"Spider"-shaped porphyrins with conjugated pyridyl anchoring groups as efficient sensitizers for dye-sensitized solar cells.

PubMed

Stangel, Christina; Bagaki, Anthi; Angaridis, Panagiotis A; Charalambidis, Georgios; Sharma, Ganesh D; Coutsolelos, Athanasios G

2014-11-17

Two novel "spider-shaped" porphyrins, meso-tetraaryl-substituted 1PV-Por and zinc-metalated 1PV-Zn-Por, bearing four oligo(p-phenylenevinylene) (oPPV) pyridyl groups with long dodecyloxy chains on the phenyl groups, have been synthesized. The presence of four pyridyl groups in both porphyrins, which allow them to act as anchoring groups upon coordination to various Lewis acid sites, the conjugated oPPV bridges, which offer the possibility of electronic communication between the porphyrin core and the pyridyl groups, and the dodecyloxy groups, which offer the advantage of high solubility in a variety of organic solvents of different polarities and could prevent porphyrin aggregation, renders porphyrins 1PV-Por and 1PV-Zn-Por very promising sensitizers for dye-sensitized solar cells (DSSCs). Photophysical measurements, together with electrochemistry experiments and density functional theory calculations, suggest that both porphyrins have frontier molecular orbital energy levels that favor electron injection and dye regeneration in DSSCs. Solar cells sensitized by 1PV-Por and 1PV-Zn-Por were fabricated, and it was found that they show power conversion efficiencies (PCEs) of 3.28 and 5.12%, respectively. Photovoltaic measurements (J-V curves) together with incident photon-to-electron conversion efficiency spectra of the two cells reveal that the higher PCE value of the DSSC based on 1PV-Zn-Por is ascribed to higher short-circuit current (Jsc), open-circuit voltage (Voc), and dye loading values. Emission spectra and electrochemistry experiments suggest a greater driving force for injection of the photogenerated electrons into the TiO2 conduction band for 1PV-Zn-Por rather than its free-base analogue. Furthermore, electrochemical impedance spectroscopy measurements prove that the utilization of 1PV-Zn-Por as a sensitizer offers a high charge recombination resistance and, therefore, leads to a longer electron lifetime.

Photovoltaic-Model-Based Solar Irradiance Estimators: Performance Comparison and Application to Maximum Power Forecasting

NASA Astrophysics Data System (ADS)

Scolari, Enrica; Sossan, Fabrizio; Paolone, Mario

2018-01-01

Due to the increasing proportion of distributed photovoltaic (PV) production in the generation mix, the knowledge of the PV generation capacity has become a key factor. In this work, we propose to compute the PV plant maximum power starting from the indirectly-estimated irradiance. Three estimators are compared in terms of i) ability to compute the PV plant maximum power, ii) bandwidth and iii) robustness against measurements noise. The approaches rely on measurements of the DC voltage, current, and cell temperature and on a model of the PV array. We show that the considered methods can accurately reconstruct the PV maximum generation even during curtailment periods, i.e. when the measured PV power is not representative of the maximum potential of the PV array. Performance evaluation is carried out by using a dedicated experimental setup on a 14.3 kWp rooftop PV installation. Results also proved that the analyzed methods can outperform pyranometer-based estimations, with a less complex sensing system. We show how the obtained PV maximum power values can be applied to train time series-based solar maximum power forecasting techniques. This is beneficial when the measured power values, commonly used as training, are not representative of the maximum PV potential.

Bifacial aspects of industrial n-Pasha solar cells

NASA Astrophysics Data System (ADS)

Van Aken, Bas B.; Tool, Kees; Kossen, Eric J.; Carr, Anna J.; Janssen, Gaby J. M.; Newman, Bonna K.; Romijn, Ingrid G.

2017-08-01

Bifacial photovoltaic (PV) modules make optimal use of diffuse and ground-reflected light. The gain in energy yield depends on both the local climatic conditions and the PV system layout. These determine the additional irradiance on the rear of the PV panels. The rear response of the (laminated) solar cell(s) determines how much additional energy this rear irradiance generates. Based on our experiments and simulations, the main parameters that determine the bifaciality factor of solar cells with a front side junction are the rear metal coverage, the base resistivity and the diffusion profile on the rear. These will be evaluated and discussed in this paper. Front-junction solar cells with low base resistivity have a lower short circuit current when illuminated from the rear due to enhanced recombination in the BSF. Stencil printed rear metallization yields a higher bifaciality factor compared to screen printed by reducing the metal coverage and consumption and maintaining the front side efficiency. For our optimized 239 cm2 bifacial cell we estimate that the output with 20% contributed by the rear side is equivalent to that of a 24.4% efficient monofacial cell.

Investigating dye-sensitised solar cells

NASA Astrophysics Data System (ADS)

Tobin, Laura L.; O'Reilly, Thomas; Zerulla, Dominic; Sheridan, John T.

2010-05-01

At present there is considerable global concern in relation to environmental issues and future energy supplies, for instance climate change (global warming) and the rapid depletion of fossil fuel resources. This trepidation has initiated a more critical investigation into alternative and renewable sources of power such as geothermal, biomass, hydropower, wind and solar energy. The immense dependence on electrical power in today's society has prompted the manufacturing of devices such as photovoltaic (PV) cells to help alleviate and replace current electrical demands of the power grid. The most popular and commercially available PV cells are silicon solar cells which have to date the greatest efficiencies for PV cells. The drawback however is that the manufacturing of these cells is complex and costly due to the expense and difficulty of producing and processing pure silicon. One relatively inexpensive alternative to silicon PV cells that we are currently studying are dye-sensitised solar cells (DSSC or Grätzel Cells). DSSC are biomimetic solar cells which are based on the process of photosynthesis. The SFI Strategic Research Centre for Solar Energy Conversion is a research cluster based in Ireland formed with the express intention of bringing together industry and academia to produce renewable energy solutions. Our specific research area is in DSSC and their electrical properties. We are currently developing testing equipment for arrays of DSSC and developing optoelectronic models which todescribe the performance and behaviour of DSSCs.

Conversion of Fibroblasts to Parvalbumin Neurons by One Transcription Factor, Ascl1, and the Chemical Compound Forskolin*

PubMed Central

Shi, Zixiao; Zhang, Juan; Chen, Shuangquan; Li, Yanxin; Lei, Xuepei; Qiao, Huimin; Zhu, Qianwen; Hu, Baoyang; Zhou, Qi; Jiao, Jianwei

2016-01-01

Abnormalities in parvalbumin (PV)-expressing interneurons cause neurodevelopmental disorders such as epilepsy, autism, and schizophrenia. Unlike other types of neurons that can be efficiently differentiated from pluripotent stem cells, PV neurons were minimally generated using a conventional differentiation strategy. In this study we developed an adenovirus-based transdifferentiation strategy that incorporates an additional chemical compound for the efficient generation of induced PV (iPV) neurons. The chemical compound forskolin combined with Ascl1 induced ∼80% of mouse fibroblasts to iPV neurons. The iPV neurons generated by this procedure matured 5–7 days post infection and were characterized by electrophysiological properties and known neuronal markers, such as PV and GABA. Our studies, therefore, identified an efficient approach for generating PV neurons. PMID:27137935

Induction of Multifunctional Broadly Reactive T Cell Responses by a Plasmodium vivax Circumsporozoite Protein Recombinant Chimera.

PubMed

Cabrera-Mora, Monica; Fonseca, Jairo Andres; Singh, Balwan; Oliveira-Ferreira, Joseli; Lima-Junior, Josué da Costa; Calvo-Calle, J Mauricio; Moreno, Alberto

2015-09-01

Plasmodium vivax is the most widespread species of Plasmodium, causing up to 50% of the malaria cases occurring outside sub-Saharan Africa. An effective vaccine is essential for successful control and potential eradication. A well-characterized vaccine candidate is the circumsporozoite protein (CSP). Preclinical and clinical trials have shown that both antibodies and cellular immune responses have been correlated with protection induced by immunization with CSP. On the basis of our reported approach of developing chimeric Plasmodium yoelii proteins to enhance protective efficacy, we designed PvRMC-CSP, a recombinant chimeric protein based on the P. vivax CSP (PvCSP). In this engineered protein, regions of the PvCSP predicted to contain human T cell epitopes were genetically fused to an immunodominant B cell epitope derived from the N-terminal region I and to repeat sequences representing the two types of PvCSP repeats. The chimeric protein was expressed in soluble form with high yield. As the immune response to PvCSP has been reported to be genetically restricted in the murine model, we tested the immunogenicity of PvRMC-CSP in groups of six inbred strains of mice. PvRMC-CSP was able to induce robust antibody responses in all the mouse strains tested. Synthetic peptides representing the allelic forms of the P. vivax CSP were also recognized to a similar extent regardless of the mouse strain. Furthermore, the immunization regimen induced high frequencies of multifunctional CD4(+) and CD8(+) PvRMC-CSP-specific T cells. The depth and breadth of the immune responses elicited suggest that immunization with PvRMC-CSP can circumvent the genetic restriction of the immune response to P. vivax CSP. Interestingly, PvRMC-CSP was also recognized by naturally acquired antibodies from individuals living in areas where malaria is endemic. These features make PvRMC-CSP a promising vaccine candidate for further development. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Induction of Multifunctional Broadly Reactive T Cell Responses by a Plasmodium vivax Circumsporozoite Protein Recombinant Chimera

PubMed Central

Cabrera-Mora, Monica; Fonseca, Jairo Andres; Singh, Balwan; Oliveira-Ferreira, Joseli; Lima-Junior, Josué da Costa; Calvo-Calle, J. Mauricio

2015-01-01

Plasmodium vivax is the most widespread species of Plasmodium, causing up to 50% of the malaria cases occurring outside sub-Saharan Africa. An effective vaccine is essential for successful control and potential eradication. A well-characterized vaccine candidate is the circumsporozoite protein (CSP). Preclinical and clinical trials have shown that both antibodies and cellular immune responses have been correlated with protection induced by immunization with CSP. On the basis of our reported approach of developing chimeric Plasmodium yoelii proteins to enhance protective efficacy, we designed PvRMC-CSP, a recombinant chimeric protein based on the P. vivax CSP (PvCSP). In this engineered protein, regions of the PvCSP predicted to contain human T cell epitopes were genetically fused to an immunodominant B cell epitope derived from the N-terminal region I and to repeat sequences representing the two types of PvCSP repeats. The chimeric protein was expressed in soluble form with high yield. As the immune response to PvCSP has been reported to be genetically restricted in the murine model, we tested the immunogenicity of PvRMC-CSP in groups of six inbred strains of mice. PvRMC-CSP was able to induce robust antibody responses in all the mouse strains tested. Synthetic peptides representing the allelic forms of the P. vivax CSP were also recognized to a similar extent regardless of the mouse strain. Furthermore, the immunization regimen induced high frequencies of multifunctional CD4+ and CD8+ PvRMC-CSP-specific T cells. The depth and breadth of the immune responses elicited suggest that immunization with PvRMC-CSP can circumvent the genetic restriction of the immune response to P. vivax CSP. Interestingly, PvRMC-CSP was also recognized by naturally acquired antibodies from individuals living in areas where malaria is endemic. These features make PvRMC-CSP a promising vaccine candidate for further development. PMID:26169267

Hybrid photovoltaic-thermoelectric system for concentrated solar energy conversion: Experimental realization and modeling

NASA Astrophysics Data System (ADS)

Beeri, Ofer; Rotem, Oded; Hazan, Eden; Katz, Eugene A.; Braun, Avi; Gelbstein, Yaniv

2015-09-01

An experimental demonstration of the combined photovoltaic (PV) and thermoelectric conversion of concentrated sunlight (with concentration factor, X, up to ˜300) into electricity is presented. The hybrid system is based on a multi-junction PV cell and a thermoelectric generator (TEG). The latter increases the electric power of the system and dissipates some of the excessive heat. For X ≤ 200, the system's maximal efficiency, ˜32%, was mostly due to the contribution from the PV cell. With increasing X and system temperature, the PV cell's efficiency decreased while that of the TEG increased. Accordingly, the direct electrical contribution of the TEG started to dominate in the total system power, reaching ˜20% at X ≈ 290. Using a simple steady state finite element modeling, the cooling effect of the TEG on the hybrid system's efficiency was proved to be even more significant than its direct electrical contribution for high solar concentrations. As a result, the total efficiency contribution of the TEG reached ˜40% at X ≈ 200. This suggests a new system optimization concept that takes into account the PV cell's temperature dependence and the trade-off between the direct electrical generation and cooling capabilities of the TEG. It is shown that the hybrid system has a real potential to exceed 50% total efficiency by using more advanced PV cells and TE materials.

Organic Photovoltaic Solar Cells | Photovoltaic Research | NREL

Science.gov Websites

Organic Photovoltaic Solar Cells Organic Photovoltaic Solar Cells The National Center for Photovoltaics (NCPV) at NREL has strong complementary research capabilities in organic photovoltaic (OPV) cells pages: High-Efficiency Crystalline PV Polycrystalline Thin-Film PV Perovskite and Organic PV Advanced PV

Development of a High Volume Capable Process to Manufacture High Performance Photovoltaic Cells: Cooperative Research and Development Final Report, CRADA Number CRD-08-322

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geisz, J. F.

2012-11-01

The intent of the work is for RFMD and NREL to cooperate in the development of a commercially viable and high volume capable process to manufacture high performance photovoltaic cells, based on inverted metamorphic (IMM) GaAs technology. The successful execution of the agreement will result in the production of a PV cell using technology that is capable of conversion efficiency at par with the market at the time of release (reference 2009: 37-38%), using RFMD's production facilities. The CRADA work has been divided into three phases: (1) a foundation phase where the teams will demonstrate the manufacturing of a basicmore » PV cell at RFMD's production facilities; (2) a technology demonstration phase where the teams will demonstrate the manufacturing of prototype PV cells using IMM technology at RFMD's production facilities, and; (3) a production readiness phase where the teams will demonstrate the capability to manufacture PV cells using IMM technology with high yields, high reliability, high reproducibility and low cost.« less

A Practical Irradiance Model for Bifacial PV Modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marion, Bill; MacAlpine, Sara; Deline, Chris

2017-06-21

A model, suitable for a row or multiple rows of photovoltaic (PV) modules, is presented for estimating the backside irradiance for bifacial PV modules. The model, which includes the effects of shading by the PV rows, is based on the use of configuration factors to determine the fraction of a source of irradiance that is received by the backside of the PV module. Backside irradiances are modeled along the sloped height of the PV module, but assumed not to vary along the length of the PV row. The backside irradiances are corrected for angle-of-incidence losses and may be added tomore » the front side irradiance to determine the total irradiance resource for the PV cell. Model results are compared with the measured backside irradiances for NREL and Sandia PV systems, and with results when using ray tracing software.« less

A Practical Irradiance Model for Bifacial PV Modules: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marion, Bill; MacAlpine, Sara; Deline, Chris

2017-06-15

A model, suitable for a row or multiple rows of photovoltaic (PV) modules, is presented for estimating the backside irradiance for bifacial PV modules. The model, which includes the effects of shading by the PV rows, is based on the use of configuration factors (CFs) to determine the fraction of a source of irradiance that is received by the backside of the PV module. Backside irradiances are modeled along the sloped height of the PV module, but assumed not to vary along the length of the PV row. The backside irradiances are corrected for angle-of-incidence losses and may be addedmore » to the front side irradiance to determine the total irradiance resource for the PV cell. Model results are compared with the measured backside irradiances for NREL and Sandia PV systems, and with results when using the RADIANCE ray tracing program.« less

Research | Photovoltaic Research | NREL

Science.gov Websites

-V cells Hybrid tandems Polycrystalline Thin-Film PV CdTe solar cells CIGS solar cells Perovskites and Organic PV Perovskite solar cells Organic PV solar cells Advanced Materials, Devices, and Science Interfacial and Surface Science Reliability and Engineering Real-Time PV and Solar Resource

Photothermal performance of an amorphous silicon photovoltaic panel integrated in a membrane structure

NASA Astrophysics Data System (ADS)

Zhao, Bing; Hu, Jianhui; Chen, Wujun; Qiu, Zhenyu; Zhou, Jinyu; Qu, Yegao; Ge, Binbin

2016-10-01

The amorphous silicon photovoltaic (a-Si PV) cells are widely used for electricity generation from solar energy. When the a-Si PV cells are integrated into building roofs, such as ETFE (ethylene-tetrafouoroethylene) cushions, the temperature characteristics are indispensible for evaluating the thermal performances of a-Si PV and its constructions. This temperature value is directly dependent on the solar irradiance, wind velocity, ambient temperature and installation form. This paper concerns the field experiments and numerical modeling on the temperature characteristics and temperature value of the a-Si PV integrated in a double-layer ETFE cushion structure. To this end, an experimental model composed of two a-Si PV cells and a double-layer ETFE cushion was developed, and the corresponding experiments were carried out under two typical weather conditions (summer sunny and summer cloudy). The theoretical thermal model was developed based on an energy balance equation taking the short wave radiation, long wave radiation, convection and generated power into account. The measured solar irradiance and air temperature were used as real weather conditions for the thermal model. The corresponding differential equation of the a-Si PV temperature varying with the solar irradiance and air temperature was solved by a newly developed program based on the numerical method. The measured results show that the influence of solar irradiance on the temperature is much more significant than the other parameters, and the maximum temperature variation under sunny conditions is greater than that under cloudy conditions. The comparative study between the experimental and numerical results shows the correct predictions of the a-Si PV temperature under the sunny and cloudy conditions. The maximum difference is 3.9 °C with the acceptable reasons of the solar irradiance fluctuation and the PV thermal response time. These findings will provide useful observations and explanations for evaluating the PV and building performances in relation to temperature.

Development of an Efficient Entire-Capsid-Coding-Region Amplification Method for Direct Detection of Poliovirus from Stool Extracts

PubMed Central

Kilpatrick, David R.; Nakamura, Tomofumi; Burns, Cara C.; Bukbuk, David; Oderinde, Soji B.; Oberste, M. Steven; Kew, Olen M.; Pallansch, Mark A.; Shimizu, Hiroyuki

2014-01-01

Laboratory diagnosis has played a critical role in the Global Polio Eradication Initiative since 1988, by isolating and identifying poliovirus (PV) from stool specimens by using cell culture as a highly sensitive system to detect PV. In the present study, we aimed to develop a molecular method to detect PV directly from stool extracts, with a high efficiency comparable to that of cell culture. We developed a method to efficiently amplify the entire capsid coding region of human enteroviruses (EVs) including PV. cDNAs of the entire capsid coding region (3.9 kb) were obtained from as few as 50 copies of PV genomes. PV was detected from the cDNAs with an improved PV-specific real-time reverse transcription-PCR system and nucleotide sequence analysis of the VP1 coding region. For assay validation, we analyzed 84 stool extracts that were positive for PV in cell culture and detected PV genomes from 100% of the extracts (84/84 samples) with this method in combination with a PV-specific extraction method. PV could be detected in 2/4 stool extract samples that were negative for PV in cell culture. In PV-positive samples, EV species C viruses were also detected with high frequency (27% [23/86 samples]). This method would be useful for direct detection of PV from stool extracts without using cell culture. PMID:25339406

Breakthrough: micro-electronic photovoltaics

ScienceCinema

Okandan, Murat; Gupta, Vipin

2018-01-16

Sandia developed tiny glitter-sized photovoltaic (PV) cells that could revolutionize solar energy collection. The crystalline silicon micro-PV cells will be cheaper and have greater efficiencies than current PV collectors. Micro-PV cells require relatively little material to form well-controlled, highly efficient devices. Cell fabrication uses common microelectric and micro-electromechanical systems (MEMS) techniques.

Silicon nanowires for photovoltaic solar energy conversion.

PubMed

Peng, Kui-Qing; Lee, Shuit-Tong

2011-01-11

Semiconductor nanowires are attracting intense interest as a promising material for solar energy conversion for the new-generation photovoltaic (PV) technology. In particular, silicon nanowires (SiNWs) are under active investigation for PV applications because they offer novel approaches for solar-to-electric energy conversion leading to high-efficiency devices via simple manufacturing. This article reviews the recent developments in the utilization of SiNWs for PV applications, the relationship between SiNW-based PV device structure and performance, and the challenges to obtaining high-performance cost-effective solar cells.

Photovoltaic roofing tile systems

NASA Astrophysics Data System (ADS)

Melchior, B.

The integration of photovoltaic (PV) systems in architecture is discussed. A PV-solar roofing tile system with polymer concrete base; PV-roofing tile with elastomer frame profiles and aluminum profile frames; contact technique; and solar cell modules measuring technique are described. Field tests at several places were conducted on the solar generator, electric current behavior, battery station, electric installation, power conditioner, solar measuring system with magnetic bubble memory technique, data transmission via telephone modems, and data processing system. The very favorable response to the PV-compact system proves the commercial possibilities of photovoltaic integration in architecture.

Oncolytic Rat Parvovirus H-1PV, a Candidate for the Treatment of Human Lymphoma: In Vitro and In Vivo Studies

PubMed Central

Angelova, Assia L; Aprahamian, Marc; Balboni, Ginette; Delecluse, Henri-Jacques; Feederle, Regina; Kiprianova, Irina; Grekova, Svitlana P; Galabov, Angel S; Witzens-Harig, Mathias; Ho, Anthony D; Rommelaere, Jean; Raykov, Zahari

2009-01-01

The incidence of lymphomas developing in both immunocompetent and immunosuppressed patients continues to steadily increase worldwide. Current chemotherapy and immunotherapy approaches have several limitations, such as severe side toxicity and selection of resistant cell variants. Autonomous parvoviruses (PVs), in particular the rat parvovirus H-1PV, have emerged as promising anticancer agents. Although it is apathogenic in humans, H-1PV has been shown to infect and suppress various rat and human tumors in animal models. In this study, we demonstrate the capacity of H-1PV for efficiently killing, through necrosis, cell cultures originating from Burkitt's lymphoma (BL), while sparing normal B lymphocytes. The cytotoxic effect was generally accompanied by a productive H-1PV infection. Remarkably, parvovirus-based monotherapy efficiently suppressed established BL at an advanced stage in a severe combined immunodeficient (SCID) mouse model of the disease. The data show for the first time that an oncolytic parvovirus deserves further consideration as a potential tool for the treatment of some non-Hodgkin B-cell lymphomas, including those resistant to apoptosis induction by rituximab. PMID:19367260

Materials and Devices | Photovoltaic Research | NREL

Science.gov Websites

Polycrystalline Thin-Film PV Cadmium telluride (CdTe) solar cells Copper indium gallium diselenide (CIGS) solar cells Perovskite and Organic PV Perovskite solar cells Perovskite Patent Portfolio Organic PV (OPV ) solar cells Advanced Materials, Devices, and Concepts We explore new PV materials using high-throughput

Enhancement of photovoltaic cell performance using periodic triangular gratings

NASA Astrophysics Data System (ADS)

Bordatchev, Evgueni; Tauhiduzzaman, Mohammed; Dey, Rajat

2014-01-01

The solar energy industry strives to produce more efficient and yet cost effective solar panels each consisting of an array of photovoltaic (PV) cells. The goal of this study was to enhance the performance of PV cells through increasing the cells' optical efficiency defined as a percentage of surface incident light that reaches the PV material. This was achieved through the reduction of waveguide decoupling loss and Fresnel reflection losses by integrating specific nonimaging micro-optical structures on the top surface of existing PV cells. Due to this integration, optical efficiency and performance were increased through the enhancement of light trapping, light guiding, and in-coupling functionalities. Periodic triangular gratings (PTGs) were designed, nonsequentially modeled, optimized, and fabricated in polydimethylsiloxane as proposed micro-optical structures. Then the performance of PV cells with and without integrated PTGs was evaluated and compared. Initial optical simulation results show that an original PV cell (without PTG) exhibits an average optical efficiency of 32.7% over a range of incident light angles between 15 and 90 deg. Integration of the PTG allows the capture of incoming sunlight by total internal reflection (TIR), whence it is reflected back onto the PV cell for multiple consecutive chances for absorption and PV conversion. Geometry of the PTG was optimized with respect to an angle of light incidence of {15, 30, 45, 60, 75, 90} deg. Optical efficiency of the geometrically optimized PTGs was then analyzed under the same set of incident light angles and a maximum optical efficiency of 54.1% was observed for a PV cell with integrated PTG optimized at 90 deg. This is a 53.3% relative improvement in optical performance when compared to an original PV cell. Functional PTG prototypes were then fabricated with optical surface quality (below 10 nm Ra) and integrated with PV cells demonstrating an increase in maximum power by 1.08 mW/cm (7.6% improvement in PV performance) and in short circuit current by 2.39 mA/cm (6.4% improvement).

Muscarinic excitation of parvalbumin-positive interneurons contributes to the severity of pilocarpine-induced seizures

PubMed Central

Yi, Feng; DeCan, Evan; Stoll, Kurt; Marceau, Eric; Deisseroth, Karl; Lawrence, J. Josh

2014-01-01

SUMMARY Objective A common rodent model in epilepsy research employs the muscarinic acetylcholine receptor (mAChR) agonist pilocarpine, yet the mechanisms underlying the induction of pilocarpine-induced seizures (PISs) remain unclear. Global M1 mAChR (M1R) knockout mice are resistant to PISs, implying that M1R activation disrupts excitation/inhibition balance. Parvalbumin-positive (PV) inhibitory neurons express M1 mAChRs, participate in cholinergically-induced oscillations, and can enter a state of depolarization block (DB) during epileptiform activity. Here, we test the hypothesis that pilocarpine activation of M1Rs expressed on PV cells contributes to PISs. Methods CA1 PV cells in PV-CRE mice were visualized with a floxed YFP or hM3Dq-mCherry adeno-associated virus, or by crossing PV-CRE mice with the RosaYFP reporter line. To eliminate M1Rs from PV cells, we generated PV-M1KO mice by crossing PV-CRE and floxed M1 mice. Action potential (AP) frequency was monitored during application of pilocarpine (200 µM). In behavioral experiments, locomotion and seizure symptoms were recorded in WT or PV-M1KO mice during PISs. Results Pilocarpine significantly increased AP frequency in CA1 PV cells into the gamma range. In the continued presence of pilocarpine, a subset (5/7) of PV cells progressed to DB, which was mimicked by hM3Dq activation of Gq-receptor signaling. Pilocarpine-induced depolarization, AP firing at gamma frequency, and progression to DB were prevented in CA1 PV cells of PV-M1KO mice. Finally, compared to WT mice, PV-M1KO mice were associated with reduced severity of PISs. Significance Pilocarpine can directly depolarize PV+ cells via M1R activation but a subset of these cells progress to DB. Our electrophysiological and behavioral results suggest that this mechanism is active during PISs, contributing to a collapse of PV-mediated GABAergic inhibition, dysregulation of excitation/inhibition balance, and increased susceptibility to PISs. PMID:25495999

Conversion of Fibroblasts to Parvalbumin Neurons by One Transcription Factor, Ascl1, and the Chemical Compound Forskolin.

PubMed

Shi, Zixiao; Zhang, Juan; Chen, Shuangquan; Li, Yanxin; Lei, Xuepei; Qiao, Huimin; Zhu, Qianwen; Hu, Baoyang; Zhou, Qi; Jiao, Jianwei

2016-06-24

Abnormalities in parvalbumin (PV)-expressing interneurons cause neurodevelopmental disorders such as epilepsy, autism, and schizophrenia. Unlike other types of neurons that can be efficiently differentiated from pluripotent stem cells, PV neurons were minimally generated using a conventional differentiation strategy. In this study we developed an adenovirus-based transdifferentiation strategy that incorporates an additional chemical compound for the efficient generation of induced PV (iPV) neurons. The chemical compound forskolin combined with Ascl1 induced ∼80% of mouse fibroblasts to iPV neurons. The iPV neurons generated by this procedure matured 5-7 days post infection and were characterized by electrophysiological properties and known neuronal markers, such as PV and GABA. Our studies, therefore, identified an efficient approach for generating PV neurons. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Improved Transparent Conducting Oxides for Photovoltaics: Final Research Report, 1 May 1999--31 December 2002

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mason, T. O.; Chang, R. P. H.; Marks, T. J.

2003-10-01

This subcontract focused on next-generation transparent conducting oxides (TCOs) for improved PV performance. More specifically, there were two research foci: (1) improved Sn-based, n-type TCOs aimed at enhanced CdTe PV cell performance, and (2) novel Cu-based, p-type TCOs applicable to a variety of PV designs. The objective of the research under this subcontract was to identify, explore, evaluate, and develop future generations of photovoltaic technologies that can meet the long-term goal of producing low-cost electricity from sunlight.

Development of an efficient entire-capsid-coding-region amplification method for direct detection of poliovirus from stool extracts.

PubMed

Arita, Minetaro; Kilpatrick, David R; Nakamura, Tomofumi; Burns, Cara C; Bukbuk, David; Oderinde, Soji B; Oberste, M Steven; Kew, Olen M; Pallansch, Mark A; Shimizu, Hiroyuki

2015-01-01

Laboratory diagnosis has played a critical role in the Global Polio Eradication Initiative since 1988, by isolating and identifying poliovirus (PV) from stool specimens by using cell culture as a highly sensitive system to detect PV. In the present study, we aimed to develop a molecular method to detect PV directly from stool extracts, with a high efficiency comparable to that of cell culture. We developed a method to efficiently amplify the entire capsid coding region of human enteroviruses (EVs) including PV. cDNAs of the entire capsid coding region (3.9 kb) were obtained from as few as 50 copies of PV genomes. PV was detected from the cDNAs with an improved PV-specific real-time reverse transcription-PCR system and nucleotide sequence analysis of the VP1 coding region. For assay validation, we analyzed 84 stool extracts that were positive for PV in cell culture and detected PV genomes from 100% of the extracts (84/84 samples) with this method in combination with a PV-specific extraction method. PV could be detected in 2/4 stool extract samples that were negative for PV in cell culture. In PV-positive samples, EV species C viruses were also detected with high frequency (27% [23/86 samples]). This method would be useful for direct detection of PV from stool extracts without using cell culture. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Volume holographic lens spectrum-splitting photovoltaic system for high energy yield with direct and diffuse solar illumination

NASA Astrophysics Data System (ADS)

Chrysler, Benjamin D.; Wu, Yuechen; Yu, Zhengshan; Kostuk, Raymond K.

2017-08-01

In this paper a prototype spectrum-splitting photovoltaic system based on volume holographic lenses (VHL) is designed, fabricated and tested. In spectrum-splitting systems, incident sunlight is divided in spectral bands for optimal conversion by a set of single-junction PV cells that are laterally separated. The VHL spectrumsplitting system in this paper has a form factor similar to conventional silicon PV modules but with higher efficiencies (>30%). Unlike many other spectrum-splitting systems that have been proposed in the past, the system in this work converts both direct and diffuse sunlight while using inexpensive 1-axis tracking systems. The VHL system uses holographic lenses that focus light at a transition wavelength to the boundary between two PV cells. Longer wavelength light is dispersed to the narrow bandgap cell and shorter wavelength light to the wide bandgap cell. A prototype system is designed with silicon and GaAs PV cells. The holographic lenses are fabricated in Covestro Bayfol HX photopolymer by `stitching' together lens segments through sequential masked exposures. The PV cells and holographic lenses were characterized and the data was used in a raytrace simulation and predicts an improvement in total power output of 15.2% compared to a non-spectrum-splitting reference. A laboratory measurement yielded an improvement in power output of 8.5%.

Parvalbumin-expressing ependymal cells in rostral lateral ventricle wall adhesions contribute to aging-related ventricle stenosis in mice.

PubMed

Filice, Federica; Celio, Marco R; Babalian, Alexandre; Blum, Walter; Szabolcsi, Viktoria

2017-10-15

Aging-associated ependymal-cell pathologies can manifest as ventricular gliosis, ventricle enlargement, or ventricle stenosis. Ventricle stenosis and fusion of the lateral ventricle (LV) walls is associated with a massive decline of the proliferative capacities of the stem cell niche in the affected subventricular zone (SVZ) in aging mice. We examined the brains of adult C57BL/6 mice and found that ependymal cells located in the adhesions of the medial and lateral walls of the rostral LVs upregulated parvalbumin (PV) and displayed reactive phenotype, similarly to injury-reactive ependymal cells. However, PV+ ependymal cells in the LV-wall adhesions, unlike injury-reactive ones, did not express glial fibrillary acidic protein. S100B+/PV+ ependymal cells found in younger mice diminished in the LV-wall adhesions throughout aging. We found that periventricular PV-immunofluorescence showed positive correlation to the grade of LV stenosis in nonaged mice (<10-month-old), and that the extent of LV-wall adhesions and LV stenosis was significantly lower in mid-aged (>10-month-old) PV-knock out (PV-KO) mice. This suggests an involvement of PV+ ependymal cells in aging-associated ventricle stenosis. Additionally, we observed a time-shift in microglial activation in the LV-wall adhesions between age-grouped PV-KO and wild-type mice, suggesting a delay in microglial activation when PV is absent from ependymal cells. Our findings implicate that compromised ependymal cells of the adhering ependymal layers upregulate PV and display phenotype shift to "reactive" ependymal cells in aging-related ventricle stenosis; moreover, they also contribute to the progression of LV-wall fusion associated with a decline of the affected SVZ-stem cell niche in aged mice. © 2017 Wiley Periodicals, Inc.

Wind effect on PV module temperature: Analysis of different techniques for an accurate estimation.

NASA Astrophysics Data System (ADS)

Schwingshackl, Clemens; Petitta, Marcello; Ernst Wagner, Jochen; Belluardo, Giorgio; Moser, David; Castelli, Mariapina; Zebisch, Marc; Tetzlaff, Anke

2013-04-01

In this abstract a study on the influence of wind to model the PV module temperature is presented. This study is carried out in the framework of the PV-Alps INTERREG project in which the potential of different photovoltaic technologies is analysed for alpine regions. The PV module temperature depends on different parameters, such as ambient temperature, irradiance, wind speed and PV technology [1]. In most models, a very simple approach is used, where the PV module temperature is calculated from NOCT (nominal operating cell temperature), ambient temperature and irradiance alone [2]. In this study the influence of wind speed on the PV module temperature was investigated. First, different approaches suggested by various authors were tested [1], [2], [3], [4], [5]. For our analysis, temperature, irradiance and wind data from a PV test facility at the airport Bolzano (South Tyrol, Italy) from the EURAC Institute of Renewable Energies were used. The PV module temperature was calculated with different models and compared to the measured PV module temperature at the single panels. The best results were achieved with the approach suggested by Skoplaki et al. [1]. Preliminary results indicate that for all PV technologies which were tested (monocrystalline, amorphous, microcrystalline and polycrystalline silicon and cadmium telluride), modelled and measured PV module temperatures show a higher agreement (RMSE about 3-4 K) compared to standard approaches in which wind is not considered. For further investigation the in-situ measured wind velocities were replaced with wind data from numerical weather forecast models (ECMWF, reanalysis fields). Our results show that the PV module temperature calculated with wind data from ECMWF is still in very good agreement with the measured one (R² > 0.9 for all technologies). Compared to the previous analysis, we find comparable mean values and an increasing standard deviation. These results open a promising approach for PV module temperature estimation using meteorological parameters. References: [1] Skoplaki, E. et al., 2008: A simple correlation for the operating temperature of photovoltaic modules of arbitrary mounting, Solar Energy Materials & Solar Cells 92, 1393-1402 [2] Skoplaki, E. et al., 2008: Operating temperature of photovoltaic modules: A survey of pertinent correlations, Renewable Energy 34, 23-29 [3] Koehl, M. et al., 2011: Modeling of the nominal operating cell temperature based on outdoor weathering, Solar Energy Materials & Solar Cells 95, 1638-1646 [4] Mattei, M. et al., 2005: Calculation of the polycrystalline PV module temperature using a simple method of energy balance, Renewable Energy 31, 553-567 [5] Kurtz, S. et al.: Evaluation of high-temperature exposure of rack-mounted photovoltaic modules

Preclinical Testing of an Oncolytic Parvovirus: Standard Protoparvovirus H-1PV Efficiently Induces Osteosarcoma Cell Lysis In Vitro

PubMed Central

Leuchs, Barbara; Frank-Stöhr, Monika; Schlehofer, Jörg R.; Rommelaere, Jean; Lacroix, Jeannine

2017-01-01

Osteosarcoma is the most frequent malignant disease of the bone. On the basis of early clinical experience in the 1960s with H-1 protoparvovirus (H-1PV) in osteosarcoma patients, this effective oncolytic virus was selected for systematic preclinical testing on various osteosarcoma cell cultures. A panel of five human osteosarcoma cell lines (CAL 72, H-OS, MG-63, SaOS-2, U-2OS) was tested. Virus oncoselectivity was confirmed by infecting non-malignant human neonatal fibroblasts and osteoblasts used as culture models of non-transformed mesenchymal cells. H-1PV was found to enter osteosarcoma cells and to induce viral DNA replication, transcription of viral genes, and translation to viral proteins. After H-1PV infection, release of infectious viral particles from osteosarcoma cells into the supernatant indicated successful viral assembly and egress. Crystal violet staining revealed progressive cytomorphological changes in all osteosarcoma cell lines. Infection of osteosarcoma cell lines with the standard H-1PV caused an arrest of the cell cycle in the G2 phase, and these lines had a limited capacity for standard H-1PV virus replication. The cytotoxicity of wild-type H-1PV virus towards osteosarcoma cells was compared in vitro with that of two variants, Del H-1PV and DM H-1PV, previously described as fitness variants displaying higher infectivity and spreading in human transformed cell lines of different origins. Surprisingly, wild-type H-1PV displayed the strongest cytostatic and cytotoxic effects in this analysis and thus seems the most promising for the next preclinical validation steps in vivo. PMID:29039746

Preclinical Testing of an Oncolytic Parvovirus: Standard Protoparvovirus H-1PV Efficiently Induces Osteosarcoma Cell Lysis In Vitro.

PubMed

Geiss, Carsten; Kis, Zoltán; Leuchs, Barbara; Frank-Stöhr, Monika; Schlehofer, Jörg R; Rommelaere, Jean; Dinsart, Christiane; Lacroix, Jeannine

2017-10-17

Osteosarcoma is the most frequent malignant disease of the bone. On the basis of early clinical experience in the 1960s with H-1 protoparvovirus (H-1PV) in osteosarcoma patients, this effective oncolytic virus was selected for systematic preclinical testing on various osteosarcoma cell cultures. A panel of five human osteosarcoma cell lines (CAL 72, H-OS, MG-63, SaOS-2, U-2OS) was tested. Virus oncoselectivity was confirmed by infecting non-malignant human neonatal fibroblasts and osteoblasts used as culture models of non-transformed mesenchymal cells. H-1PV was found to enter osteosarcoma cells and to induce viral DNA replication, transcription of viral genes, and translation to viral proteins. After H-1PV infection, release of infectious viral particles from osteosarcoma cells into the supernatant indicated successful viral assembly and egress. Crystal violet staining revealed progressive cytomorphological changes in all osteosarcoma cell lines. Infection of osteosarcoma cell lines with the standard H-1PV caused an arrest of the cell cycle in the G2 phase, and these lines had a limited capacity for standard H-1PV virus replication. The cytotoxicity of wild-type H-1PV virus towards osteosarcoma cells was compared in vitro with that of two variants, Del H-1PV and DM H-1PV, previously described as fitness variants displaying higher infectivity and spreading in human transformed cell lines of different origins. Surprisingly, wild-type H-1PV displayed the strongest cytostatic and cytotoxic effects in this analysis and thus seems the most promising for the next preclinical validation steps in vivo.

Power Management System Design for Solar-Powered UAS

DTIC Science & Technology

2015-12-01

PV cells would have their own MPPT modules, which would enable two major advantages. The first can be considered more important to land-based solar ...The efficiency of the PV array is represented by ηpv. R represents the solar irradiance, and θ represents the angle between the array and the sun...SYSTEM DESIGN FOR SOLAR -POWERED UAS by Robert T. Fauci III December 2015 Thesis Advisor: Alejandro Hernandez Co-Advisor: Kevin Jones

The Status and Outlook for the Photovoltaics Industry

NASA Astrophysics Data System (ADS)

Carlson, David

2006-03-01

The first silicon solar cell was made at Bell Labs in 1954, and over the following decades, shipments of photovoltaic (PV) modules increased at a rate of about 18% annually. In the last several years, the annual growth rate has increased to ˜ 35% due largely to government-supported programs in Japan and Germany. Silicon technology has dominated the PV industry since its inception, and in 2005 about 65% of all solar cells were made from polycrystalline (or multicrystalline) silicon, 24% from monocrystalline silicon and ˜ 4% from ribbon silicon. While conversion efficiencies as high as 24.7% have been obtained in the laboratory for silicon solar cells, the best efficiencies for commercial PV modules are in the range of 17 18% (the efficiency limit for a silicon solar cell is ˜ 29%). A number of companies are commercializing solar cells based on other materials such as amorphous silicon, microcrystalline silicon, cadmium telluride, copper-indium-gallium-diselenide (CIGS), gallium arsenide (and related compounds) and dye- sensitized titanium oxide. Thin film CIGS solar cells have been fabricated with conversion efficiencies as high as 19.5% while efficiencies as high as 39% have been demonstrated for a GaInP/Ga(In)As/Ge triple-junction cell operating at a concentration of 236 suns. Thin film solar cells are being used in consumer products and in some building-integrated applications, while PV concentrator systems are being tested in grid-connected arrays located in high solar insolation areas. Nonetheless, crystalline silicon PV technology is likely to dominate the terrestrial market for at least the next decade with module efficiencies > 20% and module prices of < 1/Wp expected by 2020, which in turn should allow significant penetration of the utility grid market. However, crystalline silicon solar cells may be challenged in the next decade or two by new low-cost, high performance devices based on organic materials and nanotechnology.

Research Update: Emerging chalcostibite absorbers for thin-film solar cells

DOE PAGES

de Souza Lucas, Francisco Willian; Zakutayev, Andriy

2018-06-04

Copper antimony chalcogenides CuSbCh 2 (Ch=S, Se) are an emerging family of absorbers studied for thin-film solar cells. These non-toxic and Earth-abundant materials show a layered low-dimensional chalcostibite crystal structure, leading to interesting optoelectronic properties for applications in photovoltaic (PV) devices. This research update describes the CuSbCh 2 crystallographic structures, synthesis methods, competing phases, band structures, optoelectronic properties, point defects, carrier dynamics, and interface band offsets, based on experimental and theoretical data. Correlations between these absorber properties and PV device performance are discussed, and opportunities for further increase in the efficiency of the chalcostibite PV devices are highlighted.

Research Update: Emerging chalcostibite absorbers for thin-film solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

de Souza Lucas, Francisco Willian; Zakutayev, Andriy

Copper antimony chalcogenides CuSbCh 2 (Ch=S, Se) are an emerging family of absorbers studied for thin-film solar cells. These non-toxic and Earth-abundant materials show a layered low-dimensional chalcostibite crystal structure, leading to interesting optoelectronic properties for applications in photovoltaic (PV) devices. This research update describes the CuSbCh 2 crystallographic structures, synthesis methods, competing phases, band structures, optoelectronic properties, point defects, carrier dynamics, and interface band offsets, based on experimental and theoretical data. Correlations between these absorber properties and PV device performance are discussed, and opportunities for further increase in the efficiency of the chalcostibite PV devices are highlighted.

Diamond encapsulated photovoltaics for transdermal power delivery.

PubMed

Ahnood, A; Fox, K E; Apollo, N V; Lohrmann, A; Garrett, D J; Nayagam, D A X; Karle, T; Stacey, A; Abberton, K M; Morrison, W A; Blakers, A; Prawer, S

2016-03-15

A safe, compact and robust means of wireless energy transfer across the skin barrier is a key requirement for implantable electronic devices. One possible approach is photovoltaic (PV) energy delivery using optical illumination at near infrared (NIR) wavelengths, to which the skin is highly transparent. In the work presented here, a subcutaneously implantable silicon PV cell, operated in conjunction with an external NIR laser diode, is developed as a power delivery system. The biocompatibility and long-term biostability of the implantable PV is ensured through the use of an hermetic container, comprising a transparent diamond capsule and platinum wire feedthroughs. A wavelength of 980 nm is identified as the optimum operating point based on the PV cell's external quantum efficiency, the skin's transmission spectrum, and the wavelength dependent safe exposure limit of the skin. In bench-top experiments using an external illumination intensity of 0.7 W/cm(2), a peak output power of 2.7 mW is delivered to the implant with an active PV cell dimension of 1.5 × 1.5 × 0.06 mm(3). This corresponds to a volumetric power output density of ~20 mW/mm(3), significantly higher than power densities achievable using inductively coupled coil-based approaches used in other medical implant systems. This approach paves the way for further ministration of bionic implants. Copyright © 2015 Elsevier B.V. All rights reserved.

Novel Mechanisms of Target Cell Death and Survival and of Therapeutic Action of IVIg in Pemphigus

PubMed Central

Arredondo, Juan; Chernyavsky, Alexander I.; Karaouni, Ali; Grando, Sergei A.

2005-01-01

Pemphigus vulgaris (PV) is a potentially lethal mucocutaneous blistering disease characterized by cell-cell detachment within the stratified epithelium (acantholysis) caused by IgG autoantibodies. Intravenous immunoglobulin (IVIg) therapy effectively treats PV, but the mechanism is not fully understood. To further understand acantholysis and the efficacy of IVIg, we measured effects of IgG fractions from PV patients on keratinocyte death processes. Using IgGs from representative PV patients who improved with IVIg, we identified apoptotic and oncotic signaling pathways in in vitro and in vivo PV models. We identified two groups of PV patients, each producing autoantibodies activating predominantly either apoptotic or oncotic cell death pathway. Experimental treatments with caspase 3 or calpain inhibitors demonstrated that PV IgGs induced acantholysis through both pathways. Upstream, the apoptotic signaling involved activation of caspases 8 and 3 and up-regulation of Fas ligand mRNA, whereas calpain-mediated cell death depended on elevated intracellular free Ca2+. IVIg reduced PV IgG-mediated acantholysis and cell death and up-regulated the caspase inhibitor FLIP and the calpain inhibitor calpastatin. These results indicate that in different PV patients, IgG-induced acantholysis proceeds predominantly via distinct, yet complementary, pathways of programmed cell death differentially mediated by apoptosis and oncosis effectors, with IVIg protecting target cells by up-regulating endogenous caspase and calpain inhibitors. PMID:16314468

A Novel Technique for Maximum Power Point Tracking of a Photovoltaic Based on Sensing of Array Current Using Adaptive Neuro-Fuzzy Inference System (ANFIS)

NASA Astrophysics Data System (ADS)

El-Zoghby, Helmy M.; Bendary, Ahmed F.

2016-10-01

Maximum Power Point Tracking (MPPT) is now widely used method in increasing the photovoltaic (PV) efficiency. The conventional MPPT methods have many problems concerning the accuracy, flexibility and efficiency. The MPP depends on the PV temperature and solar irradiation that randomly varied. In this paper an artificial intelligence based controller is presented through implementing of an Adaptive Neuro-Fuzzy Inference System (ANFIS) to obtain maximum power from PV. The ANFIS inputs are the temperature and cell current, and the output is optimal voltage at maximum power. During operation the trained ANFIS senses the PV current using suitable sensor and also senses the temperature to determine the optimal operating voltage that corresponds to the current at MPP. This voltage is used to control the boost converter duty cycle. The MATLAB simulation results shows the effectiveness of the ANFIS with sensing the PV current in obtaining the MPPT from the PV.

Progress of the PV Technology Incubator Project Towards an Enhanced U.S. Manufacturing Base

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ullal, H.; Mitchell, R.; Keyes, B.

In this paper, we report on the major accomplishments of the U.S. Department of Energy's (DOE) Solar Energy Technologies Program (SETP) Photovoltaic (PV) Technology Incubator project. The Incubator project facilitates a company's transition from developing a solar cell or PV module prototype to pilot- and large-scale U.S. manufacturing. The project targets small businesses that have demonstrated proof-of-concept devices or processes in the laboratory. Their success supports U.S. Secretary of Energy Steven Chu's SunShot Initiative, which seeks to achieve PV technologies that are cost-competitive without subsidies at large scale with fossil-based energy sources by the end of this decade. The Incubatormore » Project has enhanced U.S. PV manufacturing capacity and created more than 1200 clean energy jobs, resulting in an increase in American economic competitiveness. The investment raised to date by these PV Incubator companies as a result of DOE's $ 59 million investment total nearly $ 1.3 billion.« less

Why silicon is and will remain the dominant photovoltaic material

NASA Astrophysics Data System (ADS)

Singh, Rajendra

2009-07-01

Rising demands of energy in emerging economies, coupled with the green house gas emissions related problems around the globe have provided a unique opportunity of exploiting the advantages offered by photovoltaic (PV) systems for green energy electricity generation. Similar to cell phones, power generated by PV systems can reach over two billion people worldwide who have no access to clean energy. Only silicon based PV devices meet the low-cost manufacturing criterion of clean energy conversion (abundance of raw material and no environmental health and safety issues). The use of larger size glass substrates and manufacturing techniques similar to the ones used by the liquid crystal display industry and the large scale manufacturing of amorphous silicon thin films based modules (~ GW per year manufacturing at a single location) can lead to installed PV system cost of $3/Wp. This will open a huge market for grid connected PV systems and related markets. With further research and development, this approach can provide $2/Wp installed PV system costs in the next few years. At this cost level, PV electricity generation is competitive with any other technology, and PV power generation can be a dominant electricity generation technology in the 21st century.

Thin-film filament-based solar cells and modules

NASA Astrophysics Data System (ADS)

Tuttle, J. R.; Cole, E. D.; Berens, T. A.; Alleman, J.; Keane, J.

1997-04-01

This concept paper describes a patented, novel photovoltaic (PV) technology that is capable of achieving near-term commercialization and profitability based upon design features that maximize product performance while minimizing initial and future manufacturing costs. DayStar Technologies plans to exploit these features and introduce a product to the market based upon these differential positions. The technology combines the demonstrated performance and reliability of existing thin-film PV product with a cell and module geometry that cuts material usage by a factor of 5, and enhances performance and manufacturability relative to standard flat-plate designs. The target product introduction price is 1.50/Watt-peak (Wp). This is approximately one-half the cost of the presently available PV product. Additional features include: increased efficiency through low-level concentration, no scribe or grid loss, simple series interconnect, high voltage, light weight, high-throughput manufacturing, large area immediate demonstration, flexibility, modularity.

Halide Perovskites: New Science or ``only'' future Energy Converters?

NASA Astrophysics Data System (ADS)

Cahen, David

Over the years many new ideas and systems for photovoltaic, PV, solar to electrical energy conversion have been explored, but only a few have really impacted PV's role as a more sustainable, environmentally less problematic and safer source of electrical power than fossil or nuclear fuel-based generation. Will Halide Perovskites, HaPs, be able to join the very select group of commercial PV options? To try to address this question, we put Halide Perovskite(HaP) cells in perspective with respect to other PV cells. Doing so also allows to identify fundamental scientific issues that can be important for PV and beyond. What remains to be seen is if those issues lead to new science or scientific insights or additional use of existing models. Being more specific is problematic, given the fact that this will be 4 months after writing this abstract. Israel National Nano-initiative, Weizmann Institute of Science's Alternative sustainable Energy Research Initiative; Israel Ministries of -Science and of -Infrastructure, Energy & Water.

Low Illumination Light (LIL) Solar Cells: Indoor and Monochromatic Light Harvesting

DTIC Science & Technology

2015-11-01

photovoltaic ( PV ) solar cells under low intensity and narrow light spectrum conditions has not been clearly examined. PV operating values under 1 sun...3. PV Fundamental Losses under Low-Light Conditions 5 4. Experiment Setup 9 4.1 Materials 9 4.1.1 Light Sources and Spectra 9 4.1.2 PV Solar ...http://www.mjinc.com/newsArticle2012_Mar15.html ..........................4 Fig. 4 Three energy and power densities ranges for PV solar cells

CuInSe2-Based Thin-Film Photovoltaic Technology in the Gigawatt Production Era

NASA Astrophysics Data System (ADS)

Kushiya, Katsumi

2012-10-01

The objective of this paper is to review current status and future prospect on CuInSe2 (CIS)-based thin-film photovoltaic (PV) technology. In CIS-based thin-film PV technology, total-area cell efficiency in a small-area (i.e., smaller than 1 cm2) solar cell with top grids has been over 20%, while aperture-area efficiency in a large-area (i.e., larger than 800 cm2 as definition) monolithic module is approaching to an 18% milestone. However, most of the companies with CIS-based thin-film PV technology still stay at a production research stage, except Solar Frontier K.K. In July, 2011, Solar Frontier has joined the gigawatt (GW) group by starting up their third facility with a 0.9-GW/year production capacity. They are keeping the closest position to pass a 16% module-efficiency border by transferring the developed technologies in the R&D and accelerating the preparation for the future based on the concept of a product life-cycle management.

Chapter 10.2: Encapsulant Materials for PV Modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kempe, Michael D

2017-01-07

Encapsulant materials used in photovoltaic (PV) modules serve multiple purposes; it provides optical coupling of PV cells and protection against environmental stress. Polymers must perform these functions under prolonged periods of high temperature, humidity, and UV radiation. When PV panels were first developed in the 1960s and the 1970s, the dominant encapsulants were based on polydimethyl siloxane (PDMS). Ethylene-co-vinyl acetate (EVA) is currently the dominant encapsulant chosen for PV applications, not because it has the best combination of properties, but because it is an economical option with an established history of acceptable durability. Getting new products onto the market ismore » challenging because there is no room for dramatic improvements, and one must balance the initial cost and performance with the unknowns of long-term service life. Recently, there has been renewed interest in using alternative encapsulant materials with some significant manufacturers switching from EVA to polyolefin elastomer-based (POE) alternatives.« less

Capacity of wild-type and chemokine-armed parvovirus H-1PV for inhibiting neo-angiogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lavie, Muriel; Struyf, Sofie; Stroh-Dege, Alexandra

2013-12-15

Anti-angiogenic therapy has been recognized as a powerful potential strategy for impeding the growth of various tumors. However no major therapeutic effects have been observed to date, mainly because of the emergence of several resistance mechanisms. Among novel strategies to target tumor vasculature, some oncolytic viruses open up new prospects. In this context, we addressed the question whether the rodent parvovirus H-1PV can target endothelial cells. We show that cultures of human normal (HUVEC) and immortalized (KS-IMM) endothelial cells sustain an abortive viral cycle upon infection with H-1PV and are sensitive to H-1PV cytotoxicity. H-1PV significantly inhibits infected KS-IMM tumormore » growth. This effect may be traced back by the virus ability to both kill proliferating endothelial cells and inhibit VEGF production Recombinant H-1PV vectors can also transduce tumor cells with chemokines endowed with anti-angiogenesis properties, and warrant further validation for the treatment of highly vascularized tumors. - Highlights: • The oncolytic parvovirus H-1PV can target endothelial cells. • Abortive viral cycle upon infection of endothelial cells with H-1PV. • Inhibition of VEGF expression and KS-IMM tumor growth by H-1PV.« less

Fya/Fyb antigen polymorphism in human erythrocyte Duffy antigen affects susceptibility to Plasmodium vivax malaria

PubMed Central

King, Christopher L.; Adams, John H.; Xianli, Jia; Grimberg, Brian T.; McHenry, Amy M.; Greenberg, Lior J.; Siddiqui, Asim; Howes, Rosalind E.; da Silva-Nunes, Monica; Ferreira, Marcelo U.; Zimmerman, Peter A.

2011-01-01

Plasmodium vivax (Pv) is a major cause of human malaria and is increasing in public health importance compared with falciparum malaria. Pv is unique among human malarias in that invasion of erythrocytes is almost solely dependent on the red cell's surface receptor, known as the Duffy blood-group antigen (Fy). Fy is an important minor blood-group antigen that has two immunologically distinct alleles, referred to as Fya or Fyb, resulting from a single-point mutation. This mutation occurs within the binding domain of the parasite's red cell invasion ligand. Whether this polymorphism affects susceptibility to clinical vivax malaria is unknown. Here we show that Fya, compared with Fyb, significantly diminishes binding of Pv Duffy binding protein (PvDBP) at the erythrocyte surface, and is associated with a reduced risk of clinical Pv in humans. Erythrocytes expressing Fya had 41–50% lower binding compared with Fyb cells and showed an increased ability of naturally occurring or artificially induced antibodies to block binding of PvDBP to their surface. Individuals with the Fya+b− phenotype demonstrated a 30–80% reduced risk of clinical vivax, but not falciparum malaria in a prospective cohort study in the Brazilian Amazon. The Fya+b− phenotype, predominant in Southeast Asian and many American populations, would confer a selective advantage against vivax malaria. Our results also suggest that efficacy of a PvDBP-based vaccine may differ among populations with different Fy phenotypes. PMID:22123959

Fy(a)/Fy(b) antigen polymorphism in human erythrocyte Duffy antigen affects susceptibility to Plasmodium vivax malaria.

PubMed

King, Christopher L; Adams, John H; Xianli, Jia; Grimberg, Brian T; McHenry, Amy M; Greenberg, Lior J; Siddiqui, Asim; Howes, Rosalind E; da Silva-Nunes, Monica; Ferreira, Marcelo U; Zimmerman, Peter A

2011-12-13

Plasmodium vivax (Pv) is a major cause of human malaria and is increasing in public health importance compared with falciparum malaria. Pv is unique among human malarias in that invasion of erythrocytes is almost solely dependent on the red cell's surface receptor, known as the Duffy blood-group antigen (Fy). Fy is an important minor blood-group antigen that has two immunologically distinct alleles, referred to as Fy(a) or Fy(b), resulting from a single-point mutation. This mutation occurs within the binding domain of the parasite's red cell invasion ligand. Whether this polymorphism affects susceptibility to clinical vivax malaria is unknown. Here we show that Fy(a), compared with Fy(b), significantly diminishes binding of Pv Duffy binding protein (PvDBP) at the erythrocyte surface, and is associated with a reduced risk of clinical Pv in humans. Erythrocytes expressing Fy(a) had 41-50% lower binding compared with Fy(b) cells and showed an increased ability of naturally occurring or artificially induced antibodies to block binding of PvDBP to their surface. Individuals with the Fy(a+b-) phenotype demonstrated a 30-80% reduced risk of clinical vivax, but not falciparum malaria in a prospective cohort study in the Brazilian Amazon. The Fy(a+b-) phenotype, predominant in Southeast Asian and many American populations, would confer a selective advantage against vivax malaria. Our results also suggest that efficacy of a PvDBP-based vaccine may differ among populations with different Fy phenotypes.

Application of carbon nanotubes in perovskite solar cells: A review

NASA Astrophysics Data System (ADS)

Oo, Thet Tin; Debnath, Sujan

2017-11-01

Solar power, as alternative renewable energy source, has gained momentum in global energy generation in recent time. Solar photovoltaics (PV) systems now fulfill a significant portion of electricity demand and the capacity of solar PV capacity is growing every year. PV cells efficiency has improved significantly following decades of research, evolving into third generations of PV cells. These third generation PV cells are set out to provide low-cost and efficient PV systems, further improving the commercial competitiveness of solar energy generation. Among these latest generations of PV cells, perovskite solar cells have gained attraction due to the simple manufacturing process and the immense growth in PV efficiency in a short period of research and development. Despite these advantages, perovskite solar cells are known for the weak stability and decomposition in exposure to humidity and high temperature, hindering the possibility of commercialization. This paper will discuss the role of carbon nanotubes (CNTs) in improving the efficiency and stability of perovskite solar cells, in various components such as perovskite layer and hole transport layer, as well as the application of CNTs in unique aspects. These includes the use of CNTs fiber in making the perovskite solar cells flexible, as well as simplification of perovskite PV production by using CNT flash evaporation printing process. Despite these advances, challenges remain in incorporation CNTs into perovskite such as lower conversion efficiency compared to rare earth metals and improvements need to be made. Thus, the paper will be also highlighting the CNTs materials suggested for further research and improvement of perovskite solar cells.

Interband Cascade Photovoltaic Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Rui Q.; Santos, Michael B.; Johnson, Matthew B.

2014-09-24

In this project, we are performing basic and applied research to systematically investigate our newly proposed interband cascade (IC) photovoltaic (PV) cells [1]. These cells follow from the great success of infrared IC lasers [2-3] that pioneered the use of quantum-engineered IC structures. This quantum-engineered approach will enable PV cells to efficiently convert infrared radiation from the sun or other heat source, to electricity. Such cells will have important applications for more efficient use of solar energy, waste-heat recovery, and power beaming in combination with mid-infrared lasers. The objectives of our investigations are to: achieve extensive understanding of the fundamentalmore » aspects of the proposed PV structures, develop the necessary knowledge for making such IC PV cells, and demonstrate prototype working PV cells. This research will focus on IC PV structures and their segments for utilizing infrared radiation with wavelengths from 2 to 5 μm, a range well suited for emission by heat sources (1,000-2,000 K) that are widely available from combustion systems. The long-term goal of this project is to push PV technology to longer wavelengths, allowing for relatively low-temperature thermal sources. Our investigations address material quality, electrical and optical properties, and their interplay for the different regions of an IC PV structure. The tasks involve: design, modeling and optimization of IC PV structures, molecular beam epitaxial growth of PV structures and relevant segments, material characterization, prototype device fabrication and testing. At the end of this program, we expect to generate new cutting-edge knowledge in the design and understanding of quantum-engineered semiconductor structures, and demonstrate the concepts for IC PV devices with high conversion efficiencies.« less

Transferrin Receptor 1 Facilitates Poliovirus Permeation of Mouse Brain Capillary Endothelial Cells.

PubMed

Mizutani, Taketoshi; Ishizaka, Aya; Nihei, Coh-Ichi

2016-02-05

As a possible route for invasion of the CNS, circulating poliovirus (PV) in the blood is believed to traverse the blood-brain barrier (BBB), resulting in paralytic poliomyelitis. However, the underlying mechanism is poorly understood. In this study, we demonstrated that mouse transferrin receptor 1 (mTfR1) is responsible for PV attachment to the cell surface, allowing invasion into the CNS via the BBB. PV interacts with the apical domain of mTfR1 on mouse brain capillary endothelial cells (MBEC4) in a dose-dependent manner via its capsid protein (VP1). We found that F-G, G-H, and H-I loops in VP1 are important for this binding. However, C-D, D-E, and E-F loops in VP1-fused Venus proteins efficiently penetrate MBEC4 cells. These results imply that the VP1 functional domain responsible for cell attachment is different from that involved in viral permeation of the brain capillary endothelium. We observed that co-treatment of MBEC4 cells with excess PV particles but not dextran resulted in blockage of transferrin transport into cells. Using the Transwell in vitro BBB model, transferrin co-treatment inhibited permeation of PV into MBEC4 cells and delayed further viral permeation via mTfR1 knockdown. With mTfR1 as a positive mediator of PV-host cell attachment and PV permeation of MBEC4 cells, our results indicate a novel role of TfR1 as a cellular receptor for human PV receptor/CD155-independent PV invasion of the CNS. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Toxoplasma gondii sequesters lysosomes from mammalian hosts in the vacuolar space.

PubMed

Coppens, Isabelle; Dunn, Joe Dan; Romano, Julia D; Pypaert, Marc; Zhang, Hui; Boothroyd, John C; Joiner, Keith A

2006-04-21

The intracellular compartment harboring Toxoplasma gondii satisfies the parasite's nutritional needs for rapid growth in mammalian cells. We demonstrate that the parasitophorous vacuole (PV) of T. gondii accumulates material coming from the host mammalian cell via the exploitation of the host endo-lysosomal system. The parasite actively recruits host microtubules, resulting in selective attraction of endo-lysosomes to the PV. Microtubule-based invaginations of the PV membrane serve as conduits for the delivery of host endo-lysosomes within the PV. These tubular conduits are decorated by a parasite coat, including the tubulogenic protein GRA7, which acts like a garrote that sequesters host endocytic organelles in the vacuolar space. These data define an unanticipated process allowing the parasite intimate and concentrated access to a diverse range of low molecular weight components produced by the endo-lysosomal system. More generally, they identify a unique mechanism for unidirectional transport and sequestration of host organelles.

Analyzing luminescent solar concentrators with front-facing photovoltaic cells using weighted Monte Carlo ray tracing

NASA Astrophysics Data System (ADS)

Woei Leow, Shin; Corrado, Carley; Osborn, Melissa; Isaacson, Michael; Alers, Glenn; Carter, Sue A.

2013-06-01

Luminescent solar concentrators (LSC) collect ambient light from a broad range of angles and concentrate the captured light onto photovoltaic (PV) cells. LSCs with front-facing cells collect direct and indirect sunlight ensuring a gain factor greater than one. The flexible placement and percentage coverage of PV cells on the LSC panel allow for layout adjustments to be made in order to balance re-absorption losses and the level of light concentration desired. A weighted Monte Carlo ray tracing program was developed to study the transport of photons and loss mechanisms in the LSC to aid in design optimization. The program imports measured absorption/emission spectra of an organic luminescent dye (LR305), the transmission coefficient, and refractive index of acrylic as parameters that describe the system. Simulations suggest that for LR305, 8-10 cm of luminescent material surrounding the PV cell yields the highest increase in power gain per unit area of LSC added, thereby determining the ideal spacing between PV cells in the panel. For rectangular PV cells, results indicate that for each centimeter of PV cell width, an additional increase of 0.15 mm to the waveguide thickness is required to efficiently transport photon collected by the LSC to the PV cell with minimal loss.

Comparative analysis of microbial fuel cell based biosensors developed with a mixed culture and Shewanella loihica PV-4 and underlying biological mechanism.

PubMed

Yi, Yue; Xie, Beizhen; Zhao, Ting; Liu, Hong

2018-06-13

Microbial fuel cell based biosensors (MFC-biosensors) utilize anode biofilms as biological recognition elements to monitor biochemical oxygen demand (BOD) and biotoxicity. However, the relatively poor sensitivity constrains the application of MFC-biosensors. To address this limitation, this study provided a systematic comparison of sensitivity between the MFC-biosensors constructed with two inocula. Higher biomass density and viability were both observed in the anode biofilm of the mixed culture MFC, which resulted in better sensitivity for BOD assessment. Compared with using mixed culture as inoculum, the anode biofilm developed with Shewanella loihica PV-4 presented lower content of extracellular polymeric substances and poorer ability to secrete protein under toxic shocks. Moreover, the looser structure in the S. loihica PV-4 biofilm further facilitated its susceptibilities to toxic agents. Therefore, the MFC-biosensor with a pure culture of S. loihica PV-4 delivered higher sensitivity for biotoxicity monitoring. This study proposed a new perspective to enhance sensor performance. Copyright © 2018 Elsevier Ltd. All rights reserved.

Possible role of natural killer cells in pemphigus vulgaris − preliminary observations

PubMed Central

Stern, J N H; Keskin, D B; Barteneva, N; Zuniga, J; Yunis, E J; Ahmed, A R

2008-01-01

Pemphigus vulgaris (PV) is an autoimmune blistering disease that affects the skin and multiple mucous membranes, and is caused by antibodies to desmoglein (Dsg) 1 and 3. Natural killer (NK) cells have a role in autoimmunity, but their role in PV is not known. NK cells in the peripheral blood leucocytes (PBL) of 15 untreated Caucasian patients with active PV were studied and compared with healthy controls for the expression of major histocompatibility complex (MHC) class II and co-stimulatory molecules. CD56+ CD16- CD3- NK or CD56+ CD16+ CD3- NK cells from the PBL of PV patients co-express MHC class II and co-stimulatory molecule B7-H3 without exogenous stimulation. CD4+ T cells from the PBL and perilesional skin of PV patients were co-cultured with CD56+ CD3- NK cells from the PBL of the same patients; in the presence of Dsg3 peptides underwent statistically significant proliferation, indicating that NK cells functioned as antigen-presenting cells. Supernatants from these co-cultures and serum of the same patients with active PV had statistically significantly elevated levels of interleukin (IL)-6, IL-8 and interferon-γ, compared with controls indicating that the NK cells stimulated CD4+ T cells to produce proinflammatory cytokines. In these experiments, we present preliminary evidence that NK cells may play a role in the pathobiology of PV. PMID:18373702

Impact of residential PV adoption on Retail Electricity Rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, DWH; Adlakha, S; Low, SH

2013-11-01

The price of electricity supplied from home rooftop photo voltaic (PV) solar cells has fallen below the retail price of grid electricity in some areas. A number of residential households have an economic incentive to install rooftop PV systems and reduce their purchases of electricity from the grid. A significant portion of the costs incurred by utility companies are fixed costs which must be recovered even as consumption falls. Electricity rates must increase in order for utility companies to recover fixed costs from shrinking sales bases. Increasing rates will, in turn, result in even more economic incentives for customers tomore » adopt rooftop PV. In this paper, we model this feedback between PV adoption and electricity rates and study its impact on future PV penetration and net-metering costs. We find that the most important parameter that determines whether this feedback has an effect is the fraction of customers who adopt PV in any year based solely on the money saved by doing so in that year, independent of the uncertainties of future years. These uncertainties include possible changes in rate structures such as the introduction of connection charges, the possibility of PV prices dropping significantly in the future, possible changes in tax incentives, and confidence in the reliability and maintainability of PV. (C) 2013 Elsevier Ltd. All rights reserved.« less

Ectopic transgene expression in the retina of four transgenic mouse lines

PubMed Central

Gábriel, Robert; Erdélyi, Ferenc; Szabó, Gábor; Lawrence, J. Josh

2017-01-01

Retinal expression of transgenes was examined in four mouse lines. Two constructs were driven by the choline acetyltransferase (ChAT) promoter: green fluorescent protein conjugated to tau protein (tau-GFP) or cytosolic yellow fluorescent protein (YFP) generated through CRE recombinase-induced expression of Rosa26 (ChAT-CRE/ Rosa26YFP). Two other constructs targeted inhibitory interneurons: GABAergic horizontal and amacrine cells identified by glutamic acid decarboxylase (GAD65-GFP) or parvalbumin (PV) cells (PV-CRE/Rosa26YFP). Animals were transcardially perfused and retinal sections prepared. Antibodies against PV, calretinin (CALR), calbindin (CALB), and tyrosine hydroxylase (TH) were used to counterstain transgene-expressing cells. In PVxRosa and ChAT-tauGFP constructs, staining appeared in vertically oriented row of processes resembling Müller cells. In the ChATxRosa construct, populations of amacrine cells and neurons in the ganglion cell layer were labeled. Some cones also exhibited GFP fluorescence. CALR, PV and TH were found in none of these cells. Occasionally, we found GFP/ CALR and GFP/PV double-stained cells in the ganglion cell layer (GCL). In the GAD65-GFP construct, all layers of the neuroretina were labeled, except photoreceptors. Not all horizontal cells expressed GFP. We did not find GFP/TH double-labeled cells and GFP was rarely present in CALR-and CALB-containing cells. Many PV-positive neurons were also labeled for GFP, including small diameter amacrines. In the GCL, single labeling for GFP and PV was ascertained, as well as several CALR/PV double-stained neurons. In the GCL, cells triple labeled with GFP/CALR/ CALB were sparse. In conclusion, only one of the four transgenic constructs exhibited an expression pattern consistent with endogenous retinal protein expression, while the others strongly suggested ectopic gene expression. PMID:26563404

Elevated Cholesterol in the Coxiella burnetii Intracellular Niche Is Bacteriolytic

PubMed Central

Mulye, Minal; Samanta, Dhritiman; Winfree, Seth; Heinzen, Robert A.

2017-01-01

ABSTRACT Coxiella burnetii is an intracellular bacterial pathogen and a significant cause of culture-negative endocarditis in the United States. Upon infection, the nascent Coxiella phagosome fuses with the host endocytic pathway to form a large lysosome-like vacuole called the parasitophorous vacuole (PV). The PV membrane is rich in sterols, and drugs perturbing host cell cholesterol homeostasis inhibit PV formation and bacterial growth. Using cholesterol supplementation of a cholesterol-free cell model system, we found smaller PVs and reduced Coxiella growth as cellular cholesterol concentration increased. Further, we observed in cells with cholesterol a significant number of nonfusogenic PVs that contained degraded bacteria, a phenotype not observed in cholesterol-free cells. Cholesterol had no effect on axenic Coxiella cultures, indicating that only intracellular bacteria are sensitive to cholesterol. Live-cell microscopy revealed that both plasma membrane-derived cholesterol and the exogenous cholesterol carrier protein low-density lipoprotein (LDL) traffic to the PV. To test the possibility that increasing PV cholesterol levels affects bacterial survival, infected cells were treated with U18666A, a drug that traps cholesterol in lysosomes and PVs. U18666A treatment led to PVs containing degraded bacteria and a significant loss in bacterial viability. The PV pH was significantly more acidic in cells with cholesterol or cells treated with U18666A, and the vacuolar ATPase inhibitor bafilomycin blocked cholesterol-induced PV acidification and bacterial death. Additionally, treatment of infected HeLa cells with several FDA-approved cholesterol-altering drugs led to a loss of bacterial viability, a phenotype also rescued by bafilomycin. Collectively, these data suggest that increasing PV cholesterol further acidifies the PV, leading to Coxiella death. PMID:28246364

Bactericidal Compounds Controlling Growth of the Plant Pathogen Pseudomonas syringae pv. actinidiae, Which Forms Biofilms Composed of a Novel Exopolysaccharide

PubMed Central

Ghods, Shirin; Sims, Ian M.; Moradali, M. Fata

2015-01-01

Pseudomonas syringae pv. actinidiae is the major cause of bacterial canker and is a severe threat to kiwifruit production worldwide. Many aspects of the disease caused by P. syringae pv. actinidiae, such as the pathogenicity-relevant formation of a biofilm composed of extracellular polymeric substances (EPSs), are still unknown. Here, a highly virulent strain of P. syringae pv. actinidiae, NZ V-13, was studied with respect to biofilm formation and architecture using a flow cell system combined with confocal laser scanning microscopy. The biofilm formed by P. syringae pv. actinidiae NZ V-13 was heterogeneous, consisting of a thin cellular base layer 5 μm thick and microcolonies with irregular structures. The major component of the EPSs produced by P. syringae pv. actinidiae NZ V-13 bacteria was isolated and identified to be an exopolysaccharide. Extensive compositional and structural analysis showed that rhamnose, fucose, and glucose were the major constituents, present at a ratio of 5:1.5:2. Experimental evidence that P. syringae pv. actinidiae NZ V-13 produces two polysaccharides, a branched α-d-rhamnan with side chains of terminal α-d-Fucf and an α-d-1,4-linked glucan, was obtained. The susceptibility of the cells in biofilms to kasugamycin and chlorine dioxide was assessed. About 64 and 73% of P. syringae pv. actinidiae NZ V-13 cells in biofilms were killed when kasugamycin and chlorine dioxide were used at 5 and 10 ppm, respectively. Kasugamycin inhibited the attachment of P. syringae pv. actinidiae NZ V-13 to solid surfaces at concentrations of 80 and 100 ppm. Kasugamycin was bacteriostatic against P. syringae pv. actinidiae NZ V-13 growth in the planktonic mode, with the MIC being 40 to 60 ppm and a bactericidal effect being found at 100 ppm. Here we studied the formation, architecture, and composition of P. syringae pv. actinidiae biofilms as well as used the biofilm as a model to assess the efficacies of bactericidal compounds. PMID:25841017

Research progress on organic-inorganic halide perovskite materials and solar cells

NASA Astrophysics Data System (ADS)

Ono, Luis K.; Qi, Yabing

2018-03-01

Owing to the intensive research efforts across the world since 2009, perovskite solar cell power conversion efficiencies (PCEs) are now comparable or even better than several other photovoltaic (PV) technologies. In this topical review article, we review recent progress in the field of organic-inorganic halide perovskite materials and solar cells. We associate these achievements with the fundamental knowledge gained in the perovskite research. The major recent advances in the fundamental perovskite material and solar cell research are highlighted, including the current efforts in visualizing the dynamical processes (in operando) taking place within a perovskite solar cell under operating conditions. We also discuss the existing technological challenges. Based on a survey of recently published works, we point out that to move the perovskite PV technology forward towards the next step of commercialization, what perovskite PV technology need the most in the coming next few years is not only further PCE enhancements, but also up-scaling, stability, and lead-toxicity.

Easy and fast method for expression and native extraction of Plasmodium vivax Duffy binding protein fragments.

PubMed

Moreno-Pérez, Darwin Andrés; Baquero, Luis Alfredo; Bermúdez, Maritza; Gómez-Muñoz, Laura Alejandra; Varela, Yahson; Patarroyo, Manuel Alfonso

2018-02-08

The Plasmodium vivax Duffy binding protein (PvDBP) has been the most studied ligand binding human reticulocytes to date. This molecule has a cysteine-rich domain in region II (RII) which has been used as control for evaluating the target cell binding activity of several parasite molecules. However, obtaining rPvDBP-RII in a soluble form using the Escherichia coli expression system usually requires laborious and time-consuming steps for recovering the molecule's structure and function, considering it is extracted from inclusion bodies. The present study describes an easy and fast method for expressing and obtaining several PvDBP fragments which should prove ideal for use in protein-cell interaction assays. Two PvDBP encoding regions (rii and riii/v) were cloned in pEXP5-CT vector and expressed in E. coli and extracted from the soluble fraction (rPvDBP-RII S and rPvDBP-RIII/V S ) using a simple freezing/thawing protocol. After the purification, dichroism analysis enabled verifying high rPvDBP-RII S and rPvDBP-RIII/V S secondary structure α-helix content, which was lowered when molecules were extracted from inclusion bodies (rPvDBP-RII IB and rPvDBP-RIII/V IB ) using a denaturing step. Interestingly, rPvDBP-RII S , but not rPvDBP-RII IB , bound to human reticulocytes, while rPvDBP-RIII/V S and rPvDBP-RIII/V IB bound to such cells in a similar way to negative control (cells incubated without recombinant proteins). This research has shown for the first time how rPvDBP-RII can be expressed and obtained in soluble form using the E. coli system and avoiding the denaturation and refolding steps commonly used. The results highlight the usefulness of the rPvDBP-RIII/V S fragment as a non-binding control for protein-cell target interaction assays. The soluble extraction protocol described is a good alternative to obtain fully functional P. vivax proteins in a fast and easy way, which will surely prove useful to laboratories working in studying this parasite's biology.

Practical design considerations for photovoltaic power station

NASA Astrophysics Data System (ADS)

Swanson, T. D.

Aspects of photovoltaic (PV) technology are discussed along with generic PV design considerations, taking into account the resource sunlight, PV modules and their reliability, questions of PV system design, the support structure subsystem, and a power conditioning unit subsystem. A description is presented of two recent projects which demonstrate the translation of an idea into actual working PV systems. A privately financed project in Denton, Maryland, went on line in early December, 1982, and began providing power to the local utility grid. It represents the first intermediate size, grid-connected, privately financed power station in the U.S. Based on firm quotes, the actual cost of this system is about $13/W peak. The other project, called the PV Breeder, is an energy independent facility which utilizes solar power to make new solar cells. It is also the first large industrial structure completely powered by the sun.

Differential induction of Toll-like receptors & type 1 interferons by Sabin attenuated & wild type 1 polioviruses in human neuronal cells.

PubMed

Mohanty, Madhu C; Deshpande, Jagadish M

2013-01-01

Polioviruses are the causative agent of paralytic poliomyelitis. Attenuated polioviruses (Sabin oral poliovirus vaccine strains) do not replicate efficiently in neurons as compared to the wild type polioviruses and therefore do not cause disease. This study was aimed to investigate the differential host immune response to wild type 1 poliovirus (wild PV) and Sabin attenuated type 1 poliovirus (Sabin PV) in cultured human neuronal cells. By using flow cytometry and real time PCR methods we examined host innate immune responses and compared the role of toll like receptors (TLRs) and cytoplasmic RNA helicases in cultured human neuronal cells (SK-N-SH) infected with Sabin PV and wild PV. Human neuronal cells expressed very low levels of TLRs constitutively. Sabin PV infection induced significantly higher expression of TLR3, TLR7 and melanoma differentiation-associated protein-5 (MDA-5) m-RNA in neuronal cells at the beginning of infection (up to 4 h) as compared to wild PV. Further, Sabin PV also induced the expression of interferon α/β at early time point of infection. The induced expression of IFN α/β gene by Sabin PV in neuronal cells could be suppressed by inhibiting TLR7. Neuronal cell innate immune response to Sabin and wild polioviruses differ significantly for TLR3, TLR7, MDA5 and type 1 interferons. Effects of TLR7 activation and interferon production and Sabin virus replication in neuronal cells need to be actively investigated in future studies.

A Fundamental Study on Spectrum Center Estimation of Solar Spectral Irradiation by the Statistical Pattern Recognition

NASA Astrophysics Data System (ADS)

Iijima, Aya; Suzuki, Kazumi; Wakao, Shinji; Kawasaki, Norihiro; Usami, Akira

With a background of environmental problems and energy issues, it is expected that PV systems will be introduced rapidly and connected with power grids on a large scale in the future. For this reason, the concern to which PV power generation will affect supply and demand adjustment in electric power in the future arises and the technique of correctly grasping the PV power generation becomes increasingly important. The PV power generation depends on solar irradiance, temperature of a module and solar spectral irradiance. Solar spectral irradiance is distribution of the strength of the light for every wavelength. As the spectrum sensitivity of solar cell depends on kind of solar cell, it becomes important for exact grasp of PV power generation. Especially the preparation of solar spectral irradiance is, however, not easy because the observational instrument of solar spectral irradiance is expensive. With this background, in this paper, we propose a new method based on statistical pattern recognition for estimating the spectrum center which is representative index of solar spectral irradiance. Some numerical examples obtained by the proposed method are also presented.

SMART empirical approaches for predicting field performance of PV modules from results of reliability tests

NASA Astrophysics Data System (ADS)

Hardikar, Kedar Y.; Liu, Bill J. J.; Bheemreddy, Venkata

2016-09-01

Gaining an understanding of degradation mechanisms and their characterization are critical in developing relevant accelerated tests to ensure PV module performance warranty over a typical lifetime of 25 years. As newer technologies are adapted for PV, including new PV cell technologies, new packaging materials, and newer product designs, the availability of field data over extended periods of time for product performance assessment cannot be expected within the typical timeframe for business decisions. In this work, to enable product design decisions and product performance assessment for PV modules utilizing newer technologies, Simulation and Mechanism based Accelerated Reliability Testing (SMART) methodology and empirical approaches to predict field performance from accelerated test results are presented. The method is demonstrated for field life assessment of flexible PV modules based on degradation mechanisms observed in two accelerated tests, namely, Damp Heat and Thermal Cycling. The method is based on design of accelerated testing scheme with the intent to develop relevant acceleration factor models. The acceleration factor model is validated by extensive reliability testing under different conditions going beyond the established certification standards. Once the acceleration factor model is validated for the test matrix a modeling scheme is developed to predict field performance from results of accelerated testing for particular failure modes of interest. Further refinement of the model can continue as more field data becomes available. While the demonstration of the method in this work is for thin film flexible PV modules, the framework and methodology can be adapted to other PV products.

Pemphigus vulgaris: accumulation of apoptotic cells in dermis and epidermis possibly relates to pathophysiology through TNF-alpha production by phagocytes.

PubMed

Chiapa-Labastida, Mariana; Zentella-Dehesa, Alejandro; León-Dorantes, Gladys; Becker, Ingeborg

2011-01-01

Apoptotic cells are present in the epidermis of pemphigus vulgaris (PV) patients and their accumulation has been linked to chronic inflammatory disorders. TNF-α is elevated in sera of PV patients and has only been detected in acantholytic and periacantholytic keratinocytes (KC), therefore another TNF-α source might exist. We analyzed, in lesional and perilesional skin of 5 active untreated PV patients, the presence of apoptotic cells, TNF-α and phagocytic infiltrate. In vitro, we analyzed whether phagocytosis of apoptotic KCs by monocytes causes TNF-α release. We found a significant increase of apoptotic cells in the epidermis and dermis of PV patients, by TUNEL, and activated caspase-3. TNF-α was present in the skin of PV patients, especially in the dermis. Phagocytic CD14+ cells were increased, mostly in the dermis of PV patients. In vitro phagocytosis of apoptotic KCs by monocytes caused enhanced TNF-α production, which correlated with the number of apoptotic KCs in the co-culture. Thus, accumulation of apoptotic cells in PV could promote TNF-α production by monocytes, which could, in turn, cause further apoptosis, closing a vicious circle.

A probabilistic approach to photovoltaic generator performance prediction

NASA Astrophysics Data System (ADS)

Khallat, M. A.; Rahman, S.

1986-09-01

A method for predicting the performance of a photovoltaic (PV) generator based on long term climatological data and expected cell performance is described. The equations for cell model formulation are provided. Use of the statistical model for characterizing the insolation level is discussed. The insolation data is fitted to appropriate probability distribution functions (Weibull, beta, normal). The probability distribution functions are utilized to evaluate the capacity factors of PV panels or arrays. An example is presented revealing the applicability of the procedure.

Breakdown voltage mapping through voltage dependent ReBEL intensity imaging of multi-crystalline Si solar cells

NASA Astrophysics Data System (ADS)

Dix-Peek, RM.; van Dyk, EE.; Vorster, FJ.; Pretorius, CJ.

2018-04-01

Device material quality affects both the efficiency and the longevity of photovoltaic (PV) cells. Therefore, identifying these defects can be beneficial in the development of more efficient and longer lasting PV cells. In this study, a combination of spatially-resolved, electroluminescence (EL), and light beam induced current (LBIC) measurements, were used to identify specific defects and features of a multi-crystalline Si PV cells. In this study, a novel approach is used to map the breakdown voltage of a PV cell through voltage dependent Reverse Bias EL (ReBEL) intensity imaging.

Progress of the Photovoltaic Technology Incubator Project Towards an Enhanced U.S. Manufacturing Base: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ullal, H.; Mitchell, R.; Keyes, B.

In this paper, we report on the major accomplishments of the U.S. Department of Energy's (DOE) Solar Energy Technologies Program (SETP) Photovoltaic (PV) Technology Incubator project. The Incubator project facilitates a company's transition from developing a solar cell or PV module prototype to pilot- and large-scale U.S. manufacturing. The project targets small businesses that have demonstrated proof-of-concept devices or processes in the laboratory. Their success supports U.S. Secretary of Energy Steven Chu's SunShot Initiative, which seeks to achieve PV technologies that are cost-competitive without subsidies at large scale with fossil-based energy sources by the end of this decade. The Incubatormore » Project has enhanced U.S. PV manufacturing capacity and created more than 1200 clean energy jobs, resulting in an increase in American economic competitiveness. The investment raised to date by these PV Incubator companies as a result of DOE's $ 59 million investment totals nearly $ 1.3 billion.« less

Air-dried cells from the anhydrobiotic insect, Polypedilum vanderplanki, can survive long term preservation at room temperature and retain proliferation potential after rehydration.

PubMed

Watanabe, Kazuyo; Imanishi, Shigeo; Akiduki, Gaku; Cornette, Richard; Okuda, Takashi

2016-08-01

Pv11, a cell line derived from the anhydrobiotic insect, Polypedilum vanderplanki, was preserved in a dry form (only 6% residual moisture) at room temperature for up to 251 days and restarted proliferating after rehydration. A previous study already reported survival of Pv11 cells after desiccation, but without subsequent proliferation. Here, the protocol was improved to increase survival and achieve proliferation of Pv11 cells after dry storage. The method basically included preincubation, desiccation and rehydration processes and each step was investigated. So far, preincubation in a 600 mM trehalose solution for 48 h before dehydration was the most favourable preconditioning to achieve successful dry preservation of Pv11 cells, allowing about 16% of survival after rehydration and subsequent cell proliferation. Although the simple air-dry method established for Pv11 cells here was not applicable for successful dry-preservation of other insect cell lines, Pv11 is the first dry-preservable animal cell line and will surely contribute not only to basic but also applied sciences. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

75 FR 52322 - Nationwide Limited Public Interest Waiver Under Section 1605 (Buy American) of the American...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-25

... ancillary solar Photovoltaic (PV) equipment, when this equipment is utilized in solar installations... following solar PV equipment: (1) Domestically- manufactured modules containing foreign-manufactured cells... effect. Solar cells are the basic building block of PV technologies. The cells are functional...

Photon harvesting, coloring and polarizing in photovoltaic cell integrated color filters: efficient energy routing strategies for power-saving displays.

PubMed

Wen, Long; Chen, Qin; Song, Shichao; Yu, Yan; Jin, Lin; Hu, Xin

2015-07-03

We describe the integral electro-optical strategies that combine the functionalities of photovoltaic (PV) electricity generation and color filtering as well as polarizing to realize more efficient energy routing in display technology. Unlike the conventional pigment-based filters and polarizers, which absorb substantial amounts of unwanted spectral components and dissipate them in the form of heat, we propose converting the energy of those photons into electricity by constructing PV cell-integrated color filters based on a selectively transmitting aluminum (Al) rear electrode perforated with nanoholes (NHs). Combining with a dielectric-metal-dielectric (DMD) front electrode, the devices were optimized to enable efficient cavity-enhanced photon recycling in the PV functional layers. We perform a comprehensive theoretical and numerical analysis to explore the extraordinary optical transmission (EOT) through the Al NHs and identify basic design rules for achieving structural coloring or polarizing in our PV color filters. We show that the addition of thin photoactive polymer layers on the symmetrically configured Al NH electrode narrows the bandwidth of the EOT-assisted high-pass light filtering due to the strongly damped anti-symmetric coupling of the surface modes excited on the front and rear surface of the Al NHs, which facilitates the whole visible coloring with relatively high purity for the devices. By engineering the cut-off characteristics of the plasmonic waveguide mode supported by the circular or ellipsoidal Al NHs, beyond the photon recycling capacity, PV color filters and PV polarizing color filters that allow polarization-insensitive and strong polarization-anisotropic color filtering were demonstrated. The findings presented here may shed some light on expanding the utilization of PV electricity generation across new-generation energy-saving electrical display devices.

Advances in Plexcore active layer technology systems for organic photovoltaics: roof-top and accelerated lifetime analysis of high performance organic photovoltaic cells

NASA Astrophysics Data System (ADS)

Laird, Darin W.; Vaidya, Swanand; Li, Sergey; Mathai, Mathew; Woodworth, Brian; Sheina, Elena; Williams, Shawn; Hammond, Troy

2007-09-01

We report NREL-certified efficiencies and initial lifetime data for organic photovoltaic (OPV) cells based on Plexcore PV photoactive layer and Plexcore HTL-OPV hole transport layer technology. Plexcore PV-F3, a photoactive layer OPV ink, was certified in a single-layer OPV cell at the National Renewable Energy Laboratory (NREL) at 5.4%, which represents the highest official mark for a single-layer organic solar cell. We have fabricated and measured P3HT:PCBM solar cells with a peak efficiency of 4.4% and typical efficiencies of 3 - 4% (internal, NREL-calibrated measurement) with P3HT manufactured at Plextronics by the Grignard Metathesis (GRIM) method. Outdoor and accelerated lifetime testing of these devices is reported. Both Plexcore PV-F3 and P3HT:PCBM-based OPV cells exhibit >750 hours of outdoor roof-top, non-accelerated lifetime with less than 8% loss in initial efficiency for both active layer systems when exposed continuously to the climate of Western Pennsylvania. These devices are continuously being tested to date. Accelerated testing using a high-intensity (1000W) metal-halide lamp affords shorter lifetimes; however, the true acceleration factor is still to be determined.

Power Budget Analysis for High Altitude Airships

NASA Technical Reports Server (NTRS)

Choi, Sang H.; Elliott, James R.; King, Glen C.

2006-01-01

The High Altitude Airship (HAA) has various potential applications and mission scenarios that require onboard energy harvesting and power distribution systems. The energy source considered for the HAA s power budget is solar photon energy that allows the use of either photovoltaic (PV) cells or advanced thermoelectric (ATE) converters. Both PV cells and an ATE system utilizing high performance thermoelectric materials were briefly compared to identify the advantages of ATE for HAA applications in this study. The ATE can generate a higher quantity of harvested energy than PV cells by utilizing the cascaded efficiency of a three-staged ATE in a tandem mode configuration. Assuming that each stage of ATE material has the figure of merit of 5, the cascaded efficiency of a three-staged ATE system approaches the overall conversion efficiency greater than 60%. Based on this estimated efficiency, the configuration of a HAA and the power utility modules are defined.

CD28 T-cell costimulatory molecule expression in pemphigus vulgaris.

PubMed

Alecu, M; Ursaciuc, C; Surcel, M; Coman, G; Ciotaru, D; Dobre, M

2009-03-01

CD28 superfamily of immune costimulatory molecules could play an important role in autotolerance control. CD28 costimulation seems to be necessary for regulatory T cell (Treg) activation and successive suppressive activities involved in autoimmunity protection. This study investigates CD28 expression, especially inducible costimulator fraction, on T lymphocytes in pemphigus vulgaris (PV) patients. CD28 expression on T lymphocytes was assessed in 16 PV patients during acute attack. All patients and 10 healthy control subjects were tested for lymphocyte populations, T-cell subpopulations (T-CD4+, T-CD8+), Treg and CD28 expression on T-cell subpopulations. T, B and natural killer cells average values in PV patients were close to the control group values. Compared with control group, PV values showed lower Treg (2.2% compared with 4.7%), slightly decreased CD4+ CD28+ T cells (91% compared with 95%), higher CD4+ CD28- T cells (9% compared with 5%), decreased CD8+ CD28+ T cells (57% and 73%, respectively) and significantly enhanced CD8+ CD28- T cells (43% compared with 27%). These data suggest that Treg-mediated suppressor T-cell effects could be diminished in PV, together with an abnormal or ineffective subsequent helper T-cell suppression. CD28 high expression on helper T cells and low expression on suppressor T cells are arguments for a potential CD28 role in PV autoimmune response mechanism.

Sarah Kurtz | NREL

Science.gov Websites

next stage of growth for the PV industry. Participated in the demonstration of the GaInP/GaAs solar photovoltaics (PV), concentrator PV, and PV reliability. Kurtz and NREL colleague Jerry Olson championed the early use of multi-junction solar cells by showing that a top cell of gallium indium phosphide (GaInP

Photovoltaics: Energy for the New Millenium

NASA Astrophysics Data System (ADS)

Surek, Thomas

2000-04-01

Photovoltaics (PV) is a semiconductor-based technology that directly converts sunlight to electricity. The stimulus for terrestrial PV started more than 25 years ago in response to the oil crises of the 1970s, which resulted in major government programs in the United States, Europe, Japan, and elsewhere. Ongoing concerns with the global environment, as well as the worldwide efforts to seek alternate, indigenous sources of energy, continue to drive the investment in PV research and deployment. Today, the manufacture, sale, and use of PV has become a billion-dollar industry worldwide, with nearly 200 megawatts (MW) of PV modules shipped in 1999. The twenty five years of research and development led to the discovery of new PV materials, devices, and fabrication approaches; continuing improvements in the efficiency and reliability of solar cells and modules; and lower PV module and system costs. This talk reviews the rapid progress that has occurred in PV technology from the laboratory to the marketplace, including reviews of the leading technology options, status and issues, and key industry players. New processes for fabricating PV materials and devices, and innovative PV approaches with low-cost potential are elements of an ongoing research program aimed at future advancements in PV cost and performance While major market opportunities continue to exist in the developing countries, where sizable populations are without any electricity, today's manufacturing expansions are fueled by market initiatives for grid-connected PV in residential and commercial buildings. The combinations of increased production capacities, with the attendant cost reductions as a result of economies of scale, are expected to lead to sustainable markets. A key to achieving the ultimate potential of PV is to continue to increase the sunlight-to-electricity conversion efficiencies and translate the laboratory successes to cost-competitive products. Building a robust technology base is essential to overcoming this high-risk transition. Then PV will make a globally significant contribution to our energy supply and environment.

Three junction holographic micro-scale PV system

NASA Astrophysics Data System (ADS)

Wu, Yuechen; Vorndran, Shelby; Ayala Pelaez, Silvana; Kostuk, Raymond K.

2016-09-01

In this work a spectrum splitting micro-scale concentrating PV system is evaluated to increase the conversion efficiency of flat panel PV systems. In this approach, the dispersed spectrum splitting concentration systems is scaled down to a small size and structured in an array. The spectrum splitting configuration allows the use of separate single bandgap PV cells that increase spectral overlap with the incident solar spectrum. This results in an overall increase in the spectral conversion efficiency of the resulting system. In addition other benefits of the micro-scale PV system are retained such reduced PV cell material requirements, more versatile interconnect configurations, and lower heat rejection requirements that can lead to a lower cost system. The system proposed in this work consists of two cascaded off-axis holograms in combination with a micro lens array, and three types of PV cells. An aspherical lens design is made to minimize the dispersion so that higher concentration ratios can be achieved for a three-junction system. An analysis methodology is also developed to determine the optical efficiency of the resulting system, the characteristics of the dispersed spectrum, and the overall system conversion efficiency for a combination of three types of PV cells.

Reduction in cortical parvalbumin expression due to intermittent theta-burst stimulation correlates with maturation of the perineuronal nets in young rats.

PubMed

Mix, Annika; Hoppenrath, Kathrin; Funke, Klaus

2015-01-01

We recently showed that intermittent theta-burst stimulation (iTBS) using transcranial magnetic stimulation strongly reduces the number of rat neocortical interneurons expressing glutamic acid decarboxylase 67 kDa (GAD67) and parvalbumin (PV), indicating changed activity of fast-spiking (FS) interneurons. In advance of in vitro studies intended to characterize changes in electrical properties of FS interneurons under these conditions, we tested whether the iTBS effect is age-dependent. Conscious Sprague-Dawley rats aged between 28 and 90 days received three blocks of iTBS at 15 min intervals. We found that iTBS-related reduction in PV+ cells was absent up to an age of 32 days, then gradually increased, and approached a maximum of about 40% reduction at an age of about 40 days. The relative number of cells expressing PV (PV+, 8-9%) did not change with age in sham-controls and also the increase in cortical c-Fos expression induced by iTBS was not principally age-dependent. However, a prominent growth of the perineuronal nets, typically surrounding the PV+ cells, exactly paralleled the increase in the iTBS effect. Based on these findings, we conclude that the functional development of the inhibitory network of PV+ interneurons with regard to intracortical synaptic connectivity is not sufficiently matured in rats younger than 35 d to enable activity-dependent modifications during iTBS. Outgrowth of the perineuronal nets and associated maturation of excitatory cortical inputs, as is characteristic for the critical cortical period, may take place before PV+ interneurons can be sufficiently activated via repetitive transcranial magnetic stimulation, allowing plastic changes of molecular phenotype and likely also synaptic plasticity. © 2014 Wiley Periodicals, Inc.

Phenotypic variability within the JAK2 V617F-positive MPD: The roles of progenitor cell and neutrophil allele burdens

PubMed Central

Moliterno, Alison R.; Williams, Donna M.; Rogers, Ophelia; Isaacs, Mary Ann; Spivak, Jerry L.

2008-01-01

(1) Objective The myeloproliferative disorders (MPD), polycythemia vera (PV), essential thrombocytosis (ET) and primary myelofibrosis (PMF) differ phenotypically but share the same JAK2V617F mutation. We examined the relationship of the quantitative JAK2V617F allele burden to MPD disease phenotype among the three MPD classes and within PV. (2) Methods We measured the JAK2V617F allele percentage in genomic DNA from neutrophils, CD34+ cells, and cloned progenitors in 212 JAK2V617F –positive MPD patients and correlated the allele burdens to both disease class and disease features. (3) Results In ET and PV, the mean CD34+ cell JAK2V617F allele burdens were lower than the corresponding neutrophil allele burdens, but these were equivalent in PMF. JAK2WT progenitors were present in ET and PV when the CD34+ JAK2V617F allele burden was lower than the neutrophil allele burden, but not in PV and PMF subjects in whom the CD34+ cell and neutrophil allele burdens were similar. CD34+ cell JAK2V617F clonal dominance, defined as coherence between the CD34+ cell and neutrophil JAK2V617F allele burdens, was present in 24% of ET, 56% of PV and 93% of PMF patients, and was independent of the CD34+ cell JAK2V617F genotype. Clonally-dominant PV patients had significantly longer disease durations, higher white cell counts and larger spleens than nondominant PV patients. (4) Conclusions We conclude that the extent of JAK2V617F CD34+ cell clonal dominance is associated with disease phenotype within the MPD, and in PV, is associated with extramedullary disease, leukocytosis and disease duration. PMID:18723264

Service lifetime prediction for encapsulated photovoltaic cells/minimodules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Czanderna, A.W.; Jorgensen, G.J.

The overall purposes of this paper are to elucidate the crucial importance of predicting the service lifetime (SLP) for photovoltaics (PV) modules and to present an outline for developing a SLP methodology for encapsulated PV cells and minimodules. The specific objectives are (a) to illustrate the generic nature of SLP for several types of solar energy conversion or conversion devices, (b) to summarize the major durability issues concerned with these devices, (c) to justify using SLP in the triad of cost, performance, and durability instead of only durability, (d) to define and explain the seven major elements that comprise amore » generic SLP methodology, (e) to provide background about implementing the SLP methodology for PV cells and minimodules including the complexity of the encapsulation problems, (f) to summarize briefly the past focus of our task for improving and/or replacing ethylene vinyl acetate (EVA) as a PV pottant, and (g) to provide an outline of our present and future studies using encapsulated PV cells and minimodules for improving the encapsulation of PV cells and predicting a service lifetime for them using the SLP methodology outlined in objective (d). By using this methodology, our major conclusion is that predicting the service lifetime of PV cells and minimodules is possible. {copyright} {ital 1997 American Institute of Physics.}« less

Development of Deposition and Characterization Systems for Thin Film Solar Cells

NASA Astrophysics Data System (ADS)

Cimaroli, Alexander J.

Photovoltaic (PV) devices are becoming more important due to a number of economic and environmental factors. PV research relies on the ability to quickly fabricate and characterize these devices. While there are a number of deposition methods that are available in a laboratory setting, they are not necessarily able to be scaled to provide high throughput in a commercial setting. A close-space sublimation (CSS) system was developed to provide a means of depositing thin films in a very controlled and scalable manner. Its viability was explored by using it to deposit the absorber layer in Zn3P2 and CdTe solar cell devices. Excellent control over morphology and growth conditions and a high level of repeatability was demonstrated in the study of textured Zn3P2 thin films. However, some limitations imposed by the structure of Zn3P 2-based PV devices showed that CSS may not be the best approach for depositing Zn3P2 thin films. Despite the inability to make Zn3P2 solar cell devices, high efficiency CdTe solar cells were fabricated using CSS. With the introduction of Perovskite-based solar cell devices, the viability of data collected from conventional J-V measurements was questioned due to the J-V hysteresis that Perovskite devices exhibited. New methods of solar cell characterization were developed in order to accurately and quickly assess the performance of hysteretic PV devices. Both J-V measurements and steady-state efficiency measurements are prone to errors due to hysteresis and maximum power point drift. To resolve both of these issues, a maximum power point tracking (MPPT) system was developed with two algorithms: a simple algorithm and a predictive algorithm. The predictive algorithm showed increased resistance to the effects of hysteresis because of its ability to predict the steady-state current after a bias step with a double exponential decay model fit. Some publications have attempted to quantify the degree of J-V hysteresis present in fabricated Perovskite-based devices, but the analysis relied on J-V measurements. The sweep rate, starting bias, illumination time, etc. would affect the value of the calculated degree of hysteresis. A method of using transient photocurrent measurements is presented to accurately quantify the degree of hysteresis for all solar cells: not just Perovskite-based devices. According to this method, almost all solar cell devices exhibit several forms of J-V hysteresis. This method may open new ways of analyzing the defects in fabricated PV devices.

Distinct Thalamic Reticular Cell Types Differentially Modulate Normal and Pathological Cortical Rhythms.

PubMed

Clemente-Perez, Alexandra; Makinson, Stefanie Ritter; Higashikubo, Bryan; Brovarney, Scott; Cho, Frances S; Urry, Alexander; Holden, Stephanie S; Wimer, Matthew; Dávid, Csaba; Fenno, Lief E; Acsády, László; Deisseroth, Karl; Paz, Jeanne T

2017-06-06

Integrative brain functions depend on widely distributed, rhythmically coordinated computations. Through its long-ranging connections with cortex and most senses, the thalamus orchestrates the flow of cognitive and sensory information. Essential in this process, the nucleus reticularis thalami (nRT) gates different information streams through its extensive inhibition onto other thalamic nuclei, however, we lack an understanding of how different inhibitory neuron subpopulations in nRT function as gatekeepers. We dissociated the connectivity, physiology, and circuit functions of neurons within rodent nRT, based on parvalbumin (PV) and somatostatin (SOM) expression, and validated the existence of such populations in human nRT. We found that PV, but not SOM, cells are rhythmogenic, and that PV and SOM neurons are connected to and modulate distinct thalamocortical circuits. Notably, PV, but not SOM, neurons modulate somatosensory behavior and disrupt seizures. These results provide a conceptual framework for how nRT may gate incoming information to modulate brain-wide rhythms. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Effect of power system technology and mission requirements on high altitude long endurance aircraft

NASA Technical Reports Server (NTRS)

Colozza, Anthony J.

1994-01-01

An analysis was performed to determine how various power system components and mission requirements affect the sizing of a solar powered long endurance aircraft. The aircraft power system consists of photovoltaic cells and a regenerative fuel cell. Various characteristics of these components, such as PV cell type, PV cell mass, PV cell efficiency, fuel cell efficiency, and fuel cell specific mass, were varied to determine what effect they had on the aircraft sizing for a given mission. Mission parameters, such as time of year, flight altitude, flight latitude, and payload mass and power, were also altered to determine how mission constraints affect the aircraft sizing. An aircraft analysis method which determines the aircraft configuration, aspect ratio, wing area, and total mass, for maximum endurance or minimum required power based on the stated power system and mission parameters is presented. The results indicate that, for the power system, the greatest benefit can be gained by increasing the fuel cell specific energy. Mission requirements also substantially affect the aircraft size. By limiting the time of year the aircraft is required to fly at high northern or southern latitudes, a significant reduction in aircraft size or increase in payload capacity can be achieved.

Broadband Gerchberg-Saxton algorithm for freeform diffractive spectral filter design.

PubMed

Vorndran, Shelby; Russo, Juan M; Wu, Yuechen; Pelaez, Silvana Ayala; Kostuk, Raymond K

2015-11-30

A multi-wavelength expansion of the Gerchberg-Saxton (GS) algorithm is developed to design and optimize a surface relief Diffractive Optical Element (DOE). The DOE simultaneously diffracts distinct wavelength bands into separate target regions. A description of the algorithm is provided, and parameters that affect filter performance are examined. Performance is based on the spectral power collected within specified regions on a receiver plane. The modified GS algorithm is used to design spectrum splitting optics for CdSe and Si photovoltaic (PV) cells. The DOE has average optical efficiency of 87.5% over the spectral bands of interest (400-710 nm and 710-1100 nm). Simulated PV conversion efficiency is 37.7%, which is 29.3% higher than the efficiency of the better performing PV cell without spectrum splitting optics.

MPPT Algorithm Development for Laser Powered Surveillance Camera Power Supply Unit

NASA Astrophysics Data System (ADS)

Zhang, Yungui; Dushantha Chaminda, P. R.; Zhao, Kun; Cheng, Lin; Jiang, Yi; Peng, Kai

2018-03-01

Photovoltaics (PV) cells, modules which are semiconducting materials, convert light energy into electricity. Operation of a PV cell requires 3 basic features. When the light is absorbed it generate pairs of electron holes or excitons. An external circuit carrier opposite types of electrons irrespective of the source (sunlight or LASER light). The PV arrays have photovoltaic effect and the PV cells are defined as a device which has electrical characteristics: such as current, voltage and resistance. It varies when exposed to light, that the power output is depend on direct Laser-light. In this paper Laser-light to electricity by direct conversion with the use of PV cells and its concept of Band gap Energy, Series Resistance, Conversion Efficiency and Maximum Power Point Tracking (MPPT) methods [1].

Solar-powered unmanned aerial vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reinhardt, K.C.; Lamp, T.R.; Geis, J.W.

1996-12-31

An analysis was performed to determine the impact of various power system components and mission requirements on the size of solar-powered high altitude long endurance (HALE)-type aircraft. The HALE unmanned aerial vehicle (UAV) has good potential for use in many military and civil applications. The primary power system components considered in this study were photovoltaic (PV) modules for power generation and regenerative fuel cells for energy storage. The impact of relevant component performance on UAV size and capability were considered; including PV module efficiency and mass, power electronics efficiency, and fuel cell specific energy. Mission parameters such as time ofmore » year, flight altitude, flight latitude, and payload mass and power were also varied to determine impact on UAV size. The aircraft analysis method used determines the required aircraft wing aspect ratio, wing area, and total mass based on maximum endurance or minimum required power calculations. The results indicate that the capacity of the energy storage system employed, fuel cells in this analysis, greatly impacts aircraft size, whereas the impact of PV module efficiency and mass is much less important. It was concluded that an energy storage specific energy (total system) of 250--500 Whr/kg is required to enable most useful missions, and that PV cells with efficiencies greater than {approximately} 12% are suitable for use.« less

Virotherapy of digestive tumors with rodent parvovirus: overview and perspectives.

PubMed

Akladios, Cherif; Aprahamian, Marc

2016-01-01

Toolan's H-1 parvovirus (H-1PV) exerts a cytotoxic/oncolytic effect, predominantly mediated by its non-structural protein (NS1). This rat parvovirus is harmless, unlike other parvoviruses, and its antitumor potential may be useful to clinicians as its oncolytic action appears to be true in numerous non-digestive and digestive cancers. After a brief review of parvovirus genus and biology, we summarize the proposed mechanisms to explain the cytotoxicity of H-1PV to tumors which results in dysregulation of cell transcription, cell-cycle arrest, termination of cell replication, activation of cellular stress response and induction of cell death. Viral oncolysis induces a strong tumor-specific immune response leading to the recognition and elimination of minimal residual disease. As the action of H-1PV is not limited to the digestive tract, we initially analyse studies performed in non-digestive cancers such as glioma (as the virus is able to cross the blood brain barrier), and then focused more particularly on the results in digestive cancers. Based on the results of studies showing little H-1PV toxicity to living bodies, we advocate for the use of the parvovirus in cancers such as melanoma, glioma and pancreatic ductal adenocarcinoma in addition to conventional chemotherapy.

Rapid disinhibition by adjustment of PV intrinsic excitability during whisker map plasticity in mouse S1.

PubMed

Gainey, Melanie A; Aman, Joseph W; Feldman, Daniel E

2018-04-20

Rapid plasticity of layer (L) 2/3 inhibitory circuits is an early step in sensory cortical map plasticity, but its cellular basis is unclear. We show that, in mice of either sex, 1 day whisker deprivation drives rapid loss of L4-evoked feedforward inhibition and more modest loss of feedforward excitation in L2/3 pyramidal (PYR) cells, increasing E-I conductance ratio. Rapid disinhibition was due to reduced L4-evoked spiking by L2/3 parvalbumin (PV) interneurons, caused by reduced PV intrinsic excitability. This included elevated PV spike threshold, associated with an increase in low-threshold, voltage activated delayed rectifier (presumed Kv1) and A-type potassium currents. Excitatory synaptic input and unitary inhibitory output of PV cells were unaffected. Functionally, the loss of feedforward inhibition and excitation were precisely coordinated in L2/3 PYR cells, so that peak feedforward synaptic depolarization remained stable. Thus, rapid plasticity of PV intrinsic excitability offsets early weakening of excitatory circuits to homeostatically stabilize synaptic potentials in PYR cells of sensory cortex. SIGNIFICANCE STATEMENT Inhibitory circuits in cerebral cortex are highly plastic, but the cellular mechanisms and functional importance of this plasticity are incompletely understood. We show that brief (1-day) sensory deprivation rapidly weakens parvalbumin (PV) inhibitory circuits by reducing the intrinsic excitability of PV neurons. This involved a rapid increase in voltage-gated potassium conductances that control near-threshold spiking excitability. Functionally, the loss of PV-mediated feedforward inhibition in L2/3 pyramidal cells was precisely balanced with the separate loss of feedforward excitation, resulting in a net homeostatic stabilization of synaptic potentials. Thus, rapid plasticity of PV intrinsic excitability implements network-level homeostasis to stabilize synaptic potentials in sensory cortex. Copyright © 2018 the authors.

Solar concentrator modules with silicone-onglass Fresnel lens panels and multijunction cells.

PubMed

Rumyantsev, Valery D

2010-04-26

High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute. The approach to R&D of the solar PV modules is based on the concepts of sunlight concentration by small-aperture area Fresnel lenses and "all-glass" module design. The small-aperture area lenses are arranged as a panel with silicone-on-glass structure where the glass plate serves as the front surface of a module. In turn, high-efficiency InGaP/(In)GaAs/Ge cells are arranged on a rear module panel mounted on a glass plate which functions as a heat sink and integrated protective cover for the cells. The developed PV modules and sun trackers are characterized by simple design, and are regarded as the prototypes for further commercialization.

Holographic spectrum-splitting optical systems for solar photovoltaics

NASA Astrophysics Data System (ADS)

Zhang, Deming

Solar energy is the most abundant source of renewable energy available. The relatively high cost prevents solar photovoltaic (PV) from replacing fossil fuel on a larger scale. In solar PV power generation the cost is reduced with more efficient PV technologies. In this dissertation, methods to improve PV conversion efficiency with holographic optical components are discussed. The tandem multiple-junction approach has achieved very high conversion efficiency. However it is impossible to manufacture tandem PV cells at a low cost due to stringent fabrication standards and limited material types that satisfy lattice compatibility. Current produced by the tandem multi-junction PV cell is limited by the lowest junction due to series connection. Spectrum-splitting is a lateral multi-junction concept that is free of lattice and current matching constraints. Each PV cell can be optimized towards full absorption of a spectral band with tailored light-trapping schemes. Holographic optical components are designed to achieve spectrum-splitting PV energy conversion. The incident solar spectrum is separated onto multiple PV cells that are matched to the corresponding spectral band. Holographic spectrum-splitting can take advantage of existing and future low-cost technologies that produces high efficiency thin-film solar cells. Spectrum-splitting optical systems are designed and analyzed with both transmission and reflection holographic optical components. Prototype holograms are fabricated and high optical efficiency is achieved. Light-trapping in PV cells increases the effective optical path-length in the semiconductor material leading to improved absorption and conversion efficiency. It has been shown that the effective optical path length can be increased by a factor of 4n2 using diffusive surfaces. Ultra-light-trapping can be achieved with optical filters that limit the escape angle of the diffused light. Holographic reflection gratings have been shown to act as angle-wavelength selective filters that can function as ultra-light-trapping filters. Results from an experimental reflection hologram are used to model the absorption enhancement factor for a silicon solar cell and light-trapping filter. The result shows a significant improvement in current generation for thin-film silicon solar cells under typical operating conditions.

An overview of crystalline silicon solar cell technology: Past, present, and future

NASA Astrophysics Data System (ADS)

Sopian, K.; Cheow, S. L.; Zaidi, S. H.

2017-09-01

Crystalline silicon (c-Si) solar cell, ever since its inception, has been identified as the only economically and environmentally sustainable renewable resource to replace fossil fuels. Performance c-Si based photovoltaic (PV) technology has been equal to the task. Its price has been reduced by a factor of 250 over last twenty years (from ˜ 76 USD to ˜ 0.3 USD); its market growth is expected to reach 100 GWP by 2020. Unfortunately, it is still 3-4 times higher than carbon-based fuels. With the matured PV manufacturing technology as it exists today, continuing price reduction poses stiff challenges. Alternate manufacturing approaches in combination with thin wafers, low (< 10 x) optical enhancement with Fresnel lenses, band-gap engineering for enhanced optical absorption, and newer, advanced solar cell configurations including partially transparent bifacial and back contact solar cells will be required. This paper will present a detailed, cost-based analysis of advanced solar cell manufacturing technologies aimed at higher (˜ 22 %) efficiency with existing equipment and processes.

Chimeric Lyssavirus Glycoproteins with Increased Immunological Potential

PubMed Central

Jallet, Corinne; Jacob, Yves; Bahloul, Chokri; Drings, Astrid; Desmezieres, Emmanuel; Tordo, Noël; Perrin, Pierre

1999-01-01

The rabies virus glycoprotein molecule (G) can be divided into two parts separated by a flexible hinge: the NH2 half (site II part) containing antigenic site II up to the linear region (amino acids [aa] 253 to 275 encompassing epitope VI [aa 264]) and the COOH half (site III part) containing antigenic site III and the transmembrane and cytoplasmic domains. The structural and immunological roles of each part were investigated by cell transfection and mouse DNA-based immunization with homogeneous and chimeric G genes formed by fusion of the site II part of one genotype (GT) with the site III part of the same or another GT. Various site II-site III combinations between G genes of PV (Pasteur virus strain) rabies (GT1), Mokola (GT3), and EBL1 (European bat lyssavirus 1 [GT5]) viruses were tested. Plasmids pGPV-PV, pGMok-Mok, pGMok-PV, and pGEBL1-PV induced transient expression of correctly transported and folded antigens in neuroblastoma cells and virus-neutralizing antibodies against parental viruses in mice, whereas, pG-PVIII (site III part only) and pGPV-Mok did not. The site III part of PV (GT1) was a strong inducer of T helper cells and was very effective at presenting the site II part of various GTs. Both parts are required for correct folding and transport of chimeric G proteins which have a strong potential value for immunological studies and development of multivalent vaccines. Chimeric plasmid pGEBL1-PV broadens the spectrum of protection against European lyssavirus genotypes (GT1, GT5, and GT6). PMID:9847325

On-Orbit Measurement of Next Generation Space Solar Cell Technology on the International Space Station

NASA Technical Reports Server (NTRS)

Wolford, David S.; Myers, Matthew G.; Prokop, Norman F.; Krasowski, Michael J.; Parker, David S.; Cassidy, Justin C.; Davies, William E.; Vorreiter, Janelle O.; Piszczor, Michael F.; McNatt, Jeremiah S.

2015-01-01

Measurement is essential for the evaluation of new photovoltaic (PV) technology for space solar cells. NASA Glenn Research Center (GRC) is in the process of measuring several solar cells in a supplemental experiment on NASA Goddard Space Flight Center's (GSFC) Robotic Refueling Mission's (RRM) Task Board 4 (TB4). Four industry and government partners have provided advanced PV devices for measurement and orbital environment testing. The experiment will be on-orbit for approximately 18 months. It is completely self-contained and will provide its own power and internal data storage. Several new cell technologies including four- junction (4J) Inverted Metamorphic Multijunction (IMM) cells will be evaluated and the results compared to ground-based measurements.

Capacity of wild-type and chemokine-armed parvovirus H-1PV for inhibiting neo-angiogenesis.

PubMed

Lavie, Muriel; Struyf, Sofie; Stroh-Dege, Alexandra; Rommelaere, Jean; Van Damme, Jo; Dinsart, Christiane

2013-12-01

Anti-angiogenic therapy has been recognized as a powerful potential strategy for impeding the growth of various tumors. However no major therapeutic effects have been observed to date, mainly because of the emergence of several resistance mechanisms. Among novel strategies to target tumor vasculature, some oncolytic viruses open up new prospects. In this context, we addressed the question whether the rodent parvovirus H-1PV can target endothelial cells. We show that cultures of human normal (HUVEC) and immortalized (KS-IMM) endothelial cells sustain an abortive viral cycle upon infection with H-1PV and are sensitive to H-1PV cytotoxicity. H-1PV significantly inhibits infected KS-IMM tumor growth. This effect may be traced back by the virus ability to both kill proliferating endothelial cells and inhibit VEGF production Recombinant H-1PV vectors can also transduce tumor cells with chemokines endowed with anti-angiogenesis properties, and warrant further validation for the treatment of highly vascularized tumors. © 2013 Elsevier Inc. All rights reserved.

Pressure-equalizing PV assembly and method

DOEpatents

Dinwoodie, Thomas L.

2004-10-26

Each PV assembly of an array of PV assemblies comprises a base, a PV module and a support assembly securing the PV module to a position overlying the upper surface of the base. Vents are formed through the base. A pressure equalization path extends from the outer surface of the PV module, past the PV module, to and through at least one of the vents, and to the lower surface of the base to help reduce wind uplift forces on the PV assembly. The PV assemblies may be interengaged, such as by interengaging the bases of adjacent PV assemblies. The base may include a main portion and a cover and the bases of adjacent PV assemblies may be interengaged by securing the covers of adjacent bases together.

Determining blood and plasma volumes using bioelectrical response spectroscopy

NASA Technical Reports Server (NTRS)

Siconolfi, S. F.; Nusynowitz, M. L.; Suire, S. S.; Moore, A. D. Jr; Leig, J.

1996-01-01

We hypothesized that an electric field (inductance) produced by charged blood components passing through the many branches of arteries and veins could assess total blood volume (TBV) or plasma volume (PV). Individual (N = 29) electrical circuits (inductors, two resistors, and a capacitor) were determined from bioelectrical response spectroscopy (BERS) using a Hewlett Packard 4284A Precision LCR Meter. Inductance, capacitance, and resistance from the circuits of 19 subjects modeled TBV (sum of PV and computed red cell volume) and PV (based on 125I-albumin). Each model (N = 10, cross validation group) had good validity based on 1) mean differences (-2.3 to 1.5%) between the methods that were not significant and less than the propagated errors (+/- 5.2% for TBV and PV), 2) high correlations (r > 0.92) with low SEE (< 7.7%) between dilution and BERS assessments, and 3) Bland-Altman pairwise comparisons that indicated "clinical equivalency" between the methods. Given the limitation of this study (10 validity subjects), we concluded that BERS models accurately assessed TBV and PV. Further evaluations of the models' validities are needed before they are used in clinical or research settings.

Distinct learning-induced changes in stimulus selectivity and interactions of GABAergic interneuron classes in visual cortex.

PubMed

Khan, Adil G; Poort, Jasper; Chadwick, Angus; Blot, Antonin; Sahani, Maneesh; Mrsic-Flogel, Thomas D; Hofer, Sonja B

2018-06-01

How learning enhances neural representations for behaviorally relevant stimuli via activity changes of cortical cell types remains unclear. We simultaneously imaged responses of pyramidal cells (PYR) along with parvalbumin (PV), somatostatin (SOM), and vasoactive intestinal peptide (VIP) inhibitory interneurons in primary visual cortex while mice learned to discriminate visual patterns. Learning increased selectivity for task-relevant stimuli of PYR, PV and SOM subsets but not VIP cells. Strikingly, PV neurons became as selective as PYR cells, and their functional interactions reorganized, leading to the emergence of stimulus-selective PYR-PV ensembles. Conversely, SOM activity became strongly decorrelated from the network, and PYR-SOM coupling before learning predicted selectivity increases in individual PYR cells. Thus, learning differentially shapes the activity and interactions of multiple cell classes: while SOM inhibition may gate selectivity changes, PV interneurons become recruited into stimulus-specific ensembles and provide more selective inhibition as the network becomes better at discriminating behaviorally relevant stimuli.

Pemphigus vulgaris of the cervix: diagnostic difficulties associated with the Pap test.

PubMed

Munhoz de Paula Alves Coelho, Karina; Stall, Jaqueline; Henrique Condeixa de França, Paulo; Cristina de Carvalho Tavares, Lara; Stefanello Bublitz, Giuliano; Loos, Beliza; Carvalho Costa, Luciana; Fronza Júnior, Hercílio

2015-08-01

Pemphigus vulgaris (PV) is a rare mucocutaneous disease caused by the abnormal production of antibodies against epithelial cell surface glycoproteins, resulting in loss of cell adhesion and intraepithelial blister formation. Cervical involvement in PV has been poorly reported, and there is little information regarding the criteria about consequential cytological changes identified in a Papanicolaou-stained cervicovaginal smear (Pap smear). Here, we report a case of PV manifesting in the cervix as well as the difficulty associated with the cytomorphological identification and interpretation of acantholytic cells. This case involved a 40-year-old patient with no history of Pap test abnormalities and no prior diagnosis of PV. In the cytological assessment, cells were identified both in isolation and in clusters that exhibited round nuclei of increased volume, inconspicuous nucleoli, and perinuclear halos. The patient underwent a cervical biopsy that revealed vesiculobullous lesions and morphological pattern consistent with PV. A skin biopsy confirmed this diagnosis. We concluded that knowledge of PV cytomorphology is important because difficulties associated with the identification and interpretation of acantholytic cells might be responsible for false positive diagnoses of cervical neoplasia. However, a suspected diagnosis of PV is possible if the cytological findings are carefully correlated with the clinical data. © 2015 Wiley Periodicals, Inc.

Generation of an Adenovirus-Parvovirus Chimera with Enhanced Oncolytic Potential

PubMed Central

El-Andaloussi, Nazim; Bonifati, Serena; Kaufmann, Johanna K.; Mailly, Laurent; Daeffler, Laurent; Deryckère, François; Nettelbeck, Dirk M.; Rommelaere, Jean

2012-01-01

In this study, our goal was to generate a chimeric adenovirus-parvovirus (Ad-PV) vector that combines the high-titer and efficient gene transfer of adenovirus with the anticancer potential of rodent parvovirus. To this end, the entire oncolytic PV genome was inserted into a replication-defective E1- and E3-deleted Ad5 vector genome. As we found that parvoviral NS expression inhibited Ad-PV chimera production, we engineered the parvoviral P4 early promoter, which governs NS expression, by inserting into its sequence tetracycline operator elements. As a result of these modifications, P4-driven expression was blocked in the packaging T-REx-293 cells, which constitutively express the tetracycline repressor, allowing high-yield chimera production. The chimera effectively delivered the PV genome into cancer cells, from which fully infectious replication-competent parvovirus particles were generated. Remarkably, the Ad-PV chimera exerted stronger cytotoxic activities against various cancer cell lines, compared with the PV and Ad parental viruses, while being still innocuous to a panel of tested healthy primary human cells. This Ad-PV chimera represents a novel versatile anticancer agent which can be subjected to further genetic manipulations in order to reinforce its enhanced oncolytic capacity through arming with transgenes or retargeting into tumor cells. PMID:22787235

Generation of an adenovirus-parvovirus chimera with enhanced oncolytic potential.

PubMed

El-Andaloussi, Nazim; Bonifati, Serena; Kaufmann, Johanna K; Mailly, Laurent; Daeffler, Laurent; Deryckère, François; Nettelbeck, Dirk M; Rommelaere, Jean; Marchini, Antonio

2012-10-01

In this study, our goal was to generate a chimeric adenovirus-parvovirus (Ad-PV) vector that combines the high-titer and efficient gene transfer of adenovirus with the anticancer potential of rodent parvovirus. To this end, the entire oncolytic PV genome was inserted into a replication-defective E1- and E3-deleted Ad5 vector genome. As we found that parvoviral NS expression inhibited Ad-PV chimera production, we engineered the parvoviral P4 early promoter, which governs NS expression, by inserting into its sequence tetracycline operator elements. As a result of these modifications, P4-driven expression was blocked in the packaging T-REx-293 cells, which constitutively express the tetracycline repressor, allowing high-yield chimera production. The chimera effectively delivered the PV genome into cancer cells, from which fully infectious replication-competent parvovirus particles were generated. Remarkably, the Ad-PV chimera exerted stronger cytotoxic activities against various cancer cell lines, compared with the PV and Ad parental viruses, while being still innocuous to a panel of tested healthy primary human cells. This Ad-PV chimera represents a novel versatile anticancer agent which can be subjected to further genetic manipulations in order to reinforce its enhanced oncolytic capacity through arming with transgenes or retargeting into tumor cells.

Numerical modeling of uncertainty and variability in the technology, manufacturing, and economics of crystalline silicon photovoltaics

NASA Astrophysics Data System (ADS)

Ristow, Alan H.

2008-10-01

Electricity generated from photovoltaics (PV) promises to satisfy the world's ever-growing thirst for energy without significant pollution and greenhouse gas emissions. At present, however, PV is several times too expensive to compete economically with conventional sources of electricity delivered via the power grid. To ensure long-term success, must achieve cost parity with electricity generated by conventional sources of electricity. This requires detailed understanding of the relationship between technology and economics as it pertains to PV devices and systems. The research tasks of this thesis focus on developing and using four types of models in concert to develop a complete picture of how solar cell technology and design choices affect the quantity and cost of energy produced by PV systems. It is shown in this thesis that high-efficiency solar cells can leverage balance-of-systems (BOS) costs to gain an economic advantage over solar cells with low efficiencies. This advantage is quantified and dubbed the "efficiency premium." Solar cell device models are linked to models of manufacturing cost and PV system performance to estimate both PV system cost and performance. These, in turn, are linked to a model of levelized electricity cost to estimate the per-kilowatt-hour cost of electricity produced by the PV system. A numerical PV module manufacturing cost model is developed to facilitate this analysis. The models and methods developed in this thesis are used to propose a roadmap to high-efficiency multicrystalline-silicon PV modules that achieve cost parity with electricity from the grid. The impact of PV system failures on the cost of electricity is also investigated; from this, a methodology is proposed for improving the reliability of PV inverters.

Increased Throughput and Sensitivity of Synchrotron-Based Characterization for Photovoltaic Materials

DOE PAGES

Morishige, Ashley E.; Laine, Hannu S.; Looney, Erin E.; ...

2017-04-03

Optimizing photovoltaic (PV) devices requires characterization and optimization across several length scales, from centimeters to nanometers. Synchrotron-based micro-X-ray fluorescence spectromicroscopy (μ-XRF) is a valuable link in the PV-related material and device characterization suite. μ-XRF maps of elemental distributions in PV materials have high spatial resolution and excellent sensitivity and can be measured on absorber materials and full devices. Recently, we implemented on-the-fly data collection (flyscan) at Beamline 2-ID-D at the Advanced Photon Source at Argonne National Laboratory, eliminating a 300 ms per-pixel overhead time. This faster scanning enables high-sensitivity (~10 14 atoms/cm 2), large-area (10 000s of μm 2), high-spatialmore » resolution (<;200 nm scale) maps to be completed within a practical scanning time. We specifically show that when characterizing detrimental trace metal precipitate distributions in multicrystalline silicon wafers for PV, flyscans can increase the productivity of μ-XRF by an order of magnitude. Additionally, flyscan μ-XRF mapping enables relatively large-area correlative microscopy. As an example, we map the transition metal distribution in a 50 μm-diameter laser-fired contact of a silicon solar cell before and after lasing. As a result, while we focus on μ-XRF of mc-Si wafers for PV, our results apply broadly to synchrotron-based mapping of PV absorbers and devices.« less

Synergistic actions of pemphigus vulgaris IgG, Fas-ligand and tumor necrosis factor-alpha during induction of basal cell shrinkage and acantholysis.

PubMed

Orlov, Maxim D; Chernyavsky, Alex I; Arredondo, Juan; Grando, Sergei A

2006-11-01

This study tested a recently proposed "Basal Cell Shrinkage" hypothesis of pemphigus acantholysis through a quantitative analysis of individual and cooperative effects of pemphigus vulgaris (PV) IgG, Fas-ligand (Fas-L) and tumor necrosis factor-alpha (TNFalpha) on keratinocyte (KC) volume (i.e. cell size) and adhesive properties. Exposure of KC monolayers and MatTek EpiDermFT tissues cultures to the physiologic concentrations of Fas-L, TNFalpha or IgGs from two PV patients resulted in various degrees of reversible changes, which were not observed in control cultures either exposed to normal IgG or left intact. Within 12-24 h of exposure, basal cells in experimental cultures lost their ability to form stress fibers, retracted cytoplasmic aprons and formed keratin aggregates, indicating that their cytoskeleton collapsed. The cell volume decreased significantly (p < 0.05) as the polygonal cell shape changed to a round one. The shrunk cells detached from their neighbors and the substrate, resulting in a reciprocal increase of both the areas of acantholysis and the number of detached KCs, respectively. Since in the skin of PV patients, KCs are targeted by autoantibodies concomitantly with being exposed to autocrine and paracrine pro-apoptotic and pro-inflammatory cytokines, we combined PV IgG with Fas-L and/or TNFalpha in the cell culture experiments. This amplified several fold an ability of PV IgG to cause basal cell shrinkage and detachment. The obtained results demonstrated for the first time that PV IgG works together with Fas-L and TNFalpha to induce acantholysis via basal cell shrinkage, which provides a novel mechanism explaining successful treatment of PV patients with TNFalpha inhibitors.

Transforming properties of Felis catus papillomavirus type 2 E6 and E7 putative oncogenes in vitro and their transcriptional activity in feline squamous cell carcinoma in vivo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Altamura, Gennaro, E-mail: gennaro.altamura@unina.it; Corteggio, Annunziata, E-mail: ancorteg@unina.it; Pacini, Laura, E-mail: PaciniL@students.iarc.fr

Felis catus papillomavirus type 2 (FcaPV2) DNA is found in feline cutaneous squamous cell carcinomas (SCCs); however, its biological properties are still uncharacterized. In this study, we successfully expressed FcaPV2 E6 and E7 putative oncogenes in feline epithelial cells and demonstrated that FcaPV2 E6 binds to p53, impairing its protein level. In addition, E6 and E7 inhibited ultraviolet B (UVB)-triggered accumulation of p53, p21 and pro-apoptotic markers such as Cleaved Caspase3, Bax and Bak, suggesting a synergistic action of the virus with UV exposure in tumour pathogenesis. Furthermore, FcaPV2 E7 bound to feline pRb and impaired pRb levels, resulting inmore » upregulation of the downstream pro-proliferative genes Cyclin A and Cdc2. Importantly, we demonstrated mRNA expression of FcaPV2 E2, E6 and E7 in feline SCC samples, strengthening the hypothesis of a causative role in the development of feline SCC. - Highlights: • FcaPV2 E6 binds to and deregulates feline p53 protein. • FcaPV2 E7 binds to and deregulates feline pRb protein. • FcaPV2 oncogenes inhibit UVB-induced apoptosis. • FcaPV2 E6E7 and E7 increase the lifespan of primary cells. • FcaPV2 E2, E6 and E7 are expressed at the mRNA level in feline SCC in vivo.« less

The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system

NASA Astrophysics Data System (ADS)

Bjørk, R.; Nielsen, K. K.

2015-10-01

The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system is examined using an analytical model for four different types of commercial PVs and a commercial bismuth telluride TEG. The TEG is applied directly on the back of the PV, so that the two devices have the same temperature. The PVs considered are crystalline Si (c-Si), amorphous Si (a-Si), copper indium gallium (di)selenide (CIGS) and cadmium telluride (CdTe) cells. The degradation of PV performance with temperature is shown to dominate the increase in power produced by the TEG, due to the low efficiency of the TEG. For c-Si, CIGS and CdTe PV cells the combined system produces a lower power and has a lower efficiency than the PV alone, whereas for an a-Si cell the total system performance may be slightly increased by the TEG.

Solar Photovoltaic Technology Basics | NREL

Science.gov Websites

For more information about solar photovoltaic energy, visit the following resources: Solar PV Photovoltaic Technology Basics Solar Photovoltaic Technology Basics Solar cells, also called photovoltaic (PV) cells by scientists, convert sunlight directly into electricity. PV gets its name from the

Superficial photoluminescence and PV conversion of nanoscale Si-layered systems at 400 nm

NASA Astrophysics Data System (ADS)

Kuznicki, Zbigniew T.; Meyrueis, Patrick; Sarrabayrouse, Gérard; Rousset, Bernard

2006-04-01

A surprising photovoltaic (PV) conversion at 400 nm has been observed in nanoscale Si-layered systems (ns-Si-ls) during spectral response measurements. In conventional solar cells the UV and blue PV conversion may be poor because of the surface recombination within a thin superficial layer. In multi-interface novel devices (MIND) containing ns-Si-ls this conversion is always negligible within an even thicker surface dead zone from which practically no free-carriers can be collected. So the measured 400 nm band PV conversion in MIND cells is totally inconsistent with usually observed effects. Another CE paradox concerns its inversely proportional variation versus incident flux intensity, lower the intensity higher the CE, which value can even exceed unity. This new effect is also localized at the superficial nanostratum and originates from postimplantation defects and nanostructures formed during the implantation process. A similar low energy free-carrier generation has been observed recently in MIND cells with buried ns-Si-ls having a relatively very thin superficial stratum because of an excellent electronic passivation. No available publication mentions such an effect despite extensive investigations on the subject of structural and optical properties of Si nanoparticles, Si nanolayers, new Si-based materials such as semiconductor silicides and the luminescence-center doped Si materials. In this work, the carrier collection properties of the superficial Si nanostratum are reported and discussed in detail in relation to incident flux intensity. An additional low energy generation was observed experimentally. The effect could have capital importance for a breakthrough in the PV conversion efficiency in Si solar cells with nanotransformations.

Does the visual system of the flying fox resemble that of primates? The distribution of calcium-binding proteins in the primary visual pathway of Pteropus poliocephalus.

PubMed

Ichida, J M; Rosa, M G; Casagrande, V A

2000-01-31

It has been proposed that flying foxes and echolocating bats evolved independently from early mammalian ancestors in such a way that flying foxes form one of the suborders most closely related to primates. A major piece of evidence offered in support of a flying fox-primate link is the highly developed visual system of flying foxes, which is theorized to be primate-like in several different ways. Because the calcium-binding proteins parvalbumin (PV) and calbindin (CB) show distinct and consistent distributions in the primate visual system, the distribution of these same proteins was examined in the flying fox (Pteropus poliocephalus) visual system. Standard immunocytochemical techniques reveal that PV labeling within the lateral geniculate nucleus (LGN) of the flying fox is sparse, with clearly labeled cells located only within layer 1, adjacent to the optic tract. CB labeling in the LGN is profuse, with cells labeled in all layers throughout the nucleus. Double labeling reveals that all PV+ cells also contain CB, and that these cells are among the largest in the LGN. In primary visual cortex (V1) PV and CB label different classes of non-pyramidal neurons. PV+ cells are found in all cortical layers, although labeled cells are found only rarely in layer I. CB+ cells are found primarily in layers II and III. The density of PV+ neuropil correlates with the density of cytochrome oxidase staining; however, no CO+ or PV+ or CB+ patches or blobs are found in V1. These results show that the distribution of calcium-binding proteins in the flying fox LGN is unlike that found in primates, in which antibodies for PV and CB label specific separate populations of relay cells that exist in different layers. Indeed, the pattern of calcium-binding protein distribution in the flying fox LGN is different from that reported in any other terrestrial mammal. Within V1 no PV+ patches, CO blobs, or patchy distribution of CB+ neuropil that might reveal interblobs characteristic of primate V1 are found; however, PV and CB are found in separate populations of non-pyramidal neurons. The types of V1 cells labeled with antibodies to PV and CB in all mammals examined including the flying fox suggest that the similarities in the cellular distribution of these proteins in cortex reflect the fact that this feature is common to all mammals.

Automatic Fault Recognition of Photovoltaic Modules Based on Statistical Analysis of Uav Thermography

NASA Astrophysics Data System (ADS)

Kim, D.; Youn, J.; Kim, C.

2017-08-01

As a malfunctioning PV (Photovoltaic) cell has a higher temperature than adjacent normal cells, we can detect it easily with a thermal infrared sensor. However, it will be a time-consuming way to inspect large-scale PV power plants by a hand-held thermal infrared sensor. This paper presents an algorithm for automatically detecting defective PV panels using images captured with a thermal imaging camera from an UAV (unmanned aerial vehicle). The proposed algorithm uses statistical analysis of thermal intensity (surface temperature) characteristics of each PV module to verify the mean intensity and standard deviation of each panel as parameters for fault diagnosis. One of the characteristics of thermal infrared imaging is that the larger the distance between sensor and target, the lower the measured temperature of the object. Consequently, a global detection rule using the mean intensity of all panels in the fault detection algorithm is not applicable. Therefore, a local detection rule based on the mean intensity and standard deviation range was developed to detect defective PV modules from individual array automatically. The performance of the proposed algorithm was tested on three sample images; this verified a detection accuracy of defective panels of 97 % or higher. In addition, as the proposed algorithm can adjust the range of threshold values for judging malfunction at the array level, the local detection rule is considered better suited for highly sensitive fault detection compared to a global detection rule.

Morphological characteristics of conjunctival squamous papillomas in relation to human papillomavirus infection.

PubMed

Mlakar, Jernej; Kocjan, Boštjan J; Hošnjak, Lea; Pižem, Jože; Beltram, Matej; Gale, Nina; Drnovšek-Olup, Brigita; Poljak, Mario

2015-03-01

To determine the prevalence of a broad spectrum of human papillomavirus (HPV) types in conjunctival papillomas and a possible difference in clinical and histopathological presentation of HPV-positive and HPV-negative papillomas. Formalin-fixed, paraffin-embedded papilloma tissue specimens obtained from 25 patients were analysed using six different PCR-based methods targeting 87 HPV types from four different papillomavirus (PV) genera: α-PV, β-PV, γ-PV and µ-PV, and in situ hybridisation for HPV-6/HPV-11. Slides were reviewed for pedunculated or sessile growth, the presence of goblet cells, keratinising or non-keratinising epithelium, elastosis, atypia and koilocytes. α-PV types HPV-6 and HPV-11 were detected in 19/25 (76%) conjunctival papilloma tissue specimens, 9 (47%) of which were also HPV-6/HPV-11 positive with in situ hybridisation. Six different β-PV types-HPV-9, HPV-12, HPV-20, HPV-21, HPV-22, HPV-24-were additionally detected in four cases, all of which were also HPV-6/HPV-11 positive. No γ-PVs or µ-PVs were found in any of the tested tissues samples. Extralimbal location (p=0.021), presence of goblet cells (p=0.005), non-keratinising squamous epithelium (p=0.005), and absence of elastosis (p=0.005) were associated with the presence of HPV-6/HPV-11. We demonstrated that certain clinical and histological features are more frequently associated with HPV infection and that HPV genera other than α-PV are most probably not significant factors in conjunctival papilloma occurrence. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Graphene-enhanced thermal interface materials for heat removal from photovoltaic solar cells

NASA Astrophysics Data System (ADS)

Saadah, M.; Gamalath, D.; Hernandez, E.; Balandin, A. A.

2016-09-01

The increase in the temperature of photovoltaic (PV) solar cells affects negatively their power conversion efficiency and decreases their lifetime. The negative effects are particularly pronounced in concentrator solar cells. Therefore, it is crucial to limit the PV cell temperature by effectively removing the excess heat. Conventional thermal phase change materials (PCMs) and thermal interface materials (TIMs) do not possess the thermal conductivity values sufficient for thermal management of the next generation of PV cells. In this paper, we report the results of investigation of the increased efficiency of PV cells with the use of graphene-enhanced TIMs. Graphene reveals the highest values of the intrinsic thermal conductivity. It was also shown that the thermal conductivity of composites can be increased via utilization of graphene fillers. We prepared TIMs with up to 6% of graphene designed specifically for PV cell application. The solar cells were tested using the solar simulation module. It was found that the drop in the output voltage of the solar panel under two-sun concentrated illumination can be reduced from 19% to 6% when grapheneenhanced TIMs are used. The proposed method can recover up to 75% of the power loss in solar cells.

Electricity from photovoltaic solar cells. Flat-Plate Solar Array Project of the US Department of Energy's National Photovoltaics Program: 10 years of progress

NASA Technical Reports Server (NTRS)

Christensen, Elmer

1985-01-01

The objectives were to develop the flat-plate photovoltaic (PV) array technologies required for large-scale terrestrial use late in the 1980s and in the 1990s; advance crystalline silicon PV technologies; develop the technologies required to convert thin-film PV research results into viable module and array technology; and to stimulate transfer of knowledge of advanced PV materials, solar cells, modules, and arrays to the PV community. Progress reached on attaining these goals, along with future recommendations are discussed.

Immune Status, Strain Background, and Anatomic Site of Inoculation Affect Mouse Papillomavirus (MmuPV1) Induction of Exophytic Papillomas or Endophytic Trichoblastomas

PubMed Central

Sundberg, John P.; Proctor, Mary; Ingle, Arvind; Silva, Kathleen A.; Dadras, Soheil S.; Jenson, A. Bennett; Ghim, Shin-je

2014-01-01

Papillomaviruses (PVs) induce papillomas, premalignant lesions, and carcinomas in a wide variety of species. PVs are classified first based on their host and tissue tropism and then their genomic diversities. A laboratory mouse papillomavirus, MmuPV1 (formerly MusPV), was horizontally transmitted within an inbred colony of NMRI-Foxn1nu/Foxn1nu (nude; T cell deficient) mice of an unknown period of time. A ground-up, filtered papilloma inoculum was not capable of infecting C57BL/6J wild-type mice; however, immunocompetent, alopecic, S/RV/Cri-ba/ba (bare) mice developed small papillomas at injection sites that regressed. NMRI-Foxn1nu and B6.Cg-Foxn1nu, but not NU/J-Foxn1nu, mice were susceptible to MmuPV1 infection. B6 congenic strains, but not other congenic strains carrying the same allelic mutations, lacking B- and T-cells, but not B-cells alone, were susceptible to infection, indicating that mouse strain and T-cell deficiency are critical to tumor formation. Lesions initially observed were exophytic papillomas around the muzzle, exophytic papillomas on the tail, and condylomas of the vaginal lining which could be induced by separate scarification or simultaneous scarification of MmuPV1 at all four sites. On the dorsal skin, locally invasive, poorly differentiated tumors developed with features similar to human trichoblastomas. Transcriptome analysis revealed significant differences between the normal skin in these anatomic sites and in papillomas versus trichoblastomas. The primarily dysregulated genes involved molecular pathways associated with cancer, cellular development, cellular growth and proliferation, cell morphology, and connective tissue development and function. Although trichoepitheliomas are benign, aggressive tumors, few of the genes commonly associated with basal cell carcinoma or squamous cells carcinoma were highly dysregulated. PMID:25474466

Pressure equalizing photovoltaic assembly and method

DOEpatents

Dinwoodie, Thomas L [Piedmont, CA

2003-05-27

Each PV assembly of an array of PV assemblies comprises a base, a PV module and a support assembly securing the PV module to a position overlying the upper surface of the base. Vents are formed through the base. A pressure equalization path extends from the outer surface of the PV module, past the peripheral edge of the PV module, to and through at least one of the vents, and to the lower surface of the base to help reduce wind uplift forces on the PV assembly. The PV assemblies may be interengaged, such as by interengaging the bases of adjacent PV assemblies. The base may include a main portion and a cover and the bases of adjacent PV assemblies may be interengaged by securing the covers of adjacent bases together.

S4(13)-PV cell-penetrating peptide induces physical and morphological changes in membrane-mimetic lipid systems and cell membranes: implications for cell internalization.

PubMed

Cardoso, Ana M S; Trabulo, Sara; Cardoso, Ana L; Lorents, Annely; Morais, Catarina M; Gomes, Paula; Nunes, Cláudia; Lúcio, Marlene; Reis, Salette; Padari, Kärt; Pooga, Margus; Pedroso de Lima, Maria C; Jurado, Amália S

2012-03-01

The present work aims to gain insights into the role of peptide-lipid interactions in the mechanisms of cellular internalization and endosomal escape of the S4(13)-PV cell-penetrating peptide, which has been successfully used in our laboratory as a nucleic acid delivery system. A S4(13)-PV analogue, S4(13)-PVscr, displaying a scrambled amino acid sequence, deficient cell internalization and drug delivery inability, was used in this study for comparative purposes. Differential scanning calorimetry, fluorescence polarization and X-ray diffraction at small and wide angles techniques showed that both peptides interacted with anionic membranes composed of phosphatidylglycerol or a mixture of this lipid with phosphatidylethanolamine, increasing the lipid order, shifting the phase transition to higher temperatures and raising the correlation length between the bilayers. However, S4(13)-PVscr, in contrast to the wild-type peptide, did not promote lipid domain segregation and induced the formation of an inverted hexagonal lipid phase instead of a cubic phase in the lipid systems assayed. Electron microscopy showed that, as opposed to S4(13)-PVscr, the wild-type peptide induced the formation of a non-lamellar organization in membranes of HeLa cells. We concluded that lateral phase separation and destabilization of membrane lamellar structure without compromising membrane integrity are on the basis of the lipid-driven and receptor-independent mechanism of cell entry of S4(13)-PV peptide. Overall, our results can contribute to a better understanding of the role of peptide-lipid interactions in the mechanisms of cell-penetrating peptide membrane translocation, helping in the future design of more efficient cell-penetrating peptide-based drug delivery systems. Copyright © 2011 Elsevier B.V. All rights reserved.

Performance analysis of high-concentrated multi-junction solar cells in hot climate

NASA Astrophysics Data System (ADS)

Ghoneim, Adel A.; Kandil, Kandil M.; Alzanki, Talal H.; Alenezi, Mohammad R.

2018-03-01

Multi-junction concentrator solar cells are a promising technology as they can fulfill the increasing energy demand with renewable sources. Focusing sunlight upon the aperture of multi-junction photovoltaic (PV) cells can generate much greater power densities than conventional PV cells. So, concentrated PV multi-junction solar cells offer a promising way towards achieving minimum cost per kilowatt-hour. However, these cells have many aspects that must be fixed to be feasible for large-scale energy generation. In this work, a model is developed to analyze the impact of various atmospheric factors on concentrator PV performance. A single-diode equivalent circuit model is developed to examine multi-junction cells performance in hot weather conditions, considering the impacts of both temperature and concentration ratio. The impacts of spectral variations of irradiance on annual performance of various high-concentrated photovoltaic (HCPV) panels are examined, adapting spectra simulations using the SMARTS model. Also, the diode shunt resistance neglected in the existing models is considered in the present model. The present results are efficiently validated against measurements from published data to within 2% accuracy. Present predictions show that the single-diode model considering the shunt resistance gives accurate and reliable results. Also, aerosol optical depth (AOD) and air mass are most important atmospheric parameters having a significant impact on HCPV cell performance. In addition, the electrical efficiency (η) is noticed to increase with concentration to a certain concentration degree after which it decreases. Finally, based on the model predictions, let us conclude that the present model could be adapted properly to examine HCPV cells' performance over a broad range of operating conditions.

Dual Stem Loops within the Poliovirus Internal Ribosomal Entry Site Control Neurovirulence

PubMed Central

Gromeier, Matthias; Bossert, Birgit; Arita, Mineo; Nomoto, Akio; Wimmer, Eckard

1999-01-01

In the human central nervous system, susceptibility to poliovirus (PV) infection is largely confined to a specific subpopulation of neuronal cells. PV tropism is likely to be determined by cell-external components such as the PV receptor CD155, as well as cell-internal constraints such as the availability of a suitable microenvironment for virus propagation. We reported previously that the exchange of the cognate internal ribosomal entry site (IRES) within the 5′ nontranslated region of PV with its counterpart from human rhinovirus type 2 (HRV2) can eliminate the neuropathogenic phenotype in a transgenic mouse model for poliomyelitis without diminishing the growth properties in HeLa cells. We now show that attenuation of neurovirulence of PV/HRV2 chimeras is not confined to CD155 transgenic mice but is evident also after intraspinal inoculation into Cynomolgus monkeys. We have dissected the PV and HRV2 IRES elements to determine those structures responsible for neurovirulence (or attenuation) of these chimeric viruses. We report that two adjacent stem loop structures within the IRES cooperatively determine neuropathogenicity. PMID:9882296

Cellular Inhibition of Checkpoint Kinase 2 (Chk2) and Potentiation of Camptothecins and Radiation by the Novel Chk2 Inhibitor PV1019 [7-Nitro-1H-indole-2-carboxylic acid {4-[1-(guanidinohydrazone)-ethyl]-phenyl}-amide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jobson, Andrew G.; Lountos, George T.; Lorenzi, Philip L.

2010-04-05

Chk2 is a checkpoint kinase involved in the ataxia telangiectasia mutated pathway, which is activated by genomic instability and DNA damage, leading to either cell death (apoptosis) or cell cycle arrest. Chk2 provides an unexplored therapeutic target against cancer cells. We recently reported 4,4'-diacetyldiphenylurea-bis(guanylhydrazone) (NSC 109555) as a novel chemotype Chk2 inhibitor. We have now synthesized a derivative of NSC 109555, PV1019 (NSC 744039) [7-nitro-1H-indole-2-carboxylic acid {l_brace}4-[1-(guanidinohydrazone)-ethyl]-phenyl{r_brace}-amide], which is a selective submicromolar inhibitor of Chk2 in vitro. The cocrystal structure of PV1019 bound in the ATP binding pocket of Chk2 confirmed enzymatic/biochemical observations that PV1019 acts as a competitive inhibitormore » of Chk2 with respect to ATP. PV1019 was found to inhibit Chk2 in cells. It inhibits Chk2 autophosphorylation (which represents the cellular kinase activation of Chk2), Cdc25C phosphorylation, and HDMX degradation in response to DNA damage. PV1019 also protects normal mouse thymocytes against ionizing radiation-induced apoptosis, and it shows synergistic antiproliferative activity with topotecan, camptothecin, and radiation in human tumor cell lines. We also show that PV1019 and Chk2 small interfering RNAs can exert antiproliferative activity themselves in the cancer cells with high Chk2 expression in the NCI-60 screen. These data indicate that PV1019 is a potent and selective inhibitor of Chk2 with chemotherapeutic and radiosensitization potential.« less

Persistent poliovirus infection of human fetal brain cells.

PubMed

Pavio, N; Buc-Caron, M H; Colbère-Garapin, F

1996-09-01

It has been suggested that poliovirus (PV), the causative agent of poliomyelitis, could persist in surviving patients. We have previously shown that PV can persistently infect some human cell lines in vitro, particularly neuroblastoma cell lines. We report here an ex vivo model in which PV can persistently infect primary cultures of human fetal brain cells. Two mutations involving capsid residues 142 of VP2 and 95 of VP1 were repeatedly selected during the persistent infections. These residues are located in capsid regions known to be involved in interactions between PV and its receptor. During the first week after infection, viral antigens were found in cells of both the neuronal and glial lineages. In contrast, 2 weeks after infection, viral antigens were detected almost exclusively in cells of the neuronal lineage. They were detected predominantly in cells expressing a marker of early commitment to the neuronal lineage, MAP-5, particularly in neuroblasts. Viral antigens were also found in immature progenitors expressing a neuroepithelium marker, nestin, and in cells expressing a marker of postmitotic neurons, MAP-2. The presence of viral antigens in postmitotic neurons suggests that PV can persist in neurons of patients who have survived poliomyelitis.

Design and Analysis of Photovoltaic (PV) Power Plant at Different Locations in Malaysia

NASA Astrophysics Data System (ADS)

Islam, M. A.; Hasanuzzaman, M.; Rahim, N. A.

2018-05-01

Power generation from sun oriented vitality through a photovoltaic (PV) system is ended up prevalent over the world due to clean innovation. Geographical location of Malaysia is very favorable for PV power generation system. The Malaysian government has also taken different steps to increase the use of solar energy especially by emphasizing on building integrated PV (BIPV) system. Comparative study on the feasibility of BIPV installation at the different location of Malaysia is rarely found. On the other hand, solar cell temperature has a negative impact on the electricity generation. So in this study cost effectiveness and initial investment cost of building integrated grid connected solar PV power plant in different regions of Malaysia have been carried. The effect of PV solar cell temperature on the payback period (PBP) is also investigated. Highest PBP is 12.38 years at Selangor and lowest PBP is 9.70 years at Sabah (Kota Kinabalu). Solar cell temperature significantly increases the PBP of PV plant and highest 14.64% and lowest 13.20% raise of PBP are encountered at Penang and Sarawak respectively.

Six Sigma-based approach to optimise the diffusion process of crystalline silicon solar cell manufacturing

NASA Astrophysics Data System (ADS)

Prasad, A. Guru; Saravanan, S.; Gijo, E. V.; Dasari, Sreenivasa Murty; Tatachar, Raghu; Suratkar, Prakash

2016-02-01

Silicon-based photovoltaics (PV) plays the dominant role in the history of PV due to the continuous process and technology improvement in silicon solar cells and its manufacturing flow. In general, silicon solar cell process uses either p-type- or n-type-doped silicon as the starting material. Currently, most of the PV industries use p-type, boron-doped silicon wafer as the starting material. In this work too, the boron-doped wafers were considered as the starting material to create pn junction and phosphorus was used as n-type doping material. Industries use either phosphorous oxy chloride (POCl3) or ortho phosphoric acid (H3PO4) as the precursor for doping phosphorous. While the industries use POCl3 as the precursor, the throughput is lesser than that of the industries' use of H3PO4 due to the manufacturing limitations of the POCl3-based equipments. Hence, in order to achieve the operational excellence in POCl3-based equipments, business strategies such as the Six Sigma methodology have to be adapted. This paper describes the application of Six Sigma Define-Measure-Analyze-Improve-Control methodology for throughput improvement of the phosphorus doping process. The optimised recipe has been implemented in the production and it is running successfully. As a result of this project, an effective gain of 0.9 MW was reported per annum.

Influence of different TiO2 blocking films on the photovoltaic performance of perovskite solar cells

NASA Astrophysics Data System (ADS)

Zhang, Chenxi; Luo, Yudan; Chen, Xiaohong; Ou-Yang, Wei; Chen, Yiwei; Sun, Zhuo; Huang, Sumei

2016-12-01

Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic (PV) cells. Cell structures based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive and brisk advances, holding great potential to grow into a mature PV technology. High power conversion efficiency (PCE) values have been obtained from the mesoscopic configuration in which a few hundred nano-meter thick mesoporous scaffold (e.g. TiO2 or Al2O3) infiltrated by perovskite absorber was sandwiched between the electron and hole transport layers. A uniform and compact hole-blocking layer is necessary for high efficient perovskite-based thin film solar cells. In this study, we investigated the characteristics of TiO2 compact layer using various methods and its effects on the PV performance of perovskite solar cells. TiO2 compact layer was prepared by a sol-gel method based on titanium isopropoxide and HCl, spin-coating of titanium diisopropoxide bis (acetylacetonate), screen-printing of Dyesol's bocking layer titania paste, and a chemical bath deposition (CBD) technique via hydrolysis of TiCl4, respectively. The morphological and micro-structural properties of the formed compact TiO2 layers were characterized by scanning electronic microscopy and X-ray diffraction. The analyses of devices performance characteristics showed that surface morphologies of TiO2 compact films played a critical role in affecting the efficiencies. The nanocrystalline TiO2 film deposited via the CBD route acts as the most efficient hole-blocking layer and achieves the best performance in perovskite solar cells. The CBD-based TiO2 compact and dense layer offers a small series resistance and a large recombination resistance inside the device, and makes it possible to achieve a high power conversion efficiency of 12.80%.

How I treat polycythemia vera.

PubMed

Passamonti, Francesco

2012-07-12

Polycythemia vera (PV) is a clonal disorder characterized by unwarranted production of red blood cells. In the majority of cases, PV is driven by oncogenic mutations that constitutively activate the JAK-STAT signal transduction pathway, such as JAK2 V617F, or exon 12 mutations or LNK mutations. Diagnosis of PV is based on the WHO criteria. Diagnosis of post-PV myelofibrosis is established according to the International Working Group for Myeloproliferative Neoplasms Research and Treatment criteria. Different clinical presentations of PV are discussed. Prognostication of PV is tailored to the most frequent complication during follow-up, namely, thrombosis. Age older than 60 years and prior history of thrombosis are the 2 main risk factors for disease stratification. Correlations are emerging between leukocytosis, JAK2(V617F) mutation, BM fibrosis, and different outcomes of PV, which need to be confirmed in prospective studies. In my practice, hydroxyurea is still the "gold standard" when cytoreduction is needed, even though pegylated IFN-alfa-2a and ruxolitinib might be useful in particular settings. Results of phase 1 or 2 studies concerning these latter agents should however be confirmed by the ongoing randomized phase 3 clinical trials. In this paper, I discuss the main problems encountered in daily clinical practice with PV patients regarding diagnosis, prognostication, and therapy.

Complementary induction of immunogenic cell death by oncolytic parvovirus H-1PV and gemcitabine in pancreatic cancer.

PubMed

Angelova, Assia L; Grekova, Svitlana P; Heller, Anette; Kuhlmann, Olga; Soyka, Esther; Giese, Thomas; Aprahamian, Marc; Bour, Gaétan; Rüffer, Sven; Cziepluch, Celina; Daeffler, Laurent; Rommelaere, Jean; Werner, Jens; Raykov, Zahari; Giese, Nathalia A

2014-05-01

Novel therapies employing oncolytic viruses have emerged as promising anticancer modalities. The cure of particularly aggressive malignancies requires induction of immunogenic cell death (ICD), coupling oncolysis with immune responses via calreticulin, ATP, and high-mobility group box protein B1 (HMGB1) release from dying tumor cells. The present study shows that in human pancreatic cancer cells (pancreatic ductal adenocarcinoma [PDAC] cells n=4), oncolytic parvovirus H-1 (H-1PV) activated multiple interconnected death pathways but failed to induce calreticulin exposure or ATP release. In contrast, H-1PV elevated extracellular HMGB1 levels by 4.0±0.5 times (58%±9% of total content; up to 100 ng/ml) in all infected cultures, whether nondying, necrotic, or apoptotic. An alternative secretory route allowed H-1PV to overcome the failure of gemcitabine to trigger HMGB1 release, without impeding cytotoxicity or other ICD activities of the standard PDAC medication. Such broad resistance of H-1PV-induced HMGB1 release to apoptotic blockage coincided with but was uncoupled from an autocrine interleukin-1β (IL-1β) loop. That and the pattern of viral determinants maintained in gemcitabine-treated cells suggested the activation of an inflammasome/caspase 1 (CASP1) platform alongside DNA detachment and/or nuclear exclusion of HMGB1 during early stages of the viral life cycle. We concluded that H-1PV infection of PDAC cells is signaled through secretion of the alarmin HMGB1 and, besides its own oncolytic effect, might convert drug-induced apoptosis into an ICD process. A transient arrest of cells in the cyclin A1-rich S phase would suffice to support compatibility of proliferation-dependent H-1PV with cytotoxic regimens. These properties warrant incorporation of the oncolytic virus H-1PV, which is not pathogenic in humans, into multimodal anticancer treatments. The current therapeutic concepts targeting aggressive malignancies require an induction of immunogenic cell death characterized by exposure of calreticulin (CRT) as well as release of ATP and HMGB1 from dying cells. In pancreatic tumor cells (PDAC cells) infected with the oncolytic parvovirus H-1PV, only HMGB1 was released by all infected cells, whether nondying, necrotic, or succumbing to one of the programmed death pathways, including contraproductive apoptosis. Our data suggest that active secretion of HMGB1 from PDAC cells is a sentinel reaction emerging during early stages of the viral life cycle, irrespective of cell death, that is compatible with and complements cytotoxic regimens. Consistent induction of HMGB1 secretion raised the possibility that this reaction might be a general "alarming" phenomenon characteristic of H-1PV's interaction with the host cell; release of IL-1β points to the possible involvement of a danger-sensing inflammasome platform. Both provide a basis for further virus-oriented studies.

Complementary Induction of Immunogenic Cell Death by Oncolytic Parvovirus H-1PV and Gemcitabine in Pancreatic Cancer

PubMed Central

Angelova, Assia L.; Grekova, Svitlana P.; Heller, Anette; Kuhlmann, Olga; Soyka, Esther; Giese, Thomas; Aprahamian, Marc; Bour, Gaétan; Rüffer, Sven; Cziepluch, Celina; Daeffler, Laurent; Rommelaere, Jean; Werner, Jens; Raykov, Zahari

2014-01-01

ABSTRACT Novel therapies employing oncolytic viruses have emerged as promising anticancer modalities. The cure of particularly aggressive malignancies requires induction of immunogenic cell death (ICD), coupling oncolysis with immune responses via calreticulin, ATP, and high-mobility group box protein B1 (HMGB1) release from dying tumor cells. The present study shows that in human pancreatic cancer cells (pancreatic ductal adenocarcinoma [PDAC] cells; n = 4), oncolytic parvovirus H-1 (H-1PV) activated multiple interconnected death pathways but failed to induce calreticulin exposure or ATP release. In contrast, H-1PV elevated extracellular HMGB1 levels by 4.0 ± 0.5 times (58% ± 9% of total content; up to 100 ng/ml) in all infected cultures, whether nondying, necrotic, or apoptotic. An alternative secretory route allowed H-1PV to overcome the failure of gemcitabine to trigger HMGB1 release, without impeding cytotoxicity or other ICD activities of the standard PDAC medication. Such broad resistance of H-1PV-induced HMGB1 release to apoptotic blockage coincided with but was uncoupled from an autocrine interleukin-1β (IL-1β) loop. That and the pattern of viral determinants maintained in gemcitabine-treated cells suggested the activation of an inflammasome/caspase 1 (CASP1) platform alongside DNA detachment and/or nuclear exclusion of HMGB1 during early stages of the viral life cycle. We concluded that H-1PV infection of PDAC cells is signaled through secretion of the alarmin HMGB1 and, besides its own oncolytic effect, might convert drug-induced apoptosis into an ICD process. A transient arrest of cells in the cyclin A1-rich S phase would suffice to support compatibility of proliferation-dependent H-1PV with cytotoxic regimens. These properties warrant incorporation of the oncolytic virus H-1PV, which is not pathogenic in humans, into multimodal anticancer treatments. IMPORTANCE The current therapeutic concepts targeting aggressive malignancies require an induction of immunogenic cell death characterized by exposure of calreticulin (CRT) as well as release of ATP and HMGB1 from dying cells. In pancreatic tumor cells (PDAC cells) infected with the oncolytic parvovirus H-1PV, only HMGB1 was released by all infected cells, whether nondying, necrotic, or succumbing to one of the programmed death pathways, including contraproductive apoptosis. Our data suggest that active secretion of HMGB1 from PDAC cells is a sentinel reaction emerging during early stages of the viral life cycle, irrespective of cell death, that is compatible with and complements cytotoxic regimens. Consistent induction of HMGB1 secretion raised the possibility that this reaction might be a general “alarming” phenomenon characteristic of H-1PV's interaction with the host cell; release of IL-1β points to the possible involvement of a danger-sensing inflammasome platform. Both provide a basis for further virus-oriented studies. PMID:24574398

Investigation of the photovoltaic cell/ thermoelectric element hybrid system performance

NASA Astrophysics Data System (ADS)

Cotfas, D. T.; Cotfas, P. A.; Machidon, O. M.; Ciobanu, D.

2016-06-01

The PV/TEG hybrid system, consisting of the photovoltaic cells and thermoelectric element, is presented in the paper. The dependence of the PV/TEG hybrid system parameters on the illumination levels and the temperature is analysed. The maxim power values of the photovoltaic cell, of the thermoelectric element and of the PV/TEG system are calculated and a comparison between them is presented and analysed. An economic analysis is also presented.

Traceable calibration of photovoltaic reference cells using natural sunlight

NASA Astrophysics Data System (ADS)

Müllejans, H.; Zaaiman, W.; Pavanello, D.; Dunlop, E. D.

2018-02-01

At the European Solar Test Installation (ESTI) photovoltaic (PV) reference cells are calibrated traceably to SI units via the World Radiometric Reference (WRR) using natural sunlight. The Direct Sunlight Method (DSM) is described in detail and the latest measurement results and an updated uncertainty budget are reported. These PV reference cells then provide a practical means for measuring the irradiance of natural or simulated sunlight during the calibration of other PV devices.

Materials That Enhance Efficiency and Radiation Resistance of Solar Cells

NASA Technical Reports Server (NTRS)

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%.

Solar concentrator modules with silicone-on-glass Fresnel lens panels and multijunction cells.

PubMed

Rumyantsev, Valery D

2010-04-26

High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute. The approach to R&D of the solar PV modules is based on the concepts of sunlight concentration by small-aperture area Fresnel lenses and "all-glass" module design. The small-aperture area lenses are arranged as a panel with silicone-on-glass structure where the glass plate serves as the front surface of a module. In turn, high-efficiency InGaP/(In)GaAs/Ge cells are arranged on a rear module panel mounted on a glass plate which functions as a heat sink and integrated protective cover for the cells. The developed PV modules and sun trackers are characterized by simple design, and are regarded as the prototypes for further commercialization.

Notch1 Signaling Regulates the Th17/Treg Immune Imbalance in Patients with Psoriasis Vulgaris.

PubMed

Ma, Lei; Xue, HaiBo; Gao, Tianqin; Gao, MeiLan; Zhang, YuJie

2018-01-01

To evaluate the regulating effect of Notch1 signaling on Th17/Treg immune imbalance in psoriasis vulgaris (PV). Notch1, Hes-1, ROR γ t, Foxp3, IL-17, and IL-10 mRNA expression, as well as Th17 and Treg cell percentages in peripheral CD4 + T cells, were detected by real-time quantitative RT-PCR and flow cytometry, and serum concentrations of IL-17 and IL-10 were detected by ELISA in 36 PV patients and 32 healthy controls. Additionally, CD4 + T cells from 12 PV patients were treated with γ -secretase inhibitor DAPT, and the above indexes were measured. PV patients presented distinct Th17/Treg immune imbalance and highly expressed Notch1 and Hes-1 mRNA levels, which were positively correlated with psoriasis area and severity index (PASI) and the ratios of Th17/Treg and ROR γ t/Foxp3. DAPT treatment resulted in the obvious downregulation of Th17 cell percentage in cocultured CD4 + T cells, ROR γ t and IL-17 mRNA levels, and IL-17 concentration in cell-free supernatant from cocultured CD4 + T cells of PV patients in a dose-dependent manner, while there was no significant influence on Treg cell percentage, Foxp3, and IL-10 expression, therefore leading to the recovery of Th17/Treg immune imbalance. Notch1 signaling may contribute to the pathogenesis of PV by regulating Th17/Treg immune imbalance.

Distributed solar radiation fast dynamic measurement for PV cells

NASA Astrophysics Data System (ADS)

Wan, Xuefen; Yang, Yi; Cui, Jian; Du, Xingjing; Zheng, Tao; Sardar, Muhammad Sohail

2017-10-01

To study the operating characteristics about PV cells, attention must be given to the dynamic behavior of the solar radiation. The dynamic behaviors of annual, monthly, daily and hourly averages of solar radiation have been studied in detail. But faster dynamic behaviors of solar radiation need more researches. The solar radiation random fluctuations in minute-long or second-long range, which lead to alternating radiation and cool down/warm up PV cell frequently, decrease conversion efficiency. Fast dynamic processes of solar radiation are mainly relevant to stochastic moving of clouds. Even in clear sky condition, the solar irradiations show a certain degree of fast variation. To evaluate operating characteristics of PV cells under fast dynamic irradiation, a solar radiation measuring array (SRMA) based on large active area photodiode, LoRa spread spectrum communication and nanoWatt MCU is proposed. This cross photodiodes structure tracks fast stochastic moving of clouds. To compensate response time of pyranometer and reduce system cost, the terminal nodes with low-cost fast-responded large active area photodiode are placed besides positions of tested PV cells. A central node, consists with pyranometer, large active area photodiode, wind detector and host computer, is placed in the center of the central topologies coordinate to scale temporal envelope of solar irradiation and get calibration information between pyranometer and large active area photodiodes. In our SRMA system, the terminal nodes are designed based on Microchip's nanoWatt XLP PIC16F1947. FDS-100 is adopted for large active area photodiode in terminal nodes and host computer. The output current and voltage of each PV cell are monitored by I/V measurement. AS62-T27/SX1278 LoRa communication modules are used for communicating between terminal nodes and host computer. Because the LoRa LPWAN (Low Power Wide Area Network) specification provides seamless interoperability among Smart Things without the need of complex local installations, configuring of our SRMA system is very easy. Lora also provides SRMA a means to overcome the short communication distance and weather signal propagation decline such as in ZigBee and WiFi. The host computer in SRMA system uses the low power single-board PC EMB-3870 which was produced by NORCO. Wind direction sensor SM5386B and wind-force sensor SM5387B are installed to host computer through RS-485 bus for wind reference data collection. And Davis 6450 solar radiation sensor, which is a precision instrument that detects radiation at wavelengths of 300 to 1100 nanometers, allow host computer to follow real-time solar radiation. A LoRa polling scheme is adopt for the communication between host computer and terminal nodes in SRMA. An experimental SRMA has been established. This system was tested in Ganyu, Jiangshu province from May to August, 2016. In the test, the distances between the nodes and the host computer were between 100m and 1900m. At work, SRMA system showed higher reliability. Terminal nodes could follow the instructions from host computer and collect solar radiation data of distributed PV cells effectively. And the host computer managed the SRAM and achieves reference parameters well. Communications between the host computer and terminal nodes were almost unaffected by the weather. In conclusion, the testing results show that SRMA could be a capable method for fast dynamic measuring about solar radiation and related PV cell operating characteristics.

Numerical modelling of phase-change material used for PV panels cooling

NASA Astrophysics Data System (ADS)

Sellami, Assia; Elotmani, Rabie; Kandoussi, Khalid; Eljouad, Mohamed; Hajjaji, Abdelowahed; Boutaous, M'Hamed

2017-12-01

Passive cooling of a PV solar panel using phase-change material (PCM) may play an important role in increasing efficiency of PV cells. Because it does not need a maintenance and does not release greenhouses gases, PCM seems to be a good way to decrease the among of overheating of PV cell. The aims of this paper describes a detailed multiphysical issue in order to understand the effect of PCM (RT25) in keeping PV cell temperature close to ambient. The study is focused on modeling the heat and mass transfer in a PCM domain by modifying the buoyancy term in momentum equation. Due to a phase-change and free convection, transient incompressible flow is taken into account to explain the dynamic variations of the velocity profile and viscosity distribution. With standard condition of irradiation and heat flux on both sides of the PV panel, a melt front has been tracked by the energy equation, which gives a good argument for the temperature evolution during phase-change.

Novel laboratory mouse papillomavirus (MusPV) infection.

PubMed

Ingle, A; Ghim, S; Joh, J; Chepkoech, I; Bennett Jenson, A; Sundberg, J P

2011-03-01

Most papillomaviruses (PVs) are oncogenic. There are at least 100 different human PVs and 65 nonhuman vertebrate hosts, including wild rodents, which have species-specific PV infections. Florid papillomatosis arose in a colony of NMRI-Foxn1(nu)/Foxn1(nu) (nude) mice at the Advanced Centre for Treatment Research and Education in Cancer in India. Lesions appeared at the mucocutaneous junctions of the nose and mouth. Histologically, lesions were classical papillomas with epidermal hyperplasia on thin fibrovascular stalks in a verrucous pattern. Koilocytotic cells were observed in the stratum granulosum of the papillomatous lesions. Immunohistochemically, these abnormal cells were positive for PV group-specific antigens. With transmission electron microscopy, virus particles were observed in crystalline intranuclear inclusions within keratinocytes. The presence of a mouse PV, designated MusPV, was confirmed by amplification of PV DNA with degenerative primers specific for PVs. This report is the first of a PV and its related disease in laboratory mice.

The effect of bovine lactoferrin and lactoferricin B on the ability of feline calicivirus (a norovirus surrogate) and poliovirus to infect cell cultures.

PubMed

McCann, K B; Lee, A; Wan, J; Roginski, H; Coventry, M J

2003-01-01

To characterize the effect of bovine lactoferrin and lactoferricin B against feline calicivirus (FCV), a norovirus surrogate and poliovirus (PV), as models for enteric viruses. Crandell-Reese feline kidney (CRFK) cells were used for the propagation of FCV and monkey embryo kidney (MEK) cells for PV. The assays included visual assessment of cell lines for cytopathic effects and determination of the percentage cell death using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium] dye reduction assay. Incubation of bovine lactoferrin with CRFK cells either prior to or together with FCV inoculation substantially reduced FCV infection. In contrast, the interference of lactoferrin with the infection of cells with PV was demonstrated only when lactoferrin was present with cell lines and virus for the entire assay period. Using indirect immunofluorescence, lactoferrin was detected on the surface of both CRFK and MEK cells, suggesting that the interference of viral infection may be attributed to lactoferrin binding to the surfaces of susceptible cells, thereby preventing the attachment of the virus particles. Lactoferricin B, a cationic antimicrobial peptide derived from the N-terminal domain of bovine lactoferrin, reduced FCV but not PV infection. Lactoferrin was shown to interfere with the infection of cells for both FCV and PV. However, lactoferricin B showed no interference of infection with PV and interference with infection for FCV required the presence of lactoferricin B together with the cell line and virus. An in vitro basis is provided for the effects of bovine lactoferrin and lactoferricin B in moderating food-borne infections of enteric viruses.

Development of a digital solar simulator based on full-bridge converter

NASA Astrophysics Data System (ADS)

Liu, Chen; Feng, Jian; Liu, Zhilong; Tong, Weichao; Ji, Yibo

2014-02-01

With the development of solar photovoltaic, distribution schemes utilized in power grid had been commonly application, and photovoltaic (PV) inverter is an essential equipment in grid. In this paper, a digital solar simulator based on full-bridge structure is presented. The output characteristic curve of system is electrically similar to silicon solar cells, which can greatly simplify research methods of PV inverter, improve the efficiency of research and development. The proposed simulator consists on a main control board based on TM320F28335, phase-shifted zero-voltage-switching (ZVS) DC-DC full-bridge converter and voltage and current sampling circuit, that allows emulating the voltage-current curve with the open-circuit voltage (Voc) of 900V and the short-circuit current (Isc) of 18A .When the system connected to a PV inverter, the inverter can quickly track from the open-circuit to the maximum power point and keep stability.

Challenging metastatic breast cancer with the natural defensin PvD1.

PubMed

Figueira, Tiago N; Oliveira, Filipa D; Almeida, Inês; Mello, Érica O; Gomes, Valdirene M; Castanho, Miguel A R B; Gaspar, Diana

2017-11-09

Metastatic breast cancer is a very serious life threatening condition that poses many challenges for the pharmaceutical development of effective chemotherapeutics. As the therapeutics targeted to the localized masses in breast improve, metastatic lesions in the brain slowly increase in their incidence compromising successful treatment outcomes overall. The blood-brain-barrier (BBB) is one important obstacle for the management of breast cancer brain metastases. New therapeutic approaches are in demand for overcoming the BBB's breaching by breast tumor cells. In this work we demonstrate the potential dual role of a natural antimicrobial plant defensin, PvD 1 : it interferes with the formation of solid tumors in the breast and concomitantly controls adhesion of breast cancer cells to human brain endothelial cells. We have used a combination of techniques that probe PvD 1 's effect at the single cell level and reveal that this peptide can effectively damage breast tumor cells, leaving healthy breast and brain cells unaffected. Results suggest that PvD1 quickly internalizes in cancer cells but remains located in the membrane of normal cells with no significant damage to its structure and biomechanical properties. These interactions in turn modulate cell adhesiveness between tumor and BBB cells. PvD 1 is a potential template for the design of innovative pharmacological approaches for metastatic breast cancer treatment: the manipulation of the biomechanical properties of tumor cells that ultimately prevent their attachment to the BBB.

InGaP/GaAs Inverted Dual Junction Solar Cells For CPV Applications Using Metal-Backed Epitaxial Lift-Off

NASA Astrophysics Data System (ADS)

Bauhuis, Gerard J.; Mulder, Peter; Haverkamp, Erik J.; Schermer, John J.; Nash, Lee J.; Fulgoni, Dominic J. F.; Ballard, Ian M.; Duggan, Geoffrey

2010-10-01

The epitaxial lift-off (ELO) technique has been combined with inverted III-V PV cell epitaxial growth with the aim of employing thin film PV cells in HCPV systems. In a stepwise approach to the realization of an inverted triple junction on a MELO platform we have first grown a GaAs single junction PV cell to establish the basic layer release process and cell processing steps followed by the growth, fabrication and test of an inverted InGaP/GaAs dual junction structure.

Genetic polymorphism and natural selection of Duffy binding protein of Plasmodium vivax Myanmar isolates

PubMed Central

2012-01-01

Background Plasmodium vivax Duffy binding protein (PvDBP) plays an essential role in erythrocyte invasion and a potential asexual blood stage vaccine candidate antigen against P. vivax. The polymorphic nature of PvDBP, particularly amino terminal cysteine-rich region (PvDBPII), represents a major impediment to the successful design of a protective vaccine against vivax malaria. In this study, the genetic polymorphism and natural selection at PvDBPII among Myanmar P. vivax isolates were analysed. Methods Fifty-four P. vivax infected blood samples collected from patients in Myanmar were used. The region flanking PvDBPII was amplified by PCR, cloned into Escherichia coli, and sequenced. The polymorphic characters and natural selection of the region were analysed using the DnaSP and MEGA4 programs. Results Thirty-two point mutations (28 non-synonymous and four synonymous mutations) were identified in PvDBPII among the Myanmar P. vivax isolates. Sequence analyses revealed that 12 different PvDBPII haplotypes were identified in Myanmar P. vivax isolates and that the region has evolved under positive natural selection. High selective pressure preferentially acted on regions identified as B- and T-cell epitopes of PvDBPII. Recombination may also be played a role in the resulting genetic diversity of PvDBPII. Conclusions PvDBPII of Myanmar P. vivax isolates displays a high level of genetic polymorphism and is under selective pressure. Myanmar P. vivax isolates share distinct types of PvDBPII alleles that are different from those of other geographical areas. These results will be useful for understanding the nature of the P. vivax population in Myanmar and for development of PvDBPII-based vaccine. PMID:22380592

NASA Glenn Research Center Solar Cell Experiment Onboard the International Space Station

NASA Technical Reports Server (NTRS)

Myers, Matthew G.; Wolford, David S.; Prokop, Norman F.; Krasowski, Michael J.; Parker, David S.; Cassidy, Justin C.; Davies , William E.; Vorreiter, Janelle O.; Piszczor, Michael F.; Mcnatt, Jeremiah S.;

Advances in Perovskite Solar Cells

PubMed Central

Zuo, Chuantian; Bolink, Henk J.; Han, Hongwei; Huang, Jinsong

2016-01-01

Organolead halide perovskite materials possess a combination of remarkable optoelectronic properties, such as steep optical absorption edge and high absorption coefficients, long charge carrier diffusion lengths and lifetimes. Taken together with the ability for low temperature preparation, also from solution, perovskite‐based devices, especially photovoltaic (PV) cells have been studied intensively, with remarkable progress in performance, over the past few years. The combination of high efficiency, low cost and additional (non‐PV) applications provides great potential for commercialization. Performance and applications of perovskite solar cells often correlate with their device structures. Many innovative device structures were developed, aiming at large‐scale fabrication, reducing fabrication cost, enhancing the power conversion efficiency and thus broadening potential future applications. This review summarizes typical structures of perovskite solar cells and comments on novel device structures. The applications of perovskite solar cells are discussed. PMID:27812475

Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Phillips, Brandon S.; Schneider, Todd A.; Vaughn, Jason A.; Wright, Kenneth H., Jr.

2015-01-01

To successfully operate a photovoltaic (PV) array system in space requires planning and testing to account for the effects of the space environment. It is critical to understand space environment interactions not only on the PV components, but also the array substrate materials, wiring harnesses, connectors, and protection circuitry (e.g. blocking diodes). Key elements of the space environment which must be accounted for in a PV system design include: Solar Photon Radiation, Charged Particle Radiation, Plasma, and Thermal Cycling. While solar photon radiation is central to generating power in PV systems, the complete spectrum includes short wavelength ultraviolet components, which photo-ionize materials, as well as long wavelength infrared which heat materials. High energy electron radiation has been demonstrated to significantly reduce the output power of III-V type PV cells; and proton radiation damages material surfaces - often impacting coverglasses and antireflective coatings. Plasma environments influence electrostatic charging of PV array materials, and must be understood to ensure that long duration arcs do not form and potentially destroy PV cells. Thermal cycling impacts all components on a PV array by inducing stresses due to thermal expansion and contraction. Given such demanding environments, and the complexity of structures and materials that form a PV array system, mission success can only be ensured through realistic testing in the laboratory. NASA's Marshall Space Flight Center has developed a broad space environment test capability to allow PV array designers and manufacturers to verify their system's integrity and avoid costly on-orbit failures. The Marshall Space Flight Center test capabilities are available to government, commercial, and university customers. Test solutions are tailored to meet the customer's needs, and can include performance assessments, such as flash testing in the case of PV cells.

Gelsolin: a novel thyroid hormone receptor-beta interacting protein that modulates tumor progression in a mouse model of follicular thyroid cancer.

PubMed

Kim, Caroline S; Furuya, Fumihiko; Ying, Hao; Kato, Yasuhito; Hanover, John A; Cheng, Sheue-yann

2007-03-01

Follicular thyroid cancer (FTC) is known to metastasize to distant sites via hematogenous spread; however, the underlying pathways that contribute to metastasis remain unknown. Recent creation of a knockin mutant mouse that expresses a mutant thyroid hormone receptor-beta (TRbeta(PV/PV) mouse) that spontaneously develops thyroid cancer with metastasis similar to humans has provided new opportunities to study contributors to FTC metastasis. This study evaluates the role of gelsolin, an actin-regulatory protein, in modulating the metastatic potential of FTC. Gelsolin was previously found by cDNA microarray analysis to be down-regulated in TRbeta(PV/PV) mice as compared with wild-type mice. This study found an age-dependent reduction of gelsolin protein abundance in TRbeta(PV/PV) mice as tumorigenesis progressed. Knockdown of gelsolin by small interfering RNA resulted in increased tumor cell motility and increased gelsolin expression by histone deacetylase inhibitor (trichostatin A) led to decreased cell motility. Additional biochemical analyses demonstrated that gelsolin physically interacted with TRbeta1 or PV in vivo and in vitro. The interaction regions were mapped to the C terminus of gelsolin and the DNA binding domain of TR. The physical interaction of gelsolin with PV reduced its binding to actin, leading to disarrayed cytoskeletal architectures. These results suggest that PV-induced alteration of the actin/gelsolin cytoskeleton contributes to increased cell motility. Thus, the present study uncovered a novel PV-mediated oncogenic pathway that could contribute to the local tumor progression and metastatic potential of thyroid carcinogenesis.

Influence of the morphology of organic heterojunction on the photovoltaic cell performance

NASA Astrophysics Data System (ADS)

Podhájecká, K.; Pfleger, J.

2006-12-01

We present a series of organic photovoltaic (PV) cells based on the bulk-distributed heterojunction where π -conjugated polymer poly[1-(4-trimethylsilylphenyl)-2-phenylvinylene], PSDPhV, acts as the donor upon photoexcitation and the substituted perylene based low-molecular-weight compound: N,N`-di(pent-3-yl)-perylene-3,4:9,10-bis(dicarboximide), DPe-PTCDI, as the acceptor of photogenerated electrons. According to both absorption spectra and AFM images of the thin films spin-coated from solution of DPe-PTCDI and PSDPhV in toluene, the DPe-PTCDI is molecularly dissolved in conjugated polymer matrix. Upon exposition of layers to toluene vapors, microcrystals of DPe-PTCDI are progressively formed. The influence of the morphology of DPe-PTCDI inside the polymer matrix on PV cell performance is investigated. This paper has been presented at “ECHOS06”, Paris, 28 30 juin 2006.

Quantum Efficiency and Bandgap Analysis for Combinatorial Photovoltaics: Sorting Activity of Cu–O Compounds in All-Oxide Device Libraries

PubMed Central

2014-01-01

All-oxide-based photovoltaics (PVs) encompass the potential for extremely low cost solar cells, provided they can obtain an order of magnitude improvement in their power conversion efficiencies. To achieve this goal, we perform a combinatorial materials study of metal oxide based light absorbers, charge transporters, junctions between them, and PV devices. Here we report the development of a combinatorial internal quantum efficiency (IQE) method. IQE measures the efficiency associated with the charge separation and collection processes, and thus is a proxy for PV activity of materials once placed into devices, discarding optical properties that cause uncontrolled light harvesting. The IQE is supported by high-throughput techniques for bandgap fitting, composition analysis, and thickness mapping, which are also crucial parameters for the combinatorial investigation cycle of photovoltaics. As a model system we use a library of 169 solar cells with a varying thickness of sprayed titanium dioxide (TiO2) as the window layer, and covarying thickness and composition of binary compounds of copper oxides (Cu–O) as the light absorber, fabricated by Pulsed Laser Deposition (PLD). The analysis on the combinatorial devices shows the correlation between compositions and bandgap, and their effect on PV activity within several device configurations. The analysis suggests that the presence of Cu4O3 plays a significant role in the PV activity of binary Cu–O compounds. PMID:24410367

Structurally designed attenuated subunit vaccines for S. aureus LukS-PV and LukF-PV confer protection in a mouse bacteremia model.

PubMed

Karauzum, Hatice; Adhikari, Rajan P; Sarwar, Jawad; Devi, V Sathya; Abaandou, Laura; Haudenschild, Christian; Mahmoudieh, Mahta; Boroun, Atefeh R; Vu, Hong; Nguyen, Tam; Warfield, Kelly L; Shulenin, Sergey; Aman, M Javad

2013-01-01

Previous efforts towards S. aureus vaccine development have largely focused on cell surface antigens to induce opsonophagocytic killing aimed at providing sterile immunity, a concept successfully applied to other Gram-positive pathogens such as Streptococcus pneumoniae. However, these approaches have largely failed, possibly in part due to the remarkable diversity of the staphylococcal virulence factors such as secreted immunosuppressive and tissue destructive toxins. S. aureus produces several pore-forming toxins including the single subunit alpha hemolysin as well as bicomponent leukotoxins such as Panton-Valentine leukocidin (PVL), gamma hemolysins (Hlg), and LukED. Here we report the generation of highly attenuated mutants of PVL subunits LukS-PV and LukF-PV that were rationally designed, based on an octameric structural model of the toxin, to be deficient in oligomerization. The attenuated subunit vaccines were highly immunogenic and showed significant protection in a mouse model of S. aureus USA300 sepsis. Protection against sepsis was also demonstrated by passive transfer of rabbit immunoglobulin raised against LukS-PV. Antibodies to LukS-PV inhibited the homologous oligomerization of LukS-PV with LukF-PV as well heterologous oligomerization with HlgB. Importantly, immune sera from mice vaccinated with the LukS mutant not only inhibited the PMN lytic activity produced by the PVL-positive USA300 but also blocked PMN lysis induced by supernatants of PVL-negative strains suggesting a broad protective activity towards other bicomponent toxins. These findings strongly support the novel concept of an anti-virulence, toxin-based vaccine intended for prevention of clinical S. aureus invasive disease, rather than achieving sterile immunity. Such a multivalent vaccine may include attenuated leukotoxins, alpha hemolysin, and superantigens.

PVMirror: A New Concept for Tandem Solar Cells and Hybrid Solar Converters

DOE PAGES

Yu, Zhengshan J.; Fisher, Kathryn C.; Wheelwright, Brian M.; ...

2015-08-25

As the solar electricity market has matured, energy conversion efficiency and storage have joined installed system cost as significant market drivers. In response, manufacturers of flatplate silicon photovoltaic (PV) cells have pushed cell efficiencies above 25%—nearing the 29.4% detailed-balance efficiency limit— and both solar thermal and battery storage technologies have been deployed at utility scale. This paper introduces a new tandem solar collector employing a “PVMirror” that has the potential to both increase energy conversion efficiency and provide thermal storage. A PVMirror is a concentrating mirror, spectrum splitter, and light-to-electricity converter all in one: It consists of a curved arrangementmore » of PV cells that absorb part of the solar spectrum and reflect the remainder to their shared focus, at which a second solar converter is placed. A strength of the design is that the solar converter at the focus can be of a radically different technology than the PV cells in the PVMirror; another is that the PVMirror converts a portion of the diffuse light to electricity in addition to the direct light. Here, we consider two case studies—a PV cell located at the focus of the PVMirror to form a four-terminal PV–PV tandem, and a thermal receiver located at the focus to form a PV–CSP (concentrating solar thermal power) tandem—and compare the outdoor energy outputs to those of competing technologies. PVMirrors can outperform (idealized) monolithic PV–PV tandems that are under concentration, and they can also generate nearly as much energy as silicon flat-plate PV while simultaneously providing the full energy storage benefit of CSP.« less

MATLAB Simulation of Photovoltaic and Photovoltaic/Thermal Systems Performance

NASA Astrophysics Data System (ADS)

Nasir, Farah H. M.; Husaini, Yusnira

2018-03-01

The efficiency of the photovoltaic reduces when the photovoltaic cell temperature increased due to solar irradiance. One solution is come up with the cooling system photovoltaic system. This combination is forming the photovoltaic-thermal (PV/T) system. Not only will it generate electricity also heat at the same time. The aim of this research is to focus on the modeling and simulation of photovoltaic (PV) and photovoltaic-thermal (PV/T) electrical performance by using single-diode equivalent circuit model. Both PV and PV/T models are developed in Matlab/Simulink. By providing the cooling system in PV/T, the efficiency of the system can be increased by decreasing the PV cell temperature. The maximum thermal, electrical and total efficiency values of PV/T in the present research are 35.18%, 15.56% and 50.74% at solar irradiance of 400 W/m2, mass flow rate of 0.05kgs-1 and inlet temperature of 25 °C respectively has been obtained. The photovoltaic-thermal shows that the higher efficiency performance compared to the photovoltaic system.

The status of lightweight photovoltaic space array technology based on amorphous silicon solar cells

NASA Astrophysics Data System (ADS)

Hanak, J. J.; Kaschmitter, J. L.

1991-05-01

An ultralight, flexible photovoltaic (PV) array of amorphous silicon (a-Si) has been identified as a potential low-cost power source for small satellites. We have conducted a survey of the status of the a-Si PV array technology with respect to present and future performance, availability, cost and risks. For existing, experimental array 'blankets' made of commercial cell material, utilizing metal foil substrates, the BOL performance at AM0 and 35 C includes total power up to 200 W, power per area of 64 W/sq m and power per weight of 258 W/kg. Doubling of power per weight occurs when polyimide substrates are used. Estimated EOL power output after 10 years in a nominal low-earth orbit would be 80 percent of BOL, the degradation being due to largely light-induced effects (minus 10 to minus 15 percent) and in part (minus 5 percent) to space radiation. Predictions for the year 1995 for flexible PV arrays, made on the basis of published results for rigid a-Si modules, indicate EOL power output per area and per weight of 105 W/sq m and 400 W/kg, respectively, while predictions for the late 1990s based on existing US national PV program goals indicate EOL values of 157 W/sq m and 600 W/kg. cost estimates by vendors for 200 W ultralight arrays in volume of over 1000 units range from $100/watt to $125/watt. Identified risks include the lack of flexible, space compatible encapsulant, the lack of space qualification effort, recent partial or full acquisitions of US manufacturers of a-Si cells by foreign firms, and the absence of a national commitment for a long-range development program toward developing of this important power source for space. One new US developer has emerged as a future potential supplier of a-Si PV devices on thin, polyimide substrates.

Comparison of Pyranometers and Reference Cells on Fixed and One-axis Tracking Surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooraghi, Michael R; Sengupta, Manajit; Vignola, Frank

Photovoltaic (PV) system perfomance is monitored by a wide variety of sensors. These instruments range from secondary standard pyranometers to photodiode-based pyranometers to reference cells. Although instruments are mounted in the plane of array of the modules a wide range of results have been obtained. Some of these difference have been assumed to come from systematic uncertainties associated with the irradiance sensors. This study is an attempt to quantify these differences by comparing the output of selected thermopile-based pyranometers to photodiode-based pyranometers and reference cells on a horizontal surface, a fixed-tilt surface, and a one-axis tracking surface. This analysis focusesmore » on clear-sky results from two sites with different climatic conditions. Several important features were observed. Photodiode-based pyranometers and reference cells produce widely different results under clear skies, especially at larger angles-of-incidence even though both instruments are based on measuring the short circuit current of solar cells. The difference is caused by the scattering of light as it passes through the glazing of the reference cell or the diffuser lens of the photodioded- base pyranometer. Both instruments are shown to have similar response to the spectral distribution of the irradiance when compared to the thermopile-based pyranometer that has a response nearly independent of the wavelength of light used by PV modules.« less

OUT Success Stories: Solar Roofing Shingles

DOE R&D Accomplishments Database

Johnson, N.

2000-08-01

Thin-film photovoltaic (PV) cells are now doubling as rooftop shingles. PV shingles offer many advantages. The energy generated from a building's PV rooftop shingles can provide power both to the building and the utility's power grid.

PV module mounting method and mounting assembly

DOEpatents

Lenox, Carl J.S.; Johnson, Kurt M.

2013-04-23

A method for mounting PV modules to a deck includes selecting PV module layout pattern so that adjacent PV module edges are spaced apart. PV mounting and support assemblies are secured to the deck according to the layout pattern using fasteners extending into the deck. The PV modules are placed on the PV mounting and support assemblies. Retaining elements are located over and secured against the upper peripheral edge surfaces of the PV modules so to secure them to the deck with the peripheral edges of the PV modules spaced apart from the deck. In some examples a PV module mounting assembly, for use on a shingled deck, comprises flashing, a base mountable on the flashing, a deck-penetrating fastener engageable with the base and securable to the deck so to secure the flashing and the base to the shingled deck, and PV module mounting hardware securable to the base.

A circuit-based photovoltaic module simulator with shadow and fault settings

NASA Astrophysics Data System (ADS)

Chao, Kuei-Hsiang; Chao, Yuan-Wei; Chen, Jyun-Ping

2016-03-01

The main purpose of this study was to develop a photovoltaic (PV) module simulator. The proposed simulator, using electrical parameters from solar cells, could simulate output characteristics not only during normal operational conditions, but also during conditions of partial shadow and fault conditions. Such a simulator should possess the advantages of low cost, small size and being easily realizable. Experiments have shown that results from a proposed PV simulator of this kind are very close to that from simulation software during partial shadow conditions, and with negligible differences during fault occurrence. Meanwhile, the PV module simulator, as developed, could be used on various types of series-parallel connections to form PV arrays, to conduct experiments on partial shadow and fault events occurring in some of the modules. Such experiments are designed to explore the impact of shadow and fault conditions on the output characteristics of the system as a whole.

Immunologic Control of Mus musculus Papillomavirus Type 1

PubMed Central

Peng, Shiwen; Chang, Yung-Nien; Hung, Chien-Fu; Roden, Richard B. S.

2015-01-01

Persistent papillomas developed in ~10% of out-bred immune-competent SKH-1 mice following MusPV1 challenge of their tail, and in a similar fraction the papillomas were transient, suggesting potential as a model. However, papillomas only occurred in BALB/c or C57BL/6 mice depleted of T cells with anti-CD3 antibody, and they completely regressed within 8 weeks after depletion was stopped. Neither CD4+ nor CD8+ T cell depletion alone in BALB/c or C57BL/6 mice was sufficient to permit visible papilloma formation. However, low levels of MusPV1 were sporadically detected by either genomic DNA-specific PCR analysis of local skin swabs or in situ hybridization of the challenge site with an E6/E7 probe. After switching to CD3+ T cell depletion, papillomas appeared upon 14/15 of mice that had been CD4+ T cell depleted throughout the challenge phase, 1/15 of CD8+ T cell depleted mice, and none in mice without any prior T cell depletion. Both control animals and those depleted with CD8-specific antibody generated MusPV1 L1 capsid-specific antibodies, but not those depleted with CD4-specific antibody prior to T cell depletion with CD3 antibody. Thus, normal BALB/c or C57BL/6 mice eliminate the challenge dose, whereas infection is suppressed but not completely cleared if their CD4 or CD8 T cells are depleted, and recrudescence of MusPV1 is much greater in the former following treatment with CD3 antibody, possibly reflecting their failure to generate capsid antibody. Systemic vaccination of C57BL/6 mice with DNA vectors expressing MusPV1 E6 or E7 fused to calreticulin elicits potent CD8 T cell responses and these immunodominant CD8 T cell epitopes were mapped. Adoptive transfer of a MusPV1 E6-specific CD8+ T cell line controlled established MusPV1 infection and papilloma in RAG1-knockout mice. These findings suggest the potential of immunotherapy for HPV-related disease and the importance of host immunogenetics in the outcome of infection. PMID:26495972

Interdigitated Back-Surface-Contact Solar Cell Modeling Using Silvaco Atlas

DTIC Science & Technology

2015-06-01

11 2. Solar Spectrum ...................................................................................13 3. PV Cell Efficiency...Figure 10. Spectrum of solar radiance, from [12]. 14 3. PV Cell Efficiency There are many factors that affect the efficiency of a solar cell. Metal...BACK-SURFACE-CONTACT SOLAR CELL MODELING USING SILVACO ATLAS by Shawn E. Green June 2015 Thesis Advisor: Sherif Michael Second Reader

Optimization of the silicon subcell for III-V on silicon multijunction solar cells: Key differences with conventional silicon technology

NASA Astrophysics Data System (ADS)

García-Tabarés, Elisa; Martín, Diego; García, Iván; Lelièvre, Jean François; Rey-Stolle, Ignacio

2012-10-01

Dual-junction solar cells formed by a GaAsP or GaInP top cell and a silicon (Si) bottom cell seem to be attractive candidates to materialize the long sought-for integration of III-V materials on Si for photovoltaic (PV) applications. Such integration would offer a cost breakthrough for PV technology, unifying the low cost of Si and the efficiency potential of III-V multijunction solar cells. The optimization of the Si solar cells properties in flat-plate PV technology is well-known; nevertheless, it has been proven that the behavior of Si substrates is different when processed in an MOVPE reactor In this study, we analyze several factors influencing the bottom subcell performance, namely, 1) the emitter formation as a result of phosphorus diffusion; 2) the passivation quality provided by the GaP nucleation layer; and 3) the process impact on the bottom subcell PV properties.

Coupling of Luminescent Solar Concentrators to Plasmonic Solar Cells

NASA Astrophysics Data System (ADS)

Wang, Shu-Yi

To make inexpensive solar cells is a continuous goal for solar photovoltaic (PV) energy industry. Thin film solar cells of various materials have been developed and continue to emerge in order to replace bulk silicon solar cells. A thin film solar cell not only uses less material but also requires a less expensive refinery process. In addition, other advantages coming along with small thickness are higher open circuit voltage and higher conversion efficiency. However, thin film solar cells, especially those made of silicon, have significant optical losses. In order to address this problem, this thesis investigates the spectral coupling of thin films PV to luminescent solar concentrators (LSC). LSC are passive devices, consisting of plastic sheets embedded with fluorescent dyes which absorb part of the incoming radiation spectrum and emit at specific wavelength. The emitted light is concentrated by total internal reflection to the edge of the sheet, where the PVs are placed. Since the light emitted from the LSC edge is usually in a narrow spectral range, it is possible to employ diverse strategies to enhance PV absorption at the peak of the emission wavelength. Employing plasmonic nanostructures has been shown to enhance absorption of thin films via forward scattering, diffraction and localized surface plasmon. These two strategies are theoretically investigated here for improving the absorption and elevating the output power of a thin film solar cell. First, the idea of spectral coupling of luminescent solar concentrators to plasmonic solar cells is introduced to assess its potential for increasing the power output. This study is carried out employing P3HT/PC60BM organic solar cells and LSC with Lumogen Red dyes. A simplified spectral coupling analysis is employed to predict the power density, considering the output spectrum of the LSC equivalent to the emission spectrum of the dye and neglecting any angular dependence. Plasmonic tuning is conducted to enhance absorption at the emission peak of the dye. A factorial increase in the output power density of coupled PV as compared to PV exposed directly to solar spectrum is observed for high light concentration on the edge. These initial results motivated a more in-depth study of coupled LSC-PV system, which took into account the radiative transport inside the realistic LSC. These investigations were carried out on LSCs using Lumogen Red305 and Rhodamine 6G dyes coupled to pristine and plasmonic ultra-thin film silicon solar cells. Prediction based on detailed balance shows that the coupled LSC-plasmonic solar cell can generate 63.7 mW/cm2 with a photocurrent density of 71.3 mA/cm2 which is higher than that of cSi solar cells available on current market. The second part of the thesis focuses on PV absorption enhancement techniques. First, the effect of vertical positioning of plasmonic nanostructures on absorption enhancement was theoretically investigated to understand which one of the three mechanisms usually responsible for the enhancement (forward scattering, diffraction and localized surface plamson) plays the dominant role. Simulation results suggested that the maximum enhancement occurred when placing the nanostructures in the rear side of the cell because of longer path length due to scattering. The experimental effort then switched focus on substrate patterning, which is a less expensive alternative to plasmonic absorption enhancement. Specifically, a nanostructured substrate was prepared by a simple electrochemical process based on two-step aluminum anodization technique. The absorption of thin film silicon deposited on these substrates showed a broadband enhancement. The overall photocurrent density was up to 40% higher than that of films deposited on flat substrates. In conclusion, the studies carried out in this thesis indicate that spectral coupling of LSCs to thin film solar cells could lead to significant improvements in PV output power density. Moreover, while the absorption of thin film solar cells can be enhanced by plasmonic nanostructures, it is shown that alternative methods, such as direct deposition of the films on inexpensively nanostructured substrates could also be employed to obtain significant enhancements. Combining these strategies may lead to inexpensive solar power harvesting systems with significant economic benefits. These strategies are not material-specific but applicable to a wide range of thin film solar cells.

Fluorescent magnetic bead-based mast cell biosensor for electrochemical detection of allergens in foodstuffs.

PubMed

Jiang, Donglei; Zhu, Pei; Jiang, Hui; Ji, Jian; Sun, Xiulan; Gu, Wenshu; Zhang, Genyi

2015-08-15

In this study, a novel electrochemical rat basophilic leukemia cell (RBL-2H3) cell sensor, based on fluorescent magnetic beads, has been developed for the detection and evaluation of different allergens in foodstuffs. Fluorescein isothiocyanate (FITC) was successfully fused inside the SiO2 layer of SiO2 shell-coated Fe3O4 nanoparticles, which was superior to the traditional Fe3O4@SiO2@FITC modification process. The as-synthesized fluorescent magnetic beads were then encapsulated with lipidosome to form cationic magnetic fluorescent nanoparticles (CMFNPs) for mast cell magnetofection. The CMFNPs were then characterized by SEM, TEM, VSM, FTIR, and XRD analyses, and transfected into RBL-2H3 cells through a highly efficient, lipid-mediated magnetofection procedure. Magnetic glassy carbon electrode (MGCE), which possesses excellent reproducibility and regeneration qualities, was then employed to adsorb the CMFNP-transfected RBL-2H3 cells activated by an allergen antigen for electrochemical assay. Results show that the exposure of model antigen-dinitrophenol-bovine serum albumin (DNP-BSA) to anti-DNP IgE-sensitized mast cells induced a robust and long-lasting electrochemical impedance signal in a dose-dependent manner. The detection limit was identified at 3.3×10(-4) ng/mL. To demonstrate the utility of this mast cell-based biosensor for detection of real allergens in foodstuffs, Anti-Pen a1 IgE and Anti-PV IgE-activated cells were employed to quantify both shrimp allergen tropomyosin (Pen a 1) and fish allergen parvalbumin (PV). Results show high detection accuracy for these targets, with a limit of 0.03 μg/mL (shrimp Pen a 1) and 0.16 ng/mL (fish PV), respectively. To this effect, we conclude the proposed method is a facile, highly sensitive, innovative electrochemical method for the evaluation of food allergens. Copyright © 2015 Elsevier B.V. All rights reserved.

Hybrid photovoltaic and thermoelectric module for high concentration solar system

NASA Astrophysics Data System (ADS)

Tamaki, Ryo; Toyoda, Takeshi; Tamura, Yoichi; Matoba, Akinari; Minamikawa, Toshiharu; Tokuda, Masayuki; Masui, Megumi; Okada, Yoshitaka

2017-09-01

A photovoltaic (PV) and thermoelectric (TE) hybrid module was developed for application to high concentration solar systems. The waste heat from the solar cells under concentrated light illumination was utilized to generate additional electricity by assembling TE devices below the multi-junction solar cells (MJSCs). Considering the high operating temperature of the PV and TE hybrid module compared with conventional concentrator PV modules, the TE device could compensate a part of the MJSC efficiency degradation at high temperature. The performance investigation clarified the feasibility of the hybrid PV and TE module under highly concentrated sunlight illumination.

Study of CdTe/CdS solar cell at low power density for low-illumination applications

NASA Astrophysics Data System (ADS)

Devi, Nisha; Aziz, Anver; Datta, Shouvik

2016-05-01

In this paper, we numerically investigate CdTe/CdS PV cell properties using a simulation program Solar Cell Capacitance Simulator in 1D (SCAPS-1D). A simple structure of CdTe PV cell has been optimized to study the effect of temperature, absorber thickness and work function at very low incident power. Objective of this research paper is to build an efficient and cost effective solar cell for portable electronic devices such as portable computers and cell phones that work at low incident power because most of such devices work at diffused and reflected sunlight. In this report, we simulated a simple CdTe PV cell at very low incident power, which gives good efficiency.

Nonhomologous recombination between defective poliovirus and coxsackievirus genomes suggests a new model of genetic plasticity for picornaviruses.

PubMed

Holmblat, Barbara; Jégouic, Sophie; Muslin, Claire; Blondel, Bruno; Joffret, Marie-Line; Delpeyroux, Francis

2014-08-05

Most of the circulating vaccine-derived polioviruses (cVDPVs) implicated in poliomyelitis outbreaks in Madagascar have been shown to be recombinants between the type 2 poliovirus (PV) strain of the oral polio vaccine (Sabin 2) and another species C human enterovirus (HEV-C), such as type 17 coxsackie A virus (CA17) in particular. We studied intertypic genetic exchanges between PV and non-PV HEV-C by developing a recombination model, making it possible to rescue defective type 2 PV RNA genomes with a short deletion at the 3' end by the cotransfection of cells with defective or infectious CA17 RNAs. We isolated over 200 different PV/CA17 recombinants, using murine cells expressing the human PV receptor (PVR) and selecting viruses with PV capsids. We found some homologous (H) recombinants and, mostly, nonhomologous (NH) recombinants presenting duplications of parental sequences preferentially located in the regions encoding proteins 2A, 2B, and 3A. Short duplications appeared to be stable, whereas longer duplications were excised during passaging in cultured cells or after multiplication in PVR-transgenic mice, generating H recombinants with diverse sites of recombination. This suggests that NH recombination events may be a transient, intermediate step in the generation and selection of the fittest H recombinants. In addition to the classical copy-choice mechanism of recombination thought to generate mostly H recombinants, there may also be a modular mechanism of recombination, involving NH recombinant precursors, shaping the genomes of recombinant enteroviruses and other picornaviruses. Importance: The multiplication of circulating vaccine-derived polioviruses (cVDPVs) in poorly immunized human populations can render these viruses pathogenic, causing poliomyelitis outbreaks. Most cVDPVs are intertypic recombinants between a poliovirus (PV) strain and another human enterovirus, such as type 17 coxsackie A viruses (CA17). For further studies of the genetic exchanges between PV and CA17, we have developed a model of recombination, making it possible to rescue defective PV RNA genomes with a short deletion by cotransfecting cells with the defective PV genome and CA17 genomic RNA. Numerous recombinants were found, including homologous PV/CA17 recombinants, but mostly nonhomologous recombinants presenting duplications of parental sequences preferentially located in particular regions. Long duplications were excised by passages in cultured cells or in mice, generating diverse homologous recombinants. Recombination leading to nonhomologous recombinants, which evolve into homologous recombinants, may therefore be seen as a model of genetic plasticity in enteroviruses and, possibly, in other RNA viruses. Copyright © 2014 Holmblat et al.

Developing High PV Penetration Cases for Frequency Response Study of U.S. Western Interconnection: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jin; Zhang, Yingchen; Veda, Santosh

Recent large penetrations of solar photovoltaic (PV) generation and the inertial characteristics of inverter-based generation technologies have caught the attention of those in the electric power industry in the United States. This paper presents a systematic approach to developing test cases of high penetrations of PV for the Western Interconnection. First, to examine the accuracy of the base case model, the Western Electricity Coordinating Council (WECC) model is validated by using measurement data from synchronized phasor measurement units. Based on the 2022 Light Spring case, we developed four high PV penetration cases for the WECC system that are of interestmore » to the industry: 5% PV+15 % wind, 25% PV+15% wind, 45% PV+15% wind, 65% PV+15% wind). Additionally, a method to project PV is proposed that is based on collected, realistic PV distribution information, including the current and future PV power plant locations and penetrations in the WECC system. Both the utility-scale PV plant and residential rooftop PV are included in this study.« less

Developing High PV Penetration Cases for Frequency Response Study of U.S. Western Interconnection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jin; Zhang, Yingchen; Veda, Santosh

Recent large penetrations of solar photovoltaic (PV) generation and the inertial characteristics of inverter-based generation technologies have caught the attention of those in the electric power industry in the United States. This paper presents a systematic approach to developing test cases of high penetrations of PV for the Western Interconnection. First, to examine the accuracy of the base case model, the Western Electricity Coordinating Council (WECC) model is validated by using measurement data from synchronized phasor measurement units. Based on the 2022 Light Spring case, we developed four high PV penetration cases for the WECC system that are of interestmore » to the industry: 5% PV+15 % wind, 25% PV+15% wind, 45% PV+15% wind, 65% PV+15% wind). Additionally, a method to project PV is proposed that is based on collected, realistic PV distribution information, including the current and future PV power plant locations and penetrations in the WECC system. Both the utility-scale PV plant and residential rooftop PV are included in this study.« less

Developing High PV Penetration Cases for Frequency Response Study of U.S. Western Interconnection: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jin; Zhang, Yingchen; Veda, Santosh

2017-04-11

Recent large penetrations of solar photovoltaic (PV) generation and the inertial characteristics of inverter-based generation technologies have caught the attention of those in the electric power industry in the United States. This paper presents a systematic approach to developing test cases of high penetrations of PV for the Western Interconnection. First, to examine the accuracy of the base case model, the Western Electricity Coordinating Council (WECC) model is validated by using measurement data from synchronized phasor measurement units. Based on the 2022 Light Spring case, we developed four high PV penetration cases for the WECC system that are of interestmore » to the industry: 5% PV+15 % wind, 25% PV+15% wind, 45% PV+15% wind, 65% PV+15% wind). Additionally, a method to project PV is proposed that is based on collected, realistic PV distribution information, including the current and future PV power plant locations and penetrations in the WECC system. Both the utility-scale PV plant and residential rooftop PV are included in this study.« less

Further Analyses of the NASA Glenn Research Center Solar Cell and Photovoltaic Materials Experiment Onboard the International Space Station

NASA Technical Reports Server (NTRS)

Myers, Matthew G.; Prokop, Norman F.; Krasowski, Michael J.; Piszczor, Michael F.; McNatt, Jeremiah S.

2016-01-01

Accurate air mass zero (AM0) measurement is essential for the evaluation of new photovoltaic (PV) technology for space solar cells. The NASA Glenn Research Center (GRC) has flown an experiment designed to measure the electrical performance of several solar cells onboard NASA Goddard Space Flight Center's (GSFC) Robotic Refueling Mission's (RRM) Task Board 4 (TB4) on the exterior of the International Space Station (ISS). Four industry and government partners provided advanced PV devices for measurement and orbital environment testing. The experiment was positioned on the exterior of the station for approximately eight months, and was completely self-contained, providing its own power and internal data storage. Several new cell technologies including four-junction (4J) Inverted Metamorphic Multi-Junction (IMM) cells were evaluated and the results will be compared to ground-based measurement methods.

Crystalline silicon solar cells with high resistivity emitter

NASA Astrophysics Data System (ADS)

Panek, P.; Drabczyk, K.; Zięba, P.

2009-06-01

The paper presents a part of research targeted at the modification of crystalline silicon solar cell production using screen-printing technology. The proposed process is based on diffusion from POCl3 resulting in emitter with a sheet resistance on the level of 70 Ω/□ and then, shaped by high temperature passivation treatment. The study was focused on a shallow emitter of high resistivity and on its influence on output electrical parameters of a solar cell. Secondary ion mass spectrometry (SIMS) has been employed for appropriate distinguishing the total donor doped profile. The solar cell parameters were characterized by current-voltage characteristics and spectral response (SR) methods. Some aspects playing a role in suitable manufacturing process were discussed. The situation in a photovoltaic industry with emphasis on silicon supply and current prices of solar cells, modules and photovoltaic (PV) systems are described. The economic and quantitative estimation of the PV world market is shortly discussed.

NF-E2 Overexpression Delays Erythroid Maturation and Increases Erythrocyte Production

PubMed Central

Mutschler, Manuel; Magin, Angela S.; Buerge, Martina; Roelz, Roland; Schanne, Daniel H.; Will, Britta; Pilz, Ingo H.; Migliaccio, Anna Rita; Pahl, Heike L.

2009-01-01

Summary The transcription factor Nuclear Factor-Erythroid 2 (NF-E2) is overexpressed in the vast majority of patients with polycythaemia vera (PV). In murine models, NF-E2 overexpression increases proliferation and promotes cellular viability in the absence of erythropoietin (EPO). EPO-independent growth is a hallmark of PV. We therefore hypothesized that NF-E2 overexpression contributes to erythrocytosis, the pathognomonic feature of PV. Consequently, we investigated the effect of NF-E2 overexpression in healthy CD34+ cells. NF-E2 overexpression led to a delay in erythroid maturation, manifested by a belated appearance of glycophorin A-positive erythroid precursors. Maturation delay was similarly observed in primary PV patient erythroid cultures compared to healthy controls. Protracted maturation led to a significant increase in the accumulated number of erythroid cells both in PV cultures and in CD34+ cells overexpressing NF-E2. Similarly, NF-E2 overexpression altered erythroid colony formation, leading to an increase in BFU-E formation. These data indicate that NF-E2 overexpression delays the early phase of erythroid maturation, resulting in an expansion of erythroid progenitors, thereby increasing the number of erythrocytes derived from one CD34+ cell. These data propose a role for NF-E2 in mediating the erythrocytosis of PV. PMID:19466964

77 FR 73018 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-07

...., Ltd. (Chengdu) PV Module Co., Ltd. Canadian Solar International Canadian Solar 24.48 Limited..... Chint Solar (Zhejiang) 24.48 Co., Ltd. Suzhou Shenglong PV-Tech Co., Ltd Suzhou Shenglong PV-TECH 24.48.... Jetion Solar (China) Co., Ltd.... Jetion Solar (China) 24.48 Co., Ltd. Jiangsu Green Power PV Co., Ltd...

Pediatric and Adult High-Grade Glioma Stem Cell Culture Models Are Permissive to Lytic Infection with Parvovirus H-1.

PubMed

Josupeit, Rafael; Bender, Sebastian; Kern, Sonja; Leuchs, Barbara; Hielscher, Thomas; Herold-Mende, Christel; Schlehofer, Jörg R; Dinsart, Christiane; Witt, Olaf; Rommelaere, Jean; Lacroix, Jeannine

2016-05-19

Combining virus-induced cytotoxic and immunotherapeutic effects, oncolytic virotherapy represents a promising therapeutic approach for high-grade glioma (HGG). A clinical trial has recently provided evidence for the clinical safety of the oncolytic parvovirus H-1 (H-1PV) in adult glioblastoma relapse patients. The present study assesses the efficacy of H-1PV in eliminating HGG initiating cells. H-1PV was able to enter and to transduce all HGG neurosphere culture models (n = 6), including cultures derived from adult glioblastoma, pediatric glioblastoma, and diffuse intrinsic pontine glioma. Cytotoxic effects induced by the virus have been observed in all HGG neurospheres at half maximal inhibitory concentration (IC50) doses of input virus between 1 and 10 plaque forming units per cell. H-1PV infection at this dose range was able to prevent tumorigenicity of NCH421k glioblastoma multiforme (GBM) "stem-like" cells in NOD/SCID mice. Interestingly NCH421R, an isogenic subclone with equal capacity of xenograft formation, but resistant to H-1PV infection could be isolated from the parental NCH421k culture. To reveal changes in gene expression associated with H-1PV resistance we performed a comparative gene expression analysis in these subclones. Several dysregulated genes encoding receptor proteins, endocytosis factors or regulators innate antiviral responses were identified and represent intriguing candidates for to further study molecular mechanisms of H-1PV resistance.

Parvalbumin-expressing interneurons can act solo while somatostatin-expressing interneurons act in chorus in most cases on cortical pyramidal cells.

PubMed

Safari, Mir-Shahram; Mirnajafi-Zadeh, Javad; Hioki, Hiroyuki; Tsumoto, Tadaharu

2017-10-06

Neural circuits in the cerebral cortex consist primarily of excitatory pyramidal (Pyr) cells and inhibitory interneurons. Interneurons are divided into several subtypes, in which the two major groups are those expressing parvalbumin (PV) or somatostatin (SOM). These subtypes of interneurons are reported to play distinct roles in tuning and/or gain of visual response of pyramidal cells in the visual cortex. It remains unclear whether there is any quantitative and functional difference between the PV → Pyr and SOM → Pyr connections. We compared unitary inhibitory postsynaptic currents (uIPSCs) evoked by electrophysiological activation of single presynaptic interneurons with population IPSCs evoked by photo-activation of a mass of interneurons in vivo and in vitro in transgenic mice in which PV or SOM neurons expressed channelrhodopsin-2, and found that at least about 14 PV neurons made strong connections with a postsynaptic Pyr cell while a much larger number of SOM neurons made weak connections. Activation or suppression of single PV neurons modified visual responses of postsynaptic Pyr cells in 6 of 7 pairs whereas that of single SOM neurons showed no significant modification in 8 of 11 pairs, suggesting that PV neurons can act solo whereas most of SOM neurons may act in chorus on Pyr cells.

PV_LIB Toolbox v. 1.3

DOE Office of Scientific and Technical Information (OSTI.GOV)

2015-12-09

PV_LIB comprises a library of Matlab? code for modeling photovoltaic (PV) systems. Included are functions to compute solar position and to estimate irradiance in the PV system's plane of array, cell temperature, PV module electrical output, and conversion from DC to AC power. Also included are functions that aid in determining parameters for module performance models from module characterization testing. PV_LIB is open source code primarily intended for research and academic purposes. All algorithms are documented in openly available literature with the appropriate references included in comments within the code.

Georgetown University Photovoltaic Higher Education National Exemplar Facility (PHENEF)

NASA Technical Reports Server (NTRS)

Marshall, N.

1984-01-01

Several photographs of this facility using photovoltaic (PV) cells are shown. An outline is given of the systems requirements, system design and wiring topology, a simplified block design, module electrical characteristics, PV module and PV module matching.

Progress with polycrystalline silicon thin-film solar cells on glass at UNSW

NASA Astrophysics Data System (ADS)

Aberle, Armin G.

2006-01-01

Polycrystalline Si (pc-Si) thin-film solar cells on glass have long been considered a very promising approach for lowering the cost of photovoltaic (PV) solar electricity. In recent years there have been dramatic advances with this PV technology, and the first commercial modules (CSG Solar) are expected to hit the marketplace in 2006. The CSG modules are based on solid-phase crystallisation of plasma-enhanced chemical vapor deposition (PECVD) -deposited amorphous Si. Independent research in the author's group at the University of New South Wales (UNSW) during recent years has led to the development of three alternative pc-Si thin-film solar cells on glass—EVA, ALICIA and ALICE. Cell thickness is generally about 2 μm. The first two cells are made by vacuum evaporation, whereas ALICE cells can be made by either vacuum evaporation or PECVD. Evaporation has the advantage of being a fast and inexpensive Si deposition method. A crucial component of ALICIA and ALICE cells is a seed layer made on glass by metal-induced crystallisation of amorphous silicon (a-Si). The absorber layer of these cells is made by either ion-assisted Si epitaxy (ALICIA) or solid-phase epitaxy of a-Si (ALICE). This paper reports on the status of these three new thin-film PV technologies. All three solar cells seem to be capable of voltages of over 500 mV and, owing to their potentially inexpensive and scalable fabrication process, have significant industrial appeal.

Calcium phosphate coupled Newcastle disease vaccine elicits humoral and cell mediated immune responses in chickens.

PubMed

Koppad, Sanganagouda; Raj, G Dhinakar; Gopinath, V P; Kirubaharan, J John; Thangavelu, A; Thiagarajan, V

2011-12-01

Calcium phosphate (CaP) particles were coupled with inactivated Newcastle disease virus (NDV) vaccine. The surface morphology of CaP particles coupled to NDV was found to be spherical, smooth and with a tendency to agglomerate. The mean (± SE) size of CaP particles was found 557.44 ± 18.62 nm. The mean percent encapsulation efficiency of CaP particles coupled to NDV assessed based on total protein content and haemagglutination (HA) activity in eluate was found to be 10.72 ± 0.89 and 12.50 ± 2.09, respectively. The humoral and cell mediated immune responses induced by CaP coupled NDV vaccine were assessed in comparison to a commercial live vaccine (RDV 'F'). CaP coupled NDV vaccine elicited prolonged haemagglutination inhibition (HI) and enzyme linked immunosorbent assay (ELISA) titres in the serum even at fourth and fifth week post-vaccination (PV), unlike RDV 'F' inoculated chickens whose titres declined to insignificant levels by this time. CaP coupled NDV vaccine could stimulate HI antibodies in tracheal washings and tears from second and first week PV, respectively. IgA ELISA antibodies were also seen in tracheal washings of these birds from third week PV and in tears from second week PV. CaP coupled NDV vaccine elicited cell mediated immune responses (CMI) from two to four weeks PV. The stimulation indices obtained after stimulation with specific antigen was not significantly different between CaP coupled antigen and live NDV virus except on first week PV. However, CaP coupled antigen did not cause suppression of lympo proliferation as indicated by statistically similar responses to mitogen, concanavalin A between the two groups. Overall, CaP coupled NDV vaccine elicited stronger and prolonged immune responses in comparison to the commercial live vaccine. No increase in the serum calcium and phosphorous levels were seen in CaP coupled NDV vaccine inoculated chickens. Copyright © 2010 Elsevier Ltd. All rights reserved.

Innovative architecture design for high performance organic and hybrid multi-junction solar cells

NASA Astrophysics Data System (ADS)

Li, Ning; Spyropoulos, George D.; Brabec, Christoph J.

2017-08-01

The multi-junction concept is especially attractive for the photovoltaic (PV) research community owing to its potential to overcome the Schockley-Queisser limit of single-junction solar cells. Tremendous research interests are now focused on the development of high-performance absorbers and novel device architectures for emerging PV technologies, such as organic and perovskite PVs. It has been predicted that the multi-junction concept is able to boost the organic and perovskite PV technologies approaching the 20% and 30% benchmarks, respectively, showing a bright future of commercialization of the emerging PV technologies. In this contribution, we will demonstrate innovative architecture design for solution-processed, highly functional organic and hybrid multi-junction solar cells. A simple but elegant approach to fabricating organic and hybrid multi-junction solar cells will be introduced. By laminating single organic/hybrid solar cells together through an intermediate layer, the manufacturing cost and complexity of large-scale multi-junction solar cells can be significantly reduced. This smart approach to balancing the photocurrents as well as open circuit voltages in multi-junction solar cells will be demonstrated and discussed in detail.

Visualization Based Data Mining for Comparison Between Two Solar Cell Libraries.

PubMed

Yosipof, Abraham; Kaspi, Omer; Majhi, Koushik; Senderowitz, Hanoch

2016-12-01

Material informatics may provide meaningful insights and powerful predictions for the development of new and efficient Metal Oxide (MO) based solar cells. The main objective of this paper is to establish the usefulness of data reduction and visualization methods for analyzing data sets emerging from multiple all-MOs solar cell libraries. For this purpose, two libraries, TiO 2 |Co 3 O 4 and TiO 2 |Co 3 O 4 |MoO 3 , differing only by the presence of a MoO 3 layer in the latter were analyzed with Principal Component Analysis and Self-Organizing Maps. Both analyses suggest that the addition of the MoO 3 layer to the TiO 2 |Co 3 O 4 library has affected the overall photovoltaic (PV) activity profile of the solar cells making the two libraries clearly distinguishable from one another. Furthermore, while MoO 3 had an overall favorable effect on PV parameters, a sub-population of cells was identified which were either indifferent to its presence or even demonstrated a reduction in several parameters. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reverse bias protected solar array with integrated bypass battery

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A (Inventor)

2012-01-01

A method for protecting the photovoltaic cells in a photovoltaic (PV) array from reverse bias damage by utilizing a rechargeable battery for bypassing current from a shaded photovoltaic cell or group of cells, avoiding the need for a bypass diode. Further, the method mitigates the voltage degradation of a PV array caused by shaded cells.

Frequency, clinicopathological features and phylogenetic analysis of feline morbillivirus in cats in Istanbul, Turkey.

PubMed

Yilmaz, Huseyin; Tekelioglu, Bilge K; Gurel, Aydin; Bamac, Ozge E; Ozturk, Gulay Y; Cizmecigil, Utku Y; Altan, Eda; Aydin, Ozge; Yilmaz, Aysun; Berriatua, Eduardo; Helps, Chris R; Richt, Juergen A; Turan, Nuri

2017-12-01

Objectives The aim of the study was to investigate feline morbillivirus (FmoPV) frequency, phylogeny and associated pathology in cats in Istanbul, Turkey. Methods Samples from sick (n = 96) and dead ( n = 15) cats were analysed using reverse transcription PCR. Blood and urine analyses and histopathology were also performed. Results FmoPV RNA was detected in six cats (5.4%), including three sick (in the urine) and three dead cats (tissues). A significantly greater proportion of FmoPV RNA-positive cats had street access compared with non-infected cats. Blood samples from the morbillivirus-positive cats were negative for morbillivirus RNA. Tubular parenchymal cells, lymphoid and plasma cells in kidney and hepatocytes, lymphoid and plasma cells in liver from dead cats were also positive by immunohistochemistry for the viral N protein. Two FmoPV-positive cats were also positive for feline coronavirus RNA and one cat for feline immunodeficiency virus RNA and feline leukaemia virus proviral DNA. Phylogenetic analysis of the six FmoPV-positive cats showed that the strains were grouped into cluster D and had high similarity (98.5-100%) with strains from Japan and Germany. In the three FmoPV RNA-positive sick cats, respiratory, urinary and digestive system signs were observed as well as weight loss, fever and depression in some cats. Similar clinical signs were also seen in the morbillivirus RNA-negative sick cats. FmoPV RNA-positive cats had lower median red blood cell count, haemoglobin, albumin, albumin/globulin and urobilinogen and higher alanine transaminase, alkaline phosphatase and bilirubin compared with non-infected cats. Significant histopathology of FmoPV RNA-positive dead cats included tubulointerstitial nephritis characterised by severe granular and vacuolar degeneration of the epithelial cells of the cortical and medullary tubules as well as mononuclear cell infiltrates. Widespread lymphoid cell infiltrates were detected in the renal cortex and medullary regions of the kidneys. Cellular infiltration, cholangiohepatitis and focal necrosis in the liver were also found. Although virus-infected cells were found in the kidney and liver of FmoRV RNA-positive cats, tubulointerstitial nephritis, cholangiohepatitis and focal necrosis seen in FmoRV RNA-positive cats were similar to those observed in FmoRV RNA-negative cats. Conclusions and relevance This is the first study to show the presence of FmoPV infection in cats in Turkey. Sick cats, particularly those with kidney disease, should be tested for this virus. The genotypes found in this study were similar to previously reported strains, indicating that circulating morbilliviruses in Turkey are conserved.

Investigating absence of optimal photovoltaics response in CZTS solar cell

NASA Astrophysics Data System (ADS)

Kumar, Atul; Thakur, Ajay D.

2018-05-01

Cu2ZnSnS4 (CZTS) has an optimal bandgap of 1.5eV. However contrary to expecting an optimal photovoltaic (PV) behavior is usually not seen from using solution processed approach. Here we try to understand the possible key reasons behind this based on the material attributes. The CZTS film is synthesized using two different solvents of Methoxy-ethanol and DMSO. The effect of air annealing and sulphurisation is studied on these two samples for their phase formation mechanism. XRD, TGA, Raman, UV-Vis, AFM and electrical characterization of the films are performed. A diode behavior is obtained in heterojunction of the CZTS/ZnO. Presence of secondary phases and interfacial recombination leads to poor PV behavior without any PV response.

77 FR 63791 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled into Modules, from the People's...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-17

...., Jiangsu Sunlink PV Technology Co., Ltd., and JA Solar Technology Yangzhou Co., Ltd. On June 25, 2012, Wuxi... (Chengdu) PV Tianwei New Energy 25.96 Module Co., Ltd. (Chengdu) PV Module Co., Ltd. Canadian Solar.... Chint Solar (Zhejiang) Co., Ltd Chint Solar (Zhejiang) 25.96 Co., Ltd. Suzhou Shenglong PV-Tech Co...

Experimental evidence for negative turgor pressure in small leaf cells of Robinia pseudoacacia L versus large cells of Metasequoia glyptostroboides Hu et W.C. Cheng. 2. Höfler diagrams below the volume of zero turgor and the theoretical implication for pressure-volume curves of living cells.

PubMed

Yang, Dongmei; Li, Junhui; Ding, Yiting; Tyree, Melvin T

2017-03-01

The physiological advantages of negative turgor pressure, P t , in leaf cells are water saving and homeostasis of reactants. This paper advances methods for detecting the occurrence of negative P t in leaves. Biomechanical models of pressure-volume (PV) curves predict that negative P t does not change the linearity of PV curve plots of inverse balance pressure, P B , versus relative water loss, but it does predict changes in either the y-intercept or the x-intercept of the plots depending on where cell collapse occurs in the P B domain because of negative P t . PV curve analysis of Robinia leaves revealed a shift in the x-intercept (x-axis is relative water loss) of PV curves, caused by negative P t of palisade cells. The low x-intercept of the PV curve was explained by the non-collapse of palisade cells in Robinia in the P B domain. Non-collapse means that P t smoothly falls from positive to negative values with decreasing cell volume without a dramatic change in slope. The magnitude of negative turgor in non-collapsing living cells was as low as -1.3 MPa and the relative volume of the non-collapsing cell equaled 58% of the total leaf cell volume. This study adds to the growing evidence for negative P t . © 2016 John Wiley & Sons Ltd.

Polyphenolics isolated from virgin coconut oil inhibits adjuvant induced arthritis in rats through antioxidant and anti-inflammatory action.

PubMed

Vysakh, A; Ratheesh, M; Rajmohanan, T P; Pramod, C; Premlal, S; Girish kumar, B; Sibi, P I

2014-05-01

We evaluated the protective efficacy of the polyphenolic fraction from virgin coconut oil (PV) against adjuvant induced arthritic rats. Arthritis was induced by intradermal injection of complete Freund's adjuvant. The activities of inflammatory, antioxidant enzymes and lipid peroxidation were estimated. PV showed high percentage of edema inhibition at a dose of 80mg/kg on 21st day of adjuvant arthritis and is non toxic. The expression of inflammatory genes such as COX-2, iNOS, TNF-α and IL-6 and the concentration of thiobarbituric acid reactive substance were decreased by treatment with PV. Antioxidant enzymes were increased and on treatment with PV. The increased level of total WBC count and C-reactive protein in the arthritic animals was reduced in PV treated rats. Synovial cytology showed that inflammatory cells and reactive mesothelial cells were suppressed by PV. Histopathology of paw tissue showed less edema formation and cellular infiltration on supplementation with PV. Thus the results demonstrated the potential beneficiary effect of PV on adjuvant induced arthritis in rats and the mechanism behind this action is due to its antioxidant and anti-inflammatory effects. Copyright © 2014 Elsevier B.V. All rights reserved.

Integrating DC/DC Conversion with Possible Reconfiguration within Submodule Solar Photovoltaic Systems

NASA Astrophysics Data System (ADS)

Huang, Peter Jen-Hung

This research first proposes a method to merge photovoltaic (PV) cells or PV panels within the internal components DC-DC converters. The purpose of this merged structure is to reconfigure the PV modules between series and parallel connections using high switching frequencies (hundreds of kHz). This leads to multi-levels of voltages and currents that become applied to the output filter of the converter. Further, this research introduces a concept of a switching cell that utilizes the reconfiguration of series and parallel connections in DC-DC converters. The switching occurs at high switching frequency and the switches can be integrated to be within the solar panels or in between the solar cells. The concept is generalized and applied to basic buck and boost topologies. As examples of the new types of converters: reconfigurable PV-buck and PV-boost converter topologies are presented. It is also possible to create other reconfigurable power converters: non-isolated and isolated topologies. Analysis, simulation and experimental verification for the reconfigurable PV-buck and PV-boost converters are presented extensively to illustrate proof of concept. Benefits and drawbacks of the new approach are discussed. The second part of this research proposes to utilize the internal solar cell capacitance and internal solar module wire parasitic inductances to replace the input capacitor and filter inductor in boost derived DC-DC converters for energy harvesting applications. High switching frequency (MHz) hard switched and resonant boost converters are proposed. Their analysis, simulation and experimental prototypes are presented. A specific proof-of-concept application is especially tested for foldable PV panels, which are known for their high internal wire inductance. The experimental converters successfully boost solar module voltage without adding any external input capacitance or filter inductor. Benefits and drawbacks of new proposed PV submodule integrated boost converters are discussed.

Histological Examination of Horse Chestnut Infection by Pseudomonas syringae pv. aesculi and Non-Destructive Heat Treatment to Stop Disease Progression

PubMed Central

de Keijzer, Jeroen; van den Broek, Lambertus A. M.; Ketelaar, Tijs; van Lammeren, André A. M.

2012-01-01

Since its emergence in Northwest Europe as a pathogen that infects trunks and branches of Aesculus spp. (the horse chestnuts) approximately one decade ago, Pseudomonas syringae pv. aesculi has rapidly established itself as major threat to these trees. Infected trees exhibit extensive necrosis of phloem and cambium, which can ultimately lead to dieback. The events after host entry leading to extensive necrosis are not well documented. In this work, the histopathology of this interaction is investigated and heat-treatment is explored as method to eradicate bacteria associated with established infections. The early wound-repair responses of A. hippocastanum, both in absence and presence of P. s. pv. aesculi, included cell wall lignification by a distinct layer of phloem and cortex parenchyma cells. The same cells also deposited suberin lamellae later on, suggesting this layer functions in compartmentalizing healthy from disrupted tissues. However, monitoring bacterial ingress, its construction appeared inadequate to constrain pathogen spread. Microscopic evaluation of bacterial dispersal in situ using immunolabelling and GFP-tagging of P. s. pv. aesculi, revealed two discriminative types of bacterial colonization. The forefront of lesions was found to contain densely packed bacteria, while necrotic areas housed bacterial aggregates with scattered individuals embedded in an extracellular matrix of bacterial origin containing alginate. The endophytic localization and ability of P. s. pv aesculi to create a protective matrix render it poorly accessible for control agents. To circumvent this, a method based on selective bacterial lethality at 39°C was conceived and successfully tested on A. hippocastanum saplings, providing proof of concept for controlling this disease by heat-treatment. This may be applicable for curing other tree cankers, caused by related phytopathogens. PMID:22808044

Histological examination of horse chestnut infection by Pseudomonas syringae pv. aesculi and non-destructive heat treatment to stop disease progression.

PubMed

de Keijzer, Jeroen; van den Broek, Lambertus A M; Ketelaar, Tijs; van Lammeren, André A M

2012-01-01

Since its emergence in Northwest Europe as a pathogen that infects trunks and branches of Aesculus spp. (the horse chestnuts) approximately one decade ago, Pseudomonas syringae pv. aesculi has rapidly established itself as major threat to these trees. Infected trees exhibit extensive necrosis of phloem and cambium, which can ultimately lead to dieback. The events after host entry leading to extensive necrosis are not well documented. In this work, the histopathology of this interaction is investigated and heat-treatment is explored as method to eradicate bacteria associated with established infections. The early wound-repair responses of A. hippocastanum, both in absence and presence of P. s. pv. aesculi, included cell wall lignification by a distinct layer of phloem and cortex parenchyma cells. The same cells also deposited suberin lamellae later on, suggesting this layer functions in compartmentalizing healthy from disrupted tissues. However, monitoring bacterial ingress, its construction appeared inadequate to constrain pathogen spread. Microscopic evaluation of bacterial dispersal in situ using immunolabelling and GFP-tagging of P. s. pv. aesculi, revealed two discriminative types of bacterial colonization. The forefront of lesions was found to contain densely packed bacteria, while necrotic areas housed bacterial aggregates with scattered individuals embedded in an extracellular matrix of bacterial origin containing alginate. The endophytic localization and ability of P. s. pv aesculi to create a protective matrix render it poorly accessible for control agents. To circumvent this, a method based on selective bacterial lethality at 39 °C was conceived and successfully tested on A. hippocastanum saplings, providing proof of concept for controlling this disease by heat-treatment. This may be applicable for curing other tree cankers, caused by related phytopathogens.

The status of lightweight photovoltaic space array technology based on amorphous silicon solar cells

NASA Technical Reports Server (NTRS)

Hanak, Joseph J.; Kaschmitter, Jim

1991-01-01

Ultralight, flexible photovoltaic (PV) array of amorphous silicon (a-Si) was identified as a potential low cost power source for small satellites. A survey was conducted of the status of the a-Si PV array technology with respect to present and future performance, availability, cost, and risks. For existing, experimental array blankets made of commercial cell material, utilizing metal foil substrates, the Beginning of Life (BOL) performance at Air Mass Zero (AM0) and 35 C includes total power up to 200 W, power per area of 64 W/sq m and power per weight of 258 W/kg. Doubling of power per weight occurs when polyimide substrates are used. Estimated End of Life (EOL) power output after 10 years in a nominal low earth orbit would be 80 pct. of BOL, the degradation being due to largely light induced effects (-10 to -15 pct.) and in part (-5 pct.) to space radiation. Predictions for the year 1995 for flexible PV arrays, made on the basis of published results for rigid a-Si modules, indicate EOL power output per area and per weight of 105 W/sq m and 400 W/kg, respectively, while predictions for the late 1990s based on existing U.S. national PV program goals indicate EOL values of 157 W/sq m and 600 W/kg. Cost estimates by vendors for 200 W ultralight arrays in volume of over 1000 units range from $100/watt to $125/watt. Identified risks include the lack of flexible, space compatible encapsulant, the lack of space qualification effort, recent partial or full acquisitions of US manufacturers of a-Si cells by foreign firms, and the absence of a national commitment for a long range development program toward developing of this important power source for space.

Quantitative analysis of poliomyelitis-like paralysis in mice induced by a poliovirus replicon.

PubMed

Arita, Minetaro; Nagata, Noriyo; Sata, Tetsutaro; Miyamura, Tatsuo; Shimizu, Hiroyuki

2006-11-01

Poliovirus (PV) infection causes severe paralysis, typically of the legs, by destruction of the motor neurons in the spinal cord. In this study, the relationship between PV replication in the spinal cord, damage in the motor neurons and poliomyelitis-like paralysis was analysed in transgenic mice expressing the human PV receptor (TgPVR21). First, a PV replicon encoding firefly luciferase in place of the capsid genes (PV-Fluc mc) was trans-encapsidated in 293T cells and the trans-encapsidated PV-Fluc mc (TE-PV-Fluc mc) was then inoculated into the spinal cords of TgPVR21 mice. TE-PV-Fluc mc was recovered with a titre of 6.3 x 10(7) infectious units ml(-1), which was comparable to those of PV1 strains. TgPVR21 mice inoculated with TE-PV-Fluc mc showed non-lethal paralysis of the hindlimbs, with severity ranging from a decline in grip strength to complete flaccid paralysis. The replication of TE-PV-Fluc mc in the spinal cord reached peak levels at 10 h post-inoculation (p.i.), followed by the appearance of paralysis at as early as 12 h p.i., reaching a plateau at 16 h p.i. Histological analysis showed a correlation between the lesion and the severity of the clinical symptoms in most mice. However, severe paralysis could also be observed with an apparently low lesion score, where as few as 5.3 x 10(2) motor neurons (1.4 % of the susceptible cells in the lumbar cord) were infected by TE-PV-Fluc mc. These results indicate that PV replication in a small population of the motor neurons was critical for severe residual poliomyelitis-like paralysis in TgPVR21 mice.

Final Technical Report for Automated Manufacturing of Innovative CPV/PV Modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okawa, David

Cogenra’s Dense Cell Interconnect system was designed to use traditional front-contact cells and string them together into high efficiency and high reliability “supercells”. This novel stringer allows one to take advantage of the ~100 GW/year of existing cell production capacity and create a solar product for the customer that will produce more power and last longer than traditional PV products. The goal for this program was for Cogenra Solar to design and develop a first-of-kind automated solar manufacturing line that produces strings of overlapping cells or “supercells” based on Cogenra’s Dense Cell Interconnect (DCI) technology for their Low Concentration Photovoltaicmore » (LCPV) systems. This will enable the commercialization of DCI technology to improve the efficiency, reliability and economics for their Low Concentration Photovoltaic systems. In this program, Cogenra Solar very successfully designed, developed, built, installed, and started up the ground-breaking manufacturing tools required to assemble supercells. Cogenra then successfully demonstrated operation of the integrated line at high yield and throughput far exceeding expectations. The development of a supercell production line represents a critical step toward a high volume and low cost Low Concentration Photovoltaic Module with Dense Cell Interconnect technology and has enabled the evaluation of the technology for reliability and yield. Unfortunately, performance and cost headwinds on Low Concentration Photovoltaics systems including lack of diffuse capture (10-15% hit) and more expensive tracker requirements resulted in a move away from LCPV technology. Fortunately, the versatility of Dense Cell Interconnect technology allows for application to flat plate module technology as well and Cogenra has worked with the DOE to utilize the learning from this grant to commercialize DCI technology for the solar market through the on-going grant: Catalyzing PV Manufacturing in the US With Cogenra Solar’s Next-Generation Dense Cell Interconnect PV Module Manufacturing Technology. This program is now very successfully building off of this work and commercializing the technology to enable increased solar adoption.« less

Cost and surface optimization of a remote photovoltaic system for two kinds of panels' technologies

NASA Astrophysics Data System (ADS)

Avril, S.; Arnaud, G.; Colin, H.; Montignac, F.; Mansilla, C.; Vinard, M.

2011-10-01

Stand alone photovoltaic (PV) systems comprise one of the promising electrification solutions to cover the demand of remote consumers, especially when it is coupled with a storage solution that would both increase the productivity of power plants and reduce the areas dedicated to energy production. This short communication presents a multi-objective design of a remote PV system coupled to battery and hydrogen storages systems simultaneously minimizing the total levelized cost and the occupied area, while fulfilling a constraint of consumer satisfaction. For this task, a multi-objective code based on particle swarm optimization has been used to find the best combination of different energy devices. Both short and mid terms based on forecasts assumptions have been investigated. An application for the site of La Nouvelle in the French overseas island of La Réunion is proposed. It points up a strong cost advantage by using Heterojunction with Intrinsic Thin layer (HIT) rather than crystalline silicon (c-Si) cells for the short term. However, the discrimination between these two PV cell technologies is less obvious for the mid term: a strong constraint on the occupied area will promote HIT, whereas a strong constraint on the cost will promote c-Si.

Distinct Physiological Maturation of Parvalbumin-Positive Neuron Subtypes in Mouse Prefrontal Cortex.

PubMed

Miyamae, Takeaki; Chen, Kehui; Lewis, David A; Gonzalez-Burgos, Guillermo

2017-05-10

Parvalbumin-positive (PV + ) neurons control the timing of pyramidal cell output in cortical neuron networks. In the prefrontal cortex (PFC), PV + neuron activity is involved in cognitive function, suggesting that PV + neuron maturation is critical for cognitive development. The two major PV + neuron subtypes found in the PFC, chandelier cells (ChCs) and basket cells (BCs), are thought to play different roles in cortical circuits, but the trajectories of their physiological maturation have not been compared. Using two separate mouse lines, we found that in the mature PFC, both ChCs and BCs are abundant in superficial layer 2, but only BCs are present in deeper laminar locations. This distinctive laminar distribution was observed by postnatal day 12 (P12), when we first identified ChCs by the presence of axon cartridges. Electrophysiology analysis of excitatory synapse development, starting at P12, showed that excitatory drive remains low throughout development in ChCs, but increases rapidly before puberty in BCs, with an earlier time course in deeper-layer BCs. Consistent with a role of excitatory synaptic drive in the maturation of PV + neuron firing properties, the fast-spiking phenotype showed different maturation trajectories between ChCs and BCs, and between superficial versus deep-layer BCs. ChC and BC maturation was nearly completed, via different trajectories, before the onset of puberty. These findings suggest that ChC and BC maturation may contribute differentially to the emergence of cognitive function, primarily during prepubertal development. SIGNIFICANCE STATEMENT Parvalbumin-positive (PV + ) neurons tightly control pyramidal cell output. Thus PV + neuron maturation in the prefrontal cortex (PFC) is crucial for cognitive development. However, the relative physiological maturation of the two major subtypes of PV + neurons, chandelier cells (ChCs) and basket cells (BCs), has not been determined. We assessed the maturation of ChCs and BCs in different layers of the mouse PFC, and found that, from early postnatal age, ChCs and BCs differ in laminar location. Excitatory synapses and fast-spiking properties matured before the onset of puberty in both cell types, but following cell type-specific developmental trajectories. Hence, the physiological maturation of ChCs and BCs may contribute to the emergence of cognitive function differentially, and predominantly during prepubertal development. Copyright © 2017 the authors 0270-6474/17/374883-20$15.00/0.

Design Approaches for Enhancing Photovoltaic Performance of Silicon Solar Cells Sensitized by Proximal Nanocrystalline Quantum Dots

NASA Astrophysics Data System (ADS)

Shafiq, Natis

Energy transfer (ET) based sensitization of silicon (Si) using proximal nanocrystal quantum dots (NQDs) has been studied extensively in recent years as a means to develop thin and flexible Si based solar cells. The driving force for this research activity is a reduction in materials cost. To date, the main method for determining the role of ET in sensitizing Si has been optical spectroscopic studies. The quantitative contribution from two modes of ET (namely, nonradiative and radiative) has been reported using time-resolved photoluminescence (TRPL) spectroscopy coupled with extensive theoretical modelling. Thus, optical techniques have established the potential for utilizing ET based sensitization of Si as a feasible way to develop novel NQD-Si hybrid solar cells. However, the ultimate measure of the efficiency of ET-based mechanisms is the generation of electron-hole pairs by the impinging photons. It is therefore important to perform electrical measurements. However, only a couple of studies have attempted electrical quantification of ET modes. A few studies have focused on photocurrent measurements, without considering industrially relevant photovoltaic (PV) systems. Therefore, there is a need to develop a systematic approach for the electrical quantification of ET-generated charges and to help engineer new PV architectures optimized for harnessing the full advantages of ET mechanisms. Within this context, the work presented in this dissertation aims to develop an experimental testing protocol that can be applied to different PV structures for quantifying ET contributions from electrical measurements. We fabricated bulk Si solar cells (SCs) as a test structure and utilized CdSe/ZnS NQDs for ET based sensitization. The NQD-bulk Si hybrid devices showed ˜30% PV enhancement after NQD deposition. We measured external quantum efficiency (EQE) of these devices to quantify ET-generated charges. Reflectance measurements were also performed to decouple contributions of intrinsic optical effects (i.e., anti-reflection) from NQD mediated ET processes. Our analysis indicates that the contribution of ET-generated charges cannot be detected by EQE measurements. Instead, changes in the optical properties (i.e., anti-reflection property) due to the NQD layer are found to be the primary source of the photocurrent enhancement. Based on this finding, we propose to minimize bulk Si absorption by using an ultrathin (˜300 nm) Si PV architecture which should enable measurements of ET-generated charges. We describe an optimized process flow for fabricating such ultrathin Si devices. The devices fabricated by this method behave like photo-detectors and show enhanced sensitivity under 1 Sun AM1.5G illumination. The geometry and process flow of these devices make it possible to incorporate NQDs for sensitization. Overall, this dissertation provides a protocol for the quantification of ET-generated charges and documents an optimized process flow for the development of an ultrathin Si solar cells.

When PV modules are becoming real building elements: White solar module, a revolution for BIPV (Presentation Recording)

NASA Astrophysics Data System (ADS)

Perret-Aebi, Laure-Emmanuelle; Escarré, Jordi; Li, Heng-Yu; Sansonnens, Laurent; Galliano, Federico; Cattaneo, Gianluca; Heinstein, Patrick; Nicolay, Sylvain; Bailat, Julien; Eberhard, Sébastien; Ballif, Christophe

2015-09-01

The use of photovoltaic (PV) is not anymore an option but a real need in the construction of nearly zero energy buildings. To date, the lack of PV products specifically designed for building integration, considering aesthetics and architectural aspects, is one important limiting factor allowing a massive deployment of PV in the built environment. Architects are continuously asking for new solutions to customize the colour of PV elements to better integrate them into the building skin. Among these colours, white is especially attractive as it is widely used in architecture for its elegance, versatility and fresh look. Until now, white solar modules were not considered to be an option and even never been though to be a technological possibility. Nonetheless, CSEM recently developed a new technology to make white solar modules a reality. Furthermore, the new Swiss company called Solaxess is now working on the industrialisation of this very innovative technology and the first products are expecting to be on the market at the end of 2015. The technology is based on the combination of two different elements: a solar cell able to convert solar infrared light into electricity and a selective filter which reflects and diffuse the whole visible spectrum. Any PV technology based on crystalline silicon can be used as they have a good response in the infrared. Approximately 55% of the current generated under standard test conditions comes from the infrared leading to conversion efficiencies above 11%. We will demonstrate, that thanks to this very innovative technology PV modules can become attractive and real active building elements and therefore meets the requirements of any future energy management through advanced building skins.

Polycythemia and Thrombocytosis.

PubMed

Parnes, Aric; Ravi, Arvind

2016-12-01

Myeloproliferative neoplasms (MPNs) are diseases of excess cell proliferation from bone marrow precursors. Two classic MPNs, polycythemia vera (PV) and essential thrombocytosis (ET), are conditions of excess proliferation of red blood cells and platelets, respectively. Although PV and ET involve different cells in the myeloid lineage, their clinical presentations have shared features, consistent with overlapping mutations in growth factor signaling. The management of both diseases involves minimizing the risk of thrombotic and hemorrhagic complications. Both PV and ET can progress to myelofibrosis or acute myeloid leukemia, portending a poor prognosis. MPNs can also present as primary myelofibrosis. Copyright © 2016 Elsevier Inc. All rights reserved.

Environmental Impacts from Photovoltaic Solar Cells Made with Single Walled Carbon Nanotubes.

PubMed

Celik, Ilke; Mason, Brooke E; Phillips, Adam B; Heben, Michael J; Apul, Defne

2017-04-18

An ex-ante life cycle inventory was developed for single walled carbon nanotube (SWCNT) PV cells, including a laboratory-made 1% efficient device and an aspirational 28% efficient four-cell tandem device. The environmental impact of unit energy generation from the mono-Si PV technology was used as a reference point. Compared to monocrystalline Si (mono-Si), the environmental impacts from 1% SWCNT was ∼18 times higher due mainly to the short lifetime of three years. However, even with the same short lifetime, the 28% cell had lower environmental impacts than mono-Si. The effects of lifetime and efficiency on the environmental impacts were further examined. This analysis showed that if the SWCNT device efficiency had the same value as the best efficiency of the material under comparison, to match the total normalized impacts of the mono- and poly-Si, CIGS, CdTe, and a-Si devices, the SWCNT devices would need a lifetime of 2.8, 3.5, 5.3, 5.1, and 10.8 years, respectively. It was also found that if the SWCNT PV has an efficiency of 4.5% or higher, its energy payback time would be lower than other existing and emerging PV technologies. The major impacts of SWCNT PV came from the cell's materials synthesis.

Characterization, antioxidant and immunomodulatory activities of polysaccharides from Prunella vulgaris Linn.

PubMed

Li, Chao; Huang, Qiang; Fu, Xiong; Yue, Xiu-Jie; Liu, Rui Hai; You, Li-Jun

2015-04-01

Water-soluble polysaccharides from Prunella vulgaris Linn (P. vulgaris) were fractionated using DEAE-Sepharose fast-flow column to obtain several eluents of water (PV-P1), 0.1M NaCl (PV-P2) and 0.2M NaCl (PV-P3). Structural analyses showed that PV-P1 had a higher molecular weight and degree of branching as compared to PV-P2 and PV-P3. Tertiary structure analyses indicated that PV-P1, PV-P2 and PV-P3 did not have triple-helical conformation. PV-P2 and PV-P3 showed stronger antioxidant activities than PV-P1, as measured radical scavenging capacities. PV-P1 showed stronger immunomodulatory activities than PV-P2 and PV-P3 in term of stimulation of the production of pro-inflammatory cytokines, including nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in murine macrophage RAW 264.7 cells. PV-P1, PV-P2 and PV-P3 did not exhibit cytotoxicities against RAW 264.7 at the concentrations tested. These results suggest that P. vulgaris polysaccharides could be explored as potential antioxidant and immunomodulatory agents for the complementary medicine or functional foods. Copyright © 2015 Elsevier B.V. All rights reserved.

Exceeding the solar cell Shockley-Queisser limit via thermal up-conversion of low-energy photons

NASA Astrophysics Data System (ADS)

Boriskina, Svetlana V.; Chen, Gang

2014-03-01

Maximum efficiency of ideal single-junction photovoltaic (PV) cells is limited to 33% (for 1 sun illumination) by intrinsic losses such as band edge thermalization, radiative recombination, and inability to absorb below-bandgap photons. This intrinsic thermodynamic limit, named after Shockley and Queisser (S-Q), can be exceeded by utilizing low-energy photons either via their electronic up-conversion or via the thermophotovoltaic (TPV) conversion process. However, electronic up-conversion systems have extremely low efficiencies, and practical temperature considerations limit the operation of TPV converters to the narrow-gap PV cells. Here we develop a conceptual design of a hybrid TPV platform, which exploits thermal up-conversion of low-energy photons and is compatible with conventional silicon PV cells by using spectral and directional selectivity of the up-converter. The hybrid platform offers sunlight-to-electricity conversion efficiency exceeding that imposed by the S-Q limit on the corresponding PV cells across a broad range of bandgap energies, under low optical concentration (1-300 suns), operating temperatures in the range 900-1700 K, and in simple flat panel designs. We demonstrate maximum conversion efficiency of 73% under illumination by non-concentrated sunlight. A detailed analysis of non-ideal hybrid platforms that allows for up to 15% of absorption/re-emission losses yields limiting efficiency value of 45% for Si PV cells.

Study of CdTe/CdS solar cell at low power density for low-illumination applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Devi, Nisha, E-mail: nishatanwer1989@gmail.com; Aziz, Anver, E-mail: aaziz@jmi.ac.in; Datta, Shouvik

In this paper, we numerically investigate CdTe/CdS PV cell properties using a simulation program Solar Cell Capacitance Simulator in 1D (SCAPS-1D). A simple structure of CdTe PV cell has been optimized to study the effect of temperature, absorber thickness and work function at very low incident power. Objective of this research paper is to build an efficient and cost effective solar cell for portable electronic devices such as portable computers and cell phones that work at low incident power because most of such devices work at diffused and reflected sunlight. In this report, we simulated a simple CdTe PV cellmore » at very low incident power, which gives good efficiency.« less

Preclinical Testing of an Oncolytic Parvovirus in Ewing Sarcoma: Protoparvovirus H-1 Induces Apoptosis and Lytic Infection In Vitro but Fails to Improve Survival In Vivo.

PubMed

Lacroix, Jeannine; Kis, Zoltán; Josupeit, Rafael; Schlund, Franziska; Stroh-Dege, Alexandra; Frank-Stöhr, Monika; Leuchs, Barbara; Schlehofer, Jörg R; Rommelaere, Jean; Dinsart, Christiane

2018-06-03

About 70% of all Ewing sarcoma (EWS) patients are diagnosed under the age of 20 years. Over the last decades little progress has been made towards finding effective treatment approaches for primarily metastasized or refractory Ewing sarcoma in young patients. Here, in the context of the search for novel therapeutic options, the potential of oncolytic protoparvovirus H-1 (H-1PV) to treat Ewing sarcoma was evaluated, its safety having been proven previously tested in adult cancer patients and its oncolytic efficacy demonstrated on osteosarcoma cell cultures. The effects of viral infection were tested in vitro on four human Ewing sarcoma cell lines. Notably evaluated were effects of the virus on the cell cycle and its replication efficiency. Within 24 h after infection, the synthesis of viral proteins was induced. Efficient H-1PV replication was confirmed in all four Ewing sarcoma cell lines. The cytotoxicity of the virus was determined on the basis of cytopathic effects, cell viability, and cell lysis. These in vitro experiments revealed efficient killing of Ewing sarcoma cells by H-1PV at a multiplicity of infection between 0.1 and 5 plaque forming units (PFU)/cell. In two of the four tested cell lines, significant induction of apoptosis by H-1PV was observed. H-1PV thus meets all the in vitro criteria for a virus to be oncolytic towards Ewing sarcoma. In the first xenograft experiments, however, although an antiproliferative effect of intratumoral H-1PV injection was observed, no significant improvement of animal survival was noted. Future projects aiming to validate parvovirotherapy for the treatment of pediatric Ewing sarcoma should focus on combinatorial treatments and will require the use of patient-derived xenografts and immunocompetent syngeneic animal models.

Wafer integrated micro-scale concentrating photovoltaics

NASA Astrophysics Data System (ADS)

Gu, Tian; Li, Duanhui; Li, Lan; Jared, Bradley; Keeler, Gordon; Miller, Bill; Sweatt, William; Paap, Scott; Saavedra, Michael; Das, Ujjwal; Hegedus, Steve; Tauke-Pedretti, Anna; Hu, Juejun

2017-09-01

Recent development of a novel micro-scale PV/CPV technology is presented. The Wafer Integrated Micro-scale PV approach (WPV) seamlessly integrates multijunction micro-cells with a multi-functional silicon platform that provides optical micro-concentration, hybrid photovoltaic, and mechanical micro-assembly. The wafer-embedded micro-concentrating elements is shown to considerably improve the concentration-acceptance-angle product, potentially leading to dramatically reduced module materials and fabrication costs, sufficient angular tolerance for low-cost trackers, and an ultra-compact optical architecture, which makes the WPV module compatible with commercial flat panel infrastructures. The PV/CPV hybrid architecture further allows the collection of both direct and diffuse sunlight, thus extending the geographic and market domains for cost-effective PV system deployment. The WPV approach can potentially benefits from both the high performance of multijunction cells and the low cost of flat plate Si PV systems.

Insolation-oriented model of photovoltaic module using Matlab/Simulink

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsai, Huan-Liang

2010-07-15

This paper presents a novel model of photovoltaic (PV) module which is implemented and analyzed using Matlab/Simulink software package. Taking the effect of sunlight irradiance on the cell temperature, the proposed model takes ambient temperature as reference input and uses the solar insolation as a unique varying parameter. The cell temperature is then explicitly affected by the sunlight intensity. The output current and power characteristics are simulated and analyzed using the proposed PV model. The model verification has been confirmed through an experimental measurement. The impact of solar irradiation on cell temperature makes the output characteristic more practical. In addition,more » the insolation-oriented PV model enables the dynamics of PV power system to be analyzed and optimized more easily by applying the environmental parameters of ambient temperature and solar irradiance. (author)« less

The possibility of developing hybrid PV/T solar system

NASA Astrophysics Data System (ADS)

Dobrnjac, M.; Zivkovic, P.; Babic, V.

2017-05-01

An alternative and cost-effective solution to developing integrated PV system is to use hybrid photovoltaic/thermal (PV/T) solar system. The temperature of PV modules increases due to the absorbed solar radiation that is not converted into electricity, causing a decrease in their efficiency. In hybrid PV/T solar systems the reduction of PV module temperature can be combined with a useful fluid heating. In this paper we present the possibility of developing a new hybrid PV/T solar system. Hybrid PV/T system can provide electrical and thermal energy, thus achieving a higher energy conversion rate of the absorbed solar radiation. We developed PV/T prototype consisted of commercial PV module and thermal panel with our original solution of aluminium absorber with special geometric shapes. The main advantages of our combined PV/T system are: removing of heat from the PV panel; extending the lifetime of photovoltaic cells; excess of the removing heat from PV part is used to heat the fluid in the thermal part of the panel; the possibility of using on the roof and facade constructions because less weight.

Performance comparison investigation on solar photovoltaic-thermoelectric generation and solar photovoltaic-thermoelectric cooling hybrid systems under different conditions

NASA Astrophysics Data System (ADS)

Wu, Shuang-Ying; Zhang, Yi-Chen; Xiao, Lan; Shen, Zu-Guo

2018-07-01

The performance of solar photovoltaic-thermoelectric generation hybrid system (PV-TGS) and solar photovoltaic-thermoelectric cooling hybrid system (PV-TCS) under different conditions were theoretically analysed and compared. To test the practicality of these two hybrid systems, the performance of stand-alone PV system was also studied. The results show that PV-TGS and PV-TCS in most cases will result in the system with a better performance than stand-alone PV system. The advantage of PV-TGS is emphasised in total output power and conversion efficiency which is even poorer in PV-TCS than that in stand-alone PV system at the ambient wind speed uw being below 3 m/s. However, PV-TCS has obvious advantage on lowering the temperature of PV cell. There is an obvious increase in tendency on the performance of PV-TGS and PV-TCS when the cooling capacity of two hybrid systems varies from around 0.06 to 0.3 W/K. And it is also proved that not just a-Si in PV-TGS can produce a better performance than the stand-alone PV system alone at most cases.

ANN based Real-Time Estimation of Power Generation of Different PV Module Types

NASA Astrophysics Data System (ADS)

Syafaruddin; Karatepe, Engin; Hiyama, Takashi

Distributed generation is expected to become more important in the future generation system. Utilities need to find solutions that help manage resources more efficiently. Effective smart grid solutions have been experienced by using real-time data to help refine and pinpoint inefficiencies for maintaining secure and reliable operating conditions. This paper proposes the application of Artificial Neural Network (ANN) for the real-time estimation of the maximum power generation of PV modules of different technologies. An intelligent technique is necessary required in this case due to the relationship between the maximum power of PV modules and the open circuit voltage and temperature is nonlinear and can't be easily expressed by an analytical expression for each technology. The proposed ANN method is using input signals of open circuit voltage and cell temperature instead of irradiance and ambient temperature to determine the estimated maximum power generation of PV modules. It is important for the utility to have the capability to perform this estimation for optimal operating points and diagnostic purposes that may be an early indicator of a need for maintenance and optimal energy management. The proposed method is accurately verified through a developed real-time simulator on the daily basis of irradiance and cell temperature changes.

Flow Cytometric Determination of Panton-Valentine Leucocidin S Component Binding

PubMed Central

Gauduchon, Valérie; Werner, Sandra; Prévost, Gilles; Monteil, Henri; Colin, Didier A.

2001-01-01

The binding of the S component (LukS-PV) from the bicomponent staphylococcal Panton-Valentine leucocidin to human polymorphonuclear neutrophils (PMNs) and monocytes was determined using flow cytometry and a single-cysteine substitution mutant of LukS-PV. The mutant was engineered by replacing a glycine at position 10 with a cysteine and was labeled with a fluorescein moiety. The biological activity of the mutant was identical to that of the native protein. It has been shown that LukS-PV has a high affinity for PMNs (Kd = 0.07 ± 0.02 nM, n = 5) and monocytes (Kd = 0.020 ± 0.003 nM, n = 3) with maximal binding capacities of 197,000 and 80,000 LukS-PV molecules per cell, respectively. The nonspecifically bound molecules of LukS-PV do not form pores in the presence of the F component (LukF-PV) of leucocidin. LukS-PV and HlgC share the same receptor on PMNs, but the S components of other staphylococcal leukotoxins, HlgA, LukE, and LukM, do not compete with LukS-PV for its receptor. Extracellular Ca2+ at physiological concentrations (1 to 2 nM) has only a slight influence on the LukS-PV binding, in contrast to its complete inhibition by Zn2+. The down-regulation by phorbol 12-myristate 13-acetate (PMA) of the binding of LukS-PV was blocked by staurosporine, suggesting that the regulatory effect of PMA depends on protein kinase C activation. The labeled mutant form of LukS-PV has proved very useful for detailed binding studies of circulating white cells by flow cytometry. LukS-PV possesses a high specific affinity for a unique receptor on PMNs and monocytes. PMID:11254598

Practical considerations for solar energy thermally enhanced photo-luminescence (TEPL) (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kruger, Nimrod; Manor, Assaf; Kurtulik, Matej; Sabapathy, Tamilarasan; Rotschild, Carmel

2017-04-01

While single-junction photovoltaics (PV's) are considered limited in conversion efficiency according to the Shockley-Queisser limit, concepts such as solar thermo-photovoltaics aim to harness lost heat and overcome this barrier. We claim the novel concept of Thermally Enhanced Photoluminescence (TEPL) as an easier route to achieve this goal. Here we present a practical TEPL device where a thermally insulated photo-luminescent (PL) absorber, acts as a mediator between a photovoltaic cell and the sun. This high temperature absorber emits blue-shifted PL at constant flux, then coupled to a high band gap PV cell. This scheme promotes PV conversion efficiencies, under ideal conditions, higher than 62% at temperatures lower than 1300K. Moreover, for a PV and absorber band-gaps of 1.45eV (GaAs PV's) and 1.1eV respectively, under practical conditions, solar concentration of 1000 suns, and moderate thermal insulation; the conversion efficiencies potentially exceed 46%. Some of these practical conditions belong to the realm of optical design; including high photon recycling (PR) and absorber external quantum efficiency (EQE). High EQE values, a product of the internal QE of the active PL materials and the extraction efficiency of each photon (determined by the absorber geometry and interfaces), have successfully been reached by experts in laser cooling technology. PR is the part of emitted low energy photons (in relation to the PV band-gap) that are reabsorbed and consequently reemitted with above band-gap energies. PV back-reflector reflectivity, also successfully achieved by those who design the cutting edge high efficiency PV cells, plays a major role here.

Cytokine signatures of innate and adaptive immunity in 17DD yellow fever vaccinated children and its association with the level of neutralizing antibody.

PubMed

Luiza-Silva, Maria; Campi-Azevedo, Ana Carolina; Batista, Maurício Azevedo; Martins, Marina Angela; Avelar, Renato Sathler; da Silveira Lemos, Denise; Bastos Camacho, Luiz Antonio; de Menezes Martins, Reinaldo; de Lourdes de Sousa Maia, Maria; Guedes Farias, Roberto Henrique; da Silva Freire, Marcos; Galler, Ricardo; Homma, Akira; Leite Ribeiro, José Geraldo; Campos Lemos, Jandira Aparecida; Auxiliadora-Martins, Maria; Eloi-Santos, Silvana Maria; Teixeira-Carvalho, Andréa; Martins-Filho, Olindo Assis

2011-09-15

The live attenuated yellow fever (YF) vaccines have been available for decades and are considered highly effective and one of the safest vaccines worldwide. The impact of YF-17DD-antigens recall on cytokine profiles of YF-17DD-vaccinated children were characterized using short-term cultures of whole blood samples and single-cell flow cytometry. This study enrolled seroconverters and nonseroconverters after primovaccination (PV-PRNT⁺ and PV-PRNT⁻), seroconverters after revaccination (RV-PRNT⁺), and unvaccinated volunteers (UV-PRNT⁻). The analysis demonstrated in the PV-PRNT⁺ group a balanced involvement of pro-inflammatory/regulatory adaptive immunity with a prominent participation of innate immunity pro-inflammatory events (IL-12⁺ and TNF-α⁺ NEU and MON). Using the PV-PRNT⁺ cytokine signature as a reference profile, PV-PRNT⁻ presented a striking lack of innate immunity proinflammatory response along with an increased adaptive regulatory profile (IL-4⁺CD4⁺ T cells and IL-10⁺ and IL-5⁺CD8⁺ T cells). Conversely, the RV-PRNT⁺ shifted the overall cytokine signatures toward an innate immunity pro-inflammatory profile and restored the adaptive regulatory response. The data demonstrated that the overall cytokine signature was associated with the levels of PRNT antibodies with a balanced innate/adaptive immunity with proinflammatory/regulatory profile as the hallmark of PV-PRNT(MEDIUM⁺), whereas a polarized regulatory response was observed in PV-PRNT⁻ and a prominent proinflammatory signature was the characteristic of PV-PRNT(HIGH⁺).

Hybrid photovoltaic/thermal (PV/T) solar systems simulation with Simulink/Matlab

DOE Office of Scientific and Technical Information (OSTI.GOV)

da Silva, R.M.; Fernandes, J.L.M.

The purpose of this work consists in thermodynamic modeling of hybrid photovoltaic-thermal (PV/T) solar systems, pursuing a modular strategy approach provided by Simulink/Matlab. PV/T solar systems are a recently emerging solar technology that allows for the simultaneous conversion of solar energy into both electricity and heat. This type of technology present some interesting advantages over the conventional ''side-by-side'' thermal and PV solar systems, such as higher combined electrical/thermal energy outputs per unit area, and a more uniform and aesthetical pleasant roof area. Despite the fact that early research on PV/T systems can be traced back to the seventies, only recentlymore » it has gained a renewed impetus. In this work, parametric studies and annual transient simulations of PV/T systems are undertaken in Simulink/Matlab. The obtained results show an average annual solar fraction of 67%, and a global overall efficiency of 24% (i.e. 15% thermal and 9% electrical), for a typical four-person single-family residence in Lisbon, with p-Si cells, and a collector area of 6 m{sup 2}. A sensitivity analysis performed on the PV/T collector suggests that the most important variable that should be addressed to improve thermal performance is the photovoltaic (PV) module emittance. Based on those results, some additional improvements are proposed, such as the use of vacuum, or a noble gas at low-pressure, to allow for the removal of PV cells encapsulation without air oxidation and degradation, and thus reducing the PV module emittance. Preliminary results show that this option allows for an 8% increase on optical thermal efficiency, and a substantial reduction of thermal losses, suggesting the possibility of working at higher fluid temperatures. The higher working temperatures negative effect in electrical efficiency was negligible, due to compensation by improved optical properties. The simulation results are compared with experimental data obtained from other authors and perform reasonably well. The Simulink modeling platform has been mainly used worldwide on simulation of control systems, digital signal processing and electric circuits, but there are very few examples of application to solar energy systems modeling. This work uses the modular environment of Simulink/Matlab to model individual PV/T system components, and to assemble the entire installation layout. The results show that the modular approach strategy provided by Matlab/Simulink environment is applicable to solar systems modeling, providing good code scalability, faster developing time, and simpler integration with external computational tools, when compared with traditional imperative-oriented programming languages. (author)« less

Bifacial PV cell with reflector for stand-alone mast for sensor powering purposes

NASA Astrophysics Data System (ADS)

Jakobsen, Michael L.; Thorsteinsson, Sune; Poulsen, Peter B.; Riedel, N.; Rødder, Peter M.; Rødder, Kristin

2017-09-01

Reflectors to bifacial PV-cells are simulated and prototyped in this work. The aim is to optimize the reflector to specific latitudes, and particularly northern latitudes. Specifically, by using minimum semiconductor area the reflector must be able to deliver the electrical power required at the condition of minimum solar travel above the horizon, worst weather condition etc. We will test a bifacial PV-module with a retroreflector, and compare the output with simulations combined with local solar data.

Perovskite Solar Cells | Photovoltaic Research | NREL

Science.gov Websites

& Devices pages: High-Efficiency Crystalline PV Polycrystalline Thin-Film PV Perovskite and Organic -Defect Hybrid Organic/Inorganic Perovskite Films as PV Absorbers. (FY 2015FY 2016). In collaboration with organic metal halide perovskite (see article). Ultrahigh-Efficiency and Low-Cost Polycrystalline Halide

Low-cost photovoltaics: Luminescent solar concentrators and colloidal quantum dot solar cells

NASA Astrophysics Data System (ADS)

Leow, Shin Woei

Solar energy has long been lauded as an inexhaustible fuel source with more energy reaching the earth's surface in one hour than the global consumption for a year. Although capable of satisfying the world's energy requirements, solar energy remains an expensive technology that has yet to attain grid parity. Another drawback is that existing solar farms require large quantities of land in order to generate power at useful rates. In this work, we look to luminescent solar concentrator systems and quantum dot technology as viable solutions to lowering the cost of solar electricity production with the flexibility to integrate such technologies into buildings to achieve dual land use. Luminescent solar concentrator (LSC) windows with front-facing photovoltaic (PV) cells were built and their gain and power efficiency were investigated. Conventional LSCs employ a photovoltaic (PV) cell that is placed on the edge of the LSC, facing inward. This work describes a new design with the PV cells on the front-face allowing them to receive both direct solar irradiation and wave-guided photons emitted from a dye embedded in an acrylic sheet, which is optically coupled to the PV cells. Parameters investigated include the thickness of the waveguide, edge treatment of the window, cell width, and cell placement. The data allowed us to make projections that aided in designing windows for maximized overall efficiency. A gain in power of 2.2x over the PV cells alone was obtained with PV cell coverage of 5%, and a power conversion efficiency as high as 6.8% was obtained with a PV cell coverage of 31%. Balancing the trade-offs between gain and efficiency, the design with the lowest cost per watt attained a power efficiency of 3.8% and a gain of 1.6x. With the viability of the LSC demonstrated, a weighted Monte-Carlo Ray Tracing program was developed to study the transport of photons and loss mechanisms in the LSC to aid in design optimization. The program imports measured absorption/emission spectra of an organic luminescent dye (LR305), the transmission coefficient and refractive index of acrylic as parameters that describe the system. Simulations suggest that for LR305, 8-10cm of luminescent material surrounding the PV cell yields the highest increase in power gain per unit area of LSC added, thereby determining the ideal spacing between PV cells in the panel. The model also predicts that for different PV cell dimensions, there exists an optimum waveguide thickness which efficiently transports photon collected by the waveguide to the PV cell with minimal loss, and maintains an even distribution of photons across the cell surface. For the case of the 12.5 by 1cm rectangular cells used in this work, the calculated waveguide thickness is 3mm. For larger cells, every 1cm increment in PV cell width should be accompanied by a 0.75mm increase in waveguide thickness to preserve peak performance. In line with the goal of pushing for cost competitive photovoltaics, the last part of this work shifts to the study of colloidal quantum dot solar cells. A combination of low temperature, highly scalable fabrication process and reduced material usage for thin films offers us a means to produce flexible and cheap solar cells. Tagging on to existing work already performed on germanium quantum dot solar cells, additional work was carried out to further characterize the material. The effect of film thickness, nano-particle surface conditions and thermal anneal were investigated. There is evidence to suggest that the quantum dot devices contain high levels of parasitic resistances. Short circuit current densities increase by up to two times with two spin-cast layers compared to four, leading to the conjecture that charge carrier life time is low with high levels of recombination. Annealing to improve carrier mobility produces devices with current densities up to 301microA, a fourfold increase, but output voltages saw a sharp decrease from 0.12V to 0.015V. In tandem with the work on germanium, experiments on silicon quantum dots were also carried out to investigate their viability for use as photovoltaic devices. The stronger bonds formed by silicon hindered the ligand exchange process. Schottky diodes were made via drop casting and displayed a clear photovoltaic effect albeit with very low current densities. Interestingly, an open circuit voltage was observed even when not under illumination and further investigations are ongoing.

Hot Carrier-Based Near-Field Thermophotovoltaic Energy Conversion.

PubMed

St-Gelais, Raphael; Bhatt, Gaurang Ravindra; Zhu, Linxiao; Fan, Shanhui; Lipson, Michal

2017-03-28

Near-field thermophotovoltaics (NFTPV) is a promising approach for direct conversion of heat to electrical power. This technology relies on the drastic enhancement of radiative heat transfer (compared to conventional blackbody radiation) that occurs when objects at different temperatures are brought to deep subwavelength distances (typically <100 nm) from each other. Achieving such radiative heat transfer between a hot object and a photovoltaic (PV) cell could allow direct conversion of heat to electricity with a greater efficiency than using current solid-state technologies (e.g., thermoelectric generators). One of the main challenges in the development of this technology, however, is its incompatibility with conventional silicon PV cells. Thermal radiation is weak at frequencies larger than the ∼1.1 eV bandgap of silicon, such that PV cells with lower excitation energies (typically 0.4-0.6 eV) are required for NFTPV. Using low bandgap III-V semiconductors to circumvent this limitation, as proposed in most theoretical works, is challenging and therefore has never been achieved experimentally. In this work, we show that hot carrier PV cells based on Schottky junctions between silicon and metallic films could provide an attractive solution for achieving high efficiency NFTPV electricity generation. Hot carrier science is currently an important field of research and several approaches are investigated for increasing the quantum efficiency (QE) of hot carrier generation beyond conventional Fowler model predictions. If the Fowler limit can indeed be overcome, we show that hot carrier-based NFTPV systems-after optimization of their thermal radiation spectrum-could allow electricity generation with up to 10-30% conversion efficiencies and 10-500 W/cm 2 generated power densities (at 900-1500 K temperatures). We also discuss how the unique properties of thermal radiation in the extreme near-field are especially well suited for investigating recently proposed approaches for high QE hot carrier junctions. We therefore expect our work to be of interest for the field of hot carrier science and-by relying solely on conventional thin film materials-to provide a path for the experimental demonstration of NFTPV energy conversion.

Comparison of Pyranometers and Reference Cells on Fixed and One-Axis Tracking Surfaces: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooraghi, Michael R; Sengupta, Manajit; Vignola, Frank

A wide variety of sensors are used to monitor the irradiance incident on solar modules to evaluate the performance of photovoltaic (PV) systems. These instruments range from secondary standard pyranometers to photodiode-based pyranometers to reference cells. Although instruments are mounted in the plane of array of the modules, a wide range of results have been obtained. Some of these difference have been assumed to come from systematic uncertainties associated with the irradiance sensors. This study is an attempt to quantify these differences by comparing the output of selected thermopile pyranometers to photodiode-based pyranometers and reference cells on a horizontal surface,more » a fixed-tilt surface, and a one-axis tracking surface. This analysis focuses on clear-sky results from two sites with different climatic conditions. Several important features were observed. Photodiode-based pyranometers and reference cells produce widely different results under clear skies, especially at larger angles of incidence, even though both instruments are based on measuring the short-circuit current of solar cells. The difference is caused by the scattering of light as it passes through the glazing of the reference cell or the diffuser lens of the photodioded-base pyranometer. Both instruments are shown to have similar response to the spectral distribution of the irradiance when compared to the thermopile-based pyranometer, which has a response nearly independent of the wavelength of light used by PV modules.« less

A miniature solar device for overall water splitting consisting of series-connected spherical silicon solar cells.

PubMed

Kageshima, Yosuke; Shinagawa, Tatsuya; Kuwata, Takaaki; Nakata, Josuke; Minegishi, Tsutomu; Takanabe, Kazuhiro; Domen, Kazunari

2016-04-18

A novel "photovoltaics (PV) + electrolyzer" concept is presented using a simple, small, and completely stand-alone non-biased device for solar-driven overall water splitting. Three or four spherical-shaped p-n junction silicon balls were successfully connected in series, named "SPHELAR." SPHELAR possessed small projected areas of 0.20 (3PVs) and 0.26 cm(2) (4PVs) and exhibited working voltages sufficient for water electrolysis. Impacts of the configuration on the PV module performance were carefully analyzed, revealing that a drastic increase in the photocurrent (≈20%) was attained by the effective utilization of a reflective sheet. Separate investigations on the electrocatalyst performance showed that non-noble metal based materials with reasonably small sizes (<0.80 cm(2)) exhibited substantial currents at the PV working voltage. By combining the observations of the PV characteristics, light management and electrocatalyst performance, solar-driven overall water splitting was readily achieved, reaching solar-to-hydrogen efficiencies of 7.4% (3PVs) and 6.4% (4PVs).

Comparative PV LCOE Calculator Documentation | Photovoltaic Research | NREL

Science.gov Websites

Comparative Photovoltaic (PV) Levelized Cost of Energy (LCOE) Calculator. Getting started This tool is and watch the LCOE values in the results section change immediately. Example: Cell cost reduction In the proposed section, drag the cell cost slider or type in the cell cost numeric input field to reduce

Hybrid Tandem Solar Cells | Photovoltaic Research | NREL

Science.gov Websites

Hybrid Tandem Solar Cells Hybrid Tandem Solar Cells To achieve aggressive cost reductions in photovoltaics (PV) beyond the 6¢/kWh SunShot Initiative 2020 goal, module efficiency must be increased beyond on a silicon platform and that aim to provide viable prototypes for commercialization. PV Research

New prospects for PV powered water desalination plants: case studies in Saudi Arabia: New prospects for PV powered water desalination plants

DOE PAGES

Fthenakis, Vasilis; Atia, Adam A.; Morin, Olivier; ...

2015-01-28

Increased water demand and increased drought episodes in the Middle East and other regions necessitate an expansion in desalination projects and create a great market opportunity for photovoltaics (PV). PV-powered desalination has previously been regarded as not being a cost-competitive solution when compared with conventionally powered desalination; however, the decline in PV costs over the last few years has changed this outlook. Here, this article presents up-to-date performance and cost analysis of reverse osmosis (RO) desalination powered with PV connected to the Saudi Arabian grid. Reference cases include relatively small (i.e., producing 6550 m 3 water per day) and largemore » (i.e., 190 000 m 3/day) desalination plants using seawater at a salinity of 40 000 ppm. We used data from a King Abdullah University for Science and Technology presentation and Hybrid Optimization Model for Electric Renewables 2.81 Energy Modeling Software (HOMER Energy LLC) in tandem with Desalination Economic Evaluation Program 4.0 (International Atomic Energy Agency) desalination software to analyze the techno-economic feasibility of these plants. The first phase of our work entailed a comparison between dual-axis high concentration PV (CPV) equipped with triple junction III/V solar cells and CdTe PV-powered RO systems. The estimated levelized cost of electricity from CPV is 0.16/kWh dollars, whereas that from CdTe PV is $0.10/kWh dollars and 0.09/kWh dollars for fixed-tilt and one-axis tracking systems, respectively. These costs are higher than the price of diesel-based grid electricity in the region because diesel fuel is heavily subsidized in Saudi Arabia.« less

Photovoltaic materials and devices 2016

DOE PAGES

Sopori, Bhushan; Basnyat, Prakash; Mehta, Vishal

2016-01-01

Photovoltaic energy continues to grow with about 59 GW of solar PV installed in 2015. While most of the PV production (about 93%) was Si wafer based, both CdTe and CI(G)S are growing in their shares. There is also continued progress at the laboratory scale in OPV and dye sensitized solar cells. As the market grows, emphasis on reducing the cost of modules and systems continues to grow. This is the fourth special issue of this journal that is dedicated to gathering selected papers on recent advances in materials, devices, and modules/PV systems. This issue contains sixteen papers on variousmore » aspects of photovoltaics. As a result, these fall in four broad categories of novel materials, device design and fabrication, modules, and systems.« less

Using the Spatial Distribution of Installers to Define Solar Photovoltaic Markets

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Shaughnessy, Eric; Nemet, Gregory F.; Darghouth, Naim

2016-09-01

Solar PV market research to date has largely relied on arbitrary jurisdictional boundaries, such as counties, to study solar PV market dynamics. This paper seeks to improve solar PV market research by developing a methodology to define solar PV markets. The methodology is based on the spatial distribution of solar PV installers. An algorithm is developed and applied to a rich dataset of solar PV installations to study the outcomes of the installer-based market definitions. The installer-based approach exhibits several desirable properties. Specifically, the higher market granularity of the installer-based approach will allow future PV market research to study themore » relationship between market dynamics and pricing with more precision.« less

One-power IC with MPPT design

NASA Astrophysics Data System (ADS)

Xu, Shengzhi; Chu, Ian; Zhao, Gengshen; Wang, Qingzhang

2008-03-01

When proceed photovoltaic power system design, engineer needs prepared model of PV cells to evaluate system response, capability performance, and stability, the DC model is not enough, but an accuracy AC model plays a big role. This paper talks first about the AC model of PV cells, and DC model is also introduced in simple. There is a PV controller example explaining the steps to do system simulation in this paper. Two equivalent circuit models are implemented with mixed-signal language verilog-a, one hardware language easy to use and having good speed and high accuracy. Both of two models include solar cell arrays, one buck switched mode DC-DC converter, and the maximum power point tracking algorithm. The difference between them is that Solar cell in one of two models is with ac small signal parameter, another is without. The simulation result is given in comparison. This paper's work shows that ac parameter plays large role in switch-mode PV power system, especially when the switch frequency is higher than 100kHz.

Photovoltaics Innovation Roadmap Request for Information Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

On June 28, 2017, the U.S. Department of Energy’s Solar Energy Technologies Office (SETO) released the Photovoltaics (PV) Innovation Roadmap Request for Information (RFI) for public response and comment. The RFI sought feedback from PV stakeholders, including research and commercial communities, about the most important research and development (R&D) pathways to improve PV cell and module technology to reach the SETO’s SunShot 2030 cost targets of $0.03/W for utility PV installations, $0.04/W for commercial scale installations, and $0.05/W for residential PV installations.

A Mouse Model for Conditional Secretion of Specific Single-Chain Antibodies Provides Genetic Evidence for Regulation of Cortical Plasticity by a Non-cell Autonomous Homeoprotein Transcription Factor.

PubMed

Bernard, Clémence; Vincent, Clémentine; Testa, Damien; Bertini, Eva; Ribot, Jérôme; Di Nardo, Ariel A; Volovitch, Michel; Prochiantz, Alain

2016-05-01

During postnatal life the cerebral cortex passes through critical periods of plasticity allowing its physiological adaptation to the environment. In the visual cortex, critical period onset and closure are influenced by the non-cell autonomous activity of the Otx2 homeoprotein transcription factor, which regulates the maturation of parvalbumin-expressing inhibitory interneurons (PV cells). In adult mice, the maintenance of a non-plastic adult state requires continuous Otx2 import by PV cells. An important source of extra-cortical Otx2 is the choroid plexus, which secretes Otx2 into the cerebrospinal fluid. Otx2 secretion and internalization requires two small peptidic domains that are part of the DNA-binding domain. Thus, mutating these "transfer" sequences also modifies cell autonomous transcription, precluding this approach to obtain a cell autonomous-only mouse. Here, we develop a mouse model with inducible secretion of an anti-Otx2 single-chain antibody to trap Otx2 in the extracellular milieu. Postnatal secretion of this single-chain antibody by PV cells delays PV maturation and reduces plasticity gene expression. Induced adult expression of this single-chain antibody in cerebrospinal fluid decreases Otx2 internalization by PV cells, strongly induces plasticity gene expression and reopens physiological plasticity. We provide the first mammalian genetic evidence for a signaling mechanism involving intercellular transfer of a homeoprotein transcription factor. Our single-chain antibody mouse model is a valid strategy for extracellular neutralization that could be applied to other homeoproteins and signaling molecules within and beyond the nervous system.

76 FR 55892 - Nationwide Limited Public Interest Waiver Under Section 1605 (Buy American) of the American...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-09

... following solar photo-voltaic (PV) equipment: (1) Domestically-manufactured modules containing foreign... inconsistent with the public interest for incidental and/or ancillary solar Photovoltaic (PV) equipment, when this equipment is utilized in solar installations containing domestically manufactured PV cells or...

Intravacuolar Membranes Regulate CD8 T Cell Recognition of Membrane-Bound Toxoplasma gondii Protective Antigen.

PubMed

Lopez, Jodie; Bittame, Amina; Massera, Céline; Vasseur, Virginie; Effantin, Grégory; Valat, Anne; Buaillon, Célia; Allart, Sophie; Fox, Barbara A; Rommereim, Leah M; Bzik, David J; Schoehn, Guy; Weissenhorn, Winfried; Dubremetz, Jean-François; Gagnon, Jean; Mercier, Corinne; Cesbron-Delauw, Marie-France; Blanchard, Nicolas

2015-12-15

Apicomplexa parasites such as Toxoplasma gondii target effectors to and across the boundary of their parasitophorous vacuole (PV), resulting in host cell subversion and potential presentation by MHC class I molecules for CD8 T cell recognition. The host-parasite interface comprises the PV limiting membrane and a highly curved, membranous intravacuolar network (IVN) of uncertain function. Here, using a cell-free minimal system, we dissect how membrane tubules are shaped by the parasite effectors GRA2 and GRA6. We show that membrane association regulates access of the GRA6 protective antigen to the MHC I pathway in infected cells. Although insertion of GRA6 in the PV membrane is key for immunogenicity, association of GRA6 with the IVN limits presentation and curtails GRA6-specific CD8 responses in mice. Thus, membrane deformations of the PV regulate access of antigens to the MHC class I pathway, and the IVN may play a role in immune modulation. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Development of Cu(In,Ga)Se2 Test Coupons for Potential Induced Degradation Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Contreras, Miguel A.; Hacke, Peter; Repins, Ingrid

We report on the design, fabrication and accelerated testing of fully encapsulated small area coupons (approximately 7.5cm x 7.5 cm) for the purpose of researching potential induced degradation in Cu(In, Ga)Se2 based PV modules. The fabrication of these coupons enables the study of the solar cells and the materials used in PV module manufacturing such as top and bottom glass covers of different composition (soda-lime glass, high temperature glass, alkaline-free glass, etc), plastic-based top covers, ethylene vinyl acetate and edge seal encapsulation materials. The coupons can also be used to emulate framed and frameless modules that utilize either monolithically interconnectedmore » modules or singular cell type of modules. The design of the coupons, their fabrication, the materials used and their testing for 1000 hours under 85 degrees C and 85% RH conditions are presented.« less

Defined tetra-allelic gene disruption of the 4-coumarate:coenzyme A ligase 1 (Pv4CL1) gene by CRISPR/Cas9 in switchgrass results in lignin reduction and improved sugar release.

PubMed

Park, Jong-Jin; Yoo, Chang Geun; Flanagan, Amy; Pu, Yunqiao; Debnath, Smriti; Ge, Yaxin; Ragauskas, Arthur J; Wang, Zeng-Yu

2017-01-01

The development of genome editing technologies offers new prospects in improving bioenergy crops like switchgrass ( Panicum virgatum ). Switchgrass is an outcrossing species with an allotetraploid genome (2 n  = 4 x  = 36), a complexity which forms an impediment to generating homozygous knock-out plants. Lignin, a major component of the plant cell wall and a contributor to cellulosic feedstock's recalcitrance to decomposition, stands as a barrier to efficient biofuel production by limiting enzyme access to cell wall polymers during the fermentation process. We developed a CRISPR/Cas9 genome editing system in switchgrass to target a key enzyme involved in the early steps of monolignol biosynthesis, 4-Coumarate:coenzyme A ligase (4CL). Three 4CL genes, Pv4CL1 , Pv4CL2, and Pv4CL3 , were identified in switchgrass. Expression analysis revealed that Pv4CL1 transcripts were more abundant in the stem than in the leaf, while Pv4CL2 transcripts were barely detectable and Pv4CL3 was mainly expressed in the leaf. Pv4CL1 was selected as the target for CRISPR/Cas9 editing because of its preferential expression in highly lignified stem tissues. Specific guide RNA was constructed to target Pv4CL1 . After introducing the construct into switchgrass calli, 39 transgenic plants were regenerated. Using two rounds of PCR screening and sequencing, four plants were confirmed to have tetra-allelic mutations simultaneously. The Pv4CL1 knock-out plants had reduced cell wall thickness, an 8-30% reduction in total lignin content, a 7-11% increase in glucose release, and a 23-32% increase in xylose release. This study established a successful CRISPR/Cas9 system in switchgrass with mutation efficiency reaching 10%. The system allows the precise targeting of the selected Pv4CL1 gene to create switchgrass knock-out mutant plants with decreased lignin content and reduced recalcitrance.

Editorial: Photovoltaic Materials and Devices 2014

DOE PAGES

Sopori, Bhushan; Rupnowski, Peter; Shet, Sudhakar; ...

2014-12-22

An ever increasing demand on energy has fostered many new generation technologies, which include photovoltaics. In recent years, photovoltaic industry has grown very rapidly. The installed capacity of PV for 2013 was about 37 GW and 2014 sales are expected to be around 45 GW. However, there has been excess production for last several years, which is responsible in part for the low prices (about 60 c/W). To lower the PV energy costs further, a major strategy appears to be going to high efficiency solar cells. This approach is favored (over lower cost/lower efficiency) because cell efficiency has a verymore » large influence on the acceptable manufacturing cost of a PV module. Hence, the PV industry is moving toward developing processes and equipment to manufacture solar cells that can yield efficiencies >20%. Therefore, further research is needed within existing technologies to accomplish these objectives. Likewise, research will continue to seek new materials and devices.« less

Uniform sunlight concentration reflectors for photovoltaic cells.

PubMed

Rabady, Rabi Ibrahim

2014-03-20

Sunlight concentration is essential to reach high temperatures of a working fluid in solar-thermal applications and to reduce the cost of photovoltaic (PV) electricity generation systems. Commonly, sunlight concentration is realized by parabolic or cylindrical reflectors, which do not provide uniform concentration on the receiver finite surface. Uniform concentration of sunlight is favored especially for the PV conversion applications since it not only enhances the conversion efficiency of sunlight but also reduces the thermal variations along the receiving PV cell, which can be a performance and life-span limiting factor. In this paper a reflector profile that uniformly infiltrates the concentrated sunlight into the receiving unit is attempted. The new design accounts for all factors that contribute to the nonuniform concentration, like the reflector curvature, which spatially reflects the sunlight nonuniformly, and the angular dependency of both the reflector reflectivity and the sunlight transmission through the PV cell.

Hybrid micro-scale photovoltaics for enhanced energy conversion across all irradiation conditions

NASA Astrophysics Data System (ADS)

Agrawal, Gautam

A novel hybrid photovoltaics (HPV) architecture is presented that integrates high-performance micro-optics-based concentrator photovoltaics (CPV) array technology with a 1-sun photovoltaic (PV) cell within a low-profile panel structure. The approach simultaneously captures the direct solar radiation components with arrayed high-efficiency CPV cells and the diffuse solar components with an underlying wide-area PV cell. Performance analyses predict that the hybrid approach will significantly enhance the average energy produced per unit area for the full range of diffuse/direct radiation patterns across the USA. Furthermore, cost analyses indicate that the hybrid concept may be financially attractive for a wide range of locations. Indoor and outdoor experimental evaluation of a micro-optical system designed for use in a hybrid architecture verified that a large proportion of the direct radiation component was concentrated onto emulated micro-cell regions while most of the diffuse radiation and the remaining direct radiation was collected in the 1-sun cell area.

Determination of plasma volume in anaesthetized piglets using the carbon monoxide (CO) method.

PubMed

Heltne, J K; Farstad, M; Lund, T; Koller, M E; Matre, K; Rynning, S E; Husby, P

2002-07-01

Based on measurements of the circulating red blood cell volume (V(RBC)) in seven anaesthetized piglets using carbon monoxide (CO) as a label, plasma volume (PV) was calculated for each animal. The increase in carboxyhaemoglobin (COHb) concentration following administration of a known amount of CO into a closed circuit re-breathing system was determined by diode-array spectrophotometry. Simultaneously measured haematocrit (HCT) and haemoglobin (Hb) values were used for PV calculation. The PV values were compared with simultaneously measured PVs determined using the Evans blue technique. Mean values (SD) for PV were 1708.6 (287.3)ml and 1738.7 (412.4)ml with the CO method and the Evans blue technique, respectively. Comparison of PVs determined with the two techniques demonstrated good correlation (r = 0.995). The mean difference between PV measurements was -29.9 ml and the limits of agreement (mean difference +/-2SD) were -289.1 ml and 229.3 ml. In conclusion, the CO method can be applied easily under general anaesthesia and controlled ventilation with a simple administration system. The agreement between the compared methods was satisfactory. Plasma volume determined with the CO method is safe, accurate and has no signs of major side effects.

Materials and Chemical Science and Technology | Research | NREL

Science.gov Websites

Applications and Performance Developing high-efficiency crystalline PV, measuring PV cell/module performance Cells and Hydrogen Program Developing, integrating, and demonstrating hydrogen production/delivery /storage through core programs and EFRCs Point of Contact Bill Tumas MCST Research Advisors/Fellows Senior

Modern Topics in Energy and Power Technical Meeting

DTIC Science & Technology

2016-09-01

systems are abysmally low, primarily due to their poor electronic structure. The III-V-based solar cells show the highest solar PV efficiency and thus are...initiatives include creating jet fuel based on seawater, research on photovoltaics ( PVs ) of different types, lightweight fuel cell systems for unmanned air...technoeconomic analysis studies indicate that a 20% solar -to-hydrogen PEC conversion efficiency is necessary for a commercially viable system. Additional

Pathology, Organ Distribution, and Immune Response after Single and Repeated Intravenous Injection of Rats with Clinical-Grade Parvovirus H1

PubMed Central

Geletneky, Karsten; Leoni, Anne-Laure; Pohlmeyer-Esch, Gabriele; Loebhard, Stephanie; Baetz, Andrea; Leuchs, Barbara; Roscher, Mandy; Hoefer, Constance; Jochims, Karin; Dahm, Michael; Huber, Bernard; Rommelaere, Jean; Krebs, Ottheinz; Hajda, Jacek

2015-01-01

Parvovirus H1 (H1PV) is an autonomous parvovirus that is transmitted in rodent populations. Its natural host is rats. H1PV infection is nonpathogenic except in rat and hamster fetuses and newborns. H1PV infection of human cancer cells caused strong oncolytic effects in preclinical models. For a clinical trial of H1PV in patients with brain tumors, clinical-grade H1PV was produced according to Good Manufacturing Practices. This report focuses on results obtained after a single high-dose intravenous injection of highly purified H1PV in 30 rats and multiple (n = 17) intravenous injections at 3 dose levels in 223 rats. In both studies, no virus-related mortality or macroscopic organ changes related to H1PV occurred. Histopathology after multiple virus injections revealed minimal diffuse bile duct hyperplasia in livers of animals of the highest dose group and germinal center development in spleens of animals from the high-dose group. Liver changes were reversible within a 2-wk recovery period after the last injection. Hematology, blood chemistry, and coagulation analyses did not reveal significant toxicologic changes due to H1PV. Virus injection stimulated the production of IgG antibodies but did not alter mononuclear cell function or induce cytokine release. PCR analysis showed dose-dependent levels of viral genomes in all organs tested. The virus was excreted primarily through feces. These data provide important information regarding H1PV infection in its natural host. Due to the confirmation of the favorable safety profile of H1PV in a permissive animal model, a phase I/IIa clinical trial of H1PV in brain tumor patients could be initiated. PMID:25730754

From cells to laminate: probing and modeling residual stress evolution in thin silicon photovoltaic modules using synchrotron X-ray micro-diffraction experiments and finite element simulations

DOE PAGES

Tippabhotla, Sasi Kumar; Radchenko, Ihor; Song, W. J. R.; ...

2017-04-12

Fracture of silicon crystalline solar cells has recently been observed in increasing percentages especially in solar photovoltaic (PV) modules involving thinner silicon solar cells (<200 μm). Many failures due to fracture have been reported from the field because of environmental loading (snow, wind, etc.) as well as mishandling of the solar PV modules (during installation, maintenance, etc.). However, a significantly higher number of failures have also been reported during module encapsulation (lamination) indicating high residual stress in the modules and thus more prone to cell cracking. Here in this paper we report through the use of synchrotron X-ray submicron diffractionmore » coupled with physics-based finite element modeling, the complete residual stress evolution in mono-crystalline silicon solar cells during PV module integration process. For the first time, we unravel the reason for the high stress and cracking of silicon cells near soldered inter-connects. Our experiments revealed a significant increase of residual stress in the silicon cell near the solder joint after lamination. Moreover, our finite element simulations show that this increase of stress during lamination is a result of highly localized bending of the cell near the soldered inter-connects. Further, the synchrotron X-ray submicron diffraction has proven to be a very effective way to quantitatively probe mechanical stress in encapsulated silicon solar cells. Thus, this technique has ultimately enabled these findings leading to the enlightening of the role of soldering and encapsulation processes on the cell residual stress. This model can be further used to suggest methodologies that could lead to lower stress in encapsulated silicon solar cells, which are the subjects of our continued investigations.« less

From cells to laminate: probing and modeling residual stress evolution in thin silicon photovoltaic modules using synchrotron X-ray micro-diffraction experiments and finite element simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tippabhotla, Sasi Kumar; Radchenko, Ihor; Song, W. J. R.

Fracture of silicon crystalline solar cells has recently been observed in increasing percentages especially in solar photovoltaic (PV) modules involving thinner silicon solar cells (<200 μm). Many failures due to fracture have been reported from the field because of environmental loading (snow, wind, etc.) as well as mishandling of the solar PV modules (during installation, maintenance, etc.). However, a significantly higher number of failures have also been reported during module encapsulation (lamination) indicating high residual stress in the modules and thus more prone to cell cracking. Here in this paper we report through the use of synchrotron X-ray submicron diffractionmore » coupled with physics-based finite element modeling, the complete residual stress evolution in mono-crystalline silicon solar cells during PV module integration process. For the first time, we unravel the reason for the high stress and cracking of silicon cells near soldered inter-connects. Our experiments revealed a significant increase of residual stress in the silicon cell near the solder joint after lamination. Moreover, our finite element simulations show that this increase of stress during lamination is a result of highly localized bending of the cell near the soldered inter-connects. Further, the synchrotron X-ray submicron diffraction has proven to be a very effective way to quantitatively probe mechanical stress in encapsulated silicon solar cells. Thus, this technique has ultimately enabled these findings leading to the enlightening of the role of soldering and encapsulation processes on the cell residual stress. This model can be further used to suggest methodologies that could lead to lower stress in encapsulated silicon solar cells, which are the subjects of our continued investigations.« less

Paint it Black: One-Step Etch Cuts Solar Cell Costs - Continuum Magazine

Science.gov Websites

quicker, cheaper way to produce large volumes of high-performance PV devices. Cost is a major obstacle for propel PV toward cost-competitiveness. A New Approach to Antireflection Any light reflected from a solar etching large pyramids into the cell surface, add considerable cost to a solar cell-and they succeed only

Three-dimensional carbon nanotube based photovoltaics

NASA Astrophysics Data System (ADS)

Flicker, Jack

2011-12-01

Photovoltaic (PV) cells with a three dimensional (3D) morphology are an exciting new research thrust with promise to create cheaper, more efficient solar cells. This work introduces a new type of 3D PV device based on carbon nanotube (CNT) arrays. These arrays are paired with the thin film heterojunction, CdTe/CdS, to form a complete 3D carbon nanotube PV device (3DCNTPV). Marriage of a complicated 3D structure with production methods traditionally used for planar CdTe solar cell is challenging. This work examines the problems associated with processing these types of cells and systematically alters production methods of the semiconductor layers and electrodes to increase the short circuit current (Isc), eliminate parasitic shunts, and increase the open circuit voltage (Voc). The main benefit of 3D solar cell is the ability to utilize multiple photon interactions with the solar cell surface. The three dimensionality allows photons to interact multiple times with the photoactive material, which increases the absorption and the overall power output over what is possible with a two dimensional (2D) morphology. To quantify the increased power output arising from these multiple photon interactions, a new absorption efficiency term, eta3D, is introduced. The theoretical basis behind this new term and how it relates to the absorption efficiency of a planar cell, eta 2D, is derived. A unique model for the average number of multiple photon impingements, Gamma, is proposed based on three categories of 3D morphology: an infinite trench, an enclosed box, and an array of towers. The derivation of eta3D and Gamma for these 3D PV devices gives a complete picture of the enhanced power output over 2D cells based on CNT array height, pitch, radius, and shape. This theory is validated by monte carlo simulations and experiment. This new type of 3D PV devices has been shown to work experimentally. The first 3DCNTPV cells created posses Isc values of 0.085 to 17.872mA/cm2 and Voc values in the range of 2 to 122mV. These figures of merit are low for CdTe cells, so planar cells without CNTs and planar cells with unpatterned CNTs were developed. The planar cells had figures of merit about the same as the 3DCNTPV cells, indicating that the low efficiency of the 3DCNTPV cell is due to processing and not inherent to the 3D structure. CNTs were successfully grown directly on an Ag underlayer, but the growth reproducibility and the CNT height was not sufficient for use in 3DCNTPV devices. Therefore, CNTs were grown on a SiO2 passivated Si wafer and then metallized. This eliminated the CNTs as the back contact and used them only as a structure to provide the 3D morphology. These cells exhibited low shunt resistances on the order of 300O, causing a straight line IV curve. This shunting was found to be caused by the ion assisted deposition of ITO. This plasma process etched away semiconducting layers and caused pinholes in the CdTe/CdS film. Many different strategies were utilized to try and eliminate this shunt and induce curvature in the IV curve, including adding sacrificial metal layers before the ITO deposition, using electron beam evaporated ITO, and using RF sputtered ITO. The addition of metal layers before ITO deposition did not result in cells which could reliably demonstrate both photocurrent and IV curvature. Electron beam deposition of ITO resulted in cells with excellent IV curvature, but the ITO deposited in this manner was too resistive and absorptive to create well functioning cells. The output power of the cells at varying incident angles of light was measured. The cells show an increase in the normalized power output compared to similar planar cells when the solar ux is at off-normal angles. The power output vs. incident angle curve takes an inverted C-type curve as predicted by the theory developed here. The complete theory of 3DCNTPV presented in this work describes the power output vs. incident angle of a 3DCNTPV cell based only on cell morphology. The experimental power output vs. zenith angle was compared to the theoretically calculated power output with very good agreement between the two. (Abstract shortened by UMI.)

Genetic variability and natural selection at the ligand domain of the Duffy binding protein in brazilian Plasmodium vivax populations

PubMed Central

2010-01-01

Background Plasmodium vivax malaria is a major public health challenge in Latin America, Asia and Oceania, with 130-435 million clinical cases per year worldwide. Invasion of host blood cells by P. vivax mainly depends on a type I membrane protein called Duffy binding protein (PvDBP). The erythrocyte-binding motif of PvDBP is a 170 amino-acid stretch located in its cysteine-rich region II (PvDBPII), which is the most variable segment of the protein. Methods To test whether diversifying natural selection has shaped the nucleotide diversity of PvDBPII in Brazilian populations, this region was sequenced in 122 isolates from six different geographic areas. A Bayesian method was applied to test for the action of natural selection under a population genetic model that incorporates recombination. The analysis was integrated with a structural model of PvDBPII, and T- and B-cell epitopes were localized on the 3-D structure. Results The results suggest that: (i) recombination plays an important role in determining the haplotype structure of PvDBPII, and (ii) PvDBPII appears to contain neutrally evolving codons as well as codons evolving under natural selection. Diversifying selection preferentially acts on sites identified as epitopes, particularly on amino acid residues 417, 419, and 424, which show strong linkage disequilibrium. Conclusions This study shows that some polymorphisms of PvDBPII are present near the erythrocyte-binding domain and might serve to elude antibodies that inhibit cell invasion. Therefore, these polymorphisms should be taken into account when designing vaccines aimed at eliciting antibodies to inhibit erythrocyte invasion. PMID:21092207

A simplified solar cell array modelling program

NASA Technical Reports Server (NTRS)

Hughes, R. D.

1982-01-01

As part of the energy conversion/self sufficiency efforts of DSN engineering, it was necessary to have a simplified computer model of a solar photovoltaic (PV) system. This article describes the analysis and simplifications employed in the development of a PV cell array computer model. The analysis of the incident solar radiation, steady state cell temperature and the current-voltage characteristics of a cell array are discussed. A sample cell array was modelled and the results are presented.

Science and Technology Facility | Photovoltaic Research | NREL

Science.gov Websites

- and back-contact schemes for advanced thin-film PV solar cells. Contact materials include metals Science and Technology Facility Science and Technology Facility Solar cell, thin-film, and Development Laboratory Research in thin-film PV is accomplished in this lab with techniques used for

Control strategy of grid-connected photovoltaic generation system based on GMPPT method

NASA Astrophysics Data System (ADS)

Wang, Zhongfeng; Zhang, Xuyang; Hu, Bo; Liu, Jun; Li, Ligang; Gu, Yongqiang; Zhou, Bowen

2018-02-01

There are multiple local maximum power points when photovoltaic (PV) array runs under partial shading condition (PSC).However, the traditional maximum power point tracking (MPPT) algorithm might be easily trapped in local maximum power points (MPPs) and cannot find the global maximum power point (GMPP). To solve such problem, a global maximum power point tracking method (GMPPT) is improved, combined with traditional MPPT method and particle swarm optimization (PSO) algorithm. Under different operating conditions of PV cells, different tracking algorithms are used. When the environment changes, the improved PSO algorithm is adopted to realize the global optimal search, and the variable step incremental conductance (INC) method is adopted to achieve MPPT in optimal local location. Based on the simulation model of the PV grid system built in Matlab/Simulink, comparative analysis of the tracking effect of MPPT by the proposed control algorithm and the traditional MPPT method under the uniform solar condition and PSC, validate the correctness, feasibility and effectiveness of the proposed control strategy.

You're a What? Solar Photovoltaic Installer

ERIC Educational Resources Information Center

Torpey, Elka Maria

2009-01-01

This article talks about solar photovoltaic (PV) installer and features Rebekah Hren, a solar PV installer who puts solar panels on roofs and in other sunny places to turn the sun's power into electricity. Hren enjoys promoting renewable energy, in part because it's an emerging field. In solar PV systems, solar cells--devices that convert sunlight…

Identification of a Functional Risk Variant for Pemphigus Vulgaris in the ST18 Gene

PubMed Central

Vodo, Dan; Sarig, Ofer; Ben-Asher, Edna; Olender, Tsviya; Bochner, Ron; Goldberg, Ilan; Nosgorodsky, Judith; Alkelai, Anna; Tatarskyy, Pavel; Peled, Alon; Baum, Sharon; Barzilai, Aviv; Ibrahim, Saleh M.; Zillikens, Detlef; Lancet, Doron; Sprecher, Eli

2016-01-01

Pemphigus vulgaris (PV) is a life-threatening autoimmune mucocutaneous blistering disease caused by disruption of intercellular adhesion due to auto-antibodies directed against epithelial components. Treatment is limited to immunosuppressive agents, which are associated with serious adverse effects. The propensity to develop the disease is in part genetically determined. We therefore reasoned that the delineation of PV genetic basis may point to novel therapeutic strategies. Using a genome-wide association approach, we recently found that genetic variants in the vicinity of the ST18 gene confer a significant risk for the disease. Here, using targeted deep sequencing, we identified a PV-associated variant residing within the ST18 promoter region (p<0.0002; odds ratio = 2.03). This variant was found to drive increased gene transcription in a p53/p63-dependent manner, which may explain the fact that ST18 is up-regulated in the skin of PV patients. We then discovered that when overexpressed, ST18 stimulates PV serum-induced secretion of key inflammatory molecules and contributes to PV serum-induced disruption of keratinocyte cell-cell adhesion, two processes previously implicated in the pathogenesis of PV. Thus, the present findings indicate that ST18 may play a direct role in PV and consequently represents a potential target for the treatment of this disease. PMID:27148741

Determining the Effects of Environment and Atmospheric Parameters on PV Field Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Micheli, Leonardo; Muller, Matthew; Kurtz, Sarah

2016-11-21

The performance losses due to soiling occurring on any photovoltaic (PV) device are caused by a complex mechanism that involves numerous factors and their interactions. For this reason, the present work analyzes the outputs of reference PV cells installed in various locations, with the aim of contributing to the identification of the most important factors influencing the accumulation of dust on a PV surface. Parameters such as the air-quality indexes, the recurrence and the amount of rainfall and the climate zone are investigated and related to the soiling losses of the PV device.

Immunotherapeutic Potential of Oncolytic H-1 Parvovirus: Hints of Glioblastoma Microenvironment Conversion towards Immunogenicity.

PubMed

Angelova, Assia L; Barf, Milena; Geletneky, Karsten; Unterberg, Andreas; Rommelaere, Jean

2017-12-15

Glioblastoma, one of the most aggressive primary brain tumors, is characterized by highly immunosuppressive microenvironment. This contributes to glioblastoma resistance to standard treatment modalities and allows tumor growth and recurrence. Several immune-targeted approaches have been recently developed and are currently under preclinical and clinical investigation. Oncolytic viruses, including the autonomous protoparvovirus H-1 (H-1PV), show great promise as novel immunotherapeutic tools. In a first phase I/IIa clinical trial (ParvOryx01), H-1PV was safe and well tolerated when locally or systemically administered to recurrent glioblastoma patients. The virus was able to cross the blood-brain (tumor) barrier after intravenous infusion. Importantly, H-1PV treatment of glioblastoma patients was associated with immunogenic changes in the tumor microenvironment. Tumor infiltration with activated cytotoxic T cells, induction of cathepsin B and inducible nitric oxide (NO) synthase (iNOS) expression in tumor-associated microglia/macrophages (TAM), and accumulation of activated TAM in cluster of differentiation (CD) 40 ligand (CD40L)-positive glioblastoma regions was detected. These are the first-in-human observations of H-1PV capacity to switch the immunosuppressed tumor microenvironment towards immunogenicity. Based on this pilot study, we present a tentative model of H-1PV-mediated modulation of glioblastoma microenvironment and propose a combinatorial therapeutic approach taking advantage of H-1PV-induced microglia/macrophage activation for further (pre)clinical testing.

Solar and Thermal Energy Harvesting Textile Composites for Aerospace Applications

DTIC Science & Technology

2012-06-01

approaches to tuning the sensitivity bands of photodetectors, and improving light in-coupling in solar cells and pho- todetectors. Encouraged by these...PV) cells . Using this framework, we have designed and realized solar cell structures that do not use indium-tin oxide, a brittle and expensive...ceramic that is typically used as a transparent electrode in or- ganic solar cells . This achievement is important for integration of PV functionality in

Solution-Processed Small-Molecule Bulk Heterojunctions: Leakage Currents and the Dewetting Issue for Inverted Solar Cells.

PubMed

Destouesse, Elodie; Chambon, Sylvain; Courtel, Stéphanie; Hirsch, Lionel; Wantz, Guillaume

2015-11-11

In organic photovoltaic (PV) devices based on solution-processed small molecules, we report here that the physicochemical properties of the substrate are critical for achieving high-performances organic solar cells. Three different substrates were tested: ITO coated with PSS, ZnO sol-gel, and ZnO nanoparticles. PV performances are found to be low when the ZnO nanoparticles layer is used. This performance loss is attributed to the formation of many dewetting points in the active layer, because of a relatively high roughness of the ZnO nanoparticles layer, compared to the other layers. We successfully circumvented this phenomenon by adding a small quantity of polystyrene (PS) in the active layer. The introduction of PS improves the quality of film forming and reduces the dark currents of solar cells. Using this method, high-efficiency devices were achieved, even in the case of substrates with higher roughness.

Perovskite Solar Cell Stability Workshop: Quick Look Report

DTIC Science & Technology

2016-08-12

Commercialization of Perovskite PV – Markets, Concerns, Opportunities” by Dirk Weiss, First Solar , USA j. “Expectations for PV Product Testing Today” by Sarah...Perovskite Solar Cell Stability Workshop Quick-Look Report Held by the Office of Naval Research at University...Workshop Summary, 11-12 Aug 2016 4. TITLE AND SUBTITLE Perovskite Solar Cell Stability Workshop: Quick-Look Report 5. FUNDING NUMBERS 6. AUTHOR(S

From photoluminescence to thermal emission: Thermally-enhanced PL (TEPL) for efficient PV (Conference Presentation)

NASA Astrophysics Data System (ADS)

Manor, Assaf; Kruger, Nimrod; Martin, Leopoldo L.; Rotschild, Carmel

2016-09-01

The Shockley-Queisser efficiency limit of 40% for single-junction photovoltaic (PV) cells is mainly caused by the heat dissipation accompanying the process of electro-chemical potential generation. Concepts such as solar thermo-photovoltaics (STPV) aim to harvest this heat loss by the use of a primary absorber which acts as a mediator between the sun and the PV, spectrally shaping the light impinging on the cell. However, this approach is challenging to realize due to the high operating temperatures of above 2000K required in order to generate high thermal emission fluxes. After over thirty years of STPV research, the record conversion efficiency for STPV device stands at 3.2% for 1285K operating temperature. In contrast, we recently demonstrated how thermally-enhanced photoluminescence (TEPL) is an optical heat-pump, in which photoluminescence is thermally blue-shifted upon heating while the number of emitted photons is conserved. This process generates energetic photon-rates which are comparable to thermal emission in significantly reduced temperatures, opening the way for a TEPL based energy converter. In such a device, a photoluminescent low bandgap absorber replaces the STPV thermal absorber. The thermalization heat induces a temperature rise and a blue-shifted emission, which is efficiently harvested by a higher bandgap PV. We show that such an approach can yield ideal efficiencies of 70% at 1140K, and realistic efficiencies of almost 50% at moderate concentration levels. As an experimental proof-of-concept, we demonstrate 1.4% efficient TEPL energy conversion of an Nd3+ system coupled to a GaAs cell, at 600K.

Modelling a reliable wind/PV/storage power system for remote radio base station sites without utility power

NASA Astrophysics Data System (ADS)

Bitterlin, Ian F.

The development of photovoltaic (PV) cells has made steady progress from the early days, when only the USA space program could afford to deploy them, to now, seeing them applied to roadside applications even in our Northern European climes. The manufacturing cost per watt has fallen and the daylight-to-power conversion efficiency increased. At the same time, the perception that the sun has to be directly shining on it for a PV array to work has faded. On some of those roadside applications, particularly for remote emergency telephones or for temporary roadwork signage where a utility electrical power connection is not practical, the keen observer will spot, usually in addition to a PV array, a small wind-turbine and an electrical cabinet quite obviously (by virtue of its volume) containing a storage battery. In the UK, we have the lions share (>40%) of Europe's entire wind power resource although, despite press coverage of the "anti-wind" lobby to the contrary, we have hardly started to harvest this clean and free energy source. Taking this (established and proven) roadside solution one step further, we will consider higher power applications. A cellular phone system is one where a multitude of remote radio base stations (RBS) are required to provide geographical coverage. With networks developing into the so called "3G" technologies the need for base stations has tripled, as each 3G cell covers only 1/3 the geographical area of its "2G" counterpart. To cover >90% of the UK's topology (>97% population coverage) with 3G cellular technology will requires in excess of 12,000 radio base stations per operator network. In 2001, there were around 25,000 established sites and, with an anticipated degree of collocation by necessity, that figure is forecast to rise to >47,000. Of course, the vast majority of these sites have a convenient grid connection. However, it is easy to see that the combination of wind and PV power generation and an energy storage system may be an interesting solution for the more rural and remote applications - particularly those where an electrical supply is not available or practical - and this paper attempts to explore the current practicalities of such a power generation solution for those cellular phone base stations.

Prostate health index (PHI) and prostate-specific antigen (PSA) predictive models for prostate cancer in the Chinese population and the role of digital rectal examination-estimated prostate volume.

PubMed

Chiu, Peter K F; Roobol, Monique J; Teoh, Jeremy Y; Lee, Wai-Man; Yip, Siu-Ying; Hou, See-Ming; Bangma, Chris H; Ng, Chi-Fai

2016-10-01

To investigate PSA- and PHI (prostate health index)-based models for prediction of prostate cancer (PCa) and the feasibility of using DRE-estimated prostate volume (DRE-PV) in the models. This study included 569 Chinese men with PSA 4-10 ng/mL and non-suspicious DRE with transrectal ultrasound (TRUS) 10-core prostate biopsies performed between April 2008 and July 2015. DRE-PV was estimated using 3 pre-defined classes: 25, 40, or 60 ml. The performance of PSA-based and PHI-based predictive models including age, DRE-PV, and TRUS prostate volume (TRUS-PV) was analyzed using logistic regression and area under the receiver operating curves (AUC), in both the whole cohort and the screening age group of 55-75. PCa and high-grade PCa (HGPCa) was diagnosed in 10.9 % (62/569) and 2.8 % (16/569) men, respectively. The performance of DRE-PV-based models was similar to TRUS-PV-based models. In the age group 55-75, the AUCs for PCa of PSA alone, PSA with DRE-PV and age, PHI alone, PHI with DRE-PV and age, and PHI with TRUS-PV and age were 0.54, 0.71, 0.76, 0.78, and 0.78, respectively. The corresponding AUCs for HGPCa were higher (0.60, 0.70, 0.85, 0.83, and 0.83). At 10 and 20 % risk threshold for PCa, 38.4 and 55.4 % biopsies could be avoided in the PHI-based model, respectively. PHI had better performance over PSA-based models and could reduce unnecessary biopsies. A DRE-assessed PV can replace TRUS-assessed PV in multivariate prediction models to facilitate clinical use.

Nonhomologous Recombination between Defective Poliovirus and Coxsackievirus Genomes Suggests a New Model of Genetic Plasticity for Picornaviruses

PubMed Central

Holmblat, Barbara; Jégouic, Sophie; Muslin, Claire; Blondel, Bruno; Joffret, Marie-Line

2014-01-01

ABSTRACT Most of the circulating vaccine-derived polioviruses (cVDPVs) implicated in poliomyelitis outbreaks in Madagascar have been shown to be recombinants between the type 2 poliovirus (PV) strain of the oral polio vaccine (Sabin 2) and another species C human enterovirus (HEV-C), such as type 17 coxsackie A virus (CA17) in particular. We studied intertypic genetic exchanges between PV and non-PV HEV-C by developing a recombination model, making it possible to rescue defective type 2 PV RNA genomes with a short deletion at the 3′ end by the cotransfection of cells with defective or infectious CA17 RNAs. We isolated over 200 different PV/CA17 recombinants, using murine cells expressing the human PV receptor (PVR) and selecting viruses with PV capsids. We found some homologous (H) recombinants and, mostly, nonhomologous (NH) recombinants presenting duplications of parental sequences preferentially located in the regions encoding proteins 2A, 2B, and 3A. Short duplications appeared to be stable, whereas longer duplications were excised during passaging in cultured cells or after multiplication in PVR-transgenic mice, generating H recombinants with diverse sites of recombination. This suggests that NH recombination events may be a transient, intermediate step in the generation and selection of the fittest H recombinants. In addition to the classical copy-choice mechanism of recombination thought to generate mostly H recombinants, there may also be a modular mechanism of recombination, involving NH recombinant precursors, shaping the genomes of recombinant enteroviruses and other picornaviruses. PMID:25096874

Interplay of oxygen-evolution kinetics and photovoltaic power curves on the construction of artificial leaves

PubMed Central

Surendranath, Yogesh; Bediako, D. Kwabena; Nocera, Daniel G.

2012-01-01

An artificial leaf can perform direct solar-to-fuels conversion. The construction of an efficient artificial leaf or other photovoltaic (PV)-photoelectrochemical device requires that the power curve of the PV material and load curve of water splitting, composed of the catalyst Tafel behavior and cell resistances, be well-matched near the thermodynamic potential for water splitting. For such a condition, we show here that the current density-voltage characteristic of the catalyst is a key determinant of the solar-to-fuels efficiency (SFE). Oxidic Co and Ni borate (Co-Bi and Ni-Bi) thin films electrodeposited from solution yield oxygen-evolving catalysts with Tafel slopes of 52 mV/decade and 30 mV/decade, respectively. The consequence of the disparate Tafel behavior on the SFE is modeled using the idealized behavior of a triple-junction Si PV cell. For PV cells exhibiting similar solar power-conversion efficiencies, those displaying low open circuit voltages are better matched to catalysts with low Tafel slopes and high exchange current densities. In contrast, PV cells possessing high open circuit voltages are largely insensitive to the catalyst’s current density-voltage characteristics but sacrifice overall SFE because of less efficient utilization of the solar spectrum. The analysis presented herein highlights the importance of matching the electrochemical load of water-splitting to the onset of maximum current of the PV component, drawing a clear link between the kinetic profile of the water-splitting catalyst and the SFE efficiency of devices such as the artificial leaf. PMID:22689962

A photovoltaic-driven and energy-autonomous CMOS implantable sensor.

PubMed

Ayazian, Sahar; Akhavan, Vahid A; Soenen, Eric; Hassibi, Arjang

2012-08-01

An energy-autonomous, photovoltaic (PV)-driven and MRI-compatible CMOS implantable sensor is presented. On-chip P+/N-well diode arrays are used as CMOS-compatible PV cells to harvest μW's of power from the light that penetrates into the tissue. In this 2.5 mm × 2.5 mm sub-μW integrated system, the in-vivo physiological signals are first measured by using a subthreshold ring oscillator-based sensor, the acquired data is then modulated into a frequency-shift keying (FSK) signal, and finally transmitted neuromorphically to the skin surface by using a pair of polarized electrodes.

Analysis of Thermal Losses for a Variety of Single-Junction Photovoltaic Cells: An Interesting Means of Thermoelectric Heat Recovery

NASA Astrophysics Data System (ADS)

Lorenzi, Bruno; Acciarri, Maurizio; Narducci, Dario

2015-06-01

Exploitation of solar energy conversion has become a fundamental aspect of satisfying a growing demand for energy. Thus, improvement of the efficiency of conversion in photovoltaic (PV) devices is highly desirable to further promote this source. Because it is well known that the most relevant efficiency constraint, especially for single-junction solar cells, is unused heat within the device, hybrid thermo-photovoltaic systems seem promising . Among several hybrid solutions proposed in the literature, coupling of thermoelectric and PV devices seems one of the most interesting. Taking full advantage of this technology requires proper definition and analysis of the thermal losses occurring in PV cells. In this communication we propose a novel analysis of such losses, decoupling source-dependent and absorber-dependent losses. This analysis enables an evaluation of the actual recoverable amount of energy, depending on the absorber used in the PV cell. It shows that for incoming solar irradiation of , and depending on the choice of material, the maximum available thermal power ranges from (for single-crystal silicon) to (for amorphous silicon).

Direct electrochemistry of Shewanella loihica PV-4 on gold nanoparticles-modified boron-doped diamond electrodes fabricated by layer-by-layer technique.

PubMed

Wu, Wenguo; Xie, Ronggang; Bai, Linling; Tang, Zuming; Gu, Zhongze

2012-05-01

Microbial Fuel Cells (MFCs) are robust devices capable of taping biological energy, converting pollutants into electricity through renewable biomass. The fabrication of nanostructured electrodes with good bio- and electrochemical activity, play a profound role in promoting power generation of MFCs. Au nanoparticles (AuNPs)-modified Boron-Doped Diamond (BDD) electrodes are fabricated by layer-by-layer (LBL) self-assembly technique and used for the direct electrochemistry of Shewanella loihica PV-4 in an electrochemical cell. Experimental results show that the peak current densities generated on the Au/PAH multilayer-modified BDD electrodes increased from 1.25 to 2.93 microA/cm(-2) as the layer increased from 0 to 6. Different cell morphologies of S. loihica PV-4 were also observed on the electrodes and the highest density of cells was attached on the (Au/PAH)6/BDD electrode with well-formed three-dimensional nanostructure. The electrochemistry of S. loihica PV-4 was enhanced on the (Au/PAH)4/BDD electrode due to the appropriate amount of AuNPsand thickness of PAH layer.

Masked polycythaemia vera: presenting features, response to treatment and clinical outcomes.

PubMed

Alvarez-Larrán, Alberto; Angona, Anna; Ancochea, Agueda; García-Pallarols, Francesc; Fernández, Concepción; Longarón, Raquel; Bellosillo, Beatriz; Besses, Carlos

2016-01-01

Masked polycythaemia vera (PV) has been proposed as a new entity with poorer outcome than overt PV. In this study, the initial clinical and laboratory characteristics, response to treatment and outcome of masked and overt PV were compared using red cell mass and haemoglobin or haematocrit levels for the distinction between both entities. Sixty-eight of 151 PV patients (45%) were classified as masked PV according to World Health Organisation diagnostic criteria, whereas 16 (11%) were classified as masked PV using the British Committee for Standards in Haematology (BCSH). In comparison with overt PV, a higher platelet count and a lower JAK2V617F allele burden at diagnosis were observed in masked PV. Patients with masked PV needed lower phlebotomies and responded faster to hydroxcarbamide than those with overt PV. Complete haematological response was more frequently achieved in masked than in overt PV (79% vs. 58%, P = 0.001). There were no significant differences in the duration of haematological response, the rate of resistance or intolerance to hydroxycarbamide and the probability of molecular response according to type of PV (masked vs. overt). Overall survival, rate of thrombosis and major bleeding, and probability of transformation was superimposable among patients with masked and overt PV. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Conjunction of Photovoltaic and Thermophotovoltaic Power Production in Spacecraft Power Systems

DTIC Science & Technology

2015-09-01

photovoltaic ( PV ) arrays, which draw electrical energy from the most prominent power source in our solar system, the Sun. These arrays are large, and pose...freemaps/1000px/dni/SolarGIS- Solar -map-DNI-World- map-en.png By contrast, spacecraft PV power production systems are not so limited. With the...operating parameters for a given solar cell, and PMax is generally the described Pout from which the PV cell’s efficiency is calculated. A PV cell’s

Fragmented red blood cells automated measurement is a useful parameter to exclude schistocytes on the blood film.

PubMed

Lesesve, J-F; Asnafi, V; Braun, F; Zini, G

2012-12-01

  The diagnosis of thrombotic microangiopathies (TMA) or disorders that may mimic their features remains difficult. Mechanical hemolytic anemia with the detection of shistocytes on the blood smear is a cornerstone finding to assess the diagnosis, but microscopic evaluation of shistocytes is still problematic with wide interobserver variations. Some of the latest generation automated blood cell counters (ABCC) propose an original quantitative approach of fragmented red cells (FRC), aiming to be equivalent to the microscopic count. This parameter has been poorly evaluated.   To assess the predictive value (PV) of this test, we conducted studies comparing automated and microscopic counts of FRC/schistocytes, based on the analysis of thousands samples in four university hospitals and using the 2 ABCC currently available (Siemens ADVIA series, Sysmex XE-2100). Reference range for FRC was <0.3% for the ADVIA and <0.5% for the XE-2100. The presence of FRC below a threshold determined at 1% (ADVIA and XE-2100) had a negative PV close to 100% to exclude the presence of schistocyte on the blood smear, but in relationship with a poor PV value. Our study validated the utility of the immediately available FRC parameter on ABCC to exclude schistocytes and the diagnosis of TMA. © 2012 Blackwell Publishing Ltd.

On-line monitoring system of PV array based on internet of things technology

NASA Astrophysics Data System (ADS)

Li, Y. F.; Lin, P. J.; Zhou, H. F.; Chen, Z. C.; Wu, L. J.; Cheng, S. Y.; Su, F. P.

2017-11-01

The Internet of Things (IoT) Technology is used to inspect photovoltaic (PV) array which can greatly improve the monitoring, performance and maintenance of the PV array. In order to efficiently realize the remote monitoring of PV operating environment, an on-line monitoring system of PV array based on IoT is designed in this paper. The system includes data acquisition, data gateway and PV monitoring centre (PVMC) website. Firstly, the DSP-TMS320F28335 is applied to collect indicators of PV array using sensors, then the data are transmitted to data gateway through ZigBee network. Secondly, the data gateway receives the data from data acquisition part, obtains geographic information via GPS module, and captures the scenes around PV array via USB camera, then uploads them to PVMC website. Finally, the PVMC website based on Laravel framework receives all data from data gateway and displays them with abundant charts. Moreover, a fault diagnosis approach for PV array based on Extreme Learning Machine (ELM) is applied in PVMC. Once fault occurs, a user alert can be sent via E-mail. The designed system enables users to browse the operating conditions of PV array on PVMC website, including electrical, environmental parameters and video. Experimental results show that the presented monitoring system can efficiently real-time monitor the PV array, and the fault diagnosis approach reaches a high accuracy of 97.5%.

Cell-type specific circuit connectivity of hippocampal CA1 revealed through Cre-dependent rabies tracing

PubMed Central

Sun, Yanjun; Nguyen, Amanda; Nguyen, Joseph; Le, Luc; Saur, Dieter; Choi, Jiwon; Callaway, Edward M.; Xu, Xiangmin

2014-01-01

Summary We applied a new Cre-dependent, genetically modified rabies-based tracing system to map direct synaptic connections to CA1 excitatory and inhibitory neuron types in mouse hippocampus. We found common inputs to excitatory and inhibitory CA1 neurons from CA3, CA2, entorhinal cortex and the medial septum (MS), and unexpectedly also from the subiculum. Excitatory CA1 neurons receive inputs from both cholinergic and GABAergic MS neurons while inhibitory CA1 neurons receive a great majority of input from GABAergic MS neurons; both cell types also receive weaker input from glutamatergic MS neurons. Comparisons of inputs to CA1 PV+ interneurons versus SOM+ interneurons showed similar strengths of input from the subiculum, but PV+ interneurons receive much stronger input than SOM+ neurons from CA3, entorhinal cortex and MS. Differential input from CA3 to specific CA1 cell types was also demonstrated functionally using laser scanning photostimulation and whole cell recordings. PMID:24656815

Facilitated extracellular electron transfer of Shewanella loihica PV-4 by antimony-doped tin oxide nanoparticles as active microelectrodes.

PubMed

Zhang, Xiaojian; Liu, Huan; Wang, Jinrong; Ren, Guangyuan; Xie, Beizhen; Liu, Hong; Zhu, Ying; Jiang, Lei

2015-11-28

Dissimilatory metal reducing bacteria are capable of extracellular electron transfer (EET) to insoluble metal oxides as external electron acceptors for their anaerobic respiration, which is recognized as an important energy-conversion process in natural and engineered environments, such as in mineral cycling, bioremediation, and microbial fuel/electrolysis cells. However, the low EET efficiency remains one of the major bottlenecks for its practical application. We report firstly that the microbial current generated by Shewanella loihica PV-4 (S. loihica PV-4) could be greatly improved that is up to ca. 115 fold, by adding antimony-doped tin oxide (ATO) nanoparticles in the electrochemical reactor. The results demonstrate that the biocompatible, electrically conductive ATO nanoparticles acted as active microelectrodes could facilitate the formation of a cells/ATO composite biofilm and the reduction of the outer membrane c-type cytochromes (OM c-Cyts) that are beneficial for the electron transfer from cells to electrode. Meanwhile, a synergistic effect between the participation of OM c-Cyts and the accelerated EET mediated by cell-secreted flavins may play an important role for the enhanced current generation in the presence of ATO nanoparticles. Moreover, it is worth noting that the TCA cycle in S. loihica PV-4 cells is activated by adding ATO nanoparticles, even if the potential is poised at +0.2 V, thereby also improving the EET process. The results presented here may provide a simple and effective strategy to boost the EET of S. loihica PV-4 cells, which is conducive to providing potential applications in bioelectrochemical systems.

The Coxiella Burnetii type IVB secretion system (T4BSS) component DotA is released/secreted during infection of host cells and during in vitro growth in a T4BSS-dependent manner.

PubMed

Luedtke, Brandon E; Mahapatra, Saugata; Lutter, Erika I; Shaw, Edward I

2017-06-01

Coxiella burnetii is a Gram-negative intracellular pathogen and is the causative agent of the zoonotic disease Q fever. To cause disease, C. burnetii requires a functional type IVB secretion system (T4BSS) to transfer effector proteins required for the establishment and maintenance of a membrane-bound parasitophorous vacuole (PV) and further modulation of host cell process. However, it is not clear how the T4BSS interacts with the PV membrane since neither a secretion pilus nor an extracellular pore forming apparatus has not been described. To address this, we used the acidified citrate cysteine medium (ACCM) along with cell culture infection and immunological techniques to identify the cellular and extracellular localization of T4BSS components. Interestingly, we found that DotA and IcmX were secreted/released in a T4BSS-dependent manner into the ACCM. Analysis of C. burnetii-infected cell lines revealed that DotA colocalized with the host cell marker CD63 (LAMP3) at the PV membrane. In the absence of bacterial protein synthesis, DotA also became depleted from the PV membrane. These data are the first to identify the release/secretion of C. burnetii T4BSS components during axenic growth and the interaction of a T4BSS component with the PV membrane during infection of host cells. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

On enhancing energy harvesting performance of the photovoltaic modules using an automatic cooling system and assessing its economic benefits of mitigating greenhouse effects on the environment

NASA Astrophysics Data System (ADS)

Wang, Jen-Cheng; Liao, Min-Sheng; Lee, Yeun-Chung; Liu, Cheng-Yue; Kuo, Kun-Chang; Chou, Cheng-Ying; Huang, Chen-Kang; Jiang, Joe-Air

2018-02-01

The performance of photovoltaic (PV) modules under outdoor operation is greatly affected by their location and environmental conditions. The temperature of a PV module gradually increases as it is exposed to solar irradiation, resulting in degradation of its electrical characteristics and power generation efficiency. This study adopts wireless sensor network (WSN) technology to develop an automatic water-cooling system for PV modules in order to improve their PV power generation efficiency. A temperature estimation method is developed to quickly and accurately estimate the PV module temperatures based on weather data provided from the WSN monitoring system. Further, an estimation method is also proposed for evaluation of the electrical characteristics and output power of the PV modules, which is performed remotely via a control platform. The automatic WSN-based water-cooling mechanism is designed to avoid the PV module temperature from reaching saturation. Equipping each PV module with the WSN-based cooling system, the ambient conditions are monitored automatically so that the temperature of the PV module is controlled by sprinkling water on the panel surface. The field-test experiment results show an increase in the energy harvested by the PV modules of approximately 17.75% when using the proposed WSN-based cooling system.

Small photovoltaic setup for the air conditioning system

NASA Astrophysics Data System (ADS)

Masiukiewicz, Maciej

2017-10-01

The increasing interest in air conditioning systems for residential applications in Poland will certainly increase the demand for electricity during the summer period. Due to this fact a growing interest in solutions that help to lower the electricity consumption in this sector is observed. The problem of increased energy demand for air conditioning purposes can be solved by transfer the consumption of electricity from the grid system to renewable energy sources (RES). The greatest demand for cooling occurs during the biggest sunlight. This is the basis for the analysis of technical power system based on photovoltaic cells (PV) to power the split type air conditioner. The object of the study was the commercial residential airconditioning inverter units with a capacity of 2.5kW. A network electricity production system for their own use with the possibility of buffering energy in batteries (OFF-GRID system). Currently, on the Polish market, there are no developed complete solutions dedicated to air conditioning systems based on PV. In Poland, solar energy is mainly used for heat production in solar collectors. The proposed solution will help to increase the popularity of PV systems in the Polish market as an alternative to other RES. The basic conclusion is that the amount of PV energy generated was sufficient to cover the daily energy requirement of the air conditioner.

Detection of Papillomavirus DNA in Cutaneous Squamous Cell Carcinoma and Multiple Papillomas in Captive Reptiles.

PubMed

Eleni, C; Corteggio, A; Altamura, G; Meoli, R; Cocumelli, C; Rossi, G; Friedrich, K G; Di Cerbo, P; Borzacchiello, G

2017-07-01

Papillomaviruses (PVs) are small, non-enveloped DNA viruses that cause mucocutaneous tumours including squamous cell carcinoma (SCC) in man. In animals, evidence supports a causal role for PVs in the development of cutaneous and oral SCC in some species. In reptiles, three cases of papilloma or fibropapilloma have been associated with PV infection, but no association has been reported to date with SCC. Two cases of cutaneous epithelial tumours, multiple papillomas in a spiny-tailed lizard (Uromastyx acanthinura) and SCC in a Dumeril's boa (Acrantophis dumerili), were investigated by polymerase chain reaction. PV DNA was amplified from samples of both lesions. Typical microscopical features suggestive of PV infection (e.g. the presence of koilocytes) were observed in the lesions from the spiny-tailed lizard. This is the first report of an association between PV and SCC in reptiles. Further studies are needed to better clarify the role of PVs in these species and to characterize the PV strains involved. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analyzing the Energy Performance, Wind Loading, and Costs of Photovoltaic Slat Modules on Commercial Rooftops

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Geet, Otto D.; Fu, Ran; Horowitz, Kelsey A.

NREL studied a new type of photovoltaic (PV) module configuration wherein multiple narrow, tilted slats are mounted in a single frame. Each slat of the PV slat module contains a single row of cells and is made using ordinary crystalline silicon PV module materials and processes, including a glass front sheet and weatherproof polymer encapsulation. Compared to a conventional ballasted system, a system using slat modules offer higher energy production and lower weight at lower LCOE. The key benefits of slat modules are reduced wind loading, improved capacity factor and reduced installation cost. First, the individual slats allow air tomore » flow through, which reduce wind loading. Using PV performance modeling software, we compared the performance of an optimized installation of slats modules to a typical installation of conventional modules in a ballasted rack mounting system. Based on the results of the performance modeling two different row tilt and spacing were tested in a wind tunnel. Scaled models of the PV Slat modules were wind tunnel tested to quantify the wind loading of a slat module system on a commercial rooftop, comparing the results to conventional ballasted rack mounted PV modules. Some commercial roofs do not have sufficient reserve dead load capacity to accommodate a ballasted system. A reduced ballast system design could make PV system installation on these roofs feasible for the first time without accepting the disadvantages of penetrating mounts. Finally, technoeconomic analysis was conducted to enable an economic comparison between a conventional commercial rooftop system and a reduced-ballast slat module installation.« less

Comparison of efficiency degradation in polycrystalline-Si and CdTe thin-film PV modules via accelerated lifecycle testing

NASA Astrophysics Data System (ADS)

Lai, T.; Potter, B. G.; Simmons-Potter, K.

2017-08-01

Thin-film solar cells normally have the shortest energy payback time due to their simpler mass-production process compared to polycrystalline-Si photovoltaic (PV) modules, despite the fact that crystalline-Si-based technology typically has a longer total lifetime and a higher initial power conversion efficiency. For both types of modules, significant aging occurs during the first two years of usage with slower long-term aging over the module lifetime. The PV lifetime and the return-on-investment for local PV system installations rely on long-term device performance. Understanding the efficiency degradation behavior under a given set of environmental conditions is, therefore, a primary goal for experimental research and economic analysis. In the present work, in-situ measurements of key electrical characteristics (J, V, Pmax, etc.) in polycrystalline-Si and CdTe thin-film PV modules have been analyzed. The modules were subjected to identical environmental conditions, representative of southern Arizona, in a full-scale, industrial-standard, environmental degradation chamber, equipped with a single-sun irradiance source, temperature, and humidity controls, and operating an accelerated lifecycle test (ALT) sequence. Initial results highlight differences in module performance with environmental conditions, including temperature de-rating effects, for the two technologies. Notably, the thin-film CdTe PV module was shown to be approximately 15% less sensitive to ambient temperature variation. After exposure to a seven-month equivalent compressed night-day weather cycling regimen the efficiency degradation rates of both PV technology types were obtained and will be discussed.

The Oncolytic Virotherapy Era in Cancer Management: Prospects of Applying H-1 Parvovirus to Treat Blood and Solid Cancers

PubMed Central

Angelova, Assia L.; Witzens-Harig, Mathias; Galabov, Angel S.; Rommelaere, Jean

2017-01-01

Non-Hodgkin lymphoma (NHL) and leukemia are among the most common cancers worldwide. While the treatment of NHL/leukemia of B-cell origin has much progressed with the introduction of targeted therapies, few treatment standards have been established for T-NHL/leukemia. As presentation in both B- and T-NHL/leukemia patients is often aggressive and as prognosis for relapsed disease is especially dismal, this cancer entity poses major challenges and requires innovative therapeutic approaches. In clinical trials, oncolytic viruses (OVs) have been used against refractory multiple myeloma (MM). In preclinical settings, a number of OVs have demonstrated a remarkable ability to suppress various types of hematological cancers. Most studies dealing with this approach have used MM or B- or myeloid-cell-derived malignancies as models. Only a few describe susceptibility of T-cell lymphoma/leukemia to OV infection and killing. The rat H-1 parvovirus (H-1PV) is an OV with considerable promise as a novel therapeutic agent against both solid tumors (pancreatic cancer and glioblastoma) and hematological malignancies. The present perspective article builds on previous reports of H-1PV-driven regression of Burkitt’s lymphoma xenografts and on unpublished observations demonstrating effective killing by H-1PV of cells from CHOP-resistant diffuse large B-cell lymphoma, cutaneous T-cell lymphoma, and T-cell acute lymphoblastic leukemia. On the basis of these studies, H-1PV is proposed for use as an adjuvant to (chemo)therapeutic regimens. Furthermore, in the light of a recently completed first parvovirus clinical trial in glioblastoma patients, the advantages of H-1PV for systemic application are discussed. PMID:28553616

Advanced Thermal Conversion Systems

DTIC Science & Technology

2015-03-18

increase electron emission from the cathode. A two-stage, PETE topping stage followed by a thermoelectric bottoming stage, is projected to have a...illustrated in the by the energy-band diagrams in Fig. 1. In that aspect, PETE converters are similar to photovoltaic (PV) cells, but unlike PV cells, PETE... photovoltaic cells at 3000x concentration (~38%). As shown in Fig. 2(b), the highest conversion efficiencies are obtained by using photo-cathodes

Comparative RNAi screening reveals host factors involved in enterovirus infection of polarized endothelial monolayers.

PubMed

Coyne, Carolyn B; Bozym, Rebecca; Morosky, Stefanie A; Hanna, Sheri L; Mukherjee, Amitava; Tudor, Matthew; Kim, Kwang Sik; Cherry, Sara

2011-01-20

Enteroviruses, including coxsackievirus B (CVB) and poliovirus (PV), can access the CNS through the blood brain barrier (BBB) endothelium to cause aseptic meningitis. To identify cellular components required for CVB and PV infection of human brain microvascular endothelial cells, an in vitro BBB model, we performed comparative RNAi screens and identified 117 genes that influenced infection. Whereas a large proportion of genes whose depletion enhanced infection (17 of 22) were broadly antienteroviral, only 46 of the 95 genes whose depletion inhibited infection were required by both CVB and PV and included components of cell signaling pathways such as adenylate cyclases. Downregulation of genes including Rab GTPases, Src tyrosine kinases, and tyrosine phosphatases displayed specificity in their requirement for either CVB or PV infection. These findings highlight the pathways hijacked by enteroviruses for entry and replication in the BBB endothelium, a specialized and clinically relevant cell type for these viruses. Copyright © 2011 Elsevier Inc. All rights reserved.

Performance of double -pass solar collector with CPC and fins for heat transfer enhancement

NASA Astrophysics Data System (ADS)

Alfegi, Ebrahim M. A.; Abosbaia, Alhadi A. S.; Mezughi, Khaled M. A.; Sopian, Kamaruzzaman

2013-06-01

The temperature of photovoltaic modules increases when it absorbs solar radiation, causing a decrease in efficiency. This undesirable effect can be partially avoided by applying a heat recovery unit with fluid circulation (air or water) with the photovoltaic module. Such unit is called photovoltaic / thermal collector (pv/t) or hybrid (pv/t). In this unit, photovoltaic cells were pasted directly on the flat plate absorber. An experimental study of a solar air heater with photovoltaic cell located at the absorber with fins and compound parabolic collector for heat transfer enhancement and increasing the number of reflection on the cells have been conducted. The performance of the photovoltaic, thermal, and combined pv/t collector over range of operating conditions and the results was discussed. Results at solar irradiance of 500 W/m2 show that the combined pv/t efficiency is increasing from 37.28 % to 81.41 % at mass flow rates various from 0.029 to 0.436 kg/s.

Parvalbumin-positive interneurons mediate neocortical-hippocampal interactions that are necessary for memory consolidation

PubMed Central

Xia, Frances; Richards, Blake A; Tran, Matthew M; Josselyn, Sheena A

2017-01-01

Following learning, increased coupling between spindle oscillations in the medial prefrontal cortex (mPFC) and ripple oscillations in the hippocampus is thought to underlie memory consolidation. However, whether learning-induced increases in ripple-spindle coupling are necessary for successful memory consolidation has not been tested directly. In order to decouple ripple-spindle oscillations, here we chemogenetically inhibited parvalbumin-positive (PV+) interneurons, since their activity is important for regulating the timing of spiking activity during oscillations. We found that contextual fear conditioning increased ripple-spindle coupling in mice. However, inhibition of PV+ cells in either CA1 or mPFC eliminated this learning-induced increase in ripple-spindle coupling without affecting ripple or spindle incidence. Consistent with the hypothesized importance of ripple-spindle coupling in memory consolidation, post-training inhibition of PV+ cells disrupted contextual fear memory consolidation. These results indicate that successful memory consolidation requires coherent hippocampal-neocortical communication mediated by PV+ cells. PMID:28960176

Precision Controlled Carbon Materials for Next-Generation Optoelectronic and Photonic Devices

DTIC Science & Technology

2018-01-08

absorbers. Semiconducting nanotubes are strong, dye-like absorbers with bandgaps tunable to the ideal for single-junction solar PV ~1.3 eV or deeper...semiconducting carbon nanotube-based photovoltaic solar cells and photodetectors; (2) high-performance carbon nanotube electronics; (3) stretchable...photovoltaic solar cells and photodetectors Semiconducting carbon nanotubes are attractive absorbers for photovoltaic and photodetector devices. The

Impact of distributed power electronics on the lifetime and reliability of PV systems: Impact of distributed power electronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olalla, Carlos; Maksimovic, Dragan; Deline, Chris

Here, this paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affectmore » the overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. Lastly, it is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

Impact of distributed power electronics on the lifetime and reliability of PV systems: Impact of distributed power electronics

DOE PAGES

Olalla, Carlos; Maksimovic, Dragan; Deline, Chris; ...

2017-04-26

Here, this paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affectmore » the overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. Lastly, it is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

A miniature solar device for overall water splitting consisting of series-connected spherical silicon solar cells

PubMed Central

Kageshima, Yosuke; Shinagawa, Tatsuya; Kuwata, Takaaki; Nakata, Josuke; Minegishi, Tsutomu; Takanabe, Kazuhiro; Domen, Kazunari

2016-01-01

A novel “photovoltaics (PV) + electrolyzer” concept is presented using a simple, small, and completely stand-alone non-biased device for solar-driven overall water splitting. Three or four spherical-shaped p-n junction silicon balls were successfully connected in series, named “SPHELAR.” SPHELAR possessed small projected areas of 0.20 (3PVs) and 0.26 cm2 (4PVs) and exhibited working voltages sufficient for water electrolysis. Impacts of the configuration on the PV module performance were carefully analyzed, revealing that a drastic increase in the photocurrent (≈20%) was attained by the effective utilization of a reflective sheet. Separate investigations on the electrocatalyst performance showed that non-noble metal based materials with reasonably small sizes (<0.80 cm2) exhibited substantial currents at the PV working voltage. By combining the observations of the PV characteristics, light management and electrocatalyst performance, solar-driven overall water splitting was readily achieved, reaching solar-to-hydrogen efficiencies of 7.4% (3PVs) and 6.4% (4PVs). PMID:27087266

A miniature solar device for overall water splitting consisting of series-connected spherical silicon solar cells

NASA Astrophysics Data System (ADS)

Kageshima, Yosuke; Shinagawa, Tatsuya; Kuwata, Takaaki; Nakata, Josuke; Minegishi, Tsutomu; Takanabe, Kazuhiro; Domen, Kazunari

2016-04-01

A novel “photovoltaics (PV) + electrolyzer” concept is presented using a simple, small, and completely stand-alone non-biased device for solar-driven overall water splitting. Three or four spherical-shaped p-n junction silicon balls were successfully connected in series, named “SPHELAR.” SPHELAR possessed small projected areas of 0.20 (3PVs) and 0.26 cm2 (4PVs) and exhibited working voltages sufficient for water electrolysis. Impacts of the configuration on the PV module performance were carefully analyzed, revealing that a drastic increase in the photocurrent (≈20%) was attained by the effective utilization of a reflective sheet. Separate investigations on the electrocatalyst performance showed that non-noble metal based materials with reasonably small sizes (<0.80 cm2) exhibited substantial currents at the PV working voltage. By combining the observations of the PV characteristics, light management and electrocatalyst performance, solar-driven overall water splitting was readily achieved, reaching solar-to-hydrogen efficiencies of 7.4% (3PVs) and 6.4% (4PVs).

Efficient electroluminescent cooling with a light-emitting diode coupled to a photovoltaic cell (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xiao, Tianyao P.; Chen, Kaifeng; Santhanam, Parthiban; Fan, Shanhui; Yablonovitch, Eli

2017-02-01

The new breakthrough in photovoltaics, exemplified by the slogan "A great solar cell has to be a great light-emitting diode (LED)", has led to all the major new solar cell records, while also leading to extraordinary LED efficiency. As an LED becomes very efficient in converting its electrical input into light, the device cools as it operates because the photons carry away entropy as well as energy. If these photons are absorbed in a photovoltaic (PV) cell, the generated electricity can be used to provide part of the electrical input that drives the LED. Indeed, the LED/PV cell combination forms a new type of heat engine with light as the working fluid. The electroluminescent refrigerator requires only a small amount of external electricity to provide cooling, leading to a high coefficient of performance. We present the theoretical performance of such a refrigerator, in which the cool side (LED) is radiatively coupled to the hot side (PV) across a vacuum gap. The coefficient of performance is maximized by using a highly luminescent material, such as GaAs, together with device structures that optimize extraction of the luminescence. We consider both a macroscopic vacuum gap and a sub-wavelength gap; the latter allows for evanescent coupling of photons between the devices, potentially providing a further enhancement to the efficiency of light extraction. Using device assumptions based on the current record-efficiency solar cells, we show that electroluminescent cooling can, in certain regimes of cooling power, achieve a higher coefficient of performance than thermoelectric cooling.

Recombineering Pseudomonas syringae

USDA-ARS?s Scientific Manuscript database

Here we report the identification of functions that promote genomic recombination of linear DNA introduced into Pseudomonas cells by electroporation. The genes encoding these functions were identified in Pseudomonas syringae pv. syringae B728a based on similarity to the lambda Red Exo/Beta and RecE...

Removal of GABAA Receptor γ2 Subunits from Parvalbumin Neurons Causes Wide-Ranging Behavioral Alterations

PubMed Central

Leppä, Elli; Linden, Anni-Maija; Vekovischeva, Olga Y.; Swinny, Jerome D.; Rantanen, Ville; Toppila, Esko; Höger, Harald; Sieghart, Werner; Wulff, Peer; Wisden, William; Korpi, Esa R.

2011-01-01

We investigated the behavioral significance of fast synaptic inhibition by αβγ2-type GABAA receptors on parvalbumin (Pv) cells. The GABAA receptor γ2 subunit gene was selectively inactivated in Pv-positive neurons by Cre/loxP recombination. The resulting Pv-Δγ2 mice were relatively healthy in the first postnatal weeks; but then as Cre started to be expressed, the mice progressively developed wide-ranging phenotypic alterations including low body weight, motor deficits and tremor, decreased anxiety levels, decreased pain sensitivity and deficient prepulse inhibition of the acoustic startle reflex and impaired spatial learning. Nevertheless, the deletion was not lethal, and mice did not show increased mortality even after one year. Autoradiography with t-butylbicyclophosphoro[35S]thionate suggested an increased amount of GABAA receptors with only α and β subunits in central nervous system regions that contained high levels of parvalbumin neurons. Using BAC-transgenesis, we reduced some of the Pv-Δγ2 phenotype by selectively re-expressing the wild-type γ2 subunit back into some Pv cells (reticular thalamic neurons and cerebellar Pv-positive neurons). This produced less severe impairments of motor skills and spatial learning compared with Pv-Δγ2 mice, but all other deficits remained. Our results reveal the widespread significance of fast GABAergic inhibition onto Pv-positive neurons for diverse behavioral modalities, such as motor coordination, sensorimotor integration, emotional behavior and nociception. PMID:21912668

Photovoltaic fabrics

DTIC Science & Technology

2015-04-22

CLADDING SOLAR CELLS PV (PHOTOVOLTAIC) University of Massachusetts – Dartmouth 285 Old Westport Road Dartmouth, MA 02747...Lowell, MA 01852 14. ABSTRACT This report describes a project to improve photovoltaic fabrics. It had four objectives: 1) Efficiency – make PV wires on...direct sunlight (AM1.5). Over the duration of the project we demonstrated PV efficiency ranging from 5.04% (wire on a black background) to >8

Angle-depended photocurrent characteristics of cascade photoelectric converters on the base of homogeneous semiconductor

NASA Astrophysics Data System (ADS)

Arbuzov, Yuri D.; Evdokimov, Vladimir M.; Shepovalova, Olga V.

2018-05-01

Angle-dependent spectral photoresponse characteristics for theoretically perfect and physically implementable tunnel cascade (multi-junction) photoelectric converters (PC), for example high-voltage planar PV cells, have been studied as functions of technological parameters and number of single PCs in cascade. Angle-dependent spectral photoresponse characteristics values for real cascade silicon structures have been determined in visible and ultraviolet radiation spectra. Characteristic values of radiation incidence angle corresponding to the twofold photocurrent reduction in relation to normal incidence have been found depending on the number of single PCs in cascade, `dead' layer thickness of tunnel junction and photosensitivity of the base PC. The possibility and practicability of solar trackers use in PV systems with proposed PCs under study have been evaluated.

Host lipid droplets: An important source of lipids salvaged by the intracellular parasite Toxoplasma gondii

PubMed Central

Romano, Julia D.

2017-01-01

Toxoplasma is an obligate intracellular parasite that replicates in mammalian cells within a parasitophorous vacuole (PV) that does not fuse with any host organelles. One mechanism developed by the parasite for nutrient acquisition is the attraction of host organelles to the PV. Here, we examined the exploitation of host lipid droplets (LD), ubiquitous fat storage organelles, by Toxoplasma. We show that Toxoplasma replication is reduced in host cells that are depleted of LD, or impaired in TAG lipolysis or fatty acid catabolism. In infected cells, the number of host LD and the expression of host LD-associated genes (ADRP, DGAT2), progressively increase until the onset of parasite replication. Throughout infection, the PV are surrounded by host LD. Toxoplasma is capable of accessing lipids stored in host LD and incorporates these lipids into its own membranes and LD. Exogenous addition of oleic acid stimulates LD biogenesis in the host cell and results in the overaccumulation of neutral lipids in very large LD inside the parasite. To access LD-derived lipids, Toxoplasma intercepts and internalizes within the PV host LD, some of which remaining associated with Rab7, which become wrapped by an intravacuolar network of membranes (IVN). Mutant parasites impaired in IVN formation display diminished capacity of lipid uptake from host LD. Moreover, parasites lacking an IVN-localized phospholipase A2 are less proficient in salvaging lipids from host LD in the PV, suggesting a major contribution of the IVN for host LD processing in the PV and, thus lipid content release. Interestingly, gavage of parasites with lipids unveils, for the first time, the presence in Toxoplasma of endocytic-like structures containing lipidic material originating from the PV lumen. This study highlights the reliance of Toxoplasma on host LD for its intracellular development and the parasite’s capability in scavenging neutral lipids from host LD. PMID:28570716

Photovoltaic energy program overview, fiscal year 1991

NASA Astrophysics Data System (ADS)

1992-02-01

The Photovoltaics Program Plan, FY 1991 to FY 1995 builds on the accomplishments of the past 5 years and broadens the scope of program activities for the future. The previous plan emphasized materials and PV cell research. Under the balanced new plan, the PV Program continues its commitment to strategic research and development (R&D) into PV materials and processes, while also beginning work on PV systems and helping the PV industry encourage new markets for photovoltaics. A major challenge for the program is to assist the US PV industry in laying the foundation for at least 1000 MW of installed PV capacity in the United States and 500 MW internationally by 2000. As part of the new plan, the program expanded the scope of its activities in 1991. The PV Program is now addressing many new aspects of developing and commercializing photovoltaics. It is expanding activities with the US PV industry through the PV Manufacturing Technology (PVMaT) project, designed to address US manufacturers' immediate problems; providing technical assistance to potential end users such as electric utilities; and the program is turning its attention to encouraging new markets for PV. In 1991, for example, the PV Program initiated a new project with the PV industry to encourage a domestic market for PV applications in buildings and began cooperative ventures to support other countries such as Mexico to use PV in their rural electrification programs. This report reviews some of the development, fabrication and manufacturing advances in photovoltaics this year.

A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions

PubMed Central

Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C.

2015-01-01

This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper. PMID:26230694

A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions.

PubMed

Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C

2015-07-29

This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper.

Beyond Punnett squares: Student word association and explanations of phenotypic variation through an integrative quantitative genetics unit investigating anthocyanin inheritance and expression in Brassica rapa Fast plants.

PubMed

Batzli, Janet M; Smith, Amber R; Williams, Paul H; McGee, Seth A; Dósa, Katalin; Pfammatter, Jesse

2014-01-01

Genetics instruction in introductory biology is often confined to Mendelian genetics and avoids the complexities of variation in quantitative traits. Given the driving question "What determines variation in phenotype (Pv)? (Pv=Genotypic variation Gv + environmental variation Ev)," we developed a 4-wk unit for an inquiry-based laboratory course focused on the inheritance and expression of a quantitative trait in varying environments. We utilized Brassica rapa Fast Plants as a model organism to study variation in the phenotype anthocyanin pigment intensity. As an initial curriculum assessment, we used free word association to examine students' cognitive structures before and after the unit and explanations in students' final research posters with particular focus on variation (Pv = Gv + Ev). Comparison of pre- and postunit word frequency revealed a shift in words and a pattern of co-occurring concepts indicative of change in cognitive structure, with particular focus on "variation" as a proposed threshold concept and primary goal for students' explanations. Given review of 53 posters, we found ∼50% of students capable of intermediate to high-level explanations combining both Gv and Ev influence on expression of anthocyanin intensity (Pv). While far from "plug and play," this conceptually rich, inquiry-based unit holds promise for effective integration of quantitative and Mendelian genetics. © 2014 J. M. Batzli et al. CBE—Life Sciences Education © 2014 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Enhanced Contacts for Inverted Metamorphic Multi-Junction Solar Cells Using Carbon Nanotube Metal Matrix Composites

DTIC Science & Technology

2018-01-18

to a variety solar energy markets. For instance, micro-cracks have been shown to cause decreased power output in single- and multi-crystalline Si PV ...fingers in silicon wafer solar cells and PV modules," Solar Energy Materials and Solar Cells, vol. 108, pp. 78-81, 1// 2013. [4] T. H. Reijenga and H...AFRL-RV-PS- AFRL-RV-PS- TR-2017-0125 TR-2017-0125 ENHANCED CONTACTS FOR INVERTED METAMORPHIC MULTI-JUNCTION SOLAR CELLS USING CARBON NANOTUBE METAL

Mechanisms of Thrombogenesis in Polycythemia Vera

PubMed Central

Kroll, Michael H.; Michaelis, Laura C.; Verstovsek, Srdan

2015-01-01

Thrombotic and cardiovascular events are among the leading causes of death for patients with polycythemia vera (PV), and thrombosis history is a key criterion for patient risk stratification and treatment strategy. Little is known, however, about mechanisms of thrombogenesis in patients with PV. This report provides an overview of thrombogenesis pathophysiology in patients with PV and elucidates the roles of conventional and nonconventional thrombosis risk factors. In addition to several conventional risk factors for thrombosis, clinical data have implicated increased hematocrit and red blood cell adhesiveness, activated platelets, leukocytosis, and elevated JAK2V617F allele burden in patients with PV. Furthermore, PV-related inflammation may exacerbate thrombogenesis through varied mechanisms, including endothelial damage, inhibition of natural anticoagulant pathways, and secretion of procoagulant factors. These findings suggest a direct link between myeloproliferation and thrombogenesis in PV, which is likely to provide new opportunities for targeted antithrombotic interventions aimed at decreasing PV-related morbidity and mortality. PMID:25577686

Tritium power source for long-lived sensors

NASA Astrophysics Data System (ADS)

Litz, M. S.; Katsis, D. C.; Russo, J. A.; Carroll, J. J.

2014-06-01

A tritium-based indirect converting photovoltaic (PV) power source has been designed and prototyped as a long-lived (~15 years) power source for sensor networks. Tritium is a biologically benign beta emitter and low-cost isotope acquired from commercial vendors for this purpose. The power source combines tritium encapsulated with a radioluminescent phosphor coupled to a commercial PV cell. The tritium, phosphor, and PV components are packaged inside a BA5590-style military-model enclosure. The package has been approved by the nuclear regulatory commission (NRC) for use by DOD. The power source is designed to produce 100μW electrical power for an unattended radiation sensor (scintillator and avalanche photodiode) that can detect a 20 μCi source of 137Cs at three meters. This beta emitting indirect photon conversion design is presented as step towards the development of practical, logistically acceptable, lowcost long-lived compact power sources for unattended sensor applications in battlefield awareness and environmental detection.

Quarterly Report: Microchannel-Assisted Nanomaterial Deposition Technology for Photovoltaic Material Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palo, Daniel R.

2011-04-26

Quarterly report to ITP for Nanomanufacturing program. Report covers FY11 Q2. The primary objective of this project is to develop a nanomanufacturing process which will reduce the manufacturing energy, environmental discharge, and production cost associated with current nano-scale thin-film photovoltaic (PV) manufacturing approaches. The secondary objective is to use a derivative of this nanomanufacturing process to enable greener, more efficient manufacturing of higher efficiency quantum dot-based photovoltaic cells now under development. The work is to develop and demonstrate a scalable (pilot) microreactor-assisted nanomaterial processing platform for the production, purification, functionalization, and solution deposition of nanomaterials for photovoltaic applications. The highmore » level task duration is shown. Phase I consists of a pilot platform for Gen II PV films along with parallel efforts aimed at Gen III PV quantum dot materials. Status of each task is described.« less

Neuropeptide Y as a possible homeostatic element for changes in cortical excitability induced by repetitive transcranial magnetic stimulation.

PubMed

Jazmati, Danny; Neubacher, Ute; Funke, Klaus

2018-02-24

Repetitive transcranial magnetic stimulation (rTMS) is able to modify cortical excitability. Rat rTMS studies revealed a modulation of inhibitory systems, in particular that of the parvalbumin-expressing (PV+) interneurons, when using intermittent theta-burst stimulation (iTBS). The potential disinhibitory action of iTBS raises the questions of how neocortical circuits stabilize excitatory-inhibitory balance within a physiological range. Neuropeptide Y (NPY) appears to be one candidate. Analysis of cortical expression of PV, NPY and vesicular glutamate transporter type 1 (vGluT1) by immunohistochemical means at the level of cell counts, mean neuropil expression and single cell pre-/postsynaptic expression, with and without intraventricular NPY-injection. Our results show that iTBS not only reduced the number of neurons with high-PV expression in a dose-dependent fashion, but also increased the cortical expression of NPY, discussed to reduce glutamatergic transmission, and this was further associated with a reduced vGluT1 expression, an indicator of glutamateric presynaptic activity. Interneurons showing a low-PV expression exhibit less presynaptic vGluT1 expression compared to those with a high-PV expression. Intraventricular application of NPY prior to iTBS prevented the iTBS-induced reduction in the number of high-PV neurons, the reduction in tissue vGluT1 level and that presynaptic to high-PV cells. We conclude that NPY, possibly via a global but also slow homeostatic control of glutamatergic transmission, modulates the strength and direction of the iTBS effects, likely preventing pathological imbalance of excitatory and inhibitory cortical activity but still allowing enough disinhibition beneficial for plastic changes as during learning. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Variable responses of small and large human hepatocytes to hypoxia and hypoxia/reoxygenation (H–R)

PubMed Central

Bhogal, Ricky H.; Weston, Christopher J.; Curbishley, Stuart M.; Bhatt, Anand N.; Adams, David H.; Afford, Simon C.

2011-01-01

Hypoxia and hypoxia–reoxygenation (H–R) regulate human hepatocyte cell death by mediating the accumulation of reactive oxygen species (ROS). Hepatocytes within the liver are organised into peri-portal (PP) and peri-venous (PV) subpopulations. PP and PV hepatocytes differ in size and function. We investigated whether PP and PV human hepatocytes exhibit differential susceptibility to hypoxic stress. Isolated hepatocytes were used in an in vitro model of hypoxia and H–R. ROS production and cell death were assessed using flow cytometry. PV, and not PP hepatocytes, accumulate intracellular ROS in a mitochondrial dependent manner during hypoxia and H–R. This increased ROS regulates hepatocyte apoptosis and necrosis via a mitochondrial pathway. These findings have implications on the understanding of liver injury and application of potential therapeutic strategies. PMID:21356211

Research on Potential Induced Degradation (PID) of PV Modules in Different Typical Climate Regions

NASA Astrophysics Data System (ADS)

Daoren, Gong; Yingnan, Chen; Gang, Sun; Wenjing, Wang; Zhenshuang, Ji

2018-03-01

Potential Induced Degradation (PID) is one of the most important factors effecting the performances of Photovoltaic (PV) modules and PV systems in recent years. In this paper the PID phenomena of the PV power plant in different typical climate regions were studied and some experimental PID simulations were carried out in order to find out the factors effecting the performance by PID. The results show that the typical PID phenomena are easy to occur in cells close to the border of the PV module. PID phenomena can appear in PV power plants under different climate conditions, but the effecting degrees on module performance are different depending on temperature, humidity and other parameters. We also find the maximum power would recover in some degree after positive-bias voltage duration.

Poor Prognosis Indicated by Venous Circulating Tumor Cell Clusters in Early-Stage Lung Cancers.

PubMed

Murlidhar, Vasudha; Reddy, Rishindra M; Fouladdel, Shamileh; Zhao, Lili; Ishikawa, Martin K; Grabauskiene, Svetlana; Zhang, Zhuo; Lin, Jules; Chang, Andrew C; Carrott, Philip; Lynch, William R; Orringer, Mark B; Kumar-Sinha, Chandan; Palanisamy, Nallasivam; Beer, David G; Wicha, Max S; Ramnath, Nithya; Azizi, Ebrahim; Nagrath, Sunitha

2017-09-15

Early detection of metastasis can be aided by circulating tumor cells (CTC), which also show potential to predict early relapse. Because of the limited CTC numbers in peripheral blood in early stages, we investigated CTCs in pulmonary vein blood accessed during surgical resection of tumors. Pulmonary vein (PV) and peripheral vein (Pe) blood specimens from patients with lung cancer were drawn during the perioperative period and assessed for CTC burden using a microfluidic device. From 108 blood samples analyzed from 36 patients, PV had significantly higher number of CTCs compared with preoperative Pe ( P < 0.0001) and intraoperative Pe ( P < 0.001) blood. CTC clusters with large number of CTCs were observed in 50% of patients, with PV often revealing larger clusters. Long-term surveillance indicated that presence of clusters in preoperative Pe blood predicted a trend toward poor prognosis. Gene expression analysis by RT-qPCR revealed enrichment of p53 signaling and extracellular matrix involvement in PV and Pe samples. Ki67 expression was detected in 62.5% of PV samples and 59.2% of Pe samples, with the majority (72.7%) of patients positive for Ki67 expression in PV having single CTCs as opposed to clusters. Gene ontology analysis revealed enrichment of cell migration and immune-related pathways in CTC clusters, suggesting survival advantage of clusters in circulation. Clusters display characteristics of therapeutic resistance, indicating the aggressive nature of these cells. Thus, CTCs isolated from early stages of lung cancer are predictive of poor prognosis and can be interrogated to determine biomarkers predictive of recurrence. Cancer Res; 77(18); 5194-206. ©2017 AACR . ©2017 American Association for Cancer Research.

Graphene nanoplatelet doping of P3HT:PCBM photoactive layer of bulk heterojunction organic solar cells for enhancing performance

NASA Astrophysics Data System (ADS)

Aïssa, Brahim; Nedil, Mourad; Kroeger, Jens; Ali, Adnan; Isaifan, Rima J.; Essehli, Rachid; Mahmoud, Khaled A.

2018-03-01

Hybrid organic photovoltaic (OPV) cells based on conjugated polymer photoactive materials are promising candidates for flexible, high-performance and low-cost energy sources owing to their inexpensive materials, cost-effective processing and ease of fabrication by simple solution processes. However, the modest PV performance obtained to date—in particular the low power conversion efficiency (PCE)—has impeded the large scale deployment of OPV cells. The low PCE in OPV solar cells is mainly attributed to the low carrier mobility, which is closely correlated to the transport diffusion length of the charge carriers within the photoactive layers. The 2D graphene material could be an excellent candidate for assisting charge transport improvement in the active layer of OPV cells, due to its huge carrier mobility, thermal and chemical stability, and its compatibility with the solution process. In this work, we report on the improvement of the optoelectronic properties and photovoltaic performance of graphene nanoplatelet (GNP)-doped P3HT:PCBM photoactive blended layers, integrated into a bulk heterojunction (BHJ) organic-photovoltaic-based device, using PEDOT:PSS on an ITO/glass substrate. First, the light absorption capacity was observed to increase with respect to the GNP content, while the photoluminescence showed clear quenching, indicating electron transfer between the graphene sheets and the polymeric matrix. Then, the incorporation of GNP into the BHJ active layer resulted in enhanced PV performance with respect to the reference cell, and the best PV performance was obtained with 3 wt.% of GNP loading, with an open-circuit voltage of 1.24 V, a short-circuit current density value of 6.18 mA cm-2, a fill factor of 47.12%, and a power conversion efficiency of about 3.61%. We believe that the obtained results contribute to the development of organic photovoltaic devices and to the understanding of the impact of sp2-bonded carbon therein.

Graphene nanoplatelet doping of P3HT:PCBM photoactive layer of bulk heterojunction organic solar cells for enhancing performance.

PubMed

Aïssa, Brahim; Nedil, Mourad; Kroeger, Jens; Ali, Adnan; Isaifan, Rima J; Essehli, Rachid; Mahmoud, Khaled A

2018-01-31

Hybrid organic photovoltaic (OPV) cells based on conjugated polymer photoactive materials are promising candidates for flexible, high-performance and low-cost energy sources owing to their inexpensive materials, cost-effective processing and ease of fabrication by simple solution processes. However, the modest PV performance obtained to date-in particular the low power conversion efficiency (PCE)-has impeded the large scale deployment of OPV cells. The low PCE in OPV solar cells is mainly attributed to the low carrier mobility, which is closely correlated to the transport diffusion length of the charge carriers within the photoactive layers. The 2D graphene material could be an excellent candidate for assisting charge transport improvement in the active layer of OPV cells, due to its huge carrier mobility, thermal and chemical stability, and its compatibility with the solution process. In this work, we report on the improvement of the optoelectronic properties and photovoltaic performance of graphene nanoplatelet (GNP)-doped P3HT:PCBM photoactive blended layers, integrated into a bulk heterojunction (BHJ) organic-photovoltaic-based device, using PEDOT:PSS on an ITO/glass substrate. First, the light absorption capacity was observed to increase with respect to the GNP content, while the photoluminescence showed clear quenching, indicating electron transfer between the graphene sheets and the polymeric matrix. Then, the incorporation of GNP into the BHJ active layer resulted in enhanced PV performance with respect to the reference cell, and the best PV performance was obtained with 3 wt.% of GNP loading, with an open-circuit voltage of 1.24 V, a short-circuit current density value of 6.18 mA cm -2 , a fill factor of 47.12%, and a power conversion efficiency of about 3.61%. We believe that the obtained results contribute to the development of organic photovoltaic devices and to the understanding of the impact of sp 2 -bonded carbon therein.

Graphene nanoplatelets doping of P3HT:PCBM photoactive layer of bulk heterojunction organic solar cells for enhancing performance.

PubMed

Aissa, Brahim; Nedil, Mourad; Kroeger, Jens; Ali, Adnan; Isaifan, Rima J; Essehli, Rachid; Mahmoud, Khaled

2018-01-09

Hybrid organic photovoltaic (OPV) cells based on conjugated polymers photoactive materials are promising candidates for flexible, high-performance and low-cost energy sources owing to their inexpensive materials, cost-effective processing, and ease of fabrication by simple solution processes. However, the modest PV performance obtained to date -in particular the low power conversion efficiency (PCE)- has impeded the large scale deployment of OPV cells. The low PCE in OPV solar cells has been mainly attributed to low carrier mobility, which is closely correlated to the transport diffusion length of the charge carriers within the photoactive layers. The 2D graphene material can be an excellent candidate for assisting the charge transport improvement in the active layer of OPV cells due to its huge carrier mobility, thermal and chemical stability, and its compatibility with the solution process. In this work, we report on the improvement of optoelectronic properties and photovoltaic performance of graphene nanoplatelets (GNP) doped P3HT:PCBM photoactive blended layers, integrated into a bulk heterojunction (BHJ) organic photovoltaic based device, using PEDOT:PSS on ITO/glass substrate. First, the light absorption capacity was observed to increase with respect to the GNP contents while the photoluminescence showed a clear quenching, indicating electrons transfer between the graphene sheets and the polymeric matrix. Then, the incorporation of GNP into the BHJ active layer has resulted in enhanced PV performance with respect to a reference cell, and the best PV performances were obtained with 3 wt. % of GNP loading, with an open-circuit voltage of 1.24 V, a short-circuit current density value of 6.18 mA/cm2, a fill factor of 47.12 %, and a power conversion efficiency of about 3.61 %. We believe that the obtained results contribute to the development of organic photovoltaic devices and to the understanding of the impact of sp2-bonded carbon therein. © 2018 IOP Publishing Ltd.

Performance Analysis and Discussion on the Thermoelectric Element Footprint for PV-TE Maximum Power Generation

NASA Astrophysics Data System (ADS)

Li, Guiqiang; Zhao, Xudong; Jin, Yi; Chen, Xiao; Ji, Jie; Shittu, Samson

2018-06-01

Geometrical optimisation is a valuable way to improve the efficiency of a thermoelectric element (TE). In a hybrid photovoltaic-thermoelectric (PV-TE) system, the photovoltaic (PV) and thermoelectric (TE) components have a relatively complex relationship; their individual effects mean that geometrical optimisation of the TE element alone may not be sufficient to optimize the entire PV-TE hybrid system. In this paper, we introduce a parametric optimisation of the geometry of the thermoelectric element footprint for a PV-TE system. A uni-couple TE model was built for the PV-TE using the finite element method and temperature-dependent thermoelectric material properties. Two types of PV cells were investigated in this paper and the performance of PV-TE with different lengths of TE elements and different footprint areas was analysed. The outcome showed that no matter the TE element's length and the footprint areas, the maximum power output occurs when A n /A p = 1. This finding is useful, as it provides a reference whenever PV-TE optimisation is investigated.

Felis catus papillomavirus types 1 and 4 are rarely present in neoplastic and inflammatory oral lesions of cats.

PubMed

Munday, John S; French, Adrienne F

2015-06-01

Oral squamous cell carcinomas (OSCCs) are common feline cancers. Why OSCCs are so common in cats is unknown; however, 25% of human OSCCs are caused by papillomaviruses (PVs). Two feline oral PVs (FcaPV-1 and 4) are recognized. As PVs are highly host and location specific, if PVs do cause feline OSCCs, FcaPV-1 and 4 are the most likely etiological agents. PCR primers specific for FcaPV-1 amplified DNA from 1 of 36 feline OSCCs and 1 of 16 inflammatory oral lesions. No DNA was amplified by primers specific for FcaPV-4. PV DNA was not amplified from any additional sample using consensus primers. No PV cytopathology was visible in the OSCC that contained FcaPV-1 DNA, but viral cytopathology was present in a focus of epithelial hyperplasia in the non-neoplastic sample. This study does not support a PV etiology of feline OSCCs, but shows that FcaPV-1 can asymptomatically infect the mouth of cats. Copyright © 2015 Elsevier Ltd. All rights reserved.

A MPPT Algorithm Based PV System Connected to Single Phase Voltage Controlled Grid

NASA Astrophysics Data System (ADS)

Sreekanth, G.; Narender Reddy, N.; Durga Prasad, A.; Nagendrababu, V.

2012-10-01

Future ancillary services provided by photovoltaic (PV) systems could facilitate their penetration in power systems. In addition, low-power PV systems can be designed to improve the power quality. This paper presents a single-phase PV systemthat provides grid voltage support and compensation of harmonic distortion at the point of common coupling thanks to a repetitive controller. The power provided by the PV panels is controlled by a Maximum Power Point Tracking algorithm based on the incremental conductance method specifically modified to control the phase of the PV inverter voltage. Simulation and experimental results validate the presented solution.

Multi-position photovoltaic assembly

DOEpatents

Dinwoodie, Thomas L.

2003-03-18

The invention is directed to a PV assembly, for use on a support surface, comprising a base, a PV module, a multi-position module support assembly, securing the module to the base at shipping and inclined-use angles, a deflector, a multi-position deflector support securing the deflector to the base at deflector shipping and deflector inclined-use angles, the module and deflector having opposed edges defining a gap therebetween. The invention permits transport of the PV assemblies in a relatively compact form, thus lowering shipping costs, while facilitating installation of the PV assemblies with the PV module at the proper inclination.

Life Cycle Analysis for the Feasibility of Photovoltaic System Application in Indonesia

NASA Astrophysics Data System (ADS)

Yudha, H. M.; Dewi, T.; Risma, P.; Oktarina, Y.

2018-03-01

Electricity has become the basic need for everyone, from industry to domestic. Today electricity source still depends heavily on fossil fuels that soon will be diminished from the earth in around 50 years. This condition demands us to find the renewable energy to support our everyday life. One of the famous renewable energy sources is from solar, harnessed by energy conversion device named solar cells. Countries like Indonesia are gifted with an abundance of sunlight all the yearlong. The application of solar cells with its photovoltaic (PV) technology harnesses the sunlight and converts it into electricity. Although this technology is emerging very fast, it still has some limitation due to the current PV technology, economic feasibility, and its environmental impacts. Life cycle assessment is the method to analyze and evaluate the sustainability of PV system and its environmental impact. This paper presents literature study of PV system from the cradle to grave, it begins with the material choices (from the first generation and the possibility of the fourth generation), manufacturing process, implementation, and ends it with the after-life effect of PV modules. The result of this study will be the insights look of the PV system application in Indonesia, from the best option of material choice, the best method of application, the energy payback time, and finally the possible after life recycle of PV materials.

US photovoltaic patents, 1951--1987

NASA Astrophysics Data System (ADS)

1988-09-01

This document contains 2195 U.S. patents on terrestrial photovoltaic (PV) power applications, including systems, components, and materials as well as manufacturing and support functions. The patent entries in this document were issued from 1951 through 1987; no patents were found in 1950. The entries were located by searching USPA, the data base of the U.S. Patent Office. The final search retrieved all patents under the class Batteries, Thermoelectric and Photoelectric, and the subclasses Photoelectric, Testing, and Applications. The search also located patents that contained the words photovoltaic(s) or solar cell(s) and their derivatives. A manual search of the patents in the Solar Energy Research Institute (SERI) patent file augmented the data base search. After the initial list was compiled, most of the patents on the following subjects were excluded: space photovoltaic technology, use of the photovoltaic effect for detectors, and subjects only peripherally concerned with photovoltaics. Some patents on these three subjects were included when it appeared that those inventions might be of use in terrwstrial PV power technologies.

Causal Evidence for the Role of Specific GABAergic Interneuron Types in Entorhinal Recruitment of Dentate Granule Cells

PubMed Central

Lee, Cheng-Ta; Kao, Min-Hua; Hou, Wen-Hsien; Wei, Yu-Ting; Chen, Chin-Lin; Lien, Cheng-Chang

2016-01-01

The dentate gyrus (DG) is the primary gate of the hippocampus and controls information flow from the cortex to the hippocampus proper. To maintain normal function, granule cells (GCs), the principal neurons in the DG, receive fine-tuned inhibition from local-circuit GABAergic inhibitory interneurons (INs). Abnormalities of GABAergic circuits in the DG are associated with several brain disorders, including epilepsy, autism, schizophrenia, and Alzheimer disease. Therefore, understanding the network mechanisms of inhibitory control of GCs is of functional and pathophysiological importance. GABAergic inhibitory INs are heterogeneous, but it is unclear how individual subtypes contribute to GC activity. Using cell-type-specific optogenetic perturbation, we investigated whether and how two major IN populations defined by parvalbumin (PV) and somatostatin (SST) expression, regulate GC input transformations. We showed that PV-expressing (PV+) INs, and not SST-expressing (SST+) INs, primarily suppress GC responses to single cortical stimulation. In addition, these two IN classes differentially regulate GC responses to θ and γ frequency inputs from the cortex. Notably, PV+ INs specifically control the onset of the spike series, whereas SST+ INs preferentially regulate the later spikes in the series. Together, PV+ and SST+ GABAergic INs engage differentially in GC input-output transformations in response to various activity patterns. PMID:27830729

Comparative evaluation of cell culture-adapted and chicken embryo-adapted fowl pox vaccine strains.

PubMed

Baxi, M K; Oberoi, M S

1999-01-01

Two types of vaccines, chicken embryo adapted (VacCE) and cell culture adapted (VacCC), were tested for their efficacy to elicite the immune response in birds vaccinated at 2 and 8 wk of age. The cell-mediated immune response studied by blastogenesis assay showed that birds vaccinated at the second week of age by both VacCE and VacCC vaccines had significant increase in T-lymphocyte count at 21 days postvaccination (PV) and 7 days postchallenge (PC), whereas in birds vaccinated at 8 wk of age, a significant increase was seen at 21 days PV and 7 days PC with the VacCC vaccine. The rise in passive hemagglutination titers was observed up to 21 days PV and 7 days PC in birds vaccinated at 2 wk of age. However, only the birds vaccinated with VacCC at 8 wk of age showed rise in titers at days 21 PV and 7 PC. Birds were challenged 90 days PV by scarification on the thigh region, and the birds vaccinated with VacCC showed 90% and 70% protection when vaccinated at 2 and 8 wk, respectively. The birds vaccinated with VacCE showed only 60% and 20% protection at the corresponding levels, respectively.

Atrophying pityriasis versicolor as an idiosyncratic T cell-mediated response to Malassezia: A case series.

PubMed

Levy, Jonathan Michael Stephen; Magro, Cynthia

2017-04-01

Atrophying pityriasis versicolor (PV), first described in 1971, is a rare variant in which lesions appear atrophic. We sought to determine the pathophysiology of atrophying PV. A retrospective chart review identified 6 cases of atrophying PV. In all cases, routine light microscopy, an elastic tissue stain, and immunohistochemical assessment for the expression of CD3, CD4, CD8, GATA3 and CXCR3 was performed. All cases demonstrated hyperkeratosis with intracorneal infiltration by pathogenic hyphal forms as well as epidermal attenuation and papillary dermal elastolysis. A supervening, mild-to-moderate, superficial lymphocytic infiltrate was noted and characterized by a focal CD8 + T cell-mediated interface dermatitis along with a mixed T-cell infiltrate composed of GATA3 + and CXCR3 + T cells. Small sample size and the loss of some patients to follow-up. Atrophying PV represents the sequelae of a mixed helper T-cell (T H 1 and T H 2) idiosyncratic immune response to Malassezia and can present as a protracted dermatosis that may clinically mimic an atypical lymphocytic infiltrate. T H 1 cytokines can recruit histiocytes, a source of elastases, and upregulate matrix metalloproteinase activity, which may contribute to epidermal atrophy. Copyright © 2016. Published by Elsevier Inc.

Populations of Xanthomonas citri pv. mangiferaeindicae from asymptomatic mango leaves are primarily endophytic.

PubMed

Pruvost, Olivier; Savelon, Caroline; Boyer, Claudine; Chiroleu, Frédéric; Gagnevin, Lionel; Jacques, Marie-Agnès

2009-07-01

Epiphytic survival of several Xanthomonas pathovars has been reported, but most studies failed to determine whether such populations were resident epiphytes, resulting from latent infections, or casual epiphytes. This study aimed at understanding the nature of Xanthomonas citri pv. mangiferaeindicae populations associated with asymptomatic leaves. When spray-inoculated on mango leaves cv. Maison Rouge, the pathogen multiplied markedly in association with juvenile leaves, but was most often detected as low population sizes (<1 x 10(3) cfu g(-1)) in association with mature leaves. Our results suggest a very low biological significance of biofilm-associated populations of X. citri pv. mangiferaeindicae, while saprophytic microbiota associated with mango leaves survived frequently as biofilms. A chloroform vapor-based disinfestation assay which kills cells specifically located on the leaf surface and not those located within the leaf mesophyll was developed. When applied to spray-inoculated leaves maintained under controlled environmental conditions, 155 out of the 168 analyzed datasets collected over three assessment dates for seven bacterial strains representative of the genetic diversity of the pathogen failed to demonstrate a significant X. citri pv. mangiferaeindicae population decrease on chloroform treated leaves up to 13 days after inoculation. We conclude that an efficient survival of X. citri pv. mangiferaeindicae present on mango leaf surfaces following a limited dissemination event is largely dependent on the availability of juvenile plant tissues. The bacterium gains access to protected sites (e.g., mesophyll) through stomata where it becomes endophytic and eventually causes disease. Chloroform vapor-based disinfestation assays should be useful for further studies aiming at evaluating survival sites of bacteria associated with the phyllosphere.

Intrinsic Defect Physics in Indium-based Lead-free Halide Double Perovskites.

PubMed

Xu, Jian; Liu, Jian-Bo; Liu, Bai-Xin; Huang, Bing

2017-09-21

Lead-free halide double perovskites (HDPs) are expected to be promising photovoltaic (PV) materials beyond organic-inorganic halide perovskite, which is hindered by its structural instability and toxicity. The defect- and stability-related properties of HDPs are critical for the use of HDPs as important PV absorbers, yet their reliability is still unclear. Taking Cs 2 AgInBr 6 as a representative, we have systemically investigated the defect properties of HDPs by theoretical calculations. First, we have determined the stable chemical potential regions to grow stoichiometric Cs 2 AgInBr 6 without structural decomposition. Second, we reveal that Ag-rich and Br-poor are the ideal chemical potential conditions to grow n-type Cs 2 AgInBr 6 with shallow defect levels. Third, we find the conductivity of Cs 2 AgInBr 6 can change from good n-type, to poorer n-type, to intrinsic semiconducting depending on the growth conditions. Our studies provided important guidance for experiments to fabricate Pb-free perovskite-based solar cell devices with superior PV performances.

A genetically engineered H5 protein expressed in insect cells confers protection against different clades of H5N1 highly pathogenic avian influenza viruses in chickens.

PubMed

Oliveira Cavalcanti, Marcia; Vaughn, Eric; Capua, Ilaria; Cattoli, Giovanni; Terregino, Calogero; Harder, Timm; Grund, Christian; Vega, Carlos; Robles, Francisco; Franco, Julio; Darji, Ayub; Arafa, Abdel-Satar; Mundt, Egbert

2017-04-01

The evolution of highly pathogenic H5N1 avian influenza viruses (HPAI-H5N1) has resulted in the appearance of a number of diverse groups of HPAI-H5N1 based on the presence of genetically similar clusters of their haemagglutinin sequences (clades). An H5 antigen encoded by a recombinant baculovirus and expressed in insect cells was used for oil-emulsion-based vaccine prototypes. In several experiments, vaccination was performed at 10 days of age, followed by challenge infection on day 21 post vaccination (PV) with HPAI-H5N1 clades 2.2, 2.2.1, and 2.3.2. A further challenge infection with HPAI-H5N1 clade 2.2.1 was performed at day 42 PV. High haemagglutination inhibition titres were observed for the recH5 vaccine antigen, and lower haemagglutination inhibition titres for the challenge virus antigens. Nevertheless, the rate of protection from mortality and clinical signs was 100% when challenged at 21 days PV and 42 days PV, indicating protection over the entire broiler chicken rearing period without a second vaccination. The unvaccinated control chickens mostly died between two and five days after challenge infection. A low level of viral RNA was detected by reverse transcription followed by a quantitative polymerase chain reaction in a limited number of birds for a short period after challenge infection, indicating a limited spread of HPAI-H5N1 at flock level. Furthermore, it was observed that the vaccine can be used in a differentiation infected from vaccinated animals (DIVA) approach, based on the detection of nucleoprotein antibodies in vaccinated/challenged chickens. The vaccine fulfilled all expectations of an inactivated vaccine after one vaccination against challenge with different clades of H5N1-HPAI and is suitable for a DIVA approach.

Distinctive CD8+ T cell and MHC class I signatures in polycythemia vera patients.

PubMed

Cardoso, Elsa M; Esgalhado, André J; Patrão, Luís; Santos, Mónica; Neves, Vasco Pinto; Martinez, Jorge; Patto, Maria Assunção Vaz; Silva, Helena; Arosa, Fernando A

2018-05-22

Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by overproduction of red blood cells. We have performed a comprehensive characterization of blood immune cells for expression of naïve and memory receptors as well as β 2 m-associated and β 2 m-free MHC class I heavy chains, also known as closed and open conformers, respectively, in PV patients and age-matched controls (CTR). We show that the peripheral CD3 + CD8 + T cell pool in PV patients is clearly divided into two discrete populations, a more granular CD3 + CD8 high T cell population enriched in effector-memory CD45RA + T cells (CD8 + TEMRA) when compared to CTR (P < 0.001), and a less granular CD3 + CD8 int T cell population that is completely absent in the CTR group (78 vs. 0%, P < 0.001) and is a mixture of naïve (CD8 + T N ) and CD8 + TEMRA cells expressing intermediate levels of CD28, i.e., CD3 + CD8 int CD28 int . While the percentage of CD3 + CD8 int TN cells correlated positively with the number of erythrocytes, the percentage of CD3 + CD8 int TEMRA correlated negatively with the number of platelets. Finally, we report that PV patients' lymphocytes and monocytes display lower levels of closed (W6/32 + ) MHC-I conformers at the cell surface while exhibiting increased amounts of open (HC-10 + ) MHC-I conformers. The implications of this distinctive immune signature are discussed.

Can Integrated Micro-Optical Concentrator Technology Revolutionize Flat-Plate Photovoltaic Solar Energy Harvesting?

NASA Astrophysics Data System (ADS)

Haney, Michael W.

2015-12-01

The economies-of-scale and enhanced performance of integrated micro-technologies have repeatedly delivered disruptive market impact. Examples range from microelectronics to displays to lighting. However, integrated micro-scale technologies have yet to be applied in a transformational way to solar photovoltaic panels. The recently announced Micro-scale Optimized Solar-cell Arrays with Integrated Concentration (MOSAIC) program aims to create a new paradigm in solar photovoltaic panel technology based on the incorporation of micro-concentrating photo-voltaic (μ-CPV) cells. As depicted in Figure 1, MOSAIC will integrate arrays of micro-optical concentrating elements and micro-scale PV elements to achieve the same aggregated collection area and high conversion efficiency of a conventional (i.e., macro-scale) CPV approach, but with the low profile and mass, and hopefully cost, of a conventional non-concentrated PV panel. The reduced size and weight, and enhanced wiring complexity, of the MOSAIC approach provide the opportunity to access the high-performance/low-cost region between the conventional CPV and flat-plate (1-sun) PV domains shown in Figure 2. Accessing this portion of the graph in Figure 2 will expand the geographic and market reach of flat-plate PV. This talk reviews the motivation and goals for the MOSAIC program. The diversity of the technical approaches to micro-concentration, embedded solar tracking, and hybrid direct/diffuse solar resource collection found in the MOSAIC portfolio of projects will also be highlighted.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yelundur, Vijay

Suniva, Inc., in collaboration with the University Center for Excellence in Photovoltaics (UCEP) at the Georgia Institute of Technology (GIT) proposed this comprehensive three year program to enable the development of an advanced high performance product that will help the US regain its competitive edge in PV. This project was designed to overcome cost and efficiency barriers through advances in PV science, technology innovation, low-cost manufacturing and full production of ~22.5% efficient n-type Si cells in Norcross, GA. At the heart of the project is the desire to complement the technology being developed concurrently under the Solarmat and ARPAe initiativesmore » to develop a differentiated product superior in both performance and cost effectiveness to the competing alternatives available on the market, and push towards achieving SunShot objectives while ensuring a sustainable business model based on US manufacturing. A significant reduction of the costs in modules produced today will need to combine reductions in wafer costs, cell processing costs as well as module fabrication costs while delivering a product that is not only more efficient under test conditions but also increases the energy yield in outdoor operations. This project will result in a differentiated high performance product and technology that is consistent with sustaining PV manufacturing in the US for a longer term and further highlights the need for continued support for developing the next generation concepts that can keep US manufacturing thriving to support the growing demand for PV in the US and consistent with the US government’s mandates for energy independence.« less

Design and optimization of cascaded DCG based holographic elements for spectrum-splitting PV systems

NASA Astrophysics Data System (ADS)

Wu, Yuechen; Chrysler, Benjamin; Pelaez, Silvana Ayala; Kostuk, Raymond K.

2017-09-01

In this work, the technique of designing and optimizing broadband volume transmission holograms using dichromate gelatin (DCG) is summarized for solar spectrum-splitting application. Spectrum splitting photovoltaic system uses a series of single bandgap PV cells that have different spectral conversion efficiency properties to more fully utilize the solar spectrum. In such a system, one or more high performance optical filters are usually required to split the solar spectrum and efficiently send them to the corresponding PV cells. An ideal spectral filter should have a rectangular shape with sharp transition wavelengths. DCG is a near ideal holographic material for solar applications as it can achieve high refractive index modulation, low absorption and scattering properties and long-term stability to solar exposure after sealing. In this research, a methodology of designing and modeling a transmission DCG hologram using coupled wave analysis for different PV bandgap combinations is described. To achieve a broad diffraction bandwidth and sharp cut-off wavelength, a cascaded structure of multiple thick holograms is described. A search algorithm is also developed to optimize both single and two-layer cascaded holographic spectrum splitters for the best bandgap combinations of two- and three-junction SSPV systems illuminated under the AM1.5 solar spectrum. The power conversion efficiencies of the optimized systems under the AM1.5 solar spectrum are then calculated using the detailed balance method, and shows an improvement compared with tandem structure.

Active optimal control strategies for increasing the efficiency of photovoltaic cells

NASA Astrophysics Data System (ADS)

Aljoaba, Sharif Zidan Ahmad

Energy consumption has increased drastically during the last century. Currently, the worldwide energy consumption is about 17.4 TW and is predicted to reach 25 TW by 2035. Solar energy has emerged as one of the potential renewable energy sources. Since its first physical recognition in 1887 by Adams and Day till nowadays, research in solar energy is continuously developing. This has lead to many achievements and milestones that introduced it as one of the most reliable and sustainable energy sources. Recently, the International Energy Agency declared that solar energy is predicted to be one of the major electricity production energy sources by 2035. Enhancing the efficiency and lifecycle of photovoltaic (PV) modules leads to significant cost reduction. Reducing the temperature of the PV module improves its efficiency and enhances its lifecycle. To better understand the PV module performance, it is important to study the interaction between the output power and the temperature. A model that is capable of predicting the PV module temperature and its effects on the output power considering the individual contribution of the solar spectrum wavelengths significantly advances the PV module edsigns toward higher efficiency. In this work, a thermoelectrical model is developed to predict the effects of the solar spectrum wavelengths on the PV module performance. The model is characterized and validated under real meteorological conditions where experimental temperature and output power of the PV module measurements are shown to agree with the predicted results. The model is used to validate the concept of active optical filtering. Since this model is wavelength-based, it is used to design an active optical filter for PV applications. Applying this filter to the PV module is expected to increase the output power of the module by filtering the spectrum wavelengths. The active filter performance is optimized, where different cutoff wavelengths are used to maximize the module output power. It is predicted that if the optimized active optical filter is applied to the PV module, the module efficiency is predicted to increase by about 1%. Different technologies are considered for physical implementation of the active optical filter.

Cellular and humoral immune responses against the Plasmodium vivax MSP-119 malaria vaccine candidate in individuals living in an endemic area in north-eastern Amazon region of Brazil

PubMed Central

2013-01-01

Background Plasmodium vivax merozoite surface protein-1 (MSP-1) is an antigen considered to be one of the leading malaria vaccine candidates. PvMSP-1 is highly immunogenic and evidences suggest that it is target for protective immunity against asexual blood stages of malaria parasites. Thus, this study aims to evaluate the acquired cellular and antibody immune responses against PvMSP-1 in individuals naturally exposed to malaria infections in a malaria-endemic area in the north-eastern Amazon region of Brazil. Methods The study was carried out in Paragominas, Pará State, in the Brazilian Amazon. Blood samples were collected from 35 individuals with uncomplicated malaria. Peripheral blood mononuclear cells were isolated and the cellular proliferation and activation was analysed in presence of 19 kDa fragment of MSP-1 (PvMSP-119) and Plasmodium falciparum PSS1 crude antigen. Antibodies IgE, IgM, IgG and IgG subclass and the levels of TNF, IFN-γ and IL-10 were measured by enzyme-linked immunosorbent assay. Results The prevalence of activated CD4+ was greater than CD8+ T cells, in both ex-vivo and in 96 h culture in presence of PvMSP-119 and PSS1 antigen. A low proliferative response against PvMSP-119 and PSS1 crude antigen after 96 h culture was observed. High plasmatic levels of IFN-γ and IL-10 as well as lower TNF levels were also detected in malaria patients. However, in the 96 h supernatant culture, the dynamics of cytokine responses differed from those depicted on plasma assays; in presence of PvMSP-119 stimulus, higher levels of TNF were noted in supernatant 96 h culture of malaria patient’s cells while low levels of IFN-γ and IL-10 were verified. High frequency of malaria patients presenting antibodies against PvMSP-119 was evidenced, regardless class or IgG subclass.PvMSP-119-induced antibodies were predominantly on non-cytophilic subclasses. Conclusions The results presented here shows that PvMSP-119 was able to induce a high cellular activation, leading to production of TNF and emphasizes the high immunogenicity of PvMSP-119 in naturally exposed individuals and, therefore, its potential as a malaria vaccine candidate. PMID:24041406

Microfabrication of microsystem-enabled photovoltaic (MEPV) cells

NASA Astrophysics Data System (ADS)

Nielson, Gregory N.; Okandan, Murat; Cruz-Campa, Jose L.; Resnick, Paul J.; Wanlass, Mark W.; Clews, Peggy J.; Pluym, Tammy C.; Sanchez, Carlos A.; Gupta, Vipin P.

2011-02-01

Microsystem-Enabled Photovoltaic (MEPV) cells allow solar PV systems to take advantage of scaling benefits that occur as solar cells are reduced in size. We have developed MEPV cells that are 5 to 20 microns thick and down to 250 microns across. We have developed and demonstrated crystalline silicon (c-Si) cells with solar conversion efficiencies of 14.9%, and gallium arsenide (GaAs) cells with a conversion efficiency of 11.36%. In pursuing this work, we have identified over twenty scaling benefits that reduce PV system cost, improve performance, or allow new functionality. To create these cells, we have combined microfabrication techniques from various microsystem technologies. We have focused our development efforts on creating a process flow that uses standard equipment and standard wafer thicknesses, allows all high-temperature processing to be performed prior to release, and allows the remaining post-release wafer to be reprocessed and reused. The c-Si cell junctions are created using a backside point-contact PV cell process. The GaAs cells have an epitaxially grown junction. Despite the horizontal junction, these cells also are backside contacted. We provide recent developments and details for all steps of the process including junction creation, surface passivation, metallization, and release.

Recombineering using RecET from Pseudomonas syringae

USDA-ARS?s Scientific Manuscript database

Here we report the identification of functions that promote genomic recombination of linear DNA introduced into Pseudomonas cells by electroporation. The genes encoding these functions were identified in Pseudomonas syringae pv. syringae B728a based on similarity to the lambda Red Exo/Beta and RecE...

Synergistic combination of valproic acid and oncolytic parvovirus H-1PV as a potential therapy against cervical and pancreatic carcinomas

PubMed Central

Li, Junwei; Bonifati, Serena; Hristov, Georgi; Marttila, Tiina; Valmary-Degano, Séverine; Stanzel, Sven; Schnölzer, Martina; Mougin, Christiane; Aprahamian, Marc; Grekova, Svitlana P; Raykov, Zahari; Rommelaere, Jean; Marchini, Antonio

2013-01-01

The rat parvovirus H-1PV has oncolytic and tumour-suppressive properties potentially exploitable in cancer therapy. This possibility is being explored and results are encouraging, but it is necessary to improve the oncotoxicity of the virus. Here we show that this can be achieved by co-treating cancer cells with H-1PV and histone deacetylase inhibitors (HDACIs) such as valproic acid (VPA). We demonstrate that these agents act synergistically to kill a range of human cervical carcinoma and pancreatic carcinoma cell lines by inducing oxidative stress, DNA damage and apoptosis. Strikingly, in rat and mouse xenograft models, H-1PV/VPA co-treatment strongly inhibits tumour growth promoting complete tumour remission in all co-treated animals. At the molecular level, we found acetylation of the parvovirus nonstructural protein NS1 at residues K85 and K257 to modulate NS1-mediated transcription and cytotoxicity, both of which are enhanced by VPA treatment. These results warrant clinical evaluation of H-1PV/VPA co-treatment against cervical and pancreatic ductal carcinomas. PMID:24092664

Earth abundant thin film technology for next generation photovoltaic modules

NASA Astrophysics Data System (ADS)

Alapatt, Githin Francis

With a cumulative generation capacity of over 100 GW, Photovoltaics (PV) technology is uniquely poised to become increasingly popular in the coming decades. Although, several breakthroughs have propelled PV technology, it accounts for only less than 1% of the energy produced worldwide. This aspect of the PV technology is primarily due to the somewhat high cost per watt, which is dependent on the efficiency of the PV cells as well as the cost of manufacturing and installing them. Currently, the efficiency of the PV conversion process is limited to about 25% for commercial terrestrial cells; improving this efficiency can increase the penetration of PV worldwide rapidly. A critical review of all possibilities pursued in the public domain reveals serious shortcomings and manufacturing issues. To make PV generated power a reality in every home, a Multi-Junction Multi-Terminal (MJMT) PV architecture can be employed combining silicon and another earth abundant material. However, forming electronic grade thin films of earth abundant materials is a non-trivial challenge; without solving this, it is impossible to increase the overall PV efficiency. Deposition of Copper (I) Oxide, an earth abundant semiconducting material, was conducted using an optimized Photo assisted Chemical Vapor Deposition process. X-Ray Diffraction, Ellipsometry, Transmission Electron Microscopy, and Profilometry revealed that the films composed of Cu2O of about 90 nm thickness and the grain size was as large as 600 nm. This result shows an improvement in material properties over previously grown thin films of Cu2O. Measurement of I-V characteristics of a diode structure composed of the Cu2O indicates an increase in On/Off ratio to 17,000 from the previous best value of 800. These results suggest that the electronic quality of the thin films deposited using our optimized process to be better than the results reported elsewhere. Using this optimized thin film forming technique, it is now possible to create a complete MJMT structure to improve the terrestrial commercial PV efficiency.

Variable responses of small and large human hepatocytes to hypoxia and hypoxia/reoxygenation (H-R).

PubMed

Bhogal, Ricky H; Weston, Christopher J; Curbishley, Stuart M; Bhatt, Anand N; Adams, David H; Afford, Simon C

2011-03-23

Hypoxia and hypoxia-reoxygenation (H-R) regulate human hepatocyte cell death by mediating the accumulation of reactive oxygen species (ROS). Hepatocytes within the liver are organised into peri-portal (PP) and peri-venous (PV) subpopulations. PP and PV hepatocytes differ in size and function. We investigated whether PP and PV human hepatocytes exhibit differential susceptibility to hypoxic stress. Isolated hepatocytes were used in an in vitro model of hypoxia and H-R. ROS production and cell death were assessed using flow cytometry. PV, and not PP hepatocytes, accumulate intracellular ROS in a mitochondrial dependent manner during hypoxia and H-R. This increased ROS regulates hepatocyte apoptosis and necrosis via a mitochondrial pathway. These findings have implications on the understanding of liver injury and application of potential therapeutic strategies. Copyright © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Enhanced model of photovoltaic cell/panel/array considering the direct and reverse modes

NASA Astrophysics Data System (ADS)

Zegaoui, Abdallah; Boutoubat, Mohamed; Sawicki, Jean-Paul; Kessaissia, Fatma Zohra; Djahbar, Abdelkader; Aillerie, Michel

2018-05-01

This paper presents an improved generalized physical model for photovoltaic, PV cells, panels and arrays taking into account the behavior of these devices when considering their biasing existing in direct and reverse modes. Existing PV physical models generally are very efficient for simulating influence of irradiation changes on the short circuit current but they could not visualize the influences of temperature changes. The Enhanced Direct and Reverse Mode model, named EDRM model, enlightens the influence on the short-circuit current of both temperature and irradiation in the reverse mode of the considered PV devices. Due to its easy implementation, the proposed model can be a useful power tool for the development of new photovoltaic systems taking into account and in a more exhaustive manner, environmental conditions. The developed model was tested on a marketed PV panel and it gives a satisfactory results compared with parameters given in the manufacturer datasheet.

A disynaptic feedback network activated by experience promotes the integration of new granule cells.

PubMed

Alvarez, Diego D; Giacomini, Damiana; Yang, Sung Min; Trinchero, Mariela F; Temprana, Silvio G; Büttner, Karina A; Beltramone, Natalia; Schinder, Alejandro F

2016-10-28

Experience shapes the development and connectivity of adult-born granule cells (GCs) through mechanisms that are poorly understood. We examined the remodeling of dentate gyrus microcircuits in mice in an enriched environment (EE). Short exposure to EE during early development of new GCs accelerated their functional integration. This effect was mimicked by in vivo chemogenetic activation of a limited population of mature GCs. Slice recordings showed that mature GCs recruit parvalbumin γ-aminobutyric acid-releasing interneurons (PV-INs) that feed back onto developing GCs. Accordingly, chemogenetic stimulation of PV-INs or direct depolarization of developing GCs accelerated GC integration, whereas inactivation of PV-INs prevented the effects of EE. Our results reveal a mechanism for dynamic remodeling in which experience activates dentate networks that "prime" young GCs through a disynaptic feedback loop mediated by PV-INs. Copyright © 2016, American Association for the Advancement of Science.

Direct evidence for activated CD8+ T cell transmigration across portal vein endothelial cells in liver graft rejection.

PubMed

Kariya, Taro; Ueta, Hisashi; Xu, Xue-Dong; Koga, Daisuke; Ezaki, Taichi; Yu, Enqiao; Kusumi, Satoshi; Kitazawa, Yusuke; Sawanobori, Yasushi; Ushiki, Tatsuo; Issekutz, Thomas; Matsuno, Kenjiro

2016-10-01

Lymphocyte recruitment into the portal tract is crucial not only for homeostatic immune surveillance but also for many liver diseases. However, the exact route of entry for lymphocytes into portal tract is still obscure. We investigated this question using a rat hepatic allograft rejection model. A migration route was analyzed by immunohistological methods including a recently developed scanning electron microscopy method. Transmigration-associated molecules such as selectins, integrins, and chemokines and their receptors expressed by hepatic vessels and recruited T-cells were analyzed by immunohistochemistry and flow cytometry. The immunoelectron microscopic analysis clearly showed CD8β(+) cells passing through the portal vein (PV) endothelia. Furthermore, the migrating pathway seemed to pass through the endothelial cell body. Local vascular cell adhesion molecule-1 (VCAM-1) expression was induced in PV endothelial cells from day 2 after liver transplantation. Although intercellular adhesion molecule-1 (ICAM-1) expression was also upregulated, it was restricted to sinusoidal endothelia. Recipient T-cells in the graft perfusate were CD25(+)CD44(+)ICAM-1(+)CXCR3(+)CCR5(-) and upregulated α4β1 or αLβ2 integrins. Immunohistochemistry showed the expression of CXCL10 in donor MHCII(high) cells in the portal tract as well as endothelial walls of PV. We show for the first time direct evidence of T-cell transmigration across PV endothelial cells during hepatic allograft rejection. Interactions between VCAM-1 on endothelia and α4β1 integrin on recipient effector T-cells putatively play critical roles in adhesion and transmigration through endothelia. A chemokine axis of CXCL10 and CXCR3 also may be involved.

Cost Estimates Of Concentrated Photovoltaic Heat Sink Production

DTIC Science & Technology

2016-06-01

steady year-round sunshine and in many cases high levels of direct normal irradiance (DNI). Beyond traditional PV , some climates favor rooftop solar ...water heating, but the majority of installed solar systems, are PV (EIA, 2015). Solar power generation has great benefits for the DON considering the...systems concentrate and focus sunlight onto a smaller focal point in order to take advantage of the highly efficient solar cells. Generally, PV

Host cell subversion by Toxoplasma GRA16, an exported dense granule protein that targets the host cell nucleus and alters gene expression.

PubMed

Bougdour, Alexandre; Durandau, Eric; Brenier-Pinchart, Marie-Pierre; Ortet, Philippe; Barakat, Mohamed; Kieffer, Sylvie; Curt-Varesano, Aurélie; Curt-Bertini, Rose-Laurence; Bastien, Olivier; Coute, Yohann; Pelloux, Hervé; Hakimi, Mohamed-Ali

2013-04-17

After invading host cells, Toxoplasma gondii multiplies within a parasitophorous vacuole (PV) that is maintained by parasite proteins secreted from organelles called dense granules. Most dense granule proteins remain within the PV, and few are known to access the host cell cytosol. We identify GRA16 as a dense granule protein that is exported through the PV membrane and reaches the host cell nucleus, where it positively modulates genes involved in cell-cycle progression and the p53 tumor suppressor pathway. GRA16 binds two host enzymes, the deubiquitinase HAUSP and PP2A phosphatase, which exert several functions, including regulation of p53 and the cell cycle. GRA16 alters p53 levels in a HAUSP-dependent manner and induces nuclear translocation of the PP2A holoenzyme. Additionally, certain GRA16-deficient strains exhibit attenuated virulence, indicating the importance of these host alterations in pathogenesis. Therefore, GRA16 represents a potentially emerging subfamily of exported dense granule proteins that modulate host function. Copyright © 2013 Elsevier Inc. All rights reserved.

Multi-parameter approach to evaluate the timing of memory status after 17DD-YF primary vaccination.

PubMed

Costa-Pereira, Christiane; Campi-Azevedo, Ana Carolina; Coelho-Dos-Reis, Jordana Grazziela; Peruhype-Magalhães, Vanessa; Araújo, Márcio Sobreira Silva; do Vale Antonelli, Lis Ribeiro; Fonseca, Cristina Toscano; Lemos, Jandira Aparecida; Malaquias, Luiz Cosme Cote; de Souza Gomes, Matheus; Rodrigues Amaral, Laurence; Rios, Maria; Chancey, Caren; Persi, Harold Richard; Pereira, Jorge Marcelo; de Sousa Maia, Maria de Lourdes; Freire, Marcos da Silva; Martins, Reinaldo de Menezes; Homma, Akira; Simões, Marisol; Yamamura, Anna Yoshida; Farias, Roberto Henrique Guedes; Romano, Alessandro Pecego Martins; Domingues, Carla Magda; Tauil, Pedro Luiz; Vasconcelos, Pedro Fernando Costa; Caldas, Iramaya Rodrigues; Camacho, Luiz Antônio; Teixeira-Carvalho, Andrea; Martins-Filho, Olindo Assis

2018-06-01

In this investigation, machine-enhanced techniques were applied to bring about scientific insights to identify a minimum set of phenotypic/functional memory-related biomarkers for post-vaccination follow-up upon yellow fever (YF) vaccination. For this purpose, memory status of circulating T-cells (Naïve/early-effector/Central-Memory/Effector-Memory) and B-cells (Naïve/non-Classical-Memory/Classical-Memory) along with the cytokine profile (IFN/TNF/IL-5/IL-10) were monitored before-NV(day0) and at distinct time-points after 17DD-YF primary vaccination-PV(day30-45); PV(year1-9) and PV(year10-11). A set of biomarkers (eEfCD4; EMCD4; CMCD19; EMCD8; IFNCD4; IL-5CD8; TNFCD4; IFNCD8; TNFCD8; IL-5CD19; IL-5CD4) were observed in PV(day30-45), but not in NV(day0), with most of them still observed in PV(year1-9). Deficiencies of phenotypic/functional biomarkers were observed in NV(day0), while total lack of memory-related attributes was observed in PV(year10-11), regardless of the age at primary vaccination. Venn-diagram analysis pre-selected 10 attributes (eEfCD4, EMCD4, CMCD19, EMCD8, IFNCD4, IL-5CD8, TNFCD4, IFNCD8, TNFCD8 and IL-5CD4), of which the overall mean presented moderate accuracy to discriminate PV(day30-45)&PV(year1-9) from NV(day0)&PV(year10-11). Multi-parameter approaches and decision-tree algorithms defined the EMCD8 and IL-5CD4 attributes as the top-two predictors with moderated performance. Together with the PRNT titers, the top-two biomarkers led to a resultant memory status observed in 80% and 51% of volunteers in PV(day30-45) and PV(year1-9), contrasting with 0% and 29% found in NV(day0) and PV(year10-11), respectively. The deficiency of memory-related attributes observed at PV(year10-11) underscores the conspicuous time-dependent decrease of resultant memory following17DD-YF primary vaccination that could be useful to monitor potential correlates of protection in areas under risk of YF transmission.

Multi-parameter approach to evaluate the timing of memory status after 17DD-YF primary vaccination

PubMed Central

Costa-Pereira, Christiane; Campi-Azevedo, Ana Carolina; Coelho-dos-Reis, Jordana Grazziela; Peruhype-Magalhães, Vanessa; Araújo, Márcio Sobreira Silva; do Vale Antonelli, Lis Ribeiro; Fonseca, Cristina Toscano; Lemos, Jandira Aparecida; Malaquias, Luiz Cosme Cote; de Souza Gomes, Matheus; Rodrigues Amaral, Laurence; Rios, Maria; Chancey, Caren; Persi, Harold Richard; Pereira, Jorge Marcelo; de Sousa Maia, Maria de Lourdes; Freire, Marcos da Silva; Martins, Reinaldo de Menezes; Homma, Akira; Simões, Marisol; Yamamura, Anna Yoshida; Farias, Roberto Henrique Guedes; Romano, Alessandro Pecego Martins; Domingues, Carla Magda; Tauil, Pedro Luiz; Vasconcelos, Pedro Fernando Costa; Caldas, Iramaya Rodrigues; Camacho, Luiz Antônio; Teixeira-Carvalho, Andrea; Martins-Filho, Olindo Assis

2018-01-01

In this investigation, machine-enhanced techniques were applied to bring about scientific insights to identify a minimum set of phenotypic/functional memory-related biomarkers for post-vaccination follow-up upon yellow fever (YF) vaccination. For this purpose, memory status of circulating T-cells (Naïve/early-effector/Central-Memory/Effector-Memory) and B-cells (Naïve/non-Classical-Memory/Classical-Memory) along with the cytokine profile (IFN/TNF/IL-5/IL-10) were monitored before-NV(day0) and at distinct time-points after 17DD-YF primary vaccination—PV(day30-45); PV(year1-9) and PV(year10-11). A set of biomarkers (eEfCD4; EMCD4; CMCD19; EMCD8; IFNCD4; IL-5CD8; TNFCD4; IFNCD8; TNFCD8; IL-5CD19; IL-5CD4) were observed in PV(day30-45), but not in NV(day0), with most of them still observed in PV(year1-9). Deficiencies of phenotypic/functional biomarkers were observed in NV(day0), while total lack of memory-related attributes was observed in PV(year10-11), regardless of the age at primary vaccination. Venn-diagram analysis pre-selected 10 attributes (eEfCD4, EMCD4, CMCD19, EMCD8, IFNCD4, IL-5CD8, TNFCD4, IFNCD8, TNFCD8 and IL-5CD4), of which the overall mean presented moderate accuracy to discriminate PV(day30-45)&PV(year1-9) from NV(day0)&PV(year10-11). Multi-parameter approaches and decision-tree algorithms defined the EMCD8 and IL-5CD4 attributes as the top-two predictors with moderated performance. Together with the PRNT titers, the top-two biomarkers led to a resultant memory status observed in 80% and 51% of volunteers in PV(day30-45) and PV(year1-9), contrasting with 0% and 29% found in NV(day0) and PV(year10-11), respectively. The deficiency of memory-related attributes observed at PV(year10-11) underscores the conspicuous time-dependent decrease of resultant memory following17DD-YF primary vaccination that could be useful to monitor potential correlates of protection in areas under risk of YF transmission. PMID:29879134

Some tests of flat plate photovoltaic module cell temperatures in simulated field conditions

NASA Technical Reports Server (NTRS)

Griffith, J. S.; Rathod, M. S.; Paslaski, J.

1981-01-01

The nominal operating cell temperature (NOCT) of solar photovoltaic (PV) modules is an important characteristic. Typically, the power output of a PV module decreases 0.5% per deg C rise in cell temperature. Several tests were run with artificial sun and wind to study the parametric dependencies of cell temperature on wind speed and direction and ambient temperature. It was found that the cell temperature is extremely sensitive to wind speed, moderately so to wind direction and rather insensitive to ambient temperature. Several suggestions are made to obtain data more typical of field conditions.

On-Orbit Measurement of Next Generation Space Solar Cell Technology on the International Space Station

NASA Technical Reports Server (NTRS)

Wolford, David S.; Myers, Matthew G.; Prokop, Norman F.; Krasowski, Michael J.; Parker, David S.; Cassidy, Justin C.; Davies, William E.; Vorreiter, Janelle O.; Piszczor, Michael F.; McNatt, Jeremiah S.

2014-01-01

On-orbit measurements of new photovoltaic (PV) technologies for space power are an essential step in the development and qualification of advanced solar cells. NASA Glenn Research Center will fly and measure several solar cells attached to NASA Goddards Robotic Refueling Mission (RRM), expected to be launched in 2014. Industry and government partners have provided advanced PV devices for evaluation of performance and environmental durability. The experiment is completely self-contained, providing its own power and internal data storage. Several new cell technologies including Inverted Metamorphic Multi-junction and four-junction cells will be tested.

Switchgrass (Panicum virgatum L.) promoters for green tissue-specific expression of the MYB4 transcription factor for reduced-recalcitrance transgenic switchgrass

DOE PAGES

Liu, Wusheng; Mazarei, Mitra; Ye, Rongjian; ...

2018-04-24

Genetic engineering of switchgrass (Panicum virgatum L.) for reduced cell wall recalcitrance and improved biofuel production has been a long pursued goal. Up to now, constitutive promoters have been used to direct the expression of cell wall biosynthesis genes toward attaining that goal. While generally sufficient to gauge a transgene's effects in the heterologous host, constitutive overexpression often leads to undesirable plant phenotypic effects. Green tissue-specific promoters from switchgrass are potentially valuable to directly alter cell wall traits exclusively in harvestable aboveground biomass while not changing root phenotypes. We identified and functionally characterized three switchgrass green tissue-specific promoters and assessedmore » marker gene expression patterns and intensity in stably transformed rice (Oryza sativa L.), and then used them to direct the expression of the switchgrass MYB4 (PvMYB4) transcription factor gene in transgenic switchgrass to endow reduced recalcitrance in aboveground biomass. These promoters correspond to photosynthesis-related light-harvesting complex II chlorophyll-a/b binding gene (PvLhcb), phosphoenolpyruvate carboxylase (PvPEPC), and the photosystem II 10 kDa R subunit (PvPsbR). Real-time RT-PCR analysis detected their strong expression in the aboveground tissues including leaf blades, leaf sheaths, internodes, inflorescences, and nodes of switchgrass, which was tightly up-regulated by light. Stable transgenic rice expressing the GUS reporter under the control of each promoter (756-2005 bp in length) further confirmed their strong expression patterns in leaves and stems. With the exception of the serial promoter deletions of PvLhcb, all GUS marker patterns under the control of each 5'-end serial promoter deletion were not different from that conveyed by their respective promoters. All of the shortest promoter fragments (199-275 bp in length) conveyed strong green tissue-specific GUS expression in transgenic rice. PvMYB4 is a master repressor of lignin biosynthesis. The green tissue-specific expression of PvMYB4 via each promoter in transgenic switchgrass led to significant gains in saccharification efficiency, decreased lignin, and decreased S/G lignin ratios. In contrast to constitutive overexpression of PvMYB4, which negatively impacts switchgrass root growth, plant growth was not compromised in green tissue-expressed PvMYB4 switchgrass plants in the current study. Each of the newly described green tissue-specific promoters from switchgrass has utility to change cell wall biosynthesis exclusively in aboveground harvestable biomass without altering root systems. The truncated green tissue promoters are very short and should be useful for targeted expression in a number of monocots to improve shoot traits while restricting gene expression from roots. Green tissue-specific expression of PvMYB4 is an effective strategy for improvement of transgenic feedstocks.« less

Switchgrass (Panicum virgatum L.) promoters for green tissue-specific expression of the MYB4 transcription factor for reduced-recalcitrance transgenic switchgrass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Wusheng; Mazarei, Mitra; Ye, Rongjian

Genetic engineering of switchgrass (Panicum virgatum L.) for reduced cell wall recalcitrance and improved biofuel production has been a long pursued goal. Up to now, constitutive promoters have been used to direct the expression of cell wall biosynthesis genes toward attaining that goal. While generally sufficient to gauge a transgene's effects in the heterologous host, constitutive overexpression often leads to undesirable plant phenotypic effects. Green tissue-specific promoters from switchgrass are potentially valuable to directly alter cell wall traits exclusively in harvestable aboveground biomass while not changing root phenotypes. We identified and functionally characterized three switchgrass green tissue-specific promoters and assessedmore » marker gene expression patterns and intensity in stably transformed rice (Oryza sativa L.), and then used them to direct the expression of the switchgrass MYB4 (PvMYB4) transcription factor gene in transgenic switchgrass to endow reduced recalcitrance in aboveground biomass. These promoters correspond to photosynthesis-related light-harvesting complex II chlorophyll-a/b binding gene (PvLhcb), phosphoenolpyruvate carboxylase (PvPEPC), and the photosystem II 10 kDa R subunit (PvPsbR). Real-time RT-PCR analysis detected their strong expression in the aboveground tissues including leaf blades, leaf sheaths, internodes, inflorescences, and nodes of switchgrass, which was tightly up-regulated by light. Stable transgenic rice expressing the GUS reporter under the control of each promoter (756-2005 bp in length) further confirmed their strong expression patterns in leaves and stems. With the exception of the serial promoter deletions of PvLhcb, all GUS marker patterns under the control of each 5'-end serial promoter deletion were not different from that conveyed by their respective promoters. All of the shortest promoter fragments (199-275 bp in length) conveyed strong green tissue-specific GUS expression in transgenic rice. PvMYB4 is a master repressor of lignin biosynthesis. The green tissue-specific expression of PvMYB4 via each promoter in transgenic switchgrass led to significant gains in saccharification efficiency, decreased lignin, and decreased S/G lignin ratios. In contrast to constitutive overexpression of PvMYB4, which negatively impacts switchgrass root growth, plant growth was not compromised in green tissue-expressed PvMYB4 switchgrass plants in the current study. Each of the newly described green tissue-specific promoters from switchgrass has utility to change cell wall biosynthesis exclusively in aboveground harvestable biomass without altering root systems. The truncated green tissue promoters are very short and should be useful for targeted expression in a number of monocots to improve shoot traits while restricting gene expression from roots. Green tissue-specific expression of PvMYB4 is an effective strategy for improvement of transgenic feedstocks.« less

Fluorescence and confocal imaging of mammalian cells using conjugated oligoelectrolytes with phenylenevinylene core

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milczarek, Justyna; Pawlowska, Roza; Zurawinski, Remigiusz

Over the last few years, considerable efforts are taken, in order to find a molecular fluorescent probe fulfilling their applicability requirements. Due to a good optical properties and affinity to biological structures conjugated oligoelectrolytes (COEs) can be considered as a promising dyes for application in fluorescence-based bioimaging. In this work, we synthetized COEs with phenylenevinylene core (PV-COEs) and applied as fluorescent membranous-specific probes. Cytotoxicity effects of each COE were probed on cancerous and non-cancerous cell types and little to no toxicity effects were observed at the high range of concentrations. The intensity of cell fluorescence following the COE staining wasmore » determined by the photoluminescence analysis and fluorescence activated cell sorting method (FACS). Intercalation of tested COEs into mammalian cell membranes was revealed by fluorescent and confocal microscopy colocalization with commercial dyes specific for cellular structures including mitochondria, Golgi apparatus and endoplasmic reticulum. The phenylenevinylene conjugated oligoelectrolytes have been found to be suitable for fluorescent bioimaging of mammalian cells and membrane-rich organelles. Due to their water solubility coupled with spontaneous intercalation into cells, favorable photophysical features, ease of cell staining, low cytotoxicity and selectivity for membranous structures, PV-COEs can be applied as markers for fluorescence imaging of a variety of cell types.« less

Photovoltaic electricity generation: Value for residential and commercial sectors

NASA Astrophysics Data System (ADS)

Bhattacharjee, Ujjwal

The photovoltaic (PV) industry in the US has seen an upsurge in recent years, and PV holds great promise as a renewable technology with no greenhouse gas emissions with its use. We aim to assess the value of PV based electricity for users in the residential and commercial sectors focusing on the financial impacts it has, which may not be greatly recognized. Specifically, we pursue two goals. First, the emerging 'renewable portfolio standard (RPS)' adopted in several states in the country has been a driving force for large scale PV deployment, but financial incentives offered to PV in different RPS states differ considerably. We use life cycle cost model to estimate the cost of PV based electricity for thirty-two RPS states in the country. Results indicate that the levelized cost of PV electricity is high (40 to 60 Cents/kWh). When the contribution of the financial incentives (along with the cost of energy saved) is taken into account, the cost of PV based electricity is negative in some RPS states such as California, New Jersey, New York, while for most of the RPS states the cost of PV electricity continues to remain high. In addition, the states with negative or low cost of PV electricity have been driving the PV diffusion in the residential sector. Therefore, a need to adjust the financial incentive structure in different RPS states is recommended for homogenous development of the residential PV market in the country. Second, we assess the value of the PV in reducing the highest peak load demand in commercial buildings and hence the high value demand charge. The Time-of-Use (TOU) based electricity tariff is widely used by electric utilities in the commercial sector. Energy and peak load are two important facets of the TOU tariff regime. Tools are well established to estimate the energy contribution from a PV system (installed in a commercial building), but not power output on a short time interval. A joint conditional probability model has been developed that enables estimation of the PV contribution towards the peak load reduction for a given high building load. Results indicate a significant cost saving (15% to 40%) with application of the model. This will encourage commercial entities (building owners) to adopt PV as a distributed energy source. The tool would be useful for energy modelers and green building architects as it will enable them to estimate cost savings due to PV deployment in commercial buildings. Moreover, the model tested for three different commercial buildings indicates that school buildings show the best promise for PV deployment followed, respectively, by office buildings and manufacturing facilities. This will help PV incentive programs in the country to use resources effectively to enhance the diffusion of PV in the commercial sector.

[Role of the National Poliovirus Laboratory for the Program of eradication and poliomyelitis surveillance].

PubMed

Trallero, Gloria; Cabrerizo, María; Avellón, Ana

2013-01-01

The Spanish acute flaccid paralysis surveillance network is coordinated by the National Poliovirus Laboratory (NPL), which, since 1998, carries out polioviruses (PV) and other enteroviruses detected characterization by cell culture and molecular techniques. A total of 110,725 (70046+40679) samples were studied between 1998-2012 and enteroviruses were detected in 8% of these. Among these enteroviruses 241 PV were characterized as PV Sabin-like, except samples belong to an imported poliomyelitis case, all of which were characterised as vaccine derived PV type 2. The NPL has carried out the serotyping and the intratypic differentiation of all the isolated PV in Spain of any syndrome. It is shown that wild PV has not circulated in our country during the 15 years studied and that has led to the signing of the Act of the "eradication of poliomyelitis in Spain" by WHO in 2001, and the /"certification of the eradication of wild PV free for European countries" on 21 June 2002. Currently only 3 countries have endemic transmission of wild PV (Pakistan, Afghanistan and Nigeria). Until a complete worldwide eradication, was achieved, Spain will actively continue to participate in the maintenance of the poliomyelitis eradication infrastructure by monitoring and vaccination as well as the wild PV containment plan to avoid the spread of wild PV.

Power Generation Potential and Cost of a Roof Top Solar PV System in Kathmandu, Nepal

NASA Astrophysics Data System (ADS)

Sanjel, N.; Zhand, A.

2017-12-01

The paper presents a comparative study of the 3 most used solar PV module technologies in Nepal, which are Si-mono-crystalline, Si-poly-crystalline and Si-amorphous. The aim of the paper is to present and discuss the recorded Global Solar Radiation, received in the Kathmandu valley by three different, Si-mono-crystalline, Si-poly-crystalline and Si-amorphous calibrated solar cell pyranometers and to propose the best-suited solar PV module technology for roof top solar PV systems inside the Kathmandu valley. Data recorded over the course of seven months, thus covering most of the seasonal meteorological conditions determining Kathmandu valley's global solar radiation reception are presented. The results indicate that the Si-amorphous pyranometer captured 1.56% more global solar radiation than the Si-mono-crystalline and 18.4% more than Si-poly-crystalline pyranometer over the course of seven months. Among the three pyranometer technologies the maximum and minimum cell temperature was measured by the Si-mono-crystalline pyranometer. Following the technical data and discussion, an economical analysis, using the versatile software tool PVSYST V5.01is used to calculate the life cycle costs of a 1kW roof top solar PV RAPS system, with battery storage, and a 1kW roof top solar PV grid connected system with no energy storage facility, through simulations, using average recorded global solar radiation data for the KTM valley and investigated market values for each solar PV module and peripheral equipment costs.

Simulation study of air and water cooled photovoltaic panel using ANSYS

NASA Astrophysics Data System (ADS)

Syafiqah, Z.; Amin, N. A. M.; Irwan, Y. M.; Majid, M. S. A.; Aziz, N. A.

2017-10-01

Demand for alternative energy is growing due to decrease of fossil fuels sources. One of the promising and popular renewable energy technology is a photovoltaic (PV) technology. During the actual operation of PV cells, only around 15% of solar irradiance is converted to electricity, while the rest is converted into heat. The electrical efficiency decreases with the increment in PV panel’s temperature. This electrical energy is referring to the open-circuit voltage (Voc), short-circuit current (Isc) and output power generate. This paper examines and discusses the PV panel with water and air cooling system. The air cooling system was installed at the back of PV panel while water cooling system at front surface. The analyses of both cooling systems were done by using ANSYS CFX and PSPICE software. The highest temperature of PV panel without cooling system is 66.3 °C. There is a decrement of 19.2% and 53.2% in temperature with the air and water cooling system applied to PV panel.

Elevated serum erythropoietin in a patient with polycythaemia vera presenting with Budd-Chiari syndrome

PubMed Central

Jones, Catherine; Levy, Yair; Tong, Alex W

2014-01-01

Polycythaemia vera (PV) is a clonal disorder of bone marrow stem cells characterised by erythrocytosis. Diagnosis of PV requires exclusion of secondary causes of polycythaemia. It has been held that an elevated erythropoietin (Epo) level strongly indicates secondary erythrocytosis and excludes PV diagnosis, to the extent that the reduced serum Epo level is currently listed as a minor criterion in the WHO classification scheme for PV. However, patients with PV who co-present with Budd-Chiari syndrome have been documented with elevated serum Epo levels. For these patients, identification of the Janus kinase 2 (JAK2) V617F point mutation along with the transient nature of the Epo elevation provides certainty of PV diagnosis, as illustrated by the proband. In this case report, the patient's positive response to cytoreductive therapy (hydroxyurea 500 mg daily) and phlebotomy (750 mL over three phlebotomies) further supports validity of PV diagnosis with elevated Epo. The patient remains on rivaroxaban (Xarelto) for treatment of her portal vein thrombosis. PMID:25452296

Numerical investigation of the thermal and electrical performances for combined solar photovoltaic/thermal (PV/T) modules based on internally extruded fin flow channel

NASA Astrophysics Data System (ADS)

Deng, Y. C.; Li, Q. P.; Wang, G. J.

2017-11-01

A solar photovoltaic/thermal (PV/T) module based on internally extruded fin flow channel was investigated numerically in this paper. First of all, the structures of the thin plate heat exchanger and the PV/T module were presented. Then, a numerical model of the PV/T module considering solar irradiation, fluid flow and heat transfer was developed to analyze the performance of the module. Finally, the steady electrical and thermal efficiencies of the PV/T module at different inlet water temperatures and mass flow rates were achieved. These numerical results supply theory basis for practical application of the PV/T module.

Xanthomonas filamentous hemagglutinin-like protein Fha1 interacts with pepper hypersensitive-induced reaction protein CaHIR1 and functions as a virulence factor in host plants.

PubMed

Choi, Hyong Woo; Kim, Dae Sung; Kim, Nak Hyun; Jung, Ho Won; Ham, Jong Hyun; Hwang, Byung Kook

2013-12-01

Pathogens have evolved a variety of virulence factors to infect host plants successfully. We previously identified the pepper plasma-membrane-resident hypersensitive-induced reaction protein (CaHIR1) as a regulator of plant disease- and immunity-associated cell death. Here, we identified the small filamentous hemagglutinin-like protein (Fha1) of Xanthomonas campestris pv. vesicatoria as an interacting partner of CaHIR1 using yeast two-hybrid screening. Coimmunoprecipitation and bimolecular fluorescence complementation experiments revealed that Fha1 specifically interacts with CaHIR1 in planta. The endocytic tracker FM4-64 staining showed that the CaHIR1-Fha1 complex localizes in the endocytic vesicle-like structure. The X. campestris pv. vesicatoria Δfha1 mutant strain exhibited significantly increased surface adherence but reduced swarming motility. Mutation of fha1 inhibited the growth of X. campestris pv. vesicatoria and X. campestris pv. vesicatoria ΔavrBsT in tomato and pepper leaves, respectively, suggesting that Fha1 acts as a virulence factor in host plants. Transient expression of fha1 and also infiltration with purified Fha1 proteins induced disease-associated cell death response through the interaction with CaHIR1 and suppressed the expression of pathogenesis-related (PR) genes. Silencing of CaHIR1 in pepper significantly reduced ΔavrBsT growth and Fha1-triggered susceptibility cell death. Overexpression of fha1 in Arabidopsis retarded plant growth and triggered disease-associated cell death, resulting in altered disease susceptibility. Taken together, these results suggest that the X. campestris pv. vesicatoria virulence factor Fha1 interacts with CaHIR1, induces susceptibility cell death, and suppresses PR gene expression in host plants.

A power pack based on organometallic perovskite solar cell and supercapacitor.

PubMed

Xu, Xiaobao; Li, Shaohui; Zhang, Hua; Shen, Yan; Zakeeruddin, Shaik M; Graetzel, Michael; Cheng, Yi-Bing; Wang, Mingkui

2015-02-24

We present an investigation on a power pack combining a CH3NH3PbI3-based solar cell with a polypyrrole-based supercapacitor and evaluate its performance as an energy pack. The package achieved an energy storage efficiency of 10%, which is much higher than that of other systems combining a PV cell with a supercapacitor. We find a high output voltage of 1.45 V for the device under AM 1.5G illumination when the CH3NH3PbI3-based solar cell is connected in series with a polypyrrole-based supercapacitor. This system affords continuous output of electric power by using CH3NH3PbI3-based solar cell as an energy source mitigating transients caused by light intensity fluctuations or the diurnal cycle.

Process development for single-crystal silicon solar cells

NASA Astrophysics Data System (ADS)

Bohra, Mihir H.

Solar energy is a viable, rapidly growing and an important renewable alternative to other sources of energy generation because of its abundant supply and low manufacturing cost. Silicon still remains the major contributor for manufacturing solar cells accounting for 80% of the market share. Of this, single-crystal solar cells account for half of the share. Laboratory cells have demonstrated 25% efficiency; however, commercial cells have efficiencies of 16% - 20% resulting from a focus on implementation processes geared to rapid throughput and low cost, thereby reducing the energy pay-back time. An example would be the use of metal pastes which dissolve the dielectric during the firing process as opposed to lithographically defined contacts. With current trends of single-crystal silicon photovoltaic (PV) module prices down to 0.60/W, almost all other PV technologies are challenged to remain cost competitive. This presents a unique opportunity in revisiting the PV cell fabrication process and incorporating moderately more expensive IC process practices into PV manufacturing. While they may drive the cost toward a 1/W benchmark, there is substantial room to "experiment", leading to higher efficiencies which will help maintain the overall system cost. This work entails a turn-key process designed to provide a platform for rapid evaluation of novel materials and processes. A two-step lithographic process yielding a baseline 11% - 13% efficient cell is described. Results of three studies have shown improvements in solar cell output parameters due to the inclusion of a back-surface field implant, a higher emitter doping and also an additional RCA Clean.

A photovoltaic catenary-tent array for the Martian surface

NASA Technical Reports Server (NTRS)

Crutchik, M.; Colozza, Anthony J.; Appelbaum, J.

1993-01-01

To provide electrical power during an exploration mission to Mars, a deployable tent-shaped structure with a flexible photovoltaic (PV) blanket is proposed. The array is designed with a self-deploying mechanism utilizing pressurized gas expansion. The structural design for the array uses a combination of cables, beams, and columns to support and deploy the PV blanket. Under the force of gravity a cable carrying a uniform load will take the shape of a catenary curve. A catenary-tent collector is self shadowing which must be taken into account in the solar radiation calculation. The shape and the area of the shadow on the array was calculated and used in the determination of the global radiation on the array. The PV blanket shape and structure dimension were optimized to achieve a configuration which maximizes the specific power (W/kg). The optimization was performed for four types of PV blankets (Si, GaAs/Ge, GaAs CLEFT, and amorphous Si) and four types of structure materials (Carbon composite, Aramid Fiber composite, Aluminum, and Magnesium). The results show that the catenary shape of the PV blanket, which produces the highest specific power, corresponds to zero end angle at the base with respect to the horizontal. The tent angle is determined by the combined effect of the array structure specific mass and the PV blanket output power. The combination of carbon composite structural material and GaAs CLEFT solar cells produce the highest specific power. The study was carried out for two sites on Mars corresponding to the Viking Lander locations. The designs were also compared for summer, winter, and yearly operation.

Amelioration of improper differentiation of somatostatin-positive interneurons by triiodothyronine in a growth-retarded hypothyroid mouse strain.

PubMed

Uchida, Katsuya; Taguchi, Yusuke; Sato, Chika; Miyazaki, Hidetaka; Kobayashi, Kenichi; Kobayashi, Tetsuya; Itoi, Keiichi

2014-01-24

Thyroid hormone (TH) plays an important role in brain development, and TH deficiency during pregnancy or early postnatal periods leads to neurological disorders such as cretinism. Hypothyroidism reduces the number of parvalbumin (PV)-positive interneurons in the neocortex and hippocampus. Here we used a mouse strain (growth-retarded; grt) that shows growth retardation and hypothyroidism to examine whether somatostatin (Sst)-positive interneurons that are generated from the same pool of neural progenitor cells as PV-positive cells are also altered by TH deficiency. The number of PV-positive interneurons was significantly decreased in the neocortex and hippocampus of grt mice as compared with normal control mice. In contrast to the decrease in the number of PV neurons, the number of Sst-positive interneurons in grt mice was increased in the stratum oriens of the hippocampus and the hilus of the dentate gyrus, although their number was unchanged in the neocortex. These changes were reversed by triiodothyronine administration from postnatal day (PD) 0 to 20. TH supplementation that was initiated after PD21 did not, however, affect the number of PV- or Sst-positive cells. These results suggest that during the first three postnatal weeks, TH may be critical for the generation of subpopulations of interneurons. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Performance testing and module monitoring at the EC Necessary steps to develop cost-effective PV modules

NASA Astrophysics Data System (ADS)

Krebs, K.

Testing programs carried out by the European Communities to establish testing techniques and standards for verifying the reliability and integrity of solar cells intended for the marketplace are described. The efforts are being expended to assure quality control and certification for photovoltaic (PV) products manufactured in any of the member nations. The failure rate for PV modules was lowered to 0.5 pct/year by 1981, and single cell failures are projected to be lowered to 0.00001/yr, connectors to 0.001/yr, and batteries to 0.01/yr. Day/night thermal cycling causes the most dominant type of failures, i.e., cracked cells and interconnect defects. Tests have been standardized for inspection, verification, performance, mechanical loading, hail impact, damp heat, high temperature long exposure, hot-spot heating, thermal cycling, and humidity-freezing tolerance.

Automated solar cell assembly team process research

NASA Astrophysics Data System (ADS)

Nowlan, M. J.; Hogan, S. J.; Darkazalli, G.; Breen, W. F.; Murach, J. M.; Sutherland, S. F.; Patterson, J. S.

1994-06-01

This report describes work done under the Photovoltaic Manufacturing Technology (PVMaT) project, Phase 3A, which addresses problems that are generic to the photovoltaic (PV) industry. Spire's objective during Phase 3A was to use its light soldering technology and experience to design and fabricate solar cell tabbing and interconnecting equipment to develop new, high-yield, high-throughput, fully automated processes for tabbing and interconnecting thin cells. Areas that were addressed include processing rates, process control, yield, throughput, material utilization efficiency, and increased use of automation. Spire teamed with Solec International, a PV module manufacturer, and the University of Massachusetts at Lowell's Center for Productivity Enhancement (CPE), automation specialists, who are lower-tier subcontractors. A number of other PV manufacturers, including Siemens Solar, Mobil Solar, Solar Web, and Texas instruments, agreed to evaluate the processes developed under this program.

The presence of betapapillomavirus antibodies around transplantation predicts the development of keratinocyte carcinoma in organ transplant recipients: a cohort study.

PubMed

Genders, Roel E; Mazlom, Hadi; Michel, Angelika; Plasmeijer, Elsemieke I; Quint, Koen D; Pawlita, Michael; van der Meijden, Els; Waterboer, Tim; de Fijter, Hans; Claas, Frans H; Wolterbeek, Ron; Feltkamp, Mariet C W; Bouwes Bavinck, Jan Nico

2015-05-01

Organ transplant recipients (OTRs) have an increased risk of developing keratinocyte carcinomas (KCs). The aim of this study was to correlate infection with human papillomaviruses (HPVs) belonging to the beta genus (Beta-papillomavirus (Beta-PV)) at transplantation with later development of KCs. In a cohort study, sera collected between 1 year before and 1 year after transplantation of OTRs transplanted between 1990 and 2006 were tested for antibody responses against the L1 capsid antigen of Beta-PV and other HPV genera (Gamma-, Mu-, Nu-, and Alpha-PV) using multiplex serology. The OTRs were followed for a maximum of 22 years. Cox regression models with KC, squamous cell carcinoma (SCC), and basal cell carcinoma (BCC) as outcome variables were used. Out of 445 OTRs, 60 had developed KC: 14 developed only SCC, 24 only BCC, and 22 both types of KC. The time-dependent hazard ratio (HR) to develop either or both types of KC, adjusted for age, sex, and transplanted organ, in tested Beta-PV-seropositive OTR around the time of transplantation compared with Beta-PV-seronegative OTR was 2.9 (95% confidence interval (CI) 1.3-6.4). The HR for SCC was 2.9 (95% CI 0.99-8.5) and for BCC it was 3.1 (95% CI 1.2-8.0). There was also an association between Mu-PV seropositivity and KC, but there were no significant associations between other HPV genera tested and KC. A positive seroresponse for Beta-PV around transplantation significantly predicted the development of KC in OTRs up to 22 years later, providing additional evidence that infection with Beta-PV has a role in KC carcinogenesis.

Fault detection and diagnosis of photovoltaic systems

NASA Astrophysics Data System (ADS)

Wu, Xing

The rapid growth of the solar industry over the past several years has expanded the significance of photovoltaic (PV) systems. One of the primary aims of research in building-integrated PV systems is to improve the performance of the system's efficiency, availability, and reliability. Although much work has been done on technological design to increase a photovoltaic module's efficiency, there is little research so far on fault diagnosis for PV systems. Faults in a PV system, if not detected, may not only reduce power generation, but also threaten the availability and reliability, effectively the "security" of the whole system. In this paper, first a circuit-based simulation baseline model of a PV system with maximum power point tracking (MPPT) is developed using MATLAB software. MATLAB is one of the most popular tools for integrating computation, visualization and programming in an easy-to-use modeling environment. Second, data collection of a PV system at variable surface temperatures and insolation levels under normal operation is acquired. The developed simulation model of PV system is then calibrated and improved by comparing modeled I-V and P-V characteristics with measured I--V and P--V characteristics to make sure the simulated curves are close to those measured values from the experiments. Finally, based on the circuit-based simulation model, a PV model of various types of faults will be developed by changing conditions or inputs in the MATLAB model, and the I--V and P--V characteristic curves, and the time-dependent voltage and current characteristics of the fault modalities will be characterized for each type of fault. These will be developed as benchmark I-V or P-V, or prototype transient curves. If a fault occurs in a PV system, polling and comparing actual measured I--V and P--V characteristic curves with both normal operational curves and these baseline fault curves will aid in fault diagnosis.

Nanogap near-field thermophotovoltaics.

PubMed

Fiorino, Anthony; Zhu, Linxiao; Thompson, Dakotah; Mittapally, Rohith; Reddy, Pramod; Meyhofer, Edgar

2018-06-18

Conversion of heat to electricity via solid-state devices is of great interest and has led to intense research of thermoelectric materials 1,2 . Alternative approaches for solid-state heat-to-electricity conversion include thermophotovoltaic (TPV) systems where photons from a hot emitter traverse a vacuum gap and are absorbed by a photovoltaic (PV) cell to generate electrical power. In principle, such systems may also achieve higher efficiencies and offer more versatility in use. However, the typical temperature of the hot emitter remains too low (<1,000 K) to achieve a sufficient photon flux to the PV cell, limiting practical applications. Theoretical proposals 3-12 suggest that near-field (NF) effects 13-18 that arise in nanoscale gaps may be leveraged to increase the photon flux to the PV cell and significantly enhance the power output. Here, we describe functional NFTPV devices consisting of a microfabricated system and a custom-built nanopositioner and demonstrate an ~40-fold enhancement in the power output at nominally 60 nm gaps relative to the far field. We systematically characterize this enhancement over a range of gap sizes and emitter temperatures, and for PV cells with two different bandgap energies. We anticipate that this technology, once optimized, will be viable for waste heat recovery applications.

Solar receiver with integrated optics

NASA Astrophysics Data System (ADS)

Jiang, Lun; Winston, Roland

2012-10-01

The current challenge for PV/Thermal (PV/T) systems is the reduction of radiation heat loss. Compared to solar thermal selective coating, the solar cells cannot be used as an efficient thermal absorber due to their large emissivity of the encapsulation material. Many commercial PV/T products therefore require a high concentration (more than 10x) to reach an acceptable thermal efficiency for their receivers. Such a concentration system inevitably has to track or semi-track, which induces additional cost and collects only the direct radiation from the sun. We propose a new PV/T design using a vacuum encapsulated thin film cell to solve this problem. The proposed design also collects the diffuse sun light efficiently by using an external compound parabolic concentrator (XCPC). Since the transparent electrode (TCO) of thin film cell is inherently transparent in visible light and reflective beyond infrared, this design uses this layer instead of the conventional solar cell encapsulation as the outmost heat loss surface. By integrating such a vacuum design with a tube shaped absorber, we reduce the complexity of conducting the heat energy and electricity out of the device. A low concentration standalone non-tracking solar collector is proposed in this paper. We also analyzed the thermosyphon system configuration using heat transfer and ray tracing models. The economics of such a receiver are presented.

The development and performance of smud grid-connected photovoltaic projects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osborn, D.E.; Collier, D.E.

1995-11-01

The utility grid-connected market has been identified as a key market to be developed to accelerate the commercialization of photovoltaics. The Sacramento Municipal Utility District (SMUD) has completed the first two years of a continuing commercialization effort based on two years of a continuing commercialization effort based on the sustained, orderly development of the grid-connected, utility PV market. This program is aimed at developing the experience needed to successfully integrate PV as distributed generation into the utility system and to stimulate the collaborative processes needed to accelerate the cost reductions necessary for PV to be cost-effective in these applications bymore » the year 2000. In the first two years, SMUD has installed over 240 residential and commercial building, grid-connected, rooftop, {open_quotes}PV Pioneer{close_quotes} systems totaling over 1MW of capacity and four substation sited, grid-support PV systems totaling 600 kW bringing the SMUD distributed PV power systems to over 3.7 MW. The 1995 SMUD PV Program will add another approximately 800 kW of PV systems to the District`s distributed PV power system. SMUD also established a partnership with its customers through the PV Pioneer {open_quotes}green pricing{close_quotes} program to advance PV commercialization.« less

Modeling and control of hybrid wind/photovoltaic/fuel cell distributed generation systems

NASA Astrophysics Data System (ADS)

Wang, Caisheng

Due to ever increasing energy consumption, rising public awareness of environmental protection, and steady progress in power deregulation, alternative (i.e., renewable and fuel cell based) distributed generation (DG) systems have attracted increased interest. Wind and photovoltaic (PV) power generation are two of the most promising renewable energy technologies. Fuel cell (FC) systems also show great potential in DG applications of the future due to their fast technology development and many merits they have, such as high efficiency, zero or low emission (of pollutant gases) and flexible modular structure. The modeling and control of a hybrid wind/PV/FC DG system is addressed in this dissertation. Different energy sources in the system are integrated through an AC bus. Dynamic models for the main system components, namely, wind energy conversion system (WECS), PV energy conversion system (PVECS), fuel cell, electrolyzer, power electronic interfacing circuits, battery, hydrogen storage tank, gas compressor and gas pressure regulator, are developed. Two types of fuel cells have been modeled in this dissertation: proton exchange membrane fuel cell (PEMFC) and solid oxide fuel cell (SOFC). Power control of a grid-connected FC system as well as load mitigation control of a stand-alone FC system are investigated. The pitch angle control for WECS, the maximum power point tracking (MPPT) control for PVECS, and the control for electrolyzer and power electronic devices, are also addressed in the dissertation. Based on the dynamic component models, a simulation model for the proposed hybrid energy system has been developed using MATLAB/Simulink. The overall power management strategy for coordinating the power flows among the different energy sources is presented in the dissertation. Simulation studies have been carried out to verify the system performance under different scenarios using a practical load profile and real weather data. The results show that the overall power management strategy is effective and the power flows among the different energy sources and the load demand is balanced successfully. The DG's impacts on the existing power system are also investigated in this dissertation. Analytical methods for finding optimal sites to deploy DG sources in power systems are presented and verified with simulation studies.

Photovoltaic Manufacturing Consortium (PVMC) – Enabling America’s Solar Revolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metacarpa, David

The U.S. Photovoltaic Manufacturing Consortium (US-PVMC) is an industry-led consortium which was created with the mission to accelerate the research, development, manufacturing, field testing, commercialization, and deployment of next-generation solar photovoltaic technologies. Formed as part of the U.S. Department of Energy's (DOE) SunShot initiative, and headquartered in New York State, PVMC is managed by the State University of New York Polytechnic Institute (SUNY Poly) at the Colleges of Nanoscale Science and Engineering. PVMC is a hybrid of industry-led consortium and manufacturing development facility, with capabilities for collaborative and proprietary industry engagement. Through its technology development programs, advanced manufacturing development facilities,more » system demonstrations, and reliability and testing capabilities, PVMC has demonstrated itself to be a recognized proving ground for innovative solar technologies and system designs. PVMC comprises multiple locations, with the core manufacturing and deployment support activities conducted at the Solar Energy Development Center (SEDC), and the core Si wafering and metrology technologies being headed out of the University of Central Florida. The SEDC provides a pilot line for proof-of-concept prototyping, offering critical opportunities to demonstrate emerging concepts in PV manufacturing, such as evaluations of innovative materials, system components, and PV system designs. The facility, located in Halfmoon NY, encompasses 40,000 square feet of dedicated PV development space. The infrastructure and capabilities housed at PVMC includes PV system level testing at the Prototype Demonstration Facility (PDF), manufacturing scale cell & module fabrication at the Manufacturing Development Facility (MDF), cell and module testing, reliability equipment on its PV pilot line, all integrated with a PV performance database and analytical characterizations for PVMC and its partners test and commercial arrays. Additional development and deployment support are also housed at the SEDC, such as cost modeling and cost model based development activities for PV and thin film modules, components, and system level designs for reduced LCOE through lower installation hardware costs, labor reductions, soft costs and reduced operations and maintenance costs. The progression of the consortium activities started with infrastructure and capabilities build out focused on CIGS thin film photovoltaics, with a particular focus on flexible cell and module production. As marketplace changes and partners objectives shifted, the consortium shifted heavily towards deployment and market pull activities including Balance of System, cost modeling, and installation cost reduction efforts along with impacts to performance and DER operational costs. The consortium consisted of a wide array of PV supply chain companies from equipment and component suppliers through national developers and installers with a particular focus on commercial scale deployments (typically 25 to 2MW installations). With DOE funding ending after the fifth budget period, the advantages and disadvantages of such a consortium is detailed along with potential avenues for self-sustainability is reviewed.« less

Development of a reverse transcription-loop-mediated isothermal amplification (RT-LAMP) system for a highly sensitive detection of enterovirus in the stool samples of acute flaccid paralysis cases.

PubMed

Arita, Minetaro; Ling, Hua; Yan, Dongmei; Nishimura, Yorihiro; Yoshida, Hiromu; Wakita, Takaji; Shimizu, Hiroyuki

2009-12-16

In the global eradication program for poliomyelitis, the laboratory diagnosis plays a critical role by isolating poliovirus (PV) from the stool samples of acute flaccid paralysis (AFP) cases. In this study, we developed a reverse transcription-loop-mediated isothermal amplification (RT-LAMP) system for a rapid and highly sensitive detection of enterovirus including PV to identify stool samples positive for enterovirus including PV. A primer set was designed for RT-LAMP to detect enterovirus preferably those with PV-like 5'NTRs of the viral genome. The sensitivity of RT-LAMP system was evaluated with prototype strains of enterovirus. Detection of enterovirus from stool extracts was examined by using RT-LAMP system. We detected at least 400 copies of the viral genomes of PV(Sabin) strains within 90 min by RT-LAMP with the primer set. This RT-LAMP system showed a preference for Human enterovirus species C (HEV-C) strains including PV, but exhibited less sensitivity to the prototype strains of HEV-A and HEV-B (detection limits of 7,400 to 28,000 copies). Stool extracts, from which PV, HEV-C, or HEV-A was isolated in the cell culture system, were mostly positive by RT-LAMP method (positive rates of 15/16 (= 94%), 13/14 (= 93%), and 4/4 (= 100%), respectively). The positive rate of this RT-LAMP system for stool extracts from which HEV-B was isolated was lower than that of HEV-C (positive rate of 11/21 (= 52%)). In the stool samples, which were negative for enterovirus isolation by the cell culture system, we found that two samples were positive for RT-LAMP (positive rates of 2/38 (= 5.3%)). In these samples, enterovirus 96 was identified by sequence analysis utilizing a seminested PCR system. RT-LAMP system developed in this study showed a high sensitivity comparable to that of the cell culture system for the detection of PV, HEV-A, and HEV-C, but less sensitivity to HEV-B. This RT-LAMP system would be useful for the direct detection of enterovirus from the stool extracts.

Optimal Solar PV Arrays Integration for Distributed Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Omitaomu, Olufemi A; Li, Xueping

2012-01-01

Solar photovoltaic (PV) systems hold great potential for distributed energy generation by installing PV panels on rooftops of residential and commercial buildings. Yet challenges arise along with the variability and non-dispatchability of the PV systems that affect the stability of the grid and the economics of the PV system. This paper investigates the integration of PV arrays for distributed generation applications by identifying a combination of buildings that will maximize solar energy output and minimize system variability. Particularly, we propose mean-variance optimization models to choose suitable rooftops for PV integration based on Markowitz mean-variance portfolio selection model. We further introducemore » quantity and cardinality constraints to result in a mixed integer quadratic programming problem. Case studies based on real data are presented. An efficient frontier is obtained for sample data that allows decision makers to choose a desired solar energy generation level with a comfortable variability tolerance level. Sensitivity analysis is conducted to show the tradeoffs between solar PV energy generation potential and variability.« less

Effects of noise-induced hearing loss on parvalbumin and perineuronal net expression in the mouse primary auditory cortex.

PubMed

Nguyen, Anna; Khaleel, Haroun M; Razak, Khaleel A

2017-07-01

Noise induced hearing loss is associated with increased excitability in the central auditory system but the cellular correlates of such changes remain to be characterized. Here we tested the hypothesis that noise-induced hearing loss causes deterioration of perineuronal nets (PNNs) in the auditory cortex of mice. PNNs are specialized extracellular matrix components that commonly enwrap cortical parvalbumin (PV) containing GABAergic interneurons. Compared to somatosensory and visual cortex, relatively less is known about PV/PNN expression patterns in the primary auditory cortex (A1). Whether changes to cortical PNNs follow acoustic trauma remains unclear. The first aim of this study was to characterize PV/PNN expression in A1 of adult mice. PNNs increase excitability of PV+ inhibitory neurons and confer protection to these neurons against oxidative stress. Decreased PV/PNN expression may therefore lead to a reduction in cortical inhibition. The second aim of this study was to examine PV/PNN expression in superficial (I-IV) and deep cortical layers (V-VI) following noise trauma. Exposing mice to loud noise caused an increase in hearing threshold that lasted at least 30 days. PV and PNN expression in A1 was analyzed at 1, 10 and 30 days following the exposure. No significant changes were observed in the density of PV+, PNN+, or PV/PNN co-localized cells following hearing loss. However, a significant layer- and cell type-specific decrease in PNN intensity was seen following hearing loss. Some changes were present even at 1 day following noise exposure. Attenuation of PNN may contribute to changes in excitability in cortex following noise trauma. The regulation of PNN may open up a temporal window for altered excitability in the adult brain that is then stabilized at a new and potentially pathological level such as in tinnitus. Copyright © 2017 Elsevier B.V. All rights reserved.

Identification and overexpression of a knotted1-like transcription factor in switchgrass ( Panicum virgatum L.) for lignocellulosic feedstock improvement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wuddineh, Wegi A.; Mazarei, Mitra; Zhang, Ji -Yi

High biomass production and wide adaptation has made switchgrass ( Panicum virgatum L.) an important candidate lignocellulosic bioenergy crop. One major limitation of this and other lignocellulosic feedstocks is the recalcitrance of complex carbohydrates to hydrolysis for conversion to biofuels. Lignin is the major contributor to recalcitrance as it limits the accessibility of cell wall carbohydrates to enzymatic breakdown into fermentable sugars. Therefore, genetic manipulation of the lignin biosynthesis pathway is one strategy to reduce recalcitrance. Here, we identified a switchgrass Knotted1 transcription factor, PvKN1, with the aim of genetically engineering switchgrass for reduced biomass recalcitrance for biofuel production. Genemore » expression of the endogenous PvKN1 gene was observed to be highest in young inflorescences and stems. Ectopic overexpression of PvKN1 in switchgrass altered growth, especially in early developmental stages. Transgenic lines had reduced expression of most lignin biosynthetic genes accompanied by a reduction in lignin content suggesting the involvement of PvKN1 in the broad regulation of the lignin biosynthesis pathway. Moreover, the reduced expression of the Gibberellin 20-oxidase (GA20ox) gene in tandem with the increased expression of Gibberellin 2-oxidase (GA2ox) genes in transgenic PvKN1 lines suggest that PvKN1 may exert regulatory effects via modulation of GA signaling. Furthermore, overexpression of PvKN1 altered the expression of cellulose and hemicellulose biosynthetic genes and increased sugar release efficiency in transgenic lines. Our findings demonstrated that switchgrass PvKN1 is a putative ortholog of maize KN1 that is linked to plant lignification and cell wall and development traits as a major regulatory gene. Therefore, targeted overexpression of PvKN1 in bioenergy feedstocks may provide one feasible strategy for reducing biomass recalcitrance and simultaneously improving plant growth characteristics.« less

Identification and overexpression of a knotted1-like transcription factor in switchgrass ( Panicum virgatum L.) for lignocellulosic feedstock improvement

DOE PAGES

Wuddineh, Wegi A.; Mazarei, Mitra; Zhang, Ji -Yi; ...

2016-04-28

High biomass production and wide adaptation has made switchgrass ( Panicum virgatum L.) an important candidate lignocellulosic bioenergy crop. One major limitation of this and other lignocellulosic feedstocks is the recalcitrance of complex carbohydrates to hydrolysis for conversion to biofuels. Lignin is the major contributor to recalcitrance as it limits the accessibility of cell wall carbohydrates to enzymatic breakdown into fermentable sugars. Therefore, genetic manipulation of the lignin biosynthesis pathway is one strategy to reduce recalcitrance. Here, we identified a switchgrass Knotted1 transcription factor, PvKN1, with the aim of genetically engineering switchgrass for reduced biomass recalcitrance for biofuel production. Genemore » expression of the endogenous PvKN1 gene was observed to be highest in young inflorescences and stems. Ectopic overexpression of PvKN1 in switchgrass altered growth, especially in early developmental stages. Transgenic lines had reduced expression of most lignin biosynthetic genes accompanied by a reduction in lignin content suggesting the involvement of PvKN1 in the broad regulation of the lignin biosynthesis pathway. Moreover, the reduced expression of the Gibberellin 20-oxidase (GA20ox) gene in tandem with the increased expression of Gibberellin 2-oxidase (GA2ox) genes in transgenic PvKN1 lines suggest that PvKN1 may exert regulatory effects via modulation of GA signaling. Furthermore, overexpression of PvKN1 altered the expression of cellulose and hemicellulose biosynthetic genes and increased sugar release efficiency in transgenic lines. Our findings demonstrated that switchgrass PvKN1 is a putative ortholog of maize KN1 that is linked to plant lignification and cell wall and development traits as a major regulatory gene. Therefore, targeted overexpression of PvKN1 in bioenergy feedstocks may provide one feasible strategy for reducing biomass recalcitrance and simultaneously improving plant growth characteristics.« less

Expression of Vascular Endothelial Growth Factor in Odontogenic Cysts: Is There Any Impression on Clinical Outcome?

PubMed

Sadri, Donia; Farhadi, Sareh; Shahabi, Zahra; Sarshar, Samaneh

2016-01-01

The recent scientific reports have shown that angiogenesis can affect biological behavior of pathologic lesions. Regarding unique clinical outcome of Odontogenic keratocyst (OKC), the present study was aimed to compare angiogenesis in Odontogenic keratocyst and Dentigerous cyst (DC). In this experimental study, tissue sections of 46 samples of OKC and DC were stained through immunohistochemical method using Vascular Endothelial Growth Factor (VEGF) antibody. VEGF expression was evaluated in epithelial cells, fibroblasts and endothelial cells. The average percentage of stained cells in any samples was categorized to 3 groups as follows: SCORE 0: 10% of cells or less are positive. SCORE 1: 10 to 50% of cells are positive. SCORE 2: more than 50% of cells are positive. Mann-U-Whitney, T-test and chi-square was used for statistical analysis. The average of VEGF expression in 24 samples of DC was 20.2% and in 22 samples of OKC was 52.6%, respectively. The average of VEGF expression in these two cysts had statistical significant differences. (PV= 0.045). There was significant statistical differences between two cysts in the terms of VEGF SCORE (PV= 0.000). OKC samples had significantly higher SCORE for the purpose of VEGF incidence than DC. Also, there were no differences between VEGF expression in epithelial cells of two cysts (PV= 0.268) there were significant statistical differences between two cysts in terms of endothelial cell staining. The endothelial cell staining was significantly higher in OKC than DC (PV= 0.037%). Regarding higher expression of Vascular Endothelial Growth factor in OKC than DC, it seems that angiogenesis may have great impression on clinical outcome of OKC.

Individual Pressure Vessel (PV) and Common Pressure Vessel (CPV) Nickel-Hydrogen Battery Performance Under LEO Cycling Conditions

NASA Technical Reports Server (NTRS)

Miller, Thomas B.; Lewis, Harlan L.

2004-01-01

LEO life cycle testing of Individual Pressure Vessel (PV) and Common Pressure Vessel (CPV) nickel-hydrogen cell packs have been sponsored by the NASA Aerospace Flight Battery Program. The cell packs have cycled under both 35% and 60% depth-of- discharge and temperature conditions of -5 C and +lO C. The packs have been on test since as early as 1992 and have generated a substantial database. This report will provide insight into performance trends as a function of the specific cell configuration and manufacturer for eight separate nickel-hydrogen battery cell packs.

Flat-plate solar array project of the US Department of Energy's National Photovoltaics Program: Ten years of progress

NASA Technical Reports Server (NTRS)

Christensen, Elmer

1985-01-01

The Flat-Plate Solar Array (FSA) Project, a Government-sponsored photovoltaics project, was initiated in January 1975 (previously named the Low-Cost Silicon Solar Array Project) to stimulate the development of PV systems for widespread use. Its goal then was to develop PV modules with 10% efficiency, a 20-year lifetime, and a selling price of $0.50 per peak watt of generating capacity (1975 dollars). It was recognized that cost reduction of PV solar-cell and module manufacturing was the key achievement needed if PV power systems were to be economically competitive for large-scale terrestrial use.

High throughput manufacturing of thin-film CdTe photovoltaic modules. Annual subcontract report, 16 November 1993--15 November 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandwisch, D W

1995-11-01

This report describes work performed by Solar Cells, Inc. (SCI), under a 3-year subcontract to advance SCI`s PV manufacturing technologies, reduce module production costs, increase module performance, and provide the groundwork for SCI to expand its commercial production capacities. SCI will meet these objectives in three phases by designing, debugging, and operating a 20-MW/year, automated, continuous PV manufacturing line that produces 60-cm {times} 120-cm thin-film CdTe PV modules. This report describes tasks completed under Phase 1 of the US Department of Energy`s PV Manufacturing Technology program.

Power plants development in Romania

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanasescu, F.T.; Olariu, N.

1994-12-31

The Romanian PV research program initiated in 1980 has as its aim the development of the Romanian own PV network from solar cells production to demonstration projects and commercial applications. Concerning the PV grid connected systems the Romanian research program is financed by the Romanian Ministry for Research and Technology. Setting out the main objectives and the related stages of this project, in the paper are presented aspects concerning the plant configuration, its component characteristics and preliminary achieved results. The aspects which are going to be developed in the following stages of the grid-connected PV plant implementation in Romania aremore » also underlined.« less

Synergistic combination of valproic acid and oncolytic parvovirus H-1PV as a potential therapy against cervical and pancreatic carcinomas.

PubMed

Li, Junwei; Bonifati, Serena; Hristov, Georgi; Marttila, Tiina; Valmary-Degano, Séverine; Stanzel, Sven; Schnölzer, Martina; Mougin, Christiane; Aprahamian, Marc; Grekova, Svitlana P; Raykov, Zahari; Rommelaere, Jean; Marchini, Antonio

2013-10-01

The rat parvovirus H-1PV has oncolytic and tumour-suppressive properties potentially exploitable in cancer therapy. This possibility is being explored and results are encouraging, but it is necessary to improve the oncotoxicity of the virus. Here we show that this can be achieved by co-treating cancer cells with H-1PV and histone deacetylase inhibitors (HDACIs) such as valproic acid (VPA). We demonstrate that these agents act synergistically to kill a range of human cervical carcinoma and pancreatic carcinoma cell lines by inducing oxidative stress, DNA damage and apoptosis. Strikingly, in rat and mouse xenograft models, H-1PV/VPA co-treatment strongly inhibits tumour growth promoting complete tumour remission in all co-treated animals. At the molecular level, we found acetylation of the parvovirus nonstructural protein NS1 at residues K85 and K257 to modulate NS1-mediated transcription and cytotoxicity, both of which are enhanced by VPA treatment. These results warrant clinical evaluation of H-1PV/VPA co-treatment against cervical and pancreatic ductal carcinomas. © 2013 The Authors. Published by John Wiley and Sons, Ltd on behalf of EMBO.

Differential Receptive Field Properties of Parvalbumin and Somatostatin Inhibitory Neurons in Mouse Auditory Cortex.

PubMed

Li, Ling-Yun; Xiong, Xiaorui R; Ibrahim, Leena A; Yuan, Wei; Tao, Huizhong W; Zhang, Li I

2015-07-01

Cortical inhibitory circuits play important roles in shaping sensory processing. In auditory cortex, however, functional properties of genetically identified inhibitory neurons are poorly characterized. By two-photon imaging-guided recordings, we specifically targeted 2 major types of cortical inhibitory neuron, parvalbumin (PV) and somatostatin (SOM) expressing neurons, in superficial layers of mouse auditory cortex. We found that PV cells exhibited broader tonal receptive fields with lower intensity thresholds and stronger tone-evoked spike responses compared with SOM neurons. The latter exhibited similar frequency selectivity as excitatory neurons. The broader/weaker frequency tuning of PV neurons was attributed to a broader range of synaptic inputs and stronger subthreshold responses elicited, which resulted in a higher efficiency in the conversion of input to output. In addition, onsets of both the input and spike responses of SOM neurons were significantly delayed compared with PV and excitatory cells. Our results suggest that PV and SOM neurons engage in auditory cortical circuits in different manners: while PV neurons may provide broadly tuned feedforward inhibition for a rapid control of ascending inputs to excitatory neurons, the delayed and more selective inhibition from SOM neurons may provide a specific modulation of feedback inputs on their distal dendrites. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Simulation of an active cooling system for photovoltaic modules

NASA Astrophysics Data System (ADS)

Abdelhakim, Lotfi

2016-06-01

Photovoltaic cells are devices that convert solar radiation directly into electricity. However, solar radiation increases the photovoltaic cells temperature [1] [2]. The temperature has an influence on the degradation of the cell efficiency and the lifetime of a PV cell. This work reports on a water cooling technique for photovoltaic panel, whereby the cooling system was placed at the front surface of the cells to dissipate excess heat away and to block unwanted radiation. By using water as a cooling medium for the photovoltaic solar cells, the overheating of closed panel is greatly reduced without prejudicing luminosity. The water also acts as a filter to remove a portion of solar spectrum in the infrared band but allows transmission of the visible spectrum most useful for the PV operation. To improve the cooling system efficiency and electrical efficiency, uniform flow rate among the cooling system is required to ensure uniform distribution of the operating temperature of the PV cells. The aims of this study are to develop a 3D thermal model to simulate the cooling and heat transfer in Photovoltaic panel and to recommend a cooling technique for the PV panel. The velocity, pressure and temperature distribution of the three-dimensional flow across the cooling block were determined using the commercial package, Fluent. The second objective of this work is to study the influence of the geometrical dimensions of the panel, water mass flow rate and water inlet temperature on the flow distribution and the solar panel temperature. The results obtained by the model are compared with experimental results from testing the prototype of the cooling device.

Sensitivity of Rooftop PV Projections in the SunShot Vision Study to Market Assumptions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drury, E.; Denholm, P.; Margolis, R.

2013-01-01

The SunShot Vision Study explored the potential growth of solar markets if solar prices decreased by about 75% from 2010 to 2020. The SolarDS model was used to simulate rooftop PV demand for this study, based on several PV market assumptions--future electricity rates, customer access to financing, and others--in addition to the SunShot PV price projections. This paper finds that modeled PV demand is highly sensitive to several non-price market assumptions, particularly PV financing parameters.

NATIONAL ASSESSMENT OF EMISSIONS REDUCTION IMPACT FROM ROOFTOP PV

EPA Science Inventory

This effort will determine the emissions impacts to the U.S. PV generated electricity when PV systems are installed on building rooftops and employed as demand-side power supplies. The national assessment will be based on data provided by existing rooftop PV systems that have be...

Transcriptomic analysis reveals vacuolar Na+ (K+)/H+ antiporter gene contributing to growth, development, and defense in switchgrass (Panicum virgatum L.).

PubMed

Huang, Yanhua; Cui, Xin; Cen, Huifang; Wang, Kehua; Zhang, Yunwei

2018-04-10

Intracellular Na + (K + )/H + antiporters (NHXs) have pivotal functions in regulating plant growth, development, and resistance to a range of stresses. To gain insight into the molecular events underlying their actions in switchgrass (Panicum virgatum L.), we analyzed transcriptomic changes between PvNHX1-overexpression transgenic lines and wild-type (WT) plants using RNA sequencing (RNA-seq) technology. The comparison of transcriptomic data from the WT and transgenic plants revealed a large number of differentially expressed genes (DEGs) in the latter. Gene ontology (GO) and KEGG pathway analyses showed that these DEGs were associated with a wide range of functions, and participated in many biological processes. For example, we found that PvNHX1 had an important role in plant growth through its regulation of photosynthetic activity and cell expansion. In addition, PvNHX1 regulated K + homeostasis, cell expansion and pollen development, indicating that it has unique and specific roles in flower development. We also found that transgenic switchgrass exhibited a higher level of transcription of defense-related genes, especially those involved in disease resistance. We showed that PvNHX1 had an important role in plant growth and development through its regulation of photosynthetic activity, cell expansion, K + homeostasis, and pollen development. Additionally, PvNHX1 overexpression activated a complex signal transduction network in response to various biotic and abiotic stresses. In relation to plant growth, development, and defense responses, PvNHX1 also had a vital regulatory role in the formation of a series of plant hormones and transcription factors (TFs). The reliability of the RNA-seq data was confirmed by quantitative real-time PCR. Our data provide a valuable foundation for further research into the molecular mechanisms and physiological roles of NHXs in plants.

Space Station Freedom solar array panels plasma interaction test facility

NASA Technical Reports Server (NTRS)

Martin, Donald F.; Mellott, Kenneth D.

1989-01-01

The Space Station Freedom Power System will make extensive use of photovoltaic (PV) power generation. The phase 1 power system consists of two PV power modules each capable of delivering 37.5 KW of conditioned power to the user. Each PV module consists of two solar arrays. Each solar array is made up of two solar blankets. Each solar blanket contains 82 PV panels. The PV power modules provide a 160 V nominal operating voltage. Previous research has shown that there are electrical interactions between a plasma environment and a photovoltaic power source. The interactions take two forms: parasitic current loss (occurs when the currect produced by the PV panel leaves at a high potential point and travels through the plasma to a lower potential point, effectively shorting that portion of the PV panel); and arcing (occurs when the PV panel electrically discharges into the plasma). The PV solar array panel plasma interaction test was conceived to evaluate the effects of these interactions on the Space Station Freedom type PV panels as well as to conduct further research. The test article consists of two active solar array panels in series. Each panel consists of two hundred 8 cm x 8 cm silicon solar cells. The test requirements dictated specifications in the following areas: plasma environment/plasma sheath; outgassing; thermal requirements; solar simulation; and data collection requirements.

A High Pressure Post-Perovskite Phase Transition in NaMgF3--a MgSiO3 Analog Material

NASA Astrophysics Data System (ADS)

Martin, C.; Liu, H.; Crichton, W.; Parise, J. B.

2005-12-01

Since Murakami et al. (2004) identified a perovskite (pv, Pbnm) to post-perovskite (ppv, Cmcm) structural phase transition in MgSiO3, the transition has been reported to occur in many oxides at ultra-high pressures (>60 GPa). The layered ppv structure is rapidly shaping a better understanding of seismic anisotropy in the controversial D" region of the lower mantle. While the ppv unit cell may be derived from indexing of the powder pattern, the structure adopted at high pressure is experimentally ill-constrained due to compromised powder diffraction statistics typically obtained from small sample volumes at extreme conditions in the diamond anvil cell. NaMgF3, a structural analog material to MgSiO3 pv, exhibits a large compressibility and presents the possibility of reducing the pv-ppv transition pressure, allowing for improved powder statistics from a larger sample volume. In accordance with our previous theoretical and experimental evidence (Liu et al., 2005; Parise et al., 2004), we have observed a phase transition in NaMgF3 during two recent independent high pressure trials utilizing monochromatic x-ray diffraction and in-situ laser heating in the diamond anvil cell at pressures as low as 30 GPa. From our analysis thus far, we have found the unit cell of the high pressure phase cannot be indexed according to pv (Pbnm) or close permutations of ppv (Cmcm) unit cells predicted for NaMgF3 or unit cells observed for ppv MgSiO3 and MgGeO3. In addition, we have precluded a breakdown to high pressure phases of NaF and MgF3 as an explanation for the observed data. Upon pressure release, we observe diffraction peaks from the high pressure phase in the absence of pv NaMgF3, suggesting the high pressure structure is quenchable to ambient conditions. The results of the work in progress will be presented at the meeting.

Photovoltaic Grid-Connected Modeling and Characterization Based on Experimental Results.

PubMed

Humada, Ali M; Hojabri, Mojgan; Sulaiman, Mohd Herwan Bin; Hamada, Hussein M; Ahmed, Mushtaq N

2016-01-01

A grid-connected photovoltaic (PV) system operates under fluctuated weather condition has been modeled and characterized based on specific test bed. A mathematical model of a small-scale PV system has been developed mainly for residential usage, and the potential results have been simulated. The proposed PV model based on three PV parameters, which are the photocurrent, IL, the reverse diode saturation current, Io, the ideality factor of diode, n. Accuracy of the proposed model and its parameters evaluated based on different benchmarks. The results showed that the proposed model fitting the experimental results with high accuracy compare to the other models, as well as the I-V characteristic curve. The results of this study can be considered valuable in terms of the installation of a grid-connected PV system in fluctuated climatic conditions.

Photovoltaic Grid-Connected Modeling and Characterization Based on Experimental Results

PubMed Central

Humada, Ali M.; Hojabri, Mojgan; Sulaiman, Mohd Herwan Bin; Hamada, Hussein M.; Ahmed, Mushtaq N.

2016-01-01

A grid-connected photovoltaic (PV) system operates under fluctuated weather condition has been modeled and characterized based on specific test bed. A mathematical model of a small-scale PV system has been developed mainly for residential usage, and the potential results have been simulated. The proposed PV model based on three PV parameters, which are the photocurrent, IL, the reverse diode saturation current, Io, the ideality factor of diode, n. Accuracy of the proposed model and its parameters evaluated based on different benchmarks. The results showed that the proposed model fitting the experimental results with high accuracy compare to the other models, as well as the I-V characteristic curve. The results of this study can be considered valuable in terms of the installation of a grid-connected PV system in fluctuated climatic conditions. PMID:27035575

MLF1IP promotes normal erythroid proliferation and is involved in the pathogenesis of polycythemia vera.

PubMed

Feng, Gege; Zhang, Tianjiao; Liu, Jinqin; Ma, Xiaotang; Li, Bing; Yang, Lin; Zhang, Yue; Xu, Zefeng; Qin, Tiejun; Zhou, Jiaxi; Huang, Gang; Shi, Lihong; Xiao, Zhijian

2017-03-01

Myelodysplasia/myeloid leukemia factor 1-interacting protein (MLF1IP) appears to be an erythroid lineage-specific gene in mice; however, its role in normal erythropoiesis and erythropoietic disorders have not yet been elucidated. Here, we found that MLF1IP is abundantly expressed in human erythroid progenitor cells and that MLF1IP-deficiency reduces cell proliferation resulting from cell cycle arrest. Moreover, MLF1IP expression is exclusively elevated in CFU-E cells from polycythemia vera (PV) patients, and MLF1IP transgenic mice develop a PV-like disorder. Further analyses revealed that the erythroid progenitors and early-stage erythroblasts from these transgenic mice expand by up-regulating cyclin D2 and down-regulating p27 and p21. Thus, our data demonstrate that MLF1IP promotes erythroid proliferation and is involved in the pathogenesis of PV, suggesting that it might be a novel molecular target for erythropoietic disorders. © 2017 Federation of European Biochemical Societies.

[Fatty acids composition of cellular lipids of the collected and newly isolated Pseudomonas lupini strains].

PubMed

Hvozdiak, R I; Dankevych, L A; Votselko, S K; Holubets', O V

2005-01-01

Fatty acid composition of cellular lipids of 23 Pseudomonas lupini strains (Beltjukova et Koroljova 1968) has been investigated. Cellular fatty acids which contained from C10 to C19 carbon atoms have been identified. Basic fatty acid of those Pseudomonas cells are hexadecanoic, hexadecenoic and octadecanoic acids. The 3-hydroxydecanoic (C10:0 3OH), 3-hydroxydodecanoic (C12:0 3OH), 2-hydroxydodecanoic (C12:0 2OH) and cyclopropane fatty acids which contain 17 and 19 carbon atoms have been detected in cellular lipids. The cellular fatty acids spectra of 22 P. lupini strains are similar to cellular fatty acids spectrum of the type strain Pseudomonas syringae pv. syringae 8511. Pathogenic isolate 2, which fatty acid content of cell lipids significantly differ from lipids of cell fatty acids from P. lupini strains and cell lipids of fatty acids of typical strains Pseudomonas syringae pv. syringae 8511 and Pseudomonas savastanoi pv. phaseolicola 9066 is the exception.

Flexible packaging for PV modules

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.

2008-08-01

Economic, flexible packages that provide needed level of protection to organic and some other PV cells over >25-years have not yet been developed. However, flexible packaging is essential in niche large-scale applications. Typical configuration used in flexible photovoltaic (PV) module packaging is transparent frontsheet/encapsulant/PV cells/flexible substrate. Besides flexibility of various components, the solder bonds should also be flexible and resistant to fatigue due to cyclic loading. Flexible front sheets should provide optical transparency, mechanical protection, scratch resistance, dielectric isolation, water resistance, UV stability and adhesion to encapsulant. Examples are Tefzel, Tedlar and Silicone. Dirt can get embedded in soft layers such as silicone and obscure light. Water vapor transmittance rate (WVTR) of polymer films used in the food packaging industry as moisture barriers are ~0.05 g/(m2.day) under ambient conditions. In comparison, light emitting diodes employ packaging components that have WVTR of ~10-6 g/(m2.day). WVTR of polymer sheets can be improved by coating them with dense inorganic/organic multilayers. Ethylene vinyl acetate, an amorphous copolymer used predominantly by the PV industry has very high O2 and H2O diffusivity. Quaternary carbon chains (such as acetate) in a polymer lead to cleavage and loss of adhesional strength at relatively low exposures. Reactivity of PV module components increases in presence of O2 and H2O. Adhesional strength degrades due to the breakdown of structure of polymer by reactive, free radicals formed by high-energy radiation. Free radical formation in polymers is reduced when the aromatic rings are attached at regular intervals. This paper will review flexible packaging for PV modules.

DISTRIBUTED GRID-CONNECTED PHOTOVOLTAIC POWER SYSTEM EMISSION OFFSET ASSESSMENT: STATISTICAL TEST OF SIMULATED- AND MEASURED-BASED DATA

EPA Science Inventory

This study assessed the pollutant emission offset potential of distributed grid-connected photovoltaic (PV) power systems. Computer-simulated performance results were utilized for 211 PV systems located across the U.S. The PV systems' monthly electrical energy outputs were based ...

Analysis of the aging/stability process of organic solar cells based on PTB7:[70]PCBM and an alternative free-vacuum deposited cathode: the effect of active layer scaling

NASA Astrophysics Data System (ADS)

Barreiro-Argüelles, Denisse; Ramos-Ortiz, Gabriel; Maldonado, José-Luis L.; Romero-Borja, Daniel; Meneses-Nava, Marco-Antonio; Pérez-Gutiérrez, Enrique

2017-08-01

The PV performance and aging/stability of organic photovoltaic (OPV) devices based on the well-known system PTB7:[70]PCBM and an alternative air-stable electrode deposited at room conditions are fully studied when the active area is scaled by a factor of 25. On the other hand, the aging/stability processes were also studied through single diode model, impedance spectroscopy and light-beam induced current (LBIC) measurements in accordance with the established ISOS-D1 (dark storage) and ISOS-L1 (illumination conditions) protocols. Results are a good indication that the alternative cathode Field's metal (FM) cathode works as an encapsulating material and provides excellent PV performance comparable with the common and costly high-vacuum evaporated Al cathode.

Enhanced photovoltaic performance of ultrathin Si solar cells via semiconductor nanocrystal sensitization: Energy transfer vs. optical coupling effects

DOE PAGES

Hoang, Son; Ashraf, Ahsan; Eisaman, Matthew D.; ...

2015-12-07

Excitonic energy transfer (ET) offers exciting opportunities for advances in optoelectronic devices such as solar cells. While recent experimental attempts have demonstrated its potential in both organic and inorganic photovoltaics (PVs), what remains to be addressed is quantitative understanding of how different ET modes contribute to PV performance and how ET contribution is differentiated from the classical optical coupling (OC) effects. In this study, we implement an ET scheme using a PV device platform, comprising CdSe/ZnS nanocrystal energy donor and 500 nm-thick ultrathin Si acceptor layers, and present the quantitative mechanistic description of how different ET modes, distinguished from themore » OC effects, increase the light absorption and PV efficiency. We find that nanocrystal sensitization enhances the short circuit current of ultrathin Si solar cells by up to 35%, of which the efficient ET, primarily driven by a long-range radiative mode, contributes to 38% of the total current enhancement. Lastly, these results not only confirm the positive impact of ET but also provide a guideline for rationally combining the ET and OC effects for improved light harvesting in PV and other optoelectronic devices.« less

Optimal Configuration of PV System with Different Solar Cell Arrays

NASA Astrophysics Data System (ADS)

Machida, Sadayuki; Tani, Tatsuo

Photovoltaic (PV) power generation is spreading steadily, and the dispersed PV array system is increasing from the architectural restrictions. In the case of dispersed array system, if the arrays are installed in a different azimuth or if the module that constitutes array is different, mismatching loss will be generated when a single inverter is used to convert the output of arrays, because of the difference of optimal operating voltage. The loss is related to the array configuration. However the relation between array configuration and power generation output is not clear. In order to avoid generation of mismatching loss, introducing a distributed inverter system such as string inverter system or AC modules system is considered. However it is not clear which is more advantageous between a distributed system and a concentrated system. In this paper, we verified the output characteristics of two different solar cell arrays with various strings, azimuths and tilt angles, and clarified the relation between array configuration and power generation output by the computer simulations. We also compared the distributed inverter system with the concentrated inverter system, and clarified the optimal configuration of PV system with different solar cell arrays.

Enhanced photovoltaic performance of ultrathin Si solar cells via semiconductor nanocrystal sensitization: energy transfer vs. optical coupling effects.

PubMed

Hoang, Son; Ashraf, Ahsan; Eisaman, Matthew D; Nykypanchuk, Dmytro; Nam, Chang-Yong

2016-03-21

Excitonic energy transfer (ET) offers exciting opportunities for advances in optoelectronic devices such as solar cells. While recent experimental attempts have demonstrated its potential in both organic and inorganic photovoltaics (PVs), what remains to be addressed is quantitative understanding of how different ET modes contribute to PV performance and how ET contribution is differentiated from the classical optical coupling (OC) effects. In this study, we implement an ET scheme using a PV device platform, comprising CdSe/ZnS nanocrystal energy donor and 500 nm-thick ultrathin Si acceptor layers, and present the quantitative mechanistic description of how different ET modes, distinguished from the OC effects, increase the light absorption and PV efficiency. We find that nanocrystal sensitization enhances the short circuit current of ultrathin Si solar cells by up to 35%, of which the efficient ET, primarily driven by a long-range radiative mode, contributes to 38% of the total current enhancement. These results not only confirm the positive impact of ET but also provide a guideline for rationally combining the ET and OC effects for improved light harvesting in PV and other optoelectronic devices.

Promoting STEM to Young Students by Renewable Energy Applications

ERIC Educational Resources Information Center

Pecen, Recayi; Humston, Jill L.; Yildiz, Faruk

2012-01-01

The Math-Science-Engineering Technology in Iowa on Applied Renewable Energy Areas (MSETI-AREA) projects are aimed at providing area school teachers with an applied mathematics and science curriculum package based on photovoltaic (PV) power, wind power, human power and hydrogen fuel-cell fundamentals. The MSETI-AREA project has established a…

Random Surface Texturing of Silicon Dioxide Using Gold Agglomerates

DTIC Science & Technology

2016-07-01

Approved for public release; distribution unlimited. 1 1. Introduction The US Army has been developing new types of photovoltaic ( PV ) devices— solar ...light falling onto the surface of a solar cell is a major optical loss mechanism, which limits the efficiency of the PV .1,2 One method of reducing...in an AR coating on solar cells. 15. SUBJECT TERMS anti-reflective, AR coatings, textured surface structures, silicon dioxide, SiO2 16. SECURITY

A novel approach of ensuring layout regularity correct by construction in advanced technologies

NASA Astrophysics Data System (ADS)

Ahmed, Shafquat Jahan; Vaderiya, Yagnesh; Gupta, Radhika; Parthasarathy, Chittoor; Marin, Jean-Claude; Robert, Frederic

2017-03-01

In advanced technology nodes, layout regularity has become a mandatory prerequisite to create robust designs less sensitive to variations in manufacturing process in order to improve yield and minimizing electrical variability. In this paper we describe a method for designing regular full custom layouts based on design and process co-optimization. The method includes various design rule checks that can be used on-the-fly during leaf-cell layout development. We extract a Layout Regularity Index (LRI) from the layouts based on the jogs, alignments and pitches used in the design for any given metal layer. Regularity Index of a layout is the direct indicator of manufacturing yield and is used to compare the relative health of different layout blocks in terms of process friendliness. The method has been deployed for 28nm and 40nm technology nodes for Memory IP and is being extended to other IPs (IO, standard-cell). We have quantified the gain of layout regularity with the deployed method on printability and electrical characteristics by process-variation (PV) band simulation analysis and have achieved up-to 5nm reduction in PV band.

Scalable fabrication of perovskite solar cells

DOE PAGES

Li, Zhen; Klein, Talysa R.; Kim, Dong Hoe; ...

2018-03-27

Perovskite materials use earth-abundant elements, have low formation energies for deposition and are compatible with roll-to-roll and other high-volume manufacturing techniques. These features make perovskite solar cells (PSCs) suitable for terawatt-scale energy production with low production costs and low capital expenditure. Demonstrations of performance comparable to that of other thin-film photovoltaics (PVs) and improvements in laboratory-scale cell stability have recently made scale up of this PV technology an intense area of research focus. Here, we review recent progress and challenges in scaling up PSCs and related efforts to enable the terawatt-scale manufacturing and deployment of this PV technology. We discussmore » common device and module architectures, scalable deposition methods and progress in the scalable deposition of perovskite and charge-transport layers. We also provide an overview of device and module stability, module-level characterization techniques and techno-economic analyses of perovskite PV modules.« less

Contribution of Innate Cortical Mechanisms to the Maturation of Orientation Selectivity in Parvalbumin Interneurons

PubMed Central

Figueroa Velez, Dario X.; Ellefsen, Kyle L.; Hathaway, Ethan R.; Carathedathu, Mathew C.

2017-01-01

The maturation of cortical parvalbumin-positive (PV) interneurons depends on the interaction of innate and experience-dependent factors. Dark-rearing experiments suggest that visual experience determines when broad orientation selectivity emerges in visual cortical PV interneurons. Here, using neural transplantation and in vivo calcium imaging of mouse visual cortex, we investigated whether innate mechanisms contribute to the maturation of orientation selectivity in PV interneurons. First, we confirmed earlier findings showing that broad orientation selectivity emerges in PV interneurons by 2 weeks after vision onset, ∼35 d after these cells are born. Next, we assessed the functional development of transplanted PV (tPV) interneurons. Surprisingly, 25 d after transplantation (DAT) and >2 weeks after vision onset, we found that tPV interneurons have not developed broad orientation selectivity. By 35 DAT, however, broad orientation selectivity emerges in tPV interneurons. Transplantation does not alter orientation selectivity in host interneurons, suggesting that the maturation of tPV interneurons occurs independently from their endogenous counterparts. Together, these results challenge the notion that the onset of vision solely determines when PV interneurons become broadly tuned. Our results reveal that an innate cortical mechanism contributes to the emergence of broad orientation selectivity in PV interneurons. SIGNIFICANCE STATEMENT Early visual experience and innate developmental programs interact to shape cortical circuits. Visual-deprivation experiments have suggested that the onset of visual experience determines when interneurons mature in the visual cortex. Here we used neuronal transplantation and cellular imaging of visual responses to investigate the maturation of parvalbumin-positive (PV) interneurons. Our results suggest that the emergence of broad orientation selectivity in PV interneurons is innately timed. PMID:28123018

Marked elevation of serum macrophage migration inhibitory factor levels in patients with pemphigus vulgaris.

PubMed

Namazi, Mohammad Reza; Fallahzadeh, Mohammad Kazem; Shaghelani, Hassan; Kamali-Sarvestani, Eskandar

2010-02-01

There is ample evidence for involvement of macrophage migration inhibitory factor (MIF) in autoimmune and inflammatory diseases. The aim of this study was to determine whether MIF levels were raised in the sera of patients with pemphigus vulgaris (PV). Serum MIF levels were measured using ELISA method in 22 patients with active PV and 21 age- and sex-matched healthy controls and the results were compared with each other. The mean serum MIF levels was significantly higher in PV patients than in control subjects (11.99 +/- 1.63 pg/m vs. 1.83 +/- 0.22 pg/ml; P-value = 0.0001). Elevated MIF levels in the sera of PV patients could participate in disease induction by activation of T cells as well as induction of autoantibody production by B cells. Given that MIF counter-regulates the effects of steroids, MIF antagonists may prove to be very effective, novel steroid-sparing agents for this life-threatening conundrum.

Dynamic Performance Comparison for MPPT-PV Systems using Hybrid Pspice/Matlab Simulation

NASA Astrophysics Data System (ADS)

Aouchiche, N.; Becherif, M.; HadjArab, A.; Aitcheikh, M. S.; Ramadan, H. S.; Cheknane, A.

2016-10-01

The power generated by solar photovoltaic (PV) module depends on the surrounding irradiance and temperature. This paper presents a hybrid Matlab™/Pspice™ simulation model of PV system, combined with Cadence software SLPS. The hybridization is performed in order to gain the advantages of both simulation tools such as accuracy and efficiency in both Pspice electronic circuit and Matlab™ mathematical modelling respectively. For this purpose, the PV panel and the boost converter are developed using Pspice™ and hybridized with the mathematical Matlab™ model of maximum power point method controller (MPPT) through SLPS. The main objective is verify the significance of using the proposed hybrid simulation techniques in comparing the different MPPT algorithms such as the perturbation and observation (P&O), incremental of conductance (Inc-Cond) and counter reaction voltage using pilot cell (Pilot-Cell). Various simulations are performed under different atmospheric conditions in order to evaluate the dynamic behaviour for the system under study in terms of stability, efficiency and rapidity.

Nrp2 is sufficient to instruct circuit formation of mitral-cells to mediate odour-induced attractive social responses.

PubMed

Inokuchi, Kasumi; Imamura, Fumiaki; Takeuchi, Haruki; Kim, Ryang; Okuno, Hiroyuki; Nishizumi, Hirofumi; Bito, Haruhiko; Kikusui, Takefumi; Sakano, Hitoshi

2017-07-21

Odour information induces various innate responses that are critical to the survival of the individual and for the species. An axon guidance molecule, Neuropilin 2 (Nrp2), is known to mediate targeting of olfactory sensory neurons (primary neurons), to the posteroventral main olfactory bulb (PV MOB) in mice. Here we report that Nrp2-positive (Nrp2 + ) mitral cells (MCs, second-order neurons) play crucial roles in transmitting attractive social signals from the PV MOB to the anterior part of medial amygdala (MeA). Semaphorin 3F, a repulsive ligand to Nrp2, regulates both migration of Nrp2 + MCs to the PV MOB and their axonal projection to the anterior MeA. In the MC-specific Nrp2 knockout mice, circuit formation of Nrp2 + MCs and odour-induced attractive social responses are impaired. In utero, electroporation demonstrates that activation of the Nrp2 gene in MCs is sufficient to instruct their circuit formation from the PV MOB to the anterior MeA.

[Serum levels of antibodies for IgG, IgA, and IgM against the fungi antigen in psoriasis vulgaris].

PubMed

Liang, Yun-sheng; Wen, Hai-quan; Xiao, Rong

2003-12-01

To detect the serum levels of antibodies against Malassezia further and Candida albicans in patients with psoriasis vulgaris (PV), and to investigate the relationship between Malassezia furfur or Candida albicans and pathogenesis of PV. The serum levels of antibodies for IgG, IgA, and IgM against the whole cell antigen Wag and soluble antigen (Sag) of Malassezia fufur and Candida albicans in 40 PV patients and 20 healthy controls were detected by indirect-ELISA, RESULTS: The serum levels of IgG against Wag of Malassezia furfur and Candida albicans were significantly higher in PV patients than those in the healthy controls (P < 0.01, P < 0.05, respectively), The serum levels of IgM against Sag of Malassezia furfur and Candida albican, IgA against Sag of Candida albicans were significantly lower in PV patients than those in the healthy controls (P < 0.05). There are some humoral immunity abnormalties in PV patients. Malassezia furfur and Candida albicans may be related to the pathogenesis of PV.

PVMirrors: Hybrid PV/CSP collectors that enable lower LCOEs

NASA Astrophysics Data System (ADS)

Fisher, Kate; Yu, Zhengshan Jason; Striling, Rob; Holman, Zachary

2017-06-01

The primary challenge with concentrating solar power (CSP) is that the conversion efficiency is low—and the cost high—compared to that of photovoltaics (PV), and the primary challenge with PV is that the energy generated cannot be stored cost effectively. We introduce a technology that hybridizes CSP and PV, resulting in power plants with high energy conversion efficiency and affordable storage. This is accomplished by replacing silvered troughs (or heliostat facets) with "PVMirrors" that and direct photons of each wavelength to the converter (PV or thermal) that may best use them. A PVMirror looks like a curved PV module that includes a spectrum-splitting dichroic mirror film; this film, which is the heart of the technology, transmits near-infrared light to the underlying silicon PV cells while reflecting both longer and shorter wavelengths to a thermal absorber tube. This paper investigates the optical performance of dichroic mirror film, the specularity of PVMirrors, and the anticipated levelized cost of energy (LCOE) from a PVMirror power plant. PVMirrors are found to decrease LCOE by more than 15% relative to CSP while retaining full dispatchability.

How reliable are efficiency measurements of perovskite solar cells? The first inter-comparison, between two accredited and eight non-accredited laboratories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunbar, Ricky B.; Duck, Benjamin C.; Moriarty, Tom E.

Perovskite materials have generated significant interest from academia and industry as a potential component in next-generation, high-efficiency, low-cost, photovoltaic (PV) devices. The record efficiency reported for perovskite solar cells has risen rapidly, and is now more than 22%. However, due to their complex dynamic behaviour, the process of measuring the efficiency of perovskite solar cells appears to be much more complicated than for other technologies. It has long been acknowledged that this is likely to greatly reduce the reliability of reported efficiency measurements, but the quantitative extent to which this occurs has not been determined. To investigate this, we conductmore » the first major inter-comparison of this PV technology. The participants included two labs accredited for PV performance measurement (CSIRO and NREL) and eight PV research laboratories. We find that the inter-laboratory measurement variability can be almost ten times larger for a slowly responding perovskite cell than for a control silicon cell. We show that for such a cell, the choice of measurement method, far more so than measurement hardware, is the single-greatest cause for this undesirably large variability. We provide recommendations for identifying the most appropriate method for a given cell, depending on its stabilization and degradation behaviour. Moreover, the results of this study suggest that identifying a consensus technique for accurate and meaningful efficiency measurements of perovskite solar cells will lead to an immediate improvement in reliability. This, in turn, should assist device researchers to correctly evaluate promising new materials and fabrication methods, and further boost the development of this technology.« less

How reliable are efficiency measurements of perovskite solar cells? The first inter-comparison, between two accredited and eight non-accredited laboratories

DOE PAGES

Dunbar, Ricky B.; Duck, Benjamin C.; Moriarty, Tom E.; ...

2017-10-24

Perovskite materials have generated significant interest from academia and industry as a potential component in next-generation, high-efficiency, low-cost, photovoltaic (PV) devices. The record efficiency reported for perovskite solar cells has risen rapidly, and is now more than 22%. However, due to their complex dynamic behaviour, the process of measuring the efficiency of perovskite solar cells appears to be much more complicated than for other technologies. It has long been acknowledged that this is likely to greatly reduce the reliability of reported efficiency measurements, but the quantitative extent to which this occurs has not been determined. To investigate this, we conductmore » the first major inter-comparison of this PV technology. The participants included two labs accredited for PV performance measurement (CSIRO and NREL) and eight PV research laboratories. We find that the inter-laboratory measurement variability can be almost ten times larger for a slowly responding perovskite cell than for a control silicon cell. We show that for such a cell, the choice of measurement method, far more so than measurement hardware, is the single-greatest cause for this undesirably large variability. We provide recommendations for identifying the most appropriate method for a given cell, depending on its stabilization and degradation behaviour. Moreover, the results of this study suggest that identifying a consensus technique for accurate and meaningful efficiency measurements of perovskite solar cells will lead to an immediate improvement in reliability. This, in turn, should assist device researchers to correctly evaluate promising new materials and fabrication methods, and further boost the development of this technology.« less

Efficiently-cooled plasmonic amorphous silicon solar cells integrated with a nano-coated heat-pipe plate

PubMed Central

Zhang, Yinan; Du, Yanping; Shum, Clifford; Cai, Boyuan; Le, Nam Cao Hoai; Chen, Xi; Duck, Benjamin; Fell, Christopher; Zhu, Yonggang; Gu, Min

2016-01-01

Solar photovoltaics (PV) are emerging as a major alternative energy source. The cost of PV electricity depends on the efficiency of conversion of light to electricity. Despite of steady growth in the efficiency for several decades, little has been achieved to reduce the impact of real-world operating temperatures on this efficiency. Here we demonstrate a highly efficient cooling solution to the recently emerging high performance plasmonic solar cell technology by integrating an advanced nano-coated heat-pipe plate. This thermal cooling technology, efficient for both summer and winter time, demonstrates the heat transportation capability up to ten times higher than those of the metal plate and the conventional wickless heat-pipe plates. The reduction in temperature rise of the plasmonic solar cells operating under one sun condition can be as high as 46%, leading to an approximate 56% recovery in efficiency, which dramatically increases the energy yield of the plasmonic solar cells. This newly-developed, thermally-managed plasmonic solar cell device significantly extends the application scope of PV for highly efficient solar energy conversion. PMID:27113558

Efficiently-cooled plasmonic amorphous silicon solar cells integrated with a nano-coated heat-pipe plate.

PubMed

Zhang, Yinan; Du, Yanping; Shum, Clifford; Cai, Boyuan; Le, Nam Cao Hoai; Chen, Xi; Duck, Benjamin; Fell, Christopher; Zhu, Yonggang; Gu, Min

2016-04-26

Solar photovoltaics (PV) are emerging as a major alternative energy source. The cost of PV electricity depends on the efficiency of conversion of light to electricity. Despite of steady growth in the efficiency for several decades, little has been achieved to reduce the impact of real-world operating temperatures on this efficiency. Here we demonstrate a highly efficient cooling solution to the recently emerging high performance plasmonic solar cell technology by integrating an advanced nano-coated heat-pipe plate. This thermal cooling technology, efficient for both summer and winter time, demonstrates the heat transportation capability up to ten times higher than those of the metal plate and the conventional wickless heat-pipe plates. The reduction in temperature rise of the plasmonic solar cells operating under one sun condition can be as high as 46%, leading to an approximate 56% recovery in efficiency, which dramatically increases the energy yield of the plasmonic solar cells. This newly-developed, thermally-managed plasmonic solar cell device significantly extends the application scope of PV for highly efficient solar energy conversion.

Efficiently-cooled plasmonic amorphous silicon solar cells integrated with a nano-coated heat-pipe plate

NASA Astrophysics Data System (ADS)

Zhang, Yinan; Du, Yanping; Shum, Clifford; Cai, Boyuan; Le, Nam Cao Hoai; Chen, Xi; Duck, Benjamin; Fell, Christopher; Zhu, Yonggang; Gu, Min

2016-04-01

Solar photovoltaics (PV) are emerging as a major alternative energy source. The cost of PV electricity depends on the efficiency of conversion of light to electricity. Despite of steady growth in the efficiency for several decades, little has been achieved to reduce the impact of real-world operating temperatures on this efficiency. Here we demonstrate a highly efficient cooling solution to the recently emerging high performance plasmonic solar cell technology by integrating an advanced nano-coated heat-pipe plate. This thermal cooling technology, efficient for both summer and winter time, demonstrates the heat transportation capability up to ten times higher than those of the metal plate and the conventional wickless heat-pipe plates. The reduction in temperature rise of the plasmonic solar cells operating under one sun condition can be as high as 46%, leading to an approximate 56% recovery in efficiency, which dramatically increases the energy yield of the plasmonic solar cells. This newly-developed, thermally-managed plasmonic solar cell device significantly extends the application scope of PV for highly efficient solar energy conversion.

Emissions from photovoltaic life cycles.

PubMed

Fthenakis, Vasilis M; Kim, Hyung Chul; Alsema, Erik

2008-03-15

Photovoltaic (PV) technologies have shown remarkable progress recently in terms of annual production capacity and life cycle environmental performances, which necessitate timely updates of environmental indicators. Based on PV production data of 2004-2006, this study presents the life-cycle greenhouse gas emissions, criteria pollutant emissions, and heavy metal emissions from four types of major commercial PV systems: multicrystalline silicon, monocrystalline silicon, ribbon silicon, and thin-film cadmium telluride. Life-cycle emissions were determined by employing average electricity mixtures in Europe and the United States during the materials and module production for each PV system. Among the current vintage of PV technologies, thin-film cadmium telluride (CdTe) PV emits the least amount of harmful air emissions as it requires the least amount of energy during the module production. However, the differences in the emissions between different PV technologies are very small in comparison to the emissions from conventional energy technologies that PV could displace. As a part of prospective analysis, the effect of PV breeder was investigated. Overall, all PV technologies generate far less life-cycle air emissions per GWh than conventional fossil-fuel-based electricity generation technologies. At least 89% of air emissions associated with electricity generation could be prevented if electricity from photovoltaics displaces electricity from the grid.

Whooping cough surveillance in France in pediatric private practice in 2006-2015.

PubMed

Guiso, Nicole; Levy, Corinne; Romain, Olivier; Guillot, Sophie; Werner, Andreas; Rondeau, Marie Charlotte; Béchet, Stéphane; Cohen, Robert

2017-10-27

Increasing incidence of whooping cough (pertussis) has been reported in many countries, attributed to a switch from whole-cell pertussis-containing vaccine (wPV) to acellular PV (aPV) and circulation of the pertactin non-producing Bordetella pertussis. The present study aimed to estimate the duration of immunity conferred by PVs in children in France with data from an ongoing pediatric ambulatory surveillance of pertussis. A total of 64 pediatricians throughout France enrolled children with suspected pertussis. A standardized data form was used to collect data on age sex, vaccination status, brand of wPV or aPV and source of infection. Confirmed cases were positive on culture and/or real-time Polymerase Chain Reaction (for B.-non-classified or B. pertussis or B. parapertussis) and/or pertussis serology. Between October 2006 and December 2015, 149 cases of confirmed Bordetella infections were reported, 86 infected with B. pertussis and 55 B. non-classified. Fifteen children (10.1%) were not vaccinated, and 26 (17.4%) were partially vaccinated. The mean age was greater for children who received 4 doses of wPV (11.3±2.2, p<0.001) or a combination of wPV and aPV (10.5±3.3, p<0.001) than only aPV (7.2±2.4years). The mean duration of cough before a visit to a pediatrician was longer for children with wPV or a combination of wPV and aPV than only aPV (23.8±10.1 and 25.0±25.6vs 13.6±10.0days). Despite the use of a more sensitive diagnostic method and emergence of pertactin non producing B. pertussis, in France context, aPV-induced immunity still protects against pertussis; however, the mean duration of immunity is about 6 to 7years, compared to 9years for wPV vaccine, after the primary vaccination and one booster (3+1 doses). Copyright © 2017 Elsevier Ltd. All rights reserved.

Pulmonary vein activity does not predict the outcome of catheter ablation for persistent atrial fibrillation: A long-term multicenter prospective study.

PubMed

Prabhu, Sandeep; Kalla, Manish; Peck, Kah Y; Voskoboinik, Aleksandr; McLellan, Alex J A; Pathik, Bupesh; Nalliah, Chrishan J; Wong, Geoff R; Sugumar, Hariharan; Azzopardi, Sonia M; Lee, Geoffrey; Ling, Liang-Han; Kalman, Jonathan M; Kistler, Peter M

2018-03-02

Pulmonary vein (PV) isolation (PVI) remains the cornerstone of catheter ablation (CA) in persistent atrial fibrillation (AF) (PeAF), although less successful than for paroxysmal AF. Whether rapid or fibrillatory (PV AF) PV firing may identify patients with PeAF more likely to benefit from a PV-based ablation approach is unclear. The purpose of this study was to determine the relationship between the PV cycle length (PVCL) and the PV AF outcome after CA. Before ablation, the multipolar catheter was placed in each PV and the left atrial appendage (LAA) for 100 consecutive cycles. The presence of PV AF, the average PVCL of all 4 veins (PV 4VAverage ), the fastest vein average (PV FVAverage ), the fastest cycle length (PV Fast ) both individually and relative to the average LAA cycle length were calculated. The ablation strategy included PVI and posterior wall isolation with a minimum of 12 months follow-up. A total of 123 patients underwent CA (age 62 ± 9.1 years; CHA 2 DS 2 -VASC score 1.6 ± 1.1; left ventricular ejection fraction 48% ± 13%; left atrial area 31 ± 8.7 cm 2 ; AF duration 16 ± 17 months). PVI was achieved in 100% of patients. Multiprocedure success (MPS; freedom from AF/atrial tachycardia episodes lasting >30 seconds) was achieved in 76% of patients at 24 ± 8.1 months of follow-up after 1.2 ± 0.4 procedures. PV activity was not associated with MPS either absolutely (PV 4VAverage [MPS no vs yes: 178 ± 27 ms vs 177 ± 24 ms; P = .92], PV FVAverage [P = .69], or PV Fast [P = .82]) or as a ratio relative to the LAA cycle length (PV 4VAverage /LAA 1.05 ± 0.11 vs 1.06 ± 0.21; P = .87). The presence of PV AF (31% vs 47%; P = .13) did not predict MPS. The rapidity of PV firing or presence of fibrillation within the PV was not predictive of outcome of CA for PeAF. PV activity does not identify patients most likely to benefit from a PV-based ablation strategy. Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

PERFORMANCE EVALUATION OF A SUSTAINABLE AND ENERGY EFFICIENT RE-ROOFING TECHNOLOGY USING FIELD-TEST DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biswas, Kaushik; Miller, William A; Childs, Phillip W

2011-01-01

Three test attics were constructed to evaluate a new sustainable method of re-roofing utilizing photo-voltaic (PV) laminates, metal roofing panels, and PCM heat sink in the Envelope Systems Research Apparatus (ESRA) facility in the ORNL campus. Figure 1 is a picture of the three attic roofs located adjacent to each other. The leftmost roof is the conventional shingle roof, followed by the metal panel roof incorporating the cool-roof coating, and third from left is the roof with the PCM. On the PCM roof, the PV panels are seen as well; they're labelled from left-to-right as panels 5, 6 and 7.more » The metal panel roof consists of three metal panels with the cool-roof coating; in further discussion this is referred to as the infrared reflective (IRR) metal roof. The IRR metal panels reflect the incoming solar radiation and then quickly re-emit the remaining absorbed portion, thereby reducing the solar heat gain of the attic. Surface reflectance of the panels were measured using a Solar Spectrum Reflectometer. In the 0.35-2.0 {mu}m wavelength interval, which accounts for more than 94% of the solar energy, the IRR panels have an average reflectance of 0.303. In the infrared portion of the spectrum, the IRR panel reflectance is 0.633. The PCM roof consists of a layer of macro-encapsulated bio-based PCM at the bottom, followed by a 2-cm thick layer of dense fiberglass insulation with a reflective surface on top, and metal panels with pre-installed PV laminates on top. The PCM has a melting point of 29 C (84.2 F) and total enthalpy between 180 and 190 J/g. The PCM was macro-packaged in between two layers of heavy-duty plastic foil forming arrays of PCM cells. Two air cavities, between PCM cells and above the fiberglass insulation, helped the over-the-deck natural air ventilation. It is anticipated that during summer, this extra ventilation will help in reducing the attic-generated cooling loads. The extra ventilation, in conjunction with the PCM heat sink, are used to minimize thermal stresses due to the PV laminates on sunny days. In PV laminates sunlight is converted into electricity and heat simultaneous. In case of building integrated applications, a relatively high solar absorption of amorphous silicon laminates can be utilized during the winter for solar heating purposes with PCM providing necessary heat storage capacity. However, PV laminates may also generate increased building cooling loads during the summer months. Therefore, in this project, the PCM heat sink was to minimize summer heat gains as well. The PCM-fibreglass-PV assembly and the IRR metal panels are capable of being installed directly on top of existing shingle roofs during re-roofing, precluding the need for recycling or disposal of waste materials. The PV laminates installed on the PCM attic are PVL-144 models from Uni-Solar. Each laminate contains 22 triple junction amorphous silicon solar cells connected in series. The silicon cells are of dimensions 356 mm x 239 mm (14-in. x 9.4-in.). The PVL-144 laminate is encapsulated in durable ETFE (poly-ethylene-co-tetrafluoroethylene) high light-transmissive polymer. Table 1 lists the power, voltage and current ratings of the PVL-144 panel.« less

Risk factors for vascular complications and treatment patterns at diagnosis of 2389 PV and ET patients: Real-world data from the Swedish MPN Registry.

PubMed

Abdulkarim, Khadija; Samuelsson, Jan; Johansson, Peter; Andréasson, Björn

2017-06-01

The study mainly aimed at investigating possible correlations between peripheral blood counts, erythropoietin (EPO), JAK2 V617F mutation, and vascular complications prior to diagnosis of a population-based cohort of newly diagnosed patients with myeloproliferative neoplasms (MPN). The study comprises 1105 patients with polycythemia vera (PV) and 1284 patients with essential thrombocythemia (ET) registered in the Swedish MPN Registry. Vascular complications, prior to diagnosis, were registered in 37% of PV patients. In multivariate analysis, low hemoglobin was the only significant risk factor (P=.0120). Among ET patients, 35% had encountered a vascular complication. Risk factors for thromboembolic complications in ET were identified as age>65 years, white cell count>12×10 9 /L, and the presence of JAK2 V617F mutation (P=.0004, P=.0038, and P=.0016, respectively). A JAK2 V617F mutation was present in 71% of ET patients with vascular complications, compared to 60% in patients without. A majority of complications were thromboembolic, in both PV and ET. We conclude that vascular complications among newly diagnosed patients had affected more than one-third of our study population. Risk factors for vascular complications prior to diagnosis were lower hemoglobin in PV, and the presence of JAK2 V617F mutation, higher age, and leukocytosis in ET. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Modeling of high efficiency solar cells under laser pulse for power beaming applications

NASA Technical Reports Server (NTRS)

Jain, Raj K.; Landis, Geoffrey A.

1994-01-01

Solar cells have been used to convert sunlight to electrical energy for many years and also offer great potential for non-solar energy conversion applications. Their greatly improved performance under monochromatic light compared to sunlight, makes them suitable as photovoltaic (PV) receivers in laser power beaming applications. Laser beamed power to a PV array receiver could provide power to satellites, an orbital transfer vehicle, or a lunar base. Gallium arsenide (GaAs) and indium phosphide (InP) solar cells have calculated efficiencies of more than 50 percent under continuous illumination at the optimum wavelength. Currently high power free-electron lasers are being developed which operate in pulsed conditions. Understanding cell behavior under a laser pulse is important in the selection of the solar cell material and the laser. An experiment by NAsA lewis and JPL at the AVLIS laser facility in Livermore, CA presented experimental data on cell performance under pulsed laser illumination. Reference 5 contains an overview of technical issues concerning the use of solar cells for laser power conversion, written before the experiments were performed. As the experimental results showed, the actual effects of pulsed operation are more complicated. Reference 6 discusses simulations of the output of GaAs concentrator solar cells under pulsed laser illumination. The present paper continues this work, and compares the output of Si and GaAs solar cells.

A novel anti-theft security system for photovoltaic modules

NASA Astrophysics Data System (ADS)

Khan, Wasif Ali; Lim, Boon-Han; Lai, An-Chow; Chong, Kok-Keong

2017-04-01

Solar farms are considered as easy target for thieves because of insufficient protection measures. Existing anti-theft approaches are based on system level and are not very preventive and efficient because these can be bypassed with some technical knowledge. Additionally, it is difficult for security guards to tackle them as robbers come in a form of a gang equipped with heavy weapons. In this paper, a low power auto shut-off and non-destructive system is proposed for photovoltaic (PV) modules to achieve better level of security at module level. In proposed method, the power generation function of the PV module will be shut-off internally and cannot be re-activated by unauthorized personnel, in the case of theft. Hence, the PV module will not be functional even sold to new customers. The system comprises of a microcontroller, a low power position sensor, a controllable semiconductor switch and a wireless reactive-able system. The anti-theft system is developed to be laminated inside PV module and will be interconnected with solar cells so it becomes difficult for thieves to temper. The position of PV module is retrieved by position sensor and stored in a microcontroller as an initial reference value. Microcontroller uses this stored reference value to control power supply of PV module via power switch. The stored reference value can be altered using wireless circuitry by following authentication protocol. It makes the system non-destructive as anti-theft function can be reset again by authorized personnel, if it is recovered after theft or moved for maintenance purposes. The research component includes the design of a position sensing circuit, an auto shut-off circuit, a reactive-able wireless security protection algorithm and finally the integration of the multiple circuits.

Photovoltaics as a terrestrial energy source. Volume 2: System value

NASA Technical Reports Server (NTRS)

Smith, J. L.

1980-01-01

Assumptions and techniques employed by the electric utility industry and other electricity planners to make estimates of the future value of photovoltaic (PV) systems interconnected with U.S. electric utilities were examined. Existing estimates of PV value and their interpretation and limitations are discussed. PV value is defined as the marginal private savings accruing to potential PV owners. For utility-owned PV systems, these values are shown to be the after-tax savings in conventional fuel and capacity displaced by the PV output. For non-utility-owned (distributed) systems, the utility's savings in fuel and capacity must first be translated through the electric rate structure (prices) to the potential PV system owner. Base-case estimates of the average value of PV systems to U.S. utilities are presented. The relationship of these results to the PV Program price goals and current energy policy is discussed; the usefulness of PV output quantity goals is also reviewed.

Photovoltaic performance and reliability workshop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroposki, B

1996-10-01

This proceedings is the compilation of papers presented at the ninth PV Performance and Reliability Workshop held at the Sheraton Denver West Hotel on September 4--6, 1996. This years workshop included presentations from 25 speakers and had over 100 attendees. All of the presentations that were given are included in this proceedings. Topics of the papers included: defining service lifetime and developing models for PV module lifetime; examining and determining failure and degradation mechanisms in PV modules; combining IEEE/IEC/UL testing procedures; AC module performance and reliability testing; inverter reliability/qualification testing; standardization of utility interconnect requirements for PV systems; need activitiesmore » to separate variables by testing individual components of PV systems (e.g. cells, modules, batteries, inverters,charge controllers) for individual reliability and then test them in actual system configurations; more results reported from field experience on modules, inverters, batteries, and charge controllers from field deployed PV systems; and system certification and standardized testing for stand-alone and grid-tied systems.« less

Nanosecond pulsed laser ablated sub-10 nm silicon nanoparticles for improving photovoltaic conversion efficiency of commercial solar cells

NASA Astrophysics Data System (ADS)

Rasouli, H. R.; Ghobadi, A.; Ulusoy Ghobadi, T. G.; Ates, H.; Topalli, K.; Okyay, A. K.

2017-10-01

In this paper, we demonstrate the enhancement of photovoltaic (PV) solar cell efficiency using luminescent silicon nanoparticles (Si-NPs). Sub-10 nm Si-NPs are synthesized via pulsed laser ablation technique. These ultra-small Si nanoparticles exhibit photoluminescence (PL) character tics at 425 and 517 nm upon excitation by ultra-violet (UV) light. Therefore, they can act as secondary light sources that convert high energetic photons to ones at visible range. This down-shifting property can be a promising approach to enhance PV performance of the solar cell, regardless of its type. As proof-of-concept, polycrystalline commercial solar cells with an efficiency of ca 10% are coated with these luminescent Si-NPs. The nanoparticle-decorated solar cells exhibit up to 1.64% increase in the external quantum efficiency with respect to the uncoated reference cells. According to spectral photo-responsivity characterizations, the efficiency enhancement is stronger in wavelengths below 550 nm. As expected, this is attributed to down-shifting via Si-NPs, which is verified by their PL characteristics. The results presented here can serve as a beacon for future performance enhanced devices in a wide range of applications based on Si-NPs including PVs and LED applications.

Estimation of PV energy production based on satellite data

NASA Astrophysics Data System (ADS)

Mazurek, G.

2015-09-01

Photovoltaic (PV) technology is an attractive source of power for systems without connection to power grid. Because of seasonal variations of solar radiation, design of such a power system requires careful analysis in order to provide required reliability. In this paper we present results of three-year measurements of experimental PV system located in Poland and based on polycrystalline silicon module. Irradiation values calculated from results of ground measurements have been compared with data from solar radiation databases employ calculations from of satellite observations. Good convergence level of both data sources has been shown, especially during summer. When satellite data from the same time period is available, yearly and monthly production of PV energy can be calculated with 2% and 5% accuracy, respectively. However, monthly production during winter seems to be overestimated, especially in January. Results of this work may be helpful in forecasting performance of similar PV systems in Central Europe and allow to make more precise forecasts of PV system performance than based only on tables with long time averaged values.

Targeting malaria parasite proteins to the erythrocyte.

PubMed

Templeton, Thomas J; Deitsch, Kirk W

2005-09-01

The intraerythrocytic stages of the protozoan parasite Plasmodium falciparum reside within a parasitophorous vacuole (PV) and set up unique "extraparasite, intraerythrocyte" protein-trafficking pathways that target parasite-encoded proteins to the erythrocyte cytoplasm and cell surface. Two recent articles report the identification of trafficking motifs that regulate the transport of parasite-encoded proteins across the PV. These articles greatly aid the annotation of the parasite "secretome" catalog of proteins that are targeted to the erythrocyte cytoplasm or cell membrane.

Photovoltaics Fact Sheet

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2016-02-01

This fact sheet is an overview of the Photovoltaics (PV) subprogram at the U.S. Department of Energy SunShot Initiative. The U.S. Department of Energy (DOE)’s Solar Energy Technologies Office works with industry, academia, national laboratories, and other government agencies to advance solar PV, which is the direct conversion of sunlight into electricity by a semiconductor, in support of the goals of the SunShot Initiative. SunShot supports research and development to aggressively advance PV technology by improving efficiency and reliability and lowering manufacturing costs. SunShot’s PV portfolio spans work from early-stage solar cell research through technology commercialization, including work on materials,more » processes, and device structure and characterization techniques.« less

Monte Carlo ray-tracing simulations of luminescent solar concentrators for building integrated photovoltaics

NASA Astrophysics Data System (ADS)

Leow, Shin Woei; Corrado, Carley; Osborn, Melissa; Carter, Sue A.

2013-09-01

Luminescent solar concentrators (LSCs) have the ability to receive light from a wide range of angles, concentrating the captured light onto small photo active areas. This enables greater incorporation of LSCs into building designs as windows, skylights and wall claddings in addition to rooftop installations of current solar panels. Using relatively cheap luminescent dyes and acrylic waveguides to effect light concentration onto lesser photovoltaic (PV) cells, there is potential for this technology to approach grid price parity. We employ a panel design in which the front facing PV cells collect both direct and concentrated light ensuring a gain factor greater than one. This also allows for flexibility in determining the placement and percentage coverage of PV cells during the design process to balance reabsorption losses against the power output and level of light concentration desired. To aid in design optimization, a Monte-Carlo ray tracing program was developed to study the transport of photons and loss mechanisms in LSC panels. The program imports measured absorption/emission spectra and transmission coefficients as simulation parameters with interactions of photons in the panel determined by comparing calculated probabilities with random number generators. LSC panels with multiple dyes or layers can also be simulated. Analysis of the results reveals optimal panel dimensions and PV cell layouts for maximum power output for a given dye concentration, absorbtion/emission spectrum and quantum efficiency.

A state-of-the-art compact SiC photovoltaic inverter with maximum power point tracking function

NASA Astrophysics Data System (ADS)

Ando, Yuji; Oku, Takeo; Yasuda, Masashi; Ushijima, Kazufumi; Matsuo, Hiroshi; Murozono, Mikio

2018-01-01

We have developed a 150-W SiC-based photovoltaic (PV)-inverter with the maximum power point tracking (MPPT) function. The newly developed inverter achieved a state-of-the-art combination of the weight (0.79 kg) and the volume (790 mm3) as a 150-250 W class PV-inverter. As compared to the original version that we have previously reported, the weight and volume were decreased by 37% and 38%, respectively. This compactness originated from the optimized circuit structure and the increased density of a wiring circuit. Conversion efficiencies of the MPPT charge controller and the direct current (DC)-alternating current (AC) converter reached 96.4% and 87.6%, respectively. These efficiency values are comparable to those for the original version. We have developed a PV power generation system consisting of this inverter, a spherical Si solar cell module, and a 15-V Li-ion laminated battery. The total weight of the system was below 6 kg. The developed system exhibited stable output power characteristics, even when the weather conditions were fluctuated. These compactness, high efficiencies, and excellent stability clearly indicated the feasibility of SiC power devices even for sub-kW class PV power generation systems.

Clinical and hematological presentation of children and adolescents with polycythemia vera.

PubMed

Cario, Holger; McMullin, Mary Frances; Pahl, Heike L

2009-08-01

Polycythemia vera (PV) in children and adolescents is very rare. Data on clinical and laboratory evaluations as well as on treatment modalities are sparse. Here, we report the long-term clinical course of a PV patient first diagnosed more than 40 years ago at age 12. In addition, after a systematic review of the scientific medical literature, clinical and hematological data of 35 patients (19 female and 17 male) from 25 previous reports are summarized. Three patients developed PV following antecedent hematological malignancies. Budd-Chiari syndrome was diagnosed in seven patients indicating a particular risk of young patients of developing this disorder. One patient presented with ischemic stroke, one patient with gangrene, and three patients with severe hemorrhage. Three patients died from disease-related complications. Hematocrit levels and platelet counts were not correlated with disease severity. Leukocytosis >15 x 10(9)/L was present in 9/35 patients and associated with a thromboembolic or hemorrhagic complication in seven patients. The few available data on molecular genetics and endogenous erythroid colony growth indicate changes comparable to those detectable in adult patients. Treatment varied enormously. It included aspirin, phlebotomy, hydroxycarbamide, busulfan, melphalan, pyrimethamine, and interferon-alpha. Two patients successfully underwent stem cell transplantation. Currently, it is impossible to treat an individual pediatric PV patient with an evidence-based regimen.

Wavelength-Selective Photovoltaics for Power-generating Greenhouses

NASA Astrophysics Data System (ADS)

Carter, Sue; Loik, Michael; Shugar, David; Corrado, Carley; Wade, Catherine; Alers, Glenn

2014-03-01

While photovoltaic (PV) technologies are being developed that have the potential for meeting the cost target of 0.50/W per module, the cost of installation combined with the competition over land resources could curtail the wide scale deployment needed to generate the Terrawatts per year required to meet the world's electricity demands. To be cost effective, such large scale power generation will almost certainly require PV solar farms to be installed in agricultural and desert areas, thereby competing with food production, crops for biofuels, or the biodiversity of desert ecosystems. This requirement has put the PV community at odds with both the environmental and agricultural groups they would hope to support through the reduction of greenhouse gas emissions. A possible solution to this challenge is the use of wavelength-selective solar collectors, based on luminescent solar concentrators, that transmit wavelengths needed for plant growth while absorbing the remaining portions of the solar spectrum and converting it to power. Costs are reduced through simultaneous use of land for both food and power production, by replacing the PV cells by inexpensive long-lived luminescent materials as the solar absorber, and by integrating the panels directly into existing greenhouse or cold frames. Results on power generation and crop yields for year-long trials done at academic and commercial greenhouse growers in California will be presented.

Clinical and hematological presentation of children and adolescents with polycythemia vera

PubMed Central

McMullin, Mary Frances; Pahl, Heike L.

2014-01-01

Polycythemia vera (PV) in children and adolescents is very rare. Data on clinical and laboratory evaluations as well as on treatment modalities are sparse. Here, we report the long-term clinical course of a PV patient first diagnosed more than 40 years ago at age 12. In addition, after a systematic review of the scientific medical literature, clinical and hematological data of 35 patients (19 female and 17 male) from 25 previous reports are summarized. Three patients developed PV following antecedent hematological malignancies. Budd–Chiari syndrome was diagnosed in seven patients indicating a particular risk of young patients of developing this disorder. One patient presented with ischemic stroke, one patient with gangrene, and three patients with severe hemorrhage. Three patients died from disease-related complications. Hematocrit levels and platelet counts were not correlated with disease severity. Leukocytosis >15×109/L was present in 9/35 patients and associated with a thromboembolic or hemorrhagic complication in seven patients. The few available data on molecular genetics and endogenous erythroid colony growth indicate changes comparable to those detectable in adult patients. Treatment varied enormously. It included aspirin, phlebotomy, hydroxycarbamide, busulfan, melphalan, pyrimethamine, and interferon-alpha. Two patients successfully underwent stem cell transplantation. Currently, it is impossible to treat an individual pediatric PV patient with an evidence-based regimen. PMID:19468728

Martian Polar Vortices: Comparison of Reanalyses

NASA Technical Reports Server (NTRS)

Waugh, D. W.; Toigo, A. D.; Guzewich, S. D.; Greybush, S. J.; Wilson, R. J.; Montabone, L.

2016-01-01

The structure and evolution of the Martian polar vortices is examined using two recently available reanalysis systems: version 1.0 of the Mars Analysis Correction Data Assimilation (MACDA) and a preliminary version of the Ensemble Mars Atmosphere Reanalysis System (EMARS). There is quantitative agreement between the reanalyses in the lower atmosphere, where Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) data are assimilated, but there are differences at higher altitudes reflecting differences in the free-running general circulation model simulations used in the two reanalyses. The reanalyses show similar potential vorticity (PV) structure of the vortices: There is near-uniform small PV equatorward of the core of the westerly jet, steep meridional PV gradients on the polar side of the jet core, and a maximum of PV located off of the pole. In maps of 30 sol mean PV, there is a near-continuous elliptical ring of high PV with roughly constant shape and longitudinal orientation from fall to spring. However, the shape and orientation of the vortex varies on daily time scales, and there is not a continuous ring of PV but rather a series of smaller scale coherent regions of high PV. The PV structure of the Martian polar vortices is, as has been reported before, very different from that of Earth's stratospheric polar vortices, but there are similarities with Earth's tropospheric vortices which also occur at the edge of the Hadley Cell, and have near-uniform small PV equatorward of the jet, and a large increase of PV poleward of the jet due to increased stratification.

Martian polar vortices: Comparison of reanalyses

NASA Astrophysics Data System (ADS)

Waugh, D. W.; Toigo, A. D.; Guzewich, S. D.; Greybush, S. J.; Wilson, R. J.; Montabone, L.

2016-09-01

The structure and evolution of the Martian polar vortices is examined using two recently available reanalysis systems: version 1.0 of the Mars Analysis Correction Data Assimilation (MACDA) and a preliminary version of the Ensemble Mars Atmosphere Reanalysis System (EMARS). There is quantitative agreement between the reanalyses in the lower atmosphere, where Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) data are assimilated, but there are differences at higher altitudes reflecting differences in the free-running general circulation model simulations used in the two reanalyses. The reanalyses show similar potential vorticity (PV) structure of the vortices: There is near-uniform small PV equatorward of the core of the westerly jet, steep meridional PV gradients on the polar side of the jet core, and a maximum of PV located off of the pole. In maps of 30 sol mean PV, there is a near-continuous elliptical ring of high PV with roughly constant shape and longitudinal orientation from fall to spring. However, the shape and orientation of the vortex varies on daily time scales, and there is not a continuous ring of PV but rather a series of smaller scale coherent regions of high PV. The PV structure of the Martian polar vortices is, as has been reported before, very different from that of Earth's stratospheric polar vortices, but there are similarities with Earth's tropospheric vortices which also occur at the edge of the Hadley Cell, and have near-uniform small PV equatorward of the jet, and a large increase of PV poleward of the jet due to increased stratification.

Felis catus papillomavirus type-2 but not type-1 is detectable and transcriptionally active in the blood of healthy cats.

PubMed

Altamura, G; Jebara, G; Cardeti, G; Borzacchiello, G

2018-04-01

Papillomaviruses (PVs) are small DNA viruses that induce benign and/or malignant epithelial tumours in different species, including the domestic cat (Felis catus). To date, five F. catus papillomavirus genotypes have been identified (FcaPV-1 to FcaPV-5). FcaPV-1 is associated with skin and oral benign lesions, while FcaPV-2 infection is widely associated with feline squamous cell carcinomas. Several human and animal PVs have been found in body fluids such as peripheral blood; however, the presence of FcaPVs in non-epithelial tissues has not previously been investigated. The aim of this study was to assess the presence and gene expression of FcaPV-1 and FcaPV-2 in the blood of healthy cats. We detected FcaPV-2 DNA in 26 of 103 (25%) blood samples. Importantly, FcaPV-2 L1, E2, E6 and E7 genes were found to be expressed in 3 (25%), 11 (92%), 6 (50%) and 5 (42%) of the samples available for mRNA analysis, respectively. FcaPV-1 was not detected in any of the blood samples analysed here. The data obtained in this work suggest active and eventually productive infection of FcaPV-2 in the blood of healthy cats, implying a possible role in intra-individual spreading as well as in vertical and horizontal transmission. © 2017 Blackwell Verlag GmbH.

Analysis of a Concentrated Solar Thermophotovoltaic System with Thermal Energy Storage

NASA Astrophysics Data System (ADS)

Seyf, Hamid Reza; Henry, Asegun

2017-01-01

We analyzed a high temperature concentrated solar thermophotovoltaic (TPV) system with thermal energy storage (TES), which is enabled by the potential usage of liquid metal as a high temperature heat transfer fluid. The system concept combines the great advantages of TES with the potential for low cost and high performance derived from photovoltaic cells fabricated on reusable substrates, with a high reflectivity back reflector for photon recycling. The TES makes the electricity produced dispatchable, and thus the system studied should be compared to technologies such as concentrated solar power (CSP) with TES (e.g., using a turbine) or PV with electrochemical batteries, instead of direct and intermittent electricity generation from flat plate PV alone. Thus, the addition of TES places the system in a different class than has previously been considered and based on the model results, appears worthy of increased attention. The system level analysis presented identifies important cell level parameters that have the greatest impact on the overall system performance, and as a result can help to set the priorities for future TPV cell development.

Analysis of a Concentrated Solar Thermophotovoltaic System with Thermal Energy Storage

NASA Astrophysics Data System (ADS)

Seyf, Hamid Reza; Henry, Asegun

We analyzed a high temperature concentrated solar thermophotovoltaic (TPV) system with thermal energy storage (TES), which is enabled by the potential usage of liquid metal as a high temperature heat transfer fluid. The system concept combines the great advantages of TES with the potential for low cost and high performance derived from photovoltaic cells fabricated on reusable substrates, with a high reflectivity back reflector for photon recycling. The TES makes the electricity produced dispatchable, and thus the system studied should be compared to technologies such as concentrated solar power (CSP) with TES (e.g., using a turbine) or PV with electrochemical batteries, instead of direct and intermittent electricity generation from flat plate PV alone. Thus, the addition of TES places the system in a different class than has previously been considered and based on the model results, appears worthy of increased attention. The system level analysis presented identifies important cell level parameters that have the greatest impact on the overall system performance, and as a result can help to set the priorities for future TPV cell development.

Device Performance | Photovoltaic Research | NREL

Science.gov Websites

Device Performance Device Performance PV Calibrations Blog Check out the latest updates from the PV than 190 person-years. Capabilities Our capabilities for measuring key performance parameters of solar cells and modules include the use of various solar simulators and tools to measure current-voltage and

Morphological Manifestations of Parvovirus B19 Infection in the Bone Marrow.

DTIC Science & Technology

1997-01-09

Parvovirus B19 (PV B19 ) preferentially infects erythroid progenitor cells in the bone marrow, frequently causing anemia along with transient aplastic...infection. We devised a highly sensitive two-round, nested PCR procedure to detect PV B19 . Eight of 78 clinical specimens from individuals with

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marion, Bill; Smith, Benjamin

Using performance data from some of the millions of installed photovoltaic (PV) modules with micro-inverters may afford the opportunity to provide ground-based solar resource data critical for developing PV projects. The method used back-solves for the direct normal irradiance (DNI) and the diffuse horizontal irradiance (DHI) from the micro-inverter ac production data. When the derived values of DNI and DHI were then used to model the performance of other PV systems, the annual mean bias deviations were within +/- 4%, and only 1% greater than when the PV performance was modeled using high quality irradiance measurements. An uncertainty analysis showsmore » the method better suited for modeling PV performance than using satellite-based global horizontal irradiance.« less

Integrating More Solar with Smart Inverters: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoke, Anderson F; Giraldez Miner, Julieta I; Symko-Davies, Martha

In Hawai'i, the relatively high cost of electricity costs coupled with various incentives have made it cost-effective to install solar photovoltaics (PV) on residential homes and larger central-station PV plants. On some of the islands, PV has reached over 50% of the installed generation capacity base. To make sure these inverter-based PV plants can maintain stable and safe operations, new smart inverter functionality is being evaluated and demonstrated at significant scale across the islands This paper describes research conducted to validate high PV penetration scenarios with smart inverters and recent progress on the use of these advanced inverter grid supportmore » functions in actual power grids in Hawai'i.« less

Climate, air quality and human health benefits of various solar photovoltaic deployment scenarios in China in 2030

NASA Astrophysics Data System (ADS)

Yang, Junnan; Li, Xiaoyuan; Peng, Wei; Wagner, Fabian; Mauzerall, Denise L.

2018-06-01

Solar photovoltaic (PV) electricity generation can greatly reduce both air pollutant and greenhouse gas emissions compared to fossil fuel electricity generation. The Chinese government plans to greatly scale up solar PV installation between now and 2030. However, different PV development pathways will influence the range of air quality and climate benefits. Benefits depend on how much electricity generated from PV is integrated into power grids and the type of power plant displaced. Using a coal-intensive power sector projection as the base case, we estimate the climate, air quality, and related human health benefits of various 2030 PV deployment scenarios. We use the 2030 government goal of 400 GW installed capacity but vary the location of PV installation and the extent of inter-provincial PV electricity transmission. We find that deploying distributed PV in the east with inter-provincial transmission maximizes potential CO2 reductions and air quality-related health benefits (4.2% and 1.2% decrease in national total CO2 emissions and air pollution-related premature deaths compared to the base case, respectively). Deployment in the east with inter-provincial transmission results in the largest benefits because it maximizes displacement of the dirtiest coal-fired power plants and minimizes PV curtailment, which is more likely to occur without inter-provincial transmission. We further find that the maximum co-benefits achieved with deploying PV in the east and enabling inter-provincial transmission are robust under various maximum PV penetration levels in both provincial and regional grids. We find large potential benefits of policies that encourage distributed PV deployment and facilitate inter-provincial PV electricity transmission in China.

Appraising into the Sun: Six-State Solar Home Paired-Sale Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence Berkeley National Laboratory

Although residential solar photovoltaic (PV) installations have proliferated, PV systems on some U.S. homes still receive no value during an appraisal because comparable home sales are lacking. To value residential PV, some previous studies have employed paired-sales appraisal methods to analyze small PV home samples in depth, while others have used statistical methods to analyze large samples. Our first-of-its-kind study connects the two approaches. It uses appraisal methods to evaluate sales price premiums for owned PV systems on single-unit detached houses that were also evaluated in a large statistical study. Independent appraisers evaluated 43 recent home sales pairs in sixmore » states: California, Oregon, Florida, Maryland, North Carolina, and Pennsylvania. We compare these results with contributory-value estimates—based on income (using the PV Value® tool), gross cost, and net cost—as well as hedonic modeling results from the recent statistical study. The results provide strong, appraisal-based evidence of PV premiums in all states. More importantly, the results support the use of cost- and incomebased PV premium estimates when paired-sales analysis is impossible. PV premiums from the paired-sales analysis are most similar to net PV cost estimates. PV Value® income results generally track the appraised premiums, although conservatively. The appraised premiums are in agreement with the hedonic modeling results as well, which bolsters the suitability of both approaches for estimating PV home premiums. Therefore, these results will benefit valuation professionals and mortgage lenders who increasingly are encountering homes equipped with PV and need to understand the factors that can both contribute to and detract from market value.« less

Desmoglein 3-specific T regulatory 1 cells consist of two subpopulations with differential expression of the transcription factor Foxp3

PubMed Central

Veldman, Christian; Pahl, Andreas; Hertl, Michael

2009-01-01

Pemphigus vulgaris (PV) is an autoimmune bullous skin disorder associated with autoantibodies against desmoglein (Dsg) 3. An imbalance of type 1 regulatory T (Tr1) cells and T helper type 2 (Th2) cells specific for Dsg3 may be critical for the loss of tolerance against Dsg3 in PV. Within the population of Dsg3-responsive, interleukin (IL)-10-secreting Tr1 cell clones, two major subpopulations were identified and sorted by fluorescence-activated cell sorting (FACS) based on their size and granularity. Upon in vitro culture, the larger subpopulation differentiated back into the two former subpopulations of the Tr1 cell clones, while the smaller subpopulation died within 2 weeks. The smaller subpopulation of the Tr1 cell clones was characterized by the expression of Foxp3, the secretion of IL-10, transforming growth factor (TGF)-β and IL-5 upon stimulation with Dsg3, a proliferative response to IL-2 but not to Dsg3 or mitogenic stimuli, and an inhibitory effect on the proliferative response of Dsg3-responsive Th clones in a Dsg3-specific manner. In contrast, the larger subpopulation showed a Th-like phenotype, lacking Foxp3, cytotoxic T-lymphocyte antigen 4 (CTLA4) and glucocorticoid-induced tumour necrosis factor receptor (GITR) expression and IL-2 secretion, and did not mount a proliferative response to Dsg3 and mitogenic stimuli. The two Tr1 subpopulations showed expression of identical T-cell receptor (TCR) Vβ chains which varied among the PV patients studied. Upon inhibition of Foxp3, the smaller Tr1 subpopulation developed a proliferate response to Dsg3 and mitogenic stimuli, no longer suppressed Dsg3-specific Th cells, lost expression of GITR and CTLA4 and secreted IL-2. Thus, our observations suggest a distinct relationship between Dsg3-specific Tr1 and Th-like cells which may be critical for the continuous generation and survival of Dsg3-specific Tr1 cells. PMID:18800988

Simulation of an active cooling system for photovoltaic modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelhakim, Lotfi

Photovoltaic cells are devices that convert solar radiation directly into electricity. However, solar radiation increases the photovoltaic cells temperature [1] [2]. The temperature has an influence on the degradation of the cell efficiency and the lifetime of a PV cell. This work reports on a water cooling technique for photovoltaic panel, whereby the cooling system was placed at the front surface of the cells to dissipate excess heat away and to block unwanted radiation. By using water as a cooling medium for the photovoltaic solar cells, the overheating of closed panel is greatly reduced without prejudicing luminosity. The water alsomore » acts as a filter to remove a portion of solar spectrum in the infrared band but allows transmission of the visible spectrum most useful for the PV operation. To improve the cooling system efficiency and electrical efficiency, uniform flow rate among the cooling system is required to ensure uniform distribution of the operating temperature of the PV cells. The aims of this study are to develop a 3D thermal model to simulate the cooling and heat transfer in Photovoltaic panel and to recommend a cooling technique for the PV panel. The velocity, pressure and temperature distribution of the three-dimensional flow across the cooling block were determined using the commercial package, Fluent. The second objective of this work is to study the influence of the geometrical dimensions of the panel, water mass flow rate and water inlet temperature on the flow distribution and the solar panel temperature. The results obtained by the model are compared with experimental results from testing the prototype of the cooling device.« less

Lightweight, Flexible Solar Cells on Stainless Steel Foil and Polymer for Space and Stratospheric Applications

NASA Technical Reports Server (NTRS)

Beernink, Kevin; Guha, Subhendu; Yang, Jeff; Banerjee, Arindam; Lord, Ken; DeMaggio, Greg; Liu, Frank; Pietka, Ginger; Johnson, Todd; Reinhout, Melanie;

A GUI Based Software for Sizing Stand Alone AC Coupled Hybrid PV-Diesel Power System under Malaysia Climate

NASA Astrophysics Data System (ADS)

Syafiqah Syahirah Mohamed, Nor; Amalina Banu Mohamat Adek, Noor; Hamid, Nurul Farhana Abd

2018-03-01

This paper presents the development of Graphical User Interface (GUI) software for sizing main component in AC coupled photovoltaic (PV) hybrid power system based on Malaysia climate. This software provides guideline for PV system integrator to design effectively the size of components and system configuration to match the system and load requirement with geographical condition. The concept of the proposed software is balancing the annual average renewable energy generation and load demand. In this study, the PV to diesel generator (DG) ratio is introduced by considering the hybrid system energy contribution. The GUI software is able to size the main components in the PV hybrid system to meet with the set target of energy contribution ratio. The rated powers of the components to be defined are PV array, grid-tie inverter, bi-directional inverter, battery storage and DG. GUI is used to perform all the system sizing procedures to make it user friendly interface as a sizing tool for AC coupled PV hybrid system. The GUI will be done by using Visual Studio 2015 based on the real data under Malaysia Climate.

Control Strategies for the DAB Based PV Interface System

PubMed Central

El-Helw, Hadi M.; Al-Hasheem, Mohamed; Marei, Mostafa I.

2016-01-01

This paper presents an interface system based on the Dual Active Bridge (DAB) converter for Photovoltaic (PV) arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN) to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system. PMID:27560138

Alteration of S-adenosylhomocysteine levels affects lignin biosynthesis in switchgrass.

PubMed

Bai, Zetao; Qi, Tianxiong; Liu, Yuchen; Wu, Zhenying; Ma, Lichao; Liu, Wenwen; Cao, Yingping; Bao, Yan; Fu, Chunxiang

2018-04-28

Methionine (Met) synthesized from aspartate is a fundamental amino acid needed to produce S-adenosylmethionine (SAM) that is an important cofactor for the methylation of monolignols. As a competitive inhibitor of SAM-dependent methylation, the effect of S-adenosylhomocysteine (SAH) on lignin biosynthesis, however, is still largely unknown in plants. Expression levels of Cystathionine γ-synthase (PvCGS) and S-adenosylhomocysteine hydrolase1 (PvSAHH1) were downregulated by RNAi technology, respectively, in switchgrass, a dual-purpose forage and biofuel crop. The transgenic switchgrass lines were subjected to studying the impact of SAH on lignin biosynthesis. Our results showed that downregulation of PvCGS in switchgrass altered the accumulation of aspartate-derived and aromatic amino acids, reduced the content of SAH, enhanced lignin biosynthesis, and stunted plant growth. In contrast, downregulation of PvSAHH1 raised SAH levels in switchgrass, impaired the biosynthesis of both guaiacyl and syringyl lignins, and therefore significantly increased saccharification efficiency of cell walls. This work indicates that SAH plays a crucial role in monolignol methylation in switchgrass. Genetic regulation of either PvCGS or PvSAHH1 expression in switchgrass can change intracellular SAH contents and SAM to SAH ratios and therefore affect lignin biosynthesis. Thus, our study suggests that genes involved in Met metabolism are of interest as new valuable targets for cell wall bioengineering in future. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

High prevalence of turkey parvovirus in turkey flocks from Hungary experiencing enteric disease syndromes.

PubMed

Palade, Elena Alina; Demeter, Zoltán; Hornyák, Akos; Nemes, Csaba; Kisary, János; Rusvai, Miklós

2011-09-01

Samples collected in 2008 and 2009, from 49 turkey flocks of 6 to 43 days in age and presenting clinical signs of enteric disease and high mortality, were tested by polymerase chain reaction and reverse transcription-polymerase chain reaction for the presence of viruses currently associated with enteric disease (ED) syndromes: astrovirus, reovirus, rotavirus, coronavirus, adenovirus, and parvovirus. Turkey astroviruses were found in 83.67% of the cases and turkey astrovirus 2 (TAst-2) in 26.53%. The investigations directly demonstrated the high prevalence of turkey parvovirus (TuPV) in 23 flocks (46.9%) experiencing signs of ED, making this pathogen the second most identified after astroviruses. Phylogenetic analysis on a 527 base pair-long region from the NS1 gene revealed two main clusters, a chicken parvovirus (ChPV) and a TuPV group, but also the presence of a divergent branch of tentatively named "TuPV-like ChPV" strains. The 23 Hungarian TuPV strains were separately positioned in two groups from the American origin sequences in the TuPV cluster. An Avail-based restriction fragment length polymorphism assay has also been developed for the quick differentiation of TuPV, ChPV, and divergent TuPV-like ChPV strains. As most detected enteric viruses have been directly demonstrated in healthy turkey flocks as well, the epidemiology of this disease complex remains unclear, suggesting that a certain combination of pathogens, environmental factors, or both are necessary for the development of clinical signs.

Transparent contacts for stacked compound photovoltaic cells

DOEpatents

Tauke-Pedretti, Anna; Cederberg, Jeffrey; Nielson, Gregory N.; Okandan, Murat; Cruz-Campa, Jose Luis

2016-11-29

A microsystems-enabled multi-junction photovoltaic (MEM-PV) cell includes a first photovoltaic cell having a first junction, the first photovoltaic cell including a first semiconductor material employed to form the first junction, the first semiconductor material having a first bandgap. The MEM-PV cell also includes a second photovoltaic cell comprising a second junction. The second photovoltaic cell comprises a second semiconductor material employed to form the second junction, the second semiconductor material having a second bandgap that is less than the first bandgap, the second photovoltaic cell further comprising a first contact layer disposed between the first junction of the first photovoltaic cell and the second junction of the second photovoltaic cell, the first contact layer composed of a third semiconductor material having a third bandgap, the third bandgap being greater than or equal to the first bandgap.

Ovarian cycle-linked plasticity of δ-GABAA receptor subunits in hippocampal interneurons affects γ oscillations in vivo

PubMed Central

Barth, Albert M. I.; Ferando, Isabella; Mody, Istvan

2014-01-01

GABAA receptors containing δ subunits (δ-GABAARs) are GABA-gated ion channels with extra- and perisynaptic localization, strong sensitivity to neurosteroids (NS), and a high degree of plasticity. In selective brain regions they are expressed on specific principal cells and interneurons (INs), and generate a tonic conductance that controls neuronal excitability and oscillations. Plasticity of δ-GABAARs in principal cells has been described during states of altered NS synthesis including acute stress, puberty, ovarian cycle, pregnancy and the postpartum period, with direct consequences on neuronal excitability and network dynamics. The defining network events implicated in cognitive function, memory formation and encoding are γ oscillations (30–120 Hz), a well-timed loop of excitation and inhibition between principal cells and PV-expressing INs (PV + INs). The δ-GABAARs of INs can modify γ oscillations, and a lower expression of δ-GABAARs on INs during pregnancy alters γ frequency recorded in vitro. The ovarian cycle is another physiological event with large fluctuations in NS levels and δ-GABAARs. Stages of the cycle are paralleled by swings in memory performance, cognitive function, and mood in both humans and rodents. Here we show δ-GABAARs changes during the mouse ovarian cycle in hippocampal cell types, with enhanced expression during diestrus in principal cells and specific INs. The plasticity of δ-GABAARs on PV-INs decreases the magnitude of γ oscillations continuously recorded in area CA1 throughout several days in vivo during diestrus and increases it during estrus. Such recurring changes in γ magnitude were not observed in non-cycling wild-type (WT) females, cycling females lacking δ-GABAARs only on PV-INs (PV-Gabrd-/-), and in male mice during a time course equivalent to the ovarian cycle. Our findings may explain the impaired memory and cognitive performance experienced by women with premenstrual syndrome (PMS) or premenstrual dysphoric disorder (PMDD). PMID:25157218

Hybrid solar converters for maximum exergy and inexpensive dispatchable electricity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Branz, Howard M.; Regan, William; Gerst, Kacy J.

Photovoltaic (PV) solar energy systems are being deployed at an accelerating rate to supply low-carbon electricity worldwide. However, PV is unlikely to economically supply much more than 10% of the world's electricity unless there is a dramatic reduction in the cost of electricity storage. There is an important scientific and technological opportunity to address the storage challenge by developing inexpensive hybrid solar converters that collect solar heat at temperatures between about 200 and 600 °C and also incorporate PV. Since heat can be stored and converted to electricity at relatively low cost, collection of high exergy content (high temperature) solarmore » heat can provide energy that is dispatchable on demand to meet loads that are not well matched to solar insolation. However, PV cells can collect and convert much of the solar spectrum to electricity more efficiently and inexpensively than solar thermal systems. Advances in spectrum-splitting optics, high-temperature PV cells, thermal management and system design are needed for transformational hybrid converters. We propose that maximizing the exergy output from the solar converters while minimizing the cost of exergy can help propel solar energy toward a higher contribution to carbon-free electricity in the long term than the prevailing paradigm of maximizing the energy output while minimizing the cost of energy« less

Synchrotron X-Ray Topography for Encapsulation Stress/Strain and Crack Detection in Crystalline Silicon Modules

DOE PAGES

Colli, Alessandra; Attenkofer, Klaus; Raghothamachar, Balaji; ...

2016-07-14

Here in this article, we present the first experiment to prove the capabilities of X-ray topography for the direct imaging and analysis of defects, stress, and strain affecting the cell within the laminated photovoltaic (PV) module. Cracks originating from grain boundaries structures have been detected, developing along the cleavage planes of the crystal. The strain affecting the cell is clearly visualized through the bending of the metallization line images and can be easily mapped. While the recording conditions need to be optimized to maximize image contrast, this experiment demonstrates how synchrotron facilities can enable PV industry and research to characterizemore » full PV modules. Appropriate development of the technique could also lead to future use of laboratory-level X-ray sources.« less

Analysis of InxGa1-xN/Si p-n heterojunction solar cells and the effects of spontaneous and piezoelectric polarization charges

NASA Astrophysics Data System (ADS)

Zheng, Yangdong; Mihara, Akihiro; Yamamoto, Akio

2013-10-01

The band structures, current-voltage characteristics under solar illumination, and photovoltaic (PV) properties of InxGa1-xN/Si p-n heterojunction solar cells (SCs), as well as the effects of spontaneous and piezoelectric polarization (Psp-PPZ) induced charges are investigated theoretically and numerically. We find that the energy peaks on the conduction and valence bands could exponentially reduce the diffusion currents and photocurrents, thus profoundly affect the PV properties of the SCs. Except for large values, the Psp-PPZ induced interface charges have little influence on the band structures and the PV properties. These results should be useful in analysis and design for multijunction tandem InxGa1-xN/Si SC devices.

PV cells electrical parameters measurement

NASA Astrophysics Data System (ADS)

Cibira, Gabriel

2017-12-01

When measuring optical parameters of a photovoltaic silicon cell, precise results bring good electrical parameters estimation, applying well-known physical-mathematical models. Nevertheless, considerable re-combination phenomena might occur in both surface and intrinsic thin layers within novel materials. Moreover, rear contact surface parameters may influence close-area re-combination phenomena, too. Therefore, the only precise electrical measurement approach is to prove assumed cell electrical parameters. Based on theoretical approach with respect to experiments, this paper analyses problems within measurement procedures and equipment used for electrical parameters acquisition within a photovoltaic silicon cell, as a case study. Statistical appraisal quality is contributed.

The Implementation of Advanced Solar Array Technology in Future NASA Missions

NASA Technical Reports Server (NTRS)

Piszczor, Michael F.; Kerslake, Thomas W.; Hoffman, David J.; White, Steve; Douglas, Mark; Spence, Brian; Jones, P. Alan

2003-01-01

Advanced solar array technology is expected to be critical in achieving the mission goals on many future NASA space flight programs. Current PV cell development programs offer significant potential and performance improvements. However, in order to achieve the performance improvements promised by these devices, new solar array structures must be designed and developed to accommodate these new PV cell technologies. This paper will address the use of advanced solar array technology in future NASA space missions and specifically look at how newer solar cell technologies impact solar array designs and overall power system performance.

Development of a reverse transcription-loop-mediated isothermal amplification (RT-LAMP) system for a highly sensitive detection of enterovirus in the stool samples of acute flaccid paralysis cases

PubMed Central

2009-01-01

Background In the global eradication program for poliomyelitis, the laboratory diagnosis plays a critical role by isolating poliovirus (PV) from the stool samples of acute flaccid paralysis (AFP) cases. In this study, we developed a reverse transcription-loop-mediated isothermal amplification (RT-LAMP) system for a rapid and highly sensitive detection of enterovirus including PV to identify stool samples positive for enterovirus including PV. Methods A primer set was designed for RT-LAMP to detect enterovirus preferably those with PV-like 5'NTRs of the viral genome. The sensitivity of RT-LAMP system was evaluated with prototype strains of enterovirus. Detection of enterovirus from stool extracts was examined by using RT-LAMP system. Results We detected at least 400 copies of the viral genomes of PV(Sabin) strains within 90 min by RT-LAMP with the primer set. This RT-LAMP system showed a preference for Human enterovirus species C (HEV-C) strains including PV, but exhibited less sensitivity to the prototype strains of HEV-A and HEV-B (detection limits of 7,400 to 28,000 copies). Stool extracts, from which PV, HEV-C, or HEV-A was isolated in the cell culture system, were mostly positive by RT-LAMP method (positive rates of 15/16 (= 94%), 13/14 (= 93%), and 4/4 (= 100%), respectively). The positive rate of this RT-LAMP system for stool extracts from which HEV-B was isolated was lower than that of HEV-C (positive rate of 11/21 (= 52%)). In the stool samples, which were negative for enterovirus isolation by the cell culture system, we found that two samples were positive for RT-LAMP (positive rates of 2/38 (= 5.3%)). In these samples, enterovirus 96 was identified by sequence analysis utilizing a seminested PCR system. Conclusions RT-LAMP system developed in this study showed a high sensitivity comparable to that of the cell culture system for the detection of PV, HEV-A, and HEV-C, but less sensitivity to HEV-B. This RT-LAMP system would be useful for the direct detection of enterovirus from the stool extracts. PMID:20015403

Impact of High PV Penetration on the Inter-Area Oscillations in the U.S. Eastern Interconnection

DOE PAGES

You, Shutang; Kou, Gefei; Liu, Yong; ...

2017-03-31

Our study explores the impact of high-photovoltaic (PV) penetration on the inter-area oscillation modes of large-scale power grids. A series of dynamic models with various PV penetration levels are developed based on a detailed model representing the U.S. Eastern Interconnection (EI). Transient simulations are performed to investigate the change of inter-area oscillation modes with PV penetration. The impact of PV control strategies and parameter settings on inter-area oscillations is studied. This paper finds that as PV increases, the damping of the dominant oscillation mode decreases monotonically. We also observed that the mode shape varies with the PV control strategy andmore » new oscillation modes may emerge under inappropriate parameter settings in PV plant controls.« less

Development of an operation strategy for hydrogen production using solar PV energy based on fluid dynamic aspects

NASA Astrophysics Data System (ADS)

Amores, Ernesto; Rodríguez, Jesús; Oviedo, José; de Lucas-Consuegra, Antonio

2017-06-01

Alkaline water electrolysis powered by renewable energy sources is one of the most promising strategies for environmentally friendly hydrogen production. However, wind and solar energy sources are highly dependent on weather conditions. As a result, power fluctuations affect the electrolyzer and cause several negative effects. Considering these limiting effects which reduce the water electrolysis efficiency, a novel operation strategy is proposed in this study. It is based on pumping the electrolyte according to the current density supplied by a solar PV module, in order to achieve the suitable fluid dynamics conditions in an electrolysis cell. To this aim, a mathematical model including the influence of electrode-membrane distance, temperature and electrolyte flow rate has been developed and used as optimization tool. The obtained results confirm the convenience of the selected strategy, especially when the electrolyzer is powered by renewable energies.

A fault diagnosis system for PV power station based on global partitioned gradually approximation method

NASA Astrophysics Data System (ADS)

Wang, S.; Zhang, X. N.; Gao, D. D.; Liu, H. X.; Ye, J.; Li, L. R.

2016-08-01

As the solar photovoltaic (PV) power is applied extensively, more attentions are paid to the maintenance and fault diagnosis of PV power plants. Based on analysis of the structure of PV power station, the global partitioned gradually approximation method is proposed as a fault diagnosis algorithm to determine and locate the fault of PV panels. The PV array is divided into 16x16 blocks and numbered. On the basis of modularly processing of the PV array, the current values of each block are analyzed. The mean current value of each block is used for calculating the fault weigh factor. The fault threshold is defined to determine the fault, and the shade is considered to reduce the probability of misjudgments. A fault diagnosis system is designed and implemented with LabVIEW. And it has some functions including the data realtime display, online check, statistics, real-time prediction and fault diagnosis. Through the data from PV plants, the algorithm is verified. The results show that the fault diagnosis results are accurate, and the system works well. The validity and the possibility of the system are verified by the results as well. The developed system will be benefit for the maintenance and management of large scale PV array.

Ruxolitinib for the Treatment of Patients With Polycythemia Vera

PubMed Central

Kiladjian, Jean-Jacques; Winton, Elliott F.; Talpaz, Moshe; Verstovsek, Srdan

2015-01-01

SUMMARY Polycythemia vera (PV) is a hematopoietic proliferative disorder associated with Janus-associated kinase (JAK)/signal transducer and activator of transcription (STAT) pathway dysregulation resulting in erythrocytosis and, possibly, leukocytosis and thrombocytosis. Patients diagnosed with PV experience a broad range of symptoms associated with a reduced quality of life, often develop splenomegaly, and have an increased risk of death compared to age-matched subjects without PV. Current treatment options, notably hydroxyurea, help with disease management; however, insufficient efficacy or progressive resistance occurs in some patients, highlighting the need for new treatment options. Ruxolitinib is an oral JAK1/JAK2 inhibitor that has been evaluated in phase 2 and 3 clinical trials in patients with PV who are intolerant of or resistant to hydroxyurea. In this setting, ruxolitinib treatment has demonstrated normalization of blood cell counts, reduction in splenomegaly, and improvements in PV-related symptom burden. PMID:25980454

CD4+ T Cell Response Correlates with Naturally Acquired Antibodies against Plasmodium vivax Tryptophan-Rich Antigens

PubMed Central

Zeeshan, Mohammad; Tyagi, Kriti

2015-01-01

Tryptophan-rich proteins play important biological functions for the Plasmodium parasite. Plasmodium vivax contains remarkably large numbers of such proteins belonging to the “Pv-fam-a” family that need to be characterized. Earlier, we reported the presence of memory T cells and naturally acquired antibodies against 15 of these proteins in P. vivax malaria-exposed individuals (M. Zeeshan, H. Bora, and Y. D. Sharma, J Infect Dis 207:175–185, 2013, http://dx.doi.org/10.1093/infdis/jis650). Here, we sought to characterize and ascertain the cross talk between effector responses of T and B cells in malarial patients against all Pv-fam-a family proteins. Therefore, we expressed the remaining 21 of these proteins in Escherichia coli and studied the humoral and cellular immune responses based on the same parameters used in our previous study. Naturally acquired IgG antibodies were detected against all 21 antigens in P. vivax patient sera (37.7 to 94.4% seropositivity). These antigens were able to activate the lymphocytes of P. vivax-exposed individuals, and the activated CD4+ T lymphocytes produced higher levels of Th1 (interleukin-2 [IL-2] and gamma interferon [IFN-γ]) and Th2 (IL-4 and IL-10) cytokines than the healthy controls, but the response was Th2 biased. The combined results of present and previous studies seem to suggest a striking link between induction of the CD4+ T cell response and naturally acquired antibodies against all 36 proteins of the Pv-fam-a family, the majority of them having conserved sequences in the parasite population. Further work is required to utilize this information to develop immunotherapeutic treatments for this disease. PMID:25733522

Power optimization in body sensor networks: the case of an autonomous wireless EMG sensor powered by PV-cells.

PubMed

Penders, J; Pop, V; Caballero, L; van de Molengraft, J; van Schaijk, R; Vullers, R; Van Hoof, C

2010-01-01

Recent advances in ultra-low-power circuits and energy harvesters are making self-powered body sensor nodes a reality. Power optimization at the system and application level is crucial in achieving ultra-low-power consumption for the entire system. This paper reviews system-level power optimization techniques, and illustrates their impact on the case of autonomous wireless EMG monitoring. The resulting prototype, an Autonomous wireless EMG sensor power by PV-cells, is presented.

High Efficiency Solar Integrated Roof Membrane Product

DOE Office of Scientific and Technical Information (OSTI.GOV)

Partyka, Eric; Shenoy, Anil

2013-05-15

This project was designed to address the Solar Energy Technology Program objective, to develop new methods to integrate photovoltaic (PV) cells or modules within a building-integrated photovoltaic (BIPV) application that will result in lower installed cost as well as higher efficiencies of the encapsulated/embedded PV module. The technology assessment and development focused on the evaluation and identification of manufacturing technologies and equipment capable of producing such low-cost, high-efficiency, flexible BIPV solar cells on single-ply roofing membranes.

Philadelphia chromosome-negative myeloproliferative disorders: biology and treatment.

PubMed

Hoffman, Ronald; Prchal, Josef T; Samuelson, Scott; Ciurea, Stefan O; Rondelli, Damiano

2007-01-01

The Philadelphia chromosome (Ph)-negative myeloproliferative disorders (MPDs) include essential thrombocythemia (ET), idiopathic myelofibrosis (IMF), and polycythemia vera (PV). All of these disorders are clonal hematologic malignancies originating at the level of the pluripotent hematopoietic stem cell. Recently, activating mutations of the intracellular cytokine-signaling molecule JAK2 have been identified in > 90% of patients with PV and in 50% of those with IMF and ET. In addition, a mutation of the thrombopoietin receptor, MPLW515L, has been documented in some patients with IMF. Both mutations activate JAK-STAT signaling pathways and likely play a role in disease progression. Both ET and PV are associated with prolonged clinical courses associated with frequent thrombotic and hemorrhagic events, and progression to myelofibrosis and acute leukemia. IMF has a much poorer prognosis and is associated with cytopenias, splenomegaly, extramedullary hematopoiesis, and bone marrow fibrosis. Stratification of risk for the development of complications from Ph-negative MPDs has guided the identification of appropriate therapies for this population. Intermediate/high-risk IMF or myelofibrosis after ET or PV is associated with a sufficiently poor prognosis to justify the use of allogeneic stem cell transplantation, which is capable of curing such patients. Reduced-intensity conditioning in preparation for allogeneic stem cell transplantation has permitted older patients with IMF to undergo transplantation with increasing success.

Phase I/IIa study of intratumoral/intracerebral or intravenous/intracerebral administration of Parvovirus H-1 (ParvOryx) in patients with progressive primary or recurrent glioblastoma multiforme: ParvOryx01 protocol

PubMed Central

2012-01-01

Background The treatment of patients with malignant brain tumors remains a major oncological problem. The median survival of patients with glioblastoma multiforme (GBM), the most malignant type, is only 15 months after initial diagnosis and even less after tumor recurrence. Improvements of standard treatment including surgery and radio-chemotherapy have not lead to major improvements. Therefore, alternative therapeutics such as oncolytic viruses that specifically target and destroy cancer cells are under investigation. Preclinical data of oncolytic parvovirus H-1 (H-1PV) infection of glioma cells demonstrated strong cytotoxic and oncosuppressing effects, leading to a phase I/IIa trial of H-1PV in patients with recurrent GBM (ParvOryx01). ParvOryx01 is the first trial with a replication competent oncolytic virus in Germany. Methods ParvOryx01 is an open, non-controlled, two groups, intra-group dose escalation, single center, phase I/IIa trial. 18 patients with recurrent GBM will be treated in 2 groups of 9 patients each. Treatment group 1 will first receive H-1PV by intratumoral injection and second by administration into the walls of the tumor cavity during tumor resection. In treatment group 2 the virus will initially be injected intravenously and afterwards, identical to group 1, into the surrounding brain tissue during tumor removal. Main eligibility criteria are: age of 18 years, unifocal recurrent GBM, amenable to complete or subtotal resection. Dose escalation will be based on the Continual Reassessment Method. The primary objective of the trial is local and systemic safety and tolerability and to determine the maximum tolerated dose (MTD). Secondary objectives are proof of concept (PoC) and Progression-free Survival (PFS) up to 6 months. Discussion This is the first trial with H-1PV in patients with recurrent GBM. The risks for the participants appear well predictable and justified. Furthermore, ParvOryx01 will be the first assessment of combined intratumoral and intravenous application of an oncolytic virus. Due to its study design the trial will not only generate data on the local effect of H-1PV but it will also investigate the penetration of H-1PV into the tumor after systemic delivery and obtain safety data from systemic delivery possibly supporting clinical trials with H-1PV in other, non-CNS malignancies. Trial registration ClinicalTrials.gov Identifier: NCT01301430 PMID:22436661

High School Mentors in Brief: Findings from the Big Brothers Big Sisters School-Based Mentoring Impact Study. P/PV In Brief. Issue 8

ERIC Educational Resources Information Center

Jucovy, Linda; Herrera, Carla

2009-01-01

This issue of "Public/Private Ventures (P/PV) In Brief" is based on "High School Students as Mentors," a report that examined the efficacy of high school mentors using data from P/PV's large-scale random assignment impact study of Big Brothers Big Sisters school-based mentoring programs. The brief presents an overview of the findings, which…

Characterization of perovskite layer on various nanostructured silicon wafer

NASA Astrophysics Data System (ADS)

Rostan, Nur Fairuz Mohd; Sepeai, Suhaila; Ramli, Noor Fadhilah; Azhari, Ayu Wazira; Ludin, Norasikin Ahmad; Teridi, Mohd Asri Mat; Ibrahim, Mohd Adib; Zaidi, Saleem H.

2017-05-01

Crystalline silicon (c-Si) solar cell dominates 90% of photovoltaic (PV) market. The c-Si is the most mature of all PV technologies and expected to remain leading the PV technology by 2050. The attractive characters of Si solar cell are stability, long lasting and higher lifetime. Presently, the efficiency of c-Si solar cell is still stuck at 25% for one and half decades. Tandem approach is one of the attempts to improve the Si solar cell efficiency with higher bandgap layer is stacked on top of Si bottom cell. Perovskite offers a big potential to be inserted into a tandem solar cell. Perovskite with bandgap of 1.6 to 1.9 eV will be able to absorb high energy photons, meanwhile c-Si with bandgap of 1.124 eV will absorb low energy photons. The high carrier mobility, high carrier lifetime, highly compatible with both solution and evaporation techniques makes perovskite an eligible candidate for perovskite-Si tandem configuration. The solution of methyl ammonium lead iodide (MAPbI3) was prepared by single step precursor process. The perovskite layer was deposited on different c-Si surface structure, namely planar, textured and Si nanowires (SiNWs) by using spin-coating technique at different rotation speeds. The nanostructure of Si surface was textured using alkaline based wet chemical etching process and SiNW was grown using metal assisted etching technique. The detailed surface morphology and absorbance of perovskite were studied in this paper. The results show that the thicknesses of MAPbI3 were reduced with the increasing of rotation speed. In addition, the perovskite layer deposited on the nanostructured Si wafer became rougher as the etching time and rotation speed increased. The average surface roughness increased from ˜24 nm to ˜38 nm for etching time range between 5-60 min at constant low rotation speed (2000 rpm) for SiNWs Si wafer.

A peaking-regulation-balance-based method for wind & PV power integrated accommodation

NASA Astrophysics Data System (ADS)

Zhang, Jinfang; Li, Nan; Liu, Jun

2018-02-01

Rapid development of China’s new energy in current and future should be focused on cooperation of wind and PV power. Based on the analysis of system peaking balance, combined with the statistical features of wind and PV power output characteristics, a method of comprehensive integrated accommodation analysis of wind and PV power is put forward. By the electric power balance during night peaking load period in typical day, wind power installed capacity is determined firstly; then PV power installed capacity could be figured out by midday peak load hours, which effectively solves the problem of uncertainty when traditional method hard determines the combination of the wind and solar power simultaneously. The simulation results have validated the effectiveness of the proposed method.

Simultaneous microbial reduction of vanadium (V) and chromium (VI) by Shewanella loihica PV-4.

PubMed

Wang, Guangyu; Zhang, Baogang; Li, Shuang; Yang, Meng; Yin, Changcheng

2017-03-01

Toxic vanadium (V) and chromium (VI) often co-exist in wastewater from vanadium ore smelting and their reductions by bacterial strain Shewanella loihica PV-4 is realized simultaneously. After 27-d operation, 71.3% of V(V) and 91.2% of Cr(VI) were removed respectively, with citrate as organic carbon source. Enhancement of Cr(VI) bioreduction was observed with the suppressed V(V) reduction. V(IV) and Cr(III), the main reduction products, precipitated inside the organisms and attached on cell surfaces. Both membrane components containing cytochrome c and cytoplasmic fractions containing soluble proteins as well as NADH may contribute to these microbial reductions. Most Cr(VI) were reduced extracellularly and V(V) tended to be reduced through intracellular process, as revealed by mapping the microbial surface and a line scan across the cell, performed by scanning transmission electron microscopy. This study provides an efficient alternative for controlling combined pollution caused by these two metals based on microbial technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Involvement of mast cells by the malignant process in patients with Philadelphia chromosome negative myeloproliferative neoplasms.

PubMed

Wang, J; Ishii, T; Zhang, W; Sozer, S; Dai, Y; Mascarenhas, J; Najfeld, V; Zhao, Z J; Hoffman, R; Wisch, N; Xu, M

2009-09-01

The Philadelphia chromosome negative myeloproliferative neoplasms (MPNs) are clonal hematologic malignancies frequently characterized by a mutation in JAK2 (JAK2V617F). Peripheral blood (PB) CD34(+) cells from patients with polycythemia vera (PV) and primary myelofibrosis (PMF) generated in vitro significantly fewer mast cells (MCs) than normal PB CD34(+) cells. The numbers of MC progenitors assayed from MPN CD34(+) cells were, however, similar to that assayed from normal CD34(+) cells. A higher percentage of the cultured MPN MCs expressed FcvarepsilonRIalpha, CD63 and CD69 than normal MCs, suggesting that cultured MPN MCs are associated with an increased state of MC activation. Further analysis showed that a higher proportion of cultured PV and PMF MCs underwent apoptosis in vitro. By using JAK2V617F, MplW515L and chromosomal abnormalities as clonality markers, we showed that the malignant process involved MPN MCs. JAK2V617F-positive MC colonies were assayable from the PB CD34(+) cells of each of the 17 JAK2V617F positive MPN patients studied. Furthermore, erlotinib, a JAK2 inhibitor, was able to inhibit JAK2V617F-positive PV MC progenitor cells, indicating that malignant MC progenitor cells are a potential cellular target for such JAK2 inhibitor-directed therapy.

Arsenic resistance in Pteris vittata L.: identification of a cytosolic triosephosphate isomerase based on cDNA expression cloning in Escherichia coli.

PubMed

Rathinasabapathi, Bala; Wu, Shan; Sundaram, Sabarinath; Rivoal, Jean; Srivastava, Mrittunjai; Ma, Lena Q

2006-12-01

Arsenic hyperaccumulator Pteris vittata L. (Chinese brake fern) grows well in arsenic-contaminated media, with an extraordinary ability to tolerate high levels of arsenic. An expression cloning strategy was employed to identify cDNAs for the genes involved in arsenic resistance in P. vittata. Excised plasmids from the cDNA library of P. vittata fronds were introduced into Escherichia coli XL-1 Blue and plated on medium containing 4 mM of arsenate, a common form of arsenic in the environment. The deduced amino acid sequence of an arsenate-resistant clone, PV4-8, had cDNA highly homologous to plant cytosolic triosephosphate isomerases (cTPI). Cell-free extracts of PV4-8 had 3-fold higher level of triosephosphate isomerase (TPI) specific activities than that found in E. coli XL-1 Blue and had a 42 kD fusion protein immunoreactive to polyclonal antibodies raised against recombinant Solanum chacoense cTPI. The PV4-8 cDNA complemented a TPI-deficient E. coli mutant. PV4-8 expression improved arsenate resistance in E. coli WC3110, a strain deficient in arsenate reductase but not in AW3110 deficient for the whole ars operon. This is consistent with the hypothesis that PV4-8 TPI increased arsenate resistance in E. coli by directly or indirectly functioning as an arsenate reductase. When E. coli tpi gene was expressed in the same vector, bacterial arsenate resistance was not altered, indicating that arsenate tolerance was specific to P. vittata TPI. Paradoxically, P. vittata TPI activity was not more resistant to inhibition by arsenate in vitro than its bacterial counterpart suggesting that arsenate resistance of conventional TPI reaction was not the basis for the cellular arsenate resistance. P. vittata TPI activity was inhibited by incubation with reduced glutathione while bacterial TPI was unaffected. Consistent with cTPI's role in arsenate reduction, bacterial cells expressing fern TPI had significantly greater per cent of cellular arsenic as arsenite compared to cells expressing E. coli TPI. Excised frond tissue infiltrated with arsenate reduced arsenate significantly more under light than dark. This research highlights a novel role for P. vittata cTPI in arsenate reduction.

Photovoltaic Research | NREL

Science.gov Websites

the cost of solar cells, modules, and systems; and improving the reliability of PV components and Science-funded Center for Next Generation of Materials by Design. Reliability. Real-Time PV and Solar Research Solar panels line the rooftop of the parking garage at the south table mountain campus of

Mechanism of action and in vitro activity of short hybrid antimicrobial peptide PV3 against Pseudomonas aeruginosa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Memariani, Hamed; Shahbazzadeh, Delavar; Sabatier, Jean-Marc

Antimicrobial peptides are attractive candidates for developing novel therapeutic agents, since they are lethal to a broad spectrum of pathogens and have a unique low tendency for resistance development. In this study, mechanism of action and in vitro anti-pseudomonal activity of previously designed short hybrid antimicrobial peptide PV3 were investigated. Compared to ceftazidime, PV3 had not only higher antibacterial activity but also faster bactericidal activity. PV3 reduced biofilm biomass and viability of biofilm embedded bacteria in a concentration-dependent manner. Although the antimicrobial activity of PV3 was reduced in Mueller-Hinton broth (MHB) containing human serum, it was still active enough to eradicationmore » of bacteria at low concentrations. Compared with standard condition (MHB only), there was no significant decrease in antibacterial activity of PV3 against P. aeruginosa strains under 150 mM NaCl (p = 0.615) and 1 mM MgCl{sub 2} (p = 0.3466). Fluorescence microscopy and field emission scanning electron microscopy further indicated that PV3 killed bacteria by disrupting the cell membrane. Since PV3 has potent anti-pseudomonal activity and has little cytotoxicity in vitro, it seems plausible that the peptide should be further investigated with animal studies to support future pharmacological formulations and potential topical applications. - Highlights: • PV3 killed Pseudomonas aeruginosa by membrane-disrupting mechanism. • PV3 reduced biofilm biomass and viability of biofilm embedded bacteria in a concentration-dependent manner. • Short hybrid antimicrobial peptide PV3 exhibited higher and faster bactericidal activity comparing to ceftazidime.« less

Children's Exposure to Partner Violence in Homes Where Men Seek Help for Partner Violence Victimization.

PubMed

Douglas, Emily M; Hines, Denise A

2016-05-01

In the last several decades, the field of family violence has paid increasing attention to children's exposure to partner violence (CEPV). Most of this research has focused on the children of women seeking help for partner violence (PV) victimization. In this paper we examine exposure to PV among children of men who sought help for PV victimization ( n =408), as compared with children of men in a population-based sample ( n =666). We examined children's exposure to psychological, physical, and sexual PV and also examined CEPV that is perpetrated by women, men, or both partners. The results show that CEPV is higher among children of helpseeking men than among children of men from the population-based sample, and that most of that PV is perpetrated by the female partner. We did not find differences in CEPV based in child age or gender. We discuss implications for the field of family violence professionals.

Correlation between surface carbon concentration and adhesive strength at the Si cell/EVA interface in a PV module

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhere, N.G.; Wollam, M.E.; Gadre, K.S.

1997-12-31

Silicon solar cell/EVA composite is being studied with an objective to further improve the manufacturing technology of PV modules. Sample extraction and adhesion strength measurement process has been modified. Silicon and EVA samples were extracted from solar cells of new and field-deployed modules. Optical microscopy, SEM, and AES of samples from new modules revealed EVA islands covering most of the silicon cell surface indicating a cohesive failure. A good correlation was observed between the adhesive strength and surface concentration of carbon. A low carbon concentration which indicated less EVA clinging to cell surface always resulted in low adhesive strengths. Themore » correlation provides a simple technique for inferring properties of EVA.« less

In Planta Functional Analysis and Subcellular Localization of the Oomycete Pathogen Plasmopara viticola Candidate RXLR Effector Repertoire

PubMed Central

Liu, Yunxiao; Lan, Xia; Song, Shiren; Yin, Ling; Dry, Ian B.; Qu, Junjie; Xiang, Jiang; Lu, Jiang

2018-01-01

Downy mildew is one of the most destructive diseases of grapevine, causing tremendous economic loss in the grape and wine industry. The disease agent Plasmopara viticola is an obligate biotrophic oomycete, from which over 100 candidate RXLR effectors have been identified. In this study, 83 candidate RXLR effector genes (PvRXLRs) were cloned from the P. viticola isolate “JL-7-2” genome. The results of the yeast signal sequence trap assay indicated that most of the candidate effectors are secretory proteins. The biological activities and subcellular localizations of all the 83 effectors were analyzed via a heterologous Agrobacterium-mediated Nicotiana benthamiana expression system. Results showed that 52 effectors could completely suppress cell death triggered by elicitin, 10 effectors could partially suppress cell death, 11 effectors were unable to suppress cell death, and 10 effectors themselves triggered cell death. Live-cell imaging showed that the majority of the effectors (76 of 83) could be observed with informative fluorescence signals in plant cells, among which 34 effectors were found to be targeted to both the nucleus and cytosol, 29 effectors were specifically localized in the nucleus, and 9 effectors were targeted to plant membrane system. Interestingly, three effectors PvRXLR61, 86 and 161 were targeted to chloroplasts, and one effector PvRXLR54 was dually targeted to chloroplasts and mitochondria. However, western blot analysis suggested that only PvRXLR86 carried a cleavable N-terminal transit peptide and underwent processing in planta. Many effectors have previously been predicted to target organelles, however, to the best of our knowledge, this is the first study to provide experimental evidence of oomycete effectors targeted to chloroplasts and mitochondria. PMID:29706971

Highly efficient photocatalytic conversion of solar energy to hydrogen by WO3/BiVO4 core-shell heterojunction nanorods

NASA Astrophysics Data System (ADS)

Kosar, Sonya; Pihosh, Yuriy; Bekarevich, Raman; Mitsuishi, Kazutaka; Mawatari, Kazuma; Kazoe, Yutaka; Kitamori, Takehiko; Tosa, Masahiro; Tarasov, Alexey B.; Goodilin, Eugene A.; Struk, Yaroslav M.; Kondo, Michio; Turkevych, Ivan

2018-04-01

Photocatalytic splitting of water under solar light has proved itself to be a promising approach toward the utilization of solar energy and the generation of environmentally friendly fuel in a form of hydrogen. In this work, we demonstrate highly efficient solar-to-hydrogen conversion efficiency of 7.7% by photovoltaic-photoelectrochemical (PV-PEC) device based on hybrid MAPbI3 perovskite PV cell and WO3/BiVO4 core-shell nanorods PEC cell tandem that utilizes spectral splitting approach. Although BiVO4 is characterized by intrinsically high recombination rate of photogenerated carriers, this is not an issue for WO3/BiVO4 core-shell nanorods, where highly conductive WO3 cores are combined with extremely thin absorber BiVO4 shell layer. Since the BiVO4 layer is thinner than the characteristic carrier diffusion length, the photogenerated charge carriers are separated at the WO3/BiVO4 heterojunction before their recombination. Also, such architecture provides sufficient optical thickness even for extremely thin BiVO4 layer due to efficient light trapping in the core-shell WO3/BiVO4 nanorods with high aspect ratio. We also demonstrate that the concept of fill factor can be used to compare I-V characteristics of different photoanodes regarding their optimization for PV/PEC tandem devices.

Historical Analysis of Champion Photovoltaic Module Efficiencies

DOE PAGES

Kurtz, Sarah; Repins, Ingrid; Metzger, Wyatt K.; ...

2018-02-14

Champion photovoltaic (PV) cell and module efficiencies have been reported in Progress in PV since 1993. Following the evolution of these efficiencies enables researchers to track the progress of various technologies. National Renewable Energy Laboratory has maintained a historical chart of the champion cell efficiencies, but has not published a similar chart of champion module efficiencies. Here, we analyze champion module efficiencies and compare them to champion cell efficiencies to better understand technology trends over the last three decades, highlighting that, in some cases, module efficiencies exceed 90% of cell efficiencies. Recommendations are provided on how to change the datamore » collection and reporting for champion efficiencies to increase the value of these records.« less

Historical Analysis of Champion Photovoltaic Module Efficiencies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurtz, Sarah; Repins, Ingrid; Metzger, Wyatt K.

Champion photovoltaic (PV) cell and module efficiencies have been reported in Progress in PV since 1993. Following the evolution of these efficiencies enables researchers to track the progress of various technologies. National Renewable Energy Laboratory has maintained a historical chart of the champion cell efficiencies, but has not published a similar chart of champion module efficiencies. Here, we analyze champion module efficiencies and compare them to champion cell efficiencies to better understand technology trends over the last three decades, highlighting that, in some cases, module efficiencies exceed 90% of cell efficiencies. Recommendations are provided on how to change the datamore » collection and reporting for champion efficiencies to increase the value of these records.« less

Spectral and Concentration Sensitivity of Multijunction Solar Cells at High Temperature: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedman, Daniel J.; Steiner, Myles A.; Perl, Emmett E.

2017-06-14

We model the performance of two-junction solar cells at very high temperatures of ~400 degrees C and beyond for applications such as hybrid PV/solar-thermal power production, and identify areas in which the design and performance characteristics behave significantly differently than at more conventional near-room-temperature operating conditions. We show that high-temperature operation reduces the sensitivity of the cell efficiency to spectral content, but increases the sensitivity to concentration, both of which have implications for energy yield in terrestrial PV applications. For other high-temperature applications such as near-sun space missions, our findings indicate that concentration may be a useful tool to enhancemore » cell efficiency.« less

Fuzzy comprehensive evaluation for grid-connected performance of integrated distributed PV-ES systems

NASA Astrophysics Data System (ADS)

Lv, Z. H.; Li, Q.; Huang, R. W.; Liu, H. M.; Liu, D.

2016-08-01

Based on the discussion about topology structure of integrated distributed photovoltaic (PV) power generation system and energy storage (ES) in single or mixed type, this paper focuses on analyzing grid-connected performance of integrated distributed photovoltaic and energy storage (PV-ES) systems, and proposes a comprehensive evaluation index system. Then a multi-level fuzzy comprehensive evaluation method based on grey correlation degree is proposed, and the calculations for weight matrix and fuzzy matrix are presented step by step. Finally, a distributed integrated PV-ES power generation system connected to a 380 V low voltage distribution network is taken as the example, and some suggestions are made based on the evaluation results.

Development of Manufacturing Technology to Accelerate Cost Reduction of Low Concentration and

DOE Office of Scientific and Technical Information (OSTI.GOV)

Detrick, Adam

The purpose of this project was to accelerate deployment of cost-effective US-based manufacturing of Solaria’s unique c-Si module technology. This effort successfully resulted in the development of US-based manufacturing technology to support two highly-differentiated, market leading product platforms. The project was initially predicated on developing Solaria’s low-concentration PV (LCPV) module technology which at the time of the award was uniquely positioned to exceed the SunShot price goal of $0.50/Wp for standard c-Si modules. The Solaria LCPV module is a 2.5x concentrator that leverages proven, high-reliability PV module materials and low silicon cell usage into a technology package that already hadmore » the lowest direct material cost and leading Levelized Cost of Electricity (LCOE). With over 25 MW commercially deployed globally, the Solaria module was well positioned to continue to lead in PV module cost reduction. Throughout the term of the contract, market conditions changed dramatically and so to did Solaria’s product offerings to support this. However, the manufacturing technology developed for the LCPV module was successfully leveraged and optimized to support two new and different product platforms. BIPV “PowerVision” and High-efficiency “PowerXT” modules. The primary barrier to enabling high-volume PV module manufacturing in the US is the high manual labor component in certain unique aspects of our manufacturing process. The funding was used to develop unique manufacturing automation which makes the manual labor components of these key processes more efficient and increase throughput. At the core of Solaria’s product offerings are its unique and proprietary techniques for dicing and re-arranging solar cells into modules with highly-differentiated characteristics that address key gaps in the c-Si market. It is these techniques that were successfully evolved and deployed into US-based manufacturing site with SunShot funding. Today, Solaria is currently positioned to become the market leader with these two technologies over the coming 24 months largely due to the successful innovations of the underlying manufacturing technology. This success will leverage US-based manufacturing technology and the associated US-jobs to support. Solaria views the project as highly successful and a great example of SunShot funding enabling the creating of US jobs and the deployment of ubiquitous solar energy products.« less

Potential-induced degradation in photovoltaic modules: a critical review

DOE PAGES

Luo, Wei; Khoo, Yong Sheng; Hacke, Peter; ...

2016-11-21

Potential-induced degradation (PID) has received considerable attention in recent years due to its detrimental impact on photovoltaic (PV) module performance under field conditions. Both crystalline silicon (c-Si) and thin-film PV modules are susceptible to PID. While extensive studies have already been conducted in this area, the understanding of the PID phenomena is still incomplete and it remains a major problem in the PV industry. Herein, a critical review of the available literature is given to serve as a one-stop source for understanding the current status of PID research. This article also aims to provide an overview of future research pathsmore » to address PID-related issues. This paper consists of three parts. In the first part, the modelling of leakage current paths in the module package is discussed. The PID mechanisms in both c-Si and thin-film PV modules are also comprehensively reviewed. The second part summarizes various test methods to evaluate PV modules for PID. The last part focuses on studies related to PID in the omnipresent p-type c-Si PV modules. The dependence of temperature, humidity and voltage on the progression of PID is examined. Preventive measures against PID at the cell, module and system levels are illustrated. Moreover, PID recovery in standard p-type c-Si PV modules is also studied. Most of the findings from p-type c-Si PV modules are also applicable to other PV module technologies.« less

Plasmodium vivax VIR Proteins Are Targets of Naturally-Acquired Antibody and T Cell Immune Responses to Malaria in Pregnant Women.

PubMed

Requena, Pilar; Rui, Edmilson; Padilla, Norma; Martínez-Espinosa, Flor E; Castellanos, Maria Eugenia; Bôtto-Menezes, Camila; Malheiro, Adriana; Arévalo-Herrera, Myriam; Kochar, Swati; Kochar, Sanjay K; Kochar, Dhanpat K; Umbers, Alexandra J; Ome-Kaius, Maria; Wangnapi, Regina; Hans, Dhiraj; Menegon, Michela; Mateo, Francesca; Sanz, Sergi; Desai, Meghna; Mayor, Alfredo; Chitnis, Chetan C; Bardají, Azucena; Mueller, Ivo; Rogerson, Stephen; Severini, Carlo; Fernández-Becerra, Carmen; Menéndez, Clara; Del Portillo, Hernando; Dobaño, Carlota

2016-10-01

P. vivax infection during pregnancy has been associated with poor outcomes such as anemia, low birth weight and congenital malaria, thus representing an important global health problem. However, no vaccine is currently available for its prevention. Vir genes were the first putative virulent factors associated with P. vivax infections, yet very few studies have examined their potential role as targets of immunity. We investigated the immunogenic properties of five VIR proteins and two long synthetic peptides containing conserved VIR sequences (PvLP1 and PvLP2) in the context of the PregVax cohort study including women from five malaria endemic countries: Brazil, Colombia, Guatemala, India and Papua New Guinea (PNG) at different timepoints during and after pregnancy. Antibody responses against all antigens were detected in all populations, with PNG women presenting the highest levels overall. P. vivax infection at sample collection time was positively associated with antibody levels against PvLP1 (fold-increase: 1.60 at recruitment -first antenatal visit-) and PvLP2 (fold-increase: 1.63 at delivery), and P. falciparum co-infection was found to increase those responses (for PvLP1 at recruitment, fold-increase: 2.25). Levels of IgG against two VIR proteins at delivery were associated with higher birth weight (27 g increase per duplicating antibody levels, p<0.05). Peripheral blood mononuclear cells from PNG uninfected pregnant women had significantly higher antigen-specific IFN-γ TH1 responses (p=0.006) and secreted less pro-inflammatory cytokines TNF and IL-6 after PvLP2 stimulation than P. vivax-infected women (p<0.05). These data demonstrate that VIR antigens induce the natural acquisition of antibody and T cell memory responses that might be important in immunity to P. vivax during pregnancy in very diverse geographical settings.

Role of Ultraviolet Radiation in Papillomavirus-Induced Disease

PubMed Central

Uberoi, Aayushi; Yoshida, Satoshi; Frazer, Ian H.; Pitot, Henry C.; Lambert, Paul F.

2016-01-01

Human papillomaviruses are causally associated with 5% of human cancers. The recent discovery of a papillomavirus (MmuPV1) that infects laboratory mice provides unique opportunities to study the life cycle and pathogenesis of papillomaviruses in the context of a genetically manipulatable host organism. To date, MmuPV1-induced disease has been found largely to be restricted to severely immunodeficient strains of mice. In this study, we report that ultraviolet radiation (UVR), specifically UVB spectra, causes wild-type strains of mice to become highly susceptible to MmuPV1-induced disease. MmuPV1-infected mice treated with UVB develop warts that progress to squamous cell carcinoma. Our studies further indicate that UVB induces systemic immunosuppression in mice that correlates with susceptibility to MmuPV1-associated disease. These findings provide new insight into how MmuPV1 can be used to study the life cycle of papillomaviruses and their role in carcinogenesis, the role of host immunity in controlling papillomavirus-associated pathogenesis, and a basis for understanding in part the role of UVR in promoting HPV infection in humans. PMID:27244228

Role of Ultraviolet Radiation in Papillomavirus-Induced Disease.

PubMed

Uberoi, Aayushi; Yoshida, Satoshi; Frazer, Ian H; Pitot, Henry C; Lambert, Paul F

2016-05-01

Human papillomaviruses are causally associated with 5% of human cancers. The recent discovery of a papillomavirus (MmuPV1) that infects laboratory mice provides unique opportunities to study the life cycle and pathogenesis of papillomaviruses in the context of a genetically manipulatable host organism. To date, MmuPV1-induced disease has been found largely to be restricted to severely immunodeficient strains of mice. In this study, we report that ultraviolet radiation (UVR), specifically UVB spectra, causes wild-type strains of mice to become highly susceptible to MmuPV1-induced disease. MmuPV1-infected mice treated with UVB develop warts that progress to squamous cell carcinoma. Our studies further indicate that UVB induces systemic immunosuppression in mice that correlates with susceptibility to MmuPV1-associated disease. These findings provide new insight into how MmuPV1 can be used to study the life cycle of papillomaviruses and their role in carcinogenesis, the role of host immunity in controlling papillomavirus-associated pathogenesis, and a basis for understanding in part the role of UVR in promoting HPV infection in humans.

Performance comparison of protonic and sodium phosphomolybdovanadate polyoxoanion catholytes within a chemically regenerative redox cathode polymer electrolyte fuel cell

NASA Astrophysics Data System (ADS)

Ward, David B.; Gunn, Natasha L. O.; Uwigena, Nadine; Davies, Trevor J.

2018-01-01

The direct reduction of oxygen in conventional polymer electrolyte fuel cells (PEFCs) is seen by many researchers as a key challenge in PEFC development. Chemically regenerative redox cathode (CRRC) polymer electrolyte fuel cells offer an alternative approach via the indirect reduction of oxygen, improving durability and reducing cost. These systems substitute gaseous oxygen for a liquid catalyst that is reduced at the cathode then oxidised in a regeneration vessel via air bubbling. A key component of a CRRC system is the liquid catalyst or catholyte. To date, phosphomolybdovanadium polyoxometalates with empirical formula H3+nPVnMo12-nO40 have shown the most promise for CRRC PEFC systems. In this work, four catholyte formulations are studied and compared against each other. The catholytes vary in vanadium content, pH and counter ion, with empirical formulas H6PV3Mo9O40, H7PV4Mo8O40, Na3H3PV3Mo9O40 and Na4H3PV4Mo8O40. Thermodynamic properties, cell performance and regeneration rates are measured, generating new insights into how formulation chemistry affects the components of a CRRC system. The results include the best CRRC PEFC performance reported to date, with noticeable advantages over conventional PEFCs. The optimum catholyte formulation is then determined via steady state tests, the results of which will guide further optimization of the catholyte formulation.

Two-loop controller for maximizing performance of a grid-connected photovoltaic - fuel cell hybrid power plant

NASA Astrophysics Data System (ADS)

Ro, Kyoungsoo

The study started with the requirement that a photovoltaic (PV) power source should be integrated with other supplementary power sources whether it operates in a stand-alone or grid-connected mode. First, fuel cells for a backup of varying PV power were compared in detail with batteries and were found to have more operational benefits. Next, maximizing performance of a grid-connected PV-fuel cell hybrid system by use of a two-loop controller was discussed. One loop is a neural network controller for maximum power point tracking, which extracts maximum available solar power from PV arrays under varying conditions of insolation, temperature, and system load. A real/reactive power controller (RRPC) is the other loop. The RRPC meets the system's requirement for real and reactive powers by controlling incoming fuel to fuel cell stacks as well as switching control signals to a power conditioning subsystem. The RRPC is able to achieve more versatile control of real/reactive powers than the conventional power sources since the hybrid power plant does not contain any rotating mass. Results of time-domain simulations prove not only effectiveness of the proposed computer models of the two-loop controller, but also their applicability for use in transient stability analysis of the hybrid power plant. Finally, environmental evaluation of the proposed hybrid plant was made in terms of plant's land requirement and lifetime COsb2 emissions, and then compared with that of the conventional fossil-fuel power generating forms.

Nanophotonic light-trapping theory for solar cells

NASA Astrophysics Data System (ADS)

Yu, Zongfu; Raman, Aaswath; Fan, Shanhui

2011-11-01

Conventional light-trapping theory, based on a ray-optics approach, was developed for standard thick photovoltaic cells. The classical theory established an upper limit for possible absorption enhancement in this context and provided a design strategy for reaching this limit. This theory has become the foundation for light management in bulk silicon PV cells, and has had enormous influence on the optical design of solar cells in general. This theory, however, is not applicable in the nanophotonic regime. Here we develop a statistical temporal coupled-mode theory of light trapping based on a rigorous electromagnetic approach. Our theory reveals that the standard limit can be substantially surpassed when optical modes in the active layer are confined to deep-subwavelength scale, opening new avenues for highly efficient next-generation solar cells.

Impact of PID on industrial rooftop PV-installations

NASA Astrophysics Data System (ADS)

Buerhop, Claudia; Fecher, Frank W.; Pickel, Tobias; Patel, Tirth; Zetzmann, Cornelia; Camus, Christian; Hauch, Jens; Brabec, Christoph J.

2017-08-01

Potential induced degradation (PID) causes severe damage and financial losses even in modern PV-installations. In Germany, approximately 19% of PV-installations suffer from PID and resulting power loss. This paper focuses on the impact of PID in real installations and how different evaluated time intervals influence the performance ratio (PR) and the determined degradation rate. The analysis focuses exemplarily on a 314 kWp PV-system in the Atlantic coastal climate. IR-imaging is used for identifying PID without operation interruption. Historic electric performance data are available from a monitoring system for several years on system level, string level as well as punctually measured module string IV- curves. The data sets are combined for understanding the PID behavior of this PV plant. The number of PID affected cells within a string varies strongly between 1 to 22% with the string position on the building complex. With increasing number of PID-affected cells the performance ratio decreases down to 60% for daily and monthly periods. Local differences in PID evolution rates are identified. An average PR-reduction of -3.65% per year is found for the PV-plant. On the string level the degradation rate varied up to 8.8% per year depending on the string position and the time period. The analysis reveals that PID generation and evolution in roof-top installations on industrial buildings with locally varying operation conditions can be fairly complex. The results yield that local operating conditions, e.g. ambient weather conditions as well as surrounding conditions on an industrial building, seem to have a dominating impact on the PID evolution rate.

The Host Plant Metabolite Glucose Is the Precursor of Diffusible Signal Factor (DSF) Family Signals in Xanthomonas campestris

PubMed Central

Liu, Xiaoling; Wu, Ji'en; Lee, Jasmine; Chen, Shaohua; Cheng, Yingying; Zhang, Chunyan

2015-01-01

Plant pathogen Xanthomonas campestris pv. campestris produces cis-11-methyl-2-dodecenoic acid (diffusible signal factor [DSF]) as a cell-cell communication signal to regulate biofilm dispersal and virulence factor production. Previous studies have demonstrated that DSF biosynthesis is dependent on the presence of RpfF, an enoyl-coenzyme A (CoA) hydratase, but the DSF synthetic mechanism and the influence of the host plant on DSF biosynthesis are still not clear. We show here that exogenous addition of host plant juice or ethanol extract to the growth medium of X. campestris pv. campestris could significantly boost DSF family signal production. It was subsequently revealed that X. campestris pv. campestris produces not only DSF but also BDSF (cis-2-dodecenoic acid) and another novel DSF family signal, which was designated DSF-II. BDSF was originally identified in Burkholderia cenocepacia to be involved in regulation of motility, biofilm formation, and virulence in B. cenocepacia. Functional analysis suggested that DSF-II plays a role equal to that of DSF in regulation of biofilm dispersion and virulence factor production in X. campestris pv. campestris. Furthermore, chromatographic separation led to identification of glucose as a specific molecule stimulating DSF family signal biosynthesis in X. campestris pv. campestris. 13C-labeling experiments demonstrated that glucose acts as a substrate to provide a carbon element for DSF biosynthesis. The results of this study indicate that X. campestris pv. campestris could utilize a common metabolite of the host plant to enhance DSF family signal synthesis and therefore promote virulence. PMID:25681189

Coating Processes Boost Performance of Solar Cells

NASA Technical Reports Server (NTRS)

2012-01-01

NASA currently has spacecraft orbiting Mercury (MESSENGER), imaging the asteroid Vesta (Dawn), roaming the red plains of Mars (the Opportunity rover), and providing a laboratory for humans to advance scientific research in space (the International Space Station, or ISS). The heart of the technology that powers those missions and many others can be held in the palm of your hand - the solar cell. Solar, or photovoltaic (PV), cells are what make up the panels and arrays that draw on the Sun s light to generate electricity for everything from the Hubble Space Telescope s imaging equipment to the life support systems for the ISS. To enable NASA spacecraft to utilize the Sun s energy for exploring destinations as distant as Jupiter, the Agency has invested significant research into improving solar cell design and efficiency. Glenn Research Center has been a national leader in advancing PV technology. The Center s Photovoltaic and Power Technologies Branch has conducted numerous experiments aimed at developing lighter, more efficient solar cells that are less expensive to manufacture. Initiatives like the Forward Technology Solar Cell Experiments I and II in which PV cells developed by NASA and private industry were mounted outside the ISS have tested how various solar technologies perform in the harsh conditions of space. While NASA seeks to improve solar cells for space applications, the results are returning to Earth to benefit the solar energy industry.

Basic aspects for improving the energy conversion efficiency of hetero-junction organic photovoltaic cells.

PubMed

Ryuzaki, Sou; Onoe, Jun

2013-01-01

Hetero-junction organic photovoltaic (OPV) cells consisting of donor (D) and acceptor (A) layers have been regarded as next-generation PV cells, because of their fascinating advantages, such as lightweight, low fabrication cost, resource free, and flexibility, when compared to those of conventional PV cells based on silicon and semiconductor compounds. However, the power conversion efficiency (η) of the OPV cells has been still around 8%, though more than 10% efficiency has been required for their practical use. To fully optimize these OPV cells, it is necessary that the low mobility of carriers/excitons in the OPV cells and the open circuit voltage (V OC), of which origin has not been understood well, should be improved. In this review, we address an improvement of the mobility of carriers/excitons by controlling the crystal structure of a donor layer and address how to increase the V OC for zinc octaethylporphyrin [Zn(OEP)]/C60 hetero-junction OPV cells [ITO/Zn(OEP)/C60/Al]. It was found that crystallization of Zn(OEP) films increases the number of inter-molecular charge transfer (IMCT) excitons and enlarges the mobility of carriers and IMCT excitons, thus significantly improving the external quantum efficiency (EQE) under illumination of the photoabsorption band due to the IMCT excitons. Conversely, charge accumulation of photo-generated carriers in the vicinity of the donor/acceptor (D/A) interface was found to play a key role in determining the V OC for the OPV cells.

Basic aspects for improving the energy conversion efficiency of hetero-junction organic photovoltaic cells

PubMed Central

Ryuzaki, Sou; Onoe, Jun

2013-01-01

Hetero-junction organic photovoltaic (OPV) cells consisting of donor (D) and acceptor (A) layers have been regarded as next-generation PV cells, because of their fascinating advantages, such as lightweight, low fabrication cost, resource free, and flexibility, when compared to those of conventional PV cells based on silicon and semiconductor compounds. However, the power conversion efficiency (η) of the OPV cells has been still around 8%, though more than 10% efficiency has been required for their practical use. To fully optimize these OPV cells, it is necessary that the low mobility of carriers/excitons in the OPV cells and the open circuit voltage (V OC), of which origin has not been understood well, should be improved. In this review, we address an improvement of the mobility of carriers/excitons by controlling the crystal structure of a donor layer and address how to increase the V OC for zinc octaethylporphyrin [Zn(OEP)]/C60 hetero-junction OPV cells [ITO/Zn(OEP)/C60/Al]. It was found that crystallization of Zn(OEP) films increases the number of inter-molecular charge transfer (IMCT) excitons and enlarges the mobility of carriers and IMCT excitons, thus significantly improving the external quantum efficiency (EQE) under illumination of the photoabsorption band due to the IMCT excitons. Conversely, charge accumulation of photo-generated carriers in the vicinity of the donor/acceptor (D/A) interface was found to play a key role in determining the V OC for the OPV cells. PMID:23853702

Short-term PV/T module temperature prediction based on PCA-RBF neural network

NASA Astrophysics Data System (ADS)

Li, Jiyong; Zhao, Zhendong; Li, Yisheng; Xiao, Jing; Tang, Yunfeng

2018-02-01

Aiming at the non-linearity and large inertia of temperature control in PV/T system, short-term temperature prediction of PV/T module is proposed, to make the PV/T system controller run forward according to the short-term forecasting situation to optimize control effect. Based on the analysis of the correlation between PV/T module temperature and meteorological factors, and the temperature of adjacent time series, the principal component analysis (PCA) method is used to pre-process the original input sample data. Combined with the RBF neural network theory, the simulation results show that the PCA method makes the prediction accuracy of the network model higher and the generalization performance stronger than that of the RBF neural network without the main component extraction.

Mean-variance portfolio analysis data for optimizing community-based photovoltaic investment.

PubMed

Shakouri, Mahmoud; Lee, Hyun Woo

2016-03-01

The amount of electricity generated by Photovoltaic (PV) systems is affected by factors such as shading, building orientation and roof slope. To increase electricity generation and reduce volatility in generation of PV systems, a portfolio of PV systems can be made which takes advantages of the potential synergy among neighboring buildings. This paper contains data supporting the research article entitled: PACPIM: new decision-support model of optimized portfolio analysis for community-based photovoltaic investment [1]. We present a set of data relating to physical properties of 24 houses in Oregon, USA, along with simulated hourly electricity data for the installed PV systems. The developed Matlab code to construct optimized portfolios is also provided in . The application of these files can be generalized to variety of communities interested in investing on PV systems.

Intelligent control of PV system on the basis of the fuzzy recurrent neuronet*

NASA Astrophysics Data System (ADS)

Engel, E. A.; Kovalev, I. V.; Engel, N. E.

2016-04-01

This paper presents the fuzzy recurrent neuronet for PV system’s control. Based on the PV system’s state, the fuzzy recurrent neural net tracks the maximum power point under random perturbations. The validity and advantages of the proposed intelligent control of PV system are demonstrated by numerical simulations. The simulation results show that the proposed intelligent control of PV system achieves real-time control speed and competitive performance, as compared to a classical control scheme on the basis of the perturbation & observation algorithm.