility of its envelope glycoprotein (Env) gp120. Some recombinant gp120s do not preserve their conformations on gp140s and functional viral spikes, and exhibit decreased recognition by CD4 and neutralizing antibodies. CD4 binding induces conformational changes in gp120 leading to exposure of the coreceptor-binding site (CoRbs). In this study, we test our hypothesis that CD4-induced (CD4i) antibodies, which target the CoRbs, could also induce conformational changes in gp120 leading to better exposed conserved neutralizing antibody epitopes including the CD4-binding site (CD4bs). We found that a mixture of CD4i antibodies with gp120 only weakly enhanced CD4 binding. However, such interactions in single-chain fusion proteins resulted in gp120 conformations which bound to CD4 and CD4bs antibodies better than the original or mutagenically stabilized gp120s. Moreover, the two molecules in the fusion proteins synergized with each other in neutralizing HIV-1. Therefore, fusion proteins of gp120 with CD4i antibodies could have potential as components of HIV-1 vaccines and inhibitors of HIV-1 entry, and could be used as reagents to explore the conformational flexibility of gp120 and mechanisms of entry and immune evasion.

  4. Myxoma virus oncolytic efficiency can be enhanced through chemical or genetic disruption of the actin cytoskeleton.

    Directory of Open Access Journals (Sweden)

    Chad R Irwin

    Full Text Available Myxoma virus (MYXV is one of many animal viruses that exhibit oncolytic properties in transformed human cells. Compared to orthopoxviruses like vaccinia (VACV, MYXV spreads inefficiently, which could compromise its use in treating tumors and their associated metastases. The VACV F11 protein promotes virus exit and rapid spread by inhibiting Rho signalling, which results in a disruption of cortical actin. We have previously shown that although MYXV lacks an F11 homolog, the F11L gene can be introduced into MYXV promoting the spread of this Leporipoxvirus in natural host cells. Here we show that the F11-encoding (F11L(+ MYXV strain replicates to higher levels in a number of human cancer cells. We also show that F11L(+ MYXV induces better tumor control and prolonged survival of mice bearing MDA-MB-231 cancer cells. Furthermore, we show that this virus also spreads more efficiently from the site of growth in one injected tumor, to a second untreated tumor. While we focused mostly on the use of a modified MYXV we were able to show that the effects of F11 on MYXV growth in cancer cells could be mimicked through the use of pharmacological inhibition or siRNA-mediated silencing of key regulators of cortical actin (RhoA, RhoC, mDia1, or LIMK2. These data suggest that it may be possible to increase the oncolytic efficacy of wild-type MYXV using chemical inhibitors of RhoA/C or their downstream targets. Furthermore, since all viruses must overcome barriers to exit posed by structures like cortical actin, these findings suggest that the oncolytic activity of other viruses may be enhanced through similar strategies.

  5. Myxoma Virus Oncolytic Efficiency Can Be Enhanced Through Chemical or Genetic Disruption of the Actin Cytoskeleton

    Science.gov (United States)

    Irwin, Chad R.; Favis, Nicole A.; Agopsowicz, Kate C.; Hitt, Mary M.; Evans, David H.

    2013-01-01

    Myxoma virus (MYXV) is one of many animal viruses that exhibit oncolytic properties in transformed human cells. Compared to orthopoxviruses like vaccinia (VACV), MYXV spreads inefficiently, which could compromise its use in treating tumors and their associated metastases. The VACV F11 protein promotes virus exit and rapid spread by inhibiting Rho signalling, which results in a disruption of cortical actin. We have previously shown that although MYXV lacks an F11 homolog, the F11L gene can be introduced into MYXV promoting the spread of this Leporipoxvirus in natural host cells. Here we show that the F11-encoding (F11L+) MYXV strain replicates to higher levels in a number of human cancer cells. We also show that F11L+ MYXV induces better tumor control and prolonged survival of mice bearing MDA-MB-231 cancer cells. Furthermore, we show that this virus also spreads more efficiently from the site of growth in one injected tumor, to a second untreated tumor. While we focused mostly on the use of a modified MYXV we were able to show that the effects of F11 on MYXV growth in cancer cells could be mimicked through the use of pharmacological inhibition or siRNA-mediated silencing of key regulators of cortical actin (RhoA, RhoC, mDia1, or LIMK2). These data suggest that it may be possible to increase the oncolytic efficacy of wild-type MYXV using chemical inhibitors of RhoA/C or their downstream targets. Furthermore, since all viruses must overcome barriers to exit posed by structures like cortical actin, these findings suggest that the oncolytic activity of other viruses may be enhanced through similar strategies. PMID:24391902

  6. Enhanced photo-transfection efficiency of mammalian cells on graphene coated substrates

    Science.gov (United States)

    Mthunzi, Patience; He, Kuang; Ngcobo, Sandile; Warner, Jamie W.

    2014-03-01

    Literature reports graphene, an atomic-thick sheet of carbon atoms as one of the promising biocompatible scaffolds that promotes cellular proliferation in human mesenchymal stem cells. On the other hand, different mammalian cell lines including the induced pluripotent stem cells exhibited an accelerated proliferation rate when cultured on graphene or graphene oxide coated substrates. These findings provide strong motivation to explore the full capability of graphene in further pluripotent stem cell research activities as there exists an urgent requirement to preserve their therapeutic potential. This therefore calls for non-invasive procedures for handling stem cells in-vitro. For example, resent literature has shown successful laser light driven transfection in both multipotent and pluripotent stem cells. In order to explore the non-invasive nature of optical transfection alongside biocompatible qualities of graphene, in this work we investigated the impact of optically transfecting mouse embryonic stem (mES) cells plated on graphene coated sample chambers. Using Chinese Hamster Ovary cells (CHO-K1), we further studied the influence of graphene on cell viability as well as cell cytotoxicity through assessing changes in levels of mitochondrial adenosine triphosphate (ATP) activity and the release of cytosolic lactate dehydrogenase (LHD) respectively. Our results showed that compared to those treated on plain glass, CHO-K1 cells optically treated while plated on graphene coated substrates exhibited a higher production of ATP and a milder release of LDH. In addition there was enhanced photo-transfection efficiency in both CHO-K1 and mES cells irradiated on graphene sample chambers.

  7. Reverse lyotropic liquid crystals from europium nitrate and P123 with enhanced luminescence efficiency.

    Science.gov (United States)

    Yi, Sijing; Li, Qintang; Liu, Hongguo; Chen, Xiao

    2014-10-02

    Fabrication of lyotropic aggregates containing the lanthanide ions is becoming a preferable way to prepare novel functional materials. Here, the lyotropic liquid crystals (LLCs) of reverse hexagonal, reverse bicontinuous cubic, and lamellar phases have been constructed in sequence directly from the mixtures of Eu(NO3)3·6H2O and Pluronic P123 amphiphilc block copolymer with increasing the salt proportion. Their phase types and structural characteristics were analyzed using polarized optical microscopy (POM) and small-angle X-ray scattering (SAXS) measurements. The driving forces of reverse LLC phase formation were investigated using Fourier-transformed infrared spectroscopy (FTIR) and rheological measurements. The hydrated europium salt was found to act not only as a solvent here, but also as the bridge to form hydrogen bonding between coordinated water molecules and PEO blocks, which played a key role in the reverse LLCs formation. Compared to those in aqueous solutions and solid state, the enhanced luminescence quantum yields and prolonged excited state lifetimes were observed in two europium containing reverse mesophases. The luminescence quenching effect of lanthanide ions was efficiently suppressed, probably due to the substitution of coordinated water molecules by oxyethyl groups of P123 and ordered phase structures of LLCs, where the coordinated europium ions were confined and isolated by PEO blocks. The optimum luminescence performance was then found to exist in the reverse hexagonal phase. The obtained results on such lanthanide-induced reverse LLCs should be referable for designing new luminescent soft materials construction to expand their application fields.

  8. Myxoma virus oncolytic efficiency can be enhanced through chemical or genetic disruption of the actin cytoskeleton.

    Science.gov (United States)

    Irwin, Chad R; Favis, Nicole A; Agopsowicz, Kate C; Hitt, Mary M; Evans, David H

    2013-01-01

    Myxoma virus (MYXV) is one of many animal viruses that exhibit oncolytic properties in transformed human cells. Compared to orthopoxviruses like vaccinia (VACV), MYXV spreads inefficiently, which could compromise its use in treating tumors and their associated metastases. The VACV F11 protein promotes virus exit and rapid spread by inhibiting Rho signalling, which results in a disruption of cortical actin. We have previously shown that although MYXV lacks an F11 homolog, the F11L gene can be introduced into MYXV promoting the spread of this Leporipoxvirus in natural host cells. Here we show that the F11-encoding (F11L(+)) MYXV strain replicates to higher levels in a number of human cancer cells. We also show that F11L(+) MYXV induces better tumor control and prolonged survival of mice bearing MDA-MB-231 cancer cells. Furthermore, we show that this virus also spreads more efficiently from the site of growth in one injected tumor, to a second untreated tumor. While we focused mostly on the use of a modified MYXV we were able to show that the effects of F11 on MYXV growth in cancer cells could be mimicked through the use of pharmacological inhibition or siRNA-mediated silencing of key regulators of cortical actin (RhoA, RhoC, mDia1, or LIMK2). These data suggest that it may be possible to increase the oncolytic efficacy of wild-type MYXV using chemical inhibitors of RhoA/C or their downstream targets. Furthermore, since all viruses must overcome barriers to exit posed by structures like cortical actin, these findings suggest that the oncolytic activity of other viruses may be enhanced through similar strategies.

  9. Sulfated polysaccharide, curdlan sulfate, efficiently prevents entry/fusion and restricts antibody-dependent enhancement of dengue virus infection in vitro: a possible candidate for clinical application.

    Directory of Open Access Journals (Sweden)

    Koji Ichiyama

    Full Text Available Curdlan sulfate (CRDS, a sulfated 1→3-β-D glucan, previously shown to be a potent HIV entry inhibitor, is characterized in this study as a potent inhibitor of the Dengue virus (DENV. CRDS was identified by in silico blind docking studies to exhibit binding potential to the envelope (E protein of the DENV. CRDS was shown to inhibit the DENV replication very efficiently in different cells in vitro. Minimal effective concentration of CRDS was as low as 0.1 µg/mL in LLC-MK2 cells, and toxicity was observed only at concentrations over 10 mg/mL. CRDS can also inhibit DENV-1, 3, and 4 efficiently. CRDS did not inhibit the replication of DENV subgenomic replicon. Time of addition experiments demonstrated that the compound not only inhibited viral infection at the host cell binding step, but also at an early post-attachment step of entry (membrane fusion. The direct binding of CRDS to DENV was suggested by an evident reduction in the viral titers after interaction of the virus with CRDS following an ultrafiltration device separation, as well as after virus adsorption to an alkyl CRDS-coated membrane filter. The electron microscopic features also showed that CRDS interacted directly with the viral envelope, and caused changes to the viral surface. CRDS also potently inhibited DENV infection in DC-SIGN expressing cells as well as the antibody-dependent enhancement of DENV-2 infection. Based on these data, a probable binding model of CRDS to DENV E protein was constructed by a flexible receptor and ligand docking study. The binding site of CRDS was predicted to be at the interface between domains II and III of E protein dimer, which is unique to this compound, and is apparently different from the β-OG binding site. Since CRDS has already been tested in humans without serious side effects, its clinical application can be considered.

  10. Sulfated polysaccharide, curdlan sulfate, efficiently prevents entry/fusion and restricts antibody-dependent enhancement of dengue virus infection in vitro: a possible candidate for clinical application.

    Science.gov (United States)

    Ichiyama, Koji; Gopala Reddy, Sindhoora Bhargavi; Zhang, Li Feng; Chin, Wei Xin; Muschin, Tegshi; Heinig, Lars; Suzuki, Youichi; Nanjundappa, Haraprasad; Yoshinaka, Yoshiyuki; Ryo, Akihide; Nomura, Nobuo; Ooi, Eng Eong; Vasudevan, Subhash G; Yoshida, Takashi; Yamamoto, Naoki

    2013-01-01

    Curdlan sulfate (CRDS), a sulfated 1→3-β-D glucan, previously shown to be a potent HIV entry inhibitor, is characterized in this study as a potent inhibitor of the Dengue virus (DENV). CRDS was identified by in silico blind docking studies to exhibit binding potential to the envelope (E) protein of the DENV. CRDS was shown to inhibit the DENV replication very efficiently in different cells in vitro. Minimal effective concentration of CRDS was as low as 0.1 µg/mL in LLC-MK2 cells, and toxicity was observed only at concentrations over 10 mg/mL. CRDS can also inhibit DENV-1, 3, and 4 efficiently. CRDS did not inhibit the replication of DENV subgenomic replicon. Time of addition experiments demonstrated that the compound not only inhibited viral infection at the host cell binding step, but also at an early post-attachment step of entry (membrane fusion). The direct binding of CRDS to DENV was suggested by an evident reduction in the viral titers after interaction of the virus with CRDS following an ultrafiltration device separation, as well as after virus adsorption to an alkyl CRDS-coated membrane filter. The electron microscopic features also showed that CRDS interacted directly with the viral envelope, and caused changes to the viral surface. CRDS also potently inhibited DENV infection in DC-SIGN expressing cells as well as the antibody-dependent enhancement of DENV-2 infection. Based on these data, a probable binding model of CRDS to DENV E protein was constructed by a flexible receptor and ligand docking study. The binding site of CRDS was predicted to be at the interface between domains II and III of E protein dimer, which is unique to this compound, and is apparently different from the β-OG binding site. Since CRDS has already been tested in humans without serious side effects, its clinical application can be considered.

  11. The effects of enhanced ultraviolet-B radiation and soil drought on water use efficiency of spring wheat.

    Science.gov (United States)

    Zhao, Honglin; Zhao, Zhinguang; An, Lizhe; Chen, Tuo; Wang, Xunling; Feng, Huyuan

    2009-01-09

    The effect of enhanced ultraviolet-B radiation (280-315 nm) and water stress on water consumption, instantaneous water use efficiency (WUEi), season-long water use efficiency (WUEs) and leaf stable carbon isotope composition (delta13C) of three spring wheat cultivars (Triticum aestivum L.) was investigated under field conditions. The relationship between WUEi and WUEs with delta13C was analyzed. Compared with the control, enhanced UV-B or water stress alone or in combination led to lower water use, and soil drought had a stronger influence on water use than supplementary UV-B irradiance. Soil drought increased the instantaneous water use efficiency (WUEi) and UV-B radiation decreased it significantly in comparison to the control. The combination of UV-B and water stress resulted in increased/reduced or no changed WUEi, different with change. Season-long water use efficiency (WUEs) showed the same trend as observed with WUEi under the conditions of UV-B radiation and water stress, except that no significant difference between control and drought in cv. Heshangtou. WUEs under the combined conditions of UV-B and water stress, was clearly increased in every cultivar. Enhanced UV-B radiation and the combination with drought led to negative foliar stable carbon isotope composition (delta13C) and drought alone resulted in a positive value for delta13C. The relationship between foliar stable carbon isotope composition and instantaneous water use efficiency was not significant. Nevertheless, a positive correlation with delta13C against season-long water use efficiency was observed. The results indicated that delta13C can be a useable parameter for selecting a crop genotype having higher water use efficiency.

  12. Immunogenetic influences on acquisition of HIV-1 infection: Consensus findings from two African cohorts point to an enhancer element in IL19 (1q32.2)

    Science.gov (United States)

    Li, Xuelin; Zhang, Kui; Pajewski, Nicholas M.; Brill, Ilene; Prentice, Heather A.; Shrestha, Sadeep; Kilembe, William; Karita, Etiene; Allen, Susan; Hunter, Eric; Kaslow, Richard A.; Tang, Jianming

    2015-01-01

    Numerous reports have suggested that immunogenetic factors may influence HIV-1 acquisition, yet replicated findings that translate between study cohorts remain elusive. Our work aimed to test several hypotheses about genetic variants within the IL10-IL24 gene cluster that encodes interleukin (IL)-10, IL-19, IL-20, and IL-24. In aggregated data from 515 Rwandans and 762 Zambians with up to 12 years of follow-up, 190 single nucleotide polymorphisms (SNPs) passed quality control procedures. When HIV-1-exposed seronegative subjects (n = 486) were compared with newly seroconverted individuals (n = 313) and seroprevalent subjects (n = 478) who were already infected at enrollment, rs12407485 (G>A) in IL19 showed a robust association signal in adjusted logistic regression models (odds ratio = 0.64, P = 1.7 × 10−4, and q = 0.033). Sensitivity analyses demonstrated that (i) results from both cohorts and subgroups within each cohort were highly consistent; (ii) verification of HIV-1 infection status after enrollment was critical; and (iii) supporting evidence was readily obtained from Cox proportional hazards models. Data from public databases indicate that rs12407485 is part of an enhancer element for three transcription factors. Overall, these findings suggest that molecular features at the IL19 locus may modestly alter the establishment of HIV-1 infection. PMID:25633979

  13. Enhanced Emission Performance and Fuel Efficiency for HD Methane Engines. Literature Study. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Broman, R.; Staalhammar, P.; Erlandsson, L.

    2010-05-15

    to change the combustion system from the Diesel-cycle to the Otto-cycle or to use the Diesel Dual Fuel (DDF) cycle which used a Diesel-like cycle. The Otto-cycle (spark ignited, SI) is the most common option when rebuilding a diesel engine to operate on methane. The Diesel dual fuelcycle can however offer some benefits since it uses Diesel injection for ignition of the methane/air mixture 'like a liquid' spark plug. Additionally, DDF systems can either use the original Diesel injectors together with injection of methane into the air intake, allowing use of methane and/or diesel for more flexibility, or employ a specially designed gas/Diesel injector, incorporating only a small range of Diesel injection which disable operating the engine on 100 % Diesel, but allows for more Diesel substitution by methane over the full operating range of the engine. The fuel used in methane fuelled engines is biomethane, compressed natural gas (CNG), liquefied natural gas (LNG) or liquefied biomethane (LBM). LNG/LBM is the preferred fuel for long haul trucks since it has significantly higher energy density implying smaller, but different gas cylinders on-board the vehicle. For vehicles operated in a local area, compressed methane gas might be the most suitable alternative. Other combinations of methane fuels could also be used as fuel within the transportation sector such as blends of fuels from fossil and renewable origin and hydrogen enriched natural gas, hythane (HCNG). A recent interest for Diesel dual fuel concepts has now appeared among stakeholders as an alternative or a complement to the conventional methane fuelled HD vehicles, underlined by the fact that differences in the actual mode of operation of vehicles will enhance advantages with various engine concepts. Compared to a SI methane fuelled engine a DDF concept could end up with better fuel efficiency using current engine technology. However, the potential for substitution of diesel with methane would be lower

  14. Efficiency of a second-generation HIV-1 protease inhibitor studied by molecular dynamics and absolute binding free energy calculations

    Czech Academy of Sciences Publication Activity Database

    Lepšík, Martin; Kříž, Z.; Havlas, Zdeněk

    2004-01-01

    Roč. 57, - (2004), s. 279-293 ISSN 0887-3585 R&D Projects: GA MŠk LN00A032; GA MŠk LN00A016; GA ČR GA203/00/0828 Institutional research plan: CEZ:AV0Z4055905 Keywords : HIV * inhibitor * resistance Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.429, year: 2004

  15. Expanding the generation and use of economic and financial data to improve HIV program planning and efficiency: a global perspective.

    Science.gov (United States)

    Holmes, Charles B; Atun, Rifat; Avila, Carlos; Blandford, John M

    2011-08-01

    Cost information is needed at multiple levels of health care systems to inform the public health response to HIV. To date, most attention has been paid to identifying the cost drivers of providing antiretroviral treatment, and these data have driven interventions that have been successful in reducing drug and human resource costs. The need for further cost information, especially for less well-studied areas such as HIV prevention, is particularly acute given global budget constraints and ongoing efforts to extract the greatest possible value from money spent on the response. Cost information can be collected from multiple perspectives and levels of the health care system (site, program, and national levels), and it is critical to choose the appropriate methodology in order to generate the appropriate information for decision-making. Organizations such as United States President's Emergency Plan for AIDS Relief, the Global Fund to Fight AIDS, Tuberculosis, and Malaria, and other organizations are working together to bridge the divide between the fields of economics and HIV program implementation by accelerating the collection of cost data and building further local demand and capacity for their use.

  16. An efficient approach to reliability-based design optimization within the enhanced sequential optimization and reliability assessment framework

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hong Zhong; Zhang, Xudong; Meng, De Biao; Wang, Zhonglai; Liu, Yu [University of Electronic Science and Technology of China, Chengdu (China)

    2013-06-15

    Reliability based design optimization (RBDO) has been widely implemented in engineering practices for high safety and reliability. It is an important challenge to improve computational efficiency. Sequential optimization and reliability assessment (SORA) has made great efforts to improve computational efficiency by decoupling a RBDO problem into sequential deterministic optimization and reliability analysis as a single-loop method. In this paper, in order to further improve computational efficiency and extend the application of the current SORA method, an enhanced SORA (ESORA) is proposed by considering constant and varying variances of random design variables while keeping the sequential framework. Some mathematical examples and an engineering case are given to illustrate the proposed method and validate the efficiency.

  17. Enhanced selectivity in mixed matrix membranes for CO2 capture through efficient dispersion of amine-functionalized MOF nanoparticles

    Science.gov (United States)

    Ghalei, Behnam; Sakurai, Kento; Kinoshita, Yosuke; Wakimoto, Kazuki; Isfahani, Ali Pournaghshband; Song, Qilei; Doitomi, Kazuki; Furukawa, Shuhei; Hirao, Hajime; Kusuda, Hiromu; Kitagawa, Susumu; Sivaniah, Easan

    2017-07-01

    Mixed matrix membranes (MMMs) for gas separation applications have enhanced selectivity when compared with the pure polymer matrix, but are commonly reported with low intrinsic permeability, which has major cost implications for implementation of membrane technologies in large-scale carbon capture projects. High-permeability polymers rarely generate sufficient selectivity for energy-efficient CO2 capture. Here we report substantial selectivity enhancements within high-permeability polymers as a result of the efficient dispersion of amine-functionalized, nanosized metal-organic framework (MOF) additives. The enhancement effects under optimal mixing conditions occur with minimal loss in overall permeability. Nanosizing of the MOF enhances its dispersion within the polymer matrix to minimize non-selective microvoid formation around the particles. Amination of such MOFs increases their interaction with thepolymer matrix, resulting in a measured rigidification and enhanced selectivity of the overall composite. The optimal MOF MMM performance was verified in three different polymer systems, and also over pressure and temperature ranges suitable for carbon capture.

  18. Enhancement of the photovoltaic conversion efficiency of copper phthalocyanine thin film devices by incorporation of metal clusters

    Energy Technology Data Exchange (ETDEWEB)

    Stenzel, O.; Stendal, A.; Voigtsberger, K.; Von Borczyskowski, C. [Technical University of Chemnitz-Zwickau, Institute of Physics, Subdept. of Optical Spectroscopy and Molecular Physics, Chemnitz (Germany)

    1995-07-30

    ITO-copperphthalocyanine-indium sandwich structures have been prepared by thermal evaporation in high vacuum. Different types of metal nanoclusters have been incorporated at the ITO-copperphthalocyanine interface. Significant differences in the photovoltaic conversion efficiency of the sandwich samples have been established as a function of the excitation wavelength. Copper clusters have been found to increase the conversion efficiency by a factor of nearly three for solar illumination. The observed effects are discussed assuming resonant light absorption in the metal clusters as the responsible physical mechanism for enhancement

  19. Efficient Removal of Co2+ from Aqueous Solution by 3-Aminopropyltriethoxysilane Functionalized Montmorillonite with Enhanced Adsorption Capacity

    OpenAIRE

    Zhujian Huang; Pingxiao Wu; Beini Gong; Yaping Dai; Pen-Chi Chiang; Xiaolin Lai; Guangwei Yu

    2016-01-01

    To achieve a satisfactory removal efficiency of heavy metal ions from wastewater, silane-functionalized montmorillonite with abundant ligand-binding sites (-NH2) was synthesized as an efficient adsorbent. Ca-montmorillonite (Ca-Mt) was functionalized with 3-aminopropyl triethoxysilane (APTES) to obtain the APTES-Mt products (APTES1.0CEC-Mt, APTES2.0CEC-Mt, APTES3.0CEC-Mt, APTES4.0CEC-Mt) with enhanced adsorption capacity for Co2+. The physico-chemical properties of the synthesized adsorbents ...

  20. Enhanced Efficiency of Polymer Light-Emitting Diodes by Dispersing Dehydrated Nanotube Titanic Acid in the Hole-buffer Layer

    Science.gov (United States)

    Qian, L.; Xu, Z.; Teng, F.; Duan, X.-X.; Jin, Z.-S.; Du, Z.-L.; Li, F.-S.; Zheng, M.-J.; Wang, Y.-S.

    2007-06-01

    Efficiency of polymer light-emitting diodes (PLEDs) with poly(2-methoxy-5-(2-ethyl hexyloxy)- p-phenylene vinylene) (MEH-PPV) as an emitting layer was improved if a dehydrated nanotubed titanic acid (DNTA) doped hole-buffer layer polyethylene dioxythiophene (PEDOT) was used. Photoluminescence (PL) and Raman spectra indicated a stronger interaction between DNTA and sulfur atom in thiophene of PEDOT, which suppresses the chemical interaction between vinylene of MEH-PPV and thiophene of PEDOT. The interaction decreases the defect states in an interface region to result in enhancement in device efficiency, even though the hole transporting ability of PEDOT was decreased.

  1. Enhanced Efficiency of Polymer Light-Emitting Diodes by Dispersing Dehydrated Nanotube Titanic Acid in the Hole-buffer Layer

    Energy Technology Data Exchange (ETDEWEB)

    Qian, L., E-mail: qian_lei@126.com; Xu, Z.; Teng, F.; Duan, X.-X. [Beijing Jiaotong University, Institute of Optoelectronic Technology (China); Jin, Z.-S.; Du, Z.-L. [Henan University, Key Laboratory on special functional materials (China); Li, F.-S.; Zheng, M.-J. [State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, Department of Physics (China); Wang, Y.-S. [Beijing Jiaotong University, Institute of Optoelectronic Technology (China)

    2007-06-15

    Efficiency of polymer light-emitting diodes (PLEDs) with poly(2-methoxy-5-(2-ethyl hexyloxy)-p-phenylene vinylene) (MEH-PPV) as an emitting layer was improved if a dehydrated nanotubed titanic acid (DNTA) doped hole-buffer layer polyethylene dioxythiophene (PEDOT) was used. Photoluminescence (PL) and Raman spectra indicated a stronger interaction between DNTA and sulfur atom in thiophene of PEDOT, which suppresses the chemical interaction between vinylene of MEH-PPV and thiophene of PEDOT. The interaction decreases the defect states in an interface region to result in enhancement in device efficiency, even though the hole transporting ability of PEDOT was decreased.

  2. Evaluation and comparison of insulation efficiency of three enhancer-blocking insulators in plants

    Science.gov (United States)

    Enhancer-promoter interactions potentially compromise the precise engineering of gene function and agronomically important traits in crops, which demands the adoption of strong, effective enhancer-blocking insulators to block such communication in a transgene construct. In this study, we evaluated ...

  3. Social support seeking and self-efficacy-building strategies in enhancing the emotional well-being of informal HIV/AIDS caregivers in Ibadan, Oyo state, Nigeria.

    Science.gov (United States)

    Okeke, Bernedette Okwuchukwu

    2016-01-01

    This study examined the relative efficacy of social support seeking (SSS) and self-efficacy building (SEB) in the management of emotional well-being of caregivers of people suffering from HIV/AIDS. It was based at the United States President's Emergency Plan for AIDS Relief (PEPFAR) center in the University College Hospital, Ibadan, Oyo state, being the first and the largest teaching hospital in Nigeria. A 3 × 2 factorial design consisting of treatment and a control group was used. The columns have two levels of gender being male and female caregivers. One-hundred and sixty-five (165) caregivers who were taking care of people that are suffering from HIV/AIDS were purposively selected and randomly assigned to the treatment groups and control. The treatment was carried out for a period of eight weeks. Two null hypotheses were tested, both at .05 levels of significance. Data were collected with the use of standardized intruments rating scale; social support scale, general self-efficacy scale and emotional well-being scale. ANCOVA was used to establish significant treatment effects with the pretest as covariate. Even though SSS and SEB were both found to be effective in enhancing the emotional well-being of informal caregivers in this study when compared to the controls, SSS was significantly more effective than SEB in achieving this goal. Since the HIV/AIDS patients cannot be adequately cared for in the hospital settings due to severe shortages of material, personnel and time, serious efforts should be made by the three levels of the health care system viz: the primary, secondary and tertiary health care systems, to encourage the employment of the psychological management of caregivers of people suffering from HIV/AIDS. Also, the psychologists, clinical psychologists and the significant others should be encouraged to employ this psychological management in the care of HIV/AIDS informal caregivers.

  4. Towards a More Energy Efficient Future: Applying indicators to enhance energy policy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    Improving energy efficiency is a shared policy goal of many governments around the world. The benefits of more efficient use of energy are well known. Not only does it reduce energy costs and investments in energy infrastructure, it also lowers fossil fuel dependency and CO2 emissions, while at the same time increasing competitiveness and improving consumer welfare. Yet many questions remain unanswered. What are the latest trends in global energy use and CO2 emissions? How do factors such as demography, economic structure, income, lifestyle and climate affect these trends? Where are the greatest potentials to further improve energy efficiency, and which data are required to support energy efficiency policy development? This publication answers these questions using the latest insights from the IEA energy indicators work. The goal is to show policy makers how in-depth indicators can be used to track the progress in efficiency and identify new opportunities for improvements.

  5. Efficient enhancement of below-threshold harmonic generation by laser-driven excited states of Cs atom

    Science.gov (United States)

    Guo, Qiao-Ling; Li, Peng-Cheng; Zhou, Xiao-Xin; Chu, Shih-I.

    2018-03-01

    We propose an efficient method for the enhancement of below-threshold harmonic generation (BTHG) by mid-infrared laser-driven excited states of a Cs atom. The BTHG is calculated by solving three-dimensional time-dependent Schrödinger equation accurately and efficiently using the time-dependent generalized pseudospectral method. We adopt an excited state as the initial state of a Cs atom. As a result, the BTHG is significantly enhanced by two orders of magnitude compared with the case of the initial ground state. Furthermore, we find that a single vacuum-ultraviolet pulse can be generated by mid-infrared laser-driven excited states by superposing several below-threshold harmonics of a Cs atom. Our finding suggests that the generation of below-threshold harmonics by laser-driven excited states of an atom can provide a powerful methodology for the production of intense vacuum-ultraviolet pulses.

  6. Heterogeneous integration of InGaAs nanowires on the rear surface of Si solar cells for efficiency enhancement.

    Science.gov (United States)

    Shin, Jae Cheol; Mohseni, Parsian K; Yu, Ki Jun; Tomasulo, Stephanie; Montgomery, Kyle H; Lee, Minjoo L; Rogers, John A; Li, Xiuling

    2012-12-21

    We demonstrate energy-conversion-efficiency (η) enhancement of silicon (Si) solar cells by the heterogeneous integration of an In(x)Ga(1-x)As nanowire (NW) array on the rear surface. The NWs are grown via a catalyst-free, self-assembled method on Si(111) substrates using metalorganic chemical vapor deposition (MOCVD). Heavily p-doped In(x)Ga(1-x)As (x ≈ 0.7) NW arrays are utilized as not only back-reflectors but also low bandgap rear-point-contacts of the Si solar cells. External quantum efficiency of the hybrid In(x)Ga(1-x)As NW-Si solar cell is increased over the entire solar response wavelength range; and η is enhanced by 36% in comparison to Si solar cells processed under the same condition without the NWs.

  7. Resonant quantum efficiency enhancement of midwave infrared nBn photodetectors using one-dimensional plasmonic gratings

    Energy Technology Data Exchange (ETDEWEB)

    Nolde, Jill A., E-mail: jill.nolde@nrl.navy.mil; Kim, Chul Soo; Jackson, Eric M.; Ellis, Chase T.; Abell, Joshua; Glembocki, Orest J.; Canedy, Chadwick L.; Tischler, Joseph G.; Vurgaftman, Igor; Meyer, Jerry R.; Aifer, Edward H. [Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, DC 20375 (United States); Kim, Mijin [Sotera Defense Solutions, Inc., 7230 Lee Deforest Dr. Suite 100, Columbia, Maryland 21046 (United States)

    2015-06-29

    We demonstrate up to 39% resonant enhancement of the quantum efficiency (QE) of a low dark current nBn midwave infrared photodetector with a 0.5 μm InAsSb absorber layer. The enhancement was achieved by using a 1D plasmonic grating to couple incident light into plasmon modes propagating in the plane of the device. The plasmonic grating is composed of stripes of deposited amorphous germanium overlaid with gold. Devices with and without gratings were processed side-by-side for comparison of their QEs and dark currents. The peak external QE for a grating device was 29% compared to 22% for a mirror device when the illumination was polarized perpendicularly to the grating lines. Additional experiments determined the grating coupling efficiency by measuring the reflectance of analogous gratings deposited on bare GaSb substrates.

  8. HIV TAT peptide modifies the distribution of DNA nanolipoparticles following convection-enhanced delivery.

    Science.gov (United States)

    MacKay, J Andrew; Li, Weijun; Huang, Zhaohua; Dy, Edward E; Huynh, Grace; Tihan, Tarik; Collins, Rodney; Deen, Dennis F; Szoka, Francis C

    2008-05-01

    We evaluated gene transfer using PEGylated bioresponsive nanolipid particles (NLPs) containing plasmid DNA administered by convection-enhanced delivery (CED) into orthotopically implanted U87-MG tumors in rat brain. We hypothesized that attachment of the human immunodeficiency virus trans-acting transcriptional activator peptide (TATp) to pH-sensitive, reduction-sensitive NLPs would increase gene transfer. TATp was attached either directly to a phospholipid (TATp-lipid) or via a 2-kd polyethylene glycol (PEG) to a lipid (TATp-PEG-lipid). Incorporation of 0.3 mol% TATp-PEG into pH-sensitive NLPs improved transfection 100,000-fold compared to NLPs in culture. In the brain or implanted tumors, the TATp-PEG restricted NLP convection to regions adjacent to the infusion catheter. Gene transfer in the brain from TATp-PEG NLPs, measured by green fluorescent protein (GFP) expression, was substantially greater than from NLPs adjacent to the catheter. Gene transfer using TATp-PEG NLPs, measured by luciferase expression, was 8-12-fold greater than from a 1,2-dioleoyl-3-trimethylammonium-propane/cholesterol cationic lipoplex but 13-27-fold less than from the NLPs. Brain luciferase expression was localized in perivascular macrophages. Thus a cationic ligand, such as the TATp-PEG-lipid, can dramatically increase gene expression in culture, in the normal brain, and in implanted tumors; however, restriction of NLP distribution to the vicinity of the infusion catheter reduces the absolute level of gene transfer.

  9. Enhancing the power conversion efficiency of dye-sensitized solar cells via molecular plasmon-like excitations.

    Science.gov (United States)

    Li, Jian-Hao; Gryn'ova, Ganna; Prlj, Antonio; Corminboeuf, Clémence

    2017-02-21

    We introduce a tactic for employing molecular plasmon-like excitations to enhance solar-to-electric power conversion efficiency of dye-sensitized solar cells. We offer general design principles of dimeric dyes, in which a strong plasmonic interaction between two π-conjugated moieties is promoted. The π-stacked conformations of these dimeric dyes result in a desirable broadened absorption and a longer absorption onset wavelength.

  10. Differential susceptibility of human thymic dendritic cell subsets to X4 and R5 HIV-1 infection.

    Science.gov (United States)

    Schmitt, Nathalie; Nugeyre, Marie-Thérèse; Scott-Algara, Daniel; Cumont, Marie-Christine; Barré-Sinoussi, Françoise; Pancino, Gianfranco; Israël, Nicole

    2006-02-28

    Human thymus can be infected by HIV-1 with potential consequences on immune regeneration and homeostasis. We previously showed that CD4 thymocytes preferentially replicate CXCR4 tropic (X4) HIV-1 dependently on interleukin (IL)-7. Here we addressed the susceptibility of thymic dendritic cells (DC) to HIV-1 infection. We investigated the replication ability of CXCR4 or CCR5 (R5) tropic HIV-1 in thymic micro-explants as well as in isolated thymic CD11clowCD14- DC, CD11chighCD14+ DC and plasmacytoid DC subsets. Thymic tissue was productively infected by both X4 and R5 viruses. However, X4 but not R5 HIV-1 replication was enhanced by IL-7 in thymic micro-explants, suggesting that R5 virus replication occurred in cells other than thymocytes. Indeed, we found that R5 HIV-1 replicated efficiently in DC isolated from thymic tissue. The replicative capacity of X4 and R5 viruses differed according to the different DC subsets. R5 but not X4 HIV-1 efficiently replicated in CD11chighCD14+ DC. In contrast, no HIV-1 replication was detected in CD11clowCD14- DC. Both X4 and R5 viruses efficiently replicated in plasmacytoid DC, which secreted interferon-alpha upon HIV-1 exposure. Productive HIV-1 infection also caused DC loss, consistent with different permissivity of each DC subset. Thymic DC sustain high levels of HIV-1 replication. DC might thus be the first target for R5 HIV-1 infection of thymus, acting as a Trojan horse for HIV-1 spread to thymocytes. Furthermore, DC death induced by HIV-1 infection may affect thymopoiesis.

  11. Enhanced energy conversion efficiency from high strength synthetic organic wastewater by sequential dark fermentative hydrogen production and algal lipid accumulation.

    Science.gov (United States)

    Ren, Hong-Yu; Liu, Bing-Feng; Kong, Fanying; Zhao, Lei; Xing, Defeng; Ren, Nan-Qi

    2014-04-01

    A two-stage process of sequential dark fermentative hydrogen production and microalgal cultivation was applied to enhance the energy conversion efficiency from high strength synthetic organic wastewater. Ethanol fermentation bacterium Ethanoligenens harbinense B49 was used as hydrogen producer, and the energy conversion efficiency and chemical oxygen demand (COD) removal efficiency reached 18.6% and 28.3% in dark fermentation. Acetate was the main soluble product in dark fermentative effluent, which was further utilized by microalga Scenedesmus sp. R-16. The final algal biomass concentration reached 1.98gL(-1), and the algal biomass was rich in lipid (40.9%) and low in protein (23.3%) and carbohydrate (11.9%). Compared with single dark fermentation stage, the energy conversion efficiency and COD removal efficiency of two-stage system remarkably increased 101% and 131%, respectively. This research provides a new approach for efficient energy production and wastewater treatment using a two-stage process combining dark fermentation and algal cultivation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Efficiency enhancement in a backside illuminated 1.12 μm pixel CMOS image sensor via parabolic color filters.

    Science.gov (United States)

    Lee, Jong-Kwon; Kim, Ahreum; Kang, Dong-Wan; Lee, Byung Yang

    2016-07-11

    The shrinkage of pixel size down to sub-2 μm in high-resolution CMOS image sensors (CISs) results in degraded efficiency and increased crosstalk. The backside illumination technology can increase the efficiency, but the crosstalk still remains an critical issue to improve the image quality of the CIS devices. In this paper, by adopting a parabolic color filter (P-CF), we demonstrate efficiency enhancement without any noticeable change in optical crosstalk of a backside illuminated 1.12 μm pixel CIS with deep-trench-isolation structure. To identify the observed results, we have investigated the effect of radius of curvature (r) of the P-CF on the efficiency and optical crosstalk of the CIS by performing an electromagnetic analysis. As the r of P-CF becomes equal to (or half) that of the microlens, the efficiencies of the B-, G-, and R-pixels increase by a factor of 14.1% (20.3%), 9.8% (15.3%), and 15.0% (15.7%) with respect to the flat CF cases without any noticeable crosstalk change. Also, as the incident angle increases up to 30°, the angular dependence of the efficiency and crosstalk significantly decreases by utilizing the P-CF in the CIS. Meanwhile, further reduction of r severely increases the optical crosstalk due to the increased diffraction effect, which has been confirmed with the simulated electric-field intensity distribution inside the devices.

  13. Task-sharing with nurses to enhance access to HIV treatment in Côte d'Ivoire.

    Science.gov (United States)

    McNairy, Margaret L; Bashi, Jules B; Chung, Hannah; Wemin, Louise; Lorng, Marie-Nicole Akpro; Brou, Hermann; Nioble, Cyprien; Lokossue, A; Abo, Kouame; Achi, Delphine; Ouattara, Kiyali; Sess, Daniel; Sanogo, Pongathie Adama; Ekra, Alexandre; Ettiegne-Traore, Virginie; Diabate, Conombo J; Abrams, Elaine J; El-Sadr, Wafaa M

    2017-04-01

    We report the first national programme in Côte d'Ivoire to evaluate the feasibility of nurse-led HIV care as a model of task-sharing with nurses to increase coverage and decentralisation of HIV services. Twenty-six public HIV facilities implemented either a nurse-with-onsite-physician or a nurse-with-visiting-physician model of HIV task-sharing. Routinely collected patient data were reviewed to analyse patient characteristics of those enrolling in care and initiating antiretroviral therapy (ART). Retention, loss to programme and death were compared across facility-level characteristics. A total of 1224 patients enrolled in HIV care, with 666 initiating ART, from January 2012 to May 2013 (median follow-up 13 months). The majority (94%) were adults ≥15 years. Fourteen facilities provided ART initiation for the first time during the pilot period; 20 facilities were primary level. Nurse-led care with a visiting physician was provided in 14 of the primary-level facilities. Nurse-led ART care with an onsite physician was provided in all secondary-level facilities and six of the primary-level facilities. During the pilot, 567 (85%) of patients were retained, 28 (4.2%) died, 47 (7.1%) were lost to follow-up, and 24 (3.6%) transferred. Five deaths (10.9%) were recorded among children as compared to 23 deaths (3.7%) among adults (P = 0.037). There were no differences in retention by model of nurse-led ART care. Task-sharing of HIV care and ART initiation with nurses in Côte d'Ivoire is feasible. This pilot illustrates two models of nurse-led HIV care and has informed national policy on nurse-led HIV care in Côte d'Ivoire. © 2017 John Wiley & Sons Ltd.

  14. Warm-adapted microbial communities enhance their carbon-use efficiency in warmed soils

    Science.gov (United States)

    Rousk, Johannes; Frey, Serita

    2017-04-01

    Ecosystem models predict that climate warming will stimulate microbial decomposition of soil carbon (C), resulting in a positive feedback to increasing temperatures. The current generation of models assume that the temperature sensitivities of microbial processes do not respond to warming. However, recent studies have suggested that the ability of microbial communities to adapt to warming can lead both strengthened and weakened feedbacks. A further complication is that the balance between microbial C used for growth to that used for respiration - the microbial carbon-use efficiency (CUE) - also has been shown through both modelling and empirical study to respond to warming. In our study, we set out to assess how chronic warming (+5°C over ambient during 9 years) of a temperate hardwood forest floor (Harvard Forest LTER, USA) affected temperature sensitivities of microbial processes in soil. To do this, we first determined the temperature relationships for bacterial growth, fungal growth, and respiration in plots exposed to warmed or ambient conditions. Secondly, we parametrised the established temperature functions microbial growth and respiration with plot-specific measured soil temperature data at a hourly time-resolution over the course of 3 years to estimate the real-time variation of in situ microbial C production and respiration. To estimate the microbial CUE, we also divided the microbial C production with the sum of microbial C production and respiration as a proxy for substrate use. We found that warm-adapted bacterial and fungal communities both shifted their temperature relationships to grow at higher rates in warm conditions which coincided with reduced rates at cool conditions. As such, their optimal temperature (Topt), minimum temperature (Tmin) and temperature sensitivity (Q10) were all increased. The temperature relationship for temperature, in contrast, was only marginally shifted in the same direction, but at a much smaller effect size, with

  15. Enhanced photosynthetic efficiency in trees world-wide by rising atmospheric CO2 levels

    Science.gov (United States)

    Ehlers, Ina; Wieloch, Thomas; Groenendijk, Peter; Vlam, Mart; van der Sleen, Peter; Zuidema, Pieter A.; Robertson, Iain; Schleucher, Jürgen

    2014-05-01

    signals is a fundamental advantage of isotopomer ratios (Augusti et al., Chem. Geol 2008). These results demonstrate that increasing [CO2] has reduced the ratio of photorespiration to photosynthesis on a global scale. Photorespiration is a side reaction that decreases the C gain of plants; the suppression of photorespiration in all analyzed trees indicates that increasing atmospheric [CO2] is enhancing the photosynthetic efficiency of trees world-wide. The consensus response of the trees agrees with the response of annual plants in greenhouse experiments, with three important conclusions. First, the generality of the isotopomer shift confirms that the CO2 response reflects the ratio of photosynthesis to photorespiration, and that it creates a robust signal in tree rings. Second, the agreement between greenhouse-grown plants and trees indicates that there has not been an acclimation response of the trees during the past centuries. Third, the results show that the regulation of tree gas exchange has during past centuries been governed by the same rules as observed in manipulative experiments, in contradiction to recent reports (Keenan et al., Nature 2013).

  16. Light extraction efficiency enhancement for fluorescent SiC based white light-emitting diodes

    DEFF Research Database (Denmark)

    Ou, Haiyan; Ou, Yiyu; Argyraki, Aikaterini

    Fluorescent SiC based white light-emitting diodes(LEDs) light source, as an innovative energy-efficient light source, would even have longer lifetime, better light quality and eliminated blue-tone effect, compared to the current phosphor based white LED light source. In this paper, the yellow....... At a device level, the focus is on improving the light extraction efficiency due to the rather high refractive index of SiC by nanostructuring the surface of SiC. Both periodic nanostructures made by e-beam lithography and nanosphere lithography and random nanostructures made by self-assembled Au nanosphere...... fluorescent Boron-Nitrogen co-doped 6H SiC is optimized in terms of source material, growth condition, dopant concentration, and carrier lifetime by using photoluminescence, pump-probe spectroscopy etc. The internal quantum efficiency is measured and the methods to increase the efficiency have been explored...

  17. Efficiency of enhanced oil recovery using polymer-augmented low salinity flooding

    National Research Council Canada - National Science Library

    Almansour, Abdullah O; AlQuraishi, Abdulrahman A; AlHussinan, Saud N; AlYami, Hamdan Q

    2017-01-01

    Oil recovery from heavy oil resources has always been a challenging task. This work is aimed at investigating the recovery efficiency of polymer-augmented low salinity waterflooding in heavy oil reservoirs...

  18. Enhancement of the power conversion efficiency for organic photovoltaic cells with a Liq/bathocuproine electron transport bilayer

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ke; Kim, Dae Hun; Lee, Se Han; Kim, Tae Whan, E-mail: twk@hanyang.ac.kr

    2013-11-29

    Organic photovoltaic (OPV) cells based on a poly(3-hexylthiophene) (P3HT):fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) active layer with a bathocuproine (BCP)/8-hydroxyquinoline lithium (Liq) electron transport layer were fabricated to enhance their power conversion efficiency (PCE). Absorbance spectra showed that the absorbance intensity of the spectra for the P3HT:PCBM active layer with a Liq layer in the wavelength between 500 and 600 nm was enhanced due to the damage of the active layer. The PCE of the fabricated OPV cells with a Liq/BCP layer was significantly enhanced by up to 4.29% in comparison with that of OPV cells with a BCP or a Liq layer. - Highlights: • Organic photovoltaic cell with a bathocuproine (BCP)/8-hydroxyquinoline lithium (Liq) layer. • The BCP layer prevented the performance deterioration. • The efficiency of the photovoltaic cell with a BCP/Liq layer was enhanced.

  19. Influence of demand-side measures to enhance renin-angiotensin prescribing efficiency in Europe: implications for the future.

    Science.gov (United States)

    Vončina, Luka; Strizrep, Tihomir; Godman, Brian; Bennie, Marion; Bishop, Iain; Campbell, Stephen; Vlahović-Palčevski, Vera; Gustafsson, Lars L

    2011-08-01

    European countries strive to enhance prescribing efficiency. This includes renin-angiotensin drugs following the availability of generic angiotensin-converting enzyme inhibitors (ACEIs). To compare angiotensin receptor blocker utilization and expenditure patterns in Austria and Croatia following prescribing restrictions, as well as with other European countries introducing different supply- and demand-side measures. Lastly, to appraise the impact of generic losartan in Croatia on utilization of patented angiotensin receptor blockers. Observational retrospective study principally between 2001 and 2007, using defined daily doses and €/1000 inhabitants/year. Demand-side measures were based on the four 'E's - education, engineering, economics and enforcement. Greater intensity of follow-up of prescribing restrictions in Croatia enhanced utilization of ACEIs versus Austria. There was high utilization of ACEIs in Scotland following intensive demand-side measures, similar to Austria and Croatia. Demand-side measures in Spain (Catalonia) and Sweden also appeared to moderate angiotensin receptor blockers utilization. The combination of measures helped stabilize expenditure on renin-angiotensin drugs when adjusted for population sizes despite appreciable increases in volumes. The only exception was Portugal, with less intensive measures. Multiple and intensive demand-side measures enhanced prescribing efficiency. The more intense follow-up of ARB prescribing restrictions in Croatia had a greater influence on subsequent utilization patterns than Austria. Both findings confirm earlier studies. Reforms also favorably enhanced the prescribing of generic losartan once available.

  20. Infection of Early and Young Callus Tissues of Indica Rice BPT 5204 Enhances Regeneration and Transformation Efficiency

    Directory of Open Access Journals (Sweden)

    P. MANIMARAN

    2013-11-01

    Full Text Available A rapid and reproducible method to develop transgenic plants with enhanced transformation efficiency using Agrobacterium has been developed for the elite indica rice variety BPT 5204. Different rice calli aged from 3 to 30 d were co-cultivated with pre-incubated Agrobacterium suspension culture (LBA4404: pSB1, pCAMBIA1301 and incubated in dark for 3 d. Based on the transient GUS gene expression analysis, 6-day-old young calli showed high transformation frequency followed by 21-day-old ones. Thus, both 6- and 21-day-old calli were used for assessing the stable transformation efficiency. It was observed that the 6-day-old young transformed calli showed about 2-fold higher regeneration frequency when compared with 21-day-old calli. The transformation efficiency was enhanced for young calli to 5.9% compared with 0.8% of the 21-day-old calli. Molecular and genetic analysis of transgenic plants (T0 revealed the presence of 1–2 copies of T-DNA integration in transformants and it follows Mendalian ratio in T1 transgenic plants. From the present study, it was concluded that the development of transgenic rice plants in less duration with high regeneration and transformation efficiency was achieved in BPT 5204 by using 6-day-old young calli as explants.

  1. Perylene Bisimide as a Promising Zinc Oxide Surface Modifier: Enhanced Interfacial Combination for Highly Efficient Inverted Polymer Solar Cells.

    Science.gov (United States)

    Nian, Li; Zhang, Wenqiang; Wu, Siping; Qin, Leiqiang; Liu, Linlin; Xie, Zengqi; Wu, Hongbin; Ma, Yuguang

    2015-11-25

    We report the application of a perylene bisimide (PBI-H) as zinc oxide (ZnO) surface modifier to afford an organic-inorganic co-interlayer for highly efficient inverted organic photovoltaics (i-OPV). By thermal annealing, a N-Zn chemical bond formed between PBI-H and ZnO, inducing close organic-inorganic combination. In addition, this co-interlayer shows decreased work function and increased electron transportation and conductivity, which are benefits for the cathode to enhance charge extraction efficiency and decrease recombination losses. As a result a highly efficient i-OPV was achieved with a power conversion efficiency (PCE) of 9.43% based on this co-interlayer with PTB7:PC71BM as the active layer, which shows over 35% enhancement compared to that of the device without the PBI-H layer. Moreover, this co-interlayer was widely applicable for i-OPVs based on various material systems, such as P3HT:PC61BM and PTB7-Th:PC71BM, resulting in PCE as high as 4.78% and 10.31%, respectively.

  2. Enhancement of photoconversion efficiency in dye-sensitized solar cells exploiting pulsed laser deposited niobium pentoxide blocking layers

    Energy Technology Data Exchange (ETDEWEB)

    Sacco, Adriano, E-mail: adriano.sacco@iit.it [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Di Bella, Maurizio Salvatore [Department of Energy, Information Engineering and Mathematical Models (DEIM), Thin Films Laboratory, Università di Palermo, Viale delle Scienze, Building 9, 90128 Palermo (Italy); Gerosa, Matteo [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Applied Science and Technology Department (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Chiodoni, Angelica; Bianco, Stefano [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Mosca, Mauro; Macaluso, Roberto; Calì, Claudio [Department of Energy, Information Engineering and Mathematical Models (DEIM), Thin Films Laboratory, Università di Palermo, Viale delle Scienze, Building 9, 90128 Palermo (Italy); Pirri, Candido Fabrizio [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Applied Science and Technology Department (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2015-01-01

    Among all the photovoltaic technologies developed so far, dye-sensitized solar cells are considered as a promising alternative to the expensive and environmentally unfriendly crystalline silicon-based solar cells. One of the possible strategies employed to increase their photovoltaic efficiency is to reduce the charge recombination at the cell conductive substrate through the use of a compact blocking layer. In this paper, we report on the fabrication and characterization of dye-sensitized solar cells employing niobium pentoxide (Nb{sub 2}O{sub 5}) thin film blocking layer deposited through the pulsed laser deposition technique on conductive substrates. The careful selection of the optimal film thickness led to a 30% enhancement of the photoconversion efficiency with respect to reference cells fabricated without blocking layer. Open circuit voltage decay and electrochemical impedance spectroscopy techniques proved that the effective suppression of the charge recombination occurring at the substrate/electrolyte interface represents the main reason for the improvement of the photovoltaic efficiency. - Highlights: • Niobium pentoxide thin films were fabricated through pulsed laser deposition. • The deposited films were employed as recombination blocking layer in DSCs. • The selection of the optimal film thickness led to the enhancement of the efficiency.

  3. The third helix of the Hoxc8 homeodomain peptide enhances the efficiency of gene transfer in combination with lipofectamine.

    Science.gov (United States)

    Gadi, Jogeswar; Ruthala, Kalyani; Kong, Kyoung-Ah; Park, Hyoung Woo; Kim, Myoung Hee

    2009-05-01

    Protein transduction domains (PTDs) have been shown to cross the biological cell membranes efficiently through a receptor and energy independent mechanism. Because of its ease in membrane transducing ability, PTDs could be used as a gene delivery vector. Since we already have shown that purified Hoxc8 homeoprotein has the ability to cross the cellular membrane, we analyzed the possibility of the third helix of the Hoxc8 homeodomain as a useful gene delivery vector. For that purpose, a 16-aa long synthetic oligopeptide Hoxc8 Protein Transduction Domain (HPTD) was chemically synthesized and then tested to see whether the HPTD could form a complex with DNA or not. Gel retardation analysis revealed that the HPTD interacts with plasmid DNA efficiently but failed to transfer the DNA into the cells. However, HPTD can enhance the efficiency of gene transfer in combination with Lipofectamine which doubled the gene transfer rate into COS-7 cells compared with the DNA/Lipofectamine control. An MTT assay indicated that the amount of HPTD used in the complex for the transfection did not show any cytotoxicty in COS-7 cells. The TEM studies showed compact particle formation in the presence of HPTD. These results indicate that the HPTD could be a good candidate adjuvant molecule to enhance the gene transfer efficiency of Lipofectamine in eukaryotic cells.

  4. Enhanced Sensitivity for Detection of HIV-1 p24 Antigen by a Novel Nuclease-Linked Fluorescence Oligonucleotide Assay.

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    Peihu Fan

    Full Text Available The relatively high detection limit of the Enzyme-linked immunosorbent assay (ELISA prevents its application for detection of low concentrations of antigens. To increase the sensitivity for detection of HIV-1 p24 antigen, we developed a highly sensitive nuclease-linked fluorescence oligonucleotide assay (NLFOA. Two major improvements were incorporated in NLFOA to amplify antibody-antigen interaction signals and reduce the signal/noise ratio; a large number of nuclease molecules coupled to the gold nanoparticle/streptavidin complex and fluorescent signals generated from fluorescent-labeled oligonucleotides by the nuclease. The detection limit of p24 by NLFOA was 1 pg/mL, which was 10-fold more sensitive than the conventional ELISA (10 pg/mL. The specificity was 100% and the coefficient of variation (CV was 7.8% at low p24 concentration (1.5 pg/mL with various concentrations of spiked p24 in HIV-1 negative sera. Thus, NLFOA is highly sensitive, specific, reproducible and user-friendly. The more sensitive detection of low p24 concentrations in HIV-1-infected individuals by NLFOA could allow detection of HIV-1 infections that are missed by the conventional ELISA at the window period during acute infection to further reduce the risk for HIV-1 infection due to the undetected HIV-1 in the blood products. Moreover, NLFOA can be easily applied to more sensitive detection of other antigens.

  5. USE OF IMAGE ENHANCEMENT TECHNIQUES FOR IMPROVING REAL TIME FACE RECOGNITION EFFICIENCY ON WEARABLE GADGETS

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    MUHAMMAD EHSAN RANA

    2017-01-01

    Full Text Available The objective of this research is to study the effects of image enhancement techniques on face recognition performance of wearable gadgets with an emphasis on recognition rate.In this research, a number of image enhancement techniques are selected that include brightness normalization, contrast normalization, sharpening, smoothing, and various combinations of these. Subsequently test images are obtained from AT&T database and Yale Face Database B to investigate the effect of these image enhancement techniques under various conditions such as change of illumination and face orientation and expression.The evaluation of data, collected during this research, revealed that the effect of image pre-processing techniques on face recognition highly depends on the illumination condition under which these images are taken. It is revealed that the benefit of applying image enhancement techniques on face images is best seen when there is high variation of illumination among images. Results also indicate that highest recognition rate is achieved when images are taken under low light condition and image contrast is enhanced using histogram equalization technique and then image noise is reduced using median smoothing filter. Additionally combination of contrast normalization and mean smoothing filter shows good result in all scenarios. Results obtained from test cases illustrate up to 75% improvement in face recognition rate when image enhancement is applied to images in given scenarios.

  6. Efficiency Enhancement for an Inductive Wireless Power Transfer System by Optimizing the Impedance Matching Networks.

    Science.gov (United States)

    Miao, Zhidong; Liu, Dake; Gong, Chen

    2017-10-01

    Inductive wireless power transfer (IWPT) is a promising power technology for implantable biomedical devices, where the power consumption is low and the efficiency is the most important consideration. In this paper, we propose an optimization method of impedance matching networks (IMN) to maximize the IWPT efficiency. The IMN at the load side is designed to achieve the optimal load, and the IMN at the source side is designed to deliver the required amount of power (no-more-no-less) from the power source to the load. The theoretical analyses and design procedure are given. An IWPT system for an implantable glaucoma therapeutic prototype is designed as an example. Compared with the efficiency of the resonant IWPT system, the efficiency of our optimized system increases with a factor of 1.73. Besides, the efficiency of our optimized IWPT system is 1.97 times higher than that of the IWPT system optimized by the traditional maximum power transfer method. All the discussions indicate that the optimization method proposed in this paper could achieve a high efficiency and long working time when the system is powered by a battery.

  7. Application of biuret, dicyandiamide, or urea as a cathode buffer layer toward the efficiency enhancement of polymer solar cells.

    Science.gov (United States)

    Zhao, Xuemei; Xu, Chenhui; Wang, Haitao; Chen, Fei; Zhang, Wenfeng; Zhao, Zhiqiang; Chen, Liwei; Yang, Shangfeng

    2014-03-26

    Three amino-containing small-molecule organic materials-biuret, dicyandiamide (DCDA), and urea-were successfully applied as novel cathode buffer layers (CBLs) in P3HT:PCBM bulk heterojunction polymer solar cells (BHJ-PSCs) for the first time, resulting in obvious efficiency enhancement. Under the optimized condition, the power conversion efficiencies (PCEs) of the CBL-incorporated BHJ-PSC devices are 3.84%, 4.25%, and 4.39% for biuret, DCDA, and urea, which are enhanced by ∼15%, ∼27%, and ∼31%, respectively, compared to the reference poly(3-hexylthiophene-2,5-diyl) : [6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) BHJ-PSC device without any CBL. The efficiency enhancement is primarily attributed to the increases of both short-circuit current density (Jsc) and fill factor (FF), for which the enhancement ratio is found to be sensitively dependent on the molecular structure of small-molecule organic materials. The surface morphologies and surface potential changes of the CBL-incorporated P3HT:PCBM photoactive layers were studied by atomic force microscopy and scanning Kelvin probe microscopy, respectively, suggesting the formation of an interfacial dipole layer between the photoactive layer and Al cathode, which may decrease the energy level offset between the work function of Al and the lowest unoccipoed molecular orbital level (LUMO) of the PCBM acceptor and consequently facilitate electron extraction by the Al cathode. The difference in the enhancement effect of biuret, DCDA, and urea is due to their difference on the work function matching with P3HT:PCBM. Besides, the coordination interaction between the lone-pair electrons on the N atoms of the amino (-NH2) group and the Al atoms may prohibit interaction between Al and the thiophene rings of P3HT, contributing to the efficiency enhancement of the CBL-incorporated devices as well. In this sense, the different CBL performance of biuret, DCDA, and urea is also proposed to partially originate from the

  8. Efficient expression of nuclear transgenes in the green alga Chlamydomonas: synthesis of an HIV antigen and development of a new selectable marker.

    Science.gov (United States)

    Barahimipour, Rouhollah; Neupert, Juliane; Bock, Ralph

    2016-03-01

    The unicellular green alga Chlamydomonas reinhardtii has become an invaluable model system in plant biology. There is also considerable interest in developing this microalga into an efficient production platform for biofuels, pharmaceuticals, green chemicals and industrial enzymes. However, the production of foreign proteins in the nucleocytosolic compartment of Chlamydomonas is greatly hampered by the inefficiency of transgene expression from the nuclear genome. We have recently addressed this limitation by isolating mutant algal strains that permit high-level transgene expression and by determining the contributions of GC content and codon usage to gene expression efficiency. Here we have applied these new tools and explored the potential of Chlamydomonas to produce a recombinant biopharmaceutical, the HIV antigen P24. We show that a codon-optimized P24 gene variant introduced into our algal expression strains give rise to recombinant protein accumulation levels of up to 0.25% of the total cellular protein. Moreover, in combination with an expression strain, a resynthesized nptII gene becomes a highly efficient selectable marker gene that facilitates the selection of transgenic algal clones at high frequency. By establishing simple principles of successful transgene expression, our data open up new possibilities for biotechnological research in Chlamydomonas.

  9. AN IMPROVED BIT LOADING TECHNIQUE FOR ENHANCED ENERGY EFFICIENCY IN NEXT GENERATION VOICE/VIDEO APPLICATIONS

    Directory of Open Access Journals (Sweden)

    VINOTH BABU K.

    2016-04-01

    Full Text Available Multi input multi output (MIMO and orthogonal frequency division multiplexing (OFDM are the key techniques for the future wireless communication systems. Previous research in the above areas mainly concentrated on spectral efficiency improvement and very limited work has been done in terms of energy efficient transmission. In addition to spectral efficiency improvement, energy efficiency improvement has become an important research because of the slow progressing nature of the battery technology. Since most of the user equipments (UE rely on battery, the energy required to transmit the target bits should be minimized to avoid quick battery drain. The frequency selective fading nature of the wireless channel reduces the spectral and energy efficiency of OFDM based systems. Dynamic bit loading (DBL is one of the suitable solution to improve the spectral and energy efficiency of OFDM system in frequency selective fading environment. Simple dynamic bit loading (SDBL algorithm is identified to offer better energy efficiency with less system complexity. It is well suited for fixed data rate voice/video applications. When the number of target bits are very much larger than the available subcarriers, the conventional single input single output (SISO-SDBL scheme offers high bit error rate (BER and needs large transmit energy. To improve bit error performance we combine space frequency block codes (SFBC with SDBL, where the adaptations are done in both frequency and spatial domain. To improve the quality of service (QoS further, optimal transmit antenna selection (OTAS scheme is also combined with SFBC-SDBL scheme. The simulation results prove that the proposed schemes offer better QoS when compared to the conventional SISOSDBL scheme.

  10. Enhanced Trapping of HIV-1 by Human Cervicovaginal Mucus Is Associated with Lactobacillus crispatus-Dominant Microbiota.

    Science.gov (United States)

    Nunn, Kenetta L; Wang, Ying-Ying; Harit, Dimple; Humphrys, Michael S; Ma, Bing; Cone, Richard; Ravel, Jacques; Lai, Samuel K

    2015-10-06

    Cervicovaginal mucus (CVM) can provide a barrier that precludes HIV and other sexually transmitted virions from reaching target cells in the vaginal epithelium, thereby preventing or reducing infections. However, the barrier properties of CVM differ from woman to woman, and the causes of these variations are not yet well understood. Using high-resolution particle tracking of fluorescent HIV-1 pseudoviruses, we found that neither pH nor Nugent scores nor total lactic acid levels correlated significantly with virus trapping in unmodified CVM from diverse donors. Surprisingly, HIV-1 was generally trapped in CVM with relatively high concentrations of d-lactic acid and a Lactobacillus crispatus-dominant microbiota. In contrast, a substantial fraction of HIV-1 virions diffused rapidly through CVM with low concentrations of d-lactic acid that had a Lactobacillus iners-dominant microbiota or significant amounts of Gardnerella vaginalis, a bacterium associated with bacterial vaginosis. Our results demonstrate that the vaginal microbiota, including specific species of Lactobacillus, can alter the diffusional barrier properties of CVM against HIV and likely other sexually transmitted viruses and that these microbiota-associated changes may account in part for the elevated risks of HIV acquisition linked to bacterial vaginosis or intermediate vaginal microbiota. Variations in the vaginal microbiota, especially shifts away from Lactobacillus-dominant microbiota, are associated with differential risks of acquiring HIV or other sexually transmitted infections. However, emerging evidence suggests that Lactobacillus iners frequently colonizes women with recurring bacterial vaginosis, raising the possibility that L. iners may not be as protective as other Lactobacillus species. Our study was designed to improve understanding of how the cervicovaginal mucus barrier against HIV may vary between women along with the vaginal microbiota and led to the finding that the vaginal microbiota

  11. Efficiency of HIV/AIDS health centers and effect of community-based health insurance and performance-based financing on HIV/AIDS service delivery in Rwanda.

    Science.gov (United States)

    Zeng, Wu; Rwiyereka, Angelique K; Amico, Peter R; Avila-Figueroa, Carlos; Shepard, Donald S

    2014-04-01

    This study evaluates the efficiency of rural health centers in Rwanda in delivering the three key human immunodeficiency virus/acquired immunodeficiency syndrome services: antiretroviral treatment, prevention of mother-to-child transmission, and voluntary counseling and testing using data envelopment analysis, and assesses the impact of community-based health insurance (CBHI) and performance-based financing on improving the delivery of the three services. Results show that health centers average efficiency of 78%, and despite the observed variation, the performance increased by 15.6% from 2006 through 2007. When the services are examined separately, each 1% growth of CBHI use was associated with 3.7% more prevention of mother-to-child transmission and 2.5% more voluntary counseling and testing services. Although more health centers would have been needed to evaluate performance-based financing, we found that high use of CBHI in Rwanda was an important contributor to improving human immunodeficiency virus/acquired immunodeficiency syndrome services in rural health centers in Rwanda.

  12. Bovine thrombin enhances the efficiency and specificity of polymerase chain reaction.

    Science.gov (United States)

    Zhang, Ying; Li, Xiaoning; Zou, Ruxing; Xue, Ying; Lou, Xinhui; He, Miao

    2014-12-01

    The polymerase chain reaction (PCR) has become one of the central techniques in molecular biology since its invention. However, PCR can be fraught with difficulties in various situations, and it is desirable to find novel PCR enhancers suitable for universal applications. Here we show that bovine thrombin (BT), a well-known coagulation protein, is exceptionally effective at preventing the formation of primer dimers and enhancing the formation of the desired PCR products. The PCR enhancement effects of BT were demonstrated by testing various types of samples, including low-copy synthetic single-stranded DNAs (ssDNAs), synthetic ssDNA pools, human genomic DNA, and hepatitis B virus genomic DNA. In addition, BT was also able to effectively relieve PCR inhibition by nanomaterial inhibitors such as gold nanoparticles (AuNPs) and graphene oxide (GO). Compared with BSA, one of the most popular PCR enhancers, BT was more effective and required concentrations 18-178 times less than that of BSA to achieve a similar level of PCR enhancement.

  13. Enhancement of Energy Efficiency and Food Product Quality Using Adsorption Dryer with Zeolite

    Directory of Open Access Journals (Sweden)

    Moh Djaeni

    2013-06-01

    Full Text Available Drying is a basic operation in wood, food, pharmaceutical and chemical industry. Currently, several drying methods are often not efficient in terms of energy consumption (energy efficiency of 20-60% and have an impact on product quality degradation due to the introduction of operational temperature upper 80oC. This work discusses the development of adsorption drying with zeolite to improve the energy efficiency as well as product quality. In this process, air as drying medium is dehumidified by zeolite. As a result humidity of air can be reduced up to 0.1 ppm. So, for heat sensitive products, the drying process can be performed in low or medium temperature with high driving force. The study has been conducted in three steps: designing the dryer, performing laboratory scale equipment (tray, spray, and fluidised bed dryers with zeolite, and evaluating the dryer performance based on energy efficiency and product quality. Results showed that the energy efficiency of drying process is 15-20% higher than that of conventional dryer. In additon, the dryer can speed up drying time as well as retaining product quality.

  14. Efficiency Enhancement of Hybrid Perovskite Solar Cells with MEH-PPV Hole-Transporting Layers

    Science.gov (United States)

    Chen, Hsin-Wei; Huang, Tzu-Yen; Chang, Ting-Hsiang; Sanehira, Yoshitaka; Kung, Chung-Wei; Chu, Chih-Wei; Ikegami, Masashi; Miyasaka, Tsutomu; Ho, Kuo-Chuan

    2016-01-01

    In this study, hybrid perovskite solar cells are fabricated using poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and poly(3-hexylthiophene-2,5-diyl) (P3HT) as dopant-free hole-transporting materials (HTMs), and two solution processes (one- and two-step methods, respectively) for preparing methylammonium lead iodide perovskite. By optimizing the concentrations and solvents of MEH-PPV solutions, a power conversion efficiency of 9.65% with hysteresis-less performance is achieved, while the device with 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′spirobifluorene (Spiro-OMeTAD) doped with lithium salts and tert-butylpyridine (TBP) exhibits an efficiency of 13.38%. This result shows that non-doped MEH-PPV is a suitable, low-cost HTM for efficient polymer-based perovskite solar cells. The effect of different morphologies of methylammonium lead iodide perovskite on conversion efficiency is also investigated by incident photon-to-electron conversion efficiency (IPCE) curves and electrochemical impedance spectroscopy (EIS). PMID:27698464

  15. K70Q adds high-level tenofovir resistance to "Q151M complex" HIV reverse transcriptase through the enhanced discrimination mechanism.

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    Atsuko Hachiya

    2011-01-01

    Full Text Available HIV-1 carrying the "Q151M complex" reverse transcriptase (RT mutations (A62V/V75I/F77L/F116Y/Q151M, or Q151Mc is resistant to many FDA-approved nucleoside RT inhibitors (NRTIs, but has been considered susceptible to tenofovir disoproxil fumarate (TFV-DF or TDF. We have isolated from a TFV-DF-treated HIV patient a Q151Mc-containing clinical isolate with high phenotypic resistance to TFV-DF. Analysis of the genotypic and phenotypic testing over the course of this patient's therapy lead us to hypothesize that TFV-DF resistance emerged upon appearance of the previously unreported K70Q mutation in the Q151Mc background. Virological analysis showed that HIV with only K70Q was not significantly resistant to TFV-DF. However, addition of K70Q to the Q151Mc background significantly enhanced resistance to several approved NRTIs, and also resulted in high-level (10-fold resistance to TFV-DF. Biochemical experiments established that the increased resistance to tenofovir is not the result of enhanced excision, as K70Q/Q151Mc RT exhibited diminished, rather than enhanced ATP-based primer unblocking activity. Pre-steady state kinetic analysis of the recombinant enzymes demonstrated that addition of the K70Q mutation selectively decreases the binding of tenofovir-diphosphate (TFV-DP, resulting in reduced incorporation of TFV into the nascent DNA chain. Molecular dynamics simulations suggest that changes in the hydrogen bonding pattern in the polymerase active site of K70Q/Q151Mc RT may contribute to the observed changes in binding and incorporation of TFV-DP. The novel pattern of TFV-resistance may help adjust therapeutic strategies for NRTI-experienced patients with multi-drug resistant (MDR mutations.

  16. Asn 362 in gp120 contributes to enhanced fusogenicity by CCR5-restricted HIV-1 envelope glycoprotein variants from patients with AIDS

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    Wang Bin

    2007-12-01

    Full Text Available Abstract Background CCR5-restricted (R5 human immunodeficiency virus type 1 (HIV-1 variants cause CD4+ T-cell loss in the majority of individuals who progress to AIDS, but mechanisms underlying the pathogenicity of R5 strains are poorly understood. To better understand envelope glycoprotein (Env determinants contributing to pathogenicity of R5 viruses, we characterized 37 full-length R5 Envs from cross-sectional and longitudinal R5 viruses isolated from blood of patients with asymptomatic infection or AIDS, referred to as pre-AIDS (PA and AIDS (A R5 Envs, respectively. Results Compared to PA-R5 Envs, A-R5 Envs had enhanced fusogenicity in quantitative cell-cell fusion assays, and reduced sensitivity to inhibition by the fusion inhibitor T-20. Sequence analysis identified the presence of Asn 362 (N362, a potential N-linked glycosylation site immediately N-terminal to CD4-binding site (CD4bs residues in the C3 region of gp120, more frequently in A-R5 Envs than PA-R5 Envs. N362 was associated with enhanced fusogenicity, faster entry kinetics, and increased sensitivity of Env-pseudotyped reporter viruses to neutralization by the CD4bs-directed Env mAb IgG1b12. Mutagenesis studies showed N362 contributes to enhanced fusogenicity of most A-R5 Envs. Molecular models indicate N362 is located adjacent to the CD4 binding loop of gp120, and suggest N362 may enhance fusogenicity by promoting greater exposure of the CD4bs and/or stabilizing the CD4-bound Env structure. Conclusion Enhanced fusogenicity is a phenotype of the A-R5 Envs studied, which was associated with the presence of N362, enhanced HIV-1 entry kinetics and increased CD4bs exposure in gp120. N362 contributes to fusogenicity of R5 Envs in a strain dependent manner. Our studies suggest enhanced fusogenicity of A-R5 Envs may contribute to CD4+ T-cell loss in subjects who progress to AIDS whilst harbouring R5 HIV-1 variants. N362 may contribute to this effect in some individuals.

  17. HIV Transmission

    Science.gov (United States)

    ... Abroad Treatment Basic Statistics Get Tested Find an HIV testing site near you. Enter ZIP code or city Follow HIV/AIDS CDC HIV CDC HIV/AIDS See RSS | ... on HIV Syndicated Content Website Feedback HIV/AIDS HIV Transmission Language: English (US) Español (Spanish) Recommend on ...

  18. Enhancing Adherence to Care in the HIV Care Continuum: The Barrier Elimination and Care Navigation (BEACON) Project Evaluation.

    Science.gov (United States)

    Shacham, Enbal; López, Julia D; Brown, Tawyna M; Tippit, Kristen; Ritz, Ann

    2018-01-01

    Interventions are needed to address each phase of the HIV care continuum in order to improve health outcomes and reduce likelihood of HIV transmission. The purpose of this study was to assess the impact of a community- and clinic-based intervention designed and implemented to reengage individuals who were lost to HIV care. Eligible participants had either never engaged in HIV care or had not had a medical visit for at least 12 months. Participants enrolled in a community- and clinic-based intervention that included intensive case management, access to a community nurse and peer navigator, as well as emergency stabilization funds. Data were collected at baseline and 6-month time points by the case managers; which included sociodemographics, general health, abstracted HIV viral loads and CD4 cell counts from their medical records. Descriptive and GEE analyses were conducted to assess changes from baseline to 6 months. A total of 322 participants enrolled over a 5-year period, of whom the majority were male (n = 250) and African American with a mean age of 42.0 years. After 6 months of the intervention, there was a significant increase of individuals who had undetectable HIV viral loads and their median CD4 cell counts increased (p < 0.01 for both). General health improved as well (p < 0.01). It is clear that this method of engagement, while staff intensive, is successful at engaging and retaining individuals in HIV care at least through 6 months.

  19. Novel outreach settings to enhance sexually transmitted infection/HIV awareness, diagnosis and treatment in hard-to-reach populations.

    Science.gov (United States)

    Lampejo, T; Turner, R; Roberts, C; Allen, K; Watson, L; Caverley-Frost, L; Scott, P; Ostridge, E; Cooney, G; Hardy, J; Nulty, K; Day, S

    2018-03-01

    Despite recent rises in the number of cases of sexually transmitted infections (STIs) such as syphilis and gonorrhoea in England and increasing rates of HIV diagnosis among several men who have sex with men populations, many individuals are still not engaging with sexual health services. The John Hunter Clinic for Sexual Health, Chelsea and Westminster Hospital, London set up outreach clinics at the two world's largest adult lifestyle exhibitions in 2013 and 2015. This was the first time that a sexual health screening and promotion service was available at these large-scale (over 10,000 attendees at each) adult lifestyle events. A total of 381 individuals underwent STI screening across the two events. Nineteen (5.0%) patients were diagnosed with an infection. Twelve (3.1%) patients with Chlamydia trachomatis, three (0.8%) patients with syphilis, one (0.3%) patient with Neisseria gonorrhoeae, one (0.3%) patient with HIV, one (0.3%) patient with hepatitis B and one (0.3%) patient with hepatitis C. All 19 patients were promptly contacted with their results and had arrangements made for treatment or were referred for specialist follow up. Where possible, contact tracing was also performed. Implementing such outreach-based projects is challenged by lack of on-site laboratory support, high staffing demands and potentially high costs. However, we achieved a total HIV screening uptake rate of 94.5% amongst our outreach clinic attendees (versus 67% nationally in conventional sexual health clinic attendees) with an HIV positivity rate of 0.3% (versus 0.2% nationally in high HIV prevalence band populations). Additionally, 30.7% had never been tested for HIV previously (versus 20.7% nationally). Our work demonstrates that these strategies can help to address issues related to lack of STI/HIV screening in hard-to-reach populations and promote risk reduction behaviour.

  20. Cost-Effectiveness of Enhanced Syphilis Screening among HIV-Positive Men Who Have Sex with Men: A Microsimulation Model

    Science.gov (United States)

    Tuite, Ashleigh R.; Burchell, Ann N.; Fisman, David N.

    2014-01-01

    Background Syphilis co-infection risk has increased substantially among HIV-infected men who have sex with men (MSM). Frequent screening for syphilis and treatment of men who test positive might be a practical means of controlling the risk of infection and disease sequelae in this population. Purpose We evaluated the cost-effectiveness of strategies that increased the frequency and population coverage of syphilis screening in HIV-infected MSM receiving HIV care, relative to current standard of care. Methods We developed a state-transition microsimulation model of syphilis natural history and medical care in HIV-infected MSM receiving care for HIV. We performed Monte Carlo simulations using input data derived from a large observational cohort in Ontario, Canada, and from published biomedical literature. Simulations compared usual care (57% of the population screened annually) to different combinations of more frequent (3- or 6-monthly) screening and higher coverage (100% screened). We estimated expected disease-specific outcomes, quality-adjusted survival, costs, and cost-effectiveness associated with each strategy from the perspective of a public health care payer. Results Usual care was more costly and less effective than strategies with more frequent or higher coverage screening. Higher coverage strategies (with screening frequency of 3 or 6 months) were expected to be cost-effective based on usually cited willingness-to-pay thresholds. These findings were robust in the face of probabilistic sensitivity analyses, alternate cost-effectiveness thresholds, and alternate assumptions about duration of risk, program characteristics, and management of underlying HIV. Conclusions We project that higher coverage and more frequent syphilis screening of HIV-infected MSM would be a highly cost-effective health intervention, with many potentially viable screening strategies projected to both save costs and improve health when compared to usual care. The baseline requirement

  1. Recombination Enhances HIV-1 Envelope Diversity by Facilitating the Survival of Latent Genomic Fragments in the Plasma Virus Population.

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    Taina T Immonen

    2015-12-01

    Full Text Available HIV-1 is subject to immune pressure exerted by the host, giving variants that escape the immune response an advantage. Virus released from activated latent cells competes against variants that have continually evolved and adapted to host immune pressure. Nevertheless, there is increasing evidence that virus displaying a signal of latency survives in patient plasma despite having reduced fitness due to long-term immune memory. We investigated the survival of virus with latent envelope genomic fragments by simulating within-host HIV-1 sequence evolution and the cycling of viral lineages in and out of the latent reservoir. Our model incorporates a detailed mutation process including nucleotide substitution, recombination, latent reservoir dynamics, diversifying selection pressure driven by the immune response, and purifying selection pressure asserted by deleterious mutations. We evaluated the ability of our model to capture sequence evolution in vivo by comparing our simulated sequences to HIV-1 envelope sequence data from 16 HIV-infected untreated patients. Empirical sequence divergence and diversity measures were qualitatively and quantitatively similar to those of our simulated HIV-1 populations, suggesting that our model invokes realistic trends of HIV-1 genetic evolution. Moreover, reconstructed phylogenies of simulated and patient HIV-1 populations showed similar topological structures. Our simulation results suggest that recombination is a key mechanism facilitating the persistence of virus with latent envelope genomic fragments in the productively infected cell population. Recombination increased the survival probability of latent virus forms approximately 13-fold. Prevalence of virus with latent fragments in productively infected cells was observed in only 2% of simulations when we ignored recombination, while the proportion increased to 27% of simulations when we allowed recombination. We also found that the selection pressures exerted

  2. Efficiency Enhancement of a Low-Voltage Automotive Vacuum Cleaner Using a Switched Reluctance Motor

    Directory of Open Access Journals (Sweden)

    Han-Geol Seon

    2016-08-01

    Full Text Available A recent increase in the number of diverse leisure activities and family outdoor activities has increased the need for the automobile-embedded vacuum cleaner. To date, this technology has not been applied in Korea and development efforts are not underway. Many of the existing portable cleaners connecting to the lighter jack of the vehicle use a direct current motor (DC motor. However, they do not have sufficient suction power to satisfy consumers; moreover, they have low durability and efficiency. In this paper, we therefore propose a technology for increasing the efficiency of the low-voltage automobile vacuum cleaner by replacing the existing DC motor with a switched reluctance motor (SRM, which has superior durability and efficiency.

  3. Study on Enhanceing Mechanisim and Policy on Energy Efficiency of Electrical Motor System in China

    Science.gov (United States)

    Liu, Ren; Zhao, Yuejin; Liu, Meng; Chen, Lili; Yang, Ming

    2017-12-01

    Motor is a kind of terminal energy-consumption equipment with the maximum power consumption in China every year; compared with international advanced level, the technical innovation of motor equipment, speed regulating system, drive system and automatic intelligent control technique in China still lag behind relatively; the standard technical service support system of motor system is not complete, the energy conserving transformation mode needs to be innovated, and the market development mechanism of motor industry is not perfect, etc. This paper analyzes the promotion mechanism and policy on energy efficiency of the motor system in China in recent years, studies the demonstration cases of successful promotion of high-efficiency motor, standard labeling, financial finance and tax policy, and puts forward suggestions on promotion of high-efficiency motor in China.

  4. Guidelines for calculating and enhancing detection efficiency of PIT tag interrogation systems

    Science.gov (United States)

    Connolly, Patrick J.

    2010-01-01

    With increasing use of passive integrated transponder (PIT) tags and reliance on stationary PIT tag interrogation systems to monitor fish populations, guidelines are offered to inform users how best to use limited funding and human resources to create functional systems that maximize a desired level of detection and precision. The estimators of detection efficiency and their variability as described by Connolly et al. (2008) are explored over a span of likely performance metrics. These estimators were developed to estimate detection efficiency without relying on a known number of fish passing the system. I present graphical displays of the results derived from these estimators to show the potential efficiency and precision to be gained by adding an array or by increasing the number of PIT-tagged fish expected to move past an interrogation system.

  5. Guidelines to indirectly measure and enhance detection efficiency of stationary PIT tag interrogation systems in streams

    Science.gov (United States)

    Connolly, Patrick J.; Wolf, Keith; O'Neal, Jennifer S.

    2010-01-01

    With increasing use of passive integrated transponder (PIT) tags and reliance on stationary PIT tag interrogation systems to monitor fish populations, guidelines are offered to inform users how best to use limited funding and human resources to create functional systems that maximize a desired level of detection and precision. The estimators of detection efficiency and their variability as described by Connolly et al. (2008) are explored over a span of likely performance metrics. These estimators were developed to estimate detection efficiency without relying on a known number of fish passing the system. I present graphical displays of the results derived from these estimators to show the potential efficiency and precision to be gained by adding an array or by increasing the number of PIT-tagged fish expected to move past an interrogation system.

  6. A novel vortex tube-based N2-expander liquefaction process for enhancing the energy efficiency of natural gas liquefaction

    Directory of Open Access Journals (Sweden)

    Qyyum Muhammad Abdul

    2017-01-01

    Full Text Available This research work unfolds a simple, safe, and environment-friendly energy efficient novel vortex tube-based natural gas liquefaction process (LNG. A vortex tube was introduced to the popular N2-expander liquefaction process to enhance the liquefaction efficiency. The process structure and condition were modified and optimized to take a potential advantage of the vortex tube on the natural gas liquefaction cycle. Two commercial simulators ANSYS® and Aspen HYSYS® were used to investigate the application of vortex tube in the refrigeration cycle of LNG process. The Computational fluid dynamics (CFD model was used to simulate the vortex tube with nitrogen (N2 as a working fluid. Subsequently, the results of the CFD model were embedded in the Aspen HYSYS® to validate the proposed LNG liquefaction process. The proposed natural gas liquefaction process was optimized using the knowledge-based optimization (KBO approach. The overall energy consumption was chosen as an objective function for optimization. The performance of the proposed liquefaction process was compared with the conventional N2-expander liquefaction process. The vortex tube-based LNG process showed a significant improvement of energy efficiency by 20% in comparison with the conventional N2-expander liquefaction process. This high energy efficiency was mainly due to the isentropic expansion of the vortex tube. It turned out that the high energy efficiency of vortex tube-based process is totally dependent on the refrigerant cold fraction, operating conditions as well as refrigerant cycle configurations.

  7. A novel vortex tube-based N2-expander liquefaction process for enhancing the energy efficiency of natural gas liquefaction

    Science.gov (United States)

    Qyyum, Muhammad Abdul; Wei, Feng; Hussain, Arif; Ali, Wahid; Sehee, Oh; Lee, Moonyong

    2017-11-01

    This research work unfolds a simple, safe, and environment-friendly energy efficient novel vortex tube-based natural gas liquefaction process (LNG). A vortex tube was introduced to the popular N2-expander liquefaction process to enhance the liquefaction efficiency. The process structure and condition were modified and optimized to take a potential advantage of the vortex tube on the natural gas liquefaction cycle. Two commercial simulators ANSYS® and Aspen HYSYS® were used to investigate the application of vortex tube in the refrigeration cycle of LNG process. The Computational fluid dynamics (CFD) model was used to simulate the vortex tube with nitrogen (N2) as a working fluid. Subsequently, the results of the CFD model were embedded in the Aspen HYSYS® to validate the proposed LNG liquefaction process. The proposed natural gas liquefaction process was optimized using the knowledge-based optimization (KBO) approach. The overall energy consumption was chosen as an objective function for optimization. The performance of the proposed liquefaction process was compared with the conventional N2-expander liquefaction process. The vortex tube-based LNG process showed a significant improvement of energy efficiency by 20% in comparison with the conventional N2-expander liquefaction process. This high energy efficiency was mainly due to the isentropic expansion of the vortex tube. It turned out that the high energy efficiency of vortex tube-based process is totally dependent on the refrigerant cold fraction, operating conditions as well as refrigerant cycle configurations.

  8. Novel bandgap grading technique for enhancing the limiting efficiency of solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Habib, S.E.-D.; Rafat, N.H. [Cairo Univ., Giza (Egypt). Faculty of Engineering

    1997-02-01

    The efficiency of solar cells is limited by radiative and/or Auger recombination losses. Radiative recombination can be reduced by limiting the escape angle of the re-emitted rays. Auger recombination can be reduced by limiting the cells` thickness. A novel technique for reducing the Auger recombination limit is proposed in this work. We show that bandgap grading can be effectively utilized to suppress the Auger recombination limit. The optimum bandgap grading profile that maximises the limiting efficiency for an idealized, one dimensional solar cell is hence calculated under AMO irradiation conditions. (author)

  9. Enhancing power cycle efficiency for a supercritical Brayton cycle power system using tunable supercritical gas mixtures

    Science.gov (United States)

    Wright, Steven A.; Pickard, Paul S.; Vernon, Milton E.; Radel, Ross F.

    2017-08-29

    Various technologies pertaining to tuning composition of a fluid mixture in a supercritical Brayton cycle power generation system are described herein. Compounds, such as Alkanes, are selectively added or removed from an operating fluid of the supercritical Brayton cycle power generation system to cause the critical temperature of the fluid to move up or down, depending upon environmental conditions. As efficiency of the supercritical Brayton cycle power generation system is substantially optimized when heat is rejected near the critical temperature of the fluid, dynamically modifying the critical temperature of the fluid based upon sensed environmental conditions improves efficiency of such a system.

  10. Dual Function Additives: A Small Molecule Crosslinker for Enhanced Efficiency and Stability in Organic Solar Cells

    KAUST Repository

    Rumer, Joseph W.

    2015-02-01

    A bis-azide-based small molecule crosslinker is synthesized and evaluated as both a stabilizing and efficiency-boosting additive in bulk heterojunction organic photovoltaic cells. Activated by a noninvasive and scalable solution processing technique, polymer:fullerene blends exhibit improved thermal stability with suppressed polymer skin formation at the cathode and frustrated fullerene aggregation on ageing, with initial efficiency increased from 6% to 7%. © 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Enhancing cognate target elution efficiency in gel-free chemical proteomics

    Directory of Open Access Journals (Sweden)

    Branka Radic-Sarikas

    2015-12-01

    Full Text Available Gel-free liquid chromatography mass spectrometry coupled to chemical proteomics is a powerful approach for characterizing cellular target profiles of small molecules. We have previously described a fast and efficient elution protocol; however, altered target profiles were observed. We hypothesised that elution conditions critically impact the effectiveness of disrupting drug-protein interactions. Thus, a number of elution conditions were systematically assessed with the aim of improving the recovery of all classes of proteins whilst maintaining compatibility with immunoblotting procedures. A double elution with formic acid combined with urea emerged as the most efficient and generically applicable elution method for chemical proteomics

  12. Passive magnetic separator integrated with microfluidic mixer: Demonstration of enhanced capture efficiency

    DEFF Research Database (Denmark)

    Lund-Olesen, Torsten; Bruus, Henrik; Hansen, Mikkel Fougt

    2006-01-01

    is the steep decrease of the magnetic force on the beads as a function of their distance to the magnetic structures. Our idea is to integrate the magnetic separator with a microfluidic mixer to ensure that all beads are brought close to the magnetic structures. We have fabricated a magnetic separator......In this paper, we present two results: (1) a new method for quantifying the efficiency of magnetic bead separators by magnetic measurements, and (2) a new idea for designing efficient magnetic bead separators. For microfluidic magnetic separators, a limiting factor for the capture of magnetic beads...

  13. Enhanced Efficiency of PTB7 : PC61BM Organic Solar Cells by Adding a Low Efficient Polymer Donor

    Directory of Open Access Journals (Sweden)

    Joana Farinhas

    2017-01-01

    Full Text Available Ternary blend polymer solar cells combining two electron-donor polymers, poly[4,8-bis[(2-ethylhexyloxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexylcarbonyl]thieno[3,4-b]thiophenediyl] (PTB7 and poly[2,5-bis(3-dodecylthiophen-2-ylthieno[3,2-b]thiophene] (pBTTT and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM, as electron-acceptor, were fabricated. The power conversion efficiency of the ternary cells was enhanced by 18%, with respect to the reference binary cells, for a blend composition with 25% (wt% of pBTTT in the polymers content. The optimized device performance was related to the blend morphology, nonrevealing pBTTT aggregates, and improved charge extraction within the device.

  14. Fast, accurate photon beam accelerator modeling using BEAMnrc: A systematic investigation of efficiency enhancing methods and cross-section data

    Energy Technology Data Exchange (ETDEWEB)

    Fragoso, Margarida; Kawrakow, Iwan; Faddegon, Bruce A.; Solberg, Timothy D.; Chetty, Indrin J. [Henry Ford Health System, Detroit, Michigan 48202 (United States); National Research Council of Canada, Ottawa, Ontario K1A OR6 (Canada); University of California, San Francisco, California 94143-0226 (United States); UT Southwestern Medical Center, Dallas, Texas 75390-9183 (United States); Henry Ford Health System, Detroit, Michigan 48202 (United States)

    2009-12-15

    In this work, an investigation of efficiency enhancing methods and cross-section data in the BEAMnrc Monte Carlo (MC) code system is presented. Additionally, BEAMnrc was compared with VMC++, another special-purpose MC code system that has recently been enhanced for the simulation of the entire treatment head. BEAMnrc and VMC++ were used to simulate a 6 MV photon beam from a Siemens Primus linear accelerator (linac) and phase space (PHSP) files were generated at 100 cm source-to-surface distance for the 10x10 and 40x40 cm{sup 2} field sizes. The BEAMnrc parameters/techniques under investigation were grouped by (i) photon and bremsstrahlung cross sections, (ii) approximate efficiency improving techniques (AEITs), (iii) variance reduction techniques (VRTs), and (iv) a VRT (bremsstrahlung photon splitting) in combination with an AEIT (charged particle range rejection). The BEAMnrc PHSP file obtained without the efficiency enhancing techniques under study or, when not possible, with their default values (e.g., EXACT algorithm for the boundary crossing algorithm) and with the default cross-section data (PEGS4 and Bethe-Heitler) was used as the ''base line'' for accuracy verification of the PHSP files generated from the different groups described previously. Subsequently, a selection of the PHSP files was used as input for DOSXYZnrc-based water phantom dose calculations, which were verified against measurements. The performance of the different VRTs and AEITs available in BEAMnrc and of VMC++ was specified by the relative efficiency, i.e., by the efficiency of the MC simulation relative to that of the BEAMnrc base-line calculation. The highest relative efficiencies were {approx}935 ({approx}111 min on a single 2.6 GHz processor) and {approx}200 ({approx}45 min on a single processor) for the 10x10 field size with 50 million histories and 40x40 cm{sup 2} field size with 100 million histories, respectively, using the VRT directional bremsstrahlung

  15. Siglec-1 initiates formation of the virus-containing compartment and enhances macrophage-to-T cell transmission of HIV-1.

    Directory of Open Access Journals (Sweden)

    Jason E Hammonds

    2017-01-01

    Full Text Available HIV-1 particles assemble and bud from the plasma membrane of infected T lymphocytes. Infected macrophages, in contrast, accumulate particles within an apparent intracellular compartment known as the virus-containing compartment or VCC. Many aspects of the formation and function of the VCC remain unclear. Here we demonstrate that VCC formation does not actually require infection of the macrophage, but can be reproduced through the exogenous addition of non-infectious virus-like particles or infectious virions to macrophage cultures. Particles were captured by Siglec-1, a prominent cell surface lectin that attaches to gangliosides on the lipid envelope of the virus. VCCs formed within infected macrophages were readily targeted by the addition of ganglioside-containing virus-like particles to the extracellular media. Depletion of Siglec-1 from the macrophage or depletion of gangliosides from viral particles prevented particle uptake into the VCC and resulted in substantial reductions of VCC volume. Furthermore, Siglec-1-mediated virion capture and subsequent VCC formation was required for efficient trans-infection of autologous T cells. Our results help to define the nature of this intracellular compartment, arguing that it is a compartment formed by particle uptake from the periphery, and that this compartment can readily transmit virus to target T lymphocytes. Inhibiting or eliminating the VCC may be an important component of strategies to reduce HIV transmission and to eradicate HIV reservoirs.

  16. Hydrogen and nitrogen codoping of anatase TiO2for efficiency enhancement in organic solar cells.

    Science.gov (United States)

    Vasilopoulou, Maria; Kelaidis, Nikolaos; Polydorou, Ermioni; Soultati, Anastasia; Davazoglou, Dimitris; Argitis, Panagiotis; Papadimitropoulos, Giorgos; Tsikritzis, Dimitris; Kennou, Stella; Auras, Florian; Georgiadou, Dimitra G; Christopoulos, Stavros-Richard G; Chroneos, Alexander

    2017-12-19

    TiO 2 has high chemical stability, strong catalytic activity and is an electron transport material in organic solar cells. However, the presence of trap states near the band edges of TiO 2 arising from defects at grain boundaries significantly affects the efficiency of organic solar cells. To become an efficient electron transport material for organic photovoltaics and related devices, such as perovskite solar cells and photocatalytic devices, it is important to tailor its band edges via doping. Nitrogen p-type doping has attracted considerable attention in enhancing the photocatalytic efficiency of TiO 2 under visible light irradiation while hydrogen n-type doping increases its electron conductivity. DFT calculations in TiO 2 provide evidence that nitrogen and hydrogen can be incorporated in interstitial sites and possibly form N i H i , N i H O and N Ti H i defects. The experimental results indicate that N i H i defects are most likely formed and these defects do not introduce deep level states. Furthermore, we show that the efficiency of P3HT:IC 60 BA-based organic photovoltaic devices is enhanced when using hydrogen-doping and nitrogen/hydrogen codoping of TiO 2 , both boosting the material n-type conductivity, with maximum power conversion efficiency reaching values of 6.51% and 6.58%, respectively, which are much higher than those of the cells with the as-deposited (4.87%) and nitrogen-doped TiO 2 (4.46%).

  17. Effective and efficient learning in the operating theater with intraoperative video-enhanced surgical procedure training

    NARCIS (Netherlands)

    van Det, M.J.; Meijerink, W.J.; Hoff, C.; Middel, B.; Pierie, J.P.

    INtraoperative Video Enhanced Surgical procedure Training (INVEST) is a new training method designed to improve the transition from basic skills training in a skills lab to procedural training in the operating theater. Traditionally, the master-apprentice model (MAM) is used for procedural training

  18. Enhanced transfection efficiency and reduced cytotoxicity of novel lipid-polymer hybrid nanoplexes

    DEFF Research Database (Denmark)

    Jain, Sanyog; Kumar, Sandeep; Agrawal, Ashish Kumar

    2013-01-01

    The present study reports the development, characterization, and evaluation of novel polyelectrolytes stabilized lipoplexes as a nonviral vector for gene delivery. In order to achieve the advantage of both DOTAP (1,2-dioleoyl-3-trimethylammonium propane) and PEI (high transfection efficiency...

  19. Lubricant Formulations to Enhance Engine Efficiency in Modern Internal Combustion Engines

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Wai [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Wong, Victor [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Plumley, Michael [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Martins, Tomas [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Gu, Grace [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Tracy, Ian [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Molewyk, Mark [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Park, Soo Youl [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2017-04-19

    The research program presented aimed to investigate, develop, and demonstrate low-friction, environmentally-friendly and commercially-feasible lubricant formulations that would significantly improve the mechanical efficiency of modern engines without incurring increased wear, emissions or deterioration of the emission-aftertreatment system.

  20. Analysis Platform for Energy Efficiency Enhancement in Hybrid and Full Electric Vehicles

    Directory of Open Access Journals (Sweden)

    NICOLAICA, M.-O.

    2016-02-01

    Full Text Available The current paper presents a new virtual analysis method that is applied both on hybrid and electric vehicle architectures with the purpose of contributing to the improvement of energy efficiency. The study is based on Matlab modeling and simulation. A set of parameters are considered in order to assess the system performance. The benefit is given by the comparative overview obtained after the completed analysis. The effectiveness of the analysis method is confirmed by a sequence of simulation results combined in several case studies. The impulse of the research is given by the fact that the automotive market is focusing on wider simulation techniques and better control strategies that lead to more efficient vehicles. Applying the proposed method during design would improve the battery management and controls strategy. The advantage of this method is that the system behavior with regards to energy efficiency can be evaluated from an early concept phase. The results contribute to the actual necessity of driving more efficient and more environmental friendly vehicles.

  1. Efficiency enhancement of dye-sensitized solar cells with addition of ...

    Indian Academy of Sciences (India)

    The dependence of different photovoltaic performance parameters (\\oc, sc, , ) of DSC upon temperature has been studied over a 30–120°C range and only a small decrease in conversion efficiency has been observed. The electrolyte containing binary additives (DMAP and CEMI) shows best cell performance up to ...

  2. An ME-PC Enhanced HDMR Method for Efficient Statistical Analysis of Multiconductor Transmission Line Networks

    KAUST Repository

    Yucel, Abdulkadir C.

    2015-05-05

    An efficient method for statistically characterizing multiconductor transmission line (MTL) networks subject to a large number of manufacturing uncertainties is presented. The proposed method achieves its efficiency by leveraging a high-dimensional model representation (HDMR) technique that approximates observables (quantities of interest in MTL networks, such as voltages/currents on mission-critical circuits) in terms of iteratively constructed component functions of only the most significant random variables (parameters that characterize the uncertainties in MTL networks, such as conductor locations and widths, and lumped element values). The efficiency of the proposed scheme is further increased using a multielement probabilistic collocation (ME-PC) method to compute the component functions of the HDMR. The ME-PC method makes use of generalized polynomial chaos (gPC) expansions to approximate the component functions, where the expansion coefficients are expressed in terms of integrals of the observable over the random domain. These integrals are numerically evaluated and the observable values at the quadrature/collocation points are computed using a fast deterministic simulator. The proposed method is capable of producing accurate statistical information pertinent to an observable that is rapidly varying across a high-dimensional random domain at a computational cost that is significantly lower than that of gPC or Monte Carlo methods. The applicability, efficiency, and accuracy of the method are demonstrated via statistical characterization of frequency-domain voltages in parallel wire, interconnect, and antenna corporate feed networks.

  3. Efficiency enhancement using voltage biasing for ferroelectric polarization in dye-sensitized solar cells

    Science.gov (United States)

    Kim, Sangmo; Song, Myoung Geun; Bark, Chung Wung

    2018-01-01

    Dye-sensitized solar cells (DSSCs) are one of the most promising third generation solar cells that have been extensively researched over the past decade as alternative to silicon-based solar cells, due to their low production cost and high energy-conversion efficiency. In general, a DSSC consists of a transparent electrode, a counter electrode, and an electrolyte such as dye. To achieve high power-conversion efficiency in cells, many research groups have focused their efforts on developing efficient dyes for liquid electrolytes. In this work, we report on the photovoltaic properties of DSSCs fabricated using a mixture of TiO2 with nanosized Fe-doped bismuth lanthanum titanate (nFe-BLT) powder). Firstly, nFe-BLT powders were prepared using a high-energy ball milling process and then, TiO2 and nFe-BLT powders were stoichiometrically blended. Direct current (DC) bias of 20 MV/m was applied to lab-made DSSCs. With the optimal concentration of nFe-BLT doped in the electrode, their light-to-electricity conversion efficiency could be improved by ∼64% compared with DSSCs where no DC bias was applied.

  4. Enhanced energy efficiency in waste water treatment plants; Steigerung der Energieeffizienz auf kommunalen Klaeranlagen

    Energy Technology Data Exchange (ETDEWEB)

    Haberkern, Bernd; Maier, Werner; Schneider, Ursula [iat - Ingenieurberatung fuer Abwassertechnik, Darmstadt und Stuttgart, Darmstadt (Germany)

    2008-03-15

    In order to implement the requests of EU-IPCC-directive in a new decree for waste water treatment in Germany, best available techniques have to be defined to optimize energy efficiency in waste water treatment plants (WWTP). Therefore energy efficiency was investigated for common treatment processes and new technologies like membrane filtration, co-digestion or phosphorus recycling. In addition, the occurrence of different technologies for waste water and sludge treatment was evaluated for different size ranges of treatment plants (in population equivalents, PE) nationwide in Germany. The definition of actual and aimed values for specific energy consumption (in kWh/(PE.a)) allowed to calculate the potential energy savings in WWTP and the additional consumption due to new processes on a national level. Under consideration of the reciprocations between optimized energy consumption in WWTP and operation practice, toe-holds to increase energy efficiency according to their relevancy for the national balance could be listed. Case studies prove the feasibility of the investigated techniques and allow proposals for minimum requirements in legal regulation concerning energy efficiency in WWTP. (orig.)

  5. Preparation of Fiber Based Binder Materials to Enhance the Gas Adsorption Efficiency of Carbon Air Filter.

    Science.gov (United States)

    Lim, Tae Hwan; Choi, Jeong Rak; Lim, Dae Young; Lee, So Hee; Yeo, Sang Young

    2015-10-01

    Fiber binder adapted carbon air filter is prepared to increase gas adsorption efficiency and environmental stability. The filter prevents harmful gases, as well as particle dusts in the air from entering the body when a human inhales. The basic structure of carbon air filter is composed of spunbond/meltblown/activated carbon/bottom substrate. Activated carbons and meltblown layer are adapted to increase gas adsorption and dust filtration efficiency, respectively. Liquid type adhesive is used in the conventional carbon air filter as a binder material between activated carbons and other layers. However, it is thought that the liquid binder is not an ideal material with respect to its bonding strength and liquid flow behavior that reduce gas adsorption efficiency. To overcome these disadvantages, fiber type binder is introduced in our study. It is confirmed that fiber type binder adapted air filter media show higher strip strength, and their gas adsorption efficiencies are measured over 42% during 60 sec. These values are higher than those of conventional filter. Although the differential pressure of fiber binder adapted air filter is relatively high compared to the conventional one, short fibers have a good potential as a binder materials of activated carbon based air filter.

  6. Enhancing the efficiency of producing energy from biomass; Effizienzsteigerung bei der energetischen Biomassenutzung

    Energy Technology Data Exchange (ETDEWEB)

    Quicker, P.; Hamatschek, E.; Faulstich, M. [ATZ Entwicklungszentrum, Sulzbach-Rosenberg (Germany); Greiff, K. [Lehrtstuhl fuer Technologie Biologischer Rohstoffe, Freising (Germany). Standort Weihenstephan

    2006-07-01

    There are various ways of increasing the efficiency of producing energy from biomass. From the viewpoint of the operator efficiency improvements should also always lead to an improvement of profitability. In this respect the amendment of the Renewable Energy Law has set the course in the right direction. In its present version the law grants extra remuneration not only for the development of new potentials but also for the installation of new, more efficient processes and for cogeneration. Unfortunately this preferential treatment only applies for vegetable raw materials. By contrast, biogenic residues only play a minor role in the system created by the Renewable Energy Law, and some biogenic wastes such as sewage sludge or the biogenic fraction of household waste are not considered at all. There is still an enormous energy potential waiting to be tapped not only through technical optimisation, various options for which are discussed in the present paper, but also through political measures. If the principles of the Renewable Energy Law were also applied to the waste economy, this could put a swift end to such energy destruction methods as composting, mechanical biological waste treatment or waste incineration, the latter of which has an overall efficiency of no more than 10%.

  7. Energy efficiency enhancements for semiconductors, communications, sensors and software achieved in cool silicon cluster project

    Science.gov (United States)

    Ellinger, Frank; Mikolajick, Thomas; Fettweis, Gerhard; Hentschel, Dieter; Kolodinski, Sabine; Warnecke, Helmut; Reppe, Thomas; Tzschoppe, Christoph; Dohl, Jan; Carta, Corrado; Fritsche, David; Tretter, Gregor; Wiatr, Maciej; Detlef Kronholz, Stefan; Mikalo, Ricardo Pablo; Heinrich, Harald; Paulo, Robert; Wolf, Robert; Hübner, Johannes; Waltsgott, Johannes; Meißner, Klaus; Richter, Robert; Michler, Oliver; Bausinger, Markus; Mehlich, Heiko; Hahmann, Martin; Möller, Henning; Wiemer, Maik; Holland, Hans-Jürgen; Gärtner, Roberto; Schubert, Stefan; Richter, Alexander; Strobel, Axel; Fehske, Albrecht; Cech, Sebastian; Aßmann, Uwe; Pawlak, Andreas; Schröter, Michael; Finger, Wolfgang; Schumann, Stefan; Höppner, Sebastian; Walter, Dennis; Eisenreich, Holger; Schüffny, René

    2013-07-01

    An overview about the German cluster project Cool Silicon aiming at increasing the energy efficiency for semiconductors, communications, sensors and software is presented. Examples for achievements are: 1000 times reduced gate leakage in transistors using high-fc (HKMG) materials compared to conventional poly-gate (SiON) devices at the same technology node; 700 V transistors integrated in standard 0.35 μm CMOS; solar cell efficiencies above 19% at Commerce applications; processors and corresponding data links with 40% and 70% energy savings, respectively, by adaption of clock frequency and supply voltage in less than 20 ns; clock generator chip with tunable frequency from 83-666 MHz and 0.62-1.6 mW dc power; 90 Gb/s on-chip link over 6 mm and efficiency of 174 fJ/mm; dynamic biasing system doubling efficiency in power amplifiers; 60 GHz BiCMOS frontends with dc power to bandwidth ratio of 0.17 mW/MHz; driver assistance systems reducing energy consumption by 10% in cars Contribution to the Topical Issue “International Semiconductor Conference Dresden-Grenoble - ISCDG 2012”, Edited by Gérard Ghibaudo, Francis Balestra and Simon Deleonibus.

  8. A systematic review of prospective memory in HIV disease: from the laboratory to daily life.

    Science.gov (United States)

    Avci, Gunes; Sheppard, David P; Tierney, Savanna M; Kordovski, Victoria M; Sullivan, Kelli L; Woods, Steven Paul

    2017-09-27

    Prospective memory (PM) is described as the capacity to form and maintain an intention that is executed in response to a specific cue. Neural injury and associated neurocognitive disorders are common among persons living with HIV disease, who might therefore be susceptible to impairment in PM. This literature review utilized a structured qualitative approach to summarize and evaluate our current understanding of PM functioning in people living with HIV disease. 33 studies of PM in HIV+ persons met criteria for inclusion. Findings showed that HIV is associated with moderate deficits in PM, which appear to be largely independent of commonly observed comorbid factors. The pattern of PM deficits reveals dysregulation of strategic processes that is consistent with the frontal systems pathology and associated executive dysfunction that characterizes HIV-associated neural injury. The literature also suggests that HIV-associated PM deficits present a strong risk of concurrent problems in a wide range of health behaviors (e.g. medication non-adherence) and activities of daily living (e.g. employment). Early attempts to improve PM in HIV disease have revealed that supporting strategic processes might be effective for some individuals. HIV-associated PM deficits are common and exert a significant adverse effect on the daily lives and health of infected persons. Much work remains to be done to understand the cognitive architecture of HIV-associated PM deficits and the most efficient means to enhance PM functioning and improve health outcomes in persons living with HIV.

  9. A Significant Increase of RNAi Efficiency in Human Cells by the CMV Enhancer with a tRNAlys Promoter

    Directory of Open Access Journals (Sweden)

    Ma Weiwei

    2009-01-01

    Full Text Available RNA interference (RNAi is the process of mRNA degradation induced by double-stranded RNA in a sequence-specific manner. Different types of promoters, such as U6, H1, tRNA, and CMV, have been used to control the inhibitory effect of RNAi expression vectors. In the present study, we constructed two shRNA expression vectors, respectively, controlled by tRNAlys and CMV enhancer-tRNAlys promoters. Compared to the vectors with tRNAlys or U6 promoter, the vector with a CMV enhancer-tRNAlys promoter silenced pokemon more efficiently on both the mRNA and the protein levels. Meanwhile, the silencing of pokemon inhibited the proliferation of MCF7 cells, but the induction of apoptosis of MCF7 cells was not observed. We conclude that the CMV enhancer-tRNAlys promoter may be a powerful tool in driving intracellular expression of shRNA which can efficiently silence targeted gene.

  10. A Significant Increase of RNAi Efficiency in Human Cells by the CMV Enhancer with a tRNAlys Promoter

    Science.gov (United States)

    Weiwei, Ma; Zhenhua, Xie; Feng, Liu; Hang, Ning; Yuyang, Jiang

    2009-01-01

    RNA interference (RNAi) is the process of mRNA degradation induced by double-stranded RNA in a sequence-specific manner. Different types of promoters, such as U6, H1, tRNA, and CMV, have been used to control the inhibitory effect of RNAi expression vectors. In the present study, we constructed two shRNA expression vectors, respectively, controlled by tRNAlys and CMV enhancer-tRNAlys promoters. Compared to the vectors with tRNAlys or U6 promoter, the vector with a CMV enhancer-tRNAlys promoter silenced pokemon more efficiently on both the mRNA and the protein levels. Meanwhile, the silencing of pokemon inhibited the proliferation of MCF7 cells, but the induction of apoptosis of MCF7 cells was not observed. We conclude that the CMV enhancer-tRNAlys promoter may be a powerful tool in driving intracellular expression of shRNA which can efficiently silence targeted gene. PMID:19859553

  11. Enhanced power conversion efficiency in InGaN-based solar cells via graded composition multiple quantum wells.

    Science.gov (United States)

    Tsai, Yu-Lin; Wang, Sheng-Wen; Huang, Jhih-Kai; Hsu, Lung-Hsing; Chiu, Ching-Hsueh; Lee, Po-Tsung; Yu, Peichen; Lin, Chien-Chung; Kuo, Hao-Chung

    2015-11-30

    This work demonstrates the enhanced power conversion efficiency (PCE) in InGaN/GaN multiple quantum well (MQWs) solar cells with gradually decreasing indium composition in quantum wells (GQWs) toward p-GaN as absorber. The GQW can improve the fill factor from 42% to 62% and enhance the short current density from 0.8 mA/cm2 to 0.92 mA/cm2, as compares to the typical MQW solar cells. As a result, the PCE is boosted from 0.63% to 1.11% under AM1.5G illumination. Based on simulation and experimental results, the enhanced PCE can be attributed to the improved carrier collection in GQW caused by the reduction of potential barriers and piezoelectric polarization induced fields near the p-GaN layer. The presented concept paves a way toward highly efficient InGaN-based solar cells and other GaN-related MQW devices.

  12. Hardware-efficient signal generation of layered/enhanced ACO-OFDM for short-haul fiber-optic links.

    Science.gov (United States)

    Wang, Qibing; Song, Binhuang; Corcoran, Bill; Boland, David; Zhu, Chen; Zhuang, Leimeng; Lowery, Arthur J

    2017-06-12

    Layered/enhanced ACO-OFDM is a promising candidate for intensity modulation and direct-detection based short-haul fiber-optic links due to its both power and spectral efficiency. In this paper, we firstly demonstrate a hardware-efficient real-time 9.375 Gb/s QPSK-encoded layered/enhanced asymmetrical clipped optical OFDM (L/E-ACO-OFDM) transmitter using a Virtex-6 FPGA. This L/E-ACO-OFDM signal is successfully transmitted over 20-km uncompensated standard single-mode fiber (S-SMF) using a directly modulated laser. Several methods are explored to reduce the FPGA's logic resource utilization by taking advantage of the L/E-ACO-OFDM's signal characteristics. We show that the logic resource occupation of L/E-ACO-OFDM transmitter is almost the same as that of DC-biased OFDM transmitter when they achieve the same spectral efficiency, proving its great potential to be used in a real-time short-haul optical transmission link.

  13. A transgenic approach to enhance phosphorus use efficiency in crops as part of a comprehensive strategy for sustainable agriculture.

    Science.gov (United States)

    Gaxiola, Roberto A; Edwards, Mark; Elser, James J

    2011-08-01

    Concerns about phosphorus (P) sustainability in agriculture arise not only from the potential of P scarcity but also from the known effects of agricultural P use beyond the field, i.e., eutrophication leading to dead zones in lakes, rivers and coastal oceans due to runoffs from fertilized fields. Plants possess a large number of adaptive responses to P(i) (orthophosphate) limitation that provide potential raw materials to enhance P(i) scavenging abilities of crop plants. Understanding and engineering these adaptive responses to increase the efficiency of crop capture of natural and fertilizer P(i) in soils is one way to optimize P(i) use efficiency (PUE) and, together with other approaches, help to meet the P sustainability challenge in agriculture. Research on the molecular and physiological basis of P(i) uptake is facilitating the generation of plants with enhanced P(i) use efficiency by genetic engineering. Here we describe work done in this direction with emphasis on the up-regulation of plant proton-translocating pyrophosphatases (H(+)-PPases). Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Enhanced photocatalytic efficiencies over A- or B-sites substituted LaFeO3/silica fiber composites

    Science.gov (United States)

    Zhang, Li; Xu, Tianhong; Guo, Qianyun; Ling, Ze; Zou, Rongjiang; Wu, Qiang

    2017-11-01

    Novel A- or B-sites substituted LaFeO3/silica fiber (SF) composites were prepared via a facile and efficient carbon nanofibers (CNFs) template-assisted alcohol-thermal route. The resulting samples were characterized by X-Ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET) apparatus, and ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy. Furthermore, their photocatalytic activities were evaluated by visible-light photocatalytic degradation of methylene blue (MB). Compared with powder LaFeO3, the obtained A- or B-sites substituted LaFeO3/SF composites showed enhanced degradation efficiencies to MB dyes under the identical conditions. Good stability was also observed in the cyclic runs for the degradation of MB. The enhanced photocatalytic performance should be relent with the following two factors: 1) the unique morphology and structure of A- or B-sites substituted LaFeO3/SF composites, and 2) the contribution of the secondary element doping either in A- or B-sites of LaFeO3/SF. The synthetic procedure is simple and could be applicable to other efficient and inexpensive photocatalytic materials.

  15. Remarkable Charge Separation and Photocatalytic Efficiency Enhancement through Interconnection of TiO2 Nanoparticles by Hydrothermal Treatment.

    Science.gov (United States)

    Ide, Yusuke; Inami, Nozomu; Hattori, Hideya; Saito, Kanji; Sohmiya, Minoru; Tsunoji, Nao; Komaguchi, Kenji; Sano, Tsuneji; Bando, Yoshio; Golberg, Dmitri; Sugahara, Yoshiyuki

    2016-03-07

    Although tremendous effort has been directed to synthesizing advanced TiO2 , it remains difficult to obtain TiO2 exhibiting a photocatalytic efficiency higher than that of P25, a benchmark photocatalyst. P25 is composed of anatase, rutile, and amorphous TiO2 particles, and photoexcited electron transfer and subsequent charge separation at the anatase-rutile particle interfaces explain its high photocatalytic efficiency. Herein, we report on a facile and rational hydrothermal treatment of P25 to selectively convert the amorphous component into crystalline TiO2 , which is deposited between the original anatase and rutile particles to increase the particle interfaces and thus enhance charge separation. This process produces a new TiO2 exhibiting a considerably enhanced photocatalytic efficiency. This method of synthesizing this TiO2 , inspired by a recently burgeoning zeolite design, promises to make TiO2 applications more feasible and effective. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Enhancing light extraction efficiency of polymer light-emitting diodes with a 12-fold photonic quasi crystal.

    Science.gov (United States)

    Lin, Jian Hung; Chang, Wei Lang; Lin, Hung-Yi; Chou, Ta-Hsin; Kan, Hung-Chih; Hsu, Chia Chen

    2013-09-23

    This work demonstrates the enhancement of light extraction of polymer light-emitting diodes (PLEDs) by incorporating a 12-fold photonic quasi crystal (PQC) in the device structure. Multi-exposure two-beam interference technique combined with inductively coupled plasma etching was employed to pattern a 12-fold PQC structure on the ITO film on a glass substrate of the diode. The air-hole coverage (AHC) and etching depth dependences of the light emitting performance of the 12-fold PQC patterned PLEDs were investigated. For AHC within the range between 6.4% and 32.3%, a nearly constant enhancement of the luminance efficiency of the PQC PLEDs was observed. On the other hand, the light emitting performance of the PQC PLEDs is very sensitive to the etching depth. The photoluminescence intensity of the PQC PLEDs increases monotonically with the etching depth. In contrast, the electro luminance efficiency shows a non-monotonic dependence on etching depth with a maximum occurring at 55 nm etching depth. The maximum improvement of luminance efficiency of the 12-fold PQC PLEDs reaches nearly 95% compared with an un-patterned PLED at an injection current of 110 mA.

  17. Efficient visible-light photocatalytic and enhanced photocorrosion inhibition of Ag2WO4 decorated MoS2 nanosheets

    Science.gov (United States)

    Thangavel, Sakthivel; Thangavel, Srinivas; Raghavan, Nivea; Alagu, Raja; Venugopal, Gunasekaran

    2017-11-01

    The use of two-dimensional nanomaterials as co-catalysts in the photodegradation of toxic compounds using light irradiation is an attractive ecofriendly process. In this study, we prepared a novel MoS2/Ag2WO4 nanohybrid via a one-step hydrothermal approach and the photocatalytic properties were investigated by the degradation of methyl-orange under stimulated irradiation. The nanohybrid exhibits enhanced efficiency in dye degradation compared to the bare Ag2WO4 nanorods; the same has been evidently confirmed with UV-visible spectra and total organic carbon removal analysis. The pseudo-first order rate constant of the nanohybrid is nearly 1.8 fold higher than that of the bare Ag2WO4 nanorods. With the aid of classical radical quenching and photoluminescence spectral analysis, a reasonable mechanism has been derived for the addition of MoS2 to nanohybrids to enhance the photocatalytic efficiency. MoS2 prevents photocorrosion of Ag2WO4 and also diminishes the number of photogenerated electron-hole recombination. Our findings could provide new insights in understanding the mechanism of the MoS2/Ag2WO4 nanohybrid as an efficient photocatalyst suitable for waste-water treatment and remedial applications.

  18. Differential activity of candidate microbicides against early steps of HIV-1 infection upon complement virus opsonization

    Directory of Open Access Journals (Sweden)

    Bell Thomas W

    2010-06-01

    Full Text Available Abstract Background HIV-1 in genital secretions may be opsonized by several molecules including complement components. Opsonized HIV-1 by complement enhances the infection of various mucosal target cells, such as dendritic cells (DC and epithelial cells. Results We herein evaluated the effect of HIV-1 complement opsonization on microbicide candidates' activity, by using three in vitro mucosal models: CCR5-tropic HIV-1JR-CSF transcytosis through epithelial cells, HIV-1JR-CSF attachment on immature monocyte-derived dendritic cells (iMDDC, and infectivity of iMDDC by CCR5-tropic HIV-1BaL and CXCR4-tropic HIV-1NDK. A panel of 10 microbicide candidates [T20, CADA, lectines HHA & GNA, PVAS, human lactoferrin, and monoclonal antibodies IgG1B12, 12G5, 2G12 and 2F5], were investigated using cell-free unopsonized or opsonized HIV-1 by complements. Only HHA and PVAS were able to inhibit HIV trancytosis. Upon opsonization, transcytosis was affected only by HHA, HIV-1 adsorption on iMDDC by four molecules (lactoferrin, IgG1B12, IgG2G5, IgG2G12, and replication in iMDDC of HIV-1BaL by five molecules (lactoferrin, CADA, T20, IgG1B12, IgG2F5 and of HIV-1NDK by two molecules (lactoferrin, IgG12G5. Conclusion These observations demonstrate that HIV-1 opsonization by complements may modulate in vitro the efficiency of candidate microbicides to inhibit HIV-1 infection of mucosal target cells, as well as its crossing through mucosa.

  19. Performance comparison of the 4th generation Bio-Rad Laboratories GS HIV Combo Ag/Ab EIA on the EVOLIS™ automated system versus Abbott ARCHITECT HIV Ag/Ab Combo, Ortho Anti-HIV 1+2 EIA on Vitros ECi and Siemens HIV-1/O/2 enhanced on Advia Centaur.

    Science.gov (United States)

    Mitchell, Elizabeth O; Stewart, Greg; Bajzik, Olivier; Ferret, Mathieu; Bentsen, Christopher; Shriver, M Kathleen

    2013-12-01

    A multisite study was conducted to evaluate the performance of the Bio-Rad 4th generation GS HIV Combo Ag/Ab EIA versus Abbott 4th generation ARCHITECT HIV Ag/Ab Combo. The performance of two 3rd generation EIAs, Ortho Diagnostics Anti-HIV 1+2 EIA and Siemens HIV 1/O/2 was also evaluated. Study objective was comparison of analytical HIV-1 p24 antigen detection, sensitivity in HIV-1 seroconversion panels, specificity in blood donors and two HIV false reactive panels. Analytical sensitivity was evaluated with International HIV-1 p24 antigen standards, the AFFSAPS (pg/mL) and WHO 90/636 (IU/mL) standards; sensitivity in acute infection was compared on 55 seroconversion samples, and specificity was evaluated on 1000 negative blood donors and two false reactive panels. GS HIV Combo Ag/Ab demonstrated better analytical HIV antigen sensitivity compared to ARCHITECT HIV Ag/Ab Combo: 0.41 IU/mL versus 1.2 IU/mL (WHO) and 12.7 pg/mL versus 20.1 pg/mL (AFSSAPS); GS HIV Combo Ag/Ab EIA also demonstrated slightly better specificity compared to ARCHITECT HIV Ag/Ab Combo (100% versus 99.7%). The 4th generation HIV Combo tests detected seroconversion 7-11 days earlier than the 3rd generation HIV antibody only EIAs. Both 4th generation immunoassays demonstrated excellent performance in sensitivity, with the reduction of the serological window period (7-11 days earlier detection than the 3rd generation HIV tests). However, GS HIV Combo Ag/Ab demonstrated improved HIV antigen analytical sensitivity and slightly better specificity when compared to ARCHITECT HIV Ag/Ab Combo assay, with higher positive predictive values (PPV) for low prevalence populations. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. The evaluation of the JEWEL project: an innovative economic enhancement and HIV prevention intervention study targeting drug using women involved in prostitution.

    Science.gov (United States)

    Sherman, S G; German, D; Cheng, Y; Marks, M; Bailey-Kloche, M

    2006-01-01

    The JEWEL (Jewellery Education for Women Empowering Their Lives) pilot study examined the efficacy of an economic empowerment and HIV prevention intervention targeting illicit drug-using women (n=50) who were involved in prostitution in Baltimore, Maryland. The intervention was comprised of six 2-hour sessions that taught HIV prevention risk reduction and the making, marketing and selling of jewellery. Bivariate comparisons examined behaviour change pre- and 3-months post-intervention. The intervention's effect on the change in the number of sex trade partners from baseline to follow-up was explored with multiple linear regression. Participants were 62.0% African American, 5.0% were currently employed, and the median age was 39 years old (Inter Quartile Range [IQR]: 34-45). Women attended an average of six (IQR: 4.5-6.0) sessions. The women sold over $7,000 worth of jewellery in eleven sales. In comparing self-reported risk behaviours pre and 3-month post intervention participation, we found significant reductions in: receiving drugs or money for sex (100% versus 71.0%, p5.0%, p=0.003); the amount of money spent on drugs daily (US$52.57 versus US$46.71, p = 0.01); and daily crack use (27.3% versus 13.1.0%, p = 0.014). In the presence of other variables in a multivariate linear model, income from the jewelry sale was associated with a reduction in the number of sex trade partners at follow-up. The pilot indicated effectiveness of a novel, HIV prevention, economic enhancement intervention upon HIV sexual risk behaviours and drug utilization patterns.

  1. "+CLICK": pilot of a web-based training program to enhance ART adherence among HIV-positive youth.

    Science.gov (United States)

    Shegog, Ross; Markham, Christine M; Leonard, Amy D; Bui, Thanh C; Paul, Mary E

    2012-01-01

    Youth account for almost half of all new HIV infections in the United States. Adherence to antiretroviral treatme